Weather radar is an active remote sensing device used to monitor the full lifecycle changes in severe convective weather with high spatial and temporal resolution. Effective radar calibration is a crucial foundation for ensuring the high-quality application of observational data. This paper utilizes a UAV platform equipped with a high-precision RTK system and standard metal spheres to study the principles and methods of metal sphere calibration, constructing a complete calibration process and calibration accuracy evaluation metrics. Additionally, a collocated radar comparison observation experiment was conducted for cross-validation, and metal sphere calibration tests were performed on problematic radars. The experimental results indicate the following: (1) The combined application of a high-precision RTK system and a laser range camera can provide real-time position information on the metal sphere, improving the efficiency of radar target acquisition. (2) The calibration method based on UAV-suspended metal spheres can periodically conduct the quantitative calibration of Z and Z_DR, achieving calibration accuracies within 0.5 dB and 0.2 dB, respectively, and supports the qualitative inspection of key parameters such as beamwidth and pulse width. (3) During field tests, a high success rate “coarse adjustment + fine adjustment + staring” sphere-finding technique was established, based on automatic switching between RHI, PPI, and FIX scanning modes. This method directs the UAV to adjust the metal sphere to the center of the radar distance bin, reducing the impact of uneven beam filling and bin crossing, ensuring the accuracy of scattering characteristic measurements.

Utilizing spaceborne precipitation radar (SR) to evaluate ground-based weather radar (GR) reflectivity consistency is essential for early detection of performance issues. However, existing SR vs. GR matching methods often overlook some error sources, such as insufficient beam coverage and non-uniform precipitation. This study introduces enhanced methods for SR vs. GR matching, including beam blocking identification, precipitation uniformity assessment, and improved time matching. Validation was performed using the FY-3G satellite’s precipitation measurement radar (PMR) and four S-band radars in Hunan Province, China. Our analysis demonstrates that integrating clear-sky ground clutter, long-duration precipitation echoes, and terrain data effectively detects actual beam blocking in GR. Selecting data with a time difference of 180 seconds or less, within 230 kilometers of the GR center, GR reflectivity between 20 dBZ and 35 dBZ, and a signal-to-noise ratio (SNR) above 15 dB significantly mitigates random errors in SR vs. GR matching results. Additionally, we explore a method for tracking reflectivity deviations within a “ground-satellite-ground” radar network, validated through adjacent GR comparisons. This approach, based on the Changsha Meteorological Radar Calibration Center’s reference radar. The method was validated using adjacent ground radar comparison, showing a correlation between the two methods with a minimum deviation transfer difference of 0.29 dB and a maximum of 1.13 dB. Additionally, the Yiyang radar exhibited slightly higher reflectivity, indicating that the method is both reliable and practically applicable.

The detection accuracy of weather radar directly affects the precision of meteorological monitoring and early warning, so it is important to establish a mature calibration framework. Active Radar Calibrator (ARC) can generate simulated targets with predefined Doppler frequency and radar cross-section at designated distances, serve as a critical tool for end-to-end absolute calibration of weather radars. This study proposes an ARC-based absolute calibration method for weather radar reflectivity (Z) and develops a Weather radar active calibrator (WARC) tailored for meteorological applications. Firstly, a calibration model for Z was established based on electromagnetic scattering theory, considering factors such as WARC-radar distance, atmospheric attenuation path differences, and radome losses. Secondly, a traceable WARC-RCS calibration chain was constructed to align measurements with national metrological standards. Finally, cross-validation experiments on the accuracy ofWARC and passive suspended metal spheres were conducted at the Changsha Meteorological Radar Calibration Center, by using an S-band reference weather radar. Results demonstrate that the WARC system simultaneously generates four simulated targets with quantifiable parameters. The mean calibration error for Z was -0.325 dB, while velocity and spectral width mean errors were -0.041 m/s and 0.021 m/s, respectively. WARC performance align closely with that of traditional metal sphere calibration methods, confirming both the accuracy and practicality of the simulated targets it generates.

Lightning rods, while essential for protecting weather radars from direct lightning strikes, act as persistent non-meteorological scatterers that can interfere with signal transmission and reception and thereby degrade detection accuracy and product quality. Existing studies have mainly focused on X-band and C-band systems, and robust, measurement-based quantitative assessments for S-band dual-polarization radars remain scarce. In this study, a controllable tilting lightning rod, a high-precision Far-field Antenna Measurement System (FAMS), and an S-band dual-polarization weather radar (SAD radar) are jointly employed to systematically quantify lightning-rod impacts on antenna electromagnetic parameters under different rod elevation angles and azimuth configurations. Typical precipitation events were analyzed to evaluate the influence of the lightning rods on dual-polarization parameters. The results show that the lightning rod substantially elevates sidelobe levels, with a maximum enhancement of 4.55 dB, while producing only limited changes in the antenna main-beam azimuth and beamwidth. Differential reflectivity ($Z_{DR}$) is the most sensitive polarimetric parameter, exhibiting a persistent positive bias of about 0.24–0.25 dB in snowfall and mixed-phase precipitation, while no persistent azimuthal anomaly is evident during freezing rain; the co-polar correlation coefficient (${\rho }_{hv}$) is only marginally affected. Collectively, these results provide quantitative, far-field evidence of lightning-rod interference in S-band dual-polarization radars and provide practical guidance for more reasonable lightning-rod placement and configuration, as well as useful references for $Z_{DR}$-oriented polarimetric quality-control and correction strategies.