基于多源观测资料对湖南怀化一次雨雪天气降水相态特征的分析  

Analysis of Precipitation Phase Characteristics of One Rain-snow Process in Huaihua,Hunan Province,Based on Multi-source Observation Data

作　　者：奚世军 刘恩弘 彭艳青[1] 李争凯 陈红专[1] 石伟 XI Shijun;LIU Enhong;PENG Yanqing;LI Zhengkai;CHEN Hongzhuan;SHI Wei(Huaihua Meteorological Office of Hunan Province,Huaihua 418000,China)

机构地区：[1]湖南省怀化市气象局,湖南怀化418000

出　　处：《山地气象学报》2024年第2期7-16,共10页Journal of Mountain Meteorology

基　　金：湖南省气象局2023年创新发展专项(青年专项)(CXFZ2022-QNZX08);怀化市市局2023年重点课题(HHQX23A003)。

摘　　要：【目的】为了解湖南怀化雨雪天气降水相态演变特征。【方法】选取ERA5资料、微波辐射计和SA双偏振多普勒雷达等多源观测资料作为基础数据,采用常规统计、环流背景、相关分析等方法,对2022年12月27—28日湖南怀化地区一次雨雪天气的降水相态演变特征进行分析。【结果】(1)中高纬地区在中层槽的引导下冷空气南下,中低纬地区在南支槽的引导下西南气流东移,致使冷空气与暖湿气流交汇,降水相态发生变化。过程前低层切变线南压、低空西南急流发展,低层系统处于暖平流中,且地面温度较高,降水相态为雨。28日20时后冷平流快速发展,地面迅速降温,形成“冷垫”,致使降水相态转为雨夹雪。后期受南下强冷空气影响,导致降水相态转为雪。(2)散度和垂直速度的分布说明,降雪阶段的动力条件来源于低层,降雨时段的动力条件来源于高层。(3)SA双偏振多普勒雷达的偏振量分析结果表明,在较大的水平反射率(20~35 dBz)区域,其差分反射率相对较小(约0.8~1.6 dBz之间),差分位移率也相对较小(约-1.2~0.6之间),相关系数>0.88。微波辐射计反演的0℃线可以作为降雪的重要判据,其液态水含量在降雨时含量较高,水汽浓度在降雪时显著下降,可以准确判断降雪的具体时间。【结论】微波辐射计和双偏振雷达的组合应用可以作为怀化地区对降水相态转换临界预报的重要地基观测设备。In order to explore the application of multi-source data in the phase prediction of rain-snow,based on the ERA5 reanalysis data,microwave radiometer and SA dual-polarization Doppler radar observation data,we analyze the precipitation phase characteristics of a rain-snow weather process in Huaihua region of Hunan Province in December 27—28,2022,by using the methods of conventional statistics,circulation background analysis,correlation analysis,etc..The results show that:(1)The cold air moved southward under the guidance of the mid-level trough in the mid-high latitudes,and the southwest airflow moved eastward with the south branch trough in the mid-low latitudes.This led to in the intersection of the cold air and the warm and humid air,changing the precipitation phase.Before the rain-snow process,the low-level shear line moved southward and the low-level southwest jet developed.The low-level system was in the warm advection,and the surface temperature was high,thus the precipitation phase was rain.After 20∶00 on the 28th,the cold advection developed rapidly,cooling the ground rapidly,and a“cold pad”was formed,causing the precipitation phase to turn into sleet.Later,due to the influence of strong cold air from the south,the precipitation phase changed to snow.(2)Through the dynamic diagnosis of divergence and vertical velocity,it is found that the dynamic forcing during the rainfall period was mainly located in the upper layer,while during the snowfall period it was mainly located in the lower layer.(3)The polarization analysis results of the SA dual-polarization Doppler radar show that the differential reflectivity in the larger horizontal reflectivity zone of 20~35 dBz is smaller,being about 0.8~1.6 dBz,and the differential displacement rate is also relatively small,ranging from-1.2 to 0.6,and the correlation coefficient exceeds 0.88.The 0℃line retrieved by microwave radiometer can be used as an important criterion for snowfall.The liquid water content is high during rainfall,and the water vapor concent

关 键 词：微波辐射计 常规探空 降雪过程 气象要素 双偏振雷达 

分 类 号：P458.122[天文地球—大气科学及气象学]