Preprints
https://doi.org/10.5194/egusphere-2024-3728
https://doi.org/10.5194/egusphere-2024-3728
10 Jan 2025
 | 10 Jan 2025

The surface mass balance and near-surface climate of the Antarctic ice sheet in RACMO2.4p1

Christiaan T. van Dalum, Willem Jan van de Berg, Michiel R. van den Broeke, and Maurice van Tiggelen

Abstract. This study presents a new near-surface climate and surface mass balance (SMB) product for Antarctica for the historical period (1960–2023) using the updated version of the Regional Atmospheric Climate Model (RACMO), version 2.4p1 (R24). We study the impact of the major updates implemented in R24 on the climate of Antarctica, and show that the SMB, surface energy budget, albedo, pressure, temperature and wind speed compare well with observations. Compared to preceding RACMO versions, the advection of snow hydrometeors and alterations in the blowing snow parameterization affect the SMB, resulting in more precipitation in the mountains of West Antarctica and the Antarctic Peninsula, and an alternating pattern of SMB changes in the coastal zones of East Antarctica. Integrated over the ice sheet, including ice shelves, the modeled SMB is 2546 Gt yr-1, with an inter-annual variability of 133 Gt yr-1. Melt fluxes are small in Antarctica, at 124 Gt yr-1 and an inter-annual variability of 31 Gt yr-1, but can be significant on ice shelves, locally exceeding 500 mm water equivalent yr-1. The presence of melt water in snow compares remarkably well with remote sensing observations and has improved compared to the previous operational RACMO version, 2.3p2. Temperature, shortwave radiative fluxes and albedo are modeled well compared to in-situ observations. Longwave radiative and turbulent fluxes, however, require further model developments.

Competing interests: At least one of the (co-)authors is a member of the editorial board of The Cryosphere. The peer-review process was guided by an independent editor, and the authors also have no other competing interests to declare.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
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Journal article(s) based on this preprint

29 Sep 2025
The surface mass balance and near-surface climate of the Antarctic ice sheet in RACMO2.4p1
Christiaan T. van Dalum, Willem Jan van de Berg, Michiel R. van den Broeke, and Maurice van Tiggelen
The Cryosphere, 19, 4061–4090, https://doi.org/10.5194/tc-19-4061-2025,https://doi.org/10.5194/tc-19-4061-2025, 2025
Short summary
Christiaan T. van Dalum, Willem Jan van de Berg, Michiel R. van den Broeke, and Maurice van Tiggelen

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-3728', Anonymous Referee #1, 26 Feb 2025
    • AC1: 'Reply on RC1', Christiaan van Dalum, 19 May 2025
  • RC2: 'Comment on egusphere-2024-3728', Josep Bonsoms, 22 Apr 2025
    • AC2: 'Reply on RC2', Christiaan van Dalum, 19 May 2025

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-3728', Anonymous Referee #1, 26 Feb 2025
    • AC1: 'Reply on RC1', Christiaan van Dalum, 19 May 2025
  • RC2: 'Comment on egusphere-2024-3728', Josep Bonsoms, 22 Apr 2025
    • AC2: 'Reply on RC2', Christiaan van Dalum, 19 May 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) (23 May 2025) by Thomas Mölg
AR by Christiaan van Dalum on behalf of the Authors (23 May 2025)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (28 May 2025) by Thomas Mölg
RR by Anonymous Referee #1 (10 Jun 2025)
ED: Publish subject to minor revisions (review by editor) (13 Jun 2025) by Thomas Mölg
AR by Christiaan van Dalum on behalf of the Authors (19 Jun 2025)  Author's response   Author's tracked changes   Manuscript 
ED: Publish subject to technical corrections (30 Jun 2025) by Thomas Mölg
AR by Christiaan van Dalum on behalf of the Authors (14 Jul 2025)  Manuscript 

Journal article(s) based on this preprint

29 Sep 2025
The surface mass balance and near-surface climate of the Antarctic ice sheet in RACMO2.4p1
Christiaan T. van Dalum, Willem Jan van de Berg, Michiel R. van den Broeke, and Maurice van Tiggelen
The Cryosphere, 19, 4061–4090, https://doi.org/10.5194/tc-19-4061-2025,https://doi.org/10.5194/tc-19-4061-2025, 2025
Short summary
Christiaan T. van Dalum, Willem Jan van de Berg, Michiel R. van den Broeke, and Maurice van Tiggelen

Data sets

Monthly RACMO2.4p1 data for Antarctica (11 km) for SMB, SEB and near-surface variables (1979-2023) Christiaan van Dalum, Willem Jan van de Berg, and Michiel van den Broeke https://doi.org/10.5281/zenodo.14217232

Monthly RACMO2.4p1 data for Antarctica (11 km) for SMB, SEB and near-surface variables (1979-2023) Christiaan van Dalum, Willem Jan van de Berg, and Michiel van den Broeke https://doi.org/10.5281/zenodo.14217232

Christiaan T. van Dalum, Willem Jan van de Berg, Michiel R. van den Broeke, and Maurice van Tiggelen

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Short summary
In this study, we present a new surface mass balance (SMB) and near-surface climate product for Antarctica with the regional climate model RACMO2.4p1. We assess the impact of major model updates on the climate of Antarctica. Locally, the SMB has changed substantially, but also agrees well with observations. In addition, we show that the SMB components, surface energy budget, albedo, pressure, temperature and wind speed compare well with in-situ and remote sensing observations.
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