Analysis and Validation of the Aerosol Optical Depth of MODIS Products in Gansu Province, Northwest China

Round 1

Reviewer 1 Report

Revision Remote Sensing  2420690                                                   26 May 2023

Recommendations:

1- Fig  1- DEM - what is the meaning  of this over Fig 1.?

2-Line 163 – The period, April 2018 to December 2019, perhaps is a short period   for atmospheric studies. Explain that the period is suitable.

3-Line 164-166- Information about the number of data used should be included, clearly.

4-Line 164. Solar radiation should be direct, diffuse or global, what kind of solar radiation, for each channel, the manuscript used.

5-Line 166—It is written: “aerosol parameters etc” Manuscript should explain what are the variables include at “etc”

6-The expressions included from line 172 to 174, it is not clearly explained what data used the manuscript?

7-  Fig 2 shows a very small size of letters and numbers. Please try to increase them. The black points are clear.

8-Line 185- Angstrom A [44] is not written well in relation its symbols over two letters,    which do not appear, in this case. Please write them well.

9- Line 189- Ångström should be written according with some rules because it is a name of a person.

10- Line 496- Angstrom is not well written. Please introduce the corresponding accents. Please verified this along the manuscript.

11-Angstrom it is not properly written along the manuscript. Authors need to find the WORD symbols, and find a panel with different symbols and then you select what you need. According to this, it is easy to write this name of well. Please try to do.   

 

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The comments of "Analysis and Validation of the Aerosol Optical Depth of MODIS Products in Gansu Province, Northwest China", This article mainly discusses the adaptability of MODIS products in Gansu, China, and uses the aerosol optical thickness values of three stations in Gansu, Dunhuang, Minqin, Lanzhou, ground observation stations to compare with MODIS products, and the results show that (1) the correlation between the MODIS AOD products of the two algorithms and the ground-based observation data decreases with an increasing of spatial sampling window size. When the spatial sampling window of the two algorithms is set at 30 km×30 km, it is more representative of the AOD value in Gansu Province, thus reflecting local characteristics; (2) When the spatial sampling window is set at 30 km×30 km, the inversion effect of the DB algorithm AOD is better than that of the DB-DT-Combined algorithm AOD on different underlying surfaces;(3) The seasonal variability in the inversion accuracy of the DB algorithm AOD is less than that of the DB-DT-Combined algorithm, and it has inversion advantages in spring, autumn and winter, while the DB-DT-Combined algorithm outperforms the DB algorithm only in winter. The inversion effect of the two algorithms on AOD is influenced by the spatial sampling window setting; (4) Both the DB algorithm AOD and the DB-DT-Combined algorithm AOD can monitor the distribution of AOD in the central and western regions of Gansu, especially for high values of AOD under polluted atmospheric conditions, which represents a good monitoring effect. The research results of this paper have reference significance for the use of MODIS products in western China, and the language expression is good. It is suggested to accept this article after modification. The comments is as follows：The three stations used in this paper, Dunhuang, Minqin and Lanzhou, are far away from each other, and the vegetation in different areas is also affected by the surrounding environment. Will the influence of different ground-based station environment on these three stations affect the results of the evaluation of MODIS products?

Author Response

Please see the attachment.

Author Response File: Author Response.docx