低纬高原一次短时强降水过程的综合分析  

Comprehensive analysis of a short-time heavy rainfall process over low latitude plateau

作　　者：李华宏[1] 许彦艳[1] 王曼[2] 许迎杰[1] LI Hua-hong;XU Yan-yan;WANG Man;XU Ying-jie(Meteorological Observatory of Yunnan Province,Kunming 650034,China;Yunnan Institute of Meteorology,Kunming 650034,China)

机构地区：[1]云南省气象台,云南昆明650034 [2]云南省气象科学研究所,云南昆明650034

出　　处：《云南大学学报（自然科学版）》2020年第3期515-524,共10页Journal of Yunnan University(Natural Sciences Edition)

基　　金：国家自然科学基金(41805037,41565004).

摘　　要：利用卫星、雷达、地面自动站及闪电定位仪等多种观测资料分析了2017年9月5-6日出现在云南的一次短时强降水天气过程的成因及中尺度对流特征.结果表明:此次过程期间短时强降水天气落区分布呈现自东北向西南逐渐移动趋势,系统性降水特征明显;700 hPa切变线和地面锋面是此次过程的关键影响系统,切变线提供了中低层水汽辐合及对流抬升运动的维持机制,地面锋面则为低层对流抬升运动提供了触发机制;中尺度对流云团的空间尺度和持续时间对短时强降水的分布区域和规模有很好的指示意义,短时强降水主要出现在云顶亮温<-50℃的区域,对流云团空间尺度大、持续时间长,则对应时段的短时强降水分布范围广、频次多.雷达观测有助于短时强降水天气的精细化订正和及时预警,当雷达回波强度达到45 dBz以上并具明显低质心特征、径向速度图上有中尺度辐合配合时,出现短时强降水的可能性较大.The synoptic causes and mesoscale convective characteristics of a short-time heavy rainfall process were analyzed,which occurred in Yunnan Province from 20:00 on September 5 to 20:00 on September 6,2017,based on the observational data of satellites,radars,ground automatic stations and lightning locators.The results show that the distribution of short-time heavy rainfall areas gradually shifted from northeast to southwest,which indicated obvious characteristics of systematic precipitations.The shear line on 700 hPa and the cold front on the ground are the key influencing systems of this case.The shear line provided a mechanism for maintaining water vapor convergence and convective uplift in the middle layer;and the cold front provided a triggering mechanism for the convective uplift in the lower layer.The spatial scale and duration of meso-scale convective cloud clusters well indicated the distribution and scale of short-term heavy rainfall,because the short-time heavy rainfall events mainly occurred in the areas with cloud top brightness temperatures below-50℃.If the convective cloud clusters have a large spatial scale and long duration,the short-time heavy rainfall in corresponding periods will be wide and frequent.Radar observation is helpful for fine forecast correction and early warning of short-time heavy rainfall weather.When the radar echo intensity reaches and exceeds 45 dBz and has obvious low center characteristics with a meso-scale convergence of radial velocity,short-time heavy rainfall will follow in the same area.

关 键 词：冷锋切变 短时强降水 预报指标 低纬高原 

分 类 号：P426.6[天文地球—大气科学及气象学]