一个热带太平洋上层海洋环流模式及其检验研究

An Oceanic General Circulation Model of the UpperTropical Pacific and Its Validation Studies

为进行ＥＮＳＯ的模拟与预测，在中国科学院大气物理研究所原有的较低分辨率全球海洋环流模式的基础上，引入依赖于Ｒｉｃｈａｒｄｓｏｎ数的垂直扩散方案和太阳短波辐射穿透的物理过程，发展了一个较高分辨率的热带太平洋上层海洋环流模式。利用该模式和１９８０～１９９５年大气强迫场的观测，进行了热带太平洋海温及环流的结构和演变的数值模拟研究，并利用美国国家环境预报中心（ＮＣＥＰ）的同时段的海洋同化分析，就海洋及其时间变化的三维特征，检验了模拟结果。首先，检验了该模式对ＥＮＳＯ事件的三维结构特征及其演变的模拟能力，结果表明：这１６年间所有冷暖事件的发生、发展和消亡均得到基本正确的模拟；海温异常的强度和结构特征与实况有偏差，尤其是次表层，距平量在赤道西太平洋和沿斜温层显著弱于实况；表层海温（ＳＳＴ）距平与实况较为接近，只是在日期变更线附近偏大。然后，强调海气耦合模式要成功预测ＥＮＳＯ，真正严峻的考验是海洋模式对次表层海洋的模拟能力，而不能仅仅满足于对ＳＳＴ的正确模拟。因此，为全面评估该海洋模式，探讨模式误差的原因，根据同化资料，找出年际变化和季节变化最显著的区域之后，检验了多年平均状态及其季节变化、年际变率及其季节变化等统计量。?

In order to undertake the simulation and prediction of ENSO, based on the global oceanic general circulation model with lower resolution developed by the Institute of Atmospheric Physics, Chinese Academy of Sciences, after the introductions of Richardson number dependent vertical diffusion and the physical process of solar short-wave radiation penetration, an oceanic general circulation model of upper tropical Pacific with higher resolution was developed. The numerical simulation studies on the structure and evolution of the temperature and circulation in the tropical Pacific Ocean were performed with this model and the observed atmospheric forcing fields from 1980 to 1995. And focusing on the three dimensional characteristics of ocean and its evolution, the simulated results were validated by using the oceanic assimilated analysis during the same period produced by National Center of Environmental Prediction (NCEP) in USA. At first, the ability of this model to simulate the three dimensional features of the structure of ENSO and their evolution was investigated. It was indicated that: basically, the creation, development and decay of all cold and warm events during the 16 years were modeled correctly. There were some errors in the strength and structure of oceanic temperature anomalies, especially, at the subsurface, in the western equatorial Pacific and along the thermocline, the temperature anomalies were significantly weaker than the observed ones. At the sea surface, the oceanic temperature (SST) anomalies were closer to observation and only larger than the observed in the vicinity of dateline. Then, it was emphasized that, the correct simulation of SST was not enough for the successes of atmosphere-ocean coupled model and the prediction of ENSO, the really stringent was the capabilities of oceanic model simulating the ocean at the subsurface. Therefore, in order to evaluate the oceanic model more comprehensively and approach the reasons of model's errors, after the regions with the most significant interannual and seasonal variability were found out based on the NCEP oceanic analysis, some statistical amounts, i. e., multiyear averaged state and its seasonal variations, interannual variability and its seasonal variations, were validated. The results indicated that the main features of statistical annual mean states of oceanic temperature and current were simulated correctly, but the errors were also obvious, particularly, there were large systematic errors in the simulations of some oceanic circulation systems at subsurface such as thermocline, equatorial trough, northern equatorial ridge, northern equatorial counter-current trough and equatorial under-current and so on. It was these errors that determine the spatial distributions of the modeling errors of other statistical amounts.