...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Physical Oceanography >Friction and Diapycnal Mixing at a Slope: Boundary Control of Potential Vorticity
【24h】

Friction and Diapycnal Mixing at a Slope: Boundary Control of Potential Vorticity

机译：斜面上的摩擦和斜向混合：潜在涡度的边界控制

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Although atmospheric forcing by wind stress or buoyancy flux is known to change the ocean's potential vorticity (PV) at the surface, less is understood about PV modification in the bottom boundary layer. The adjustment of a geostrophic current over a sloped bottom in a stratified ocean generates PV sources and sinks through friction and diapycnal mixing. The time-dependent problem is solved analytically for a no-slip boundary condition, and scalings are identified for the change in PV that arises during the adjustment to steady state. Numerical experiments are run to test the scalings with different turbulent closure schemes. The key parameters that control whether PV is injected into or extracted from the fluid are the direction of the geostrophic current and the ratio of its initial speed to its steady-state speed. When the current is in the direction of Kelvin wave propagation, downslope Ekman flow adverts lighter water under denser water, driving diabatic mixing and extracting PV. For a current in the opposite direction, Ekman advection tends to restratify the bottom boundary layer and increase the PV. Mixing near the bottom counteracts this restratification, however, and an increase in PV will only occur for current speeds exceeding a critical value. Consequently, the change in PV is asymmetric for currents of the opposite sign but the same speed, with a bias toward PV removal. In the limit of a large speed ratio, the change in PV is independent of diapycnal mixing.
机译：尽管已知由风应力或浮力通量引起的大气强迫会改变海洋在表面的潜在涡度（PV），但对底部边界层中的PV改性了解得很少。分层海洋中倾斜底部上的地转流的调节产生PV源，并通过摩擦和斜向混合而下沉。对于无滑移边界条件，可以解决与时间有关的问题，并为在调整到稳态期间出现的PV变化确定标度。进行数值实验以测试具有不同湍流闭合方案的水垢。控制PV是注入流体中还是从流体中提取PV的关键参数是地转流的方向及其初始速度与稳态速度之比。当电流沿开尔文波传播方向流动时，下坡埃克曼流将较轻的水吸引到较稠密的水之下，从而推动绝热混合并提取PV。对于相反方向的电流，Ekman对流往往会重新调整底部边界层并增加PV。但是，底部附近的混合会抵消这种重新平衡，并且仅当电流速度超过临界值时，PV才会增加。因此，对于符号相反但速度相同的电流，PV的变化是不对称的，并且偏向于PV去除。在大速比的极限下，PV的变化与二面体混合无关。

著录项

  • 来源
    《Journal of Physical Oceanography》 |2012年第9期|p.1509-1523|共15页
  • 作者

    Jessica Benthuysen; Leif N. Thomas;

  • 作者单位

    Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program, Woods Hole, Massachusetts, and CSIRO Marine and Atmospheric Research, and Centre for Australian Weather and Climate Research, Hobart, Tasmania, Australia,;

    Department of Environmental Earth System Science, Stanford University, Stanford, California;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号