The Description of Mixing in Stratified Layers without Shear in Large-Scale Ocean ModelsSource: Journal of Physical Oceanography:;2009:;Volume( 039 ):;issue: 011::page 3032Author:Umlauf, Lars
DOI: 10.1175/2009JPO4006.1Publisher: American Meteorological Society
Abstract: Large-scale geophysical flows often exhibit layers with negligible vertical shear and infinite gradient Richardson number Ri. It is well known that these layers may be regions of active mixing, even in the absence of local shear production of turbulence because, among other processes, turbulence may be supplied by vertical turbulent transport from neighboring regions. This observation is contrasted by the behavior of most turbulence parameterizations used in ocean climate modeling, predicting the collapse of mixing of mass and matter if the Richardson number exceeds a critical threshold. Here, the performance of a simple model without critical Richardson number is evaluated, taking into account the diffusion of turbulence into layers without shear production and therefore avoiding the suppression of mixing at large values of Ri. The model is based on the framework of second-moment turbulence closures, focusing on the consistent modeling of the turbulent length scale for strongly stratified turbulence. Results are compared to eddy-resolving simulations of stratified shear flows that have recently become available. The model is simple enough for inclusion in ocean climate models.
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contributor author | Umlauf, Lars | |
date accessioned | 2017-06-09T16:30:27Z | |
date available | 2017-06-09T16:30:27Z | |
date copyright | 2009/11/01 | |
date issued | 2009 | |
identifier issn | 0022-3670 | |
identifier other | ams-69104.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4210737 | |
description abstract | Large-scale geophysical flows often exhibit layers with negligible vertical shear and infinite gradient Richardson number Ri. It is well known that these layers may be regions of active mixing, even in the absence of local shear production of turbulence because, among other processes, turbulence may be supplied by vertical turbulent transport from neighboring regions. This observation is contrasted by the behavior of most turbulence parameterizations used in ocean climate modeling, predicting the collapse of mixing of mass and matter if the Richardson number exceeds a critical threshold. Here, the performance of a simple model without critical Richardson number is evaluated, taking into account the diffusion of turbulence into layers without shear production and therefore avoiding the suppression of mixing at large values of Ri. The model is based on the framework of second-moment turbulence closures, focusing on the consistent modeling of the turbulent length scale for strongly stratified turbulence. Results are compared to eddy-resolving simulations of stratified shear flows that have recently become available. The model is simple enough for inclusion in ocean climate models. | |
publisher | American Meteorological Society | |
title | The Description of Mixing in Stratified Layers without Shear in Large-Scale Ocean Models | |
type | Journal Paper | |
journal volume | 39 | |
journal issue | 11 | |
journal title | Journal of Physical Oceanography | |
identifier doi | 10.1175/2009JPO4006.1 | |
journal fristpage | 3032 | |
journal lastpage | 3039 | |
tree | Journal of Physical Oceanography:;2009:;Volume( 039 ):;issue: 011 | |
contenttype | Fulltext |