Issue: 3 , Volume: 47 , Уear of publication: 1995

There is improved the model for the description of the longitude-temporal variations of the F2-layer critical frequency which is based on the notion about the universal variation. This variation is characterized by the united change of foF2 at the Universal Time (UT) at all longitudes of the given latitude ring. In this paper the temporal and longitudinal dependence of the universal component amplitude is investigated. It was done by the selection of the best approximation of the observed foF2-variations by means of the model in the form of the sum of the local and universal components.