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ATTREXAirborne Topical TRopopause EXperiment

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Figure 1. ATTREX Organization Chart

ATTREX Due at NASA: 6 Nov 2009

Executive Summary

Background and Scientific Importance—Recent calculations show that the climatic impact of changes in stratospheric humidity are comparable to those of increasing greenhouse gas concentrations. While the tropospheric water vapor climate feedback is reasonably well represented in global models, predictions of future changes in stratospheric humidity are highly uncertain because of gaps in our understanding of physical processes occuring in the Tropical Tropopause Layer (TTL, ~13-18 km), the region of the atmosphere that controls the composition of the stratosphere. Important and poorly understood processes include the effects of deep convection on TTL water vapor and other chemical constituents; the formation of ubiquitous thin cirrus in the TTL (which themselves have an important effect on the radiation budget and climate); regulation of stratospheric humidity by TTL thin cirrus; rates and pathways of vertical transport through the TTL; the effects of tropical waves on TTL thermal structure, dehydration, and transport; and the impact of short-lived trace gases on stratospheric ozone concentration.

Observations of TTL composition are sparse compared to those in other climatically important regions, partly because its high altitude limits aircraft sampling and partly because strong vertical gradients limit the usefulness of coarse-resolution satellite measurements. As a result, TTL transport, cloud formation, dehydration, and chemistry are crudely represented in global models. Future changes in TTL processes that will affect cloudiness as well as stratospheric humidity and ozone represent significant climate feedbacks. Thus, addressing our limitations in understanding of the TTL is critically important. We propose to address these problems with a series of TTL measurement campaigns using the unique capabilies of the long-range NASA Global Hawk (GH) unmanned aircraft system (UAS).

The proposed investigation fills several significant gaps in atmospheric science identified in the NASA Decadal Survey involving climate change, stratospheric ozone, and stratosphere-troposphere exchange. Science questions that will be addressed include the following:

1. What processes control the tropical tropopause temperature and the humidity of air entering the stratosphere (including their seasonal cycles)?

2. What are the dominant pathways for vertical transport from convective detrainment altitudes in the TTL up to the tropical tropopause in different seasons?

3. What are the formation processes, microphysical properties, and climate impact of TTL cirrus, and how do these clouds regulate the humidity of air entering the stratosphere?

4. What are the chemical and transport processes that drive the budget of ozone and ozone precursors such as short-lived halogen compounds?

5. How will TTL cirrus, stratospheric humidity, and stratospheric ozone respond to a changing climate, and what are the resulting feedback effects?


Table 1. Global Hawk Payload

Instrument Measurements

Cloud Physics Lidar (CPL) Aerosol/cloud backscatter

Ozone O3Advanced Whole Air Sampler (AWAS) Numerous tracers with varying lifetimes

UAS Chromatograph for Atmospheric Trace Species (UCATS)

O3, CH4, N2O, SF6

Picarro Cavity Ringdown Spectrometer CO2, CO

UAS Laser Hygrometer (ULH) H2O

Diode Laser Hygrometer (DLH) H2O

Hawkeye Ice crystal size distributions, habits

Solar, Infrared Radiometers Radiative fluxes

Meteorological Measurement System (MMS) Temperature, winds, turbulence

Microwave Temperature Profiler (MTP) Temperature profile

Differential Optical Absorption Spectrometer (DOAS) BrO, NO2, OClO, IO


Investigation Approach—The proposed investigation (Airborne Tropical Tropopause Experiment, ATTREX) addresses these science questions with four airborne campaigns using the GH UAS. The GH, with a 30-hr duration, a 65,000 ft ceiling, and a 1000 lb payload capacity, is uniquely suited for TTL science objectives. The proposed instruments (Table 1) will provide high spatial and temporal resolution measurements of TTL tracers with a broad range of lifetimes, cloud microphysical properties, thermodynamic variables, radiative fluxes, water vapor, and brominated gases over very large spatial domains in the tropics. Each of the proposed instruments uses state-of-the-art, demonstrated techniques. The four campaigns will explore the seasonal variability of TTL processes. GMT2 will make sustained measurements at high spatial resolution over vast geographical regions. Thus, it fills the gap between coarse-resolution satellites and single, limited-domain conventional high altitude aircraft campaigns..

The deployment schedule (Table 2) allows almost two years for post-deployment data analysis and modeling. The broad scale sustained measurements allow significant conclusions from aircraft data alone. However, combination with satellite data and modeling studies is essential both in providing context for the aircraft measurements, and validation of satellite measurements. The theory team is experienced in aircraft data analysis and cloud, transport, and chemical modeling. Trajectory analyses, process models, chemical transport models and climate models will be used to understand TTL processes in the current atmosphere, improve representations of these processes in climate models, and predict feedback effects associated with changes in TTL clouds and composition in a changing climate.



Table of Contents

ATTREX......................................................................................................................................................................................................1

Airborne Topical TRopopause EXperiment...................................................................................................................................................1

Executive Summary...................................................................................................................................................................................2

1.0. Science Investigation..........................................................................................................................................................................41.1. Science Goals and Objectives........................................................................................................................................................4

1.2 Science Objectives....................................................................................................................................................................4Measurement Requirements...........................................................................................................................................................4

2.0. Science Implementation......................................................................................................................................................................42.1. Science Investigation Concept.......................................................................................................................................................42.2. Science Data.................................................................................................................................................................................4

2.2.1 Science Traceability................................................................................................................................................................42.2.2 Data Management Plan..........................................................................................................................................................4

2.3. Science Team.................................................................................................................................................................................4

3.0. Investigation Implemenation...............................................................................................................................................................43.1. Measurement Platform System Capabilities..................................................................................................................................4

3.1.1. Global Hawk Payload Capacity...............................................................................................................................................43.1.2. Ground Control Station (GCS)................................................................................................................................................43.1.3. Global Hawk Mobile Operations Facility (GHMOF)...................................................................................................................4

3.2. Instrumentation............................................................................................................................................................................43.2.1. Mission Instrument Summary...............................................................................................................................................43.2.2. Instrument Descriptions.......................................................................................................................................................43.2.2.1. Cloud Physics Lidar (CPL)...................................................................................................................................................43.2.2.2. Ozone (O3)........................................................................................................................................................................43.2.2.3. Advanced Whole Air Sampler (AWAS)................................................................................................................................43.2.2.4. UAS Chromatograph for Atmospheric Trace Species (UCATS).............................................................................................43.2.2.5. Picarro Cavity Ringdown Spectrometer (PCRS)...................................................................................................................43.2.2.6. UAS Laser Hygrometer (ULH).............................................................................................................................................43.2.2.7. Diode Laser Hygrometer (DLH)..........................................................................................................................................43.2.2.8. Hawkeye (Lawson, Spec Inc.).............................................................................................................................................43.2.2.9. Solar, Infrared Radiometers (SSFR)....................................................................................................................................43.2.2.10. Meteorological Measurement System (MMS)....................................................................................................................43.2.2.11. Microwave Temperature Profiler (MTP).............................................................................................................................43.2.2.12. Mini-DOAS - Differential Optical Absorption Spectrometer.................................................................................................4

3.3. Development Approach................................................................................................................................................................43.3.1. Management and Planning...................................................................................................................................................43.3.2. Developmental Status..........................................................................................................................................................43.3.3. Deployment Sites.................................................................................................................................................................4

3.4. Assembly, Integration, Test...........................................................................................................................................................43.4.1. Planning...............................................................................................................................................................................43.4.2. Integration...........................................................................................................................................................................43.4.3. Testing..................................................................................................................................................................................43.4.4. Timeline...............................................................................................................................................................................4

4.0. Management.......................................................................................................................................................................................44.1. Management Approach..................................................................................................................................................................4

4.1.1. Team Member Coordination and Communication...................................................................................................................44.1.2. Reviews and Progress Reporting to ESSP...............................................................................................................................4

4.2. Risk Management..........................................................................................................................................................................44.3. Schedule.......................................................................................................................................................................................44.4. Management of Reserves, Margins, and Descope Options..............................................................................................................4



5.0. Cost and Cost Estimating Methodology...............................................................................................................................................45.1 Cost Summary................................................................................................................................................................................45.2 Cost Estimating Methodology.........................................................................................................................................................45.3 Reserves Level Justification.............................................................................................................................................................4

APPENDICES..............................................................................................................................................................................................4A. ATTREX –Cost Table.................................................................................................................................................................4B. Work Breakdown Structure (WBS)..........................................................................................................................................4C. WBS Dictionary......................................................................................................................................................................4D. Statement of Work (SOW)......................................................................................................................................................4E. Master Equipment List (MEL)..................................................................................................................................................4F. Basis of Estimate Details.............................................................................................................................................................4

WBS 1.0 Project Management, 2.0 Systems Engineering, 3.0 Safety & Investigation Assurance......................................................4WBS 4.0 Instruments.......................................................................................................................................................................4WBS 5.0 Flight System and Services...............................................................................................................................................4WBS 6.0 Investigation Operations...................................................................................................................................................4WBS 7.0 Ground System.................................................................................................................................................................4WBS 8.0 Integration and Test..........................................................................................................................................................4WBS 9.0 Science Team....................................................................................................................................................................4

G. Curriculae Vitae.....................................................................................................................................................................4Dr. Eric J. Jensen..............................................................................................................................................................................4Michael T. Gaunce...........................................................................................................................................................................4Dr. Leonhard Pfister.........................................................................................................................................................................4DR. David W. Fahey.........................................................................................................................................................................4Co-I and Flight Scientist...................................................................................................................................................................4Dr. Hanwant B. Singh,.....................................................................................................................................................................4Dr. M. Joan Alexander......................................................................................................................................................................4Dr. Matthew J. McGill.......................................................................................................................................................................4Dr. Ru-Shan Gao..............................................................................................................................................................................4Dr. Elliot L. Atlas..............................................................................................................................................................................4Dr. James W. Elkins..........................................................................................................................................................................4Dr. Steven C. Wofsy.........................................................................................................................................................................4Dr. Robert L. Herman.......................................................................................................................................................................4Glen Diskin......................................................................................................................................................................................4Dr. R. Paul Lawson...........................................................................................................................................................................4Dr. Peter Pilewskie...........................................................................................................................................................................4Dr. T. Paul Bui..................................................................................................................................................................................4Dr. Michael J. Mahoney....................................................................................................................................................................4Jochen Peter Stutz...........................................................................................................................................................................4

H. Letters of Commitment..........................................................................................................................................................4I. Current and Pending Support for PI and Co-Is..............................................................................................................................4J. Compliance with U.S. Export Laws and Regulations.....................................................................................................................4K. References.............................................................................................................................................................................4

Works Cited................................................................................................................................................................................................4


Figure 1-1. The Tropical Tropopause Layer (TTL) in the context of

the overall stratospheric circulation. Air moves upward into the

stratosphere through the TTL, where very cold temperatures

control the water vapor through condensation. Stratospheric

motion is downward at other latitudes.

Figure 1-2. Processes occurring within the Tropical Tropopause Layer

(TTL)


1.0. Science Investigation

Recent studies show that changes in stratospheric water vapor concentration have a large impact on climate. Solomon et al. (manuscript submitted to Science, 2009) calculated a radiative forcing (i.e., impact on the earth’s heat budget) from the recent (since 2000) decrease in stratospheric humidity of -0.098 W m-2, which is comparable in magnitude to the radiative forcing increase due to the increases in carbon dioxide concentration from 1996-2005 (+0.26 W m-2). Based on these calculations, they estimate that the stratospheric water decrease acted to slow the rate of surface temperature increase over the past decade by 25% compared to that expected from increases in carbon dioxide and other greenhouse gases. Despite its importance, global model predictions of the response of stratospheric humidity to a changing climate are highly uncertain. The proposed investigation will directly address this problem.

Air enters the stratosphere across the tropical tropopause (Figure 1-1), and the stratospheric water vapor concentration is controlled by processes occuring in the region of the atmosphere known as the tropical tropopause layer (TTL, Figure 1-2). TTL processes affecting the humidity of air entering the stratosphere include injection by deep convection, transport through cold tropopause regions, and freeze-drying by formation of thin cirrus. The TTL composition is poorly observed in comparison to other climatically important parts of the atmosphere, partly due to the high altitude that limits sampling with aircraft and partly due to the strong vertical gradients that limit the value of coarse-resolution satellite measurements. Insufficient understanding of TTL physical processes and poor representation of these processes in global models limits our confidence in predictions of climate feedbacks associated with changes in TTL clouds, stratospheric humidity, and stratospheric composition in a warming climate.


Figure 1-3. TTL cirrus occurrence frequency calculated from

CALIPSO measurements. From Yang et al. (2009).


The occurrence of ubiquitous TTL cirrus (which are themselves important for the earth’s radiation budget and climate), the regulation of stratospheric humidity, and the chemical composition of air entering the stratosphere are controlled by a complex interplay between rapid and slow transport processes, microphysical processes, waves, and chemistry. Deep convection links surface conditions to the upper troposphere. The strength and depth of convection affects transport of water vapor and chemical constituents and affects the generation of tropical waves. Tropical waves affect cirrus formation and drive large scale ascent in the tropics. Cirrus have direct radiative effects and also have indirect effects on water vapor concentrations that are communicated to the whole stratosphere via the Brewer-Dobson (BD) circulation (Figure 1-1). Through the BD circulation, the TTL composition has a controlling influence on production and loss rates of stratospheric ozone.

The proposed investigation (Airborne Tropical Tropopause Experiment (ATTREX) will provide sustained measurements of TTL composition, cloud properties, and radiative environment over multipe seasons and over large geographic regions required to address the shortcomings in our understanding of TTL processes and our ability to predict climate change.

1.1. Science Goals and Objectives

The proposed investigation has the following overarching science goals:

1. To improve our understanding of how deep convection, slow large-scale ascent, waves, and microphyiscs control the humidity and chemical composition of air entering the stratosphere.

2. To improve global-model predictions of feedbacks associated with future changes in TTL cirrus, stratospheric humidity, and stratospheric ozone in a changing climate.

ATTREX fills several significant gaps in atmospheric science identified in Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond (2007):

From Chapter 6, Health and Human Security, UV Dosage Forecasting, pp 159, 162

∙ Catalytic destruction of O3 from ClO, BrO, and IO concentrations in the lower stratosphere ∙ Dynamic coupling between the troposphere and stratosphere due to CO2, CH4, etc.∙ Role of convective injection of short-lived compounds through the TTL

From Chapter 9, Observational Needs and Requirements, pp 260, 265

∙ How climate is affected by the balance between sunlight absorbed and emitted infrared radiation? ∙ Composition of the atmosphere (such as greenhouse gases and aerosols), and the effects of the various atmospheric components

on radiation loss to space. ∙ Understanding the climate feedback process critical to improving climate models.∙ Reliable climate simulations require improved treatment of the processes: clouds, aerosols, and convective systems; and trace

species across the interfaces of boundary layer and free troposphere, troposphere-stratosphere.

From Chapter 9, Focus Area Beta: Measurement of Convective Transports, p 292

∙ The balance between convection and radiation in the TTL plays a major role in stratosphere-troposphere exchange, particularly with respect to the abundances of water vapor, aerosols, and halogen compounds entering the stratosphere in the tropics.


Figure 1-4. The seasonal variability of tropical tropopause temperature (left) and water vapor concentration from a variety of

state-of-the-art global models. Note the large variability in temperature (and correspondingly in H2O) between different

models, reflecting the uncertainty in processes controlling stratospheric humidity. From Eyring et al. (2006).


∙ Measure atmospheric composition through the upper troposphere and across the tropopause to understand the stratosphere-troposphere exchange.

1.2 Science Objectives

1.2.1. TTL Cirrus and Control of Stratospheric Humidity

Recent studies have shown that TTL cirrus regulate the humidity of air entering the stratosphere (e.g. Jensenand Pfister, 2004; Fueglistaler et al., 2005), the local thermal budget of the TTL (with implications for vertical transport -- Corti et al., 2006), and the net radiative flux in the tropics (Haladay and Stephens,2009). Cirrus clouds occur with very high frequency in the TTL (Figure 1-3), resulting from both detrainment from deep convection and in situ formation within the TTL. Widespread cirrus formation in the TTL is expected given the large-scale ascent that drives adiabatic cooling and increasing relative humidity. TTL cirrus are typically laminar (Massie et al., 2009), and optically thin (often referred to as subvisible clouds). A detailed understanding of the detailed TTL cirrus formation processes is necessary for quantitative prediction of their impact on the water vapor and radiation budgets. Despite the importance of stratospheric water for radiation and climate (discussed above), predictions of TTL temperature, TTL cloud formation, and ultimately stratospheric water are highly uncertain in current climate models (Figure 1-4).

Recent in situ observations indicated large supersaturations both within TTL cirrus and in clear regions near the cold tropical tropopause (Jensen et al., 2005). The existence of such large supersaturations (relative humidities with respect to ice (RHI) approaching 200%) defies theoretical expectations that ice crystals will nucleate at 160% RHI, preventing further increase in supersaturation, and that within TTL cirrus, ice crystal growth should rapidly deplete vapor in excess of saturation. However, these high-supersaturation measurements have been called into question because of persistent discrepancies in water vapor measurements made by different instruments (Jensen et al., 2008; Kramer et al., 2008).

In addition to the issues involving large supersaturations at low temperatures, there are significant gaps in our understanding of how cirrus form at very low temperatures. The conventional theory is that homogeneous freezing of aqueous aerosols dominates production of ice crystals in the upper troposphere. However, recent measurements of TTL cirrus ice concentrations, particle size distributions, and cloud extinctions are in conflict with theoretical expectations for cirrus formed via homogeneous freezing at low temperatures (1) (Jensen et al., 2009). Further, recent laboratory measurements show that mixed sulfate/organic aerosols will transition to a glassy state at low temperatures, effectively preventing homogeneous freezing nucleation (Zobrist et al.,2008; Murray, 2008). Understanding TTL cirrus formation processes (which control their microphysical properties) is important for predicting effects on radiation and the humidity of air entering the stratosphere.

Atmospheric waves are crucial to cirrus formation and regulation of water vapor concentrations in two ways. First, because ice nucleation typically requires substantial supersaturation, anomalously cold temperatures associated with waves will significantly increase the incidence of cloud formation and subsequent dehydration. Second, wave motions significantly effect air parcel cooling rates, which, in turn, impact cloud particle size distribution (rapid cooling produces many small ice crystals, slower cooling fewer larger crystals). Observations have demonstrated that TTL cirrus clouds form in the cold phases of Kelvin waves (2) (3) (Boehm and Verlinde, 2000; Holton and Gettelman, 2001; Immler at al., 2008), as well as inertia-gravity waves (Pfister at al., 2001). Jensen and Pfister (2004)



showed that wave-induced cloud formation substantially reduces water vapor at upper levels in the TTL, and recent calculations suggest that inclusion of waves in theoretical models of TTL cloud formation and water vapor may be required to reconcile discrepancies with observations. However, these models are limited by our current lack of observational knowledge of the global variations in TTL wave properties. Satellite measurements lack sufficient vertical resolution for the lower frequency waves that have the largest temperature perturbations. There is also a “measurement gap” between the mesoscale waves (up to a few 100 km) captured by conventional aircraft and the several thousand km scale waves captured by satellites.

To move forward, we need to know: (1) how inertia-gravity, Kelvin, and other equatorial gravity wave activity in the TTL varies as a function of latitude, longitude, and distance from convection; (2) how waves actually cause a cloud to form, and (3) the amplitudes of the very small scale gravity waves that affect the ice crystal size distributions, and how these amplitudes vary over large regional scales.

Science questions:

Q1a. What are the formation processes of TTL cirrus and how effectively do they dehydrate air entering the stratosphere? How are these likely to change in a changing climate?

Q1b. How do gravity waves, Kelvin waves, and other equatorial waves regulate clouds and dehydration in the TTL?

Measurement Requirements

Addressing these questions will require measurements of the sizes and number concentrations of ice crystals spanning the size range from ~1 m to ~1000 m. Sufficiently accurate determination of relative humidity will require water vapor measurements with ~10% accuracy under very dry conditions (water vapor mixing ratios as low as 1.5 ppmv) and temperature measurements with an accuracy of about 0.3 K. Ice crystal habit (shape) measurements will also provide important information about formation mechanisms. Long-range measurements along streamlines that pass through cold tropopause regions will reveal (for the first time) the conditions under which TTL cirrus form, how the clouds evolve, and their impact on water vapor concentration.

Extended duration aircraft measurements are required to characterize large regional variations in mesoscale gravity wave characteristics (Alexander et al., 2000), as well as horizontally extensive equatorial waves and their relationships to convection. Important components of the wave spectrum have vertical scales that are difficult to resolve with satellite measurements. Characterizing these waves and their effects on clouds will require the following measurements: (1) temperature, horizontal winds, and vertical winds; (2) vertical temperature profiles along the flight track; (3) water vapor; and (4) ice crystal habit and size distribution.

The proposed measurements will greatly improve our understanding of TTL cirrus microphysical properties, their interactions with waves, and their impact on TTL water vapor concentration. Process models for understanding particular observed cloud systems. Global models will be required to link the process knowledge to climate effects. Satellite observations (e.g., CALIPSO) will be required to evalute the simulations of TTL cirrus throughout the tropics. We anticipate that this project will lead to improved representation of TTL cirrus in climate models and improved ability to predict climate feedbacks associated with TTL cirrus and stratospheric humidity.

1.2.2. TTL Temperature Structure

The formation of TTL cirrus and control of the humidity of air entering the stratosphere are ultimately determined by tropopause temperatures. Large-scale temperature decreases with height in the tropics from the surface to the cold point tropopause (near 17 km, with temperatures near or below 200 K), followed by an increase with altitude in the stratosphere above. The temperature lapse rate in the troposphere up to the altitude of frequent deep convection (~12-14 km) results from radiative-convective balance. A small fraction of deep convection reaches above 14 km, infrequently extending up to or across the tropopause. A balance of radiation and dynamics determines the thermal structure above 14 km; the combined influences of cooling from carbon dioxide, heating from ozone and dynamically-forced large-scale upwelling (the BD circulation) results in a temperature minimum near 17 km, followed by temperature increases with height in the stratosphere (8) (Thuburn and Craig, 2000). The BD circulation is driven by wave breaking and momentum deposition deep in the stratosphere (Haynes and McIntyre, 19xx). However, the role of tropical waves in driving the Brewer-Dobson circulation is poorly understood (Kerr-Munslow and Norton, 2008). Our understanding of the properties of waves propagating into the tropical stratosphere is insufficient for the development of parameterizations of wave effects in global models that would permit confidence in predictions of feedback effects in a changing climate.

There is a high level of transient temperature variability within the TTL, linked to a broad spectrum of waves forced by transient convection (Bergman and Salby, 1994) plus fluctuations in the Brewer-Dobson upwelling. Much of this variability is difficult to observe with satellite because of relatively short vertical scales and transient variability. Cirrus clouds themselves may also alter the thermal structure in the TTL (9) (Hartman et al 2001).

One regularly observed mode of thermal variability is associated with planetary-scale Kelvin waves, which are eastward-propagating waves with periods 4-20 days (10) (Randel and Wu, 2005). There is a strong annual cycle in temperatures near and above the cold point



(but not below), related to an annual variation in the strength of the Brewer-Dobson upwelling (with strongest upwelling and coldest temperatures during boreal winter). This annual variation in cold point temperatures is reflected as a strong annual cycle in stratospheric water vapor, although the details of dehydration near the tropopause (and relations to clouds) are uncertain. There are also interannual variations in the TTL associated with the El Nino Southern Oscillation (ENSO) and the stratospheric Quasi-Biennial Oscillation (QBO) (Randel at al., 2000), plus an apparent drop in temperature in 2001 that resulted in a correspon Rosenlof and Reid (2008) showed a correlation with sea surface temperatures, which suggests a potentially important connection to climate changes. Possible mechanisms include changes in the depth of convection and changes in the waves driving the Brewer-Dobson ascent. ding decrease in stratospheric water vapor (11) (Randel at al., 2006). The tropopause temperatures have remained anomalously cold, and the stratosphere anomalously dry since the 2001 drop, and the underlying reason for the 2001 shift is unknown. Characterizing small scale temperature fluctuations in the TTL and linking them to convective and planetary wave forcing is critical for understanding the processes driving variations in clouds (and hence water vapor and radiation) in the TTL as well as for understanding the control of the TTL thermal structure itself.

Science questions:

Q2a. What roles do tropical waves play in the maintenance of and variability in tropical upwelling within the stratospheric transport circulation?

Q2b. How might the TTL thermal structure be altered in a changing climate, and what are the potential feedback effects?


Current satellites can only resolve tropical atmospheric waves with wavelengths longer than about 6000 km (Alexander et al 2008) , whereas conventional (manned) aircraft are best for mesoscale waves (24) (a few 100 km – Wang et al 2006). Additional measurements are required to fill the gap between these scales where there is considerable wave activity. Measurements of temperatures, winds, and vertical temperature profiles over distances of at least 4000-5000 km are required. The waves that drive circulations in the TTL will typically have periods of a few days, and are driven by the lower frequency component of convective systems. The equatorial region is favored for the upward propagation of such low frequency waves (Longuet-Higgins, 194X). Since many of these wave modes have nodes at the equator, flights just off the equator (5-10 degrees) will be required. Long flight legs (at least 5000 km) along a latitude circle with short interruptions for vertical profiling are required to ascertain the amplitudes and structures of these waves. Ideally, these flight legs should go as far into the Western Pacific as possible, since that region is the generation region for many of the waves of interest. Measurement campaigns during multiple seasons are required for investigation of seasonal variability. The information provided by airborne measurements will need to be combined with global information about longer-period waves from satellites and global high-resolution process models. In particular, TRMM satellite measurements of precipitation will be used as initial conditions for wave models that will be validated with the ATTREX measurements and satellite temperature measurements from AIRS and MLS. The combined airborne and satellite datasets will be used to improve parameterizations of waves in global models and to improve predictions of changes in the TTL thermal structure in a changing climate.

1.2.3. TTL Radiation and Transport

Only in the tropics are mean verical velocities positive at the tropopause, implying that most of the tropospheric air that eneters the stratospheric “overworld” passes upward through the TTL (Figure 1-1). As illustrated in Figure 1-2, many physical mechanisms affect TTL transport and composition: slow, large scale ascent; episodic, rapid transport in deep convection; vertical mixing due to turbulence, and lateral, quasi-isentropic mixing with “old” air from midlatitude stratosphere (air that has not had tropospheric influence for an extended period). The interplay of these mechanisms can have important chemical and climatic effects. Deep penetration of convection, for example, can inject water vapor and short-lived reactive species and increase cloudiness in the TTL, affecting ozone depletion (Solomon at al., 1986) and surface temperature. However, the effects of convection are very uncertain—even the sign of convective influence on relative humidity is unclear, since convection can modulate the thermal structure of the TTL (Rosenlof and Reid, 2008). Within the TTL, photochemical reactions and competing physical processes are important for chemical species whose lifetime is comparable to the ~2 months that it takes for slow ascent to traverse the TTL. Short-lived precursors of reactive halogen radicals are more likely to reach the stratosphere if there is significant rapid and deep convective transport (13) (“extreme” convection in Figure 1-2) and the same convective processes may facilitate removal of reactive inorganic species. Extensive in-mixing of air from midlatitudes will increase the age of the air in the TTL and also reduce the input of short-lived halogen precursors into the stratosphere. Such in-mixing can also reduce TTL relative humidity and cloud formation (12) (Fujiwara et al., 2009).

TTL transport mechanism are poorly understood, both in terms of mean rates and variations with longitude and season, reflecting limited observations. Slow ascent rates at the tropopause vary by a factor of two from boreal summer to winter (Yang at al., 2009). In the TTL, latent heat is a small term in the energy budget, and adiabatic cooling(heating) driven by adiabatic ascent(descent) is approximately balanced by radiative heating(cooling). Therefore, calculations or measurements of radiative heating can be used to diagnose large-



scale TTL vertical transport. Such calculations show that, under clear-sky conditions, ascent in upper part of the TTL (above ~15.5 km) is balanced by radiative heating (4) (e.g., Gettelman et al., 2004). The rate of vertical transport through the TTL and lower stratosphere has been estimated from observations of the water vapor “tape recorder” (Mote et al., 1996; Niwano et al., 2003; Schoeberl et al., 2008), from observations of the CO2 gradient in the TTL (5) (Park et al., 2007), and from radiative transfer calculations (Rosenlof et al., 1997).

