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The Tundra Carbon Balance - some recent results with LPJ-GUESS contributions

The Tundra Carbon Balance - some recent results with LPJ-GUESS contributions. Paul Miller Ben Smith, Martin Sykes, Torben Christensen, Arnaud Heroult, Almut Arneth, Rita Wania, Dave McGuire. Background & Outline. Why study the tundra? Relevant LPJ-GUESS developments

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The Tundra Carbon Balance - some recent results with LPJ-GUESS contributions

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  1. The Tundra Carbon Balance- some recent results withLPJ-GUESS contributions Paul Miller Ben Smith, Martin Sykes, Torben Christensen, Arnaud Heroult, Almut Arneth, Rita Wania, Dave McGuire

  2. Background & Outline • Why study the tundra? • Relevant LPJ-GUESS developments • Results from RECCAP (the present C balance) • Results from CARBO-North (the present and future C balance) Funding and Support from: • CARBO-North (EU-FP6) funded • Mistra-SWECIA • LUCCI • MERGE

  3. Tundra Tundra Boreal Forest Callaghan et al., Ambio, 2002

  4. Why Study the Tundra? Substantial future climate warming is expected, with consequences for: • Species diversity (which is less than temperate biomes - ACIA) • Vegetation (growing season length, productivity etc.) • Permafrost • Soil carbon

  5. Ongoing Warming And Amplification Linear temperature trend, 1960-2009 Paleoclimatic Evidence for Arctic Amplification Serreze & Barry, 2011

  6. More Productive Tundra Vegetation? Bhatt et al, 2010, Serreze & Barry, 2011

  7. Carbon in NH Permafrost 1672 GtC Schuur et al. 2008 Tarnocai et al., GBC, 2009

  8. Circumpolar & Tundra Soil Carbon Tarnocai et al., 2009

  9. REgional Carbon Cycle Assessment and Processes • RECCAP – www.globalcarbonproject.org/reccap • Objective: To “…establish the mean carbon balance and change over the period 1990-2009” for all subcontinents and ocean basins • 14 regions in the RECCAP synthesis: 10 terrestrial, 4 ocean regions • Achieved by a sythesis of bottom-up (observations and modelling) and top-down (inverse) modeling approaches Canadell et al., EOS, 2011

  10. RECCAP Arctic Tundra Chapter • Lead authors: Dave McGuire (Univ. Alaska), Torben Christensen (UL) • Approach: Compare estimates of C exchange in Arctic tundra from observations, process-based modelling, and atmospheric inversions, 1990-2006 McGuire, Christensen et al., submitted

  11. LPJ-GUESS Model Development • Numerical soil temperature and soil water freezing calculations • New shrub and open ground PFTs (Wolf) • New peatland hydrology and PFTs • Methane module • Modelled vegetation, ALD, soil temperature & CO2/CH4 fluxes agree satisfactorily with site and regional observations • LPJ-GUESS WHyMe now available Wania et al., 2009,2011; Miller et al., almost submitted

  12. LPJ-GUESS Simulations LPJ-GUESS Climate forcing WHyMe Peatland Output (m-2): Vegetation CO2 fluxes (NPP, NEE etc.) Carbon pools CH4 fluxes Upland Output (m-2): Vegetation CO2 fluxes (NPP, NEE etc.) Carbon pools Upland Peatland Tundra Gridcell

  13. RECCAP NEE & CH4 Observations NEE Neutral! CH4 • 250 estimates from 120 published studies • From a CO2 source in the 90s to a sink in the 2000s McGuire, Christensen et al., submitted

  14. RECCAP Observations McGuire, Christensen et al., submitted

  15. RECCAP Process-based Models 1990-99 2000-06 • LPJ-GUESS WHyMe, Orchidee, TEM6, TCF • From a small CO2 sink in the 90s to a greater sink in the 2000s McGuire, Christensen et al., submitted

  16. RECCAP Process-based Models- Seasonal Cycle - 1990-2006 2000-2009 2000-06 McGuire, Christensen et al., submitted • General agreement on seasonal cycle • Summer NPP is higher in the 2000s

  17. RECCAP Process-based Models- Interannual Variability- McGuire, Christensen et al., submitted • GPP; NPP & Rh highly correlated • NEP mostly uncorrelated

  18. RECCAP Process-based Models- Fire & CH4 Interannual Variability- McGuire, Christensen et al., submitted

  19. NEE From Inverse Models • Similar shape of mean seasonal cycle • Qualitative agreement with process models’ NEP McGuire, Christensen et al., submitted

  20. Arctic Tundra C Balance McGuire, Christensen et al., submitted

  21. The Future of the Tundra Carbon Balance?

  22. CARBO-North Domain CARBO-North study region T. Virtanen et al. 2004

  23. Climate Projections Mean Annual Temperature Annual Precipitation Warmer and wetter at all sites (A1B)

  24. Seida – Tundra Bog • Chamber and EC flux measurements of CO2, CH4 & N2O Photo: M. Repo

  25. Seida – Tundra Fen • Chamber and EC flux measurements of CO2, CH4 & N2O Photo: M. Repo

  26. Data: M. Johansson Abisko Birch Soil Temperature- Local Soil Properties -

  27. Wetland Hydrology • Granberg et al. (1999) Mixed Mire Water and Heat Model (MMWH) – hydrology part only • Soil column divided into acrotelm and catotelm • Daily precip., snowmelt, evapotranspiration, run-off & run-on determine water profile • Plants are never water stressed • Can use empirical EVP too • 10cm standing water allowed

  28. Abisko (Torneträsk) Active Layer Data: M. Johansson & J. Åkerman

  29. Modern Thaw Depths 1961-1990, LPJ-GUESS metre Miller et al., unpublished Tarnocai et al., GBC, 2009

  30. Treeline kgC/m2 Tarnocai et al., GBC, 2009

  31. Shrub & Open Ground PFTs Wolf et al. Clim. Ch. (2008)

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