Article

Large Losses of Total Ozone in Antarctica Reveal Seasonal ClOx/NOx Interaction

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Recent attempts1,2 to consolidate assessments of the effect of human activities on stratospheric ozone (O3) using one-dimensional models for 30° N have suggested that perturbations of total O3 will remain small for at least the next decade. Results from such models are often accepted by default as global estimates3. The inadequacy of this approach is here made evident by observations that the spring values of total O3 in Antarctica have now fallen considerably. The circulation in the lower stratosphere is apparently unchanged, and possible chemical causes must be considered. We suggest that the very low temperatures which prevail from midwinter until several weeks after the spring equinox make the Antarctic stratosphere uniquely sensitive to growth of inorganic chlorine, ClX, primarily by the effect of this growth on the NO2/NO ratio. This, with the height distribution of UV irradiation peculiar to the polar stratosphere, could account for the O3 losses observed.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... To compare modeled S/N with observations, long-running historical TCO data measured by Dobson spectrometers were acquired for three stations: Oxford (UK), Arosa (Switzerland) and Halley (Antarctica) (Brönnimann, 2022;Brönnimann et al., 2003;Farman et al., 1985). Oxford and Arosa data (spanning 1924-2021 and 1926-2012 respectively) are provided by the World Ozone and Ultraviolet Radiation Data Centre (WOUDC) archive. ...
... In contrast to the Northern Hemisphere, Antarctic springtime TCO depletion emerges in 1975TCO depletion emerges in (1974TCO depletion emerges in -1977 16th-84th percentiles) in refC2 simulations. Observations show that the depletion of the ozone layer above Table 3. Antarctica was underway between 1960 and 1980 (Farman et al., 1985;Langematz et al., 2016). Indeed, the emergence of TCO depletion in the Halley Bay (Antarctica) observational record is visible in 1968 (Figure 2c). ...
... It has long been known that 1980-return dates are an oversimplified and arbitrary approach to assessing the effectiveness of the Montreal Protocol. The de-emergence dates calculated here are in some regions statistically significantly different from 1980-return dates (Figure 3), because 1980 does not accurately reflect the onset of significant stratospheric ozone depletion, especially over Antarctica (Farman et al., 1985;Langematz et al., 2016;Shepherd t al., 2014). Because S/N provides an indication of when TCO is no longer statistically significantly different from local (and global, perhaps) unperturbed values, we argue that approaches like the one sketched here are perhaps more suitable metrics for assessing the impact and effectiveness of the Montreal Protocol. ...
Article
Full-text available
Plain Language Summary The stratospheric ozone layer is expected to recover from the damaging effects of chlorofluorocarbons (CFCs) and other halogen‐containing source gases this century. Ozone recovery is traditionally but somewhat arbitrarily defined as the year when total column ozone (TCO) abundances return to 1980 levels. Here, we use a metric commonly used in the climate change emergence literature—signal‐to‐noise (S/N)—to quantify statistically significant changes in TCO in models and observations relative to a period before CFC‐induced ozone depletion began. The S/N framing ties recovery to unperturbed environmental conditions, rather than to the environment in a specific year. We argue that tying recovery to unperturbed local environmental conditions is at least as reasonable as tying it to the same global date. Our calculations, which account for natural variability, show that 1980 does not reflect the onset of statistically significant ozone loss. Using a return of TCO to 1980 levels underestimates the time of recovery in Antarctica, where losses have been most significant, and overestimates the time to recovery in other regions. We conclude that signal‐to‐noise is a useful metric to assess the return of TCO to its baseline state and evaluate the effectiveness of the Montreal Protocol.
... UV-B exposure also can damage the plant life including the agricultural crops, and aquatic ecosystems. The pollution in the upper atmosphere can destroy ozone to create the ozone holes allowing the harmful UV radiation (mainly UV-B, 280-315 nm) to reach the earth (Cicerone, 1987(Cicerone, , 1994Douglass et al., 2014;Farman et al., 1985;Solomon et al., 1986;Solomon 2019). ...
... Discovery of the Antarctic ozone hole by Farman et al. in 1985 revolutionized the understanding of atmospheric science and it led to the development of successful global environmental policies. In 1995, Paul Crutzen, Mario Molina and F. Sherwood Rowland were awarded Noble Prize for their contribution to understand different aspects of ozone depletion. ...
... Anthropogenic activities may perturb the natural ozone cycle (Chapman cycle) to deplete the ozone layer to threaten the living kingdom on the earth but nature confines such ozone depletion mainly in the Antarctic stratospheric region (Farman et al., 1985;Rowland, 2006;Solomon, 1999Solomon, , 2019 which is practically an inhibited region. These are produced there only in the spring time. ...
Article
Full-text available
Man-made activities can release the ozone depleting substances (ODSs) like chlorofluorocarbons (CFCs) and other halocarbons stable in atmosphere and ultimately, they migrate to the stratosphere where they can destroy the ozone layer through the XOx catalytic cycle (X = Cl, Br). The active forms in this catalytic cycle are X and XO that can be arrested in the inactive forms like XONO2 (halogen nitrate, an additive compound of two odd electron molecules XO and NO2) and HX (produced in the reaction of X with CH4) in the stratosphere to prevent the ozone depletion cycle. The catalytically active forms from these inactive species can be regenerated in the reactions on heterogeneous solid surface like polar stratospheric cloud (specially Type II PSC formed at about −85 °C). Formation of such PSC in the stratosphere is only possible in the supercooled stable Antarctic vortex produced in the prolonged winter. In fact, formation of such PSC in the stratosphere is not possible in the other regions of the earth and not even in the Arctic pole where no stable Arctic vortex is generally formed in the winter. Thus nature confines the ozone depletion reactions mainly in the stratosphere of Antarctica pole which is practically inhabited.
... The importance of UV radiation in influencing global ecosystems has been widely discussed, noting that stratospheric ozone is a key factor in modulating the changes of UV radiation at the Earth's surface. Stratospheric ozone levels began to decline in the late 1970s (Farman et al., 1985), which was mainly related to human use of chlorine-and bromine-containing compounds such as chlorofluorocarbons (CFCs) (Molina and Rowland, 1974;Solomon et al., 1986). This decrease in stratospheric ozone led to an increase in surface UV radiation via the creation of a hole in the ozone layer over the Antarctic (Gurney, 1998;Hegglin and Shepherd, 2009;Tourpali et al., 2009;Bais et al., 2015;Eleftheratos et al., 2020). ...
... This decrease in stratospheric ozone led to an increase in surface UV radiation via the creation of a hole in the ozone layer over the Antarctic (Gurney, 1998;Hegglin and Shepherd, 2009;Tourpali et al., 2009;Bais et al., 2015;Eleftheratos et al., 2020). After the Antarctic ozone hole was detected in the 1980s (Farman et al., 1985;Solomon, 1999), the signing and adherence to the Montreal Protocol (MP) in 1987 successfully reduced emissions of ozone-depleting substances. Following the MP, the stratospheric loading of chlorine/bromine peaked in the late 1990s and has since decreased, meaning that the stratospheric ozone levels were projected to recover, and the related increase in UV radiation at Earth's surface should have been abated. ...
Article
Full-text available
Excessive exposure to ultraviolet (UV) radiation harms humans and ecosystems. The level of surface UV radiation had increased due to declines in stratospheric ozone in the late 1970s in response to emissions of chlorofluorocarbons. Following the implementation of the Montreal Protocol, the stratospheric loading of chlorine/bromine peaked in the late 1990s and then decreased; subsequently, stratospheric ozone and surface UV radiation would be expected to recover and decrease, respectively. Here, we show, based on multiple data sources, that the May–September surface UV radiation in the tropics and Northern Hemisphere mid-latitudes has undergone a statistically significant increasing trend [about 60.0 J m–2 (10 yr)–1 ] at the 2σ level for the period 2010–20, due to the onset of total column ozone (TCO) depletion [about −3.5 DU (10 yr)–1 ]. Further analysis shows that the declines in stratospheric ozone after 2010 could be related to an increase in stratospheric nitrogen oxides due to increasing emissions of the source gas nitrous oxide (N2O).
... In the wake of the realization that chlorofluorocarcon (CFC) compounds were part of the ozone depletion problem and were causing global warming, [1][2][3][4] theoretical and experimental efforts to find environmentally friendly CFC replacements have expanded dramatically. Almost 200 nations adopted the Kigali Amendment to the Montreal Protocol 5 in October 2016, making this subject even more relevant. ...
