Latitudinal effect on the diurnal variation of the F2 layer at low solar activity

• The latitudinal effect on the diurnal variation of the F2 layer peak parameters at low solar activity was investigated.
• The tendency for the occurrence of the noon bite-out during the day decreases with increase in latitude, it is barely seen beyond 21.770°N magnetic latitude.
• The diurnal variation of the NmF2 peaks observed from the stations around the Equator does not conform to the typical Chapman layer variation.
• The time of formation and position of the EA crests is observed to be asymmetric.

The latitudinal effect on the diurnal variation of the F2 layer peak parameters at low solar activity was investigated. Our results reveal that the likelihood of the occurrence of a noon-bite out is reduced with increase in latitude. Beyond 21.770°N geomagnetic latitude, it is hardly noticed. Daytime maximum NmF2 peak occurs mostly after midday in the northern hemisphere. Similar variations occur in the southern hemisphere, although it varies with the seasons, and latitudes. The maximum ionization decreases with increase in latitude and NmF2 values during the equinoxes are higher than those of the solstice seasons, in the northern hemisphere. It is entirely different in the southern hemisphere. The rate of decay is faster during the solstice than during the equinoxes. Maximum hmF2 values occur at the equatorial ionosphere; the least is in the mid-latitude region. The time of formation and position of the EIA crests is observed to be asymmetric. It appears to be more consistent in the northern hemisphere than the south. These types of seasonal variations have been attributed to the daytime meridional wind, equatorial fountain effect and the location of the subsolar point in relation to the magnetic equator.