Analysis of the Guiana Abyssal Gyre Experiment [GAGE] Dataset

0241505 McCartney圭亚那深海环流实验（GAGE）在圭亚那盆地上放置了一个系泊的海流计阵列，以测量深层边界流，并试图检测和量化其东部的假设北向流。 在实施时，该阵列在16 N下放置了27个月，并且通过与德国子午线翻转可变性实验的合作增强了GAGE。 (MOVE，总部设在美国。 基尔）。 GAGE/MOVE计划共部署了10个系泊设备，72个海流计（测量温度和海流）和48个系泊温度/盐度仪器（CTD）。 在圭亚那盆地进行了相当多的船上CTD测量，与系泊部署和回收一致。 GAGE于2002年5月完成了其现场工作，但有一个GAGE系泊设备未能释放，将于2003年3月收回。 首先看一下系泊仪器的结果，证实了冈比亚深海环流假说。 16 N处的深部西边界流很强，估计为38 Sverdrups。 在水文学和测量的海流中，它有一个意想不到的两种状态结构： 在1600 m附近有一个向南流动的陆上流态，随着深度的增加，在4000 m附近逐渐减弱为弱流;在3600-4600 m附近有一个向南流动的离岸流态，在1600 m附近强度逐渐减弱，并在1600 m处逆转为向北流动。 假设的北向回流被发现在三个制度。 紧靠近海和邻近西部深层边界流，1600米至5400米之间的整个水柱向北流动。 在圭亚那海盆的另一侧，邻近大西洋中脊，向北的水流从海底延伸到5400米至3600米。 所有的阵列仪器在盆地或低于3600米，除了一个在深边界流，表现出向北流动。 这就产生了一种惊人的强大的流动，称为南极底层水，最冷的深海水。 这些向北的气流要素加在一起，初步估计为19-23斯维德鲁普，产生15-19斯维德鲁普的净输送，这是翻转环流冷翼的预期幅度。 大型GAGE/MOVE数据集将与MOVE科学家合作完成。 将测得的电流和测得的水文相结合，以产生一个完整的定量表征深流在16 N，包括其在振幅和结构的变化。 有了这一强大的约束，圭亚那盆地内的完整水文数据集将被重新审查，以充分描述圭亚那深海环流的特征，并确定其在赤道翻转环流冷翼中的作用。

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.