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Sample records for ozone depletion greenhouse

  1. Ozone depletion, greenhouse gases, and climate change

    NASA Technical Reports Server (NTRS)

    Mooney, Harold A.; Baker, D. James, Jr.; Bretherton, Francis P.; Burke, Kevin C.; Clark, William C.; Davis, Margaret B.; Dickinson, Robert E.; Imbrie, John; Malone, Thomas F.; Mcelroy, Michael B.

    1989-01-01

    This symposium was organized to study the unusual convergence of a number of observations, both short and long term that defy an integrated explanation. Of particular importance are surface temperature observations and observations of upper atmospheric temperatures, which have declined significantly in parts of the stratosphere. There has also been a dramatic decline in ozone concentration over Antarctica that was not predicted. Significant changes in precipitation that seem to be latitude dependent have occurred. There has been a threefold increase in methane in the last 100 years; this is a problem because a source does not appear to exist for methane of the right isotopic composition to explain the increase. These and other meteorological global climate changes are examined in detail.

  2. A New Connection Between Greenhouse Warming and Stratospheric Ozone Depletion

    NASA Technical Reports Server (NTRS)

    Salawitch, R.

    1998-01-01

    The direct radiative effects of the build-up of carbon dioxide and other greenhouse gases have led to a gradual cooling of the stratosphere with largest changes in temperature occurring in the upper stratosphere, well above the region of peak ozone concentration.

  3. A New Connection Between Greenhouse Warming and Stratospheric Ozone Depletion

    NASA Technical Reports Server (NTRS)

    Salawitch, R.

    1998-01-01

    The direct radiative effects of the build-up of carbon dioxide and other greenhouse gases have led to a gradual cooling of the stratosphere with largest changes in temperature occurring in the upper stratosphere, well above the region of peak ozone concentration.

  4. Washington Seafood Companies Agree to Cut Ozone-Depleting and Greenhouse Gas Refrigerant Releases

    EPA Pesticide Factsheets

    (Seattle - March 8, 2016) Two seafood processing and cold storage companies, Ocean Gold Seafoods Inc. and Ocean Cold LLC, have agreed to cut their releases of ozone-depleting and greenhouse gases from leaking refrigeration equipment at their facilities in

  5. Spaceship Nigeria: A Topic Study for Global Warming, Greenhouse Effect and Ozone Layer Depletion.

    ERIC Educational Resources Information Center

    Okebukola, Peter; Akpan, Ben B.

    1997-01-01

    Explains the concept of a topic study, how it meets the needs of teachers seeking to integrate their teaching, and how it is especially well suited for environmental education. Outlines curriculum for a topic study on the greenhouse effect and ozone layer depletion. (DDR)

  6. Spaceship Nigeria: A Topic Study for Global Warming, Greenhouse Effect and Ozone Layer Depletion.

    ERIC Educational Resources Information Center

    Okebukola, Peter; Akpan, Ben B.

    1997-01-01

    Explains the concept of a topic study, how it meets the needs of teachers seeking to integrate their teaching, and how it is especially well suited for environmental education. Outlines curriculum for a topic study on the greenhouse effect and ozone layer depletion. (DDR)

  7. Student Teacher Understanding of the Greenhouse Effect, Ozone Layer Depletion, and Acid Rain.

    ERIC Educational Resources Information Center

    Dove, Jane

    1996-01-01

    Describes the results of a survey designed to ascertain details of student teachers' knowledge and misconceptions about the greenhouse effect, acid rain, and ozone layer depletion. Results indicate familiarity with the issues but little understanding of the concepts involved and many commonly held misconceptions. (JRH)

  8. Student Teacher Understanding of the Greenhouse Effect, Ozone Layer Depletion, and Acid Rain.

    ERIC Educational Resources Information Center

    Dove, Jane

    1996-01-01

    Describes the results of a survey designed to ascertain details of student teachers' knowledge and misconceptions about the greenhouse effect, acid rain, and ozone layer depletion. Results indicate familiarity with the issues but little understanding of the concepts involved and many commonly held misconceptions. (JRH)

  9. Nitrous Oxide: A Greenhouse Gas That is Also an Ozone Layer Depleting Gas

    NASA Astrophysics Data System (ADS)

    Ravishankara, A. R.

    2015-12-01

    Nitrous oxide, N2O, is the major source of nitrogen oxides in the stratosphere, where these oxides playa critical roles in ozone layer depletion by itself and moderating ozone layer depletion by chlorinated chemicals. Thus N2O plays a complex role in the stratosphere. Nitrous oxide is also a greenhouse gas and it contributes to the radiative forcing of climate. Indeed, it is considered the third most important greenhouse gas next to carbon dioxide and methane. This dual role of nitrous oxide makes it an interesting gas for the atmosphere- it bridges the issue of ozone layer depletion and climate change. Nitrous oxide has both natural and anthropogenic sources. Therefore, one needs to consider this important distinction between natural and anthropogenic sources as well as its role in two related but separate environmental issues. Further, the sources of nitrous oxide are varied and diffuse, which makes it difficult to quantify different sources. However, it is clear that a majority of anthropogenic nitrous oxide comes from food production (including agricultural and animal growth practices), an activity that is at the heart of human existence. Thus, limiting N2O emissions is not a simple task! I will briefly summarize our understanding of these roles of nitrous oxide in the earth's atmosphere and touch on the possible ways to limit N2O emissions.

  10. Nitrous Oxide: A Greenhouse Gas That is Also an Ozone Layer Depleting Gas

    NASA Astrophysics Data System (ADS)

    Reed, S.; Uriarte, M.; Wood, T. E.; Cavaleri, M. A.; Lugo, A. E.

    2014-12-01

    Nitrous oxide, N2O, is the major source of nitrogen oxides in the stratosphere, where these oxides playa critical roles in ozone layer depletion by itself and moderating ozone layer depletion by chlorinated chemicals. Thus N2O plays a complex role in the stratosphere. Nitrous oxide is also a greenhouse gas and it contributes to the radiative forcing of climate. Indeed, it is considered the third most important greenhouse gas next to carbon dioxide and methane. This dual role of nitrous oxide makes it an interesting gas for the atmosphere- it bridges the issue of ozone layer depletion and climate change. Nitrous oxide has both natural and anthropogenic sources. Therefore, one needs to consider this important distinction between natural and anthropogenic sources as well as its role in two related but separate environmental issues. Further, the sources of nitrous oxide are varied and diffuse, which makes it difficult to quantify different sources. However, it is clear that a majority of anthropogenic nitrous oxide comes from food production (including agricultural and animal growth practices), an activity that is at the heart of human existence. Thus, limiting N2O emissions is not a simple task! I will briefly summarize our understanding of these roles of nitrous oxide in the earth's atmosphere and touch on the possible ways to limit N2O emissions.

  11. Attribution of Ozone Changes in the Near Future: Nonlinear Feedbacks between Ozone Depleting Substances and Greenhouse Gases

    NASA Astrophysics Data System (ADS)

    Meul, Stefanie; Oberländer, Sophie; Langematz, Ulrike

    2014-05-01

    In the first half of the 21st century the stratospheric burden of ozone depleting substances (ODSs) is predicted to decrease due to the regulations in the Montreal Protocol and its amendments. Concomitantly, the concentrations of well-mixed greenhouse gases (GHGs) will continue to rise. As the removal of the ODSs from the stratosphere is also affected by changes in the Brewer-Dobson Circulation, the decrease of halogens will also depend on the rate of the GHG increase. Furthermore, the increasing concentrations of the GHGs methane (CH4) and nitrous oxide (N2O) can modify the halogen-ozone chemistry. Therefore, a non-linear contribution has to be included in the attribution analysis of the ozone changes to ODS and GHG changes. In this study we detect and analyze this non-linear term in a set of appropriately defined timeslice simulations for the year 2045 with the Chemistry-Climate-Model EMAC. The causal processes of the non-linear interactions are studied in more detail by separating the relative ozone changes in the contribution from chemistry (production and loss) and transport. This allows us to identify not only feedbacks between chemistry and temperature but also between chemistry and dynamics, i.e. ozone transport.

  12. Greenhouse gases and ozone depleting compounds in the earth`s atmosphere

    SciTech Connect

    Khalil, M.A.K.

    1996-12-31

    Global warming and ozone depletion are the main environmental problems caused by changes in atmospheric composition. These changes come from human activities that add to the natural cycles of atmospheric gases or put entirely new compounds into the earth`s atmosphere. At present only a few gases play a major role in global climate change and ozone depletion. These are carbon dioxide, methane, nitrous oxide, trichlorofluoromethane (F-11), and dichlorofluoromethane (F-12). There are other gases that also add to these problems but to a lesser extent. This paper is about global warming, ozone depletion and the trends and budgets of the gases that can change the climate or deplete the ozone layer. 8 refs., 3 tabs.

  13. Distinguishing the impacts of ozone-depleting substances and well-mixed greenhouse gases on Arctic stratospheric ozone and temperature trends

    NASA Astrophysics Data System (ADS)

    Rieder, Harald E.; Polvani, Lorenzo M.; Solomon, Susan

    2014-04-01

    Whether stratospheric cooling due to increases in well-mixed greenhouse gases (WMGHG) could increase the depletion of Arctic stratospheric ozone has been the subject of scientific and public attention for decades. Here we provide evidence that changes in the concentrations of ozone-depleting substances (ODS), not WMGHG, have been the primary driver of observed Arctic lower stratospheric trends in both ozone and temperature. We do so by analyzing polar cap ozone and temperature trends in reanalysis data: these clearly suggest that both trends are mainly driven by ODS in the lower stratosphere. This observation-based finding is supported by results from a stratosphere-resolving chemistry-climate model driven with time-varying ODS and WMGHG, specified in isolation and in combination. Taken together, these results provide strong evidence that ODS are the main driver of changes in the Arctic lower stratospheric temperatures and ozone, whereas WMGHG are the primary driver of changes in the upper stratosphere.

  14. OZONE DEPLETION AND THE AIR-SEA EXCHANGE OF GREENHOUSE AND CHEMICALLY REACTIVE TRACE GASES

    EPA Science Inventory

    One of the most important aspects of global change is that of stratospheric ozone depletion and the resulting increase in UV radiation reaching the surface of the Earth. Some 70% of the Earth surface is covered by water containing an extremely complicated milieu of organic and in...

  15. OZONE DEPLETION AND THE AIR-SEA EXCHANGE OF GREENHOUSE AND CHEMICALLY REACTIVE TRACE GASES

    EPA Science Inventory

    One of the most important aspects of global change is that of stratospheric ozone depletion and the resulting increase in UV radiation reaching the surface of the Earth. Some 70% of the Earth surface is covered by water containing an extremely complicated milieu of organic and in...

  16. Potential health effects of greenhouse effect and ozone layer depletion in Australia.

    PubMed

    Ewan, C; Bryant, E A; Calvert, G D; Marthick, J; Condon-Paoloni, D

    1991-04-15

    To identify potential health effects of the greenhouse effect and ozone layer depletion in Australia. Data were derived from a number of sources: (i) published articles accessed from relevant databases in the disciplines of health, public health and climatology over the past 20 years; (ii) published conference proceedings, review monographs and government reports covering the topic; (iii) a survey of experts in public health and climatology/geography (150 individuals were surveyed in the first phase with a 63% response rate); and (iv) a consensus conference in which 22 invited experts reviewed the results of the literature review and survey and a second conference in which 18 senior members of the health bureaucracy and public health profession considered the implications of the findings. Over 200 published articles or monographs were reviewed. Criteria for selection were whether the papers contributed information to the objectives of the review. Because of the nature of the problem under investigation, predictions based on reasonable scientific assumptions were the major content of the review rather than conclusions based on scientific research. The major predicted health effects of long-term climatic change in Australia are skin and eye damage from increased ultraviolet radiation exposure, increased incidence of some respiratory diseases, vector-borne and water-borne diseases, and the social and physical effects of natural hazards and social and economic restructuring. The most vulnerable groups include the aged, the very young, the chronically ill, those living in poorly designed neighbourhoods and those working in outdoor occupations or heavy industry. The potential effects on health of long-term climatic change cover the broad spectrum of public health concerns. Detailed predictions of likely problems in specific geographic areas are not yet possible, but progressive development of such predictive capability is a high priority. Doctors will have an

  17. Stratospheric measurements of ozone-depleting substances and greenhouse gases using AirCores

    NASA Astrophysics Data System (ADS)

    Laube, Johannes; Leedham Elvidge, Emma; Kaiser, Jan; Sturges, Bill; Heikkinen, Pauli; Laurila, Tuomas; Hatakka, Juha; Kivi, Rigel; Chen, Huilin; Fraser, Paul; van der Veen, Carina; Röckmann, Thomas

    2017-04-01

    Retrieving air samples from the stratosphere has previously required aircraft or large balloons, both of which are expensive to operate. The novel "AirCore" technique (Karion et al., 2010) enables stratospheric sampling using weather balloons, which is much more cost effective. AirCores are long (up to 200 m) stainless steel tubes which are placed as a payload on a small balloon, can ascend to over 30 km and fill upon descent, collecting a vertical profile of the atmosphere. Retrieved volumes are much smaller though, which presents a challenge for trace gas analysis. To date, only the more abundant trace gases such as carnon dioxide (CO2) and methane (CH4) have been quantified in AirCores. Halogenated trace gases are also important greenhouse gases and many also deplete stratospheric ozone. Their concentrations are however much lower i.e. typically in the part per trillion (ppt) molar range. We here present the first stratospheric measurements of halocarbons in AirCores obtained using UEA's highly sensitive (detection limits of 0.01-0.1 ppt in 10 ml of air) gas chromatography mass spectrometry system. The analysed air originates from a Stratospheric Air Sub-sampler (Mrozek et al., 2016) which collects AirCore segments after the non-destructive CO2 and CH4 analysis. Successfully measured species include CFC-11, CFC-12, CFC-113, CFC-115, H-1211, H-1301, HCFC-22, HCFC-141b, HCFC-142b, HCFC-133a, and sulphur hexafluoride (SF6). We compare the observed mixing ratios and precisions with data obtained from samples collected during various high-altitude aircraft campaigns between 2009 and 2016 as well as with southern hemisphere tropospheric long-term trends. As part of the ERC-funded EXC3ITE (EXploring stratospheric Composition, Chemistry and Circulation with Innovative Techniques) project more than 40 AirCore flights are planned in the next 3 years with an expanded range of up to 30 gases in order to explore seasonal and interannual variability in the stratosphere

  18. Ozone Depletion by Hydrofluorocarbons

    NASA Astrophysics Data System (ADS)

    Hurwitz, M.; Fleming, E. L.; Newman, P. A.; Li, F.; Mlawer, E. J.; Cady-Pereira, K. E.; Bailey, R.

    2015-12-01

    Hydrofluorocarbons (HFCs) are second-generation replacements for the chlorofluorocarbons (CFCs), halons and other substances that caused the 'ozone hole'. Atmospheric concentrations of HFCs are projected to increase dramatically in the coming decades. Coupled chemistry-climate simulations forced by these projections show that HFCs will impact the global atmosphere in 2050. As strong radiative forcers, HFCs modulate atmospheric temperature, thereby changing ozone-destroying catalytic cycles and enhancing the stratospheric circulation. These changes lead to a weak depletion of stratospheric ozone. Sensitivity simulations with the NASA Goddard Space Flight Center (GSFC) 2D model show that HFC-125 is the most important contributor to atmospheric change in 2050, as compared with HFC-23, HFC-32, HFC-134a and HFC-143a. Incorporating the interactions between chemistry, radiation and dynamics, for a likely 2050 climate, ozone depletion potentials (ODPs) for HFCs range from 4.3x10-4 to 3.5x10-2; previously HFCs were assumed to have negligible ODPs since these species lack chlorine or bromine atoms. The ozone impacts of HFCs are further investigated with the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). The GEOSCCM is a three-dimensional, fully coupled ocean-atmosphere model with interactive stratospheric chemistry. Sensitivity simulations in which CO2, CFC-11 and HCFC-22 are enhanced individually are used as proxies for the atmospheric response to the HFC concentrations expected by the mid-21st century. Sensitivity simulations provide quantitative estimates of the impacts of these greenhouse gases on global total ozone, and can be used to assess their effects on the recovery of Antarctic ozone.

  19. Students' Understanding of the Greenhouse Effect, the Societal Consequences of Reducing CO2 Emissions and the Problem of Ozone Layer Depletion.

    ERIC Educational Resources Information Center

    Andersson, Bjorn; Wallin, Anita

    2000-01-01

    Contributes to the growing body of knowledge about students' conceptions and views of environmental and natural resource issues. Questions 9th and 12th grade Swedish students' understandings of the greenhouse effect, reduction of CO2 emissions, and the depletion of the ozone layer. Observes five models of the greenhouse effect that appear among…

  20. Students' Understanding of the Greenhouse Effect, the Societal Consequences of Reducing CO2 Emissions and the Problem of Ozone Layer Depletion.

    ERIC Educational Resources Information Center

    Andersson, Bjorn; Wallin, Anita

    2000-01-01

    Contributes to the growing body of knowledge about students' conceptions and views of environmental and natural resource issues. Questions 9th and 12th grade Swedish students' understandings of the greenhouse effect, reduction of CO2 emissions, and the depletion of the ozone layer. Observes five models of the greenhouse effect that appear among…

  1. Concept Formation in Environmental Education: 14-Year Olds' Work on the Intensified Greenhouse Effect and the Depletion of the Ozone Layer. Research Report

    ERIC Educational Resources Information Center

    Osterlind, Karolina

    2005-01-01

    A case study is presented describing the work of three pupils in the upper level of compulsory school. The pupils were learning about the intensified greenhouse effect and the depletion of the ozone layer. In their work, the need for certain domain-specific knowledge becomes apparent; for example, understanding such concepts as photosynthesis,…

  2. Concept Formation in Environmental Education: 14-Year Olds' Work on the Intensified Greenhouse Effect and the Depletion of the Ozone Layer. Research Report

    ERIC Educational Resources Information Center

    Osterlind, Karolina

    2005-01-01

    A case study is presented describing the work of three pupils in the upper level of compulsory school. The pupils were learning about the intensified greenhouse effect and the depletion of the ozone layer. In their work, the need for certain domain-specific knowledge becomes apparent; for example, understanding such concepts as photosynthesis,…

  3. A Three-Tier Diagnostic Test to Assess Pre-Service Teachers' Misconceptions about Global Warming, Greenhouse Effect, Ozone Layer Depletion, and Acid Rain

    ERIC Educational Resources Information Center

    Arslan, Harika Ozge; Cigdemoglu, Ceyhan; Moseley, Christine

    2012-01-01

    This study describes the development and validation of a three-tier multiple-choice diagnostic test, the atmosphere-related environmental problems diagnostic test (AREPDiT), to reveal common misconceptions of global warming (GW), greenhouse effect (GE), ozone layer depletion (OLD), and acid rain (AR). The development of a two-tier diagnostic test…

  4. A Three-Tier Diagnostic Test to Assess Pre-Service Teachers' Misconceptions about Global Warming, Greenhouse Effect, Ozone Layer Depletion, and Acid Rain

    ERIC Educational Resources Information Center

    Arslan, Harika Ozge; Cigdemoglu, Ceyhan; Moseley, Christine

    2012-01-01

    This study describes the development and validation of a three-tier multiple-choice diagnostic test, the atmosphere-related environmental problems diagnostic test (AREPDiT), to reveal common misconceptions of global warming (GW), greenhouse effect (GE), ozone layer depletion (OLD), and acid rain (AR). The development of a two-tier diagnostic test…

  5. Addressing Ozone Layer Depletion

    EPA Pesticide Factsheets

    Access information on EPA's efforts to address ozone layer depletion through regulations, collaborations with stakeholders, international treaties, partnerships with the private sector, and enforcement actions under Title VI of the Clean Air Act.

  6. A new interactive chemistry-climate model: 2. Sensitivity of the middle atmosphere to ozone depletion and increase in greenhouse gases and implications for recent stratospheric cooling

    NASA Astrophysics Data System (ADS)

    Manzini, E.; Steil, B.; Brühl, C.; Giorgetta, M. A.; Krüger, K.

    2003-07-01

    The sensitivity of the middle atmosphere circulation to ozone depletion and increase in greenhouse gases is assessed by performing multiyear simulations with a chemistry-climate model. Three simulations with fixed boundary conditions have been carried out: one simulation for the near-past (1960) and two simulations for the near-present (1990 and 2000) conditions, including changes in greenhouse gases, in total organic chlorine, and in average sea surface temperatures. Changes in ozone are simulated interactively by the coupled model. It is found that in the stratosphere, ozone decreases, and that in the Antarctic, the ozone hole develops in both the 1990 and the 2000 simulations but not in the 1960 simulation, as observed. The simulated temperature decreases in the stratosphere and mesosphere from the near past to the present, with the largest changes at the stratopause and at the South Pole in the lower stratosphere, in agreement with current knowledge of temperature trends. In the Arctic lower stratosphere, a cooling in March with respect to the 1960 simulation is found only for the 2000 simulation. Wave activity emerging from the troposphere is found to be comparable in the winters of the 1960 and 2000 simulations, suggesting that ozone depletion and greenhouse gases increase contribute to the 2000-1960 March cooling in the Arctic lower stratosphere. These results therefore provide support to the interpretation that the extreme low temperatures observed in March in the last decade can arise from radiative and chemical processes, although other factors cannot be ruled out. The comparison of the 1960 and 2000 simulations shows an increase in downwelling in the mesosphere at the time of cooling in the lower stratosphere (in March in the Arctic; in October in the Antarctic). The mesospheric increase in downwelling can be explained as the response of the gravity waves to the stronger winds associated with the cooling in the lower stratosphere. Planetary waves appear

  7. Stratospheric ozone depletion.

    PubMed

    Rowland, F Sherwood

    2006-05-29

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290-320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime-the 'Antarctic ozone hole'. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules.

  8. Stratospheric ozone depletion

    PubMed Central

    Rowland, F. Sherwood

    2006-01-01

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290–320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime—the ‘Antarctic ozone hole’. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules. PMID:16627294

  9. Depletion in Antarctic Ozone and Associated Climatic Change,

    DTIC Science & Technology

    ANTARCTIC REGIONS, *CLIMATE, *DEPLETION, *OZONE, AGREEMENTS, ATMOSPHERES, ATMOSPHERICS, CARBON, CARBON DIOXIDE, COMPUTATIONS, DIOXIDES, GREENHOUSE ... EFFECT , GREENHOUSES, HIGH LATITUDES, LATITUDE, LOSSES, MEAN, METHANE, MODELS, NETS, NITROUS OXIDE, OBSERVATION, OXIDES, PERTURBATIONS, REGIONS, STEADY

  10. Ozone depletion following future volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Eric Klobas, J.; Wilmouth, David M.; Weisenstein, Debra K.; Anderson, James G.; Salawitch, Ross J.

    2017-07-01

    While explosive volcanic eruptions cause ozone loss in the current atmosphere due to an enhancement in the availability of reactive chlorine following the stratospheric injection of sulfur, future eruptions are expected to increase total column ozone as halogen loading approaches preindustrial levels. The timing of this shift in the impact of major volcanic eruptions on the thickness of the ozone layer is poorly known. Modeling four possible climate futures, we show that scenarios with the smallest increase in greenhouse gas concentrations lead to the greatest risk to ozone from heterogeneous chemical processing following future eruptions. We also show that the presence in the stratosphere of bromine from natural, very short-lived biogenic compounds is critically important for determining whether future eruptions will lead to ozone depletion. If volcanic eruptions inject hydrogen halides into the stratosphere, an effect not considered in current ozone assessments, potentially profound reductions in column ozone would result.

  11. Children's Models of Understanding of Two Major Global Environmental Issues (Ozone Layer and Greenhouse Effect).

    ERIC Educational Resources Information Center

    Boyes, Edward; Stanisstreet, Martin

    1997-01-01

    Aims to quantify the models that 13- and 14 year-old students hold about the causes of the greenhouse effect and ozone layer depletion. Assesses the prevalence of those ideas that link the two phenomena. Twice as many students think that holes in the ozone layer cause the greenhouse effect than think the greenhouse effect causes ozone depletion.…

  12. Children's Models of Understanding of Two Major Global Environmental Issues (Ozone Layer and Greenhouse Effect).

    ERIC Educational Resources Information Center

    Boyes, Edward; Stanisstreet, Martin

    1997-01-01

    Aims to quantify the models that 13- and 14 year-old students hold about the causes of the greenhouse effect and ozone layer depletion. Assesses the prevalence of those ideas that link the two phenomena. Twice as many students think that holes in the ozone layer cause the greenhouse effect than think the greenhouse effect causes ozone depletion.…

  13. United Kingdom Deriving Emissions linked to Climate Change Network: greenhouse gas and ozone depleting substance measurements from a UK network of tall towers

    NASA Astrophysics Data System (ADS)

    Stanley, Kieran; O'Doherty, Simon; Young, Dickon; Grant, Aoife; Manning, Alistair; Simmonds, Peter; Oram, Dave; Sturges, Bill; Derwent, Richard

    2016-04-01

    Real-time, high-frequency measurement networks are essential for investigating the emissions of gases linked with climate change and stratospheric ozone depletion. These networks can be used to verify greenhouse gas (GHG) and ozone depleting substances (ODS) emission inventories for the Kyoto and Montreal Protocols. Providing accurate and reliable country- and region-specific emissions to the atmosphere are critical for reporting to the UN agencies. The United Kingdom Deriving Emissions linked to Climate Change (UK DECC) Network, operating since 2012, is distinguished by its capability to measure at high-frequency, the influence of all of the important species in the Kyoto and Montreal Protocols from the UK, Ireland and Continental Europe. Data obtained from the UK DECC network are also fed into the European Integrated Carbon Observation System (ICOS). This presentation will give an overview of the UK DECC Network, detailing the analytical techniques used to determine the suite of GHGs and ODSs, as well as the calibration strategy used within the network. Interannual results of key GHGs from the network will also be presented.

  14. Policies on global warming and ozone depletion

    SciTech Connect

    Green, B.

    1987-04-01

    The recent discovery of a dramatic seasonal drop in the amount of ozone over Antarctica has catalyzed concern for protection of stratospheric ozone, the layer of gas that shields the entire planet from excess ultraviolet radiation. Conservative scientific models predict about a 5% reduction in the amount of global ozone by the middle of the next century, with large local variations. The predicted global warming from increased emissions of greenhouse gases will also have differing effects on local climate and weather conditions and consequently on agriculture. Although numerous uncertainties are associated with both ozone depletion and a global warming, there is a consensus that world leaders need to address the problems. The US Congress is now beginning to take note of the task. In this article, one representative outlines some perceptions of the problems and the policy options available to Congress.

  15. Issues in Stratospheric Ozone Depletion.

    NASA Astrophysics Data System (ADS)

    Lloyd, Steven Andrew

    Following the announcement of the discovery of the Antarctic ozone hole in 1985 there have arisen a multitude of questions pertaining to the nature and consequences of polar ozone depletion. This thesis addresses several of these specific questions, using both computer models of chemical kinetics and the Earth's radiation field as well as laboratory kinetic experiments. A coupled chemical kinetic-radiative numerical model was developed to assist in the analysis of in situ field measurements of several radical and neutral species in the polar and mid-latitude lower stratosphere. Modeling was used in the analysis of enhanced polar ClO, mid-latitude diurnal variation of ClO, and simultaneous measurements of OH, HO_2, H_2 O and O_3. Most importantly, such modeling was instrumental in establishing the link between the observed ClO and BrO concentrations in the Antarctic polar vortex and the observed rate of ozone depletion. The principal medical concern of stratospheric ozone depletion is that ozone loss will lead to the enhancement of ground-level UV-B radiation. Global ozone climatology (40^circS to 50^ circN latitude) was incorporated into a radiation field model to calculate the biologically accumulated dosage (BAD) of UV-B radiation, integrated over days, months, and years. The slope of the annual BAD as a function of latitude was found to correspond to epidemiological data for non-melanoma skin cancers for 30^circ -50^circN. Various ozone loss scenarios were investigated. It was found that a small ozone loss in the tropics can provide as much additional biologically effective UV-B as a much larger ozone loss at higher latitudes. Also, for ozone depletions of > 5%, the BAD of UV-B increases exponentially with decreasing ozone levels. An important key player in determining whether polar ozone depletion can propagate into the populated mid-latitudes is chlorine nitrate, ClONO_2 . As yet this molecule is only indirectly accounted for in computer models and field

  16. Ozone Depletion from Nearby Supernovae

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil; Laird, Claude M.; Jackman, Charles H.; Cannizzo, John K.; Mattson, Barbara J.; Chen, Wan; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    Estimates made in the 1970's indicated that a supernova occurring within tens of parsecs of Earth could have significant effects on the ozone layer. Since that time improved tools for detailed modeling of atmospheric chemistry have been developed to calculate ozone depletion, and advances have been made also in theoretical modeling of supernovae and of the resultant gamma ray spectra. In addition, one now has better knowledge of the occurrence rate of supernovae in the galaxy, and of the spatial distribution of progenitors to core-collapse supernovae. We report here the results of two-dimensional atmospheric model calculations that take as input the spectral energy distribution of a supernova, adopting various distances from Earth and various latitude impact angles. In separate simulations we calculate the ozone depletion due to both gamma rays and cosmic rays. We find that for the combined ozone depletion from these effects roughly to double the 'biologically active' UV flux received at the surface of the Earth, the supernova must occur at approximately or less than 8 parsecs.

  17. Ozone depletion, paradigms, and politics

    SciTech Connect

    Iman, R.L.

    1993-10-01

    The destruction of the Earth`s protective ozone layer is a prime environmental concern. Industry has responded to this environmental problem by: implementing conservation techniques to reduce the emission of ozone-depleting chemicals (ODCs); using alternative cleaning solvents that have lower ozone depletion potentials (ODPs); developing new, non-ozone-depleting solvents, such as terpenes; and developing low-residue soldering processes. This paper presents an overview of a joint testing program at Sandia and Motorola to evaluate a low-residue (no-clean) soldering process for printed wiring boards (PWBs). Such processes are in widespread use in commercial applications because they eliminate the cleaning operation. The goal of this testing program was to develop a data base that could be used to support changes in the mil-specs. In addition, a joint task force involving industry and the military has been formed to conduct a follow-up evaluation of low-residue processes that encompass the concerns of the tri-services. The goal of the task force is to gain final approval of the low-residue technology for use in military applications.

  18. Halocarbon ozone depletion and global warming potentials

    NASA Technical Reports Server (NTRS)

    Cox, Richard A.; Wuebbles, D.; Atkinson, R.; Connell, Peter S.; Dorn, H. P.; Derudder, A.; Derwent, Richard G.; Fehsenfeld, F. C.; Fisher, D.; Isaksen, Ivar S. A.

    1990-01-01

    Concern over the global environmental consequences of fully halogenated chlorofluorocarbons (CFCs) has created a need to determine the potential impacts of other halogenated organic compounds on stratospheric ozone and climate. The CFCs, which do not contain an H atom, are not oxidized or photolyzed in the troposphere. These compounds are transported into the stratosphere where they decompose and can lead to chlorine catalyzed ozone depletion. The hydrochlorofluorocarbons (HCFCs or HFCs), in particular those proposed as substitutes for CFCs, contain at least one hydrogen atom in the molecule, which confers on these compounds a much greater sensitivity toward oxidation by hydroxyl radicals in the troposphere, resulting in much shorter atmospheric lifetimes than CFCs, and consequently lower potential for depleting ozone. The available information is reviewed which relates to the lifetime of these compounds (HCFCs and HFCs) in the troposphere, and up-to-date assessments are reported of the potential relative effects of CFCs, HCFCs, HFCs, and halons on stratospheric ozone and global climate (through 'greenhouse' global warming).

  19. Children's Models of the Ozone Layer and Ozone Depletion.

    ERIC Educational Resources Information Center

    Christidou, Vasilia; Koulaidis, Vasilis

    1996-01-01

    The views of 40 primary students on ozone and its depletion were recorded through individual, semi-structured interviews. The data analysis resulted in the formation of a limited number of models concerning the distribution and role of ozone in the atmosphere, the depletion process, and the consequences of ozone depletion. Identifies five target…

  20. Children's Models of the Ozone Layer and Ozone Depletion.

    ERIC Educational Resources Information Center

    Christidou, Vasilia; Koulaidis, Vasilis

    1996-01-01

    The views of 40 primary students on ozone and its depletion were recorded through individual, semi-structured interviews. The data analysis resulted in the formation of a limited number of models concerning the distribution and role of ozone in the atmosphere, the depletion process, and the consequences of ozone depletion. Identifies five target…

  1. A Three-Tier Diagnostic Test to Assess Pre-Service Teachers' Misconceptions about Global Warming, Greenhouse Effect, Ozone Layer Depletion, and Acid Rain

    NASA Astrophysics Data System (ADS)

    Ozge Arslan, Harika; Cigdemoglu, Ceyhan; Moseley, Christine

    2012-07-01

    This study describes the development and validation of a three-tier multiple-choice diagnostic test, the atmosphere-related environmental problems diagnostic test (AREPDiT), to reveal common misconceptions of global warming (GW), greenhouse effect (GE), ozone layer depletion (OLD), and acid rain (AR). The development of a two-tier diagnostic test procedure as described by Treagust constitutes the framework for this study. To differentiate a lack of knowledge from a misconception, a certainty response index is added as a third tier to each item. Based on propositional knowledge statements, related literature, and the identified misconceptions gathered initially from 157 pre-service teachers, the AREPDiT was constructed and administered to 256 pre-service teachers. The Cronbach alpha reliability coefficient of the pre-service teachers' scores was estimated to be 0.74. Content and face validations were established by senior experts. A moderate positive correlation between the participants' both-tiers scores and their certainty scores indicated evidence for construct validity. Therefore, the AREPDiT is a reliable and valid instrument not only to identify pre-service teachers' misconceptions about GW, GE, OLD, and AR but also to differentiate these misconceptions from lack of knowledge. The results also reveal that a majority of the respondents demonstrated limited understandings about atmosphere-related environmental problems and held six common misconceptions. Future studies could test the AREPDiT as a tool for assessing the misconceptions held by pre-service teachers from different programs as well as in-service teachers and high school students.

  2. Biomedical consequences of ozone depletion

    NASA Astrophysics Data System (ADS)

    Coohill, Thomas P.

    1994-07-01

    It is widely agreed that a portion of the earth's protective stratospheric ozone layer is being depleted. The major effect of this ozone loss will be an increase in the amount of ultraviolet radiation (UV reaching the biosphere. This increase will be completely contained within the UVB (290nm - 320nm). It is imperative that assessments be made of the effects of this additional UVB on living organisms. This requires a detailed knowledge of the UVB photobiology of these life forms. One analytical technique to aid in the approximations is the construction of UV action spectra for such important biological end-points as human skin cancer, cataracts, immune suppression; plant photosynthesis and crop yields; and aquatic organism responses to UVB, especially the phytoplankton. Combining these action spectra with the known solar spectrum (and estimates for various ozone depletion scenarios) can give rise to a series of effectiveness spectra for these parameters. This manuscript gives a first approximation, rough estimate, for the effectiveness spectra for some of these bioresponses, and a series of crude temporary values for how a 10% ozone loss would affect the above end-points. These are not intended to masquerade as final answers, but rather, to serve as beginning attempts for a process which should be continually refined. It is hoped that these estimates will be of some limited use to agencies, such as government and industry, that have to plan now for changes in human activities that might alter future atmospheric chemistry in a beneficial manner.

  3. Polar stratospheric clouds and ozone depletion

    NASA Technical Reports Server (NTRS)

    Toon, Owen B.; Turco, Richard P.

    1991-01-01

    A review is presented of investigations into the correlation between the depletion of ozone and the formation of polar stratospheric clouds (PSCs). Satellite measurements from Nimbus 7 showed that over the years the depletion from austral spring to austral spring has generally worsened. Approximately 70 percent of the ozone above Antarctica, which equals about 3 percent of the earth's ozone, is lost during September and October. Various hypotheses for ozone depletion are discussed including the theory suggesting that chlorine compounds might be responsible for the ozone hole, whereby chlorine enters the atmosphere as a component of chlorofluorocarbons produced by humans. The three types of PSCs, nitric acid trihydrate, slowly cooling water-ice, and rapidly cooling water-ice clouds act as important components of the Antarctic ozone depletion. It is indicated that destruction of the ozone will be more severe each year for the next few decades, leading to a doubling in area of the Antarctic ozone hole.

  4. Polar stratospheric clouds and ozone depletion

    NASA Technical Reports Server (NTRS)

    Toon, Owen B.; Turco, Richard P.

    1991-01-01

    A review is presented of investigations into the correlation between the depletion of ozone and the formation of polar stratospheric clouds (PSCs). Satellite measurements from Nimbus 7 showed that over the years the depletion from austral spring to austral spring has generally worsened. Approximately 70 percent of the ozone above Antarctica, which equals about 3 percent of the earth's ozone, is lost during September and October. Various hypotheses for ozone depletion are discussed including the theory suggesting that chlorine compounds might be responsible for the ozone hole, whereby chlorine enters the atmosphere as a component of chlorofluorocarbons produced by humans. The three types of PSCs, nitric acid trihydrate, slowly cooling water-ice, and rapidly cooling water-ice clouds act as important components of the Antarctic ozone depletion. It is indicated that destruction of the ozone will be more severe each year for the next few decades, leading to a doubling in area of the Antarctic ozone hole.

  5. The Case of Ozone Depletion

    NASA Technical Reports Server (NTRS)

    Lambright, W. Henry

    2005-01-01

    While the National Aeronautics and Space Administration (NASA) is widely perceived as a space agency, since its inception NASA has had a mission dedicated to the home planet. Initially, this mission involved using space to better observe and predict weather and to enable worldwide communication. Meteorological and communication satellites showed the value of space for earthly endeavors in the 1960s. In 1972, NASA launched Landsat, and the era of earth-resource monitoring began. At the same time, in the late 1960s and early 1970s, the environmental movement swept throughout the United States and most industrialized countries. The first Earth Day event took place in 1970, and the government generally began to pay much more attention to issues of environmental quality. Mitigating pollution became an overriding objective for many agencies. NASA's existing mission to observe planet Earth was augmented in these years and directed more toward environmental quality. In the 1980s, NASA sought to plan and establish a new environmental effort that eventuated in the 1990s with the Earth Observing System (EOS). The Agency was able to make its initial mark via atmospheric monitoring, specifically ozone depletion. An important policy stimulus in many respects, ozone depletion spawned the Montreal Protocol of 1987 (the most significant international environmental treaty then in existence). It also was an issue critical to NASA's history that served as a bridge linking NASA's weather and land-resource satellites to NASA s concern for the global changes affecting the home planet. Significantly, as a global environmental problem, ozone depletion underscored the importance of NASA's ability to observe Earth from space. Moreover, the NASA management team's ability to apply large-scale research efforts and mobilize the talents of other agencies and the private sector illuminated its role as a lead agency capable of crossing organizational boundaries as well as the science-policy divide.

  6. Recovery of the Ozone Layer: The Ozone Depleting Gas Index

    NASA Astrophysics Data System (ADS)

    Hofmann, David J.; Montzka, Stephen A.

    2009-01-01

    The stratospheric ozone layer, through absorption of solar ultraviolet radiation, protects all biological systems on Earth. In response to concerns over the depletion of the global ozone layer, the U.S. Clean Air Act as amended in 1990 mandates that NASA and NOAA monitor stratospheric ozone and ozone-depleting substances. This information is critical for assessing whether the Montreal Protocol on Substances That Deplete the Ozone Layer, an international treaty that entered into force in 1989 to protect the ozone layer, is having its intended effect of mitigating increases in harmful ultraviolet radiation. To provide the information necessary to satisfy this congressional mandate, both NASA and NOAA have instituted and maintained global monitoring programs to keep track of ozone-depleting gases as well as ozone itself. While data collected for the past 30 years have been used extensively in international assessments of ozone layer depletion science, the language of scientists often eludes the average citizen who has a considerable interest in the health of Earth's protective ultraviolet radiation shield. Are the ozone-destroying chemicals declining in the atmosphere? When will these chemicals decline to pre-ozone hole levels so that the Antarctic ozone hole might disappear? Will this timing be different in the stratosphere above midlatitudes?

  7. Impact of greenhouse gases on the Earth's ozone layer

    NASA Astrophysics Data System (ADS)

    Zadorozhny, Alexander

    A numerical 2-D zonally averaged interactive dynamical radiative-photochemical model of the ozonosphere including aerosol physics is used to examine the role of the greenhouse gases CO2 , CH4 , and N2 O in the future long-term changes of the Earth's ozone layer, in particular in its recovery after reduction of anthropogenic discharges of chlorine and bromine compounds into the atmosphere. The model allows calculating self-consistently diabatic circulation, temperature, gaseous composition of the troposphere and stratosphere at latitudes from the South to North Poles, as well as distribution of sulphate aerosol particles and polar stratospheric clouds (PSCs) of types I and II. The scenarios of expected changes of the anthropogenic pollutants for the period from 1980 through 2050 are taken from Climate Change 2001. The processes, which determine the influence of anthropogenic growth of atmospheric abundance of the greenhouse gases on the dynamics of recovery of the Earth's ozone layer, have been studied in details. Expected cooling of the stratosphere caused by increases of greenhouse gases, most importantly CO2 , essentially influences the ozone layer by two ways: through temperature dependencies of the gas phase reaction rates and through enhancement of polar ozone depletion via increased PSC formation. The model calculations show that a weakness in efficiencies of all gas phase catalytic cycles of the ozone destruction due to cooling of the stratosphere is a dominant mechanism of the impact of the greenhouse gases on the ozone layer in Antarctic as well as at the lower latitudes. This mechanism leads to a significant acceleration of the ozone layer recovery here because of the greenhouse gases growth. On the contrary, the mechanism of the impact of the greenhouse gases on the ozone through PSC modification begins to be more effective in Arctic in comparison with the gas phase mechanism in springs after about 2020, which leads to retard the expected recovery of the

  8. Scientific assessment of ozone depletion: 1991

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Over the past few years, there have been highly significant advances in the understanding of the impact of human activities on the Earth's stratospheric ozone layer and the influence of changes in chemical composition of the radiative balance of the climate system. Specifically, since the last international scientific review (1989), there have been five major advances: (1) global ozone decreases; (2) polar ozone; (3) ozone and industrial halocarbons; (4) ozone and climate relations; and (5) ozone depletion potentials (ODP's) and global warming potentials (GWP's). These topics and others are discussed.

  9. Greenhouse gases and recovery of the Earth's ozone layer

    NASA Astrophysics Data System (ADS)

    Dyominov, I. G.; Zadorozhny, A. M.

    A numerical two-dimension zonally average interactive dynamical radiative-photochemical model of the atmosphere is used for investigation the role of the greenhouse gases CO2, CH4, and N2O in the recovery of the Earth's ozone layer after reduction of anthropogenic discharges in the atmosphere of chlorine and bromine compounds. The model allows calculating self-consistently diabatic circulation, temperature, gaseous composition of the troposphere and stratosphere at latitudes from the South to North Poles, as well as distribution of sulphate aerosol particles and polar stratospheric clouds of types I and II. The scenarios of future changes of the greenhouse gases and chlorine and bromine species are taken from Climate Change 1995. The calculations show that expected cooling of the stratosphere caused by the increasing of the greenhouse gases, particularly CO2, enhances the ozone concentration in the stratosphere due to a weakness of the efficiencies of all catalytic cycles of the ozone destruction caused by temperature dependencies of photochemical reactions. The result of this effect is a significant acceleration of the ozone layer recovery after reduction of anthropogenic discharges in the atmosphere of chlorine and bromine species. On the other hand, the cooling of the stratosphere intensifies a formation of the polar stratospheric clouds in the lower stratosphere in the Polar Regions. Heterogeneous reactions on the polar stratospheric clouds, which are the key processes in the destruction of the ozone layer at the high latitudes, lead to more intensive ozone depletion here, which causes a delay of the ozone layer recovery. The calculations show that this effect is weaker than the first one so that the global ozone will recover faster under conditions of continuing anthropogenic growth of the greenhouse gases. The model predicts in this case that the annual average global ozone will reach its undisturbed level of 1980 by about 2040. If the growth of the

  10. Contrasts between Antarctic and Arctic ozone depletion.

    PubMed

    Solomon, Susan; Portmann, Robert W; Thompson, David W J

    2007-01-09

    This work surveys the depth and character of ozone depletion in the Antarctic and Arctic using available long balloon-borne and ground-based records that cover multiple decades from ground-based sites. Such data reveal changes in the range of ozone values including the extremes observed as polar air passes over the stations. Antarctic ozone observations reveal widespread and massive local depletion in the heart of the ozone "hole" region near 18 km, frequently exceeding 90%. Although some ozone losses are apparent in the Arctic during particular years, the depth of the ozone losses in the Arctic are considerably smaller, and their occurrence is far less frequent. Many Antarctic total integrated column ozone observations in spring since approximately the 1980s show values considerably below those ever observed in earlier decades. For the Arctic, there is evidence of some spring season depletion of total ozone at particular stations, but the changes are much less pronounced compared with the range of past data. Thus, the observations demonstrate that the widespread and deep ozone depletion that characterizes the Antarctic ozone hole is a unique feature on the planet.

  11. Ozone depletion and chlorine loading potentials

    NASA Technical Reports Server (NTRS)

    Pyle, John A.; Wuebbles, Donald J.; Solomon, Susan; Zvenigorodsky, Sergei; Connell, Peter; Ko, Malcolm K. W.; Fisher, Donald A.; Stordal, Frode; Weisenstein, Debra

    1991-01-01

    The recognition of the roles of chlorine and bromine compounds in ozone depletion has led to the regulation or their source gases. Some source gases are expected to be more damaging to the ozone layer than others, so that scientific guidance regarding their relative impacts is needed for regulatory purposes. Parameters used for this purpose include the steady-state and time-dependent chlorine loading potential (CLP) and the ozone depletion potential (ODP). Chlorine loading potentials depend upon the estimated value and accuracy of atmospheric lifetimes and are subject to significant (approximately 20-50 percent) uncertainties for many gases. Ozone depletion potentials depend on the same factors, as well as the evaluation of the release of reactive chlorine and bromine from each source gas and corresponding ozone destruction within the stratosphere.

  12. Global Warming: Lessons from Ozone Depletion

    NASA Astrophysics Data System (ADS)

    Hobson, Art

    2010-11-01

    My teaching and textbook have always covered many physics-related social issues, including stratospheric ozone depletion and global warming. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global warming. Thus, as soon as students in my physics literacy course at the University of Arkansas have developed a conceptual understanding of energy and of electromagnetism, including the electromagnetic spectrum, I devote a lecture (and a textbook section) to ozone depletion and another lecture (and section) to global warming. Humankind came together in 1986 and quickly solved, to the extent that humans can solve it, ozone depletion. We could do the same with global warming, but we haven't and as yet there's no sign that we will. The parallel between the ozone and global warming cases, and the difference in outcomes, are striking and instructive.

  13. Global Warming: Lessons from Ozone Depletion

    ERIC Educational Resources Information Center

    Hobson, Art

    2010-01-01

    My teaching and textbook have always covered many physics-related social issues, including stratospheric ozone depletion and global warming. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global warming. Thus, as soon as students in my physics literacy course at the University of…

  14. Global Warming: Lessons from Ozone Depletion

    ERIC Educational Resources Information Center

    Hobson, Art

    2010-01-01

    My teaching and textbook have always covered many physics-related social issues, including stratospheric ozone depletion and global warming. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global warming. Thus, as soon as students in my physics literacy course at the University of…

  15. 48 CFR 52.223-11 - Ozone-Depleting Substances.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Ozone-Depleting Substances....223-11 Ozone-Depleting Substances. As prescribed in 23.804(a), insert the following clause: Ozone-Depleting Substances (MAY 2001) (a) Definition. Ozone-depleting substance, as used in this clause, means...

  16. 48 CFR 52.223-11 - Ozone-Depleting Substances.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 2 2013-10-01 2013-10-01 false Ozone-Depleting Substances....223-11 Ozone-Depleting Substances. As prescribed in 23.804(a), insert the following clause: Ozone-Depleting Substances (MAY 2001) (a) Definition. Ozone-depleting substance, as used in this clause, means...

  17. 48 CFR 52.223-11 - Ozone-Depleting Substances.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 2 2011-10-01 2011-10-01 false Ozone-Depleting Substances....223-11 Ozone-Depleting Substances. As prescribed in 23.804(a), insert the following clause: Ozone-Depleting Substances (MAY 2001) (a) Definition. Ozone-depleting substance, as used in this clause, means...

  18. 48 CFR 52.223-11 - Ozone-Depleting Substances.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 2 2014-10-01 2014-10-01 false Ozone-Depleting Substances....223-11 Ozone-Depleting Substances. As prescribed in 23.804(a), insert the following clause: Ozone-Depleting Substances (MAY 2001) (a) Definition. Ozone-depleting substance, as used in this clause, means...

  19. 48 CFR 52.223-11 - Ozone-Depleting Substances.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Ozone-Depleting Substances....223-11 Ozone-Depleting Substances. As prescribed in 23.804(a), insert the following clause: Ozone-Depleting Substances (MAY 2001) (a) Definition. Ozone-depleting substance, as used in this clause, means...

  20. Increased polar stratospheric ozone losses and delayed eventual recovery owing to increasing greenhouse-gas concentrations

    NASA Astrophysics Data System (ADS)

    Shindell, Drew T.; Rind, David; Lonergan, Patrick

    1998-04-01

    The chemical reactions responsible for stratospheric ozone depletion are extremely sensitive to temperature. Greenhouse gases warm the Earth's surface but cool the stratosphere radiatively and therefore affect ozone depletion. Here we investigate the interplay between projected future emissions of greenhouse gases and levels of ozone-depleting halogen species using a global climate model that incorporates simplified ozone-depletion chemistry. Temperature and wind changes induced by the increasing greenhouse-gas concentrations alter planetary-wave propagation in our model, reducing the frequency of sudden stratospheric warmings in the Northern Hemisphere. This results in a more stable Arctic polar vortex, with significantly colder temperatures in the lower stratosphere and concomitantly increased ozone depletion. Increased concentrations of greenhouse gases might therefore be at least partly responsible for the very large Arctic ozone losses observed in recent winters. Arctic losses reach a maximum in the decade 2010 to 2019 in our model, roughly a decade after the maximum in stratospheric chlorine abundance. The mean losses are about the same as those over the Antarctic during the early 1990s, with geographically localized losses of up to two-thirds of the Arctic ozone column in the worst years. The severity and the duration of the Antarctic ozone hole are also predicted to increase because of greenhouse-gas-induced stratospheric cooling over the coming decades.

  1. Copenhagen delegates advance phaseout of ozone depleters

    SciTech Connect

    Kirschner, E.

    1992-12-09

    As expected, delegates at the United Nations Ozone Layer Conference in Copenhagen sped up ozone depleter phaseouts from the 1987 Montreal Protocol and the 1990 London amendments. The changes bring the worldwide production phaseout of chlorofluorocarbons (CFCs) and other ozone depleters in developed countries in line with U.S. and European plans announced earlier this year. Adjustments to the protocol, which are binding on the signatories, change the phaseout for CFC, carbon tetrachloride, and methyl chloroform production and consumption to January 1, 1996 from 2000. The 75% reduction of 1986 levels from CFCs by January 1, 1994 is a compromise between European pressure for an 85% cut and the US goal of 70%. Halon production is to end January 1, 1994, as anticipated. Developing countries continue to have a 10-year grace period. Friends of the Earth ozone campaign director Liz Cook counters that the phaseout dates were scheduled with concern for the chemical industry, not for the ozone layer.

  2. Correlation between cosmic rays and ozone depletion.

    PubMed

    Lu, Q-B

    2009-03-20

    This Letter reports reliable satellite data in the period of 1980-2007 covering two full 11-yr cosmic ray (CR) cycles, clearly showing the correlation between CRs and ozone depletion, especially the polar ozone loss (hole) over Antarctica. The results provide strong evidence of the physical mechanism that the CR-driven electron-induced reaction of halogenated molecules plays the dominant role in causing the ozone hole. Moreover, this mechanism predicts one of the severest ozone losses in 2008-2009 and probably another large hole around 2019-2020, according to the 11-yr CR cycle.

  3. Ozone depletion and climate change: impacts on UV radiation.

    PubMed

    McKenzie, R L; Aucamp, P J; Bais, A F; Björn, L O; Ilyas, M; Madronich, S

    2011-02-01

    The Montreal Protocol is working, but it will take several decades for ozone to return to 1980 levels. The atmospheric concentrations of ozone depleting substances are decreasing, and ozone column amounts are no longer decreasing. Mid-latitude ozone is expected to return to 1980 levels before mid-century, slightly earlier than predicted previously. However, the recovery rate will be slower at high latitudes. Springtime ozone depletion is expected to continue to occur at polar latitudes, especially in Antarctica, in the next few decades. Because of the success of the Protocol, increases in UV-B radiation have been small outside regions affected by the Antarctic ozone hole, and have been difficult to detect. There is a large variability in UV-B radiation due to factors other than ozone, such as clouds and aerosols. There are few long-term measurements available to confirm the increases that would have occurred as a result of ozone depletion. At mid-latitudes UV-B irradiances are currently only slightly greater than in 1980 (increases less than ~5%), but increases have been substantial at high and polar latitudes where ozone depletion has been larger. Without the Montreal Protocol, peak values of sunburning UV radiation could have been tripled by 2065 at mid-northern latitudes. This would have had serious consequences for the environment and for human health. There are strong interactions between ozone depletion and changes in climate induced by increasing greenhouse gases (GHGs). Ozone depletion affects climate, and climate change affects ozone. The successful implementation of the Montreal Protocol has had a marked effect on climate change. The calculated reduction in radiative forcing due to the phase-out of chlorofluorocarbons (CFCs) far exceeds that from the measures taken under the Kyoto protocol for the reduction of GHGs. Thus the phase-out of CFCs is currently tending to counteract the increases in surface temperature due to increased GHGs. The amount of

  4. 1,2-dichlorohexafluoro-cyclobutane (1,2-c-C4F6Cl2, R-316c) a Potent Ozone Depleting Substance and Greenhouse Gas: Atmospheric Loss Processes, Lifetimes, and Ozone Depletion and Global Warming Potentials for the (E)- and (Z)- Stereoisomers

    NASA Astrophysics Data System (ADS)

    Papadimitriou, V. C.; McGillen, M. R.; Smith, S. C.; Jubb, A. M.; Portmann, R. W.; Hall, B. D.; Fleming, E. L.; Jackman, C. H.; Burkholder, J. B.

    2013-12-01

    1,2-dichlorohexafluoro-cyclobutane (1,2-c-C4F6Cl2, R-316c) is currently used in medical applications, as inhaled non-immobilizer amnesiac, in limited quantities and has recently been considered as a potential chlorofluoro/hydrofluoro-carbon replacement compound. R-316c usage is not restricted under the Montreal Protocol, although, R-316c represents a potent ozone depleting substance and greenhouse gas. In this work, a combination of laboratory studies of infrared absorption spectra, kinetic, and photolysis processes were performed for the (E)- and (Z)- stereoisomers of R-316c to enable an evaluation of their atmospheric lifetimes, ozone depletion (ODPs) and global warming potentials (GWPs). More specifically, O(1D), OH, and O3 reaction rate coefficients, as well as UV absorption spectra, including temperature dependence, and photolysis quantum yields and stable photolysis end-products were determined. The results from these studies will be presented. R-316c lifetimes and ODPs were evaluated using a 2-D atmospheric chemical model. Both isomers of R-316c were shown to be long-lived substances, primarily removed in the stratosphere by UV photolysis, with large ODPs, >0.3. A line-by-line radiative transfer model was used to calculate radiative efficiencies and, thus, GWPs. The GWPs for both isomers are substantial, ~5000 on the 100-year time horizon. In this presentation, we highlight the need for a thorough evaluation of the atmospheric processing of proposed replacement substances prior to usage and their inevitable emission into the atmosphere. The results of such studies enable policy makers to make informed decisions.

  5. Possible ozone depletions following nuclear explosions

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Borucki, W. J.; Turco, R. P.

    1975-01-01

    The degree of depletion of the ozone layer ensuing after delivery of strategic nuclear warheads (5000 and 10,000 Mton) due to production of nitrogen oxides is theoretically assessed. Strong depletions are calculated for 16-km and 26-km altitudes, peaking 1-2 months after detonation and lasting for three years, while a significant depletion at 36 km would peak after one year. Assuming the explosions occur between 30 and 70 deg N, these effects should be much more pronounced in this region than over the Northern Hemisphere as a whole. It is concluded that Hampson's concern on this matter (1974) is well-founded.-

  6. Possible ozone depletions following nuclear explosions

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Borucki, W. J.; Turco, R. P.

    1975-01-01

    The degree of depletion of the ozone layer ensuing after delivery of strategic nuclear warheads (5000 and 10,000 Mton) due to production of nitrogen oxides is theoretically assessed. Strong depletions are calculated for 16-km and 26-km altitudes, peaking 1-2 months after detonation and lasting for three years, while a significant depletion at 36 km would peak after one year. Assuming the explosions occur between 30 and 70 deg N, these effects should be much more pronounced in this region than over the Northern Hemisphere as a whole. It is concluded that Hampson's concern on this matter (1974) is well-founded.-

  7. Arctic Ozone Depletion from UARS MLS Measurements

    NASA Technical Reports Server (NTRS)

    Manney, G. L.

    1995-01-01

    Microwave Limb Sounder (MLS) measurements of ozone during four Arctic winters are compared. The evolution of ozone in the lower stratosphere is related to temperature, chlorine monoxide (also measured by MLS), and the evolution of the polar vortex. Lagrangian transport calculations using winds from the United Kingdom Meteorological Office's Stratosphere-Troposphere Data Assimilation system are used to estimate to what extent the evolution of lower stratospheric ozone is controlled by dynamics. Observations, along with calculations of the expected dynamical behavior, show evidence for chemical ozone depletion throughout most of the Arctic lower stratospheric vortex during the 1992-93 middle and late winter, and during all of the 1994-95 winter that was observed by MLS. Both of these winters were unusually cold and had unusually cold and had unusually strong Arctic polar vortices compared to meteorological data over the past 17 years.

  8. Comment on "Cosmic-ray-driven reaction and greenhouse effect of halogenated molecules: Culprits for atmospheric ozone depletion and global climate change"

    NASA Astrophysics Data System (ADS)

    Müller, Rolf; Grooß, Jens-Uwe

    2014-04-01

    Lu's "cosmic-ray-driven electron-induced reaction (CRE) theory" is based on the assumption that the CRE reaction of halogenated molecules (e.g., chlorofluorocarbons (CFCs), HCl, ClONO2) adsorbed or trapped in polar stratospheric clouds in the winter polar stratosphere is the key step in forming photoactive halogen species that are the cause of the springtime ozone hole. This theory has been extended to a warming theory of halogenated molecules for climate change. In this comment, we discuss the chemical and physical foundations of these theories and the conclusions derived from the theories. First, it is unclear whether the loss rates of halogenated molecules induced by dissociative electron attachment (DEA) observed in the laboratory can also be interpreted as atmospheric loss rates, but even if this were the case, the impact of DEA-induced reactions on polar chlorine activation and ozone loss in the stratosphere is limited. Second, we falsify several conclusions that are reported on the basis of the CRE theory: There is no polar ozone loss in darkness, there is no apparent 11-year periodicity in polar total ozone measurements, the age of air in the polar lower stratosphere is much older than 1-2 years, and the reported detection of a pronounced recovery (by about 20-25%) in Antarctic total ozone measurements by the year 2010 is in error. There are also conclusions about the future development of sea ice and global sea level which are fundamentally flawed because Archimedes' principle is neglected. Many elements of the CRE theory are based solely on correlations between certain datasets which are no substitute for providing physical and chemical mechanisms causing a particular behavior noticeable in observations. In summary, the CRE theory cannot be considered as an independent, alternative mechanism for polar stratospheric ozone loss and the conclusions on recent and future surface temperature and global sea level change do not have a physical basis.

  9. 26 CFR 52.4682-1 - Ozone-depleting chemicals.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 17 2013-04-01 2013-04-01 false Ozone-depleting chemicals. 52.4682-1 Section 52... EXCISE TAXES (CONTINUED) ENVIRONMENTAL TAXES § 52.4682-1 Ozone-depleting chemicals. (a) Overview. This section provides rules relating to the tax imposed on ozone-depleting chemicals (ODCs) under section...

  10. 26 CFR 52.4682-1 - Ozone-depleting chemicals.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 17 2011-04-01 2011-04-01 false Ozone-depleting chemicals. 52.4682-1 Section 52... EXCISE TAXES (CONTINUED) ENVIRONMENTAL TAXES § 52.4682-1 Ozone-depleting chemicals. (a) Overview. This section provides rules relating to the tax imposed on ozone-depleting chemicals (ODCs) under section...

  11. 26 CFR 52.4682-1 - Ozone-depleting chemicals.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 17 2014-04-01 2014-04-01 false Ozone-depleting chemicals. 52.4682-1 Section 52... EXCISE TAXES (CONTINUED) ENVIRONMENTAL TAXES § 52.4682-1 Ozone-depleting chemicals. (a) Overview. This section provides rules relating to the tax imposed on ozone-depleting chemicals (ODCs) under section...

  12. 26 CFR 52.4682-1 - Ozone-depleting chemicals.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 17 2012-04-01 2012-04-01 false Ozone-depleting chemicals. 52.4682-1 Section 52... EXCISE TAXES (CONTINUED) ENVIRONMENTAL TAXES § 52.4682-1 Ozone-depleting chemicals. (a) Overview. This section provides rules relating to the tax imposed on ozone-depleting chemicals (ODCs) under section...

  13. Ozone depletion: implications for the veterinarian.

    PubMed

    Kopecky, K E

    1978-09-15

    Man has inadvertently modified the stratosphere. There is a good possibility that the ozone layer is being depleted by the use of jet aircraft (SST), chlorofluoromethane propellants, and nitrogen fertilizers. Under unpolluted conditions, the production of ozone equals its destruction. By man's intervention, however, the destruction may exceed the production. The potential outcome is increased intensity of solar ultraviolet (280-400 nm) radiation and penetration to the earth's surface of previously absorbed wavelengths below about 280 nm. The increased ultraviolet radiation would increase the likelihood of skin cancer in man and ocular squamous cell carcinoma in cattle. The climate also might be modified, possibly in an undesirable way.

  14. 1,2-Dichlorohexafluoro-Cyclobutane (1,2-c-C4F6Cl2, R-316c) a Potent Ozone Depleting Substance and Greenhouse Gas: Atmospheric Loss Processes, Lifetimes, and Ozone Depletion and Global Warming Potentials for the (E) and (Z) stereoisomers

    NASA Technical Reports Server (NTRS)

    Papadimitriou, Vassileios C.; McGillen, Max R.; Smith, Shona C.; Jubb, Aaron M.; Portmann, Robert W.; Hall, Bradley D.; Fleming, Eric L.; Jackman, Charles H.; Burkholder, James B.

    2013-01-01

    )-R-316c were calculated using the 2-D model to be 0.46 and 0.54, respectively. Infrared absorption spectra for (E)- and (Z)-R-316c were measured at 296 K and used to estimate their radiative efficiencies (REs) and GWPs; 100-year time-horizon GWPs of 4160 and 5400 were obtained for (E)- and (Z)-R-316c, respectively. Both isomers of R-316c are shown in this work to be long-lived ozone depleting substances and potent greenhouse gases.

  15. 1,2-Dichlorohexafluoro-cyclobutane (1,2-c-C4F6Cl2, R-316c) a potent ozone depleting substance and greenhouse gas: atmospheric loss processes, lifetimes, and ozone depletion and global warming potentials for the (E) and (Z) stereoisomers.

    PubMed

    Papadimitriou, Vassileios C; McGillen, Max R; Smith, Shona C; Jubb, Aaron M; Portmann, Robert W; Hall, Bradley D; Fleming, Eric L; Jackman, Charles H; Burkholder, James B

    2013-10-31

    were calculated using the 2-D model to be 0.46 and 0.54, respectively. Infrared absorption spectra for (E)- and (Z)-R-316c were measured at 296 K and used to estimate their radiative efficiencies (REs) and GWPs; 100-year time-horizon GWPs of 4160 and 5400 were obtained for (E)- and (Z)-R-316c, respectively. Both isomers of R-316c are shown in this work to be long-lived ozone depleting substances and potent greenhouse gases.

  16. Ozone Depletion and Biologically Relevant Ultraviolet Radiation.

    NASA Astrophysics Data System (ADS)

    Zeng, Jun

    1995-01-01

    An atmospheric radiative transfer model is used to calculate surface spectral ultraviolet irradiance under cloud-free conditions, and compared with measurements made at Lauder, New Zealand (45^circ{S }, 170^circ{E}) before and after the eruption of Mt. Pinatubo, and including a snow-covered surface. The ratios of diffuse to direct irradiance depend critically on solar elevation, surface albedo, and aerosol extinction. Ozone changes have pronounced effects on the global UVB irradiance, but have only a minor effect on these ratios. The comparison suggests that the ultraviolet radiation exposure can be computed with confidence for clear sky conditions, if the appropriate atmospheric pressure and temperature profiles, ozonesonde data, surface albedo, and aerosol optical properties are available. The total ozone abundances are derived by using ground-based UV irradiance measurements and compared with TOMS in Antarctica and the Arctic from 1990 to 1994. The comparisons show that they are generally in good agreement. Possible reasons for the discrepancies between the two methods are discussed. The equivalent cloud optical depths are also inferred from these data. Ozone depletion can also increase the penetration of ultraviolet radiation into the aquatic system. A coupled atmosphere-ocean radiative transfer model is used to investigate the effect of ozone depletion on UV penetration through the atmosphere and into the underlying water column. Comparisons between model computations and in situ measurements of irradiances made in Antarctic water show good agreement in the UV spectral range between 300 and 350 nm. The ratio of UVB (280-320 nm) to total (280-700 nm) irradiance also compared well. For a given ozone reduction the largest relative increase of UVB radiation arriving at the surface and penetrating to various depths in the ocean occurs at large solar zenith angles. At high latitudes the most pronounced increase in UVB exposure due to an ozone depletion occurs in the

  17. Replacements For Ozone-Depleting Foaming Agents

    NASA Technical Reports Server (NTRS)

    Blevins, Elana; Sharpe, Jon B.

    1995-01-01

    Fluorinated ethers used in place of chlorofluorocarbons and hydrochlorofluorocarbons. Replacement necessary because CFC's and HCFC's found to contribute to depletion of ozone from upper atmosphere, and manufacture and use of them by law phased out in near future. Two fluorinated ethers do not have ozone-depletion potential and used in existing foam-producing equipment, designed to handle liquid blowing agents soluble in chemical ingredients that mixed to make foam. Any polyurethane-based foams and several cellular plastics blown with these fluorinated ethers used in processes as diverse as small batch pours, large sprays, or double-band lamination to make insulation for private homes, commercial buildings, shipping containers, and storage tanks. Fluorinated ethers proved useful as replacements for CFC refrigerants and solvents.

  18. Replacements For Ozone-Depleting Foaming Agents

    NASA Technical Reports Server (NTRS)

    Blevins, Elana; Sharpe, Jon B.

    1995-01-01

    Fluorinated ethers used in place of chlorofluorocarbons and hydrochlorofluorocarbons. Replacement necessary because CFC's and HCFC's found to contribute to depletion of ozone from upper atmosphere, and manufacture and use of them by law phased out in near future. Two fluorinated ethers do not have ozone-depletion potential and used in existing foam-producing equipment, designed to handle liquid blowing agents soluble in chemical ingredients that mixed to make foam. Any polyurethane-based foams and several cellular plastics blown with these fluorinated ethers used in processes as diverse as small batch pours, large sprays, or double-band lamination to make insulation for private homes, commercial buildings, shipping containers, and storage tanks. Fluorinated ethers proved useful as replacements for CFC refrigerants and solvents.

