Articles | Volume 18, issue 20
https://doi.org/10.5194/amt-18-5619-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.Extension of the Complete Data Fusion algorithm to tomographic retrieval products
Download
- Final revised paper (published on 21 Oct 2025)
- Preprint (discussion started on 28 Mar 2025)
Interactive discussion
Status: closed
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor
| : Report abuse
-
RC1: 'Comment on egusphere-2025-1283', Anonymous Referee #1, 30 Apr 2025
- AC1: 'Reply on RC1', Cecilia Tirelli, 20 Aug 2025
-
RC2: 'Comment on egusphere-2025-1283', Anonymous Referee #2, 02 Jul 2025
- AC2: 'Reply on RC2', Cecilia Tirelli, 20 Aug 2025
Peer review completion
AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
AR by Cecilia Tirelli on behalf of the Authors (20 Aug 2025)
Author's response
Author's tracked changes
Manuscript
ED: Publish subject to technical corrections (02 Sep 2025) by Mark Weber

AR by Cecilia Tirelli on behalf of the Authors (04 Sep 2025)
Author's response
Manuscript
Tirelli et al. in this work propose an extension of the Complete Data Fusion framework to tomographic atmospheric retrieval products that are both vertically and horizontally resolved. In preparation for ESA’s EE11 candidate mission CAIRT, this work provides promising new results. Their presentation, however, could be improved, in terms of readability as well as on the technical implementation of the multidimensional CDF.
General comments:
Abstract and introduction (especially lines 32-33): The statement that CDF has been “used so far to combine only one-dimensional atmospheric products (vertical profiles) from simultaneous and independent remote sensing observations of the same air mass” might be confusing, given that several 1D profiles within a certain spatiotemporal extent (e.g. L3 data grid) can be fused, so (exactly) the same air mass sounds too strong. Brief Section 2.1 is clearer on this and might therefore rather be part of the introduction. With that, the difference should be explained between the tomographic retrieval and an along-track curtain of nadir observations, in terms of retrieval and its information characteristics (i.e. the former having vertical and horizontal information smoothing and covariances).
Section 6: Having subsections for the discussion of the three cases would improve readability, but, more importantly, schematic drawings of the spatial configuration of the measurements that are combined in the three cases would provide a better understanding. Moreover, case 1 does not seem to be fully representative, not only because of its dimensionality, but also as the fused product is fully dominated by CAIRT (Figure 1). This should be appropriately discussed (instead of being just mentioned in lines 287-288), also in view of the DFS differences between Tables 1 and 2, which are minor for CAIRT (how?) but substantial for IASI-NG.
It seems inappropriate and misleading to indicate the fused DFS to have a ‘gain’ or X times higher DFS than the individual products, as this largely depends on the number of profiles involved, rather than on the fusion performance.
The CAIRT AKM diagonal in Figure 2 (middle-left) looks interesting but lacks explanation. Could you elaborate on the ‘smile’ shape of the information between 10 and 20 km, and on the offset of the vertical information towards positive along-track distances (closer to CAIRT)? It could then be clarified from the configuration difference why these features are missing in Figure 4 for the third case. Here, the color scale should be updated to avoid saturation. Why keep the same color scale for the AKM diagonals between Figures 2 and 4, and not for the errors, wherefrom it would be clearer that the IASI-NG total errors in Figures 2 and 4 are the same?
Lines 338-339: “Thus, the results shown in Fig. 5 are the same for all the 21 ALT positions.” Is this exactly the same, or by approximation?
Please provide a physical or information-wise interpretation of the synergy factors defined in Equations (21) and (22).
Lines 396-400: Although an attempt is made to explain the origin of the IASI-NG horizontal resolution estimates, this is not clear from the current description.
Technical corrections:
Line 19: Referring only to Aires (2011, 2012) here seems too limited.
Line 44: The meaning of “referred to different true profiles” is not clear here. Does this mean “not covering exactly the same air mass” here?
Appropriate referencing is missing in Section 3.1.
Lines 148-149: To my understanding, the age of air does not equal “the time needed by a tropospheric air parcel to reach the stratosphere”
Line 196: “monochromatic radiance” There should be several of these at least? Please explain.
Lines 204-213: This paragraph contains several unexplained abbreviations.
Line 211: Why 1.4 km? Please explain.
Line 223: Although well-explained, ALT is a somewhat confusing abbreviation for the along-track position, as it is often used for the vertical (altitude) dimension.
Line 342: Which layers?
Data availability: Possibly the reader can already be referred to the foreseen IASI-NG and CAIRT data archives, if already existing?