台风移动规律的研究 Ⅱ.小地形与边界层的动力作用

从支配台风中心移动的基本方程出发，着重分析了小地形（地形高度与台风系统的的垂直厚度相双为小量）的抬升作用和边界层的摩擦作用对台风移动影响的定性特征。结果表明，较高地势对台风有“吸收”作用；边界层摩擦辐合引起的艾克曼抽吸有利于台风产生沿局地流场引导速度方向的加速度。

A STUDY ON TYPHOON MOVEMENT II. DYNAMICAL ROLE OF SMALL TOPOGRAPHY AND THE BOUNDARY LAYER

The dynamic effects of small topography (in the sense of the characteristic height of the topography as compared with the vertical thickness of the system of motion) and the Ekman pumping caused by the frictional convergence in the boundary layer on the motion of a typhoon have been qualitatively discussed in this part based on the governing equation of typhoon motion derived in part I of this paper. The results show that a topographical ridge tends to attract the typhoon approaching it and this explains at least partially the phenomenon that the typhoons over the western Pacific tend to accelerate just before their making landfall over the coastal areas.It is also shown that the Ekman pumping at the top of the boundary layer favors the typhoon acceleration along the local steering current.