the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 09 Apr 2024
Ice-nucleating particles active below -24 °C in a Finnish boreal forest and their relationship to bioaerosols
Abstract. Cloud properties are strongly influenced by ice formation, hence we need to understand the sources of ice-nucleating particles (INPs) around the globe. Boreal forests are known as sources of bioaerosol and recent work indicates that these dominate the INP spectra above -24 °C. To quantify the INP population at temperatures below -24 °C, we deployed a portable cloud expansion chamber (PINE) in a Finnish boreal forest from March 13, 2018 to May 11, 2018. Using the 6 min time resolution PINE data, we present several lines of evidence that INPs below -24 °C in this location are also from biological sources: an INP parameterization developed for a pine forest site in Colorado, where many INPs were shown to be biological, produced a good fit to our measurements; a moderate correlation of INP with aerosol concentration larger than 0.5 μm and the fluorescent bioaerosol concentration; a negative correlation with relative humidity that may relate to enhanced release of bioaerosol at low humidity from local sources such as the prolific lichen population in boreal forests. The absence of correlation with ultrafine particles (3.5 to 50 nm) indicates that new particle formation events are not sources of INP. This study should motivate further work to establish if the commonality in bioaerosol ice nucleating properties between spring in Finland and summer in Colorado is more generally applicable to different coniferous forest locations and times, and also to determine to what extent these bioaerosols are transported to locations where they may affect clouds.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Atmospheric Chemistry and Physics. The peer-review process was guided by an independent editor, and the authors also have no other competing interests to declare.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.-
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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.
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Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2024-853', Anonymous Referee #1, 08 May 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-853/egusphere-2024-853-RC1-supplement.pdf
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AC1: 'Reply on RC1', Franziska Vogel, 09 Jul 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-853/egusphere-2024-853-AC1-supplement.pdf
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AC1: 'Reply on RC1', Franziska Vogel, 09 Jul 2024
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RC2: 'Comment on egusphere-2024-853', Anonymous Referee #2, 13 May 2024
Publisher's note: the content of this comment was adjusted on 21 May 2024 after approval of the ACP executive editors since some formulations were inappropriate.
General Comments:
This work reports on the measurements of ice-nucleating particles (INPs) active below -24 degree C in a Finnish boreal forest during the HyICE-2018 campaign (13 March to 11 May 2018). In my impression, the advance of this work is to show the time series of the INP number concentrations measured using a PINE chamber over this campaign period. On the other hand, it seems that the key research approaches and conclusions of this study are very similar to those of earlier studies at the same site and period. For example, Brasseur et al. (2022) already reported the comparison of INPs active at temperatures around -30 degree C measured using several cloud-chamber-type instruments (PINE, SPIN, and PINC) with those active above -25 degree C measured using cold-stage-type instruments (INSEKT and uL-NIPI) during the same campaign, while this study has added some data points derived from the PINE. In addition, Brasseur et al. (2022) already evaluated the performance of INP parameterizations designed by DeMott et al. (2010), Tobo et al. (2013), and Schneider et al. (2021), and concluded that the Tobo et al. (2013) parameterization could better reproduce the number concentrations of INPs active below -24 degree C (-29 to -32 degree C) during this campaign. Schneider et al. (2021) also reported the comparison of the INP schemes designed by DeMott et al. (2010) and Tobo et al. (2013) with the INP data at the same site. This work contains some new results and discussion (e.g., INPs vs. RH and new particle formation (NPF)), but the results are based on the correlation coefficients listed in a table-like figure (Figure 6) only. For these reasons, I don’t think that the current manuscript measures up to ACP’s standards.
Specific Comments:
1) The time series of INP data measured using the PINE chamber are unique and potentially valuable. However, this work appears to repeat essentially the same work as reported by Schneider et al. (2021) and Brasseur et al. (2022). I strongly encourage that the authors reconsider if they can add new topics and findings using their data sets. Then, the authors should significantly update the contents of the manuscript in order to clarify the difference between this study and other earlier studies.
