Understanding tidally and atmospherically forced resonances in an Ocean Circulation Model in terms of free oscillations

近年来，对观测数据和模型数据的分析支持这样一种假设，即海洋潮汐在描述水团垂直混合过程中起着至关重要的作用。因此，海洋潮汐对海洋环流有相当大的影响。特别是，潮汐产生内波，内波通过破碎机制增强海洋中的垂直混合。这一过程主要发生在大陆架过渡带和开阔海洋的地形结构上，如大洋中脊。然而，在海洋模型中，垂直混合是以非常简单的形式处理的，大部分是水平均匀的，没有潮汐效应。对于可靠的气候预测，对潮汐混合过程进行适当的物理描述是必不可少的。在一种独特的方法中，在气候模型中实现了完整的太阳潮汐潜势。在本项目中，将通过实施对海洋垂直混合过程的内潮效应来推广这一方法。因此，有可能研究海洋潮汐在气候模型中的作用。此外，利用一种用自由振荡来描述周期运动的新方法，并结合上述海洋模型的结果，将在不同的时间尺度上分析全球海洋的振荡行为。因此，分析长周期大气强迫振荡和高频超载是可能的。本研究将包括其他模型方法和卫星观测的结果。

In recent years analyses of observational and model data supported the hypothesis that ocean tides play an essential role in the description of vertical mixing processes of water masses. Thus, ocean tides have a considerable influence on the ocean circulation. In particular, tides generate internal waves, which through breaking mechanism enhance vertical mixing in the ocean. This process occurs predominantly at continental shelf transition zones and at topographic structures in the open ocean, like mid ocean ridges. However, in ocean models vertical mixing is treated in a very simplified form, mostly horizontally uniform and without tidal effects. For reliable climate predictions, the appropriate physical description of the tidal mixing processes is indispensable. In a unique approach the complete lunisolar tidal potential is implemented in a climate model. In the present project, this approach will be extended through an implementation of the internal tide effect on vertical mixing processes in the ocean. Hence it will be possible to investigate the role of ocean tides in climate models. Furthermore, with a novel method to describe periodic motions in terms of free oscillations and with the results of the above mentioned ocean model, the oscillation behavior of the global ocean will be analyzed on different time scales. Thus, it is possible to analyze long periodic atmospheric forced oscillations and high frequency overtides. Results from other model approaches and from satellite observations will be included in this study.