Thank you for submitting a well written and comprehensive manuscript, and for responding thoroughly to the reviewer comments. Please make the following minor technical corrections to the manuscript prior to final submission and copy-editing.

1) p. 24, L794: Is "alternating" (switching back and forth) the most appropriate word here, or would "variable" be a better choice?
2) I don't find the photograph of the instrument innards (Fig. 2) particularly informative. Would you consider combining Figs. S2 and S3 into a single figure and swapping it with Fig. 2? Since the content can still be found in the Supplement, I'll leave this to your decision.
3) The references have several problems typical of reference manager-type software:
a) Several of the titles for journal articles are capitalized (e.g., Agranovski, Calvo, Fennelly, . . . .). Please follow Copernicus guidelines.
b) Should Van Grondelle be with the "V"s?
c) Check the order of the Kaye et al. and Robinson et al. references.
d) Hinds et al., please capitalize "Airborne"
e) Doi numbers are sometimes used and sometimes not. Please find missing doi numbers if possible and use them.
f) Sodeau and Connor need volume/page/doi info.