The Irminger Sea Boundary Current System and Interior Convection

伊尔明格海是北大西洋西部的一个特别复杂的区域，在那里发生了许多重要的过程。它是北欧海溢出的稠水最终输送的地方，是中间模式水形成的地点，也是起源于北极的淡水从边界流向开阔的大西洋的地方。所有这些都影响着北大西洋亚极地环流，并对全球颠覆的环流产生影响。了解这些过程是如何运作的，以及它们之间的关系，将使我们能够更好地理解北大西洋气候谜题中的一个重要部分。2001-2004年，美国国家科学基金会在伊尔明格海开展了一项实地项目，以记录盆地中部公海对流的发生，并调查从丹麦海峡到格陵兰南端的边界流系统的演变。该试验包括在内陆的系泊电导率/温度/深度剖面仪，以及对边界流系统的高分辨率船上水文/ADCP测量。通过对这些独特数据的初步分析，结合历史测量和海洋学和大气模型的使用，出现了关于这一重要海洋区域的各种新的和重要的想法。这包括导致内部对流的海洋-大气相互作用的新模式，以及迄今未发现的导致陆架-盆地交换的边界流过程。该提案寻求资金，以开展该项目的分析阶段。描述了一系列研究，每一项研究都有自己的假设，这些研究将极大地促进我们对对流和亚极模水形成的理解，以及控制进入北大西洋西部的离岸质量通量和性质的机制和动力学。知识价值：该项目将阐明大气与亚极海相互作用的新的重要手段，以及连接北极和亚北极区域的海岸和陆架破碎流的动态，并有助于规定从陆架到盆地的横向转移。更广泛的影响：这个项目将帮助我们了解伊尔明格海在北大西洋亚极地涡旋的通风、分层和淡水收支中所起的重要作用。这反过来又对全球经向颠覆环流产生重要影响，包括该系统可能对气候变化作出反应的方式。

AbstractOCE-00450658The Irminger Sea a particularly complex area of the western North Atlantic where a host of important processes occur. It is where the final transport of the dense water overflow from the Nordic Seas is established, it is a site of intermediate mode water formation, and it is where freshwater of Arctic origin gets fluxed off the boundary into the open Atlantic. All of these things impact the North Atlantic subpolar gyre, with ramifications for the global overturning circulation. Understanding how each of these processes work, and their relationship to one another, will enable us to better understand an important piece of the North Atlantic climate puzzle. In 2001-2004 an NSF-sponsored field program was carried out in the Irminger Sea to document the occurrence of open-ocean convection in mid-basin, and investigate the evolution of the boundary current system from Denmark Strait to the southern tip of Greenland. The experiment included moored conductivity/temperature/depth profilers in the interior, and high-resolution shipboard hydrographic/ADCP surveys of the boundary current system. From the initial analysis of these unique data , together with historical measurements and the use of oceanographic and atmospheric models, a variety of new and important ideas have emerged with respect to this important area of the ocean. This includes new modes of ocean-atmosphere interaction leading to interior convection, and heretofore undetected boundary current processes leading to shelf-basin exchange. This proposal seeks funds to carry out the analysis phase of this project. A set of studies is described, each with its own hypothesis, that will significantly advance our understanding of convection and subpolar mode water formation, as well as the mechanisms and dynamics governing the offshore flux of mass and properties into the western North Atlantic. Intellectual Merit: New and important means by which the atmosphere interacts with the subpolar ocean will be elucidated in this project, as well as the dynamics of coastal and shelfbreak currents that link the Arctic and sub-Arctic domains and help dictate the lateral transfer of properties from shelf to basin. Broader Impacts: This project will help us understand the important role that the Irminger Sea plays in the ventilation, stratification, and freshwater budget of the North Atlantic subpolar gyre. This in turn has important ramifications for the global meridional overturning circulation, including the manner in which this system might respond to climate change.