Hydrogeophysics in Areas with Seasonally Frozen Soils and Permafrost

Hydrology in the northern hemisphere is greatly affected by permafrost and seasonally frozen soils. Frozen ground near the surface will influence the distribution of melt-water and rain to run-off or infiltration. In areas of permafrost only the top layer of the ground, is active hydrologically in the summer season. Global warming can have large mechanical and hydrological effects in these areas. The average increase in temperature is for seasonally frozen soils expected to have lower impact than the frequency of freeze-thaw cycles, arrival time of snow compared to start of freezing temperatures etc. It is important to have methods for studying the dynamic hydrogeological processes under such conditions in order to improve our understanding of how processes are coupled and what the consequences of a changed climate may be on these processes. In this paper examples of different applications of geophysical methods in Norway, Svalbard and Russia will be presented. The examples relate to: Infiltration and solute transport in a partially frozen soil monitored with conventional lysimeter techniques and electrical resistivity, both surface arrays and tomography; Leakages below frozen dams using geometrical EM soundings and finally an example showing EM soundings of saline permafrost and abnormal polarization.