池州地区冬季固态降水相态判别指标研究  

Study on Phase Discrimination Index of Winter Solid Precipitation in Chizhou,Anhui Province

作　　者：孙卉 吴语燕 宣普 蔡茶花 王惠 张明明 Sun Hui;Wu Yuyan;Xuan Pu;Cai Chahua;Wang Hui;Zhang Mingming(Chizhou Meteorological Office of Anhui Province,Chizhou 247100,China;Qingyang Weather Station of Anhui Province,Qingyang 242800,China)

机构地区：[1]池州市气象局,安徽池州247100 [2]青阳县气象局,安徽青阳242800

出　　处：《气象与环境科学》2024年第2期9-15,共7页Meteorological and Environmental Sciences

基　　金：2020年安徽省气象局预报员专项项目(kY202008)。

摘　　要：采用池州站地面气象观测资料,遴选出20032019年冬半年固态降水过程。根据T-mode主成分分析(TPCA)法,将冬半年环流形势分为一槽一脊型(Ⅰ型)、纬向波动型(Ⅱ型)和两槽一脊型(Ⅲ型)。其中,Ⅰ型的占比最多(45.2%),Ⅱ型的次之(28.8%),Ⅲ型的占比最少(25.9%)。池州地区固态降水主要受中路冷空气影响。统计固态降水过程中的4种降水相态:雨、雨夹雪、雪、直接降雪,共得到降雨样本43个,雨夹雪样本54个,降雪样本39个,直接降雪样本52个,分别统计其出现时间;再根据箱线图法,使用ERA5资料中的高空各层温度、0℃高度、厚度层结,以及气象观测站的地面温度等进行分析,得出判别指标,并进行检验。结果表明:t_(1000hPa)<0℃、t_(925hPa)<-3℃、t_(850hPa)<-3℃且t_(2m)<0.8℃时会出现雨转雪;t_(1000hPa)<-1.3℃和t_(850hPa)<-5.7℃时为直接降雪;中低层普遍存在逆温;0℃层高度<260 m时基本为纯雪,0℃层高度>266 m为雨;H_(700-850hPa)雨雪转换临界值为154 dagpm,153 dagpm以下为直接降雪,H_(850-1000hPa)<129 dagpm为纯雪,128 dagpm以下时为直接降雪;雨夹雪判别指标不明,其中地面气温效果相对较好。Based on the surface meteorological observation data from Chizhou station,the solid precipitation processes in the winter half year of 20032019 are selected.According to T-mode principal component analysis(TPCA),the circulation situation in the winter half year is divided into three types:the one trough and one ridge type(TypeⅠ),the zonal fluctuation type(TypeⅡ)and the two troughs and one ridge type(TypeⅢ).Type I accounts for the largest proportion(45.2%),TypeⅡtakes the second place(28.8%),and TypeⅢhas the lowest percentage(25.9%).The solid precipitation in Chizhou region is mainly affected by the mid-way cold air.Four kinds of precipitation phases in the process of solid precipitation are summed up:rain,sleet,snow and direct snowfall.The gained sample numbers are 43 for rainfall,54 for sleet,39 for snowfall and 52 for direct snowfall,and their occurrence times are counted respectively.Then,according to the box-line plot method,the upper-air temperature of different layers,0℃height,thickness stratification in ERA5 data and the ground temperature at the meteorological stations are used for analysis,and the discrimination indexes are obtained and tested.The results show that when t_(1000 hPa)<0℃,t925 hPa<-3℃,t_(850 hPa)<-3℃and t_(2m)<0.8℃,rainfall tends to turn to snowfall;when t_(1000 hPa)<-1.3℃and t850 hPa<-5.7℃,direct snowfall will occur.Temperature inversion generally exists in the middle and low layers.When 0℃layer height is<260 m(>266 m),it is basically pure snow(rain).The critical value of height for the conversion of rain and snow is 154 dagpm at H_(700-850 hPa),for direct snowfall is below 153 dagpm,for pure snow at H_(850-1000 hPa) is below 129 dagpm and for direct snowfall is below 128 dagpm.The discrimination index of sleet is not clear,but the effect of ground temperature is relatively good.

关 键 词：降水相态 T-mode主成分分析 判别指标 箱线图 厚度层结 

分 类 号：P466[天文地球—大气科学及气象学]