OBLIMAP 2.0: a fast climate model–ice sheet model coupler including online embeddable mapping routines

Reerink, Thomas J.; van de Berg, Willem Jan; van de Wal, Roderik S. W.

doi:https://doi.org/10.5194/gmd-9-4111-2016

Articles | Volume 9, issue 11

https://doi.org/10.5194/gmd-9-4111-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/gmd-9-4111-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 9, issue 11

Model description paper

|

21 Nov 2016

Model description paper |

| 21 Nov 2016

OBLIMAP 2.0: a fast climate model–ice sheet model coupler including online embeddable mapping routines

Thomas J. Reerink, Willem Jan van de Berg, and Roderik S. W. van de Wal

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Final revised paper (published on 21 Nov 2016)
Supplement to the final revised paper
Preprint (discussion started on 02 Jun 2016)
Supplement to the preprint

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Review of Reerink and van de Wal 2016: Fast GCM – ice sheet model coupling software OBLIMAP 2.0, including on-line embeddable mapping routines', Anonymous Referee #1, 29 Jun 2016
- AC1: 'Response to review 1', Thomas Reerink, 23 Aug 2016
RC2: 'Comments on the manuscript “Fast GCM - ice sheet model coupling software OBLIMAP 2.0”, including on-line embeddable mapping routines', Florence COLLEONI, 29 Jun 2016
- AC2: 'Response to review 2', Thomas Reerink, 23 Aug 2016

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Thomas Reerink on behalf of the Authors (17 Sep 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (26 Sep 2016) by Jeremy Fyke

RR by Anonymous Referee #1 (10 Oct 2016)

Suggestions for revision or reasons for rejection

This is a resubmission of a paper that I previously reviewed, for which my recommendation was: “I was not convinced that OBLIMAP v. 2 has sufficient novelty or improvements relative to alternatives to warrant its publication in GMD.”

I appreciate the detailed replies that the authors have made to my earlier points, and feel that this new version is significantly improved. The authors have now convinced me of some of the advantages of OBLIMAP relative to other existing tools. I still remain unconvinced of some of the advantages the authors proclaim. For example, the MCT/ESMF-based cpl7 offers support for a number of the features that the authors highlighted in their response, including masking, merging and sparse matrices. I do acknowledge, though, that the user has to perform their own projection to convert regional, Cartesian coordinates to spherical coordinates. It appears that what’s really needed is some closer – perhaps face-to-face – communication between these authors and the authors of other coupling tools: Based on their response, it appears that their review of alternative coupling approaches has been cursory, and it seems that more direct communication would be mutually beneficial – allowing various groups to better evaluate the capabilities and limitations of each approach. Also, perhaps I am trying to fit OBLIMAP into the box I need and am most familiar with – a robust, online, conservative coupler – whereas perhaps OBLIMAP’s main applicability lies in offline regridding.

Regarding conservation: The authors state that their scheme comes close to conserving in the “to and fro” case, in practice. However, I would argue that that is too weak of a test: For example, in our situation, we remap from the land grid to the ice sheet grid using a scheme for which you could imagine using OBLIMAP, but then map the calving flux from the ice sheet to the ocean using a nearest-neighbor scheme. Thus, you cannot rely on error cancellation to deal with conservation errors arising from the initial mapping.

Nevertheless, I am comfortable with publication of the current manuscript essentially as is. The one point that needs to be addressed is that there are some minor grammatical errors in the new text; a few selected examples are:
- p 2, L 6: “Other components like e.g. for the atmospheric chemistry”
- p 9, L 7: “saves the user to figure out”
- p 9, L 34-35: “therefore not meet”
- p 18, L 11: “The withdrawal”: should be, “The drawback”
- p 20, L 15: “which makes embedding of OBLIMAP low intrusive” and “The embed strategy”

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ED: Publish subject to technical corrections (14 Oct 2016) by Jeremy Fyke

AR by Thomas Reerink on behalf of the Authors (29 Oct 2016) Manuscript

Short summary

Ice sheets are part of the climate system and interact with the atmosphere and the ocean. OBLIMAP is a powerful tool to map climate fields between GCMs and ISMs (ice sheet models), which run on grids that differ in curvature, resolution and extent. OBLIMAP uses optimal aligned oblique projections, which minimize area distortions. OBLIMAP 2.0 allows for high-frequency embedded coupling and masked mapping. A fast search strategy realizes a huge performance gain and enables high-resolution mapping.