Characteristics and influence factors of rapid intensification of tropical cyclones in the western north pacific

In this study, rapid intensification (RI) of tropical cyclone (TC) was defined as a maximum sustained surface wind speed increase of 15.4 m/s over a 24 h period, which was approximately the 95th percentile of 24 h intensity changes of TCs. By using the TC best-track data in the western North Pacific from the Joint Typhoon Warning Center, the basic characteristics of RI samples were studied, the effects of large-scale environmental factors on RI were discussed, and the RI probability was estimated. The results were as followings. The average duration of RI over the western North Pacific was thirty-three hours, and the longest duration was seventy-two hours. Almost all tropical cyclones that underwent RI reached typhoon intensity, and more than half of them became intense typhoons. Comparing to non-RI cases, the RI cases preferred forming in farther east and south regions with warmer water. No significant differences were found between the translational speeds of the RI and non-RI cases, 'out the RI cases had a