Validation Analysis of Drought Monitoring Based on FY-4 Satellite

Round 1

Reviewer 1 Report

The paper should have a better separation of results and discussions, not least because in the discussions results are being presented. 

It would be important for the authors to discuss more the comparison with MODIS and justify the gain of using FY-4A in relation to MODIS or even data obtained from weather stations. 

It would be worth a paragraph physically explaining the differences in obtaining data with FY-4A compared to other satellites of older generations

An overall conclusion of the work is lacking.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Journal of applied sciences

Drought Monitoring Based on FY-4A Satellite Images

Dear Editor

This manuscript proposes a novel process of drought monitoring index calculation based on the high-frequency geostationary meteorological satellite FY-4A, and select the three representative drought events from 2021 to 2022 for validation.

This article is well written and structured. Also, all the points of essay writing have been well followed, and the results have been well expanded and explained. But the study does not enough innovation compared to previous relevant studies.

I recommend that this manuscript not be accepted without major revision.

 

Sincerely,

I here summarize these comments:

Comments:

1.     It is better to choose a more suitable title for the manuscript.

2.     Please, show the location of each region in China in the figure 1.

3.     Please explain more about the work innovation. Compared to the previous studies, the innovation is not very significant. If possible, a new idea can be added to improve the manuscript.

4.     Can these indices be calculated using other satellites such as Landsat and Sentinel? Adding results from other satellites and comparing with existing results can help improve the study.

5.     You can use these articles to get ideas in your manuscript.

·      https://doi.org/10.3390/su142013051

This manuscript proposes a novel process of drought monitoring index calculation based on the high-frequency geostationary meteorological satellite FY-4A, and select the three representative drought events from 2021 to 2022 for validation.

This article is well written and structured. Also, all the points of essay writing have been well followed, and the results have been well expanded and explained. But the study does not enough innovation compared to previous relevant studies.

I recommend that this manuscript not be accepted without major revision.

I here summarize these comments:

Comments:

1.     It is better to choose a more suitable title for the manuscript.

2.     Please, show the location of each region in China in the figure 1.

3.     Please explain more about the work innovation. Compared to the previous studies, the innovation is not very significant. If possible, a new idea can be added to improve the manuscript.

4.     Can these indices be calculated using other satellites such as Landsat and Sentinel? Adding results from other satellites and comparing with existing results can help improve the study.

5.     You can use these articles to get ideas in your manuscript.

·       Goodarzi, M., Fatehifar, A., and Avazpoor, F. (2019). "Bivariate analysis of the impact of climate change on drought with SPEI index and Coppola functions (Case study: Dugonbadan)." Iran-Water Resources Research, 15(4), 352-365.

. https://doi.org/10.3390/su142013051

·       https://doi.org/10.1016/j.coldregions.2022.103682

·       https://doi.org/10.3390/w15091650

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

In this research, FY-4A geostationary meteorological satellite images were used instead of MODIS to prepare the drought map. The TVDI index is the basis of the work and has been evaluated in three study areas with other indices such as SRHI and MCI. The authors claim that the satellite and the index used have more accurate results than MODIS and the indices obtained from it. In general, the writing of the article is scientific and good, but there are some flaws and ambiguities. You can see my comments as follows:

·        I suggest that the title of the article be more detailed. For example, it is possible to refer to the TVDI index and the study area in it.

·        Research gap should be mentioned in the Abstract. What was the challenge in previous studies that made you conduct this research and use new methods?

·        One of my general questions is whether the FY-4A Satellite Images data is available for other researchers to use and compare with your work.

·        Page 2. In the last paragraph of the introduction section, you should not focus on the results and instead focus on the objectives, contribution, and structure of the presentation.

·        Page 5. It seems that you missed the explanation of how to calculate parameters a, b, c, and d in equations 2 and 3 in the result.

·        Page 5. Since the values of TVDI compared to SRHI and MCI are somewhat opposite (for example, more TVDI is equivalent to more drought, while more SRHI indicates less drought), so the greater the negative correlation between them, the better the results. In this case, how do you justify the not-so-high values of 13.4%, 4.1%, and 50.6%?

·        Page 6. How did you come to the conclusion that overall TVDI and SHRI trends are consistent? You need to provide more concrete facts.

·        Page 9. Explain the way that you classified the drought maps. I mean based on equal intervals, Natural breaks, etc. Because the chosen method is very effective in the results.

 

·        Page 10. Drought is a phenomenon that occurs gradually over time, but meteorological satellites frequently receive information from the surface of the earth. Is it necessary to go to geostationary meteorological satellites to study drought? I think you should discuss how much the computational cost increases as well.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear Editor

All the comments have been answered well and the problems have been fixed. Also, to improve the innovation of the study, the comparison among MODIS, Landsat satellite and FY-4 results has been added. Furthermore, adding trend analysis has made the study more interesting.

This article qualifies for acceptance.

 

 

Reviewer 3 Report

I think the article is acceptable in its current form.