A strategy to represent impacts of subgrid-scale topography on snow evolution in the Canadian Land Surface Scheme

• Published in: Annals of Glaciology
• Main Authors: Waqar Younas, Rachel W. Hay, Matt K. MacDonald, Siraj ul Islam, Stephen J. Déry
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2017
• Subjects: accumulation; snow; snow/ice surface processes; surface mass budget; Meteorology. Climatology; QC851-999; British Columbia; Canada; Annals of Glaciology
• Online Access: https://doi.org/10.1017/aog.2017.29; https://doaj.org/article/bb091a0b51244f22825de1b095424665

This sensitivity study applies the offline Canadian Land Surface Scheme (CLASS) version 3.6 to simulate snowpack evolution in idealized topography using observations at Likely, British Columbia, Canada over 1 July 2008 to 30 June 2009. A strategy for a subgrid-scale snow (SSS) parameterization is developed to incorporate two key features: ten elevation bands at 100 m intervals to capture air temperature lapse rates, and five slope angles on four aspects to resolve solar radiation impacts on the evolution of snow depth and SWE. Simulations reveal strong elevational dependencies of snow depth and SWE when adjusting temperatures using a moist adiabatic lapse rate with elevation, with 26% peak SWE differences between that at the average elevation versus the mean of the remainder of the elevation bands. Differences in peak SWE on north- and south-facing slopes increase from 3.0 mm at 10° slope to 17.9 mm at 50° slope. When applied to elevation, slope and aspect combinations derived from a high-resolution digital elevation model, elevation dominates the control of peak SWE values. Inclusion of the range of SSS effects into a regional climate model will improve snowpack and hydrological simulations of western North America's snow-dominated, mountainous watersheds.