台风"山竹"和"天鸽"对云南降水天气影响分析

Precipitation Weather Analysis of Typhoon“Mangkhut”and“Hato”in Yunnan

利用常规观测资料,NCEP1°×1°再分析资料和MJO指数对台风天鸽(201713)和山竹(201822)从MJO背景条件、环流背景和卫星云图等方面对云南降水影响进行对比分析。分析表明:山竹和天鸽均在广东沿海登陆,其登陆位置偏东后西行进入影响云南的关键区Ⅲ,在MJO强背景下云南强降水区域更大,强度更强。500hPa上强盛的带状副热带高压引导台风以西行为主进入云南,700hPa上孟加拉湾至中南半岛一带低压环流与台风低压中心位置纬度差距不大有利于台风低压环流的维持和西移影响云南。台风西行过程中较大的水汽通量、较强的上升运动以及登陆时密实的低压云团、进入广西后对流云系减弱较慢等都有利于台风降水在云南的维持。

Based on conventional observation data,NCEP 1°×1°reanalysis data and MJO index,the impact of Hato and Mangkhut on precipitation in Yunnan was compared and analyzed from MJO background conditions,circulation background,satellite cloud image,etc.The results show that both Hato and Mangkhut landed on the coast of Guangdong.The area of heavy precipitation in Yunnan was larger and stronger under the strong MJO background after landing position entered into the key area ofⅢaffecting Yunnan from east by west.The strong linear subtropical high resistance on 500hPa guided the typhoon to the west,and then into Yunnan.The latitude of low pressure circulation from the Bay of Bengal to the Indochina region was not much different from the latitude of the center position of the typhoon,it was beneficial to the maintenance of the typhoon low pressure circulation affecting Yunnan.The process of typhoon westbound with the strong water vapor flux and rising movement,the dense low-pressure cloud system.After the typhoon entered Guangxi,the weakening of the convective cloud system was beneficial to the maintenance of its precipitation.