台风“彩虹”(1522)的数值模拟及增强条件分析

Analysis on the numerical simulation and enhancing conditions of typhoon "Mujigea"

利用WRF数值模式对台风"彩虹"进行数值模拟,较好地模拟出台风的移速路径、强度变化,登陆时间和地点与实况基本一致;利用高分辨率的模式输出,对台风增强条件进行分析,结果表明:(1)台风中心高空气流强烈外流区与高压反气旋环流中心靠近合并,中层呈"东北高西南低"的形势,副高中心的加强大大增强与台风之间的气压梯度力,均有利于台风强度增强;(2)小的各层VWS有利于台风加强;环流场的调整会使得各层VWS均有所增大,但台风仍在加强;深层和低层VWS先于台风减弱就开始增大,而高层VWS在台风减弱过程中仍维持较小;(3)台风强度的变化滞后于水汽净流入量的变化趋势约9小时,南边界为最主要的水汽输入,表明西南季风对台风水汽输送起着重要作用;(4)海表面输送的热量为台风发展提供能量来源的同时,其输送的不对称也是引起台风整体结构不对称的原因之一,其中潜热通量在台风加强过程中起到更重要的作用。

Based on the WRF numerical model, numerical simulation of typhoon ＂ Mujigea＂ was made to simulate the moving speed of the typhoon path, intensity changes, landing and location. The results are all consistent with the actual process. Using high-resolution model output, the typhoon to enhance conditions were analyzed, The results show that： （1） the typhoon center strong outflow area closing to the high pressure anticyclone circulation center, middle showing the situation of ＂ northeast high southwest low＂ , the greatly strengthening center of the subtropical and the pressure gradient force between typhoon is helpful for the enhancing the; （2） the small VWS of the each layers increase the strengthening of typhoon; Adjustment of circulation field makes the layers of VWS has increased, but the typhoon is still in strengthening; Deep and low-level VWS began to increase before the typhoon weakening, and high-level VWS remains small in the process of the typhoon weakening; （3） The typhoon intensity changes lags the change of net water vapor flow trend about 9 hours, south boundary as the major water vapor input, plays an important role in the southwest monsoon typhoon water vapor transportation; （4） the heat of the sea surface providing energy sources for the typhoon development, its transmission asymmetry is also one of the causes of the typhoon asymmetric structure, in which the latent heat flux plays a more important role in the process of typhoon strengthening.