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Aquifer Responses to El Niño–Southern Oscillation, Southwest British Columbia
Author(s) -
Fleming Sean W.,
Quilty Edward J.
Publication year - 2006
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.2006.00187.x
Subject(s) - hydrometeorology , precipitation , streamflow , climatology , environmental science , el niño southern oscillation , aquifer , annual cycle , forcing (mathematics) , water cycle , magnitude (astronomy) , hydrology (agriculture) , groundwater , atmospheric sciences , geology , meteorology , geography , drainage basin , ecology , physics , cartography , geotechnical engineering , astronomy , biology
Abstract We used climatological composite analysis to investigate El Niño–Southern Oscillation (ENSO) signals in long‐term shallow ground water level observations from four wells in the lower Fraser Valley of British Columbia. Significance of differences between warm‐phase, cold‐phase, and neutral climate states was assessed with a Monte Carlo bootstrap technique. We also considered time series of local precipitation and streamflow for comparison. Composite annual hyetographs suggest that ENSO precipitation impacts are largely limited to winter and spring, with higher and lower rainfall occurring, respectively, under cold‐phase and warm‐phase episodes. This is consistent with prior work in the region and is found to be directly reflected in both streamflow and ground water level data. The mean magnitude of ENSO terrestrial hydrologic anomalies can be up to ∼50% of the average seasonal cycle amplitude. ENSO does not appear to systematically affect annual hydrometeorological cycle timing in this study area. However, relative to the surface hydrologic systems considered, aquifers are observed to retain a stronger memory of seasonal ENSO‐related precipitation anomalies, with changes potentially extending through the following summer, presumably reflecting storage effects. Most responses appear to be somewhat nonlinear.