|Review of first revised version of the manuscript „Hydrological response of a peri-urban catchment exploiting conventional and unconventional rainfall observations: the case study of Lambro catchment“, submitted to HESS by Cazzangia et al.|
Summary: The authors have responded in detail to all reviewer comments and made changes to their analysis and the manuscript accordingly. Several relevant parts of the analysis were adjusted and redone. I very much appreciate that the authors took all my comments seriously. This is not always the case and there are easier ways to get a paper published nowadays. The changes that the authors introduced required a significant amount of work. Even though the results did only change in a negligible way, the analysis is now scientifically much more correct. Hence, the question, wether or not certain outcomes are a result of the processing and setup of the authors, is now clarified. Furthermore, there is now additional information in the manuscript that helps the readers to understand the details of how the CML data is used and what its potential and limitations are. I have some minor and technical comments for this revised manuscript. Thus, I suggest a small minor revision. According to my assessment, this revision would not need a further review.
First I want to comment on the authors’ response to my main comments from the first review:
1. CML processing: The additional details and the nicely made figures in the appendix are really helpful to understand how the processed CML data performs.
2. IDW method: Thank you for the effort to investigate the added benefit of the extended IDW method which you proposed in the initial manuscript. Following Occam's razor (the principle of parsimony) I fully agree with your decision to now use the simpler standard IDW method since its performance is the same as with the more complex extended IDW.
3. Overlap of calibration and validation period: It is much clearer now and I agree with your explanation that the partial overlap of calibration and validation is not problematic for the purpose of you study.
4. Model recalibration: It is good, in the sense that it is scientifically more correct, that the analysis is now also done using a recalibration with RG data. The fact that there are only negligible differences in the results seems to be a good indication that the initial model calibration was good and general enough.
Note that, in the following, my line numbers refer to the track-changes document.
Fig 4: Please clarify in the figure caption or in the legend of the figure that the numbers correspond to the individual events that you studied and that the markers are the individual CMLs (if I understood correctly).
L45: As far as I am informed the US radar network already used the dual-pol A(R)-Method for the operational product. Hence, this sentence should be reformulated since it suggest the QPE will benefit from dual-pol radar technology in the future, while it is actually already benefiting now.
L198: I do not find the description of the „hysteresis method“ in Nebuloni et al., 2020b. What does „hysteresis“ and „thresholded“ mean here?
L254: I found it confusing that this paragraph starts with this sentence because, as I found out after reading halfway through the paragraph, this paragraph is about the validation of the processing. It would be easier to read if the paragraph already starts with this topic.
L259: I do not really understand what the purpose of the two sentence is („To carry out…“). Also „fully fair comparison“ and „is seldom feasible“ do not sound correct to me.
L412: Why „120 samples (8 high rain rate events x 15 HRUs)“? I thought the analysis is carried out at hourly basis, hence, I expected much more data points. Please be more specific in the text.
Figure 13: I am not sure why I did not add this comment in my initial review, but would it makes sense to show the results from Fig 13 also separately for high and low rain rate events? Given that CMLs perform much better during the strong events, this should also have an effect here and could highlight the potential of CMLs for hydrological applications during strong rain events. This is just an idea, though.
L504: I do not understand what „…due to a mitigation effect“ means here.
L518: In my first review I suggested to add in „some subsections“. Now you have added one. In my opinion this results in a bit of a skewed structure of the discussion section with one long text on top and then this one subsection. Furthermore, I think it is very uncommon to add an unnumbered subsection here where 5.1 would be an appropriate numbering. I suggest to reconsider the structure of the subsection. Maybe you can add one or two more to split things up e.g. into a part about the data set size, a part about operational platforms and a part about ARF (just some ideas, not a definitive suggestion for the structure). In general, you should make a distinction between discussing the implications of your results and discussing potential future work.
L575: Since you remove the last part of the conclusion here, there is now a very abrupt end after the summary of your results. I suggest to add two to four „concluding“ sentences that briefly sum up the implications and potential of your work.
L14: I think the „of“ after „lacking“ is not correct and should be removed.
L216: Your reference Schleiss and Berne (2010) did not propose the WAA model you are describing. I think you mean Schleiss et al. (2013) https://doi.org/10.1109/LGRS.2012.2236074
L223: „for“ instead of „over“
L258: it should be „direct RG measurements“ instead of „RG direct measurements“
L383: :“…are very nearly the same… to the RG-based ones…“ is not a good formulation
L387: I think you do not need parenthesis around Delta_E
L421: „events“ instead of „event“
L423: it should be „much more scattered“