Atmospheric influences on the anomalous 2016 Antarctic sea ice decay

Schlosser, Elisabeth; Haumann, F. Alexander; Raphael, Marilyn N.

doi:https://doi.org/10.5194/tc-12-1103-2018

Articles | Volume 12, issue 3

https://doi.org/10.5194/tc-12-1103-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/tc-12-1103-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 12, issue 3

Research article

|

28 Mar 2018

Research article |

| 28 Mar 2018

Atmospheric influences on the anomalous 2016 Antarctic sea ice decay

Elisabeth Schlosser, F. Alexander Haumann, and Marilyn N. Raphael

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Final revised paper (published on 28 Mar 2018)
Preprint (discussion started on 22 Sep 2017)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review', Anonymous Referee #1, 06 Nov 2017
- AC1: 'preliminary response to Ref.#1 (by E. Schlosser)', Elisabeth Schlosser, 06 Nov 2017
- AC3: 'Final response to Referee #1', Elisabeth Schlosser, 01 Dec 2017
SC1: 'Peer Review', Sarah Cross, 29 Nov 2017
- AC2: 'Response to Ref. #2, Sarah Cross', Elisabeth Schlosser, 29 Nov 2017
AC2: 'Response to Ref. #2, Sarah Cross', Elisabeth Schlosser, 29 Nov 2017
AC3: 'Final response to Referee #1', Elisabeth Schlosser, 01 Dec 2017
RC2: 'Review', Anonymous Referee #2, 05 Dec 2017
- AC4: 'Final response to Referee #2', Alexander Haumann, 03 Jan 2018
AC4: 'Final response to Referee #2', Alexander Haumann, 03 Jan 2018

Peer-review completion

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

AR by Alexander Haumann on behalf of the Authors (06 Jan 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (16 Jan 2018) by Becky Alexander

RR by Anonymous Referee #2 (25 Jan 2018)

Suggestions for revision or reasons for rejection

Review on revised manuscript "Atmospheric influences on the anomalous 2016 Antarctic sea ice decay" by Elisabeth Schlosser, F. Alexander Haumann, and Marilyn N. Raphael.

General Comments
I thank the authors for their hard work revising the manuscript. I feel the manuscript is much improved and reads better. The analysis of heat fluxes is a nice addition and it strengthens the analysis that was previously shown qualitatively with arrows. One major comment I still have is the authors' interchangeable use of heat flux and heat advection. These are two different things and heat fluxes do not imply heat advection. Furthermore, using vertically integrated heat fluxes further complicates matters as it reflects many heat distribution processes occurring at various heights and does not isolate the low level processes influencing the sea ice. The authors need to acknowledge this and change the text accordingly, or better yet, examine advection to confirm their current analysis.

Specific Comments
Line 192: Heat flux is not the same as heat advection, which you use interchangeably. Please see comment below for more details.

Lines 296-300: This sentence requires a citation. And northerly/southerly flow does not always lead to advection as it depends on the presence of temperature gradients. While I appreciate your new analysis of vertically integrated northward heat flux, this is not the same and cannot be treated the same as advection for two important reasons. First, heat flux is essentially showing covariance between meridional wind and temperature, it does not show how meridional wind is modifying temperature. For the latter, you would need to actually calculate advection, e.g. -v ∂T/∂y . Second, by using vertical integration, you are not able to isolate heat advection at the surface, which would ultimately be important for the sea ice, as you are seeing a combination of advection and baroclinity at low levels along with eddies tied to jet behavior at upper levels. Therefore, vertically integrated heat fluxes do not tell you much about how the wind is actually influencing the sea ice with regards to heat transfer. To state that thermal advection is observed, you need to actually show advection. Either examine advection or reword the manuscript acknowledging these shortcomings. I think surface or low level (i.e. ~925 hPa) advection could be a worthwhile addition to the manuscript, or at least worth comparing with the heat fluxes to assure the reader there is indeed advection.

Lines 229-230: "True to its name"? Please reword this. The ASL naturally migrates in position, so please just state where it is located, e.g. "the ASL is located…".

Technical Corrections
Line 288: Eastern Weddell Sea is already defined so no need to define again.

Line 306: Please just call "Amundsen Sea Low" to be consistent with current literature.

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ED: Publish subject to technical corrections (26 Feb 2018) by Becky Alexander

AR by Elisabeth Schlosser on behalf of the Authors (02 Mar 2018) Manuscript

Short summary

The atmospheric influence on the unusually early and strong decrease in Antarctic sea ice in the austral spring 2016 was investigated using data from the global forecast model of the European Centre for Medium-range Weather Forecasts. Weather situations related to warm, northerly flow conditions in the regions with large negative anomalies in sea ice extent and area were frequent and explain to a large part the observed melting. Additionally, oceanic influences might play a role.