热带气旋碧丽斯(2000)发生的数值模拟:非对称流的发展及转换  

The Numerical Simulation of the Genesis of Tropical Cyclone Bilis (2000): The Evolution and Transformation of Asymmetric Momentum

作　　者：徐亚梅[1] 伍荣生[2] 

机构地区：[1]浙江大学地球科学系,杭州310027 [2]南京大学大气科学系,南京210093

出　　处：《大气科学》2005年第1期79-90,共12页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金重点项目 40 3330 2 5;我国登陆台风灾害的监测及预报技术研究 (2 0 0 1PIA 2 0 0 2 6)

摘　　要：采用NCAR PSU研制的非静力双向嵌套的仔尺度模式MM5 ,模拟了热带气旋碧丽斯 (2 0 0 0 )从热带弱低压发展为热带风暴及台风的过程。分析表明非对称流在低层发展并通过涡动通量项向对称流转换 ,使得热带弱低压快速发展达到热带风暴强度。进一步的分析表明 :涡动通量项不仅依赖于非对称流的强度 ,还取决于非对称流型。当非对称流场为气旋式流入或反气旋式流出时 ,非对称动量向对称动量转换 ,非对称流减弱 ,轴对称流加强 ;反之 ,当非对称流场为反气旋式流入或气旋式流出时 ,动量由对称流向非对称流转换。The evolution of tropical cyclone Bilis (2000) from a very weak tropical depression into tropical storm and typhoon is simulated using the PSU/NCAR nonhydrostatic, two-way interactive, nested grid mesoscale model MM5. It is found that the evolution of asymmetric momentum in the low level and its transformation to symmetric momentum play an important role in the genesis of Bilis. Eddy flux is the exchange term between asymmetric and symmetric momentum. Further analysis shows that the eddy flux is not only associated with the quantity of asymmetric momentum, but also depends on the streamline pattern. If the pattern is cyclonic inflow or anticyclonic outflow, the exchange of the asymmetric to symmetric momentum causes the decrease of asymmetric flow and increase of symmetric flow. Otherwise, there is momentum transport from asymmetric to symmetric flow with pattern of cyclonic outflow or anticyclonic inflow.

关 键 词：热带气旋 热带风暴 NCAR 非静力 MM5 台风 通量 非对称 反气旋 动量 

分 类 号：P444[天文地球—大气科学及气象学] P457.8