Latitudinal distributions of trace gases in and above the boundary layer

Abstract

Statistical analyses of global atmospheric concentrations provide evidence that C 2Cl 4, CHCl 3 and CH 3CCl 3 (methylchloroform) are more abundant in the tropical boundary layer than above it ( α ⩽ 0.09) by 27% (±27%), 21% (−21%, +12%) and 6.4% (±6%) respectively. The air samples on which these results are based were collected by cryogenic techniques during the June 1978 project GAMETAG flights and analyzed soon afterwards by gas chromatography (EC/GC and GC/FID), thus providing latitudinal concentrations of CO, CH 4, CCl 3F, CCl 2F 2, CH 3CCl 3 and light C 2-hydrocarbons, both in and above the boundary layer. In August 1980, after further development of analytical techniques, the stored air samples were re-analyzed to establish the latitudinal distributions of CH 3I, CHCl 3, C 2Cl 4, C 2F 3Cl 3 (F-113) and CHClF 2 (F-22) in and above the boundary layer. Stability studies, spanning a year, show that the concentrations of these gases do not change in the flasks.