VOCALS Giant Cloud Condensation Nuclei (CCN) Impactor Data. Version 1.0

The NCAR/EOL/RAF Giant Cloud Condensation Nuclei Impactor (GNI) samples giant aerosol particles. This data set was acquired during the VOCALS project. Slides were exposed in the free air stream onto uncoated polycarbonate microscope slides. The slides were analyzed in the NCAR/EOL/RAF GNI slide chamber, using a dual-optical microscope. Slides were inserted into the humidified chamber with a relative humidity of 89.8 %. The images were analyzed using an automated edge detection algorithm, and using spherical cap geometry to determine the solution drop volume. Subsequently, the equivalent dry NaCl equivalent radius was determined using the Kohler equation for concentrated solutions, specifically Pruppacher and Klett, 1978, eq. 6.26b, using a full chemical potential calculation. For a detailed description, see two manuscripts in preparation by Jensen et al., available from the author.