Panel (a) presents scatter plot of foF2 obtained from NeQuick model (red) and assimilation (black) as a function of coincident observed foF2 over the ionosonde stations considered in this study. Panel (b) presents scatter plot of TEC obtained from NeQuick model and assimilation as a function of coincident observed TEC over KGNI, TCMS, YONS, and BJFS GPS receiver stations. The data plotted are those on the days of the study period.