... A typical example of a radical-molecule reaction of atmospheric interest 45 is the reaction between OVOCs and OH, 9,19,20 where both reactant and product channels exhibit loose complexes that are connected by hydrogen-abstraction transition states (TSs). The reaction profile features three steps: (1) formation of a prereaction complex (PRC) from the isolated OVOC + OH radical, (2) formation of a product complex by hydrogen abstraction from the OVOC, and (3) formation of the separated products (OVOC radical and water) from the product complex (PC): ...
Article
Full-text available
The OH radical is the most powerful atmospheric oxidant, being responsible for the chemical breakdown of many pollutants released into the troposphere, including saturated volatile organic compounds (VOCs). Numerous of...
... Caused by emissions of chlorine and bromine-containing substances, stratospheric ozone has been depleted since the 1970s. In the 1980s, decreasing the total column ozone (TCO) was detected in the middle latitudes of both hemispheres and the Antarctic ozone hole was discovered [2]. Governments around the world created an agreement to limit the production of chlorofluorocarbons (CFCs)-the Montreal Protocol, which came into force in 1989. ...
Preprint
Full-text available
Several chemistry-climate models (CCM) underestimate the total column ozone (TCO) over the polar region in the Southern Hemisphere during wintertime. To evaluate potential causes of the problem, we exploit CCM SOCOLv3 to study the TCO over Antarctica sensitivity to the: (1) photo-dissociation rates of ozone for large solar zenith angles; (2) rates of the stratospheric heterogeneous reactions, and (3) intensity of the meridional flux into the polar regions due to sub-grid scale mixing processes in the model. Comparisons of the model results with the satellite-based IASI (Infrared Atmospheric Sounder Interferometer) sensor measurements showed that the most important processes for the improvement of the polar ozone simulation results are photolysis and horizontal mixing. The reasonable tuning of these factors has allowed us to improve the model representation of the ozone annual cycle over the southern polar region. The proposed increase of the horizontal mixing can be recommended for the CCMs with relatively low horizontal resolution.
... In 1985, Farman and coworkers published their observation of a significant springtime depletion in the level of ozone over Halley Bay. 13 In addition, they observed an overall decline in the springtime level of ozone during the years 1982-84. These ground-based measurements were rapidly reinforced by satellite data. ...
Article
Full-text available
Ever since the discovery of the ozone hole over the Antarctic and the recognition of the damaging effects of acid rain, the role of atmospheric aerosol particles in determining the chemical balance of the atmosphere has received much attention. Aerosol particles produced in combustion can also have a deleterious effect on human health. In this article we review the chemistry that can occur on aerosol particles, particularly on aqueous based aerosols in the troposphere. The sources, transformation and loss mechanisms of atmospheric aerosol will be discussed. In particular, we will focus on the role of chemical transformation on aerosol particles in promoting reactions that would otherwise be too slow in the homogeneous atmospheric gas phase. Heterogeneous reaction mechanisms of some key chemical reactions will be described. Recent observations of a high organic content of tropospheric aerosol particles will be described and a model of organic coated aerosols will be reviewed.
... Exposure to methyl chloride can cause a wide variety of issues from frostbite, drowsiness, and dizziness to paralysis, seizures, and coma, depending on the route and level (concentration and duration) of exposure. Methyl chloride is particularly important in the global atmosphere as a major natural source of chlorine to the stratosphere [7], a compound involved in the destruction of the ozone layer [8][9][10][11] (methyl chloride, with concentrations between 500 and 1000 parts per trillion (ppt) [12,13], is the most abundant halocarbon in the Earth's atmosphere, representing 30% of the total chlorine content). The production of methyl chloride is dominated by natural sources, but, to a lesser extent, also by anthropogenic sources, such as agricultural fumigation and/or biomass burning [14]. ...
Article
Full-text available
The effective dipole moment model for molecules of axial C3v symmetry is derived on the basis of the symmetry properties of a molecule which, on the one hand, is of the same order of efficiency (but much simpler and clearer in applications) as the analogous models derived on the basis of the irreducible tensorial sets theory, and, on the other hand, mathematically more correct in comparison with concepts like the Herman-Walles function used in the models. As an application of the general results obtained, we discuss high-resolution infrared spectra of CH335Cl, recorded with the Zürich prototype ZP2001 (Bruker IFS125 HR) Fourier transform infrared spectrometer at a resolution of 0.001 cm-1 and analyzed in the region of 880-1190 cm-1 (ν6 bending fundamental centered at ν0 = 1018.070790 cm-1). Absolute strengths of more than 2800 transitions (2081 lines) were obtained from the fit of their shapes both with Voigt and Hartmann-Tran profiles, and parameters of the effective dipole moment of the ν6 band were determined by the computer code SYMTOMLIST (SYMmetric TOp Molecules: LIne STrengths), created on the basis of a derived theoretical model. As the first step of the analysis of the experimental data, assignments of the recorded lines were made. A total of 5124 transitions with Jmax = 68, Kmax = 21 were assigned to the ν6 band. The weighted fit of 2077 upper energy values obtained from the experimentally recorded transitions was made with a Hamiltonian which takes into account different types of ro-vibrational effects in doubly degenerate vibrational states of the C3v-symmetric molecule. As the result, a set of 25 fitted parameters was obtained which reproduces the initial 2077 upper "experimental" ro-vibrational energy values with a root mean square deviation drms=4.7×10-5 cm-1. At the second step of the analysis, the computer code SYMTOMLIST was used for determination of the parameters of the derived effective dipole moment model. Six effective dipole moment parameters were obtained from the weighted fit procedure which reproduces absolute experimental strengths of the 2804 initial experimental transitions with a relative drms=3.4%.
... Chlorofluorocarbons (CFCs) have been widely used in various applications such as coolants, propellants, and aerosol sprays since the 1930s but have harmful effects on the environment and ozone layer [1][2][3]. Global efforts have sought alternatives, leading to the proposal of hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs). While HFCs do not deplete the ozone layer, they significantly contribute to global warming due to the absorption of C-F bonds [4]. ...
... Estos modelos, sin embargo, estaban equivocados. Las mediciones realizadas en la Antártica mostraban, contra lo esperado, una caída considerable de los niveles (Farman et al., 1985). La capa de ozono se había reducido aproximadamente en 50%. ...
... En 1985 se publica una investigación en la revista Nature, basada en mediciones atmosféricas, en donde se concluye por primera vez que las concentraciones de ozono en la antártica eran muy bajas, y se podía hablar literalmente que existía un agujero en la capa de ozono en esa zona, y que además este agujero tenía relación con la presencia de gases clorados y nitrogenados (Farman, Gardiner & Shanklin, 1985). Esta era la evidencia definitiva que terminaba, al menos a nivel científico, la discusión respecto de la realidad de la destrucción del ozono por parte de los gases CFC y gases nitrogenados, y le daba la razón a Rowland, Molina y Crutzen. ...
Article
El presente artículo narra sobre la vida y obra de uno de los primeros latinoamericanos en ganar el premio Nobel de Química, específicamente por abordar el problema del agujero en la capa de ozono.
... Since stratospheric ozone loss over the Antarctic was first reported in 1985 detailing the thinning of the ozone over past decades, there has been concerns over the effects of increased ultraviolet radiation (UVR) penetration on Earth's ecosystems and its inhabitants (Barnes et al., 2019;Farman et al., 1985). As a shortwave component of sunlight, UVR (100-400 nm) has many important and beneficial functions in ecosystems, for example by sterilising viruses (Abshire, 1987) and stimulating vitamin D production (Adams et al., 1982); however, as a high energy form of electromagnetic radiation, UVR is readily absorbed by biological molecules, (namely nucleic acids and proteins), produces oxygen radicals (namely reactive oxygen species [ROS]) in cells that leads to oxidative damage of lipids, proteins and DNA, and is a genotoxin that may lead to a suite of lethal and sublethal consequences for organisms (Alves & Agustí, 2020;Banaszak & Lesser, 2009;Wurtmann & Wolin, 2009). ...
