Observations and Analysis of Deep Equatorial Variability in the Atlantic

自从在印度洋首次观测到赤道深喷流以来，已经过去了30多年。在其间的几十年中，在太平洋和大西洋也观察到/推断出似乎寿命较长的纬向深急流，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在每月的时间尺度上)。分析和数值模拟都被用来研究赤道深部运动的动力学，提出了几种理论，但没有一种是完全令人满意的。由于观测有限，大西洋深层变化的基本特征受到阻碍。高垂直分辨率的船舶观测间隔6个月或更长时间可用；离散传感器的时间连续系泊时间序列无法分辨近赤道运动的高波数特征。该项目将收集迄今为止对赤道大西洋深层变化最广泛的测量结果。这是美国和德国对赤道大西洋深海变异性的联合研究，以及由德国联邦教育和研究部资助的现有上层海洋系泊测量工作。新的数据将是评估现有的赤道深层运动理论(也许会激发新的想法)和验证数值模型的关键。除了科学上的互动，该项目还将促进世界卫生组织和IFM-GEOMAR人员分享技术系泊程序。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)的技术人员将共同制作系泊剖面仪，并安装在LATS之间23W方向的5个单独出资的系泊设备上。2N和2S，编程为在大约1000米和3500米深度之间重复采样，为期一年半(2009年11月？2011年春季)。组合观测系统(现有的上层系泊ADCP和离散的T/S传感器并增加了深部系泊剖面仪)将以最小的公约数返回：从表层到3500米深度的4维间隔的16米垂直分辨率速度剖面，以及通过上层海洋的~10层的T/S信息，在深度增加到~1米的垂直分辨率。所获得的数据将由世界卫生组织和IFM-GEOMAR的调查人员结合现有的遥感数据和数值模式输出进行联合处理和分析。这些数据还将与过去研究过赤道深层变率的北美其他研究人员分享；这些科学家将应邀为分析工作作出贡献。主要研究目标是更好地了解赤道深层大西洋变率的动态以及这些运动对海洋一般环流的影响。分析的一个特别重点将是大西洋深西部边界流与赤道深急流之间的关系，特别是大西洋经向翻转环流在半球之间的联系。这项研究的更广泛影响将是更好地了解对气候动力学重要的过程，世界卫生组织美国小组和IFM-GEOMAR德国小组之间的思想交流和实用信息，并促进COPI的早期工作。所获得的数据还将与过去研究过赤道深层变异性的其他研究人员分享；这些科学家将受邀为分析工作作出贡献。

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.