Interdecadal variability of streamflow in the Hudson Bay Lowlands watersheds driven by atmospheric circulation

Study region: Hudson Bay Lowlands watersheds, Ontario, Canada. Study Focus: The rivers in the Hudson Bay Lowlands are a major source of freshwater entering the Arctic Ocean and they also cause major floods. In recent decades, this region has been affected by major changes in hydroclimatic processes...

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Bibliographic Details
Published in:Journal of Hydrology: Regional Studies
Main Authors: Olivier Champagne, M. Altaf Arain, Shusen Wang, Martin Leduc, Hazen A.J. Russell
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier 2021
Subjects:
Hudson Bay Lowlands
Subarctic region
MESH
Streamflow
ERA5
Atmospheric circulation
Physical geography
GB3-5030
Geology
QE1-996.5
Arctic
Arctic Ocean
Canada
Hudson
Hudson Bay
Pacific
Climate change
permafrost
Subarctic
Online Access:https://doi.org/10.1016/j.ejrh.2021.100868
https://doaj.org/article/a4873681df874002a1d27a0600ba46f9
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Summary:Study region: Hudson Bay Lowlands watersheds, Ontario, Canada. Study Focus: The rivers in the Hudson Bay Lowlands are a major source of freshwater entering the Arctic Ocean and they also cause major floods. In recent decades, this region has been affected by major changes in hydroclimatic processes attributed to climate change and natural climate variability. In this study, we used ERA5 reanalysis data, hydrometric observations, and the hydrological model MESH, to investigate the impact of atmospheric circulation on the inter-decadal variability of streamflow between 1979 and 2018 in the Hudson Bay Lowlands. The natural climate variability was assessed using a weather regimes approach based on the discretization of daily geopotential height anomalies (Z500) from ERA5 reanalysis, as well as large scale oceanic and atmospheric variability modes. New hydrological insights: The results showed an anomalous convergence of atmospheric moisture flux between 1995–2008 that enhanced precipitation and increased streamflow in the western part of the region. This moisture convergence was likely driven by the combination of (i) low pressure anomalies in the East Coast of North America and (ii) low pressure anomalies in western regions of Canada, associated with the cold phase of the pacific decadal oscillation (PDO). Since 2009, streamflow remains high, likely due to more groundwater discharge associated with the degradation of permafrost.

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