Systematic bias in evaluating chemical transport models with maximum daily 8&thinsp;h average (MDA8) surface ozone for air quality applications: a case study with GEOS-Chem v9.02

Travis, Katherine R.; Jacob, Daniel J.

doi:https://doi.org/10.5194/gmd-12-3641-2019

Articles | Volume 12, issue 8

https://doi.org/10.5194/gmd-12-3641-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/gmd-12-3641-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 12, issue 8

Methods for assessment of models

|

22 Aug 2019

Methods for assessment of models |

| 22 Aug 2019

Systematic bias in evaluating chemical transport models with maximum daily 8 h average (MDA8) surface ozone for air quality applications: a case study with GEOS-Chem v9.02

Katherine R. Travis and Daniel J. Jacob

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Final revised paper (published on 22 Aug 2019)
Preprint (discussion started on 04 Apr 2019)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'A concise analysis of ozone air quality model biases', Anonymous Referee #1, 14 Apr 2019
SC1: 'Executive Editor Comment on gmd-2019-60', Astrid Kerkweg, 24 Apr 2019
RC2: 'review of gmd-2019-78', Anonymous Referee #2, 29 Apr 2019
RC3: 'review of gmd-2019-78', Anonymous Referee #3, 12 Jun 2019
AC1: 'Author response to reviewer comment', Katherine Travis, 28 Jun 2019

Peer-review completion

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

AR by Katherine Travis on behalf of the Authors (28 Jun 2019) Author's response Manuscript

ED: Publish subject to minor revisions (review by editor) (17 Jul 2019) by Christoph Knote

Dear authors,

thank you very much for your revised submission. I think you have sufficiently answered the reviewers concerns. Reviewer 2 actually suggested to reject your manuscript. I will briefly comment on his/her concerns, which were threefold:

* application of the analysis to a very limited dataset and using only one model
I think the authors make sufficiently clear now that it is a case study with one model.

* lacking additional checks to confirm their conjectures
Section 5 put forward multiple reasons (deposition velocity calculation, stratification, ...) for a lack of agreement with the observations, and they are discussed appropriately. Lacking robustness is mended by the fact that the authors now clearly present the "case study" type of this work. I agree with the reviewer that additional simulations to confirm their conjectures might be of interest, but it is my concern that changes to deposition velocities "by eye" as sensitivity study will actually lead to a lot of changes (including changes in O3 formation in other places which are then advected etc.), and the results might not really be helpful.

* lacking robustness
As the reviewer him/herself states - issues like insufficient capture of PBL diurnal cycle by models are known and have broad applicability, hence they also apply to other models. It is my point of view that the authors make the distinction between their case study with GEOS-Chem and general suggestions for the broader modelling community clear, and that these results are actually applicable to other models as well.

After considering the arguments put forward by reviewer 2, and in light of the other two, favourable reviews I decided to allow this manuscript for publication.

One issue still remains before it can be published, though: neither a Dropbox nor a GitHub repository are acceptable solutions for archiving source code, input data and model output. Please read and comply with the GMD code and data policy (https://www.geoscientific-model-development.net/about/code_and_data_policy.html).

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AR by Katherine Travis on behalf of the Authors (19 Jul 2019) Author's response Manuscript

ED: Publish as is (22 Jul 2019) by Christoph Knote

AR by Katherine Travis on behalf of the Authors (22 Jul 2019) Manuscript

Short summary

Models of ozone air pollution are often evaluated with the policy metric set by the EPA of the maximum daily 8 h average ozone concentration. These models may be used in policy settings to evaluate air quality regulations. However, most models have difficulty simulating how ozone varies over the course of the day, and thus the use of this metric in model evaluation is problematic. Improved representation of mixed layer dynamics and ozone loss to the surface is needed to resolve this issue.