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Sample records for extreme stratospheric aerosol

  1. Stratospheric aerosols

    International Nuclear Information System (INIS)

    Rosen, J.; Ivanov, V.A.

    1993-01-01

    Stratospheric aerosol measurements can provide both spatial and temporal data of sufficient resolution to be of use in climate models. Relatively recent results from a wide range of instrument techniques for measuring stratospheric aerosol parameters are described. Such techniques include impactor sampling, lidar system sensing, filter sampling, photoelectric particle counting, satellite extinction-sensing using the sun as a source, and optical depth probing, at sites mainly removed from tropospheric aerosol sources. Some of these techniques have also had correlative and intercomparison studies. The main methods for determining the vertical profiles of stratospheric aerosols are outlined: lidar extinction measurements from satellites; impactor measurements from balloons and aircraft; and photoelectric particle counter measurements from balloons, aircraft, and rockets. The conversion of the lidar backscatter to stratospheric aerosol mass loading is referred to. Absolute measurements of total solar extinction from satellite orbits can be used to extract the aerosol extinction, and several examples of vertical profiles of extinction obtained with the SAGE satellite are given. Stratospheric mass loading can be inferred from extinction using approximate linear relationships but under restrictive conditions. Impactor sampling is essentially the only method in which the physical nature of the stratospheric aerosol is observed visually. Vertical profiles of stratospheric aerosol number concentration using impactor data are presented. Typical profiles using a dual-size-range photoelectric dustsonde particle counter are given for volcanically disturbed and inactive periods. Some measurements of the global distribution of stratospheric aerosols are also presented. Volatility measurements are described, indicating that stratospheric aerosols are composed primarily of about 75% sulfuric acid and 25% water

  2. Reduction of photosynthetically active radiation under extreme stratospheric aerosol loads

    International Nuclear Information System (INIS)

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

    1981-08-01

    The recently published hypothesis that the Cretaceous-Tertiary extinctions might be caused by an obstruction of sunlight is tested by model calculations. First we compute the total mass of stratospheric aerosols under normal atmospheric conditions for four different (measured) aerosol size distributions and vertical profiles. For comparison, the stratospheric dust masses after four volcanic eruptions are also evaluated. Detailed solar radiative transfer calculations are then performed for artificially increased aerosol amounts until the postulated darkness scenario is obtained. Thus we find that a total stratospheric aerosol mass between 1 and 4 times 10 1 g is sufficient to reduce photosynthesis to 10 -3 of normal. We also infer from this result tha the impact of a 0.4- to 3-km-diameter asteroid or a close encounter with a Halley-size comet may deposit that amount of particulates into the stratosphere. The darkness scenario of Alvarez et al. is thus shown to be a possible extinction mechanism, even with smaller size asteroids of comets than previously estimated

  3. Possible effect of extreme solar energetic particle event of 20 January 2005 on polar stratospheric aerosols: direct observational evidence

    Directory of Open Access Journals (Sweden)

    I. A. Mironova

    2012-01-01

    Full Text Available Energetic cosmic rays are the main source of ionization of the low-middle atmosphere, leading to associated changes in atmospheric properties. Via the hypothetical influence of ionization on aerosol growth and facilitated formation of clouds, this may be an important indirect link relating solar variability to climate. This effect is highly debated, however, since the proposed theoretical mechanisms still remain illusive and qualitative, and observational evidence is inconclusive and controversial. Therefore, important questions regarding the existence and magnitude of the effect, and particularly the fraction of aerosol particles that can form and grow, are still open. Here we present empirical evidence of the possible effect caused by cosmic rays upon polar stratospheric aerosols, based on a case study of an extreme solar energetic particle (SEP event of 20 January 2005. Using aerosol data obtained over polar regions from different satellites with optical instruments that were operating during January 2005, such as the Stratospheric Aerosol and Gas Experiment III (SAGE III, and Optical Spectrograph and Infrared Imaging System (OSIRIS, we found a significant simultaneous change in aerosol properties in both the Southern and Northern Polar regions in temporal association with the SEP event. We speculate that ionization of the atmosphere, which was abnormally high in the lower stratosphere during the extreme SEP event, might have led to formation of new particles and/or growth of preexisting ultrafine particles in the polar stratospheric region. However, a detailed interpretation of the effect is left for subsequent studies. This is the first time high vertical resolution measurements have been used to discuss possible production of stratospheric aerosols under the influence of cosmic ray induced ionization. The observed effect is marginally detectable for the analyzed severe SEP event and can be undetectable for the majority of weak

  4. Possible effect of extreme solar energetic particle event of 20 January 2005 on polar stratospheric aerosols: direct observational evidence

    Science.gov (United States)

    Mironova, I. A.; Usoskin, I. G.; Kovaltsov, G. A.; Petelina, S. V.

    2012-01-01

    Energetic cosmic rays are the main source of ionization of the low-middle atmosphere, leading to associated changes in atmospheric properties. Via the hypothetical influence of ionization on aerosol growth and facilitated formation of clouds, this may be an important indirect link relating solar variability to climate. This effect is highly debated, however, since the proposed theoretical mechanisms still remain illusive and qualitative, and observational evidence is inconclusive and controversial. Therefore, important questions regarding the existence and magnitude of the effect, and particularly the fraction of aerosol particles that can form and grow, are still open. Here we present empirical evidence of the possible effect caused by cosmic rays upon polar stratospheric aerosols, based on a case study of an extreme solar energetic particle (SEP) event of 20 January 2005. Using aerosol data obtained over polar regions from different satellites with optical instruments that were operating during January 2005, such as the Stratospheric Aerosol and Gas Experiment III (SAGE III), and Optical Spectrograph and Infrared Imaging System (OSIRIS), we found a significant simultaneous change in aerosol properties in both the Southern and Northern Polar regions in temporal association with the SEP event. We speculate that ionization of the atmosphere, which was abnormally high in the lower stratosphere during the extreme SEP event, might have led to formation of new particles and/or growth of preexisting ultrafine particles in the polar stratospheric region. However, a detailed interpretation of the effect is left for subsequent studies. This is the first time high vertical resolution measurements have been used to discuss possible production of stratospheric aerosols under the influence of cosmic ray induced ionization. The observed effect is marginally detectable for the analyzed severe SEP event and can be undetectable for the majority of weak-moderate events. The present

  5. Reduction of photosynthetically active radiation under extreme stratospheric-aerosol loads

    International Nuclear Information System (INIS)

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

    1981-01-01

    The recently published hypothesis that the Cretaceous-Tertiary extinctions might be caused by an obstruction of sunlight is tested by model calculations. First we compute the total mass of stratospheric aerosols under normal atmospheric conditions for four different (measured) aerosol size distributions and vertical profiles. For comparison, the stratospheric dust masses after four volcanic eruptions are also evaluated. Detailed solar radiative transfer calculations are then performed for artificially increased aerosol amounts until the postulated darkness scenario is obtained. Thus we find that a total stratospheric aerosol mass between 1 and 4 times 10 16 g is sufficient to reduce photosynthesis to 10 3 of normal. We also infer from this result that the impact of a 0.4- to 3-km-diameter asteroid or a close encounter with a Halley-size comet may deposit that amount of particulates into the stratosphere. The darkness scenario of Alvarez et al., is thus shown to be a possible extinction mechanism, even with smaller size asteroids or comets than previously estimated

  6. Stratospheric aerosol geoengineering

    Energy Technology Data Exchange (ETDEWEB)

    Robock, Alan [Department of Environmental Sciences, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901 (United States)

    2015-03-30

    The Geoengineering Model Intercomparison Project, conducting climate model experiments with standard stratospheric aerosol injection scenarios, has found that insolation reduction could keep the global average temperature constant, but global average precipitation would reduce, particularly in summer monsoon regions around the world. Temperature changes would also not be uniform; the tropics would cool, but high latitudes would warm, with continuing, but reduced sea ice and ice sheet melting. Temperature extremes would still increase, but not as much as without geoengineering. If geoengineering were halted all at once, there would be rapid temperature and precipitation increases at 5–10 times the rates from gradual global warming. The prospect of geoengineering working may reduce the current drive toward reducing greenhouse gas emissions, and there are concerns about commercial or military control. Because geoengineering cannot safely address climate change, global efforts to reduce greenhouse gas emissions and to adapt are crucial to address anthropogenic global warming.

