Johan Ludvig Sollid

Permafrost in Svalbard: a review of research history, climatic background and engineering challenges

This paper reviews permafrost in High Arctic Svalbard, including past and current research, climatic background, how permafrost is affected by climatic change, typical permafrost landforms and how changes in Svalbard permafrost may impact natural and human systems. Information on active layer dynamics, permafrost and ground ice characteristics and selected periglacial features is summarized from the recent literature and from unpublished data by the authors. Permafrost thickness ranges from less than 100 m near the coasts to more than 500 m in the highlands. Ground ice is present as rock glaciers, as ice-cored moraines, buried glacial ice, and in pingos and ice wedges in major valleys. Engineering problems of thaw-settlement and frost-heave are described, and the implications for road design and construction in Svalbard permafrost areas are discussed.

Deglaciation of Finnmark, North Norway

Altitude relationships between shore forms and their sea levels are investigated. Raised shore lines are measured in a large number of localities. Equidistant shore-line diagrams are constructed and used for relative dating purposes. Late Glacial shore lines older than the Main line (Younger Dryas time) seem to have larger gradients than assumed in previous studies. Selected glacial landforms are mapped and interpreted. In the investigated area, the ice reached beyond the coast of Finnmark during the last Glacial maximum. Distinct end moraines mark numerous halts during the subsequent ice recession. Margins of sub-stages are traced, and local glaciers and accumulation centres are located. The Main sub-stage moraines are best developed regionally. Important aspects of deglaciation patterns and ice-directed drainage are described. Streamlined forms are analysed in relation to topography, and axes of fossil inland dunes measured.

Neoglaciation in South Norway using lichenometric methods

The neoglacial history of South Norway is illuminated through a lichenometric study of 14 ice-marginal zones of glaciers situated along a right angled line running north-south and west-east to cover a vast area. Maps of the marginal zones two lichen growth curves, the moraine dates and a frequency diagram are presented on a plate, PI. 1. If there are reference points to check the growth curves, lichenometry is found to be reliable to fix the time of deglaciation of the moraine ridges within a period of about three hundred years. A total of 101 moraine ridges were dated and the results show that their deglaciation time is concentrated around 1930, 1905, 1900, 1880, 1860, 1840, 1820 and 1800. The deglaciation of the outermost moraines is concentrated within the period 1780–1820.

Mountain permafrost distribution in Dovrefjell and Jotunheimen, southern Norway, based on BTS and DC resistivity tomography data

The influence of climate and topography on the distribution of permafrost within the Dovrefjell and Jotunheimen areas, southern Norway, is analysed. A dataset of 972 BTS (bottom temperature of winter snow) measurements was analysed in relation to altitude, potential direct incoming radiation, aspect, snow depth, curvature and slope. To confirm and characterise permafrost-transition zones indicated from the BTS measurements, miniature temperature data-loggers, borehole temperatures, one-dimensional DC resistivity soundings and two-dimensional DC resistivity tomography were used. In addition, small-scale variance analyses upon the BTS values were performed using spatial-statistical methods. Results confirm that BTS values are highly correlated with altitude. Based on analysis of BTS data, the lower limit of possible permafrost is 1490 m a.s.l. on Dovrefjell and 1460 m a.s.l. in Jotunheimen. The relation between altitude and BTS suggests that the climate conditions on Dovrefjell and in Jotunheimen are similar with respect to permafrost distribution. Potential direct incoming radiation (PR) has a minor influence on BTS. A significant correlation between both surface moisture and surface type conditions in summer and BTS measurements were found. The results from Jotunheimen suggest that 20-45% of the variance in BTS results that are not explained by altitude are explained by small-scale spatial variance within a 20-30 m range. The results from the BTS measurements and the two-dimensional DC resistivity tomography were highly consistent.

