Climatic controls on mean and extreme streamflow changes across the permafrost region of Canada

Date

2021

Authors

Shrestha, Rajesh R.
Pesklevits, Jennifer
Yang, Daqing
Peters, Daniel L.
Dibike, Yonas B.

Journal Title

Journal ISSN

Volume Title

Publisher

Water

Abstract

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 (Qₘₑₐₙ), minimum flow (Qₘᵢₙ), maximum flow (Qₘₐₓ) and Qₘₐₓ 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) Qₘᵢₙ for 43% of stations as the most prominent trend, and a relatively smaller number of stations with significant Qₘₑₐₙ, Qₘₐₓ and Qₘₐₓ 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 Qₘₑₐₙ and seasonal precipitation, and a negative correlation between Qₘₑₐₙ and seasonal temperature. The basin-averaged streamflow, precipitation and temperature trends showed weak correlations that included a positive correlation between Qₘᵢₙ and October to March precipitation trends, and negative correlations of Qmax timing with October to March and April to September temperature trends. The MLR-based variable importance analysis revealed the dominant controls of precipitation on Qₘₑₐₙ and Qₘₐₓ, and temperature on Qₘᵢₙ. 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.

Description

We acknowledge Natural Resources Canada for permafrost database and Water Survey of Canada, Environment and Climate Canada, for hydrometric network basin polygons used in this study.

Keywords

climatic controls, multiple linear regression, permafrost region, streamflow extremes, trend analysis, variable importance analysis

Citation

Shrestha, R. R., Pesklevits, J. C., Yang, D., Peters, D. L., & Dibike, Y. (2021). Climatic controls on mean and extreme streamflow changes across the permafrost region of Canada. Water, 13(5), 626. https://doi.org/10.3390/w13050626