Lower-stratospheric aerosol measurements in eastward-shedding vortices over Japan from the Asian summer monsoon anticyclone during the summer of 2018

Fujiwara, Masatomo; Sakai, Tetsu; Nagai, Tomohiro; Shiraishi, Koichi; Inai, Yoichi; Khaykin, Sergey; Xi, Haosen; Shibata, Takashi; Shiotani, Masato; Pan, Laura L.

doi:https://doi.org/10.5194/acp-21-3073-2021

Articles | Volume 21, issue 4

https://doi.org/10.5194/acp-21-3073-2021

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

https://doi.org/10.5194/acp-21-3073-2021

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

Articles | Volume 21, issue 4

Research article

|

01 Mar 2021

Research article |

| 01 Mar 2021

Lower-stratospheric aerosol measurements in eastward-shedding vortices over Japan from the Asian summer monsoon anticyclone during the summer of 2018

Masatomo Fujiwara, Tetsu Sakai, Tomohiro Nagai, Koichi Shiraishi, Yoichi Inai, Sergey Khaykin, Haosen Xi, Takashi Shibata, Masato Shiotani, and Laura L. Pan

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Final revised paper (published on 01 Mar 2021)
Preprint (discussion started on 21 Oct 2020)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review', Anonymous Referee #1, 16 Nov 2020
- AC1: 'Response', Masatomo Fujiwara, 16 Dec 2020
RC2: 'Review of “Lower-stratospheric aerosol measurements in eastward shedding vortices over Japan from the Asian summer monsoon anticyclone during the summer of 2018” by Fujiwara et al.', Michelle Santee, 16 Nov 2020
- AC2: 'Response', Masatomo Fujiwara, 16 Dec 2020
RC3: 'Reviewer Comment', Anonymous Referee #3, 19 Nov 2020
- AC3: 'Response', Masatomo Fujiwara, 16 Dec 2020

Peer-review completion

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

AR by Masatomo Fujiwara on behalf of the Authors (28 Dec 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (31 Dec 2020) by Rolf Müller

RR by Anonymous Referee #1 (04 Jan 2021)

RR by Anonymous Referee #3 (08 Jan 2021)

Suggestions for revision or reasons for rejection

The manuscript 'Lower-stratospheric aerosol measurements in eastward shedding vortices over Japan from the Asian summer monsoon anticyclone during the summer of 2018' by Fujiwara et al., is ready for publication after revising the following comments:

1) P2/L51: ’The enhanced aerosol particle signature in the ASM anticyclone at 14–18 km altitude is known as the Asian Tropopause Aerosol Layer (ATAL), which is believed to consist of carbonaceous and sulphate materials, mineral dust, and nitrate particles (Vernier et al., 2015, 2018; Brunamonti et al., 2018; Bossolasco et al., 2020; Hanumanthu et al., 2020).'

I still recommend to revise this sentence to better make clear which information is from measurements and which from model simulations (e.g. as follows):

The enhanced aerosol particle signature in the ASM anticyclone at 14–18 km altitude found in satellite as well as in in situ balloon-borne measurements is known as the Asian Tropopause Aerosol Layer (ATAL) (e.g. Vernier et al., 2015, 2018; Brunamonti et al., 2018; Hanumanthu et al., 2020). Based on model simulations ATAL is believed to consist of carbonaceous and sulphate materials,
mineral dust, and nitrate particles (e.g. Fadnavis et al., 2013; Gu et al.,2016; Lau et al., 2018; Fairlie et al., 2020; Bossolasco et al., 2020;...). However, only limited information on the chemical composition of the ATAL particles is available from measurements (e.g. Martinsson et al., 2014; Vernier et al., 2018; Höpfner et al., 2019;....).

I just mentioned a few references. Feel free to add some other references or select some other references. I propose to better check the current status of publications to the issue of chemical composition of ATAL.

Fadnavis, S., Semeniuk, K., Pozzoli, L., Schultz, M. G., Ghude, S. D., Das, S., and Kakatkar, R.: Transport of aerosols into the UTLS and their impact on the Asian monsoon region as seen in a global model simulation, Atmos. Chem. Phys., 13, 8771–8786, https://doi.org/10.5194/acp-13-8771-2013, 2013.

Martinsson, B. G., Friberg, J., Andersson, S. M., Weigelt, A., Hermann, M., Assmann, D., Voigtländer, J., Brenninkmeijer, C. A. M., van Velthoven, P. J. F., and Zahn, A.: Comparison between CARIBIC Aerosol Samples Analysed by Accelerator-
Based Methods and Optical Particle Counter Measurements, Atmos. Meas. Tech., 7, 2581–2596,
https://doi.org/10.5194/amt-7-2581-2014, 2014.

