Collaborative Research: The Influence of the Mendeleev Ridge and Chukchi Borderland on the Large-scale Circulation of the Arctic Ocean

合作研究：门捷列夫海岭和楚科奇边境对北冰洋大范围环流的影响

• 批准号: 0117480
• 负责人: Rebecca Woodgate
• 金额: $ 41.93万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-01-01 至 2006-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0117480&HistoricalAwards=false
• 关键词: Collaborative; Research; Influence; Mendeleev; Ridge; Collaborative; Research; Influence; Mendeleev; Ridge

The most important subsurface Arctic Ocean transport system, a cyclonic (here anticlockwise) boundary current, organized along the continental slopes and major trans-Arctic ridges, distributes waters, tracers and contaminants from the Atlantic (via Fram Strait and the Barents Sea) and the Pacific (via Bering Strait) around and into the deep Arctic basins. On its circum-Arctic pathway, parts of the topographically steered current are diverted away from the continental margin, generally along topographic ridges. The most complex obstacle the boundary current encounters is the Mendeleev Ridge/Chukchi Borderland complex, north of the Pacific entrance to the Arctic. This region is the cross- roads for Pacific-origin waters from the south and Atlantic waters carried from the west with the boundary current. The tortuous bathymetry offers many routes for a topographically steered current, and the spatial variability of the sparse data that exist clearly indicates the complexity of the region. These data also show significant interannual variability, in line with the major changes seen in the last decade throughout the Arctic, and they further suggest that the region diverts significant amounts of water into the deep basins, indicating this region's importance to shelf-basin exchange, deep basin ventilation, and circum- and trans-Arctic circulation (with feedback implications to the World Ocean circulation). Yet, the pathways and exchanges in this area are still unclear, both qualitatively and quantitatively, due to the lack of sufficiently concentrated observations. This research will conduct a high spatial resolution hydrographic and tracer survey, supported by short-term moored current and CTD measurements, in the region of the Chukchi Borderland and the southern end of the Mendeleev Ridge during August/September 2002.The objectives are to:- delineate the pathways of the boundary current carrying the Atlantic water past the Mendeleev Ridge and through the Chukchi Borderland;- ascertain the input from the boundary current and the shelves to the deep Arctic Ocean in the vicinity of the Mendeleev Ridge and the Chukchi Borderland;- understand and quantify the pathways and transformations of the Pacific waters through this region;- describe the horizontal and vertical structure of the boundary current, and estimate its transport; and- quantify recent temporal changes in this region by combining the spatially sparse data extending through most of the past decade with new detailed synoptic measurements.On a 35-day expedition on an ice-breaking research vessel, measurements will be made of temperature, salinity, dissolved oxygen, nutrients, CFCs, Ba, and 18-O on 12 sections that cross both the boundary flow and the Pacific inputs to the region before and after topographic junctions and hypothesized regions of flow diversion. This tracer suite will enable identification of the pathways of the boundary current and the Pacific-origin waters, and quantification of the different Atlantic and Pacific influences, as well as freshwater input from ice melt and different rivers. In addition, three moorings will be deployed, spanning the boundary current for the duration of the cruise. Current meters and moored conductivity and temperature sensors will quantify the vertical and horizontal extent of the boundary current, its structure and variability, and will yield an estimate of the transport and a description of eddies carried with or across the boundary current. To give a comprehensive picture of the system, the entire data set will be analyzed collectively and in tandem with hydrographic, tracer, and moored time series data from the last decade. Since the transit time of signals through this region is 2-4 years, the older data provide a temporal background for the new high spatial resolution data, whilst the newer data will supply an essential spatialframework for understanding the variability of the older surveys.The work will yield a substantially increased understanding of the role of this region in the Arctic circulation, including a determination of pathways, a quantification of exchanges, and an assessment of temporal change. Its timing in 2002 will fill a pending hiatus in hydrographic surveys in the Canadian Basin at a time when the most dramatic changes ever observed in the Arctic are propagating through this region. The project will provide necessary background and mechanistic information to the potential SEARCH and Arctic-Subarctic Ocean Flux programs, and essential far-field information to the SBI Phase II field program in the Chukchi and Beaufort seas. In addition, the results will be pivotal to validating and improving high resolution computer and conceptual models of the Arctic, and will offer insights to physical mechanistic problems, such as the driving mechanism of the boundary current and the interaction of an equivalent barotropic current with steep and sharp topography.

