Preliminary Results from the Multi-Angle Snowflake Camera and Radar (MASCRAD) Project

The MASCRAD (Multi-Angle Snowflake Camera and Radar) project was conducted in northeastern Colorado during the November 2014 – April 2015 period. The overall goal of this project was to collect observations of winter season hydrometeors with enough detail to initialize electromagnetic scattering model calculations. Dual-polarization data collected by the CSU-CHILL and NCAR S-Pol radars provided external references for the scattering model results.

The hydrometeor observations were made at a ground instrumentation site established at a range of 13 km from the CSU-CHILL radar near Greeley, Colorado. A primary instrument installed at this site was a multi-angle snowflake camera (MASC) developed at the University of Utah. In this project, the MASC had an array of five digital cameras (three original MASC cameras plus two cameras added by the project team) to obtain images of snow particles larger than ~1 mm in diameter from multiple viewing directions. These individual images were combined to develop detailed three-dimensional representations of hydrometeor structure in terms of air/ice arrangements, degree of riming, etc. Supporting precipitation observations were made by a 2D video disdrometer and a strain gauge type total precipitation sensor. During the final phases of the project, a droplet spectrometer was also added at the ground instrumentation site.

This paper will present preliminary results from several events observed during MASCRAD 2014/2015 winter campaign that involved contrasting hydrometeor forms. Of particular interest were episodes when the occurrence of vertically-oriented graupel, pristine individual ice crystals, and large-diameter aggregates were documented. The dual-polarization radar observations and selected scattering model results from these events will be shown.