我国中东部地区夏季中尺度对流系统形成前物理量诊断分析  

Diagnostic analysis of physical quantities for the precursor environment of mesoscale convective system during summer in central-eastern China

作　　者：曾波[1] 谌芸 李泽椿 

机构地区：[1]中国气象局成都高原气象研究所,成都610072 [2]国家气象中心,北京100081

出　　处：《地球物理学报》2015年第1期32-46,共15页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41175048);国家重点基础研究发展计划(973)项目(2012CB417202);行业专项(GYHY201406001和GYHY201206004)共同资助

摘　　要：利用2008—2010年夏季（6—8月）FY-2地球静止卫星红外云图资料识别出我国中东部地区（110°E—124°E,27°N—40°N）共208个中尺度对流系统（mesoscale convective system,MCS）和174个不能增长发展成为MCS的普通雷暴群（widespread convections,WCS）.提取MCS形成前约6h和WCS成熟时（个数最多）的NCEP再分析资料（时间间隔6h,空间分辨率1°×1°）,通过对表征水汽、动力和热力等条件的基本物理量和一些常用衍生物理量采用平均值、标准差等常用统计方法、动态合成和评估方法逐步筛选和分析诊断两种系统环境物理量场,最终从众多物理量中挑选出了能显著区别两种系统的物理量（即MCS形成的关键物理量）,分别为强天气威胁指数、修正的K指数、地面抬升指数、2m比湿和0-3km垂直风切变,希望对预报我国中东部地区MCS发生与否提供一定的科学依据.Mesoscale convective systems（MCSs）can devastate property and possessions by generating heavy rainfall and severe weather during summer over central-eastern China.If the critical parameters in determining whether concentrated convection would undergo upscale growth into an MCS are found,then the damages produced by severe weather can be prevented and reduced in central-eastern China.The NCEP data were used to compare the environments prior to MCS development with the environments of widespread convections（WCS）that did not undergo upscale growth and organization into MCS across central-eastern China（110°E—124°E,27°N—40°N）during summer（June—August）of 2008—2010.This analysis is based on the recognition result of 208 MCSs and 174 WCS.One method used in this analysis involved taking a single value of a given field for each case at a specific point.For MCSs the NCEP analysis data（time resolution every 6 h,spatial resolution 1°×1°）were extracted at 6hprior to development from the location of centroid of the MCS at initiation,which were taken at the time of the maximum number of convective cells from the approximate center of the group of thunderstorms for WCS.A statistical analysis of mean and standard deviations of the data was made once all of the point-value data were compared for the different conditions.A14°×10°movable grid centered on each case for the precursor environments of MCS and WCS was used to create composites of numerous parameters.An objective method of evaluation（POD,FAR,HSS,TS and BS）including making a dichotomous forecast was also implemented to test the skill and accuracy of the various parameters in forecasting MCSs.The precursor environments of hundreds of MCSs and instances of WCS were examined to gain insights into environmental conditions that support a concentrated group of thunderstorms into an MCS.Significant differences were found during these physical quantities between MCSs and WCS：（1）A statistical analysis of point-value data was performed t

关 键 词：MCS 统计 动态合成 评估分析 

分 类 号：P43[天文地球—大气科学及气象学]