Ozone Changes Research Articles

Assessing ozone pollution and climate change impacts on winter wheat: flux modeling vs. dose-response modeling.

Assessing ozone pollution and climate change impacts on winter wheat: flux modeling vs. dose-response modeling.

Energy and Clean Air Policies Will Overcome the Adverse Effect of Climate Change and Reduce China's Ozone Pollution in the Future: The Insight From a New Two‐Stage Model

Abstract Near‐surface ozone pollution is one of the biggest challenges for Chinese air quality improvement, whereas its future spatiotemporal evolution and driving factors have not been fully investigated. Here, we developed a two‐stage model combining a machine learning technique (XGBoost) and a chemical transport model (WRF‐CMAQ) to assess the ozone change till 2060 in China under three scenarios with various trajectories of climate change, energy transition, and pollution controls. The new model effectively corrected overestimation and underestimation of ozone levels by WRF‐CMAQ and global climate models, respectively. Anthropogenic efforts will overcome the adverse effect of climate and reduce future ozone concentration especially in eastern China and warm season with greater ozone pollution. From a long‐term perspective, energy structure transition was estimated to play a more important role than end‐of‐pipe emission controls with a former to latter ratio of ozone reduction during 2017–2060 at 2.7. With observational information incorporated, our model was demonstrated to better capture the ozone response to precursor emission change than WRF‐CMAQ and corrected the underestimation of ozone reduction for developed urban areas.

Long-term variability study of total column ozone over Nigeria using multi-sensor reanalysis measurements

This study investigated the long-term changes in the total column ozone (TCO) over Nigeria using measurements retrieved from the ozone (O3) multi-sensor reanalysis (MSR). It assessed the spatial variability of TCO in Dobson Unit (DU), its monthly distribution, and interannual variability, and identified trends at these time scales over three decades (1981–2010) using the Sen’s slope estimator. The results of these analyses reveal that over the study area, the O3 maximum and minimum concentrations are 248 DU and 268 DU, respectively, producing an average range of about 255 DU. During the dry season, TCO values were found to be less than 250 DU across the country but greater than 250 DU during the wet season. Furthermore, the interannual O3 characteristics uncover dynamic oscillating features, which can be attributed to the influence of a combination of many atmospheric processes, e.g., the wind pattern and stratospheric intrusion. The contribution of sunspot number, Southern Oscillation Index, and Quasi Biennial Oscillation (QBO) at 10 hPa and 30 hPa to TCO values across Nigeria was also investigated. QBO at 10 and 30 hPa showed statistically significant correlation values with TCO over the region.

Некоторые особенности циркуляции в свободной атмосфере Южного полушария, влияющие на полеты воздушных судов

A brief overview of the circulation features in the troposphere and lower stratosphere of the Southern Hemisphere is presented. Seasonal and long-term changes in the position and intensity of jet streams are considered. Features of the behavior and structure of the tropopause are described, including the polar night time. The impact of global warming and changes in stratospheric ozone on the circulation variations in the Southern Hemisphere is discussed.

Geostationary Satellites Total Ozone Observations: First Results on Ground‐Based Networks Validation Efforts for TEMPO and GEMS

Abstract The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument, launched in April 2023, is North America's first geostationary air pollution monitoring satellite mission. Together with Asia's Geostationary Environment Monitoring Spectrometer (GEMS) launched in 2020 and Europe's upcoming Sentinel‐4, TEMPO contributes to nearly global coverage provided by geostationary satellite constellation. TEMPO and GEMS offer hourly, high‐resolution data of ozone surpassing the once‐daily observations of instruments like the TROPOspheric Monitoring Instrument (TROPOMI) in temporal resolution. This study presents TEMPO's total ozone data, demonstrating TEMPO's ability to observe sudden changes in ozone and UV index. Furthermore, TEMPO and GEMS measurements are validated using ground‐based monitoring networks (Brewer, Dobson, and Pandora). Results show good agreement but also highlight latitude‐dependent discrepancies between the satellite and ground‐based data sets (−2% to 2% for TEMPO, −1% to −3% for GEMS). Findings are further validated using TROPOMI data and reanalysis models.

