Wednesday, 5 June 2002
Experimentally measured scattering properties of plate and column ice crystals
Angular scattering properties of ice crystal clouds generated in a well developed laboratory cloud chamber are measured from a light weight nephelometer using a diode laser beam. This cloud chamber produces distinct plate and hollow column ice crystal types for light scattering experiments and provides a controlled test bed for comparison with results computed from theory. Predominate plates and hollow columns both generated noticeable 22 degree and 46 degree halo patterns that are predicted from geometric ray tracing calculations. Using the measured ice crystal shape and size distribution, the angular scattering patterns computed from geometric optics closely match those observed from the nephelometer.