The Oleander Project: Sustained Observation of Ocean Currents and Transports in the Gulf Stream and Adjacent Waters from New York to Bermuda

0241654罗斯比十年前启动了一项计划，通过CMV Oleander集装箱船直接测量从美国大陆架到百慕大的上层洋流，特别关注墨西哥湾流强度的长期变化。由于每周向百慕大运送货物，可以对墨西哥湾流和邻近的环流进行高水平分辨率的重复采样，从而能够以以前无法达到的绝对精度估计上层海洋的输送及其变化性。尽管对上层海洋运输量的任何单一估计都会在15%-20%的范围内存在固有的不确定性，但重复抽样最多只能将其减少到几个百分点。在1993-2001年Oleander观测期间，观测到的墨西哥湾流输送的最大年际变化在每年估计时为峰顶之间的+/-8%。由于这些变化似乎发生在北大西洋涛动特有的时间尺度上，目前还不清楚这些是典型的、小的还是大的数字。目前，人们也无法区分关于强迫机制的不同假设。该项目将把夹竹桃抽样计划再持续五年。拟议的改进措施包括安装新的最先进的声学多普勒海流剖面仪和光学罗盘。这将改善速度场的一致采样，使其达到显著更深的深度。国家海洋渔业局将继续每月对夹竹桃赛道上的消耗性浴温记录仪(XBT)进行投射。科学目标包括调查四个海洋学体制(外大陆架、斜坡海、墨西哥湾流和马尾藻海)之间的联系及其与大尺度强迫场的联系。特别是，到目前为止获得的观测结果表明，温盐对西北大西洋的可变性的作用可能比之前认识到的更强。这些都是复杂的问题，当Oleander数据集与其他研究和建模工作结合使用时，将会更加有效。为了促进这种协同效应，夹竹桃每次进入港口时都将获得数据，并将处理后的数据近乎实时地发布在基于网络的服务器上。随着对实时海洋预报的日益重视，这些观测和相关产品可以在预报验证和模式改进方面发挥越来越有用的作用。其他研究活动可以利用这些数据，并可能发现围绕这些数据可用性设计现场计划是有利的。还建议编写观察报告，以供更广泛的公众，特别是航海界使用。罗德岛大学海洋学研究生院有一个针对K-12社区的活跃的基于网络的方案，将探索这一领域的合作。

0241654 RossbyTen years ago a program was initiated to directly measure upper-ocean currents from the U.S. continental shelf to Bermuda from a container vessel, the CMV Oleander, with special focus on long-term variations in the strength of the Gulf Stream. The high horizontal resolution repeat sampling of the Gulf Stream and adjacent gyres, made possible by the weekly shipping to Bermuda, has led to estimates of upper-ocean transports and their variability with an absolute accuracy previously unachievable. While any single estimate of upper-ocean transport will have an inherent uncertainty in the 15-20% range, repeat sampling can reduce this to just a few percent at most. For the 1993-2001 Oleander observing period, the largest observed inter-annual variations in Gulf Stream transport had a magnitude of +/-8%, peak-to-peak, when estimated annually. Since these variations appear to occur on time scales characteristic of the North Atlantic Oscillation, it is not yet clear whether these are typical, small, or large numbers. Nor can one at present distinguish between different hypotheses regarding forcing mechanisms. This project will continue the Oleander sampling program for another five years. Proposed enhancements include the installation of a new state-of-the art acoustic Doppler current profiler and optical compass. These will improve consistent sampling of the velocity field to significantly greater depths. EXpendable BathyThermograph (XBT) casts along the Oleander track will continue to be taken monthly by the National Marine Fisheries Service. Scientific objectives include the investigation of linkages between four oceanographic regimes (outer continental shelf, Slope Sea, Gulf Stream, and Sargasso Sea) and their connections to large-scale forcing fields. In particular, observations obtained to date suggest a stronger thermohaline role to the variability of the Northwest Atlantic than perhaps previously recognized. These are complex issues and the Oleander data set will be far more effective when used in conjunction with other studies and modeling efforts. To facilitate such synergies, the Oleander's data will be acquired each time she enters port, and the processed data posted in near real-time on a web-based server. With a growing focus on real-time ocean forecasting, these observations and related products can play an increasingly useful role in forecast validation and model improvements. Other research activities can avail themselves of these data, and may find it advantageous to design field programs around this data availability. It is also proposed to prepare observations for use by a wider public, particularly the sailing community. The Graduate School of Oceanography at the University of Rhode Island has an active web-based program for the K-12 community and collaborations in this area will be explored.