The CSU-CHILL National Weather Radar Facility, located in Greeley, CO, is an advanced, transportable dual-polarized S-band weather radar system. The facility is operated by Colorado State University, under the sponsorship of the National Science Foundation and the University.
Thunderstorms extending across several Colorado counties as shown by CSU-CHILL reflectivity data collected in a 1.7 deg elevation angle PPI scan on 3 August 2013. High resolution (~1 minute scan interval) time lapse image loops documenting the evolution of the low level reflectivity and radial velocity fields in the echo area immediately southeast of the radar have been assembled.
Z - Zdr anti-correlation in an RHI scan through an ice cloud
Differential reflectivity (Zdr) values are most positive in the outer, low-reflectivity regions of an echo layer where the scatterers are mainly horizontally-oriented planar ice crystals. In the higher reflectivity regions enclosed by the yellow 14 dBZ contour, the presence of quasi-spherical hydrometeors, such as clumps of aggregated ice crystals, lowers the Zdr to ~0 dB.