Collaborative Research: The Norrona Project: An International Collaboration for Sustained Studies of the Meridional Overturning Circulation between Denmark, the Faroes and Iceland

合作研究：诺罗纳项目：丹麦、法罗群岛和冰岛之间经向翻转环流持续研究的国际合作

• 批准号: 1061185
• 负责人: H. Thomas Rossby
• 金额: $ 60.04万
• 依托单位: University of Rhode Island
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1061185&HistoricalAwards=false
• 关键词: Collaborative; Research; Norrona; Project; International

The Atlantic/meridional overturning circulation (A/MOC) has been the focus of growing attention in recent years. Much of this arises from the widespread recognition that the flow of warm, salty water to high latitudes - the Nordic Seas - helps shape the mild climate experienced across central and northern Europe and no doubt influences climate across the northern hemisphere. Thus the strength and stability of the MOC is a key parameter in the climate puzzle and therefore of great societal relevance. For this reason a project was funded in 2005 to monitor the inflow of warm water into the Nordic Seas across the Iceland-Faroe- Scotland ridge, a natural choke point through which virtually all north-flowing water must pass. What made the undertaking so attractive was the existence of an ocean-going ferry, the Norröna, from which current measurements using a vessel-mounted acoustic Doppler current meter (ADCP) could be made. The Norröna operates weekly across the Faroe-Shetland Channel and along the Iceland-Faroe ridge, the two major inflows. Some unexpected, but very serious start-up problems (bubble drawdown that blocks the acoustics) delayed the project by two years. The company that owns the ferry has gone out of its way to be helpful and substantial amounts of data are now being collected. The original four-year grant received a one-year add-on last year. This award is to continue and strengthen the project for an additional 4 years. First, although the bubble problem has been ameliorated thanks to a fairing and two vortex generators that bring clear water up from below, more can and should be done. Specifically, with the help of numerical calculations in collaboration with the ship designer in September an area free of bubbles will be sought, perhaps closer to the bow. Second, using an underwater camera will be used to verify the performance and wake structure of the vortex generators. Norröna is scheduled for dry-dock this coming winter-spring at which time the final adjustments will be implemented and should lead to substantially improved performance. The unanticipated problem of bubbles under the Norröna has been an extremely valuable learning process regarding the use and placement of ADCPs on commercial vessels. Second, thanks to the recent development of a new automated XBT launcher, heat fluxes can also be measured directly by combining the ADCP and XBT data. Third, the team will begin to report new findings about tidal signals, EKE activity, and inflows. Scientifically, the biggest surprise by far has been the substantial flow (to the south) on the western side of the Faroe-Shetland Channel such that the net flow through the channel appears to be to the south.Intellectual Merit: The Iceland-Faroe-Scotland ridge separates two large and distinctly different water mass systems (the North Atlantic and the Arctic Mediterranean). The exchange between the two is driven by both winds and buoyancy forcing over a wide range of scales. By monitoring the inflows and outflows (thanks to sustained moored ADCP programs) one can examine in considerable detail the space-time response of these fluxes to time-varying atmospheric forcing including the well-known North-Atlantic Oscillation.Broader Impacts: This team has developed extensive expertise with vessel-operated ADCPs. Repeat ADCP enables one to measure currents and transports in the ocean at high horizontal resolution and great confidence. Measuring currents directly adds to dynamical methods that use hydrography or altimetry. High horizontal resolution means resolving the most energetic scales in the ocean - often defined by the radius of deformation. We hope that wider knowledge and use of this technology will, in time, lead to an improved knowledge of ocean currents over a wide range of space and time scales.

近年来，大西洋/经向翻转环流（A/MOC）已成为人们日益关注的焦点，这在很大程度上是因为人们普遍认识到，温暖的咸水流向高纬度地区（北欧海洋）有助于形成温和的气候。中欧和北欧经历的气候无疑会影响整个北半球的气候，因此 MOC 的强度和稳定性是气候难题的关键参数，因此具有重大的社会意义。 2005年，监测跨越冰岛-法罗-苏格兰海岭流入北欧海域的温水，该海脊是一个天然的咽喉点，几乎所有向北流动的水都必须经过该点，这项工作之所以如此有吸引力，是因为存在一条远洋洋流。 Norröna 渡轮可以使用船上安装的声学多普勒海流计 (ADCP) 进行水流测量，Norröna 每周横跨法罗-设得兰海峡和冰岛-法罗海脊。两次主要资金流入。一些意想不到的但非常严重的启动问题（气泡下降阻碍了声学效果）使该项目延迟了两年，拥有渡轮的公司已经竭尽全力提供帮助并提供大量数据。最初的四年期赠款去年获得了一年的附加资助，该奖项将继续并加强该项目的额外四年，尽管由于整流罩的存在，泡沫问题得到了改善。和两个漩涡具体来说，在九月与船舶设计师合作的数值计算的帮助下，将寻找一个没有气泡的区域，也许更靠近船头。水下摄像机将用于验证涡流发生器的性能和尾流结构，计划于今年冬春季进入干船坞，届时将进行最终调整，并应能大幅改善性能。下有气泡Norröna 是关于在商船上使用和放置 ADCP 的一个非常有价值的学习过程。 其次，由于最近开发了新型自动化 XBT 发射器，热通量也可以通过结合 ADCP 和 XBT 数据来直接测量。 ，该团队将开始报告有关潮汐信号、EKE 活动和流入量的新发现。 从科学上讲，迄今为止最大的惊喜是法罗-设得兰海峡西侧的大量水流（向南），使得智力优点：冰岛-法罗-苏格兰海岭分隔了两个巨大且截然不同的水团系统（北大西洋和北冰洋地中海）。两者之间的交换是由两者的出现驱动的。通过监测流入和流出（得益于持续的停泊 ADCP 计划），人们可以相当详细地检查这些通量对时变的时空响应。大气强迫，包括著名的北大西洋涛动。更广泛的影响：该团队在船舶操作 ADCP 方面积累了丰富的专业知识，使人们能够以高水平分辨率和极大的信心直接测量海洋中的洋流和输送。增加使用水文学或高度测量的动力学方法意味着解决海洋中最具活力的尺度——通常由变形半径定义。我们希望这项技术能够得到更广泛的了解和使用。时间，从而提高对广泛的空间和时间尺度上的洋流的了解。