  7. Stratospheric aerosol geoengineering

    International Nuclear Information System (INIS)

    Robock, Alan

    2015-01-01

    The Geoengineering Model Intercomparison Project, conducting climate model experiments with standard stratospheric aerosol injection scenarios, has found that insolation reduction could keep the global average temperature constant, but global average precipitation would reduce, particularly in summer monsoon regions around the world. Temperature changes would also not be uniform; the tropics would cool, but high latitudes would warm, with continuing, but reduced sea ice and ice sheet melting. Temperature extremes would still increase, but not as much as without geoengineering. If geoengineering were halted all at once, there would be rapid temperature and precipitation increases at 5–10 times the rates from gradual global warming. The prospect of geoengineering working may reduce the current drive toward reducing greenhouse gas emissions, and there are concerns about commercial or military control. Because geoengineering cannot safely address climate change, global efforts to reduce greenhouse gas emissions and to adapt are crucial to address anthropogenic global warming

  8. Stratospheric Aerosol Measurements

    Science.gov (United States)

    Pueschel, Rudolf, F.; Gore, Warren J. (Technical Monitor)

    1998-01-01

    Stratospheric aerosols affect the atmospheric energy balance by scattering and absorbing solar and terrestrial radiation. They also can alter stratospheric chemical cycles by catalyzing heterogeneous reactions which markedly perturb odd nitrogen, chlorine and ozone levels. Aerosol measurements by satellites began in NASA in 1975 with the Stratospheric Aerosol Measurement (SAM) program, to be followed by the Stratospheric Aerosol and Gas Experiment (SAGE) starting in 1979. Both programs employ the solar occultation, or Earth limb extinction, techniques. Major results of these activities include the discovery of polar stratospheric clouds (PSCs) in both hemispheres in winter, illustrations of the impacts of major (El Chichon 1982 and Pinatubo 1991) eruptions, and detection of a negative global trend in lower stratospheric/upper tropospheric aerosol extinction. This latter result can be considered a triumph of successful worldwide sulfur emission controls. The SAGE record will be continued and improved by SAGE III, currently scheduled for multiple launches beginning in 2000 as part of the Earth Observing System (EOS). The satellite program has been supplemented by in situ measurements aboard the ER-2 (20 km ceiling) since 1974, and from the DC-8 (13 km ceiling) aircraft beginning in 1989. Collection by wire impactors and subsequent electron microscopic and X-ray energy-dispersive analyses, and optical particle spectrometry have been the principle techniques. Major findings are: (1) The stratospheric background aerosol consists of dilute sulfuric acid droplets of around 0.1 micrometer modal diameter at concentration of tens to hundreds of monograms per cubic meter; (2) Soot from aircraft amounts to a fraction of one percent of the background total aerosol; (3) Volcanic eruptions perturb the sulfuric acid, but not the soot, aerosol abundance by several orders of magnitude; (4) PSCs contain nitric acid at temperatures below 195K, supporting chemical hypotheses

  9. A stratospheric aerosol increase

    Science.gov (United States)

    Rosen, J. M.; Hofmann, D. J.

    1980-01-01

    Large disturbances were noted in the stratospheric aerosol content in the midlatitude Northern Hemisphere commencing about 7 months after the eruption of La Soufriere and less than 1 month after the eruption of Sierra Negra. The aerosol was characterized by a very steep size distribution in the 0.15 to 0.25 micron radius range and contained a volatile component. Measurements near the equator and at the South Pole indicate that the disturbance was widespread. These observations were made before the May 18 eruption of Mt. St. Helens.

  10. Stratospheric aerosols and precursor gases

    Science.gov (United States)

    1982-01-01

    Measurements were made of the aerosol size, height and geographical distribution, their composition and optical properties, and their temporal variation with season and following large volcanic eruptions. Sulfur-bearing gases were measured in situ in the stratosphere, and studied of the chemical and physical processes which control gas-to-particle conversion were carried out in the laboratory.

  11. Laboratory studies of stratospheric aerosol chemistry

    Science.gov (United States)

    Molina, Mario J.

    1996-01-01

    In this report we summarize the results of the two sets of projects funded by the NASA grant NAG2-632, namely investigations of various thermodynamic and nucleation properties of the aqueous acid system which makes up stratospheric aerosols, and measurements of reaction probabilities directly on ice aerosols with sizes corresponding to those of polar stratospheric cloud particles. The results of these investigations are of importance for the assessment of the potential stratospheric effects of future fleets of supersonic aircraft. In particular, the results permit to better estimate the effects of increased amounts of water vapor and nitric acid (which forms from nitrogen oxides) on polar stratospheric clouds and on the chemistry induced by these clouds.

  12. The boiling point of stratospheric aerosols.

    Science.gov (United States)

    Rosen, J. M.

    1971-01-01

    A photoelectric particle counter was used for the measurement of aerosol boiling points. The operational principle involves raising the temperature of the aerosol by vigorously heating a portion of the intake tube. At or above the boiling point, the particles disintegrate rather quickly, and a noticeable effect on the size distribution and concentration is observed. Stratospheric aerosols appear to have the same volatility as a solution of 75% sulfuric acid. Chemical analysis of the aerosols indicates that there are other substances present, but that the sulfate radical is apparently the major constituent.

  13. Correlative measurements of the stratospheric aerosols

    Science.gov (United States)

    Santer, R.; Brogniez, C.; Herman, M.; Diallo, S.; Ackerman, M.

    1992-12-01

    Joint experiments were organized or available during stratospheric flights of a photopolarimeter, referred to as RADIBAL (radiometer balloon). In May 1984, RADIBAL flew simultaneously with another balloonborne experiment conducted by the Institut d'Aeronomie Spatiale de Belgique (IASB), which provides multiwavelength vertical profiles of the aerosol scattering coefficient. At this time, the El Chichon layer was observable quite directly from mountain sites. A ground-based station set up at Pic du Midi allowed an extensive description of the aerosol optical properties. The IASB and the Pic du Midi observations are consistent with the aerosol properties derived from the RADIBAL measurement analysis.

  14. Study of photolytic aerosols at stratospheric pressures

    International Nuclear Information System (INIS)

    Delattre, Patrick.

    1975-07-01

    An experimental study of photolytic aerosol formation at stratospheric pressure (60 Torr) and laboratory temperature, was carried out previous to the exact simulation of photolytic aerosol formation in real stratospheric conditions. An experimental simulation device, techniques of generation of known mixtures of inert gases with SO 2 and NOsub(x) traces at low concentration (below 1 ppm volume) and H 2 O traces (a few ppm), and techniques for the determination and counting of aerosol particles at low pressures were perfected. The following results were achieved: the rate of vapor condensation on nuclei was reduced when total pressure decreased. At low pressure the working of condensation nuclei counters and the formation of photolytic aerosols is influenced by this phenomenon. An explanation is proposed, as well as means to avoid this unpleasant effect on the working of nuclei counters at low pressure. No photolytic aerosol production was ascertained at 60 Torr when water concentration was below 100 ppm whatever the concentration of SO 2 or NOsub(x) traces. With water concentration below 1200ppm and SO 2 trace concentration below 1ppm, the aerosol particles produced could not consist of sulfuric acid drops but probably of nitrosyl sulfate acide crystals [fr

  15. Stratospheric Aerosol and Gas Experiment (SAGE) IV Pathfinder

    Data.gov (United States)

    National Aeronautics and Space Administration — The Clean Air Act mandates NASA to monitor stratospheric ozone, and stratospheric aerosol measurements are vital to our understanding of climate.  Maintaining...

  16. Satellite studies of the stratospheric aerosol

    International Nuclear Information System (INIS)

    McCormick, M.P.; Hamill, P.; Pepin, T.J.; Chu, W.P.; Swissler, T.J.; McMaster, L.R.

    1979-01-01

    The potential climatological and environmental importance of the stratospheric aerosol layer has prompted great interest in measuring the properties of this aerosol. In this paper we report on two recently deployed NASA satellite systems (SAM II and SAGE) that are monitoring the stratospheric aerosol. The satellite orbits are such that nearly global coverage is obtained. The instruments mounted in the spacecraft are sun photometers that measure solar intensity at specific wavelengths as it is moderated by atmospheric particulates and gases during each sunrise and sunset encountered by the satellites. The data obtained are ''inverted'' to yield vertical aerosol and gaseous (primarily ozone) extinction profiles with 1 km vertical resolution. Thus, latitudinal, longitudinal, and temporal variations in the aerosol layer can be evaluated. The satellite systems are being validated by a series of ground truth experiments using airborne and ground lidar, balloon-borne dustsondes, aircraft-mounted impactors, and other correlative sensors. We describe the SAM II and SAGE satellite systems, instrument characteristics, and mode of operation; outline the methodology of the experiments; and describe the ground truth experiments. We present preliminary results from these measurements

  17. Influence of stratospheric aerosol on albedo

    Energy Technology Data Exchange (ETDEWEB)

    Gormatyuk, Yu K; Kaufman, Yu G; Kolomeev, M P

    1985-06-01

    The influence of stratospheric aerosol (SA) on the transfer of solar radiation in the atmosphere is the principal factor determining the effect of SA on climate. The change in the radiation balance under the influence of SA is computed most precisely in radiative-convective models. However, the complex method used in these models cannot be used for other types of climate models. The objective of the study was to obtain a quantitative evaluation of the influence of SA on albedo without the use of simplifying assumptions. In the approximation of single scattering an expression is derived for change in albedo under the influence of stratospheric aerosol taking into account the dependence of albedo of the atmosphere-earth's surface system on solar zenith distance. The authors give the results of computations of the response of mean annual albedo to sulfuric acid aerosol for 10/sup 0/ latitude zones in the Northern Hemisphere. Specifically, computations of the optical characteristics of aerosol were made using the Mie theory for 10 spectral intervals taking in the range of wavelengths of solar radiation from 0.29 to 4.0 ..mu.. m. The refractive index of aerosol was stipulated in accordance with Palmer and Williams. The angular dependence of albedo for cloudless and cloudy atmospheres given by Harshvardhan was used. The values of undisturbed albedo were assumed to be identical for all wavelengths due to lack of climatological data on the spectral dependence of albedo of the atmosphere-earth's surface system. The angular distribution of the intensity of solar radiation for each of the latitude zones was computed by the method described by I.M. Alekseyev, et al.

