Variations in the Intensity of Small-Scale Mixing in the Main Thermocline
Variations in the Intensity of Small-Scale Mixing in the Main Thermocline
复制标题
主温跃层小规模混合强度的变化
DOI：
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发表时间：
1977
期刊：
影响因子：
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通讯作者：
M. Gregg
中科院分区：
文献类型：
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作者：
M. Gregg
在北太平洋中部（28°N, 155°W）的同一地点进行的三次巡航发现，温度谱显示的小尺度湍流活动水平存在明显差异。各深度的温度梯度归一化方差均值（Cox数）分别为2（1971年9月）、10（1973年6月）和59（1974年2月）。冬季在南太平洋相应地点（28°S, 155°W）采集的数据与后者的值相似。最活跃的记录出现在主温跃层以下或季节性温跃层中，在2 ~ 90 cpm范围内呈现出坡度在+1 ~ +1之间的梯度光谱。较不活跃的记录在10 ~ 10 cpm范围内被扩散切断。在低波数处，微观结构活性水平与光谱水平无关。较活跃记录的差异是由几个几米厚的强烈斑块造成的，这些斑块在梯度上的变化范围大于十年。
Abstract Three cruises to the same site in the central North Pacific (28°N, 155°W) found naked differences in the levels of small-scale turbulent activity as indicated by spectra of temperature profiles. Considering the data from all depths the mean values of the normalized variance of the temperature gradients, or Cox number, were 2 (September 1971), 10 (June 1973) and 59 (February 1974). Data taken during winter at a corresponding site in the South Pacific (28°S, 155°W) were similar to the latter values. The most active records were found below the main thermocline or in the seasonal thermocline and exhibited gradient spectra with slopes between +½ and +1 from 2 cpm to greater than 90 cpm. The less active records were diffusively cut off for k>10 cpm. The level of microstructure activity was not related to the spectral levels at lower wavenumber. The variance of the more active records was contributed by several intense patches a few meters thick, which had ranges of greater than a decade in the gradien...