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TitleGlacier melt and potential impacts on water resources in the Canadian Rocky Mountains
AuthorCastellazzi, P; Burgess, D; Rivera, A; Huang, J; Longuevergne, L; Demuth, M
Alt SeriesNatural Resources Canada, Contribution Series 20180276
Lang.English
Mediapaper
SubjectsWater resources
ProgramNational Aquifer Evaluation & Accounting, Groundwater Geoscience
Abstract(unpublished)
Although global warming and glaciers melt are well studied, little is known about the related changes into downstream water flow systems. This study aims to quantify the glacier melt in the Canadian Rocky Mountains and Southern Interior Ranges to improve our understanding of its impacts over downstream flow systems. In this perspective, we present in-situ observations of glaciers, geodetic measurements of glacier melt, a glaciers mass balance model, in-situ river base-flow analysis, and time-variable gravity data from GRACE satellites and its related decomposition data, e.g., global surface hydrology and post-glacial rebound models.
The budget-based glacier mass loss estimates the ice loss at 44 Gt for the period 2002-2015, corresponding to an average of 3.1 Gt/yr. The total error is calculated through comparison with in-situ data, geodetic ice thickness change measurements, and independent model results. Uncertainty is estimated at +/- 2.3 Gt/yr, i.e., the model-derived ice mass loss estimation falls in the range [-0.8 -5.4] Gt/yr. In contrast, the GRACE TWS trend signal, after removal of all contributors other than glacier ice and groundwater, falls within the range [-0.4 +2] Gt/yr. These results suggest that increased groundwater storage partially compensates for the decreased glacier mass, at a rate of [+0.4 +7.2] Gt/yr. To explore this hypothesis, observations from other authors, groundwater storage change estimates from a global groundwater model, and river base-flow analysis are used and co-interpreted. While a groundwater storage model suggests that glaciers would be the main contribution to a potential storage increase, in-situ river flow analysis suggests a spatially heterogeneous base-flow response depending on the watershed and its groundwater residence time.
This article raises questions on discordant observations from multi-source datasets and explores explanatory scenarios. This inter-disciplinary approach triggers further investigation regarding the fate of glacier melt water, and encourage further work using data from the GRACE-FO mission.
Summary(Plain Language Summary, not published)
Although global warming and glaciers melt are well studied, little is known about the related changes into downstream water flow systems. This study aims to quantify the glacier melt in the Canadian Rocky Mountains and Southern Interior Ranges to improve our understanding of its impacts over downstream flow systems. We present observations of glaciers, geodetic measurements of glacier melt, a glaciers mass balance model, river base-flow analysis, and time-variable gravity data from GRACE satellites and its related decomposition data, e.g., global surface hydrology and post-glacial rebound models. Glacier mass loss estimates account for ice loss at 44 Giga-tons (Gt) for the period 2002-2015, corresponding to an average of 3.1 Gt/yr, while the GRACE Total Water Storage trend signal falls within the range [-0.4 +2] Gt/yr. We interpreted this discrepancy as related to water transfers between glaciers and groundwater storage, suggesting that increased groundwater storage partially compensates for the decreased glacier mass, at a rate of [+0.4 +7.2] Gt/yr.
GEOSCAN ID313073