A new narrowbeam, multi-frequency scanning radiometer and its applications to in-flight icing detection

A narrow-beam (1 degree beamwidth), multi-channel (20-30 and 89 GHz), polarized (89 vertical and horizontal) radiometer with full azimuthal and elevational scanning capabilities has been built with the purpose of improving the detection of in-flight icing hazards to aircraft in the near airport environment. This goal was achieved by co-locating the radiometer with Colorado State University's CHILL polarized Doppler radar and taking advantage of similar beamwidth and volume scan regiments. In this way, the liquid water path and water vapor measurements derived from the radiometer were merged with CHILL's moment fields to provide diagnoses of water phase and microphysics aloft. The radiometer was field tested at Colorado State University's CHILL radar site near Greeley, Colorado during the summer of 2009. Instrument design, calibration and initial field testing results are discussed in this paper.