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

大西洋和太平洋都有赤道潜流，这是一种位于赤道附近的向东的强流。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和东部边界附近的赤道外上升流穹顶提供温跃层水。在太平洋，这股潮流从十多年来密集的船上和时间序列项目中得到了很好的描述。赤道潜流的变化在季节和年际时间尺度上都与东部冷舌区的海面温度变化密切相关，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，它在整个盆地的平均结构和它的季节到年际变化并没有被很好地理解。特别是在盆地东部，赤道潜流在那里衰减，似乎在向东穿透时表现出很强的可变性，观测结果很少，几乎没有时间序列测量数据。在这项研究中，迈阿密大学的科学家将通过使用ADCP进行为期三年的系泊海流观测，研究大西洋东部海流的季节变化和年际变化。根据这些数据，它们将描述大西洋中部和东部的平均状态和变化，包括洋流进入几内亚湾的距离。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。这项研究还将极大地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率的理解。这种变化会影响整个地区的气候。他们的研究为热带大西洋气候实验(TACE)的目标做出了贡献，TACE是一个旨在改善气候预测的CLIVAR计划。

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.