Abyssal circulation model of the Philippine Sea

Abstract

The abyssal circulation in the Philippine Sea is investigated by use of a linear reduced-gravity model. It is assumed that the deep water is supplied from the main western North Pacific into the Philippine Sea through the Yap-Mariana Junction, as suggested by observational results. Two different numerical experiments are carried out, with and without bottom topography. The results of the flat-bottom model show that a strong abyssal boundary current is formed along the western and northern boundaries. However, a stagnation point cannot be found in this case. Although the results from the experiment that includes topographical effects display a complicated pattern, abyssal water flowing into the Philippine Sea mainly appears to move northward in the West Mariana Basin. Also, the Model results suggest that the abyssal circulation is more active in the eastern Philippine Sea (the Shikoku and West Mariana Basins) than in the western Philippine Sea (the Philippine Basin). It is remarkable that not only the circulation pattern but also the relative strenghts of the current velocity from the present model are fairly consistent with the observational results from moored current meters and hydrographic data, in spite of the simplicity of the model.