A Multi-‐Method Approach to the Dielectric Properties of Natural Firn and Ice at kHZ- and Radio Frequencies
Precise knowledge of the dielectric properties of natural snow, firn and ice are essential for electromagnetic remote sensing of the cryosphere. In glaciological applications, the vertical distribution of dielectric properties can be obtained from ice core measurements by means of dielectric profili...
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ftawi:oai:epic.awi.de:34947 2023-05-15T16:39:01+02:00 A Multi-‐Method Approach to the Dielectric Properties of Natural Firn and Ice at kHZ- and Radio Frequencies Bohleber, P. Hackel, M. Eisen, Olaf Wilhelms, Frank Wagner, N. 2014-03-20 https://epic.awi.de/id/eprint/34947/ https://hdl.handle.net/10013/epic.43266 unknown Bohleber, P. , Hackel, M. , Eisen, O. orcid:0000-0002-6380-962X , Wilhelms, F. orcid:0000-0001-7688-3135 and Wagner, N. (2014) A Multi-‐Method Approach to the Dielectric Properties of Natural Firn and Ice at kHZ- and Radio Frequencies , 13th International Conference on the Physics and Chemistry of Ice (PCI- 2014), Hanover, NH, USA, 17 March 2014 - 20 March 2014 . hdl:10013/epic.43266 EPIC313th International Conference on the Physics and Chemistry of Ice (PCI- 2014), Hanover, NH, USA, 2014-03-17-2014-03-20 Conference notRev 2014 ftawi 2021-12-24T15:39:21Z Precise knowledge of the dielectric properties of natural snow, firn and ice are essential for electromagnetic remote sensing of the cryosphere. In glaciological applications, the vertical distribution of dielectric properties can be obtained from ice core measurements by means of dielectric profiling (DEP), nowadays routinely used in polar drillings. Dielectric profiles allow to link ice core properties with coherent reflections seen in ground-penetrating radar (GPR) by means of forward modeling GPR signals. However, as DEP operates at a few 100 kHz, the results have to be transferred to radio frequencies in the MHz-range. Here we investigate the dielectric properties of ice cores recently drilled at two cold glaciers in the European Alps, Col du Dome, Mont Blanc and Colle Gnifetti, Monte Rosa. Although limited to roughly 100 m in thickness, these glaciers comprise strong gradients in ice characteristics, such as impurity content and crystal orientation fabric, as well as a comparatively large depth-fraction of firn. We applied, for the first time, DEP to these Alpine ice cores. With respect to what is known from polar sites, dielectric profiles at 250 kHz are compared to density, impurity and electrical conductivity measurements. This is to obtain a comprehensive picture on the DEP signals in view of the strong variability in physical properties, and the potential for obtaining DEP-based age information from annual cycles and signatures of volcanic eruptions. Complementary to DEP, we used a coaxial cell setup to measure dielectric properties of selected firn samples directly at radio frequencies from 1 MHz to 1.5 GHz. This combined approach allows us to study the dielectric properties of natural samples over a broad frequency range and to assess the transfer of DEP results to radio frequencies. Finally we include a comparison of forward modeled and measured GPR signals aimed at an improved understanding of englacial reflections at these cold-ice mountain drilling sites. Conference Object ice core Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Mont Blanc ENVELOPE(69.468,69.468,-49.461,-49.461) Monte Rosa ENVELOPE(162.850,162.850,-70.917,-70.917) |
institution |
Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
Precise knowledge of the dielectric properties of natural snow, firn and ice are essential for electromagnetic remote sensing of the cryosphere. In glaciological applications, the vertical distribution of dielectric properties can be obtained from ice core measurements by means of dielectric profiling (DEP), nowadays routinely used in polar drillings. Dielectric profiles allow to link ice core properties with coherent reflections seen in ground-penetrating radar (GPR) by means of forward modeling GPR signals. However, as DEP operates at a few 100 kHz, the results have to be transferred to radio frequencies in the MHz-range. Here we investigate the dielectric properties of ice cores recently drilled at two cold glaciers in the European Alps, Col du Dome, Mont Blanc and Colle Gnifetti, Monte Rosa. Although limited to roughly 100 m in thickness, these glaciers comprise strong gradients in ice characteristics, such as impurity content and crystal orientation fabric, as well as a comparatively large depth-fraction of firn. We applied, for the first time, DEP to these Alpine ice cores. With respect to what is known from polar sites, dielectric profiles at 250 kHz are compared to density, impurity and electrical conductivity measurements. This is to obtain a comprehensive picture on the DEP signals in view of the strong variability in physical properties, and the potential for obtaining DEP-based age information from annual cycles and signatures of volcanic eruptions. Complementary to DEP, we used a coaxial cell setup to measure dielectric properties of selected firn samples directly at radio frequencies from 1 MHz to 1.5 GHz. This combined approach allows us to study the dielectric properties of natural samples over a broad frequency range and to assess the transfer of DEP results to radio frequencies. Finally we include a comparison of forward modeled and measured GPR signals aimed at an improved understanding of englacial reflections at these cold-ice mountain drilling sites. |
format |
Conference Object |
author |
Bohleber, P. Hackel, M. Eisen, Olaf Wilhelms, Frank Wagner, N. |
spellingShingle |
Bohleber, P. Hackel, M. Eisen, Olaf Wilhelms, Frank Wagner, N. A Multi-‐Method Approach to the Dielectric Properties of Natural Firn and Ice at kHZ- and Radio Frequencies |
author_facet |
Bohleber, P. Hackel, M. Eisen, Olaf Wilhelms, Frank Wagner, N. |
author_sort |
Bohleber, P. |
title |
A Multi-‐Method Approach to the Dielectric Properties of Natural Firn and Ice at kHZ- and Radio Frequencies |
title_short |
A Multi-‐Method Approach to the Dielectric Properties of Natural Firn and Ice at kHZ- and Radio Frequencies |
title_full |
A Multi-‐Method Approach to the Dielectric Properties of Natural Firn and Ice at kHZ- and Radio Frequencies |
title_fullStr |
A Multi-‐Method Approach to the Dielectric Properties of Natural Firn and Ice at kHZ- and Radio Frequencies |
title_full_unstemmed |
A Multi-‐Method Approach to the Dielectric Properties of Natural Firn and Ice at kHZ- and Radio Frequencies |
title_sort |
multi-‐method approach to the dielectric properties of natural firn and ice at khz- and radio frequencies |
publishDate |
2014 |
url |
https://epic.awi.de/id/eprint/34947/ https://hdl.handle.net/10013/epic.43266 |
long_lat |
ENVELOPE(69.468,69.468,-49.461,-49.461) ENVELOPE(162.850,162.850,-70.917,-70.917) |
geographic |
Mont Blanc Monte Rosa |
geographic_facet |
Mont Blanc Monte Rosa |
genre |
ice core |
genre_facet |
ice core |
op_source |
EPIC313th International Conference on the Physics and Chemistry of Ice (PCI- 2014), Hanover, NH, USA, 2014-03-17-2014-03-20 |
op_relation |
Bohleber, P. , Hackel, M. , Eisen, O. orcid:0000-0002-6380-962X , Wilhelms, F. orcid:0000-0001-7688-3135 and Wagner, N. (2014) A Multi-‐Method Approach to the Dielectric Properties of Natural Firn and Ice at kHZ- and Radio Frequencies , 13th International Conference on the Physics and Chemistry of Ice (PCI- 2014), Hanover, NH, USA, 17 March 2014 - 20 March 2014 . hdl:10013/epic.43266 |
_version_ |
1766029375911755776 |