  18. International Workshop on Stratospheric Aerosols: Measurements, Properties, and Effects

    Science.gov (United States)

    Pueschel, Rudolf F. (Editor)

    1991-01-01

    Following a mandate by the International Aerosol Climatology Program under the auspices of International Association of Meteorology and Atmospheric Physics International Radiation Commission, 45 scientists from five nations convened to discuss relevant issues associated with the measurement, properties, and effects of stratospheric aerosols. A summary is presented of the discussions on formation and evolution, transport and fate, effects on climate, role in heterogeneous chemistry, and validation of lidar and satellite remote sensing of stratospheric aerosols. Measurements are recommended of the natural (background) and the volcanically enhanced aerosol (sulfuric acid and silica particles), the exhaust of shuttle, civil aviation and supersonic aircraft operations (alumina, soot, and ice particles), and polar stratospheric clouds (ice, condensed nitric and hydrochloric acids).

  19. Sulphur-rich volcanic eruptions and stratospheric aerosols

    Science.gov (United States)

    Rampino, M. R.; Self, S.

    1984-01-01

    Data from direct measurements of stratospheric optical depth, Greenland ice-core acidity, and volcanological studies are compared, and it is shown that relatively small but sulfur-rich volcanic eruptions can have atmospheric effects equal to or even greater than much larger sulfur-poor eruptions. These small eruptions are probably the most frequent cause of increased stratospheric aerosols. The possible sources of the excess sulfur released in these eruptions are discussed.

  20. Tibetan Plateau glacier and hydrological change under stratospheric aerosol injection

    Science.gov (United States)

    Ji, D.

    2017-12-01

    As an important inland freshwater resource, mountain glaciers are highly related to human life, they provide water for many large rivers and play a very important role in regional water cycles. The response of mountain glaciers to future climate change is a topic of concern especially to the many people who rely on glacier-fed rivers for purposes such as irrigation. Geoengineering by stratospheric aerosol injection is a method of offsetting the global temperature rise from greenhouse gases. How the geoengineering by stratospheric aerosol injection affects the mass balance of mountain glaciers and adjacent river discharge is little understood. In this study, we use regional climate model WRF and catchment-based river model CaMa-Flood to study the impacts of stratospheric aerosol injection to Tibetan Plateau glacier mass balance and adjacent river discharge. To facilitate mountain glacier mass balance study, we improve the description of mountain glacier in the land surface scheme of WRF. The improvements include: (1) a fine mesh nested in WRF horizontal grid to match the highly non-uniform spatial distribution of the mountain glaciers, (2) revising the radiation flux at the glacier surface considering the surrounding terrain. We use the projections of five Earth system models for CMIP5 rcp45 and GeoMIP G4 scenarios to drive the WRF and CaMa-Flood models. The G4 scenario, which uses stratospheric aerosols to reduce the incoming shortwave while applying the rcp4.5 greenhouse gas forcing, starts stratospheric sulfate aerosol injection at a rate of 5 Tg per year over the period 2020-2069. The ensemble projections suggest relatively slower glacier mass loss rates and reduced river discharge at Tibetan Plateau and adjacent regions under geoengineering scenario by stratospheric aerosol injection.

  1. Lidar observations and transfer of stratospheric aerosol over Tomsk in summer period

    Science.gov (United States)

    Novikov, P. V.; Cheremisin, A. A.; Marichev, V. N.; Barashkov, T. O.

    2015-11-01

    The analysis of the stratospheric aerosol origin was carried out by the method of Lagrangian particle trajectories. Stratospheric aerosol was registered by lidar sounding of atmosphere above Tomsk in 2008-2013 in summer time. The analysis of the results had shown that the aerosol content at altitudes of 13-125 km with maximum at 16-18 km can be associated with aerosol transfer from tropical stratospheric reservoir.

  2. SAGE measurements of the stratospheric aerosol dispersion and loading from the Soufriere Volcano

    Science.gov (United States)

    Mccormick, M. P.; Kent, G. S.; Yue, G. K.; Cunnold, D. M.

    1981-01-01

    Explosions of the Soufriere volcano on the Caribbean Island of St. Vincent reduced two major stratospheric plumes which the stratospheric aerosol and gas experiment (SAGE) satellite tracked to West Africa and the North Atlantic Ocean. The total mass of the stratospheric ejecta measured is less than 0.5% of the global stratospheric aerosol burden. No significant temperature or climate perturbation is expected. It is found that the movement and dispersion of the plumes agree with those deduced from high altitude meteorological data and dispersion theory. The stratospheric aerosol dispersion and loading from the Soufrier volcano was measured.

  3. Possible effect of strong solar energetic particle events on polar stratospheric aerosol: a summary of observational results

    International Nuclear Information System (INIS)

    Mironova, I A; Usoskin, I G

    2014-01-01

    This letter presents a summary of a phenomenological study of the response of the polar stratosphere to strong solar energetic particle (SEP) events corresponding to ground level enhancements (GLEs) of cosmic rays. This work is focused on evaluation of the possible influence of the atmospheric ionization caused by SEPs upon formation of aerosol particles in the stratosphere over polar regions. Following case studies of two major SEP/GLE events, in January 2005 and September 1989, and their possible effects on polar stratospheric aerosols, we present here the results of an analysis of variations of the daily profiles of the stratospheric aerosol parameters (aerosol extinction for different wavelengths, as well as Ångstrom exponent) for both polar hemispheres during SEP/GLE events of July 2000, April 2001 and October 2003, which form already five clear cases corresponding to extreme and strong SEP/GLE events. The obtained results suggest that an enhancement of ionization rate by a factor of about two in the polar region with night/cold/winter conditions can lead to the formation/growing of aerosol particles in the altitude range of 10–25 km. We also present a summary of the investigated effects based on the phenomenological study of the atmospheric application of extreme SEP events. (paper)

  4. Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols

    KAUST Repository

    Kravitz, Ben

    2009-07-28

    We used a general circulation model of Earth\\'s climate to conduct geoengineering experiments involving stratospheric injection of sulfur dioxide and analyzed the resulting deposition of sulfate. When sulfur dioxide is injected into the tropical or Arctic stratosphere, the main additional surface deposition of sulfate occurs in midlatitude bands, because of strong cross-tropopause flux in the jet stream regions. We used critical load studies to determine the effects of this increase in sulfate deposition on terrestrial ecosystems by assuming the upper limit of hydration of all sulfate aerosols into sulfuric acid. For annual injection of 5 Tg of SO2 into the tropical stratosphere or 3 Tg of SO2 into the Arctic stratosphere, neither the maximum point value of sulfate deposition of approximately 1.5 mEq m−2 a−1 nor the largest additional deposition that would result from geoengineering of approximately 0.05 mEq m−2 a−1 is enough to negatively impact most ecosystems.

  5. Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols

    KAUST Repository

    Kravitz, Ben; Robock, Alan; Oman, Luke; Stenchikov, Georgiy L.; Marquardt, Allison B.

    2009-01-01

    We used a general circulation model of Earth's climate to conduct geoengineering experiments involving stratospheric injection of sulfur dioxide and analyzed the resulting deposition of sulfate. When sulfur dioxide is injected into the tropical or Arctic stratosphere, the main additional surface deposition of sulfate occurs in midlatitude bands, because of strong cross-tropopause flux in the jet stream regions. We used critical load studies to determine the effects of this increase in sulfate deposition on terrestrial ecosystems by assuming the upper limit of hydration of all sulfate aerosols into sulfuric acid. For annual injection of 5 Tg of SO2 into the tropical stratosphere or 3 Tg of SO2 into the Arctic stratosphere, neither the maximum point value of sulfate deposition of approximately 1.5 mEq m−2 a−1 nor the largest additional deposition that would result from geoengineering of approximately 0.05 mEq m−2 a−1 is enough to negatively impact most ecosystems.

  6. Effects of stratospheric aerosol surface processes on the LLNL two-dimensional zonally averaged model

    International Nuclear Information System (INIS)

    Connell, P.S.; Kinnison, D.E.; Wuebbles, D.J.; Burley, J.D.; Johnston, H.S.

    1992-01-01

    We have investigated the effects of incorporating representations of heterogeneous chemical processes associated with stratospheric sulfuric acid aerosol into the LLNL two-dimensional, zonally averaged, model of the troposphere and stratosphere. Using distributions of aerosol surface area and volume density derived from SAGE 11 satellite observations, we were primarily interested in changes in partitioning within the Cl- and N- families in the lower stratosphere, compared to a model including only gas phase photochemical reactions

  7. Stratospheric aerosol effects from Soufriere Volcano as measured by the SAGE satellite system

    Science.gov (United States)

    Mccormick, M. P.; Kent, G. S.; Yue, G. K.; Cunnold, D. M.

    1982-01-01

    During its April 1979 eruption series, Soufriere Volcano produced two major stratospheric plumes that the SAGE (Stratospheric Aerosol and Gas Experiment) satellite system tracked to West Africa and the North Atlantic Ocean. The total mass of these plumes, whose movement and dispersion are in agreement with those deduced from meteorological data and dispersion theory, was less than 0.5 percent of the global stratospheric aerosol burden; no significant temperature or climate perturbation is therefore expected.

