the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 04 Jul 2025
Responses of the 14 October 2023 annular solar eclipse observed in satellite temperature profiles
Abstract. On 14 October 2023, an annular solar eclipse occurred, in which, the umbra crossed part of the North Pacific, North, Central and South Americas ending over the South Atlantic ocean. On the day of the eclipse the instrument Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) on board the Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) measures temperature profiles in three orbits crossing the área of the abrangency of the eclipse. One of these orbits registered almost simultaneous events to the eclipse path over the Colombia area. Temperature data from 07 to 21 October 2023 were averaged in that region within a grid of 15° × 15° (latitude x longitude) to establish the control profile. Furthermore, comparisons to profiles observed in the days before and after were done to investigate likely instantaneous effects of the atmosphere to passage of this eclipse. The main results were changes in the temperatures producing cooling of 9–45 K in the troposphere, lower mesosphere and mesopause and warming of 7 K in the stratosphere. These results compared favourably to previous temperature observations during other eclipses and confirmed the potential of the SABER instrument to investigate transient events as solar eclipses.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Annales Geophysicae.
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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Status: final response (author comments only)
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RC1: 'Comment on egusphere-2025-3085', Martin Mlynczak, 04 Aug 2025
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AC1: 'Reply on RC1', Ana Roberta Paulino, 10 Nov 2025
Dear Dr, Bravo!
Thank you for considering our article in the Annales Geophysicae Discussions review process. Please see below our point-by-point responses to Referee 1. We would also like to thank the referee for their comments and important contributions to the improvement of our manuscript.Referee #1
Referee: "The paper is rejected on the basis that the SABER temperature data are not valid during eclipse conditions, for the reasons described in the attached full review. There is no way to revise the paper to get around this impediment nor is there any way to modify or reprocess the SABER data to improve it. Please see the full review for details. The authors are encouraged to contact the SABER team if they have questions. Martin Mlynczak, SABER Principal Investigator Emeritus."
Authors: It is an honor for us to receive feedback from one of the leading researchers of this mission. We thank you for your time, comments, concern, and the explanations involving how the measurements are made by the instrument. Although there is an explicit recommendation to reject the paper, we kindly ask for a reconsideration based on our argumentation and the clarifications we are presenting regarding the conception of the paper.
Referee:"This paper describes observations of temperature in the region from 15 km to 105 km as measured by the SABER instrument on the TIMED satellite during the annular solar eclipse event that occurred on 14 October 2023. The observations are potentially of interest to see how the Earth’s middle atmosphere responds to transient events. The authors examine SABER temperatures prior to and during the eclipse and from these observations determine the magnitude of the temperature change induced by the eclipse."
Authors: Once again, we thank you for your efforts in revising our manuscript.
Referee: "Regretfully, the paper must be rejected, but not for any fault in the analysis by the authors, but because the SABER temperature data are not suitable for analysis during eclipse events. Specifically, the SABER temperature algorithm is not designed for, and does not account for, conditions during the eclipse. As described in the papers by Mertens et al. referenced by the authors, the SABER temperature retrieval involves complex non-LTE radiative transfer calculations involving the vibration-rotation bands of carbon dioxide (CO2) in the 15-micrometer spectral region. The non-LTE processes are substantially different for day than for night in that there is substantial absorption of solar radiation by CO2 during the day and of course, none at night. Consequently, the vibrational temperatures of the 15 micrometer bands of CO2 have a strong variation from day to night. To derive the temperature correctly, the SABER radiative transfer models must first compute the correct vibrational temperatures. The algorithm used to analyze the SABER data during the eclipse is the daytime algorithm. It is not possible to switch from day to night for one or two profiles during operational processing. In addition, the SABER team has examined several eclipse conditions and found that even when near or “in” the eclipse region, the atmosphere that SABER views is almost always partly illuminated, so it is never completely in night conditions. For this reason, there is really no way for SABER to derive a valid temperature profile in or near to the eclipse region. (Note that SABER views the earth’s limb, not in the nadir, and consequently measures infrared emission over a long (~ 1000 km) path)."
