Open AccessIonospheric Peak Electron Density and Performance Evaluation of IRI‐CCIR Near Magnetic Equator in Africa During Two Extreme Solar Activities
Author(s) -
Adebesin B. O.,
Rabiu A. B.,
Obrou O. K.,
Adeniyi J. O.
Publication year - 2018
Publication title -
space weather
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 56
ISSN - 1542-7390
DOI - 10.1002/2017sw001729
Subject(s) - solstice , equinox , daytime , solar minimum , atmospheric sciences , solar maximum , ionosphere , environmental science , equator , morning , tec , solar cycle , latitude , physics , geology , geodesy , geophysics , solar wind , astronomy , magnetic field , quantum mechanics
The F 2 layer peak electron density ( NmF 2) was investigated over Korhogo (Geomagnetic: 1.26°S, 67.38°E), a station near the magnetic equator in the African sector. Data for 1996 and 2000 were, respectively, categorized into low solar quiet and disturbed and high solar quiet and disturbed. NmF 2 prenoon peak was higher than the postnoon peak during high solar activity irrespective of magnetic activity condition, while the postnoon peak was higher for low solar activity. Higher NmF 2 peak amplitude characterizes disturbed magnetic activity than quiet magnetic condition for any solar activity. The maximum peaks appeared in equinox. June solstice noontime bite out lagged other seasons by 1–2 h. For any condition of solar and magnetic activities, the daytime NmF 2 percentage variability (% V R ) measured by the relative standard deviation maximizes/minimizes in June solstice/equinox. Daytime variability increases with increasing magnetic activity. The highest peak in the morning time NmF 2 variability occurs in equinox, while the highest evening/nighttime variability appeared in June solstice for all solar/magnetic conditions. The nighttime annual variability amplitude is higher during disturbed than quiet condition regardless of solar activity period. At daytime, variability is similar for all conditions of solar activities. NmF 2 at Korhogo is well represented on the International Reference Ionosphere‐International Radio Consultative Committee (IRI‐CCIR) option. The model/observation relationship performed best between local midnight and postmidnight period (00–08 LT). The noontime trough characteristics is not prominent in the IRI pattern during high solar activity but evident during low solar conditions when compared with Korhogo observations. The Nash‐Sutcliffe coefficients revealed better model performance during disturbed activities.