Evolution of Oceanic Near-Surface Stratification in Response to an Autumn Storm
Evolution of Oceanic Near-Surface Stratification in Response to an Autumn Storm
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DOI：
10.1175/jpo-d-19-0007.1
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发表时间：
2019-11
影响因子：
3.5
通讯作者：
N. Lucas;A. Grant;T. Rippeth;J. Polton;M. Palmer;L. Brannigan;S. Belcher
中科院分区：
文献类型：
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作者：
N. Lucas;A. Grant;T. Rippeth;J. Polton;M. Palmer;L. Brannigan;S. Belcher
了解控制海洋表面边界层（OSBL）演变的过程是获得精确模拟海气热通量和微量气体通量的先决条件。本文介绍了在海洋表面混合、海洋次中尺度相互作用研究（OSMOSIS）期间对东北大西洋湍流动能耗散率（ε）、温度、盐度、流结构和波场进行的9.5天的观测结果。本研究的重点是在此期间经过观测区的风暴。OSBL中的ε分布与Langmuir湍流的大涡模拟（LES）的分布一致。在OSBL底部的过渡层（TL）中，ε以局部惯性频率周期性变化。发展了一个简单的OSBL体模型和TL中剪切驱动湍流的参数化。ε的参数化是基于OSBL的动量平衡和TL上的切变的假设。预测的加深速率、热收支和OSBL中的惯性流与观测结果吻合良好，ε的观测值与使用参数化预测的值之间的一致性也是如此。之前的一项研究报告称，这场风暴过后，OSBL底部的风切变排列增强，导致消散峰值升高。新的参数化方法没有预测到耗散的峰值，这意味着它们不是风暴期间耗散的重要来源。
Understanding the processes that control the evolution of the ocean surface boundary layer (OSBL) is a prerequisite for obtaining accurate simulations of air–sea fluxes of heat and trace gases. Observations of the rate of dissipation of turbulent kinetic energy (ε), temperature, salinity, current structure, and wave field over a period of 9.5 days in the northeast Atlantic during the Ocean Surface Mixing, Ocean Submesoscale Interaction Study (OSMOSIS) are presented. The focus of this study is a storm that passed over the observational area during this period. The profiles of ε in the OSBL are consistent with profiles from large-eddy simulation (LES) of Langmuir turbulence. In the transition layer (TL), at the base of the OSBL, ε was found to vary periodically at the local inertial frequency. A simple bulk model of the OSBL and a parameterization of shear driven turbulence in the TL are developed. The parameterization of ε is based on assumptions about the momentum balance of the OSBL and shear across the TL. The predicted rate of deepening, heat budget, and the inertial currents in the OSBL were in good agreement with the observations, as is the agreement between the observed value of ε and that predicted using the parameterization. A previous study reported spikes of elevated dissipation related to enhanced wind shear alignment at the base of the OSBL after this storm. The spikes in dissipation are not predicted by this new parameterization, implying that they are not an important source of dissipation during the storm.