Lunar Variations in the Ionosphere

Abstract

The global pattern of the observed lunar variations of the height and electron density of the F2 region is briefly summarized, new analyses being presented for Canberra (f0F2), Brisbane (h'F2), and Washington (h' and f0F2). It is concluded that the height variation has an amplitude of from 1 to 3 km and a phase giving maximum height at 06 lunar hours at moderate latitudes and at 09 lunar hours at the geomagnetic equator. The critical frequency variation has an amplitude of from 2 to 4 per cent., maximum critical frequency occurring at about 09 lunar hours at moderate geomagnetic latitudes and 04 lunar hours at equatorial geomagnetic latitudes.