Integrated Analysis of Water Ice Detection in Erlanger Crater, Lunar North Pole: Insights from Chandrayaan-1 Mini-SAR and Chandrayaan-2 DFSAR Data

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. The "Study Area" section contains too little useful information. It is recommended to add a detailed information of the region.

2. It is recommended that a more detailed explanation be provided on how to derive the Stokes vector S from the raw data to better assist readers in understanding the process.Standardize the format of equation expressions, for example, equation (16) can easily confuse the definition of CPR.

3. Could a theoretical framework be added to link the observed polarization characteristics with the specific physical properties of water ice?

4. The study lacks an effective validation for the detection results of water ice. Although CPR values are used as indicators, there is no independent validation through other datasets or methods.

5. The article claims a correlation between the hybrid polarimetric model and fully polarimetric parameters, but lacks rigorous theoretical derivation or statistical analysis. Therefore, the current presentation is mainly qualitative, and it is suggested to add quantitative indicators to support the correlation.

6. It is recommended to include specific suggestions for future research directions in the conclusion.

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This paper utilizes various decomposition models to process the Chandrayaan-1 Mini SAR data and Chandrayaan-2 DFSAR data. The main research subject is the Erlanger crater in the permanently shadowed region. The results show different distributions of volume scattering, surface scattering, and double-bounce scattering at the location of the crater under study. Additionally, the paper concludes the presence of ice within and around the impact crater based on high CPR. The main issues are as follows:

1.    Mathematical Formulations: The paper contains several mathematical formulations that require revision. Please ensure the correctness of the derived results and to include relevant references.

o    Formula 1 has incorrect expressions for S3 and S4, and the overall formula needs to include <> to represent the average effect.

o    Formula 4 appears to be missing a negative sign [Reference: The m-chi decomposition of hybrid dual-polarimetric radar data with application to lunar craters].

o    Formula 5 lacks squares for S2 and S3.

o    The description of m=0 as an "unpolarized wave" is inappropriate.

o    Formula 7 should be placed on the same line.

o    Formulas 13 and 14 seem to be out of order [Reference: DECOMPOSITION METHODS FOR DETECTION OF OIL SPILLS BASED ON RISAT-1 SAR IMAGES].

o    Formula 16 should be formatted according to standard conventions.

2.    Volume Scattering and Roughness: The paper did not address the relationship between volume scattering and surface roughness. There is a need for an analysis of the bottom and edge roughness of the crater and a discussion on the possibility of ice presence. Additional literature should be cited to support these claims.

3.    Scattering Type and Incidence Angle: The paper does not discuss the relationship between scattering type, CPR, and the incidence angle, particularly with respect to the crater walls and bottom.

4.    Introduction Section: The terms "lunar atmosphere" and "surface" in the introduction are inconsistent. It is recommended to use "lunar surface environment" consistently throughout the paper. The introduction should also be updated with the latest relevant references.

5.    Study Area Description: The description of the study area is too simplistic. It is advisable to provide a more detailed description of the study area, incorporating Figure 1 for clarity.

6.    The abbreviation DFSAR is mentioned on line 22 but should have been introduced on line 19 for consistency.

7.    Figures:

 The color bars in Figures 4-8 have two R's, which is confusing. Figure 9b lacks a caption, and add marks in Figure 11a to point to the location of Figure 11b.

Figure 12 shows a red linear feature that may be noise rather than an ice signal.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

After carefully reviewing the content and quality of this study presented, I am pleased to recommend this manuscript for acceptance in RS.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have made modifications to the paper, but there are still some issues remaining.

1. The revised manuscript has corrected the overall formulas, but the obtained results have not been updated.
2. The definitions of surface scattering, double scattering, and volume scattering in the revised manuscript differ from those in the existing literature. Please carefully check and include relevant references.
3. Ref: Kumar, L. J. V., Kishore, J. K., & Rao, P. K. (2014). Decomposition methods for detection of oil spills based on RISAT-1 SAR images. Int. J. Remote Sens. Geosci, 3(4), 1-10. The cited literature does not lead to formula 12. Please review.
4. Please add some discussions on the incidence angle. The related reference is Thompson, T. W., Ustinov, E. A., & Heggy, E. (2011). Modeling radar scattering from icy lunar regoliths at 13 cm and 4 cm wavelengths. Journal of Geophysical Research: Planets, 116(E1).

Author Response

Please see the attachment.

Author Response File: Author Response.pdf