A multi-year effort is assessing the extent of agricultural and wildland burning in tropical forest and savanna of central Brazil, quantifying the magnitude of fire emissions to the atmosphere, and evaluating the impacts of these emissions as a source of regional air pollution. Emission estimates will contribute to the official Brazilian Government position on the importance of burning as a source of greenhouse-gases in the atmosphere. An areal estimate of emissions for trace gases such as methane or nitrous oxide is derived from the time-integrated product of

(i) the areal growth rate of fires (hectares burned per week during the dry season from July through September),

(ii) the rate of carbon loss or biomass consumption per unit area (sampled across different ecosystems), and

(iii)the mass of trace gas emitted per mass of fuel-carbon lost to the atmosphere.

Satellite and aircraft-based remote sensing from both Brazilian and U.S. aircraft are being used to track rates of fire occurrence, estimate fire areas and impacts, and supply fire information for management action. Carbon loss has been assessed directly at the ground and from airborne measurements within organized smoke plumes. These measurements are being related to remote sensing measures of fire area growth, fire temperature, and flaming zone structure to provide a remote estimator of the carbon and energy flux from entire fires. Trace gas emissions per unit of carbon lost have been estimated by plume sampling and statistically modeled as a function of the plume concentrations of carbon monoxide and total carbon. Taken together, these provide the most sophisticated tools and models yet available for monitoring wildland fires.

A Brazilian meteorological aircraft penetrated this plume on several occasions in 1994 to measure concentrations of smoke particles and trace gases. The fire plume generated a large capping cumulus cloud and inserted most of the particulates above the planetary boundary layer.