摘要
利用常规观测资料、FY-2E卫星观测的TBB资料,对2015年8月19日发生在林芝地区的一次暴雨过程进行天气分析,并利用中尺度数值模式WRF的模拟结果分析此次暴雨过程中尺度系统的结构特征。结果表明,此次暴雨过程发生在高原低涡切变的环流形势下,伴随辐合线发展的线状对流系统是此次暴雨发生的主要原因。WRF模式可较好地模拟出暴雨过程的环流形势和降水的落区、量级。西南风引导的暖湿气流为暴雨的发生、发展提供充沛的水汽条件;对中尺度结构的分析表明,低层辐合、高层辐散的结构以及在降水区存在的正涡度伴随强烈的上升运动为此次暴雨过程提供了有利的动力条件,假相当位温的分布能够为暴雨提供有利的热力条件,垂直螺旋度低层正中心的配置反映出大气的不稳定分布,有利于中尺度对流系统的发展与维持。
Synoptic analyses on a rainstorm event which occurred in Nyingchi area on August 19, 2015 were conducted using conventional observations and TBB satellite data,and then output of mesoscale model WRF was used to analyze the structural characteristics of the mesoscale system.The results indicates that the rainstorm process formed in the shear line and low vortex over the Tibetan Plateau,mesoscale convective system developed with convergence line and the development of the linear convective system which is the main reason for the rainstorm. Simulated precipitation as well as largescale pattern was quiet well by mesoscale model WRF. Southwest flow provides abundant vapor conditions for the rainstorm and low -level convergence,high -level divergence as well as strong upward motion provide dynamic conditions for the occurrence and development of this rainstorm process,The distribution of pseudo-equivalent temperature can provide favorable thermal conditions for rainstorm.Distribution of vertical helicity can reflect atmospheric instability,which provides favorable condition for the development of the mesoscale convective system.
作者
田畅
隆霄
韩子霏
TIAN Chang;LONG Xiao;HAN Zifei(College of Atmospheric Sciences,Lanzhou University,Lanzhou 73000,China)
出处
《沙漠与绿洲气象》
2019年第2期13-21,共9页
Desert and Oasis Meteorology
基金
国家自然科学基金(41375033)资助
关键词
青藏高原
暴雨
数值模拟
对流
Tibetan Plateau
rainstorm
numerical simulation
convection
