一次东移西北涡暴雨过程的诊断分析  

Diagnostic analysis of a heavy rainfall event due to an eastward-moving northwest vortex

作　　者：侯书勋 张婉莹[1] 陈震[1] 王冠[1] 袁媛 HOU Shu-xun;ZHANG Wan-ying;CHEN Zhen;WANG Guan;YUAN Yuan(Tangshan Meteorological Service,Tangshan 063000,China;Nanjing Meteorological Service,Nanjing 210000,China)

机构地区：[1]唐山市气象局,河北唐山063000 [2]南京市气象局,江苏南京210000

出　　处：《气象与环境学报》2018年第5期9-15,共7页Journal of Meteorology and Environment

基　　金：河北省科技计划项目(15275417);河北省气象局面上项目(17ky17)共同资助

摘　　要：利用常规高空、地面观测资料以及NECP的1°×1°FNL资料,对2016年8月17—18日西北涡东移发展造成的暴雨过程进行诊断分析,探讨了西北涡东移演变及其引发强降水的物理机制。结果表明:西北涡是造成此次暴雨的直接影响系统。西北涡在东移过程中强度先后有两次增大衰减,两次峰值对应东西两个强降水中心。西北涡第一次增强的重要原因是台风"电母"远距离输送水汽与能量。第二次增强的原因为西北涡从内蒙古高原移至华北平原时等熵面倾斜,垂直风切变或湿斜压增加导致倾斜涡度发展。研究发现,纬向型西北涡由燕山山脉南下发展垂直涡度增强,一定条件下可以在河北地区诱发大暴雨。Based on the conventional high-level and surface observational data and the FNL data with spatial resolution of 1°×1° from the National Centers for Environmental Prediction/National Center （NECP）,the heavy rainfall event caused by an eastward-moving northwest vortex on August 17-18,2016 was diagnostically analyzed.The evolution of the northwest vortex and the physical mechanism of this heavy rainfall event were discussed in this study.The results showed that the northwest vortex is the direct system influencing on the heavy rainfall event.The intensity of this northwest vortex increases and decreases twice during its eastward movement,and the two peaks correspond to two heavy rainfall centers.The long-range transport of water vapor and energy from the typhoon ＂Dianmu＂ is an important reason for the enhancement of northwest vortex for the initial phase,and its second phase enhancement is due to the declination of isentropic surface as the northwest vortex moves from the Inner Mongolia plateau to the North China Plain,which leads to the development of slantwise vorticity after the increase in vertical wind shear and wet baroclinic zone.The low-level vortex shifts down the Yanshan Mountain,which is favorable for the enhancement of vertical vorticity.The zonal northwest vortex can trigger heavy rainfall in Hebei region under specific conditions.

关 键 词：西北涡 增强机制 台风 倾斜涡度发展 

分 类 号：P40[天文地球—大气科学及气象学]