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

• Main Authors: Kang, Haoran, Zhao, Liyun, Wolovick, Michael, Moore, John C.
• Format: Text
• Language: English
• Published: 2021
• Subjects: Antarctic; The Antarctic; East Antarctica; Amery; Amery Ice Shelf; Antarc*; Antarctica; Ice Sheet; Ice Shelf
• Online Access: https://doi.org/10.5194/tc-2021-357; https://tc.copernicus.org/preprints/tc-2021-357/

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.