Monday, 23 January 2012
Role of Transport Pathways in Determining CO Centers in the Tropical Upper Troposphere
Hall E (New Orleans Convention Center )
Poster PDF (325.6 kB)
Past studies have suggested that fire generated carbon monoxide (CO) in the tropics was transported to the upper troposphere (UT) via different pathways, including the “local convection”, “UT advection” and “lower troposphere advection → convection” pathways. However, the relative importance of these transport pathways in determining the locations and seasonality of the CO centers in the tropical UT remains unclear. We developed a multi-satellite-based approach to identify CO transport pathways and their geographic and seasonal distributions for the period of 2004-2009, through joint use of Aura MLS CO observation, the Global Fire Emission Database and TRMM data. The results suggest that seasonality of the CO centers in the tropical UT does not follow those of CO surface emission and convection. Rather, it mainly follows the seasonality of “local convection” transport pathway. The occurrence of this pathway peaks in boreal spring in the northern hemisphere and fall in the southern hemisphere, respectively, when deep convection overlaps with CO surface emission. These semi-annual peaks of the “local convection” transport contribute to the high CO concentration in the tropical UT during boreal spring and fall seasons.
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