Recently work shows that cirrus within the TTL play an important role in the local thermal budget. Radiative transfer calculations have shown that thin cirrus in the TTL can experience radiative heating of a few K/day (Jensen et al., 1996; McFarquhar et al., 2000; Comstock et al., 2002). Using measurements from spaceborne lidar to provide information about TTL cloud distributions, radiative transfer calculations show that when clouds are included, the tropical mean radiative heating rate is positive above about ~13-14 km (Corti et al., 2006; Yang et al., 2009). These results have important implications for vertical transport through the TTL. In the clear-sky view, with large-scale ascent only above 15.5 km, outflow from typical tropical convection (~1213 km) will simply descend back down into the middle troposphere, and only extreme convective events detraining above 15.5 km would affect the composition of air entering the stratosphere. However, based on the calculations including clouds, it appears that large-scale ascent may be occurring in general above an altitude (~13 km) that is near the main convective outflow level (Figure 1-2).

There are strong longitudinal asymmetries in TTL cirrus associated with the variations in convection and temperature. In boreal summer, for example, strong ascent occurs over the Indian Ocean and inside the monsoon anticyclone, with descent in much of the Pacific (Yang et al 2009, Park et al., 2007). In boreal winter, the strongest ascent is over the western Pacific (14) (Fueglistaler at al., 2005), with descent occurring below 14 km over much of the tropics. Convection is also zonally and seasonally asymmetric. Mid-oceanic convergent zones have convective tops that rarely exceed 13.5 km, while a significant percentage of western Pacific boreal winter convection (~3%) reaches the tropopause.

TTL cirrus are also directly important for the Earth’s radiation budget, and hence climate in general. Halladay and Stephens (2009) (7) recently identified a class of optically thin cirrus that were detected by the CALIPSO lidar measurements but not detected by the CloudSat radar measurements. These clouds occurred almost exclusively in the TTL. The estimated effects of these clouds on the tropical average top-of-the-atmosphere radiative fluxes were several W m-2 warming in the infrared, a few W m-2 cooling in the solar, and a few W m-2 warming for the net flux. The ultimate role of TTL cirrus in future climate change involves feedback effects. A robust response of climate models to greenhouse-gas increases is a strengthening of the Brewer-Dobson circulation. Increasing TTL ascent rates will likely increase the occurrence of in situ cirrus formation, therby increasing radiative forcing.

Exchange between the TTL and the extratropical lower stratosphere also shows large zonal asymmetries. In the boreal winter season, the subtropical jet provides a substantial barrier to transfer between the midlatitude lower stratosphere and the TTL below the tropopause (15) (Haynes and Shuckburgh, 2000). In the boreal summer, however, the Asian monsoon anticyclone produces stationary zonal asymmetries in the large scale flow, leading to extensive Rossby Wave Breaking downstream in the Pacific (Postel and Hitchman, 1999), and subsequent inflow of midlatitude air into the tropics. Vertical mixing due to turbulence outside of convective zones has typically been ignored, but there is direct evidence of turbulent mixing in connection with Kelvin waves (16) (Fujiwara et al 2003), and indirect evidence that such mixing occurs on the equatorward side of the subtropical jet (Konopka at al., 2007).

Science questions:

Q3a. What is the relative importance of typical convection detraining at ~13 km versus extreme convection detraining above 15 km for the humidity and composition of air entering the stratosphere?

Q3b. What is the effect of TTL cirrus on the Earth’s radiation budget and TTL radiative heating?

Q3c. What are the mechanisms for transport from the midlatitudes, and how important are they?


Most of the tracers used to diagnose TTL transport processes (e.g., CO2, CO and SF6) either are not measured by satellites or are measured with insufficient vertical resolution. Recent aircraft field experiments using conventional aircraft (e.g., the Costa Rica Aura Validation Experiment (CRAVE) and the Tropical Composition, Cloud, and Climate Coupling (TC4) missions) have provided tracer measurements over very limited regional domains and time periods, which yielded reasonable estimates of upward transfer rates (17) (Schoeberl at al., 2008; Aschmann et al 2009). However, the large longitudinal and seasonal variations in TTL transport processes imply that these observations provide a limited view of global transport through the TTL. What is required are measurements that: (1) span both the regions of large scale ascent in the TTL and large scale descent and (2) are able to sample the downstream output of most classes of convection (“typical” and “extreme” in Figure 1-1). Seasonal variation is also important, both because ascent is so much weaker in the summer, and because of the much larger zonal asymmetry (and potential midlatitude in-mixing) in the summer. This proposal is intended to address the crtitical need for tracer measurements that are both fine grained (obtainable only by aircraft) and sustained at large regional scales (obtainable only by a Global Hawk mission profile).


Table 1-1. Very short lived brominated species in the troposphere*

Species Trop. Lifetime (days)

Source ** Estimated mean mixing ratios (pptv) in the tropics

Estimated global source [Gg(Br)y-1)]

Marine boundary layer Upper troposphere

CHBr3

CH2

Br2

CHBr2

Cl

CH2

BrCl

CHBrCl2

26

120

70

150

78

N

N

N, A

N

N, A

1.6 (max> 40)

1.1

0.3

0.5

0.3

0.4

0.9

0.1

0.3

0.1

200-800

30-240

10-50

* The dominant brominated species in the troposphere (≈ 25% of Br) are longer-lived CH3

Br and Halons and are relatively uniformly distributed

(WMO, 2007)

** N: Natural (largely oceanic); A: Anthropogenic


Bucholtz et al. (2009) (23) recently showed that the heating rate in optically thin TTL cirrus can be measured with high-altitude aircraft (in this case the ER-2) observations of zenith and nadir radiative fluxes above and below the clouds and as the aircraft transits through the clouds. Such measurements of extended clouds under a variety of conditions, along with the microphysical measurements described above, are required for evaluation and improvement of radiative transfer calculations. Radiative transfer calculations using climatological cloud information throughout the tropics (provided by satellites) are required to assess the overal impact of TTL cirrus on the radiation budget. The measurements of TTL cirrus microphysical properties and radiative effects will improve the accuracy of the global calculations.

Chemical transport models including the observed tracers (17) (e.g., Aschmann et al., 2009) will be required to evaluate transport mechanisms and their representation in global models, and GCMs (with improved representations of transport) will be required to predict future changes in TTL transport and associated feedbacks.

1.2.4. TTL Chemistry

The TTL is important for setting the chemical boundary conditions of the stratosphere. This is particularly true for very short-lived substances (VSLS) whose lifetimes are typically less than six months, comparable to or shorter than the transit time through the TTL (18) (19) (Fueglistaler et al., 2004; WMO 2007). The predominant pathways for VSLS transport into the UT/TTL are likely to be in tropical convection regions, co-located with high emissions. An important group in this category is made up of brominated organics which are principally of oceanic origin with sources dominated by coastal areas and tropics (19 p. Table 1) (Table 1; WMO, 2007).

In the traditional view, the bromine budget in the stratosphere is principally controlled by long-lived species such as CH3Br and Halons.

Bromine monoxide (BrO) measurements in the lower stratosphere have indicated that brominated VSLS probably contribute significantly (≈25%) to the Br budget in this region (e.g., Ko et al., 1997; Pfeilsticker et al., 2000). Inclusion of this bromine in models results in larger ozone destruction in the lower stratosphere via interactions of this bromine with anthropogenic chlorine (BrO + ClO) and HOx (20) (Ko et al., 1997; Dvortsov et al., 1999; Pfeilsticker et al., 2000; Salawitch et al., 2005). Balloon and satellite data also suggest a global abundance of 0 to 3 ppt of BrO distributed throughout the troposphere (21) (Harder et al., 1998; Müller et al., 2002; Richter et al., 2002; Platt and Hönninger, 2003; Dorf et al., 2006 and 2008). Several satellites (OMI, SCIAMACHY) have deduced residuals of BrO in the lower troposphere widely believed to be involved in tropospheric O3 destruction processes.

Uncertainty in the reactive bromine role is due to variable sources and limited understanding of VSLS transport through the TTL. The role of convection in redistributing surface emissions and regulating transport of VSLS to the TTL region is uncertain (13) (22) (Gettelman et al 2009; Sinnhuber and Folkins, 2006). Better constraining the distribution of VSLS in the TTL is critical for understanding these pathways and their impact on stratospheric ozone.

The large discrepancy between the measured and modeled burden of stratospheric BrO has been the source of much debate in the atmospheric chemistry community and is presently poorly understood. BrO and precursor measurements from the tropical TTL region are extremely

sparse and in many cases nonexistent (e.g., Laube et al., 2008).

With we will focus our efforts in this investigation on bromine chemistry.

Science Questions:



Q4a. What is the vertical distribution of BrO and short lived halogen compounds in the TTL and how does it vary seasonally and geographically?

Q4b. Are TTL O3

and halogen observations consistent with photochemical theoretical models?


The primary gap in our understanding of TTL chemistry that we propose to address is the budget of brominated species. Highly sensitive BrO measurements (sensitivity 1 ppt; accuracy ±10%) are required in addition to measurements of very short-lived brominated species (i.e., CHBr3, CH2Br2, and CHBr2Cl) (sensitivity 0.5 ppt; accuracy ±5%). These measurements are required over broad regions in the tropics as well as in different seasons. Multiple tracers of convective influence will also be required to understand the relationship between brominated species concentrations and transport pathways. We will also need to assemble a global database of organic and inorganic

brominated species based on previously available measurements in the troposphere and the stratosphere. Analysis and interpretation of data from this experiment will require

integration of all acquired and assembled data with models of chemistry and transport (13) (17) (e. g. Gettleman et al., 2009; Aschmann et al., 2009).



2.0. Science Implementation

2.1. Science Investigation Concept

To answer the 9 science questions posed in section 1, we propose an instrumented Global Hawk aircraft in four separate phases over 2 years. These phases span the seasonal cycle of variation in the basic TTL environment. The physical processes operate on a broad range of scales, requiring the capability to examine variations from 1 to several 1000 km in size. An example of this is science question 1b, involving the impact of waves on clouds and the TTL thermal structure. Small scale gravity waves (1 – 10 km, time scales of minutes) affect particle size distributions in thin cirrus clouds (Jensen et al, 2009), which affects their ability to dehydrate the tropopause region. Large scale (5000-10000 km, seasonal time scales) variations in relative humidity create favorable regions for cloud formation. Intermediate scale waves (100-5000 km, multi-day time scales) induce periods of cold temperatures that allow ice nucleation to take place. Only a very long-range aircraft can sample variability across all of these scales. The Global Hawk has an operating radius of ~8500km, 2.5 times that of manned high altitude aircraft (ER-2, see range rings in Figure 2-1). This and the Global Hawk’s typical altitude of 13.8-20 km make it an an essential platform for this investigation.

2.1.1 Operational Time Line

The mission starts June 2010, with a kickoff science team meeting in July. The next twelve months will be devoted to: (1) adapting and integrating the instruments to the Global Hawk; and (2) adapting existing flight planning, forecasting, data analysis, and modeling tools to the mission.

Test flights (Phase 1 of four) based at NASA/DFRC will be conducted in summer 2011. This phase will include at least one full-length science flight, two examples of which are shown in Figure 2-1a, and further discussed in 2.1.2. The first full science phase (Phase 2) takes place in January, 2012, when the Global Hawk will be based in Guam for 32 days to make observations during boreal winter. 32 days is sufficient to

span most of the 40-50 day Madden-Julian oscillation in large scale tropical convection. The tropical tropopause is seasonally at its coldest during this period, and Guam is near the coldest temperatures, the lowest water vapor (Figure 2-1b), the highest incidence of observed TTL clouds (Figure 1-3), and the region with the largest mean ascent rate. For each main science phase there will be 200 flight hours and 8 science flights: 2 transit missions to and from NASA/DFRC and 6 science flights based in Guam. The average length of these flights will be 25 hours, with no flight exceeding 30 hours.


Figure 2-1. Sample Global Hawk flight profiles for the four phases of GMT2. The colored

profiles represent different flight plans as described in the text. All of the flights are of 28

hours duration, except for the magenta flights in b and d, which are 24 hours. Solid and

dotted black lines represent maximum range rings for the Global Hawk and ER-2 aircraft,

respectively.


Phase 3, based in Hawaii, will take place in fall 2012, during the transition from boreal summer to winter. Phase 4 will examine the boreal summer season, which differs fundamentally from winter (Phase 2), having warmer temperatures, higher water vapor (Figure 2-1d), slower mean TTL ascent rates, and stronger mass exchange with midlatitudes due to the zonally asymmetric monsoon circulation. This phase will occur in July, 2013 with the Global Hawk based in Darwin, Australia. From Darwin, the Global Hawk will be able to examine the nearby summer cold pool, as well as the Asian monsoon anticyclone, believed to be a region of upward motion into the stratosphere (Park et al, 2007).

Data analysis will start after the first science flight of Phase 1 (summer, 2011). The phases are 6-9 months

apart, so there is ample time (almost 2 years from Phase 4 to mission end) for data analysis and modeling. This flexible schedule can deal with delays in aircraft readiness by moving Phase 2 to winter 2014, still leaving 1.3 years for analysis.

2.1.2 Observing Profile

The Global Hawk will conduct 4 basic types of flight profiles during the four phases, as shown by the four different colored flight tracks in Figures 2-1(a-d). The importance of each of these flight profiles to the 9 science questions outlined in section 1 is listed in Table 2-1.

The most important Flight Profile is FP1 (red lines in Figure 2-1) a longitudinal survey at TTL altitudes at least 60 degrees in length within 15 degrees of the equator. It covers regions of the TTL with different convective, water vapor and slow ascent characteristics, providing statistics to address all the science questions. The constant latitude course is needed to perform spectral analysis on equatorial waves whose scales are between those measured by satellites and by conventional high altitude aircraft (questions 1b and 2a) . Transit legs from Dryden to Guam or Darwin (Figure 2-1b, dotted red) are particularly valuable for this purpose, since they can cover 120 degrees of longitude, a third of the globe. FP1, whose typical cruise altitude will be below the tropopause, includes along-track vertical profiling (Figure 2-2a) to capture information over the full depth of the TTL. Meteorological forecasts will determine the placement of these profiles. For example, the aircraft may profile a region downstream of a convective system.

FP2 (green in Figure 2-1), a latitudinal survey, addresses transport from midlatitudes, and the large scale distribution of BrO and other short-lived halogen compounds. FP3 (blue in Figure 2-1) is a TTL survey targeted to the Indian Ocean region during Phases 2 and 4. During boreal winter (Phase 2), the Indian Ocean TTL is considerably moister than the Pacific region (Figure 2-1b) and upward motion is also weaker. During boreal summer, a strong anticyclone forms over the north Indian region, leading to a maximum in slow ascent (Figure 2-1d). Sampling in these regions is important for understanding upward transport (question 3a) and the distribution of BrO and short-lived halogens (question 4a). As for FP1, FP2 and FP3 will both include along-track vertical profiling (Figure 2-2a). TTL cirrus sampling will also occur during these flights.

FP4 (magenta in Figure 2-1) investigates the evolution of water vapor and cloud along a trajectory as it enters and exits the major TTL cold pools in the western Pacific. These regions are slightly north of the equator in boreal winter, and on or south of it in boreal summer. As part of FP4, the aircraft will do a cirrus cloud passage vertical maneuver (Figure 2-2b) when a cloud is detected underneath the aircraft. The aircraft will descend through the cirrus cloud to measure radiative fluxes and heating rates, and then return to cloud altitude in order to make measurements of water vapor, temperature, cloud particles, and winds approximately along air parcel trajectories. Most of FP4 will be spent at the cloud altitude near the cold point tropopause. These flights will (for the first time) provide information about the supersaturations required for cold TTL cirrus and the irreversible dehydration of TTL air by the clouds.

2.1.3 Flight Planning and Forecasting


Figure 2-2. Typical vertical profiles along the flight track: (a) Along-track vertical

profiling for FP1, FP2, and FP3, (b) Vertical profiles for FP4.


The NASA Goddard flight planning software will be used for proposing flight plans and requesting in-flight course changes. Most NASA field campaigns supported by the Upper Atmosphere Research Program since 1993 have used this software, which has recently been customized for the Global Hawk for GLOPAC. This software enables the scientist to efficiently target the aircraft for maximum science return while remaining within the aircraft’s operating parameters (i.e., range, speed, restricted flight areas). The software permits overlaying aircraft courses and altitude profiles on meteorological fields (i.e., temperature, winds) from global forecast models. Thus, we can either target (cold temperatures) or avoid (convection) certain forecast features.

Meteorological forecasting is a key part of flight planning. We will use global meteorological forecast models (NCEP Global Forecast System and NASA GSFC GEOS-5) to produce graphical products (available to the science team via a web site) depicting the coldest temperatures (where cirrus clouds would form), the position of the subtropical jet (to sample midlatitude air), and regions of wave breaking (where midlatitude air enters the tropics). Other tools include trajectory-based forecasts of convective influence (for vertical profiling – see above), forecast tracer distributions from chemical transport models (e.g., CAM, WACCM, GEOS-5), and quicklook satellite products (CALIPSO for clouds and MLS for water vapor).

2.2. Science Data

2.2.1 Science Traceability

The Science Traceability Matrix (Table 2-1) shows the measurements, instrument requirements, and investigation requirements (flight profiles, links with satellite data, modeling) needed to answer the 9 science questions from section 1. The left column shows the main science objectives and respective section numbers. The discussion here is brief, with details in section 1.

Flight profile 4 (magenta in Figure 2-1) addresses Q1a (TTL cirrus formation) by exploring the cold regions where TTL cirrus are plentiful. We will use: (1) process models to understand the microphysics implied by measured ice crystal size distributions and relative humidities; (2) trajectory-based microphysical models (Jensen and Pfister, 2004) to evaluate the implications for global TTL water and clouds (as measured by satellites); and (3) global models to evaluate climatic effects. Flight profiles 1 and 3 address Q1b (waves) through extended surveys of TTL meteorological variables. Measured wave distributions input into trajectory-based or 3-D global microphysical models help us understand wave effects on TTL water and clouds. Flight Profile 1’s extended longitudinal surveys of meteorological variables coupled with spectral analysis, satellite data, and wave models improve our understanding of how tropical waves drive the TTL slow ascent and thermal structure (Q2a – Figure 1-2). The improved wave parameterizations will allow global climate models to more confidently forecast TTL thermal structure changes (Q2b).

We address the issues of upward (Q3a) and midlatitude (Q3c) transport with extended surveys within the TTL (Flight Profiles 1 and 3) and into midlatitudes (Flight Profile 2). The measurement requirement for these questions is ozone and a suite of tropospheric tracers (Table 2-1) with a range of lifetimes both longer and shorter than a few months (the transit time through the TTL via slow ascent). Other useful tracers have a seasonal variation in the underlying troposphere (CO2) or a strong secular trend (SF6). For upward transfer, weak convective detrainment within the TTL yields low abundances of short-lived (1-2 weeks) tracers, while stronger detrainment enhances them. Long-lived tracers decay slowly and are relatively unaffected by convection. Comparisons of measurements with results from 1-D and 3-D Chemical Transport Models (CTMs) test convective parameterizations, thus answering Q3a. Time scales of transfer from midlatitudes are longer, so we will use measurements of SF6, CO2, and ozone in 3-D CTMs to answer Q3c. Solar occultation measurements from ACE (e.g., CO, C2H6), though infrequent in the tropics, have the vertical resolution to diagnose transport in the TTL. ACE and aircraft data comparisons yield information about interannual variability in upward transport. Measurements of water vapor, temperature, ozone, ice crystals, and broadband radiative fluxes made during the penetrations of TTL cirrus (Figure 2-2b, Flight Profile 4) will address the impact of these clouds on the radiation budget (Q3b). We will use the measurements for radiative transfer closure calculations, and apply the results to parameterizations in global climate models.

ATTREX provides first order information about the TTL BrO and short-lived halogen distributions (Q4a). Comparison of the measurements with 3-D CTM results will reveal the gaps in our understanding of the chemical dynamics of these compounds (Q4b).

2.2.2 Data Management Plan

Each instrument measuring the above-described parameters is the responsibility of an individual investigator, who will reduce and validate his or her own measurements. This is straightforward, since versions of all the instruments have flown previously on high altitude aircraft (see section 3 for TRL levels). The first (of three) stages of data availability is quick-look data transmitted to ground stations in real time. The science team will use these data to recommend changes in aircraft course and altitude to enhance mission science. The following are needed in real time: cloud vertical profile information, ozone, water vapor, winds, temperature, temperature profile, tropopause altitude, ice crystal number density, CO, and CO2. The second stage is preliminary digital data available in an online archive maintained by the Ames Earth Sciences Project Office (ESPO) within 48 hours of the end of each flight (excepting quantities



requiring either laboratory analysis or complex retrievals). All except the cloud profile measurements will be in the “Gaines-Hipskind” ascii data format, used for in-situ aircraft data by NASA’s Upper Atmosphere Research Program (UARP) since 1987. The cloud profile information will be in a format (ascii, hdf, or netcdf) readable by standard software. Final data (stage 3) for each of the four experimental phases will be available to the science team within 9 months of the end of each phase, with public release 3 months later. Auxiliary data along the aircraft flight track (winds, temperature, EPV, and water vapor from meteorological analyses; trajectories from the aircraft track; information about convection upstream of points along the aircraft track) will be part of the final and preliminary datasets. As for all UARP airborned missions since 1987, espoarchive.nasa.gov, managed by ESPO will be the final electronic archive for all of these data.

2.3. Science Team

The science team (Table 2-2) includes the PI, a deputy PI, four platform scientists, 3 meteorologists, 7 modeling and analysis scientists, and 12 instrument investigators. Several team members have overlapping responsibilities. The PI, Dr. Eric Jensen, has extensive experience with NASA aircraft missions; he has overall responsibility for all aspects of the mission. The deputy PI is also Chief Meteorologist, part of a team of 3 with extensive experience in NASA field campaigns. The four platform scientists will develop flight plans and interact with the instrument investigators. They have extensive past experience in leading major NASA airborne deployments. Global Hawk will be aloft for upwards of 30 hours, and science and meteorological input will be required during the entire period, requiring 3 shifts of decision makers. Drs. Alexander, Bardeen, Gettelman, and Randel will do modeling and will play an advisory role during the aircraft field phases, providing input for flight planning based on their expertise on atmospheric structure and data analysis techniques. All science team members will be involved in data analysis.

Past experience has shown that, when making precise measurements of compounds that occur in the parts-per-trillion to parts-per-million range, assigning responsibility for each measurement to a particular instrument PI is the best way to insure the measurement integrity. Each of the 12 instrument team leaders is responsible for one or more of the measurements needed to answer the science questions as indicated in the Tables 2-1a and 2-1b above.




Table 2-1. Science Traceability Matrix

Science Objectives Scientific Measurement Requirements Instrument Functional Requirements Investigation Functional Requirements

1.1.2.1 TTL Cirrus and Control of

Stratospheric Humidity (Q1a, Q1b)

Vertical Profiles of aerosol and cloud backscatter

Water Vapor

Ice Crystal Size distributions and Ice Crystal Habits

Temperature

Temperature Profiles (Q1b)

Winds

10-5 backscatter ratio sensitivity, 200 meter horizontal resolution, 30 meter vertical resolution

10% accuracy, 200 meter horizontal resolution

Size distributions at 1 km resolution; size detection from .5 microns to 500 microns

200 meter horizontal resolution, .3K accuracy

0.1 km vertical resolution, 5 km horizontal resolution, 1K accuracy at flight level

200 meter horizontal resolution., .05 meter per second precision.

Flight Profile 4, Flight Profile 1 (Q1b), Flight Profile 3 (Q1b, desirable)

Microphysical process models; Trajectory-based microphysical global models; Global climate models.

CALIPSO

1.1.2.2 TTL Temperature Structure (Q2a,

Q2b)

Winds, Temperature, and Temperature Profiles

Same as for 1.1.2.1 Flight Profile 1

TRMM, AIRS, MLS, and modeling

1.1.2.3 TTL Radiation and Transport (Q3a,

Q3b, Q3c)

Ozone

Tacers with lifetimes of 1 week to months (Q3a,Q3c)

Methane, CO2 (Q3a,Q3c)

N2O, SF6 (Q3a,Q3c)

CO (Q3a, Q3c)

Broadband radiative fluxes and flux divergence (Q3b)

Water Vapor

Temperature

10 ppbv accuracy, 200 meter horizontal resolution

0.5 km vertical resolution, 2 degree horizontal resolution, precision of .05 times the expected variation between the upper troposphere and lower stratosphere.

2 km horizontal resolution with 1% precision, 5% accuracy for methane and 0.5 ppmv accuracy and .1 ppmv precision for CO2

20 km horizontal resolution and 1% precision

30 km resolution and 10% precision

1% precision across the visible and IR spectrum.

10% accuracy, 200 meter horizontal resolution

Same as 1.1.2.1

Flight Profiles 1, 2, 3 (very desirable for Q3a), and 4 (Q3b)

1-D chemical transport models (Q3a,Q3c), Chemical Transport Models (Q3a, Q3c), radiative transfer calculations (Q3b)

1.1.2.4 TTL Chemistry (Q4a, Q4b) BrO

Short-lived halogen compounds

1 pptv sensitivity, 5% precision, 10% accuracy

1 pptv sensitivity, 5% precision, 10% accuracy,.

Flight Profiles 1 and 2 critical; Flight Profile 3 desirable.

Modeling (Q4b)

Table 2-2. Science Team

Name/Organization Mission Role Pertinent Background

Dr. Eric Jensen,

NASA/ARC

Principal Investigator, process microphysical modeling, global microphysical trajectory modeling TC4 Flight Scientist

PI, CRYSTAL/FACE

Dr. Leonhard Pfister

NASA/ARC

Deputy PI, Chief Meteorologist, global microphysical trajectory modeling, Co-Chief Meteorologist, TC4, GLOPAC

Dr. David Fahey

NOAA ERL

Platform Scientist, aircraft data analysis Co-PI, GLOPAC

Dr. Paul Newman

NASA/GSFC

Platform Scientist, 3-D Chemical Transport Modeling, Satellite Data Analysis Co-PI, GLOPAC,

TC4 Flight Scientist

Dr. Hanwant B. Singh

NASA/ARC

Platform Scientist, Chemistry Analysis ARCTAS and INTEX mission scientist

Dr. Owen B. Toon

University of Colorado

Platform Scientist, 3-D microphysical modeling TC4 Mission Scientist

Co-PI, CRYSTAL/FACE

Dr. M. J. Alexander

NWRA/CORA

Wave analysis and wave modeling, satellite data analysis AIRS, Aura, HIRDLS, CAMEX4, CRYSTAL/FACE teams

Dr. Charles Bardeen

NCAR

Meteorologist, 3-D microphysical and climate modeling Meteorologist, TC4

Dr. Andrew Gettelman

NCAR

1-D and 3-D Chemical Transport Modeling, Climate Modeling Climate Modeler

Dr. William Randel

NCAR

Satellite Data Analysis, Climate Modeling START and HIPPO science teams

Dr. Henry Selkirk

GEST/UMBC

Meteorologist, 3-D Chemical Transport Modeling, Co-Chief Meteorologist TC-4

Dr. Steven Wofsy

Harvard University

Multiple Trace Gas Measurements, 1-D Chemical Transport Modeling Trace Gas Measurement PI, HIPPO

Dr. Elliot Atlas

University of Miami

Multiple Trace Gas Measurements Trace Gas Instrument PI, TC4

Mr. T. P. Bui

NASA/ARC

Meteorological Measurements Meteorological Measurements PI, TC4

Dr. Glenn Diskin

NASA/LARC

Water Vapor Measurements Water Vapor PI, ARCTAS and TC4

Dr. James Elkins

NOAA ERL

Multiple Trace Gas Measurements Trace Gas Instrument PI, GLOPAC

Dr. Ru-Shan Gao,

NOAA/ERL

Ozone Measurements Ozone Measurements PI, GLOPAC

Dr. Robert Herman

NASA/JPL

Water Vapor Measurements Water Vapor PI, GLOPAC and TC4

Dr. Paul Lawson

SPEC, Incorporated

Ice Crystal size and habit Measurements Cloud measurement PI, TC4

Dr. Matthew McGill

NASA/GSFC

Cloud and Aerosol Backscatter Cloud and Aerosol Backscatter PI, TC4

Dr. M. J. Mahoney

NASA/JPL

Vertical Temperature Profile Measurements, Vertical Temperature Profile PI, GLOPAC

Dr. Klaus Pfeilsticker

U Heidelberg, Germany

BrO DOAS measurements Ozone Assessment Co-Author, Full Professor, U Heidelberg

Dr. Peter Pielewskie


Broadband Radiative Fluxes Radiative flux measurements PI, TC4

Dr. Jochen Peter Stutz

UCLA

BrO DOAS measurements PI 20 yrs DOAS experience;SHARP

GSHOX,TEXAQS field progs



Figure 3-1. Global Hawk Aircraft


3.0. Investigation Implemenation

3.1. Measurement Platform System Capabilities

The RQ-4A Global Hawk air vehicle is a mid-wing, high-altitude aircraft capable of operating at altitudes in excess of 60,000 feet. The vehicle is unmanned and typically operates as a fully autonomous vehicle using a comprehensive pre-loaded mission plan. As one of the largest unmanned aerial systems (UAS) in the world (e.g., the air vehicle has a wingspan slightly greater than a Boeing 737 aircraft), the NASA Global Hawk air vehicle provides the customer with an unprecedented long endurance flight capability through the troposphere into the lower regions of the stratosphere. The aircraft is powered by a single AE-3007H turbofan engine which generates 7500 lbs thrust at sea level. (Figure 3-1)

The Global Hawk aircraft has numerous existing payload compartments, and the

potential for adding wing pods. The air vehicle has the capacity to provide science payloads with substantial margins for payload mass, volume, and power in these payload spaces. Given the vehicle’s, altitude, range, and payload capabilities, it is well-suited for a meso-scale research mission of the TTL.

