Modeling and analysis of GPS-TEC low latitude climatology during the 24th solar cycle using empirical orthogonal functions

Storm Time Total Electron Content Modeling Over African Low‐Latitude and Midlatitude Regions

“…It was thus concluded, in a statistical sense, that F 10.7 p is a better representation of solar activity than F 10.7 index. It is worth to point out that there exist other previous works that emphasized the same idea (e.g., Bergeot et al, ; Liu & Chen, ; Zolesi & Cander, ), and thus, F 10.7 p is rather being used as solar activity representation in ionospheric modeling than the normal F 10.7 (e.g., Dabbakuti & Ratnam, , ; Ercha et al, , ; Tshisaphungo et al, ; Uwamahoro & Habarulema, ).…”

“…Thus, considering that original data sets are composed of a large number of storms, taking also into account that corotating interaction regions and coronal mass ejections‐driven storms are both included in the data sets, the three geomagnetic indices were all used to globally represent, at a latitudinal scale, different geomagnetic activity contributors to TEC changes due to storms. There also exists a couple of works that included all three geomagnetic indices in modeling over different latitude sectors (Dabbakuti & Ratnam, , ; Ercha et al, ; Tshisaphungo et al, ). On the other hand, while studying the ionospheric dependence on solar activity, Richards et al () noticed a least dependence of the F 2 peak electron density ( N m F 2 = T E C / τ , where τ is the ionospheric slab thickness; Davies, ; Leitinger et al, ; Stankov & Warnant, ) on the daily solar flux index at a wavelength of 10.7 cm ( F 10.7 ).…”

“…Different TEC models have long been developed and applied for ionospheric studies during both geomagnetically quiet and disturbed conditions (e.g., Chen et al, ; Dabbakuti & Ratnam, , ; Ercha et al, , ; Feng et al, ; Habarulema et al, , , ; Hajra et al, ; Kakinami et al, ; Li et al, ; Mao et al, , ; Mukhtarov et al, ; Uwamahoro & Habarulema, ; Watthanasangmechai et al, ). Findings about the performance of climatological models such as the International Reference Ionosphere (IRI) have shown that, on average, TEC is predicted quite well during geomagnetically quiet conditions although for some cases, IRI model underestimates or overestimates TEC magnitude (e.g., Adewale et al, ; Akala et al, ; Kenpankho et al, ; Rathore et al, ).…”

“…Empirical orthogonal functions (EOF) analysis has widely been used to model TEC during geomagnetically quiet periods, and findings revealed that its accuracy is high. Comparative studies have shown that EOF model predicts TEC more accurately than IRI model (Chen et al, ; Dabbakuti & Ratnam, , ; Ercha et al, ; Mao et al, , ). Recently, EOF analysis was used for the first time to model TEC during geomagnetic storms, and it was found that modeling results agree with observed TEC quite well for storms with nonsignificant ionospheric response while positive and negative storm responses were not sufficiently captured (Uwamahoro & Habarulema, ).…”

Global total electron content prediction performance assessment of the IRI-2016 model based on empirical orthogonal function decomposition

“…Many attempts have been made to specify ionospheric parameters using empirical approaches, because an empirical model can describe the general condition of the ionosphere without actual measured data (Feltens et al, 2011). Several ionosphere empirical models, such as Klobuchar, NeQuick, the Standard Plasmasphere Ionosphere Model (SPIM), and International Reference Ionosphere (IRI; Bilitza, 2001), are currently available.…”