the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 12 May 2025
Stratospheric and upper tropospheric measurements of long-lived tracers and photochemically active species with GLORIA-B
Abstract. The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is a limb-imaging Fourier-Transform Spectrometer (iFTS) providing high-resolution mid-infrared spectra in the 780–1400 cm-1 wavenumber range. Originally designed for aircraft, GLORIA has been deployed in eight research campaigns to date. To extend its observational range from the middle troposphere to the middle stratosphere, the instrument was adapted for a stratospheric balloon platform. GLORIA-B completed its first flight from Kiruna (Sweden) in August 2021 and a second from Timmins (Canada) in August 2022 as part of the EU Research Infrastructure HEMERA. The main objectives of these flights were technical qualification and the provision of a first imaging hyperspectral limb-emission dataset from 5 to 36 km altitude. This study evaluates the performance of GLORIA-B using vertical volume mixing ratio (VMR) profiles from the August 2021 flight, focusing on trace gases like O3, CH4, CFCs, HCFC-22, and SF6. Comparisons with in-situ measurements (ozonesonde, MegaAirCore, and cryosampler) show agreement within 10 % for O3, CH4, SF6, and CFC-12, and within 10-20 % for CFC-11, HCFC-22, and CFC-113 up to 18 km, with larger deviations above this altitude. Another objective is analyzing diurnal changes in photochemically active species (N2O5, NO2, ClONO2, BrONO2). Observed VMR variations align well with simulations from the EMAC (ECHAM5/MESSy Atmospheric Chemistry) chemistry-climate model, though absolute concentrations differ to a certain extent. Using the nighttime BrONO2-to-Bry ratio from simulations, the observed lower stratospheric Bry amount was estimated to 20.4 ± 2.5 pptv. In summary, the successful deployment of GLORIA on a stratospheric balloon platform has demonstrated the capability of the limb-imaging technique to provide high-quality vertical trace gas profiles up to the middle stratosphere, contributing to a better understanding of the distribution and temporal evolution of key atmospheric species.
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
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RC1: 'Comment on egusphere-2025-1838', Anonymous Referee #1, 11 Jun 2025
A Review of “Stratospheric and upper tropospheric measurements of long-lived tracers and photochemically active species with GLORIA-B” by G. Wetzel et al.
< General Comments >
This paper describes the first result of GLORIA-B flight from Kiruna in 2021. The paper is generally well written and the contents which are described in the paper is clear. I felt the paper is almost worth published in Atmospheric Measurement Techniques. I have only a few minor points which would be nice to be modified before publication, which is pointed out below.
< Minor Comments >
1) P.1, L.31: What is “HEMERA”? Please provide what it means for.
2) P.22, L.510: “a clear negative bias is evident in the cryosampler VMR.” What is the cause of this negative bias? Please give some idea for this bias.
3) P.23, L.539-540: What is the meaning of the sentence? “The vertical shape of the observed profiles is largely as expected.” I guess some word(s) are missing.
Citation: https://doi.org/10.5194/egusphere-2025-1838-RC1 -
AC1: 'Reply on RC1', Gerald Wetzel, 03 Sep 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-1838/egusphere-2025-1838-AC1-supplement.pdf
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AC1: 'Reply on RC1', Gerald Wetzel, 03 Sep 2025
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RC2: 'Comment on egusphere-2025-1838', Anonymous Referee #2, 11 Jul 2025
GLORIA-B is the balloon adapted version of the GLORIA instrument. Wetzel et al. describe in their manuscript the GLORIA-B instrument and present the first measurements that have been made with GLORIA-B during the HEMERA campaigns in August 2021 and 2022. The during these campaigns derived GLORIA-B measurements are compared with in-situ measurements from e.g. MegaAirCore and with model simulations from EMAC. The comparisons presented in Wetzel et al. show that the observations from MIPAS-B have are in good agreement with in-situ measurements and that the temporal evolution of the measured trace gases is in agreement with model simulations from EMAC.
