Shear at the Base of the Oceanic Mixed Layer Generated by Wind Shear Alignment
Shear at the Base of the Oceanic Mixed Layer Generated by Wind Shear Alignment
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DOI：
10.1175/jpo-d-12-0104.1
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发表时间：
2013-08
影响因子：
3.5
通讯作者：
L. Brannigan;Y. Lenn;T. Rippeth;E. McDonagh;T. Chereskin;J. Sprintall
中科院分区：
文献类型：
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作者：
L. Brannigan;Y. Lenn;T. Rippeth;E. McDonagh;T. Chereskin;J. Sprintall
观测被用来评估一个简单的理论模型的生成近惯性剪切尖峰的基础上的开放的海洋混合层时，上层海洋显示一个两层结构。该模型预测，风矢量和切变矢量的对齐可以产生切变平方的大变化。德雷克海峡的层结和切变方差的气候学，这表明这些假设是最适用于夏季，秋季和春季，但不是很适用于冬季。温度，盐度，和速度数据从高空间分辨率巡航在德雷克海峡表明，该模型不能预测所有的剪切方差的大的变化，该模型是最有效的预测剪切平方的变化时，它出现由于近惯性风驱动的电流，而不需要旋转共振风应力。在强分层过渡层上方有均匀混合层的情况下，该模式也更有效。1999年至2011年，对另外242个德雷克通道样带的旋转光谱和统计分析证实了这种剪切尖峰机制的存在，特别是在夏季、春季和秋季分层较强时。
Observations are used to evaluate a simple theoretical model for the generation of near-inertial shear spikes at the base of the open ocean mixed layer when the upper ocean displays a two-layer structure. The model predicts that large changes in shear squared can be produced by the alignment of the wind and shear vectors. A climatology of stratification and shear variance in Drake Passage is presented, which shows that these assumptions are most applicable to summer, fall, and spring but are not highly applicable to winter. Temperature, salinity, and velocity data from a high spatial resolution cruise in Drake Passage show that the model does not predict all large changes in shear variance; the model is most effective at predicting changes in shear squared when it arises owing to near-inertial wind-driven currents without requiring a rotating resonant wind stress. The model is also more effective where there is a uniform mixed layer above a strongly stratified transition layer. Rotary spectral and statistical analysis of an additional 242 Drake Passage transects from 1999 to 2011 confirmed the presence of this shear-spiking mechanism, particularly in summer, spring, and fall when stratification is stronger.