An uncertainty-based protocol for the setup and measurement of soot–black carbon emissions from gas flares using sky-LOSA

Conrad, Bradley M.; Johnson, Matthew R.

doi:https://doi.org/10.5194/amt-14-1573-2021

Articles | Volume 14, issue 2

https://doi.org/10.5194/amt-14-1573-2021

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

https://doi.org/10.5194/amt-14-1573-2021

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

Articles | Volume 14, issue 2

Research article

|

26 Feb 2021

Research article |

| 26 Feb 2021

An uncertainty-based protocol for the setup and measurement of soot–black carbon emissions from gas flares using sky-LOSA

Bradley M. Conrad and Matthew R. Johnson

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Final revised paper (published on 26 Feb 2021)
Preprint (discussion started on 24 Aug 2020)

Interactive discussion

Status: closed

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

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- Supplement

SC1: 'Great to see these details and examples', Brian Crosland, 11 Nov 2020
RC1: 'amt-2020-255', Anonymous Referee #3, 17 Nov 2020
- AC2: 'Response to Referee #3', Bradley Conrad, 18 Dec 2020
RC2: 'Review of Conrad and Johnson 2020', Anonymous Referee #1, 21 Nov 2020
- AC1: 'Response to Referee #1', Bradley Conrad, 18 Dec 2020

Peer-review completion

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

AR by Bradley Conrad on behalf of the Authors (18 Dec 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (29 Dec 2020) by Oleg Dubovik

RR by Anonymous Referee #1 (07 Jan 2021)

Suggestions for revision or reasons for rejection

The authors Conrad and Johnson have addressed most of my feedback. I only have two comments remaining.

Length: the authors responded to my request to shorten the manuscript by stating various justifications. These should be added to the text with one or two introductory sentences. The same applies to the authors' response to my comment on the presence of non-BC impurities. Please add a brief summary to the main text.

Validation of assumptions: the authors' response to my comment (``The manuscript assumes throughout that a perfect skyLOSA measurement gives a perfect result'') was ``sky-LOSA has been validated [...] from the perspective of first principles''. The authors full response included a restatement of the bottom-up work done so far. This work is extensive and thorough, especially in the context of atmospheric measurement techniques, but does not address my comment. The purpose of my comment is to highlight that bottom-up work requires top-down validation (to the extent that such is possible).

For example, Thomson et al. (2004, https://doi.org/10.1016/j.combustflame.2004.11.012) state that ``The uncertainty of the LOSA soot volume fraction measurements is estimated to be 20 to 30% (95% confidence interval). The uncertainty is dominated by the uncertainties in the magnitude of and the contribution of scatter to light attenuation measurements.'' So the authors may add a statement such as ``The LOSA technique is estimated to be 20 to 30% accurate. We estimate that the calculation of the inscattering of solar radiation adds an additional X\% to this uncertainty using our MC technique, resulting in an overall uncertainty of Y%.'' Please add such a statement to the manuscript.

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ED: Publish subject to minor revisions (review by editor) (13 Jan 2021) by Oleg Dubovik

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

ED: Publish as is (22 Jan 2021) by Oleg Dubovik

AR by Bradley Conrad on behalf of the Authors (22 Jan 2021) Author's response Manuscript

Post-review adjustments

AA: Author's adjustment | EA: Editor approval

AA by Bradley Conrad on behalf of the Authors (24 Feb 2021) Author's adjustment Manuscript

EA: Adjustments approved (24 Feb 2021) by Oleg Dubovik

Short summary

A general uncertainty analysis (GUA) is performed for the sky-LOSA technique used to remotely measure soot emissions from gas flares. GUA data are compiled in an open-source software tool to help sky-LOSA users select critical setup and acquisition parameters while giving quantitative visual feedback on anticipated uncertainties for a specific measurement. The software tool enables easy acquisition of optimal measurement data, significantly increasing the accessibility of the sky-LOSA technique.