Equatorial M(3000)F2 estimation of F2-layer models peak heights during high solar activity

Abstract

The validation of M(3000)F2 estimation of hmF2 based on four different formulatedmodels viz: (1). Shimazaki1, (2). Bradley and Dudeney2, (3).Dudeney3 and (4). Bilitza etal.4 at an Equatorial station in West Africa during high solaractivity period (1991) are carried to ensure its conformity with observed and InternationalReference Ionosphere (IRI) model. Fifteen (15) days local time data during the solsticesmonths (January and July) and equinoxes months (April and October) are selectedand analyzed. The results obtained show that the M(3000)F2 estimation of hmF2from the ionosonde-measured values using the Ionospheric Prediction Service(IPS-42) sounder compared to the observed values which were deduced using an algorithm from scaled virtual heightsof quiet day ionograms are highly correlated with Bilitza model. International ReferenceIonosphere (IRI-2012) model5 for the Equatorial region also agreeswith the formulation developed by Bilitza etal4 for the four different seasons of the year. hmF2 is highest (548 km) insummer (June solstice) season and lowest (471 km) in autumn (April equinox)season with daytimes peaks occurring at 1300LT during the solstices and at 1000 LTduring the equinoxes respectively. Also, the post-sunset peaks are highest (596km) at the winter season (Decembersolstice) and lowest (556 km) at the autumn season (October equinox)both occurring between 1800 – 2100 LT.