Analysis of Environmental and Physical Conditions of Hail Weather in the Region of Five-Hundred-Meter Aperture Spherical Radio Telescope

Luo Xiong; Luo Xiping; Zhao Jie; Zhang Xiaojuan; Li Lili

doi:10.16765/j.cnki.1673-7148.2026.02.004

Abstract：Based on hailfall information from 2006 to 2023 in the Five-hundred-meter Aperture Spherical Radio Telescope region(hereinafter referred to as the FAST region),combined with meteoro-logical observation data from soundings,radar,and satellite,twenty environmental physical parameters(characterizing water vapor conditions,thermodynamic and dynamic features,atmospheric instability,and characteristic height layers),as well as radar feature parameters and satellite TBB were used to ana-lyze the patterns of hail weather processes,key environmental physical parameters and their monitoring and warning thresholds in the FAST region.The results show that:(1)Hail in the FAST region primarily occurs in spring,mostly during the evening to nighttime hours.The duration of hail is 1-3 minutes,and the diameter of hail is less than 10 mm.The main path of hail clouds affecting the FAST region is from the northwest,with their primary source located in the southeast of Anshun City.(2)Among the selected similar physical parameters,T850-Td850,ΔT850-500,SWEAT,and SHR6 exhibit the smallest dispersion and can serve as key discriminative physical parameters for hail weather in the FAST region,providing important reference for potential forecasting operations.Specifically,the maximum threshold for T850-Td850 should not exceed 1.25℃(75th percentile),the minimum threshold for ΔT850-500,SWEAT,and SHR6 should not be lower than 22.63℃(25th percentile),170.03(25th percentile),and 22.88 m/s(25th percentile),respectively.Concurrently,WBZ and H-20℃need to fall within their 25th and 75th percentile ranges,specifically 3.55-3.86 km and 6.69-7.48 km.(3)For hail warning operations in the FAST region,radar physical parameters Zmax,VILmax,ET,H45 dBZ,H55 dBZ,and the ice-water ratio take the 25th percentile as their minimum thresholds,which are 60 dBZ,31.25 kg/m2,13.25 km,8.75 km,7.00 km,and 2.12,respectively.For satellite TBB,the 75th percentile(-44.9℃)is taken as the maximum threshold.