the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 26 Mar 2024
Overview: Quasi-Lagrangian observations of Arctic air mass transformations – Introduction and initial results of the HALO–(AC)3 aircraft campaign
Abstract. The global warming is amplified in the Arctic. To collect data that help to constrain weather and climate models, which often do not realistically represent the enhanced Arctic warming, the HALO-(AC)³ aircraft campaign was conducted in March and April 2022 over the Norwegian and Greenland Seas, the Fram Strait, and the central Arctic Ocean. Observations were made over areas of open ocean, the marginal sea ice zone, and the central Arctic sea ice. Two low-flying and one long-range, high-altitude research aircraft have been employed. Whenever possible, the three aircraft were flown in collocated formation. The campaign focused on one specific challenge posed by the models: The reasonable representation of transformations of air masses during their meridional transport into (northward by moist and warm air intrusions, WAIs) and out of (southward via marine cold air outbreaks, CAOs) the Arctic. To observe the air mass transformations, a quasi-Lagrangian flight strategy using trajectory calculations was realized enabling to sample the moving air mass parcels twice along their trajectories. Eight distinct WAI and 12 CAO cases were probed extensively. From the quasi-Lagrangian measurements, we have derived the diabatic heating and moistening of the moving air masses during CAOs and WAIs, the development of cloud macrophysical and microphysical properties along the southward pathways of the air masses during CAOs, and the moisture budget of WAIs. As an example result, we have obtained typical values of the surface-driven diabatic heating between 1–3 K h-1 and of the near-surface moistening between 0.05–0.3 g kg-1 h-1 within the lowest about 0.5 km. From the observations of WAIs, a weak diabatic cooling of up to 0.4 K h-1 and a moisture loss of up to 0.1 g kg-1 h-1 from the ground to about 5 km altitude were derived. In addition, we discuss the frequency of occurrence of the different thermodynamic phases of Arctic low-level clouds, the interaction of Arctic cirrus with sea ice, water vapor, and aerosol particles, and the characteristic microphysical and chemical properties of Arctic aerosol particles. Finally, we provide proof of a concept to measure mesoscale divergence and subsidence in the Arctic using data from dropsondes released during circular flight patterns.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
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- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2024-783', Anonymous Referee #1, 30 Apr 2024
Review of “Overview: Quasi-Lagrangian observations of Arctic air mass transformations – Introduction and initial results of the HALO–(AC)3 aircraft campaign” by Wendisch et al., for publication in Atmospheric Chemistry and Physics
Summary
This paper provides an overview of the recent HALO-(AC)3 aircraft campaign highlighting the flight plans/strategy, measurements, and various measurement/sampling techniques of Arctic air masses. Some of the novelties of this study include quasi-Lagrangian measurements from eight warm-air intrusion (WAI) and twelve cold-air outbreak (CAO) cases, derived surface heating/cooling and moistening/drying estimates, comprehensive aerosol/CCN data, and estimates of mesoscale divergence using dropsondes released during circular flight patterns. The abstract is very well written, concise, and clearly conveys the novelties and (initial) results of the AC3 campaign. The quasi-lagrangian sampling strategy is very clearly defined, thought out, and easy to follow in the text/results. The section on Arctic clouds nicely highlights cloud phase as a function of the underlying surface (open water versus sea ice) as well as a simultaneous retrieval of effective radius for both ice crystals and liquid drops. These results, in my view, appropriately highlight and contextualize the various datasets as well as set the table for a number of planned (and likely interdisciplinary) analyses across a wide array of Arctic climate science sub-disciplines. Aside from a couple of very minor comments (indicated in the Specific Comments) and with a few of the figures being quite “busy” with lines and markers, every figure – in my view – is justified in its content with each figure adding very clear and rich context to the paper. Another strength of this manuscript is that, given volume of data and analysis in this manuscript, all sources of uncertainty (e.g., LWP and snowfall) are well characterized and quantified.
