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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, D02206, doi:10.1029/2004JD005694, 2006

Accumulation mode aerosol, pockets of open cells, and particle nucleation in the remote subtropical Pacific marine boundary layer

Markus D. Petters

Department of Atmospheric Science, University of Wyoming, Laramie, Wyoming, USA


Jefferson R. Snider

Department of Atmospheric Science, University of Wyoming, Laramie, Wyoming, USA


Bjorn Stevens

Department of Atmospheric Science, University of California, Los Angeles, California, USA


Gabor Vali

Department of Atmospheric Science, University of Wyoming, Laramie, Wyoming, USA


Ian Faloona

Department of Land, Air and Water Resources, University of California, Davis, California, USA


Lynn M. Russell

Scripps Institution of Oceanography, University of California, San Diego, California, USA


Abstract

We analyze a marine boundary layer cloud field encountered during the second research flight of the second Dynamics and Chemistry of Marine Stratocumulus Experiment. The cloud field is distinguished by the presence of pockets of open cells. Differences between the pockets and the surrounding stratocumulus clouds are studied utilizing in situ and satellite data. The pockets are characterized as regions where cloud radar echo tops are unusually variable, accumulation mode aerosol concentrations are low, and Aitken mode particles with a mode diameter at 0.02 μm dominate aerosol number concentration. The Aitken mode particles are thought to be generated by a nucleation event which occurred within the marine boundary layer. The low accumulation mode concentrations associated with the pockets are proposed to be necessary for their maintenance.

Received 13 December 2004; accepted 22 July 2005; published 25 January 2006.

Keywords: marine stratocumulus; aerosol-cloud interaction; CCN.

Index Terms: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801, 4906); 0320 Atmospheric Composition and Structure: Cloud physics and chemistry; 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry; 3311 Atmospheric Processes: Clouds and aerosols; 3354 Atmospheric Processes: Precipitation (1854).

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 6629264 bytes)

Citation: Petters, M. D., J. R. Snider, B. Stevens, G. Vali, I. Faloona, and L. M. Russell (2006), Accumulation mode aerosol, pockets of open cells, and particle nucleation in the remote subtropical Pacific marine boundary layer, J. Geophys. Res., 111, D02206, doi:10.1029/2004JD005694.