论文标题
一种新的混合质量液液/高阶湍流闭合,用于海洋垂直混合
A new hybrid mass-flux/ high-order turbulence closure for ocean vertical mixing
论文作者
论文摘要
尽管已经提出了不同级别的复杂性垂直湍流的各种参数化,但每个参数都有其自身的局限性。例如,简单的一阶封闭方案(例如K-Profile参数化(KPP))缺乏能量约束。 $ k-ε$(例如$ k-ε$)直接求解湍流动能的方程式,但不考虑非本地通量,包括非本地传输项在内的高阶封闭在计算上很昂贵。为了解决这些问题,在这里,我们扩展了最初为大气边界层提出的假定分布高阶闭合(ADC)框架,并将其应用于海面边界层(OSBL)。通过假设垂直速度和示踪剂之间的概率分布函数关系,所有二阶和高阶矩都是精确构造的,并且在ADC方案中实现了湍流闭合。另外,ADC参数化方案具有完整的能量约束。我们已经测试了ADC方案,用于用于表面浮力驱动的对流混合的大型涡流模拟(LES),KPP和$ K-ε$的组合,发现ADC方案具有不同的垂直分辨率,并且与LES结果进行了很好的比较。
While various parameterizations of vertical turbulent fluxes at different levels of complexity have been proposed, each has its own limitations. For example, simple first-order closure schemes such as the K-Profile Parameterization (KPP) lack energetic constraints; two-equation models like $k-ε$ directly solve an equation for the turbulent kinetic energy but do not account for non-local fluxes, and high-order closures that include the non-local transport terms are computationally expensive. To address these, here we extend the Assumed-Distribution Higher-Order Closure (ADC) framework originally proposed for the atmospheric boundary layer and apply it to the ocean surface boundary layer (OSBL). By assuming a probability distribution function relationship between the vertical velocity and tracers, all second-order and higher-order moments are exactly constructed and turbulence closure is achieved in the ADC scheme. In addition, the ADC parameterization scheme has full energetic constraints. We have tested the ADC scheme against a combination of large eddy simulation (LES), KPP, and $k-ε$ for surface buoyancy-driven convective mixing and found that the ADC scheme is robust with different vertical resolutions and compares well to the LES results.