Airborne CoSMIR Observations Between 50 and 183 GHz Over Snow-Covered Sierra Mountains

An airborne Conical Scanning Millimeter-wave Imaging Radiometer (CoSMIR) was developed recently for calibration/validation of the new-generation DMSP F-series microwave radiometer, the Special Sensor Microwave/Imager/Sounder. The CoSMIR is a total-power radiometer that measures radiation at nine channels over the frequency range of 50–183 GHz. The instrument employs a two-axis gimbaled mechanism to generate the conical scan with periodic calibration. Its scan geometry is software programmable and can be designed to serve the scientific requirements of an experiment. A series of CoSMIR flights was conducted over the coastal regions of California in March and December of 2004, in which the instrument was programmed to acquire both conical and across-track scan data sets simultaneously. Two of these flights on March 25 and December 2 contained segments over the snow-covered Sierra Mountain Range and were selected to demonstrate the novel features of this new instrument.