X-band polarimetric observations of cross coupling in the ice phase of convective storms in Taiwan

In this paper, experimental X-band polarimetric radar data fromsimultaneous transmission of horizontal (H) and vertical (V) polarizations (SHV) are shown, modeled, and microphysically interpreted. Both range-height indicator data and vertical-pointing X-band data from the Taiwan Experimental Atmospheric Mobile-Radar (TEAM-R) are presented. Some of the given X-band data are biased, which is very likely caused by cross coupling of theHandVtransmittedwaves as a result of aligned, canted ice crystals.Modeled SHVdata are used to explain the observed polarimetric signatures. Coincident data from the National Center for Atmospheric Research S-band polarimetric radar (S-Pol) are presented to augment and support the X-band polarimetric observations and interpretations. The polarimetric S-Pol data are obtained via fast-alternating transmission of horizontal and vertical polarizations (FHV), and thus the S-band data are not contaminated by the cross coupling (except the linear depolarization ratio LDR) observed in the X-band data. The radar data reveal that there are regions in the ice phase where electric fields are apparently aligning ice crystals near vertically and thus causing negative specific differential phase K_dp. The vertical-pointing data also indicate the presence of preferentially aligned ice crystals that cause differential reflectivity _dr and differential phase f_dp to be strong functions of azimuth angle.