Collaborative Research: Shelf-Basin Exchange South of Denmark Strait: Forcing, Dynamics, and Large-Scale Impact

合作研究：丹麦海峡以南的陆架盆地交换：强迫、动力学和大规模影响

• 批准号: 0726393
• 负责人: Thomas Haine
• 金额: $ 38.68万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0726393&HistoricalAwards=false
• 关键词: Collaborative; Research; Shelf; Basin; Exchange

The Irminger Sea, situated between southern Greenland and the Reykjanes Ridge, is a critically important area where the Arctic Sea first meets the North Atlantic Ocean. South of the Denmark Strait, a sharp front is formed where cold, fresh outflowing Arctic water meets the warm, salty subtropical-origin water. This front and its associated jet, the East Greenland/Irminger Current, act as the main pathway that recirculating subtropical-origin Arctic water is exported to the North Atlantic. With the stress of the down-front barrier winds adjacent to the Greenland plateau in addition to the instability and time-variability of both the front and the Irminger Current, intense shelf-basin exchange with the open Atlantic occurs in this region. As part of this exchange process, dense shelf water cascades over the shelf-break to form a "Spill Jet" which resides below the East Greenland/Irminger Current. This results in substantial sinking, which occurs downstream in the Labrador Sea and impacts the sub-polar gyre and the meridional overturning circulation to northern freshwater sources. Currently, scientists have a poor understanding of this complex shelf-break current system, and thus are unsure of its transport, freshwater flux, seasonal evolution, and the nature and dynamics of the mesoscale variability that lead to the cross-stream exchange of mass and properties. Through a joint observational/modeling study, oceanographers from Woods Hole Oceanographic Institution and Johns Hopkins University propose to quantify the hydrodynamic instability and atmospheric forcing that drive shelf-basin exchange to occur east of Greenland. By examining the mean and seasonally varying transport, structure, and kinematics of the East Greenland/Irminger Current system and determining the nature and dynamics of the mesoscale variability that leads to shelf-basin exchange, they will be able to explore how the impact of shelf-basin exchange on the sub-polar North Atlantic has changed in the last few decades and how it may evolve in the future. The broader impacts of this study address the concern about the sensitivity of the North Atlantic meridional overturning circulation with respect to northern freshwater sources. Approximately one half of the total Arctic export of freshwater passes east of Greenland and meets the open Atlantic in the proposed study area, therefore understanding the dynamics of the shelf-basin exchange in this region is essential to potentially predict the response of the North Atlantic to future changes in climate. This research includes funding to support educational outreach including activities in a remote location in southern Greenland, as well as science center exhibits in the United States. Funding is also included to support education and training at both the graduate and undergraduate level.

Irminger海位于格陵兰南部和雷克雅内斯山脊之间，是一个至关重要的地区，北极海首先与北大西洋相遇。在丹麦海峡以南，形成了一个锋利的锋，北极水流寒冷，北极水会遇到温暖，咸的亚热带 - 原始水。这款阵线及其相关的喷气机，东格陵兰/irminger电流，充当循环亚热带 - 原始水的主要途径，将其出口到北大西洋。除了前沿高原的压力与格陵兰高原相邻的压力外，前部和irminger电流的不稳定性和时间变化，与开放大西洋的强烈架子 - 巴asin交换发生在该地区。作为此交换过程的一部分，茂密的架子水在货架上铺设层面，形成了位于东格陵兰/irminger电流下方的“溢流喷气机”。这导致大量下沉，这发生在拉布拉多海的下游，并影响了近极的回旋和子午线翻转循环到北部的淡水来源。目前，科学家对这个复杂的货架破裂电流系统的了解不足，因此不确定其运输，淡水通量，季节性进化以及中尺度可变性的性质和动态，从而导致质量和质量的跨流交换特性。通过一项联合观察/建模研究，来自伍兹洞海洋学机构和约翰·霍普金斯大学的海洋学家提出了量化流体动力不稳定性和大气的迫使，以使货架 - 巴辛交换发生在格陵兰以东。通过检查东格陵兰/irminger当前系统的平均和季节性变化的运输，结构和运动学，并确定导致货架 - 巴金交换的中尺度可变性的性质和动态，他们将能够探索货架的影响 - 在过去的几十年中，北大西洋亚北大西洋上的basin交换发生了变化，以及将来的发展方式。这项研究的更广泛的影响解决了人们对北大西洋背景倾覆相对于北方淡水来源的敏感性的关注。大约一半的北极出口淡水通过格陵兰岛以东，并符合拟议的研究区域的开放大西洋，因此了解该地区的货架 - 巴金交换的动态对于预测北大西洋对北大西洋对北大西洋的反应至关重要。气候的未来变化。这项研究包括支持教育外展的资金，包括在格陵兰南部偏远地区的活动以及美国科学中心展览。还包括资金以支持研究生和本科阶段的教育和培训。