Dear Patrick, dear co-authors

Many thanks for submitting a revised version of your paper about the fascinating L-WAIVE experiment. As you can see, the reviewer who asked for major revisions in the first round, mentions that the manuscript has improved, but fails in providing a consolidating vision, which is one of your main objectives. I also read your revised version and I agree with the reviewer that a further focusing and consolidation would greatly increase the value of this paper. My overall impression is that the paper tries to cover too many things and that leaving away certain aspects - those that are not essential for the water vapor isotope profiles - and discussing a bit more the key results could help a lot. Here a few more specific impressions I had when reading the paper:

1) Since I saw the paper for the first time, I found the title a bit cumbersome: to me, a simpler title like "A field experiment to investigate the vertical water vapor isotope profile above an Alpine lake" would be more appealing and informative.

2) I think your abstract has a rather weak ending. Lines 25-30, where you describe the first results from L-WAIVE contain very vague statements. In essence you write that there is a lot of variability depending on the synoptic circulation. To play the devil's advocate, you don't need to do a field experiment to come to this conclusion (this is obvious) ... your measurements and results contain much more precise and interesting information, and I would like to invite you to document some of them also in the abstract.

3) I agree with the reviewer that the paper has a strange starting point (ice melt, biodiversity). These phenomena and concepts never appear again in the paper; I think you can directly start with humidity profiles etc.

4) The title of the paper and the main objectives clearly focus on water vapor profiles and the stable isotope signals (which I think is perfectly fine!). However, the paper then also presents results about lake temperature profiles and aerosols, but I couldn't find out how these results influence your analysis of the vapor/isotope profiles. I rather felt distracted by the lake temperatures and aerosol results and had the impression that I was loosing track of the storyline. My suggestion is that you consider omitting these aspects of the paper and really focus on the instruments and data you need for the vapor profile analysis. This would also shorten the instrument description part.

5) On a more detailed level, I think the paper could be shortened in several places. It sometimes reads a bit too much like a campaign report. For instance, in line 157 you mention "golden days", but then I could not find further analysis of these golden days. So why should the reader know about golden vs. silver days?

6) I also suggest to show less synoptic charts. They fill 3 pages but are not really discussed in great detail. Also, the link between a few selected charts and the analysis of the profiles could be strengthened.

7) I am not fully sure what I should think of the artwork in Fig. 16. On the one hand, I like schematics, but here too many things are unclear to me. For instance, what is the 0.46 km label refer to (altitude of the lake?). Is the lake boundary layer then extending to 1 km above the lake? The abstract emphasises an altitude of 1.5 km above ground level, is this 0.46+1 km? I am confused. And maybe more importantly, how can you show a typical profile of RH if conditions were so variable? And why is the cloud located where your RH profile has a minimum? I tend to suggest that you better omit this schematic or establish a (much) stronger link to the actual measurements.

Despite my critical remarks, let me conclude by emphasising that I congratulate the team for collecting an impressive and highly valuable data set (with a very interesting measurement strategy), and that I hope that the comments from the reviewer and myself help you to further improve the manuscript.

With best regards,
Heini

Dear Patrick

Many thanks for the revisions of your paper. I agree with the reviewer that the paper is now much better streamlined and more attractive to read. I am happy to accept your paper for publication in ACP subject to very few corrections (see the suggestions by the reviewer). In addition please correct the following minor things:
- line 561: retrieved --> retrieve
- line 576: "in isotopes abundance" --> "in the abundance of isotopes"
. line 614: reference seems to be incomplete

Congratulations to this innovative field experiment and nice paper!
Best regards,
Heini