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contributor authorZhou, Bowen;Xue, Ming;Zhu, Kefeng
date accessioned2018-01-03T11:02:38Z
date available2018-01-03T11:02:38Z
date copyright8/9/2017 12:00:00 AM
date issued2017
identifier otherjas-d-16-0376.1.pdf
identifier urihttp://138.201.223.254:8080/yetl1/handle/yetl/4246481
description abstractAbstractThe model gray zone refers to the range of grid spacings comparable to the dominant length scale of the flow. In the gray zone, the flow is partially resolved and partially subgrid scale (SGS). Neither ensemble-averaging-based parameterizations nor turbulence closures are appropriate for parameterizing the effects of SGS motions on the resolved flow. The gray zone of the convective boundary layer (CBL) is in the range of CBL depth, typically O(1) km. A new approach that seeks explicit resolution of the unstable surface layer through a nest layer of fine grid spacing is proposed to improve CBL parameterization in the gray zone. To provide the theoretical basis for the approach, a linear analytic model is presented, and one-way nested simulations are performed to investigate the dynamical coupling between the surface layer and the mixed layer. The analytic model shows that at the onset of thermal instability, the vertical and horizontal structures of the mixed layer are set by surface-layer forcings. The nested 3D simulations extend the findings from the analytic model and further reveal potential improvements in high-order statistics and resolved convective structures both including and extending above the nest region compared to the stand-alone gray-zone simulations. This study suggests that when the most energetic scales of CBL convection are resolved in the surface layer, the overall simulation of the CBL improves at gray-zone resolutions.
publisherAmerican Meteorological Society
titleA Grid-Refinement-Based Approach for Modeling the Convective Boundary Layer in the Gray Zone: A Pilot Study
typeJournal Paper
journal volume74
journal issue11
journal titleJournal of the Atmospheric Sciences
identifier doi10.1175/JAS-D-16-0376.1
journal fristpage3497
journal lastpage3513
treeJournal of the Atmospheric Sciences:;2017:;Volume( 074 ):;issue: 011
contenttypeFulltext


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