Potential impact of carbonaceous aerosol on the upper troposphere and lower stratosphere (UTLS) and precipitation during Asian summer monsoon in a global model simulation

Fadnavis, Suvarna; Kalita, Gayatry; Kumar, K. Ravi; Gasparini, Blaž; Li, Jui-Lin Frank

doi:https://doi.org/10.5194/acp-17-11637-2017

Articles | Volume 17, issue 18

https://doi.org/10.5194/acp-17-11637-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/acp-17-11637-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 17, issue 18

Research article

|

28 Sep 2017

Research article |

| 28 Sep 2017

Potential impact of carbonaceous aerosol on the upper troposphere and lower stratosphere (UTLS) and precipitation during Asian summer monsoon in a global model simulation

Suvarna Fadnavis, Gayatry Kalita, K. Ravi Kumar, Blaž Gasparini, and Jui-Lin Frank Li

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Final revised paper (published on 28 Sep 2017)
Supplement to the final revised paper
Preprint (discussion started on 17 Mar 2017)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review of Paper: Potential impact of carbonaceous aerosols on the Upper Troposphere and Lower Stratosphere (UTLS) by Fadnavis et al. 2017, submitted to Atmospheric Chemistry and Physics', Anonymous Referee #1, 03 Apr 2017
- AC1: 'Replies to Anonymous Referee #1', S. Fadnavis, 04 Jul 2017
RC2: 'Review of "Potential impact of carbonaceous aerosols on the Upper Troposphere and Lower Stratosphere (UTLS) during Asian summer monsoon in a global model simulation"', Anonymous Referee #2, 15 May 2017
- AC2: 'Replies to Anonymous Referee #2', S. Fadnavis, 04 Jul 2017

Peer-review completion

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

AR by Suvarna Fadnavis on behalf of the Authors (04 Jul 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (05 Jul 2017) by Rolf Müller

RR by Anonymous Referee #1 (05 Jul 2017)

Suggestions for revision or reasons for rejection

Review of Paper: Potential impact of carbonaceous aerosols on the Upper Troposphere and Lower Stratosphere (UTLS) and precipitation during Asian summer monsoon in a global model simulation by Fadnavis et al. 2017, submitted to Atmospheric Chemistry and Physics

In general the paper is improved. However there are some issues that needed to be addressed before publication, especially Major concern #1.

Major concerns:
1. In the previous paper version, the increased heating rate due to BC/OC near the tropopause in the ASM region was 0.003-0.005 K/day; however in the revised the version, the heating rate is 0.02-0.03 K/day, which is a factor of 6 larger. The heating rate of CTRL run remains the same between two versions of the paper. The BC/OC amount in UTLS remains similar (about 2 ng/m3). I wonder what happened? What have you changed? Also I noticed your TOA radiative forcing changed from strong negative to positive…Please explain.

2. The authors added more model experiments: add “double OC only run” and double “BC only run”. Line 366-369: the radiative forcing for each case do not add up (compared with “double OC and BC run”). I can imagine the system is non-linear, but please provide more discussions on what cause the non-linearity.

3. Line 363-369: I am not convinced by the discussion on the temperature anomaly core in figure 4f. It is good to see in FigureS3a, the temp anomaly core is in the “double BC only run”. I am still wondering which leads to the warming core, note the core in the figure extends to mid-high latitudes. The discussions in the paper are not enough, and seems the authors are somehow guessing. Please justify.

Line 348: ASM region, not ASM

Line 216-217: re-write the sentence. I assume you meant the values range from surface to 10 km in model, while 6 km in observations.

Line 366: Figure 8 instead of Figure 7?

Please clarify the confidence level used for multiple figures. Are they 99% or 95%? In the response, you mentioned 95% while 99% in the figure captions.

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RR by Anonymous Referee #2 (13 Jul 2017)

ED: Reconsider after minor revisions (Editor review) (14 Jul 2017) by Rolf Müller

AR by Suvarna Fadnavis on behalf of the Authors (20 Jul 2017) Author's response Manuscript

ED: Reconsider after minor revisions (Editor review) (01 Aug 2017) by Rolf Müller

AR by Suvarna Fadnavis on behalf of the Authors (09 Aug 2017) Author's response Manuscript

ED: Reconsider after minor revisions (Editor review) (25 Aug 2017) by Rolf Müller

AR by Suvarna Fadnavis on behalf of the Authors (29 Aug 2017) Author's response Manuscript

ED: Publish as is (29 Aug 2017) by Rolf Müller

AR by Suvarna Fadnavis on behalf of the Authors (29 Aug 2017) Manuscript

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Short summary

In this study, the model simulations show that monsoon convection over the Bay of Bengal, the South China Sea and southern flanks of the Himalayas transports Asian carbonaceous aerosol into the UTLS. Carbonaceous aerosol induces enhancement in heating rate, vertical velocity and water vapor transport in the UTLS. Doubling of carbonaceous aerosols creates an anomalous warming over the TP. It generates monsoon Hadley circulation and thus increases precipitation over India and northeast China.