Shallow soil moisture – ground thaw interactions and controls – Part 1: Spatiotemporal patterns and correlations over a subarctic landscape

摘要

Soil moisture and ground thaw state are both indicative of a hillslope'sability to transfer water. In cold regions, in particular, it is widelyknown that the depth of the active layer and wetness of surface soils areimportant for runoff generation, but the diversity of interactions betweenground thaw and surface soil moisture themselves has not been studied. Tofill this knowledge gap, detailed shallow soil moisture and thaw depthsurveys were conducted along systematic grids at the Baker Creek Basin,Northwest Territories. Multiple hillslopes were studied to determine how theinteractions differed along a spectrum of topological, typological andtopographic situations across the landscape. Overall results did not show asimple link between soil moisture and ground thaw as was expected. Instead,correlation was a function of wetness. The interaction between soil moistureand ground thaw was more dependent at wetter sites. This indicates thatinteractive soil moisture and thaw depth behaviour on hillslopes in coldregions changes with location and cannot necessarily be lumped together inhydrological models. To explore further why these differences arise, acompanion paper (Guan et al., 2010) will examine how the hydrological and energy fluxes influenced the patterns of moistureand thaw among the study sites.