the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 06 Feb 2026
Evaluating SCIAMACHY-retrieved and ECHAM-simulated stratospheric aerosol characteristics by their comparison after volcanic eruptions
Abstract. Satellite observations and global aerosol–micropysical model simulations are essential to study the impact of volcanic aerosols on stratospheric composition and dynamics. However, despite their continuous improvements, uncertainties remain in satellite retrievals and model outputs due to assumptions about aerosol size, composition, and simplified model parameterizations. The SCIAMACHY v2.0 PSD algorithm for obtaining stratospheric aerosol characteristics assumes a fixed particle number density profile representative of background conditions. MAECHAM5-HAM simulations employ parameterized aerosol microphysics and chemistry. Both approaches might be affected by increased uncertainties after volcanically perturbed situations. We compare SCIAMACHY v2.0 PSD aerosol extinction coefficient and effective radius profiles with MAECHAM5-HAM simulations following the Manam (2004/2005) and Sarychev (2009) eruptions to evaluate both data products. SCIAMACHY retrievals and MAECHAM5-HAM simulations show strong consistency for the Sarychev eruption in plume location, particle growth within the plume, and size reduction at plume boarder. In contrast, SCIAMACHY observes the Manam plume further north, with differences in aerosol size evolution compared to MAECHAM5-HAM simulations. Additional comparisons with SAGE II and alternative SCIAMACHY retrievals after the Manam eruption confirm that the v2.0 PSD approach provides the most realistic aerosol characteristics from SCIAMACHY. A model parameter study highlights the importance of accurate background aerosol size information, its parameterization, and vertical injection profiles for realistic simulations of volcanic plumes. Nudging MAECHAM5-HAM with ERA5 reanalyis data improves the simulated atmospheric dynamics and brings the simulation output closer to observations. Increasing the horizontal injection area compensates for under-represented chemical interactions involving OH and volcanic ash. These findings provide valuable insights for improving the simulations of volcanic eruptions with aerosol-microphysical models and enhancing the interpretation of satellite-based aerosol data.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Atmospheric Measurement Techniques.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.- Preprint
(6805 KB) - Metadata XML
- BibTeX
- EndNote
Status: final response (author comments only)
-
RC1: 'Comment on egusphere-2026-578', Anonymous Referee #1, 17 Mar 2026
-
AC1: 'Reply on RC1', Christine Pohl, 18 Sep 2026
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2026/egusphere-2026-578/egusphere-2026-578-AC1-supplement.pdf
-
AC1: 'Reply on RC1', Christine Pohl, 18 Sep 2026
-
RC2: 'Comment on egusphere-2026-578', Anonymous Referee #2, 23 May 2026
Overall review:
This manuscript presents a comparison study between various global circulation models and satellite measurements made. This study focuses on comparing modeling and satellite observation data for stratospheric aerosol emitted from several volcanic eruptions. There is clear scientific merit presented in this study but the authors do not clearly motivate their claims or justify their stated significance with results. They do not present an inter-comparison with satellite observations, but those comparisons are not quantified and only discussed in passing. Additionally, the satellite results are assumed to be uncertain without justification. In no part of the comparison is there a discussion or quantification of data agreement. There needs to be a quantification of how the data are comparing. The organization of the paper is clear, but there are various typos in the figure cations and there is not clear demonstration as to how they are judging data agreement. Â Currently their is no quantifiable justification for their abstract statement. I recommend major revision. Below are general comments and suggested changes. In addition to general comments and suggestions, I have also made specific comments and suggestions within the attached manuscript PDF file.Â
General comments:
The following aspects are those considered important by AMT for review:
1. Does the paper address relevant scientific questions within the scope of AMT? This work is an inter-comparison of modeling data and satellite observations. As such, this is well within the scope of AMT.
2. Does the paper present novel concepts, ideas, tools, or data? It does not make any claims that this is a novel method. I am taking it as a given that this model is unique. The comparisons with volcanic observations does seem unique.
3. Are substantial conclusions reached? No quantifiable conclusions are made.
4. Are the scientific methods and assumptions valid and clearly outlined? The authors do define their methods and assumptions.5. Are the results sufficient to support the interpretations and conclusions? The do not quantify their results with and statistics or clarity. Most of their statements are vague and unclear.