  19. Climatic consequences of observed ozone loss in the 1980s: Relevance to the greenhouse problem

    NASA Technical Reports Server (NTRS)

    Molnar, G. I.; Ko, M. K. W.; Zhou, S.; Sze, N. D.

    1994-01-01

    Recently published findings using satellite and ground-based observations indicate a large winter and summertime decrease in the column abundance of ozone at high and middle latitudes during the last decade. Using a simple ozone depletion profile reflecting the observed decrease in ozone column abundance, Ramaswamy et al. (1992) showed that the negative radiative forcing that results from the ozone decrease between 1979 and 1990 approximately balanced the greenhouse climate forcing due to the chlorofluorocarbons emitted during the same period. Here, we extend the forcing analyses by calculating the equilibrium surface temperature response explicitly, using an updated version of the Atmospheric and Environmental Research two-dimensional radiative-dynamical seasonal model. The calculated steady state responses suggest that the surface cooling due to the ozone depletion in the lower stratosphere offsets about 30% of the surface warming due to greenhouse gases emitted during the same decade. The temperature offset is roughly a factor of 2 larger than the corresponding offset obtained from forcing intercomparisons. This result appears to be related to the climate feedback mechanisms operating in the model troposphere, most notably that associated with atmospheric meridional heat transport. Thus a comprehensive assessment of ozone change effects on the predicted greenhouse warming cannot be accomplished based on forcing evaluations alone. Our results also show that calculations adopting a seasonally and latitudinally dependent ozone depletion profile produce a negative forcing about 50% smaller than that calculated for the depletion profile used by Ramaswamy et al. (1992).

  20. Stratospheric ozone depletion and animal health.

    PubMed

    Mayer, S J

    1992-08-08

    There is an increasing concern over ozone depletion and its effects on the environment and human health. However, the increase in ultraviolet-B radiation (UV-B) that would result from significant losses of ozone is also potentially harmful to animals. Any increase in disease in domestic species would not only have serious animal welfare implications but may also be economically important. The diseases which are likely to increase if ozone depletion continues include the squamous cell carcinomas of the exposed, non-pigmented areas of cats, cattle, sheep and horses. Uberreiter's syndrome in dogs is also associated with exposure to UV-B and may be expected to increase, as may the severity of conditions such as infectious keratoconjunctivitis (New Forest eye) in cattle. Aquaculture systems in which fish often have little or no protection by shading may also be at risk. Cataracts and skin lesions have been associated with the exposure of farmed fish to ultraviolet radiation and have resulted in significant losses.

  1. Potential For Stratospheric Ozone Depletion During Carboniferous

    NASA Astrophysics Data System (ADS)

    Bill, M.; Goldstein, A. H.

    Methyl bromide (CH3Br) constitutes the largest source of bromine atoms to the strato- sphere whereas methyl chloride (CH3Cl) is the most abundant halocarbon in the tro- posphere. Both gases play an important role in stratospheric ozone depletion. For in- stance, Br coupled reactions are responsible for 30 to 50 % of total ozone loss in the polar vortex. Currently, the largest natural sources of CH3Br and CH3Cl appear to be biological production in the oceans, inorganic production during biomass burning and plant production in salt marsh ecosystems. Variations of paleofluxes of CH3Br and CH3Cl can be estimated by analyses of oceanic paleoproductivity, stratigraphic analyses of frequency and distribution of fossil charcoal indicating the occurrence of wildfires, and/or by paleoreconstruction indicating the extent of salt marshes. Dur- ing the lower Carboniferous time (Tournaisian-Visean), the southern margin of the Laurasian continent was characterized by charcoal deposits. Estimation on frequency of charcoal layers indicates that wildfires occur in a range of 3-35 years (Falcon-Lang 2000). This suggests that biomass burning could be an important source of CH3Br and CH3Cl during Tournaisian-Viesan time. During Tounaisian and until Merame- cian carbon and oxygen isotope records have short term oscillations (Bruckschen et al. 1999, Mii et al. 1999). Chesterian time (mid- Carboniferous) is marked by an in- crease in delta18O values ( ~ 2 permil) and an increase of glacial deposit frequency suggesting lower temperatures. The occurrence of glacial deposits over the paleopole suggests polar conditions and the associated special features of polar mete- orology such as strong circumpolar wind in the stratosphere (polar vortex) and polar stratospheric clouds. Thus, conditions leading to polar statospheric ozone depletion can be found. Simultaneously an increase in delta13C values is documented. We interpret the positive shift in delta13C as a result of higher bioproductivity

  2. Mechanisms of impact of greenhouse gases on the Earth's ozone layer in the Polar Regions

    NASA Astrophysics Data System (ADS)

    Zadorozhny, Alexander; Dyominov, Igor

    A numerical 2-D zonally averaged interactive dynamical radiative-photochemical model of the atmosphere including aerosol physics is used to examine the impact of the greenhouse gases CO2, CH4, and N2O on the future long-term changes of the Earth's ozone layer, in particular on its expected recovery after reduction of anthropogenic discharges of chlorine and bromine compounds into the atmosphere. The model allows calculating self-consistently diabatic circu-lation, temperature, gaseous composition of the troposphere and stratosphere at latitudes from the North to South Poles, as well as distribution of sulphate aerosol particles and polar strato-spheric clouds (PSCs) of types I and II. The scenarios of expected changes of the anthropogenic pollutants for the period from 1980 through 2050 are taken from Climate Change 2001. The processes, which determine the influence of anthropogenic growth of atmospheric abun-dance of the greenhouse gases on the long-term changes of the Earth's ozone layer in the Polar Regions, have been studied in details. Expected cooling of the stratosphere caused by increases of greenhouse gases, most importantly CO2, essentially influences the ozone layer by two ways: through temperature dependencies of the gas phase reaction rates and through enhancement of polar ozone depletion via increased PSC formation. The model calculations show that a weak-ness in efficiencies of all gas phase catalytic cycles of the ozone destruction due to cooling of the stratosphere is a dominant mechanism of the impact of the greenhouse gases on the ozone layer in Antarctic as well as at the lower latitudes. This mechanism leads to a significant acceleration of the ozone layer recovery here because of the greenhouse gases growth. On the contrary, the mechanism of the impact of the greenhouse gases on the ozone through PSC modification be-gins to be more effective in Arctic in comparison with the gas phase mechanism in springs after about 2020, which leads to retard

  3. Ozone depletion in tropospheric volcanic plumes

    NASA Astrophysics Data System (ADS)

    Vance, Alan; McGonigle, Andrew J. S.; Aiuppa, Alessandro; Stith, Jeffrey L.; Turnbull, Kate; von Glasow, Roland

    2010-11-01

    We measured ozone (O3) concentrations in the atmospheric plumes of the volcanoes St. Augustine (1976), Mt. Etna (2004, 2009) and Eyjafjallajökull (2010) and found O3 to be strongly depleted compared to the background at each volcano. At Mt. Etna O3 was depleted within tens of seconds from the crater, the age of the St. Augustine plumes was on the order of hours, whereas the O3 destruction in the plume of Eyjafjallajökull was maintained in 1-9 day old plumes. The most likely cause for this O3 destruction are catalytic bromine reactions as suggested by a model that manages to reproduce the very early destruction of O3 but also shows that O3 destruction is ongoing for several days. Given the observed rapid and sustained destruction of O3, heterogeneous loss of O3 on ash is unlikely to be important.

  4. Producing, Importing, and Exporting Ozone-Depleting Substances

    EPA Pesticide Factsheets

    Overview page provides links to information on producing, importing, and exporting ozone-depleting substances, including information about the HCFC allowance system, importing, labeling, recordkeeping and reporting.

  5. A search for relativistic electron induced stratospheric ozone depletion

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.

    1994-01-01

    Possible ozone changes at 1 mb associated with the time variation and precipitation of relativistic electrons are investigated by examining the NIMBUS 7 SBUV ozone data set and corresponding temperatures derived from NMC data. No ozone depletion was observed in high-latitude summer when temperature fluctuations are small. In winter more variation in ozone occurs, but large temperature changes make it difficult to identify specific ozone decreases as being the result of relativistic electron precipitation.

  6. Environmental effects of ozone depletion and its interactions with climate change: progress report, 2007.

    PubMed

    2008-01-01

    This year the Montreal Protocol celebrates its 20th Anniversary. In September 1987, 24 countries signed the Montreal Protocol on Substances that Deplete the Ozone Layer. Today 191 countries have signed and have met strict commitments on phasing out of ozone depleting substances with the result that a 95% reduction of these substances has been achieved. The Montreal Protocol has also contributed to slowing the rate of global climate change, since most of the ozone depleting substances are also effective greenhouse gases. Even though much has been achieved, the future of the stratospheric ozone layer relies on full compliance of the Montreal Protocol by all countries for the remaining substances, including methyl bromide, as well as strict monitoring of potential risks from the production of substitute chemicals. Also the ozone depleting substances existing in banks and equipment need special attention to prevent their release to the stratosphere. Since many of the ozone depleting substances already in the atmosphere are long-lived, recovery cannot be immediate and present projections estimate a return to pre-1980 levels by 2050 to 2075. It has also been predicted that the interactions of the effects of the ozone layer and that of other climate change factors will become increasingly important.

  7. International aspects of restrictions of ozone-depleting substances

    SciTech Connect

    McDonald, S.C.

    1989-10-01

    This report summarizes international efforts to protect stratospheric ozone. Also included in this report is a discussion of activities in other countries to meet restrictions in the production and use of ozone-depleting substances. Finally, there is a brief presentation of trade and international competitiveness issues relating to the transition to alternatives for the regulated chlorofluorocarbons (CFCs) and halons. The stratosphere knows no international borders. Just as the impact of reduced stratospheric ozone will be felt internationally, so protection of the ozone layer is properly an international effort. Unilateral action, even by a country that produces and used large quantities of ozone-depleting substances, will not remedy the problem of ozone depletion if other countries do not follow suit. 32 refs., 7 tabs.

  8. About ozone depletion in stratosphere over Brazil in last decade

    NASA Astrophysics Data System (ADS)

    Martin, Inácio M.; Imai, Takeshi; Seguchi, Tomio

    The depletion of stratospheric ozone, resulting from the emission of chlorofluorocarbons (CFCs), has become a major issue since 1980. The decrease in stratospheric ozone over the polar regions has been pronounced at the South Pole than at the North Pole. In mid-latitude and equatorial regions, ozone depletion becomes less important; it depends on seasonal effects and on the characteristics of a particular region. The detailed mechanism by which the polar ozone holes form is different from that for the mid-latitude thinning, but the most important process in both trends is the catalytic destruction of ozone by atomic chlorine and bromine. The main source of these halogen atoms in the stratosphere is photodissociation of CFC compounds, commonly called freons, and of bromofluorocarbon compounds known as halons. These compounds are transported into the stratosphere after being emitted at the surface. Both ozone depletion mechanisms strengthened as emissions of CFCs and halons increased [1]. Measurements of stratospheric ozone carried out on several locations in Brazil and on the South Pole in the last decade (1996-2005), using detectors placed on ground, stratospheric balloons and Earth Probe TOMS satellites, are presented here. Detailed series analysis from 1980 up to the present describes a mean ozone depletion of 4[1] http://en.wikipedia.org/wiki/Ozone/depletion.

  9. Ozone depletion: 20 Years after the alarm

    SciTech Connect

    Not Available

    1994-08-15

    Scientific curiosity in 1973 led to the challenge of determining the ultimate atmospheric fate of the chlorofluoromethanes, CFC-11 (CCl[sub 3]F) and CFC-12 (CCl[sub 2]F[sub 2]), whose presence at measurable levels in surface air had been detected only two years earlier. In retrospect, the decision to pursue the chemistry of CFC molecules to their final destruction and beyond foreordained an unusual outcome because CFCs are chemically inert and easily survive under almost all natural conditions. By midsummer 1994, the world is well on its way in transition to a CFC-free economy, although not yet to a CFC-free atmosphere. The rates of increase in atmospheric concentration for the three major CFCs (CFC-11, -12, and -113) have all slowed markedly in response to the restrictions of the revised Montreal protocol. Because of their long lifetimes, however, significant but gradually diminishing quantities of CFCs will remain in the atmosphere throughout the 21st century. Atomic chlorine will continue to be released into the stratosphere as long as CFCs persist, and ozone depletion will follow. The existence of the Montreal protocol and the agreement among industrial, governmental, and university scientists on its wisdom offers considerable promise for the handling of future global environmental problems.

  10. STRATOSPHERIC OZONE DEPLETION: A FOCUS ON EPA'S RESEARCH

    EPA Science Inventory

    In September of 1987 the United States, along with 26 other countries, signed a landmark treaty to limit and subsequently, through revisions, phase out the production of all significant ozone depleting substances. Many researchers suspected that these chemicals, especially chl...

  11. STRATOSPHERIC OZONE DEPLETION: A FOCUS ON EPA'S RESEARCH

    EPA Science Inventory

    In September of 1987 the United States, along with 26 other countries, signed a landmark treaty to limit and subsequently, through revisions, phase out the production of all significant ozone depleting substances. Many researchers suspected that these chemicals, especially chl...

  12. Ozone Depletion, UVB and Atmospheric Chemistry

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.

    1999-01-01

    The primary constituents of the Earth's atmosphere are molecular nitrogen and molecular oxygen. Ozone is created when ultraviolet light from the sun photodissociates molecular oxygen into two oxygen atoms. The oxygen atoms undergo many collisions but eventually combine with a molecular oxygen to form ozone (O3). The ozone molecules absorb ultraviolet solar radiation, primarily in the wavelength region between 200 and 300 nanometers, resulting in the dissociation of ozone back into atomic oxygen and molecular oxygen. The oxygen atom reattaches to an O2 molecule, reforming ozone which can then absorb another ultraviolet photon. This sequence goes back and forth between atomic oxygen and ozone, each time absorbing a uv photon, until the oxygen atom collides with and ozone molecule to reform two oxygen molecules.

  13. Ozone depletion in the Austral spring from UV microsatellite instrument

    NASA Astrophysics Data System (ADS)

    Fernandez-Saldivar, J. A.; Underwood, C. I.; Mackin, S.

    2007-10-01

    The Ozone Mapping Detector (OMAD) on board FASat-Bravo micro-satellite observed backscattered UV radiation to retrieve atmospheric ozone with low-spatial-resolution (150 x 150 km). This relatively coarse resolution with continuous global coverage allowed the observation of the seasonal ozone layer depletion over Antarctica in the austral spring in 1998. Previous analysis of this instrument have shown agreement in the radiances observed by OMAD and NASA's Total Ozone Mapping Spectrometer (TOMS-EP); these have even indicated the detection of an apparently higher ozone content anomaly due to a volcanic cloud of Nyamuragira volcano during its eruption in October 1998 [1]. A new improved version of the simplified algorithm used in OMAD data has been applied to the austral region to determine the total Ozone content. The new data processing allowed the observation of the development of the ozone depletion in 1998 from September to early December when ozone depletion normally occurs. The OMAD results showed good agreement overall when compared with those obtained from TOMS-EP despite their intrinsic instrumental differences. Results indicate Ozone contents lower than 150 Dobson Units (DU) in the Antarctic region with absolute errors less than 10 % in the vertical column content and high cross-correlations when compared with TOMS-EP. The value of this low-cost earth observation approach is discussed on the potential of such missions to provide additional atmospheric observations of large-scale phenomena.

  14. Impact of ozone depletion on immune function

    SciTech Connect

    Jeevan, A.; Kripke, M.L. . Dept. of Immunology)

    1993-06-01

    Depletion of stratospheric ozone is expected to lead to an increase in the amount of UV-B radiation present in sunlight. In addition to its well known ability to cause skin cancer, UV-B radiation has been shown to alter the immune system. The immune system is the body's primary defense mechanism against infectious diseases and protects against the development of certain types of cancer. Any impairment of immune function may jeopardize health by increasing susceptibility to infectious diseases, increasing the severity of infections, or delaying recovery for infections. In addition, impaired immune function can increase the incidence of certain cancers, particularly cancers of the skin. Research carried out with laboratory animals over the past 15 years has demonstrated that exposure of the skin to UV-B radiation can suppress certain types of immune responses. These include rejection of UV-induced skin cancers and melanomas, contact allergy reactions to chemicals, delayed-type hypersensitivity responses to microbial and other antigens, and phagocytosis and elimination of certain bacteria from lymphoid tissues. Recent studies with mycobacterial infection of mice demonstrated that exposure to UV-B radiation decreased the delayed hypersensitivity response to mycobacterial antigens and increased the severity of infection. In humans, UV-B radiation has also been shown to impair the contact allergy response. These studies demonstrate that UV radiation can decrease immune responses in humans and laboratory and raise the possibility that increased exposure to UV-B radiation could adversely affect human health by increasing the incidence or severity of certain infectious diseases.

  15. Ozone Depletion Potential of CH3Br

    NASA Technical Reports Server (NTRS)

    Sander, Stanley P.; Ko, Malcolm K. W.; Sze, Nien Dak; Scott, Courtney; Rodriquez, Jose M.; Weisenstein, Debra K.

    1998-01-01

    The ozone depletion potential (ODP) of methyl bromide (CH3Br) can be determined by combining the model-calculated bromine efficiency factor (BEF) for CH3Br and its atmospheric lifetime. This paper examines how changes in several key kinetic data affect BEF. The key reactions highlighted in this study include the reaction of BrO + H02, the absorption cross section of HOBr, the absorption cross section and the photolysis products of BrON02, and the heterogeneous conversion of BrON02 to HOBR and HN03 on aerosol particles. By combining the calculated BEF with the latest estimate of 0.7 year for the atmospheric lifetime of CH3Br, the likely value of ODP for CH3Br is 0.39. The model-calculated concentration of HBr (approximately 0.3 pptv) in the lower stratosphere is substantially smaller than the reported measured value of about I pptv. Recent publications suggested models can reproduce the measured value if one assumes a yield for HBr from the reaction of BrO + OH or from the reaction of BrO + H02. Although the DeAlore et al. evaluation concluded any substantial yield of HBr from BrO + HO2 is unlikely, for completeness, we calculate the effects of these assumed yields on BEF for CH3Br. Our calculations show that the effects are minimal: practically no impact for an assumed 1.3% yield of HBr from BrO + OH and 10% smaller for an assumed 0.6% yield from BrO + H02.

  16. Ozone Depletion Potential of CH3Br

    NASA Technical Reports Server (NTRS)

    Sander, Stanley P.; Ko, Malcolm K. W.; Sze, Nien Dak; Scott, Courtney; Rodriquez, Jose M.; Weisenstein, Debra K.

    1998-01-01

    The ozone depletion potential (ODP) of methyl bromide (CH3Br) can be determined by combining the model-calculated bromine efficiency factor (BEF) for CH3Br and its atmospheric lifetime. This paper examines how changes in several key kinetic data affect BEF. The key reactions highlighted in this study include the reaction of BrO + H02, the absorption cross section of HOBr, the absorption cross section and the photolysis products of BrON02, and the heterogeneous conversion of BrON02 to HOBR and HN03 on aerosol particles. By combining the calculated BEF with the latest estimate of 0.7 year for the atmospheric lifetime of CH3Br, the likely value of ODP for CH3Br is 0.39. The model-calculated concentration of HBr (approximately 0.3 pptv) in the lower stratosphere is substantially smaller than the reported measured value of about I pptv. Recent publications suggested models can reproduce the measured value if one assumes a yield for HBr from the reaction of BrO + OH or from the reaction of BrO + H02. Although the DeAlore et al. evaluation concluded any substantial yield of HBr from BrO + HO2 is unlikely, for completeness, we calculate the effects of these assumed yields on BEF for CH3Br. Our calculations show that the effects are minimal: practically no impact for an assumed 1.3% yield of HBr from BrO + OH and 10% smaller for an assumed 0.6% yield from BrO + H02.

  17. Ozone depletion over the polar caps caused by solar protons

    SciTech Connect

    Stephenson, J.A.E.; Scourfield, M.W.J. )

    1992-12-24

    Energetic solar protons are a natural source of ozone depletion due to nitric oxides they produce in the earth's atmosphere. In March 1989, following a period of intense solar activity, the TOMS instrument aboard the Nimbus 7 satellite recorded very similar ozone losses over both polar caps for areas extending from 90[degrees] to 70[degrees]. Ozone depletions of 7.4 [times] 10[sup 9] kg for the south polar cap and 8.0 [times] 10[sup 9] kg for the north polar cap indicate the degree of symmetry over the polar caps. 11 refs., 6 figs.

  18. The sensitivity of polar ozone depletion to proposed geoengineering schemes.

    PubMed

    Tilmes, Simone; Müller, Rolf; Salawitch, Ross

    2008-05-30

    The large burden of sulfate aerosols injected into the stratosphere by the eruption of Mount Pinatubo in 1991 cooled Earth and enhanced the destruction of polar ozone in the subsequent few years. The continuous injection of sulfur into the stratosphere has been suggested as a "geoengineering" scheme to counteract global warming. We use an empirical relationship between ozone depletion and chlorine activation to estimate how this approach might influence polar ozone. An injection of sulfur large enough to compensate for surface warming caused by the doubling of atmospheric CO2 would strongly increase the extent of Arctic ozone depletion during the present century for cold winters and would cause a considerable delay, between 30 and 70 years, in the expected recovery of the Antarctic ozone hole.

  19. Ozone depletion and climate change: impacts on UV radiation.

    PubMed

    Bais, A F; McKenzie, R L; Bernhard, G; Aucamp, P J; Ilyas, M; Madronich, S; Tourpali, K

    2015-01-01

    We assess the importance of factors that determine the intensity of UV radiation at the Earth's surface. Among these, atmospheric ozone, which absorbs UV radiation, is of considerable importance, but other constituents of the atmosphere, as well as certain consequences of climate change, can also be major influences. Further, we assess the variations of UV radiation observed in the past and present, and provide projections for the future. Of particular interest are methods to measure or estimate UV radiation at the Earth's surface. These are needed for scientific understanding and, when they are sufficiently sensitive, they can serve as monitors of the effectiveness of the Montreal Protocol and its amendments. Also assessed are several aspects of UV radiation related to biological effects and health. The implications for ozone and UV radiation from two types of geoengineering methods that have been proposed to combat climate change are also discussed. In addition to ozone effects, the UV changes in the last two decades, derived from measurements, have been influenced by changes in aerosols, clouds, surface reflectivity, and, possibly, by solar activity. The positive trends of UV radiation observed after the mid-1990s over northern mid-latitudes are mainly due to decreases in clouds and aerosols. Despite some indications from measurements at a few stations, no statistically significant decreases in UV-B radiation attributable to the beginning of the ozone recovery have yet been detected. Projections for erythemal irradiance (UVery) suggest the following changes by the end of the 21(st) century (2090-2100) relative to the present time (2010-2020): (1) Ozone recovery (due to decreasing ozone-depleting substances and increasing greenhouse gases) would cause decreases in UVery, which will be highest (up to 40%) over Antarctica. Decreases would be small (less than 10%) outside the southern Polar Regions. A possible decline of solar activity during the 21(st) century

  20. Detecting ozone- and greenhouse gas-driven wind trends with observational data.

    PubMed

    Lee, Sukyoung; Feldstein, Steven B

    2013-02-01

    Modeling studies suggest that Antarctic ozone depletion and, to a lesser degree, greenhouse gas (GHG) increase have caused the observed poleward shift in the westerly jet during the austral summer. Similar studies have not been performed previously with observational data because of difficulties in separating the two contributions. By applying a cluster analysis to daily ERA-Interim data, we found two 7- to 11-day wind clusters, one resembling the models' responses to GHG forcing and the other resembling ozone depletion. The trends in the clusters' frequency of occurrence indicate that the ozone contributed about 50% more than GHG toward the jet shift, supporting the modeling results. Moreover, tropical convection apparently plays an important role for the GHG-driven trend.

  1. Antarctic springtime ozone depletion computed from temperature observations

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.; Schoeberl, Mark R.; Newman, Paul A.

    1988-01-01

    An observationally based, mechanistic dynamical model is used to simulate the decline of total ozone during September and October for the years 1979 through 1986. Vertical velocities derived from observed stratospheric temperature changes and computed radiative heating rates are used to advect an ozone mixing ratio profile during the Antarctic spring period. An early August 1982 Syowa balloonsonde ozone profile is used to initialize the computations. The model reasonably simulates the September and October changes in total ozone, considering the uncertainties in the observed data and the radiative heating. The simulated decline is found to be very sensitive to the choice of initial ozone profile and to small changes in the radiative heating. The results of this study suggest that the dynamical hypothesis of the Antarctic ozone depletion is both quantitatively credible and consistent with the observed temperature changes.

  2. Northern Hemisphere Winter Climate Response to Greenhouse Gas, Ozone, Solar and Volcanic Forcing

    NASA Technical Reports Server (NTRS)

    Shindell, Drew T.; Schmidt, Gavin A.; Miller, Ron L.; Rind, David; Hansen, James E. (Technical Monitor)

    2001-01-01

    The Goddard Institute for Space Studies (GISS) climate/middle atmosphere model has been used to study the impacts of increasing greenhouse gases, polar ozone depletion, volcanic eruptions, and solar cycle variability. We focus on the projection of the induced responses onto Northern Hemisphere winter surface climate. Changes in the model's surface climate take place largely through enhancement of existing variability patterns, with greenhouse gases, polar ozone depletion and volcanic eruptions primarily affecting the Arctic Oscillation (AO) pattern. Perturbations descend from the stratosphere to the surface in the model by altering the propagation of planetary waves coming up from the surface, in accord with observational evidence. Models lacking realistic stratospheric dynamics fail to capture these wave flux changes. The results support the conclusion that the stratosphere plays a crucial role in recent AO trends. We show that in our climate model, while ozone depletion has a significant effect, greenhouse gas forcing is the only one capable of causing the large, sustained increase in the AO observed over recent decades. This suggests that the AO trend, and a concurrent strengthening of the stratospheric vortex over the Arctic, are very likely anthropogenic in origin.

  3. The chemistry of stratospheric ozone depletion

    SciTech Connect

    Tuck, A.

    1997-01-01

    In the early 1980`s the Antarctic ozone hole was discovered. The ozone loss was 50 percent in the lower stratosphere during springtime, which is made possible by the conditions over Antarctica in winter. The absence of sunlight in the stratosphere during polar winter causes the stratospheric air column there to cool and sink, drawing air from lower latitudes into the upper stratosphere. This lower-latitude air gets closer to the Earth`s axis of rotation as it moves poleward and is accelerated by the need to conserve angular momentum to greater and greater westerly wind speeds forming a vortex bounded by the polar night jet stream. The air entering the vortex contains reactive ozone-destroying species. The observed ozone losses occurred concurrently with increases of chlorofluorocarbon increases.

  4. Efficiency of short-lived halogens at influencing climate through depletion of stratospheric ozone

    NASA Astrophysics Data System (ADS)

    Hossaini, R.; Chipperfield, M. P.; Montzka, S. A.; Rap, A.; Dhomse, S.; Feng, W.

    2015-03-01

    Halogens released from long-lived anthropogenic substances, such as chlorofluorocarbons, are the principal cause of recent depletion of stratospheric ozone, a greenhouse gas. Recent observations show that very short-lived substances, with lifetimes generally under six months, are also an important source of stratospheric halogens. Short-lived bromine substances are produced naturally by seaweed and phytoplankton, whereas short-lived chlorine substances are primarily anthropogenic. Here we used a chemical transport model to quantify the depletion of ozone in the lower stratosphere from short-lived halogen substances, and a radiative transfer model to quantify the radiative effects of that ozone depletion. According to our simulations, ozone loss from short-lived substances had a radiative effect nearly half that from long-lived halocarbons in 2011 and, since pre-industrial times, has contributed a total of about -0.02 W m-2 to global radiative forcing. We find natural short-lived bromine substances exert a 3.6 times larger ozone radiative effect than long-lived halocarbons, normalized by halogen content, and show atmospheric levels of dichloromethane, a short-lived chlorine substance not controlled by the Montreal Protocol, are rapidly increasing. We conclude that potential further significant increases in the atmospheric abundance of short-lived halogen substances, through changing natural processes or continued anthropogenic emissions, could be important for future climate.

  5. The Effect of Climate Change on Ozone Depletion through Changes in Stratospheric Water Vapour

    NASA Technical Reports Server (NTRS)

    Kirk-Davidoff, Daniel B.; Hintsa, Eric J.; Anderson, James G.; Keith, David W.

    1999-01-01

    Several studies have predicted substantial increases in Arctic ozone depletion due to the stratospheric cooling induced by increasing atmospheric CO2 concentrations. But climate change may additionally influence Arctic ozone depletion through changes in the water vapor cycle. Here we investigate this possibility by combining predictions of tropical tropopause temperatures from a general circulation model with results from a one-dimensional radiative convective model, recent progress in understanding the stratospheric water vapor budget, modelling of heterogeneous reaction rates and the results of a general circulation model on the radiative effect of increased water vapor. Whereas most of the stratosphere will cool as greenhouse-gas concentrations increase, the tropical tropopause may become warmer, resulting in an increase of the mean saturation mixing ratio of water vapor and hence an increased transport of water vapor from the troposphere to the stratosphere. Stratospheric water vapor concentration in the polar regions determines both the critical temperature below which heterogeneous reactions on cold aerosols become important (the mechanism driving enhanced ozone depletion) and the temperature of the Arctic vortex itself. Our results indicate that ozone loss in the later winter and spring Arctic vortex depends critically on water vapor variations which are forced by sea surface temperature changes in the tropics. This potentially important effect has not been taken into account in previous scenarios of Arctic ozone loss under climate change conditions.

  6. Ozone layer depletion simulation in an Environmental Chemistry course.

    NASA Astrophysics Data System (ADS)

    Cano, G. S.; Gavilán, I. C.; Garcia-Reynoso, J. A.; Santos, E.; Mendoza, A.; Perea, B.

    2015-12-01

    The reactions taking place between the ozone (O3) and various compounds present in the stratosphere has been studied extensively. When the balance between these reactions breakdown, destruction of ozone is favored. Here we create an experiment for and Environmental Chemistry laboratory course where students evaluate the ozone behavior by comparing its reactivity to various physical and chemical conditions; and observe the destruction of ozone by the action of halogenated compounds by means of volumetric technic. The conditions used are: (1) Ozone vs. Time; (2) Ozone + UV vs. Time; (3) Ozone + halogenated compound vs. Time; and (4) Ozone + UV + halogenated compound vs. Time. The results show that the O3 breaks down rapidly within about 25 min (Fig). They also explain the chemical reactions that occur in the destruction and generation of the ozone layer and demonstrate ozone depletion through the presence of halogenated compounds. The aim of this work is to bring the knowledge gained from theory into practice and thus the possibility of developing a critical attitude towards various environmental problems that arise today.

  7. Depletion of tropospheric ozone associated with mineral dust outbreaks.

    PubMed

    Soler, Ruben; Nicolás, J F; Caballero, S; Yubero, E; Crespo, J

    2016-10-01

    From May to September 2012, ozone reductions associated with 15 Saharan dust outbreaks which occurred between May to September 2012 have been evaluated. The campaign was performed at a mountain station located near the eastern coast of the Iberian Peninsula. The study has two main goals: firstly, to analyze the decreasing gradient of ozone concentration during the course of the Saharan episodes. These gradients vary from 0.2 to 0.6 ppb h(-1) with an average value of 0.39 ppb h(-1). The negative correlation between ozone and coarse particles occurs almost simultaneously. Moreover, although the concentration of coarse particles remained high throughout the episode, the time series shows the saturation of the ozone loss. The highest ozone depletion has been obtained during the last hours of the day, from 18:00 to 23:00 UTC. Outbreaks registered during this campaign have been more intense in this time slot. The second objective is to establish from which coarse particle concentration a significant ozone depletion can be observed and to quantify this reduction. In this regard, it has been confirmed that when the hourly particle concentration recorded during the Saharan dust outbreaks is above the hourly particle median values (N > N-median), the ozone concentration reduction obtained is statistically significant. An average ozone reduction of 5.5 % during Saharan events has been recorded. In certain cases, this percentage can reach values of higher than 15 %.

  8. Impact of polar ozone depletion on subtropical precipitation.

    PubMed

    Kang, S M; Polvani, L M; Fyfe, J C; Sigmond, M

    2011-05-20

    Over the past half-century, the ozone hole has caused a poleward shift of the extratropical westerly jet in the Southern Hemisphere. Here, we argue that these extratropical circulation changes, resulting from ozone depletion, have substantially contributed to subtropical precipitation changes. Specifically, we show that precipitation in the southern subtropics in austral summer increases significantly when climate models are integrated with reduced polar ozone concentrations. Furthermore, the observed patterns of subtropical precipitation change, from 1979 to 2000, are very similar to those in our model integrations, where ozone depletion alone is prescribed. In both climate models and observations, the subtropical moistening is linked to a poleward shift of the extratropical westerly jet. Our results highlight the importance of polar regions for the subtropical hydrological cycle.

  9. Ozone dynamics and snow-atmosphere exchanges during ozone depletion events at Barrow, Alaska

    NASA Astrophysics Data System (ADS)

    Helmig, Detlev; Boylan, Patrick; Johnson, Bryan; Oltmans, Sam; Fairall, Chris; Staebler, Ralf; Weinheimer, Andrew; Orlando, John; Knapp, David J.; Montzka, Denise D.; Flocke, Frank; Frieß, Udo; Sihler, Holger; Shepson, Paul B.

    2012-10-01

    The behavior of lower atmospheric ozone and ozone exchanges at the snow surface were studied using a suite of platforms during the Ocean-Atmosphere-Sea Ice-Snow (OASIS) Spring 2009 experiment at an inland, coastal site east of Barrow, Alaska. A major objective was to investigate if and how much chemistry at the snow surface at the site contributes to springtime ozone depletion events (ODEs). Between March 8 and April 16, seven ODEs, with atmospheric ozone dropping below 1.0 ppbv, were observed. The depth of the ozone-depleted layer was variable, extending from the surface to ˜200-800 m. ODEs most commonly occurred during low wind speed conditions with flow coming from the Arctic Ocean. Two high-sensitivity ozone chemiluminescence instruments were used to accurately define the remaining sub-ppbv ozone levels during ODEs. These measurements showed variable residual ODE ozone levels ranging between 0.010 and 0.100 ppbv. During the most extended ODE, when ozone remained below 1.0 ppbv for over 78 h, these measurements showed a modest ozone recovery or production in the early afternoon hours, resulting in increases in the ozone mixing ratio of 0.100 to 0.800 ppbv. The comparison between high-sensitivity ozone measurements and BrO measured by longpath differential absorption spectroscopy (DOAS) during ODEs indicated that at low ozone levels formation of BrO is controlled by the amount of available ozone. Measurements of ozone in air drawn from below the snow surface showed depleted ozone in the snowpack, with levels consistently remaining <6 ppbv independent of above-surface ambient air concentrations. The snowpack was always a sink of ozone. Ozone deposition velocities determined from ozone surface flux measurements by eddy covariance were on the order of 0.01 cm s-1, which is of similar magnitude as ozone uptake rates found over snow at other polar sites that are not subjected to ODEs. The results from these multiple platform measurements unequivocally show that snow

  10. Fundamental differences between Arctic and Antarctic ozone depletion.

    PubMed

    Solomon, Susan; Haskins, Jessica; Ivy, Diane J; Min, Flora

    2014-04-29

    Antarctic ozone depletion is associated with enhanced chlorine from anthropogenic chlorofluorocarbons and heterogeneous chemistry under cold conditions. The deep Antarctic "hole" contrasts with the generally weaker depletions observed in the warmer Arctic. An unusually cold Arctic stratospheric season occurred in 2011, raising the question of how the Arctic ozone chemistry in that year compares with others. We show that the averaged depletions near 20 km across the cold part of each pole are deeper in Antarctica than in the Arctic for all years, although 2011 Arctic values do rival those seen in less-depleted years in Antarctica. We focus not only on averages but also on extremes, to address whether or not Arctic ozone depletion can be as extreme as that observed in the Antarctic. This information provides unique insights into the contrasts between Arctic and Antarctic ozone chemistry. We show that extreme Antarctic ozone minima fall to or below 0.1 parts per million by volume (ppmv) at 18 and 20 km (about 70 and 50 mbar) whereas the lowest Arctic ozone values are about 0.5 ppmv at these altitudes. At a higher altitude of 24 km (30-mbar level), no Arctic data below about 2 ppmv have been observed, including in 2011, in contrast to values more than an order of magnitude lower in Antarctica. The data show that the lowest ozone values are associated with temperatures below -80 °C to -85 °C depending upon altitude, and are closely associated with reduced gaseous nitric acid concentrations due to uptake and/or sedimentation in polar stratospheric cloud particles.

  11. Fundamental differences between Arctic and Antarctic ozone depletion

    PubMed Central

    Solomon, Susan; Haskins, Jessica; Ivy, Diane J.; Min, Flora

    2014-01-01

    Antarctic ozone depletion is associated with enhanced chlorine from anthropogenic chlorofluorocarbons and heterogeneous chemistry under cold conditions. The deep Antarctic “hole” contrasts with the generally weaker depletions observed in the warmer Arctic. An unusually cold Arctic stratospheric season occurred in 2011, raising the question of how the Arctic ozone chemistry in that year compares with others. We show that the averaged depletions near 20 km across the cold part of each pole are deeper in Antarctica than in the Arctic for all years, although 2011 Arctic values do rival those seen in less-depleted years in Antarctica. We focus not only on averages but also on extremes, to address whether or not Arctic ozone depletion can be as extreme as that observed in the Antarctic. This information provides unique insights into the contrasts between Arctic and Antarctic ozone chemistry. We show that extreme Antarctic ozone minima fall to or below 0.1 parts per million by volume (ppmv) at 18 and 20 km (about 70 and 50 mbar) whereas the lowest Arctic ozone values are about 0.5 ppmv at these altitudes. At a higher altitude of 24 km (30-mbar level), no Arctic data below about 2 ppmv have been observed, including in 2011, in contrast to values more than an order of magnitude lower in Antarctica. The data show that the lowest ozone values are associated with temperatures below −80 °C to −85 °C depending upon altitude, and are closely associated with reduced gaseous nitric acid concentrations due to uptake and/or sedimentation in polar stratospheric cloud particles. PMID:24733920

  12. Ozone depletion, related UVB changes and increased skin cancer incidence

    NASA Astrophysics Data System (ADS)

    Kane, R. P.

    1998-03-01

    Stratospheric ozone at middle latitudes shows a seasonal variation of about +/-20%, a quasi-biennial oscillation of 1-10% range and a long-term variation in which the level was almost steady up to about 1979 and declined thereafter to the present day by about 10%. These variations are expected to be reflected in solar UVB observed at the ground, but in an opposite direction. Thus UVB should have had a long-term increase of about 10-20%, which should cause an increase in skin cancer incidence of about 20-40%. Skin cancer incidence has increased all over the world, e.g. about 90% in USA during 1974-1990. It is popularly believed that this increase in skin cancer incidence is related to the recent ozone depletion. This seems to be incorrect, for two reasons. Firstly, the observed skin cancer increase is too large (90%) compared with the expected value (40%) from ozone depletion. Secondly, cancer does not develop immediately after exposure to solar UVB. The sunburns may occur within hours; but cancer development and detection may take years, even decades. Hence the observed skin cancer increase since 1974 (no data available for earlier periods) must have occurred due to exposure to solar UVB in the 1950s and 1960s, when there was no ozone depletion. Thus, the skin cancer increase must be attributed to harmful solar UVB levels existing even in the 1960s, accentuated later not by ozone depletion (which started only much later, by 1979) but by other causes, such as a longer human life span, better screening, increasing tendencies of sunbathing at beaches, etc., in affluent societies. On the other hand, the recent ozone depletion and the associated UVB increases will certainly take their toll; only that the effects will not be noticed now but years or decades from now. The concern for the future expressed in the Montreal Protocol for reducing ozone depletion by controlling CFC production is certainly justified, especially because increased UVB is harmful to animal and

  13. Antarctic winter mercury and ozone depletion events over sea ice

    NASA Astrophysics Data System (ADS)

    Nerentorp Mastromonaco, M.; Gårdfeldt, K.; Jourdain, B.; Abrahamsson, K.; Granfors, A.; Ahnoff, M.; Dommergue, A.; Méjean, G.; Jacobi, H.-W.

    2016-03-01

    During atmospheric mercury and ozone depletion events in the springtime in polar regions gaseous elemental mercury and ozone undergo rapid declines. Mercury is quickly transformed into oxidation products, which are subsequently removed by deposition. Here we show that such events also occur during Antarctic winter over sea ice areas, leading to additional deposition of mercury. Over four months in the Weddell Sea we measured gaseous elemental, oxidized, and particulate-bound mercury, as well as ozone in the troposphere and total and elemental mercury concentrations in snow, demonstrating a series of depletion and deposition events between July and September. The winter depletions in July were characterized by stronger correlations between mercury and ozone and larger formation of particulate-bound mercury in air compared to later spring events. It appears that light at large solar zenith angles is sufficient to initiate the photolytic formation of halogen radicals. We also propose a dark mechanism that could explain observed events in air masses coming from dark regions. Br2 that could be the main actor in dark conditions was possibly formed in high concentrations in the marine boundary layer in the dark. These high concentrations may also have caused the formation of high concentrations of CHBr3 and CH2I2 in the top layers of the Antarctic sea ice observed during winter. These new findings show that the extent of depletion events is larger than previously believed and that winter depletions result in additional deposition of mercury that could be transferred to marine and terrestrial ecosystems.

  14. The recent findings of the "Scientific Assessment of Ozone Depletion: 2010" and the World Avoided by the Montreal Protocol

    NASA Astrophysics Data System (ADS)

    Newman, P. A.; Scientific Assessment Panel to the Montreal Protocol

    2011-12-01

    The ozone layer is the Earth's natural sunscreen, blocking harmful solar ultraviolet radiation. In 1974, Mario Molina and F. Sherwood Rowland proposed that the ozone layer could be depleted by chlorine released from human-produced chlorofluorocarbons (CFCs). Follow-up science investigations supported this hypothesis, leading to the landmark 1987 Montreal Protocol on Substances That Deplete the Ozone Layer (a protocol to the Vienna Convention for the Protection of the Ozone Layer). One of the Montreal Protocol provisions is that science assessments on ozone depletion be written and submitted to the signatory Parties every 4 years. In this talk, I will primarily focus on the science findings from the recently published "Scientific Assessment of Ozone Depletion: 2010". This assessment is written and reviewed (multiple times) by the international science community. The 2010 assessment is the latest in a long series of reports that provide the science foundation for the Montreal Protocol. This assessment demonstrates that the Montreal Protocol is working, and that there are early signs that ozone is beginning to respond to decreasing CFC levels. There are now state-of-the-art simulations that show that the ozone layer would have been largely destroyed if CFCs had not been regulated, and therefore extreme levels of UV radiation have been avoided. The 2010 assessment also spotlights new insights into the impact of ozone depletion on surface climate, and climate impacts on ozone. However, the assessment also reveals that greenhouse gases are modifying the stratosphere and that the ozone layer will evolve into a different state than its pre-industrial values - you can't go home again.

  15. What Could Be Causing Global Ozone Depletion

    NASA Technical Reports Server (NTRS)

    Singer, S. Fred

    1990-01-01

    The reported decline trend in global ozone between 1970 and 1986 may be in part an artifact of the analysis; the trend value appears to depend on the time interval selected for analysis--in relation to the 11-year solar cycle. If so, then the decline should diminish as one approaches solar maximum and includes data from 1987 to 1990. If the decline is real, its cause could be the result of natural and human factors other than just chlorofluorocarbons.

  16. GLOBAL CHANGE RESEARCH NEWS #7: ENVIRONMENTAL EFFECTS OF OZONE DEPLETION

    EPA Science Inventory

    This edition focuses on a recent UNEP report entitled, "Environmental Effects of Ozone Depletion: 1998 Assessment." Dr. Richard Zepp (ORD/NERL) is one of the Lead Authors of this report. The 1998 assessment focuses on new information produced since 1994. It also includes earlie...

  17. GLOBAL CHANGE RESEARCH NEWS #7: ENVIRONMENTAL EFFECTS OF OZONE DEPLETION

    EPA Science Inventory

    This edition focuses on a recent UNEP report entitled, "Environmental Effects of Ozone Depletion: 1998 Assessment." Dr. Richard Zepp (ORD/NERL) is one of the Lead Authors of this report. The 1998 assessment focuses on new information produced since 1994. It also includes earlie...

  18. New evidence for ozone depletion in the upper stratosphere

    NASA Astrophysics Data System (ADS)

    Claude, H.; Schönenborn, F.; Steinbrecht, W.; Vandersee, W.

    1994-11-01

    Differential absorption lidar measurements at the Meteorological Observatory Hohenpeißenberg between 1987 and 1993 show a statistically significant ozone decrease between 32 and 42 km, peaking at about -1.7% per year at 39 km altitude. This depletion is higher than reported by SAGE II or SBUV, yet the Hohenpeißenberg data agree very well with the results from Umkehr measurements. The observed ozone trend is in the upper range of predictions from photochemical models (-0.5 to -1.5% per year), whereas SBUV and SAGE II results are close to the lower end of the simulations. The agreement with photochemical models indicates that the depletion is most likely caused by catalytic ozone destruction through anthropogenic chlorine.

  19. Mount Pinatubo aerosols, chlorofluorocarbons, and ozone depletion

    SciTech Connect

    Brasseur, G.; Granier, C. )

    1992-08-28

    The injection into the stratosphere of large quantities of sulfur during the June 1991 eruption of Mount Pinatube (Philippines) and the subsequent formation of sulfate aerosol particles have generated a number of perturbations in the atmosphere with potential effects on the Earth's climate. Changes in the solar and infrared radiation budget caused by the eruption should produce a cooling of the troposphere and a warming of the lower stratosphere. These changes could affect atmospheric circulation. In addition, heterogeneous chemical reactions on the surface of sulfate aerosol particles render the ozone molecules more vulnerable to atmospheric chlorine and hence to man-made chlorofluorocarbons.

  20. Laboratory Studies of Halogen Oxides Important to Stratospheric Ozone Depletion

    NASA Astrophysics Data System (ADS)

    Wilmouth, D. M.; Klobas, J. E.; Anderson, J. G.

    2016-12-01

    Inorganic chlorine and bromine molecules are primarily responsible for stratospheric ozone destruction, with BrO, ClO, and ClOOCl comprising the two reaction cycles that cause most polar ozone losses. Despite comprehensive international treaties regulating CFCs and halons, seasonal polar ozone depletion will likely continue for decades to come. Accurate spectroscopic and kinetic measurements of inorganic bromine and chlorine molecules obtained in the laboratory are essential for reducing uncertainty in atmospheric models, better interpreting atmospheric field measurements, and forming trusted projections of future ozone changes. Here we present results from recent work in our laboratory using absorption spectroscopy and atomic resonance fluorescence detection to determine rate constants of halogen reactions, the equilibrium constant of ClO/ClOOCl, and absorption cross sections of several halogen oxides using a new cold trap-thermal desorption approach.

  1. Depletion of Arctic ozone in the winter 1990

    NASA Technical Reports Server (NTRS)

    Koike, M.; Kondo, Y.; Hayashi, M.; Iwasaka, Y.; Newman, P. A.

    1991-01-01

    Ozone mixing ratios were measured by ozonesondes on board balloons launched from Esrange, near Kiruna, Sweden (68 deg N, 20 deg E) from January 11 to February 9, 1990. The data obtained prior to a sudden warming on February 7, 1990 show that at potential temperatures between 460 and 640 K, the ozone mixing ratio just inside the polar vortex was systematically smaller than that outside, the largest difference being 29 percent at around 525 K. The ozone mixing ratio at 525 K inside the vortex decreased at a rate of about 1.5 percent per day between January 26 and February 4. The temperatures simultaneously observed were quite often low enough to allow for formation of nitric acid trihydrate particles around this altitude. Depletion of ozone due to highly perturbed chemical conditions in late January and early February is strongly suggested.

  2. Can ozone depletion and global warming interact to produce rapid climate change?

    PubMed Central

    Hartmann, Dennis L.; Wallace, John M.; Limpasuvan, Varavut; Thompson, David W. J.; Holton, James R.

    2000-01-01

    The atmosphere displays modes of variability whose structures exhibit a strong longitudinally symmetric (annular) component that extends from the surface to the stratosphere in middle and high latitudes of both hemispheres. In the past 30 years, these modes have exhibited trends that seem larger than their natural background variability, and may be related to human influences on stratospheric ozone and/or atmospheric greenhouse gas concentrations. The pattern of climate trends during the past few decades is marked by rapid cooling and ozone depletion in the polar lower stratosphere of both hemispheres, coupled with an increasing strength of the wintertime westerly polar vortex and a poleward shift of the westerly wind belt at the earth's surface. Annular modes of variability are fundamentally a result of internal dynamical feedbacks within the climate system, and as such can show a large response to rather modest external forcing. The dynamics and thermodynamics of these modes are such that strong synergistic interactions between stratospheric ozone depletion and greenhouse warming are possible. These interactions may be responsible for the pronounced changes in tropospheric and stratospheric climate observed during the past few decades. If these trends continue, they could have important implications for the climate of the 21st century. PMID:10677475

  3. 26 CFR 52.4681-1 - Taxes imposed with respect to ozone-depleting chemicals.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 17 2014-04-01 2014-04-01 false Taxes imposed with respect to ozone-depleting... to ozone-depleting chemicals. (a) Taxes imposed. Sections 4681 and 4682 impose the following taxes with respect to ozone-depleting chemicals (ODCs): (1) Tax on ODCs. Section 4681(a)(1) imposes a tax...

  4. 48 CFR 211.271 - Elimination of use of class I ozone-depleting substances.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... class I ozone-depleting substances. 211.271 Section 211.271 Federal Acquisition Regulations System... Using and Maintaining Requirements Documents 211.271 Elimination of use of class I ozone-depleting substances. See subpart 223.8 for restrictions on contracting for ozone-depleting substances....

  5. 26 CFR 52.4681-1 - Taxes imposed with respect to ozone-depleting chemicals.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 17 2011-04-01 2011-04-01 false Taxes imposed with respect to ozone-depleting... to ozone-depleting chemicals. (a) Taxes imposed. Sections 4681 and 4682 impose the following taxes with respect to ozone-depleting chemicals (ODCs): (1) Tax on ODCs. Section 4681(a)(1) imposes a tax...

  6. 48 CFR 211.271 - Elimination of use of class I ozone-depleting substances.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... class I ozone-depleting substances. 211.271 Section 211.271 Federal Acquisition Regulations System... Using and Maintaining Requirements Documents 211.271 Elimination of use of class I ozone-depleting substances. See subpart 223.8 for restrictions on contracting for ozone-depleting substances....

  7. 26 CFR 52.4681-1 - Taxes imposed with respect to ozone-depleting chemicals.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 17 2012-04-01 2012-04-01 false Taxes imposed with respect to ozone-depleting... to ozone-depleting chemicals. (a) Taxes imposed. Sections 4681 and 4682 impose the following taxes with respect to ozone-depleting chemicals (ODCs): (1) Tax on ODCs. Section 4681(a)(1) imposes a tax...

  8. 26 CFR 52.4681-1 - Taxes imposed with respect to ozone-depleting chemicals.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 17 2013-04-01 2013-04-01 false Taxes imposed with respect to ozone-depleting... to ozone-depleting chemicals. (a) Taxes imposed. Sections 4681 and 4682 impose the following taxes with respect to ozone-depleting chemicals (ODCs): (1) Tax on ODCs. Section 4681(a)(1) imposes a tax...

  9. 48 CFR 211.271 - Elimination of use of class I ozone-depleting substances.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... class I ozone-depleting substances. 211.271 Section 211.271 Federal Acquisition Regulations System... Using and Maintaining Requirements Documents 211.271 Elimination of use of class I ozone-depleting substances. See subpart 223.8 for restrictions on contracting for ozone-depleting substances....

  10. 48 CFR 211.271 - Elimination of use of class I ozone-depleting substances.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... class I ozone-depleting substances. 211.271 Section 211.271 Federal Acquisition Regulations System... Using and Maintaining Requirements Documents 211.271 Elimination of use of class I ozone-depleting substances. See subpart 223.8 for restrictions on contracting for ozone-depleting substances....

  11. 48 CFR 211.271 - Elimination of use of class I ozone-depleting substances.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... class I ozone-depleting substances. 211.271 Section 211.271 Federal Acquisition Regulations System... Using and Maintaining Requirements Documents 211.271 Elimination of use of class I ozone-depleting substances. See subpart 223.8 for restrictions on contracting for ozone-depleting substances....

  12. [Biomedical and economic consequences of stratosphere ozone depletion].

    PubMed

    Strzhizhovskiĭ, A D

    1998-01-01

    Information on possible human health-changes associated with stratosphere ozone depletion and amplification factor (% increase of the stick rate by 1% decrease of ozone) values for acute (erythema, keratitis, cataract, immunosuppression) and chronic (skin cancer, cataract) effects of natural UV-radiation was analysed. Amplification factor (AF) values for acute UV-effects increase with degree of ozone depletion. For degrees less than 12.5% they are independent of latitude and equal to 1.9 for erythema, 1.3-1.5 for keratitis, 1.7-2.3 for cataract and 0.9-1.1 for immunosuppression. AF values for incidence of non-melanoma skin cancer are independent of age, higher in males than females, and higher for squamous cell carcinoma, than for basal cell carcinoma. Their optimal estimations for whites equal to 2.7 for basal cell and 4.6 for squamous cell carcinoma. AF values for incidence of cutaneous malignant melanoma range between 1 and 2, for melanoma mortality--between 0.3 and 2. AF values for incidence of cataract range between 0.3 and 1.2 with optimal estimations between 0.6 and 0.8. Prognosis of non-melanoma skin cancer and cataract incidences, melanoma mortality and economic loss for different scenarios of stratosphere ozone depletion are presented.

  13. Tropical circulation and precipitation response to ozone depletion and recovery

    NASA Astrophysics Data System (ADS)

    Brönnimann, Stefan; Jacques-Coper, Martín; Rozanov, Eugene; Fischer, Andreas M.; Morgenstern, Olaf; Zeng, Guang; Akiyoshi, Hideharu; Yamashita, Yousuke

    2017-06-01

    Among the few well established changes in atmospheric circulation in recent decades are those caused by stratospheric ozone depletion. They include a strengthening and poleward contraction of the westerly atmospheric circulation over the Southern extratropics, i.e. a strengthening Southern Annular Mode (SAM), in austral spring and summer. Associated effects on extratropical temperature and precipitation and more recently subtropical precipitation have been documented and are understood in a zonal mean framework. We present zonally asymmetric effects of ozone depletion that reach into the tropics and affect atmospheric circulation and precipitation, including the South Pacific Convergence Zone (SPCZ), the most important rainband of the Southern Hemisphere. Using observation-based analyses and model simulations we show that over the 1961-1996 period, ozone depletion led to increased precipitation at the northern flank of the SPCZ and to decreased precipitation to the south. The effects originate from a flow pattern over the southwestern Pacific that extends equatorward and alters the propagation of synoptic waves and thus the position of the SPCZ. Model simulations suggest that anticipated stratospheric ozone recovery over the next decades will reverse these effects.

  14. Human Health Effects of Ozone Depletion From Stratospheric Aircraft

    NASA Technical Reports Server (NTRS)

    Wey, Chowen (Technical Monitor)

    2001-01-01

    This report presents EPA's initial response to NASA's request to advise on potential environmental policy issues associated with the future development of supersonic flight technologies. Consistent with the scope of the study to which NASA and EPA agreed, EPA has evaluated only the environmental concerns related to the stratospheric ozone impacts of a hypothetical HSCT fleet, although recent research indicates that a fleet of HSCT is predicted to contribute to climate warming as well. This report also briefly describes the international and domestic institutional frameworks established to address stratospheric ozone depletion, as well as those established to control pollution from aircraft engine exhaust emissions.

  15. Relative Contribution of Greenhouse Gases and Ozone Change to Temperature Trends in the Stratosphere: A Chemistry/Climate Model Study

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Douglass, A. R.; Newman, P. A.; Pawson, S.; Schoeberl, M. R.

    2006-01-01

    Long-term changes in greenhouse gases, primarily carbon dioxide, are expected to lead to a warming of the troposphere and a cooling of the stratosphere. We examine the cooling of the stratosphere and compare the contributions greenhouse gases and ozone change for the decades between 1980 and 2000. We use 150 years of simulation done with our coupled chemistry/climate model (GEOS 4 GCM with GSFC CTM chemistry) to calculate temperatures and constituents fiom,1950 through 2100. The contributions of greenhouse gases and ozone to temperature change are separated by a time-series analysis using a linear trend term throughout the period to represent the effects of greenhouse gases and an equivalent effective stratospheric chlorine (EESC) term to represent the effects of ozone change. The temperature changes over the 150 years of the simulation are dominated by the changes in greenhouse gases. Over the relatively short period (approx. 20 years) of ozone decline between 1980 and 2000 changes in ozone are competitive with changes in greenhouse gases. The changes in temperature induced by the ozone change are comparable to, but smaller than, those of greenhouse gases in the upper stratosphere (1-3 hPa) at mid latitudes. The ozone term dominates the temperature change near both poles with a negative temperature change below about 3-5 hPa and a positive change above. At mid latitudes in the upper stratosphere and mesosphere (above about 1 hPa) and in the middle stratosphere (3 to 70 ma), the greenhouse has term dominates. From about 70 hPa down to the tropopause at mid latitudes, cooling due to ozone changes is the largest influence on temperature. Over the 150 years of the simulation, the change in greenhouse gases is the most important contributor to temperature change. Ozone caused a perturbation that is expected to reverse over the coming decades. We show a model simulation of the expected temperature change over the next two decades (2006-2026). The simulation shows a

  16. Ozone depletion. (Latest citations from the NTIS database). Published Search

    SciTech Connect

    Not Available

    1993-04-01

    The bibliography contains citations concerning studies of atmospheric chemistry and modeling of ozone depletion in Antarctica, and the consequences of the depletion on ultraviolet radiation levels. The studies involve chemical reactions in the atmosphere, including temperature dynamics, possible changes in solar insolation, and effects of pollution from nitrogen, chloroflourocarbons, carbon dioxide, and methane. The studies involve references to observations of the ozonosphere and modeling of interactions worldwide, together with data on the sources of the natural and man-made pollutants. (Contains a minimum of 173 citations and includes a subject term index and title list.)

  17. Effects of Stratospheric Ozone Depletion the Environment and Agriculture

    NASA Astrophysics Data System (ADS)

    Ali, S. M.; Dash, Nutan Ku; Pradhan, Arjyadhara; Mishra, Sthita Prajna

    2012-09-01

    Ozone depletion results in greater amounts of UV-B radiation that had an impact on terrestrial and aquatic biogeochemical systems. Biogeochemical cycles were the complex interactions of physical, chemical, geological and biological processes that control the transport and transformation of substances in the natural environment and therefore the conditions that humans experience in Earth's system. The increased UV-B radiation impinging on terrestrial and aquatic systems, due to ozone depletion, results in changes in the trace gas exchange between the continents, oceans and the atmosphere. This had result in complex alterations to atmospheric chemistry, the global elemental cycles such as the carbon cycle, and had an impact on the survival and health of all organisms on Earth, including humans.

  18. Visualization of stratospheric ozone depletion and the polar vortex

    NASA Technical Reports Server (NTRS)

    Treinish, Lloyd A.

    1995-01-01

    Direct analysis of spacecraft observations of stratospheric ozone yields information about the morphology of annual austral depletion. Visual correlation of ozone with other atmospheric data illustrates the diurnal dynamics of the polar vortex and contributions from the upper troposphere, including the formation and breakup of the depletion region each spring. These data require care in their presentation to minimize the introduction of visualization artifacts that are erroneously interpreted as data features. Non geographically registered data of differing mesh structures can be visually correlated via cartographic warping of base geometries without interpolation. Because this approach is independent of the realization technique, it provides a framework for experimenting with many visualization strategies. This methodology preserves the fidelity of the original data sets in a coordinate system suitable for three-dimensional, dynamic examination of atmospheric phenomena.

  19. Ozone depletion - Ultraviolet radiation and phytoplankton biology in Antarctic waters

    NASA Technical Reports Server (NTRS)

    Smith, R. C.; Prezelin, B. B.; Baker, K. S.; Bidigare, R. R.; Boucher, N. P.; Coley, T.; Karentz, D.; Macintyre, S.; Matlick, H. A.; Menzies, D.

    1992-01-01

    The near-50-percent thinning of the stratospheric ozone layer over the Antarctic, with increased passage of mid-UV radiation to the surface of the Southern Ocean, has prompted concern over possible radiation damage to the near-surface phytoplankton communities that are the bases of Antarctic marine ecosystems. As the ozone layer thinned, a 6-week study of the marginal ice zone of the Bellingshousen Sea in the austral spring of 1990 noted sea-surface and depth-dependent ratios of mid-UV irradiance to total irradiance increased, and mid-UV inhibition of photosynthesis increased. A 6-12 percent reduction in primary production associated with ozone depletion was estimated to have occurred over the course of the present study.

  20. Heterogeneous reactions important in atmospheric ozone depletion: a theoretical perspective.

    PubMed

    Bianco, Roberto; Hynes, James T

    2006-02-01

    Theoretical studies of the mechanisms of several heterogeneous reactions involving ClONO(2), H(2)O, HCl, HBr, and H(2)SO(4) important in atmospheric ozone depletion are described, focused primarily on reactions on aqueous aerosol surfaces. Among the insights obtained is the active chemical participation of the surface water molecules in several of these reactions. The general methodology adopted allows reduction of these complex chemical problems to meaningful model systems amenable to quantum chemical calculations.

  1. The Antarctic ozone depletion caused by Erebus volcano gas emissions

    NASA Astrophysics Data System (ADS)

    Zuev, V. V.; Zueva, N. E.; Savelieva, E. S.; Gerasimov, V. V.

    2015-12-01

    Heterogeneous chemical reactions releasing photochemically active molecular chlorine play a key role in Antarctic stratospheric ozone destruction, resulting in the Antarctic ozone hole. Hydrogen chloride (HCl) is one of the principal components in these reactions on the surfaces of polar stratospheric clouds (PSCs). PSCs form during polar nights at extremely low temperatures (lower than -78 °C) mainly on sulfuric acid (H2SO4) aerosols, acting as condensation nuclei and formed from sulfur dioxide (SO2). However, the cause of HCl and H2SO4 high concentrations in the Antarctic stratosphere, leading to considerable springtime ozone depletion, is still not clear. Based on the NCEP/NCAR reanalysis data over the last 35 years and by using the NOAA HYSPLIT trajectory model, we show that Erebus volcano gas emissions (including HCl and SO2) can reach the Antarctic stratosphere via high-latitude cyclones with the annual average probability Pbarann. of at least ∼0.235 (23.5%). Depending on Erebus activity, this corresponds to additional annual stratospheric HCl mass of 1.0-14.3 kilotons (kt) and SO2 mass of 1.4-19.7 kt. Thus, Erebus volcano is the natural and powerful source of additional stratospheric HCl and SO2, and hence, the cause of the Antarctic ozone depletion, together with man-made chlorofluorocarbons.

  2. 77 FR 58035 - Protection of Stratospheric Ozone: Listing of Substitutes for Ozone-Depleting Substances-Fire...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-19

    ... use; therefore, the ozone depletion potential (ODP), global warming potential (GWP), and atmospheric... available fire protection options including new, improved technology for early warning and smoke detection...

  3. Ozone Depletion, Greenhouse Gases, and Climate Change. Proceedings of a Joint Symposium by the Board on Atmospheric Sciences and Climate and the Committee on Global Change, National Research Council (Washington, D.C., March 23, 1988).

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC.

    The motivation for the organization of this symposium was the accumulation of evidence from many sources, both short- and long-term, that the global climate is in a state of change. Data which defy integrated explanation including temperature, ozone, methane, precipitation and other climate-related trends have presented troubling problems for…

  4. A feasibility study of methods for stopping the depletion of ozone over Antarctica

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Ways of stopping the ozone depletion in the ozone hole over Antarctica were studied. The basic objectives were: (1) to define and understand the phenomenon of the ozone hole; (2) to determine possible methods of stopping the ozone depletion; (3) to identify unknowns about the hole and possible solutions. Two basic ways of attacking the problem were identified. First is replenishment of ozone as it is being depleted. Second is elimination of ozone destroying agents from the atmosphere. The second method is a more permanent form of the solution. Elimination and replenishment methods are discussed in detail.

  5. The relationship between skin cancers, solar radiation and ozone depletion.

    PubMed Central

    Moan, J.; Dahlback, A.

    1992-01-01

    During the period 1957-1984 the annual age-adjusted incidence rate of cutaneous malignant melanoma (CMM) increased by 350% for men and 440% for women in Norway. The annual exposure to carcinogenic sunlight in Norway, calculated by use of measured ozone levels, showed no increasing trend during the same period. Thus, ozone depletion is not a cause of the increasing trend of the incidence rates of skin cancers. The incidence rates of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) increase with decreasing latitude in Norway. The same is true for CMM in Norway, Sweden, and Finland. Our data were used to estimate the implications of a future ozone depletion for the incidence rates of skin cancer: a 10% ozone depletion was found to give rise to a 16-18% increase in the incidence rate of SCC (men and women), a 19% increase in the incidence rate of CMM for men and a 32% increase in the incidence rate of CMM for women. The difference between the numbers for men and women is almost significant and may be related to a different intermittent exposure pattern to sunlight of the two sexes. The increasing trend in the incidence rates of CMM is strongest for the trunk and lower extremities of women, followed by that for the trunk of men. The increasing incidence rates of skin cancers as well as the changing pattern of incidence on different parts of the body is most likely due to changing habits of sun exposure. Comparisons of relative densities of CMM, SCC, LMM and SCC falling per unit area of skin at different parts of the body indicate that sun exposure is the main cause of these cancer forms although other unknown factors may play significant roles as well. For the population as a whole sun exposure during vacations to sunny countries has so far been of minor importance in skin cancer induction. PMID:1616864

  6. Modeling the climate impact of Southern Hemisphere ozone depletion: The importance of the ozone data set

    NASA Astrophysics Data System (ADS)

    Young, P. J.; Davis, S. M.; Hassler, B.; Solomon, S.; Rosenlof, K. H.

    2014-12-01

    The ozone hole is an important driver of recent Southern Hemisphere (SH) climate change, and capturing these changes is a goal of climate modeling. Most climate models are driven by off-line ozone data sets. Previous studies have shown that there is a substantial range in estimates of SH ozone depletion, but the implications of this range have not been examined systematically. We use a climate model to evaluate the difference between using the ozone forcing (Stratospheric Processes and their Role in Climate (SPARC)) used by many Intergovernmental Panel on Climate Change Fifth Assessment Report (Coupled Model Intercomparison Project) models and one at the upper end of the observed depletion estimates (Binary Database of Profiles (BDBP)). In the stratosphere, we find that austral spring/summer polar cap cooling, geopotential height decreases, and zonal wind increases in the BDBP simulations are all doubled compared to the SPARC simulations, while tropospheric responses are 20-100% larger. These results are important for studies attempting to diagnose the climate fingerprints of ozone depletion.

  7. Changes in tropospheric composition and air quality due to stratospheric ozone depletion and climate change.

    PubMed

    Wilson, S R; Solomon, K R; Tang, X

    2007-03-01

    known usage and atmospheric loss processes, tropospheric concentrations of HFC-134a, the main human-made source of trifluoroacetic acid (TFA), is increasing rapidly. As HFC-134a is a potent greenhouse gas, this increasing concentration has implications for climate change. However, the risks to humans and the environment from substances, such as TFA, produced by atmospheric degradation of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are considered minimal. Perfluoropolyethers, commonly used as industrial heat transfer fluids and proposed as chlorohydrofluorocarbon (CHFC) substitutes, show great stability to chemical degradation in the atmosphere. These substances have been suggested as substitutes for CHFCs but, as they are very persistent in the atmosphere, they may be important contributors to global warming. It is not known whether these substances will contribute significantly to global warming and its interaction with ozone depletion but they should be considered for further evaluation.

