A TRANSPACIFIC HYDROGRAPHIC SECTION ALONG LATITUDE 24-DEGREES-N - THE DISTRIBUTION OF PROPERTIES IN THE SUBTROPICAL GYRE
A TRANSPACIFIC HYDROGRAPHIC SECTION ALONG LATITUDE 24-DEGREES-N - THE DISTRIBUTION OF PROPERTIES IN THE SUBTROPICAL GYRE
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DOI：
10.1016/s0198-0149(12)80002-1
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发表时间：
1991-01-01
期刊：
影响因子：
--
通讯作者：
SWIFT, J
中科院分区：
文献类型：
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作者：
ROEMMICH, D;MCCALLISTER, T;SWIFT, J
1985年春季完成了沿沿着24度的跨太平洋水文剖面的密集采样。 这里描述的数据的属性的空间分布，分布沿着等密面，并在可能的情况下，这些分布的关系，大规模的太平洋环流。 源自亚热带的近地表沃茨在大洋中部显示出最大盐度，西部的盐度较低，原因是降雨量较大，东部的盐度较低，原因是来自北部的水的平流。 在下一层，含有来自次极地的沃茨，这些沃茨的低盐度和高溶解氧浓度在东部海洋最为明显，在那里，次极地海水顺时针进入亚热带环流。 溶解氧浓度和盐度的模式之间的差异表明，水平平流和上升流有助于观察到的东部边界附近的分布，这两个示踪剂包含独立的信息。 在上千米，东太平洋比西太平洋具有更高的示踪剂信号和更陡的性质梯度，深太平洋一直被认为是最均匀的海洋。 虽然属性梯度很小，他们是显着的，它被发现，在所有的等密度面以下的上千米盐度增加，溶解氧浓度减少向东的全流域尺度。 这些纬向梯度在深渊中最弱，那里有大量的南部水的净输入，在中层最强。 垂直扩散是可能的原因，在这种模式的均匀性在这么多的深北太平洋，与耗氧量在沃茨的年龄较大的东部也是一个合理的contributor.With高度采样的数据集，如24度N的跨太平洋部分，它是适当的问需要多少站来定义属性分布和估计大规模的环流和运输。 估计地转输送需要高的空间分辨率，以检测在所有深度的倾斜地形附近的流量。 一个50%的抽取的24度N站模式产生严重退化的估计运输。
An intensively sampled transpacific hydrographic section along 24-degrees-N was completed in the spring of 1985. The data are described here in terms of the spatial distribution of properties, the distribution along isopycnal surfaces, and, where possible, the relationship of these distributions to the large-scale circulation of the Pacific Ocean. Near-surface waters of subtropical origin display a salinity maximum in mid-ocean, with lower salinity to the west due to greater rainfall and lower salinity in the east due to advection of water from the north. In the next layers down, containing waters of subpolar origin, the low salinity and high dissolved oxygen concentrations of those waters are most pronounced in the eastern ocean where the subpolar water is swept clockwise into the subtropical gyre. Differences between patterns of dissolved oxygen concentration and salinity indicate that both horizontal advection and upwelling contribute to observed distributions near the eastern boundary and that the two tracers contain independent information. In the upper kilometer, the eastern Pacific is richer in tracer signals and has steeper property gradients than the west.The deep Pacific has long been recognized to be the most uniform of the oceans. Although property gradients are small, they are significant, and it is found that on all isopycnal surfaces below the upper kilometer salinity increases and dissolved oxygen concentration decreases towards the east on basin-wide scales. These zonal gradients are weakest in the abyss, where there is a substantial net input of southern water, and strongest at mid-depth. Vertical diffusion is the likely cause of the uniformity in this pattern over so much of the deep North Pacific, with oxygen consumption in waters of greater age in the east also being a plausible contributor.With a highly sampled data set such as the 24-degrees-N transpacific section it is appropriate to ask how many stations are required to define property distributions and to estimate large-scale circulation and transport. Estimation of geostrophic transport requires high spatial resolution to detect flow near sloping topography at all depths. A 50% decimation of the 24-degrees-N station pattern yields a severe degradation in the estimation of transport.