  8. Global two-channel AVHRR aerosol climatology: effects of stratospheric aerosols and preliminary comparisons with MODIS and MISR retrievals

    International Nuclear Information System (INIS)

    Geogdzhayev, Igor V.; Mishchenko, Michael I.; Liu Li; Remer, Lorraine

    2004-01-01

    We present an update on the status of the global climatology of the aerosol column optical thickness and Angstrom exponent derived from channel-1 and -2 radiances of the Advanced Very High Resolution Radiometer (AVHRR) in the framework of the Global Aerosol Climatology Project (GACP). The latest version of the climatology covers the period from July 1983 to September 2001 and is based on an adjusted value of the diffuse component of the ocean reflectance as derived from extensive comparisons with ship sun-photometer data. We use the updated GACP climatology and Stratospheric Aerosol and Gas Experiment (SAGE) data to analyze how stratospheric aerosols from major volcanic eruptions can affect the GACP aerosol product. One possible retrieval strategy based on the AVHRR channel-1 and -2 data alone is to infer both the stratospheric and the tropospheric aerosol optical thickness while assuming fixed microphysical models for both aerosol components. The second approach is to use the SAGE stratospheric aerosol data in order to constrain the AVHRR retrieval algorithm. We demonstrate that the second approach yields a consistent long-term record of the tropospheric aerosol optical thickness and Angstrom exponent. Preliminary comparisons of the GACP aerosol product with MODerate resolution Imaging Spectrometer (MODIS) and Multiangle Imaging Spectro-Radiometer aerosol retrievals show reasonable agreement, the GACP global monthly optical thickness being lower than the MODIS one by approximately 0.03. Larger differences are observed on a regional scale. Comparisons of the GACP and MODIS Angstrom exponent records are less conclusive and require further analysis

  9. Mechanism and Kinetics of the Formation and Transport of Aerosol Particles in the Lower Stratosphere

    Science.gov (United States)

    Aloyan, A. E.; Ermakov, A. N.; Arutyunyan, V. O.

    2018-03-01

    Field and laboratory observation data on aerosol particles in the lower stratosphere are considered. The microphysics of their formation, mechanisms of heterogeneous chemical reactions involving reservoir gases (e.g., HCl, ClONO2, etc.) and their kinetic characteristics are analyzed. A new model of global transport of gaseous and aerosol admixtures in the lower stratosphere is described. The preliminary results from a numerical simulation of the formation of sulfate particles of the Junge layer and particles of polar stratospheric clouds (PSCs, types Ia, Ib, and II) are presented, and their effect on the gas and aerosol composition is analyzed.

  10. Long Term Stratospheric Aerosol Lidar Measurements in Kyushu

    Science.gov (United States)

    Fujiwara, Motowo

    1992-01-01

    Lidar soundings of the stratospheric aerosols have been made since 1972 at Fukuoka, Kyushu Island of Japan. Volcanic clouds from eruptions of La Soufriere, Sierra Negra, St. Helens, Uluwan, Alaid, unknown volcano, and El Chichon were detected one after another in only three years from 1979 to 1982. In july 1991 strong scattering layers which were originated from the serious eruptions of Pinatubo in June and were almost comparable to the El Chichon clouds were detected. Volcanic clouds from pinatubo and other volcanos mentioned are examined and carefully compared to each other and to the wind and temperature which was measured by Fukuoka Meteorological Observatory almost at the same time as the lidar observation was made.

  11. Small volcanic eruptions and the stratospheric sulfate aerosol burden

    Science.gov (United States)

    Pyle, David M.

    2012-09-01

    Understanding of volcanic activity and its impacts on the atmosphere has evolved in discrete steps, associated with defining eruptions. The eruption of Krakatau, Indonesia, in August 1883 was the first whose global reach was recorded through observations of atmospheric phenomena around the world (Symons 1888). The rapid equatorial spread of Krakatau's ash cloud revealed new details of atmospheric circulation, while the vivid twilights and other optical phenomena were soon causally linked to the effects of particles and gases released from the volcano (e.g. Stothers 1996, Schroder 1999, Hamilton 2012). Later, eruptions of Agung, Bali (1963), El Chichón, Mexico (1982) and Pinatubo, Philippines (1991) led to a fuller understanding of how volcanic SO2 is transformed to a long-lived stratospheric sulfate aerosol, and its consequences (e.g. Meinel and Meinel 1967, Rampino and Self 1982, Hoffman and Rosen 1983, Bekki and Pyle 1994, McCormick et al 1995). While our ability to track the dispersal of volcanic emissions has been transformed since Pinatubo, with the launch of fleets of Earth-observing satellites (e.g. NASA's A-Train; ESA's MetOp) and burgeoning networks of ground-based remote-sensing instruments (e.g. lidar and sun-photometers; infrasound and lightning detection systems), there have been relatively few significant eruptions. Thus, there have been limited opportunities to test emerging hypotheses including, for example, the vexed question of the role of 'smaller' explosive eruptions in perturbations of the atmosphere—those that may just be large enough to reach the stratosphere (of size 'VEI 3', Newhall and Self 1982, Pyle 2000). Geological evidence, from ice-cores and historical eruptions, suggests that small explosive volcanic eruptions with the potential to transport material into the stratosphere should be frequent (5-10 per decade), and responsible for a significant proportion of the long-term time-averaged flux of volcanic sulfur into the stratosphere

  12. Efficient transport of tropospheric aerosol into the stratosphere via the Asian summer monsoon anticyclone

    Science.gov (United States)

    Yu, Pengfei; Rosenlof, Karen H.; Liu, Shang; Telg, Hagen; Thornberry, Troy D.; Rollins, Andrew W.; Portmann, Robert W.; Bai, Zhixuan; Ray, Eric A.; Duan, Yunjun; Pan, Laura L.; Toon, Owen B.; Bian, Jianchun; Gao, Ru-Shan

    2017-07-01

    An enhanced aerosol layer near the tropopause over Asia during the June-September period of the Asian summer monsoon (ASM) was recently identified using satellite observations. Its sources and climate impact are presently not well-characterized. To improve understanding of this phenomenon, we made in situ aerosol measurements during summer 2015 from Kunming, China, then followed with a modeling study to assess the global significance. The in situ measurements revealed a robust enhancement in aerosol concentration that extended up to 2 km above the tropopause. A climate model simulation demonstrates that the abundant anthropogenic aerosol precursor emissions from Asia coupled with rapid vertical transport associated with monsoon convection leads to significant particle formation in the upper troposphere within the ASM anticyclone. These particles subsequently spread throughout the entire Northern Hemispheric (NH) lower stratosphere and contribute significantly (˜15%) to the NH stratospheric column aerosol surface area on an annual basis. This contribution is comparable to that from the sum of small volcanic eruptions in the period between 2000 and 2015. Although the ASM contribution is smaller than that from tropical upwelling (˜35%), we find that this region is about three times as efficient per unit area and time in populating the NH stratosphere with aerosol. With a substantial amount of organic and sulfur emissions in Asia, the ASM anticyclone serves as an efficient smokestack venting aerosols to the upper troposphere and lower stratosphere. As economic growth continues in Asia, the relative importance of Asian emissions to stratospheric aerosol is likely to increase.

  13. Lidar measurements of ozone and aerosol distributions during the 1992 airborne Arctic stratospheric expedition

    Science.gov (United States)

    Browell, Edward V.; Butler, Carolyn F.; Fenn, Marta A.; Grant, William B.; Ismail, Syed; Carter, Arlen F.

    1994-01-01

    The NASA Langley airborne differential absorption lidar system was operated from the NASA Ames DC-8 aircraft during the 1992 Airborne Arctic Stratospheric Expedition to investigate the distribution of stratospheric aerosols and ozone (O3) across the Arctic vortex from January to March 1992. Aerosols from the Mt. Pinatubo eruption were found outside and inside the Arctic vortex with distinctly different scattering characteristics and spatial distributions in the two regions. The aerosol and O3 distributions clearly identified the edge of the vortex and provided additional information on vortex dynamics and transport processes. Few polar stratospheric clouds were observed during the AASE-2; however, those that were found had enhanced scattering and depolarization over the background Pinatubo aerosols. The distribution of aerosols inside the vortex exhibited relatively minor changes during the AASE-2. Ozone depletion inside the vortex as limited to less than or equal to 20 percent in the altitude region from 15-20 km.

  14. Extended observations of volcanic SO2 and sulfate aerosol in the stratosphere

    NARCIS (Netherlands)

    Carn, S.A.; Krotkov, N.A.; Yang, Kai; Hoff, R.M.; Prata, A.J.; Krueger, A.J.; Loughlin, S.C.; Levelt, P.F.

    2007-01-01

    Sulfate aerosol produced after injection of sulfur dioxide (SO2) into the stratosphere by volcanic eruptions can trigger climate change. We present new satellite data from the Ozone Monitoring Instrument (OMI) and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) missions

  15. Influence of Aerosol Heating on the Stratospheric Transport of the Mt. Pinatubo Eruption

    Science.gov (United States)

    Aquila, Valentina; Oman, Luke D.; Stolarski, Richard S.

    2011-01-01

    On June 15th, 1991 the eruption of Mt. Pinatubo (15.1 deg. N, 120.3 Deg. E) in the Philippines injected about 20 Tg of sulfur dioxide in the stratosphere, which was transformed into sulfuric acid aerosol. The large perturbation of the background aerosol caused an increase in temperature in the lower stratosphere of 2-3 K. Even though stratospheric winds climatological]y tend to hinder the air mixing between the two hemispheres, observations have shown that a large part of the SO2 emitted by Mt. Pinatubo have been transported from the Northern to the Southern Hemisphere. We simulate the eruption of Mt. Pinatubo with the Goddard Earth Observing System (GEOS) version 5 global climate model, coupled to the aerosol module GOCART and the stratospheric chemistry module StratChem, to investigate the influence of the eruption of Mt. Pinatubo on the stratospheric transport pattern. We perform two ensembles of simulations: the first ensemble consists of runs without coupling between aerosol and radiation. In these simulations the plume of aerosols is treated as a passive tracer and the atmosphere is unperturbed. In the second ensemble of simulations aerosols and radiation are coupled. We show that the set of runs with interactive aerosol produces a larger cross-equatorial transport of the Pinatubo cloud. In our simulations the local heating perturbation caused by the sudden injection of volcanic aerosol changes the pattern of the stratospheric winds causing more intrusion of air from the Northern into the Southern Hemisphere. Furthermore, we perform simulations changing the injection height of the cloud, and study the transport of the plume resulting from the different scenarios. Comparisons of model results with SAGE II and AVHRR satellite observations will be shown.

