Intensification and impact of wave-breaking in river plumes

锋面形成障碍，限制了海洋中不同水体之间营养物质和生物体的交换。这项研究将调查，如果波浪破碎可以加强之间的淡水河流羽状流和周围的海水离岸前的混合。 这项工作还将有助于对影响海洋无数过程的波浪破碎和近地表湍流的一般理解。该项目将支持一名研究生和几项外展工作，包括维护一个研究博客和制作一个视频片段，该视频片段将由应用物理实验室/华盛顿大学网站托管。该项目将使用一个新颖的波浪湍流测量平台来量化波浪能量的转化，因为它通过河流羽流前部和内部，以及破波湍流对羽流动力学和混合的影响。首要的假设是，羽流速度梯度可以加剧波浪破碎，将波能转化为湍流，并显着增加羽流混合系统中的波尺度匹配的垂直羽流规模。该计划是通过使用新的和现有的现场数据追求以下三个具体目标来测试这一假设：1）通过在前沿和河流羽流内破碎来量化波浪能量的损失，2）量化波浪破碎过程中近表面湍流的产生和这种湍流的垂直结构，以及3）评估波浪破碎湍流对河流羽流混合的影响。将在中等规模的弗雷泽河羽流（加拿大不列颠哥伦比亚省）和较小规模的埃尔瓦河羽流（美国华盛顿）的一系列波浪条件下，对波浪、近地表湍流和浮力通量进行测量。这些测量结果将与现有的波和湍流数据从更大的哥伦比亚河羽流，以确定如何波湍流动力学的影响，在不同的系统锋面强度进行比较。这一过程对混合的影响将使用漂流物盐预算以及通过弗雷泽河羽流的十多年轮渡样带数据分析进行评估

Fronts form barriers that limit the exchange of nutrients and organisms between different water masses in the ocean. This study will investigate if wave breaking can intensify mixing at fronts between an expanding fresh water river plume and the ambient salt water offshore. The work will also contribute to the general understanding of wave-breaking and near-surface turbulence, which influence a myriad processes in the ocean. The project will support one graduate student and several outreach efforts which include maintaining a research blog and producing a video segment which will be hosted by the Applied Physics Laboratory/University of Washington website.This project will use a novel wave-turbulence measurement platform to quantify the transformation of wave energy as it passes through a river plume front and interior, as well as the impact of wave-breaking turbulence on the dynamics and mixing of the plume. The overarching hypothesis is that plume velocity gradients can intensify wave breaking, converting wave energy to turbulence, and significantly increasing plume mixing in systems where the wave scales match the vertical plume scale. The plan is to test this hypothesis by pursuing the following three specific objectives using new and existing field data: 1) quantify the loss of wave energy via breaking at fronts and within river plumes, 2) quantify the generation of near-surface turbulence during wave breaking and the vertical structure of this turbulence, and 3) assess the impact of wave breaking turbulence on mixing in river plumes. Measurements of waves, near-surface turbulence, and buoyancy flux will be done in the moderate-sized Fraser River plume (British Columbia, Canada) and the smaller-sized Elwha River plume (Washington, USA) under a range of wave conditions. Results from these measurements will be compared with existing wave and turbulence data from the much larger Columbia River plume to determine how wave-turbulence dynamics are influenced by frontal strength in different systems. The impact of this process on mixing will be assessed using drifter-based salt budgets as well as analysis of more than a decade of ferry transect data through the Fraser River plume