Low-salinity plume detachment under non-uniform summer wind off the Changjiang Estuary
Low-salinity plume detachment under non-uniform summer wind off the Changjiang Estuary
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长江口夏季非均匀风作用下的低盐羽流脱离
DOI：
10.1016/j.ecss.2014.10.012
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发表时间：
2015-04
期刊：
影响因子：
--
通讯作者：
Chen, Changsheng
中科院分区：
文献类型：
--
作者：
Ge, Jianzhong;Ding, Pingxing;Chen, Changsheng
过去，人们提出了两种物理机制，即大潮期间的斜压不稳定和强不对称潮汐混合机制，用于东中国海内陆架低盐度羽流的离岸分离。使用两个观测和一个全三维、高分辨率、非结构网格、自由表面、原始方程、有限体积社区海洋模式(FVCOM)重新审查了这两种机制。观测到的水流和盐度表明，烟羽具有两层系统的特征，上层主要由河道流量引起的浮力流驱动，下层主要受潮汐混合和整流控制。SATM机制的基础是没有根据观测到的洋流和羽状区周围的盐度进行校准的模式运行，因此应谨慎地将其应用于在ECS内陆架上观察到的实际情况。在不考虑潮汐混合的情况下，推导了BI机制。尽管BI仍然可以发生在包括潮汐在内的前锋区，但它不能产生在ECS内陆架上观察到的单一的、大的、分离的低盐度透镜。以过程为导向的模式试验结果表明，对于给定的河流流量和实际潮流，东南季风占主导地位的夏季西南风的空间不均匀可以增加锋面的空间变率，从而在东中国海的内陆架产生显著的离岸低盐度水分离。
In the past, two physical mechanisms, baroclinic instability (BI) and strong asymmetric tidal mixing (SATM) during the spring tidal period, were proposed for the offshore detachment of the low-salinity plume over the inner shelf of the East China Sea (ECS). These two mechanisms were re-examined using both observations and a fully three-dimensional (3-D), high-resolution, unstructured-grid, free-surface, primitive-equation, Finite-Volume Community Ocean Model (FVCOM). The observed currents and salinities showed that the plume was characterized by a two-layer system, in which the upper layer is mainly driven by the river discharge-induced buoyancy flow and the lower layer is predominantly controlled by tidal mixing and rectification. The SATM mechanism was based on the model run without calibration against observed currents and salinity around the plume region, so that it should be applied with caution to a realistic condition observed on the inner shelf of the ECS. The BI mechanism was derived under a condition without consideration of tidal mixing. Although BI could still occur along the frontal zone when tides were included, it was unable to produce a single, large, detached low-salinity lens observed on the inner shelf of the ECS. The process-oriented model experiment results suggest that for a given river discharge and realistic tidal flow, the spatially non-uniform southwesterly surface wind during the southeast monsoon-dominant summer could increase frontal spatial variability and thus produce a significant offshore detachment of low-salinity water on the inner shelf of East China Sea.
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DOI：
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发表时间：
1963
期刊：
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影响因子：
--
作者：
H. Mao
通讯作者：
H. Mao
DOI：
--
发表时间：
2013
期刊：
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影响因子：
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作者：
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作者：
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影响因子：
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作者：
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通讯作者：
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