Terra Observations of Tropospheric Aerosol and CO from Biomass Burning David Edwards, Xuexi Tie, Louisa Emmons, and John Gille National Center for Atmospheric Research, Boulder CO, USA Allen Chu and Yoram Kaufman NASA Goddard Space Flight Center, Greenbelt MD, USA

Biomass Burning: Impacts on Tropospheric Chemistry and Climate Approximately half-billion hectares of natural and human-induced biomass burning occurs each year In tropical regions, biomass burning for cultivation, deforestation and savanna grazing is a major forcing mechanism for tropospheric photochemistry Fires emit large amounts of aerosol, CO, and hydrocarbons which strongly affect tropospheric O3 and the oxidising capacity of the atmosphere In addition to a climatic impact that is not well quantified, this also has implications for weather modification and air quality David Edwards, NCAR

Sept. 2000 MODIS Aerosol MODIS can distinguish between coarse and fine particles using multiple channels from the visible to the near IR Course aerosol mode: Mainly dust and sea salt Reflects in the VIS & NIR: Appears red in the VIS due to absorption in the blue Surface characterization is an issue over land Fine aerosol mode: Anthropogenic pollution and biomass burning Reflects mainly in the VIS Coarse mode (AOD) Fine Mode David Edwards, NCAR

MODIS Aerosol & MOPITT CO Sept. 2000 Good correlation is obtained between MODIS fine mode AOD & MOPITT CO Both CO and fine mode aerosol result from anthropogenic combustion processes: urban pollution, industry, and tropical biomass burning Fine Mode AOD MOPITT CO Column David Edwards, NCAR

South African & South American Plumes Southern African burning is a maximum in Sept.-Oct. Anti-cyclonic winds in southern Africa and the southern Atlantic result in strong re-circulations A stable mixing layer over Africa provides containment for several days Part of the African plume is advected into the Atlantic Periodically, the plume is advected south-east and caught in the westerly flow at higher southern latitudes Ten day trajectories starting 9-15-00 using HYSPLIT This an important mechanism providing for the long-range export of emissions In Brazil, strong convection lifts emissions to the mid troposphere The South American plume is advected south-east across the Atlantic The Atlantic becomes crossed by plumes moving in opposite directions David Edwards, NCAR

Prescribed burn near Kruger National Park, South Africa, September 7, 2000. Photo from the Convair-580 (Flight 1834) during SAFARI 2000 by Peter Hobbs, UWA. SeaWiFS true-color image acquired over Southern Africa, September 4, 2000. Data acquired by the Satellite Applications Center, Pretoria, South Africa. David Edwards, NCAR

MODIS Fine Mode AOD MOPITT 700 hPa CO AOD/CO Ratio Plume aging can be followed as the AOD/CO ratio falls, indicating persistent CO but reduced aerosol loadings due to the shorter aerosol lifetime David Edwards, NCAR

MOPITT CO total column, Oct. 1-15, 2000 Providing global context to local measurements: Long-range transport of biomass burning products October 1-15, 2001 MOPITT and ground-based FTIR CO total column measurements taken at Lauder, New Zealand. The plume from biomass burning causes a peak in the measured CO in the usually clean air over New Zealand FTIR data: N. Pougatchev, NASA & N. Jones, NIWA David Edwards, NCAR

MODIS AOD Fine Mode MOPITT CO Total Column David Edwards, NCAR

GOME NO2 Tropospheric Residual MOPITT CO Column TRMM/VIRS Fire Counts MODIS Fine Mode AOD GOME NO2 Tropospheric Residual MOPITT CO Column Satellite Observations of Biomass Burning and Resultant Plumes: Sept. 2000 Andreas Richter, U. Bremen David Edwards, NCAR

Effect of Aerosol on Ozone Production J[NO2] J[O3] Clear Sky BC Layer Effect of Aerosol on Ozone Production Black carbon from biomass burning strongly absorbs solar radiation and can potentially reduce photolysis rates within biomass burning plumes Reduction in photolysis can lead to a compensating offset to the expected increase in O3 production due to the higher concentrations of NOx, CO, and other hydrocarbons Heterogeneous reactions on BC particles can also affect O3 concentrations and the uptake coefficient for O3 on BC particles remains uncertain TUV photolysis rate calculation in a BC layer of AOD at 340 nm of 0.5 in the lowest 3km of the atmosphere David Edwards, NCAR

Summary The combination of measurements from the new tropospheric satellite sensors will play an increasingly important role in explaining chemistry and transport processes in the lower atmosphere This will be complimentary to continued in-situ measurements and modeling for sensitivity and process studies MOPITT CO and MODIS fine/coarse particle measurements can be combined to examine the seasonal variability and transport of aerosols and trace gases in biomass burning plumes Provides information about continental export and the impact of intense fire sources on global scale air quality Variations in plume relative composition for different burning regimes might potentially provide information about emission factors Detailed examination of O3 precursor emissions and transport, and the effect of BC on photolysis and heterogeneous chemistry is still required to quantify the impact on the tropical tropospheric O3 distribution David Edwards, NCAR