Dear authors

Thank you for your revision of the manuscript. It significantly improved and gives now more information about the new technology you developed. I have only a couple of minor points that you need to address before publication.

P6,l20: Change the following statement: “The large standard deviation in CO is due to a sharp spike of several hundred ppb during three experiments, as seen in figure 3 (c). Figure 3 shows the time series of one of the experiments, The mole fractions during the three tests ranged from 394 to 417 ppm for CO2, 2009 to 2120 ppb for CH4 and 118 to 1657 ppb for CO.”

to

"Figure 3 shows the time series of one of the experiments, the mole fractions during the three tests ranged from 394 to 417 ppm for CO2, 2009 to 2120 ppb for CH4 and 118 to 1657 ppb for CO. The large standard deviation in CO is due to a sharp spike of several hundred ppb during three experiments, as seen in figure 3 (c)."

Figure 3: Explain the cause why the CH4 does not agree at around 14:39.

P10, l4-5: "Table 2 shows the mole fractions of CO2, CH4 and CO for the reference and fill gas, calibrated with respect to the WMO 2007, 2004A and 2004A scales for
CO2, CH4 5 and CO respectively"

change to

"Table 2 shows the mole fractions for the reference and fill gas, calibrated with respect to the WMO 2007, 2004A and 2004A scales for CO2, CH4 5 and CO respectively."

P11, l11: AirCore, t is...
P16, l1: change blue to red curves!!
P16, l3-5: The flight data are not mentioned (blue lines), add them. Why are the values significantly below the red lines despite hovering at 60 meters? As I understand from Figure 10, the flight tracks transects 60 meters but does not hover there. Therefore, change the verb hover to transect (transecting) in the Figure legend of 8.

Figure 8, 9: I would keep the red line for 60 meters as for figure 8. Take the blue line for 40 meters instead.
Figures: For any Figure, e.g. Figure 10. Vertical
dot after number and start with capital letter.
P22, l19: I would list them according to the following description numbering.
3.5.3 add Talyor dispersion, i.e. Diffusion and Taylor dispersion
P24, l8: with the major contribution from the Picarro CRDS smearing effect.
P24, l9: are instead of is
P25,l11: lower case for methane

With best regards

Markus Leuenberger