Article
Ultraviolet radiation (UVR) from the sun is a natural daytime stressor for vertebrates in both terrestrial and aquatic ecosystems. UVR effects on the physiology of vertebrates manifest at the cellular level, but have bottom-up effects at the tissue level and on whole-animal performance and behaviours. Climate change and habitat loss (i.e. loss of shelter from UVR) could interact with and exacerbate the genotoxic and cytotoxic impacts of UVR on vertebrates. Therefore, it is important to understand the range and magnitude of effects that UVR can have on a diversity of physiological metrics, and how these may be shaped by taxa, life stage or geographical range in the major vertebrate groups. Using a meta-analytical approach, we used 895 observations from 47 different vertebrate species (fish, amphibian, reptile and bird), and 51 physiological metrics (i.e. cellular, tissue and whole-animal metrics), across 73 independent studies, to elucidate the general patterns of UVR effects on vertebrate physiology. We found that while UVR's impacts on vertebrates are generally negative, fish and amphibians were the most susceptible taxa, adult and larvae were the most susceptible life stages, and animals inhabiting temperate and tropical latitudes were the most susceptible to UVR stress. This information is critical to further our understanding of the adaptive capacity of vulnerable taxon to UVR stress, and the wide-spread sublethal physiological effects of UVR on vertebrates, such as DNA damage and cellular stress, which may translate up to impaired growth and locomotor performance. These impairments to individual fitness highlighted by our study may potentially cause disruptions at the ecosystem scale, especially if the effects of this pervasive diurnal stressor are exacerbated by climate change and reduced refuge due to habitat loss and degradation. Therefore, conservation of habitats that provide refuge to UVR stress will be critical to mitigate stress from this pervasive daytime stressor.
... From the Japanese Antarctic Meteorological Research Institute, Dr. Shigeru Chubachi measured low ozone levels over Antarctica and discovered depletion in the ozone layer (Ohring, Boykov, Bolle, Hudson and Volkert, 2009). In addition to Chubachi, again in 1984, scientists from the British Antarctic Research determined that the examination in question was repeated every spring and explained that this negative situation was due to human activity (Farman, Gardiner and Shannklin, 1985). ...
... Розподіл загального вмісту озону (ЗВО) над Антар ктикою стає особливо нерівномірним навесні (вере сень-листопад). По перше, з середини 1980 х років у полярній стратосфері південної півкулі щороку, по чинаючи з серпня, утворюється озонова діра [10] область низьких рівнів ЗВО (≤ 220 одиниць Добсона, ОД). На рис. 1 ця область обведена чорним контуром. ...
Article
Full-text available
The data obtained by the authors during the last decade from satellite measurements in 1979–2016 and related to changes in zonal asymmetry of the Antarctic ozone and to their coupling with atmospheric parameters in the Southern Hemisphere are summarized in this work. The spring levels of the Antarctic ozone in 2000s–2010s do not show increase of the ozone hole size observed in 1980s–1990s. Stabilization and the first evidence of the ozone hole area decrease are considered as consequence of Montreal Protocol 1987 on restriction of emissions of ozone depleted substances into the atmosphere. Long3term changes of total ozone content in atmosphere over the Antarctic region in spring are accompanied by changes in its asymmetric distribution relatively the South Pole. Interannual variations of the longitudinal ozone minimum position demonstrate statistically significant relation to structure of the quasi3stationary planetary waves in distribution of atmospheric parameters. Long3term longitudinal shift of the ozone minimum is similar to shift in zonal structure of planetary waves in the tropospheric parameter distribution and is also accompanied by meridional displacement of the climatic anomalies toward the equator. The obtained relationships characterize interdependence between the large3scale tropospheric and stratospheric disturbances in the Southern Hemisphere during the ozone hole season.
... Study of these processes leads to a better understanding of the environments of various mediums [1] and their corresponding cross section data is essential for its quantification. Electron impact cross section data is one of the primary inputs to investigate the chemistry of many environments such as atmospheric science [2], astrophysics [3], radiation science [4] and in various other industrial fields such as plasma etching [5]. Owing to such multifaceted applications, scattering studies have been of great interest to researchers. ...
... Although it did not attract the attention of many policy makers, scientists of various disciplines agreed about the problem and arranged several working groups with the aim of collecting climate data about its variability and effects on the planet. By increasing the amount of scientific data, and with the discovery in 1985 of the decrease in the stratospheric column density over Antarctica (known today as the ozone hole), reported by Farman [6], human attention on the climate crisis began to rapidly increase. ...
Article
Full-text available
In the last century, conventional strategies pursued to reduce or convert CO2 have shown limitations and, consequently, have been pushing the development of innovative routes. Among them, great efforts have been made in the field of heterogeneous electrochemical CO2 conversion, which boasts the use of mild operative conditions, compatibility with renewable energy sources, and high versatility from an industrial point of view. Indeed, since the pioneering studies of Hori and co-workers, a wide range of electrocatalysts have been designed. Starting from the performances achieved using traditional bulk metal electrodes, advanced nanostructured and multi-phase materials are currently being studied with the main goal of overcoming the high overpotentials usually required for the obtainment of reduction products in substantial amounts. This review reports the most relevant examples of metal-based, nanostructured electrocatalysts proposed in the literature during the last 40 years. Moreover, the benchmark materials are identified and the most promising strategies towards the selective conversion to high-added-value chemicals with superior productivities are highlighted.
... ODSs are halogenated organic compounds developed in the last century for industrial use as refrigerants and propellants. Their concentrations in the atmosphere grew rapidly in the decades following World War II, leading to the formation of the ozone hole over Antarctica (18,19), of which the considerable climate impacts over the Southern Hemisphere are now well documented (20,21). In order to protect the ozone layer, the nations of the world met in Montreal in 1987 and negotiated a treaty to regulate and eventually phase-out the production of ODSs. ...
Article
The rapid melting of Arctic sea ice is the largest and clearest signal of anthropogenic climate change. Current projections indicate that the first ice-free Arctic summer will likely occur by mid-century, owing to increasing carbon dioxide concentrations in the atmosphere. However, other powerful greenhouse gases have also contributed to Arctic sea ice loss, notably ozone-depleting substances (ODSs). In the late 1980s, ODSs became strictly regulated by the Montreal Protocol, and their atmospheric concentrations have been declining since the mid-1990s. Here, analyzing new climate model simulations, we demonstrate that the Montreal Protocol, designed to protect the ozone layer, is delaying the first appearance of an ice-free Arctic summer, by up to 15 y, depending on future emissions. We also show that this important climate mitigation stems entirely from the reduced greenhouse gas warming from the regulated ODSs, with the avoided stratospheric ozone losses playing no role. Finally, we estimate that each Gg of averted ODS emissions results in approximately 7 km2 of avoided Arctic sea ice loss.
... However, the benchmark blowing agents for the preparation of PUR foams at the time were chlorofluorocarbons (CFCs) such as trichlorofluoromethane (also known as CFC-11). While the use of bromo-and chlorofluorocarbons as potent blowing agents and refrigerants flourished to reach its peak in the 1980s [1], they were identified [2,3] to be the origin of the degeneration of the stratospheric ozone layer. As a consequence, governments, environmental organizations, and industrials teamed up to initiate a ban of bromo-and chlorofluorocarbons for the widespread use. ...
Article
Full-text available
Despite the long-standing use of per- and polyfluorinated carbons (FCs) as pore size–reducing agents for polyurethane rigid (PUR) foams, their mechanisms of action remain poorly understood. To shed light on these mechanisms, we provide a quantitative analysis of the influence of the FC concentration on the pore size of PUR cup foams of two different model PUR foam systems: an industrially-relevant “technical system” and a simplified “scientific system.” Combining scanning electron microscopy (SEM) and the PORE!SCAN method, we provide a detailed analysis of the pore size distributions of the obtained foams. We confirm that the characteristic pore size of both systems is indeed significantly reduced by adding small quantities of FC. However, we show that there seems to exist a critical FC concentration (about 3 wt.% with respect to the A-component) beyond which adding more FC has a negligible effect. More interestingly, the relative extent of the pore size reduction is almost identical for both PUR foam systems and the normalized pore size distributions remain largely unchanged over the whole range of FC concentrations. Our findings suggest that the FC-driven pore size reduction is a general effect caused by distinct mechanisms that are independent of the choice of the PUR foam system. Moreover, we hypothesize that this effect is not to be searched for during foam aging, as often reported, but during the pre-mixing step.
... márciusi elfogadásakor sem volt ismert a kormányzati delegációk előtt, az említett tudományos közlemény ugyanis 1985. május 16-án látott napvilágot [Farman et al., 1985]. Feltehetően ettől függetlenül 1985. ...
