Data for detecting trends in hydroclimatic changes in the Svartberget Krycklan catchment

Here we use a climate time series from the Krycklan catchment to detect corresponding changes in seasonal runoff in a boreal catchment in Northern Sweden. To do this, we have used 40 years of temperature and precipitation data to categorised into seasons to detect extreme climate indices. Significant changes were observed particularly in the winter with eight indices indicating winters are becoming warmer. Looking at runoff, we have observed increasing baseflow during the winter but decreasing baseflow during the summers. Using the significant climate indices to predict the changes in runoff variability across the 40 years indicated that warmer winters increase winter baseflow but exhaust the water stored to sustain summer baseflow. We verified this using isotope data which showed that stream water reflect winter precipitation signals while summer baseflow had decreasing winter signals. These findings are important for understanding future changes in boreal climate and how catchments water will be affected by the redistribution of season flow.