Round 1

Reviewer 1 Report

1         General Comments

 

Low coherence is a crucial challenge to avoiding misinterpretation of results in satellite geodesy (https://doi.org/10.1109/TGRS.2006.870440, https://doi.org/10.1080/01431169608948741). This issue is still pending to evaluate in the present. This manuscript tries to establish a relationship between NDVI and coherence using regressions and first-order statistics. The manuscript is not suitable in its current form to be published or have a broader impact in an international journal.

My main concerns are

·         Despite the methodological contribution, the manuscript lacks science or research questions to be assessed.

·         The research needs a research question to be answered here. For example, http://dx.doi.org/10.1080/01431161.2017.1317944 show the feasibility of using L-band to carry out InSAR time series with good agreement in forest and dense vegetation cover (validated again with cross-validation in http://dx.doi.org/10.1016/j.jsames.2020.102587). I suggest that the authors delimitate the main question and how the methodological approach supports them.

·         The contribution is over-biased by the C-band use, and L-band showed better performance (see the previous point). I would recommend focusing the estimations on applicability, such as pre-estimation of coherence for band C in non-studied zones or multitemporal NDVI estimation using coherence values.

 

I believe that the contribution could benefit the scientific as a technical note despite a deeply worked article. The manuscript -polished and rewrited – could contribute to early-career scientists that need “hints” in the early SAR introduction. I encourage the authors to improve the document and submit a revised version. However, the current contribution is unsuitable and doesn’t show scientific novelty in its current form.

2         Specific Comments:

 

Lines 89: Please, detail the date of acquisition. Is unclear the dates and the representativity of the study (please, insert in the main text). I would propose including several dates along 2014-2022 considering removing dates with snow cover.

Line 97: Include dates acquisition for optical satellite data

Line 129: Please, delete extra space.

Lines 131-133: The authors should discuss and support small temporal and spatial baseline use. I would propose to include a sensitivity of coherence assessment for bperp.

Line 140: Please, change P by \rho

Line 178-180: Please, review the format.

Lines 186: Please, review the format and text

Lines 223: I would suggest standardizing the variables. Ndvi corresponds to NDVI.

Line 227: Value not shown in Figure 2A. Moreover, additional values are referenced to figures without clear identification in the respecting pictures. Please, clarify the relation between the text and figures in the manuscript.

Lines 257-260: “The fitting function γ 1 etermined in Section 2.3.2 and the NDVI images preprocessed in Section 2.1 are used to calculate the coherence coefficient. Comparing the calculated coherence coefficient with the real coherence coefficient, the error can be obtained to evaluate the precision of the fitting function. The error calculation equation is shown in (15)”. The sentence corresponds to the methodology, and please introduce sentences in the correct sections. Some figures of procedure seem as results instead of methodology also.

Lines 264-266: “For example, one of interferometric pairs is selected to verify the precision of the fitting function in ROI1. The reference imaging time is August 15, 2019 and the secondary imaging time is August 27, 2019. ”. The results seem only applicable to a reduced window, and the current form of the study is not suitable for extrapolation.

Lines 278-279: “It can be seen from Figure 5c that the color of the northern part of the study area is almost green or blue green, indicating small error values.”. I would suggest describing using values instead colours. Please, remember people with visual limitations could use this contribution.

 

Figure 6: Please, improve the figures. The current form is not suitable for publication, and the error cannot show counts. Please, use physical values in figure a and b introducing variable name in color bar.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Autors, please see the attached document.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Dear authors 

Thanks for answering my comments. I don't have additional concerns.

 

 

Author Response

Thank you for your careful review. We really appreciate your efforts in reviewing our manuscript during this unprecedented and challenging time. We wish good health to you, your family, and community. Your careful review has helped to make our study clearer and more comprehensive.