An Approach to the Temporal and Spatial Characteristics of Vegetation in the Growing Season in Western China

Round 1

Reviewer 1 Report

The manuscript „An Approach to the Temporal and Spatial Characteristics of Vegetation in the Growing Season in Western China“ is an interesting and relevant contribution to the field of remote sensing science.

In my opinion, this paper suits well into the scope of the Journal. Moreover, It is methodologically sound (with strongly developed statistical analysis) and well-written.

My comments mostly refer to form, presentation and discussion, and I hope the consideration of them will make the manuscript better readable and more explicit regarding the merits it already has. However, I have some suggestions that may improve the article.

SPECIFIC COMMENTS:

Abstract:

1) L11-32: The abstract doesn’t contain any information about innovation. The abstract must state the innovation in the conducted research in two or three sentences.

Keywords:

2) L33-34: Please find such words which are not in the title, this way search engines of the web will find your manuscript with higher probability.

Introduction:

3) L37: abbreviations must be explained

4) L71: Are all those references relevant? If so I would suggest that you group them according to categories or applications rather than just placing them together. In this form, there is little evidence that they have been read and there is no indication of their respective importance to the subject.

5) L37-87: Reference overkill, i.e. using more than 3 references per sentence, should be avoided. In this form, the key idea of each single reference should be mentioned.

Data and Methods:

6) L95-96: add missing source/reference(s)

7) L104: Figure 1: poor quality.

8) L134-147: add references when MK test was used. About MK test see also research: https://doi.org/10.1080/10807039.2018.1506254 when this test was used. In this case see also information about Monte Carlo simulation

Results and Discussion:

9) L199: Figure 2: Blue indicates year, but the description of the horizontal axis is 1, 2, .., 5. It is incorrect.

10) L213: where is fig. 4?

11) L233: Figure 3 and Fig. 5: Please increase the quality of the figure

12) Table 2 is missing.

13) This section is mostly correct. However, in my opinion, the authors quote too few references in it. If this is a discussion section, more literature should be cited.

14) In Discussion section, the authors should discuss the results of the research and compare them with other recent studies.

Conclusions:

15) What are the weaknesses and limitation of the research carried out?

References:

16) Follow the guidelines for authors.

Language:

17) The text needs some language editing, including punctuation.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

Some reviews:

1) Figure 4 must be improved. Low resolution and not recommended to publish. 

2) The analysis should have some examples of vegetation (pictures). This could improve the paper and give some ideas about the region and vegetation regeneration and/or degradation. I don´t know if some fieldwork was possible, but some photos with the type of vegetation could be shown

3) Some words are not common: "luxuriant" or "reclamation vegetation". I recommend changing. 

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

 

The authors develop a spatio-temporal analysis of the variation of the vegetation characteristics in the western part of China using robust techniques of mathematical statistics that show a more comprehensive dynamic to facilitate subsequent analysis of degrading factors and that will serve as a basis for management of restoration and environmental protection in that area.

 

The mathematical statistical methods are sufficiently well explained given the originality and robustness of their use in this study

 

The results are thoroughly interpreted and in a quantitative way in terms of internal variation of the vegetation in each zone and its evolution along the years analysed. It is good that they also provide an explanation of the meaning and significance of the statistical parameters

 

Below are some specific criticisms that can clarify and improve the presentation and understanding of the work

 

• The authors may know that MODIS greatly improves scientists’ ability to measure plant growth on a global scale so that the MODIS Science Team introduced the Enhanced Vegetation Index (EVI) that clearly improves upon the quality of the NDVI product <https://earthobservatory.nasa.gov/features/MeasuringVegetation/measuring_vegetation_4.php>. NDVI is still used to maintain the consistency of the series originally developed with NOAA AVHRR data. Thus, Section 2 on data sources and processing should give an explanation on why using NDVI instead of EVI in this work

 

• Reorder adequately the numbers of the figures. Figure 4 seems to be missing

 

• Figures in Table 3 should be revised with respect to the given significant figures. For example, “Moran’s I” is given with a significance of 1 unit in about 50000 (0,002%), “mean FVC” in 1 unit in about 40000 (0,003%) and “variation coefficients” in 1 unit in about 2600 (0,04%). It is not credible, for example that the coefficient of variation of a “mean FVC value” can be determined to an accuracy of 0,04% using remote sensing data every year in the whole of Western China. Uncertainty of the results should be assessed as a function of the accuracy of the data and algorithm propagation errors.

 

• Similar comments are given with respect to Table 4. The parameters “Direction Angle”, “X-axis length（km)", “y-axis length（km)”, and “The shape of Index” are given with too many significant figures. Just consider that the table provides “standard deviation” which is an “uncertainty parameter” with a significance of 1 unit in about 10000 to 17000 (0,01% to 0,006%). Angles are also given with about 0,001% significance. Please write the abbreviation of "kilometers" as "km" and not "KM"

 

• Please explain the meaning of the “Lisa value” (Line 164), “local Lisa index” (Line 172), “Lisa aggregation evolution chart” (Line 283), “Lisa cluster diagram” (Line 288), and “Spatial local Lisa map” (Line 344)

 

• Section 3.3: Please explain the meaning of “L-L aggregation” and “H-H aggregation”

 

• Section 3.4: Similarly to what was previously done with the less commonly used statistical parameters, please give an explanation of the meaning of the different “standard deviation ellipse (SDE)” parameters and the significance of the variation of the ellipse in the results

 

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The article after improvement has gained on quality. The manuscript has gone through a significant revision as compared to the earlier version.
Currently, I recommend accept this manuscript for publication.