Extreme surface solar ultraviolet radiation events reduce maize yields in China

Over recent decades, changes in atmospheric ozone and climate have substantially altered surface solar ultraviolet radiation, but the impacts of these changes on crop yields remain unclear. Here we analyze climate data and maize yields from 1992 to 2018 across China to quantify how extreme ultraviolet radiation events—periods of exceptionally high ultraviolet exposure—affect maize production. We show that maize yields decline by about 0.72% for each 1% increase in these events, especially during critical mid-growing stages, although higher soil moisture can reduce this damage. By the 2030 s, extreme ultraviolet radiation could reduce yields by 1.4% and 2.17%, with losses increasing substantially under moderate dry (by 51%) and severe heat stress (by 124%). These findings underscore the necessity of accounting for changes in ultraviolet radiation to improve the accuracy of yield projections.

Widespread surface ozone reduction triggered by dust storm disturbance on ozone production and destruction chemistry.

Natural dust storms are associated with changes to atmospheric photochemical processes, including changes in surface ozone, a critical global air pollutant. Here, we quantified the change in surface ozone during dust storms for regions in China by using a synthesis of measurements and modeling approaches. Our results showed that notable reductions of the average ozone concentration (2.0 to 12.2 parts per billion by volume) were observed during the 12 dust storm events from 2016 to 2023, relative to predust storm levels. The chemical interactions of dust particles with ozone production processes played crucial roles in explaining approximately 13 to 35% of the observed ozone reduction, alongside the impact of intense meteorological disturbances on transport and formation of ozone. Among these interactions, the uptake of ozone, reactive nitrogen, and hydroperoxyl radical by dust particles could substantially contribute to the ozone suppression. This study highlighted the importance of interactions between severe dust pollution and atmospheric photochemistry.

Assessing anthropogenic contributions and uncovering inter-regional periodic patterns of ground ozone with high-resolution predictions in 2015-2019 across China.

Assessing anthropogenic contributions and uncovering inter-regional periodic patterns of ground ozone with high-resolution predictions in 2015-2019 across China.

Chemically enhanced transboundary ozone pollution suppresses city-level emission control benefits

Abstract Severe ozone pollution persists during summertime in 60 cities in the North China Plain and Fenwei Plain, which requires a fundamental change in the current mitigation strategy. Herein, we investigate how city-level ozone pollution would be affected by self- and collaborative mitigation actions among and beyond the 60 cities, by a modeling analysis of the daily maximum 8 h average ozone for summer (June–July–August). We find that a local uniform 20% cut in anthropogenic emissions would decrease ozone by a mere 2.6% and even worsen ozone over two cities. Due to cross-city ozone transport, the implementation of a range of city-specific emission cuts from 10% to 30% resulted in ozone changes that were essentially the same as those obtained from a uniform 20% cut. By contrast, a 20% emission cut across the entire country would decrease ozone in the 60 cities by 4.5% with no ozone deterioration in any city. Furthermore, owing to the transitioned ozone chemical regime and extended ozone chemical lifetime, the transboundary ozone from outside the two plains would be enhanced by emission reductions in the 60 cities (e.g. an increase by 68% with complete removal of emissions), leading to a significant suppression (about 23%) on the expected benefit. Nationwide collaborative action is essential for more effective city-level ozone mitigation.

