关键词: 冰雹, 地形, 冷池, 中尺度辐合线, 次级环流

Abstract:

Based on the fusion of NCEP 1°×1°upper air reanalysis data and automatic weather station data, high-density sounding field was established. The environmental convection parameters of this high-density space-time field were calculated and analyzed about a hailstorm convective weather on Jun 6th, 2016 in Tianjin and the development mechanism of the hailstorm was also studied combined with the retrieval data of the variational doppler radar analysis system (VDRAS). The results show that the hailstorm weather occurred under the background of Mongolia cold vortex. The local thermodynamic circulation which formed by uneven surface heating in mountain area, and the southeast airflow’s lifting, which formed by topographic forcing, they took effect together to generate convective storm in western mountain area of Beijing. During the convective cells moving eastward, the secondary circulation generated by cold pool and meso-scale energy front which formed in the surrounding high energy region, it were favorable for development and maintenance of the hailstorm. Meanwhile, the east airflow from Bohai made water vapor in the boundary layer accumulate and instability stratification develop. In addition, the indexes of CAPE, LI and TTm at high resolution considering the surface temperature and moisture could not only fill in the gap that there was no sounding stations in Tianjin, but also reflect precisely the meso-scale environmental differences in the genesis and development of hailstorm, consequently, they had obvious indicative significance for the hailstorm local characters. It was propitious to the occurance of hailstorm in the junction between surface convergence line and water vapor bands.

Key words: hailstorm terrain, cool poor, meso-scale convergence line, secondary circulation