Wildfire smoke, Arctic haze, and aerosol effects on mixed-phase and cirrus clouds over the North Pole region during MOSAiC: an introduction

Engelmann, Ronny; Ansmann, Albert; Ohneiser, Kevin; Griesche, Hannes; Radenz, Martin; Hofer, Julian; Althausen, Dietrich; Dahlke, Sandro; Maturilli, Marion; Veselovskii, Igor; Jimenez, Cristofer; Wiesen, Robert; Baars, Holger; Bühl, Johannes; Gebauer, Henriette; Haarig, Moritz; Seifert, Patric; Wandinger, Ulla; Macke, Andreas

doi:https://doi.org/10.5194/acp-21-13397-2021

Articles | Volume 21, issue 17

https://doi.org/10.5194/acp-21-13397-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-21-13397-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 21, issue 17

Research article

| Highlight paper

|

09 Sep 2021

Research article | Highlight paper |

| 09 Sep 2021

Wildfire smoke, Arctic haze, and aerosol effects on mixed-phase and cirrus clouds over the North Pole region during MOSAiC: an introduction

Ronny Engelmann, Albert Ansmann, Kevin Ohneiser, Hannes Griesche, Martin Radenz, Julian Hofer, Dietrich Althausen, Sandro Dahlke, Marion Maturilli, Igor Veselovskii, Cristofer Jimenez, Robert Wiesen, Holger Baars, Johannes Bühl, Henriette Gebauer, Moritz Haarig, Patric Seifert, Ulla Wandinger, and Andreas Macke

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Final revised paper (published on 09 Sep 2021)
Preprint (discussion started on 29 Dec 2020)

Interactive discussion

Status: closed

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

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SC1: 'Comment on acp-2020-1271', Jayanta Kar, 24 Feb 2021
RC1: 'Review', Anonymous Referee #1, 11 Mar 2021
RC2: 'Review of acp-2020-1271', Anonymous Referee #2, 28 Mar 2021
AC1: 'Reply to the comment of Jayanta Kar', Albert Ansmann, 17 Jun 2021
AC2: 'Reply to comments of referee #1', Albert Ansmann, 17 Jun 2021
AC3: 'Reply to comments of referee #2', Albert Ansmann, 17 Jun 2021

Peer-review completion

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

AR by Albert Ansmann on behalf of the Authors (17 Jun 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (24 Jun 2021) by Geraint Vaughan

RR by Anonymous Referee #1 (10 Jul 2021)

Suggestions for revision or reasons for rejection

The authors did a very good job responding to my comments and answering my questions. I like the new Table 1.

Fig. 14: As a very minor recommendation for the authors to consider if they wish: they could mention that the paper’s INP concentrations of 0.1 to 0.5 L-1 are in line with previous Arctic in situ observations at similar temperatures of -28.5 oC, especially given their uncertainty ranges in Table 1. The observations that I am aware of range from 0.001 to ~2.5 L-1 between -25 and -28.5 oC (Creamean et al., 2019; Hartmann et al., 2020; Mason et al., 2016; Wex et al., 2019).

Technical comments:
P6L23: I am not sure a manuscript in preparation should be cited here?
P3L31: “to what extent”
P5L15: “above the ground” (or maybe more accurately, above the surface?)
P14L27: “The goal was to …”

References:

Creamean, J. M., Cross, J. N., Pickart, R., McRaven, L., Lin, P., Pacini, A., Hanlon, R., Schmale, D. G., Ceniceros, J., Aydell, T., Colombi, N., Bolger, E., and DeMott, P. J.: Ice Nucleating Particles Carried From Below a Phytoplankton Bloom to the Arctic Atmosphere, 46, 8572–8581, https://doi.org/10.1029/2019GL083039, 2019.

Hartmann, M., Adachi, K., Eppers, O., Haas, C., Herber, A., Holzinger, R., Hünerbein, A., Jäkel, E., Jentzsch, C., Pinxteren, M. van, Wex, H., Willmes, S., and Stratmann, F.: Wintertime Airborne Measurements of Ice Nucleating Particles in the High Arctic: A Hint to a Marine, Biogenic Source for Ice Nucleating Particles, 47, e2020GL087770, https://doi.org/10.1029/2020GL087770, 2020.

Mason, R. H., Si, M., Chou, C., Irish, V. E., Dickie, R., Elizondo, P., Wong, R., Brintnell, M., Elsasser, M., Lassar, W. M., Pierce, K. M., Leaitch, W. R., MacDonald, A. M., Platt, A., Toom-Sauntry, D., Sarda-Estève, R., Schiller, C. L., Suski, K. J., Hill, T. C. J., Abbatt, J. P. D., Huffman, J. A., DeMott, P. J., and Bertram, A. K.: Size-resolved measurements of ice-nucleating particles at six locations in North America and one in Europe, 16, 1637–1651, https://doi.org/10.5194/acp-16-1637-2016, 2016.

