Temporal and spatial characteristics of activities and potential destructiveness associated with tropical cyclones crossing Jiangsu Province

In this study 67 tropical cyclones (TCs) crossing Jiangsu Province are identified from a total of 2440 western North Pacific TCs during the 73-yr period of 1949-2021, using the best-track data archived at the China Meteorological Administration’s Shanghai Typhoon Institute (CMA STI). Temporal and spatial characteristics of activities and potential destructiveness associated with TCs crossing Jiangsu Province are investigated. Results show that TCs crossing Jiangsu Province, which mainly and widely generated in July and August, account for 2.7% and 10.2% of TCs over the western North Pacific and those making landfall in China, respectively. TCs crossing Jiangsu Province make landfall in China mainly in June–November from genesis through entering Jiangsu, with highest landfalling frequency and widest landfalling distribution in August. The landfalling routes of TCs crossing Jiangsu are categorized into 14 types (T1~T14), of which route T4 that make landfall first in Taiwan and then in Fujian account for the highest proportion. The tracks of TCs crossing Jiangsu are classified into four types. The moving directions within Jiangsu and overall track morphologies of TCs in these four types are closely related to the westward extension and northward shift of the western North Pacific subtropical high. TCs enter and leave mainly from the southeast and east coast of Jiangsu, respectively, in July–September. The entering locations of TCs crossing Jiangsu shift northward from June to August and retreat southward in September–October, while leaving locations shift westward and then retreat eastward, due to seasonal adjustments of large-scale systems, such as the western North Pacific subtropical high and monsoon circulation. The track density of TCs in Jiangsu generally decrease from southeast to northwest, with most of the TCs moving northward or northeastward. The spatial distributions of track density and average velocity vectors of TCs crossing Jiangsu are characterized by significant monthly variations. There is a significant increase in potential destructiveness of TCs in Jiangsu (JS-PDI) during the period of 1949-2021, corresponding to increases in their landfall intensity and average intensity in Jiangsu. The JS-PDI in August is considerably higher than in other months. In agreement with the distribution of average TC intensity in Jiangsu, larger JS-PDI values are mainly distributed in the coastal region and southeast of Jiangsu, and the locations of maximum JS-PDI and track density are well matched.