[01] Ayokunnu Olalekan David, Physics Department, The Polytechnic, Ibadan, Nigeria. [02] Jacob Olusegun Adeniyi, Physics Department, Landmark University, Omu-Aran, Nigeria. [03] Dare Oluseye David, Physics Department, Dominion University Ibadan, Ibadan, Nigeria. [04] Animasaun Ismail Adekunle, Department of Science Laboratory Technology, The Polytechnic, Ibadan, Nigeria.

The study is on F2 layer peak at fixed height of the ionosphere. The height was examined from 100 km up to its peak for seasonal, diurnal, solar cycle and latitudinal variations. Variations from the African and Southern American sectors of the equatorial region were analyzed using data from three equatorial stations namely: Ilorin, Nigeria (8.5°N, 4.5°E, -2.96 dip), Fortaleza, Brazil (3°S, 38°W, -7.03dip), and Jicamarca, Peru (12°S, 76.8°W, 0.74dip). Also, previous results from this region were confirmed in the study. It was observed that the departure from the day time electron density from that of a simple Chapman variation begins from the altitude of 180 km during the equinox months and about 210 km at the solstice months at the stations of observation. The maximum day time peak varies from 300-319 km and that of the post-noon is about 312-417 km. The h_mF2 at Fortaleza was observed to show no prominent pre-noon peak, during the September equinox. A midday bite-out occurs between 1200-1500 hour local time, it was observed that the electron density peaks between 2-4 hours after which the height reaches its peak in all the stations except at Fortaleza where a distinct midday bite-out was not observed during the June and December solstices and September equinox, showing the seasonal, diurnal and latitudinal variations. The features observed find their explanation in the dynamics of the equatorial ionosphere of the stratospheric-ionospheric couplings.

Stratospheric-ionospheric Coupling, Equatorial Ionosphere, Low Solar Activity

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