This is a commendable effort by all authors and contributors. For a very lengthy manuscript with 17 figures and 3 appendices, this was a very fun read with a lot of concise, “to-the-point” information that many sub-disciplines within the Arctic science community will be eager to read. I liken this manuscript to a fine 7-course dinner: it may take a while before you’re finished, but every course delivers masterfully crafted dishes by world-class chefs with each dish delivering a palette of flavors certain to whet every appetite in the Arctic climate community. The manuscript in its present form is perfect in the sense that it captures just the right amount of detail (in my view) for an overview paper. While I have a number of very specific comments that would improve clarity in a few spots, they are extremely minor and can be addressed quickly without the need for a second review. I have no general concerns/comments for this manuscript, and overall, I believe this manuscript is publishable in its present form to Atmospheric Chemistry and Physics.
I look forward to many more in-depth studies following and building upon the excellent work presented in this manuscript.
Specific Comments
L23-24: “... was more than 1.5 K warmer than during pre-industrial times” though it’s stated “Data published by the Copernicus Climate Change Service show...”, this statement needs a citable reference.
L24: “numerous feedback mechanisms in the Earth’s climate system” it would be good to list 2-3 or so of these feedback mechanisms here.
L44: A reference or two here would be good.
L105: This is a very lengthy introduction, but a necessary one as each paragraph here has a clear focus and motivation for the AC3 campaign.
L124: Add latitude/longitude coordinates for Kiruna and Longyearbyen here.
L134: Add latitude/longitude coordinates for Ny-Ålesund.
Section 2, like the introduction, is very well structured and written.
L171: Casual readers may not fully understand what a “Lagrangian” frame of reference is and how it ties into the sampling strategy described in this paragraph. A sentence to open up this paragraph describing what “Lagrangian” is, in my view, would lead the rest of this paragraph better and make the sampling strategy clearer to the reader in its objective.
L174: “Because of their...” I would lead this sentence with “For example, ...” as this would more clearly lead the reader into a discussion of balloon-related drawbacks described in the previous sentence.
Figure 2 Caption: Recommend changing “enables to observe the changes” to “enables observational changes”
L248: I am slightly confused by the writing here – what do you mean by a “quality of possibilities”? I think “provides unprecedented quantity of possibilities” would work here.
Figure 5: This is a very well-constructed figure that clearly contrasts CAOs with WAIs.
L305: How exactly is the “ice growth process” inferred or done using measurements here?
L306: Can you point to or reference where “we also detect stronger riming”?
Figure 6: Very picky comment here... “weak” should be capitalized in the Figure Title.
L317-319: Very interesting result!
Figure 7: I love the setup of this figure – it is definitely one of the most informative figures I’ve ever seen relating ice index and distance from the ice edge to actual cloud morphology. I hope to see versions of this figure in your future papers.
Figure 8 caption: Is it really necessary to call this a “Shapiro-Keyser cyclone” here? I think it would be better if this were referenced (including the citation) in the main text rather than the figure caption.
L374 and Figure 10 caption: One of the other prevailing cloud phase/microphysics algorithms for ground-based cloud remote sensors follows the widely-used Shupe et al. (2008, and references therein). I think it would be useful for the Arctic cloud/climate community to comment on how your algorithm compares with the Shupe et al. algorithm (and perhaps discuss how a comparison of these algorithms might be done in a future AC3-related study which would also be very interesting!).
Shupe, M. D., and Coauthors, 2008: A Focus On Mixed-Phase Clouds. Bull. Amer. Meteor. Soc., 89, 1549–1562, https://doi.org/10.1175/2008BAMS2378.1.
L382: Just say “Future studies” rather than “near future studies”.
L390: Following my previous comment for L374, this might be a good spot to discuss potential differences in these algorithms.
L430: How typical are RHi values of 140%? Might be good to add a reference or two here for comparison sake.
L455-456: I’d merge these two sentences.
L512-513: I agree with this conclusion.
Review Criteria
- Does the paper address relevant scientific questions within the scope of ACP? Yes, all objectives and questions fit within the scope of ACP.
- Does the paper present novel concepts, ideas, tools, or data? Yes, many ideas/concepts and tools are novel.
- Are substantial conclusions reached? Yes, for an overview paper, the initial results and findings represent substantial conclusions.
- Are the scientific methods and assumptions valid and clearly outlined? Yes.
- Are the results sufficient to support the interpretations and conclusions? Yes, and all interpretations/conclusions are well characterized in terms of potential sources of uncertainty or other limitations.
