Vertically-resolved source contributions to climate-relevant aerosol properties in Southern Greenlandic fjord systems

Alden, Joanna; Bergner, Nora; Heutte, Benjamin; Favre, Lionel; Surdu, Mihnea; Weng, Julian; Augugliaro, Marta; Winiger, Patrik; Dönmez, Berkay; Pohorsky, Roman; Calmer, Radiance; Chatterjee, Carmelle; Violaki, Kalliopi; Nenes, Athanasios; Gregor, Luke; Henning, Silvia; Schmale, Julia

doi:10.5194/acp-26-7165-2026

Articles | Volume 26, issue 10

https://doi.org/10.5194/acp-26-7165-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-26-7165-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 26, issue 10

Research article

|

26 May 2026

Research article |

| 26 May 2026

Vertically-resolved source contributions to climate-relevant aerosol properties in Southern Greenlandic fjord systems

Joanna Alden, Nora Bergner, Benjamin Heutte, Lionel Favre, Mihnea Surdu, Julian Weng, Marta Augugliaro, Patrik Winiger, Berkay Dönmez, Roman Pohorsky, Radiance Calmer, Carmelle Chatterjee, Kalliopi Violaki, Athanasios Nenes, Luke Gregor, Silvia Henning, and Julia Schmale

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Preprint (discussion started on 27 Nov 2025)
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Interactive discussion

Status: closed

RC1: 'Comment on egusphere-2025-5710', Anonymous Referee #1, 12 Feb 2026

General scientific comment:
The manuscript presents interesting and valid results on aerosol properties measured at a Southern Greenlandic location. The manuscript is marked by a high quality of written English language. Major efforts were carried out in doing an extensive field campaign also establishing a ground-based station including even remote sensing techniques at the remote site. In addition, tethered balloon measurements were performed. The work presents a rare and comprehensive dataset worth publishing while investigating different air mass types that were classified according to the prevailing major observations.
Minor revisions are suggested to improve the manuscript addressing the comments below. One major point is that I recommend not to discuss figures and tables from the Supplementary Information in the main text. The manuscript should focus on major findings presented in the main manuscript. Readers that want to get e.g. more information about additional cases should go to the SI and find all relevant information there. One sentence referring to that information in the main manuscript should be enough.
Detailed scientific comments (main manuscript):
2.1 Sampling site
Page 4, line 95:
Comment: Could you provide the distance of the mountains to Narsaq?
2.2 Ground-based measurements
Page 5, line 109:
Comment: Please say what you mean with interstitial, does it mean the sizing (PM1/TSP) was decisive if interstitial or total was measured, then please say so.
General comment:
For a better overview, I suggest to place Figure S1 from the supplementary information to the main manuscript.
2.2.1 Particle number concentration and size distribution
Page 6, line 118:
Comment: Has the SMPS been size calibrated or a comparison to total particle number has been checked against another particle counter? If so, please state.
2.2.2 Aerosol absorption and scattering coefficients
Page 8, line 151:
Comment: Can you say something about the calibration of the Aurora with span gas and zero measurements?
2.2.3 Cloud condensation nuclei number concentrations
Page 8, line 156:
Comment: Has a calibration based on ammonium sulphate or similar salt been performed? If so, please state.
2.4 Data processing, pollution flagging, and environmental condition categorization
Page 10, line 225 - 240:
Comment: I am missing more hard criteria of category nr. 1 and nr. 3. I understand that category nr. 2 will be explained later in the manuscript and nr. 4 has a subjective character. But for category nr. 3 you must have some mathematical or other criteria to identify the events? Can you please elaborate more clearly on this?
Page 10, line 242:
Comment: Please check comment in German language in this line!
Page 11, Figure 2:
Comment: I recommend to place Figure 2 rather more in the supplementary information.
3.2 Background versus fresh pollution regimes
Page 19, line 362:
Comment: Do you mean that BG_C1 includes regional particle formation and growth events that are not identified and classified as new particle growth events (GE)?
Page 19, line 371:
Comment. I agree that pollution clusters are different in magnitude and variability, but that does also count for the middle cluster of the background. Do you have an explanation for that?
Page 20, line 381:
Proposal: … of specific aerosol properties …
3.3 Particle growth events
Page 21, line 398:
Comment: You mean (Fig. 3)!
Page 21, Figure 7:
Comment: What do you mean by normalised?
Page 22, line 420:
Comment: Can you in general exclude any anthropogenic sources in this region which you calculate to be the start area of the event? The conclusion is quite fascinating that the fjord must be the source!
Page 23, line 440:
Comment: Please check comment in German language in this line!
Page 23, line 442:
Comment: Honestly, I clearly see also a trimodal distribution for sGE _C1 cluster. In any case, this does not change your conclusions on the evolution of the whole event! I recommend to refit the data.
Page23/24, Figure9/10:
Comment: I feel it is a bit complicated to follow the figures and also your conclusions. I suggest to combine Figure 9 and Figure 10. It would be great to see the evolution of PNSD in terms of clusters or averaged distributions of the ground PNSD based on the vertical PNSD. I understand here that the clustering is done separately for both instruments. This makes in principle sense, but does not show all the time similar time periods when you compare the distributions. Can you only cluster vertical PNSDs and then show the median distributions of the ground-based PNSD for these cluster periods? I ask this as you want to identify connections between the distributions.
3.4 Biomass burning plume advection
Page 29, line 554 - 555:
Comment: Extend the sentence “… observed with the mSEMS at higher altitudes … observed with the SEMS at ground level …”
Page 30, line 562 - 570:
Comment: I do not agree with extensive discussions of details in the main manuscript while figures are found in the supplementary information. Either you include all in the main manuscript or you put the explanation to the supplementary information where the figures are found. Having scientific discussions in the main manuscript that need the detailed reading of the supplementary information are in my view not in the sense of the use of supplementary information, you here simply extend the main manuscript. Decide!
3.5 Source contribution to climate relevant aerosol properties
Page 30, line 584 - 586:
Comment: Please check sense of sentence as you compare here the different categories to the background conditions!
Page 31, line 602 - 607:
Same comment as above: (Repetition) I do not agree with extensive discussions of details in the main manuscript while figures are found in the supplementary information. Either you include all in the main manuscript or you put the explanation to the supplementary information where the figures are found. Having scientific discussions in the main manuscript that need the detailed reading of the supplementary information are in my view not in the sense of the use of supplementary information, you here simply extend the main manuscript. Decide!
4 Conclusions
Page 33, line 632:
Comment: “… with enhanced optical properties …” - Please be more specific here!
Page 33, line 649:
Comment: With view on the values, are you referring to median values? Please state!
Detailed scientific comments (supplementary information):
Figure S2:
Comment: Does the RH show the ambient RH outside or is it the RH after drying. In this case it would be quite high especially for filter-based measurements? Please comment!
Figure S7:
Comment: From the colour coding I cannot see the two PNSDs for both size ranges in each plot. Can you simply only show the mean cluster PNSD for both size ranges in each plot?
Figure S14:
Comment: To make the figure caption complete you need to label also a), b), and c).
Page 30, line 251:
Comment: Please check comment in German language in this line!
Figure S22:
Comment: For my understanding Figure S22 d)e)f) should be the same as Figure 15 a)b)c) in main manuscript. You use different x-scaling, but also look at Figure S22d) which looks different from Figure 15a)?
Specific language comments (main manuscript):
Abstract
Page 1, line 19:
… aerosol number size distribution …
3.1 Campaign overview
Page 16, line 323:
… peaked …
3.2 Background versus fresh pollution regimes
Page 20, line 382:
…. This data …
3.4 Biomass burning plume advection
Page 25, line 480:
…… arrived about 300 m above the ground with a …
Page 28, line 532:
Check language “between” and following of that line!
Page 28, Figure 13:
… clustered PNSD at ground level covering …
Page 29, line 546:
… (blue, vP1_100 c₂) …
Page 30, line 577:
… clustered particle number size distributions …
Specific language comments (supplementary information):
Page 18, line 136:
… Table S6 …
Page 20, line 170:
… is …
Page 32, line 274:
… a first broadened …
Page 32, line 275:
… a second …
Page 32, line 276:
… a third …
Page 32, line 277:
… 39.8 …

