overall goal : strengthen arctas’s ability to achieve the goals of its

P. Russell, POLARCAT 1st Int’l Sci Planning Mtg

Paris, France 4-6 Jun 2007

Scientific Coordination Services for Aerosol-Cloud-Radiation Goals in ARCTAS

Phil Russell, NASA Ames

Overall Goal: Strengthen ARCTAS’s ability to achieve the goals of its

- Theme 3: Aerosol Radiative Forcing (including indirect aerosol forcing via clouds)

- Theme 2: Boreal Forest Fires

Also contribute to ARCTAS’s: -Theme 1, Long-Range Transport of Pollution to the Arctic,

-Theme 4, Chemical Processes.



Scientific Coordination Services for Aerosol-Cloud-Radiation Goals in ARCTAS

We expect that this work will also contribute to achieving the following POLARCAT objectives:

• Determine the vertical layering of Arctic pollution and the optical properties of Arctic aerosol particles.

• Characterize the direct radiative effects within pollution layers in the Arctic.

• Investigate interactions of aerosols with clouds and their impact on radiative forcing.

• Quantify albedo changes of snow and ice surfaces and resulting radiative effects due to deposition of black carbon from anthropogenic and biomass burning sources.

• Study impact of boreal forest fire emissions on the composition of the troposphere and on soot deposition.

• Determine the fate and effects of material injected by pyro-convection.

• Validate aerosol, trace gas, and cloud products of space observations from polar orbital satellites.



ARCTAS strategy for enabling exploitation of NASA satellite data to improve

understanding of arctic atmospheric composition and climate*

*Source: ARCTAS White Paper

**

**

**

**+ clouds & radiation



King Air

P-3

King Air

P-3



Expected Flight Patterns for Aerosol-Cloud-Radiation Goals in ARCTAS

King Air

P-3



The NASA P-3

Expected Payload for P-3 in ARCTAS*Ames

AirborneTracking

Sun-photometer

(AATS)

Solar Spectral Flux Radiometer (SSFR)

Cloud Absorption Radiometer (CAR)

Other Possibilities: Remote/Radiation- Research Scanning Polarimeter (RSP)- Broadband flux radiometers- Rainbow, NIR, TIR cloud/aer cameras In situ- Aerosol scat., abs., ext., size, humidification, chemistry, …

Position & Orientation System (POS)

Met Sensors & Nav/Met Data System

*Depends on proposals, selection, funding

AATS-14AATS-14

CARCAR

RSPRSP

SSFR

NavMetNavMet

POSPOS

J31 in INTEX-B/MILAGRO: Instrument Locations

AATS-14Ames

AirborneTracking Sunphotometer

SSFR - Solar Spectral Flux

Radiometer NASA AATS-14 in ARCTAS

Redemann, Russell, Livingston et al.

(1) Brief summary of scientific objective(s) Horizontal and vertical structure of Arctic Haze and high-lat. biomass

burning aerosol Properties of Arctic aerosol in the vicinity of clouds Direct radiative effects of Arctic Haze and high-lat. biomass burning

aerosol from flux and AOD gradient method, dependence of radiative forcing on surface albedo

Spectral single scattering albedo of Arctic Haze and high-lat. biomass burning aerosol

Validation of satellite retrievals of Arctic aerosol properties

POLARCAT/ARCTAS Science Objectives

Solar Spectral Irradiance

Objectives/Measurements1. Surface spectral albedo, area-averaged and along flight track2. Characterize surface radiation budget in Arctic and quantify aerosol

perturbations. Aerosol forcing, absorption, and single scattering albedo.3. Retrievals of cloud droplet radius and optical depth; aerosol indirect effect4. Test/validation/comparison with satellite cloud retrievals (MODIS), aerosol

effects on remote sensing of clouds.

Solar Spectral Flux Radiometer (SSFR): Up- and downward irradiance 380 nm to 2100 nm 8-12 nm spectral resolution 1 Hz sampling 3-5% absolute accuracy; 0.5% precision Experience operating in the ARCTAS environment:

FIRE SHEBA and MPACE



AIRBORNE BRDF AND

AEROSOL MEASUREMENTS

FOR THE ARCTAS CAMPAIGN

Charles K. Gatebe1,2 and Michael D. King2

1University of Maryland, Baltimore County2NASA Goddard Space Flight Center



CAR Science Goals in ARCTAS:

Measure spectral directional reflectance overArctic sea ice (snow covered, melt-season &tundra) and clouds.

