Preprints
https://doi.org/10.5194/egusphere-2022-745
https://doi.org/10.5194/egusphere-2022-745
22 Aug 2022
 | 22 Aug 2022

Improving modelled albedo over the Greenland ice sheet through parameter optimisation and MODIS retrievals

Nina Raoult, Sylvie Charbit, Christophe Dumas, Fabienne Maignan, Catherine Ottlé, and Vladislav Bastrikov

Abstract. Greenland ice sheet mass loss continues to accelerate as global temperatures increase. The surface albedo of the ice sheet determines the amount of absorbed solar energy, which is a key factor in driving surface snow and ice melting. Satellite retrieved albedo allows us to compare and optimise modelled albedo over the entirety of the ice sheet. We optimise the parameters of the albedo scheme in the ORCHIDEE land surface model for three random years taken over the 2000–2017 period and validate over the remaining years. In particular, we want to improve the albedo at the edges of the ice sheet since they correspond to ablation areas and show the greatest variations in runoff and surface mass balance. By giving a larger weight to points at the ice sheet's edge, we improve the model-data fit by reducing the RMSD by over 25 % for the whole ice sheet for the summer months. This improvement is consistent for all years, even those not used in the calibration step. We conclude by showing which additional model outputs are impacted by changes to the albedo parameters encouraging future work using multiple data streams for optimisation.

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Journal article(s) based on this preprint

12 Jul 2023
Improving modelled albedo over the Greenland ice sheet through parameter optimisation and MODIS snow albedo retrievals
Nina Raoult, Sylvie Charbit, Christophe Dumas, Fabienne Maignan, Catherine Ottlé, and Vladislav Bastrikov
The Cryosphere, 17, 2705–2724, https://doi.org/10.5194/tc-17-2705-2023,https://doi.org/10.5194/tc-17-2705-2023, 2023
Short summary
Nina Raoult, Sylvie Charbit, Christophe Dumas, Fabienne Maignan, Catherine Ottlé, and Vladislav Bastrikov

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-745', Anonymous Referee #1, 17 Oct 2022
    • AC1: 'Reply on RC1', Nina Raoult, 02 Dec 2022
  • RC2: 'Comment on egusphere-2022-745', Anonymous Referee #2, 22 Oct 2022
    • AC2: 'Reply on RC2', Nina Raoult, 02 Dec 2022
  • EC1: 'Comment on egusphere-2022-745', Patricia de Rosnay, 04 Nov 2022

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-745', Anonymous Referee #1, 17 Oct 2022
    • AC1: 'Reply on RC1', Nina Raoult, 02 Dec 2022
  • RC2: 'Comment on egusphere-2022-745', Anonymous Referee #2, 22 Oct 2022
    • AC2: 'Reply on RC2', Nina Raoult, 02 Dec 2022
  • EC1: 'Comment on egusphere-2022-745', Patricia de Rosnay, 04 Nov 2022

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) (03 Dec 2022) by Patricia de Rosnay
AR by Nina Raoult on behalf of the Authors (11 Jan 2023)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (11 Jan 2023) by Patricia de Rosnay
RR by Anonymous Referee #3 (08 Feb 2023)
RR by Anonymous Referee #4 (22 Feb 2023)
ED: Publish subject to revisions (further review by editor and referees) (23 Feb 2023) by Patricia de Rosnay
AR by Nina Raoult on behalf of the Authors (06 Apr 2023)  Author's response   Author's tracked changes   Manuscript 
ED: Publish subject to revisions (further review by editor and referees) (19 Apr 2023) by Patricia de Rosnay
ED: Referee Nomination & Report Request started (19 Apr 2023) by Patricia de Rosnay
RR by Anonymous Referee #4 (30 Apr 2023)
RR by Anonymous Referee #3 (16 May 2023)
ED: Publish subject to minor revisions (review by editor) (26 May 2023) by Patricia de Rosnay
AR by Nina Raoult on behalf of the Authors (02 Jun 2023)  Author's response   Author's tracked changes   Manuscript 
ED: Publish as is (05 Jun 2023) by Patricia de Rosnay
AR by Nina Raoult on behalf of the Authors (08 Jun 2023)  Manuscript 

Journal article(s) based on this preprint

12 Jul 2023
Improving modelled albedo over the Greenland ice sheet through parameter optimisation and MODIS snow albedo retrievals
Nina Raoult, Sylvie Charbit, Christophe Dumas, Fabienne Maignan, Catherine Ottlé, and Vladislav Bastrikov
The Cryosphere, 17, 2705–2724, https://doi.org/10.5194/tc-17-2705-2023,https://doi.org/10.5194/tc-17-2705-2023, 2023
Short summary
Nina Raoult, Sylvie Charbit, Christophe Dumas, Fabienne Maignan, Catherine Ottlé, and Vladislav Bastrikov
Nina Raoult, Sylvie Charbit, Christophe Dumas, Fabienne Maignan, Catherine Ottlé, and Vladislav Bastrikov

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Short summary
Greenland ice sheet melting due to global warming could significantly impact the global sea-level rise. The ice sheet's albedo, i.e., how reflective the surface is, affects the melting speed. The ORCHIDEE computer model is used to simulate albedo and snow melt to make predictions. However, the albedo in ORCHIDEE is lower than that observed using satellites. To correct this, we change model parameters (e.g., the rate of snow decay) to reduce the difference between simulated and observed values.