基于WRF-SWAN耦合模式的台风“威马逊”波浪场数值模拟

获取高分辨率的风场数据和气压场数据是精确模拟台风浪的基础,采用经验公式构建台风风场和气压场对海浪模式进行驱动,无法反映台风影响下海气动力过程,难以提供高精度的风场、气压场数据。本文基于中尺度大气模式WRF(Weather Research and Forecasting model)和第三代海浪模式SWAN(Simulating WAves Nearshore model),构建了南中国海地区大气—海浪实时双向耦合模式,针对超强台风"威马逊"进行数值模拟。将数值模拟结果与现场观测结果及卫星高度计观测结果进行对比验证,验证结果表明,本文建立的WRF-SWAN耦合模式在对台风"威马逊"影响下的南中国海台风浪的模拟中展现出较高的模拟精度,揭示了台风风场分布和台风浪分布在空间上的"右偏性"不对称分布特征及其形成机制。基于WRF和SWAN建立的大气-海浪实时双向耦合模式能够准确模拟台风动力过程以及台风浪的时空分布特征,可以推广用于南中国海地区台风浪的模拟分析。

Simulation of extreme waves generated by Typhoon Rammasun (1409) based on coupled WRF-SWAN model

Obtaining high-resolution field data of typhoon wind and pressure is the basis of accurate simulation of extreme waves. In previous studies, wind and pressure fields of typhoon were constructed using an empirical model and were used to drive the wave model; however, this method cannot reflect the air dynamic process under the influence of typhoon, and it is difficult to provide high-accuracy data of wind and pressure fields. In the present study, a real-time two-way coupled atmosphere-wave model in the South China Sea (SCS) has been established based on the WRF model and SWAN model, and extreme waves generated by Typhoon Rammasun (1409) were numerically simulated. The results of the numerical simulation were compared with the results of the field observation and the satellite altimeter of Jason-2. The verification results showed that the coupled WRF-SWAN model has a high accuracy in the simulation of extreme waves under the influence of Typhoon Rammasun in the SCS. The simulation results reveal the asymmetrical distribution of wind field and extreme wave field generated by Typhoon Rammasun, and the spatial distribution. The intensity of the typhoon on the right is greater than that on the left of the typhoon track. The real-time two-way coupled atmosphere-wave model based on the WRF model and SWAN model can accurately simulate the dynamic process of typhoon and the temporal and spatial distribution of the extreme waves generated by typhoon; thus, the model can be extended to the simulation analysis of waves in the SCS generated by other typhoons.