Concentration Trajectory Route of Air pollution with an Integrated Lagrangian model (C-TRAIL Model v1.0) derived from the Community Multiscale Air Quality Model (CMAQ Model v5.2)

Pouyaei, Arman; Choi, Yunsoo; Jung, Jia; Sadeghi, Bavand; Song, Chul Han

doi:https://doi.org/10.5194/gmd-13-3489-2020

Articles | Volume 13, issue 8

https://doi.org/10.5194/gmd-13-3489-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/gmd-13-3489-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 13, issue 8

Model evaluation paper

|

05 Aug 2020

Model evaluation paper |

| 05 Aug 2020

Concentration Trajectory Route of Air pollution with an Integrated Lagrangian model (C-TRAIL Model v1.0) derived from the Community Multiscale Air Quality Model (CMAQ Model v5.2)

Arman Pouyaei, Yunsoo Choi, Jia Jung, Bavand Sadeghi, and Chul Han Song

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Final revised paper (published on 05 Aug 2020)
Supplement to the final revised paper
Preprint (discussion started on 24 Jan 2020)
Supplement to the preprint

Interactive discussion

Status: closed

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

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RC1: 'Review of "Concentration Trajectory Route of Air pollution with an Integrated Lagrangian model (C-TRAIL model v1.0) derived from the Community Multiscale Air Quality Modeling (CMAQ model v5.2)"', Anonymous Referee #1, 03 Mar 2020
- AC1: 'response_reviewer #1', Yunsoo Choi, 18 Apr 2020
RC2: 'Review of "Concentration Trajectory Route of Air pollution with an Integrated Lagrangian model (C-TRAIL model v1.0) derived from the Community Multiscale Air Quality Modeling (CMAQ model v5.2)', Anonymous Referee #2, 19 Mar 2020
- AC2: 'response_reviewer #2', Yunsoo Choi, 18 Apr 2020
- AC3: 'response_reviewer #2', Yunsoo Choi, 18 Apr 2020

Peer-review completion

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

AR by Yunsoo Choi on behalf of the Authors (18 Apr 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (24 Apr 2020) by Volker Grewe

RR by Anonymous Referee #1 (05 May 2020)

Suggestions for revision or reasons for rejection

I thank the authors for their responses to my comments. However, some issues remain. I have limited myself to issues which came up during my own prior review. I believe that this manuscript can in principle be published, but that some claims made in the paper still need to be moderated, and some additional details provided.

While I agree that C-TRAIL seems like a useful tool and look forward to seeing it applied more broadly, there does not seem to be sufficient quantitative evidence for claims in the abstract and elsewhere that the model can be called “reliable” and “comprehensive”. A true assessment of reliability would require comparison of C-TRAIL to results from other models for many different scenarios, rather than a single campaign. Furthermore, C-TRAIL has its own issues, including mass conservation errors and the (ubiquitous) uncertainty in meteorology and emissions inventories. I would recommend that the authors remove words like “reliable”, and “comprehensive” from the abstract, as these claims are not meaningfully quantified in the paper.

On a similar note, it seems too strong to claim that any model is “ideal” (line 342).

The conclusions still state that C-TRAIL is highly computationally efficient (line 348), but this is not quantified in the manuscript. Either this claim should be removed or a quantitative assessment of computational overhead due to C-TRAIL should be included.

The authors have added a description of air “packets”, which helps considerably. However, it would be useful to clarify that the packets are massless (if they are, as I assume). If they are not massless, then the question remains of how they can be pruned and spawned without incurring additional errors in mass conservation, beyond the “interpolation” errors already discussed by the authors. If they are indeed massless, then they also presumably have no size, rather than being simply small (lines 80-82).

I appreciated the authors' response regarding issues modeling cloud convection. However, this hinges on the approach taken by WRF and CMAQ for simulating convection, as well as the resolution of the original WRF simulation. It would be helpful to the reader if the authors included a technical description of how each of the three components (WRF, CMAQ, and C-TRAIL) attempts to account for convection. This would help both in understanding limitations of the approach and in ensuring that readers can reproduce the results.

There remain some grammatical errors, which unfortunately harm the readability of the paper. For example, line 125 reads “it incurs mass conservation by adding minor interpolation errors”, but this doesn’t make sense (I assume this was meant to be “it violates mass conservation” or “it incurs mass conservation errors”?). I recommend that authors perform an additional sweep for such issues, as well as fixing some of the figure references which appeared as “Error! Reference source not found”.

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ED: Publish subject to minor revisions (review by editor) (11 May 2020) by Volker Grewe

AR by Yunsoo Choi on behalf of the Authors (18 May 2020) Author's response Manuscript

ED: Publish subject to minor revisions (review by editor) (08 Jun 2020) by Volker Grewe

AR by Yunsoo Choi on behalf of the Authors (10 Jun 2020) Author's response Manuscript

ED: Publish as is (03 Jul 2020) by Volker Grewe

AR by Yunsoo Choi on behalf of the Authors (06 Jul 2020)

Short summary

This paper introduces a novel Lagrangian model (Concentration Trajectory of Air pollution with an Integrated Lagrangian model, C-TRAIL) for showing the source and receptor areas by following polluted air masses. To investigate the concentrations and trajectories of air masses simultaneously, we use the trajectory-grid (TG) Lagrangian advection model. The TG model follows the concentrations of representative air packets of species along trajectories determined by the wind field.