2020年3月28日沿江和苏南突发降雪多源监测特征及成因分析  

Multi-Source Monitoring Characteristics and Causes of Abrupt Snowfall in Southern Jiangsu on 28 March 2020

作　　者：刘梅[1,2] 俞剑蔚 蒋义芳[1,2] 喜度 李聪[3] LIU Mei;YU Jianwei;JIANG Yifang;XI Du;LI Cong(Jiangsu Meteorological Observatory,Nanjing 210008;Key Laboratory of Transportation Meteorology,CMA,Nanjing 210009;Nanjing Meteorological Bureau,Nanjing 210019)

机构地区：[1]江苏省气象台,南京210008 [2]中国气象局交通气象重点开放实验室,南京210009 [3]南京市气象局,南京210019

出　　处：《气象》2021年第10期1169-1181,共13页Meteorological Monthly

基　　金：中国气象局预报员专项(CMAYBY2019-040)资助。

摘　　要：利用自动气象站、双偏振雷达、微波辐射计和NCEP再分析资料,结合中尺度WRF模式模拟结果,分析了2020年3月28日江苏的沿江和苏南地区突发降雪前后多源监测资料相关特征及温度突降成因。研究表明:本次突发降雪的气温突降时间、区域变化与较强降水开始时间、移动方向一致。微波辐射计反演产品中0℃层高度下降和液态水含量的增加可作为地面气温和降水相态转换的临近判据,地面气温的下降滞后于1.5~3.0 km高度气温的下降(约2~3 h)。双偏振雷达反射率、相关系数和分类产品对雨雪转换和雪区扩展方向判断具有显著特征,0℃层亮带区域、形态变化与低层降温区域、移动方向一致,相关系数中不同相态粒子的非对称性特征和形态变化反映出融化层高度、厚度和移动方向变化,混合相态层不对称特征和分类产品湿雪监测信号早于降雪1~2 h。诊断分析发现冰晶及雪花下沉过程的融化潜热作用和穿过干区的蒸发吸热对低层气温短时迅速下降具有一定正贡献。温度下降呈现自上而下、自西向东的时空变化特点,850~700 hPa高度最先出现下降,近地面气温下降约滞后2 h。研究表明,多源监测资料可为雨雪转换过程提供较好的决策支撑,尤其是在短时临近时效内。The characteristics of multi-source monitoring data and the causes of sudden temperature decline before and after the abrupt snowfall in southern Jiangsu Province on 28 March 2020,are investigated with the data of automatic meteorological station,dual polarization radar,microwave radiometer,NCEP reanalysis data and simulation results of mesoscale model WRF.The research shows that the time and area changes of temperature drop are consistent with the beginning time and moving direction of heavy precipitation in this sudden snowfall.The 0℃layer height decline and the increase of liquid water content inversed by microwave radiometer can be used as the approach criterion to judge the surface temperature and precipitation phase transition.The time of ground temperature decrease lags behind the temperature drop in the 1-3 km height for about 2-3 hours.The radar reflectivity factor,the correlation coefficient and classified products of dual polarization radar products have obvious characteristics in the judgment of rain-snow conversion and snow expansion direction during this snowfall.The light zone and shape change of the 0℃layer are consistent with the cooling zone and movement direction of the lower layer.In the correlation coefficients,the asymmetrical characteristic regions and morphological changes of different phase particles reflect the changes in height,thickness and movement direction of the melting layer.Asymmetric characteristics of mixed phase layer and wet snow monitoring signals of classified products appear 1-2 hours earlier than snowfall.The diagnostic analysis shows that the latent heat of melting during the subsidence of ice crystals and snowflakes and the latent heat of evaporation through the dry area have a positive contribution to the short and rapid decrease of temperature in the lower layer.The temperature change presents the spatio-temporal evolution characteristics from above to below and from west to east.The earliest temperature decline occurs at the height of 850-700 hPa.The near-surface

关 键 词：突发降雪 多源监测资料 变化特征 成因分析 

分 类 号：P412[天文地球—大气科学及气象学] P458