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Northern Rocky Mountain streamflow records: Global warming trends, human impacts or natural variability?
Author(s) -
St. Jacques JeannineMarie,
Sauchyn David J.,
Zhao Yang
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl042045
Subject(s) - streamflow , climatology , environmental science , pacific decadal oscillation , dryness , proxy (statistics) , climate change , el niño southern oscillation , hydrology (agriculture) , geology , geography , drainage basin , oceanography , medicine , cartography , surgery , geotechnical engineering , machine learning , computer science
The ∼60 year Pacific Decadal Oscillation (PDO) is a major factor controlling streamflow in the northern Rocky Mountains, causing dryness during its positive phase, and wetness during its negative phase. If the PDO’s influence is not incorporated into a trend analysis of streamflows, it can produce detected declines that are actually artifacts of this low‐frequency variability. Further difficulties arise from the short length and discontinuity of most gauge records, human impacts, and residual autocorrelation. We analyze southern Alberta and environs instrumental streamflow data, using void‐filled datasets from unregulated and regulated gauges and naturalized records, and Generalized Least Squares regression to explicitly model the impacts of the PDO and other climate oscillations. We conclude that streamflows are declining at most gauges due to hydroclimatic changes (probably from global warming) and severe human impacts, which are of the same order of magnitude as the hydroclimate changes, if not greater.