Preprints
https://doi.org/10.5194/tc-2023-81
https://doi.org/10.5194/tc-2023-81
04 Jul 2023
 | 04 Jul 2023
Status: a revised version of this preprint was accepted for the journal TC and is expected to appear here in due course.

Impact of boundary conditions on the modelled thermal regime of the Antarctic ice sheet

In-Woo Park, Emilia Kyung Jin, Mathieu Morlighem, and Kang-Kun Lee

Abstract. A realistic initialization of ice flow models is critical for predicting future changes in ice sheet mass balance and their associated contribution to sea level rise. The initial thermal state of an ice sheet is particularly important as it controls ice viscosity and basal conditions, thereby influencing the overall ice velocity. Englacial and subglacial conditions, however, remain poorly understood due to insufficient direct measurements, which complicates the initialization and validation of thermal models. Here, we investigate the impact of using different geothermal heat flux (GHF) datasets and vertical velocity profiles on the thermal state of the Antarctic ice sheet, and compare our modeled temperatures to in situ measurements from 15 boreholes. We find that the vertical velocity plays a more important role in the temperature profile than GHF. More importantly, we find that the standard approach, which consists in combining basal sliding speed and incompressibility to derive vertical velocities, provides reasonably good results in fast flowing regions (ice velocity > 50 m yr-1), but performs poorly in slower moving regions.

In-Woo Park, Emilia Kyung Jin, Mathieu Morlighem, and Kang-Kun Lee

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2023-81', Tyler Pelle, 02 Aug 2023
    • AC1: 'Reply on RC1', In-Woo Park, 24 Sep 2023
  • RC2: 'Comment on tc-2023-81', Anonymous Referee #2, 15 Aug 2023
    • AC2: 'Reply on RC2', In-Woo Park, 24 Sep 2023

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2023-81', Tyler Pelle, 02 Aug 2023
    • AC1: 'Reply on RC1', In-Woo Park, 24 Sep 2023
  • RC2: 'Comment on tc-2023-81', Anonymous Referee #2, 15 Aug 2023
    • AC2: 'Reply on RC2', In-Woo Park, 24 Sep 2023
In-Woo Park, Emilia Kyung Jin, Mathieu Morlighem, and Kang-Kun Lee
In-Woo Park, Emilia Kyung Jin, Mathieu Morlighem, and Kang-Kun Lee

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Short summary
This study conducted 3D thermo-dynamic ice sheet model experiments, and modeled temperatures were compared with 15 observed borehole temperature profiles. We found that using an incompressibility of ice without sliding provides a good agreement with observed temperature profiles in slow flow regions, while incorporating sliding in fast flow regions captures observed temperature profiles. Also, a choice of vertical velocity scheme has a greater impact on shape of modeled temperature profile.