| Summary: | Climatic change is affecting streamflow regimes of the permafrost region, altering mean and extreme streamflow conditions. In this study, we analyzed historical trends in annual mean flow (Q<sub>mean</sub>), minimum flow (Q<sub>min</sub>), maximum flow (Q<sub>max</sub>) and Q<sub>max</sub> timing across 84 hydrometric stations in the permafrost region of Canada. Furthermore, we related streamflow trends with temperature and precipitation trends, and used a multiple linear regression (MLR) framework to evaluate climatic controls on streamflow components. The results revealed spatially varied trends across the region, with significantly increasing (at 10% level) Q<sub>min</sub> for 43% of stations as the most prominent trend, and a relatively smaller number of stations with significant Q<sub>mean</sub>, Q<sub>max</sub> and Q<sub>max</sub> timing trends. Temperatures over both the cold and warm seasons showed significant warming for >70% of basin areas upstream of the hydrometric stations, while precipitation exhibited increases for >15% of the basins. Comparisons of the 1976 to 2005 basin-averaged climatological means of streamflow variables with precipitation and temperature revealed a positive correlation between Q<sub>mean</sub> and seasonal precipitation, and a negative correlation between Q<sub>mean</sub> and seasonal temperature. The basin-averaged streamflow, precipitation and temperature trends showed weak correlations that included a positive correlation between Q<sub>min</sub> and October to March precipitation trends, and negative correlations of Q<sub>max</sub> timing with October to March and April to September temperature trends. The MLR-based variable importance analysis revealed the dominant controls of precipitation on Q<sub>mean</sub> and Q<sub>max</sub>, and temperature on Q<sub>min</sub>. Overall, this study contributes towards an enhanced understanding of ongoing changes in streamflow regimes and their climatic controls across the Canadian permafrost region, which could be generalized for the broader pan-Arctic regions.
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