Charge distribution in thunderstorm clouds

The negative charge involved in lightning flashes to ground is found to be distributed in a manner strongly dependent upon the direction of movement of the storm, and does not, in general, constitute a nearly vertical column as proposed by Malan and Schonland. Based on a study of electric field-changes measured at two stations 10 km apart involving 539 return strokes from 84 flashes in 10 storms, we conclude that the horizontal component of the in-cloud channel on the average exceeds the vertical component, and points in the direction of storm motion. An analysis is given of the five methods of Malan and Schonland, on the basis of which we suggest that significant horizontal components are also compatible with their observations of a vertical column, and that the ‘nearly vertical’ aspect of the charge distribution has been over-emphasized.