Rates and mechanisms of turbulent dissipation and mixing in the Southern Ocean: Results from the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES)
Rates and mechanisms of turbulent dissipation and mixing in the Southern Ocean: Results from the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES)
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DOI：
10.1002/jgrc.20217
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发表时间：
2013-06
影响因子：
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通讯作者：
K. Sheen;J. Brearley;A. N. Garabato;D. Smeed;S. Waterman;J. Ledwell;M. Meredith;L. S. Laurent
中科院分区：
文献类型：
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作者：
K. Sheen;J. Brearley;A. N. Garabato;D. Smeed;S. Waterman;J. Ledwell;M. Meredith;L. S. Laurent
研究发现，湍流耗散率从东南太平洋的O 1 - 10 - 10 Wk g-1增加到斯科舍海的O 1 - 10 - 9 Wk g-1，通常在海底一公里内达到3 - 10 - 9 Wk g-1。湍流混合的增强水平与强近底流、粗糙地形和内部波场被发现具有增强的能量、较低的惯性频率内容和向上传播能量的主导地位的区域相关。这些结果强烈表明，底生内波起着决定在ACC湍流耗散的空间分布的主要作用。与底生内波生成过程中使用波辐射理论计算的能量通量，并发现在东南太平洋和斯科舍海的14 mW m2之间变化。通常情况下，10%-30%的这种能量被发现在海床1公里内消散。从精细结构参数化和microstructurederived估计推断的湍流耗散率之间的比较表明，在近场的波生成站点的波-波相互作用物理的显着偏离。
turbulent dissipation rates are found to increase from O 1 � 10 � 10 Wk g � 1 �� in the Southeast Pacific to O 1 � 10 � 9 Wk g � 1 �� in the Scotia Sea, typically reaching 3 � 10 � 9 Wk g � 1 within a kilometer of the seabed. Enhanced levels of turbulent mixing are associated with strong near-bottom flows, rough topography, and regions where the internal wavefield is found to have enhanced energy, a less-inertial frequency content and a dominance of upward propagating energy. These results strongly suggest that bottomgenerated internal waves play a major role in determining the spatial distribution of turbulent dissipation in the ACC. The energy flux associated with the bottom internal wave generation process is calculated using wave radiation theory, and found to vary between 0.8 mW m � 2 in the Southeast Pacific and 14 mW m � 2 in the Scotia Sea. Typically, 10%–30% of this energy is found to dissipate within 1 km of the seabed. Comparison between turbulent dissipation rates inferred from finestructure parameterizations and microstructurederived estimates suggests a significant departure from wave-wave interaction physics in the near-field of wave generation sites.