3-D tomographic limb sounder retrieval techniques: irregular grids and Laplacian regularisation

Krasauskas, Lukas; Ungermann, Jörn; Ensmann, Stefan; Krisch, Isabell; Kretschmer, Erik; Preusse, Peter; Riese, Martin

doi:https://doi.org/10.5194/amt-12-853-2019

Articles | Volume 12, issue 2

https://doi.org/10.5194/amt-12-853-2019

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

https://doi.org/10.5194/amt-12-853-2019

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

Articles | Volume 12, issue 2

Research article

|

07 Feb 2019

Research article |

| 07 Feb 2019

3-D tomographic limb sounder retrieval techniques: irregular grids and Laplacian regularisation

Lukas Krasauskas, Jörn Ungermann, Stefan Ensmann, Isabell Krisch, Erik Kretschmer, Peter Preusse, and Martin Riese

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Final revised paper (published on 07 Feb 2019)
Supplement to the final revised paper
Preprint (discussion started on 12 Jul 2018)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review of: Tomographic airborne limb sounder retrievals on irregular grid with second order regularisation', Anonymous Referee #1, 24 Sep 2018
- AC1: 'Response to reviewers', Lukas Krasauskas, 25 Oct 2018
RC2: 'Review of Krasauskas et al.', Anonymous Referee #2, 27 Sep 2018
- AC1: 'Response to reviewers', Lukas Krasauskas, 25 Oct 2018

Peer-review completion

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

AR by Anna Wenzel on behalf of the Authors (01 Nov 2018) Author's response

ED: Referee Nomination & Report Request started (05 Nov 2018) by Markus Rapp

RR by Anonymous Referee #2 (15 Nov 2018)

Suggestions for revision or reasons for rejection

The manuscript has been improved. It seems that all my comments have resulted in some change in the manuscript. This is appreciated. Some of the main questions are addressed by extending the manuscript with three appendices. Some extra details are provided in the author response file. I am happy with new the appendices. On the other hand, some of the changes in the main text are not fully satisfactory.

Section 2.2 is still not sufficiently clear. My assumption is that the aim is to calculate the precision matrix, and I then expected to see an equation clearly showing how the elements of the inverse if Sa are calculated. I can not identify such an equation. When reading the new manuscript I get unsure. Is it in fact only the discrete version of Eq. 13 that is evaluated? If yes, is it then not necessary to calculate the derivative of this quantity with respect to x, in order to minimise Eq. 2? I then miss an explanation of how this is done.

The first part of Sec. 3 still totally lacks references. This makes it impossible to judge if there is anything new here. At least parts are of rather a basic character and are discussed in a number of books.

I still think that it is not fair to describe older applications of Tikhonov regularisation as restricted to first order derivatives (page 2, line 10). That this is maybe true for 3D is not sufficient argument (as argued in the author response file).

It is still not clear in the manuscript how the regularisation weights for
retrieval A were set.

Some smaller issues are listed below (the list is probably not complete):

Page 2, line 9: Add ``and'' before GLORIA.

Page 4, line 5: Undefined reference.

Page 25, line 5: Same as above.

Page 5, line 13: The start of the line is not a full sentence.

Page 7, line 20: The reference to CGAL would fit better on e.g. line 2.

Page 11, line 16: Is ``adjacent'' a typo? If not, I don't understand.

Page 14, lines 7 and 8: Add ``and'' before ClONO2.

Page 15, line 11: Change ``estimate'' to ``estimated''.

Page 16, figure text: Add space before ``Panel''. Now stray ( at end of the line
3.

Page 17, line 21: Change to \citep for Krisch et al.

Page 26, line 1: Something is clearly wrong around ``below iNote''

(Some of these issues are obvious errors and I have the feeling that not all
co-authors have read the revised manuscript.)

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ED: Publish subject to minor revisions (review by editor) (16 Nov 2018) by Markus Rapp

AR by Lukas Krasauskas on behalf of the Authors (26 Nov 2018) Author's response Manuscript

ED: Publish as is (30 Nov 2018) by Markus Rapp

Short summary

Many limb sounder measurements from the same atmospheric region taken at different angles can be combined into a 3-D tomographic image of the atmosphere. Mathematically, this is a complex, computationally expensive, underdetermined problem that needs additional constraints (regularisation). We introduce an improved regularisation method based on physical properties of the atmosphere with a new irregular grid implementation. Simulated data tests show improved results and lower computational cost.