  16. Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS)

    Science.gov (United States)

    Gasbarre, Joseph; Walker, Richard; Cisewski, Michael; Zawodny, Joseph; Cheek, Dianne; Thornton, Brooke

    2015-01-01

    The Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) mission will extend the SAGE data record from the ideal vantage point of the International Space Station (ISS). The ISS orbital inclination is ideal for SAGE measurements providing coverage between 70 deg north and 70 deg south latitude. The SAGE data record includes an extensively validated data set including aerosol optical depth data dating to the Stratospheric Aerosol Measurement (SAM) experiments in 1975 and 1978 and stratospheric ozone profile data dating to the Stratospheric Aerosol and Gas Experiment (SAGE) in 1979. These and subsequent data records, notably from the SAGE II experiment launched on the Earth Radiation Budget Satellite in 1984 and the SAGE III experiment launched on the Russian Meteor-3M satellite in 2001, have supported a robust, long-term assessment of key atmospheric constituents. These scientific measurements provide the basis for the analysis of five of the nine critical constituents (aerosols, ozone (O3), nitrogen dioxide (NO2), water vapor (H2O), and air density using O2) identified in the U.S. National Plan for Stratospheric Monitoring. SAGE III on ISS was originally scheduled to fly on the ISS in the same timeframe as the Meteor-3M mission, but was postponed due to delays in ISS construction. The project was re-established in 2009.

  17. Characteristics of Volcanic Stratospheric Aerosol Layer Observed by CALIOP and Ground Based Lidar at Equatorial Atmosphere Radar Site

    Science.gov (United States)

    Abo, Makoto; Shibata, Yasukuni; Nagasawa, Chikao

    2018-04-01

    We investigated the relation between major tropical volcanic eruptions in the equatorial region and the stratospheric aerosol data, which have been collected by the ground based lidar observations at at Equatorial Atmosphere Radar site between 2004 and 2015 and the CALIOP observations in low latitude between 2006 and 2015. We found characteristic dynamic behavior of volcanic stratospheric aerosol layers over equatorial region.

  18. Volcanic eruptions and the increases in the stratospheric aerosol content: Lidar measurements from 1982 to 1986

    Science.gov (United States)

    Hayashida, S.; Iikura, Y.; Shimizu, H.; Sasano, Y.; Nakane, H.; Sugimoto, N.; Matsui, I.; Takeuchi, N.

    1986-01-01

    The results of the observation for stratospheric aerosols which were carried out since the autumn of 1982 by using the NIES large lidar are described. Specifications of the lidar system are shown. The lidar has two wavelenghts of 1.06 and 0.53 micrometers. The 0.53 micrometer is mainly used for the stratospheric aerosols, because the PMT for 0.53 micrometers has higher sensitivity that that for 1.06 micrometers and the total efficiency is higher in the former. A switching circuit is used to control the PMT gain for avoiding signal induced noise in PMT. For the last four years, the stratospheric aerosol layer which was significantly perturbed by the El Chichon volcanic eruption was observed. The scattering ratio profiles observed from 1982 through 1983 are given.

  19. Lidar observations of stratospheric aerosol layer after the Mt. Pinatubo volcanic eruption

    International Nuclear Information System (INIS)

    Nagai, Tomohiro; Uchino, Osamu; Fujimoto, Toshifumi.

    1992-01-01

    The volcano Mt. Pinatubo located on the Luzon Island, Philippines, had explosively erupted on June 15, 1991. The volcanic eruptions such as volcanic ash, SO2 and H2O reached into the stratosphere over 30 km altitude by the NOAA-11 satellite observation and this is considered one of the biggest volcanic eruptions in this century. A grandiose volcanic eruption influences the atmosphere seriously and causes many climatic effects globally. There had been many impacts on radiation, atmospheric temperature and stratospheric ozone after some past volcanic eruptions. The main cause of volcanic influence depends on stratospheric aerosol, that stay long enough to change climate and other meteorological conditions. Therefore it is very important to watch stratospheric aerosol layers carefully and continuously. Standing on this respect, we do not only continue stratospheric aerosol observation at Tsukuba but also have urgently developed another lidar observational point at Naha in Okinawa Island. This observational station could be thought valuable since there is no lidar observational station in this latitudinal zone and it is much nearer to Mt. Pinatubo. Especially, there is advantage to link up these two stations on studying the transportation mechanism in the stratosphere. In this paper, we present the results of lidar observations at Tsukuba and Naha by lidar systems with Nd:YAG laser

  20. Lidar Observations of Stratospheric Aerosol Layer After the Mt. Pinatubo Volcanic Eruption

    Science.gov (United States)

    Nagai, Tomohiro; Uchino, Osamu; Fujimoto, Toshifumi

    1992-01-01

    The volcano Mt. Pinatubo located on the Luzon Island, Philippines, had explosively erupted on June 15, 1991. The volcanic eruptions such as volcanic ash, SO2 and H2O reached into the stratosphere over 30 km altitude by the NOAA-11 satellite observation and this is considered one of the biggest volcanic eruptions in this century. A grandiose volcanic eruption influences the atmosphere seriously and causes many climatic effects globally. There had been many impacts on radiation, atmospheric temperature and stratospheric ozone after some past volcanic eruptions. The main cause of volcanic influence depends on stratospheric aerosol, that stay long enough to change climate and other meteorological conditions. Therefore it is very important to watch stratospheric aerosol layers carefully and continuously. Standing on this respect, we do not only continue stratospheric aerosol observation at Tsukuba but also have urgently developed another lidar observational point at Naha in Okinawa Island. This observational station could be thought valuable since there is no lidar observational station in this latitudinal zone and it is much nearer to Mt. Pinatubo. Especially, there is advantage to link up these two stations on studying the transportation mechanism in the stratosphere. In this paper, we present the results of lidar observations at Tsukuba and Naha by lidar systems with Nd:YAG laser.

  1. Aerosol particle size distribution in the stratosphere retrieved from SCIAMACHY limb measurements

    Science.gov (United States)

    Malinina, Elizaveta; Rozanov, Alexei; Rozanov, Vladimir; Liebing, Patricia; Bovensmann, Heinrich; Burrows, John P.

    2018-04-01

    health, stratospheric aerosol plays an important role in atmospheric chemistry and climate change. In particular, information about the amount and distribution of stratospheric aerosols is required to initialize climate models, as well as validate aerosol microphysics models and investigate geoengineering. In addition, good knowledge of stratospheric aerosol loading is needed to increase the retrieval accuracy of key trace gases (e.g. ozone or water vapour) when interpreting remote sensing measurements of the scattered solar light. The most commonly used characteristics to describe stratospheric aerosols are the aerosol extinction coefficient and Ångström coefficient. However, the use of particle size distribution parameters along with the aerosol number density is a more optimal approach. In this paper we present a new retrieval algorithm to obtain the particle size distribution of stratospheric aerosol from space-borne observations of the scattered solar light in the limb-viewing geometry. While the mode radius and width of the aerosol particle size distribution are retrieved, the aerosol particle number density profile remains unchanged. The latter is justified by a lower sensitivity of the limb-scattering measurements to changes in this parameter. To our knowledge this is the first data set providing two parameters of the particle size distribution of stratospheric aerosol from space-borne measurements of scattered solar light. Typically, the mode radius and w can be retrieved with an uncertainty of less than 20 %. The algorithm was successfully applied to the tropical region (20° N-20° S) for 10 years (2002-2012) of SCIAMACHY observations in limb-viewing geometry, establishing a unique data set. Analysis of this new climatology for the particle size distribution parameters showed clear increases in the mode radius after the tropical volcanic eruptions, whereas no distinct behaviour of the absolute distribution width could be identified. A tape recorder

  2. Odin-OSIRIS stratospheric aerosol data product and SAGE III intercomparison

    Directory of Open Access Journals (Sweden)

    A. E. Bourassa

    2012-01-01

    Full Text Available The scattered sunlight measurements made by the Optical Spectrograph and InfraRed Imaging System (OSIRIS on the Odin spacecraft are used to retrieve vertical profiles of stratospheric aerosol extinction at 750 nm. The recently released OSIRIS Version 5 data product contains the first publicly released stratospheric aerosol extinction retrievals, and these are now available for the entire Odin mission, which extends from the present day back to launch in 2001. A proof-of-concept study for the retrieval of stratospheric aerosol extinction from limb scatter measurements was previously published and the Version 5 data product retrievals are based on this work, but incorporate several important improvements to the algorithm. One of the primary changes is the use of a new retrieval vector that greatly improves the sensitivity to aerosol scattering by incorporating a forward modeled calculation of the radiance from a Rayleigh atmosphere. Additional improvements include a coupled retrieval of the effective albedo, a new method for normalization of the retrieval vector to improve signal-to-noise, and the use of an initial guess that is representative of very low background aerosol loading conditions, which allows for maximal retrieval range. Furthermore, the Version 5 data set is compared to Stratospheric Aerosol and Gas Experiment (SAGE III 755 nm extinction profiles during the almost four years of mission overlap from 2002 to late 2005. The vertical structure in coincident profile measurements is well correlated and the statistics on a relatively large set of tight coincident measurements show agreement between the measurements from the two instruments to within approximately 10% throughout the 15 to 25 km altitude range, which covers the bulk of the stratospheric aerosol layer for the mid and high latitude cases studied here.

