Investigating the origin of shallow electromagnetic reflections in cold ice by finite-difference forward modeling
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.Although many different applications utilise internal reflection horizons, assuming that an individual reflector is isochronous, open questions...
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ftawi:oai:epic.awi.de:6103 2023-09-05T13:13:04+02:00 Investigating the origin of shallow electromagnetic reflections in cold ice by finite-difference forward modeling Eisen, Olaf Wilhelms, Frank Nixdorf, Uwe Miller, Heinrich 2003 https://epic.awi.de/id/eprint/6103/ https://hdl.handle.net/10013/epic.16653 unknown Eisen, O. orcid:0000-0002-6380-962X , Wilhelms, F. orcid:0000-0001-7688-3135 , Nixdorf, U. and Miller, H. (2003) Investigating the origin of shallow electromagnetic reflections in cold ice by finite-difference forward modeling , EGS 2003. . hdl:10013/epic.16653 EPIC3EGS 2003. Conference notRev 2003 ftawi 2023-08-22T19:45:53Z 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.Although many different applications utilise internal reflection horizons, assuming that an individual reflector is isochronous, open questions concerningthe different reflection mechanisms remain.We demonstrate successful simulation of ice penetrating radar traces in polar ice by numerical finite-difference time-domain forward modeling.Based on a combined analyses of ice core records, radar surveys, and numerical sensitivity studies, we are able to provide better insights into the origin ofelectromagnetic reflections.By means of high resolution dielectric profiling (DEP) the physical properties of the upper 100 m of an ice core from Dronning Maud Land, Antarctica, aredetermined.As the considered medium is an ice-air composition, the real and imaginary partsof the constituents are subject to complex-valued mixing to form the measuredcomplex dielectric constant $\epsilon$.In contrast to earlier assumptions, correct frequency-scaling of $\epsilon$ requires complex decomposition of the dielectric constant at the 250~kHz DEP frequency to yield the frequency-independent properties, i.e.~density and conductivity,and has to be composed again at the 200 MHz radar frequency.Forcing of the numerical model with differently scaled and altered DEP data setsreveals the role of the initial physical parameters for the formation ofreflection horizons and enlights their isochronic characteristics, an importantapproach for interpreting internal reflection horizons. Conference Object Antarc* Antarctica Dronning Maud Land ice core Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Dronning Maud Land |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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description |
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.Although many different applications utilise internal reflection horizons, assuming that an individual reflector is isochronous, open questions concerningthe different reflection mechanisms remain.We demonstrate successful simulation of ice penetrating radar traces in polar ice by numerical finite-difference time-domain forward modeling.Based on a combined analyses of ice core records, radar surveys, and numerical sensitivity studies, we are able to provide better insights into the origin ofelectromagnetic reflections.By means of high resolution dielectric profiling (DEP) the physical properties of the upper 100 m of an ice core from Dronning Maud Land, Antarctica, aredetermined.As the considered medium is an ice-air composition, the real and imaginary partsof the constituents are subject to complex-valued mixing to form the measuredcomplex dielectric constant $\epsilon$.In contrast to earlier assumptions, correct frequency-scaling of $\epsilon$ requires complex decomposition of the dielectric constant at the 250~kHz DEP frequency to yield the frequency-independent properties, i.e.~density and conductivity,and has to be composed again at the 200 MHz radar frequency.Forcing of the numerical model with differently scaled and altered DEP data setsreveals the role of the initial physical parameters for the formation ofreflection horizons and enlights their isochronic characteristics, an importantapproach for interpreting internal reflection horizons. |
format |
Conference Object |
author |
Eisen, Olaf Wilhelms, Frank Nixdorf, Uwe Miller, Heinrich |
spellingShingle |
Eisen, Olaf Wilhelms, Frank Nixdorf, Uwe Miller, Heinrich Investigating the origin of shallow electromagnetic reflections in cold ice by finite-difference forward modeling |
author_facet |
Eisen, Olaf Wilhelms, Frank Nixdorf, Uwe Miller, Heinrich |
author_sort |
Eisen, Olaf |
title |
Investigating the origin of shallow electromagnetic reflections in cold ice by finite-difference forward modeling |
title_short |
Investigating the origin of shallow electromagnetic reflections in cold ice by finite-difference forward modeling |
title_full |
Investigating the origin of shallow electromagnetic reflections in cold ice by finite-difference forward modeling |
title_fullStr |
Investigating the origin of shallow electromagnetic reflections in cold ice by finite-difference forward modeling |
title_full_unstemmed |
Investigating the origin of shallow electromagnetic reflections in cold ice by finite-difference forward modeling |
title_sort |
investigating the origin of shallow electromagnetic reflections in cold ice by finite-difference forward modeling |
publishDate |
2003 |
url |
https://epic.awi.de/id/eprint/6103/ https://hdl.handle.net/10013/epic.16653 |
geographic |
Dronning Maud Land |
geographic_facet |
Dronning Maud Land |
genre |
Antarc* Antarctica Dronning Maud Land ice core |
genre_facet |
Antarc* Antarctica Dronning Maud Land ice core |
op_source |
EPIC3EGS 2003. |
op_relation |
Eisen, O. orcid:0000-0002-6380-962X , Wilhelms, F. orcid:0000-0001-7688-3135 , Nixdorf, U. and Miller, H. (2003) Investigating the origin of shallow electromagnetic reflections in cold ice by finite-difference forward modeling , EGS 2003. . hdl:10013/epic.16653 |
_version_ |
1776203242558980096 |