Liquid cloud measurements with an airborne W-band radar and G-band radiometer system

The National Research Council of Canada (NRC), in cooperation with ProSensing Inc., developed a state-of-the-art dual frequency airborne radar system for atmospheric and flight safety research for its Convair-580 research aircraft. The NRC Airborne W and X-band (NAWX) radar system has polarimetric and Doppler capabilities at both wavelengths and can switch electronically between zenith, nadir and side looking antennas. Using a motorized reflector plate, the zenith W-band antenna is also be able to scan -5° aft to +45° forward in horizontal and vertical directions, to provide dual-Doppler capability in the side and nadir directions at W-band. In early 2007 the new NAWX radar system, along with a pod mounted G-band water Vapor Radiometer (GVR) developed by ProSensing Inc., was installed on the NRC Convair-580 aircraft, as shown in Figure 1, and participated in the Canadian CloudSat and CALIPSO validation flights. Liquid cloud data collected with the Zenith pointed W-band radar and G-band radiometer, complemented with aircraft in-situ probes, provided an opportunity to develop and test radar/radiometer algorithms for the estimation of liquid cloud properties. This paper will describe the NAWX radar and GVR radiometer, the aircraft installation, the CloudSat validation flights and initial results of liquid cloud particle size and concentration estimates from the radar and radiometer data.