- Is the description of experiments and calculations sufficiently complete and precise to allow their reproduction by fellow scientists (traceability of results)? Yes.
- Do the authors give proper credit to related work and clearly indicate their own new/original contribution? Yes.
- Does the title clearly reflect the contents of the paper? Yes.
- Does the abstract provide a concise and complete summary? Yes.
- Is the overall presentation well-structured and clear? Yes, the presentation is of extremely high quality and very clear.
- Is the language fluent and precise? Yes, the language is very clear, fluent and precise.
- Are mathematical formulae, symbols, abbreviations, and units correctly defined and used? Yes, all mathematical formulae, etc. are correctly defined and used.
- Should any parts of the paper (text, formulae, figures, tables) be clarified, reduced, combined, or eliminated? No, I believe the length of all parts of the paper are appropriate and/or sufficient in length.
- Are the number and quality of references appropriate? Yes. The number of figures and references are a bit on the high side, but understandably so as this is an overview paper of a major, multi-platform field campaign.
- Is the amount and quality of supplementary material appropriate? Yes, the supplementary material adds rich quality and material to the manuscript.
Citation: https://doi.org/10.5194/egusphere-2024-783-RC1 -
AC1: 'Reply on RC1', Manfred Wendisch, 12 Jun 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-783/egusphere-2024-783-AC1-supplement.pdf
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RC2: 'Comment on egusphere-2024-783', Anonymous Referee #2, 23 May 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-783/egusphere-2024-783-RC2-supplement.pdf
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AC2: 'Reply on RC2', Manfred Wendisch, 12 Jun 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-783/egusphere-2024-783-AC2-supplement.pdf
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AC2: 'Reply on RC2', Manfred Wendisch, 12 Jun 2024
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2024-783', Anonymous Referee #1, 30 Apr 2024
Review of “Overview: Quasi-Lagrangian observations of Arctic air mass transformations – Introduction and initial results of the HALO–(AC)3 aircraft campaign” by Wendisch et al., for publication in Atmospheric Chemistry and Physics
Summary
This paper provides an overview of the recent HALO-(AC)3 aircraft campaign highlighting the flight plans/strategy, measurements, and various measurement/sampling techniques of Arctic air masses. Some of the novelties of this study include quasi-Lagrangian measurements from eight warm-air intrusion (WAI) and twelve cold-air outbreak (CAO) cases, derived surface heating/cooling and moistening/drying estimates, comprehensive aerosol/CCN data, and estimates of mesoscale divergence using dropsondes released during circular flight patterns. The abstract is very well written, concise, and clearly conveys the novelties and (initial) results of the AC3 campaign. The quasi-lagrangian sampling strategy is very clearly defined, thought out, and easy to follow in the text/results. The section on Arctic clouds nicely highlights cloud phase as a function of the underlying surface (open water versus sea ice) as well as a simultaneous retrieval of effective radius for both ice crystals and liquid drops. These results, in my view, appropriately highlight and contextualize the various datasets as well as set the table for a number of planned (and likely interdisciplinary) analyses across a wide array of Arctic climate science sub-disciplines. Aside from a couple of very minor comments (indicated in the Specific Comments) and with a few of the figures being quite “busy” with lines and markers, every figure – in my view – is justified in its content with each figure adding very clear and rich context to the paper. Another strength of this manuscript is that, given volume of data and analysis in this manuscript, all sources of uncertainty (e.g., LWP and snowfall) are well characterized and quantified.
This is a commendable effort by all authors and contributors. For a very lengthy manuscript with 17 figures and 3 appendices, this was a very fun read with a lot of concise, “to-the-point” information that many sub-disciplines within the Arctic science community will be eager to read. I liken this manuscript to a fine 7-course dinner: it may take a while before you’re finished, but every course delivers masterfully crafted dishes by world-class chefs with each dish delivering a palette of flavors certain to whet every appetite in the Arctic climate community. The manuscript in its present form is perfect in the sense that it captures just the right amount of detail (in my view) for an overview paper. While I have a number of very specific comments that would improve clarity in a few spots, they are extremely minor and can be addressed quickly without the need for a second review. I have no general concerns/comments for this manuscript, and overall, I believe this manuscript is publishable in its present form to Atmospheric Chemistry and Physics.
