Hail Detection and Verification Using High-Resolution Urban Radar Network over Dallas-Fort Worth

Hail is one of the major atmospheric risks threating human life and property. For example, on May 16, 2013, massive hailstorm pounded in Dallas-Fort Worth (DFW) area where several storms created hail damages running into hundreds of millions of dollars to a billion. Since early 1960s, radar has been used for hail detection based on radar reflectivity measurement. However, recent studies have shown that it is not sufficient to adequately detect and nowcast hail paths with only the radar reflectivity factor. On the other hand, the combination of dual-polarization measurements, including reflectivity (Z), differential reflectivity (Zdr), and specific differential phase (Kdp), and environmental temperature information can offer a number of advantages over traditional methods for characterizing the hail specialty because more information about the hail size distribution and shapes can be gleaned.

While the dual-polarization based hail detection scheme is well developed at S-band, the X-band implementation is rare due to practical issues such as attenuation. In this paper, we introduce the advanced hydrometeor classification methodology (Bechini and Chandrasekar 2015, J. Atmos. Oceanic Technol.) implemented for the polarimetric urban radar network deployed by the Center for Collaborative Adaptive Sensing of the Atmosphere (CASA), which consists of a network of dual-polarization X-band radars and a National Weather Service (NWS) radar operating at S-band. The high-resolution hail detection scheme is detailed, and sample operational hail products are presented. In addition, the verification based on ground hail report will be conducted from statistical perspective.