Quantifying exchange between the surfzone and a stratified inner-shelf with dye tracer experiments

通过染料示踪实验量化表面区和分层内架之间的交换

• 批准号: 1459389
• 负责人: Falk Feddersen
• 金额: $ 99.68万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2021-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1459389&HistoricalAwards=false
• 关键词: Quantifying; exchange; between; surfzone; stratified

The surfzone and inner-shelf are by far the most economically and ecologically important ocean regions, vital for recreation, food, and ecosystem services. Despite the importance of clean coastal waters to our economy and well-being, declining water quality threatens coastal ecosystem and human health worldwide. Healthy coasts are a significant priority to federal agencies, local government, and non-governmental organizations. This study will use dye release experiments to quantify the exchange between the inner-shelf and the surfzone, improving scientific understanding and thus allowing for accurate prediction of tracer (e.g., larvae, nutrients, pathogens) exchange from the surfzone through the inner-shelf in the San Diego South Bay. This region is a representative surfzone and inner-shelf system, allowing project results to be applied generally. This region also is home to economically valuable beaches, State Parks, a Marine Protected Area, and a National Estuarine Research Reserve, among other assets. Yet, it is often impacted by poor water quality. This study will provide local managers and citizens insight into regional tracer exchange. The investigators will train a PhD student and engage undergraduates through the Scripps Institution of Oceanography Research Experience for Undergraduates program. Additionally, they will host three SurfScience Teen Conferences for high-school students, develop collaborations with students at the underserved Kearny High School (San Diego, California), and participate in the annual Avanzamos conference which introduces young Latinas to ocean science.During this study the analysis of observations and model results will improve the understanding of the physical processes governing tracer exchange between the surfzone and the stratified inner-shelf. By closing a tracer mass budget, dye fate can be accurately determined. Estimates of observed and modeled inner-shelf dye diffusivity will be used to test the extent to which the inner-shelf is a "material barrier". Inner-shelf lateral diffusivities (hypothesized to be smaller than the surfzone) may be comparable to or greater than surfzone diffusivities, as larger inner-shelf eddy length-scales may compensate for weaker eddy velocities. The source of stratified inner-shelf coherent structures with large length-scales (relative to surfzone generated rip currents) will be investigated. Shoreline dye observations far downstream and inner-shelf cross-shore dye flux measurements will determine the extent to which surfzone dilution mechanisms are or are not Fickian. The observations and model results will be used to determine how inner-shelf upper water column stratification is set by surfzone ejection of warm water. Lastly, the vertical mixing of tracer on the stratified inner-shelf will be diagnosed. Additional hypotheses driven modeling studies will be performed with varying stratification, wind, and rip current conditions

表面带和内大陆架是迄今为止最具经济和生态重要性的海洋区域，对娱乐，食物和生态系统服务至关重要。尽管清洁的沿海沃茨对我们的经济和福祉至关重要，但水质下降威胁着全球沿海生态系统和人类健康。健康的海岸是联邦机构、地方政府和非政府组织的重要优先事项。 这项研究将使用染料释放实验来量化内大陆架和表面带之间的交换，提高科学认识，从而允许准确预测示踪剂（例如，幼虫，营养物质，病原体）交换从冲浪区通过内架在圣地亚哥南湾。该地区是一个典型的冲浪带和内陆架系统，使项目成果得到普遍应用。该地区还拥有经济价值高的海滩、州立公园、海洋保护区和国家河口研究保护区等资产。然而，它往往受到水质差的影响。这项研究将为当地管理人员和公民提供深入了解区域示踪剂交换。 研究人员将培训一名博士生，并通过斯克里普斯海洋学研究所的本科生项目吸引本科生。 此外，他们还将为高中生举办三次SurfScience青少年会议，与服务不足的Kearny高中的学生开展合作（圣地亚哥，加州），并参加每年一度的Avanzamos会议，该会议向拉丁美洲的年轻人介绍海洋科学。在这项研究中，对观测结果和模式结果的分析将提高对控制冲浪带和海洋之间示踪剂交换的物理过程的理解。层内陆架 通过关闭示踪剂的质量预算，染料命运可以准确地确定。观察到的和模拟的内架染料扩散率的估计值将用于测试内架是“材料屏障”的程度。内架横向扩散系数（假设小于表面区）可能与表面区扩散系数相当或大于表面区扩散系数，因为较大的内架涡流长度尺度可以补偿较弱的涡流速度。将研究具有大长度尺度（相对于冲浪区产生的离岸流）的层化内陆架相干结构的来源。 海岸线染料观测远下游和内大陆架跨海岸染料通量测量将确定在何种程度上冲浪带稀释机制是或不是菲克。观测和模型结果将用于确定如何设置内架上层水柱分层的冲浪带喷射的温水。最后，对层化内陆架上示踪剂的垂直混合进行诊断。其他假设驱动的建模研究将在不同的分层、风和离岸流条件下进行