潮汐和潮流作用下1323号台风“菲特”台风浪数值模拟

Numerical simulation of typhoon waves with tide during 1323 typhoon “Fitow”

利用第三代近岸海浪模式SWAN(Simulating WAves Nearshore)建立了基于非结构网格的台湾海峡台风浪数值模型,并以WRF模式(Weather Research and Forecasting Model)计算得到的高分辨率台风风场作为驱动,模拟了1323号台风"菲特"影响期间台湾海峡波浪场的演变过程。以实测资料进行验证的结果表明:整个模拟过程风速的平均绝对误差为1.60 m/s,有效波高的平均绝对误差为0.42 m,计算结果较好地再现了"菲特"台风影响下海峡内波浪运动过程。通过对比数值实验分析了潮汐、潮流对台湾海峡台风浪的影响,分析表明:海峡内近岸浅水区域潮汐和潮流对波浪计算的影响显著,在考虑水位和流场后,计算得到的有效波高分布曲线呈现周期性振荡,且与潮汐周期变化一致,计算得到的有效波高绝对误差下降14%,近岸波浪数值模拟的精度得到了改善。

Using the third generation of wave numerical model SWAN（Simulating Waves Nearshore）, the typhoon wave model of the Taiwan Strait was established based on the unstructured grids. Driving by the high-resolution typhoon wind fields from the WRF（Weather Research and Forecasting Model）, the evolution of the wave field in the Taiwan Strait during the typhoon＂Fitow＂（1323） was simulated. After comparison with measured data, the results showed that the mean absolute deviation of the wind in the whole simulation process was 1.60m/s, and that of the significant wave height was 0.42 m, so the simulating results reflected the propagation processing of the wave in the strait well during the typhoon＂Fitow＂. After analyzing the effect of tide and currents on the typhoon wave by the comparison experiments, it showed that the influence of tide was significant in the shallow water of the strait. Moreover, after considering the effect of tide, the curves of calculated wave height showed signs of cyclical oscillation that were consistent with the tidal cycle, and the mean absolute deviation of calculated wave height decreased by 14 percent, so the accuracy of offshore wave numerical simulation in the strait was improved.