The local diurnal variation of cloud electrification and the global diurnal variation of negative charge on the Earth

Both the amplitude and the phase of the ionospheric potential and Carnegie curve of atmospheric electricity are considered to distinguish causes for the negatively charged earth in fair weather. Satellite‐observed longitudinal distributions of electrical activity are convolved with local diurnal variations of cloud‐to‐ground lightning and point discharge current to produce universal diurnal variations which are compared with the Carnegie curve. The amplitude ratio (maximum‐minimum)/mean) for the predicted universal diurnal variation of point discharge shows good agreement with the Carnegie curve, whereas the predicted amplitude ratio for lightning is 2–3 times greater. These comparisons suggest that conduction current other than lightning is the dominant charging agent for the Earth's surface.