Two NASA Global Hawk aircraft (871 & 872) are based at the Dryden Flight Research Center. These two aircraft were manufactured under the original Defense Advanced Research Projects Agency (DARPA) Advanced Concept Technology Demonstration (ACTD) Program. Global Hawk 871 was the first Global Hawk aircraft manufactured and is a well-proven air vehicle that has flown more than 500 hours, including flights to and from Europe. Global Hawk 872 was the sixth air vehicle manufactured and has flown less than 200 hours. Table 3-1 summarizes the primary Global Hawk vehicle performance parameters.

3.1.1. Global Hawk Payload Capacity

As mentioned, the NASA Global Hawk has 14 payload zones with approximately 336 ft3 available for science use. Seven of these zones are environmentally conditioned pressurized compartments and the remaining seven compartments are non-pressurized and experience ambient temperature and pressure conditions during the flight.

One of the ATTREX instruments will require under-wing mounting. New pylon attachment mounts are fully funded and under development by NGC for DFRC. This pylon mounting arrangement will be used for the Hawkeye Sensor. A counter-weight pylon on the opposing wing shall be used to mount a reflectomer for use by the DHL instrument sensor.

A weight and Center of Gravity (CG) review has been conducted by the Global Hawk Payload Manager. The ATTREX instrument arrangement described below meets the CG requirements of the aircraft.


Table 3-1. Global Hawk Performance Summary

Parameter Value

Range (nm) 11,000

Payload (lbs) 1200

Altitude (ft) 65,000 max

Operational Altitude Range (ft) 40,000-65,000

Max Fuel Load (lbs) 15,000

Duration (hrs) 31

Speed (kts) 335

Power (KVA) 8.2

Min Runway Length (ft) 8000

Figure 3-2. ATTREX Instrument Arrangement on the Global Hawk


3.1.2. Ground Control Station (GCS)

At DFRC the Global Hawk GCS is a building-based capability located in the GH Operations Center (GHOC) in Building 4840. The GHOC consists of two adjacent rooms - the Flight Operations Room (FOR) and the Payload Operations Room (POR).

The FOR contains the GCS and five workstations for the command and control of the air vehicle, monitoring of the air vehicle systems, air traffic control coordination, mission direction, and GHOC operations. The POR contains the Ground Payload C3 System and fourteen workstations to support all payload-related and data display functions. The GPCS provides the ground-based integrated system associated with the aircraft's Airborne Payload C3 System (APCS). The GPCS provides global Iridium-based narrowband and Ku-Satcom wideband communications links, data servers, and the associated network for payload C2 and data handling.

The GPCS network architecture has been designed to be outside the DFRC firewall thereby allowing eased access for PI's to use their own computers to communicate directly with their instrument onboard the aircraft during a mission. PI communcation with their instruments is Ethernet based; UDP protocol over the Iridium links, and TCP/IP over the Ku-band links. The GPCS server architecture includes an outward-facing server for dissemination of selected real-time instrument data to any other computer.

3.1.3. Global Hawk Mobile Operations Facility (GHMOF)

A GMOF is being developed by the Global Hawk Project for use with remote deployments of the Global Hawk aircraft. The GHMOF is fully funded and currently under development by Dryden Flight Research Center and will provide in a shippable trailer the complete functions of the GHOC Flight Operations Room (FOR) capability including the full capabilities of the GCS and the line-of-sight and SatCom C2 links to the aircraft. The GHMOF is expected to be completed, and certified for flight by March of 2011.

Because the GHMOF will be providing a replica of the baseline GHOC GCS command, control, and communications architecture, it will be completely capable of not only launch and recovery operations of the GH aircraft at any remote site chosen for ATTREX deployments, but also full beyond-line-of-sight SatCom-based flight of a GH for the duration of the mission. This provides operational risk reduction in the event that the DFRC GCS is being used to fly the other NASA Global Hawk vehicle.

3.2. Instrumentation

3.2.1. Mission Instrument Summary

The proposed integrated ATTREX payload onboard the Global Hawk is shown in Figure 3-2.

Each instrument, with key perfromance data and associated GH payload zone location in summarized in Table 3-2.

Based on the payload location and requirements for each instrument, the Global Hawk has approximately XXX lbs of remaining payload weight (and volume), using XX% of total available power, and YY% of total data handling capacity. This margin will be held in reserve as a contingency for payload or integration weight increase, but may also be available for additional “piggy-back” instruments to be flown on the vehicle.


Figure 3-X. Cloud Physics Lidar (CPL)


3.2.2. Instrument Descriptions

3.2.2.1. Cloud Physics Lidar (CPL)

(McGill, GSFC)

The CPL is a multi-wavelength backscatter lidar originally built for use on the high altitude ER-2 aircraft and was first deployed in 2000. The CPL provides information to permit a comprehensive analysis of radiative and optical properties of cirrus and subvisual cirrus clouds. A duplicate CPL instrument has been constructed for use on the Global Hawk, and that instrument has been integrated and is currently awaiting first flights as part of the GloPac field campaign.

The CPL utilizes a high repetition rate, low pulse energy transmitter and photon-counting detectors. The CPL is designed specifically for three-wavelength operation (355, 532, and 1064 nm, with depolarization at 1064 nm) and maximum receiver efficiency. An off-axis parabola is used for the telescope, allowing 100% of the laser energy to reach the atmosphere. The CPL is designed with a nominal 100 microradian field of view to minimize effects of multiple scattering. CPL data products are typically provided at 30 m vertical resolution and 1 second horizontal resolution (~200 m at the nominal ER-2 speed of 200 m/s).


Table 3-2. ATTREX Payload Instrument Summary

Acronym Name Measurement Weight (lb)

Power (W)

Sampling Rate

Error Uncertainty

P/L Zone

CPL Cloud Physics Lidar Aerosol/Cloud Backscatter 366

O3 NOAA Ozone

Photometer

O3

40 2 Hz

AWAS Advanced Whole Air

Sampler

Numerous Tracers with

Varying lifetimes

UCATS UAS Chromatograph

for Atmospheric Trace

Species

O3

, CH4

, N2

O, SF6

60 250

(450 during

warm

up)

PCRS Picarro Cavity

Ringdown

Spectrometer

CO2

, CO, CH4

, or H2

O 110

ULH UAS Laser

Hygrometer

H2

O vapor (ppmv) 24 1-40 Hz > 0.05

ppmv or

1%

10%

DLH Diode Laser

Hygrometer

H2

O 50

Hawkeye Ice Crystal size

Distributions

135

SSFR Solar Spectral Flux

Radiometer

Radiative Fluxes 40

MMS Meteorological

Measurement System

Temperature, winds,

turbulence

65

MTP Microwave

Temperature Profiler

Temperature Profile 24 1 prof/15 s <1 K <0.05 K

Mini-DOAS Differential Optical

Absorption

Spectrometer

BrO, PAN 28

Figure 3-X. Ozone (O3) Ozone Optics


The CPL fundamentally measures the total (aerosol plus Rayleigh) attenuated backscatter as a function of altitude at each wavelength. Considerable data processing is required to separate backscatter from extinction and aerosol backscatter from Rayleigh. However, for trasmissive cloud/aerosol layers, using optical depth measurements determined from attenuation of Rayleigh and aerosol scattering, and using the integrated backscatter, the extinction-to-backscatter parameter (S-ratio) can be directly derived. This permits unambiguous analysis of cloud optical depth since only the lidar data is required; there is no need to use other instrumentation nor is there need for assumption of aerosol climatology. Using the derived extinction-to-backscatter ratio, the internal cloud extinction profile can then be obtained. This approach to directly solving the lidar equation without assumption is a standard analysis approach for backscatter lidar and more complete detail can be found at: http://cpl.gsfc.nasa.gov.

3.2.2.2. Ozone (O3)

(Gao, NOAA)

The NOAA UAS Ozone photometer is an autonomous dual beam UV absorption photometer for in situ ozone (O3) measurements. It has been designed to achieve high sensitivity and fast response in a small package with minimal power requirements. Additionally, a



compact flow management system has been integrated that regulates the sample flow. The O3 concentration is calculated from a differential absorbance measurement between sample and reference cells. It has flown on the NASA WB-57F during the TC4 and NOVICE missions.

An optical-isolator type configuration is utilized to fold the UV beam inside the absorption cells (see Fig. 1), giving an effective 60 cm path length with a 30 cm absorption cell for a compact instrument. In this setup, the unpolarized output of a mercury lamp is collimated and passes through a 254 nm band pass filter before being vertically polarized by a polarizing beam splitter (PBS). The resulting polarized beam is then split into two beams using a non-polarizing beamsplitter, with half of the light entering each of two absorption cells unimpeded though another polarizing beamsplitter. On the distal end of the absorbance cell, the polarization is rotated by 90 degrees using a precision quarter wave plate. After the second pass through the absorption cell, only this horizontally polarized light is then split out to a silicon photodiode.

Besides doubling the optical path length, this design minimizes wall effects and rejects any light that may be scattered in the cell by various mechanisms. The shorter cell has the added advantage of shorter sample air residence time inside the cells, thus leading to a better time resolution. Furthermore, the dual pass geometry allows an optimally compact design by putting significant optical and electronic components on one end of the cell only.

3.2.2.3. Advanced Whole Air Sampler (AWAS)

(Atlas, U. Miami)

The Whole Air Sampler (WAS) collects samples from airborne platforms for detailed analysis of a wide range of trace gases. Detailed analysis in the laboratory is by a variety of gas chromatographic techniques that use mass spectrometric, flame ionization, and electron capture detection. The compounds that are typically measured from the WAS include trace gases with sources from industrial midlatitude emissions, from biomass burning, and from the marine boundary layer, with certain compounds (e.g. organic nitrates) that have a unique source in the equatorial surface ocean. The use of a broad suite of tracers with different sources and lifetimes provides powerful diagnostic information on air mass history and chemical processing that currently is only available from measurements from whole air samples. Previous deployments of the whole air sampler have shown that the sampling and analytical procedures employed by our group are capable of accessing the wide range of mixing ratios at sufficient precision to be used for tracer studies. Thus, routine measurement of species, such as methyl iodide, at <= 0.1 x 10-12 mole fraction, or NMHC at levels of a few x 10-12 mole fraction are possible.

In addition to the tracer aspects of the whole air sampler measurements, WAS measureS a full suite of halocarbon species that provide information on the role of short-lived halocarbons in the tropical UT/LS region, on halogen budgets in the UT/LS region, and on continuing increasing temporal trends of HFCs (such as 134a), HCFCs (such as HCFC 141b), PFCs (such as C2F6), as well as declining levels of some of the major CFCs and halogenated solvents. The measurement of those species that are changing rapidly in the troposphere also give direct indications of the age and origin of air entering the stratosphere across the tropical tropopause. Thus, several estimates of air transport rates and age will be available from the measurement of species proposed here, plus the measurement of CO2 and SF6 by others on the Global Hawk platform.

The UM sampler (formerly NCAR) has flown in an automated version a number of airborne platforms including the NASA ER-2 and WB-57. Different versions, all operating on the same basic principle, have been deployed over the past 15 – 20 years. On each of these platforms the instrument was reconfigured to fit in the available space. Thus, the WAS had missions on the ER-2 nosepod, wingpod, superpod, and belly tank. On the WB-57, a 40-canister and 50-canister configuration has been flown. For tropospheric aircraft, the WAS also has been configured into different geometries to fit into available space. A totally redesigned WAS has recently been used on the NSF Gulfstream. The basic components include an inlet, compressor, canisters, pressure sensors, and computer control. The WAS-GH will take the same features of the existing and proven technology used on the existing WAS to reconfigure the sampler into the necessary geometry for the Global Hawk. Modifications for the WAS-GH will be lighter sample canisters to allow a greater number of samples to be collected per mission.

3.2.2.4. UAS Chromatograph for Atmospheric Trace Species (UCATS)

(Elkins, NOAA)


Figure 3-X. UAS Chromatograph for Atmospheric Trace

Species (UCATS)

Table 3-3. Trace Gases that UCATS can measure in the atmosphere.

Trace Gas Units Sampling Rate Error Accuracy

N2O ppb* 70 seconds ±0.2-0.5% ± 1%

SF6 ppt* 70 seconds ±0.8-1% ± 1%

H2 ppb 140 seconds ±2-3% ± 1%

CO ppb 140 seconds ±2-5% ± 1%

CH4 ppb 140 seconds ±0.4-0.8% ± 1%

CFC-11 ppt 70 seconds ±0.3-0.6% ± 1%

CFC-12 ppt 70 seconds ±0.3-0.6% ± 1%

Halon-1211* ppt 70 seconds ±0.5-0.8% ± 1%

O3** ppb 10 Econds > of ±1 ppb

or ±2%> of ±2 ppb or ±3%

H2O** ppm* 1 second ±2-3% ±3-5%

*ppm … parts per million; ppb … parts per billion; ppt … parts per trillion

**Requires replacing H2

-CO-CH4 channel

Figure 3-X. Picarro Cavity Ringdown Spectrometer (PCRS)


The Unmanned aircraft systems Chromatograph for Atmospheric Trace Species UCATS was designed and built for autonomous operation aboard the NASA Altair Unmanned Aircraft System (UAS) in an unpressurized, ambient temperature environment. To date it has amassed >140 operational flight hours in Altair in 2005 and 2006, including three flights >20 hours in duration. UCATS has recently operated on NCAR’s HIAPER (G-V) on the START-08 and HIPPO/1 research experiments and has over 200 hours amassed on manned aircraft. It is currently being integrated into payload position #15 on the NASA Global Hawk UAS platform for the Global Pacific (GloPac) experiment in January-February 2010.

UCATS is three different instruments in one enclosure (Figure 3-X): (1) a two-channel gas chromatograph (GC) that measures nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrogen (H2), carbon monoxide (CO), and methane (CH4), (2) a dual-beam ozone photometer (OZ or O3), and (3) a tunable diode laser (TDL) spectrometer for water vapor (WV or H2O). The H2-CO-CH4 GC channel may be switched between flights for measurement of

atmospheric chlorofluorocarbon-11 (CFC-11), CFC-12, and halon-1211 (details in Table 1). The UCATS enclosure measures 41 x 46 x 25 cm (W x L x H, 16.1 x 18.1 x 9.8 inches) and weighs 28 kg (62 lbs). Power consumption is 9 Amps @ 28 VDC (250 W), and is 16 A (450 W) during warm-up. External to the UCATS enclosure are a Teflon-diaphragm pump (KNF, Inc) for sampling air through an external inlet, two high-pressure aluminum aircraft cylinders for nitrogen and calibrated whole air, and an inlet. On the ground, UCATS can have a ground station consisting of a keyboard, monitor, and mouse for verifying operation before flight and is removed prior to flight

for UAS unattended operation. UCATS can send real time data down from the plane during flight if Iridium or ku-band satellite communications along with on board RJ-45 local network connections is available. The data are displayed using the Google Earth application showing preliminary mixing ratios of large signal GC gases, ozone, and water vapor.

3.2.2.5. Picarro Cavity Ringdown Spectrometer (PCRS)

(Wofsy, Harvard)

The sensor will be a Picarro G1303-mc cavity ringdown spectrometer modified for use on our airborne platform. The instrument will measure concentrations of CO2, CH4, H2O, and CO with 5s/5 min RMS variations of [<200 ppbv / <50 ppbv], [<2 ppbv / 0.7 ppbv], [100 ppmv / 50 ppmv], and [<20 ppbv / <5 ppbv], respectively. All of these measurement specifications were met or exceeded in actual field measurements, 75 hours of flights of a prototype instrument, except for the CO channel (see below). Picarro has successfully marketed a separate CO sensor for use on the ground, of very similar design to the planned sensor.



The instrument will be modified for use on our platform by the Harvard team, as follows: (1) Power supplies will be replaced to conform to platform specifications; (2) A complete calibration system will be added to ensure that measurements are traceable with high accuracy to world standards; (3) The sensor will be repackaged and integrated onto the platform; (4) an inlet will be installed. The core sensor weighs about 45 lbs and with the calibration and integration components the complete system will weigh about 75 lbs.

A flight prototype of this system, measuring CO2, CH4, and H2O, was flown on our BARCA aircraft mission in Amazonia in May, 2009, along with our airborne CO2 sensor (> 1000 hrs on the ER-2, WB-57F, and low-altitude platforms). The flights were conducted over a period of 2 weeks in Manaus, Brazil, under very difficult conditions (no air conditioning, no lab facilities, unpressurized aircraft). The two independent CO2 sensors agreed to an astounding 0.02 ppm on average, with an RMS error < 0.1 ppm. Our airborne sensor was calibrated every 20 minutes in flight. The Picarro sensor was calibrated in Jena before being shipped to Brazil, and it was never calibrated in flight. This sensor thus exhibited unprecedented stability and performance. The performance for CH4 was also extremely good, with very low noise and repeatability, but we did not have another continuous sensor for checking calibration stability. Comparisons with flask samples await return of the canisters to Germany.

We view the three channels tested in flight as TRL 8 and the CO channel as TRL 7.

3.2.2.6. UAS Laser Hygrometer (ULH)

(Herman, JPL)

The UAS Laser Hygrometer (ULH) is an autonomous spectrometer to measure atmospheric water vapor from airborne platforms. It is designed for long-duration flights of the NASA Global Hawk UAS to monitor upper tropospheric (UT) and lower stratospheric (LS) water vapor. It is a single-channel, near-infrared, open-path tunable diode laser spectrometer that measures atmospheric water vapor in-situ. ULH operates in two modes: harmonic wavelength modulation spectroscopy and direct absorption. The harmonic spectroscopy is precise and fast: averaged data are recorded at a user-adjustable rate between 1 and 40 Hz. The direct absorption measurements are highly accurate, and are used as an in-flight calibration of the faster harmonic data. The water vapor volume mixing ratio is calculated from the Beer-Lambert Law. ULH is the latest in a series of laser hygrometers that have been developed in our group at the Jet Propulsion Laboratory, California Institute of Technology. It made successful measurements on all three NOVICE flights in 2008, and is scheduled to participate in the upcoming Global Hawk Pacific Mission (GloPac) in early 2010. Our previous laser hygrometers have participated in numerous NASA aircraft missions from 1997 to the present, including POLARIS, CAMEX, ACCENT, SOLVE, CRYSTAL-FACE, Aura Validation Experiment (AVE), AVE-WIIF, MidCiX, PUMA-A, Costa Rica AVE, and TC4. ULH has several features that enhance the science and take advantage of the command, control, and communications available on the Global Hawk platform. First and foremost, we use a stronger water absorption line than previously used in our laser hygrometers. The stronger water absorption improves sensitivity to measurements in the dry TTL. Laser scans are controlled by software, and can be changed by commands uplinked from the ground. Likewise, the data rate and number of scans to average can also be modified. This adds flexibility in how we optimize data collection, precision, and accuracy in different parts of a Global Hawk flight. Provided that meteorological data are available (static temperature and static pressure), real-time water vapor volume mixing ratios can be downlinked from the instrument to the ground.

3.2.2.7. Diode Laser Hygrometer (DLH)

(Diskin, LaRC)

The NASA Langley/Ames Diode Laser Hygrometer (DLH). The DLH instrument has a rich heritage, providing high quality (high time resolution, high accuracy/precision) measurements for many major atmospheric field campaigns on several aircraft. The DLH is a near-infrared external open-path diode laser spectrometer operating in the ~1.39 µm water vapor absorption band. This series of instruments has accumulated more than 1000 flight hours providing state-of-the-art H2O(v) measurement capabilities on the CIRPAS Twin Otter and NASA DC-8 and WB-57 aircraft for the past 15 years.

The DLH is an open path airborne tunable diode laser-based instrument which operates in the near-infrared spectral region at a wavelength of approximately 1.39 µm. The DLH measures the H2O(v) mixing ratio in the atmosphere by wavelength modulated differential absorption The line-center 2F signal is normalized by the collected DC signal, providing a resultant that is insensitive to optical power and thus insensitive to alignment and to atmospheric obscuration along the optical path. The absorption path utilized by the DLH is external to the aircraft, and it is formed between a laser transceiver and a retroreflecting panel. The combination of external path and normalized 2F detection yields a measurement which can be made accurately even in the presence of clouds and precipitation, and which is insensitive to interferences caused by the aircraft itself (e.g. vaporization of condensed phase H2O, cabin leaks, etc.). For more information on the DLH, see [Diskin 2002; Podolske 2003; Vay 1998]. Since these references were published, we have made significant changes in the operation of the DLH by replacing the operator-intensive drive and control electronics with a new microprocessor-driven system. This fully autonomous system controls the laser operation, including its temperature and current; conducts many short-duration calibration events during each flight; collects, processes and stores data in real-time; and provides an output signal to be used by the


Figure 3-X. Solar, Infrared Radiomoters (SSFR)

Figure 3-X. Hawkeye


aircraft’s data system. In addition, the use of our all-digital lock-in / data acquisition system allows us to capture more information on the absorption line-shape during each modulation cycle. The DLH measurements have been extensively intercompared with other water vapor sensors, both on the DC-8 and other aircraft during dedicated intercomparison activities, for example, during INTEX-B and ARCTAS.

3.2.2.8. Hawkeye (Lawson, Spec Inc.)

Hawkeye is the culmination of two decades of innovative instrument development at SPEC Incorporated. The probe measures the size distribution of cloud and precipitation particles, provides high-resolution (2.3 micron pixel) images of cloud particles and removes artifacts from ice particle shattering. This is accomplished by eclectic combination of technology developed in three existing SPEC optical cloud particle probes: 1) A fast FSSP, that measures size distributions from 1 to 50 microns and records individual particle statistics and removes shattered particles using inter-arrival times, 2) a cloud particle imager (CPI) with upgraded imagery capable of recording up to 500 frames per second, and 3) a 2D-S (Stereo) probe that is configured with one channel to provide full-view images of particles from 10 microns to 1.28 mm, and a second channel configured to provide full-view images of particles from 50 microns to 6.4 mm. Thus, using particle

dimensions along the direction of flight will produce particle size distributions from 1 micron to several cm.

Hawkeye uses particle inter-arrival times to remove the effects of ice particles that shatter on the probe inlet. The probe and data acquisition system are specifically designed for installation and autonomous (unattended) operation on NASA research aircraft, including the Global Hawk unmanned aerial system (UAS). The instrument provides vastly improved measurements of particle and precipitation size distributions, particle shape, extinction coefficient, effective particle radius, ice water content and equivalent radar reflectivity.

3.2.2.9. Solar, Infrared Radiometers (SSFR)

(Pilewskie, Univ Colorado)

Two instruments are planned for measuring solar and terrestrial radiation: The Solar Spectral Flux Radiometer (SSFR, Pilewskie et al., 2003) covers the near-ultraviolet, solar, and near-infrared wavelength range from 360 nm to 2200 nm. The Kipp & Zonen CG4 pyrgeometer

provides broadband infrared irradiance from 4.5 – 42 μm. Optical inlets for both instruments are mounted on top and at the bottom of a platform and provide upwelling,

downwelling, and net irradiance. The SSFR took part in numerous experiments, including NASA CRYSTAL-FACE, MILAGRO, TC4, ARCTAS as well as the NOAA Gomaccs, ARCPAC, and ICEALOT missions. The CG4 was deployed during NOAA ARCPAC. The two instruments together provide complete measurements required for the cloud energy budget, radiative forcing, and heating rate. The spectral resolution of SSFR is crucial to distinguish radiative effects of clouds from those of, e.g., the underlying surface. It also allows an independent retrieval of cloud optical thickness and effective drop or crystal radius.

The SSFR consists of two rack-mounted spectroradiometers that are connected to the optical inlets via a fiber optic. The wavelength range is covered by using two spectrometers per optical inlet: a grating spectrometer with a Silicon CCD array (360-1000 nm, 8 nm spectral resolution) and a spectrometer with Indium-Gallium-Arsenide linear array detector (900-2200 nm, 12 nm resolution). The spectrometers are calibrated in the laboratory with a NIST-traceable blackbody (tungsten-halogen 1000W bulb). The radiometric stability of the SSFR is carefully tracked during the course of a field experiment with a portable field calibration unit with a highly stable power source and 200W lamps. The data were corrected for the angular response of the light collectors and for changes in downward irradiance due to aircraft attitude. The CG4 provides high accuracy measurements of infrared radiation even under direct insolation conditions, without the need for shielding or correcting for shortwave heating effects. It is calibrated in a heat-bath with adjustable temperatures that cover temperature and radiation regimes that occur under experiment conditions. In addition, they are cross-calibrated with


Figure 3-X. Meteorological Measurement System (MMS)


radiometers that are traced back to the world standard from the World Radiation Centre in Davos, Switzerland.

3.2.2.10. Meteorological Measurement System

(MMS)

(Bui, ARC)

The MMS, developed at NASA Ames Research Center, is a PI-led airborne instrument that provides calibrated, science quality, in situ state measurements of static pressure, static temperature, and three-dimensional wind and turbulence indices. Differencing the measured aircraft ground velocity from the true air speed vector produces the 3-dimensional wind vector. The embedded GPS inertial navigation system provides the aircraft attitude, position, velocity, and acceleration data. The air stream velocity is obtained from the radome pressure ports, pitot-static pressure system, and temperature probes.

System calibration of the MMS consists of: (1) individual sensor calibrations; (2) sensor dynamic response tests; (3) laboratory determination of the dynamic behavior of the inertial navigation system; (4) in-flight aerodynamic calibration; and, (5) comparison with radiosonde and radar-tracked balloons. Individual sensors are routinely re-certified to NIST standard by their respective calibration laboratories.

In the final archival data set, the MMS will provide 20-Hz measurements of time, pressure, temperature, wind vector (u, v, w), position, attitude (pitch, roll, heading), angle of attack, yaw angle, true airspeed, aircraft velocity (eastward, northward, vertical), vertical acceleration, and turbulence.

