Model Intercomparisons and Validation: Terrestrial Carbon, an Arctic Emphasis

1. Model Intercomparisons and Validation: Terrestrial Carbon, an Arctic Emphasis Andrew Slater

3. Carbon Model Intercomparisons • EDMI – offline • C4MIP – C-Model and parent Atmosphere • C-LAMP – C-Model and CAM (CCSM Atmo) • IPCC AR5 – The next big thing …..

4. Ecosystem Dynamics Model Intercomp.

5. C4MIP – Carbon Cycle & Climate Change • 11 Models (International effort) • Coupled Atmo-Ocean-Land + Carbon GCMs • Numerous carbon pools in models • Generally fixed Q10 values (global) • No nitrogen cycle included • Simulations with & without interactive CO2 • Later found that Nitrogen limitation would decrease carbon uptake

6. C4MIP - Results • No consensus on total NPP response to Climate Change • ↑T + ↑CO2→ ? • Will the land be a sink or source? • Carbon uptake ability decreases • ↑T →↓CO2 uptake

7. Carbon-Land Model Intercomparison Project • Couple 3 models to the CCSM atmosphere • CLM3-CASA’ • CLM3-CN • LSX-IBIS • Multi-criteria objective function • Aids model development & selection

8. Carbon-Land Model Intercomparison Project

9. C-LAMP Experiments • 1000yr Spin-up + 200yr Control • Experiment 1: Offline (Reanalysis driven) • 1.1 Spin up run • 1.2 Control run (1798–2004) • 1.3 Climate varying run (1948–2004) • 1.4 Climate, CO2, and N deposition varying run (1798–2004) • 1.5 Climate, CO2, N deposition varying run with land use change (1798–2004) • Experiment 2: Coupled to CAM3 • 2.1 Spin up run • 2.2 Control run (1800–2004) • 2.3 Climate varying run (1800–2004) • 2.4 Climate, CO2, and N deposition varying run (1800–2004) • 2.5 Climate, CO2, and N deposition varying run with land use change (1800–2004)

10. IPCC AR5 and Carbon • Concentration driven (a la AR4) • No carbon feedback • Emissions driven • Full carbon coupling • Radiation code does not see CO2 • Dynamic Vegetation coupling • Land Use & Land Cover Change

11. Carbon Data – What, Where & When • Storage • Soil Carbon • Biomass Fixing • Flux Data: • FluxNet • Individual Investigators • CO2 & CH4

12. Soil Carbon – Importance of Arctic Batjes, 1996

13. Permafrost Organic Carbon Content New estimates of carbon in frozen soils (NH) Tarnocai et al 2009, GBC

14. Carbon (& other) Data Issues: • All the usual problems • Metadata • Continuity & Completeness • Quality Control • Different formats • Numerous data centers • Access • Pro’s & Con’s of different data sets • Errors: Representativeness & Instrumental

15. FluxNET

16. IPY AON Projects: Full annual cycle?

17. AON Towers: A tough environment! Imnaviat Cherskii Photos: EEuskirchen@UAF

18. Arctic Specific Matters 1950 • Highest Q10 values are in the Arctic • Rapid change • Shrub encroachment already seen • Huge carbon stocks 2002

19. 2008 2007 2006 2005 Current Carbon Emissions Trajectory of Global Fossil Fuel Emissions (Avgs.) 2000 1995 2005 2010 1990 Raupach et al 2007, PNAS; Global Carbon Project 2009

20. THANKS

21. Gridcell Landunit Glacier Wetland Vegetated Lake Urban Columns Soil Type 1 PFTs Community Land Model subgrid tiling structure Resolution For IPCC AR5 2o and 0.5o working towards 0.1o

22. Gridcell Landunit Glacier Wetland Vegetated Lake Urban Columns Soil Type 1 PFTs Vegetation change (prescribed or prognostic)

23. Mean Annual Temperature (2CO2) One Grid Cell In Canada Additional Temperature Change With Vegetation Bonan et al. (2003) Global Change Biology 9:1543-1566 Bonan & Levis, unpublished Dynamic global vegetation model (DGVM)

24. Nitrogen cycle Internal (fast) External (slow) denitrification N deposition assimilation Soil Mineral N N fixation mineralization N leaching Carbon and Nitrogen cycling (CLM-CN) Carbon cycle Atm CO2 photosynthesis Plant respiration litterfall & mortality Litter / CWD 3 C and 3 N litter pools decomposition Soil Organic Matter 3 C and 3 N soil pools Based on Biome-BGC, Thornton et al., 2009