A study of blanketing sporadic E in the Indian equatorial region

Abstract

The paper describes the nature of the sporadic E layer of blanketing type observed at Kodaikanal (Lat. 10°.2 N; Long. 77°.5 E; dip: 3°.5 N). It is shown that in the Indian equatorial region, the frequency of occurrence of this type of E_s is abnormally large when compared to similar latitudes in the west and that changes of large magnitudes occur in the F2 layer of the ionosphere as well as in the horizontal force of the earth's magnetic field simultaneously with the appearance of the blanketing E_s. Lunar effects have also been shown to exist both in the time of appearance of blanketing E_s and in its strength. Some evidence exists to show that blanketing E_s as well as the blanketing frequency, f_b E_s, have a biennial maximum. These characteristics are discussed as part of the Far East Anomaly.