Transport and fate of the Labrador Coastal Current

拉布拉多沿岸流的运输和命运

• 批准号: 2123128
• 负责人: Nicholas Foukal
• 金额: $ 175.95万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2123128&HistoricalAwards=false
• 关键词: Transport; fate; Labrador; Coastal; Current

The Labrador Coastal Current (LCC) transports fresh outflow from the Canadian Arctic Archipelago, Hudson Bay, and the Greenland Ice Sheet southward along the Newfoundland and Labrador Shelf. If mixed offshore into the boundary current of the subpolar gyre, the fresh water in the LCC has the potential to stratify the upper ocean and alter the Atlantic Meridional Overturning Circulation (AMOC). Yet very little is currently known about the transport of the LCC and whether the LCC interacts with the large-scale North Atlantic circulation, or remains on the shelf around the Grand Banks. This project would study the fate of the LCC and its transport along the Canadian Labrador and Newfoundland coastlines. Using a combined Eulerian and Lagrangian observational study, the project would examine whether the fresh, buoyant water in the LCC moves off the shelf to join the Labrador Current, hypothetically due to a combination of the region’s complex bathymetry and strong wind forcing. The work would support an early career researcher, provide project material for a summer undergraduate intern, and involve 7 students with cruise experience as watch standers.Four moorings will be deployed in summer for one year, along the Canadian Atlantic Zone Monitoring Program (AZMP) Seal Island hydrographic section inshore of Hamilton Bank, which will provide the first continuous volume and freshwater transport time series of the LCC. In addition, 46 surface drifters will be released into the LCC, in subsets at 15 day intervals, by three moored Submerged Autonomous Launch Platforms (SALPs). Two cruises will be conducted along the deployment and recovery efforts, collection high-resolution shipboard ADCP and CTD surveys of the Newfoundland and Labrador Shelf. Together with the historical AZMP hydrographic sections, the project will quantify transport and track the pathways and fate of the fresh water in the LCC, and will identify hot spots of shelf-basin exchange. Timing of the NASA Surface Water and Ocean Topography (SWOT) satellite launch and three-month “Fast- Sampling Phase” with daily flyovers may coincide with the drifter releases, and would provide high-resolution sea-surface height (SSH) and surface geostrophic velocities of the inner shelf, potentially broadening the spatial and temporal extent of this targeted study.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

拉布拉多沿岸流（LCC）将来自加拿大北极群岛、哈德逊湾和格陵兰冰盖的新鲜流出物沿着纽芬兰和拉布拉多大陆架向南输送。如果在近海混合到副极地环流的边界流，在LCC的淡水有可能分层上层海洋和改变大西洋经向翻转环流（AMOC）。然而，目前对LCC的运输以及LCC是否与大规模北大西洋环流相互作用或留在大浅滩周围的大陆架上知之甚少。该项目将研究LCC的命运及其沿着加拿大拉布拉多和纽芬兰海岸线的交通。该项目将使用欧拉和拉格朗日观测研究相结合的方法，研究LCC中的淡水浮力是否会离开大陆架加入拉布拉多海流，假设这是由于该地区复杂的水深测量和强风强迫的结合。这项工作将支持一个早期的职业研究人员，为暑期本科实习生提供项目材料，并涉及7名学生与邮轮经验作为watch standers.4系泊将部署在夏季为期一年，沿着加拿大大西洋区域监测计划（AZMP）海豹岛水文部分近岸的汉密尔顿银行，这将提供第一个连续的体积和淡水运输的LCC时间序列。此外，46个表面漂流物将被释放到LCC，在15天的间隔，由三个停泊的水下自主发射平台（SALP）。将沿着部署和回收工作进行两次航行，收集纽芬兰和拉布拉多大陆架的高分辨率船载ADCP和CTD调查数据。连同历史AZMP水文剖面，该项目将量化运输和跟踪LCC中淡水的路径和命运，并将确定陆架-盆地交换的热点。美国航天局的地表水和海洋地形卫星发射和为期三个月的“快速取样阶段”的时间安排可能与漂流物释放的时间相吻合，并将提供高分辨率的海面高度和内大陆架的表面地转速度，这一奖项反映了NSF的法定使命，并被认为是值得的。通过使用基金会的知识价值和更广泛的影响审查标准进行评估来提供支持。