Authors: We perfectly understand the referee's concern, which is quite pertinent. Eclipses are transient phenomena with a very short duration time, that is, only a few minutes. As it was very well explained in this report, SABER cannot perfectly resolve measurements within such a short time interval for the day-to-night transition. However, we would like to draw attention to the peculiarity of the eclipse that occurred on 14 October 2023. This was not a total solar eclipse i.e., it was annular with an obscuration of only around 94% of the solar disk. The amount of radiation emitted by the "ring of fire" was still sufficient to illuminate a large part of the atmosphere. Even inside the eclipse umbra, the atmosphere was still illuminated. This configuration might allow the algorithm used by SABER for day-time measurements to be efficient, and there may be no need to make changes to the algorithm. Another aspect that should be considered is that only the profile measured ∼at 14:10 is within the eclipse umbra region. The subsequent profile, at 14:15, is already outside the umbra, and the measurements quickly move away from the eclipse penumbra. If there was a significant change for the measurements in the umbra region, the more distant measurements should present very different profiles, including drastic changes in the structures, but this was not observed. In the stratosphere and troposphere regions, for example and shown in Figure 2, the profiles are well-behaved and exhibit smooth variations between successive measurements.
Referee: "Perhaps the authors might have suspected something given the magnitudes of the changes in temperature reported in their paper. For example, the 45 K decrease in 104 km might have come across as likely non-physical. Does this result mean at night the temperature would decrease by over 100 K in maybe five to ten minutes after sunset? The authors are referred to the paper by Huang et al., 2006, specifically figures 1, 2, 3, and 4.https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005JA011426. These figures show the diurnal variation of the temperature at 55 km and 95 km measured by SABER and by the Microwave Limb Sounder (MLS) on the Aura satellite. The eclipse change in temperature in a couple of minutes surely cannot be larger than the diurnal change.
Authors: Many thanks for this important comment. This temperature variation in a few minutes is really difficult to understand and even more so to relate to a possible eclipse effect. We are aware of this and are suggesting for the revised version to suppress these results from the mesosphere and lower thermosphere (MLT) region and only consider what is happening in the troposphere and stratosphere. The main reason is that in the lower atmosphere it is possible to validate the results with balloon measurements made for other eclipses. On the other hand, rapid temperature variations in the MLT happen frequently. For example, a comparison made between subsequent, randomly chosen profiles, with a difference of less than 2 minutes from one to the other—events 6 and 7 of orbit number 127540—show a change of more than 30 K at 106 km altitude. This means that in the MLT, SABER exhibits strong temperature changes in short time intervals.
Referee: "Also, it is quite likely that the warm stratosphere and the “troposphere” results at 15 km reported in the paper are likely algorithm effects due to the incorrect temperatures in the mesosphere and lower thermosphere arising from the daytime temperature algorithm being used instead of the night algorithm. Lastly, there is one other point to make regarding the SABER algorithms, for the altitudes above 80 km, which again relates to the non-LTE radiative transfer calculations. A critical input to the temperature algorithm (which is discussed in the Mertens et al. papers) is the atomic oxygen concentration. SABER’s temperature algorithm uses atomic oxygen provided by the MSIS-2000 empirical model. As such, the atomic oxygen concentration from the empirical model cannot be expected to be correct if there are rapidly changing conditions to be properly modeled. This fact, in addition to the daytime/nighttime issues mentioned above, likely leads to the large and almost surely incorrect temperature changes reported in the paper."
