the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 06 May 2024
First results of the polar regional climate model RACMO2.4
Abstract. A next version of the polar regional climate model RACMO (referred to as RACMO2.4p1) is presented in this study. The principal update includes embedding of the package of physical parameterizations of the Integrated Forecast System (IFS) cycle 47r1. This constitutes changes in the precipitation, convection, turbulence, aerosol and surface schemes, and includes a new cloud scheme with more prognostic variables and a dedicated lake model. Furthermore, the stand-alone IFS radiation physics module ecRad is incorporated in RACMO, and a multi-layer snow module for non-glaciated regions is introduced. Other updates involve the introduction of a fractional land-ice mask, new and updated climatological data sets, such as aerosol concentrations and leaf-area index, and the revision of several parameterizations specific to glaciated regions. As a proof of concept, we show first results for Greenland, Antarctica and a region encompassing the Arctic. By comparing the results with observations and the output from the previous model version (RACMO2.3p3), we show that the model performs well regarding the surface mass balance, surface energy balance, temperature, wind speed, cloud content and snow depth. The advection of snow hydrometeors strongly impacts the ice sheet's local surface mass balance, particularly in high-accumulation regions such as southeast Greenland and the Antarctic Peninsula. We critically assess the model output and identify some processes that would benefit from further model development.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
(8335 KB)
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
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- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2024-895', Oskar Landgren, 07 Jun 2024
The authors present a thorough overview of the changes included in the updated version of the regional climate model RACMO, with many improvements tuned for the polar regions.
Evaluation includes comparison against comprehensive meteorological station datasets, but is otherwise mostly focusing on comparisons with the previous model version. While that indirectly (via articles referred to in the paper of evaluation of the previous version) enables comparison against remote sensing datasets, it would have been nice to see some figures where spatial patterns can be more closely examined for both model versions, for example against the mentioned CALIOP/CALIPSO dataset, or maybe MODIS or CLARA? Noting that the use of satellite data in the polar regions has its own issues (few near-pole overpasses, persistent cloud cover, lack of in-situ data for validation etc.) I think the current approach is fine.
All in all, I find the manuscript well-written with a good structure and sound conclusions.
I have only a few minor comments before I can recommend accepting it:L67-68: Please explain a little bit more what "flexibility" refers to in the sentence "recoded in order to improve code readability and flexibility". Does it for example include code refactoring, or make it easier to adapt to heterogeneous hardware in the future?
L254-255: If I understood it correctly, you use fractional glacier cover. Does the sentence "Only measurement sites that are also located on a glaciated grid point in RACMO are included in this study" mean you are using cells with 100% glacier cover, or another threshold?
L266: Please motivate why the exclusion threshold is set as low as one missing hour per day. It sounds a bit aggressive to me, but perhaps there are very few days with only a few hours missing.
L342-343: MAR results are not shown for comparison. Consider being more explicit, for example "compare Fig. 3a with Fig. X of Fettweis et al. 2020", or adding "(not shown)", or dropping this sentence entirely.
I would personally prefer to have some of the figures use inverted colour scales, so that blue would indicate more water/snow/ice (in analogy with cooler temperature being illustrated with blue color) and red for less.
This applies to Figures 2, 3b, 8b and 10.
I can see that you may want to use red for positive changes for consistency (e.g. in Fig. 5 where you use the same colourbar for all panels), so I don't insist on you to take this comment into account.Typos:
L90: M in model should not be capitalised.
L379: "such S6 or S7" -> "such as S6 or S7"
L450: "Between -80 to -40 °C" -> "Between -80 and -40 °C"Citation: https://doi.org/10.5194/egusphere-2024-895-RC1 - AC1: 'Reply on RC1', Christiaan van Dalum, 14 Jun 2024
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RC2: 'Comment on egusphere-2024-895', Anonymous Referee #2, 10 Jun 2024
In the paper by van Dalum et al., a thorough description is presented of the newest version of the polar regional climate model RACMO, version 2.4. The model is described, and a comparison is presented with the previous version and with observations.
The paper is very well written, the descriptions are thorough though still easily readable, and the results are well presented. It is recommended to be published after a very few adaptations.
Further, the results look very promising, particularly the effects of snow advection.
In Section 6, there are quantitative estimates of model bias for Arctic snow depth; it would improve the paper if some more qualitative considerations would be added: Is the current model good enough for intended uses related to this field? What are relative errors, etc. You might also consider to move this (Arctic) section before the Antarctic Section 5.
