Radar and multi-frequency Olympus beacon measurements in heavy precipitation

The authors present results obtained from two events during the summer of 1992, when radar was used to scan along the Olympus satellite path through rain and ice. Two intense precipitation events were studied with a combination of Olympus beacon measurements and a 3 GHz multipolarisation radar. Radar estimates of copolar attenuation at 3 frequencies, using only the radar-derived N₀ and D₀ parameters of a gamma DSD, have been shown to agree with measured values to within 10%. Estimates of differential attenuation at 20 GHz have been shown to be in excellent agreement too. This suggests that the drop shapes used in the inversion of radar parameters are a good representation of the effective drop shapes present in these two very different events. The behaviour of differential phase, however, shows some anomalous behaviour between the two events. It would appear that the additional effects of ice particles may be responsible for this