Ice thickness from radio-echo sounding (RES) and radar attenuation from numerical modelling for Recovery Glacier, Antarctica, supplement to: Humbert, Angelika; Steinhage, Daniel; Helm, Veit; Beyer, Sebastian; Kleiner, Thomas (2018): Missing Evidence of Widespread Subglacial Lakes at Recovery Glacier, Antarctica. Journal of Geophysical Research-Earth Surface, 123(11), 2802-2826

Recovery Glacier reaches far into the East Antarctic Ice Sheet. Recent projections point out that its dynamic behaviour has a considerable impact on future Antarctic ice loss (Golledge et al. 2017). Subglacial lakes are thought to play a major role in the initiation of the rapid ice flow (Bell et al...

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Bibliographic Details
Main Authors: Humbert, Angelika, Steinhage, Daniel, Helm, Veit, Beyer, Sebastian, Kleiner, Thomas
Format: Article in Journal/Newspaper
Language:English
Published: PANGAEA - Data Publisher for Earth & Environmental Science 2018
Subjects:
Glaciology @ AWI AWI_Glac
Antarctic
East Antarctic Ice Sheet
Recovery Glacier
Antarc*
Antarctica
Ice Sheet
Online Access:https://dx.doi.org/10.1594/pangaea.894294
https://doi.pangaea.de/10.1594/PANGAEA.894294
Description
Summary:Recovery Glacier reaches far into the East Antarctic Ice Sheet. Recent projections point out that its dynamic behaviour has a considerable impact on future Antarctic ice loss (Golledge et al. 2017). Subglacial lakes are thought to play a major role in the initiation of the rapid ice flow (Bell et al. 2007). Satellite altimetry observations have even suggested several actively filling and draining subglacial lakes beneath the main trunk (Smith et al. 2009). We present new data of the geometry of this glacier and investigate its basal properties employing radio-echo sounding. Using ice-sheet modelling, we were able to constrain estimates of radar absorption in the ice, but uncertainties remain large. The magnitude of the basal reflection coefficient is thus still poorly known. However, its spatial variability, in conjunction with additional indicators, can be used to infer the presence of subglacial water. We find no clear evidence of water at most of the previously proposed lake sites. Especially locations where altimetry detected active lakes, do not exhibit lake characteristics in RES. We argue that lakes far upstream the main trunk are not triggering enhanced ice flow, which is also supported by modeled subglacial hydrology.

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