摘要
在台风环流边缘区域给出不稳定模态的扰动四波分布作为初始场，用准地转正压模式实施四组数值积分，研究了边缘区域扰动演变及其对台风非对称结构及外区流型的影响。结果表明：线性平流对于外缘区域扰动的发展起主要作用。尸项导致一个气旋一反气旋涡旋对和非对称结构的形成。非线性平流则使外缘区域较小尺度的涡旋破碎，形成更小尺度的涡旋。在线性平流、β项和非线性平流的共同作用下，台风结构与外区形成象螺旋云系的分布。外缘区域扰动引起的结构变化，进而能影响到台风的移动路径。
This paper investigate the evolution of vortices of smaller scales in the edge region and their effects on the structure of tropical cyclones using a quasi-geostrophic barotropic model and four numerical experiments with the integration time longer than 42 model hours. The initial conditions are the most unstable eigenmodes with the azimuthal wavenumber of four in the corresponding linear stability analyses which are characterized by smaller scale vortices. Results show that the linear advection is responsible for the growth and extension of the smaller scale vortices in the edge region and that the evolving beta -term can result in the formation of a cyclonic-anticyclonic vortex pair in the inner region and the asymmetric structure of the tropical cyclone. It is shown that the evolving nonlinear advection is fundamental to the bursting of the smaller scale vortices into fragments and formation of all the more smaller ones. Regarding the combined effects of the linear and nonlinear and beta-term, the asymmetric structure of the tropical cyclone and the vortex filaments exhibiting in the edge region are more similar to the observational phenomenon in the real atmosphere.
出处
《大气科学》
CSCD
北大核心
1994年第5期513-519,共7页
Chinese Journal of Atmospheric Sciences
基金
国家重大科技攻关项目
关键词
涡旋
台风
抗动演变
边缘区域
smaller vortices
tropical cyclone
asymmetric structure
numerical experiments.
