Challenges of the Polarimetric Update on Operational Radars in China—Ground Clutter Contamination of Weather Radar Observations

China New Generation Doppler Weather Radar (CINRAD) plans to upgrade its hardware and software achieve polarimetric function. However, the small-magnitude measurements were negatively affected by scattering characteristics of ground clutter filter’s response clutter. This contamination was characterized decreased differential reflectivity (ZDR) cross-correlation coefficient (ρhv), as well an increased standard deviation phase (ΦDP), generating a large-area long-term observational anomaly for eight radars in South China. Considering that outliers simultaneously appeared radar mainlobe sidelobe, variations before after mitigation (ΔZH) ρhv used quantitatively describing random dispersion caused sidelobe clutters. The performance algorithms also reduced contamination. deteriorated membership functions hydrometeor classification algorithm changed proportion classified echoes. empirical relations R(ZH, ZDR) R(KDP) broken quantitative precipitation estimation extra error considerably exceeded uncertainty drop-size distribution (DSD) variability R(ZH). above results highlighted negative impact on applications need be further investigated.