6. Is the description of experiments and calculations sufficiently complete and precise to allow their reproduction by fellow scientists (traceability of results)? Not really. There would be no way for someone to replicate their results.
7. Do the authors give proper credit to related work and clearly indicate their own new/original contribution? The authors do seem to represent their citations accurately.
8. Does the title clearly reflect the contents of the paper? The title does correctly represent the manuscript’s contents. No suggestions.
9. Does the abstract provide a concise and complete summary? The abstract claims are concise but not represented well in the manuscript’s contents. Suggest clearly quantifying the claimed results and altering the abstract to align with the manuscript.
10. Is the overall presentation well structured and clear? In general, the work is structured appropriately but the comparisons seems unclear.
11. Is the language fluent and precise? There are some errors and typos, but the language is reasonable but not precise. Plenty statements of good agreement but no quantification is given to justify the language.
12. Are mathematical formulae, symbols, abbreviations, and units correctly defined and used? There are some small issues but generally, the mathematical formulae, symbols, abbreviations, and units correctly defined and used.
13. Should any parts of the paper (text, formulae, figures, tables) be clarified, reduced, combined, or eliminated? Most of the text needs to be changed to include specific discussion of quantifying how different metrics agree.
14. Are the number and quality of references appropriate? There is an appropriate number and quality of references.
15. Is the amount and quality of supplementary material appropriate? This is not applicable.-
AC2: 'Reply on RC2', Christine Pohl, 18 Sep 2026
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2026/egusphere-2026-578/egusphere-2026-578-AC2-supplement.pdf
-
AC2: 'Reply on RC2', Christine Pohl, 18 Sep 2026
Viewed
| HTML | XML | Total | BibTeX | EndNote | |
|---|---|---|---|---|---|
| 1,044 | 450 | 116 | 1,610 | 260 | 305 |
- HTML: 1,044
- PDF: 450
- XML: 116
- Total: 1,610
- BibTeX: 260
- EndNote: 305
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
In the paper “Evaluating SCIAMACHY-retrieved and ECHAM-simulated stratospheric aerosol characteristics by their comparison after volcanic eruptions” the authors have looked at three different SCIAMACHY-retrieved aerosol data products (v2.0 PSD, SCIA PSD N_WY and v3.0), SAGE II measurements and multiple configurations of the ECHAM model with the goal of demonstrating the usefulness of the SCIAMACHY v2.0 PSD aerosol product. Retrieval of aerosol information in the stratosphere from limb looking instrumentation is challenging and this paper provides useful information related to both the v2.0 data product, and the ECHAM model and how it can be used alongside the measurements to inform on their quality. In the end the authors conclude “This makes the SCIAMACHY v2.0 PSD a valuable data resources, …”, and I agree. Although the work is not definitive, it belongs in the open literature as it adds yet another piece to the puzzle. Because they speak truth, the last two sentences of the paper explain very nicely why I agree with the value attributed by the authors to the data product. I suggest this paper be accepted with a few revisions/suggestions that I feel are not onerous.Â
Suggestions
Although I like the synergistic use of the model and the measurements, it seems to me that it could be perceived that the outcome of the study may have been predetermined and that the methodology and analysis were designed to get to the desired result. I would suggest that the authors spend a little time convincing the reader that tweaking the model parameters, so the model agreed well with the other two data products wasn’t the right way to go. I understand the authors feel more confident with the v2.0 data product, but the reader could maybe use a little more convincing that it was the clear choice.
I am not overly familiar with the model parameters that were tweaked and although I think the authors addressed the impact of changes to the parameters, I don’t have the background to fully understand these impacts. I would ask the authors to revisit this section with a view toward the measurement community. Is it possible to add a few more sentence, or a paragraph or two, to assure the measurement community that the model is not just being tweaked to make the measurements look better? The shortcoming may be with me, so I trust the authors to add these extra words only if they are necessary.
I am curious as to what was learned about the other two data products used within this study. If the authors have anything to say about future work with these products, a paragraph devoted to them in the Conclusions would be useful.
Summary
I would like to thank the authors for their contribution to an interesting and challenging area of research. Keep up the good work.