Observations and Analysis of Deep Equatorial Variability in the Atlantic

自首次在印度洋观测到赤道深层喷流以来，已经过去了30多年。在其间的几十年里，在太平洋和大西洋也观察到/推断出了似乎长期存在的纬向深喷流，以及较短周期的变化（最值得注意的是，赤道上的经向运动大约以每月为时间尺度）。分析和数值模拟都被用于研究赤道深部运动的动力学，并提出了一些理论，但没有一个被证明是完全令人满意的。有限的观测妨碍了对大西洋深层变率的基本描述。高垂直分辨率的船舶观测间隔为6个月或更长时间；离散传感器的时间连续系泊时间序列不能解决近赤道运动的高波数特征。这个项目将收集迄今为止最广泛的赤道大西洋深海变化的测量数据。这是一项美国和德国联合进行的关于赤道大西洋深海变化的研究，与德国联邦教育和研究部资助的一项现有的上层海洋系泊测量工作相结合。新的数据将是评估现有的深赤道运动理论（也许会激发新的想法）和验证数值模型的关键。除了科学互动之外，该项目还将促进世卫组织与IFM-GEOMAR人员之间技术系泊程序的共享。系泊剖面仪将由伍兹霍尔海洋研究所和基尔大学莱布尼茨海洋科学研究所（IFM-GEOMAR）的技术人员共同准备，安装在南纬23度、北纬21度和南纬25度之间的5个独立资助的系泊处，并在1.5年的时间内(2009年11月？2011年春季)。联合观测系统（现有的上层海洋系泊ADCP和离散T/S传感器，加上深层系泊剖面仪）将以最低公数返回：从表面到3500米深度的4天间隔16米垂直分辨率速度剖面和通过上层海洋的~10层的T/S信息，在深度增加到~1米垂直分辨率。WHOI和IFM-GEOMAR的调查人员将结合现有的遥感数据和数值模型输出，对获得的数据进行联合处理和分析。这些数据还将与过去研究过赤道深部变化的北美研究人员分享；这些科学家将被邀请为分析工作作出贡献。主要的研究目标是更好地了解赤道大西洋深海变化的动力学以及这些运动对海洋环流的影响。分析的一个重点将是大西洋深西边界流与赤道深喷流之间的关系，特别是大西洋经向翻转环流在半球之间的变化。该研究的更广泛影响将是更好地理解对气候动力学重要的过程，促进WHOI的美国团队与IFM-GEOMAR的德国团队之间的思想和实用信息交流，以及加强CoPI的早期工作。获得的数据也将与过去研究过赤道深部变率的其他研究人员共享；这些科学家将被邀请参与分析工作。

More than 30 years have passed since equatorial deep jets were first observed in the Indian Ocean. In the intervening decades, seeming long-lived zonal deep jets have also been observed/inferred in the Pacific and Atlantic Oceans, along with variability at shorter period (most notably, meridional motions on the equator at roughly monthly timescales). Both analytical and numerical modeling have been applied to investigate the dynamics of deep equatorial motions and several theories for have been forwarded, however none have proven completely satisfactory. Basic characterization of the deep variability in the Atlantic is hampered by limited observations. High vertical resolution ship observations are available at intervals of 6 months or longer; temporally-continuous moored time series from discrete sensors fail to resolve the high wavenumber character of the near-equatorial motions. This project will collect the most extensive measurements of deep equatorial Atlantic variability thus far. It is a joint U.S.- German study of deep ocean variability in the equatorial Atlantic in conjunction with an existing upper ocean moored measurement effort funded by the German Federal Ministry of Education and Research. The new data will be key to evaluating existing theories of deep equatorial motions (perhaps motivating new ideas) and validating numerical models. Beyond scientific interaction, this project will also facilitate the sharing of technical mooring procedures between WHOI and IFM-GEOMAR personnel.Moored Profiler instruments will be prepared by both Woods Hole Oceanographic Institution and The Leibniz Institute of Marine Sciences at the University of Kiel (IFM-GEOMAR) technicians and mounted on 5 separately-funded moorings along 23W between Lats. 2N and 2S and programmed to repeatedly sample between approximately 1000 and 3500 m depth for a 1.5 year period (November 2009?spring 2011). The combined observing system (existing upper ocean moored ADCP and discrete T/S sensors with added deep Moored Profilers) will return at lowest-common-denominator: 16-m vertical resolution velocity profiles at 4-d interval from the surface to 3500 m depth and T/S information at ~10 levels through the upper ocean increasing to ~1 m vertical resolution at depth. The acquired data will be jointly processed and analyzed by investigators from WHOI and IFM-GEOMAR in conjunction with available remote sensing data and numerical model output. The data will also be shared with fellow North American investigators who have studied deep equatorial variability in the past; these scientists will be invited to contribute to the analysis effortThe main research goal is to develop a better understanding of the dynamics of the deep equatorial Atlantic variability and the effects of these motions on the ocean general circulation. One particular focus of the analysis will be the relationships between the Atlantic Deep Western Boundary Current and the equatorial deep jets, in particular, communication of Atlantic Meridional Overturning Circulation variability between hemispheres.The broader impacts of the study will be better understanding of processes important for climate dynamics, exchange of ideas and practical information between the US team from WHOI and German team from IFM-GEOMAR, and enhancing the early career of the CoPI. The acquired data will also be shared with other investigators who have studied deep equatorial variability in the past; these scientists will be invited to contribute to the analysis effort.