Explainer: Limits on Hurricane Intensity

Kerry Emanuel MIT


Hurricanes derive their energy from the thermodynamic disequilibrium that exists between the tropical oceans and the overlying atmosphere. By taking into account both the rate and the efficiency with which this reservoir of heat energy can be converted into wind energy it is possible to derive a speed limit for hurricanes, which depends mostly on ocean and atmospheric temperatures. This speed limit is in good accord with the results of computer simulations of hurricanes, but in nature, interaction of tropical cyclones with their atmospheric and oceanic environment limits the intensity of most (but not all) storms to values well below the theoretical limit. Nevertheless, limit theory is useful for estimating the most intense storm like to strike a given area over a reasonably long period of time.