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https://doi.org/10.5194/egusphere-2025-150
https://doi.org/10.5194/egusphere-2025-150
12 Mar 2025
 | 12 Mar 2025

Modelling the evolution of permafrost temperatures and active layer thickness in King George Island, Antarctica, since 1950

Joana Pedro Baptista, Goncalo Brito Guapo Teles Vieira, Hyoungseok Lee, António Manuel de Carvalho Soares Correia, and Sebastian Westermann

Abstract. The dynamics of permafrost and the active layer is crucial for ecosystem processes in the ice-free areas of the Antarctic Peninsula, where a strong long-term warming trend, with an increase of 3.4 °C in the mean annual air temperature since 1950 has been recorded. The consequences of this warming on past and future permafrost degradation are still not fully understood, mainly due to the sparse spatial coverage and limited time span of borehole data, which have only been available since the mid to late 2000’s. This motivated the application of the CryoGrid Community Model for modelling ground temperatures at the bedrock drilled King Sejong Station borehole (KSS) in Barton Peninsula, King George Island. The objective was to assess the model's quality and potential for applicability in other ice-free areas of the Antarctic Peninsula, aiming to improve understanding of the recent evolution of permafrost temperature and active layer thickness and reconstitute the past evolution since 1950. ERA5 reanalysis data underestimated air temperature, strongly impacting the ground warming velocity and intensity in the shoulder seasons. Linear regression using in situ observations was used to correct the ERA5 forcing. The results of a short-term simulation from 2020–2022 evaluated against observations show that the model successfully represents the conditions at the KSS borehole. Down to 6 m depth correlations above 0.9 were obtained, while below 6 m, the correlations were above 0.8. Mean Absolute Error ranged from 0.1 to 0.7 °C. Active layer depths of 2.9 to 3.1 m showed an overestimation of c. 0.4 m. The long-term simulation of permafrost and active layer temperatures from 1950 to 2022 using ERA5 data showed a ground warming trend at 20 m of 0.25 °C/decade, accompanied by an increase of the active layer thickness of 2.0 m, from 1.5 m in 1950 to 3.5 m in 2022. The warming rate intensified significantly since 2015 to 0.9 °C/ decade.

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Journal article(s) based on this preprint

03 Sep 2025
Modelling the evolution of permafrost temperatures and active layer thickness in King George Island, Antarctica, since 1950
Joana Pedro Baptista, Gonçalo Brito Guapo Teles Vieira, António Manuel de Carvalho Soares Correia, Hyoungseok Lee, and Sebastian Westermann
The Cryosphere, 19, 3459–3476, https://doi.org/10.5194/tc-19-3459-2025,https://doi.org/10.5194/tc-19-3459-2025, 2025
Short summary
Joana Pedro Baptista, Goncalo Brito Guapo Teles Vieira, Hyoungseok Lee, António Manuel de Carvalho Soares Correia, and Sebastian Westermann

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2025-150', Anonymous Referee #1, 19 Mar 2025
    • AC1: 'Reply on RC1', Joana Baptista, 29 Apr 2025
  • RC2: 'Comment on egusphere-2025-150', Vladimir Romanovsky, 11 Apr 2025
    • AC2: 'Reply on RC2', Joana Baptista, 29 Apr 2025

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2025-150', Anonymous Referee #1, 19 Mar 2025
    • AC1: 'Reply on RC1', Joana Baptista, 29 Apr 2025
  • RC2: 'Comment on egusphere-2025-150', Vladimir Romanovsky, 11 Apr 2025
    • AC2: 'Reply on RC2', Joana Baptista, 29 Apr 2025

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
ED: Publish subject to revisions (further review by editor and referees) (30 Apr 2025) by Jeannette Noetzli
AR by Joana Baptista on behalf of the Authors (02 May 2025)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (20 May 2025) by Jeannette Noetzli
RR by Anonymous Referee #1 (20 Jun 2025)
ED: Publish as is (23 Jun 2025) by Jeannette Noetzli
AR by Joana Baptista on behalf of the Authors (23 Jun 2025)

Journal article(s) based on this preprint

03 Sep 2025
Modelling the evolution of permafrost temperatures and active layer thickness in King George Island, Antarctica, since 1950
Joana Pedro Baptista, Gonçalo Brito Guapo Teles Vieira, António Manuel de Carvalho Soares Correia, Hyoungseok Lee, and Sebastian Westermann
The Cryosphere, 19, 3459–3476, https://doi.org/10.5194/tc-19-3459-2025,https://doi.org/10.5194/tc-19-3459-2025, 2025
Short summary
Joana Pedro Baptista, Goncalo Brito Guapo Teles Vieira, Hyoungseok Lee, António Manuel de Carvalho Soares Correia, and Sebastian Westermann
Joana Pedro Baptista, Goncalo Brito Guapo Teles Vieira, Hyoungseok Lee, António Manuel de Carvalho Soares Correia, and Sebastian Westermann

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Short summary
Permafrost underlies ice-free areas of Antarctica, but its response to long-term warming is unclear due to a limited number of monitoring sites. To address this, we used the CryoGrid model, forced with climate data, to estimate permafrost temperatures and active layer thickness at King Sejong Station since 1950. The results show ground temperatures rising 0.25 °C per decade and the active layer thickening by 2 m. Warming has accelerated since 2015, highlighting the need for continued monitoring.
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