Thermal properties of Antarctic soils: wetting controls subsurface thermal state

Abstract

Mineral soils in the McMurdo Dry Valleys (MDV), Antarctica, are commonly considered to be dry, and therefore to be good insulators with low thermal diffusivity values (~0.2 mm2 s-1). However, field measurements of soil moisture profiles with depth, coupled with observations of rapid ground ice melt, suggest that the thermal characteristics of MDV soils, and thus their resistance to thaw, may be spatially variable and strongly controlled by soil moisture content. The thermal conductivity, heat capacity and thermal diffusivity of 17 MDV soils were measured over a range of soil moisture conditions from dry to saturated. We found that thermal diffusivity varied by a factor of eight for these soils, despite the fact that they consist of members of only two soil groups. The thermal diffusivity of the soils increased in all cases with increasing soil moisture content, suggesting that permafrost and ground ice thaw in mineral soils may generate a positive thawing feedback in which wet soils conduct additional heat to depth, enhancing rates of permafrost thaw and thermokarst formation.

Experimental Investigation of Thermo-Physical Properties of Soil Using Solarisation Technology

“…This finding agrees with the findings of (Levy and Schmidt, 2016;Miyajima et al, 2015;Usowicz et al 2016). The number of Plastic Films (PF) showed significant differences in D.…”

“…In contrast, other studies presented the contradictory result that tillage depth made no significant difference to ρb (Jabro et al, 2016;Karuma et al, 2014). Gnatowski (2009); Levy and Schmidt (2016) found that soil thermal diffusivity (D) is a fundamental property for studying the thermal process of soil. The results of their study indicate that D depends on moisture content because D is increased by increasing volumetric moisture content in soil.…”

“…However, Makarychev and Bolotov (2017) observed that soil thermal diffusivity (D) is decreased by increasing moisture content. Levy and Schmidt (2016) discovered that soil thermal diffusivity (D) significantly increased with increasing soil depth.…”

Hillslope water tracks in the High Arctic: Seasonal flow dynamics with changing water sources in preferential flow paths

“…Water tracks have been the object of study mostly in Alaska and Antarctica, yet they have been reported in other parts of the periglacial domain, albeit sometimes under other terminologies (Curasi, Loranty, & Natali, ; Nicholson, ; Woo & Xia, ). Their importance in the periglacial landscape extends beyond that of a simple hydrological pathway, as they play specific roles in heat transfer and active layer development (Gooseff et al, ; Hastings, Luchessa, Oechel, & Tenhunen, ; Levy & Schmidt, ; Paquette, Fortier, Mueller, Sarrazin, & Vincent, ; Paquette, Fortier, & Vincent, ), solute transport (Levy, Fountain, Gooseff, Welch, & Lyons, ), and nutrient and carbon cycling (Ball & Levy, ; Cheng et al, ; Mcnamara, Kane, Hobbie, & Kling, ; Oberbauer, Tenhunen, & Reynolds, ). They also play a role in the development of the landscape, acting as an immature drainage network (Mcnamara, Kane, & Hinzman, ), as moisture provider for slow mass wasting processes (Verpaelst, Fortier, Kanevskiy, Paquette, & Shur, ), or as indications of denudation by leaching of fine material (Paquette et al, ).…”

Decadal topographic change in the McMurdo Dry Valleys of Antarctica: Thermokarst subsidence, glacier thinning, and transfer of water storage from the cryosphere to the hydrosphere

“…Such positive melting feedbacks are also associated with permafrost degradation, where changes in drainage, the geometry of thermokarst ponds, channel stability, and active layer thermal properties can rapidly alter the distribution of soils, ice, and carbon (Jorgenson et al, 2006;Gooseff et al, 2011;Arp et al, 2015;Kanevskiy et al, 2016;Levy and Schmidt, 2016;Strauss et al, 2016). Hydrologically mediated melting of ground ice has led to thermokarst subsidence over broad study areas containing continuous permafrost.…”