Evaluation of Future Trends Based on the Characteristics of Net Primary Production (NPP) Changes over 21 Years in the Yangtze River Basin in China
Round 1
Reviewer 1 Report
Manuscript ' Characteristics of NPP changes in the Yangtze River Basin and its future trends over the past 21 years'. This paper illustrates well the spatial variation characteristics and future trends of the NPP in the Yangtze River Basin by using coefficient of variation (CV), trend analysis (β) and Hurst index (H) methods. The subject area is very relevant and topical, which is useful for provide effective data support for regional differentiated policy formulation. What’s more, the paper provides a valuable foundation for the further research. However, there are some issues needed to be addressed before acceptable to the Journal.
The introduction section has a confused logic and needs further revision
The sentence structure in the article is too monotonous, and there are many sentences that are completely repeated. Such as L67 and L69.
English very difficult to understand. The English in the article requires professional polishing
Fig.1 There are errors with Guangdong and Henan.
L133-135 Considering the large area of the Yangtze River Basin, as well as its complex terrain and cloudy climate. How is data quality ensured?
The variables in the formulas in the MS should be formatted in italics
L240 Reference should be provided for the average temperature.
L241-L243 Fig 2? Shouldn't it be Fig. 3?
L252 Fig 3? Shouldn't it be Fig. 4?
The figures in the MS are not clear. It is recommended to increase the resolution and ensure that they are properly cited within the MS.
How to perform correlation analysis between NPP and temperature, precipitation, etc.
Fig. 11 is recommended to be further revised and beautified
Extensive editing of English language required
Author Response
Dear Reviewer：
Thank you for your suggestion. All modifications related to your suggestion are included in the report.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Since there were some critical problems and errors in this research article, This research article should have to revise before the publication of one of research articles for international journal, "Sustainability".
Please refer followings
[Major reversion]
1) Title
Please use more specific and simple title to understand more easily.
Ex.) Evaluation of futurte trends based on the characteristics of net primary productio(NPP) changes over 21 years in the Yangtze river basin in China
2) Keywords
Please use at least 5 important terms for "Keywords".
3) Objective(s), Line(L) 89-109
I think that these contents are too general and relatively long.
Please revise using more specific contents based on the viewpoint of globalization not only a specific reason or a nation.
4) Sub-title, L 494
4.1. The increase ~ for the
There was uncomplete sentence. What is this?
Do you think that is it a research article which was submitted to peer-review?
Editorial board need to reject or reconsider this research article.
5) Applicability in conclusions, L 587-621
Authors' need to consider why is thi researh important?
Where and how can we apply based on the results of this research article?
[Minor reversion]
6) Effective numbers, L 20, 28, 30.
Please use same effective numbers in a same contents, research article, Table etc. (in all contents)
EFNs 4: 1.024, 0.1126, 9.850
EFNss 3: 1.02, 0.113, 9.85
7) Figure 2.
Please add sub-title for each axis
8) Index in Figure 3.
Please use followings
NPP Sum. or NPP Summation
9) Y-axis's title in Figure 7
Please add Y-axis title
10) Contents' color in Figure 12.
Please change contents' color in order to understand more easily.
Minor editing of English language may be required
Author Response
Dear Reviewer：
Thank you for your suggestion. All modifications related to your suggestion are included in the report.
Author Response File: Author Response.pdf
Reviewer 3 Report
Dear authors,
Please find below comments on your article titled “Characteristics of NPP changes in the Yangtze River Basin and its future trends over the past 21 years”, where you investigate changes in Net Primary Productivity across the Yangtze River Basin through calculating the coefficient of variation, Theil-Sen trend estimator (and Mann-Kendall test), Hurst index and correlations with environmental variables.
The article seems to use appropriate methods to reach its conclusions, and the conclusions seem to be appropriate. The English is generally clear and understandable. However, there are many errors and omissions in the presentation of the work, and in places it seems almost unfinished. The background information and the interpretations of the results are useful in understanding the implications of the work in its geographical context.
On its own, the work appears to be useful for the readers of the journal. However, as the authors note, there are other recent articles that present results from similar studies (e.g., references 25 and 26). The authors do not state what the current work adds to the literature. Given the other similar works, I think that the authors need to explain what their work adds to the scientific knowledge around NPP in the Yangtze basin, as this is currently missing from the article.
While I note that this was an interesting article to read, I think that there are lots of changes required to bring it up to the standard required for the journal, before publication.
