Quantitative Error Analysis of Next-Generation Polarimetric Phased Array Radar Measurements: Cylindrical versus Planar Configurations

The community’s understanding of polarimetric phased array radar (PPAR) for meteorological applications has advanced significantly over the past 15 years. Initial weather measurements from cylindrical (CPPAR) and planar (PPPAR) configurations, installed at the University of Oklahoma, were used to analyze the advantages and disadvantages of these systems in producing high-quality polarimetric weather data. This comparison focused on the error statistics of polarimetric measurements during convective rain events. Specifically, the standard deviations and mean biases of measurements from the Horus and CPPAR systems were calculated and compared with those from an operational WSR-88D radar. The results indicate that PPPAR faces significant challenges in producing high-quality polarimetric data, especially at large steering angles. There are inherent problems with polarimetric purity and mismatches in dual-polarimetric beams when steering away from the broadside or principal planes. Furthermore, stripes were observed in the Horus RHI scans when the beam steers off broadside and ring-like signatures were observed in the PPI scans, possibly due to sidelobe contamination. These findings underscore the importance of understanding scanning loss issues and system performance degradation for 2D PPPAR, requiring very complicated/trouble-some beam-to-beam calibrations. Given these challenges, particularly the degradation of PPPAR performance when the beam is away from the broadside, the cylindrical configuration emerges as a promising alternative. It offers the potential to enhance current operational radars by providing high-quality polarimetric data and rapid data updates. Finally, the potential of dish-based operational radars, 1D PPPAR, 2D PPPAR, and CPPAR are evaluated and compared.