长江口枯季北港淡水向北支扩展的动力机制

发布时间：2018-04-10 17:13

本文选题：盐水入侵 + 淡水通量　；参考：《水科学进展》2016年01期

【摘要】：2011年12月至2012年1月长江口的现场观测资料表明,大潮和大潮后中潮期间,北港的淡水向北支口门和下段扩展,减小了北支下段的盐度,而小潮及其后的中潮期间无此现象。为了确证淡水的来源,采用验证良好的三维数值模式再现了上述观测现象,并通过数值试验和淡水通量机制分解方法分析其动力成因。数值试验结果表明,大潮及其后的中潮期间,北港主槽流经北港北汊及其周围浅滩的水体是北支淡水的主要来源,拉格朗日余流输送是其向北支扩展的主要动力机制。北港北汊的增深增加了进入北支的淡水通量,减弱了北支的盐水入侵。偏北风风速的增加抑制了北港淡水向北支的扩展,增加了北支的盐水入侵。
[Abstract]:Field observation data from December 2011 to January 2012 at the Yangtze River Estuary show that during the spring tide and the middle tide after the spring tide, the fresh water of the North Port extends to the north branch gate and the lower section, reducing the salinity of the lower part of the northern branch, but not during the low tide and the middle tide after the spring tide.In order to confirm the source of fresh water, the above observed phenomena were reproduced by a well-verified three-dimensional numerical model, and the dynamic causes were analyzed by numerical experiments and decomposition of freshwater flux mechanism.The numerical results show that the main channel of the North Harbour is the main source of fresh water in the north branch and its surrounding shoals during the spring tide and the middle tide, and the Lagrangian residual current transport is the main dynamic mechanism of its extension to the north branch.The depth of the North Branch increases the fresh water flux into the North Branch and weakens the salt water intrusion into the North Branch.The increase of wind speed of north wind inhibited the expansion of fresh water to the north branch of North Port and increased the salt water intrusion of north branch.
【作者单位】：上海市水利工程设计研究院有限公司;上海围海工程技术研究中心;华东师范大学河口海岸学国家重点实验室;
【基金】：国家自然科学基金资助项目(41476077) 上海市科学技术委员会重点项目(14231200402)~~
【分类号】：P731.2

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