Diagnosing changes in glacier hydrology from physical principles using a hydrological model with snow redistribution, sublimation, firnification and energy balance ablation algorithms

A comprehensive glacier hydrology model was developed within the Cold Regions Hydrological Modelling platform (CRHM) to include modules representing wind flow over complex terrain, blowing snow redistribution and sublimation by wind, snow redistribution by avalanches, solar irradiance to sloping surfaces, surface sub-limation, glacier mass balance and runoff, meltwater and streamflow routing. The physically based glacier hy-drology model created from these modules in CRHM was applied to simulate the hydrology of the instrumented, glacierized and rapidly deglaciating Peyto and Athabasca glacier research basins in the Canadian Rockies without calibration of parameters from streamflow. It was tested against observed albedo, point and aggregated glacier mass balance, and streamflow and found to successfully simulate surface albedo, snow redistribution, snow and glacier accumulation and ablation, mass balance and streamflow discharge, both when driven by in -situ observations and reanalysis forcing data. Long term modelling results indicate that the increases in discharge from the 1960s to the present are due to increased glacier ice melt contributions, despite declining precipitation and snow melt.

Automated summary

This article introduces a comprehensive glacier hydrology model developed within the Cold Regions Hydrological Modelling platform, which was applied to simulate the hydrology of glacier research basins in the Canadian Rockies. The model was successfully tested against observed data and found to accurately simulate various processes related to glacier hydrology. It also revealed that increased glacier ice melt contributions are the main reason for the increased discharge.