Bromine, iodine and sodium in surface snow along the 2013 Talos Dome–GV7 traverse (northern Victoria Land, East Antarctica)

Maffezzoli, Niccolò; Spolaor, Andrea; Barbante, Carlo; Bertò, Michele; Frezzotti, Massimo; Vallelonga, Paul

doi:https://doi.org/10.5194/tc-11-693-2017

Articles | Volume 11, issue 2

https://doi.org/10.5194/tc-11-693-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/tc-11-693-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 11, issue 2

Research article

|

17 Mar 2017

Research article |

| 17 Mar 2017

Bromine, iodine and sodium in surface snow along the 2013 Talos Dome–GV7 traverse (northern Victoria Land, East Antarctica)

Niccolò Maffezzoli, Andrea Spolaor, Carlo Barbante, Michele Bertò, Massimo Frezzotti, and Paul Vallelonga

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Final revised paper (published on 17 Mar 2017)
Supplement to the final revised paper
Preprint (discussion started on 17 Oct 2016)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review of Maffezzoli et al', Anonymous Referee #1, 23 Nov 2016
- AC1: 'Answer to Referee#1', Niccolò Maffezzoli, 10 Jan 2017
RC2: 'Referee comment', Anonymous Referee #2, 08 Dec 2016
- AC2: 'Answer to Referee#2', Niccolò Maffezzoli, 10 Jan 2017
RC3: 'Review comment', Anonymous Referee #3, 11 Dec 2016
- AC3: 'Answer to Referee#3', Niccolò Maffezzoli, 10 Jan 2017

Peer-review completion

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

AR by Niccolò Maffezzoli on behalf of the Authors (17 Jan 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (22 Jan 2017) by Joel Savarino

RR by Legrand Michel (04 Feb 2017)

RR by Anonymous Referee #2 (07 Feb 2017)

Suggestions for revision or reasons for rejection

The manuscript is much improved compared to the initial submission. I recommend publication following some minor corrections outlined here.

Line 15 amend to: “Halogen chemistry in the polar regions occurs through the release of halogens from sea salt aerosol…”

Line 16 amend to: “saline condensed phases associated with sea ice surfaces…”

Line 17 and 18 amend to: “Measurements of halogen species in polar snow samples are limited to a few sites and there is some evidence that they are related to sea ice extent.”

Line 48 amend to: “leading to formation of bromine monoxide, BrO, through reaction with ozone:”

Lines 56 to 58: The Schoenhardt et al 2012 paper cited does not report tropospheric vertical columns, but total columns. Either amend the statement or find a different reference (although I am not aware that anyone has derived tropospheric columns for IO).

Line 221: amend to 0.0062

Line 230: this is not the dominant sink of Br/source of HBr. Reaction with HCHO has the same rate constant, but HCHO will be present at much higher concentrations than HO2. Actually you don’t need to include the reaction at all.

Line 243: there is some confusion here. The statement that this parameter (bromine enrichment) is a marker of sea salt aerosol is contrary to what is written in Line 232, which talks of depletion being associated with sea salt aerosol.

Line 247 amend to: “they are also observed in winter, e.g. in core 8” – there are several examples, and core 8 is just one.

Line 253 amend to: “high winter singularities or more extended peaks in cores GV7 and 8 respectively”

Line 257 amend to: “by multiplying the sea ice concentration”

Line 273 amend to “with maximum in November”

Line 274: While it’s intuitive to think that the combination of sea ice and solar irradiance will generate the seasonality of bromine enrichment, the statement of line 274 “Such comparison suggests that the combined effect of sea ice and insolation drives the seasonality of bromine enrichment” is overstated when looking at Figure 7b. To look at just one example, bromine enrichment in October and November are effectively equal, while %SR.SI are considerably different. The authors need to be clear about the caveats when drawing their conclusions. A better way to present this would be “The combined effect of sea ice and insolation (Fig. 7b, magenta product distribution) shows similar features, with maximum in November, albeit with a much more pronounced springtime increase than seen in the bromine enrichment.” I don’t think that the statement about sea ice and insolation driving the seasonality of bromine enrichment can be supported by the data. One could find other factors with the same seasonality. For example, the seasonality of short-wave uv radiation alone (~300 nm) gives a November maximum (because of the effect of the ozone hole), so one could equally attribute that to driving seasonality of bromine enrichment.

Line 317 amend to: “consistent with the homogeneous…”

Line 333 again the authors are over-stating what can be drawn from their data. I’d suggest amending to “consistent with a sea ice influence in the area for the extra bromine deposition”.

Lines 335 and 336: in line with my comments above I’d suggest softening the statement to “There is some evidence that the seasonality is linked to the combined effect of sea ice growth and sunlight, which trigger photochemistry above fresh sea ice”

Figure 9 is poor quality (somehow low resolution) and needs to be improved before publishing.

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ED: Publish subject to minor revisions (Editor review) (07 Feb 2017) by Joel Savarino

AR by Niccolò Maffezzoli on behalf of the Authors (08 Feb 2017) Author's response Manuscript

ED: Publish as is (09 Feb 2017) by Joel Savarino

AR by Niccolò Maffezzoli on behalf of the Authors (11 Feb 2017) Author's response Manuscript

Short summary

Sea ice is a crucial parameter within Earth's climate system. Understanding its dynamics and its response to other climatic variables is therefore of primary importance in view of a warming climate and sea ice decline. In this work we investigate some features of a chemical parameter in ice cores, bromine enrichment, which is linked to sea ice and can therefore be used to reconstruct sea ice in the past.