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contributor authorLi, Dan
contributor authorKatul, Gabriel G.
contributor authorZilitinkevich, Sergej S.
date accessioned2017-06-09T16:59:42Z
date available2017-06-09T16:59:42Z
date copyright2016/12/01
date issued2016
identifier issn0022-4928
identifier otherams-77596.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4220171
description abstractwo recently proposed turbulence closure schemes are compared against the conventional Mellor?Yamada (MY) model for stably stratified atmospheric flows. The Energy- and Flux-Budget (EFB) approach solves the budgets of turbulent momentum and heat fluxes and turbulent kinetic and potential energies. The Cospectral Budget (CSB) approach is formulated in wavenumber space and integrated across all turbulent scales to obtain flow variables in physical space. Unlike the MY model, which is subject to a ?critical gradient Richardson number,? both EFB and CSB models allow turbulence to exist at any gradient Richardson number and predict a saturation of flux Richardson number at sufficiently large . The CSB approach further predicts the value of and reveals a unique expression linking the Rotta and von Kármán constants. Hence, all constants in the CSB model are nontunable and stability independent. All models agree that the dimensionless sensible heat flux decays with increasing . However, the decay rate and subsequent cutoff in the MY model appear abrupt. The MY model further exhibits an abrupt cutoff in the turbulent stress normalized by vertical velocity variance, while the CSB and EFB models display increasing trends. The EFB model produces a rapid increase in the ratio of turbulent potential energy and vertical velocity variance as is approached, suggesting a strong self-preservation mechanism. Vertical anisotropy in the turbulent kinetic energy is parameterized in different ways in MY and EFB, but this consideration is not required in CSB. Differences between EFB and CSB model predictions originate from how the vertical anisotropy is specified in the EFB model.
publisherAmerican Meteorological Society
titleClosure Schemes for Stably Stratified Atmospheric Flows without Turbulence Cutoff
typeJournal Paper
journal volume73
journal issue12
journal titleJournal of the Atmospheric Sciences
identifier doi10.1175/JAS-D-16-0101.1
journal fristpage4817
journal lastpage4832
treeJournal of the Atmospheric Sciences:;2016:;Volume( 073 ):;issue: 012
contenttypeFulltext


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