资源环境科技发展态势分析平台

Mechanisms of formation of differential reflectivity columns are investigated in simulations of a midlatitude summertime hailstorm with hailstones up to several centimeters in diameter. Simulations are performed using a new version of the Hebrew University Cloud Model (HUCM) with spectral bin microphysics. A polarimetric radar forward operator is used to calculate radar reflectivity and differential reflectivity Z(DR). It is shown that Z(DR) columns are associated with raindrops and with hail particles growing in a wet growth regime within convective updrafts. The height and volume of Z(DR) columns increases with an increase in aerosol concentration. Small hail forming under clean conditions grows in updrafts largely in a dry growth regime corresponding to low Z(DR). Characteristics of Z(DR) columns are highly correlated with vertical velocity, hail size, and aerosol concentration.