I look forward to many more in-depth studies following and building upon the excellent work presented in this manuscript.
Specific Comments
L23-24: “... was more than 1.5 K warmer than during pre-industrial times” though it’s stated “Data published by the Copernicus Climate Change Service show...”, this statement needs a citable reference.
L24: “numerous feedback mechanisms in the Earth’s climate system” it would be good to list 2-3 or so of these feedback mechanisms here.
L44: A reference or two here would be good.
L105: This is a very lengthy introduction, but a necessary one as each paragraph here has a clear focus and motivation for the AC3 campaign.
L124: Add latitude/longitude coordinates for Kiruna and Longyearbyen here.
L134: Add latitude/longitude coordinates for Ny-Ålesund.
Section 2, like the introduction, is very well structured and written.
L171: Casual readers may not fully understand what a “Lagrangian” frame of reference is and how it ties into the sampling strategy described in this paragraph. A sentence to open up this paragraph describing what “Lagrangian” is, in my view, would lead the rest of this paragraph better and make the sampling strategy clearer to the reader in its objective.
L174: “Because of their...” I would lead this sentence with “For example, ...” as this would more clearly lead the reader into a discussion of balloon-related drawbacks described in the previous sentence.
Figure 2 Caption: Recommend changing “enables to observe the changes” to “enables observational changes”
L248: I am slightly confused by the writing here – what do you mean by a “quality of possibilities”? I think “provides unprecedented quantity of possibilities” would work here.
Figure 5: This is a very well-constructed figure that clearly contrasts CAOs with WAIs.
L305: How exactly is the “ice growth process” inferred or done using measurements here?
L306: Can you point to or reference where “we also detect stronger riming”?
Figure 6: Very picky comment here... “weak” should be capitalized in the Figure Title.
L317-319: Very interesting result!
Figure 7: I love the setup of this figure – it is definitely one of the most informative figures I’ve ever seen relating ice index and distance from the ice edge to actual cloud morphology. I hope to see versions of this figure in your future papers.
Figure 8 caption: Is it really necessary to call this a “Shapiro-Keyser cyclone” here? I think it would be better if this were referenced (including the citation) in the main text rather than the figure caption.
L374 and Figure 10 caption: One of the other prevailing cloud phase/microphysics algorithms for ground-based cloud remote sensors follows the widely-used Shupe et al. (2008, and references therein). I think it would be useful for the Arctic cloud/climate community to comment on how your algorithm compares with the Shupe et al. algorithm (and perhaps discuss how a comparison of these algorithms might be done in a future AC3-related study which would also be very interesting!).
Shupe, M. D., and Coauthors, 2008: A Focus On Mixed-Phase Clouds. Bull. Amer. Meteor. Soc., 89, 1549–1562, https://doi.org/10.1175/2008BAMS2378.1.
L382: Just say “Future studies” rather than “near future studies”.
L390: Following my previous comment for L374, this might be a good spot to discuss potential differences in these algorithms.
L430: How typical are RHi values of 140%? Might be good to add a reference or two here for comparison sake.
L455-456: I’d merge these two sentences.
L512-513: I agree with this conclusion.
Review Criteria
- Does the paper address relevant scientific questions within the scope of ACP? Yes, all objectives and questions fit within the scope of ACP.
- Does the paper present novel concepts, ideas, tools, or data? Yes, many ideas/concepts and tools are novel.
- Are substantial conclusions reached? Yes, for an overview paper, the initial results and findings represent substantial conclusions.
- Are the scientific methods and assumptions valid and clearly outlined? Yes.
- Are the results sufficient to support the interpretations and conclusions? Yes, and all interpretations/conclusions are well characterized in terms of potential sources of uncertainty or other limitations.
- Is the description of experiments and calculations sufficiently complete and precise to allow their reproduction by fellow scientists (traceability of results)? Yes.
- Do the authors give proper credit to related work and clearly indicate their own new/original contribution? Yes.
- Does the title clearly reflect the contents of the paper? Yes.
- Does the abstract provide a concise and complete summary? Yes.
- Is the overall presentation well-structured and clear? Yes, the presentation is of extremely high quality and very clear.
- Is the language fluent and precise? Yes, the language is very clear, fluent and precise.
