Rain-Rate Estimation in the Presence of Hail Using S- Band Specific Differential Phase and Other Radar Parameters

Multiparameter radar measurements were made during a heavy rainfall event accompanied by hail in Colorado. Rainfall rates R and accumulation for this event were estimated using S-band specific differential phase KDP, reflectivity factor ZH, and X-band specific attenuation AH3. These estimates were compared with measurements from a ground-based rain gauge. Both R–KDP and R–AH3 relations were in good agreement with the rain gauge data, that is, less than 10% difference in the rainfall accumulations. The R–Z relation produced similar results only when ZH was truncated at 55 dBZ. This study demonstrates the potential of KDP for estimating rainfall rates in severe storms that may have rain-hail mixtures. 404 $OURNAL OF APPLIED METEOROLOGY VOLUME34 Rain-Rate Estimation in the Presence of Hail Using S-Band Specific Differential Phase and Other Radar Parameters K.. AYDIN Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania V. N. BRING1 AND L. LIU Department of Electrical Engineering, Colorado State University, Fort Collins, Colorado (Manuscript received 21 February 1994, in final form 23 June 1994) ABSTRACT Multiparameter radar measurements were made during a heavy rainfall event accompanied by hail in Colorado. Rainfall rates R and accumulation Z for this event were estimated using S-band specific differential phase KDp, reflectivity factor Zn, and X-band specific attenuation Am. These estimates were compared with measurements from a ground-based rain gauge. Both R-Kv~, and R-Am relations were in good agreement with the rain gauge data, that is, less than 10% difference in the rainfall accumulations. The R-Z relation produced similar results only when ZH was truncated at 55 dBZ. This study demonstrates the potential of KDp for estimating rainfall rates in severe storms that may have rain-hall mixtures.