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RAPID项目，由于时间紧迫，评估和资助进度加快。Jim Nelson， H. Seim和C. Edwards最近资助了一项提案（NSF-OCE生物和物理海洋学项目，奖励1032285和1032276），重点研究冬季在长湾外大陆架/上斜坡（位于南卡罗来纳州罗曼角和北卡罗来纳州费尔角之间）的物理-生物耦合。在这个地区，拉长的陆架边缘浮游植物开花特征在冬季卫星图像中很常见。与南大西洋大陆架的其他部分不同，在那里，与墨西哥湾流锋面漩涡相关的大陆架边缘上升流是支持大陆架新产品的最大营养来源，在长湾，似乎其他过程必须维持整个冬季浮游植物的大量繁殖。Nelson等人的工作将使用系泊、滑翔机、船舶和卫星测量来研究这些其他大陆架边缘物理机制的物理和生物方面。该项目将利用现有的高频雷达仪器，在实验中增加远程高频雷达表面电流测量，从而扩大科学测量的范围。这些雷达的部署将使收集表面洋流的数据成为可能，其空间分辨率为3000米，时间频率为30分钟及以上，范围可达墨西哥湾流。两个波束形成，韦伦雷达（WERA）可在南卡罗莱纳大学（伏尔加罗斯）用于该项目。这种部署适合作为RAPID项目的一个主要原因是，由于其作为国家高频雷达网络的一部分的专用任务意外停机，两台雷达中的一台最近才可用。在纳尔逊等人最初提出建议的时候，不可能将该雷达投入到他们的项目中，但是操作的中断使该系统暂时可用于集中的科学研究部署。该部署的必要任务，如修改其中一个雷达的频率，从FCC获得无线电许可证，找到合适的位置并获得许可，需要迅速启动，以便及时部署这些系统，与Nelson等人计划于2012年1月下旬部署的系统同时运行。建议的数据收集将对Nelson等人资助的工作做出重大贡献，通过提供他们在高空间和时间分辨率下定义墨西哥湾流离岸位置和方向的能力显著提高。假设在这些设施上有互联网通信的可用性，实时地表水流地图可以为Nelson等人项目的船舶和滑翔机操作做出贡献。在现有的ioos支持的乔治亚大陆架雷达覆盖范围上增加长湾雷达部署，将有可能对比乔治亚大陆架和长湾之间风致大陆架流动、内部潮汐和大陆架边缘漩涡的表面表达，并确定它们与不同模式的湾流变化的对应关系。这将进一步允许在比过去更大的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大陆架进出口。全球沿海海洋中新定义的反硝化过程（汇）意味着比目前确定的固定和输入速率（源）要高得多，因此需要对陆架边缘的硝酸盐源进行更准确的计算。在南大西洋湾，陆架衍生碳源的出口和硝酸盐进入沿海海洋的进口都受到很差的限制，并且可能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对该地区冬季强迫的贡献。这一合作还将加强邻近的北卡罗来纳州、南卡罗来纳州和佐治亚州之间的合作，从而在物理海洋学领域形成潜在的区域协同效应，使这三个地区都受益。

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.