Abstract:
Results are presented from a study on the occurrence of M and N traces on ionograms at the equatorial station Kodaikanal, with particular reference to their associations with various sporadic configurations. It is shown that M and N echoes occur on ionograms close to the magnetic dip equator in association with sporadic E layer configurations that are characteristics of the equatorial zone. Their occurrence is characterized by the presence of either an M echo or a combination of M and N echoes and rarely as an N echo. The M and N echoes together occur mostly with blanketing type sporadic E layers and is basically a post-noon event. The M echo occurs with equatorial sporadic E and is a pre-noon event with a characteristic seasonal variation.
