Detection of electrification with the co-to-cross correlation coefficient with storm microphysics analysis

As convective storms develop and become electrified, typically many ice crystals are produced. These ice crystals can become aligned by the electric field and obtain a mean canting angle that is away from the horizontal. Without electrification, ice crystals will align themselves horizontally due to aerodynamic forces, unless the ice crystals are very small (<30 microns with Brownian motion). If these ice crystals are in high enough concentrations, polarimetric radar can detect them with several variables. Previous authors have identified canted ice crystals with differential phase (φdp) and LDR (Linear Depolarization Ratio). Here we demonstrate how these ice crystals are detected using the co-to-cross correlation coefficient (ρx). Using ρx, φdp, LDR and Zdr, inferences about the ice microphysics and cloud charge structure can be deduced. The theoretical analysis is supported with experimental measurements from S-Pol, NCAR's (National Center of Atmospheric Research) S-band polarimetric radar, and Colorado State University's (CSU) S-band polarimetric radar, CHILL. The data set and analysis is further augmented with data from CSU's LMA (Lightning Mapping Array).