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Sample records for affect stratospheric ozone

  1. Studies of dynamical processes affecting the distribution of stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Bowman, Kenneth P.

    1993-01-01

    The purpose of the research was to understand large-scale tracer transport processes in the stratosphere. Two approaches were taken. The first is analysis of tracer observations, especially satellite observations of ozone concentration and total column ozone. The second is numerical simulation of tracer transport processes. Topics researched include: quasi-biennial oscillation (QBO) and stratospheric ozone; mixing in the polar vortices; polar stratospheric clouds (PSC) properties from Antarctic lidar data; and statistical methods for numerical experiments.

  2. Ozone and the stratosphere

    NASA Technical Reports Server (NTRS)

    Shimazaki, Tatsuo

    1987-01-01

    It is shown that the stratospheric ozone is effective in absorbing almost all radiation below 300 nm at heights below 300 km. The distribution of global ozone in the troposphere and the lower stratosphere, and the latitudinal variations of the total ozone column over four seasons are considered. The theory of the ozone layer production is discussed together with catalytic reactions for ozone loss and the mechanisms of ozone transport. Special attention is given to the anthropogenic perturbations, such as SST exhaust gases and freon gas from aerosol cans and refrigerators, that may cause an extensive destruction of the stratospheric ozone layer and thus have a profound impact on the world climate and on life.

  3. Ultraviolet Radiation and Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Stolarski, R.

    2003-01-01

    Ultraviolet radiation from the sun produces ozone in the stratosphere and it participates in the destruction of ozone. Absorption of solar ultraviolet radiation by ozone is the primary heating mechanism leading to the maximum in temperature at the stratopause. Variations of solar ultraviolet radiation on both the 27-day solar rotation period and the 11-year solar cycle affect ozone by several mechanisms. The temperature and ozone in the upper stratosphere respond to solar uv variations as a coupled system. An increase in uv leads to an increase in the production of ozone through the photolysis of molecular oxygen. An increase in uv leads to an increase in temperature through the heating by ozone photolysis. The increase in temperature leads to a partially-offsetting decrease in ozone through temperature-dependent reaction rate coefficients. The ozone variation modulates the heating by ozone photolysis. The increase in ozone at solar maximum enhances the uv heating. The processes are understood and supported by long-term data sets. Variation in the upper stratospheric temperatures will lead to a change in the behavior of waves propagating upward from the troposphere. Changes in the pattern of wave dissipation will lead to acceleration or deceleration of the mean flow and changes in the residual or transport circulation. This mechanism could lead to the propagation of the solar cycle uv variation from the upper stratosphere downward to the lower stratosphere. This process is not well-understood and has been the subject of an increasing number of model studies. I will review the data analyses for solar cycle and their comparison to model results.

  4. Changes in stratospheric ozone.

    PubMed

    Cicerone, R J

    1987-07-01

    The ozone layer in the upper atmosphere is a natural feature of the earth's environment. It performs several important functions, including shielding the earth from damaging solar ultraviolet radiation. Far from being static, ozone concentrations rise and fall under the forces of photochemical production, catalytic chemical destruction, and fluid dynamical transport. Human activities are projected to deplete substantially stratospheric ozone through anthropogenic increases in the global concentrations of key atmospheric chemicals. Human-induced perturbations may be occurring already.

  5. 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.

  6. 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

  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. PMID:16627294

  8. What Do We Need To Do To Improve Our Understanding of How Volcanoes Affect Stratospheric Ozone?

    NASA Astrophysics Data System (ADS)

    Solomon, S.

    2015-12-01

    This talk will briefly survey what is known and what is not known about stratospheric ozone depletion and volcanic events, and will describe some ways to improve our understanding. Observations of total ozone following the eruption of El Chichon in the 1980s provided some of the earliest and clearest indications of the importance of volcanic aerosol on ozone depletion. In subsequent decades, improved laboratory information, modeling studies, and observations showed how heterogeneous chemical processing on and in volcanic aerosols could enhance chlorine-catalyzed ozone loss in the lower stratosphere, while decreasing nitrogen-catalyzed ozone loss in the upper stratosphere. Recent satellite observations shed important light on this chemistry but major gaps in understanding remain, including for example a lack of knowledge of whether hydrochloric acid can be efficiently taken up in stratospheric particles under cold conditions, interactions and competition between volcanic aerosols and ice clouds, and the effects of volcanic aerosols on chemistry in the tropopause region. Effects of volcanic aerosols on Arctic and Antarctic ozone depletion are also subject to many certainties, owing in large part to observational deficiencies. Implications for gaining an improved understanding through both laboratory studies and new observations will be briefly described.

  9. Dynamical factors affecting ozone mixing ratios in the Antarctic lower stratosphere

    NASA Technical Reports Server (NTRS)

    Shiotani, Masato; Gille, John C.

    1987-01-01

    An account is given of the climatology and interannual variability of dynamical quantities and ozone mixing ratios during the Southern Hemisphere spring for 1979-1984. The seasonal variation in temperature in the lower stratosphere is repeatable; a steep decrease in zonal mean ozone mixing ratios is observed around 60 deg S toward the South Pole in September which, with time, becomes shallower in association with minor warmings and a final warming. Climatological synoptic charts in the lower stratosphere show the circumpolar circulation in the geopotential height field and the prominence of planetary wave 1 in the temperature and ozone fields. When wave activity is strong, there are weaker westeries, higher temperatures, and higher ozone mixing ratios at high latitudes.

  10. Effects of stratospheric ozone recovery on photochemistry and ozone air quality in the troposphere

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Wu, S.; Huang, Y.; Wang, Y.

    2014-04-01

    There has been significant stratospheric ozone depletion since the late 1970s due to ozone-depleting substances (ODSs). With the implementation of the Montreal Protocol and its amendments and adjustments, stratospheric ozone is expected to recover towards its pre-1980 level in the coming decades. In this study, we examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). With a full recovery of the stratospheric ozone, the projected increases in ozone column range from 1% over the low latitudes to more than 10% over the polar regions. The sensitivity factor of troposphere ozone photolysis rate, defined as the percentage changes in surface ozone photolysis rate for 1% increase in stratospheric ozone column, shows significant seasonal variation but is always negative with absolute value larger than one. The expected stratospheric ozone recovery is found to affect the tropospheric ozone destruction rates much more than the ozone production rates. Significant decreases in surface ozone photolysis rates due to stratospheric ozone recovery are simulated. The global average tropospheric OH decreases by 1.7%, and the global average lifetime of tropospheric ozone increases by 1.5%. The perturbations to tropospheric ozone and surface ozone show large seasonal and spatial variations. General increases in surface ozone are calculated for each season, with increases by up to 0.8 ppbv in the remote areas. Increases in ozone lifetime by up to 13% are found in the troposphere. The increased lifetimes of tropospheric ozone in response to stratospheric ozone recovery enhance the intercontinental transport of ozone and global pollution, in particular for the summertime. The global background ozone attributable to Asian emissions is calculated to increase by up to 15% or 0.3 ppbv in the Northern Hemisphere in response to the projected stratospheric ozone recovery.

  11. Stratospheric ozone effects on temperature.

    PubMed

    Reck, R A

    1976-05-01

    Calculated surface temperature changes, DeltaT(8), due to stratospheric ozone depletion (at 35 degrees N latitude in April) are less than previously estimated and range between -0.6 and +0.9 degrees K. The sign of DeltaT(8), is determined by the surface albedo and the presence or absence of a low-lying particulate layer (heating with particles, cooling without particles). The calculations indicate that a 90 percent stratospheric ozone depletion does not cause the temperature inversion at the tropopause to vanish, although it is weakened substantially.

  12. The contribution of ozone to future stratospheric temperature trends

    NASA Astrophysics Data System (ADS)

    Maycock, A. C.

    2016-05-01

    The projected recovery of ozone from the effects of ozone depleting substances this century will modulate the stratospheric cooling due to CO2, thereby affecting the detection and attribution of stratospheric temperature trends. Here the impact of future ozone changes on stratospheric temperatures is quantified for three representative concentration pathways (RCPs) using simulations from the Fifth Coupled Model Intercomparison Project (CMIP5). For models with interactive chemistry, ozone trends offset ~50% of the global annual mean upper stratospheric cooling due to CO2 for RCP4.5 and 20% for RCP8.5 between 2006-2015 and 2090-2099. For RCP2.6, ozone trends cause a net warming of the upper and lower stratosphere. The misspecification of ozone trends for RCP2.6/RCP4.5 in models that used the International Global Atmospheric Chemistry (IGAC)/Stratosphere-troposphere Processes and their Role in Climate (SPARC) Ozone Database causes anomalous warming (cooling) of the upper (lower) stratosphere compared to chemistry-climate models. The dependence of ozone chemistry on greenhouse gas concentrations should therefore be better represented in CMIP6.

  13. 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

  14. Detection of stratospheric ozone intrusions by windprofiler radars.

    PubMed

    Hocking, W K; Carey-Smith, T; Tarasick, D W; Argall, P S; Strong, K; Rochon, Y; Zawadzki, I; Taylor, P A

    2007-11-01

    Stratospheric ozone attenuates harmful ultraviolet radiation and protects the Earth's biosphere. Ozone is also of fundamental importance for the chemistry of the lowermost part of the atmosphere, the troposphere. At ground level, ozone is an important by-product of anthropogenic pollution, damaging forests and crops, and negatively affecting human health. Ozone is critical to the chemical and thermal balance of the troposphere because, via the formation of hydroxyl radicals, it controls the capacity of tropospheric air to oxidize and remove other pollutants. Moreover, ozone is an important greenhouse gas, particularly in the upper troposphere. Although photochemistry in the lower troposphere is the major source of tropospheric ozone, the stratosphere-troposphere transport of ozone is important to the overall climatology, budget and long-term trends of tropospheric ozone. Stratospheric intrusion events, however, are still poorly understood. Here we introduce the use of modern windprofiler radars to assist in such transport investigations. By hourly monitoring the radar-derived tropopause height in combination with a series of frequent ozonesonde balloon launches, we find numerous intrusions of ozone from the stratosphere into the troposphere in southeastern Canada. On some occasions, ozone is dispersed at altitudes of two to four kilometres, but on other occasions it reaches the ground, where it can dominate the ozone density variability. We observe rapid changes in radar tropopause height immediately preceding these intrusion events. Such changes therefore serve as a valuable diagnostic for the occurrence of ozone intrusion events. Our studies emphasize the impact that stratospheric ozone can have on tropospheric ozone, and show that windprofiler data can be used to infer the possibility of ozone intrusions, as well as better represent tropopause motions in association with stratosphere-troposphere transport.

  15. Polar stratospheric clouds and the ozone hole

    NASA Technical Reports Server (NTRS)

    Hamill, Patrick; Toon, Owen B.

    1991-01-01

    An account is given of physical processes governing the formation of stratospheric particles, in order to dramatize the interactions between polar stratospheric clouds and the Antarctic ozone-destruction mechanism. Attention is given to the successive stages of particle nucleation, condensation/evaporation and sedimentation/coagulation phenomena, and the ways in which polar stratospheric clouds are observed. Considerable evidence exists that polar stratospheric cloud particles are composed of nitric acid. The relatively small Arctic ozone hole depletion is due to the much smaller duration of Arctic stratospheric clouds.

  16. Stratospheric Cooling and Arctic Ozone Recovery

    NASA Technical Reports Server (NTRS)

    Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.

    1998-01-01

    We present sensitivity studies using the AER box model for an idealized parcel in the lower stratosphere at 70 deg N during winter/spring with different assumed stratospheric cooling and chlorine loadings. Our calculations show that stratospheric cooling could further deplete ozone via increased polar stratospheric cloud (PSC) formation and retard its expected recovery even with the projected chlorine loading decrease. We introduce the concept of chlorine-cooling equivalent and show that a 1 K Cooling could provide the same local ozone depletion as an increase of chlorine by 0.4-0.7 ppbv for the scenarios considered. Thus, sustained stratospheric cooling could further reduce Arctic ozone content and delay the anticipated ozone recovery in the Northern Hemisphere even with the realization of the Montreal Protocol and its Amendments.

  17. Stratospheric Cooling and Arctic Ozone Recovery

    NASA Technical Reports Server (NTRS)

    Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.

    1998-01-01

    We present sensitivity studies using the AER( box model for an idealized parcel in the lower stratosphere at 70 N during winter/spring with different assumed stratospheric coolings and chlorine loadings. Our calculations show that stratospheric cooling could further deplete ozone via increased polar stratospheric cloud (PSC) formation and retard its expected recovery even with the projected chlorine loading decrease. We introduce the concept of chlorine-cooling equivalent and show that a 1 K cooling could provide the same local ozone depletion as an increase of chlorine by 0.4-0.7 ppbv for the scenarios considered. Thus, sustained stratospheric cooling could further reduce Arctic ozone content and delay the anticipated ozone recovery in the Northern Hemisphere even with the realization of the Montreal Protocol and its Amendments.

  18. The Chemistry and Physics of Stratospheric Ozone

    NASA Astrophysics Data System (ADS)

    Friedl, Randall R.

    Perhaps no other environmental issue has captured as much widespread public interest and concern as stratospheric ozone depletion due to man-made chlorofluorocarbons (CFCs). Increasing scientific understanding of the connections between CFCs and global-scale ozone changes, highlighted by observations of dramatic ozone loss in the Antarctic, has led to a landmark international treaty and subsequent treaty amendments. As outgrowths of these developments, stratospheric ozone depletion has found its way into science fiction fare and the term “ozone hole” has become part of the English lexicon.

  19. SSTs, nitrogen fertiliser and stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Whitten, R. C.; Poppoff, I. G.; Capone, L. A.

    1978-01-01

    A recently revised model of the stratosphere is used to show that a substantial enhancement in the ozone layer could accompany worldwide SST fleet operations and that water vapor may be an important factor in SST assessments. Revised rate coefficients for various ozone-destroying reactions are employed in calculations which indicate a slight increase in the total content of stratospheric ozone for modest-sized fleets of SSTs flying below about 25 km. It is found that water-vapor chemical reactions can negate in large part the NOx-induced ozone gains computed below 25 km and that increased use of nitrogen fertilizer might also enhance the ozone layer.

  20. Y-12 Plant Stratospheric Ozone Protection plan

    SciTech Connect

    1995-09-01

    The Y-12 Plant staff is required by Lockheed Martin Energy Systems (Energy Systems) (formerly Martin Marietta Energy Systems) standard ESS-EP-129 to develop and implement a Stratospheric Ozone Protection Program which will minimize emissions of ozone-depleting substances to the environment and maximize the use of ozone-safe alternatives in order to comply with Title VI of the 1990 Clean Air Act (CAA) Amendments and the implementing regulations promulgated by the Environmental Protection Agency (EPA). This plan describes the requirements, initiatives, and accomplishments of the Y-12 Plant Stratospheric Ozone Protection Program.

  1. 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.

  2. Forced Planetary Waves, Stratospheric Ozone, and Critical Layers: Ingredients for the Stratospheric Forcing of the Troposphere

    NASA Astrophysics Data System (ADS)

    Nathan, T.; Cordero, E.

    2002-12-01

    Forced planetary waves generally extend throughout the troposphere and stratosphere and thus provide an important link between these two regions of the atmosphere. Because these planetary waves originate from mechanical and thermal forcing in the troposphere, planetary wave energy propagates upward into the stratosphere where momentum deposition via wave damping drives the zonal-mean stratospheric circulation. At the heart of this troposphere-stratosphere paradigm, wherein the troposphere forces the stratosphere, is the momentum deposition associated with the wave damping. Here we present striking evidence showing that the interactions between ozone and the planetary waves not only affects the wave damping rate, but the interactions also produce changes in planetary wave structure and planetary wave fluxes that radiate downward into the troposphere. Using analytical (WKB) and one-dimensional numerical modeling approaches, we show that there is a sensitive and intimate connection among the background flow, ozone, and forced planetary wave field in the stratosphere, a connection that in some cases leads to significant changes in the tropospheric wave fluxes. We find that this connection and thus the stratospheric forcing of the troposphere are dramatically strengthened if the critical level and the maximum in ozone advection are approximately coincident. Such conditions are most often met during Northern Hemisphere spring and summer. We also discuss these results in light of changes in ozone arising from natural (e.g., 11-year solar cycle) and anthropogenic (e.g., chlorofluorocarbons) perturbations.

  3. Longitudinal Variations in Stratospheric Ozone: Effects on "Downward Control"

    NASA Astrophysics Data System (ADS)

    Nathan, T. R.; Cordero, E. C.

    2008-12-01

    The wave drag associated with the damping and breaking of vertically propagating planetary waves in the stratosphere has far-reaching consequences for the global circulation and climate. The planetary wave drag (PWD) exerts non-local control over the extratropical stratosphere that manifests as a wave-driven equator- to-pole meridional circulation, termed the Brewer-Dobson circulation (BDC). In the steady state, the BDC can exert "downward control," whereby the body force exerted by the PWD causes a mean meridional circulation and a simultaneous mass adjustment in the surface pressure. Thus any changes in the PWD in the stratosphere will produce a balanced response in the region below. The downward influence exerted by longitudinal variations in stratospheric ozone is examined using a mechanistic chemistry-dynamical model (CDM) of the extratropical atmosphere. The CDM is one-dimensional in height and self-consistently couples dynamics, radiative transfer, and the transport and photochemistry of ozone. The longitudinal variations in ozone induce a zonal-mean body force that affects the residual circulation via the PWD. Under steady-state conditions, for which the "downward control" principle applies, a WKB analysis yields an analytical expression that shows the direct connection between the residual vertical velocity and the transport and photochemistry of ozone. Because the one-dimensional model framework confines the waves to propagate solely in the vertical, a stratospheric reflecting surface is required for the planetary wave-induced ozone heating in the stratosphere to produce non-local changes in that are manifested in the troposphere. These results underscore the importance of longitudinal variations in ozone as a pathway for communicating, via the combined effects of "downward control" and planetary wave reflection, natural and human-caused changes in stratospheric ozone to changes in tropospheric climate.

  4. Stratospheric Ozone Predictions For The Late 21st Century

    NASA Astrophysics Data System (ADS)

    Douglass, A. R.; Olsen, M. A.; Stolarski, R. S.; Strahan, S. E.; Oman, L.

    2013-12-01

    Simulations of ozone evolution from 1960 until ~2100 from chemistry climate models (CCMs) that participated in CCMVal-2 are broadly consistent in that stratospheric ozone increases as chlorofluorcarbons decrease and the stratosphere cools (which affects the rate of temperature dependent loss processes), however, details of the projections vary significantly. Differences in the ozone response to specified changes in chlorine containing source gases dominate during the first half of the integrations. For example, from 1980 to 2000, chlorine change is by far the most important cause of ozone change, and the CCMs produce changes in the 60S-60N average column ozone that range between -3 DU and -17 DU. In the second half of the 21st century climate change is primarily responsible for ozone change. By 2080 the CCMs produce changes in the 60S-60N average upper stratospheric ozone column that range from 4 DU to 10 DU. The CCM range of differences is due to differences in both composition and upper stratospheric temperature. Ozone loss processes each have their own temperature sensitivity, and the net sensitivity of ozone to temperature change in each CCM depends on the relative importance of each loss process; this depends on the composition and temperature for the baseline atmosphere. In the lower stratosphere, climate change affects ozone evolution through changes in photochemical reaction rates due to stratospheric cooling and through circulation differences affecting transport of ozone and other trace gases. These are not separable using an approach such as multiple linear regression because changes in circulation and temperature have the same time dependence after accounting for contributions due to chlorine change. Recent attention has focused on similarity of the CCMs in that all predict a speed-up of the Brewer Dobson circulation. However, differences in the magnitude of the speed-up, differences in horizontal mixing and differences in the photochemical response to

  5. How do changes in the stratospheric circulation impact ozone?

    NASA Astrophysics Data System (ADS)

    Garny, Hella; Dameris, Martin; Bodeker, Greg; Grewe, Volker; Stenke, Andrea

    2010-05-01

    The Brewer-Dobson circulation (BDC) and tropical upwelling in the lower stratosphere are predicted to increase with increasing greenhouse gas (GHG) concentrations by most climate models and chemistry-climate models (CCMs). This change in the meridional circulation is likely to alter the transport of trace gases, and in particular ozone. In addition, ozone is affected by other processes such as changes in stratospheric temperatures that act to change the reaction rates of ozone-relevant chemistry. These climate-change related modifications of the ozone amount and distribution are superimposed on the depletion and recovery of the ozone layer due to stratospheric halogen loading. To assess the recovery of ozone correctly, it is important to understand the processes that affect ozone in a changing climate. In this study, multiple transient numerical simulations and complementary sensitivity studies with the E39CA CCM are used to disentangle the direct effect of changes in GHG concentrations, the indirect effect of GHG-induced sea surface temperature (SST) changes, and changes in CFC concentrations. It is shown that the increase in tropical upwelling is driven by the changes in SSTs rather than by the direct radiative effect of increased GHG concentrations. Therefore, the sensitivity simulations that separate the direct effect of increased amounts of GHGs and the indirect effect via increased SSTs can be used to separate the impact of the increase in tropical upwelling and the impact of stratospheric cooling on ozone. It is shown that the changes in the meridional circulation cause weak negative trends in the tropical lower stratosphere and associated positive trends in the extra-tropical lower stratosphere. Stratospheric cooling, on the other hand, causes a broad increase in ozone in the stratosphere. To study the processes that lead to changes in the ozone distribution in more detail, different diagnostics that can separate the changes in chemistry (production or

  6. Polar stratospheric clouds and ozone depletion

    SciTech Connect

    Toon, O.B. ); Turco, R.P. )

    1991-06-01

    During the Antarctic winter, strange and often invisible clouds form in the stratosphere over the pole. These clouds of ice and frozen nitric acid play a crucial role in the chemical cycle responsible for the recent appearance of the annual ozone hole. Their chemistry removes compounds that would normally trap ozone-destroying free chlorine produced by the breakdown of CFCs. The paper describes these clouds, their formation, and the mechanisms by which these clouds help chlorine destroy ozone.

  7. Nitrogen fertiliser and stratospheric ozone - Latitudinal effects

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Borucki, W. J.; Capone, L. A.; Riegel, C. A.; Turco, R. P.

    1980-01-01

    Substantial increases in atmospheric N2O resulting from the increased use of nitrogen fertilizers might cause large (to 10%) decreases in the stratospheric ozone content. Such ozone decreases would be caused by catalytic reaction cycles involving odd-nitrogen that is formed by N2O decomposition in the upper stratosphere. Turco et al. (1978), using a background chlorine level of 2 ppbv, have shown that if the measured values of specified reactions are used a 50% increase in N2O would lead to a 2.7% increase in the stratospheric column density, although the ozone content above 30 km would be reduced by more than 5%; they also estimated (unpublished data) that the change in the ozone column density caused by doubling the N2O abundance would be very close to zero (within about 0.1%). The present paper extends these calculations of N2O/ozone effects to two dimensions, thereby identifying the latitude dependence expected for such ozone perturbations. The effects of changes in stratospheric chlorine levels on predicted ozone changes are also discussed.

  8. Climate and Ozone Response to Increased Stratospheric Water Vapor

    NASA Technical Reports Server (NTRS)

    Shindell, Drew T.

    2001-01-01

    Stratospheric water vapor abundance affects ozone, surface climate, and stratospheric temperatures. From 30-50 km altitude, temperatures show global decreases of 3-6 K over recent decades. These may be a proxy for water vapor increases, as the Goddard Institute for Space Studies (GISS) climate model reproduces these trends only when stratospheric water vapor is allowed to increase. Observations suggest that stratospheric water vapor is indeed increasing, however, measurements are extremely limited in either spatial coverage or duration. The model results suggest that the observed changes may be part of a global, long-term trend. Furthermore, the required water vapor change is too large to be accounted for by increased production within the stratosphere, suggesting that ongoing climate change may be altering tropospheric input. The calculated stratospheric water vapor increase contributes an additional approximately equals 24% (approximately equals 0.2 W/m(exp 2)) to the global warming from well-mixed greenhouse gases over the past two decades. Observed ozone depletion is also better reproduced when destruction due to increased water vapor is included. If the trend continues, it could increase future global warming and impede stratospheric ozone recovery.

  9. Arctic "ozone hole" in a cold volcanic stratosphere.

    PubMed

    Tabazadeh, A; Drdla, K; Schoeberl, M R; Hamill, P; Toon, O B

    2002-03-01

    Optical depth records indicate that volcanic aerosols from major eruptions often produce clouds that have greater surface area than typical Arctic polar stratospheric clouds (PSCs). A trajectory cloud-chemistry model is used to study how volcanic aerosols could affect springtime Arctic ozone loss processes, such as chlorine activation and denitrification, in a cold winter within the current range of natural variability. Several studies indicate that severe denitrification can increase Arctic ozone loss by up to 30%. We show large PSC particles that cause denitrification in a nonvolcanic stratosphere cannot efficiently form in a volcanic environment. However, volcanic aerosols, when present at low altitudes, where Arctic PSCs cannot form, can extend the vertical range of chemical ozone loss in the lower stratosphere. Chemical processing on volcanic aerosols over a 10-km altitude range could increase the current levels of springtime column ozone loss by up to 70% independent of denitrification. Climate models predict that the lower stratosphere is cooling as a result of greenhouse gas built-up in the troposphere. The magnitude of column ozone loss calculated here for the 1999--2000 Arctic winter, in an assumed volcanic state, is similar to that projected for a colder future nonvolcanic stratosphere in the 2010 decade.

  10. 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.

  11. The stratospheric ozone layer-an overview.

    PubMed

    Peter, T

    1994-01-01

    This paper summarises the knowledge on the properties of the stratospheric ozone layer. Dynamic, chemical, and microphysical aspects are reviewed with emphasis on chemistry. The questions addressed are as follows. Do we have a quantitative understanding of the Antarctic ozone hole? What lies behind the trend of slowly decreasing ozone columns over northern mid-latitudes? To what degree was chemistry responsible for the extremely low ozone levels over northern Europe in January 1992? The discovery of the ozone hole in 1985 exposed scientific neglect of the category of fast heterogeneous reactions taking place on particulate matter in the stratosphere. But even now after the wide acceptance of some heterogeneous reactions it is difficult to fully account for the rate at which Antarctic ozone is depleted each year in August. After reviewing the known heterogeneous reactions, possible hitherto unrecognised mechanisms are briefly outlined. The paper also includes a discussion of the chemical reactions which can occur even under relatively warm conditions on the ubiquitous, stratospheric aerosol particles and which could contribute to the observed mid-latitudinal ozone depletion. Finally, the paper underlines the importance of dynamic processes, that is, horizontal transport and vertical adiabatic motion, which appear to be the main cause of the anomalously low northern hemispheric ozone values during the 1991/1992 winter.

  12. Intraseasonal oscillations of stratospheric ozone above Switzerland

    NASA Astrophysics Data System (ADS)

    Studer, Simone; Hocke, Klemens; Kämpfer, Niklaus

    2012-01-01

    GROMOS, the ground-based millimeter-wave ozone spectrometer, continuously measures the stratospheric ozone profile between the altitudes of 20 and 65 km above Bern (46°57‧N, 7°27‧E) since November 1994. Characteristics of intraseasonal oscillations of stratospheric ozone are derived from the long-term data set. Spectral analysis gives evidence for a dominant oscillation period of about 20 days in the lower and middle stratosphere during winter time. A strong 20-day wave is also found in collocated geopotential height measurements of the microwave limb sounder onboard the Aura satellite (Aura/MLS) confirming the ground-based observations of GROMOS and underlining the link between ozone and dynamics. Remarkably, the ozone series of GROMOS show an interannual variability of the strength of intraseasonal oscillations of stratospheric ozone. The interannual variability of ozone fluctuations is possibly due to influences of planetary wave forcing and the quasi-biennial oscillation (QBO) on the meridional Brewer-Dobson circulation of the middle atmosphere. In detail, time series of the mean amplitude of ozone fluctuations with periods ranging from 10 to 60 days are derived at fixed pressure levels. The mean amplitude series are regarded as a measure of the strength of intraseasonal oscillations of stratospheric ozone above Bern. After deseasonalizing the mean amplitude series, we find QBO-like amplitude modulations of the intraseasonal oscillations of ozone. The amplitudes of the intraseasonal oscillations are enhanced by a factor of 2 in 1997, 2001, 2003, and 2005. QBO-like variations of intraseasonal oscillations are also present in wind, temperature and other parameters above Bern as indicated by meteorological reanalyses of the European Centre for Medium-range Weather Forecasts (ECMWF). Further, intercomparisons of interannual variability of intraseasonal tropospheric and stratospheric oscillations are performed where the NAO index (North-Atlantic oscillation

  13. High solar cycle spectral variations inconsistent with stratospheric ozone observations

    NASA Astrophysics Data System (ADS)

    Ball, W. T.; Haigh, J. D.; Rozanov, E. V.; Kuchar, A.; Sukhodolov, T.; Tummon, F.; Shapiro, A. V.; Schmutz, W.

    2016-03-01

    Solar variability can influence surface climate, for example by affecting the mid-to-high-latitude surface pressure gradient associated with the North Atlantic Oscillation. One key mechanism behind such an influence is the absorption of solar ultraviolet (UV) radiation by ozone in the tropical stratosphere, a process that modifies temperature and wind patterns and hence wave propagation and atmospheric circulation. The amplitude of UV variability is uncertain, yet it directly affects the magnitude of the climate response: observations from the SOlar Radiation and Climate Experiment (SORCE) satellite show broadband changes up to three times larger than previous measurements. Here we present estimates of the stratospheric ozone variability during the solar cycle. Specifically, we estimate the photolytic response of stratospheric ozone to changes in spectral solar irradiance by calculating the difference between a reference chemistry-climate model simulation of ozone variability driven only by transport (with no changes in solar irradiance) and observations of ozone concentrations. Subtracting the reference from simulations with time-varying irradiance, we can evaluate different data sets of measured and modelled spectral irradiance. We find that at altitudes above pressure levels of 5 hPa, the ozone response to solar variability simulated using the SORCE spectral solar irradiance data are inconsistent with the observations.

  14. STRATOSPHERIC OZONE PROTECTION: AN EPA ENGINEERING PERSPECTIVE

    EPA Science Inventory

    Chlorine released into the atmosphere is a major factor in the depletion of the protective stratospheric ozone layer. The Montreal Protocol, as amended in 1990, and the Clean Air Act Amendments of 1990, address the limits and reduction schedules to be placed on chlorine- and brom...

  15. Stratospheric ozone measurements at the equator

    NASA Technical Reports Server (NTRS)

    Ilyas, Mohammad

    1994-01-01

    A balloon-borne project for ozone layer measurements was undertaken using the MAST ozone sondes and ASTOR radiosondes. Previously published data on this series (Ilyas, 1984) was recently re-analyzed using a rigorous technique to evaluate correction factors (ranging between 1.2 to 1.4). The revised data presented here, show that at the tropospheric and lower stratospheric levels, the ozone concentrations at the equator are much lower than the mid-latitude concentrations. The layer of peak concentration is found to be shifted upward compared to the mid-latitude profile and above this the two profiles get closer.

  16. Predicted aircraft effects on stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Ko, Malcolm K. W.; Wofsy, Steve; Kley, Dieter; Zhadin, Evgeny A.; Johnson, Colin; Weisenstein, Debra; Prather, Michael J.; Wuebbles, Donald J.

    1991-01-01

    The possibility that the current fleet of subsonic aircraft may already have caused detectable changes in both the troposphere and stratosphere has raised concerns about the impact of such operations on stratospheric ozone and climate. Recent interest in the operation of supersonic aircraft in the lower stratosphere has heightened such concerns. Previous assessments of impacts from proposed supersonic aircraft were based mostly on one-dimensional model results although a limited number of multidimensional models were used. In the past 15 years, our understanding of the processes that control the atmospheric concentrations of trace gases has changed dramatically. This better understanding was achieved through accumulation of kinetic data and field observations as well as development of new models. It would be beneficial to start examining the impact of subsonic aircraft to identify opportunities to study and validate the mechanisms that were proposed to explain the ozone responses. The two major concerns are the potential for a decrease in the column abundance of ozone leading to an increase in ultraviolet radiation at the ground, and redistribution of ozone in the lower stratosphere and upper troposphere leading to changes in the Earth's climate. Two-dimensional models were used extensively for ozone assessment studies, with a focus on responses to chlorine perturbations. There are problems specific to the aircraft issues that are not adequately addressed by the current models. This chapter reviews the current status of the research on aircraft impact on ozone with emphasis on immediate model improvements necessary for extending our understanding. The discussion will be limited to current and projected commercial aircraft that are equipped with air-breathing engines using conventional jet fuel. The impacts are discussed in terms of the anticipated fuel use at cruise altitude.

  17. Scientific assessment of stratospheric ozone: 1989, volume 1

    SciTech Connect

    Not Available

    1990-01-01

    A scientific review is presented of the current understanding of stratospheric ozone. There have been highly significant advances in the understanding of the impact of human activities on the Earth's protective ozone layer. There are four major findings that each heighten the concern that chlorine and bromine containing chemicals can lead to a significant depletion of stratospheric ozone: (1) Antarctic ozone hole (the weight of evidence indicates that chlorinated and brominated chemicals are responsible for the ozone hole); (2) Perturbed arctic chemistry (the same potentially ozone destroying processes were identified in the Arctic stratosphere); (3) Long term ozone decreases; and (4) Model limitations (gaps in theoretical models used for assessment studies).

  18. Scientific assessment of stratospheric ozone: 1989, volume 1

    NASA Technical Reports Server (NTRS)

    1990-01-01

    A scientific review is presented of the current understanding of stratospheric ozone. There have been highly significant advances in the understanding of the impact of human activities on the Earth's protective ozone layer. There are four major findings that each heighten the concern that chlorine and bromine containing chemicals can lead to a significant depletion of stratospheric ozone: (1) Antarctic ozone hole (the weight of evidence indicates that chlorinated and brominated chemicals are responsible for the ozone hole; (2) Perturbed arctic chemistry (the same potentially ozone destroying processes were identified in the Arctic stratosphere); (3) Long term ozone decreases; and (4) Model limitations (gaps in theoretical models used for assessment studies).

  19. STROZ LITE - Stratospheric Ozone Lidar Trailer Experiment

    NASA Technical Reports Server (NTRS)

    Mcgee, Thomas J.; Whiteman, David; Ferrare, Richard; Burris, John F.; Butler, James J.

    1991-01-01

    A mobile dual-wavelength differential absorption lidar capable of making precise measurements of stratospheric ozone between 20 and 45 km has been developed at the Goddard Space Flight Center as part of the international Network for the Detection of Stratospheric Change. The system is installed in a 46-ft trailer, which enables the instrument to act as a network transfer standard and to be set up at any location where power can be obtained. A description of the instrument is presented, along with a discussion of the data analysis. Some results from an intercomparison held at JPL's Table Mountain Observatory in California during October and November 1988 are also presented.

  20. 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.

  1. 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.

  2. Energetic particle precipitation: A major driver of the ozone budget in the Antarctic upper stratosphere

    NASA Astrophysics Data System (ADS)

    Damiani, Alessandro; Funke, Bernd; Santee, Michelle L.; Cordero, Raul R.; Watanabe, Shingo

    2016-04-01

    Geomagnetic activity is thought to affect ozone and, possibly, climate in polar regions via energetic particle precipitation (EPP) but observational evidence of its importance in the seasonal stratospheric ozone variation on long time scales is still lacking. Here we fill this gap by showing that at high southern latitudes, late winter ozone series, covering the 1979-2014 period, exhibit an average stratospheric depletion of about 10-15% on a monthly basis caused by EPP. Daily observations indicate that every austral winter EPP-induced low ozone concentrations appear at about 45 km in late June and descend later to 30 km, before disappearing by September. Such stratospheric variations are coupled with mesospheric ozone changes also driven by EPP. No significant correlation between these ozone variations and solar ultraviolet irradiance has been found. This suggests the need of including the EPP forcing in both ozone model simulations and trend analysis.

  3. Ozone density measurements in the troposphere and stratosphere of Natal

    NASA Technical Reports Server (NTRS)

    Kirchhoff, V. W. J. H.; Motta, A. G.

    1983-01-01

    Ozone densitities were measured in the troposphere and stratosphere of Natal using ECC sondes launches on balloons. The data analyzed so far show tropospheric densities and total ozone contents larger than expected.

  4. 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.

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

    SciTech Connect

    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{sub 2}) was converted by reactions on polar stratospheric clouds to reactive ClO and Cl{sub 2}O{sub 2} throughout the Arctic polar vortex before midwinter. Reactive nitrogen was converted to HNO{sub 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.

  6. 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.

  7. Modulations of stratospheric ozone by volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Blanchette, Christian; Mcconnell, John C.

    1994-01-01

    We have used a time series of aerosol surface based on the measurements of Hofmann to investigate the modulation of total column ozone caused by the perturbation to gas phase chemistry by the reaction N2O5(gas) + H2O(aero) yields 2HNO3(gas) on the surface of stratospheric aerosols. We have tested a range of values for its reaction probability, gamma = 0.02, 0.13, and 0.26 which we compared to unperturbed homogeneous chemistry. Our analysis spans a period from Jan. 1974 to Oct. 1994. The results suggest that if lower values of gamma are the norm then we would expect larger ozone losses for highly enhanced aerosol content that for larger values of gamma. The ozone layer is more sensitive to the magnitude of the reaction probability under background conditions than during volcanically active periods. For most conditions, the conversion of NO2 to HNO3 is saturated for reaction probability in the range of laboratory measurements, but is only absolutely saturated following major volcanic eruptions when the heterogeneous loss dominates the losses of N2O5. The ozone loss due to this heterogeneous reaction increases with the increasing chlorine load. Total ozone losses calculated are comparable to ozone losses reported from TOMS and Dobson data.

  8. Impacts of Stratospheric Particles Injection on Stratospheric Ozone: Laboratory Studies

    NASA Astrophysics Data System (ADS)

    Tang, Mingjin; Rkiouak, Laylla; Fuller, Steve; Pope, Francis; Cox, Tony; Watson, Matt; Kalberer, Markus

    2013-04-01

    The stratospheric injection of aerosols is a geoengineering scheme designed to reduce the impacts of climate change. The injected particles scatter solar radiation back to space and hence reduce the radiative forcing of the Earth. The scattering ability of a particle depends on both its size and composition. Particles composed of titania (TiO2) have recently been highlighted as a possible candidate aerosol because of their impressive light scattering ability by virtue of a high refractive index (Pope et al. 2012). The impact of particles injection on stratospheric ozone needs to be systematically assessed via laboratory and modelling studies. In this work, the heterogeneous reactions of airborne TiO2 particles with N2O5 and HCl are investigated by using an atmospheric pressure aerosol flow tube. A Chemical Ionization Mass Spectrometer is used to detect trace gases, and a Scanning Mobility Particle Sizer is used to measure aerosol number concentration and size distribution. The kinetics of the uptake of N2O5 onto TiO2 particles and the influence of HCl will be presented, and the result will be compared to the uptake onto natural sulphate stratospheric particles.

  9. The 2010 Antarctic ozone hole: observed reduction in ozone destruction by minor sudden stratospheric warmings.

    PubMed

    de Laat, A T J; van Weele, M

    2011-01-01

    Satellite observations show that the 2010 Antarctic ozone hole is characterized by anomalously small amounts of photochemical ozone destruction (40-60% less than the 2005-2009 average). Observations from the MLS instrument show that this is mainly related to reduced photochemical ozone destruction between 20-25 km altitude. Lower down between 15-20 km the atmospheric chemical composition and photochemical ozone destruction is unaffected. The modified chemical composition and chemistry between 20-25 km altitude in 2010 is related to the occurrence of a mid-winter minor Antarctic Sudden Stratospheric Warming (SSW). The measurements indicate that the changes in chemical composition are related to downward motion of air masses rather than horizontal mixing, and affect stratospheric chemistry for several months. Since 1979, years with similar anomalously small amounts of ozone destruction are all characterized by either minor or major SSWs, illustrating that their presence has been a necessary pre-condition for reduced Antarctic stratospheric ozone destruction. PMID:22355557

  10. Observational evidence of the influence of Antarctic stratospheric ozone variability on middle atmosphere dynamics

    NASA Astrophysics Data System (ADS)

    Venkateswara Rao, N.; Espy, P. J.; Hibbins, R. E.; Fritts, D. C.; Kavanagh, A. J.

    2015-10-01

    Modeling results have suggested that the circulation of the stratosphere and mesosphere in spring is strongly affected by the perturbations in heating induced by the Antarctic ozone hole. Here using both mesospheric MF radar wind observations from Rothera Antarctica (67°S, 68°W) as well as stratospheric analysis data, we present observational evidence that the stratospheric and mesospheric wind strengths are highly anti-correlated, and show their largest variability in November. We find that these changes are related to the total amount of ozone loss that occurs during the Antarctic spring ozone hole and particularly with the ozone gradients that develop between 57.5°S and 77.5°S. The results show that with increasing ozone loss during spring, winter conditions in the stratosphere and mesosphere persist longer into the summer. These results are discussed in the light of observations of the onset and duration of the Antarctic polar mesospheric cloud season.

  11. Tropospheric and stratospheric ozone from assimilation of Aura data

    NASA Technical Reports Server (NTRS)

    Stajner, I.; Wargan, K.; Chang, L.-P.; Hayashi, H.; Pawwson, S.; Froidevaux, L.; Livesey, N.; Bhartia, P. K.

    2006-01-01

    Ozone is an atmospheric trace gas with multiple impacts on the environment. Global ozone fields are needed for air quality predictions, estimation of the ultraviolet radiation reaching the surface, climate-radiation studies, and may also have an impact on longer-term weather predictions. We estimate global ozone fields in the stratosphere and troposphere by combining the data from EOS Aura satellite with an ozone model using data assimilation. Ozone exhibits a large temporal variability in the lower stratosphere. Our previous work showed that assimilation of satellite data from limb-sounding geometry helps constrain ozone profiles in that region. We assimilated ozone data from the Aura Microwave Limb Sounder (MLS) and the Ozone Monitoring Instrument (OMI) into the ozone system at NASA's Global Modeling and Assimilation Office (GMAO). Ozone is transported within a general circulation model (GCM) which includes parameterizations for stratospheric photochemistry, tropospheric chemistry, and a simple scheme for heterogeneous ozone loss. The focus of this study is on the representation of ozone in the lower stratosphere and tropospheric ozone columns. We plan to extend studies of tropospheric ozone distribution through assimilation of ozone data from the Tropospheric Emission Spectrometer (TES). Comparisons with ozone sondes and occultation data show that assimilation of Aura data reproduces ozone gradients and variability in the lower stratosphere well. We proceed by separating the contributions to temporal changes in the ozone field into those that are due to the model and those that are due to the assimilation of Aura data. The impacts of Aura data are illustrated and their role in the representation of ozone variability in the lower stratosphere and troposphere is shown.

  12. Stratospheric ozone: Impact of human activity

    NASA Astrophysics Data System (ADS)

    McElroy, Michael B.; Salawitch, Ross J.

    1989-12-01

    Current knowledge of the chemistry of the stratosphere is reviewed using measurements from the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment to test the accuracy of our treatment of processes at mid-latitudes, and results from the Airborne Antarctic Ozone Experiment (AAOE) to examine our understanding of processes for the polar environment. It is shown that, except for some difficulties with N 2O 5 and possibly ClNO 3, gas phase models for nitrogen and chlorine species at 30°N in spring are in excellent agreement with the data from ATMOS. Heterogeneous processes may have an influence on the concentrations of NO 2, N 2O 5, HNO 3, and ClNO 3 for the lower stratosphere at 48°S in fall. Comparison of model and observed concentrations of O 3 indicate good agreement at 30°N, with less satisfactory results at 48°S. The discrepancy between the loss rate of O 3 observed over the course of the AAOE mission in 1987 and loss rates calculated using measured concentrations of ClO and BrO is found to be even larger than that reported by Anderson et al. (1989, J. geophys. Res.94, 11480). There appear to be loss processes for removal of O 3 additional to the HOC1 mechanism proposed by Solomon et al. (1986, Nature321, 755), the ClO-BrO scheme favored by McElroy et al. (1986, Nature321, 759), and the ClO dimer mechanism introduced by Molina and Molina (1987, J. phys. Chem.91, 433). There is little doubt that industrial halocarbons have a significant impact on stratospheric O 3. Controls on emissions more stringent than those defined by the Montreal Protocol will be required if the Antarctic Ozone Hole is not to persist as a permanent feature of the stratosphere.

  13. Global variations of zonal mean ozone during stratospheric warming events

    NASA Technical Reports Server (NTRS)

    Randel, William J.

    1993-01-01

    Eight years of Solar Backscatter Ultraviolet (SBUV) ozone data are examined to study zonal mean variations associated with stratospheric planetary wave (warming) events. These fluctuations are found to be nearly global in extent, with relatively large variations in the tropics, and coherent signatures reaching up to 50 deg in the opposite (summer) hemisphere. These ozone variations are a manifestation of the global circulation cells associated with stratospheric warming events; the ozone responds dynamically in the lower stratosphere to transport, and photochemically in the upper stratosphere to the circulation-induced temperature changes. The observed ozone variations in the tropics are of particular interest because transport is dominated by zonal-mean vertical motions (eddy flux divergences and mean meridional transports are negligible), and hence, substantial simplifications to the governing equations occur. The response of the atmosphere to these impulsive circulation changes provides a situation for robust estimates of the ozone-temperature sensitivity in the upper stratosphere.

  14. The ozone hole - The role of polar stratospheric cloud particles

    NASA Technical Reports Server (NTRS)

    Hamill, Patrick; Turco, R. P.

    1988-01-01

    The role of polar stratospheric clouds in the formation of the Antarctic ozone hole is considered. Several researchers have suggested that the decrease in ozone over Antarctica is related to the polar stratospheric clouds (PSCs) which had been observed in the antarctic winter stratosphere. Some of the pertinent characteristics of polar stratospheric clouds are discussed, and it is shown how these clouds may participate in the ozone destruction process. The satellite data for PSCs is analyzed, and statistical information regarding the number and maximum extinctions of these clouds is presented. Evidence that the polar stratospheric clouds are composed of frozen nitric acid is considered. It is suggested that the evaporation of the clouds, in late August and September, will release HOCl and HNO3 to the environment. This could be followed by the photodissociation of HOCl to OH and Cl, which would very effectively destroy ozone. However, the ozone destruction mechanism could be halted when enough of the evaporated nitric acid is photolized.

  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. Stratospheric ozone intercomparison campaign (STOIC) 1989: Overview

    NASA Astrophysics Data System (ADS)

    Margitan, J. J.; Barnes, R. A.; Brothers, G. B.; Butler, J.; Burris, J.; Connor, B. J.; Ferrare, R. A.; Kerr, J. B.; Komhyr, W. D.; McCormick, M. P.; McDermid, I. S.; McElroy, C. T.; McGee, T. J.; Miller, A. J.; Owens, M.; Parrish, A. D.; Parsons, C. L.; Torres, A. L.; Tsou, J. J.; Walsh, T. D.; Whiteman, D.

    1995-05-01

    The NASA Upper Atmosphere Research Program organized a Stratospheric Ozone Intercomparison Campaign (STOIC) held in July-August 1989 at the Table Mountain Facility (TMF) of the Jet Propulsion Laboratory (JPL). The primary instruments participating in this campaign were several that had been developed by NASA for the Network for the Detection of Stratospheric Change: the JPL ozone lidar at TMF, the Goddard Space Flight Center trailer-mounted ozone lidar which was moved to TMF for this comparison, and the Millitech/LaRC microwave radiometer. To assess the performance of these new instruments, a validation/intercomparison campaign was undertaken using established techniques: balloon ozonesondes launched by personnel from the Wallops Flight Facility and from NOAA Geophysical Monitoring for Climate Change (GMCC) (now Climate Monitoring and Diagnostics Laboratory), a NOAA GMCC Dobson spectrophotometer, and a Brewer spectrometer from the Atmospheric Environment Service of Canada, both being used for column as well as Umkehr profile retrievals. All of these instruments were located at TMF and measurements were made as close together in time as possible to minimize atmospheric variability as a factor in the comparisons. Daytime rocket measurements of ozone were made by Wallops Flight Facility personnel using ROCOZ-A instruments launched from San Nicholas Island. The entire campaign was conducted as a blind intercomparison, with the investigators not seeing each others data until all data had been submitted to a referee and archived at the end of the 2-week period (July 20 to August 2, 1989). Satellite data were also obtained from the Stratospheric Aerosol and Gas Experiment (SAGE II) aboard the Earth Radiation Budget Satellite and the total ozone mapping spectrometer (TOMS) aboard Nimbus 7. An examination of the data has found excellent agreement among the techniques, especially in the 20- to 40-km range. As expected, there was little atmospheric variability during the

  17. Stratospheric Ozone Intercomparison Campaign (STOIC) 1989: Overview

    NASA Technical Reports Server (NTRS)

    Margitan, J. J.; Barnes, R. A.; Brothers, G. B.; Butler, J.; Burris, J.; Connor, B. J.; Ferrare, R. A.; Kerr, J. B.; Komhyr, W. D.; McCormick, M. P.; McDermid, I. S.; McElroy, C. T.; McGee, T. J.; Miller, A. J.; Owens, M.; Parrish, A. D.; Parsons, C. L.; Torres, A. L.; Tsou, J. J.; Walsh, T. D.

    1995-01-01

    The NASA Upper Atmosphere Research Program organized a Stratospheric Ozone Intercomparison Campaign (STOIC) held in July-August 1989 at the Table Mountain Facility (TMF) of the Jet Propulsion Laboratory (JPL). The primary instruments participating in this campaign were several that had been developed by NASA for the Network for the Detection of Stratospheric Change: the JPL ozone lidar at TMF, the Goddard Space Flight Center trailer-mounted ozone lidar which was moved to TMF for this comparison, and the Millitech/LaRC microwave radiometer. To assess the performance of these new instruments, a validation/intercomparison campaign was undertaken using established techniques: balloon ozonesondes launched by personnel from the Wallops Flight Facility and from NOAA Geophysical Monitoring for Climate Change (GMCC) (now Climate Monitoring and Diagnostics Laboratory), a NOAA GMCC Dobson spectrophotometer, and a Brewer spectrometer from the Atmospheric Environment Service of Canada, both being used for column as well as Umkehr profile retrievals. All of these instruments were located at TMF and measurements were made as close together in time as possible to minimize atmospheric variability as a factor in the comparisons. Daytime rocket measurements of ozone were made by Wallops Flight Facility personnel using ROCOZ-A instruments launched from San Nicholas Island. The entire campaign was conducted as a blind intercomparison, with the investigators not seeing each others data until all data had been submitted to a referee and archived at the end of the 2-week period (July 20 to August 2, 1989). Satellite data were also obtained from the Stratospheric Aerosol and Gas Experiment (SAGE 2) aboard the Earth Radiation Budget Satellite and the Total Ozone Mapping Spectrometer (TOMS) aboard Nimbus 7. An examination of the data has found excellent agreement among the techniques, especially in the 20- to 40-km range. As expected, there was little atmospheric variability during the

  18. Scientific assessment of stratospheric ozone: 1989, volume 1

    SciTech Connect

    Not Available

    1989-01-01

    A review is presented of the current understanding of stratospheric ozone (SO). The focus is on four major current aspects of SO: (1) polar ozone; (2) global trends; (3) theoretical predictions; and (4) halocarbon ozone depleting materials and global warming potentials. Other ozone related topics are also discussed: (1) the trends of stratospheric temperature, stratospheric aerosols, source gases, and surface ultraviolet radiation; and (2) the oxidizing capacity of the troposphere as it pertains to the lifetimes of ozone related chemicals. There have been highly significant advances in the understanding of the impact of human activities on the Earth's protective ozone layer. There are four major findings that each heighten the concern that chlorine and bromine containing chemicals can lead to a significant depletion of SO: (1) Antarctic Ozone Hole; (2) Perturbed Arctic Chemistry; (3) Long-term Ozone Decreases; and (4) Model Limitations.

  19. Effects of Volcanic Eruptions on Stratospheric Ozone Recovery

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.

    2002-01-01

    The effects of the stratospheric sulfate aerosol layer associated with the Mt. Pinatubo volcano and future volcanic eruptions on the recovery of the ozone layer is studied with an interactive two-dimensional photochemical model. The time varying chlorine loading and the stratospheric cooling due to increasing carbon dioxide have been taken into account. The computed ozone and temperature changes associated with the Mt. Pinatubo eruption in 1991 agree well with observations. Long model runs out to the year 2050 have been carried out, in which volcanoes having the characteristics of the Mount Pinatubo volcano were erupted in the model at 10-year intervals starting in the year 2010. Compared to a non-volcanic run using background aerosol loading, transient reductions of globally averaged column ozone of 2-3 percent were computed as a result of each of these eruptions, with the ozone recovering to that computed for the non-volcanic case in about 5 years after the eruption. Computed springtime Arctic column ozone losses of from 10 to 18 percent also recovered to the non-volcanic case within 5 years. These results suggest that the long-term recovery of ozone would not be strongly affected by infrequent volcanic eruptions with a sulfur loading approximating Mt. Pinatubo. Sensitivity studies in which the Arctic lower stratosphere was forced to be 4 K and 10 K colder resulted in transient ozone losses of which also recovered to the non-volcanic case in 5 years. A case in which a volcano five times Mt. Pinatubo was erupted in the year 2010 led to maximum springtime column ozone losses of 45 percent which took 10 years to recover to the background case. Finally, in order to simulate a situation in which frequent smaller volcanic eruptions result in increasing the background sulfate loading, a simulation was made in which the background aerosol was increased by 10 percent per year. This resulted in a delay of the recovery of column ozone to 1980 values of more than 10 years.

  20. Sensitivity of 21st century stratospheric ozone to greenhouse gas scenarios

    NASA Astrophysics Data System (ADS)

    Eyring, V.; Cionni, I.; Lamarque, J. F.; Akiyoshi, H.; Bodeker, G. E.; Charlton-Perez, A. J.; Frith, S. M.; Gettelman, A.; Kinnison, D. E.; Nakamura, T.; Oman, L. D.; Pawson, S.; Yamashita, Y.

    2010-08-01

    To understand how greenhouse gas (GHG) emissions may affect future stratospheric ozone, 21st century projections from four chemistry-climate models are examined for their dependence on six different GHG scenarios. Compared to higher GHG emissions, lower emissions result in smaller increases in tropical upwelling with resultant smaller reductions in ozone in the tropical lower stratosphere and less severe stratospheric cooling with resultant smaller increases in upper stratospheric ozone globally. Increases in reactive nitrogen and hydrogen that lead to additional chemical ozone destruction mainly play a role in scenarios with higher GHG emissions. Differences among the six GHG scenarios are found to be largest over northern midlatitudes (˜20 DU by 2100) and in the Arctic (˜40 DU by 2100) with divergence mainly in the second half of the 21st century. The uncertainty in the return of stratospheric column ozone to 1980 values arising from different GHG scenarios is comparable to or less than the uncertainty that arises from model differences in the larger set of 17 CCMVal-2 SRES A1B simulations. The results suggest that effects of GHG emissions on future stratospheric ozone should be considered in climate change mitigation policy and ozone projections should be assessed under more than a single GHG scenario.

  1. Influence of an Internally-Generated QBO on Modeled Stratospheric Dynamics and Ozone

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Newman, P. A.; Song, I. S.

    2011-01-01

    A GEOS V2 CCM simulation with an internally generated quasi-biennial oscillation (QBO) signal is compared to an otherwise identical simulation without a QBO. In a present-day climate, inclusion of the modeled QBO makes a significant difference to stratospheric dynamics and ozone throughout the year. The QBO enhances variability in the tropics, as expected, but also in the polar stratosphere in some seasons. The modeled QBO also affects the mean stratospheric climate. Because tropical zonal winds in the baseline simulation are generally easterly, there is a relative increase in zonal wind magnitudes in tropical lower and middle stratosphere in the QBO simulation. Extra-tropical differences between the QBO and 'no QBO' simulations thus reflect a bias toward the westerly phase of the QBO: a relative strengthening and poleward shifting the polar stratospheric jets, and a reduction in Arctic lower stratospheric ozone.

  2. Stratospheric Cooling and Arctic Ozone Recovery. Appendix L

    NASA Technical Reports Server (NTRS)

    Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriguez, Jose M.; Tabazadeh, Azadeh

    1998-01-01

    We present sensitivity studies using the AER box model for an idealized parcel in the lower stratosphere at 70 deg N during winter/spring with different assumed stratospheric cooling and chlorine loadings. Our calculations show that stratospheric cooling could further deplete ozone via increased polar stratospheric cloud (PSC) formation and retard its expected recovery even with the projected chlorine loading decrease. We introduce the concept of chlorine-cooling equivalent and show that a 1 K cooling could provide the same local ozone depletion as an increase of chlorine by 0.4 - 0.7 ppbv for the scenarios considered. Thus, sustained stratospheric cooling could further reduce Arctic ozone content and delay the anticipated ozone recovery in the Northern Hemisphere even with the realization of the Montreal Protocol and its Amendments.

  3. Stratospheric Ozone in the Post-CFC Era

    NASA Technical Reports Server (NTRS)

    Li, Feng; Solarski, Richard S.; Newman, Paul A.

    2008-01-01

    Vertical and latitudinal changes in the stratospheric ozone in the post-chlorofluorocarbon (CFC) era are investigated using simulations of the recent past and the 21st century with a coupled chemistry-climate model. Model results reveal that, in the 2060s when the stratospheric halogen loading is projected to return to its 1980 values, the extratropical column ozone is significantly higher than that in 1975-1984, but the tropical column ozone does not recover to 1980 values. Upper and lower stratospheric ozone changes in the post- CFC era have very different patterns. Above 15 hPa ozone increases almost latitudinally uniformly by 6 Dobson Unit (DU), whereas below 15 hPa ozone decreases in the tropics by 8 DU and increases in the extratropics by up to 16 DU. The upper stratospheric ozone increase is a photochemical response to greenhouse gas induced strong cooling, and the lower stratospheric ozone changes are consistent with enhanced mean advective transport due to a stronger Brewer-Dobson circulation. The model results suggest that the strengthening of the Brewer-Dobson circulation plays a crucial role in ozone recovery and ozone distributions in the post-CFC era.

  4. Stratospheric ozone in the post-CFC era

    NASA Astrophysics Data System (ADS)

    Li, F.; Stolarski, R. S.; Newman, P. A.

    2008-12-01

    Vertical and latitudinal changes in the stratospheric ozone in the post-chlorofluorocarbon (CFC) era are investigated using simulations of the recent past and the 21st century with a coupled chemistry-climate model. Model results reveal that, in the 2060s when the stratospheric halogen loading is projected to return to its 1980 values, the extratropical column ozone is significantly higher than that in 1975-1984, but the tropical column ozone does not recover to 1980 values. Upper and lower stratospheric ozone changes in the post-CFC era have very different patterns. Above 15 hPa ozone increases almost latitudinally uniformly by 6 Dobson Unit (DU), whereas below 15 hPa ozone decreases in the tropics by 8 DU and increases in the extratropics by up to 16 DU. The upper stratospheric ozone increase is a photochemical response to greenhouse gas induced strong cooling, and the lower stratospheric ozone changes are consistent with enhanced mean advective transport due to a stronger Brewer-Dobson circulation. The model results suggest that the strengthening of the Brewer-Dobson circulation plays a crucial role in ozone recovery and ozone distributions in the post-CFC era.

  5. Stratospheric ozone in the post-CFC era

    NASA Astrophysics Data System (ADS)

    Li, F.; Stolarski, R. S.; Newman, P. A.

    2009-03-01

    Vertical and latitudinal changes in the stratospheric ozone in the post-chlorofluorocarbon (CFC) era are investigated using simulations of the recent past and the 21st century with a coupled chemistry-climate model. Model results reveal that, in the 2060s when the stratospheric halogen loading is projected to return to its 1980 values, the extratropical column ozone is significantly higher than that in 1975-1984, but the tropical column ozone does not recover to 1980 values. Upper and lower stratospheric ozone changes in the post-CFC era have very different patterns. Above 15 hPa ozone increases almost latitudinally uniformly by 6 Dobson Unit (DU), whereas below 15 hPa ozone decreases in the tropics by 8 DU and increases in the extratropics by up to 16 DU. The upper stratospheric ozone increase is a photochemical response to greenhouse gas induced strong cooling, and the lower stratospheric ozone changes are consistent with enhanced mean advective transport due to a stronger Brewer-Dobson circulation. The model results suggest that the strengthening of the Brewer-Dobson circulation plays a crucial role in ozone recovery and ozone distributions in the post-CFC era.

  6. Stratospheric Ozone in the Post-CFC Era

    NASA Technical Reports Server (NTRS)

    Li, F.; Stolarski, R. S.; Newman, P. A.

    2009-01-01

    Vertical and latitudinal changes in the stratospheric ozone in the post-chlorofluorocarbon (CFC) era are investigated using simulations of the recent past and the 21st century with a coupled chemistry-climate model. Model results reveal that, in the 2060s when the stratospheric halogen loading is projected to return to its 1980 values, the extratropical column ozone is significantly higher than that in 1975-1984, but the tropical column ozone does not recover to 1980 values. Upper and lower stratospheric ozone changes in the post-CFC era have very different patterns. Above 15 hPa ozone increases almost latitudinally uniformly by 6 Dobson Unit (DU), whereas below 15 hPa ozone decreases in the tropics by 8 DU and increases in the extratropics by up to 16 DU. The upper stratospheric ozone increase is a photochemical response to greenhouse gas induced strong cooling, and the lower stratospheric ozone changes are consistent with enhanced mean advective transport due to a stronger Brewer-Dobson circulation. The model results suggest that the strengthening of the Brewer-Dobson circulation plays a crucial role in ozone recovery and ozone distributions in the post-CFC era.

  7. Understanding differences in chemistry climate model projections of stratospheric ozone

    NASA Astrophysics Data System (ADS)

    Douglass, A. R.; Strahan, S. E.; Oman, L. D.; Stolarski, R. S.

    2014-04-01

    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 ΔO3/ΔCly is a near-linear function of partitioning of total inorganic chlorine (Cly) into its reservoirs; both Cly 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 ΔO3/ΔCly contribute little to the spread in CCM projections as the anthropogenic contribution to Cly becomes unimportant. Differences among upper stratospheric ozone increases due to temperature decreases are explained by differences in ozone sensitivity to temperature change ΔO3/ΔT 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.

  8. Natural and anthropogenic perturbations of the stratospheric ozone layer

    NASA Technical Reports Server (NTRS)

    Brasseur, Guy P.

    1992-01-01

    The paper reviews potential causes for reduction in the ozone abundance. The response of stratospheric ozone to solar activity is discussed. Ozone changes are simulated in relation with the potential development of a fleet of high-speed stratospheric aircraft and the release in the atmosphere of chlorofluorocarbons. The calculations are performed by a two-dimensional chemical-radiative-dynamical model. The importance of heterogeneous chemistry in polar stratospheric clouds and in the Junge layer (sulfate aerosol) is emphasized. The recently reported ozone trend over the last decade is shown to have been largely caused by the simultaneous effects of increasing concentrations of chlorofluorocarbons and heterogeneous chemistry. The possibility for a reduction in stratospheric ozone following a large volcanic eruption such as that of Mount Pinatubo in 1991 is discussed.

  9. Mass and Ozone Fluxes from the Lowermost Stratosphere

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.; Olsen, Mark A.

    2004-01-01

    Net mass flux from the stratosphere to the troposphere can be computed from the heating rate along the 380K isentropic surface and the time rate of change of the mass of the lowermost stratosphere (the region between the tropopause and the 380K isentrope). Given this net mass flux and the cross tropopause diabatic mass flux, the residual adiabatic mass flux across the tropopause can also be estimated. These fluxes have been computed using meteorological fields from a free-running general circulation model (FVGCM) and two assimilation data sets, FVDAS, and UKMO. The data sets tend to agree that the annual average net mass flux for the Northern Hemisphere is about 1P10 kg/s. There is less agreement on the southern Hemisphere flux that might be half as large. For all three data sets, the adiabatic mass flux is computed to be from the upper troposphere into the lowermost stratosphere. This flux will dilute air entering from higher stratospheric altitudes. The mass fluxes are convolved with ozone mixing ratios from the Goddard 3D CTM (which uses the FVGCM) to estimate the cross-tropopause transport of ozone. A relatively large adiabatic flux of tropospheric ozone from the tropical upper troposphere into the extratropical lowermost stratosphere dilutes the stratospheric air in the lowermost stratosphere. Thus, a significant fraction of any measured ozone STE may not be ozone produced in the higher Stratosphere. The results also illustrate that the annual cycle of ozone concentration in the lowermost stratosphere has as much of a role as the transport in the seasonal ozone flux cycle. This implies that a simplified calculation of ozone STE mass from air mass and a mean ozone mixing ratio may have a large uncertainty.

