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Title: Model simulations of aerosol effects on clouds and precipitation in comparison with ARM data

Abstract

Observation-based studies have shown that the aerosol cloud lifetime effect or the increase of cloud liquid water path (LWP) with increased aerosol loading may have been overestimated in climate models. Here, we simulate shallow warm clouds on 05/27/2011 at the Southern Great Plains (SGP) measurement site established by Department of Energy's Atmospheric Radiation Measurement (ARM) Program using a single column version of a global climate model (Community Atmosphere Model or CAM) and a cloud resolving model (CRM). The LWP simulated by CAM increases substantially with aerosol loading while that in the CRM does not. The increase of LWP in CAM is caused by a large decrease of the autoconversion rate when cloud droplet number increases. In the CRM, the autoconversion rate is also reduced, but this is offset or even outweighed by the increased evaporation of cloud droplets near cloud top, resulting in an overall decrease in LWP. Our results suggest that climate models need to include the dependence of cloud top growth and the evaporation/condensation process on cloud droplet number concentrations.

Authors:
 [1];  [1]
  1. Univ. of Michigan, Ann Arbor, MI (United States)
Publication Date:
Research Org.:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1338906
Report Number(s):
DOE-Michigan-08486
DOE Contract Number:  
SC0008486
Resource Type:
Technical Report
Resource Relation:
Related Information: Zhou, C. and J. E. Penner, 2017: Why do GCMs overestimate the aerosol cloud lifetime effect? A case study comparing CAM5 and a CRM, Atmos. Chem. Phys., 17, 21–29, doi:10.5194/acp-17-21-2017.
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; climate models; aerosol indirect effects

Citation Formats

Penner, Joyce E., and Zhou, Cheng. Model simulations of aerosol effects on clouds and precipitation in comparison with ARM data. United States: N. p., 2017. Web. doi:10.2172/1338906.
Penner, Joyce E., & Zhou, Cheng. Model simulations of aerosol effects on clouds and precipitation in comparison with ARM data. United States. doi:10.2172/1338906.
Penner, Joyce E., and Zhou, Cheng. Thu . "Model simulations of aerosol effects on clouds and precipitation in comparison with ARM data". United States. doi:10.2172/1338906. https://www.osti.gov/servlets/purl/1338906.
@article{osti_1338906,
title = {Model simulations of aerosol effects on clouds and precipitation in comparison with ARM data},
author = {Penner, Joyce E. and Zhou, Cheng},
abstractNote = {Observation-based studies have shown that the aerosol cloud lifetime effect or the increase of cloud liquid water path (LWP) with increased aerosol loading may have been overestimated in climate models. Here, we simulate shallow warm clouds on 05/27/2011 at the Southern Great Plains (SGP) measurement site established by Department of Energy's Atmospheric Radiation Measurement (ARM) Program using a single column version of a global climate model (Community Atmosphere Model or CAM) and a cloud resolving model (CRM). The LWP simulated by CAM increases substantially with aerosol loading while that in the CRM does not. The increase of LWP in CAM is caused by a large decrease of the autoconversion rate when cloud droplet number increases. In the CRM, the autoconversion rate is also reduced, but this is offset or even outweighed by the increased evaporation of cloud droplets near cloud top, resulting in an overall decrease in LWP. Our results suggest that climate models need to include the dependence of cloud top growth and the evaporation/condensation process on cloud droplet number concentrations.},
doi = {10.2172/1338906},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 12 00:00:00 EST 2017},
month = {Thu Jan 12 00:00:00 EST 2017}
}

Technical Report:

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