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Title: Aerosol specification in single-column Community Atmosphere Model version 5

Abstract

Single-column model (SCM) capability is an important tool for general circulation model development. In this study, the SCM mode of version 5 of the Community Atmosphere Model (CAM5) is shown to handle aerosol initialization and advection improperly, resulting in aerosol, cloud-droplet, and ice crystal concentrations which are typically much lower than observed or simulated by CAM5 in global mode. This deficiency has a major impact on stratiform cloud simulations but has little impact on convective case studies because aerosol is currently not used by CAM5 convective schemes and convective cases are typically longer in duration (so initialization is less important). By imposing fixed aerosol or cloud-droplet and crystal number concentrations, the aerosol issues described above can be avoided. Sensitivity studies using these idealizations suggest that the Meyers et al. (1992) ice nucleation scheme prevents mixed-phase cloud from existing by producing too many ice crystals. Microphysics is shown to strongly deplete cloud water in stratiform cases, indicating problems with sequential splitting in CAM5 and the need for careful interpretation of output from sequentially split climate models. Droplet concentration in the general circulation model (GCM) version of CAM5 is also shown to be far too low (~ 25 cm −3) at themore » southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) site.« less

Authors:
;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1197696
Grant/Contract Number:  
DOE award 33871/SCW1316-BER
Resource Type:
Journal Article: Published Article
Journal Name:
Geoscientific Model Development (Online)
Additional Journal Information:
Journal Name: Geoscientific Model Development (Online) Journal Volume: 8 Journal Issue: 3; Journal ID: ISSN 1991-9603
Publisher:
European Geosciences Union
Country of Publication:
Germany
Language:
English

Citation Formats

Lebassi-Habtezion, B., and Caldwell, P. M. Aerosol specification in single-column Community Atmosphere Model version 5. Germany: N. p., 2015. Web. doi:10.5194/gmd-8-817-2015.
Lebassi-Habtezion, B., & Caldwell, P. M. Aerosol specification in single-column Community Atmosphere Model version 5. Germany. doi:10.5194/gmd-8-817-2015.
Lebassi-Habtezion, B., and Caldwell, P. M. Fri . "Aerosol specification in single-column Community Atmosphere Model version 5". Germany. doi:10.5194/gmd-8-817-2015.
@article{osti_1197696,
title = {Aerosol specification in single-column Community Atmosphere Model version 5},
author = {Lebassi-Habtezion, B. and Caldwell, P. M.},
abstractNote = {Single-column model (SCM) capability is an important tool for general circulation model development. In this study, the SCM mode of version 5 of the Community Atmosphere Model (CAM5) is shown to handle aerosol initialization and advection improperly, resulting in aerosol, cloud-droplet, and ice crystal concentrations which are typically much lower than observed or simulated by CAM5 in global mode. This deficiency has a major impact on stratiform cloud simulations but has little impact on convective case studies because aerosol is currently not used by CAM5 convective schemes and convective cases are typically longer in duration (so initialization is less important). By imposing fixed aerosol or cloud-droplet and crystal number concentrations, the aerosol issues described above can be avoided. Sensitivity studies using these idealizations suggest that the Meyers et al. (1992) ice nucleation scheme prevents mixed-phase cloud from existing by producing too many ice crystals. Microphysics is shown to strongly deplete cloud water in stratiform cases, indicating problems with sequential splitting in CAM5 and the need for careful interpretation of output from sequentially split climate models. Droplet concentration in the general circulation model (GCM) version of CAM5 is also shown to be far too low (~ 25 cm−3) at the southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) site.},
doi = {10.5194/gmd-8-817-2015},
journal = {Geoscientific Model Development (Online)},
number = 3,
volume = 8,
place = {Germany},
year = {Fri Mar 27 00:00:00 EDT 2015},
month = {Fri Mar 27 00:00:00 EDT 2015}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.5194/gmd-8-817-2015

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Cited by: 2 works
Citation information provided by
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