Changes in Hydrological Extremes for Sub-Arctic catchment in Finland

Abstract

Climate change has been associated with increased frequency in the occurrence of extreme precipitation. These extreme events are in turn linked to peak discharges and flood events. In the Nordic region, peak discharges in unregulated rivers occur during spring snowmelt thereby posing a challenge in attributing extreme precipitation events to peak discharges. This study aims to assess the effect of extreme events on hydrological river flows by analysing the timing and intensity of extreme precipitation events (highest 1-day precipitation RX1day, highest 5-day precipitation RX5day and maximum consecutive wet days (CWD)) with river discharges using a sub-Arctic catchment. Using a calibrated Hydrologiska Byråns Vattenbalansavdelning (HBV) model, we analyse changes in discharge occurring as a result of these extremes. By analysing the relationship between extreme precipitation, and the resulting river discharges, findings from the study provide a valuable insights and basis to predict the effect of extreme precipitation events on river flows.