- Are mathematical formulae, symbols, abbreviations, and units correctly defined and used? Yes, all mathematical formulae, etc. are correctly defined and used.
- Should any parts of the paper (text, formulae, figures, tables) be clarified, reduced, combined, or eliminated? No, I believe the length of all parts of the paper are appropriate and/or sufficient in length.
- Are the number and quality of references appropriate? Yes. The number of figures and references are a bit on the high side, but understandably so as this is an overview paper of a major, multi-platform field campaign.
- Is the amount and quality of supplementary material appropriate? Yes, the supplementary material adds rich quality and material to the manuscript.
Citation: https://doi.org/10.5194/egusphere-2024-783-RC1 -
AC1: 'Reply on RC1', Manfred Wendisch, 12 Jun 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-783/egusphere-2024-783-AC1-supplement.pdf
-
RC2: 'Comment on egusphere-2024-783', Anonymous Referee #2, 23 May 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-783/egusphere-2024-783-RC2-supplement.pdf
-
AC2: 'Reply on RC2', Manfred Wendisch, 12 Jun 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-783/egusphere-2024-783-AC2-supplement.pdf
-
AC2: 'Reply on RC2', Manfred Wendisch, 12 Jun 2024
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Cited
4 citations as recorded by crossref.
- Thermodynamic and cloud evolution in a cold-air outbreak during HALO-(AC)3: quasi-Lagrangian observations compared to the ERA5 and CARRA reanalyses B. Kirbus et al. 10.5194/acp-24-3883-2024
- Contrasting extremely warm and long-lasting cold air anomalies in the North Atlantic sector of the Arctic during the HALO-(𝒜 𝒞)3 campaign A. Walbröl et al. 10.5194/acp-24-8007-2024
- Lidar–radar synergistic method to retrieve ice, supercooled water and mixed-phase cloud properties C. Aubry et al. 10.5194/amt-17-3863-2024
- Evaluating the representation of Arctic cirrus solar radiative effects in the Integrated Forecasting System with airborne measurements J. Röttenbacher et al. 10.5194/acp-24-8085-2024
Manfred Wendisch
Susanne Crewell
André Ehrlich
Andreas Herber
Benjamin Kirbus
Christof Lüpkes
Mario Mech
Steven J. Abel
Elisa F. Akansu
Felix Ament
Clémantyne Aubry
Sebastian Becker
Stephan Borrmann
Heiko Bozem
Marlen Brückner
Hans-Christian Clemen
Sandro Dahlke
Georgios Dekoutsidis
Julien Delanoë
Elena De La Torre Castro
Henning Dorff
Regis Dupuy
Oliver Eppers
Florian Ewald
Geet George
Irina V. Gorodetskaya
Sarah Grawe
Silke Groß
Jörg Hartmann
Silvia Henning
Lutz Hirsch
Evelyn Jäkel
Philipp Joppe
Olivier Jourdan
Zsofia Jurányi
Michail Karalis
Mona Kellermann
Marcus Klingebiel
Michael Lonardi
Johannes Lucke
Anna Luebke
Maximilian Maahn
Nina Maherndl
Marion Maturilli
Bernhard Mayer
Johanna Mayer
Stephan Mertes
Janosch Michaelis
Michel Michalkov
Guillaume Mioche
Manuel Moser
Hanno Müller
Roel Neggers
Davide Ori
Daria Paul
Fiona Paulus
Christian Pilz
Felix Pithan
Mira Pöhlker
Veronika Pörtge
Maximilian Ringel
Nils Risse
Gregory C. Roberts
Sophie Rosenburg
Johannes Röttenbacher
Janna Rückert
Michael Schäfer
Jonas Schäfer
Vera Schemannn
Imke Schirmacher
Jörg Schmidt
Sebastian Schmidt
Johannes Schneider
Sabrina Schnitt
Anja Schwarz
Holger Siebert
Harald Sodemann
Tim Sperzel
Gunnar Spreen
Bjorn Stevens
Frank Stratmann
Gunilla Svensson
Christian Tatzelt
Thomas Tuch
Timo Vihma
Christiane Voigt
Lea Volkmer
Andreas Walbröl
Anna Weber
Birgit Wehner
Bruno Wetzel
Martin Wirth
Tobias Zinner
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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