Langmuir环流在雷诺平均型模式中的参数化研究进展

Progress in parameterization of Langmuir circulation in Reynolds Average Navier-Stokes(RANS) model

Langmuir环流影响着海洋上层的能量输入,对海洋上混合层的形成和加深起着重要作用,对于海洋上混合层具有重要意义。近年来许多学者采用大涡模拟(LES)方法对Langmuir环流进行机制研究,并通过在雷诺平均模型中参数化Langmuir环流效应,将Langmuir环流过程引入到三维海洋环流或海洋耦合模式中,提出了一系列混合参数化方案。本文回顾了Langmuir环流在雷诺平均模式参数化中的研究进展,主要可分为以下几种方案:一种方法是用Langmuir数在KPP垂直混合参数化方案中引入湍流特征速度增强因子,并不断发展Langmuir数的定义;一种是在Mellor-Yamada2.5湍流闭合模型中增加斯托克斯漂流剪切效应项,此外还有通过修改模式中混合长方程来加入Langmuir效应等。通过在雷诺平均模式中应用的结果来看,现有的参数化方案在一定程度上改善了混合层深度和SST的模拟,肯定了Langmuir环流在加深混合等方面的作用,但仍存在一些问题需要在今后的研究中进一步改进。

It has been widely recognized that Langmuir circulation is one of the key factor in the formation and deepening of the mixed layer on the upper ocean.It is of great significance for the ocean mixed layer.In recent years,many researchers have used the large eddy simulation(LES)to study the Langmuir circulation mechanisms in order to find the proper parameterization of LC effect in the Reynolds average model.The Langmuir turbulence was considered into the ocean circulation or ocean coupling model,and a series of parameterization schemes were proposed.In this paper,the research advances in the research progress of Langmuir circulation parameterization in Reynolds average model,which can be divided into the several schemes:one method is parameterized by an enhancement factor applied to the turbulent velocity scale,one is to add the Stokes drift shear effect term in the Mellor-Yamada 2.5 turbulence closed model.In addition,the Langmuir effect is added by modifying the mixing length scale in the model.The existing parameterization schemes have improved the simulation of mixed layer depth and SST to some extent,affirmed the role of LC in deepening mixing,but there are still some deficiency that need to be further improved in future research.