# Ionospheric Weather at Two Starlink Launches during Two-Phase Geomagnetic Storms
## 2 Data Processing Results
The JPLR-based _GEC_ is provided in all four panels for comparison with other data. The difference between JPLR 'true' _GEC_ and 1- and 2-day JPLR-based forecast by IZMIRAN (JPLR1 and JPLR2) [10] brought to light some differences, as they can be seen in Figure 4a. Similar differences are observed between CODE 'true' data and CODE1/CODE2 forecast (Figure 4b) [12], CASG 'true' data and CASG1/CASG2 forecast (Figure 4c) [14], and BUAG 'true' and B1 PG/B2 PG forecast (Figure 4d) [13]. The UPC-IonSAT produces UQRG and real-time UADG on a 15 min cadence [16; 27], but only hourly _GEC_ derived from them are used in the present study, similar to other kinds of 'true' GIMs. Note the close resemblance of hourly UQRG and real-time UADG-based results (Figure 4a) but the difference of their 'true' profiles from JPLR, which is also seen for CODE (Figure 4b), CASG (Figure 4c) and BUAG (Figure 4d) (in agreement with long-term comparisons, Figure 2 of [27], Figure 6 of [28] and Figure 3 of [29]). It has been noted that the density of the neutral atmosphere was increased up to 50% during the geomagnetic storm on 3-4 February 2022, increasing drag of the satellites and dooming most of them [2; 3; 4; 5; 6; 7; 8]. To check a possible increase of _GEC_ magnitude during the storm, we compare the peak magnitude \(GEC_{max}\) after the Starlink launch with the base daily-average quiet value \(GEC_{av}\) on the presstorm day. Table 2 provides these parameters for the different data centers after the Starlink launches on 3 February and 7 July 2022. The increment of the global electron content is calculated in percent, \(dGECp\), with Equation (3):  
\[dGECp=\frac{GEC_{max}\ -GEC_{av}}{GEC_{av}}\ \times\ 100\% \tag{3}\]  
Figure 3: Global electron content (_GEC_) in daily–hourly UT frame produced from the UPC UQRG: (**a**) February 2022; (**b**) July 2022. Starlink S-36 and S-49 launches (star). We observe in Table 2 that the \(GEC\) increment varies from 10 to 24%, accompanying the neutral density increase [2; 3; 4; 5; 6; 7; 8] for both events. This characteristic presents a measure of the positive \(GEC\) intensification for the second phase of the ionosphere storm. To estimate quantitative agreement/disagreement between the different data, we determine the coefficient of determination (\(R\)-squared or \(R^{2}\)) as a measure of the difference \begin{table}
\begin{tabular}{c c c c c c c c} \hline \multicolumn{2}{c}{**Data Center**} & **JPLR** & **CODE** & **BUAG** & **CASG** & **UQRG** & **UADG** \\ \hline \multicolumn{2}{c}{**Date**} & \multicolumn{6}{c}{**3 February 2022**} \\ \hline \(GEC_{\textit{air}}\) & 2 February 2022 & 1.23 & 1.13 & 1.09 & 1.09 & 1.14 & 1.09 \\ \hline \(GEC_{\textit{max}}\) & 4 February 2022 & 1.48 & 1.34 & 1.33 & 1.25 & 1.38 & 1.35 \\ \hline \(dGECp\), \% & & 20.3 & 18.6 & 22.0 & 14.7 & 21.0 & 23.9 \\ \hline \multicolumn{2}{c}{**Date**} & \multicolumn{6}{c}{**7 July 2022**} \\ \hline \(GEC_{\textit{air}}\) & 6 July 2022 & 1.06 & 0.92 & 0.96 & 0.92 & 0.95 & 0.92 \\ \hline \(GEC_{\textit{max}}\) & 8 July 2022 & 1.24 & 1.09 & 1.06 & 1.06 & 1.11 & 1.08 \\ \hline \(dGECp\), \% & & 17.0 & 18.5 & 10.4 & 15.2 & 16.8 & 17.4 \\ \hline \end{tabular}
\end{table} 
Table 2: Peak \(GEC\) after Starlink launch and its increase in dGEC (%), regarding the daily mean ‘base’ \(GEC_{\textit{air}}\) for the presstorm day. Figure 4: Daily–hourly variation of \(GEC\) and geomagnetic indices for February 2022. The Starlink S-36 launch (thick vertical line). **(a)** JPLR—based ‘true’ \(GEC\), 1- and 2-day forecast (JPLR1/JPLR2) produced by IZMIRAN, ‘true’ UQRG and UPC tomographic-kriging real-time UADG \(GEC\) products; **(b)** CODE ‘true’ \(GEC\) and CODE1/CODE2 forecast; **(c)** CASG ‘true’ data and CASG1/CASG2 forecast; **(d)** BUAG ‘true’ and B1 PG/B2 PG forecast; **(e)** geomagnetic Hpo index; **(f)** equatorial Dst index.