After a thorough and proper system calibration, the following accuracy is achievable:

Typical value at DC-8 Altitude Typical value at ER-2 Altitude

Pressure (p) 200 mb ± 0.3 mb 60 mb ± 0.3 mb

Temperature (T) 215 K ± 0.3 K 180 K ± 0.3 K

Horizontal wind (u, v) 30 ms-1 ± 1 ms-1 30 ms-1 ± 1 ms-1

Vertical wind* (w) < 1 ms-1 0.1 ms-1 resolution < 1 ms-1 0.1 ms-1 resolution

The MMS team is uniquely qualified to make these measurements. It has extensive field experience having participated in STEP-1986, AAOE-1987, AASE-1989, AASEII-1991, SPADE-1992, ASHOE/MAESA-1994, STRAT-95, SUCCESS-1996, SONEX-1997, POLARIS-1997, CAMEX-3/4-1998/2001, SOLVE-2000, CRYSTAL-FACE-2002, MidCix-2004, JuneAVE-2005, CRAVE-2006, NAMMA-2006, TC4-2007, and NOVICE-2008. Enhancements to the MMS are underway for observations on the NASA Global Hawk Unmanned Airborne System (UAS) with a target field measurement campaign: Global Hawk Pacific Mission (GLOPAC) in 2010.

3.2.2.11. Microwave Temperature Profiler (MTP)

(Mahoney, JPL)


Figure 3-X. Microwave Temperature Profiler (MTP)

Table 3-4. Target Species of the Mini-DOAS instrument*

Species Sensitivity/precision as a function of altitude

Estimatedaccuracy

(%)*

10 km 15 km 20 km BrO 0.7 ppt 0.9 ppt 1.2 ppt 8O3 35 ppb 80 ppb 140 ppb 2NO2 13 ppt 20 ppt 33 ppt 5OClO 3 ppt 4.5 ppt 9 ppt 12IO 0.2 ppt 0.4 ppt 0.5 ppt 25OIO 0.2 ppt 0.4 ppt 0.5 ppt 55* sensitivity and precisions are equal; accuracy estimates are derived from

published absorption cross sections

Figure 3-X. University Heidelberg

Mini-DOAS instrument


The Jet Propulsion Laboratory Microwave Temperature Profiler (MTP) is a passive, microwave radiometer that measure the brightness temperature of the atmosphere due to the natural thermal emission from oxygen molecules near 60 GHz. During a 15-second scan cycle from near-zenith to near-nadir in the flight direction, measurements are made at three frequencies and at ten elevation angles. The thirty measured brightness temperatures are converted to air temperature versus altitude by using a modified statistical retrieval procedure developed especially for the airborne application. This quasi-Bayesian procedure selects between many sets of retrieval coefficients to determine which set has corresponding brightness temperatures that best match the measured brightness temperatures. This set of retrieval coefficients is then used to retrieve a temperature profile above and below flight level. In addition, by converting temperature profiles along an aircraft's flight track to potential temperature profiles, and then identifying levels of constant potential temperature (or isentropes), MTP data can be used to study of atmospheric dynamics. This will be especially important during ATTREX because recent modeling results suggest that mesoscale variability is the primary mechanism needed to reproduce observed quantities in cirrus clouds.

This is exactly what the MTP isentropes measure!

MTPs are small, lightweight, easily integrated and can fly autonomously. They currently fly on five research aircraft, and will fly on the first Global Hawk mission (GloPac) in January 2010. In more than two decades of very successful airborne research, MTPs have accumulated 4443 flight hours (on 793 flights) during 50 field campaigns. More information can be found at the MTP web site: http://mtp.jpl.nasa.gov.

3.2.2.12. Mini-DOAS - Differential Optical

Absorption Spectrometer

(Pfeilsticker, IUP Heidelberg)

The Mini-DOAS instrument (weight 14 kg, power 25 W) is an automated UV/vis spectrometer (310-500nm), which uses scattered solar light in the limb (horizon) and nadir

(downward) geometry to detect path-integrated concentrations of BrO, O3, NO2, OClO, IO, OIO, and O4. Spectral retrieval of trace gas slant column densities from the measured absorption spectra are achieved using established DOAS methods available both at the Univ. Heidelberg and UCLA. Past deployments of the Mini-DOAS instrument (or variants of it) include 16 flights on high altitude research balloons (LPMA/DOAS, LPMA/IASI and

MIPAS-B), the DLR Falcon aircraft and in the near future on the DLR HALO aircraft and on the Russian Geophysica. Table 3-4 lists the characteristics of the mixing ratios determined by the Mini-DOAS.

3.3. Development Approach

3.3.1. Management and Planning

The ATTREX project will managed in accordance with NPR 7120.8: NASA Research and Technology Program and Project Management Requirements.

The overall scientific and technical direction of the project will be established by the PI, and implemented and tracked by the Project Manager. The PM will develop the overall project plan, and other supporting plans (system engineering, operations, etc.), and will also facilitate project status reporting between the PI, the ESSP

program, as well as other project elements.

Planning at the project level includes base lining, verifying and tracking science requirements (compliance matrix), and conducting other system engineering activities in support of the overall project management. The Project Manager will also oversee project



level risk, configuration, contract, and safety and mission assurance activities. The primary risk management and project system engineering functions are the responsibility of the Project Manager.

In addition, the Project Manager is responsible for project level reviews, such as the MRR and project status review.

For the instruments on the payload, most are fully developed at this point. However, each PI will provide a schedule and task plan which outlines the steps prior to vehicle integration. This will be used by the Project Manager to assess project readiness and by the Mission and Payload Managers to develop required interface documentation and control. The primary configuration management and payload system engineering functions are the responsibility of the Payload Manager.

The Mission Manager will coordinate appropriate safety review boards, technical briefs, and Flight Readiness Reviews (FRRs) in accordance with the requirements of NPR 7900.3B: Aircraft Operations Management Manual.

Science planning, including flight planning, will be lead by the PI and Deputy PI. Operations planning will be lead by the Mission Manager. Planning for assembly, integration, and test activities is described in § 3.4.

3.3.2. Developmental Status

All of the instruments proposed for the ATTREX mission have Technology Readiness Levels (TRL) ranging from TRL 6 to TRL 9, i.e., from system demonstration through fully operational capablities. Table 3-3 shows the heritage and development status for these instruments.

3.3.3. Deployment Sites

As described in § 2.1, there are three primary deployment sites, and one integration and test site, in the ATTREX mission: Hawaii, Guam, and Darwin, Australia, and DFRC. Initial assessment of these sites indicates Guam and Darwin are suitable operational sites, and, in fact, the Air Force has previoulsly deployed Global Hawks from Guam. Final decision on which deployment sites will be used will be determined after a site survey is conducted by ESPO and the Golbal Hawk Project Office in late FY10, and prior to the PDR.

Factors in the selection of appropriate sites include:

Runway length and condition. Airspace access (including Certificates of Authorization). Communications (including coverage). Government/Foreign approvals. Hangars and other required facilities. Transport & logistics.

A summary of the primary deployment sites, and potential alternate sites, is shown in Table 3-4.

3.4. Assembly, Integration, Test

3.4.1. Planning

Planning for all ATTREX assembly, integration, and test activities will be lead by the Global Hawk Project Office, in conjunction with the Earth Science Project Office, and in accordance with the ATTREX Project Plan. Details are provided in the paragraphs below.

At the begining of the integration process, each PI will provide Payload Information Form (PIF) which delineates the requirments of each instrument to the vehicle, identifies potential hazards, and any unique installation of operational constraints. This forms the basis of the engineering work to be done for instrument installation. Once the enginnering of the istallation design is complete, and configuration-controlled Payload Data Package (PDP) is developed and maintained. Changes to the PDP are approved by the DFRC Configuration Review Board.

3.4.2. Integration

For integration and each deployment, the mission and payload managers will develop detailed integration schedule, based on nominal planning procesdures of the Airborne Science Directorate at DFRC, and lessons learned from the GLOPAC mission (§ 3.4.4). Integration activities will be conducted in Hangar 4801 and the Global Hawk Research Aircraft Integration Facility (RAIF) in Building 4840. These facilities provides office space, tools, and other accommodations to support integration of PI instruments onto the Global Hawk.


Table 3-5. Notional Integration Timeline

Event Weeks prior to Deployment

Payload Information Form (PIF) 24

Integration Design & Engr Complete

Payload Data Package

10

Configuration Review Board (CRB) 9

Security Access Requests 8

PI “Hand On” 4

All PI HW at Integration 3

PI “Hand Off” 2

Integrated System Check 1.5

TRR/FRR 1

Test Flight(s) 1

TRANSIT -


3.4.3. Testing

Once the integration phase is completed, the Global Hawk Project Office will conduct a series of tests prior to vehicle flight. These tests include a Bench Test, which confims operation of the instrument, an Integrated System Test, which assures all instruments are performing nominally and in concert with the entire payload, and a Functionl Test, which ensures the entire vehicle and instrument system is ready to fly. DFRC will conduct appropriate safety review boards, technical briefs, and Flight Readiness Reviews in accordance with the requirements of NPR 7900.3B: Aircraft Operations Management Manual.

Prior to all Global Hawk flights, the PIs will also participate in a vehicle communications test. The number, duration, and objectives of test flights prior to deployment will be determined by the Platform Scientist and Mission Manager, though at least one test flight will be conducted prior to any deployment operations.

3.4.4. Timeline

The overall mission schedule is shown in § 4.3, including estimated integration times for the test phase and deployment operations. However, a notional integration timeline is shown in Table 3-5.


Figure 4-1. ATTREX Organization Chart


4.0. Management

4.1. Management Approach

ATTREX assembles a world-class set of scientists and instrument teams with NASA’s latest long endurance Unmanned Airborne System (UAS) that will bring about a successful Earth Venture-1 (EV-1) investigation. This team is led by the Principal Investigator (PI), Dr. Eric Jensen, who is responsible to NASA Earth System Science Pathfinder (ESSP) Program Office for achieving the ATTREX science objectives within the EV-1 cost and schedule constraints. Dr. Jensen delegates the day-to-day implementation responsibility to the Project Manager (PM), Mr. Mike Gaunce and the Earth Science Project Office (ESPO) at NASA ARC. The PI & PM work together on a daily basis to maintain a clear understanding of the project overall status including all risks to science, cost, schedule, and performance. The ATTREX manage-ment processes are designed to provide clear lines of authority and accountability, frequent and accurate communication, rapid problem identification and resolution, good visibility of team performance with respect to cost and schedule, integrated risk management, and comprehensive technical and programmatic reviews.

The ATTREX investigation will be managed according to well-established practices of project management and systems engineering and compliant with NPR 7120.8. Further, ATTREX will operate in a mode that emphasizes the importance of containing costs well within the limits of the EV-1 AO and established by ESSP. It is the ATTREX objective to integrate the ESSP, the PI, ESPO, instrument teams, theory

and modeling members, and the Global Hawk Project Office into a single team that together will meet the challenges of the project. The ATTREX investigation organization is shown in Figure 4-1. In this organization, the PI is fully responsible for the whole investigation by balancing scienctific, technical, schedule, and cost objectives and thereby has final authority for all key decisions. The PI reports to ESSP through the their Mission Manager. The PI leads

the science team and works directly with the PM,

delegating significant authority, so that the PM can

accomplish much of the mission.

4.1.1. Team Member Coordination and

Communication

Despite being a distributed team, we have setup the project to maximize project communication and foster a great team environment. The PM is responsible for the management coordination of ATTREX, and will

lead ESPO, comprising of a Deputy PM, Business Manager, Systems Engineering (SE) Lead, and Safety & Mission Assurance (SMA) Lead. ESPO will track programmatic risks, costs and schedules associated with the instruments, Global Hawk, and deployments. Members will report schedule progress, including a slack assessment on critical paths, at monthly Management meetings. In addition, at each Management meeting, they will review status and update a detailed list focusing on the current and coming month’s work.

The SE Lead is responsible for assuring the technical approach is consistent with requirements and appropriately implemented and vali-dated. The SE Lead will focus on technical status for purposes of design coordination, problem resolution, and interim progress reports on key technical issues working with the instrument teams and the GH Project Office.

4.1.2. Reviews and Progress Reporting to ESSP

The ATTREX will have key system-level reviews, tailored to the Earth Venture-1 management approach but consistent with the requirements of NPR 7123.1, NASA Systems Engineering Processes and Requirements. The reviews are shown in the schedule Figure 4.3-1. The two formal gate reviews are the Confirmation Review (CR) for KDP-C and the Mission Readiness Review (MRR) for KDP-E. The System Requirements Review (SRR), Preliminary Design Review (PDR), Critical Design Review (CDR) are project reviews but not formal gate reviews.

In order for the ESSP Program Office to execute its responsibility for funding and oversight of the project, the ATTREX team will provide complete, accurate and timely programmatic forecasts and reports. ATTREX will use a reporting and review process that provides ESSP a



constant level of technical and programmatic oversight. The PI supported by the PM and ESPO will report directly to the ESSP Mission Manager.

The PM will implement a thorough and complete system of progress reviews and reporting that will provide adequate ATTREX project status insight to the Program Office, the ARC Center Management Council (ACMC), and the NASA HQ/SMD/ESD. The PM will convene a joint Management and Technical Status Meeting on a monthly basis via telecon for a comprehensive review of the overall project status. In this forum schedule slack analysis, cost performance and reserves, technical performance, and risk posture will be reported by each team member. The results of these reviews will be used in preparation for the Program Office and ACMC monthly status reviews.

Each ATTREX team member will report their technical, cost and schedule status at the monthly Management and Technical Status Meetings, with electronic copies submitted to the project. These data will be summarized along with 533 financial reports and reports of project-maintained metrics, and incorporated into the monthly report from the ESPO to the Program Office. The ESSP Mission Manager will be invited to attend all project weekly and monthly management meetings.

The ATTREX Project and ESSP will have quarterly review meetings for the full duration of the project. For costing purposes, once a year, key project team members will travel to LaRC. It will also be assumed that the ESSP office will travel once a year to ARC for a quarterly meeting of similar duration. The other two quarterly meetings each year will be 1-day meetings done via telecon and Webex so that no travel is required.

4.2. Risk Management

The establishment and implementation of the ATTREX Risk Management Plan will provide the project team a means to identify, manage, mitigate, track, and control risks to achieve mission success under a fixed budget and schedule. The risk management process is ultimately the responsibility of the PM, but risk management activities will be practiced at every level within the ATTREX project team teams to evaluate and proactively plan, address, and update associated risks.

Any member of the project can recommend an item be tracked as a risk, but the PM formally manages the process, and therefore approves additions. The risk management approach will be tailored from NPR 7120.8 guidelines, which support the concepts of continuous risk management (CRM).

CRM will be incorporated into the existing Technical and Management meetings to ensure the visibility of risk information to all parties. The Systems Engineering Lead will be assigned to oversee the CRM process. An integral part of the success of risk management is communication. An atmosphere of free exchange will be promoted on the ATTREX project to ensure all concerns regarding even perceived risks are voiced. Table 4-1 has the current set of ATTREX risks.


Table 4-1. Risk Mitigation

Risk Area Proba-bility Conse-quence Mitigation Plan Status

Cost overruns and schedule delays in adapting TRL6 instruments to

the Global Hawk platform3 2

-Reserves are estimated higher to compensate for this uncertainty

-There is 2 additional months of schedule slack between I&T and first science campaignG

The availability of a wing pod for the Hawkeye instrument is delayed

from current schedule of 4/20112 4

-Continue to look at a configuration that does not require a wing pod

-Investigate the technical solution for developing a wing blister that is adequate to fly Hawkeye

-Halfway during the campaign swap out CPL for Hawkeye

-Monitor wing pod development

G

Obtaining Certificates of Authorization (COA) over some regions we

plan to fly with some of the deployment sites2 3

-Site visits during Phase A will identify untenable deployment sites G

Cost of Deploying Global Hawk outside of DFRC is more than

budgeted

3 3

-Early planning of deployment will identify issues and determine if ATTREX will be the first

project to deploy a GH

-Reserves are estimated higher due to this uncertainty

-First deployment is in Guam, actual costs can be analyzed and used to move other

deployments to DRFC if considered too costly

G

A Global Hawk may not be available at the campaign times laid out in

the proposal2 3

-Upon selection, ESPO will submit flight request and negotiate acceptable schedule with

ESSP & GH PO.

-ATTREX has flexibility to move the seasonal order of the campaigns

-Currently have 10 months of schedule reserve in completing campaigns

G

Availability of the GH Portable Operations Room is delayed from

current schedule of X/2011

-X months schedule margin in current plan

-Operate first deployment from DRFCG

Hazardous weather conditions put GH at risk of damage

1 4

-Campaign location, seasonal weather patterns, and flight plans will be designed to minimize

expected convective air.

-Flight rules on safe weather thoroughly understood by the Team

-Deployed Meteorology team will monitor weather before and during 30 hour flight.

G


4.3. Schedule

The top-level view of the ATTREX master schedule is shown in Figure 4-2. The schedule shows the modifications and deployment planning for the Investigation including the Phases A through F and their associated gate milestones or Key Decision Points (KDP). Other


Figure 4-2. Mission Schedule


review milestones are shown, and the deployments. A full year after the last deployment is set aside for data analysis , modeling, and publication of results.

ESPO at ARC will maintain the integrated master schedule showing the critical path, schedule reserves, and detailed project milestones, including peer and system level reviews. The integrated master schedule will be developed during Phase A. During Phase B, the master schedule will be updated and then baselined at the Confirmation Review. Once baselined, all progress will be measured against the fixed baselined integrated master schedule.

The PM and DPM will manage the schedule by tracking key milestones weekly, and will use the WBS with a modified Earned Value (EV) process to track progress against dollars. The PM will track, manage and update a detailed list focusing on the coming month’s work. This list will be reviewed in each bi-weekly Management IPT meeting. The project master schedule will be updated monthly. The monthly status dates are at the end-of-month, and will be tracked using “Plan vs. Actual” format to measure progress against baseline late dates. The instrument teams will submit schedule updates to the PM by the first week of the month. Schedule issues (inconsistencies in statusing, issues, links, etc.) will be worked upon receipt and reviewed with the PM until resolved or mitigated. Monthly, the critical path assessment will be performed to determine real or potential drivers, along with a slack assessment to determine if work is getting done as planned. Trending analysis is performed by comparing progress/slips from baseline plan and/or previous update(s). Performance data will be rolled into metrics and highlighted items, and reported monthly.


Table 4-2. Descope Options

Descope Impact Est. Cost Savings ($K-

RYD)

Preferred Decision Milestone

Fall deployment is stationed from DFRC rather than

Hawaii

-Less data collection time is spent in the TTL

- Eliminates higher deployment travel cost for Project staff

- Eliminates overseas deployment cost and complexity for Global Hawk

400 After first deployment -Winter

2012

Summer deployment is stationed from DFRC rather

than Hawaii

-Less data collection time is spent in the TTL



400 KDP-E

Eliminate an instrument -Robustness of measurement will be reduced such fewer samples or lower resolution 800-1000 PDR

Eliminate fall deployment completely -No seasonal transition data collected to support model fidelity



1000-2000 After first deployment -Winter

2012

Descope reduces baseline science mission but is above threshold science mission


4.4. Management of Reserves, Margins, and Descope Options

The PM will manage the schedule contingency and cost reserves. Using the risk list, the PM will apply reserves and margins to implement risk mitigations or deal with the risk outcome. The PM will receive concurrence from the PI and report it to ESSP. Throughout the instrument modification time, statusing allocations will be monitored by the SE Lead. Changes that affect other interfaces must be formally documented and approved via CCB by the SE, Global Hawk Project Office, DPM and PM before they are implemented. Any changes that affect science or programmatic requirements must be formally documented, requested, and approved via CCB by the PI, PM and ESSP Program Office before they are implemented. When such actions require descoping, the PI must have the concurrence of the Program Office. The allocation and release of all resources are under configuration control and are monitored by, and require concurrence of, the PI, PM and DPM. The descope options are identified in Table 4-2.



5.0. Cost and Cost Estimating Methodology

5.1 Cost Summary

The proposed PI managed investigation cost for ATTREX is $XXM (RY$) including a 15% reserve. The ATTREX investigation team prepared a grassroots cost estimate, building the budget from the bottom up, taking into account all known costs and adding reserves. Estimates include all costs associated with instrument modification for the Global Hawk, Global Hawk payload modifications, integration, flight-testing, three science deployments, and extensive data analysis and modeling of the TTL. The ATTREX investigation master schedule is used in the grass-roots estimate. The grassroots estimate assigns required resources by Work Breakdown Structure (WBS) element, which is defined in Appendix X. The team defined the WBS elements in sufficient detail to allow accurate projection of staffing and associated resources required to meet programmatic initiatives and schedules. Staffing needs were estimated by labor classification.

5.2 Cost Estimating Methodology

The ATTREX PI managed cost is based upon well-defined science requirements, assessment of modification and integration of both the instruments and Global Hawk, and the planning for three science deployed campaigns. The ATTREX followed a comprehensive grass-roots cost estimation process that included the following iterative steps:

1) Establish an investigation technical baseline;2) Develop a product and organizational level 3 WBS structure based on the AO defined level 2 WBS;3) Establish organizational responsibility for each WBS element for development and costing;4) Develop investigation schedule and define major milestones and activities;5) Establish the full set of travel for the investigation as shown in Table 5-1;6) Establish costing guidelines to ensure consistency between WBS elements and develop WBS dictionary;7) Each responsible WBS element estimates the investigation costs using the appropriate Basis of Estimate;8) Quantify the uncertainity inherent in each WBS estimate and determine cost reserve estimate that best addresses known cost and

mission risks;9) Create a roll-up of investigation costs, including reserves10) Assess cost credibility and estimating consistency among WBS elements;11) Refine costs iteratively based on review findings and modifications to the technical baseline

5.3 Reserves Level Justification

The ATTREX science investigation proposal includes a total of 15% reserve based on the total investigation. That value was crosschecked againist a reserve stratedgy assessed againist each level 2 WBS element and is shown in Table 5-2. This allows us to allocate a larger weighting in the areas of higher uncertainity for WBS 4.0 Instruments and 8.0 Integration and Test. This approach yields a reserve os $3,518K compared to the straight 15% assessment of $3,722K. This reserve analysis will also be used at each of the KDP milestones.

Another reserve assessment is to quatify the cost uncertainities of the “known unknowns” and summarized in Table 5-3. This also shows that there is still unemcumbered reserve for the “unknown unknowns”.


Table 5-1: List of Trips Used to Estimate Travel Costs

Trip Location Trip Planning Dates # Travel DaysScience Team MeetingsScience Team Meeting (ST-1) Kick-Off NASA DFRC 7/12-16/2010 5

Science Team Meeting (ST-2) Boulder 3/4-8/2013 5

Science Team Meeting (ST-3) NASA GSFC 3/31-4/4/2014 5

Science Team Meeting (ST-4) NASA ARC 3/2-6/2015 5

Quarterly ReviewsQuarterly Project Status Review (FY11-3) NASA LaRC 5/3-5/2011 3

Quarterly Project Status Review (FY12-3) NASA LaRC 5/1-3/2012 3

Quarterly Project Status Review (FY13-3) NASA LaRC 4/30-5/2/2013 3



Development Meetings

Deployment Site Visit

Hawaii, Guam,

Darwin 8/2010 14

SRR NASA ARC 9/15/2010 3

PDR NASA ARC 1/25/2011 4

Confirmation Review NASA HQ 3/1-3/2011 3

CDR NASA ARC 5/1/2011 4

Initial Instrument Integration for Winter Deployment NASA DFRC 7/1/2011

Instrument

Dependent 7 -

35

Flight Readiness Review NASA DFRC 9/13-15/2011 3

Mission Readiness Review NASA ARC 12/13-15/2011 3

Science Investigation CampaignsInstrument Integration for Winter Deployment NASA DFRC 11/28-12/9/2011 14

Winter Deployment - Guam Yigo, Guam 1/9-2/9/2012 34

Instrument De-integration for Winter Deployment NASA DFRC 2/14-17/2012 4

Instrument Integration for Fall Deployment NASA DFRC 7/30-8/10/2012 14

Fall Deployment - Hawaii Kauai 9/3-10/4/2012 34

Instrument De-integration for Fall Deployment NASA DFRC 10/9-12/2012 4

Instrument Integration for Summer Deployment NASA DFRC 5/27-6/7/2013 14

Summer Deployment - Hawaii Kauai 7/1-8/1/2013 34

Instrument De-integration for Summer Deployment NASA DFRC 8/6-9/2013 4



Table 5-2: Cost Reserves Strategy

WBS Element Cost ($K) Reserve (%) Reserve ($K)

01 Project Management 2092 10 209.2

02 Systems Engineering 589 5 29.4

03 Safety & Investigation Assurance 442 5 22.1

04 Instruments 11672 20 2334.5

05 Flight System & Services 25 0 0.0

06 Investigation Operations 2900 10 290.0

07 Ground Systems 380 10 38.0

08 Integration & Test 1297 25 324.3

09 Science Team 5413 5 270.7

Subtotal 24811 3518.1

Reserves (15%) 3722

Total Cost 28532

Table 5-3: Cost Uncertainty Assessment

Reserves Category Estimated Amount ($K) WBS

Flight Hours 350 6, 8

Fuel Surcharge 45 6

Equipment Transport 150

Instrument Modifications 4

Additional Ku Downlink Time 140 7

Global Hawk Integration

Extended Deployment

Total




APPENDICES



A. ATTREX –Cost Table FY10 FY11 FY12 FY13 FY14 FY15 Total ($K)

0

1 Project Management

181 391 404 415 435 266 2092

0

1.01 Pjt Mgt & Planning

139.2 287.8 295.9 309.6 324.4 197.2 1554.1

0

1.02 Mgt Reviews & Approvals

5 11 11 3 3 3 36

0

1.03 Deployment Mgt

0

0

1.04 Risk and Configuration Mgt

0

0

1.05 Contract Mgt

37 92 97 102 108 66 501.6

0

1.06 Reserves (bottom of Table)

0

0

2 Systems Engineering

37 92 34 0 0 0 163

0

2.01 Systems Engineering Mgt

46 107 131 71 58 14 427

0

2.02 Mission Rqmts, V&V

36.5 92.3 33.7 0.0 0.0 0.0 162.5

0

3 Safety & Investigation Assure

68 157 98 52 54 13 442

0

3.01 SMA Mgt

6

8

1

57

9

8

5

2

5

4

1

3

4

42

0

3.02 Global Hawk SMA

0

0

4 Instruments

1501.5 2365.6 2825.1 2548.1 1592.5 839.6 11672

0

4.01 CPL

144.5 354.8 379.3 360.9 146 61.6 1447

0

4.02 Ozone Photometer

62 155 234 191 139 94 875

0

4.03 UCATS

47.6 141.6 237.4 157.4 134.2 141.6 859.8

0

4.04 ULH

98.9 173.8 181.9 278.3 69.4 70.7 873



0

4.05 MMS

63 144 165 166 131 107 776

0

4.06 MTP

32 99.7 391.4 240.3 118 46.7 928.1

0

4.07 AWAS

70 200 200 200 100 20 790

0

4.08 PCRS

302.3 237.6 311.2 333.2 351.9 218.3 1754.5

0

4.09 DLH

195.2 126.9 177.8 157.2 86.2 59.7 803

0

4.10 Hawkeye

352.2 452.2 265.2 176.6 143.5 0 1389.7

0

4.11 SSFR

63.8 80 81.9 87.2 73.3 0 386.2

0

4.12 Mini-DOAS

70 200 200 200 100 20 790

0

5 Flight System & Services

8 13 0 0 2.6 1.8 25

0

5.01 Operations Concepts

8 1

3

0 0 2

.6

1.8 2

5.4

5

.02 Design & Engineering

0 0 0 0 0 0 0

5

.03 System Allocations

0

5

.04 Airspace Access Mgt

0

5

.05 Payload & Mission Mgt

0

5

.06 Ground & Flight Testing

0

0

6 Investigation Operations

0 0 1948 967 0 0 2915

0

6.01 Flt Invest & Deployment Mgt

468 255 723

I

nstrument Cryogens & Gases

10 5 15

0

6.02 Science Flight Operations

1470 707 2177

0

6.03 Flt Sys Check-out & Maint

0

0

7 Ground Systems

0 170 140 70 0 0 380

0

7.01 Mobile Operations Platforms

100 100

0

7.02 DFRC Facilities

0

0

7.03 AGE/GSE

0

0

7.04 Support Systems

70 140 70 280

0

8 Integration & Test

100 1047 100 50 0 0 1297

0

8.01 Systems I&T Mgt

0

0

8.02 Integration & Deintegration

100 900 100 50 1150

0

8.03 Test Flights

147 147

0

9 Science Team

0 0 0 0 20 20 5413

0 169 405 494 467 400 242 2177



9.01 Science Mgt

9

.02 Mission Planning

129.6 192.9 191.5 195.2 183.9 33.8 926.9

9

.03 Theory, Model, & Forecasting

213 384 481 540 463 188 2269

9

.04 Data Analysis

0 0 0 0 0 0 0

9

.05 Science Team Meetings

0 0 0 0 0 0 0

9

.06 Publications

0 0 0 0 20 20 40

S

ubtotal

1895 4236 5549 4102 2104 1141 24399

R

eserves (15%)

284 635 832 615 316 171 3660

T

otal

2179 4871 6381 4717 2420 1312 28059

B. Work Breakdown Structure (WBS)

The ATTREX Work Breakdown Structure (WBS) is the basis the of the ATTREX schedule, cost, and risk management approach. Using the Level 2 WBS categories defined in the EV-1 AO, the project has established standard level 3 WBS elements for the ATTREX Science investigation shown in Figure XX.



