黄海海浪季节变化的数值模拟研究

Numerical study of wave height seasonality in the Yellow Sea

利用第三代海浪数值模式SWAN,研究了黄海海浪有效波高的季节变化特征及相关的物理过程。结果表明,在黄海的大部分区域,混合浪有效波高的最大值出现在冬季,而最小值则基本出现在夏季。北黄海北部和山东半岛南岸的近海海域呈现稍微不同的季节变化,有效波高的最大值出现在春季。全年4个季节中混合浪有效波高的空间分布基本一致:均在济州岛西南最大,沿黄海中部区域向北和由中部区域向近岸区域逐渐减小。黄海海浪为风浪占主,涌浪有效波高远小于风浪有效波高。在黄海的大部分区域,白冠耗散和四波非线性相互作用对黄海海浪的季节变化均至关重要;对于外海区域,四波非线性相互作用更为重要,而对于近海区域,白冠耗散则影响更大。本研究旨在研究黄海海浪的季节变化特征及其物理过程,为进一步探讨该海域海浪在其他时间尺度上的变异特征和动力学过程提供研究基础。

In this study, using the third-generation Simulating WAves Nearshore （SWAN） ocean-wave model, we investigate the seasonality of the significant wave height （SWH） of ocean surface waves in the Yellow Sea （YS） and the associated physical processes. The results show that in most areas of the YS, generally, mixed-wave SWHs are at their maxima in winter and minima in summer. However, in the northern part of the YS and the offshore area south of the Shandong Peninsula, mixed-wave SWHs show slightly different seasonal variations, with their maxima appearing in spring. In the four annual seasons, mixed-wave SWHs basically show the same spatial distributions; i.e., the values are the largest southwest of the Jizhou Island and then decrease both northward and shoreward. The ocean waves in the YS are dominated by wind-sea. The swell height is much smaller than the wind-sea height. In most regions of the YS, whitecapping and four-wave nonlinear interactions decisively affect the seasonal variations in the mixed-wave height. In deep water, four-wave nonlinear interaction is more important than whitecapping, whereas in shallow water, whitecapping is more important. In this study, we examine the characteristics and physical processes of seasonal wave-height variations in the YS, which will further advance our understanding of wave-height variations in other time scales and will be useful in evaluating the temporal variations of wave energy on various time scales.