Dear Authors,

Thank you for providing detailed responses to the comments and suggestions offered by three reviewers.

All three reviewers recognized the importance of your study that aimed to develop a low-cost sensor system for measuring CH4 fluxes in chambers. While two reviewers offered short but very positive comments on your manuscript, the other reviewer raised a good number of technical issues. Given your thoughtful responses, I thought that you could address all the raised issues and concerns. Please go ahead to revise your manuscript based on all the comments offered by the three reviewers, paying a particular attention to “real-world” examples commented by the first reviewer and “optimum calibration procedures” including detailed comments of the third reviewer.

I would like to ask you to make all the changes easily identifiable in a marked-up manuscript and commensurately prepare a point-by-point reply to the comments offered by the three reviewers. Please specify the line numbers of the revised parts in your responses to the reviewer comments.

Sincerely,

Ji-Hyung Park
Associate Editor, Biogeosciences

Dear Authors,

Thank you for your careful revision of the manuscript considering all reviewer comments and suggestions. I am pleased to let you know that your manuscript can be published after technical corrections of the following:

- Abstract (Line 4) and many places thereafter: correct “mol fraction…” to “in the mole (or molar) fraction ranging from 2 – 700 ppm”
- Abstract (L 15): What do you mean by “These results open for…”? Something like “The proposed methods allow for…”?
- Introduction (L 19): Please clarify the term GWP100: for instance, “global warming potential per mass on a 100-year time horizon”
- R&d (L 241): Please clarify “the variability drifted by –0.24%/yr”.
- Conclusion (L 248): Do you mean “relative humidity (or humidity)…”?
- Fig. 1: Please add a 1:1 line to each plot as a reference for comparing measured and predicted values.
- Fig. S4: I would suggest that you use this as Fig. 3. You don’t need to save space. And this result would be very useful to emphasize the strong influence of humidity on field deployments of your proposed measurement system.
- I would also appreciate your careful proofreading to fix numerous errors in English grammar (e.g., L 21 “originates”; L 27 “is”,,,).

Sincerely,

Ji-Hyung Park
Associate Editor, Biogeosciences