Empirical estimates of CCN from aerosol optical properties at four remote sites Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder, CO, USA
NOAA Earth System Research Laboratory, Boulder, CO, USA
Received: 12 Mar 2010 – Published in Atmos. Chem. Phys. Discuss.: 08 Apr 2010Abstract. This study presents an empirical method to estimate the CCN concentration as
a function of percent supersaturation. The aerosol optical properties,
backscatter fraction and single scatter albedo, function as proxies for the
aerosol size and composition in a power law relationship to CCN. This method
is tested at four sites with aged aerosol: SGP (Oklahoma, USA), FKB (Black
Forest, Germany), HFE (Hefei, China) and GRW (Graciosa, Azores). Each site
represents a different aerosol type and thus demonstrates the method
robustness and limitations. Good agreement was found between the calculated
and measured CCN with slopes between 0.81 and 1.03 and correlation
coefficients (r2 values) between 0.59 and 0.67. The fit quality
declined at low CCN concentrations.
Revised: 14 Jun 2010 – Accepted: 06 Jul 2010 – Published: 23 Jul 2010
Citation: Jefferson, A.: Empirical estimates of CCN from aerosol optical properties at four remote sites, Atmos. Chem. Phys., 10, 6855-6861, doi:10.5194/acp-10-6855-2010, 2010.