Abstract
To investigate the mirror image relation between the electric potential gradient and charges on precipitation particles above the ground surface, a simultaneous observation system of the vertical structure of the electric potential gradient in the lower atmospheric layer and the charge on precipitation particles falling through the layer during a snowfall was developed. This system consists of a tethered balloon, observation stages on the tether and a microcomputer on the ground. Each stage has a field mill and a charge collector and it is possible to measure simultaneously the vertical component of the atmospheric electrical potential gradient and the maximum charge on precipitation particles of at most 4 stages at 5-second intervals at every 50 or 100m in altitude. Data are converted to digital signals at the stage, transmitted by digital optical communications with optical plastic fiber cables and stored in microcomputer on the ground.
Several measurements were carried out in March 1985 and some results were obtained. The mirror image relation was observed on the ground but it was not so clear aloft. It was considered that the charges on the precipitation particles were reelectrified during their falling near the ground surface.
