1. Distribution and Variation of Carbon Monoxide in the Tropical Troposphere and Lower Stratosphere
- Author
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Qian, Li, Hua-Feng, Shi, Ai-Mei, Shao, Jian-Chun, Bian, and Da-Ren, Lu
- Abstract
AbstractThe authors examine the distribution and variation of carbon monoxide (CO) in the tropics from the surface to the lower stratosphere. By analyzing space-borne microwave limb sounder (MLS) measurements, measurements of pollution in the troposphere (MOPITT) and modern-era retrospective analysis for research and applications (MERRA) meteorological products, and atmospheric chemistry and climate model intercomparison project (ACCMIP) surface emission inventories, the influences of atmospheric dynamics and surface emissions are investigated. The results show that there are four centers of highly concentrated CO mixing ratio over tropical areas in different seasons: two in the Northern Hemisphere and another two in the Southern Hemisphere. All of these centers correspond to local deep convective systems and monsoons/anticyclones. The authors suggest that both deep convections and anticyclones affect CO in the tropical troposphere and lower stratosphere — the former helping to transport CO from the lower to the middle troposphere (or even higher), and the dynamical uplift and isolation effects of the latter helping to build up highly concentrated CO in the upper troposphere and lower stratosphere (UTLS). Similarly, there are two annual surface emission peaks induced by biomass burning emissions: one from the Northern Hemisphere and the other from the Southern Hemisphere. Both contribute to the highly concentrated CO mixing ratio and control the seasonal variabilities of CO in the UTLS, combining the effects of deep convections and monsoons. Results also show a relatively steady emission rate from anthropogenic sources, with a small increase mainly coming from Southeast Asia and India. These emissions can be transported to the UTLS over Tibet by the joint effort of surface horizontal winds, deep convections, and the Asian summer monsoon system.
- Published
- 2014
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