Climate changes in river flow and precipitation in the White Sea Region

On the basis of observational and reanalyzed data containing more than 60 years of time series, the authors studied climate changes and inter-annual variability of river flow, precipitation, soil and atmospheric moisture in the White Sea region. As an object of study, they consider the White Sea region — a territory that includes a square within 61°—70° NL and 30°—46° EL. The authors used open resources of Roshydromet, as well as various reanalysis data. For all the studied rivers of the White Sea catchment area, there are positive trends in the change in their flow (on average 11% for the period 1955—2019). This may be due to the observed increase in precipitation in the region over the same calculation period. A significant increase in precipitation has been established since the mid-1970s until 2021. Changes in the amount of precipitation in the White Sea area over the period of satellite observations (1980—2021), estimated by a linear trend, are unevenly distributed. In the northeast and southwest of the region under consideration, there is a decrease in average daily precipitation by –0.02 kg/m2 over 10 years. This decrease is several times less in absolute value than the increase in precipitation in the central part of the study area — by about +0.06 kg/m2 over 10 years. As a result, there has been an overall increase in precipitation throughout the region. The study shows that this growth is most pronounced in the areas of Kandalaksha and Dvina Bays, as well as in the catchment area of the Northern Dvina River. The authors assume that the observed increase in precipitation may be due to the increased influence of the North Atlantic and the Arctic Ocean on the White Sea region. The performed spectral and wavelet analysis revealed fluctuations in the studied parameters with periods of 2—4 years and 12—14 years. Via cross-wavelet analysis, the authors show the relationship between the inter-annual variability in the amount of precipitation in the White Sea region and the North Atlantic and Arctic oscillations.