Variability of the Equatorial undercurrent in the eastern tropical Atlantic: Analysis of the 2007-2011 TACE-EUC Experiment

热带大西洋东部赤道暗流的变化：2007-2011年TACE-EUC实验分析

• 批准号: 1129874
• 负责人: William Johns
• 金额: $ 47.1万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1129874&HistoricalAwards=false
• 关键词: Variability; Equatorial; undercurrent; eastern; tropical

The Equatorial Undercurrent (EUC) is a quasi-permanent feature of the zonal equatorial circulation in both the Atlantic and Pacific oceans. Its main role in both oceans is to supply thermocline waters from the shallow subduction zones in the subtropics to the main upwelling zones in the central and eastern part of the equatorial basins. While in the Pacific Ocean the EUC is rather well-described from nearly two decades of intensive shipboard and time-series observations in the tropical Ocean Atmosphere programs, the EUC in the Atlantic has until recently been relatively poorly sampled and neither its mean structure across the basin or its seasonal-to-interannual variability is understood. Its linkage to warm and cold phases of the boreal summer equatorial cold tongue is also poorly understood. During 2007-2011, a coordinated set of moored current meter observations has been collected across the central and eastern equatorial Atlantic during 2007-2011 by German, French, and U.S. investigators. These observations contribute to the goals of TACE (the Tropical Atlantic Climate Experiment), a 2007-2012 international CLIVAR program designed to improve climate predictions for the tropical Atlantic region, with a particular focus on the eastern equatorial Atlantic. The U.S. part of this effort consisted of moored ADCP current profile measurements at four sites along 10W and 0E, complementing a French (PIRATA) ADCP mooring at 10W, and an array of moorings along 23W maintained by IFM-GEOMAR (Germany). This project will complete the analysis of the data collected in this program, following the original NSF grant that supported the U.S. measurements. Intellectual Merit:The variability of the EUC across the basin, its linkages to wind forcing and SST variability, and the nature of the intraseasonal variability along the equator will be documented. The data will be used together with models to understand the dynamics controlling the EUC variability and the fate of EUC waters in the eastern Gulf of Guinea. The results of this analysis are expected to lead to a vastly improved understanding of the EUC in the Atlantic.Broader Impacts:The data collected from the TACE program, including all moored time series and cruise data, is being assembled into a web-accessible database maintained by the TACE Observations Working Group (http://tace.ifm-geomar.de/index.html), to provide ready access to the broader research community. The program has also provided graduate student training opportunities and promoted collaboration and sharing of technical expertise among international partners. The study will also contribute to an improved understanding of processes influencing SST variability in the eastern tropical Atlantic and associated climate variability in the tropical Atlantic region.

赤道潜流是大西洋和太平洋纬向赤道环流的一种准永久性特征。它在这两个大洋的主要作用是从亚热带的浅俯冲带向赤道盆地中部和东部的主要上升流带供应温跃层水。在太平洋，近20年来对热带海洋大气方案进行了密集的船上观测和时间序列观测，可以很好地描述太平洋的海温变化，但直到最近，对大西洋的海温变化的采样都相对较差，既不了解它在整个盆地的平均结构，也不了解它的季节-年际变化。它与北半球夏季赤道冷舌的冷暖阶段之间的联系也鲜为人知。2007-2011年，德国、法国和美国的调查人员在赤道大西洋中部和东部收集了一组协调一致的系泊海流计观测数据。这些观测结果有助于实现TACE(热带大西洋气候实验)的目标，这是一项2007-2012年的国际CLIVAR计划，旨在改善热带大西洋地区的气候预测，特别是赤道东部大西洋的气候预测。这项工作的美国部分包括在10W和0E沿线的四个站点进行系泊ADCP海流剖面测量，补充由IFM-GEOMAR(德国)维护的法国(Pirata)10W系泊ADCP和23W沿线系泊的一系列系泊。该项目将完成对该计划中收集的数据的分析，遵循支持美国测量的原始NSF拨款。知识价值：将记录整个流域的EUC的可变性，它与风强迫和海温可变性的联系，以及赤道地区季节内可变性的性质。这些数据将与模型一起使用，以了解控制EUC变异性的动态以及几内亚湾东部EUC水域的命运。这一分析的结果有望极大地改善对大西洋欧洲宇宙空间委员会的了解。广泛的影响：从大西洋宇航中心项目收集的数据，包括所有系泊的时间序列和巡航数据，正在被汇编到一个由大西洋宇航中心观测工作组(http://tace.ifm-geomar.de/index.html)，)维护的可上网数据库中，以提供对更广泛的研究社区的随时访问。该方案还提供了研究生培训机会，并促进了国际合作伙伴之间的合作和技术专长的分享。这项研究还将有助于更好地了解影响热带大西洋东部海温变率和热带大西洋区域相关气候变率的过程。