RAPID: Collaborative Research: HF Radar Surface Current Measurements in Support of Constraining Shelf Edge Exchange in the SAB Under Wind, Tidal and Gulf Stream Influence

这是一个快速奖，评估和资助的加速时间表，因为关键的时间压力。Seim和C.爱德华兹的重点是物理生物耦合在冬季的外大陆架/上斜坡关闭长湾（之间的罗曼角，南卡罗来纳州和恐惧角，北卡罗来纳州。在这一地区，细长的陆架边缘浮游植物水华特征是冬季卫星图像中常见的现象。不像其他部分的南大西洋湾陆架，在那里与湾流锋面涡相关的陆架边缘上升流是支持新的生产在货架上的营养物质的最大来源，它似乎在长湾，其他过程必须维持整个冬季的浮游植物水华。纳尔逊等人的工作将使用系泊、滑翔机、船舶和卫星测量来调查这些其他大陆架边缘物理机制的物理和生物方面。该项目将扩大科学的范围，使他们的一套测量成为可能，通过增加远程高频雷达表面电流测量的实验，使用现有的高频雷达仪器可用于这项工作。部署这些雷达将能够收集空间分辨率为3 000米、时间频率为30分钟的表层洋流数据，覆盖范围可达墨西哥湾流，南卡罗来纳州（Voulgaros）大学有两台波束成形Wellen雷达（WERA）可供本项目使用。这种部署适合作为RAPID项目的一个主要原因是，两部雷达中的一部最近才成为可用的，这是由于其作为国家高频雷达网络的一部分的专用使命的意外停机时间。在纳尔逊等人最初提出建议时，不可能将该雷达用于他们的项目，但这种运行中断使该系统暂时可用于重点科学研究部署。 该部署的必要任务，例如修改其中一个雷达的频率、从FCC获得无线电许可证以及找到合适的位置并获得许可，需要迅速开始，以便及时部署这些系统，与纳尔逊等人计划在2012年1月下旬部署的系统同时运行。智力优势拟议的数据收集将大大有助于资助纳尔逊等人的工作，通过提供一个显着的改善，他们的能力，以确定墨西哥湾流离岸位置和方向在高空间和时间分辨率。假设在设施处的互联网通信可用，实时表面电流图可以有助于纳尔逊等人项目的船舶和滑翔机操作。随着长湾雷达部署增加到现有的国际海洋观测系统支持的格鲁吉亚大陆架上的雷达覆盖范围，将有可能对比格鲁吉亚大陆架和长湾之间的风强迫沿大陆架流动、内部潮汐和大陆架边缘涡流的表面表达，并确定它们与湾流变化的不同模式的对应关系。这将进一步允许在比过去可能的更大尺度上评估这些风和墨西哥湾流影响的对比区域之间的沿大陆架辐合和离大陆架输入/输出。更广泛的影响全球沿海海洋中新定义的脱氮过程（汇）意味着比目前确定的更高的固定和输入速率（源），需要更准确地计算大陆架边缘的硝酸盐来源。在南大西洋湾，来自大陆架的碳源的出口和向沿海海洋进口硝酸盐的限制都很差，可能会以重要的方式促进全球碳和养分循环。这些测量将更好地限制这些贡献冬季强迫在这一地区。这项合作还将加强北卡罗来纳州、南卡罗来纳州和格鲁吉亚等相邻州之间的合作，从而在物理海洋学领域产生潜在的区域协同作用，使所有三个区域受益。

This is a RAPID award, evaluated and funded on an accelerated schedule because of critical time pressures.A recently funded proposal (NSF-OCE biological and physical oceanography programs, Awards 1032285 and 1032276) by Jim Nelson, H. Seim and C. Edwards focuses on physical-biological coupling during winter on the outer shelf/upper slope off Long Bay (between Cape Romain, SC and Cape Fear, NC. In this region, elongated shelf-edge phytoplankton bloom features are common occurrences in wintertime satellite imagery. Unlike other sections of the South Atlantic Bight shelf, where shelf edge upwelling associated with Gulf Stream frontal eddies is the largest source of nutrients supporting new production on the shelf, it appears that in Long Bay, other processes must sustain the phytoplankton blooms throughout the winter months. The Nelson et al. work will use mooring, glider, ship and satellite measurements to investigate both physical and biological aspects of these other shelf-edge physical mechanisms. This project will expand upon the scope of science made possible by their suite of measurements by adding long-range HF radar surface current measurements to the experiment, using existing HF radar instrumentation available for this work. Deployment of the radars will enable the collection of data on surface ocean current with a spatial resolution of 3000m and with a temporal frequency of 30 min and over ranges reaching the Gulf Stream.Two beam forming, Wellen Radars (WERA) are available at the University of South Carolina (Voulgaros) for use in this project. A primary reason this deployment is suitable as a RAPID project is that one of the two radars has only recently become available as a result of unanticipated down-time in its dedicated mission as part of the national HF-radar network. It would not have been possible to commit this radar to the Nelson et al project at the time of their original proposal, but this interruption in operation makes the system temporarily available for a focused scientific research deployment. Necessary tasks for this deployment, such as modifying the frequency of one of the radars, obtaining radio licenses from the FCC, and finding suitable locations and obtaining permissions need to be started quickly so as to deploy these systems in time for concurrent operation with the Nelson et al. scheduled deployment in late January 2012. Intellectual Merit The proposed data collection will contribute substantially to the funded Nelson et al. work by providing a significant improvement in their capacity to define Gulf Stream offshore position and orientation at high spatial and temporal resolution. Assuming availability of internet communications at the installations, real-time surface current maps can contribute to the ship and glider operations of the Nelson et al. project. With the addition of the Long Bay radar deployments to the existing IOOS-supported radar coverage on the Georgia shelf, it will be possible to contrast the surface expression of wind-forced alongshelf flow, internal tides and shelf edge eddies between the Georgia shelf and Long Bay, and determine their correspondence with different modes of Gulf Stream variability. This will further permit the assessment of alongshelf convergence and off shelf import/export between these contrasting regions of wind and Gulf Stream influence at larger scales than have been possible in the past.Broader Impacts Newly defined denitrification processes (sinks) in the global coastal ocean imply much higher fixation and input rates (sources) than are presently identified, requiring a more accurate accounting of nitrate sources at the shelf edge. The export of shelf derived carbon sources and the import of nitrate into the coastal ocean are both poorly constrained in the South Atlantic Bight, and may contribute to global carbon and nutrient cycles in important ways. These measurements will better constrain those contributions for winter forcing in this region. This collaboration will also enhance collaboration between the neighboring states of North Carolina, South Carolina and Georgia, leading to a potential regional synergy in the area of Physical Oceanography that could benefit all three regions.