黄海海浪天气时间尺度变化的数值模拟研究

摘要

Satellite observations indicate that the significant wave height (SWH) in the Yellow Sea (YS) exhibits significant variations in periods shorter than 12 days.The current study intends to investigate in detail the characteristics of the temporal and spatial variations in the weather with respect to the SWH in the YS as well as the associated dynamic processes based on Simulating WAves Nearshore (SWAN),a third-generation wave model.The results indicate that the strength of the weather variations in the SWH (denoted as Sw) shows strong characteristics in its temporal variations and spatial distributions.There is a high-value tongue of Sw extending from the south to north in the eastern-central part of the YS.Meanwhile,Sw decreases shoreward.It is largest in winter and smallest in summer.From November to May in the following year,the monthly climatology of Sw shows a spatial distribution similar to that of its annual mean.From June to October,however,there is a strong gradient in the monthly climatology of Sw perpendicular to the border between the YS and the East China Sea.Further analysis indicates that the Sw in the YS is dominated by windsea,with secondary contributions from swell.Numerical experiments prove that the weather variations in the SWH are caused by wind forcing with longer periods via four-wave nonlinear interactions.%利用第三代海浪数值模式(SWAN)系统研究了黄海海浪有效波高的天气时间尺度变化的时空分布特征和相关动力学过程.结果表明黄海海浪有效波高的天气变化强度(Sw)具有显著的时间变化特征和空间分布特征.其多年平均值在黄海的中东部存在由南向北延伸的高值区,同时向两侧近海区域逐渐减小.Sw在冬季最大,夏季最小.从11月到翌年5月,Sw月气候态平均值的空间分布与其年平均值的空间分布类似;从6月到同年10月,Sw的月气候态平均值在黄海与东海的分界处存在较强的由黄海到东海的空间梯度.进一步分析表明黄海海域的Sw以风浪占主,涌浪的贡献远小于风浪贡献.数值实验表明,黄海海浪有效波高的天气时间尺度变化主要是由大于天气变化周期的海面风强迫通过四波非线性相互作用产生的.