Changes of the Arctic marginal ice zone during the satellite era

Rolph, Rebecca J.; Feltham, Daniel L.; Schröder, David

doi:https://doi.org/10.5194/tc-14-1971-2020

Articles | Volume 14, issue 6

https://doi.org/10.5194/tc-14-1971-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/tc-14-1971-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 14, issue 6

Research article

| Highlight paper

|

18 Jun 2020

Research article | Highlight paper |

| 18 Jun 2020

Changes of the Arctic marginal ice zone during the satellite era

Rebecca J. Rolph, Daniel L. Feltham, and David Schröder

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Final revised paper (published on 18 Jun 2020)
Preprint (discussion started on 08 Nov 2019)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'What is new here?', Anonymous Referee #1, 06 Dec 2019
- AC1: 'Response to Reviewer 1', Rebecca Rolph, 26 Mar 2020
RC2: 'Lack of trends is potentially interesting', Court Strong, 11 Dec 2019
- AC2: 'Author response to Court Strong', Rebecca Rolph, 26 Mar 2020
RC3: 'Review for "Changes of the Arctic marginal ice zone"', Anonymous Referee #3, 19 Dec 2019
- AC3: 'Response to Reviewer 3', Rebecca Rolph, 26 Mar 2020
- AC4: 'Figure 4. Sea ice area within the MIZ', Rebecca Rolph, 26 Mar 2020

Peer-review completion

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

ED: Reconsider after major revisions (further review by editor and referees) (02 Apr 2020) by John Yackel

AR by Rebecca Rolph on behalf of the Authors (03 Apr 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (12 Apr 2020) by John Yackel

RR by Court Strong (28 Apr 2020)

RR by Christopher Horvat (01 May 2020)

RR by Anonymous Referee #3 (05 May 2020)

Suggestions for revision or reasons for rejection

Review of revised manuscript, “Changes of the Arctic marginal ice zone during the satellite era” by Rebecca J. Rolph, Daniel L. Feltham, and David Schröder

General comments
The revised manuscript “Changes of the Arctic marginal ice zone during the satellite era” by R. Rolph, D. Feltham, and D. Schröder provides a comprehensive analysis of evolution in Arctic marginal ice zone (MIZ) extent relative to total sea ice extent (SIE) in a changing climate, and clearly addresses issues noted during the review process. Evaluation of MIZ width and latitude provide additional evidence for the absence of trends in MIZ extent, while investigation of MIZ area provides further characterization for changes in the MIZ based on the operational definition of the 15% - 80% sea ice concentration threshold. Thank you for a rigorous and quantitative analysis in response to questions raised. Please find below some additional comments and questions for consideration.

1. Thank you for the figure showing changes in MIZ area for the satellite record, and for including analysis and a discussion of MIZ area. Also of interest is the change in ice concentration distributions and heterogeneity within the MIZ; this could be evaluated by examining the time series for the ratio of MIZ extent to area. In particular, does the area analysis include an evaluation of the trends in the ratio, or a comparison of trends in MIZ extent and MIZ area separately?
Although the authors note in lines 337 – 343 of the revised manuscript “Since there is no trend in sea ice area within the MIZ and no trend in the MIZ extent, there is no significant change of sea ice concentration within the MIZ based on observations (where sea ice concentration in the MIZ is given as the ratio of the area of sea ice in the MIZ and the extent of the MIZ). Similarly, there would not be any trend of sea ice area within the MIZ relative to the MIZ 340 extent. Since there is also no observed change in MIZ extent, it follows that the pan-Arctic averaged sea ice concentration is not declining in concert with its declining extent. This suggests that changes to the extent of the MIZ depend strongly on the sea ice thickness distribution.”, it might also be helpful to present the figure for the time series of the MIZ extent to area ratio.

2. Although trends are considered for the 1979 – 2017 timeframe, what behaviour is observed for the MIZ property (extent, area, ratio of extent to area, latitude and width) anomalies relative to the 1981-2010 climatology? Anomalies, in addition to trends, might further illustrate changes in MIZ properties in recent years.

3. Line 31. Perhaps include the phrase “defined in this study according to the operational characterization” following MIZ.

4. Figure 2. Perhaps include names of months in titles, for consistency with other figures.

Thanks again for your responses and the opportunity to review the manuscript.

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ED: Publish as is (06 May 2020) by John Yackel

AR by Rebecca Rolph on behalf of the Authors (12 May 2020) Author's response Manuscript

Short summary

It is well known that the Arctic sea ice extent is declining, and it is often assumed that the marginal ice zone (MIZ), the area of partial sea ice cover, is consequently increasing. However, we find no trend in the MIZ extent during the last 40 years from observations that is consistent with a widening of the MIZ as it moves northward. Differences of MIZ extent between different satellite retrievals are too large to provide a robust basis to verify model simulations of MIZ extent.