  10. Quantifying isentropic stratosphere-troposphere exchange of ozone

    NASA Astrophysics Data System (ADS)

    Yang, Huang; Chen, Gang; Tang, Qi; Hess, Peter

    2016-04-01

    There is increased evidence that stratosphere-troposphere exchange (STE) of ozone has a significant impact on tropospheric chemistry and radiation. Traditional diagnostics of STE consider the ozone budget in the lowermost stratosphere (LMS) as a whole. However, this can only render the hemispherically integrated ozone flux and therefore does not distinguish the exchange of ozone into low latitudes from that into high latitudes. The exchange of ozone at different latitudes may have different tropospheric impacts. This present study extends the traditional approach from the entire LMS to individual isentropic layers in the LMS and therefore gives the meridional distribution of STE by the latitudes where each isentropic surface intersects the tropopause. The specified dynamics version of the Whole Atmosphere Community Climate Model is used to estimate the STE ozone flux on each isentropic surface. It is found that net troposphere-to-stratosphere ozone transport occurs in low latitudes along the 350-380 K isentropic surfaces and that net stratosphere-to-troposphere ozone transport takes place in the extratropics along the 280-350 K isentropes. Particularly, the seasonal cycle of extratropical STE ozone flux in the Northern Hemisphere displays a maximum in late spring and early summer, following the seasonal migration of the upper tropospheric jet and associated isentropic mixing. Furthermore, differential diabatic heating and isentropic mixing tend to induce STE ozone fluxes in opposite directions, but the net effect results in a spatiotemporal pattern similar to the STE ozone flux associated with isentropic mixing.

  11. The Interdecadal Pacific Oscillation and mid-stratospheric tropical ozone trends

    NASA Astrophysics Data System (ADS)

    Iglesias-Suarez, Fernando; Young, Paul J.; Wild, Oliver; Kinnison, Douglas E.

    2016-04-01

    In recent years, the global ozone layer has started to show the first signs of recovery, but puzzlingly tropical mid-stratospheric ozone has decreased since the beginning of the 90s. This is a key region of the stratosphere where most ozone is produced. Previous studies have shown that interannual variability in the troposphere (e.g. El Nino-Southern Oscillation) can affect the lower stratosphere, both dynamics and composition. Here for the first time, we show how multidecadal internal climate variability - in the Pacific Ocean's sea surface temperatures (i.e. the Interdecadal Pacific Oscillation, IPO) - have an impact in mid-stratospheric tropical ozone, and account for the observed trends. We suggest a mechanism that involves dynamical (i.e. Brewer Dobson circulation) and chemical (i.e. ozone loss chemistry via NOy chemistry) processes to explain this IPO-ozone link. Understanding internally generated multidecadal variability in this region of the stratosphere is crucial to distinguish between forced and unforced signals and better describe ozone recovery.

  12. Attribution of Recovery in Lower-stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Yang, Eun-Su; Cunnold, Derek M.; Salawitch, Ross J.; McCormick, M. Patrick; Russell, James, III; Zawodny, Joseph M.; Oltmans, Samuel; Newchurch, Michael J.

    2006-01-01

    Multiple satellite and ground-based observations provide consistent evidence that the thickness of Earth's protective ozone layer has stopped declining since 1997, close to the time of peak stratospheric halogen loading. Regression analyses with Effective Equivalent Stratospheric Chlorine (EESC) in conjunction with further analyses using more sophisticated photochemical model calculations constrained by satellite data demonstrate that the cessation of ozone depletion between 18-25 km altitude is consistent with a leveling off of stratospheric abundances of chlorine and bromine, due to the Montreal Protocol and its amendments. However, ozone increases in the lowest part of the stratosphere, from the tropopause to 18 km, account for about half of the improvement in total column ozone during the past 9 years at northern hemisphere mid-latitudes. The increase in ozone for altitudes below 18 km is most likely driven by changes in transport, rather than driven by declining chlorine and bromine. Even with this evidence that the Montreal Protocol and its amendments are having the desired, positive effect on ozone above 18 km, total column ozone is recovering faster than expected due to the apparent transport driven changes at lower altitudes. Accurate prediction of future levels of stratospheric ozone will require comprehensive understanding of the factors that drive temporal changes at various altitudes, and partitioning of the recent transport-driven increases between natural variability and changes in atmospheric structure perhaps related to anthropogenic climate change.

  13. The impact of polar stratospheric ozone loss on Southern Hemisphere stratospheric circulation and climate

    NASA Astrophysics Data System (ADS)

    Keeble, J.; Braesicke, P.; Abraham, N. L.; Roscoe, H. K.; Pyle, J. A.

    2014-12-01

    The impact of polar stratospheric ozone loss resulting from chlorine activation on polar stratospheric clouds is examined using a pair of model integrations run with the fully coupled chemistry climate model UM-UKCA. Suppressing chlorine activation through heterogeneous reactions is found to produce modelled ozone differences consistent with observed ozone differences between the present and pre-ozone hole period. Statistically significant high-latitude Southern Hemisphere (SH) ozone loss begins in August and peaks in October-November, with > 75% of ozone destroyed at 50 hPa. Associated with this ozone destruction is a > 12 K decrease of the lower polar stratospheric temperatures and an increase of > 6 K in the upper stratosphere. The heating components of this temperature change are diagnosed and it is found that the temperature dipole is the result of decreased short-wave heating in the lower stratosphere and increased dynamical heating in the upper stratosphere. The cooling of the polar lower stratosphere leads, through thermal wind balance, to an acceleration of the polar vortex and delays its breakdown by ~ 2 weeks. A link between lower stratospheric zonal wind speed, the vertical component of the Eliassen-Palm (EP) flux, Fz and the residual mean vertical circulation, w*, is identified. In November and December, increased westerly winds and a delay in the breakup of the polar vortex lead to increases in Fz, indicating increased wave activity entering the stratosphere and propagating to higher altitudes. The resulting increase in wave breaking, diagnosed by decreases to the EP flux divergence, drives enhanced downwelling over the polar cap. Many of the stratospheric signals modelled in this study propagate down to the troposphere, and lead to significant surface changes in December.

  14. Multi-model assessment of stratospheric ozone return dates and ozone recovery in CCMVal-2 models

    NASA Astrophysics Data System (ADS)

    Eyring, V.; Cionni, I.; Bodeker, G. E.; Charlton-Perez, A. J.; Kinnison, D. E.; Scinocca, J. F.; Waugh, D. W.; Akiyoshi, H.; Bekki, S.; Chipperfield, M. P.; Dameris, M.; Dhomse, S.; Frith, S. M.; Garny, H.; Gettelman, A.; Kubin, A.; Langematz, U.; Mancini, E.; Marchand, M.; Nakamura, T.; Oman, L. D.; Pawson, S.; Pitari, G.; Plummer, D. A.; Rozanov, E.; Shepherd, T. G.; Shibata, K.; Tian, W.; Braesicke, P.; Hardiman, S. C.; Lamarque, J. F.; Morgenstern, O.; Pyle, J. A.; Smale, D.; Yamashita, Y.

    2010-10-01

    Projections of stratospheric ozone from a suite of chemistry-climate models (CCMs) have been analyzed. In addition to a reference simulation where anthropogenic halogenated ozone depleting substances (ODSs) and greenhouse gases (GHGs) vary with time, sensitivity simulations with either ODS or GHG concentrations fixed at 1960 levels were performed to disaggregate the drivers of projected ozone changes. These simulations were also used to assess the two distinct milestones of ozone returning to historical values (ozone return dates) and ozone no longer being influenced by ODSs (full ozone recovery). The date of ozone returning to historical values does not indicate complete recovery from ODSs in most cases, because GHG-induced changes accelerate or decelerate ozone changes in many regions. In the upper stratosphere where CO2-induced stratospheric cooling increases ozone, full ozone recovery is projected to not likely have occurred by 2100 even though ozone returns to its 1980 or even 1960 levels well before (~2025 and 2040, respectively). In contrast, in the tropical lower stratosphere ozone decreases continuously from 1960 to 2100 due to projected increases in tropical upwelling, while by around 2040 it is already very likely that full recovery from the effects of ODSs has occurred, although ODS concentrations are still elevated by this date. In the midlatitude lower stratosphere the evolution differs from that in the tropics, and rather than a steady decrease in ozone, first a decrease in ozone is simulated from 1960 to 2000, which is then followed by a steady increase through the 21st century. Ozone in the midlatitude lower stratosphere returns to 1980 levels by ~2045 in the Northern Hemisphere (NH) and by ~2055 in the Southern Hemisphere (SH), and full ozone recovery is likely reached by 2100 in both hemispheres. Overall, in all regions except the tropical lower stratosphere, full ozone recovery from ODSs occurs significantly later than the return of total column

  15. 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.

  16. On the surface impact of Arctic stratospheric ozone extremes

    NASA Astrophysics Data System (ADS)

    Calvo, N.; Polvani, L. M.; Solomon, S.

    2015-09-01

    A comprehensive stratosphere-resolving atmospheric model, with interactive stratospheric ozone chemistry, coupled to ocean, sea ice and land components is used to explore the tropospheric and surface impacts of large springtime ozone anomalies in the Arctic stratosphere. Coupling between the Antarctic ozone hole and Southern Hemisphere climate has been identified in numerous studies, but connections of Arctic ozone loss to surface climate have been more difficult to elucidate. Analyzing an ensemble of historical integrations with all known natural and anthropogenic forcings specified over the period 1955-2005, we find that extremely low stratospheric ozone changes are able to produce large and robust anomalies in tropospheric wind, temperature and precipitation in April and May over large portions of the Northern Hemisphere (most notably over the North Atlantic and Eurasia). Further, these ozone-induced surface anomalies are obtained only in the last two decades of the 20th century, when high concentrations of ozone depleting substances generate sufficiently strong stratospheric temperature anomalies to impact the surface climate. Our findings suggest that coupling between chemistry and dynamics is essential for a complete representation of surface climate variability and climate change not only in Antarctica but also in the Arctic.

  17. The impact of polar stratospheric ozone loss on Southern Hemisphere stratospheric circulation and climate

    NASA Astrophysics Data System (ADS)

    Keeble, J.; Braesicke, P.; Abraham, N. L.; Roscoe, H. K.; Pyle, J. A.

    2014-07-01

    The impact of polar stratospheric ozone loss resulting from chlorine activation on polar stratospheric clouds is examined using a pair of model integrations run with the fully coupled chemistry climate model UM-UKCA. Suppressing chlorine activation through heterogeneous reactions is found to produce modelled ozone differences consistent with observed ozone differences between the present and pre-ozone hole period. Statistically significant high latitude Southern Hemisphere (SH) ozone loss begins in August and peaks in October-November, with >75% of ozone destroyed at 50 hPa. Associated with this ozone destruction is a >12 K decrease of the lower polar stratospheric temperatures and an increase of >6 K in the upper stratosphere. The heating components of this temperature change are diagnosed and it is found that the temperature dipole is the result of decreased shortwave heating in the lower stratosphere and increased dynamical heating in the upper stratosphere. The cooling of the polar lower stratosphere leads, through thermal wind balance, to an acceleration of the polar vortex and delays its breakdown by ~2 weeks. A link between lower stratospheric zonal wind speed, the vertical component of the EP flux, Fz, and the residual mean vertical circulation, w*, is identified. In December and January, increased westerly winds lead to increases in Fz, associated with an increase in tropopause height. The resulting increase in wavebreaking leads to enhanced downwelling/reduced upwelling over the polar cap. Many of the stratospheric signals modelled in this study propagate down to the troposphere, and lead to significant surface changes in December.

  18. Examination of stratospheric ozone photochemistry in light of recent data

    NASA Technical Reports Server (NTRS)

    Natarajan, Murali; Callis, Linwood B.

    1989-01-01

    The consistency of stratospheric ozone photochemistry is examined using data from the Atmospheric Trace Molecule Spectroscopy (ATMOS) and LIMS experiments. The ATMOS experiment measured vertical profiles of important trace constituents and temperature in the stratosphere during 1985. These observations have been used to constrain the levels of odd nitrogen and odd chlorine in a photochemical model. This model yields O3 mixing ratios that are in good agreement with the observations. The deviation in ozone is less than 20 percent except near 52 km. The updated model has also been used in conjunction with the LIMS data to simulate the stratospheric photochemistry corresponding to the 1979 time period.

  19. Fluorine photochemistry in the stratosphere. [effect on ozone

    NASA Technical Reports Server (NTRS)

    Stolarski, R. S.; Rundel, R. D.

    1975-01-01

    The photochemistry of fluorine in the stratosphere is surveyed in order to estimate the effect on ozone of fluorine atoms released by the breakdown of chlorofluoromethanes. The catalytic efficiency for ozone destruction by fluorine is found to be less than .0001 that of chlorine in the altitude range from 25 to 50 km.

  20. Stratospheric ozone variations in the equatorial region as seen in Stratospheric and Gas Experiment data

    SciTech Connect

    Masato Shiotani; Fumio Hasebe

    1994-07-20

    An analysis is made of equatorial ozone variations for 5 years, 1984-1989, using the ozone profile data derived from the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument. Attention is focused on the annual cycle and also on interannual variability, particularly the quasi-biennial oscillation (QBO) and El Nino-Southern Oscillation (ENSO) variations in the lower stratosphere, where the largest contribution to total column ozone takes place. The annual variation in zonal mean total ozone around the equator is composed of symmetric and asymmetric modes with respect to the equator, with maximum contributions being around 19 km for the symmetric mode and around 25 km for the asymmetric mode. The persistent zonal wavenumber 1 structure observed by the total ozone mapping spectrometer over the equator is almost missing in the SAGE-derived column amounts integrated in the stratosphere, suggesting a significant contribution from tropospheric ozone. Interannual variations in the equatorial ozone are dominated by the QBO above 20 km and the ENSO-related variation below 20 km. The ozone QBO is characterized by zonally uniform phase changes in association with the zonal wind QBO in the equatorial lower stratosphere. The ENSO-related ozone variation consists of both the east-west vacillation and the zonally uniform phase variation. During the El Nino event, the east-west contrast with positive (negative) deviations in the eastern (western) hemisphere is conspicuous, while the decreasing tendency of the zonal mean values is maximum at the same time. 28 refs., 13 figs.

  1. Multi-model assessment of stratospheric ozone return dates and ozone recovery in CCMVal-2 models

    NASA Astrophysics Data System (ADS)

    Eyring, V.; Cionni, I.; Bodeker, G. E.; Charlton-Perez, A. J.; Kinnison, D. E.; Scinocca, J. F.; Waugh, D. W.; Akiyoshi, H.; Bekki, S.; Chipperfield, M. P.; Dameris, M.; Dhomse, S.; Frith, S. M.; Garny, H.; Gettelman, A.; Kubin, A.; Langematz, U.; Mancini, E.; Marchand, M.; Nakamura, T.; Oman, L. D.; Pawson, S.; Pitari, G.; Plummer, D. A.; Rozanov, E.; Shepherd, T. G.; Shibata, K.; Tian, W.; Braesicke, P.; Hardiman, S. C.; Lamarque, J. F.; Morgenstern, O.; Pyle, J. A.; Smale, D.; Yamashita, Y.

    2010-05-01

    Projections of stratospheric ozone from a suite of chemistry-climate models (CCMs) have been analyzed. In addition to a reference simulation where anthropogenic halogenated ozone depleting substances (ODSs) and greenhouse gases (GHGs) vary with time, sensitivity simulations with either ODSs or GHGs concentrations fixed at 1960 levels were performed to disaggregate the drivers of projected ozone changes. These simulations were also used to assess the two distinct milestones of ozone returning to historical values (ozone return dates) and ozone no longer being influenced by ODSs (full ozone recovery). These two milestones are different. The date of ozone returning to historical values does not indicate complete recovery from ODSs in most cases, because GHG induced changes accelerate or decelerate ozone changes in many regions. In the upper stratosphere where GHG induced stratospheric cooling increases ozone, full ozone recovery has not likely occurred by 2100 while ozone returns to its 1980 or even 1960 levels well before (~2025 and 2040, respectively). In contrast, in the tropical lower stratosphere ozone decreases continuously from 1960 to 2100 due to projected increases in tropical upwelling, while by around 2040 it is already very likely that full recovery from the effects of ODSs has occurred, although ODS concentrations are still elevated by this date. In the lower midlatitude stratosphere the evolution differs from that in the tropics, and rather than a steady decrease of ozone, first a decrease of ozone is simulated between 1960 and 2000, which is then followed by a steady increase throughout the 21st century. Ozone in the lower stratosphere midlatitudes returns to its 1980 levels ˜2045 in the NH and ~2055 in the SH, and full ozone recovery is likely reached by 2100 in both hemispheres. Overall, in all regions except the tropical lower stratosphere, full ozone recovery from ODSs occurs significantly later than the return of total column ozone to its 1980

  2. Impact of stratospheric changes on past and future tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Lang, C.; Waugh, D. W.; Olsen, M. A.; Douglass, A. R.; Duncan, B. N.; Liang, Q.; Nielsen, J. E.; Oman, L. D.; Pawson, S.; Stolarski, R. S.

    2011-12-01

    A new version of the Goddard Earth Observing System chemistry-climate model (GEOS CCM) with a combined troposphere-stratospheric chemical mechanism is used to examine the impact of stratospheric changes on the evolution of tropospheric ozone. Time-slice integrations were performed for 1960, 2005 and 2100. These simulations differ in values of prescribed ozone depleting substances (ODSs), greenhouse gases (GHGs) and sea-surface temperatures (SSTs). The past decline and projected future recovery in stratospheric ozone lead that the influx of stratospheric ozone into the troposphere decreased between 1960 and 2005 and increases between 2005 and 2100. An increase in mass transport into the troposphere, due primarily to increases in GHGs and SSTs, further enhances the stratospheric contribution in the future. The net stratospheric impact in the past is the largest in the southern extratropics (10-15% decrease in tropospheric burden and surface ozone, compared to 1-3% decrease in northern hemisphere). However, for the scenario considered, the impact in the future is similar in both hemispheres (~10-15% increase in tropospheric burden).

  3. 77 FR 58081 - Protection of Stratospheric Ozone: Listing of Substitutes for Ozone-Depleting Substances-Fire...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-19

    ... because their emissions into the atmosphere are highly destructive to the stratospheric ozone layer. This... would assist in restoring the stratospheric ozone layer, avoiding adverse climate impacts, and result in... AGENCY 40 CFR Part 82 RIN-2060-AQ84 Protection of Stratospheric Ozone: Listing of Substitutes for...

  4. Role of Methane in Antarctic Stratospheric Ozone Recovery

    NASA Astrophysics Data System (ADS)

    Calvo, Natalia; Kinnison, Douglas E.; Marsh, Daniel R.; Garcia, Rolando R.; Palmeiro, Froila

    2014-05-01

    Observational and modeling studies have shown the impact of changes in Antarctic stratospheric ozone on tropospheric climate in austral spring and summer. In the future, effects of increasing greenhouse gases and ozone depleting substances oppose each other. Projections show potential impact of ozone recovery on precipitation, carbon uptake in the Southern Hemisphere ocean, Antarctic ice sheets and Southern Hemisphere sea ice. In order to quantify properly the tropospheric impacts of ozone recovery, future Antarctic ozone changes in the upper troposphere lower stratosphere region and the role (if any) of increasing greenhouse gases in ozone recovery need to be evaluated. To do so, we use the National Center for Atmospheric Research's Community Earth System Model, CESM, with the high-top version of the atmospheric component, CESM(WACCM), which is a fully coupled chemistry climate model. Three climate change scenarios (RCP2.6, RCP4.5 and RCP8.5) of 3 simulations each from 2005 to 2065 are analyzed. In scenario RCP2.6, the largest ozone recovery is simulated in October and November at 50hPa and it is followed by the largest response in temperature in November and December at 70hPa. While the response in RCP4.5 in ozone and temperature is almost identical to that in RCP2.6 in the upper troposphere and lower stratosphere region, scenario RCP8.5 shows significantly stronger ozone recovery and warming than the other two scenarios, particularly in November and December at 70hPa in ozone and 100hPa in temperature. We show that this is due to larger amounts of methane in RCP8.5 compared to the other two scenarios, which reduces catalytic ozone loss locally. Differences across scenarios in advection of ozone from the source region in the tropical stratosphere do not play a significant role.

  5. An Ozone Increase in the Antarctic Summer Stratosphere: A Dynamical Response to the Ozone Hole

    NASA Technical Reports Server (NTRS)

    Stolarski, R. S.; Douglass, A. R.; Gupta, M.; Newman, P. A.; Pawson, S.; Schoeberl, M. R.; Nielsen, J. E.

    2007-01-01

    Profiles of ozone concentration retrieved from the SBUV series of satellites show an increase between 1979 and 1997 in the summertime Antarctic middle stratosphere (approx. 25-10 hPa). Data over the South Pole from ozone sondes confirm the increase. A similar ozone increase is produced in a chemistry climate model that allows feedback between constituent changes and the stratospheric circulation through radiative heating. A simulation that excludes the radiative coupling between predicted ozone and the circulation does not capture this ozone increase. We show that the ozone increase in our model simulations is caused by a dynamical feedback in response to the changes in the stratospheric wind fields forced by the radiative perturbation associated with the Antarctic ozone hole.

  6. Evidence for slowdown in stratospheric ozone loss: First stage of ozone recovery

    NASA Technical Reports Server (NTRS)

    Newchurch, M. J.; Yang, Eun-Su; Cunnold, D. M.; Reinsel, C.; Zawodny, J. M.; Russell, James M., III

    2003-01-01

    Global ozone trends derived from the Stratospheric Aerosol and Gas Experiment I and II (SAGE I/II) combined with the more recent Halogen Occultation Experiment (HALOE) observations provide evidence of a slowdown in stratospheric ozone losses since 1997. This evidence is quantified by the cumulative sum of residual differences from the predicted linear trend. The cumulative residuals indicate that the rate of ozone loss at 35- 45 km altitudes globally has diminished. These changes in loss rates are consistent with the slowdown of total stratospheric chlorine increases characterized by HALOE HCI measurements. These changes in the ozone loss rates in the upper stratosphere are significant and constitute the first stage of a recovery of the ozone layer.

  7. Impact of Stratospheric Ozone Distribution on Features of Tropospheric Circulation

    NASA Astrophysics Data System (ADS)

    Barodka, Siarhei; Krasouski, Aliaksandr; Mitskevich, Yaroslav; Shalamyansky, Arkady

    2016-04-01

    In this work we study connections between stratospheric ozone distribution and general circulation patterns in the troposphere and aim to investigate the causal relationship between them, including the practical side of the influence of stratospheric ozone on tropospheric medium-range weather and regional climate. Analysis of several decades of observational data, which has been performed at the A.I. Voeikov Main Geophysical Observatory, suggests a clear relation between the stratospheric ozone distribution, upper stratospheric temperature field and planetary-scale air-masses boundaries in the troposphere [1]. Furthermore, it has been shown that each global air-mass, which can be attributed to the corresponding circulation cell in a conceptual model of tropospheric general circulation, has a distinct "regime" of ozone vertical distribution in the stratosphere [1-3]. Proceeding from atmospheric reanalyses combined with satellite and ground-based observations, we study time evolution of the upper-level frontal zones (stationary fronts) with the relevant jet streams, which can be treated as boundaries of global air-masses, in connection with the tropopause height and distribution of ozone in the stratosphere. For that, we develop an algorithm for automated identification of jet streams, stationary fronts and tropopause surface from gridded data (reanalyses or modelling results), and apply it for several cases associated with rapid changes in the stratospheric temperature and ozone fields, including SSW events over Eastern Siberia. Aiming to study the causal relationship between the features of tropospheric circulation and changes in the stratospheric ozone field, we estimate the time lag between these categories of processes on different time scales. Finally, we discuss the possibility to use the elementary circulation mechanisms classification (by B.L. Dzerdzeevski) in connection with analysis of the stratospheric ozone field and the relevant stratosphere

  8. The impact of the stratospheric ozone distribution on large-scale tropospheric systems over South America

    NASA Astrophysics Data System (ADS)

    Da Silva, L. A.; Vieira, L. A.; Prestes, A.; Pacini, A. A.; Rigozo, N. R.

    2013-12-01

    Most of the large-scale changes of the climate can be attributed to the cumulative impact of the human activities since the beginning of the industrial revolution. However, the impact of natural drivers to the present climate change is still under debate, especially on regional scale. These regional changes over South America can potentially affect large vulnerable populations in the near future. Here, we show that the distribution of the stratospheric ozone can affect the climate patterns over South America and adjoin oceans. The impact of the stratospheric ozone distribution was evaluated employing the Global Atmospheric-Ocean Model developed by the Goddard Institute for Space Studies (GISS Model E). We conducted two numerical experiments. In the first experiment we used a realistic distribution of the stratospheric ozone, while in the second experiment we employed a uniform longitudinal distribution. We have integrated each model over 60 years. We find that the distribution of stratospheric ozone has a strong influence on the Intertropical Convergence Zone (ITCZ) and South Atlantic Convergence Zone (SACZ). However, the Upper Tropospheric Cyclonic Vortex (UTCV) is not affected by the ozone's distribution.

  9. Multimodel projections of stratospheric ozone in the 21st century

    NASA Astrophysics Data System (ADS)

    Eyring, V.; Waugh, D. W.; Bodeker, G. E.; Cordero, E.; Akiyoshi, H.; Austin, J.; Beagley, S. R.; Boville, B. A.; Braesicke, P.; Brühl, C.; Butchart, N.; Chipperfield, M. P.; Dameris, M.; Deckert, R.; Deushi, M.; Frith, S. M.; Garcia, R. R.; Gettelman, A.; Giorgetta, M. A.; Kinnison, D. E.; Mancini, E.; Manzini, E.; Marsh, D. R.; Matthes, S.; Nagashima, T.; Newman, P. A.; Nielsen, J. E.; Pawson, S.; Pitari, G.; Plummer, D. A.; Rozanov, E.; Schraner, M.; Scinocca, J. F.; Semeniuk, K.; Shepherd, T. G.; Shibata, K.; Steil, B.; Stolarski, R. S.; Tian, W.; Yoshiki, M.

    2007-08-01

    Simulations from eleven coupled chemistry-climate models (CCMs) employing nearly identical forcings have been used to project the evolution of stratospheric ozone throughout the 21st century. The model-to-model agreement in projected temperature trends is good, and all CCMs predict continued, global mean cooling of the stratosphere over the next 5 decades, increasing from around 0.25 K/decade at 50 hPa to around 1 K/decade at 1 hPa under the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario. In general, the simulated ozone evolution is mainly determined by decreases in halogen concentrations and continued cooling of the global stratosphere due to increases in greenhouse gases (GHGs). Column ozone is projected to increase as stratospheric halogen concentrations return to 1980s levels. Because of ozone increases in the middle and upper stratosphere due to GHG-induced cooling, total ozone averaged over midlatitudes, outside the polar regions, and globally, is projected to increase to 1980 values between 2035 and 2050 and before lower-stratospheric halogen amounts decrease to 1980 values. In the polar regions the CCMs simulate small temperature trends in the first and second half of the 21st century in midwinter. Differences in stratospheric inorganic chlorine (Cly) among the CCMs are key to diagnosing the intermodel differences in simulated ozone recovery, in particular in the Antarctic. It is found that there are substantial quantitative differences in the simulated Cly, with the October mean Antarctic Cly peak value varying from less than 2 ppb to over 3.5 ppb in the CCMs, and the date at which the Cly returns to 1980 values varying from before 2030 to after 2050. There is a similar variation in the timing of recovery of Antarctic springtime column ozone back to 1980 values. As most models underestimate peak Cly near 2000, ozone recovery in the Antarctic could occur even later, between 2060 and 2070. In the

  10. Polar stratospheric ozone: interactions with climate change, results from the EU project RECONCILE, and the 2010/11 Arctic ozone hole

    NASA Astrophysics Data System (ADS)

    von Hobe, Marc

    2013-04-01

    One of the most profound and well known examples of human impacts on atmospheric chemistry is the so called ozone hole. During the second half of the 20th century, anthropogenic emissions of chlorofluorocarbons (CFCs) led to a significant increase in stratospheric chlorine levels and hence the rate of ozone removal by catalytic cycles involving chlorine. While CFCs were essentially banned by the 1987 Montreal Protocol and its subsequent amendments, and stratospheric chlorine levels have recently started to decline again, another anthropogenic influence may at least delay the recovery of the stratospheric ozone layer: climate change, with little doubt a result of human emissions of carbon dioxide and other greenhouse gases, has led to changes in stratospheric temperature and circulation. The large ozone losses that typically occur in polar regions in spring are particularly affected by these changes. Here, we give an overview of the ozone-climate interactions affecting polar stratospheric ozone loss, and present latest results from the international research project RECONCILE funded by the European Commission. Remaining open questions will be discussed including the possible impacts of recently suggested geoengineering concepts to artificially enhance the stratospheric aerosol loading. A special focus will also be put on the 2010/11 Arctic winter that saw the first Arctic Ozone hole, including an impact study on surface UV radiation in the densely populated northern mid-latitudes.

  11. Modeled impacts of stratospheric ozone and water vapor perturbations with implications for high-speed civil transport aircraft

    SciTech Connect

    Rind, D.; Lonergan, P.

    1995-04-20

    Ozone and water vapor perturbations are explored in a series of experiments with the Goddard Institute for Space Studies climate/middle atmosphere model. Large perturbations, and realistic perturbations, to stratospheric ozone and water vapor are investigated, with and without allowing sea surface temperatures to change, to illuminate the nature of the dynamic and climatic impact. Removing ozone in the lower stratosphere without allowing sea surface temperatures to change results in in situ cooling of up to 10{degrees}C in the tropical lower stratosphere, with radiative warming about half as large in the middle stratosphere. The temperature changes induce increases in tropospheric and lower stratospheric eddy energy and in the lower stratosphere residual circulation of the order of 10%. When sea surface temperatures are allowed to respond to this forcing, the global, annual-average surface air temperature cools by about 1{degrees}C as a result of the decreased ozone greenhouse capacity, reduced tropospheric water vapor, and increased cloud cover. For more realistic ozone changes, as defined in the High-Speed Research Program/Atmospheric Effects of Stratospheric Aircraft reports, the stratosphere generally cools by a few tenths degrees Celsius. In this case, the surface air temperature change is not significant, due to the conflicting influences of stratospheric ozone reduction and tropospheric ozone increase, although high-latitude cooling of close to 0.5{degrees}C does occur consistently. With a more realistic increase of stratospheric water vapor of 7%, the middle atmosphere cools by 0.5{degrees}C or less, and the surface temperature change is neither significant nor consistent. Overall, the experiments emphasize that stratospheric changes affect tropospheric dynamics, and that tropospheric feedback processes and natural variability are important when assessing the climatic response to aircraft emissions. 21 refs., 20 figs., 3 tabs.

  12. Ozone Hole Airborne Arctic Stratospheric Expedition (Pre-Flight)

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The first segment of this video gives an overview of the Ozone Hole Airborne Arctic Stratospheric Expedition, an international effort using balloon payloads, ground based instruments, and airborne instruments to study ozone depletion and the hole in the ozone over Antarctica which occurs every spring. False color imagery taken from NASA's Nimbus 7 satellite which documents daily changes in ozone is also shown. The second segment of this video shows actual take-off and flight footage of the two aircraft used in the experiment: the DC-8 Flying Laboratory and the high flying ER-2.

  13. Impact of Stratospheric Ozone Zonal Asymmetries on the Tropospheric Circulation

    NASA Technical Reports Server (NTRS)

    Tweedy, Olga; Waugh, Darryn; Li, Feng; Oman, Luke

    2015-01-01

    The depletion and recovery of Antarctic ozone plays a major role in changes of Southern Hemisphere (SH) tropospheric climate. Recent studies indicate that the lack of polar ozone asymmetries in chemistry climate models (CCM) leads to a weaker and warmer Antarctic vortex, and smaller trends in the tropospheric mid-latitude jet and the surface pressure. However, the tropospheric response to ozone asymmetries is not well understood. In this study we report on a series of integrations of the Goddard Earth Observing System Chemistry Climate Model (GEOS CCM) to further examine the effect of zonal asymmetries on the state of the stratosphere and troposphere. Integrations with the full, interactive stratospheric chemistry are compared against identical simulations using the same CCM except that (1) the monthly mean zonal mean stratospheric ozone from first simulation is prescribed and (2) ozone is relaxed to the monthly mean zonal mean ozone on a three day time scale. To analyze the tropospheric response to ozone asymmetries, we examine trends and quantify the differences in temperatures, zonal wind and surface pressure among the integrations.

  14. ENSO effects on stratospheric ozone: A nudged model perspective

    NASA Astrophysics Data System (ADS)

    Braesicke, Peter; Kirner, Oliver; Versick, Stefan; Joeckel, Patrick

    2015-04-01

    The El Niño/Southern Oscillation (ENSO) phenomenon is an important pacemaker for interannual variability in the Earth's atmosphere. ENSO impacts on ozone have been observed and modelled for the stratosphere and the troposphere. It is well recognized that attribution of ENSO variability is important for trend detection. ENSO impacts in low latitudes are easier to detect, because the response emerges close (temporally and spatially) to the forcing. Moving from low to high latitudes it becomes increasingly difficult to isolate ENSO driven variability, due to time-lags involved and many other modes of variability playing a role as well. Here, we use a nudged version of the EMAC chemistry-climate model to evaluate ENSO impacts on ozone over the last 35 years. In the nudged mode configuration EMAC is not entirely free running. The tropospheric meteorology is constrained using ERA-Interim data. Only the upper stratosphere and the composition (including ozone) are calculated without additional observational constraints. Using lagged correlations and supported by additional idealised modelling, we describe the ENSO impact on tropospheric and stratospheric ozone in the EMAC system. We trace the ENSO signal from the tropical lower troposphere to the polar lower and middle stratosphere. Instead of distinguishing tropospheric and stratospheric responses, we present a coherent approach detecting the ENSO signal as a function of altitude, latitude and time, and demonstrate how a concise characterisation of the ENSO impact aids improved trend detection.

  15. Reducing Uncertainty in Chemistry Climate Model Predictions 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 predict the future evolution of stratospheric ozone as ozone-depleting substances decrease and greenhouse gases increase, cooling the stratosphere. CCM predictions exhibit 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 chlorine change from that due to climate change. We show that the sensitivity of lower atmosphere ozone to chlorine change deltaO3/deltaCly is a near linear function of partitioning of total inorganic chlorine (Cly) into its reservoirs; both Cly and its partitioning are controlled by lower atmospheric transport. CCMs with realistic transport agree with observations for chlorine reservoirs and produce similar ozone responses to chlorine change. After 2035 differences in response to chlorine contribute little to the spread in CCM results as the anthropogenic contribution to Cly becomes unimportant. Differences among upper stratospheric ozone increases due to temperature decreases are explained by differences in ozone sensitivity to temperature change deltaO3/deltaT due to different contributions from various ozone loss processes, each with their own temperature dependence. In the lower atmosphere, tropical ozone decreases caused by a predicted speed-up in the Brewer-Dobson circulation may or may not be balanced by middle and high latitude increases, contributing most to the spread in late 21st century predictions.

  16. 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.

  17. Atmospheric bromine and ozone perturbations in the lower stratosphere

    NASA Technical Reports Server (NTRS)

    Yung, Y. L.; Pinto, J. P.; Watson, R. T.; Sander, S. P.

    1980-01-01

    The role of bromine compounds in the photochemistry of the natural and perturbed stratosphere has been reexamined using an expanded reaction scheme and the results of recent laboratory studies of several key reactions. The most important finding is that through the reaction BrO + ClO yielding Br + Cl + O2 there is a synergistic effect between bromine and chlorine which results in an efficient catalytic destruction of ozone in the lower stratosphere. One-dimensional photochemical model results indicate that BrO is the major bromine species throughout the stratosphere, followed by BrONO2, HBr, HOBr and Br. It is shown from the foregoing that bromine is more efficient than chlorine as a catalyst for destroying ozone, and the implications for stratospheric ozone of possible future growth in the industrial and agricultural use of bromine are discussed. Bromine concentrations of 20 pptv (2 x 10 to the -11th power), as suggested by recent observations, can decrease the present-day integrated ozone column density by 2.4%, and can enhance ozone depletion from steady-state chlorofluoromethane release at 1973 rates by a factor of 1.1-1.2.

  18. Lidar measurements of stratospheric ozone during the STOIC campaign

    NASA Astrophysics Data System (ADS)

    McGee, Thomas J.; Ferrare, Richard A.; Whiteman, David N.; Butler, James J.; Burris, John F.; Owens, Melody A.

    1995-05-01

    The NASA Goddard Space Flight Center's Stratospheric Ozone Lidar Trailer Experiment participated in the Stratospheric Ozone Intercomparison Campaign (STOIC) at Table Mountain, California, from July 20 to August 2, 1989. From 20 to 39 km the average Goddard Space Flight Center (GSFC) profile agreed with the STOIC reference profile to better than 5%. The STOIC reference profile was generated by averaging all profiles from the eight participating instruments. In this same altitude region the GSFC and the Jet Propulsion Laboratory lidar average profiles also agreed to better than 5%. Similar results were found for an intercomparison of the lidar data with ozone data from ECC sondes launched from Table Mountain and from San Nicholas Island. The results of the intercomparison have led to a number of modifications to the GSFC lidar which have greatly improved the reliability of the ozone data, particularly at altitudes below 20 km and above 40 km.

  19. Lidar measurements of stratospheric ozone during the STOIC campaign

    SciTech Connect

    McGee, T.J.; Burris, J.F.; Ferrare, R.A.

    1995-05-20

    The NASA Goddard Space Flight Center`s Stratospheric Ozone Lidar Trailer Experiment participated in the Stratospheric Ozone Intercomparison Campaign (STOIC) at Table Mountain, California, from July 20 to August 2, 1989. From 20 to 39 km the average Goddard Space Flight Center (GSFC) profile agreed with the STOIC reference profile to better than 5%. The STOIC reference profile was generated by averaging all profiles from the eight participating instruments. In this same altitude region the GSFC and the Jet Propulsion Laboratory lidar average profiles also agreed to better than 5%. Similar results were found for an intercomparison of the lidar data with ozone data from EC sondes launched from Table Mountain and from San Nicholas Island. The results of the intercomparison have led to a number of modifications to the GSFC lidar which have greatly improved the reliability of the ozone data, particularly at altitudes below 20 km and above 40 km. 10 refs., 9 figs.

  20. Ozone in the troposphere and stratosphere, part 2

    NASA Technical Reports Server (NTRS)

    Hudson, Robert D. (Editor)

    1994-01-01

    This is the second of a 2-part Conference Publication. This document contains papers presented at the 1992 Quadrennial Ozone Symposium held at Charlottesville, Virginia, from June 4-13, 1992. The papers cover topics in both Tropospheric and Stratospheric research. These topics include ozone trends and climatology, ground based, aircraft, balloon, rocket and satellite measurements, Arctic and Antarctic research, global and regional modeling, and volcanic effects.

  1. Ozone Production and Loss Rate Measurements in the Middle Stratosphere

    NASA Technical Reports Server (NTRS)

    Jucks, Kenneth W.; Johnson, David G.; Chance, K. V.; Traub, Wesley A.; Salawitch, R. J.; Stachnik, R. A.

    1996-01-01

    The first simultaneous measurements of HO(x), NO(x), and Cl(x) radicals in the middle stratosphere show that NO(x) catalytic cycles dominate loss of ozone (O3) for altitudes between 24 and 38 km; Cl(x) catalytic cycles are measured to be less effective than previously expected; and there is no 'ozone deficit' in the photochemically dominated altitude range from 31 and 38 km, contrary to some previous theoretical studies.

  2. Ozone in the Troposphere and Stratosphere, part 1

    NASA Technical Reports Server (NTRS)

    Hudson, Robert D.

    1994-01-01

    This is the first part of a 2-part Conference Publication. This document contains papers presented at the 1992 Quadrennial Ozone Symposium held at the Charlottesville, Virginia, from June 4-13, 1992. The papers cover topics in both Tropospheric and Stratospheric research. These topics include ozone trends and climatology, ground based, aircraft, balloon, rocket and satellite measurements, Arctic and Antarctic research, global and regional modeling, and volcanic effects.

  3. 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

  4. Balloon borne measurements of Stratospheric ozone over Hyderabad, India

    NASA Astrophysics Data System (ADS)

    Manchanda, R. K.; Sreenivasan, S.; Sinha, P. R.

    We conducted a one year campaign for the study of stratospheric ozone concentration and its variability along with other metrological parameters over Hyderabad. The flights were made every 15 days using 5000 cu m plastic balloons except during the rainy days when rubber balloon were employed. Ozone plays important role in the chemistry and dynamics of the atmosphere. In troposphere, ozone represents one of the most active gases involved in photochemical reactions as many factors influence tropospheric ozone concentration. Tropospheric ozone also plays a central role in the oxidative chemistry of the troposphere and has an important impact on the radiative balance of the atmosphere and therefore continuous observation program is necessary to assess the ozone budget. The measurement of other meteorological parameters is also essential since an atmospheric composition is intimately linked to the meteorological conditions, under which chemical and transport processes occur. The measurements were made using ozonesonde (Electro Chemical Cell) coupled with GPS RS80-15N radiosonde.

  5. Tunguska meteor fall of 1908: effects on stratospheric ozone

    SciTech Connect

    Turco, R.P.; Toon, O.B.; Park, C.; Whitten, R.C.; Pollack, J.B.; Noerdlinger, P.

    1981-10-02

    In 1908, when the giant Tunguska meteor disintegrated in the earth's atmosphere over Siberia, it may have generated as much as 30 million metric tons of nitric oxide (NO) in the stratosphere and mesosphere. The photochemical aftereffects of the event have been simulated using a comprehensive model of atmospheric trace composition. Calculations indicate that up to 45 percent of the ozone in the Northern Hemisphere may have been depleted by Tunguska's nitric oxide cloud early in 1909 and large ozone reductions may have persisted until 1912. Measurements of atmospheric transparency by the Smithsonian Astrophysical Observatory for the years 1909 to 1911 show evidence of a steady ozone recovery from unusually low levels in early 1909, implying a total ozone deficit of 30 +- 15 percent. The coincidence in time between the observed ozone recovery and the Tungska meteor fall indicates that the event may provide a test of current ozone depletion theories.

  6. 76 FR 47451 - Protection of Stratospheric Ozone: Adjustments to the Allowance System for Controlling HCFC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-05

    ... the Montreal Protocol) regarding harmful effects on the stratospheric ozone layer associated with a... information about EPA's Stratospheric Ozone Protection regulations, the science of ozone layer depletion, and... Conditioning; Montreal Protocol--Montreal Protocol on Substances that Deplete the Ozone Layer; MOP--Meeting...

  7. Distribution of total ozone and stratospheric ozone in the tropics - Implications for the distribution of tropospheric ozone

    NASA Technical Reports Server (NTRS)

    Fishman, Jack; Larsen, Jack C.

    1987-01-01

    Climatologies of total columnar ozone and integrated stratospheric ozone amounts at low latitudes (15 deg N to 15 deg S), derived from satellite observations, are presented. A significant longitudinal variability in total ozone is present, with highest values generally located between 60 deg W and 60 deg E. The integrated stratospheric component of total ozone, on the other hand, does not exhibit a longitudinal preference for high values. Therefore it is hypothesized that the climatological longitudinal distribution of total ozone reflects the variability of the abundance of tropospheric ozone at low latitudes. Furthermore, it is speculated that in situ photochemical production of ozone resulting from biomass burning may be responsible for the observed enhancement of total ozone at these longitudes.

  8. Effects on stratospheric ozone from high-speed civil transport: Sensitivity to stratospheric aerosol loading

    NASA Technical Reports Server (NTRS)

    Weisenstein, Debra K.; Ko, Malcolm K. W.; Rodriguez, Jose M.; Sze, Nien-Dak

    1993-01-01

    The potential impact of high-speed civil transport (HSCT) aircraft emissions on stratospheric ozone and the sensitivity of these results to changes in aerosol loading are examined with a two-dimensional model. With aerosols fixed at background levels, calculated ozone changes due to HSCT aircraft emissions range from negligible up to 4-6% depletions in column zone at northern high latitudes. The magnitude of the ozone change depends mainly on the NO(x) increase due to aircraft emissions, which depends on fleet size, cruise altitude, and engine design. The partitioning of the odd nitrogen species in the lower stratosphere among NO, NO2, N2O5, is strongly dependent on the concentration of sulfuric acid aerosol particles, and thus the sensitivity of O3 to NO(x) emissions changes when the stratospheric aerosol loading changes. Aerosol concentrations 4 times greater than background levels have not been unusual in the last 2 decades. Our model results show that a factor of 4 increase in aerosol loading would significantly reduce the calculated ozone depletion due to HSCT emissions. Because of the neutral variabiltiy of stratospheric aerosols, the possible impact of HSCT emissions on ozone must be viewed as a range of possible results.

  9. Effects of stratospheric ozone recovery on tropospheric chemistry and air quality

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Wu, S.; Wang, Y.

    2013-08-01

    The stratospheric ozone has decreased greatly since 1980 due to ozone depleting substances (ODSs). As a result of the implementation of the Montreal Protocol and its amendments and adjustments, stratospheric ozone is expected to recover towards its pre-1980 level in the coming decades. We examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). Significant decreases in surface ozone photolysis rates due to stratospheric ozone recovery are simulated. Increases in ozone lifetime by up to 7% are calculated in the troposphere. The global average OH decreases by 1.74% and the global burden of tropospheric ozone increases by 0.78%. The perturbations to tropospheirc ozone and surface ozone show large seasonal and spatial variations. General increases in surface ozone are calculated for each season, with increases by up to 5% for some regions.

  10. Impacts of Stratospheric Ozone Change on Tropospheric Chemistry and Air Quality

    NASA Astrophysics Data System (ADS)

    Wu, S.; Zhang, H.

    2013-05-01

    The stratospheric ozone has decreased greatly since 1980 due to ozone depleting substances (ODSs). As a result of the implementation of the Montreal Protocol and its Amendments and Adjustments, stratospheric ozone is expected to recover towards its pre-1980 level in the coming decades. We examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). Significant decreases in surface ozone photolysis rates due to stratospheric ozone recovery are simulated. Increases in ozone lifetime by up to 7% are calculated in the troposphere. The global average OH decreases by 1.74% and the global burden of tropospheric ozone increased by 0.78%. The perturbations to tropospheirc ozone and surface ozone show large seasonal and spatial variations. General increases in surface ozone are calculated for each season, with increases by up to 5% for some regions.

  11. Vapor Measurements from the GSFC Stratospheric Ozone Lidar

    NASA Technical Reports Server (NTRS)

    McGee, T.

    2003-01-01

    Water vapor measurements from the GSFC Stratospheric Ozone Lidar were made for the first time during a campaign at NOAA's Mauna Loa Observatory. Comparisons were made among the GSFC lidar, the NOAA Lidar and water vapor sondes which were flown from the observatory at times coincident with the lidar measurements.

  12. Relative effects on stratospheric ozone of halogenated methanes and ethanes of social and industrial interest

    NASA Technical Reports Server (NTRS)

    Fisher, Donald A.; Hales, Charles H.; Filkin, David L.; Ko, Malcolm K. W.; Sze, N. Dak; Connell, Peter S.; Wuebbles, Donald J.; Isaksen, Ivar S. A.; Stordal, Frode

    1990-01-01

    Four atmospheric modeling groups have calculated relative effects of several halocarbons (chlorofluorocarbons (CFC's)-11, 12, 113, 114, and 115; hydrochlorofluorocarbons (HCFC's) 22, 123, 124, 141b, and 142b; hydrofluorocarbons (HFC's) 125, 134a, 143a, and 152a, carbon tetrachloride; and methyl chloroform) on stratospheric ozone. Effects on stratospheric ozone were calculated for each compound and normalized relative to the effect of CFC-11. These models include the representations for homogeneous physical and chemical processes in the middle atmosphere but do no account for either heterogeneous chemistry or polar dynamics which are important in the spring time loss of ozone over Antarctica. Relative calculated effects using a range of models compare reasonably well. Within the limits of the uncertainties of these model results, compounds now under consideration as functional replacements for fully halogenated compounds have modeled stratospheric ozone reductions of 10 percent or less of that of CFC-11. Sensitivity analyses examined the sensitivity of relative calculated effects to levels of other trace gases, assumed transport in the models, and latitudinal and seasonal local dependencies. Relative effects on polar ozone are discussed in the context of evolving information on the special processes affecting ozone, especially during polar winter-springtime. Lastly, the time dependency of relative effects were calculated.

  13. Impact of future nitrous oxide and carbon dioxide emissions on the stratospheric ozone layer

    NASA Astrophysics Data System (ADS)

    Stolarski, Richard S.; Douglass, Anne R.; Oman, Luke D.; Waugh, Darryn W.

    2015-03-01

    The atmospheric levels of human-produced chlorocarbons and bromocarbons are projected to make only small contributions to ozone depletion by 2100. Increases in carbon dioxide (CO2) and nitrous oxide (N2O) will become increasingly important in determining the future of the ozone layer. N2O increases lead to increased production of nitrogen oxides (NOx), contributing to ozone depletion. CO2 increases cool the stratosphere and affect ozone levels in several ways. Cooling decreases the rate of many photochemical reactions, thus slowing ozone loss rates. Cooling also increases the chemical destruction of nitrogen oxides, thereby moderating the effect of increased N2O on ozone depletion. The stratospheric ozone level projected for the end of this century therefore depends on future emissions of both CO2 and N2O. We use a two-dimensional chemical transport model to explore a wide range of values for the boundary conditions for CO2 and N2O, and find that all of the current scenarios for growth of greenhouse gases project the global average ozone to be larger in 2100 than in 1960.

  14. Measurements of stratospheric ozone by rocket ozonesondes in Japan

    NASA Technical Reports Server (NTRS)

    Watanabe, Takashi; Ogawa, Toshihiro

    1994-01-01

    A small optical ozone instrument has been developed for a rocket-borne dropsonde to measure the altitude profile of stratospheric ozone. It consists of a four-color filter photometer that measures the attenuation of sunlight as a function of altitude at four wavelengths in the middle ultraviolet. The ozone dropsonde is launched aboard a meteorological rocket MT-135, providing the altitude profiles of ozone as well as atmospheric temperature and wind. The rocket launchings have been carried out five times since August 1990 at Uchinoura (31 deg N, 131 deg E), Japan to measure ozone concentration from 52 to 20 km altitudes during the slow fall of the dropsonde. The ozone profiles measured in summer (August 27, 1990; Sep. 11 and 12, 1991) were very stable above an altitude of 28km. where as those measured in winter (Feb. 9, and 11, 1991) showed considerable day-to-day variations at the stratospheric altitudes. Ozone, temperature and wind profiles measured simultaneously by both rocket and balloon ozonsondes are compared with CIRA 1986 model atmosphere.

  15. Stratospheric ozone in the 21st Century: The chlorofluorocarbon problem

    SciTech Connect

    Rowland, F.S. )

    1991-04-01

    Ozone (O{sub 3}) exists in a dynamic equilibrium in the stratosphere, balanced between formation by solar ultraviolet photolysis ({lambda} < 242 nm) of molecular O{sub 2} (O + O{sub 2} {yields} O{sub 3}) and destruction by various chemical processes including several chain reaction sequences triggered by HO{sub x}, NO{sub x}, and ClO{sub x} radicals. The ozone dissipates over Antarctica by November through northward mixing, only to begin reappearing in late August of the following year. Substantial ozone losses have also appeared, although not as spectacularly as over Antarctica, in the Northern Hemisphere's temperate and polar regions. The primary cause for the Antarctic ozone loss, and the probable cause for the northern losses, is the increasing concentration in the stratosphere of anthropogenic chlorine, especially chlorine released by solar UV photolysis from chlorofluorocarbon (CFC) compounds such as CCl{sub 2}F{sub 2} (CFC-12), CCl{sub 3}F (CFC-11) and CCl{sub 2}FCClF{sub 2} (CFC-113). Because these molecules have average atmospheric lifetimes of many decades, excess anthropogenic chlorine will persist in the stratosphere for comparable time periods, and the Antarctic ozone hole will be an important atmospheric phenomenon throughout the 21st century.

  16. Tropospheric response to an 'ozone depletion'-like polar stratospheric cooling

    NASA Astrophysics Data System (ADS)

    Sun, L.; Chen, G.; Robinson, W. A.

    2013-12-01

    By following the setup of Kushner and Polvani (2006) in a simplified dynamical model, we add a polar stratospheric cooling in the springtime to mimic the ozone depletion, and try to investigate the role of polar vortex breakdown, also known as stratospheric final warming (SFW), in the tropospheric response to stratospheric changes. Overall, the circulation anomaly associated with such cooling bears a remarkable resemblance to the Southern Hemisphere climate trends due to ozone depletion, including poleward shift of the tropospheric jet and poleward expansion of the Hadley cell. We then categorize the 80 members into those SFWs are delayed, and those SFWs are not, and calculate the response separately. The response for the years in which SFWs are delayed are very similar to the total one, while the stratosphere is only characterized by the localized cooling for those years in which SFWs are not delayed, without any clear downward influence. This suggests that ozone depletion affects the Southern Hemisphere climate through delaying the SFWs. We also find that interannual variability in the stratospheric and tropospheric circulation can be organized by the timing of SFWs, similar to the observed climate trends.

  17. Upper-Stratospheric Ozone Trends 1979-1998

    NASA Technical Reports Server (NTRS)

    Newchurch, M. J.; Cunnold, Derek; Bishop, Lane; Flynn, Lawrence E.; Godin, Sophie; Frith, Stacey Hollandsworth; Hood, Lon; Miller, Alvin J.; Oltmans, Sam; Randel, William

    2002-01-01

    Extensive analyses of ozone observations between 1978 and 1998 measured by Dobson Umkehr, Stratospheric Aerosol and Gas Experiment (SAGE) I and II, and Solar Backscattered Ultraviolet (SBUV) and (SBUV)/2 indicate continued significant ozone decline throughout the extratropical upper stratosphere from 30-45 km altitude. The maximum annual linear decline of -0.8 +/- 0.2 %/yr(2sigma) occurs at 40 km and is well described in terms of a linear decline modulated by the 11-year solar variation. The minimum decline of -0.110.1% yr-1(2o) occurs at 25 km in midlatitudes, with remarkable symmetry between the Northern and Southern Hemispheres at 40 km altitude. Midlatitude upper-stratospheric zonal trends exhibit significant seasonal variation (+/- 30% in the Northern Hemisphere, +/- 40% in the Southern Hemisphere) with the most negative trends of -1.2%/yr occurring in the winter. Significant seasonal trends of -0.7 to -0.9%/yr occur at 40 km in the tropics between April and September. Subjecting the statistical models used to calculate the ozone trends to intercomparison tests on a variety of common data sets yields results that indicate the standard deviation between trends estimated by 10 different statistical models is less than 0.1%/yr in the annual-mean trend for SAGE data and less than 0.2%/yr in the most demanding conditions (seasons with irregular, sparse data) [World Meteorological Organization (WMO), 1998]. These consistent trend results between statistical models together with extensive consistency between the independent measurement-system trend observations by Dobson Umkehr, SAGE I and II, and SBUV and SBUV/2 provide a high degree of confidence in the accuracy of the declining ozone amounts reported here. Additional details of ozone trend results from 1978 to 1996 (2 years shorter than reported here) along with lower-stratospheric and tropospheric ozone trends, extensive intercomparisons to assess relative instrument drifts, and retrieval algorithm details are

  18. Prediction of Dynamical Impact of Changes in Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Cunnold, Derek M.

    1998-01-01

    Under this grant one paper by Lou et al and a second paper by Kindler et al is in journal. These papers both describe N2O simulations using UKMO and Goddard assimilated wind fields and comparisons of the results against CLAES N2O observations. The results of these studies indicate some of the difficulties of using the assimilated wind fields, and the vertical motions in particular, in simulating long term variations in trace gases in the stratosphere. On the other hand, qualitatively the results possess a number of features of the observations even on time scales longer than a month or two. More recently we have started to examine results obtained using NCAR models a 3D version of which also uses the UKMO assimilated wind fields. Calculations have already been made with their 2D model with emphasis on the seasonal cycle in ozone at high latitudes in the upper stratosphere. Simultaneously trends in stratospheric ozone have been studied in detail from SAGE and UARS observations. Moreover, observations of the trends since 1984 do not show a significant interhemispheric asymmetry in upper stratospheric ozone. Therefore any asymmetry in the trends must have occurred prior to the mid-eighties and would most likely have been related to interhemispheric differences in upper stratospheric temperature trends. Another activity has been to compile an ozone climatology from UARS and SAGE observations. This effort has been performed as part of a UARS team activity to assemble a climatology of all the UARS long-lived trace gases for 1992-1993.

  19. Validation of GOMOS ozone precision estimates in the stratosphere

    NASA Astrophysics Data System (ADS)

    Sofieva, V. F.; Tamminen, J.; Kyrölä, E.; Laeng, A.; von Clarmann, T.; Dalaudier, F.; Hauchecorne, A.; Bertaux, J.-L.; Barrot, G.; Blanot, L.; Fussen, D.; Vanhellemont, F.

    2014-07-01

    Accurate information about uncertainties is required in nearly all data analyses, e.g., inter-comparisons, data assimilation, combined use. Validation of precision estimates (viz., the random component of estimated uncertainty) is important for remote sensing measurements, which provide the information about atmospheric parameters by solving an inverse problem. For the Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument, this is a real challenge, due to the dependence of the signal-to-noise ratio (and thus precision estimates) on stellar properties, small number of self-collocated measurements, and growing noise as a function of time due to instrument aging. The estimated ozone uncertainties are small in the stratosphere for bright star occultations, which complicates validation of precision values, given the natural ozone variability. In this paper, we discuss different methods for geophysical validation of precision estimates and their applicability to GOMOS data. We propose a simple method for validation of GOMOS precision estimates for ozone in the stratosphere. This method is based on comparisons of differences in sample variance with differences in uncertainty estimates for measurements from different stars selected in a region of small natural variability. For GOMOS, the difference in sample variances for different stars at tangent altitudes 25-45 km is well explained by the difference in squared precisions, if the stars are not dim. Since this is observed for several stars, and since normalized χ2 is close to 1 for these occultations in the stratosphere, we conclude that the GOMOS precision estimates are realistic in occultations of sufficiently bright stars. For dim stars, errors are overestimated due to improper accounting of the dark charge correction uncertainty in the error budget. The proposed method can also be applied to stratospheric ozone data from other instruments, including multi-instrument analyses.

  20. A New Raman DIAL Technique for Measuring Stratospheric Ozone in the Presence of Volcanic Aerosols

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Mcgee, Thomas J.; Gross, Michael; Heaps, William S.; Ferrare, Richard

    1992-01-01

    This paper describes a new lidar scheme to measure stratospheric ozone in the presence of heavy volcanic aerosol loading. The eruptions of the Philippine volcano Pinatubo during June 1991 ejected large amounts of sulfur dioxide into the atmosphere to altitudes of at least 30 km. The resulting aerosols have severely affected the measurements of stratospheric ozone when using traditional Rayleigh differential absorption lidar (DIAL) technique, in which the scattering mechanism is almost entirely Rayleigh and which assumes a small amount or no aerosols. In order to extract an ozone profile in the regions below about 30 km where the Rayleigh lidar returns are contaminated by aerosol scattering from Mt. Pinatubo cloud, we have used a Raman lidar technique, where the scattering mechanism depends solely on molecular nitrogen. In this scheme there is no aerosol scattering component to the backscattered lidar return. Using this technique in conjunction with the Rayleigh DIAL measurement, the GSFC stratospheric ozone lidar has measured ozone profiles between 15 and 50 km during the recently held UARS correlative measurement campaign (February-March 1992) at JPL's Table Mountain Facility in California.

  1. Effect of zonal asymmetries in stratospheric ozone on simulated Southern Hemisphere climate trends

    NASA Astrophysics Data System (ADS)

    Waugh, D. W.; Oman, L.; Newman, P. A.; Stolarski, R. S.; Pawson, S.; Nielsen, J. E.; Perlwitz, J.

    2009-09-01

    Stratospheric ozone is represented in most climate models by prescribing zonal-mean fields. We examine the impact of this on Southern Hemisphere (SH) trends using a chemistry climate model (CCM): multi-decadal simulations with interactive stratospheric chemistry are compared with parallel simulations using the same model in which the zonal-mean ozone is prescribed. Prescribing zonal-mean ozone results in a warmer Antarctic stratosphere when there is a large ozone hole, with much smaller differences at other times. As a consequence, Antarctic temperature trends for 1960 to 2000 and 2000 to 2050 in the CCM are underestimated when zonal-mean ozone is prescribed. The impacts of stratospheric changes on the tropospheric circulation (i.e., summertime trends in the SH annular mode) are also underestimated. This shows that SH trends related to ozone depletion and recovery are underestimated when interactions between stratospheric ozone and climate are approximated by an imposed zonal-mean ozone field.

  2. 77 FR 29341 - Protection of Stratospheric Ozone: Request for Methyl Bromide Critical Use Exemption Applications...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-17

    ... to the provisions of the Montreal Protocol on Substances that Deplete the Ozone Layer for... AGENCY Protection of Stratospheric Ozone: Request for Methyl Bromide Critical Use Exemption Applications... FURTHER INFORMATION CONTACT: General Information: U.S. EPA Stratospheric Ozone Information Hotline,...

  3. Reductions in ozone at high concentrations of stratospheric halogens

    NASA Technical Reports Server (NTRS)

    Prather, M. J.; Mcelroy, M. B.; Wofsy, S. C.

    1984-01-01

    An increase in the concentration of inorganic chlorine to levels comparable to that of oxidized reactive nitrogen could cause a significant change in the chemistry of the lower stratosphere leading to a reduction potentially larger than 15 percent in the column density of ozone. This could occur, for example by the middle of the next century, if emissions of man-made chlorocarbons were to grow at a rate of 3 percent per year. Ozone could be further depressed by release of industrial bromocarbon.

  4. Stratospheric ozone measurement with an infrared heterodyne spectrometer

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Kostiuk, T.; Mumma, M. J.; Buhl, D.; Kunde, V. G.; Brown, L. W.

    1978-01-01

    A stratospheric ozone absorption line in the 10 microns band was measured and resolved completely, using an infrared heterodyne spectrometer with spectral resolution of 5 MHz (0.000167 cm to -1 power). The vertical concentration profile of stratospheric ozone was obtained through an analytical inversion of the measured spectral line profile. The absolute total column density was 0.34 cm atm with a peak mixing ratio occurring at approximately 24 km. The (7,1,6) to (7,1,7) O3 line center frequency was found to be 1043.1775 + or - 0.00033 cm to toe -1 power, or 430 + or - 10 MHz higher than the P(24) CO2 laser line frequency.

  5. Stratospheric ozone measurement with an infrared heterodyne spectrometer

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Kostiuk, T.; Mumma, M. J.; Buhl, D.; Kunde, V. G.; Brown, L. W.; Spears, D.

    1978-01-01

    A stratospheric ozone absorption line in the 10 micron band was measured and resolved completely, using an infrared heterodyne spectrometer with a spectral resolution of 5 MHz. The vertical concentration profile of stratospheric ozone was obtained through an analytical inversion of the measured spectra line profile. The absolute total column density was 0.32 plus or minus 0.02 cm-atm with a peak mixing ratio occurring at approximately 24 km. The (7,1,6) - (7,1,7) O3 line center frequency was found to be 1043.1772 plus or minus 0.00033 cm/1 or 420 plus or minus 10 MHz higher than the P(24) CO2 laser line frequency.

  6. Early work on the stratospheric ozone depletion-CFC issue

    NASA Astrophysics Data System (ADS)

    Molina, M.

    2012-12-01

    I became involved with the atmospheric chemistry of chlorofluorocarbons (CFCs) shortly after joining Sherry Rowland's research group at the University of California, Irvine, in 1973. CFCs had been detected in the troposphere by James Lovelock in 1971, and the question we set out to answer was the fate of these compounds of industrial origin in the environment, as well as possibly identifying any consequences of their accumulation in the atmosphere. After examining many potential sinks for these compounds we realized that because of their unusual stability the most likely destruction process was photolysis in the stratosphere. I carried out measurements of the absorption spectra of these compounds in the near ultraviolet; previous work involved only spectra in the far ultraviolet, not relevant for atmospheric chemistry. The results indicated that photolysis would take place in the upper stratosphere. I subsequently carried out calculations using one-dimensional atmospheric models to estimate their atmospheric residence times, which turned out to be many decades. We realized that the chlorine atoms generated by photolysis of the CFCs would participate in a catalytic chain reaction that would efficiently destroy ozone. Furthermore, we estimated that the amount of CFCs produced industrially was comparable to the amount of nitric oxide produced naturally in the stratosphere by the decomposition of nitrous oxide; work by Paul Crutzen and Harold Johnston had indicated that the abundance of ozone in the stratosphere was controlled by nitric oxide. We then formulated the hypothesis that the continued release of CFCs to the environment posed a threat to the stability of the ozone layer, and published our results in the journal Nature in 1974. The publication was noticed almost exclusively by the community of experts in stratospheric chemistry, and hence Sherry Rowland and I decided at that time that it was our responsibility to communicate this finding to society at large

  7. The effect of ozone depletion on the Southern Annular Mode and stratosphere-troposphere coupling

    NASA Astrophysics Data System (ADS)

    Dennison, Fraser; McDonald, Adrian; Morgenstern, Olaf

    2015-04-01

    The aim of this study is to investigate the influence of ozone depletion and recovery on the Southern Annular Mode (SAM) and stratosphere-troposphere coupling. Using the NIWA-UKCA chemistry-climate model, we compare reference runs with forcing due to greenhouse gases and ozone depleting substances to sensitivity simulations in which ozone depleting substances are fixed at their 1960 levels. We find that ozone depletion leads to an increased frequency of extreme anomalies and increased persistence of the SAM in the stratosphere as well as stronger, more persistent stratosphere-troposphere coupling. This change in the strength of the stratosphere-troposphere coupling has implications for extended range weather forecasting. Currently the stratosphere provides an appreciable amount of predictability to the troposphere on time scales of one or two months, however we find that this effect reduces over time as stratospheric ozone recovers to pre-ozone hole levels towards the latter part of this century.

