台风“达维”不对称结构特征分析

利用地面加密观测资料、FY-2E卫星TBB和水汽图像资料、NCEP1°×1°再分析资料综合分析了2012 年第10 号台风“达维”的不对称结构特征及成因。结果表明：台风“达维”登陆后在云系结构、降水落区、高低层风场等都表现出不对称分布，其中暴雨主要分布在台风中心北到东北侧；通过FY-2E水汽图像分析清晰地揭示了这种不对称结构的演变，台风西侧干下沉暗区切断了西南侧水汽输送，使得台风中心西侧和南侧对流云系减弱消失，而东南侧一直存在一水汽羽伸入台风环流为其提供水汽和能量。同时，强高空辐散、弱垂直风切变以及明显的上升运动，有利于台风“达维”北到东北侧对流云系的发展维持，引发强降水；高空槽带来的冷空气侵入台风环流内部，破坏了它的暖心结构，使得台风“达维”在渤海海面填塞消失。

Analysis of the asymmetric structure of typhoon Damrey

Based on the surface intensive observed meteorological data,the TBB data from FY-2E satellite and the NCEP 1°×1° reanalysis data,the characteristics of the asymmetric structure of the typhoon Damrey（code 1210） and its forming reason were analyzed.The results indicate that the cloud system structure,precipitation falling area and upper and lower wind fields for the typhoon Damrey are all asymmetric after landfall.The heavy rainstorm mainly appears in the northern and northeastern sides of the center of typhoon Damrey.The evolution of the asym-metric structure could be found obviously by the FY-2 E water vapor images.The dark area located in the western side of typhoon cuts off the southwestern transfer of water vapor,which makes advective cloudsystem in the west-ern and southern sides of typhoon center weakened and disappeared,while water vapor plume from the southeast goes into typhoon circulation and provides water vapor and energy for typhoon.At the same time,strong upper di-vergence,weakly vertical wind shear and evident upward movement are all favorable for enhancement and mainte-nance of advective cloudsystem to the northeastern side of the typhoon Damrey,which could trigger torrential rain. Cold air brought by upper trough intrudes into inside of typhoon and destroys its warm-core structure,which makes typhoon Damrey disappear on the Bohai Sea.