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

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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.