Relationship between typhoon activity and upper ocean heat content

A 44-year mean distribution of tropical cyclone heat potential (TCHP), a measure of the oceanic heat content from the surface to the 26°C-isotherm depth, shows that TCHP is locally high in the western North Pacific (WNP). TCHP varies on interannual time scales and has a relationship with tropical cyclone (TC) activity. The third mode of an empirical orthogonal function analysis of TCHP shows that an increase in the total number of TCs is accompanied with a warm central Pacific and cool WNP. Negative TCHP anomalies in the WNP suggest that an increase in total number of TCs results in cooling due to their passages. On the other hand, the first mode shows that the number of super typhoons increases in mature El Niño years. An increase in accumulated TCHP is related to the increase in the number of super typhoons due to long duration. Copyright 2008 by the American Geophysical Union.