Seasonal snowpack characteristics influence soil temperature and water content at multiple scales in interior western U.S. mountain ecosystems

摘要

Mountain snowpacks directly and indirectly influence soil temperature (T_(soil)) and soil water content (θ). Vegetation, soil organisms, and associated biogeochemical processes certainly respond to snowpack-related variability in the soil biophysical environment, but there is currently a poor understanding of how snow-soil interactions vary in time and across the mountain landscape. Using data from a network of automated snowpack monitoring stations in the interior western U.S., we quantified seasonal and landscape patterns in T_(soil) and θ, and their dependence on snowpack characteristics over an eleven year period. Elevation gradients in T_(soil) were absent beneath winter snowpacks, despite large gradients in air temperature (T_(air)). Winter T_(soil) was warmer and less variable than T_(air), but interannual and across-site variations in T_(soil) were likely large enough to impact biogeochemical processes. Winter θ varied between years and across sites, but during a given winter at a site it changed little between the start of snowpack accumulation and the initiation of spring snowmelt. Winter T_(soil) and θ were both higher when early winter snow accumulation was greater. Summer θ was lower when summer T_(air) was high. Depending on the site and the year examined, summer θ was higher when there was greater summer precipitation, a larger snowpack, later snowpack melt, or a combination of these factors. We found that snowpack-related variability in the soil environment was of sufficient magnitude to influence biogeochemical processes in snow-dominated ecosystems.