Authors: The reviewer has sufficient expertise to raise these possibilities since they are part of the team that performed the entire construction of the mission, including the algorithms for obtaining the temperature. We would just like to point out that cooling in the troposphere and warming in the stratosphere during eclipse passages have been reported in several scientific campaigns. Therefore, what is being observed in the SABER profiles for these regions has scientific support. For this reason, we are proposing a revised version of the paper that considers only these regions (troposphere and stratosphere) so that the discussion is more substantial. Furthermore, the work by Basha et al. (2025, published after the submission of this manuscript), which used COSMIC profiles to study effect of the 8 April 2024 solar eclipse, showed cooling in the troposphere and warming in the stratosphere compatible in both altitude and amplitude with what is being presented in this manuscript.
Once again, we perfectly understand the reviewer's concern and agree with the attention that must be given due to the observational limitations of SABER. At the same time, the dynamics of the satellite in measuring the temperature and the constant presence of the "ring of fire" (annular eclipse) that illuminated the atmosphere during the passage lead us to believe that the results presented in this work for the troposphere and stratosphere regions have potential to provide a plausible idea of the atmosphere's response to this event.
Referee: "In closing, the authors are encouraged to reach out to the SABER team if they have further questions about the validity and utility of the data during transient events."
Authors: It will always be a pleasure for us to interact with the SABER team, which provides excellent services to the scientific community and is always willing to contribute to the analysis and interpretation of the data. We are very grateful for the online availability of the data and want to expand this discussion with the revised version of the manuscript, which will consider all of the reviewer's recommendations.
References
Basha, G.; Ratnam, M.V.; Jiang, J.H.; Pangaluru, K. Investigating the Effects of the Solar Eclipse on the Atmosphere over Land and Oceanic Regions: Observations from Ground Stations and COSMIC2 Data. Atmosphere 2025, 16, 872. https://doi.org/10.3390/atmos16070872.Citation: https://doi.org/10.5194/egusphere-2025-3085-AC1
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AC1: 'Reply on RC1', Ana Roberta Paulino, 10 Nov 2025
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RC2: 'Comment on egusphere-2025-3085', Anonymous Referee #2, 09 Sep 2025
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AC2: 'Reply on RC2', Ana Roberta Paulino, 11 Nov 2025
Prezado Dr. Bravo!
Thank you for considering our article in the Annales Geophysicae Discussions review process. Please see below our point-by-point responses to Referee 2. We would also like to thank the referee for their comments and important contributions to the improvement of our manuscript.
Referee #2
Referee: "1. The text is not easy to read because of many sentences that provide an ambiguity of interpretations. I strongly recommend revising all the manuscript with a critical eye. Please use the accepted scientific terms introducing them at first mentioning. Please be more specific about every detail you provide. I recommend paying attention to the formulation of the sentences and avoiding a plain language. Please see my specific comments."
Authors: Thank you very much for the careful revision and for all the suggested corrections. All suggestions will be incorporated into the revised version of the manuscript. We apologize for any language and semantic errors that may have made your reading difficult.
Referee: "Introduction section. Please state clearly the aim of this study and the tasks to be resolved. Please avoid putting the results in Introduction (lines 38-40)."
Authors: Thank you for the suggestion, we will revise the Introduction accordingly.
Referee: "Reference values. - An explanation is needed, why exactly 14 days of data (some of which were before and some after the eclipse) were chosen to reveal the regular tendencies? - Is there any systematic variation corresponding to 14 days interval, which should be taken into account? - These days are not “quiet reference days”. I see at least weak and moderate magnetic field disturbances during this period. My recommendation is to check any other natural events that could perturb the atmosphere during this period. - Why the average values are taken as a quiet reference? I would probably incline at least to a median value as, in contrast to the average, it is not affected by disturbances."
Authors: The basic idea is to try and remove day-to-day variations. This average profile should serve as a reference. It is noted that there is a very large variability, especially in the Mesosphere and Lower Thermosphere (MLT) region. There is no exact reason for choosing 14 days, but we believe it is a sufficient number of days for the purpose of building an average profile that excludes day-to-day variations. No assessment was made about possible oscillations of a few days, however, this would not be a problem for this type of analysis, since the intention is to see what is happening between adjacent profiles. The important aspect of these comparisons is to show that the changes on 14 October 2023 do not happen on other days in order to relate the variations to possible atmospheric responses to the eclipse passage. For the lower atmosphere, the effects of magnetic storms should not be relevant. The use of a median instead of the mean might also be interesting, we will perform the tests to respond to it with more certainty in the revised version.
