基于分钟降水数据的长沙市场次降水事件特征分析

Characteristic analysis of precipitation events in Changsha city based on minute rainfall data

采用长沙市1980-2017年的分钟降水数据,开展降水场次随间歇时间变化的敏感性分析,确立降水间歇时间为240 min,分3-11、3-6、7-9月3个时间段从降水场次与过程降水量、开始时间、结束时间、持续时间、间歇时间等5个方面进行长沙市场次降水事件特征分析。分析表明:长沙3-11月年平均出现121次降水事件,3-6月出现68次降水事件,7-9月出现32次降水事件;降水事件开始时间与结束时间随不同季节及降水量阈值呈现不同的日变化特征;降水持续时间在1 h以内的最多,有76%集中在12 h以下;间歇时间在12 h以下的为46%,超过24 h的降水事件占39%。

Using minute precipitation data from 1980 to 2017 of Changsha,the sensitivity of changes in precipitation events with time interval was experimented.On the basis of the establishment of precipitation interval 240 minutes,the characteristics of precipitation events in Changsha were analyzed for five aspects including the rainfall occurrence and amount,the start time,end time,duration,and break interval from March to November,March to June,and July to September.The analysis shows that there are about 121 precipitation events from March to November and 68 precipitation events from March to June and 32 precipitation events from July to September.The start time and end time of precipitation events show different daily variation characteristics with different seasons and rainfall thresholds.The duration for most precipitation events is less than one hour and 76%is below 12 hours.The frequency of events with break interval less than 12 hours is about 46%.Precipitation events lasting over 24 hours account for about 39%.