Seasonal Link Between Deepwater Overflow Through the Luzon Strait and Deep Western Boundary Current in the Philippine Sea

Abstract

Abstract The cold dense water from the Pacific sinks to the deep South China Sea (SCS) through the Luzon Strait, driving the abyssal and overturning circulations in the SCS, and affecting the Indonesia Throughflow and its associated heat and freshwater fluxes. Combining the ocean bottom pressure data and the hydrographic data, we reveal the seasonal link between Luzon Strait deepwater overflow (LSDO) and deep western boundary current (DWBC) in the Philippine Sea. The seasonal variation in the DWBC dominates the pressure difference between the Pacific and the SCS by adjusting the temperature field on the east side of the Luzon Strait, which in turn contributes to the seasonal variation in the LSDO. The enhanced DWBC in summer/autumn carries more relatively cold water from the high latitudes to the east of the Luzon Strait, increasing the local density and leading to the enhancement of the LSDO in autumn.