An Analysis of Ozone and NO2 Variations during the 2014 Solar Proton Event

Background The stratosphere and lower mesosphere serve as critical interfaces linking solar activity, ionospheric disturbances, and variations in ozone concentrations, nitrogen compounds, and, ultimately, surface weather patterns. Fluctuations in stratospheric ozone, along with alterations in other upper atmospheric constituents, directly influence the stratospheric energy balance. These changes may impact stratospheric circulation dynamics, which can subsequently propagate to affect tropospheric climate and weather. Objective The aim of this study is to analyze in situ measurements of total ozone and NO2 in the upper stratosphere and lower mesosphere of the Southern Hemisphere, conducted within the framework of the Belarusian Antarctic Expedition, during the development of the 2014 solar proton event. Additionally, this work seeks to determine the response of total ozone deviations and changes in ozone vertical profiles during intense planetary ionospheric storms. Methods The study utilized spectroscopic measurements of trace gases in the 320–390 nm wavelength range via the zenith-DOAS method. Ground-based zenith-DOAS measurements were conducted using the MARS-B and PION-UV instruments. To evaluate the polar ozone response to ionospheric disturbances, the epoch superposition method was applied, utilizing the ionospheric planetary index Wp alongside average total ozone values over the Southern Hemisphere polar cap (63°S to 90°S), derived from MERRA-2 NOAA reanalysis data. Results The photochemical decay of NO2 during nighttime was experimentally observed, as evidenced by consistently lower NO2 levels in the morning compared to evening values. Synchronous and independent measurements of the slant columns of NO2 and O3 demonstrated a correlation between the temporal variation in their concentrations and the dynamics of the solar proton event. Conclusion Instrumental measurements of ozone and NO2 at upper stratosphere and lower mesosphere altitudes over Antarctica, conducted using MARS-B and PION-UV, indicate that the photochemical decay of nitrogen dioxide occurs during the night following the solar proton event. Given the absence of ground-level sources of ozone and nitrogen dioxide in Antarctica, these findings pertain specifically to stratospheric NO2 and O3 and support a potential role of electrical processes in stratospheric ozone formation. The study concludes that total ozone levels in the Southern Hemisphere polar cap decrease at the onset of ionospheric storms, followed by an increase once the storm subsides. A possible mechanism is proposed for the transfer of solar energy within the middle atmosphere, highlighting the critical role of ozone in this process.

Environmental consequences of interacting effects of changes in stratospheric ozone, ultraviolet radiation, and climate: UNEP Environmental Effects Assessment Panel, Update 2024

This Assessment Update by the Environmental Effects Assessment Panel (EEAP) of the United Nations Environment Programme (UNEP) addresses the interacting effects of changes in stratospheric ozone, solar ultraviolet (UV) radiation, and climate on the environment and human health. These include new modelling studies that confirm the benefits of the Montreal Protocol in protecting the stratospheric ozone layer and its role in maintaining a stable climate, both at low and high latitudes. We also provide an update on projected levels of solar UV-radiation during the twenty-first century. Potential environmental consequences of climate intervention scenarios are also briefly discussed, illustrating the large uncertainties of, for example, Stratospheric Aerosol Injection (SAI). Modelling studies predict that, although SAI would cool the Earth’s surface, other climate factors would be affected, including stratospheric ozone depletion and precipitation patterns. The contribution to global warming of replacements for ozone-depleting substances (ODS) are assessed. With respect to the breakdown products of chemicals under the purview of the Montreal Protocol, the risks to ecosystem and human health from the formation of trifluoroacetic acid (TFA) as a degradation product of ODS replacements are currently de minimis. UV-radiation and climate change continue to have complex interactive effects on the environment due largely to human activities. UV-radiation, other weathering factors, and microbial action contribute significantly to the breakdown of plastic waste in the environment, and in affecting transport, fate, and toxicity of the plastics in terrestrial and aquatic ecosystems, and the atmosphere. Sustainability demands continue to drive industry innovations to mitigate environmental consequences of the use and disposal of plastic and plastic-containing materials. Terrestrial ecosystems in alpine and polar environments are increasingly being exposed to enhanced UV-radiation due to earlier seasonal snow and ice melt because of climate warming and extended periods of ozone depletion. Solar radiation, including UV-radiation, also contributes to the decomposition of dead plant material, which affects nutrient cycling, carbon storage, emission of greenhouse gases, and soil fertility. In aquatic ecosystems, loss of ice cover is increasing the area of polar oceans exposed to UV-radiation with possible negative effects on phytoplankton productivity. However, modelling studies of Arctic Ocean circulation suggests that phytoplankton are circulating to progressively deeper ocean layers with less UV irradiation. Human health is also modified by climate change and behaviour patterns, resulting in changes in exposure to UV-radiation with harmful or beneficial effects depending on conditions and skin type. For example, incidence of melanoma has been associated with increased air temperature, which affects time spent outdoors and thus exposure to UV-radiation. Overall, implementation of the Montreal Protocol and its Amendments has mitigated the deleterious effects of high levels of UV-radiation and global warming for both environmental and human health.

