Impact of the Keweenaw Current on Cross-Margin Transport in Lake Superior

基威诺洋流对苏必利尔湖跨界输运的影响

• 批准号: 9712871
• 负责人: Erik Brown
• 金额: $ 116.28万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-15 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9712871&HistoricalAwards=false
• 关键词: Impact; Keweenaw; Current; Cross; Margin

9712871 Brown Research will be undertaken in response to an Announcement of Opportunity (NSF 97-38) for Coastal Studies in the Great Lakes. This is a collaborative research project involving eleven investigators from five academic research institutions. The research is being conducted under the auspices of the NSF Coastal Ocean Processes (CoOP) program and the NOAA Coastal Ocean Program. This collaborative, interdisciplinary 5-year research program will entail an integrated program of field and laboratory studies and mathematical modeling to quantify the role of coastal currents and thermal fronts in mediating cross-margin transport in Lake Superior. The western shore of Lake Superior's Keweenaw Peninsula exhibits a dramatic coastal jet known as the Keweenaw Current. A strong, shore-parallel density front, the thermal bar, also is characteristic of this region and persists long into the summer. The goal of the proposed work is to determine the physical, chemical, and biological effects that arise from the intense physical forcing on this system, and specifically, to elucidate how these effects interact temporally and spatially to define distinct nearshore and offshore environments in Lake Superior. This project represents the first effort to model coupled physical, chemical, and biological processes in the coastal zone of Lake Superior where both vertical and horizontal thermal structure and transport processes are important. The research team is divided into three subgroups: Physical Processes, Chemical Gradients, and Biological Communities. The Physical Processes group will examine the relative importance of all forcing factors (e.g., wind-driven variability, baroclinic instability) that govern cross margin transport using in situ observations, numerical modeling, and satellite observations. The Chemical Gradients group will characterize nearshore-offshore differences in distributions of chemical species, evaluate chemical tracers of wa ter and sediment movement, and investigate differences (inshore vs. offshore) in chemical cycles induced by the current. The Biological Communities group will determine how gradients in primary production, trophic structure, and rates of material transformation develop. All three groups will interact closely throughout the project to obtain and share complementary data sets and to derive a coupled physical/chemical/biological model of the system. The detailed, process-level understanding achieved by this project will advance our quantitative understanding of the processes that regulate the transport, transformation and fate of biologically, chemically and geologically important matter in coastal regions and provide a firm basis for future management decisions on how best to preserve the pristine nature of Lake Superior. Under this award, moorings will be deployed through three full years so that conditions in all seasons, including under the ice, can be monitored. Ground-based measurements will be enhanced by concurrent satellite determination of surface temperature and archived images will be employed to obtain a record of interannual variability in thermal structure. Work will also lead to development of chemical tracers of water and sediment movement by fingerprinting particles originating within the study zone in order to track and quantify present-day and historic patterns of particle transport from nearshore to offshore. Measurement of radionuclides on particles within the nearshore zone and in cores from the offshore zone will play a critical role in identification of sediment transport and deposition pathways.

小行星9712871 研究将根据机会公告（NSF 97-38）进行， 五大湖的海岸研究。 这是一个合作研究项目， 来自五个学术研究机构的研究人员。 这项研究是根据 美国国家科学基金会沿海海洋过程（CoOP）计划和美国国家海洋和大气管理局沿海海洋 程序. 这个合作，跨学科的5年研究计划将需要一个综合的 一项实地和实验室研究以及数学建模的计划，以量化沿海地区的作用 电流和热锋介导跨边缘运输在苏必利尔湖上级。 苏必利尔湖上级的基威诺半岛的西海岸展示了一个戏剧性的沿海急流， 基维诺洋流 一个强大的，平行于海岸的密度锋，热棒，也是 这是该地区的特点，并持续到夏天很长时间。拟议工作的目标是 确定由强烈的物理强迫引起的物理、化学和生物效应 在这个系统上，特别是，阐明这些影响如何在时间和空间上相互作用， 定义了苏必利尔湖上级不同的近岸和近海环境。 该项目代表了 第一次尝试在沿海地区模拟耦合的物理，化学和生物过程， 上级湖的垂直和水平热结构和运输过程都是 重要. 研究小组分为三个小组：物理过程，化学过程， 生物社区。 物理过程组将检查所有的相对重要性 强制因素（例如，风驱动的变率，斜压不稳定），控制横向边缘 运输使用现场观测，数值模拟和卫星观测。 化学 化学物质组将描述化学物质分布的近岸-近海差异， 物种，评估水和沉积物运动的化学示踪剂，并调查差异 （近岸与离岸）在化学循环引起的电流。 生物群落 研究小组将确定初级生产、营养结构和物质速率的梯度 转型发展。所有三个小组将在整个项目中密切互动， 共享互补的数据集，并得出一个耦合的物理/化学/生物模型， 系统 该项目所实现的详细的过程级理解将促进我们的 定量了解调节运输，转化和归宿的过程， 生物，化学和地质重要的物质在沿海地区，并提供了一个坚定的 未来管理决策的基础，如何最好地保护湖泊的原始性质 上级。 根据这项合同，系泊设备将部署整整三年，以便所有条件 季节，包括冰下，可以监测。 将加强地面测量 将利用卫星同步测定地表温度和存档图像 以获得热结构年际变化的记录。工作还将导致 水沙运动化学示踪剂的研制 在研究区域内起源，以跟踪和量化当今和历史的模式， 从近岸到离岸的颗粒输送。测量大气中粒子上的放射性核素 近岸区和近海区的岩心将在识别 沉积物输运和沉积途径。