Threshold Values and Spatio-temporal Distribution of Short-time Heavey Precipitation in Tongren City
This article analyzed the extreme thresholds and distribution characteristics of short-time heavy precipitation in Tongren region by using the daily and hourly precipitation data of 10 national weather stations in Tongren region from March to November of 2006-2022.The precipitation extremes and sub-extremes of 1 h,2 h and 3 h were selected separately and arranged in ascending order,the threshold values were determined comprehensively based on the basic method of the 95th percentile,and their distribution characteristics were determined by conventional statistical results.The analysis results indicate that the precipitation≥25 mm in 1 h,≥40 mm in 2 h and≥50 mm in 3 h can all be used as the thresholds of short-time severe precipitation in Tongren region,where Songtao is the largest value center of short-time heavy precipitation and Jiangkou is the second largest value center.June is the month for the five counties in the west of Tongren and the Wanshan County in the east to have high frequency of short-time severe precipitation,but for the Songtao County,Bijiang District and Yuping County in the east,July is the month to experience short-time severe precipitation most frequently,while Jiangkou County has most frequent short-time severe precipitation in August.In Tongren,the short-time heavy rainfalls mainly occur from May to August,accounting for 84.4%of the annual total days,and 67.3%of the short-time heavy rainfalls occur at single stations,which shows the locality features obviously.In addition,short-time heavy precipitation mainly occurs at night in Tongren region,especially in Jiangkou County.The ratio of nighttime frequency of short-term heavy precipitation to the total frequency of short-term heavy precipitation is 84.9%,and the ratio of nighttime heavy precipitation to the total amount of short-term heavy precipitation reaches 86.5%.The night rainfall feature of short-time severe rainfall is more obvious than the total precipitation.In summary,this study has made a useful exploration for understanding the short-time heavy precipitation in Tongren region,and provides a guidance for formulating the ＂three responses＂indexes of severe precipitation as well as preventing disasters and reducing damages.
GB/T 33669-2017 improvementthreshold of short-time severe precipitationshort-time severe precipitation eventspatial and temporal distribution
NETL
NSTL
万方数据
