Probability of Detection of SPLASH Using Polarimetric Radar

Significant research efforts have focused on discriminating hail size and distribution for a given storm. Some of the latest research has shown that storms producing large accumulations of small hail (SPLASH) have distinctive polarimetric radar signatures at S-band (e.g., significant differential attenuation and anomalously large specific differential phase, or KDP). We anticipate that these radar signatures will be useful to achieve more reliable hail size discrimination. This study further examines the characteristics of the SPLASH radar signatures to quantify how useful they can be in an operational setting. Here we test two main hypotheses: 1) the SPLASH signature will be less prominent in environments where hail melting is inhibited, resulting in very little liquid water in the radar sample volume; and 2) especially at large distances from the radar and where the melting height is lower, the Weather Surveillance Radar-1988 Doppler (WSR-88D) beam height can overshoot the SPLASH signature, limiting its detection. Moreover, we analyze over 40 SPLASH cases to determine the probability of detection (POD) and lead time utilizing the WSR-88D. Preliminary results indicate a POD of 0.90 supporting the use of SPLASH signatures for decision support services (DSS) and warning operations. In addition to the final results, we will show how these signatures can be used to provide public safety partners with potentially life saving information in an evolving DSS regime.