FREE TROPOSPHERIC OZONE PRODUCTION AFTER DEEP CONVECTION OF DISPERSING TROPICAL URBAN PLUMES

Ozone generation is computed in a one-dimensional photochemistry code following convective redistribution of tropical urban effluent into th e free troposphere. Simulations are run at several stages of pollutant dilution by surrounding surface air. A threshold boundary layer NOx c oncentration of 300 pptv is established for significant production enh ancements at upper levels. Areas defined by the 300 pptv level are exa mined in the Gaussian dispersion framework based on a wet season plume event observed in Amazonia. Pollution travels slowly in the sluggish winds of the equatorial trough. Daily storms are likely to interrupt t he effluent while coverages are still on the order of few thousand squ are kilometers and NOx concentrations are above the threshold. Dry sea son plume sizes are difficult to assess because local concentration da ta are scarce, but it is conceivable that the faster trade winds lead to a several fold extension. Copyright (C) 1996 Elsevier Science Ltd