Aplicación de técnicas de georradar para determinar las interfaces entre hielo templado y hielo frío, neviza y nieve de los glaciares Hurd y Johnsons, isla Livingston, Antártida.

• Letamendia, Unai ^[1] ; Navarro, Francisco ^[1] ; Benjumea, Beatriz ^[2]
  1. [1] Universidad Politécnica de Madrid

     Universidad Politécnica de Madrid

     Madrid, España

     
  2. [2] Instituto Geológico y Minero de España

     Instituto Geológico y Minero de España

     Madrid, España

     
• Localización: 10.ª Asamblea Hispano-Portuguesa de Geodesia y Geofísica: artículos, 2023, ISBN 978-84-416-7540-7, págs. 1131-1136
• Idioma: español
• Títulos paralelos:
  • Application of ground-penetrating radar techniques to determining the interfaces between temperate and cold ice, firn and snow of Hurd-Johnsons glaciers, Livingston island, Antarctica.
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• Resumen

  • Knowledge of the internal structure of glaciers in terms of 3-D spatial distribution of their firn, temperate and cold layers is fundamental for an accurate modelling of their dynamics, as these materials have different rheological properties. Similarly, knowledge of the spatial distribution and thickness of the snow layer is critical for the estimation of accumulation in massbalance studies. Ground-penetrating radars (GPR) of suitable frequencies have been shown to be a useful tool for determining the interfaces between snow and either firn or ice, between the firn layer and the underlying ice, and between cold and temperate ice layers. The detection of such interfaces is based on the different permittivities of the intervening materials and the presence of interstitial water in temperate ice. In this study, we apply such techniques on Hurd and Johnsons glaciers, Livingston island, Antarctica. Data were collected in 2003/04, 2008/09 and 2016/17 field campaigns using 200 and 750 MHz GPRs. The higher vertical resolution of the high-frequency radar is suitable for the analysis of the shallowest structure, namely the snow cover. Mid-frequency radar, in turn, provides greater penetration, at the expense of a lower resolution, and allows analysing deeper structures, such as the firn or cold/temperate ice layers. GPR data processing is key to a proper detection of the interfaces between the various layers. The maximum thicknesses obtained for the snow, firn and cold ice layers were of 2.45, 26.9 and 79 m, respectively. The corresponding average thicknesses were of 1.44, 11.5 and 28 m. The position of the equilibrium line was determined independently from the firn and cold ice thickness maps. The consistency of the results supports their validity

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