Climatic Controls on Mean and Extreme Streamflow Changes Across the Permafrost Region of Canada

• Main Authors: Rajesh R. Shrestha, Jennifer Pesklevits, Daqing Yang, Daniel L. Peters, Yonas B. Dibike
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: Water
• Subjects: climatic controls; multiple linear regression; permafrost region; streamflow extremes; trend analysis; variable importance analysis
• Online Access: https://www.mdpi.com/2073-4441/13/5/626

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_mean), minimum flow (Q_min), maximum flow (Q_max) and Q_max 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_min for 43% of stations as the most prominent trend, and a relatively smaller number of stations with significant Q_mean, Q_max and Q_max 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_mean and seasonal precipitation, and a negative correlation between Q_mean and seasonal temperature. The basin-averaged streamflow, precipitation and temperature trends showed weak correlations that included a positive correlation between Q_min and October to March precipitation trends, and negative correlations of Q_max 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_mean and Q_max, and temperature on Q_min. 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.