Spatiotemporal Dynamics of Aboveground Biomass and Its Influencing Factors in Xinjiang’s Desert Grasslands
Round 1
Reviewer 1 Report
Title: Spatiotemporal dynamics of aboveground biomass and its climatic factors in Xinjiang's desert grasslands
Overall, this paper is novel and the analysis of this paper is robust. This paper can generate implications on the carbon sequestration via biomass. However, authors have to make the following revisions.
Q1 Abstract: authors should add 1-2 sentences to indicate the research gap of existing studies.
Q2 Line 43, please remove Xinjiang. Such an explanation is suitable for all scenarios all over the world.
Q3 The description from the research gap to the research aim is not logic in line 69-75. Please revise.
Q4 Before line 104, authors should add a section on the inversion method. Why is this method good for understanding/ analysing? Please refer:
Mapping cation exchange capacity using a quasi-3d joint inversion of EM38 and EM31 data." Soil and Tillage Research 200 (2020): 104618.
3D characterization of crop water use and the rooting system in field agronomic research." Computers and Electronics in Agriculture 202 (2022): 107409.
Clay content mapping and uncertainty estimation using weighted model averaging." Catena 209 (2022): 105791.
Q5 Table 2, authors must add some references or some explanations.
Q6 In method section, authors have to add a section on the climatic factors you will consider.
Q7 RMSE, Accuracy, MRE and NSE are quite general for consideration. Please also use other indicators which are included in the recommended references.
Q8 Figure 3, please indicate the uncertainty.
Q9 Fig.10 any statistical analysis?
Q10 Fig.11, average data? Could you also indicate the temperature and precipitation variation from 2000 to 2019?
Q11. If authors have only considered the temperature and precipitation, it will be not proper to use climatic factors in the title of this paper.
Q12. Please make the analysis consistent with your description of the ecosystem in line 71.
Author Response
Response to Reviewer 1 Comments
Comment: Title: Spatiotemporal dynamics of aboveground biomass and its climatic factors in Xinjiang's desert grasslands. Overall, this paper is novel and the analysis of this paper is robust. This paper can generate implications on the carbon sequestration via biomass. However, authors have to make the following revisions.
Response to comment: Thank you very much for your time and effort in reviewing our manuscript and providing valuable comments and suggestions. We have carefully read the specific comments and tried best to revise this manuscript according to your suggestions and comments.
Major issues:
Comment 1: Abstract: authors should add 1-2 sentences to indicate the research gap of existing studies.
Response to comment 1: Thank you for your guidance. According to your suggestion, we have added related information to the abstract of the revised manuscript. ( line 14-15).
Comment 2: Line 43, please remove Xinjiang. Such an explanation is suitable for all scenarios all over the world.
Response to comment 2: Thank you for your guidance. We have modified this problem. ( line 45)
Comment 3: The description from the research gap to the research aim is not logic in line 69-75. Please revise.
Response to comment 3: Thank you for your guidance. According to your suggestion, we have modified this problem to the introduction of the revised manuscript. ( line 83-93).
Comment 4: Before line 104, authors should add a section on the inversion method. Why is this method good for understanding/ analysing? Please refer:
Response to comment 4: Thank you for your guidance. According to your suggestion, we have added about inversion methods. ( line 188-212). We have cited two of these references.
Comment 5: Table 2, authors must add some references or some explanations.
Response to comment 5: Thank you for your guidance. According to your suggestion, we have added some references and some explanations. ( line 397-404)
Comment 6: In method section, authors have to add a section on the climatic factors you will consider.
Response to comment 6: Thank you for your guidance. We have added a section on the climatic factors. ( line 348-356)
Comment 7: RMSE, Accuracy, MRE and NSE are quite general for consideration. Please also use other indicators which are included in the recommended references.
Response to comment 7: Thank you for your guidance. According to your suggestion, we have used some indicators in the recommended references. ( line 303-313)
Comment 8: Figure 3, please indicate the uncertainty.
Response to comment 8: Thank you for your guidance. We have indicated the uncertainty.in Figure 3. ( line 416-418)
Comment 9: Fig.10 any statistical analysis?
