SIMULTANEOUS MEASUREMENTS OF THE CHARGE, SIZE, AND SHAPE OF HYDROMETEORS IN AN ELECTRIFIED CLOUD

With the use of an induction cylinder in conjunction with an optical array probe, simultaneous measurements were obtained of the size, shape, and charge of hydrometeors in a New Mexico thunderstorm. The particles with detectable charges (greater than 1-3 pC) were primarily graupel particles, and their charges are generally consistent with laboratory measurements of ice-ice collisional charging. The fraction with detectable charge increases with size, as does the magnitude of the mean charge. Also, the positively charged particles occur primarily at higher temperatures (> -22-degrees-C), and the degree of negative charging increases with decreasing temperature (down to -35-degrees-C).