To better understand the changes in the hydrologic cycle caused by global warming in Antarctica, it is crucial to improve our understanding of the groundwater flow system, which has received less attention despite its significance. Both hydraulic and thermal properties of the active layer, through which groundwater can flow during thawing seasons, are essential to quantify the groundwater flow system. However, there has been insufficient information on the Antarctic active layer. The goal of this study was to estimate the hydraulic and thermal properties of Antarctic soils through laboratory column experiments and inverse modeling. The column experiments were conducted with sediments collected from two lakes in the Barton Peninsula, Antarctica. A sand column was also operated for comparison. Inverse modeling using HydroGeoSphere (HGS) combined with Parameter ESTimation (PEST) was performed with data collected from the column experiments, including permeameter tests, saturation -drain tests, and freeze -thaw tests. Hydraulic parameters (i.e., K s , theta s , S wr , alpha , beta, and S s ) and thermal diffusivity ( D ) of the soils were derived from water retention curves and temperature curves with depth, respectively. The hydraulic properties of the Antarctic soil samples, estimated through inverse modeling, were 1.6 x 10 - 5 -3.4 x 10 -4 cm s -1 for K s , 0.37 -0.42 for theta s , 6.62 x 10 - 3 -1.05 x 10 -2 for S wr , 0.53 -0.58 cm - 1 for alpha, 5.75 -7.96 for beta, and 5.11 x 10 - 5 -9.02 x 10 -5 cm - 1 for S s . The thermal diffusivities for the soils were estimated to be 0.65-4.64 cm 2 min -1 . The soil hydraulic and thermal properties reflected the physical and ecological characteristics of their lake environments. The results of this study can provide a basis for groundwater -surface water interaction in polar regions, which is governed by variably -saturated flow and freezethaw processes.

Permafrost and varying land surface properties greatly complicate modelling of the thermal response of Arctic soils to climate change. The forest-tundra transition near Nadym in west Siberia provides an excellent study area in which to examine the contrasting thermal properties of soils in a forested ecosystem without permafrost and peatlands with permafrost. We investigated the effects of forest shading, snow cover and variable organic soil horizons in three common ecosystems of the forest-tundra transition zone. Based on the year-round temperature profile data, the most informative annual parameters were: (1) the sum of positive average daily temperatures at depths of 10 and 20cm; (2) the maximum penetration depth of temperatures above 10 degrees C; and (3) the number of days with temperatures below 0 degrees C at a depth of 20cm. The insulative effect of snow cover in winter was at least twice that of the shading and cooling effect of vegetation in summer. In areas with shallow permafrost, the presence of a thick organic horizon, with an extremely low thermal diffusivity, creates a very steep temperature gradient that limits heat penetration to the top of the permafrost in summer. Copyright (c) 2015 John Wiley & Sons, Ltd.

Soil temperatures, water temperatures, and weather parameters were monitored at a variety of locations in the vicinity of King Sejong station, King George Island, Antarctica, during summer 2010-2011. Thermal characteristics of soil and water were analysed using time-series analyses, apparent thermal diffusivity (ATD), and active layer thickness. The temperatures of pond water and nearby seawater showed the distinctive diurnal variations and correlated strongly with solar radiation (r = 0.411-0.797). Soil temperature (0.1-0.3 m depth) also showed diurnal fluctuations that decreased with depth and were directly linked to air temperature (r = 0.513-0.783) rather than to solar radiation; correlation decreased with depth and the time lag in the response increased by 2-3 hours per 0.1 m of soil depth. Owing to the lack of snow cover, summertime soil temperature was not decoupled from air temperature. Estimated ATD was between 0.022 and 29.209 mm2/sec, showed temporal and spatial variations, and correlated strongly with soil moisture content. The maximum estimated active layer thickness in the study area was a 41-70 cm, which is consistent with values reported in the previous work.

