Detachment of Low-Salinity Water From the Yellow River Plume in Summer
Detachment of Low-Salinity Water From the Yellow River Plume in Summer
复制标题
夏季黄河羽流低盐度水的脱离
DOI：
10.1029/2020jc016344
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发表时间：
2020
影响因子：
3.6
通讯作者：
Gao Huiwang
中科院分区：
文献类型：
--
作者：
Yu Xiaojie;Guo Xinyu;Gao Huiwang
历史水文资料表明，低盐度水可以在夏季从黄河羽流中分离出来。在这项研究中，使用三维数值模型研究了这种分离的机制，该模型再现了观察到的分离，包括分离的低盐度水斑块的位置和大小。敏感性试验表明，黄河口潮致余流和潮混合作用是黄河口大潮拆离的主要原因。在小潮向大潮过渡期间，北向潮致余流增强，南向密度驱动流减弱，形成净北向余流（0.03 m/s），将高盐度水输送到南部低盐度水域。同时，逐渐加强的潮汐混合也增加了表层盐度，这在低盐度水的中心区域明显。在这两种作用的共同作用下，低盐度水在大潮期间被分成两部分;即，发生了低盐度水的脱离。上述场景适用于无风条件。在夏季盛行东南风的情况下，东北风引起的表面流通过将分离的低盐度水向东北移动并扩大其尺寸来促进分离。相比之下，其他季节盛行的北风将低盐度的海水推向南方，然后沿着海岸沿着，阻碍了分离。因此，黄河羽流中低盐度水的分离只发生在夏季。
Historical hydrographic data reveal that low‐salinity water can detach from the Yellow River plume in summer. In this study, the mechanism of this detachment is examined using a three‐dimensional numerical model that reproduced the observed detachment, including the position and size of the detached low‐salinity water patch. Sensitivity experiments showed that tide‐induced residual currents and tidal mixing around the Yellow River mouth played key roles in the detachment during spring tide. During the transition from neap tide to spring tide, the intensification of the northward tide‐induced residual current and the weakening of the southward density‐driven current lead to a net northward residual current (0.03 m/s), transporting high‐salinity water to the southern area of low‐salinity water. Meanwhile, the gradually strengthened tidal mixing also increased surface salinity, which was apparent in the central area of low‐salinity water. With the combination of these two effects, the low‐salinity water was separated into two parts during spring tide; that is, detachment of low‐salinity water occurred. The above scenario works with a condition of no wind. With the prevailing southeasterly winds during summer, the northeastward wind‐induced surface current promoted detachment by moving the detached low‐salinity water northeastward and enlarging its size. In contrast, the northerly wind that prevails in the other seasons drove low‐salinity water southward, which then flowed along the coast and hindered detachment. Consequently, the detachment of low‐salinity water from the Yellow River plume occurs only in summer.