Classification of Rain Regimes by the Three-Dimensional Properties of Reflectivity Fields

Abstract An automated scheme to characterize precipitation echoes within small windows in the radar field is presented and applied to previously subjectively classified tropical rain cloud systirns near Darwin, Australia. The classification parameters are (a) Ee, effective efficiency, as determined by cloud-top and cloud-base water vaporsaturation mixing ratios; (b) BBF, brightband fraction, as determined by the fraction of the radar echo area in which the maximal reflectivity occurs within +1.5 km of the 0C isotherm level; and (c) ΔrZ, radial reflectivity gradients (dB km-1). These classification criteria were applied to tropical rain cloud systems near Darwin, Australia, and to winter convective rain cloud systems in Israel. Both sets of measurements were made with nearly identical networks of C-band radars and rain gauge networks. The results of the application of these objective classification criteria to several independently predetermined rain regimes in Darwin have shown that better organized rain ...