Statistical analysis of terrain blockage impacts on the CINRAD network based on DEM data

The weather radar beam energy is usually attenuation due to the terrain blockage,which will lead to lower intensity of radar reflectivity and unrealistic radar quantitative precipitation estimation (QPE). Therefore, it is an important basic work to statistics and analyze of radar beam blockage. This paper simulates and analyzes the observational environments of the 212 operational CINRAD radars using Shuttle Radar Topography Mission (SRTM) digital elevation data. The shielding angle, the Beam Blockage Percentages (BBPs) at 0.5°, 1.5°, 2.4°, 3.4° and 4.3° elevation angles in VCP21 mode, the BBPs in hybrid scan mode and subarea hybrid scan mode, and the effective coverage of observational range are first calculated for each weather radar. The terrain blockage effect on the CINRAD radar network is then analyzed statistically and the BBP mosaic image of the CINRAD radar network is mapped. The 11 CINRAD radars base data in Guangdong province in August 2019 are used to verify the analysis result of single station and radar network beam blockage. The results indicate that the effective observational coverage of the CINRAD radar network region exceeds 70%. The analysis results of BBPs are highly consistent with the actual data, and have positive contributions to radar reflectivity correction, QPE correction and other products.