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

Abstract

Mountain snowpacks directly and indirectly influence soil temperature (Tsoil) 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 Tsoil and θ, and their dependence on snowpack characteristics over an eleven year period. Elevation gradients in Tsoil were absent beneath winter snowpacks, despite large gradients in air temperature (T air). Winter Tsoil was warmer and less variable than Tair, but interannual and across-site variations in Tsoil 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 Tsoil and θ were both higher when early winter snow accumulation was greater. Summer θ was lower when summer Tair 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. © 2014. American Geophysical Union. All Rights Reserved.