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

Journal metrics

Journal metrics

  • IF value: 5.414 IF 5.414
  • IF 5-year value: 5.958 IF 5-year
  • CiteScore value: 9.7 CiteScore
  • SNIP value: 1.517 SNIP 1.517
  • IPP value: 5.61 IPP 5.61
  • SJR value: 2.601 SJR 2.601
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 191 Scimago H
    index 191
  • h5-index value: 89 h5-index 89
Volume 11, issue 9
Atmos. Chem. Phys., 11, 4237–4249, 2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Atmos. Chem. Phys., 11, 4237–4249, 2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 06 May 2011

Research article | 06 May 2011

Manipulating marine stratocumulus cloud amount and albedo: a process-modelling study of aerosol-cloud-precipitation interactions in response to injection of cloud condensation nuclei

H. Wang1, P. J. Rasch1, and G. Feingold2 H. Wang et al.
  • 1Pacific Northwest National Laboratory, Atmospheric Sciences & Global Change Division, Richland, WA, USA
  • 2NOAA Earth System Research Laboratory, Chemical Sciences Division, Boulder, CO, USA

Abstract. We use a cloud-system-resolving model to study marine-cloud brightening. We examine how injected aerosol particles that act as cloud condensation nuclei (CCN) are transported within the marine boundary layer and how the additional particles in clouds impact cloud microphysical processes, and feedback on dynamics. Results show that the effectiveness of cloud brightening depends strongly on meteorological and background aerosol conditions. Cloud albedo enhancement is very effective in a weakly precipitating boundary layer and in CCN-limited conditions preceded by heavy and/or persistent precipitation. The additional CCN help sustain cloud water by weakening the precipitation substantially in the former case and preventing the boundary layer from collapse in the latter. For a given amount of injected CCN, the injection method (i.e., number and distribution of sprayers) is critical to the spatial distribution of these CCN. Both the areal coverage and the number concentration of injected particles are key players but neither one always emerges as more important than the other. The same amount of injected material is much less effective in either strongly precipitating clouds or polluted clouds, and it is ineffective in a relatively dry boundary layer that supports clouds of low liquid water path. In the polluted case and "dry" case, the CCN injection increases drop number concentration but lowers supersaturation and liquid water path. As a result, the cloud experiences very weak albedo enhancement, regardless of the injection method.

Publications Copernicus