  8. Decadal-Scale Responses in Middle and Upper Stratospheric Ozone From SAGE II Version 7 Data

    NASA Technical Reports Server (NTRS)

    Remsberg, E. E.

    2014-01-01

    Stratospheric Aerosol and Gas Experiment (SAGE II) version 7 (v7) ozone profiles are analyzed for their decadal-scale responses in the middle and upper stratosphere for 1991 and 1992-2005 and compared with those from its previous version 6.2 (v6.2). Multiple linear regression (MLR) analysis is applied to time series of its ozone number density vs. altitude data for a range of latitudes and altitudes. The MLR models that are fit to the time series data include a periodic 11 yr term, and it is in-phase with that of the 11 yr, solar UV (Ultraviolet)-flux throughout most of the latitude/ altitude domain of the middle and upper stratosphere. Several regions that have a response that is not quite in-phase are interpreted as being affected by decadal-scale, dynamical forcings. The maximum minus minimum, solar cycle (SClike) responses for the ozone at the low latitudes are similar from the two SAGE II data versions and vary from about 5 to 2.5% from 35 to 50 km, although they are resolved better with v7. SAGE II v7 ozone is also analyzed for 1984-1998, in order to mitigate effects of end-point anomalies that bias its ozone in 1991 and the analyzed results for 1991-2005 or following the Pinatubo eruption. Its SC-like ozone response in the upper stratosphere is of the order of 4%for 1984-1998 vs. 2.5 to 3%for 1991-2005. The SAGE II v7 results are also recompared with the responses in ozone from the Halogen Occultation Experiment (HALOE) that are in terms of mixing ratio vs. pressure for 1991-2005 and then for late 1992- 2005 to avoid any effects following Pinatubo. Shapes of their respective response profiles agree very well for 1992-2005. The associated linear trends of the ozone are not as negative in 1992-2005 as in 1984-1998, in accord with a leveling off of the effects of reactive chlorine on ozone. It is concluded that the SAGE II v7 ozone yields SC-like ozone responses and trends that are of better quality than those from v6.2.

  9. ROCOZ-A ozone measurements during the Stratospheric Ozone Intercomparison Campaign (STOIC)

    NASA Astrophysics Data System (ADS)

    Barnes, Robert A.; Parsons, Chester L.; Grothouse, Arthur P.

    1995-05-01

    We present a set of ROCOZ-A (rocket ozonesonde) ozone measurements during the October/November 1988 (pre-STOIC) and the July/August 1989 Stratospheric Ozone Intercomparison Campaign (STOIC) in southern California. ROCOZ-A and its associated electrochemical concentration cell (ECC) ozonesondes participated in the comparisons as established techniques for the validation of lidar and microwave instruments that have been proposed for the Network for the Detection of Stratospheric Change (NDSC). For the proposed network instruments, STOIC has provided a picture of their performance characteristics in 1989 and has given an estimate of their future performance in the NDSC. For ROCOZ-A, STOIC has added new information on its accuracy and precision. It is this continuing characterization that gives ROCOZ-A its value in comparisons. The STOIC comparisons show a shift of 5-6% in ROCOZ-A ozone densities (ROCOZ-A higher) from October/November 1988 to July/August 1989. This shift has been seen in comparisons with the Stratospheric Aerosol and Gas Experiment II (SAGE II), ECC ozonesondes, and the Jet Propulsion Laboratory (JPL) lidar. The source of this shift has not been determined. Until this new error source is resolved, we recommend that the previously quoted accuracy estimate for ROCOZ-A ozone measurements be increased from 5-7% to 8-10%. About 2% of the difference between ROCOZ-A ozone measurements and those from the proposed network instruments in 1989 appears to be due to differences in atmospheric ozone between the two STOIC sites. A correction for these site-to-site differences brings the ROCOZ-A ozone measurements within 10% of all of the other STOIC instruments, and the average agreement (ROCOZ-A 6% higher) becomes consistent with the historical set of ROCOZ-A comparisons. The STOIC comparisons have shown structures in stratospheric ozone that cannot be resolved by ROCOZ-A with its 4-km vertical resolution. In addition, comparisons with nighttime measurements from the

  10. The Impact of Geoengineering Aerosols on Stratospheric Temperature and Ozone

    NASA Technical Reports Server (NTRS)

    Heckendorn, P.; Weisenstein, D.; Fueglistaler, S.; Luo, B. P.; Rozanov, E.; Schraner, M.; Peter, T.; Thomason, L. W.

    2009-01-01

    Anthropogenic greenhouse gas emissions are warming the global climate at an unprecedented rate. Significant emission reductions will be required soon to avoid a rapid temperature rise. As a potential interim measure to avoid extreme temperature increase, it has been suggested that Earth's albedo be increased by artificially enhancing stratospheric sulfate aerosols. We use a 3D chemistry climate model, fed by aerosol size distributions from a zonal mean aerosol model, to simulate continuous injection of 1-10 Mt/a into the lower tropical stratosphere. In contrast to the case for all previous work, the particles are predicted to grow to larger sizes than are observed after volcanic eruptions. The reason is the continuous supply of sulfuric acid and hence freshly formed small aerosol particles, which enhance the formation of large aerosol particles by coagulation and, to a lesser extent, by condensation. Owing to their large size, these particles have a reduced albedo. Furthermore, their sedimentation results in a non-linear relationship between stratospheric aerosol burden and annual injection, leading to a reduction of the targeted cooling. More importantly, the sedimenting particles heat the tropical cold point tropopause and, hence, the stratospheric entry mixing ratio of H2O increases. Therefore, geoengineering by means of sulfate aerosols is predicted to accelerate the hydroxyl catalyzed ozone destruction cycles and cause a significant depletion of the ozone layer even though future halogen concentrations will be significantly reduced.

  11. The Impact of Geoengineering Aerosols on Stratospheric Temperature and Ozone

    NASA Technical Reports Server (NTRS)

    Heckendorn, P.; Weisenstein, D.; Fueglistaler, S.; Luo, B. P.; Rozanov, E.; Schraner, M.; Thomason, L. W.; Peter, T.

    2011-01-01

    Anthropogenic greenhouse gas emissions are warming the global climate at an unprecedented rate. Significant emission reductions will be required soon to avoid a rapid temperature rise. As a potential interim measure to avoid extreme temperature increase, it has been suggested that Earth's albedo be increased by artificially enhancing stratospheric sulfate aerosols. We use a 3D chemistry climate model, fed by aerosol size distributions from a zonal mean aerosol model. to simulate continuous injection of 1-10 Mt/a into the lower tropical stratosphere. In contrast to the case for all previous work, the particles are predicted to grow to larger sizes than are observed after volcanic eruptions. The reason is the continuous supply of sulfuric acid and hence freshly formed small aerosol particles, which enhance the formation of large aerosol particles by coagulation and, to a lesser extent, by condensation. Owing to their large size, these particles have a reduced albedo. Furthermore, their sedimentation results in a non-linear relationship between stratospheric aerosol burden and annual injection, leading to a reduction of the targeted cooling. More importantly, the sedimenting particles heat the tropical cold point tropopause and, hence, the stratospheric entry mixing ratio of H2O increases. Therefore, geoengineering by means of sulfate aerosols is predicted to accelerate the hydroxyl catalyzed ozone destruction cycles and cause a significant depletion of the ozone layer even though future halogen concentrations will he significantly reduced.

  12. Reactive nitrogen and its correlation with ozone in the lower Stratosphere and upper Troposhere

    SciTech Connect

    Murphy, D.M.; Fahey, D.W.; Liu, S.C.; Kelly, K.K. ); Proffitt, M.H.; Eubank, C.S.; Kawa, S.R. Univ. of Colorado, Boulder ); Chan, K.R. )

    1993-05-20

    The authors report on measurements of reactive nitrogen NO[sub y] and ozone O[sub 3] densities, and their correlations, in the lower stratosphere and upper troposphere as part of the Stratosphere-Troposphere Exchange Project (STEP), Airborne Antarctic Ozone Experiment (AAOE), and Airborne Arctic Stratospheric Expedition (AASE). Measurements were made from ER-2 aircraft in all these experiments. Reactive nitrogen measurements allow one to look at the total nitrogen load as it relates to atmospheric chemistry, and not have to follow each species and the complicated relationships they have in the atmosphere. A strong correlation is found between NO[sub y] and O[sub 3] in the lower stratosphere, but it is much weaker in the upper troposphere. Data is presented as the ratio of the two, and compared with model calculations, where an observed gradient from the tropics toward mid latitudes is not seen in the models. Lightning production of NO[sub y] may account for the lack of correlation in the upper troposphere. NO[sub y] condensation onto aerosols can also affect observed concentrations. In the tropical regions there are significant enough NO[sub y] densities in the upper troposphere to allow convective transport into the stratosphere.

  13. A Global Ozone Climatology from Ozone Soundings via Trajectory Mapping: A Stratospheric Perspective

    NASA Technical Reports Server (NTRS)

    Liu, J. J.; Tarasick, D. W.; Fioletov, V. E.; McLinden, C.; Zhao, T.; Gong, S.; Sioris, G.; Jin, J. J.; Liu, G.; Moeini, O.

    2013-01-01

    This study explores a domain-filling trajectory approach to generate a global ozone climatology from sparse ozonesonde data. Global ozone soundings of 51,898 profiles at 116 stations over 44 years (1965-2008) are used, from which forward and backward trajectories are performed for 4 days, driven by a set of meteorological reanalysis data. Ozone mixing ratios of each sounding from the surface to 26 km altitude are assigned to the entire path along the trajectory. The resulting global ozone climatology is archived monthly for five decades from the 1960s to the 2000s with grids of 5 degree 5 degree 1 km (latitude, longitude, and altitude). It is also archived yearly from 1965 to 2008. This climatology is validated at 20 ozonesonde stations by comparing the actual ozone sounding profile with that found through the trajectories, using the ozone soundings at all the stations except one being tested. The two sets of profiles are in good agreement, both individually with correlation coefficients between 0.975 and 0.998 and root mean square (RMS) differences of 87 to 482 ppbv, and overall with a correlation coefficient of 0.991 and an RMS of 224 ppbv. The ozone climatology is also compared with two sets of satellite data, from the Satellite Aerosol and Gas Experiment (SAGE) and the Optical Spectrography and InfraRed Imager System (OSIRIS). Overall, the ozone climatology compares well with SAGE and OSIRIS data by both seasonal and zonal means. The mean difference is generally under 20 above 15 km. The comparison is better in the northern hemisphere, where there are more ozonesonde stations, than in the southern hemisphere; it is also better in the middle and high latitudes than in the tropics, where assimilated winds are imperfect in some regions. This ozone climatology can capture known features in the stratosphere, as well as seasonal and decadal variations of these features. Furthermore, it provides a wealth of detail about longitudinal variations in the stratosphere such

  14. The impact of tropospheric planetary wave variability on stratospheric ozone

    SciTech Connect

    McElroy, Michael B.; Schneider, Hans R.

    2002-06-25

    The goal of this project was to improve understanding of the role of the stratosphere in inducing long-term variations of the chemical composition of the troposphere. Changes in stratospheric transport occur on decadel timescales in response to changes in the structure of planetary wave patterns, forced in the troposphere. For many important tracers, such as column amounts of ozone, this variability of the transport leads to changes with signatures very similar to those induced by anthropogenic releases of chemicals into the atmosphere. During this project, a new interactive two-dimensional model of the dynamics, chemistry and radiation of the stratosphere was developed. The model was used to interpret available data of tracers. It was found that a fairly coherent picture of tracer distributions is obtained when a layer of reduced gravity wave drag is assumed for the lower stratosphere. The results suggest that the power of models to predict variability in tracer transport in the upper troposphere and lower stratosphere is limited until current theories of gravity wave breaking have been refined.

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

    PubMed

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

    2012-05-01

    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. Sensitivity of Ozone to Bromine in the Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Salawitch, R. J.; Weisenstein, D. K.; Kovalenko, L. J.; Sioris, C. E.; Wennberg, P. O.; Chance, K.; Ko, M. K. W.; McLinden, C. A.

    2005-01-01

    Measurements of BrO suggest that inorganic bromine (Br(sub y)) at and above the tropopause is 4 to 8 ppt greater than assumed in models used in past ozone trend assessment studies. This additional bromine is likely carried to the stratosphere by short-lived biogenic compounds and their decomposition products, including tropospheric BrO. Including this additional bromine in an ozone trend simulation increases the computed ozone depletion over the past approx.25 years, leading to better agreement between measured and modeled ozone trends. This additional Br(sub y) (assumed constant over time) causes more ozone depletion because associated BrO provides a reaction partner for ClO, which increases due to anthropogenic sources. Enhanced Br(sub y) causes photochemical loss of ozone below approx.14 km to change from being controlled by HO(sub x) catalytic cycles (primarily HO2+O3) to a situation where loss by the BrO+HO2 cycle is also important.

  18. Stratospheric Ozone Trends Inferred from the OSIRIS Data Record

    NASA Astrophysics Data System (ADS)

    Degenstein, Doug; Bourassa, Adam; Roth, Chris

    2016-04-01

    The OSIRIS instrument onboard the Odin platform has been making high quality, vertically resolved ozone measurements since the autumn of 2001. These measurements, that span an altitude range that covers the cloud tops to 60 km, have been used within multiple studies to determine stratospheric ozone trends. In particular the OSIRIS measurements are an important component of the HARMOZ data set produced within the ESA ozone_cci program and the OSIRIS measurements have been merged with similar SAGE II measurements to produce ozone trend results that cover the period from the launch of SAGE II up to the present. As OSIRIS is the longest lived instrument that currently measures vertical ozone profiles, as long as the results remain of sufficiently high quality, its data products become exponentially more important every year. This paper will detail recent advancements in the OSIRIS ozone retrieval algorithm that have made the results more robust. A recent pointing correction will also be discussed. This correction has resulted in a reduction in magnitude of the positive trends reported recently by groups using the OSIRIS data record. These new results will be verified through comparison with trends derived using MLS measurements merged with SAGE II data where the merging process for the SAGE II - OSIRIS and SAGE II - MLS data sets was done in an identical fashion.

  19. Climate-chemistry interaction affecting tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Mao, Huiting

    1999-09-01

    Tropospheric ozone, an important radiative-chemical species, has been observed increasing especially at northern midlatitudes during the past few decades. This dissertation addresses climate-chemistry interaction associated with such increases in three aspects using observations as well as atmospheric chemistry and climate models. Ozone impact on climate is first evaluated by radiative forcing calculations due to observed ozone changes. It is found that a 10% increase in tropospheric ozone causes a radiative forcing of 0.17 Wm-2 using a fixed temperature (FT) method or 0.13 Wm-2 using a fixed dynamic heating (FDH) method, which is comparable to the radiative forcing 0.26 (FT) and -0.09 Wm-2 (FDH) caused by the stratospheric ozone depletion during the 1980s. Second, radiative forcing due to changes in ozone precursors is estimated. Ozone changes in response to a 20% reduction in surface NOx emission in six regions around the globe differ between regions. A maximum decrease in ozone column reaches 5% in southeast Asia and the central Atlantic Ocean, inducing a local radiative forcing of up to -0.1 Wm-2 in those regions. It indicates that surface NOx emission changes can potentially affect regional climate. Third, the effects of climate and climate changes on atmospheric chemistry are addressed with two studies. One study investigates the effects of global warming on methane and ozone, and another looks into cloud effects on photodissociation rate constants. Calculations based on the IPCC business-as-usual scenario indicate that by 2050, temperature and moisture increases can suppress methane and tropospheric ozone increases by 17% and 11%, respectively, in reference to the 1990 concentrations. The combined effects offset the global warming induced forcing 3.90 Wm -2 by -0.46 Wm-2. A one-dimensional study suggests that a typical cirrus cloud (τ = 2) can significantly increase J(O1D) and J(NO2) around the tropopause with a maximum of 21%. Geographical and seasonal

  20. Stratospheric ozone measurement with an infrared heterodyne spectrometer

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Kostiuk, T.; Mumma, M. J.; Buhl, D.; Kunde, V. G.; Brown, L. W.

    1978-01-01

    Measurements of a stratospheric ozone concentration profile are made by detecting infrared absorption lines with a heterodyne spectrometer. The infrared spectrometer is based on a line-by-line tunable CO2 lasers, a liquid-nitrogen cooled HgCdTe photomixer, and a 64-channel spectral line receiver. The infrared radiation from the source is mixed with local-oscillator radiation. The difference frequency signal in a bandwidth above and below the local-oscillator frequency is detected. The intensity in each sideband is found by subtracting sideband contributions. It is found that absolute total column density is 0.32 plus or minus 0.02 cm-atm with a peak mixing ratio at about 24 km. The (7,1,6)-(7,1,7) O3 line center frequency is identified as 1043.1772/cm. Future work will involve a number of ozone absorption lines and measurements of diurnal variation. Completely resolved stratospheric lines may be inverted to yield concentration profiles of trace constituents and stratospheric gases.

  1. 78 FR 78071 - Protection of Stratospheric Ozone: Adjustments to the Allowance System for Controlling HCFC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-24

    ... Deplete the Ozone Layer (Protocol). Under the Protocol and the Clean Air Act, total United States HCFC... about EPA's Stratospheric Ozone Protection regulations, the science of ozone layer depletion, and... Conditioning and Refrigeration Montreal Protocol Montreal Protocol on Substances That Deplete the Ozone...

  2. Nonlinear response of modelled stratospheric ozone to changes in greenhouse gases and ozone depleting substances in the recent past

    NASA Astrophysics Data System (ADS)

    Meul, S.; Oberländer-Hayn, S.; Abalichin, J.; Langematz, U.

    2015-06-01

    In the recent past, the evolution of stratospheric ozone (O3) was affected by both increasing ozone depleting substances (ODSs) and greenhouse gases (GHGs). The impact of the single forcings on O3 is well known. Interactions between the simultaneously increased GHG and ODS concentrations, however, can occur and lead to nonlinear O3 changes. In this study, we investigate if nonlinear processes have affected O3 changes between 1960 and 2000. This is done with an idealised set of time slice simulations with the chemistry-climate model EMAC. Due to nonlinearity the past ozone loss is diminished throughout the stratosphere, with a maximum reduction of 1.2 % at 3 hPa. The total ozone column loss between 1960 and 2000 that is mainly attributed to the ODS increase is mitigated in the extra-polar regions by up to 1.1 % due to nonlinear processes. A separation of the O3 changes into the contribution from chemistry and transport shows that nonlinear interactions occur in both. In the upper stratosphere a reduced efficiency of the ClOx-catalysed O3 loss chiefly causes the nonlinear O3 increase. An enhanced formation of halogen reservoir species through the reaction with methane (CH4) reduces the abundance of halogen radicals significantly. The temperature-induced deceleration of the O3 loss reaction rate in the Chapman cycle is reduced, which leads to a nonlinear O3 decrease and counteracts the increase due to ClOx. Nonlinear effects on the NOx abundance cause hemispheric asymmetric nonlinear changes of the O3 loss. Nonlinear changes in O3 transport occur in particular in the Southern Hemisphere (SH) during the months September to November. Here, the residual circulation is weakened in the lower stratosphere, which goes along with a reduced O3 transport from the tropics to high latitudes. Thus, O3 decreases in the SH polar region but increases in the SH midlatitudes. The existence of nonlinearities implies that future ozone change due to ODS decline slightly depends on the

  3. Development of a Climate Record of Tropospheric and Stratospheric Column Ozone from Satellite Remote Sensing: Evidence of an Early Recovery of Global Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Ziemke, Jerald R.; Chandra, Sushil

    2012-01-01

    Ozone data beginning October 2004 from the Aura Ozone Monitoring Instrument (OMI) and Aura Microwave Limb Sounder (MLS) are used to evaluate the accuracy of the Cloud Slicing technique in effort to develop long data records of tropospheric and stratospheric ozone and for studying their long-term changes. Using this technique, we have produced a 32-yr (1979-2010) long record of tropospheric and stratospheric column ozone from the combined Total Ozone Mapping Spectrometer (TOMS) and OMI. Analyses of these time series suggest that the quasi-biennial oscillation (QBO) is the dominant source of inter-annual variability of stratospheric ozone and is clearest in the Southern Hemisphere during the Aura time record with related inter-annual changes of 30- 40 Dobson Units. Tropospheric ozone for the long record also indicates a QBO signal in the tropics with peak-to-peak changes varying from 2 to 7 DU. The most important result from our study is that global stratospheric ozone indicates signature of a recovery occurring with ozone abundance now approaching the levels of year 1980 and earlier. The negative trends in stratospheric ozone in both hemispheres during the first 15 yr of the record are now positive over the last 15 yr and with nearly equal magnitudes. This turnaround in stratospheric ozone loss is occurring about 20 yr earlier than predicted by many chemistry climate models. This suggests that the Montreal Protocol which was first signed in 1987 as an international agreement to reduce ozone destroying substances is working well and perhaps better than anticipated.

  4. Stratospheric-Tropospheric Interaction and the 2002 Ozone Hole

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.

    2003-01-01

    The 2002 ozone hole was remarkable for its small size and early break-up. This small size resulted from a series of wave events over the course of the 2002 winter. The major event of the 2002 winter was the major warming in late September 2002. This warming resulted from an extremely strong wave event that propagated out of the troposphere, reversed the zonal mean flow, and warmed the polar vortex. This late-September event was the culmination of a series of large wave events which occurred over the course of the 2002 winter. These waves collectively warmed the vortex and decelerated the stratospheric flow. In this talk, we will trace the origin of these wave events, and we will also analyze the feedback of the large disruption of the stratospheric flow on the troposphere.

  5. Observations of Ozone-aerosol Correlated Behaviour in the Lower Stratosphere During the EASOE Campaign

    NASA Technical Reports Server (NTRS)

    Digirolamo, P.; Cacciani, M.; Disarra, A.; Fiocco, G.; Fua, D.; Joergensen, T. S.; Knudsen, B.; Larsen, N.

    1992-01-01

    The question of possible interactions between ozone and stratospheric aerosol has been open for a long time. Measurements carried out after the Mt. Agung and El Chicon eruptions showed evidence of negative correlations between the presence of volcanic stratospheric aerosols and ozone concentration. Evidence for negative correlations in the polar winter has been also found. It is only after the discovery of the Antarctic ozone hole that catalytic effects related to low temperature heterogeneous chemistry have become the object of much investigation, now extended to the role of volcanic aerosol in the ozone reduction. These phenomena can be the object of various interpretations, not mutually exclusive, including the effect of transport, diffuse radiation as well as heterogeneous chemistry. The present paper provides preliminary results of simultaneous measurements of ozone and aerosol, carried out at Thule, Greenland, during the winter 1991-92. The European Stratospheric Ozone Experiment (EASOE) was aimed at monitoring the winter Arctic stratosphere in order to obtain a deeper insight of the ozone destruction processes taking place in the polar regions. A large amount of aerosol was injected into the lower stratosphere by the recent eruption of Volcano Pinatubo. A lidar system, already operational in Thule since November 1990, has provided detailed measurements of the stratospheric aerosol concentration during EASOE. In the same period, a large number of ozonesondes were launched. Although no PSC formation was detected over Thule, the simultaneous measurement of the stratospheric aerosol and ozone profiles give the possibility to study interactions occurring in the stratosphere between these two constituents.

  6. Lidar Measurements of Stratospheric Ozone, Temperature and Aerosol During 1992 UARS Correlative Measurement Campaign

    NASA Technical Reports Server (NTRS)

    Mcgee, Thomas J.; Singh, Upendra N.; Gross, Michael; Heaps, William S.; Ferrare, Richard

    1992-01-01

    Measurements of stratospheric ozone, temperature, and aerosols were made by the NASA/GSFC mobile stratospheric lidar during the UARS (Upper Atmospheric Research Satellite) Correlative Measurement Campaign at the JPL-Table Mountain Facility in Feb. and Mar. 1992. Due to the presence of substantial amounts of residual volcanic aerosol from the eruption of Mt. Pinatubo, the GSFC lidar system was modified for an accurate measurement of ozone concentration in the stratosphere. While designed primarily for the measurement of stratospheric ozone, this lidar system was also used to measure middle atmosphere temperature and density from 30 to 65 km and stratospheric aerosol from 15 to 35 km. In the following sections, we will briefly describe and present some typical measurements made during this campaign. Stratospheric ozone, temperature, and aerosols profiles derived from data taken between 15 Feb. and 20 Mar., 1992 will be presented at the conference.

  7. North-south asymmetries of solar particle events in upper stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Maeda, K.; Heath, D. F.; Aruga, T.

    1984-01-01

    Stratospheric ozone depressions, following intense solar particle events (SPE) observed by the backscattered ultraviolet (BUV) experiment on the Nimbus-4 satellite, indicate the existence of distinct asymmetries between the Northern and Southern Hemispheres. These asymmetries are observed in the magnitude of the depressions above the 5-mb level, their temporal variations, and the spatial (i.e., latitude and longitude) dependence of these variations. Possible causes of asymmetries, shown by two events on August 4, 1972 and January 25, 1971, can be attributed to: (1) tilt of the interplanetary magnetic field (IMF) with respect to the earth's dipole magnetic field which influences the precipitation of energetic solar particles into the polar atmospheres; (2) differences in ozone chemistry caused by the large change in atmospheric temperature between summer and winter hemispheres; (3) seasonal differences of the stratosphere's dynamic states which are affected by upward propagating planetary waves in winter in contrast to the relatively undisturbed zonal flows in summer; and (4) topographic asymmetry between Northern and Southern Hemispheres. These effects are shown by three-dimensional plots of the events in geographic coordinates and by color contour plots of the stratospheric ozone distributions in geomagnetic and geographic polar coordinates, respectively.

  8. Stratospheric Sulfuric Acid and Black Carbon Aerosol Measured During POLARIS and its Role in Ozone Chemistry

    NASA Technical Reports Server (NTRS)

    Strawa, Anthony W.; Pueschel, R. F.; Drdla, K.; Verma, S.; Gore, Warren J. (Technical Monitor)

    1998-01-01

    Stratospheric aerosol can affect the environment in three ways. Sulfuric acid aerosol have been shown to act as sites for the reduction of reactive nitrogen and chlorine and as condensation sites to form Polar Stratospheric Clouds, under very cold conditions, which facilitate ozone depletion. Recently, modeling studies have suggested a link between BCA (Black Carbon Aerosol) and ozone chemistry. These studies suggest that HNO3, NO2, and O3 may be reduced heterogeneously on BCA particles. The ozone reaction converts ozone to oxygen molecules, while HNO3 and NO2 react to form NOx. Finally, a buildup of BCA could reduce the single-scatter albedo of aerosol below a value of 0.98, a critical value that has been postulated to change the effect of stratospheric aerosol from cooling to warming. Correlations between measured BCA amounts and aircraft usage have been reported. Attempts to link BCA to ozone chemistry and other stratospheric processes have been hindered by questions concerning the amount of BCA that exists in the stratosphere, the magnitude of reaction probabilities, and the scarcity of BCA measurements. The Ames Wire Impactors (AWI) participated in POLARIS as part of the complement of experiments on the NASA ER-2. One of our main objectives was to determine the amount of aerosol surface area, particularly BCA, available for reaction with stratospheric constituents and assess if possible, the importance of these reactions. The AWI collects aerosol and BCA particles on thin Palladium wires that are exposed to the ambient air in a controlled manner. The samples are returned to the laboratory for subsequent analysis. The product of the AWI analysis is the size, surface area, and volume distributions, morphology and elemental composition of aerosol and BCA. This paper presents results from our experiments during POLARIS and puts these measurements in the context of POLARIS and other missions in which we have participated. It describes modifications to the AWI data

  9. The effect of ozone depletion on the Southern Annular Mode and stratosphere-troposphere coupling

    NASA Astrophysics Data System (ADS)

    Dennison, Fraser W.; McDonald, Adrian J.; Morgenstern, Olaf

    2015-07-01

    The aim of this study is to investigate the influence of ozone depletion and recovery on the Southern Annular Mode (SAM) and stratosphere-troposphere coupling. Using the National Institute of Water and Atmospheric Research-United Kingdom Chemistry and Aerosols chemistry-climate model, we compare reference runs that include forcing due to greenhouse gases and ozone-depleting substances to sensitivity simulations in which ozone-depleting substances are fixed at their 1960 levels. We find that ozone depletion leads to an increased frequency of extreme anomalies and increased persistence of the SAM in the stratosphere as well as stronger, more persistent stratosphere-troposphere coupling. Currently, the stratosphere provides an appreciable amount of predictability to the troposphere on timescales of 1 or 2 months; however, we find that this effect reduces over time as stratospheric ozone recovers to preozone hole levels toward the latter part of this century.

  10. Chlorine monoxide radical, ozone, and hydrogen peroxide: stratospheric measurements by microwave limb sounding

    SciTech Connect

    Waters, J.W.; Hardy, J.C.; Jarnot, R.F.; Pickett, H.M.

    1981-10-02

    Profiles of stratospheric ozone and chlorine monoxide radical (ClO) were obtained from balloon measurements of atmospheric limb thermal emission at millimeter wavelengths. The ClO measurements, important for assessing the predicted depletion of stratospheric ozone by chlorine from industrial sources, are in close agreement with present theory. The predicted decrease of ClO at sunset was measured. A tentative value for the stratospheric abundance of hydrogen peroxide was also determined.

  11. Chlorine monoxide radical, ozone, and hydrogen peroxide - Stratospheric measurements by microwave limb sounding

    NASA Technical Reports Server (NTRS)

    Waters, J. W.; Hardy, J. C.; Jarnot, R. F.; Pickett, H. M.

    1981-01-01

    Profiles of stratospheric ozone and chlorine monoxide radical (ClO) have been obtained from balloon measurements of atmospheric limb thermal emission at millimeter wavelengths. The ClO measurements, important for assessing the predicted depletion of stratospheric ozone by chlorine from industrial sources, are in close agreement with present theory. The predicted decrease of ClO at sunset was measured. A tentative value for the stratospheric abundance of hydrogen peroxide was also determined.

  12. 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.

  13. Impact of cosmic rays on stratospheric chlorine chemistry and ozone depletion.

    PubMed

    Müller, Rolf

    2003-08-01

    Dissociation induced by cosmic rays of chlorofluorocarbons (CFC) and HCl on the surfaces of polar stratospheric clouds (PSC) has been suggested as playing a significant role in causing the ozone hole. However, observed stratospheric CFC distributions are inconsistent with a destruction of CFC on PSC surfaces and no significant correlation exists between ozone levels and cosmic-ray activity inside the polar regions. Model simulations indicate that this mechanism can have only a limited impact on chemical ozone loss and thus on the recovery of stratospheric ozone.

  14. Modeling Stratospheric Constituents: Reactive Species That Regulate Ozone

    NASA Technical Reports Server (NTRS)

    Salawitch, Ross J.

    2000-01-01

    Photochemical loss of stratospheric ozone occurs primarily by catalytic cycles whose rates are limited by the concentration of OH, HO2, NO2, ClO, and/or BrO as well as the concentration of either atomic oxygen or of ozone itself. Once the concentrations of these gases are established, the photochemical loss rate of O3 depends on the rate coefficient of only a handful of key reactions. We have developed a method for testing our understanding of stratospheric ozone photochemistry by comparing measured and modeled concentrations of reactive hydrogen, nitrogen, chlorine and bromine radicals using a photochemical steady state model constrained by observed concentrations of long-lived precursors (e.g., NO(y), Cl(y), Br(y), O3, H2O, CH4) and environmental parameters such as ozone column, reflectivity, and aerosol surface area. We will show based on analyses of observations obtained by aircraft, balloon, and satellite platforms during the POLARIS campaign that our overall understanding of the processes that regulate these radical species is very good. The most notable current discrepancies are the tendency to underestimate observed NO2 by 15 to 30% for air masses that experience near continuous solar illumination over a 24 hour period and the tendency to underestimate observed OH and H02 by about 10 to 20% during midday and by much larger amounts at high solar zenith angle (SZA > 85). Possible resolutions to these discrepancies will be discussed. This study was carried out in close collaboration with many members of the POLARIS science team.

  15. Multimodel Assessment of the Factors Driving Stratospheric Ozone Evolution over the 21st Century

    NASA Technical Reports Server (NTRS)

    Oman, L. D.; Plummer, D. A.; Waugh, D. W.; Austin, J.; Scinocca, J. F.; Douglass, A. R.; Salawitch, R. J.; Canty, T.; Akiyoshi, H.; Bekki, S.; Braesicke, P.; Butchart, N.; Chipperfield, M. P.; Cugnet, D.; Dhomse, S.; Eyring, V.; Frith, S.; Hardiman, S. C.; Kinnison, D. E.; Lamarque, J.-F.; Mancini, E.; Marchand, M.; Michou, M.; Morgenstern, O.; Nakamura, T.

    2010-01-01

    The evolution of stratospheric ozone from 1960 to 2100 is examined in simulations from 14 chemistry-climate models, driven by prescribed levels of halogens and greenhouse gases. There is general agreement among the models that total column ozone reached a minimum around year 2000 at all latitudes, projected to be followed by an increase over the first half of the 21st century. In the second half of the 21st century, ozone is projected to continue increasing, level off, or even decrease depending on the latitude. Separation into partial columns above and below 20 hPa reveals that these latitudinal differences are almost completely caused by differences in the model projections of ozone in the lower stratosphere. At all latitudes, upper stratospheric ozone increases throughout the 21st century and is projected to return to 1960 levels well before the end of the century, although there is a spread among models in the dates that ozone returns to specific historical values. We find decreasing halogens and declining upper atmospheric temperatures, driven by increasing greenhouse gases, contribute almost equally to increases in upper stratospheric ozone. In the tropical lower stratosphere, an increase in upwelling causes a steady decrease in ozone through the 21st century, and total column ozone does not return to 1960 levels in most of the models. In contrast, lower stratospheric and total column ozone in middle and high latitudes increases during the 21st century, returning to 1960 levels well before the end of the century in most models.

  16. Multimodel assessment of the factors driving stratospheric ozone evolution over the 21st century

    NASA Astrophysics Data System (ADS)

    Oman, L. D.; Plummer, D. A.; Waugh, D. W.; Austin, J.; Scinocca, J. F.; Douglass, A. R.; Salawitch, R. J.; Canty, T.; Akiyoshi, H.; Bekki, S.; Braesicke, P.; Butchart, N.; Chipperfield, M. P.; Cugnet, D.; Dhomse, S.; Eyring, V.; Frith, S.; Hardiman, S. C.; Kinnison, D. E.; Lamarque, J.-F.; Mancini, E.; Marchand, M.; Michou, M.; Morgenstern, O.; Nakamura, T.; Nielsen, J. E.; Olivié, D.; Pitari, G.; Pyle, J.; Rozanov, E.; Shepherd, T. G.; Shibata, K.; Stolarski, R. S.; TeyssèDre, H.; Tian, W.; Yamashita, Y.; Ziemke, J. R.

    2010-12-01

    The evolution of stratospheric ozone from 1960 to 2100 is examined in simulations from 14 chemistry-climate models, driven by prescribed levels of halogens and greenhouse gases. There is general agreement among the models that total column ozone reached a minimum around year 2000 at all latitudes, projected to be followed by an increase over the first half of the 21st century. In the second half of the 21st century, ozone is projected to continue increasing, level off, or even decrease depending on the latitude. Separation into partial columns above and below 20 hPa reveals that these latitudinal differences are almost completely caused by differences in the model projections of ozone in the lower stratosphere. At all latitudes, upper stratospheric ozone increases throughout the 21st century and is projected to return to 1960 levels well before the end of the century, although there is a spread among models in the dates that ozone returns to specific historical values. We find decreasing halogens and declining upper atmospheric temperatures, driven by increasing greenhouse gases, contribute almost equally to increases in upper stratospheric ozone. In the tropical lower stratosphere, an increase in upwelling causes a steady decrease in ozone through the 21st century, and total column ozone does not return to 1960 levels in most of the models. In contrast, lower stratospheric and total column ozone in middle and high latitudes increases during the 21st century, returning to 1960 levels well before the end of the century in most models.

  17. The Effect of Transport and Circulation Differences on Stratospheric Ozone Recovery in Two 35-year Three-dimensional Simulations

    NASA Technical Reports Server (NTRS)

    Bhartia, P. K. (Technical Monitor); Strahan, Susan; Douglass, Anne

    2002-01-01

    The NASA Global Modeling Initiative (GMI) has completed two 35-year simulations with WMO future baseline boundary conditions that simulate increasing N2O and CH4 emissions and decreasing organic chlorine and bromine emissions. Simulations were done with the GMI offline chemistry and transport model using 1) 1 year of winds from the Finite-Volume General Circulation Model (FV-GCM), repeated for the 35 years, and 2) 1 year of winds from the Finite-Volume Data Assimilation System (FV-DAS), repeated for 35-years. The simulations have full stratospheric chemistry. To understand differences in simulated ozone recoveries, basic transport and circulation differences between these models are evaluated. The distribution of mean age of stratospheric air in the FV-GCM run agrees well with observations in the lower stratosphere but the FV-DAS ages are generally too low. This implies circulation and mixing differences that will affect the distributions of other trace species such as CH4, NO, and the organic halogens, all of which are responding to changing boundary conditions and are involved in ozone loss. Realism of model transport is evaluated, with particular attention given to regions and seasons where ozone recovery is expected. Preliminary results indicate increasing ozone trends in the lowermost stratosphere in summer and in the Antarctic and Arctic lower stratosphere in winter and spring.

  18. SWIFT: Semi-empirical and numerically efficient stratospheric ozone chemistry for global climate models

    NASA Astrophysics Data System (ADS)

    Kreyling, Daniel; Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

    2015-04-01

    The SWIFT model is a fast yet accurate chemistry scheme for calculating the chemistry of stratospheric ozone. It is mainly intended for use in Global Climate Models (GCMs), Chemistry Climate Models (CCMs) and Earth System Models (ESMs). For computing time reasons these models often do not employ full stratospheric chemistry modules, but use prescribed ozone instead. This can lead to insufficient representation between stratosphere and troposphere. The SWIFT stratospheric ozone chemistry model, focuses on the major reaction mechanisms of ozone production and loss in order to reduce the computational costs. SWIFT consists of two sub-models. 1) Inside the polar vortex, the model calculates polar vortex averaged ozone loss by solving a set of coupled differential equations for the key species in polar ozone chemistry. 2) The extra-polar regime, which this poster is going to focus on. Outside the polar vortex, the complex system of differential equations of a full stratospheric chemistry model is replaced by an explicit algebraic polynomial, which can be solved in a fraction of the time needed by the full scale model. The approach, which is used to construct the polynomial, is also referred to as repro-modeling and has been successfully applied to chemical models (Turanyi (1993), Lowe & Tomlin (2000)). The procedure uses data from the Lagrangian stratospheric chemistry and transport model ATLAS and yields one high-order polynomial for global ozone loss and production rates over 24h per month. The stratospheric ozone change rates can be sufficiently described by 9 variables. Latitude, altitude, temperature, the overhead ozone abundance, 4 mixing ratios of ozone depleting chemical families (chlorine, bromine, nitrogen-oxides and hydrogen-oxides) and the ozone concentrations itself. The ozone change rates in the lower stratosphere as a function of these 9 variables yield a sufficiently compact 9-D hyper-surface, which we can approximate with a polynomial. In the upper

  19. Chlorofluorocarbon production scenarios: possible changes to stratospheric ozone

    SciTech Connect

    Wuebbles, D.J.; Tarp, R.L.; Nold, A.; Wood, W.P.

    1981-01-01

    As one aspect of the regulatory process, the Environmental Protection Agency has derived a series of scenarios for future atmospheric emission rates of the chlorofluorocarbons CFCl/sub 3/ (also referred to as F-11), CF/sub 2/Cl/sub 2/ (F-12), CCl/sub 2/FCClF/sub 2/(F-113), CClF/sub 2/CClF/sub 2/(F-114), and CClF/sub 2/CF/sub 3/ (F-115). These scenarios are based on potential industrial production and commercial applications, and the eventual release of these chemicals into the atmosphere. In this study, the potential effect on stratospheric ozone resulting from future chlorofluorocarbon emissions as suggested by these scenarios is examined. Assessments are based upon model calculations using the one-dimensional coupled transport and chemical kinetics model of the troposphere and stratosphere developed at Lawrence Livermore National Laboratory. The change in total ozone column calculated for the seven scenarios as a function of time is given. (JGB)

  20. Effects of Zonal Wind on Stratospheric Ozone Variations over Nigeria

    NASA Astrophysics Data System (ADS)

    Chidinma Okoro, Eucharia,

    2016-07-01

    The effects of zonal wind on stratospheric ozone variation over Nigeria have been studied. The areas covered in this study include; Maiduguri, Ikeja, Port-Harcourt, Calabar, Makurdi, Ilorin, Akure, Yola, Minna, Jos, Kano and Enugu in Nigeria, from 1986 to 2008. Zonal wind was computed from the iso-velocity map employing MATLAB software. The mean monthly variations of AAM and LOD at pressure levels of 20, 30 and 50 mb in the atmosphere depict a trend of maximum amplitude between April and September, and minimum amplitude between December and March. The trend observed in seasonal variation of O3 column data in the low latitude had maximum amount from May through August and minimum values from December through February. The mean monthly maximum O3 concentrations was found to be 284.70 Du (Kano) occurring in May 1989 while, an average monthly minimum O3 concentration was found to be 235.60 Du (Port-Harcourt and Calabar) occurring in January 1998. It has been established in this study that, the variation in atmospheric angular momentum (AAM) caused by variation of the universal time or length of day (LOD) transfer ozone (O3) by means of zonal wind from the upper troposphere to the lower stratosphere in the stations understudy. The strong effect of the pressure levels of the atmosphere on O3 variation could be attributed to its effect on the AAM and LOD. Variation in the LOD is significant in the tropics, suggesting that, the effects of the extra-tropical suction pump (ETSP) action is not the only driver responsible for O3 transportation from the tropics to extra-tropical zones. Consequently, these findings lead to a deduction that weather pattern alteration observed due to these changes could lead to climate change. Keywords: ozone variations; dynamical processes; harmattan wind; ETSP; and climatic variability

  1. Investigations of Stratosphere-Troposphere Exchange of Ozone Derived From MLS Observations

    NASA Astrophysics Data System (ADS)

    Olsen, M. A.; Schoeberl, M. R.; Ziemke, J. R.

    2006-12-01

    Daily high-resolution maps of stratospheric ozone have been constructed using observations by MLS combined with trajectory information. These fields are used to determine the extratropical stratosphere- troposphere exchange (STE) of ozone for the year 2005 using two diagnostic methods. The resulting two annual estimates compare well with past model- and observational-based estimates. Initial analyses of the seasonal characteristics indicate that significant STE of ozone in the polar regions occurs only during spring and early summer. We also examine evidence that the Antarctic ozone hole is responsible for a rapid decrease in the rate of ozone STE during the SH spring. Subtracting the high-resolution stratospheric ozone from OMI total column measurements creates a high- resolution tropospheric ozone residual (HTOR) product. The HTOR fields are compared to the spatial distribution of the ozone STE. We show that the mean tropospheric ozone maxima tend to occur near locations of significant ozone STE. This suggests that ozone transported from the stratosphere may be responsible for a significant fraction of the mean tropospheric ozone maxima.

  2. Influence of a solar proton event on stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Heath, D. F.; Krueger, A. J.; Crutzen, P. J.

    1976-01-01

    Ozone depletion in the stratosphere associated with the solar proton event of August 4, 1972, was observed with the backscattered ultraviolet experiment on the Nimbus 4 satellite. An abrupt ozone decrease in the 75-80 deg N zone of about 0.002 atm-cm above 4 mb was observed to persist throughout the month of August. A decrease was noted in the 55-65 deg N zone on days 219 and 220, but recovery occurred on day 221. Thereafter, a more gradual decrease was observed. The equatorial zone also showed gradual decrease after day 218, but these were not uniquely distinguished from seasonal variations. The observed change in total ozone following the event was -0.003 atm-cm for the 75-80 deg N zone, corresponding to a 1.3 percent reduction in the 0.305 atm-cm zonal average, but within the 0.019 atm-cm standard deviation. Above the 10 mb surface in the 75-80 deg N zone however, a decrease of 0.004 atm-cm may be compared with a standard deviation of 0.001 atm-cm.

  3. Simulating the impact of emissions of brominated very short lived substances on past stratospheric ozone trends

    NASA Astrophysics Data System (ADS)

    Sinnhuber, Björn-Martin; Meul, Stefanie

    2015-04-01

    Bromine from very short lived substances (VSLS), primarily from natural oceanic sources, contributes substantially to the stratospheric bromine loading. This source of stratospheric bromine has so far been ignored in most chemistry climate model calculations of stratospheric ozone trends. Here we present a transient simulation with the chemistry climate model EMAC for the period 1960-2005 including emissions of the five brominated VSLS CHBr3, CH2Br2, CH2BrCl, CHBrCl2, and CHBr2Cl. The emissions lead to a realistic stratospheric bromine loading of about 20 pptv for present-day conditions. Comparison with a standard model simulation without VSLS shows large differences in modeled ozone in the extratropical lowermost stratosphere and in the troposphere. Differences in ozone maximize in the Antarctic Ozone Hole, resulting in more than 20% less ozone when VSLS are included. Even though the emissions of VSLS are assumed to be constant in time, the model simulation with VSLS included shows a much larger ozone decrease in the lowermost stratosphere during the 1979-1995 period and a faster ozone increase during 1996-2005, in better agreement with observed ozone trends than the standard simulation without VSLS emissions.

  4. Scientific Assessment of Stratospheric Ozone: 1989, volume 2. Appendix: AFEAS Report

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The results are presented of the Alternative Fluorocarbon Environmental Acceptability Study (AFEAS), which was organized to evaluate the potential effects on the environment of alternate compounds targeted to replace fully halogenated chlorofluorocarbons (CFCs). All relevant current scientific information to determine the environmental acceptability of the alternative fluorocarbons. Special emphasis was placed on: the potential of the compounds to affect stratospheric ozone; their potential to affect tropospheric ozone; their potential to contribute to model calculated global warming; the atmospheric degradation mechanisms of the compounds, in order to identify their products; and the potential environmental effects of the decomposition products. The alternative compounds to be studied were hydrofluorocarbons (HFCs) with one or two carbon atoms and one or more each of fluorine and hydrogen.

  5. Sensitivity of Lower Stratospheric Assimilated Ozone on Error Covariance Modeling and Data Selection

    NASA Technical Reports Server (NTRS)

    Stajner, Ivanka; Rood, Richard B.; Winslow, Nathan; Wargan, Krzysztof; Pawson, Steven

    2002-01-01

    Assimilated ozone is produced at the NASA/Goddard Data Assimilation Office by blending ozone retrieved from the Solar Backscatter UltraViolet/2 (SBUV/2) instrument and the Earth Probe Total Ozone Mapping Spectrometer (EP TOMS) measurements into an off-line transport model. The current system tends to overestimate the amount of lower stratospheric ozone. This is a region where ozone plays a key role in the forcing of climate. A biased ozone field in this region will adversely impact calculations of the stratosphere-troposphere exchange and, when used as a first guess in retrievals, the values determined from satellite observations. Since these are all important applications of assimilated ozone products, effort is being directed towards reducing this bias. The SBUV ozone data have a coarse vertical resolution with increased uncertainty below the ozone maximum, and TOMS provides only total ozone columns. Thus, the assimilated ozone in the lower stratosphere, and its vertical distribution in particular, are only weakly constrained by the incoming SBUV and TOMS data. Consequently, the assimilated ozone distribution should be sensitive to changes in inputs to the statistical analysis scheme. Accordingly, the sensitivity of the assimilated lower stratospheric ozone fields to changes in the TOMS error-covariance modeling and the SBUV data selection has been investigated. The use of a spatially correlated TOMS error covariance model led to improvements in the product. However, withholding the SBUV/2 data for the layer between 63 and 126 hPa typically degraded the product, a result which vindicates the use of this layer ozone product, despite its known errors. These efforts to improve the lower stratospheric distribution will be extended to include a more advanced forecast error covariance model, and by assimilating ozone products from new instruments on Envisat and EOS Aura.

  6. 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.

  7. Export of Ozone-Poor Air from the Lower Tropical Stratosphere to Mid-latitudes

    NASA Astrophysics Data System (ADS)

    Spackman, J. R.; Weinstock, E. M.; Anderson, J. G.

    2002-05-01

    Analysis of ozonesonde profiles shows a decline in ozone of 7 to 9%/decade during the past 20 to 30 years in the northern mid-latitude lower stratosphere [Logan et al., 1999], exposing the large population at these latitudes to increased health risks. Heterogeneous processing leading to halogen-catalyzed ozone loss is not expected to occur in the mid-latitude lower stratosphere because in situ measurements indicate the air is consistently undersaturated and low in ClO in this region [Smith et al., 2001]. Furthermore, in situ measurements acquired aboard the NASA ER-2 aircraft during SOLVE (SAGE III Ozone Loss and Validation Experiment) suggest that equatorward mixing of ozone-depleted air from the Arctic vortex does not contribute significantly to declines in mid-latitude lower stratospheric ozone. Instead, tracer-tracer correlations from SOLVE indicate that rapid isentropic transport from the lower tropical stratosphere coupled with diabatic descent in mid-latitudes delivers very young, ozone-poor air to the lowermost stratosphere (θ < 380 K) during northern winter. Given this result, we hypothesize that the seasonal and interannual variability in the strength of this transport from the lower tropical stratosphere modulates mid-latitude lower stratospheric ozone. We investigate methods of using in situ observations to test this hypothesis. Logan, J.A., et al., Trends in the vertical distribution of ozone: A comparison of two analyses of ozonesonde data, Journal of Geophysical Research, 104, 26373-26399, 1999. Smith, J.B., et al., Mechanisms for midlatitude ozone loss: Heterogeneous chemistry in the lowermost stratosphere?, Journal of Geophysical Research, 106, 1297-1309, 2001.

  8. Altitude dependence of stratospheric ozone trends based on Nimbus 7 SBUV data

    NASA Astrophysics Data System (ADS)

    Hood, Lon L.; McPeters, Richard D.; McCormack, John P.; Flynn, Lawrence E.; Hollandsworth, Stacey M.; Gleason, James F.

    1993-12-01

    A multiple regression statistical model is applied to estimate the altitude, latitude, and seasonal dependences of stratospheric ozone trends using 11.5 years of Nimbus 7 SBUV data for the period November 1978 to June 1990. In the upper stratosphere, the derived trends agree in both latitude dependence and approximate amplitude with published predictions from stratospheric models that consider gas-phase chemical processes together with the observed ˜0.1 ppbV per year increase in tropospheric chlorine. The dominant contribution to column ozone trends occurs in the lower stratosphere where significant negative trends are present at latitudes >20° in both hemispheres. The observed latitude dependence is qualitatively consistent with model predictions that include the effects of heterogeneous chemical ozone losses on lower stratospheric aerosols.

  9. Altitude dependence of stratospheric ozone trends based on Nimbus 7 SBUV data

    NASA Technical Reports Server (NTRS)

    Hood, Lon L.; Mcpeters, Richard D.; Mccormack, John P.; Flynn, Lawrence E.; Hollandsworth, Stacey M.; Gleason, James F.

    1993-01-01

    A multiple regression statistical model is applied to estimate the altitude, latitude, and seasonal dependences of stratospheric ozone trends using 11.5 years of Nimbus 7 SBUV data for the period November 1978 to June 1990. In the upper stratosphere, the derived trends agree in both latitude dependence and approximate amplitude with published predictions from stratospheric models that consider gas-phase chemical processes together with the observed approx. 0.1 ppbV per year increase in tropospheric chlorine. The dominant contribution to column ozone trends occurs in the lower stratosphere where significant negative trends are present at latitudes greater than 20 deg in both hemispheres. The observed latitude dependence is qualitatively consistent with model predictions that include the effects of heterogeneous chemical ozone losses on lower stratospheric aerosols.

  10. A Global Climatology of Tropospheric and Stratospheric Ozone Derived from Aura OMI and MLS Measurements

    NASA Technical Reports Server (NTRS)

    Ziemke, J.R.; Chandra, S.; Labow, G.; Bhartia, P. K.; Froidevaux, L.; Witte, J. C.

    2011-01-01

    A global climatology of tropospheric and stratospheric column ozone is derived by combining six years of Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone measurements for the period October 2004 through December 2010. The OMI/MLS tropospheric ozone climatology exhibits large temporal and spatial variability which includes ozone accumulation zones in the tropical south Atlantic year-round and in the subtropical Mediterranean! Asia region in summer months. High levels of tropospheric ozone in the northern hemisphere also persist in mid-latitudes over the eastern North American and Asian continents extending eastward over the Pacific Ocean. For stratospheric ozone climatology from MLS, largest ozone abundance lies in the northern hemisphere in the latitude range 70degN-80degN in February-April and in the southern hemisphere around 40degS-50degS during months August-October. The largest stratospheric ozone abundances in the northern hemisphere lie over North America and eastern Asia extending eastward across the Pacific Ocean and in the southern hemisphere south of Australia extending eastward across the dateline. With the advent of many newly developing 3D chemistry and transport models it is advantageous to have such a dataset for evaluating the performance of the models in relation to dynamical and photochemical processes controlling the ozone distributions in the troposphere and stratosphere.

  11. The features of ozone quasi-biennial oscillation in tropical stratosphere and its numerical simulation

    NASA Astrophysics Data System (ADS)

    Chen, Y. J.; Zheng, B.; Zhang, H.

    The interannual variation of the vertical distribiltion of ozone in the tropical stratosphere and its quasi-biennial oscillation (QBO) is analyzed Using HALOE data. The results are compared with the wind QBO. A numerical experiment is carried out to study the effects of wind QBO on the distribution, and variation OF ozone in the stratosphere by using the NCAR interactive chemical, dynamical, and radiative two-dimensional model (SOCRATES). Data analysis shows that the location of the maximum ozone mixing ratio in the stratosphere changes in the meridional and vertical directions, and assumes a quasi-biennial period, The meridional and vertical motion of the maximum mixing ratio leads to a QBO of column ozone and its hemispheric asymmetry. The QBO of the location of the maximum is closely connected with the zonal wind QBO. The data analysis also shows that in the tropical region, the phase of the QBO For ozone density changes many times with height. Numerical simulation shows that the meridional circulation induced by the wind QBO includes three pairs of cells in the stratosphere, which have hemispheric symmetry. The transport of ozone by the induced meridional circulation in various latitudes and heights is the main dynamic cause for the ozone QBO. Cells of the induced circulation in the middle stratosphere (25-35 km) play an important role in producing the ozone QBO.

  12. The features of ozone quasi—biennial oscillation in tropical stratosphere and its numerical simulation

    NASA Astrophysics Data System (ADS)

    Yucjuan, Chen; Bin, Zheng; Hong, Zhang

    2002-09-01

    The inlcrunnual variation of the vertical distribution of ozone in the tropical stratosphere and its quasi—biennial oscillation (QBO) is analyzed using HALOE data. The results are compared with the wind QBO. A numerical experiment is carried out to study the effects of wind QBO on the distribution, and variation of ozone in the stratosphere by using (he NCAR interactive chemical, dynamical, and radiative two—dimensional model (SOCRATES). Data analysis shows that the location of the maximum ozone mixing ratio in the stratosphere changes in the meridional and vertical directions, and assumes a quasi—biennial period. The meridional and vertical motion of the maximum mixing ratio leads to a QBO of column ozone and its hemispheric asymmetry. The QBO of the location of the maximum is closely connected with the zonal wind QBO. The data analysis also shows that in the tropical region, the phase of the QBO for ozone density changes many times with height. Numerical simulation shows that the meridional circulation induced by the wind QBO includes three pairs of cells in the stratosphere, which have hemispheric symmetry. The transport of ozone by the induced meridional circulation in various latitudes and heights is the main dynamic cause for the ozone QBO. Cells of the induced circulation in the middle stratosphere (25-35 km) play an important role in producing the ozone QBO.

  13. Electrochemical concentration cell ozone soundings at two sites during the Stratospheric Ozone Intercomparison Campaign

    NASA Astrophysics Data System (ADS)

    Barnes, Robert A.; Torres, Arnold L.

    1995-05-01

    The Stratospheric Ozone Intercomparison Campaign (STOIC) was designed to compare proposed instruments for the Network for the Detection of Stratospheric Change (NDSC) with established measurement techniques. Ground-based measurements were conducted at Table Mountain, California (34.4°N, 117.7°W), and rocket profiles were made at San Nicolas Island, California (33.3°N, 119.5°W). In an effort to estimate site-to-site differences during the intercomparison, daily soundings were made with balloon-borne electrochemical concentration cell (ECC) ozonesondes at the two sites. Comparisons have been made of the mean values for the soundings at each site. The soundings showed small temperature differences between the two sites with the nighttime Table Mountain measurements up to 2°K cooler than the daytime San Nicolas Island temperatures. Day/night temperature corrections based on the emissivity and absorptivity of the thermistors in the balloon instruments can account for these apparent temperature differences. Ozone partial pressure profiles from the ECCs have been used to estimate atmospheric ozone variability during STOIC. Above 20 km, the lowest altitude for the STOIC comparisons, the average data sets from both sites showed standard deviations that were at or below the estimated 5-6% profile-to-profile repeatability for the ozonesondes. This indicates that atmospheric ozone variability was only of the order of a few percent above 20 km during the 2 weeks of the STOIC campaign. Above 20 km the ozone partial pressures over the Table Mountain site averaged 2.0% lower than over San Nicolas Island.

  14. 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.

  15. Stratospheric ozone loss, ultraviolet effects and action spectroscopy

    NASA Astrophysics Data System (ADS)

    Coohill, Thomas P.

    The major effect of stratospheric ozone loss will be an increase in the amount of ultraviolet radiation reaching the ground. This increase will be entirely contained within the UV-B (290-320nm). How this will impact life on Earth will be determined by the UV-B photobiology of exposed organisms, including humans. One of the analytical methods useful in estimating these effects is Action Spectroscopy (biological effect as a function of wavelength). Carefully constructed action spectra will allow us to partially predict the increase in bio-effect due to additional UV exposure. What effect this has on the organism and the system in which the organism resides is of paramount importance. Suitable action spectra already exist for human skin cancer, human cell mutation and killing, and for one immune response. Comprehensive and widely applicable action spectra for terrestrial and aquatic plant responses are being generated but are not yet suitable for extensive analysis. There is little data available for animals, other than those experiments completed in the laboratory as model systems for human studies. Some polychromatic action spectra have proven useful in determining the possible impact of ozone loss on biological systems. The pitfalls and limits of this approach will be addressed.

  16. Effects of energetic particles precipitation on stratospheric ozone in the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Zossi de Artigas, Marta; Zotto, Elda M.; Mansilla, Gustavo A.; Fernandez de Campra, Patricia

    2016-11-01

    Measurements from TOMS and UARS-HALOE are used to estimate the effects of energetic particle precipitation (EPP) over the stratosphere during two geomagnetic storms occurred in November of the years 2003 and 2004. The EPP couples the solar wind to the Earth's atmosphere and indirectly to the Earth's climate. Due to particle precipitation, the ionization and dissociation increase, and create odd nitrogen (NOx) and odd hydrogen (HOx) in the upper atmosphere, which can affect ozone chemistry. In this paper, statistically significant variation in total ozone content at middle latitudes of the Southern Hemisphere is observed. The variations depend on the intensity of geomagnetic disturbances and the geomagnetic longitude. A significant variation in NOx concentration at altitudes from 30 to 50 km is observed from the profiles analysis.

  17. 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.

  18. Chemical Depletion of Lower Stratospheric Ozone in the 1992-1993 Northern Winter Vortex

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Froidevaux, L.; Waters, J. W.; Zurek, R. W.; Read, W. G.; Elson, L. S.; Kumer, J. B.; Mergenthaler, J. L.; Roche, A. E.; O'Neill, A.; Harwood, R. S.; MacKenzie, I.; Swinbank, R.

    1994-01-01

    Satellite observations of ozone and chlorine monoxide in the Arctic lower stratosphere during winter 1992-1993 are compared with observations during other winters, observations of long-lived tracers and the evolution of the polar vortex. Chlorine in the lower stratospheric vortex during February 1993 was mostly in chemically reactive forms.

  19. Stratospheric ozone time series analysis using dynamical linear models

    NASA Astrophysics Data System (ADS)

    Laine, Marko; Kyrölä, Erkki

    2013-04-01

    We describe a hierarchical statistical state space model for ozone profile time series. The time series are from satellite measurements by the SAGE II and GOMOS instruments spanning years 1984-2012. The original data sets are combined and gridded monthly using 10 degree latitude bands, and covering 20-60 km with 1 km vertical spacing. Model components include level, trend, seasonal effect with solar activity, and quasi biennial oscillations as proxy variables. A typical feature of an atmospheric time series is that they are not stationary but exhibit both slowly varying and abrupt changes in the distributional properties. These are caused by external forcing such as changes in the solar activity or volcanic eruptions. Further, the data sampling is often nonuniform, there are data gaps, and the uncertainty of the observations can vary. When observations are combined from various sources there will be instrument and retrieval method related biases. The differences in sampling lead also to uncertainties. Standard classical ARIMA type of statistical time series methods are mostly useless for atmospheric data. A more general approach makes use of dynamical linear models and Kalman filter type of sequential algorithms. These state space models assume a linear relationship between the unknown state of the system and the observations and for the process evolution of the hidden states. They are still flexible enough to model both smooth trends and sudden changes. The above mentioned methodological challenges are discussed, together with analysis of change points in trends related to recovery of stratospheric ozone. This work is part of the ESA SPIN and ozone CCI projects.

  20. 77 FR 16988 - Protection of Stratospheric Ozone: Amendment to HFO-1234yf SNAP Rule for Motor Vehicle Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-23

    ... procedure, Air pollution control, Reporting and recordkeeping requirements, Stratospheric ozone layer. Dated... AGENCY 40 CFR Part 82 RIN 2060-AR20 Protection of Stratospheric Ozone: Amendment to HFO-1234yf SNAP Rule... substitute for ozone- depleting substances (ODSs) in the motor vehicle air conditioning end- use within...

  1. Correlative Stratospheric Ozone Measurements with the Airborne UV DIAL System during TOTE/VOTE

    NASA Technical Reports Server (NTRS)

    Grant, William B.; Fenn, Marta A.; Browell, Edward V.; McGee, Thomas J.; Singh, Upendra N.; Gross, Michael R.; McDermid, I. Stuart; Froidevaux, Lucien; Wang, Pi-Huang

    1998-01-01

    The airborne UV differential absorption lidar (DIAL) system participated in the Tropical Ozone Transport Experiment/Vortex Ozone Transport Experiment (TOTE/VOTE) in late 1995/early 1996. This mission afforded the opportunity to compare the DIAL system's stratospheric ozone measuring capability with other remote-sensing instruments through correlative measurements over a latitude range from the tropics to the Arctic. These instruments included ground-based DIAL and space-based stratospheric instruments: HALOE; MLS; and SAGE II. The ozone profiles generally agreed within random error estimates for the various instruments in the middle of the profiles in the tropics, but regions of significant systematic differences, especially near or below the tropopause or at the higher altitudes were also found. The comparisons strongly suggest that the airborne UV DIAL system can play a valuable role as a mobile lower-stratospheric ozone validation instrument.

  2. Stratospheric ozone variations in the equatorial region as seen in Stratiospheric Aerosol and Gas Experiment data

    SciTech Connect

    Shiotani, M.; Hasebe, F. |

    1994-07-01

    An analysis is made of equatorial ozone variations for 5 years, 1984-1989, using the ozone profile data derived from the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument. Attention is focused on the annual cycle and also on interannual variability, particularly the quasi-biennial oscillation (QBO) and El Nino-Southern Oscillation (ENSO) variations in the lower stratosphere, where the largest contribution to total column ozone takes place. The annual variation in zonal mean total ozone around the equator is composed of symmetric and asymmetric modes with respect to the equator, with maximum contributions being around 19 km for the symmetric mode and around 25 km for the asymmetric mode. The persistent zonal wavenumber 1 structure observed by the total ozone mapping spectrometer over the equator is almost missing in the SAGE-derived column amounts integrated in the stratosphere, suggesting a significant contribution from tropospheric ozone. Interannual variations in the equatorial ozone are dominated by the QBO above 20 km and the ENSO-related variation below 20 km. The ozone QBO is characterized by zonally uniform phase changes in association with the zonal wind QBO in the equatorial lower stratosphere. The ENSO-related ozone variation consists of both the east-west vacillation and the zonally uniform phase variation. During the El Nino event, the east-west contrast with positive (negative) deviations in the eastern (western) hemisphere is conspicuous, while the decreasing tendency of the zonal mean values is maximum at the same time.

