Transport Pathways of Fire Generated Tracers to the Upper Troposphere over South America and Africa: Analyses using A-Train satellite measurements

Agricultural burning and forest fires have a significant influence on the chemical composition of the upper troposphere as well as radiative forcing in the climate system. A clear understanding of convective and large-scale transport that carries fire produced tracers to the upper troposphere is needed as part of the effort to determine the response of the atmospheric constitutes to global environmental change. Identify the tracer transport pathways will also provide a basis for testing and ultimately improving our ability to model the chemical transport of fire generated pollutants. Satellite observations have shown that high carbon monoxide (CO) and aerosol concentration occur in the upper troposphere over South America and Africa regions during their peak biomass burning seasons from July to September. Through joint use of the A-train measurements, together with the NCEP reanalysis data and NOAA HYSPLIT trajectory model, we have found that the local convective pathway plays an important role above the continent surface where biomass burning and strong convection occur simultaneously, while convection followed by advection pathway dominates above the ocean surface. The back-trajectory analysis using HYSPLIT trajectory model shows simple advection pathways above 4km, while at lower level, transport pathway becomes complicated, mainly depends on horizontal and vertical wind direction, local convection and low-level jet stream.