A Description of the CSU–CHILL National Radar Facility

The subject of this paper is the Colorado State University–University of Chicago–Illinois State Water Survey (CSU–CHILL) National Radar Facility’s S-band polarimetric research radar. Key features of this system include polarization agility (provided by the dual-transmitter, dual-receiver design), a recently updated signal processor, and a low (234 dB, two way) integrated cross-polar ratio (ICPR2) antenna system. After reviewing the technical description of the radar, the authors present a new differential reflectivity (ZDR) calibration technique and data examples collected in different polarization modes. Although the CSU–CHILL radar is transportable, it can also be operated in a dual-Doppler configuration with the CSU–Pawnee radar, an 11-cm Doppler radar system situated 48 km north of the CSU–CHILL Greeley field site. Used together, these radars provide three-dimensional kinematic and hydrometeor information in precipitating cloud systems.