  8. The Effects of Volcano-Induced Ozone Depletion on Short-lived Climate Forcing in the Arctic

    NASA Astrophysics Data System (ADS)

    Ward, P. L.

    2012-12-01

    Antarctic snow and decreasing solar zenith angles at higher latitudes. The second largest ozone depletion was in the Arctic at the times and places of greatest winter warming. Average ozone at four stations in Canada (43-59°N) compared to the 1961-1970 mean were 6% lower in December 2010 after the eruption of Eyjafjallajökull and 11% lower in December 2011 after the eruption of Grímsvötn. In 2012, ozone levels were still 10% lower in March and 7% lower in July. The regions and timing of this depletion are the regions and times of unusually warm temperatures and drought in North America during 2011-2012. The Dust Bowl droughts in 1934 and 1936 show a similar temporal relationship to a highly unusual sequence of five VEI=4-5 eruptions around the Pacific in 1931-1933. Major increases in global pollution were from 1950-1970 while ozone-destroying tropospheric chlorine rose from 1970 to 1994, along with ocean heat content and mean temperature. Pollution does not seem to cause an increase in warming until ozone depletion allows more UV into the lower troposphere. Pollutants decrease surface solar radiation but also reduce Arctic-snow albedo. Widespread observations imply that ozone depletion and associated photodissociation cause substantial warming. Several issues regarding the microphysics of absorption and radiation by greenhouse gases must be resolved before we can quantify their relative importance.

  9. Ozone depletion at northern and southern latitudes derived from January 1979 to December 1991 Total Ozone Mapping Spectrometer Data

    SciTech Connect

    Herman, J.R.; McPeters, R.; Larko, D.

    1993-07-20

    Long-term ozone depletion rates (percentage change) have been computed from 13 years of Nimbus 8/Total Ozone Mapping Spectrometer (TOMS) data as a function of latitude, longitude, and month for the period January 1, 1979, to December 31, 1991. In both hemispheres the amount of ozone has decreased at latitudes above 30{degrees} by amounts that are larger than predicted by homogeneous chemistry models for the 13-year time period. The largest rates of ozone decrease occur in the southern hemisphere during winter and spring, with partial recovery during the summer and autumn. Outside of the Antarctic ozone hole region, the 12-year ozone depletion rates reach 8-10% per decade during the winter and spring at 55{degrees}S. Ozone depletion rates in excess of 7% per decade occur over populated regions in the southern hemisphere poleward of 45{degrees}S for 7 months of the year. Similar rates of decrease occur during northern winter and spring over large populated regions. The enhanced zonal average ozone depletion rates at northern mid-latitudes (40-50{degrees}N) during January, February, and March, that correspond to five geographically localized regions of high ozone depletion rates, are probably associated with long-term dynamical or temperature changes. Only the equatorial band between {+-}20{degrees} shows little or no long-term ozone change since January 1979. Ozone time series data have been examined for effect of volcanic eruptions on stratospheric ozone observed by TOMS, with only the Mount Pinatubo stratospheric aerosol injection affecting ozone amounts for a few months after the eruption in June 1991. Errors caused by the short-term presence of stratospheric aerosols in the TOMS zonally averaged ozone data are less than 1% before correction, and have no significant effect on ozone trend determination. 49 refs., 6 figs., 2 tabs.

  10. Impact of rising greenhouse gas concentrations on future tropical ozone and UV exposure

    NASA Astrophysics Data System (ADS)

    Meul, Stefanie; Dameris, Martin; Langematz, Ulrike; Abalichin, Janna; Kerschbaumer, Andreas; Kubin, Anne; Oberländer-Hayn, Sophie

    2016-03-01

    Future projections of tropical total column ozone (TCO) are challenging, as its evolution is affected not only by the expected decline of ozone depleting substances but also by the uncertain increase of greenhouse gas (GHG) emissions. To assess the range of tropical TCO projections, we analyze simulations with a chemistry-climate model forced by three different GHG scenarios (Representative Concentration Pathway (RCP) 4.5, RCP6.0, and RCP8.5). We find that tropical TCO will be lower by the end of the 21st century compared to the 1960s in all scenarios with the largest decrease in the medium RCP6.0 scenario. Uncertainties of the projected TCO changes arise from the magnitude of stratospheric column decrease and tropospheric ozone increase which both strongly vary between the scenarios. In the three scenario simulations the stratospheric column decrease is not compensated by the increase in tropospheric ozone. The concomitant increase in harmful ultraviolet irradiance reaches up to 15% in specific regions in the RCP6.0 scenario.

  11. Ozone Depletion Potentials of HCFC-123 and HCFC-124

    NASA Astrophysics Data System (ADS)

    Riepe, E. L.; Patten, K. O.; Wuebbles, D. J.

    2005-05-01

    The Montreal Protocol has phased out most chlorinated and brominated compounds because of their great efficiency in depleting ozone in the stratosphere. Compounds such as CHCl2CF3 (HCFC-123) and CHClFCF3 (HCFC-124) are being used in commercial refrigeration units and have much shorter atmospheric lifetimes than the chlorofluorocarbons they replace. Despite their small resulting Ozone Depletion Potentials (ODPs), these compounds are still currently expected to be eliminated under the existing Protocol, but there remain questions about finding suitable replacements that would not have other environmental effects. The HCFC-123 and HCFC-124 model-calculated atmospheric lifetimes of 1.3 years and 5.8 years are much shorter compared to the 45 years of CCl3F (CFC-11). In this study, we have reevaluated these compounds with an updated version of the UIUC two-dimensional chemical transport model and with the MOZART (version 3) three-dimensional chemical-transport model. The new version of the two-dimensional model gives ODPs of 0.012 and 0.0125 for HCFC-123 and HCFC-124, respectively. The ODP for HCFC-123 agrees well with previously reported values while the ODP for HCFC-124 is much smaller than earlier estimates. These analyses along with those from the three-dimensional modeling studies will be discussed in the presentation.

  12. Ozone-depleting-substance control and phase-out plan

    SciTech Connect

    Nickels, J.M.; Brown, M.J.

    1994-07-01

    Title VI of the Federal Clean Air Act Amendments of 1990 requires regulation of the use and disposal of ozone-depleting substances (ODSs) (e.g., Halon, Freon). Several important federal regulations have been promulgated that affect the use of such substances at the Hanford Site. On April 23, 1993, Executive Order (EO) 12843, Procurement Requirements and Policies for Federal Agencies for Ozone-Depleting Substances (EPA 1993) was issued for Federal facilities to conform to the new US Environmental Protection Agency (EPA) regulations implementing the Clean Air Act of 1963 (CAA), Section 613, as amended. To implement the requirements of Title VI the US Department of Energy, Richland Operations Office (RL), issued a directive to the Hanford Site contractors on May 25, 1994 (Wisness 1994). The directive assigns Westinghouse Hanford Company (WHC) the lead in coordinating the development of a sitewide comprehensive implementation plan to be drafted by July 29, 1994 and completed by September 30, 1994. The implementation plan will address several areas where immediate compliance action is required. It will identify all current uses of ODSs and inventories, document the remaining useful life of equipment that contains ODS chemicals, provide a phase-out schedule, and provide a strategy that will be implemented consistently by all the Hanford Site contractors. This plan also addresses the critical and required elements of Federal regulations, the EO, and US Department of Energy (DOE) guidance. This plan is intended to establish a sitewide management system to address the clean air requirements.

  13. Newly detected ozone-depleting substances in the atmosphere

    NASA Astrophysics Data System (ADS)

    Laube, Johannes C.; Newland, Mike J.; Hogan, Christopher; Brenninkmeijer, Carl A. M.; Fraser, Paul J.; Martinerie, Patricia; Oram, David E.; Reeves, Claire E.; Röckmann, Thomas; Schwander, Jakob; Witrant, Emmanuel; Sturges, William T.

    2014-04-01

    Ozone-depleting substances emitted through human activities cause large-scale damage to the stratospheric ozone layer, and influence global climate. Consequently, the production of many of these substances has been phased out; prominent examples are the chlorofluorocarbons (CFCs), and their intermediate replacements, the hydrochlorofluorocarbons (HCFCs). So far, seven types of CFC and six types of HCFC have been shown to contribute to stratospheric ozone destruction. Here, we report the detection and quantification of a further three CFCs and one HCFC. We analysed the composition of unpolluted air samples collected in Tasmania between 1978 and 2012, and extracted from deep firn snow in Greenland in 2008, using gas chromatography with mass spectrometric detection. Using the firn data, we show that all four compounds started to emerge in the atmosphere in the 1960s. Two of the compounds continue to accumulate in the atmosphere. We estimate that, before 2012, emissions of all four compounds combined amounted to more than 74,000 tonnes. This is small compared with peak emissions of other CFCs in the 1980s of more than one million tonnes each year. However, the reported emissions are clearly contrary to the intentions behind the Montreal Protocol, and raise questions about the sources of these gases.

  14. Ozone depletion at northern and southern latitudes derived from January 1979 to December 1991 Total Ozone Mapping Spectrometer data

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Mcpeters, R.; Larko, D.

    1993-01-01

    An extended version of the Nimbus 7/TOMS ozone data set from the period January 1, 1979 to December 31, 1991 is presented. It is shown that the ozone-trend data indicate that regions of enhanced ozone depletion rates have formed at middle and high latitudes during recent years. The seasonal dependence and geographical extent of the enhanced ozone-depletion rates for the Northern and Southern hemispheres are examined. The variability of the long-term ozone trend determination is discussed via consideration of the differences among 11-, 12-, and 13-yr trend calculations. The effects of the Mount Pinatubo eruption and other volcanic eruptions on the TOMS equatorial zonal average ozone measurements, and its influence on long-term trend determinations are discussed. On the basis of a determination of the aerosol phase function using TOMS data, the effect of stratospheric aerosols on determination of ozone amounts from TOMS are shown to be less than 1 percent.

  15. Reply to "Comment on 'Cosmic-ray-driven reaction and greenhouse effect of halogenated molecules: Culprits for atmospheric ozone depletion and global climate change' by Dana Nuccitelli et al."

    NASA Astrophysics Data System (ADS)

    Lu, Q.-B.

    2014-04-01

    In the Comment by Nuccitelli et al., they make many false and invalid criticisms of the CFC-warming theory in my recent paper, and claim that their anthropogenic forcings including CO2 would provide a better explanation of the observed global mean surface temperature (GMST) data over the past 50 years. First, their arguments for no significant discrepancy between modeled and observed GMST changes and for no pause in recent global warming contradict the widely accepted fact and conclusion that were reported in the recent literature extensively. Second, their criticism that the key data used in my recent paper would be "outdated" and "flawed" is untrue as these data are still used in the recent or current literature including the newest (2013) IPCC Report and there is no considerable difference between the UK Met Office HadRCUT3 and HadRCUT4 GMST datasets. The use of even more recently computer-reconstructed total solar irradiance data (whatever have large uncertainties) for the period prior to 1976 would not change any of the conclusions in my paper, where quantitative analyses were emphasized on the influences of humans and the Sun on global surface temperature after 1970 when direct measurements became available. For the latter, the solar effect has been well shown to play only a negligible role in global surface temperature change since 1970, which is identical to the conclusion made in the 2013 IPCC Report. Third, their argument that the solar effect would not play a major role in the GMST rise of 0.2°C during 1850-1970 even contradicts the data and conclusion presented in a recent paper published in their Skeptical Science by Nuccitelli himself. Fourth, their comments also indicate their lack of understandings of the basic radiation physics of the Earth system as well as of the efficacies of different greenhouse gases in affecting global surface temperature. Their listed "methodological errors" are either trivial or non-existing. Fifth, their assertion that

  16. Impacts of stratospheric ozone depletion and recovery on wave propagation in the boreal winter stratosphere

    NASA Astrophysics Data System (ADS)

    Hu, Dingzhu; Tian, Wenshou; Xie, Fei; Wang, Chunxiao; Zhang, Jiankai

    2015-08-01

    This paper uses a state-of-the-art general circulation model to study the impacts of the stratospheric ozone depletion from 1980 to 2000 and the expected partial ozone recovery from 2000 to 2020 on the propagation of planetary waves in December, January, and February. In the Southern Hemisphere (SH), the stratospheric ozone depletion leads to a cooler and stronger Antarctic stratosphere, while the stratospheric ozone recovery has the opposite effects. In the Northern Hemisphere (NH), the impacts of the stratospheric ozone depletion on polar stratospheric temperature are not opposite to that of the stratospheric ozone recovery; i.e., the stratospheric ozone depletion causes a weak cooling and the stratospheric ozone recovery causes a statistically significant cooling. The stratospheric ozone depletion leads to a weakening of the Arctic polar vortex, while the stratospheric ozone recovery leads to a strengthening of the Arctic polar vortex. The cooling of the Arctic polar vortex is found to be dynamically induced via modulating the planetary wave activity by stratospheric ozone increases. Particularly interesting is that stratospheric ozone changes have opposite effects on the stationary and transient wave fluxes in the NH stratosphere. The analysis of the wave refractive index and Eliassen-Palm flux in the NH indicates (1) that the wave refraction in the stratosphere cannot fully explain wave flux changes in the Arctic stratosphere and (2) that stratospheric ozone changes can cause changes in wave propagation in the northern midlatitude troposphere which in turn affect wave fluxes in the NH stratosphere. In the SH, the radiative cooling (warming) caused by stratospheric ozone depletion (recovery) produces a larger (smaller) meridional temperature gradient in the midlatitude upper troposphere, accompanied by larger (smaller) zonal wind vertical shear and larger (smaller) vertical gradients of buoyancy frequency. Hence, there are more (fewer) transient waves

  17. High School and College Student Perceptions of the Ozone Depletion Problem.

    ERIC Educational Resources Information Center

    Groves, Fred; Pugh, Ava

    This paper examines the knowledge of high school biology students (n=107), undergraduate elementary education majors (n=42), and graduate students in an advanced elementary science methods course (n=22) about ozone depletion. The questionnaire used contained 30 items pertaining to ozone depletion which were divided into three subscales: (1)…

  18. Children's and Adults' Knowledge and Models of Reasoning about the Ozone Layer and Its Depletion.

    ERIC Educational Resources Information Center

    Leighton, Jacqueline P.; Bisanz, Gay L.

    2003-01-01

    Examines children's and adults' knowledge of the ozone layer and its depletion, whether this knowledge increases with age, and how the ozone layer and ozone hole might be structured as scientific concepts. Uses a standardized set of questions to interview children and adults in Canada. Discusses implications of the results for health…

  19. Children's and Adults' Knowledge and Models of Reasoning about the Ozone Layer and Its Depletion.

    ERIC Educational Resources Information Center

    Leighton, Jacqueline P.; Bisanz, Gay L.

    2003-01-01

    Examines children's and adults' knowledge of the ozone layer and its depletion, whether this knowledge increases with age, and how the ozone layer and ozone hole might be structured as scientific concepts. Uses a standardized set of questions to interview children and adults in Canada. Discusses implications of the results for health…

  20. Robust response of the Amundsen Sea Low to stratospheric ozone depletion

    NASA Astrophysics Data System (ADS)

    England, Mark R.; Polvani, Lorenzo M.; Smith, Karen L.; Landrum, Laura; Holland, Marika M.

    2016-08-01

    The effect of stratospheric ozone depletion on the Amundsen Sea Low (ASL), a climatological low-pressure center important for the climate of West Antarctica, remains uncertain. Using state-of-the-art climate models, we here show that stratospheric ozone depletion can cause a statistically significant deepening of the ASL in summer with an amplitude of approximately 1 hPa per decade. We are able to attribute the modeled changes in the ASL to stratospheric ozone depletion by contrasting ensembles of historical integrations with and without a realistic ozone hole. In the presence of very large natural variability, the robustness of the ozone impact on the ASL is established by (1) examining ensembles of model runs to isolate the forced response, (2) repeating the analysis with two different climate models, and (3) considering the entire period of stratospheric ozone depletion, the beginning of which predates the satellite era by a couple of decades.

  1. Use of Ozone-Depleting Substances. Direct final rule.

    PubMed

    2016-10-26

    The Food and Drug Administration (FDA, the Agency, or we) is amending its regulation on uses of ozone-depleting substances (ODSs), including chlorofluorocarbons (CFCs), to remove the designation for certain products as "essential uses" under the Clean Air Act. Essential-use products are exempt from the ban by FDA on the use of CFCs and other ODS propellants in FDA-regulated products and from the ban by the Environmental Protection Agency (EPA) on the use of ODSs in pressurized dispensers. The products that will no longer constitute an essential use are: Sterile aerosol talc administered intrapleurally by thoracoscopy for human use and metered-dose atropine sulfate aerosol human drugs administered by oral inhalation. FDA is taking this action because alternative products that do not use ODSs are now available and because these products are no longer being marketed in versions that contain ODSs.

  2. Alternatives to ozone depleting refrigerants in test equipment

    NASA Technical Reports Server (NTRS)

    Hall, Richard L.; Johnson, Madeleine R.

    1995-01-01

    This paper describes the initial results of a refrigerant retrofit project at the Aerospace Guidance and Metrology Center (AGMC) at Newark Air Force Base, Ohio. The objective is to convert selected types of test equipment to properly operate on hydrofluorocarbon (HFC) alternative refrigerants, having no ozone depleting potential, without compromising system reliability or durability. This paper discusses the primary technical issues and summarizes the test results for 17 different types of test equipment: ten environmental chambers, two ultralow temperature freezers, two coolant recirculators, one temperature control unit, one vapor degreaser, and one refrigerant recovery system. The postconversion performance test results have been very encouraging: system capacity and input power remained virtually unchanged. In some cases, the minimum operating temperature increased by a few degrees as a result of the conversion, but never beyond AGMC's functional requirements.

  3. Ab Initio Studies of Stratospheric Ozone Depletion Chemistry

    NASA Technical Reports Server (NTRS)

    Lee, Timothy J.; Head-Gordon, Martin; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    An overview of the current understanding of ozone depletion chemistry, particularly with regards the formation of the so-called Antarctic ozone hole, will be presented together with an outline as to how ab initio quantum chemistry can be used to further our understanding of stratospheric chemistry. The ability of modern state-of-the art ab initio quantum chemical techniques to characterize reliably the gas-phase molecular structure, vibrational spectrum, electronic spectrum, and thermal stability of fluorine, chlorine, bromine and nitrogen oxide species will be demonstrated by presentation of some example studies. The ab initio results will be shown to be in excellent agreement with the available experimental data, and where the experimental data are either not known or are inconclusive, the theoretical results are shown to fill in the gaps and to resolve experimental controversies. In addition, ab initio studies in which the electronic spectra and the characterization of excited electronic states of halogen oxide species will also be presented. Again where available, the ab initio results are compared to experimental observations, and are used to aid in the interpretation of experimental studies.

  4. Ab Initio Studies of Stratospheric Ozone Depletion Chemistry

    NASA Technical Reports Server (NTRS)

    Lee, Timothy J.; Head-Gordon, Martin; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    An overview of the current understanding of ozone depletion chemistry, particularly with regards the formation of the so-called Antarctic ozone hole, will be presented together with an outline as to how ab initio quantum chemistry can be used to further our understanding of stratospheric chemistry. The ability of modern state-of-the art ab initio quantum chemical techniques to characterize reliably the gas-phase molecular structure, vibrational spectrum, electronic spectrum, and thermal stability of fluorine, chlorine, bromine and nitrogen oxide species will be demonstrated by presentation of some example studies. The ab initio results will be shown to be in excellent agreement with the available experimental data, and where the experimental data are either not known or are inconclusive, the theoretical results are shown to fill in the gaps and to resolve experimental controversies. In addition, ab initio studies in which the electronic spectra and the characterization of excited electronic states of halogen oxide species will also be presented. Again where available, the ab initio results are compared to experimental observations, and are used to aid in the interpretation of experimental studies.

  5. Impact on ozone attainment of CFC (chlorofluorocarbon) controls used to prevent future depletion of stratospheric ozone

    SciTech Connect

    Harmon, D.L.; Smith, N.D.

    1988-04-01

    This paper discusses the impact on ozone attainment of chlorofluorocarbon (CFC) controls used to prevent future depletion of stratospheric ozone. It has been decided that allocated quotas offer the most-attractive approach to limiting the use of CFCs and brominated compounds (halons). This approach should provide for economically efficient reductions. It involves a minimum of administrative costs, is the most easily enforced option, and does not raise any potential legal issues that might result from other options. Control options that might be used by industry to achieve the necessary CFC reductions are evaluated in the Regulatory Impact Analysis (RIA). The most likely long-term control option which may be adopted by most application areas is a chemical substitute. With this option, it may be possible to eliminate 90% or more of the ozone-depleting CFC emissions. A variety of control options hold promise for short-term applicability. Some of the engineering controls may still be applied even after new chemical substitutes (e.g., HFC-134a and HCFC-123) are in use, since the higher cost of these substitutes may justify recovery. EPA is also considering the development of specific regulations limiting CFC and halon use for particular industries to supplement allocated quotas.

  6. Antarctic ozone depletion between 1960 and 1980 in observations and chemistry-climate model simulations

    NASA Astrophysics Data System (ADS)

    Langematz, Ulrike; Schmidt, Franziska; Kunze, Markus; Bodeker, Gregory E.; Braesicke, Peter

    2016-12-01

    The year 1980 has often been used as a benchmark for the return of Antarctic ozone to conditions assumed to be unaffected by emissions of ozone-depleting substances (ODSs), implying that anthropogenic ozone depletion in Antarctica started around 1980. Here, the extent of anthropogenically driven Antarctic ozone depletion prior to 1980 is examined using output from transient chemistry-climate model (CCM) simulations from 1960 to 2000 with prescribed changes of ozone-depleting substance concentrations in conjunction with observations. A regression model is used to attribute CCM modelled and observed changes in Antarctic total column ozone to halogen-driven chemistry prior to 1980. Wintertime Antarctic ozone is strongly affected by dynamical processes that vary in amplitude from year to year and from model to model. However, when the dynamical and chemical impacts on ozone are separated, all models consistently show a long-term, halogen-induced negative trend in Antarctic ozone from 1960 to 1980. The anthropogenically driven ozone loss from 1960 to 1980 ranges between 26.4 ± 3.4 and 49.8 ± 6.2 % of the total anthropogenic ozone depletion from 1960 to 2000. An even stronger ozone decline of 56.4 ± 6.8 % was estimated from ozone observations. This analysis of the observations and simulations from 17 CCMs clarifies that while the return of Antarctic ozone to 1980 values remains a valid milestone, achieving that milestone is not indicative of full recovery of the Antarctic ozone layer from the effects of ODSs.

  7. Ozone depletion, developing countries, and human rights: Seeking better ground on which to fight for protection of the ozone layer

    SciTech Connect

    Williams, V.

    1995-12-31

    I urge you not to take a complacent view of the situation. The state of depletion of the ozone layer continues to be alarming... In February, 1993, the ozone levels over North America and most of Europe were 20 percent below normal... Even now, millions of tons of CFC [chlorofluorocarbon] products are en route to their fatal stratospheric rendezvous... This exponential increase calls for increased reflection on the state of the ozone layer and calls for bold decisions.

  8. Ozone depletion continues at record levels - satellite data confirm CFCs as cause

    SciTech Connect

    1994-12-01

    In the stratosphere above the South Pole on 2 October 1994, researcher recorded ozone depletion levels nearly as large and as deep as those observed during the October 1993 record-settling depletion. In addition data gathered during the last three years by instruments on NASA`s upper Atmosphere Research Satellite, and readings from other instrumentation, have provided conclusive evidence that anthropogenic chlorine in the stratosphere causes the ozone depletion in the antarctic stratosphere. The article discusses the evidence. 2 figs.

  9. Lifetimes of Stratospheric Ozone-Depleting Substances, Their Replacements, and Related Species

    NASA Astrophysics Data System (ADS)

    Newman, P. A.; Ko, M. K.; Reimann, S.; Strahan, S. E.; Atlas, E. L.; Burkholder, J. B.; Chipperfield, M.; Engel, A.; Liang, Q.; Plumb, R. A.; Stolarski, R. S.

    2013-12-01

    Estimating the average lifetime of a chemical in the atmosphere is crucial to understanding its current and future atmospheric concentration. Furthermore, for both ozone depleting substances (ODSs) and greenhouse gases, information on their lifetimes is of paramount importance for obtaining future estimates for ozone depletion and climate forcing. The 'Lifetimes of Stratospheric Ozone-Depleting Substances, Their Replacements, and Related Species', under the World Climate Research Programme/Stratospheric Processes And their Role in Climate project, was completed in August 2013. The goal was to estimate both lifetimes and uncertainties. In this presentation we will provide: 1) an overview of key aspects of the definitions of lifetimes, 2) discuss the extensively revised photochemical values and uncertainties for obtaining lifetimes, 3) show new observational and 4) modeling estimates of lifetimes, and finally, 5) show new recommendations for the steady-state atmospheric lifetimes of 27 long-lived species. New findings include: * New chemical kinetic and photochemical information on the uncertainties associated with the Lyman-a absorption cross-sections, and revisions of absorption cross-section parameterizations for several chlorofluorocarbons. * State-of-the-art chemistry-climate models (CCMs) were used to estimate lifetimes over the course of the 21st century. Projected increases of the Brewer-Dobson circulation suggest that lifetimes should be shorter during the 21st century. However, the recovery of ozone in the CCMs shows that the photolysis of many species will decline, yielding only small changes in lifetimes of most species * The CFC-11 recommended lifetime increases to 52 years from the WMO (2011) value of 45 years. The most likely range is narrowed to 43-67 years. * The 44 year steady-state lifetime of CCl4 due to atmospheric loss determined in this report is substantially longer than the 35 years from WMO (2011). However, inclusion of the land and ocean

  10. On the role of atmosphere-ocean interactions in the expected long-term changes of the Earth's ozone layer caused by greenhouse gases

    NASA Astrophysics Data System (ADS)

    Zadorozhny, Alexander; Dyominov, Igor

    It is well known that anthropogenic emissions of greenhouse gases into the atmosphere produce a global warming of the troposphere and a global cooling of the stratosphere. The expected stratospheric cooling essentially influences the ozone layer via increased polar stratospheric cloud formation and via temperature dependences of the gas phase reaction rates. One more mechanism of how greenhouse gases influences the ozone layer is enhanced water evaporation from the oceans into the atmosphere because of increasing temperatures of the ocean surface due to greenhouse effect. The subject of this paper is a study of the influence of anthropogenic pollution of the atmosphere by the greenhouse gases CO2, CH4, N2O and ozone-depleting chlorine and bromine compounds on the expected long-term changes of the ozone layer with taking into account an increase of water vapour content in the atmosphere due to greenhouse effect. The study based on 2-D zonally averaged interactive dynamical radiative-photochemical model of the troposphere and stratosphere. The model allows to self-consistently calculating diabatic circulation, temperature, gaseous composition of the troposphere and stratosphere at latitudes from the South to North Poles, as well as distribution of sulphate aerosol particles and polar stratospheric clouds of two types. It was supposed in the model that an increase of the ocean surface temperature caused by greenhouse effect is similar to calculated increase of atmospheric surface temperature. Evaporation rate from the ocean surface was computed in dependence of latitude. The model time-dependent runs were made for the period from 1975 to 2100 using two IPCC scenarios depicting maximum and average expected increases of greenhouse gases in the atmosphere. The model calculations show that anthropogenic increasing of water vapour abundance in the atmosphere due to heating of the ocean surface caused by greenhouse effect gives a sensible contribution to the expected ozone

  11. Linkages Between Ozone-depleting Substances, Tropospheric Oxidation and Aerosols

    NASA Technical Reports Server (NTRS)

    Voulgarakis, A.; Shindell, D. T.; Faluvegi, G.

    2013-01-01

    Coupling between the stratosphere and the troposphere allows changes in stratospheric ozone abundances to affect tropospheric chemistry. Large-scale effects from such changes on chemically produced tropospheric aerosols have not been systematically examined in past studies. We use a composition-climate model to investigate potential past and future impacts of changes in stratospheric ozone depleting substances (ODS) on tropospheric oxidants and sulfate aerosols. In most experiments, we find significant responses in tropospheric photolysis and oxidants, with small but significant effects on methane radiative forcing. The response of sulfate aerosols is sizeable when examining the effect of increasing future nitrous oxide (N2O) emissions. We also find that without the regulation of chlorofluorocarbons (CFCs) through the Montreal Protocol, sulfate aerosols could have increased by 2050 by a comparable amount to the decreases predicted due to relatively stringent sulfur emissions controls. The individual historical radiative forcings of CFCs and N2O through their indirect effects on methane (-22.6mW/sq. m for CFCs and -6.7mW/sq. m for N2O) and sulfate aerosols (-3.0mW/sq. m for CFCs and +6.5mW/sq. m for N2O when considering the direct aerosol effect) discussed here are non-negligible when compared to known historical ODS forcing. Our results stress the importance of accounting for stratosphere-troposphere, gas-aerosol and composition-climate interactions when investigating the effects of changing emissions on atmospheric composition and climate.

  12. Acid rain, ozone depletion, and the climate response to pulsed Siberian Traps magmatism

    NASA Astrophysics Data System (ADS)

    Black, B. A.; Lamarque, J.; Shields, C. A.; Elkins-Tanton, L. T.; Kiehl, J. T.

    2013-12-01

    The Siberian Traps flood basalts have been invoked as a trigger for the catastrophic end-Permian mass extinction. Widespread aberrant plant remains across the Permian-Triassic boundary provide evidence that atmospheric stress contributed to the collapse in terrestrial diversity. Here, we use recent detailed estimates of magmatic degassing from the Siberian Traps to complete the first 3-D global modeling of atmospheric chemistry during eruption of a large igneous province. We also explore the effects of volcanic gases on climate. Our results show that both strongly acidic rain and global ozone collapse are possible transient consequences of episodic pyroclastic volcanism and heating of volatile-rich Siberian country rocks. We suggest that in conjunction with abrupt warming from greenhouse gas emissions, these repeated, rapidly applied atmospheric stresses directly linked Siberian magmatism to end-Permian ecological failure on land. Our comprehensive modeling describes the global distribution and severity of acid rain and ozone depletion, providing testable predictions for the geography of end-Permian environmental proxies.

  13. Ozone depletion and UVB radiation: impact on plant DNA damage in southern South America.

    PubMed

    Rousseaux, M C; Ballaré, C L; Giordano, C V; Scopel, A L; Zima, A M; Szwarcberg-Bracchitta, M; Searles, P S; Caldwell, M M; Díaz, S B

    1999-12-21

    The primary motivation behind the considerable effort in studying stratospheric ozone depletion is the potential for biological consequences of increased solar UVB (280-315 nm) radiation. Yet, direct links between ozone depletion and biological impacts have been established only for organisms of Antarctic waters under the influence of the ozone "hole;" no direct evidence exists that ozone-related variations in UVB affect ecosystems of temperate latitudes. Indeed, calculations based on laboratory studies with plants suggest that the biological impact of ozone depletion (measured by the formation of cyclobutane pyrimidine dimers in DNA) is likely to be less marked than previously thought, because UVA quanta (315-400 nm) may also cause significant damage, and UVA is unaffected by ozone depletion. Herein, we show that the temperate ecosystems of southern South America have been subjected to increasingly high levels of ozone depletion during the last decade. We found that in the spring of 1997, despite frequent cloud cover, the passages of the ozone hole over Tierra del Fuego (55 degrees S) caused concomitant increases in solar UV and that the enhanced ground-level UV led to significant increases in DNA damage in the native plant Gunnera magellanica. The fluctuations in solar UV explained a large proportion of the variation in DNA damage (up to 68%), particularly when the solar UV was weighted for biological effectiveness according to action spectra that assume a sharp decline in quantum efficiency with increasing wavelength from the UVB into the UVA regions of the spectrum.

  14. Ozone Depletion in the Arctic Lower Stratosphere; Timing and Impacts on the Polar Vortex.

    NASA Astrophysics Data System (ADS)

    Rae, Cameron; Pyle, John

    2017-04-01

    There a strong link between ozone depletion in the Antarctic lower stratosphere and the strength/duration of the southern hemisphere polar vortex. Ozone depletion arising from enhanced levels of ODS in the lower stratosphere during the last few decades of the 20th century has been accompanied by a delay in the final warming date in the southern hemisphere. The delay in final warming is associated with anomalous tropospheric conditions. The relationship in the Arctic, however, is less clear as the northern hemisphere experiences relatively less intense ozone destruction in the Arctic lower stratosphere and the polar vortex is generally less stable. This study investigates the impacts of imposed lower stratospheric ozone depletion on the evolution of the polar vortex, particularly in the late-spring towards the end of its lifetime. A perpetual-year integration is compared with a series of near-identical seasonal integrations which differ only by an imposed artificial ozone depletion event, occurring a fixed number of days before the polar vortex final warming date each year. Any differences between the seasonal forecasts and perpetual year simulation are due to the timely occurrence of a strong ozone depletion event in the late-spring Arctic polar vortex. This ensemble of seasonal forecasts demonstrates the impacts that a strong ozone depletion event in the Arctic lower stratosphere will have on the evolution of the polar vortex, and highlights tropospheric impacts associated with this phenomenon.

  15. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing

    PubMed Central

    Marshall, John; Armour, Kyle C.; Scott, Jeffery R.; Kostov, Yavor; Hausmann, Ute; Ferreira, David; Shepherd, Theodore G.; Bitz, Cecilia M.

    2014-01-01

    In recent decades, the Arctic has been warming and sea ice disappearing. By contrast, the Southern Ocean around Antarctica has been (mainly) cooling and sea-ice extent growing. We argue here that interhemispheric asymmetries in the mean ocean circulation, with sinking in the northern North Atlantic and upwelling around Antarctica, strongly influence the sea-surface temperature (SST) response to anthropogenic greenhouse gas (GHG) forcing, accelerating warming in the Arctic while delaying it in the Antarctic. Furthermore, while the amplitude of GHG forcing has been similar at the poles, significant ozone depletion only occurs over Antarctica. We suggest that the initial response of SST around Antarctica to ozone depletion is one of cooling and only later adds to the GHG-induced warming trend as upwelling of sub-surface warm water associated with stronger surface westerlies impacts surface properties. We organize our discussion around ‘climate response functions’ (CRFs), i.e. the response of the climate to ‘step’ changes in anthropogenic forcing in which GHG and/or ozone-hole forcing is abruptly turned on and the transient response of the climate revealed and studied. Convolutions of known or postulated GHG and ozone-hole forcing functions with their respective CRFs then yield the transient forced SST response (implied by linear response theory), providing a context for discussion of the differing warming/cooling trends in the Arctic and Antarctic. We speculate that the period through which we are now passing may be one in which the delayed warming of SST associated with GHG forcing around Antarctica is largely cancelled by the cooling effects associated with the ozone hole. By mid-century, however, ozone-hole effects may instead be adding to GHG warming around Antarctica but with diminished amplitude as the ozone hole heals. The Arctic, meanwhile, responding to GHG forcing but in a manner amplified by ocean heat transport, may continue to warm at an

  16. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing.

    PubMed

    Marshall, John; Armour, Kyle C; Scott, Jeffery R; Kostov, Yavor; Hausmann, Ute; Ferreira, David; Shepherd, Theodore G; Bitz, Cecilia M

    2014-07-13

    In recent decades, the Arctic has been warming and sea ice disappearing. By contrast, the Southern Ocean around Antarctica has been (mainly) cooling and sea-ice extent growing. We argue here that interhemispheric asymmetries in the mean ocean circulation, with sinking in the northern North Atlantic and upwelling around Antarctica, strongly influence the sea-surface temperature (SST) response to anthropogenic greenhouse gas (GHG) forcing, accelerating warming in the Arctic while delaying it in the Antarctic. Furthermore, while the amplitude of GHG forcing has been similar at the poles, significant ozone depletion only occurs over Antarctica. We suggest that the initial response of SST around Antarctica to ozone depletion is one of cooling and only later adds to the GHG-induced warming trend as upwelling of sub-surface warm water associated with stronger surface westerlies impacts surface properties. We organize our discussion around 'climate response functions' (CRFs), i.e. the response of the climate to 'step' changes in anthropogenic forcing in which GHG and/or ozone-hole forcing is abruptly turned on and the transient response of the climate revealed and studied. Convolutions of known or postulated GHG and ozone-hole forcing functions with their respective CRFs then yield the transient forced SST response (implied by linear response theory), providing a context for discussion of the differing warming/cooling trends in the Arctic and Antarctic. We speculate that the period through which we are now passing may be one in which the delayed warming of SST associated with GHG forcing around Antarctica is largely cancelled by the cooling effects associated with the ozone hole. By mid-century, however, ozone-hole effects may instead be adding to GHG warming around Antarctica but with diminished amplitude as the ozone hole heals. The Arctic, meanwhile, responding to GHG forcing but in a manner amplified by ocean heat transport, may continue to warm at an accelerating rate.

  17. Changes in the solar forced tides caused by stratospheric ozone depletion

    SciTech Connect

    Ross, M.N.; Walterscheid, R.L.

    1991-03-01

    Depletion of stratospheric ozone by anthropogenic trace gases reduces the thermal forcing of the solar-driven atmospheric tides. The authors examine changes that have occurred in the diurnal and semidiurnal upward propagating tides since the onset of stratospheric ozone depletion. Estimated reductions in tide amplitudes since circa 1960 vary among the different modes but are generally less than about 10%. The most accurate measure of tidal strength for the main symmetric semidiurnal mode, the tropical semidiurnal surface pressure oscillation, has decreased about 3% since the beginning of ozone depletion, an amount that might be detected in the barometric record. Reductions in upper atmospheric tidal momentum fluxes are generally less then about 20%. The amplitudes of the solar forced tides will continue to decrease as ozone depletion continues.

  18. PRN 92-2: Permissible label claims regarding ozone depleting substances

    EPA Pesticide Factsheets

    This notice describes EPA's policy for certain chlorofluorocarbon-related labeling claims on pesticide aerosol products. Under this policy, true claims that a product does not contain CFCs or other ozone-depleting substances are permitted on labels.

  19. Surface ozone depletion in Arctic spring sustained by bromine reactions on aerosols

    NASA Astrophysics Data System (ADS)

    Fan, Song-Miao; Jacob, Daniel J.

    1992-10-01

    NEAR-TOTAL depletion of the ozone in surface air is often observed in the Arctic spring, coincident with high atmospheric concentrations of inorganic bromine. A mechanism based on known aqueous-phase chemistry is proposed which rapidly converts HBr, HOBr, and BrNO3 back to Br and BrO radicals. This mechanism should be particularly efficient in the presence of the high concentrations of sulphuric acid aerosols observed during ozone depletion events.

  20. ENVIRONMENTAL EFFECTS OF OZONE DEPLETION AND ITS INTERACTIONS WITH CLIMATE CHANGE: PROGRESS REPORT 2003

    EPA Science Inventory

    The measures needed for the protection of the Earth's ozone layer are decided regularly by the Parties to the Montreal Protocol. A section of this progress report focuses on the interactive effects of climate change and ozone depletion on biogeochemical cycles.

  1. ENVIRONMENTAL EFFECTS OF OZONE DEPLETION AND ITS INTERACTIONS WITH CLIMATE CHANGE: PROGRESS REPORT 2003

    EPA Science Inventory

    The measures needed for the protection of the Earth's ozone layer are decided regularly by the Parties to the Montreal Protocol. A section of this progress report focuses on the interactive effects of climate change and ozone depletion on biogeochemical cycles.

  2. Ozone Depletion Potential of CH3Br. Appendix H

    NASA Technical Reports Server (NTRS)

    Ko, Malcolm K. W.; Sze, Nien Dak; Scott, Courtney; Rodriguez, Jose M.; Weisenstein, Debra K.; Sander, Stanley P.

    1998-01-01

    The ozone depletion potential (ODP) of methyl bromide (CH3Br) can be determined by combining the model-calculated bromine efficiency factor (BEF) for CH3Br and its atmospheric lifetime. This paper examines how changes in several key kinetic data affect BEF. The key reactions highlighted in this study include the reaction of BrO + HO2, the absorption cross section of HOBr, the absorption cross section and the photolysis products of BrONO2, and the heterogeneous conversion of BrONO2 to HOBr and HNO3 on aerosol particles. By combining the calculated BEF with the latest estimate of 0.7 year for the atmospheric lifetime of CH3Br, the likely value of ODP for CH3Br is 0.39. The model-calculated concentration of HBr (approx. 0.3 pptv) in the lower stratosphere is substantially smaller than the reported measured value of about 1 pptv. Recent publications suggested models can reproduce the measured value if one assumes a yield for HBr from the reaction of BrO + OH or from the reaction of BrO + HO2. Although the evaluation concluded any substantial yield of HBr from BrO + HO2 is unlikely, for completeness, we calculate the effects of these assumed yields on BEF for CH3Br. Our calculations show that the effects are minimal: practically no impact for an assumed 1.3% yield of HBr from BrO + OH and 10% smaller for an assumed 0.6% yield from BrO + HO2.

  3. Ozone Depletion Potential of CH3Br. Appendix H

    NASA Technical Reports Server (NTRS)

    Ko, Malcolm K. W.; Sze, Nien Dak; Scott, Courtney; Rodriguez, Jose M.; Weisenstein, Debra K.; Sander, Stanley P.

    1998-01-01

    The ozone depletion potential (ODP) of methyl bromide (CH3Br) can be determined by combining the model-calculated bromine efficiency factor (BEF) for CH3Br and its atmospheric lifetime. This paper examines how changes in several key kinetic data affect BEF. The key reactions highlighted in this study include the reaction of BrO + HO2, the absorption cross section of HOBr, the absorption cross section and the photolysis products of BrONO2, and the heterogeneous conversion of BrONO2 to HOBr and HNO3 on aerosol particles. By combining the calculated BEF with the latest estimate of 0.7 year for the atmospheric lifetime of CH3Br, the likely value of ODP for CH3Br is 0.39. The model-calculated concentration of HBr (approx. 0.3 pptv) in the lower stratosphere is substantially smaller than the reported measured value of about 1 pptv. Recent publications suggested models can reproduce the measured value if one assumes a yield for HBr from the reaction of BrO + OH or from the reaction of BrO + HO2. Although the evaluation concluded any substantial yield of HBr from BrO + HO2 is unlikely, for completeness, we calculate the effects of these assumed yields on BEF for CH3Br. Our calculations show that the effects are minimal: practically no impact for an assumed 1.3% yield of HBr from BrO + OH and 10% smaller for an assumed 0.6% yield from BrO + HO2.

  4. Children's Use of Metaphors in Relation To Their Mental Models: The Case of the Ozone Layer and Its Depletion.

    ERIC Educational Resources Information Center

    Christidou, Vasilia; Koulaidis, Vasilis; Christidis, Theodor

    1997-01-01

    Examines the relationship between children's use of metaphors and their mental models concerning the ozone layer and ozone layer depletion. Results indicate that the way children represent the role and depletion of ozone is strongly correlated with the types of metaphors they use while constructing and/or articulating their models. Also discusses…

  5. Children's Use of Metaphors in Relation To Their Mental Models: The Case of the Ozone Layer and Its Depletion.

    ERIC Educational Resources Information Center

    Christidou, Vasilia; Koulaidis, Vasilis; Christidis, Theodor

    1997-01-01

    Examines the relationship between children's use of metaphors and their mental models concerning the ozone layer and ozone layer depletion. Results indicate that the way children represent the role and depletion of ozone is strongly correlated with the types of metaphors they use while constructing and/or articulating their models. Also discusses…

  6. Greenhouse gases and recovery of the Earth’s ozone layer

    NASA Astrophysics Data System (ADS)

    Dyominov, Igor G.; Zadorozhny, Alexander M.

    A numerical 2-D zonally averaged dynamical radiative-photochemical model of the ozonosphere including aerosol physics is used to examine the role of the greenhouse gases CO 2, CH 4, and N 2O in the recovery of the Earth's ozone layer after reduction of anthropogenic discharges of chlorine and bromine compounds into the atmosphere. A weakness in efficiencies of all catalytic cycles of the ozone destruction due to cooling of the stratosphere caused by greenhouse gases is shown to be a dominant mechanism of the impact of the greenhouse gases on the ozone layer. Numerical experiments show that the total ozone changes caused by greenhouse gases will be comparable in absolute value with the changes due to chlorine and bromine species in the middle of the 21st century. Continuous anthropogenic growth of CO 2 will lead to a significantly faster recovery of the ozone layer. In this case, the global total ozone in the latitude range from 60°S to 60°N will reach its undisturbed level of 1980 by about 2040. If the CO 2 growth stops, the global total ozone will reach this level only by the end of the century.

  7. Simulating halogen radical chemistry and Br propagation during ozone depletion events in Barrow, Alaska

    NASA Astrophysics Data System (ADS)

    Stephens, C. R.; Shepson, P.; Liao, J.; Huey, L. G.; Apel, E. C.; Cantrell, C. A.; Flocke, F. M.; Fried, A.; Hall, S. R.; Hornbrook, R. S.; Knapp, D. J.; Mauldin, L.; Montzka, D.; Sive, B. C.; Ullman, K.; Weibring, P.; Weinheimer, A. J.

    2012-12-01

    The springtime depletion of tropospheric ozone in the Arctic is believed to be caused by active halogen photochemistry resulting from halogen atom precursors present on snow, ice, or aerosol surfaces. The role of bromine in driving ozone depletion events (ODEs) has been generally accepted from numerous field studies that have observed high concentrations of BrO and filterable bromide during this time. The presence of chlorine in the Arctic has been recognized, but much less is known about the role of chlorine radicals in ozone depletion chemistry. Iodine monoxide has yet to be successfully detected in the High Arctic, although there have been indications of active iodine chemistry through observed enhancements in filterable iodide and probable detection of IO. Despite decades of research, significant uncertainty remains regarding the chemical mechanisms associated with the bromine-catalyzed depletion of ozone, as well as the complex interactions that occur in the polar boundary layer due to halogen chemistry. We developed a 0-D, multiphase, photochemical model to investigate the chemistry of bromine, chlorine and iodine relating to the occurrence of ODEs. Our model is highly constrained to time-varying observations of O3, Cl2, Br2, OVOCs, and VOCs from the 2009 Ocean-Atmosphere-Sea Ice-Snowpack (OASIS) campaign in Barrow, Alaska. We investigated a 7-day period in late March to determine the contribution of Br, Cl, and potential contribution of I to ozone depletion and the interactions occurring between these three halogens under the chemical conditions observed. We find that while Br accounts for the majority of ozone depletion, iodine is more efficient on a per molecule basis and that both chlorine and iodine serve to enhance the Br-induced depletion of ozone through synergistic effects. Though Cl does not directly contribute significantly to ozone depletion, chlorine impacts bromine chemistry through ClO and RO2, which in turn impact BrOx propagation, and by

  8. Guidance on the DOE facility phaseout of ozone-depleting substances

    SciTech Connect

    1995-10-01

    The phaseout of ozone-depleting substances substantially affects Department of Energy (DOE) operations associated with refrigeration and air conditioning, fire protection, and solvent usage throughout the complex. Among the more important requirements facing the Department in this area are those associated with Executive Order 12843 (``Procurement Requirements and Policies for Federal Agencies for Ozone-Depleting Substances``), the Environmental Protection Agency (EPA) regulations that implement (``Federal Procurement``) of the Clean Air Act, and an interim rule (``Federal Acquisition Regulation; Ozone Executive Order``) that amends the Federal Acquisition Regulation (FAR). The first two directives require Federal agencies to significantly reduce use, where practicable, of ozone-depleting substances, through cost-effective procurement practices and through the substitution of safe alternative substances, and to provide leadership in their phaseout.

  9. Dependence of model-simulated response to ozone depletion on stratospheric polar vortex climatology

    NASA Astrophysics Data System (ADS)

    Lin, Pu; Paynter, David; Polvani, Lorenzo; Correa, Gustavo J. P.; Ming, Yi; Ramaswamy, V.

    2017-06-01

    We contrast the responses to ozone depletion in two climate models: Community Atmospheric Model version 3 (CAM3) and Geophysical Fuild Dynamics Laboratory (GFDL) AM3. Although both models are forced with identical ozone concentration changes, the stratospheric cooling simulated in CAM3 is 30% stronger than in AM3 in annual mean, and twice as strong in December. We find that this difference originates from the dynamical response to ozone depletion, and its strength can be linked to the timing of the climatological springtime polar vortex breakdown. This mechanism is further supported by a variant of the AM3 simulation in which the southern stratospheric zonal wind climatology is nudged to be CAM3-like. Given that the delayed breakdown of the southern polar vortex is a common bias among many climate models, previous model-based assessments of the forced responses to ozone depletion may have been somewhat overestimated.

  10. The potential for ozone depletion in the arctic polar stratosphere.

    PubMed

    Brune, W H; Anderson, J G; Toohey, D W; Fahey, D W; Kawa, S R; Jones, R L; McKenna, D S; Poole, L R

    1991-05-31

    The nature of the Arctic polar stratosphere is observed to be similar in many respects to that of the Antarctic polar stratosphere, where an ozone hole has been identified. Most of the available chlorine (HCl and ClONO(2)) was converted by reactions on polar stratospheric clouds to reactive ClO and Cl(2)O(2) throughout the Arctic polar vortex before midwinter. Reactive nitrogen was converted to HNO(3), and some, with spatial inhomogeneity, fell out of the stratosphere. These chemical changes ensured characteristic ozone losses of 10 to 15% at altitudes inside the polar vortex where polar stratospheric clouds had occurred. These local losses can translate into 5 to 8% losses in the vertical column abundance of ozone. As the amount of stratospheric chlorine inevitably increases by 50% over the next two decades, ozone losses recognizable as an ozone hole may well appear.

  11. The potential for ozone depletion in the Arctic polar stratosphere

    NASA Technical Reports Server (NTRS)

    Brune, W. H.; Anderson, J. G.; Toohey, D. W.; Fahey, D. W.; Kawa, S. R.; Poole, L. R.

    1991-01-01

    The nature of the Arctic polar stratosphere is observed to be similar in many respects to that of the Antarctic polar stratosphere, where an ozone hole has been identified. Most of the available chlorine (CHl and ClONO2) was converted by reactions on polar stratospheric clouds to reactive ClO and Cl2O2 thoroughout the Arctic polar vortex before midwinter. Reactive nitrogen was converted to HNO3, and some, with spatial inhomogeneity, fell out of the stratosphere. These chemical changes ensured characteristic ozone losses of 10 to 15 percent at altitudes inside the polar vortex where polar stratospheric clouds had occurred. These local losses can translate into 5 to 8 percent losses in the vertical column abundance of ozone. As the amount of stratospheric chlorine inevitably increases by 50 percent over the next two decades, ozone losses recognizable as an ozone hole may well appear.

  12. Depletions in winter total ozone values over southern England

    NASA Technical Reports Server (NTRS)

    Lapworth, A.

    1994-01-01

    A study has been made of the recently re-evaluated time series of daily total ozone values for the period 1979 to 1992 for southern England. The series consists of measurements made at two stations, Bracknell and Camborne. The series shows a steady decline in ozone values in the spring months over the period, and this is consistent with data from an earlier decade that has been published but not re-evaluated. Of exceptional note is the monthly mean for January 1992 which was very significantly reduced from the normal value, and was the lowest so far measured for this month. This winter was also noteworthy for a prolonged period during which a blocking anticyclone dominated the region, and the possibility existed that this was related to the ozone anomaly. It was possible to determine whether the origin of the low ozone value lay in ascending stratospheric motions. A linear regression analysis of ozone value deviation against 100hPa temperature deviations was used to reduce ozone values to those expected in the absence of high pressure. The assumption was made that the normal regression relation was not affected by atmospheric anomalies during the winter. This showed that vertical motions in the stratosphere only accounted for part of the ozone anomaly and that the main cause of the ozone deficit lay either in a reduced stratospheric circulation to which the anticyclone may be related or in chemical effects in the reduced stratospheric temperatures above the high pressure area. A study of the ozone time series adjusted to remove variations correlated with meteorological quantities, showed that during the period since 1979, one other winter, that of 1982/3, showed a similar although less well defined deficit in total ozone values.

  13. Changes in tropospheric composition and air quality due to stratospheric ozone depletion.

    PubMed

    Solomon, Keith R; Tang, Xiaoyan; Wilson, Stephen R; Zanis, Prodromos; Bais, Alkiviadis F

    2003-01-01

    Increased UV-B through stratospheric ozone depletion leads to an increased chemical activity in the lower atmosphere (the troposphere). The effect of stratospheric ozone depletion on tropospheric ozone is small (though significant) compared to the ozone generated anthropogenically in areas already experiencing air pollution. Modeling and experimental studies suggest that the impacts of stratospheric ozone depletion on tropospheric ozone are different at different altitudes and for different chemical regimes. As a result the increase in ozone due to stratospheric ozone depletion may be greater in polluted regions. Attributable effects on concentrations are expected only in regions where local emissions make minor contributions. The vertical distribution of NOx (NO + NO2), the emission of volatile organic compounds and the abundance of water vapor, are important influencing factors. The long-term nature of stratospheric ozone depletion means that even a small increase in tropospheric ozone concentration can have a significant impact on human health and the environment. Trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA) are produced by the atmospheric degradation of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). TFA has been measured in rain, rivers, lakes, and oceans, the ultimate sink for these and related compounds. Significant anthropogenic sources of TFA other than degradation HCFCs and HFCs have been identified. Toxicity tests under field conditions indicate that the concentrations of TFA and CDFA currently produced by the atmospheric degradation of HFCs and HCFCs do not present a risk to human health and the environment. The impact of the interaction between ozone depletion and future climate change is complex and a significant area of current research. For air quality and tropospheric composition, a range of physical parameters such as temperature, cloudiness and atmospheric transport will modify the impact of UV-B. Changes in the

  14. 76 FR 78832 - Protection of Stratospheric Ozone: Listing of Substitutes for Ozone-Depleting Substances...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-20

    ... information on SNAP, refer to EPA's Ozone Layer Protection Web site at: www.epa.gov/ozone/snap/index.html... local air quality. International experts came to a similar conclusion in Safeguarding the Ozone Layer... AGENCY 40 CFR Part 82 RIN 2060-AP54 Protection of Stratospheric Ozone: Listing of Substitutes for...

  15. Future chlorine-bromine loading and ozone depletion

    NASA Technical Reports Server (NTRS)

    Prather, Michael J.; Ibrahim, Abdel Moneim; Sasaki, Toru; Stordal, Frode; Visconti, Guido

    1991-01-01

    The prediction of future ozone requires three elements: (1) a scenario for the net emissions of chemically and radiatively active trace gases from the land and oceans; (2) a global atmospheric model that projects the accumulation of these gases; and (3) a chemical transport model that describes the distribution of ozone for a prescribed atmospheric composition and climate. This chapter, of necessity, presents models for all three elements and focuses on the following: (1) atmospheric abundance of chlorine and bromine in the form of halocarbons; and (2) the associated perturbations to stratospheric ozone.

  16. Evolution of ozone depletion on Antarctic and sub-Antarctic regions (1979-2012)

    NASA Astrophysics Data System (ADS)

    Diaz, S. B.; Paladini, A. A.; Deferrari, G. A.; Vrsalovic, J.

    2013-08-01

    At the middle eighties, strong stratospheric ozone depletion during spring was discovered over Antarctica. Since then, the scientific community has put large efforts in performing studies directed to evaluate the magnitude and consequences of this depletion and to take the necessary measures to revert the situation to the scenarios before 1970. In 1987, the Montreal Protocol established a list of ozone depleting products and faced out policies. As consequence of these restrictions on ozone depleting substances, the ozone layer should start to recover in the 21st century. In order to study the evolution of the Antarctic ozone depletion, we analyzed the ozone hole area and mass deficit and seasonal total ozone column (TOC) minimum. We also performed a seasonal and bi-monthly analysis for TOC time series (1979-2012), at twenty Antarctic and Sub-Antarctic stations. The number of days inside the vortex (TOC below 220DU) per season (September-December) and for September-October and November-December were analyzed, fitting the time series with a second degree polynomial According to this study, ozone hole area would have peaked between 2001 and 2002 (R=0.91, p<0.01), while the minimum TOC would have occurred between 2000 and 2001(R=0.91, p<0.01). Mass deficit is only provided since 2005 and it showed a decrease since then, although ot statistically significant as consequence of the short time series. From the 20 analyzed stations, 80% showed that the number of days per season inside the vortex peaked between 2000 and 2003 and for 55% of the stations the number of days inside the vortex for September-October peaked between 1999 and 2004.

  17. Ozone depletion and UVB radiation: Impact on plant DNA damage in southern South America

    PubMed Central

    Rousseaux, M. Cecilia; Ballaré, Carlos L.; Giordano, Carla V.; Scopel, Ana L.; Zima, Ana M.; Szwarcberg-Bracchitta, Mariela; Searles, Peter S.; Caldwell, Martyn M.; Díaz, Susana B.

    1999-01-01

    The primary motivation behind the considerable effort in studying stratospheric ozone depletion is the potential for biological consequences of increased solar UVB (280–315 nm) radiation. Yet, direct links between ozone depletion and biological impacts have been established only for organisms of Antarctic waters under the influence of the ozone “hole;” no direct evidence exists that ozone-related variations in UVB affect ecosystems of temperate latitudes. Indeed, calculations based on laboratory studies with plants suggest that the biological impact of ozone depletion (measured by the formation of cyclobutane pyrimidine dimers in DNA) is likely to be less marked than previously thought, because UVA quanta (315–400 nm) may also cause significant damage, and UVA is unaffected by ozone depletion. Herein, we show that the temperate ecosystems of southern South America have been subjected to increasingly high levels of ozone depletion during the last decade. We found that in the spring of 1997, despite frequent cloud cover, the passages of the ozone hole over Tierra del Fuego (55° S) caused concomitant increases in solar UV and that the enhanced ground-level UV led to significant increases in DNA damage in the native plant Gunnera magellanica. The fluctuations in solar UV explained a large proportion of the variation in DNA damage (up to 68%), particularly when the solar UV was weighted for biological effectiveness according to action spectra that assume a sharp decline in quantum efficiency with increasing wavelength from the UVB into the UVA regions of the spectrum. PMID:10611381

  18. Microphysical Modelling of the 1999-2000 Arctic Winter. 2; Chlorine Activation and Ozone Depletion

    NASA Technical Reports Server (NTRS)

    Drdla, K.; Schoeberl, M. R.; Gore, Warren J. (Technical Monitor)

    2001-01-01

    The effect of a range of assumptions about polar stratospheric clouds (PSCs) on ozone depletion has been assessed using at couple microphysical/photochemical model. The composition of the PSCs was varied (ternary solutions, nitric acid trihydrate, nitric acid dehydrate, or ice), as were parameters that affected the levels of denitrification and dehydration. Ozone depletion was affected by assumptions about PSC freezing because of the variability in resultant nitrification chlorine activation in all scenarios was similar despite the range of assumed PSC compositions. Vortex-average ozone loss exceeded 40% in the lower stratosphere for simulations without nitrification an additional ozone loss of 15-20% was possible in scenarios where vortex-average nitrification reached 60%. Ozone loss intensifies non-linearly with enhanced nitrification in air parcels with 90% nitrification 40% ozone loss in mid-April can be attributed to nitrification alone. However, these effects are sensitive to the stability of the vortex in springtime: nitrification only began to influence ozone depletion in mid-March.

  19. Microphysical Modelling of the 1999-2000 Arctic Winter. 2; Chlorine Activation and Ozone Depletion

    NASA Technical Reports Server (NTRS)

    Drdla, K.; Schoeberl, M. R.; Gore, Warren J. (Technical Monitor)

    2001-01-01

    The effect of a range of assumptions about polar stratospheric clouds (PSCs) on ozone depletion has been assessed using at couple microphysical/photochemical model. The composition of the PSCs was varied (ternary solutions, nitric acid trihydrate, nitric acid dehydrate, or ice), as were parameters that affected the levels of denitrification and dehydration. Ozone depletion was affected by assumptions about PSC freezing because of the variability in resultant nitrification chlorine activation in all scenarios was similar despite the range of assumed PSC compositions. Vortex-average ozone loss exceeded 40% in the lower stratosphere for simulations without nitrification an additional ozone loss of 15-20% was possible in scenarios where vortex-average nitrification reached 60%. Ozone loss intensifies non-linearly with enhanced nitrification in air parcels with 90% nitrification 40% ozone loss in mid-April can be attributed to nitrification alone. However, these effects are sensitive to the stability of the vortex in springtime: nitrification only began to influence ozone depletion in mid-March.

  20. Biological UV-doses and the effect of an ozone layer depletion.

    PubMed

    Dahlback, A; Henriksen, T; Larsen, S H; Stamnes, K

    1989-05-01

    Effective UV-doses were calculated based on the integrated product of the biological action spectrum (the one proposed by IEC, which extends to 400 nm, was adopted) and the spectral irradiance. The calculations include absorption and scattering of UV-radiation in the atmosphere, both for normal ozone conditions as well as for a depleted ozone layer. For Scandinavian latitudes the effective annual UV-dose increases by approximately 4% per degrees of latitude towards the Equator. An ozone depletion of one percent increases the annual UV-dose by approximately 1% at 60 degrees N (increases slightly at lower latitudes). A large depletion of 50% over Scandinavia (60 degrees N) would give these countries an effective UV-dose similar to that obtained, with normal ozone conditions, at a latitude of 40 degrees N (California or the Mediterranean countries). The Antarctic ozone hole increases the annual UV-dose by 20 to 25% which is a similar increase as that attained by moving 5 to 6 degrees of latitude nearer the Equator. The annual UV-dose at higher latitudes is mainly determined by the summer values of ozone. Both the ozone values and the effective UV-doses vary from one year to another (within +/- 4%). No positive or negative trend is observed for Scandinavia from 1978 to 1988.

  1. Ozone, Climate, and Global Atmospheric Change.

    ERIC Educational Resources Information Center

    Levine, Joel S.

    1992-01-01

    Presents an overview of global atmospheric problems relating to ozone depletion and global warming. Provides background information on the composition of the earth's atmosphere and origin of atmospheric ozone. Describes causes, effects, and evidence of ozone depletion and the greenhouse effect. A vignette provides a summary of a 1991 assessment of…

  2. Ozone, Climate, and Global Atmospheric Change.

    ERIC Educational Resources Information Center

    Levine, Joel S.

    1992-01-01

    Presents an overview of global atmospheric problems relating to ozone depletion and global warming. Provides background information on the composition of the earth's atmosphere and origin of atmospheric ozone. Describes causes, effects, and evidence of ozone depletion and the greenhouse effect. A vignette provides a summary of a 1991 assessment of…

  3. Teaching about ozone layer depletion in Turkey: pedagogical content knowledge of science teachers.

    PubMed

    Bozkurt, Orçun; Kaya, Osman Nafiz

    2008-04-01

    The purpose of this study was to investigate the pedagogical content knowledge of Prospective Science Teachers (PSTs) on the topic of "ozone layer depletion." In order to explore PSTs' subject matter knowledge on ozone layer depletion, they were given a form of multiple-choice test where they needed to write the reasons behind their answers. This test was completed by 140 PSTs in their final year at the College of Education. Individual interviews were carried out with 42 randomly selected PSTs to determine their pedagogical knowledge about ozone layer depletion. Data were obtained from the study which indicate that the PSTs did not have adequate subject matter and pedagogical knowledge to teach the topic of ozone layer depletion to middle school students. It was also evident that the PSTs held various misconceptions related to ozone layer depletion. PSTs' inadequate pedagogical knowledge was found in the areas of the curriculum, learning difficulties of students, and instructional strategies and activities. This study provides some pedagogical implications for the training of science teachers.

  4. Simulation of Halocarbon Production and Emissions and Effects on Ozone Depletion

    PubMed

    Holmes; Ellis

    1997-09-01

    / This paper describes an integrated model that simulates future halocarbon production/emissions and potential ozone depletion. Applications and historical production levels for various halocarbons are discussed first. A framework is then presented for modeling future halocarbon impacts incorporating differences in underlying demands, applications, regulatory mandates, and environmental characteristics. The model is used to simulate the potential impacts of several prominent issues relating to halocarbon production, regulation, and environmental interactions, notably: changes in agricultural methyl bromide use, increases in effectiveness of bromine for ozone depletion, modifications to the elimination schedule for HCFCs, short-term expansion of CFC demand in low use compliance countries, and delays in Russian Federation compliance. Individually, each issue does not unequivocally represent a significant likely increase in long-term atmospheric halogen loading and stratospheric ozone depletion. In combination, however, these impacts could increase peak halogen concentrations and long-term integral halogen loading, resulting in higher levels of stratospheric ozone depletion and longer exposure to increased levels of UV radiation.KEY WORDS: Halocarbons; Ozone depletion; Montreal Protocol; Integrated assessment

  5. Impact of ozone on quantity and quality of greenhouse-grown potato plants

    SciTech Connect

    Pell, E.J.; Weissberger, W.C.; Speroni, J.J.

    1980-05-01

    The impact of ozone on quality and quantity of greenhouse-grown potatoes was considered. In two experiments conducted in 1977 and 1978, Norland and Kennebec potato plants were grown in a conventional greenhouse. Once every 2 weeks, 10 plants of each cultivar were exposed to 387 ..mu..g/m/sup 3/ (0.20 ppm) ozone for 3 h in a controlled environment chamber. At 120 and 140 days, for Norland and Kennebec, respectively, vines were killed and tubers were harvested. The number and weight of tubers harvested from ozonized plants decreased significantly in both cultivars. Significant decreases in total solids and increases in reducing sugars of tubers from ozone-exposed plants were identified.

  6. Thomas calls stratospheric ozone depletion rate alarming; urges CFC, halon phaseout

    SciTech Connect

    Not Available

    1988-11-01

    US Environmental Protection Agency Administrator Lee M. Thomas on September 28 called for even greater efforts in halting the depletion of stratospheric ozone by asking all nations to ratify the Montreal Protocol and then move toward a complete phaseout of ozone-depleting chlorofluorocarbons (CFCs) and halons. We must go further than a 50-percent reduction in these chemicals in order to stabilize ozone levels. The Protocol has been signed by 45 nations, but still needs ratification by the European nations and the European Economic Community in order to enter into force next January. It is increasingly clear that we as a global environmental community must use the Protocol to go even further to eliminate these chemicals which damage the stratospheric-ozone layer and threaten our future.

  7. Stratospheric ozone depletion and future levels of atmospheric chlorine and bromine

    NASA Technical Reports Server (NTRS)

    Prather, Michael J.; Watson, Robert T.

    1990-01-01

    The rise in atmospheric chlorine levels caused by the emission of chlorofluorocarbons and other halocarbons is thought to be the main cause of the appearance of the Antarctic ozone 'hole' in the late 1970s, and the more modest ozone depletion observed over parts of the Northern Hemisphere. Atmospheric bromine, also associated with halocarbon emissions, is believed to contribute to ozone depletion. Over the next decade, further increases in these compounds are inevitable. Model calculations show that by the end of the next century, atmospheric chlorine and bromine levels may return to those prevalent before the onset of the ozone hole, but only if more stringent regulations are applied to halocarbon production than those currently proposed.

  8. Stratospheric ozone depletion and future levels of atmospheric chlorine and bromine

    NASA Technical Reports Server (NTRS)

    Prather, Michael J.; Watson, Robert T.