C. WBS Dictionary

ATTREX Work Breakdown Structure

WBS Element TitleResponsible

OrganizationWBS Dictionary

1.0 Project Management ARC

Element 1 - Project Management: The business and administrative planning, organizing, directing,

coordinating, analyzing, controlling, and approval processes used to accomplish overall project

objectives, which are not associated with specific hardware or software elements. This element

includes project reviews and documentation, and project reserves. It excludes costs associated with

technical planning and management and costs associated with delivering specific engineering,

hardware and software products.

1.1 Project Management & Planning ARC

Lead, manage, and support the overall science investigation. Supports the PI in fulfilling all

reporting duties to ESSP. Provide administrative assistance for staff including travel arrangements,

meeting arrangements, facilities management (office needs). Deployment planning activities that

include site management (survey & selection), facilities, accommodations, transportation, shipping

& logistics, communications, permits and agreements. Lead the risk management effort. Includes

creation and maintenance of Project Risk List, integrating risks from vendor risk lists as appropriate;

interfacing with the Project Business personnel for development and maintenance of the Project

Lien List. Configuration Management (CM) support to the Project Team including PI Org., Industry,

university, and other members.

1.2 Management Reviews & Approvals ARC

Provide human resources and facilities for the Project’s formal, major internal reviews. Preparation

of subsequent Board RFAs and Board reports. Cost for Standing Review Board is assumed to be

carried by ESSP.

1.3 Contract Management ARC Initiates, manages, and closes-out of all the funding vehicles to the instrument teams, theory &

modeling science teams, the Global Hawk Project Office, and services for deployment

1.4 Reserve Management ARC

All budget reserves for the Project are contained in this account. No reserves are distributed to other

WBS elements until approved. Reserves are planned as part of the Project Baseline Budget. This

also includes the funding for schedule reserves. When the decision to use reserves is made, a formal

transfer from WBS 1.4 to the appropriate WBS occurs and documents haw reserves are spent.

2.0 Systems Engineering ARC

Element 2 - Systems Engineering: The technical and management efforts of directing and controlling

an integrated engineering effort for the project. This element includes the efforts to define the

project requirements for instruments, Global Hawk platform and ground system, conducting trade

studies, the integrated planning and control of the technical program efforts of design engineering,

software engineering, specialty engineering, system architecture development and integrated test

planning, system requirements writing, configuration control, technical oversight, control and

monitoring of the technical program, and risk mitigation activities. Documentation products include

requirements documents, interface control documents (ICD), Systems Engineering Management

Plan (SEMP), and master verification and validation (V&V) plan.

2.1 Systems Engineering Management ARC

Lead the Project’s overall system architecture, definition and engineering functions as the Mission

System Engineer. Includes requirements structure, flow-down, definition, and management; defining

inter-system interfaces, Project external interfaces, and test plans; conducting top-level trade studies;

managing internal Project technical resources and technical risk mitigation. Runs the Project System

Engineering Team and manages the Project Technical Action-Item List. Also includes document

development tasks such as Project Review Plans, System Engineering Reports, Project Requirements

Documents, System Description Documents, ICDs, V&V Requirements, and Project Test Plans &

Test/Verification Matrix.



2.2Mission Requirements, Verification,

& ValidationARC

Lead the effort to define the mission requirements in response to the science requirements, and

define the requirements flowdown to the subsystems. Plan and develop the Project's end-to-end

mission scenarios. Includes developing planning and operational guidelines and constraints for the

mission; The main products are: Mission Systems Requirements Document; Mission Plan. Perform

requirements V&V on the Project Systems. Key products include the Project V&V Plan and V&V

report.

3.0 Safety & Investigation Assurance ARC/DFRC

Element 3 - Safety and Investigation Assurance: The technical and management efforts of directing

and controlling the safety and mission assurance elements of the project. This element includes

design, development, review, and verification of practices and procedures and mission success

criteria intended to assure that the platform, ground systems, mission operations, and payload(s)

meet performance requirements. This element excludes mission and product assurance efforts

directed at partners and subcontractors other than a review/oversight function, and the direct costs

of environmental testing.

3.1 SMA Management ARC

Lead and manage the overall Mission Assurance effort for the Project and provide the primary

Mission Assurance interface to the Project partners. Documentation products include: Mission

Assurance Requirements (MAR) document

3.2 Global Hawk SMA DFRC All SMA activities associated with the integrated Global Hawk

4.0 Instruments ARC

Element 4 - Instruments: This element includes all the cost of managing and implementing the

development of the instruments and their GSE (hardware & software), integration and de-

integration to the Global Hawk platform, deployment of the instrument teams. All instruments are

starting at least at a TRL 6 level but may have costs to accommodate the Global Hawk. Instrument

costs include hardware and software such as algorithm and data processing development specific to

each instrument.

4.1 Cloud Physics Lidar (CPL) GSFC

4.2 NOAA Ozone Photometer NOAA

4.3

UAS Chromatograph for

Atmospheric Trace Species

(UCATS)

4.4 UAS Laser Hygrometer (ULH)

4.5Meteorological Measurement System

(MMS)ARC

4.6Microwave Temperature Profiler

(MTP)

4.7Advanced Whole Air Sampler

(AWAS)

4.8Picarro Cavity Ringdown

Spectrometer

4.9 Diode Laser Hygrometer (DLH)

4.10 Hawkeye

4.11Solar Spectral Flux Radiometer

(SSFR)

4.12 Mini-DOAS

5.0 Flight System and Services DFRCElement 5 - Flight System and Services: The NASA Global Hawk serves as the platform for carrying



instruments and other mission-oriented equipment to the Troposphere altitude to achieve the mission

objectives. This element also includes all design, development, production, assembly, test efforts,

and associated GSE of the GH in preparation to accommodate the payload complement. The GH

platform sustaining engineering between campaigns is included in this WBS. The GH integration

and test with payloads and test flights are carried under WBS element 8. The operational science

flights and deployments are in WBS element 6.

5.1 Operations Concepts DFRCAll GH platform hardware and software modifications to accommodate instruments. This includes

modifications and development of investigation specific Ground Support Equipment (GSE).

5.2 Design & Engineering DFRC The GH platform sustaining engineering between campaigns is included in this WBS.

5.3 System Allocations DFRC

5.4 Airspace Access Management DFRC

5.5 Payload & Mission Management DFRC

5.6 Ground & Flight Testing DFRC

Provide product assurance support and staff to all GH development efforts. This includes safety,

materials and processes support, contamination control, hardware and software quality engineering,

inspection, and reliability analysis

6.0 Investigation Operations ARC/DFRC

Element 6 - Investigation Operations: The management of the development and implementation of

personnel, procedures, documentation, and training required to conduct mission operations. This

element includes tracking, commanding, receiving/processing telemetry, analyses of system status,

trajectory analysis, orbit determination, maneuver analysis, target body orbit/ephemeris updates,

and disposal of remaining end-of-mission resources. This element does not include integration and

test with the other project systems. Logistics

6.1Flight Investigation and Deployment

ManagementARC Manage the overall science campaign deployments. Systems Engineering, and Safety Mission

Investigation Assurance

6.2 Science Flight Operations DFRCDeploy, operate and return the GH platform for each of the science campaigns.

6.3Flight System Check-out and

MaintenanceDFRC

7.0 Ground Systems DFRC

Element 7 - Ground Systems: The complex of equipment, hardware, software, networks, and

mission-unique facilities required to conduct mission operations of the spacecraft systems and

payloads. This complex includes the computers, communications, operating systems, and networking

equipment needed to interconnect and host the Mission Operations software. This element includes

the design, development, implementation, integration, test, and the associated support equipment of

the ground system, including the hardware and software needed for processing, archiving, and

distributing telemetry and radiometric data and for commanding the spacecraft. Also includes the

use and maintenance of the project testbeds and project-owned facilities. This element does not

include integration and test with the other project systems and conducting mission operations.

7.1 Mobile Operations Platforms DFRC

The outfitting and modifications of the Portable Operations Center (POC) to support ATTREX

deployments. The development of a Portable Payload Operations Room (PPOR) that supports the

payload users during flight at the deployment site.

7.2 DFRC Facilities DFRC GHOC and PI Support Facilities

7.3 AGE/GSE DFRC

7.4 Support Systems DFRC The procurement of the satellite communication time, range safety, and other non-DFRC costs

8.0 Integration and Test DFRC

Element 8 - Systems Integration and Testing: This element includes the hardware, software,

procedures, and project-owned facilities required to perform the integration and testing of the

instruments, Global Hawk platform, ground systems and mission operations.

8.1 Systems I&T Management DFRCManage the instrument integration, test flights, and instrument de-integration



8.2 Integration & De-integration DFRC

Develop integration and test procedures for integration and de-integration of science instruments

onto the Global Hawk. All activities are planned to be at DFRC. This includes the development or

modification of any GSE for instrument integration.

8.3 Test Flights DFRCGlobal Hawk costs to support flight tests

9.0 Science Team ARC

Element 9 - Science: This element includes the managing, directing, and controlling of the science

investigation aspects of the Project. The costs incurred to cover the Principal Investigator, Project

Scientist, science team members, and equivalent personnel are included. Specific responsibilities

include defining the science requirements and success criteria; ensuring the integration of these

requirements with the payloads, Global Hawk Platform, ground systems, and mission operations;

providing the algorithms for data processing and analyses; participating in mission operations as

appropriate; and performing data analysis, archiving, and publication of science findings. This

element excludes hardware and software for onboard science investigative instruments/payloads.

9.1 Science Management ARC The managing and planning of science goals, objectives including success criteria.

9.2 Mission Planning ARCInitial flight concepts to achieve science measurements. Detailed science flight planning for each

campaign

9.3Theory, Data Analysis, Modeling, &

ForecastingTheory Team

Analysis of investigation instrument data and correlation to other data sets such as satellite

measurements

9.4 Science Team Meetings Theory TeamCost of travel to support the four science team meetings

9.5 Publications ARCDeveloping and submitting papers, as well as travel to conferences to present science results,

including conference fees.



D. Statement of Work (SOW)



E. Master Equipment List (MEL)


Table F-1. Derivation of Flight Hours and Associated Costs

Flight Hours Test Flights

(Hrs)

Ferry Flight

Round Trip

(Hrs)

Science (Hrs) Total (Hrs) Total ($K) WBS FY

Initial I&T 12 N/A 30 42 147 8.2 11

Winter-Guam 10 28 180 218 763 6.2 12

Fall-Hawaii 10 12 180 202 707 6.2 12

Summer-Hawaii 10 12 180 202 707 6.2 13

Subtotal 42 52 570 664 2324 -

Reserve (15%) - - - 100 349 - -

Total - - - 764 2673 - -


F. Basis of Estimate Details

WBS 1.0 Project Management, 2.0 Systems Engineering, 3.0 Safety & Investigation Assurance

NASA ARC estimated these elements by analyzing staffing loading for each element through all mission phases. Consideration was taken of task duration and level-of-effort, and required skill mix. The key personnel for project management are the PM, DPM, and Business Manager. The largest effort is at the beginning of the investigation ensuring the modification and integration of the instruments to the Global Hawk as well as the bulk of the deployment planning. After the deployments the required management tasks will be quieter. Significant effort for the Business Manager will be setting the funding for all the instrument teams, theory and modeling science team members, and Global Hawk Project Office. The funding vehicles will vary from distribution to multiple NASA centers, other federal institutions, universities, and commercial companies. Systems Engineering includes

WBS 4.0 Instruments

Each of the Instruments Teams were given guidelines and the investigation schedule and provided their estimates. They included the effort for instrument modification, integration into the Global Hawk, deployment support, and data analysis. All travel for integration, campaigns, and science team meetings were costed. Based on the GloPac experience during a campaign only 1 person is needed to be within phone access during the 30 hour flight. This allows only 2 persons per instrument to go on deployment. In order to keep things straightforward, all costs for the instruments are kept in their 4.x WBS and not spread out to other WBS elements

WBS 5.0 Flight System and Services

As the Global Hawk is an existing platform and significant modifications and repairs are not funded directly by the ATTREX Investigation, costs were not estimated in this WBS. Costs of modifications to the Global Hawk, or analyses of the aircraft compatibility with the payload suite are all carried in WBS 8.0 Integration & Test.

WBS 6.0 Investigation Operations

The cost for deployment management and travel is estimated based on per diems.

The cost rate for Global Hawk flight hours is $3500/Hr and the Global Hawk Project Office has said that this rate is expected to remain constant for the selected Earth Venture-1 investigations. (Table F-1) The reserve costs are calculated for the reserves justification but are not part of the baseline cost.

The base cost of the GH fuel is carried in the flight hour cost, however, a cost risk exists for a fuel surcharge that covers the difference for a nominal gallon of fuel at DRFC versus the cost at the deployment site. The GH consumes about 75 Gal/Hr. Assuming a fuel



surcharge of $1/Gal and the all the deployed science hours and the one way ferry hours are added together, a cost risk of ~$45K is calculated and shown in Table 4.X.

The costs for rental of office space, hangar, and networking are accounted for each deployment. It is anticipated that these costs could be significantly reduced or eliminated, If we can be stationed on a military base particularly in Guam and maybe even in Hawaii. If we are stationed in a commercial airfield these costs may be higher and represent a cost risk.

WBS 7.0 Ground System

The development of the GH Portable Operations Station is already funded and expected to be available by 3/2011. The portable version of the Payload Operations Room has been scoped out by DFRC, but has not been funded. The costs of computers, servers and design of this system to support deployed operations is covered by the investigation. The Ku downlink satellite service is purchased at a rate of $7K/Mbit/Month. With a 10 Mbit allocation the rate is $70K/Month. Between the initial integration tests and science investigations, four months of service was costed.

WBS 8.0 Integration and Test

The tasks associated with integrating the payload complement of instruments on to the Global Hawk platform. Six of the ATTREX instruments are on the GloPac Investigation slated for 1/2010, so they have already been through the initial integration. One of these istruments will be moved to a different location on the GH, but the other five will go in the same location. The other six instruments are estimated at $150K/instrument as this is their first integration on the GH platform. The integration and deintegration activities that occur at DFRC around each science deployment are considered as reflights and the cost is estimated at $50K/deployment.

The initial integration and test flights and the one science flight from DRFC have their GH flight hours cost carried in this WBS. Refer to Table XX. The cost risk for a fuel surcharge while operating out of DRFC is very low.

WBS 9.0 Science Team

Each of the theory and modeling science team members created a cost based on their anticipated involvement as well as support for research assistants or post-doctural staff. Labor rates are based upon each institution. The cost for their travel to the Science Team Meetings and their cost for publications is also contained.



G. Curriculae Vitae

Dr. Eric J. Jensen

Principal Investigator

Research Scientist, Climate and Radiation Studies NASA Ames Research Center, Moffett Field, CA [email protected]

Research and Professional Experience

Research Scientist, NASA Ames Research Center, 1997-present Research Scientist, Bay Area Environmental Research Institute, 1996-1997 Research Associate, San Jose State University, 1995-1996 Project Scientist, Scripps Institution of Oceanography, 1993-1995 NRC Associate, NASA Ames Research Center, 1990-1993

Education

Ph.D., Atmospheric Science, University of Colorado, 1985–1989 B.S., Physics, Harvey Mudd College, 1981–1985

Field Experiment Management

Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) , 1996, DC-8 flight scientist SAGE III Ozone Loss and Validation Experiment (SOLVE), 1999/2000, DC-8 flight scientist Florida Area Cirrus Experiment (CRYSTAL-FACE), 2002, project scientist Polar Aura Validation Experiment (PAVE), 2005, project scientist Water Isotope Intercomparison Flight Series (WIIF), 2005, project scientist Costa Rica Aura Validation Experiment (CRAVE), 2006, project scientist Tropical Clouds and Climate Coupling (TC4), 2007, WB-57 platform scientist

Recent Publications

Jensen, E. J., L. Pfister, T.-P. Bui, P. Lawson, and D. Baumgardner, Ice nucleation and cloud microphysical properties in tropical tropopause layer cirrus, Atmos. Chem. Phys. Discuss., 9, 20631-20675, 2009.

Jensen, E. J., et al., On the importance of small ice crystals in tropical anvil cirrus, Atmos. Chem. Phys., 9, 5519-5537, 2009. Jensen, E. J., et al., Formation of large (100 m) ice crystals near the tropical tropopause, Atmos. Chem. Phys. 8, 1621-1633, 2008. Popp, P. J., et al., Condensed-phase nitric acid in a tropical subvisible cirrus cloud, Geophys. Res. Lett., doi:10.1029/2007GL031832,

2007. Jensen, E. J., A. S. Ackerman, and J. Smith, Can Overshooting Convection Dehydrate the Tropical Tropopause Layer? , J. Geophys.

Res., in press, 2007. Jensen, E. J. and A. S. Ackerman, Homogeneous aerosol freezing in the tops of high-altitude tropical cumulonimbus clouds, Geophys.

Res. Lett., 33, doi:10.1029/2005GL024928, 2006. Smith, J., A. S. Ackerman, E. J. Jensen, and O. B. Toon, Role of deep convection in establishing the isotopic composition of water

vapor in the tropical transition layer, Geophys. Res. Lett., 33, doi:10.1029/2005GL024078, 2006. Popp, P. J., T. P. Marcy, E. J. Jensen, B. Kдrcher, D. W. Fahey, R. S. Gao, T. L. Thompson, K. H. Rosenlof, E. C. Richard, R. L. Herman, E. M. Weinstock, J. B.

Smith, R. D. May, H. Vцmel, J. C. Wilson, A. J. Heymsfield, M. J. Mahoney, and A. M. Thompson, The observation of nitric acid-containing particles in the tropical lower stratosphere, Atmos. Chem. Phys., 6, 601–611, 2006.

Jensen, E. J., J. B. Smith, L. Pfister, J. V. Pittman, E. M. Weinstock, D. S. Sayres, R. L. Herman, R. F. Troy, K. Rosenlof, T. L. Thompson, A. M. Fridlind, P. K. Hudson, D. J. Cziczo, A. J. Heymsfield, C. Schmitt, J. C. Wilson, Ice Supersaturations Exceeding 100% at the Cold Tropical Tropopause: Implications for Cirrus Formation and Dehydration, Atmos. Chem. Phys., 5, 851–862, 2005.

Jensen, E. J., and L. Pfister, Implications of Persistent Supersaturation with Respect to Ice in Cold Cirrus For Stratospheric Water Vapor, Geophys. Res. Lett., 32, doi:10.1029/2004GL021125, 2005.

Jensen, E. J., L. Pfister, T.-P. Bui, A. Weinheimer, E. Weinstock, J. Smith, J. Pittman, D. Baumgardner, M. J. McGill, Formation of a Tropopause Cirrus Layer Observed over Florida during CRYSTAL-FACE, J. Geophys. Res., 110, doi:10.1029/2004JD004671, 2005.



Fridlind, A. M., A. S. Ackerman, E. J. Jensen, A. J. Heymsfield, M. R. Poellot, D. E. Stevens, D. Wang, L. M. Miloshevich, D. Baumgardner, R. P. Lawson, J. C. Wilson, R. C. Flagan, J. H. Seinfeld, H. H. Jonsson, T. M. VanReken, V. Varutbangkul, T. A. Rissman, Evidence for the predominance of mid-tropospheric aerosols as subtropical anvil cloud nuclei, Science, 34, 718–722, 2004.

Jensen, E. J., and L. Pfister, Transport and freeze-drying in the tropical tropopause layer, J. Geophys. Res., 109, doi:10.1029/2003JD004022, 2004.

Jensen, E. J., and K. Drdla, Nitric acid concentrations near the tropical tropopause: Implications for the properties of tropical nitric acid trihydrate clouds, Geophys. Res. Lett., 29, doi:10.1029/2002GS015190, 2002b.

Jensen, E. J., O. B. Toon, A. Tabazadeh, K. Drdla, Impact of Polar Stratospheric Cloud Particle Composition, Number Density, and Lifetime on Denitrification, J. Geophys. Res., 107, doi:1029/2001JD000440, 2002a.

Santee, M. L., A. Tabazadeh, G. L. Manney, M. D. Fromm, R. M. Bevilacqua, J. W. Waters, E. J. Jensen, A Lagrangian approach to studying Arctic polar stratospheric clouds using UARS MLS HNO

3 and POAM II aerosol extinction measurements, J. Geophys. Res.,

107, 2000JD000227, 2002. Rapp, M., F.-J. Lьbken, A. Mullemann, G. E. Thomas, E. J. Jensen, Small-scale temperature variations in the vicinity of NLC: Experimental and

model results, J. Geophys. Res., 107, doi:10.1029/2001JD001241, 2002. Lin, R. F., D. O. Starr, P. J. DeMott, W. Cotton, K. Sassen, E. Jensen, B. Karcher, X. Liu., Cirrus Parcel Model Comparison Project. Phase 1:

The critical components to simulate cirrus initiation explicitly, J. Atmos. Sci., 59, 2305–2329, 2002. Jensen, E. J., et al., Prevalence of ice supersaturated regions in the upper troposphere: Implications for optically thin ice cloud

formation, J. Geophys. Res., 106, 17253–17266, 2001b. Jensen, E. J., L. Pfister, A. S. Ackerman, O. B. Toon, and A. Tabazadeh, A Conceptual Model of the Dehydration of Air Due to Freeze-

drying by Optically Thin, Laminar Cirrus Rising Slowly Across the Tropical Tropopause, J. Geophys. Res., 106, 17237–17252, 2001a.

Pfister, L., H. B. Selkirk, E. Jensen, J. Podolske, G. Sachse, M. Avery, M. R. Schoeberl, M. J. Mahoney, E. Richard, Processes controlling water vapor in the winter Arctic tropopause region J. Geophys. Res., 108, doi:10.1029/2001JD00106717, 2002.

Pfister, L., H. B. Selkirk, E. J. Jensen, M. R. Schoeberl, O. B. Toon, E. V. Browell, W. B. Grant, B. Gary, M. J. Mahoney, T. V. Bui, E. Hintsa, Aircraft observations of thin cirrus clouds near the tropical tropopause, J. Geophys. Res., 106, 9765–9786, 2001.

Stone, E. M., A. Tabazadeh, E. Jensen, H. C. Pumphrey, M. L. Santee, J. L. Mergenthaler, Onset, extent, and duration of dehydration in the Southern Hemisphere polar vortex, J. Geophys. Res., 106, 22,979–22,990, 2001.

Vay, S. A., B. E. Anderson, E. J. Jensen, G. W. Sachse, J. Ovarlez, G. L. Gregory, S. R. Nolf, J. R. Podolske, T. A. Slate, C. E. Sorenson, Tropospheric water vapor measurements over the North Atlantic during the Subsonic Assessment Ozone and Nitrogen Oxide Experiment (SONEX), J. Geophys. Res., 105, 3745–3756, 2001.

Tabazadeh, A., E. J. Jensen, O. B. Toon, K. Drdla, M. R. Schoeberl, Role of the stratospheric polar freezing belt in denitrification, Science, 291, 2591–2594, 2001.

Sandor, B. J., E. J. Jensen, E. M. Stone, W. G. Read, J. W. Waters, J. L. Mergenthaler, Upper tropospheric humidity and thin cirrus, Geophys. Res. Lett., 27, 2645-2648, 2000.



Michael T. Gaunce

Project Manager

Earth Science Project OfficeNASA Ames Research CenterM/S 245-5Moffett Field, CA 94035650-604-1266, [email protected]

Role in ATTREX Mission: Mr. Gaunce will act as the Project Manager for the mission. He implements the management content of the project, including day-to-day project planning activities, requirements, budgets, schedules, tasking, reviews, and reporting. He also leads the field campaigns for the mission.

Experience Related to the Investigation:

2002–Present: Project Manager, Earth Science Project Office, NASA Ames Research Center, Moffett Field, CA.

2000–2002: Assistant Program Director, Engineering for Complex Systems Program Office, Office of the Center Director, Ames Research Center, Moffett Field, CA.

Education:

M.S. – Purdue University, West Lafayette, Indiana, (Astronautics) – 1987

B.S. – Purdue University, West Lafayette, Indiana, (Aeronautical & Astronautical Engineering) – 1984

Additional course work completed in project management, contracting, system engineering, requirements development and management, business-government relations, team leadership, risk management, applied statistics, remote sensing, and digital image processing. Basic proficiency in Spanish, French, and German.

Relevant Awards and Honors:

2009 Ames Honor Award for CASIE Mission

2006 NASA Exceptional Achievement Medal

1997 NASA Space Flight Awareness “Silver Snoopy” Award

Numerous NASA Group Achievement Awards for leading or supporting Airborne Science Missions, including SOLVE II, INTEX-A, TCSP, INTEX-B, NAMMA, CR-AVE, TC4, ARCTAS, and SoGasEx.

Publications:

Gaunce M., Ross M., and Webster A., Streamlining Access to and Improving Utilization of NASA’s Airborne Science Fleet, Proceedings of the 33rd International Symposium on Remote Sensing of Environment, Stresa, Italy, May 2009.

Ross M., and Gaunce M., “Common Sensor Integration Requirements for NASA Research Aircraft: Preliminary Assessment and Roadmap,” Aerospace Technical Report TOR-2009(2189)-8768, December 2008.

Schoenung, S. with assistance of Gaunce, M., Earth Science Mission Requirements for Unmanned Aircraft Systems, Proceedings of the Association for Unmanned Vehicle Systems International (AUVSI) Symposium, 2006.



Dr. Leonhard Pfister

Co-I and Ch Meteorologist

Atmospheric Sciences Branch, MS 245-5NASA/Ames Research CenterMoffett Field, CA 94035-1000650-604-3183 [email protected]

Role in ATTREX Mission: Dr. Pfister will lead the Meteorology Team that provides guidance on atmospheric conditions relevant to flight planning. He will also participate directly in the flight planning process, and provide guidance during flights to maximize science return.

Experience:

1988-present: Research Atmospheric Scientist, Earth Sciences Division, NASA/Ames Research Center, Moffett Field, CA

1980-1987: Research Scientist, Space Sciences Division, NASA/Ames Research Center, Moffett Field, CA

Education:

M. I. T. (Cambridge, MA) S. B. (Earth and Planetary Science) 1972University of Washington (Seattle, WA) Ph. D. (Atmospheric Science) 1977

Publications: Pfister, L., H. B. Selkirk, D. O. Starr, K. Rosenlof, and P. Newman, A Meteorological Overview of the TC4 Mission. Submitted to J.

Geophysl Res. , 2009.Froyd, K., et al., Aerosol Composition in the Tropical Troposphere, Atmos. Chem. Phys. Discuss., 9, 9399-9456, 2009 (Co-Author)Choi, Y., et al., Characteristics of the Atmospheric CO2 signal as observed over the coterminous United States during INTEX-NA, J.

