巴士海峡水质点运动路径的分布特征

CHARACTERISTICS OF WATER PARTICLE MOTION PATHS IN THE BASHI STRAIT

为了探讨巴上海峡东侧的黑潮水是否通过巴士海峡进入南海东北部以及进入后的去向如何，首次采用数值模拟方法跟踪了巴士海峡经向断面网格点水质点冬、夏季的空间运动路径。结果表明，冬、夏季均有西太平洋黑潮水通过巴上海峡经向断面的中、南部进入南海东北部，形成黑潮南海分支。并直“套状”结构，夏季黑潮南海分支的“套状”结构比冬季的明显。冬季，进入南海东北部的黑潮水有部分可到达10．0°N以南的南沙海域。

To study if Kurshio Water (KW) PaSses through the Bashi Strait (BS), and to identify its path after passing through BS, 3D motion paths of water particles were traced on grids for a BS longitudinal section in winter (January) and summer (July) using a tracing model. The results indicate that KW passed through the Anddie and southern paths of the BS longitudinal section to reach the northeastern South China Sea (SCS), to form the Kuroshio Branch in the northeastern SCS (KB NSCS) in winter and summer. In winter, the KBNSCS branch es off near 21.5° N 114. 5°E,southeast of the Dengsha Islands. The motion paths of water particles have loop like structures in the northeast of the Branaching off Location (BL) and come into the westem Pacific Ocean (WPO) from the north of the BS. Layers 1-6, a part of motion paths of motion paths in the northeast of BL stretch downward, another part parallels the continental slope isobaths into WPO. No motion paths reach the continental shelf near Taiwan Shoal, which implies that the winter upwind flows coming from the northeastern SCS to enter Taiwan Strait are indirect geostropic upwind flows, most of the water of which does not come from KW directly. Layers 5-7 motion paths can reach the Nansha district south of 10.0°N in summer, when the BL of KBNSCS moves eastward. In Layers 1 and 2, the motion paths to the northeast of the BL are northward continuously and pass through Taiwan Stait after reaching the continental slope. The looped motion paths in the north of the BS in summer are more remarkable than those in winter, but the motion paths at the southwest of the BL do not reach the Nansha district.