Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

IF value: 5.414
IF 5-year value: 5.958
IF 5-year
CiteScore value: 9.7
SNIP value: 1.517
IPP value: 5.61
SJR value: 2.601
Scimago H <br class='widget-line-break'>index value: 191
Scimago H
h5-index value: 89
Volume 13, issue 19
Atmos. Chem. Phys., 13, 9855–9867, 2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: VAMOS Ocean-Cloud-Atmosphere-Land Study (VOCALS) (ACP/OS inter-journal...

Atmos. Chem. Phys., 13, 9855–9867, 2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 07 Oct 2013

Research article | 07 Oct 2013

Microphysical process rates and global aerosol–cloud interactions

A. Gettelman1, H. Morrison1, C. R. Terai2, and R. Wood2 A. Gettelman et al.
  • 1National Center for Atmospheric Research, 1850 Table Mesa Dr., Boulder, CO 80305, USA
  • 2Department of Atmospheric Sciences, Box 351640, University of Washington, Seattle, WA 98195, USA

Abstract. Cloud microphysical process rates control the amount of condensed water in clouds and impact the susceptibility of precipitation to cloud-drop number and aerosols. The relative importance of different microphysical processes in a climate model is analyzed, and the autoconversion and accretion processes are found to be critical to the condensate budget in most regions. A simple steady-state model of warm rain formation is used to illustrate that the diagnostic rain formulations typical of climate models may result in excessive contributions from autoconversion, compared to observations and large eddy simulation models with explicit bin-resolved microphysics and rain formation processes. The behavior does not appear to be caused by the bulk process rate formulations themselves, because the steady-state model with the same bulk accretion and autoconversion has reduced contributions from autoconversion. Sensitivity tests are conducted to analyze how perturbations to the precipitation microphysics for stratiform clouds impact process rates, precipitation susceptibility and aerosol–cloud interactions (ACI). With similar liquid water path, corrections for the diagnostic rain assumptions in the GCM based on the steady-state model to boost accretion indicate that the radiative effects of ACI may decrease by 20% in the GCM. Links between process rates, susceptibility and ACI are not always clear in the GCM. Better representation of the precipitation process, for example by prognosticating precipitation mass and number, may help better constrain these effects in global models with bulk microphysics schemes.

Please read the corrigendum first before accessing the article.
Publications Copernicus
Notice on corrigendum

The requested paper has a corresponding corrigendum published. Please read the corrigendum first before downloading the article.

Final-revised paper