Giant Nuclei Impactor
NCAR/EOL/RAF instrument for sampling and analysis of giant aerosol particles. This data set was acquired during the VOCALS project. Slides are exposed in the free air stream onto uncoated polycarbonate microscope slides. The slides are analyzed in the NCAR/EOL/RAF GNI slide chamber using a dual-optical microscope. Slides are inserted into the humidified chamber with a relative humidity of 89.8 %. The images are 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 is 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.
Example(s) of Measurement: Microscope image from VOCALS research flight 8. The image was one of 350 images from slide 56, which was exposed at an altitude of 170 m; i.e. below a marine stratocumulus cloud deck. The wind speed was 12 m/s.