    1990-01-01

    The rise in atmospheric chlorine levels caused by the emission of chlorofluorocarbons and other halocarbons is thought to be the main cause of the appearance of the Antarctic ozone 'hole' in the late 1970s, and the more modest ozone depletion observed over parts of the Northern Hemisphere. Atmospheric bromine, also associated with halocarbon emissions, is believed to contribute to ozone depletion. Over the next decade, further increases in these compounds are inevitable. Model calculations show that by the end of the next century, atmospheric chlorine and bromine levels may return to those prevalent before the onset of the ozone hole, but only if more stringent regulations are applied to halocarbon production than those currently proposed.

  9. 75 FR 25799 - Protection of Stratospheric Ozone: Listing of Substitutes for Ozone-Depleting Substances...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-10

    ... the ozone layer. The GWP index is a means of quantifying the potential integrated climate forcing of... AGENCY 40 CFR Part 82 RIN 2060-AP54 Protection of Stratospheric Ozone: Listing of Substitutes for Ozone... 25, 2010 in Washington, DC and further information will be provided on EPA's Stratospheric...

  10. Role of the boundary layer in the occurrence and termination of the tropospheric ozone depletion events in polar spring

    NASA Astrophysics Data System (ADS)

    Cao, Le; Platt, Ulrich; Gutheil, Eva

    2016-05-01

    Tropospheric ozone depletion events (ODEs) in the polar spring are frequently observed in a stable boundary layer condition, and the end of the events occurs when there is a breakup of the boundary layer. In order to improve the understanding of the role of the boundary layer in the ozone depletion event, a one-dimensional model is developed, focusing on the occurrence and the termination period of the ozone depletion episode. A module accounting for the vertical air transport is added to a previous box model, and a first-order parameterization is used for the estimation of the vertical distribution of the turbulent diffusivity. Simulations are performed for different strengths of temperature inversion as well as for different wind speeds. The simulation results suggest that the reactive bromine species released from the underlying surface into the lowest part of the troposphere initially stay in the boundary layer, leading to an increase of the bromine concentration. This bromine accumulation causes the ozone destruction below the top of the boundary layer. After the ozone is totally depleted, if the temperature inversion intensity decreases or the wind speed increases, the severe ozone depletion event tends to transit into a partial ozone depletion event or it recovers to the normal ozone background level of 30-40 ppb. This recovery process takes about 2 h. Due to the presence of high-level HBr left from the initial occurrence of ODEs, the complete removal of ozone in the boundary layer is achieved a few days after the first termination of ODE. The time required for the recurrence of the ozone depletion in a 1000 m boundary layer is approximately 5 days, while the initial occurrence of the complete ozone consumption takes 15 days. The present model is suitable to clarify the reason for both the start and the termination of the severe ozone depletion as well as the partial ozone depletion in the observations.

  11. Ultraviolet radiation in the Arctic - The impact of potential ozone depletions and cloud effects

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee; Stamnes, Knut

    1992-01-01

    The combined effects of ozone depletions/redistributions and particulate clouds on atmospheric cheating/photolysis rates and UV radiation reaching the biosphere are investigated by means of an atmospheric radiation model. Consideration is given to four types of particulate clouds prevalent in the summertime Arctic: stratospheric aerosols, tropospheric aerosols (Arctic haze), cirrus clouds, and stratus clouds. The effects of ozone depletion and vertical redistributions of ozone are also examined. Stratus clouds are found to provide significant protection from UV radiation exposure, but while stratospheric aerosols imply increased UVB exposure, Arctic haze results in a decrease. A redistribution of ozone from the stratosphere to the troposphere tends to decrease UV exposure, but for low solar elevations an increase may occur. A 20-percent ozone depletion leads to about 0.4 K/d cooling in the lower stratosphere, while redistribution of ozone from the stratosphere to the troposphere implies a warming of about 0.015 K/d in the upper troposphere.

  12. Toward Describing the Effects of Ozone Depletion on Marine Primary Productivity and Carbon Cycling

    NASA Technical Reports Server (NTRS)

    Cullen, John J.

    1995-01-01

    This project was aimed at improved predictions of the effects of UVB and ozone depletion on marine primary productivity and carbon flux. A principal objective was to incorporate a new analytical description of photosynthesis as a function of UV and photosynthetically available radiation (Cullen et. al., Science 258:646) into a general oceanographic model. We made significant progress: new insights into the kinetics of photoinhibition were used in the analysis of experiments on Antarctic phytoplankton to generate a general model of UV-induced photoinhibition under the influence of ozone depletion and vertical mixing. The way has been paved for general models on a global scale.

  13. Synchronous volcanic eruptions and abrupt climate change ∼17.7 ka plausibly linked by stratospheric ozone depletion

    PubMed Central

    McConnell, Joseph R.; Burke, Andrea; Dunbar, Nelia W.; Köhler, Peter; Thomas, Jennie L.; Chellman, Nathan J.; Maselli, Olivia J.; Sigl, Michael; Adkins, Jess F.; Baggenstos, Daniel; Burkhart, John F.; Brook, Edward J.; Buizert, Christo; Cole-Dai, Jihong; Fudge, T. J.; Knorr, Gregor; Graf, Hans-F.; Grieman, Mackenzie M.; Iverson, Nels; McGwire, Kenneth C.; Mulvaney, Robert; Paris, Guillaume; Rhodes, Rachael H.; Saltzman, Eric S.; Steffensen, Jørgen Peder; Taylor, Kendrick C.; Winckler, Gisela

    2017-01-01

    Glacial-state greenhouse gas concentrations and Southern Hemisphere climate conditions persisted until ∼17.7 ka, when a nearly synchronous acceleration in deglaciation was recorded in paleoclimate proxies in large parts of the Southern Hemisphere, with many changes ascribed to a sudden poleward shift in the Southern Hemisphere westerlies and subsequent climate impacts. We used high-resolution chemical measurements in the West Antarctic Ice Sheet Divide, Byrd, and other ice cores to document a unique, ∼192-y series of halogen-rich volcanic eruptions exactly at the start of accelerated deglaciation, with tephra identifying the nearby Mount Takahe volcano as the source. Extensive fallout from these massive eruptions has been found >2,800 km from Mount Takahe. Sulfur isotope anomalies and marked decreases in ice core bromine consistent with increased surface UV radiation indicate that the eruptions led to stratospheric ozone depletion. Rather than a highly improbable coincidence, circulation and climate changes extending from the Antarctic Peninsula to the subtropics—similar to those associated with modern stratospheric ozone depletion over Antarctica—plausibly link the Mount Takahe eruptions to the onset of accelerated Southern Hemisphere deglaciation ∼17.7 ka. PMID:28874529

  14. Synchronous volcanic eruptions and abrupt climate change ∼17.7 ka plausibly linked by stratospheric ozone depletion.

    PubMed

    McConnell, Joseph R; Burke, Andrea; Dunbar, Nelia W; Köhler, Peter; Thomas, Jennie L; Arienzo, Monica M; Chellman, Nathan J; Maselli, Olivia J; Sigl, Michael; Adkins, Jess F; Baggenstos, Daniel; Burkhart, John F; Brook, Edward J; Buizert, Christo; Cole-Dai, Jihong; Fudge, T J; Knorr, Gregor; Graf, Hans-F; Grieman, Mackenzie M; Iverson, Nels; McGwire, Kenneth C; Mulvaney, Robert; Paris, Guillaume; Rhodes, Rachael H; Saltzman, Eric S; Severinghaus, Jeffrey P; Steffensen, Jørgen Peder; Taylor, Kendrick C; Winckler, Gisela

    2017-09-19

    Glacial-state greenhouse gas concentrations and Southern Hemisphere climate conditions persisted until ∼17.7 ka, when a nearly synchronous acceleration in deglaciation was recorded in paleoclimate proxies in large parts of the Southern Hemisphere, with many changes ascribed to a sudden poleward shift in the Southern Hemisphere westerlies and subsequent climate impacts. We used high-resolution chemical measurements in the West Antarctic Ice Sheet Divide, Byrd, and other ice cores to document a unique, ∼192-y series of halogen-rich volcanic eruptions exactly at the start of accelerated deglaciation, with tephra identifying the nearby Mount Takahe volcano as the source. Extensive fallout from these massive eruptions has been found >2,800 km from Mount Takahe. Sulfur isotope anomalies and marked decreases in ice core bromine consistent with increased surface UV radiation indicate that the eruptions led to stratospheric ozone depletion. Rather than a highly improbable coincidence, circulation and climate changes extending from the Antarctic Peninsula to the subtropics-similar to those associated with modern stratospheric ozone depletion over Antarctica-plausibly link the Mount Takahe eruptions to the onset of accelerated Southern Hemisphere deglaciation ∼17.7 ka.

  15. Synchronous volcanic eruptions and abrupt climate change ˜17.7 ka plausibly linked by stratospheric ozone depletion

    NASA Astrophysics Data System (ADS)

    McConnell, Joseph R.; Burke, Andrea; Dunbar, Nelia W.; Köhler, Peter; Thomas, Jennie L.; Arienzo, Monica M.; Chellman, Nathan J.; Maselli, Olivia J.; Sigl, Michael; Adkins, Jess F.; Baggenstos, Daniel; Burkhart, John F.; Brook, Edward J.; Buizert, Christo; Cole-Dai, Jihong; Fudge, T. J.; Knorr, Gregor; Graf, Hans-F.; Grieman, Mackenzie M.; Iverson, Nels; McGwire, Kenneth C.; Mulvaney, Robert; Paris, Guillaume; Rhodes, Rachael H.; Saltzman, Eric S.; Severinghaus, Jeffrey P.; Steffensen, Jørgen Peder; Taylor, Kendrick C.; Winckler, Gisela

    2017-09-01

    Glacial-state greenhouse gas concentrations and Southern Hemisphere climate conditions persisted until ˜17.7 ka, when a nearly synchronous acceleration in deglaciation was recorded in paleoclimate proxies in large parts of the Southern Hemisphere, with many changes ascribed to a sudden poleward shift in the Southern Hemisphere westerlies and subsequent climate impacts. We used high-resolution chemical measurements in the West Antarctic Ice Sheet Divide, Byrd, and other ice cores to document a unique, ˜192-y series of halogen-rich volcanic eruptions exactly at the start of accelerated deglaciation, with tephra identifying the nearby Mount Takahe volcano as the source. Extensive fallout from these massive eruptions has been found >2,800 km from Mount Takahe. Sulfur isotope anomalies and marked decreases in ice core bromine consistent with increased surface UV radiation indicate that the eruptions led to stratospheric ozone depletion. Rather than a highly improbable coincidence, circulation and climate changes extending from the Antarctic Peninsula to the subtropics—similar to those associated with modern stratospheric ozone depletion over Antarctica—plausibly link the Mount Takahe eruptions to the onset of accelerated Southern Hemisphere deglaciation ˜17.7 ka.

  16. Simulations of Arctic ozone depletion with current and doubled levels of CO2

    NASA Technical Reports Server (NTRS)

    Butchart, Neal; Austin, John; Shine, Keith P.

    1994-01-01

    Results from idealized 3-D simulations of a dynamical-radiative-photochemical model of the stratosphere are presented for the Northern Hemisphere winter and spring. For a simulation of a quiescent winter, it is found that with current levels of CO2 only modest polar ozone depletion occurs, consistent with observations. For a second simulation with the same planetary wave amplitudes in the upper troposphere but with doubled CO2, the model predicts a northern hemisphere ozone hole comparable to that observed in Antarctica with almost complete ozone destruction at 20 km. Reasons for the marked difference between the simulations are identified.

  17. Terrestrial Ozone Depletion Due to a Milky Way Gamma-Ray Burst

    NASA Technical Reports Server (NTRS)

    Thomas, Brian C.; Jackman, Charles H.; Melott, Adrian L.; Laird, Claude M.; Stolarski, Richard S.; Gehrels, Neil; Cannizzo, John K.; Hogan, Daniel P.

    2005-01-01

    Based on cosmological rates, it is probable that at least once in the last Gy the Earth has been irradiated by a gamma-ray burst in our Galaxy from within 2 kpc. Using a two-dimensional atmospheric model we have computed the effects upon the Earth's atmosphere of one such burst. A ten second burst delivering 100 kJ/sq m to the Earth results in globally averaged ozone depletion of 35%, with depletion reaching 55% at some latitudes. Significant global depletion persists for over 5 years after the burst. This depletion would have dramatic implications for life since a 50% decrease in ozone column density results in approximately three times the normal UVB flux. Widespread extinctions are likely, based on extrapolation from UVB sensitivity of modern organisms.

  18. Persistent Polar Depletion of Stratospheric Ozone and Emergent Mechanisms of Ultraviolet Radiation-Mediated Health Dysregulation

    PubMed Central

    Dugo, Mark A.; Han, Fengxiang

    2013-01-01

    Year 2011 noted the first definable ozone “hole” in the Arctic region, serving as an indicator to the continued threat of dangerous ultraviolet radiation (UVR) exposure caused by the deterioration of stratospheric ozone in the northern hemisphere. Despite mandates of the Montreal Protocol to phase out the production of ozone depleting chemicals (ODCs), the relative stability of ODCs validates popular notions of persistent stratospheric ozone for several decades. Moreover, increased UVR exposure through stratospheric ozone depletion is occurring within a larger context of physiological stress and climate change across the biosphere. In this review, we provide commentaries on stratospheric ozone depletion with relative comparisons between the well-known Antarctic ozone hole and the newly defined ozone hole in the Arctic. Compared to the Antarctic region, increased UVR exposure in the Northern Hemisphere poses a threat to denser human populations across North America, Europe and Asia. In this context, we discuss emerging targets of UVR exposure that can potentially offset normal biological rhythms in terms of taxonomically conserved photoperiod dependent seasonal signaling and entrainment of circadian clocks. Consequences of seasonal shifts during critical life history stages can alter the fitness and condition, while circadian disruption is increasingly becoming associated as a causal link to increased carcinogenesis. We further review the significance of genomic alterations via UVR induced modulations of phase I and phase II transcription factors, the aryl hydrocarbon receptor (AhR) and the Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), with emphasis on mechanism that can lead to metabolic shifts and cancer. While concern for adverse health consequences due to increased UVR exposure are longstanding, recent advances in biochemical research suggest that AhR and Nrf2 transcriptional regulators are likely targets for UVR mediated dysregulations of rhymicity

  19. Persistent polar depletion of stratospheric ozone and emergent mechanisms of ultraviolet radiation-mediated health dysregulation.

    PubMed

    Dugo, Mark A; Han, Fengxiang; Tchounwou, Paul B

    2012-01-01

    Year 2011 noted the first definable ozone "hole" in the Arctic region, serving as an indicator to the continued threat of dangerous ultraviolet radiation (UVR) exposure caused by the deterioration of stratospheric ozone in the northern hemisphere. Despite mandates of the Montreal Protocol to phase out the production of ozone-depleting chemicals (ODCs), the relative stability of ODCs validates popular notions of persistent stratospheric ozone for several decades. Moreover, increased UVR exposure through stratospheric ozone depletion is occurring within a larger context of physiologic stress and climate change across the biosphere. In this review, we provide commentaries on stratospheric ozone depletion with relative comparisons between the well-known Antarctic ozone hole and the newly defined ozone hole in the Arctic. Compared with the Antarctic region, the increased UVR exposure in the Northern Hemisphere poses a threat to denser human populations across North America, Europe, and Asia. In this context, we discuss emerging targets of UVR exposure that can potentially offset normal biologic rhythms in terms of taxonomically conserved photoperiod-dependent seasonal signaling and entrainment of circadian clocks. Consequences of seasonal shifts during critical life history stages can alter fitness and condition, whereas circadian disruption is increasingly becoming associated as a causal link to increased carcinogenesis. We further review the significance of genomic alterations via UVR-induced modulations of phase I and II transcription factors located in skin cells, the aryl hydrocarbon receptor (AhR), and the nuclear factor (erythroid-derived 2)-related factor 2 (Nrf2), with emphasis on mechanism that can lead to metabolic shifts and cancer. Although concern for adverse health consequences due to increased UVR exposure are longstanding, recent advances in biochemical research suggest that AhR and Nrf2 transcriptional regulators are likely targets for UVR

  20. 21 CFR 2.125 - Use of ozone-depleting substances in foods, drugs, devices, or cosmetics.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., devices, or cosmetics. 2.125 Section 2.125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Specific Products Subject to the Federal Food, Drug, and Cosmetic Act § 2.125 Use of ozone-depleting substances in foods, drugs, devices, or cosmetics. (a) As used in this section, ozone-depleting...

  1. 21 CFR 2.125 - Use of ozone-depleting substances in foods, drugs, devices, or cosmetics.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., devices, or cosmetics. 2.125 Section 2.125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Specific Products Subject to the Federal Food, Drug, and Cosmetic Act § 2.125 Use of ozone-depleting substances in foods, drugs, devices, or cosmetics. (a) As used in this section, ozone-depleting...

  2. 21 CFR 2.125 - Use of ozone-depleting substances in foods, drugs, devices, or cosmetics.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., devices, or cosmetics. 2.125 Section 2.125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Specific Products Subject to the Federal Food, Drug, and Cosmetic Act § 2.125 Use of ozone-depleting substances in foods, drugs, devices, or cosmetics. (a) As used in this section, ozone-depleting...

  3. 21 CFR 2.125 - Use of ozone-depleting substances in foods, drugs, devices, or cosmetics.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., devices, or cosmetics. 2.125 Section 2.125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Specific Products Subject to the Federal Food, Drug, and Cosmetic Act § 2.125 Use of ozone-depleting substances in foods, drugs, devices, or cosmetics. (a) As used in this section, ozone-depleting...

  4. About Contribution of Ox-, HOx-, NOx-, ClOx- and BrOx-cycle in the Stratospheric Ozone Depletion in the XXIst Century

    NASA Astrophysics Data System (ADS)

    Larin, Igor

    2017-04-01

    Based on the previously proposed algorithm of calculation of limiting stages of the reaction prolongations in stratospheric ozone depletion cycles* a contribution of Ox-, HOx-, NOx-, ClOx- and BrOx-cycle in ozone destruction at the end of the XXIst century at the latitude of 50° N for different seasons have been calculated. Calculations have been performed using a two-dimensional interactive model SOCRATES, and data on the concentrations of the main greenhouse gases listed in the scenarios of the Intergovernmental Panel on Climate Change (IPCC) RCP 4.5, according to which the stabilization of radiative forcing to occur by the end of the XXIst century. The work presents data on the absolute rates of ozone destruction in the cycles and their relative contribution to the destruction of ozone in 1995 and 2100 respectively in the altitude range 15-55 km for March, June, September, and December at 50° N. * Igor Larin. On the Chain Length and Rate of Ozone Depletion in the Main Stratospheric Cycles//Atmospheric and Climate Sciences (2013) №8. P. 141-149. http://dx.doi.org/10.4236/acs.2013.31016

  5. Australian Students' Appreciation of the Greenhouse Effect and the Ozone Hole.

    ERIC Educational Resources Information Center

    Fisher, Brian

    1998-01-01

    Examines students' explanations of the greenhouse effect and the hole in the ozone layer, using a life-world and scientific dichotomy. Illuminates ideas often expressed in classrooms and sheds light on the progression in students' developing powers of explanation. Contains 17 references. (DDR)

  6. Australian Students' Appreciation of the Greenhouse Effect and the Ozone Hole.

    ERIC Educational Resources Information Center

    Fisher, Brian

    1998-01-01

    Examines students' explanations of the greenhouse effect and the hole in the ozone layer, using a life-world and scientific dichotomy. Illuminates ideas often expressed in classrooms and sheds light on the progression in students' developing powers of explanation. Contains 17 references. (DDR)

  7. Ozone Depletion at Mid-Latitudes: Coupling of Volcanic Aerosols and Temperature Variability to Anthropogenic Chlorine

    NASA Technical Reports Server (NTRS)

    Solomon, S.; Portmann, R. W.; Garcia, R. R.; Randel, W.; Wu, F.; Nagatani, R.; Gleason, J.; Thomason, L.; Poole, L. R.; McCormick, M. P.

    1998-01-01

    Satellite observations of total ozone at 40-60 deg N are presented from a variety of instruments over the time period 1979-1997. These reveal record low values in 1992-3 (after Pinatubo) followed by partial but incomplete recovery. The largest post-Pinatubo reductions and longer-term trends occur in spring, providing a critical test for chemical theories of ozone depletion. The observations are shown to be consistent with current understanding of the chemistry of ozone depletion when changes in reactive chlorine and stratospheric aerosol abundances are considered along with estimates of wave-driven fluctuations in stratospheric temperatures derived from global temperature analyses. Temperature fluctuations are shown to make significant contributions to model calculated northern mid-latitude ozone depletion due to heterogeneous chlorine activation on liquid sulfate aerosols at temperatures near 200-210 K (depending upon water vapor pressure), particularly after major volcanic eruptions. Future mid-latitude ozone recovery will hence depend not only on chlorine recovery but also on temperature trends and/or variability, volcanic activity, and any trends in stratospheric sulfate aerosol.

  8. Ozone Depletion at Mid-Latitudes: Coupling of Volcanic Aerosols and Temperature Variability to Anthropogenic Chlorine

    NASA Technical Reports Server (NTRS)

    Solomon, S.; Portmann, R. W.; Garcia, R. R.; Randel, W.; Wu, F.; Nagatani, R.; Gleason, J.; Thomason, L.; Poole, L. R.; McCormick, M. P.

    1998-01-01

    Satellite observations of total ozone at 40-60 deg N are presented from a variety of instruments over the time period 1979-1997. These reveal record low values in 1992-3 (after Pinatubo) followed by partial but incomplete recovery. The largest post-Pinatubo reductions and longer-term trends occur in spring, providing a critical test for chemical theories of ozone depletion. The observations are shown to be consistent with current understanding of the chemistry of ozone depletion when changes in reactive chlorine and stratospheric aerosol abundances are considered along with estimates of wave-driven fluctuations in stratospheric temperatures derived from global temperature analyses. Temperature fluctuations are shown to make significant contributions to model calculated northern mid-latitude ozone depletion due to heterogeneous chlorine activation on liquid sulfate aerosols at temperatures near 200-210 K (depending upon water vapor pressure), particularly after major volcanic eruptions. Future mid-latitude ozone recovery will hence depend not only on chlorine recovery but also on temperature trends and/or variability, volcanic activity, and any trends in stratospheric sulfate aerosol.

  9. Arctic stratospheric ozone depletion and increased UVB radiation: potential impacts to human health.

    PubMed

    De Fabo, Edward C

    2005-12-01

    Contrary to popular belief, stratospheric ozone depletion, and the resultant increase in solar UV-B (280-320 nm), are unlikely to fully recover soon. Notwithstanding the success of the Montreal Protocol in reducing the amount of ozone destroying chemicals into the stratosphere, the life-times of these compounds are such that even with full compliance with the Protocol by all countries, it will be decades before stratospheric ozone could return to pre-1980 levels. This raises the question, therefore, of what will happen to biological processes essential to the maintenance of life on earth which are sensitive to damage by increased UV-B radiation, particularly those involved with human health? The polar regions, because of the vagaries of climate and weather, are the bellwether for stratospheric ozone depletion and will, therefore, be the first to experience impacts due to increases in solar UV-B radiation. The impacts of these are incompletely understood and cannot be predicted with certainty. While some UV-B impacts on human health are recognized, much is unknown, unclear and uncertain. Thus, this paper attempts, as a first approximation, to point out potential impacts to the health and welfare of human inhabitants of the Arctic due to increased solar UV-B radiation associated with stratospheric ozone depletion. As will be seen, much more data is critically needed before adequate risk assessment can occur.

  10. Circulation response to ozone depletion depends on the zonal wind climatology

    NASA Astrophysics Data System (ADS)

    Lin, P.; Paynter, D.; Polvani, L. M.; Correa, G. J. P.; Ming, Y.; Ramaswamy, V.

    2016-12-01

    Circulation response to ozone depletion is studied in two General Climate Models: CAM3 and GFDL AM3. Both models are forced with identical ozone change and long time-slice simulations are performed to minimize the influence of internal variability. While both models simulate a lower stratospheric cooling and a poleward shift of extratropical jet with ozone depletion, the magnitudes of these changes are significantly different in the two models. The stronger stratospheric cooling simulated by CAM3 is due to a delayed onset of a negative dynamical feedback to polar stratospheric temperature changes, which is linked to its delayed breakdown of the polar vortex. By applying artificial zonal wind forcing to AM3 in the stratosphere, we are able to alter the zonal wind climatology over southern extratropical stratosphere in AM3 without directly affecting its own internal variability. This modified version of AM3 yields similar zonal wind climatology as CAM3. It also simulates stronger stratospheric cooling to the same ozone forcing compared to the original AM3. Since the delayed breakdown of the polar vortex is a common bias in most climate models, results of this study implies that the circulation response to ozone depletion simulated in most models might be overestimated.

  11. Ozone depletion due to the use of chlorofluorocarbon: Government and industry response. (Latest citations from the Biobusiness database). Published Search

    SciTech Connect

    Not Available

    1994-12-01

    The bibliography contains citations concerning the response of business and government to atmospheric ozone depletion. Voluntary restrictions in the use of chlorofluorocarbons by industry and attempts to develop a substitute are examined. References cite studies of the ozone layer and the effects of aerosols worldwide, and examples of climatic models of ozone depletion. Government sponsored bans on chloroflourocarbons are examined. (Contains 250 citations and includes a subject term index and title list.)

  12. Ozone depletion due to the use of chlorofluorocarbon: Government and industry response. (Latest citations from the Biobusiness database). Published Search

    SciTech Connect

    Not Available

    1993-10-01

    The bibliography contains citations concerning the response of business and government to atmospheric ozone depletion. Voluntary restrictions in the use of chlorofluorocarbons by industry and attempts to develop a substitute are examined. References cite studies of the ozone layer and the effects of aerosols worldwide, and examples of climatic models of ozone depletion. Government sponsored bans on chloroflourocarbons are examined. (Contains 250 citations and includes a subject term index and title list.)

  13. Ozone depletion due to the use of chlorofluorocarbon: Government and industry response. (Latest citations from the Biobusiness database). Published Search

    SciTech Connect

    Not Available

    1993-12-01

    The bibliography contains citations concerning the response of business and government to atmospheric ozone depletion. Voluntary restrictions in the use of chlorofluorocarbons by industry and attempts to develop a substitute are examined. References cite studies of the ozone layer and the effects of aerosols worldwide, and examples of climatic models of ozone depletion. Government sponsored bans on chloroflourocarbons are examined. (Contains 250 citations and includes a subject term index and title list.)

  14. In Brief: SCISAT Studies Depletion of Ozone Layer; Healthy Corals Found in Caribbean

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    The Canadian Space Agency's SCISAT satellite began its mission to study the depletion of the ozone layer, following a successful launch on 12 August. The satellite began collecting data 50 minutes after its launch.A recent underwater survey has found that several Caribbean coral reefs are in better health than had been suspected, investigators announced on 24 July.

  15. Global Warming and Ozone Layer Depletion: STS Issues for Social Studies Classrooms.

    ERIC Educational Resources Information Center

    Rye, James A.; Strong, Donna D.; Rubba, Peter A.

    2001-01-01

    Explores the inclusion of science-technology-society (STS) education in social studies. Provides background information on global warming and the depletion of the ozone layer. Focuses on reasons for teaching global climate change in the social studies classroom and includes teaching suggestions. Offers a list of Web sites about global climate…

  16. Global Warming and Ozone Layer Depletion: STS Issues for Social Studies Classrooms.

    ERIC Educational Resources Information Center

    Rye, James A.; Strong, Donna D.; Rubba, Peter A.

    2001-01-01

    Explores the inclusion of science-technology-society (STS) education in social studies. Provides background information on global warming and the depletion of the ozone layer. Focuses on reasons for teaching global climate change in the social studies classroom and includes teaching suggestions. Offers a list of Web sites about global climate…

  17. Substitutes for ozone depleting aerosol electrical contact cleaners and cleaner/lubricants. Technical report

    SciTech Connect

    Bevilacqua, P.; Clark, K.G.

    1996-01-24

    With the production of Class I Ozone Depleting Substances discontinued as of January 1996, it became necessary to identify suitable replacements for chlorofluorocarbon (CFC-113) and trichloroethane (TCA) based electrical contact cleaners and cleaner/lubricant products. Two hydrochlorofluorocarbon (HCFC-141b) blends were identified as substitutes and recommended for interim use.

  18. Green Consciousness or Dollar Diplomacy? The British Response to the Threat of Ozone Depletion.

    ERIC Educational Resources Information Center

    Maxwell, James H.; Weiner, Sanford L.

    1993-01-01

    Discusses the British role in the regulation of believed ozone-depleting substances such as chlorofluorocarbons. Recounts the history of the British policies during the emergence of the issue from 1974-80; a period of tactical resistance from 1980-87; and a change in policy from 1987-90. (66 references) (MDH)

  19. INTERACTIVE EFFECTS OF OZONE DEPLETION AND CLIMATE CHANGE ON BIOGEOCHEMICAL CYCLES

    EPA Science Inventory

    The effects of ozone depletion on global biogeochemical cycles, via increased UV-B radiation at the Earth's surface, have continued to be documented over the past 4 years. In this report we also document various effects of UV-B that interact with global climate change because the...

  20. Environmental effects of ozone depletion and its interactions with climate change: progress report, 2015

    EPA Science Inventory

    The Environmental Effects Assessment Panel (EEAP) is one of three Panels that regularly informs the Parties (countries) to the Montreal Protocol on the effects of ozone depletion and the consequences of climate change interactions with respect to human health, animals, plants, bi...

  1. LOW OZONE-DEPLETING HALOCARBONS AS TOTAL-FLOOD AGENTS: VOLUME 1. CANDIDATE SURVEY

    EPA Science Inventory

    The volume describes an effort to identify chemical fire protection and explosion prevention agents which may replace the ozone-depleting agent Halon-1301 (CF3Br). Halon-1301 is used in total-flood fire protection systems where the agent is released as a gas into an enclosed spac...

  2. Environmental effects of ozone depletion and its interactions with climate change: progress report, 2015

    EPA Science Inventory

    The Environmental Effects Assessment Panel (EEAP) is one of three Panels that regularly informs the Parties (countries) to the Montreal Protocol on the effects of ozone depletion and the consequences of climate change interactions with respect to human health, animals, plants, bi...

  3. Simulation of ozone depletion using ambient irradiance supplemented with UV lamps.

    PubMed

    Díaz, S; Camilión, C; Escobar, J; Deferrari, G; Roy, S; Lacoste, K; Demers, S; Belzile, C; Ferreyra, G; Gianesella, S; Gosselin, M; Nozais, C; Pelletier, E; Schloss, I; Vernet, M

    2006-01-01

    In studies of the biological effects of UV radiation, ozone depletion can be mimicked by performing the study under ambient conditions and adding radiation with UV-B lamps. We evaluated this methodology at three different locations along a latitudinal gradient: Rimouski (Canada), Ubatuba (Brazil) and Ushuaia (Argentina). Experiments of the effect of potential ozone depletion on marine ecosystems were carried out in large outdoor enclosures (mesocosms). In all locations we simulated irradiances corresponding to 60% ozone depletion, which may produce a 130-1900% increase in 305 nm irradiance at noon, depending on site and season. Supplementation with a fixed percentage of ambient irradiance provides a better simulation of irradiance increase due to ozone depletion than supplementation with a fixed irradiance value, particularly near sunrise and sunset or under cloudy skies. Calculations performed for Ushuaia showed that, on very cloudy days, supplementation by the square-wave method may produce unrealistic irradiances. Differences between the spectra of the calculated supplementing irradiance and the lamp for a given site and date will be a function of the time of day and may become more or less pronounced according to the biological weighting function of the effect under study.

  4. LOW OZONE-DEPLETING HALOCARBONS AS TOTAL-FLOOD AGENTS: VOLUME 1. CANDIDATE SURVEY

    EPA Science Inventory

    The volume describes an effort to identify chemical fire protection and explosion prevention agents which may replace the ozone-depleting agent Halon-1301 (CF3Br). Halon-1301 is used in total-flood fire protection systems where the agent is released as a gas into an enclosed spac...

  5. INTERACTIVE EFFECTS OF OZONE DEPLETION AND CLIMATE CHANGE ON BIOGEOCHEMICAL CYCLES

    EPA Science Inventory

    The effects of ozone depletion on global biogeochemical cycles, via increased UV-B radiation at the Earth's surface, have continued to be documented over the past 4 years. In this report we also document various effects of UV-B that interact with global climate change because the...

  6. Selecting corporate political tactics: The Montreal Protocol on substances that deplete the ozone layer

    SciTech Connect

    Getz, K.A.

    1991-01-01

    This study examines factors influencing the choice of one set of tactics over others. The case of ozone depletion is used as the research context, and the data are drawn from US companies having a stake in this issue. A model is developed which suggests that a firm's choice of political tactics (dependent variable) is dependent on the targets of political activity and the nature of the issue of concern (independent variables), and a variety of organizational and industry factors (moderating variables). The paradigm of agency is used to systematically assess the relative importance of these factors. To test the relevance of the model, an empirical study was done. The case of the Montreal protocol on Substances That Deplete the Ozone Layer was chosen as a setting; and 551 firms directly affected by policy intended to protect the ozone layer were surveyed. There were 151 usable responses. Generally, the findings were consistent with the model.

  7. Are chlorine-free compounds a solution for health problems caused by ozone-depleting substances?

    PubMed

    Valić, F; Beritić-Stahuljak, D

    1996-01-01

    In January 1996, the Government of Croatia and United Nations Environment Programme (UNEP) signed an agreement on the phasing out of ozone-depleting substances in Croatia, making the problem of identifying adequate substitutes a high priority. In this paper, the main ecologic characteristics of chlorine-containing fully halogenated chlorofluorocarbons (CFCs) and partially halogenated chlorofluorocarbons (HCFCs) compared with chlorine-free hydrofluorocarbons (HFCs) are presented. The data showed HCFCs to be ecologically more acceptable than CFCs, particularly regarding the ozone-depleting potential (ODP), and have therefore been proposed as substitutes for CFCs. However, although having lower ODP, long-term they could still harm the stratospheric ozone layer, and are therefore hardly acceptable. HFCs are promising substitutes which, having no chlorine, have no ODP. Six were toxicologically evaluated; three of them were found flammable. Toxicological characteristics of three nonflammable compounds (HFC 125, HFC 134a and HFC 227ea) are presented. Their toxicity, not yet completely evaluated, appears to be low.

  8. Performance of resistive plate counter with non-ozone depletion freon

    SciTech Connect

    Sanpei, M.; Hoshi, Y.; Abe, K.

    1996-12-31

    The standard gas mixture (Ar/isoC{sub 4}H{sub 10}/CF{sub 3}Br) used for RPCs contains several percent of CF{sub 3}Br(Haron1301) as quenching agent. CF{sub 3}Br is known to destroy the atmospheric ozone layer. For this reason its use is discouraged, and prohibited by law in the near future. C{sub 2}F{sub 6}(FC116) and C{sub 2}H{sub 2}F{sub 4}(HFC134A) seem to be an ideal candidate from an environment point of view since its ozone depletion potential is very low. We present the results of a test performance on RPC (glass) operating with non-ozone depletion freon gas and butane-silver.

  9. NOx Catalyzed Pathway of Stratospheric Ozone Depletion: A Coupled Cluster Investigation.

    PubMed

    Dutta, Achintya Kumar; Vaval, Nayana; Pal, Sourav

    2012-06-12

    We report a theoretical investigation on the NOx catalyzed pathways of stratospheric ozone depletion using highly accurate coupled cluster methods. These catalytic reactions represent a great challenge to state-of-the-art ab initio methods, while their mechanisms remain unclear to both experimentalists and theoreticians. In this work, we have used the so-called "gold standard of quantum chemistry," the CCSD(T) method, to identify the saddle points on NOx-based reaction pathways of ozone hole formation. Energies of the saddle points are calculated using the multireference variants of coupled cluster methods. The calculated activation energies and rate constants show good agreement with available experimental results. Tropospheric precursors to stratospheric NOx radicals have been identified, and their potential importance in stratospheric chemistry has been discussed. Our calculations resolve previous conflicts between ab initio and experimental results for a trans nitro peroxide intermediate, in the NOx catalyzed pathway of ozone depletion.

  10. Ozone depletion and solar ultraviolet radiation: ocular effects, a United nations environment programme perspective.

    PubMed

    Cullen, Anthony P

    2011-07-01

    To describe he role played by the United Nations Environmental Effects Panel with respect to the ocular effects of stratospheric ozone depletion and present the essence of the Health Chapter of the 2010 Assessment. A consideration of solar ultraviolet radiation (UVR) at the Earth's surface as it is affected by atmospheric changes and how these influence sunlight-related eye diseases. A review of the current Assessment with emphasis on pterygium, cataract, ocular melanoma, and age-related macular degeneration. Although the ozone layer is projected to recover slowly in the coming decades, continuing vigilance is required regarding exposure to the sun. Evidence implicating solar UVR, especially UVB, in every tissue of the eye continues to be amassed. The need for ocular UV protection existed before the discovery of the depletion of the ozone layer and will continue even when the layer fully recovers in approximately 2100.

  11. Improvements in Total Column Ozone in GEOSCCM and Comparisons with a New Ozone-Depleting Substances Scenario

    NASA Technical Reports Server (NTRS)

    Oman, Luke D.; Douglass, Anne R.

    2014-01-01

    The evolution of ozone is examined in the latest version of the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM) using old and new ozone-depleting substances (ODS) scenarios. This version of GEOSCCM includes a representation of the quasi-biennial oscillation, a more realistic implementation of ozone chemistry at high solar zenith angles, an improved air/sea roughness parameterization, and an extra 5 parts per trillion of CH3Br to account for brominated very short-lived substances. Together these additions improve the representation of ozone compared to observations. This improved version of GEOSCCM was used to simulate the ozone evolution for the A1 2010 and the newStratosphere-troposphere Processes and their Role in Climate (SPARC) 2013 ODS scenario derived using the SPARC Lifetimes Report 2013. This new ODS scenario results in a maximum Cltot increase of 65 parts per trillion by volume (pptv), decreasing slightly to 60 pptv by 2100. Approximately 72% of the increase is due to the longer lifetime of CFC-11. The quasi-global (60degS-60degN) total column ozone difference is relatively small and less than 1Dobson unit on average and consistent with the 3-4% larger 2050-2080 average Cly in the new SPARC 2013 scenario. Over high latitudes, this small change in Cly compared to the relatively large natural variabilitymakes it not possible to discern a significant impact on ozone in the second half of the 21st century in a single set of simulations.

  12. On the "ozone deficit problem": what are Ox and HOx catalytic cycles for ozone depletion hiding?

    PubMed

    Varandas, António J C

    2002-05-17

    Studies on the role of vibrational excitation in the reactants for the O2 + O2, OH + O2, and HO2 + O2 reactions show that they can be important sources of ozone in the stratosphere, particularly at conditions of local thermodynamic disequilibrium. The results suggest that the Ox and HOx cycles commonly viewed as catalytic sinks of ozone may actually lead to its production, and hence help to clarify the "ozone deficit problem". This paper also presents an explanation for the general overestimation of the OH abundance in the upper stratosphere and lower mesosphere through standard HOx chemistry.

  13. A quantitative analysis of the reactions involved in stratospheric ozone depletion in the polar vortex core

    NASA Astrophysics Data System (ADS)

    Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

    2017-09-01

    We present a quantitative analysis of the chemical reactions involved in polar ozone depletion in the stratosphere and of the relevant reaction pathways and cycles. While the reactions involved in polar ozone depletion are well known, quantitative estimates of the importance of individual reactions or reaction cycles are rare. In particular, there is no comprehensive and quantitative study of the reaction rates and cycles averaged over the polar vortex under conditions of heterogeneous chemistry so far. We show time series of reaction rates averaged over the core of the polar vortex in winter and spring for all relevant reactions and indicate which reaction pathways and cycles are responsible for the vortex-averaged net change of the key species involved in ozone depletion, i.e., ozone, chlorine species (ClOx, HCl, ClONO2), bromine species, nitrogen species (HNO3, NOx) and hydrogen species (HOx). For clarity, we focus on one Arctic winter (2004-2005) and one Antarctic winter (2006) in a layer in the lower stratosphere around 54 hPa and show results for additional pressure levels and winters in the Supplement. Mixing ratios and reaction rates are obtained from runs of the ATLAS Lagrangian chemistry and transport model (CTM) driven by the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis data. An emphasis is put on the partitioning of the relevant chemical families (nitrogen, hydrogen, chlorine, bromine and odd oxygen) and activation and deactivation of chlorine.

  14. Environmental effects of ozone depletion and its interactions with climate change: progress report, 2008.

    PubMed

    Andrady, Anthony; Aucamp, Pieter J; Bais, Alkiviadis; Ballaré, Carlos L; Björn, Lars Olof; Bornman, Janet F; Caldwell, Martyn; Cullen, Anthony P; Erickson, David J; de Gruijl, Frank R; Häder, Donat-P; Ilyas, Mohammad; Kulandaivelu, G; Kumar, H D; Longstreth, Janice; McKenzie, Richard L; Norval, Mary; Paul, Nigel; Redhwi, Halim Hamid; Smith, Raymond C; Solomon, Keith R; Sulzberger, Barbara; Takizawa, Yukio; Tang, Xiaoyan; Teramura, Alan H; Torikai, Ayako; van der Leun, Jan C; Wilson, Stephen R; Worrest, Robert C; Zepp, Richard G

    2009-01-01

    After the enthusiastic celebration of the 20th Anniversary of the Montreal Protocol on Substances that Deplete the Ozone Layer in 2007, the work for the protection of the ozone layer continues. The Environmental Effects Assessment Panel is one of the three expert panels within the Montreal Protocol. This EEAP deals with the increase of the UV irradiance on the Earth's surface and its effects on human health, animals, plants, biogeochemistry, air quality and materials. For the past few years, interactions of ozone depletion with climate change have also been considered. It has become clear that the environmental problems will be long-lasting. In spite of the fact that the worldwide production of ozone depleting chemicals has already been reduced by 95%, the environmental disturbances are expected to persist for about the next half a century, even if the protective work is actively continued, and completed. The latest full report was published in Photochem. Photobiol. Sci., 2007, 6, 201-332, and the last progress report in Photochem. Photobiol. Sci., 2008, 7, 15-27. The next full report on environmental effects is scheduled for the year 2010. The present progress report 2008 is one of the short interim reports, appearing annually.

  15. TOPICAL REVIEW: Climate change, ozone depletion and the impact on ultraviolet exposure of human skin

    NASA Astrophysics Data System (ADS)

    Diffey, Brian

    2004-01-01

    For 30 years there has been concern that anthropogenic damage to the Earth's stratospheric ozone layer will lead to an increase of solar ultraviolet (UV) radiation reaching the Earth's surface, with a consequent adverse impact on human health, especially to the skin. More recently, there has been an increased awareness of the interactions between ozone depletion and climate change (global warming), which could also impact on human exposure to terrestrial UV. The most serious effect of changing UV exposure of human skin is the potential rise in incidence of skin cancers. Risk estimates of this disease associated with ozone depletion suggest that an additional peak incidence of 5000 cases of skin cancer per year in the UK would occur around the mid-part of this century. Climate change, which is predicted to lead to an increased frequency of extreme temperature events and high summer temperatures, will become more frequent in the UK. This could impact on human UV exposure by encouraging people to spend more time in the sun. Whilst future social trends remain uncertain, it is likely that over this century behaviour associated with climate change, rather than ozone depletion, will be the largest determinant of sun exposure, and consequent impact on skin cancer, of the UK population.

  16. A Two-Timescale Response to Ozone Depletion: Importance of the Background State

    NASA Astrophysics Data System (ADS)

    Seviour, W.; Waugh, D.; Gnanadesikan, A.

    2015-12-01

    It has been recently suggested that the response of Southern Ocean sea-ice extent to stratospheric ozone depletion is time-dependent; that the ocean surface initially cools due to enhanced northward Ekman drift caused by a poleward shift in the eddy-driven jet, and then warms after some time due to upwelling of warm waters from below the mixed layer. It is therefore possible that ozone depletion could act to favor a short-term increase in sea-ice extent. However, many uncertainties remain in understanding this mechanism, with different models showing widely differing time-scales and magnitudes of the response. Here, we analyze an ensemble of coupled model simulations with a step-function ozone perturbation. The two-timescale response is present with an approximately 30 year initial cooling period. The response is further shown to be highly dependent upon the background ocean temperature and salinity stratification, which is influenced by both natural internal variability and the isopycnal eddy mixing parameterization. It is suggested that the majority of inter-model differences in the Southern Ocean response to ozone depletion is caused by differences in stratification.

  17. Climate change, ozone depletion and the impact on ultraviolet exposure of human skin.

    PubMed

    Diffey, Brian

    2004-01-07

    For 30 years there has been concern that anthropogenic damage to the Earth's stratospheric ozone layer will lead to an increase of solar ultraviolet (UV) radiation reaching the Earth's surface, with a consequent adverse impact on human health, especially to the skin. More recently, there has been an increased awareness of the interactions between ozone depletion and climate change (global warming), which could also impact on human exposure to terrestrial UV. The most serious effect of changing UV exposure of human skin is the potential rise in incidence of skin cancers. Risk estimates of this disease associated with ozone depletion suggest that an additional peak incidence of 5000 cases of skin cancer per year in the UK would occur around the mid-part of this century. Climate change, which is predicted to lead to an increased frequency of extreme temperature events and high summer temperatures, will become more frequent in the UK. This could impact on human UV exposure by encouraging people to spend more time in the sun. Whilst future social trends remain uncertain, it is likely that over this century behaviour associated with climate change, rather than ozone depletion, will be the largest determinant of sun exposure, and consequent impact on skin cancer, of the UK population.

  18. Estimates of ozone depletion and skin cancer incidence to examine the Vienna Convention achievements

    NASA Astrophysics Data System (ADS)

    Slaper, Harry; Velders, Guus J. M.; Daniel, John S.; de Gruijl, Frank R.; van der Leun, Jan C.

    1996-11-01

    DEPLETION of the ozone layer has been observed on a global scale1, and is probably related to halocarbon emissions. Ozone depletion increases the biologically harmful solar ultraviolet radiation reaching the surface of the Earth, which leads to a variety of adverse effects, including an increase in the incidence of skin cancer. The 1985 Vienna Convention provided the framework for international restrictions on the production of ozone-depleting substances. The consequences of such restrictions have not yet been assessed in terms of effects avoided. Here we present a new method of estimating future excess skin cancer risks which is used to compare effects of a 'no restrictions' scenario with two restrictive scenarios specified under the Vienna Convention: the Montreal Protocol, and the much stricter Copenhagen Amendments. The no-restrictions and Montreal Protocol scenarios produce a runaway increase in skin cancer incidence, up to a quadrupling and doubling, respectively, by the year 2100. The Copenhagen Amendments scenario leads to an ozone minimum around the year 2000, and a peak relative increase in incidence of skin cancer of almost 10% occurring 60 years later. These results demonstrate the importance of the international measures agreed upon under the Vienna Convention.

  19. Monitoring of singlet oxygen in the lower troposphere and processes of ozone depletion.

    NASA Astrophysics Data System (ADS)

    Iasenko, Egor; Chelibanov, Vladimir; Marugin, Alexander; Kozliner, Marat

    2016-04-01

    The processes of ozone depletion in the atmosphere are widely discussed now in a connection with the problem of a global climate changes. It is known fact that photolysis of ozone in the upper atmosphere is the source of metastable molecules of oxygen. But, metastable molecules of oxygen can be formed as a result of photo initiated heterogeneous oxidation of molecules adsorbed on the surface of natural aerosol particles. During the outdoor experiment, we observed a formation of Singlet oxygen (1Δg) at concentration level of 2 ... 5 ppb when ice crystals have been exposed to the sun light. In experiments, we used Analyzers of Singlet oxygen and Ozone (produced by JSC "OPTEC") that utilize solid-state chemiluminescence technology. We assumed that the singlet oxygen is formed in the active centers on the surface of ice crystals in the presence or absence of anthropogenic pollutants in the atmosphere. Identified efficiency of heterogeneous reaction of O2 (1Δg) formation suggests the importance of the additional channel O3 + O2 (1Δg) → 2O2 + O (3P) of atmospheric ozone removal comparable with other well known cycles of ozone depletion.

  20. In situ measurements constraining the role of sulphate aerosols in mid-latitude ozone depletion

    NASA Technical Reports Server (NTRS)

    Fahey, D. W.; Kawa, S. R.; Woodbridge, E. L.; Tin, P.; Wilson, J. C.; Jonsson, H. H.; Dye, J. E.; Baumgardner, D.; Borrmann, S.; Toohey, D. W.

    1993-01-01

    In situ measurements of stratospheric sulphate aerosol, reactive nitrogen and chlorine concentrations at middle latitudes confirm the importance of aerosol surface reactions that convert active nitrogen to a less active, reservoir form. This makes mid-latitude stratospheric ozone less vulnerable to active nitrogen and more vulnerable to chlorine species. The effect of aerosol reactions on active nitrogen depends on gas phase reaction rates, so that increases in aerosol concentration following volcanic eruptions will have only a limited effect on ozone depletion at these latitudes.

  1. Quantification of relative contribution of Antarctic ozone depletion to increased austral extratropical precipitation during 1979-2013

    NASA Astrophysics Data System (ADS)

    Bai, Kaixu; Chang, Ni-Bin; Gao, Wei

    2016-02-01

    Attributing the observed climate changes to relevant forcing factors is critical to predicting future climate change scenarios. Precipitation observations in the Southern Hemisphere indicate an apparent moistening pattern over the extratropics during the time period 1979 to 2013. To investigate the predominant forcing factor in triggering such an observed wetting climate pattern, precipitation responses to four climatic forcing factors, including Antarctic ozone, water vapor, sea surface temperature (SST), and carbon dioxide, were assessed quantitatively in sequence through an inductive approach. Coupled time-space patterns between the observed austral extratropical precipitation and each climatic forcing factor were firstly diagnosed by using the maximum covariance analysis (MCA). With the derived time series from each coupled MCA modes, statistical relationships were established between extratropical precipitation variations and each climatic forcing factor by using the extreme learning machine. Based on these established statistical relationships, sensitivity tests were conducted to estimate precipitation responses to each climatic forcing factor quantitatively. Quantified differential contribution with respect to those climatic forcing factors may explain why the observed austral extratropical moistening pattern is primarily driven by the Antarctic ozone depletion, while mildly modulated by the cooling effect of equatorial Pacific SST and the increased greenhouse gases, respectively.

  2. Uncertainty Analysis of Ozone-Depleting Substances: Mixing Ratios, EESC, ODPs, and GWPs

    NASA Astrophysics Data System (ADS)

    Velders, G. J.; Daniel, J. S.

    2013-12-01

    Important for the recovery of the ozone layer from depletion by ozone-depleting substances (ODSs) is the rate at which ODSs are removed from the atmosphere, that is, their lifetimes. Recently the WCRP/SPARC project conducted an assessment of lifetimes of ODSs [SPARC, 2013] and presented a new set of recommended lifetimes as well as their uncertainties. We present here a comprehensive uncertainty analysis of ODS mixing ratios, levels of equivalent effective stratospheric chlorine (EESC), radiative forcing, ozone depletion potentials (ODPs), and global warming potentials (GWPs), using the new lifetimes and their uncertainties as well as uncertainties on all other relevant parameters. Using a box model the year EESC returns to pre-1980 levels, a metric commonly used to indicate a level of recovery for ODS induced ozone depletion, is 2048 for mid-latitudes based on the new lifetimes, which is 2 years later than that based on the lifetimes from WMO [2011]. The uncertainty in this return time is much larger than this change, however. The year EESC returns to pre-1980 levels ranges from is 2038 to 2064 (95% CI) for mid-latitudes and 2060 to 2104 for the Antarctic. The largest contribution to these ranges comes from the uncertainties in the lifetimes, since the current atmospheric burden of CFCs is much larger than the amounts present in existing equipment or still being produced. The earlier end of the recovery times is comparable to the return time in a hypothetical scenario with a cease in anthropogenic ODS emissions in 2014. The upper end of the range corresponds with an extra emission of about 7 MtCFC-11-eq in 2015, or about twice the cumulative anthropogenic emissions of all ODSs from 2014 to 2050. Semi-empirical ODPs calculated using the lifetimes from SPARC [2013] are up to 25% lower than the data reported in WMO [2011] for most species, mainly as a result of the increase in the estimated lifetime of CFC-11. The ODP of Halon-2402 increases by 20%, while the only

  3. Environmental effects of ozone depletion and its interactions ...

    EPA Pesticide Factsheets

    When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than previously believed. As a result of this, human health and environmental issues will be longer-lasting and more regionally variable. Like the other Panels, the EEAP produces a detailed report every four years; the most recent was published as a series of seven papers in 2015 (Photochem. Photobiol. Sci., 2015, 14, 1-184). In the years in between, the EEAP produces less detailed and shorter Progress Reports of the relevant scientific findings. The most recent of these was for 2015 (Photochem. Photobiol. Sci., 2016, 15, 141-147). The present Progress Report for 2016 assesses some of the highlights and new insights with regard to the interactive nature of the direct and indirect effects of UV radiation, atmospheric processes, and climate change. The report is also published in (Photochem. Photobiol. Sci., 2017, DOI: 10.1039/c7pp90001e). The more detailed Quadrennial Assessment will be made available in 2018. The Parties to the Montreal Protocol are informed by three Panels of experts. One of these is the Environmental Effects Assessment Panel (EEAP), which deals with two focal issues. The first focus is the effects on increased UV radiation on human health, animals, plants, biogeochemistry, air quality, and materials. The second focus is on interactions between UV radiation and global climate change and how these may

  4. Ozone depletion. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1996-08-01

    The bibliography contains citations concerning studies of atmospheric chemistry and modeling of ozone depletion in Antarctica, and the consequences of the depletion on ultraviolet radiation levels. The studies involve chemical reactions in the atmosphere, including temperature dynamics, possible changes in solar insolation, and effects of pollution from nitrogen, chloroflourocarbons, carbon dioxide, and methane. The studies involve references to observations of the ozonosphere and modeling of interactions worldwide, together with data on the sources of the natural and man-made pollutants.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  5. Ozone depletion studies. (Latest citations from the Aerospace database). Published Search

    SciTech Connect

    Not Available

    1994-06-01

    The bibliography contains citations concerning studies of atmospheric chemistry and modeling of ozone depletion in Antarctica, and the consequences of the depletion on ultraviolet radiation levels. The studies involve chemical reactions in the atmosphere, including temperature dynamics, possible changes in solar insolation, and effects of pollution from nitrogen, chlorofluorocarbons, carbon dioxide and methane. The studies involve references to observations of the ozonosphere and modeling of interactions worldwide, together with data on the sources of the natural and man-made pollutants. (Contains a minimum of 145 citations and includes a subject term index and title list.)

  6. Ozone depletion. (Latest citations from the NTIS Bibliographic database). Published Search

    SciTech Connect

    Not Available

    1994-04-01

    The bibliography contains citations concerning studies of atmospheric chemistry and modeling of ozone depletion in Antarctica, and the consequences of the depletion on ultraviolet radiation levels. The studies involve chemical reactions in the atmosphere, including temperature dynamics, possible changes in solar insolation, and effects of pollution from nitrogen, chloroflourocarbons, carbon dioxide, and methane. The studies involve references to observations of the ozonosphere and modeling of interactions worldwide, together with data on the sources of the natural and man-made pollutants. (Contains a minimum of 200 citations and includes a subject term index and title list.)

  7. Stratospheric ozone depletion over Antarctica - Role of aerosols based on SAGE II satellite observations

    NASA Technical Reports Server (NTRS)

    Lin, N.-H.; Saxena, V. K.

    1992-01-01

    The physical characteristics of the Antarctic stratospheric aerosol are investigated via a comprehensive analysis of the SAGE II data during the most severe ozone depletion episode of October 1987. The aerosol size distribution is found to be bimodal in several instances using the randomized minimization search technique, which suggests that the distribution of a single mode may be used to fit the data in the retrieved size range only at the expense of resolution for the larger particles. On average, in the region below 18 km, a wavelike perturbation with the upstream tilting for the parameters of mass loading, total number, and surface area concentration is found to be located just above the region of the most severe ozone depletion.

  8. The role of the Mt. Merapi eruption in the 2011 Arctic ozone depletion

    NASA Astrophysics Data System (ADS)

    Zuev, V. V.; Zueva, N. E.; Savelieva, E. S.

    2017-10-01

    One of the strongest ozone depletion events in the Arctic stratosphere was observed in March 2011 due to the strengthening of the polar vortex in February 2011. Earlier, in November 2010, the eruption of Mt. Merapi volcano (Java, Indonesia) with a maximum plume altitude of 18.3 km was recorded. The effect of aerosol heating in the tropical lower stratosphere after the Mt. Merapi eruption on the Arctic polar vortex strengthening in winter-spring 2011 is examined. Based on the ERA-Interim reanalysis temperature data, we show that significant aerosol heating in the lower tropical stratosphere was observed in February-March 2011 and could lead to an increase in the stratospheric equator-to-pole temperature gradient resulting in an enhanced Arctic polar vortex. We also analyze the correlation between large tropical volcanic eruptions occurring in autumn-winter periods and Arctic ozone depletion events observed in the following winter-spring periods.

  9. Stratospheric ozone depletion over Antarctica - Role of aerosols based on SAGE II satellite observations

    NASA Technical Reports Server (NTRS)

    Lin, N.-H.; Saxena, V. K.

    1992-01-01

    The physical characteristics of the Antarctic stratospheric aerosol are investigated via a comprehensive analysis of the SAGE II data during the most severe ozone depletion episode of October 1987. The aerosol size distribution is found to be bimodal in several instances using the randomized minimization search technique, which suggests that the distribution of a single mode may be used to fit the data in the retrieved size range only at the expense of resolution for the larger particles. On average, in the region below 18 km, a wavelike perturbation with the upstream tilting for the parameters of mass loading, total number, and surface area concentration is found to be located just above the region of the most severe ozone depletion.

  10. Model predictions of latitude-dependent ozone depletion due to aerospace vehicle operations

    NASA Technical Reports Server (NTRS)

    Borucki, W. J.; Whitten, R. C.; Watson, V. R.; Riegel, C. A.; Maples, A. L.; Capone, L. A.

    1976-01-01

    Results are presented from a two-dimensional model of the stratosphere that simulates the seasonal movement of ozone by both wind and eddy transport, and contains all the chemistry known to be important. The calculated reductions in ozone due to NO2 injection from a fleet of supersonic transports are compared with the zonally averaged results of a three-dimensional model for a similar episode of injection. The agreement is good in the northern hemisphere, but is not as good in the southern hemisphere. Both sets of calculations show a strong corridor effect in that the predicted ozone depletions are largest to the north of the flight corridor for aircraft operating in the northern hemisphere.

  11. Influence of climate variability on near-surface ozone depletion events in the Arctic spring

    NASA Astrophysics Data System (ADS)

    Koo, Ja-Ho; Wang, Yuhang; Jiang, Tianyu; Deng, Yi; Oltmans, Samuel J.; Solberg, Sverre

    2014-04-01

    Near-surface ozone depletion events (ODEs) generally occur in the Arctic spring, and the frequency shows large interannual variations. We use surface ozone measurements at Barrow, Alert, and Zeppelinfjellet to analyze if their variations are due to climate variability. In years with frequent ODEs at Barrow and Alert, the western Pacific (WP) teleconnection pattern is usually in its negative phase, during which the Pacific jet is strengthened but the storm track originated over the western Pacific is weakened. Both factors tend to reduce the transport of ozone-rich air mass from midlatitudes to the Arctic, creating a favorable environment for the ODEs. The correlation of ODE frequencies at Zeppelinfjellet with WP indices is higher in the 2000s, reflecting stronger influence of the WP pattern in recent decade to cover ODEs in broader Arctic regions. We find that the WP pattern can be used to diagnose ODE changes and subsequent environmental impacts in the Arctic spring.

  12. The very short-lived ozone depleting substance CHBr3 (bromoform): Revised UV absorption spectrum, atmospheric lifetime and ozone depletion potential

    NASA Astrophysics Data System (ADS)

    Papanastasiou, Dimitrios K.; McKeen, Stuart A.; Burkholder, James B.

    2014-05-01

    more pronounced as wavelength increases and temperature decreases. The source of this discrepancy is further discussed. A parameterization of the CHBr3 UV spectrum for use in atmospheric models is developed and illustrative photolysis rate calculations are presented to highlight the impact of the revised σ(Λ,T) values on its calculated local lifetimes. For instance, CHBr3 atmospheric photolysis rate in the tropical region obtained with the present spectral data was found to be 10-15% lower (longer lifetime) than that obtained using the currently recommended values. Moreover, seasonally dependent ozone depletion potentials (ODPs) for CHBr3 emitted in the Indian sub-continent were calculated using the semi-empirical relationship of Brioude et al. (Brioude et al., Geophys. Res. Lett., 37, L19804, doi: 10.1029/2010GL044856, 2010) to evaluate the impact of the present results on stratospheric ozone. In conclusion, the present study reports improved UV absorption cross section data for the short-lived ozone depleting substance CHBr3, which are a result of high quality measurements and a thorough investigation of possible sources of systematic error. The CHBr3 UV cross section data, from this study, combined with OH kinetic data enables more accurate model predictions of stratospheric bromine loading and its impact on stratospheric ozone.

  13. An assessment of alternatives and technologies for replacing ozone- depleting substances at DOE facilities

    SciTech Connect

    Purcell, C.W.; Miller, K.B.; Friedman, J.R.; Rapoport, R.D.; Conover, D.R.; Hendrickson, P.L.; Koss, T.C.

    1992-10-01

    Title VI of the Clean Air Act, as amended, mandates a production phase-out for ozone-depleting substances (ODSs). These requirements will have a significant impact on US Department of Energy (DOE) facilities. Currently, DOE uses ODSs in three major activities: fire suppression (halon), refrigeration and cooling (chlorofluorocarbons [CFCs]), and cleaning that requires solvents (CFCs, methyl chloroform, and carbon tetrachloride). This report provides basic information on methods and strategies to phase out use of ODSs at DOE facilities.

  14. An assessment of alternatives and technologies for replacing ozone- depleting substances at DOE facilities

    SciTech Connect

    Purcell, C.W.; Miller, K.B.; Friedman, J.R.; Rapoport, R.D.; Conover, D.R.; Hendrickson, P.L. ); Koss, T.C. . Office of Environmental Guidance)

    1992-10-01

    Title VI of the Clean Air Act, as amended, mandates a production phase-out for ozone-depleting substances (ODSs). These requirements will have a significant impact on US Department of Energy (DOE) facilities. Currently, DOE uses ODSs in three major activities: fire suppression (halon), refrigeration and cooling (chlorofluorocarbons [CFCs]), and cleaning that requires solvents (CFCs, methyl chloroform, and carbon tetrachloride). This report provides basic information on methods and strategies to phase out use of ODSs at DOE facilities.

  15. Substituting HCFC-22 for HFC-410A: an environmental impact trade-off between the ozone depletion and climate change regimes

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Fang, X.; Zhang, J.

    2015-12-01

    After the phase-out of hydrochlorofluorocarbons (HCFCs) as ozone-depleting substances pursuant to the requirements of the Montreal Protocol, hydrofluorocarbons (HFCs) are worldwide used as substitutes although the bulk of them are potent greenhouse gases (GHGs). Therefore, the alternation may bring side effect on global climate change. The trade-off of its environmental impacts between the ozone depletion and climate change regimes necessitates a quantification of the past and future consumption and emissions of both the original HCFCs and their alternative HFCs. Now a dilemma arise in China's RAC industry that HCFC-22, which has an ozone-depleting potential (ODP) of 0.055, has been replaced by HFC-410A, which is a blended potent GHG from respective 50% HFC-32 and HFC-125 with a global warming potential (GWP) of 1923.5. Here, we present our results of estimates of consumption and emissions of HCFC-22 and HFC-410A from 1994 to 2050. Historic emissions of HCFC-22 contributed to global total HCFCs by 4.0% (3.0%-5.6%) ODP-weighted. Projection under a baseline scenario shows future accumulative emissions of HFC-410A make up 5.9%-11.0% of global GWP-weighted HFCs emissions, and its annual contribution to national overall CO2 emissions can be 5.5% in 2050. This makes HCFC-22 and HFC-410A emissions of significant importance in ozone depletion and climate change regimes. Two mitigation scenarios were set to assess the mitigation performance under the North America Proposal and an accelerated schedule. In practice of international environmental agreement, "alternative to alternative" should be developed to avoid regrettable alternations.

  16. Polar ozone depletion and trends as represented by the Whole Atmospheric Community Climate Model (WACCM)

    NASA Astrophysics Data System (ADS)

    Kinnison, Douglas; Solomon, Susan; Ivy, Diane; Mills, Michael; Neely, Ryan, III; Schmidt, Anja; Garcia, Rolando; Smith, Anne

    2016-04-01

    The Whole Atmosphere Community Climate Model, Version 4 (WACCM4) is a comprehensive numerical model, spanning the range of altitude from the Earth's surface to the lower thermosphere [Garcia et al., JGR, 2007; Kinnison et al., JGR, 2007; Marsh et al., J. of Climate, 2013]. WACCM4 is based on the framework of the NCAR Community Atmosphere Model, version 4 (CAM4), and includes all of the physical parameterizations of CAM4 and a finite volume dynamical core for the tracer advection. This version has a detailed representation of tropospheric and middle atmosphere chemical and physical processes. Simulations completed for the SPARC Chemistry Climate Model Initiative (CCMI), REFC1, REFC2, SENSC2, and REFC1SD scenarios are examined (see Eyring et al., SPARC Newsletter, 2013). Recent improvements in model representation of orographic gravity wave processes strongly impact temperature and therefore polar ozone depletion as well as its subsequent recovery. Model representation of volcanic events will also be shown to be important for ozone loss. Evaluation of polar ozone depletion processes (e.g., dehydration, denitrification, chemical activation) with key observations will be performed and the impact on future ozone recovery will be identified.

  17. Volcanic aerosol and ozone depletion within the Antarctic polar vortex during the austral spring of 1991

    SciTech Connect

    Deshler, T.; Adriani, A.; Gobbi, G.P.; Hofmann, D.J.; Donfrancesco, G. di; Johnson, B.J. CNR, Ist. de Fisica dell'Atmosfera, Frascati NOAA, Climate Monitoring and Diagnostics Lab., Boulder, CO ENEA, Centro Ricerche Energia Casaccia, Rome )

    1992-09-01

    In the spring of 1991 the Antarctic lower stratosphere was characterized by a layer of volcanic aerosol from the Cerro Hudson eruption. This aerosol layer was observed from McMurdo Station, Antarctica, with both lidar and balloonborne particle counters beginning around 10 September. After 20 September the aerosol was observed daily between 9 and 13 km. In this layer homogeneous nucleation of new aerosol was observed with concentrations greater than 6000/cu cm. Comparisons of scattering ratio calculated from measured particle size distributions agree best with the lidar measurements when a real index of refraction near 1.5 is used. In the past 5 years of measurements, ozone below 13 km has been relatively unchanged during the annual Antartic ozone depletion; however, in 1991 ozone below 13 km decreased at a rate of 4 - 8 ppb/day over 30 days. This change began shortly after the appearance of the volcanic aerosol, providing direct measurements correlating volcanic aerosol and ozone depletion. 16 refs.

  18. Reducing the emission of ozone depleting chemicals through use of a self-cleaning soldering process

    SciTech Connect

    Lichtenberg, L.; Martin, G.; Van Buren, P.; Iman, R.; Paffett, M.T.

