Development and Evaluation of Trajectory-Insensitive Particle Measurement Methods for Icing Cloud Characterization

Droplet size, LWC, and temperature are the primary parameters in icing. Numerical models and algorithms have been developed to correlate LWC, temperature, and droplet size values with different icing types and severity. However, these algorithms and models are in early stage development and need extensive testing. Reliable measurements of cloud droplet spectra as well as droplet dynamics are a key to these development efforts. The need to characterize mixed phase clouds suggests the combined use of imaging techniques to obtain information on particle shape allowing droplets to be discriminated from ice crystals and other particles. A cloud mapping system has been proposed. It consists of a PDI (phase Doppler interferometer) probe and an HSI (high speed imaging) probe, and is capable of time resolved measurements of drop size distributions, LWC, and particle concentration that will provide cloud characteristics as a function of time and location in the clouds. Acceptance of this new system will require the careful evaluation of the measurements methods, extensive comparisons to the established results, and reconciliation of any differences in the measurements.