Large-scale simulations of snow albedo masking by forests

Comparisons between climate models have found large differences in predictions for the albedo of forested regions with snow cover, leading to uncertainty in the strength of snow albedo feedbacks on climate change predicted by these models. To explore this uncertainty, three commonly used methods for calculating the albedo of vegetated surfaces are compared, taking observed snow and vegetation distributions as inputs. Surprisingly, all three methods produce similar results and compare reasonably well with observations over seasonally snow-covered regions of the Northern Hemisphere. It appears that some climate models use unrealistic parameter values, and snow albedo masking need not be as large a source of uncertainty as it is in current climate projections.