Book
Full-text available
Tibor Faragó, 2023: „Deteriorating and saving our planetary environment”. Academic Publisher (Budapest) 344 p. ISBN 978-963-454-900-0; e-ISBN 978-963-454-857-1 (Main text is in Hungarian; majority of hundreds of quotes are in English.) (Academic Publisher is owned by the Wolters Kluwer and the Hungarian Academy of Sciences) (Title of the book in Hungarian: „Planetáris környezetünk veszélyeztetése és megmentése”) The e-book is on the website of the publisher (available for license holders): https://akademiai.hu/ptudx00416-planetaris-kornyezetunk-veszelyeztetese-es-megmentese.html The author’s version is available from the e-Library of the Hungarian Academy of Sciences: http://real.mtak.hu/161139/ and it is also uploaded to the e-libraries of two universities (ELTE, BCE): https://edit.elte.hu/xmlui/handle/10831/85753/ http://unipub.lib.uni-corvinus.hu/7961/ Abstract Our common planetary home is affected by various hazardous environmental processes resulting from human activities. Such processes became gradually global during the past century and include especially the environmental releases of toxic heavy metals, hazardous chemicals and waste, atmospheric emissions of ozone-depleting substances and greenhouse gases. Their consequences have significant impacts on the living conditions of present and future generations. The author of this book presents the emergence and escalation of these environmental problems, the history of their recognition, the development of the international scientific and political cooperation, their most essential outcomes, including the various multilateral programmes and agreements. Based on the extensive review and analysis of these issues, the main conclusions and lessons are also drawn. (The book includes hundreds of literature references and pertinent quotes from many authors and international documents.) Another book of the author (its printed version) was published about a year ago and it was about the “environmental globalisation”, i.e. on the globalisation process and its general interrelated socio-economic and adverse environmental aspects: Tibor Faragó, 2022: „Our common environment and the globalization” Academic Publisher (Budapest) 216 p. ISBN 978-963-454-765-5 (Main text is in Hungarian; majority of hundreds of quotes are in English.) (Title of the book in Hungarian: „Közös környezetünk és a globalizáció: árnyak és remények”) The e-book is on the website of the publisher (available for license holders): https://akademiai.hu/ptudx00345-kozos-kornyezetunk-es-a-globalizacio.html The author’s version is available from the e-Library of the Hungarian Academy of Sciences: http://real.mtak.hu/133300/ and it is also uploaded to the e-libraries of two universities (ELTE, BCE)
... The ozone not only shields the biosphere from dangerous solar UV radiation but is also essential for the global atmosphere and cli-mate (e.g., Bais et al., 2018;Barnes et al., 2019;Neale et al., 2021). Ozone depletion was registered first using the ground station data (Farman et al., 1985). Afterward, it was confirmed by space observations, which showed that this ozone depletion coined as the Antarctic ozone "hole" can cover the entire Antarctic (Stolarski et al., 1986). ...
Article
Full-text available
It is now recognized and confirmed that the ozone layer shields the biosphere from dangerous solar UV radiation and is also important for the global atmosphere and climate. The observed massive ozone depletion forced the introduction of limitations on the production of halogen-containing ozone-depleting substances (hODSs) by the Montreal Protocol and its amendments and adjustments (MPA). Previous research has demonstrated the success of the Montreal Protocol and increased public awareness of its necessity. In this study, we evaluate the benefits of the Montreal Protocol on climate and ozone evolution using the Earth system model (ESM) SOCOLv4.0 (modeling tools for studies of SOlar Climate Ozone Links) which includes dynamic modules for the ocean, sea ice, interactive ozone, and stratospheric aerosol. Here, we analyze the results of the numerical experiments performed with and without limitations on the ozone-depleting substance (ODS) emissions. In the experiments, we have used CMIP6 (Coupled Model Intercomparison Project) SSP2-4.5 and SSP5-8.5 (Shared Socioeconomic Pathway) scenarios for future forcing behavior. We confirm previous results regarding catastrophic ozone layer depletion and substantial climate warming in the case without MPA limitations. We show that the climate effects of MPA consist of additional global-mean warming by up to 2.5 K in 2100 caused by the direct radiative effect of the hODSs, which is comparable to large climate warming obtained with the SSP5-8.5 scenario. For the first time, we reveal the dramatic effects of MPA on chemical species and cloud cover. The response of surface temperature, precipitation, and sea-ice fields was demonstrated for the first time with the model that has interactive tropospheric and stratospheric chemistry. We have found some differences in the climate response compared to the model with prescribed ozone, which should be further addressed. Our research updates and complements previous modeling studies on the quantifying of MPA benefits for the terrestrial atmosphere and climate.
... In this work, Canadian Brewer data were processed by the Brewer Processing Software (BPS) developed by ECCC (Fioletov and Ogyu, 2008). Here we included one world reference triad (BrT-D; Brewer #145, #187, and #191) and one MLO instrument (Brewer #119). ...
Article
Full-text available
The Brewer ozone spectrophotometer (the Brewer) is one of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW)'s standard ozone-monitoring instruments since the 1980s. The entire global Brewer ozone-monitoring network is operated and maintained via a hierarchical calibration chain, which started from world reference instruments that are independently calibrated via the primary calibration method (PCM) at a premium site (National Oceanic and Atmospheric Administration's (NOAA) Mauna Loa Observatory, Hawaii). These world reference instruments have been maintained by Environment and Climate Change Canada (ECCC) in Toronto for the last 4 decades. Their calibration is transferred to the travelling standard instrument and then to network (field) Brewer instruments at their monitoring sites (all via the calibration transfer method; CTM). Thus, the measurement accuracy for the entire global network is dependent on the calibration of world reference instruments. In 2003, to coordinate regional calibration needs, the Regional Brewer Calibration Center for Europe (RBCC-E) was formed in Izaña, Spain. From that point, RBCC-E began calibrating regional references also via PCM instead of CTM. The equivalency and consistency of world and regional references are then assured during international calibration campaigns. In practice, these two calibration methods have different physical requirements, e.g., the PCM requires a stable ozone field in the short term (i.e., half-day), while the CTM would benefit from larger changes in slant ozone conditions for the calibration periods. This difference dictates that the PCM can only be implemented on Brewer instruments at certain sites and even in certain months of the year. This work is the first effort to use long-term observation records from 11 Brewer instruments at four sites to reveal the challenges in performing the PCM. By utilizing a new calibration simulation model and reanalysis ozone data, this work also quantifies uncertainties in the PCM due to short-term ozone variability. The results are validated by real-world observations and used to provide scientific advice on where and when the PCM can be performed and how many days of observations are needed to achieve the calibration goal (i.e., ensure the calibration uncertainty is within a determined criterion, i.e., ≤5 R6 units; R6 is a measurement-derived double ratio in the actual Brewer processing algorithm). This work also suggests that even if the PCM cannot be used to deliver final calibration results for mid- or high-latitude sites, the statistics of the long-term PCM fitting results can still provide key information for field Brewer instruments as stability indicators (which would provide performance monitoring and data quality assurance).
... As stratospheric ozone is the most important gas affecting the absorption of UV radiation in the atmosphere, preventing as much as 97 %-99 % of incident short-wavelength UV irradiance from reaching the surface (e.g., McKenzie et al., 2007), UV radiation research received the greatest attention after the discovery of the Antarctic ozone hole in 1985 (Chubachi, 1985;Farman et al., 1985). Since then, many efforts have been made to reduce ozone depletion, most notably through the passing of the Montreal Protocol in 1987 and subsequent amendments to this landmark treaty (Velders et al., 2007). ...
Article
Full-text available
This study aims to assess the dependence of spectral UV radiation on different atmospheric and terrestrial factors, including solar zenith angle, ozone, and cloud cover, in the southern polar environment. For this purpose, 23 260 spectra (300–363 nm), obtained by the B199 Mk-III Brewer spectrophotometer at Marambio Base, Antarctic Peninsula region, over the period 2010–2020, were studied. A neural network model was developed to investigate the effects of the explanatory variables at 127 wavelengths in the interval 300–363 nm, with a 0.5 nm sampling interval. Solar zenith angle (SZA) proved to be the most important parameter, followed by cloud cover, total ozone column (TOC), and surface albedo. The relative SZA effect is greatest at the shortest wavelengths, where a 1∘ decrease in SZA results in a 6 %–18 % increase in UV irradiance (305 nm). TOC particularly affects the short wavelengths below approximately 320–325 nm, when for example at 305 nm a 10 DU decrease in TOC causes a 7 %–13 % increase in UV irradiance. The large-scale ozone holes (e.g., in 2011–2012, 2014–2015, 2018–2019) caused the spectral UV irradiance at very short wavelengths to peak in spring, whereas in other seasons (e.g., 2010–2011, 2012–2013), the maxima at all wavelengths were recorded in summer (November to January). Absorption of UV radiance by the ozone also affected the temporal distribution of very high spectral UV irradiances (i.e., highest 10 % of the distribution), when at 305 nm they were observed both in spring and summer months, and at 340 nm they occurred mostly in summer. The effect of cloud cover was strongest near the fully cloudy sky and in the summer months, when the Antarctic clouds tend to be thickest.
