Hydrological and Meteorological Variability in the Volga River Basin under Global Warming by 1.5 and 2 Degrees

Abstract

The idea of the research to assess the impact of 1.5 °C and 2 °C global warming in the 21st century on the runoff formation in the Volga basin corresponds to the Paris agreement on climate change 2016 with the main goal to keep the global air temperature rise to below 2 °C relative to the pre-industrial level and to take measures to limit warming to 1.5 °C by the end of the 21st century. The purpose of this study was to obtain physically based results of changes in the water regime of the Volga basin rivers under global warming by 1.5 °C and 2 °C relative to pre-industrial values. The physical and mathematical model of runoff generation ECOMAG (ECOlogical Model for Applied Geophysics) was applied in calculations using data from global climate models (GCMs). The estimation of flow anomalies of the Volga River and its major tributaries showed a decrease in annual runoff by 10–11% relative to the period from 1970 to 1999. The largest relative decrease in runoff by 17–20% was noted for the Oka and Upper Volga rivers, while the Kama River had only a 1–5% decrease. The Volga winter runoff increased by 17% and 28% under global warming by 1.5 °C and 2 °C, respectively, and negative runoff anomalies during the spring flood and the summer–autumn period turned out to be in the range of 21 to 23%. Despite the increase in precipitation, the role of evaporation in the water balance of the Volga basin will only increase.

Water Flow Changes In The Don River (European Russia) During 1891–2019

“…Evidently, the naturalization procedure for water flow should include a set of methods, including hydrological models that describe hydrological processes with various level of detail (Motovilov et al 1999;Kalugin 2022).…”

Spatiotemporal Evaluation of the Flood Potential Index and Its Driving Factors across the Volga River Basin Based on Combined Satellite Gravity Observations

“…The VRB is mainly affected by the continental climate, and is cold and snowy in winters and warm and humid in summers. The upper, middle and right bank of the lower reaches have a forest climate, the left bank of the lower reaches has a steppe climate and semi-desert climate, and the Caspian Sea lowland has a desert climate [40]. Annual PPT is 635 mm in the northwest and 305 mm in the southeast.…”

“…The main sources of river recharge in the basin are PPT, GW, glacier melt, snow melt and lake water [62]. Since the VRB is located in the middle and high latitude region, its water source comes from snowmelt (60%), GW (30%) and PPT (10%) [40]. Figure 12a shows that the correlations between SWE, GW and the FPI are much stronger than the ones between PPT and the FPI.…”

“…The Volga River is situated in southwestern Russia, with a total length of 3692 km, and is the longest inland river with the widest basin in the world [40]. Since records began, there have been 20 floods in the Volga River basin (VRB) (the water level was 11-13 m higher than the average water level in many years) [41].…”

Projected changes in precipitation and air temperature over the Volga River Basin from bias-corrected CMIP6 outputs

“…Kalugin (2022) used the precipitation and temperature outputs of two CMIP5-GCMs, including GFDL-ESM2M and MIROC5, over the Volga River basin to assess climate change impacts on the Volga River runoff in the 21st century. Kalugin (2022) reported that in the projected global warming scenarios of 1.5°C and 2°C by 2045 and 2064, the Volga basin could experience mean annual air temperature increases of 2.5 °C and 3.4 °C, respectively. Annual precipitation in the Volga basin increases by 8% at 1.5 °C global warming and averages 11% at 2 °C global warming.…”