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Simulating Atmospheric CO 2 for 2000: Our Quandary, Our Hypotheses and a Case Study

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

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Simulating Atmospheric CO 2 for 2000: Our Quandary, Our Hypotheses and a Case Study

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  1. 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 Meeting 13 - 16 June 2005 Paris, France

  2. 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

  3. 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

  4. 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 Team • NOAA - CMDL • Arlyn Andrews • Kevin Schaefer • Oak Ridge Lab • David Erickson III With many thanks to CMDL and Joe Berry and Steve Montzka

  5. U U Parameterized Chemical Transport Model (PCTM)

  6. PCTM – Previous Results Thanks to Kevin Gurney and Scott Denning PCTM TRANSCOM Responses CO2 Concentration (ppm)

  7. Simple Biosphere Model (SiB3) Thanks to Piers Sellers, Ian Baker et al.

  8. Experiment Overview GEOS – 4 DAS Meteorology (core Goddard GCM) www.e-design.org.uk Met Fields 1º x 1.25º x 3 hours NDVI SiB3 Biosphere www.noaa.gov www.nws.noaa.gov/rrs/overview.htm www.noaa.gov Met Fields 1º x 1.25º x 55L x 3/6 hours 10 years 18 years NCEP IGBP Soils NEE 1º x 1.25º x 1 hour Takahashi Ocean 1997 PCTM Transport (core Goddard GCM) 3 years DeFries Biome Types Andres Fossil Fuel Emissions 1990 3 years [CO2] 2º x 2.5º x 25L x 1 hour faculty.law.lsu.edu/ccorcos/biblio/flask.gif http://public.ornl.gov/ameriflux/ http://www.fas.harvard.edu/~cobra/

  9. 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: redModel: green

  10. Hypothesis: Respiration New Respiration Calculation: Thanks to Kevin Schaefer • 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) Temperate North America Old Scheme: redNew Scheme blue CASA: green T3L3: black

  11. 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

  12. Hypothesis: NDVI New NDVI Interpolation Schemes: • 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 Thanks to Andrew Philpott and the Tucker Group (NASA - Goddard) Data: green Old Scheme: BlueNew Scheme: Red

  13. Hypothesis: Radiation Improved Canopy Radiation Scheme: • 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

  14. Case Study: Assessing Photosynthesis vs. Respiration COS: the Sulfur Analog of CO2 • 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 Thanks to CMDL for CO2 data and to Steve Montzka for COS data

  15. Case Study: Assessing Photosynthesis vs. Respiration COS: The Plan Free Troposphere • 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 Mixed Layer Canopy Air Space NOTE: SiB3 currently calculates all but one necessary resistance

  16. Next Steps • Diagnose why SiB3-PCTM has springtime bias using COS (carbonyl sulfide) • (Improve SiB3 per results of diagnosis) • Run SiB3 with new schemes • Run PCTM at 1.0º x 1.25º resolution with updated fossil fuel and ocean fluxes • Calculate errors on [CO2] using observations • Release hourly global [CO2] product to science community with quantified errors

  17. Thank you very much for your kind attention.

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