The Occurrence of Sporadic-E Layer over Equatorial Anomaly Crest Region Bhopal

Abstract

Ionospheric anomaly crest regions are most challenging for scientific community to understand its mechanism and investigation, for this purpose we are investigating some inospheric result for this region. The study is based on the ionogram data recorded by IPS-71 Digital Ionosonde installed over anomaly crust region Bhopal (Geo. Lat. 23.2° N, Geo. Long 77.4° E, Dip latitude 18.4°) over a one year period from January 2010 to December 2010. The studies were examined in four different variations such as: Hourly variation, diurnal variation, seasonal variation and hourly-seasonal variation. The occurrence probability of this layer is highest in summer solstice, moderate during equinox and low during winter solstice. Remarkable occurrence peaks appear from June to July in summer and from December to January in winter. The layer occurrence showed a double peak variation with distinct layer groups, in the morning between 0000–0400 UT and the other during evening between 1100–1600 UT. The morning layer descent was associated with layer density increase indicating the strengthening of the layer while it decreased during the evening layer descent. The result indicates the presence of semi-diurnal tide over the location while the higher descent velocities could be due to the modulation of the ionization by gravity waves along with the tides. The irregularities associated with the gradient-drift instability disappear during the counter electrojet and the current flow is reversed in westward.