Mapping of permafrost surface using ground-penetrating radar at Kangerlussuaq Airport, western Greenland

Abstract

Abstract Kangerlussuaq Airport is located at 67°N and 51°W in the zone of continuous permafrost in western Greenland. Its proximity to the Greenlandic ice sheet results in a dry sub-arctic climate with a mean annual temperature of − 5.7 °C. The airport is built on a river terrace mostly consisting of fluvial deposits overlying fine-grained marine melt-water sediments and bedrock. A ground-penetrating radar (GPR) survey was performed to study the frozen surface beneath the airfield. The measurements were carried out in late July 2005 on the southern parking area in Kangerlussuaq Airport. Five years earlier, in autumn 2000, three test areas were painted white in order to reduce further development of depressions in the asphalt pavement. GPR profiles crossing the white areas show a distinct difference in depth to the permafrost surface under the painted areas compared to the natural black asphalt surface. GPR data also show a correlation between structures in the river terrace and depressions in the paved surface. The combination of large dark areas of asphalt pavement and perhaps a change in snow removal routines on the southern parking area have caused an increase in solar heating, a lowering of the permafrost surface and the formation of several depressions in the pavement of the southern parking area. The depressions can be clearly seen after rainfall. To calibrate the GPR survey, sediment samples from a borehole were analyzed with respect to water content, grain size and content of organic material. To find the exact depth of the permafrost a trench was dug down to the frozen surface.