Applying FP_ILM to the retrieval of geometry-dependent effective Lambertian equivalent reflectivity (GE_LER) daily maps from UVN satellite measurements

Loyola, Diego G.; Xu, Jian; Heue, Klaus-Peter; Zimmer, Walter

doi:https://doi.org/10.5194/amt-13-985-2020

Articles | Volume 13, issue 2

https://doi.org/10.5194/amt-13-985-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/amt-13-985-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 13, issue 2

Research article

|

02 Mar 2020

Research article |

| 02 Mar 2020

Applying FP_ILM to the retrieval of geometry-dependent effective Lambertian equivalent reflectivity (GE_LER) daily maps from UVN satellite measurements

Diego G. Loyola, Jian Xu, Klaus-Peter Heue, and Walter Zimmer

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Final revised paper (published on 02 Mar 2020)
Preprint (discussion started on 17 Apr 2019)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'anonymous referee comment', Anonymous Referee #1, 27 May 2019
- AC1: 'Reply to referee # 1', Diego Loyola, 31 Oct 2019
RC2: 'Review of « Applying FP_ILM to the retrieval of geometry-dependent effective Lambertian equivalent reflectivity (GE_LER) to account for BRDF effects on UVN satellite measurements of trace gases, clouds and aerosols» by Loyola et al.', Anonymous Referee #2, 22 Jul 2019
- AC2: 'Reply to referee #2', Diego Loyola, 31 Oct 2019
RC3: 'Review of Diego G. Loyola, Jian Xu, Klaus-Peter Heue, Walter Zimmer, Applying FP_ILM to the retrieval of geometry-dependent effective Lambertian equivalent reflectivity (GE_LER) to account for BRDF effects on UVN satellite measurements of trace gases, clo', Anonymous Referee #3, 30 Jul 2019
- AC3: 'Reply to referee #3', Diego Loyola, 31 Oct 2019

Peer-review completion

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

AR by Diego Loyola on behalf of the Authors (23 Nov 2019)

ED: Referee Nomination & Report Request started (27 Nov 2019) by Michel Van Roozendael

RR by Anonymous Referee #1 (12 Dec 2019)

RR by Anonymous Referee #2 (13 Dec 2019)

Suggestions for revision or reasons for rejection

The authors have adequately replied to the reviewers' comments, with more discussion of the results making so the paper more robust. I have nevertheless two small comments (below) that would be nice to take into account. The paper can then be published in AMT. Congratulations to the authors for the very nice piece of work.

Comments:
- Page 10, lines 29-30: “We conclude that the historical climatologies from OMI and GOME-2 do not properly represent actual snow/ice conditions observed in 2018/2019.” This conclusion is very thin and there is no clear evidence supporting this, especially as it is ensured that pixels are well affected by snow/ice for all three instruments for the comparison. That would imply that the albedo of the snow/ice itself has changed between the current conditions and those from a few years ago, which is unlikely. I would guess that it is more related to the L1 calibration issues discussed by the authors in the reply to the reviewers, possibly leading to a high bias in the S5p albedo. In fact, if the S5p albedo was slightly lower at high latitudes, the agreement with CAMS in Fig. 13 would be slightly further improved (currently there is a low bias). Please mention in the paper the L1 version that you used and discuss the possible impact of the future L1 upgrade.
- Page 2, line 7: I still disagree with the upper limit of 35% cited here. I don’t see how the impact of the scene reflectivity uncertainty on the total ozone column, which is mostly located in the stratosphere can be that large. In fact, your Figure 12 gives a good estimate of the error by comparing the panel (f) and (d) and it seems to be around 10%. So 15% as an upper limit would be more reasonable.
- Page 12, line 28: “like Sentinel-5P” instead of “like Sentinle-5P”

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ED: Publish subject to minor revisions (review by editor) (14 Dec 2019) by Michel Van Roozendael

AR by Diego Loyola on behalf of the Authors (19 Dec 2019) Author's response

ED: Publish as is (14 Jan 2020) by Michel Van Roozendael

AR by Diego Loyola on behalf of the Authors (15 Jan 2020) Manuscript

Short summary

In this paper we present a novel algorithm for the retrieval of geometry-dependent effective Lambertian equivalent reflectivity (GE_LER) from UVN sensors based on the full-physics inverse learning machine (FP_ILM) retrieval. The GE_LER retrieval is optimized for the trace gas retrievals using the DOAS technique and the large amount of data of TROPOMI on board the EU/ESA Sentinel-5 Precursor mission.