Assessing Stream Thermal Heterogeneity and Cold-Water Patches from UAV-Based Imagery: A Matter of Classification Methods and Metrics
Round 1
Reviewer 1 Report
Generally, I found this work being well documented and written, and in my opinion should be considered for publication. From the ecological perspective, this kind of data, if computed at large scale, might help in the run to increase the number of remotely computed water variables (see e.g., https://doi.org/10.1038/sdata.2015.73 or https://doi.org/10.1007/s00027-019-0624-5).
Some aspects caught my attention, and I would like to address to the authors:
- Validation is listed as one of the objectives in the Abstract, but don’t found it thoroughly addressed in the manuscript. As ecologist, I am expecting to see an in-situ validation by water temperature measurements and then compared with the remotely collected data.
- There are a series of variations that can be influential for water temperature and the authors did not discussed in the frame of their results: seasonal, altitude and latitude variation.
- Is the sample size (five sites) relevant for generalisation?
- What is the relevance of surface water temperature estimation since very often the deep layers can be highly different in temperature?
Line 273: there is a typo, water instead of watr
Author Response
We thank the reviewer for the positive comments and the opinion that our manuscript should be considered for publication. Please find the detailed response in the attachment, where we have considered, answered, and addressed each of the reviewer's suggestions, comments and concerns.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Kuhn and coauthors described the potential of Unmanned Aerial Vehicles (UAV) to understand patterns of stream thermal heterogeneity using a semi-automatic supervised approach. For the large part, the methodology is scientifically sound and there would be sufficient interest in the application of this technique to justify publication. I feel that the manuscript in its current form needs revision prior to publication.
The introduction is full and comprehensive, but some updated references related to other UAV survey technologies (i.e multispectral imagery, UAV bathymetry) are missing especially to be evaluated for better defining the water edge.
In my opinion, the "Materials and Methods" section could be better organized, especially for data processing and analysis. I think that is slightly confusing. I would like to propose a new figure showing this sequence of processes with a "Functional Block Diagram". I think that this methodological flowchart can help the readers. There are also a lot of acronyms used in the manuscript that I think are worth writing the full form to be easier for the reader to understand.
A thresholding near-infrared NIR to mask out the land using a multispectral camera could be discussed or evaluated.
Some figures are not in a publishable format I would also recommend geographic coordinates and grid for some of them and should be cited un the right point as for the location map.
A geodetic reference system could be indicated as like the position and influence of the use of different GCPs on the planimetric accuracy.
A conclusion should also be provided explaining how the results may improve our knowledge on this topic for instance and the discussion could be reduced.
Author Response
We thank the reviewer for considering our methodology scientifically sound and that there is interest for publication. Please, see the attachment pdf, where we address each of the reviewer's suggestions in detail.
Author Response File: Author Response.pdf
Reviewer 3 Report
See attached
Comments for author File: Comments.pdf
Author Response
We thank the reviewer for considering our manuscript appropriate and the results solid. Please, find the detailed response in the attachment, where we address each of the questions and comments from the reviewer.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
All suggested revisions have been successfully changed
Author Response
We thank the reviewer for the second review and positive feedback.
Reviewer 3 Report
The authors have addressed my comments and improved their manuscript. I only have some minor comments (please see attached).
Comments for author File: Comments.pdf
Author Response
We thank the reviewer for going through the manuscript once more and for making further suggestions to improve the clarity of the text. Please, see the attachment for the detailed response to each of the comments.
Author Response File: Author Response.pdf
