基于IMERG降水产品的台湾海峡非台风暴雨特征及成因分析OA

Using the Integrated Multi-satellite Retrievals for Global Precipitation Measurement(IMERG)precipitation products to fill in the gap of marine observations,the ERA5 reanalysis data are used to statistically analyze the spatial and temporal distribution characteristics of non-typhoon rainstorms in the Taiwan Strait,and the causes are derived from a classification and synthesis method.It is found that the rainstorms on the sea is the most in spring and June between 2016 and 2021.The areas with frequent annual rainstorm days and maximum daily extreme values are concentrated in the north and southeast of the strait.The 500 hPa situation on multiple monthly rainstorm days can be classified into the southwest wind type on the edge of the subtropical high and the convergence type in the east of the monsoon trough.Synthetic analysis shows that non-typhoon rainstorms occur under the favorable situation of high-level divergence,low-level convergence,cold and warm convergence,etc.Rainstorm prone areas are closely related to small and medium-sized low-level jet fluctuations and strait topography.We obtain conceptual models and forecast focus for two high occurrence areas of extreme heavy precipitation:the high occurrence area in the northern part of the strait and the southwest jet stream crossing the strait,forming a strong wind jet core correlation under various terrain conditions;The frequent occurrence area in the southeastern part of the strait is related to the strong convergence on the left side of the southwest jet stream passing through the Bashi Strait and the uplift in front of the mountains.