The Northwestern North Atlantic: Continuing a Retrospective Analysis of Observations from the CMV Oleander on the Shelf and Slope

美国东北部的大陆架一直被强调为海平面上升和海洋变暖的热点，在平均趋势上叠加了强烈的年际到年代际变化。这些变化对气候和商业渔业都有重要影响。这项研究将考察北大西洋西北部大陆架和上坡的这种变异性。它将使用商业志愿者观测船CMV Oleander收集的长期观测数据，该船的航线定期穿越北大西洋的四个重要区域-中大西洋海湾(MAB)大陆架、坡海、墨西哥湾流和马尾藻海。在新泽西州和百慕大之间的预定往返航程中，这些穿越每周进行一次。这项工作将利用涵盖1992-2018年期间的现有完整夹竹桃数据集，分析将侧重于人与生物圈大陆架和上坡的年际变化。这是一个早期项目的延续，它将支持一名研究生完成博士研究。来自Oleander观测的数据产品将通过现有的Oleander计划网站提供给科学界。CMV Oleander收集了大陆架和上坡的温度横截面(跨度42年)、表面温度和盐度测量(跨度42年)和速度截面(跨度28年)，使用一次性水温仪(XBTS)、水桶测量和温度盐度仪(TSG)以及船上声学海流多普勒剖面仪(ADCP)。这个数据集的独特之处在于它的高分辨率，持续时间长达数十年，以及共同定位的温度和速度观测。通过将这些数据与辅助的现场和遥感数据集相结合，该项目将调查驱动陆架温度、陆架破裂喷流和斜坡喷流速度结构和传输的低频变化的过程，重点是过去28年变化的物理机制。这项研究还将调查在之前的一些研究中注意到但尚未被充分探索的坡度喷流，在夹竹桃数据集中是常规特征还是短暂特征。此外，一套新的科学仪器(包括盐度剖面)目前正装备在新船上，以取代旧船。作为这项研究的一部分，调查人员将监督仪表组的过渡，以确保数据收集质量的连续性，并将已经收集的时间序列无缝地延伸到未来，适合于捕捉大陆架和斜坡上的年际和年代际海洋变化。重点将是将旧平台的结果与该区域盐度和速度剖面的新测量结果进行比较。要研究的变异性将开阔海洋(墨西哥湾流、西部深部边界流和大西洋子午线翻转环流)与大陆架现象(中大西洋海湾大陆架环流、大陆架破裂喷流动力学和生态系统动力学)联系起来。先前项目的结果已经在气候(AMOC)和大陆架(中大西洋海湾物理海洋学和气象学，MABPOM)工作室中展示了(新的结果将被公布)。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The shelves along the northeastern U.S. have been highlighted as a hotspot of sea level rise and ocean warming with strong interannual to decadal variability superimposed on a mean trend. These changes have important implications for both climate and commercial fisheries. The study will examine this variability in the northwestern North Atlantic over the continental shelf and upper slope. It will use long-duration observations collected by the CMV Oleander, a commercial volunteer observing ship, whose route regularly crosses four important regions of the North Atlantic Ocean - the Middle Atlantic Bight (MAB) shelf, the Slope Sea, the Gulf Stream, and the Sargasso Sea. The crossings occur once a week during the vessel's scheduled roundtrip transits between New Jersey and Bermuda. This work will utilize the existing, complete Oleander datasets covering the period 1992 - 2018 and the analysis will focus on the interannual variability on the MAB shelf and over the upper slope. This is the continuation of an earlier project and it will support the completion of a graduate student's Ph.D. research. The data products derived from the Oleander observations will be made available to the science community via existing Oleander Program websites.The CMV Oleander has collected temperature cross-sections of the shelf and upper slope (spanning 42 years), surface temperature and salinity measurements (spanning 42 years), and velocity sections (spanning 28 years) with expendable bathythermographs (XBTs), bucket measurements and a thermosalinograph (TSG), and shipboard acoustic current Doppler profilers (ADCPs). This data set is unique in terms of its high resolution, extended duration over multiple decades, and co-located temperature and velocity observations. By combining these data with auxiliary in situ and remote-sensing datasets, the project will investigate the processes that drive the low-frequency variability in shelf temperature, shelf break jet and slope jet velocity structure and transport, with a focus on the physical mechanisms underlying the variability of the last 28 years. This study also will investigate whether the slope jet, noted in some previous research but not yet well-explored, is a regular or an ephemeral feature in the Oleander data set. In addition, a new suite of scientific instrumentation (including salinity profiles) is currently outfitted on the new ship commissioned to replace the old one. As part of this study, the investigators will oversee the transition of instrumentation packages as to ensure continuity in data collection quality and seamless extension of the already collected time-series into the future, suitable for capturing interannual and decadal ocean changes on the shelf and slope. Emphasis will be placed on comparing the results from the old platform with the new measurements of salinity and velocity profiles over the region. The variability to be studied links open-ocean (Gulf Stream, Deep Western Boundary Current, and Atlantic Meridional Overturning Circulation, AMOC) to shelf phenomena (Middle Atlantic Bight shelf circulation, shelf break jet dynamics, and ecosystem dynamics). Results from the prior project have been (and new results will be) presented in both climate (AMOC) and continental shelf (Middle Atlantic Bight Physical Oceanography and Meteorology, MABPOM) workshops.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.