最重要的地下北极海洋传输系统是一种沿大陆斜率和主要的跨北极脊而组织的气旋（此处逆时针）边界电流，它分布了来自大西洋（通过Fram Strait and Barents和Barents Sea）以及周围和深度深处基础的水域（通过Fram Strait and Barents Sea）（通过Fram Strait和Barents Sea）（通过Fram Strait and Barents Sea）分布水域，示踪剂和污染物。在北极路径上，地形转向电流的一部分被转移到大陆边缘，通常沿着地形脊。边界电流遇到的最复杂的障碍是Mendeleev Ridge/Chukchi Borderland Complex，位于北极太平洋入口以北。该地区是从西部和西部的大西洋水域的太平洋水域的跨道路，并带有边界电流。曲折的测深量法提供了许多途径，可用于地形转向电流，而存在的稀疏数据的空间可变性清楚地表明了该地区的复杂性。这些数据还显示出显着的年际变化，这与在整个北极的过去十年中所看到的重大变化一致，它们进一步表明该地区将大量的水转移到了深层盆地中，表明该地区对货架 - 基础交换，深层盆地通风，以及绕过盆地的循环和反式摩擦循环的重要性（以及对世界海洋循环的反馈）。然而，由于缺乏足够浓缩的观测值，在定性和定量上，该领域的途径和交流仍不清楚。 This research will conduct a high spatial resolution hydrographic and tracer survey, supported by short-term moored current and CTD measurements, in the region of the Chukchi Borderland and the southern end of the Mendeleev Ridge during August/September 2002.The objectives are to:- delineate the pathways of the boundary current carrying the Atlantic water past the Mendeleev Ridge and through the Chukchi Borderland;- ascertain the input from the边界电流和架子到Mendeleev Ridge和Chukchi Borderland附近的深北极海洋；并通过将过去十年中大部分范围的空间稀疏数据与新的详细的杂音测量结合结合来量化该区域的最新时间变化。在破冰研究船上进行了35天的探险，将对温度，盐度，盐度，溶解的含量，营养素，CFCS，BA和Pac pac和12 Sections and Incorts and Incorts and Incorts and Incort and Incort the 12 Sections进行测量。地形连接和假设的流动区域。该示踪剂套件将能够鉴定边界电流和太平洋 - 原始水域的途径，对不同大西洋和太平洋影响的定量，以及冰融化和不同河流的淡水输入。此外，将部署三个系泊设备，跨越巡航时间的边界电流。电流仪表和系泊电导率和温度传感器将量化边界电流的垂直和水平范围，其结构和可变性，并将得出传输的估计以及对边界电流或边界电流或跨边界电流的涡流的描述。为了全面了解系统，将与过去十年中的水文，示踪剂和停泊的时间序列数据共同分析整个数据集。由于通过该区域的信号的运输时间为2 - 4年，因此较旧的数据为新的高空间分辨率数据提供了一个时间背景，而新的数据将为理解旧调查的可变性提供必不可少的空间框架。该工作将大大增加对北极循环中该区域的作用的理解，包括临时循环的确定，并确定了一定的量化量化和量化的确定。在2002年的时间安排将在加拿大盆地的水文调查中填补待处理的中断，而在北极中观察到的最大变化正在通过该地区传播。该项目将为潜在的搜索和北极海洋通量计划提供必要的背景和机械信息，并为Chukchi和Beaufort Seas的SBI II期现场计划提供必要的远场信息。此外，结果将对验证和改善北极的高分辨率计算机和概念模型至关重要，并将为物理机械问题提供见解，例如边界电流的驱动机理以及与陡峭和尖锐的外形相同的正压电流的相互作用。