... The release into the atmosphere of chlorofluorocarbons (CFCs), which began in the 1930s and reached its peak in the 1990s, came to disturb the balance, both of concentration and distribution, of ozone in the atmosphere, causing the destruction of important amounts of ozone [1] and the appearance of the ozone layer in Antarctica [2]. ...
... Concerns were first raised in the 1970s about the possible impacts of man-made chlorofluorocarbons (CFCs) on stratospheric ozone by Molina and Rowland (1974). These concerns were put into sharp focus by the discovery of the stratospheric ozone hole in the 1980s in Antarctica by Farman et al. (1985). Policy 50 https://doi.org/10.5194/egusphere-2023-426 ...
Preprint
Full-text available
Elevated tropospheric ozone concentrations driven by anthropogenic precursor emissions is an environmental issue scientifically similar to the depletion of the stratospheric ozone layer and global climate change; however, the tropospheric ozone issue lacks the generally accepted, international assessment efforts that have greatly informed our understanding of the other two issues. Here we briefly review those successful science-into-policy approaches, and outline the elements required to conduct a similar process for tropospheric ozone, especially for establishing a simplified model of the underpinning science, useful policy metrics and motivating international policy forums for regulating ozone production over the hemispheric and global scales.
... Stratospheric ozone, which is mainly distributed at an altitude of 20-35 km, can protect Earth's biosphere by absorbing harmful UV radiation [1][2][3][4][5][6]. The Antarctic ozone hole resulting from large ozone loss in the Antarctic spring was discovered by Farman and Stolarski [7,8]. Chlorofluorocarbons (CFCs) derived from anthropogenic emissions have caused a large ozone loss in the Antarctic spring through catalytic cycles at polar stratospheric clouds (PSCs) inside the polar vortex [9,10]. ...
Article
Full-text available
The Environmental Trace Gases Monitoring Instrument 2 (EMI-2), a second-generation Chinese hyperspectral satellite-based spectrometer, was launched on 7 September 2021. The total ozone column (TOC) product, which is one of the most important elements of the EMI-2 mission, is required for monitoring the Antarctic ozone hole and regional tropospheric ozone pollution. The first EMI-2 TOC results using the differential optical absorption spectroscopy (DOAS) method are presented in this study. Significant improvements, such as the fitting interval, reference spectrum, and iterative air mass factor (AMF) calculation scheme, were implemented in the EMI-2 TOC retrieval in comparison with the EMI DOAS TOC algorithm, thus generating more accurate reads. The monthly average EMI-2 DOAS TOCs in November 2021 were compared with the TROPOspheric Monitoring Instrument (TROPOMI) TOCs, and the results showed a good correlation (R = 0.99). The EMI-2 TOCs showed similar global spatial distributions to those of TROPOMI, with an overall mean relative bias and mean standard deviation of 0.16% and 2.38%, respectively. However, large differences (up to 7%) appeared in some polar areas near the coastline, which were mainly caused by different surface albedo algorithms. Furthermore, ground-based measurements from 20 stations across different latitudes derived from the World Ozone and Ultraviolet Radiation Data Center dataset were used to assess the accuracy of the EMI-2 DOAS TOCs, and they had a mean relative bias and mean standard deviation of 0.70% and 3.65%, respectively. These results indicate that the EMI-2 DOAS TOC algorithm can yield reliable global TOCs and monitor daily Antarctic TOCs for assessing the healing of ozone holes.
... Unexpected low total column ozone (TCO 3 ) values observed in the early 1980s over Antarctica alarmed both scientists and public because of anticipated increase of ultraviolet radiation (UVR) reaching the Earth's surface (Chubachi, 1984;Farman et al., 1985;Solomon et al., 1986). Widespread threats of thinning of the stratospheric ozone layer and corresponding danger for the Earth's environment led to signing the Montreal Protocol (MP) in 1987 to phase out the man-made ozone-depleting substances (ODS). ...
Article
Full-text available
We propose a method to examine the current status of the ozone recovery attributed to changes of ozone-depleting substances (ODS) in the stratosphere. The total column ozone (TCO3) datasets used are based on the ground-based (by the Dobson and/or Brewer spectrophotometer) measurements, satellite observations (from the Solar Backscatter Ultraviolet (SBUV) and Ozone Mapping and Profiler Suite (OMPS) instruments), and output of reanalyses (Multi-Sensor Reanalysis version 2 (MSR2) and Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA2)). The TCO3 time series are calculated for selected sites in the mid-latitudes of the Northern Hemisphere (NH, 35–60∘ N), which are station locations with long-term TCO3 observations archived at the World Ozone and Ultraviolet Radiation Data Centre (WOUDC). The TCO3 monthly means (1980–2020) are averaged over the April–September period to obtain TCO3 time series for the warm sub-period of the year. Two types of the averaged TCO3 time series are considered: the original one and non-proxy time series with removed natural variability by a standard multiple regression model. The TCO3 time series were smoothed by the locally weighted scatterplot smoother (LOWESS) and the super smoother (SS). The smoothed TCO3 values in 1980, 1988, 1997, and 2020 were used to build ozone recovery indices (ORIs) in 2020. These are key years in the equivalent effective stratospheric chlorine (EESC) time series for the period 1980–2020, i.e., the stratosphere was only slightly contaminated by ODS in 1980, 1988 is the year in which the EESC value is equal to its value at the end (2020), and in 1997, the EESC maximum was in mid-latitude stratosphere. The first proposed ORI, ORI1, is the normalized difference between the TCO3 values in 2020 and 1988. The second one, ORI2, is the percentage of the recovered TCO3 in 2020 since the ODS maximum. Following these definitions, the corresponding reference ranges (from −0.5 % to 1 % for ORI1 and from 40 % to 60 % for ORI2) are obtained by analyzing a set of possible EESC time series simulated via the Goddard automailer. The ozone recovery phases are classified comparing the current ORI values and their uncertainty ranges (by the bootstrapping) with these reference ranges. In the analyzed TCO3 time series, for specific combinations of datasets, data types, and the smoother used, we find faster (for ORI1 or ORI2 above the reference range) and slower (for ORI1 or ORI2 below the reference range) recovery in 2020 than that inferred from the EESC change, and a continuation of the TCO3 decline after the EESC peak (ORI2<0 %). Strong signal of the slower TCO3 recovery is found in Toronto, Hohenpeissenberg, Hradec Kralove, and Belsk. A continuation of ozone decline after the turnaround in ODS concentration is found in both the original and non-proxy time series from WOUDC (Toronto), SBUV and OMPS (Toronto, Arosa, Hohenpeissenberg, Uccle, Hradec Kralove, and Belsk), and MERRA2 data (Arosa, Hohenpeissenberg, Hradec Kralove, and Belsk).
... These discoveries demonstrated beyond doubt that human activity could affect the stratospheric ozone layer. This became even clearer with the discovery of the Antarctic "ozone hole", a strong depletion of polar stratospheric ozone far larger than anyone had anticipated (Farman et al., 1985). In their seminal work, Solomon et al. (1986) proposed that the localized formation of polar stratospheric clouds (PSCs) at the low temperatures in the Antarctic stratosphere provides additional surfaces for halogen recycling from heterogeneous reactions, which in turn increases ozone depletion. ...
Thesis
Halogen radicals can drastically alter the polar atmospheric chemistry. This is made evident by a recurrent destruction of boundary layer ozone during polar springs called ozone depletion events (ODEs). ODEs are caused by enhanced concentrations of reactive halogens, in particular bromine monoxide (BrO) radicals. Measurements suggest that there are two distinct sets of environmental conditions favoring the emissions of bromine to the atmosphere, namely cold and stable meteorological conditions on one side and less stable conditions associated with low-pressure systems on the other. This thesis investigates the importance of these differing environmental conditions on a pan-Arctic scale by comparing TROPOMI satellite observations of BrO with the results of an meterology model coupled with atmospheric chemistry (WRF-CHEM) for the Arctic spring of 2019. For the retrieval of tropospheric BrO from satellite measurements an algorithm is developed which allows to assess the tropospheric partial column without reliance on external input. Compared to other retrieval algorithms, it enables the full utilization of TROPOMI’s high spatial resolution (7 × 3.5 km²) while also avoiding biases from the use of model data. Satellite observations are used to validate model assumptions. It was demonstrated that a bromine release mechanism from the snow-pack employed in numerous models is unfit to predict ODEs in early February at high solar zenith angles. Case studies demonstrated that the observed spatial patterns and large BrO columns observed during late polar spring in association with polar cyclones can be explained by the intrusion of bromine into the free troposphere. It was shown that the magnitude of bromine emissions from blowing snow in polar cyclones is likely overestimated. A seasonal dependence in the environmental conditions favoring bromine release was established. Calm meteorological conditions favor the occurrence of ODEs during early polar spring. During late March and April, ozone was identified as limiting factor for BrO formation and results indicated high wind speeds as favorable meteorological parameter for bromine release. A statistical analysis of spatial extent and shape of ODEs was conducted, showing a scale of 40 km to 1000 km for bromine enhanced air masses.
