Tropical Cyclones and the Upper Ocean

There are seven basins where tropical cyclones (TC) occur on a regular basis. According to NOAA's National Hurricane Center, approximately 69% of all TC occur in the Northern Hemisphere, while only 31% can be found in the Southern Hemisphere. Approximately 12% of TC occur in the Atlantic Ocean, 57% in the Pacific Ocean and the remaining 31% in the Indian Ocean.

Several events have been registered where TC suddenly intensified when their path traveled over oceanic warm features, such as anticyclonic rings and eddies. It is now known that the ocean thermal structure plays an important role in TC intensification. Therefore, the monitoring of the upper ocean thermal structure has become a key element in the study of the hurricane-ocean interaction with respect to the prediction of sudden TC intensification.

A methodology than incorporates satellite and hydrographic observations is used to estimate daily fields of upper ocean heat content from the sea surface to the depth of the 26°C isotherm, which we refer to here as Tropical Cyclone Heat Potential (TCHP).

TCHP fields are used operationally for intensity forecast by the Navy's Joint Typhoon Warning Center. Similar fields created at the National Hurricane Center are used for intensity forecast in the North Atlantic, Caribbean Sea and Gulf of Mexico.