A Reduction in Global Tropical Cyclone Frequency due to Global Warming

Abstract

In this report, we present the results from our recent experiments using 20 km-mesh and 60 km-mesh atmospheric general circulation models with prescribed sea surface temperatures (SST). The results of the experiments consistently show a reduction in the global tropical cyclone frequency due to global warming. By the experiments with the models of different resolution and with different SST changes, we find that the reduction in the global tropical cyclone frequency due to global warming is a very robust feature. In contrast, the regional tropical cyclone frequency change varies a lot among the experiments with different SST change distribution. We find that the regional tropical cyclone frequency change is sensitive to relative SST change distribution. This suggests that the regional change is strongly affected by the change in tropical circulation and convective activity which is dominated by relative SST distribution patterns, and therefore, for a reliable projection of the regional change, a reliable projection of the pattern of SST change is vitally important.