Surface Measurements of the Electrical Properties of Warm Clouds over the Sea

Abstract

THE electrical properties associated with warm cloud precipitation have been measured routinely at Hilo, on the windward coast of the Island of Hawaii, for the past three years. Warm clouds in this locality typically form over the ocean east of the island and move inland with the north-east trade wind. The present series of measurements is part of a continuing investigation of the mechanism of charge separation in warm clouds and of how such processes may be related to thunderstorm electricity. It is important to study the electrical properties of non-freezing clouds, which consist only of liquid cloud droplets, to clarify the role of the liquid phase in the complex liquid-ice continuum of thunderstorms, and changes in electrical properties also are intimately associated with the dynamic behaviour of clouds. We believe that atmospheric electrical measurements will provide useful information on the growth and development of warm clouds.