Decision on “From meteorological to hydrological drought using standardised indicators” by Barker et al.

Comments on points raised by Referee #1 (S. M. Vicente Serrano) and associated responses:
- First, I believe your responses to his comments are generally satisfying.
- As far as I know, the WMO guideline document on SPI referred to by the referee does not explicitly mention the gamma distribution. I would personally be interested in finding a document describing what is actually implemented in the SPI calculation software provided by WMO.
- Section 4.1: I agree with the authors on keeping SSI-n results with n > 1. Some sectors may be interested in knowing whether streamflow averaged over n months (for example during the recharge period) was below normal. The choice of looking only at SSI-1 in the remainder of the manuscript should however be justified, as mentioned in the authors’ response.
- In my opinion, Figures 6 and 7 are useful, for example for commenting the influence of long-term trends on drought event results. I would also appreciate a comment on the increased similarity of SPI-n and SSI-n when n increases.

Comments on points raised by Referee #2 and associated responses:
- The authors do not appear to have responded to one comment from the referee on the “performance of SPI and SSI during at least a few known historical drought events”. I am unsure of how one could assess the performance of such indicators (except by comparing to actual impacts, which is currently done by another HESSD paper), but the authors should prepare a response to this specific question.
- Like the referee, I still find Figures 3 and 5 hard to read (but I appreciate the efforts made after the first submission). It would be worth trying having larger dots, even if they overlap a bit.

Additional comments
- P12841 L20: “significant autocorrelation”: please indicate the confidence level
- I find that the choice of looking only at clusters 3 and 4 in the last part of the paper is not enough justified, especially for Figure 13.
- I would appreciate some comments on the robustness (or rather lack of) of the maximum severity/duration statistics over a rather short period for droughts (50 years). Indeed, severe drought events are quite rare and even more when large accumulation periods are considered. Moreover, no help to this lack of robustness can be found in the use of several stations as the spatial extent of a given event is generally larger than the UK (although there may be some differences between Scotland and the rest of the UK).

As a conclusion, I am confident that taking the reviewers’ comments into account may help in revising the manuscript for it subsequent publication in HESS.

Dear authors,

Thank you very much for submitting the revised version of your manuscript. I believe you have successfully addressed the referees' comments (and my own ones) and I can now accept it for publication in HESS.

There are only 2 technical points I would like to be addressed in order to make the manuscript even clearer:

- P11L9-10: “median severity increases” → “median values increases” (in order not to mistake the median maximum severity for the other drought characteristic: median severity).

- At several instances in the manuscript (and in some figures), you use “SPI-n duration”. I find it quite confusing because SPI-n represents the accumulation period with the highest correlation with SSI-1 (cf. P9L20-22), and it could be mistaken for the duration of meteorological drought events computed from SPI-n time series. So I would strongly recommend to change “SPI-n duration” to “SPI-n period” (for example, or simply “SPI-n”, although it could also been mistaken from the series itself) everywhere in the manuscript, including in the axes of Figures 11 to 13.

And I also spotted a typo:
- P8L20: “streamflowThe”

Best regards.