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© 2014. This work is published under http://creativecommons.org/licenses/by-nc-nd/3.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Aerosol-climate interactions constitute one of the major sources of uncertainty in assessing changes in aerosol forcing in the anthropocene as well as understanding glacial-interglacial cycles. Here we focus on improving the representation of mineral dust in the Community Atmosphere Model and assessing the impacts of the improvements in terms of direct effects on the radiative balance of the atmosphere. We simulated the dust cycle using different parameterization sets for dust emission, size distribution, and optical properties. Comparing the results of these simulations with observations of concentration, deposition, and aerosol optical depth allows us to refine the representation of the dust cycle and its climate impacts. We propose a tuning method for dust parameterizations to allow the dust module to work across the wide variety of parameter settings which can be used within the Community Atmosphere Model. Our results include a better representation of the dust cycle, most notably for the improved size distribution. The estimated net top of atmosphere direct dust radiative forcing is −0.23 ± 0.14 W/m2 for present day and −0.32 ± 0.20 W/m2 at the Last Glacial Maximum. From our study and sensitivity tests, we also derive some general relevant findings, supporting the concept that the magnitude of the modeled dust cycle is sensitive to the observational data sets and size distribution chosen to constrain the model as well as the meteorological forcing data, even within the same modeling framework, and that the direct radiative forcing of dust is strongly sensitive to the optical properties and size distribution used.

Details

Title
Improved dust representation in the Community Atmosphere Model
Author
Albani, S 1 ; Mahowald, N M 2 ; Perry, A T 2 ; Scanza, R A 2 ; Zender, C S 3 ; Heavens, N G 4 ; Maggi, V 5 ; Kok, J F 6 ; Otto-Bliesner, B L 7 

 Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, New York, USA; Department of Environmental Sciences, University of Milano-Bicocca, Milano, Italy 
 Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, New York, USA 
 Department of Earth System Science, University of California, Irvine, California, USA 
 Department of Atmospheric and Planetary Sciences, Hampton University, Hampton, Virginia, USA 
 Department of Environmental Sciences, University of Milano-Bicocca, Milano, Italy 
 Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, New York, USA; Now at Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California, USA 
 National Center for Atmospheric Research, Boulder, Colorado, USA 
Pages
541-570
Section
Research Articles
Publication year
2014
Publication date
Sep 2014
Publisher
John Wiley & Sons, Inc.
e-ISSN
19422466
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1917745725
Copyright
© 2014. This work is published under http://creativecommons.org/licenses/by-nc-nd/3.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.