Optical polarization induced by electric fields of thunderstorms

Optical polarization measurements were made on isolated mountain thunderstorms by the use of a device built to map simultaneously the incident, vertical, and horizontal intensities of the scattered sunlight reflected from the thunderstorm. Results showed that the electric field contained within the thunderstorm prior to and after a lightning discharge is imaged by the local degree of polarization produced by the sunlight reflected from oriented ice crystals on the surface of the storm. The polarization was pronounced enough in simple isolated storms so that one could predict with reasonable certainty the locations of either cloud-to-ground or cloud-to-cloud strokes.