• Derive surface BRDF and column aerosoloptical properties of different atmosphericlayers from combined data sets: CAR, AATSand/or AERONET over the Arctic sea ice andclouds.

• Compare with in situ measurements ofaerosol optical properties and validatesatellite retrievals.



Bidirectional Reflectance Measurements:

Previous Experiments

Locations and Experiments❑ Snow-covered sea ice and tundra– Lead Experiment (LEADEX), April 1992

❑ Melt-season sea ice and snow-free tundra– Arctic Radiation Measurements in Column Atmosphere-surface System (ARMCAS), June 1995– First ISCCP Radiation Experiment-Arctic Cloud Experiment (FIRE-ACE), May-June 1998

❑ Arctic stratus clouds– FIRE-ACE, May-June 1998

ARCTAS Webcon, 12 April 2007

NASA King Air B200 Deployment Plans for ARCTAS

NASA LaRC

Chris HostetlerJohn Hair

Richard FerrareAnthony CookDavid HarperMichael PittsYongxiang HuDavid Flittner

Columbia Univ/NASA/GISS Brian Cairns

University of Maryland Baltimore County

Vanderlei MartinsJuying Warner

Platform/Location

• Fairbanks, Alaska?; Deadhorse, Alaska? (~330 km ESE of Barrow)• Help support DOE ARM ISDAC mission

• Cold Lake, Alberta • Near center of historical fire region

July

Platform – NASA Langley King Air B-200– 27-28 kft nominal flight altitude– ~60 science flight hours each for

spring and summer deployments

April July

(b) Extinction; AOT (532 nm)

0.0

0.1

0.2

0.3

0.4

AO

T (

53

2 n

m)

Extinction; AOT (532 nm)

West side of MC basin– High extinction/backscatter ratio, low depolarization: urban

pollution

East side of MC basin– Low extinction/backscatter ratio, high depolarization: dust

Extinction/Backscatter Ratio

Depolarization

Determination of Aerosol Type

Aerosol types inferred from HSRL measurementsOver Mexico City (MC) during INTEX-B/MILAGRO

Science Objectives

Map vertical and horizontal distribution of aerosols– Use profiles of extinction, backscatter, and depolarization to characterize

the vertical distribution of aerosol optical properties and type– Determine relative contribution of various aerosol types to aerosol

extinction and optical depth (e.g. pollution, smoke from boreal fires, etc.)– Determine vertical location of aerosols in relation to clouds and PBL – Assess aerosol model transport predictions – Provide vertical context for in situ and remote sensing measurements on

the DC-8, J-31 and/or P-3– Compare aerosol extinction and optical depth measurements with

satellite, airborne, and/or ground based sensors Assess satellite (MODIS, MISR) retrievals of aerosol optical depth Validate CALIOP lidar on the CALIPSO satellite Investigate active–passive retrieval techniques of aerosol optical and

microphysical properties– HSRL + MODIS CALIPSO + MODIS– HSRL + RSP CALIPSO + POLDER– HSRL + LAABS + RSP/HySPAR future satellite mission concept

Investigate new remote sensing methods for retrieving cloud drop size Investigate combined use of lidar and hyperspectral imager for

understanding marine productivity

Planned Instruments

Hosteter, Hair, et al. (LaRC) Independently measures

aerosol/cloud extinction and backscatter at 532 nm

Includes – Backscatter channels at 1064

nm– Polarization sensitivity at 532

and 1064 nm Measurement capabilities

– Extensive measurements• Backscatter at 532 and 1064 nm• Extinction at 532 nm

– Intensive measurements• Color ratio (or Angstrom coeff.)

for backscatter (β1064/ β532)• Extinction-to-backscatter ratio at

532 nm • Depolarization at 532 and 1064

nm

Cairns (Columbia/NASA/GISS) Measures total and linearly

polarized reflectance in 9 spectral bands (412 – 2.25 m)