Reducing Long‐Standing Surface Ozone Overestimation in Earth System Modeling by High‐Resolution Simulation and Dry Deposition Improvement

Abstract The overestimation of surface ozone concentration in low‐resolution global atmospheric chemistry and climate models has been a long‐standing issue. We first update the ozone dry deposition scheme in both high‐ (0.25°) and low‐resolution (1°) Community Earth System Model (CESM) version 1.3 runs, by adding the effects of leaf area index and correcting the sunlit and shaded fractions of stomatal resistances. With this update, 5‐year‐long summer simulations (2015–2019) using the low‐resolution CESM still exhibit substantial ozone overestimation (by 6.0–16.2 ppbv) over the U.S., Europe, eastern China, and ozone pollution hotspots. The ozone dry deposition scheme is further improved by adjusting the leaf cuticle conductance, reducing the mean ozone bias by 19%, and increasing the model resolution further reduces the ozone overestimation by 43%. We elucidate the mechanism by which model grid spacing influences simulated ozone, revealing distinctive pathways in urban versus rural areas. In rural areas, grid spacing mainly affects daytime ozone levels, where additional NOx emissions from nearby urban areas result in an ozone boost and overestimation in low‐resolution simulations. In contrast, over urban areas, daytime ozone overestimation follows a similar mechanism due to the influence of volatile organic compounds from surrounding rural areas. However, nighttime ozone overestimation is closely linked to weakened NO titration owing to the redistribution of urban NOx to rural areas. Additionally, stratosphere‐troposphere exchange may also contribute to reducing ozone bias in high‐resolution simulations, warranting further investigation. This optimized high‐resolution CESM may enhance understanding of ozone formation mechanisms, sources, and changes in a warming climate.

ДИНАМИЧЕСКИЕ ЯВЛЕНИЯ В СТРАТОСФЕРНОМ И МЕЗОСФЕРНОМ ОЗОНЕ ПОЛЯРНОЙ АТМОСФЕРЫ В ФЕВРАЛЕ - МАРТЕ 2023 Г

Приводятся результаты микроволновых наблюдений содержания озона средней атмосферы над Апатитами (67° с.ш., 33° в.д.) в зимний сезон 2022/23 г., который пришелся на период высокой активности Солнца в 25-м цикле. В измерениях был использован мобильный озонометр с рабочей частотой 110,8 ГГц. Прибор имел однополосную шумовую температуру 2500 К, что позволило отслеживать вариации содержания О3 с 15-минутным временным разрешением на высотах средней атмосферы. Получены оценки вертикального профиля содержания озона на высотах 22-60 км. Результаты сопоставлены с бортовыми данными MLS/Aura о высотных профилях содержания озона и температуры. Вариации содержания озона проходили на фоне внезапного стратосферного потепления, которое случилось в середине февраля и сопровождалось экстраординарным ростом общего содержания озона от 240 до 500 е.Д. Приведены пределы изменений содержания озона на высотных уровнях 25, 40 и 60 км. Обсуждается влияние интенсивного геомагнитного возмущения (шторма) 23-24 марта на суточный ход содержания озона на высоте 60 км. Результаты исследования вносят вклад в понимание влияния солнечной активности на климат Земли. The results of microwave observations of ozone in the middle atmosphere at Apatity (67° N, 33° E) in winter 2022/2023, during a period of high solar activity in the 25th cycle, are presented. A mobile ozonemeter with an operating frequency of 110.8 GHz was used in the measurements. The device had a single-sideband noise temperature of 2500 K, which made it possible to track variations in O3 with a 15-min resolution in the middle atmosphere. Estimates of the ozone vertical profile at altitudes of 22-60 km have been made. These results were compared with satellite MLS/Aura data on the altitude profiles of ozone and temperature. This report discusses the behavior of ozone in February-March 2023. Ozone variations took place during the sudden stratospheric warming (SSW) which occurred in mid-February and was accompanied by an extraordinary increase in the total ozone content (TOC) from 240 to 500 DU. The limits of ozone changes at altitudes of 25, 40, and 60 km are given. The influence of the intense geomagnetic disturbance (storm) on March 23-24 on the daily variation in ozone at an altitude of 60 km is discussed.

