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Detection of runoff timing changes in pluvial, nival, and glacial rivers of western Canada
Author(s) -
Déry Stephen J.,
Stahl K.,
Moore R. D.,
Whitfield P. H.,
Menounos B.,
Burford Jason E.
Publication year - 2009
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2008wr006975
Subject(s) - streamflow , pluvial , surface runoff , glacial period , precipitation , climate change , environmental science , hydrology (agriculture) , physical geography , drainage basin , geology , climatology , geography , geomorphology , ecology , meteorology , geotechnical engineering , biology , oceanography , cartography
Changes in air temperature, precipitation, and, in some cases, glacial runoff affect the timing of river flow in watersheds of western Canada. We present a method to detect streamflow phase shifts in pluvial, nival, and glacial rivers. The Kendall‐Theil robust lines yield monotonic trends in normalized sequent 5‐day means of runoff in nine river basins of western Canada over the period 1960–2006. In comparison to trends in the timing of the date of annual peak flow and the center of volume, two other less robust metrics often used to infer streamflow timing changes, our approach reveals more detailed structure on the nature of these changes. For instance, our trend analyses reveal extension of the warm hydrological season in nival and glacial rivers of western Canada. This feature is marked by an earlier onset of the spring melt, decreases in summer streamflow, and a delay in the onset of enhanced autumn flows. Our method provides information on streamflow timing changes throughout the entire hydrological year, enhancing results from previous methods to assess climate change impacts on the hydrological cycle.