Supercell polarimetric signatures at X-band: Data from VORTEX2

Data obtained from three supercell thunderstorms during the Verification of the Origins of Rotation in Tornadoes EXperiment, Part 2 (VORTEX2) by the NOAA (NSSL) X-band Polarized (NOXP) mobile weather radar are investigated. The 5 June and 7 June 2009 supercells and the 10 May 2010 supercell are analyzed in an attempt to quantify previously noted C- (5 cm wavelength) and S-band (10 cm wavelength) dual-polarimetric signatures such as the tornadic debris signature (TDS), the updraft signature, the hail signature, the ZDR arc, ZDR and KDP columns, Rhv and ZDR rings, as seen at X-band (3-cm wavelength). However, attenuation and differential attenuation limit observations of reflectivity and dual-polarization signatures at X-band. The ZPHI Rain-Profiling algorithm and Gamma method are applied to mitigate attenuation and differential attenuation in an attempt to correct the data and better identify signatures in regions of the supercell thunderstorms. An important finding for the 5 June and 7 June cases is that a distinct large hail signature is detected through significant reductions of Rhv, near zero ZDR, moderate ZH, and even negative KDP at X-band. The location of the hail signature is seen to vary some between cases. Another finding for all three cases is that no hail is observed within the hook echoes, only rain of varying drop diameters. Also, many of the observed X-band polarimetric signatures vary rapidly with time, even though time resolution for features is only 2 minutes.