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A New Mechanism for Generation of Internal Waves

内波产生的新机制

基本信息

批准号：
NE/E01030X/1
负责人：
Vasyl Vlasenko
金额：
$ 5.96万
依托单位：
Plymouth University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FE01030X%2F1
关键词：
New Mechanism Generation Internal Waves

项目摘要

Oceanic internal waves have great implications for the efficiency of vertical water mixing, transport of pollutants and suspended matter. They produce shear currents and turbulence that mix water and supply nutrients from the abyss to the surface photic layer. These effects, in turn, play a major role in primary biological productivity and water quality of the basins. The present study will examine a new mechanism for internal wave generation which may occur at the intrusion of river waters into the sea. New series of satellite images taken recently in the areas of river plumes revealed an evidence of generation of internal waves by the head of a surface gravity current during its transition from a suprcritical regime of evolution when internal waves are effectively arrested by strong river discharge, to a subcritical one when they are released. In-situ measurement have shown that this mechanism of internal wave generation is quite effective at producing internal waves with amplitudes comparable with the total water depth, however it has not bee studied theoretically so far. This fact was a strong motivation for the present study. The proposal aims to fill the gap in understanding of physical processes controlling the internal wave generation at the frontal side of propagating river plume through the analysis of satellite images collected by the Institute of Oceanography of the University of Hamburg and through the development of an advanced numerical model and its application to the Columbia River plume, for which unique observational data were collected and published since 2003. The achievement of this basic goal will lead to an understanding of the mechanism of energy transfer from the gravity current to internal waves, and then to turbulence.

海洋内波对垂直水混合效率、污染物和悬浮物的输送具有重要影响。它们产生剪切流和湍流，混合水，并将深渊中的营养物质供应到表面的透光层。这些影响反过来又对流域的初级生物生产力和水质起着重要作用。本研究将探讨一种新的机制，内波的产生可能会发生在入侵的河流沃茨进入大海。最近在河流羽流地区拍摄的一系列新的卫星图像显示，有证据表明，在从超临界状态演变到亚临界状态的过渡期间，表面重力流的头部产生了内波，在超临界状态下，内波被强河流排放有效地阻止，在亚临界状态下，内波被释放。现场测量表明，这种内波产生机制在产生振幅与总水深相当的内波方面是相当有效的，但迄今为止尚未对其进行理论研究。这一事实是本研究的一个强大动机。该提案旨在通过对汉堡大学海洋学研究所收集的卫星图像进行分析，并通过开发一个先进的数值模型并将其应用于哥伦比亚河羽流，填补在了解控制传播的河羽流正面内波生成的物理过程方面的差距。自2003年以来收集并公布了其独特的观测数据。这一基本目标的实现将导致对重力流到内波，然后到湍流的能量传递机制的理解。