Accuracy of reflectivity estimated from profiling radars

In this study, the accuracy of reflectivity measured using vertically pointing profiling radars is investigated. Interesting, while disdrometer observations are used to absolutely calibrate profiling radars, this study quantifies that disdrometers have significantly larger random measurement uncertainty than profiling radars. Using observations from a S-band profiling radar during the tropical warm pool international cloud experiment (TWPICE), reflectivity uncertainties of rainfall were found to be about 0.25 dBZ for 9-second dwell times and about 0.1 dBZ for 60-second dwell times. It was also found that the reflectivity uncertainty was dependent on both the signal-to-noise ratio and the number of velocity channels in the Doppler velocity power spectrum above the noise threshold. This lead to the reflectivity uncertainty for snow which has narrower velocity spectra than rain to increase to 0.4 and 0.2 dBZ for 9- and 60-second dwell times, respectively.