Dear Authors, unfortunately you have not exploited the advantage and opportunity in the hess-d phase of possibly interacting with the referees by sending your responses and comments before the closure of the open discussion. I believe that some referees' comments require some careful, additional evaluations.

Dear Authors,
While you have well addressed most of the previous referees’s comments, as also acknowledged by one referees, there are still some parts of the manuscript deserving attention prior a final acceptance is made. For example, some of your replies should be inserted into the new version, as it is the case of the three bullet points about the novelty of the work on the first paragraph of your “Joint Response to Anonymous Referees 1-3”.
Overall, and more importantly in order to strengthen your work, I share one big concern of one of the additional referee about the fact that the validation issue of your proposed method is definitely not addressed properly. In your responses, you have just replied that in your study validation is a difficult process and that the necessary resources to carry out that task are unavailable at present. However, some sort of validation of your results is practicable, I guess, and required in order that confirm that any changes detected using these methods correspond to changes in the natural system and not because of external influences on the images such as soil reflectivity or the quality of the ambient light.
I release the manuscript for your consideration of the important points raised by Anonymous Referee #4. Please, provide a point-to-point response. Should you disagree with some comments, please clearly explain why.
I look forward to receiving the revised version.

Dear Authors,
I appreciate your thoughtful responses. The revised manuscript can be accepted as it is. Congratulations!
NR