the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 20 Jul 2026
Simulation of Atmospheric Ozone Layer Formation and Study on the Influence of Equatorial Atmospheric Vertical Motion on the Ozone Layer
Abstract. Stratospheric ozone is crucial for protecting terrestrial ecosystems and maintaining climate stability by absorbing solar ultraviolet radiation. Its distribution is jointly determined by photochemical reactions and atmospheric dynamic processes. Equatorial vertical motion, as a key component of global circulation, profoundly influences ozone production and depletion by regulating precursor transport, photolysis rates, and temperature fields. Based on the Chapman mechanism and catalytic reaction theory, this study establishes a photochemical-dynamic coupled numerical model covering the surface to 500 km, simulating the formation process of the equatorial ozone layer. Through multiple controlled experiments, the effects of vertical motions with different intensities are systematically quantified. Results demonstrate that vertical motion significantly reshapes the steady state and structure of the ozone layer: stronger motion leads to reduced ozone layer thickness, elevated concentration peak altitude, and a transition from multi-peak to nearly single-peak vertical distribution. Notably, the simulations reveal for the first time that in the absence of external dynamic forcing apart from Earth’s revolution around the Sun and its rotation, the ozone system itself exhibits an intrinsic oscillation period of approximately 31 months. Based on this finding, we propose a novel scientific hypothesis: this intrinsic period may serve as a "baseline frequency anchor" that facilitates research on the periods of the stratospheric Quasi-Biennial Oscillation (QBO) and the Tropospheric Biennial Oscillation (TBO). This suggests that the ozone layer may not be merely a passive responder within the climate system, but rather an active component with autonomous oscillation capability capable of modulating atmospheric circulation through radiative feedbacks. This study provides new numerical evidence and theoretical perspectives for understanding the spatiotemporal evolution of the ozone layer and stratosphere-troposphere interactions.
Status: open (until 31 Aug 2026)
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RC1: 'Comment on egusphere-2026-3004', Anonymous Referee #1, 20 Jul 2026
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AC1: 'Reply on RC1', Xiangping xiao, 30 Jul 2026
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Dear Reviewer,
We sincerely appreciate your thorough and professional comments, which have been extremely helpful in improving our work. Before preparing this response, we conducted additional simulations over several days to examine the ozone evolution under conditions with zero residual vertical velocity and only perturbative motions. Our detailed responses to each point are provided below.
- Experimental design lacks sufficient detail for reproducibility.
We fully agree that the experimental setup must be described with adequate precision. In the revised manuscript, we will specify that the stiff ODE system is solved using the Radau method (via scipy.integrate.solve_ivp), with the relative tolerance set to 1e-6 and absolute tolerance to 1e-11. The solution is saved at halfhourly intervals.
The simulation starts at the vernal equinox of 2025 (i.e., 17:01:00 UTC on March 20). The atmosphere is divided into 47 vertical levels, with layer heights as follows: [500000, 460000, 420000, 380000, 340000, 300000, 260000, 220000, 190000, 170000, 150000, 130000, 110000, 94000, 82000, 70000, 62000, 57000, 53000, 50000, 45000, 41000, 37000, 35000, 33000, 32000, 31000, 30000, 29000, 28000, 27000, 25000, 23000, 21000, 19000, 18000, 17000, 16000, 15000, 13000, 11000, 9000, 7000, 5000, 2000, 1000, 0]. The simulation data for the quiescent (no vertical motion) case are provided in the attachment.
- Results section formatting and figure quality; reference error (I.P. Gibel).
Figures: We acknowledge that the figures in the submitted version suffered from reduced resolution during document compilation. We will provide all original highresolution figures to ACP when demanded.
References: We regret the citation error regarding I.P. Gibel. This error occurred because we directly copied the citation from another paper without verifying the original author's name after downloading and reading the source article. We have now carefully checked all other references one by one and confirmed that no similar issues exist. The incorrect entry has been corrected.
- Model top at 500 km vs. ozone peak at ~40 km; justification for extending beyond 100 km.
We appreciate this comment. Our rationale for including altitudes above 100 km is that, although the atmosphere is extremely tenuous at these levels, it still absorbs a portion of solar radiation—particularly in the extreme ultraviolet (EUV) bands. While the conventional "edge of space" is often defined at ~100 km, we believe that including the upper layers improves the physical completeness of the radiative transfer calculation and yields results that more closely resemble real atmospheric conditions.
- Discrepancies in vertical velocity magnitudes and unrealistically high total column ozone (TCO) under no vertical motion (~2500 DU vs. observed ~300 DU).
We thank the reviewer for raising these critical issues. We offer the following clarifications and describe the additional work we have undertaken in response:
The velocities we referred to are not the residual BrewerDobson circulation velocities, but rather a combined vertical velocity that includes both advective and perturbative components. We realise that our previous wording was ambiguous and may have caused confusion. This will be improved in the revised manuscript.