Wex, H., Huang, L., Zhang, W., Hung, H., Traversi, R., Becagli, S., Sheesley, R. J., Moffett, C. E., Barrett, T. E., Bossi, R., Skov, H., Hünerbein, A., Lubitz, J., Löffler, M., Linke, O., Hartmann, M., Herenz, P., and Stratmann, F.: Annual variability of ice-nucleating particle concentrations at different Arctic locations, 19, 5293–5311, https://doi.org/10.5194/acp-19-5293-2019, 2019.

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RR by Anonymous Referee #2 (23 Jul 2021)

Suggestions for revision or reasons for rejection

The authors did a great effort to improve the manuscript, and included several new parts and methods. The manuscript has changed a lot. Please find below few remaining minor comments to the new additions of the manuscript. It would be optimum for the readers if the authors can revise the text based on these comments.

Nomenclature of variables in the figures: I suggest using the same nomenclature in the figures for the extinction coefficient variable throughout the paper. Specifically, Figure 4,10,13 have “Extinction cf” while Figure 15,17,18 “σ”.

Lidar ratio symbol (page 9, line 34): Is there a reason why for the extinction-to-backscatter ratio the symbol L is chosen in this paper, instead of the symbol S or the abbreviation LR which are used in the literature? Consider to revise or include a small comment on the paper for this selection.

Page 18, line 31: “ Lifting phases of gravity waves can be as long as 20 minutes (1200 s) as our Doppler lidar and radar observations conducted in several field campaigns during the last 10 years indicate”. If available, consider including some references for this.

Concerning the uncertainties introduced and discussed: As the uncertainties are different for different mixing states, the authors should consider adding in Table 1 a comment with the information on the mixing state these uncertainties are representative of. See specific description of the inconsistencies below.

Page 7, line 31: In the referenced paper of Haaring et al. 2019, Table 1, the uncertainty of the n_50 is a Factor of 2 and for n_250 is 30%, while in the Table 1 of this work the uncertainty provided for n_50 is 50%, and for n_250 is <=25%. Additionally, from the POLIPHON method one can easily calculate that the type-separated extinction coefficient uncertainties, on a layer where mixtures of different aerosol types prevail, can exceed 30% for the non-dominant aerosol particles. For example, for an aerosol layer with particle depolarization ratio of 10±1% (dust mixtures), using the POLIPHON method with δ_dust = 30±3% και δ_nondust = 5±2% the weight calculated is 0.236±0.052%. For a layer with βp_total=1±0.1Mm^(-1)sr^(-1) (uncertainty defined in this work), the pure dust backscatter uncertainty is propagated as: βp_dust= 0.236±0.057 Mm^(-1)sr^(-1) and for the non dust: βp_nondust= 0.764±0.092 Mm^(-1)sr^(-1). With LR_dust = 45±11 Sr, LR_smoke = 85±21 Sr (<25% uncertainty as defined in this paper): ap_dust= 10.6±3.6 Mm^(-1) => 34% error on the dust extinction coefficient, and ap_smoke = 64.9±17.9 Mm^(-1) => 28% error on the smoke extinction coefficient. POLIPHON calculation from this point for the dust mass concentration gives: M_d = 17.7±6.3 => 36% uncertainty. This is an example of a case where the uncertainties provided in Table 1 are lower than the error propagated uncertainties from the measurements and method. That is why a comment on Table 1 on the mixing state representative for these uncertainties would be very useful for the reader.

The effect of the mixing state on the retrievals is partially mentioned in page 7, line 35 for the CCNC retrievals: “Comparisons with airborne in situ measurements showed that CCNC can be obtained with an uncertainty of about 30% (inversion of multiwavelength data) to 50% (conversion of the 532 nm extinction coefficient) when the aerosol type (and thus the typical aerosol size distribution) is known, and about a factor of 2 if the aerosol type is not well known or mixtures of different aerosol types prevail..”. But not for the rest retrievals (page 7 line 28): “Regarding the aerosol microphysical properties, the comparisons showed that particle number concentrations, surface area, volume and mass concentrations can be obtained with an uncertainty of 25-50% (see Table 1) ..”.

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ED: Publish subject to minor revisions (review by editor) (29 Jul 2021) by Geraint Vaughan

AR by Albert Ansmann on behalf of the Authors (02 Aug 2021) Author's response Author's tracked changes Manuscript

ED: Publish as is (04 Aug 2021) by Geraint Vaughan

Post-review adjustments

AA: Author's adjustment | EA: Editor approval

AA by Albert Ansmann on behalf of the Authors (02 Sep 2021) Author's adjustment Manuscript

EA: Adjustments approved (02 Sep 2021) by Geraint Vaughan

Short summary

A Raman lidar was operated aboard the icebreaker Polarstern during MOSAiC and monitored aerosol and cloud layers in the central Arctic up to 30 km height. The article provides an overview of the spectrum of aerosol profiling observations and shows aerosol–cloud interaction studies for liquid-water and ice clouds. A highlight was the detection of a 10 km deep wildfire smoke layer over the North Pole up to 17 km height from the fire season of 2019, which persisted over the whole winter period.