Observation of material fluxes through the Luzon Strait

Abstract

Based on field observations carried out in August, 2008, we obtained a set of data on velocity, hydrography, and hydrochemistry in the Luzon Strait, with which the velocity structure of the area, especially in deep channels, was analyzed, and the material fluxes, including water, dissolved oxygen, and nutrients were calculated. The results indicate that a net eastward water flux of 7.0 Sv occurred through the Luzon Strait. The deep layer flux in the southern part, through the deep channel, was westward with a value of 1.9 Sv, which confirms that deep Pacific water flows into the South China Sea via the deep passage in the Luzon Strait. Accordingly, the net flux of dissolved oxygen was 13.2×10⁵ mol/s, and the values for dissolved inorganic nitrogen, phosphate and silicate were 4.6×10⁴ mol/s, 2.4×10³ mol/s, and 8.9×10⁴ mol/s, respectively. Detailed descriptions of these material fluxes in the upper layer, the upper-intermediate layer, the lower-intermediate layer, and the deep layer through the Luzon Strait are discussed. These results and interpretations highlight the importance of material exchanges between the South China Sea and the Pacific Ocean.