IAHS-AISH Scientific Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Impact of climate change on the contribution of glaciers to the Upper Yukon River 

Cheick Doumbia and Alain N. Rousseau
Cheick Doumbia and Alain N. Rousseau
  • Institut National de la Recherche Scientifique, Eau Terre Environnement, Canada (cheick.doumbia@inrs.ca)

In the Upper Yukon Watershed (UYW, 20,000 km2), seasonal melt from glaciers contribute significantly to annual runoff and operation of the Whitehorse power plant. This study aims to analyze the impact of climate change on the contribution of glaciers, which covers 5% of the UYW, to the annual runoff using hydrological modelling, GRACE data and machine learning algorithms.

The spatial resolution of GRACE data remains too low to discriminate changes in glacier mass signal at the scale of the UYW. Thus, here we applied a spatial concentration function approach to build high resolution monthly time-series of glaciers mass changes over the UYW. To estimate glaciers mass changes, we decomposed four GRACE TWS solutions with different processing assumptions using monthly data from LSM GLDAS v2.1 (Rodell et al., 2004) and WGHM v2.2d (Müller Schmied et al., 2020). Spatial concentration functions were derived from two heterogeneous a priori of different resolutions and sources (Hugonnet et al., 2021; Larsen et al., 2015) and the leakage was subtracted by using glaciers over the Gulf Of Alaska (GOA). To analyze the accuracy of our assessments, we compared the trends resulting from the spatial concentration functions and the constrained forward approach (Doumbia et al., 2020) over the GOA and the Saint-Elias Mountains. To extend/reconstruct glacier mass change up to GRACE-FO (i.e. 2003-2020), we used the Automated Machine Learning (AML) H2O-AutoML (LeDell and Poirier, 2020). Then, glacier mass anomalies were used to calibrate the hybrid (i.e., degree-day/thermal energy balance) glacier melt model of HYDROTEL over UYW.

For the period of 2003 to 2016, the trends in glaciers mass losses over the GOA and Saint-Elias Mountains varied from 41.61 to 53.43Gt/yr and 19.31 to 28.88Gt/yr, respectively. Our results compared well with the glaciers mass losses reported in other studies. The AML algorithms performed well with NSE values varying from 0.75 to 0.99; correlation coefficients from 0.93 to 0.99; P-bias from -2.4 to 4.8 and NMRSE from 0.8 to 49.6. The use of the glacier mass changes, in addition to stream flows, improved the calibration of HYDROTEL. 

How to cite: Doumbia, C. and N. Rousseau, A.: Impact of climate change on the contribution of glaciers to the Upper Yukon River , IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-449, https://doi.org/10.5194/iahs2022-449, 2022.