On the emissions and transport of bromoform: sensitivity to model resolution and emission location

Russo, M. R.; Ashfold, M. J.; Harris, N. R. P.; Pyle, J. A.

doi:https://doi.org/10.5194/acp-15-14031-2015

Articles | Volume 15, issue 24

https://doi.org/10.5194/acp-15-14031-2015

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

https://doi.org/10.5194/acp-15-14031-2015

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

Articles | Volume 15, issue 24

Research article

|

21 Dec 2015

Research article |

| 21 Dec 2015

On the emissions and transport of bromoform: sensitivity to model resolution and emission location

M. R. Russo, M. J. Ashfold, N. R. P. Harris, and J. A. Pyle

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Final revised paper (published on 21 Dec 2015)
Preprint (discussion started on 31 Jul 2015)

Interactive discussion

Status: closed

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

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- Supplement

RC C6463: 'Review for acp-2015-442', Anonymous Referee #1, 31 Aug 2015
- AC C8934: 'Reply to reviewer 1', Neil Harris, 04 Nov 2015
RC C6739: 'Review of ACP-2015-442', Anonymous Referee #2, 10 Sep 2015
- AC C8935: 'Reply to referee 2', Neil Harris, 04 Nov 2015

Peer-review completion

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

AR by Neil Harris on behalf of the Authors (08 Nov 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (10 Nov 2015) by Rolf Müller

RR by Anonymous Referee #2 (12 Nov 2015)

Suggestions for revision or reasons for rejection

The revision is an improvement over the original manuscript and is close to being publishable.

The authors like to stay with geometrical height as vertical coordinate. Although I still think that other coordinates like pressure or in particular potential temperature are physically more meaningful and may give more insight into the transport characteristics, the authors argument can be accepted.

A paragraph introducing the important features of the TTL has been added as well as a better description of the vertical coordinate of the model.

Furthermore a small comment regarding the small peak in 5 km height in several vertical profiles has been added assigning this feature to low level convection.

As a method to distinguish between extra-tropical and tropical emissions and to quantify their contributions to the bromoform mixing ratio in the TTL separate tracers have been used. The authors quantify the extra-tropical contribution as being roughly 10 percent and offer to include this information in the manuscript. To my mind this should be done.

In Figures 3d and 5d the maximum value of the bromoform tracer can not be derived from the plot. I did ask this question in my first review since the maximum values for bromoform in the lower TTL above the maritime continent in the high resolution run seem quite high to me if compared to the values given in the literature, e. g. the WMO Ozone Assessment 2014. Since these values strongly depend on the emissions in the marine boundary layer, I think it would be quite valuable to know if the surface values are above or below the maximum values of 4 ppt given in the the WMO report. Maybe the authors can think of a possibility to get access to the data they used for these plots.

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RR by Anonymous Referee #1 (17 Nov 2015)

ED: Reconsider after minor revisions (Editor review) (20 Nov 2015) by Rolf Müller

AR by Neil Harris on behalf of the Authors (03 Dec 2015) Author's response

ED: Publish as is (04 Dec 2015) by Rolf Müller

AR by Neil Harris on behalf of the Authors (10 Dec 2015)

Short summary

We find a strong regional element to the uplift of CHBr3 from the ocean to the upper troposphere and lower stratosphere. The strongest uplift occurs when the largest emission and the most intense convection are co-located which is over the Maritime Continent in northern winter. Estimates of CHBr3 emissions based on aircraft measurements will be sensitive to where the available aircraft campaigns took place.