基于选定风浪方向谱的海浪模拟方法(英文)

简要回顾当前第三代海浪模式中的困难。为避开这些困难，作者提出一种新的海浪模拟方法，其中特定定义的风浪组成波依常风下随时间成长的方向谱计算，而涌浪组成波藉考虑涡动黏性和底摩擦加以计算。并进行了常风场和变风场下系统的数值试验。在常风速情形中，模拟结果能精确地化为建立模拟所根据的谱和风浪成长关系。计算显示出台风中心附近浪场的极端复杂的谱结构。当风速骤然降低时，模拟的波高减小与观测符合。在风向逐渐或骤然改变情形下，计算的时间响应尺度与海上观测符合，而且演化中的二维谱结构得到良好刻画。对于涌浪在无风下的传播，模拟结果合理，包括波参量及谱结构的变化。后报得到的波高、周期和海上资料符合。与第三代模式相比，文中提出的方法较易改进，需用的计算机时间显著减少。最后讨论采用一个已知谱来建立谱形式的海浪预报模型的合理性以及有关的问题。

Wave Modeling Based on an Adopted Wind WaveDirectional Spectrum

The difficulties in the current third generation wave model are briefly reviewed. To bypass these difficulties, a new approach to wave modeling is proposed in which specifically defined wind wave components are calculated by using a directional spectrum growing with time under constant wind while the swell components are calculated by considering turbulent viscosity and bottom friction. Systematical numerical experiments have been performed under constant and varying winds. In the case of constant wind, the simulated results can accurately reproduce the spectrum and wave growth relation on which the proposed model is based. Computations reveal the extremely complicated spectral structures of the wave field near a hurricane center. When wind speed suddenly drops, the simulated decrease of wave height is consistent with observations. In the case of gradual and abrupt shift of wind direction, computed response time scales agree with field measurements and the evolving two dimensional spectral structures are well depicted. Swell propagating in the absence of wind is simulated with reasonable results, including the change of wave parameters and spectral structures. Hindcast wave heights and periods agree with field data. The proposed modeling is capable of being improved more easily and requires much less computer time to run than the third generation model. The justification for employing a given wind wave spectrum to build a spectral wave model and other related issues are discussed.