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四、海浪的数值预报方法 到目前为止,海浪的数值预报模式基于谱组成波的能量平衡方程以数值计算方法而建立的,实质上都是以下述能量平衡方程为基本方程:式中F是二维波谱,是频率f、传播方向θ、时间t和位置x的函数,Cg为波群速度,S为源函数,包括风作用项S_(in)、消衰项S_(ds)(包含波的破碎消衰、涡动粘性和逆风引起的消衰,浅水中海底和地形引起的消衰等)、波与波之间相互作用引起的非线性能量传输项S_(n1)。所谓海浪数值预报,就是将上述微分方程(或者是近似公式)进行数值积分。虽然不同的研究者采用描述组成波成长的方程有相同的形式,但由于所用的源函数不同,所以提出的数值模式就很多。经SWAMP小组对比,大致分三类:一是非耦合离散型模式(Decoupled Propa-gation),简称DP模式;二是耦合混合型模式(Coupred Hybrid),简称CH模式;三是耦合离散型模式(Coupled Discrete),简称CD模式。并根据各类模式的功能,将DP模式划为第一代海浪模式,CH和CD模式为第二代海浪模式。
So far, the numerical prediction model of ocean waves based on the energy balance equation of the spectral composition wave is established by the numerical calculation method. All of them are based on the following energy balance equation as the basic equation: where F is two The dimension spectrum is a function of the frequency f, the propagation direction θ, the time t and the position x, Cg is the wave group velocity, S is the source function, including the wind action term S in, the decay term S ds, Crushing and decaying, eddy viscosity and adverse effects caused by downwind, decay caused by shallow sea bottom and topography, etc.), nonlinear energy transfer term S_ (n1) caused by the interaction between wave and wave. The so-called ocean wave numerical prediction, is the above differential equation (or approximate formula) numerical integration. Although different researchers use the same form to describe the equations for the growth of constitutive waves, many numerical models are proposed due to the different source functions used. Compared with the SWAMP group, there are roughly three types: one is the Decoupled Propagation (DP) mode, the other is the Coupred Hybrid (CHD) mode, the third is the Coupled Hybrid mode Discrete), referred to as CD mode. According to the functions of various modes, the DP mode is divided into the first generation of wave modes, and the CH and CD modes are the second generation of wave modes.