沿海复杂地形台风登陆过程风场多尺度数值模拟  

Multi-scale numerical simulation of the wind field over a coastal complex terrain during a typhoon landfall

作　　者：董浩天 陶韬 杜晓庆[1] DONG Haotian;TAO Tao;DU Xiaoqing(Shanghai University,Shanghai 200444,China;Tokyo Institute of Technology,Tokyo 152-8550,Japan)

机构地区：[1]上海大学,上海200444 [2]东京工业大学,日本东京152-8550

出　　处：《空气动力学学报》2021年第4期147-152,共6页Acta Aerodynamica Sinica

基　　金：国家自然科学基金(52008239)。

摘　　要：我国沿海地区的台风风场研究与预报具有显著的经济和社会效益。多尺度风场数值模拟方法是将WRF中尺度数值气象模拟同小尺度风场大涡模拟结合的数值模拟方法,可实现台风影响下沿海复杂地形风场的精细化研究。本文以2012年台风启德为背景,通过WRF模式有效再现了台风中心路径和近地平均风速风向的24 h时程;采用循环入流方法,将WRF得到的平均风剖面中加入高频风速成分,并作为复杂地形风场大涡模拟的入口条件,模拟近地风场的时间和空间分布。研究表明,台风登陆后受到沿海复杂地形的影响,近地流向湍流强度较海面上增强1倍左右,风速高频成分显著增强,并出现了0.73 m/s向下的竖向平均速度,对局部地区的抗风安全产生较为不利的影响。The research and forecast of typhoons in China's coastal regions have significant economic and social benefits.A thorough investigation of the wind field over a coastal complex terrain is performed using the multi-scale method which is a combination of the meso-scale WRF(weather research and forecasting)and the micro-scale LES(large eddy simulation).The 24-hour central route of typhoon Kai-tak in 2012,as well as the time series of 10-min averaged wind speed and direction at 100 m above the ground are produced by WRF.Based on the temporal-averaged wind speed profiles from WRF,a cycling turbulence generator is applied to obtain a quasi-stationary inlet condition for the LES simulation,which further yields temporal-and spatial-distributions of wind speeds near the ground.The numerical results agree reasonably well with site observations and show that the streamwise turbulence intensity near the ground doubles as the typhoon boundary layer marches from the ocean to the observation site.Meanwhile,the high-frequency wind velocities,which are related to the terrain effect,have been considerably enhanced.Also,a downward mean wind speed of 0.73 m/s occurs at the leeside of hills.As a result,strong gusts might occur in the surface layer above coastal complex terrain during the landfall of typhoon.

关 键 词：台风 多尺度 复杂地形风场 湍流 数值模拟 

分 类 号：TU312.1[建筑科学—结构工程] P429[天文地球—大气科学及气象学]