资源环境科技发展态势分析平台

Two severe hailstorms that occurred during spring in east China were simulated by the Weather Research and Forecasting model, version 3.9, with four bulk microphysics schemes. Despite some general similarities in the simulation results, the microphysical schemes produced many differences in the radar structure, surface precipitation, wind field, and the mass of hydrometeors. In particular, the Morrison (MOR) scheme produced the best prediction of the radar structure, while the Milbrandt-Yau two-moment (MY2) scheme produced the worst. The mass of ice-phase particles differed greatly in different schemes. An accumulation zone of supercooled rainwater was found in the WDM6 scheme. Analysis of the mass and heat budgets of hydrometeors revealed that embryos of hail were mainly formed through the collection of ice and rain (MOR) or conversion from graupel (MY2), and developed by collecting cloud droplets (MOR) or rainwater (MY2). Microphysical processes generally cooled the air at lower levels while warming it in the mid-upper troposphere. Based on the 1-km resolution results simulated by MOR and MY2, the growth mechanism of hailstones was analyzed preliminarily. Hail embryos were first formed at the upper edge of the upright main updraft, which could be regarded as the "embryo curtain", and developed through up-down cycling. To conclude, we present a conceptual model of the initial, developing, mature and dissipating stages of the two hailstorm cases.