Show simple item record

contributor authorPleim, Jonathan E.
date accessioned2017-06-09T16:48:20Z
date available2017-06-09T16:48:20Z
date copyright2007/09/01
date issued2007
identifier issn1558-8424
identifier otherams-74467.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4216695
description abstractThe modeling of the atmospheric boundary layer during convective conditions has long been a major source of uncertainty in the numerical modeling of meteorological conditions and air quality. Much of the difficulty stems from the large range of turbulent scales that are effective in the convective boundary layer (CBL). Both small-scale turbulence that is subgrid in most mesoscale grid models and large-scale turbulence extending to the depth of the CBL are important for the vertical transport of atmospheric properties and chemical species. Eddy diffusion schemes assume that all of the turbulence is subgrid and therefore cannot realistically simulate convective conditions. Simple nonlocal closure PBL models, such as the Blackadar convective model that has been a mainstay PBL option in the fifth-generation Pennsylvania State University?National Center for Atmospheric Research Mesoscale Model (MM5) for many years and the original asymmetric convective model (ACM), also an option in MM5, represent large-scale transport driven by convective plumes but neglect small-scale, subgrid turbulent mixing. A new version of the ACM (ACM2) has been developed that includes the nonlocal scheme of the original ACM combined with an eddy diffusion scheme. Thus, the ACM2 is able to represent both the supergrid- and subgrid-scale components of turbulent transport in the convective boundary layer. Testing the ACM2 in one-dimensional form and comparing it with large-eddy simulations and field data from the 1999 Cooperative Atmosphere?Surface Exchange Study demonstrates that the new scheme accurately simulates PBL heights, profiles of fluxes and mean quantities, and surface-level values. The ACM2 performs equally well for both meteorological parameters (e.g., potential temperature, moisture variables, and winds) and trace chemical concentrations, which is an advantage over eddy diffusion models that include a nonlocal term in the form of a gradient adjustment.
publisherAmerican Meteorological Society
titleA Combined Local and Nonlocal Closure Model for the Atmospheric Boundary Layer. Part I: Model Description and Testing
typeJournal Paper
journal volume46
journal issue9
journal titleJournal of Applied Meteorology and Climatology
identifier doi10.1175/JAM2539.1
journal fristpage1383
journal lastpage1395
treeJournal of Applied Meteorology and Climatology:;2007:;volume( 046 ):;issue: 009
contenttypeFulltext


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record