Abstract
The electrical charge on an ice-coated probe during riming and glazing in natural cloud droplets was observed at the top of a mountain. The observations were carried out under a condition of sufficient shielding from the external field.
The conclusions obtained were as follows :
1. When micro snow particles were contained in air, the probe was generally charged positively, but when snow particles in the air were relatively large and round, the probe was electrified negatively.
2. The necessary condition for the electrification of the probe was not the existence of cloud droplets in the air, but the collision of snow particles in the air with the probe.
3. The difference between the temperatures on the surfaces of snow particles and on the surface of the probe had some effect on the electrification of the probe, but the sign of it was opposite to that found by Reynolds, Brook and Gourley.
From the results, it is considered that micro mechanism of the collision of the snow particles with the probe is significant for the electrification of the probe, for examples, the tearing off of fine structure of the snow particles, and the existence of liquid film on the surface of the probe.
