Electric charge carried by ice particles ejected from the surface of riming graupel

E. ÁVILA, R. PEREYRA, A. LIGHEZZOLO

Workshop; Workshop : Electrification of Water Drops and Ice Particles: Through Simulations, in the Laboratory and in the Natural Environment; 2009

The riming process in clouds consists on the capture and subsequent freezing of supercooled cloud droplets by falling snow crystals. This process occurs in mixed-phase regions of clouds where the temperature is below 0C. It is a very efficient mechanism of ice crystal growth which leads to the production of precipitation in the form of rainfall or snowfall. -we have measured electric charge carried by INDIVIDUAL particles ejected from the surface of an ice growing by riming under the condition of secondary ice crystal production. -we found that probably less than 1% of the ejected particles carry charge > 1 fC -The ejected fragments are negatively charged with around -15 fC -The mechanism of ejection of charged particles could, in principle, contribute to the positive charge acquired by individual precipitation particles of mm-size in the lower part of the cloud.