Line W: A Sustained Measurement Program Sampling the North Atlantic Deep Western Boundary Current and Gulf Stream at 39oN

W 线：对北大西洋深西边界流和北纬 39 度墨西哥湾流进行采样的持续测量计划

• 批准号: 0726720
• 负责人: John Toole
• 金额: $ 555万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0726720&HistoricalAwards=false
• 关键词: Line; Sustained; Measurement; Program; Sampling

The meridional overturning circulation of the North Atlantic Ocean at mid-latitude principally involves poleward transport of warm water by the Gulf Stream and equatorward flow of colder intermediate and deep waters within a western-intensified boundary current. Comprehension of how these limbs of the global current system and their associated regional recirculations vary on decadal time scale is incomplete. In particular, very little is known on how inter-annual variations in air-sea exchange and water mass modification at high latitudes are transmitted equatorward, and what impacts or feedbacks such signals may have for the Atlantic-wide circulation. Limiting advance in understanding is the lack of long, well-resolved records to document inter-annual signals in water properties, stratification and transport of the Atlantic?s Deep Western Boundary Current (DWBC) system. Importantly, anomalies created at sub-polar latitudes may be profoundly altered or even blocked by the North Atlantic Current or Gulf Stream. Conversely, sub-polar anomalies may influence the position, strength, and/or stability of the Stream, and in turn affect patterns of air-sea exchange throughout the North Atlantic. These basic questions motivate the Line W program that is presently returning observations of the DWBC and Gulf Stream about 39 N between the Grand Banks and Cape Hatteras. Companion field programs are sampling the DWBC both north and south of our study region, and several complementary modeling programs are underway. Taken together, these studies will facilitate a comprehensive investigation of the mechanisms and rates of North Atlantic Deep Water export to lower latitudes and its relationships to the upper ocean circulation.Intellectual Merit: The proposed study will build understanding of the mechanisms and rates of North Atlantic Deep Water export to lower latitudes and the relationships of varying deep-water flow and stratification changes to the upper ocean circulation including the Gulf Stream. This knowledge will help clarify the response of the ocean to variations in air-sea exchange and ultimately, the ocean's role in global climate change. This project will extend the on-going observations of temperature, salinity, tracer and velocity variations of the DWBC and Gulf Stream through 2013, yielding a full 10-year record synchronous with the planned U.K.-U.S. observational program at 26 N. The Line W program consists of a moored array over the continental slope south of Woods Hole, and repeated occupations of a hydrographic section along the array and extending south into the Sargasso Sea. The high spatial resolution sampling possible from ship is verifying that the array is spatially resolving the inter-annual signals as well as returning water samples for tracer analysis. Equally important, the investigators will explore whether a subset of current Line W program is sufficient to index water property and transport variations in this area, setting the stage for a long-term ocean observing system. Broader Impacts: The observations proposed will explore and test theoretical ideas about the interaction of the Deep Western Boundary Current and Gulf Stream; this is the focus of a Ph.D. thesis under current Line W funding. MIT/WHOI Joint Program students enrolled in the introductory physical oceanography course will participate on the proposed cruises, introducing them to observational oceanography Moreover, the program will continue to support one Ph. D. student from an under-represented group whose dissertation research will focus on the acquired data. All observations and resulting data products will be made available to the community at the earliest possible time via the internet with the intention of fostering widespread use of these data so that any member of the community can utilize them in their own research program. As data are recovered and processed, the Line W observations are being made available for model validation and study of regional processes by any interested investigators. In addition to raw observations, value-added products such as time series of core properties and transport by water mass are being produced and distributed. Other researchers are also encouraged to build on the Line W infrastructure to augment the physical fields being sampled.This project is a contribution to the U.S. CLIVAR (CLImate VARiability and predictability) Program.

北大大西洋的子午倾斜循环主要涉及在西方强化边界电流内通过海湾流和冷水中的赤道流和较冷的中间和深水的赤道流动。理解全球当前系统及其相关区域循环的肢体如何在衰老时间范围内有所不同。特别是，关于高纬度地区空气交换和水质量修饰的年度变化几乎没有人知道，并且这种信号对大西洋循环的影响或反馈可能产生什么影响或反馈。限制了理解的限制是缺乏长期，完善的记录来记录大西洋深西边界电流（DWBC）系统的水性质，分层和运输中的年度信号。重要的是，在亚极纬度上产生的异常可能会被北大西洋电流或墨西哥湾流深刻改变甚至阻塞。相反，亚极性异常可能会影响溪流的位置，强度和/或稳定性，进而影响整个北大西洋的空气交换模式。这些基本问题激发了线路W计划，该计划目前正在返回对大银行和哈特拉斯角之间约39 n的DWBC和墨西哥湾流的观察结果。伴侣现场计划正在我们研究地区的北部和南部进行DWBC，并正在进行一些互补的建模计划。综上所述，这些研究将促进对北大西洋深水导出到较低纬度的机制和速率的全面研究，及其与上海循环的关系。Intlectual-Ferior：拟议的研究将建立对北大西洋深水导出的机制和速率的理解，以降低水流的较低水平以及高级循环的循环，包括较低的循环循环。这些知识将有助于阐明海洋对空气交换的变化以及海洋在全球气候变化中的作用的反应。该项目将把DWBC和Gulf流的温度，盐度，示踪剂和速度变化的持续观察到2013年，从而与计划的英国 - U.S.同步了完整的10年记录同步。第26号的观察计划。线W程序由伍兹孔以南的大陆斜坡上的停泊阵列组成，并重复沿阵列的水文部分，并向南延伸至Sargasso Sea。从船上进行的高空间分辨率采样是在验证阵列是否正在空间解析年间信号以及返回水样品进行示踪剂分析。同样重要的是，研究人员将探讨当前线W计划的子集是否足以将水财产和运输变化索引，为长期海洋观察系统奠定了基础。 更广泛的影响：提出的观察将探索和测试有关深西边界电流和海湾流相互作用的理论思想；这是博士学位的重点。在当前行w资助下的论文。参加入门物理海洋学课程的麻省理工学院/WHOI联合计划学生将参加拟议的巡航，并将其介绍给观察性海洋学，此外，该计划将继续支持来自一个不足代表的小组的一位学生，其学位论文研究将集中在被收购的数据上。所有观察结果和最终的数据产品将尽早通过互联网提供给社区，以促进这些数据的广泛使用，以便社区的任何成员都可以在自己的研究计划中利用它们。随着数据的恢复和处理，任何感兴趣的研究人员都可以通过对模型验证和研究区域流程进行研究。除了原始观察结果外，还生产和分布了核心特性的增值产品，例如核心特性的时间序列和水量运输。还鼓励其他研究人员建立在基础架构的线路上，以增强被采样的物理领域。该项目是对美国Clivar（气候可变性和可预测性）计划的贡献。