Dear authors; thank you very much for considering the reviewers' comments. At those points very you disagree to the opinion of the reviewer, I can follow your arguments. For all other points it looks as if you already have ideas how to improve the paper. So I am sure that you will be able to provide a revised version with a moderate effort. As both reviewers suggested a major revision, I would like them to take a look at the revised version, but I am positive that the revised version can be published within a reasonable time frame. All the best, Stefan

Dear authors; sorry for the delay in the second round of review! One of the reviewers was obviously satisfied with your revisions, while I was not able to get a response from the other reviewer. I therefore checked your manuscript with regard to this review finding it appropriate. So I think the paper can be accepted without waiting longer for the review. However, I still found many little technical mistakes, in particular in the format of the references in the text, but also in the reference list (e.g., Zehe et al. 2013) and in the format of physical units (e.g., stars between units). I would therefore ask you to check your manuscript once more thoroughly before uploading the production files. All the best, Stefan