Geophys. Res., 113, doi 10.10292007/JD008899. (Co-author).Jensen, E. J., et al., Formation of large (!100 μm) ice crystals near the tropical tropopause, Atmos. Chem. Phys. 8, 1621-1633, 2008 (Co-Author).

Park, S. et al., The CO2 tracer clock for the Tropical Tropopause Layer, Atmos. Chem. Phys., 7, 3989-4000, 2007 (Co-Author).Schwarz, J. P. et al., Coatings and their enhancement of black carbon absorption in the tropical troposphere and lower stratosphere, J.

Geophys. Res.,113, doi:10.1029/2007/JD009042, 2008 (Co-Author).Jensen, E. J., J. B. Smith, L. Pfister, J. V. Pittman, E. M. Weinstock, D. S. Sayres, R. L. Herman, R.F. Troy, K. Rosenlof, T. L. Thompson, A.

M. Fridlind, P. K. Hudson, D. J. Cziczo, A. J. Heymsfield,,C. Schmitt, J. C. Wilson, Ice Supersaturations Exceeding 100% at the Cold Tropical Tropopause: Implications for Cirrus Formation and Dehydration, Atmos. Chem. Phys., 5, 851–862, 2005 (Co-author)

Jensen, E. J., and L. Pfister, Implications of Persistent Supersaturation with Respect to Ice in Cold Cirrus For Stratospheric Water Vapor, Geophys. Res. Lett., 32, doi:10.1029/2004GL021125, 2005

Jensen, E. J., L. Pfister, T.-P. Bui, A.Weinheimer, E.Weinstock, J. Smith, J. Pittman, D. Baumgardner, M. J. McGill, Formation of a Tropopause Cirrus Layer Observed over Florida during CRYSTALFACE, J. Geophys. Res., 110, doi:10.1029/2004JD004671, 2005

Jensen, E. J., and L. Pfister, Transport and freeze-drying in the tropical tropopause layer, J. Geophys. Res., 109, doi:10.1029/2003JD004022, 2004.

Jost, H., et al, In-situ observations of mid-latitude forest fire plumes deep in the stratosphere, Geophys. Res. Lett., 31, L11101,doi:10.1029/2003GL019253 ,2004 (Co-author)

Ridley, B., 2004, Convective transport of reactive constituents to the tropical and mid-latitude tropopause region: I. Observations. Atmospheric Environment, 38, 1259-1274 (Co-author)

Pfister, L. et al., Processes controlling water vapor in the Winter Arctic Tropopause Region, J. Geophys. Res., 108, SOL57-1-15, 2003.Spang, R., G. Eidmann, M. Riese, D. Offermann, P. Preusse, L. Pfister , and P.-H. Wang, CRISTA observations of cirrus clouds around

the tropopause, J. of Geophysical Research,107, pp. CRI-2-1-18, 2002.Pfister, L. et al., Aircraft Observations of Thin Cirrus Clouds near the Tropical Tropopause, J. Geophys. Res.,106,9765-9786, 2001Pickering, K. et al, Trace gas transport and scavenging in PEM-Tropics B South Pacific Convergence Zone convection, J. of Geophysical

Research, 106,.32591-32602. 2001 (Co-Author)Alexander, M. J., J. Beres, and L. Pfister, Tropical stratospheric gravity wave activity and relationships to clouds, J. of Geophysical

Research, 105, 22299-22311, 2000.Jeker, D. et al, Measurements of Nitrogen Oxides at the Tropopause -- attribution to convection and correlation with lightning, J. of

Geophysical Research, 105, 3679-3700. 2000 (co-author)Jost, H., M. Loewenstein, L. Pfister, J. Margitan, A. Chang, R. Salawitch, and H. Michelsen, Laminae in the tropical middle-

stratosphere: origin and age estimation. Geophysical Research Letters,.25, 4337-40 1998 (co-author)



Pfister, L., K. R. Chan, T. P. Bui, S. Bowen, M. Legg, B. Gary, K. Kelly, M. Profitt, and W. Starr, Gravity waves generated by a tropical cyclone during the STEP Tropical Field program: a case study, J. of Geophysical Research, Vol. 98, pp. 8611-8638, 1993.

Pfister, L., S. Scott, M. Loewenstein, S. Bowen, and M. Legg, Mesoscale disturbances in the tropical stratosphere excited by convection: observations and effects on the stratospheric momentum budget, J. of the Atmospheric Sciences, Vol. 50, pp. 1058-1075, 1993.



DR. David W. Fahey

Co-I and Flight Scientist

Earth System Research Laboratory/Chemical Sciences DivisionNational Oceanic and Atmospheric Administration (NOAA)325 Broadway R/CSD6 Boulder, Colorado 80305 USA303-497-5277, [email protected]

Professional Experience

1981–present Research Physicist, Meteorological Chem Group, NOAA Aeronomy Laboratory

Academic Background

B.S. in Physics, University of Wisconsin, Madison, WisconsinPh.D. in Physics, University of Missouri, Rolla, Missouri

Professional Honors

Recipient of the 2008 Stratospheric Ozone Protection Award from the U.S. Environmental Protection Agency (EPA) for outstanding scientific contributions to stratospheric ozone protection.

Member of the Observing Facilities Assessment Panel (OFAP), National Center for Atmospheric Research, Boulder, CO, November 2007 – present.

Congressional Hearing Witness, Committee on Transportation and Infrastructure, Subcommittee on Aviation, Chaired by Rep. Costello, Topic: Aviation and the Environment: Emissions, 6 May 2008.

Co-author of the 2007 climate science assessment of the Intergovernmental Panel on Climate Change (IPCC).

Co-recipient of the U. S. Department of Commerce Bronze Medal for Meritorious Federal Service, January 2008, for ‘For leadership in planning, preparing, and reviewing the 2006 scientific state-of-understanding update on the ozone layer for the Montreal Protocol.’

Selected Peer-reviewed Publications

Guus J. M. Velders, David W. Fahey, John S. Daniel, Mack McFarland, and Stephen O. Andersen, The large contribution of projected HFC emissions to future climate forcing, Proceedings of the National Academy of Sciences, 106, 10949-10954, doi_10.1073_pnas.0902817106, 2009.

David S. Lee, David W. Fahey, Piers M. Forster, Peter J. Newton, Ron C.N. Wit, Ling L. Lim, Bethan Owen, Robert Sausen, Aviation and global climate change in the 21st century, Atmospheric Environment, 43, 3520–3537, 2009.

P. J. Popp, T. P. Marcy, R. S. Gao, L. A. Watts, D. W. Fahey, E. C. Richard, S. J. Oltmans, M. L. Santee, N. J. Livesey, L. Froidevaux, B. Sen, G. C. Toon, K. A. Walker, C. D. Boone, and P. F. Bernath, Stratospheric correlation between nitric acid and ozone, Journal of Geophysical Research, 114, D03305, doi:10.1029/2008JD010875, 2009.

P.J. Popp, T.P. Marcy, L.A. Watts, R.S. Gao, D.W. Fahey, E.M. Weinstock, J.B Smith, R.L. Herman, R.F. Troy, C.R. Webster, L.E. Christensen, D.G. Baumgardner, C. Voigt, B. Kärcher, J.C. Wilson, M.J. Mahoney, E.J. Jensen, T.P. Bui, Condensed-phase nitric acid in a tropical subvisible cirrus cloud, Geophysical Research Letters, 34, L24812, doi:10.1029/2007GL031832, 2007.

J. R. Spackman, J. P. Schwarz, R. S. Gao, L. A. Watts, D. S. Thomson, D. W. Fahey, J. S. Holloway, J. A. de Gouw, M. Trainer, T. B. Ryerson, Empirical correlations between black carbon aerosol and carbon monoxide in the lower and middle troposphere, Geophysical Research Letters, 35, L19816, doi:10.1029/2008GL035237, 2008.

J. P. Schwarz, R. S. Gao, J. R. Spackman, L. A. Watts, D. S. Thomson, D. W. Fahey, T. B. Ryerson, J. Peischl, J. S. Holloway, M. Trainer, G. J. Frost, T. Baynard, D. A. Lack, J. A. de Gouw, C. Warneke, L. A. Del Negro, Measurement of the mixing state, mass, and optical size of individual black carbon particles in urban and biomass burning emissions, Geophys. Res. Lett., 35, L13810, doi:10.1029/2008GL033968, 2008.

R. S. Gao, S. R. Hall, W. H. Swartz3,J. P. Schwarz, J. R. Spackman, L. A. Watts, D. W. Fahey, K. C. Aikin, R. E. Shetter, and T. P. Bui, Calculations of solar shortwave heating rates due to black carbon and ozone absorption using in situ measurements, Journal of Geophysical Research, in press, 2008.



J. P. Schwarz, J. R. Spackman, D. W. Fahey, R. S. Gao, U. Lohmann, P. Stier, L. A. Watts, D. S. Thomson, D. A. Lack, L. Pfister, M. J. Mahoney, D. Baumgardner, J. C. Wilson, J. M. Reeves, Coatings and their enhancement of black-carbon light absorption in the tropical atmosphere, Journal of Geophysical Research, 113, D03203, doi:10.1029/2007JD009042, 2008.

T. P. Marcy, P. J. Popp, R. S. Gao, D. W. Fahey, E. A. Ray, E. C. Richard, T. L. Thompson, E. L. Atlas, M. Loewenstein, S. C. Wofsy, S. Park, E. M. Weinstock, W. H. Swartz, M. J. Mahoney, Measurements of trace gases in the tropical tropopause layer, Atmospheric Environment 41, 7253–7261, 2007.

R. S. Gao, J. P. Schwarz, K. K. Kelly, D. W. Fahey, L. A. Watts, T. L. Thompson, J. R. Spackman, J. G. Slowik, E. S. Cross, J.-H. Han, P. Davidovits, T. B. Onasch, D. R. Worsnop, A novel method for estimating light-scattering properties of soot aerosols using a modified single-particle soot photometer, Aerosol Science and Technology, 41, 125-135, 2007.

J. P. Schwarz, R. S. Gao, D. W. Fahey, D. S. Thomson, L. A. Watts, J. C. Wilson, J. M. Reeves, M. Darbeheshti, D. G. Baumgardner, G. L. Kok, S. H. Chung, M. Schulz, J. Hendricks, A. Lauer, B. Kärcher, J. G. Slowik, K. H. Rosenlof, T. L. Thompson, A. O. Langford, M. Loewenstein, K. C. Aikin, Single-particle measurements of midlatitude black carbon and light-scattering aerosols from the boundary layer to the lower stratosphere, Journal of Geophysical Research, 111 (D16207), doi:10.1029/2006JD007076, 2006.



Dr. Hanwant B. Singh,

Platform Scientist

Earth Science DivisionNASA Ames Research CenterM/S 245-5Moffett Field, CA 94035650-604-6769, [[email protected]; http://geo.arc.nasa.gov/sgg/singh/]

Role in ATTREX Mission: Dr. Singh will act as a Flight Scientist involved in the planning and implementation of the mission. He will be actively involved in data acquisition and analysis


Co-Mission Scientist- SONEX/POLINAT (1995)Mission Scientist – INTEX-A/ICARTT (2004)Mission Scientist- INTEX-B/MILAGRO (2006)Co-Mission Scientist –ARCTAS (2008)1985–Present: Senior Scientist, NASA Ames Research Center, Moffett Field, CA.1975–1985: Director, Atmospheric Chemistry, SRI International

Education:

Ph. D. – University of Pittsburgh, 1973B.Tech – Indian Institute of Technology (IIT)- Delhi, 1968


- NASA Exceptional Achievement & Leadership Medals (2009, 2005, 1998).- Fellow of the World Innovative Foundation (2005)- In the ISI list of 25 most cited in Geosciences- Distinguished Alumni, Indian Institute of Technology, Delhi.- Fellow of the American Geophysical Union - HJ Allen Prize for the best scientific paper (shared with M. Kanakidou, P. Crutzen, and D. Jacob).- Executive Editor of the international Journal of Atmospheric Environment (1990-present)- Frank A. Chambers Award by the Air and Waste Management Association for "outstanding achievement in the science and art of air

pollution"

Publications (sample from over 200):

Singh, H. B., Brune, W. H., Crawford, J. H., Flocke, F., and Jacob, D. J.: Chemistry and transport of pollution over the Gulf of Mexico and the Pacific: spring 2006 INTEX-B campaign overview and first results, Atmos. Chem. Phys., 9, 2301-2318, 2009.

Singh, H. B., et al., Reactive nitrogen distribution and partitioning in the North American troposphere and lowermost stratosphere, J. Geophys. Res., 112, D12S04, doi:10.1029/2006JD007664, 2007.

Singh, H. B., W. H. Brune, J. H. Crawford, D. J. Jacob, and P. B. Russell, Overview of the summer 2004 Intercontinental Chemical Transport Experiment –North America (INTEX-A), J. Geophys. Res., 111, D24S01, doi:10.1029/2006JD007905, 2006.

Jacob D. J., B. D. Field, Q. Li, D. R. Blake, J. de Gouw, C. Warneke, A. Hansel, A. Wisthaler, H. B. Singh, A. Guenther, Global budget of methanol: Constraints from atmospheric observations, J. Geophys. Res., 110, D08303, doi:10.1029/2004JD005172, 2005.

Singh, H. B., et al., Analysis of the atmospheric distribution, sources, and sinks of oxygenated volatile organic chemicals (OVOC) based on measurements over the Pacific during TRACE-P, J. Geophys. Res, 109 (D15), Art.No. D15S07 JUN 3, 2004.

Singh, H, Y. Chen, A Staudt, D. Jacob, D. Blake, B. Heikes, J. Snow, Evidence from the Pacific troposphere for large global sources of oxygenated organic compounds, Nature, 410, 1078-1081, 2001.

Singh, H. B., A. Thompson, and H. Schlager, SONEX airborne mission and coordinated POLINAT-2 activity: overview and accomplishments, Geophys. Res. Lett., 26, 3053-3056, 1999.



Tabazadeh, A, M. Z. Jacobson, H. B. Singh, O. B. Toon, Nitric acid scavenging by mineral and biomass burning aerosols, Geophys. Res. Lett., 25, 4185-4188, 1998.

Singh, H. B. et al., Low ozone in the marine boundary layer of the tropical Pacific Ocean: photochemical loss, chlorine atoms, and entrainment, J. Geophys. Res., 101, 1907-1918, 1996.

Singh, H. B., M. Kanakidou, P. Crutzen and D. Jacob, High concentrations and photochemical fate of carbonyls and alcohols in the global troposphere, Nature, 378, 50-54, 1995.

Singh, H. B. and J. F. Kasting, Chlorine-Hydrocarbon Photochemistry in the Marine Troposphere and Lower Stratosphere, J. Atm. Chem. 7, 261-285, 1988.

Singh, H. B., Reactive Nitrogen in the Troposphere, Env. Sci and Technol., 21, 320-327, 1987.

Ramanathan, V., R. J. Cicerone, H. B. Singh, J. T. Kiehl, Trace Gas Trends and Their Potential Role in Climate Change, J. of Geophys. Res., 90, 5547-5566, 1985.

Singh, H. B., and L. J. Salas, Peroxyacetyl Nitrate (PAN) in the Free Troposphere, Nature, 302, 326-329, 1983.

Singh, H. B., L. J. Salas, and R. Stiles, Methyl Halides in and over the Eastern Pacific (35°N-35°S), J. Geophys. Res., 88, 3684-3690, 1983.

Singh, H. B., and P. L. Hanst, Peroxyacetyl Nitrate (PAN) in the Unpolluted Atmosphere: An Important Reservoir for Nitrogen Oxides, Geophys. Res. Lett., 8, 941-944, 1981.

Singh, H. B., L.J. Salas, H. Shigeishi, and E. Scribner, Atmospheric Halocarbons, Hydrocarbons, and SF6: Global Distributions, Sources, and Sinks, Science, 203, 899-903, 1979.

Singh, H. B., F.L. Ludwig, and W.B. Johnson, Tropospheric Ozone: Concentrations and Variabilities in clean Remote Atmospheres, Atmos. Environ., 12, 2185-2196, 1978.

Singh, H. B., Phosgene in the Ambient Air, Nature, 264, 428-429, 1976.

Singh, H. B., D. P. Fowler, and T. O. Peyton, Atmospheric Carbon Tetrachloride: Another Man-Made Pollutant, Science, 192,1231-1234, 1976.



Dr. M. Joan Alexander

Science Team Member, Modeling and Analysis

Senior Research Scientist, NorthWest Research Associates, Colorado Research Associates Div.3380 Mitchell Lane, Boulder, CO 80301 USAPh: 303-415-9701, FAX: 303-415-9702, Email: [email protected]

Role in the Mission:

Dr. Alexander will lead modeling and analysis work on tropical atmospheric waves and their relationship to convective clouds and precipitation, including both the Global Hawk and satellite measurements. She will also play an advisory role in flight planning providing input based on experience and on interpretation of measurements in the field.

Experience related to the investigation:

2003-present, Sr. Research Scientist, NorthWest Research Associates, CoRA Division, including terms on the management council and Chair of the financial advisory committee.2003-present, Adjoint Professor, University of Colorado, Atmosphere-Ocean Sciences.1998-present, Affiliate Professor, University of Washington, Atmospheric Sciences1998-2003, Research Scientist, NorthWest Research Associates, CoRA Division.1994-1998, Research Assistant Professor, University of Washington, Atmospheric Sci.

Education:

Ph.D. Planetary & Atmospheric Sciences, University of Colorado, Boulder, CO - 1992M.S. Planetary & Atmospheric Sciences, University of Colorado, Boulder, CO - 1989B.S. Chemistry, Purdue University, West Lafayette, Indiana, 1981

Relevant Awards and Honors:International Space Science Institute, International Team Leader, 2009-2011.World Climate Research Program/SPARC Gravity Wave Initiative, Project Leader, 2007-pres.Marie-Tharp Fellow, Columbia U, Applied Mathematics and Applied Physics, 2006-07.Fellow of the American Meteorological Society, 2006.Lecturer Cambridge Summer School, Geophysical & Environmental Fluid Dynamics, 2003.Lecturer Coupling, Energetics and Dynamics of Atmospheric Regions (CEDAR), 2002. Bjerknes Lecturer, American Geophysical Union, 2000.Annual Teaching Award, University of Washington, Atmospheric Sciences, 1998.President & President-Elect Atmospheric Sciences, American Geophysical Union, 2002-2006.Member, Board on Atmospheric Science and Climate, Nat'l Academy of Sciences, 2005-2008.Atmospheric Infrared Sounder, AIRS-Science Team, 2004-present.High Resolution Dynamics Limb Sounder, HIRDLS-Aura Science Team, 1998-present.NASA Group Achievement Award, Aura Team, 2005.NASA Group Achievement Award, CRYSTAL-FACE Science Team, 2003.NASA Group Achievement Award, CAMEX-4 Science Team, 2002.NASA Group Achievement Award, POLARIS Project Team, 1998.Participant DOE/ARM Tropical Warm Pool International Cloud Experiment (TWP-ICE), 2006.

Selected Publications:

Alexander, M. J., S. D. Eckermann, D. Broutman, and J. Ma, 2009: Momentum flux estimates for South Georgia Island mountain waves in the stratosphere

observed via satellite, Geophys. Res. Lett., 36, L12816, doi:10.1029/2009GL038587.

Grimsdell, A. W., M. J. Alexander, P. T. May, and L. Hoffmann, 2009: Model study of waves generated by convection with direct validation via satellite, J.

Atmos. Sci., (accepted).

Hoffmann, L. and M. J. Alexander, 2009: Retrieval of Stratospheric Temperatures from AIRS Radiance Measurements for Gravity Wave Studies, J. Geophys.

Res.,114, D07105, doi:10.1029/2008JD011241.



Alexander, M.J., J. Gille, C. Cavanaugh, M. Coffey, C. Craig, V. Dean, T. Eden, G. Francis, C. Halvorson, J. Hannigan, R. Khosravi, D. Kinneson, H. Lee, S.

Massie, B. Nardi, A. Lambert, 2008: Global Estimates of Gravity Wave Momentum Flux from High Resolution Dynamics Limb Sounder (HIRDLS)

Observations, J. Geophys. Res., 113, D15S18, doi:10.1029/2007JD008807.

Evan, S. and M. J. Alexander, 2008: Intermediate-scale Tropical Inertia Gravity Waves observed during TWP-ICE campaign, J. Geophys. Res., 113, D14104,

doi:10.1029/2007JD009289.

Kuester, M.A., M.J. Alexander, and E.A. Ray, 2008: A model study of gravity waves over Hurricane Humberto (2001), J. Atmos. Sci., 65, 3231-3246.

Jensen, E. J., L. Pfister, T. V. Bui, P. Lawson, B. Baker, Q. Mo, D. Baumgardner, E. M. Weinstock, J. B. Smith, E. J. Moyer, T. F. Hanisco, D. S. Sayres, J. M. St.

Clair, M. J. Alexander, O. B. Toon, and J. A. Smith, 2007: Formation of Large (~100 m) Ice Crystals Near the Tropical Tropopause, Atmos. Chem. Phys.,

8, 1621-1633.

Alexander, M.J., J.H. Richter, and B.R. Sutherland, 2006: Generation and trapping of gravity waves from convection with comparison to parameterization, J.

Atmos. Sci. 63, 2963-2977.

Wang, L., M.J. Alexander, P.T. Bui, and M.J. Mahoney, 2006: Small-scale gravity waves in ER-2 MMS/MTP wind and temperature measurements during

CRYSTAL-FACE, Atmos. Chem. Phys., 6, 1091-1104.

Alexander, M. J. and P. T. May, and J. H. Beres, 2004: Gravity waves generated by convection in the Darwin Area during DAWEX, J. Geophys. Res., 109,

D20S04, doi:10.1029/2004JD004729.

Fritts, D. C. and M. J. Alexander, 2003: Gravity wave dynamics and effects in the middle atmosphere, Rev. Geophys., 41, no. 1, doi:10.1029/2001RG000106.

Holton, J. R., M. J. Alexander and M. T. Boehm, 2001: Evidence for short vertical wavelength Kelvin waves in the DOE-ARM Nauru99 radiosonde data. J.

Geophys. Res., 106, 20,125-20,129.

Alexander, M. J., J. H. Beres and L. Pfister, 2000: Tropical stratospheric gravity wave activity and relationship to clouds. J. Geophys. Res., 105, 22,299-22,309.

Alexander, M. J., 1998: Interpretations of observed climatological patterns in stratospheric gravity wave variance. J. Geophys. Res., 103, 8627-8640.

Alexander, M. J. and J. R. Holton, 1997: A model study of zonal forcing in the equatorial stratosphere by convectively induced gravity waves. J. Atmos. Sci., 54,

408-419.

Alexander, M. J. and L. Pfister, 1995: Gravity wave momentum flux in the lower stratosphere over convection. Geophys. Res. Lett., 22, 2029-2032.



Dr. Matthew J. McGill

Co-I for Cloud Physics Lidar (CPL) Data and InstrumentationResearch Scientist, NASA Goddard Space Flight CenterCode 613.1, Greenbelt, MD 20771301-614-6281 [email protected]

ROLE IN ATTREX MISSION:

Dr. McGill will be responsible for providing the Cloud Physics Lidar (CPL) instrument and will be responsible for providing CPL data (both real-time quick look

data and fully processed data) throughout the ATTREX mission.

EXPERIENCE RELATED TO THE INVESTIGATION:

1999 – Present, Principal Investigator responsible for the Cloud Physics Lidar.

2008 – Present, Principal Investigator for UAV-Cloud Physics Lidar as part of the GloPac field campaign on the Global Hawk platform.

2000 – 2005, Mission Scientist for the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission.

EDUCATION:

Ph.D., University of Michigan, Ann Arbor, Michigan (Atmospheric Science), 1991.

M.S., University of Michigan, Ann Arbor, Michigan (Atmospheric Science), 1994.

B.S., Alma College, Alma, Michigan (Physics), 1991.

RELEVANT AWARDS AND HONORS:

2009 NASA Exceptional Service Award

2000 James J. Kerley Award for Technology Commercialization and Tech Transfer

SELECTED PUBLICATIONS:

Yorks, J.E., McGill, M., Rodier, S., Vaughan, M., Hu, Y.,and Hlavka, D., “African dust and smoke influences on radiative effects in the tropical Atlantic using

CERES and CALIOP data,” Journal of Geophysical Research, 2009 (in press).

Vaughan, M.A., Liu, Z., McGill, M.J., and Obland, M.D., “On the spectral dependence of backscatter from cirrus clouds: an assessment of CALIOP’s 1064 nm

calibration using Cloud Physics Lidar measurements,” Atmospheric Chemistry and Physics, 2009, (submitted).

McGill, M.J., Vaughan, M.A., Trepte, C.R., Hart, W.D., Hlavka, D.L., Winker, D.M., and Keuhn, R., “Airborne validation of spatial properties measured by the

CALIPSO lidar,” Journal of Geophysical Research, 112, D20201, doi:10.1029/2007JD008768, 2007.

Winker, D., B. Hunt, and M. McGill, “Initial performance assessment of CALIOP,” Geophysical Research Letters, 34, doi: 10.1029/2007GL030135, 2007.

Liu, Z., Hunt, W., Hostetler, C., Vaughan, M., McGill, M., Winker, D., and Hu, Y., “Estimating random errors in backscatter lidar observations,” Applied

Optics, 45, 4437-4447, 2006.

Hlavka, D.L., Palm, S.P., Hart, W.D., Spinhirne, J.D., McGill, M.J., and Welton, E.J., “Aerosol and cloud optical depth from GLAS: results and verification for

an October 2003 California fire smoke case,” Geophysical Research Letters, 32, doi: 10.1029/2005GL023413, 2005.

Jensen, E., Pfister, L., Bui, T., Weinheimer, A., Weinstock, E., Smith, J., Baumgardner, D., and McGill, M.J., “Formation of a tropopause cirrus layer observed

over Florida during CRYSTAL-FACE,” Journal of Geophysical Research, 110, doi: 10.1029/2004JD004671, 2005.

Liu, Z., McGill, M., Hu, Y., Hostetler, C.A., Vaughan, M., and Winker, D., “Validating lidar depolarization calibration using solar radiation scattered by ice

clouds,” Geoscience Remote Sensing Letters, 1, doi: 10.1109/LGRS.2004.829613, 2004.



McGill, M.J., Li, L., Hart, W.D., Heymsfield, G.M., Hlavka, D.L., Racette, P.E., Tian, L., Vaughan, M.A., and Winker, D.M., “Combined lidar-radar remote

sensing: initial results from CRYSTAL-FACE,” Journal of Geophysical Research, 109, doi: 10.1029/2003JD004030, 2004.

McGill, M.J., “Lidar Remote Sensing,” in Encyclopedia of Optical Engineering, doi: 10.1081/E-EOE 120009862, 2003.

McGill, M.J., Hlavka, D.L., Hart, W.D., Welton, E.J., and Campbell, J.R., “Airborne lidar measurements of aerosol optical properties during SAFARI-2000,”

Journal of Geophysical Research, 108, doi: 10.1029/2002JD002370, 2003.

McGill, M.J., Hlavka, D.L., Hart, W.D., Scott, V.S., Spinhirne, J.D., and Schmid, B., “Cloud Physics Lidar: instrument description and initial measurement

results,” Applied Optics, 41, 3725-3734, 2002.



Dr. Ru-Shan Gao

Co-I for Ozone Data and Ozone InstrumentationNOAA Earth System Research Laboratory325 Broadway R/CSD 6Boulder, CO 80305303-497-5431 (voice) 303-497-5373 (fax) [email protected] (e-mail)

Role in ATTREX Mission:

Dr. Gao will lead the ATTREX Mission Ozone Team throughout the mission, including data collection and interpretation.

Research Positions:

Research Physicist, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, December 1999 to present.

Research Scientist III, Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado, and Aeronomy Laboratory, National Oceanic and

Atmospheric Administration, Boulder, Colorado, June 1992 to December 1999.

