Increase in the Frequency of Tropical Deep Convective Clouds with Global Warming

Abstract. Deep Convective Clouds (DCC) are extreme rain events associated with large thunderstorms. They form in 0.6 % of the area of the tropical oceans. As the tropical oceans warm in a future climate, the frequency of occurrence of DCC may change. Between 2003 and 2016 the yearly mean temperature of the tropical ocean varied by almost 1 K. We use Atmospheric Infrared Sounder (AIRS) data for this time period to derive the probability of the DCC process as function of the Sea Surface Temperature (SST). The onset of the DCC process shifts about 0.5 K per 1 K of warming of the mean tropical SST. When these results are applied to the temperature distribution predicted by CMIP5 climate models for the end of this century, we find that the frequency of DCC, i.e. the percent of the area of the tropical oceans associated with DCC, which is 0.6 percent in the current climate, increases to 0.9 %, close to a 50 % increase.