Dear Authors,

We have received two sets of reviewer’s comments that vary in their level of criticism. I carefully looked at the paper and at the reviewer’s comments and I believe that both reviews provide very valuable comments that will help improve the revised manuscript and enhance its scientific contribution. I agree with reviewer #2 in that the manuscript presents novel material but that it needs major revisions to be considered for publication.

I appreciate that the authors have provided extremely detailed responses that make the discussion rich and useful for the scientific community. I hope that all key elements of this discussion will be included into the revised paper. In summary:

Reviewer #1 has expressed serious concerns about the validity of the approach. I appreciate the detailed responses of the authors. I believe that including these clarifying statements and information will substantially improve the revised manuscript.

Reviewer #2 has clearly stated a number of questions about the methodological approach. The authors have provided answers in the response letter. Please note that these details need to be incorporated in the paper. To avoid generating an unnecessarily long paper, the authors should perhaps consider including the basic description in the paper and the rest of the methodology as supplementary material.

Sincerely,
Patricia Saco

Dear Authors,

We have now received two referee reports. After my own assessment of the revised manuscript, I agree with the reviewers that the manuscript has been substantially improved through the incorporation of the reviewer's suggestions and by including a better description of the methodology.
I believe that the manuscript is almost ready for publication, but first please carefully consider the minor comments and suggestions of reviewer #2.