Aerosol Optical Properties and Long-Term Variations over the Northeastern Tibetan Plateau: Insights from Ground and Space Observations and MERRA-2 Data

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

General Comments

This article aims to characterize the fundamental aerosol optical properties over the northeastern Tibetan Plateau with ground-based sunphotometer observations of AOD. The results provide valuable localized insights for this specific region of the Tibetan Plateau, and expand ideas for in-depth research on the optical properties of high-altitude aerosols. I would recommend pubulishing the article in RS after the following aspects can be improved.

Specific Comments

1. In Figure S3 of the Supplementary Information, the relationship between AOD and AE appears to be non-linear. The current linear regression may not accurately reflect the underlying physical correlation. From the perspective of data relationships, the power-law fitting method may be more suitable for expressing the trend.

2. Regarding the diurnal evolution of the extinction profiles presented in Figure 4, providing only three discrete time intervals is insufficient to clearly illustrate the continuous dynamics of the aerosol vertical distribution. To better substantiate your conclusions, more extinction profiles should be added to reflect the development trend of boundary layer height and the relationship between boundary layer height and extinction profile distribution.

3. The textual annotations within Figure 5 and Figure 8 appear excessively crowded, which significantly hinders readability. Adjust the font sizes and line spacing to ensure that the descriptions are clear and legible.

4.  Regarding the calculated annual change rates for both AOD and AE in Line 482 and 491, it is essential that the author provide the corresponding p-values or confidence intervals to verify the statistical significance of the observed trends. Please ensure that the significance level is clearly stated in both the text and the relevant tables/figures.

5.The authors should ensure the standardized and consistent use of abbreviations throughout the manuscript. For instance, 'dust aerosols (DU)' is already defined as an acronym, yet the full term repeatedly appears in the subsequent text (e.g., Line 421, 522). Please conduct a thorough review of all abbreviations (e.g., AOD, AE) to maintain terminological consistency.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presents a useful analysis of aerosol optical properties, vertical extinction structure, and long-term variations over the Tibetan Plateau using ground-based observations together with satellite and reanalysis products. The study is generally well organized, and the topic is relevant. In particular, the combination of sunphotometer observations, LiDAR profiles, MODIS validation, and MERRA-2 analysis gives the paper some novelty. Overall, I think the manuscript has publication potential, but several minor issues should be addressed before acceptance.

 

Specific comments:

 

1. The title does not fully reflect the datasets actually used in the study. In addition to reanalysis data, the manuscript also uses LiDAR and MODIS data, but these are not mentioned in the title. I suggest revising the title so that it better matches the scope of the study.
2. The spatial description is not fully consistent throughout the manuscript. For example, the abstract and highlights emphasize the northeastern Tibetan Plateau, whereas the title refers more broadly to the Tibetan Plateau. The geographic scope should be stated consistently in the title, abstract, introduction, and main text.
3. In the Study Area section, the manuscript mentions the G6 Expressway, but this feature is not shown in Figure 1. I recommend marking it on the figure. In addition, the location of the Yellow River is not very clear in the current version of Figure 1 and could be made more visible. If possible, a small inset showing the observational site or instrument setup would also improve the presentation.
4. I am not sure that Reference [23] is the most appropriate citation for the geographic description in the Study Area section. Please check whether this reference is necessary or whether a more suitable source should be cited instead.
5. In line 162, “Where” should begin with a lowercase letter (“where”).
6. The text in lines 162–177 is repetitive. The explanation of τa(λ), α, β, and the interpolation of AOD at 550 nm is stated twice. This part should be merged and streamlined.
7. In line 214, the phrase “primarily targeting bright surfaces with low reflectivity” appears inaccurate. In general, bright surfaces are associated with relatively high reflectivity. Please revise this description for correctness.
8. In line 260, “Where” should also be changed to lowercase (“where”).
9. The section title “3. Result and Discussion” should be revised to “3. Results and Discussion” for standard academic usage.
10. In Section 3.1, the comparison with observations from many other sites seems somewhat peripheral to the main focus of this paper. Since the manuscript already contains substantial results, this part could be shortened or removed, or at least reduced to only the most relevant comparisons.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

This interesting paper presents a solid analysis of aerosol optical properties over the Tibetan Plateau. The authors provide a thorough assessment of the accuracy of satellite measurements through an intercomparison of different algorithms and data sources. Finaly, using the most reliable satellite data, the authors propose an analysis of aerosols trend over the last 20 years.

The paper can be published providing that the following minor comments are addressed:

These results were obtained for 2023 only. The authors should explain how these measurements are representative of average condition, or how they account for annual variability. In addition, it is unfortunate that no data are available from September to December. I suggest adding “for year 2023” somewhere in the title

Line 73: Please use the same unit (m or km) as in line 53 for elevation.

Lines 169-170: Something seem to be missing between these two lines.

Lones 543-545: The white solid line and the red dots are not easy to distinguish in the figure.

Author Response

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Author Response File: Author Response.docx