裂流危险性的数值预报方法及其在三亚大东海浴场的应用

A numerical forecasting method of the hazard of rip current and its application in Dadonghai beach, Sanya

在简要综述裂流观测和预报进展的基础上,提出了一种裂流危险性的数值预报流程,并以三亚大东海浴场为例进行了裂流危险性后报试验。采用GPU并行加速的全非线性Boussinesq波动模型(FUNWAVE-GPU),在大东海浴场建立了水平分辨率为1 m的波动及波生流数值模型。通过施加不同潮位、入射波高、波周期和入射角度,考察裂流的产生和时空分布特征,结果发现入射波高及入射波周期的增大会使裂流空间尺度和流速明显增加,低潮位时更易产生裂流。将国家海洋环境预报中心提供的三亚外海波浪谱作为FUNWAVE-GPU的开边界条件,以离岸流强度及其持续时间作为裂流危险性等级的判定标准,绘制了国内首幅基于数值预报的裂流危险性等级图。

Based on a brief review on the progress of the observation and forecasting of rip current, this paper proposes a numerical forecasting procedure of rip current hazard, and takes the Dadonghai Beach, Sanya as an example to conduct the rip current hindcast experiment. Using the FUlly Nonlinear Boussinesq WAVE model accelerated by GPU(FUNWAVE-GPU), a numerical model of wave-driven currents with the resolution of 1meter is established in this study. The temporal and spatial distributions of rip currents are researched by imposing different tide levels, incident wave heights, periods and angles. It is found that the increase of incident wave height and periods would significantly enhance rip current speed and extend offshore-directed rip scales. In addition, the rip currents are more likely to occur at low tides. Using the wave spectrum off Sanya sea area provided by the National Marine Environmental Forecasting Center as the open boundary condition of FUNWAVE-GPU, and taking the intensity and duration as the criteria of the levels of rip current hazard, a hazard level chart of rip current is drafted for the first time in China based on numerical prediction.