Joint assembly AGU-GAC-MAC-CGU
Year of publication:
This paper focuses on the validation of snow characteristics in ERA-40/ERA-Interim driven Canadian Regional Climate Model simulation, and assessment of snow albedo feedback. Validation is performed by comparing simulated data against available observations from CMC, MODIS and ISCCP, results suggest that the model is able to capture the main spatial distribution patterns of snow mass and snow depth, with some overestimation in the Canadian high Arctic. However, it must be noted that there are large uncertainties in observation for these regions. The snow-albedo feedback in this simulation spanning the 1981-2010 period is assessed in the context of seasonal cycle, as the amount of additional net shortwave radiation at the top of the atmosphere as surface albedo decreases in association with a 1°C change in surface temperature during the April-May transition period. Following Qu and Hall (2006), this is expressed as the product of the variation in planetary albedo with surface albedo and change in surface albedo for 1°C change in surface air temperature during the season, which in turn is determined by the strength of the snow cover and snowpack metamorphosis feedback loops. Analysis of the latter term suggests that for CRCM simulation, the snow cover feedback loop is more dominant compared to the snow metamorphosis feedback loop. The snow-albedo feedback in the transient climate change simulations of the fifth generation of the Canadian Regional climate model, driven by two CMIP5 GCMs, for RCP scenarios 4.5 and 8.5, is also studied and snow cover feedback loop appear to be the prominent one, though differences in feedback strength is noted among the four CRCM simulations driven by the two GCMs and the two RCP scenarios.