Electromagnetic Principles for In Situ Ice Thickness Determination - Field Experiments and Development of New Methods for Interpretation

During the spring of 2014 fieldwork in three different locations on Svalbard was conducted in order to investigate the application of electromagnetic methods on sea ice and ice ridges. Two validation grids, one transect across Sveasundet, a walkabout, an ice ridge and 8 ice cores have been measured. Results show an average thickness less than one meter for all but the ice ridge, which was 1,9 meters at the thickest point. Simulation based calculation of the relationship between the measured apparent conductivity and the level ice thickness, using MarcoAir, show great accuracy and potential. The sea ice conductivity profile is shown to have great effect on the calculated thickness, and this becomes more and more apparent as the thickness of the ice increases. This effect is shown, by using a simple quasi-2D model of an ice ridge, to hold for ice ridges. Investigation into the potential methods of estimating internal structures of ice ridges show that there are great potential in using simulation and modelling in combination with inversion, in order to assess these properties.