Comparison of Two Diagnostic Criteria for Rapidly Intensifying Tropical Cyclones over China's Offshore Waters

PENG Siyue; YAO Xiuping; ZHAO Dajun

doi:10.16032/j.issn.1004-4965.2025.020

Abstract：The sudden and destructive nature of rapidly intensifying tropical cyclones(TCs)over offshore areas has garnered considerable attention in research and operational forecasting.The mainstream criteria for identifying rapid intensification(RI)of TCs fall into two categories:changes in minimum central pressure and maximum wind speed.Utilizing the TC best-track dataset compiled by the Shanghai Typhoon Institute of China Meteorological Administration,the present study employed 12-h changes in minimum central pressure and maximum wind speed as diagnostic criteria to identify rapidly intensifying tropical cyclones(RITCs)offshore China from 1980 to 2019.The findings are as follows:(1)While both criteria yielded comparable RITC counts,case concordance rates were generally low,peaking in the 2010s(highest overlap)and reaching minima in the 2000s.(2)The criterion based on the 12-h maximum wind speed change exhibited higher sensitivity to variations in the time span of the data,with greater fluctuations in the corresponding RI thresholds.(3)The largest discrepancies in the RI samples identified by the two criteria were observed annually in the 1980s,monthly in September,and diurnally at 0600 Universal Time Coordinated.(4)Spatially,the 12-h maximum wind speed change criterion was more sensitive offshore northern Taiwan,southern East China Sea,and western Guangxi,whereas the 12-h minimum central pressure change criterion was more sensitive in eastern Guangxi waters.These findings provide operational guidance for RITC monitoring in China's offshore areas.