simulating atmospheric co 2 for 2000: our quandary, our hypotheses and a case study
DESCRIPTION
Simulating Atmospheric CO 2 for 2000: Our Quandary, Our Hypotheses and a Case Study. Using Analyzed Climate, Transport and Satellite Vegetation. Sheri L. Conner Gausepohl TRANSCOM Meeting 13 - 16 June 2005 Paris, France. Introduction. Research Goals - PowerPoint PPT PresentationTRANSCRIPT
Simulating Atmospheric CO2
for 2000: Our Quandary, Our Hypotheses and a Case Study
Using Analyzed Climate, Transport and Satellite Vegetation
Sheri L. Conner Gausepohl
TRANSCOM Meeting13 - 16 June 2005
Paris, France
Introduction
• Research Goals
• Team: NASA/Goddard, CSU, NOAA-CMDL
Oak Ridge Lab
• Models: SiB3 and PCTM
• Experiment Overview
• Our Quandary
• Our Hypotheses
• Case Study
• Next Steps
Goals
• Create a synthetic atmospheric [CO2 ] product with realistic diurnal, synoptic and seasonal variations with quantified error
– Sub-sampling for various observing systems– Testing inverse methods
– Creating lateral boundary [CO2] conditions for mesoscale models (SiB-RAMS)
– Testing flux models and hypotheses of surface exchanges
Team
• NASA/Goddard– Randy Kawa– Steven Pawson– Jim Collatz– Zhengxin Zhu
• CSU– A. Scott Denning– Kevin Gurney– Ian Baker– John Kleist– Ravi Lokupitiya– Andrew Philpott– Lara Prihodko– Owen Leonard– Erin Chorak– Sheri Conner Gausepohl
With many thanks to CMDL and Joe Berry and Steve Montzka
• NOAA - CMDL– Arlyn Andrews– Kevin Schaefer
• Oak Ridge Lab– David Erickson III
Parameterized Chemical Transport Model (PCTM)
U U
PCTM – Previous Results
Thanks to Kevin Gurney and Scott Denning
PCTM TRANSCOM Responses
CO
2 C
on
cen
trat
ion
(p
pm
)
Simple Biosphere Model (SiB3)
Thanks to Piers Sellers, Ian Baker et al.
Experiment Overview
NDVI10
years
3 years
GEOS – 4 DASMeteorology
(core Goddard GCM)
SiB3Biosphere
PCTMTransport
(core Goddard GCM)
IGBP Soils
DeFries Biome Types
Met Fields1º x 1.25º x 55L x 3/6 hours
Met Fields1º x 1.25º x 3 hours
NEE1º x 1.25º x 1 hour
18 years
3 years
NCEP
Takahashi Ocean 1997
Andres Fossil Fuel Emissions
1990
[CO2]2º x 2.5º x 25L x 1 hour
www.noaa.gov
www.e-design.org.uk
www.nws.noaa.gov/rrs/overview.htm
www.noaa.gov
http://www.fas.harvard.edu/~cobra/http://public.ornl.gov/ameriflux/
faculty.law.lsu.edu/ccorcos/biblio/flask.gif
Quandary: Early Drawdown
Hypotheses• Autotrophic Respiration
• Photosynthesis: Normalized Difference Vegetation Index (NDVI)
• Radiation
Case Study: COS• Use carbonyl sulfide (COS)
to quantify error in
photosynthesis
Data: red Model: green
Hypothesis: Respiration
• Heterotrophic Respiration– 50% of annual Net Assimilation (GPP - Respiration leaf maintenance)
– Seasonality defined from Soil Temperature & Soil Moisture
• Autotrophic Respiration– 50% of annual Net Assimilation– Seasonality defined by FPAR (canopy nitrogen)
New Respiration Calculation:
Thanks to Kevin Schaefer
Temperate North America
Old Scheme: red New Scheme blue CASA: green T3L3: black
-60.00
-55.00
-50.00
-45.00
-40.00
-35.00
-30.00
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
5.00
10.00
15.00
20.00
25.00
30.00
1 2 3 4 5 6 7 8 9 10 11 12
Month
Brief Note re: SiB3, CASA
SiB3
• FPAR estimated from mid-month linearly interpolated NDVI, BUT solar zenith angle dependent FPAR
• Single respiring carbon pool generates respiration that varies with soil temperature, soil moisture
CASA
• FPAR estimated from mid-month linearly interpolated NDVI , BUT nadir FPAR
• Multiple respiring carbon pools generate respiration that varies with amount of material in labile pools, air temperature, soil moisture
Hypothesis: NDVINew NDVI Interpolation Schemes:
NDVI at WLEF, Wisconsin
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1 31 61 91 121 151 181 211 241 271 301 331 361
Day of Year (1996)
Normalized Difference Vegetation Index (NDVI)
NDVI at Kenai, Alaska
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1 31 61 91 121 151 181 211 241 271 301 331 361
Day of Year (1996)
Normalized Difference Vegetation Index (NDVI)
Thanks to Andrew Philpott and the Tucker Group (NASA - Goddard)
Data: green Old Scheme: Blue New Scheme: Red
• Assign maximum value composite NDVI values to:- day observed OR
- first day, mid-point, last day of month based on curvature
and linearly interpolate
• Tropics are an issue due to cloud contamination
Hypothesis: Radiation
• Separate treatment of sunlit and shaded leaves – Photosynthesis– Stomatal conductance– Leaf temperature– Transpiration
• Solar zenith angle dependence of canopy shading acts to delay onset of photosynthesis in new scheme
Improved Canopy Radiation Scheme:
Case Study: Assessing Photosynthesis vs. Respiration
• Primary source: oxidation of marine organic matter
• Primary sink: terrestrial biosphere
• Large seasonal variation strongly related to CO2
– Sink process identical to CO2 in photosynthesizing plants
– No source process akin to respiration from biosphere
COS: the Sulfur Analog of CO2
Thanks to CMDL for CO2 data and to Steve Montzka for COS data
[COS]
355.00
375.00
395.00
415.00
435.00
455.00
475.00
495.00
515.00
535.00
1 3 5 7 9 11 13 15 17 19 21 23
Month (2000 - 2001)
ppt[COS] WLEF
[COS] NWR
[CO2]
355.00
360.00
365.00
370.00
375.00
380.00
385.00
1 3 5 7 9 11 13 15 17 19 21 23
Month (2000 - 2001)
ppm
[CO2] WLEF
[CO2] NWR
Case Study: Assessing Photosynthesis vs. Respiration
• Estimate timescale of mixing between mixed layer and free troposphere from water vapor and CO2 gradients
• Calculate COS drawdown using timescale and SiB3
• Compare COS drawdown to observations of COS at WLEF
COS: The PlanFree Troposphere
Mixed Layer
Canopy Air Space
NOTE: SiB3 currently calculates all but one necessary resistance
Next Steps
1. Diagnose why SiB3-PCTM has springtime bias using
COS (carbonyl sulfide)
2. (Improve SiB3 per results of diagnosis)
3. Run SiB3 with new schemes
4. Run PCTM at 1.0º x 1.25º resolution with updated
fossil fuel and ocean fluxes
5. Calculate errors on [CO2] using observations
6. Release hourly global [CO2] product to science
community with quantified errors
Thank you very much for your kind attention.