Dear Authors
Thanks for your detailed replies to the reviewer comments, and I hope you found the comments useful to your paper. Based on my assessment of the discussion and the suggested changes you have indicated in the replies, I would like to invite you to upload a revision of the paper that addresses the concerns/issues raised during the discussion. The reviewers will get an additional opportunity to comment on the revised version so please outline in your new submission the changes that have been made, so the issues within the discussion can be easily referred to.
Many thanks
Matt Hipsey

Dear authors,
Many thanks for your substantially improved version of your manuscript. The paper has been re-reviewed with positive assessments and an acknowledgement this is a useful and timely contribution. I have a few final comments for you to address prior to final publication, as described below.
Kind Regards
Matt Hipsey

Sentence 2 of the Introduction – can this reference be updated? The 2008 report is now referring to simulations from a decade ago

Page 2Line 24 – leaf area index mentioned but not abbreviated; in the abstract LAI abbreviation is used but not defined .. please check use throughout of acronyms

Currently the paper sections 2-5 are methods and then section 6 serves as both results and discussion. It therefore remains difficult to link specific aims, approaches and findings through the manuscript. Currently at the end of Page 3 a general aim is given, and then some methodological/approach type statements. I believe this could be strengthened to better allow the reader to link specific objectives in the introduction to approach and then to findings. For example, ideally sub-headings in Section 6 would map to specific aims/objectives made clear at the end of the introduction. This ensures the reader can more easily navigate the different aspects of the paper from start to finish.

Section 4.2.2 – the abstract and introduction makes reference to remote sensing as a key component of the study, yet the sub-headings don’t make clear where this aspect of the study is described. I assume it is this section 4.2.2 – can its sub-heading be made more clear/specific? Or perhaps an introductory paragraph in Section 4.2 to overview/summarise the range of data used to paint a clear picture early on?

Section 5 – I think this section is currently not ideal as a major heading – can it instead be included in Section 3 or 4 with some minor changes to sub-heading titles? Also, because this section is attached at the end of the model and data sections, it remains unclear what is being evaluated by these metrics. It is stated that “The performance of the TSEB model and possible refinements for Arctic tundra was evaluated …” … but at this point of the paper it is unclear what this means. Can you please re-word and better link this section to specific variables being modelled/measured, and how it is used to compare model approaches – this may be helped if it is incorporated in section 3 or 4.

Section 6.3 – I have followed up with Reviewer 2 about RC_12, relating to closure of the energy balance. After consultation, I believe this section is still not satisfactory in making clear the issue of error accumulating in the residual term. Because we do not understand where the error is coming from (instrument, advection, footprint, radiation, soil heat flux, etc.) then it is not appropriate to try and force the energy balance to close.  Calculating LE as a residual puts all of the error in the LE term which is unacceptable and could be misleading.  Due to the uncertainty in the source of error and the fact that there may be biases in any particular term in the energy balance, it is not appropriate to force energy balance closure either.  The conservative approach is to use the original data and not force to energy balance to close. This section should be updated and improved bearing this in mind.

Acknowledgements – Please consider acknowledging the help and inputs by the reviewers during the discussion process (should you believe it was helpful in improving the manuscript!)

Dear Authors
Thankyou for your final revision of this paper and I am pleased to accept this version - I think this will make an excellent contribution to HESS and be useful to the surface energy balance modelling community.
Kind Regards
Matt Hipsey