Dynamic Equilibrium Modeling of Snow and Inland Glaciers under the Evolving Climate in Wyoming

Abstract

Most snow hydrology models do not include the long-term effects of interannual snow storage such as glaciers because glacier dynamics have a longer timescale than river flow and seasonal snowmelt. Interannual snow and ice, including inland glaciers, should be treated as systems in dynamic equilibrium that remain constant under a static climate condition. The model introduced here considers the movement of snow/ice from high-elevation areas to valleys by means of wind redistribution, avalanches, and glaciation. The relocated snow and ice may melt faster because of the higher temperatures of low-elevation areas. The reference temperature increase was modeled as a proportion to the snow and ice mass in a computational cell. The proportional coefficient can describe the equilibrating factor of the glacier system. This study discusses the physically based modeling of such a dynamic equilibrium snow system for long-term snow simulations at a regional scale. The developed regional snow (RegSnow) model was coupled with the weather research and forecasting (WRF) model to compute the snow surface-energy fluxes. According to the model implemented for Wyoming in the United States, approximately 82.2% of interannual snow and ice storage may disappear by the end of this century based on the temperature increase projected by general circulation models (GCMs) under the representative concentration pathway (RCP) 4.5 emission scenario.