2) In my understanding, cloud-chamber-type instruments other than PINE (e.g., SPIN, PINC) had also been used to measure the time series of INPs active below -24 degree C at this site during the HyICE-2018 campaign. The authors should compare the difference between the PINE and the other instruments in the lower temperature regime and evaluate the strengths (and limitations) of the PINE. For example, to my knowledge, Paramonov et al. (2020) already reported the full INP data sets active around -30 degree C measured using a PINC during the overlapping period.
3) Please explain more details for the WIBS data. It is unclear how the WIBS fluorescent particle data were applied to the Tobo et al. (2013) (2) parameterization. As a result, it is difficult to judge whether the authors’ explanations that “this means that the measured INP concentration ~ from different sources (Lines 250-252)” and “a second parameterization proposed by Tobo et al. (2013), linking ~ but they are not identical (Lines 373-376)” are indeed reasonable. For example, Tobo et al. (2013) used the data on fluorescent particles larger than 0.5 um measured using UV-APS that employes an excitation wavelength of 355 nm and detects laser-induced fluorescence spectra in the range of 420–575 nm). Did they use the same setup as the UV-APS?
4) Brasseur et al. (2022) announced that “forthcoming studies would explore atmospheric vertical profiles of INPs, INP sources and transport modeling, plausible links between INP abundance and NPF, and the ice nucleation activity of boreal biology such as flora and fungi”. If this work is a part of the forthcoming studies, the authors should present some more details for the comparison of INPs with NPF. Since the information on the correlation coefficients only (Figure 6) is obviously insufficient, the authors should show the time series of the INP and NPF data.
5) The possible links between INPs and low RH are potentially interesting. On the other hand, many earlier studies have reported elevated INP concentrations under high RH conditions at a forested site in Colorado (Huffmann et al., 2013; Prenni et al., 2013; Tobo et al., 2013) and other locations (Wright et al., 2014). I would suggest showing figure(s) that could explain the relationship between INP and RH data. Then, please discuss the discrepancy between this study and the above studies if there was indeed a clear negative correlation between the INP and RH data.
Technical Comments:
6) I would suggest changing the title appropriately, because other related literatures (Paramonov et al. 2020; Brasseur et al., 2023) have already reported INP data below -24 degree C during the HyICE-2014.
7) Please indicate the full name and the abbreviated name in the same manner (e.g., see “Portable Ice Nucealtion Experiment (PINE)” in Line 59 and “PINC (Portable Ice Nucleation Chamber)” in Line 104.
8) Please explain some more details for the experimental setup for the PINE. For example, what is the cut-off diameter of the inlet?
9) I assume that the PINE uses an OPC that can detect larger aerosol particles, liquid cloud droplets and ice crystals as single particles (Line 84), but the size range covered by this OPC is not clear. It is also unclear how the PINE used here discriminated ice crystal signals from ambient aerosol particles and liquid droplets?
10) Lines 96-97: Please explain if the INP number concentrations presented here were corrected to the values at standard temperature and humidity conditions (0 degree C and 1 atom) or not.
11) Line 99: What do you mean by “the uncertainty for PINE is given as 20 %”?
12) Lines 111-115: Please specify the RH setup for mixed-phase cloud conditions in the PINE chamber.
13) Figure 2a: I would suggest including INP data derived from SPIN and PINC during the HyICE-2014 campaign.
14) Lines 262-264: Please explain how the PINE chamber captures deposition and condensation nucleation in the Methods section.
15) Lines 271-272: Please revise this description if the temperatures were between -27 and -30 degree C as explained in the Figure 6 caption.
16) Line 284: What do you mean by “FP3 channel”? Please also check my comment 3.
