渭河流域一次对流性暴雨过程分析  

Analysis of a Convective Rainstorm Process in Weihe River Valley

作　　者：王旭仙[1] 武麦凤[1] 许伟峰[1] 肖湘卉[1] 张丽娟[1] 

机构地区：[1]陕西省渭南市气象局,渭南714000

出　　处：《暴雨灾害》2011年第3期241-246,共6页Torrential Rain and Disasters

基　　金：陕西省气象局2011年度科技创新基金项目"卫星云图在渭河流域短时暴雨预报中的应用"(2011M-10)

摘　　要：使用常规观测资料、FY-2E红外卫星云图及其反演产品TBB、多普勒雷达资料、地面加密自动站资料,分析渭河流域一次对流性暴雨天气过程。结果表明:在西风槽东南移及副热带高压西伸北抬背景下,由地面中尺度辐合线触发形成的1个MαCS和3个MβCS是这次过程的直接影响系统;中高层前倾槽结构和低层较强垂直风切变有利强对流不稳定层结形成并发展,导致对流性暴雨;强降水出现在中尺度对流云团发展强盛到成熟阶段,强降水落区位于TBB低值中心附近或中心到后部TBB梯度最大处,MαCS和MαCS对应的强降水均与雷达径向速度图上"逆风区"对应;单站强降水时段与低TBB值对应较好,雨强与TBB值变化趋势相反,即TBB降低时雨强增大、TBB猛升时雨强减小,TBB≤-75℃时雨强>20 mm.h-1;渭河流域特殊地形对MCS发展起促进和加强作用。Analysis of a convective rainstorm process in Weihe river valley was performed with the data of routine aerological sounding,FY-2E satellite images and TBB data,Doppler-Radar data and the intensive observations of automatic weather station.The results show that one MαCS and three MβCS that triggered by surface mesoscale convergence lines are the synoptic systems to influence directly the occurrence of the process in the background of westerly trough moving southeastwards and Western Pacific subtropical high moving westwards and northwards.Forward-tilting trough structure in mid-and-upper level and strong vertical wind shear in low-level is propitious to the formation and development of unstable stratification of severe convective,which lead to the convective rainstorm.Severe precipitation emerges at developing and mature stages of mesoscale convective cloud clusters,and distribution of severe precipitation locates in the dense areas of TBB gradient.The severe precipitations with MαCS and MαCS are all corresponding with counter-wind zones in the Radar radial velocity field.The severe precipitation at single station is better corresponding with the low TBB,and the rainfall intensity is contrary to the trend of TBB,that is when TBB has a decrease trend,the rainfall intensity increases,and when TBB has a severe increase trend,the rainfall intensity decreases,and When TBB≤-75 ℃,the rainfall intensity is over 20 mm·h-1.In addition,the special terrain of Weihe River valley has promotion to develop MCS.

关 键 词：对流性暴雨 云图特征 MCS 渭河流域 

分 类 号：P458.121.1[天文地球—大气科学及气象学]