Publications

Shinozuka, Y.; Clarke, A. D.; Nenes, A.; Jefferson, A.; Wood, R.; McNaughton, C. S.; Strom, J.; Tunved, P.; Redemann, J.; Thornhill, K. L.; Moore, R. H.; Lathem, T. L.; Lin, J. J.; Yoon, Y. J. (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. ATMOSPHERIC CHEMISTRY AND PHYSICS, 15(13), 7585-7604.

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 10(0.3 alpha+1.3)sigma(0.75) where sigma (Mm(-1)) is the 500 nm extinction coefficient by dried particles and alpha is the Angstrom exponent. The deviation of 1 km horizontal average data from this approximation is typically within a factor of 2.0. partial derivative logCCN / partial derivative log sigma 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.

DOI:
10.5194/acp-15-7585-2015

ISSN:
1680-7316