Interactive comment on “Comparison of nitrous oxide (N2O) analyzers for high-precision measurements of atmospheric mole fractions” by B. Lebegue et al

The air comparison could use more explanation. I think the authors should comment on how reliable these results are considering that some comparisons are based on measurements of dry air, while some are based on wet air with factory water vapor corrections, which, except for QC-TILDAS, you have shown are not adequate. You mentioned that the water vapor during the third period was < 1% (winter), but I suspect that water vapor was at least as high during the second period (May), yes? Thus, I’m surprised that the dispersion of ICOS-EP/FTIR results shown in Fig. 6 are so tight, considering that the comparison involved ambient (wet) air. From figure 4, we could expect positive bias of up to ∼0.5 ppb as water vapor approaches 2%. Thus, I would expect to see a tail on the negative side of the distributions in Fig. 6 for these instruments. Further, the slopes shown in Table 8 suggest real calibration differences. But these could also be related to water vapor, so how relevant are the slopes shown in Table 8? If you choose to report them, I suggest including an uncertainty and the N2O range measured. Alternatively, it might be better to replace Table 8 with a figure showing mole fraction differences as a function of time, or instrument X vs FTIR as a scatter plot with r-squared shown in each plot.