Global atmospheric electrical circuit Global atmospheric electrical circuit The global atmospheric electrical circuit is the course of continuous movement of atmospheric electricity between the ionosphere and the Earth. Through solar radiation, thunderstorms, and the fair-weather condition, the atmosphere is subject to a continual and substantial electrical current. Principally, thunderstorms throughout the world carry "negative" charges to the earth, which is then discharged gradually through the air in fair weather. This atmospheric circuit is central to the study of atmospheric physics and meteorology. It is used in the prediction of thunderstorms, and was central to the understanding of electricity. In the past it has been
Radio propagation propagation. The interference between the direct beam line-of-sight and the ground reflected beam often leads to an effective inverse-fourth-power (1/distance) law for ground-plane limited radiation. Lower frequency (between 30 and 3,000 kHz) vertically polarized radio waves can travel as surface waves following the contour of the Earth; this is called "groundwave" propagation. In this mode the radio wave propagates by interacting with the conductive surface of the Earth. The wave "clings" to the surface and thus follows the curvature of the Earth, so groundwaves can travel over mountains and beyond the horizon. Ground waves propagate in vertical polarization so vertical