In direct response to the reviewer's concern, we performed additional simulations over the past few days. These experiments show that even when the residual vertical circulation is set to zero, the inclusion of perturbative vertical velocities(ranges from 1 to 7 mm/s[1]) alone leads to a substantial reduction in TCO. Moreover, when tropopauselevel exchange (where vertical speeds can reach up to 15 m/s [2]) is considered, the TCO decreases even more significantly. These new results will be incorporated into the revised manuscript to provide a more comprehensive sensitivity analysis.
Nomotion baseline (2550 DU): We fully agree that this value is far higher than the observed global mean (~300 DU). However, the static atmosphere is a purely hypothetical baseline, not a realistic scenario. The key contribution of our work is to quantify the relationship between vertical motion and TCO reduction. Our simulations reveal a nearperfect logarithmic negative correlation (correlation coefficient close to −1) between vertical velocity and TCO, which we consider a novel and robust finding. In the updated version, we will present this scaling relationship more clearly and emphasise that the baseline itself is not intended to represent a physical state.
Observational support from ENSO: The negative correlation we identified is also strongly supported by observational evidence during El Niño events. During the 1997–1998 El Niño, equatorial TCO dropped to 200–225 DU, with a distinct "seesaw" pattern: ozone negative anomalies coincided with uppertropospheric (200 hPa) divergence zones (e.g., eastern Pacific, eastern Africa), while positive anomalies aligned with convergence zones (e.g., western Pacific, eastern Indian Ocean)[3]. More recently, Jingyu Li et al. [4] confirmed that ENSO induces an eastwest dipole response in tropical tropospheric column ozone: during El Niño, TCO significantly decreases over the centraleastern Pacific and increases over the western Pacific. These observed patterns are fully consistent with our modelled negative correlation between vertical motion and ozone abundance, and we will expand this discussion in the revised paper to better contextualise our findings.
We are genuinely grateful for the reviewer's insightful and constructive comments. Your feedback has already significantly strengthened our work, and we hope that the clarifications and additional simulation results provided above adequately address your concerns. We look forward to the opportunity to receive further valuable suggestions that will help us improve the manuscript to the standard expected by ACP.
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AC2: 'The references in the previous reply(Reply on AC1)', Xiangping xiao, 30 Jul 2026
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References:
[1] Sakazaki, T., T. Sasaki, M. Shiotani, Y. Tomikawa, and D. Kinnison (2015), Zonally uniform tidal oscillations in the tropical stratosphere, Geophys. Res. Lett., 42, 9553–9560, doi:10.1002/ 2015GL066054.
[2] Kumar, K. K. (2006), VHF radar observations of convectively generated gravity waves: Some new insights, Geophys. Res. Lett., 33, L01815, doi:10.1029/2005GL024109.
[3] Chernikov, A. A., Borisov, Y. A., & Zvyagintsev, A. M. The Impact of the 1997–1998 El Niño Event on the Earth's Ozone Layer. Meteorologiya i Gidrologiya, (in Russian). (translatedinto Chinese in Meteorological Science and Technology, 1998, No. 3, pp. 46-49)
[4] Jingyu Li, Haolin Wang, Qi Fan, and Xiao Lu, Tropospheric ozone responses to the El Niño–Southern Oscillation (ENSO): quantification of individual processes and future projections from multiple chemical models. Chem. Phys., 25, 12983–13006. 10.5194/acp-25-12983-2025(2025).
Citation: https://doi.org/10.5194/egusphere-2026-3004-AC2
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AC1: 'Reply on RC1', Xiangping xiao, 30 Jul 2026
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RC2: 'Comment on egusphere-2026-3004', Anonymous Referee #2, 14 Aug 2026
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The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2026/egusphere-2026-3004/egusphere-2026-3004-RC2-supplement.pdf
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This paper attempts to study the ozone layer formation and the influence of vertical model on ozone. This paper does not meet the standards I would expect of a credible scientific work submitted to ACP as a preprint.
Main criticisms:
- The experimental design section does not include enough detail for this study to be reproducible.
- The results section consists of a series of poorly formatted bullet points and low resolution figures. The references have not been checked. I.P. Gibel is not the correct author for the paper listed.
- The model top is at 500 km with 47 vertical levels. Ozone concentrations peak at about 40 km. There is little justification for studying beyond ~100 km (conventional definition of the edge of space).
- Many values seem to be off by an order of magnitude. For example, the authors claim that " Vertical velocities in the stratosphere typically range from 0.3–2 cm/s". Typical upwelling values are in the range 0.2 to 0.5 mm/s [1]. With no vertical motion, the total column ozone in their model is ~2500 DU. Observed global mean total column ozone is around 300 DU [2]. The model appears to need unrealisticaly high stratospheric upwelling to produce realistic ozone values of ~270 DU.
References:
[1] Butchart, N. (2014), The Brewer-Dobson circulation, Rev. Geophys., 52, doi:10.1002/2013RG000448.
[2] Chipperfield, M. P. and Bekki, S.: Opinion: Stratospheric ozone – depletion, recovery and new challenges, Atmos. Chem. Phys., 24, 2783–2802, https://doi.org/10.5194/acp-24-2783-2024, 2024.