Трансформация водного режима верховых болот в условиях изменения климата на примере Северо-Западного региона

The study examines changes in climatic and hydrological characteristics based on long-term observations of swamps in the North-West region of Russia. It is shown that the increase in air temperature, especially during the winter period, as well as the intra-annual redistribution of atmospheric precipitation, lead to changes in the water level regime and runoff from the swamps. The analysis was conducted by identifying quasi-stationary periods using the method of detecting breakpoints in the series of mean annual air temperatures. The beginning of the first quasi-stationary period is determined by the begining of observations and varies from 1952 to 1956. Its end and the beginning of the second quasi-stationary period for the swamps of the Leningrad region, based on the analysis of mean annual air temperatures, occurred in 1986–1987, while for the Arkhangelsk region, it occurred 15 years later, in 2002. During the second period, a general trend of decreasing water table depths was observed in the Leningrad region. The volume of runoff from the swamps remained almost unchanged, while the maximum discharge of spring floodwater decreased by half, and its onset shifted to earlier dates. The number of cases of channel freezing during the winter period decreased by 27%. In the Arkhangelsk region, an increase in bog water levels was observed on ridge-hollow microlandscapes, particularly during the winter period. On ridge-pool microlandscapes, the water level slightly decreased. The water runoff from the swamps increased during the second period. The onset date of the spring flood did not change, but the maximum water discharges decreased by 26%, and unlike the earlier period, water runoff did not cease during winter and summer low-water periods.

Key words: peatland, swamp, water regime, water table depth, runoff