Climatic Characteristics of Short-term Heavy Rainfall in Qujiang River Basin
Based on the hourly precipitation data of 14 national basic observation stations and 117 regional automatic stations in Dazhou,Bazhong,and Guang'an from 2009 to 2018,this paper analyzes the multi-scale spatial and temporal variation characteristics of short-term heavy precipitation frequency and hourly rainfall intensity extreme value in Qujiang River Basin.The results show that:(1)The frequency of short-term heavy precipitation in the Qujiang River Basin with a precipitation of≥50 mm/h is more than 10 times per year,and there is an increasing trend after 2014.(2)The monthly average number of short-term heavy precipitation events follows a unimodal distribution,with the peak occurring in July.(3)Short-term heavy precipitation mostly occurs from 02:00 to 08:00 with a significant char-acteristic of night rain.During the day,there is a secondary peak around 16:00 with the increase of temperature in the daytime.(4)Short-term heavy precipitation mainly occurs in the morning in spring,and it is not easy to occur during the day.The peak value in summer is around 06:00,and there is also a secondary peak in the afternoon during the day,with a valley value between 19:00 and 23:00.The peak value in autumn is in the morning,and the valley value is not obvious.(5)The average intensity of short-term heavy precipitation is between 28 and 29 mm/h,and there has been an increasing trend of short-term heavy precipitation above 40 mm since 2014.(6)The annu-al maximum hourly rainfall intensity mainly occurs from May to September,with the highest intensity in July and the second highest in-tensity in June.(7)The frequency of short-term heavy precipitation in the lower reaches of the Basin is less than that in the middle and up-per reaches.
Qujiang River BasinShort-term heavy precipitationClimateCharacteristics
NETL
NSTL
万方数据
