A statistical comparison of the potential intensity index for tropical cyclones over the Western North Pacific

Abstract

Abstract Potential intensity (PI), an upper thermodynamic limit of tropical cyclone (TC) intensity, is a useful index in TC statistical forecasting. This study evaluated the relationship between the current intensity of TCs and four PI indexes calculated with different sea surface indicators over the Western North Pacific (WNP) from 2009 to 2016. To mirror the degree of sea cooling caused by TCs, three sea surface temperature (SST) indicators (pre‐SST, 80 m depth mean sea temperature, and dynamic mixed mean sea temperature) were compared with real‐time SST obtained from HYbrid Coordinate Ocean Model (HYCOM) data. The results showed that four versions of PI all overestimated the current intensity of developing TCs. In contrast, when a TC at its strongest or in its weakening stages in a favorable atmospheric environment, pre‐sea conditions were strongly correlated with TC intensity. For strong TCs, the ocean‐coupled PI index was best able to describe TC intensity.

Keywords

• potential intensity
• sea cooling
• tropical cyclone