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Managed by UT-Battelle for the Department of Energy Estimating the North American Carbon Balance Using Inter- Comparison Among Inversions, Regional Terrestrial Biogeochemistry Models, and Observational Data Wilfred Post, Deborah Huntzinger, Kenneth Davis, Brett Raczka, Daniel Hayes, Anna Michalak, Yaxing Wei, Andrew Jacobson, Robert Cook, and North American Carbon Program Regional- Interim Synthesis Participants
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2Managed by UT-Battelle for the Department of Energy Presentation_name North America Carbon Program Synthesis Objectives Utilize new and emerging NACP research findings to develop a picture of the current state of the North America carbon cycle Identify continental scale carbon sources/sinks Characterize continental scale inter-annual variation Assess our capability of modeling and measuring large scale carbon cycle dynamics
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3Managed by UT-Battelle for the Department of Energy Presentation_name
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4Managed by UT-Battelle for the Department of Energy Data sets assembled and regridded for comparison with models MODIS monthly GPP, annual NPP Soil C from surveys Inventory based C pool and flux estimates –Forest biomass from inventory –Crop NPP from crop yield data Comparison with eddy flux – crossover model runs with Site Synthesis Presentation_name
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5Managed by UT-Battelle for the Department of Energy Participating Models 19 TBMs Models differ in: – Prognostic versus diagnostic – Driver data – Vegetation and soil properties – Photosynthetic formulation – # of carbon pools, soil carbon decomposition dynamics – Processes included, etc. 25 Inverse Models – 20 models with TRANSCOM results – 8 models with post-TRANSCOM results resolved to 1x1 degree Presentation_name
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6Managed by UT-Battelle for the Department of Energy TBM Model Net Flux for North America Across model mean net flux; 2000-2005 NEP = 0.66 PgC/yr (1.8 to -0.25 PgC/yr) NPP = 9.2 PgC/yr (6.2 to 13.8 Pg C/yr) GPP = 18.4 PgC/yr (9.9 to 31.7 Pg C/yr) Rh = 8.6 PgC/yr (5.8 to 13.1 Pg C/yr) Presentation_name
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7Managed by UT-Battelle for the Department of Energy Long-term Mean Summer (June, July, August) Net Ecosystem Productivity Presentation_name
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8Managed by UT-Battelle for the Department of Energy Can we diagnose the reasons for the lack of consensus in TBM performance? Driver data Photosynthesis formulation Phenology Decomposition – N limitation Regional differences Missing important processes Presentation_name
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9Managed by UT-Battelle for the Department of Energy Crossover Models - Regional model runs are more positively biased for GPP. Site model runs closer to observations. Raczka et al. (in preparation)
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10Managed by UT-Battelle for the Department of Energy Long-Term Mean NEE – TBMs and Inversions Presentation_name
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11Managed by UT-Battelle for the Department of Energy Presentation_name
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12Managed by UT-Battelle for the Department of Energy Net NPP over U.S. Agricultural Lands: Models Compared to NASS Inventory-Based Data Presentation_name
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13Managed by UT-Battelle for the Department of Energy Net NPP Spatial Pattern Over U.S. Agricultural Lands: Models Compared to NASS Inventory-Based Data Presentation_name
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14Managed by UT-Battelle for the Department of Energy Inventory – Model Comparison Presentation_name Data SourcesYears of DataLocation Fluxes and Pools Available Source Canada Mgd. Forest (CBM-CFS3) 2000 – 2006Canada (n = 15) NEE, NPP, VegC, Fire Emissions Kurz et al. Stinson et al. Canada Croplands 2000 – 2006 (average) Canada (n = 8)NEE, NPPMcConkey U.S. Forest (FIA / CCT)2000 – 2006 Continental U.S. plus Alaska (n = 49) NEE, VegCSmith & Heath U.S. Croplands2000 – 2005 Continental U.S. (n = 49) NEE, NPPWest et al. Mexico2000 - 2005Mexico (n = 32) NEE, VegC, Fire Emissions deJong et al. 2010
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15Managed by UT-Battelle for the Department of Energy Accounting for Lateral Fluxes Presentation_name CO 2 Residu e VEGC SOIL C Harve st Livestoc kC CH 4 HumanC CH 4 Consumption Imports – Exports Land Use Change PROD C FireRH NPP Fire NEE Grasslands / Settlements CO 2 Uptake CO 2 Release NEE Forest / Cropland Sector “Other” Lands Sector Export
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16Managed by UT-Battelle for the Department of Energy INVENTORY DATA TOTALFORESTLANDCROPLANDOTHER LANDS FORWARD MODELS INVERSE MODELS Mean average annual NEE (Tg C yr -1 ), 2000 to 2006
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17Managed by UT-Battelle for the Department of Energy Summary Regional TBM comparisons indicate a lack of consensus for NEP and component fluxes – GPP, Ra, Rh Analyses to diagnose the causes reveal: – Model formulation plays a significant role. – Different weather driver data sets greatly impact GPP TBM Re tends to be tightly related to GPP – this dampens the NEE seasonal cycle and IAV Annual NEE cycle amplitude is small for TBM compared to inversions. Presentation_name
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18Managed by UT-Battelle for the Department of Energy Conclusions Regional C modeling enterprise needs a more rigorous approach to development and evaluation. Large disparities remain in estimates based on temporal and spatial extrapolations of experimental and site based understanding. Additional data, especially based on spatially extensive measurements, needs to be integrated into the modeling system approach. –Improve model algorithms/parameters –Improved diagnostic and predictive usefulness –Evaluate model skill –Develop useful benchmarks An transition from data-poor to data-rich approach is emerging for developing multi-stream observing systems and modeling system analyses. The NACP regional synthesis has contributed by exploring how a wider range of data sources can be used. Presentation_name
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19Managed by UT-Battelle for the Department of Energy Next Steps RECCAP –If you have model results for 1990-2008 we would be interested in incorporating them into the North American RECCAP chapter. –Contact Mac Post MsTMIP –If you didn’t make it to the Side Meeting yesterday you are still invited to participate –Contact Deborah Huntzinger –Check the NACP web site for a MsTMIP e-mail list to be started soon. Presentation_name
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20Managed by UT-Battelle for the Department of Energy Acknowledgments NASA Terrestrial Ecology support the Modeling and Synthesis Thematic Data Center (MAST-DC) DOE Office of Science for workshop support NOAA support for collecting inversion model results Generous contributions of time and resources from any modeling teams and data providers that made these analyses possible Presentation_name
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