# On a Novel Approach to Correcting Temperature Dependencies in Magnetic Observatory Data
## 4 Temperature Correction of Data
### Data for February 2021
At the end of the localization interval, where such binding was missing, an additional extension was formed, on which a smooth merging with the neighboring data fragment was further performed. The overall localization interval was thereby split into the following segments: the left-hand extension LS (if merging was required on the left), the inner segment IS, and the right-hand extension RS (if merging was required on the right). For proper merging, the inner boundary of the extension (i.e., the right end of the LS segment and/or the left end of the RS segment) must correspond to the point of a local extremum on the \(a+bT\) function. All such extrema located outside the area of the \(a+bT\) transition through zero were automatically marked by the algorithm. In Figures 6 and 8, they corresponded to the ends of the green segments. The outer boundary of extension (i.e., the left end of the LS segment and/or the right end of the RS segment) where the correction should reduce to zero was determined by the nearest date of the absolute measurement. Within the IS segment, the correction was carried out as usual. On extension, the merging was performed by reducing the correction term to zero linearly (the formula is given for the RS segment):  
Figure 6.3  
where \(VC(t)\) is the correction term at time \(t\); \(t_{0}\), \(t_{1}\) are the left and right boundaries of the RS segment, respectively (for the LS segment, the calculations were similar). As discussed above, in our case, such a merging was only required on the right side. In Figure 8, the most appropriate boundaries for the IS segment were defined by the central green interval--its left end coincided with the \(a+bT\) zero crossing, while the right end corresponded to the local extreme of \(a+bT\) (2021-06-21 19:40:00), being the left boundary of the RS segment. The right boundary of the RS segment corresponded to the right end of the red interval (2021-06-29 00:00:00). When calculating the correlation coefficients on the IS segment, the following values were obtained by the algorithm: \(a=-3.9925\) and \(b=0.2019\). Their previous values corresponding to the \(a+bT\) plot in Figure 8 were \(a=-3.385\) and \(b=0.2119\). As a result, the graph \(a+bT\) shifted down by \(\delta a=-3.385+3.9925=0.6075\) relative to its position in Figure 6.4 The coefficient \(b\) also changed insignificantly by \(\delta b=0.2119\,-\,0.2019=0.01\). As a result, the left boundary of the IS segment corresponding to the transition through 0 of the new graph \(a+bT\) shifted to the right at the time 2021-06-20 19:40:00. The obtained correlation parameters and the localization interval were manually set in the spc.txt file as follows:  
\"m2021-06;2021-06-20 19:40:00; 2021-06-21 19:40:00 * 2021-06-29 00:00:00; \(-3.9925\); 0.2019\". Here, the two time stamps separated by an asterisk denoted the RS segment boundaries. So, with this line assignment in the spc.txt file for June 2021, the temperature correction was performed only on the rather short localization interval depicted in Figure 8 by the yellow segment. After the jump in the \(G\)-_mean_(G) plot and outside this interval, the temperature correction was performed successfully by a daily smoothed baseline. Figure 9 shows the \(G\) graph based on the adjusted variations, but original baseline values, in June 2021 (blue color). As in February, some biases in its behavior still remained. These were corrected by computing the new observed baseline values, here referring to the absolute measurements of 16, 22, and 29 June 2021. The final graph \(G\), based on the fully recalculated data for June 2021, is shown in orange in Figure 6.5