Injecting solid particles into the stratosphere could mitigate global warming but currently entails great uncertainties

Stratospheric aerosol injection could mitigate harmful effects of global warming, but could have undesirable side effects, such as warming the stratosphere and depleting the ozone layer. We explore the potential benefits of solid alumina and calcite particles as alternatives to sulfate aerosols by using an experimentally informed aerosol-chemistry-climate model. Compared to sulfur dioxide, injection of solids reduces stratospheric warming by up to 70% and diffuse radiation by up to 40%, highlighting their potential benefits. Achieving −1 W m−2 of radiative forcing would likely result in very small ozone changes, but sizable uncertainties remain. These arise from poorly understood heterogeneous chemical and microphysical processes, which, under less likely assumptions, could lead to larger global ozone column changes between −14% and +4%. Our work provides recommendations for improving the understanding of stratospheric aerosol injection using materials other than sulfur dioxide, and underscores the need for kinetic laboratory studies.

Phase and Amplitude Relationships Between Ozone, Temperature, and Circulation in the Quasi‐Biennial Oscillation

Abstract The phase and amplitude relationships between dynamical quantities and ozone within the quasi‐biennial oscillation (QBO) are explored. An initial assessment of this is done by applying a principal oscillation pattern analysis to observations (SWOOSH for Ozone) and reanalysis data (ERA5). This analysis highlights features of the ozone and temperature variability including two peaks in amplitude at different heights in the QBO region as well as more subtle phase differences that cannot be explained by a simple QBO theory. We also quantify the sizes of the ozone and temperature advection terms and show that the contribution of background upwelling on variations in the ozone gradient is not negligible . A radiative‐convective equilibrium and photochemical equilibrium model, with the imposed ERA5 QBO variation in upwelling and OSIRIS variations, is used to further understand ozone and temperature changes. The results show that photochemistry and transport are important at all levels, and it is misleading to divide the QBO into separate regimes. Prominent aspects of the variability can be reproduced if ERA5 upwelling is reduced by between 15 and where ERA5 is likely overpredicting the strength of the secondary meridional circulation. Finally, we demonstrate that nonlocality in the vertical plays a major role in QBO dynamics. This arises from ozone transport, the dependence on column ozone of photochemical production, and radiative transfer between layers.

Rossby Wave Breaking and its impact on Tropospheric Ozone Variability over the Indian Subcontinent

Rossby Wave Breaking and its impact on Tropospheric Ozone Variability over the Indian Subcontinent

The short-term comprehensive impact of the phase-out of global coal combustion on air pollution and climate change.

The short-term comprehensive impact of the phase-out of global coal combustion on air pollution and climate change.

Causes of growing middle-to-upper tropospheric ozone over the northwest Pacific region

Abstract. Long-term ozone (O3) changes in the middle-to-upper troposphere are critical to climate radiative forcing and tropospheric O3 pollution. Yet, these changes remain poorly quantified through observations in East Asia. Concerns also persist regarding the data quality of the ozonesondes available at the World Ozone and Ultraviolet Radiation Data Centre (WOUDC) for this region. This study aims to address these gaps by analyzing O3 soundings at four sites along the northwestern Pacific coastal region over the past 3 decades and by assessing their consistency with an atmospheric chemistry–climate model simulation. Utilizing the European Centre for Medium-Range Weather Forecasts (ECMWF) Hamburg (ECHAM)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) nudged simulations, it is demonstrated that trends between model and ozonesonde measurements are overall consistent, thereby gaining confidence in the model's ability to simulate O3 trends and confirming the utility of potentially imperfect observational data. A notable increase in O3 mixing ratio around 0.29–0.82 ppb a−1 extending from the middle troposphere to the upper troposphere is observed in both observations and model simulations between 1990 and 2020, primarily during spring and summer. The timing of these O3 tongues is delayed when moving from south to north along the measurement sites, transitioning from late spring to summer. Investigation into the drivers of these trends using tagged model tracers reveals that O3 of stratospheric origin (O3S) dominates the absolute O3 mixing ratios over the middle-to-upper troposphere in the subtropics, contributing to the observed O3 increases by up to 96 % (40 %) during winter (summer), whereas O3 of tropospheric origin (O3T) governs the absolute value throughout the tropical troposphere and contributes generally much more than 60 % to the positive O3 changes, especially during summer and autumn. During winter and spring, a decrease in O3S is partly counterbalanced by an increase in O3T in the tropical troposphere. This study highlights that the enhanced downward transport of stratospheric O3 into the troposphere in the subtropics and a surge of tropospheric O3 in the tropics are the two key factors driving the enhancement of O3 in the middle-to-upper troposphere along the northwest Pacific region.