Retrieval of Stokes parameters Aerosol retrievals

Optical depth Size distribution Refractive index

Cloud retrievals Optical depth Effective radius, variance of

cloud droplet size distribution Cloud top and base heights Liquid water path and droplet

number distribution

High Spectral Resolution Lidar (HSRL) Research Scanning Polarimeter (RSP)

Digital Camera (LaRC)•provide frequent (1-2 sec) images for providing context of the HSRL measurements relative to clouds

Possible Instruments

• Flittner, Hu (LaRC)• Full stokes vector (including

circular polarization)• Continuous spectral coverage

from 412 to 865 nm at 20 nm spectral resolution

• Multi-angle viewing geometry: +/- 60º along flight vector

• Measurements to investigate combined active-passive aerosol retrievals

• Pitts (LaRC)• Spectrum of upwelling radiances

in the oxygen A-band (760-770 nm)

• 0.03 nm spectral resolution• Measurements to investigate:

• combined active-passive aerosol retrievals

• Photon path length statistics (clear and cloudy)

HyperSpectral Polarimeter for Aerosol Retrievals (HySPAR)

Langley Airborne A-band Spectrometer (LAABS)

• Martins (UMBC/NASA/GSFC)• Single wavelength camera

measures 6 polarization angles to observe diffraction pattern of cloud rainbow

• Retrievals of cloud drop effective radius, variance

Rainbow Camera

Hyperspectral Imaging System

• Warner (UMBC)• 512 spectral bands

between 300-1050 nm• CCD • Measurements for ocean

color



P-3 flights will be coordinated with:

Satellite overflights: A-Train and other satellites (including Aura, Aqua, CALIPSO, CloudSat, PARASOL, and Terra),

Other aircraft: ARCTAS DC-8 and B-200, & possibly aircraft from other agencies (e.g., NOAA P-3, DOE G-1),

Measurements from ground sites:-Measurements of snow and ice albedo as affected by simultaneously measured soot (Warren, Clarke, Grenfell)- Radiometric and lidar measurements by AERONET, MPLNET, and other providers, including the DOE North Slope of Alaska site and the University of Alaska.

Extremely laminar transport•Sloping thin layers•Strong gradients vertically & horizontally•Frequently decoupled surface layer

(relevance of surface statistics?)•Highest concentrations may be aloft•Diamond dust and stratus near surface

40 kmVertical Structure of Arctic Haze

Chuck Brock, NOAA ESRLNASA-GISS 2007

Lidar image in April 1986:

Treffeisen et al.SAGE II observations suggest maximum vertical extent in March-April.

NEED DELIBERATE AND COORDINATED STRATEGY for linking in-situ profile data to plume and column properties

J31 flight patterns:Coordinated satellite, in-situ and radiative missions

Low altitude horizontal transect at time of satellite overpass for sat

sensor validation

OMI/Aura POLDER/Parasol MODIS/Aqua MISR, MODIS/Terra

DC-8 C-130

B200

J-31

HSRL (532 nm)AATS (519 nm)Hi GEAR (550 nm)

Aerosol extinction comparison from coordinated Aerosol extinction comparison from coordinated flights by J31 (AATS), Be200 (HSRL), & C130 (in situ)flights by J31 (AATS), Be200 (HSRL), & C130 (in situ)

[Hair, Hostettler, Ferrare, Redemann, Livingston, Clarke, et al.][Hair et al.]

Backup slides follow

Science Objectives:

Support ARCTAS and/or POLARCAT activities by providing MPLNET data and analysis from our arctic sites Barrow, BNZ (Fairbanks), Horsund (Svalbard), Thule, Eureka (2), Resolute Bay, Sodankyla (Finland), and sub arctic sites in Russia and Estonia.

An additional Arctic AERONET site at the new Tiski station in Siberia has been proposed. Funding from NASA HQ is required for this instrument (above baseline AERONET budget), and has been “promised” from HQ. If the site is online in time for this effort, we will also provide data from Tiski.

I’ll consider modest field AERONET support of these activities.

