HR: 1330h
AN: A22C-1076    [PDF]
TI: Space-Based Observations of the Seasonal Variations in Biomass Burning Emissions of NOx and VOCs over Africa during 2000
AU: * Jaegle, L
EM: jaegle@atmos.washington.edu
AF: Department of Atmospheric Sciences, University of Washington, BOX 351640, Seattle, WA 98195 United States
AU: Steinberger, L
EM: llou@atmos.washington.edu
AF: Department of Atmospheric Sciences, University of Washington, BOX 351640, Seattle, WA 98195 United States
AU: Martin, R V
EM: Randall.Martin@Dal.Ca
AF: Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 3J5 Canada
AU: Chance, K V
EM: kchance@cfa.harvard.edu
AF: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 United States
AU: Kurosu, T P
EM: tkurosu@cfa.harvard.edu
AF: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 United States
AU: Palmer, P I
EM: pip@sol.harvard.edu
AF: Division of Engineering and Applied Sciences, Harvard University, Pierce Hall, 29 Oxford Street, Cambridge, MA 02138 United States
AU: Chin, M
EM: chin@rondo.gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Code 916, Greenbelt, MD 20771 United States
AB: We use tropospheric NO$_{2}$ and HCHO columns from the Global Ozone Monitoring Experiment (GOME) satellite instrument to map the spatial and seasonal variations of NO$_{x}$ and volatile organic compounds (VOC) emissions over Africa during 2000. Our tropospheric column retrievals include the local effects of aerosols, clouds, as well as shape factors for NO$_{2}$ and HCHO from the GEOS-CHEM global 3-D chemical transport model. The GOME NO$_{2}$ columns display a very strong biomass burning signal with the well-known seasonality: fire season in Northern (Southern) Africa between November and March (May and October) with a north to south (northwest to southeast) progession. In addition, a strong signal from biogenic NO$_{x}$ emissions is present throughout the wet season, with particularly high NO$_{2}$ columns in June over North Africa. Elevated GOME HCHO columns are observed over biomass burning areas, as well as over the tropical forests of central Africa (indicating strong biogenic isoprene emissions). We derive a top-down NO$_{x}$ emission inventory from the GOME column NO$_{2}$ observations through an inversion with the GEOS-CHEM model. Our estimate of annual surface NO$_{x}$ emissions is 8 Tg N yr$^{-1}$ over Africa for 2000 (4.1 and 3.9 Tg N yr$^{-1}$ for North and South Africa, respectively), which is $50%$ larger than our bottom-up GEOS-CHEM emission inventory. Most of the difference is attributed to stronger than expected biogenic NO$_{x}$ emissions from soils, as well as to too low NO$_{x}$ emission factors used in the GEOS-CHEM model for North African Savannas. We will use space based observations of active fires (ATSR, VIRS) and burned areas (GBA2000) to separate biomass burning from biogenic emissions of NO$_{x}$ and VOCs, and examine their respective spatial and temporal variability during 2000. In addition, we will compare the GOME observations and GEOS-CHEM model results to studies from the SAFARI 2000 field mission over Southern Africa.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting