Dual-Polarzation Radar Estimation of Rainfall Parameters Compared with Ground-Based Disdrometer Measurements: October 29, 1982 Central Illinois Expenment

Rainfall parameters estimated from dual-polarization radar measurements using the differential-reflectivity technique are compared with ground-based disdrometer measurements located 47.1 km from the radar. This case study is based on data obtained during an experiment in central Illinois on October 29, 1982. Both empirical and model relationships between radar observables and rainfall parameters ters are tested. The differential-reflectivity technique is compared with the conventional Z -R technique and is shown to provide improvements in the estimation of rainfall rate by radar. The analysis includes careful consideration of the spatial and temporal factors relating the radar-scattering volumes to the location and duration of ground-based disdrometer measurements. The significance of these factors (mainly due to the horizontal and vertical motion of raindrops) in radar-disdrometer comparisons is evident in the results.