  The proposition that the tropical cyclogenesis increases with the size of the
warm pool, the area enclosed by the 26C SST isotherm, is tested by comparing
the seasonal variation of the warm pool area with the seasonality of the number
of tropical cyclones. A non-linear relationship of high statistical
significance is found between the area and the number of cyclones, which may
explain both why there is no linear trend in the number of cyclones over time
and the recent upturn in the number of Atlantic hurricanes.
