Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 15, 7585-7604, 2015
http://www.atmos-chem-phys.net/15/7585/2015/
doi:10.5194/acp-15-7585-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
13 Jul 2015
The relationship between cloud condensation nuclei (CCN) concentration and light extinction of dried particles: indications of underlying aerosol processes and implications for satellite-based CCN estimates
Y. Shinozuka1,2, A. D. Clarke3, A. Nenes4,5, A. Jefferson6,7, R. Wood8, C. S. McNaughton3,9, J. Ström10, P. Tunved10, J. Redemann11, K. L. Thornhill12, R. H. Moore13, T. L. Lathem4,14, J. J. Lin4, and Y. J. Yoon15 1NASA Ames Research Center Cooperative for Research in Earth Science and Technology, Moffett Field, California, USA
2Bay Area Environmental Research Institute, Petaluma, California, USA
3School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii, USA
4School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
5School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
6Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder, Colorado, USA
7NOAA Earth System Research Laboratory, Boulder, Colorado, USA
8Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA
9Golder Associates Ltd., Saskatoon, Saskatchewan, Canada
10Department of Applied Environmental Science, Stockholm University, Stockholm, Sweden
11NASA Ames Research Center, Moffett Field, California, USA
12Science Systems and Applications Inc., Hampton, Virginia, USA
13NASA Langley Research Center, Hampton, Virginia, USA
14Phillips 66 Research Center, Bartlesville, Oklahoma, USA
15Korea Polar Research Institute, Yeonsu-Gu, Incheon, Korea
Abstract. We examine the relationship between the number concentration of boundary-layer cloud condensation nuclei (CCN) and light extinction to investigate underlying aerosol processes and satellite-based CCN estimates. For a variety of airborne and ground-based observations not dominated by dust, regression identifies the CCN (cm−3) at 0.4 ± 0.1% supersaturation with 100.3α +1.3σ0.75 where σ (Mm−1) is the 500 nm extinction coefficient by dried particles and α is the Angstrom exponent. The deviation of 1 km horizontal average data from this approximation is typically within a factor of 2.0. ∂logCCN / ∂logσ is less than unity because, among other explanations, growth processes generally make aerosols scatter more light without increasing their number. This, barring special meteorology–aerosol connections, associates a doubling of aerosol optical depth with less than a doubling of CCN, contrary to previous studies based on heavily averaged measurements or a satellite algorithm.

Citation: Shinozuka, Y., Clarke, A. D., Nenes, A., Jefferson, A., Wood, R., McNaughton, C. S., Ström, J., Tunved, P., Redemann, J., Thornhill, K. L., Moore, R. H., Lathem, T. L., Lin, J. J., and Yoon, Y. J.: The relationship between cloud condensation nuclei (CCN) concentration and light extinction of dried particles: indications of underlying aerosol processes and implications for satellite-based CCN estimates, Atmos. Chem. Phys., 15, 7585-7604, doi:10.5194/acp-15-7585-2015, 2015.
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