A regional estimate of convective transport of CO from biomass burning

Abstract

We present a regional-scale estimate of the fraction of biomass burning emissions that are transported to the free troposphere by deep convection. The focus is on CO and the study region is a part of Brazil that underwent intensive deforestation in the 1980's. The method of calculation is stepwise, scaling up from a prototype convective event, the dynamics of which are well-characterized, to the vertical mass flux of carbon monoxide over the region. Satellite-derived observations of the area extent of pollution from biomass burning and convective cloud cover are used in the scaling. Given uncertainties in CO emissions from biomass burning and the representativeness of the protoype event, it is estimated that 10–40 percent of CO emissions from the burning region may be rapidly transported to the free troposphere over the burning region. These relatively fresh emissions will produce O₃ efficiently in the free troposphere where O₃ has a longer lifetime than in the boundary layer.