Analysis of the Guiana Abyssal Gyre Experiment [GAGE] Dataset

圭亚那深海环流实验 [GAGE] 数据集分析

• 批准号: 0241505
• 负责人: Michael McCartney
• 金额: $ 41.9万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-03-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0241505&HistoricalAwards=false
• 关键词: Analysis; Guiana; Abyssal; Gyre; Experiment

0241505 McCartneyThe Guiana Abyssal Gyre Experiment (GAGE) placed a moored array of current meters across the Guiana Basin, to measure the deep boundary current and to attempt to detect and quantify the hypothesized northward flow to its east. As implemented the array was placed at 16 N for 27 months, and GAGE was enhanced through collaboration with a German .Meridional Overturning Variability Experiment. (MOVE, based at U. Kiel). Together the GAGE/MOVE program fielded 10 moorings with 72 current meters (measuring temperatures and currents) and 48 moored temperature/salinity instruments (CTDs). Considerable shipboard CTD measurements were made in the Guiana Basin in concert with mooring deployments and recoveries. GAGE completed its fieldwork in May 2002, with the exception of one GAGE mooring that failed to release and will be recovered in March of 2003. A first look at the results from the moored instruments, confirms the Gambia Abyssal Gyre hypothesis. The deep western boundary current at 16 N is strong, estimated as 38 Sverdrups. It has an unexpected two-regime structure in hydrography and in measured currents: an onshore regime with strong southward flow near 1600 m, declining with depth to weak flow near 4000 m, and an offshore regime with strong flow near 3600-4600 m, declining in strength upwards and reversing to northward flow at 1600 m. The hypothesized northward recirculation is found in three regimes. Immediately offshore and adjacent to the deep western boundary current the entire water column between 1600 m and 5400 m flows northward. On the opposite side of the Guiana Basin adjacent to the Mid-Atlantic Ridge northward flow extends from the seafloor at 5400 m to 3600 m. All array instruments across the Basin at or below 3600 m, except one in the deep boundary current, exhibit northward flow. This yields a surprisingly strong flow of what is called Antarctic Bottom Water, the coldest abyssal water. Together these northward flow elements are preliminarily estimated as 19-23 Sverdrups, yielding a net transport of 15-19 Sverdrups, the expected amplitude for the cold limb of the overturning circulation. The large GAGE/MOVE datasets will be worked up in collaboration with the MOVE scientists. The measured currents and the measured hydrography will be combined to produce a complete quantitative characterization of deep flow at 16 N, including its variabilities in amplitude and structure. With that as a powerful constraint, the full hydrographic dataset within the Guiana Basin will be reexamined to fully characterize the Guiana Abyssal Gyre and establish its role in the cold limb of the meridional overturning circulation.

0241505 McCartney The Guiana Abyssal Gyre实验（GAGE）在圭亚那盆地上放置了一个停泊的电流仪表，以测量深边界电流，并试图检测和量化向北的北部。 实施后，将阵列放置在16 N，持续27个月，并通过与德国人的倾覆可变性实验协作增强了GAGE。 （移动，位于U. Kiel）。 量规/移动程序一起将10个系泊设备带有72个电流仪（测量温度和电流）和48个系泊温度/盐度仪器（CTD）。 在圭亚那盆地进行了相当大的船舶CTD测量，并与系泊部署和恢复共同进行。 Gage于2002年5月完成了现场工作，除了一台无法释放的量规系泊，将于2003年3月回收。首次查看了系泊仪器的结果，证实了冈比亚的深渊Gyre假设。 16 N处的深西边界电流很强，估计为38 sverdrups。 它在水文学和测得的电流中具有意外的两极结构：在1600 m接近的陆上状态下，陆上有强大的向南流动，深度为4000 m接近4000 m的弱流量，并且在3600-4600 m接近3600-4600 m的近海状态下，强度向上下降，向北下降至1600 m。 假设的北向再循环是在三个政权中发现的。 立即在近海和深处的西部边界附近，整个水柱在1600 m至5400 m之间，向北流动。 在圭亚那盆地的另一侧，与中大西洋山脊向北流相邻，从海底延伸到5400 m，延伸到3600 m。 除了深边界电流中的一个或低于3600 m以下的盆地上的所有阵列仪器均显示向北流动。 这产生了令人惊讶的强烈流动，即所谓的南极底水，最冷的深渊水。 这些北向元素共同估计为19-23 sverdrups，净运输净为15-19 sverdrups，这是倾覆循环的冷肢的预期幅度。 大型量规/移动数据集将与移动科学家合作制定。 测得的电流和测得的水文将合并，以产生16 N处的深流量的完整定量表征，包括其在振幅和结构中的变化。 由于这是一个强大的约束，将重新审查圭亚那盆地内的完整水文数据集，以充分表征圭亚那的深渊Gyre并确立其在子午倾覆循环的冷肢中的作用。