题目：Synoptic Analysis of Extreme Hourly Precipitation in China Mainland and Taiwan
报告人：罗亚丽 研究员（中国气象科学研究院 ）
邀请人： 赵坤 教授
In this study, synoptic situations associated with extreme hourly precipitation over China mainland and Taiwan, respectively, are investigated. All the extreme precipitation records are classified into four types according to the synoptic situations under which they occur, i.e., the tropical cyclone (TC), front, vortex/shear line, and weak-synoptic forcing types.
In China mainland, there are 5797 extreme precipitation records in 2011-2015, among which 39.1% is related to a low-level vortex/shear line, 13.9% is associated with a front, 8.0% is caused by TCs, and 39.0% occurs under largely quiescent synoptic conditions. The TC-type occurs most frequently along the coasts and decreases progressively toward inland China; the frontal type is distributed evenly east of 104oE; the vortex/shear line type shows a prominent center over the Sichuan Basin with two high frequency bands extending from the center southeastward and northeastward, respectively; the weak-synoptic type occurs more frequently in the southeast China, southwest China, the north China, and east portion of the northeast China.
In Taiwan, the TC type accounts for over three quarters of the total records, while the front-type and weak-synoptic forcing type are comparable (9-13%). The TC type is further divided into seven subtypes according to the distance and location of the TC center relative to the island. When the TC center is over the island or near the coastline (<100 km), the spatial distribution of subtypes I-IV is largely determined by the azimuth of the TC center relative to the island. When the TC center is far away (>100 km) from the island, the spatial distribution of subtypes V-VII is determined by the interaction between the TC circulation and the environmental southwesterly or northeasterly winds.