Collaborative Research: Long-term Observations in the Switchyard Region of the Arctic Ocean as part of the Arctic Observing Network (AON)

知识价值：该奖项支持在加拿大埃尔斯米尔岛（Ellesmere Island）北部和格陵兰岛（Greenland）的“开关站”（Switchyard）进行为期三年的海洋观测，这里的水经Fram和Nares海峡从北冰洋向南流出。“开关站”观测工作是美国国家科学基金会北极观测网络（AON）的一部分，该网络支持长期、科学驱动的观测，使研究能够了解北极环境系统的快速变化。AON是更广泛的北极环境变化研究（SEARCH）的组成部分。“切换站”观测的关键要素是：(1)在Alert和北极之间使用CTD-O/ rossette系统进行基于飞机的剖面，使用一组示踪剂/碳系统变量，旨在通过CFC和氚/氦-3测量来解决相对年龄结构，并通过上层水柱中的氧-18和钡测量来解决淡水成分；(2)基于飞机的林肯海水文/示踪/碳测量，旨在捕捉区域淡水路线的变化，以及边界流和穿越“转换场”区域的跨极漂移之间的前沿；(3)完成横跨纳尔斯海峡以西大陆架斜坡的8个系泊阵列，旨在捕捉围绕加拿大盆地流向纳尔斯海峡和弗拉姆海峡的水团的结构和运输。该奖项的成功完成将使“开关站”观测记录延长至10年，这将使研究人员能够提高对以下方面的认识：(1)水团特征及其对分层、底波热通量和热盐输送的影响；(2)淡水储量（包括以海冰形式储存的储量）；(3)向北大西洋释放淡水；(4)上层水层热收支及其与海冰覆盖的相互作用；(5)海冰环流和厚度分布；(6)未来的循环模式。更广泛的影响：北极正在过渡到一个更温暖的世界，在“调关站”中获得的数据将提供北极环境系统如何对人为强迫作出反应的早期迹象。通过项目网站和北极合作数据和信息服务中心（AON数据存储库），这些数据可以免费公开地提供给更广泛的科学界。与其他NSF AON项目和国际项目的合作有助于协调和整合AON和SEARCH的科学驱动的海洋和海冰观测部分。该项目通过本科生和研究生积极参与西雅图太平洋科学中心的极地科学周末活动，促进教育和推广，激励新一代科学家和工程师。

Intellectual merit: This award supports a further three years of ocean observations in the 'Switchyard', the area north of Ellesmere Island, Canada, and Greenland, where water flows south out of the Arctic Ocean via Fram and Nares straits. The 'Switchyard' observing effort is part of the NSF Arctic Observing Network (AON), which supports long-term, science-driven observing that enables research into understanding rapid environmental system change in the Arctic. AON is a component of the broader Study of Environmental Arctic Change (SEARCH). The key elements of the 'Switchyard' observations are: (1) an aircraft-based section using a CTD-O/rosette system between Alert and the North Pole of hydrographic properties and a set of tracers/carbon system variables aimed at resolving the relative age structure via CFC and tritium/helium-3 measurements and freshwater components via oxygen-18 and barium measurements in the upper water column; (2) an aircraft-based hydrography/tracer/carbon survey of the Lincoln Sea aimed at capturing changes in the regional freshwater routing and the front between the boundary current and the transpolar drift passing through the 'Switchyard' region; and (3) completion of an 8-mooring array across the shelf slope just west of Nares Strait aimed at capturing the structure and transport of the water masses coming around the Canada Basin on their way to Nares and Fram straits. Successful completion of the award will extend the 'Switchyard' observational record to 10 years, which will allow researchers to improve the understanding of the following: (1) water mass characteristics and their effect on stratification, diapycnal heat fluxes, and transport of heat and salt; (2) freshwater inventories (including that stored in form of sea ice); (3) freshwater release to the North Atlantic Ocean; (4) heat budget of the upper water layers and its interplay with the sea ice cover; (5) sea ice circulation and thickness distribution; and (6) future circulation patterns. Broader Impacts: The Arctic is undergoing a transition into a warmer world, and the data obtained in the 'Switchyard' will provide early indications of how the Arctic environmental system is responding to anthropogenic forcing. The data are freely and openly available to the broader scientific community via project Web sites and at CADIS (Cooperative Arctic Data and Information Service), the AON data repository. Collaboration with other NSF AON projects and international projects contributes to coordination and integration of a science-driven ocean and sea ice observing component of AON and SEARCH. The project contributes to education and outreach to inspire a new generation of scientist and engineers via undergraduate and graduate student participation and active involvement in the Polar Science Weekend at the Pacific Science Center, Seattle.