  3. Toward a Combined SAGE II-HALOE Aerosol Climatology: An Evaluation of HALOE Version 19 Stratospheric Aerosol Extinction Coefficient Observations

    Science.gov (United States)

    Thomason, L. W.

    2012-01-01

    Herein, the Halogen Occultation Experiment (HALOE) aerosol extinction coefficient data is evaluated in the low aerosol loading period after 1996 as the first necessary step in a process that will eventually allow the production of a combined HALOE/SAGE II (Stratospheric Aerosol and Gas Experiment) aerosol climatology of derived aerosol products including surface area density. Based on these analyses, it is demonstrated that HALOE's 3.46 microns is of good quality above 19 km and suitable for scientific applications above that altitude. However, it is increasingly suspect at lower altitudes and should not be used below 17 km under any circumstances after 1996. The 3.40 microns is biased by about 10% throughout the lower stratosphere due to the failure to clear NO2 but otherwise appears to be a high quality product down to 15 km. The 2.45 and 5.26 micron aerosol extinction coefficient measurements are clearly biased and should not be used for scientific applications after the most intense parts of the Pinatubo period. Many of the issues in the aerosol data appear to be related to either the failure to clear some interfering gas species or doing so poorly. For instance, it is clear that the 3.40micronaerosol extinction coefficient measurements can be improved through the inclusion of an NO2 correction and could, in fact, end up as the highest quality overall HALOE aerosol extinction coefficient measurement. It also appears that the 2.45 and 5.26 micron channels may be improved by updating the Upper Atmosphere Pilot Database which is used as a resource for the removal of gas species otherwise not available from direct HALOE measurements. Finally, a simple model to demonstrate the promise of mixed visible/infrared aerosol extinction coefficient ensembles for the retrieval of bulk aerosol properties demonstrates that a combined HALOE/SAGE II aerosol climatology is feasible and may represent a substantial improvement over independently derived data sets.

  4. Interpretation of DIAL Measurements of Lower Stratospheric Ozone in Regions with Pinatubo Aerosols

    Science.gov (United States)

    Grant, William B.; Browell, Edward V.; Fenn, Marta A.; Butler, Carolyn F.; Brackett, Vincent G.; Veiga, Robert E.; Mayor, Shane D.; Fishman, Jack; Nganga, D.; Minga, A.

    1992-01-01

    The influence of volcanic aerosols on stratospheric ozone is a topic of current interest, especially with the June 15, 1991 eruption of Mt. Pinatubo in the Philippines. Lidar has been used in the past to provide aerosol profiles which could be compared with ozone profiles measured using ozonesondes to look for coincidences between volcanic aerosols and ozone decreases. The differential absorption lidar (DIAL) technique has the advantages of being able to measure ozone and aerosol profiles simultaneously as well as being able to cover large geographical regions rapidly. While there are problems associated with correcting the ozone profiles for the presence of aerosols, the corrections can be made reliably when the wavelengths are closely spaced and the Bernoulli method is applied. The DIAL measurements considered in this paper are those obtained in the tropical stratosphere in January 1992 during the Airborne Arctic Stratospheric Expedition (AASE-II). The determination of ozone profiles in the presence of Pinatubo aerosols is discussed in a companion paper.

  5. Measurements of stratospheric Pinatubo aerosol extinction profiles by a Raman lidar

    International Nuclear Information System (INIS)

    Abo, Makoto; Nagasawa, Chikao.

    1992-01-01

    The Raman lidar has been used for remote measurements of water vapor, ozone and atmospheric temperature in the lower troposphere because the Raman cross section is three orders smaller than the Rayleigh cross section. The authors estimated the extinction coefficients of the Pinatubo volcanic aerosol in the stratosphere using a Raman lidar. If the precise aerosol extinction coefficients are derived, the backscatter coefficient of a Mie scattering lidar will be more accurately estimated. The Raman lidar has performed to measure density profiles of some species using Raman scattering. Here the authors used a frequency-doubled Nd:YAG laser for transmitter and received nitrogen vibrational Q-branch Raman scattering signal. Ansmann et al. (1990) derived tropospherical aerosol extinction profiles with a Raman lidar. The authors think that this method can apply to dense stratospheric aerosols such as Pinatubo volcanic aerosols. As dense aerosols are now accumulated in the stratosphere by Pinatubo volcanic eruption, the error of Ramen lidar signal regarding the fluctuation of air density can be ignored

  6. Development of the Multi-Angle Stratospheric Aerosol Radiometer (MASTAR) Instrument

    Science.gov (United States)

    DeLand, M. T.; Colarco, P. R.; Kowalewski, M. G.; Gorkavyi, N.; Ramos-Izquierdo, L.

    2017-12-01

    Aerosol particles in the stratosphere ( 15-25 km altitude), both produced naturally and perturbed by volcanic eruptions and anthropogenic emissions, continue to be a source of significant uncertainty in the Earth's energy budget. Stratospheric aerosols can offset some of the warming effects caused by greenhouse gases. These aerosols are currently monitored using measurements from the Ozone Mapping and Profiling Suite (OMPS) Limb Profiler (LP) instrument on the Suomi NPP satellite. In order to improve the sensitivity and spatial coverage of these aerosol data, we are developing an aerosol-focused compact version of the OMPS LP sensor called Multi-Angle Stratospheric Aerosol Radiometer (MASTAR) to fly on a 3U Cubesat satellite, using a NASA Instrument Incubator Program (IIP) grant. This instrument will make limb viewing measurements of the atmosphere in multiple directions simultaneously, and uses only a few selected wavelengths to reduce size and cost. An initial prototype version has been constructed using NASA GSFC internal funding and tested in the laboratory. Current design work is targeted towards a preliminary field test in Spring 2018. We will discuss the scientific benefits of MASTAR and the status of the project.

  7. Aerosol-associated changes in tropical stratospheric ozone following the eruption of Mount Pinatubo

    Science.gov (United States)

    Grant, William B.; Browell, Edward V.; Fishman, Jack; Brackett, Vincent G.; Veiga, Robert E.; Nganga, Dominique; Minga, A.; Cros, Bernard; Butler, Carolyn F.; Fenn, Marta A.

    1994-01-01

    The large amount of sulfuric acid aerosol formed in the stratosphere by conversion of sulfur dioxide emitted by the eruption of Mount Pinatubo (15.14 deg N, 120.35 deg E) in the Philippines around June 15, 1991, has had a pronounced effect on lower stratospheric ozone in the tropics. Measurements of stratospheric ozone in the tropics using electrochemical concentration cell (ECC) sondes before and after the eruption and the airborne UV differential absorption lidar (DIAL) system after the eruption are compared with Stratospheric Aerosol and Gas Experiment II (SAGE II) measurements from several years before the eruption and ECC sonde measurements from the year prior to the eruption to determine the resulting changes. Ozone decreases of up to 33 % compared with SAGE II climatological values were found to be directly correlated with altitude regions of enhanced aerosol loading in the 16- to 28-km range. A maximum partial-column decrease of 29 +/- Dobson units (DU) was found over the 16- to 28-km range in September 1991 along with small increases (to 5.9 +/- 2 DU) from 28 to 31.5 km. A large decrease of ozone was also found at 4 deg to 8 deg S from May to August 1992, with a maximum decrease of 33 +/- 7 DU found above Brazzaville in July. Aerosol data form the visible channel of the advanced very high resolution radiometer (AVHRR) and the visible wavelength of the UV DIAL system were used to examine the relationship between aerosol (surface area) densities and ozone changes. The tropical stratospheric ozone changes we observed in 1991 and 1992 are likely be explained by a combination of dynamical (vertical transport) perturbations, radiative perturbations on ozone photochemistry, and heterogeneous chemistry.

  8. Evidence of transport, sedimentation and coagulation mechanisms in the relaxation of post-volcanic stratospheric aerosols

    Directory of Open Access Journals (Sweden)

    D. Fussen

    2001-09-01

    Full Text Available Spatio-temporal distributions of stratospheric aerosols, measured by the ORA instrument from August 1992 until May 1993, are presented in the latitude range (40° S–40° N. Particle total number density, mode radius and distribution width are derived and interpreted. The respective roles of advection, sedimentation and coagulation are discussed. We also identify clear transport/sedimentation patterns and we show the enhancement of coagulation in stagnation regions. Efficient transport of aerosol particles up to 50 km is suggested.Key words. Atmospheric composition and structure (aerosols and particles; middle atmosphere-composition and chemistry; volcanic effects

  9. Volcanic-aerosol-induced changes in stratospheric ozone following the eruption of Mount Pinatubo

    Science.gov (United States)

    Grant, W. B.; Browell, E. V.; Fishman, J.; Brackett, V. G.; Fenn, M. A.; Butler, C. F.; Nganga, D.; Minga, A.; Cros, B.; Mayor, S. D.

    1994-01-01

    Measurements of lower stratospheric ozone in the Tropics using electrochemical concentrations cell (ECC) sondes and the airborne UV Differential Absorption Lidar (DIAL) system after the eruption of Mt. Pinatubo are compared with the Stratospheric Aerosol and Gas Experiment 2 (SAGE 2) and ECC sonde measurements from below the eruption to determine what changes have occurred as a result. Aerosol data from the Advanced Very High Resolution Radiometer (AVHRR) and the visible and IR wavelengths of the lidar system are used to examine the relationship between aerosols and ozone changes. Ozone decreases of 30 percent at altitudes between 19 and 26 km, partial column (16-28 km) decreases of about 27 D.U., and slight increases (5.4 D.U.) between 28 and 31 km are found in comparison with SAGE 2 climatological values.

