Thermal characteristics and impact of climate change on mountain permafrost in Iceland

Abstract

[1] This study contains the first quantitative description of mountain permafrost in Iceland, obtained through analysis of four ground temperature time series from recently established shallow boreholes at high altitude ($900 m above sea level) in central and eastern Iceland. Permafrost is present at three of the four boreholes, where temperatures range from À2°to 0°C. During the data-logging period, 2004-2006, the thickness of the active layer at the individual sites varied between less than 2 m and more than 5 m, mainly owing to differences in near-surface ice content. The ground temperature profiles are nonlinear, with near-surface temperature perturbations considered to be related to a recent warming of the ground surface. At the one nonpermafrost site the insulating influence of winter snow cover is more pronounced. A one-dimensional heat-conduction model was calibrated using ground temperature measurements and driven by surface temperature time series. The model results reproduce the measured ground temperature pattern well. This simplified model, simulating the results of possible future climate scenarios, indicates that permafrost degradation will occur at these sites within decades, depending on climate scenarios chosen and subsurface ice content.

Modeling the impact of wintertime rain events on the thermal regime of permafrost

“…visible in the data published in Isaksen et al, 2002) and Iceland Farbrot et al, 2007). Furthermore, they are documented from Alaska, Arctic Canada (Grenfell and Putkonen, 2008) and the western-and easternmost parts of Siberia, e.g.…”

Modeling the temperature evolution of Svalbard permafrost during the 20th and 21st century

“…Etzelmüller et al, 2003;Ødegård et al, 1987) formed in sedimentary bedrock. Those are heavily shattered by frost weathering, and presumably an important source for coastal material transport and erosion (e.g.…”

“…The subsurface temperature distribution was simulated by numerically solving the transient 1-D heat equation for nonconstant coefficients (see also Farbrot et al, 2007 for more details): (Williams and Smith, 1989). As boundary conditions, we prescribe time series of GST and the geothermal heat flux Q geo = 65 mW m −2 at depth (Isaksen et al, 2000) (see also explanation on page 1885).…”

The origin of glacial alpine landscape in Tröllaskagi Peninsula (North Iceland)

“…Kellerer-Pirklbauer et al (2007) apply relative surface dating using a Schmidt-hammer. Farbrot et al (2007) study the headwall recession rates of these cirques. These studies point to a much older age for the formation and development of these rock glaciers than that proposed for the Nautárdalur rock glacier.…”

“…Farbrot et al (2007) studied the ground surface temperature in the Fremri-Grjótárdalur rock glacier and in its highest area, with mean temperatures (2005)(2006) between -0.5/-0.2ºC and -2.3ºC respectively. Wangensteen et al (2006) and Kellerer-Pirklbauer et al (2007) calculate approximate estimated surface velocities by streamline interpolations to calculate the age of these glaciers.…”