摘要:本文发展了一个可以适用于任意水平正交曲线坐标系的海洋模式动力框架，并将其应用于中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室发展的气候系统海洋模式LICOM2.0（LASG/IAP Climate system Ocean Model，version2.0）。在经纬网格坐标系下，新的动力框架与LICOM2.0原有的动力框架模拟结果完全一致。基于新的动力框架，海洋模式可采用能够准确描述北冰洋地形的三极网格，克服了LICOM2.0经纬网格版本必须将北极点处理为孤岛的缺陷，从而显著改进了模式对于北冰洋环流和北大西洋经圈翻转流函数（AMOC）的模拟能力。此外，引进三极网格还可以避免模式网格距随纬度增加而急剧减小带来的计算不稳定，在LICOM2.0的三极网格版本中，模式不需要采用任何空间滤波方案仍然能够保证计算的稳定性，从而与LICOM2.0的经纬网格版本相比，极大地提高了模式的并行效率，这一点在当水平分辨率提高到0.1度时表现得尤为明显，海洋模式的并行加速比可以从经纬网格版本的5.8左右提高到三极网格版本的15.0左右。
关键词:正交曲线坐标/
海洋模式/
动力框架/
三极网格
Abstract:In this study, an ocean model dynamical framework applicable to general horizontal orthogonal curvilinear coordinate is developed. It is implemented in a climate system ocean model LICOM2.0 (LASG/IAP Climate system Ocean Model, version2.0) developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS). Using the latitude-longitude coordinate, simulation results with the new dynamical framework and the original one used in the LICOM2.0 are identical. Based on the new dynamical framework, the ocean model exploits the "so-called" tripolar grid that is capable of describing the topography of the Arctic Ocean accurately, which helps to eliminate the shortcoming that the North Pole is treated as an isolated island in the LICOM2.0 standard version. Therefore, the model's performance in simulating the circulation in the Arctic Ocean and the Atlantic Meridional Overturning Circulation (AMOC) has been improved significantly. Additionally, introducing the tripolar grid can also avoid computational instability caused by the drastic decrease of grid interval with increasing latitude. In the tripolar grid version of LICOM2.0, the model can achieve computational stability without applying any space filtering technique. Accordingly, the model's parallel efficiency has been greatly improved compared with the standard version of LICOM2.0. It is especially true when the model's horizontal resolution increases to 0.1 degree, as the parallel acceleration ratio of the ocean model can be increased from 5.8 in the standard latitude-longitude grid version to about 15.0 in the tripolar grid version.
Key words:Orthogonal curvilinear coordinate/
Ocean model/
Dynamical framework/
Tripolar grid
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