The Past and Future Estimates of Climate and Streamflow Changes in the Western Dvina River Basin

Abstract

The study presents an assessment of the recent and projected changes of the middle and upper Western Dvina River runoff and regional climate during the 20th and 21st centuries. For this assessment, we used historical runoff data, the output of EURO-CORDEX consortium calculations for scenarios RCP4.5 and RCP8.5, and hydrological model "Hydrograph." Analysis of monthly runoff data for the 1945-2015 period revealed positive trends for each of the five months from December to April. These trends are statistically significant at the 0.05 level. No significant trends were found for other months. Significant negative trends were established for spring flood peak discharges (from −69 to −88 m 3 s −1 per 10 years). Usually, maximum discharges are observed during spring floods. Minimum discharges during winter low-water period were increased by 6 m 3 s −1 per 10 years. The annual runoff trend was statistically significant only at the Polotsk gauging station (9.5 m 3 s −1 per 10 years). To the end of the current century over the study region, estimates of projected meteorological parameters (air temperature and precipitation) show positive tendencies of air temperature (from 2.4 • C to 4.7 • C depending on scenario) and precipitation (up to 15 to 30 mm). Changes of seasonal and annual temperature and precipitation vary depending on the models and scenarios used. The strongest changes were noticed for the RCP8.5 scenario. The greatest changes within each scenario were revealed for the winter and spring seasons. It is projected that during the 2021-2100 period according to both RCP scenarios, annual discharges will not change in the upper part of the Western Dvina River Basin and increase by 10-12% in its lower part. The maximum spring flood discharges in both RCP scenarios are expected to decrease by 25%. The minimum runoff of winter lowflow period is expected to increase by up to 60 to 90% above the present long-term mean values.

Proglacial icings as records of winter hydrological processes

“…We thus test four other methods that potentially are able to provide complementary information on parent sources responsible for icing formation. These indirect methods are all based on the principle that waters originating from different sources present unique hydrochemical and isotopic signatures as a result of the specific hydrological, geological, and biological processes they have been exposed to (Drever, 1997). We hypothesize that comparing the hydrochemical signatures of icing water and cryogenic precipitates to those of other hydrological sources can provide insights into the sources that contributed to icing formation.…”

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Natural Hazards and Extreme Events in the Baltic Sea region

“…(Stahl et al, 2010;Poljanšek et al, 2017;Gudmundsson et al, 2017). There are local and regional studies generally supporting this broader picture (Valiukas et al, 2011;Przybylak et al, 2007;Stonevičius et al,2018;Danilovich et. al., 2019).…”

Changes of Hydrological Extremes in the Center of Eastern Europe and Their Plausible Causes

“…Over most of Belarus, the monthly river discharges increased significantly in January-March [24,39]. The same changes occurred in most of the Baltic Sea Basin rivers [40][41][42].…”