  3. Stratospheric ozone variations in the equatorial region as seen in Stratiospheric Aerosol and Gas Experiment data

    NASA Technical Reports Server (NTRS)

    Shiotani, Masato; Hasebe, Fumio

    1994-01-01

    An analysis is made of equatorial ozone variations for 5 years, 1984-1989, using the ozone profile data derived from the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument. Attention is focused on the annual cycle and also on interannual variability, particularly the quasi-biennial oscillation (QBO) and El Nino-Southern Oscillation (ENSO) variations in the lower stratosphere, where the largest contribution to total column ozone takes place. The annual variation in zonal mean total ozone around the equator is composed of symmetric and asymmetric modes with respect to the equator, with maximum contributions being around 19 km for the symmetric mode and around 25 km for the asymmetric mode. The persistent zonal wavenumber 1 structure observed by the total ozone mapping spectrometer over the equator is almost missing in the SAGE-derived column amounts integrated in the stratosphere, suggesting a significant contribution from tropospheric ozone. Interannual variations in the equatorial ozone are dominated by the QBO above 20 km and the ENSO-related variation below 20 km. The ozone QBO is characterized by zonally uniform phase changes in association with the zonal wind QBO in the equatorial lower stratosphere. The ENSO-related ozone variation consists of both the east-west vacillation and the zonally uniform phase variation. During the El Nino event, the east-west contrast with positive (negative) deviations in the eastern (western) hemisphere is conspicuous, while the decreasing tendency of the zonal mean values is maximum at the same time.

  4. Investigations of Stratosphere-Troposphere Exchange of Ozone Derived From MLS Observations

    NASA Technical Reports Server (NTRS)

    Olsen, Mark A.; Schoeberl, Mark R.; Ziemke, Jerry R.

    2006-01-01

    Daily high-resolution maps of stratospheric ozone have been constructed using observations by MLS combined with trajectory information. These fields are used to determine the extratropical stratosphere-troposphere exchange (STE) of ozone for the year 2005 using two diagnostic methods. The resulting two annual estimates compare well with past model- and observational-based estimates. Initial analyses of the seasonal characteristics indicate that significant STE of ozone in the polar regions occurs only during spring and early summer. We also examine evidence that the Antarctic ozone hole is responsible for a rapid decrease in the rate of ozone STE during the SH spring. Subtracting the high-resolution stratospheric ozone fiom OMI total column measurements creates a high-resolution tropospheric ozone residual (HTOR) product. The HTOR fields are compared to the spatial distribution of the ozone STE. We show that the mean tropospheric ozone maxima tend to occur near locations of significant ozone STE. This suggests that STE may be responsible for a significant fraction of many mean tropospheric ozone anomalies.

  5. Fiber-Optic Coupled Lidar Receiver System to Measure Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Harper, David Brent; Elsayed-Ali, Hani

    1998-01-01

    The measurement of ozone in the atmosphere has become increasingly important over the past two decades. Significant increases of ozone concentrations in the lower atmosphere, or troposphere, and decreases in the upper atmosphere, or stratosphere, have been attributed to man-made causes. High ozone concentrations in the troposphere pose a health hazard to plants and animals and can add to global warming. On the other hand, ozone in the stratosphere serves as a protective barrier against strong ultraviolet (UV) radiation from the sun. Man-made CFC's (chlorofluorocarbons) act as a catalyst with a free oxygen atom and an ozone molecule to produce two oxygen molecules therefore depleting the protective layer of ozone in the stratosphere. The beneficial and harmful effects of ozone require the study of ozone creation and destruction processes in the atmosphere. Therefore, to provide an accurate model of these processes, an ozone lidar system must be able to be used frequently with as large a measurement range as possible. Various methods can be used to measure atmospheric ozone concentrations. These include different airborne and balloon measurements, solar occulation satellite techniques, and the use of lasers in lidar (high detection and ranging,) systems to probe the atmosphere. Typical devices such as weather balloons can only measure within the direct vicinity of the instrument and are therefore used infrequently. Satellites use solar occulation techniques that yield low horizontal and vertical resolution column densities of ozone.

  6. Evaluation of Upper-Tropospheric and Lower-Stratospheric Ozone Profiles from a Global Ozone Data Assimilation System

    NASA Technical Reports Server (NTRS)

    Rood, Richard B.; Stajner, Ivanka; Phelps, Carrie; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The Data Assimilation Office at NASA's Goddard Space Flight Center provides global 3D ozone fields at six-hour time intervals. Data from Total Ozone Mapping Spectrometer (TOMS) and the Solar Backscatter Ultraviolet (SBUV) instrument are used in the assimilation. TOMS provides total column information and SBUV provides profile information, primarily above the ozone peak. Information below the ozone peak comes from the model. This paper will explore the realism of the assimilated ozone in the upper troposphere and lower stratosphere through validation with ozonesondes, Halogen Occultation Experiment (HALOE), and Polar Ozone and Aerosol Measurement (POAM) observations. This work is in preparation of using the assimilated ozone in the radiative calculation for the meteorological assimilation as well as in the derivation of tropospheric ozone.

  7. Multi-Model Assessment of the Factors Driving Stratospheric Ozone Evolution Over the 21st Century

    NASA Technical Reports Server (NTRS)

    Oman, L. D.; Plummer, D. A.; Waugh, D. W.; Austin, J.; Scinocca, J.; Douglass, A. R.; Salawitch, R. J.; Canty, T.; Akiyoshi, H.; Bekki, S.; Braesicke, P.; Butchart, N.; Chipperfield, M. P.; Cugnet, D.; Dhomse, S.; Eyring, V.; Frith, S.; Hardiman, S. C.; Kinnison, D. E.; Lamarque, J. F.; Mancini, E.; Marchand, M.; Michou, M.; Morgenstern, O.; Nakamura T.

    2010-01-01

    The evolution of stratospheric ozone from 1960 to 2100 is examined in simulations from fourteen chemistry-climate models. There is general agreement among the models at the broadest levels, showing column ozone decreasing at all latitudes from 1960 to around 2000, then increasing at all latitudes over the first half of the 21st century, and latitudinal variations in the rate of increase and date of return to historical values. In the second half of the century, ozone is projected to continue increasing, level off or even decrease depending on the latitude, resulting in variable dates of return to historical values at latitudes where column ozone has declined below those levels. Separation into partial column above and below 20 hPa reveals that these latitudinal differences are almost completely due to differences in the lower stratosphere. At all latitudes, upper stratospheric ozone increases throughout the 21st century and returns to 1960 levels before the end of the century, although there is a spread among the models in dates that ozone returns to historical values. Using multiple linear regression, we find decreasing halogens and increasing greenhouse gases contribute almost equally to increases in the upper stratospheric ozone. In the tropical lower stratosphere an increase in tropical upwelling causes a steady decrease in ozone through the 21st century, and total column ozone does not return to 1960 levels in all models. In contrast, lower stratospheric and total column ozone in middle and high latitudes increases during the 21st century and returns to 1960 levels.

  8. Mechanisms and Feedbacks Causing Changes in Upper Stratospheric Ozone in the 21st Century

    NASA Technical Reports Server (NTRS)

    Oman, Luke; Waugh, D. W.; Kawa, S. R.; Stolarski, R. S.; Douglass, A. R.; Newman, P. A.

    2009-01-01

    Stratospheric ozone is expected to increase during the 21st century as the abundance of halogenated ozone-depleting substances decrease to 1960 values. However, climate change will likely alter this "recovery" of stratospheric ozone by changing stratospheric temperatures, circulation, and abundance of reactive chemical species. Here we quantity the contribution of different mechanisms to changes in upper stratospheric ozone from 1960 to 2100 in the Goddard Earth Observing System Chemistry-Climate Model (GEOS CCM), using multiple linear regression analysis applied to simulations using either Alb or A2 greenhouse gas (GHG) scenarios. In both these scenarios upper stratospheric ozone has a secular increase over the 21st century. For the simulation using the Alb GHG scenario, this increase is determined by the decrease in halogen amounts and the greenhouse gas induced cooling, with roughly equal contributions from each mechanism. There is a larger cooling in the simulation using the A2 GHG scenario, but also enhanced loss from higher NOy and HOx concentrations, which nearly offsets the increase due to cooler temperatures. The resulting ozone evolutions are similar in the A2 and Alb simulations. The response of ozone due to feedbacks from temperature and HOx changes, related to changing halogen concentrations, are also quantified using simulations with fixed halogen concentrations.

  9. Numerical simulation of global variations of temperature, ozone, and trace species in the stratosphere

    SciTech Connect

    Smith, A.K.

    1995-01-01

    A three-dimensional dynamical chemical model of the middle atmosphere is used to examine the global response to planetary waves in the middle and high latitudes of the northern hemisphere. The model indicates that larger wave activity in the lower stratosphere at 60 deg N is correlated with decreasing zonal mean temperatures throughout the tropical and summer hemisphere stratosphere as a result of an induced global-scale circulation. The tendency of mean ozone is positively correlated with the temperature tendency in the lower stratosphere and negatively correlated in the upper stratosphere. In the upper stratosphere, the anticorrelation of mean ozone and temperature is due primarily to the temperature dependence of many of the reaction rates. The quantitative agreement of the model results with available observations is better when the dependence of the ozone-temperature relation on the mean zone amount is removed (by taking the log of ozone) because the model ozone differs from the observed. A model run in which the atmospheric chlorine is removed indicates that the magnitude of the ozone change for a given temperature change can be substantial for modifications in the model photochemistry. Another run tested a more realistic change in which a key reaction rate is modified; the results indicate differences of greater than 10% in the ratio of ozone to temperature changes. With improved measurement capabilities differences of this order may now or soon be detectable. The variations of other chemical species in the model with temperature are also presented.

  10. The dynamics of the stratospheric polar vortex and its relation to springtime ozone depletions.

    PubMed

    Schoeberl, M R; Hartmann, D L

    1991-01-01

    Dramatic springtime depletions of ozone in polar regions require that polar stratospheric air has a high degree of dynamical isolation and extremely cold temperatures necessary for the formation of polar stratospheric clouds. Both of these conditions are produced within the stratospheric winter polar vortex. Recent aircraft missions have provided new information about the structure of polar vortices during winter and their relation to polar ozone depletions. The aircraft data show that gradients of potential vorticity and the concentration of conservative trace species are large at the transition from mid-latitude to polar air. The presence of such sharp gradients at the boundary of polar air implies that the inward mixing of heat and constituents is strongly inhibited and that the perturbed polar stratospheric chemistry associated with the ozone hole is isolated from the rest of the stratosphere until the vortex breaks up in late spring. The overall size of the polar vortex thus limits the maximum areal coverage of the annual polar ozone depletions. Because it appears that this limit has not been reached for the Antarctic depletions, the possibility of future increases in the size of the Antarctic ozone hole is left open. In the Northern Hemisphere, the smaller vortex and the more restricted region of cold temperatures suggest that this region has a smaller theoretical maximum for column ozone depletion, about 40 percent of the currently observed change in the Antarctic ozone column in spring.

  11. Dynamics of the stratospheric polar vortex and its relation to springtime ozone depletions

    SciTech Connect

    Schoeberl, M.R. ); Hartmann, D.L. )

    1991-01-01

    Dramatic springtime depletions of ozone in polar regions require that polar stratospheric air has a high degree of dynamical isolation and extremely cold temperatures necessary for the formation of polar stratospheric clouds. Both of these conditions are produced within the stratospheric winter polar vortex. Recent aircraft missions have provided new information about the structure of polar vortices during winter and their relation to polar ozone depletions. The aircraft data show that gradients of potential vorticity and the concentration of conservative trace species are large at the transition from mid-latitude to polar air. The presence of such sharp gradients at the boundary of polar air implies that the inward mixing of heat and constituents is strongly inhibited and that the perturbed polar stratospheric chemistry associated with the ozone hole is isolated from the rest of the stratosphere until the vortex breaks up in late spring. The overall size of the polar vortex thus limits the maximum areal coverage of the annual polar ozone depletions. Because it appears that this limit has not been reached for the Antarctic depletions, the possibility of future increases in the size of the Antarctic ozone hole is left open. In the Northern Hemisphere, the smaller vortex and the more restricted region of cold temperatures suggest that this region has a smaller theoretical maximum for column ozone depletion, about 40 percent of the currently observed change in the Antarctic ozone column in spring. 5 figs., 43 refs.

  12. Mechanisms and feedback causing changes in upper stratospheric ozone in the 21st century

    NASA Astrophysics Data System (ADS)

    Oman, L. D.; Waugh, D. W.; Kawa, S. R.; Stolarski, R. S.; Douglass, A. R.; Newman, P. A.

    2010-03-01

    Stratospheric ozone is expected to increase during the 21st century as the abundance of halogenated ozone-depleting substances decrease to 1960 values. However, climate change will likely alter this "recovery" of stratospheric ozone by changing stratospheric temperatures, circulation, and abundance of reactive chemical species. Here we quantify the contribution of different mechanisms to changes in upper stratospheric ozone from 1960 to 2100 in the Goddard Earth Observing System chemistry-climate model, using multiple linear regression analysis applied to simulations using either A1b or A2 greenhouse gas (GHG) scenarios. In both scenarios, upper stratospheric ozone has a secular increase over the 21st century. For the simulation using the A1b GHG scenario, this increase is determined by the decrease in halogen amounts and the GHG-induced cooling, with roughly equal contributions from each mechanism. There is a larger cooling in the simulation using the A2 GHG scenario, but also enhanced loss from higher NOy and HOx concentrations, which nearly offsets the increase because of cooler temperatures. The resulting ozone evolutions are similar in the A2 and A1b simulations. The response of ozone caused by feedback from temperature and HOx changes, related to changing halogen concentrations, is also quantified using simulations with fixed-halogen concentrations.

  13. Interhemispheric Differences in Dentifrication and Related Processes Affecting Polar Ozone

    NASA Technical Reports Server (NTRS)

    Santee, M. L.; Read, W. G.; Waters, J. W.; Froidevaux, L.; Manney, G. L.; Flower, D. A.; Jarnot, R. F.; Harwood, R. S.; Peckham, G. E.

    1994-01-01

    The severe depletion of stratospheric ozone over Antarctica in late winter and early spring is caused by enhanced CLO abundances arising from heterogeneous reactions on polar stratospheric clouds (PSCs). CLO abundances comparable to those over Antarctica have also been observed throughout the Arctic Vortex, but the accompanying loss of Arctic ozone has been much less severe.

  14. Chlorine catalyzed destruction of ozone - Implications for ozone variability in the upper stratosphere

    NASA Technical Reports Server (NTRS)

    Chandra, Sushil; Jackman, Charles H.; Douglass, Anne R.; Fleming, Eric L.; Considine, David B.

    1993-01-01

    The annual mean and the annual amplitude of ozone have been derived from ozone measurements from the SBUV and SBUV/2 spectrometers on board the Nimbus-7 and NOAA-11 satellites. These values differ significantly from values calculated using a two-dimensional model of stratospheric photochemistry and dynamics with standard chemistry. We have found that the differences between the calculated and data-derived values are considerably improved by changing the partitioning in the Cly family to create a larger reservoir of HCl and reducing ClO. This is accomplished by including a channel for the products HCl + O2 from the reaction ClO + OH in addition to the products Cl + HO2. This partitioning also improves the agreement between the calculated and measured values of ClO/HCl ratio.

  15. Ozone and nitrogen dioxide changes in the stratosphere during 1979-84

    NASA Technical Reports Server (NTRS)

    Callis, Linwood B.; Natarajan, Murali

    1986-01-01

    Analyses of stratospheric nitrogen dioxide distributions as measured by four different satellite experiments indicate midlatitude increases of up to 75 percent during the 1979-84 period. These increases are attributed to enhanced upper atmospheric formation of odd nitrogen during solar cycle 21 with downward transport to the stratosphere. The increases in NO2 provide an explanation for the recently observed dramatic springtime minima in the Antarctic ozone and suggest the reason for the reported midlatitude stratospheric ozone decreases observed by satellite and ground-based stations since the mid 1970s.

  16. Intercomparison of stratospheric ozone and temperature profiles during the October 2005 Hohenpeissenberg Ozone Profiling Experiment (HOPE)

    NASA Astrophysics Data System (ADS)

    Steinbrecht, W.; McGee, T. J.; Twigg, L. W.; Claude, H.; Schönenborn, F.; Sumnicht, G. K.; Silbert, D.

    2009-01-01

    Thirteen clear nights in October 2005 allowed successful intercomparison of the stationary lidar operated since 1987 by the German Weather Service (DWD) at Hohenpeissenberg (47.8° N, 11.0° E) with the Network for the Detection of Atmospheric Composition Change (NDACC) travelling standard lidar operated by NASA's Goddard Space Flight Center. Both lidars provide ozone profiles in the stratosphere, and temperature profiles in the strato- and mesosphere. Additional ozone profiles came from on-site Brewer/Mast ozonesondes, additional temperature profiles from Vaisala RS92 radiosondes launched at Munich (65 km north-east), and from operational analyses by the US National Centers for Environmental Prediction (NCEP). The intercomparison confirmed a low bias for ozone from the DWD lidar in the 33 to 43 km region, by up to 10%. This bias is caused by the DWD ozone algorithm. It will be removed in a future version. Between 20 and 33 km, agreement between both lidars, and ozonesondes below 30 km, is good with ozone differences less than 3 to 5%. Results are consistent with previous comparisons of the DWD lidar with SAGE, GOMOS and other satellite instruments. The intercomparison did uncover a 290 m upward shift of the DWD lidar data. When this shift is removed, agreement with ozone from the NASA lidar improves below 20 km, with remaining differences usually less than 5%, and not statistically significant. Precision (repeatability) for the lidar ozone data is better than 5% between 20 and 40 km altitude, dropping to 10% near 45 km, and 50% near 50 km. Temperature from the DWD lidar has a 1 to 2 K cold bias from 30 to 65 km against the NASA lidar, and a 2 to 4 K cold bias against radiosondes and NCEP. This is consistent with previous intercomparisons against NCEP or radiosondes. The cold bias against the NASA lidar disappears when the DWD lidar data are corrected for the afore-mentioned 290 m range error, and more appropriate values for the Earth's gravity acceleration are

  17. As estimation of the climatic effects of stratospheric ozone losses during the 1980s

    SciTech Connect

    MacKay, R.M.; Ko, M.K.W.; Yang, Yajaing

    1997-04-01

    In order to study the potential climatic effects of the ozone hole more directly and to assess the validity of previous lower resolution model results, the latest high spatial resolution version of the Atmospheric and Environmental Research, Inc., seasonal radiative dynamical climate model is used to simulate the climatic effects of ozone changes relative to the other greenhouse gases. The steady-state climatic effect of a sustained decrease in lower stratospheric ozone, similar in magnitude to the observed 1979-90 decrease, is estimated by comparing three steady-state climate simulations: (I) 1979 greenhouse gas concentrations and 1979 ozone, (II) 1990 greenhouse gas concentrations with 1979 ozone, and (III) 1990 greenhouse gas concentrations with 1990 ozone. The simulated increase in surface air temperature resulting from nonozone greenhouse gases is 0.272 K. When changes in lower stratospheric ozone are included, the greenhouse warming is 0.165 K, which is approximately 39% lower than when ozone is fixed at the 1979 concentrations. Ozone perturbations at high latitudes result in a cooling of the surface-troposphere system that is greater (by a factor of 2.8) than that estimated from the change in radiative forcing resulting from ozone depletion and the model`s 2 X CO{sub 2} climate sensitivity. The results suggest that changes in meridional heat transport from low to high latitudes combined with the decrease in the infrared opacity of the lower stratosphere are very important in determining the steady-state response to high latitude ozone losses. The 39% compensation in greenhouse warming resulting from lower stratospheric ozone losses is also larger than the 28% compensation simulated previously by the lower resolution model. The higher resolution model is able to resolve the high latitude features of the assumed ozone perturbation, which are important in determining the overall climate sensitivity to these perturbations. 39 refs., 11 figs., 4 tabs.

  18. An Estimation of the Climatic Effects of Stratospheric Ozone Losses during the 1980s. Appendix K

    NASA Technical Reports Server (NTRS)

    MacKay, Robert M.; Ko, Malcolm K. W.; Shia, Run-Lie; Yang, Yajaing; Zhou, Shuntai; Molnar, Gyula

    1997-01-01

    In order to study the potential climatic effects of the ozone hole more directly and to assess the validity of previous lower resolution model results, the latest high spatial resolution version of the Atmospheric and Environmental Research, Inc., seasonal radiative dynamical climate model is used to simulate the climatic effects of ozone changes relative to the other greenhouse gases. The steady-state climatic effect of a sustained decrease in lower stratospheric ozone, similar in magnitude to the observed 1979-90 decrease, is estimated by comparing three steady-state climate simulations: 1) 1979 greenhouse gas concentrations and 1979 ozone, II) 1990 greenhouse gas concentrations with 1979 ozone, and III) 1990 greenhouse gas concentrations with 1990 ozone. The simulated increase in surface air temperature resulting from nonozone greenhouse gases is 0.272 K. When changes in lower stratospheric ozone are included, the greenhouse warming is 0.165 K, which is approximately 39% lower than when ozone is fixed at the 1979 concentrations. Ozone perturbations at high latitudes result in a cooling of the surface-troposphere system that is greater (by a factor of 2.8) than that estimated from the change in radiative forcing resulting from ozone depiction and the model's 2 x CO, climate sensitivity. The results suggest that changes in meridional heat transport from low to high latitudes combined with the decrease in the infrared opacity of the lower stratosphere are very important in determining the steady-state response to high latitude ozone losses. The 39% compensation in greenhouse warming resulting from lower stratospheric ozone losses is also larger than the 28% compensation simulated previously by the lower resolution model. The higher resolution model is able to resolve the high latitude features of the assumed ozone perturbation, which are important in determining the overall climate sensitivity to these perturbations.

  19. 76 FR 44001 - Protection of Stratospheric Ozone: Request for Applications for Essential Use Allowances for 2013...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-22

    ... that Deplete the Ozone Layer. The U.S. Government will use the applications received in response to... AGENCY Protection of Stratospheric Ozone: Request for Applications for Essential Use Allowances for 2013.... Essential use allowances provide exemptions from the phaseout of production and import of...

  20. 75 FR 25780 - Protection of Stratospheric Ozone: Allocation of Essential Use Allowances for Calendar Year 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-10

    ....S. Government and by the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer... AGENCY 40 CFR Part 82 RIN-2060-AP59 Protection of Stratospheric Ozone: Allocation of Essential Use...: With this action, EPA is allocating essential use allowances for import and production of Class I...

  1. 75 FR 42747 - Protection of Stratospheric Ozone: Request for Applications for Essential Use Allowances for 2012...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-22

    ... that Deplete the Ozone Layer. The U.S. Government will use the applications received in response to... AGENCY Protection of Stratospheric Ozone: Request for Applications for Essential Use Allowances for 2012.... Essential use allowances provide exemptions from the phaseout of production and import of...

  2. In-situ measurements of tropospheric and stratospheric ozone over Hyderabad

    NASA Astrophysics Data System (ADS)

    Manchanda, R. K.; Sreenivasan, S.; Sinha, P. R.

    The Study of the ozone concentration and its variability is one of the key indexes for environmental and ecological degradation While the stratospheric ozone absorbs the harmful ultraviolet radiation between 280-320 nm band, the tropospheric ozone is formed in the elevated layers up to 10km above ground level through the photochemical decomposition of the precursor gases like NOx, VOCs and non-methane hydrocarbons (NMHCs) released from the earth surface. Ozone studies are also vital for the understanding of solar terrestrial coupling as well as the ozone chemistry on a given site and its surroundings. Continuous measurements of vertical profile of ozone and various meteorological parameters (i.e. temperature, pressure, humidity, wind speed and direction) over one year period were made over Hyderabad using high altitude plastic balloons, in order to investigate i. variations of ozone in the troposphere and stratosphere, ii. stratospheric warming iii. coupling between upper troposphere and lower stratosphere (UTLS) region. Ozonesonde (Electro Chemical Cell) coupled with GPS RS80-15N radiosonde was used for the measurement of Ozone and meteorological parameters.

  3. Trends in Stratospheric Ozone Derived from Merged Odin-OSIRIS and SAGE II Satellite Observations

    NASA Astrophysics Data System (ADS)

    Roth, C.; Degenstein, D. A.; Bourassa, A. E.

    2014-12-01

    Stratospheric ozone profile measurements from the Optical Spectrograph and InfraRed Imager System (OSIRIS) instrument on the Odin satellite (2001-Present) are merged with those from the Stratospheric Aerosol and Gas Experiment (SAGE) II satellite instrument (1984-2005) to calculate decadal trends in stratospheric ozone between 60°S and 60°N. A multi-instrument, multi-decade, deseasonalized and merged stratospheric ozone record (1984-present) is produced by analyzing the measurements during the operational overlap of both satellites (2001-2005). The deseasonalized monthly time series is fit using linear regression with six non-linear predictor basis functions: three quasi-biennial oscillation proxies, the El Niño- Southern Oscillation index, a solar activity proxy, and the NCEP pressure at the tropical tropopause; and two linear trends: before and after 1997, which give the decadal trends in ozone. From 1984-1997, statistically significant negative trends of 5-10% per decade exist throughout the stratosphere (30-50 km). From 1997-present, statistically significant recovery rates of 3-8% per decade exist throughout most of the stratosphere. Below 22 km and between 40°S-40°N a negative trend is measured before and after 1997. The recovery is not significant in the tropical stratosphere between 25-35 km.

  4. Study of the lower stratospheric thermal structure and total ozone from Nimbus-4 IRIS

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.

    1976-01-01

    The global distribution of temperature in the stratosphere from 100 to 10 mbar and the total ozone in the atmosphere are remotely sensed from the Nimbus-4 IRIS measurements for a period of about one year. The temperature and ozone data are presented in the form of monthly mean global maps. The standard deviations of temperature and ozone with respect to zonal averages are calculated. The mean and the variable state of the stratosphere are discussed with the help of these observations. The lower stratosphere in the tropical regions reveals a significant wave number one pattern in the circulation. The Arctic and Antarctic stratospheric winter circulation regimes display a different behavior apparently due to the ocean and orographic differences.

  5. Fluctuations of total ozone and their relationship to stratospheric air motions

    NASA Technical Reports Server (NTRS)

    Salby, Murry L.; Callaghan, Patrick F.

    1993-01-01

    The origin of fluctuations of total ozone and the interactions that take place between the distribution of total ozone and the circulation of the troposphere are investigated on the basis of observations of total ozone from Nimbus 7 TOMS together with contemporaneous analyses of the circulation. It is shown that a sizable component of total ozone variability is explained by the quasi-columnar motion of air in the lower stratosphere. The development also suggests that in combination with isentropic analyses, total ozone measurements can provide a detailed picture of air motions in the lower stratosphere. Distributions of ozone column abundance and pressure on the 375-K isentropic surface for the Northern and Southern Hemispheres are illustrated.

  6. An investigation into the causes of stratospheric ozone loss in the southern Australasian region

    NASA Technical Reports Server (NTRS)

    Lehmann, P.; Karoly, D. J.; Newmann, P. A.; Clarkson, T. S.; Matthews, W. A.

    1992-01-01

    Measurements of total ozone at Macquarie Island (55 deg S, 159 deg E) reveal statistically significant reductions of approximately twelve percent during July to September when comparing the mean levels for 1987-90 with those in the seventies. In order to investigate the possibility that these ozone changes may not be a result of dynamic variability of the stratosphere, a simple linear model of ozone was created from statistical analysis of tropopause height and isentropic transient eddy heat flux, which were assumed representative of the dominant dynamic influences. Comparison of measured and modeled ozone indicates that the recent downward trend in ozone at Macquarie Island is not related to stratospheric dynamic variability and therefore suggests another mechanism, possibly changes in photochemical destruction of ozone.

  7. Natural variability of tropical upper stratospheric ozone inferred from the Atmosphere Explorer backscatter ultraviolet experiment

    NASA Technical Reports Server (NTRS)

    Frederick, J. E.; Abrams, R. B.; Dasgupta, R.; Guenther, B.

    1981-01-01

    Analysis of backscattered ultraviolet radiances observed at tropical latitudes by the Atmosphere Explorer-E satellite reveals both annual and semiannual cycles in upper stratospheric ozone. The annual variation dominates the signal at wavelengths which sense ozone primarily above 45 km while below this, to the lowest altitude sensed, 35 km, the semiannual component has comparable amplitude. Comparison of radiance measurements taken with the same instrument at solar minimum during 1976 and solar maximum in 1979 show no significant differences. This suggests that variations in upper stratospheric ozone over the solar cycle are small, although the data presently available do not allow a definite conclusion.

  8. 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.

  9. Measurement intercomparison of the JPL and GSFC stratospheric ozone lidar systems

    NASA Technical Reports Server (NTRS)

    Mcdermid, I. Stuart; Walsh, T. Daniel; Godin, Sophie M.; Lindqvist, L. Oscar; Burris, John; Ferrare, Richard; Whiteman, David; Mcgee, Thomas J.; Butler, James

    1990-01-01

    For approximately one month during October and November 1988 the NASA Goddard Space Flight Center mobile lidar system was brought to the Jet Propulsion Laboratory, Table Mountain Facility, to make side-by-side measurements with the JPL lidar of stratospheric ozone concentration profiles. Measurements were made by both excimer laser DIAL systems on fifteen nights during this period. The results showed good agreement of the ozone profiles measured between 20- and 40-km altitude. This is believed to be the first reported side-by-side measurement intercomparison of two stratospheric ozone lidar systems.

  10. Stratospheric ozone isotope enrichment studied by submillimeter-wave heterodyne radiometry

    NASA Astrophysics Data System (ADS)

    Kasai, Y.; Urban, J.; Takahashi, K.; JEM/SMILES Science-Team,

    2002-05-01

    Since the discovery of the heavy isotope enrichment of ozone formation in the stratosphere in 1981, considerable progress has been made in understanding the processes that control the isotope enrichment by using mass spectrometry, spectrometric techniques, laboratory measurements, and so on. The detection limit of the mass spectrometers is enough to discuss these isotope enrichments, but symmetric and asymmetric ozone isotopes cannot be distinguished. It is important to observe symmetric and asymmetric ozone isotopes separately with enough accuracy to understand the mechanism of the ozone isotope enrichment for the ozone formation chemistry. Measurements of the ozone isotopes using a new technology of he superconducting submillimeter-wave limb emission spectrometer (SMILES) have been proposed. The instrument is planned to be aboard the Japanese Experiment Module (JEM) at the International Space Station. The SMILES instrument is planned to be launched in 2006. The SMILES instrument measures thermal emissions from ozone isotopes as well as ozone-depletion-related molecules such as ClO, HCl, HO2, HNO3 and BrO in the frequency bands at 624.32-626.32 GHz and 649.12-650.32 GHz. Overview of this experiment, such as new techniques for a high-sensitive sounding, measurement coverage, measurement frequency, is described. The scientific objective of the SMILES experiment, including a brief review on the controversial problem of stratospheric ozone isotope anomaly, is presented. The error analysis of the SMILES measurement is evaluated by using the SMILES simulator for all 5 isotopes of normal ozone, asymmetric-17-ozone, asymmetric-18-ozone, symmetric-17-ozone, symmetric-18-ozone. The evaluation suggests that the global distributions of symmetric-17-ozone, asymmetric-18-ozone, symmetric-17-ozone, as well as normal ozone can be obtained from the single profile, with the errors of less than about 1 % between 20 and 40 km with the partial column about 5 km.

  11. Ozone in the stratosphere. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    Not Available

    1994-03-01

    The bibliography contains citations concerning empirical and theoretical studies and analyses of stratospheric ozone. The processing of upper atmospheric ozone concentrations that vary with ozone transport, formation, and depletion, and data collection using ground-based, airborne and satellite-borne instrumentation and sensors are examined. Citations cover studies on atmospheric composition, reaction kinetics, particle physics, chemical reactions, photochemistry, and atmospheric models of ozone. Investigations are based on the photochemistry, ozone constituents, and long-term measurement data. References to the Antarctic October depletion phenomenon are included. (Contains 250 citations and includes a subject term index and title list.)

  12. Ozone in the stratosphere. (Latest citations from the NTIS Bibliographic database). Published Search

    SciTech Connect

    Not Available

    1993-09-01

    The bibliography contains citations concerning empirical and theoretical studies and analyses of stratospheric ozone. The processing of upper atmospheric ozone concentrations that vary with ozone transport, formation, and depletion, and data collection using ground-based, airborne and satellite-borne instrumentation and sensors are examined. Citations cover studies on atmospheric composition, reaction kinetics, particle physics, chemical reactions, photochemistry, and atmospheric models of ozone. Investigations are based on the photochemistry, ozone constituents, and long-term measurement data. References to the Antarctic October depletion phenomenon are included. (Contains 250 citations and includes a subject term index and title list.)

  13. Changes in the Ozone Content over Central Europe During Reversals of Stratospheric Circulation in Late Winter

    NASA Technical Reports Server (NTRS)

    Entzian, G.; Grasnick, K. H.

    1984-01-01

    A superposed epoch analysis during late winter zonal wind reversals was carried out from 18 year observation series (1963 to 1980) of the meridional geopotential height gradient in the 30 mb level (latitude mean) and of the ozone content over central Europe. Experimental data suggest that if planetary waves are responsible for the additional meridional ozone transport during stratospheric warmings, this transport has to take place at heights other than those up to the ozone maximum in the middle latitudes.

  14. Characteristics of polar stratospheric clouds during the formation of the Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Hamill, Patrick; Toon, O. B.; Turco, R. P.

    1986-01-01

    Measured properties of Antarctic polar stratospheric clouds are described, and the possible relationship between the clouds and the formation of the ozone hole is considered. It is shown that the ozone hole develops and the clouds dissipate in the same place and at the same time. There may be a causal relationship between cloud particle evaporation and ozone depletion. A heterogeneous mechanism involving chemical reactions in the cloud droplets is suggested.

  15. A global climatology of tropospheric and stratospheric ozone derived from Aura OMI and MLS measurements

    NASA Astrophysics Data System (ADS)

    Ziemke, J. R.; Chandra, S.; Labow, G.; Bhartia, P. K.; Froidevaux, L.; Witte, J. C.

    2011-06-01

    A global climatology of tropospheric and stratospheric column ozone is derived by combining six years of Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone measurements for the period October 2004 through December 2010. The OMI/MLS tropospheric ozone climatology exhibits large temporal and spatial variability which includes ozone accumulation zones in the tropical south Atlantic year-round and in the subtropical Mediterranean/Asia region in summer months. High levels of tropospheric ozone in the Northern Hemisphere also persist in mid-latitudes over the Eastern North American and Asian continents extending eastward over the Pacific Ocean. For stratospheric ozone climatology from MLS, largest ozone abundance lies in the Northern Hemisphere in the latitude range 70° N-80° N in February-April and in the Southern Hemisphere around 40° S-50° S during months August-October. The largest stratospheric ozone abundances in the Northern Hemisphere lie over North America and Eastern Asia extending eastward across the Pacific Ocean and in the Southern Hemisphere south of Australia extending eastward across the dateline. With the advent of many newly developing 3-D chemistry and transport models it is advantageous to have such a dataset for evaluating the performance of the models in relation to dynamical and photochemical processes controlling the ozone distributions in the troposphere and stratosphere. The OMI/MLS ozone gridded climatology data, both calculated mean values and RMS uncertainties are made available to the science community via the NASA total ozone mapping spectrometer (TOMS) website http://toms.gsfc.nasa.gov.

  16. Stratospheric ozone with added water vapor: influence of high-altitude aircraft.

    PubMed

    Harrison, H

    1970-11-13

    Simple, steady-state models for ozone photochemistry, radiative heat balance, and eddy-diffusive mass transport can be combined to estimate water-induced changes in the stratospheric ozone concentrations and temperatures, the integrated ozone column, the solar power transmitted to the earth's surface, and the surface temperature. These changes have been computed parametrically for mixing fractions of water vapor between 3 x 10(-6) and 6.5 x 10(-6). With added water from the exhausts of projected fleets of stratospheric aircraft, the ozone column may diminish by 3.8 percent, the transmitted solar power increase by 0.07 percent, and the surface temperature rise by 0.04 degrees K in the Northern Hemisphere. Due to a cancellation of terms, temperatures in the lower stratosphere remain essentially unchanged. These results are sensitive to the form of the water profile and emphasize the potential role of convective transients near 30 kilometers.

  17. Relationship between stratospheric tracers and surface ozone at a mid-latitude site

    NASA Astrophysics Data System (ADS)

    Lefer, B. L.; Seda, E.; Morris, G. A.; Talbot, R. W.; Dibb, J. E.

    2012-12-01

    Stratospheric ozone influences the composition of the free troposphere through Stratosphere-Troposphere Exchange (STE). Tropopause folds are a fairly common STE phenomena in extratropical regions contribute that potentially contribute to surface ozone. However, the magnitude of STE contribution to surface ozone is poorly quantified. In the Spring of 2012 7Be , ozonesonde and relative humidty profiles, and speciated Hg measurements, were used to identify stratospherically impacted air masses. Several frontal passages were analyzed using both the SUNY-Albany Global Forecast System (GFS) model of potential vorticity and tropopause height and the NOAA Air Resources Laboratory (ARL) Hysplit trajectory model. This analysis will be used estimate the amount of ozone brought down to the surface in Houston Texas through springtime STE events.

  18. Identification of Stratospheric Waves in Ozone in the Tropics from OMI High Spectral Resolution Measurements

    NASA Technical Reports Server (NTRS)

    Ziemke, J. R.; Liu, X.; Bhartia, P. K.

    2007-01-01

    Previous studies using Total Ozone Mapping Spectrometer (TOMS) measurements have identified several types of tropical waves in the stratosphere. These waves include Kelvin waves, mixed Rossby-gravity waves, equatorial Rossby waves, and global normal modes. All of these detected waves occur when their zonal phase speeds are opposite the zonal winds in the low-mid stratosphere associated with the Quasi-biennial Oscillation (QBO). Peak-to-peak amplitudes in all cases are typically 5 DU. While total ozone data from TOMS is sensitive in detecting these tropical waves, they provide each day only a single horizontal cross-sectional map. The high spatial and spectral resolution of the Aura Ozone Monitoring Instrument (OMI) provides a unique means to evaluate 3D structure in these waves including their propagation characteristics. Ozone profiles retrieved from OMI radiances for wavelengths 270-310 nm are utilized to examine the nature of these wave disturbances extending from the lower to upper stratosphere.

  19. New Differential Absorption Lidar for Stratospheric Ozone Monitoring in Argentina

    NASA Astrophysics Data System (ADS)

    Wolfram, Elian A.; Salvador, Jacobo; D'Elia, Raul; Pazmiño, Andrea; Godin-Beeckmann, Sophie; Nakane, Hideki; Quel, Eduardo

    2008-04-01

    As part of environmental studies concerning with measurements of the stratospheric ozone layer, the CEILAP developed a new Differential Absorption Lidar (DIAL) instrument. Since the early construction of the first DIAL instrument, Lidar Division has been made important financial and scientific investments to improve this initial prototype. The new version has a bigger reception system formed by 4 newtonian telescopes of 50 cm diameter each one and a higher number of detection channels: four different wavelengths are detected simultaneously and six digital channels record the Rayleigh and Raman backscattered photons emitted by an ClXe Excimer laser at 308 nm and third harmonic of Nd-YAG laser at 355 nm. A number of different changes have been made to increase the dynamical range of this lidar: a mechanical chopper was installed together with gated photomultiplier in the high energy detection channels to avoid strong signals from lower atmospheric layers. This new version was installed inside a shelter given the possibility to make field campaigns outside CEILAP laboratories as SOLAR Campaign made in Argentine Patagonian region during 2005-2006 springs. In this paper a full description of instrument update is given. Intercomparisons with ozonesonde and satellite platform instrument are presented. The results show agreement better than 10% in 16-38 km range when same airmasses are sampled.

  20. Influence of isentropic transport on seasonal ozone variations in the lower stratosphere and subtropical upper troposphere

    NASA Technical Reports Server (NTRS)

    Jing, P.; Cunnold, D. M.; Yang, E.-S.; Wang, H.-J.

    2005-01-01

    The isentropic cross-tropopause ozone transport has been estimated in both hemispheres in 1999 based on the potential vorticity mapping of Stratospheric Aerosol and Gas Experiment 11 ozone measurements and contour advection calculations using the NASA Goddard Space Flight Center Global and Modeling Assimilation Office analysis. The estimated net isentropic stratosphere-to-troposphere ozone flux is approx.118 +/- 61 x 10(exp9)kg/yr globally within the layer between 330 and 370 K in 1999; 60% of it is found in the Northern Hemisphere, and 40% is found in the Southern Hemisphere. The monthly average ozone fluxes are strongest in summer and weakest in winter in both hemispheres. The seasonal variations of ozone in the lower stratosphere (LS) and upper troposphere (UT) have been analyzed using ozonesonde observations from ozonesonde stations in the extratropics and subtropics, respectively. It is shown that observed ozone levels increase in the UT over subtropical ozonesonde stations and decrease in the LS over extratropical stations in late spring/early summer and that the ozone increases in the summertime subtropical UT are unlikely to be explained by photochemical ozone production and diabatic transport alone. We conclude that isentropic transport is a significant contributor to ozone levels in the subtropical upper troposphere, especially in summer.

  1. Inter-Annual and Decadal Changes in Tropospheric and Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Ziemke, Jr. R.; Chandra, S.

    2011-01-01

    Ozone data beginning October 2004 from the Aura Ozone Monitoring Instrument (OMI) and Aura Microwave Limb Sounder (MLS) are used to evaluate the accuracy of the Cloud slicing technique in effort to develop long data records of tropospheric and stratospheric ozone and studying their long-term changes. Using this technique, we have produced a 32-year (1979-2010) long record of tropospheric and stratospheric ozone from the combined Total Ozone Mapping Spectrometer (Toms) and OMI. The analyses of these time series suggest that the quasi-biennial oscillation (QBO) is the dominant source of inter-annual changes of 30-40 Dobson Units (DU). Tropospheric ozone also indicates a QBO signal in the peak to peak changes varying from 2 to 7 DU. Decadal changes in global stratospheric ozone indicate a turnaround in ozone loss around mid 1990's with most of these changes occurring in the Northern Hemisphere from the subtropics to high latitudes. The trend results are generally consistent with the prediction of chemistry climate models which include the reduction of ozone destroying substances beginning in the late 1980's mandated by the Montreal Protocol.

  2. Stratospheric contribution to surface ozone in the desert Southwest during the 2013 Las Vegas Ozone Study

    NASA Astrophysics Data System (ADS)

    Langford, A. O.; Senff, C. J.; Alvarez, R. J. _II, II; Brioude, J. F.; Cooper, O. R.; Holloway, J. S.; Lin, M.; Marchbanks, R.; Pierce, R. B.; Reddy, P. J.; Sandberg, S.; Weickmann, A. M.; Williams, E. J.; Gustin, M. S.; Iraci, L. T.; Leblanc, T.; Yates, E. L.

    2014-12-01

    The 2013 Las Vegas Ozone Study (LVOS) was designed to investigate the potential impact of stratosphere-troposphere transport (STT) and long-range transport of pollution from Asia on surface O3 concentrations in Clark County, NV. This measurement campaign, which took place in May and June of 2013, was conducted at Angel Peak, NV, a high elevation site about 2.8 km above mean sea level and 45 km west of Las Vegas. The study was organized around the NOAA ESRL truck-based TOPAZ scanning ozone lidar with collocated in situ sampling of O3, CO, and meteorological parameters. These measurements were supported by the NOAA/NESDIS real time modelling system (RAQMS), FLEXPART particle dispersion model, and the NOAA GFDL AM3 model. In this talk, I will describe one of several STT events that occurred during the LVOS campaign. This intrusion, which was profiled by TOPAZ on the night of May 24-25, was also sampled by the NASA Alpha Jet, the Table Mountain ozone lidar, and by an ozonesonde flying above southern California. This event also led to significant ozone increases at surface monitors operated by Clark County, the California Air Resources Board, the U.S. National Park Service, and the Nevada Rural Ozone Initiative (NRVOI), and resulted in exceedances of the 2008 75 ppbv O3 NAAQS both in Clark County and in surrounding areas of Nevada and southern California. The potential implications of this and similar events for air quality compliance in the western U.S. will be discussed.

  3. Stratospheric Ozone destruction by the Bronze-Age Minoan eruption (Santorini Volcano, Greece)

    NASA Astrophysics Data System (ADS)

    Cadoux, Anita; Scaillet, Bruno; Bekki, Slimane; Oppenheimer, Clive; Druitt, Timothy H.

    2015-07-01

    The role of volcanogenic halogen-bearing (i.e. chlorine and bromine) compounds in stratospheric ozone chemistry and climate forcing is poorly constrained. While the 1991 eruption of Pinatubo resulted in stratospheric ozone loss, it was due to heterogeneous chemistry on volcanic sulfate aerosols involving chlorine of anthropogenic rather than volcanogenic origin, since co-erupted chlorine was scavenged within the plume. Therefore, it is not known what effect volcanism had on ozone in pre-industrial times, nor what will be its role on future atmospheres with reduced anthropogenic halogens present. By combining petrologic constraints on eruption volatile yields with a global atmospheric chemistry-transport model, we show here that the Bronze-Age ‘Minoan’ eruption of Santorini Volcano released far more halogens than sulfur and that, even if only 2% of these halogens reached the stratosphere, it would have resulted in strong global ozone depletion. The model predicts reductions in ozone columns of 20 to >90% at Northern high latitudes and an ozone recovery taking up to a decade. Our findings emphasise the significance of volcanic halogens for stratosphere chemistry and suggest that modelling of past and future volcanic impacts on Earth’s ozone, climate and ecosystems should systematically consider volcanic halogen emissions in addition to sulfur emissions.

  4. Stratospheric Ozone destruction by the Bronze-Age Minoan eruption (Santorini Volcano, Greece).

    PubMed

    Cadoux, Anita; Scaillet, Bruno; Bekki, Slimane; Oppenheimer, Clive; Druitt, Timothy H

    2015-07-24

    The role of volcanogenic halogen-bearing (i.e. chlorine and bromine) compounds in stratospheric ozone chemistry and climate forcing is poorly constrained. While the 1991 eruption of Pinatubo resulted in stratospheric ozone loss, it was due to heterogeneous chemistry on volcanic sulfate aerosols involving chlorine of anthropogenic rather than volcanogenic origin, since co-erupted chlorine was scavenged within the plume. Therefore, it is not known what effect volcanism had on ozone in pre-industrial times, nor what will be its role on future atmospheres with reduced anthropogenic halogens present. By combining petrologic constraints on eruption volatile yields with a global atmospheric chemistry-transport model, we show here that the Bronze-Age 'Minoan' eruption of Santorini Volcano released far more halogens than sulfur and that, even if only 2% of these halogens reached the stratosphere, it would have resulted in strong global ozone depletion. The model predicts reductions in ozone columns of 20 to >90% at Northern high latitudes and an ozone recovery taking up to a decade. Our findings emphasise the significance of volcanic halogens for stratosphere chemistry and suggest that modelling of past and future volcanic impacts on Earth's ozone, climate and ecosystems should systematically consider volcanic halogen emissions in addition to sulfur emissions.

  5. Stratospheric Ozone destruction by the Bronze-Age Minoan eruption (Santorini Volcano, Greece)

    PubMed Central

    Cadoux, Anita; Scaillet, Bruno; Bekki, Slimane; Oppenheimer, Clive; Druitt, Timothy H.

    2015-01-01

    The role of volcanogenic halogen-bearing (i.e. chlorine and bromine) compounds in stratospheric ozone chemistry and climate forcing is poorly constrained. While the 1991 eruption of Pinatubo resulted in stratospheric ozone loss, it was due to heterogeneous chemistry on volcanic sulfate aerosols involving chlorine of anthropogenic rather than volcanogenic origin, since co-erupted chlorine was scavenged within the plume. Therefore, it is not known what effect volcanism had on ozone in pre-industrial times, nor what will be its role on future atmospheres with reduced anthropogenic halogens present. By combining petrologic constraints on eruption volatile yields with a global atmospheric chemistry-transport model, we show here that the Bronze-Age ‘Minoan’ eruption of Santorini Volcano released far more halogens than sulfur and that, even if only 2% of these halogens reached the stratosphere, it would have resulted in strong global ozone depletion. The model predicts reductions in ozone columns of 20 to >90% at Northern high latitudes and an ozone recovery taking up to a decade. Our findings emphasise the significance of volcanic halogens for stratosphere chemistry and suggest that modelling of past and future volcanic impacts on Earth’s ozone, climate and ecosystems should systematically consider volcanic halogen emissions in addition to sulfur emissions. PMID:26206616

  6. Stratospheric Ozone destruction by the Bronze-Age Minoan eruption (Santorini Volcano, Greece).

    PubMed

    Cadoux, Anita; Scaillet, Bruno; Bekki, Slimane; Oppenheimer, Clive; Druitt, Timothy H

    2015-01-01

    The role of volcanogenic halogen-bearing (i.e. chlorine and bromine) compounds in stratospheric ozone chemistry and climate forcing is poorly constrained. While the 1991 eruption of Pinatubo resulted in stratospheric ozone loss, it was due to heterogeneous chemistry on volcanic sulfate aerosols involving chlorine of anthropogenic rather than volcanogenic origin, since co-erupted chlorine was scavenged within the plume. Therefore, it is not known what effect volcanism had on ozone in pre-industrial times, nor what will be its role on future atmospheres with reduced anthropogenic halogens present. By combining petrologic constraints on eruption volatile yields with a global atmospheric chemistry-transport model, we show here that the Bronze-Age 'Minoan' eruption of Santorini Volcano released far more halogens than sulfur and that, even if only 2% of these halogens reached the stratosphere, it would have resulted in strong global ozone depletion. The model predicts reductions in ozone columns of 20 to >90% at Northern high latitudes and an ozone recovery taking up to a decade. Our findings emphasise the significance of volcanic halogens for stratosphere chemistry and suggest that modelling of past and future volcanic impacts on Earth's ozone, climate and ecosystems should systematically consider volcanic halogen emissions in addition to sulfur emissions. PMID:26206616

  7. Effect of vibrationally excited oxygen on ozone production in the stratosphere

    SciTech Connect

    Patten, K.O. Jr.; Connell, P.S.; Kinnison, D.E.; Wuebbles, D.J.; Slanger, T.G.; Froidevaux, L.

    1994-01-20

    Photolysis of vibrationally excited oxygen produced by ultraviolet photolysis of ozone in the upper stratosphere is incorporated into the Lawrence Livermore National Laboratory two-dimensional zonally averaged chemical-radiative-transport model of the troposphere and stratosphere. The importance of this potential contributor of odd oxygen to the concentration of ozone is evaluated based on recent information on vibrational distributions of excited oxygen and on preliminary studies of energy transfer from the excited oxygen. When energy transfer rate constants similar to those of Toumi et al. (1991) are assumed, increases in model ozone concentrations of up to 4.0% in the upper stratosphere are found, and the model ozone concentrations are found to agree slightly better with measurements, including recent data from the Upper Atmosphere Research Satellite. However, the ozone increase is only 0.3% when the larger energy transfer rate constants indicated by recent experimental work are applied to the model. An ozone increase of 1% at 50 km requires energy transfer rate constants one-twentieth those of the preliminary observations. As a result, vibrationally excited oxygen processes probably do not contribute enough ozone to be significant in models of the upper stratosphere. 41 refs., 10 figs., 3 tabs.

  8. Effect of vibrationally excited oxygen on ozone production in the stratosphere

    NASA Technical Reports Server (NTRS)

    Patten, K. O., Jr.; Connell, P. S.; Kinnison, D. E.; Wuebbles, D. J.; Slanger, T. G.; Froidevaux, L.

    1994-01-01

    Photolysis of vibrationally excited oxygen produced by ultraviolet photolysis of ozone in the upper stratosphere is incorporated into the Lawrence Livermore National Laboratory two-dimensional zonally averaged chemical-radiative-transport model of the troposphere and stratosphere. The importance of this potential contributor of odd oxygen to the concentration of ozone is evaluated based on recent information on vibrational distributions of excited oxygen and on preliminary studies of energy transfer from the excited oxygen. When energy transfer rate constants similar to those of Toumi et al. (1991) are assumed, increases in model ozone concentrations of up to 4.0% in the upper stratosphere are found, and the model ozone concentrations are found to agree slightly better with measurements, including recent data from the Upper Atmosphere Research Satellite. However, the ozone increase is only 0.3% when the larger energy transfer rate constants indicated by recent experimental work are applied to the model. An ozone increase of 1% at 50 km requires energy transfer rate constants one-twentieth those of the preliminary observations. As a result, vibrationally excited oxygen processes probably do not contribute enough ozone to be significant in models of the upper stratosphere.

  9. The impact of high altitude aircraft on the ozone layer in the stratosphere

    NASA Technical Reports Server (NTRS)

    Tie, Xue XI; Brasseur, Guy; Lin, Xing; Friedlingstein, P.; Granier, Claire; Rasch, Philip

    1994-01-01

    The paper discusses the potential effects on the ozone layer of gases released by the engines of proposed high altitude supersonic aircraft. The major problem arises from the emissions of nitrogen oxides which have the potential to destroy significant quantities of ozone in the stratosphere. The magnitude of the perturbation is highly dependent on the cruise altitude of the aircraft. Furthermore, the depletion of ozone is substantially reduced when heterogeneous conversion of nitrogen oxides into nitric acid on sulfate aerosol particles is taken into account in the calculation. The sensitivity of the aerosol load on stratospheric ozone is investigated. First, the model indicates that the aerosol load induced by the SO2 released by aircraft is increased by about 10-20% above the background aerosols at mid-high latitude of the Northern Hemisphere at 15 km for the NASA emission scenario A (the NASA emission scenarios are explained in Tables I to III). This increase in aerosol has small effects on stratospheric ozone. Second, when the aerosol load is increased following a volcanic eruption similar to the eruption of El Chichon (Mexico, April 1982), the ozone column in spring increases by as much as 9% in response to the injection of NOx from the aircraft with the NASA emission scenario A. Finally, the modeled suggests that significant ozone depletion could result from the formation of additional polar stratospheric clouds produced by the injection of H2O and HNO3 by the aircraft engines.

  10. Stratospheric cooling and polar ozone loss due to H2 emissions of a global hydrogen economy

    NASA Astrophysics Data System (ADS)

    Feck, T.; Grooß, J.-U.; Riese, M.; Vogel, B.

    2009-04-01

    "Green" hydrogen is seen as a major element of the future energy supply to reduce greenhouse gas emissions substantially. However, due to the possible interactions of hydrogen (H2) with other atmospheric constituents there is a need to analyse the implications of additional atmospheric H2 that could result from hydrogen leakage of a global hydrogen infrastructure. Emissions of molecular H2 can occur along the whole hydrogen process chain which increase the tropospheric H2 burden. Across the tropical tropopause H2 reaches the stratosphere where it is oxidised and forms water vapour (H2O). This causes increased IR-emissions into space and hence a cooling of the stratosphere. Both effects, the increase of stratospheric H2O and the cooling, enhances the potential of chlorine activation on liquid sulfate aerosol and polar stratospheric clouds (PSCs), which increase polar ozone destruction. Hence a global hydrogen economy could provoke polar ozone loss and could lead to a substantial delay of the current projected recovery of the stratospheric ozone layer. Our investigations show that even if 90% of the current global fossil primary energy input could be replaced by hydrogen and approximately 9.5% of the product gas would leak to the atmosphere, the ozone loss would be increased between 15 to 26 Dobson Units (DU) if the stratospheric CFC loading would retain unchanged. A consistency check of the used approximation methods with the Chemical Lagrangian Model of the Stratosphere (CLaMS) shows that this additional ozone loss can probably be treated as an upper limit. Towards more realistic future H2 leakage rate assumptions (< 3%) the additional ozone loss would be rather small (? 10 DU). However, in all cases the full damage would only occur if stratospheric CFC-levels would retain unchanged. Due to the CFC-prohibition as a result of the Montreal Protocol the forecasts suggest a decline of the stratospheric CFC loading about 50% until 2050. In this case our calculations

  11. 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.

  12. Drivers of changes in stratospheric and tropospheric ozone between year 2000 and 2100

    NASA Astrophysics Data System (ADS)

    Banerjee, Antara; Maycock, Amanda C.; Archibald, Alexander T.; Abraham, N. Luke; Telford, Paul; Braesicke, Peter; Pyle, John A.

    2016-03-01

    A stratosphere-resolving configuration of the Met Office's Unified Model (UM) with the United Kingdom Chemistry and Aerosols (UKCA) scheme is used to investigate the atmospheric response to changes in (a) greenhouse gases and climate, (b) ozone-depleting substances (ODSs) and (c) non-methane ozone precursor emissions. A suite of time-slice experiments show the separate, as well as pairwise, impacts of these perturbations between the years 2000 and 2100. Sensitivity to uncertainties in future greenhouse gases and aerosols is explored through the use of the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. The results highlight an important role for the stratosphere in determining the annual mean tropospheric ozone response, primarily through stratosphere-troposphere exchange (STE) of ozone. Under both climate change and reductions in ODSs, increases in STE offset decreases in net chemical production and act to increase the tropospheric ozone burden. This opposes the effects of projected decreases in ozone precursors through measures to improve air quality, which act to reduce the ozone burden. The global tropospheric lifetime of ozone (τO3) does not change significantly under climate change at RCP4.5, but it decreases at RCP8.5. This opposes the increases in τO3 simulated under reductions in ODSs and ozone precursor emissions. The additivity of the changes in ozone is examined by comparing the sum of the responses in the single-forcing experiments to those from equivalent combined-forcing experiments. Whilst the ozone responses to most forcing combinations are found to be approximately additive, non-additive changes are found in both the stratosphere and troposphere when a large climate forcing (RCP8.5) is combined with the effects of ODSs.

  13. A global climatology of tropospheric and stratospheric ozone derived from Aura OMI and MLS measurements

    NASA Astrophysics Data System (ADS)

    Ziemke, J. R.; Chandra, S.; Labow, G. J.; Bhartia, P. K.; Froidevaux, L.; Witte, J. C.

    2011-09-01

    A global climatology of tropospheric and stratospheric column ozone is derived by combining six years of Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone measurements for the period October 2004 through December 2010. The OMI/MLS tropospheric ozone climatology exhibits large temporal and spatial variability which includes ozone accumulation zones in the tropical south Atlantic year-round and in the subtropical Mediterranean/Asia region in summer months. High levels of tropospheric ozone in the Northern Hemisphere also persist in mid-latitudes over the eastern part of the North American continent extending across the Atlantic Ocean and the eastern part of the Asian continent extending across the Pacific Ocean. For stratospheric ozone climatology from MLS, largest column abundance is in the Northern Hemisphere in the latitude range 70° N-80° N in February-April and in the Southern Hemisphere around 40° S-50° S during August-October. Largest stratospheric ozone lies in the Northern Hemisphere and extends from the eastern Asian continent eastward across the Pacific Ocean and North America. With the advent of many newly developing 3-D chemistry and transport models it is advantageous to have such a dataset for evaluating the performance of the models in relation to dynamical and photochemical processes controlling the ozone distributions in the troposphere and stratosphere. The OMI/MLS gridded ozone climatology data are made available to the science community via the NASA Goddard Space Flight Center ozone and air quality website http://ozoneaq.gsfc.nasa.gov/.

  14. Trends in stratospheric ozone derived from merged SAGE II and Odin-OSIRIS satellite observations

    NASA Astrophysics Data System (ADS)

    Bourassa, A. E.; Degenstein, D. A.; Randel, W. J.; Zawodny, J. M.; Kyrölä, E.; McLinden, C. A.; Sioris, C. E.; Roth, C. Z.

    2014-03-01

    Stratospheric ozone profile measurements from the Stratospheric Aerosol and Gas Experiment (SAGE) II satellite instrument (1984-2005) are combined with those from the Optical Spectrograph and InfraRed Imager System (OSIRIS) instrument on the Odin satellite (2001-Present) to quantify interannual variability and decadal trends in stratospheric ozone between 60° S and 60° N. These data are merged into a multi-instrument, long-term stratospheric ozone record (1984-present) by analyzing the measurements during the overlap period of 2002-2005 when both satellite instruments were operational. The variability in the deseasonalized time series is fit using multiple linear regression with predictor basis functions including the quasi-biennial oscillation, El Niño-Southern Oscillation index, solar activity proxy, and the pressure at the tropical tropopause, in addition to two linear trends (one before and one after 1997), from which the decadal trends in ozone are derived. From 1984-1997, there are statistically significant negative trends of 5-10% per decade throughout the stratosphere between approximately 30-50 km. From 1997-present, a statistically significant recovery of 3-8% per decade has taken place throughout most of the stratosphere with the notable exception between 40° S-40° N below approximately 22 km where the negative trend continues. The recovery is not significant between 25-35 km altitude when accounting for a conservative estimate of instrument drift.

  15. Trends in stratospheric ozone derived from merged SAGE II and Odin-OSIRIS satellite observations

    NASA Astrophysics Data System (ADS)

    Bourassa, A. E.; Degenstein, D. A.; Randel, W. J.; Zawodny, J. M.; Kyrölä, E.; McLinden, C. A.; Sioris, C. E.; Roth, C. Z.

    2014-07-01

    Stratospheric ozone profile measurements from the Stratospheric Aerosol and Gas Experiment~(SAGE) II satellite instrument (1984-2005) are combined with those from the Optical Spectrograph and InfraRed Imager System (OSIRIS) instrument on the Odin satellite (2001-Present) to quantify interannual variability and decadal trends in stratospheric ozone between 60° S and 60° N. These data are merged into a multi-instrument, long-term stratospheric ozone record (1984-present) by analyzing the measurements during the overlap period of 2002-2005 when both satellite instruments were operational. The variability in the deseasonalized time series is fit using multiple linear regression with predictor basis functions including the quasi-biennial oscillation, El Niño-Southern Oscillation index, solar activity proxy, and the pressure at the tropical tropopause, in addition to two linear trends (one before and one after 1997), from which the decadal trends in ozone are derived. From 1984 to 1997, there are statistically significant negative trends of 5-10% per decade throughout the stratosphere between approximately 30 and 50 km. From 1997 to present, a statistically significant recovery of 3-8% per decade has taken place throughout most of the stratosphere with the notable exception between 40° S and 40° N below approximately 22 km where the negative trend continues. The recovery is not significant between 25 and 35 km altitudes when accounting for a conservative estimate of instrument drift.

  16. Relationships among Brewer-Dobson circulation, double tropopauses, ozone and lower-stratospheric water vapor

    NASA Astrophysics Data System (ADS)

    Castanheira, J. M.; Peevey, T. R.; Marques, C. A. F.; Olsen, M. A.

    2012-04-01

    This communication will discuss the statistical relationships between the variability of the area covered by double tropopause events and the variabilities of total column ozone and of lower-stratospheric water vapor. The QBO signal in double tropopause events statistics and the relationship between tropical upwelling and the near global (50oS - 50oN) lower stratospheric water vapour will be also presented. The analysis is based on both reanalysis data (ERA-Interim) and satellite data. Significant correlations were found between the area covered by double tropopause events in the latitudinal band 20 - 65oN and the gradient of total column ozone in the subtropical Northern Hemisphere. Significant correlations were also found between de global area of double tropopause events and the near global (50oS - 50oN) water vapour in the lower stratosphere. The relationship between double tropopause events and lower stratospheric ozone is detailed by a correlation analysis between the frequencies of ozone laminae and double tropopause events as found in the HIRDLS data. The correlations of DT variables with total column ozone and ozone laminae are both consistent with intrusion events of tropospheric tropical air into the lower extratropical stratosphere, with the tropical tropopause overlaying the extratropical one. The poleward excursions of the tropical tropopause are also consistent with the found negative correlation between the area extension of DTs and the near global lower stratospheric water vapour. Finally, we will show the existence of a significant negative correlation between the tropical upwelling, determined using the "downward control principle", and the near global lower stratospheric water vapor.

  17. 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.

  18. Southern America stratospheric ozone variation during the last decade (1996-2005)

    NASA Astrophysics Data System (ADS)

    Imai, T.; Martin, I.; Iha, K.; Souza, S.

