Spatial scales of temperature and flow in Drake passage
Spatial scales of temperature and flow in Drake passage
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德雷克海峡温度和流量的空间尺度
DOI：
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发表时间：
1980
期刊：
影响因子：
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通讯作者：
T. Whitworth
中科院分区：
文献类型：
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作者：
F. Sciremammano;R. Pillsbury;W. Nowlin;T. Whitworth
德雷克海峡3年（1975年，1976年和1977年）的流速计数据的分析是用来评估的温度和流量的垂直和水平尺度。结果发现，温度和电流的波动高度相关的垂直中深度范围内。唯一的例外是上层（300-500米）的温度结构，它很复杂，与较深层的温度结构没有很好的相关性，在3000米及以下的深度，电流变化相对增加。大多数的测量都是在极地锋区的南部边缘附近，在那里发现，温度波动的水平尺度在100-110公里处的通过和横向上大致相等。如果使用整个通道的数据，则该比例尺减小到约80 km。在通过和横向通道方向的速度波动被发现是狭窄的（30-40公里的顺序）正常的流动方向和拉长（55-80公里）平行于it. These测量的空间尺度被证明是一致的观测报告的个别中尺度扰动从这个地区的南极绕极流。所观察到的扰动通常是与极锋相关的窄电流核心的曲折或横向偏移的形式，或者是由该电流的环路分离形成的环。极锋，以及相关的电流核心，被发现迁移北部和南部的时间尺度上的几个月。所有3年的记录都表明，在南半球冬季，锋面向北移动。虽然在大间隔（>100 km）的相关性一般很小，但对它们的符号结构的分析表明，在通道宽度的一半量级的尺度上存在一个小的响应。这种响应符合从消耗性深温仪痕迹（XBT）和水文调查中发现的一般分带模式。
An analysis of 3 years of current meter data (1975, 1976, and 1977) from Drake Passage is used to assess the vertical and the horizontal scales of temperature and flow. It is found that temperature and current fluctuations are highly correlated vertically in the mid-depth range. The only exceptions are in the temperature structure in the upper layers (300–500 m) which is complex and not well correlated with that in the deeper layers and a relative increase in current variability at depths near 3000 m, and below. Most of the measurements were near the southern edge of the Polar Frontal Zone where it is found that the horizontal scales for temperature fluctuations are approximately equal in the through- and the across-passage directions at 100–110 km. If the data from the entire passage is used, this scale is reduced to approximately 80 km. The velocity fluctuations in the through- and the across-passage directions are found to be narrow (of the order of 30–40 km) normal to their flow direction and elongated (55–80 km) parallel to it. These measured spatial scales are shown to be consistent with observations of individual mesoscale disturbances reported from this region of the Antarctic Circumpolar Current. The observed disturbances are generally in the form of meanders or lateral excursions of the narrow current core associated with the polar front or of rings formed from separations of loops of this current. The polar front, and the associated current core, are found to migrate north and south on a time scale of months. A northward shift of the front during the austral winter is indicated in the records from all 3 years. Although the correlations at large separations (>100 km) were generally small, an analysis of their sign structure indicates a small response is present at scales on the order of half the passage width. This response fits into the general zonation pattern found from expendable bathythermograph traces (XBT) and hydrographic surveys.