Review Reports - Set-Up of an Italian MAX-DOAS Measurement Network for Air-Quality Studies and Satellite Validation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper largely focuses on presenting the new sites and the results.
I suggest that the authors emphasize in the manuscript—especially in the abstract and in the conclusions—what the scientific novelty of the work is, i.e., what it adds that is new compared with previous studies. The authors have several earlier papers using the same instruments, and the novelty should also be clarified relative to other FRM4DOAS studies.
In the Results and Discussion section, it should be clear what is new in comparison with other similar works.
In the section “Examples of retrieved NO2 profiles and tropospheric VCD,” more details should be added, including how effective the cloud-screening method is and/or how it has been validated.
The bibliography is insufficient.

Author Response

We would like to express our sincere gratitude to the reviewer for the time and effort he/she dedicated to evaluating our manuscript. His/Her constructive comments have significantly improved the quality, clarity, and completeness of our work. We greatly appreciate their careful reading and valuable suggestions.

In the revised version of the manuscript the changes we made following a reviewer’s comment are reported in blue. Our replies are reported in blue below the reviewer’s comment.

The replies are attached

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In the validation of remote sensing products, continuous observation data from ground-based station networks serve as an important data source for algorithm and product verification. The authors comprehensively analyzed the basic information and result cases of the Italian MAX-DOAS observation network. The paper is well-substantiated, with credible results and validation processes, making it an excellent research work.

However, I have some questions that need clarification from the authors:

Regarding the introduction of the four stations (with a more detailed description of the RTV station), more information could be provided about the surrounding environment of the stations and the factors affecting the observation angles. This would facilitate readers in evaluating the impact of the surrounding environment on the stations.
When verifying the impact of done at the CMN station, the scientific validity is insufficient in comparing the observations at 11:30 (with done removed) with those at adjacent times. This is because NO₂ concentrations are unstable throughout the day, making it impossible to determine the exact cause of the differences between the measurement at 11:30 and the results at other times.
The authors mentioned that RTV is the reference instrument. Why are the data from the CMN station not compared with the observation data from RTV in Figure 4?
In the comparative validation between RTV and SPC, why are there no results for the UN channel?
It is recommended that the ordinate of the right panel in Figure 7 be modified to NO₂ VCDs.
In the validation against TROPOMI results, why are the satellite results presented as rectangles with identical color scales?

Author Response

In the revised version of the manuscript the changes we made following a reviewer’s comment are reported in blue. Our replies are reported in blue below the reviewer’s comment.

The replies are attached

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Please find attached comments and suggestions for authors.

Comments for author File: Comments.pdf

Author Response

In the revised version of the manuscript the changes we made following a reviewer’s comment are reported in blue. Our replies are reported in blue below the reviewer’s comment.

The replies are attached

Author Response File: Author Response.pdf