    Stratospheric ozone variation in the last decade reveals important dynamics of environmental areas in Brazil possible to be correlated with natural disasters like droughts in the Amazon region and the first hurricane observed in Santa Catarina at sea temperatures bellow 22 r C in South America A team of 74 ozone specialists lead by Prof Fahey from 1965 to 2001 elaborated a very well known graphic The graphic shows that the global ozone remained constant from 1965 to 1980 with 3 000 megatons of Global Ozone when it started to quickly decline in approximately 3 or 80 megatons per year In 2001 more than 50 of the ozone was depleted IPCC specialists recognize the ozone depletion of Fahey studies in the IPCC 2001 8-1 decision the Climate Change and the Ozone Depletion In 2002 Fahey s works went through a deep methodological conference being approved by 44 more specialists in Atmospheric Chemistry in Les Diabretes Switzerland The ozone hole after 1985 reached about 27 millions km 2 or 5 of the surface of the Planet and there practically all the stratospheric ozone annually disappeared in the beginning of October Projecting these figures until 2005 we reached 70 when Katrina Hurricane and Amazons River drought happens and in 2015 the depletion will reach 100 But between 2003 and 2005 the IPCC using the same graphic and exchanging the annual loss of ozone quota for deviation specialist starts saying that the problem will be solved in 2050 That the biggest deviation of --5 was in 1993

  19. On the ambiguous nature of the 11-year solar cycle signal profile in stratospheric ozone

    NASA Astrophysics Data System (ADS)

    Dhomse, Sandip; Chipperfield, Martyn; Damadeo, Robert; Zawodny, Joe; Ball, William; Feng, Wuhu; Hossaini, Ryan; Mann, Graham; Haigh, Joana

    2016-04-01

    We use three satellite datasets and simulations from a 3-D chemical transport model, forced by three different solar flux datasets, to diagnose the 11-year solar cycle signal (SCS) in stratospheric ozone. Our analysis shows that compared to SAGE II v6.2, a reduced upper stratospheric SCS in SAGE II v7.0 is due to a more realistic ozone-temperature anti-correlation. Overall, all model simulations show a positive SCS in the lower and middle stratosphere and negligible SCS in the upper stratosphere in agreement with SAGE v7.0, HALOE and MLS data. The model simulations show a differently structured SCS over different time periods covered by the satellite datasets, which helps to resolve some observed differences. However, despite the improvements to the SAGE II data, due to remaining biases in current observational and reanalysis datasets, accurate quantification of the influence of solar flux variability on the climate system remains an open scientific question.

  20. Laboratory Studies of Chemical and Photochemical Processes Relevant to Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Zahniser, Mark S.; Nelson, David D.; Worsnop, Douglas R.; Kolb, Charles E.

    1996-01-01

    The purpose of this project is to reduce the uncertainty in several key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring rate coefficients and product channels for reactions of HOx and NOx species in the temperature range 200 K to 240 K relevant to the lower stratosphere. Other areas of study have included infrared spectroscopic studies of the HO radical, measurements of OH radical reactions with alternative fluorocarbons, and determination of the vapor pressures of nitric acid hydrates under stratospheric conditions. The results of these studies will improve models of stratospheric ozone chemistry and predictions of perturbations due to human influences.

  1. Recent lidar measurements of stratospheric ozone and temperature within the network for the detection of stratospheric change

    NASA Technical Reports Server (NTRS)

    Mcgee, Thomas J.; Ferrare, Richard; Butler, James J.; Frost, Robert L.; Gross, Michael; Margitan, James

    1991-01-01

    The Goddard mobile lidar was deployed at Cannon Air Force Base near Clovis, New Mexico during the Spring of 1990. Measurements of stratospheric ozone and temperature were made over a period of six weeks. Data from the lidar system is compared with data from a balloon-borne, ultraviolet instrument launched from nearby Ft. Sumner, New Mexico. Along with several improvements to this instrument which are now underway, a second lidar dedicated to temperature and aerosol measurements is now being developed.

  2. 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.

  3. Decline in the tropospheric abundance of halogen from halocarbons: Implications for stratospheric ozone depletion

    SciTech Connect

    Montzka, S.A.; Butler, J.H.; Myers, R.C.

    1996-05-31

    Analyses of air sampled from remote locations across the globe reveal that tropospheric chlorine attributable to anthropogenic halocarbons peaked near the beginning of 1994 and was decreasing at a rate of 25 {+-} parts per trillion per year by mid-1995. Although bromine from halons was still increasing in mid-1995, the summed abundance of these halogens in the troposphere is decreasing. To assess the effect of this trend on stratospheric ozone, estimates of the future stratospheric abundance of ozone-depleting gases were made for mid-latitude and polar regions on the basis of these tropospheric measurements. These results suggest that the amount of reactive chlorine and bromine will reach a maximum in the stratosphere between 1997 and 1999 and will decline thereafter if limits outlined in the adjusted and amended Montreal Protocol on Substances That Deplete the Ozone Layer are not exceeded in future years. 30 refs., 4 figs., 1 tab.

  4. 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. PMID:26593823

  5. Decline in the Tropospheric Abundance of Halogen from Halocarbons: Implications for Stratospheric Ozone Depletion

    PubMed

    Montzka; Butler; Myers; Thompson; Swanson; Clarke; Lock; Elkins

    1996-05-31

    Analyses of air sampled from remote locations across the globe reveal that tropospheric chlorine attributable to anthropogenic halocarbons peaked near the beginning of 1994 and was decreasing at a rate of 25 ± 5 parts per trillion per year by mid-1995. Although bromine from halons was still increasing in mid-1995, the summed abundance of these halogens in the troposphere is decreasing. To assess the effect of this trend on stratospheric ozone, estimates of the future stratospheric abundance of ozone-depleting gases were made for mid-latitude and polar regions on the basis of these tropospheric measurements. These results suggest that the amount of reactive chlorine and bromine will reach a maximum in the stratosphere between 1997 and 1999 and will decline thereafter if limits outlined in the adjusted and amended Montreal Protocol on Substances That Deplete the Ozone Layer are not exceeded in future years.

  6. A global analysis of the ozone deficit in the upper stratosphere and lower mesosphere

    NASA Technical Reports Server (NTRS)

    Eluszkiewicz, Janusz; Allen, Mark

    1993-01-01

    The global measurements of temperature, ozone, water vapor, and nitrogen dioxide acquired by the Limb Infrared Monitor of the Stratosphere (LIMS), supplemented by a precomputed distribution of chlorine monoxide, are used to test the balance between odd oxygen production and loss in the upper stratosphere and lower mesosphere. An efficient photochemical equilibrium model, whose validity is ascertained by comparison with the results from a fully time-dependent one-dimensional model at selected latitudes, is used in the calculations. The computed ozone abundances are systematically lower than observations for May 1-7, 1979, which suggests, contrary to the conclusions of other recent studies, a real problem in model simulations of stratospheric ozone.

  7. The dynamics of the stratospheric polar vortex and its relation to springtime ozone depletions

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.; Hartmann, Dennis L.

    1991-01-01

    Recent aircraft observations have determined the structure of polar vortices during winter and their relationship to polar ozone depletions, based on high dynamical isolation and the extremely low temperatures required for stratospheric cloud formation. The aircraft data reveal large gradients of potential vorticity and concentrations of conservative trace species at the transition from high-latitude to polar air, implying that the inward mixing of heat and constituents is strongly inhibited, and that the perturbed polar stratospheric chemistry associated with the ozone hole is isolated from the rest of the stratosphere until the vortex breaks up in late spring. It is therefore the overall polar vortex which limits the annual polar ozone depletions' maximum area-coverage.

  8. A Long Data Record (1979-2003) of Stratospheric Ozone Derived from TOMS Cloud Slicing: Comparison with SAGE and Implications for Ozone Recovery

    NASA Technical Reports Server (NTRS)

    Ziemke, Jerry R.; Chandra, Sushil; Bhartia, Pawan K.

    2004-01-01

    It is generally recognized that Stratospheric Aerosols and Gas Experiment (SAGE) stratospheric ozone data have become a standard long-record reference field for comparison with other stratospheric ozone measurements. This study demonstrates that stratospheric column ozone (SCO) derived from total ozone mapping spectrometer (TOMS) Cloud Slicing may be used to supplement SAGE data as a stand-alone long- record reference field in the tropics extending to middle and high latitudes over the Pacific. Comparisons of SAGE I1 version 6.2 SCO and TOMS version 8 Cloud Slicing SCO for 1984-2003 exhibit remarkable agreement in monthly ensemble means to within 1-3 DU (1 - 1.5% of SCO) despite being independently-calibrated measurements. An important component of our study is to incorporate these column ozone measurements to investigate long-term trends for the period 1979-2003. Our study includes Solar Backscatter Ultraviolet (SBW) version 8 measurements of upper stratospheric column ozone (i.e., zero to 32 hPa column ozone) to characterize seasonal cycles and seasonal trends in this region, as well as the lower stratosphere and troposphere when combined with TOMS SCO and total column ozone. The trend analyses suggest that most ozone reduction in the atmosphere since 1979 in mid-to-high latitudes has occurred in the Lower stratosphere below approx. 25 km. The delineation of upper and lower stratospheric column ozone indicate that trends in the upper stratosphere during the latter half of the 1979-2003 period have reduced to near zero globally, while trends in the lower stratosphere have become larger by approx. 5 DU decade%om the tropics extending to mid-latitudes in both hemispheres. For TCO, the trend analyses suggest moderate increases over the 25-year time record in the extra-tropics of both hemispheres of around 4-6 DU (Northern Hemisphere) and 6-8 DU (Southern Hemisphere).

  9. Simulation of Stratospheric Ozone in the KIAPSGM NWP model using linear photochemistry parameterization

    NASA Astrophysics Data System (ADS)

    Jeong, G. R.; Monge-Sanz, B.; Cariolle, D.; Lee, E. H.; Jin, E. K.

    2014-12-01

    Stratospheric ozone plays important roles in the Earth's weather and climate systems due to its physiochemical properties and a wide range of spectral absorption. Because of complicated chemical equations and expensive computational cost, NWP community has introduced a linear photochemistry parameterization (LPP) that Cariolle and Déqué suggested in 1986 with an insight of ozone-temperature relationships, to weather forecasting system. In this study, we simulated stratospheric ozone using recent LPP coefficients in a numerical weather prediction (NWP) model, the KIAPS-GM (Korea Institute of Atmospheric Prediction Systems - Global Model), and evaluated model results with observations. The KIAPS-GM uses three dimensional hydrostatic dynamical core based on the High-Order Method Modeling Environment (HOMME) in cubed sphere with a horizontal resolution of ne30np4 and 70 vertical layers up to 85km. LPP scheme was fully implemented into the KIAPS-GM including the ozone tracer advection. Prognostic ozone was estimated through interaction with local ozone field, temperature field, and radiation field as those physics fields were updated while climatological ozone (Fortuin and Kelder, 1998) was constantly fed into radiation fields in every month. ERA-interim ozone and meteorological data (Dee et al., 2011) were used as initial data. Simulation period was year 2008 when larger ozone hole events occurred than usual. We compared interactive ozone case with climatological ozone case. For the sensitivity studies to initial ozone fields and LPP coefficients, ERA-interim hourly and monthly ozone data were used; and LPP coefficients such as Cariolle and Teyssadre (2007) and Monge-Sanz et al. (2011) were interpolated into instantaneous pressure levels, respectively. Preliminary results show that the ozone concentration in interactive ozone case is higher than climatological one in the lower stratosphere and troposphere while the former is lower than the latter in the upper

  10. Implications of smaller concentrations of stratospheric OH - A two-dimensional model study of ozone perturbations

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Borucki, W. J.; Woodward, H. T.; Capone, L. A.; Riegel, C. A.; Turco, R. P.; Poppoff, I. G.; Santhanam, K.

    1981-01-01

    There is growing observational evidence that stratospheric OH concentrations are smaller than models have been predicting. Using very recent HOx reaction rate coefficient measurements in a two-dimensional photochemical model, results which support these observations are obtained. As a consequence of smaller OH concentrations, we show that perturbations of stratospheric ozone by NOx (SST emissions and nitrogen fertilizers) may be larger than expected, while perturbations due to added water vapor and chlorine (SSTs and chlorofluoromethanes, respectively) may be smaller.

  11. Unraveling the empirical relationship between Arctic stratospheric ozone loss and temperature

    NASA Astrophysics Data System (ADS)

    von Hobe, Marc; Grooß, Jens-Uwe; Müller, Rolf

    2014-05-01

    Ever since the discovery of the Antarctic ozone hole it has been recognized that cold temperatures play a key role in fostering strong ozone depletion in the polar stratosphere. Compact negative correlations between total winter ozone loss and vortex area exposed to temperatures below certain threshold values have been demonstrated (e.g. Harris et al., 2010; Rex et al., 2006; Rex et al., 2004). The most commonly used threshold is the NAT equilibrium temperature, but other choices have been suggested, such as the temperature when the rate of chlorine activation on liquid aerosols exceeds a certain limit. Interestingly, both thresholds relate to critical temperatures in the context of heterogeneous chlorine activation, and Harris et al., 2010, stated that original activation (i.e. the activation in early winter) is the most important factor influencing ozone loss. But at least two other key processes - catalytic ozone loss and denitrification - depend directly on temperature, and temperature also controls the stability and therefore the persistence of the polar vortex. Here, we investigate such "vortex area" correlations for a number of different temperature thresholds, as well as direct correlations with vortex mean temperature and with the date of the final warming. We also carry out sensitivity studies using the Chemical Lagrangian Model of the Stratosphere (CLaMS) to investigate the response of ozone loss to temperature modifications for particle formation and growth, surface reaction probabilities and gas phase reactivity separately. Rex et al., Arctic ozone loss and climate change, Geophys. Res. Lett., 31, L04116, 2004. Rex et al., Arctic winter 2005: Implications for stratospheric ozone loss and climate change, Geophys. Res. Lett., 33, L23808, 2006. Harris et al., A closer look at Arctic ozone loss and polar stratospheric clouds, Atmos. Chem. Phys., 10, 8499-8510, 2010.

  12. 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.

  13. Relationship between ozone and temperature trends in the lower stratosphere: Latitude and seasonal dependences

    NASA Technical Reports Server (NTRS)

    Mccormack, John P.; Hood, Lon L.

    1994-01-01

    A one-dimensional radiative transfer model with fixed dynamical heating is used to calculate the approximate latitude and seasonal dependences of lower stratospheric temperature changes associated with observed ozone trends. The spatial and temporal distribution of ozone profile trends in the lower stratosphere is estimated from a combination of Nimbus 7 Solar Backscattered Ultraviolet (SBUV) global measurements of the ozone column below 32 mbar for the period 1979-1990 and balloon ozonesonde profile trends at northern middle latitudes. The calculated temperature trends near 100 mbar compare favorably with those recently derived by Randel and Cobb (1994) using data from Channel 4 of the Microwave Sounding Unit (MSU) on the NOAA operational satellites, although a number of quantitative differences are found. An independent analysis reported here of 100 mbar temperatures derived from northern hemisphere radiosonde data at the Free University of Berlin (FUB) supports the validity of the satellite-derived lower stratospheric temperature trends. These results are therefore generally consistent with the hypothesis that observed lower stratospheric cooling trends are predominantly determined by reductions in radiative heating associated with stratospheric ozone depletion.

  14. Solar variations and their influence on trends in upper stratospheric ozone and temperature

    SciTech Connect

    Wuebbles, D.J.; Kinnison, D.E. ); Lean, J.L. . E.O. Hulburt Center for Space Research)

    1990-10-01

    Over the past decade, knowledge of the magnitude and temporal structure of the variations in the sun's ultraviolet irradiance has increased steadily. A number of theoretical modeling studies have shown that changes in the solar ultraviolet flux during the 11-year solar cycle can have a significant effect on stratospheric ozone concentrations. With the exception of Brasseur et al., who examined a very broad range of solar flux variations, all of these studies assumed much larger changes in the ultraviolet flux than measurements now indicate. These studies either calculated the steady-state effect at solar maximum and solar minimum or assumed sinusoidal variations in the solar flux changes with time. It is now possible to narrow the uncertainty range of the expected effects on upper stratospheric ozone and temperature resulting from the 11-year solar cycle. A more accurate representation of the solar flux changes with time is used in this analysis, as compared to previous published studies. This study also evaluates the relative roles of solar flux variations and increasing concentrations of long-lived trace gases in determining the observed trends in upper stratospheric ozone and temperature. The LLNL two-dimensional chemical-radiative-transport model of the global atmosphere is used to evaluate the combined effects on the stratosphere from changes in solar ultraviolet irradiances and trace gas concentrations over the last several decades. Derived trends in upper stratospheric ozone concentrations and temperature are then compared with available analyses of ground-based and satellite measurements over this time period.

  15. Effect of stratospheric aerosol layers on the TOMS/SBUV ozone retrieval

    NASA Technical Reports Server (NTRS)

    Torres, O.; Ahmad, Zia; Pan, L.; Herman, J. R.; Bhartia, P. K.; Mcpeters, R.

    1994-01-01

    An evaluation of the optical effects of stratospheric aerosol layers on total ozone retrieval from space by the TOMS/SBUV type instruments is presented here. Using the Dave radiative transfer model we estimate the magnitude of the errors in the retrieved ozone when polar stratospheric clouds (PSC's) or volcanic aerosol layers interfere with the measurements. The largest errors are produced by optically thick water ice PSC's. Results of simulation experiments on the effect of the Pinatubo aerosol cloud on the Nimbus-7 and Meteor-3 TOMS products are presented.

  16. Millimeter-wave ozone measurements for the network for the detection of stratospheric change

    NASA Technical Reports Server (NTRS)

    Connor, Brian J.; Parrish, Alan

    1990-01-01

    The primary research objective is to initiate long-term monitoring of stratospheric ozone with a ground-based millimeter-wave spectrometer, the first of several such instruments projected to be part of the Network for the Detection of Stratospheric Change. The ultimate goal of this monitoring is twofold. First, to detect any secular trend in stratospheric ozone abundance, whether of natural or anthropogenic origin and, second, to provide ground-truth validation for existing and future satellite measurements of ozone. With this goal in mind, a more immediate objective is to validate the millimeter-wave measurements by tests of the instrument, internal consistency tests on the data, and most importantly, by intercomparison with all other available ozone measurements. The validation process is expected to lead to refinements in the instrument and its operating procedures and in the data analysis. The final objective is to perform short-term scientific studies with the data, including studies of the ozone diurnal and seasonal variations, and comparison of ozone variations with changes in other geophysical parameters, notably temperature and water vapor. Routine observations are now ongoing; these will allow continuing intercomparisons with the Stratospheric Aerosol and Gas Experiment (SAGE II) and one of the lidars, which is permanently on site. The experience gained during the Stratospheric Ozone Intercomparison (STOIC) caused us to refine our calibration procedures and identify the need for internal shielding of the millimeter receiver from radio frequency interference. Installation of this shielding is planned for the near future and should allow improvements in the instrument calibration and a higher signal-to-noise ratio, both of which will result in improved measurement precision.

  17. 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.

  18. The Effects of Tropical Cirrus Clouds on the Abundance of Lower Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Dessler, A. E.; Minschwaner, K.; Weinstock, E. M.; Hintsa, E. J.; Anderson, J. G.; Russell, J. M., III

    1996-01-01

    The distribution of many chemical constituents of the atmosphere (e.g., ozone) is at least partially determined by the, distribution of net radiative heating in the atmosphere. In this paper, we demonstrate the significant effect of high cirrus clouds on the net radiative heating of the tropical lower stratosphere. A model of tropical lower stratospheric ozone is then used to demonstrate the sensitivity of calculated ozone to the varying cloud cover used in the model. We conclude that calculated ozone is sensitive to the inclusion of clouds in models and that models of the atmosphere should include a realistic description of tropical cirrus clouds in order to accurately simulate the chemical composition of the atmosphere.

  19. The Effects of Tropical Cirrus Clouds on the Abundance of Lower Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Dessler, A. E.; Minschwaner, K.; Weinstock, E. M.; Hintsa, E. J.; Anderson, J. G.; Russell, J. M., III

    1996-01-01

    The distribution of many chemical constituents of the atmosphere (e.g., ozone) is at least partially determined by the. distribution of net radiative heating in the atmosphere. In this paper, we demonstrate the significant effect of high cirrus clouds on the net radiative heating of the tropical lower stratosphere. A model of tropical lower stratospheric ozone is then used to demonstrate the sensitivity of calculated ozone to the varying cloud cover used in the model. We conclude that calculated ozone is sensitive to the inclusion of clouds In models and that models of the atmosphere should include a realistic description of tropical cirrus clouds in order to accurately simulate the chemical composition of the atmosphere.

  20. The Effects of Tropical Cirrus Clouds on the Abundance of Lower Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Dessler, A. E.; Minschwaner, K.; Weinstock, E. M.; Hintsa, E. J.; Anderson, J. G.; Russell, J. M., III

    1996-01-01

    The distribution of many chemical constituents of the atmosphere (e.g., ozone) is at least partially determined by the distribution of net radiative heating in the atmosphere. In this paper, we demonstrate the significant effect of high cirrus clouds on the net radiative heating of the tropical lower stratosphere. A model of tropical lower stratospheric ozone is then used to demonstrate the sensitivity of calculated ozone to the varying cloud cover used in the model. We conclude that calculated ozone is sensitive to the inclusion of clouds in models and that models of the atmosphere should include a realistic description of tropical cirrus clouds in order to accurately simulate the chemical composition of the atmosphere.

  1. 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.

  2. The Latitude Dependence of the Effect of Pinatubo on Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Douglass, Anne R.

    2004-01-01

    Statistical analysis of TOMS and SBLT total ozone data indicate that the eruption of Pinatubo in 1991 led to a significant decrease in ozone at northern midlatitudes with little or no effect at southern midlatitudes. We argue that this puzzling absence of a southern hemisphere effect may be an artifact of the statistical analysis. We have run a 3D CTM simulation of the past 30 years of stratospheric photochemistry with variable forcing due to chlorine/bromine compounds, solar ultraviolet radiation, and volcanic aerosols. This integration used winds from the FVGCM, which has similar interannual variability to the atmosphere. When this CTM output was examined with a standard time-series analysis, we found an effect of Pinatubo in the southern hemisphere, but not in the northern hemisphere. We then reran the CTM without volcanic aerosols. The subtraction of the two simulations indicated that, as expected, that Pinatubo affected both hemispheres in the model. This means that the northern hemisphere effect was in the model but did not show up in the statistical analysis. We also had an on-line parameterized chemical ozone tracer with seasonally repeating production and loss over the simulation. We used this as a dynamical surrogate to remove interannual variability from the original model output. The residual time series was then analyzed for the Pinatubo effect and we were able to find it in both hemispheres. We suggest that the combination of the two volcanoes, El Chichon and Pinatubo, with the solar cycle and interannual variability led to this problem of analysis in the northern hemisphere of our model. We furthermore suggest that a similar think may be occurring in the southern hemisphere of the data. An analysis of the atmosphere's southern hemisphere with a good dynamical surrogate may solve the mystery of the missing southern hemisphere effect of Pinatubo on ozone.

  3. A Status Report on the SHADOZ (Southern Hemisphere Additional Ozonesondes) Project and Some Issues Affecting Ozone Climatology

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Witte, J. C.; McPeters, R. D.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    SHADOZ aims to support the study of local and global patterns in stratospheric and tropospheric ozone and to provide a data set for the validation for satellite products and model calculations of ozone. Southern hemispheric tropical ozone is of particular interest because this region appears to have complex interplay among photochemical ozone formation (from biomass burning and lightning), stratospheric dynamics, convection and possibly cross-hemispheric transport. Balloon-borne ozone instrumentation (ozonesondes), joined with standard radiosondes for measurement of pressure, temperature and relative humidity, is used to collect profiles throughout the troposphere and lower- to mid-stratosphere. A network of 10 southern hemisphere tropical and subtropical stations, called the Southern Hemisphere ADditional OZonesondes (SHADOZ) project, has been established from operational sites to assemble sonde data for 1998-2000. A status report on the archive, with station operating characteristics, will be given, along with some operational issues that may affect data analysis and interpretation.

  4. Model calculations of the relative effects of CFCs and their replacements on stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Fisher, Donald A.; Hales, Charles H.; Filkin, David L.; Ko, Malcolm K. W.; Sze, N. Dak

    1990-01-01

    Because chlorine has been linked to the destruction of stratospheric ozone, the use of many fully halogenated compounds, such as the chlorofluorocarbons CFC-11 and -12, is restricted by international agreement. Hydrohalocarbons are under intensive development as replacements for CFCs. Because they contain hydrogen, these gases are susceptible to tropospheric destruction which significantly shortens their atmospheric lifetimes,. Model calculations show that chlorine-containing hydrohalocarbons have less effect on ozone, by an order of magnitude, than their regulated counterparts.

  5. Large stratospheric sudden warming in Antarctic late winter and shallow ozone hole in 1988

    SciTech Connect

    Kanzawa, Hiroshi; Kawaguchi, Sadao )

    1990-01-01

    There occurred a large stratospheric sudden warming in the southern hemisphere in late winter of 1988 which competes in suddenness and size with major mid-winter warmings in the northern hemisphere. Associated with the dynamical phenomenon of the sudden warming, total ozone increased over the eastern hemispheric part of Antarctica. The sudden warming as well as other warmings which followed it made the 1988 Antarctic ozone hole shallow in depth and small in area.

  6. 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

  7. 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.

  8. Computer model predictions of the local effects of large, solid-fuel rocket motors on stratospheric ozone. Technical report

    SciTech Connect

    Zittel, P.F.

    1994-09-10

    The solid-fuel rocket motors of large space launch vehicles release gases and particles that may significantly affect stratospheric ozone densities along the vehicle's path. In this study, standard rocket nozzle and flowfield computer codes have been used to characterize the exhaust gases and particles through the afterburning region of the solid-fuel motors of the Titan IV launch vehicle. The models predict that a large fraction of the HCl gas exhausted by the motors is converted to Cl and Cl2 in the plume afterburning region. Estimates of the subsequent chemistry suggest that on expansion into the ambient daytime stratosphere, the highly reactive chlorine may significantly deplete ozone in a cylinder around the vehicle track that ranges from 1 to 5 km in diameter over the altitude range of 15 to 40 km. The initial ozone depletion is estimated to occur on a time scale of less than 1 hour. After the initial effects, the dominant chemistry of the problem changes, and new models are needed to follow the further expansion, or closure, of the ozone hole on a longer time scale.

  9. Temperature thresholds for chlorine activation and ozone loss in the polar stratosphere

    NASA Astrophysics Data System (ADS)

    Drdla, K.; Müller, R.

    2012-07-01

    Low stratospheric temperatures are known to be responsible for heterogeneous chlorine activation that leads to polar ozone depletion. Here, we discuss the temperature threshold below which substantial chlorine activation occurs. We suggest that the onset of chlorine activation is dominated by reactions on cold binary aerosol particles, without the formation of polar stratospheric clouds (PSCs), i.e. without any significant uptake of HNO3 from the gas phase. Using reaction rates on cold binary aerosol in a model of stratospheric chemistry, a chlorine activation threshold temperature, TACL, is derived. At typical stratospheric conditions, TACL is similar in value to TNAT (within 1-2 K), the highest temperature at which nitric acid trihydrate (NAT) can exist. TNAT is still in use to parameterise the threshold temperature for the onset of chlorine activation. However, perturbations can cause TACL to differ from TNAT: TACL is dependent upon H2O and potential temperature, but unlike TNAT is not dependent upon HNO3. Furthermore, in contrast to TNAT, TACL is dependent upon the stratospheric sulfate aerosol loading and thus provides a means to estimate the impact on polar ozone of strong volcanic eruptions and some geo-engineering options, which are discussed. A parameterisation of TACL is provided here, allowing it to be calculated for low solar elevation (or high solar zenith angle) over a comprehensive range of stratospheric conditions. Considering TACL as a proxy for chlorine activation cannot replace a detailed model calculation, and polar ozone loss is influenced by other factors apart from the initial chlorine activation. However, TACL provides a more accurate description of the temperature conditions necessary for chlorine activation and ozone loss in the polar stratosphere than TNAT.

  10. Kelvin wave variability in the upper stratosphere observed in SBUV ozone data. [SBUV (solar backscatter ultraviolet)

    SciTech Connect

    Randel, W.J.; Gille, J.C. )

    1991-11-01

    The signatures of equatorially trapped Kelvin waves in the upper stratosphere are analyzed in Solar Backscatter Ultraviolet (SBUV) ozone data over the years 1979-86. Comparisons are first made with contemporaneous Limb Infrared Monitor of the Stratosphere (LIMS) ozone data to validate the SBUV Kelvin wave signatures. SBUV and LIMS data both show coherent Kelvin wave oscillations in the upper stratosphere, where ozone is photochemically controlled, and mirrors the temperature fluctuations associated with Kelvin waves; however, SBUV data underestimate wave amplitudes by 20%-60%. Furthermore, transport-induced Kelvin wave patterns in the lower stratosphere are not observed in SBUV data. The eight years of SBUV data reveal the regular occurrence of eastward-propagating zonal wave 1-2 Kelvin waves with periods in the range of 5-15 days. These data show a strong semiannual modulation of Kelvin wave activity, as documented previously in rocketsonde observations. Eight-year-average ensemble spectra are compared to the semiannual oscillation (SAO) in stratospheric zonal winds; a seasonal asymmetry in the strength of Kelvin waves is found, which mimics that observed in the zonal winds. There is a near exact phasing of maxima in wave variance with the strongest easterly zonal winds, i.e., when the wind acceleration is near zero; this argues that Kelvin waves are not a determining factor in the westerly acceleration phase. An exception is found near the stratopause in January when Kelvin wave maxima coincide with strong westerly acceleration. Interannual variability of Kelvin waves is studied in relation to that of the stratospheric zonal winds. No consistent relationship with the quasi-biennial oscillation (QBO) in the lower stratosphere is observed, and correlations with upper stratospheric winds are weak or nonexistent. 35 refs., 11 figs., 1 tab.

  11. Asymmetries in ozone depressions between the polar stratospheres following a solar proton event

    NASA Technical Reports Server (NTRS)

    Maeda, K.; Heath, D. F.

    1978-01-01

    Ozone depletions in the polar stratosphere during the energetic solar proton event on 4 August 1972 were observed by the backscattered ultraviolet (BUV) experiments on the Nimbus 4 satellite. The observed ozone contents, the ozone depressions and their temporal variations above the 4 mb level exhibited distinct asymmetries between the northern and southern hemispheres. Since the ozone destroying solar particles precipitate rather symmetrically into the two polar atmospheres, due to the geomagnetic dipole field, it is suggested that these asymmetries may be explained in terms of the differences in dynamics between the summer and the winter polar atmospheres. In the summer (northern) hemisphere, the stratospheric and mesospheric ozone depletion and recovery are smooth functions of time due to the preponderance of undistributed orderly flow in this region. On the other hand, the temporal variation of the upper stratospheric ozone in the winter polar atmosphere (southern hemisphere) exhibits large amplitude irregularities. These characteristic differences between the two polar atmospheres are also evident in the vertical distributions of temperatures and winds observed by balloons and rocket soundings.

  12. Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

    NASA Astrophysics Data System (ADS)

    Nowack, Peer Johannes; Abraham, Nathan Luke; Braesicke, Peter; Pyle, John Adrian

    2016-03-01

    Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere-ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

  13. Comment on "Enhanced upper stratospheric ozone: Sign of recovery or solar cycle effect?"

    NASA Technical Reports Server (NTRS)

    Cunnold, D. M.; Yang, E.-S.; Newchurch, M. J.; Reinsel, G. C.; Zawodny, J. M.; Russell, J. M., III

    2004-01-01

    [01] Steinbrecht et al. [2004] (hereinafter referred to as S4) have discussed the trend in upper stratospheric ozone at 35 -45-km altitude determined from their lidar measurements at Hohenpeissenberg (47.8degN, 11.0degE) from 1987 to 2003. They question the conclusion of Newchurch et al. [2003] (hereinafter referred to as N3) that after approximately 1997 the downward trend of upper stratospheric ozone at 35-45-km altitude has diminished significantly. They argue instead that recent ozone changes are associated with the recent solar maximum (i.e., the solar cycle effect on ozone). In this comment we question their procedure for identifying the solar cycle effect. Moreover, we argue that the solar cycle effect was appropriately accounted for in the N3 analysis, and we buttress our argument by demonstrating that the more extensive data set used by N3 shows that the trend in upper stratospheric ozone has diminished significantly since 1997 and that this is evidence of the first stage of ozone recovery.

  14. Climate change and atmospheric chemistry: how will the stratospheric ozone layer develop?

    PubMed

    Dameris, Martin

    2010-10-25

    The discovery of the ozone hole over Antarctica in 1985 was a surprise for science. For a few years the reasons of the ozone hole was speculated about. Soon it was obvious that predominant meteorological conditions led to a specific situation developing in this part of the atmosphere: Very low temperatures initiate chemical processes that at the end cause extreme ozone depletion at altitudes of between about 15 and 30 km. So-called polar stratospheric clouds play a key role. Such clouds develop at temperatures below about 195 K. Heterogeneous chemical reactions on cloud particles initiate the destruction of ozone molecules. The future evolution of the ozone layer will not only depend on the further development of concentrations of ozone-depleting substances, but also significantly on climate change.

  15. Climate change and atmospheric chemistry: how will the stratospheric ozone layer develop?

    PubMed

    Dameris, Martin

    2010-10-25

    The discovery of the ozone hole over Antarctica in 1985 was a surprise for science. For a few years the reasons of the ozone hole was speculated about. Soon it was obvious that predominant meteorological conditions led to a specific situation developing in this part of the atmosphere: Very low temperatures initiate chemical processes that at the end cause extreme ozone depletion at altitudes of between about 15 and 30 km. So-called polar stratospheric clouds play a key role. Such clouds develop at temperatures below about 195 K. Heterogeneous chemical reactions on cloud particles initiate the destruction of ozone molecules. The future evolution of the ozone layer will not only depend on the further development of concentrations of ozone-depleting substances, but also significantly on climate change. PMID:20922727

  16. The evolution of the ozone collar in the Antarctic lower stratosphere during early August 1994

    SciTech Connect

    Mariotti, A.; Mechoso, C.R.; Legras, B.; Daniel, V.

    2000-02-01

    The ozone evolution in the lower stratosphere of the Southern Hemisphere during the period 5--10 August 1994 is analyzed. The analysis focuses on the ozone collar (the band of maximum values in ozone mixing ratio around the Antarctic ozone hole at these altitudes) and the development of collar filaments. Ozone mixing ratios provided by the Microwave Limb Sounder (MLS) on board the Upper Atmosphere Research Satellite and by an ER-2 aircraft participating in the Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of stratospheric Aircraft campaign are compared with values at corresponding locations in high-resolution isentropic maps obtained by using the numerical scheme of contour advection with surgery (CAS). The CAS reconstructed ozone maps provide a view of the way in which air masses are exported from the outskirts of the collar to form the tongues of higher mixing ratios observed at lower latitudes on MLS synoptic maps. There is an overall consistency between the datasets insofar as the collar location is concerned. This location seems to be primarily defined by the local properties of the flow. Nevertheless the CAS reconstructed collar tends to become weaker than that depicted by MLS data. By means of radioactive calculation estimates, it is argued that diabatic descent may be responsible for maintaining the ozone concentration approximately constant in the collar while filaments isentropically disperse collarlike mixing ratios from this region toward lower latitudes.

  17. Transport versus energetic particle precipitation: Northern polar stratospheric NOx and ozone in January-March 2012

    NASA Astrophysics Data System (ADS)

    Päivärinta, S.-M.; Verronen, P. T.; Funke, B.; Gardini, A.; Seppälä, A.; Andersson, M. E.

    2016-05-01

    In early 2012, a strong sudden stratospheric warming (SSW) took place, accompanied by several medium-scale solar proton events (SPEs). Here we use a chemistry transport model (CTM) in order to assess the relative contributions of (1) intensified downward transport of odd nitrogen (NOx) and (2) in situ production of NOx by protons, on stratospheric NOx and ozone during January-March 2012. The CTM is constrained by an upper boundary condition for reactive nitrogen (NOy) species, based on satellite observations from Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board Envisat, and includes a new parameterization of the SPE-caused effects on NOy and odd hydrogen (HOx) species. We found that the amount of NOx increases due to both transport and in situ production effects, the intensified descent of NOx dominating the middle and upper stratospheric impact. The model results indicate NOx enhancements of 120-3300% (5-48 ppbv) between 38 and 50 km, caused by the transport of mesosphere/lower thermosphere NOx down to the stratosphere following the SSW. The SPEs increase NOx by up to 820-1200% (14-21 ppbv) at 33 to 50 km. The effect on the stratospheric ozone is larger following the downward transport of NOx than during and after the SPEs. The model predicts ozone losses of up to 17% and 9% at around 40 km due to transport and SPE effects, respectively.

  18. Stratospheric ClO and ozone from the Microwave Limb Sounder on the Upper Atmosphere Research Satellite

    NASA Technical Reports Server (NTRS)

    Waters, J. W.; Froidevaux, L.; Read, W. G.; Manney, G. L.; Elson, L. S.; Flower, D. A.; Jarnot, R. F.; Harwood, R. S.

    1993-01-01

    Concentrations of atmospheric ozone and of ClO (the predominant form of reactive chlorine responsible for stratospheric ozone depletion) are reported for both the Arctic and Antarctic winters of the past 18 months. Chlorine in the lower stratosphere was almost completely converted to chemically reactive forms in both the northern and southern polar winter vortices. This occurred in the south long before the development of the Antarctic ozone hole, suggesting that ozone loss can be masked by influx of ozone-rich air.

  19. 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.

  20. Identifying and forecasting deep stratospheric ozone intrusions over the western United States from space

    NASA Astrophysics Data System (ADS)

    Lin, M.; Fiore, A. M.; Horowitz, L. W.; Cooper, O. R.; Langford, A. O.; Pan, L.; Liu, X.; Reddy, P. J.

    2012-12-01

    Recent studies have shown that deep stratospheric ozone intrusions can episodically enhance ground-level ozone above the health-based standard over the western U.S. in spring. Advanced warning of incoming intrusions could be used by state agencies to inform the public about poor air quality days. Here we explore the potential for using total ozone retrievals (version 5.2, level 3) at twice daily near global coverage from the AIRS instrument aboard the NASA Aqua satellite to identify stratospheric intrusions and forecast the eventual surface destination of transported stratospheric ozone. The method involves the correlation of AIRS daily total ozone columns at each 1ox1o grid box ~1-3 days prior to stratospheric enhancements to daily maximum 8-hour average ozone at a selected surface site using datasets from April to June in 2003-2011. The surface stratospheric enhancements are estimated by the GFDL AM3 chemistry-climate model which includes full stratospheric and tropospheric chemistry and is nudged to reanalysis winds. Our earlier work shows that the model presents deep stratospheric intrusions over the Western U.S. consistently with observations from AIRS, surface networks, daily ozone sondes, and aircraft lidar available in spring of 2010 during the NOAA CalNex field campaign. For the 15 surface sites in the U.S. Mountain West considered, a correlation coefficient of 0.4-0.7 emerges with AIRS ozone columns over 30o-50oN latitudes and 125o-105oW longitudes - variability in the AIRS column within this spatial domain indicates incoming intrusions. For each "surface receptor site", the spatial domain can narrow to an area ~5ox5o northwest of the individual site, with the strong correlation (0.5-0.7) occurring when the AIRS data is lagged by 1 day from the AM3 stratospheric enhancements in surface air. The spatial pattern of correlations is consistent with our process-oriented understanding developed from case studies of extreme intrusions. Surface observations

  1. 75 FR 41177 - Protection of Stratospheric Ozone: Request for Methyl Bromide Critical Use Exemption Applications...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-15

    ... extent, and by means of the procedures, set forth under 40 CFR part 2 subpart B; 41 FR 36752, 43 FR 40000, 50 FR 51661. If no claim of confidentiality accompanies the information when EPA receives it, EPA may... AGENCY Protection of Stratospheric Ozone: Request for Methyl Bromide Critical Use Exemption...

  2. 75 FR 34017 - Protection of Stratospheric Ozone: Notice 25 for Significant New Alternatives Policy Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-16

    ... AGENCY 40 CFR Part 82 RIN 2060-AG12 Protection of Stratospheric Ozone: Notice 25 for Significant New... rulemaking published in the Federal Register on March 18, 1994 (59 FR 13044). Notices and rulemakings under... implementing Section 612? On March 18, 1994, EPA published the original rule (59 FR 13044) establishing...

  3. Lidar measurements of stratospheric ozone at Table Mountain, California, since 1988

    NASA Technical Reports Server (NTRS)

    Mcdermid, I. Stuart; Schmoe, Martha; Walsh, T. Daniel

    1994-01-01

    Regular measurements of stratospheric ozone concentration profiles have been made at Table Mountain, California, since January 1988. During the period to December 1991, 435 independent profiles were measured by the differential absorption lidar technique. These long-term results, and an evaluation of their quality, is presented in this paper.

  4. An investigation of the processes controlling ozone in the upper stratosphere

    NASA Technical Reports Server (NTRS)

    Patten, Kenneth O., Jr.; Connell, Peter S.; Kinnison, Douglas E.; Wuebbles, Donald J.; Waters, Joe; Froidevaux, Lucien; Slanger, Tom G.

    1994-01-01

    Photolysis of vibrationally excited oxygen produced by ultraviolet photolysis of ozone in the upper stratosphere is incorporated into the Lawrence Livermore National Laboratory 2-D zonally averaged chemical-radiative-transport model of the troposphere and stratosphere. The importance of this potential contributor of odd oxygen to the concentration of ozone is evaluated based upon recent information on vibrational distributions of excited oxygen and upon preliminary studies of energy transfer from the excited oxygen. When the energy transfer rate constants of previous work are assumed, increases in model ozone concentrations of up to 40 percent in the upper stratosphere are found, and the ozone concentrations of the model agree with measurements, including data from the Upper Atmosphere Research Satellite. However, the increase is about 0.4 percent when the larger energy transfer rate constants suggested by more recent experimental work are applied in the model. This indicates the importance of obtaining detailed information on vibrationally excited oxygen properties to evaluation of this process for stratospheric modelling.

  5. 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.

  6. Laboratory studies of chemical and photochemical processes relevant to stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Zahniser, Mark S.; Nelson, David D.; Worsnop, Douglas R.; Kolb, Charles E.

    1994-01-01

    The purpose of this project is to reduce the uncertainty in several key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring rate coefficients and product channels for reactions of HO(sub x) and NO(sub x) species in the temperature range 200 K to 240 K relevant to the lower stratosphere. Other areas of study have included infrared spectroscopic studies of the HO2 radical, measurements of OH radical reactions with alternative fluorocarbons, and determination of the vapor pressures of nitric acid hydrates under stratospheric conditions. The results of these studies will improve models of stratospheric ozone chemistry and predictions of perturbations due to human influences. In this annual report, we focus on our recent accomplishments in the quantitative spectroscopy of the HO2 radical. This report details the measurements of the broadening coefficients for the v(sub 2) vibrational band. Further measurements of the vapor pressures of nitric acid hydrates relevant to the polar stratospheric cloud formation indicate the importance of metastable crystalline phases of H2SO4, HNO3, and H2O. Large particles produced from these metastable phases may provide a removal mechanism for HNO3 in the polar stratosphere.

  7. The natural oscillations in stratospheric ozone observed by the GROMOS microwave radiometer at the NDACC station Bern

    NASA Astrophysics Data System (ADS)

    Moreira, Lorena; Hocke, Klemens; Navas-Guzmán, Francisco; Eckert, Ellen; von Clarmann, Thomas; Kämpfer, Niklaus

    2016-08-01

    A multilinear parametric regression analysis was performed to assess the seasonal and interannual variations of stratospheric ozone profiles from the GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) microwave radiometer at Bern, Switzerland (46.95° N, 7.44° E; 577 m). GROMOS takes part in the Network for the Detection of Atmospheric Composition Change (NDACC). The study covers the stratosphere from 50 to 0.5 hPa (from 21 to 53 km) and extends over the period from January 1997 to January 2015. The natural variability was fitted during the regression analysis through the annual and semi-annual oscillations (AO, SAO), the quasi-biennial oscillation (QBO), the El Niño-Southern Oscillation (ENSO) and the solar activity cycle. Seasonal ozone variations mainly appear as an annual cycle in the middle and upper stratosphere and a semi-annual cycle in the upper stratosphere. Regarding the interannual variations, they are primarily present in the lower and middle stratosphere. In the lower and middle stratosphere, ozone variations are controlled predominantly by transport processes, due to the long lifetime of ozone, whereas in the upper stratosphere its lifetime is relatively short and ozone is controlled mainly by photochemistry. The present study shows agreement in the observed naturally induced ozone signatures with other studies. Further, we present an overview of the possible causes of the effects observed in stratospheric ozone due to natural oscillations at a northern midlatitude station. For instance regarding the SAO, we find that polar winter stratopause warmings contribute to the strength of this oscillation since these temperature enhancements lead to a reduction in upper stratospheric ozone. We have detected a strong peak amplitude of about 5 % for the solar cycle in lower stratospheric ozone for our 1.5 cycles of solar activity. Though the 11-year ozone oscillation above Bern is in phase with the solar cycle, we suppose that the strong amplitude is

  8. Global Observations Of Stratospheric Heavy Ozone Isotopologue Enrichment With The Odin Sub-Millimetre Radiometer

    NASA Astrophysics Data System (ADS)

    Urban, J.; Murtagh, D. P.; Kasai, Y.; Jones, A.; Walker, K. A.

    2013-12-01

    The Odin Sub-Millimetre Radiometer (SMR) measures thermal emission lines of several minor ozone isotopo- logues such as symmetric and asymmetric O3-18 and asymmetric O3-17 at the atmospheric limb. The global data set spans over 11 years starting in late 2001. The basic characteristics and limitations of the observational data are presented and the global distribution of heavy ozone isotopologue enrichment as seen by Odin is described and discussed. Best results in terms of spatial coverage are obtained for asymmetric O3-18, which shows a characteristic increase of the enrichment in the middle to upper stratosphere and the smallest enrichment in the polar lower stratosphere. Symmetric O3-18 is characterised by a layer of maximum enrichment in the middle stratosphere.

  9. Ozone and aerosol changes during the 1991-1992 airborne arctic stratospheric expedition.

    PubMed

    Browell, E V; Butler, C F; Fenn, M A; Grant, W B; Ismail, S; Schoeberl, M R; Toon, O B; Loewenstein, M; Podolske, J R

    1993-08-27

    Stratospheric ozone and aerosol distributions were measured across the wintertime Arctic vortex from January to March 1992 with an airborne lidar system as part of the 1992 Airborne Arctic Stratospheric Expedition (AASE II). Aerosols from the Mount Pinatubo eruption were found outside and inside the vortex with distinctly different distributions that clearly identified the dynamics of the vortex. Changes in aerosols inside the vortex indicated advection of air from outside to inside the vortex below 16 kilometers. No polar stratospheric clouds were observed and no evidence was found for frozen volcanic aerosols inside the vortex. Between January and March, ozone depletion was observed inside the vortex from 14 to 20 kilometers with a maximum average loss of about 23 percent near 18 kilometers.

  10. Strong modification of stratospheric ozone forcing by cloud and sea-ice adjustments

    NASA Astrophysics Data System (ADS)

    Xia, Yan; Hu, Yongyun; Huang, Yi

    2016-06-01

    We investigate the climatic impact of stratospheric ozone recovery (SOR), with a focus on the surface temperature change in atmosphere-slab ocean coupled climate simulations. We find that although SOR would cause significant surface warming (global mean: 0.2 K) in a climate free of clouds and sea ice, it causes surface cooling (-0.06 K) in the real climate. The results here are especially interesting in that the stratosphere-adjusted radiative forcing is positive in both cases. Radiation diagnosis shows that the surface cooling is mainly due to a strong radiative effect resulting from significant reduction of global high clouds and, to a lesser extent, from an increase in high-latitude sea ice. Our simulation experiments suggest that clouds and sea ice are sensitive to stratospheric ozone perturbation, which constitutes a significant radiative adjustment that influences the sign and magnitude of the global surface temperature change.

  11. Laboratory Studies of Chemical and Photochemical Processes Relevant to Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Villalta, Peter W.; Zahniser, Mark S.; Nelson, David D.; Kolb, Charles E.

    1997-01-01

    The purpose of this project is to reduce the uncertainty in several key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring rate coefficients and product channels for reactions of HO(x) and NO(x) species in the temperature range 200 K to 240 K relevant to the lower stratosphere. The results of these studies will improve models of stratospheric ozone chemistry and predictions of perturbations due to human influences. The second year's effort has focussed the design and construction of the proposed high pressure flow reactor on three separate areas: (1) the construction of the high pressure flow reactor; (2) characterization of the turbulent flow profile; and (3) demonstration of the instrument by measuring HO2 + NO2 and HO2 + NO reaction rate coefficients.

  12. The influence of climate change and the timing of stratospheric warmings on Arctic ozone depletion

    SciTech Connect

    Austin, J.; Butchart, N.

    1994-01-20

    A three-dimensional model is presented to evaluate the influence of climatic change and increased carbon dioxide concentrations on ozone depletion in the Arctic region. Satellite data showing the time of stratospheric warmings during the winters of 1979-1992 is used in a series of idealized experiments where the timing of the warmings is varied by using different geopotential wave amplitudes. Results of the experiments indicate that for doubled atmospheric carbon dioxide levels, an ozone hole in the Arctic is more likely to develop during years where late stratospheric warming has occurred after a relatively quiescent winter. The validity of this model is dependent on the future composition and temperature of the stratosphere. 43 refs., 21 figs.

  13. Quantifying Stratospheric Ozone in the Upper Troposphere Using in situ Measurements of HCl

    SciTech Connect

    Atherton, C S; Bergmann, D J; Marcy, T P; Fahey, D W; Gao, R S; Popp, P J; Richard, E C; Thompson, T L; Rosenlof, K H; Ray, E A; Salawitch, R J; Ridley, B A; . Weinheimer, A J; Loewenstein, M; Weinstock, E M; Mahoney, M J

    2004-03-08

    A chemical ionization mass spectrometry (CIMS) technique has been developed for precise in situ measurements of hydrochloric acid (HCl) from a high-altitude aircraft. In measurements at subtropical latitudes, minimum HCl values found in the upper troposphere (UT) are often near or below the 0.005-ppbv detection limit of the measurements, indicating that background HCl values are much lower than a global mean estimate. However, significant abundances of HCl were observed in many UT air parcels as a result of stratosphere-to-troposphere transport events. A method for diagnosing the amount of stratospheric ozone in these UT parcels was developed using the compact linear correlation of HCl with ozone found throughout the lower stratosphere (LS). Expanded use of this method will lead to improved quantification of cross-tropopause transport events and validation of global chemical transport models.

  14. Raman DIAL measurements of stratospheric ozone in the presence of volcanic aerosols

    NASA Technical Reports Server (NTRS)

    Mcgee, Thomas J.; Gross, Michael; Ferrare, Richard; Heaps, William; Singh, Upendra

    1993-01-01

    Since the eruption of Mt. Pinatubo in June, 1991, measurements of atmospheric species which depend on Rayleigh scattering of radiation, have been severely compromised where the volcanic aerosol cloud exists. For the GSFC stratospheric ozone lidar, this has meant that ozone determination has been impossible below approximately 30 km. The GSFC lidar has been modified to detect Raman scattering from nitrogen molecules from transmitted laser wavelengths. The instrument transmits two laser wavelengths at 308 nm and 351 nm, and detects returns at four wavelengths; 308 nm, 332 nm, 351 nm, and 382 nm. Using this technique in conjunction with the Rayleigh DIAL measurement, ozone profiles have been measured between 15 and 50 km.

  15. Statistical analysis of stratospheric temperature and ozone profile data for trends and model comparison

    NASA Technical Reports Server (NTRS)

    Tiao, G. C.

    1992-01-01

    Work performed during the project period July 1, 1990 to June 30, 1992 on the statistical analysis of stratospheric temperature data, rawinsonde temperature data, and ozone profile data for the detection of trends is described. Our principal topics of research are trend analysis of NOAA stratospheric temperature data over the period 1978-1989; trend analysis of rawinsonde temperature data for the period 1964-1988; trend analysis of Umkehr ozone profile data for the period 1977-1991; and comparison of observed ozone and temperature trends in the lower stratosphere. Analysis of NOAA stratospheric temperature data indicates the existence of large negative trends at 0.4 mb level, with magnitudes increasing with latitudes away from the equator. Trend analysis of rawinsonde temperature data over 184 stations shows significant positive trends about 0.2 C per decade at surface to 500 mb range, decreasing to negative trends about -0.3 C at 100 to 50 mb range, and increasing slightly at 30 mb level. There is little evidence of seasonal variation in trends. Analysis of Umkehr ozone data for 12 northern hemispheric stations shows significant negative trends about -.5 percent per year in Umkehr layers 7-9 and layer 3, but somewhat less negative trends in layers 4-6. There is no pronounced seasonal variation in trends, especially in layers 4-9. A comparison was made of empirical temperature trends from rawinsonde data in the lower stratosphere with temperature changes determined from a one-dimensional radiative transfer calculation that prescribed a given ozone change over the altitude region, surface to 50 km, obtained from trend analysis of ozonsonde and Umkehr profile data. The empirical and calculated temperature trends are found in substantive agreement in profile shape and magnitude.

  16. In situ stratospheric ozone measurements by long path UV absorption - Developments and interpretation

    NASA Technical Reports Server (NTRS)

    Weinstock, E. M.; Schiller, C. M.; Anderson, J. G.

    1986-01-01

    A high-sensitivity, in situ UV absorption ozone sensor has been developed for use in the stratosphere. The instrument couples 254-nm radiation from a low-pressure mercury discharge lamp into a 40-pass White cell to attain a high-sensitivity ozone absorption measurement. Preflight/postflight laboratory tests utilizing an ozone source coupled to a laboratory UV ozone photometer in a fast-flow system as well as in-flight diagnostics verify the successful operation of the instrument. Evidence is presented to verify that in situ UV absorption ozone photometers can measure stratospheric ozone with better than 3 percent precision and 5 percent accuracy, provided proper attention is given to both the thermal field surrounding the gondola and the ambient pressure measurements. Ozone data are compared with modeled profiles in the 28- to 40-km region. An assessment of the disagreement between observations and modeled profiles is given along with suggestions for future experiments designed to constrain photochemical models.

  17. Copernicus stratospheric ozone service, 2009-2012: validation, system intercomparison and roles of input data sets

    NASA Astrophysics Data System (ADS)

    Lefever, K.; van der A, R.; Baier, F.; Christophe, Y.; Errera, Q.; Eskes, H.; Flemming, J.; Inness, A.; Jones, L.; Lambert, J.-C.; Langerock, B.; Schultz, M. G.; Stein, O.; Wagner, A.; Chabrillat, S.

    2015-03-01

    This paper evaluates and discusses the quality of the stratospheric ozone analyses delivered in near real time by the MACC (Monitoring Atmospheric Composition and Climate) project during the 3-year period between September 2009 and September 2012. Ozone analyses produced by four different chemical data assimilation (CDA) systems are examined and compared: the Integrated Forecast System coupled to the Model for OZone And Related chemical Tracers (IFS-MOZART); the Belgian Assimilation System for Chemical ObsErvations (BASCOE); the Synoptic Analysis of Chemical Constituents by Advanced Data Assimilation (SACADA); and the Data Assimilation Model based on Transport Model version 3 (TM3DAM). The assimilated satellite ozone retrievals differed for each system; SACADA and TM3DAM assimilated only total ozone observations, BASCOE assimilated profiles for ozone and some related species, while IFS-MOZART assimilated both types of ozone observations. All analyses deliver total column values that agree well with ground-based observations (biases < 5%) and have a realistic seasonal cycle, except for BASCOE analyses, which underestimate total ozone in the tropics all year long by 7 to 10%, and SACADA analyses, which overestimate total ozone in polar night regions by up to 30%. The validation of the vertical distribution is based on independent observations from ozonesondes and the ACE-FTS (Atmospheric Chemistry Experiment - Fourier Transform Spectrometer) satellite instrument. It cannot be performed with TM3DAM, which is designed only to deliver analyses of total ozone columns. Vertically alternating positive and negative biases are found in the IFS-MOZART analyses as well as an overestimation of 30 to 60% in the polar lower stratosphere during polar ozone depletion events. SACADA underestimates lower stratospheric ozone by up to 50% during these events above the South Pole and overestimates it by approximately the same amount in the tropics. The three-dimensional (3-D) analyses

  18. 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.

  19. Recent trends in ozone in the upper stratosphere: Implications for chlorine chemistry

    SciTech Connect

    Chandra, S.; Jackman, C.H.; Fleming, E.L.

    1995-04-01

    The authors have studied the implications of recent trends in the annual mean and the amplitude of the annual harmonic of ozone in the upper stratosphere from the 15 years of the combined data from the Nimbus-7 SBUV and the NOAA-11 SBUV/2 instruments. This was done in the context of the GSFC 2D model predictions of these trends which are based on plausible scenarios of anthropogenic Cl{sub y} increase in the atmosphere. The comparison of the observed and model-estimated annual mean ozone trends show some similarity in their latitude and altitude characteristics. Both the model and data show a maximum ozone decrease of {minus}6 to {minus}10% per decade at high latitudes in the upper stratosphere. However, there are also significant differences between the observed and computed trends which may be related to both the model uncertainty and the uncertainty in correcting for the long term instrument drift. The observations also suggest a decrease of 10-25% per decade in the annual amplitude of ozone at 2 mb between 40{degrees}-60{degrees} in both hemispheres, with a relatively larger interannual variability in the northern hemisphere. These values are in general agreement with the model predictions and thus provide additional support in favor of the chlorine induced changes in ozone in the upper stratosphere. 13 refs., 3 figs.

  20. 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.

  1. Recent trends in ozone in the upper stratosphere: Implications for chlorine chemistry

    NASA Technical Reports Server (NTRS)

    Chandra, Sushil; Jackman, Charles H.; Fleming, Eric L.

    1995-01-01

    We have studied the implications of recent trends in the annual mean and the amplitude of the annual harmonic of ozone in the upper stratosphere from the 15 years of the combined data from the Nimbus-7 SBUV and the NOAA-11 SBUV/2 instruments. This was done in the context of the GSFC 2D model predictions of these trends which are based on plausible scenarios of anthropogenic Cly increase in the atmosphere. The comparison of the observed and model-estimated annual mean ozone trends show some similarity in their latitude and altitude characteristics. Both the model and data show a maximum ozone decrease of -6 to -10 % per decade at high latitudes in the upper stratosphere. However, there are also significant differences between the observed and computed trends which may be related to both the model uncertainty and the uncertainty in correcting for the long term instrument drift. The observations also suggest a decrease of 10-25 % per decade in the annual amplitude of ozone at 2 mb between 40 deg - 60 deg in both hemispheres, with a relatively larger interannual variability in the northern hemisphere. These values are in general agreement with the model predictions and thus provide additional support in favor of the chlorine induced changes in ozone in the upper stratosphere.

  2. Stratospheric ozone response to a solar irradiance reduction in a quadrupled CO2 environment

    NASA Astrophysics Data System (ADS)

    Jackman, Charles H.; Fleming, Eric L.

    2014-07-01

    We used the Goddard Space Flight Center (GSFC) global two-dimensional (2D) atmospheric model to investigate the stratospheric ozone response to a proposed geoengineering activity wherein a reduced top-of-atmosphere (TOA) solar irradiance is imposed to help counteract a quadrupled CO2 atmosphere. This study is similar to the Geoengineering Model Intercomparison Project (GeoMIP) Experiment G1. Three primary simulations were completed with the GSFC 2D model to examine this possibility: (A) a pre-industrial atmosphere with a boundary condition of 285 ppmv CO2 (piControl); (B) a base future atmosphere with 1140 ppmv CO2 (abrupt4xCO2); and (C) a perturbed future atmosphere with 1140 ppmv CO2 and a 4% reduction in the TOA total solar irradiance (G1). We found huge ozone enhancements throughout most of the stratosphere (up to 40%) as a result of a large computed temperature decrease (up to 18 K) when CO2 was quadrupled (compare simulation abrupt4xCO2 to piControl). Further, we found that ozone will additionally increase (up to 5%) throughout most of the stratosphere with total ozone increases of 1-2.5% as a result of a reduction in TOA total solar irradiance (compare simulation G1 to abrupt4xCO2). Decreases of atomic oxygen and temperature are the main drivers of this computed ozone enhancement from a reduction in TOA total solar irradiance.

  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. Ozone: Does It Affect Me?

    ERIC Educational Resources Information Center

    Wilson, Karla G.

    This curriculum unit on the ozone is intended for high school students and contains sections on environmental science and chemistry. It has been structured according to a learning cycle model and contains numerous activities, some of which are in a cooperative learning format. Skills emphasized include laboratory procedures, experimental design,…

  5. Intercomparison of stratospheric ozone profiles for the assessment of the upgraded GROMOS radiometer at Bern

    NASA Astrophysics Data System (ADS)

    Studer, S.; Hocke, K.; Pastel, M.; Godin-Beekmann, S.; Kämpfer, N.

    2013-07-01

    Since November 1994, the GROund-based Millimeter-wave Ozone Spectrometer (GROMOS) measures stratospheric and lower mesospheric ozone in Bern, Switzerland (47.95° N, 7.44° E). GROMOS is part of the Network for the Detection of Atmospheric Composition Change (NDACC). In July 2009, a Fast-Fourier-Transform spectrometer (FFTS) has been added as backend to GROMOS. The new FFTS and the original filter bench (FB) measured parallel for over two years. In October 2011, the FB has been turned off and the FFTS is now used to continue the ozone time series. For a consolidated ozone time series in the frame of NDACC, the quality of the stratospheric ozone profiles obtained with the FFTS has to be assessed. The FFTS results from July 2009 to December 2011 are compared to ozone profiles retrieved by the FB. FFTS and FB of the GROMOS microwave radiometer agree within 5% above 20 hPa. A later harmonization of both time series will be realized by taking the FFTS as benchmark for the FB. Ozone profiles from the FFTS are also compared to coinciding lidar measurements from the Observatoire Haute Provence (OHP), France. For the time period studied a maximum mean difference (lidar - GROMOS FFTS) of +3.8% at 3.1 hPa and a minimum mean difference of +1.4% at 8 hPa is found. Further, intercomparisons with ozone profiles from other independent instruments are performed: satellite measurements include MIPAS onboard ENVISAT, SABER onboard TIMED, MLS onboard EOS Aura and ACE-FTS onboard SCISAT-1. Additionally, ozonesondes launched from Payerne, Switzerland, are used in the lower stratosphere. Mean relative differences of GROMOS FFTS and these independent instruments are less than 10% between 50 and 0.1 hPa.

  6. Measurement of ozone concentration in the lower stratosphere and upper troposhere

    NASA Astrophysics Data System (ADS)

    Nevzorov, A. A.; Burlakov, V. D.; Dolgii, S. I.; Nevzorov, A. V.; Romanovskii, O. A.; Gridnev, Yu. V.

    2015-11-01

    We describe an ozone lidar and consider an algorithm for retrieving the ozone concentration, taking into consideration the aerosol correction. Results of lidar measurements at wavelengths 299 and 341 nm well agree with model estimates, indicating that ozone is sensed with acceptable accuracies in the altitude range of about 6-18 km. It should be noted that the retrieved profiles of altitude distribution of ozone concentration more closely resemble those from satellite data than according to Krueger model. A lidar is developed and put into operation at Siberian Lidar Station (SLS) to measure the vertical ozone distribution (VOD) in the upper troposphere-lower stratosphere. Sensing is performed according to the method of differential absorption and scattering at wavelength pair 299/341 nm, which are respectively the first and second Stokes components of stimulated Raman scattering (SRS) conversion of the fourth harmonic of Nd:YAG laser (266 nm) in hydrogen.

  7. An assessment of the effect of supersonic aircraft operations on the stratospheric ozone content

    NASA Technical Reports Server (NTRS)

    Poppoff, I. G.; Whitten, R. C.; Turco, R. P.; Capone, L. A.

    1978-01-01

    An assessment of the potential effect on stratospheric ozone of an advanced supersonic transport operations is presented. This assessment, which was undertaken because of NASA's desire for an up-to-date evaluation to guide programs for the development of supersonic technology and improved aircraft engine designs, uses the most recent chemical reaction rate data. From the results of the present assessment it would appear that realistic fleet sizes should not cause concern with regard to the depletion of the total ozone overburden. For example, the NOx emission of one type designed to cruise at 20 km altitude will cause the ozone overburden to increase by 0.03% to 0.12%, depending upon which vertical transport is used. These ozone changes can be compared with the predictions of a 1.74% ozone decrease (for 100 Large SST's flying at 20 km) made in 1974 by the FAA's Climatic Impact Assessment Program.

  8. Southern Hemisphere climate trends skewed by coarse temporal resolution of specified stratospheric ozone

    NASA Astrophysics Data System (ADS)

    Neely, R. R., III; Marsh, D. R.; Smith, K. L.; Davis, S. M.; Polvani, L. M.

    2014-12-01

    Global climate models that do not include interactive middle atmosphere chemistry, such as those contributing to the Coupled Model Intercomparison Project Phase 5, typically specify stratospheric ozone using monthly-mean zonal-mean values. Here we show that such coarse temporal resolution leads to significant biases in the simulated climate of the Southern Hemisphere (SH) over the late twentieth century. This is demonstrated using the Whole Atmosphere Community Climate Model in simulations with and without interactive chemistry. Previous studies have attributed similar differences in SH climate change simulations to biases created by the spatial smoothing of specified ozone, i.e., due to prescribing zonal-mean concentrations. We isolate the impact of undersampling the rapid temporal changes in ozone during the seasonal evolution of the Antarctic ozone hole from the impact of prescribing zonal-means, and show that temporal resolution of prescribed ozone is of equal importance to zonal asymmetries.