    1991-12-31

    Motorola has jointed with Sandia and Los Alamos National Laboratories to perform work under a Cooperative Research and Development Agreement (CRADA) to reduce the use of CFC`s and other ozone depleting printing wiring board (PWB) cleaning solvents. This study evaluated the use of a new soldering process that uses dilute adipic acid in lieu of rosin flux. The process consumes the adipic acid in lieu of rosin flux. The process consumes the adipic acid during the soldering process and precludes the need for subsequent cleaning with ozone depleting solvents. This paper presents results from a series of designed experiments that evaluated PWB cleanliness as a function of various levels of machine control parameters. The study included a comprehensive hardware reliability evaluation, which included environmental conditioning, cleanliness testing, surface chemical analysis, surface insulation resistance testing, along with electrical, mechanical and long term storage testing. The results of this study that the new process produces quality, reliable hardware over a wide range of processing parameters. Adoption of this process, which eliminates the need for supplemental cleaning, will have a positive impact on many environmental problems, including depletion of the ozone layer.

  19. Reducing the emission of ozone depleting chemicals through use of a self-cleaning soldering process

    SciTech Connect

    Lichtenberg, L.; Martin, G.; Van Buren, P. . Government Electronics Group); Iman, R. ); Paffett, M.T. )

    1991-01-01

    Motorola has jointed with Sandia and Los Alamos National Laboratories to perform work under a Cooperative Research and Development Agreement (CRADA) to reduce the use of CFC's and other ozone depleting printing wiring board (PWB) cleaning solvents. This study evaluated the use of a new soldering process that uses dilute adipic acid in lieu of rosin flux. The process consumes the adipic acid in lieu of rosin flux. The process consumes the adipic acid during the soldering process and precludes the need for subsequent cleaning with ozone depleting solvents. This paper presents results from a series of designed experiments that evaluated PWB cleanliness as a function of various levels of machine control parameters. The study included a comprehensive hardware reliability evaluation, which included environmental conditioning, cleanliness testing, surface chemical analysis, surface insulation resistance testing, along with electrical, mechanical and long term storage testing. The results of this study that the new process produces quality, reliable hardware over a wide range of processing parameters. Adoption of this process, which eliminates the need for supplemental cleaning, will have a positive impact on many environmental problems, including depletion of the ozone layer.

  20. Terrestrial Ozone Depletion due to a Milky Way Gamma-Ray Burst

    NASA Astrophysics Data System (ADS)

    Thomas, Brian C.; Jackman, Charles H.; Melott, Adrian L.; Laird, Claude M.; Stolarski, Richard S.; Gehrels, Neil; Cannizzo, John K.; Hogan, Daniel P.

    2005-04-01

    Based on cosmological rates, it is probable that at least once in the last gigayear the Earth has been irradiated by a gamma-ray burst (GRB) in our Galaxy from within 2 kpc. We have performed the first detailed computation of the effects on the Earth's atmosphere of one such impulsive event: A 10 s 100 kJ m-2 burst penetrates to the stratosphere causing globally averaged ozone depletion of 35%, with depletion reaching 55% at some latitudes. Significant depletion persists for over 5 years after the burst. A 50% decrease in ozone column density leads to approximately 3 times the normal UVB (280-315 nm; a wavelength band that ozone significantly absorbs and that living organisms are sensitive to) flux, and widespread extinctions are likely, based on extrapolation from sensitivity of modern organisms. Additional effects include a shot of nitrate fertilizer and NO2 opacity in the visible, providing a cooling perturbation to the climate over a similar timescale. These results lend support to the hypothesis that a GRB may have initiated the late Ordovician mass extinction (Melott et al.).

  1. On the age of stratospheric air and ozone depletion potentials in polar regions

    NASA Technical Reports Server (NTRS)

    Pollock, W. H.; Heidt, L. E.; Lueb, R. A.; Vedder, J. F.; Mills, M. J.; Solomon, S.

    1992-01-01

    Observations of the nearly inert, man-made chlorofluorocarbon CFC-115 obtained during January 1989 are used to infer the age of air in the lower stratosphere. These observations together with estimated release rates suggest an average age of high-latitude air at pressure altitudes near 17-21 km of about 3 to 5 yr. This information is used together with direct measurements of HCFC-22, HCFC-142b, CH3Br, H-1301, H-1211, and H-2402 to examine the fractional dissociation of these species within the Arctic polar lower stratosphere compared to that of CFC-11 and hence to estimate their local ozone depletion potentials in this region. It is shown that these HCFCs are much less efficiently dissociated within the stratosphere than CFC-11, lowering their ozone depletion potentials to only about 30-40 percent of their chlorine loading potentials. In contrast, the observations of CH3Br and the Halons considered confirm that they are rapidly dissociated within the stratosphere, with important implications for their ozone depletion potentials.

  2. Heterogeneous conversion of HCl and ClONO{sub 2} during the Arctic winter 1992/1993 initiating ozone depletion

    SciTech Connect

    Notholt, J.; Gathen, P. von der; Peil, S.

    1995-06-20

    The authors report the results of studies of HCl and ClONO{sub 2} reservoir species in the arctic stratosphere during winter months by means of ground based FTIR, ozone sonde, and lidar measurements. During the winter of 1992/93 they observed strong depletion of these compounds, prior to the appearance of sunlight, which produced conditions conductive to strong ozone depletion with the first appearance of sunlight.

  3. Observations of stratospheric temperature changes coincident with the recent Antarctic ozone depletions

    NASA Technical Reports Server (NTRS)

    Randel, William J.; Newman, Paul A.

    1988-01-01

    A high degree of correlation between the recent decline in Antarctic total ozone and cooling of the stratosphere during Austral spring has been noted in several recent studies (e.g., Sekiguchi, 1986; Angel, 1986). This study analyzes the observed temperature trends in detail, focusing on the spatial and temporal aspects of the observed cooling. Ozone losses and stratospheric cooling can be correlated for several reasons: (1) ozone losses (from an unspecified cause) will directly reduce temperatures due to decreased solar ultraviolet absorption (Shine, 1986), and/or (2) changes in both ozone and temperature structure due to modification of stratospheric circulation patterns (Mahlman and Fels, 1986). In order to scrutinize various ozone depletion scenarios, detailed information on the observed temperature changes is necessary; the goal is to provide such data. The data used are National Meteorological Center (NMC) Climate Analysis Center (CAC) derived temperatures, covering 1000 to 1 mb (0 to 48 km), for the period 1979 to 1987. Discussions on data origin and quality (assessed by extensive comparisons with radiosonde observations), along with other details of these observations, can be found in Newman and Randel (1988).

  4. Uncertainty analysis of projections of ozone-depleting substances: mixing ratios, EESC, ODPs, and GWPs

    NASA Astrophysics Data System (ADS)

    Velders, G. J. M.; Daniel, J. S.

    2013-10-01

    The rates at which ozone depleting substances (ODSs) are removed from the atmosphere, that is, their lifetimes, are key factors for determining the rate of ozone layer recovery in the coming decades. We present here a comprehensive uncertainty analysis of future mixing ratios of ODSs, levels of equivalent effective stratospheric chlorine (EESC), ozone depletion potentials, and global warming potentials, using, among other information, the 2013 WCRP/SPARC assessment of lifetimes of ODSs and their uncertainties. The year EESC returns to pre-1980 levels, a metric commonly used to indicate a level of recovery from ODS-induced ozone depletion, is 2048 for mid-latitudes based on the lifetimes from the SPARC assessment, which is about 2 yr later than based on the lifetimes from the WMO assessment of 2011. However, the uncertainty in this return to 1980 levels is much larger than the 2 yr change. The year EESC returns to pre-1980 levels ranges from 2039 to 2064 (95% confidence interval) for mid-latitudes and 2061 to 2105 for the Antarctic spring. The primary contribution to these ranges comes from the uncertainty in the lifetimes. The earlier years of the return estimates are comparable to a hypothetical scenario in which emissions of ODSs cease in 2014. The later end of the range corresponds to a scenario containing an additional emission of about 7 Mt CFC-11-eq in 2015, which is the same as about 2 times the cumulative anthropogenic emissions of all ODSs from 2014 to 2050, or about 12 times the cumulative HCFC emissions from 2014 to 2050.

  5. 40 CFR Appendix H to Subpart A of... - Clean Air Act Amendments of 1990 Phaseout Schedule for Production of Ozone-Depleting Substances

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Phaseout Schedule for Production of Ozone-Depleting Substances H Appendix H to Subpart A of Part 82... STRATOSPHERIC OZONE Production and Consumption Controls Pt. 82, Subpt. A, App. H Appendix H to Subpart A of Part 82—Clean Air Act Amendments of 1990 Phaseout Schedule for Production of Ozone-Depleting...

  6. 40 CFR Appendix H to Subpart A of... - Clean Air Act Amendments of 1990 Phaseout Schedule for Production of Ozone-Depleting Substances

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Phaseout Schedule for Production of Ozone-Depleting Substances H Appendix H to Subpart A of Part 82... STRATOSPHERIC OZONE Production and Consumption Controls Pt. 82, Subpt. A, App. H Appendix H to Subpart A of Part 82—Clean Air Act Amendments of 1990 Phaseout Schedule for Production of Ozone-Depleting...

  7. 40 CFR Appendix H to Subpart A of... - Clean Air Act Amendments of 1990 Phaseout Schedule for Production of Ozone-Depleting Substances

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Phaseout Schedule for Production of Ozone-Depleting Substances H Appendix H to Subpart A of Part 82... STRATOSPHERIC OZONE Production and Consumption Controls Pt. 82, Subpt. A, App. H Appendix H to Subpart A of Part 82—Clean Air Act Amendments of 1990 Phaseout Schedule for Production of Ozone-Depleting...

  8. 40 CFR Appendix H to Subpart A of... - Clean Air Act Amendments of 1990 Phaseout Schedule for Production of Ozone-Depleting Substances

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Phaseout Schedule for Production of Ozone-Depleting Substances H Appendix H to Subpart A of Part 82... STRATOSPHERIC OZONE Production and Consumption Controls Pt. 82, Subpt. A, App. H Appendix H to Subpart A of Part 82—Clean Air Act Amendments of 1990 Phaseout Schedule for Production of Ozone-Depleting...

  9. 40 CFR Appendix H to Subpart A of... - Clean Air Act Amendments of 1990 Phaseout Schedule for Production of Ozone-Depleting Substances

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Phaseout Schedule for Production of Ozone-Depleting Substances H Appendix H to Subpart A of Part 82... STRATOSPHERIC OZONE Production and Consumption Controls Pt. 82, Subpt. A, App. H Appendix H to Subpart A of Part 82—Clean Air Act Amendments of 1990 Phaseout Schedule for Production of Ozone-Depleting...

  10. 77 FR 74381 - Protection of Stratospheric Ozone: Listing of Substitutes for Ozone Depleting Substances-Fire...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-14

    ... Depleting Substances--Fire Suppression and Explosion Protection AGENCY: Environmental Protection Agency (EPA... published a direct final rule and a companion proposed rule issuing listings for three fire suppressants... three fire suppressants under EPA's Significant New Alternatives Policy program (77 FR 58035)....

  11. Ideas and perspectives: Southwestern tropical Atlantic coral growth response to atmospheric circulation changes induced by ozone depletion in Antarctica

    NASA Astrophysics Data System (ADS)

    Evangelista, Heitor; Wainer, Ilana; Sifeddine, Abdelfettah; Corrège, Thierry; Cordeiro, Renato C.; Lamounier, Saulo; Godiva, Daniely; Shen, Chuan-Chou; Le Cornec, Florence; Turcq, Bruno; Lazareth, Claire E.; Hu, Ching-Yi

    2016-04-01

    Recent Southern Hemisphere (SH) atmospheric circulation, predominantly driven by stratospheric ozone depletion over Antarctica, has caused changes in climate across the extratropics. Here, we present evidence that the Brazilian coast (southwestern Atlantic) may have been impacted from both wind and sea-surface temperature changes derived from this process. Skeleton analysis of massive coral species living in shallow waters off Brazil are very sensitive to air-sea interactions, and seem to record this impact. Growth rates of Brazilian corals show a trend reversal that fits the ozone depletion evolution, confirming that ozone impacts are far reaching and potentially affect coastal ecosystems in tropical environments.

  12. Photoreactivation in Paramecium tetraurelia under conditions of various degrees of ozone layer depletion.

    PubMed

    Takahashi, Akihisa; Kumatani, Toshihiro; Usui, Saori; Tsujimura, Ryoko; Seki, Takaharu; Morimoto, Kouichi; Ohnishi, Takeo

    2005-01-01

    Photoreactivation (PR) is an efficient survival mechanism that helps protect cells against the harmful effects of solar-ultraviolet (UV) radiation. The PR mechanism involves photolyase, just one enzyme, and can repair DNA damage, such as cyclobutane-pyrimidine dimers (CPD) induced by near-UV/blue light, a component of sunlight. Although the balance of near-UV/blue light and far-UV light reaching the Earth's surface could be altered by the atmospheric ozone layer's depletion, experiments simulating this environmental change and its possible effects on life have not yet been performed. To quantify the strength of UVB in sunlight reaching the Earth's surface, we measured the number of CPD generated in plasmid DNA after UVB irradiation or exposure to sunlight. To simulate the increase of solar-UV radiation resulting from the ozone layer depletion, Paramecium tetraurelia was exposed to UVB and/or sunlight in clear summer weather. PR recovery after exposure to sunlight was complete at a low dose rate of 0.2 J/m2 x s, but was less efficient when the dose rate was increased by a factor of 2.5 to 0.5 J/m2 x s. It is suggested that solar-UV radiation would not influence the cell growth of P. tetraurelia for the reason of high PR activity even when the ozone concentration was decreased 30% from the present levels.

  13. Effects of Arctic ozone depletion and snow on UV exposure in Finland

    SciTech Connect

    Jokela, K.; Leszczynski, K.; Visuri, R. )

    1993-10-01

    The increase in the UV exposure of the Finnish population associated with the combined effects of ozone depletion and snow reflection was studied with the aid of theoretical calculations based on Green's clear sky UV model. A simple formula was utilized to transform horizontal irradiances to vertical irradiances averaged over 360 degrees azimuth angle. The model was verified with spectral and broadband measurements. The difference between the theoretical and measured UV radiation falling to horizontal surfaces was in most cases less than +/- 10%, and the additional error to theoretical vertical irradiances was less than +/- 10%. The calculations show that the annual horizontal doses in Helsinki (60.2 degrees N, 25 degrees E) are about 35% higher than in Saariselkae (68.4 degrees N, 27.5 degrees E), but the difference is only 16% for vertical doses owing to the stronger contribution to vertical (facial) surfaces of the reflection of UV from snow. At Saariselkae, the maximum vertical irradiance at the end of April approaches the midsummer values. The ozone depletions up to 40% in February and March 1992 had no significant effect on the annual doses because the total ozone returned to normal before the UV increased to biologically significant levels.

  14. Modelling the Impacts of Long-term Changes in Ozone Depleting Substances on Stratospheric Composition

    NASA Astrophysics Data System (ADS)

    Chipperfield, M.; Feng, W.; Dhomse, S.; Hossaini, R.

    2016-12-01

    Long-lived ozone-depleting substances (ODSs), such as chlorofluorocarbons, halons and other gases, are controlled by the Montreal Protocol. Consequently, their atmospheric abundance has started to decline. This has led to a decrease in the overall loading of inorganic chlorine and bromine in the stratosphere and our expectation of recovery of the ozone layer. While observations of atmospheric composition are largely consistent with this picture, there remain some quantitative issues, which are investigated here using multi-decadal simulations of a three-dimensional chemical transport model. For example, atmospheric carbon tetrachloride has been decreasing at a slower rate than expected based on lifetime estimates and known emissions. We use the 3-D model to investigate the impact of uncertainties in the loss process. Also, increases in uncontrolled anthropogenic very short-lived species (VSLS), such as CH2Cl2, may offset some of the decline in chlorine from long-lived species, thereby delaying ozone recovery. We will quantify this impact using the 3-D model. Overall, we will use the model to test the agreement between observed changes in the near-surface abundance of ODSs and changes to stratospheric chlorine and bromine. For example, past studies have noted that variability in stratospheric dynamics (i.e. age of stratospheric air) can complicate the detection of composition trends. Finally, we will use the model to quantify the expected extent of ozone recovery from the combined effect of ODS decreases by late 2016.

  15. Stratospheric ozone depletion due to nitrous oxide: influences of other gases.

    PubMed

    Portmann, R W; Daniel, J S; Ravishankara, A R

    2012-05-05

    The effects of anthropogenic emissions of nitrous oxide (N(2)O), carbon dioxide (CO(2)), methane (CH(4)) and the halocarbons on stratospheric ozone (O(3)) over the twentieth and twenty-first centuries are isolated using a chemical model of the stratosphere. The future evolution of ozone will depend on each of these gases, with N(2)O and CO(2) probably playing the dominant roles as halocarbons return towards pre-industrial levels. There are nonlinear interactions between these gases that preclude unambiguously separating their effect on ozone. For example, the CH(4) increase during the twentieth century reduced the ozone losses owing to halocarbon increases, and the N(2)O chemical destruction of O(3) is buffered by CO(2) thermal effects in the middle stratosphere (by approx. 20% for the IPCC A1B/WMO A1 scenario over the time period 1900-2100). Nonetheless, N(2)O is expected to continue to be the largest anthropogenic emission of an O(3)-destroying compound in the foreseeable future. Reductions in anthropogenic N(2)O emissions provide a larger opportunity for reduction in future O(3) depletion than any of the remaining uncontrolled halocarbon emissions. It is also shown that 1980 levels of O(3) were affected by halocarbons, N(2)O, CO(2) and CH(4), and thus may not be a good choice of a benchmark of O(3) recovery.

  16. Stratospheric ozone depletion due to nitrous oxide: influences of other gases

    PubMed Central

    Portmann, R. W.; Daniel, J. S.; Ravishankara, A. R.

    2012-01-01

    The effects of anthropogenic emissions of nitrous oxide (N2O), carbon dioxide (CO2), methane (CH4) and the halocarbons on stratospheric ozone (O3) over the twentieth and twenty-first centuries are isolated using a chemical model of the stratosphere. The future evolution of ozone will depend on each of these gases, with N2O and CO2 probably playing the dominant roles as halocarbons return towards pre-industrial levels. There are nonlinear interactions between these gases that preclude unambiguously separating their effect on ozone. For example, the CH4 increase during the twentieth century reduced the ozone losses owing to halocarbon increases, and the N2O chemical destruction of O3 is buffered by CO2 thermal effects in the middle stratosphere (by approx. 20% for the IPCC A1B/WMO A1 scenario over the time period 1900–2100). Nonetheless, N2O is expected to continue to be the largest anthropogenic emission of an O3-destroying compound in the foreseeable future. Reductions in anthropogenic N2O emissions provide a larger opportunity for reduction in future O3 depletion than any of the remaining uncontrolled halocarbon emissions. It is also shown that 1980 levels of O3 were affected by halocarbons, N2O, CO2 and CH4, and thus may not be a good choice of a benchmark of O3 recovery. PMID:22451111

  17. Considerations for evaluating ultraviolet radiation-induced genetic damage relative to Antarctic ozone depletion.

    PubMed Central

    Karentz, D

    1994-01-01

    Springtime ozone depletion over the Antarctic results in increased UVB in local marine environments. It has been established that decreases in primary productivity occur with decreases in ozone concentrations, but the impact of increased UVB on the functioning and stability of the ecosystem has not yet been determined. Very little has been done to evaluate the potential for genetic damage caused by the increase in UVB, and this type of damage is most significant relative to the fitness and maintenance of populations. An essential problem in evaluating genotoxic effects is the lack of appropriate techniques to sample and quantify genetic damage in field populations under ambient UVB levels. In addition, it is currently not feasible to estimate exposure levels for organisms in their natural habitats. PMID:7713036

  18. Bromine atom production and chain propagation during springtime Arctic ozone depletion events in Barrow, Alaska

    NASA Astrophysics Data System (ADS)

    Thompson, Chelsea R.; Shepson, Paul B.; Liao, Jin; Huey, L. Greg; Cantrell, Chris; Flocke, Frank; Orlando, John

    2017-03-01

    Ozone depletion events (ODEs) in the Arctic are primarily controlled by a bromine radical-catalyzed destruction mechanism that depends on the efficient production and recycling of Br atoms. Numerous laboratory and modeling studies have suggested the importance of heterogeneous recycling of Br through HOBr reaction with bromide on saline surfaces. On the other hand, the gas-phase regeneration of bromine atoms through BrO-BrO radical reactions has been assumed to be an efficient, if not dominant, pathway for Br reformation and thus ozone destruction. Indeed, it has been estimated that the rate of ozone depletion is approximately equal to twice the rate of the BrO self-reaction. Here, we use a zero-dimensional, photochemical model, largely constrained to observations of stable atmospheric species from the 2009 Ocean-Atmosphere-Sea Ice-Snowpack (OASIS) campaign in Barrow, Alaska, to investigate gas-phase bromine radical propagation and recycling mechanisms of bromine atoms for a 7-day period during late March. This work is a continuation of that presented in Thompson et al. (2015) and utilizes the same model construct. Here, we use the gas-phase radical chain length as a metric for objectively quantifying the efficiency of gas-phase recycling of bromine atoms. The gas-phase bromine chain length is determined to be quite small, at < 1.5, and highly dependent on ambient O3 concentrations. Furthermore, we find that Br atom production from photolysis of Br2 and BrCl, which is predominately emitted from snow and/or aerosol surfaces, can account for between 30 and 90 % of total Br atom production. This analysis suggests that condensed-phase production of bromine is at least as important as, and at times greater than, gas-phase recycling for the occurrence of Arctic ODEs. Therefore, the rate of the BrO self-reaction is not a sufficient estimate for the rate of O3 depletion.

  19. Changes in air quality and tropospheric composition due to depletion of stratospheric ozone and interactions with changing climate: implications for human and environmental health.

    PubMed

    Madronich, S; Shao, M; Wilson, S R; Solomon, K R; Longstreth, J D; Tang, X Y

    2015-01-01

    local scale, ˙OH radicals respond rapidly to changes in UV radiation. However, on large (global) scales, models differ in their predictions by nearly a factor of two, with consequent uncertainties for estimating the atmospheric lifetime and concentrations of key greenhouse gases and air pollutants. Projections of future climate need to consider these uncertainties. No new negative environmental effects of substitutes for ozone depleting substances or their breakdown-products have been identified. However, some substitutes for the ozone depleting substances will continue to contribute to global climate change if concentrations rise above current levels.

  20. Solar ultraviolet radiation and ozone depletion-driven climate change: effects on terrestrial ecosystems.

    PubMed

    Bornman, J F; Barnes, P W; Robinson, S A; Ballaré, C L; Flint, S D; Caldwell, M M

    2015-01-01

    In this assessment we summarise advances in our knowledge of how UV-B radiation (280-315 nm), together with other climate change factors, influence terrestrial organisms and ecosystems. We identify key uncertainties and knowledge gaps that limit our ability to fully evaluate the interactive effects of ozone depletion and climate change on these systems. We also evaluate the biological consequences of the way in which stratospheric ozone depletion has contributed to climate change in the Southern Hemisphere. Since the last assessment, several new findings or insights have emerged or been strengthened. These include: (1) the increasing recognition that UV-B radiation has specific regulatory roles in plant growth and development that in turn can have beneficial consequences for plant productivity via effects on plant hardiness, enhanced plant resistance to herbivores and pathogens, and improved quality of agricultural products with subsequent implications for food security; (2) UV-B radiation together with UV-A (315-400 nm) and visible (400-700 nm) radiation are significant drivers of decomposition of plant litter in globally important arid and semi-arid ecosystems, such as grasslands and deserts. This occurs through the process of photodegradation, which has implications for nutrient cycling and carbon storage, although considerable uncertainty exists in quantifying its regional and global biogeochemical significance; (3) UV radiation can contribute to climate change via its stimulation of volatile organic compounds from plants, plant litter and soils, although the magnitude, rates and spatial patterns of these emissions remain highly uncertain at present. UV-induced release of carbon from plant litter and soils may also contribute to global warming; and (4) depletion of ozone in the Southern Hemisphere modifies climate directly via effects on seasonal weather patterns (precipitation and wind) and these in turn have been linked to changes in the growth of plants

  1. Calculations of increased solar UV fluxes and DUV doses due to stratospheric-ozone depletions

    SciTech Connect

    Zardecki, A.; Gerstl, S.A.W.

    1982-02-01

    Accurate radiative transfer calculations are performed in the middle ultraviolet spectral region for aerosol-loaded atmospheres with the goal of determining the solar irradiance at the ground and quantifying the irradiance perturbations due to the presence of aerosols and various ozone depletions. The extent of the increase of UV-B radiation as a function of wave-length and solar zenith angle is calculated for five model atmospheres. In addition, the damaging ultraviolet dose rates and radiation amplification factors are evaluated at different latitudes and seasons for erythemal and DNA action spectra.

  2. Replacement of ozone depleting and toxic chemicals in gravimetric analysis of non-volatile residue

    NASA Technical Reports Server (NTRS)

    Arnold, G. S.; Uht, J. C.; Sinsheimer, F. B.

    1995-01-01

    The standard tests for determining nonvolatile residue accretion on spacecraft surfaces and in clean processing facilities rely on the use of halogenated solvents that are targeted for elimination because of their toxic or ozone-depleting natures. This paper presents a literature-based screening survey for candidate replacement solvents. Potential replacements were evaluated for their vapor pressure, toxicity, and solvent properties. Three likely candidates were identified: ethyl acetate, methyl acetate, and acetone. Laboratory tests are presented that evaluate the suitability of these candidate replacement solvents.

  3. Arctic chlorine monoxide observations during spring 1993 over Thule, Greenland, and implications for ozone depletion

    NASA Technical Reports Server (NTRS)

    Shindell, D. T.; Reeves, J. M.; Emmons, L. K.; De Zafra, R. L.

    1994-01-01

    We have determined the vertical distribution of chlorine monoxide (ClO), from measurements of pressure-broadened molecular-emission spectra made over Thule, Greenland, during the 1993 Arctic spring. The measurements show a weak lower stratospheric layer of chlorine monoxide inside the vortex in late February, which was, however, significantly greater in mixing ratio than that seen in observations we made in the spring of 1992. ClO was also observed in much smaller quantities in early to mid-March 1993 when Thule was outside the vortex. The amount of ClO within the vortex was severely reduced by the time it returned over Thule in late March. This reduction occurred several weeks earlier relative to the winter solstice than the decline of ClO inside the Antarctic vortex in 1993. The enhanced Arctic lower stratospheric layer seen in late February 1993 at a nearly equivalent photochemical period, and beyond. We have calculated daily ozone loss rates, due primarily to the dimer chlorine catalytic cycle, from both sets of measurements. The vertical integral of the Arctic daily percentage ozone loss when the largest ClO levels were present, at the end of February, is found to be approximately one quarter of that in the Antarctic at a photochemical period only 1 week later. The relative weakness of daily ozone depletion, combined with the early disappearance of ClO in the Arctic, suggests that hemispheric dilution by ozone-poor air from within the Arctic vortex is unlikely to be sufficient to explain the historically extreme loss of midlatitude northern hemisphere ozone which began in 1992 and persisted throughout 1993.

  4. Arctic chlorine monoxide observations during spring 1993 over Thule, Greenland, and implications for ozone depletion

    NASA Technical Reports Server (NTRS)

    Shindell, D. T.; Reeves, J. M.; Emmons, L. K.; De Zafra, R. L.

    1994-01-01

    We have determined the vertical distribution of chlorine monoxide (ClO), from measurements of pressure-broadened molecular-emission spectra made over Thule, Greenland, during the 1993 Arctic spring. The measurements show a weak lower stratospheric layer of chlorine monoxide inside the vortex in late February, which was, however, significantly greater in mixing ratio than that seen in observations we made in the spring of 1992. ClO was also observed in much smaller quantities in early to mid-March 1993 when Thule was outside the vortex. The amount of ClO within the vortex was severely reduced by the time it returned over Thule in late March. This reduction occurred several weeks earlier relative to the winter solstice than the decline of ClO inside the Antarctic vortex in 1993. The enhanced Arctic lower stratospheric layer seen in late February 1993 at a nearly equivalent photochemical period, and beyond. We have calculated daily ozone loss rates, due primarily to the dimer chlorine catalytic cycle, from both sets of measurements. The vertical integral of the Arctic daily percentage ozone loss when the largest ClO levels were present, at the end of February, is found to be approximately one quarter of that in the Antarctic at a photochemical period only 1 week later. The relative weakness of daily ozone depletion, combined with the early disappearance of ClO in the Arctic, suggests that hemispheric dilution by ozone-poor air from within the Arctic vortex is unlikely to be sufficient to explain the historically extreme loss of midlatitude northern hemisphere ozone which began in 1992 and persisted throughout 1993.

  5. The Severe Arctic Ozone Depletion 2010/11 - Implications for UV Radiation in Europe and North America

    NASA Astrophysics Data System (ADS)

    von Hobe, M.; Griessbach, S.; Wegner, T.

    2011-12-01

    The Arctic winter 2010/11 saw record ozone depletion in the northern polar vortex with column ozone dropping below 250 DU by the end of the winter. One question of concern is, how strongly such a winter affects surface UV radiation in high and mid-latitudes and in particular in central Europe and North America. This obviously depends not only on the degree of ozone depletion but also on the spatial extent and the position of the depleted vortex. Besides, surface UV levels are influenced by other factors such as cloudiness, aerosol loading and variations in the solar flux. Here, monthly average as well as maximum erythemal UV doses are calculated for spring and early summer over different regions in Europe and North America for Arctic winters between 1980 and 2011, using data from the Ozone Monitoring Instrument (OMI) onboard the EOS Aura satellite and the Total Ozone Mapping Spectrometer onboard Nimbus-7, Meteor-3 and Earth-Probe. The comparison of UV data from Arctic winters with very different degrees of polar vortex ozone loss allows to estimate the extent, to which large vortex ozone losses translate directly into higher surface UV in certain areas in high and mid-latitudes. Special attention is given to the 2010/11 winter.

  6. Studies of Arctic Tropospheric Ozone Depletion Events Through Buoy-Borne Observations and Laboratory Studies

    NASA Astrophysics Data System (ADS)

    Halfacre, John W.

    The photochemically-induced destruction of ground-level Arctic ozone in the Arctic occurs at the onset of spring, in concert with polar sunrise. Solar radiation is believed to stimulate a series of reactions that cause the production and release of molecular halogens from frozen, salty surfaces, though this mechanism is not yet well understood. The subsequent photolysis of molecular halogens produces reactive halogen atoms that remove ozone from the atmosphere in these so-called "Ozone Depletion Events" (ODEs). Given that much of the Arctic region is sunlit, meteorologically stable, and covered by saline ice and snow, it is expected that ODEs could be a phenomenon that occurs across the entire Arctic region. Indeed, an ever-growing body of evidence from coastal sites indicates that Arctic air masses devoid of O3 most often pass over sea ice-covered regions before arriving at an observation site, suggesting ODE chemistry occurs upwind over the frozen Arctic Ocean. However, outside of coastal observations, there exist very few long-term observations from the Arctic Ocean from which quantitative assessments of basic ODE characteristics can be made. This work presents the interpretation of ODEs through unique chemical and meteorological observations from several ice-tethered buoys deployed around the Arctic Ocean. These observations include detection of ozone, bromine monoxide, and measurements of temperature, relative humidity, atmospheric pressure, wind speed, and wind direction. To assess whether the O-Buoys were observing locally based depletion chemistry or the transport of ozone-poor air masses, periods of ozone decay were interpreted based on current understanding of ozone depletion kinetics, which are believed to follow a pseudo-first order rate law. In addition, the spatial extents of ODEs were estimated using air mass trajectory modeling to assess whether they are a localized or synoptic phenomenon. Results indicate that current understanding of the

  7. Temporal and spatial characteristics of surface ozone depletion events from measurements over the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Halfacre, J. W.; Knepp, T. N.; Stephens, C. R.; Pratt, K. A.; Shepson, P.; Simpson, W. R.; Peterson, P. K.; Walsh, S. J.; Matrai, P. A.; Bottenheim, J. W.; Netcheva, S.; Perovich, D. K.; Richter, A.

    2012-12-01

    Arctic tropospheric ozone depletion events (ODEs) have been studied primarily from coastal sites since the mid 1980s with only a few studies occurring over the Arctic Ocean, the hypothesized site of initiation. Despite a multitude of studies, some basic characteristics of ODEs remain poorly defined, including their temporal, spatial, and meteorological characteristics. Several deployments of autonomous, ice-tethered buoys (O-Buoys) were used to elucidate such characteristics from both the Arctic Ocean and coastal sites. The apparent first order decays imply an ozone lifetime (median of 11 hours) that would correspond to a very large BrO concentration, relative to BrO observations obtained from the buoys. These results suggest that ODEs involve a large, unaccounted for source of bromine atoms, that there is a significant contribution from other mechanisms possibly not involving bromine, or that the majority of observed ODEs represent advection of previously-depleted air to the buoy site, even in the Arctic Ocean. Using backward air mass trajectories, the spatial scales for ODEs (defined by time periods with O3 ≤ 15 nmol/mol) were estimated to be ~1800 km (mode), suggesting that most of the lower troposphere above the Arctic Ocean is frequently, at least partially, depleted of ozone. Using the same method, areas estimated to be highly depleted of O3 (< 10 nmol/mol) had dimensions of ~200-600 km (mode). These events correlate with areas of enhanced column BrO from GOME satellite measurements. These observations point to a heterogeneous boundary layer with localized regions of active, O3-destroying halogen chemistry, interspersed among larger regions of previously depleted air that retain their chemical composition due to a lack of mixing. O-Buoy measurements showed low local wind speed averages during most ODEs (mode of 4 m/s), and no apparent dependence on local temperatures. The ice-tethered O-Buoys provide unique data to study the characteristics of ODEs; however

  8. Widespread persistent near-surface ozone depletion at northern high latitudes in spring

    NASA Astrophysics Data System (ADS)

    Zeng, Tao; Wang, Yuhang; Chance, Kelly; Browell, Edward V.; Ridley, Brian A.; Atlas, Elliot L.

    2003-12-01

    Springtime near-surface ozone depletion has been observed at northern high latitudes. Due to limited observations, the spatial and temporal extent of low O3 concentrations near the surface is still unknown. A regional 3-D chemistry and transport model is applied to simulate surface O3 depletion catalyzed by bromine radicals at northern high latitudes in March and April 2000. Satellite observations of BrO column by the ESA Global Ozone Monitoring Experiment (GOME) were processed to specify the BrO concentrations in the lower troposphere. In view of the GOME measurement and model uncertainties, the model results show an adequate agreement with the O3 depletion events observed at two surface sites, Alert, Canada (82.5°N, 62.3°W) and Barrow, Alaska (71.3°N, 156.6°W), and by airborne in situ and DIAL instrument during the TOPSE experiments at northern high latitudes. Low O3 events at Alert appear to be mostly driven by transport of O3-poor air from high BrO regions. Model results indicate that low O3 concentrations (<20 ppbv) near the surface cover ~60% of the northern high latitudes and that the depleted O3 concentrations (<10 ppbv) cover ~20% of the region in April. The high BrO events tend to be large-scale and persistent (1-2 weeks). We find that they are correlated with low temperature, a condition conducive for heterogeneous reactions on frozen snow or aerosol surfaces.

  9. Greenhouse gas impacts of declining hydrocarbon resource quality: Depletion, dynamics, and process emissions

    NASA Astrophysics Data System (ADS)

    Brandt, Adam Robert

    This dissertation explores the environmental and economic impacts of the transition to hydrocarbon substitutes for conventional petroleum (SCPs). First, mathematical models of oil depletion are reviewed, including the Hubbert model, curve-fitting methods, simulation models, and economic models. The benefits and drawbacks of each method are outlined. I discuss the predictive value of the models and our ability to determine if one model type works best. I argue that forecasting oil depletion without also including substitution with SCPs results in unrealistic projections of future energy supply. I next use information theoretic techniques to test the Hubbert model of oil depletion against five other asymmetric and symmetric curve-fitting models using data from 139 oil producing regions. I also test the assumptions that production curves are symmetric and that production is more bell-shaped in larger regions. Results show that if symmetry is enforced, Gaussian production curves perform best, while if asymmetry is allowed, asymmetric exponential models prove most useful. I also find strong evidence for asymmetry: production declines are consistently less steep than inclines. In order to understand the impacts of oil depletion on GHG emissions, I developed the Regional Optimization Model for Emissions from Oil Substitutes (ROMEO). ROMEO is an economic optimization model of investment and production of fuels. Results indicate that incremental emissions (with demand held constant) from SCPs could be 5-20 GtC over the next 50 years. These results are sensitive to the endowment of conventional oil and not sensitive to a carbon tax. If demand can vary, total emissions could decline under a transition because the higher cost of SCPs lessens overall fuel consumption. Lastly, I study the energetic and environmental characteristics of the in situ conversion process, which utilizes electricity to generate liquid hydrocarbons from oil shale. I model the energy inputs and outputs

  10. The increase of Southern Ocean winds and SAM: is it caused by the ozone hole or by increased greenhouse gases?

    NASA Astrophysics Data System (ADS)

    Roscoe, H. K.

    2010-12-01

    The amplitude of the Southern Annular Mode of variability in sea level pressure has increased significantly since station records began in the late 1950s. As expected, this has led to an increase in surface winds over the Southern Ocean in meteorological analyses. Roscoe & Haigh (2007), using data to 2006, showed that the increase in SAM correlated at high significance with both the ozone hole and the increase in greenhouse gases, but the correlation with the ozone hole was more significant. However, it was difficult to quantify the meaning of this greater significance because of the then similarity between the trends in greenhouse gases and the ozone hole - the esoteric statistical concepts associated with the Akaike Information Criterion had to be used. Now the trends have diverged significantly, so the update presented here allows us to quantify the greater degree of significance of the ozone hole, using the more familiar statistical method of Student’s t-test.

  11. [Plant reaction to elevated ultraviolet irradiation: potential impacts of stratospheric ozone depletion].

    PubMed

    Strzhizhovskiĭ, A D

    1999-01-01

    The ozone layer depletion evokes the increase of solar UV-B radiation intensity and corresponding reductions of growth (height, leaf area, fresh and dry weight), photosynthetic activity and flowering in higher plants. Competitive interactions also may be altered indirectly by differential growth responses. The UV-B-sensitivity of plants varies both among species and among cultivars of a given species. Photosynthetic activity may be reduced by direct effects on the photosynthetic process or metabolic pathways, or indirectly through effects on photosynthetic pigments or stomatal function. Plants may also respond by accumulating UV-absorbing compounds in their outer tissue layers, which presumably protect sensitive target from UV-damage. The key enzymes in the biosynthetic pathways of these compounds are specifically induced by UV-B irradiation via gene activation. The effects of UV-B radiation on plants can be modified by prevailing microclimatic conditions. Plants tend to be less sensitive to UV-B under drought or mineral deficiency, while sensitivity increases under low levels of visible light. Prognoses of agricultural yield reduction and economic loss for different scenarious of stratospheric ozone depletion are presented.

  12. Uncertainty analysis of projections of ozone-depleting substances: mixing ratios, EESC, ODPs, and GWPs

    NASA Astrophysics Data System (ADS)

    Velders, G. J. M.; Daniel, J. S.

    2014-03-01

    The rates at which ozone-depleting substances (ODSs) are removed from the atmosphere, which determine the lifetimes of these ODSs, are key factors for determining the rate of ozone layer recovery in the coming decades. We present here a comprehensive uncertainty analysis of future mixing ratios of ODSs, levels of equivalent effective stratospheric chlorine (EESC), ozone depletion potentials, and global warming potentials (GWPs), using, among other information, the 2013 WCRP/SPARC (World Climate Research Programme/Stratospheric Processes and their Role in Climate) assessment of lifetimes of ODSs and their uncertainties. The year EESC returns to pre-1980 levels, a metric commonly used to indicate a level of recovery from ODS-induced ozone depletion, is 2048 for midlatitudes and 2075 for Antarctic conditions based on the lifetimes from the SPARC assessment, which is about 2 and 4 yr, respectively, later than based on the lifetimes from the WMO (World Meteorological Organization) assessment of 2011. However, the uncertainty in this return to 1980 levels is much larger than the shift due to this change in lifetimes. The year EESC returns to pre-1980 levels ranges from 2039 to 2064 (95% confidence interval) for midlatitudes and from 2061 to 2105 for the Antarctic spring. The primary contribution to these ranges comes from the uncertainty in the lifetimes, with smaller contributions from uncertainties in other modeled parameters. The earlier years of the return estimates derived by the uncertainty analysis, i.e., 2039 for midlatitudes and 2061 for Antarctic spring, are comparable to a hypothetical scenario in which emissions of ODSs cease in 2014. The later end of the range, i.e., 2064 for midlatitudes and 2105 for Antarctic spring, can also be obtained by a scenario with an additional emission of about 7 Mt CFC-11 eq. (eq. - equivalent) in 2015, which is the same as about 2 times the projected cumulative anthropogenic emissions of all ODSs from 2014 to 2050, or about 12

  13. The ozone depletion potentials on halocarbons: Their dependence of calculation assumptions

    NASA Technical Reports Server (NTRS)

    Karol, Igor L.; Kiselev, Andrey A.

    1994-01-01

    The concept of Ozone Depletion Potential (ODP) is widely used in the evaluation of numerous halocarbons and of their replacement effects on ozone, but the methods, assumptions and conditions used in ODP calculations have not been analyzed adequately. In this paper a model study of effects on ozone of the instantaneous releases of various amounts of CH3CCl3 and of CHF2Cl (HCFC-22) for several compositions of the background atmosphere are presented, aimed at understanding connections of ODP values with the assumptions used in their calculations. To facilitate the ODP computation in numerous versions for the long time periods after their releases, the above rather short-lived gases and the one-dimensional radiative photochemical model of the global annually averaged atmospheric layer up to 50 km height are used. The variation of released gas global mass from 1 Mt to 1 Gt leads to ODP value increase with its stabilization close to the upper bound of this range in the contemporary atmosphere. The same variations are analyzed for conditions of the CFC-free atmosphere of 1960's and for the anthropogenically loaded atmosphere in the 21st century according to the known IPCC 'business as usual' scenario. Recommendations for proper ways of ODP calculations are proposed for practically important cases.

  14. The effect of depletion of the earth ozone layer on the human health condition.

    PubMed

    Jankowski, J; Cader, A B

    1997-01-01

    Development of economic human activity has caused many harmful side effects which constitute an important danger for the biological life of our planet. This review discusses some aspects of the atmospheric changes and their influence on UV radiation reaching a man. The ozone-layer depletion is the result of emissions to the atmosphere chemical substances containing chlorine and bromine. Ozone, which absorbs the solar ultraviolet radiation, is a basic bio-protective filter. Degradation of the atmospheric ozone layer leads to increase of UV-level in our environment. The harmful effects of UV-radiation on live organisms constitute a danger for health of the whole human population. There is no doubt that cumulative exposure to UV radiation is important in the aetiology of skin cancer. A strong cataractogenic effect of UV radiation has been also evidenced. It is also known that the increase of UV radiation may be capable of activating viruses and reduce immunological response. The recent and predicted increase in these menaces are discussed.

  15. Interactive Photochemistry in Earth System Models to Assess Uncertainty in Ozone and Greenhouse Gases. Final report

    SciTech Connect

    Prather, Michael J.; Hsu, Juno; Nicolau, Alex; Veidenbaum, Alex; Smith, Philip Cameron; Bergmann, Dan

    2014-11-07

    Atmospheric chemistry controls the abundances and hence climate forcing of important greenhouse gases including N2O, CH4, HFCs, CFCs, and O3. Attributing climate change to human activities requires, at a minimum, accurate models of the chemistry and circulation of the atmosphere that relate emissions to abundances. This DOE-funded research provided realistic, yet computationally optimized and affordable, photochemical modules to the Community Earth System Model (CESM) that augment the CESM capability to explore the uncertainty in future stratospheric-tropospheric ozone, stratospheric circulation, and thus the lifetimes of chemically controlled greenhouse gases from climate simulations. To this end, we have successfully implemented Fast-J (radiation algorithm determining key chemical photolysis rates) and Linoz v3.0 (linearized photochemistry for interactive O3, N2O, NOy and CH4) packages in LLNL-CESM and for the first time demonstrated how change in O2 photolysis rate within its uncertainty range can significantly impact on the stratospheric climate and ozone abundances. From the UCI side, this proposal also helped LLNL develop a CAM-Superfast Chemistry model that was implemented for the IPCC AR5 and contributed chemical-climate simulations to CMIP5.

  16. Quantification of the depletion of ozone in the plume of Mount Etna

    NASA Astrophysics Data System (ADS)

    Surl, L.; Donohoue, D.; Aiuppa, A.; Bobrowski, N.; von Glasow, R.

    2015-03-01

    Volcanoes are an important source of inorganic halogen species into the atmosphere. Chemical processing of these species generates oxidised, highly reactive, halogen species which catalyse considerable O3 destruction within volcanic plumes. A campaign of ground-based in situ O3, SO2 and meteorology measurements was undertaken at the summit of Mount Etna volcano in July/August 2012. At the same time, spectroscopic measurements were made of BrO and SO2 columns in the plume downwind. Depletions of ozone were seen at all in-plume measurement locations, with average O3 depletions ranging from 11-35 nmol mol-1 (15-45%). Atmospheric processing times of the plume were estimated to be between 1 and 4 min. A 1-D numerical model of early plume evolution was also used. It was found that in the early plume O3 was destroyed at an approximately constant rate relative to an inert plume tracer. This is ascribed to reactive halogen chemistry, and the data suggests the majority of the reactive halogen that destroys O3 in the early plume is generated within the crater, including a substantial proportion generated in a high-temperature "effective source region" immediately after emission. The model could approximately reproduce the main measured features of the ozone chemistry. Model results show a strong dependence of the near-vent bromine chemistry on the presence or absence of volcanic NOx emissions and suggest that near-vent ozone measurements can be used as a qualitative indicator of NOx emission.

  17. 78 FR 24997 - Protection of Stratospheric Ozone: Listing of Substitutes for Ozone-Depleting Substances-Fire...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-29

    ... stratospheric ozone layer. This action will provide users that need specialized fire protection applications... information on SNAP, refer to EPA's Ozone Layer Protection Web site at www.epa.gov/ozone/snap/index.html . For... impact on the ozone layer or climate. The physicochemical properties of the majority of halon...

  18. International cooperation in protection of atmospheric ozone: the Montreal Protocol on substances that deplete the ozone layer. Leonard v. B. Sutton award paper

    SciTech Connect

    Blegen, B.

    1988-01-01

    On September 14, 1987, in Montreal, Canada, 24 countries signed a landmark Protocol to the Vienna Convention for the Protection of the Ozone Layer, thereby taking a large step toward solution of the global environmental problem posed by the depletion of atmospheric ozone. The importance of this Protocol is two-fold: it serves to reduce the production of pollutants responsible for atmospheric ozone destruction, and it represents a milestone in the field of international environmental cooperation. By focusing on both these aspects of the Protocol, this article attempts to provide a thorough analysis of the ozone problem. After a summary of the scientific background of the current threat to atmospheric ozone, the article discusses the Protocol's historical background, analyzes its provisions, and highlights its significance for the field of international environmental law in general. It is hoped that this discussion will serve to demonstrate just how unique and revolutionary the Protocol is, as well as emphasize the scope and severity of the problem of atmospheric ozone depletion. 111 references.

  19. Terrestrial ozone depletion due to a Milky Way gamma-ray burst

    NASA Astrophysics Data System (ADS)

    Thomas, Brian C.

    Gamma-Ray Bursts (GRBs) are short, incredibly powerful astrophysical events which produce a flux of radiation detectable across the observable universe. A GRB within our own galaxy could cause major damage to the Earth's biosphere. Rate estimates suggest that at least one GRB has occurred within a dangerous range (about 2 kpc) in the last billion years. The gamma radiation from such a burst would quickly deplete much of the Earth's protective ozone layer, allowing an increase in solar UVB radiation reaching the surface. This radiation is harmful to life, causing sunburn and damaging DNA. In addition, NO 2 produced in the atmosphere would cause a decrease in visible sunlight reaching the surface and could cause global cooling. Nitric acid rain could stress portions of the biosphere, but the increased nitrate deposition could be helpful to land plants. We have used a two-dimensional atmospheric model to investigate the effects on the Earth's atmosphere of a GRB. We have simulated bursts delivering a range of fluences, at various latitudes, at the equinoxes and solstices, and at different times of day. We have computed DNA damage caused by increased solar UVB radiation, reduction in solar visible light due to NO 2 opacity; and deposition of nitrates through rainout of HNO 3 . For a "typical" burst in the last billion years, we find globally averaged ozone depletion up to 38%. Localized depletion reaches as much as 74%. Significant global depletion (at least 10%) persists up to about 7 years after the burst. Our results depend strongly on time of year and latitude over which the burst occurs. We find DNA damage of up to 16 times the normal annual global average, with greatest damage occurring at low to mid latitudes. We find reductions in visible sunlight of a few percent, primarily in the polar regions. Nitrate deposition similar to or slightly greater than that currently caused by lightning is also observed. We find support in our results for the hypothesis that the

  20. The human health effects of ozone depletion and interactions with climate change.

    PubMed

    Norval, M; Lucas, R M; Cullen, A P; de Gruijl, F R; Longstreth, J; Takizawa, Y; van der Leun, J C

    2011-02-01

    Depletion of the stratospheric ozone layer has led to increased solar UV-B radiation (280-315 nm) at the surface of the Earth. This change is likely to have had an impact on human exposure to UV-B radiation with consequential detrimental and beneficial effects on health, although behavioural changes in society over the past 60 years or so with regard to sun exposure are of considerable importance. The present report concentrates on information published since our previous report in 2007. The adverse effects of UV radiation are primarily on the eye and the skin. While solar UV radiation is a recognised risk factor for some types of cataract and for pterygium, the evidence is less strong, although increasing, for ocular melanoma, and is equivocal at present for age-related macular degeneration. For the skin, the most common harmful outcome is skin cancer, including melanoma and the non-melanoma skin cancers, basal cell carcinoma and squamous cell carcinoma. The incidence of all three of these tumours has risen significantly over the past five decades, particularly in people with fair skin, and is projected to continue to increase, thus posing a significant world-wide health burden. Overexposure to the sun is the major identified environmental risk factor in skin cancer, in association with various genetic risk factors and immune effects. Suppression of some aspects of immunity follows exposure to UV radiation and the consequences of this modulation for the immune control of infectious diseases, for vaccination and for tumours, are additional concerns. In a common sun allergy (polymorphic light eruption), there is an imbalance in the immune response to UV radiation, resulting in a sun-evoked rash. The major health benefit of exposure to solar UV-B radiation is the production of vitamin D. Vitamin D plays a crucial role in bone metabolism and is also implicated in protection against a wide range of diseases. Although there is some evidence supporting protective effects

  1. Environmental effects of ozone depletion and its interactions with climate change: progress report, 2015.

    PubMed

    2016-02-01

    The Environmental Effects Assessment Panel (EEAP) is one of three Panels that regularly informs the Parties (countries) to the Montreal Protocol on the effects of ozone depletion and the consequences of climate change interactions with respect to human health, animals, plants, biogeochemistry, air quality, and materials. The Panels provide a detailed assessment report every four years. The most recent 2014 Quadrennial Assessment by the EEAP was published as a special issue of seven papers in 2015 (Photochem. Photobiol. Sci., 2015, 14, 1-184). The next Quadrennial Assessment will be published in 2018/2019. In the interim, the EEAP generally produces an annual update or progress report of the relevant scientific findings. The present progress report for 2015 assesses some of the highlights and new insights with regard to the interactive nature of the effects of UV radiation, atmospheric processes, and climate change.

  2. Arctic tropospheric ozone depletion during spring 2008 : Source regions and transport

    NASA Astrophysics Data System (ADS)

    Koo, J.; Wang, Y.; Choi, S.; Kurosu, T. P.; Chance, K.; Weinheimer, A. J.; Ryerson, T. B.; Oltmans, S. J.; Hair, J. W.

    2009-12-01

    Ozone depletion events (ODEs) during the ARCTAS and ARCPAC experiments in spring 2008 are analyzed using backtrajectory analysis with meteorological fields simulated by the polar version of MM5. Satellite observations of BrO by OMI and GOME2 instruments are also used. We identify two common ODE source regions in the Canadian archipelagoes and north of Alaska and Siberia. The vertical distribution of backtrajectories indicates that ODEs occur mainly in the lower atmosphere. Correlation analysis suggests that ODEs at Barrow are more transport-driven than those at Alert. The combination of NASA DC-8 and NOAA WP-3D in situ observations implies a large gradient of BrO within a relatively small spatial scale; this feature was not apparent in satellite BrO measurements. The backtrajectory analysis also identifies a region with a high probability of enhanced BrO concentrations, contrary to satellite observations.

  3. Use of ozone-depleting substances; removal of essential-use designation (flunisolide, etc.). Final rule.

    PubMed

    2010-04-14

    The Food and Drug Administration (FDA), after consultation with the Environmental Protection Agency (EPA), is amending FDA's regulation on the use of ozone-depleting substances (ODSs) in self-pressurized containers to remove the essential-use designations for flunisolide, triamcinolone, metaproterenol, pirbuterol, albuterol and ipratropium in combination, cromolyn, and nedocromil used in oral pressurized metered-dose inhalers (MDIs). The Clean Air Act requires FDA, in consultation with the EPA, to determine whether an FDA-regulated product that releases an ODS is an essential use of the ODS. FDA has concluded that there are no substantial technical barriers to formulating flunisolide, triamcinolone, metaproterenol, pirbuterol, albuterol and ipratropium in combination, cromolyn, and nedocromil as products that do not release ODSs, and therefore they will no longer be essential uses of ODSs as of the effective dates of this rule. MDIs for these active moieties containing an ODS may not be marketed after the relevant effective date.

  4. Emission location dependent ozone depletion potentials for very short-lived halogenated species

    NASA Astrophysics Data System (ADS)

    Pisso, I.; Haynes, P. H.; Law, K. S.

    2010-06-01

    We present trajectory-based estimates of Ozone Depletion Potentials (ODPs) for very short-lived halogenated source gases as a function of surface emission location. The ODPs are determined by the fraction of source gas and its degradation products which reach the stratosphere, depending primarily on tropospheric transport and chemistry, and the effect of the resulting reactive halogen in the stratosphere, which is determined by stratospheric transport and chemistry, in particular by stratospheric residence time. Reflecting the different timescales and physico-chemical processes in the troposphere and stratosphere, the estimates are based on calculation of separate ensembles of trajectories for the troposphere and stratosphere. A methodology is described by which information from the two ensembles can be combined to give the ODPs. The ODP estimates for a species with a 20 d lifetime, representing a compound like n-propyl bromide, are presented as an example. The estimated ODPs show strong geographical and season variation, particularly within the tropics. The values of the ODPs are sensitive to the inclusion of a convective parametrization in the trajectory calculations, but the relative spatial and seasonal variation is not. The results imply that ODPs are largest for emissions from South and South-East Asia during Northern Hemisphere summer and from the Western Pacific during Northern Hemisphere winter. Large ODPs are also estimated for emissions throughout the tropics with also non-negligible values extending into northern mid-latitudes particularly in the summer. These first estimates, which include some simplifying assumptions, show larger ODP values than previous studies, particularly over Southern Asia, suggesting that emissions of short-lived halogen source gases in certain geographical regions could have a significant impact on stratospheric ozone depletion.

  5. Ozone depletion due to the use of chlorofluorocarbon: Government and industry response. (Latest citations from the BioBusiness database). Published Search

    SciTech Connect

    1996-03-01

    The bibliography contains citations concerning the response of business and government to atmospheric ozone depletion. Voluntary restrictions in the use of chlorofluorocarbons by industry and attempts to develop a substitute are examined. References cite studies of the ozone layer and the effects of aerosols worldwide, and examples of climatic models of ozone depletion. Government sponsored bans on chloroflourocarbons are examined. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  6. Ozone depletion due to the use of chlorofluorocarbon: government and industry response. January 1985-March 1989 (Citations from the Biobusiness Database). Report for January 1985-March 1989

    SciTech Connect

    Not Available

    1989-04-01

    This bibliography contains citations concerning the response of business and government to atomospheric ozone depletion. Industrial concern expressed by voluntary restrictions in the use of chlorofluorocarbons and the search for a substitute is presented. Studies of the ozone layer and the effects of aerosols worldwide are presented. Climatic response to ozone depletion is included. Government sponsored bans on chloroflourocarbons are examined. (Contains 142 citations fully indexed and including a title list.)

  7. Ozone depletion due to the use of chlorofluorocarbon: Government and industry response. (Latest citations from the Biobusiness data base). Published Search

    SciTech Connect

    Not Available

    1992-05-01

    The bibliography contains citations concerning the response of business and government to atmospheric ozone depletion. Voluntary restrictions in the use of chlorofluorocarbons by industry and attempts to develop a substitute are examined. References cite studies of the ozone layer and the effects of aerosols worldwide, and examples of climatic models of ozone depletion. Government sponsored bans on chloroflourocarbons are examined. (Contains 250 citations and includes a subject term index and title list.)

  8. Power and knowledge in international environmental politics: The case of stratospheric ozone depletion

    SciTech Connect

    Litfin, K.T.

    1992-01-01

    Most analyses of science in world politics suffer from the modern misreading of the relationship between knowledge and power. The availability of scientific knowledge to the relevant decision makers was a necessary condition for the negotiation of the Montreal Protocol on Substances that Deplete the Ozone Layer, but it was far from being a sufficient one. The power of science was a function of the political context in which it was debated, a context which was defined substantially by the discovery of the Antarctic ozone hole.' The prominence of knowledge-based power in at least some situations means that conventional materialist notions of power should be expanded to include a more discursive and productive conception of power. Environmental problems are not merely physical events, but informational phenomena. A case study methodology is used to develop an interactive conception of power and knowledge. A detailed study of the Montreal Protocol is offered, as well as less detailed studies of the international policy processes for acid rain and global climate change.

  9. 75 FR 19213 - Use of Ozone-Depleting Substances; Removal of Essential-Use Designation (Flunisolide, etc.)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-14

    ...The Food and Drug Administration (FDA), after consultation with the Environmental Protection Agency (EPA), is amending FDA's regulation on the use of ozone-depleting substances (ODSs) in self- pressurized containers to remove the essential-use designations for flunisolide, triamcinolone, metaproterenol, pirbuterol, albuterol and ipratropium in combination, cromolyn, and nedocromil used in oral......

  10. Kindergarten Teachers' Conceptual Framework on the Ozone Layer Depletion. Exploring the Associative Meanings of a Global Environmental Issue

    ERIC Educational Resources Information Center

    Daskolia, Maria; Flogaitis, Evgenia; Papageorgiou, Evgenia

    2006-01-01

    This paper reports on a study conducted among Greek kindergarten teachers aiming to explore their conceptual frameworks on a major environmental issue of our times: the ozone layer depletion. The choice of this particular issue was premised on its novelty, complexity and abstractness which present teachers with difficulties in its teaching. A free…

  11. Kindergarten Teachers' Conceptual Framework on the Ozone Layer Depletion. Exploring the Associative Meanings of a Global Environmental Issue

    ERIC Educational Resources Information Center

    Daskolia, Maria; Flogaitis, Evgenia; Papageorgiou, Evgenia

    2006-01-01

    This paper reports on a study conducted among Greek kindergarten teachers aiming to explore their conceptual frameworks on a major environmental issue of our times: the ozone layer depletion. The choice of this particular issue was premised on its novelty, complexity and abstractness which present teachers with difficulties in its teaching. A free…

  12. 21 CFR 2.125 - Use of ozone-depleting substances in foods, drugs, devices, or cosmetics.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., devices, or cosmetics. 2.125 Section 2.125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Specific Products Subject to the Federal Food, Drug, and Cosmetic Act § 2.125 Use of ozone-depleting substances in foods, drugs, devices, or cosmetics. Link to an amendment published at 73 FR 69552, Nov....

  13. Ozone depletion in filaments of the Arctic Polar Vortex observed during the first Global Hawk UAS science mission

    NASA Astrophysics Data System (ADS)

    Elkins, J. W.; Hintsa, E. J.; Dutton, G. S.; Hall, B. D.; Moore, F. L.; Gao, R.; Oltmans, S. J.; Patrick, L.; Johnson, B. J.; Ray, E. A.; Nance, D.; Fahey, D. W.; Newman, P. A.

    2011-12-01

    One of the important potential uses of the NASA Global Hawk Unmanned Aircraft System (UAS) in scientific research is to study stratospheric ozone (O3) depletion in polar regions. Manned flights involve remote and hazardous duty, which pose great risks to pilots, crew, and scientists. Arctic ozone depletion observed in the spring of 2010 by satellites, manned aircraft campaigns, ground-base stations was less severe than that observed this year (2011). The Global Hawk UAS flight on 23 April 2010 was the first to observe ozone-depleted air with a UAS platform. Temperatures in the polar vortex were cold enough for Type II Polar Stratospheric Clouds (PSC) to form for a short period (days) at 50 hPa in 2010, and cold temperatures existed for almost 2 months for Type I PSC formation. Based on the NOAA Unmanned aircraft systems Chromatograph for Atmospheric Trace Species (UCATS) ozone versus nitrous oxide tracer correlation plot (below), there is 21% less ozone in air from a polar filament sampled on 7 April 2010 compared to the Arctic air sampled later on 23 April 2010. The NOAA UAS Fast Ozone Instrument showed a similar pattern with respect to N2O. Age-of-air values derived from on board SF6 observations were about 5 years in the filament versus about 3 years outside the filament in the subsequent polar flight. The Global Hawk UAS flights were part of the Global Hawk Pacific Experiment (GloPac), which demonstrated flights up to 28.6 hr duration, altitudes as high as 19.8 km and a maximum range of 9200 nm while carrying a payload of in situ and remote instrumentation for atmospheric chemical and aerosol tracers. This first science mission of the NASA Global Hawk UAS demonstrated its huge potential for stratospheric ozone research over remote and hazardous polar areas.

  14. Simulation and causes of eastern Antarctica surface cooling related to ozone depletion during austral summer in FGOALS-s2

    NASA Astrophysics Data System (ADS)

    Yang, Jing; Bao, Qing; Ji, Duoying; Gong, Daoyi; Mao, Rui; Zhang, Ziyin; Kim, Seong-Joong

    2014-09-01

    Two parallel sets of numerical experiments (an ozone-hole simulation and a non-ozone-hole simulation) were performed to investigate the effect of ozone depletion on surface temperature change using the second spectral version of the Flexible Global Ocean-Atmosphere-Land System model (FGOALS-s2), focusing on the eastern Antarctica (EA) continent in austral summer. First, we evaluated the ability of the model to simulate the EA surface cooling, and found the model can successfully reproduce the cooling trend of the EA surface, as well as the circulation change circling the South Pole in the past 30 years. Second, we compared the two experiments and discovered that the ozone depletion causes the cooling trend and strengthens the circumpolar westerly flow. We further investigated the causes of the EA surface cooling associated with the ozone hole and found two major contributors. The first is the ozone-hole direct radiation effect (DRE) upon the surface that happens because the decrease of the downward longwave (LW) radiation overcomes the increase of the downward shortwave (SW) radiation under clear sky. The second is the cloud radiation effect (CRE) induced by ozone depletion, which happens because the decreased downward SW radiation overcomes the increased downward LW radiation in the case of increased cloud. Although the CRE is theoretically opposite to the DRE, their final net effect makes comparable contributions to the EA surface cooling. Compared with the surface radiation budget, the surface heat flux budgets have a much smaller contribution. We additionally note that the CRE is basically ascribed to the circulation change.

  15. Ozone

    SciTech Connect

    Not Available

    1988-06-01

    The author discusses the debate over whether concern about a hole in the ozone layer in Antarctic is real or science fiction. There is a growing consensus that efforts must be taken to protect the ozone layer. The issue now is not whether chlorofluorocarbons (CFCs) should be controlled and regulated but how much and how soon. The United States has urged that the production of dangerous CFCs, and any other chemicals that affect the ozone layer, be restricted immediately to current levels and that their use be reduced 95 percent over the next decade. The American position was too strong for many European nations and the Japanese. Negotiations at an international conference on the matter broke down. The breakdown is due in part to a more acute concern for environmental matters in the United States than exists in many countries. Meanwhile CFCs are linked to another environmental problem that equally threatens the world - the Greenhouse Effect. The earth is in a natural warming period, but man could be causing it to become even warmer. The Greenhouse Effect could have a catastrophic impact on mankind, although nothing has been proven yet.

  16. Questions and answers about the effects of the depletion of the ozone layer on humans and the environment.

    PubMed

    Aucamp, Pieter J

    2007-03-01

    The ozone molecule contains three atoms of oxygen and is mainly formed by the action of the ultraviolet rays of the sun on the diatomic oxygen molecules in the upper part of the Earth's atmosphere (called the stratosphere). Atmospheric pollution near the Earth's surface can form localized areas of ozone. The stratospheric ozone layer protects life on Earth by absorbing most of the harmful ultraviolet radiation from the sun. In the mid 1970s it was discovered that some manmade products destroy ozone molecules in the stratosphere. This destruction can result in damage to ecosystems and to materials such as plastics. It may cause an increase in human diseases such as skin cancers and cataracts. The discovery of the role of the synthetic ozone-depleting chemicals such as chlorofluorocarbons (CFCs) stimulated increased research and monitoring in this field. Computer models predicted a disaster if no action was taken to protect the ozone layer. Based on this research and monitoring, the nations of the world took action in 1985 with the Vienna Convention for the Protection of the Ozone Layer followed by the Montreal Protocol on Substances that Deplete the Ozone Layer in 1987. The Convention and Protocol were amended and adjusted several times as new knowledge was obtained. The Meetings of the Parties to the Montreal Protocol appointed three Assessment Panels to review the progress in scientific knowledge on their behalf. These panels are the Scientific Assessment Panel, the Technological and Economic Assessment Panel and the Environmental Effects Assessment Panel. Each panel covers a designated area and there is a natural level of overlap. The main reports of the Panels are published every four years as required by the Meeting of the Parties. All the reports have an executive summary that is distributed more widely than the main report itself. It became customary to add a set of questions and answers--mainly for non-expert readers--to the executive summaries. This

  17. A Two-Timescale Response of the Southern Ocean to Ozone Depletion: Importance of the Background State

    NASA Astrophysics Data System (ADS)

    Seviour, W.; Waugh, D.; Gnanadesikan, A.

    2016-02-01

    It has been recently suggested that the response of Southern Ocean sea-ice extent to stratospheric ozone depletion is time-dependent; that the ocean surface initially cools due to enhanced northward Ekman drift caused by a poleward shift in the eddy-driven jet, and then warms after some time due to upwelling of warm waters from below the mixed layer. It is therefore possible that ozone depletion could act to favor a short-term increase in sea-ice extent. However, many uncertainties remain in understanding this mechanism, with different models showing widely differing time-scales and magnitudes of the response. Here, we analyze an ensemble of coupled model simulations with a step-function ozone perturbation. The two-timescale response is present with an approximately 30 year initial cooling period. The response is further shown to be highly dependent upon the background ocean temperature and salinity stratification, which is influenced by both natural internal variability and the isopycnal eddy mixing parameterization. It is suggested that the majority of inter-model differences in the Southern Ocean response to ozone depletion are caused by differences in stratification.

  18. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing. (Invited)

    NASA Astrophysics Data System (ADS)

    Marshall, J.; Ferreira, D.; Bitz, C. M.

    2013-12-01

    In recent decades the Arctic has been warming with sea ice disappearing. But the Antarctic has been (mainly) cooling and sea ice is growing. We argue here that inter-hemispheric asymmetries in the mean ocean circulation, with sinking in the northern north Atlantic and upwelling around Antarctica, strongly influences the surface response to GHG forcing, accelerating warming in the Arctic and delaying it in the Antarctic. Moreover, while GHG forcing has been qualitatively similar at the poles, ozone depletion only occurs in the Antarctic. The coupled atmosphere-ocean response to ozone depletion may further help to explain the Antarctic trends. A framework is presented to quantify the processes at work built around `Climate Response Functions' for GHG and Ozone-hole forcing.

