Differential frost heave model for patterned ground formation: Corroboration with observations along a North American arctic transect

Abstract

[1] Frost boils in the Arctic are a manifestation of patterned ground in the form of nonsorted circles. Active frost boils involve convection of water through the soil that can bring basic salts from depth to the surface. As such, active frost boils can mitigate acidification and thereby strongly influence the type of vegetation supported by Arctic soils. The presence or absence of active frost boils is thought to play a pivotal role in establishing the sharp demarcation between moist nonacidic tundra (MNT) and moist acidic tundra (MAT) in the Arctic. The focus of this paper is to corroborate the predictions of a mathematical model that relates observable patterned ground features to ecosystem parameters with observations at the field sites along the North American Arctic Transect (NAAT) established by the Biocomplexity of Patterned-Ground Ecosystems Project. Model predictions indicate that recurrent one-dimensional frost heave can become unstable and evolve into multidimensional differential frost heave (DFH). A laboratory frost heave simulation produced a 28-cm pattern in an active layer of 10 cm, which agrees with linear stability theory predictions. A finite element solution predicts threedimensional patterns with approximately 3-m spacing develop in a 1.0-m active layer with a surface n factor of 0.35, which agrees well with field observations from the NAAT. The lack of significant frost boil activity in the MAT is a result of suppression of DFH owing to denser surface vegetation characterized by low n factors. Prominent active frost boils are observed in the MNT at higher latitudes with more sparse vegetation characterized by higher n factors that promote DFH. However, at the northernmost field sites frost boils cannot be generated even though the n factors are relatively high owing to very rapid freezing conditions that mitigate DFH.

Stone circles: form and soil kinematics

“…The latter include the strong influence of the developing topography and textural differentiation on the transport of heat and moisture that fuel the development of sorted patterned ground. These studies of the stability of secondary frost heaving have much in common with recent models that focus on the formation of non-sorted patterned ground [44][45][46][47].…”

Advancing the use of minirhizotrons in wetlands

“…Sufficiently large topographic features, including hummock-hollow complexes (e.g., Johnson and Damman 1991), strings (i.e., aggregates of hummocks) and flarks (i.e., aggregates of hollows, Baird et al 2009) and permafrost features in arctic wetlands such as frost boils (Peterson and Krantz 2008), ice wedge polygons (Minke et al 2009), and thermokarst (Jorgenson et al 2001), can be sampled using a stratified random approach. Smaller topographic features, such as tussock production by some sedge species (e.g., Eriophorum vaginatum L., Chapin et al 1979), will likely be sufficiently captured with a completely random sampling design.…”

Classification of sorted patterned ground areas based on their environmental characteristics (Skagafjörður, Northern Iceland)

“…Washburn, 1956;Chambers, 1967;Ballantyne and Matthews, 1983;Jahn, 1985;Hallet et al, 1988;Krantz, 1990;Van Vliet-Lanoë, 1991;Kling, 1997Kling, , 1998Kessler et al, 2001;Kessler and Werner, 2003;Matsuoka et al, 2003;Peterson and Krantz, 2008), as well as on the environmental conditions associated with their occurrence (e.g. Matthews et al, 1998;Etzelmüller et al, 2001;Luoto and Hjort, 2004, 2005Hjort et al, 2007;Feuillet, 2011).…”