Seasonal Exchanges of the Kuroshio and Shelf Waters and Their Impacts on the Shelf Currents of the East China Sea
Seasonal Exchanges of the Kuroshio and Shelf Waters and Their Impacts on the Shelf Currents of the East China Sea
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DOI：
10.1175/jpo-d-15-0183.1
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发表时间：
2016-05
影响因子：
3.5
通讯作者：
Jia Wang;L. Oey
中科院分区：
文献类型：
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作者：
Jia Wang;L. Oey
以往的现场观测和模拟研究表明，黑潮通过陆架边缘的质量和动量交换，对东海陆架流具有显著的影响。在这里，本研究使用25年的漂流数据，由卫星和其他数据支持，而不是局部观测，以确定沿整个大陆架边缘的季节性跨大陆架交换。研究结果表明，黑黑岛从秋季向滨向，从春季向夏季向滨向，以台湾东北部的纬度最大。在春夏两季，黑潮在近海徘徊时，其影响仅限于陆架边缘。相比之下，当黑潮在秋季和冬季蜿蜒上岸时，强烈的大陆架入侵和跨大陆架交换就会发生。在强烈的东北风的作用下，漂浮物侵入台湾东北陆架，向北扩散至308N。大陆架上的强迫被确定为海平面向北下降，在台湾以北258 - 288N处最陡峭，但在更北的地方弱3倍。从数值模型计算得到的涡度收支表明，秋季和冬季的入侵主要是大陆架上的环境潜在涡度平流和沿等深线压力梯度作用于整个大陆斜坡水柱质量变化所产生的涡度平衡的结果。
Previous in situ observations and modeling studies have indicated that, through mass and momentum exchanges across the shelf edge, the Kuroshio can significantly influence the shelf currents of the East China Sea (ECS). Here, instead of localized observations, this study uses 25yr of drifter data, supported by satellite and other data to identify seasonal cross-shelf exchanges along the entire shelf edge. The authors show that Kuroshiomeandersonshorefromfalltowinterandoffshorefromspringtosummer,withthelargestamplitude northeast of Taiwan. The influence is limited to the shelf edge when the Kuroshio meanders offshore in spring and summer. By contrast, strong onshelf intrusions and cross-shelf exchanges occur when the Kuroshio meanders onshore in fall and winter. Drifters intrude onshelf northeast of Taiwan and spread as far north as 308N against the strong northeasterly wind. The forcing on the shelf is identified as a northward downsloping of the sea level that is steepest north of Taiwan at 258‐288N, but which is 3 times weaker farther north. The vorticity budget computed from a numerical model indicates that intrusion during fall andwinter is primarily a result of balancebetweenonshelfadvectionofambientpotentialvorticityandvorticityproductionbythealong-isobath pressure gradient acting on the changing mass of water column across the continental slope.