Minor comment: There seems to be no reference to Table 2 in the text even though numbers from the table are discussed.
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Citation: https://doi.org/10.5194/egusphere-2024-895-RC2 - AC2: 'Reply on RC2', Christiaan van Dalum, 14 Jun 2024
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2024-895', Oskar Landgren, 07 Jun 2024
The authors present a thorough overview of the changes included in the updated version of the regional climate model RACMO, with many improvements tuned for the polar regions.
Evaluation includes comparison against comprehensive meteorological station datasets, but is otherwise mostly focusing on comparisons with the previous model version. While that indirectly (via articles referred to in the paper of evaluation of the previous version) enables comparison against remote sensing datasets, it would have been nice to see some figures where spatial patterns can be more closely examined for both model versions, for example against the mentioned CALIOP/CALIPSO dataset, or maybe MODIS or CLARA? Noting that the use of satellite data in the polar regions has its own issues (few near-pole overpasses, persistent cloud cover, lack of in-situ data for validation etc.) I think the current approach is fine.
All in all, I find the manuscript well-written with a good structure and sound conclusions.
I have only a few minor comments before I can recommend accepting it:L67-68: Please explain a little bit more what "flexibility" refers to in the sentence "recoded in order to improve code readability and flexibility". Does it for example include code refactoring, or make it easier to adapt to heterogeneous hardware in the future?
L254-255: If I understood it correctly, you use fractional glacier cover. Does the sentence "Only measurement sites that are also located on a glaciated grid point in RACMO are included in this study" mean you are using cells with 100% glacier cover, or another threshold?
L266: Please motivate why the exclusion threshold is set as low as one missing hour per day. It sounds a bit aggressive to me, but perhaps there are very few days with only a few hours missing.
L342-343: MAR results are not shown for comparison. Consider being more explicit, for example "compare Fig. 3a with Fig. X of Fettweis et al. 2020", or adding "(not shown)", or dropping this sentence entirely.
I would personally prefer to have some of the figures use inverted colour scales, so that blue would indicate more water/snow/ice (in analogy with cooler temperature being illustrated with blue color) and red for less.
This applies to Figures 2, 3b, 8b and 10.
I can see that you may want to use red for positive changes for consistency (e.g. in Fig. 5 where you use the same colourbar for all panels), so I don't insist on you to take this comment into account.Typos:
L90: M in model should not be capitalised.
L379: "such S6 or S7" -> "such as S6 or S7"
L450: "Between -80 to -40 °C" -> "Between -80 and -40 °C"Citation: https://doi.org/10.5194/egusphere-2024-895-RC1 - AC1: 'Reply on RC1', Christiaan van Dalum, 14 Jun 2024
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RC2: 'Comment on egusphere-2024-895', Anonymous Referee #2, 10 Jun 2024
In the paper by van Dalum et al., a thorough description is presented of the newest version of the polar regional climate model RACMO, version 2.4. The model is described, and a comparison is presented with the previous version and with observations.
The paper is very well written, the descriptions are thorough though still easily readable, and the results are well presented. It is recommended to be published after a very few adaptations.
Further, the results look very promising, particularly the effects of snow advection.
In Section 6, there are quantitative estimates of model bias for Arctic snow depth; it would improve the paper if some more qualitative considerations would be added: Is the current model good enough for intended uses related to this field? What are relative errors, etc. You might also consider to move this (Arctic) section before the Antarctic Section 5.
Minor comment: There seems to be no reference to Table 2 in the text even though numbers from the table are discussed.
Â
Citation: https://doi.org/10.5194/egusphere-2024-895-RC2 - AC2: 'Reply on RC2', Christiaan van Dalum, 14 Jun 2024
Peer review completion
Journal article(s) based on this preprint
Data sets
Monthly RACMO2.4p1 data for Greenland (11 km) and Antarctica (27 km) for SMB, SEB, near-surface temperature and wind speed (2006-2015) Christiaan van Dalum, Willem Jan van de Berg, and Michiel van den Broeke https://doi.org/10.5281/zenodo.10854319
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Cited
1 citations as recorded by crossref.
Christiaan T. van Dalum
Willem Jan van de Berg
Srinidhi N. Gadde
Maurice van Tiggelen
Tijmen van der Drift
Erik van Meijgaard
Lambertus H. van Ulft
Michiel R. van den Broeke
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(8335 KB) - Metadata XML