... DOI:10.1038/24-9810a0.13 Farman, J. C.,Gardiner, B. G. and Shanklin, J. D. (1985), Large losses of total ozone in Antarctica reveal seasonal Cl0x/NOx interaction, Nature, 315, 207-210. ...
Book
Full-text available
A menudo se destaca que la vida sobre la Tierra es la más preciada diferencia de nuestro planeta respecto al universo entero. El propósito de esta edición es centrar la atención en el papel determinante de la atmósfera, como causa fundamental de diferenciación de la Tierra respecto al resto de los planetas conocidos. Para ello se comienza por describir la naturaleza de los fenómenos naturales y el imprescindible papel de la energía. Luego, desde el punto de vista microscópico se describen algunas de las propiedades macroscópicas de la atmósfera y se abordar cuestiones como ¿Por qué la Tierra tiene atmósfera? ¿Por qué la atmósfera, no se escapa de gravedad de la Tierra? ¿Cuál es el papel de la radiación del Sol? ¿Por qué se da el efecto invernadero? ¿De qué orden de magnitud es la cantidad de agua suspendida en la atmósfera? y ¿Por qué las nubes no se caen encima de nosotros? La Física es la disciplina que permite describir la atmósfera. En esta edición se adaptan elementos y teorías de la Física, como la Teoría de la Radiación y la Teoría Cinética Molecular, para describir su interrelación con la atmósfera. Se presenta la deducción de las funciones de distribución de Maxwell y Maxwell-Boltzmann, y se muestra su utilidad para describir la estratificación de la atmósfera. Con el paso del tiempo, paradójicamente parece estarse abandonando la revisión teórica y se ha vuelto rutinario el adoptar muchas leyes de la Física en forma dogmática, sacrificando el carácter formativo que aporta la elaboración teórica. Por ello y por su interés histórico, varias de las deducciones se han incluido. La sistematización puede facilitar al lector la comprensión y posibilitar su aplicación en deducciones similares.
Preprint
Full-text available
The remote sensing of abundance and properties of HCl - the main atmospheric reservoir of Cl atoms which directly participate in ozone depletion - are important for monitoring the partitioning of chlorine between "ozone-depleting" and "reservoir" species. Such remote studies require knowledge of the shapes of molecular resonances of HCl, which are perturbed by collisions with the molecules of the surrounding air. In this work, we report the first fully quantum calculations of collisional perturbations of the shape of a pure rotational line in H35Cl perturbed by an air-relevant molecule (as the first model system we choose the R(0) line in HCl perturbed by O2). The calculations are performed on our new highly-accurate HCl(X1Σ+)-O2(X3Σ−g) potential energy surface. In addition to pressure broadening and shift, we determine also their speed dependencies and the complex Dicke parameter. This gives important input to the community discussion on the physical meaning of the complex Dicke parameter and its relevance for atmospheric spectra (previously, the complex Dicke parameter for such systems was mainly determined from phenomenological fits to experimental spectra and the physical meaning of its value in that context is questionable). We also calculate the temperature dependence of the line-shape parameters and obtain agreement with the available experimental data. We estimate the total combined uncertainties of our calculations at 2% relative RMSE residuals in the simulated line shape at 296 K. This result constitutes an important step towards computational population of spectroscopic databases with accurate ab initio line-shape parameters for molecular systems of terrestrial atmospheric importance.
Chapter
The beginning of environmental consciousness and policy discussions on environmental protection can be traced back to the nineteenth century. Since the second half of the twentieth century, most policies and action plans towards environmental protection evolved under the leadership of the UN. While the early policies focused on sustainable development, recent policy discussions have moved beyond this, drawing on the idea of ecological resilience. Environmental protection initiatives face several ethical challenges.
Chapter
Ozone is an essential component of the Earth's atmosphere. It is beneficial to life when located in the high atmosphere, but it can be harmful in high concentration at ground level. The dual ozone issues, pollution in the troposphere and depletion of the ozone layer in the stratosphere, are different. However, they both are related to the emission of air pollutants from industry and other human activities.
Preprint
Full-text available
Paul J. Crutzen was a pioneer in atmospheric sciences. At the same time, he was a kind-hearted, humorous person with empathy for the private lives of his colleagues and students, but also with the highest scientific standards for himself and for others. He made fundamental scientific contributions to a wide range of scientific topics in all parts of the atmosphere, from the mesosphere to the stratosphere and to the troposphere near the ground. In particular, he was the first to describe the NOx -driven ozone depletion cycle in the stratosphere, he developed the first mechanisms for the chemical formation of ozone in the troposphere, he provided key ideas to explain the “ozone hole”, and he made fundamental discoveries about the effects of biomass burning on the troposphere. Understanding and addressing the causes of man-made air pollution and climate change was the driving motivation for his scientific work. In his work he did not shy away from challenge and provocation. He pioneered the concept now known as “nuclear winter” and initiated the reopening of the debate on geoengineering. He also brought the term “Anthropocene” to the popular debate. In 2000, Paul was among the founders of the journal “Atmospheric Chemistry and Physics”, which was unique at the time in providing public discussion of published preprints, and also what we now call “open access” to published articles. Paul’s work on human impacts on atmosphere and climate has had a profound impact on the environmental policies of many countries for decades. In the future, his work will continue to be a guide for generations of scientists and environmental policy makers to come.
Article
Using observation and reanalysis data, we investigated the effect of the sea surface temperature anomalies associated with ENSO Modoki from September to October on interannual variations in Antarctic stratospheric ozone from October to November. It was found that the planetary wave anomalies generated by ENSO Modoki in the tropical troposphere propagate to the southern mid- and then high-latitude stratosphere. The planetary wave anomalies have a profound impact on the polar vortex, subsequently affecting the interannual variations in Antarctic stratospheric ozone. Further analysis revealed that the responses of the polar vortex and ozone to ENSO Modoki are mainly modulated by the wave-1 and wave-3 components, and the effect of wave 2 is opposite and offset by those of wave 1 and wave 3. The contribution of the residual waves (after removing waves 1, 2, 3, and the remaining waves) are relatively small. Furthermore, we evaluated the performance of CMIP6 models in simulating the impacts of ENSO Modoki on the southern stratospheric polar vortex and ozone. We selected seven models that include stratospheric processes and stratospheric chemical ozone. We found that all are capable of distinguishing between eastern Pacific ENSO and ENSO Modoki events. However, only GISS-E2-1-G and MPI-ESM-1-2-HAM can simulate the patterns of ozone, circulation, and temperature in the Southern Hemisphere in a manner that closely resembles the reanalysis results. Further analysis indicated that these two models can better simulate the propagation of planetary wave activities in the troposphere forced by ENSO Modoki, whereas the other models produce significantly different results to those obtained from observations. Significance Statement This study found a significant connection between ENSO Modoki and the interannual variability of Antarctic stratospheric ozone in austral spring and investigated the underlying physical mechanisms in detail. In addition, the performances of CMIP6 models in simulating the impact of ENSO Modoki on the southern stratospheric polar vortex and ozone were evaluated. This study not only helps to further understand the characteristics of past Antarctic ozone changes but also helps developers improve the performance of models in simulating Antarctic stratospheric changes.
Article
Full-text available
In contrast to the general stratospheric ozone recovery following international agreements, recent observations show an ongoing net ozone depletion in the tropical lower stratosphere (LS). This depletion is thought to be driven by dynamical transport accelerated by global warming, while chemical processes have been considered to be unimportant. Here we use a chemistry–climate model to demonstrate that halogenated ozone-depleting very short-lived substances (VSLS) chemistry may account for around a quarter of the observed tropical LS negative ozone trend in 1998–2018. VSLS sources include both natural and anthropogenic emissions. Future projections show the persistence of the currently unaccounted for contribution of VSLS to ozone loss throughout the twenty-first century in the tropical LS, the only region of the global stratosphere not projecting an ozone recovery by 2100. Our results show the need for mitigation strategies of anthropogenic VSLS emissions to preserve the present and future ozone layer in low latitudes.
