Oceanic bromoform emissions weighted by their ozone depletion potential

Tegtmeier, S.; Ziska, F.; Pisso, I.; Quack, B.; Velders, G. J. M.; Yang, X.; Krüger, K.

doi:https://doi.org/10.5194/acp-15-13647-2015

Articles | Volume 15, issue 23

https://doi.org/10.5194/acp-15-13647-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue:

The EU Project SHIVA (Stratospheric Ozone: Halogen Impacts...

https://doi.org/10.5194/acp-15-13647-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 15, issue 23

Research article

|

10 Dec 2015

Research article |

| 10 Dec 2015

Oceanic bromoform emissions weighted by their ozone depletion potential

S. Tegtmeier, F. Ziska, I. Pisso, B. Quack, G. J. M. Velders, X. Yang, and K. Krüger

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Final revised paper (published on 10 Dec 2015)
Supplement to the final revised paper
Preprint (discussion started on 26 May 2015)

Interactive discussion

Status: closed

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

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- Supplement

RC C5264: 'review', Anonymous Referee #1, 27 Jul 2015
- AC C7329: 'Reply to review 1', Susann Tegtmeier, 28 Sep 2015
RC C5349: 'Review of Tegtmeier et al.', Anonymous Referee #2, 29 Jul 2015
- AC C7330: 'Reply to review 2', Susann Tegtmeier, 28 Sep 2015

Peer-review completion

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

AR by Susann Tegtmeier on behalf of the Authors (28 Sep 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (14 Oct 2015) by Peter Haynes

RR by Anonymous Referee #1 (26 Oct 2015)

Suggestions for revision or reasons for rejection

Tegtmeier et al presents a quantitative estimate of the ozone depletion potential (ODP)-weighted emission calculation for the most abundant very-short-lived brominated compound, CHBr3. The revised manuscript has taken serious consideration of the comments given by the previous reviewers and has addressed several major concerns raised by the two reviewers. My comments are mainly editorial, but this likely is not a full list of needed corrections. I would recommend (i) the authors seek some editorial help from a native English speaker or the ACP editorial office; (ii) the manuscript is very long and can use some condensing.

Minor comments:

L61: “coupled to” -> due to

L69: 21 -> 21st

L83: troposphere-to-stratosphere transport

L86: “it remains … climate” -> the role of oceanic VSLS on stratospheric ozone in a future changing climate remains a challenge.

L92-95: Sounds awkward. Consider rephrasing.

L98-100: Change to “The resulted change in O3 leads to a contribution of -0.02 Wm-2 to global radiative forcing.

L105-106: troposphere-to-stratosphere transport

L119: delete “,” after anthropogenic

L126: Change to “As a consequence,”

L128: Delete “So far”

L140-141: Change to “will require weighting emissions and ODPs, both are highly variable”

L144: delete “the” before CHBr3

L145: add “,” after framework

L146: “allow to compare” -> comparison of

L208: Delete “by” before changes

L211: Delete “oceanic”

L218: You should probably cite Wuebbles et al. (1983) here.

L241: trajectories -> trajectory

L308-312: Change to “We expect changes in the stratospheric residence time only have small impact on the future ODP, compared to the impacts of tropospheric transport and stratospheric chemistry.

L423: Change “the ones of human-made” to “the manmade”

L427: Change to “less than 10% of the regions over the globe”

L432: “Already this lower boundary of the” -> Even the lower limit of the; delete “,” after emissions

L433: Delete “even”

L436: Delete “even”

L436-438: -> The CHBr3 emissions and ODP show similar latitudinal …

L439: causes -> leads to

L481: add “the” before strongest

L488: -> To analyze the future change of ODP-weighted CHBr3 emissions, we need to extend the times series beyond 2006.

L496: south-east -> Southeast

L511: south-east ward pointing -> southeastward

L556-558: Is the seasonal cycle mainly driven by seasonality in deep convection or emissions, or both?

L577: Delete “nevessarily”

L624: inner -> deep

L625: can reach locally higher values -> show higher local maxima

L633: delete “a” before similar

L643-644: reasonably well captured -> captured reasonably well

L644: encouraging -> lending confidence in
L698: Add “(5.4%)” after increase

L699-701: Delete the “If … simulations.” sentence.

L814: tropospheric transport -> troposphere-to-stratosphere transport

L818: 31% increase respect to what year?

Figure 3: HCFC-141 and HCFC-142 should be HCFC-141b and HCFC-142b

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RR by Anonymous Referee #2 (02 Nov 2015)

Suggestions for revision or reasons for rejection

Review ‘Oceanic bromoform emissions weighted by their ozone depletion potential’ by Tegtmeier et al.,

The authors have done a great job in tightening this manuscript and addressing all of my concerns raised in my first review. I only have minor comments and a clarification.

Clarification / Discussion point
The ODP-weighted CHBr3 emissions displayed in figure 9 show a maximum in the boreal summer when mass fluxes are weaker than the austral summer ODP mass-fluxes (figure 5c). This is due (and mentioned in the paper) to the very high emissions in SA Asia, that are lacking in the MC from Ziska, 2013. However, the seasonality of emissions in these regions is not taken into account (and observations in both regions are likely to be biased to certain seasons), so a stronger caveat in the interpretation of figure 9 would add to the discussion. While differing model results support this seasonality, meaning their meteorology and mass fluxes support each other, but I assume all runs were being driven by the same Ziska emission fields – so this is not surprising. It would be useful to produce a figure 9 curve with a different emission inventory to test the robustness of this seen seasonality in ODPs. A comment about this expected seasonality in stratospheric bromoform concentrations and the requirement that this UTLS bromoform seasonality needs to be verified by observations would also add to the discussion.

Minor Typos / Grammatical changes
Line 74 – ‘however evidence arises’ change to ‘however evidence has emerged’
Line 99 change to: Through the relatively large impact of VSLS on ozone in the lower stratosphere, VSLSs contribute -0.02 Wm-2 to global radiative forcing (~6% of the 0.33 Wm-2 from all ODS halocarbons) …
Line 106 compared change to relative
Line 120 measure change to metric
Line 125 change to only a fraction of the originally released VSLS reaches the…
Line 126 change ‘cannot be given’ as to ‘is not’
Line 140 will require change to requires
Line 144 remove will
Line 146 ‘will allow to compare’ change to ‘allows assessment of’
Line 155 change which takes to taking
Line 208 remove by after the
Line 210 add s to increase
Line 311 change cost-efficient to computationally-efficient
Line 687 change ‘global warming’ to ‘increased GHG induced tropospheric warming’ leading to
Line 745 change ‘a particular high’ to ‘particularly high’
Line 746 change from to due to
Line 751 change to lead to a two to three-fold increase in ODP-weighted …

Referee Report: PDF

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ED: Reconsider after minor revisions (Editor review) (09 Nov 2015) by Peter Haynes

AR by Anna Wenzel on behalf of the Authors (19 Nov 2015) Author's response Manuscript

ED: Publish subject to technical corrections (27 Nov 2015) by Peter Haynes

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Short summary

At present, man-made halogens and natural oceanic substances both contribute to the observed ozone depletion. Emissions of the anthropogenic halogens have been reduced, whereas emissions of the natural substances are expected to increase in future climate due to anthropogenic activities affecting oceanic processes. We assess the impact of these oceanic substances on ozone by weighting their emissions with their potential to destroy ozone for current conditions and future projections.