Day‐to‐day variability of foEs in the equatorial ionosphere. Issue 5 (13th September 2013)

• Record Type: Journal Article
• Authors: Somoye, E. O.; Akala, A. O.; Adeniji‐Adele, R. A.; Onori, E. O.; Ogwala, A.; Karimu, A. O.
• Is Part Of: Radio science. Volume 48:Issue 5(2013:Oct.)
• Page Start: 513
• Page End: 518
• Publication Date: 2013-09-13
• Subjects: Radio meteorology -- Periodicals; Radio wave propagation -- Periodicals; 621.38405
• DOI: 10.1002/rds.20057
• Languages: English
• ISSNs: 0048-6604

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>[1] Diurnal, seasonal, and solar cycle effects of the variability (VR) of the critical frequency of sporadic <italic>E</italic> layer (<italic>f<sub>o</sub>E<sub>sq</sub></italic>) are investigated at Ibadan (7.4°N, 3.9°E, 6°S dip) in the African sector during high solar activity (HSA) year of 1958 (<italic>Rz</italic> = 181), moderate solar activity (MSA) year of 1973 (<italic>Rz</italic> = 30), and low solar activity (LSA) year of 1965 (<italic>Rz</italic> = 17). The diurnal variation of <italic>f<sub>o</sub>E<sub>sq</sub></italic> VR is characterized by post‐midnight (32%–78%) and pre‐midnight (20%–84%) peaks during high solar activity (HSA), the only epoch of the three showing these peaks and a diurnal trend. While the daytime <italic>f<sub>o</sub>E<sub>sq</sub></italic> VRs of the three epochs show no seasonal trend, pre‐midnight and post‐midnight, the <italic>f<sub>o</sub>E<sub>sq</sub></italic> VRs during HSA and LSA show seasonal trends. Similarity is observed in the curve of reciprocal of percentage occurrence of <italic>E<sub>sq</sub></italic> and that of <italic>f<sub>o</sub>E<sub>sq</sub></italic> VR, indicating inverse variation of percentage occurrence and <italic>f<sub>o</sub>E<sub>sq</sub></italic> VR. Longitudinal influence is observed in the diurnal variation of HSA and MSA July <italic>f<sub>o</sub>E<sub>sq</sub></italic> VR of Ibadan (7.4°N, 3.9°E, 6°S dip) in the African sector, which is in the neighborhood of the Greenwich Meridian (GM); Singapore (1.3°N, 108.3°E, 17.6°S dip) in the Asian sector, east of GM; and Huancayo (12°S, 284.7°E, 1.9<sup>0</sup> dip) in the American sector, west of GM.</p> </abstract>