References:
Brasseur et al. (2023), https://doi.org/10.5194/acp-22-5117-2022
DeMott et al. (2010), https://doi.org/10.1073/pnas.0910818107
Huffman et al. (2013), https://doi.org/10.5194/acp-13-6151-2013
Paramonov et al. (2020), https://doi.org/10.5194/acp-20-6687-2020
Prenni et al. (2013), https://doi.org/10.1029/2012GL053953
Schneider et al. (2021), https://doi.org/10.5194/acp-21-3899-2021
Tobo et al. (2013), https://doi.org/10.1002/jgrd.50801
Wright et al. (2014), https://doi.org/10.1080/02786826.2014.968244Citation: https://doi.org/10.5194/egusphere-2024-853-RC2 -
AC2: 'Reply on RC2', Franziska Vogel, 09 Jul 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-853/egusphere-2024-853-AC2-supplement.pdf
-
AC2: 'Reply on RC2', Franziska Vogel, 09 Jul 2024
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2024-853', Anonymous Referee #1, 08 May 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-853/egusphere-2024-853-RC1-supplement.pdf
-
AC1: 'Reply on RC1', Franziska Vogel, 09 Jul 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-853/egusphere-2024-853-AC1-supplement.pdf
-
AC1: 'Reply on RC1', Franziska Vogel, 09 Jul 2024
-
RC2: 'Comment on egusphere-2024-853', Anonymous Referee #2, 13 May 2024
Publisher's note: the content of this comment was adjusted on 21 May 2024 after approval of the ACP executive editors since some formulations were inappropriate.
General Comments:
This work reports on the measurements of ice-nucleating particles (INPs) active below -24 degree C in a Finnish boreal forest during the HyICE-2018 campaign (13 March to 11 May 2018). In my impression, the advance of this work is to show the time series of the INP number concentrations measured using a PINE chamber over this campaign period. On the other hand, it seems that the key research approaches and conclusions of this study are very similar to those of earlier studies at the same site and period. For example, Brasseur et al. (2022) already reported the comparison of INPs active at temperatures around -30 degree C measured using several cloud-chamber-type instruments (PINE, SPIN, and PINC) with those active above -25 degree C measured using cold-stage-type instruments (INSEKT and uL-NIPI) during the same campaign, while this study has added some data points derived from the PINE. In addition, Brasseur et al. (2022) already evaluated the performance of INP parameterizations designed by DeMott et al. (2010), Tobo et al. (2013), and Schneider et al. (2021), and concluded that the Tobo et al. (2013) parameterization could better reproduce the number concentrations of INPs active below -24 degree C (-29 to -32 degree C) during this campaign. Schneider et al. (2021) also reported the comparison of the INP schemes designed by DeMott et al. (2010) and Tobo et al. (2013) with the INP data at the same site. This work contains some new results and discussion (e.g., INPs vs. RH and new particle formation (NPF)), but the results are based on the correlation coefficients listed in a table-like figure (Figure 6) only. For these reasons, I don’t think that the current manuscript measures up to ACP’s standards.
Specific Comments:
1) The time series of INP data measured using the PINE chamber are unique and potentially valuable. However, this work appears to repeat essentially the same work as reported by Schneider et al. (2021) and Brasseur et al. (2022). I strongly encourage that the authors reconsider if they can add new topics and findings using their data sets. Then, the authors should significantly update the contents of the manuscript in order to clarify the difference between this study and other earlier studies.
2) In my understanding, cloud-chamber-type instruments other than PINE (e.g., SPIN, PINC) had also been used to measure the time series of INPs active below -24 degree C at this site during the HyICE-2018 campaign. The authors should compare the difference between the PINE and the other instruments in the lower temperature regime and evaluate the strengths (and limitations) of the PINE. For example, to my knowledge, Paramonov et al. (2020) already reported the full INP data sets active around -30 degree C measured using a PINC during the overlapping period.
3) Please explain more details for the WIBS data. It is unclear how the WIBS fluorescent particle data were applied to the Tobo et al. (2013) (2) parameterization. As a result, it is difficult to judge whether the authors’ explanations that “this means that the measured INP concentration ~ from different sources (Lines 250-252)” and “a second parameterization proposed by Tobo et al. (2013), linking ~ but they are not identical (Lines 373-376)” are indeed reasonable. For example, Tobo et al. (2013) used the data on fluorescent particles larger than 0.5 um measured using UV-APS that employes an excitation wavelength of 355 nm and detects laser-induced fluorescence spectra in the range of 420–575 nm). Did they use the same setup as the UV-APS?
