“7.20”暴雨过程中分钟级雨量特征分析

利用四川境内加密自动站分钟雨量、风场、温度、本站气压、湿度等资料对2012年7月20~22日四川境内的一次区域性暴雨天气过程的降水持续时间、强降水时段平均降水率和降水变率、强降水开始1小时特征、强降水中心雨量变化与本站气压、温度、湿度的对应关系进行了统计分析,初步探讨了不同时段的强降水分钟级雨量的时空分布特征。结果表明:针对本次过程而言,第一个强降水时段内发生的强降水具有降水率大,持续时间短,突变性强的特点,预报难度较大,而对于第二强降水时段内降水持续时间较长,降水率也较高,结合地面自动站的风场、温度、湿度和本站气压的资料能有一定的预报提前量。 

Minute-level Precipitation Characteristics of a Heavy Rain on July 20, 2012 in Sichuan

The minute-level precipitation characteristics of a heavy rain during 20~18 July 2012 isusing by using statistical method and data from expanded automatic weather stations,including minute and hour level rainfall,wind,temperature,atmospheric pressure,relative humidity and etc..The result showed that this precipitation process contains two stages.The characteristics of strong precipitation in the first stage included high precipitation rate,shorter precipitation duration and higher precipitation mutability,which may be the reasons that this kind of strong precipitation is hard to forecast exactly.In the second stage,the strong precipitation possesses longer precipitation duration,and higher precipitation rate.Besides,the study also shows that synthesizing the automatic observing stations' wind data,temperature data and atmospheric pressure data can provide a certain time interval for prediction of strong precipitation.