光化学2次元モデルによる対流圏オゾン変動

Abstract

A two-dimensional transport-chemistry model has been developed to access the annual cycles of the tropospheric ozone and its precursors. The indirect effects on ozone through wet removal of HO2 and CH3O2 radicals are of main interest.HO2 and CH3O2 radicals are moderately soluble, and their wet removal depresses the oxidation processes in the troposphere and may affect significantly in-situ photochemical production of ozone.To quantify the above effects by the two-dimensional model, temporal and spatial distributions of wet removal intensity are estimated with the global database for clouds and precipitation. Clouds are considered to serve as downward-only transport devices of the soluble tracers.The oxidizing capacity of the model troposphere is depressed by introducing washout terms for HO2 and CH3O2 radicals, and the modeled mixing ratio of ozone is reduced mainly at high latitudinal regions in Spring.