Comparison of ERA5 and ERA-Interim near-surface air temperature, snowfall and precipitation over Arctic sea ice: effects on sea ice thermodynamics and evolution

Wang, Caixin; Graham, Robert M.; Wang, Keguang; Gerland, Sebastian; Granskog, Mats A.

doi:https://doi.org/10.5194/tc-13-1661-2019

Articles | Volume 13, issue 6

https://doi.org/10.5194/tc-13-1661-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/tc-13-1661-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 13, issue 6

Research article

|

14 Jun 2019

Research article |

| 14 Jun 2019

Comparison of ERA5 and ERA-Interim near-surface air temperature, snowfall and precipitation over Arctic sea ice: effects on sea ice thermodynamics and evolution

Caixin Wang, Robert M. Graham, Keguang Wang, Sebastian Gerland, and Mats A. Granskog

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Final revised paper (published on 14 Jun 2019)
Supplement to the final revised paper
Preprint (discussion started on 07 Dec 2018)

Interactive discussion

Status: closed

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

- Printer-friendly version

- Supplement

RC1: 'Review of Wang et al.', Anonymous Referee #1, 04 Jan 2019
- AC3: 'Response to Anonymous Referee # 1', Caixin Wang, 01 Mar 2019
RC2: 'Review of “Comparison of ERA5 and ERA-Interim near surface air temperature and precipitation over Arctic sea ice: Effects on sea ice thermodynamics and evolution” by Wang et al', Alek Petty, 15 Jan 2019
- AC2: 'Response to Referee Alek Petty', Caixin Wang, 01 Mar 2019
AC1: 'Supplementary Information', Caixin Wang, 01 Mar 2019

Peer-review completion

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

AR by Caixin Wang on behalf of the Authors (01 Mar 2019)

ED: Referee Nomination & Report Request started (13 Mar 2019) by Chris Derksen

RR by Anonymous Referee #1 (28 Mar 2019)

RR by Alek Petty (05 Apr 2019)

Suggestions for revision or reasons for rejection

Most importantly, I recently had a look at the ERA5 snowfall and my brief analysis suggested it’s pretty consistently higher than ERA-I snowfall over the Arctic in all seasons, which isn’t what you find in this paper. I think it’s worth you (and me!) taking a closer look at your ERAI and ERA5 snowfall results. Perhaps the time period matters here, but there was some difference with the data from ERAI to ERA5 (summing hourly ERA5 values within a day instead of 6-hourly ERA-I data). This needs to be resolved and could have a significant impact on your results that would need correcting if I am right.

Other comments:

I still think you need to make clearer the changing ratio of snowfall to precip as it seems a big part of the story and not beyond the scope of this work at all.

New Figure 2: Drop the colorbars in the first three columns as they are the same as the colorbar on the right. Add the variable (i.e. 2m air temperature (C)). Unclear what you’ve done with the ice extent as I can’t make it out on the maps.

New Figures 3 and 4: thanks for making this change, I think it’s an improvement but I still think it could be better! It’s tough to jump between the figures and interpret the differences, and again I think the comparison to the buoys is more important so I would suggest merging these figures and just showing one or to buoy profiles instead in each figure. Can you place the Figure 4 buoy comparison panel between the raw and difference plots in Figure 3? It would also be nice to have RMSE values included here too for the buoy comparisons to ERAI and ERA5.

New Figure 6: nice!

New Figure 7: looks better! I would suggest dropping the second y-axis as this has the same units and just stating that in the left y labels (snow water equivalent (mm)) and make clear that you have cumulated reanalysis values and measured buoy snow depth values shown.

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ED: Publish subject to minor revisions (review by editor) (08 Apr 2019) by Chris Derksen

AR by Caixin Wang on behalf of the Authors (30 Apr 2019)

ED: Publish subject to minor revisions (review by editor) (06 May 2019) by Chris Derksen

ED: Reconsider after major revisions (06 May 2019) by Chris Derksen

AR by Caixin Wang on behalf of the Authors (07 May 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (08 May 2019) by Chris Derksen

RR by Alek Petty (16 May 2019)

RR by Anonymous Referee #1 (28 May 2019)

ED: Publish subject to technical corrections (29 May 2019) by Chris Derksen

AR by Caixin Wang on behalf of the Authors (31 May 2019) Author's response Manuscript

Short summary

A warm bias and higher total precipitation and snowfall were found in ERA5 compared with ERA-Interim (ERA-I) over Arctic sea ice. The warm bias in ERA5 was larger in the cold season when 2 m air temperature was < −25 °C and smaller in the warm season than in ERA-I. Substantial anomalous Arctic rainfall in ERA-I was reduced in ERA5, particularly in summer and autumn. When using ERA5 and ERA-I to force a 1-D sea ice model, the effects on ice growth are very small (cm) during the freezing period.