  9. Biases in southern hemisphere climate trends induced by coarsely specifying the temporal resolution of stratospheric ozone

    NASA Astrophysics Data System (ADS)

    Neely, R. R.; Marsh, D. R.; Smith, K. L.; Davis, S. M.; Polvani, L. M.

    2014-12-01

    Global climate models that do not include interactive middle atmosphere chemistry, such as most of those contributing to the Coupled Model Intercomparison Project Phase 5, typically specify stratospheric ozone using monthly mean, zonal mean values and linearly interpolate to the time resolution of the model. We show that this method leads to significant biases in the simulated climate of the southern hemisphere (SH) over the late twentieth century. Previous studies have attributed similar biases in simulated SH climate change to the effect of the spatial smoothing of the specified ozone, i.e., to using zonal mean concentrations. We here show that the bias in climate trends due to undersampling of the rapid temporal changes in ozone during the seasonal evolution of the Antarctic ozone hole is considerable and reaches all the way into the troposphere. Our results suggest that the bias can be substantially reduced by specifying daily ozone concentrations.

  10. Ozone depletion in the arctic stratosphere in early 1993

    SciTech Connect

    Larsen, N.; Knudsen, B.; Mikkelsen, I.S.; Jorgensen, T.S.; Eriksen, P.

    1994-07-15

    The authors present the results of balloon-borne measurements of ozone densities over Greenland from the end of January 1993 thru March 1993. For the altitude range from 14 to 20 km they observed a substantial density decrease over this time period. The column integrated ozone density dropped by 12% in this time period.

  11. An Evaluation of the Quality of Halogen Occultation Experiment Ozone Profiles in the Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Bhatt, Praful P.; Remsberg, Ellis E.; Gordley, Larry L.; McInerney, Joseph M.; Brackett, Vince G.; Russell, James M., III

    1999-01-01

    The archived ozone profiles from the Halogen Occultation Experiment (HALOE) have already been corrected for the effects of the spectrally varying, interfering absorption due to aerosols composed of aqueous sulfuric acid, and agreement with correlative measurements in the stratosphere is generally excellent. However, comparisons of sets of coincident HALOE and ozonesonde profiles indicate occasional large differences at the lowest levels of the stratosphere. Most of those instances occur at altitudes just below a well-defined minimum in the 5.26 microns channel aerosol extinction profile, whose wavelength dependence is not represented by a sulfuric acid aerosol model. Further, when the aerosol extinction exceeds about 10(exp 3)/ km, the aerosol correction to the ozone channel transmittances is both large and uncertain. After screening out the HALOE ozone profile segments whose corresponding aerosol/cirrus corrections are likely uncertain and after averaging lie ozonesonde profiles into 2.5 km thick layers, we find that the HALOE ozone areas, on average, to within 10% of their coincident ozonesonde measurements down to 100 hPa at tropical/subtropical latitudes and to 200 hPa at extratropical latitudes. A tightening of the coincidence criteria for the comparisons does not improve the mean differences for the sets nearly as much. Part of the variance of the paired differences was also accounted for when the ozonesonde profile values were integrated into those 2.5 km layers, prior to taking differences. This improvement is due mainly to the vertical averaging of the local, higher-resolution ozonesonde data, matching the lower resolution for HALOE ozone in the lower stratosphere. It is concluded that HALOE is providing accurate ozone profiles throughout the lower stratosphere, when its correction for interfering aerosols has been well characterized and when cirrus layers are not indicated.

  12. Analysis of the vertically resolved ozone and temperature evolution in the lower and middle stratosphere

    NASA Astrophysics Data System (ADS)

    Brunner, Lukas; Steiner, Andrea Karin; Scherllin-Pirscher, Barbara; Kirchengast, Gottfried

    2014-05-01

    The stratospheric ozone layer transforms energy-rich UV radiation into heat and has therefore a strong impact on the temperature in this region. Ozone has been investigated closely since the detection of ozone loss through anthropogenic ozone-depleting substances. Recently the decrease of total ozone has slowed down or even reversed due to emission restrictions by the Montreal Protocol and follow-up agreements. Although a range of global, vertically resolved ozone measurements exist, most of them were not intended for long-term use. In order to receive reliable trends from these data careful inter-calibration and drift corrections need to be applied. We use ozone climatologies from the Solar Backscatter Ultraviolet (SBUV) instrument series, from the Global Ozone And Related trace gas Data records for the Stratosphere (GOZCARDS), and from four instruments presented in the HARMonized dataset of Ozone profiles (HARMOZ). For temperature we use a dataset provided by GPS radio occultation (RO). RO is a relatively new method with favorable properties like long-term stability, high vertical resolution, and no need for satellite inter-calibration. We use the recently reprocessed WEGC RO record, which includes measurements from the CHAMP, GRACE, and Formosat-3/COSMIC missions from 2001 to 2012. For comparison and for the analysis of longer time series of up to three decades we also look at radiosonde temperature data. Radiosondes also have high vertical resolution but sparse and irregular global coverage. Finally, we use re-analysis fields from the European Centre for Medium Range Weather Forecasts for both, ozone and temperature. We focus on the multi-dataset comparison of interannual variability and trends of ozone and temperature. The analysis is based on monthly zonal mean climatologies with a latitudinal resolution of 10 degrees. Interannual variability and trends are computed by applying a regression model to the de-seasonalized monthly climatologies, which includes

  13. Ozone Photolysis: Strong Isotopologue/isotopomer Selectivity in the Stratosphere

    NASA Astrophysics Data System (ADS)

    Gatti, Fabien; Ndengue, Steve; Jost, Remy; Halasz, Gabor; Vibok, Agnes

    2013-06-01

    Using the visible-UV absorption cross section (Abs. XS) of five ozone isotopologues and an averaged actinic flux, we have calculated the contribution of the atmospheric ozone photolysis to the oxygen isotope and ozone isotopologue/isotopomer enrichment. Five ozone isotopologues/isotopomers are considered among which three are symmetric, O^{16}3 (noted 666), O^{16}O^{17}O^{16} (676) and O^{16}O^{18}O^{16} (686), and two are asymmetric, O^{17}O^{16}_2 (667) and O^{18}O^{16}_2 (668). The photolysis rates of the five ozone isotopologues have been calculated as a function of altitude. The Multi Configuration Time Dependent Hartree (MCTDH) method and the potential energy surfaces calculates by R. Schinke and coworkers have been used. We have used experimental actinic fluxes, averaged for latitude and season, for altitudes varying by step of 4km up to 80km. Below 35km, the contribution of the Hartley band to the photolysis rates is restricted to its low energy range, named the Huggins band, which has strong isotopologue/isotopomer selectivity and then induces strong enrichment. Consequently, the isotopologue enrichment's due to ozone photolysis are strongly dependent of the altitude, with pronounced enrichment peaks around 35 km, the altitude corresponding to the maximum relative contribution of the Huggins band. We will also present some new simulations for the simulation of laser-induced quantum dynamics of the electronic and nuclear motion in the ozone molecule on the attosecond time scale.

  14. Invertability of ozone stratospheric column measurements by means of potential vorticity

    NASA Astrophysics Data System (ADS)

    Elbern, H.; Baier, F.

    2003-04-01

    Vertical ozone profile information for the stratosphere is not only necessary for chemistry transport models (CTMs) but today also regarded as beneficial for the radiative transport calculation in weather forecast models. However, mostly only column density data of ozone from satellite retrievals are readily available for assimilation in real time. Nevertheless, in large areas of the stratosphere correlations between ozone concentrations and potential vorticity (PV) exist, which can be exploited for profile estimates. In total the following sources of information at disposal in close real time: begin{enumerate} total ozone columns, potential vorticity for each geolocated GOME column, useful in the middle and lower stratosphere (except in a small latitude belt at the equator), and (potentially a priori information of CTM ozone column profile forecasts.) Detailed error covariances are established by 1996 SAGE profile retrievals obtained from DFD-DFD. Using these as system learning data in combination with given PV values, ROSE-CTM model profiles and inferred ozone columns, a statistical profile model can be developed. The retrieval model is a combination of stochastic models, based on the regression coefficients linking PV and ozone, and an algebraic model, exploiting the ozone column information. As statistical models, three approaches were tested: levelwise monovariate regression, levelwise multivariate regressions, and full Givens rotation. The mathematical procedure required is the general inversion of an ill-posed heteroscedatic problem. Depending on access to and quality of the ROSE-CTM model simulated ozone profiles, two different algorithms are pertinent: If the model simulations are not available or inferior to a recently available reference data set, a "optimal filtering" (or "stochastic inverse") algorithm is used. In contrast, for model simulations of useful quality, the Bayesian "Maximum A Posteriori" estimator (MAP) has been applied. Generally, the PV

  15. Comparisons of observed ozone trends in the stratosphere through examination of Umkehr and balloon ozonesonde data

    SciTech Connect

    Miller, A.J.; Nagatani, R.M.; Tiao, G.C.

    1995-06-20

    During the past several years, several authors have published results of the annual and seasonal trends depicted in the total ozone data from both satellite and ground-based observations. The examination of the vertical profile data available from the balloon ozonesonde and Umkehr observations, however, has been generally restricted to limited periods and to nonseasonal trend calculations. Within this study, the authors have examined the nonseasonal and the seasonal trend behavior of the ozone profile data from both ozonesonde and Umkehr measurements in a consistent manner, covering the same extended time period, 1968-1991, thus providing the first overall comparison of results. Their results reaffirm the observation of significant negative ozone trends in both the lower stratosphere (15-20 km), about {minus}6% per decade, and upper stratosphere (35-50 km), about {minus}6% per decade, separated by a nodal point in the region of 25-30 km. The upper stratosphere decrease is, apparently, associated with the classic gas phase chemical effect of the chlorofluorocarbons, whereas the cause of the lower stratospheric decline is still under investigation, but may well be associated with the chlorine and bromine chemistry in this region. 27 refs., 9 figs., 4 tabs.

  16. 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.

  17. Coherence of longterm stratospheric ozone time series for the study of ozone recovery in the northern mid-latitudes

    NASA Astrophysics Data System (ADS)

    Nair, Prijitha J.; Godin-Beekmann, Sophie; Pazmino, Andrea

    2010-05-01

    Since mid-to late 1980s decreasing amounts of ozone concentration has been observed in northern mid-latitudes mainly due to the ozone depleting chlorofluorocarbon loading in the stratosphere. Recent works indicate the stabilization of ozone loss in the mid-latitudes, in the upper stratosphere in particular. In order to further investigate the evolution of ozone in the mid-latitudes, a coherent dataset is required. As a first step, we diagnose the long term evolution of ozone at Observatoire de Haute Provence (OHP - 43.93°N, 5.71°E), one of the northern mid-latitude stations. In this study, we present the inter comparison of ozone measurements from OHP LIDAR with collocated SBUV, SAGEII, HALOE, MLS and GOMOS satellite observations as well as the ground based Ozonesondes and Umkehr measurements. A detailed statistical study on the relative differences of the compared measurements is performed to check any specific drifts with time. In addition, the seasonal and annual averages of the relative deviations are also checked to quantify agreement among the data. On average, all instruments show their best agreement with LIDAR between 20 and 40 km, where the differences are within 5%. The agreement with SAGEII measurements are remarkably good since it falls within 1% at 17-41 km. A similar result is also found from the Ozonesondes comparison at 22-31 km. Most comparisons exhibit slightly larger deviations below 20 and above 42 km, of about 10%. The LIDAR masurements are also compared to Umkehr measurements by converting its ozone number density to Dobson units for each Umkehr layer. The analysis reveals a negative bias in Umkehr data within -10% except at layer 6 (around 30 km).

  18. Ozone Temperature Correlations in the Upper Stratosphere as a Measure of Chlorine Content

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Douglass, Ann R.; Remsberg, Ellis E.; Livesey, Nathaniel J.; Gille, John C.

    2012-01-01

    We use data from the Nimbus-7 Limb Infrared Monitor of the Stratosphere (LIMS) for the 1978-1979 period together with data from the Upper Atmosphere Research Satellite Microwave Limb Sounder (UARS MLS) for the years 1993 to 1999, the Aura MLS for the years 2004 to 2011, and the Aura High Resolution Infrared Limb Sounder (HIRDLS) for the years 2005 to 2007 to examine ozone-temperature correlations in the upper stratosphere. Our model simulations indicate that the sensitivity coefficient of the ozone response to temperature (Delta ln(O3)/Delta.(l/T)) decreases as chlorine has increased in the stratosphere and should increase in the future as chlorine decreases. The data are in agreement with our simulation of the past. We also find that the sensitivity coefficient does not change in a constant-chlorine simulation. Thus the change in the sensitivity coefficient depends on the change in chlorine, but not on the change in greenhouse gases. We suggest that these and future data can be used to track the impact of chlorine added to the stratosphere and also to track the recovery of the stratosphere as chlorine is removed under the provisions of the Montreal Protocol.

  19. Evaluation of Near-Tropopause Ozone Distributions in the Global Modeling Initiative Combined Stratosphere/Troposphere Model with Ozonesonde Data

    NASA Technical Reports Server (NTRS)

    Considine, David B.; Logan, Jennifer A.; Olsen, Mark A.

    2008-01-01

    The NASA Global Modeling Initiative has developed a combined stratosphere/troposphere chemistry and transport model which fully represents the processes governing atmospheric composition near the tropopause. We evaluate model ozone distributions near the tropopause, using two high vertical resolution monthly mean ozone profile climatologies constructed with ozonesonde data, one by averaging on pressure levels and the other relative to the thermal tropopause. Model ozone is high biased at the SH tropical and NH midlatitude tropopause by approx. 45% in a 4 deg. latitude x 5 deg. longitude model simulation. Increasing the resolution to 2 deg. x 2.5 deg. increases the NH tropopause high bias to approx. 60%, but decreases the tropical tropopause bias to approx. 30%, an effect of a better-resolved residual circulation. The tropopause ozone biases appear not to be due to an overly vigorous residual circulation or excessive stratosphere/troposphere exchange, but are more likely due to insufficient vertical resolution or excessive vertical diffusion near the tropopause. In the upper troposphere and lower stratosphere, model/measurement intercomparisons are strongly affected by the averaging technique. NH and tropical mean model lower stratospheric biases are less than 20%. In the upper troposphere, the 2 deg. x 2.5 deg. simulation exhibits mean high biases of approx. 20% and approx. 35% during April in the tropics and NH midlatitudes, respectively, compared to the pressure averaged climatology. However, relative-to-tropopause averaging produces upper troposphere high biases of approx. 30% and 70% in the tropics and NH midlatitudes. This is because relative-to-tropopause averaging better preserves large cross-tropopause O3 gradients, which are seen in the daily sonde data, but not in daily model profiles. The relative annual cycle of ozone near the tropopause is reproduced very well in the model Northern Hemisphere midlatitudes. In the tropics, the model amplitude of the

  20. Stratospheric response to trace gas perturbations: changes in ozone and temperature distributions.

    PubMed

    Brasseur, G; Hitchman, M H

    1988-04-29

    The stratospheric concentration of trace gases released in the atmosphere as a result of human activities is increasing at a rate of 5 to 8 percent per year in the case of the chlorofluorocarbons (CFCs), 1 percent per year in the case of methane (CH(4)), and 0.25 percent per year in the case of nitrous oxide (N(2)O). The amount of carbon dioxide (CO(2)) is expected to double before the end of the 21st century. Even if the production of the CFCs remains limited according to the protocol for the protection of the ozone layer signed in September 1987 in Montreal, the abundance of active chlorine (2 parts per billion by volume in the early 1980s) is expected to reach 6 to7 parts per billion by volume by 2050. The impact of these increases on stratospheric temperature and ozone was investigated with a two-dimensional numerical model. The model includes interactive radiation, wave and mean flow dynamics, and 40 trace species. An increase in CFCs caused ozone depletion in the model, with the largest losses near the stratopause and, in the vertical mean, at high latitudes. Increased CO(2) caused ozone amounts to increase through cooling, with the largest increases again near 45 kilometers and at high latitudes. This CO(2)-induced poleward increase reduced the CFC-induced poleward decrease. Poleward and downward ozone transport played a major role in determining the latitudinal variation in column ozone changes.

  1. CHEOPS III: An ozone research campaign in the arctic winter stratosphere 1989/90

    SciTech Connect

    Pommereau, J.P. ); Schmidt, U. )

    1991-04-01

    CHEOPS ( = CHemistry of Ozone in the Polar Stratosphere) is a research project that began in 1987 as an initiative to join efforts of scientists from Germany and France combining their resources and capacities to conduct field experiments in the winter Arctic stratosphere. On February 5, two experiments, a cryogenic whole air sampler and an active chemical ionization mass spectrometer, were launched with a large scientific balloon from the ESA/SSC Rocket Base ESRANGE near Kiruna in Northern Sweden (68{degree} N, 20{degree} E). The scientific objective was to look for a possible latitudinal difference in the vertical distributions of various minor constituents in the lower and middle stratosphere during winter. The International Ozone Trends Panel reported a systematic decrease in total ozone by about 6% in the Arctic winter stratosphere over the period 1969-86. This finding motivated several European research groups to continue the CHEOPS program by regular field campaigns organized in the Arctic region. During the CHEOPS II campaign conducted in winter 1987/88 four payloads were launched in cooperation with the balloon launching team of the French Centre National d'Etudes Spatiales (CNES). On the basis of the tests and improvements of the instrumentation achieved during the previous winter campaign, CHEOPS III was planned for winter 1989/90 as a more ambitious field experiment. In addition to balloon-borne and ground-based observations, the program included an increased number of regular ozone sonde launches at various Scandinavian stations. The primary objective was to investigate the composition of the lower Arctic stratosphere during winter until early February, when temperatures were lowest and episodes of perturbed chemistry during PSC events were most likely to occur.

  2. The representation of solar cycle signals in stratospheric ozone - Part 1: A comparison of recently updated satellite observations

    NASA Astrophysics Data System (ADS)

    Maycock, Amanda C.; Matthes, Katja; Tegtmeier, Susann; Thiéblemont, Rémi; Hood, Lon

    2016-08-01

    Changes in incoming solar ultraviolet radiation over the 11-year solar cycle affect stratospheric ozone abundances. It is important to quantify the magnitude, structure, and seasonality of the associated solar-ozone response (SOR) to understand the impact of the 11-year solar cycle on climate. Part 1 of this two-part study uses multiple linear regression analysis to extract the SOR in a number of recently updated satellite ozone datasets covering different periods within the epoch 1970 to 2013. The annual mean SOR in the updated version 7.0 (v7.0) Stratospheric Aerosol and Gas Experiment (SAGE) II number density dataset (1984-2004) is very consistent with that found in the previous v6.2. In contrast, we find a substantial decrease in the magnitude of the SOR in the tropical upper stratosphere in the SAGE II v7.0 mixing ratio dataset (˜ 1 %) compared to the v6.2 (˜ 4 %). This difference is shown to be largely attributable to the change in the independent stratospheric temperature dataset used to convert SAGE II ozone number densities to mixing ratios. Since these temperature records contain substantial uncertainties, we suggest that datasets based on SAGE II number densities are currently most reliable for evaluating the SOR. We further analyse three extended ozone datasets that combine SAGE II v7.0 number densities with more recent GOMOS (Global Ozone Monitoring by Occultation of Stars) or OSIRIS (Optical Spectrograph and Infrared Imager System) measurements. The extended SAGE-OSIRIS dataset (1984-2013) shows a smaller and less statistically significant SOR across much of the tropical upper stratosphere compared to the SAGE II data alone. In contrast, the two SAGE-GOMOS datasets (1984-2011) show SORs that are in closer agreement with the original SAGE II data and therefore appear to provide a more reliable estimate of the SOR. We also analyse the SOR in the recent Solar Backscatter Ultraviolet Instrument (SBUV) Merged Ozone Dataset (SBUVMOD) version 8.6 (VN8

  3. 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...

  4. Understanding differences in upper stratospheric ozone response to changes in chlorine and temperature as computed using CCMVal-2 models

    NASA Astrophysics Data System (ADS)

    Douglass, A. R.; Stolarski, R. S.; Strahan, S. E.; Oman, L. D.

    2012-08-01

    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 coupled chemistry-climate models (CCMs). Although developed from common principles and subject to the same boundary conditions, simulated ozone time series vary among models for scenarios for ozone depleting substances (ODSs) and greenhouse gases. Photochemical processes control the upper stratospheric ozone level, and there is broad agreement among CCMs in that ozone increases as ODSs decrease and temperature decreases due to greenhouse gas increase. There are quantitative differences in the ozone sensitivity to chlorine and temperature. We obtain insight into differences in sensitivity by examining the relationship between the upper stratospheric seasonal cycles of ozone and temperature as produced by fourteen CCMs. 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. Analysis reveals differences in simulated temperature, ozone and reactive nitrogen that lead to differences in the relative importance of ozone loss processes and are most obvious when chlorine levels are close to background. Differences in the relative importance of loss processes underlie differences in simulated sensitivity of ozone to composition change. This suggests 1) that the multimodel mean is not a best estimate of the sensitivity of upper stratospheric ozone to changes in ODSs and temperature; and 2) that the spread of values is not an appropriate measure of uncertainty.

  5. Stratospheric Ozone Changes and Polar Mesospheric Cloud (PMC) Trends Observed in SBUV Data

    NASA Astrophysics Data System (ADS)

    DeLand, M. T.; Thomas, G. E.; Shettle, E. P.; Olivero, J. J.

    2013-12-01

    Polar mesospheric clouds (PMCs) are observed at 80-85 km altitude and high latitudes (typically > 50°) only during summer months. It has been suggested that long-term variations of PMC occurrence frequency and brightness are indicators of global climate change as represented through changes in mesospheric temperature and water vapor. The Solar Backscatter Ultraviolet (SBUV) series of satellite instruments, although designed to measure stratospheric profile and total column ozone, have made global observations of bright PMCs since November 1978. Previous analysis of SBUV data found that long-term variations in PMC brightness and occurrence frequency were anti-correlated with solar activity, and that a positive secular trend was present at most latitudes. The limited database of mesospheric temperature and water vapor data has precluded further determination of the source of this trend. Motivated by recent studies with the LIMA general circulation model [Berger and Lübken 2011], which relate mesospheric temperature trends to changes in stratospheric ozone, we have investigated the use of stratospheric ozone changes as a proxy for changes in mesospheric heating and temperature. The decrease in ozone from 1979 to the mid-1990s leads to a cooler mesosphere, and is thus consistent with the rise in PMC ice water content observed in the SBUV record during this period. Similarly, stratospheric ozone changes are smaller from the mid-1990s to the present, and PMC ice water content trends are also reduced in recent years. We will discuss these results and their implications for both previous (before 1979) and future PMC behavior.

  6. Radiative effects of polar stratospheric clouds during the Airborne Antarctic Ozone Experiment and the Airborne Arctic Stratospheric Expedition

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.

    1992-01-01

    Results are presented of a study of the radiative effects of polar stratospheric clouds during the Airborne Antarctic Ozone Experiment (AAOE) and the Airborne Arctic Stratospheric Expedition (AASE) in which daily 3D Type I nitric acid trihydrate (NAT) and Type II water ice polar stratospheric clouds (PSCs) were generated in the polar regions during AAOE and the AASE aircraft missions. Mission data on particular composition and size, together with NMC-analyzed temperatures, are used. For AAOE, both Type I and Type II clouds were formed for the time period August 23 to September 17, after which only Type I clouds formed. During AASE, while Type I clouds were formed for each day between January 3 and February 10, Type II clouds formed on only two days, January 24 and 31. Mie theory and a radiative transfer model are used to compute the radiative heating rates during the mission periods, for clear and cloudy lower sky cases. Only the Type II water ice clouds have a significant radiative effect, with the Type I NATO PSCs generating a net heating or cooling of 0.1 K/d or less.

  7. How sensitive is the recovery of stratospheric ozone to changes in concentrations of very short-lived bromocarbons?

    NASA Astrophysics Data System (ADS)

    Yang, X.; Abraham, N. L.; Archibald, A. T.; Braesicke, P.; Keeble, J.; Telford, P. J.; Warwick, N. J.; Pyle, J. A.

    2014-10-01

    Naturally produced very short-lived substances (VSLS) account for almost a quarter of the current stratospheric inorganic bromine, Bry. Following VSLS oxidation, bromine radicals (Br and BrO) can catalytically destroy ozone. The extent to which possible increases in surface emissions or transport of these VSLS bromocarbons to the stratosphere could counteract the effect of halogen reductions under the Montreal Protocol is an important policy question. Here, by using a chemistry-climate model, UM-UKCA, we investigate the impact of a hypothetical doubling (an increase of 5 ppt Bry) of VSLS bromocarbons on ozone and how the resulting ozone changes depend on the background concentrations of chlorine and bromine. Our model experiments indicate that for the 5 ppt increase in Bry from VSLS, the ozone decrease in the lowermost stratosphere of the Southern Hemisphere (SH) may reach up to 10% in the annual mean; the ozone decrease in the Northern Hemisphere (NH) is smaller (4-6%). The largest impact on the ozone column is found in the Antarctic spring. There is a significantly larger ozone decrease following the doubling of the VSLS burden under a high stratospheric chlorine background than under a low chlorine background, indicating the importance of the inter-halogen reactions. For example, the decline in the high-latitude, lower-stratospheric ozone concentration as a function of Bry is higher by about 30-40% when stratospheric Cly is ~ 3 ppb (present day), compared with Cly of ~ 0.8 ppb (a pre-industrial or projected future situation). Bromine will play an important role in the future ozone layer. However, even if bromine levels from natural VSLS were to increase significantly later this century, changes in the concentration of ozone will likely be dominated by the decrease in anthropogenic chlorine. Our calculation suggests that for a 5 ppt increase in Bry from VSLS, the Antarctic ozone hole recovery date could be delayed by approximately 6-8 years, depending on Cly

  8. The role of polar stratospheric clouds on total ozone minihole events

    NASA Technical Reports Server (NTRS)

    Sabutis, Joseph L.

    1989-01-01

    Using seven years of data from tha SAM 2 (Stratospheric Aerosol Measurement 2) and TOMS (Total Ozone Mapping Spectrometer) instruments, along with 70 mbar temperatures extracted from an NMC analysis, the effect of the austral spring polar stratospheric clouds (PSC) on the formation of total ozone miniholes is investigated. A total ozone minihole event is designated as the rapid decrease of more than 20 DU of total ozone over a time period of a day and a spatial extent of approximately 1000 by 1000 km. The severe decrease of total ozone during these minihole events could be explained in part by PSC being formed at altitudes of 10 to 24 km and preventing scattered UV radiation from ozone below the cloud from reaching the TOMS instrument. A result of the cloud's opaqueness is that the total ozone retrieval from TOMS data would underestimate the ozone column in the vicinity of the PSC. The approach to investigate the effect of PSC on total ozone was to use SAM 2 aerosol extinction values in conjunction with NMC stratospheric temperatures to determine if PSC are present during total ozone minihole events occurring during August and September, 1979 to 1986. The minihole events during these seven years were divided into two types: type 1, where the minihole region of 24 hour darkness from regions exposed to sunlight, and type 2, where the minihole occurred 5 to 10 degrees north of the terminator. The presence of PSC in a given region was ascertained by a maximum aerosol extinction greater than .006/km occurring with a temperature less than 189 K. It is found that PSC are consistently present with type 2 minihole events. This is contrasted with PSC rarely occurring in the same vicinity of type 2 miniholes. Also observed of that type 1 minihole events have minimum total ozone values which are on the average 3 to 10 DU smaller than type 2 miniholes. It can be concluded that care must be taken when trying to deduce a dynamical explanation of minihole events near the polar

  9. Solar Cycle Spectral Irradiance Variation and Stratospheric Ozone

    NASA Astrophysics Data System (ADS)

    Stolarski, R. S.; Swartz, W. H.; Jackman, C. H.; Fleming, E. L.

    2011-12-01

    Recent measurements from the SIM instrument on the SORCE satellite have been interpreted by Harder et al (Geophys. Res. Lett., 36, L07801, doi:10.1029/2008GL036797, 2009) as implying a different spectral irradiance variation over the solar cycle than that put forward by Lean (Geophys. Res. Lett., 27, 2425-2428, 2000). When we inserted this new wavelength dependent solar cycle variation into our 3D CCM we found a different solar cycle dependence of the ozone concentration as a function of altitude from that we derived using the traditional Lean wavelength dependence. Examination of these results led us to realize that the main issue is the solar cycle variation of radiation at wavelengths less than 240 nm versus the solar cycle variation of radiation at wavelengths between 240 nm and 300 nm. The impact of wavelengths less than 240 nm occurs through photodissociation of O2 leading to the production of ozone. The impact of wavelengths between 240 nm and 300 nm occurs through photodissociation of O3 leading to an increase in O atoms and enhanced ozone destruction. Thus one wavelength region gives an in-phase relationship of ozone with the solar cycle while the other wavelength region gives an out-of-phase relationship of ozone with the solar cycle. We have used the Goddard two-dimensional (2D) photochemistry transport model to examine this relationship in more detail. We calculate the altitude and latitude sensitivity of ozone to changes in the solar UV irradiance as a function of wavelength. These results can be used to construct the ozone response to arbitrary wavelength dependencies of solar UV variation.

  10. The sensitivity of stratospheric ozone changes through the 21st century to N2O and CH4

    NASA Astrophysics Data System (ADS)

    Revell, L. E.; Bodeker, G. E.; Huck, P. E.; Williamson, B. E.; Rozanov, E.

    2012-12-01

    Through the 21st century, anthropogenic emissions of the greenhouse gases N2O and CH4 are projected to increase, thus increasing their atmospheric concentrations. Consequently, reactive nitrogen species produced from N2O and reactive hydrogen species produced from CH4 are expected to play an increasingly important role in determining stratospheric ozone concentrations. Eight chemistry-climate model simulations were performed to assess the sensitivity of stratospheric ozone to different emissions scenarios for N2O and CH4. Global-mean total column ozone increases through the 21st century in all eight simulations as a result of CO2-induced stratospheric cooling and decreasing stratospheric halogen concentrations. Larger N2O concentrations were associated with smaller ozone increases, due to reactive nitrogen-mediated ozone destruction. In the simulation with the largest N2O increase, global-mean total column ozone increased by 4.3 DU through the 21st century, compared with 10.0 DU in the simulation with the smallest N2O increase. In contrast, larger CH4 concentrations were associated with larger ozone increases; global-mean total column ozone increased by 16.7 DU through the 21st century in the simulation with the largest CH4 concentrations and by 4.4 DU in the simulation with the lowest CH4 concentrations. CH4 leads to ozone loss in the upper and lower stratosphere by increasing the rate of reactive hydrogen-mediated ozone loss cycles, however in the lower stratosphere and troposphere, CH4 leads to ozone increases due to photochemical smog-type chemistry. In addition to this mechanism, total column ozone increases due to H2O-induced cooling of the stratosphere, and slowing of the chlorine-catalyzed ozone loss cycles due to an increased rate of the CH4 + Cl reaction. Stratospheric column ozone through the 21st century exhibits a near-linear response to changes in N2O and CH4 surface concentrations, which provides a simple parameterization for the ozone response to

  11. The capability of satellite borne remote sensors to measure stratospheric trace constituents. Volume 2: Ozone and aerosol related missions

    NASA Technical Reports Server (NTRS)

    Keitz, E. L.

    1978-01-01

    Stratospheric trace constituent measurement requirements are separated into two somewhat overlapping areas. In the first area, it is assumed that the only problem of interest is ozone; its chemistry chain, environmental effects and measurement requirements. In like manner, in the second area it is assumed that the only problem of interest is stratospheric aerosols; their chemistry, effects and measurement requirements.

  12. Total ozone, ozone vertical distributions, and stratospheric temperatures at South Pole, Antarctica, in 1986 and 1987

    NASA Technical Reports Server (NTRS)

    Komhyr, W. D.; Grass, R. D.; Reitelbach, P. J.; Franchois, P. R.; Kuester, S. E.

    1988-01-01

    Seventy-six electrochemical cell (ECC) ozonesondes were flown at South Pole, Antarctica, during 1987 in a continuing program to document year-round changes in Antarctica ozone that are dynamically and photochemically induced. Dobson spectrophotometer total ozone observations were also made. For the twilight months of March and September when Dobson instrument observations cannot be made at South Pole, total ozone amounts were deduced from the ECC ozonesonde soundings. ECC sonde total ozone data obtained during the polar night (April to August), supplemented the sparse total ozone data obtained from Dobson instrument moon observations. Similar ozone profile and total ozone observations were made at South Pole in 1986.

  13. Mobile lidar for simultaneous measurements of ozone, aerosols, and temperature in the stratosphere.

    PubMed

    Uchino, O; Tabata, I

    1991-05-20

    A Meteorological Research Institute Mark II mobile lidar was developed for simultaneous measurements of ozone, temperature, and aerosols in the stratosphere. The lidar consists of an XeCl laser, a Nd:YAG laser, and an 80-cm diam receiving telescope. The laser beams at three wavelengths (308, 355, and 532 nm) can be almost simultaneously transmitted. The purpose of this lidar is to study, for example, the aerosol impact on the ozone layer through radiative and photochemical processes, the aerosol impact on the Umkehr measurements after violent volcanic eruptions, and the interaction between temperature and ozone. The performance of the lidar system and some data about ozone, aerosols, and temperature are described.

  14. Satellite observation and mapping of wintertime ozone variability in the lower stratosphere

    NASA Technical Reports Server (NTRS)

    Geller, M. A.; Chi, Yuechen; Rood, R. B.; Douglass, A. R.; Kaye, J. A.; Allen, D. J.

    1993-01-01

    Comparison is made between 30 mbar ozone fields that are generated by a transport chemistry model utilizing the winds from the Goddard Space Flight Center stratospheric data assimilation system (STRATAN), observations from the LIMS instrument on Nimbus-7, and the ozone fields that result from 'flying' a mathematical simulation of LIMS observations through the transport chemistry model ozone fields. The modeled ozone fields were found to resemble the LIMS observations, but the model fields show much more temporal and spatial structure than do the LIMS observations. The 'satellite mapped' model results resemble the LIMS observations much more closely. These results are very consistent with the earlier discussions of satellite space-time sampling by Salby.

  15. Toward a Better Quantitative Understanding of Polar Stratospheric Ozone Loss

    NASA Technical Reports Server (NTRS)

    Frieler, K.; Rex, M.; Salawitch, R. J.; Canty, T.; Streibel, M.; Stimpfle, R. M.; Pfeilsticker, K.; Dorf, M.; Weisenstein, D. K.; Godin-Beekmann, S.

    2006-01-01

    Previous studies have shown that observed large O3 loss rates in cold Arctic Januaries cannot be explained with current understanding of the loss processes, recommended reaction kinetics, and standard assumptions about total stratospheric chlorine and bromine. Studies based on data collected during recent field campaigns suggest faster rates of photolysis and thermal decomposition of ClOOCl and higher stratospheric bromine concentrations than previously assumed. We show that a model accounting for these kinetic changes and higher levels of BrO can largely resolve the January Arctic O3 loss problem and closely reproduces observed Arctic O3 loss while being consistent with observed levels of ClO and ClOOCl. The model also suggests that bromine catalyzed O3 loss is more important relative to chlorine catalyzed loss than previously thought.

  16. Estimated SAGE II ozone mixing ratios in early 1993 and comparisons with Stratospheric Photochemistry, Aerosols and Dynamic Expedition measurements

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Veiga, R. E.; Poole, L. R.; Zawodny, J. M.; Proffitt, M. H.

    1994-01-01

    An empirical time-series model for estimating ozone mixing ratios based on Stratospheric Aerosols and Gas Experiment II (SAGE II) monthly mean ozone data for the period October 1984 through June 1991 has been developed. The modeling results for ozone mixing ratios in the 10- to 30- km region in early months of 1993 are presented. In situ ozone profiles obtained by a dual-beam UV-absorption ozone photometer during the Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE) campaign, May 1-14, 1993, are compared with the model results. With the exception of two profiles at altitudes below 16 km, ozone mixing ratios derived by the model and measured by the ozone photometer are in relatively good agreement within their individual uncertainties. The identified discrepancies in the two profiles are discussed.

  17. Seasonal Variation of Ozone in the Tropical Lower Stratosphere: Southern Tropics are Different from Northern Tropics

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Waugh, Darryn W.; Wang, Lei,; Oman, Luke D.; Douglass, Anne R.; Newman, Paul A.

    2014-01-01

    We examine the seasonal behavior of ozone by using measurements from various instruments including ozonesondes, Aura Microwave Limb Sounder, and Stratospheric Aerosol and Gas Experiment II. We find that the magnitude of the annual variation in ozone, as a percentage of the mean ozone, exhibits a maximum at or slightly above the tropical tropopause. The maximum is larger in the northern tropics than in the southern tropics, and the annual maximum of ozone in the southern tropics occurs 2 months later than that in the northern tropics, in contrast to usual assumption that the tropics can be treated as a horizontally homogeneous region. The seasonal cycles of ozone and other species in this part of the lower stratosphere result from a combination of the seasonal variation of the Brewer-Dobson circulation and the seasonal variation of tropical and midlatitude mixing. In the Northern Hemisphere, the impacts of upwelling and mixing between the tropics and midlatitudes on ozone are in phase and additive. In the Southern Hemisphere, they are not in phase. We apply a tropical leaky pipe model independently to each hemisphere to examine the relative roles of upwelling and mixing in the northern and southern tropical regions. Reasonable assumptions of the seasonal variation of upwelling and mixing yield a good description of the seasonal magnitude and phase in both the southern and northern tropics. The differences in the tracers and transport between the northern and southern tropical stratospheres suggest that the paradigm of well-mixed tropics needs to be revised to consider latitudinal variations within the tropics.

  18. Seasonal variation of ozone in the tropical lower stratosphere: Southern tropics are different from northern tropics

    NASA Astrophysics Data System (ADS)

    Stolarski, Richard S.; Waugh, Darryn W.; Wang, Lei; Oman, Luke D.; Douglass, Anne R.; Newman, Paul A.

    2014-05-01

    We examine the seasonal behavior of ozone by using measurements from various instruments including ozonesondes, Aura Microwave Limb Sounder, and Stratospheric Aerosol and Gas Experiment II. We find that the magnitude of the annual variation in ozone, as a percentage of the mean ozone, exhibits a maximum at or slightly above the tropical tropopause. The maximum is larger in the northern tropics than in the southern tropics, and the annual maximum of ozone in the southern tropics occurs 2 months later than that in the northern tropics, in contrast to usual assumption that the tropics can be treated as a horizontally homogeneous region. The seasonal cycles of ozone and other species in this part of the lower stratosphere result from a combination of the seasonal variation of the Brewer-Dobson circulation and the seasonal variation of tropical and midlatitude mixing. In the Northern Hemisphere, the impacts of upwelling and mixing between the tropics and midlatitudes on ozone are in phase and additive. In the Southern Hemisphere, they are not in phase. We apply a tropical leaky pipe model independently to each hemisphere to examine the relative roles of upwelling and mixing in the northern and southern tropical regions. Reasonable assumptions of the seasonal variation of upwelling and mixing yield a good description of the seasonal magnitude and phase in both the southern and northern tropics. The differences in the tracers and transport between the northern and southern tropical stratospheres suggest that the paradigm of well-mixed tropics needs to be revised to consider latitudinal variations within the tropics.

  19. Diurnal variation of oxygen isotopic enrichment in asymmetric-18 ozone from the middle stratosphere to lower mesosphere

    NASA Astrophysics Data System (ADS)

    Sato, Tomohiro; Kasai, Yasuko; Yoshida, Naohiro

    2016-07-01

    Oxygen isotopic signature is a powerful tracer of chemical and physical processes in the earth's atmosphere. Ozone has the largest oxygen isotopic enrichment in other oxygen-included species and is a source of oxygen isotopic enrichment. The vertical profile of ozone isotopic enrichment has been measured; however its variation over time remains uninvestigated. As ozone isotopic enrichment is generated by the ozone formation reaction and ozone photolysis, ozone isotopic enrichment is expected to vary over the course of a day. In this paper, the diurnal variation in oxygen isotopic enrichment of asymmetric 18 heavy ozone (δ^{18}OOO) was reported from the middle stratosphere to the lower mesosphere for the first time. We used the Level 2 vertical profile data derived from the atmospheric limb emission spectra acquired by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) with the optimized retrieval algorithm for ozone isotopic ratio by SMILES (TOROROS). In the middle stratosphere, δ^{18}OOO increased during the day with amplitudes of approximately 3.5 % and 2.2 % at 32 and 37 km, respectively. No significant variation was observed in the upper stratosphere and lower mesosphere, although δ^{18}OOO tended to decrease during the day with increasing altitude. This trend is opposite to that observed in the stratosphere. We estimated the diurnal variation in δ^{18}OOO with isotopic fractionation of ozone photolysis calculated by the photolysis rates of major and minor ozones. The estimation reproduced the daytime increase in the stratosphere and daytime decrease in the mesosphere. The contributions of ozone photolysis to the daytime increase were approximately 70 % and 80 % at 32 and 37 km, respectively. The daytime increase at an altitude of 32 km was underestimated, which indicates possible contributions from other chemical reactions such as collision with NO_x species. We concluded that ozone photolysis plays a key role in determining the diurnal

  20. Stratospheric Ozone Variations Caused by Solar Proton Events between 1963 and the Present

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Fleming, Eric L.

    2007-01-01

    Solar proton fluxes have been measured by satellites for over forty years (1963-present). Several satellites, including the Interplanetary Monitoring Platforms (1963-1993) and the NOAA Geostationary Operational Environmental Satellites (1994-present), have been used to compile this long-term dataset. Some solar storms lead to solar proton events (SPEs) at the Earth, which typically last a few days. High energy solar protons associated with SPEs precipitate on the Earth's atmosphere and cause increases in odd hydrogen (HO(x)) and odd nitrogen (NO(y)) in the polar cap region (>60 degrees geomagnetic). The enhanced HO(x) leads to short-lived ozone depletion (-days) due to the short lifetime of HOx constituents. The enhanced NO(y) leads to long-lived ozone changes because of the long lifetime of the NO(y) family in the stratosphere and lower mesosphere. Very large SPEs occurred in 1972, 1989, 2000, 2001, and 2003 and were predicted to cause significant polar upper stratospheric ozone depletion (>10%), which lasted for several weeks past the events. Several satellite instruments (BUV, SBUV, SBUV/2, SAGE II, HALOE, SCIAMACHY, MIPAS, GOMOS, etc.) have measured ozone changes as a result of SPEs. The long-term influence of SPEs on ozone will be discussed in this presentation.

  1. Results from the 1995 Stratospheric Ozone Profile Intercomparison at Mauna Loa (MLO3)

    NASA Technical Reports Server (NTRS)

    McPeters, R. D.; Hofmann, D. J.; Clark, M.; Flynn, L.; Froidevaux, L.; Gross, M.; Johnson, B.; Koenig, G.; Liu, X.; McDermid, S.; McGee, T.; Murcray, F.; Newchurch, M. J.; Oltmans, S.; Parrish, A.; Schnell, R.; Singh, U.; Tsou, J. J.; Walsh, T.; Zawodny, J. M.

    1998-01-01

    In August 1995 multiple instruments that measure the stratospheric ozone vertical distribution were intercompared at the Mauna Loa Observatory, Hawaii, under the auspices of the Network for the Detection of Stratospheric Change. The instruments included two UV lidar systems, one from JPL and the other from Goddard Space Flight Center, ECC balloon-sondes, a ground-based microwave instrument, Umkehr measurements, and a new ground-based FTIR instrument. The MLS instrument on the UARS satellite provided correlative profiles of ozone, and there was one close overpass of the SAGE II instrument. The results show that much better consistency among instruments is being achieved than even a few years ago, usually to within the instrument uncertainties. The different measurement techniques in this comparison agree to within +/-10% at almost all altitudes, and in the 20 km to 45 km region most agreed within +/-5%. The results show that the current generation of lidars are capable of accurate measurement of the ozone profile to a maximum altitude of 50 km. SAGE agreed well with both lidar and balloon-sonde down to at least 17 km. The ground-based microwave measurement agreed with other measurements from 22 km to above 50 km. One minor source of disagreement continues to be the pressure-altitude conversion needed to compare a measurement of ozone density versus altitude with a measurement of ozone mixing ratio versus pressure.

  2. The impact of stratospheric ozone depletion on the surface energy budget of Antarctica

    NASA Astrophysics Data System (ADS)

    Chiodo, G.; Polvani, L. M.; Previdi, M. J.

    2015-12-01

    It is now well established that stratospheric ozone depletion has been one of the dominant drivers of recent climate change in the mid-latitudes of the Southern Hemisphere. However, the effects of ozone depletion on Antarctic climate change during the past several decades are much more uncertain. Here, we examine the impact of ozone depletion on the Antarctic surface energy budget using a suite of simulations from the Community Earth System Model-Whole Atmosphere Community Climate Model (CESM-WACCM). CESM-WACCM is a state-of-the-art atmosphere-ocean general circulation model that includes interactive stratospheric chemistry, as well as a dynamic-thermodynamic sea-ice scheme. We performed two sets of integrations with WACCM for the period 1960-2005, each consisting of ∼6 ensemble members. In the first set of integrations, the model was driven with all time-varying natural and anthropogenic forcings, most notably the observed increases in ozone-depleting substances (ODSs) and other well-mixed greenhouse gases. The second set of 6 integrations is identical to the first, except that ODSs are kept fixed at 1960 levels, thus preventing the model from developing a springtime Antarctic stratospheric ozone hole. Comparison between these two ensembles of simulations therefore unambiguously quantifies the impact of ozone depletion on the Antarctic surface energy budget. We find that the decrease in stratospheric ozone concentrations in recent decades leads to an increase of 2-3 W/m2 in incident (downward) shortwave radiation at the Antarctic surface during austral spring and summer. However, due to a concomitant increase in surface reflectivity, there is little change in net shortwave radiation in the model simulations. Downward long-wave emission increases as a consequence of greenhouse gases in both ensembles, while latent and sensible heat fluxes do not change significantly. Taken together, these results indicate that ozone depletion alone has a negligible effect on

  3. Long-term Evolution of Upper Stratospheric Ozone at Selected Stations of the Network for the Detection of Stratospheric Change (NDSC)

    NASA Technical Reports Server (NTRS)

    Steinbrecht, W.; Claude, H.; Schoenenborn, F.; McDermid, I. S.; LeBlanc, T.; Godin, S.; Swart, D. P. J.; Meijer, Y. J.; Bodecker, G. E.; Connor, B. J.; Kaempfer, N.; Hocke, K.; Calisesi, Y.; delaNoee; Parrish, A. D.; Boyd, I. S.; Bruehl, C.; Steil, B.; Manzini, E.; Thomason, L. W.; Zawodny, J. M.; McCormick, M. P.; Russell, J. M., III; Bhartia, P. K.; Stolarski, R. S.

    2006-01-01

    The long-term evolution of upper stratospheric ozone has been recorded by lidars and microwave radiometers within the ground-based Network for the Detection of Stratospheric Change (NDSC), and by the space-borne Solar Backscatter Ultra-Violet instruments (SBUV), Stratospheric Aerosol and Gas Experiment (SAGE), and Halogen Occultation Experiment (HALOE). Climatological mean differences between these instruments are typically smaller than 5% between 25 and 50 km. Ozone anomaly time series from all instruments, averaged from 35 to 45 km altitude, track each other very well and typically agree within 3 to 5%. SBUV seems to have a slight positive drift against the other instruments. The corresponding 1979 to 1999 period from a transient simulation by the fully coupled MAECHAM4-CHEM chemistry climate model reproduces many features of the observed anomalies. However, in the upper stratosphere the model shows too low ozone values and too negative ozone trends, probably due to an underestimation of methane and a consequent overestimation of ClO. The combination of all observational data sets provides a very consistent picture, with a long-term stability of 2% or better. Upper stratospheric ozone shows three main features: (1) a decline by 10 to 15% since 1980, due to chemical destruction by chlorine; (2) two to three year fluctuations by 5 to 10%, due to the Quasi-Biennial Oscillation (QBO); (3) an 11-year oscillation by about 5%, due to the 11-year solar cycle. The 1979 to 1997 ozone trends are larger at the southern mid-latitude station Lauder (45 S), reaching 8%/decade, compared to only about 6%/decade at Table Mountain (35 N), Haute Provence/Bordeaux (approximately equal to 45 N), and Hohenpeissenberg/Bern(approximately equal to 47 N). At Lauder, Hawaii (20 N), Table Mountain, and Haute Provence, ozone residuals after subtraction of QBO- and solar cycle effects have levelled off in recent years, or are even increasing. Assuming a turning point in January 1997, the

  4. Impact of high speed civil transports on stratospheric ozone: A 2-D model investigation

    SciTech Connect

    Kinnison, D.E.; Connell, P.S.

    1996-12-01

    This study investigates the effect on stratospheric ozone from a fleet of proposed High Speed Civil Transports (HSCTs). The new LLNL 2-D operator-split chemical-radiative-transport model of the troposphere and stratosphere is used for this HSCT investigation. This model is integrated in a diurnal manner, using an implicit numerical solver. Therefore, rate coefficients are not modified by any sort of diurnal average factor. This model also does not make any assumptions on lumping of chemical species into families. Comparisons to previous model-derived HSCT assessment of ozone change are made, both to the previous LLNL 2-D model and to other models from the international assessment modeling community. The sensitivity to the NO{sub x} emission index and sulfate surface area density is also explored.

  5. The impact of stratospheric ozone recovery on the Southern Hemisphere westerly jet.

    PubMed

    Son, S-W; Polvani, L M; Waugh, D W; Akiyoshi, H; Garcia, R; Kinnison, D; Pawson, S; Rozanov, E; Shepherd, T G; Shibata, K

    2008-06-13

    In the past several decades, the tropospheric westerly winds in the Southern Hemisphere have been observed to accelerate on the poleward side of the surface wind maximum. This has been attributed to the combined anthropogenic effects of increasing greenhouse gases and decreasing stratospheric ozone and is predicted to continue by the Intergovernmental Panel on Climate Change/Fourth Assessment Report (IPCC/AR4) models. In this paper, the predictions of the Chemistry-Climate Model Validation (CCMVal) models are examined: Unlike the AR4 models, the CCMVal models have a fully interactive stratospheric chemistry. Owing to the expected disappearance of the ozone hole in the first half of the 21st century, the CCMVal models predict that the tropospheric westerlies in Southern Hemisphere summer will be decelerated, on the poleward side, in contrast with the prediction of most IPCC/AR4 models. PMID:18556557

  6. Chlorine oxide in the stratospheric ozone layer: ground-based detection and measurement.

    PubMed

    Parrish, A; DE Zafra, R L; Solomon, P M; Barrett, J W; Carlson, E R

    1981-03-13

    Stratospheric chlorine oxide, a significant intermediate product in the catalytic destruction of ozone by atomic chlorine, has been detected and measured by a ground-based 204-gigahertz, millimeter-wave receiver. Data taken at latitude 42 degrees N on 17 days between 10 January and 18 February 1980 yield an average chlorine oxide column density of approximately 1.05 x 10(14) per square centimeter or approximately 2/3 that of the average of eight in situ balloon flight measurements (excluding the anomalously high data of 14 July 1977) made over the past 4 years at 32 degrees N. We find less chlorine oxide below 35 kilometers and a larger vertical gradient than predicted by theoretical models of the stratospheric ozone layer.

  7. Chlorine oxide in the stratospheric ozone layer Ground-based detection and measurement

    NASA Technical Reports Server (NTRS)

    Parrish, A.; De Zafra, R. L.; Solomon, P. M.; Barrett, J. W.; Carlson, E. R.

    1981-01-01

    Stratospheric chlorine oxide, a significant intermediate product in the catalytic destruction of ozone by atomic chlorine, has been detected and measured by a ground-based 204 GHz, millimeter-wave receiver. Data taken at latitude 42 deg N on 17 days between January 10 and February 18, 1980 yield an average chlorine oxide column density of approximately 1.05 x 10 to the 14th/sq cm or approximately 2/3 that of the average of eight in situ balloon flight measurements (excluding the anomalously high data of July 14, 1977) made over the past four years at 32 deg N. Less chlorine oxide below 35 km and a larger vertical gradient than predicted by theoretical models of the stratospheric ozone layer are found.

  8. 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.

  9. Middle-atmospheric Ozone and HCl anomalies during the polar stratospheric warming 2010 observed by JEM/SMILES

    NASA Astrophysics Data System (ADS)

    Esmaeili Mahani, M.; Kreyling, D.; Sagawa, H.; Murata, I.; Kasaba, Y.; Kasai, Y.

    2012-12-01

    In this study we focused on investigating ozone and HCl variations and anomalies in the middle atmosphere due to the Stratospheric Sudden Warming (SSW) event of Arctic winter 2009-2010 using JEM/SMILES data. HCl anomalies in evolution of a SSW have been studied for the first time. SSWs are dramatic events in the winter stratosphere of the Northern Hemisphere where the deceleration or reversal of the eastward winds is accompanied by an increase of temperature by several tens of degrees. The main cause of this phenomenon is known to be the interaction of zonal mean flow with upward propagating transient planetary waves from the troposphere in mid-winter leading to a vortex displacement or break down. SSWs are dynamical disturbances found to affect both dynamics and chemical compositions of the middle atmosphere still having several different atmospheric features and behaviors to be studied. The Superconducting sub-Millimeter Limb Emission Sounder (SMILES) is a highly sensitive radiometer to observe various atmospheric compositions from upper troposphere to the mesosphere. SMILES was developed by the Japanese Aerospace eXploration Agency (JAXA) and the National Institute of Communications and Technology (NICT) located at the Japanese Experiment Module (JEM) on board the International Space Station (ISS). From October 2009 to April 2010, SMILES has accurately measured the vertical distributions and the diurnal variations of for example ozone and HCl with the accuracy of less than 8% and 5% in the middle atmosphere respectively. By using SMILES data the SSW event of 2010 was confirmed on 25-January categorized as a major, vortex displacement warming. After the SSW, ozone values enhanced up to 15-20% in mid-stratosphere due to the meridional transport from lower latitudes and weakening of the polar vortex. The mesospheric ozone response will also be demonstrated and discussed. For HCl, the total increase of 10% in Upper Stratosphere Lower Mesosphere (USLM) before the

  10. Aircraft HO sub x and NO sub x emission effects on stratospheric ozone and temperature

    NASA Technical Reports Server (NTRS)

    Glatt, L.; Widhopf, G. F.

    1978-01-01

    A simplified two-dimensional steady-state photochemical model of the atmosphere was developed. The model was used to study the effect on the thermal and chemical structure of the atmosphere of two types of pollution cases: (1) injection of NOx and HOx from a hypothetical fleet of supersonic and subsonic aircraft and (2) injection of HOx from a hypothetical fleet of liquid-fueled hydrogen aircraft. The results are discussed with regard to stratospheric perturbations in ozone, water vapor and temperature.

  11. On a period with very low ozone concentrations within the lower stratosphere

    SciTech Connect

    Wege, K.; Claude, H. )

    1994-06-22

    This paper presents a summary of ozone measurements made above Hohenpeissenberg (48[degrees]N) during the winter of 1991-1992. The column measurements were down by roughly 10 percent, while densities in the lower stratosphere were down by 25 percent. Possible causes of these decreases, including increased freon concentrations, or the presence of meteorological disturbances over the area have been eliminated as possible causes. The presence of aerosol layers from the Mt. Pinatubo eruptions are a possible explanation for these observations.

  12. Energetic radiation belt electron precipitation: a natural depletion mechanism for stratospheric ozone.

    PubMed

    Thorne, R M

    1977-01-21

    During geomagnetically disturbed periods the precipitational loss of energetic electrons from the outer radiation belt of the earth can readily provide the major ionization source for the mesosphere and upper stratosphere. One particularly intense manifestation of this interaction between the radiation belts and the lower atmosphere is the relativistic electron precipitation (REP) event which occurs at subauroral latitudes during magnetospheric substorm activity. At relativistic energies the precipitating electrons produce copious fluxes of energetic bremsstrahlung x-rays, the major portion of which penetrate deep into the stratosphere before undergoing excitation and ionization collisions with the neutral atmosphere. If such REP events occur more than a few percent of the time, they can, on an annual basis, provide a local source of upper stratospheric nitric oxide molecules (via the dissociation of molecular nitrogen) comparable to that from either galactic cosmic rays or energetic solar proton events. Since nitric oxide plays a major role in the removal of stratospheric ozone, it appears that the influence of REP events must also be considered in future photochemical modeling of the terrestrial ozone layer.

  13. Stratospheric photochemical studies using Nimbus 7 data. I - Ozone photochemistry. II - Development of inferred trace specie distributions

    NASA Technical Reports Server (NTRS)

    Natarajan, M.; Lambeth, J. D.; Callis, L. B.; Boughner, R. E.; Russell, J. M., III

    1986-01-01

    The present investigation has the objective to make use of the limb infrared monitor of the stratosphere (LIMS) data set in conducting stratospheric photochemical studies. A description of the data is provided. The data are utilized in a zero-dimensional model incorporating the relevant chemistry. The chemical reaction scheme considered is a subset of the scheme used in the Langley one-dimensional model discussed by Callis et al. (1983). Attention is given to a comparison of model results and data, a model uncertainty analysis, model response to modifications in rate data, the ozone-temperature relationship, and the diurnal variation in the upper stratospheric ozone.

  14. Satellite measurements of the Madden-Julian oscillation in wintertime stratospheric ozone over the Tibetan Plateau and East Asia

    NASA Astrophysics Data System (ADS)

    Zhang, Yuli; Liu, Yi; Liu, Chuanxi; Sofieva, V. F.

    2015-11-01

    We investigate the Madden-Julian Oscillation (MJO) signal in wintertime stratospheric ozone over the Tibetan Plateau and East Asia using the harmonized dataset of satellite ozone profiles. Two different MJO indices—the all-season Real-Time multivariate MJO index (RMM) and outgoing longwave radiation-based MJO index (OMI)—are used to compare the MJO-related ozone anomalies. The results show that there are pronounced eastward-propagating MJO-related stratospheric ozone anomalies (mainly within 20-200 hPa) over the subtropics. The negative stratospheric ozone anomalies are over the Tibetan Plateau and East Asia in MJO phases 4-7, when MJO-related tropical deep convective anomalies move from the equatorial Indian Ocean towards the western Pacific Ocean. Compared with the results based on RMM, the MJO-related stratospheric column ozone anomalies based on OMI are stronger and one phase ahead. Further analysis suggests that different sampling errors, observation principles and retrieval algorithms may be responsible for the discrepancies among different satellite measurements. The MJO-related stratospheric ozone anomalies can be attributed to the MJO-related circulation anomalies, i.e., the uplifted tropopause and the northward shifted westerly jet in the upper troposphere. Compared to the result based on RMM, the upper tropospheric westerly jet may play a less important role in generating the stratospheric column ozone anomalies based on OMI. Our study indicates that the circulation-based MJO index (RMM) can better characterize the MJO-related anomalies in tropopause pressure and thus the MJO influence on atmospheric trace gases in the upper troposphere and lower stratosphere, especially over subtropical East Asia.

  15. Climate variability modulates western US ozone air quality in spring via deep stratospheric intrusions

    PubMed Central

    Lin, Meiyun; Fiore, Arlene M.; Horowitz, Larry W.; Langford, Andrew O.; Oltmans, Samuel J.; Tarasick, David; Rieder, Harald E.

    2015-01-01

    Evidence suggests deep stratospheric intrusions can elevate western US surface ozone to unhealthy levels during spring. These intrusions can be classified as ‘exceptional events', which are not counted towards non-attainment determinations. Understanding the factors driving the year-to-year variability of these intrusions is thus relevant for effective implementation of the US ozone air quality standard. Here we use observations and model simulations to link these events to modes of climate variability. We show more frequent late spring stratospheric intrusions when the polar jet meanders towards the western United States, such as occurs following strong La Niña winters (Niño3.4<−1.0 °C). While El Niño leads to enhancements of upper tropospheric ozone, we find this influence does not reach surface air. Fewer and weaker intrusion events follow in the two springs after the 1991 volcanic eruption of Mt. Pinatubo. The linkage between La Niña and western US stratospheric intrusions can be exploited to provide a few months of lead time during which preparations could be made to deploy targeted measurements aimed at identifying these exceptional events. PMID:25964012

  16. Climate variability modulates western US ozone air quality in spring via deep stratospheric intrusions

    NASA Astrophysics Data System (ADS)

    Lin, Meiyun; Fiore, Arlene M.; Horowitz, Larry W.; Langford, Andrew O.; Oltmans, Samuel J.; Tarasick, David; Rieder, Harald E.

    2015-05-01

    Evidence suggests deep stratospheric intrusions can elevate western US surface ozone to unhealthy levels during spring. These intrusions can be classified as `exceptional events', which are not counted towards non-attainment determinations. Understanding the factors driving the year-to-year variability of these intrusions is thus relevant for effective implementation of the US ozone air quality standard. Here we use observations and model simulations to link these events to modes of climate variability. We show more frequent late spring stratospheric intrusions when the polar jet meanders towards the western United States, such as occurs following strong La Niña winters (Niño3.4<-1.0 °C). While El Niño leads to enhancements of upper tropospheric ozone, we find this influence does not reach surface air. Fewer and weaker intrusion events follow in the two springs after the 1991 volcanic eruption of Mt. Pinatubo. The linkage between La Niña and western US stratospheric intrusions can be exploited to provide a few months of lead time during which preparations could be made to deploy targeted measurements aimed at identifying these exceptional events.

  17. Results from the Jet Propulsion Laboratory stratospheric ozone lidar during STOIC 1989

    NASA Astrophysics Data System (ADS)

    McDermid, I. Stuart; Godin, Sophie M.; Walsh, T. Daniel

    1995-05-01

    Stratospheric ozone concentration profiles measured by the Jet Propulsion Laboratory differential absorption lidar system during the Stratospheric Ozone Intercomparison Campaign in July/August 1989 are presented. These profiles are compared with the mean profiles based on all of the measurements made by the different participating instruments. The results from the blind intercomparison showed that the lidar results agreed with the overall Stratospheric Ozone Intercomparison Campaign average profile to better than 5% between 21 and 45 km altitude. At 20 km the difference was ˜10%, as it was also in the region from 47 to 50 km altitude. Some systematic features were observed in the comparison of the blind results and these were subsequently investigated. The results of this investigation allowed the analysis algorithm to be refined and improved. The changes made are discussed and the comparison of the refined results showed agreement with the STOIC average to better than 4% from 18 to 48 km altitude. For both cases the results above 45 km altitude are subject to the greatest uncertainty and error and are of questionable value even though they agree within 10% with the STOIC average. Examples of comparisons of individual lidar profiles with each of the other instruments are also presented.

  18. Climate variability modulates western US ozone air quality in spring via deep stratospheric intrusions.

    PubMed

    Lin, Meiyun; Fiore, Arlene M; Horowitz, Larry W; Langford, Andrew O; Oltmans, Samuel J; Tarasick, David; Rieder, Harald E

    2015-01-01

    Evidence suggests deep stratospheric intrusions can elevate western US surface ozone to unhealthy levels during spring. These intrusions can be classified as 'exceptional events', which are not counted towards non-attainment determinations. Understanding the factors driving the year-to-year variability of these intrusions is thus relevant for effective implementation of the US ozone air quality standard. Here we use observations and model simulations to link these events to modes of climate variability. We show more frequent late spring stratospheric intrusions when the polar jet meanders towards the western United States, such as occurs following strong La Niña winters (Niño3.4<-1.0 °C). While El Niño leads to enhancements of upper tropospheric ozone, we find this influence does not reach surface air. Fewer and weaker intrusion events follow in the two springs after the 1991 volcanic eruption of Mt. Pinatubo. The linkage between La Niña and western US stratospheric intrusions can be exploited to provide a few months of lead time during which preparations could be made to deploy targeted measurements aimed at identifying these exceptional events. PMID:25964012

  19. 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

    It is well-understood that reductions in air quality play a significant role in both environmental and human health. Interactions between ozone depletion and global climate change will significantly alter atmospheric chemistry which, in turn, will cause changes in concentrations of natural and human-made gases and aerosols. Models predict that tropospheric ozone near the surface will increase globally by up to 10 to 30 ppbv (33 to 100% increase) during the period 2000 to 2100. With the increase in the amount of the stratospheric ozone, increased transport from the stratosphere to the troposphere will result in different responses in polluted and unpolluted areas. In contrast, global changes in tropospheric hydroxyl radical (OH) are not predicted to be large, except where influenced by the presence of oxidizable organic matter, such as from large-scale forest fires. Recent measurements in a relatively clean location over 5 years showed that OH concentrations can be predicted by the intensity of solar ultraviolet radiation. If this relationship is confirmed by further observations, this approach could be used to simplify assessments of air quality. Analysis of surface-level ozone observations in Antarctica suggests that there has been a significant change in the chemistry of the boundary layer of the atmosphere in this region as a result of stratospheric ozone depletion. The oxidation potential of the Antarctic boundary layer is estimated to be greater now than before the development of the ozone hole. Recent modeling studies have suggested that iodine and iodine-containing substances from natural sources, such as the ocean, may increase stratospheric ozone depletion significantly in polar regions during spring. Given the uncertainty of the fate of iodine in the stratosphere, the results may also be relevant for stratospheric ozone depletion and measurements of the influence of these substances on ozone depletion should be considered in the future. In agreement with

  20. 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

    It is well-understood that reductions in air quality play a significant role in both environmental and human health. Interactions between ozone depletion and global climate change will significantly alter atmospheric chemistry which, in turn, will cause changes in concentrations of natural and human-made gases and aerosols. Models predict that tropospheric ozone near the surface will increase globally by up to 10 to 30 ppbv (33 to 100% increase) during the period 2000 to 2100. With the increase in the amount of the stratospheric ozone, increased transport from the stratosphere to the troposphere will result in different responses in polluted and unpolluted areas. In contrast, global changes in tropospheric hydroxyl radical (OH) are not predicted to be large, except where influenced by the presence of oxidizable organic matter, such as from large-scale forest fires. Recent measurements in a relatively clean location over 5 years showed that OH concentrations can be predicted by the intensity of solar ultraviolet radiation. If this relationship is confirmed by further observations, this approach could be used to simplify assessments of air quality. Analysis of surface-level ozone observations in Antarctica suggests that there has been a significant change in the chemistry of the boundary layer of the atmosphere in this region as a result of stratospheric ozone depletion. The oxidation potential of the Antarctic boundary layer is estimated to be greater now than before the development of the ozone hole. Recent modeling studies have suggested that iodine and iodine-containing substances from natural sources, such as the ocean, may increase stratospheric ozone depletion significantly in polar regions during spring. Given the uncertainty of the fate of iodine in the stratosphere, the results may also be relevant for stratospheric ozone depletion and measurements of the influence of these substances on ozone depletion should be considered in the future. In agreement with

  1. Polar stratospheric clouds and the Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Poole, Lamont R.; Mccormick, M. Patrick

    1988-01-01

    A theoretical model for the formation and growth of polar stratospheric clouds (PSCs) has been developed. Results for the calculated temperature dependence of optical backscattering are found to agree well with values obtained during two Arctic airborne-lidar experiments. Results for PSC formation in Antarctica show that at the 70-mbar level, about 80 percent of the HNO3 and about 30 percent of the H2O vapor available may be sequestered in relatively large PSC particles at a temperature near 189 K.

