Investigating and revealing the nature and origin of electromagnetic reflections in polar ice by combination of numerical forward modeling techniques, ice core measurements, and radar field surveys
Professor Dr. Frank Wilhelms
Helmholtz-Zentrum für Polar- und Meeresforschung
The investigation of glaciers and ice sheets by means of ice penetrating radar has become one of the most commonly used geophysical techniques in glaciology. Many applications utilise internal reflection horizons, assuming that an individual reflector is isochronous. Although the different mechanisms causing reflections are in principle understood, open questions on their origin still remain. The project presented in this proposal has the goal to identify the constituting processes leading to internal electromagnetic reflections in cold ice at all depth levels, providing a comprehensive picture of reflection origin. Investigation of the nature of electromagnetic reflections will be performed by a combination of ice core records, airborne and surface-based ice penetrating radar surveys, and newly developed numerical forward modeling approaches. Determining the physical properties of an ice core by means of dielectric profiling forms the basis to simulate the propagation of an electromagnetic wave in cold ice with a finite-difference model. Direct comparison of modeled radargrams with measured radar data validates the model results, allowing sensitivity studies with altered ice core data and yielding insights into the significance of the different reflection processes. Physical interpretation of the modeling results will be achieved by analyses of the crystal fabric and pore volume of ice and answer the question which reflection horizons are isochrones.
Förderung von 2004 bis 2006