Preprints
https://doi.org/10.5194/hess-2021-349
https://doi.org/10.5194/hess-2021-349

  27 Jul 2021

27 Jul 2021

Review status: this preprint is currently under review for the journal HESS.

Recent hydrological response of glaciers in the Canadian Rockies to changing climate and glacier configuration

Dhiraj Pradhananga1,2,3 and John W. Pomeroy1 Dhiraj Pradhananga and John W. Pomeroy
  • 1Centre for Hydrology, University of Saskatchewan, Canmore, 1151 Sidney Street, Alberta, Canada T1W 3G1
  • 2Department of Meteorology, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu, Nepal
  • 3The Small Earth Nepal, P.O. Box 20533, Kathmandu, Nepal

Abstract. Mountain snow and ice greatly influence the hydrological cycle of alpine regions by regulating both the quantity and seasonal variations of water availability downstream. This study considers the combined impacts of climate and glaciers changes due to recession on the hydrology and water balance of two high-elevation basins in the Canadian Rockies. A distributed, physically based, uncalibrated glacier hydrology model developed in the Cold Regions Hydrological Modelling platform (CRHM) was used to simulate the glacier mass balance and basin hydrology of Peyto and Athabasca Glacier basins in Alberta. Bias-corrected reanalysis data were used to drive the model. The model calculates the water balance of a glacierized basin, influenced by the surface energy and mass balance, and considering redistribution of snow by wind and avalanches. It was set up using hydrological response units based on elevation bands, surface slope and aspect, as well as changing land cover. Aerial photos, satellite images and Digital Elevation Models (DEM) were assimilated to represent the changing configurations of glacier area and the exposure of ice and firn. Observations of glacier mass balance, snow and glacier ice surface elevation changes at glacier and alpine tundra meteorological stations and streamflow discharge at the glacier outlets were used to evaluate the model performance. Model results indicated that both basins have undergone continuous glacier loss over the last three to five decades, leading to a 6–31 % reduction in glacierized area, a 78–109 % increase in ice exposure, and changes to the elevation and slope of the glacier surfaces. Diurnal temperature ranges are increasing, mainly due to increasing summer maximum daily temperatures. Annual precipitation is not changing much, but rainfall ratios are increasing. Basin hydrology was simulated over two periods, 1965–1975 and 2008–2018, using observed glacier configurations. The results show that changes in both climate and glacier configuration caused changes in melt rates and runoff, and a shift of peak flows from August to July. Glacier melt contributions increased from 27–61 % to 43–59 % of annual discharges. Recent discharges were 3–19 % higher than in the 1960s and 1970s. The results suggest that increased exposure of glacier ice and lower surface elevation due to glacier thinning were less influential in increasing streamflow than climate warming. Streamflow from these glaciers continues to increase.

Dhiraj Pradhananga and John W. Pomeroy

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on hess-2021-349', Anonymous Referee #1, 21 Aug 2021
  • RC2: 'Comment on hess-2021-349', Eleanor Bash, 28 Sep 2021

Dhiraj Pradhananga and John W. Pomeroy

Data sets

Hydrometeorological, glaciological and geospatial research data from the Peyto Glacier Research Basin in the Canadian Rockies Pradhananga, D., Pomeroy, J., Aubry-Wake, C., Munro, D., Shea, J., Demuth, M., Kirat, N., Menounos, B., Mukherjee, K. https://doi.org/10.5194/essd-13-2875-2021

Hydrometeorological, glaciological and geospatial research data from the Peyto Glacier Research Basin in the Canadian Rockies Pradhananga, D., Pomeroy, J., Aubry-Wake, C., Munro, D., Shea, J., Demuth, M., Kirat, N., Menounos, B., Mukherjee, K. https://doi.org/10.20383/101.0259

Dhiraj Pradhananga and John W. Pomeroy

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Short summary
This study considers the combined impacts of climate and glaciers changes due to recession on the hydrology and water balance of two high-elevation glaciers. Peyto and Athabasca Glacier basins in the Canadian Rockies have undergone continuous glacier loss over the last three to five decades, leading to increase in ice exposure, and changes to the elevation and slope of the glacier surfaces. Streamflow from these glaciers continues to increase more due to climate warming than glacier recession.