Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus clouds

To model stratocumulus clouds in the regional climate model, RegCM4.1, the University of Washington (UW) turbulence parametrization has been coupled to RegCM. We describe improvements in RegCM's coastal and near-coastal climatology, including improvements in the representation of stratiform clo...

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Main Authors: T. A. O'Brien, P. Y. Chuang, L. C. Sloan, I. C. Faloona, D. L. Rossiter
Format: Article
Language:English
Published: Copernicus Publications 2012-08-01
Series:Geoscientific Model Development
Online Access:http://www.geosci-model-dev.net/5/989/2012/gmd-5-989-2012.pdf
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author T. A. O'Brien
P. Y. Chuang
L. C. Sloan
I. C. Faloona
D. L. Rossiter
author_facet T. A. O'Brien
P. Y. Chuang
L. C. Sloan
I. C. Faloona
D. L. Rossiter
author_sort T. A. O'Brien
collection DOAJ
description To model stratocumulus clouds in the regional climate model, RegCM4.1, the University of Washington (UW) turbulence parametrization has been coupled to RegCM. We describe improvements in RegCM's coastal and near-coastal climatology, including improvements in the representation of stratiform clouds. By comparing output from a 27-yr (1982–2009) simulation of the climate of western North America to a wide variety of observational data (station data, satellite data, and aircraft in situ data), we show the following: (1) RegCM-UW is appropriate for use in general regional climate studies, and (2) the UW model distinctly improves the representation of the marine boundary layer in RegCM. These model–data comparisons also show that RegCM-UW has a slight cold bias, a (wet) precipitation bias, a systematic low bias in the vertically-integrated liquid water content near the coast, and a high bias in the fractional cloud coverage. The model represents well the diurnal, monthly, and interannual variability in low clouds. These results show RegCM-UW as a nascent mesoscale stratocumulus model that is appropriate for stratocumulus investigations at scales ranging from hourly to decadal. The source code for RegCM-UW is publicly available, under the GNU license, through the International Centre for Theoretical Physics.
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spelling doaj.art-644dd7f852664bdda2b7e59718134e362022-12-22T01:08:03ZengCopernicus PublicationsGeoscientific Model Development1991-959X1991-96032012-08-0154989100810.5194/gmd-5-989-2012Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus cloudsT. A. O'BrienP. Y. ChuangL. C. SloanI. C. FaloonaD. L. RossiterTo model stratocumulus clouds in the regional climate model, RegCM4.1, the University of Washington (UW) turbulence parametrization has been coupled to RegCM. We describe improvements in RegCM's coastal and near-coastal climatology, including improvements in the representation of stratiform clouds. By comparing output from a 27-yr (1982–2009) simulation of the climate of western North America to a wide variety of observational data (station data, satellite data, and aircraft in situ data), we show the following: (1) RegCM-UW is appropriate for use in general regional climate studies, and (2) the UW model distinctly improves the representation of the marine boundary layer in RegCM. These model–data comparisons also show that RegCM-UW has a slight cold bias, a (wet) precipitation bias, a systematic low bias in the vertically-integrated liquid water content near the coast, and a high bias in the fractional cloud coverage. The model represents well the diurnal, monthly, and interannual variability in low clouds. These results show RegCM-UW as a nascent mesoscale stratocumulus model that is appropriate for stratocumulus investigations at scales ranging from hourly to decadal. The source code for RegCM-UW is publicly available, under the GNU license, through the International Centre for Theoretical Physics.http://www.geosci-model-dev.net/5/989/2012/gmd-5-989-2012.pdf
spellingShingle T. A. O'Brien
P. Y. Chuang
L. C. Sloan
I. C. Faloona
D. L. Rossiter
Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus clouds
Geoscientific Model Development
title Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus clouds
title_full Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus clouds
title_fullStr Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus clouds
title_full_unstemmed Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus clouds
title_short Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus clouds
title_sort coupling a new turbulence parametrization to regcm adds realistic stratocumulus clouds
url http://www.geosci-model-dev.net/5/989/2012/gmd-5-989-2012.pdf
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