Parameterization of mixed layer eddies. Part I: Theory and diagnosis
Parameterization of mixed layer eddies. Part I: Theory and diagnosis
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DOI：
10.1175/2007jpo3792.1
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发表时间：
2008-06-01
影响因子：
3.5
通讯作者：
Hallberg, Robert
中科院分区：
文献类型：
--
作者：
Fox-Kemper, Baylor;Ferrari, Raffaele;Hallberg, Robert
非地转斜压不稳定在水平锋的海洋表面混合层中发展，并有效地抑制了上层海洋。本文提出了一个由混合层有限振幅斜压不稳定性驱动的约束参数化，它是用一个使等密度线从垂直向水平倾斜的翻转流函数来表示的。流函数与水平密度梯度、混合层深度平方和惯性周期的乘积成正比。因此，在深度混合层中，强锋面的非限制化进行得更快，而纬度依赖性较弱。在本文中，参数化的理论动机，证实了广泛的混合层深度，旋转速率，垂直和水平分层执行。对于混合层限制问题，它比现有的斜压不稳定参数化方案有上级的优越性。两个配套文件讨论的数值实施和气候影响的参数化。
Ageostrophic baroclinic instabilities develop within the surface mixed layer of the ocean at horizontal fronts and efficiently restratify the upper ocean. In this paper a parameterization for the restratification driven by finite-amplitude baroclinic instabilities of the mixed layer is proposed in terms of an overturning streamfunction that tilts isopycnals from the vertical to the horizontal. The streamfunction is proportional to the product of the horizontal density gradient, the mixed layer depth squared, and the inertial period. Hence restratification proceeds faster at strong fronts in deep mixed layers with a weak latitude dependence. In this paper the parameterization is theoretically motivated, confirmed to perform well for a wide range of mixed layer depths, rotation rates, and vertical and horizontal stratifications. It is shown to be superior to alternative extant parameterizations of baroclinic instability for the problem of mixed layer restratification. Two companion papers discuss the numerical implementation and the climate impacts of this parameterization.