Relevant Research Experience:

Principal Investigator or Co-Principal Investigator for reactive nitrogen, ozone, and black carbon measurements in field campaigns (STRAT, POLARIS,

ACCENT, SOLVE, CRYSTAL-FACE, AVEs, TC-4, and GloPac) with the NASA Global Hawk, ER-2 and WB-57F.

Design and construction of in situ instruments for the NASA ER-2, WB-57F, and Global Hawk high-altitude aircraft.

Interpretation of the data collected in field campaigns.

Education:

Ph.D., Physics, Rice University. May 1987.M.A., Physics, Rice University. May 1985.B.S., Physics, Zhejiang University. January 1982.

Relevant Awards:

National Aeronautics and Space Administration (NASA) Group Achievement Award for participation in:

The Tropical Composition, Cloud and Climate Coupling (TC4) campaign, 2007.

The Cirrus Regional Study of Tropical Anvils and Cirrus Layers – Florida Area Cirrus Experiment (CRYSTAL-FACE) campaign, 2002.

The Photochemistry of Ozone Loss in the Arctic Region In Summer (POLARIS) campaign, 1997.

The Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft (ASHOE/MAESA) campaign, 1994.

Relevant Technical Background

Design and construction of airborne instruments for measurements of atmospheric trace gases, computer hardware for data acquisition, and high-speed, high-

voltage electronics.

Mechanical design and construction of airborne scientific instruments.

Relevant Publications:

R. S. Gao, S. R. Hall, W. H. Swartz, J. P. Schwarz, J. R. Spackman, L. A. Watts, D. W. Fahey, K. C. Aikin R. E. Shetter, P. V. Bui., Calculations of solar

shortwave heating rates due to black carbon and ozone absorption using in situ measurements, Journal of Geophysical Research, in press, 2008.

J. P. Schwarz, R. S. Gao, D. W. Fahey, D. S. Thomson, L. A. Watts, J. C. Wilson, J. M. Reeves, D. G. Baumgardner, G. L. Kok, S. H. Chung, M. Schulz, J.

Hendricks, A. Lauer, B. Kärcher, J. G. Slowik, K. H. Rosenlof, T. L. Thompson, A. O. Langford, M. Loewenstein, K. C. Aikin., Single-particle

measurements of midlatitude black carbon and lights-scattering aerosols from the boundary layer to the lower stratosphere, Journal of Geophysical Research,

111, D16207, doi:10.1029/2006JD007076, 2006.



Marcy, T.P., D.W. Fahey, R.S. Gao, P.J. Popp, E.C. Richard, T.L. Thompson, K.H. Rosenlof, E.A. Ray, R.J. Salawitch, C.S. Atherton, D.J. Bergmann, B.A.

Ridley, A.J. Weinheimer, M. Loewenstein, E.M. Weinstock, M.J. Mahoney., Quantifying stratospheric ozone in the upper troposphere using in situ

measurements of HCl, Science, 394, 261-265, 2004.

Gao, R. S., P. J. Popp, D. W. Fahey, T. P. Marcy, R. L. Herman, E. M. Weinstock, D. G. Baumgardner, T. J. Garrett, K. H. Rosenlof, T. L. Thompson, P. T. Bui,

B. A. Ridley, S. C. Wofsy, O. B. Toon, M. A. Tolbert, B. Kärcher, Th. Peter, P. K. Hudson, A. J. Weinheimer, A. J. Heymsfield., Evidence that ambient

nitric acid increases relative humidity in low-temperature cirrus clouds, Science, 303, 516-520 2004.

R. S. Gao, E. C. Richard, P. J. Popp, G. C. Toon, D. F. Hurst, P. A. Newman, J. C. Holecek, M. J. Northway, D. W. Fahey, M. Y. Danilin, B. Sen, K. C. Aikin, P.

A. Romashkin, J. W. Elkins, C. R. Webster, S. Schauffler, J. B. Greenblant, C. T. McElroy, L. R. Lait, T. P. Bui and D. Baumgardner, Observational evidence

for the role of denitrification in Arctic stratospheric ozone loss, Geophysical Research Letters, 28, 2879-2882, 2001., Geophysical Research Letters, V25,

p3323-3326, 1998.



Dr. Elliot L. Atlas

Co-Investigator for Advanced Whole Air Sampler (AWAS)Professor, University of Miami, Rosenstiel School of Marine and Atmospheric Science, Division of Marine and Atmospheric Chemistry4600 Rickenbacker CausewayMiami, FL 33149Ph: 305-421-4128 e-mail: [email protected]


Dr. Atlas will lead the effort to collect whole air samples and to analyze these samples for a wide range of trace gases.


Professor, Department of Marine and Atmospheric Chemistry, Rosenstiel School of Marine and Atmospheric Science, University of Miami, (Aug) 2003 – present.

Affiliate Scientist, National Center for Atmospheric Research, Oct., 2003 - presentSenior Scientist, National Center for Atmospheric Research, Section Head, 1999 – 2003 Stratospheric/Tropospheric Measurements Section Head, NCAR, Atmospheric Chemistry Division, 1992-2003.Scientist III, National Center for Atmospheric Research, Atmospheric Chemistry Division, 1991-1999Visiting Scientist, National Center for Atmospheric Research, Atmospheric Chemistry Division, 1989-1991Associate Research Scientist, Department of Oceanography, Texas A&M University, 1985-1991Research Scientist, Chemistry Department, Texas A&M University, 1978-1984Research Associate, Chemistry Department, Texas A&M University, 1976-1978

Education:

Antioch College, Yellow Springs, Ohio Chemistry B.S., 1970Oregon State University, Corvallis, OregonChemical Oceanography M.S., 1973Oregon State University, Corvallis, OregonChemical Oceanography Ph.D., 1975


Schauffler, S. M, E. L. Atlas, F. Flocke, R. A. Lueb, V. Stroud, W. Travnicek., Measurements of bromine containing compounds at the tropical tropopause, Geophys. Res. Lett. 25, 317–320, 1998.

Schauffler, S. M., E. L. Atlas, D. R. Blake, F. Flocke, X. Tie, R. A. Lueb, J. M. Lee, V. Stroud, W. Travnicek, Distributions of brominated organic compounds in the troposphere and lower stratosphere, J. Geophys. Res. D17, 21,513-21,536, 1999.

Dvortsov, N., M. Geller, S. Solomon, S. M. Schauffler, E. L. Atlas, and D. R. Blake, Rethinking reactive halogen budgets in the midlatitude lower stratosphere, Geophys. Res. Lett., 26 (12), 1699-1702, 1999.

Sen, B., G. B. Osterman, R. J. Salawitch, G. C. Toon, J. J. Margitan, J.-F. Blavier, A. Y. Chang, R. D. May, C. R. Webster, R. M. Stimpfle, G. P. Bonne, P. B. Voss, K. K. Perkins, J. G. Anderson, R. C. Cohen, J. W. Elkins, G. S. Dutton, P. A. Romashkin, E. L. Atlas, S. M. Schauffler and M. Loewenstein, The budget and partitioning of stratospheric chlorine during photochemistry of ozone loss in the Arctic region in summer, J. Geophys. Res., 104, 26,653 – 26,666, 1999.

Flocke, F., R. L. Herman, R. J. Salawitch, E. L. Atlas, C. R. Webster, S. M. Schauffler, R. A. Lueb, R. D. May, E. J. Moyer, K. H. Rosenlof, D. C. Scott, D. R. Blake and T. P. Bui, An examination of the chemistry and transport processes in the tropical lower stratosphere using observations of long-lived and short-lived compounds obtained during STRAT and POLARIS, J. Geophys. Res., 26,625 – 26,642, 1999.

Singh, H. B., et al., Distribution and fate of select oxygenated organic species in the troposphere and lower stratosphere over the Atlantic, J. Geophys. Res., 105, 3795-3805, 2000.

Hurst, D.F., et al., The Construction of a Unified, High-Resolution Nitrous Oxide Data Set for ER-2 Flights During SOLVE, J. Geophys. Res., 107, D20, 8271, doi:10.1029/2001JD000417, 2002.

Schauffler, S.M., E.L. Atlas, S.G. Donnelly, A. Andrews, S.A. Montzka, J.W. Elkins, D.F. Hurst, P.A. Romashkin, G. S. Dutton, and V. Stroud, Chlorine budget and partitioning during the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment (SOLVE), J. Geophys. Res. 108(D5), 4173, doi:10.1029/2001JGD002040, 2003.

Atlas, E., B. Ridley, and C. Cantrell, The Tropospheric Ozone Production Experiment (TOPSE): Introduction, J. Geophys. Res., VOL. 108, NO. D4, 8353, doi:10.1029/2002JD003172, 2003.

Rice, A. L., et al., The carbon and hydrogen isotopic compositions of stratospheric methane: Part 1. High precision observations from the NASA ER-2 aircraft, J. Geophys. Res., VOL. 108, NO. D15, 4460, doi:10.1029/2002JD003042, 2003.



Rahn, T. et al., Extreme deuterium enrichments in stratospheric molecular hydrogen and its significance for the global budget of H2, Nature, 424, 918 – 921, 2003.

Park, S., E. Atlas, and K. Boering, Measurements of nitrous oxide isotopologues in the stratosphere: The influence of transport on the apparent enrichment factors and implications for the global N2O isotope budget, JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109, D01305, doi:10.1029/2003JD003731, 2004.

Boering, K.A., T. Jackson, K. Hoag, A.S. Cole, M. Perri, M. Thiemens, and E. Atlas, Observations of the anomalous oxygen isotopic composition of carbon dioxide in the lower stratosphere and the flux of the anomaly to the troposphere, Geophys. Res. Lett., Vol. 31, No. 3, L03109, 10.1029/2003GL018451, 2004.

Ridley, B.A., et al., Convective Transport of Reactive Constituents to the Tropical and Mid-Latitude Tropopause Region: I. Observations, Atmospheric Environment, 38 (9), 1259 – 1274, 2004.

Tuck, A. F.; Hovde, S. J.; Kelly, K. K.; Reid, S. J.; Richard, E. C.; Atlas, E. L.; Donnelly, S. G.; Stroud, V. R.; Cziczo, D. J.; Murphy, D. M.; Thomson, D. S.; Elkins, J. W.; Moore, F. L.; Ray, E. A.; Mahoney, M. J.; Friedl, R. R., Horizontal variability 1–2 km below the tropical tropopause, J. Geophys. Res., Vol. 109, No. D5, D05310, 10.1029/2003JD003942, 2004.

Quack B., E. Atlas, G. Petrick, V. Stroud, S. Schauffler, D. W. R. Wallace. Oceanic bromoform- Sources for the tropical atmosphere, Geophys. Res. Lett., 31, L23S05, doi:10.1029/2004GL020597, 2004.

Quack, B., E. Atlas, G. Petrick, D. Wallace, Bromoform and dibromomethane above the Mauritanian upwelling: Atmospheric distributions and oceanic emissions, J. Geophys. Res., 112, D09312, doi:10.1029/2006JD007614, 2007.

Marcy,T.P., P. J. Popp, R. S. Gao, D. W. Fahey, E. C. Richard, T. L. Thompson, E. L. Atlas, M. Loewenstein, S. C. Wofsyf, S. Park, E. M. Weinstock, W.H. Swartz, M.J. Mahoney, Measurements of trace gases in the tropical tropopause layer, Atmospheric Environment, 41, 7253–7261, 2007.

Wilson, J. C., S-H. Lee, J. M. Reeves, C. A. Brock, H. H. Jonsson, B. G. Lafleur, M. Loewenstein, J. Podolske, E. Atlas, K. Boering, G. Toon, D. Fahey, T. P. Bui, G. Diskin, F. Moore, The establishment of steady-state aerosol distributions in the extra-tropical, lower stratosphere and the processes that maintain them. Atmos. Chem. Phys., 8, 6617-6626, 2008.

Engel, A. , T. Möbius, H. Bönisch, U. Schmidt, R. Heinz, I. Levin, E. Atlas, S. Aoki, T. Nakazawa, S. Sugawara, F. Moore,, D. Hurst,, J. Elkins, S. Schauffler. Long term evolution in the age of air: no changes in the stratospheric circulation observable. Nature Geoscience 2, 28-31 (14 December 2008) doi:10.1038/ngeo388.

Leung, L. et al., Large and unexpected enrichment in stratospheric 13C18O16O and its meridional variation. Proc.Nat’l Acad. Sciences, July 14, 2009 vol. 106 no. 28 11496-11501, 2009.

Hossaini, R. M.P. Chipperfield, B.M. Monge-Sanz, N.A.D. Richards, E. Atlas, and D.R. Blake, Bromoform and Dibromomethane in the Tropics: A 3-D model study of chemistry and transport, Atmos. Chem. Phys. Discuss., 9, 16811-16851, 2009.



Dr. James W. Elkins

Co-I for UCATS instrument.

Supervisory Physicist, NOAA/ESRL, Global Monitoring Division(GMD)

325 Broadway, Boulder, Colorado 80305

Phone: (303) 497-6224, E-mail [email protected]

ROLE IN VENTURE CLASS MISSION:

Dr. Elkins will lead the UCATS team that measures ozone, water vapor, and two airborne gas chromatographic channels during the integration and field operation. He coordinates the calibration, operations, and data comparison between UCATS and other ground base, satellite, and aircraft instruments.


1986 – Present, P.I. of ACATS, LACE, PANTHER, and UCATS airborne chromatographs, Halocarbons and other Atmospheric Trace Species Group, Chief, NOAA/ESRL/GMD

1979 – 1985, Physicist, Atmospheric Trace Gas Standards, NIST, formerly NBS.

EDUCATION:

Ph.D. – Harvard University, Cambridge, Massachusetts (Applied Physics) - 1979

M. S. – Harvard University, Cambridge, Massachusetts (Applied Physics) - 1975

B. A. – University of Virginia, Charlottesville, Virginia (Physics – High Honors) – 1974

RELEVANT AWARDS AND HONORS:

DoC Silver Medal Award for the Annual Greenhouse Gas Index 2008

(AGGI) with Dave Hofmann and others

Nobel Peace Prize, Member of IPCC 2006 Report Team, 2008

shared with former VP Al Gore

EPA Team Award for Protection of the Ozone Layer 2007

DoC Bronze Award for the NOAA UAS Demo team 2006

NOAA Outstanding Scientific Papers of the Year (11 papers) 95-02, 05-07, 09

SELECTED PUBLICATIONS:Engel, A. T. M., H. Bönisch, U. Schmidt, R. Heinz, I. Levin, E. Atlas, S. Aoki, T. Nakazawa, S. Sugawara, F. Moore, D. Hurst, J. Elkins, S.

Schauffler, A.Andrews, K.Boering. Age of stratospheric air unchanged within uncertainties over the past 30 years. Nature Geoscience, doi: 10.1038/NGEO388, 2008.

Montzka, S.A., P. Calvert, B. Hall, J.W. Elkins, P. Tans, and C. Sweeney, On the global distribution, seasonality, and budget of atmospheric carbonyl sulfide (COS) and some similarities to CO2, J. Geophys. Res., 112, D09302, doi:10.1029/2006JD07665, 2007.

Fahey, D. W., J. H. Churnside, J. W. Elkins, A. J. Gasiewski, K. H. Rosenlof, S. Summers, M. Aslaksen, T. A. Jacobs, J. D. Sellars, C. D. J., L., & C. Freudinger, and M. Cooper, Altair Unmanned Aircraft System Achieves Demonstration Goals. EOS, 87, 20, 197,201, 2006.

D.F. Hurst, J. C. Lin, P.A. Romashkin, B.C. Daube, C. Gerbig, D.M. Matross, S.C. Wofsy, B. D. Hall, and J.W. Elkins. (2006). Continuing global significance of emissions of Montreal Protocol-restricted halocarbons in the United States and Canada. Journal of Geophysical Research, 111, D15302, doi: 10.1029/2005JD006785, 2006.

Montzka, S. A., J. H. Butler, J. W. Elkins, T. M. Thompson, A. D. Clarke and L. T. Lock, Present and future trends in the atmospheric burned of ozone-depleting halogens, Nature, 398, 690-694, 1999.



Wamsley, P. R., J. W. Elkins, et al., Distribution of halon-1211 in the upper troposphere and lower stratosphere and the 1994 total bromine budget, J. Geophys. Res., 103, (D1), 1513-1526, 1998.

Volk, C. M., Elkins, J. W., Fahey, D. W., Dutton, G. S., Gilligan, J. M., Loewenstein, M., et al. Evaluation of source gas lifetime from stratospheric observations. Journal of Geophysical Research, 102(D21), 25,543-25,564, 1997.

Volk, C. M., Elkins, J. W., Fahey, D. W., Salawitch, R. J., Dutton, G. S., Gilligan, J. M., et al., Quantifying transport between the tropical and mid-latitude lower stratosphere. Science, 272, 1763-1768, 1996

Elkins, J. W. et al., Airborne gas chromatograph for in sit u measurements of long-lived species in the upper troposphere and lower stratosphere, Geophys. Res. Lett., 23(4) , 347-350, 1996.

Elkins, J. W., T. M. Thompson, T. H. Swanson, J. H. Butler, B. D. Hall, S. O. Cummings, D. A. Fisher and A. G. Raffo, Decrease in the growth rates of atmospheric chlorofluorocarbons 11 and 12, Nature, 364, 780-783, 1993.



Dr. Steven C. Wofsy

Co-I for Picarro Cavity Ringdown Spectrometer (PCRS)

Harvard University, Room 100A, Pierce Hall, 29 Oxford St., Cambridge, MA 02138.Telephone: 617-495-4566; FAX 617-495-4551; [email protected]

Education:

University of Chicago, B.S., Chemistry, 1966; Harvard University, Cambridge, MA. Ph.D. in Chemistry, 1971; Harvard University – DEAS and Smithsonian Astrophysical Observatory, postdoctoral in atmospheric chemistry, 1971-1973.

Professional Experience:

Harvard University, School of Engineering and Applied Science, Department of Earth and Planetary Sciences:

February, 1995-present Professor, Atmospheric and Environmental Sciences .September, 2003-2006 . Associate Dean, Faculty of Arts and Sciences, Harvard UniversityJuly, 1982 to February, 1995. Senior Research Fellow (Harvard DEAS).July 1977 to June 1982. Associate Professor of Atmospheric Chemistry, (Harvard DEAS).September 1973 to June 1977. Harvard DEAS, Lecturer/Res. Fellow, Atmospheric Chemistry

Committees:

NASA Earth System Science and Applications Advisory Committee 1995-2000 (chair, 1997-99);

NASA Advisory Council, 1997-99;

Carbon Cycle Science Plan Working Group, co-chair, 1998-1999; North American Carbon Program writing group, chair, 2001-2003;

IPCC Working Group I, lead author, carbon cycle 2005-2006.

Educational Activities:

Educational Policy Committee, Faculty of Arts and Sciences, 2006; Director of Undergraduate Studies, Earth and Planetary Sciences, 2006-present; Lead author, Annenberg Foundation school curriculum, “A Habitable Planet”, Ch. 2, 2006-2007.

Aircraft Missions (> 1200 hours total):

Stratospheric (ER-2): SPADE, ASHOE, STRAT (1992-96, PI for CO2 measurements on the ER-2; Mission Scientist, SPADE and STRAT), POLARIS, SOLVE (PI for ER-2 and OMS CO2); TC4 WB-57 Platform Scientist; START08 (PI for mission and QCLS, NCAR GV)

Tropospheric: COBRA (PI for 1999-2004, CO2 and CO on Citation II and King Air, plus overall mission intiator and director); HIPPO (PI for mission and QCLS, NCAR GV).

Selected Publications

Bakwin, P.S., S. C. Wofsy, and S.M. Fan, and D. R. Fitzjarrald, Measurements of NOx and NOy Concentrations and Fluxes Over Arctic Tundra. J. Geophys. Res., 97, 16,545-16,558, 1992.

Chou, W., S. C. Wofsy, R. C. Harriss, J. C. Lin, C. Gerbig, and G. Sachse, Net fluxes of CO2 in Amazônia from aircraft data, J.Geophys. Res. 107 (D22), 4614, 10.1029/2001JD001295, 2002.

Emmons, L. K., G.G. Pfister, D.P. Edwards, J.C. Gille, G. Sachse, D. Blake, S. Wofsy, C. Gerbig, D. Matross, P. Nédéléc, MOPITT 1 validation exercises during Summer 2004 field campaigns over North America, J. Geophys.. Res.-Atmospheres 112 (D12): Art. No. D12S02 MAR 22 2007.

Gerbig, C., J. C. Lin, S. C. Wofsy, B. C. Daube, A. E. Andrews, B. B. Stephens, P. S. Bakwin, and C. A. Grainger, Towards constraining regional scale fluxes of CO2 with atmospheric observations over a continent: 2. Analysis of COBRA data using a receptor oriented framework, J. Geophys. Res. 108,. D24, 4757 (27 pp) , 2003.



Matross, D.M., A. E. Andrews, M. Pathmathevan, C. Gerbig, J. C. Lin, S. C. Wofsy, B. C. Daube, E. W. Gottieb, V. Y. Chow, J. T. Lee, C. Zhao, P. S. Bakwin, J. W. Munger, and D. Hollinger, Estimating regional carbon exchange in New England and Quebec by combining atmospheric, ground-based, and satellite data, Tellus Ser. B-Chem. phys. met. 58 (5): 344-358 NOV 2006.

Miller, S. M., D. M. Matross, A. E. Andrews, D. B. Millet, M. Longo, E. W. Gottlieb, A. I. Hirsch, C. Gerbig, J. C. Lin, B. C. Daube, R. C. Hudman, P. L. S. Dias, V. Y. Chow, and S. C. Wofsy, Sources of carbon monoxide and formaldehyde in North America determined from high-resolution atmospheric data, Atmos. Chem. Phys. Discuss., 8, 11395-11451, 2008.

Park, S., R. Jimenez, B. C. Daube, L. Pfister, T. J. Conway, E. W. Gottlieb, V. Y. Chow , D. J. Curran , D. M. Matross, A. Bright , E. L. Atlas , T. P. Bui, R.-S. Gao, C. H. Twohy, and S. C. Wofsy, The CO2 tracer clock for the Tropical Tropopause Layer Atmos. Chem. Phys., 7, 3989–4000, 2007.

Saleska, S. R.S. D. Miller, D. M. Matross, M. L. Goulden, S. C. Wofsy, H. R. da Rocha, P.B. de Camargo, P. Crill, B. C. Daube, H. C. de Freitas, L. Hutyra, M. Keller, V.W. H. Kirchhoff, M. Menton, J. W. Munger, E. H. Pyle, A. H. Rice, H. Silva, Carbon in Amazon forests: unexpected seasonal fluxes and disturbance-induced losses, Science 302, 1554-1557, 2003.



Dr. Robert L. Herman

Co-I for Water Vapor Data Research Scientist, Jet Propulsion Laboratory, Section 3282Mail Stop 183-4014800 Oak Grove DrivePasadena, CA 91109(818) 393-4720 [email protected]

ROLE IN ATTREX MISSION:

Dr. Herman will provide in-situ water vapor measurements from the JPL Laser Hygrometer on the Global Hawk.


1999 - Present, Principal Investigator, JPL Laser Hygrometers2001 - Present, Research Scientist, Jet Propulsion Laboratory1999 - 2001, Scientist, Jet Propulsion Laboratory

EDUCATION:

Ph.D. (Geochemistry), California Institute of Technology (1998).M.S. (Geochemistry), California Institute of Technology (1993).B.A. (Chemistry – General Honors), University of Chicago (1991).


Read, W. G., et al., “EOS Aura Microwave Limb Sounder Upper Tropospheric and Lower Stratospheric Humidity Validation,” J. Geophys. Res., 112, D24S35, doi:10.1029/2007JD008752, 2008.

Popp, P. J., Herman, R. L, et al., “Condensed-phase nitric acid in a tropical subvisible cirrus cloud,” Geophys. Res. Lett., 34, L24812, doi:10.1029/2007GL031832, 2007.

Richard, E. C., Herman, R. L, et al., “High-resolution airborne profiles of CH4, O3 and water vapor near tropical Central America in late January to early February 2004,” J. Geophys. Res., 111, D13304, doi:10.1029/2005JD006513, 2006.

Gao, R. S., Fahey, D. W., Popp, P. J., Marcy, T. P., Herman, R. L, Weinstock, E. M., et al. Measurements of relative humidity in a persistent contrail. Atmospheric Environment, 40(9), 1590-1600, 2006.

Popp, P. J., Herman, R. L, et al., “The observation of nitric acid-containing particles in the tropical lower stratosphere,” Atmos. Chem. Phys. Discus., 6, 601-11, 2006.

Heymsfield, A. J., et al., “Ice Microphysical observations in Hurricane Humberto: comparison with non-hurricane ice cloud layers,” J. Atmos. Sci., 63(1), 288-308, 2006.

Jensen, E., Herman, R. L, et al., “Ice Supersaturations Exceeding 100% at the Cold Tropical Tropopause: Implications for Cirrus Formation and Dehydration,” Atmos. Chem. Phys. Discus.,4, 7433-62, 2004.

Gettelman, A., Herman, R. L, et al., “Validation of Aqua satellite data in the upper troposphere and lower stratosphere with in-situ aircraft,” Geophys. Res. Lett., 31(22), L22107, doi: 10.1029/2004GL020730, 2004.

Garrett, T. J., Herman, R. L, et al., “Evolution of a Florida cirrus anvil,” J. Atmos. Res., 62, 2353-72, 2005.

Gao, R. S., Popp, P. J., Fahey, D. W., Marcy, T. P., Herman, R. L., Weinstock, E. M., et al. Evidence that nitric acid increases relative humidity in low-temperature cirrus clouds. Science, 303(5657), 516-520, 2004.

Herman, R. L., and Heymsfield, A. J., “Aircraft icing at low temperatures in Tropical Storm Chantal (2001),” Geophys. Res. Lett., 30(18), 1955, doi:10.1029/2003GL017746, 2003.

Herman, R. L, et al., “Hydration, dehydration, and the total hydrogen budget of the 1999-2000 winter Arctic stratosphere,” J. Geophys. Res., 108(D5), doi:10.1029/2001JD001257, 2003.



Glen Diskin

Co-I for DLH

LARC

[email protected]

757-864-6268



Dr. R. Paul Lawson

Co-I for HawkeyeSPEC Incorporated3022 Sterling CircleBoulder, CO 80301(303)-449-1105(303)-449-0132 (fax)[email protected]

ROLE IN MISSION:

Dr. Lawson will lead the SPEC Instrumentation and Data Analysis Teams throughout the missions, including installation of the Hawkeye on the Global Hawk, participation in the field campaigns, data processing and scientific analysis.


Dr. Lawson has been heavily involved in the development of instrumentation and analysis of meteorological data for more than three decades. He has participated in over 50 meteorological field programs as scientist and/or pilot including:

1989 – Present: Senior Scientist/President: SPEC Incorporated1977 – 1980: Learjet Pilot/Scientist during HIPLEX 1981: Pilot of the NCAR instrumented sailplane and scientist during the CCOPE 1992: Flight Scientist during CASP II field programs1995: Scientist during the Canadian Freezing Drizzle Experiment1995: Flight Scientist for the Small Cumulus Microphysics Study 1996: Principal investigator for the NASA DC-8 SUCCESS field program.1998: Principal investigator for the NASA FIRE.ACE field program. 1998: Learjet Pilot and Principal investigator for the NASA TRMM TEFLUN-A field program. 1998-1999: Learjet Pilot and Scientist for the NASA EOS cirrus studies. 1999-2000: Learjet Pilot and Scientist for the Alliance Icing Research Study (AIRS) in Ottawa, Ontario2002: Principal Investigator for the NASA CRYSTAL-FACE field program2000 – 2006: Principal Investigator and Learjet Pilot for the NSF Wave Cloud Studies 2003 – 2006: Principal Investigator and Learjet Pilot for the NASA Cirrus Cloud Studies2003 – 2006: Principal Investigator NSF Ice Crystal Studies at the South Pole2004: Principal Investigator and Learjet Pilot for the NASA MidCiX field program2006: Principal Investigator for the NASA CR-AVE field program2007: Principal Investigator and Learjet pilot for the NSF ICE-L Wave Cloud field program2006: Principal Investigator for the NASA NAMMA project2007: Principal Investigator for the NASA TC4 project2008: Principal Investigator for the NSF Tethered Balloon project in Svalbard2008: Principal Investigator for the DOE ISDAC project2009: Principal Investigator for the DOE SPARTICUS project

EDUCATION:

B. S. Electrical Engineering - Michigan State University, East Lansing, Michigan - 1969M.S. Atmospheric Science - University of Wyoming, Laramie, Wyoming - 1972Ph.D. Atmospheric Science - University of Wyoming, Laramie, Wyoming – 1988


Baker, B. A., and R. P. Lawson, In situ observations of the microphysical properties of wave, cirrus and anvil clouds. Part 1: Wave clouds, J. Atmos. Sci., 63, 3160-3185, 2006.

