Reproducing Field‐Scale Active Layer Thaw in the Laboratory

Abstract

A method to simulate freeze–thaw and permafrost conditions on a large peat‐soil column, housed in a biome, was developed. The design limits ambient temperature interference and maintains one‐dimensional freezing and thawing. An air circulation system, in a cavity surrounding the active layer, allows manipulation of the lateral temperature boundary by actively maintaining an air temperature matching the average temperature of the soil column. Replicating realistic thermal boundary conditions enabled field‐scale rates of active‐layer thaw. Radial temperature gradients were small and temperature profiles mimicked those for similar field conditions. The design allows complete control of key hydrologic processes related to heat and water movement in permafrost terrains without scaling requirement; and presents a path forward for the large‐scale experimental study of frozen ground processes. Because subarctic ecosystems are very vulnerable to climate and anthropogenic disturbances, the ability to simulate perturbations to natural systems in the laboratory is particularly important.