Analysis on Precipitation Extremes and Characteristics of the Rainstorm Event in the West of Hexi Corredor

Abstract

An extremely heavy rainstorm occurred 20:00 on 12 to 20:00 （Beijing Time） on 13 August 2022 in Jinta， Gansu Province， the 24 hours cumulative precipitation and hourly precipitation at Jinta station broke the historical extreme values.Based on the minutely， hourly and daily precipitation observation data， as well as the CMA Multi-source Merged Precipitation Analysis System （CMPAS） hourly precipitation data， the precipitation characteristics and extremity of the torrential rain event were analyzed.The results show that the extremely torrential rain event is characterized by large cumulative precipitation， strong locality， strong short-term precipitation and obvious convection.The main precipitation period is night and the rainstorm center is located in Jinta county， Jiuquan city.There are 11 stations reached the maximum since the station establishment， among which， the maximum appeared in Jinta station， reaching 88 mm， which is the second largest observed of all national stations in Jiuquan city， exceeding 58% of the historical average of the flood season in 62 years （from 1961 to 2022）.There are 13 stations’s hourly precipitation reached the maximum since the station establishment and the maximum hourly precipitation of Jinta station was 56.2 mm， ranking the first among all the stations in Jiuquan， nearly three times of the average rainfall in August in Jinta Station in the past 62 years， showing obvious historical extremes.There are three precipitation periods in Jinta Station， and the heavy precipitation mainly occurs in the second period， with strong minutely precipitation intensity and long duration.The heavy precipitation center first appeared in the southeast of Jinta station， and then moved to the northwest， with the range of heavy precipitation expanding.After three hours， the precipitation intensity weakened and moved out to the southeast， and the precipitation process in the rainstorm area ended.

Keywords

• rainstorm in arid areas
• extreme precipitation
• convection
• minutely precipitation