Modeled surface air temperature response to snow depth variability

摘要

Previous literature has established a relationship between snow cover and climate on large and small scales, but has focused on the influence of the presence versus absence of snow cover. A small body of literature indicates that snow depth can also influence properties of the atmosphere, through its ability to insulate the land surface. In this study, we investigate the local surface air temperature response to perturbations in snow water equivalent over the course of a single season, using the regional climate model RegCM3. Snow depth is specified as a percentage of the climatological snow water equivalent averaged over a small domain within a larger 3000 x 3000 km model domain, both centered at Minneapolis—St. Paul, Minnesota, United States (44.87°N, 93.22°W). In response to a specified increase in snow water equivalent corresponding to a shift from shallow (31 cm) snow, we find a seasonally averaged reduction in surface air temperatures that is on the order of 1℃, with smaller and larger responses observed within a season. Coincident with this change, we find reduced upward sensible heat flux at the surface. Both results are consistent with those of previous studies when differences in methodology are accounted for. The response achieved here extends vertically and horizontally beyond the forcing domain, suggesting the potential for the influence of snow depth on large-scale features of climate.