Sensitivity Analysis of Discharge in the Arctic Usa Basin, East-European Russia

The high sensitivity of the Arctic implies that impact of climate change and related environmental changes on river discharge can be considerable. Sensitivity of discharge to changes in precipitation, temperature, permafrost and vegetation, was studied in the Usa basin, Northeast-European Russia. For this purpose, a distributed hydrological model (RHINEFLOW) was adapted. Furthermore, the effect of climate change simulated by a GCM (HADCM2S750 integration) on runoff was assessed, including indirect effects of permafrost thawing and changes in vegetation distribution. The study shows that discharge in the Usa basin is highly sensitive to changes in precipitation and temperature. The effect of precipitation change is present throughout the year, while temperature changes affect discharge only in seasons when temperature fluctuates around the freezing point (April and October). Discharge is rather sensitive to changes in vegetation. Sensitivity to permafrost occurrence is high in winter, because infiltration and consequently base flow increases if permafrost melts. The effect of climate change simulated by the scenario on discharge was significant. Peak flow can both decrease (by 22%) and increase (by 19%) comparedwith present-day, depending on the amount of winter precipitation. Also, runoff peaks earlier in the season. These results can have implications for the magnitude and timing of the runoff peak, break-up and water-levels.     

Changes in the resources and reserves of subsoil waters in the permafrost zone of Pechora-Ural Region under climate warming

Climate-warming-induced changes in the natural resources and the storage reserves of phreatic waters in zones of massive-insular, discontinuous, and continuous permafrost in the region are discussed. The relationship between a long-term trend toward rise in the phreatic water table and an increase in the period of their infiltration recharge is substantiated. The increments of phreatic-water natural resources typical of hydrogeological subdivisions of the region over a many-year period are evaluated. It is shown that the natural resources and storage reserves of phreatic waters in taliks increase almost over the entire territory of the Pechora-Ural Region.