  2. Lidar Measurements of Stratospheric Ozone, Aerosols and Temperature during the SAUNA Campaign at Sodankyla, Finland

    NASA Technical Reports Server (NTRS)

    McGee, T.; Twigg, L.; Sumnicht, G.; McPeters, R.; Bojkov, B.; Kivi, R.

    2008-01-01

    The Sodankyla Total Column Ozone Intercomparison (SAUNA) campaign took place at the Finnish Meteorological Institute Arctic Research Center (FMI-ARC) at Sodankyla, Finland (67.37 N) in two separate phases during early spring 2006, and winter 2007. These campaigns has several goals: to determine and improve the accuracy of total column ozone measurements during periods of low solar zenith angle and high total column ozone; to determine the effect of ozone profile shape on the total column retrieval; and to make validate satellite ozone measurements under these same conditions. The GSFC Stratospheric Ozone Lidar (STROZ), which makes profile measurements of ozone temperature, aerosols and water vapor participated in both phases of the campaign. During the deployments, more than 30 profile measurements were made by the lidar instrument, along with Dobson, Brewer, DOAS, ozonesonde, and satellite measurements. The presentation will concentrate on STROZ lidar results from the second phase of the campaign and comparisons with other instruments will be discussed. This will include both ground-based and satellite comparisons.

  3. Global Assimilation of EOS-Aura Data as a Means of Mapping Ozone Distribution in the Lower Stratosphere and Troposphere

    NASA Technical Reports Server (NTRS)

    Wargan, Krzysztof; Olsen, M.; Douglass, A.; Witte, J.; Strahan, S.; Livesey, N.

    2012-01-01

    Ozone in the lower stratosphere and the troposphere plays an important role in forcing the climate. However, the global ozone distribution in this region is not well known because of the sparse distribution of in-situ data and the poor sensitivity of satellite based observations to the lowermost of the atmosphere. The Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) instruments on EOS-Aura provide information on the total ozone column and the stratospheric ozone profile. This data has been assimilated into NASA s Global Earth Observing System, Version 5 (GEOS-5) data assimilation system (DAS). We will discuss the results of assimilating three years of OMI and MLS data into GEOS-5. This data was assimilated alongside meteorological observations from both conventional sources and satellite instruments. Previous studies have shown that combining observations from these instruments through the Trajectory Tropospheric Ozone Residual methodology (TTOR) or using data assimilation can yield useful, yet low biased, estimates of the tropospheric ozone budget. We show that the assimilated ozone fields in this updated version of GEOS-5 exhibit an excellent agreement with ozone sonde and High Resolution Dynamics Limb Sounder (HIRDLS) data in the lower stratosphere in terms of spatial and temporal variability as well as integrated ozone abundances. Good representation of small-scale vertical features follows from combining the MLS data with the assimilated meteorological fields. We then demonstrate how this information can be used to calculate the Stratosphere - Troposphere Exchange of ozone and its contribution to the tropospheric ozone column in GEOS-5. Evaluations of tropospheric ozone distributions from the assimilation will be made by comparisons with sonde and other in-situ observations.

  4. A New NASA Data Product: Tropospheric and Stratospheric Column Ozone in the Tropics Derived from TOMS Measurements

    NASA Technical Reports Server (NTRS)

    Ziemke, J. R.; Chandra, S.; Bhartia, P. K.

    1999-01-01

    Tropospheric column ozone (TCO) and stratospheric column ozone (SCO) gridded data in the tropics for 1979-present are now available from NASA Goddard Space Flight Center via either direct ftp, world-NN,ide-NN,eb, or electronic mail. This note provides a brief overview of the method used to derive the data set including validation and adjustments.

  5. How sensitive is the recovery of stratospheric ozone to changes in concentrations of very short lived bromocarbons?

    NASA Astrophysics Data System (ADS)

    Yang, X.; Abraham, N. L.; Archibald, A. T.; Braesicke, P.; Keeble, J.; Telford, P.; Warwick, N. J.; Pyle, J. A.

    2014-04-01

    Naturally produced very short-lived substances (VSLS), like bromocarbons, account for almost a quarter of the current stratospheric inorganic bromine, Bry. Following VSLS oxidation, bromine radicals (Br and BrO) can catalytically destroy ozone. The extent to which possible increases in surface emissions or transport of these VSLS bromocarbons to the stratosphere could counteract the effect of halogen reductions under the Montreal Protocol is an important policy question. Here by using a chemistry-climate model, UM-UKCA, we investigate the impact of a hypothetical increase in VSLS on ozone and how that impact depends on the background concentrations of chlorine and bromine. Our model experiments indicate that for a ~5 ppt increase in Bry from VSLS, the local ozone loss in the lowermost stratosphere of the Southern Hemisphere (SH) may reach up to 10% in the annual mean; the ozone loss in the Northern Hemisphere (NH) is smaller (4-6%). There is more ozone loss following an increase in VSLS burden under a high stratospheric chlorine background than under a low chlorine background indicating the importance of the inter-halogen reactions. For example, the rate of decline of the stratospheric ozone concentration as a function of Bry is higher by about 30-40% when stratospheric Cly is ~3 ppb (present day) compared with Cly of ~0.8 ppb (apre-industrial or projected future situation). Although bromine plays an important role in destroying ozone, inorganic chlorine is the dominant halogen compound. Even if bromine levels from natural VSLS were to increase significantly later this century, changes in the concentration of ozone will be dominated by the recovery of anthropogenic chlorine. Our calculation suggests that for a 5 ppt increase in Bry from VSLS, the Antarctic ozone hole recover date could be delayed by approximately 7 years.

  6. Diurnal variation of stratospheric chlorine monoxide: a critical test of chlorine chemistry in the ozone layer.

    PubMed

    Solomon, P M; de Zafra, R; Parrish, A; Barrett, J W

    1984-06-15

    This article reports measurements of the column density of stratospheric chlorine monoxide and presents a complete diurnal record of its variation (with 2-hour resolution) obtained from ground-based observations of a millimeter-wave spectral line at 278 gigahertz. Observations were carried out during October and December 1982 from Mauna Kea, Hawaii. The results reported here indicate that the mixing ratio and column density of chlorine monoxide above 30 kilometers during the daytime are approximately 20 percent lower than model predictions based on 2.1 parts per billion of total stratospheric chlorine. The observed day-to-night variation of chlorine monoxide is, however, in good agreement with recent model predictions, confirms the existence of a nighttime reservoir for chlorine, and verifies the predicted general rate of its storage and retrieval. From this evidence, it appears that the chlorine chemistry above 30 kilometers is close to being understood in current stratospheric models. Models based on this chemistry and measured reaction rates predict a reduction in the total stratospheric ozone content in the range of 3 to 5 percent in the final steady state for an otherwise unperturbed atmosphere, although the percentage decrease in the upper stratosphere is much higher.

  7. Diurnal variation of stratospheric chlorine monoxide: a critical test of chlorine chemistry in the ozone layer.

    PubMed

    Solomon, P M; de Zafra, R; Parrish, A; Barrett, J W

    1984-06-15

    This article reports measurements of the column density of stratospheric chlorine monoxide and presents a complete diurnal record of its variation (with 2-hour resolution) obtained from ground-based observations of a millimeter-wave spectral line at 278 gigahertz. Observations were carried out during October and December 1982 from Mauna Kea, Hawaii. The results reported here indicate that the mixing ratio and column density of chlorine monoxide above 30 kilometers during the daytime are approximately 20 percent lower than model predictions based on 2.1 parts per billion of total stratospheric chlorine. The observed day-to-night variation of chlorine monoxide is, however, in good agreement with recent model predictions, confirms the existence of a nighttime reservoir for chlorine, and verifies the predicted general rate of its storage and retrieval. From this evidence, it appears that the chlorine chemistry above 30 kilometers is close to being understood in current stratospheric models. Models based on this chemistry and measured reaction rates predict a reduction in the total stratospheric ozone content in the range of 3 to 5 percent in the final steady state for an otherwise unperturbed atmosphere, although the percentage decrease in the upper stratosphere is much higher. PMID:17819478

  8. SAGE (version 5.96) Ozone Trends in the Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Cunnold, D. M.; Wang, H. J.; Thomason, L. W.; Zawodny, J. M.; Logan, J. A.; Megretkaia, I. A.

    2002-01-01

    Ozone retrievals from Stratospheric Aerosol and Gas Experiment (SAGE) II version 5.96 (v5.96) below approx. 25 km altitude are discussed. This version of the algorithm includes improved constraints on the wavelength dependence of aerosol extinctions based on the ensemble of aerosol size distribution measurements. This results in a reduction of SAGE ozone errors in the 2 years after the Mount Pinatubo eruption. However, SAGE ozone concentrations are still approx. 10% larger than ozonesonde and Halogen Occultation Experiment (HALOE) measurements below 20 km altitude under nonvolcanic conditions (and by more than this in the tropics). The analysis by Steele and Turco suggests that the SAGE ozone overpredictions are in the wrong direction to be explained by aerosol extinction extrapolation errors. Moreover, preliminary SAGE 11 v6.0a retrievals suggest that they are partially accounted for by geometric difficulties at low altitudes in v5.96 and prior retrievals. SAGE ozone trends for the 1979-1996 and 1984-1996 periods are calculated and compared, and the sources of trend errors are discussed. These calculations are made after filtering out ozone data during periods of high, local aerosol extinctions. In the lower stratosphere, below approx. 28 km altitude, there is shown to be excellent agreement in the altitudinal structure of ozone decreases at 45 deg N between SAGE and ozonesondes with the largest decrease in both between 1979 and 1996 having occurred below 20 km altitude, amounting to 0.9 +/- 0.7% yr (2sigma) at 16 km altitude. However, in contrast to the fairly steady decreases at 45 deg N, both SAGE measurements and Lauder ozonesondes show ozone increases at 45 deg S over the period from the mid-1980s to 1996 of 0.2 +/- 0.5%/yr (2sigma) from 15 to 20 km altitude. The SAGE data suggest that this increase is a wintertime phenomenon which occurs in the 15-20 km height range. Changes in dynamics are suggested as the most likely cause of this increase. These

  9. Influence of Deep Convection On The Introduction of Ozone Into The Troposphere(stratosphere-troposphere Exchange).

    NASA Astrophysics Data System (ADS)

    Réchou, A.; Baray, J. L.; Baldy, S.

    Deep convection is very important in the tropics for its contribution to radiation, chemistry and transport. Baray et al.(1999) found a layer rich in ozone in the upper troposphere during the passage of the cyclone Marlene. Because of the season, this layer can't be explain by the inf luence of the biomass burning in Africa or in Madagascar. Neither, it can't be explain by the jet streak which was absent that day. Only the presence of the cyclone Marlene, which was far away from Reunion Island(55°E, 21°S), can explain this phenomenon. Downward motion from the stratosphere near the periphery of the cyclone can introduce such ozone levels. In analysing 8 years of data, we have found that this phenomenon is not isolated during the passage of cyclone. To advance our knowledge about the effects of the deep convection(not only the cyclones) on the injection of ozone into the troposphere, we will present results data from an experiment to be performed during February to March 2002. During this period, tropospheric and stratospheric Ozone and Rayleigh lidars will be operated. In conjunction with the lidar measurements, 10 PTU-O3 radiosondes will be lauched as the ITCZ approaches Reunion Island.The position of the ITCZ will be analysed by satellites NOAA - AVHRR data.

  10. Sensitivity of Polar Stratospheric Ozone Loss to Uncertainties in Chemical Reaction Kinetics

    NASA Technical Reports Server (NTRS)

    Kawa, S. Randolph; Stolarksi, Richard S.; Douglass, Anne R.; Newman, Paul A.

    2008-01-01

    Several recent observational and laboratory studies of processes involved in polar stratospheric ozone loss have prompted a reexamination of aspects of our understanding for this key indicator of global change. To a large extent, our confidence in understanding and projecting changes in polar and global ozone is based on our ability to simulate these processes in numerical models of chemistry and transport. The fidelity of the models is assessed in comparison with a wide range of observations. These models depend on laboratory-measured kinetic reaction rates and photolysis cross sections to simulate molecular interactions. A typical stratospheric chemistry mechanism has on the order of 50- 100 species undergoing over a hundred intermolecular reactions and several tens of photolysis reactions. The rates of all of these reactions are subject to uncertainty, some substantial. Given the complexity of the models, however, it is difficult to quantify uncertainties in many aspects of system. In this study we use a simple box-model scenario for Antarctic ozone to estimate the uncertainty in loss attributable to known reaction kinetic uncertainties. Following the method of earlier work, rates and uncertainties from the latest laboratory evaluations are applied in random combinations. We determine the key reactions and rates contributing the largest potential errors and compare the results to observations to evaluate which combinations are consistent with atmospheric data. Implications for our theoretical and practical understanding of polar ozone loss will be assessed.

  11. Stratospheric ozone destruction by aircraft-induced nitrogen oxides

    NASA Technical Reports Server (NTRS)

    Alyea, F. N.; Cunnold, D. M.; Prinn, R. G.

    1975-01-01

    The preliminary results from a three-dimensional dynamic-chemical model applied to the SST-NOx (NO + NO2) problem are reported. Simulations indicate that a depletion of about 12 per cent in total stratospheric O3 would be realized for a continuous NOx injection rate of 1.8 x 10 to the sixth power metric tons per year from a hypothetical fleet of SST's flying at an altitude of 20 km in the midlatitudes of the Northern Hemisphere. Sixteen per cent of the existing O3 would be destroyed on an annual basis. The model assumes a fleet of about 500 aircraft of the now-canceled American Boeing 2707 type; if only present Anglo-French and Russian SST models, which fly at lower, less harmful altitudes, are built, it will take a fleet of a few thousand such craft to attain an effective injection rate equal to the one above.

  12. Seasonal Variability of Middle Latitude Ozone in the Lowermost Stratosphere Derived from Probability Distribution Functions

    NASA Technical Reports Server (NTRS)

    Rood, Richard B.; Douglass, Anne R.; Cerniglia, Mark C.; Sparling, Lynn C.; Nielsen, J. Eric

    1999-01-01

    We present a study of the distribution of ozone in the lowermost stratosphere with the goal of characterizing the observed variability. The air in the lowermost stratosphere is divided into two population groups based on Ertel's potential vorticity at 300 hPa. High (low) potential vorticity at 300 hPa indicates that the tropopause is low (high), and the identification of these two groups is made to account for the dynamic variability. Conditional probability distribution functions are used to define the statistics of the ozone distribution from both observations and a three-dimensional model simulation using winds from the Goddard Earth Observing System Data Assimilation System for transport. Ozone data sets include ozonesonde observations from northern midlatitude stations (1991-96) and midlatitude observations made by the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite (UARS) (1994- 1998). The conditional probability distribution functions are calculated at a series of potential temperature surfaces spanning the domain from the midlatitude tropopause to surfaces higher than the mean tropical tropopause (approximately 380K). The probability distribution functions are similar for the two data sources, despite differences in horizontal and vertical resolution and spatial and temporal sampling. Comparisons with the model demonstrate that the model maintains a mix of air in the lowermost stratosphere similar to the observations. The model also simulates a realistic annual cycle. Results show that during summer, much of the observed variability is explained by the height of the tropopause. During the winter and spring, when the tropopause fluctuations are larger, less of the variability is explained by tropopause height. This suggests that more mixing occurs during these seasons. During all seasons, there is a transition zone near the tropopause that contains air characteristic of both the troposphere and the stratosphere. The

  13. Stratospheric Ozone and Temperature Changes in the Past: The Impact of Increased Concentrations of CFCs in Simulations with a Chemistry-Climate Model

    NASA Astrophysics Data System (ADS)

    Meul, S.; Oberländer, S.; Abalichin, J.; Kubin, A.; Langematz, U.

    2012-04-01

    Changes in stratospheric ozone between 1960 and the end of the 20th century are investigated analysing simulations with the Chemistry-Climate-Model (CCM) EMAC in FUB configuration (i.e. 39 layers with FUBRad parameterisation). In order to analyse the impact of increasing emissions of chlorofluorocarbons (CFCs) from 1960 to 2000 two sensitivity studies have been performed: a reference simulation with boundary conditions for the year 2000 and one analogue simulation but with CFC emissions reduced to 1960 levels. By comparing to a transient simulation (1960 to 2100) using the CCMVal SCN-B2d scenario it is possible to isolate the ozone changes that are caused by the CFC-increase only and separate the CFC-effect from other processes affecting ozone, e.g. climate change. By applying the method of Garny et al. (2011) the relative ozone changes arising from the CFC-modification can be attributed to changes in transport, chemical production and loss. Furthermore, it is analysed how the processes related to the CFC-increase contribute to the stratospheric cooling of up to 4K that is simulated by the SCN-B2d run between the 1960s and the 2000s in the upper stratosphere. The temperature change due to increased CFCs is caused by a reduced absorption of solar radiation by decreased ozone concentrations combined with the greenhouse gas (GHG) effect of the CFCs. In the upper stratosphere a cooling of up to 2.5K can be explained by the CFC-increase.

  14. 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.

  15. Stratospheric Ozone-induced Indirect Radiative Effects on Antarctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Hu, Y.; Xia, Y.; LIU, J.; Huang, Y.

    2015-12-01

    Recent studies demonstrated that the Antarctic Ozone Hole has important influences on Antarctic sea ice. While all these have focused on stratospheric ozone-induced dynamic effects on sea ice, here we show results that ozone-induced indirect radiative effects have important influences on Antarctic sea ice. Our simulations demonstrate that the recovery of the Antarctic Ozone Hole causes equatorward shift of clouds over the Southern Ocean. The cloud-band shift leads to reduction of downward infrared radiation, which causes surface cooling. On the other hand, it also causes increasing solar radiation on the surface. However, the increase in solar radiation is offset by surface reflection due to increasing sea ice. As a result solar radiation absorbed by the surface is reduced, which also causes surface cooling. Therefore, the overall ozone-induced cloud radiative effect is to cool the surface and causes expansion of sea ice around the Antarctic. As shown in previous studies, the cloud-band shift is associated with the equatorward shift of the westerly jet stream around the Antarctic. Our simulations also demonstrate increasing snow rate near the sea ice edge, which also contributes to Antarctic sea-ice expansion. The ozone-induced cloud radiative effect would mitigate Antarctic sea-ice melting due to greenhouse warming in the 21st century.

  16. The solar cycle variation of ozone in the stratosphere inferred from Nimbus 7 and NOAA 11 satellites

    SciTech Connect

    Chandra, S.; Mcpeters, R.D.

    1994-10-01

    The combined Nimbus 7 solar backscattered ultraviolet (SBUV) and NOAA 11 SBUV/2 ozone data, covering a period of more than a solar cycle (about 15 years), are used to study the UV response of ozone in the stratosphere. The study shows that about 2% change in total column ozone and about 5-7% change in ozone mixing ratio in the upper stratosphere (0.7 to 2 hPa) may be attributed to the change in the solar UV flux over a solar cycle. In the upper stratosphere, where photochemical processes are expected to play a major role, the measured solar cycle variation of ozone is significantly larger than inferred either from the photochemical models or from the ozone response to the 27-day solar UV modulation. For example, the observed solar cycle related change in ozone mixing ratio at 2 hPa is about 1% for 1% change in the solar UV flux near 200 nm. The inferred change in ozone from either the photochemical models or from the 27-day ozone-UV response is about a factor of 2-3 lower than this value.

  17. Two-dimensional simulation of Pinatubo aerosol and its effect on stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Tie, Xuexi; Brasseur, Guy P.; Briegleb, Bruce; Granier, Claire

    1994-01-01

    This paper presents time-dependent simulations of the response of the stratosphere to the injection into the atmosphere of massive amounts of sulfur during the eruption of Mt. Pinatubo (The Philippines) in June 1991. The study is based on a coupled two-dimensional chemical-dynamical-radiative model to which a microphysical model for sulfate aerosol formation and fate has been added. The study suggests that, during the first year (July 1991 to June 1992) following the volcanic eruption, the observed changes in the ozone amount integrated between 65 deg S and 65 deg N were caused primarily by changes in the meridional circulation (associated with heating by the volcanic cloud in the tropics) and in the photolysis rate of molecules such as ozone (associated with backscattering of light by the cloud). During the second year after the eruption, as the aerosol was dispersed at all latitudes and, in particular, reached the polar region, the largest contribution to ozone reduction resulted from the heterogeneous chemical conversion of N2O5 and ClONO2 on the surface of the aerosol particles. The conversion of the latter compound, and hence the magnitude of the calculated ozone depletion, is highly dependent on the temperature in the lower stratosphere. Despite the fact that the surface area provided by aerosol particles decreased during the second year following the eruption, the calculated ozone depletion remained significant because the conversion of N2O5 is insensitive to the aerosol surface area density for values larger than 1-10 sq microns/cu cm (depending on latitude). The predicted reduction in ozone at 20 km in March during the third year (July 1993 to June 1994) of the model integration is smaller by a factor of 2 than it was during the second year.

  18. Stratospheric Ozone Response in Experiments G3 and G4 of the Geoengineering Model Intercomparison Project (GeoMIP)

    NASA Technical Reports Server (NTRS)

    Pitari, Giovanni; Aquila, Valentina; Kravitz, Ben; Watanabe, Shingo; Tilmes, Simone; Mancini, Eva; DeLuca, Natalia; DiGenova, Glauco

    2013-01-01

    Geoengineering with stratospheric sulfate aerosols has been proposed as a means of temporarily cooling the planet, alleviating some of the side effects of anthropogenic CO2 emissions. However, one of the known side effects of stratospheric injections of sulfate aerosols is a decrease in stratospheric ozone. Here we show results from two general circulation models and two coupled chemistry climate models that have simulated stratospheric sulfate aerosol geoengineering as part of the Geoengineering Model Intercomparison Project (GeoMIP). Changes in photolysis rates and upwelling of ozone-poor air in the tropics reduce stratospheric ozone, suppression of the NOx cycle increases stratospheric ozone, and an increase in available surfaces for heterogeneous chemistry modulates reductions in ozone. On average, the models show a factor 20-40 increase of the sulfate aerosol surface area density (SAD) at 50 hPa in the tropics with respect to unperturbed background conditions and a factor 3-10 increase at mid-high latitudes. The net effect for a tropical injection rate of 5 Tg SO2 per year is a decrease in globally averaged ozone by 1.1-2.1 DU in the years 2040-2050 for three models which include heterogeneous chemistry on the sulfate aerosol surfaces. GISS-E2-R, a fully coupled general circulation model, performed simulations with no heterogeneous chemistry and a smaller aerosol size; it showed a decrease in ozone by 9.7 DU. After the year 2050, suppression of the NOx cycle becomes more important than destruction of ozone by ClOx, causing an increase in total stratospheric ozone. Contribution of ozone changes in this experiment to radiative forcing is 0.23 W m-2 in GISS-E2-R and less than 0.1 W m-2 in the other three models. Polar ozone depletion, due to enhanced formation of both sulfate aerosol SAD and polar stratospheric clouds, results in an average 5 percent increase in calculated surface UV-B.

  19. Effects of injected ice particles in the lower stratosphere on the Antarctic ozone hole

    NASA Astrophysics Data System (ADS)

    Nagase, H.; Kinnison, D. E.; Petersen, A. K.; Vitt, F.; Brasseur, G. P.

    2015-05-01

    The Antarctic ozone hole will continue to be observed in the next 35-50 years, although the emissions of chlorofluorocarbons (CFCs) have gradually been phased out during the last two decades. In this paper, we suggest a geo-engineering approach that will remove substantial amounts of hydrogen chloride (HCl) from the lower stratosphere in fall, and hence limit the formation of the Antarctic ozone hole in late winter and early spring. HCl will be removed by ice from the atmosphere at temperatures higher than the threshold under which polar stratospheric clouds (PSCs) are formed if sufficiently large amounts of ice are supplied to produce water saturation. A detailed chemical-climate numerical model is used to assess the expected efficiency of the proposed geo-engineering method, and specifically to calculate the removal of HCl by ice particles. The size of ice particles appears to be a key parameter: larger particles (with a radius between 10 and 100 µm) appear to be most efficient for removing HCl. Sensitivity studies lead to the conclusions that the ozone recovery is effective when ice particles are supplied during May and June in the latitude band ranging from 70°S to 90°S and in the altitude layer ranging from 10 to 26 km. It appears, therefore, that supplying ice particles to the Antarctic lower stratosphere could be effective in reducing the depth of the ozone hole. In addition, photodegradation of CFCs might be accelerated when ice is supplied due to enhanced vertical transport of this efficient greenhouse gas.

  20. Elevated Tropospheric Ozone Over the South Tropical Atlantic in January-February 1999: An Ozone Paradox Due to Interhemispheric Transport, Lightning, or Stratospheric Exchange?

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Doddridge, Bruce G.; Witte, Jacquelyn C.; Hudson, Robert D.; Luke, Winston T.; Johnson, James E.; Johnson, Bryan J.; Oltmans, Samuel J.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    On this first North American to southern African oceanographic cruise with ozonesonde launches (January and February 1999 on board the NOAA Research Vessel Ronald H Brown between Norfolk, VA, and Cape Town, South Africa) we found: (1) high ozone, CO, and aerosols off northern equatorial Africa from biomass burning, but even higher ozone concentrations off southern Africa which was not burning - an "ozone paradox"; (2) TOMS satellite evidence that south Atlantic elevated ozone in January-February 1999 was a regional feature similar in extent to the well-known September-October ozone maximum. Several mechanisms are considered to explain the "ozone paradox." Convection transporting air from the lower troposphere rich in ozone and/or ozone precursors to the upper troposphere through the ITCZ (intertropical Convergence Zone) may lead to cross-hemisphere transport of pollution. This is supported by trajectory linkage of lower-tropospheric ozone maxima with smoke seen by the TOMS satellite. Lightning-generated NO (nitric oxide) leading to ozone peaks of > 100 ppbv observed at 7-10 km altitude is another explanation. The TRMM (Tropical Rainfall Measuring Mission) Lightning Imaging Sounder shows many lightning flashes over southern Africa, which trajectories link to the high-ozone layers south of the ITCZ. The highest ozone peaks in the middle troposphere correspond to very low water vapor, which may point to photochemical destruction of ozone or subsidence from the upper troposphere which had interacted with stratospheric ozone.

  1. Internannual variability in chemistry and transport and its possible link to climate change: stratospheric ozone and water vapor

    NASA Astrophysics Data System (ADS)

    Weber, Mark; Burrows, John P.; Dhomse, Sandip

    Both transport via the Brewer-Dobson circulation and chemistry changes driven by stratospheric temperature variations contribute to the observed interannual variability in middle to high latitude total ozone as observed from 12 years of data from GOME and SCIAMACHY. The high correlation between the winter average eddy heat flux, which is a common measure of the strength of the Brewer-Dobson circulation and the accumulated winter transport, correlates well with spring total ozone, on one hand, and anti correlates with OClO observations, a measure of the chlorine activation (and cold temperatures) inside the polar vortex, on the other hand. Despite the interannual variability, it is evident that SH total ozone over the polar cap do not show yet a clear sign of recovery. This is not unexpected since the stratospheric chlorine load has just reached its maximum during this decade assuming a stratospheric age of 5-6 years over the polar region. Both transport and chemical ozone loss are closely tied and an important question is how they will evolve in a changing climate. A very sensitive indicator of circulation and transport changes is stratospheric water vapor near the tropical tropopause. Observations from HALOE and SAGE II indicated a drop in tropical lower stratospheric water vapor after year 2000 related to an enhancement in the winter BD circulation in both hemispheres. Extending satellite time series with water vapor observations from other available satellites, we investigate the question if the dry period in tropical stratospheric water vapor still persists.

  2. 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.

  3. Global OZone Chemistry And Related trace gas Data records for the Stratosphere (GOZCARDS)

    NASA Astrophysics Data System (ADS)

    Froidevaux, L.; Fuller, R.; Santee, M. L.; Schwartz, M. J.; Manney, G. L.; Livesey, N. J.; Anderson, J.; Wang, H.; Cunnold, D.; Bernath, P. F.; Walker, K. A.; Salawitch, R. J.; Canty, T. P.; Fiorucci, I.; Muscari, G.; Nedoluha, G. E.; Connor, B. J.; Pawson, S.

    2009-12-01

    The MEaSUREs GOZCARDS project will provide a commonly-formatted Earth system data record (ESDR) for stratospheric composition, of high relevance to the issue of ozone decline and recovery. The data records are drawn primarily from satellite-derived global stratospheric composition measurements from 1979 to the present, including on-going measurements from Aura MLS and ACE-FTS, as well as temperatures and potential vorticity from GSFC's meteorological reanalyses (GMAO MERRA). These data records will provide time series for stratospheric ozone (O3), hydrogen chloride (HCl), chlorine monoxide (ClO), nitric acid (HNO3), water vapor (H2O), nitrous oxide (N2O), nitrogen dioxide (NO2), nitrogen oxide (NO), methane (CH4), and hydrogen fluoride (HF). Additional "derived data records", using a constrained photochemical model, will be provided for active chlorine (ClOx) and odd nitrogen (NOx). The data are zonal means versus latitude on a common vertical grid, with time resolution of one month as a standard, and one day when possible (for emission measurements from the Microwave Limb Sounder on both UARS and Aura satellites). Data records binned in equivalent latitude and potential temperature will also be produced. We will provide both instrument-specific records and merged data records, with community access (website and data center) starting in 2010. We highlight some results and issues in this presentation.

  4. The Surface Climate Response to 11-Yr Solar Forcing During Northern Winter: Tests of the Stratospheric (UV-Ozone) Mechanism

    NASA Astrophysics Data System (ADS)

    Hood, Lon; Schimanke, Semjon; Spangehl, Thomas; Bal, Sourabh; Cubasch, Ulrich

    2014-05-01

    We have previously reported comparisons of observational estimates of the surface climate response to 11-yr solar forcing during northern winter with a series of GCM simulations that differed only in the assumed solar cycle variation of stratospheric ozone (Hood et al., J. of Climate, 2013). Here, we test further whether the most successful model simulation was primarily a consequence of stratospheric (solar UV-ozone) forcing by carrying out multiple linear regression analyses of model zonal wind and temperature data, and then comparing the results to similar analyses of observed zonal wind, temperature, and ozone data. It is found that the GCM simulation that produced a qualitative agreement with the observationally estimated surface climate response is characterized by an unusually strong zonal wind anomaly in the northern midlatitude upper stratosphere during early winter at solar maximum relative to solar minimum (about 5.5 m/s). The centennial period of this simulation that produced the best agreement yielded an even larger anomaly (7.5 m/s). This zonal wind anomaly is similar to (but smaller than) that derived from observations and is a consequence of the stronger latitudinal gradient of ozone and radiative heating in the upper stratosphere during early winter for this simulation. It propagates poleward and downward during the winter, perturbing tropospheric circulation and initiating ocean-atmosphere feedbacks that lead to the observed surface climate response. However, a major remaining uncertainty is the true magnitude of the solar forcing in the upper stratosphere that ultimately leads to the surface climate response. In addition to uncertainties in the solar spectral irradiance variation, there are also uncertainties in the true 11-year variation of ozone in the upper stratosphere that contribute indirectly to the radiative forcing. In particular, current observational evidence indicates that the 11-year variation of upper stratospheric ozone is

  5. Development of algorithms for using satellite meteorological data sets to study global transport of stratospheric aerosols and ozone

    NASA Technical Reports Server (NTRS)

    Want, P. H.; Deepak, A.

    1985-01-01

    The utilization of stratospheric aerosol and ozone measurements obtained from the NASA developed SAM II and SAGE satellite instruments were investigated for their global scale transports. The stratospheric aerosols showed that during the stratospheric warming of the winter 1978 to 1979, the distribution of the zonal mean aerosol extinction ratio in the northern high latitude exhibited distinct changes. Dynamic processes might have played an important role in maintenance role in maintenance of this zonal mean distribution. As to the stratospheric ozone, large poleward ozone transports are shown to occur in the altitude region from 24 km to 38 km near 55N during this warming. This altitude region is shown to be a transition region of the phase relationship between ozone and temperature waves from an in-phase one above 38 km. It is shown that the ozone solar heating in the upper stratosphere might lead to enhancement of the damping rate of the planetary waves due to infrared radiation alone in agreement with theoretical analyses and an earlier observational study.

  6. Comparing Simultaneous Stratospheric Aerosol and Ozone Lidar Measurements with SAGE 2 Data after the Mount Pinatubo Eruption

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Poole, L. R.; McCormick, M. P.; Veiga, R. E.; Wang, P.-H.; Rizi, V.; Masci, F.; DAltorio, A.; Visconti, G.

    1995-01-01

    Stratospheric aerosol and ozone profiles obtained simultaneously from the lidar station at the University of L'Aquila (42.35 deg N, 13.33 deg E, 683 m above sea level) during the first 6 months following the eruption of Mount Pinatubo are compared with corresponding nearby Stratospheric Aerosol and Gas Experiment (SAGE) 2 profiles. The agreement between the two data sets is found to be reasonably good. The temporal change of aerosol profiles obtained by both techniques showed the intrusion and growth of Pinatubo aerosols. In addition, ozone concentration profiles derived from an empirical time-series model based on SAGE 2 ozone data obtained before the Pinatubo eruption are compared with measured profiles. Good agreement is shown in the 1991 profiles, but ozone concentrations measured in January 1992 were reduced relative to time-series model estimates. Possible reasons for the differences between measured and model-based ozone profiles are discussed.

  7. Copernicus atmospheric service for stratospheric ozone: validation and intercomparison of four near real-time analyses, 2009-2012

    NASA Astrophysics Data System (ADS)

    Lefever, K.; van der A, R.; Baier, F.; Christophe, Y.; Errera, Q.; Eskes, H.; Flemming, J.; Inness, A.; Jones, L.; Lambert, J.-C.; Langerock, B.; Schultz, M. G.; Stein, O.; Wagner, A.; Chabrillat, S.

    2014-05-01

    This paper evaluates the performance of the stratospheric ozone analyses delivered in near real time by the MACC (Monitoring Atmospheric Composition and Climate) project during the 3 year period between September 2009 and September 2012. Ozone analyses produced by four different chemistry transport models and data assimilation techniques are examined: the ECMWF Integrated Forecast System (IFS) coupled to MOZART-3 (IFS-MOZART), the BIRA-IASB Belgian Assimilation System for Chemical ObsErvations (BASCOE), the DLR/RIU Synoptic Analysis of Chemical Constituents by Advanced Data Assimilation (SACADA), and the KNMI Data Assimilation Model based on Transport Model version 3 (TM3DAM). The assimilated satellite ozone retrievals differed for each system: SACADA and TM3DAM assimilated only total ozone observations, BASCOE assimilated profiles for ozone and some related species, while IFS-MOZART assimilated both types of ozone observations. The stratospheric ozone analyses are compared to independent ozone observations from ground-based instruments, ozone sondes and the ACE-FTS (Atmospheric Chemistry Experiment - Fourier Transform Spectrometer) satellite instrument. All analyses show total column values which are generally in good agreement with groundbased observations (biases <5%) and a realistic seasonal cycle. The only exceptions are found for BASCOE which systematically underestimates total ozone in the Tropics with about 7-10% at Chengkung (Taiwan, 23.1° N/121.365° E), resulting from the fact that BASCOE does not include any tropospheric processes, and for SACADA which overestimates total ozone in the absence of UV observations for the assimilation. Due to the large weight given to column observations in the assimilation procedure, IFS-MOZART is able to reproduce total column observations very well, but alternating positive and negative biases compared to ozonesonde and ACE-FTS satellite data are found in the vertical as well as an overestimation of 30 to 60% in the

  8. Trajectory model simulations of ozone (O3) and carbon monoxide (CO) in the lower stratosphere

    NASA Astrophysics Data System (ADS)

    Wang, T.; Randel, W. J.; Dessler, A. E.; Schoeberl, M. R.; Kinnison, D. E.

    2014-07-01

    A domain-filling, forward trajectory model originally developed for simulating stratospheric water vapor is used to simulate ozone (O3) and carbon monoxide (CO) in the lower stratosphere. Trajectories are initialized in the upper troposphere, and the circulation is based on reanalysis wind fields. In addition, chemical production and loss rates along trajectories are included using calculations from the Whole Atmosphere Community Climate Model (WACCM). The trajectory model results show good overall agreement with satellite observations from the Aura Microwave Limb Sounder (MLS) and the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) in terms of spatial structure and seasonal variability. The trajectory model results also agree well with the Eulerian WACCM simulations. Analysis of the simulated tracers shows that seasonal variations in tropical upwelling exerts strong influence on O3 and CO in the tropical lower stratosphere, and the coupled seasonal cycles provide a useful test of the transport simulations. Interannual variations in the tracers are also closely coupled to changes in upwelling, and the trajectory model can accurately capture and explain observed changes during 2005-2011. This demonstrates the importance of variability in tropical upwelling in forcing chemical changes in the tropical lower stratosphere.

  9. Stratospheric ozone in boreal fire plumes - the 2013 smoke season over central Europe

    NASA Astrophysics Data System (ADS)

    Trickl, T.; Vogelmann, H.; Flentje, H.; Ries, L.

    2015-08-01

    In July 2013 very strong boreal fire plumes were observed at the northern rim of the Alps by lidar and ceilometer measurements of aerosol, ozone and water vapour for about 3 weeks. In addition, some of the lower-tropospheric components of these layers were analysed at the Global Atmosphere Watch laboratory at the Schneefernerhaus high-altitude research station (2650 m a.s.l., located a few hundred metres south-west of the Zugspitze summit). The high amount of particles confirms our hypothesis that fires in the Arctic regions of North America lead to much stronger signatures in the central European atmosphere than the multitude of fires in the USA. This has been ascribed to the prevailing anticyclonic advection pattern during favourable periods and subsidence, in contrast to warm-conveyor-belt export, rainout and dilution frequently found for lower latitudes. A high number of the pronounced aerosol structures were positively correlated with elevated ozone. Chemical ozone formation in boreal fire plumes is known to be rather limited. Indeed, these air masses could be attributed to stratospheric air intrusions descending from remote high-latitude regions, obviously picking up the aerosol on their way across Canada. In one case, subsidence from the stratosphere over Siberia over as many as 15-20 days without increase in humidity was observed although a significant amount of Canadian smoke was trapped. These coherent air streams lead to rather straight and rapid transport of the particles to Europe.

  10. Reevaluation of Stratospheric Ozone Trends From SAGE II Data Using a Simultaneous Temporal and Spatial Analysis

    NASA Technical Reports Server (NTRS)

    Damadeo, R. P.; Zawodny, J. M.; Thomason, L. W.

    2014-01-01

    This paper details a new method of regression for sparsely sampled data sets for use with time-series analysis, in particular the Stratospheric Aerosol and Gas Experiment (SAGE) II ozone data set. Non-uniform spatial, temporal, and diurnal sampling present in the data set result in biased values for the long-term trend if not accounted for. This new method is performed close to the native resolution of measurements and is a simultaneous temporal and spatial analysis that accounts for potential diurnal ozone variation. Results show biases, introduced by the way data is prepared for use with traditional methods, can be as high as 10%. Derived long-term changes show declines in ozone similar to other studies but very different trends in the presumed recovery period, with differences up to 2% per decade. The regression model allows for a variable turnaround time and reveals a hemispheric asymmetry in derived trends in the middle to upper stratosphere. Similar methodology is also applied to SAGE II aerosol optical depth data to create a new volcanic proxy that covers the SAGE II mission period. Ultimately this technique may be extensible towards the inclusion of multiple data sets without the need for homogenization.

  11. 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.

  12. Research Spotlight: Ozone recovery and climate change will affect the atmosphere near Earth's surface

    NASA Astrophysics Data System (ADS)

    Kumar, Mohi; Tretkoff, Ernie

    Ozone in the stratosphere (˜10-50 kilometers in altitude) helps protect life on Earth from harmful solar ultraviolet radiation. But at the lower altitudes in the troposphere, (0-10 kilometers in altitude), ozone is a major constituent of smog and has detrimental health effects. The stratospheric ozone layer had been depleted but recently has started to recover due to efforts to limit emissions of ozone- depleting chemicals.

  13. Aircraft NO/x/ emissions and stratospheric ozone reductions - Another look

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Whitten, R. C.; Toon, O. B.; Inn, E. C. Y.; Hamill, P.

    1981-01-01

    New estimates for stratospheric ozone perturbations attributable to supersonic transport (SST) emissions are presented. First, a review is given of recent data pointing to lower OH concentrations below 30 km, as compared to the values predicted by photochemical models. The evidence for lower OH comes from a wide range of laboratory and atmospheric studies. The sensitivity of theoretical estimates of ozone change to OH abundances, and the coupling mechanisms between the O(x)-NO(x)-HO(x)-Cl(x) families which are responsible for the sensitivity, are discussed. Updated calculations for SST-induced ozone alterations are compared with older predictions. For example, assuming continuous aircraft injection of NO2 at 20 km at a rate of 1 x 10 to the 9th kg per year (globally), a 4% ozone decrease, is now calculated where earlier a 3% ozone increase was found. This large variance from previous forecasts suggests that new assessments of certain other polluting agents, particularly nitrogen fertilizers, are needed.

  14. Observed and Modeled HOCl Profiles in the Midlatitude Stratosphere: Implication for Ozone Loss

    NASA Technical Reports Server (NTRS)

    Kovalenko, L. J.; Jucks, K. W.; Salawitch, R. J.; Toon, G. C.; Blavier, J. F.; Johnson, D. G.; Kleinbohl, A.; Livesey, N. J .; Margitan, J. J.; Pickett, H. M.; Santee, M. L.; Sen, B.; Stachnik, R. A.; Waters, J. W.

    2007-01-01

    Vertical profiles of stratospheric HOCl calculated with a diurnal steady-state photochemical model that uses currently recommended reaction rates and photolysis cross sections underestimate observed profiles of HOCl obtained by two balloon-borne instruments, FIRS-2 (a far-infrared emission spectrometer) and MkIV (a mid-infrared, solar absorption spectrometer). Considerable uncertainty (a factor of two) persists in laboratory measurements of the rate constant (k(sub 1)) for the reaction ClO + HO2 yields HOCl + O2. Agreement between modeled and measured HOCl can be attained using a value of k(sub 1) from Stimpfle et al. (1979) that is about a factor-of-two faster than the currently recommended rate constant. Comparison of modeled and measured HOCl suggests that models using the currently recommended value for k(sub 1) may underestimate the role of the HOCl catalytic cycle for ozone depletion, important in the midlatitude lower stratosphere.

  15. Investigation of the effect of natural phenomena and industrial activity on stratospheric ozone trends. Final report, September 1993--June 1998

    SciTech Connect

    McElroy, M.B.; Schneider, H.R.

    1998-12-01

    The long term goal of this work is to separate the effects of natural variability and anthropogenic emissions on the chemical composition of the atmosphere. In particular, the authors are concerned with the variability of ozone in the stratosphere and the supply of ozone from the stratosphere to the upper troposphere. During the first phase of this project the authors developed an interactive two-dimensional (2D) model of the dynamics, radiation, and chemistry of the stratosphere. The most important features of the model are the use of the full primitive equations in two dimensions, small horizontal mixing in the tropical regions and small mechanical damping in the lower stratosphere. As a result, transport in the tropics and the mass exchange between the tropics and midlatitude are controlled advectively.

  16. Ozone and temperature decadal trends in the stratosphere, mesosphere and lower thermosphere, based on measurements from SABER on TIMED

    NASA Astrophysics Data System (ADS)

    Huang, F. T.; Mayr, H. G.; Russell, J. M., III; Mlynczak, M. G.

    2014-08-01

    We have derived ozone and temperature trends from years 2002 through 2012, from 20 to 100 km altitude, and 48° S to 48° N latitude, based on measurements from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED) satellite. For the first time, trends of ozone and temperature measured at the same times and locations are obtained, and their correlations should provide useful information about the relative importance of photochemistry versus dynamics over the longer term. We are not aware of comparable results covering this time period and spatial extent. For stratospheric ozone, until the late 1990s, previous studies found negative trends (decreasing amounts). In recent years, some empirical and modeling studies have shown the occurrence of a turnaround in the decreasing ozone, possibly beginning in the late 1990s, suggesting that the stratospheric ozone trend is leveling off or even turning positive. Our global results add more definitive evidence, expand the coverage, and show that at mid-latitudes (north and south) in the stratosphere, the ozone trends are indeed positive, with ozone having increased by a few percent from 2002 through 2012. However, in the tropics, we find negative ozone trends between 25 and 50 km. For stratospheric temperatures, the trends are mostly negatively correlated to the ozone trends. The temperature trends are positive in the tropics between 30 and 40 km, and between 20 and 25 km, at approximately 24° N and at 24° S latitude. The stratospheric temperature trends are otherwise mostly negative. In the mesosphere, the ozone trends are mostly flat, with suggestions of small positive trends at lower latitudes. The temperature trends in this region are mostly negative, showing decreases of up to ~ -3 K decade-1. In the lower thermosphere (between ~ 85 and 100 km), ozone and temperature trends are both negative. The ozone trend can

  17. Springtime high surface ozone events over the western United States: Quantifying the role of stratospheric intrusions

    NASA Astrophysics Data System (ADS)

    Fiore, A. M.; Lin, M.; Cooper, O. R.; Horowitz, L. W.; Naik, V.; Levy, H.; Langford, A. O.; Johnson, B. J.; Oltmans, S. J.; Senff, C. J.

    2011-12-01

    As the National Ambient Air Quality (NAAQS) standard for ozone (O_{3}) is lowered, it pushes closer to policy-relevant background levels (O_{3} concentrations that would exist in the absence of North American anthropogenic emissions), making attainment more difficult with local controls. We quantify the Asian and stratospheric components of this North American background, with a primary focus on the western United States. Prior work has identified this region as a hotspot for deep stratospheric intrusions in spring. We conduct global simulations at 200 km and 50 km horizontal resolution with the GFDL AM3 model, including a stratospheric O_{3} tracer and two sensitivity simulations with anthropogenic emissions from Asia and North America turned off. The model is evaluated with a suite of in situ and satellite measurements during the NOAA CalNex campaign (May-June 2010). The model reproduces the principle features in the observed surface to near tropopause distribution of O_{3} along the California coast, including its latitudinal variation and the development of regional high-O_{3} episodes. Four deep tropopause folds are diagnosed and we find that the remnants of these stratospheric intrusions are transported to the surface of Southern California and Western U.S. Rocky Mountains, contributing 10-30 ppbv positive anomalies relative to the simulated campaign mean stratospheric component in the model surface layer. We further examine the contribution of North American background, including its stratospheric and Asian components, to the entire distribution of observed MDA8 O_{3} at 12 high-elevation CASTNet sites in the Mountain West. We find that the stratospheric O_{3} tracer constitutes 50% of the North American background, and can enhance surface maximum daily 8-hour average (MDA8) O_{3} by 20 ppb when observed surface O_{3} is in the range of 60-80 ppbv. Our analysis highlights the potential for natural sources such as deep stratospheric intrusions to contribute

  18. Ground-based lidar measurements of stratospheric ozone. The NASA/GSFC stratospheric ozone lidar trailer experiment STROZ LITE

    NASA Technical Reports Server (NTRS)

    Mcgee, Thomas J.; Butler, James; Burris, John; Heaps, William S.

    1990-01-01

    The major research objective is the measurement of high precision vertical profiles of ozone between 20-40 kilometers. The precision is such that the instrument should be capable of detecting a small trend (on the order of less that 1 percent per year) over a 5-10 year period. Temperature was measured between 30 and 365 km. The Goddard Space Flight Center (GSFC) mobile lidar was installed at Table Mountain and a comparison between it and the permanent Jet Propulsion Laboratory (JPL) lidar was made over the course of about 3 weeks. The lidars agreed very well between 20 and 40 km, and under certain conditions up to 45-47 km. There were several anomalies that both lidars followed very well. Agreement with Rocket Ozonesonde (ROCOZ) and electrochemical concentration cell (ECC) sondes was also very good.

  19. The roles of dynamical and chemical processes in determining the stratospheric concentration of ozone in one-dimensional and two-dimensional models

    NASA Technical Reports Server (NTRS)

    Ko, Malcolm K. W.; Sze, Nien-Dak; Weisenstein, Debra K.

    1989-01-01

    The two-dimensional model of Ko et al. (1985) was used to calculate the stratospheric concentrations of ozone, to determine the principal modes of balance for different stratospheric regions. The results of this analysis show that the local concentration of ozone in different regions of stratosphere is determined by balances between different mechanisms. In the upper stratosphere, the ozone concentration is dominated by photochemical processes, whereas in the mid-lower stratosphere, the bulk of ozone appears to be controlled by an interaction between the transport and the photochemical processes. The results point to the limitations of one-dimensional models, which fail to properly account for the effect of transport in the lower stratosphere.

  20. Constructing Synoptic Maps of Stratospheric Column Ozone from HALOE, SAGE and Balloonsonde Data Using Potential Vorticity Isentropic Coordinate Transformations

    NASA Technical Reports Server (NTRS)

    Hollandsworth, Stacey M.; Schoeberl, Mark R.; Morris, Gary A.; Long, Craig; Zhou, Shuntai; Miller, Alvin J.

    1999-01-01

    In this study we utilize potential vorticity - isentropic (PVI) coordinate transformations as a means of combining ozone data from different sources to construct daily, synthetic three-dimensional ozone fields. This methodology has been used successfully to reconstruct ozone maps in particular regions from aircraft data over the period of the aircraft campaign. We expand this method to create high-resolution daily global maps of profile ozone data, particularly in the lower stratosphere, where high-resolution ozone data are sparse. Ozone climatologies in PVI-space are constructed from satellite-based SAGE II and UARS/HALOE data, both of which-use solar occultation techniques to make high vertical resolution ozone profile measurements, but with low spatial resolution. A climatology from ground-based balloonsonde data is also created. The climatologies are used to establish the relationship between ozone and dynamical variability, which is defined by the potential vorticity (in the form of equivalent latitude) and potential temperature fields. Once a PVI climatology has been created from data taken by one or more instruments, high-resolution daily profile ozone field estimates are constructed based solely on the PVI fields, which are available on a daily basis from NCEP analysis. These profile ozone maps could be used for a variety of applications, including use in conjunction with total ozone maps to create a daily tropospheric ozone product, as input to forecast models, or as a tool for validating independent ozone measurements when correlative data are not available. This technique is limited to regions where the ozone is a long-term tracer and the flow is adiabatic. We evaluate the internal consistency of the technique by transforming the ozone back to physical space and comparing to the original profiles. Biases in the long-term average of the differences are used to identify regions where the technique is consistently introducing errors. Initial results show

  1. Global 3-d modeling of atmospheric ozone in the free troposphere and the stratosphere with emphasis on midlatitude regions. Final report, July 1, 1994--June 30, 1997

    SciTech Connect

    Brasseur, G.; Erickson, D.; Tie, X.; Walter, S.

    1997-12-01

    The objective of this research is to use global chemical-transport models to study the chemical and dynamical processes that affect midlatitude stratospheric ozone and to quantify the budget of tropospheric ozone. Four models will be improved and used: (1) a new version of the two-dimensional chemical-radiative-dynamical model with microphysical process of sulfate aerosols and polar stratospheric clouds (PSCs), and heterogeneous conversions on the surfaces of sulfate aerosols and PSCs; (2) the stratospheric version of three-dimensional off-line chemical-transport model (STARS) with a relatively high horizontal resolution (2.8 degree in latitudes) with a microphysical formation of PSCs; (3) the tropospheric version of three-dimensional off-line chemical-transport model (MOZART) with details in the surface emissions and hydrocarbon reactions to estimate the tropospheric ozone budget and perturbations; (4) the intermediate model of the global and annual evolution of species (IMAGES) with a detailed chemical reactions but relatively lower resolutions. Model results will be compared with available data.

  2. Modeling the interaction of ozone with chloroform and bromoform under conditions close to stratospheric

    NASA Astrophysics Data System (ADS)

    Strokova, N. E.; Yagodovskaya, T. V.; Savilov, S. V.; Lukhovitskaya, E. E.; Vasil'ev, E. S.; Morozov, I. I.; Lunin, V. V.

    2013-02-01

    The reactions of ozone with chloroform and bromoform are studied using a flow gas discharge vacuum unit under conditions close to stratospheric (temperature range, 77-250 K; pressure, 10-3-0.1 Torr in the presence of nitrate ice). It is shown that the reaction with bromoform begins at 160 K; the reaction with chloroform, at 190 K. The reaction products are chlorine and bromine oxides of different composition, identified by low-temperature FTIR spectroscopy. The presence of nitrate ice raises the temperature of reaction onset to 210 K.

  3. Seasonal Variability of Middle Latitude Ozone in the Lowermost Stratosphere Derived from Probability Distribution Functions

    NASA Technical Reports Server (NTRS)

    Cerniglia, M. C.; Douglass, A. R.; Rood, R. B.; Sparling, L. C..; Nielsen, J. E.

    1999-01-01

    We present a study of the distribution of ozone in the lowermost stratosphere with the goal of understanding the relative contribution to the observations of air of either distinctly tropospheric or stratospheric origin. The air in the lowermost stratosphere is divided into two population groups based on Ertel's potential vorticity at 300 hPa. High [low] potential vorticity at 300 hPa suggests that the tropopause is low [high], and the identification of the two groups helps to account for dynamic variability. Conditional probability distribution functions are used to define the statistics of the mix from both observations and model simulations. Two data sources are chosen. First, several years of ozonesonde observations are used to exploit the high vertical resolution. Second, observations made by the Halogen Occultation Experiment [HALOE] on the Upper Atmosphere Research Satellite [UARS] are used to understand the impact on the results of the spatial limitations of the ozonesonde network. The conditional probability distribution functions are calculated at a series of potential temperature surfaces spanning the domain from the midlatitude tropopause to surfaces higher than the mean tropical tropopause [about 380K]. Despite the differences in spatial and temporal sampling, the probability distribution functions are similar for the two data sources. Comparisons with the model demonstrate that the model maintains a mix of air in the lowermost stratosphere similar to the observations. The model also simulates a realistic annual cycle. By using the model, possible mechanisms for the maintenance of mix of air in the lowermost stratosphere are revealed. The relevance of the results to the assessment of the environmental impact of aircraft effluence is discussed.

  4. Seasonal Variability of Middle Latitude Ozone in the Lowermost Stratosphere Derived from Probability Distribution Functions

    NASA Technical Reports Server (NTRS)

    Cerniglia, M. C.; Douglass, A. R.; Rood, R. B.; Sparling, L. C.; Nielsen, J. E.

    1999-01-01

    We present a study of the distribution of ozone in the lowermost stratosphere with the goal of understanding the relative contribution to the observations of air of either distinctly tropospheric or stratospheric origin. The air in the lowermost stratosphere is divided into two population groups based on Ertel's potential vorticity at 300 hPa. High [low] potential vorticity at 300 hPa suggests that the tropopause is low [high], and the identification of the two groups helps to account for dynamic variability. Conditional probability distribution functions are used to define the statistics of the mix from both observations and model simulations. Two data sources are chosen. First, several years of ozonesonde observations are used to exploit the high vertical resolution. Second, observations made by the Halogen Occultation Experiment [HALOE) on the Upper Atmosphere Research Satellite [UARS] are used to understand the impact on the results of the spatial limitations of the ozonesonde network. The conditional probability distribution functions are calculated at a series of potential temperature surfaces spanning the domain from the midlatitude tropopause to surfaces higher than the mean tropical tropopause [approximately 380K]. Despite the differences in spatial and temporal sampling, the probability distribution functions are similar for the two data sources. Comparisons with the model demonstrate that the model maintains a mix of air in the lowermost stratosphere similar to the observations. The model also simulates a realistic annual cycle. By using the model, possible mechanisms for the maintenance of mix of air in the lowermost stratosphere are revealed. The relevance of the results to the assessment of the environmental impact of aircraft effluence is discussed.

  5. Measured and modeled HOCl profiles in the mid-latitude stratosphere : implication for ozone loss

    NASA Technical Reports Server (NTRS)

    Kovalenko, L. J.; Salawitch, R. J.; Blavier, J. -F.; Sen, B.; Toon, G. C.; Jucks, K. W.; Johnson, D. G.; Stachnik, R. A.; Margitan, J. J.

    2004-01-01

    The HOCl catalytic cycle is an efficient ozone loss mechanism in the lower mid-latitude stratosphere. We use a diurnal steady-state photochemical model to calculate profiles of HOCl for conditions encountered by a number of high-altitude balloon flights. To assess how well this model represents ozone loss by the HOCl cycle, we compare our calculations of HOCl and its precursors Cl0 and HO2 with measurements obtained by an FTIR solar absorption spectrometer (MkIV), a far-infrared emission spectrometer (FIRS-2), and a submillimetenvave limb sounder (SLS). We then evaluate these comparisons in light of a number of recent laboratory studies of the main formation mechanism of HOCl, the reaction of Cl0 + HO2. Those studies measured both the reaction rate constant and the quantum yield for a second product pathway, formation of HCl.

  6. Model/data comparisons of ozone in the upper stratosphere and mesosphere

    NASA Technical Reports Server (NTRS)

    Siskind, David E.; Remsberg, Ellis E.; Eckman, Richard S.; Connor, Brian J.; Tsou, J. J.; Parrish, Alan

    1994-01-01

    We compare ground-based microwave observations of ozone in the upper stratosphere and mesosphere with daytime observations made from the SME (Solar Mesosphere Explorer) satellite, with nighttime data from the LIMS instrument, and with a diurnal photochemical model. The results suggest that the data are all in reasonable agreement and that the model-data discrepancy is much less than previously thought, particularly in the mesosphere. This appears to be due to the fact that the latest data are lower than earlier reports and the updated model predicts more ozone than older versions. The model and the data agree to within a factor of 1.5 at all altitudes and typically are within 20 percent.

  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. 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.

  9. Stratospheric ozone depletion and the risk of non-melanoma skin cancer in a British population.

    PubMed

    Diffey, B L

    1992-12-01

    Quantitative estimation of the increased risk of non-melanoma skin cancer (NMSC) in British people that may result from depletion of the stratospheric ozone layer is given for the present generation of British people. For adults alive today continuing ozone depletion at current rates is predicted to result in a relatively small additional lifetime risk (< 5%) of NMSC, assuming no changes in climate, time spent outdoors, behaviour or clothing habits. The lifetime risk incurred by today's children, however, is 10%-15% greater than expected in the absence of ozone depletion. However, if the production and use of substances which deplete ozone are reduced, as expected under the current provisions of the Montreal Protocol, the increased lifetime risk of skin cancer is likely to be less than this estimate. These predicted increases in risk, resulting from greater solar ultraviolet exposure, can be offset by adopting changes to behaviour during the summer months which may involve spending less time outdoors, wearing appropriate clothing including wide-brimmed hats, applying topical sunscreens, or a combination of these.

  10. Sensitivity of Polar Stratospheric Ozone Loss to Uncertainties in Chemical Reaction Kinetics

    NASA Technical Reports Server (NTRS)

    Kawa, S. Randolph; Stolarski, Richard S.; Douglass, Anne R.; Newman, Paul A.

    2008-01-01

    Several recent observational and laboratory studies of processes involved in polar stratospheric ozone loss have prompted a reexamination of aspect of out understanding for this key indicator of global change. To a large extent, our confidence in understanding and projecting changes in polar and global ozone is based on our ability to to simulate these process in numerical models of chemistry and transport. These models depend on laboratory-measured kinetic reaction rates and photlysis cross section to simulate molecular interactions. In this study we use a simple box-model scenario for Antarctic ozone to estimate the uncertainty in loss attributable to known reaction kinetic uncertainties. Following the method of earlier work, rates and uncertainties from the latest laboratory evaluation are applied in random combinations. We determine the key reaction and rates contributing the largest potential errors and compare the results to observations to evaluate which combinations are consistent with atmospheric data. Implications for our theoretical and practical understanding of polar ozone loss will be assessed.

  11. Stratospheric Ozone Variations Caused by Solar Proton Events between 1963 and 2005

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Fleming, Eric L.

    2006-01-01

    Solar proton fluxes have been measured by satellites for over forty years (1963-2005). Several satellites, including the NASA Interplanetary Monitoring Platforms (1963-1993) and the NOAA Geostationary Operational Environmental Satellites (1994-2005), have been used to compile this long-term dataset. Some solar eruptions lead to solar proton events (SPEs) at the Earth, which typically last a few days. High energy solar protons associated with SPEs precipitate on the Earth's atmosphere and cause increases in odd hydrogen (HOx) and odd nitrogen (NOy) in the polar cap regions (greater than 60 degrees geomagnetic). The enhanced HOx leads to short-lived ozone depletion (days) due to the short lifetime of HOx constituents. The enhanced NOy leads to long-lived ozone changes because of the long lifetime of the NOy family in the stratosphere and lower mesosphere. Very large SPEs occurred in 1972, 1989, 2000, 2001, and 2003 and were predicted to cause maximum total ozone depletions of 1-3%, which lasted for several months to years past the events. These long-term ozone changes caused by SPES are discussed.

  12. Stratospheric chemistry

    SciTech Connect

    Brune, W.H. )

    1991-01-01

    Advances in stratospheric chemistry made by investigators in the United States from 1987 to 1990 are reviewed. Subject areas under consideration include photochemistry of the polar stratosphere, photochemistry of the global stratosphere, and assessments of inadvertent modification of the stratosphere by anthropogenic activity. Particular attention is given to early observations and theories, gas phase chemistry, Antarctic observations, Arctic observations, odd-oxygen, odd-hydrogen, odd-nitrogen, halogens, aerosols, modeling of stratospheric ozone, and reactive nitrogen effects.

  13. The discrepancy between stratospheric ozone profiles from balloon soundings and from other techniques: A possible explanation

    NASA Technical Reports Server (NTRS)

    Demuer, Dirk; Debacker, Hugo

    1994-01-01

    Regular balloon ozone soundings with electrochemical sondes have been performed at Uccle since 1969. More than 450 ozone soundings between 1985 and 1989 were used to calculate the altitudes Zs from the VIZ radiosonde data and the altitudes Zr deduced from the tracking of the balloon train with a primary wind-finding radar. The values of Zs at fixed times appeared to be systematically too low as compared to Zr. The differences Zr-Zs increase with altitude; at 30 km the annual mean values of Zr-Zs (plus or minus standard deviation) vary between 590 plus or minus 910 m and 1410 plus or minus 1160 m, according to the pressure calibration of different manufacturing series of radiosondes. From these results it is found that around the 30 km level the ozone concentrations calculated from soundings with VIZ sondes are too low by 7.5 to 14 percent, depending upon the manufacturing series of radiosondes. At least part of the discrepancy which has often been found between ozone profiles from balloon soundings and from other techniques such as rocket observations or Umkehr measurements may be explained by this effect. An altitude correction would have important consequences as to the climatology of ozone in the middle stratosphere as adopted at the moment. About half of the day-to-day variability of ozone observed from soundings with VIZ radiosondes above the 30 km level, is induced by the variability of Zr-Zs. The agreement between altitudes calculated from radar data and Vaisala radiosondes is much better; from 34 comparative soundings a mean difference (plus or minus standard deviation) of about -300 plus/minus 180 m was found at 30 km.

