The POLARCAT Model Intercomparison Project (POLMIP): overview and evaluation with observations

Emmons, L. K.; Arnold, S. R.; Monks, S. A.; Huijnen, V.; Tilmes, S.; Law, K. S.; Thomas, J. L.; Raut, J.-C.; Bouarar, I.; Turquety, S.; Long, Y.; Duncan, B.; Steenrod, S.; Strode, S.; Flemming, J.; Mao, J.; Langner, J.; Thompson, A. M.; Tarasick, D.; Apel, E. C.; Blake, D. R.; Cohen, R. C.; Dibb, J.; Diskin, G. S.; Fried, A.; Hall, S. R.; Huey, L. G.; Weinheimer, A. J.; Wisthaler, A.; Mikoviny, T.; Nowak, J.; Peischl, J.; Roberts, J. M.; Ryerson, T.; Warneke, C.; Helmig, D.

doi:https://doi.org/10.5194/acp-15-6721-2015

Articles | Volume 15, issue 12

https://doi.org/10.5194/acp-15-6721-2015

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

Special issue:

POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface...

https://doi.org/10.5194/acp-15-6721-2015

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

Articles | Volume 15, issue 12

Research article

|

17 Jun 2015

Research article |

| 17 Jun 2015

The POLARCAT Model Intercomparison Project (POLMIP): overview and evaluation with observations

L. K. Emmons, S. R. Arnold, S. A. Monks, V. Huijnen, S. Tilmes, K. S. Law, J. L. Thomas, J.-C. Raut, I. Bouarar, S. Turquety, Y. Long, B. Duncan, S. Steenrod, S. Strode, J. Flemming, J. Mao, J. Langner, A. M. Thompson, D. Tarasick, E. C. Apel, D. R. Blake, R. C. Cohen, J. Dibb, G. S. Diskin, A. Fried, S. R. Hall, L. G. Huey, A. J. Weinheimer, A. Wisthaler, T. Mikoviny, J. Nowak, J. Peischl, J. M. Roberts, T. Ryerson, C. Warneke, and D. Helmig

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Final revised paper (published on 17 Jun 2015)
Preprint (discussion started on 25 Nov 2014)

Interactive discussion

Status: closed

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

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RC C10766: 'Review of “The POLARCAT Model Intercomparison Project (POLMIP): overview and evaluation with observations” by Emmons et al.', Anonymous Referee #1, 04 Jan 2015
- AC C12712: 'Response to Referee #1', Louisa Emmons, 20 Mar 2015
RC C11302: 'Reviewer comment on Emmons et al. [2014]', Anonymous Referee #2, 18 Jan 2015
- AC C12713: 'Response to Referee #2', Louisa Emmons, 20 Mar 2015

Peer-review completion

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

AR by Louisa Emmons on behalf of the Authors (20 Mar 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (20 Apr 2015) by Michael Schulz

RR by Anonymous Referee #1 (05 May 2015)

RR by Anonymous Referee #2 (18 May 2015)

Suggestions for revision or reasons for rejection

The manuscript clearly presents the models which have been used in the POLARCAT model intercomparison (POLARMIP), characterizes some of the general behaviour of these models in the Arctic with useful analysis, and presents an extensive comparison with atmospheric composition observations made in the Arctic.

The paper has tried to disentangle the impact of uncertainties in emissions from characteristics in the models (chemical and physical parameterisations) in describing the composition of the Arctic atmosphere. It is suggested that by using the same emission data set, differences seen between model results can be easier interpreted and attributed to model differences or deficiencies. Also, when for certain species close to their principal emission regions a similar behaviour/deviation is seen among the models with respect to the observations, it allows (with some confidence) to pinpoint possible uncertainties/inaccuracies in the emission data set. On the other hand, when specific models compare remarkably well or bad with observations, the authors have tried to find out which processes might be responsible for this behaviour.

It is appreciated that the authors have done this effort of attributing differences with observations to specific model parameterizations or characteristics, although the statements are sometimes a bit vague and could have benefitted from some more underpinning. However, I think that attributing firmly the observed deficiencies to specific paramaterisations demands for a large amount of extra sensitivity simulations, which is probably outside the scope of this model intercomparison exercise. That is however possibly the way forward to characterize deficiencies in CTMs and improve their capability to describe well the Arctic atmospheric composition. It is assumed that the two additional POLARMIP papers of Arnold et al. [2014] and Monks et al. [2014] focus more on some specific model behaviour.

I appreciate the response of the authors in taking into account the comments on the former version of the manuscript.

Therefore, there are only some small technical comments listed below.

page 2, one but last line : add ":" after "***now".
page 6 : "VOC" used but defined only later (on page 9).
page 11, line 14-15 : "suggested by (Mao et al., 2013)" -> "suggested by Mao et al. (2013)".
page 17, line 10 : "carbon monoxide (CO)" : CO is already defined on page 6.
page 18, line 20 : "June-July" with a short "-", whereas most other appearances have a long "-".
page 20, line 9 : "June 18-July 15" with a short "-", whereas most other appearances have a long "-".
page 20, line 22, 23, 28 : "Figure" -> "Fig."
page 22, line 16 : "Figure" -> "Fig"
page 23, line 14 : "Figures" -> "Figs."
page 23, line 20 : "Figure" -> "Fig."
page 23, line 23 : "J" is once italic, and once straight.
page 24, line 20 : "ppb" has a larger font here than on all other places in the text.
Figs. 3 and 4 : Please add some extra values on the vertical axis.
page 57, caption : maybe change "France" -> "POLARCAT France"

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ED: Publish subject to technical corrections (27 May 2015) by Michael Schulz

AR by Louisa Emmons on behalf of the Authors (28 May 2015) Author's response Manuscript

Short summary

Eleven 3-D tropospheric chemistry models have been compared and evaluated with observations in the Arctic during the International Polar Year (IPY 2008). Large differences are seen among the models, particularly related to the model chemistry of volatile organic compounds (VOCs) and reactive nitrogen (NOx, PAN, HNO3) partitioning. Consistency among the models in the underestimation of CO, ethane and propane indicates the emission inventory is too low for these compounds.