Dear Junfeng Wang and co-authors,

Thank you very much for your response to the comments and questions by two reviewers. I agree with both reviewers that the dataset is interesting and potentially an important contribution to our understanding of heterotrophic respiration in Arctic soils during different seasons. In particular, your question on how freeze-thaw processes affect CO2 production and emission is timely and relevant.

However, many important questions of both reviewers are not or only superficially addressed. Therefore, I encourage you to submit a major revision of the manuscript along with an updated point-by-point response to the reviewers. I just want to summarize some main questions/comments:

- Explain in detail, how freeze-thaw processes affect Rs in different stages.
- For the figures, please always make clear in figure captions or legend, which lines or points are observations and which are based on the models. Show both, model results and observation of Rs in the same plot.
- For the zero curtain-period: How many Rs observations in time do you have (2?) and is that enough to fit reliably the model? Do you need the model results for justifying the conclusions, or can you also justify them by observations alone?
- Fig 2: is the main peak (increase) in Rs before the ZC period?
- For the model evaluation, add root mean squared error analysis.
- Which temperature differences used for Q10 estimation?

Please, go back to the reviewer reports and have a look to each question and if you have addressed them carefully.

Sincerely Yours
Christian Beer

Dear Junfeng Wang and co-authors,

I would lilke to thank you a lot for all the improvements, updated and new figures and text. I can see that the paper develops in the right direction, the results are interesting and would merit publication in my view.

However, I do have some major comments that need to be addressed prior to a publication.

1) Fig 3. Please discuss further the overestimtion in spring and underestimation in autumn by the (temperature-driven) model.
2) Fig. 4: I assume the data are observations? Please, clarify in the caption.
3) Fig 6 and discussion 4.1.: Please, justify why these model results are important for our understanding of the processes. In Fig 4 we see that the model results are biased in spring and autumn, why are these results now used for understanding the processes and not the observations. For example, in Fig 6, AF stage, observations decrease and are not stable over the time. What do we learn here from the model results that are also only driven by temperature?

Minor: Please, add figure captions a,b,c etc. for clarity.

I am looking very much forward to receive a revised version of the MS and a detailed response to these comments.

Yours Sincerely
Christian Beer

Dear Junfeng Wang and colleagues,
Thank you for your detailed response and the improvements in the manuscript. I am happy to accept it now for publication in TC.
Sincerely Yours
Christian Beer