Concerning a lunar modulation of geomagnetic activity

Abstract

The behavior of the daily KP index of magnetic activity is investigated as a function of lunar phase by the method of superposed epochs. The analysis indicates a slight but statistically significant enhancement of geomagnetic disturbance during several days following full moon and, with marginal significance, a slight diminution of disturbance during several days preceding full moon. A small dip in KP, found at the phase of new moon, is shown to be without statistical significance.