Collaborative Research: The Influence of the Mediterranean Outflow Water on the Climatic Variability of the North Atlantic

合作研究：地中海流出水对北大西洋气候变化的影响

• 批准号: 0452706
• 负责人: Eric Chassignet
• 金额: $ 67.6万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0452706&HistoricalAwards=false
• 关键词: Collaborative; Research; Influence; Mediterranean; Outflow

ABSTRACTOCE-0452679/0452706Convection in the Mediterranean Sea produces a warm salty water mass that flows over the Gibraltar sill into the Atlantic at mid-depth, forming one of the most pronounced property distributions tongue in the global ocean. The impact of these overflow waters on the dynamics and properties of the North Atlantic basin is disproportionate to its relatively small volume flux. The high salinity contributes to the preconditioning of the surface waters in the Nordic Seas for deep convection, either directly via advection or indirectly via mixing. Additionally, these waters establish the property fields in the eastern North Atlantic over a depth range that considerably exceeds the overflow thickness, and of the entire mid-depth subtropical basin, influence the dynamics of the eastern basin. The variability of the Mediterranean overflow wagters has been largely ignored. A recent study has shown increases in the temperature and salinity over the past fifty years. The two main questions of this study are: what is the spatial and temporal context for these changes, and what is the impact of these changes on the property fields and dynamics of the eastern North Atlantic and on the basin as a whole? To address these questions, data and modeling analyses are proposed to assess not only the consequence of Mediterranean overflow variability on the basin, but also the relative importance of other sources of variability. While past studies have focused on the mesoscale variability created by Meddies, our focus will be on interannual and decadal time scales Overall, the salinification of the Mediterranean overflow waters stands in sharp contrast to the observed freshening of high latitude surface waters and of the convective water masses emanating from the northern North Atlantic. If high latitude waters continue to freshen, the bulk of the convective activity that sends heat to the deep ocean may fall to source waters at mid-latitudes, providing added impetus for the study of the Mediterranean overflow waters. Intellectual Merit: This work will determine the source of long-term variability for a water mass that plays an important role for the properties of the eastern North Atlantic, and for the climate of the global ocean. Additionally, the dynamic response of a basin to a temporally varying overflow will be evaluated to establish the spatial and temporal variability of the basin's property fields. Broader Impacts: An improved understanding of the fate of the overflow will illuminate how changes in a marginal sea are transmitted through the open ocean, and will help improive the modeling of overflow waters throughout the global ocean. Finally, this work will train a graduate student in modeling and data analyses.

摘要-0452679/0452706地中海的对流产生了一个温暖的咸水团，它在中层流过直布罗陀岩床进入大西洋，形成了全球海洋中最明显的财产分布舌之一。 这些溢出沃茨对北大西洋海盆的动力学和性质的影响与其相对较小的体积通量不成比例。高盐度有助于预处理的表面沃茨在北欧海的深对流，直接通过平流或间接通过混合。 此外，这些沃茨在北大西洋东部的深度范围内建立了财产领域，大大超过了溢出厚度，以及整个中深度亚热带盆地，影响东部盆地的动态。 地中海溢流船的可变性在很大程度上被忽视了。 最近的一项研究表明，在过去的50年里，温度和盐度都在上升。 本研究的两个主要问题是：这些变化的空间和时间背景是什么，以及这些变化对北大西洋东部和整个海盆的属性场和动态的影响是什么？ 为了解决这些问题，数据和建模分析，提出了评估不仅地中海溢出的变化对流域的后果，但也相对重要性的其他来源的变化。 虽然过去的研究都集中在中尺度的变化所创建的Meddies，我们的重点将是年际和十年的时间尺度总体而言，地中海溢出沃茨的盐化站在鲜明的对比，所观察到的清新高纬度表面沃茨和对流水团从北大西洋北方。 如果高纬度沃茨继续变新鲜，那么向深海输送热量的大部分对流活动可能会落到中纬度的源头沃茨，从而为研究地中海溢出沃茨提供更多的动力。 智力优势：这项工作将确定水团长期变化的来源，水团对北大西洋东部的性质和全球海洋的气候起着重要作用。 此外，将评估流域对随时间变化的溢流的动态响应，以确定流域属性场的空间和时间变化。 更广泛的影响： 更好地了解溢出的命运将阐明边缘海的变化是如何通过公海传播的，并将有助于改善全球海洋溢出沃茨的建模。 最后，这项工作将培养一个研究生在建模和数据分析。