Thesis
Full-text available
As pressões de acionistas, reguladores e da sociedade à integração dos aspectos Environmental, Social and Governance (ESG) nas operações das instituições financeiras (IF) se intensificaram nos últimos anos (WEF, 2020), de modo que a busca pela sustentabilidade empresarial tem se tornado prioridade aos bancos e fintechs. Dado este contexto, as IF têm evoluído a gestão de risco operacional (GRO) para que seja uma alavanca à gestão sustentável dos seus negócios (KÖLBEL et al., 2017). A GRO é uma disciplina conhecida das IF brasileiras, uma vez que o Banco Central do Brasil regula sobre a mesma desde 2006 por meio da Resolução Nº 3.380, desta maneira têm buscado fomentar a capacidade da GRO em gerar menor litigiosidade com clientes e colaboradores, garantir maior segurança aos acionistas e criar valor sustentável no longo prazo (BECCHETTI et. al., 2015). Esta pesquisa teve como objetivos mapear e analisar a integração da GRO com os aspectos ESG em instituições financeiras, para isso foi realizada uma revisão sistemática da literatura e um estudo de caso único com observação participante na maior IF privada da América Latina. As contribuições da dissertação, além de sistematizar o referencial teórico sobre o assunto, são: (a) gerar um modelo de análise (framework) de atuação na GRO adaptada aos critérios ESG, (b) disponibilizar um guia de avaliação do nível de maturidade da GRO nas IF e (c) propor um modelo para mensuração da qualidade da GRO (Score de GRO) na perspectiva dos diferentes stakeholders. Os resultados encontrados sugerem a existência de um novo estágio de maturação da GRO, evoluindo os modelos propostos pela Risk Management Association (2000) e por Trapp (2004), bem como validam a utilização da GRO como uma ferramenta para potencializar a sustentabilidade empresarial nas IF atuantes no Brasil.
Article
Mathematical modeling is typically framed as the art of reductionism of scientific knowledge into an arithmetical layout. However, most untrained people get the art of modeling wrong and end up neglecting it because modeling is not simply about writing equations and generating numbers through simulations. Models tell not only about a story; they are spoken to by the circumstances under which they are envisioned. They guide apprentice and experienced modelers to build better models by preventing known pitfalls and invalid assumptions in the virtual world and, most importantly, learn from them through simulation and identify gaps in pushing scientific knowledge further. The power of the human mind is well-documented for idealizing concepts and creating virtual reality models, and as our hypotheses grow more complicated and more complex data become available, modeling earns more noticeable footing in biological sciences. The fundamental modeling paradigms include discrete-events, dynamic systems, agent-based (AB), and system dynamics (SD). The source of knowledge is the most critical step in the model-building process regardless of the paradigm, and the necessary expertise includes (a) clear and concise mental concepts acquired through different ways that provide the fundamental structure and expected behaviors of the model and (b) numerical data necessary for statistical analysis, not for building the model. The unreasonable effectiveness of models to grow scientific learning and knowledge in sciences arise because different researchers would model the same problem differently, given their knowledge and experiential background, leading to choosing different variables and model structures. Secondly, different researchers might use different paradigms and even unalike mathematics to resolve the same problem; thus, model needs are intrinsic to their perceived assumptions and structures. Thirdly, models evolve as the scientific community knowledge accumulates and matures over time, hopefully resulting in improved modeling efforts; thus, the perfect model is fictional. Some paradigms are most appropriate for macro, high abstraction with less detailed-oriented scenarios, while others are most suitable for micro, low abstraction with higher detailed-oriented strategies. Modern hybridization aggregating artificial intelligence (AI) to mathematical models can become the next technological wave in modeling. AI can be an integral part of the SD/AB models and, before long, write the model code by itself. Success and failures in model building are more related to the ability of the researcher to interpret the data and understand the underlying principles and mechanisms to formulate the correct relationship among variables rather than profound mathematical knowledge.
Article
Full-text available
Modeling for policy has become an integral part of policy making and technology assessment. This became particularly evident to the general public when, during the COVID-19 pandemic, forecasts of infection dynamics based on computer simulations were used to evaluate and justify policy containment measures. Computer models are also playing an increasing role in technology assessment (TA). Computer simulations are used to explore possible futures related to specific technologies, for example, in the area of energy systems analysis. Artificial intelligence (AI) models are also becoming increasingly important. The results is a mix of methods where computer simulations and machine learning converge, posing particular challenges and opening up new research questions. This Special topic brings together case studies from different fields to explore the current state of computational models in general and AI methods in particular for policy and TA.
Preprint
Full-text available
Solar coronal mass ejections can accelerate charged particles, mostly protons, to high energies, causing Solar Particle Events (SPEs). Such energetic particles can precipitate upon the Earth’s atmosphere, mostly in polar regions because of the geomagnetic shielding. Here, SPE induced chlorine activation due to ion-chemistry can occur and the activated chlorine depletes ozone in the polar middle atmosphere. We use a state of the art 1D stacked-box model called Exoplanetary Terrestrial Ion Chemistry (ExoTIC), of atmospheric ion and neutral composition to investigate such events in the Northern Hemisphere (NH). Measurement data from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Environmental Satellite (ENVISAT) were used to evaluate the model results using the Halloween SPE in late October 2003, a well-known large event, as a test field. Sensitivity tests were carried out for different model settings with a focus on the chlorine species of Hypochlorous acid (HOCl) and Chlorine Nitrate (ClONO2) as well as ozone and odd oxides of nitrogen (NOy). The model studies were carried out in the northern hemisphere for a high latitude of 67.5° N, inside the polar cap. Comparison of the simulated effects against MIPAS observations for the Halloween SPE revealed a rather good temporal and spatial agreement for HOCl, ozone and NOy. For ClONO2, a good spatial agreement was found. The best model setting was the one with full ion-chemistry where oxygen atom in the excited state, O(1D) was set to photo-chemical equilibrium. HOCl and ozone changes are very well reproduced by the model, specially for night-time. HOCl was found to be the main active chlorine species under night-time conditions resulting in an increase of more than 0.2 ppbv. Further, ClONO2 enhancements of 0.2–0.3 ppbv have been observed both during daytime and night-time. In a nutshell, the most appropriate model setting delivers satisfying result, i.e. the model can be considered to be positively validated. Model settings that compared best with MIPAS observations were applied to an extreme solar event in 775 A.D., presumably a once in a 1000 year event. With the model applied to this scenario, assessment can be made what is to be expected at worst for effects of a SPE on the middle atmosphere. Here, a systematic analysis comparing the impact of the Halloween SPE and the extreme event on the Earth’s middle atmosphere is presented. As seen from the model simulations, both events were able to perturb the polar stratosphere and mesosphere, with a high production of NOy and odd oxides of hydrogen (HOx). Longer lasting and stronger stratospheric ozone loss was also seen for the extreme event. Qualitative difference between the two events and a long lasting impact on HOCl and hydrochrolic acid (HCl) for the extreme event was found. Chlorine ion-chemistry contributed to a stratospheric ozone loss of 2.4 % during daytime and 10 % during night-time during the Halloween SPE as seen with time dependent ionisation rates applied to the model. Furthermore, while comparing the two events just for the event day, an ozone loss of 10 % and 20 % was found during the Halloween SPE and the extreme event respectively which was due to the impact of chlorine ion-chemistry.
Article
Full-text available
Balloon-borne ozonesondes launched weekly from South Pole Station (1986–2021) measure high-vertical-resolution profiles of ozone and temperature from the surface to 30–35 km altitude. The launch frequency is increased in late winter before the onset of rapid stratospheric ozone loss in September. Ozone hole metrics show that the yearly total column ozone and 14–21 km partial column ozone minimum values and September loss rate trends have been improving (less severe) since 2001. The 36-year record also shows interannual variability, especially in recent years (2019–2021). Here we show additional details of these 3 years by comparing annual minimum profiles observed on the date when the lowest integrated total column ozone occurs. We also compare the July–December time series of the 14–21 km partial column ozone values to the 36-year median with percentile intervals. The 2019 anomalous vortex breakdown showed stratospheric temperatures began warming in early September followed by reduced ozone loss. The minimum total column ozone of 180 Dobson units (DU) was observed on 24 September. This was followed by two stable and cold polar vortex years during 2020 and 2021 with total column ozone minimums at 104 DU (1 October) and 102 DU (7 October), respectively. These years also showed broad near-zero-ozone (loss saturation) regions within the 14–21 km layer by the end of September which persisted into October. Validation of the ozonesonde observations is conducted through the ongoing comparison of total column ozone measurements with the South Pole ground-based Dobson spectrophotometer. The ozonesondes show a more positive bias of 2 ± 3 % (higher) than the Dobson following a thorough evaluation and homogenization of the long-term ozonesonde record completed in 2018.
