The Application Of HAMSOM Model On The Study Of Internal Tide In East China Sea

Internal tide is a low frequency internal wave with tide frequency. The study of internal tide has great scientific significance for the research for thermohaline circulation theory, and also has very important value in ocean environment, the protection of marine ecosystem, underwater communication, ocean engineering and military development.At present, it is generally believed that the mechanism of internal wave is the tide-topography interactions. The East China Sea and adjacent seas are one of the most significant generation regions of the M2 internal tide in the world's oceans. Nevertheless,there have been very few studies on internal tide in this area. This article uses HAMSOM (HAMburg Shelf Ocean Model) 3D continental shelf ocean model, inputs real submarine topography, monthly average salinity and temperature fields, and M2 tidal harmonic constants, to simulate the M2 internal tide of East China Sea, and then study the features of the M2 internal tide, calculate energy flux.Studies show that, the result of the harmonic analysis of model predictions is consistent with the analogue result witch is done by Niwa and Hibiya(2004),based on POM; and the harmonic analysis of model predictions is consistent with the amplitude and phase of M2 tide inversed through T/P satellite altimeter observation data. All this shows that the simulation of M2 tide of this sea area done by HAMSOM is not far off, and HAMSOM is practicable in this sea area. Then, choose different pionts in the shallow continental shelf area, area near the Ryukyu Islands, and the deep-sea region outside of the Ryukyu Islands, to analyze the vertical density fluctuation. The results show that isodenses are undulate, have Semidiurnal Tide period. And the amplitude of the isosteres near the Ryukyu Islands is very large, while it is small in the shallow continental shelf area, and it is secondary in the deep-sea region. Further study shows that, the period of the internal tide is determined mainly by the period of the barotropic tide. Using the model output calculates the M2 internal tide energy flux,and the simulated magnitude of internal tide energy flux is lkw/m-10kw/m,which is consistent with the magnitude of M2 internal tide energy flux simulated by predecessors.The energy flux near The Okinawa Trough northeast of Taiwan, Ryukyu Trench and the Tokara Strait is larger,which flows into the Pacific Ocean along the main east-west direction.Further extract the internal tide energy flux of study area from the TOPEX/POEISDON satellite altimeter data,then compare it with the modle results.The magnitude of energy flux extracted from T/P is lkw/m,which is consistent with the magnitude of M2 internal tide energy flux by predecessors using T/P source,but it is different to the model result,and this article explains the reasons about the differences.