  10. A sensitivity analysis of volcanic aerosol dispersion in the stratosphere. [Mt. Fuego, Guatemala eruptions

    Science.gov (United States)

    Butler, C. F.

    1979-01-01

    A computer sensitivity analysis was performed to determine the uncertainties involved in the calculation of volcanic aerosol dispersion in the stratosphere using a 2 dimensional model. The Fuego volcanic event of 1974 was used. Aerosol dispersion processes that were included are: transport, sedimentation, gas phase sulfur chemistry, and aerosol growth. Calculated uncertainties are established from variations in the stratospheric aerosol layer decay times at 37 latitude for each dispersion process. Model profiles are also compared with lidar measurements. Results of the computer study are quite sensitive (factor of 2) to the assumed volcanic aerosol source function and the large variations in the parameterized transport between 15 and 20 km at subtropical latitudes. Sedimentation effects are uncertain by up to a factor of 1.5 because of the lack of aerosol size distribution data. The aerosol chemistry and growth, assuming that the stated mechanisms are correct, are essentially complete in several months after the eruption and cannot explain the differences between measured and modeled results.

  11. The background aerosol in the lower stratosphere and the tropospheric aerosol in the Alps. Final report; Das Hintergrundaerosol der unteren Stratosphaere und das troposphaerische Aerosol der Alpen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, H.; Trickl, T.

    2001-06-04

    As a contribution to the German Aerosol-Lidar Network lidar backscatter measurements have been carried out at Garmisch-Partenkirchen in a wide range of the atmosphere from next to the ground to altitudes beyond 30 km. The investigations, on one hand, were devoted to establishing a climatology of the aerosol extinction coefficient for the northern Alps and to prolonging the long-term measurement series of the stratospheric aerosol. On the other hand, aerosol was used as a tracer of polluted air masses in atmospheric transport studies (orographically induced vertical transport, advection of Saharan dust, as well as aerosol advection from the North american boundary layer and from large-scale wild fire in the United States and Canada). These transport processes given the seasonal cycle of the aerosol throughout the troposphere. In the free troposphere a pronounced spring-time aerosol maximum was found. The stratospheric aerosol concentration had decayed to a background-type level during the reporting period. As a consequence, the influence of smaller aerosol contributions could be distinguished such as the eruption of the volcano Shishaldin (Alaska) and aircraft emissions. (orig.) [German] Im Rahmen des deutschen Aerosollidarnetzes wurden in Garmisch-Partenkirchen Lidar-Rueckstreumessungen in einem weiten Bereich der Atmosphaere von Bodennaehe bis in ueber 30 km Hoehe durchgefuehrt. Die Arbeiten dienten zum einen der Erstellung einer Klimatologie des Aerosol-Extinktionskoeffizienten fuer die Nordalpen sowie der Verlaengerung der seit 1976 erstellten Langzeitmessreihe des stratosphaerischen Aerosols. Zum anderen fanden atmosphaerische Transportstudien statt, bei denen das Aerosol als 'Tracer' fuer Luftverschmutzung verwendet wurde (orographisch induzierter Vertikaltransport, Advektion von Saharastaub und Aerosoladvektion aus der nordamerikanischen Genzschicht und von grossflaechigen Waldbraenden in den U.S.A. und Kanada). Diese Transportprozesse bestimmen den

  12. Major Influence of Tropical Volcanic Eruptions on the Stratospheric Aerosol Layer During the Last Decade

    Science.gov (United States)

    Vernier, Jean-Paul; Thomason, Larry W.; Pommereau, J.-P.; Bourassa, Adam; Pelon, Jacques; Garnier, Anne; Hauchecorne, A.; Blanot, L.; Trepte, Charles R.; Degenstein, Doug; hide

    2011-01-01

    The variability of stratospheric aerosol loading between 1985 and 2010 is explored with measurements from SAGE II, CALIPSO, GOMOS/ENVISAT, and OSIRIS/Odin space-based instruments. We find that, following the 1991 eruption of Mount Pinatubo, stratospheric aerosol levels increased by as much as two orders of magnitude and only reached background levels between 1998 and 2002. From 2002 onwards, a systematic increase has been reported by a number of investigators. Recently, the trend, based on ground-based lidar measurements, has been tentatively attributed to an increase of SO2 entering the stratosphere associated with coal burning in Southeast Asia. However, we demonstrate with these satellite measurements that the observed trend is mainly driven by a series of moderate but increasingly intense volcanic eruptions primarily at tropical latitudes. These events injected sulfur directly to altitudes between 18 and 20 km. The resulting aerosol particles are slowly lofted into the middle stratosphere by the Brewer-Dobson circulation and are eventually transported to higher latitudes.

  13. SAGE II Measurements of Stratospheric Aerosol Properties at Non-Volcanic Levels

    Science.gov (United States)

    Thomason, Larry W.; Burton, Sharon P.; Luo, Bei-Ping; Peter, Thomas

    2008-01-01

    Since 2000, stratospheric aerosol levels have been relatively stable and at the lowest levels observed in the historical record. Given the challenges of making satellite measurements of aerosol properties at these levels, we have performed a study of the sensitivity of the product to the major components of the processing algorithm used in the production of SAGE II aerosol extinction measurements and the retrieval process that produces the operational surface area density (SAD) product. We find that the aerosol extinction measurements, particularly at 1020 nm, remain robust and reliable at the observed aerosol levels. On the other hand, during background periods, the SAD operational product has an uncertainty of at least a factor of 2 during due to the lack of sensitivity to particles with radii less than 100 nm.

  14. A global space-based stratospheric aerosol climatology: 1979-2016

    Science.gov (United States)

    Thomason, Larry W.; Ernest, Nicholas; Millán, Luis; Rieger, Landon; Bourassa, Adam; Vernier, Jean-Paul; Manney, Gloria; Luo, Beiping; Arfeuille, Florian; Peter, Thomas

    2018-03-01

    We describe the construction of a continuous 38-year record of stratospheric aerosol optical properties. The Global Space-based Stratospheric Aerosol Climatology, or GloSSAC, provided the input data to the construction of the Climate Model Intercomparison Project stratospheric aerosol forcing data set (1979-2014) and we have extended it through 2016 following an identical process. GloSSAC focuses on the Stratospheric Aerosol and Gas Experiment (SAGE) series of instruments through mid-2005, and on the Optical Spectrograph and InfraRed Imager System (OSIRIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data thereafter. We also use data from other space instruments and from ground-based, air, and balloon borne instruments to fill in key gaps in the data set. The end result is a global and gap-free data set focused on aerosol extinction coefficient at 525 and 1020 nm and other parameters on an "as available" basis. For the primary data sets, we developed a new method for filling the post-Pinatubo eruption data gap for 1991-1993 based on data from the Cryogenic Limb Array Etalon Spectrometer. In addition, we developed a new method for populating wintertime high latitudes during the SAGE period employing a latitude-equivalent latitude conversion process that greatly improves the depiction of aerosol at high latitudes compared to earlier similar efforts. We report data in the troposphere only when and where it is available. This is primarily during the SAGE II period except for the most enhanced part of the Pinatubo period. It is likely that the upper troposphere during Pinatubo was greatly enhanced over non-volcanic periods and that domain remains substantially under-characterized. We note that aerosol levels during the OSIRIS/CALIPSO period in the lower stratosphere at mid- and high latitudes is routinely higher than what we observed during the SAGE II period. While this period had nearly continuous low-level volcanic activity, it

  15. A global space-based stratospheric aerosol climatology: 1979–2016

    Directory of Open Access Journals (Sweden)

    L. W. Thomason

    2018-03-01

    Full Text Available We describe the construction of a continuous 38-year record of stratospheric aerosol optical properties. The Global Space-based Stratospheric Aerosol Climatology, or GloSSAC, provided the input data to the construction of the Climate Model Intercomparison Project stratospheric aerosol forcing data set (1979–2014 and we have extended it through 2016 following an identical process. GloSSAC focuses on the Stratospheric Aerosol and Gas Experiment (SAGE series of instruments through mid-2005, and on the Optical Spectrograph and InfraRed Imager System (OSIRIS and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO data thereafter. We also use data from other space instruments and from ground-based, air, and balloon borne instruments to fill in key gaps in the data set. The end result is a global and gap-free data set focused on aerosol extinction coefficient at 525 and 1020 nm and other parameters on an "as available" basis. For the primary data sets, we developed a new method for filling the post-Pinatubo eruption data gap for 1991–1993 based on data from the Cryogenic Limb Array Etalon Spectrometer. In addition, we developed a new method for populating wintertime high latitudes during the SAGE period employing a latitude-equivalent latitude conversion process that greatly improves the depiction of aerosol at high latitudes compared to earlier similar efforts. We report data in the troposphere only when and where it is available. This is primarily during the SAGE II period except for the most enhanced part of the Pinatubo period. It is likely that the upper troposphere during Pinatubo was greatly enhanced over non-volcanic periods and that domain remains substantially under-characterized. We note that aerosol levels during the OSIRIS/CALIPSO period in the lower stratosphere at mid- and high latitudes is routinely higher than what we observed during the SAGE II period. While this period had nearly continuous low

  16. Observations of Stratospheric Gravity Waves During the WB57F Aerosol Mission and Modeling with Mesoscale Model 5

    Science.gov (United States)

    Mahoney, M.; Hicke, J.; Rosenlof, K.; Tuck, A.; Hovde, S.

