## 3 Results and Analyses
The PPEF represents the transmission of the electric fields from high to low latitudes as a result of the action of the solar wind magnetosphere dynamo. Figure 3: The EEJ variations for (**a,b**) America, (**c,d**) Africa, and (**e,f**) Asia. The median is shown as background EEJ. The disturbance of EEJ (dEEJ) is included for each case in blue color (**b,d,f**). The SSCs and HSSW are highlighted with vertical yellow and green lines, respectively. Figure 5 shows the median average of the TEC estimated by the IRI-2012 model and that from the IGS GNSS GIMs during February 2014. For both cases, there is a clear alignment of the TEC to the magnetic field, and the two characteristic enhanced EIA crests are located at about \(\pm 15^{\circ}\) magnetic latitudes. The IRI-2012 model lacks an accurate representation of the actual median TEC during this month. The IGS GIM shows an enhanced TEC in the southern hemisphere (Figure 5b), whereas the IRI-2012 model shows lower values, providing similar TEC values for both northern and southern high latitudes (Figure 5a). Concerning the distribution of the TEC along the EIA crests, the IRI-2012 underestimates the TEC in the northern EIA crest in the African and Asian sectors and at both EIA crests in the American sector. In general, the IRI-2012 model shows narrower crests, whereas the IGS crests are wider and have a more abrupt distribution of values than that of the IRI-2012, which shows a smooth shape. Figures 6 and 7 show the koograms (time-longitudinal dependence along red lines shown in Figure 5) of the TEC near the EIA crests. Here, we remove the quiet-time TEC by setting Am = 6 in the PCA-based model of [62]. For all three datasets (IGS, IRI-2012 and PCA-based model), the profiles shown in Figure 5 (the southern and northern EIA crests and the magnetic equator) were first extracted, and the TEC differences to quiet-conditions (Am = 6) TEC from 10 to 28 February 2014 were computed. Finally, the median values of the full koogram were averaged to detect the correlations with space weather and geomagnetic indices. The averaged TEC koograms are shown in the bottom panels of Figures 6 and 7, whereas the SSCs and the HSSW are shown with vertical yellow and green lines, respectively. The differences between the koograms from IGS GIMs and the PCA-based model are shown in Figure 7. In this figure, clear responses to the different storms are seen after the SSCs and HSSW events. The PCA-based model shows a good estimation of the quiet-time TEC for this case study, showing values centered to zero TECU, i.e., TEC disturbances between 11 and 16 and 25 and 27 February are nearly zero TECU. From the residuals, there is an observation of an enhanced TEC during the storms in the Asian and American sectors  
Figure 4: The PPEF variations for **(a,b)** America, **(c,d)** Africa, and **(e,f)** Asia. The median is shown as background PPEF. The disturbance of PPEF (dPPEF) is included for each case in blue color. The SSCs and HSSW are highlighted with vertical yellow and green lines, respectively. (approximately at 90\({}^{\circ}\) W and 90\({}^{\circ}\) E) with respect to the African sector (0\({}^{\circ}\) E). The enhanced TEC appeared with the HSSW on 19 February; the TEC enhancements were over 20 TECU, and a mean value (the bottom panel) exceeded 15 TECU. The differences between the keograms of the IRI-2012 model and the IGS GIMs show smooth responses of the TEC, which covers all the storms (Figure 7). No clear distinction between the events is seen, and the African sector (0\({}^{\circ}\) E) seems to have an enhanced TEC with respect to the Asian and American sectors, a feature that is not accurate regarding the residuals of the IGS TEC GIMs we observe in Figure 6. In this figure, there are observations of a clear bias, approximately overestimating the actual TEC by 20 TECU.