J. Geophys. Res. (1997), 102, pp. 23,883--23,894.
This paper investigates the influence of radiation on the evolution of an idealized upper tropospheric anticyclone focussing on the tropopause behaviour and stratosphere-troposphere mass exchange. A realistic radiation scheme is implemented in an axisymmetric Eliassen-balanced vortex model. A number of numerical integrations are performed starting from an upper tropospheric anticyclone as initial state. For average midlatitude conditions the secondary cross-vortex circulation induced by the radiative heating and cooling is such that the vertical wind is almost zero near the tropopause. Nevertheless, the tropopause in the center of the anticyclone is displaced downward by about 1.5 km within 10 days of integration, resulting in a substantial transfer of mass from the troposphere to the stratosphere. One part of the diabatic heating, which is responsible for the cross-tropopause mass transfer, is due to the temperature anomalies in the center of the anticycone, while another part should be attributed to the suppression of convection there. The amount of mass transferred across the tropopause is sensitive to the structure and the strength of the upper tropospheric temperature anomalies and, especially, to humidity close to the tropopause, with upper tropospheric and lower stratospheric humidity playing rather different roles. The cross tropopause mass transfer does not sensitively depend on the definition of the tropopause.