Evans, K. F., R. P. Lawson, P. Zmarzly, D. O'Connor, and W. J. Wiscombe, In situ cloud sensing with multiple scattering lidar: Simulations and demonstration, J. Atmos. Ocean Technol., 20, 1505-1522, 2003.

Evans, K. F., D. O'Connor, P. Zmarzly, and Jensen, E. J., In situ cloud sensing with multiple scattering lidar: Design and validation of an airborne sensor, J. Atmos. Ocean Technol., 23, 1068-1081, 2006.



Lawson, R. P., B. Pilson, B. Baker, Q. Mo, E. Jensen, L. Pfister, and P. Bui, Aircraft measurements of microphysical properties of subvisible cirrus in the tropical tropopause layer, Atmos. Chem. Phys., 8, 1609-1620, 2008.

Lawson, R. P., and B. A. Baker, Improvement in determination of ice water content from two-dimensional particle imagery. Part II: Applications to collected data, J. Appl. Meteorol., 45, 1292-1303, 2006.

Lawson, R. P., B. A. Baker, B. Pilson, Q. Mo, In Situ observations of the microphysical properties of wave, cirrus and anvil clouds. Part II: Cirrus Clouds, J. Atmos. Sci., 63, 3186-3203. 2006.

Lawson, R. P., B. A. Baker, P. Zmarzly, D. O’Connor, Q. Mo, J.-F. Gayet, and V. Shcherbakov, Microphysical and optical properties of ice crystals at South Pole Station, J. Appl. Meteorol., 45, 1505-1524, 2006.

Lawson, R. P., D. O’Connor, P. Zmarzly, K. Weaver, B. A. Baker, Q. Mo, and H. Jonsson, The 2D-S (Stereo) Probe: Design and Preliminary Tests of a New Airborne, High-Speed, High-Resolution Particle Imaging Probe, J. Atmos. Oceanic Technol., 23, 1462-1477, 2006.

Lawson, R.P., B.A. Baker, C.G. Schmitt and T.L. Jensen, An overview of microphysical properties of Arctic clouds observed in May and July during FIRE.ACE, J. Geophys. Res., 106, 14,989-15,014, 2001.

Lawson, R. P., L. J. Angus, A. J. Heymsfield, Cloud particle measurements in thunderstorm anvils and possible weather threat to aviation, J. of Aircraft, 35, 113-121, 1998.

Lawson, R. P. and R. H. Cormack, Theoretical design and preliminary tests of two new particle spectrometers for cloud microphysics research, Atmos. Res., 35, 315-348, 1995.



Dr. Peter Pilewskie

Co-I for Solar, IR radiometers


[email protected]

303-492-5724



Dr. T. Paul Bui

Co-I for Meteorological Measurement System Instrument (MMS)Atmospheric Chemistry and Dynamics BranchNASA Ames Research Center, MS 245-5, Moffett Field, CA 94035-1000(650) 604-5534, [email protected]

Role in ATTREX Mission

Mr. Paul Bui will lead the instrument team to measure in situ temperature, winds, and turbulence on the Global Hawk platform.

Experience:

NASA-Ames Research Center, Moffett Field, CA1995-Present: Principal Investigator, Meteorological Measurement System1984-1994: Lead Engineer, Meteorological Measurement SystemPrincipal Investigator for the Following Airborne Campaigns:STRAT (Stratospheric Tracers and Transport, 1995-1996)SONEX (Subsonic Assessment, Ozone and Nitrogen Oxide Experiment, 1997)POLARIS (Photochemistry of Ozone Loss in the Arctic Region in Summer, 1997)CAMEX-3/4 (Convection and Atmospheric Moisture Experiment, 1998, 2001)SOLVE (Sage Ozone Loss Validation Experiment, 2000)CRYSTAL-FACE (Cirrus Regional Study of Tropical Anvils and Cirrus Layers, 2002)MidCix (Middle Latitude Cirrus Experiment, 2004)AVE (AURA Validation Experiment: June2005_AVE and CRAVE_2006)NAMMA (NASA African Monsoon Multidisciplinary Activities, 2006)TC4 (Tropical Composition, Cloud, and Climate Coupling Experiment, 2007)NOVICE (Newly Operating Validated Instrument Comparison Experiment, 2008)

Education:

Candidate for M. S. Meteorology, San Jose State UniversityB. S. Electrical Engineering, Massachusetts Institute of Technology, 1984Senior Thesis: X-ray Satellite Development, Astronomy Dept.

Awards:

NASA Exceptional Engineering Achievement

Relevant Publications

Gaines, S. E., S. W. Bowen, R. S. Hipskind, T.P. Bui, and K. R. Chan: Comparisons of the NASA ER-2 meteorological measurement system with radar tracking and radiosonde data, J. Atmos. Ocean. Tech., 9, 210-225, 1992.

Scott, S. G., T.P. Bui, K. R. Chan, and S. W. Bowen: The meteorological measurement system on the NASA ER-2 aircraft, J. Atmos. Ocean. Tech., 7, 525-540, 1990.

Chan, K. R., L. Pfister, T.P. Bui, S. W. Bowen, J. Dean-Day, B.L. Gary, D.W. Fahey, K.K. Kelly, C.R. Webster, and R. D. May: A case study of the mountain lee wave event of January 6 1992, Geophys. Res. Letters, 20, 2551-2554, 1993.

Bui, T. P., S. Bowen, C. Chang, J. DeanDay, L. Pfister, R. Castenada, P. Shulman: Evaluating WB-57F and ER-2 MMS measurement confidence, CRYSTAL-FACE Science Meeting at Salt Lake City, Feb. 2003



Dr. Michael J. Mahoney

Co-I for Microwave Temperature Profiler (MTP) MeasurementsMTP Principal InvestigatorJet Propulsion Laboratory, MS 246-102 Phone: (818)-354-5584California Institute of Technology Fax: (818)-393-00254800 Oak Grove Drive Email: [email protected], CA 91101-8099 Web Site: http://mtp.jpl.nasa.gov/


Dr. Mahoney will lead the Microwave Temperature Profiler (MTP) team in all aspects of the ATTREX campaign. This will include calibration of the MTP in our laboratory before and after the campaigns, supporting the instrument in the field, performing the data calibration, analysis and archiving after each campaign, and attending science team meetings.


1998-Present Microwave Temperature Profiler (MTP) Principal Investigator, JPL/Caltech

1996-1998 Submillimeter Technologist and Research Scientist, JPL/Caltech

1992-1996 Ground-Based Microwave Applications Group Supervisor, JPL/Caltech

1990-1991 Acting Manager, Precision Segmented Reflectors Program, JPL/Caltech

1987-1990 Systems Engineer, Precision Segmented Reflectors Program, JPL/Caltech

1987-1996 Design Team Manager for LDR, SMIM, and FIRST, JPL/Caltech

1976-1987 Resident Director, Clark Lake Radio Observatory, U. Maryland (College Park)

Education:

Ph. D. - University of British Columbia, Vancouver, Canada (Physics) - 1976

M. Sc. - University of British Columbia, Vancouver, Canada (Physics) - 1972

B. Sc. - University of British Columbia, Vancouver, Canada (Physics - Honors) - 1968


1999 NOAA Outstanding Paper Award

1998-2008 Eight (8) NASA Group Achievement Awards

2000-2008 Two (2) NASA Certificates of Recognition

2008 NASA Exceptional Achievement Medal


Corti, T, B. P. Luo, M. de Reus, D. Brunner, F. Cairo, M. J. Mahoney, G. Martucci, R. Matthey, V. Mitev, F. H. dos Santos, C. Shiller, G. Shur, N. M. Sitnikov, N. Spelten, H. J. Vossing, S. Borrmann, and T. Peter, “Unprecedented evidence for deep convection hydrating the tropical stratosphere,” Geophysical Research Letters, 35, L10810, doi:10.1029/2008GL033641, 2008.

Nielsen-Gammon, John W., Christina L. Powell, M. J. Mahoney, Wayne Angevine, Christoph Senff, Allen White, Carl Berkowitz, Christopher Doran, and Kevin Knupp, “Multi-Sensor Estimation of Mixing Heights Over a Coastal City,” Journal of Applied Meteorology and Climatology, 47(1), 27, January 2008.

Halverson, J., M. Black, S. Braun, D. Cecil, M. Goodman, A. Heymsfield, G. Heymsfield, R. Hood, T. Krishnamurti, G. McFarquhar, M.J. Mahoney, J. Molinari, R. Rogers, J. Turk, C. Velden, D.-L. Zhang, E. Zipser, R. Kakar, “NASA's Tropical Cloud Systems and Processes (TCSP) Experiment: Investigating Tropical Cyclogenesis and Hurricane Intensity Change,” BAMS, 867-882, June 2007.

Eckermann, Stephen D., Dörnbrack, Andreas, Vosper, Simon B., Flentje, Harald, Mahoney, M. J., Bui, T. Paul, Carslaw, Kenneth S., “Mountain Wave–Induced Polar Stratospheric Cloud Forecasts for Aircraft Science Flights during SOLVE/THESEO 2000,” Weather and Forecasting, 21(1), 42-68, 2006.



Popp, P. J., T. P. Marcy, E. J. Jensen, B. Karcher, D. W. Fahey, R. S. Gao, T. L. Thompson, K. Rosenlof, E. C. Richard, R. L. Herman, E. M. Weinstock, J. B. Smith, R. D. May, J. C. Wilson, A. J. Heymsfield, M. J. Mahoney, and A. M. Thompson, “The observation of nitric-acid containing particles in the tropical lower stratosphere,” Atmos. Chem. Phys. Discuss., Vol. 5, pp 10097-10124, 18-10-2005.

Wang, Ling, M. Joan Alexander, Thaopaul V. Bui, and Michael J. Mahoney, “Small-Scale Gravity Waves in ER-2 MMS/MTP Wind and Temperature Measurements during CRYSTAL-FACE,” Atmos. Chem. Phys. Discuss., Vol. 5, 11377-11412, 2005.

Marcy, T. P., D.W. Fahey, R. S. Gao, P.J. Popp, E. C. Richard, T. L. Thompson, K. H. Rosenlof, E. A. Ray, R. J. Salawitch, B. A. Ridley, M. Lowenstein, J. C. Wilson, E. M. Weinstock, M. J. Mahoney, R. L. Herman, “Quantifying Stratospheric Ozone in the Upper Troposphere Using in situ Measurements of HCl,” Science, 9 April 2004: 261-265.

Ridley, B., E. Atlas, H. Selkirk, L. Pfister, D. Montzka, S. Donnelly, V. Stroud, E. Richard, K. Kelly, A. Tuck, T. Thompson, C. Brock, C. Wilson, D. Baumgardner, M. Mahoney, R. Herman, R. Freidl, J. Elkins, F. Moore, M. Ross, D. Anderson, “Convective transport of reactive constituents to the tropical and mid-latitude tropopause region: I. Observations,” Atmos. Environ., 38, 1259-1274, 2004.

Pan, L. L., W. J. Randel, E. Browell, B. G. Gary, M. J. Mahoney, and E. J. Hintsa, “Definitions and sharpness of the extratropical tropopause: A trace gas perspective,” J. Geophys. Res., 109, D23103, doi:10.1029/2004JD004982.

Dornbrack, A., T. Birner, A Fix, H. Flentje, A. Meister, H. Schmid, E. Browell, M. J. Mahoney, “Evidence for inertia-gravity waves forming polar stratospheric clouds over Scandinavia,” J. Geophys. Res., 107(D20), 8287, doi:10.1029/2001JD000452, 2002.

Murphy, D. M., D. S. Thomson, and M. J. Mahoney, “In Situ Measurement of Organics, Meteoritic Material, Mercury, and Other Elements in Aerosols at 5 to 19 Kilometers,” Science, 282, 1664-1669, 1998.



Jochen Peter Stutz

University of California, Los AngelesDepartment of Atmospheric Sciences7127 Math Science BuildingLos Angeles, CA 90095-1565

Tel: 310- 825-5364

Fax: 310-206-5219

email: [email protected]

Role in GMT2 Mission: Dr. Stutz will act as PI for the Mini-DOAS instrument.


20 years experience in the development of DOAS instruments and analysis software. Dissemination of the principles of DOAS via a recently published textbook [Platt and Stutz, 2008]

Participation in multiple collaborative field studies, for example: SHARP 2009, Houston; GSHOX 2007 and 2008, Summit, Greenland; CalHal 2006, Malibu: TRAMP/TEXAQS 2006, Houston, TX; MIRAGE 2006, Mexico City; ICARTT 2004, Gulf of Maine; NAOPEX 2002, Boston, MA; Phoenix Ozone Experiment 2001, AZ; VTMX 2000, Salt Lake City, UT; TEXAQS 2000, Houston, TX.

Education

University of Heidelberg, Germany Diploma in physics February 1992

University of Heidelberg, Germany Ph.D. in physics February 1996

University of California, Irvine, U.S.A. Postdoctoral Researcher in Atmospheric Chemistry

April 1996

- June 1997

Institut für Umweltphysik, University of Heidelberg, Germany

Postdoctoral Researcher in Atmospheric Chemistry

August 1997

- June 1999

Appointments

Assistant Professor, Dept. Atmospheric Sciences, UCLA July 1999

-June 2005

Associate Professor, Dept Atmospheric and Oceanic Sciences, UCLA July 2005 – present

Awards

NSF Career Award 2005

Selected Publications

Stutz, J., Wong, K.W., Lawrence, L., Ziemba, L., Flynn, J.H., Rappenglück, B., Lefer, B. Nocturnal NO3 radical chemistry in Houston, TX, Atmospheric Environment (2009), doi: 10.1016/j.atmosenv.2009.03.004

Stutz, J., H.-J. Oh, S. I. Whitlow, C. Anderson, J. E. Dibb, J. H. Flynn, B. Rappengluck, and B. Lefer (2009) Simultaneous DOAS and mist-chamber IC measurements of HONO in Houston, TX, Atmospheric Environment, doi:10.1016/j.atmosenv.2009.02.003.

Platt, U. and J. Stutz, Differential Optical Absorption Spectroscopy: Principles and Applications, Springer Verlag, Heidelberg, 597pp, 2008.

Stutz, J., O. Pikelnaya, S. C. Hurlock, S. Trick, S. Pechtl and R. von Glasow, Daytime OIO in the Gulf of Maine, Geophys. Res. Lett., 34, L22816, doi:10.1029/2007GL031332, 2007.

Brown, S. S., W. P. Dubé, H. D. Osthoff, J. Stutz, T. B. Ryerson, A. G. Wollny, C. A. Brock, C. Warneke, J. A. de Gouw, E. Atlas, J. A. Neuman, J. S. Holloway, B. M. Lerner, E. J. Williams, W. C. Kuster, P. D. Goldan, W. M. Angevine, M. Trainer, F. C. Fehsenfeld1 and A. R. Ravishankara (2007), Vertical profiles in NO3 and N2O5 measured from an aircraft: Results from the NOAA P-3 and surface platforms



during NEAQS 2004, J. Geophys. Res., 112, D22304, doi:10.1029/2007JD008883., 2007

Keene, W. C., J. Stutz, A. P. Pszenny, J. R. Maben, E. V. Fischer, A. M. Smith, R. von Glasow, S. Pechtl, B. C. Sive, and R. K. Varner, Inorganic chlorine and bromine in coastal New England air during summer, J Geophys Res, 112(D10), doi: 10.1029/2006JD007689, 2007

Pikelnaya O., Hurlock S. H., Trick S., and J. Stutz, (2007), Intercomparison of multiaxis and long-path differential optical absorption spectroscopy measurements in the marine boundary layer, J. Geophys. Res., 112, D10S01, doi:10.1029/2006JD007727.

Wang, S., R. Ackermann, J. Stutz, Vertical profiles of NOx chemistry in the polluted nocturnal boundary layer in Phoenix, AZ: I. Field observations by long-path DOAS, Atmos. Chem. Phys., 6, 2671–2693, 2006

Williams, E. J., F. C. Fehsenfeld, B. T. Jobson, W. C. Kuster, P. D. Goldan, J Stutz, and W. A. McClenny, Comparison of ultraviolet absorbance, chemiluminescence, and DOAS instruments for ambient ozone monitoring, Environ. Sci. Technol., 40, 5755-5762, 2006

Stutz, J., B. Alicke, R. Ackermann, A. Geyer, A. White, and E. Williams, Vertical profiles of NO3, N2O5, O3, and NOx in the nocturnal boundary layer: 1. Observations during the Texas Air Quality Study 2000, J. Geophys. Res., 109, doi:10.1029/2003JD004209, 2004.

Alicke, B., Hebestreit, K., Stutz, J., Platt, U., Iodine Oxide in the Marine Boundary Layer, Nature, 397, 572 - 573, 1999.

Hebestreit, K., Stutz, J., Rosen, D., Matveev, V., Peleg, M., Luria, M., Platt, U., First DOAS measurements of tropospheric BrO in mid latitudes, Science, 283, 55 - 57, 1999.

Stutz, J., Platt, U., Improving long-path differential optical absorption spectroscopy with a quartz-fiber mode mixer, Appl. Optics, 36, 1105 - 1115, 1997.

Stutz, J., Platt, U., Numerical analysis and estimation of the statistical error of differential optical absorption spectroscopy measurements with least-squares methods, Appl. Optics, 35, 6041 - 6053, 1996.

Senne, T., Stutz, J., Platt, U., Measurements of the latitudinal distribution of NO2 column density and layer height in Oct/Nov 1993, Geophys. Res. Lett., 23, 805 - 808, 1996.

Kreher, K., Fiedler, M., Gomer, T., Stutz, J., Platt, U., The latitudinal distribution (50°N-50°S) of NO2 and O3 in October/November 1990, Geophys. Res. Lett., 22, 1217 - 1220, 1995.

Hoffmann, D., Bonasoni, P., De Maziere, M., Evangelisti, F., Giovanelli, G., Goldmann, A., Goutail, F., Harder, J., Jakoubek, R., Johnston, P., Kerr, J., Matthews, W.A., McElroy, T., Mount, R.M.G., Platt, U., Pommerau, J-P., Sarkissian, A., Simon, P., Solomon, S., Stutz, J., Thomas, A.; Van Roozendael, M., Wu, E., Intercomparison of UV/visible spectrometers for measurements of stratospheric NO2 for the network for the detection of stratospheric change, J. Geophys. Res., 100, 16765 - 16791, 1995.



H. Letters of Commitment



October 9, 2009



Dear Dr. Jensen:

The Mesoscale Atmospheric Processes Branch of NASA Goddard Space Flight Center is pleased to support your proposal to NASA’s Earth Venture-1 entitled, “Airborne Tropical Tropopause Experiment.” This letter is to affirm the commitment of your Co-Investigator, Dr. Matthew McGill, and the availability of the Cloud Physics Lidar (CPL) instrument. Dr. McGill will be available to support the work as outlined in your proposal.

A central aspect of your proposal involves use of the CPL instrument, for which Dr. McGill is the Principal Investigator. I can assure you that CPL will be available to support your project during the periods identified in your proposal.

We look forward to working with you on this exciting project.

Sincerely,

Dr. David Starr

Head, Mesoscale Atmospheric Processes Branch

Laboratory for Atmopsheres

Goddard Space Flight Center



I. Current and Pending Support for PI and Co-Is

Short Title PI on Award Agency & POCPerformance Period

Total BudgetCommitment of PI or Co-I



J. Compliance with U.S. Export Laws and Regulations



K. References

Works Cited

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2. Boehm, M. T. and Verlinde, J. Stratospheric influence on upper tropospheric tropical cirrus. Geophys. Res.Lett. 2000, Vol. 27, pp. 3209–3212.

3. Holton, J. and Gettelman, A. Horizontal transport and dehydration of the stratosphere. Geophys. Res.Lett. 2001, Vol. 28, pp. 2799-2802.

4. Gettelman, A., et al. Radiation balance of the tropical tropopause layer. J. Geophys. Res. doi:1029/2003JD004 190, 2004, Vol. 109.

5. Park, M., et al. Transport above the Asian summer monsoon anticyclone inferred from Aura Microwave Limb Sounder tracers. J. Geophys. Res. doi:10.1029/2006JD008 294, 2007, Vol. 112.

6. Durran, D. R., et al. The mesoscale dynamics in thin tropical tropopause cirrus. J. Atmos. Sci. 2009, Vol. 1. In Press.

7. Haladay, T. and Stephens, G. L. Characteristics of tropical thin cirrus clouds deduced from joint CloudSat and CALIPSO measurements. J. Geophys. Res. doi:10.1029/2008JD010 675, 2009, Vol. 114.

8. Thuburn, J. and Craig, G. C. Stratospheric influence on tropopause height: The radiative constraint. J. Atmos. Sci. 2000, Vol. 57, pp. 17-28.

9. Hartmann, D. L., Holton, J. R. and Fu, Q. The heat balance of the tropical tropopause, cirrus, and stratospheric dehydration. Geophys. Res. Lett. 2001, Vol. 28, pp. 1969-1972.

10. Randel, W. J. and Wu, F. Kelvin wave variability near the equatorial tropopause observed in GPS radio occultation measurements. J. Geophys. Res. D03102, doi:10.1029/2004JD005006, 2005, Vol. 110.

11. Randel, W. J., et al. Decreases in stratospheric water vapor since 2001: Links to changes in the tropical tropopause and the Brewer-Dobson circulation. J. Geophys. Res. D12312, doi:10.1029/2005JD006744, 2006, Vol. 111.

12. Fujiwara, M., et al. Cirrus observations in the tropical tropopause layer over the western Pacific. J. Geophys. Res. doi:10.1029/2008JD011 040, 2009, Vol. 114.

13. Gettelman, A., et al. The Tropical Tropopause Layer 1960-2100. Atmos. Chem. Phys. 2009, Vol. 9, pp. 1621-1637.

14. Fueglistaler, S., et al. Stratospheric water vapor predicted from the Lagrangian temperature history of air entering the stratosphere in the tropics. J. Geophys. Res. doi:10.1029/2004JD005 516, 2005, Vol. 110.

15. Haynes, P. and Shuckburgh, E. Effective diffusivity as a diagnostic of atmospheric transport 1. Stratosphere. J. Geophys. Res. 2000, Vol. 105.

16. Fujiwara, M., et al. Turbulence at the tropopause due to breaking Kelvin waves observed by the Equatorial Atmosphere Radar. Geophys. Res.Lett. doi:10.1029/2002GL016278, 2003, Vol. 30, p. 1171.

17. Aschmann, J., et al. Modeling the transport of very short-lived substances into the tropical upper troposphere and lower stratosphere. Atmos. Chem. Phys. Discuss. 2009, Vol. 9, pp. 18511-18543.

18. Fueglistaler, S., Wernli, H. and Peter, T. Tropical troposphere-to-stratosphere transport inferred from trajectory calculations. J. Geophys. Res. 109 (D03108), 2004, Vol. doi: 10.1029/2003JD004069.

19. World Meteorological Organization, Scientific Assessment of Ozone Depletion: 2006. WMO Report. 2007, Vol. 50.

20. Salawitch, R. J., et al. Sensitivity of ozone to bromine in the lower stratosphere. Geophys. Res. Lett. 32, 2005, Vol. 32, doi:10.1029/2004GL021504.

21. Dorf, M., et al. Bromine in the tropical troposphere and stratosphere as derived from balloon-borne BrO observations. Atmos. Chem. Phys. 2008, Vol. 8, pp. 7265-7271.

22. Sinnhuber, B. M. and Folkins, I. Estimating the contribution of bromoform to stratospheric bromine and its relation to dehydration in the tropical tropopause layer. Atmos. Chem. Phys. 2006, Vol. 6, pp. 4755-4761.



23. Bucholtz, A., et al. measured heating rates of a tropical subvisible cirrus cloud. J. Geophys. Res. 2009, Vol. 1. Submitted.

24. Wang, L., et al. Small-scale gravity waves in ER-2 MMS/MTP wind and temperature measurements during CRYSTAL-FACE. Atmos. Chem. Phys. 2006, Vol. 6, pp. 1091–1104.

25. Speidel, M., et al. Sulfur dioxide measurements in the lower, middle and upper troposphere: Deployment of an aircraft-based chemical ionization mass spectrometer with permanent in-flight calibration. Atm. Environ. 2007, Vol. 41, pp. 2427-2437.

26. Fiedler, V., et al. East Asian SO2 pollution over Europe, Part1: Airborne trace gase measurements and source identification by particle dispersion model simulations. ACP. 2009, Vol. 9, pp. 4717-4728.

27. Roiger, A., et al. PAN measurements in the summertime Arctic troposphere and lowermost stratosphere using an airborne ion trap chemical ionization mass spectrometer. ACP. 2009. To be submitted.

28. Gettelman, A. and Hönninger, G. The role of halogen species in the troposphere. Chemosphere. 2003, Vol. 52, pp. 325-338.

29. Weidner, F., et al. Balloon-borne Limb profiling of UV/vis skylight radiances. Atmos. Chem. Phys. 2005, Vol. 5, pp. 1409–1422.

30. Folkins, I. and Martin, R. V. The vertical structure of tropical convection, and its impact on the budgets of water vapor and ozone. J. Atmos. Sci. 2005, Vol. 62, pp. 1560-1573.

31. Gettelman, A. and de Forster, P. M. A climatology of the tropical tropopause layer. J. Meteor. Soc. 2002, Vol. 80, pp. 911-924.

32. Gettelman, A., et al. Transport of water vapor in the tropical tropopause layer. Geophys. Res. Lett. 2002, Vol. 29, 1.

33. Randel, W. J., Wu, F. and Gaffen, D. Interannual variability of the tropical tropopause derived from radiosonde data and NCEP reanalysis. J. Geophys. Res. 2000, Vol. 105, pp. 15509-15524.

34. Comstock, J. M., Ackerman, T. P. and Mace, G. G. Ground based remote sensing of tropical cirrus clouds at Nauru Island: Cloud statistics and radiative impacts. J. Geophys. Res. doi:10.1029/2002JD002 203, 2002, Vol. 107.

35. Corti, T., et al. The impact of cirrus clouds on tropical troposphere-to-stratosphere transport. Atmos. Chem. Phys. 2006, Vol. 6, pp. 2539–2547.

36. Folkins, I. and Martin, R. V. The vertical structure of tropical convection and its impact on the budgets of water vapor and ozone. J. Atmos. Sci. 2005, Vol. 62, pp. 1560-1573.

37. Hartmann, D. L., Holton, J. R. and Fu, Q. The heat balance of the tropical tropopause, cirrus, and stratospheric dehydration. Geophys. Res.Lett. 2001, Vols. 28, 1969-1972.

38. Boehm, M. T. and Verlinde, J. Stratospheric influence on upper tropospheric tropical cirrus. Geophys. Res.Lett. 2000, Vol. 27, pp. 3209–3212.

39. Comstock, J. M., Ackerman, T. P. and Mace, G. G. Ground based remote sensing of tropical cirrus clouds at Nauru Island: Cloud statistics and radiative impacts. J. Geophys. Res. doi:10.1029/2002JD002 203, 2002, Vol. 107.

40. Corti, T., et al. The impact of cirrus clouds on tropical troposphere-to-stratosphere transport. Atmos. Chem. Phys. 2006, Vol. 6, pp. –2547.

41. Haynes, P. and Shuckburgh, E. Effective diffusivity as a diagnostic of atmospheric transport 1. Stratosphere. J. Geophys. Res. 2000, Vol. 105, pp. 22777–22794.
