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Published March 16, 2006 | Published + Supplemental Material
Journal Article Open

Use of in situ cloud condensation nuclei, extinction, and aerosol size distribution measurements to test a method for retrieving cloud condensation nuclei profiles from surface measurements


If the aerosol composition and size distribution below cloud are uniform, the vertical profile of cloud condensation nuclei concentration can be retrieved entirely from surface measurements of CCN concentration and particle humidification function and surface-based retrievals of relative humidity and aerosol extinction or backscatter. This provides the potential for long-term measurements of CCN concentrations near cloud base. We have used a combination of aircraft, surface in situ, and surface remote sensing measurements to test various aspects of the retrieval scheme. Our analysis leads us to the following conclusions. The retrieval works better for supersaturations of 0.1% than for 1% because CCN concentrations at 0.1% are controlled by the same particles that control extinction and backscatter. If in situ measurements of extinction are used, the retrieval explains a majority of the CCN variance at high supersaturation for at least two and perhaps five of the eight flights examined. The retrieval of the vertical profile of the humidification factor is not the major limitation of the CCN retrieval scheme. Vertical structure in the aerosol size distribution and composition is the dominant source of error in the CCN retrieval, but this vertical structure is difficult to measure from remote sensing at visible wavelengths.

Additional Information

© 2006 American Geophysical Union. Received 28 December 2004; revised 21 April 2005; accepted 19 July 2005; published 19 January 2006. This study and the May 2003 Aerosol IOP were supported by the U.S. Department of Energy Atmospheric Radiation Measurement Program and Atmospheric Science Program, which are part of the DOE Biological and Environmental Research Program. The Pacific Northwest National Laboratory is operated for the DOE by Battelle Memorial Institute under contract DE-AC06-76RLO 1830.

Attached Files

Published - 239-Ghan-2006.pdf

Supplemental Material - jgrd12051-sup-0001-t01.txt

Supplemental Material - jgrd12051-sup-0002-t02.txt

Supplemental Material - jgrd12051-sup-0003-t03.txt


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August 19, 2023
October 23, 2023