Referee: "4. The moments of temperature decrease/increase should be corresponded to the eclipse parameters. At which phase of the eclipse the particular effect was observed? Or was it before or after? Why?"
Authors: A perfect temporal and spatial synchronism occurred, meaning the cooling (troposphere) and heating (stratosphere) are amplified in the profiles close to the umbra region and tend to decrease for regions far away from the umbra, which also had profiles measured at later times. For measurements taken at long distances along the same orbit, the patterns tend to re-establish to what was observed before the eclipse passage. We will detail these results further in the revised version of the manuscript.
Referee: "5. Lines 127-128: 'random enhancements in the days after and before the eclipse could also be seen. Thus, it is not easy to make a direct association of this enhancement to the solar eclipse.' I disagree. Why the authors think that the enhancements on other days were random? Did you check regular temperature variations in the region of the study? What are they? What is the limit of day-to-day variability in this season? What are the possible reasons for enhancements? Can we check and discard some of them? It is possible to associate some irregular atmospheric behaviour during the eclipse while knowing regular variations and the particular agents that can induce some temperature changes."
Authors: The referee is right, this sentence needs to be reviewed and rewritten. The idea of this discussion is to show that there is no well-defined and systematic pattern with temporal and spatial synchronism for the variations in the temperature profiles measured on days before and after the passage of the eclipse. This greatly strengthens the argument about possible effects of the eclipse on the atmosphere. We understand that there may be other patterns that are not as random as the reviewer pointed out, but which are not relevant to what is proposed in the scope of this work.
Referee: "6. Line 129: 'middle stratosphere was poorly explored in the previous publication' – I am not sure what previous work is referred to. Why it was not studied in the present work at least with the same SABER instrument or may be some model? The authors stress the need to do it in lines 133-136."
Authors: We meant to say that few publications have investigated this region of the atmosphere, especially using atmospheric sounding data. In the revised version, we will rewrite this sentence better and improve the argumentation.
Referee: "7. Conclusions. The last sentence introduces uncertainty: were the temperature disturbances triggered by the eclipse passage or not? The discussion should be developed: - What says in favor to the positive response to this question? - What is the physical mechanism? Is it only the decrease in radiation from the Sun or some other factors? Is the physics of temperature change is the same at different heights? - Do the rates of change correspond somehow to the eclipse parameters at different heights (obscuration rate, the speed with which the shadow passes, the direction of movement of the shadow in relation to the movement of the satellite or any other factor)? - Do the season and the local time play some role in the middle atmosphere response to the eclipse? - What new features are added to current understanding of temperature variations or what known features were confirmed/précised by the obtained results?
Authors: Thank you for the important suggestions. We will revise the manuscript in both the conclusion and the discussion in an attempt to address all of the reviewer's concerns.
Referee: "Specific comments (examples)" and "Minor comments"
Authors: "We appreciate the referee's quite careful review, which will help us present a more refined and consistent version of the manuscript. All of the referee's considerations will be promptly addressed for the new version of the manuscript."Citation: https://doi.org/10.5194/egusphere-2025-3085-AC2
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AC2: 'Reply on RC2', Ana Roberta Paulino, 11 Nov 2025
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The paper is rejected on the basis that the SABER temperature data are not valid during eclipse conditions, for the reasons described in the attached full review. There is no way to revise the paper to get around this impediment nor is there any way to modify or reprocess the SABER data to improve it. Please see the full review for details. The authors are encouraged to contact the SABER team if they have questions. Martin Mlynczak, SABER Principal Investigator Emeritus.