Correlation between the Sea Surface Temperature and the frequency of severe storms in the tropical oceans using seven years of AIRS data

Abstract

The analysis of the daily count of Deep Convective Clouds (DCC) with cloud top temperatures colder than 210K and the zonal mean Sea Surface Temperature (SST) in large regions of the tropical oceans shows a correlation, which can be used to show that the frequency of DCC increases about 40% for each degree K increase in the zonal mean SST. This sensitivity is consistent with a simple model, which assumes that DCC have a high likelihood of forming in the tail of the zonal SST distribution where the local SST exceeds 302 K. Tropical zones with warmer SST have more locations with SST>302K, and consequently have a higher frequency of DCC. This model appears to be valid for a wide range of conditions, including the Tropical Warm Pool (TWP). DCC are associated with the most intense thunderstorms over the tropical ocean. The correlation between the zonal mean SST and the DCC frequency allows us to estimate the rate of increase of the frequency of intense thunderstorms in the tropical oceans due to global warming as 5%/decade.