  14. 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

  15. 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

  16. 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

  17. Stratospheric ozone, global warming, and the principle of unintended consequences--an ongoing science and policy success story.

    PubMed

    Andersen, Stephen O; Halberstadt, Marcel L; Borgford-Parnell, Nathan

    2013-06-01

    In 1974, Mario Molina and F. Sherwood Rowland warned that chlorofluorocarbons (CFCs) could destroy the stratospheric ozone layer that protects Earth from harmful ultraviolet radiation. In the decade after scientists documented the buildup and long lifetime of CFCs in the atmosphere; found the proof that CFCs chemically decomposed in the stratosphere and catalyzed the depletion of ozone; quantified the adverse effects; and motivated the public and policymakers to take action. In 1987, 24 nations plus the European Community signed the Montreal Protocol. Today, 25 years after the Montreal Protocol was agreed, every United Nations state is a party (universal ratification of 196 governments); all parties are in compliance with the stringent controls; 98% of almost 100 ozone-depleting chemicals have been phased out worldwide; and the stratospheric ozone layer is on its way to recovery by 2065. A growing coalition of nations supports using the Montreal Protocol to phase down hydrofluorocarbons, which are ozone safe but potent greenhouse gases. Without rigorous science and international consensus, emissions of CFCs and related ozone-depleting substances (ODSs) could have destroyed up to two-thirds of the ozone layer by 2065, increasing the risk of causing millions of cancer cases and the potential loss of half of global agricultural production. Furthermore, because most, ODSs are also greenhouse gases, CFCs and related ODSs could have had the effect of the equivalent of 24-76 gigatons per year of carbon dioxide. This critical review describes the history of the science of stratospheric ozone depletion, summarizes the evolution of control measures and compliance under the Montreal Protocol and national legislation, presents a review of six separate transformations over the last 100 years in refrigeration and air conditioning (A/C) technology, and illustrates government-industry cooperation in continually improving the environmental performance of motor vehicle A/C.

  18. Stratospheric ozone, global warming, and the principle of unintended consequences--an ongoing science and policy success story.

    PubMed

    Andersen, Stephen O; Halberstadt, Marcel L; Borgford-Parnell, Nathan

    2013-06-01

    In 1974, Mario Molina and F. Sherwood Rowland warned that chlorofluorocarbons (CFCs) could destroy the stratospheric ozone layer that protects Earth from harmful ultraviolet radiation. In the decade after scientists documented the buildup and long lifetime of CFCs in the atmosphere; found the proof that CFCs chemically decomposed in the stratosphere and catalyzed the depletion of ozone; quantified the adverse effects; and motivated the public and policymakers to take action. In 1987, 24 nations plus the European Community signed the Montreal Protocol. Today, 25 years after the Montreal Protocol was agreed, every United Nations state is a party (universal ratification of 196 governments); all parties are in compliance with the stringent controls; 98% of almost 100 ozone-depleting chemicals have been phased out worldwide; and the stratospheric ozone layer is on its way to recovery by 2065. A growing coalition of nations supports using the Montreal Protocol to phase down hydrofluorocarbons, which are ozone safe but potent greenhouse gases. Without rigorous science and international consensus, emissions of CFCs and related ozone-depleting substances (ODSs) could have destroyed up to two-thirds of the ozone layer by 2065, increasing the risk of causing millions of cancer cases and the potential loss of half of global agricultural production. Furthermore, because most, ODSs are also greenhouse gases, CFCs and related ODSs could have had the effect of the equivalent of 24-76 gigatons per year of carbon dioxide. This critical review describes the history of the science of stratospheric ozone depletion, summarizes the evolution of control measures and compliance under the Montreal Protocol and national legislation, presents a review of six separate transformations over the last 100 years in refrigeration and air conditioning (A/C) technology, and illustrates government-industry cooperation in continually improving the environmental performance of motor vehicle A/C. PMID

  19. The diurnal variation in stratospheric ozone from the MACC reanalysis, the ERA-Interim reanalysis, WACCM and Earth observation data: characteristics and intercomparison

    NASA Astrophysics Data System (ADS)

    Schanz, A.; Hocke, K.; Kämpfer, N.; Chabrillat, S.; Inness, A.; Palm, M.; Notholt, J.; Boyd, I.; Parrish, A.; Kasai, Y.

    2014-12-01

    In this study we compare the diurnal variation in stratospheric ozone derived from free-running simulations of the Whole Atmosphere Community Climate Model (WACCM) and from reanalysis data of the atmospheric service MACC (Monitoring Atmospheric Composition and Climate) which both use a similar stratospheric chemistry module. We find good agreement between WACCM and the MACC reanalysis for the diurnal ozone variation in the high-latitude summer stratosphere based on photochemistry. In addition, we consult the ozone data product of the ERA-Interim reanalysis. The ERA-Interim reanalysis ozone system with its long-term ozone parametrization can not capture these diurnal variations in the upper stratosphere that are due to photochemistry. The good dynamics representations, however, reflects well dynamically induced ozone variations in the lower stratosphere. For the high-latitude winter stratosphere we describe a novel feature of diurnal variation in ozone where changes of up to 46.6% (3.3 ppmv) occur in monthly mean data. For this effect good agreement between the ERA-Interim reanalysis and the MACC reanalysis suggest quite similar diurnal advection processes of ozone. The free-running WACCM model seriously underestimates the role of diurnal advection processes at the polar vortex at the two tested resolutions. The intercomparison of the MACC reanalysis and the ERA-Interim reanalysis demonstrates how global reanalyses can benefit from a chemical representation held by a chemical transport model. The MACC reanalysis provides an unprecedented description of the dynamics and photochemistry of the diurnal variation of stratospheric ozone which is of high interest for ozone trend analysis and research on atmospheric tides. We confirm the diurnal variation in ozone at 5 hPa by observations of the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) experiment and selected sites of the Network for Detection of Atmospheric Composition Change (NDACC). The latter

  20. Observation-based assessment of stratospheric fractional release, lifetimes, and ozone depletion potentials of ten important source gases

    NASA Astrophysics Data System (ADS)

    Laube, J. C.; Keil, A.; Bönisch, H.; Engel, A.; Röckmann, T.; Volk, C. M.; Sturges, W. T.

    2013-03-01

    Estimates of the recovery time of stratospheric ozone heavily rely on the exact knowledge of the processes that lead to the decomposition of the relevant halogenated source gases. Crucial parameters in this context are fractional release factors (FRFs) as well as stratospheric lifetimes and ozone depletion potentials (ODPs). We here present data from the analysis of air samples collected between 2009 and 2011 on board research aircraft flying in the mid- and high-latitude stratosphere and infer the above-mentioned parameters for ten major source gases: CFCl3 (CFC-11), CF2Cl2 (CFC-12), CF2ClCFCl2 (CFC-113), CCl4 (carbon tetrachloride), CH3CCl3 (methyl chloroform), CHF2Cl (HCFC-22), CH3CFCl2 (HCFC-141b), CH3CF2Cl (HCFC-142b), CF2ClBr (H-1211), and CF3Br (H-1301). The inferred correlations of their FRFs with mean ages of air reveal less decomposition as compared to previous studies for most compounds. When using the calculated set of FRFs to infer equivalent stratospheric chlorine, we find a reduction of more than 20% as compared to the values inferred in the most recent Scientific Assessment of Ozone Depletion by the World Meteorological Organisation (WMO, 2011). We also note that FRFs and their correlations with mean age are not generally time-independent as often assumed. The stratospheric lifetimes were calculated relative to that of CFC-11. Within our uncertainties the ratios between stratospheric lifetimes inferred here agree with the values in recent WMO reports except for CFC-11, CFC-12 and CH3CCl3. Finally, we calculate lower ODPs than recommended by WMO for six out of ten compounds, with changes most pronounced for the three HCFCs. Collectively these newly calculated values may have important implications for the severity and recovery time of stratospheric ozone loss.

  1. Observation-based assessment of stratospheric fractional release, lifetimes, and Ozone Depletion Potentials of ten important source gases

    NASA Astrophysics Data System (ADS)

    Laube, J. C.; Keil, A.; Bönisch, H.; Engel, A.; Röckmann, T.; Volk, C. M.; Sturges, W. T.

    2012-10-01

    Estimates of the recovery time of stratospheric ozone heavily rely on the exact knowledge of the processes that lead to the decomposition of the relevant halogenated source gases. Crucial parameters in this context are Fractional Release Factors (FRFs) as well as stratospheric lifetimes and Ozone Depletion Potentials (ODPs). We here present data from the analysis of air samples collected between 2009 and 2011 on board research aircraft flying in the mid- and high latitudinal stratosphere and infer the above-mentioned parameters for ten major source gases:CFCl3 (CFC-11), CF2Cl2 (CFC-12), CF2ClCFCl2(CFC-113), CCl4 (carbon tetrachloride),CH3CCl3 (methyl chloroform), CHF2Cl (HCFC-22), CH3CFCl2 (HCFC-141b), CH3CF2Cl (HCFC-142b), CF2ClBr (H-1211), and CF3Br (H-1301). The inferred correlations of their FRFs with mean ages of air reveal less decomposition as compared to previous studies for most compounds. When using the calculated set of FRFs to infer equivalent stratospheric chlorine we find a reduction of more than 20% as compared to the values inferred in the most recent Scientific Assessment of Ozone Depletion by the World Meteorological Organisation (WMO, 2011). We also note that FRFs and their correlations with mean age are not generally time-independent as often assumed. The stratospheric lifetimes were calculated relative to that of CFC-11. Within our uncertainties the inferred ratios between lifetimes agree with those between stratospheric lifetimes from recent WMO reports except for CFC-11, CFC-12 and CH3CCl3. Finally we calculate lower ODPs than WMO for six out of ten compounds with changes most pronounced for the three HCFCs. Collectively these newly calculated values may have important implications for the severity and recovery time of stratospheric ozone loss.

  2. Satellite Measured Solar Protons from 1963-1993 and Their Influence on Ozone in a Changing Stratosphere

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Fleming, Eric L.; Vitt, Francis M.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The fluxes of solar protons have been measured by a series of Interplanetary Monitoring Platform (IMP) satellites since 1963. Eight IMP satellites have been launched since 1963 providing excellent coverage of solar protons with energies from a few MeV to several hundred MeV. IMP 8, launched in October 1973, continues to provide proton measurements, twenty-six and a half (26 1/2) years after launch. These high energy solar protons rain down on the earth's polar atmosphere sporadically, primarily during solar proton events (SPEs) which typically last a few days. Solar protons with energies of 30 MeV or greater are capable of reaching the stratosphere and causing increases in odd nitrogen (NO(y)) constituents at polar latitudes ($>$ 60 degrees geomagnetic) which last for several months to years past the events. These enhanced NO(y) species can lead to significant upper stratospheric ozone depletions $ greater than $10\\% during the gigantic SPEs that occurred in August 1972 and October 1989. We studied the effects of SPEs on the stratosphere from 1963 to the mid 1990s. During this time period, the stratospheric chlorine levels changed from relatively small in 1963 ($\\sim$ 1 ppbv) to fairly substantial amounts in the mid-1990s ($\\sim$ 3.3 ppbv). Our recently improved two-dimensional chemistry and transport atmospheric model was used to compute the effects of SPEs in this changing stratosphere. The long-lived SPE-produced NO(y) constituents were transported to lower stratospheric levels during winter after the events and caused impacts in the middle and lower stratosphere. Generally, the SPEs resulted in a decrease in ozone. However, during periods of high halogen loading these impacts resulted in interference with the chlorine and bromine loss cycles for ozone destruction. This interference actually led to a predicted total ozone increase that was especially notable in the time period 1992-4, a few years after the October 1989 SPE.

  3. Trajectory model simulations of ozone and carbon monoxide in the Upper Troposphere and Lower Stratosphere (UTLS)

    NASA Astrophysics Data System (ADS)

    Wang, T.; Randel, W. J.; Dessler, A. E.; Schoeberl, M. R.; Kinnison, D. E.

    2014-03-01

    A domain-filling, forward trajectory model originally developed for simulating stratospheric water vapor is used to simulate ozone (O3) and carbon monoxide (CO) in the upper troposphere and lower stratosphere (UTLS). Trajectories are initialized in the upper troposphere, and the circulation is based on reanalysis wind fields. In addition, chemical production and loss rates along trajectories are included using calculations from the Whole Atmosphere Community Climate Model (WACCM). The trajectory model results show good overall agreement with satellite observations from the Aura Microwave Limb Sounder (MLS) and the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) in terms of spatial structure and seasonal variability. The trajectory model results also agree well with the Eulerian WACCM simulations. Analysis of the simulated tracers shows that seasonal variations in tropical upwelling exerts strong influence on O3 and CO in the tropical lower stratosphere, and the coupled seasonal cycles provide a useful test of the transport simulations. Interannual variations in the tracers are also closely coupled to changes in upwelling, and the trajectory model can accurately capture and explain observed changes during 2005-2011. This demonstrates the importance of variability in tropical upwelling in forcing chemical changes in the tropical UTLS.

  4. Photochemical modeling of the Antarctic stratosphere: Observational constraints from the airborne Antarctic ozone experiment and implications for ozone behavior

    NASA Technical Reports Server (NTRS)

    Rodriguez, Jose M.; Sze, Nien-Dak; Ko, Malcolm K. W.

    1988-01-01

    The rapid decrease in O3 column densities observed during Antarctic spring has been attributed to several chemical mechanisms involving nitrogen, bromine, or chlorine species, to dynamical mechanisms, or to a combination of the above. Chlorine-related theories, in particular, predict greatly elevated concentrations of ClO and OClO and suppressed abundances of NO2 below 22 km. The heterogeneous reactions and phase transitions proposed by these theories could also impact the concentrations of HCl, ClNO3 and HNO3 in this region. Observations of the above species have been carried out from the ground by the National Ozone Expedition (NOZE-I, 1986, and NOZE-II, 1987), and from aircrafts by the Airborne Antarctic Ozone Experiment (AAOE) during the austral spring of 1987. Observations of aerosol concentrations, size distribution and backscattering ratio from AAOE, and of aerosol extinction coefficients from the SAM-II satellite can also be used to deduce the altitude and temporal behavior of surfaces which catalyze heterogeneous mechanisms. All these observations provide important constraints on the photochemical processes suggested for the spring Antarctic stratosphere. Results are presented for the concentrations and time development of key trace gases in the Antarctic stratosphere, utilizing the AER photochemical model. This model includes complete gas-phase photochemistry, as well as heterogeneous reactions. Heterogeneous chemistry is parameterized in terms of surface concentrations of aerosols, collision frequencies between gas molecules and aerosol surfaces, concentrations of HCl/H2O in the frozen particles, and probability of reaction per collision (gamma). Values of gamma are taken from the latest laboratory measurements. The heterogeneous chemistry and phase transitions are assumed to occur between 12 and 22 km. The behavior of trace species at higher altitudes is calculated by the AER 2-D model without heterogeneous chemistry. Calculations are performed for

  5. Ozone Destruction in the Upper Troposphere/Lower Stratosphere from Short-Lived Halogens and Climate Impacts

    NASA Astrophysics Data System (ADS)

    Hossaini, Ryan; Chipperfield, Martyn; Montzka, Stephen; Rap, Alex; Dhomse, Sandip; Feng, Wuhu

    2014-05-01

    Halogens released from very short-lived substances (VSLS) can deplete ozone in the upper-troposphere and lower stratosphere where the perturbation can exert a large climate impact. In addition to the known ozone loss from natural biogenic bromine VSLS, such as bromoform (CHBr3), using a global atmospheric model we show that anthropogenic chlorine VSLS such as dichloromethane (CH2Cl2) - not regulated by the Montreal Protocol - also contribute. Although this impact is small compared to bromine VSLS at present, CH2Cl2 has industrial sources and observations show its atmospheric loading is increasing rapidly. We estimate a significant radiative effect of the bromine and chlorine VSLS-driven lower stratospheric ozone destruction of -0.11 Wm-2. The largest impact comes from ozone loss at high latitudes, where column ozone decreases due to VSLS are up to 6%. The trend in anthropogenic chlorine VSLS could cause a significant radiative forcing, especially if augmented by any trend in natural bromine VSLS. We also used the model to study the impact of iodine-containing VSLS such as methyl iodide (CH3I). Of the three halogens iodine has the largest leverage to destroy lower stratospheric ozone, but current limits based on IO observations indicate only a minor impact at present.

  6. The quasi-biennial oscillation of ozone in the tropical middle stratosphere - A one-dimensional model

    NASA Technical Reports Server (NTRS)

    Ling, Xiu-De; London, Julius

    1986-01-01

    A one-dimensional model of the quasi-biennial oscillation (QBO) of ozone in the tropical middle stratosphere is derived based on assumed (observed) zonal wind QBO in a coupled dynamic, radiative/photochemical system. It is found that the derived vertical variation of the ozone QBO amplitude has two maxima, one at 32 km and the other at 22 km, and a minimum at 28 km. These are in qualitative agreement with observations. In the height interval 30-35 km, the ozone QBO is closely related to temperature dependent photochemistry, and the ozone and temperature variations are out of phase. Below 28 km, where vertical ozone and thermal transports are important, ozone and temperature oscillations are in phase, but both are approximately 270 deg out of phase with the vertical wind variation.

  7. Remote sensing of the stratospheric ozone profile using a tunable sideband CO(2) laser heterodyne spectroscopy

    NASA Astrophysics Data System (ADS)

    Shahnazi, Kambiz

    1997-12-01

    In this work, a systematic approach for remote sensing of stratospheric ozone was developed. Preliminary studies of the line shape, Doppler width, number density, and its theoretical location from Hitran data base using direct detection were made. Seven absorption lines were studied and recorded. These lines were only a few wavenumbers away from various CO2 vibrational rotational lines. This extracted information allowed us to choose a few particular lines in our stratospheric measurements. The sweeping of these lines was done by an electro-optic phase modulator capable of tuning from 8-18 GHz with input electrical power of about 10 Watts, and optical power of 300 mW. The uniqueness of this experiment is its sweeping capability with resolution limited by the laser line width (≈100 KHz) and synthesizer tuning. The resolution of our measurements was 5 MHz (0.000016 cm-1) with signal to noise ratio of 100. By using the heterodyne technique in the laboratory, an absorption line of ozone was obtained. The measured ozone line was at 14.65 GHz away from CO2 carrier at 9p22 transition line with signal to noise ratio of 100:1 and with resolution of about 5 MHz. The next objective was to obtain field data on stratospheric ozone. The field measurements were obtained on February 12 and February 23 1997 between 9:00 A.M and 11:30 A.M. The angle of the sun from the horizon was about 40-45 degrees. With a modified sun tracking system, a window of about 3-5 minutes per scan was obtained. A total of three lines were observed and recorded using this heterodyne technique. Information regarding temperature and number density from these lines were estimated. The calculated number density from the Beer- Lambert Law was approximated to be about ~1011 molecules/cm3. The temperature was approximately to 240 to 260K with signal to noise ratio of about 100:1. The importance of this measurement technique was its capability to map individual absorption line for further studies.

  8. 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.

  9. Stratospheric ozone change and related climate impacts over 1850-2100 as modelled by the ACCMIP ensemble

    NASA Astrophysics Data System (ADS)

    Iglesias-Suarez, F.; Young, P. J.; Wild, O.

    2015-09-01

    Stratospheric ozone and associated climate impacts in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) simulations are evaluated in the recent past (1980-2000), and examined in the long-term (1850-2100) using the Representative Concentration Pathways low and high emission scenarios (RCP2.6 and RCP8.5, respectively) for the period 2000-2100. ACCMIP multi-model mean total column ozone (TCO) trends compare favourably, within uncertainty estimates, against observations. Particularly good agreement is seen in the Antarctic austral spring (-11.9 % dec-1 compared to observed ~ -13.8 ± 11 % dec-1), although larger deviations are found in the Arctic's boreal spring (-2.1 % dec-1 compared to observed ~ -5.3 ± 3 % dec-1). The simulated ozone hole has cooled the lower stratosphere during austral spring in the last few decades (-2.2 K dec-1). This cooling results in Southern Hemisphere summertime tropospheric circulation changes captured by an increase in the Southern Annular Mode (SAM) index (1.27 hPa dec-1). In the future, the interplay between the ozone hole recovery and greenhouse gases (GHGs) concentrations may result in the SAM index returning to pre-ozone hole levels or even with a more positive phase from around the second half of the century (-0.4 and 0.3 hPa dec-1 for the RCP2.6 and RCP8.5, respectively). By 2100, stratospheric ozone sensitivity to GHG concentrations is greatest in the Arctic and Northern Hemisphere midlatitudes (37.7 and 16.1 DU difference between the RCP2.6 and RCP8.5, respectively), and smallest over the tropics and Antarctica continent (2.5 and 8.1 DU respectively). Future TCO changes in the tropics are mainly determined by the upper stratospheric ozone sensitivity to GHG concentrations, due to a large compensation between tropospheric and lower stratospheric column ozone changes in the two RCP scenarios. These results demonstrate how changes in stratospheric ozone are tightly linked to climate and show the benefit of

  10. Stratospheric ozone change and related climate impacts over 1850-2100 as modelled by the ACCMIP ensemble

    NASA Astrophysics Data System (ADS)

    Iglesias-Suarez, F.; Young, P. J.; Wild, O.

    2016-01-01

    Stratospheric ozone and associated climate impacts in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) simulations are evaluated in the recent past (1980-2000), and examined in the long-term (1850-2100) using the Representative Concentration Pathways (RCPs) low- and high-emission scenarios (RCP2.6 and RCP8.5, respectively) for the period 2000-2100. ACCMIP multi-model mean total column ozone (TCO) trends compare favourably, within uncertainty estimates, against observations. Particularly good agreement is seen in the Antarctic austral spring (-11.9 % dec-1 compared to observed ˜ -13.9 ± 10.4 % dec-1), although larger deviations are found in the Arctic's boreal spring (-2.1 % dec-1 compared to observed ˜ -5.3 ± 3.3 % dec-1). The simulated ozone hole has cooled the lower stratosphere during austral spring in the last few decades (-2.2 K dec-1). This cooling results in Southern Hemisphere summertime tropospheric circulation changes captured by an increase in the Southern Annular Mode (SAM) index (1.3 hPa dec-1). In the future, the interplay between the ozone hole recovery and greenhouse gases (GHGs) concentrations may result in the SAM index returning to pre-ozone hole levels or even with a more positive phase from around the second half of the century (-0.4 and 0.3 hPa dec-1 for the RCP2.6 and RCP8.5, respectively). By 2100, stratospheric ozone sensitivity to GHG concentrations is greatest in the Arctic and Northern Hemisphere midlatitudes (37.7 and 16.1 DU difference between the RCP2.6 and RCP8.5, respectively), and smallest over the tropics and Antarctica continent (2.5 and 8.1 DU respectively). Future TCO changes in the tropics are mainly determined by the upper stratospheric ozone sensitivity to GHG concentrations, due to a large compensation between tropospheric and lower stratospheric column ozone changes in the two RCP scenarios. These results demonstrate how changes in stratospheric ozone are tightly linked to climate and show

  11. Validation of stratospheric ozone observed by the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment during 1992

    NASA Technical Reports Server (NTRS)

    Abrams, M. C.; Gunson, M. R.; Chang, A. Y.; Rinsland, C. P.; Zander, R.; Newchurch, M. H.

    1995-01-01

    Measurements of stratospheric ozone were made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment from onboard the Space Shuttle during the period 8-16 April 1992. The precision and accuracy of the measurements are discussed in the context of establishing the accuracy and compatibility of the measurements relative to other space-based measurements of ozone. Coincident measurements were obtained from the Stratospheric Aerosol and Gas Experiment (SAGE) 2 instrument onboard the Earth Radiation Budget Satellite (ERBS) and three instruments, the Microwave Limb Sounder (MLS), the Cryogenic Limb Array Etalon Spectrometer (CLAES), the Halogen Occultation Experiment (HALOE) onboard the Upper Atmospheric Research Satellite (UARS). Three of the instruments, ATMOS, SAGE-2 and MLS are demonstrated to be consistent to within +10% over the altitude range between 100 hPa and 0.5 hPa (approximately 20 to 60 km), with ATMOS and MLS displaying a zero mean bias and a root mean square deviation (rms) of 3% and SAGE-2 displaying an essentially systematic bias of -5% over the majority of the altitude range, except for below 30 hPa where SAGE-2 displays a large positive systematic bias due to the effect of the aerosol attenuation resulting from the Mt. Pinatubo volcanic eruption in 1991. The comparison with HALOE indicates that ozone levels observed by ATMOS are systematically higher than HALOE by 5 to 25% with a clear gradient in the differences; in contrast the comparison with CLAES displays differences of as much as + 30% with no obvious systematic scaling possible. Comparisons are evaluated in two separate schemes, by geographical coincidence and through zonal averages which illustrate the limitations of both schemes. Latitudinal and longitudinal variation are used to assess the sensitivity of the ATMOS measurements and to confirm the precision and accuracy, which should be less than 4% and 10% respectively.

  12. Trend analysis of the 20-year time series of stratospheric ozone profiles observed by the GROMOS microwave radiometer at Bern

    NASA Astrophysics Data System (ADS)

    Moreira, L.; Hocke, K.; Eckert, E.; von Clarmann, T.; Kämpfer, N.

    2015-10-01

    The ozone radiometer GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) has been performing continuous observations of stratospheric ozone profiles since 1994 above Bern, Switzerland (46.95° N, 7.44° E, 577 m). GROMOS is part of the Network for the Detection of Atmospheric Composition Change (NDACC). From November 1994 to October 2011, the ozone line spectra were measured by a filter bench (FB). In July 2009, a fast Fourier transform spectrometer (FFTS) was added as a back end to GROMOS. The new FFTS and the original FB measured in parallel for over 2 years. The ozone profiles retrieved separately from the ozone line spectra of FB and FFTS agree within 5 % at pressure levels from 30 to 0.5 hPa, from October 2009 to August 2011. A careful harmonisation of both time series has been carried out by taking the FFTS as the reference instrument for the FB. This enables us to assess the long-term trend derived from stratospheric ozone observations at Bern. The trend analysis was performed by using a robust multilinear parametric trend model which includes a linear term, the solar variability, the El Niño-Southern Oscillation (ENSO) index, the quasi-biennial oscillation (QBO), the annual and semi-annual oscillation and several harmonics with period lengths between 3 and 24 months. Over the last years, some experimental and modelling trend studies have shown that the stratospheric ozone trend is levelling off or even turning positive. With our observed ozone profiles, we are able to support this statement by reporting a statistically significant trend of +3.14 % decade-1 at 4.36 hPa (37.76 km), covering the period from January 1997 to January 2015, above Bern. Additionally, we have estimated a negative trend over this period of -3.94 % decade-1 at 0.2 hPa (59 km).

  13. Trend analysis of the 20 years time series of stratospheric ozone profiles observed by the GROMOS microwave radiometer at Bern

    NASA Astrophysics Data System (ADS)

    Moreira, L.; Hocke, K.; Eckert, E.; von Clarmann, T.; Kämpfer, N.

    2015-06-01

    The ozone radiometer GROMOS (GROund-based Millimeterwave Ozone Spectrometer) performs continuous observations of stratospheric ozone profiles since 1994 above Bern, Switzerland. GROMOS is part of the Network for the Detection of Atmospheric Composition Change (NDACC). From November 1994 to October 2011, the ozone line spectra were measured by a filter bench (FB). In July 2009, a Fast-Fourier-Transform spectrometer (FFTS) has been added as backend to GROMOS. The new FFTS and the original FB measured in parallel for over two years. The ozone profiles retrieved separately from the ozone line spectra of FB and FFTS agree within 5 % at pressure levels from 30 to 0.5 hPa, from October 2009 to August 2011. A careful harmonisation of both time series has been carried out by taking the FFTS as the reference instrument for the FB. This enables us to assess the long-term trend derived from more than 20 years of stratospheric ozone observations at Bern. The trend analysis has been performed by using a robust multilinear parametric trend model which includes a linear term, the solar variability, the El Niño-Southern Oscillation (ENSO) index, the quasi-biennial oscillation (QBO), the annual and semi-annual oscillation and several harmonics with period lengths between 3 and 24 months. Over the last years, some experimental and modelling trend studies have shown that the stratospheric ozone trend is levelling off or even turning positive. With our observed ozone profiles, we are able to support this statement by reporting a statistically significant trend of +3.14 % decade-1 at 4.36 hPa, covering the period from January 1997 to January 2015, above Bern. Additionally, we have estimated a negative trend over this period of -3.94 % decade-1 at 0.2 hPa.

  14. Distribution of the Effect of Solar Proton Flux And Geomagnetic Activity on the Stratospheric Ozone Profile

    NASA Astrophysics Data System (ADS)

    Velinov, P. I. Y.; Tassev, Y.; Yanev, T.; Tomova, D.

    Two-way MANOVA was used to examine the impact of two factors: 1) the proton flux intensity and 2) the geomagnetic activity on the dependant variable "ozone mixing ratio" which characterizes the stratospheric ozone profiles. The examination was carried out with fixed levels of two other factors: a) the heights at which the "ozone mixing ratio" was recorded, i,e, 35 km, 30.2 km, 24.5 km, 18.4 km, 15.6 km and b) the energetic intervals within which the proton flux was measured, i.e. =0,6-4,2 MeV; 4,2-8,7 MeV; 8,7-14,5 MeV; 15-44 MeV; 39-82 MeV; 84-200 MeV; 110-500 MeV. The analysis was performed for all combinations of levels of the factors a) and b) for which data was available. It was aimed at revealing which of the factors 1) and 2) were dominating with different combinations of the factors a) and b) with fixed levels. For this purpose a post hoc analysis was performed as well. The main results are as follows: factors 1) and 2) exert statistically significant impact on the dependant variable at all of the heights examined, but not for all of energetic intervals; increase of the ozone mixing ratio was observed as a main effect of the proton flux intensity at heights 24.5 km, 18.4 km, 15.6 km, but the analysis of the simultaneous acting of factors 1) and 2) revealed a decrease of the dependant variable at these heights; these effects possibly indicate the existence of two different mechanisms of impact on the ozone mixing ratio; the afore- discussed effects decrease with the height and therefore their graphical image was named "Christmas tree".

  15. Three dimensional model calculations of the global dispersion of high speed aircraft exhaust and implications for stratospheric ozone loss

    NASA Technical Reports Server (NTRS)

    Douglass, Anne R.; Rood, Richard B.; Jackman, Charles H.; Weaver, Clark J.

    1994-01-01

    Two-dimensional (zonally averaged) photochemical models are commonly used for calculations of ozone changes due to various perturbations. These include calculating the ozone change expected as a result of change in the lower stratospheric composition due to the exhaust of a fleet of supersonic aircraft flying in the lower stratosphere. However, zonal asymmetries are anticipated to be important to this sort of calculation. The aircraft are expected to be restricted from flying over land at supersonic speed due to sonic booms, thus the pollutant source will not be zonally symmetric. There is loss of pollutant through stratosphere/troposphere exchange, but these processes are spatially and temporally inhomogeneous. Asymmetry in the pollutant distribution contributes to the uncertainty in the ozone changes calculated with two dimensional models. Pollutant distributions for integrations of at least 1 year of continuous pollutant emissions along flight corridors are calculated using a three dimensional chemistry and transport model. These distributions indicate the importance of asymmetry in the pollutant distributions to evaluation of the impact of stratospheric aircraft on ozone. The implications of such pollutant asymmetries to assessment calculations are discussed, considering both homogeneous and heterogeneous reactions.

  16. Wavelet Analysis of Stratospheric SCIAMACHY Ozone - The Quest for the 27-day Cycle!

    NASA Astrophysics Data System (ADS)

    Dikty, S.; Weber, M.; Sonkaew, T.; Rozanov, A.; von Savigny, C.; Burrows, J. P.

    2009-04-01

    27-day cycle. Selected References: Gruzdev, A. N., Schmidt, H., Brasseur, G. P., 2008. The effect of the solar rotational irradiance variation on the middle and upper atmosphere calculated by a three-dimensional chemistry-climate model. Atmos. Chem. Phys. Dicuss., 8, 1113-1158. Hood, L. L., 1986. Coupled Stratospheric Ozone and Temperature Response to Short-Term Changes in Solar Ultraviolet Flux: An Analysis of Nimbus 7 SBUV and SAMS Data. J. Geophys. Res., 91, D4, 5264-5276. Hood, L. L., Zhou, S., 1998. Stratospheric effects of 27-day solar ultraviolet variations: An analysis of UARS MLS ozone and temperature data. J. Geophys. Res., 103, D3, 3629-3638. Ruzmaikin, A., Santee, M. L., Schwartz, M. J., Froidevaux, L., Pickett, H. M., 2007. The 27-day variations in stratospheric ozone and temperature: New MLS data. Geophys. Res. Lett., 34, doi:10.1029/2006GL02819. Skupin, J., Weber, M., Noel, S., Bovensmann, H., Burrows, J.P., 2005. GOME and SCIAMACHY solar measurements: Solar spectral irradiance and Mg II solar activity proxy indicator. Mem. S.A.It., 76, 1038-1041.

  17. Impact of a potential 21st century "grand solar minimum" on surface temperatures and stratospheric ozone

    NASA Astrophysics Data System (ADS)

    Anet, J. G.; Rozanov, E. V.; Muthers, S.; Peter, T.; BröNnimann, S.; Arfeuille, F.; Beer, J.; Shapiro, A. I.; Raible, C. C.; Steinhilber, F.; Schmutz, W. K.

    2013-08-01

    We investigate the effects of a recently proposed 21st century Dalton minimum like decline of solar activity on the evolution of Earth's climate and ozone layer. Three sets of two member ensemble simulations, radiatively forced by a midlevel emission scenario (Intergovernmental Panel on Climate Change RCP4.5), are performed with the atmosphere-ocean chemistry-climate model AOCCM SOCOL3-MPIOM, one with constant solar activity, the other two with reduced solar activity and different strength of the solar irradiance forcing. A future grand solar minimum will reduce the global mean surface warming of 2 K between 1986-2005 and 2081-2100 by 0.2 to 0.3 K. Furthermore, the decrease in solar UV radiation leads to a significant delay of stratospheric ozone recovery by 10 years and longer. Therefore, the effects of a solar activity minimum, should it occur, may interfere with international efforts for the protection of global climate and the ozone layer.

  18. Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model

    NASA Astrophysics Data System (ADS)

    Emili, Emanuele; Barret, Brice; Massart, Sebastien; Piacentini, Andrea; Pannekoucke, Olivier; Cariolle, Daniel

    2013-04-01

    Ozone acts as the main shield against UV radiation in the stratosphere, it contributes to the greenhouse effect in the troposphere and it is a major pollutant in the planetary boundary layer. In the last decades models and satellite observations reached a mature level, providing estimates of ozone with an accuracy of few percents in the stratosphere. On the other hand, tropospheric ozone still represents a challenge, because its signal is less detectable by space-borne sensors, its modelling depends on the knowledge of gaseous emissions at the surface, and stratosphere/troposphere exchanges might rapidly increase its abundance by several times. Moreover there is generally lack of in-situ observations of tropospheric ozone in many regions of the world. For these reasons the assimilation of satellite data into chemical transport models represents a promising technique to overcome limitations of both satellites and models. The objective of this study is to assess the value of vertically resolved observations from the Infrared Atmospheric Sounding Interferometer (IASI) and the Microwave Limb Sounder (MLS) to constrain both the tropospheric and stratospheric ozone profile in a global model. While ozone total columns and stratospheric profiles from UV and microwave sensors are nowadays routinely assimilated in operational models, still few studies have explored the assimilation of ozone products from IR sensors such as IASI, which provide better sensitivity in the troposphere. We assimilate both MLS ozone profiles and IASI tropospheric (1000-225 hPa) ozone columns in the Météo France chemical transport model MOCAGE for 2008. The model predicts ozone concentrations on a 2x2 degree global grid and for 60 vertical levels, ranging from the surface up to 0.1 hPa. The assimilation is based on a 4D-VAR algorithm, employs a linear chemistry scheme and accounts for the satellite vertical sensitivity via the averaging kernels. The assimilation of the two products is first tested

  19. Effects of Pinatubo aerosol on stratospheric ozone at mid-latitudes

    NASA Technical Reports Server (NTRS)

    Weaver, A.; Loewenstein, M.; Podolske, J. R.; Strahan, S. E.; Proffitt, M. H.; Aikin, K.; Margitan, J. J.; Jonsson, H. H.; Brock, C. A.; Wilson, J. C.

    1993-01-01

    Mid-latitude ozone data from ER-2 aircraft measurements in 1989, 1991, and 1992 were examined to determine how sulfate aerosols from the eruption of Mt. Pinatubo had affected ozone at about 18 km. N2O was used as a tracer to help distinguish between chemical and dynamical aerosol effects. At 20-45 deg N in February 1992, ozone was about 10-20% lower than February 1989 and 1991, with respect to N2O. Data from Aug. 1991 - Mar. 1992 showed changes in ozone with respect to N2O, but the magnitude of those changes was not correlated with the magnitude of the changes in aerosol surface area density.

  20. SAGE studies of the waves and eddy fluxes of ozone and temperature near 55 deg during the late February 1979 stratospheric warming

    NASA Technical Reports Server (NTRS)

    Wang, P.-H.

    1985-01-01

    Ozone data from the Stratospheric Aerosol and Gas Experiment have been used in conjunction with meteorological information to study the waves and eddy fluxes of ozone and temperature near 55 deg N during the late February 1979 stratospheric warming. The results indicate an intense poleward eddy ozone transport in the altitude range between approximately 24 and 38 km, and an equatorward transport above an altitude of about 38 km. It is found that this equatorward eddy ozone transport in the upper stratosphere was accompanied by a poleward eddy heat transport, as expected on the basis of the ozone photochemistry. The results also indicate that the phase relationship between ozone and temperature waves agrees qualitatively with existing model analyses.

  1. 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

  2. From stratospheric ozone to climate change: historical perspective on precaution and scientific responsibility.

    PubMed

    Mégie, Gérard

    2006-10-01

    The issue of the impact of human activities on the stratospheric ozone layer emerged in the early 1970s. But international regulations to mitigate the most serious effects were not adopted until the mid-1980s. This case holds lessons for addressing more complex environmental problems. Concepts that should inform discussion include 'latency,' 'counter-factual scenario based on the Precautionary Principle,' 'inter-generational burden sharing,' and 'estimating global costs under factual and counter-factual regulatory scenarios.' Stringent regulations were adopted when large scientific uncertainty existed, and the environmental problem would have been prevented or more rapidly mitigated, at relatively modest incremental price, but for a time delay before more rigorous Precautionary measures were implemented. Will history repeat itself in the case of climate change?

  3. Laboratory Studies of Chemical and Photochemical Processes Relevant to Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Villalta, P. W.; Zahniser, M. S.; Nelson, D. D.; Kolb, C. E.

    1998-01-01

    This is the final report for this project. Its purpose is to reduce the uncertainty in rate coefficients for key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring the rate coefficients for the reactions of HO2 + O3, and HO2 + NO2 in the temperature range (200-240 K) relevant to the lower stratosphere. In order to accomplish this, a high pressure turbulent flow tube reactor was built and its flow characteristics were quantified. The instrument was coupled with tunable diode laser spectroscopy for HO2 detection. Room temperature measurements of the HO2 + NO2 rate coefficients over the pressure range of 50-300 torr agree well with previous measurements. Preliminary measurements of the HO2 + O, rate coefficients at 50 - 300 Torr over the temperature range of 208-294 K agree with the NASA evaluation from 294-225 K but deviate significantly (50 % higher) at approximately 210 K.

  4. Fine-scale study of a thick stratospheric ozone lamina at the edge of the southern subtropical barrier

    NASA Astrophysics Data System (ADS)

    Portafaix, Thierry; Morel, BéAtrice; Bencherif, Hassan; Baldy, Serge; Godin-Beekmann, Sophie; Hauchecorne, Alain

    2003-03-01

    A large-scale transport event resulting in a thick ozone lamina originating from midlatitudes is observed in the tropical stratosphere over Reunion island (55°E, 21°S). This isentropic transport was detected from stratospheric balloon-borne ozone measurements that showed the occurrence of the lamina and was investigated using different tools based on Ertel's potential vorticity (Epv) analyses. An original software (DYBAL) using surface coordinate and the equivalent length of Epv contours as diagnostic tools in conjunction with high-resolution outputs from an Epv advection model MIMOSA allows us to specify the origin of the lamina. The results indicate that a broad layer of stratospheric air was isentropically advected from midlatitudes across the southern edge of tropical reservoir and reached Reunion island on 12 July 2000. In addition, Eliassen-Palm's flux vectors, calculated from ECMWF analysis, show that planetary wave activity was quite large during that time period, with wave-breaking occurring around 30 km, and could have driven that exchange. In contrast with analyses of filamentation events based on model and satellite data, the present study focuses on a fine-scale vertical survey from in situ measurements. The filament reported in this paper is characterized by a large vertical extension and is located around the maximum of ozone concentration in the tropical stratosphere (600 K). The analysis of such events, poorly documented in the tropics, could complement satellite studies and contribute to a better determination of the transport between the tropics and the midlatitudes.

  5. The stratospheric ozone response to a discrepancy of the SSI data

    NASA Astrophysics Data System (ADS)

    Rozanov, E.; Shapiro, A. V.; Harder, J. W.; Egorova, T. A.; Schmutz, W. K.; Peter, T.

    2011-12-01

    The solar radiation, which is the main energy source in the Earth atmosphere, is highly variable especially at the ultraviolet region of the solar spectrum. The UV radiation penetrates down to the stratosphere and its variability can lead to the substantial response of the atmosphere. In particular, the variability of the irradiance in Herzberg continuum (200-242 nm) and Hartley band (200-300 nm) strongly influences the ozone concentration. The recent SIM and SOLSTICE measurements onboard SORCE satellite show absolutely unexpected behavior of solar irradiance variability. The 11-year activity trends of the solar irradiance have different signs in the visible and UV regions. Besides the variability in UV is several times higher than all recent estimates (e.g., Lean et. al., 2005). Moreover the irradiance variability measured by SIM is different from measured by SOLSTICE in their common spectral part. To investigate an influence of these discrepancies to the ozone response we run 3D climate-chemistry model SOCOL forced by the different SSI datasets. The SSI input for the SOCOL model is the spectral solar irradiance from 121 to 750 nm. We used three different datasets reconstructed by Lean 2005 and two composites of measurements. First one is based on SOLSTICE measurements up to 210 nm and SIM outwards (SIM dominated dataset) and the second one is based on SOLSTICE measurements up to 290 nm and SIM outwards (SOLSTICE dominated dataset). We have simulated atmospheric response for period from May 2004 to February 2009. We have analyzed the ozone response using multiple regression analysis and found that the response strongly depends on the applied SSI dataset. The data should be analyzed with a special care as both solar irradiance and chlorine family concentration have downtrend during the period of simulation. Both these factors strongly influence the ozone concentration so they have to be separated. To investigate ozone response to the chlorine changes we have made

  6. Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model

    NASA Astrophysics Data System (ADS)

    Emili, E.; Barret, B.; Massart, S.; Le Flochmoen, E.; Piacentini, A.; El Amraoui, L.; Pannekoucke, O.; Cariolle, D.

    2013-08-01

    Accurate and temporally resolved fields of free-troposphere ozone are of major importance to quantify the intercontinental transport of pollution and the ozone radiative forcing. In this study we examine the impact of assimilating ozone observations from the Microwave Limb Sounder (MLS) and the Infrared Atmospheric Sounding Interferometer (IASI) in a global chemical transport model (MOdèle de Chimie Atmosphérique à Grande Échelle, MOCAGE). The assimilation of the two instruments is performed by means of a variational algorithm (4-D-VAR) and allows to constrain stratospheric and tropospheric ozone simultaneously. The analysis is first computed for the months of August and November 2008 and validated against ozone-sondes measurements to verify the presence of observations and model biases. It is found that the IASI Tropospheric Ozone Column (TOC, 1000-225 hPa) should be bias-corrected prior to assimilation and MLS lowermost level (215 hPa) excluded from the analysis. Furthermore, a longer analysis of 6 months (July-August 2008) showed that the combined assimilation of MLS and IASI is able to globally reduce the uncertainty (Root Mean Square Error, RMSE) of the modeled ozone columns from 30% to 15% in the Upper-Troposphere/Lower-Stratosphere (UTLS, 70-225 hPa) and from 25% to 20% in the free troposphere. The positive effect of assimilating IASI tropospheric observations is very significant at low latitudes (30° S-30° N), whereas it is not demonstrated at higher latitudes. Results are confirmed by a comparison with additional ozone datasets like the Measurements of OZone and wAter vapour by aIrbus in-service airCraft (MOZAIC) data, the Ozone Monitoring Instrument (OMI) total ozone columns and several high-altitude surface measurements. Finally, the analysis is found to be little sensitive to the assimilation parameters and the model chemical scheme, due to the high frequency of satellite observations compared to the average life-time of free-troposphere/low-stratosphere

  7. A post-Kyoto partner: considering the stratospheric ozone regime as a tool to manage nitrous oxide.

    PubMed

    Kanter, David; Mauzerall, Denise L; Ravishankara, A R; Daniel, John S; Portmann, Robert W; Grabiel, Peter M; Moomaw, William R; Galloway, James N

    2013-03-19

    Nitrous oxide (N2O) is the largest known remaining anthropogenic threat to the stratospheric ozone layer. However, it is currently only regulated under the 1997 Kyoto Protocol because of its simultaneous ability to warm the climate. The threat N2O poses to the stratospheric ozone layer, coupled with the uncertain future of the international climate regime, motivates our exploration of issues that could be relevant to the Parties to the ozone regime (the 1985 Vienna Convention and its 1987 Montreal Protocol) should they decide to take measures to manage N2O in the future. There are clear legal avenues to regulate N2O under the ozone regime as well as several ways to share authority with the existing and future international climate treaties. N2O mitigation strategies exist to address the most significant anthropogenic sources, including agriculture, where behavioral practices and new technologies could contribute significantly to reducing emissions. Existing policies managing N2O and other forms of reactive nitrogen could be harnessed and built on by the ozone regime to implement N2O controls. There are several challenges and potential cobenefits to N2O control which we discuss here: food security, equity, and implications of the nitrogen cascade. The possible inclusion of N2O in the ozone regime need not be viewed as a sign of failure of the United Nations Framework Convention on Climate Change to adequately deal with climate change. Rather, it could represent an additional valuable tool in sustainable development diplomacy. PMID:23440192

  8. A post-Kyoto partner: considering the stratospheric ozone regime as a tool to manage nitrous oxide.

    PubMed

    Kanter, David; Mauzerall, Denise L; Ravishankara, A R; Daniel, John S; Portmann, Robert W; Grabiel, Peter M; Moomaw, William R; Galloway, James N

    2013-03-19

    Nitrous oxide (N2O) is the largest known remaining anthropogenic threat to the stratospheric ozone layer. However, it is currently only regulated under the 1997 Kyoto Protocol because of its simultaneous ability to warm the climate. The threat N2O poses to the stratospheric ozone layer, coupled with the uncertain future of the international climate regime, motivates our exploration of issues that could be relevant to the Parties to the ozone regime (the 1985 Vienna Convention and its 1987 Montreal Protocol) should they decide to take measures to manage N2O in the future. There are clear legal avenues to regulate N2O under the ozone regime as well as several ways to share authority with the existing and future international climate treaties. N2O mitigation strategies exist to address the most significant anthropogenic sources, including agriculture, where behavioral practices and new technologies could contribute significantly to reducing emissions. Existing policies managing N2O and other forms of reactive nitrogen could be harnessed and built on by the ozone regime to implement N2O controls. There are several challenges and potential cobenefits to N2O control which we discuss here: food security, equity, and implications of the nitrogen cascade. The possible inclusion of N2O in the ozone regime need not be viewed as a sign of failure of the United Nations Framework Convention on Climate Change to adequately deal with climate change. Rather, it could represent an additional valuable tool in sustainable development diplomacy.

  9. A post-Kyoto partner: Considering the stratospheric ozone regime as a tool to manage nitrous oxide

    PubMed Central

    Kanter, David; Mauzerall, Denise L.; Ravishankara, A. R.; Daniel, John S.; Portmann, Robert W.; Grabiel, Peter M.; Moomaw, William R.; Galloway, James N.

    2013-01-01

    Nitrous oxide (N2O) is the largest known remaining anthropogenic threat to the stratospheric ozone layer. However, it is currently only regulated under the 1997 Kyoto Protocol because of its simultaneous ability to warm the climate. The threat N2O poses to the stratospheric ozone layer, coupled with the uncertain future of the international climate regime, motivates our exploration of issues that could be relevant to the Parties to the ozone regime (the 1985 Vienna Convention and its 1987 Montreal Protocol) should they decide to take measures to manage N2O in the future. There are clear legal avenues to regulate N2O under the ozone regime as well as several ways to share authority with the existing and future international climate treaties. N2O mitigation strategies exist to address the most significant anthropogenic sources, including agriculture, where behavioral practices and new technologies could contribute significantly to reducing emissions. Existing policies managing N2O and other forms of reactive nitrogen could be harnessed and built on by the ozone regime to implement N2O controls. There are several challenges and potential cobenefits to N2O control which we discuss here: food security, equity, and implications of the nitrogen cascade. The possible inclusion of N2O in the ozone regime need not be viewed as a sign of failure of the United Nations Framework Convention on Climate Change to adequately deal with climate change. Rather, it could represent an additional valuable tool in sustainable development diplomacy. PMID:23440192

  10. Investigation of Ozone Sources in California Using AJAX Airborne Measurements and Models: Implications for Stratospheric Intrusion and Long Range Transport

    NASA Technical Reports Server (NTRS)

    Ryoo, Ju-Mee; Johnson, Matthew S.; Iraci, Laura T.; Yates, Emma L.; Pierce, R. Bradley; Tanaka, Tomoaki; Gore, Warren

    2015-01-01

    High ozone concentrations at low altitudes near the surface were detected from airborne Alpha Jet Atmospheric eXperiment (AJAX) measurements on May 30, 2012. We investigate the causes of the elevated ozone concentrations using the airborne measurements and various models. GEOS-chem and WRF-STILT model simulations show that the contribution from local sources is small. From MERRA reanalysis, it is found that high potential vorticity (PV) is observed at low altitudes. This high PV appears to be only partially coming through the stratospheric intrusions because the air inside the high PV region is moist, which shows that mixing appears to be enhanced in the low altitudes. Considering that diabatic heating can also produce high PV in the lower troposphere, high ozone is partially coming through stratospheric intrusion, but this cannot explain the whole ozone concentration in the target areas of the western U.S. A back-trajectory model is utilized to see where the air masses originated. The air masses of the target areas came from the lower stratosphere (LS), upper (UT), mid- (MT), and lower troposphere (LT). The relative number of trajectories coming from LS and UT is low (7.7 and 7.6, respectively) compared to that from LT (64.1), but the relative ozone concentration coming from LS and UT is high (38.4 and 20.95, respectively) compared to that from LT (17.7). The air mass coming from LT appears to be mostly coming from Asia. Q diagnostics show that there is sufficient mixing along the trajectory to indicate that ozone from the different origins is mixed and transported to the western U.S. This study shows that high ozone concentrations can be detected by airborne measurements, which can be analyzed by integrated platforms such as models, reanalysis, and satellite data.

  11. Investigating Ozone Sources in California Using AJAX Airborne Measurements and Models: Implications for Stratospheric Intrusion and Long Range Transport

    NASA Technical Reports Server (NTRS)

    Ryoo, Ju-Mee; Johnson, Matthew S.; Iraci, Laura T.; Yates, Emma L.; Pierce, R. Bradley; Tanaka, Tomoaki; Gore, Warren

    2016-01-01

    High ozone concentrations at low altitudes near the surface were detected from airborne Alpha Jet Atmospheric eXperiment (AJAX) measurements on May 30, 2012. We investigate the causes of the elevated ozone concentrations using the airborne measurements and various models. GEOSchem and WRF-STILT model simulations show that the contribution from local sources is small. From MERRA reanalysis, it is found that high potential vorticity (PV) is observed at low altitudes. This high PV appears to be only partially coming through the stratospheric intrusions because the air inside the high PV region is moist, which shows that mixing appears to be enhanced in the low altitudes. Considering that diabatic heating can also produce high PV in the lower troposphere, high ozone is partially coming through stratospheric intrusion, but this cannot explain the whole ozone concentration in the target areas of the western U.S. A back-trajectory model is utilized to see where the air masses originated. The air masses of the target areas came from the lower stratosphere (LS), upper (UT), mid- (MT), and lower troposphere (LT). The relative number of trajectories coming from LS and UT is low (7.7% and 7.6%, respectively) compared to that from LT (64.1%), but the relative ozone concentration coming from LS and UT is high (38.4% and 20.95%, respectively) compared to that from LT (17.7%). The air mass coming from LT appears to be mostly coming from Asia. Q diagnostics show that there is sufficient mixing along the trajectory to indicate that ozone from the different origins is mixed and transported to the western U.S. This study shows that high ozone concentrations can be detected by airborne measurements, which can be analyzed by integrated platforms such as models, reanalysis, and satellite data.

  12. High-Latitude Stratospheric Sensitivity to QBO Width in a Chemistry-Climate Model with Parameterized Ozone Chemistry

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Braesicke, P.; Pyle, J. A.

    2010-01-01

    In a pair of idealized simulations with a simplified chemistry-climate model, the sensitivity of the wintertime Arctic stratosphere to variability in the width of the quasi-biennial oscillation (QBO) is assessed. The width of the QBO appears to have equal influence on the Arctic stratosphere as does the phase (i.e. the Holton-Tan mechanism). In the model, a wider QBO acts like a preferential shift toward the easterly phase of the QBO, where zonal winds at 60 N tend to be relatively weaker, while 50 hPa geopotential heights and polar ozone values tend to be higher.

  13. Diurnal ozone variations in the stratosphere revealed in observations from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on board the International Space Station (ISS)

    NASA Astrophysics Data System (ADS)

    Sakazaki, Takatoshi; Fujiwara, Masatomo; Mitsuda, Chihiro; Imai, Koji; Manago, Naohiro; Naito, Yoko; Nakamura, Tetsu; Akiyoshi, Hideharu; Kinnison, Douglas; Sano, Takuki; Suzuki, Makoto; Shiotani, Masato

    2013-04-01

    Considerable uncertainties remain in the global pattern of diurnal variation in stratospheric ozone, particularly lower to middle stratospheric ozone, which is the principal contributor to total column ozone. The Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) attached to the Japanese Experiment Module (JEM) on board the International Space Station (ISS) was developed to gather high-quality global measurements of stratospheric ozone at various local times, with the aid of superconducting mixers cooled to 4K by a compact mechanical cooler. Using the SMILES dataset, as well as data from nudged chemistry-climate models (MIROC3.2-CTM and SD-WACCM), we show that the SMILES observational data have revealed the global pattern of diurnal ozone variations throughout the stratosphere. We also found that these variations can be explained by both photochemistry and dynamics. The peak-to-peak difference in the stratospheric ozone mixing ratio (total column ozone) reached 8% (1%) over the course of a day. This variation needs to be considered when merging ozone data from different satellite measurements and even from measurements made using one specific instrument at different local times.

  14. Diurnal ozone variations in the stratosphere revealed in observations from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) onboard the International Space Station (ISS)

    NASA Astrophysics Data System (ADS)

    Sakazaki, Takatoshi; Fujiwara, Masatomo; Mitsuda, Chihiro; Imai, Koji; Manago, Naohiro; Naito, Yoko; Nakamura, Tetsu; Akiyoshi, Hideharu; Kinnison, Douglas; Sano, Takuki; Suzuki, Makoto; Shiotani, Masato

    2013-04-01

    Considerable uncertainties remain in the global pattern of diurnal variation in stratospheric ozone, particularly lower to middle stratospheric ozone, which is the principal contributor to total column ozone. The Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) attached to the Japanese Experiment Module (JEM) on board the International Space Station (ISS), was developed to gather high-quality global measurements of stratospheric ozone at various local times, with the aid of superconducting mixers cooled to 4 K by a compact mechanical cooler. Using the SMILES dataset, as well as data from nudged chemistry-climate models (MIROC3.2-CTM and SD-WACCM), we show that the SMILES observational data have revealed the global pattern of diurnal ozone variations throughout the stratosphere. We also found that these variations can be explained by both photochemistry and dynamics. The peak-to-peak difference in the stratospheric ozone mixing ratio (total column ozone) reached 8% (1%) over the course of a day. This variation needs to be considered when merging ozone data from different satellite measurements and even from measurements made using one specific instrument at different local times.

  15. The Stratospheric Aerosol and Gas Experiment III - International Space Station: Extending Long-Term Ozone and Aerosol Observations (Invited)

    NASA Astrophysics Data System (ADS)

    Eckman, R.; Zawodny, J. M.; Cisewski, M.; Gasbarre, J.; Flittner, D. E.; Hill, C.; Roell, M.; Moore, J. R.; Hernandez, G.; McCormick, M. P.

    2013-12-01

    The Stratospheric Aerosol and Gas Experiment III - International Space Station (SAGE III on ISS) will extend the global measurements of vertical profiles of ozone, aerosols, water vapor, nitrogen dioxide, and other trace gases begun with SAGE I in 1979, enabling the detection of long-term trends. SAGE III on ISS is the fourth in a series of instruments developed for monitoring these constituents in the stratosphere and troposphere. The SAGE III instrument is a moderate resolution spectrometer covering wavelengths from 290 nm to 1550 nm, using the heritage occultation technique, utilizing both the sun and the moon. Launch to ISS is planned for early 2015 aboard a Falcon 9 spacecraft. SAGE III will investigate the spatial and temporal variability of the measured species in order to determine their role in climatological processes, biogeochemical cycles, the hydrologic cycle, and atmospheric chemistry. It will characterize tropospheric, as well as stratospheric aerosols and upper tropospheric and stratospheric clouds, and investigate their effects on the Earth's environment including radiative, microphysical, and chemical interactions. The multi-decadal SAGE ozone and aerosol data sets have undergone intense scrutiny and are the international standard for accuracy and stability. SAGE data have been used to monitor the effectiveness of the Montreal Protocol. Amongst its key objectives will be to assess the state of the recovery in the distribution of ozone, to reestablish the aerosol measurements needed by both climate and ozone models, and to gain further insight into key processes contributing to ozone and aerosol variability. The ISS is ideal for Earth observing experiments; its mid-inclination orbit allows for a large range in latitude sampling and nearly continuous communications with payloads. In this presentation, we describe the SAGE III on ISS mission, its implementation, current status, and concentrate on its key science objectives.

  16. [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.

  17. Pollution prevention and stratospheric ozone layer protection through innovative procurement methods: The chiller basic ordering agreement

    SciTech Connect

    Snyder, R.E.; Coyle, J.E.; Guice, J.R. Jr.; Kale, S.H.

    1997-12-31

    The Department of Energy (DOE) and the General Services Administration (GSA) have devised an affirmative procurement vehicle to encourage replacement of chillers using chlorofluorocarbon (CFC) refrigerants harmful to the Earth`s stratospheric ozone layer. Procurement selections are based on lowest life cycle cost. Linked with a DOE-developed Equipment Specification for 100 to 2,000 ton chillers that is crafted broadly enough to address about 90% of the Federal water-cooled chiller procurements, the Basic Ordering Agreement (BOA) process significantly reduces redundant design, procurement, and other costs associated with Federal purchasing of chillers through the cutting of red tape associated with buying industrial equipment. While serving to minimize the release of ozone-depleting substances (about six million tons of CFCs) to the environment, the installation of more energy-efficient chillers also promotes environmental stewardship in that reduced energy consumption translates into reduced emissions of noxious gases from the generation of electricity. Use of the BOA to purchase chillers consistent with Federal energy efficiency standards will contribute to reductions of almost a million tons annually of nitrous oxides, sulfur dioxide, and other pollutants from power plant emissions. Reduced electricity consumption of approximately 1.5 billion kilowatt hours per year by switching to more efficient chillers equates to an annual monetary savings of $75 million.

  18. Processes Affecting Tropospheric Ozone over Africa

    NASA Technical Reports Server (NTRS)

    Diab, Roseanne D.; Thompson, Anne M.

    2004-01-01

    This is a Workshop Report prepared for Eos, the weekly AGU magazine, The workshop took place between 26-28 January 2004 at the University of KwaZulu-Natal in Durban, South Africa and was attended by 26 participants (http//www.geography.und.ac.za). Considerable progress has been made in ozone observations except for northern Africa (large data gaps) and west Africa (to be covered by the French-sponsored AMMA program). The present-day ozone findings were evaluated and reviewed by speakers using Aircraft data (MOZAIC program), NASA satellites (MOPITT, TRMM, TOMS) and ozone soundings (SHADOZ). Besides some ozone gaps, there are challenges posed by the need to assess the relative strengths of photochemical and dynamic influences on the tropospheric ozone budget. Biogenic, biofuels, biomass burning sources of ozone precursors remain highly uncertain. Recent findings (by NASA's Chatfield and Thompson, using satellite and sounding data) show significant impact of Indian Ocean pollution on African ozone. European research on pollutants over the Mediterranean and the middle east, that suggests that ozone may be exported to Africa from these areas, also needs to be considered.

  19. Atmospheric Hydroperoxides in West Antarctica: Links to Stratospheric Ozone and Atmospheric Oxidation Capacity

    NASA Technical Reports Server (NTRS)

    Frey, Markus M.; Stewart, Richard W.; McConnell, Joseph R.; Bales, Roger C.

    2005-01-01

    The troposphere above the West Antarctic Ice Sheet (WAIS) was sampled for hydroperoxides at 21 locations during 2-month-long summer traverses from 2000 to 2002, as part of US ITASE (International Transantarctic Scientific Expedition). First time quantitative measurements using an HPLC method showed that methylhydroperoxide (MHP) is the only important organic hydroperoxide occurring in the Antarctic troposphere, and that it is found at levels ten times those previously predicted by photochemical models. During three field seasons, means and standard deviations for hydrogen peroxide (H2O2) were 321+/-158 pptv, 650+/-176 pptv and 330+/-147 pptv. While MHP was detected, but not quantified in December 2000, levels in summer 2001 and 2002 were 317+128 pptv and 304+/-172.2 pptv. Results from firn air experiments and diurnal variability of the two species showed that atmospheric H2O2 is significantly impacted by a physical snow pack source between 76 and 90degS, whereas MHP is not. We show strong evidence of a positive feedback between stratospheric ozone and H2O2 at the surface. Between November-27 and December-12 in 2001, when ozone column densities dropped below 220 DU (means in 2000 and 2001 were 318 DU and 334 DU, respectively), H2O2 was 1.7 times that observed in the same period in 2000 and 2002, while MHP was only 80% of the levels encountered in 2002. Photochemical box model runs suggest that NO and OH levels on WAIS are closer to coastal values, while Antarctic Plateau levels are higher, confirming that region to be a highly oxidizing environment. The modeled sensitivity of H2O2 and particularly MHP to NO offers the potential to use atmospheric hydroperoxides to constrain the NO background and thus estimate the past oxidation capacity of the remote atmosphere. Index Terms: 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry; 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 1610 Global Change: Atmosphere (03

  20. New differential absorption lidar for stratospheric ozone monitoring in Patagonia, South Argentina

    NASA Astrophysics Data System (ADS)

    Wolfram, E. A.; Salvador, J.; D'Elia, R.; Casiccia, C.; Paes Leme, N.; Pazmiño, A.; Porteneuve, J.; Godin-Beekman, S.; Nakane, H.; Quel, E. J.

    2008-10-01

    As part of environmental studies concerned with measurements of the stratospheric ozone layer, CEILAP has developed a new differential absorption lidar (DIAL) instrument. Since the initial construction of the first DIAL instrument, the Lidar Division of CEILAP has made important financial and scientific investments to upgrade this initial prototype. The new version has a bigger reception system formed by four Newtonian telescopes, each of 50 cm diameter, and a larger number of detection channels: four different wavelengths are detected simultaneously and six digital channels record the Rayleigh and Raman backscattered photons emitted by a ClXe excimer laser at 308 nm and the third harmonic of a Nd-YAG laser at 355 nm. A number of different changes have been made to increase the dynamic range of this lidar: a mechanical chopper was installed together with a gated photomultiplier in the high-energy detection channels to avoid the detector being overloaded by strong signals from lower atmospheric layers. This new version was installed inside a shelter, giving the possibility to make field campaigns outside CEILAP laboratories, for example the SOLAR campaign made in the Argentine Patagonian region during 2005 and 2006 spring periods. In this paper a full description of the instrument update is given. Intercomparisons with the ozone sonde and satellite platform instrument are presented. The results show agreement better than 10% in 16-38 km altitude range when the same airmasses are sampled. The comparison with five quasi-coincident sondes launched in Punta Arenas during spring 2005 shows good agreement between both types of measurement, with relative differences inside 1σ deviation of the lidar measurement. The comparison of the integral of height integrated lidar profiles with total ozone column measured with a Brewer photometer shows good agreement, with relative differences less than 10%.