## 3 Results
### Layer-by-Layer Analysis of Snowpack, Data of Experiments  
Figure 2 shows the change in the isotopic composition of water in the isolated 11 snow layers (from the bottom to the upper), which were taken out of the barrel at the end of winter 2019-2020 (Experiment No 1; site III, Figure 1c). For comparison, the figure shows the precipitation-weighted mean values of water isotopic composition in the event-based snowfalls and the average daily air temperature calculated for the same period as the layers of snow were formed in the barrel. The figure shows that the changes in \(\delta^{18}\)O and 8D in the layers of snow and in the precipitation-weighted mean value of snowfalls correlate well both with each other and with the change of the average daily temperature. At the same time, significant differences in the isotopic composition between the isolated layers of snow and the initial compositions of snowfalls are observed at the moments of a sharp increase in air temperature, when lighter water isotopes condensed at lower temperatures can sublimate from the layer of snow back into the atmosphere even under the separating plastic disk (along its edges). This situation was observed for layers 3, 8, and 9 (Figure 2). In addition, lower values of deuterium excess in these snow layers relative to the initial snowfalls indicate the existence of isotopic fractionation of snow in them. The results of experiments to study changes in the isotopic composition of the water in the initial snow precipitation, during their storage in the layers of snow cover in the winter of 2020-2021 (experiment No. 2), are shown in Figure 3. To display all results at once, we used a single scale, where the value of the water equivalent of each layer is the arithmetic mean of the components of the figure since the water equivalents of the identified layers of snow in barrels (experimental sites I and II, Figure 1c) and snow precipitation sampled for a similar period (site III, Figure 1c) differ no more than by 25%. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Depth, mm w. Eq.**} & \multicolumn{2}{c}{\(\delta^{18}\)O, \%\(\%\)} & \multicolumn{2}{c}{**8D, \%\(\%\)**} & \multicolumn{2}{c}{**D-Excess, \%\(\%\)**} \\ \cline{2-7}  & **1** & **2** & **1** & **2** & **1** & **2** & **1** & **2** \\ \hline \multicolumn{7}{c}{Frozen soil (n = 8): sampling points [1] 2, 4, 5, 6, 7, 9, 10, 13} \\ \(\max\) & 155 & 20 & \(-19.1\) & \(-17.7\) & \(-147.2\) & \(-134.6\) & 6.4 & 9.8 \\ \(\min\) & 78 & 14 & \(-21.9\) & \(-20.8\) & \(-170.3\) & \(-158.0\) & 2.4 & 4.4 \\ mean [2] & 129 & 18 & \(-20.3\) & \(-19.5\) & \(-158.0\) & \(-149\) & 5 & 7 \\ SDOM [3] & & & 0.6 & 0.7 & 4.3 & 5.9 & 1.0 & 1.1 \\ \multicolumn{7}{c}{No soil freezing (n = 6): sampling points [1] 1, 3, 8, 11, 12, 14} \\ \(\max\) & 180 & 23 & \(-18.6\) & \(-14.1\) & \(-144.6\) & \(-113.0\) & 5.8 & 3.5 \\ \(\min\) & 134 & 17 & \(-21.7\) & \(-16.6\) & \(-168.5\) & \(-130.3\) & 3.4 & -1.9 \\ \(\mean\) [2] & 162 & 21 & \(-20.0\) & \(-15.5\) & \(-155\) & \(-122\) & 5 & 1 \\ SDOM [3] & & & 0.8 & 0.9 & 7.0 & 5.3 & 0.7 & 1.6 \\ \multicolumn{7}{c}{Atmospheric precipitation (snow n = 47; rain n = 12)} \\ snow [4] & 150 & 33 & \(-19.2\) & \(-17.8\) & \(-147.4\) & \(-133.5\) & 6 & 9 \\ rain [5] & & 48 & \(-10.9\) & & \(-88.9\) & & \(-2.1\) \\ SDOM [3] & & & 0.1 & 0.1 & 0.4 & 0.4 & 0.8 & 0.8 \\ \hline \multicolumn{7}{c}{\({}^{1}\) number according to Figure 1b; [2] arithmetic mean for the depth; depth-weighted mean for \(\delta^{18}\)O, \(\delta\)D, d-excess; \({}^{3}\) SDOM—standard deviation of the mean; [4] precipitation-weighted mean for the same period as the snowpack layers; [5] precipitation-weighted for the last two months before snow cover.} \\ \end{tabular}
\end{table} 
Table 2: Comparison of the isotopic composition of the bulk snowpack samples (1) with the bottom layer of the snowpack (2) depending on the soil freezing in winter 2019–2020.