中文摘要：

利用美国WRF（Weather Research Forecast）模式对＂海棠＂台风（0505）登陆前后的雨带变化进行分析和模拟试验。结果显示：台风登陆前后其雨带会产生断裂,这种现象可发生在陆地和海上,使非对称降水更加明显。分析得出雨带断裂不仅与地形有关,而且与高层台风环流和中纬度系统的相互作用有关：台风登陆前后,200hPa南亚高压和台风外围的辐散气流结合形成在台风西北方向的弱倒槽,台风中心西侧及西北侧的中低层辐散流场稳定维持,使高层气旋性流场加强,与气旋性流场相伴的正涡度一部分随气流逆时针旋转,并逐步平流至台风中心附近的正涡度区形成一个沿22～25°N的正涡度输送带并延伸至台风中心东部,而中心东部高层的正涡度带中有下沉运动,不利于降水发展而导致雨带断裂是非对称降水的主要原因。高层台风的带状涡度向外围的传播可导致中纬度气旋性环流的进一步加强和正涡度向台风输送的加强,使雨带断裂更加明显。

英文摘要：

Using the WRF（Weather Research Forecast） model, this paper performs analyses and simulating experiments of rainband changes around the time when the 2005 typhoon Haitang（0505） landed on China. The results have the following indications： （1） Around the time of landfall such breaking may occur over both land and sea, thereby leading to more distinct asymmetric precipitation; the breaking relates not only to topography but to interactions between the typhoon and midlatitude systems at higher levels. （2） Around the time of the landfall the 200 hPa South-Asian high divergent flows combine with the divergent air outside the typhoon to form a weak inverted trough in the northwest part of the storm. （3） The mid- and low-level divergence fields on the west and northwest side of the typhoon center remain stable, thus intensifying the high-level cyclonic flows. （3） Part of the positive vorticity associated with the cyclonic flows rotates counterclockwise with the air currents and move in advection into a zone of positive vorticity in the vicinity of the typhoon core, thereby forming a vorticity transfer belt in 22 - 25 °N that extends to the eastern part of the storm. （4） The high-level vorticity band shows subsidence that prevents rainfall from development, resulting in the breaking of rainbands, which is the principal cause of asymmetric precipitation occurrence. The band-shaped vorticity of Haitang at high levels migrating into its outer region cause further amplification of cyclonic circulation in the western part and the transfer of positive vorticity into the typhoon such that more distinct rainband breaking is caused.