潮汐对东海陆架边缘处水交换的影响

Tidal effect on water exchange across the East China Sea shelf break

为探讨潮汐对东海陆架边缘处水交换通量的影响,本文基于ROMS海洋数值模式,对渤海、黄海、东海的潮汐、环流进行了模拟研究。研究结果显示,在水平方向上,潮汐效应主要影响我国台湾岛东北及日本九州西南的水交换,其中在台湾岛东北区域,潮汐效应通过增加黑潮分支流(KBC)的向岸及离岸速度来加强黑潮水的跨陆架交换。潮汐效应对200 m等深线处跨等深线流速的影响量值约为3~5 cm/s。从垂直方向上来看,潮汐效应能够影响到深度200m处水层的深层交换。进一步研究其作用机制,发现潮汐效应主要通过平流输送项来影响水体交换,而其对水体的水平及垂直扩散项的影响较小。

A successful simulation of tides and currents in the Bohai Sea,Yellow Sea,and East China Sea was developed based on the regional ocean modeling system(ROMS) in high horizontal resolution.The tidal effect on the water exchange at the East China Sea shelf break is discussed.According to the simulation results,in the horizontal direction,the tidal effect mainly affects the water exchange in northeast Taiwan and southwest Kyushu.In northeast Taiwan,the tidal effect enhances the exchange of Kuroshio across the shelf break by increasing the onshore and offshore velocities of the Kuroshio branch current(KBC).In the vertical direction,the tidal effect can affect the deep exchange of the 200 m water layer.The influence of the tidal effect on the velocities across the 200 m isobath is approximately 3–5 cm/s.The tidal effect mainly affects the water exchange through an advection term and slightly affects the horizontal and vertical diffusion terms.