Book
Full-text available
当前,联合国后京都气候谈判进展迟缓,但世界各地却涌现出多中心的自主治理试验,并与碳市场机制相结合,推进公益市场化的进程。本书力求通过回顾臭氧保护、二氧化硫市场和碳市场的发展历程以及中美碳市场治理实践,回答“哪些行为体如何推动了气候公共物品的可持续提供”问题。通过案例分析和比较研究,笔者发现:全球公私合作关系(PPPs)是解决全球公益供给不足的新型治理模式,均衡的公私供求关系是公益可持续提供的源泉。
Article
Full-text available
Plain Language Summary Ozone‐depleting substances (ODSs) are chemicals developed in the 1920s and 1930s for use in spray cans, refrigerators and plastic foams. Their commercial use increased rapidly in the 1950s and 1960s, but their phase out is underway since the signing of the Montreal Protocol in the 1987, following the identification of their devastating impact on the stratospheric ozone layer. It is well known that ODSs are powerful greenhouse gases, with the second largest warming effect between 1955 and 2005. However, their relative contribution to past global warming has not been quantified previously using comprehensive climate models. Here we show that ODSs were responsible for roughly a third of late 20th Century global warming, Arctic warming and Arctic sea ice decline. In addition, we find that the impact of ODSs on global temperatures is about 20% larger than expected based on the impacts they have on the radiative balance. The impacts of ODSs peak in the Arctic, while their radiative forcing peaks in the tropics, and thus opposes Arctic warming amplification. These findings enhance our understanding of drivers of past climate change, and highlight the importance of the Montreal Protocol for future climate change mitigation.
Conference Paper
The discovery by Farman et al . (1985) of a large springtime depletion of ozone over Antarctica and its subsequent confirmation as a large scale progressive phenomenon has led to intensive theoretical and experimental investigations in both polar regions to determine the cause and extent of this effect.
Conference Paper
An overview of the Earth Observing System, a long-term mission to measure and interpret global change, is presented. Its configuration and instrument complement for atmospheric observations are examined.
Conference Paper
The discovery by Farman et al. (1985) of a large springtime depletion of ozone over Halley Bay, Antarctica and its subsequent confirmation by satellite observations as a large scale progressive phenomenon led to intensive theoretical and experimental investigation to determine the cause of this potentially dangerous effect. Many of the theoretical approaches centered on modifications of stratospheric chemistry by polar stratospheric clouds. Several experimental expeditions were mounted to Antarctica to make observations to verify or disprove the theories.
Article
Full-text available
We present springtime measurements of column amounts of stratospheric nitrogen dioxide measured by ground based absorption spectroscopy from Scott Base, Antarctica (77.8°S, 166.7°E). There is a rapid build up from <1 × 10 ¹⁵ molecules cm ⁻² at the end of August to about 5 × 10 ¹⁵ molecules cm ⁻² by mid October. The period covered is the transition time between winter night, and summer day; and in general the ‘overnight’ decay of NO 2 is small. The decay is most significant at times when the number of hours of sunlight per day exceeds 12 hours. There are large day to day variations in column amounts which indicate that transport is a significant factor.
Article
Full-text available
An increase in the concentration of inorganic chlorine to levels comparable to that of oxidized reactive nitrogen could cause a significant change in the chemistry of the lower stratosphere leading to a reduction potentially larger than 15% in the column density of ozone. This could occur, for example by the middle of the next century, if emissions of man-made chlorocarbons were to grow at a rate of 3% per year. Ozone could be further depressed by release of industrial bromocarbon.
Article
Trace stratospheric species (parts per billion or less) have negligible effects on ozone (parts per million) unless they interact in catalytic cycles that regenerate the trace species. It is appropriate to regard catalytic cycles, null cycles, and consumptive sequences, rather than the elementary chemical reactions, as the components of ozone photochemistry. A general differential equation for ozone is transformed to an equivalent equation that directly identifies the catalytic cycles and sequences. The novel aspect of this article is the completeness with which this transformation is carried out and used. This method of treating stratospheric photochemistry properly partitions ozone destruction rates among Ox, NOx, HOx, and ClX families of reactions. The features of the methane-smog chemistry are clearly brought out. From the midvalues of published measurements of NO2 and ClO, it appears that NO2, ClO, and O3 are sufficient to destroy ozone as fast as it is formed in the range 23–35 km, and NOx reactions and ClX reactions appear to be roughly equal in importance. There is no need to invoke any new or unknown sink for ozone in this region if the midvalues of measured NO2 and ClO are representative of the global average. It is improbable that the high values observed for NO2 or for ClO are representative of global average values. The magnitude of the contribution of HOx reactions to ozone photochemistry cannot be found by this method because of lack of observations of HOO in the stratosphere. These conclusions depend on the accuracy of the stratospheric observations and certain rate constants. Additional measurements are needed, especially for HOO, NO2, ClO, and HO.
Article
Monthly zonal mean global radiative heating rates have been obtained from the surface to 10 mb for all twelve months. Seasonal profiles of the contribution by each constituent are presented in addition to seasonal profiles of net thermal cooling and total radiative heating. Radiation cools the troposphere almost everywhere primarily due to thermal cooling by water vapor with the cooling a maximum in the tropics. The tropical stratosphere is heated by radiation due principally to thermal and solar heating by ozone. This total radiative heating extends into the stratospheric mid-latitudes but higher exhibit cooling due primarily to thermal cooling by COâ with the warmer hemisphere showing more cooling. Comparison with previous theory in the Northern Hemisphere shows qualitative agreemet although the present study has more resolution because of the better specification of the radiative parameters, in particular, ozone and temperature.
Article
With a reasonably complete and up-to-date photochemical model of the stratosphere, we find that the calculated stratospheric ozone-column response to chlorine injections is highly nonlinear. The model calculations assume that the background inorganic (or odd) chlorine, C1X, is due to CH3CI and CC1, v Additional C1X is added to the stratosphere by varying input fluxes ofCC12F e and CC13F. The sensitivity, AO3/AClX , of the stratospheric 0 3 column to added C1X is relatively small forCIX < 3 ppb orAC1X < 2 ppb; slight ozone increases with CIX are possible over a limited range of CIX if the formation of chlorine nitrate proceeds rapidly. This may have important implications for total ozone-column trend assessment. As C1X increases beyond 3 ppb, the stratospheric O3 column decreases with C1X increasingly rapidly. This marked departure from the linearity calculated in past years is largely due to presently accepted faster rates of reaction of OH with HNO3, HNO,, HOe, and HeO e. If stratospheric C1X increases to about 9 ppb due to continued usage of CCIeF e, CC13F, and CH3CC13, the stratospheric O 3 colttmn depletion is calculated to be 6.7-9.0%. Principal uncertainties in these calculations, including the rate of formation of chlorine nitrate, the products of its photolysis, and the present day mixing ratio of C1X are discussed. Calculated ozone decreases due to increased NeO concentrations are also presented.
Article
Ozone measurements have been made regularly at Argentine Islands and Halley Bay since 1957. A recent critical review of the data revealed inconsistencies in the extra-terrestrial constants adopted for the various spectrophotometers used. These have been resolved and the data recalculated to give consistent series. The variations in total ozone on differing time-scales, and their relation to variations in the temperature of the lower stratosphere, are discussed. A major increase in total ozone occurs in the course of the breakdown of the winter polar stratospheric vortex. It is often preceded by large quasi-periodic fluctuations associated with baroclinic waves in the vortex. The response of the vortex to these waves is discussed and comparisons made with conventional data from lower latitude stations and with satellite data on Southern Hemisphere sudden warmings. Long-term trends in total ozone are shown to be small at both stations. A recent global analysis of ozone trends is noted.
Article
Using a simplified, approximate 'Lagrangian-mean' dynamical formulation, the mean meridional mass circulation of the stratosphere and mesosphere is discussed. Under solstice conditions, it is shown that this Lagrangian-mean circulation may be inferred, as a first approximation, from the Eulerian-mean diabatic heating. Diabatic heating rates for the solstices, originally derived by Murgatroyd and Goody (1958), result in Lagrangian-mean rising motion at the tropical tropopause, subsidence across the extra-tropical tropopause, and a very strong summer-to-winter pole flow in the mesosphere. This circulation is exactly that obtained by Murgatroyd and Singleton (1961) for the solstices. Those authors, however, attempted to identify this circulation as the Eulerian-mean motion, and were later criticized for their neglect of the meridional eddy heat flux in the calculation, which proved to be extremely important in the winter hemisphere. The present study, nevertheless, indicates that Murgatroyd and Singleton's circulation may in fact be representative of actual air parcel motions in the stratosphere and mesosphere.