We examine contributions from various source regions to global distributions and budgets of tropospheric ozone (O 3) in the context of intercontinental transport, using tagged tracer simulation with a global chemical transport model. For tagging O 3, we consider regional separation of the model domain on the basis of the distributions of O 3 chemical production. We define 14 polluted source regions (14 tracers) in the boundary layer (North America, Europe, China, etc.) and 8 regions (8 tracers) in the free troposphere; O 3 production in the remaining (remote) tropospheric region and O 3 transport from the stratosphere are also tagged as separate tracers. O 3 transport from the polluted source regions like North America, Europe, and Asia generally accounts for more than 40% of ozone abundances even in remote locations. O 3 exports from boundary layer in China and Asian free troposphere are discerned through much of the Northern Hemisphere, suggesting significant and extensive impacts of eastern Asian pollution. In particular, O 3 from Asian free troposphere plays the most important roles in distribution and seasonal variation of O 3 in the middle-upper troposphere almost globally. In June-September, the model calculates a large O 3 contribution (5-10 ppbv) from Asian free troposphere in the upper troposphere over the South Pacific associated with long-range interhemispheric transport from Asia to the southern midlatitudes (via the western Indian Ocean, Africa, and Atlantic) in the upper troposphere. O 3 transported from biomass burning regions such as South America, Africa, and Australia widely distributes in the Southern Hemisphere. Our simulation demonstrates that there is a significant interhemispheric O 3 transport from South America to the northern midlatitudes in the upper troposphere which reaches Japan, North Pacific, and the United States in conjunction with O 3 export from North Africa. Our tagged O 3 simulation estimates that the annual mean global tropospheric O 3 burden, as calculated to be 344 Tg in this study, comes from chemical production in the source regions (48%) and in the remote regions (29%) and from stratosphere-troposphere exchange (23%). Copyright 2007 by the American Geophysical Union.
CITATION STYLE
Sudo, K., & Akimoto, H. (2007). Global source attribution of tropospheric ozone: Long-range transport from various source regions. Journal of Geophysical Research Atmospheres, 112(12). https://doi.org/10.1029/2006JD007992
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