Impacts of the North Atlantic Oscillation on winter  precipitations and storm track variability in southeast  Canada and the northeast United States

Chartrand, Julien; Pausata, Francesco S. R.

doi:https://doi.org/10.5194/wcd-1-731-2020

Articles | Volume 1, issue 2

https://doi.org/10.5194/wcd-1-731-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/wcd-1-731-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 1, issue 2

Research article

|

30 Nov 2020

Research article |

| 30 Nov 2020

Impacts of the North Atlantic Oscillation on winter precipitations and storm track variability in southeast Canada and the northeast United States

Julien Chartrand and Francesco S. R. Pausata

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Final revised paper (published on 30 Nov 2020)
Preprint (discussion started on 19 May 2020)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Review of the manuscript', Anonymous Referee #1, 12 Jun 2020
- SC1: 'Short reply to reviewer #1', Julien Chartrand, 16 Jun 2020
RC2: 'wcd-2020-20 comments', Anonymous Referee #2, 09 Jul 2020
AC1: 'Final author's response to both reviewers (including revised manuscript)', Julien Chartrand, 10 Oct 2020

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Julien Chartrand on behalf of the Authors (10 Oct 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (13 Oct 2020) by Lukas Papritz

RR by Anonymous Referee #1 (23 Oct 2020)

For final publication, the manuscript should be

accepted as is

accepted subject to technical corrections

accepted subject to minor revisions

reconsidered after major revisions

I would be willing to review the revised paper, if the editor considers it necessary.

I am not willing to review the revised paper.

rejected

Suggestions for revision or reasons for rejection

In the revised version of the manuscript "Impacts of the North Atlantic Oscillation on Winter Precipitations and Storm Track Variability in Southeast Canada and Northeast US", the authors have substantially improved the both scientific significance and the organisation of the presented results. They were also able to resolve most of my concerns with the previous version of the manuscript. I am therefore recommending publication subject to the resolution of some remaining minor issues.

1) Most importantly, I am missing a climatology of how often "extreme" rainfall/snowfall events occur in the region in question. I suggest to add these climatologies, for example as additional panels to Figure 1.

2) I assume that the frequency of these events is on the order of one-to-several times during an average winter month. Should this be the case, please rephrase "extreme precipitation" by something like "intense precipitation event", because an event with a recurrence interval of one to a few weeks surely is not extreme.

3) Please normalize the track densities to detection per area [m^2] rather than by [deg^2]. With the current normalisation, cyclone track densities at higher latitudes are systematically underrepresented, and cyclone track densities would change if, for example, the pole of the coordinate system is rotated. I strongly recommend to use the units used in Neu et al. (2013) to simplify intercomparison.

4) Several occasions in sec. 3.3: I suggest to change "in storm tracking" -> "in the storm track".

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RR by Anonymous Referee #2 (02 Nov 2020)

ED: Publish subject to minor revisions (review by editor) (06 Nov 2020) by Lukas Papritz

Dear authors,

thank you for submitting a revised version of your manuscript and detailed responses. As you will see, the reviewers are overall satisfied with your revisions. However, reviewer 1 raises several important points that I'd ask you to address before the manuscript can be accepted for publication. In particular, he has concerns about the extremeness of the precipitation events and he points at a problem with the normalization of track densities.

From my own reading of the manuscript, I have a few additional requests as outlined below.

I would like to ask you to address the points by reviewer 1 and my own requests at your earliest convenience.

Best regards,
Lukas Papritz

Comments by the editor:

1. Cyclone tracking:

(-) State number of retained storms after filtering throughout the study period or per winter
(-) Is there a maximum distance threshold employed for matching minima?

2. Extreme precipitation: Using a fixed threshold of 10mm biases precipitation statistics to regions with higher climatological precipitation. It is no big surprise that difference fields look very patchy in Candian Arctic given the likely low climatological precipitation values. Furthermore, these low climatological values inflate the relative changes. You might consider masking areas that have too few occurrences of precipitation > 10mm.

3. As the manuscript relies heavily on a discussion of regional differences and correlations, I'd suggest to add geographical names such as "Nova Scotia"... to Fig. 2 as some of the readers may not be familiar with this region.

4. References:

(-) References to publications in preparation or under review are unfortunately not allowed in WCD. Please replace the reference on L137 to Chartrand and Thériault by another reference or adapt the sentence.

(-) Please update Hersbach et al. (2020) in the reference list.

5. Orthography and phrasing:

L16: ... there is as ... -> ... there are as ...
L59: phenomenon -> phenomena
L109: The phrasing is still confusing and suggests that a novel storm track algorithm has been developed. Please consider rephrasing this along the lines of "adapted the existing storm tracking algorithms by Murray and Simmonds (2001) and Hanley and Caballero (2012)"
L119: "Cyclones trajectories construction..." -> please rephrase adequately
L125: center -> centers
L131: cyclone geneses -> cyclogenesis events (?)
L139: Blockings -> Blocks
L140: Either "... influence on cyclogenesis and the storm track" or "... influence on cyclogenesis and cyclone trajectories"
L166: area that show -> area that shows
L181: area -> areas
L222: here and elsewhere: storm tracking -> storm tracks / cyclone tracks
L228: ... there is ... -> ... there are ...
L240: pattern -> patterns
L244: Please rephrase adequately: ... with statistical significance that covers a large area.
L262: delete the second occurence of "over"
Fig. 6: I think that (a) does not show relative but absolute differences.

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AR by Julien Chartrand on behalf of the Authors (16 Nov 2020) Author's response Manuscript

ED: Publish subject to technical corrections (18 Nov 2020) by Lukas Papritz

AR by Julien Chartrand on behalf of the Authors (18 Nov 2020) Author's response Manuscript

Short summary

This study explores the relationship between the North Atlantic Oscillation and the winter climate of eastern North America using reanalysis data. Results show that negative phases are linked with an increase in frequency of winter storms developing on the east coast of the United States, resulting in much heavier snowfall over the eastern United States. On the contrary, an increase in cyclone activity over southeastern Canada results in slightly heavier precipitation during positive phases.