Geographical distribution and seasonal variation of surface emissions and deposition velocities of atmospheric trace gases


  • Jean-François Müller


The geographical distributions on the global scale of trace gas surface emission and deposition are established on the basis of a variety of technical, geographic, and climatic data. The 5° × 5° resolution maps of the sources and deposition velocities are constructed, which can be used as surface boundary conditions in a three-dimensional chemical/transport model of the troposphere. Special attention is devoted to emissions of CO, NOx, and several nonmethane hydrocarbons (NMHC) and to the fossil fuel emissions of methane. Anthropogenic sources, i.e., the emissions produced or controlled by human activities, represent about 75% or more of the total surface emissions of CO, CH4, SOx and NOx and about two thirds of the total production of atmospheric CO (from surface sources and atmospheric oxidation of hydrocarbons). The possibility arises that methane releases from natural gas exploitation in the USSR are substantially larger than accounted for in previous studies, implying possible important consequences for the methane budget.