Microstructure Estimates of Turbulent Salinity Flux and the Dissipation Spectrum of Salinity
Microstructure Estimates of Turbulent Salinity Flux and the Dissipation Spectrum of Salinity
复制标题
湍流盐度通量的微观结构估计和盐度耗散谱
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
J. Moum
中科院分区：
文献类型：
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作者：
J. Nash;J. Moum
由于在混合的最小尺度上测量盐度的复杂性，直接测定海洋中盐度的不可逆湍流通量一直是不可能的。提出了在缓慢下降的垂直微结构剖面仪上使用组合的快速电导率/温度探头进行测量的湍流盐度微结构的分析。选择了四百个海洋湍流斑块进行分析。盐度梯度 C 的高分辨率光谱在粘性 Sz 对流子范围中表现出近似 k11 依赖性，然后在粘性扩散子范围中出现滚降，如 Batchelor 所建议的，并且允许确定盐度方差 xS 的耗散率。将来自耗散尺度测量的不可逆盐度通量估计值（来自 xS，遵循 Osborn 和 Cox）与来自相关方法 (^w9S9&)、来自 TKE 耗散测量（遵循 Osborn）以及湍流热通量的估计值进行比较。发现盐与热湍流扩散率之比dx 5 KS/KT 5 xS/xT(dT/dS) 2 为0.6、dx、1.1。
Direct determination of the irreversible turbulent flux of salinity in the ocean has not been possible because of the complexity of measuring salinity on the smallest scales over which it mixes. Presented is an analysis of turbulent salinity microstructure from measurements using a combined fast-conductivity/temperature probe on a slowly falling vertical microstructure profiler. Four hundred patches of ocean turbulence were selected for the analysis. Highly resolved spectra of salinity gradient C exhibit an approximate k11 dependence in the viscous‐ Sz convective subrange, followed by a roll-off in the viscous‐diffusive subrange, as suggested by Batchelor, and permit the dissipation rate of salinity variance xS to be determined. Estimates of irreversible salinity flux from measurements of the dissipation scales (from xS, following Osborn and Cox) are compared to those from the correlation method (^w9S9&), from TKE dissipation measurements (following Osborn), and to the turbulent heat flux. It is found that the ratio of haline to thermal turbulent diffusivities, dx 5 KS/KT 5 xS/xT(dT/dS) 2 is 0.6 , dx , 1.1.