  19. A One-Dimensional Model Study of the Occurrence and the Termination of Polar Boundary-Layer Ozone Depletion Events

    NASA Astrophysics Data System (ADS)

    Cao, Le; Gutheil, Eva

    2015-04-01

    The tropospheric ozone depletion events (ODEs) in polar spring have attracted increased attention in the last thirty years. A dramatic decline of the surface ozone mixing ratio from tens of parts per billion (ppb) to less than one ppb within a few days is observed in various observation sites in polar regions. Previous studies suggest that the halogen species, especially bromine, acts as a catalyst in a chemical reaction cycle, which causes the destruction of ozone in the polar boundary layer. Moreover, a group of heterogeneous reactions with the involvement of HOBr occur on the surface of different substrates such as suspended aerosols and sea ice, leading to the activation of bromide from these substrates, and a following enhancement of the total bromine amount in the boundary layer occurs. This phenomenon is widely known as the 'bromine explosion' mechanism. However, the initiation and the termination steps of the ODEs are still not well understood. In the present study, a one-dimensional model, KINAL-T, is developed with the aim of investigating the role of the boundary layer in the occurrence and the termination of the ODEs. The 1-D model is an extension of the previous box model study1, explicitly including the vertical convection of gas. The parameterization of the vertical profile of the turbulent diffusivity from Pielke and Mahrer (1975)2 is adopted. Moreover, in the 1-D model, a bromine-related reaction scheme taken from Cao et al. (2014)1 is used, in which not only the gas phase but also the heterogeneous reactions are implemented. The simulation results show that the tropospheric ozone depletion event in a 200 m boundary layer starts after 12 days under the condition of a potential temperature gradient of 0.7 K km-1 and a wind speed of 5 m s-1. The whole depletion process of ozone takes approximately 2.5 days. The vertical profiles of ozone and bromine-containing compounds at different days are also captured. Instead of preventing the ozone from the

  20. The consequences for human health of stratospheric ozone depletion in association with other environmental factors.

    PubMed

    Lucas, R M; Norval, M; Neale, R E; Young, A R; de Gruijl, F R; Takizawa, Y; van der Leun, J C

    2015-01-01

    Due to the implementation of the Montreal Protocol, which has limited, and is now probably reversing, the depletion of the stratospheric ozone layer, only modest increases in solar UV-B radiation at the surface of the Earth have occurred. For many fair-skinned populations, changing behaviour with regard to exposure to the sun over the past half century - more time in the sun, less clothing cover (more skin exposed), and preference for a tan - has probably contributed more to greater levels of exposure to UV-B radiation than ozone depletion. Exposure to UV-B radiation has both adverse and beneficial effects on human health. This report focuses on an assessment of the evidence regarding these outcomes that has been published since our previous report in 2010. The skin and eyes are the organs exposed to solar UV radiation. Excessive solar irradiation causes skin cancer, including cutaneous malignant melanoma and the non-melanoma skin cancers, basal cell carcinoma and squamous cell carcinoma, and contributes to the development of other rare skin cancers such as Merkel cell carcinoma. Although the incidence of melanoma continues to increase in many countries, in some locations, primarily those with strong sun protection programmes, incidence has stabilised or decreased over the past 5 years, particularly in younger age-groups. However, the incidence of non-melanoma skin cancers is still increasing in most locations. Exposure of the skin to the sun also induces systemic immune suppression that may have adverse effects on health, such as through the reactivation of latent viral infections, but also beneficial effects through suppression of autoimmune reactivity. Solar UV-B radiation damages the eyes, causing cataracts and pterygium. UV-B irradiation of the skin is the main source of vitamin D in many geographic locations. Vitamin D plays a critical role in the maintenance of calcium homeostasis in the body; severe deficiency causes the bone diseases, rickets in children

  1. Atmosphere-derived National Emissions of Ozone Depleting Substances and Substitutes for the United States

    NASA Astrophysics Data System (ADS)

    Hu, L.; Montzka, S. A.; Miller, J. B.; Andrews, A. E.; Miller, B. R.; Lehman, S.; Godwin, D.; Thoning, K. W.; Sweeney, C.; Chen, H.; Fischer, M. L.; Biraud, S.; Torn, M. S.; Mountain, M. E.; Nehrkorn, T.; Eluszkiewicz, J.; Saikawa, E.; Hall, B. D.; Elkins, J. W.; Tans, P. P.

    2014-12-01

    Chlorofluorocarbons (CFCs), halons, carbon tetrachloride (CCl4), and methyl chloroform (CH3CCl3) are strong ozone-depleting substances (ODSs). Their production and consumption have been controlled by the Montreal Protocol since 1989 in developed countries and 1999 in developing countries. Although global atmospheric burdens of some of these gases have been declining for the last decade, their emissions continue due to releases from their existing reservoirs. Hydrochlorofluorocarbons (HCFCs) are transitional substitutes for CFCs; because they also deplete stratospheric ozone, they are also controlled by the Montreal Protocol. Hydrofluorocarbons (HFCs) are replacements for CFCs and HCFCs. Due to incomplete understanding of the reservoir size and emission rates for ODSs and their substitutes, uncertainty of their national emissions from inventory-based "bottom-up" estimates is undetermined. In this study, we use our atmospheric observations from multiple surface sites and aircraft profiles across the continental US from 2008 to 2012, along with data from remote sites over the Pacific basin, to derive national emissions of ODSs and their substitutes using inverse modeling. The performance of our modeling framework and the sensitivity of derived emissions to prior fluxes and model-data mismatch errors were investigated by conducting a suite of synthetic-data experiments. Sensitivity of derived fluxes to boundary values and transport was explored in real-data inversions. Our preliminary results suggest that (1) US emissions of HCFC-22 and HCFC-142b are currently declining at faster rates than those reported by US EPA; (2) our emission estimate of HFC-134a, the most abundant HFCs in the atmosphere, is consistent with the estimate reported by US EPA, whereas our estimates for some currently minor HFCs (i.e. HFC-125 and HFC-143a) show no significant emission trends during 2008 - 2012, which is inconsistent with a 70 - 120 % increase over this period reported by US EPA; and

  2. Nocturnal Ozone Depletion Events at the Amphitrite Point Observatory on West Vancouver Island

    NASA Astrophysics Data System (ADS)

    Garner, N.; Brownsey, D. K.; Tokarek, T. W.; Ye, C. Z.; Yordanov, N. R.; Osthoff, H. D.; Schiller, C. L.; Vingarzan, R.

    2015-12-01

    Routine monitoring stations on the West coast of North America serve to monitor baseline levels of criteria pollutants such as ozone (O3) arriving from the Pacific Ocean. In Canada, the Amphitrite Point Observatory (APO) in Ucluelet on the West coast of Vancouver Island has been added to this network to provide regional baseline measurements. Recently, McKendry and coworkers have reported frequent episodes of nocturnal O3 depletion events (ODEs) at APO (range: 5-20 ppbv) that generally correlate with alongshore winds, elevated levels of carbon dioxide (CO2), and low vertical entrainment but whose cause(s) has (have) remained unclear. In this work, results from the Ozone-depleting reactions in a coastal atmosphere (ORCA) campaign, which took place at APO from July 6 - 31, 2015, are presented. In addition to the long-term measurements that include aerosol size distribution and composition measurements, mixing ratios of speciated monoterpenes (e.g., α- and β-pinene, limonene), molecular halogens (i.e., Cl2, I2), halogen oxides (i.e., OIO), plus a full suite of nitrogen oxides (including N2O5, PAN, PPN, ΣPN, ΣAN, HNO3, HONO, and ClNO2) were quantified. Synoptic conditions at the site varied greatly between nights. During westerly flow of relatively clean marine air, O3 was generally conserved at night, indicating that deposition of O3 to the ocean surface is a minor loss pathway. When the air mass originated from other sectors, episodes of nocturnal ODEs were observed on several occasions, in which mixing ratios of biogenic VOCs were enhanced. These included air masses that originated from densely forested areas to the East, air masses polluted by marine traffic emissions from the southeast, and air masses from the NW that have traveled parallel to the coastline. In this sector, the air was likely in contact with terrestrial vegetation via land-sea breeze circulations. The results suggest that nocturnal ODEs at APO are mainly driven by local or regional processes

  3. Climate Throughout Geologic Time Was Cooled by Sequences of Explosive Volcanic Eruptions Forming Aerosols That Reflect and Scatter Ultraviolet Solar Radiation and Warmed by Relatively Continuous Extrusion of Basaltic Lava that Depletes Ozone, Allowing More Solar Ultraviolet Radiation to Reach Earth

    NASA Astrophysics Data System (ADS)

    Ward, P. L.

    2015-12-01

    Active volcanoes of all sizes and eruptive styles, emit chlorine and bromine gases observed to deplete ozone. Effusive, basaltic volcanic eruptions, typical in Hawaii and Iceland, extrude large lava flows, depleting ozone and causing global warming. Major explosive volcanoes also deplete ozone with the same emissions, causing winter warming, but in addition eject megatons of water and sulfur dioxide into the lower stratosphere where they form sulfuric-acid aerosols whose particles grow large enough to reflect and scatter ultraviolet sunlight, causing net global cooling for a few years. The relative amounts of explosive and effusive volcanism are determined by the configuration of tectonic plates moving around Earth's surface. Detailed studies of climate change throughout geologic history, and since 1965, are not well explained by greenhouse-gas theory, but are explained quite clearly at OzoneDepletionTheory.info. Ozone concentrations vary substantially by the minute and show close relationships to weather system highs and lows (as pointed out by Dobson in the 1920s), to the height of the tropopause, and to the strength and location of polar vortices and jet streams. Integrating the effects of volcanism on ozone concentrations and the effects of ozone concentrations on synoptic weather patterns should improve weather forecasting. For example, the volcano Bárðarbunga, in central Iceland, extruded 85 km2 of basaltic lava between August 29, 2014, and February 28, 2015, having a profound effect on weather. Most surprising, more than a week before the March 4 eruption of Eyjafjallajökull in 2010, substantial amounts of ozone were released in the vicinity of the volcano precisely when surface deformation showed that magma first began moving up from sills below 4 km depth. Ozone similarly appears to have been emitted 3.5 months before the Pinatubo eruption in 1991. Readily available daily maps of ozone concentrations may allow early warning of an imminent volcanic

  4. Transmission of ultraviolet radiation in Antarctic coastal waters during springtime ozone depletion

    SciTech Connect

    Karentz, D. )

    1990-01-09

    Annual springtime ozone depletion over Antarctica has resulted in increased intensities of biologically harmful ultraviolet-B (UV-B) radiation reaching the earth's surface. This phenomenon has prompted much concern and speculation abouth the impact of elevated UV-B irradiance on Antarctic marine ecosystems, but there are limited data available to evaluate specific effects. A major obstacle is lack of information on UV-B exposure experienced by organisms within the marine environment. During the spring (Oct-Dec) of 1988, radiometry (instantaneous measurement of broad band UV-A and UV-B), actinometry (UV-B flux) and newly developed biological dosimetry biologically transmission of UV radiation within the water column (0-30 m) of Arthur Harbor (Anvers Island, Antarctic Peninsula). The dosimeter system consistently detected biologically active wavelengths of UV-B to 10 m throughout the study period and to 20 m on some sample dates, indicating that intertidal, shallow benthic and planktonic communities are exposed to biologically hazardous UV radiation.

  5. CFC users seek exemptions from ban on ozone-depleting substances

    SciTech Connect

    Zurer, P.

    1993-08-16

    Environmental Protection Agency officials were surprised last month as the deadline passed for chlorofluorocarbon (CFC) users to ask for exemptions from the production ban that goes into effect in less than 29 months. Only a handful of CFC users petitioned EPA to put their case before the countries that are party to the Montreal Protocol on Substances That Deplete the Ozone Layer. Three major groups--as well as a few other minor users--say they must have CFCs available after the Jan. 1, 1996, phaseout deadline. The automobile industry and commercial building owners cite the turmoil and expense of switching to substitutes for existing air-conditioning and commercial building owners cite the turmoil and expense of switching to substitutes for existing air-conditioning equipment. And the pharmaceutical industry has not yet developed approved alternatives for certain medical devices. But only metered-dose inhalers, which use CFCs to propel medication directly into the lungs of patients suffering from asthma and other respiratory diseases, are likely to be deemed an exempt essential use.

  6. From ozone depletion to agriculture: understanding the role of UV radiation in sustainable crop production.

    PubMed

    Wargent, Jason J; Jordan, Brian R

    2013-03-01

    Largely because of concerns regarding global climate change, there is a burgeoning interest in the application of fundamental scientific knowledge in order to better exploit environmental cues in the achievement of desirable endpoints in crop production. Ultraviolet (UV) radiation is an energetic driver of a diverse range of plant responses and, despite historical concerns regarding the damaging consequences of UV-B radiation for global plant productivity as related to stratospheric ozone depletion, current developments representative of a range of organizational scales suggest that key plant responses to UV-B radiation may be exploitable in the context of a sustainable contribution towards the strengthening of global crop production, including alterations in secondary metabolism, enhanced photoprotection, up-regulation of the antioxidative response and modified resistance to pest and disease attack. Here, we discuss the prospect of this paradigm shift in photobiology, and consider the linkages between fundamental plant biology and crop-level outcomes that can be applied to the plant UV-B response, in addition to the consequences for related biota and many other facets of agro-ecosystem processes. © 2013 The Author. New Phytologist © 2012 New Phytologist Trust.

  7. Interactive effects of ozone depletion and climate change on biogeochemical cycles.

    PubMed

    Zepp, Richard G; Callaghan, Terry V; Erickson, David J

    2003-01-01

    The effects of ozone depiction on global biogeochemical cycles, via increased UV-B radiation at the Earth's surface, have continued to be documented over the past 4 years. In this report we also document various effects of UV-B that interact with global climate change because the detailed interactions between ozone depletion and climate change are central to the prediction and evaluation of future Earth environmental conditions. There is increasing evidence that elevated UV-B has significant effects on the terrestrial biosphere with important implications for the cycling of carbon, nitrogen and other elements. Increased UV has been shown to induce carbon monoxide production from dead plant matter in terrestrial ecosystems, nitrogen oxide production from Arctic and Antarctic snowpacks, and halogenated substances from several terrestrial ecosystems. New studies on UV effects on the decomposition of dead leaf material confirm that these effects are complex and species-specific. Decomposition can be retarded, accelerated or remain unchanged. It has been difficult to relate effects of UV on decomposition rates to leaf litter chemistry, as this is very variable. However, new evidence shows UV effects on some fungi, bacterial communities and soil fauna that could play roles in decomposition and nutrient cycling. An important new result is that not only is nitrogen cycling in soils perturbed significantly by increased UV-B, but that these effects persist for over a decade. As nitrogen cycling is temperature dependent, this finding clearly links the impacts of ozone depletion to the ability of plants to use nitrogen in a warming global environment. There are many other potential interactions between UV and climate change impacts on terrestrial biogeochemical cycles that remain to be quantified. There is also new evidence that UV-B strongly influences aquatic carbon, nitrogen, sulfur, and metals cycling that affect a wide range of life processes. UV-B accelerates the

  8. Evaluation of a no-clean soldering process designed to eliminate the use of ozone depleting chemicals

    SciTech Connect

    Iman, R.L.; Armendariz, M.E.; Anderson, D.J. |; Lichtenberg, L.; Van Buren, P.; Paffett, M.T.

    1992-11-01

    The destruction of the Earth`s protective ozone layer is one of today`s largest environmental concerns. Solvent emissions released during the cleaning of printed wiring boards (PWBs) have been identified as a primary contributor to ozone destruction. No-clean soldering (sometimes referred to as self-cleaning) processes represent an ideal solution since they eliminate the need for cleaning after soldering. Elimination of solvent cleaning operations significantly reduces the emissions of ozone depleting chemicals (ODCs), reduces energy consumption, and reduces product costs. Several no-clean soldering processes have been developed over the past few years. The program`s purpose was to evaluate the no-clean soldering process and to determine if hardware produced by the process is acceptable for military applications. That is, determine if the no-clean process produces hardware that is as reliable as that soldered with the existing rosin-based flux solvent cleaning process.

  9. Semi-empirical models for chlorine activation and ozone depletion in the Antarctic stratosphere: proof of concept

    NASA Astrophysics Data System (ADS)

    Huck, P. E.; Bodeker, G. E.; Kremser, S.; McDonald, A. J.; Rex, M.; Struthers, H.

    2013-03-01

    Two semi-empirical models were developed for the Antarctic stratosphere to relate the shift of species within total chlorine (Cly = HCl + ClONO2 + HOCl + 2 × Cl2 + 2×Cl2O2 + ClO + Cl) into the active forms (here: ClOx = 2×Cl2O2 + ClO), and to relate the rate of ozone destruction to ClOx. These two models provide a fast and computationally inexpensive way to describe the inter- and intra-annual evolution of ClOx and ozone mass deficit (OMD) in the Antarctic spring. The models are based on the underlying physics/chemistry of the system and capture the key chemical and physical processes in the Antarctic stratosphere that determine the interaction between climate change and Antarctic ozone depletion. They were developed considering bulk effects of chemical mechanisms for the duration of the Antarctic vortex period and quantities averaged over the vortex area. The model equations were regressed against observations of daytime ClO and OMD providing a set of empirical fit coefficients. Both semi-empirical models are able to explain much of the intra- and inter-annual variability observed in daily ClOx and OMD time series. This proof-of-concept paper outlines the semi-empirical approach to describing the evolution of Antarctic chlorine activation and ozone depletion.

  10. Ultraviolet radiation affects emission of ozone-depleting substances by marine macroalgae: results from a laboratory incubation study.

    PubMed

    Laturnus, Frank; Svensson, Teresia; Wiencke, Christian; Oberg, Gunilla

    2004-12-15

    The depletion of stratospheric ozone due to the effects of ozone-depleting substances, such as volatile organohalogens, emitted into the atmosphere from industrial and natural sources has increased the amount of ultraviolet radiation reaching the earth's surface. Especially in the subpolar and polar regions, where stratospheric ozone destruction is the highest, individual organisms and whole ecosystems can be affected. In a laboratory study, several species of marine macroalgae occurring in the polar and northern temperate regions were exposed to elevated levels of ultraviolet radiation. Most of the macroalgae released significantly more chloroform, bromoform, dibromomethane, and methyl iodide-all volatile organohalogens. Calculating on the basis of the release of total chlorine, bromine, and iodine revealed that, except for two macroalgae emitting chlorine and one alga emitting iodine, exposure to ultraviolet radiation caused macroalgae to emit significantly more total chlorine, bromine, and iodine. Increasing levels of ultraviolet radiation due to possible further destruction of the stratospheric ozone layer as a result of ongoing global atmospheric warming may thus increase the future importance of marine macroalgae as a source for the global occurrence of reactive halogen-containing compounds.

  11. A general circulation model study of the climatic effect of observed stratospheric ozone depletion between 1980 and 1990

    NASA Technical Reports Server (NTRS)

    Dudek, Michael P.; Wang, Wei-Chyung; Liang, Xin-Zhong; Li, Zhu

    1994-01-01

    The total ozone mapping spectrometer (TOMS) and stratospheric aerosol and gas experiment (SAGE) measurements show a significant reduction in the stratospheric ozone over the middle and high latitudes of both hemispheres between the years 1979 and 1991 (WMO, 1992). This change in ozone will effect both the solar and longwave radiation with climate implications. However, recent studies (Ramaswamy et al., 1992; WMO, 1992) indicate that the net effect depends not only on latitudes and seasons, but also on the response of the lower stratospheric temperature. In this study we use a general circulation model (GCM) to calculate the climatic effect due to stratospheric ozone depletion and compare the effect with that due to observed increases of trace gases CO2, CH4, N2O, and CFC's for the period 1980-1990. In the simulations, we use the observed changes in ozone derived from the TOMS data. The GCM used is a version of the NCAR community climate model referenced in Wang et al. (1991). For the present study we run the model in perpetual January and perpetual July modes in which the incoming solar radiation and climatological sea surface temperatures are held constant.

  12. The effects on human health from stratospheric ozone depletion and its interactions with climate change.

    PubMed

    Norval, M; Cullen, A P; de Gruijl, F R; Longstreth, J; Takizawa, Y; Lucas, R M; Noonan, F P; van der Leun, J C

    2007-03-01

    Ozone depletion leads to an increase in the ultraviolet-B (UV-B) component (280-315 nm) of solar ultraviolet radiation (UVR) reaching the surface of the Earth with important consequences for human health. Solar UVR has many harmful and some beneficial effects on individuals and, in this review, information mainly published since the previous report in 2003 (F. R. de Gruijl, J. Longstreth, M. Norval, A. P. Cullen, H. Slaper, M. L. Kripke, Y. Takizawa and J. C. van der Leun, Photochem. Photobiol. Sci., 2003, 2, pp. 16-28) is discussed. The eye is exposed directly to sunlight and this can result in acute or long-term damage. Studying how UV-B interacts with the surface and internal structures of the eye has led to a further understanding of the location and pathogenesis of a number of ocular diseases, including pterygium and cataract. The skin is also exposed directly to solar UVR, and the development of skin cancer is the main adverse health outcome of excessive UVR exposure. Skin cancer is the most common form of malignancy amongst fair-skinned people, and its incidence has increased markedly in recent decades. Projections consistently indicate a further doubling in the next ten years. It is recognised that genetic factors in addition to those controlling pigment variation can modulate the response of an individual to UVR. Several of the genetic factors affecting susceptibility to the development of squamous cell carcinoma, basal cell carcinoma and melanoma have been identified. Exposure to solar UVR down-regulates immune responses, in the skin and systemically, by a combination of mechanisms including the generation of particularly potent subsets of T regulatory cells. Such immunosuppression is known to be a crucial factor in the generation of skin cancers. Apart from a detrimental effect on infections caused by some members of the herpesvirus and papillomavirus families, the impact of UV-induced immunosuppression on other microbial diseases and vaccination

  13. Prospective Primary Teachers' Understanding of Climate Change, Greenhouse Effect, and Ozone Layer Depletion

    ERIC Educational Resources Information Center

    Papadimitriou, Vasiliki

    2004-01-01

    Climate change is one of the most serious global environmental problems and for that reason there has been lately a great interest in educating pupils, the future citizens, about it. Previous research has shown that pupils of all ages and teachers hold many misconceptions and misunderstandings concerning this issue. This paper reports on research…

  14. Prospective Primary Teachers' Understanding of Climate Change, Greenhouse Effect, and Ozone Layer Depletion

    ERIC Educational Resources Information Center

    Papadimitriou, Vasiliki

    2004-01-01

    Climate change is one of the most serious global environmental problems and for that reason there has been lately a great interest in educating pupils, the future citizens, about it. Previous research has shown that pupils of all ages and teachers hold many misconceptions and misunderstandings concerning this issue. This paper reports on research…

  15. Quantifying urban/industrial emissions of greenhouse and ozone-depleting gases based on atmospheric observations

    NASA Astrophysics Data System (ADS)

    Barnes, Diana Hart

    2000-11-01

    Background and pollution trends and cycles of fourteen trace gases over the Northeastern U.S. are inferred from continuous atmospheric observations at the Harvard Forest research station located in Petersham, Massachusetts. This site receives background `clean' air from the northwest (Canada) and `dirty' polluted air from the southwest (New York City-Washington, D.C. corridor). Mixing ratios of gases regulated by the Montreal Protocol or other policies (CO, PCE, CFC11, CFC12, CFC113, CH 3CCl3, CCl4, and Halon-1211) and of those not subject to restrictions (H2, CH4, CHCl3, TCE, N2O, and SF6) were measured over the three-year period, 1996 to 1998, every 24 minutes by a fully automated gas chromatographic instrument with electron capture detectors. Evidence for polar vortex venting is found consistently in the month of June of the background seasonal cycles. The ratio of CO and PCE enhancements borne on southwesterly winds are in excellent agreement with county-level EPA and sales-based inventories for the New York City-Washington, D.C. region. From this firm footing, we use CO and PCE as reference compounds to determine the urban/industrial source strengths for the other species. A broad historical and geographic study of emissions reveals that the international treaty has by and large been a success. Locally, despite the passing of the 1996 Montreal Protocol ban, only emissions of CFC12 and CH3CCl3 are abating. Though source strengths are waning, the sources are not spent and continued releases to the atmosphere may be expected for some years to come. For CH3CCl3, whose rate of decline is central to our understanding of atmospheric processes, we estimate that absolute concentrations may persist until around the year 2010. The long-term high frequency time series of hydrogen provided here represents the first such data set of its kind. The H2 diurnal cycle is established and explained in terms of its sources and sinks. The ratio of H2 to CO in pollution plumes is found to be a seasonal and unchanged since early automobile exhaust studies of the 1960s, despite the many restrictions placed on car emissions and fuels since that time. Based on this result, a spatial inventory of H2 emissions from fossil fuel combustion is developed at the county level for the entire Northeastern U.S.

  16. Have we underestimated the role of short-lived chlorine compounds in ozone depletion?

    NASA Astrophysics Data System (ADS)

    Oram, David; Laube, Johannes; Sturges, Bill; Gooch, Lauren; Leedham, Emma; Ashfold, Matthew; Pyle, John; Abu Samah, Azizan; Moi Phang, Siew; Ou-Yang, Chang-Feng; Lin, Neng-Huei; Wang, Jia-Lin; Brenninkmeijer, Carl

    2015-04-01

    In recent years much attention has been focussed on the potential of bromine-containing VSLS (very short lived substances) to contribute to stratospheric ozone depletion. This is primarily due to the large observed discrepancy between the measured inorganic bromine in the stratosphere and the amount of bromine available from known, longer lived sources gases (halons and CH3Br). In contrast, the role of very short-lived chlorine compounds (VSLS-CL) has been considered trivial because they contribute only a few percent to the total organic chlorine in the troposphere, the majority of which is supplied by long-lived compounds such as the CFCs, HCFCs, methyl chloroform and carbon tetrachloride. However recent evidence shows that one VSLS-Cl, dichloromethane (CH2Cl2) has increased by 60% over the past decade (WMO, 2014) and has already begun to offset the long-term decline in stratospheric chlorine loading caused by the reduction in emissions of substances controlled by the Montreal Protocol. We will present new VSLS-Cl measurements from recent ground-based and aircraft campaigns in SE Asia where we have observed dramatic enhancements in a number of VSLS-Cl, including CH2Cl2. Furthermore we will demonstrate how pollution from China and the surrounding region can rapidly, and regularly, be transported across the South China Sea and subsequently uplifted to altitudes of 11-12 km, the region close to the lower TTL. This process occurs frequently during the winter monsoon season and could represent a fast and efficient mechanism for transporting short-lived compounds, and other pollutants, to the lower stratosphere.

  17. Emission location dependent ozone depletion potentials for very short-lived halogenated species

    NASA Astrophysics Data System (ADS)

    Pisso, I.; Haynes, P. H.; Law, K. S.

    2010-12-01

    We present trajectory-based estimates of Ozone Depletion Potentials (ODPs) for very short-lived halogenated source gases as a function of surface emission location. The ODPs are determined by the fraction of source gas and its degradation products which reach the stratosphere, depending primarily on tropospheric transport and chemistry, and the effect of the resulting reactive halogen in the stratosphere, which is determined by stratospheric transport and chemistry, in particular by stratospheric residence time. Reflecting the different timescales and physico-chemical processes in the troposphere and stratosphere, the estimates are based on calculation of separate ensembles of trajectories for the troposphere and stratosphere. A methodology is described by which information from the two ensembles can be combined to give the ODPs. The ODP estimates for a species with a fixed 20 d lifetime, representing a compound like n-propyl bromide, are presented as an example. The estimated ODPs show strong geographical and seasonal variation, particularly within the tropics. The values of the ODPs are sensitive to the inclusion of a convective parametrization in the trajectory calculations, but the relative spatial and seasonal variation is not. The results imply that ODPs are largest for emissions from south and south-east Asia during Northern Hemisphere summer and from the western Pacific during Northern Hemisphere winter. Large ODPs are also estimated for emissions throughout the tropics with non-negligible values also extending into northern mid-latitudes, particularly in the summer. These first estimates, whilst made under some simplifying assumptions, show larger ODPs for certain emission regions, particularly south Asia in NH summer, than have typically been reported by previous studies which used emissions distributed evenly over land surfaces.

  18. Ozone depletion in the high latitude lower stratosphere - 1979-1990

    NASA Technical Reports Server (NTRS)

    Callis, Linwood B.; Boughner, Robert E.; Natarajan, Murali; Lambeth, James D.; Baker, Daniel N.

    1991-01-01

    Archived Stratospheric Aerosol and Gas Experiment (SAGE, SAGE II) and Solar and Backscattered Ultraviolet (SBUV) data are used to examine lower stratospheric O3 variations at 50 deg latitude in both hemispheres. These data indicate that from 1979 to 1985, 73-90 percent of the total O3 changes have occurred below approximately 25 km in altitude. Significant O3 depletions (up to 15 percent) have occurred in the partial column (127-15.8 mbar) in both hemispheres with indications of a recovery after 1985. Two-dimensional model simulations of O3 changes from 1979 to 1990 have been carried out. Comparisons with O3 data are presented. Model results suggest that by 1985, significant declines in global O3 were caused by destruction by odd nitrogen associated with long-term variations in the flux of precipitating relativistic electrons (2.6 percent); solar UV flux changes (1.8 percent); the dilution effect associated with the Antarctic O3 hole (1.2 percent); and atmospheric increases in CH4, N2O, and chlorofluorocarbons (0.4 percent). Analyses of drift-corrected SBUV and Total Ozone Mapping Spectrometer data and model calculations indicate that between 1979 and 1985, reductions of 4.3 to 4.8 percent in total column O3 averaged between 65 deg S and 65 deg N have occurred. Calculations indicate a full global O3 decline of 5.2 percent (peak-to-peak) or 6 percent (annual average) between 1979 and 1985 with a partial recovery between 1985 and 1989.

  19. Growth of soybean at future tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion.

    PubMed

    Bernacchi, Carl J; Leakey, Andrew D B; Kimball, Bruce A; Ort, Donald R

    2011-06-01

    Tropospheric ozone is increasing in many agricultural regions resulting in decreased stomatal conductance and overall biomass of sensitive crop species. These physiological effects of ozone forecast changes in evapotranspiration and thus in the terrestrial hydrological cycle, particularly in intercontinental interiors. Soybean plots were fumigated with ozone to achieve concentrations above ambient levels over five growing seasons in open-air field conditions. Mean season increases in ozone concentrations ([O₃]) varied between growing seasons from 22 to 37% above background concentrations. The objective of this experiment was to examine the effects of future [O₃] on crop ecosystem energy fluxes and water use. Elevated [O₃] caused decreases in canopy evapotranspiration resulting in decreased water use by as much as 15% in high ozone years and decreased soil water removal. In addition, ozone treatment resulted in increased sensible heat flux in all years indicative of day-time increase in canopy temperature of up to 0.7 °C. Published by Elsevier Ltd.

  20. Relationship of inhaled ozone concentration to acute tracheobronchial epithelial injury, site-specific ozone dose, and glutathione depletion in rhesus monkeys.

    PubMed

    Plopper, C G; Hatch, G E; Wong, V; Duan, X; Weir, A J; Tarkington, B K; Devlin, R B; Becker, S; Buckpitt, A R

    1998-09-01

    Acute pulmonary epithelial injury produced by short-term exposure to ozone varies by site within the tracheobronchial tree. To test whether this variability is related to the local dose of ozone at the tissue site or to local concentrations of glutathione, we exposed adult male rhesus monkeys for 2 h to filtered air or to 0.4 or 1.0 ppm ozone generated from 18O2. Following exposure, lungs were split into lobes and specimens were selected by microdissection so that measurements could be made on airway tissue of similar branching history, including trachea, proximal (generation one or two) and distal (generation six or seven) intrapulmonary bronchi, and proximal respiratory bronchioles. One half of the lung was lavaged for analysis of extracellular components. In monkeys exposed to filtered air, the concentration of reduced glutathione (GSH) varied throughout the airway tree, with the proximal intrapulmonary bronchus having the lowest concentration and the parenchyma having the highest concentration. Exposure to 1.0 ppm ozone significantly reduced GSH only in the respiratory bronchiole, whereas exposure to 0.4 ppm increased GSH only in the proximal intrapulmonary bronchus. Local ozone dose (measured as excess 18O) varied by as much as a factor of three in different airways of monkeys exposed to 1.0 ppm, with respiratory bronchioles having the highest concentration and the parenchyma the lowest concentration. In monkeys exposed to 0.4 ppm, the ozone dose was 60% to 70% less than in the same site in monkeys exposed to 1.0 ppm. Epithelial disruption was present to some degree in all airway sites, but not in the parenchyma, in animals exposed to 1.0 ppm ozone. The mass of mucous and ciliated cells decreased in all airways, and necrotic and inflammatory cells increased. At 0.4 ppm, epithelial injury was minimal, except in the respiratory bronchiole, where cell loss and necrosis occurred, and was 50% that found in monkeys exposed to 1.0 ppm ozone. We conclude that there is

  1. Sensitivity of global greenhouse gas budgets to tropospheric ozone pollution mediated by the biosphere

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Shugart, Herman H.; Lerdau, Manuel T.

    2017-08-01

    Tropospheric ozone (O3), a harmful secondary air pollutant, can affect the climate via direct radiative forcing and by modifying the radiative forcing of aerosols through its role as an atmospheric oxidant. Moreover, O3 exerts a strong oxidative pressure on the biosphere and indirectly influences the climate by altering the materials and energy exchange between terrestrial ecosystems and the atmosphere. However, the magnitude by which O3 affects the global budgets of greenhouse gases (GHGs: CO2, CH4, and N2O) through altering the land-atmosphere exchange is largely unknown. Here we assess the sensitivity of these budgets to tropospheric O3 pollution based on a meta-analysis of experimental studies on the effects of elevated O3 on GHG exchange between terrestrial ecosystems and the atmosphere. We show that across ecosystems, elevated O3 suppresses N2O emissions and both CH4 emissions and uptake, and has little impact on stimulation of soil CO2 emissions except at relatively high concentrations. Therefore, the soil system would be transformed from a sink into a source of GHGs with O3 levels increasing. The global atmospheric budget of GHGs is sensitive to O3 pollution largely because of the carbon dioxide accumulation resulting from suppressed vegetation carbon uptake; the negative contributions from suppressed CH4 and N2O emissions can offset only ˜10% of CO2 emissions from the soil-vegetation system. Based on empirical data, this work, though with uncertainties, provides the first assessment of sensitivity of global budgets of GHGs to O3 pollution, representing a necessary step towards fully understanding and evaluating O3-climate feedbacks mediated by the biosphere.

  2. Growth of soybean at midcentury tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion

    USDA-ARS?s Scientific Manuscript database

    Ground-level concentrations of ozone are increasing as a result of anthropogenic activities. This is having a negative impact on terrestrial ecosystems around the planet, including agricultural ecosystems. Critical questions surround the impact of rising ozone on soybean (Glycine max) since this spe...

  3. Occurrence of near-surface ozone depletion in the Arctic spring strongly affected by Northern-Hemispheric climate variability

    NASA Astrophysics Data System (ADS)

    Koo, J.; Wang, Y.; Jiang, T.; Deng, Y.; Oltmans, S. J.; Solberg, S.

    2013-12-01

    In the Arctic spring, near-surface ozone can decrease to extremely low levels due to chemical removal catalyzed by halogen radicals. These ozone depletion events (ODEs) are usually accompanied by greatly enhanced surface deposition of reactive gaseous mercury. Here we show the effects of regional climate variability on Arctic ODE frequencies by analyzing surface ozone measurements at three monitoring sites (Barrow, Alert, and Zeppelinfjellet) in the past 30 years. Among the various climate variability indices, the Western Pacific (WP) index has the most significant impact. In years with high ODE frequencies at Barrow and Alert in April, the WP teleconnection pattern tends to be in its negative phase with a weakened storm track from the western Pacific to the Arctic and a strengthened subtropical jet across the Pacific, reducing transport of ozone-rich air masses from mid-latitudes to the Arctic. Analysis of the observations at Zeppelinfjellet indicates a much stronger influence of WP pattern in the 2000s than 1990s. Consequently, the WP index may be used as a proxy to assess ODE frequencies and subsequent environmental impacts in future climate projections.

  4. Heterogeneous chemistry related to Antarctic ozone depletion: Reaction of ClONO2 and N2O5 on ice surfaces

    NASA Technical Reports Server (NTRS)

    Tolbert, Margaret A.; Rossi, Michel J.; Golden, David M.

    1988-01-01

    Laboratory studies of heterogeneous reactions of possible importance for Antarctic ozone depletion were performed. In particular, the reactions of chlorine nitrate (ClONO2) and dinitrogen pentoxide (N2O5) were investigated on ice and HCl/ice surfaces. These reactions occur on the surfaces of polar stratospheric clouds (PSCs) over Antarctica. One reaction transforms the stable chlorine reservoir species (ClONO2 and HCl) into photochemically active chlorine in the form of HOCl and Cl2. Condensation of HNO3 in the reactions removes odd nitrogen from the stratosphere, a requirement in nearly all models of Antarctic ozone depletion. Other reactions may also be important for Antarctic ozone depletion. Like the reactions of chlorine nitrate, these reactions deplete odd nitrogen through HNO3 condensation. In addition, one reaction converts a stable chlorine reservior species (HCl) into photochemically active chlorine (ClNO2). These reactions were studied with a modified version of a Knudsen cell flow reactor.

  5. Volcanoes drive climate variability by emitting ozone weeks before eruptions, by forming lower stratospheric aerosols, by causing sustained ozone depletion, and by causing rapid changes in regional ozone concentrations affecting temperature and pressure differences driving atmospheric oscillations

    NASA Astrophysics Data System (ADS)

    Ward, P. L.

    2016-12-01

    Total column ozone observed by satellite on February 19, 2010, increased 75% in a plume from Eyjafjallajökull volcano in southern Iceland eastward past Novaya Zemlya, extending laterally from northern Greenland to southern Norway (http://youtu.be/wJFZcPEfoR4). Contemporaneous ground deformation and rapidly increasing numbers of earthquakes imply magma began rising from a sill 4-6 km below the volcano, erupting a month later. Whether the ozone formed from the magma or from very hot gases rising through cracks in the ground is unclear. On February 20-22, 1991, similar increases in ozone were observed north of Pinatubo volcano before its initial eruption on April 2 (http://youtu.be/5y1PU2Qu3ag). Annual average total column ozone during the year of most moderate to large explosive volcanic eruptions since routine observations of ozone began in 1927 has been substantially higher than normal. Increased total column ozone absorbs more solar ultraviolet-B radiation, warming the ozone layer and cooling Earth. Most major volcanic eruptions form sulfuric-acid aerosols in the lower part of the ozone layer providing aqueous surfaces on which heterogeneous chemical reactions enhance ozone depletion. Within a year, aerosol droplets grew large enough to reflect and scatter high-frequency solar radiation, cooling Earth 0.5oC for 2-3 years. Temperature anomalies in the northern hemisphere rose 0.7oC in 28 years from 1970 to 1998 (HadCRUT4), while annual average ozone at Arosa dropped 27 DU because of manufactured CFC gases. Beginning in August 2014, temperature anomalies in the northern hemisphere rose another 0.6oC in less than two years apparently because of the 6-month eruption of Bárðarbunga volcano in central Iceland, the highest rate of basaltic lava extrusion since 1783. Large extrusions of basaltic lava are typically contemporaneous with the greatest periods of warming throughout Earth history. Ozone concentrations at Arosa change by season typically from 370 DU during

  6. Influence of polar stratospheric clouds on the depletion of Antarctic ozone

    NASA Technical Reports Server (NTRS)

    Salawitch, Ross J.; Wofsy, Steven C.; Mcelroy, Michael B.

    1988-01-01

    Precipitation of nitrate in polar stratospheric clouds (PSCs) can provide a significant sink for Antarctic stratospheric odd nitrogen. It is argued that the depth of the Ozone Hole is sensitive to the occurrence of temperatures below about 196 K. An increase in the prevalence of temperatures below 196 K would enhance ozone loss by increasing the spatial extent and persistence of PSCs, and by decreasing the level of HNO3 that remains following PSC evaporation. Concentrations of halogen gases in the 1960s and earlier were insufficient to support major ozone loss, even if thermal conditions were favorable.

  7. Next Generation Refrigeration Lubricants for Low Global Warming Potential/Low Ozone Depleting Refrigeration and Air Conditioning Systems

    SciTech Connect

    Hessell, Edward Thomas

    2013-12-31

    The goal of this project is to develop and test new synthetic lubricants that possess high compatibility with new low ozone depleting (LOD) and low global warming potential (LGWP) refrigerants and offer improved lubricity and wear protection over current lubricant technologies. The improved compatibility of the lubricants with the refrigerants, along with improved lubricating properties, will resulted in lower energy consumption and longer service life of the refrigeration systems used in residential, commercial and industrial heating, ventilating and air-conditioning (HVAC) and refrigeration equipment.

  8. Operation Aurorozone: An experiment in sun/weather. [effects of aurorall produced X-rays on ozone depletion

    NASA Technical Reports Server (NTRS)

    Goldberg, R. A.; Hilsenrath, E.

    1977-01-01

    Operation Aurorozone was a highly coordinated sequence of 33 rocket flights launched from Poker Flat, Alaska, in September 1976. The effects of aurorally produced X-rays on stratospheric neutral and electrical parameters was studied. The sun/weather coupling between upper and lower regions of the atmosphere is thought to be related to these middle atmospheric parameters. The results show a consistent depletion of ozone above 1 mb during three independent auroral events, with magnitudes in excess of those expected from the measured energy radiation sources. Simultaneously, enhanced conductivity changes were observed to occur in accord with the measured ionizing radiations.

  9. Operation Aurorozone: An experiment in sun/weather. [effects of aurorall produced X-rays on ozone depletion

    NASA Technical Reports Server (NTRS)

    Goldberg, R. A.; Hilsenrath, E.

    1977-01-01

    Operation Aurorozone was a highly coordinated sequence of 33 rocket flights launched from Poker Flat, Alaska, in September 1976. The effects of aurorally produced X-rays on stratospheric neutral and electrical parameters was studied. The sun/weather coupling between upper and lower regions of the atmosphere is thought to be related to these middle atmospheric parameters. The results show a consistent depletion of ozone above 1 mb during three independent auroral events, with magnitudes in excess of those expected from the measured energy radiation sources. Simultaneously, enhanced conductivity changes were observed to occur in accord with the measured ionizing radiations.

  10. ENVIRONMENTAL EFFECTS OF OZONE DEPLETION AND ITS INTERACTIONS WITH CLIMATE CHANGE: PROGRESS REPORT 2004

    EPA Science Inventory

    The measures needed for the protection of the Earth's ozone layer are decided regularly by the Parties to the Montreal Protocol. This progress report is the 2004 update by the Environmental Effects Assessment Panel.

  11. ENVIRONMENTAL EFFECTS OF OZONE DEPLETION AND ITS INTERACTIONS WITH CLIMATE CHANGE: PROGRESS REPORT 2004

    EPA Science Inventory

    The measures needed for the protection of the Earth's ozone layer are decided regularly by the Parties to the Montreal Protocol. This progress report is the 2004 update by the Environmental Effects Assessment Panel.

  12. Degradation and toxicity depletion of RB19 anthraquinone dye in water by ozone-based technologies.

    PubMed

    Lovato, María E; Fiasconaro, María L; Martín, Carlos A

    2017-02-01

    This research investigated the discoloration and mineralization of Reactive Blue 19 (RB19) anthraquinone dye by single ozonation, single UV radiation and ozonation jointed with UV radiation (O3/UV). The problem was approached from two points of view: with the objective of color removal or the mineralization of solution. In each case, the optimum operating conditions were different. Ozonation was the most effective treatment for color removal, while the combined O3/UV treatment was for mineralization. Major intermediates of the dye degradation were identified by gas chromatography/mass spectrometry and a degradation pathway was proposed. In addition, a clear decrease of the toxicity of the dye was achieved at the end of the experiments. The effect of initial dye concentration, pH, ozone dose, and UV radiation on the degradation of the dye and decrease of total organic carbon was investigated, in order to establish the optimal operating conditions to achieve discoloration, mineralization or a combination of both.

  13. Measurements of total depletion of ozone in the 2010-2011 Arctic winter lower stratosphere by MIPAS/ENVISAT using a 2D tomographic approach

    NASA Astrophysics Data System (ADS)

    Arnone, E.; Castelli, E.; Viscardy, S.; Papandrea, E.; Errera, Q.; Carlotti, M.; Dinelli, B.

    2011-12-01

    We present observations of the 2010-2011 Arctic winter stratosphere from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard ENVISAT. We adopted a full 2D tomographic retrieval approach to account for the strong horizontal inhomogeneity of the atmosphere present under vortex conditions. A well isolated stratospheric vortex extended the PSC season up to middle March, with consequent significant activation of heterogeneous chemistry and ozone destruction. Through inspection of MIPAS spectra, 84% of PSCs were identified as supercooled ternary solution (STS) or STS mixed with nitric acid trihydrate (NAT), 16% formed mostly by NAT particles, and only a few by ice. In the lower stratosphere, vortex average ozone showed a daily depletion rate reaching 100 ppbv/day and absolute values dropping to 0.6 ppmv (corresponding to a chemical loss from early winter greater than 80%). In early April, 10% of vortex measurements at 18 km altitude displayed total depletion of ozone. Ozone loss was accompanied by activation of ClO, associated depletion of its reservoir ClONO2, and significant denitrification which further delayed the recovery of ozone in spring. Compared to MIPAS observed 2003-2010 Arctic winters, the lower stratospheric vortex in March had temperature 15 K lower than average, pressure measurements showed a contraction by up to 20% and HNO3 was 50% lower. This resulted in vortex ozone 50% lower than usual and the largest depletion ever observed.

  14. Ozone depletion in the upper stratosphere estimated from satellite and Space Shuttle data

    NASA Technical Reports Server (NTRS)

    Hilsenrath, Ernest; Cebula, Richard P.; Jackman, Charles H.

    1992-01-01

    Shuttle Solar Backscatter Ultraviolet (SSBUV) spectrometer observations of ozone concentrations in the upper stratosphere made in October 1989 are combined here with measurements made in October 1980 by the similar SBUV instruments on NASA's Nimbus-7 satellite. It is shown that the ozone concentration near 45 km has decreased during this period by about 7 +/- 2 percent. The trend is consistent with predictions of a 2D photochemical model.

  15. Characteristics of tropospheric ozone depletion events in the Arctic spring: analysis of the ARCTAS, ARCPAC, and ARCIONS measurements and satellite BrO observations

    NASA Astrophysics Data System (ADS)

    Koo, J.-H.; Wang, Y.; Kurosu, T. P.; Chance, K.; Rozanov, A.; Richter, A.; Oltmans, S. J.; Thompson, A. M.; Hair, J. W.; Fenn, M. A.; Weinheimer, A. J.; Ryerson, T. B.; Solberg, S.; Huey, L. G.; Liao, J.; Dibb, J. E.; Neuman, J. A.; Nowak, J. B.; Pierce, R. B.; Natarajan, M.; Al-Saadi, J.

    2012-07-01

    Arctic ozone depletion events (ODEs) are due to catalytic ozone loss driven by halogen chemistry. The presence of ODEs is affected not only by in situ chemistry but also by transport including advection of ozone-poor air mass and vertical mixing. To better characterize the ODEs, we analyze the combined set of surface, ozonesonde, and aircraft in situ measurements of ozone and bromine compounds during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) and the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) experiments (April 2008). Tropospheric BrO columns retrieved from satellite measurements and back trajectories calculations are used to investigate the characteristics of observed ODEs. The implications of the analysis results for the validation of the retrieval of tropospheric column BrO are also discussed. Time-lagged correlation analysis between in situ (surface and ozonesonde) measurements of ozone and satellite derived tropospheric BrO indicates that the ODEs are due to either local halogen-driven ozone loss or short-range (~1 day) transport from nearby regions with ozone depletion. The effect of in situ halogen-driven loss is also evident in the diurnal variation of surface ozone concentrations at Alert, Canada. High-BrO regions revealed by satellite measurements tend to be collocated with first-year sea ice, particularly over the Chukchi Sea. Aircraft observations indicate low-ozone air mass transported from these high-BrO regions. Correlation analyses of ozone with potential temperature and time-lagged tropospheric BrO column show that the vertical extent of local ozone loss is surprisingly deep (1-2 km) at Resolute and Churchill, Canada. The unstable boundary layer during ODEs at Churchill could potentially provide a source of free tropospheric BrO through convective transport and explain the significant negative correlation between free tropospheric ozone and tropospheric BrO column

  16. When Will the Antarctic Ozone Hole Recover?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.

    2006-01-01

    The Antarctic ozone hole demonstrates large-scale, man-made affects on our atmosphere. Surface observations now show that human produced ozone depleting substances (ODSs) are declining. The ozone hole should soon start to diminish because of this decline. In this talk we will demonstrate an ozone hole parametric model. This model is based upon: 1) a new algorithm for estimating 61 and Br levels over Antarctica and 2) late-spring Antarctic stratospheric temperatures. This parametric model explains 95% of the ozone hole area's variance. We use future ODS levels to predict ozone hole recovery. Full recovery to 1980 levels will occur in approximately 2068. The ozone hole area will very slowly decline over the next 2 decades. Detection of a statistically significant decrease of area will not occur until approximately 2024. We further show that nominal Antarctic stratospheric greenhouse gas forced temperature change should have a small impact on the ozone hole.

  17. When Will the Antarctic Ozone Hole Recover?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Stephen A.; Schauffler, Sue

    2006-01-01

    The Antarctic ozone hole demonstrates large-scale, man-made affects on our atmosphere. Surface observations now show that human produced ozone depleting substances (ODSs) are declining. The ozone hole should soon start to diminish because of this decline. Herein we demonstrate an ozone hole parametric model. This model is based upon: 1) a new algorithm for estimating C1 and Br levels over Antarctica and 2) late-spring Antarctic stratospheric temperatures. This parametric model explains 95% of the ozone hole area s variance. We use future ODS levels to predict ozone hole recovery. Full recovery to 1980 levels will occur in approximately 2068. The ozone hole area will very slowly decline over the next 2 decades. Detection of a statistically significant decrease of area will not occur until approximately 2024. We further show that nominal Antarctic stratospheric greenhouse gas forced temperature change should have a small impact on the ozone hole.

  18. Spatial- and time-explicit human damage modeling of ozone depleting substances in life cycle impact assessment.

    PubMed

    Struijs, Jaap; van Dijk, Arjan; Slaper, Harry; van Wijnen, Harm J; Velders, Guus J M; Chaplin, George; Huijbregts, Mark A J

    2010-01-01

    Depletion of the stratospheric ozone layer is mainly caused by emissions of persistent halocarbons of anthropogenic origin. The resulting increase of solar ultraviolet radiation at the Earth's surface is associated with increased exposure of humans and increased human health damage. Here we assessed the change in human health damage caused by three types of skin cancer and cataract in terms of (healthy) years of life lost per kiloton emission reduction of an ozone-depleting substance (ODS). This so-called characterization factor is used in Life Cycle Assessments (LCAs). Characterization factors are provided for the emissions of five chlorofluorocarbons, three hydrochlorofluorocarbons, three (bromine-containing) halons, carbon tetrachloride, methyl chloroform, and anthropogenic emissions of methyl bromide. We employed dynamic calculations on a global scale for this purpose, taking physical and social geographic data into account such as skin tones, population density, average age, and life expectancy. When emission rates of all ODSs in 2007 are multiplied by our characterization factors, the resulting number of years of life lost may be a factor of 5 higher than reported previously. This increase is merely explained through the global demographic development until 2100 we took into account.

  19. How realistically does outdoor UV-B supplementation with lamps reflect ozone depletion: an assessment of enhancement errors.

    PubMed

    Kotilainen, Titta; Lindfors, Anders; Tegelberg, Riitta; Aphalo, Pedro J

    2011-01-01

    Limitations in the realism of currently available lamps mean that enhancement errors in outdoor experiments simulating UV-B radiation effects of stratospheric ozone depletion can be large. Here, we assess the magnitude of such errors at two Finnish locations, during May and June, under three cloud conditions. First we simulated solar radiation spectra for normal, compared with 10% and 20% ozone depletion, and convoluted the daily integrated solar spectra with eight biological spectral weighting functions (BSWFs) of relevance to effects of UV on plants. We also convoluted a measured spectrum from cellulose-acetate filtered UV-B lamps with the same eight BSWFs. From these intermediate results we calculated the enhancement errors. Differences between locations and months were small, cloudiness had only a minor effect. This assessment was based on the assumption that no extra enhancement compensating for shading of UV radiation by lamp frames is performed. Under this assumption errors between spectra are due to differences in the UV-B effectiveness rather than differences in the UV-A effectiveness. Hence, conclusions about plant growth from past UV-supplementation experiments should be valid. However, interpretation of the response of individual physiological processes is less secure, so results from some field experiments with lamps might need reassessment.

  20. Depletion of ozone and reservoir species of chlorine and nitrogen oxide in the lower Antarctic polar vortex measured from aircraft

    NASA Astrophysics Data System (ADS)

    Jurkat, T.; Voigt, C.; Kaufmann, S.; Grooß, J.-U.; Ziereis, H.; Dörnbrack, A.; Hoor, P.; Bozem, H.; Engel, A.; Bönisch, H.; Keber, T.; Hüneke, T.; Pfeilsticker, K.; Zahn, A.; Walker, K. A.; Boone, C. D.; Bernath, P. F.; Schlager, H.

    2017-06-01

    Novel airborne in situ measurements of inorganic chlorine, nitrogen oxide species, and ozone were performed inside the lower Antarctic polar vortex and at its edge in September 2012. We focus on one flight during the Transport and Composition of the LMS/Earth System Model Validation (TACTS/ESMVal) campaign with the German research aircraft HALO (High-Altitude LOng range research aircraft), reaching latitudes of 65°S and potential temperatures up to 405 K. Using the early winter correlations of reactive trace gases with N2O from the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS), we find high depletion of chlorine reservoir gases up to ˜40% (0.8 ppbv) at 12 km to 14 km altitude in the vortex and 0.4 ppbv at the edge in subsided stratospheric air with mean ages up to 4.5 years. We observe denitrification of up to 4 ppbv, while ozone was depleted by 1.2 ppmv at potential temperatures as low as 380 K. The advanced instrumentation aboard HALO enables high-resolution measurements with implications for the oxidation capacity of the lowermost stratosphere.

  1. New methodology for Ozone Depletion Potentials of short-lived compounds: n-Propyl bromide as an example

    NASA Astrophysics Data System (ADS)

    Wuebbles, Donald J.; Patten, Kenneth O.; Johnson, Matthew T.; Kotamarthi, Rao

    2001-07-01

    A number of the compounds proposed as replacements for substances controlled under the Montreal Protocol have extremely short atmospheric lifetimes, on the order of days to a few months. An important example is n-propyl bromide (also referred to as 1-bromopropane, CH2BrCH2CH3 or simplified as 1-C3H7Br or nPB). This compound, useful as a solvent, has an atmospheric lifetime of less than 20 days due to its reaction with hydroxyl. Because nPB contains bromine, any amount reaching the stratosphere has the potential to affect concentrations of stratospheric ozone. The definition of Ozone Depletion Potentials (ODP) needs to be modified for such short-lived compounds to account for the location and timing of emissions. It is not adequate to treat these chemicals as if they were uniformly emitted at all latitudes and longitudes as normally done for longer-lived gases. Thus, for short-lived compounds, policymakers will need a table of ODP values instead of the single value generally provided in past studies. This study uses the MOZART2 three-dimensional chemical-transport model in combination with studies with our less computationally expensive two-dimensional model to examine potential effects of nPB on stratospheric ozone. Multiple facets of this study examine key questions regarding the amount of bromine reaching the stratosphere following emission of nPB. Our most significant findings from this study for the purposes of short-lived replacement compound ozone effects are summarized as follows. The degradation of nPB produces a significant quantity of bromoacetone which increases the amount of bromine transported to the stratosphere due to nPB. However, much of that effect is not due to bromoacetone itself, but instead to inorganic bromine which is produced from tropospheric oxidation of nPB, bromoacetone, and other degradation products and is transported above the dry and wet deposition processes of the model. The MOZART2 nPB results indicate a minimal correction of the

  2. A Model of the Effect of Ozone Depletion on Lower-Stratospheric Structure

    NASA Technical Reports Server (NTRS)

    Olsen, Mark A.; Stolarski, Richard S.; Gupta, Mohan L.; Nielsen, J. Eric; Pawson, Steven

    2005-01-01

    We have run two twenty-year integrations of a global circulation model using 1978-1980 and 1998-2000 monthly mean ozone climatologies. The ozone climatology is used solely in the radiation scheme of the model. Several key differences between the model runs will be presented. The temperature and potential vorticity (PV) structure of the lower stratosphere, particularly in the Southern Hemisphere, is significantly changed using the 1998-2000 ozone climatology. In the Southern Hemisphere summer, the lapse rate and PV-defined polar tropopauses are both at altitudes on the order of several hundred meters greater than the 1978-1980 climatological run. The 380 K potential temperature surf= is likewise at a greater altitude. The mass of the extratropical lowermost stratosphere (between the tropopause and 380 K surface) remains unchanged. The altitude differences are not observed in the Northern Hemisphere. The different ozone fields do not produce a significant change in the annual extratropical stratosphere-troposphere exchange of mass although slight variations in the spatial distribution of the exchange exist. We are also investigating a delay in the breakup of the Southern Hemisphere polar vortex due to the differing ozone climatologies.

  3. Laboratory Investigations of Heterogeneous Chemistry Important to Ozone Depletion in the Stratosphere

    NASA Astrophysics Data System (ADS)

    Zhang, Renyi

    Results of laboratory investigations of heterogeneous chemistry important to ozone depletion in the stratosphere are presented. Thermodynamic properties (such as melting points, enthalpies of fusion, etc.) for acids which are present in the stratosphere (HCl, HNO_3 , and H_2SO_4 ) are studied using laboratory-assembled apparatus of electrical conductivity and differential thermal analysis and using a commercial differential scanning calorimeter (DSC). Vapor pressures and infrared spectra of liquid and supercooled solutions, and of liquid-solid and solid -solid coexistence mixtures for the HCl/H_2 O and H_2SO_4 /H_2O binary systems are investigated. Equilibrium constants and standard enthalpies of formation for the pure crystalline hydrates of those acids as well as their corresponding liquid compositions are determined from the vapor pressure and calorimetric data. A theoretical approach, which allows determination of vapor pressures for two adjacent hydrates in thermodynamic equilibrium and for the coexistence systems involving a hydrate and ice in a binary system, is presented in terms of chemical equilibrium principles and compared with the experimental data for thermodynamic consistence. Vapor pressures of HNO_3 and HCl over H_2SO_4 /HNO_3/H_2 O and H_2SO_4 /HCl/H_2O solutions as well as over H_2SO_4/HNO _3/HCl/H_2O solutions are also measured in order to predict incorporation of stratospheric acids into the background sulfate aerosols. From the data, the Henry's law solubility constants for those systems are determined and the equilibrium compositions of aqueous stratospheric aerosols are predicted as a function of ambient temperature and mixing ratios of H_2 O and HNO_3. The results indicate that at the low temperatures characteristic of the stratosphere at high latitudes in the winter and spring, the HNO_3 content reaches levels of the order of 10% wt in the background sulfate aerosols. The results also reveal that the amount of dissolved HCl in the

  4. Robust impact of coupled stratospheric ozone chemistry on the response of the Austral circulation to increased greenhouse gases

    NASA Astrophysics Data System (ADS)

    Chiodo, G.; Polvani, L. M.

    2016-12-01

    Due to computational constraints, interactive stratospheric chemistry is commonly neglected in most GCMs participating in inter-comparison projects. The impact of this simplification on the modeled response to external forcings remains largely unexplored. In this work, we examine the impact of the stratospheric chemistry coupling on the SH circulation response to an abrupt quadrupling of CO2. We accomplish this with a version of the Whole Atmosphere Community Climate (WACCM) model, which allows coupling and de-coupling stratospheric chemistry, without altering any other physical parameterization. We find that the chemistry coupling in WACCM significantly reduces (by about 20%) the response of both eddy-driven mid-latitude jet and the Hadley Cell strength, without altering the surface temperature response. This behavior is linked to the representation of stratospheric ozone, and its effects on the meridional temperature gradient at the extratropical tropopause. Our results imply that neglecting stratospheric ozone chemistry results in a potential overestimation of the circulation response to GHGs. Hence, stratospheric ozone chemistry produces a substantial negative feedback on the response of the atmospheric circulation to increased greenhouse gases.

  5. Atmospheric chemistry of short-chain haloolefins: photochemical ozone creation potentials (POCPs), global warming potentials (GWPs), and ozone depletion potentials (ODPs).

    PubMed

    Wallington, T J; Sulbaek Andersen, M P; Nielsen, O J

    2015-06-01

    Short-chain haloolefins are being introduced as replacements for saturated halocarbons. The unifying chemical feature of haloolefins is the presence of a CC double bond which causes the atmospheric lifetimes to be significantly shorter than for the analogous saturated compounds. We discuss the atmospheric lifetimes, photochemical ozone creation potentials (POCPs), global warming potentials (GWPs), and ozone depletion potentials (ODPs) of haloolefins. The commercially relevant short-chain haloolefins CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) have short atmospheric lifetimes (days to weeks), negligible POCPs, negligible GWPs, and ODPs which do not differ materially from zero. In the concentrations expected in the environment their atmospheric degradation products will have a negligible impact on ecosystems. CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) are environmentally acceptable.

  6. Evaluating the importance of innovative heterogeneous chemistry to explain observed stratospheric ozone depletion

    SciTech Connect

    Kinnison, D.E.; Connell, P.S.

    1996-02-27

    Currently, there is a widespread search for additional heterogeneous reactions or combination of heterogeneous and homogeneous (gas-phase) reactions that could catalytically reduce ozone to observed levels. In 1992, Burley and Johnston proposed that nitrosyl sulfuric acid (NSA) NOHSO{sub 4}, is a promising heterogeneous reactant for activating HCl in sulfuric acid particles. They list several sources for producing it in the stratosphere and they carried out thermodynamic and chemical kinetic calculations at one stratospheric altitude and at one latitude. NSA has been overlooked in all previous stratospheric model calculations, even though it has been observed in stratospheric sulfate aerosols. This study makes large scale atmospheric model calculations to test the proposal by Burley and Johnston that a promising heterogeneous process for activating HCl in sulfuric acid particles is a catalytic coupled based on nitrosyl sulfuric acid (NSA). This mechanism is examined under non-volcanic and volcanic conditions representative of the recent eruption of Mt. Pinatubo. The calculations set firm limits on the range of kinetic parameters over which this heterogeneous processes would be important in the global ozone balance, and thus is a guide for where laboratory work is needed. In addition, they have derived a preliminary time-dependent integration (1980--1994) to represent the observed trend in ozone. Comparison between model-derived and the observed ozone trend will be compared.

  7. Environmental effects of ozone depletion and its interactions with climate change: Progress report, 2016

    EPA Science Inventory

    When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than previously believed. As a result of this, human health and environmental issues will be longer-lasting and more regionally variable...

  8. Effects of depletion of ascorbic acid or nonprotein sulfhydryls on the acute inhalation toxicity of nitrogen dioxide, ozone, and phosgene

    SciTech Connect

    Slade, R.; Highfill, J.W.; Hatch, G.E.

    1989-01-01

    The effect of depleting lung ascorbic acid (AH{sub 2}) and nonprotein sulfhydryls (NPSH) on the acute inhalation toxicity of nitrogen dioxide (NO{sub 2}), ozone (O{sub 3}), and phosgene (COCl{sub 2}) was investigated in guinea pigs. The increase in bronchoalveolar lavage (BAL) fluid protein (an indicator of alveolar-capillary damage leading to increased permeability) was measured 16 to 18 hr following a 4 hr exposure to the gas in animals deficient in (AH{sub 2}) or NPSH. Gas concentrations were chosen which produced low but significant increases in BAL protein. Lung (AH{sub 2}) was lowered to about 20% of control by feeding rabbit chow for 2 weeks. Lung NPSH was lowered to about 50% of control by injecting a mixture of buthionine S,R-sulfoximine (BSO) and diethylmaleate (DEM) (2.7 and 1.2 mmol/kg respectively). BSO/DEM did not affect the lung concentrations of (AH{sub 2}) or alpha-tocopherol. AH{sub 2} depletion caused a 6 fold and a 3 fold enhancement in the toxicity of 5 ppm and 10 ppm (NO{sub 2}), and a 6 fold enhancement in the toxicity of 0.5 ppm (O{sub 3}), but did not affect toxicity of 1.0 ppm (O{sub 3}). AH{sub 2} depletion did not affect phosgene toxicity (at 0.25 ppm and 0.5 ppm).

  9. UV-B radiation arising from stratospheric ozone depletion influences the pigmentation of the Antarctic moss Andreaea regularis.

    PubMed

    Newsham, K K

    2003-05-01

    Changes to the radiative environment arising from stratospheric ozone (O(3)) depletion and subsequent associations between these changes and the pigmentation of the moss Andreaea regularis were measured in late austral spring and early summer 1998 at Rothera Point on the western Antarctic Peninsula (67 degrees S, 68 degrees W). A strong relationship between O(3) column depth and the ratio of UV-B to PAR irradiance ( F(uv-b)/ F(par)) was recorded at ground level ( r(2)=92%, P<0.001). Weaker, but significant, associations between O(3) column depth and ground level unweighted and biologically effective UV-B radiation (UV-B(be)) were also found. Regression analyses indicated that F(uv-b)/ F(par) was the best predictor for concentrations of UV-B screening pigments and total carotenoids extracted from plant tissues. Concentrations of these pigments were loosely ( r(2)= ca. 30%) but significantly ( P<0.01) positively associated with F(uv-b)/ F(par). Concentrations of UV-B screening pigments were also positively associated with irradiances and daily doses of unweighted UV-B and UV-B(be) radiation. The concentrations of chlorophylls a and b were apparently unaffected by O(3) depletion. The data derived from this study suggest that changes to the radiative environment associated with stratospheric O(3) depletion influence the pigmentation of A. regularis. As a corollary, flavonoids are shown to be present in tissues of A. regularis.

  10. Ozone pollution effects on the land carbon sink in the future greenhouse world

    NASA Astrophysics Data System (ADS)

    Unger, N.; Yue, X.

    2015-12-01

    Ozone pollution has huge impacts on the carbon balance in the United States, Europe and China. While terrestrial ecosystems provide an important sink for surface ozone through stomatal uptake, this process damages photosynthesis, reduces plant growth and biomass accumulation, and affects stomatal control over plant transpiration of water vapor. Effective mitigation of climate change by stabilizing atmospheric carbon dioxide concentrations requires improved understanding of ozone effects on the land carbon sink. Future effects of ozone pollution on the land carbon sink are largely unknown. We apply multiple observational datasets in combination with the Yale Interactive Terrestrial Biosphere (YIBs) model to quantify ozone vegetation damage in the present climatic state and for a broad range of possible futures. YIBs includes a mechanistic ozone damage model that affects both photosynthetic rate and stomatal conductance for low or high ozone plant sensitivity. YIBs is embedded in the NASA GISS ModelE2 global chemistry-climate model to allow a uniquely informed integration of plant physiology, atmospheric chemistry, and climate. The YIBs model has been extensively evaluated using land carbon flux measurements from 145 flux tower sites and multiple satellite products. Chronic ozone exposure in the present day reduces GPP by 11-23%, NPP by 8-16%, stomatal conductance by 8-17% and leaf area index by 2-5% in the summer time eastern United States. Similar response magnitudes are found in Europe but almost doubled damage effects occur in hotspots in eastern China. We investigate future ozone vegetation damage within the context of multiple global change drivers (physical climate change, carbon dioxide fertilization, human energy and agricultural emissions, human land use) at 2050 following the IPCC RCP2.6 and RCP8.5 scenarios. In the RCP8.5 world at 2050, growing season average GPP and NPP are reduced by 20-40% in China and 5-20% in the United States due to the global rise

  11. Future Climate Impacts of Direct Radiative Forcing Anthropogenic Aerosols, Tropospheric Ozone, and Long-lived Greenhouse Gases

    NASA Technical Reports Server (NTRS)

    Chen, Wei-Ting; Liao, Hong; Seinfeld, John H.

