Policy Documents

Thermodynamic Control on the Climate of Intense Tropical Cyclones

July 8, 2009

In his 2009 paper published in Proceedings of the Royal Society, Dr. Johnny C. L. Chan studied five ocean basins—the Atlantic (1960-2007), the Western North Pacific (1960-2007), the Eastern North Pacific (1960-2007), the South Indian Ocean (1981-2007), and the South Pacific (1981-2007)—examining the relationship between the seasonally averaged maximum potential intensity (MPI, an index of thermodynamic forcing) over each basin and the frequency of occurrence of intense TCs within that basin. This work revealed, in Chan’s words, that “only in the Atlantic does the MPI have a statistically significant relationship with the number of intense TCs, explaining about 40% of the [observed] variance,” whereas “in other ocean basins, there is either no correlation or the correlation is not significant.”