Characteristics of Spatio-temporal Distribution of Short-time Heavy Precipitation in Bijie City
Using the hourly precipitation data from eight national meteorological stations in Bijie City from 2006 to 2022,this article analyzes the relationship between the spatio-temporal distribution of short-time heavy precipitation and the rainstorm events in Bijie City from 2006 to 2022 by means of statistical diagnostic analysis and EOF.The results show that:(1)A total of 537 stations/times of short-time heavy precipitation occurred in the last 17 years,with an annual average of 31.6 stations/times,occurring more in the southeast and less in the northwest.Zhijin and Nayong were the places with high occurrence frequency of short-time heavy precipitation,while Hezhang had the least.The hourly rainfall of 87.9%short-time heavy precipitation processes was 20 mm≤R1h＜40 mm.(2)The interannual variation of short-time heavy precipitation shows an increasing trend,with the maximum value of 53 stations/times in 2019 and the minimum of 17 stations/times in 2013.Its inter-monthly variation shows a single-peak pattern,with May-September being the period of high frequency of short-time rainfall,peaking in July,characterized mainly by localized single-station rainfall.Its daily variation shows a single-peak pattern,occurring mainly in the nighttime,with the high frequency between 20∶00 and 04∶00 of the next day and the peak at 02∶00.(3)There were 327 rainstorm processes in total during the 17 years and 65.1%of the rainstorms were accompanied by short-time heavy rainfall,with the most rainstorms in July and the most rainstorms plus short-time heavy rainfall events in Zhijin.The correlation between rainstorms and short-time heavy precipitation amounted to 0.82.The spatial distributions of rainstorm days,rainstorm days accompanied by short-time heavy precipitation,and short-time heavy precipitation were all characterized by more in the southeast and fewer in the northwest.There was a significant positive correlation between the daily precipitation amount of rainstorms and the maximum rainfall intensity.These findings are of great significance for understanding and recognizing the climatic background of short-time heavy precipitation in Bijie City,and for improving the capacity of short-time heavy rainfall prevention and mitigation as well as the capability of nowcasting and early warning.
short-time heavy precipitationrainstormspatial and temporal analysiscorrelationBijie City
NETL
NSTL
万方数据
