海洋动力系统数值模式体系及海浪-环流耦合理论

从系统科学的观点出发,把海洋运动按照时空尺度分解成小尺度(以海浪为代表)子系统、中尺度(以内波为代表)子系统、大尺度(以大洋波动和环流为代表)子系统,并把海洋和大气之间通过近海面海洋大气层进行相互作用的部分称为近海面海洋大气边界层子系统。考虑各子系统之间的相互作用,提出了从海洋动力系统观点出发发展海洋数值模式体系的科学思路。通过考虑海浪对环流的垂向混合作用,将海浪的运动混合作用解析表达为可以通过海浪数值模式直接计算的海浪谱形式,建立了海浪-环流耦合理论。这一理论不仅将普林斯顿环流模式全球上100米的模拟海温与Levitus资料之间的平均相关系数从0.58提高到了0.76,而且加深了我们对中国近海海洋环流系统的理解,同时对气候模式热带偏差这一共性问题有显著改善。该理论对海洋环境预报和全球气候变化预测具有重要意义。

Ocean Models System and the Surface Wave-circulation Coupled Theory

From the point view of system sciences, the ocean movement is divided into small-, meso-and large-scale subsystems according to temporal and spatial scales. Here we select the surface wave, internal wave and circulation as the representatives of the above subsystems respectively. The upper ocean and lower atmosphere constitute the fourth ocean subsystem in which air-sea interaction takes place. By considering the interactions among subsystems, we propose the idea to develop ocean numerical models system. In this kind of framework, a model focused on one subsystem should consider the effects of other subsystems. In tradition, a kind of numerical model isolates the focused subsystem from the whole system, and so does not consider the effects of other subsystems. As an example of ocean models system, the vertical mixing of the surface wave movement to circulation is analytically expressed as the function of wave number spectrum, and so the surface wave-circulation coupled theory is set up. Appling the theory to Princeton Ocean Circulation Model, we improve the global upper 100 m averaged correlation coefficient between modeled temperature and Levitus data from 0.58 to 0.76. And the model experiments improve our understanding of the coastal circulation in China Seas. The surface wave-circulation coupled theory can greatly improve the per-formance of the climate model, CCSM3, on tropical biases. The theory is important for the forecasts of ocean environments and climate changes.