Preprints
https://doi.org/10.5194/tc-2021-357
https://doi.org/10.5194/tc-2021-357
 
30 Nov 2021
30 Nov 2021
Status: a revised version of this preprint is currently under review for the journal TC.

Evaluation of six geothermal heat flux maps for the Antarctic Lambert-Amery glacial system

Haoran Kang1, Liyun Zhao1,2, Michael Wolovick1,5, and John C. Moore1,3,4 Haoran Kang et al.
  • 1College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China
  • 2Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), China
  • 3CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China
  • 4Arctic Centre, University of Lapland, Rovaniemi, Finland
  • 5Alfred Wegener Institute, Bremerhaven, Germany

Abstract. Basal thermal conditions play an important role in ice sheet dynamics, and they are sensitive to geothermal heat flux (GHF). Here we estimate the basal thermal conditions, including basal temperature, basal melt rate, and friction heat underneath the Lambert-Amery glacier system in east Antarctica, using a combination of a forward model and an inversion from a 3D ice flow model. We assess the sensitivity and uncertainty of basal thermal conditions using six different GHFs. We evaluate the modelled results using all available observed subglacial lakes. There are very large differences in modelled spatial pattern of temperate basal conditions using the different GHFs. The two most-recent GHF fields inverted from aerial geomagnetic observations have higher values of GHF in the region, produce a larger warm-based area, and match the observed subglacial lakes better than the other GHFs. The fast flowing glacier region has a lower modelled basal friction coefficient, faster basal velocity, with higher basal frictional heating in the range of 50–2000 mW m−2 than the base under slower flowing glaciated areas. The modelled basal melt rate reaches ten to hundreds of mm per year locally in Lambert, Lepekhin and Kronshtadtskiy glaciers feeding the Amery ice shelf, and ranges from 0–5 mm yr−1 on the temperate base of the vast inland region.

Haoran Kang et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2021-357', William Colgan, 10 Jan 2022
    • AC1: 'Reply on RC1', Liyun Zhao, 19 Apr 2022
  • RC2: 'Comment on tc-2021-357', Anonymous Referee #2, 11 Feb 2022
    • AC2: 'Reply on RC2', Liyun Zhao, 19 Apr 2022
  • RC3: 'Comment on tc-2021-357', Anonymous Referee #3, 23 Feb 2022
    • AC3: 'Reply on RC3', Liyun Zhao, 19 Apr 2022

Haoran Kang et al.

Haoran Kang et al.

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Short summary
Basal thermal conditions are important to ice dynamics, and sensitive to geothermal heat flux (GHF). We estimate basal thermal conditions of the Lambert-Amery glacier system with six GHFs. The two most-recent GHFs inverted from aerial geomagnetic observations produce a larger warm-based area, and match the observed subglacial lakes better than the other GHFs. The modelled basal melt rate is ten to hundreds of mm per year in fast flowing glaciers feeding Amery ice shelf, and smaller inland.