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.

ABSTRACTOCE-0452679/0452706地中海的对流产生温暖的咸水团，越过直布罗陀海床流入大西洋中深度，形成全球海洋中最明显的物性分布舌之一。 这些溢流水对北大西洋盆地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。高盐度有助于北欧海表层水的深层对流预处理，直接通过平流或间接通过混合。 此外，这些水域在北大西洋东部建立了远超溢流厚度和整个中深副热带盆地的财产场，影响东部盆地的动态。 地中海溢流的变异性在很大程度上被忽视了。 最近的一项研究表明，过去五十年来温度和盐度有所增加。 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，这些变化对北大西洋东部和整个盆地的财产场和动态有何影响？ 为了解决这些问题，提出了数据和模型分析，不仅要评估地中海溢流变异对流域的影响，还要评估其他变异来源的相对重要性。 虽然过去的研究集中在 Meddies 造成的中尺度变化上，但我们的重点将放在年际和年代际时间尺度上。 总体而言，地中海溢流水域的盐化与观察到的高纬度地表水和对流水的淡水化形成鲜明对比来自北大西洋北部的物质。 如果高纬度水域继续淡水化，向深海输送热量的大部分对流活动可能会落到中纬度地区的源水，从而为地中海溢流水域的研究提供更多动力。 智力价值：这项工作将确定水团长期变化的来源，该水团对北大西洋东部的特性和全球海洋的气候起着重要作用。 此外，还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：更好地了解溢流的命运将阐明边缘海的变化如何通过公海传播，并将有助于改进对整个全球海洋溢流水域的建模。 最后，这项工作将培训一名研究生的建模和数据分析能力。