    2007-01-01

    Long-lived greenhouse gases (GHGs) are the most important driver of climate change over the next century. Aerosols and tropospheric ozone (O3) are expected to induce significant perturbations to the GHG-forced climate. To distinguish the equilibrium climate responses to changes in direct radiative forcing of anthropogenic aerosols, tropospheric ozone, and GHG between present day and year 2100, four 80-year equilibrium climates are simulated using a unified tropospheric chemistry-aerosol model within the Goddard Institute for Space Studies (GISS) general circulation model (GCM) 110. Concentrations of sulfate, nitrate, primary organic (POA) carbon, secondary organic (SOA) carbon, black carbon (BC) aerosols, and tropospheric ozone for present day and year 2100 are obtained a priori by coupled chemistry-aerosol GCM simulations, with emissions of aerosols, ozone, and precursors based on the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenario (SRES) A2. Changing anthropogenic aerosols, tropospheric ozone, and GHG from present day to year 2100 is predicted to perturb the global annual mean radiative forcing by +0.18 (considering aerosol direct effects only), +0.65, and +6.54 W m(sup -2) at the tropopause, and to induce an equilibrium global annual mean surface temperature change of +0.14, +0.32, and +5.31 K, respectively, with the largest temperature response occurring at northern high latitudes. Anthropogenic aerosols, through their direct effect, are predicted to alter the Hadley circulation owing to an increasing interhemispheric temperature gradient, leading to changes in tropical precipitation. When changes in both aerosols and tropospheric ozone are considered, the predicted patterns of change in global circulation and the hydrological cycle are similar to those induced by aerosols alone. GHG-induced climate changes, such as amplified warming over high latitudes, weakened Hadley circulation, and increasing precipitation over the

  12. Knowledge about the Greenhouse Effect and the Effects of the Ozone Layer among Norwegian Pupils Finishing Compulsory Education in 1989, 1993, and 2005--What Now?

    ERIC Educational Resources Information Center

    Hansen, Pal J. Kirkeby

    2010-01-01

    The greenhouse effect and the effects of the ozone layer have been in the media and public focus for more than two decades. During the same period, Norwegian compulsory schools have had four national curricula. The two last-mentioned prescribe explicitly the two topics. Media and public discourse might have been sources of information causing…

  13. Knowledge about the Greenhouse Effect and the Effects of the Ozone Layer among Norwegian Pupils Finishing Compulsory Education in 1989, 1993, and 2005--What Now?

    ERIC Educational Resources Information Center

    Hansen, Pal J. Kirkeby

    2010-01-01

    The greenhouse effect and the effects of the ozone layer have been in the media and public focus for more than two decades. During the same period, Norwegian compulsory schools have had four national curricula. The two last-mentioned prescribe explicitly the two topics. Media and public discourse might have been sources of information causing…

  14. Effects of cosmic rays on atmospheric chlorofluorocarbon dissociation and ozone depletion.

    PubMed

    Lu, Q B; Sanche, L

    2001-08-13

    Data from satellite, balloon, and ground-station measurements show that ozone loss is strongly correlated with cosmic-ray ionization-rate variations with altitude, latitude, and time. Moreover, our laboratory data indicate that the dissociation induced by cosmic rays for CF(2)Cl(2) and CFCl(3) on ice surfaces in the polar stratosphere at an altitude of approximately 15 km is quite efficient, with estimated rates of 4.3 x 10(-5) and 3.6 x 10(-4) s(-1), respectively. These findings suggest that dissociation of chlorofluorocarbons by capture of electrons produced by cosmic rays and localized in polar stratospheric cloud ice may play a significant role in causing the ozone hole.

  15. Effects of Cosmic Rays on Atmospheric Chlorofluorocarbon Dissociation and Ozone Depletion

    SciTech Connect

    Lu, Q.-B.; Sanche, L.

    2001-08-13

    Data from satellite, balloon, and ground-station measurements show that ozone loss is strongly correlated with cosmic-ray ionization-rate variations with altitude, latitude, and time. Moreover, our laboratory data indicate that the dissociation induced by cosmic rays for CF{sub 2}Cl {sub 2} and CFCl{sub 3} on ice surfaces in the polar stratosphere at an altitude of {approx}15 km is quite efficient, with estimated rates of 4.3 x 10{sup -5} and 3.6 x 10{sup -4} s{sup -1}, respectively. These findings suggest that dissociation of chlorofluorocarbons by capture of electrons produced by cosmic rays and localized in polar stratospheric cloud ice may play a significant role in causing the ozone hole.

  16. A contribution toward understanding the biospherical significance of Antarctic ozone depletion

    NASA Technical Reports Server (NTRS)

    Lubin, Dan; Mitchell, Greg; Frederick, John E.; Alberts, Amy D.; Booth, C. R.; Lucas, Timothy; Neuschuler, David

    1992-01-01

    The paper presents and compares measurements of biologically active UV radiation made by the NSF scanning spectroradiometer (UV-monitor) at Palmer Station, Antarctica, during the Austral springs of 1988, 1989, and 1990. Column ozone abundance above Palmer Station is computed from these measurements using a multiple wavelength algorithm. Two contrasting action spectra are employed to estimate the biologically relevant dose from the spectral measurements: a standard weighting function for damage to DNA, and a new action spectrum representing the potential for photosynthesis inhibition in Antarctic phytoplankton. The former weights only UV-B wavelengths (280-320 nm) and gives the most weight to wavelengths shorter than 300 nm, while the latter includes large contributions out to 355 nm. Ozone abundances and dose-weighted irradiances provided by the NSF UV-monitor are used to derive the radiation amplification factors for both DNA- and phytoplankton-effective irradiance.

  17. Evaluation of Non-Ozone-Depleting-Chemical Cleaning Methods for Space Mechanisms Using a Vacuum Spiral Orbit Rolling Contact Tribometer

    NASA Technical Reports Server (NTRS)

    Jansen, Mark J.; Jones, William R., Jr.; Wheeler, Donald R.; Keller, Dennis J.

    2000-01-01

    Because CFC 113, an ozone depleting chemical (ODC), can no longer be produced, alternative bearing cleaning methods must be studied. The objective of this work was to study the effect of the new cleaning methods on lubricant lifetime using a vacuum bearing simulator (spiral orbit rolling contact tribometer). Four alternative cleaning methods were studied: ultra-violet (UV) ozone, aqueous levigated alumina slurry (ALAS), super critical fluid (SCF) CO2 and aqueous Brulin 815GD. Baseline tests were done using CFC 113. Test conditions were the following: a vacuum of at least 1.3 x 10(exp -6) Pa, 440C steel components, a rotational speed of 10 RPM, a lubricant charge of between 60-75 micrograms, a perfluoropolyalkylether lubricant (Z-25), and a load of 200N (44.6 lbs., a mean Hertzian stress of 1.5 GPa). Normalized lubricant lifetime was determined by dividing the total number of ball orbits by the amount of lubricant. The failure condition was a friction coefficient of 0.38. Post-test XPS analysis was also performed, showing slight variations in post-cleaning surface chemistry. Statistical analysis of the resultant data was conducted and it was determined that the data sets were most directly comparable when subjected to a natural log transformation. The natural log life (NL-Life) data for each cleaning method were reasonably normally (statistically) distributed and yielded standard deviations that were not significantly different among the five cleaning methods investigated. This made comparison of their NL-Life means very straightforward using a Bonferroni multiple comparison of means procedure. This procedure showed that the ALAS, UV-ozone and CFC 113 methods were not statistically significantly different from one another with respect to mean NL-Life. It also found that the SCF CO2 method yielded a significantly higher mean NL-Life than the mean NL-Lives of the ALAS, UV-ozone and CFC 113 methods. It also determined that the aqueous Brulin 815GD method yielded a mean

  18. When will the Antarctic ozone hole recover?

    NASA Astrophysics Data System (ADS)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Stephen A.; Schauffler, Sue M.

    2006-06-01

    The Antarctic ozone hole demonstrates large-scale, man-made affects on our atmosphere. Surface observations now show that human produced ozone-depleting substances (ODSs) are declining. The ozone hole should soon start to diminish because of this decline. We demonstrate a parametric model of ozone hole area that is based upon a new algorithm for estimating chlorine and bromine levels over Antarctica and late spring Antarctic stratospheric temperatures. This model explains 95% of the ozone hole area's variance. We then use future ODS levels to predict ozone hole recovery. Full recovery to 1980 levels will occur around 2068 and the area will very slowly decline between 2001 and 2017. Detection of a statistically significant decrease of area will not occur until about 2024. We further show that nominal Antarctic stratospheric greenhouse gas forced temperature change should have a small impact on the ozone hole.

  19. A probabilistic study of the return of stratospheric ozone to 1960 levels

    NASA Astrophysics Data System (ADS)

    Södergren, A. Helena; Bodeker, Gregory E.; Kremser, Stefanie; Meinshausen, Malte; McDonald, Adrian J.

    2016-09-01

    Anthropogenic emissions of greenhouse gases and ozone-depleting substances are expected to continue to affect concentrations of ozone in the stratosphere through the 21st century. While a range of estimates for when stratospheric ozone is expected to return to unperturbed levels is available in the literature, quantification of the spread in results is sparse. Here we present the first probabilistic study of latitudinally resolved years of return of stratospheric ozone to 1960 levels. Results from our 180-member ensemble, simulated with a newly developed simple climate model, suggest that the spread in return years of ozone is largest around 40°N/S and in the southern high latitudes and decreases with increasing greenhouse gas emissions. The spread in projections of ozone is larger for higher greenhouse gas scenarios and is larger in the polar regions than in the midlatitudes, while the spread in ozone radiative forcing is smallest in the polar regions.

  20. Characteristics of tropospheric ozone depletion events in the Arctic spring: analysis of the ARCTAS, ARCPAC, and ARCIONS measurements and satellite BrO observations

    NASA Astrophysics Data System (ADS)

    Koo, J.-H.; Wang, Y.; Kurosu, T. P.; Chance, K.; Rozanov, A.; Richter, A.; Oltmans, S. J.; Thompson, A. M.; Hair, J. W.; Fenn, M. A.; Weinheimer, A. J.; Ryerson, T. B.; Solberg, S.; Huey, L. G.; Liao, J.; Dibb, J. E.; Neuman, J. A.; Nowak, J. B.; Pierce, R. B.; Natarajan, M.; Al-Saadi, J.

    2012-10-01

    Arctic ozone depletion events (ODEs) are caused by halogen catalyzed ozone loss. In situ chemistry, advection of ozone-poor air mass, and vertical mixing in the lower troposphere are important factors affecting ODEs. To better characterize the ODEs, we analyze the combined set of surface, ozonesonde, and aircraft in situ measurements of ozone and bromine compounds during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS), the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC), and the Arctic Intensive Ozonesonde Network Study (ARCIONS) experiments (April 2008). Tropospheric BrO columns retrieved from satellite measurements and back trajectory calculations are also used to investigate the characteristics of observed ODEs. In situ observations from these field experiments are inadequate to validate tropospheric BrO columns derived from satellite measurements. In view of this difficulty, we construct an ensemble of tropospheric column BrO estimates from two satellite (OMI and GOME-2) measurements and with three independent methods of calculating stratospheric BrO columns. Furthermore, we select analysis methods that do not depend on the absolute magnitude of column BrO, such as time-lagged correlation analysis of ozone and tropospheric column BrO, to understand characteristics of ODEs. Time-lagged correlation analysis between in situ (surface and ozonesonde) measurements of ozone and satellite derived tropospheric BrO columns indicates that the ODEs are due to either local halogen-driven ozone loss or short-range (∼1 day) transport from nearby regions with ozone depletion. The effect of in situ ozone loss is also evident in the diurnal variation difference between low (10th and 25th percentiles) and higher percentiles of surface ozone concentrations at Alert, Canada. Aircraft observations indicate low-ozone air mass transported from adjacent high-BrO regions. Correlation analyses of ozone with

  1. The GEOS Chemistry Climate Model: Implications of Climate Feedbacks on Ozone Depletion and Recovery

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Pawson, Steven; Douglass, Anne R.; Newman, Paul A.; Kawa, S. Randy; Nielsen, J. Eric; Rodriquez, Jose; Strahan, Susan; Oman, Luke; Waugh, Darryn

    2008-01-01

    The Goddard Earth Observing System Chemistry Climate Model (GEOS CCM) has been developed by combining the atmospheric chemistry and transport modules developed over the years at Goddard and the GEOS general circulation model, also developed at Goddard. The first version of the model was used in the CCMVal intercomparison exercises that contributed to the 2006 WMO/UNEP Ozone Assessment. The second version incorporates the updated version of the GCM (GEOS 5) and will be used for the next round of CCMVal evaluations and the 2010 Ozone Assessment. The third version, now under development, incorporates the combined stratosphere and troposphere chemistry package developed under the Global Modeling Initiative (GMI). We will show comparison to past observations that indicate that we represent the ozone trends over the past 30 years. We will also show the basic temperature, composition, and dynamical structure of the simulations. We will further show projections into the future. We will show results from an ensemble of transient and time-slice simulations, including simulations with fixed 1960 chlorine, simulations with a best guess scenario (Al), and simulations with extremely high chlorine loadings. We will discuss planned extensions of the model to include emission-based boundary conditions for both anthropogenic and biogenic compounds.

  2. The GEOS Chemistry Climate Model: Implications of Climate Feedbacks on Ozone Depletion and Recovery

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Pawson, Steven; Douglass, Anne R.; Newman, Paul A.; Kawa, S. Randy; Nielsen, J. Eric; Rodriquez, Jose; Strahan, Susan; Oman, Luke; Waugh, Darryn

    2008-01-01

    The Goddard Earth Observing System Chemistry Climate Model (GEOS CCM) has been developed by combining the atmospheric chemistry and transport modules developed over the years at Goddard and the GEOS general circulation model, also developed at Goddard. The first version of the model was used in the CCMVal intercomparison exercises that contributed to the 2006 WMO/UNEP Ozone Assessment. The second version incorporates the updated version of the GCM (GEOS 5) and will be used for the next round of CCMVal evaluations and the 2010 Ozone Assessment. The third version, now under development, incorporates the combined stratosphere and troposphere chemistry package developed under the Global Modeling Initiative (GMI). We will show comparison to past observations that indicate that we represent the ozone trends over the past 30 years. We will also show the basic temperature, composition, and dynamical structure of the simulations. We will further show projections into the future. We will show results from an ensemble of transient and time-slice simulations, including simulations with fixed 1960 chlorine, simulations with a best guess scenario (Al), and simulations with extremely high chlorine loadings. We will discuss planned extensions of the model to include emission-based boundary conditions for both anthropogenic and biogenic compounds.

  3. Ultraviolet-radiation and skin cancer. Effect of an ozone layer depletion.

    PubMed

    Henriksen, T; Dahlback, A; Larsen, S H; Moan, J

    1990-05-01

    The effect of changes in the ozone layer on the incidence of skin cancer was explored using data for Norway. Attempts were made to arrive at a relationship between the "environmental effective UV-dose" and the skin cancer incidence. Norway is well suited for this purpose because of the large variation in the annual UV-dose from north to south. Furthermore we have a well developed cancer registry and a homogeneous population with regard to skin type. Four different regions of the country, each with a broadness of 1 degree in latitude (approximately 111 km), were selected (located around 69.5, 63.5, 60 and 58.5 degrees N). The annual effective UV-doses for these regions were calculated, assuming normal ozone conditions throughout the year and the action spectrum proposed by CIE, which extends up to 400 nm. The incidence rate (in the period 1970-1980) of malignant melanoma and non-melanoma skin cancer (mainly basal cell carcinoma) increased with the annual environmental UV-doses. For both these types of cancer a quadratic dose-effect relationship seems to be valid to a first approximation. The present data indicate that the incidence of skin cancer would increase by approximately 2% for each percent ozone reduction.

  4. Effects of solar ultraviolet radiation on antarctic phytoplankton during springtime ozone depletion

    SciTech Connect

    Villafane, V.E.; Helbling, E.W.; Holm-Hansen, O.

    1994-12-31

    In recent years, much attention has been given to the formation of the seasonal ozone {open_quotes}hole{close_quotes} over Antarctica, with the concomitant increase in ultraviolet-B [UV-B, 280-320-nanometer (nm)] radiation levels. The enhanced UV-B radiation can be very damaging to biological systems and has been shown to cause a significant decrease in rates of primary production. This paper describes the impact of {open_quotes}normal{close_quotes} ultraviolet radiation (UVR), as well as enhanced UV-B radiation, on natural assemblages of phytoplankton as well as on just the nanoplankton fraction cells less than 20 micrometers ({mu}m). The studies also included estimation of the impact of UVR as influenced by the taxonomic composition of the phytoplankton and the mitigating effect of cellular UV-absorbing compounds. All studies were carried out at Palmer Station (64.7{degrees}S 64.1{degrees}W) on Anvers Island from early October to the end of December 1993. This period provided excellent opportunities to document the impact of enhanced UV-B radiation on phytoplankton because the ozone hole was very well developed over Palmer Station in the month of October; column ozone concentrations ranged from 140 to 220 Dobson units (DU). 10 refs, 3 figs.

  5. Subsidence of aircraft engine exhaust in the stratosphere: Implications for calculated ozone depletions

    NASA Technical Reports Server (NTRS)

    Rodriguez, J. M.; Shia, R.-L.; Ko, M. K. W.; Heisey, C. W.; Weistenstein, D. K.; Miake-Lye, R. C.; Kolb, C. E.

    1994-01-01

    The deposition altitude of nitrogen oxides and other exhaust species emitted by stratospheric aircraft is a crucial parameter in determining the impact of these emissions on stratospheric ozone. We have utilized a model for the wake of a High-Speed Civil Transport (HSCT) to estimate the enhancements in water and reductions in ozone in these wakes as a function of time. Radiative calculations indicate differential cooling rates as large as -5K/day at the beginning of the far-wake regime, mostly due to the enhanced water abundance. These cooling rates would imply a net sinking of the wakes of about 1.2 km after three days in the limit of no mixing. Calculated mid-latitude column ozone reductions due to emissions from a Mach 2.4 HSCT would then change from about -1% to -06%. However, more realistic calculations adopting moderate mixing for the wake reduce the net sinking to less than 0.2 km, making the impact of radiative subsidence negligible.

  6. UV action spectra for mammalian systems: their implications for the predicted effects of ozone depletion on skin cancer incidence

    SciTech Connect

    Setlow, R.B.

    1982-01-01

    The predicted environmental effect of UV-B depend on the action spectrum for the response studied. Since such spectra change rapidly - usually decreasing with increasing wavelength - and since the biological effects depend on the product of the action spectrum and the sun's spectrum at the surface of the earth which decreases with decreasing wavelength, a slight change in action spectrum will markedly influence the predicted effects of ozone depletion on biological systems. Thus, the key, but by no means only step in the prediction, is a knowledge of the action spectrum. Unfortunately, it is rare that we know or even hope to know the spectrum for biological systems of interest such as skin cancer induction, nor is it possible to do experiments with solar simulators on many systems. Hence, we must base our predictions on the photobiological properties of simple systems and the knowledge of their action spectra and general biological theories connecting simple cells with higher organisms.

  7. Nitrous Oxides Ozone Destructiveness Under Different Climate Scenarios

    NASA Technical Reports Server (NTRS)

    Kanter, David R.; McDermid, Sonali P.

    2016-01-01

    Nitrous oxide (N2O) is an important greenhouse gas and ozone depleting substance as well as a key component of the nitrogen cascade. While emissions scenarios indicating the range of N2O's potential future contributions to radiative forcing are widely available, the impact of these emissions scenarios on future stratospheric ozone depletion is less clear. This is because N2O's ozone destructiveness is partially dependent on tropospheric warming, which affects ozone depletion rates in the stratosphere. Consequently, in order to understand the possible range of stratospheric ozone depletion that N2O could cause over the 21st century, it is important to decouple the greenhouse gas emissions scenarios and compare different emissions trajectories for individual substances (e.g. business-as-usual carbon dioxide (CO2) emissions versus low emissions of N2O). This study is the first to follow such an approach, running a series of experiments using the NASA Goddard Institute for Space Sciences ModelE2 atmospheric sub-model. We anticipate our results to show that stratospheric ozone depletion will be highest in a scenario where CO2 emissions reductions are prioritized over N2O reductions, as this would constrain ozone recovery while doing little to limit stratospheric NOx levels (the breakdown product of N2O that destroys stratospheric ozone). This could not only delay the recovery of the stratospheric ozone layer, but might also prevent a return to pre-1980 global average ozone concentrations, a key goal of the international ozone regime. Accordingly, we think this will highlight the importance of reducing emissions of all major greenhouse gas emissions, including N2O, and not just a singular policy focus on CO2.

  8. Nitrous Oxides Ozone Destructiveness Under Different Climate Scenarios

    NASA Technical Reports Server (NTRS)

    Kanter, David R.; McDermid, Sonali P.

    2016-01-01

    Nitrous oxide (N2O) is an important greenhouse gas and ozone depleting substance as well as a key component of the nitrogen cascade. While emissions scenarios indicating the range of N2O's potential future contributions to radiative forcing are widely available, the impact of these emissions scenarios on future stratospheric ozone depletion is less clear. This is because N2O's ozone destructiveness is partially dependent on tropospheric warming, which affects ozone depletion rates in the stratosphere. Consequently, in order to understand the possible range of stratospheric ozone depletion that N2O could cause over the 21st century, it is important to decouple the greenhouse gas emissions scenarios and compare different emissions trajectories for individual substances (e.g. business-as-usual carbon dioxide (CO2) emissions versus low emissions of N2O). This study is the first to follow such an approach, running a series of experiments using the NASA Goddard Institute for Space Sciences ModelE2 atmospheric sub-model. We anticipate our results to show that stratospheric ozone depletion will be highest in a scenario where CO2 emissions reductions are prioritized over N2O reductions, as this would constrain ozone recovery while doing little to limit stratospheric NOx levels (the breakdown product of N2O that destroys stratospheric ozone). This could not only delay the recovery of the stratospheric ozone layer, but might also prevent a return to pre-1980 global average ozone concentrations, a key goal of the international ozone regime. Accordingly, we think this will highlight the importance of reducing emissions of all major greenhouse gas emissions, including N2O, and not just a singular policy focus on CO2.

  9. Ozone

    MedlinePlus

    ... reactive form of oxygen. In the upper atmosphere, ozone forms a protective layer that shields us from the sun’s ultraviolet rays. At ground level, ozone is a harmful air pollutant and a primary ...

  10. Three-dimensional model evaluation of the Ozone Depletion Potentials for n-propyl bromide, trichloroethylene and perchloroethylene

    NASA Astrophysics Data System (ADS)

    Wuebbles, D. J.; Patten, K. O.; Wang, D.; Youn, D.; Martínez-Avilés, M.; Francisco, J. S.

    2011-03-01

    The existing solvents trichloroethylene (TCE) and perchloroethylene (PCE) and proposed solvent n-propyl bromide (nPB) have atmospheric lifetimes from days to a few months, but contain chlorine or bromine that could affect stratospheric ozone. Several previous studies estimated the Ozone Depletion Potentials (ODPs) for various assumptions of nPB emissions location, but these studies used simplified modeling treatments. The primary purpose of this study is to reevaluate the ODP for n-propyl bromide (nPB) using a current-generation chemistry-transport model of the troposphere and stratosphere. For the first time, ODPs for TCE and PCE are also evaluated in a three-dimensional, global atmospheric chemistry-transport model. Emissions representing industrial use of each compound are incorporated on land surfaces from 30° N to 60° N. The atmospheric chemical lifetime obtained for nPB is 24.7 days, similar to past literature, but the ODP is 0.0049, lower than in our past study of nPB. The derived atmospheric lifetime for TCE is 13.0 days and for PCE is 111 days. The corresponding ODPs are 0.00037 and 0.0050, respectively.

  11. Three-dimensional model evaluation of the Ozone Depletion Potentials for n-propyl bromide, trichloroethylene and perchloroethylene

    NASA Astrophysics Data System (ADS)

    Wuebbles, D. J.; Patten, K. O.; Wang, D.; Youn, D.; Martínez-Avilés, M.; Francisco, J. S.

    2010-07-01

    The existing solvents trichloroethylene (TCE) and perchloroethylene (PCE) and proposed solvent n-propyl bromide (nPB) have atmospheric lifetimes from days to a few months, but contain chlorine or bromine that could affect stratospheric ozone. Several previous studies estimated the Ozone Depletion Potentials (ODPs) for various assumptions for location of nPB emissions, but these studies used simplified modeling treatments. The primary purpose of this study is to reevaluate the ODP for nPB using a current-generation chemistry-transport model of the troposphere and stratosphere. For the first time, ODPs for TCE and PCE are also evaluated. Emissions representing industrial use of each compound are incorporated on land surfaces from 30° N to 60° N. The atmospheric chemical lifetime obtained for nPB is 24.7 days, similar to past literature, but the ODP is 0.0049, lower than in past studies. The derived atmospheric lifetime for TCE is 13.0 days and for PCE is 111 days. The corresponding ODPs are 0.00035 and 0.0060, respectively.

  12. The Nature of Relationships among the Components of Pedagogical Content Knowledge of Preservice Science Teachers: "Ozone Layer Depletion" as an Example

    ERIC Educational Resources Information Center

    Kaya, Osman N.

    2009-01-01

    The purpose of this study was to explore the relationships among the components of preservice science teachers' (PSTs) pedagogical content knowledge (PCK) involving the topic "ozone layer depletion". An open-ended survey was first administered to 216 PSTs in their final year at the Faculty of Education to determine their subject matter…

  13. The Nature of Relationships among the Components of Pedagogical Content Knowledge of Preservice Science Teachers: "Ozone Layer Depletion" as an Example

    ERIC Educational Resources Information Center

    Kaya, Osman N.

    2009-01-01

    The purpose of this study was to explore the relationships among the components of preservice science teachers' (PSTs) pedagogical content knowledge (PCK) involving the topic "ozone layer depletion". An open-ended survey was first administered to 216 PSTs in their final year at the Faculty of Education to determine their subject matter…

  14. Ozone

    MedlinePlus

    Ozone is a gas. It can be good or bad, depending on where it is. "Good" ozone occurs naturally about 10 to 30 miles above ... the sun's ultraviolet rays. Part of the good ozone layer is gone. Man-made chemicals have destroyed ...

  15. Ozone treatment and the depletion of detectable pharmaceuticals and atrazine herbicide in drinking water sourced from the upper Detroit River, Ontario, Canada.

    PubMed

    Hua, Wenyi; Bennett, Erin R; Letcher, Robert J

    2006-07-01

    The depletion and degradation of pharmacologically active compounds (PhACs) and pesticides as a function of ozonation in drinking water treatment processes is not well studied. The A.H. Weeks drinking water treatment plant (DWTP) serves the City of Windsor, Ontario Canada, and incorporates ozone treatment into the production of drinking water. This DWTP also operates a real-time, scaled down pilot plant, which has two parallel streams, conventional and ozone plus conventional treatments. In this study water samples were collected from key points in the two streams of the pilot plant system to determine the depletion and influence of seasonal changes in water processing parameters on eighteen major PhACs (and metabolites) and seven s-triazines herbicides. However, only carbamazepine (antiepileptic), caffeine (stimulant), cotinine (metabolite of nicotine) and atrazine were consistently detectable in the raw water intake (low to sub-ng/L level). Regardless of the seasonality, the flocculation-coagulation and dual media filtration steps without ozone treatment resulted in no decrease in analyte concentrations, while decreases of 66-100% (undetectable, method detection limits 0.05-1 ng/L) of the analyte concentrations were observed when ozone treatment was part of the water processing. These findings demonstrate that ozone treatment is highly effective in depleting carbamazepine, caffeine, cotinine, and atrazine, and thus is highly influential in the fate of these compounds in drinking water treatment regardless of the seasonal time frame. Currently very few Canadian DWTPs incorporate ozonation into conventional treatment, which suggests that human exposure to these compounds via drinking water consumption may be an issue in affected communities.

  16. The Hole in the Ozone Layer.

    ERIC Educational Resources Information Center

    Hamers, Jeanne S.; Jacob, Anthony T.

    This document contains information on the hole in the ozone layer. Topics discussed include properties of ozone, ozone in the atmosphere, chlorofluorocarbons, stratospheric ozone depletion, effects of ozone depletion on life, regulation of substances that deplete the ozone layer, alternatives to CFCs and Halons, and the future of the ozone layer.…

  17. The Hole in the Ozone Layer.

    ERIC Educational Resources Information Center

    Hamers, Jeanne S.; Jacob, Anthony T.

    This document contains information on the hole in the ozone layer. Topics discussed include properties of ozone, ozone in the atmosphere, chlorofluorocarbons, stratospheric ozone depletion, effects of ozone depletion on life, regulation of substances that deplete the ozone layer, alternatives to CFCs and Halons, and the future of the ozone layer.…

  18. Spatial variation of ozone depletion rates in the springtime antarctic polar vortex

    SciTech Connect

    Yung, Y.L.; Allen, M.; Crisp, D.; Zurek, R.W.; Sander, S.P. )

    1990-05-11

    An area-mapping technique, designed to filter out synoptic perturbations of the Antarctic polar vortex such as distortion or displacement away from the pole, was applied to the Nimbus-7 TOMS (Total Ozone Mapping Spectrometer) data. This procedure reveals the detailed morphology of the temporal evolution of column O{sub 3}. The results for the austral spring of 1987 suggest the existence of a relatively stable collar region enclosing an interior that is undergoing large variations. There is tentative evidence for quasi-periodic O{sub 3} fluctuations in the collar and for upwelling of tropospheric air in late spring. A simplified photochemical model of O{sub 3} loss and the temporal evolution of the area-mapped polar O{sub 3} are used to constrain the chlorine monoxide (ClO) concentrations in the springtime Antarctic vortex. The concentrations required to account for the observed loss of O{sub 3} are higher than those previously reported by Anderson et al. but are comparable to their recently revised values. However, the O{sub 3} loss rates could be larger than deduced here because of underestimates of total O{sub 3} by TOMS near the terminator. This uncertainty, together with the uncertainties associated with measurements acquired during the Airborne Antarctic Ozone Experiment, suggests that in early spring, closer to the vortex center, there may be even larger ClO concentrations than have yet been detected.

  19. Phase transformations in sulfuric acid aerosols: Implications for stratospheric ozone depletion

    NASA Astrophysics Data System (ADS)

    Imre, Dan G.; Xu, Jun; Tridico, Anthony C.

    Activation reactions of benign chlorine species (HCl, ClONO2) on aerosols in the winter polar stratosphere set the stage for the spring-time catalytic destruction of ozone leading to the Antarctic ozone hole. Field observations have demonstrated the existence of both solid and liquid particles consisting of H2SO4, HNO3, and H2O. The exact freezing conditions and final composition of the solid aerosols remain the subject of investigations. We present laboratory observations of isolated individual sulfuric acid/water particles under stratospheric temperatures and water vapor pressures. Our experiments demonstrate that this binary system would not freeze unless temperatures were below the water-ice frost point. Upon freezing, we observe H2SO4·8H2O, not the generally invoked H2SO4·4H2O. We suggest that the water-rich octahydrate phase is likely to be one of the high relative humidity forms which is efficient in chlorine activation.

  20. Changes in air quality and tropospheric composition due to depletion of stratospheric ozone and interactions with climate.

    PubMed

    Tang, X; Wilson, S R; Solomon, K R; Shao, M; Madronich, S

    2011-02-01

    , meteorological conditions, and anthropogenic emissions may be large, thus posing challenges for prediction and management of air quality. Aerosols composed of organic substances have a major role in both climate and air quality, and contribute a large uncertainty to the energy budget of the atmosphere. These aerosols are mostly formed via the UV-initiated oxidation of VOCs from anthropogenic and biogenic sources, although the details of the chemistry are still poorly understood and current models under-predict their abundance. A better understanding of their formation, chemical composition, and optical properties is required to assess their significance for air quality and to better quantify their direct and indirect radiative forcing of climate. Emissions of compounds containing fluorine will continue to have effects on the chemistry of the atmosphere and on climate change. The HCFCs and HFCs used as substitutes for ozone-depleting CFCs can break down into trifluoroacetic acid (TFA), which will accumulate in oceans, salt lakes, and playas. Based on historical use and projections of future uses, including new products entering the market, such as the fluoro-olefins, increased loadings of TFA in these environmental sinks will be small. Even when added to existing amounts from natural sources, risks to humans or the environment from the historical use of CFCs or continued use of their replacements is judged to be negligible.

  1. Direct observation of ClO from chlorine nitrate photolysis. [as mechanism of polar ozone depletion

    NASA Technical Reports Server (NTRS)

    Minton, Timothy K.; Nelson, Christine M.; Moore, Teresa A.; Okumura, Mitchio

    1992-01-01

    Chlorine nitrate photolysis has been investigated with the use of a molecular beam technique. Excitation at both 248 and 193 nanometers led to photodissociation by two pathways, ClONO2 yields ClO + NO2 and ClONO2 yields Cl + NO3, with comparable yields. This experiment provides a direct measurement of the ClO product channel and consequently raises the possibility of an analogous channel in ClO dimer photolysis. Photodissociation of the ClO dimer is a critical step in the catalytic cycle that is presumed to dominate polar stratospheric ozone destruction. A substantial yield of ClO would reduce the efficiency of this cycle.

  2. Arctic Ozone Depletion Observed by UARS MLS During the 1994-95 Winter

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Froidevaux, L.; Waters, J. W.; Santee, M. L.; Read, W. G.; Flower, D. A.; Jarnot, R. F.; Zurek, R. W.

    1996-01-01

    During the unusually cold 1994-95 Arctic winter, the Microwave Limb Sounder observed enhanced chlorine monoxide (ClO) in late Dec and throughout Feb and early Mar. Late Dec ClO was higher than during any of the previous 3 years, consistent with the colder early winter. Between late Dec 1994 and early Feb 1995, 465 K (about 50 hPa) vortex-averaged ozone (03) decreased by about 15%, with local decreases of about 30%; additional local decreases of about 5% were seen between early Feb and early Mar. Transport calculations indicate that vortex-averaged chemical loss between late Dec and early Feb was about 20% at 465 K, with about 1/4 of that masked by downward transport of O3. This Arctic chemical O3 loss is not readily detectable in MLS column O3 data.

  3. Spatial variation of ozone depletion rates in the springtime Antarctic polar vortex

    NASA Technical Reports Server (NTRS)

    Yung, Yuk L.; Allen, Mark; Crisp, David; Zurek, Richard W.; Sander, Stanley P.

    1990-01-01

    An area-mapping technique, designed to filter out synoptic perturbations of the Antarctic polar vortex such as distortion or displacement away from the pole, was applied to the Nimbus-7 TOMS (Total Ozone Mapping Spectrometer) data. This procedure reveals the detailed morphology of the temporal evolution of column O3. The results for the austral spring of 1987 suggest the existence of a relatively stable collar region enclosing an interior that is undergoing large variations. A simplified photochemical model of O3 loss and the temporal evolution of the area-mapped polar O3 are used to constrain the chlorine monoxide (ClO) concentrations in the springtime Antarctic vortex. The O3 loss rates could be larger than deduced here because of underestimates of total O3 by TOMS near the terminator.

  4. Arctic Ozone Depletion Observed by UARS MLS During the 1994-95 Winter

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Froidevaux, L.; Waters, J. W.; Santee, M. L.; Read, W. G.; Flower, D. A.; Jarnot, R. F.; Zurek, R. W.

    1996-01-01

    During the unusually cold 1994-95 Arctic winter, the Microwave Limb Sounder observed enhanced chlorine monoxide (ClO) in late Dec and throughout Feb and early Mar. Late Dec ClO was higher than during any of the previous 3 years, consistent with the colder early winter. Between late Dec 1994 and early Feb 1995, 465 K (about 50 hPa) vortex-averaged ozone (03) decreased by about 15%, with local decreases of about 30%; additional local decreases of about 5% were seen between early Feb and early Mar. Transport calculations indicate that vortex-averaged chemical loss between late Dec and early Feb was about 20% at 465 K, with about 1/4 of that masked by downward transport of O3. This Arctic chemical O3 loss is not readily detectable in MLS column O3 data.

  5. More rapid polar ozone depletion through the reaction of HOCl with HCl on polar stratospheric clouds

    NASA Technical Reports Server (NTRS)

    Prather, Michael J.

    1992-01-01

    The direct reaction of HOCl with HCl is shown here to play a critical part in polar ozone loss. Observations of high levels of OClO and ClO in the springtime Antarctic stratosphere confirm that most of the available chlorine is in the form of ClO(x). But current photochemical models have difficulty converting HCl to ClO(x) rapidly enough in early spring to account fully for the observations. Here, a chemical model is used to show that the direct reaction of HOCl with HCl provides the missing mechanism. As alternative sources of nitrogen-containing oxidants have been converted in the late autumn to inactive HNO3 by known reactions on the sulfate layer aerosols, the reaction of HOCl with HCl on polar stratospheric clouds becomes the most important pathway for releasing that stratospheric chlorine which goes into polar night as HCl.

  6. Multimodel Estimates of Atmospheric Lifetimes of Long-lived Ozone-Depleting Substances: Present and Future

    NASA Technical Reports Server (NTRS)

    Chipperfield, M. P.; Liang, Q.; Strahan, S. E.; Morgenstern, O.; Dhomse, S. S.; Abraham, N. L.; Archibald, A. T.; Bekki, S.; Braesicke, P.; Di Genova, G.; Fleming, E. L.; Hardiman, S. C.; Iachetti, D.; Jackman, C. H.; Kinnison, D. E.; Marchand, M.; Pitari, G.; Pyle, J. A.; Rozanov, E.; Stenke, A.; Tummon, F.

    2014-01-01

    We have diagnosed the lifetimes of long-lived source gases emitted at the surface and removed in the stratosphere using six three-dimensional chemistry-climate models and a two-dimensional model. The models all used the same standard photochemical data. We investigate the effect of different definitions of lifetimes, including running the models with both mixing ratio (MBC) and flux (FBC) boundary conditions. Within the same model, the lifetimes diagnosed by different methods agree very well. Using FBCs versus MBCs leads to a different tracer burden as the implied lifetime contained in the MBC value does not necessarily match a model's own calculated lifetime. In general, there are much larger differences in the lifetimes calculated by different models, the main causes of which are variations in the modeled rates of ascent and horizontal mixing in the tropical midlower stratosphere. The model runs have been used to compute instantaneous and steady state lifetimes. For chlorofluorocarbons (CFCs) their atmospheric distribution was far from steady state in their growth phase through to the 1980s, and the diagnosed instantaneous lifetime is accordingly much longer. Following the cessation of emissions, the resulting decay of CFCs is much closer to steady state. For 2100 conditions the model circulation speeds generally increase, but a thicker ozone layer due to recovery and climate change reduces photolysis rates. These effects compensate so the net impact on modeled lifetimes is small. For future assessments of stratospheric ozone, use of FBCs would allow a consistent balance between rate of CFC removal and model circulation rate

  7. Contributions of a Tunable Diode Laser Instrument (ATLAS) to the Stratospheric Ozone Depletion Question

    NASA Technical Reports Server (NTRS)

    Loewenstein, Max; Russell, Philip B. (Technical Monitor)

    1994-01-01

    The Airborne Tunable Laser Absorption Spectrometer - ATLAS - was designed and built at the NASA Ames Research Center and operates on the NASA ER-2 high altitude research aircraft. ATLAS has taken part in a number of important polar and mid-latitude research campaigns, since 1987, focused on various aspects of stratospheric ozone chemistry and dynamics. The chief measurement carried out by the ATLAS second harmonic diode laser spectrometer is of the important atmospheric tracer N2O. Using N2O as an inert tracer we have been able to gain significant new information on polar vortex dynamics and on the correlations of several important long-lived tracers in the stratosphere. The correlation of N2O with NOy (total reactive nitrogen) has been shown to be linear for a great variety of unperturbed stratospheric conditions, and the breakdown of this correlation has been used to detect denitrification by PSCs in the polar vortex, especially in the Antarctic spring. Denitrification is an important step in the process of ozone hole formation in the austral spring. Correlations of N2O with CFCs and CH4 have led to improved estimates of atmospheric lifetimes of these important molecules. Finally the correlation of N2O with CO2, the latter now being measured with great precision by a new instrument on the ER-2, has led to a significant new tool for studying horizontal and vertical mixing in the lower stratosphere, a tool which is very useful in assessing the potential effects of high speed civil transport aircraft in the lower stratosphere. A new, light-weight version of ATLAS is currently being built for unmanned high altitude aircraft, specifically the new Perseus vehicle. We will give a brief description of this effort.

  8. Development of mass production type rigid polyurethane foam for LNG carrier using ozone depletion free blowing agent

    NASA Astrophysics Data System (ADS)

    Lee, Yeongbeom; Baek, Kye Hyun; Choe, Kunhyung; Han, Chonghun

    2016-12-01

    Nowadays the price of natural gas has become higher and the efficiency of propulsion system of liquefied natural gas (LNG) carriers has improved. Due to these trends, required boil-off rate (BOR) for LNG carrier has been lowered from 0.15%/day to 0.12%/day for conventional LNG carriers with sizes between 125,000 m3 and 170,000 m3. This requirement of BOR can be satisfied by using a rigid polyurethane foam (PUF) blown by 1,1-dichloro-1-fluoroethane (HCFC-141b) as an insulator. However, ozone depletion potential (ODP) of HCFC-141b requires alternative blowing agents with zero ODP such as hydroflurocarbons (HFCs) because of tougher environmental regulations. This paper introduces use of HFCs and additives to enhance properties of rigid PUFs under a mass production environment. Among the additives, perfluoroalkane (PFA) reduces thermal conductivity down to 12% and increases compressive strength up to 15% of a rigid PUF prepared in a laboratory scale. Based on this result, a mass production type rigid PUF is manufactured and is evaluated for BOR, mechanical strengths over operation temperature range, and thermal shock stability for LNG carriers. The BOR of the manufactured rigid PUF is below 0.12%/day, which satisfies the recent BOR specification for LNG carriers. The other required properties are also met the specifications for a conventional LNG carrier. Consequently, it is expected that the results in this paper will bring low BOR (<0.12%/day) LNG carries with rigid PUFs using ODP free blowing agents and contribute environmental protection through saving energy and preserving the ozone layer in the stratosphere.

  9. Guarding Embryo Development of Zebrafish by Shell Engineering: A Strategy to Shield Life from Ozone Depletion

    PubMed Central

    Wang, Ben; Liu, Peng; Tang, Yanyan; Pan, Haihua; Xu, Xurong; Tang, Ruikang

    2010-01-01

    Background The reduced concentration of stratospheric ozone results in an increased flux of biologically damaging mid-ultraviolet radiation (UVB, 280 to 320 nm) reaching earth surfaces. Environmentally relevant levels of UVB negatively impact various natural populations of marine organisms, which is ascribed to suppressed embryonic development by increased radiation. Methodology/Principal Findings Inspired by strategies in the living systems generated by evolution, we induce an extra UVB-adsorbed coat on the chorion (eggshell surrounding embryo) of zebrafish, during the blastula period. Short and long UV exposure experiments show that the artificial mineral-shell reduces the UV radiation effectively and the enclosed embryos become more robust. In contrast, the uncoated embryos cannot survive under the enhanced UVB condition. Conclusions We suggest that an engineered shell of functional materials onto biological units can be developed as a strategy to shield lives to counteract negative changes of global environment, or to provide extra protection for the living units in biological research. PMID:20376356

  10. Environmental effects of ozone depletion and its interactions with climate change: progress report, 2011.

    PubMed

    Andrady, Anthony L; Aucamp, Pieter J; Austin, Amy T; Bais, Alkiviadis F; Ballaré, Carlos L; Björn, Lars Olof; Bornman, Janet F; Caldwell, Martyn; Cullen, Anthony P; Erickson, David J; de Gruijl, Frank R; Häder, Donat-P; He, Walter; Ilyas, Mohammad; Longstreth, Janice; Lucas, Robyn; McKenzie, Richard L; Madronich, Sasha; Norval, Mary; Paul, Nigel D; Redhwi, Halim Hamid; Robinson, Sharon; Shao, Min; Solomon, Keith R; Sulzberger, Barbara; Takizawa, Yukio; Tang, Xiaoyan; Torikai, Ayako; van der Leun, Jan C; Williamson, Craig E; Wilson, Stephen R; Worrest, Robert C; Zepp, Richard G

    2012-01-01

    The parties to the Montreal Protocol are informed by three panels of experts. One of these is the Environmental Effects Assessment Panel (EEAP), which deals with two focal issues. The first focus is the effects of increased UV radiation on human health, animals, plants, biogeochemistry, air quality, and materials. The second focus is on interactions between UV radiation and global climate change and how these may affect humans and the environment. When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than believed previously. As a result of this, human health and environmental problems will be longer-lasting and more regionally variable. Like the other panels, the EEAP produces a detailed report every four years; the most recent was published in 2010 (Photochem. Photobiol. Sci., 2011, 10, 173-300). In the years in between, the EEAP produces less detailed and shorter progress reports, which highlight and assess the significance of developments in key areas of importance to the parties. The next full quadrennial report will be published in 2014-2015.

  11. Environmental effects of ozone depletion and its interactions with climate change: progress report, 2009.

    PubMed

    Andrady, Anthony; Aucamp, Pieter J; Bais, Alkiviadis F; Ballaré, Carlos L; Björn, Lars Olof; Bornman, Janet F; Caldwell, Martyn; Cullen, Anthony P; Erickson, David J; deGruijl, Frank R; Häder, Donat-P; Ilyas, Mohammad; Kulandaivelu, G; Kumar, H D; Longstreth, Janice; McKenzie, Richard L; Norval, Mary; Paul, Nigel; Redhwi, Halim Hamid; Smith, Raymond C; Solomon, Keith R; Sulzberger, Barbara; Takizawa, Yukio; Tang, Xiaoyan; Teramura, Alan H; Torikai, Ayako; van der Leun, Jan C; Wilson, Stephen R; Worrest, Robert C; Zepp, Richard G

    2010-03-01

    The parties to the Montreal Protocol are informed by three panels of experts. One of these is the Environmental Effects Assessment Panel (EEAP), which deals with UV radiation and its effects on human health, animals, plants, biogeochemistry, air quality and materials. Since 2000, the analyses and interpretation of these effects have included interactions between UV radiation and global climate change. When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than believed previously. As a result of this, human health and environmental problems will likely be longer-lasting and more regionally variable. Like the other panels, the EEAP produces a detailed report every four years; the most recent was that for 2006 (Photochem. Photobiol. Sci., 2007, 6, 201-332). In the years in between, the EEAP produces a less detailed and shorter progress report, as is the case for this present one for 2009. A full quadrennial report will follow for 2010.

  12. Evidence for Arctic Ozone Depletion in Late February and early March 1994

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Zurek, R. W.; Froidevaux, L.; Waters, J. W.

    1995-01-01

    Significant chemical ozone (O3 ) loss in the 1993-94 Arctic winter occurred mainly during an unusually late cold spell of approximately 10 days in late Feb/early Mar. Over the 30 d period studied (including the cold spell), observed vortex-averaged O3 at 465 K (approximately 40 hPa) decreased by approximately 10%. New three-dimensional, diabatic trajectory calculations show that this observed decrease represents only about half of the net chemical loss (approximately 20%) during the 30 day period. The resupply of lower stratospheric O3 by transport in Feb 1994 was considerably greater than in 1993, when transport masked only about a quarter of the chemical loss in Feb/Mar. The net estimated chemical loss over 30 days in 1994 was comparable to that over the same 30 days in 1993, but mainly occurred at a faster rate during the brief cold spell. These results highlight the impact of Arctic interannual variability on the relative roles of chemistry and dynamics in O3 evolution during recent Arctic winters.

  13. Environmental effects of ozone depletion and its interactions with climate change: Progress report, 2016.

    PubMed

    United Nations Environment Programme Environmental Effects Assessment Panel

    2017-02-15

    The Parties to the Montreal Protocol are informed by three Panels of experts. One of these is the Environmental Effects Assessment Panel (EEAP), which deals with two focal issues. The first focus is the effects of UV radiation on human health, animals, plants, biogeochemistry, air quality, and materials. The second focus is on interactions between UV radiation and global climate change and how these may affect humans and the environment. When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than previously believed. As a result of this, human health and environmental issues will be longer-lasting and more regionally variable. Like the other Panels, the EEAP produces a detailed report every four years; the most recent was published as a series of seven papers in 2015 (Photochem. Photobiol. Sci., 2015, 14, 1-184). In the years in between, the EEAP produces less detailed and shorter Progress Reports of the relevant scientific findings. The most recent of these was for 2015 (Photochem. Photobiol. Sci., 2016, 15, 141-147). The present Progress Report for 2016 assesses some of the highlights and new insights with regard to the interactive nature of the direct and indirect effects of UV radiation, atmospheric processes, and climate change. The more detailed Quadrennial Assessment will be made available in 2018.

  14. Atmospheric lifetimes and Ozone Depletion Potentials of trans-1-chloro-3,3,3-trifluoropropylene and trans-1,2-dichloroethylene in a three-dimensional model

    NASA Astrophysics Data System (ADS)

    Patten, K. O.; Wuebbles, D. J.

    2010-11-01

    The chloroalkenes trans-1-chloro-3,3,3-trifluoropropylene (tCFP) and trans-1,2-dichloroethylene (tDCE) have been proposed as candidate replacements for other compounds in current use that cause concerns regarding potential environmental effects including destruction of stratospheric ozone. Because tCFP and tDCE contain chlorine atoms, the effects of these short-lived compounds on stratospheric ozone must be established. In this study, we derive the atmospheric lifetimes and Ozone Depletion Potentials (ODPs) for tCFP and for tDCE assuming emissions from land surfaces at latitudes 30° N to 60° N using the MOZART 3 three-dimensional model of atmospheric chemistry and physics. 53% of the ozone loss due to tCFP and 98% of the ozone loss due to tDCE take place in the troposphere, rather than in the stratosphere as generally expected from longer-lived chlorocarbons. The atmospheric lifetime of tCFP against chemical reaction is 40.4 days, and its ODP is quite small at 0.00034. The tDCE atmospheric lifetime is 12.7 days, and its ODP is 0.00024, which is the lowest ODP found for any chlorocarbon we have studied. Our study suggests that chlorine from tCFP and tDCE are unlikely to affect ozone at quantities likely to be emitted to the atmosphere.

  15. Link Winds: A visual data analysis system and its application to the atmospheric ozone depletion problem

    NASA Technical Reports Server (NTRS)

    Jacobson, Allan S.; Berkin, Andrew L.

    1995-01-01

    The Linked Windows Interactive Data System (LinkWinds) is a prototype visual data exploration system resulting from a NASA Jet Propulsion Laboratory (JPL) program of research into the application of graphical methods for rapidly accessing, displaying, and analyzing large multi variate multidisciplinary data sets. Running under UNIX it is an integrated multi-application executing environment using a data-linking paradigm to dynamically interconnect and control multiple windows containing a variety of displays and manipulators. This paradigm, resulting in a system similar to a graphical spreadsheet, is not only a powerful method for organizing large amounts of data for analysis, but leads to a highly intuitive, easy-to-learn user interface. It provides great flexibility in rapidly interacting with large masses of complex data to detect trends, correlations, and anomalies. The system, containing an expanding suite of non-domain-specific applications, provides for the ingestion of a variety of data base formats and hard -copy output of all displays. Remote networked workstations running LinkWinds may be interconnected, providing a multiuser science environment (MUSE) for collaborative data exploration by a distributed science team. The system is being developed in close collaboration with investigators in a variety of science disciplines using both archived and real-time data. It is currently being used to support the Microwave Limb Sounder (MLS) in orbit aboard the Upper Atmosphere Research Satellite (UARS). This paper describes the application of LinkWinds to this data to rapidly detect features, such as the ozone hole configuration, and to analyze correlations between chemical constituents of the atmosphere.

  16. Link Winds: A visual data analysis system and its application to the atmospheric ozone depletion problem

    NASA Technical Reports Server (NTRS)

    Jacobson, Allan S.; Berkin, Andrew L.

    1995-01-01

    The Linked Windows Interactive Data System (LinkWinds) is a prototype visual data exploration system resulting from a NASA Jet Propulsion Laboratory (JPL) program of research into the application of graphical methods for rapidly accessing, displaying, and analyzing large multi variate multidisciplinary data sets. Running under UNIX it is an integrated multi-application executing environment using a data-linking paradigm to dynamically interconnect and control multiple windows containing a variety of displays and manipulators. This paradigm, resulting in a system similar to a graphical spreadsheet, is not only a powerful method for organizing large amounts of data for analysis, but leads to a highly intuitive, easy-to-learn user interface. It provides great flexibility in rapidly interacting with large masses of complex data to detect trends, correlations, and anomalies. The system, containing an expanding suite of non-domain-specific applications, provides for the ingestion of a variety of data base formats and hard -copy output of all displays. Remote networked workstations running LinkWinds may be interconnected, providing a multiuser science environment (MUSE) for collaborative data exploration by a distributed science team. The system is being developed in close collaboration with investigators in a variety of science disciplines using both archived and real-time data. It is currently being used to support the Microwave Limb Sounder (MLS) in orbit aboard the Upper Atmosphere Research Satellite (UARS). This paper describes the application of LinkWinds to this data to rapidly detect features, such as the ozone hole configuration, and to analyze correlations between chemical constituents of the atmosphere.

  17. Possible impacts of ozone depletion on trophic interactions and biogenic vertical carbon flux in the Southern Ocean

    SciTech Connect

    Marchant, H.J.; Davidson, A.

    1992-03-01

    Among the most productive region of the Southern Ocean is the marginal ice edge zone that trails the retreating ice edge in spring and early summer. The timing of this near-surface phytoplankton bloom coincides with seasonal stratospheric ozone depletion when UV irradiance is reportedly as high as in mid-summer. Recent investigations indicate that antarctic marine phytoplankton are presently UV stressed. The extent to which increasing UV radiation diminishes the ability of phytoplankton to fix C02 and/or leads to changes in their species composition is equivocal. The colonial stage in the life cycle of the alga Phaeocystis pouchetii is one of the major components of the bloom. The authors have found that this alga produces extracellular products which are strongly UV-B absorbing. When exposed to increasing levels of UV-B radiation, survival of antarctic colonial Phaeocystis was significantly greater than colonies of this species from temperate waters and of the single-celled stage of its life cycle which produces no UV-B-absorbing compounds. Phaeocystis is apparently a minor dietary component of Antarctic krill, Euphausia superba, and its nutritional value to crustacea is reportedly low. Phytoplankton, principally diatoms, together with fecal pellets and molted exoskeletons of grazers contribute most of the particulate carbon flux from the euphotic zone to deep water.

  18. The municipal solid waste landfill as a source of ozone-depleting substances in the United States and United Kingdom

    NASA Astrophysics Data System (ADS)

    Hodson, E. L.; Martin, D.; Prinn, R. G.

    2010-02-01

    This study provides observation-based national estimates of CFC-11, CFC-12, CFC-113, and 1,1,1-trichloroethane emissions for the United States (US) and United Kingdom (UK) from municipal solid waste (MSW) landfills. The scarcity of national estimates has lead to the assumption that a significant fraction of the lingering ozone-depleting substance (ODS) emissions, which have been detected in industrialized countries, could be emitted from landfills. Spatial coverage was achieved through sampling at seven landfills in Massachusetts and through data provided by nine UK landfills. Linear least square regressions of recovered ODS vs. CH4 were used in combination with national estimates of landfill CH4 emissions to estimate 2006 national US and UK ODS landfill emissions. The ODS landfill emission estimates were then compared to recent estimates of total US and UK ODS emissions. US ODS landfill emissions are 0.4%-1% (0.006-0.09 Gg/year) of total US emissions. UK ODS landfill emission estimates are 1% (0.008 Gg/year) and 6% (0.03 Gg/year) of total UK CFC-11 and CFC-12 emissions, respectively. This indicates that landfills are only a minor source of lingering ODS emissions in the US, but may be more significant for CFC-12 emissions in the UK. The implication is that the majority of current ODS emissions in industrialized countries is likely coming from equipment still in use.

  19. The municipal solid waste landfill as a source of ozone-depleting substances in the United States and United Kingdom

    NASA Astrophysics Data System (ADS)

    Hodson, E. L.; Martin, D.; Prinn, R. G.

    2009-10-01

    This study provides observation-based national estimates of CFC-11, CFC-12, CFC-113, and 1,1,1-trichloroethane emissions for the United States (US) and United Kingdom (UK) from municipal solid waste (MSW) landfills. The scarcity of national estimates has lead to the assumption that a significant fraction of the lingering ozone-depleting substance (ODS) emissions, which have been detected in industrialized countries, could be emitted from landfills. Spatial coverage was achieved through sampling at seven landfills in Massachusetts and through data provided by nine UK landfills. Linear least square regressions of recovered ODS vs. CH4 were used in combination with national estimates of landfill CH4 emissions to estimate 2006 national US and UK ODS landfill emissions. The ODS landfill emission estimates were then compared to recent estimates of total US and UK ODS emissions. US ODS landfill emissions were 0.4%-0.9% (0.006-0.09 Gg/year) of total US emissions. UK ODS landfill emission estimates were 1% (0.008 Gg/year) and 6% (0.03 Gg/year) of total UK CFC-11 and CFC-12 emissions, respectively. This indicates that landfills are only a minor source of lingering ODS emissions in the US, but may be more significant for CFC-12 emissions in the UK. The implications are that the majority of current ODS emissions in industrialized countries are likely coming from equipment still in use.

  20. Evaluation of no-clean solder process designed to eliminate the use of ozone-depleting chemicals

    SciTech Connect

    Paffett, M.T.; Farr, J.D.; Rogers, Y.C.; Hutchinson, W.B.

    1993-10-01

    This paper summarizes the LANL contributions to a joint Motorola/SNLA/LANL cooperative research and development agreement study on the reliability of an alternative solder process that is intended to reduce or eliminate the use of ozone-depleting chemicals in the manufacture of printed wire boards (PWBs). This process is termed self-cleaning because of the nature of the thermal chemistry associated with the adipic and formic acid components used in place of traditional solder rosin fluxes. Traditional rosin fluxes used in military electronic hardware applications are cleaned (by requirement) using chlorofluorohydrocarbons. The LANL contribution centers around analytical determination of PWB cleanliness after soldering using the self-cleaning method. Results of these analytical determinations involving primarily surface analysis of boards following temperature, temperature and humidity, and long-term storage testing are described with representative data. It is concluded that the self-cleaning process leaves behind levels of solid residue that are visually and analytically observable using most of these surface analysis techniques. The materials compatibility of electronic components soldered using the self-cleaning soldering process is more fully described in the project report issued by SNLA that encompasses the complete project with statistical lifetime and accelerated aging studies. Analytical surface specificity and suggestions for further work are also given.

  1. Model of risk of cortical cataract in the US population with exposure to increased ultraviolet radiation due to stratospheric ozone depletion.

    PubMed

    West, Sheila K; Longstreth, Janice D; Munoz, Beatriz E; Pitcher, Hugh M; Duncan, Donald D

    2005-12-01

    The authors modeled the possible consequences for US cataract incidence of increases in ultraviolet B radiation due to ozone depletion. Data on the dose-response relation between ocular exposure to ultraviolet B radiation and cortical cataract were derived from a population-based study (the Salisbury Eye Evaluation Project, Salisbury, Maryland) in which extensive data on cataract and ultraviolet radiation were collected in persons aged 65-84 years. Exposure estimates for the US population were derived using estimated ultraviolet radiation fluxes as a function of wavelength. US Census data were used to obtain the age, ethnicity, and sex distribution of the population. Predicted probabilities of cataract were derived from the age-, sex-, and ethnicity-specific ocular ultraviolet exposure data and were modeled under conditions of 5-20% ozone depletion. The analysis indicated that by 2050, the prevalence of cortical cataract will increase above expected levels by 1.3-6.9%. The authors estimate that with 5-20% ozone depletion, there will be 167,000-830,000 additional cases of cortical cataract by 2050. Because of the high prevalence of cataract in older persons, at a 2003 cost of 3,370 dollars per cataract operation, this increase could represent an excess cost of 563 million dollars to 2.8 billion dollars.

  2. Basic Ozone Layer Science

    EPA Pesticide Factsheets

    Learn about the ozone layer and how human activities deplete it. This page provides information on the chemical processes that lead to ozone layer depletion, and scientists' efforts to understand them.

  3. Atmospheric lifetimes and ozone depletion potentials of trans-1-chloro-3,3,3-trifluoropropylene and trans-1,2-dichloroethylene in a three-dimensional model

    NASA Astrophysics Data System (ADS)

    Patten, K. O.; Wuebbles, D. J.

    2010-07-01

    The chloroalkenes trans-1-chloro-3,3,3-trifluoropropylene (tCFP) and trans-1,2-dichloroethylene (tDCE) have been proposed as candidate replacements for other compounds in current use that cause concerns regarding potential environmental effects including destruction of stratospheric ozone. Because tCFP and tDCE contain chlorine atoms, the effects of these short-lived compounds on stratospheric ozone must be established. In this study, we derive the atmospheric lifetimes and Ozone Depletion Potentials (ODPs) for tCFP and for tDCE assuming emissions from land surfaces at latitudes 30° N to 60° N using the MOZART 3 three-dimensional model of atmospheric chemistry and physics. Both tCFP and tDCE are shown to primarily affect ozone in the troposphere, rather than in the stratosphere as generally expected from longer-lived chlorocarbons. The atmospheric lifetime of tCFP against chemical reaction is 40.4 days, and its ODP is quite small at 0.00034. The tDCE atmospheric lifetime is 12.7 days, and its ODP is 0.00024, which is the lowest ODP found for any chlorocarbon we have studied. Our study suggests that chlorine from tCFP and tDCE are unlikely to significantly affect ozone at quantities likely to be emitted to the atmosphere.

  4. Understanding Tropospheric Ozone Variability in the Arctic

    NASA Astrophysics Data System (ADS)

    McClure-Begley, A.; Petropavlovskikh, I. V.; Crepinsek, S.; Uttal, T.; Skov, H.

    2016-12-01

    The Arctic is a region that has been subject to drastic changes in the climate partially due to transported pollutants which strongly impact the composition of the atmosphere and associated feedbacks. Tropospheric ozone is an atmospheric species formed by the reaction of precursor species (NOx, CO, VOC's) in the presence of UV radiation and drives complex interactions which can result in impacts on atmospheric conditions in the Arctic. As an important greenhouse gas, ozone has a significant influence on the photochemical characteristics, oxidation capacity, and radiative forcing of the atmosphere and at high levels has negative impacts on public health and overall ecosystem functioning. In the Arctic, tropospheric ozone has variable characteristics in time and space. Seasonal variation of ozone is controlled by many factors influencing the production and destruction of ozone. The arctic ozone conditions are strongly influenced by seasonal destruction events, arctic haze, transport of pollution from Asia and influence from precursor compounds released from wildfires. This study investigates long-term ozone variation, seasonal surface ozone conditions, and characterizes deviations from expected ozone levels at four arctic ozone measurement locations (Barrow Alaska, Tiksi Russia, Summit Greenland, and Villum Station Greenland). Frequency of ozone depletion events and high ozone episodes for each station over time provides a context for the changing conditions of ozone in the arctic. NOAA Hysplit back-trajectory analysis, satellite imagery, NOAA Smoke verification model, co-located carbon monoxide, carbon dioxide, and aerosol optical depth measurements are used to understand the dominant source of pollution, pollutant composition, and the interactions due to meteorological conditions that result in anomalies in the ozone mixing ratio records. Characterization of ozone behavior and influences on the measurement locations is essential for understanding the spatial and

  5. Effect of solar ultraviolet-B radiation during springtime ozone depletion on photosynthesis and biomass production of Antarctic vascular plants.

    PubMed

    Xiong, F S; Day, T A

    2001-02-01

    We assessed the influence of springtime solar UV-B radiation that was naturally enhanced during several days due to ozone depletion on biomass production and photosynthesis of vascular plants along the Antarctic Peninsula. Naturally growing plants of Colobanthus quitensis (Kunth) Bartl. and Deschampsia antarctica Desv. were potted and grown under filters that absorbed or transmitted most solar UV-B. Plants exposed to solar UV-B from mid-October to early January produced 11% to 22% less total, as well as above ground biomass, and 24% to 31% less total leaf area. These growth reductions did not appear to be associated with reductions in photosynthesis per se: Although rates of photosynthetic O(2) evolution were reduced on a chlorophyll and a dry-mass basis, on a leaf area basis they were not affected by UV-B exposure. Leaves on plants exposed to UV-B were denser, probably thicker, and had higher concentrations of photosynthetic and UV-B absorbing pigments. We suspect that the development of thicker leaves containing more photosynthetic and screening pigments allowed these plants to maintain their photosynthetic rates per unit leaf area. Exposure to UV-B led to reductions in quantum yield of photosystem II, based on fluorescence measurements of adaxial leaf surfaces, and we suspect that UV-B impaired photosynthesis in the upper mesophyll of leaves. Because the ratio of variable to maximal fluorescence, as well as the initial slope of the photosynthetic light response, were unaffected by UV-B exposure, we suggest that impairments in photosynthesis in the upper mesophyll were associated with light-independent enzymatic, rather than photosystem II, limitations.

  6. The influence of ozone forcing on blocking in the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Dennison, Fraser; McDonald, Adrian; Morgenstern, Olaf

    2016-04-01

    We investigate the influence of ozone depletion and recovery on blocking in the Southern Hemisphere. Blocking events are identified using a persistent positive anomaly method applied to 500hPa geopotential height. Using the NIWA-UKCA chemistry-climate model, we compare reference runs including forcing due to greenhouse gases and ozone depleting substances to sensitivity simulations in which ozone depleting substances are fixed at their 1960 abundances and other sensitivity simulations with greenhouse gases fixed at their 1960 abundances. We find that during summer ozone depletion leads to an increased frequency of blocking in the South Atlantic while having little effect in the South Pacific. Blocking events in the South Atlantic are shown to follow positive anomalies in the stratospheric Southern Annular Mode (SAM) index; this is not the case for South Pacific blocking events. This difference would seem to explain the change in blocking frequency as during summer, in the model and in reality ozone depletion pushes the SAM towards its positive polarity. Similarly, ozone recovery, having the opposite influence on the SAM, leads to a reduction in blocking frequency in the South Atlantic, although this is somewhat counteracted by the effect of increasing greenhouse gases

  7. Cloud Acidity and Acidic Deposition in the Lower Troposphere and Ozone Depletion in the Antarctic Stratosphere: Modeling and Data Analysis Regarding the Role of Atmospheric Aerosol.

