Radiometric Re-Compensation of Sentinel-1 SAR Data Products for Artificial Biases due to Antenna Pattern Changes
, Marco Schwerdt 1, Guillaume Hajduch 2, Pauline Vincent 2, Andrea Recchia 3 and Muriel Pinheiro 4Round 1
Reviewer 1 Report
This paper introduces a method for correcting artificial radiometric biases within Sentinel-1 SAR data products due to the change of antenna elevation patterns and processing gains. The proposed solution can be done without full reprocessing of SAR data products. The proposed method is technically feasible and has achieved very good experimental results.
The paper may be further elaborated in the following aspects.
1. Quantitative evaluation of the improvement of radiometric accuracy. In this paper, only the evaluation results of individual SAR data were given. However, for Sentinel-1 SAR satellite, there are many wave positions or beam directions. Can authors give the statistical improvement of the radiometric accuracy of different positions?
2. From the given experimental results, the proposed method did effectively improve the radiometric accuracy. However, the value of the improvement is small. From the perspective of SAR applications, which applications may have positive or obvious effects from this improvement?
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper addresses a specific topic of introducing corrections into already acquired Sentinel SAR data. The observations presented by the authors are important for people dealing with the classification of such data and some measurements carried out SAR images. The paper is written well but I feel some disbalance (the historical part of the Introduction is too long). There areal the following recommendations how to improve the paper or its significance:
1) page 4: correct for re-compensate to for re-compensating
2) Please explain outliers in the lower scatterplot in Fig. 4
3) Are the radiometric errors only due to changing antenna pattern? Are there other factors?
4) Please think about how to inform potential users of Sentinel SAR data about dates of corrections. Not everybody will read this paper in the journal. Maybe, it has to appear at Sentinel data site (if accepted).
5) Are there some trends in changing radiometric coefficients?
5)
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
