Effect of tropospheric temperature change on the zonal mean circulation and SH winter extratropical cyclones

Abstract

This study aims to understand the mechanisms which cause an overall reduction of SH extratropical cyclone activity with a slight increase in the high latitudes in a warmer climate simulated in general circulation models (GCMs) with increasing CO2. For this purpose, we conducted idealized model experiments by forcing warm temperature anomalies to the areas where climate change models exhibit local maximum warming - the tropics in the upper troposphere and the polar regions in the lower troposphere - simultaneously and separately. The Melbourne University atmospheric GCM (R21) coupled with prescribed SST was utilized for the experiments. Our results demonstrate that the reduction of SH extratr..