    NASA Astrophysics Data System (ADS)

    Lin, Neng-Huei

    This study is focused on the role of atmospheric aerosols in determining the cloud acidity and acidic deposition in the lower troposphere and the ozone depletion in the Antarctic stratosphere. For the former, a cloud chemistry model is developed to study the in-cloud chemistry and acidity in cloud droplets. The cloud chemistry model includes the absorption of trace gases, the oxidation of aqueous phase SO_2, and the scavenging of atmospheric aerosols. A new scheme is developed to differentiate the acidity and chemical composition distributing in individual cloud droplets. The above cloud chemistry model is incorporated into a two-layer flow model in order to investigate the effects of mountain waves on the cloud acidity. Using the three-year (1986-1988) database acquired at Mt. Mitchell site, the in-cloud chemistry and acidic deposition through dry, wet and cloud deposition pathways are investigated. The in-cloud scavenging of submicron aerosols such as sulfates and nitrates is parameterized as a function of cloud deposition rate. The deposition fluxes of sulfur (S) compounds are found primarily contributed by cloud capture mechanism (60%) followed by incident precipitation (25%) and dry deposition (15%). A comparison of deposition estimates at Mt. Mitchell with those at other sites shows that the sulfate deposition at sites exceeding 1,200 m MSL in elevation in Bavaria (Germany) and eastern USA is almost identical within error limits. The features of the Antarctic stratospheric aerosols during the ozone depletion episode of October 1987 are investigated based on the SAGE II (Stratospheric Aerosol and Gas Experiment II) data. The study focuses on (1) inferring the aerosol size spectrum using a modified randomized minimization-search-technique (RMST), and (2) investigating the vertical, zonal and columnar averages of aerosol properties, together with the ozone concentration. The aerosol size distribution is found to be bimodal in several instances. An enhanced

  8. Depletion of stratospheric ozone over the Antarctic and Arctic: responses of plants of polar terrestrial ecosystems to enhanced UV-B, an overview.

    PubMed

    Rozema, Jelte; Boelen, Peter; Blokker, Peter

    2005-10-01

    Depletion of stratospheric ozone over the Antarctic has been re-occurring yearly since 1974, leading to enhanced UV-B radiation. Arctic ozone depletion has been observed since 1990. Ozone recovery has been predicted by 2050, but no signs of recovery occur. Here we review responses of polar plants to experimentally varied UV-B through supplementation or exclusion. In supplementation studies comparing ambient and above ambient UV-B, no effect on growth occurred. UV-B-induced DNA damage, as measured in polar bryophytes, is repaired overnight by photoreactivation. With UV exclusion, growth at near ambient may be less than at below ambient UV-B levels, which relates to the UV response curve of polar plants. UV-B screening foils also alter PAR, humidity, and temperature and interactions of UV with environmental factors may occur. Plant phenolics induced by solar UV-B, as in pollen, spores and lignin, may serve as a climate proxy for past UV. Since the Antarctic and Arctic terrestrial ecosystems differ essentially, (e.g. higher species diversity and more trophic interactions in the Arctic), generalization of polar plant responses to UV-B needs caution.

  9. Uncertainty propagation in a stratospheric model. I - Development of a concise stratospheric model. II - Monte Carlo analysis of imprecisions due to reaction rates. [for ozone depletion prediction

    NASA Technical Reports Server (NTRS)

    Rundel, R. D.; Butler, D. M.; Stolarski, R. S.

    1978-01-01

    The paper discusses the development of a concise stratospheric model which uses iteration to obtain coupling between interacting species. The one-dimensional, steady-state, diurnally-averaged model generates diffusion equations with appropriate sources and sinks for species odd oxygen, H2O, H2, CO, N2O, odd nitrogen, CH4, CH3Cl, CCl4, CF2Cl2, CFCl3, and odd chlorine. The model evaluates steady-state perturbations caused by injections of chlorine and NO(x) and may be used to predict ozone depletion. The model is used in a Monte Carlo study of the propagation of reaction-rate imprecisions by calculating an ozone perturbation caused by the addition of chlorine. Since the model is sensitive to only 10 of the more than 50 reaction rates considered, only about 1000 Monte Carlo cases are required to span the space of possible results.

  10. Temporal trends and spatial variations of ozone-depleting substances (ODS) in the Pearl River Delta (PRD) region, southern China

    NASA Astrophysics Data System (ADS)

    Zhang, Yanli; Wang, Xinming; Blake, Donald; Simpson, Isobel

    2014-05-01

    Long-term observation of mixing ratios of ozone-depleting substances (ODS) in ambient air can help to assess the implementation of the Montreal Protocol and Its Amendments in regional and national scales. Here we present our measurement of ODS such as CFCs, HCFCs, halons and other halocarbons in ambient air since 2000 in the Pearl River Delta (PRD) region, one of the most densely populated and highly industrialized regions that was supposed to be a hotspot for ODS emission in China. These halocarbons in the PRD region were found to have 5-348% enhancements when compared to their global background levels. CFC-12 and CFC-11 in the region, for example, were 37-56% and 12-43%, respectively, above their global background levels. CFC replacement compounds showed even larger enhancements. In average mixing ratios of HCFC-22, HCFC-141b, and HCFC-142b were 89%, 87%, and 86% above their background levels of 148 ppt, 12.1 ppt, and 12.1 ppt in the year of 2000, respectively; and 72%, 125%, and 52% over their background levels of 205 ppt, 20.2 ppt, and 20.0 ppt in the year of 2009, respectively. During 2000-2009, CFCs in the PRD region showed decline trends with the decreasing rates of -3.0, -5.9, and -9.4 ppt/yr for CFC-12, CFC-11, and CFC-113, respectively; these rates were faster than that at the global background sites, which were -0.91, -2.12, and -0.69 ppt/yr, respectively. The CFCs substitutes HCFC-22, HCFC-141b, and HCFC-142b, however, showed increasing trends with the increasing rates of 8.0, 2.6, and 0.9 ppt/yr, respectively. HFC-134a, a refrigerant used for mobile air conditioning, showed rapid increase with a rate of 15 ppt/yr from 2000 to 2009 in the region. As for other halocarbons, methyl chloroform and carbon tetrachloride decreased with rates of 21 and 1 ppt/yr during the period. The mixing ratios of methyl chloride in the region showed unusual rapid increase at a rate of 64 ppt/yr when compared to its increasing rate of 1.3 ppt/yr at the global background

  11. Analysis of the eight-year trend in ozone depletion from empirical models of solar backscattered ultraviolet instrument degradation

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Hudson, R. D.; Serafino, G.

    1990-01-01

    Arguments are presented showing that the basic empirical model of the solar backscatter UV (SBUV) instrument degradation used by Cebula et al. (1988) in their analysis of the SBUV data is likely to lead to an incorrect estimate of the ozone trend. A correction factor is given as a function of time and altitude that brings the SBUV data into approximate agreement with the SAGE, SME, and Dobson network ozone trends. It is suggested that the currently archived SBUV ozone data should be used with caution for periods of analysis exceeding 1 yr, since it is likely that the yearly decreases contained in the archived data are too large.

  12. Tropospheric ozone surface depletion (spring) and pollution (summer) in 2008 from the ARCTAS Intensive Ozonesonde Network Study (ARC-IONS) soundings

    NASA Astrophysics Data System (ADS)

    Thompson, A. M.; Luzik, A. M.; Doughty, D. C.; Gallagher, S. D.; Miller, S. K.; Oltmans, S. J.; Tarasick, D. W.; Witte, J. C.; Bryan, A. M.; Walker, T.; Osterman, G. B.; Worden, J.

    2008-12-01

    During NASA's ARCTAS (Arctic Research of the Composition of the Troposphere with Aircraft and Satellites; http://espo.nasa.gov/arctas) spring and summer 2008 campaigns, an ozonesonde network, ARC- IONS (ARCTAS Intensive Ozonesonde Network Study), launched ozonesonde-radiosonde packages each day (1-20 April, 26 June-12 July) during the A-Train satellite constellation overpass, ~1300 local. Seventeen ARC-IONS stations were located across the northern tier of North America, over both Alaska and Canada, with one site in Greenland and two in the western US; map at (http://croc.gsfc.nasa.gov/arcions). In addition to satellite validation, the soundings provided a coherent, well-distributed set of ozone profiles for: (1) comparison with and interpretation of airborne measurements; (2) complementarity to ARCTAS and IPY (International Polar Year) ground bases at Greenland, Barrow, Eureka, Yellowknife; (3) model evaluation; (4) investigations of processes affecting day-to-day ozone variability. Two aspects of tropospheric ozone variability are described here. First, ozone depletion likely associated with rapid halogen reactions, is prominent in spring at Barrow (71N, 157W) and Resolute (75N, 95W). Second, during summer, relationships among long-range transport of Asian pollution (industrial and fires), California and Canadian fires and daily ozone budgets are established with trajectories, satellite smoke/fire data and laminar identification, the latter method developed in Thompson et al. (2007) and Yorks et al. (2008). Canadian maritime stations display eastern seaboard pollution and stratospheric influences as in IONS-04 (INTEX Ozonesonde Network Study).

  13. Mitigation of 21st century Antarctic sea ice loss by stratospheric ozone recovery

    NASA Astrophysics Data System (ADS)

    Smith, Karen L.; Polvani, Lorenzo M.; Marsh, Daniel R.

    2012-10-01

    We investigate the effect of stratospheric ozone recovery on Antarctic sea ice in the next half-century, by comparing two ensembles of integrations of the Whole Atmosphere Community Climate Model, from 2001 to 2065. One ensemble is performed by specifying all forcings as per the Representative Concentration Pathway 4.5; the second ensemble is identical in all respects, except for the surface concentrations of ozone depleting substances, which are held fixed at year 2000 levels, thus preventing stratospheric ozone recovery. Sea ice extent declines in both ensembles, as a consequence of increasing greenhouse gas concentrations. However, we find that sea ice loss is ∼33% greater for the ensemble in which stratospheric ozone recovery does not take place, and that this effect is statistically significant. Our results, which confirm a previous study dealing with ozone depletion, suggest that ozone recovery will substantially mitigate Antarctic sea ice loss in the coming decades.

  14. Analysis of the eight-year trend in ozone depletion from empirical models of solar backscattered ultraviolet instrument degradation

    SciTech Connect

    Herman, J.R.; Hudson, R.D. ); Serafino, G. )

    1990-05-20

    Currently archived ozone data from the Solar Backscatter Ultraviolet (SBUV) spectrometer experiment on the Nimbus 7 satellite has been reported to show large global decreases in the amount of atmospheric ozone, both total content and as a function of altitude, for the period from 1978 to 1987. Analysis of atmospheric albedo data leading to these reported trends was based on empirical models of the SUBV spectrometer and diffuser plate degradation with time. The central problem in analyzing SBUV data is to separately specify the diffuser plate degradation. Ratios of radiance to solar irradiance used to obtain ozone amounts are proportional only to diffuser reflectivity and independent of any spectrometer degradation. A new class of explicitly empirical models have been developed that produce a better fit to all of the SUBV solar flux data. The models have a single free parameter to separately specify the diffuser plate and spectrometer degradation. This parameter must be within a narrow range to bring the calculated ozone trend into approximate agreement with data from the Dobson network, Solar Mesospheric Explorer (SME) and Stratospheric Aerosol Gas Experiment (SAGE) satellites, or with the different trends reported from the Umkehr ground stations. It is shown that outside sources of ozone data must be used to obtain a unique solution from SBUV radiance data within the precision necessary to determine the existence of a global annual ozone decrease. A correction factor is given as a function of time and altitude that brings the SBUV data into approximate agreement with SAGE, SME, and Dobson ozone trends. The currently archived SBUV ozone data should be used with caution for periods of analysis exceeding 1 year, since it is likely that the yearly decreases contained in the archived data are too large.

  15. The Antarctic ozone hole

    NASA Astrophysics Data System (ADS)

    Molina, Mario J.

    Observations of Antarctic ozone levels and the discovery of a hole in the Antarctic region are examined. The effects of chlorofluorocarbons (CFCs) on the level of stratospheric ozone are analyzed. Three cycles explaining the cause of ozone depletion in the poles are proposed. A comparison of field data and proposed depletion cycles reveals that the chemical origin of the ozone hole is due to CFCs. The potential global effects of the Antarctic ozone hole are discussed.

  16. Plant responses to current solar ultraviolet-B radiation and to supplemented solar ultraviolet-B radiation simulating ozone depletion: an experimental comparison.

    PubMed

    Rousseaux, M Cecilia; Flint, Stephan D; Searles, Peter S; Caldwell, Martyn M

    2004-01-01

    Field experiments assessing UV-B effects on plants have been conducted using two contrasting techniques: supplementation of solar UV-B with radiation from fluorescent UV lamps and the exclusion of solar UV-B with filters. We compared these two approaches by growing lettuce and oat simultaneously under three conditions: UV-B exclusion, near-ambient UV-B (control) and UV-B supplementation (simulating a 30% ozone depletion). This permitted computation of "solar UV-B" and "supplemental UV-B" effects. Microclimate and photosynthetically active radiation were the same under the two treatments and the control. Excluding UV-B changed total UV-B radiation more than did supplementing UV-B, but the UV-B supplementation contained more "biologically effective" shortwave radiation. For oat, solar UV-B had a greater effect than supplemental UV-B on main shoot leaf area and main shoot mass, but supplemental UV-B had a greater effect on leaf and tiller number and UV-B-absorbing compounds. For lettuce, growth and stomatal density generally responded similarly to both solar UV-B and supplemented UV-B radiation, but UV-absorbing compounds responded more to supplemental UV-B, as in oat. Because of the marked spectral differences between the techniques, experiments using UV-B exclusion are most suited to assessing effects of present-day UV-B radiation, whereas UV-B supplementation experiments are most appropriate for addressing the ozone depletion issue.

  17. Twenty Five Years of Airborne Observations of Ozone-Depleting and Climate-Related Gases in the Upper Troposphere and Lower Stratosphere.

    NASA Astrophysics Data System (ADS)

    Elkins, J. W.; Moore, F. L.; Hintsa, E. J.; Dutton, G. S.; Nance, J. D.; Hall, B. D.

    2016-12-01

    NOAA scientists started in situ airborne measurements of two strong ozone-depleting gases or chlorofluorocarbons, CFC-11 and CFC-113 in 1991 on the NASA ER-2 aircraft with a two-channel gas chromatograph, Airborne Chromatograph for Atmospheric Trace Species (ACATS). We broaden our list of gases to include more ozone-depleting and other climate-related gases. An improved 4-channel gas chromatograph that included N2O, SF6, CFC-11, -12, -113, halon-1211, CCl4, CH3CCl3, CH4, CO, and H2 was added to the ER-2 aircraft in 1994. As CFC replacements took hold, we add a gas chromatograph-mass spectrometer system, PAN and other Trace Hydro-halocarbon Experiment (PANTHER), to examine shorter-lived gases mainly in the upper troposphere. These airborne measurements were to complement of ground-based flask and in situ measurements from the NOAA Halocarbon and other Trace Species Network. This talk will show results from a tropical study, Airborne Tropical Tropopause Experiment (ATTREX) on the NASA Global Hawk aircraft and preliminary results from the Atmospheric Tomography Mission (ATom) conducted in August 2016 on the NASA DC-8 aircraft. A detrended, gridded, latitudinal distribution of SF6 is shown in the figure below for the years of 1994 through 2014. Such a plot may be useful to atmospheric modelers trying to capture transport or calculate emissions.

  18. The influence of ultraviolet-B radiation on growth, hydroxycinnamic acids and flavonoids of Deschampsia antarctica during Springtime ozone depletion in Antarctica.

    PubMed

    Ruhland, Christopher T; Xiong, Fusheng S; Clark, W Dennis; Day, Thomas A

    2005-01-01

    We examined the influence of solar ultraviolet-B radiation (UV-B; 280-320 nm) on the growth, biomass production and phenylpropanoid concentrations of Deschampsia antarctica during the springtime ozone depletion season at Palmer Station, along the Antarctic Peninsula. Treatments involved placing filters on frames over potted plants that reduced levels of biologically effective UV-B either by 83% (reduced UV-B) or by 12% (near-ambient UV-B) over the 63 day experiment (7 November 1998-8 January 1999) when ozone depletion averaged 17%. Plants growing under near-ambient UV-B had 41% and 40% lower relative growth rates and net assimilation rates, respectively, than those under reduced UV-B. The former plants produced 50% less total biomass as a result of having 47% less aboveground biomass. The reduction in aboveground biomass was a result of a 29% lower leaf elongation rate resulting in shorter leaves and 59% less total leaf area in plants grown under reduced UV-B. p-Coumaric, caffeic and ferulic acids were the major hydroxycinnamic acids, and luteolin derivatives were the major flavonoids in both insoluble and soluble leaf extracts. Concentrations of insoluble p-coumaric and caffeic acid and soluble ferulic acids were 38%, 48% and 60% higher, respectively, under near-ambient UV-B than under reduced UV-B. There were no UV-B effects on concentrations of insoluble or soluble flavonoids.

  19. Derivation of the reduced reaction mechanisms of ozone depletion events in the Arctic spring by using concentration sensitivity analysis and principal component analysis

    NASA Astrophysics Data System (ADS)

    Cao, Le; Wang, Chenggang; Mao, Mao; Grosshans, Holger; Cao, Nianwen

    2016-12-01

    The ozone depletion events (ODEs) in the springtime Arctic have been investigated since the 1980s. It is found that the depletion of ozone is highly associated with an auto-catalytic reaction cycle, which involves mostly the bromine-containing compounds. Moreover, bromide stored in various substrates in the Arctic such as the underlying surface covered by ice and snow can be also activated by the absorbed HOBr. Subsequently, this leads to an explosive increase of the bromine amount in the troposphere, which is called the "bromine explosion mechanism". In the present study, a reaction scheme representing the chemistry of ozone depletion and halogen release is processed with two different mechanism reduction approaches, namely, the concentration sensitivity analysis and the principal component analysis. In the concentration sensitivity analysis, the interdependence of the mixing ratios of ozone and principal bromine species on the rate of each reaction in the ODE mechanism is identified. Furthermore, the most influential reactions in different time periods of ODEs are also revealed. By removing 11 reactions with the maximum absolute values of sensitivities lower than 10 %, a reduced reaction mechanism of ODEs is derived. The onsets of each time period of ODEs in simulations using the original reaction mechanism and the reduced reaction mechanism are identical while the maximum deviation of the mixing ratio of principal bromine species between different mechanisms is found to be less than 1 %. By performing the principal component analysis on an array of the sensitivity matrices, the dependence of a particular species concentration on a combination of the reaction rates in the mechanism is revealed. Redundant reactions are indicated by principal components corresponding to small eigenvalues and insignificant elements in principal components with large eigenvalues. Through this investigation, aside from the 11 reactions identified as unimportant in the concentration

  20. Non-CO2 greenhouse gases and climate change.

    PubMed

    Montzka, S A; Dlugokencky, E J; Butler, J H

    2011-08-03

    Earth's climate is warming as a result of anthropogenic emissions of greenhouse gases, particularly carbon dioxide (CO(2)) from fossil fuel combustion. Anthropogenic emissions of non-CO(2) greenhouse gases, such as methane, nitrous oxide and ozone-depleting substances (largely from sources other than fossil fuels), also contribute significantly to warming. Some non-CO(2) greenhouse gases have much shorter lifetimes than CO(2), so reducing their emissions offers an additional opportunity to lessen future climate change. Although it is clear that sustainably reducing the warming influence of greenhouse gases will be possible only with substantial cuts in emissions of CO(2), reducing non-CO(2) greenhouse gas emissions would be a relatively quick way of contributing to this goal.

  1. Observation of NO(x) Enhancement and Ozone Depletion in the Northern and Southern hemispheres after the October-November 2003 Solar Proton Events

    NASA Technical Reports Server (NTRS)

    Lopez-Puertas, M.; Funke, B.; Gil-Lopez, S.; vonClarmann, T.; Stiller, G. P.; Hoepfner, M.; Kellmann, S.; Fischer, H.; Jackman, C. H.

    2005-01-01

    The large solar storms in October-November 2003 produced enormous solar proton events (SPEs) where high energetic particles reached the Earth and penetrated into the middle atmosphere in the polar regions. At this time, the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) was observing the atmosphere in the 6-68 km altitude range. MIPAS observations of NO(x) (NO+NO2) and O3 of the period from 25 October to 14 November 2003 are the first global measurements of NO(x) species, covering both the summer (daylight) and winter (dark) polar regions during an SPE. Very large values of NO(x) in the upper stratosphere of 180 ppbv (parts per billion by volume) have been measured, and a large asymmetry in Northern and Southern polar cap NO(x) enhancements was found. Arctic mean polar cap (>60 deg) NO(x) enhancements of 20 to 70 ppbv between 40 to 60 km lasted for at least two weeks, while the Antarctic mean NO(x) enhancement was between 10 and 35 ppbv and was halved after two weeks. Ozone shows depletion signatures associated with both HO(x) (H+OH+HO2) and NO(x) enhancements but at different time scales. Arctic lower mesospheric (upper stratospheric) ozone is reduced by 50-70% (30-40%) for about two weeks The large solar storms in October-November 2003 produced after the SPEs. A smaller ozone depletion signal was observed in the Antarctic atmosphere. After the locally produced Arctic middle and upper stratospheric as well as mesospheric NO(x) enhancement, large amounts of NO(x) were observed until the end of December. These are explained by downward transport processes.

  2. Variations in radiation and photolysis rates in the southern midlatitudes due to ozone depletion over the Antarctica

    NASA Astrophysics Data System (ADS)

    López Comí, Laura; Morgenstern, Olaf; Zeng, Guang; Masters, Sarah L.

    2013-04-01

    Lauder (45° S, 170° E), a research station located on the South Island of New Zealand, is a clean-air atmospheric observatory representative of southern mid-latitudes. Long-term records of various atmospheric chemical compounds have been measured here for up to three decades. We assess observations of selected atmospheric chemical species, including ozone, and their variability throughout the recording period. By utilizing these observational data and a photolysis scheme (FAST-JX) we will address how changes in the total ozone column and in aerosols at Lauder affect radiation and photolysis rates of different species. The results serve as a stepping stone towards constructing a single-column photolysis model for Lauder constrained with profiles of stable species (e.g. ozone, methane, CO, HCHO, halogen compounds, etc) measured at Lauder to derive variations and trends of shorter-lived species. One of our targets will be changes in the tropospheric oxidizing capacity in the Southern Hemisphere.

  3. New observations of a large concentration of ClO in the springtime lower stratosphere over Antarctica and its implications for ozone-depleting chemistry

    NASA Technical Reports Server (NTRS)

    De Zafra, R. L.; Jaramillo, M.; Barrett, J.; Emmons, L. K.; Solomon, P. M.

    1989-01-01

    New measurements of stratospheric chlorine monoxide (ClO) were made at McMurdo Station, Antarctica, during the austral spring of 1987. Rotational emission line spectroscopy, employing a ground-based detector, was used to determine mixing ratio profiles over the range about 17-45 km. A spectral band pass double that was used for similar measurements in 1986 allowed an improvement to be made in the definition of the anomalous low-altitude stratospheric ClO layer associated with springtime ozone depletion. A peak mixing ratio of 1.6 + or - 0.4 parts per billion by volume (ppbv) (95 percent confidence level) was found at 19.5 + or - 1 km at midday during the period September 20-24, 1987. The observed peak mixing ratio and diurnal behavior are discussed in relation to chemical depletion theories. Calculations indicate that the large observed ClO concentration provides an efficient closure for a catalytic Cl cycle through the ClO dimer mechanism, yielding good agreement with various observed features of O3 depletion.

  4. New observations of a large concentration of ClO in the springtime lower stratosphere over Antarctica and its implications for ozone-depleting chemistry

    NASA Technical Reports Server (NTRS)

    De Zafra, R. L.; Jaramillo, M.; Barrett, J.; Emmons, L. K.; Solomon, P. M.

    1989-01-01

    New measurements of stratospheric chlorine monoxide (ClO) were made at McMurdo Station, Antarctica, during the austral spring of 1987. Rotational emission line spectroscopy, employing a ground-based detector, was used to determine mixing ratio profiles over the range about 17-45 km. A spectral band pass double that was used for similar measurements in 1986 allowed an improvement to be made in the definition of the anomalous low-altitude stratospheric ClO layer associated with springtime ozone depletion. A peak mixing ratio of 1.6 + or - 0.4 parts per billion by volume (ppbv) (95 percent confidence level) was found at 19.5 + or - 1 km at midday during the period September 20-24, 1987. The observed peak mixing ratio and diurnal behavior are discussed in relation to chemical depletion theories. Calculations indicate that the large observed ClO concentration provides an efficient closure for a catalytic Cl cycle through the ClO dimer mechanism, yielding good agreement with various observed features of O3 depletion.

  5. Environmental optimization of continuous flow ozonation for urban wastewater reclamation.

    PubMed

    Rodríguez, Antonio; Muñoz, Iván; Perdigón-Melón, José A; Carbajo, José B; Martínez, María J; Fernández-Alba, Amadeo R; García-Calvo, Eloy; Rosal, Roberto

    2012-10-15

    Wastewater samples from the secondary clarifier of two treatment plants were spiked in the microgram-to-tens-of-microgram per liter range with diuron (herbicide), ibuprofen and diclofenac (anti-inflammatory drugs), sulfamethoxazole and erythromycin (antibiotics), bezafibrate and gemfibrozil (lipid regulators), atenolol (β-blocker), carbamazepine (anti-epileptic), hydrochlorothiazide (diuretic), caffeine (stimulant) and N-acetyl-4-amino-antipiryne, a metabolite of the antipyretic drug dypirone. They were subsequently ozonated in continuous flow using 1.2L lab-scale bubble columns. The concentration of all spiking compounds was monitored in the outlet stream. The effects of varying ozone input, expressed as energy per unit volume, and water flow rate, and of using single or double column were studied in relation to the efficiency of ozone usage and the ratio of pollutant depletion. The ozone dosage required to treat both wastewaters with pollutant depletion of >90% was in the 5.5-8.5 mg/L range with ozone efficiencies greater than 80% depending on the type of wastewater and the operating conditions. This represented 100-200 mol of ozone transferred per mole of pollutant removed. Direct and indirect environmental impacts of ozonation were assessed according to Life Cycle Assessment, a technique that helped identify the most effective treatments in terms of potential toxicity reduction, as well as of toxicity reduction per unit mass of greenhouse-gas emissions, which were used as an indicator of environmental efficiency. A trade-off between environmental effectiveness (toxicity reduction) and greenhouse-gas emissions was observed since maximizing toxicity removal led to higher greenhouse-gas emissions, due to the latter's relatively high ozone requirements. Also, there is an environmental trade-off between effectiveness and efficiency. Our results indicate that an efficient use of ozone was not compatible with a full pollutant removal.

  6. The contribution of greenhouse gases to the recent slowdown in global-mean temperature trends

    NASA Astrophysics Data System (ADS)

    Checa-Garcia, R.; Shine, K. P.; Hegglin, M. I.

    2016-09-01

    The recent slowdown in the rate of increase in global-mean surface temperature (GMST) has generated extensive discussion, but little attention has been given to the contribution of time-varying trends in greenhouse gas concentrations. We use a simple model approach to quantify this contribution. Between 1985 and 2003, greenhouse gases (including well-mixed greenhouse gases, tropospheric and stratospheric ozone, and stratospheric water vapour from methane oxidation) caused a reduction in GMST trend of around 0.03-0.05 K decade-1 which is around 18%-25% of the observed trend over that period. The main contributors to this reduction are the rapid change in the growth rates of ozone-depleting gases (with this contribution slightly opposed by stratospheric ozone depletion itself) and the weakening in growth rates of methane and tropospheric ozone radiative forcing. Although CO2 is the dominant greenhouse gas contributor to GMST trends, the continued increase in CO2 concentrations offsets only about 30% of the simulated trend reduction due to these other contributors. These results emphasize that trends in non-CO2 greenhouse gas concentrations can make significant positive and negative contributions to changes in the rate of warming, and that they need to be considered more closely in analyses of the causes of such variations.

  7. Synthetic greenhouse gases to decline if Montreal Protocol amended

    NASA Astrophysics Data System (ADS)

    Wendel, JoAnna

    2014-07-01

    The Montreal Protocol, an international treaty designed to reduce the release into the atmosphere of ozone-depleting gases such as hydrochlorofluorocarbons and chlorofluorocarbons, has been successful since its implementation in the late 1980s. However, related greenhouse gases, such as hydrofluorocarbons (HFCs), have increased in concentration in the atmosphere since then. HFCs, along with other synthetic greenhouse gases (SGHGs), account for a radiative forcing almost 20% as large as that due to the increase in carbon dioxide (CO2) since the preindustrial era.

  8. New determination of extinction due to atmospheric aerosols and the resulting implications for upper stratospheric ozone depletion

    SciTech Connect

    Manning, J.O.

    1987-01-01

    A crucial question in the statistical analysis of measurements of the vertical distribution of atmospheric ozone centers on the essential aerosol corrections to these data. A lack of global coverage of the atmospheric aerosol content leads to possible biases in these corrections. Limited aerosol data are available for correcting these ozone measurements and are in the from of broad-band transmission data from a single station. With the added uncertainty of the injection altitude of volcanic aerosols, these weaknesses point out the need for a better understanding of the spatial and temporal trends in atmospheric aerosols. To resolve these weaknesses, atmospheric extinction coefficients, which were obtained from astronomical photometric observations, have been compiled, standardized, and analyzed. These extinction coefficients provided a means of extracting the extinction and transmission due specifically to atmospheric aerosols. These aerosol transmissions were analyzed for trends, and the wavelength dependence of the aerosol extinction coefficients was characterized to provide the necessary input for corrections to the measurements of atmospheric ozone.

  9. Analytical Method for the Detection of Ozone Depleting Chemicals (ODC) in Commercial Products Using a Gas Chromatograph with an Electron Capture Detector (GC-ECD)

    SciTech Connect

    Lee, Richard N.; Dockendorff, Brian P.; Wright, Bob W.

    2008-08-01

    This document describes an analytical procedure that was developed for the trace level detection of residual ozone depleting chemicals (ODC) associated with the manufacture of selected commercial products. To ensure the United States meets it obligation under the Montreal Protocol, Congress enacted legislation in 1989 to impose an excise tax on electronic goods imported into the United States that were produced with banned chemicals. This procedure was developed to technically determine if residual ODC chemicals could be detected on electronic circuit boards. The analytical method utilizes a “purge and trap” technique followed by gas chromatography with electron capture detection to capture and analyze the volatile chemicals associated with the matrix. The method describes the procedure, the hardware, operating conditions, calibration, and quality control measures in sufficient detail to allow the capability to be replicated. This document corresponds to internal Standard Operating Procedure (SOP) EFL-130A, Rev 4.

  10. Is the Ozone Hole over Your Classroom?

    ERIC Educational Resources Information Center

    Cordero, Eugene C.

    2002-01-01

    Reports on a survey of first year university science students regarding their understanding of the ozone layer, ozone depletion, and the effect of ozone depletion on Australia. Suggests that better teaching resources for environmental issues such as ozone depletion and global warming are needed before improvements in student understanding can be…

  11. Is the Ozone Hole over Your Classroom?

    ERIC Educational Resources Information Center

    Cordero, Eugene C.

    2002-01-01

    Reports on a survey of first year university science students regarding their understanding of the ozone layer, ozone depletion, and the effect of ozone depletion on Australia. Suggests that better teaching resources for environmental issues such as ozone depletion and global warming are needed before improvements in student understanding can be…

  12. Heterogeneous reactions of N2O5 with H2O and HCl on ice surfaces - Implications for Antarctic ozone depletion

    NASA Technical Reports Server (NTRS)

    Leu, Ming-Taun

    1988-01-01

    This paper reports on the measurements of reaction probabilities for heterogeneous reaction of N2O5 with H2O and HCl on ice surfaces at 195 K, using a fast-flow reactor coupled with a quadrupole mass spectrometer. The reaction probability for N2O5 on pure-water ice was found to be 0.028 + or - 0.011, with nitric acid in the solid phase as the sole product. In the presence of HCl in ice, the probability of N2O5 reaction was enhanced (to 0.037); the reaction produced, besides solid-phase nitric acid, ClNO2 and ClONO which were released into the gas phase within a few milliseconds. The latter two compounds can be readily photolyzed in the austral spring to form active chlorine which would remove stratospheric ozone. It is suggested that, since the polar stratospheric clouds are believed to contain HCl-ice mixture on the surface, the reactions of N2O5 on H2O/HCl particles is a major factor in the Antarctic springtime ozone depletion.

  13. Effect of stratospheric ozone depletion and enhanced ultraviolet radiation on marine bacteria at Palmer Station, Antarctica in the early austral spring.

    PubMed

    Pakulski, J Dean; Kase, Jason P; Meador, Jarah A; Jeffrey, Wade H

    2008-01-01

    We investigated the interactions between ozone-depleted air masses and subsequent changes in UVB on marine bacterial abundance and production at Palmer Station, Antarctica from September to November 1999. During periods of low total column ozone (TCO), bacterial cell concentrations declined by 57%. Photoinhibition of bacterial [(3)H]-leucine (Leu) and [(3)H]-thymidine (TdR) incorporation due to UVB was greatest during periods of low TCO in September and early October. During diel ( approximately 28 h) exposure experiments, light treatment samples exhibited >75-100% inhibition of TdR incorporation by mid-afternoon. Leu incorporation exhibited maximum inhibition (50-100%) at sunset and early evening hours. Leu and TdR incorporation in light treatment samples did not exhibit recovery during subsequent periods of darkness. Bacterial Leu and TdR incorporation rates were inversely related to Setlow Dose during a period of recovery from low TCO. These data further suggested a threshold exposure below which bacterial Leu and TdR incorporation recovered rapidly. Recovery of bacterial production after acute Setlow Dose exposures lagged recovery of TCO and was linearly related to TCO measured 2 days previously. This lag in recovery may have resulted from the energetically expensive repair of UVR-induced DNA damage acquired during periods of low TCO.

  14. Understanding Differences in Chemistry Climate Model Projections of Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Douglass, A. R.; Strahan, S. E.; Oman, L. D.; Stolarski, R. S.

    2014-01-01

    Chemistry climate models (CCMs) are used to project future evolution of stratospheric ozone as concentrations of ozone-depleting substances (ODSs) decrease and greenhouse gases increase, cooling the stratosphere. CCM projections exhibit not only many common features but also a broad range of values for quantities such as year of ozone return to 1980 and global ozone level at the end of the 21st century. Multiple linear regression is applied to each of 14 CCMs to separate ozone response to ODS concentration change from that due to climate change. We show that the sensitivity of lower stratospheric ozone to chlorine change Delta Ozone/Delta inorganic chlorine is a near-linear function of partitioning of total inorganic chlorine into its reservoirs; both inorganic chlorine and its partitioning are largely controlled by lower stratospheric transport. CCMs with best performance on transport diagnostics agree with observations for chlorine reservoirs and produce similar ozone responses to chlorine change. After 2035, differences in Delta Ozone/Delta inorganic chlorine contribute little to the spread in CCM projections as the anthropogenic contribution to inorganic chlorine becomes unimportant. Differences among upper stratospheric ozone increases due to temperature decreases are explained by differences in ozone sensitivity to temperature change Delta Ozone/Delta T due to different contributions from various ozone loss processes, each with its own temperature dependence. Ozone decrease in the tropical lower stratosphere caused by a projected speedup in the Brewer-Dobson circulation may or may not be balanced by ozone increases in the middle- and high-latitude lower stratosphere and upper troposphere. This balance, or lack thereof, contributes most to the spread in late 21st century projections.

  15. Understanding Differences in Chemistry Climate Model Projections of Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Douglass, A. R.; Strahan, S. E.; Oman, L. D.; Stolarski, R. S.

    2014-01-01

    Chemistry climate models (CCMs) are used to project future evolution of stratospheric ozone as concentrations of ozone-depleting substances (ODSs) decrease and greenhouse gases increase, cooling the stratosphere. CCM projections exhibit not only many common features but also a broad range of values for quantities such as year of ozone return to 1980 and global ozone level at the end of the 21st century. Multiple linear regression is applied to each of 14 CCMs to separate ozone response to ODS concentration change from that due to climate change. We show that the sensitivity of lower stratospheric ozone to chlorine change Delta Ozone/Delta inorganic chlorine is a near-linear function of partitioning of total inorganic chlorine into its reservoirs; both inorganic chlorine and its partitioning are largely controlled by lower stratospheric transport. CCMs with best performance on transport diagnostics agree with observations for chlorine reservoirs and produce similar ozone responses to chlorine change. After 2035, differences in Delta Ozone/Delta inorganic chlorine contribute little to the spread in CCM projections as the anthropogenic contribution to inorganic chlorine becomes unimportant. Differences among upper stratospheric ozone increases due to temperature decreases are explained by differences in ozone sensitivity to temperature change Delta Ozone/Delta T due to different contributions from various ozone loss processes, each with its own temperature dependence. Ozone decrease in the tropical lower stratosphere caused by a projected speedup in the Brewer-Dobson circulation may or may not be balanced by ozone increases in the middle- and high-latitude lower stratosphere and upper troposphere. This balance, or lack thereof, contributes most to the spread in late 21st century projections.

  16. Chlorine chemistry and the potential for ozone depletion in the Arctic stratosphere in the winter of 1991/92

    SciTech Connect

    Mueller, R.; Peter, Th.; Crutzen, P.J. ); Oelhaf, H.; Adrian, G.P.; Clarmann, Th.V.; Wegner, A. ); Schmidt, U. ); Lary, D. )

    1994-06-22

    The authors use a chemical box model to study the interaction of atmospheric chemistry processes in the arctic stratosphere, as related to chlorine chemistry. Their objective is to apply this model to study the implications of chlorine chemistry for possible chemical destruction of ozone during the 1991-92 winter. Two major observations from the model were an almost complete conversion of available chlorine to activated forms during the winter, and finally a return of this chlorine to ClONO[sub 2], and after about another month to HCl, as the major reservoir molecular species for chlorine.

  17. Ozone Hole Over Antarctica

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images from the Total Ozone Mapping Spectrometer (TOMS) show the progressive depletion of ozone over Antarctica from 1979 to 1999. This 'ozone hole' has extended to cover an area as large as 10.5 million square miles in September 1998. The previous record of 10.0 million square miles was set in 1996. The Antarctic ozone hole develops each year between late August and early October. Regions with higher levels of ozone are shown in red. NASA and NOAA instruments have been measuring Antarctic ozone levels since the early 1970s. Large regions of depleted ozone began to develop over Antarctica in the early 1980s. Ozone holes of substantial size and depth are likely to continue to form during the next few years, scientists hope to see a reduction in ozone loss as levels of ozone-destroying CFCs (chlorofluorocarbons) are gradually reduced. Credit: Images by Greg Shirah, NASA Goddard Space Flight Center Scientific Visualization Studio

  18. Evolution of the eastward shift in the quasi-stationary minimum of the Antarctic total ozone column

    NASA Astrophysics Data System (ADS)

    Grytsai, Asen; Klekociuk, Andrew; Milinevsky, Gennadi; Evtushevsky, Oleksandr; Stone, Kane

    2017-02-01

    The quasi-stationary pattern of the Antarctic total ozone has changed during the last 4 decades, showing an eastward shift in the zonal ozone minimum. In this work, the association between the longitudinal shift of the zonal ozone minimum and changes in meteorological fields in austral spring (September-November) for 1979-2014 is analyzed using ERA-Interim and NCEP-NCAR reanalyses. Regressive, correlative and anomaly composite analyses are applied to reanalysis data. Patterns of the Southern Annular Mode and quasi-stationary zonal waves 1 and 3 in the meteorological fields show relationships with interannual variability in the longitude of the zonal ozone minimum. On decadal timescales, consistent longitudinal shifts of the zonal ozone minimum and zonal wave 3 pattern in the middle-troposphere temperature at the southern midlatitudes are shown. Attribution runs of the chemistry-climate version of the Australian Community Climate and Earth System Simulator (ACCESS-CCM) model suggest that long-term shifts of the zonal ozone minimum are separately contributed by changes in ozone-depleting substances and greenhouse gases. As is known, Antarctic ozone depletion in spring is strongly projected on the Southern Annular Mode in summer and impacts summertime surface climate across the Southern Hemisphere. The results of this study suggest that changes in zonal ozone asymmetry accompanying ozone depletion could be associated with regional climate changes in the Southern Hemisphere in spring.

  19. Polar ozone

    NASA Technical Reports Server (NTRS)

    Solomon, S.; Grose, W. L.; Jones, R. L.; Mccormick, M. P.; Molina, Mario J.; Oneill, A.; Poole, L. R.; Shine, K. P.; Plumb, R. A.; Pope, V.

    1990-01-01

    The observation and interpretation of a large, unexpected ozone depletion over Antarctica has changed the international scientific view of stratospheric chemistry. The observations which show the veracity, seasonal nature, and vertical structure of the Antarctic ozone hole are presented. Evidence for Arctic and midlatitude ozone loss is also discussed. The chemical theory for Antarctic ozone depletion centers around the occurrence of polar stratospheric clouds (PSCs) in Antarctic winter and spring; the climatology and radiative properties of these clouds are presented. Lab studies of the physical properties of PSCs and the chemical processes that subsequently influence ozone depletion are discussed. Observations and interpretation of the chemical composition of the Antarctic stratosphere are described. It is shown that the observed, greatly enhanced abundances of chlorine monoxide in the lower stratosphere are sufficient to explain much if not all of the ozone decrease. The dynamic meteorology of both polar regions is given, interannual and interhemispheric variations in dynamical processes are outlined, and their likely roles in ozone loss are discussed.

  20. Understanding Differences in Upper Stratospheric Ozone Response to Changes in Chlorine and Temperature as Computed Using CCMVal Models

    NASA Technical Reports Server (NTRS)

    Douglass, A. R.; Stolarski, R. S.; Strahan, S. E.; Oman, L. D.

    2012-01-01

    Projections of future ozone levels are made using models that couple a general circulation model with a representation of atmospheric photochemical processes, allowing interactions among photochemical processes, radiation, and dynamics. Such models are known as chemistry and climate models (CCMs). Although developed from common principles and subject to the same boundary conditions, simulated ozone time series vary for projections of changes in ozone depleting substances (ODSs) and greenhouse gases. In the upper stratosphere photochemical processes control ozone level, and ozone increases as ODSs decrease and temperature decreases due to greenhouse gas increase. Simulations agree broadly but there are quantitative differences in the sensitivity of ozone to chlorine and to temperature. We obtain insight into these differences in sensitivity by examining the relationship between the upper stratosphere annual cycle of ozone and temperature as produced by a suite of models. All simulations conform to expectation in that ozone is less sensitive to temperature when chlorine levels are highest because chlorine catalyzed loss is nearly independent of temperature. Differences in sensitivity are traced to differences in simulated temperature, ozone and reactive nitrogen when chlorine levels are close to background. This work shows that differences in the importance of specific processes underlie differences in simulated sensitivity of ozone to composition change. This suggests a) the multi-model mean is not a best estimate of the sensitivity of upper ozone to changes in ODSs and temperature; b) the spread of values is not an appropriate measure of uncertainty.

  1. Influence of the greenhouse effect on human health through stratospheric cooling: Possible increase in acquired immunodeficiency syndrome

    SciTech Connect

    Okamoto, Kazuto; Tsushima, Hiroshi; Tanimoto, Shin

    1996-12-31

    The greenhouse effect cools the stratosphere and enhances ozone depletion by heterogeneous processes via PSC (polar stratospheric cloud) in polar regions, because at low temperatures PSC formation increases. The ozone depletion thus enhanced could diffuse to lower latitudes. A resultant increase in ultraviolet radiation (UV) would be dangerous for residents in this region because of their thin skin color. It might increase acquired immunodeficiency syndrome (AIDS) through several factors. (1) Reduction of immunoresistance, (21) direct activation of human immunodeficiency virus (HIV), and (3) increase of active oxygen radicals. Epidemiological studies are made to test this hypothesis.

  2. Protecting the Ozone Shield: A New Public Policy

    DTIC Science & Technology

    1991-04-01

    Public Policy Issue; Alterna- 11 tives; Risk Management; Clean Air Act; Global Warming 16. PRICE CODE 17. SECURITY CLASSIFICATION 𔄂. SECURITY...pattern of global warming , commonly known as "the greenhouse effect. 1 OVERVIEW OF THE OZONE DEPLETION PUBLIC POLICY ISSUE In 1974, two atmospheric...inhabitants from the harmful effects of increased UVb radiation and global warming . Another dilemma surrounds this public policy issue since the first

  3. Detection and Attribution of the Recovery of Polar Ozone

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, E. R.; Douglass, A. R.; Nielsen, J. E.; Pawson, S.; Stolarski, R. S.

    2008-01-01

    The Antarctic ozone hole develops each year and culminates by early spring (late September - early October). The severity of the hole has been assessed from satellites using the minimum total ozone value from the October monthly mean (depth of the hole), calculating the average area coverage during this September-October period, and by estimating ozone mass deficit. Profile information shows that ozone is completely destroyed in the 14-2 1 km layer by early October. Ozone is mainly destroyed by halogen (chlorine and bromine) catalytic cycles, and these losses are modulated by temperature variations. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Both models and projections of ozone depleting substances (ODSs) into the 21St century reveal that polar ozone levels should recover in the 2060- 2070 period. In this talk, we will review current projections of polar ozone recovery. Using models and ODs projections, we explore both the past, near future (2008-2025), and far future (> 2025) levels of polar ozone. Finally, we will discuss various factors that complicate recovery such as greenhouse gas changes (e.g., cooling in the upper stratosphere) and the acceleration of the Brewer-Dobson circulation.

  4. Detection and Attribution of the Recovery of Polar Ozone

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, E. R.; Douglass, A. R.; Nielsen, J. E.; Pawson, S.; Stolarski, R. S.

    2008-01-01

    The Antarctic ozone hole develops each year and culminates by early spring (late September - early October). The severity of the hole has been assessed from satellites using the minimum total ozone value from the October monthly mean (depth of the hole), calculating the average area coverage during this September-October period, and by estimating ozone mass deficit. Profile information shows that ozone is completely destroyed in the 14-2 1 km layer by early October. Ozone is mainly destroyed by halogen (chlorine and bromine) catalytic cycles, and these losses are modulated by temperature variations. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Both models and projections of ozone depleting substances (ODSs) into the 21St century reveal that polar ozone levels should recover in the 2060- 2070 period. In this talk, we will review current projections of polar ozone recovery. Using models and ODs projections, we explore both the past, near future (2008-2025), and far future (> 2025) levels of polar ozone. Finally, we will discuss various factors that complicate recovery such as greenhouse gas changes (e.g., cooling in the upper stratosphere) and the acceleration of the Brewer-Dobson circulation.

  5. In-situ measurements of chlorine activation, nitric acid redistribution and ozone depletion in the Antarctic lower vortex aboard the German research aircraft HALO during TACTS/ESMVal

    NASA Astrophysics Data System (ADS)

    Jurkat, Tina; Voigt, Christiane; Kaufmann, Stefan; Schlage, Romy; Gottschaldt, Klaus-Dirk; Ziereis, Helmut; Hoor, Peter; Bozem, Heiko; Müller, Stefan; Zahn, Andreas; Schlager, Hans; Oelhaf, Hermann; Sinnhuber, Björn-Martin; Dörnbrack, Andreas

    2016-04-01

    In-situ measurements of stratospheric chlorine compounds are rare and exhibit the potential to gain insight into small scale mixing processes where stratospheric air masses of different origin and history interact. In addition, the relationship with chemically stable trace gases helps to identify regions that have been modified by chemical processing on polar stratospheric clouds. To this end, in-situ measurements of ClONO2, HCl, HNO3, NOy, N2O and O3 have been performed in the Antarctic Polar Vortex in September 2012 aboard the German research aircraft HALO (High Altitude and Long Rang research aircraft) during the TACTS/ESMVal (Transport and Composition in the UTLS/Earth System Model Validation) mission. With take-off and landing in Capetown, HALO sampled vortex air with latitudes down to 65°S, at altitudes between 8 and 14.3 km and potential temperatures between 340 and 390 K. Before intering the vortex at 350 K potential temperature, HALO additionally sampled mid-latitude stratospheric air. The trace gas distributions at the edge of the Antarctic polar vortex show distinct signatures of processed upper stratospheric vortex air and chemically different lower stratospheric / upper tropospheric air. Diabatic descend of the vortex transports processed air into the lower stratosphere. Here small scale filaments of only a few kilometers extension form at the lower vortex boundary due to shear stress, ultimately leading to transport and irreversible mixing. Comparison of trace gas relationships with those at the beginning of the polar winter reveals substantial chlorine activation, ozone depletion de- and renitrification with high resolution. Furthermore, the measurements are compared to the chemistry climate models EMAC and supported by ECMWF analysis. Finally, we compare the Antarctic measurements with new measurements of ClONO2, HCl and HNO3 aboard HALO obtained during the Arctic mission POLSTRACC (POLar STratosphere in a Changing Climate) based in Kiruna (Sveden

  6. Delayed climate change in the Southern Hemisphere induced by stratospheric ozone recovery, as projected by the CMIP5 models (Invited)

    NASA Astrophysics Data System (ADS)

    Polvani, L. M.; Barnes, E. A.

    2013-12-01

    Stratospheric ozone is expected to recover in the second half of this century, due to the regulation of ozone depleting substances by the Montreal Protocol. Targeted modeling studies have suggested that the climate response to ozone recovery will greatly oppose the climate response to increasing greenhouse-gases (GHG); owever, the extent of this cancellation remains unclear, as few such studies are available. Here, we analyze the much larger set of models participating in the Coupled Model Intercomparison Project, phase 5 (CMIP5), all of which include stratospheric ozone depletion and recovery. We show that the closing of the ozone hole will cause a delay in summer-time (DJF) Southern Hemisphere climate change, between now and mid-century. Specifically, we find that the position of the jet stream, the width of the subtropical dry-zones, the seasonality of surface temperatures, and sea ice concentrations all exhibit significantly reduced summer-time trends over the first half of the 21st Century as a consequence of ozone recovery. Beyond mid-century, forcing from GHG emissions begins to dominate the climate response. We also compare the relative influences of future GHG emissions and historic ozone depletion, and find that the simulated DJF tropospheric circulation changes in the Southern Hemisphere between 1965-2005 -- driven primarily by ozone depletion -- are larger than the projected changes in any future scenario over the entire 21st Century.

  7. Exhaust emissions of volatile organic compounds of powered two-wheelers: effect of cold start and vehicle speed. Contribution to greenhouse effect and tropospheric ozone formation.

    PubMed

    Costagliola, M Antonietta; Murena, Fabio; Prati, M Vittoria

    2014-01-15

    Powered two-wheeler (PTW) vehicles complying with recent European type approval standards (stages Euro 2 and Euro 3) were tested on chassis dynamometer in order to measure exhaust emissions of about 25 volatile organic compounds (VOCs) in the range C1-C7, including carcinogenic compounds as benzene and 1,3-butadiene. The fleet consists of a moped (engine capacity ≤ 50 cm(3)) and three fuel injection motorcycles of different engine capacities (150, 300 and 400 cm(3)). Different driving conditions were tested (US FPT cycle, constant speed). Due to the poor control of the combustion and catalyst efficiency, moped is the highest pollutant emitter. In fact, fuel injection strategy and three way catalyst with lambda sensor are able to reduce VOC motorcycles' emission of about one order of magnitude with respect to moped. Cold start effect, that is crucial for the assessment of actual emission of PTWs in urban areas, was significant: 30-51% of extra emission for methane. In the investigated speed range, moped showed a significant maximum of VOC emission factor at minimum speed (10 km/h) and a slightly decreasing trend from 20 to 60 km/h; motorcycles showed on the average a less significant peak at 10 km/h, a minimum at 30-40 km/h and then an increasing trend with a maximum emission factor at 90 km/h. Carcinogenic VOCs show the same pattern of total VOCs. Ozone Formation Potential (OFP) was estimated by using Maximum Incremental Reactivity scale. The greatest contribution to tropospheric ozone formation comes from alkenes group which account for 50-80% to the total OFP. VOC contribution effect on greenhouse effect is negligible with respect to CO2 emitted. © 2013.

  8. The Future of the Stratosphere and the Ozone Layer

    NASA Astrophysics Data System (ADS)

    Newman, P. A.; Oman, L.; Pawson, S.; Fleming, E. L.; Li, F.; Jackman, C. H.

    2014-12-01

    Stratospheric ozone has been slightly depleted (2-4 % globally) by emissions of ozone depleting substances (ODSs). The landmark 1987 Montreal Protocol led to the end of most these ODS emissions, and total levels of ODSs have been declining since the late 1990s. The interim replacements for these ODSs were hydroclorofluorocarbons (HCFCs), but these HCFCs have also now been regulated. The period in which stratospheric change has been dominated by CFC-induced ozone loss (the "CFC era") is now coming to an end, as a period begins when the impacts of stratospheric circulation and chemistry changes induced by Greenhouse Gas increases (the "GHG era"). The stratosphere GHG-era will be characterized by continued decreases of ODSs and increases of CO2, N2O, and CH4. In this talk, we will describe how these factors will modify stratospheric ozone levels and the basic stratospheric climatology: CO2 and CH4 increases will increase stratospheric ozone, while N2O increases will decrease stratospheric ozone. In particular, GHG increases and the associated warming of the troposphere will modify stratospheric transport and cool the upper stratosphere. We will quantitatively show the contributions by various GHGs to these changes and the specifics of the chemical, dynamical, and radiative changes. Further, we will show how the stratosphere evolves under future GHG projections from the various Representative Concentration Pathways, illustrating the different changes in stratospheric ozone caused by the concurrent radiative, chemical and dynamical impacts of GHG changes.

  9. Quantifying Uncertainty in Projections of Stratospheric Ozone Over the 21st Century

    NASA Technical Reports Server (NTRS)

    Charlton-Perez, A. J.; Hawkins, E.; Eyring, V.; Cionni, I.; Bodeker, G. E.; Kinnison, D. E.; Akiyoshi, H.; Frith, S. M.; Garcia, R.; Gettelman, A.; Lamarque, J. F.; Nakamura, T.; Pawson, S.; Yamashita, Y.; Bekki, S.; Braesicke, P.; Chipperfield, M. P.; Dhomse, S.; Marchand, M.; Mancini, E.; Morgenstern, O.; Pitari, G.; Plummer, D.; Pyle, J. A.; Rozanov, E.

    2010-01-01

    Future stratospheric ozone concentrations will be determined both by changes in the concentration of ozone depleting substances (ODSs) and by changes in stratospheric and tropospheric climate, including those caused by changes in anthropogenic greenhouse gases (GHGs). Since future economic development pathways and resultant emissions of GHGs are uncertain, anthropogenic climate change could be a significant source of uncertainty for future projections of stratospheric ozone. In this pilot study, using an ensemble of opportunity of chemistry-climate model (CCM) simulations, the contribution of scenario uncertainty from different plausible emissions pathways for 10 ODSs and GHGs to future ozone projections is quantified relative to the contribution from model uncertainty and internal variability of the chemistry-climate system. For both the global, annual mean ozone concentration and for ozone in specific geographical regions, differences between CCMs are the dominant source of uncertainty for the first two-thirds of the 21 st century, up-to and after the time when ozone concentrations 15 return to 1980 values. In the last third of the 21st century, dependent upon the set of greenhouse gas scenarios used, scenario uncertainty can be the dominant contributor. This result suggests that investment in chemistry-climate modelling is likely to continue to refine projections of stratospheric ozone and estimates of the return of stratospheric ozone concentrations to pre-1980 levels.

  10. Ozone: What Would It Be Like to Live in a World Where the Sun Was Dangerous?

    ERIC Educational Resources Information Center

    Clearing, 1992

    1992-01-01

    Defines ozone layer and the meaning, evidence, causes, and significance of ozone depletion. Summarizes solutions to the problem of ozone depletion and government action concerning the issue. Graphically depicts ozone depletion, global ozone loss, and how ozone is destroyed. Provides a lesson plan and listing for additional educational resources.…

  11. Ozone: What Would It Be Like to Live in a World Where the Sun Was Dangerous?

    ERIC Educational Resources Information Center

    Clearing, 1992

    1992-01-01

    Defines ozone layer and the meaning, evidence, causes, and significance of ozone depletion. Summarizes solutions to the problem of ozone depletion and government action concerning the issue. Graphically depicts ozone depletion, global ozone loss, and how ozone is destroyed. Provides a lesson plan and listing for additional educational resources.…

  12. Effects of a polar stratosphere cloud parameterization on ozone depletion due to stratospheric aircraft in a two-dimensional model

    NASA Technical Reports Server (NTRS)

    Considine, David B.; Douglass, Anne R.; Jackman, Charles H.

    1994-01-01

    A parameterization of Type 1 and 2 polar stratospheric cloud (PSC) formation is presented which is appropriate for use in two-dimensional (2-D) photochemical models of the stratosphere. The calculations of PSC frequency of occurrence and surface area density uses climatological temperature probability distributions obtained from National Meteorological Center data to avoid using zonal mean temperatures, which are not good predictors of PSC behavior. The parameterization does not attempt to model the microphysics of PSCs. The parameterization predicts changes in PSC formation and heterogeneous processing due to perturbations of stratospheric trace constituents. It is therefore useful in assessing the potential effects of a fleet of stratospheric aircraft (high speed civil transports, or HSCTs) on stratospheric composition. the model calculated frequency of PSC occurrence agrees well with a climatology based on stratospheric aerosol measurement (SAM) 2 observations. PSCs are predicted to occur in the tropics. Their vertical range is narrow, however, and their impact on model O3 fields is small. When PSC and sulfate aerosol heterogeneous processes are included in the model calculations, the O3 change for 1980 - 1990 is in substantially better agreement with the total ozone mapping spectrometer (TOMS)-derived O3 trend than otherwise. The overall changes in model O3 response to standard HSCT perturbation scenarios produced by the parameterization are small and tend to decrease the model sensitivity to the HSCT perturbation. However, in the southern hemisphere spring a significant increase in O3 sensitivity to HSCT perturbations is found. At this location and time, increased PSC formation leads to increased levels of active chlorine, which produce the O3 decreases.

  13. Effects of a polar stratosphere cloud parameterization on ozone depletion due to stratospheric aircraft in a two-dimensional model

    NASA Technical Reports Server (NTRS)

    Considine, David B.; Douglass, Anne R.; Jackman, Charles H.

    1994-01-01

    A parameterization of Type 1 and 2 polar stratospheric cloud (PSC) formation is presented which is appropriate for use in two-dimensional (2-D) photochemical models of the stratosphere. The calculations of PSC frequency of occurrence and surface area density uses climatological temperature probability distributions obtained from National Meteorological Center data to avoid using zonal mean temperatures, which are not good predictors of PSC behavior. The parameterization does not attempt to model the microphysics of PSCs. The parameterization predicts changes in PSC formation and heterogeneous processing due to perturbations of stratospheric trace constituents. It is therefore useful in assessing the potential effects of a fleet of stratospheric aircraft (high speed civil transports, or HSCTs) on stratospheric composition. the model calculated frequency of PSC occurrence agrees well with a climatology based on stratospheric aerosol measurement (SAM) 2 observations. PSCs are predicted to occur in the tropics. Their vertical range is narrow, however, and their impact on model O3 fields is small. When PSC and sulfate aerosol heterogeneous processes are included in the model calculations, the O3 change for 1980 - 1990 is in substantially better agreement with the total ozone mapping spectrometer (TOMS)-derived O3 trend than otherwise. The overall changes in model O3 response to standard HSCT perturbation scenarios produced by the parameterization are small and tend to decrease the model sensitivity to the HSCT perturbation. However, in the southern hemisphere spring a significant increase in O3 sensitivity to HSCT perturbations is found. At this location and time, increased PSC formation leads to increased levels of active chlorine, which produce the O3 decreases.

  14. Impacts of the production and consumption of biofuels on stratospheric ozone

    NASA Astrophysics Data System (ADS)

    Revell, Laura E.; Bodeker, Greg E.; Huck, Petra E.; Williamson, Bryce E.

    2012-05-01

    Biofuels are becoming increasingly popular sources of renewable energy as economic pressures and environmental consequences encourage the use of alternatives to fossil fuels. However, growing crops destined for use as biofuels incurs large N2O emissions associated with the use of nitrogen-based fertilizers. Besides being a greenhouse gas, N2O is also the primary source of stratospheric NOx (NO + NO2) which leads to stratospheric ozone depletion. In this paper, the potential effects on the ozone layer of a large-scale shift away from fossil fuel use to biofuels consumption over the 21st century are examined. Under such a scenario, global-mean column ozone decreases by 2.6 DU between 2010 and 2100 in contrast to a 0.7 DU decrease under a control simulation (the IPCC SRES B1 scenario for greenhouse gases) and a 9.1 DU increase under the more commonly used SRES A1B scenario. Two factors cause the decrease in ozone in the biofuels simulation: 1) large N2O emissions lead to faster rates of the ozone-depleting NOx cycles and; 2) reduced CO2 emissions (due to less fossil fuel burning) lead to relatively less stratospheric cooling over the 21st century, which decreases ozone abundances. Reducing CO2 emissions while neglecting to reduce N2O emissions could therefore be damaging to the ozone layer.

  15. Primary Student-Teachers' Conceptual Understanding of the Greenhouse Effect: A mixed method study

    NASA Astrophysics Data System (ADS)

    Ratinen, Ilkka Johannes

    2013-04-01

    The greenhouse effect is a reasonably complex scientific phenomenon which can be used as a model to examine students' conceptual understanding in science. Primary student-teachers' understanding of global environmental problems, such as climate change and ozone depletion, indicates that they have many misconceptions. The present mixed method study examines Finnish primary student-teachers' understanding of the greenhouse effect based on the results obtained via open-ended and closed-form questionnaires. The open-ended questionnaire considers primary student-teachers' spontaneous ideas about the greenhouse effect depicted by concept maps. The present study also uses statistical analysis to reveal respondents' conceptualization of the greenhouse effect. The concept maps and statistical analysis reveal that the primary student-teachers' factual knowledge and their conceptual understanding of the greenhouse effect are incomplete and even misleading. In the light of the results of the present study, proposals for modifying the instruction of climate change in science, especially in geography, are presented.

  16. Rotational Spectroscopy of Newly Detected Atmospheric Ozone Depleters: CF_3CH_2Cl, CF_3CCl_3, and CF_2ClCCl_3

    NASA Astrophysics Data System (ADS)

    Kisiel, Zbigniew; Bialkowska-Jaworska, Ewa; Pszczólkowski, Lech; Uriarte, Iciar; Ecija, Patricia; Basterretxea, Francisco J.; Cocinero, Emilio J.

    2015-06-01

    In a recent study of unpolluted air samples from Tasmania and of deep firn snow in Greenland four previously overlooked ozone-depleting substances have been identified. These compounds started to emerge in the atmosphere in the 1960s, and two: CF_3CCl_3 (CFC-113a) and CF_3CH_2Cl (HCHF-133a) continue to accumulate in the atmosphere. Three of the four compounds have non-zero dipole moments and are amenable to study by rotational spectroscopy, establishing the basis for analytic applications. Relatively limited studies have been reported for CF_3CH_2Cl and CF_3CCl_3, while CF_2ClCCl_3 has not yet been studied by this technique. We presently report extensive results obtained for all three compounds, resulting from concerted application of supersonic expansion FTMW spectroscopy in chirped pulse and cavity modes, and room-temperature MMW spectroscopy. Among the plentiful results, we have been able to resolve and fit the complex nuclear quadrupole hyperfine splitting. J.C.Laube, et al., Nature Geoscience 7, 266 (2014). Ogata, et al., J. Mol. Struct. 144, 1 (1986). R.Holm, et al., Z. Naturforsch. 23a, 1040 (1968). J.H.Carpenter et al., J. Mol. Spectrosc. 154, 207 (1992); P.J.Seo et al., J. Mol. Spectrosc. 169, 58 (1995).

  17. Model evaluation of the radiative and temperature effects of the ozone content changes in the global atmosphere of 1980's

    NASA Technical Reports Server (NTRS)

    Karol, Igor L.; Frolkis, Victor A.

    1994-01-01

    Radiative and temperature effects of the observed ozone and greenhouse gas atmospheric content changes in 1980 - 1990 are evaluated using the two-dimensional energy balance radiative-convective model of the zonally and annually averaged troposphere and stratosphere. Calculated radiative flux changes for standard conditions quantitatively agree with their estimates in WMO/UNEP 1991 review. Model estimates indicate rather small influence of ozone depletion in the lower stratosphere on the greenhouse tropospheric warming rate, being more significant in the non-tropical Southern Hemisphere. The calculated cooling of the lower stratosphere is close to the observed temperature trends there in the last decade.

  18. Acute inhalation toxicity evaluation of a 93:7 mixture of perfluoro-2-butene and 1-bromopropane, a replacement candidate for ozone depleting substances. Interim report, July--August 1997

    SciTech Connect

    Feldmann, M.L.; Leahy, H.F.; Vinegar, A.

    1997-10-01

    The DoD requires the development of toxicity profiles for chemical substitute candidates proposed to replace ozone depleting substances such as chloro- and fluorocarbons and halons. A 93:7 mixture of perfluoro-2-butene and 1-bromopropane was identified as a possible replacement candidate for ozone-depleting fire extinguishants. An acute inhalation toxicity test utilizing male and female Fischer 344 rats was performed on this test material. No deaths occurred in any of the rats exposed to 5.3 mg/L of the 93:7 perfluoro-2-butene and 1-bromopropane mixture. Body weights of male and female rats during the subsequent 14-day observation period were unaffected by treatment. The test material did not produce acute toxicity via the inhalation route.

  19. Space-borne remote sensing with active optical instruments for the measurement of temperature, pressure, ozone and the greenhouse gases CO2, CH4, and N2O

    NASA Astrophysics Data System (ADS)

    Ehret, G.; Fix, A.; Kiemle, C.; Wirth, M.

    Lidar Light Detection and Ranging is regarded as an innovative component of the global observing system It offers the possibility to directly sample the four-dimensional variability of the atmosphere with unprecedented accuracy and spatial resolution In Europe space-borne lidar systems have been the subject of extensive investigations since mid 1970 s resulting in mission and instrument concepts such as ATLID a backscatter lidar for aerosol and clouds for the EarthCARE mission or ALADIN a Doppler wind lidar considered for the ADM Aeolus mission Major advances particularly in humidity profiling are expected from the space-borne Differential Absorption Lidar DIAL being the Core instrument of the WALES Water Vapour Lidar Experiment in Space mission which was studied up to a level of Phase A In this presentation we report on the background definition of a future lidar system capable of monitoring the greenhouse gases carbon dioxide CO 2 methane CH 4 and nitrous oxide N 2 O stratospheric and tropospheric ozone O 3 and the meteorological parameter pressure p and temperature T The idea of this study which was initiated by the European Space Agency ESA was to select one or two candidate instruments for follow-on activities on sensor and mission level For each parameter appropriate performance models of active optical instruments either for range-resolved or for total column measurements were defined and implemented as computer codes for parametric analysis The sampling strategy and error characteristics for the

  20. Options to Accelerate Ozone Recovery: Ozone and Climate Benefits

    NASA Technical Reports Server (NTRS)

    Fleming, E. L.; Daniel, J. S.; Portmann, R. W.; Velders, G. J. M.; Jackman, C. H.; Ravishankara, A. R.

    2010-01-01

    The humankind or anthropogenic influence on ozone primarily originated from the chlorofluorocarbons and halons (chlorine and bromine). Representatives from governments have met periodically over the years to establish international regulations starting with the Montreal Protocol in 1987, which greatly limited the release of these ozone-depleting substances (DDSs). Two global models have been used to investigate the impact of hypothetical reductions in future emissions of ODSs on total column ozone. The investigations primarily focused on chlorine- and bromine-containing gases, but some computations also included nitrous oxide (N2O). The Montreal Protocol with ODS controls have been so successful that further regulations of chlorine- and bromine-containing gases could have only a fraction of the impact that regulations already in force have had. if all anthropogenic ODS emissions were halted beginning in 2011, ozone is calculated to be higher by about 1-2% during the period 2030-2100 compared to a case of no additional ODS restrictions. Chlorine- and bromine-containing gases and nitrous oxide are also greenhouse gases and lead to warming of the troposphere. Elimination of N 20 emissions would result in a reduction of radiative forcing of 0.23 W/sq m in 2100 than presently computed and destruction of the CFC bank would produce a reduction in radiative forcing of 0.005 W/sq m in 2100. This paper provides a quantitative way to consider future regulations of the CFC bank and N 20 emissions