Numerical Modelling of the Philippine Sea

Abstract

Abyssal circulation is investigated using a linear reduced gravity model. First, effects of the location of an inflow on the abyssal circulation is studied using an idealized simple model. It is shown that a stagnation point disappears when an inflow is located north of the latitude of a stagnation point expected from the Stommel-Arons theory in the northern hemisphere. Second, the abyssal circulation in the Philippine Sea is studied using a model with realistic coastal and topographic geometries. It is assumed that the bottom water is supplied from the main western North Pacific into the Philippine Sea through the Yap-Mariana Junction as suggested by observations. Numerical experiments are carried out for models with and without bottom topography. In results for the model without bottom topography the strong abyssal boundary current is formed along the western and northern boundaries, and a stagnation point, not formed. Results from the experiment including a topographic effect show that abyssal circulation in the eastern Philippine Sea (the Shikoku and West Mariana Basins) is more active than that in the western Philippine Sea (the Philippine Basin). It is encouraging to see that a modelled circulation pattern compared well to observational results obtained by mooring current meters and hydrographic data in spite of the simplicity of the model.