Wind tunnel studies on the melting of ice hydrometeors: the effect of collision and turbulence on melting (HydroCOMET)

点击翻译按钮获取中文摘要

Severe precipitation events are responsible for billions of Euros economic loss and cause hundreds of injuries and fatalities every year in Europe and worldwide. Hail, freezing rain, extreme rainfall and the associated floods and landslides from summer time thunderstorms and ice storms in winter are the most hazardous weather phenomena in our continent having harmful economic, societal and natural impacts. Therefore, the short term forecast of the form, intensity and dislocation of such convective cloud and precipitation systems is of crucial importance. The tools used for short term weather prediction, i.e. the numerical weather models and the radar based remote sensing precipitation facilities suffer from the poorly understood microphysics of the mixed phase cloud and precipitation particles. In particular, proper representation of the melting processes of snow, hail and graupel is required. The aim of the HydroCOMET project is to deliver a set of parameterizations describing the most important physical properties of melting ice hydrometeors, including their continuously varying shape, fall velocities, and their liquid water fraction during melting. Furthermore, the effects of turbulence in the air stream and the collision of melting hydrometeors with supercooled droplets will be investigated. The experiments will be carried out at the Mainz vertical wind tunnel which is a world-wide unique facility for investigating single cloud and precipitation particles under simulated atmospheric conditions. New parameterizations of the microphysical properties of melting ice hydrometeors provided by the HydroCOMET experiments will be implemented in precipitation models and radar retrieval algorithms.