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2.5D Inversion of Sea Ice Thickness from Helicopter EM Data
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, First European Airborne Electromagnetics Conference, Sep 2015, Volume 2015, p.1 - 5
Abstract
In this paper, we present a new 2D inversion approach to invert helicopter EM data for sea-ice thicknesses. The approach uses a 2.5D finite element frequency-domain solution of the Maxwell-Equations for the secondary field. Instead of inverting for resistivity values from which the location of the sea-ice/seawater boundary is derived, we directly invert for the location of the layer boundary, using fixed values for the resistivities of air, sea-ice and seawater.
Our approach was tested on a field data set from Antarctica acquired in 2005, using a frequency domain helicopter EM system. The data set covers a 500 m long profile, which contains flat sections that are approximately 1D, as well as pressure ridges with strong 2D character. The results of the 2D inversion are compared to earlier results from various 1D inversions and a sea-ice thickness data set obtained by drillings. The comparison shows that the 2D inversion gives a clear improvement for the areas with pressure ridges, while the 1D results appear to be less noisy for flat areas.