Dear authors:

Thank you for making inspiring discussion with the referees.
Your manuscript received two referee comments and one short comment, each of which found merits in your manuscript. One referee felt insufficiency in scientific significance, perhaps because of the apparent overlapping with your previous work, while another referee indicated that it has ‘good’ scientific significance. I studied your responses to the referee’s concerns and found that you provided sufficient rebuttals. However, I need to ask the referees whether your response is sufficient or not. Both referees evaluated that this manuscript has ‘good’ presentation quality, and fair to good scientific quality. Based on these evaluations, I conclude that the manuscript needs major revision to be considered as a candidate of publication.

Dear authors:
Thank you for providing the revised manuscript, which is adequate in most points.
One referee provided a small suggestion, which looks easily answerable for you.
I am looking forward to receiving your response.

Dear authors:
Thank you for providing the revised manuscript. I confirmed that you made a necessary revision on the basis of the referee comment. I looked over the manuscript and, finally, would like to recommend it to be accepted for publication after technical corrections.

Technical correction:
Please look over references again. For example,
- Line 504: Please do not use capital for all characters of author names.
- Line 521: van Emmerik et al. (2018) was published as an article from Biogeosciences (15, 6439–6449).
- Line 530: please do not capitalize the first characters of title words except for the first one