Soil temperature regimes were studied in three ecosystems of the north of Western Siberia in the zone of isolated permafrost: the forest ecosystem with gleyic loamy sandy podzol (Stagnic Albic Podzol), the flat-topped peat mound ecosystem with humus-impregnated loamy sandy to light loamy peat cryozem (Histic Oxyaquic Turbic Cryosol (Arenic)), and the peat mound (palsa) ecosystem with oligotrophic destructive permafrost-affected peat soil (Cryic Histosol). Annual temperature measurements in the soil profiles demonstrated that these soils function under different temperature regimes: very cold permafrost regime and cold nonpermafrost regime. The following annual temperature characteristics proved to be informative for the studied soils: sums of above-zero temperatures at the depths of 10 and 20 cm, the maximum depth of penetration of temperatures above 10A degrees C, and the number of days with daily soil temperatures above (or below) 0A degrees C at the depth of 20 cm. On the studied territory, the insulating effect of the snow cover in winter was at least two times more pronounced than the insulating effect of the vegetation cover in summer. Cryogenic soils of the studied region are characterized by the high buffering towards changing climatic parameters. This is explained by the presence of the litter and peat horizons with a very low thermal diffusivity and by the presence of permafrost at a relatively shallow depth with temperature gradients preventing penetration of heat to the permafrost table.

Temperature profiles from the active layer have been analysed for 2 sites on the composed rockglacier Morenas Coloraclas. Cordon del Plata, Mendoza, Argentina, using monitoring data collected between 1989 and 2008 in order to characterize the impact of global warming in the cryolithozone of the Dry Andes at these latitudes (32 degrees-33 degrees S). A significant change in the active layer and suprapermafrost of this rockglacier of the Cordon del Plata is registered at the monitoring sites. The observed changes imply direct consequences for the cryogenic environment and the Andean creeping permafrost. The nose of the Morenas Coloradas rockglacier for example (Balcon I, 3560 m a.s.l.), already expresses inactivity; the permafrost table is found at great depth (7.5-9 m). Data collected at Balcon I and II allow to estimate the theoretical thermal diffusivity alpha at the active layer of Morenas Coloraclas. Thermal diffusivity may be decisive for the study of cryogenic dynamics at other altitudes and latitudes in the region where data are still scarce. Low alpha values (<0.2 x 10(-6)m(2)/s) correlate with occurrence of freezing and ice at low altitudes. While the glaciers are turning into small insignificant bodies in the high mountains, the periglacial level with creeping permafrost and linked with rockglaciers is expanding altitudinally, passing a transitional rooting area which is indirectly feeding the rockglaciers with their covered or dead ice. The ice of glacigenic origin contributes to the genesis of this type of permafrost. As the permafrost table is found at greater depths, the rockglaciers need to be monitored in order to define a balance between the upper periglacial level (in terms of altitude) with mountain continuous-quasi continuous permafrost and the lower periglacial level to where the lowest fronts of creeping permafrost are reaching. The variations of the cryogenic structure of the rockglaciers of the Cordon del Plata caused by warming processes, will have direct consequences for the volume of frozen sediments and therefore for the hydrology of the entire region, a fact that has to be taken into account for future socio-economic programs of the respective provincial governments. (C) 2008 Elsevier B.V. All rights reserved.

Borehole temperature measurements at the Dasan station were made by Baroo-Diver geothermal datalogger. During September 28, 2002 - August 12, 2003 three temperature data (at the depth of 0.25m, 0.5m, and 0.75m) were obtained by Environ Mon every thirty minutes. The thermal dynamics of active layer at the Dasan Korea Arctic Research Station, Svalbard (78 degrees 55.5'N, 11 degrees 56.0'E) is represented in the soil temperature which can be measured with high accuracy and high temporal resolution. Using the continuous data over a period of 318 days at the Dasan site, Svalbard, we deduce and quantify the processes which constitute the thermal dynamics. Conductive heat flow, migration of water vapor, and heat generation from phase transition are analyzed. Average thermal diffusivity indicates the range of thermal diffusivity 4x10(-7) similar to 6x10(-7)m(2)s(-1). The Dasna experiment is a good test of the geothermal method of climate reconstruction because the permafrost is a valuable recorder of climate change.