A Dual-Wavelength Airborne Radar for Remote Detection of Icing Conditions

General aviation and commuter aircraft generally do not have adequate deicing equipment to operate safely in all types of icing conditions. Since icing forecasts are not yet sufficiently reliable for pilots to avoid icing conditions, an airborne system that remotely detects icing conditions ahead of the aircraft could prevent serious accidents. The National Oceanic and Atrmospheric Administration Environmental Technologies Laboratories (NOAA/ETL) tested a prototype, dual-wavelength radar system for measuring cloud liquid water content during the Winter Icing and Storms Project (WISP) in 1991. The results were encouraging, but some hardware problems, such as mis-matched sample volumes, prevented the experiment from being conclusive. In Phase I, we will conduct further tests of a similar dual-wavelength radar system which has been modified to match the radar sample volumes. The tests will be conducted at the Mt. Washington Observatory, renown for its persistent icing conditions. The radar measurements will be compared with simultaneous in situ measurements of cloud liquid water content made by state-of-the-art instrumentation. Based on the results of the field test, we will design a custom FMCW radar system with increased sensitivity for flight tests planned in Phase II. A compact, airborne radar system that provides remote detection of thunderstorms, Doppler wind-shear and icing conditions would be extremely valuable for general aviation, commuter aircraft and jet transport aircraft. In addition, a ground-based radar system capable of detecting icing conditions would be in demand at major airports all over the world.