Spatial, Temporal and Forecast Evaluation of Rivers’ Streamflow of the Drainage Basin of the Upper Tisa under the Conditions of Climate Change
The drainage basin of the Upper Tisa is considered to be one of the most flood hazardous areas of the Ukrainian Carpathians. Climate changes in the past decade made a significant impact on the course of hydrological processes, including streamflow. The studies of the processes at global and regional levels are of great importance for grounding of flood protection operations as well as arrangement of measures for adaptation to climate change.
The study considers approaches to evaluation of changes of hydrologic balance elements of the investigated drainage basin in the period of the 20th century. A retrospective analysis of the changes is provided in order to find out relationship between the streamflow and the climate aspects which influence it. A statistical analysis of a series of long-term observations was performed in order to test their steadiness and homogeneity. Inter-row connections were determined between changes in precipitation regime, air temperature of the surface and streamflow in the modern period (1991–2012) compared to the period of the climatic norm (1961–1990). The closest interconnection between mentioned variables is observed for the warm period. For the cold period such dependencies are satisfactory. Consequently, an equation was derived for conversion of the expected influence of climate change on the streamflow.
Results of the regional model REMO-ESNAM5 were used to perform forecast evaluation of hydrological consequences of climate change. The projection of changes of climatic aspects for the drainage basin of the Upper Tisa for the time period 2021–2050 as well as А1B sustainable development scenario was created. The evaluation of possible changes of average, seasonal and annual streamflow in the basin is presented up to the middle of the 21st century. Annual redistribution is clearly registered. Forecast evaluations were performed of the maximum streamflow changes, floods frequency and their recurrence throughout the year.