Please find below some more specific comments on the work, relating to changes that I think are required:
- Net primary productivity (NPP) is not defined in the article. A more complete statement of what this is and why it is important would be useful.
- Line 27: “and 22.10%” should not be here.
- Line 32: “-0.874 and 0.910”. Can you explain why there are multiple values here? It’s not clear from the rest of the abstract.
- Line 44 and elsewhere: “CO2” is normally written with a subscript “2”.
- Line 67 to 69. This is a duplicate of an earlier sentence.
- Line 95 to 96. This sentence does not make sense. Surely, the Hurst index is used to understand the trend, so that it needs to be introduced anyway?
- Line 116: The wording here is unclear. What exactly does the 1000km length refer to? It cannot be the width of the river.
- Line 128 and elsewhere: “||” should be “//”
- Line 130: what is MRT?
- Line 132: what is NPP_QC?
- Line 133: how are medium and high-grade quality defined?
- Line 139: How was the change in vegetation CO2 uptake assessed?
- Lines 143-153: This paragraph mostly duplicates the previous one.
- Line 153: what unit is 500?
- Line 154: What does “a three-step ladder” mean?
- Line 163: how was grading done?
- Line 167: what is LUCC?
- Line 180: I do not think that i is the variable – it is the index, so that this sentence is not correct.
- Line 181: I think “width” should be “length”
- Line 186: It is not correct that the Theil-Sen and Mann-Kendall methods require the data to obey a certain distribution.
- Line 187: rather than avoiding data errors existing, these methods are robust against outliers that might be introduced by data errors.
- Lines 200-202: The mathematics here is badly formatted and the letters don’t match with what you have used elsewhere. E.g., what is “ZC” and what is “a”? This looks like a copy-and-paste error. Please can you rewrite this sentence to make its meaning clearer? It is not alpha that passes the test. Alpha is the significance level.
- Line 206: what is tau?
- Line 208: I think “outlier” should be “deviation”
- Line 210: I think “polarity” should be “polar difference”
- Line 215: what is alpha?
- Line 216: how is the Hurst index calculated and how is it related to the equations given previously?
- Line 218: can you explain what you mean by “sustainability” here?
- Line 225: what are x and y? without knowing this, it is not clear what this figure shows.
- Line 234: duplication
- Line 240: what is “*”?
- Line 251: duplication of unit
- Line 251: maybe “referred” should be “relates”?
- Figure 4 and most other figures: legends are too small and blurry to read
- Figure 5: it is best not to use the same colours with reversed meaning on two neighbouring plots
- Line 326: I think this sentence needs to be rewritten. NPP and highest temperature are different variables, so testing for difference between them makes no sense. I assume that this is not what you have actually done.
- Figure 9: the right plot includes no additional information not already included in the left one.
- Figure 10: what is EVE?
- Line 391: please cite the relevant literature
- Figure 13: why are categories joined by lines? Surely, you should have a separate line for each category, with year along the x-axis? LULC is also not defined.
- Line 554: duplicate word
- References: the style is inconsistent, with some names reduced to initials and some journal names capitalised.
The English is generally clear and understandable, but there are some sentences that should be rewritten to make their meanings clear. I have noted these in my comments to the authors.
Author Response
Dear Reviewer：
Thank you for your suggestion. All modifications related to your suggestion are included in the report.
Author Response File: Author Response.pdf
Reviewer 4 Report
Very good, interesting and innovative paper dealing with the estimation of Primary Net Production (PNP) of ecosystems in large scale, using new technology tools taking into account relative secondary disadvantages of such important and difficult work.
Please improve (maximize) the colour explanations of all figures presenting maps.
Also explain what is NDVI in page 2, line 84.
Author Response
Thank you very much for your suggestions on my manuscript. Based on your advice, we have made the following modifications:
Point 1:Please improve (maximize) the colour explanations of all figures presenting maps.
Response 1 :We have made adjustments to the legend to make it easier to understand.
Point 2:Also explain what is NDVI in page 2, line 84
Response 2:We have included the definition of NDVI: Normalized Difference Vegetation Index.
Round 2
Reviewer 1 Report
The MS has been sufficiently improved to warrant publication in Sustainability.
Minor editing of English language required
Reviewer 2 Report
Since this article was well revised based on reviewer's commemts., this research article may suitable for the publication of one of research articles in international journal, "Sustainability".
I think that english was relatively good. But editing of eglish language may be more useful to all reders.