Does total column ozone change during a solar eclipse?

Abstract. Several publications have reported that total column ozone (TCO) may oscillate with an amplitude of up to 10 DU (Dobson units) during a solar eclipse, whereas other researchers have not seen evidence that an eclipse leads to variations in TCO beyond the typical natural variability. Here, we try to resolve these contradictions by measuring short-term variations (of seconds to minutes) in TCO using “global” (Sun and sky) and direct-Sun observations in the ultraviolet (UV) range with filter radiometers (GUVis-3511 and Microtops II®). Measurements were performed during three solar eclipses: the “Great American Eclipse” of 2024, which was observed in Mazatlán, Mexico, on 8 April 2024; a partial solar eclipse that took place in the United States on 14 October 2023 and was observed at Fort Collins, Colorado (40.57° N, 105.10° W); and a total solar eclipse that occurred in Antarctica on 4 December 2021 and was observed at Union Glacier (79.76° S, 82.84° W). The upper limits of the amplitude of oscillations in TCO observed at Mazatlán, Fort Collins, and Antarctica were 0.4 %, 0.3 %, and 0.03 %, respectively. The variability at all sites was within that observed during times not affected by an eclipse. The slightly larger variability at Mazatlán is due to cirrus clouds occurring throughout the day of the eclipse and the difficulty of separating changes in the ozone layer from cloud effects. These results support the conclusion that a solar eclipse does not lead to variations in TCO of more than ± 1.2 DU and that these variations are likely much lower, drawing into question reports of much larger oscillations. In addition to calculating TCO, we also present changes in the spectral irradiance and aerosol optical depth during eclipses and compare radiation levels observed during totality. The new results augment our understanding of the effect of a solar eclipse on the Earth's upper atmosphere.

Twenty-first century surface UV radiation changes deduced from CMIP6 models. Part II: effects on UV index and plant growth weighted irradiance.

This paper investigates the evolution of changes in surface ultraviolet (UV) radiation globally, emphasizing the significant impacts of key factors influencing its variability, i.e., total column ozone, aerosols, clouds, and surface reflectivity. Simulations of UV radiation were performed by the UVSPEC radiative transfer model and span from the mid-twentieth century to the end of the twenty-first century. Input data were derived from eleven Earth System Models that participated in the 6th Phase of the Coupled Model Intercomparison Project (CMIP6). The UV Index (UVI) simulations for the late twentieth century indicate an increase in UVI levels relative to the 1950s in the Southern Hemisphere's mid and high latitudes, attributed to ozone depletion, and decreases in southeastern Asia due to increases in aerosols. Projections of changes in UVI for the last decade of the twenty-first century were derived for three Shared Socioeconomic Pathways (SSPs): SSP1-2.6, SSP3-7.0, and SSP5-8.5. Under SSP1-2.6, the scenario with the lowest greenhouse gas (GHG) and aerosol emissions, UVI is projected to increase relative to the 1950s by up to 20% in Europe and North America and to decrease by as much as - 10% over tropical and polar regions. Under SSP3-7.0 and SSP5-8.5, scenarios with higher GHG and aerosol emissions, UVI changes are generally negative globally due to ozone recovery and increases in aerosol optical depth, while localized positive changes are found over Central and South America, Europe, Africa, and the Pacific and Indian Oceans. The changes in the biologically effective solar irradiance for plant growth exhibit similar geographical patterns to UVI with slight differences, due to weaker sensitivity to changes in ozone.