贵州低温阴雨指标构建及适用性分析

Index Construction and Applicability Analysis of Low Temperature and Rainy Process in Guizhou Province

基于贵州省1971—2018年日最低气温、日最高气温、降水量、日照4个要素的气象观测资料,利用概率统计法,得出低温阴雨的量化识别判据,即日最低气温≤4℃,日最高气温≤10℃,日照时数s=0 h,降水量≥0.0 mm(其中,当日照时数s缺测时,云量为十成;当降水量缺测时,相对湿度≥85%)的天气属于低温阴雨事件。在此基础上,根据影响范围、站点重叠、间断日等因素,构建了区域低温阴雨过程指标,即评估区域内连续3 d不少于20%的观测站发生低温阴雨事件,第4 d开始允许间断一天,但日照时数s=0 h的观测站数不少于20%。为了验证这一判别方法的可行性,对近50年贵州低温阴雨天气进行回算检验,结果表明该指标具有合理性和适用性,与贵州天气气候特征相符。

Based on the meteorological observation data of daily minimum temperature,daily maximum temperature,precipitation and sunshine from 1971 to 2018 in Guizhou Province,a quantitative identification metric of low-temperature,overcast and rainy process is proposed by using probability statistics method.The metric stipulates that when the day low≤4℃,day high≤10℃,Sunshine Time s=0 h,precipitation≥0.0 mm(among which,when sunshine time s is absent,the cloud cover is 10%;when precipitation is absent,the relative humidity≥85%),the weather condition is defined to be with a low-temperature overcast rainy event.On this basis,the indexes of regional low-temperature overcast and rainy process are constructed in terms of influence range,station overlap and discontinuous days.That is to say,when evaluating the occurrence of low-temperature,overcast and rainy events at no less than 20%of the observation stations for 3d continuously,an interval of one day is allowed from the 4th day,but the observation stations with hours of Sunshine s=0 h are not less than 20%.At the same time,in order to verify the feasibility of this method,the return calculation test of the low-temperature,overcast and rainy weather in the recent 50 years in Guizhou is carried out.The analysis result shows that this algorithm is reasonable and applicable,according with the weather and climate characteristics of Guizhou.