# Towards a Real-Time Description of the Ionosphere:
## 7 Validation Results for _Inm_F2 Based on Ground-Based Ionosonde Observations
### Statistics on the Full Dataset
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Ionosonde Stations Dataset** & **Model** & **Res. Mean** & **RMSE** & **NRMSE** & **R** & **Counts** \\ \hline \multirow{2}{*}{Daytime} & IRI & \(-6.736\) & 27.844 & 11.021 & 0.807 & \multirow{2}{*}{4,091,455} \\  & IRTAM & \(-3.142\) & 24.745 & 9.794 & 0.855 & \\ \hline \multirow{2}{*}{Nighttime} & IRI & 10.293 & 38.663 & 12.625 & 0.580 & \multirow{2}{*}{4,198,762} \\  & IRTAM & 0.428 & 31.143 & 10.170 & 0.745 & \\ \hline \multirow{2}{*}{Solar terminator} & IRI & 1.424 & 29.298 & 11.088 & 0.722 & \multirow{2}{*}{1,843,770} \\  & IRTAM & \(-2.901\) & 27.034 & 10.231 & 0.784 & \\ \hline \multirow{2}{*}{March Equinox} & IRI & 2.693 & 30.997 & 11.096 & 0.788 & \multirow{2}{*}{2,710,599} \\  & IRTAM & \(-1.338\) & 26.225 & 9.388 & 0.859 & \\ \hline \multirow{2}{*}{June Solstice} & IRI & \(-5.670\) & 34.761 & 12.768 & 0.743 & \multirow{2}{*}{2,255,233} \\  & IRTAM & \(-2.196\) & 29.699 & 10.908 & 0.825 & \\ \hline \multirow{2}{*}{September Equinox} & IRI & 1.607 & 30.758 & 11.154 & 0.784 & \multirow{2}{*}{2,644,252} \\  & IRTAM & \(-1.798\) & 26.638 & 9.660 & 0.849 & \\ \hline \multirow{2}{*}{December Solstice} & IRI & 7.735 & 35.608 & 12.723 & 0.765 & \multirow{2}{*}{2,523,903} \\  & IRTAM & \(-1.217\) & 29.494 & 10.539 & 0.844 & \\ \hline \multirow{2}{*}{LSA} & IRI & 1.581 & 32.216 & 12.481 & 0.725 & \multirow{2}{*}{3,782,579} \\  & IRTAM & \(-2.231\) & 28.479 & 11.034 & 0.804 & \\ \hline \multirow{2}{*}{MSA} & IRI & 4.591 & 33.831 & 12.081 & 0.736 & \multirow{2}{*}{3,801,672} \\  & IRTAM & \(-0.750\) & 28.283 & 10.100 & 0.829 & \\ \hline \multirow{2}{*}{HSA} & IRI & \(-2.019\) & 32.867 & 10.943 & 0.757 & \multirow{2}{*}{2,549,736} \\  & IRTAM & \(-2.006\) & 26.689 & 8.886 & 0.853 & \\ \hline \multirow{2}{*}{Quiet magnetic activity} & IRI & 0.682 & 31.877 & 11.593 & 0.772 & \multirow{2}{*}{9,147,468} \\  & IRTAM & \(-1.580\) & 27.402 & 9.966 & 0.845 & \\ \hline \multirow{2}{*}{Moderate magnetic activity} & IRI & 11.754 & 41.017 & 13.914 & 0.720 & \multirow{2}{*}{959,046} \\  & IRTAM & \(-1.983\) & 32.279 & 10.950 & 0.832 & \\ \hline \multirow{2}{*}{Disturbed magnetic activity} & IRI & 28.087 & 66.786 & 20.793 & 0.595 & \multirow{2}{*}{27,473} \\  & IRTAM & \(-1.683\) & 45.640 & 14.210 & 0.807 & \\ \hline \multirow{2}{*}{Full dataset} & IRI & 1.804 & 32.993 & 11.912 & 0.766 & \multirow{2}{*}{10,133,987} \\  & IRTAM & \(-1.619\) & 27.965 & 10.097 & 0.845 & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: _Res. Mean, RMSE, NRMSE, and R values calculated for the IRI and IRTAM models on the basis of the \(hm\)F2 ground-based ionosondes observations, for the bins defined in Section 4.2, according to the three levels of solar activity defined in Section 3.1, and for the full dataset (bottom row). The number of counts on which the statistics were calculated is reported in the rightmost column._Table 6 shows the statistical parameters (1-4) calculated for the _hm_F2 time series recorded in each of the 40 ionosonde stations listed in Table 1. Differently from the _fo_F2 results shown in Table 3, the number of cases for which _Res.Mean_\({}_{\rm IRI}\) < _Res.Mean_\({}_{\rm IRATAM}\) and for which _Res.Mean_\({}_{\rm IRATAM}\) < _Res.Mean_\({}_{\rm IRI}\) is practically the same. This circumstance is in accordance with the very similar IRI (1.804 km) and IRATAM (\(-\)1.619 km) _Res.Mean_ absolute values calculated when the whole _hm_F2 ionosonde dataset is considered (bottom row of Table 5). This fact points out that the two models are practically equivalent in terms of accuracy. Nonetheless, the IRTAM _RMSE_ and _NRMSE_ values are always lower than the IRI ones, with the exception of the stations of Anyang and I-Cheon, Kwajalein, and Rome. This fact highlights that IRTAM models _hm_F2 with a precision better than that of IRI.