Investigating the Radar Response of Englacial Debris Entrained Basal Ice Units in East Antarctica Using Electromagnetic Forward Modeling

Steven Franke*, Tamara Gerber, Craig Warren, Daniela Jansen, Olaf Eisen, Dorthe Dahl-Jensen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

5 Citations (Scopus)
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Abstract

Radio-echo sounding (RES) reveals patches of high backscatter in basal ice units, which represent distinct englacial features in the bottom parts of glaciers and ice sheets. Their material composition and physical properties are largely unknown due to their direct inaccessibility but could provide significant information on the physical state as well as on present and past processes at the ice-sheet base. Here, we investigate the material properties of basal ice units by comparing measured airborne radar data with synthetic radar responses generated using electromagnetic (EM) forward modeling. The observations were acquired at the onset of the Jutulstraumen Ice Stream in western Dronning Maud Land (DML) (East Antarctica) and show strong continuous near-basal reflections of up to 200-m thickness in the normally echo-free zone (EFZ). Based on our modeling, we suggest that these high-backscatter units are most likely composed of point reflectors with low dielectric properties, suggesting thick packages of englacial entrained debris. We further investigate the effects of entrained particle size, and concentration in combination with different dielectric properties, which provide useful information to constrain the material composition of radar-detected units of high backscatter. The capability and application of radar wave modeling in complex englacial environments is therefore a valuable tool to further constrain the composition of basal ice and the physical conditions at the ice base.

Original languageEnglish
Article number4301516
JournalIEEE Transactions on Geoscience and Remote Sensing
Volume61
Number of pages16
ISSN0196-2892
DOIs
Publication statusPublished - 19 May 2023

Bibliographical note

Publisher Copyright:
© 1980-2012 IEEE.

Keywords

  • Antarctic ice sheet
  • basal freeze-on
  • basal ice
  • electromagnetic (EM) forward modeling
  • gprMax
  • ice accretion
  • Jutulstraumen ice stream
  • radio-echo sounding (RES)
  • sediment entrainment

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