|This manuscript is substantially improved, but needs minor revisions still.|
I think I understand from the author responses that the main theme of the study is that the time of ozone maximum is a useful diagnostic for the overall effects of aircraft NOx. This needs to be clarified in the text, as it is still not obvious. In particular there are still instances where the text refers to an early ozone maximum leading to or causing some effect. These all need to be more explicit that this is a correlation, not a causal link.
The text states that this diagnostic is computationally cheaper than running a full GCM, but doesn’t take this any further in explaining how the diagnostic could be used in practice.
Abstract, last sentence: This study doesn’t (but should) show how the findings can be used to towards a climate impact assessment.
Page 2, line 19: The discussion of the PMO needs to give a bit more detail.
Table 1: The caption should state where these regions are: ie. “in a ridge”, “to the west of a ridge”. PMO needs writing out in full in the caption.
Figure 1: The caption needs to state whether the time evolution of the chemical burdens in the lower plot is only along the parcel trajectories or a global change.
Page 3, line 10: The NOx cycling needs to be explained in a bit more detail. The lifetime of NOx is only around 2 days and is not washed out. Presumably the NOx cycles through NOy reservoirs (HNO3, PAN) and it is the HNO3 that is washed out.
Page 4, line 11: No, the earlier ozone does not cause a higher integrated O3, it is correlated with it.
Page 8, line 25: This wording needs to be more precise. Do these really have a “maximum at the end of the simulation” i.e. day 90? Or is it that they don’t have a maximum at all i.e. they are still increasing by day 90 – which is what you say a couple of sentences later.
Page 8, line 26: How high are these latitudes? Be specific.
Page 10, line 4: It may be better to be explicit “air parcels with an early O3 maximum are those that are transported to lower latitudes”. i.e. the early O3 maximum doesn’t cause the transport.
Page 10, line 6: better “air parcels with a late maximum are those that mostly stay …” i.e. the late maximum doesn’t cause them to stay.
Page 11, line 4: I don’t think (subgrid) deep convection affects the trajectories in your analysis.
Page 11, line10 – page 12, line 1: The thickness doesn’t determine a high pressure system as it is purely temperature. You need to use the geopotential heights to determine the synoptic conditions.
Figure 5, since thickness and temperature show more or less the same thing you don’t need both. I suggest using geopotential height instead for the top plot.
Page 18, line 22: DU refers to burden, not concentration.
Page 20, line 6: Better to say that high O3 maxima are only” found”, rather than “possible” You have shown a correlation, but not a causation.
Page 20, line 18-19: “allows” is too strong. You have shown that they are correlated, but not that one causes the other.