Linking micro-physical properties to macro features in ice sheets with geophysical techniques

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The flow of the Antarctic ice sheet is controlled by processes occurring at its surface, at its base, and by the spatial variation of rheological properties within the ice.The internal structure of the ice sheet represents an integrated memory of the interaction of these processes and properties, knowledge of which has key implications for unraveling its history and predicting its future behaviour.The proposed young research group engages in the detection of macro-scale internal layer architecture with electromagnetic and seismic reflection methods, and the understanding of physical properties on the micro-scale which cause the reflections.Laterally imaging the layer architecture yields complementary information to the direct evidence of physical properties otherwise solely provided by ice cores, which are however limited to single points.The frequency-dependent dielectric properties of firn and ice cores in the range of 100 kHz to 3 GHz are determined with a large coaxial cell.Seismic properties and the possibility to image these by surface experiments are investigated during field studies in the European Alps and in Antarctica.The combination with physical ice-core properties enables forward modeling of seismograms and identification of seismic reflector origins.Development of an inversion scheme yields the means to extract the micro-physical information inherent in electromagnetic and seismic data and to provide a distribution of physical properties in the ice column.