...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Physical Oceanography >Scaling Baroclinic Eddy Fluxes: Vortices and Energy Balance
【24h】

Scaling Baroclinic Eddy Fluxes: Vortices and Energy Balance

机译：扩展斜压涡流：涡旋和能量平衡

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

The eddy heat flux generated by the statistically equilibrated baroclinic instability of a uniform, horizontal temperature gradient is studied using a two-mode f-plane quasigeostrophic model. An overview of the dependence of the eddy diffusivity D on the bottom friction κ, the deformation radius λ, the vertical variation of the large-scale flow U, and the domain size L is provided by numerical simulations at 70 different values of the two nondimensional control parameters κλ/U and L/λ. Strong, axisymmetric, well-separated baroclinic vortices dominate both the barotropic vorticity and the temperature fields. The core radius of a single vortex is significantly larger than λ but smaller than the eddy mixing length l_(mix). On the other hand, the typical vortex separation is comparable to l_(mix). Anticyclonic vortices are hot, and cyclonic vortices are cold. The motion of a single vortex is due to barotropic advection by other distant vortices, and the eddy heat flux is due to the systematic migration of hot anticyclones northward and cold cyclones southward. These features can be explained by scaling arguments and an analysis of the statistically steady energy balance. These arguments result in a relation between D and l_(mix). Earlier scaling theories based on coupled Kolmogorovian cascades do not account for these coherent structures and are shown to be unreliable. All of the major properties of this dilute vortex gas are exponentially sensitive to the strength of the bottom drag. As the bottom drag decreases, both the vortex cores and the vortex separation become larger. Provided that l_(mix) remains significantly smaller than the domain size, then local mixing length arguments are applicable, and our main empirical result is l_(mix) ≈ 4λ exp(0.3U/κλ).
机译：使用双模f平面拟地转模型研究了由均匀平衡的水平温度梯度的统计平衡斜压不稳定性产生的涡流。涡流扩散率D对底部摩擦系数κ，变形半径λ，大流量U的垂直变化以及畴尺寸L的依赖性的概述是通过在两个无量纲的70个不同值上进行的数值模拟得出的控制参数κλ/ U和L /λ。强烈的，轴对称的，分隔良好的斜压涡旋主导着正压涡旋和温度场。一个涡旋的核心半径明显大于λ，但小于涡流混合长度l_（mix）。另一方面，典型的涡旋分离与l（混合）相当。反气旋涡很热，而气旋涡很冷。单个涡旋的运动是由于其他遥远涡流的正压平流作用，而涡流的热通量是由于热反气旋向北和冷气旋向南的系统性迁移。这些功能可以通过缩放参数和对统计稳定的能量平衡进行分析来解释。这些参数导致D和l_（mix）之间的关系。较早的基于耦合Kolmogorovian级联的缩放理论不能解释这些相干结构，因此显示是不可靠的。稀涡流气体的所有主要特性对底部阻力的强度呈指数敏感。随着底部阻力的减小，涡旋核和涡旋分离都变大。假设l_（mix）仍然显着小于域大小，则可以使用局部混合长度参数，而我们的主要经验结果是l_（mix）≈4λexp（0.3U /κλ）。

著录项

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