Net radiative heating and diagnostics of the diabatic circulation in the 15–110 km height layer

Abstract

The vertical and latitudinal structure of both net radiative heating and radiative equilibrium temperature in the 15–110 km height region has been calculated for solstice and equinox conditions. The monthly mean climatological fields of temperature and chemical constituents along with an accurate radiative algorithm were used. Solar heating due to O 3, O 2, CO 2 and H 2O and infra-red cooling due to CO 2, O 3, H 2O and NO were taken into account. Using the fields of net radiative heating and climatological data for temperature and the mean zonal wind, the diabatic circulation and eddy zonal accelerations were diagnosed. The interhemispheric transport regime at the solstice is shown to extend into the lower thermosphere, while at the equinox, the diabatic circulation has a more intricate multi-cell structure. The interhemispheric differences in the diagnosed fields are found in both winter and spring hemispheres. The distributions of eddy accelerations obtained for solstice conditions have two height maxima in the mesosphere and lower thermosphere for each hemisphere.