DOI: 10.5281/zenodo.15664172
title: Estimates of basal and englacial thermal conditions of the Antarctic ice sheet

description: This dataset contains the data and the MATLAB scripts required to reproduce the figures presented in the study:

"Estimates of basal and englacial thermal conditions of the Antarctic ice sheet"

 by Olivia Raspoet and Frank Pattyn (Journal of Glaciology, 2025).

 

 

Abstract

We conduct an ensemble of simulations of the englacial temperature field of the Antarctic ice sheet to gauge the sensitivity to uncertainties in geothermal heat flow, surface climatic conditions, ice thermodynamics and dynamics. We compare the modelled temperature fields with observational constraints, including deep-borehole temperature measurements, englacial temperatures retrieved from the Soil Moisture and Ocean Salinity satellite observations, and the distribution of subglacial lakes to determine the most likely boundary conditions. Results show that temperate basal conditions prevail over 60% of the Antarctic ice sheet, with a mean basal melt rate of 6.9 mm/a. The ensemble mean subglacial meltwater production over the grounded ice sheet is 69 Gt/a, with a contribution of 51% from geothermal heat and 49% from frictional heat. While geothermal heat flow remains the largest source of uncertainty, heat flow datasets leading to colder conditions tend to fit englacial temperature measurements better. However, ice thermomechanical approximations influence the shape of temperature profiles and may, in some cases, be more important than the geothermal heat flow. Furthermore, since frictional heat contributes significantly to basal melt in regions hosting fast-flowing glaciers, uncertainties in basal slipperiness affect the basal melt estimates as much as the geothermal heat flow.

 

 

Dataset



This dataset provides the results of the ensemble of simulations for the following variables:

- basal temperatures (2D)

- basal melt rates (2D)

- basal melting from geothermal heating (2D)

- basal melting from frictional heating (2D)

- subglacial water fluxes (2D)- englacial temperature (3D)

- englacial water content (3D)

- fraction of temperate basal conditions (1D)- subglacial meltwater volume (1D)

 

Results are provided in native MATLAB files (.mat) and converted to compressed NetCDF (.nc) for 2D and 3D variables and to text (.txt) for 1D variables. The Kori-ULB model and MATLAB scripts required to reproduce the figures are provided in MATLAB_SCRIPTS.zip. 

 



While all simulations are made available in this repository, users are encouraged to prioritize the outputs of the Kori-ULB model using the enthalpy method ('HySSAE_cst’), with geothermal heat flow datasets that allow a good fit with the observational constraints (’HF4’, ’HF9’) or are recommended by the geophysical community (’HF6’, ’HF7’).

 

For detailed information on file structure and variable descriptions, please refer to the ReadMe.md file.


 

 





Disclaimer

The MATLAB scripts are provided as-is without any warranties. The authors are not responsible for any inaccuracies or errors in the reproduced figure(s). Additional variables may be provided upon request from the authors.

 

 





Citation





When using this dataset, please cite the associated publication in addition to the Zenodo reference:

Raspoet, O., & Pattyn, F. (2025). Estimates of basal and englacial thermal conditions of the Antarctic ice sheet. Journal of Glaciology, 71, e104. doi:10.1017/jog.2025.10087

 

 

Acknowledgements





This publication was generated in the frame of Beyond EPICA. The project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 815384 (Oldest Ice Core). It is supported by national partners and funding agencies in Belgium, Denmark, France, Germany, Italy, Norway, Sweden, Switzerland, The Netherlands and the United Kingdom. Logistic support is mainly provided by ENEA and IPEV through the Concordia Station system.

The SMOS data used in this study (Macelloni and others, 2019) have been developed in the ESA Project - “Cryosmos. STSE SMOS+Cryosphere”. ESA contract No.4000112262/14/I-NB.

Computational resources have been provided by the Consortium des Équipements de Calcul Intensif (CÉCI), funded by the Fonds de la Recherche Scientifique de Belgique (F.R.S.-FNRS) under Grant No. 2.5020.11 and by the Walloon Region.

Olivia Raspoet is a FRIA grantee of the Fonds de la Recherche Scientifique de Belgique (F.R.S.-FNRS).


 

ReferencesReferences are listed in the ReadMe.md file and in the published paper.