1. Managed by UT-Battelle for the Department of Energy North American Carbon Balance – Results from the Regional Synthesis Project of the North America Carbon Program 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

2. 2Managed by UT-Battelle for the Department of Energy Presentation_name North America Carbon Program Synthesis Objectives Identification of Sources/Sinks (regional) – What are the magnitudes and spatial distribution of carbon sources and sinks, and their uncertainties during 2000-2005? Characterize Interannual Variation (regional) – What is the spatial pattern and magnitude of interannual variation in carbon fluxes during 2000- 2005? – What are the components of carbon fluxes and pools that contribute to this variation? – Do model results and observations show consistent spatial patterns in response to interannual climate variation? At intensively studied sites (flux towers) – Are the various observations and modeling estimates of carbon fluxes at individual sites consistent with each other - and if not, why?

3. 3Managed by UT-Battelle for the Department of Energy Presentation_name

4. 4Managed 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

5. 5Managed by UT-Battelle for the Department of Energy Long-term Mean Summer (June, July, August) Net Ecosystem Productivity Presentation_name

6. 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

7. 7Managed by UT-Battelle for the Department of Energy Long-Term Mean NEE – TBMs and Inversions Presentation_name

8. 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

9. 9Managed by UT-Battelle for the Department of Energy Presentation_name

10. 10Managed by UT-Battelle for the Department of Energy Net NPP over U.S. Agricultural Lands: Models Compared to NASS Inventory-Based Data Presentation_name

11. 11Managed by UT-Battelle for the Department of Energy Net NPP Satial Pattern Over U.S. Agricultural Lands: Models Compared to NASS Inventory-Based Data Presentation_name

12. 12Managed 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, FE 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, FiredeJong et al. 2010

13. 13Managed 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

14. 14Managed 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

15. 15Managed 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

16. 16Managed 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 from developing integrated observing systems and model analyses.  The NACP regional synthesis has contributed by exploring how a wider range of data sources can be used. Presentation_name

17. 17Managed 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