Dear authors,

first of all, please accept my appologies for the long time to decide on your manuscript. I did require some time to carefully look through the discussion and responses.

Two reviewers have given feedback on your manuscript. Both indicate that the topic is of great significance to the field of hydrology. They also put forward substantial criticism with regard to the approach and the presentation, and propose substantial changes to the manuscript. One reviewer proposed to consider rejection with invitation to resubmit.

I carefully went through the reviewers comments and your responses. I agree that the manuscript requires substantial changes, but in the general method will remain the same. I therefore decided to for major revision. In your revision please consider the following points.

Reviewer 1 gives a well structured and list of major points that should be attended to in the revision. I agree with them and I believe they also touch the major comments by Reviewer 2. In your response you have already clarified some of those points and indicated ways how you will address them in the manuscript. The technical points have been well addressed and I think for example the question on the approach to energy closure has been responded to in a satisfactory manner.

On the other hand some of the comments of the reviewers need in my eye deeper attention than your response currently concedes.
Both reviewers raise questions on the theory, underlying assumptions and the meaning of rhs. Reviewer 1 requests to move parts of the appendix to the main text, Reviewer 2 comments that they find it hard to follow the derivation. This is a clear call to move the theory completely to the main text. I strongly suggest you find a way to do so in a compact form.
In my reading much of the discussion between the authors and Reviewer 2 (and partly Reviewer 1) is due to a poor clarification of the system under consideration. For example, the citation from McColl et al. 2019 (cited in the response to Reviewer 2, 2. Major comment 1), originally from Raupach, 2001 (also cited there), refers to a „closed system“, which is clearly defined in their manuscript, but is not the same as the surface exchange considered in this present one. I suggest a clear statement of the closed (?) system considered, boundary conditions and their locations, applicable time scale. This at the same time would deliver the requested clarification of rhs.
You also conceded to enhance the discussion, as suggested by Reviewer 1, by exploring more deeply the results. In the new discussion please also incorporate a critical review of the method and findings, as requested be Reviewer 2, which frankly states the limitations of the method and data.

The revised manuscript will be sent to another round of reviews. Please support the review process by providing a manuscript with changes highlighted and a indicate the line numbers of the changed text passages in each of the responses.

I am looking forward to the revision,
Anke Hildebrandt

Dear authors,
thank you for your revision which has been assessed by the two reviewers.

Both reviewers find that given some further adjustments the paper is generally acceptable for publication. Could you please attend to those comments, and document the changes in a point by point response as well as in a new version with highlighted changes.

I may send the paper for a final check back to one or both of the reviewers. Please support the process by clearly documenting the decisions.

Thank you much, and I am looking forward to the new version!
Anke Hildebrandt

Dear authors,
thank you for implementing the last changes into the manuscript. I am pleased to accept your manuscript for publication in HESS. Please consider acknowledging the reviewers (although they are anonymous).
Sincerely,
Anke Hildebrandt