Changes in Snow Mass Balance in the Canadian Rocky Mountains Caused by CO2 Rise: Regional Atmosphere Model Results

Abstract

This study investigates snow mass balance in the Canadian Rockies under a relatively conservative Intergovernmental Panel on Climate Change emission scenario for the twenty-first century through the use of regional atmosphere modelling. We dynamically downscale results from five 10-year subsets of general circulation model integrations to 6?km resolution to produce a physically consistent representation of the atmosphere at high elevations. Regional model results make evident greater warming with increasing elevation at low to mid-levels of the atmosphere, and a simple thermodynamic explanation of this process is presented. Simulated increases in atmospheric water vapour result in increases in cloud cover and precipitation at high elevations, which temporarily offset the effects of rising temperatures, but by 2100 all model elevations experience reductions in snow mass balance. A simple energy balance model produces reasonable estimates of changes in the elevation of equilibrium net snow accumulation, with increases between 185 and 197?m under an approximate 1.5°C rise in surface temperatures by 2100.     

Finite-element method in modeling geologic transport processes

Deterministic mathematical modeling of complex geologic transport processes may require the use of odd boundary shapes, time dependency, and two or three dimensions. Under these circumstances the governing transport equations must be solved by numerical methods. For a number of transport phenomena a general form of the convective-dispersion equation can be employed. The solution of this equation for complicated problems can be solved readily by the finite-element method. Using quadrilateral isoparametric elements or triangular elements and a computational algorithm based on Galerkin's procedure, solutions to unsteady heat flux from a dike and seawater intrusion in an aquifer have been obtained. These examples illustrate that the finite-element numerical procedure is well suited for solving boundary-value problems resulting from modeling of complex physical phenomena.