Day-to-Day Variability of the Sq Geomagnetic Field Variation

Abstract

Much apparent day-to-day variability in the H component of the Sq variation in low and middle latitudes is not due to a variability in ionospheric currents, but arises from contamination by often unrecognized disturbance field variations associated with distant agnetospheric currents. There appears to be little, if any, day-to-day variability in the shape, type or phase of the pure Sqvariation. There is, however, a substantial day-to-day variability in the daily range of Sq and this has a worldwide rather than a local cause. No conclusive evidence exists for motion of the Sq foci. In low and middle latitudes the Sq variation is essentially a daytime phenomenon.