东海陆架水对黑潮水入侵的动力学响应

Dynamical impact of Kuroshio intrusion on the shelf water of the East China Sea

黑潮冲击东海陆架的动力学效应可分解为两部分,即黑潮水直接入侵和黑潮强剪切作用。此文研究了东海陆架水对黑潮水直接入侵的动力学响应。入侵黑潮水(下层水)与陆架水(上层水)形成两层层化流动,视陆架为扇形海域,且海底地形等深线也呈扇形分布,针对该浅海分层流,采用作者已导出的改进的涡度方程,利用极坐标及Fourier级数求解方法得到了解析解。结果表明黑潮水从台湾岛东北部冲入陆架下层一定距离后逐渐右转,然后沿扇形分布的等深线运动。该冲击流在台湾岛东北部形成下层海水的下沉和上层陆架水的涌升,从而给出了该冷涡生成机制的一种动力学解释。该海水涌升区与红外卫星照片中呈现的台湾岛东北部的冷涡位置是一致的。

The dynamical impact of Kuroshio intrusion on the shelf water of the East China Sea contains 2 parts： the direct intrusion of Kuroshio water and the intensive shearing of Kuroshio.In this study,the directly intrusion is studied.Since the intrusion water of Kuroshio（lower level） and the shelf water（upper level） are stratified by two layers,the vorticity equation is modified.In this equation,the shelf and the isobaths are all treated as sector and a polar coordinate and Fourier series is employed to derive the analytical solution.The results indicated that the Kurochio water intrude upon the lower level shelf from north-east of Taiwan Island for a finite distance,then turn to the right along the isobaths of the fan-shaped topography.The intrusion current caused the downwelling of the deeper water and upwelling of the upper water around the north-east of Taiwan Island.The upwelling region is consistent with the location of the cool eddy which is observed from infrared satellite image of sea surface temperature,therefore the formation mechanism of cool eddy is given from the aspect of dynamics.