Millimeter- and Submillimeter-Wave Differential Absorption Radar

The Jet Propulsion Laboratory is developing two experimental Differential Absorption Radar (DAR) platforms for remote sensing of water vapor on both Earth and planetary bodies. These are VIPR (Vapor Inside-cloud Profiling Radar), which operates near the 183 GHz water absorption resonance, and WASSR (WAter Sounding Short-range Radar), tuned to the 557 GHz water line. Here we contrast the system architecture for the two experimental instruments and present preliminary results of VIPR's recent airborne deployment.