Intrusion of Less Saline Shelf Water into the Kuroshio Subsurface Layer in the East China Sea
Intrusion of Less Saline Shelf Water into the Kuroshio Subsurface Layer in the East China Sea
复制标题
DOI：
10.1007/s10872-004-5778-6
复制
发表时间：
2004
影响因子：
2.3
通讯作者：
A. Isobe;Eiji Fujiwara;Pil-Hun Chang;Koichi Sugimatsu;M. Shimizu;T. Matsuno;A. Manda
中科院分区：
文献类型：
--
作者：
A. Isobe;Eiji Fujiwara;Pil-Hun Chang;Koichi Sugimatsu;M. Shimizu;T. Matsuno;A. Manda
利用1998-2001年5月的观测资料，结合日本海洋资料中心的资料和数值模式，对东海陆架边缘黑潮次表层海水盐度偏低的可能原因进行了分析。观测结果表明，5月份在24.5σθ等密度面以上的地层中，总是检测到低盐水的地下侵入，在黑潮锋面涡（或波）的波谷周围检测到盐水下面的盐水较少的区域）。分析表明，24.5σθ等密度面是早春黑潮密度跃层出露于浅海陆架的最深层。在24.5σθ以上出露的等密度线遇到一个来自长江的较弱的盐水羽，特别是在东海西部。此后，低盐度水沿着等密度层运动，到达陆架边缘附近的黑潮锋。数值模型表明，当锋面波捕获的盐水较少，陆架水的形式，在槽中的盐度反演，因为锋面波的等盐线有一个相位之间的上层和下层的斜压不稳定的后果。
The possible origin and cause of the less saline shelf water detected in the Kuroshio subsurface layer around the shelf edge of the East China Sea are investigated using observational results obtained in May 1998–2001 in conjunction with a dataset archived by Japan Oceanographic Data Center and a numerical model. The observations show that subsurface intrusions of less saline water are always detected in May in layers above 24.5σθisopycnal surface, and that salinity inversions (i.e., areas in which the less saline water lies beneath the saline water) are detected around the trough of the Kuroshio frontal eddy (or wave). Analyses of the archived dataset reveal that the isopycnal surface of 24.5σθis the deepest layer of the Kuroshio pycnocline outcropping to the sea surface on the shallow shelf in early spring. Outcropping isopycnals above 24.5σθencounter a less saline water plume originating from the Changjiang, especially in the western East China Sea. Thereafter, the less saline water moves along isopycnal layers and reaches the Kuroshio front around the shelf edge. Numerical models demonstrate that, when the frontal wave captures the less saline water, the shelf water takes the form of a salinity inversion in the trough because isohalines in the frontal wave have a phase lag between the upper and lower layers in consequence of the baroclinic instability.