Comments from Reviewer 2:

“Stratospheric intrusion depth and its effect on surface cyclogenesis: An idealized PV
inversion experiment”
Authors: Barnes, Ndarana, Sprenger, and Landman
Recommendation: Minor Revision

Overview:
In this study, the authors perform a series of idealized experiments in which they invert QGPV
anomalies of various sizes, shapes, and vertical depths for their associated horizontal
circulations. These circulations are then used to identify QGPV configurations that are likely to
be more influential on surface cyclogenesis. The authors have done well to address my prior
comments on the manuscript. At the moment, the large share of my comments are textual in
nature, and offered to help improve the clarity and precision of the discussion. I have certainly
found the results to be interesting, and believe that the manuscript will be ready for publication
after a round of minor revision.

Minor, Specific, and Typographical Comments:
1. Introduction
L22: Rather than “down to”, consider “drawn from” as a potential substitution in the text.
L26: I think the ending of this sentence is a bit unclear. Is this sentence referring to the ideas of
PV invertibility or quasi-geostrophic theory? Consider a revision that improves the clarity of this
sentence.
L49: The first two sentences of this paragraph are a bit redundant. Consider a revision to
streamline the text a bit more.
L52–54: I find this particular sentence to be a bit vague and confusing. Could it be rewritten for
improved clarity? I view this sentence to be important for setting the stage for the forthcoming
analyses.
L59: I am still not sure why it should be expected that the effect should be different in the
Southern Hemisphere versus the Northern Hemisphere, especially in an idealized environment.
Consider corroborating the relevance of this statement more or simply keep the focus of the
study on systematically examining the characteristics of these intrusions from an idealized
perspective.

2. Methodology
L181: Consider revising the text to read as, “…is comprised of…”, for greater clarity.
Overall: I love the table to summarize the various experiments – a great resource while
evaluating the results.

3. Results
L212–213: I view this as a bit of a “chicken or the egg” type of description. I’m not sure I’m
comfortable with saying that COLs are generated by stratospheric intrusions of high PV, since
they are stratospheric intrusions of high PV. The generating mechanism, then, is what causes the
intrusion. Consider a revision to the text accordingly.
L216: I believe the figure reference should be to Fig. 6b in this line, rather than Fig. 7b. Figure
references appear to be off by 1 in many instances after this point in the manuscript.
L221: This quantity should be negative since we’re in the Southern Hemisphere.
L224: Consider referencing any specific figures from this prior work that may help direct the
reader to better verify this connection.
L239: I find the figure referencese to be unconventional. Consider using a more standard
a,b,c,d,e,etc. label for panels rather than mixing numbers and letters multiple times (i.e., avoid
7b2 and stick with 7a, 7b, etc.).
L292: For additional clarity, it may be worthwhile to emphasize that this text refers to the austral
summer.
L330: At the same time, the reduced tropospheric static stability in the high tropopause case can
also allow for the circulation induced by the upper-level PV anomaly to penetrate to lower
altitudes. I wonder if this is why you still see an effect of a lowered surface relative vorticity in
Fig. 10 for the high tropopause cases, but its muted due to the competing effects between the
penetration depth of the circulation and the height of the anomaly?
L341–342: These two sentences are a bit repetitive, could one be deleted for improved concision.
L369: This is largely semantics, but I view the use of the word, “intensity” throughout the
manuscript to be a bit confusing. Namely, when I see intensity I instantly think “magnitude”, but
here the discussion refers to radial depth. Consider reviewing the text in the manuscript to
improve the precision with which these changes to the PV anomalies are described. For example,
in L380, “magnitude intensity” are the same words, from my perspective. Could it be possible to
just keep reference to intensity in terms of anomaly magnitude and use radial depth or vertical
depth to refer to changes in the anomaly’s geometry?
L424–425: I believe this sentence refers to the wider PV anomaly, correct? If so, consider a
revision to the sentence clarifying this point.
L434: Typo: One “shallower” should be removed from this sentence.
L438–441: Consider providing a physical explanation for this (i.e., the horizontal scale of the
surface pressure distribution is larger for the broader anomalies, and thus the pressure gradient
does not necessarily get much stronger as you increase the radial width of the anomaly).

4. Discussion and Conclusions
L478: Consider emphasizing that you are referring to the height above ground level in this
sentence to promote further clarity.
L516: Consider adding the word, “environment”, after baroclinic in this sentence.
Figures and Tables:
Fig. 8: I remain a bit confused as to what the difference between minimum relative vorticity and
minimum cross-sectional relative vorticity is. Could this difference be more clearly identified
within the body of the text before this first figure is introduced? Apologies if it is described
earlier in the text and I missed it.

Please find attached the comments from Reviewer 3.

Dear Michael and co-authors,

One of the reviewers is happy with the revised manuscript, and the other reviewer has further minor suggestions. I would encourage you to address these and to resubmit the revised manuscript.

Kind regards,
Juliane