Multi-Temporal and Time-Lag Responses of Terrestrial Net Ecosystem Productivity to Extreme Climate from 1981 to 2019 in China

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 

The manuscript addresses the NEP time-lag responses to extreme climate in multi-temporal. The manuscript uses a number of indicators of extreme climate; however, it lacks an in-depth exploration of the selection process for extreme climate indicators and the analysis of lag response causes. Consequently, the confusion over the chosen climate indicators, the interpretation of the results or the mechanism, is not perfect for me, and I suggest that this manuscript needs major revision.

 

Specific comments:

 

In the spatio-temporal dynamic analysis of NEP, the average NEP ranges from -123 to 201 (fig.3a), while the probability distribution spans from -20 to 90 (fig.3d). What are the reasons for these differences, the removal of certain pixels? Fig. 3.b and Fig. 3e also have inconsistent ranges. Furthermore, the trend of NEP in Southwest China from 1981 to 2019 is approximately 100, whereas the average over the past four decades is around 200, which raises concerns regarding potential calculation errors or units. I would suggest that the authors double-check the data analysis.

 

The authors give the reasons for choosing these meteorological indicators that are simple to understand and have wide applicability, as they have been used in previous studies. However, readers would be inclined towards comprehending the underlying reasons and mechanisms through which these indicators impact NEP, rather than solely focusing on their widespread usage. This aspect should also be further explored in Chapters 4.2 and 4.3, instead of relying on generic citations as the current version.

 

The method of lag month is defined according to the author, lag month with the highest R2 value determines the optimal lag time for NEP response to the extreme climate factor. The current description of the results is seriously inconsistent with fig.7 For example, forests seem to respond to temperature with a lag of 2 months, not 4 months as the authors mentioned. It is strongly recommended to reorganize the description text and figures to ensure that the text is consistent with the results in the revised figures. The results of the current version are confusing and hardly enlightening to the reader.  The author should further analyze the intriguing phenomenon of phase transformation in the response relationship (from positive to negative or from negative to positive) for different lag months, as it presents an interesting result worthy of investigation.

 The manuscript language organization and graphic expression should be strengthened. The declarative result is too tedious and lacks conciseness.

 

Comments for author File: Comments.pdf

Comments on the Quality of English Language

The manuscript needs extensive revision for language.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Though the work is largely well-written, the article still needs significant improvement in the introduction, methodology, and conclusion sections. Considering my observations as follows, I suggest that the paper undergo major revision before considering it for publication.

 

·       The abstract is not clear to me. Please provide more concise and clear information   regarding methodology and results of the study in the abstract.

·       I suggest reformulating the research gap in a manner consistent with the novelty presented in this study

·       Is it possible to update some references in introduction?

·       A methodological flow chart is very important for clear understanding of the methodology of the study.

·       A table of the data, including the types of data, the sources, and how it was used in the study, is necessary.

·       The authors used the “Boreal Ecosystem Productivity Simulator (BEPS)” model to generate the carbon flux of terrestrial ecosystems. I need more detailed explanations of this model. How is the model built? I mean the input parameters of the model, the calibration, accuracy and validation of the model, etc.

·       Although the language of the manuscript is good, I suggest using the Grammarly tool, for example, to correct some simple linguistic errors.

·       Is it possible to update some references in discussion?

·       I suggest adding a paragraph that specifies future applications and benefits from the results of this study.

Comments on the Quality of English Language

Moderate editing of English language required.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Sirs,

I found your paper interesting and deeply developed as regards methodology and analysis of results. I appreciated your constant referring to the significance of results, an aspect not always clear in other works.

Some minor criticisms are reported in the attached revised text. I recommend pubblication after a minor revision,

best regards

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The author addresses most of my concerns.  There is only one issue that needs further clarification.

 

Line 205, Although the author adds a definition of the length of the lag time, it is still confusing. What does that mean? “The latest time for R2 to manifest as significant was defined as the longest response time.” Grammatical errors.

 

It is necessary to check the grammar of the full text carefully. 

 

Line 75-79, Please cite relevant and correct references.

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf