利用NECP的FNL再分析资料,对1522号强台风“彩虹”在近海急剧增强的特征及机理进行分析.结果表明:“彩虹”强度变化与南亚高压、副热带高压的环流配置存在密切的联系,南亚高压由西部型调整为东部型,并且在我国东部沿海台风中心上方形成一个很强的高压中心,有利于高空辐散的增强,同时500 hPa副热带高压西伸北抬海上水汽输送加强,为“彩虹”的发展提供有利的环境条件;介于-4～4 m/s弱的200 hPa和850hPa高低层环境风垂直切变是“彩虹”急剧增强的必要条件,并且“彩虹”强度的急剧变化与低层弱的垂直风切变存在显著的滞后相关;台风的暖心结构在台风急剧增强的过程中迅速加强,暖心结构维持较好也是其强度维持的重要因素之一.%Most tropical cyclones weaken or their intensity remains unchanged over the offshore of China,while some tropical cyclones intensify rapidly.Based on the FNL reanalysis data from NCEP,the characteristics and mechanisms of a significant enhancement in the coastal waters of the strong typhoon Mujigae are analyzed.The results show that the rapid intensify of Mujigae has a close relation with the large scale atmospheric circulation.During the rapid intensification stage,the South Asia high changes from western pattem to eastern pattern with a strong anticyclone center over the center of the typhoon in the eastem China coastal waters,which is in favor of the enhancement of the divergence at upper level.The enhanced vapor transport is also helpful to the westward and northward extension of the subtropical high.The critical vertical shear between 850 and 200 hPa with magnitude of-4～4 m/s is an essential condition of typhoon rapid intensification over the offshore of China.There appears to be a time lag between the change of low level (850～ 1000 hPa) vertical wind shear and the typhoon intensity rapid change.The sharp intensify of the Mujigae is accompanied with the warm core of the typhoon strengthened rapidly.The warm core maintains a better structure which could be an important factor to maintain its strength.
展开▼