Response to comment 9: Thank you for your guidance. According to your suggestion, we have added s statistical analysis. ( line 515-522)
Comment 10: Fig.11, average data? Could you also indicate the temperature and precipitation variation from 2000 to 2019?
Response to comment 10: Thank you for your guidance. According to your suggestion, we have added trend charts depicting changes in temperature and precipitation. ( line 530-536, Fig.12)
Comment 11: If authors have only considered the temperature and precipitation, it will be not proper to use climatic factors in the title of this paper.
Response to comment 11: Thank you for your guidance. According to your suggestion, we have revised the title of the article. ( line 1-3)
Comment 12: Please make the analysis consistent with your description of the ecosystem in line 71.
Response to comment 12: Thank you for your guidance. According to your suggestion, we have revised the problem. ( line 83-88)
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear Authors
Your manuscript: “Spatiotemporal dynamics of aboveground biomass and its climatic factors in Xinjiang's desert grasslands” presents an interesting theme but whose Remote Sensing techniques are already well explored. It may be interesting to reinforce this issue and the difference presented in your study, which encompasses a larger temporal analysis. Another issue not addressed in the article and which deserves to be explored concerns the saturation of the NDVI index, especially in places with higher AGB values.
I have presented ten less impactful reviews presented in the digital text and would like your attention to the following aspects:
1) In the introduction, reinforce the importance of studying grassland in desert places. Introduce some more quotes.
2) Figure 1: improve the title and use letters to explain the two parts of the Figure. Use the same format for the other figures.
3) Please quote the total area of ​​Xinjiang.
4) Figure 2: would it be possible to add a land cover map showing the different types of grassland?
5) Table 1: please check the links to the data sources. They are not working properly.
6) On the spatial data, comment on the respective atmospheric calibration implemented in each model to correct the temporal variation of the data.
7) The analysis of table 2 allows us to assess that the AGB correction with spectral index did not present a good fit. In addition, this table would be a result and should be presented in chapter 3.
8) Line 173: “The Mann-Kendall test is a non-parametric statistical test”. In this case, was the normality of the data verified and therefore the option for this test?
9) From Figure 6 b, it is possible to present the areas for each thematic class and enrich the discussion.
10) Line 286: “However, the average annual temperature and precipitation may not accurately reflect the conditions in the study area”. Please explain this condition better.
11) Figure 11: explain the interpolation method used to obtain the maps in this figure.
12) Please introduce the problem related to the saturation of the NDVI index in the discussions. It is important to introduce this constraint.
13) Lines 319 to 321: “However, an uncertainty in the estimated grassland biomass is possible because of factors such as differences in study areas, seasons, and sampling methods”. Please delve deeper into this discussion as it has a significant impact on your study.
14) Please improve the conclusions and verify that all the proposed objectives were duly answered. You can see that there is still some discussion here
I conclude my review by congratulating them for their work and the presented version of the article.
Respectfully,
Comments for author File: 
Comments.pdf
Author Response
Response to Reviewer 2 Comments
Comment: Your manuscript: “Spatiotemporal dynamics of aboveground biomass and its climatic factors in Xinjiang's desert grasslands” presents an interesting theme but whose Remote Sensing techniques are already well explored. It may be interesting to reinforce this issue and the difference presented in your study, which encompasses a larger temporal analysis. Another issue not addressed in the article and which deserves to be explored concerns the saturation of the NDVI index, especially in places with higher AGB values.
Response to comment: Sincerely thank you for your comments. We are glad that our work has been recognized and acknowledged by you. Your comments will be of great benefit to us in our future scientific research and thesis writing. In the newly submitted manuscript, we have reorganized the structure of the paper, which is more standardized, and we have added to the saturation involving the NDVI index, especially where the AGB values are high.
Major issues:
Comment 1: In the introduction, reinforce the importance of studying grassland in desert places. Introduce some more quotes.
Response to comment 1: Thank you for your guidance. According to your suggestion, we added a problem statement to the introduction of the revised manuscript. ( line 45-63).
Comment 2: Figure 1: improve the title and use letters to explain the two parts of the Figure. Use the same format for the other figures.
Response to comment 2: Thank you for your guidance. According to your suggestion, we added a section that requires a letter explanation. ( line 170-172)
Figure 1. Geographical location of Xinjiang. (a) Administrative regionalization of China; (b) Topographical map of Xinjiang.
