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Iterations on LPJ surface fluxes Bremen April 6-7, 2009

Iterations on LPJ surface fluxes Bremen April 6-7, 2009. Isoprene Emissions H 2 uptake N 2 O fluxes SPITFIRE v2. Pru Foster Colin Prentice Lei Lei Dong Rita Wania Renato Spahni Catherine Morphopoulos.

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Iterations on LPJ surface fluxes Bremen April 6-7, 2009

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  1. Iterations on LPJ surface fluxesBremen April 6-7, 2009 Isoprene Emissions H2 uptake N2O fluxes SPITFIRE v2 Pru Foster Colin Prentice Lei Lei Dong Rita Wania Renato Spahni Catherine Morphopoulos

  2. Xu, X. et al 2008 Global Change Biology 14, 1651 “Convergence in the relationship of CO2 and N20 exchanges between soil and atmosphere within terrestrial ecosystems” Flux(N2O) = a + b Flux(CO2) N2O surface fluxes (Rita)

  3. Statistical parameters for linear relationship between N2O and CO2 N2O flux = slope * CO2 flux + interception

  4. Rice and crop masks Ramankutty et al LPJ fluxes multiplied by (1-fractional coverage)

  5. Nitrogen Fluxes from LPJ

  6. Nitrogen Fluxes from Xu et al

  7. Isoprene emission formulation GPP / 12 7 • I = e -------- x LAI • emission factor at STP PFT relative values taken from Guenther 2006, with reduction to broadleaves (Millet et al 2008 JGR) global value tunable (currently 1) x deviations from STP = ci,370 / ci exp ( 0.1 ( Tleaf - 30oC) ) GPP - gross primary productivity / 12 to convert gC / m2 /sec to moles CO2 /m2 / sec / 7 to convert moles CO2 to moles of isoprene Based on Arneth et al 2007 & Niinemets 1999

  8. T leaf Rnet, sw - l E 4 s Tday3 + r cp / rbh Tleaf = Tday + ------------------------------ Rnet, sw = net shortwave downward radiation = daily SW / day length * (1 - albedo) l E = latent heat energy loss through evapotranspiration r cp = volumetric heat capacity of air (1200 J / m3 / oC) rbh = boundary layer resistance to heat (s / m) = 5 s/m conifers; 40 s/m grasslands ; (Kelliher 1993 Oecologia) Goudriaan & van Laar 1994

  9. Global emissions LPJ 2002 Isoprene GOME 2002 HCHO

  10. Breakdown of components in isoprene emission estimate

  11. Breakdown of contributing elements to LPJ isoprene estimate

  12. Interannual isoprene emissions

  13. Hydrogen and Methane uptake model Surface flux = (Dsoil k )1/2 C0 Dsoil - diffusion coefficient in soil (cm2 / sec) k - oxidation rate, i.e. uptake, constant (s-1) C0 - H2 or CH4 concentration at the surface (cm-3) Masks - managed lands, wetlands, snow, NPP

  14. Diffusion coefficient

  15. Uptake rate within the soil

  16. Comparison of H2 fluxes from Amund

  17. New masks Snow mask Was: 0 if snow depth > 50 cm Now: following Price and Amund Sovde 1 1/2 1/4 0 20 40 60 cm Low organic matter mask if NPP < 10 gC / m2 uptake --> 0.

  18. New LPJ H2 fluxes New uptake rate versus other global

  19. Global uptake estimates LPJ uptake rates Smith-Downey’s thesis

  20. Latitudinal distribution of uptake

  21. Latitude bands versus Xiao’s satellite based inversions

  22. Burnt Fraction (ii) Spitfire GFED 1997 1998

  23. Month with peak burnt fraction Spitfire GFED Dec Nov Oct Sep Aug Jul Jun May Apr Mar Feb Jan 1997 1998

  24. Global Annual Burnt fraction

  25. SPITFIRE v2 improves estimates of the carbon cycle

  26. Transect at 25 East

  27. Averaged over 0 - 40E

  28. Future work • Historical detection and attribution runs As per McGuire et al 2001 using Ramankutty et al crop masks and estimating CO2, methane, fires, … • Future runs with 30 GCMs from either GSI or SRES futures to look at impacts on • H2, isoprene, methane, fires … • water resources • biodiversity • avoided deforestation

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