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Report on progress made towards next set of fire deliverables

St. Petersburg Meeting. Work Package 1: Changes in terrestrial carbon and water fluxes. Report on progress made towards next set of fire deliverables. Photosynthesis. Gross Primary Production (GPP). 120. Plant Respiration. Net Primary Production (NPP). 60. Soil Respiration.

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Report on progress made towards next set of fire deliverables

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  1. St. Petersburg Meeting Work Package 1: Changes in terrestrial carbon and water fluxes • Report on progress made towards next set of fire deliverables

  2. Photosynthesis Gross Primary Production (GPP) 120 Plant Respiration Net Primary Production (NPP) 60 Soil Respiration Net Ecosystem Production (NEP) 5 Disturbance Flux Net Biome Production (NBP) 2 Gt C Global Carbon Fluxes

  3. NBP Representation in 3 Models NBP (Mt C) 20-year Average, 50°- 75°N, Pan-Boreal LPJ SDGVM •Model average over the past 25 years shows that the region is a sink in agreement with the general consensus regarding high latitudes. •All 3 models agree on magnitude of NBP. CLM4 NBP in Tg C

  4. Trend in NBP (Tg C) NBP (Tg C) 1981-2006, 50°- 75°N, Pan-Boreal •All models show positive trends, only SDGVM is statistically significant at a 95% confidence interval.

  5. ECV: Carbon Emissions (Mt C) Carbon Emissions (Mt C) 20-year Average, 50°- 75°N, Pan-Boreal LPJ SDGVM •LPJ has ~x2.5 higher carbon emissions. •Despite similar NBP, fire emissions show significant differences. •The GFED carbon emissions data set should be cautiously used. CLM4 C Emissions in Tg C

  6. Carbon Balance in Models Carbon Balance (gC) 20-year Average, 50°-70°N, Pan-Boreal •Magnitude and nature of NBP makes models extremely sensitive to any disturbances such as fire and deforestation.

  7. ECV: Burned Area GFED % of Area Burned, 2004 LPJ % of Area Burned, 2004 •Models don’t capture the stochastic nature of fire. •They burn the majority of the grid cells by a small percent, usually less than 1%, and cumulatively agree with the data sets.

  8. ECV: Burned Area Burned Area (%) 20-year Average, 50°- 75°N, Pan-Boreal LPJ SDGVM •Burned area in models is a function of litter, moisture and temperature. •GFED burned area data set can be used as reference. CLM4 Burned Area in MHc •SDGVM burns ~50% more area.

  9. Fuel Load in Models Fuel Load (Mt C) 20-year Average, 50°- 75°N, Pan-Boreal LPJ SDGVM •SDGVM doesn’t burn the litter. •LPJ has complete combustion. •SDGVM doesn’t accommodate for plant fire resistance. •CLM doesn’t burn over a certain latitude. CLM4 Fuel Load in Tg C

  10. Fire Regime in Models Burned Area in MHc Fuel Load in Tg C •No two models describe the fire regime in the same manner. •Still all converge to similar NBP values. •Systematic Biomass ECV can reduce uncertainties. C Emissions in Tg C NBP in Tg C

  11. St. Petersburg Meeting Work Package 1: Changes in terrestrial carbon and water fluxes • Actions from Toulouse Meeting

  12. Recap of Toulouse Meeting N. America •Examined several land cover products. •Transformed land cover data sets into Vegetation Continuous Fields for comparison. Eurasia

  13. Land Cover by Latitude Bands N. America Eurasia GlobCover GLC2000

  14. Land Cover by Latitude Bands Trees Herbaceous Bare Ground Eurasia N. America Key Messages: •Driving the models with different land cover data sets cause the NBP to differ by up to 30%. •Water fluxes remained largely unchanged.

  15. Permafrost LPJ Thaw Depth (cm) Different Approaches: •In CLM4 permafrost follows an annual sinusoidal cycle of air temperature. •LPJ numerically solves the heat diffusion equation.

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