Aerosol direct radiative effect over clouds from a synergy of Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS) reflectances

de Graaf, Martin; Tilstra, L. Gijsbert; Stammes, Piet

doi:https://doi.org/10.5194/amt-12-5119-2019

Articles | Volume 12, issue 9

https://doi.org/10.5194/amt-12-5119-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

New observations and related modelling studies of the aerosol–cloud–climate...

https://doi.org/10.5194/amt-12-5119-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 12, issue 9

Research article

|

25 Sep 2019

Research article |

| 25 Sep 2019

Aerosol direct radiative effect over clouds from a synergy of Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS) reflectances

Martin de Graaf, L. Gijsbert Tilstra, and Piet Stammes

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Final revised paper (published on 25 Sep 2019)
Preprint (discussion started on 08 Mar 2019)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review of OMI/MODIS aerosol-cloud DRE paper', Anonymous Referee #2, 14 Mar 2019
- AC1: 'Reply to anonymous reviewer #2', Martin de Graaf, 28 Jun 2019
RC2: 'Major concerns and questions', Zhibo Zhang, 19 Apr 2019
- AC1: 'Reply to anonymous reviewer #2', Martin de Graaf, 28 Jun 2019
EC1: 'Additional comments on amt-2019-53', Hiren Jethva, 06 May 2019
- AC2: 'Reply to review', Martin de Graaf, 28 Jun 2019

Peer-review completion

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

AR by Martin de Graaf on behalf of the Authors (28 Jun 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (06 Jul 2019) by Hiren Jethva

RR by Anonymous Referee #2 (09 Jul 2019)

Suggestions for revision or reasons for rejection

I reviewed a previous version of this manuscript. My main issues with the previous version were (1) discussion of the anisotropy factor B and related uncertainty; (2) choice of a threshold UVAI=0 as a baseline for the uncertainty calculations; and (3) the fairly simplistic nature of the 2016/2017 data analysis (mentioning ORACLES but not using the data). In this revision the authors have expanded the discussion of (1) and (2), which I appreciate, and added MODIS and OMI above-cloud satellite time series for (3) while noting that the comparison with ORACLES data is better suited for a separate paper (which I hope they do). This makes it more convincing, in my view, than the previous submission.

As a result I do not have technical objections to the publication of this manuscript, although the other reviewer (Z. Zhang) is more of an expert in the forcing aspect than I am, so I would defer to their judgment.

I have a few minor comments, but otherwise find the manuscript acceptable for publication after technical corrections. I would be happy to review these corrections if the Editor feels it would be helpful, although I do not think it is necessary, provided the other reviewer is satisfied.

Previous comment on POLDER: the authors had cited a paper in preparation which compared the OMI/MODIS results against POLDER. I’d suggested the authors provide the results here or remove the reference, since we can’t see the results otherwise (given it’s a paper which has not been submitted yet). They replied that they have added the information and also removed the citation. It’s not clear to me where the information about this comparison has been added, as it doesn’t seem to be in the original section; there is a brief mention in section 4.2 of POLDER but that seems to be it? Mentioning just in case something was inadvertently omitted, but I think it is ok as-is.

Page 7 line 27: a reference for the MODIS sensor should be added (one is already provided for the other satellite instruments used). I don’t have a particular strong feeling about which, but Salmonson et al (1989) is often used: https://ieeexplore.ieee.org/document/20292

Page 10 line 2: Acronym FRESCO needs to be defined at first use.

Page 21 line 4: Acronym AERONET needs to be defined at first use. Also, state which version you are using and provide a reference. It should be the current version 3, with citation Giles et al (2019): https://www.atmos-meas-tech.net/12/169/2019/amt-12-169-2019-discussion.html Also define the data level being used. I see this is level 1.5 rather than the standard level 2; after checking the AERONET website I see level 2 is not available yet for Ascension Island in 2017. It is worth mentioning the difference between levels and stating why level 1.5 is used here.

Page 22 lines 30-32: VIIRS and OMPS acronyms should be defined at first use. Also, there is more than just SNPP now, NOAA20 (formerly JPSS1) launched in late 2017.

Section 4.3.3 and more generally: in this section (and elsewhere) the authors say “error” often. I think a lot of these times, they really mean “uncertainty”. For example, page 19 line 9 I think the authors mean the “uncertainty” in the DRE retrievals, not the error, since we don’t have a truth to compare to. If possible it would also be good for the authors to clarify whether the estimates they provide in the paper refer to typical levels of uncertainty (e.g. 1-sigma), maximum likely uncertainty, or similar.

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RR by Zhibo Zhang (30 Jul 2019)

ED: Publish subject to minor revisions (review by editor) (04 Aug 2019) by Hiren Jethva

AR by Martin de Graaf on behalf of the Authors (13 Aug 2019) Author's response Manuscript

ED: Publish as is (19 Aug 2019) by Hiren Jethva

AR by Martin de Graaf on behalf of the Authors (29 Aug 2019) Manuscript

Short summary

A new algorithm is described, which was used to derive direct radiative effects of aerosols above clouds. These effects are among the largest uncertainties in global climate model simulations, and observations are needed to constrain these simulations. A recently developed method was applied to a combination of satellite reflectance measurements to cover the entire shortwave (solar) spectrum. Radiative effects of aerosols over the south-east Atlantic are presented, where the effects are largest.