A Diagnostic Study of the Asymmetric Distribution of Rainfall during the Landfall of Typhoon Haitang(2005)  

作　　者：YUE Caijun GAO Shouting LIU Lu LI Xiaofan 

机构地区：[1]Shanghai Typhoon Institute,China Meteorological Administration [2]Institute of Atmospheric Physics,Chinese Academy of Sciences [3]University of Chinese Academy of Sciences [4]Department of Earth Sciences,Zhejiang University

出　　处：《Advances in Atmospheric Sciences》2015年第10期1419-1430,共12页大气科学进展（英文版）

基　　金：supported by Public Sector (Meteorology) Research of China (Grant Nos.GYHY 201306012 and GYHY201506007);the National Natural Science Foundation of China (Grant Nos.40875025,41175050,41475039 and 41475041);the Shanghai Natural Science Foundation of China (Grant No.08ZR1422900)

摘　　要：The precipitation during landfall of typhoon Haitang （2005） showed asymmetric structures （left side/right side of the track）. Analysis of Weather Research and Forecasting model simulation data showed that rainfall on the right side was more than 15 times stronger than on the left side. The causes were analyzed by focusing on comparing the water vapor flux, stability and upward motion between the two sides. The major results were as follows： （1） Relative humidity on both sides was over 80%, whereas the convergence of water vapor flux in the lower troposphere was about 10 times larger on the right side than on the left side. （2） Both sides featured conditional symmetric instability [MPV （moist potential vorticity） 〈0], but the right side was more unstable than the left side. （3） Strong （weak） upward motion occurred throughout the troposphere on the right （left） side. The Q vector diagnosis suggested that large-scale and mesoscale forcing accounted for the difference in vertical velocity. Orographic lift and surface friction forced the development of the asymmetric precipitation pattern. On the right side, strong upward motion from the forcing of different scale weather systems and topography caused a substantial release of unstable energy and the transportation of water vapor from the lower to the upper troposphere, which produced torrential rainfall. However, the above conditions on the left side were all much weaker, which led to weaker rainfall. This may have been the cause of the asymmetric distribution of rainfall during the landfall of typhoon Haitang.The precipitation during landfall of typhoon Haitang （2005） showed asymmetric structures （left side/right side of the track）. Analysis of Weather Research and Forecasting model simulation data showed that rainfall on the right side was more than 15 times stronger than on the left side. The causes were analyzed by focusing on comparing the water vapor flux, stability and upward motion between the two sides. The major results were as follows： （1） Relative humidity on both sides was over 80%, whereas the convergence of water vapor flux in the lower troposphere was about 10 times larger on the right side than on the left side. （2） Both sides featured conditional symmetric instability [MPV （moist potential vorticity） 〈0], but the right side was more unstable than the left side. （3） Strong （weak） upward motion occurred throughout the troposphere on the right （left） side. The Q vector diagnosis suggested that large-scale and mesoscale forcing accounted for the difference in vertical velocity. Orographic lift and surface friction forced the development of the asymmetric precipitation pattern. On the right side, strong upward motion from the forcing of different scale weather systems and topography caused a substantial release of unstable energy and the transportation of water vapor from the lower to the upper troposphere, which produced torrential rainfall. However, the above conditions on the left side were all much weaker, which led to weaker rainfall. This may have been the cause of the asymmetric distribution of rainfall during the landfall of typhoon Haitang.

关 键 词：LANDFALL TYPHOON RAINFALL asymmetric distribution water vapor atmospheric stability vertical motion 

分 类 号：P458.124[天文地球—大气科学及气象学]