Characteristics of Precipitation in China Associated with Tropical Cyclones over the Bay of Bengal

In comparison with the number of studies into the impact on precipitation in China of tropical cyclones (TCs) over the western North Pacific, investigation of the effect of TCs in the Bay of Bengal (BoB) on precipitation in China is lacking. In this study, precipitation in China associated with TCs over the BoB was divided into direct rainfall induced by TC cloud clusters and indirect rainfall related to the long-distance transport of TC water vapor. We partitioned the BoB TC-related rainfall that occurred during 2000–2018 in China and analyzed its statistical features. It was found that 40 of the 67 (60%) TCs that occurred over the BoB exerted influence on rainfall in China. Direct rainfall was mainly distributed over the southeastern Tibetan Plateau and Southwest China, while indirect rainfall was distributed widely with two high-value centers: one over Yunnan Province and the other over the area south of the middle–lower reaches of the Yangtze River. The highest mean daily rainfall amount of direct TC precipitation appeared in northern Yunnan Province and southeastern Tibet, while that of indirect TC precipitation occurred eastward of 110°E. During the bimodal period of peak occurrence of BoB TCs in May and October–November, the annual mean amount, intensity, and number of days of rainfall in China related to BoB TCs were generally greater in May, e.g., the mean daily rainfall amount was twice that in October–November, except at stations in southeastern Tibet. In comparison with the BoB TCs that induced heavy rainfall in China in early summer, the TCs in autumn had a more southwestward mean position and a more asymmetric structure, with the long axis oriented in the northeast–southwest direction. Heavy rainfall induced by BoB TCs occurred mainly over southeastern Tibet and provinces south of the middle–lower reaches of the Yangtze River in early summer and over Yunnan and Sichuan provinces in autumn, mostly in response to circulation patterns of a “northern trough with a southern TC” and of “convergence of two high pressure systems,” respectively.