“莫兰蒂”台风致灾大风的结构特征及成因

利用多种观测资料分析1614号"莫兰蒂"台风致灾大风的风场结构特征及成因。结果表明:"莫兰蒂"登陆前台风环流内的局地强风呈阶段性波动特征,局地强风相对台风方位角的变化随着台风靠近先顺转后逆转;基于台风风压关系的分析表明"莫兰蒂"强度估计与实测吻合;台风登陆后受地形摩擦影响,台风左侧的风速大于右侧;数值模拟分析表明在影响局地强风过程的主要物理因子中,风矢量的水平平流和气压梯度项的影响最重要;"莫兰蒂"台风的强风区呈现明显的中尺度特征,较高动量的空气垂直输送和动量下传作用导致眼壁周围风力增强。

Structure characteristics and cause analysis of catastrophic wind caused by super typhoon Meranti

Based on the observed data and simulated results, this paper studies the structure characteristics and cause of catastrophic wind caused by super typhoon Meranti(typhoon "1614"). It is the strongest typhoon affecting Xiamen since typhoon "5903", and its impact radius is relatively small. Before landing, the local strong wind in typhoon circulation is characterized by periodic fluctuation. The azimuth change of the local strong wind relative to the typhoon first turns clockwise, then turns counterclockwise with the typhoon approaching. Simulated strength of typhoon Meranti based on the wind-pressure relation is in good agreement with the observed result. After landing, typhoon Meranti is affected by terrain friction, which makes the wind speed on the left side of typhoon stronger than that on the right side. Numerical simulation analysis shows that the horizontal advection of wind vector and the pressure gradient term are the main physical factors causing the local catastrophic wind. The strong wind area of typhoon Meranti shows obvious meso-scale characteristics. Wind around the eye wall is strengthened by the vertical air transportation with higher momentum and the momentum downward propagation effect.