北京及周边地区冬季降水相态的判别指标研究  

Discrimination Criteria of Winter Precipitation Types in and Around Beijing

作　　者：荆浩 于波 张琳娜 邢楠 符娇兰 戴翼 杜佳 JING Hao;YU Bo;ZHANG Linna;XING Nan;FU Jiaolan;DAI Yi;DU Jia(Beijing Weather Forecast Centre,Beijing 100091;National Meteorological Centre,Beijing 100081)

机构地区：[1]北京市气象台,北京100091 [2]国家气象中心,北京100081

出　　处：《气象》2022年第6期746-759,共14页Meteorological Monthly

基　　金：北京市自然科学基金项目(8192019、8214058);国家重点研发计划(2018YFF0300104);中国气象局创新发展专项(CXFZ2022J013);北京市科技计划项目(Z201100005820002)共同资助。

摘　　要：基于2012—2020年冬季地面观测、探空及多种观测资料,研究北京观象台及邻近的张家口站、乐亭站3个气象站不同降水相态下的垂直温湿结构,建立降水相态的判别指标。从预报角度着眼于成雪和融雪两方面,把云顶温度和0℃层高度作为相态判别的关键要素,分析表明:云顶温度≤-14℃是云中能够产生充足雪花等冰相粒子的重要阈值,是降雪的必要条件,同时0℃层高度≥0.5 km和≤0.1 km分别是雪花完全融化和几乎不融化的阈值;云顶温度在-14~-4℃时,更容易出现雨夹雪或降雨,0℃层高度为0.1 km则是区分雨夹雪和雨的阈值。云顶温度与0℃层高度结合构成的相态判别指标较特定层气温组合构成的指标TS评分显著提高,雪、雨夹雪和雨的TS评分分别为0.93、0.57和0.86,分别提高了0.11,0.39和0.43。研究结果对于冬季降水相态的预报与订正提供了新的参考。The 2012-2020 surface observation and sounding data from Beijing Meteorological Observatory,Zhangjiakou Station and Laoting Station in winter as well as other data are used to establish a set of discrimination criteria for different precipitation types by statistically analyzing vertical temperature and humidity profiles.From forecast perspective,we focus on two key factors of snowflakes forming and melting,and adopt the cloud-top temperature and the 0℃-layer height as new indicators of discrimination criteria for precipitation types.The results show that cloud-top temperature below or equal to-14℃is a key threshold to generate adequate snowflakes or other ice particles in clouds.This is a necessary condition for snowfall.At the same time,the 0℃-layer height higher than or equal to 0.5 km and lower than or equal to0.1 km is a threshold for the snowflakes to hardly melt and completely melt,respectively.Sleet or rain is likely to appear with cloud top-temperature between-14℃and-4℃.The 0℃-layer height at 0.1 km is a threshold of distinguishing sleet from rain.The TS scores of discrimination criteria based on cloud-top temperature and 0℃-layer height in this paper are significantly improved compared with those by using the combination of temperatures at specific layers.The TS scores for snow,sleet and rain reach(improved)0.93(0.11),0.57(0.39)and 0.86(0.43),respectively.The results of this study could provide a new reference for forecast and amendment of winter precipitation type.

关 键 词：降水相态 云顶温度 0℃层高度 探空资料 

分 类 号：P456[天文地球—大气科学及气象学]