Comment 3: Please quote the total area of Xinjiang.
Response to comment 3: Thank you for your guidance. We supplement the total area of Xinjiang. ( line 97)
Comment 4: Figure 2: would it be possible to add a land cover map showing the different types of grassland?
Response to comment 4: Thank you for your guidance. We added a land cover map. ( line 184-186)
Comment 5: Table 1: please check the links to the data sources. They are not working properly.
Response to comment 5: Thank you for your guidance. We have corrected the links to the data sources. ( line 259)
Comment 6: On the spatial data, comment on the respective atmospheric calibration implemented in each model to correct the temporal variation of the data.
Response to comment 6: Thank you for your guidance. We have added a comment about atmospheric calibration. However, the SPOT-NDVI and NOAA CDR NDVI data we downloaded are already processed and do not require atmospheric correction. ( line 223-252)
Comment 7: The analysis of table 2 allows us to assess that the AGB correction with spectral index did not present a good fit. In addition, we have put Table 2 in Chapter 3.
Response to comment 7: Thank you for your guidance. Many factors that affect AGB. We are subject to errors in sampling and weighing. However, the exponential function fitted the best, with an R2 of 0.68. In addition, the table 2 would be a result and should be presented in chapter 3. ( line 396-404)
Comment 8: Line 173: “The Mann-Kendall test is a non-parametric statistical test”. In this case, was the normality of the data verified and therefore the option for this test?
Response to comment 8: Thank you for your guidance. The NDVI data showed a significant increasing trend ( p < 0.001 ) from 2000 to 2019, which did not conform to the normal distribution of the data. The MK test does not require the data to be normally distributed or the trend to be linear, which is suitable for non-normal distribution data
for long time series such as hydrology and meteorology. Therefore, we use the MK test to analyze trends in NDVI data.
Comment 9: From Figure 6 b, it is possible to present the areas for each thematic class and enrich the discussion.
Response to comment 9: Thank you for your guidance. We have present the areas for each thematic class and enrich the discussion. ( line 445-456)
Comment 10: Line 286: “However, the average annual temperature and precipitation may not accurately reflect the conditions in the study area”. Please explain this condition better.
Response to comment 10: Thank you for your guidance. According to your suggestion, we have better explained this condition. This part has been added to the article. ( line 530-536).
Comment 11: Figure 11: explain the interpolation method used to obtain the maps in this figure.
Response to comment 11: Thank you for your guidance. We use a spline function interpolation function to interpolate the temperature and precipitation data. This part has been added to the article. ( line 512-513).
Comment 12: Please introduce the problem related to the saturation of the NDVI index in the discussions. It is important to introduce this constraint.
Response to comment 12: Thank you for your guidance. According to your suggestion, we added information about the saturation of the NDVI in the discussion (line 665-678).
Comment 13: Lines 319 to 321: “However, an uncertainty in the estimated grassland biomass is possible because of factors such as differences in study areas, seasons, and sampling methods”. Please delve deeper into this discussion as it has a significant impact on your study.
Response to comment 13: Thank you for your guidance. According to your suggestion, we added information in the discussion (line 597-603).
Comment 14: Please improve the conclusions and verify that all the proposed objectives were duly answered. You can see that there is still some discussion here
Response to comment 14: Thank you for your guidance. According to your suggestion, we added information in the discussion (line 704-706).
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Authors have well addressed all my comments.
Reviewer 2 Report
Dear Authors
The second version of your manuscript: "Spatiotemporal dynamics of aboveground biomass and its influencing factors in Xinjiang's desert grasslands" presents important changes that make the reading fluid and understandable.
Regarding the Mann-Kendall test, please add to chapter 2.4.4: "The NDVI data showed a significant increasing trend ( p < 0.001 ) from 2000 to 2019, which did not conform to the normal distribution of the data. The MK test does not require the data to be normally distributed or the trend to be linear, which is suitable for non-normal distribution data for long time series such as hydrology and meteorology." This format helps the reader to fully understand the choice for that test and the non-normality of the data.
Thank you for sending the cover letter facilitating my work in this second round of review.
Respectfully,