Citation: https://doi.org/10.5194/egusphere-2025-5710-RC1
RC2: 'Comment on egusphere-2025-5710', Anonymous Referee #2, 17 Feb 2026

This study presents a very good analysis of aerosol properties measured at different heights in Southern Greenland fjords. By combining ground-based instruments with tethered balloon measurements, the authors provide a very good dataset that shows how aerosols vary up to several hundred meters above the surface. They identify four main source types: local pollution, aged marine background air, biomass burning plumes, and new particle formation events. The results show that both local human activities and long-range transported wildfire smoke can strongly increase CCN concentrations and influence aerosol optical properties. The study highlights how aerosol properties change with altitude and show why vertical measurements are important for understanding aerosol–cloud interactions. The analysis is well supported, and the connection between aerosol sources and climate-relevant properties is convincing. Also, the manuscript is clearly written and well structured. Overall, I recommend the manuscript for publication.

Citation: https://doi.org/10.5194/egusphere-2025-5710-RC2
AC1: 'Author Comment on egusphere-2025-5710', Julia Schmale, 30 Mar 2026

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-5710/egusphere-2025-5710-AC1-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2025-5710-AC1

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload

AR by Julia Schmale on behalf of the Authors (30 Mar 2026) Author's response Author's tracked changes Manuscript

ED: Publish as is (29 Apr 2026) by Tuukka Petäjä

AR by Julia Schmale on behalf of the Authors (09 May 2026) Manuscript

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Short summary

We studied sources, vertical dispersion and properties of aerosols in a Greenlandic fjord system and identified four main types: marine background, local anthropogenic, growth events, biomass burning (BB). Anthropogenic emissions increased absorption coefficients, BB significantly increased the cloud condensation number concentrations, growth events were very similar to background with regards to scattering coefficients. Aerosol properties and origins were distinct throughout the boundary layer.