Closure Study of Modeled and Measured Cloud Condensation Nuclei During CLASIC 2007

A Differential Mobility Analyzer/Tandem Differential Mobility Analyzer (DMA/TDMA) was operated aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter during The Cloud and Land Surface Interaction Campaign (CLASIC) in June of 2007 to characterize the size-resolved concentration and hygroscopicity of the submicron aerosol. A Droplet Measurement Technologies (DMT) Cloud Condensation Nuclei Counter (CCNc) was also operated on the aircraft to measure the concentration of CCN active at supersaturations of 0.165, 0.305, and 0.60 %. The campaign included 14 research flights designed to study how land surface processes affect atmospheric aerosol loading and chemistry and the resulting effects on the microphysical and macrophysical properties of cumulus cloud fields. Over 1300 size distributions were measured along with 110 hygroscopic growth factor distributions for each dry diameter of 0.025, 0.050, 0.100, 0.200, and 0.400 micrometer. The CCN number concentration at each specified supersaturation was predicted from the combined size-resolved concentration and hygroscopicity measurements. Here we present a comparison of the predicted concentrations with those directly measured with the CCNc.