Equatorial vertical plasma drifts and the measured and IRI model-predicted F 2-layer parameters above Ouagadougou during solar minimum

Abstract

In this paper, hourly median value of ionosonde measurements: peak height F 2 -layer (h m F 2 ), F 2 -layer critical frequency ( f o F 2 ) and propagation factor M(3000)F 2 made at near-equatorial dip latitude, Ouagadougou, Burkina Faso (12• N, 1.5 • W; dip: 1.5• N) and relevant F 2 -layer parameters: thickness parameter (B o ), electron temperature (T e ), ion temperature (T i ), total electron content (TEC) and electron density (N e ) (at the fixed altitude of 300 km) provided by the International Reference Ionosphere (IRI) model for the longitude of Ouagadougou are contrasted with the IRI vertical drift model to explore in detail the monthly climatological behavior of equatorial ionosphere and the effects of equatorial electrodynamics on the diurnal structure of F 2 -layer parameters. The analysis period covers four months representative of solstitial and equinoctial seasonal periods during solar minimum year of 1987 for geomagnetically quiet-day. It is demonstrated that the month-by-month morphological patterns between vertical E × B drifts and F 2 -layer parameters range from worst to reasonably good and are largely seasonally dependent. A cross-correlation analysis conducted between equatorial drift and F 2 -layer characteristics yield statistically significant correlations for equatorial vertical drift and IRI-B o , IRI-T e and IRI-TEC, whereas little or no acceptable correlation is obtained with observational evidence. Examination of the association between measured f o F 2 , h m F 2 and M(3000)F 2 illustrates consistent much more smaller correlation coefficients with no systematic linkage.

Impacts of solar activity on performance of the IRI-2012 model predictions from low to mid latitudes

“…This approach has the disadvantage of discrepancies between the experimental and model TEC values during high solar activity years (Mukherjee et al 2010). The IRI-2007 was released with many enhanced features and showed a good agreement with the observed data at the anomaly crest station (Chauhan and Singh 2010 IRI-2001, and IRI01-corr) at different equatorial and low-latitude regions (Watthanasangmechai et al 2012;Wichaipanich et al 2012;Kakinami et al 2012;Okoh et al 2012;Oyekola 2012;Oyekola andFagundes 2012a, 2012b).…”

Testing and validating IRI-2016 model over Ethiopian ionosphere

“…The seasonal VTEC value attained their peak values about 12:00 UT (15:00 LT) to 15:00 UT/18:00 LT hours and attained minimum val-ues in 0:00 UT-3:00 UT (3:00 LT-6:00 LT) and 21:00-0:00 UT (0:00-3:00 LT). The seasonal observed discrepancies between the GPS-VTEC and modeled VTEC values have been slightly occurred in the time interval between 9:00 and 15:00 UT (12:00-18:00 LT), which is similarly as noted by different findings (Rios et al 2007;Nigussie et al 2013;Oyekola 2012;Sethi et al 2011).…”

TEC prediction performance of the IRI-2012 model over Ethiopia during the rising phase of solar cycle 24 (2009–2011)

“…Sethi et al 2011;Oyekola 2012), the overestimation of daytime VTEC by the IRI-2012 model may be attributed to the model's overestimation of the equatorial vertical drift. Oyekola (2012), for instance, described a linkage between modeled TEC and vertical drift.…”