# Ionospheric Weather at Two Starlink Launches during Two-Phase Geomagnetic Storms
## 2 Data Processing Results
between the 'true' data (\(Y\)) and forecast of \(GEC\) (X) or between the different 'true' data (\(X\) and \(Y\)) [32]:  
\[R^{2}=1-\frac{\sum_{i}^{m}(X_{i}-Y_{i})^{2}}{\sum_{1}^{m}(Y_{av}-Y_{i})^{2}} \tag{4}\]  
where  
\[Y_{av}=\frac{1}{m}{\sum_{1}}^{m}Y_{i} \tag{5}\]  
The \(R^{2}\) varies from \(-\infty\) to 1 (worst value = \(-\infty\); best value = +1), so \(R^{2}\) = 1 presents the best resemblance of two data sets. This feature makes it easy to allocate a reasonable agreement with \(R^{2}\) > 0.5. The root-mean-square (\(RMS\)) deviation (in GECU) is also calculated:  
\[RMS=\sqrt{\frac{1}{m}{\sum_{1}}^{m}(X_{i}-Y_{i})^{2}} \tag{6}\]  
The results of \(R^{2}\) and \(RMS\) calculation for the different monthly sets of \(GEC\) are provided in Table 3 for February and July 2022. The best agreement between the pairs with \(R^{2}\) > 0.5 is given in bold. JPLR 'true' profiles show an unacceptable difference with all data reviewed except UQRG in July 2022. Variations of 'true' profiles are very similar, as can be seen in Figure 4, but the absolute values of JPLR \(GEC\) are greater than any other 'true' profile. Since Yav (Equation (5)) is calculated from JPLR \(GEC\) (the 1 st line in Table 3 for February and the 1 st line for July), it yields the negative \(R^{2}\) (Equation (4)), attesting to the poor agreement with other GIMs. Poor \(R^{2}\) is also obtained for all other indices regarding JPLR \(GEC\) in the 1 st column of Table 3, when Yav (Equation (5)) is calculated from the other indices. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**JPLR**} & \multicolumn{3}{c}{**Code**} & \multicolumn{3}{c}{**BUAG**} & \multicolumn{3}{c}{**CASG**} & \multicolumn{3}{c}{**UQRG**} & \multicolumn{3}{c}{**UADG**} \\ \hline
**X** & **Obs** & **d1** & **d2** & **Obs** & **d1** & **d2** & **Obs** & **d1** & **d2** & **Obs** & **d1** & **d2** & **Obs** & **Obs** & \\ \hline
**Y** & \multicolumn{3}{c}{**February 2022**} & & & & & & & & & & & & & \\ \hline JPLR & – & \(-0.05\) & \(-0.22\) & \(-1.35\) & \(-2.20\) & \(-2.82\) & \(-3.01\) & \(-3.04\) & \(-3.08\) & \(-3.13\) & \(-2.22\) & \(-2.69\) & \(-1.40\) & \(-3.41\) & \(R^{2}\) \\  & \(0.073\) & \(0.079\) & \(0.109\) & \(0.126\) & \(0.138\) & \(0.142\) & \(0.142\) & \(0.143\) & \(0.144\) & \(0.127\) & \(0.136\) & \(0.110\) & \(0.149\) & RMS \\ \hline CODE & \(-1.57\) & \(-2.31\) & \(-2.42\) & \(-\) & \(-0.25\) & \(-0.20\) & \(\mathbf{0.667}\) & \(-0.374\) & \(-0.68\) & \(\mathbf{0.631}\) & \(0.074\) & \(-0.12\) & \(\mathbf{0.684}\) & \(\mathbf{0.661}\) & \(R^{2}\) \\  & \(0.109\) & \(0.123\) & \(0.126\) & & \(0.076\) & \(0.074\) & \(\mathbf{0.039}\) & \(0.080\) & \(0.088\) & \(\mathbf{0.041}  
The 'true' data of CODE, BUAG, CASG and UQRG are in agreement during February and July in most cases. The 'true' UQRG and UADG show agreement with 'true' data of other centers except UQRG-JPLR and UADG-UQRG, but they show no agreement with 'forecast' data in February. The agreement is best for UQRG with other data sets in July except for JPLR1 and JPLR2 forecast. The next successful agreement is UADG in July except for JPLR 'true', IZMIRAN 1- and 2-day forecasts of JPLR1 and JPLR2, and CODE d1, BUAG d1 and d2, and CASG d1 and d2 forecasts. Though some 'forecasts' agree with the 'true' UQRG and UADG data, these are not supposed to be used together in practice. In general, there is only one case of the agreement of CASG 'true' data with the relevant 1-day (d1) 'forecast' in July based on GIMs from the same source. At the same time, we observe an agreement between the different 'true'-'true' data pairs, confirming the previous results of comparisons of the different GIMs [27; 28; 29]. Recognizing that there are no 'true' _GEC_ profiles nor 'true' GIMs by the time of the Starlink launches, we proceed to the evaluation of GIMs forecast by comparison of _GEC_ (as a product of GIM) with 'true' _GEC_ during two storms. The 'true' (Obs.)