Variability of foF2 for an equatorial station and comparison with the foF2 maps in IRI model

• Published in: Journal of atmospheric and solar-terrestrial physics 2007-04, Vol.69 (6), p.721-733
• Main Authors: Adeniyi, J.O., Oladipo, O.A., Radicella, S.M.
• Format: Article
• Language: English
• Subjects: Earth, ocean, space; Equatorial ionosphere; Exact sciences and technology; External geophysics; F2 layer; IRI model; Physics of the high neutral atmosphere; Physics of the ionosphere; Physics of the magnetosphere; Variability
• ISSN: 1364-6826; 1879-1824
• DOI: 10.1016/j.jastp.2006.12.001

In this study, foF2 data obtained from an equatorial station in West Africa were subjected to an occurrence probability distribution test. This was done on an hourly basis, for all the 24 h of the day. The results show that the probability ( N p) of predicting foF2 within the range±of a standard deviation ( σ) centered on the mean ( μ) is ⩾0.68 is at least about 70% of the hourly set of data considered in this study irrespective of time of the day, season or solar cycle period. The distribution is not, however, perfectly symmetrically distributed around the mean. The seasonal hourly averages of foF2 were compared with those of IRI predictions. The IRI representation was found to be very good at low and moderate solar activity for both day and nighttime when the ITU-R coefficients are used. This is also true of the daytime at high solar activity. The night time prediction is only fairly good when the URSI coefficients are used for the prediction.