Rain clusters identification and characteristics analysis of regional rainstorms in Hubei Province

Based on the hourly precipitation data from April to September of 2008-2017 in Hubei Province, the 141 regional storms were selected; on the basis of this, the OPTICS spatial clustering algorithm was used to identify 2586 precipitation clusters and process 936 rain masses. According to the definition of mesoscale rain clusters, 489 mesoscale rain clusters were identified, including 314 mesoscale stationary rain clusters and 175 mesoscale mobile rain clusters; analysis of the characteristics of mesoscale rain clusters yielded: 1) the duration frequency ratio of mesoscale stationary rain clusters decreases with time, the peak value is 2 h, and the duration of mesoscale mobile rain clusters is single-peak type, mostly concentrated in 3-6 h. 2) The large value areas of mesoscale stationary rain masses are Enshi Autonomous Prefecture and Wuhan City, and the second largest value is in Yichang and northern Xianning. Meso-scale moving rain masses are mainly distributed at the junction of Wuhan and Xiaogan, Enshi Autonomous Prefecture, and Yichang. 3) The k-mean clustering of mesoscale mobile rain cluster paths can be obtained. There are three types of mesoscale mobile rain cluster paths: eastern, southwest and northwest. And they mostly move to the northeast and southeast direction.