Principal Component Analysis of Equatorial Geomagnetic and Ionospheric Diurnal Variations

Abstract

Mean diurnal variations of the H and D components of the geornagnetic field and the Total Electron content (TEC) at selected stations, close to the dip equator, at low latitude away from the equatorial electrojet influence and close to thé Iatitude ofthe Sq focus are exalnined through the rnethod of Principal Component Analysis for strong electrojet, weak electrojet and courrter electrojet days. It is shown ihat the strength ofthe electrojet influences H and D variations at even higher latitudes largely through the second principal cornponent. For D, in particular, the first colìlponent is shown to be largely unaffected by the changes in the electrojet strength.