4) Brasseur et al. (2022) announced that “forthcoming studies would explore atmospheric vertical profiles of INPs, INP sources and transport modeling, plausible links between INP abundance and NPF, and the ice nucleation activity of boreal biology such as flora and fungi”. If this work is a part of the forthcoming studies, the authors should present some more details for the comparison of INPs with NPF. Since the information on the correlation coefficients only (Figure 6) is obviously insufficient, the authors should show the time series of the INP and NPF data.
5) The possible links between INPs and low RH are potentially interesting. On the other hand, many earlier studies have reported elevated INP concentrations under high RH conditions at a forested site in Colorado (Huffmann et al., 2013; Prenni et al., 2013; Tobo et al., 2013) and other locations (Wright et al., 2014). I would suggest showing figure(s) that could explain the relationship between INP and RH data. Then, please discuss the discrepancy between this study and the above studies if there was indeed a clear negative correlation between the INP and RH data.
Technical Comments:
6) I would suggest changing the title appropriately, because other related literatures (Paramonov et al. 2020; Brasseur et al., 2023) have already reported INP data below -24 degree C during the HyICE-2014.
7) Please indicate the full name and the abbreviated name in the same manner (e.g., see “Portable Ice Nucealtion Experiment (PINE)” in Line 59 and “PINC (Portable Ice Nucleation Chamber)” in Line 104.
8) Please explain some more details for the experimental setup for the PINE. For example, what is the cut-off diameter of the inlet?
9) I assume that the PINE uses an OPC that can detect larger aerosol particles, liquid cloud droplets and ice crystals as single particles (Line 84), but the size range covered by this OPC is not clear. It is also unclear how the PINE used here discriminated ice crystal signals from ambient aerosol particles and liquid droplets?
10) Lines 96-97: Please explain if the INP number concentrations presented here were corrected to the values at standard temperature and humidity conditions (0 degree C and 1 atom) or not.
11) Line 99: What do you mean by “the uncertainty for PINE is given as 20 %”?
12) Lines 111-115: Please specify the RH setup for mixed-phase cloud conditions in the PINE chamber.
13) Figure 2a: I would suggest including INP data derived from SPIN and PINC during the HyICE-2014 campaign.
14) Lines 262-264: Please explain how the PINE chamber captures deposition and condensation nucleation in the Methods section.
15) Lines 271-272: Please revise this description if the temperatures were between -27 and -30 degree C as explained in the Figure 6 caption.
16) Line 284: What do you mean by “FP3 channel”? Please also check my comment 3.
References:
Brasseur et al. (2023), https://doi.org/10.5194/acp-22-5117-2022
DeMott et al. (2010), https://doi.org/10.1073/pnas.0910818107
Huffman et al. (2013), https://doi.org/10.5194/acp-13-6151-2013
Paramonov et al. (2020), https://doi.org/10.5194/acp-20-6687-2020
Prenni et al. (2013), https://doi.org/10.1029/2012GL053953
Schneider et al. (2021), https://doi.org/10.5194/acp-21-3899-2021
Tobo et al. (2013), https://doi.org/10.1002/jgrd.50801
Wright et al. (2014), https://doi.org/10.1080/02786826.2014.968244Citation: https://doi.org/10.5194/egusphere-2024-853-RC2 -
AC2: 'Reply on RC2', Franziska Vogel, 09 Jul 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-853/egusphere-2024-853-AC2-supplement.pdf
-
AC2: 'Reply on RC2', Franziska Vogel, 09 Jul 2024
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Cited
1 citations as recorded by crossref.
Michael P. Adams
Larissa Lacher
Polly Foster
Grace C. E. Porter
Barbara Bertozzi
Kristina Höhler
Julia Schneider
Tobias Schorr
Nsikanabasi S. Umo
Jens Nadolny
Zoé Brasseur
Paavo Heikkilä
Erik S. Thomson
Nicole Büttner
Martin I. Daily
Romy Fösig
Alexander D. Harrison
Jorma Keskinen
Ulrike Proske
Jonathan Duplissy
Markku Kulmala
Tuukka Petäjä
Ottmar Möhler
Benjamin J. Murray
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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