中尺度地形对热带气旋边界层的影响

基于梯度风动量近似理论,考虑气压梯度力、科氏力、湍流摩擦力、离心力和惯性偏差力5力平衡,得到了柱坐标系下具有热带气旋边界层特征的解析解.并着重讨论了三维钟型孤立地形及二维钟型地形对径向速度、垂直水平流场及垂直速度场的影响.对于数值解的再现表明,热带气旋内边界层的运动同时受到湍流摩擦作用与地形作用的共同影响,二维钟型地形比三维钟型孤立地形对于垂直速度场、径向速度场及流场有更明显的影响.而热带气旋中心与地形中心的不重合会产生风场的不对称结构,且会在地形西北侧形成"偶极型"的垂直速度.

The effect of mesoscale mountain in the boundary layer of the tropical cyclone

Based on the gradient-wind momentum approximation（GRMA）,the balance among five forces is established which includes： the pressure-gradient force,the Coriolis force,the frictional force,the centrifugal force,and the inertial deviation.The analytic solutions which describe the characteristics of the tropical cyclone boundary layer are obtained under cylindrical coordinates.The three dimensional bell-shaped mountain and two dimensional bell-shaped mountain are studied principally.The numerical repeting results indicate that,motion in the boundary layer of the tropical cyclone is controlled by the eddy viscosity and mountain simultaneously.Two dimensional bell-shaped mountain has more evident impact on the vertical velocity,radial velocity,and streamlines when compared with three dimensional bell-shaped mountain.The misalignment of the centers of tropical cyclone and mountain leads to the asymmetric structure of the wind-field.The ＂dipolar-structural＂ vertical velocity forms at the north-west side of the mountain.