The shallow limb of the Atlantic meridional overturning circulation: variability and impacts on the ocean's carbon and nutrient reservoirs

大西洋经向翻转环流的浅层：变化及其对海洋碳和营养物库的影响

• 批准号: 402312-2011
• 负责人: Palter, Jaime
• 金额: $ 0.9万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=573238
• 关键词: shallow; limb; Atlantic; meridional; overturning

The subpolar North Atlantic is a region where intense air-sea interactions cause the transformation of thermocline waters into of a collection of water masses known as North Atlantic Deep Water (NADW). The NADW floods the deep and intermediate depths of the basin and provides a pathway for global change to find its oceanic expression. The precursor waters that are transformed to become NADW stem partly from subtropical water masses, whose penetration into the subpolar gyre is thought to vary temporally. The basic mechanisms that govern the overturning transport and its temporal variability remain poorly understood, as do the implications for the ocean's interior heat, carbon, and nutrient reservoirs. In order to detect anthropogenic change in the ocean's circulation and biogeochemical properties, we must enhance our understanding of the mechanisms causing this variability. Therefore, the fundamental questions to be addressed by the proposed work are: What are the dominant mechanisms setting the temporal variability of the Atlantic overturning transport? What are the consequences of such variability on the biogeochemical properties of the NADW? The work will be organized around 3 objectives: 1. Characterize mechanisms governing variability in the MOC, its vulnerability to anthropogenic change, and its impacts on the ocean's carbon and nutrient reservoirs in a General Circulation model. 2. Investigate the variability and trends emerging in observational data from hydrographic missions, satellite products, and nearly two decades of data collected by profiling floats in the North Atlantic. 3. Build a program at McGill that will collect direct observations of the shallow limb of the Atlantic overturning circulation. This goal includes the mounting of a lab for the autonomous collection of observations in the harsh ocean environments in which water masses are formed.

在北大西洋副极地地区，强烈的海气相互作用导致温跃层水域转变为被称为北大西洋深水（NADW）的水团集合。 NADW淹没了盆地的深层和中层深度，并为全球变化寻找其海洋表现提供了途径。 转变为 NADW 的前驱水部分源自副热带水团，人们认为副热带水团对副极地环流的渗透会随时间变化。 控制翻转运输及其时间变化的基本机制仍然知之甚少，对海洋内部热量、碳和营养物库的影响也是如此。为了检测海洋环流和生物地球化学特性的人为变化，我们必须加强对造成这种变化的机制的理解。 因此，拟议工作要解决的基本问题是：决定大西洋翻转运输时间变化的主导机制是什么？ 这种变化对 NADW 的生物地球化学特性有何影响？ 这项工作将围绕 3 个目标进行： 1. 描述控制 MOC 变化的机制、其对人为变化的脆弱性及其对大气环流模型中海洋碳和营养物库的影响。 2. 调查来自水文测量任务、卫星产品的观测数据以及北大西洋剖面浮标收集的近二十年数据的变化和趋势。 3. 在麦吉尔建立一个项目，收集大西洋翻转环流浅层的直接观测结果。 这一目标包括建立一个实验室，用于在形成水团的恶劣海洋环境中自主收集观测数据。