Energy Cascades and Loss of Balance in a Reentrant Channel Forced by Wind Stress and Buoyancy Fluxes
Energy Cascades and Loss of Balance in a Reentrant Channel Forced by Wind Stress and Buoyancy Fluxes
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DOI：
10.1175/jpo-d-14-0068.1
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发表时间：
2015-01
影响因子：
3.5
通讯作者：
R. Barkan;K. Winters;S. G. L. Smith
中科院分区：
文献类型：
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作者：
R. Barkan;K. Winters;S. G. L. Smith
海洋动能的很大一部分储存在“准地转”涡旋场中。根据地转湍流理论，这种“平衡”的涡流场有望将能量传递到更大的尺度。为了使大气环流保持近似稳定，假设发生了导致失去平衡（LOB）的不稳定机制，以便涡动动能（EKE）可以转移到小尺度，在那里它可以被耗散。本研究探讨的动能路径完全解决直接数值模拟的流量在平底折返通道，外部迫使表面浮力通量和风应力的配置，类似于南极绕极流。允许流量达到统计稳定状态，在该点上，它表现出正向和反向能量级联。不规则的水深流相互作用被排除在外，使底部阻力是唯一的机制，可用于消散…
AbstractA large fraction of the kinetic energy in the ocean is stored in the “quasigeostrophic” eddy field. This “balanced” eddy field is expected, according to geostrophic turbulence theory, to transfer energy to larger scales. In order for the general circulation to remain approximately steady, instability mechanisms leading to loss of balance (LOB) have been hypothesized to take place so that the eddy kinetic energy (EKE) may be transferred to small scales where it can be dissipated. This study examines the kinetic energy pathways in fully resolved direct numerical simulations of flow in a flat-bottomed reentrant channel, externally forced by surface buoyancy fluxes and wind stress in a configuration that resembles the Antarctic Circumpolar Current. The flow is allowed to reach a statistical steady state at which point it exhibits both a forward and an inverse energy cascade. Flow interactions with irregular bathymetry are excluded so that bottom drag is the sole mechanism available to dissipate the up...