Anchorage (spring)Fairbanks (spring)Keflavik (spring)Grand ForksKiruna (spring)Edmonton (summer)Thule (spring)

POTENTIAL ARCTAS BASES AND NOMINAL DC-8 RANGESPOTENTIAL ARCTAS BASES AND NOMINAL DC-8 RANGES

0 E45 E90 E135 E180 E225 E270 E315 E

50 N

50 N

60 N

60 N

70 N

70 N

80 N

80 N

Range rings signify 4 hours out and back with full profiling for the DC-8. These range circles also reasonably describe the reach of the P-3 over 8 hours (based on the TRACE-P transit from Hawaii to Wake Island).

1. Surface spectral albedo, area-averaged and along flight track

500 1000 1500 20000.0

0.1

0.2

0.3

0.4

cos(SZA)0.7930.8470.915

ASL [m]35005003810

Surface

SSFR T0, 6-Mar-2006 T0, 15-Mar-2006 T2, 15-Mar-2006

Alb

ed

o

Wavelength [nm]

Example of SSFR measured albedo and retrieved surface albedo for MILAGRO: T0 (2 SZA), T2 (1 SZA)For the conversion SSFR albedo surface albedo, we need AOT between the surface and the aircraft.Collaboration: HSRL (extinction profiles), AERONET (AOT, SSA?, g?), aerosol in situ measurements? With HSRL measurements, can resolve surface albedo along flight track. Uncertainty (3-5%) gets larger if aerosol (AOT, SSA, g) is not sufficiently constrained.Comparison with MODIS albedo product under way. MISR?Separation of cloud features from underlying surface.

2. Radiation budget; aerosol forcing, absorption In conjunction with AATS-14 measurements, we have measured aerosol forcing, aerosol forcing efficiency, and aerosol absorption over land and over sea, for moderate surface albedo. We are hoping to do the same over ice surfaces and the open sea using: low level horizontal leg under aerosol gradient vertical profile (e.g., spiral) parallel low-level and high-level leg Currently working on aerosol + 3D cloud effects

-97.0 -96.8 -96.6 -96.4 -96.20

5

10

15

20

25 350-700 nm 864 nm

Ae

roso

l Fo

rcin

g E

ffic

ien

cy [

%]

Longitude [deg]

cloud

broadband

spectral

Example from MILAGRO: Resolve aerosol forcing along flight track

If we had had only the low-level leg, we would have had ONE average value ONLY

spiral 1

spiral 2

3. Retrieval of cloud thermodynamic phase, optical depth and effective radius

Example from ICARTT 2004

From flight legs above cloud layer, retrieve cloud water phase, optical depth and effective radiusFrom flight legs below cloud layer, water phase and optical depth.Potential for identifying/quantifying mixed phase clouds

SSFRMIDASFSSP

4. Test/validation/comparison with satellite cloud retrievals

Compare SSFR cloud retrievals with MODIS retrievalsExamine effects of aerosol layers and surface albedo on MODIS cloud retrievals.

Aerosol scattering ratio (aerosol/molecular backscatter) (532, 1064 nm)

(Δx ~ 1 km, Δz ~ 60 m) Aerosol backscatter coefficient at 532, 1064 nm (Δx ~ 1 km, Δz ~ 60

m) Aerosol extinction coefficient at 532 nm (Δx ~ 6 km, Δz ~ 300 m) Aerosol wavelength dependence (532/1064) (i.e. Angstrom exponent

for aerosol backscatter) (similar to backscatter color ratio) Total depolarization (532, 1064 nm) (Δx ~ 1 km, Δz ~ 60 m) Aerosol extinction/backscatter ratio (“lidar ratio”) (532 nm) (Δx ~ 6

km, Δz ~ 300 m) Aerosol depolarization (532, 1064 nm) (Δx ~ 1 km, Δz ~ 60 m)

Real-time display of aerosol backscatter, depolarization to help guide other aircraft

HSRL Data Products

Extensive – depend on aerosol amount and typeIntensive – depend on aerosol type

Desired External Data Temperature profile RH, f(RH) Aerosol size distribution

(under ambient RH, if possible)

Absorption/scattering coefficients

Aerosol composition Aerosol refractive index Satellite measurements

overall goal : strengthen arctas’s ability to achieve the goals of its

Documents