Cloud Dynamics Revealed by a G-band Humidity-Sounding Differential Absorption Radar

VIPR, Vapor Inside-cloud Profiling Radar, is a low peak power cloud radar operating over 167-174.8 GHz, which is on the flank of the 183 GHz water vapor absorption line. VIPR's primary purpose is to measure absolute humidity by using the frequency dependence of water vapor absorption along the radar beam's path. Here we describe an additional capability of VIPR, which is to reveal internal cloud dynamics from the power ratio of range compressed spectra from long-duration linear-frequency-modulated pulses with opposite chirp directions. While the measurements are qualitative, relying on differences of incoherently averaged cloud reflectivity that arise from the Doppler-shift induced range migration of spatial reflectivity gradients, we show that they can reveal the location of wind shear in a cloud system.