1. OC & BC 0.5° (ton) Eric F. Vermote 1,2, Evan A. Ellicott 1, Tatyana Laypyonok 3, Oleg Dubovik 4, & Mian Chin 2 1 Department of Geography, University of Maryland, USA; 2 NASA/GSFC; 3 Science Systems and Applications, Inc., Greenbelt, USA; 4 Laboratoire dOptique Atmospherique/USTL, Lille, France 1 Contact info: eric@ltdri.org Fire Radiative Power Relates to Biomass Fuel Consumption and Emissions Current estimates of emission loading from biomass burning are still uncertain (IGAC, IGBP) - Why? Emissions = burned area × fuel load × combustion completeness × emission factor Satellite derived estimates of Net Primary Production based on empirical relationships derived using a handful of field measurements Field based parameterizations based on fuel types and fuel moisture. No seasonal measurements of emission factors or combustion completeness. –Joint GOFC/GOLD Fire and IGBP-IGAC/BIBEX Workshop stated: Current approaches for estimating global emissions are limited by accurate information on area burned and fuel available for burning. An alternative approach to biomass burning emission estimates uses the measure of radiated energy liberated during combustion. First developed by Kaufman et al. (1998) and later refined and validated by Wooster et al. (2003, 2005), the integrated fire power (Figure 1), or fire radiative energy (FRE) can be used to estimate the fuel combusted (Figure 2) and thus emission loading. Fire radiative power can effectively estimate biomass burning emission loads on a global basis. Further refinement to characterize the fire cycle behavior and associated variation in emissions has been demonstrated for the savanna/shrubland biome using the MODIS CMG Aqua/Terra ratio as a surrogate for total energy. The next steps will include analyzing the fire cycle role in FRP based emission estimates for other landcover types. In addition, we plan to investigate the relationship between the Aqua/Terra FRP ratio and total fire energy (FRE) using SEVIRI and GOES. Figure 2. Relationship between fire radiative energy and fuel biomass combusted (Wooster et al., 2005) MODIS : Global observations of ambient aerosol AERONET : Semi-Global accurate observations of aerosol GOCART : Global aerosol simulations - assimilated meteorology - advection and convection - removal processes Main Uncertainty: aerosol sources Synergy of Observation and Modeling: Retrieving sources (location and strength) providing best agreement between observations of MODIS /AERONET and GOCART simulations To retrieve organic and black carbon particulate matter emissions from biomass burning, a combination of satellite and ground-based observations, along with chemical transport modeling, was used in concert with forward and inverse modeling. Goal: To Reduce Uncertainty in Current Biomass Burning Emissions Estimates Using Fire Radiative Power Figure 1. The MODIS Fire Radiative Power (FRP) global monthly climate modeling grid product (CMG) was used in this study. Organic and Black Carbon Aerosol Emissions From Fire – A Proxy for Total Biomass Burning Emissions Developing the FRP – Aerosol Emissions Relationship FRP CMG 0.5° (MW) Fossil Fuel Emissions OC & BC adjusted for anthropogenic sources OC & BC adjusted for anthropogenic sources (Cooke et al., 1999). The relationship was analyzed on a global basis for 2001. Using stratified regions developed by van der Werf et al. (2005), the Terra MODIS CMG product and the OC/BC particulate matter estimates were compared. Preliminary results show a strong relationship for many regions. However, even in regions with similar vegetation types, the emission factor (Eƒ) varies – Why? Investigation of Landcover as Source of Variation in Emission Coefficients – A Function of Diurnal Cycle SHAF: Eƒ = 0.0254 SHSA: Eƒ = 0.0247 NHAF: Eƒ = 0.0112 NHSA: Eƒ = 0.0698 We analyzed savanna/shrubland land cover – the dominant source of global fire activity and emissions: 750 million ha/year (Hao et al.,1990) 1/3 of global burning (Dwyer et al., 2000) 50%+ detected in Africa (Dwyer et al., 2000) SHAF Savannas Ef = 0.019 ****************** 2003-2005 Aqua/Terra = 3.383 BOAS Open Shrubland Ef = 0.042 ******************* 2003-2005 Aqua/Terra = 1.119 Differences in mean annual FRP Aqua/Terra ratio between regions points to variation in fire cycles, total fire energy released, and thus total emissions Aqua-Terra Ratio Explains the Variation Observed in Savanna/Shrubland Biome Emission Factor Regions with a significant portion of fire occurring in savanna/shrubland biomes were compared based on their respective Aqua/Terra FRP ratio. A strong relationship between the diurnal ratio and emission factor is obvious. It can be concluded that variation in regional emission factors of similar vegetation can be explained by the diurnal pattern of burning. In addition, the Aqua/Terra ratio can serve as a proxy for calculating total fire energy. Emission = Eƒ terra x Terra Energy Emission = Eƒ x FRE dt Emission = Eƒ (biome) x ƒ (Aqua/Terra) x Terra Energy Theory Demonstrated empirically Tested for Savanna/Shrubland Conclusions Proposed Global alternative approach for Fire emission estimate MODIS+AERONET Observations Observations from Retrieved emission Testing of emission inversion: GOCART reproduces observed aerosol using retrieved emissions Satellite derived estimates of burned area, though improving, may have an error of greater than 35%