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

• Published in: Water
• Main Authors: Rajesh R. Shrestha, Jennifer Pesklevits, Daqing Yang, Daniel L. Peters, Yonas B. Dibike
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2021
• Subjects: climatic controls; multiple linear regression; permafrost region; streamflow extremes; trend analysis; variable importance analysis; Hydraulic engineering; TC1-978; Water supply for domestic and industrial purposes; TD201-500; Arctic; Canada; permafrost
• Online Access: https://doi.org/10.3390/w13050626; https://doaj.org/article/8b9c18ca61b84c88baaf4d766b4bc031

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.