The effects of imposed stratospheric cooling on the maximum intensity of tropical cyclones

Using a cloud-resolving model, H. Ramsay presents results that elucidate the effect of stratospheric cooling and sea surface warming on the potential intensity (PI) of tropical cyclones in a recent article in the Journal of Climate. With fixed sea surface temperatures, cooling near and above the tropopause (~90hPa) is shown to increase PI at a rate of 1m/s per degree cooling. With fixed stratospheric temperatures, sea surface warming increases the PI by approximately twice as much, as a rate of about 2m/s per degree warming. These results have significant implications in terms of global tropical cyclone PI trends in response to climate change. Tropical sea surface temperatures have warmed by about 0.15K/decade since the 1970s, while the stratosphere has cooled anywhere from 0.3K/decade to over 1K/decade, depending on the data set used. Therefore, global PI trends in recent decades appear to have been driven more by stratospheric cooling than by surface warming. Find the full abstract here.