Investigating the effects of lateral water flow on the spatial patterns of thaw depth

Abstract

The effects of lateral water flow on the spatial distribution of the thaw depth in permafrost terrain have rarely been investigated with models. The GEOtop model, which solves the soil energy and water budgets in a coupled way and accounts for phase change, has been used to better understand how soil moisture spatial differences in the unfrozen upper part of the ground affect the thawing soil energy balance in idealized hillslope topography. Results show that, in terrains with thermal conductivity highly variable with soil moisture such as organic soils, wetter areas exhibit deeper thaw than drier areas. Conversely, if thermal conductivity depends less on soil moisture, as in mineral soils, the result is the opposite since the effect of the higher thermal capacity resulting from higher soil moisture prevails.