The Characteristics of Short-Time Strong Precipitation Distribution

Based on conventional ground automatic station observation data from 2008 to 2018. The result revealed the characteristics of short-time strong precipitation in Chongqing. (1) The high-frequency center of short-term heavy precipitations in Chongqing are local in Hechuan, Kaizhou, Wuxi and Yunyang and Wushan, all of which are adjacent to steep mountains. The orographic uplifting and special terrain have an increasing effect on precipitation. (2) The short-term heavy precipitation is mainly concentrated in June to August, and peaked in July. Monthly numbers of stations with 20-30 mm/h and 30-50 mm/h precipitations show the characteristics of reverse phase changes, the former is increasing first and then decreasing, and the latter vice versa; The main peak period of short-term heavy precipitations was between 00 and 08 BT, and the heaviest precipitation occurs between 3 and 5 o’clock, and the secondary peak period was between 15 and 18 BT. The precipitation intensity of the main peak period was significantly stronger than that of the secondary peak period. (3) Against the background of the southwest vortex, the precipitation intensity of highfrequency center in western Chongqing is much stronger than Youyang and Qianjiang as sub-centers in southeastern Chongqing, so the southwest vortex has a more significant impact on the short-term heavy precipitation in the western region, and June has the highest frequency of precipitation; The contribution of precipitation is the largest in the western and the main city of Chongqing, followed by the southwest, middle and east regions, and the least in Chengkou and Wuxi where the northeastern and Xiushan where the southeastern Chongqing. (4) The frequency distribution of short-term heavy precipitations at different altitudes is closely related to the number of stations. The frequency of short-term heavy precipitation at an altitude of 200-800 m accounts for 83% of the total frequency, and the maximum value of the extreme precipitation intensity also appears in this range. Outside this range, the frequency and the extreme value of precipitation intensity shows a clearly downward trend.