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

Remote Sensing

Chian Zhang¹  Guangxin He²  Chong Wu³  Chao Chen³  Liping Liu³  Juan Li⁴ 

[1] Beijing Metstar Radar Co., Ltd., Beijing 100094, China;Key Laboratory of Meteorological Disaster, Ministry of Education (KLME)/Joint International Research Laboratory of Climate and Environment Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing 210044, China;Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China;School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044, China;

关键词: dual-polarization radar;    radar observations;    data quality control;   

DOI  :  10.3390/rs13020217

来源: DOAJ

【 摘 要 】

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

【 授权许可】

Unknown