Impact of ocean warming on the tropical cyclone size and destructive potential

How tropical cyclone (TC) destructive potential depends on ocean warming is a open issue. Previous studies ignored the effect of TC size change due to ocean warming, which results in a significantly underestimate of TC destructive potential. Here we use a regional atmospheric model to explore the response of TC size and destructive potential to sea surface temperature (SST) increase. We find that the simulated TC size increases significantly as the SST increases, which contributes greatly to the TC destructive potential. Physical mechanisms responsible for the dependence of TC size on SST are investigated. A further study of relative roles of the inner and outer SST warmings shows that they contribute oppositely to the change of TC intensity and size through their effects on the air-sea temperature and specific humidity difference and the portion of energy inputted into TC eyewall and outer spiral rainbands. As a result, the competition between the effects of inner and outer SST warming plays a critical role in determining the overall TC intensity, size and destructive potential. Numerical model results demonstrate that, assuming a warming ocean, TC will become not only stronger, but also larger, and thus more destructive in future.