The manuscript is well written and the presented results worth to be published. I have only some suggestions for minor revisions that I think will improve the manuscript.
Specific comments:
P1, Title: The title is too general and does not really reflect what is the main purpose of the study. To my understanding this is the first publication on GLORIA-B and thus the instrument is here presented and validated for the first time. This should be clearly reflected in the title.
P1, Abstract: Also the abstract should be revised. The current version reads like a summary rather than an abstract. I would suggest to add a general sentence to motivate why such measurements are needed. Also add some sentences on what has been done and what the main purpose of this study is (characterization and validation of GLORIA-B). Then you can provide a short summary of the major findings (good agreement with other measurement and model simulation) and then conclude what benefit the scientific community has from such kind of measurements.
P1, L31: The abbreviation HEMERA needs to be introduced.
P3, L71: “some time” is a bit vague. Can you provide some numbers?
P3, L80: From this statement I understand that this is the first publication on GLORIA-B. Is that is the such a statement should already appear in the abstract.
P3, L80-85: Actually that paragraph I would have rather expected in the abstract than in the introduction. It is fine to have it in both, but definitely some sentences like these should be found in the abstract. In general your abstract provide all necessary information, but the message gets not that easily and clearly through as it is the case in this paragraph.
P12, L326: This altitude? Which altitude exactly? 40 km? Add the altitude so that it is clear which altitude is meant.
P14, Numbers: For the spectral ranges, I would suggest to use only two digits after the comma for better readability.
P15, L372: Add a header “Results” to be more clear that from here on the description of the results starts?
P24, L549 and P25, L564: On P24 you write that you will demonstrate that GLORIA is able to measure the temporal evolution of trace gases by comparing to model simulations on P25 however you write that EMAC is able to reproduce the observations. Are you now evaluating the model or the observations? Check that you have a consistent way of writing/discussing the results in this section.
P29, Figure 16: I would suggest to use another color than cyan since it is hardly visible. Use a somewhat darker color.
P29, L617: Here a statement or a reference if these are realistic results or not is missing.
P30, L650ff: In the conclusions you clearly write that there are also differences and areas where the results are not that perfect. When reading the result section I had the feeling that the results are solely good. Check for consistency and also mention in the respective result subsections where and when deviations occur.
P31, L658: “significantly larger” -> please quantify
P31, L668: This statement is a bit contradicting to what has said before. Of course with your measurements you can improve models, but your motivation for showing comparisons to model simulations was to show that GLORIA-B can measure the temporal evolution of the trace gases.
Technical corrections:
P3, L67: Add “the” so that it reads the “Global Ozone Monitoring……”?
P6, L141: Remove colon after subsection title.
P7, L154: Same here as for P6, L141.
P9, L239: or the lower part of the gondola -> or “the” lower part of the gondola?
P12, L304: 21/22 August -> 21-22 August 2021
P12, L319: Use also capital letters for the written out version of HITRAN? For KOPRA this is done.
P12, L328: Are the digits after the comma needed? For better readability I would suggest to omit these.
P13, L344: 21/22 -> 21-22 (this should also be corrected in the figures)
P14, Table 1 caption: alt. reso. In parenthesis obsolete. This is also without writing this clear. However, I would in the table header abbreviate resolution with res. Instead of reso.
Figure 7 and other figures of this kind: On a printed version the squares in the legend are hardly visible and in the figure itself I can see them neither in the printed version nor in the pdf version.
P31, L672: Add “published” so that it reads “is published on Zenodo”.
Citation: https://doi.org/10.5194/egusphere-2025-1838-RC2 -
AC2: 'Reply on RC2', Gerald Wetzel, 03 Sep 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-1838/egusphere-2025-1838-AC2-supplement.pdf
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AC2: 'Reply on RC2', Gerald Wetzel, 03 Sep 2025
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