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| Titel |
Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric |
| VerfasserIn |
O. Eisen, I. Hamann, S. Kipfstuhl, D. Steinhage, F. Wilhelms |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 1, no. 1 ; Nr. 1, no. 1 (2007-10-19), S.1-10 |
| Datensatznummer |
250000105
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| Publikation (Nr.) |
 copernicus.org/tc-1-1-2007.pdf |
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| Zusammenfassung |
| The origin of a strong continuous radar reflector observed with airborne
radio-echo sounding (RES) at the EPICA deep-drilling site in Dronning Maud
Land, Antarctica, is identified as a transition in crystal fabric orientation
from a vertical girdle to an increased single-pole orientation seen along the
ice core. The reflector is observed with a 60 ns and 600 ns long pulse at a
frequency of 150 MHz, spans one pulse length, is continuous over 5 km, and
occurs at a depth of about 2025–2045 m at the drill site. Changes in
conductivity as reflector origin are excluded by investigating the ice-core
profile, synthetic RES data, and a RES profile with different electromagnetic
polarisation azimuths. The reflector's magnitude shows maximum values for
polarisation parallel to the nearby ice divide and disappears for
polarisation perpendicular to it, identifying the orientation of the girdle
to lie in the vertical plane parallel to the ice divide. Observations allow
us to extrapolate the crystal orientation feature along the reflector in
space, with implications for ice-sheet dynamics and modeling. |
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