A study of the pre-sunrise F-layer stratification at Kodaikanal

Abstract

The pre-sunrise phenomenon of a rapid drop in the maximum ionic density of F-layer followed by an increase in the semi-thickness and height of the layer and stratification is described. The phenomenon, which is found to occur prominently during periods of low or moderate solar activity and during winter months, is discussed in relation to the distortion of the overhead Sq. current system and vertical drift of ionization.