Distribution of Glacial Landforms in Southern Norway in Relation to the Thermal Regime of the Last Continental Ice Sheet

ABSTRACTThe zonation of moraines and meltwater landforms in southern Norway indicates that the ice sheet was cold-based during the deglaciation of the central areas. Flutes, drumlins, Rogen moraines and end moraines in these central areas most probably predate the late Weichselian. There is also a vertical zonation of landforms which indicate that the highest areas became cold-based at an early stage during the last glaciation. These higher areas are characterized by blockfields and other weathering phenomena, and no traces of glaciation except meltwater channels and erratic boulders. Later the cold-based zone of the glacier expanded both downwards to lower parts of the terrain and outwards to areas further away from the culmination zone. In these areas the glacier stayed cold-based throughout the deglaciation period. Flutes, drumlins and end moraines were fossilized beneath cold-based ice, while Rogen moraines were formed by ice movement in warm-based patches with trapped water beneath a glacier that was...

Aspects and concepts on the geomorphological significance of Holocene permafrost in southern Norway

This review paper aims at discussing aspects and concepts of the significance of the spatial and temporal distribution of permafrost on glacial and gravitational processes in southern Norway. The study first reviews the distribution of mountain permafrost in southern Norway in comparison with high-relief alpine areas like the Alps, and then discusses the influence of permafrost on gravitational and glacial–geomorphological processes. The basis for the paper is a regional-scale distribution model of mountain permafrost in southern Norway, which is analysed in relation to topographic variations within the same area. The model allows a crude extrapolation to past and future permafrost distribution, which is discussed in relation to geomorphic processes.

Ground surface-temperature reconstruction based on data from a deep borehole in permafrost at Janssonhaugen, Svalbard

Abstract Analyses of the geothermal gradient in permafrost areas constitute a key signal of the ground-surface temperature history. Permafrost temperatures in selected areas are particularly well suited to reconstructing past surface-temperature changes, mainly because there is no thermal disturbance due to circulating groundwater. One year of temperature data from an instrumented 102 m deep borehole in permafrost on Janssonhaugen, Svalbard, is presented. Ground thermal properties are calculated. The average value for the thermal conductivity is 1.85 ±0.05 W m–1 K–1 , and the average value for the thermal diffusivity is 1.1m2 s–1, which gives a phase speed for the annual wave of 5.65 × KT2 m d–1. The depth of zero annual amplitude is 18 m The permafrost thickness is estimated as approximately 220 m. Analysis of the temperatures reveals an increasing temperature gradient with depth. Using a heat-conduction inversion model, a palaeoclimatic reconstruction is presented, showing a warming of the surface temperature over the last 60–80 years. The temperature profile represents a regional signal on Svalbard, which shows an inflection associated with near-surface warming of 1.5 ± 0.5°C in the 20th century.

Mapping and modelling the occurrence and distribution of mountain permafrost

This paper reviews the principles related to the mapping and modelling of the occurrence and distribution of mountain permafrost. It gives a state-of-the art report about this topic and defines future research needs.

Glacier characteristics and sediment transfer system of Longyearbreen and Larsbreen, western Spitsbergen

Two small high-Arctic glaciers (Longyearbreen and Larsbreen) on Svalbard (78°N 15°E) were studied with respect to glaciological and hydrological characteristics. Fieldwork during the melting season of 1993 and 1994 was coupled with digital map analysis based on high-resolution digital elevation models (DEM) to reveal the dynamics and temperature regime of small glaciers in a high-Arctic environment, and its relationship to the material transport and sedimentation of these glaciers. The study showed Longyearbreen and Larsbreen to be low activity glaciers, cold-based with temperate patches, and thus having a low potential of basal erosion. The transport of ions and suspended solids in the glacial meltwater implies storage of material in and around the glacier which comes into contact with the meltwater. The study suggests that small Arctic glaciers couple the slope system with the fluvial system and therefore build a highly effective denudation system. Small polythermal glaciers are therefore important in understanding Pleistocene and Holocene landform development in cold regions.

Deep permafrost boreholes in western Svalbard, northern Sweden and southern Norway

The first deep permafrost boreholes (>10 m) ever drilled in Scandinavia for climatic studies constitute part of a transect of deep mountain permafrost boreholes through the mountains of Europe established under the EU PACE (Permafrost and Climate in Europe) Project. In Scandinavia, PACE boreholes are located at Juvvasshøe, southern Norway, Tarfalaryggen in northern Sweden, and northernmost in the transect at Janssonhaugen, western Svalbard. This paper outlines the aims and objectives of the PACE programme, and describes in detail the Svalbard and Scandinavian permafrost boreholes.