Variability of the Equatorial Undercurrent in the Eastern Tropical Atlantic and Gulf of Guinea

热带大西洋东部和几内亚湾赤道暗流的变化

• 批准号: 0623552
• 负责人: William Johns
• 金额: $ 170.02万
• 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: 2006
• 资助国家: 美国
• 起止时间: 2006-10-01 至 2012-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0623552&HistoricalAwards=false
• 关键词: Variability; Equatorial; Undercurrent; Eastern; Tropical

ABSTRACTOCE-0623552The Atlantic and Pacific oceans both have an Equatorial Undercurrent, which is a strong eastward current lying near the equator. 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 and the off-equatorial upwelling domes near the Eastern boundary. In the Pacific Ocean, this current is well-described from over a decade of intensive shipboard and time-series programs. The variability of the Equatorial Undercurrent has been closely linked to sea surface temperature variations in the eastern cold tongue region on both seasonal to interannual time scales and thus the system has important consequences for El Nino events. In the Atlantic Ocean, the Equatorial Undercurrent has received much less scientific attention. Consequently, its mean structure across the basin and its seasonal-to-interannual variability is not well understood. Particularly in the eastern part of the basin, where the Equatorial Undercurrent decays and appears to exhibit strong variability in its eastward penetration, observations are sparse and virtually no time series measurements are available. In this study, scientists from the University of Miami will study the seasonal-to-interannual variability of the current in the eastern Atlantic through moored current observations, using ADCPs, for a three year period. With these data, they will provide a description of the mean state and the variability of the current in the central and eastern Atlantic including how far the current penetrates into the Gulf of Guinea. The study will be conducted at the same time as European scientists are also investigating the circulation of the equatorial Atlantic, and thus one of the broader impacts of this study is the international collaboration. The study also will greatly improve our understanding of how oceanic processes affect sea surface temperature variability in the eastern tropical Atlantic. This variability influences the climate throughout the region. They study contributes to the goals of TACE (Tropical Atlantic Climate Experiment), which is a CLIVAR program that is designed to improve climate predictions.

大西洋和太平洋都有一个赤道潜流，它是一个位于赤道附近的强大的向东流动的洋流。 它在两大洋的主要作用是将亚热带浅俯冲带的温跃层沃茨供应给赤道海盆中部和东部的主要上升流带以及东边界附近的离赤道上升流穹丘。在太平洋，这种电流是很好的描述，从十多年的密集船上和时间序列计划。赤道潜流的变化与东部冷舌区的海表温度变化在季节和年际时间尺度上都有密切联系，因此该系统对厄尔尼诺事件具有重要影响。在大西洋，赤道暗流受到的科学关注要少得多。因此，它的平均结构在整个流域和它的季节到年际变化是不太清楚。特别是在盆地的东部，赤道暗流衰减，似乎表现出很强的变化，在其向东渗透，观测稀疏，几乎没有时间序列测量。在这项研究中，来自迈阿密大学的科学家们将使用ADCP，通过三年期的系泊海流观测，研究东大西洋海流的季节性到年际变化。通过这些数据，他们将提供大西洋中部和东部海流的平均状态和变异性的描述，包括海流深入几内亚湾的程度。这项研究将在欧洲科学家也在调查赤道大西洋环流的同时进行，因此这项研究的更广泛影响之一是国际合作。这项研究还将大大提高我们对海洋过程如何影响热带大西洋东部海面温度变化的理解。这种变化影响了整个地区的气候。他们的研究有助于实现TACE（热带大西洋气候实验）的目标，这是一个旨在改善气候预测的CLIVAR计划。