Gu, Y., Liao, H., and Bian, J.: Summertime nitrate aerosol in the upper troposphere and lower stratosphere over the Tibetan Plateau and the South Asian summer monsoon region, Atmos. Chem. Phys., 16, 6641–6663, https://doi.org/10.5194/acp-16-6641-2016, 2016.

Lau, W. K. M., Yuan, C., and Li, Z.: Origin, Maintenance and Variability of the Asian Tropopause Aerosol Layer (ATAL): The Roles of Monsoon Dynamics, Sci. Rep., 8, 3960,
https://doi.org/10.1038/s41598-018-22267-z, 2018.

Fairlie, T. D., Liu, H., Vernier, J.-P., Campuzano-Jost, P., Jimenez, J. L., Jo, D. S., Zhang, B., Natarajan, M., Avery, M. A., and Huey, G.: Estimates of Regional Source Contributions to the Asian Tropopause Aerosol Layer Using a Chemical Transport Model, J. Geophys. Res., 125, e2019JD031506,
https://doi.org/10.1029/2019JD031506, 2020.

2) P22/L400:

'However, it should be noted that the lidar BSR and PDR measurements cannot exclude the possibility of co-existence of other types of solid aerosol particles such as mineral dust, black carbon, and some types of carbonaceous aerosols which are solid.'

Please add here some references for publications that propose that ATAL could consist of solid aerosol particles such as mineral dust, black carbon, and some types of carbonaceous aerosols which are solid. It would be an added value for the paper to know if these references are based on simulations or measurements of ATAL.

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RR by Michelle Santee (13 Jan 2021)

Suggestions for revision or reasons for rejection

The authors have done a good job in revising the manuscript in response to the comments of the three referees. In my opinion the reviewers’ concerns have for the most part been adequately addressed. I have only a few remaining suggestions (mostly minor wording changes where edits or additions were made during revision) that I feel should be considered before publication.

• L108-109: Assuming that I am interpreting this sentence correctly, then I think that both instances of “with” in “… uncertainty of the normalization value of BSR with … and that of the extinction-to-backscatter ratio with …” should be “to be”. In addition, “uncertainty of BSR were then estimated” should be “uncertainty of BSR was then estimated”.

• L140-144: I think it would be good to add “(not shown)” somewhere in this sentence (perhaps right after “quick comparison”).

• L146-148: Since the papers by Popovic & Plumb [2001] and Santee et al. [2017] are already referenced in this manuscript, it would be appropriate to note here that those studies also employed MSF.

• L151: this isentropic surface will be focused in Section 3.2 --> the isentropic surface we will focus on in Section 3.2

• L158: We found that CAMS --> We found (not shown) that CAMS

• L181: prevent from characterizing the --> prevent characterization of the

• L182-183: highly variable around this date and was located at 17 km on that date --> highly variable at the time and was located at 17 km on that date

• L196: for Tsukuba data we do not plot the data --> for Tsukuba we do not plot the data

• L287: 20-25 August event--> 20-24 August event

• L325-326: My apologies for not commenting on this point in the original manuscript, but it would be appropriate to add two recent publications on the Australian New Year’s pyroCbs to the list of papers showing that extensive wildfires influence stratospheric aerosol loading: Kablick et al. [GRL, 2020; https://doi.org/10.1029/2020GL088101] and Khaykin et al. [Communications Earth & Environment, 2020; https://doi.org/10.1038/s43247-020-00022-5].

• L393: showed the PDR values --> showed PDR values

• L443-445: An author was added in revision, but the author contributions section has not been updated accordingly.

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ED: Publish subject to minor revisions (review by editor) (17 Jan 2021) by Rolf Müller

AR by Masatomo Fujiwara on behalf of the Authors (21 Jan 2021) Author's response Author's tracked changes Manuscript

ED: Publish as is (26 Jan 2021) by Rolf Müller

Short summary

Lidar aerosol particle measurements in Japan during the summer of 2018 were found to detect the eastward extension of the Asian tropopause aerosol layer from the Asian summer monsoon anticyclone in the lower stratosphere. Analysis of various other data indicates that the observed enhanced particle levels are due to eastward-shedding vortices from the anticyclone, originating from pollutants emitted in Asian countries and transported vertically by convection in the Asian summer monsoon region.