    2000-01-01

    On April 11, 1998 WB57F aircraft flew northwest at lower stratospheric altitudes from Houston, Texas, over eastern Wyoming as part of the WB57F Aerosol Mission to sample a vortex filament forecast to pass over that region.

  17. Stratospheric sulfate from the Gareloi eruption, 1980: Contribution to the ''ambient'' aerosol by a poorly documented volcanic eruption

    International Nuclear Information System (INIS)

    Sedlacek, W.A.; Mroz, E.J.; Heiken, G.

    1981-01-01

    While sampling stratospheric aerosols during July--August 1980 a plume of ''fresh'' volcanic debris was observed in the Northern hemisphere. The origin of this material seems to be a poorly documented explosive eruption of Gareloi valcano in the Aleutian Islands. The debris was sampled at an altitude of 19.2 km: almost twice the height of observed eruption clouds. Such remote, unobserved or poorly documented eruptions may be a source that helps maintain the ''ambient'' stratospheric aerosol background

  18. Toward a combined SAGE II-HALOE aerosol climatology: an evaluation of HALOE version 19 stratospheric aerosol extinction coefficient observations

    Directory of Open Access Journals (Sweden)

    L. W. Thomason

    2012-09-01

    Full Text Available Herein, the Halogen Occultation Experiment (HALOE aerosol extinction coefficient data is evaluated in the low aerosol loading period after 1996 as the first necessary step in a process that will eventually allow the production of a combined HALOE/SAGE II (Stratospheric Aerosol and Gas Experiment aerosol climatology of derived aerosol products including surface area density. Based on these analyses, it is demonstrated that HALOE's 3.46 μm is of good quality above 19 km and suitable for scientific applications above that altitude. However, it is increasingly suspect at lower altitudes and should not be used below 17 km under any circumstances after 1996. The 3.40 μm is biased by about 10% throughout the lower stratosphere due to the failure to clear NO2 but otherwise appears to be a high quality product down to 15 km. The 2.45 and 5.26 μm aerosol extinction coefficient measurements are clearly biased and should not be used for scientific applications after the most intense parts of the Pinatubo period. Many of the issues in the aerosol data appear to be related to either the failure to clear some interfering gas species or doing so poorly. For instance, it is clear that the 3.40 μm aerosol extinction coefficient measurements can be improved through the inclusion of an NO2 correction and could, in fact, end up as the highest quality overall HALOE aerosol extinction coefficient measurement. It also appears that the 2.45 and 5.26 μm channels may be improved by updating the Upper Atmosphere Pilot Database which is used as a resource for the removal of gas species otherwise not available from direct HALOE measurements. Finally, a simple model to demonstrate the promise of mixed visible/infrared aerosol extinction coefficient ensembles for the retrieval of bulk aerosol properties demonstrates that a combined HALOE/SAGE II aerosol climatology is feasible and may represent a substantial improvement over independently derived

  19. The Stratospheric Aerosol and Gas Experiment (SAGE III) on the International Space Station (ISS) Mission

    Science.gov (United States)

    Cisewski, Michael; Zawodny, Joseph; Gasbarre, Joseph; Eckman, Richard; Topiwala, Nandkishore; Rodriquez-Alvarez, Otilia; Cheek, Dianne; Hall, Steve

    2014-01-01

    The Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) mission will provide the science community with high-vertical resolution and nearly global observations of ozone, aerosols, water vapor, nitrogen dioxide, and other trace gas species in the stratosphere and upper-troposphere. SAGE III/ISS measurements will extend the long-term Stratospheric Aerosol Measurement (SAM) and SAGE data record begun in the 1970s. The multi-decadal SAGE ozone and aerosol data sets have undergone intense scrutiny and are considered the international standard for accuracy and stability. SAGE data have been used to monitor the effectiveness of the Montreal Protocol. Key objectives of the mission are to assess the state of the recovery in the distribution of ozone, to re-establish 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 space station mid-inclination orbit allows for a large range in latitude sampling and nearly continuous communications with payloads. The SAGE III instrument is the fifth in a series of instruments developed for monitoring atmospheric constituents with high vertical resolution. The SAGE III instrument is a moderate resolution spectrometer covering wavelengths from 290 nm to 1550 nm. Science data is collected in solar occultation mode, lunar occultation mode, and limb scatter measurement mode. A SpaceX Falcon 9 launch vehicle will provide access to space. Mounted in the unpressurized section of the Dragon trunk, SAGE III will be robotically removed from the Dragon and installed on the space station. SAGE III/ISS will be mounted to the ExPRESS Logistics Carrier-4 (ELC-4) location on the starboard side of the station. To facilitate a nadir view from this location, a Nadir Viewing Platform (NVP) payload was developed which mounts between the carrier and the SAGE III Instrument Payload (IP).

  20. Changing transport processes in the stratosphere by radiative heating of sulfate aerosols

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    U. Niemeier

    2017-12-01

    Full Text Available The injection of sulfur dioxide (SO2 into the stratosphere to form an artificial stratospheric aerosol layer is discussed as an option for solar radiation management. Sulfate aerosol scatters solar radiation and absorbs infrared radiation, which warms the stratospheric sulfur layer. Simulations with the general circulation model ECHAM5-HAM, including aerosol microphysics, show consequences of this warming, including changes of the quasi-biennial oscillation (QBO in the tropics. The QBO slows down after an injection of 4 Tg(S yr−1 and completely shuts down after an injection of 8 Tg(S yr−1. Transport of species in the tropics and sub-tropics depends on the phase of the QBO. Consequently, the heated aerosol layer not only impacts the oscillation of the QBO but also the meridional transport of the sulfate aerosols. The stronger the injection, the stronger the heating and the simulated impact on the QBO and equatorial wind systems. With increasing injection rate the velocity of the equatorial jet streams increases, and the less sulfate is transported out of the tropics. This reduces the global distribution of sulfate and decreases the radiative forcing efficiency of the aerosol layer by 10 to 14 % compared to simulations with low vertical resolution and without generated QBO. Increasing the height of the injection increases the radiative forcing only for injection rates below 10 Tg(S yr−1 (8–18 %, a much smaller value than the 50 % calculated previously. Stronger injection rates at higher levels even result in smaller forcing than the injections at lower levels.

  1. SAGE II observations of a previously unreported stratospheric volcanic aerosol cloud in the northern polar summer of 1990

    Science.gov (United States)

    Yue, Glenn K.; Veiga, Robert E.; Wang, Pi-Huan

    1994-01-01

    Analysis of aerosol extinction profiles obtained by the spaceborne SAGE II sensor reveals that there was an anomalous increase of aerosol extinction below 18.5 km at latitudes poleward of 50 deg N from July 28 to September 9, 1990. This widespread increase of aerosol extinction in the lower stratosphere was apparently due to a remote high-latitude volcanic eruption that has not been reported to date. The increase in stratospheric optical depth in the northern polar region was about 50% in August and had diminished by October 1990. This eruption caused an increase in stratospheric aerosol mass of about 0.33 x 10(exp 5) tons, assuming the aerosol was composed of sulfuric acid and water.

  2. First Simulations of Designing Stratospheric Sulfate Aerosol Geoengineering to Meet Multiple Simultaneous Climate Objectives: DESIGNING STRATOSPHERIC GEOENGINEERING

    Energy Technology Data Exchange (ETDEWEB)

    Kravitz, Ben [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland WA USA; MacMartin, Douglas G. [Mechanical and Aerospace Engineering, Cornell University, Ithaca NY USA; Department of Computing and Mathematical Sciences, California Institute of Technology, Pasadena CA USA; Mills, Michael J. [Atmospheric Chemistry, Observations, and Modeling Laboratory, National Center for Atmospheric Research, Boulder CO USA; Richter, Jadwiga H. [Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder CO USA; Tilmes, Simone [Atmospheric Chemistry, Observations, and Modeling Laboratory, National Center for Atmospheric Research, Boulder CO USA; Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder CO USA; Lamarque, Jean-Francois [Atmospheric Chemistry, Observations, and Modeling Laboratory, National Center for Atmospheric Research, Boulder CO USA; Tribbia, Joseph J. [Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder CO USA; Vitt, Francis [Atmospheric Chemistry, Observations, and Modeling Laboratory, National Center for Atmospheric Research, Boulder CO USA

    2017-12-07

    We describe the first simulations of stratospheric sulfate aerosol geoengineering using multiple injection locations to meet multiple simultaneous surface temperature objectives. Simulations were performed using CESM1(WACCM), a coupled atmosphere-ocean general circulation model with fully interactive stratospheric chemistry, dynamics (including an internally generated quasi-biennial oscillation), and a sophisticated treatment of sulfate aerosol formation, microphysical growth, and deposition. The objectives are defined as maintaining three temperature features at their 2020 levels against a background of the RCP8.5 scenario over the period 2020-2099. These objectives are met using a feedback mechanism in which the rate of sulfur dioxide injection at each of the four locations is adjusted independently every year of simulation. Even in the presence of uncertainties, nonlinearities, and variability, the objectives are met, predominantly by SO2 injection at 30°N and 30°S. By the last year of simulation, the feedback algorithm calls for a total injection rate of 51 Tg SO2 per year. The injections are not in the tropics, which results in a greater degree of linearity of the surface climate response with injection amount than has been found in many previous studies using injection at the equator. Because the objectives are defined in terms of annual mean temperature, the required geeongineering results in "overcooling" during summer and "undercooling" during winter. The hydrological cycle is also suppressed as compared to the reference values corresponding to the year 2020. The demonstration we describe in this study is an important step toward understanding what geoengineering can do and what it cannot do.

  3. Long-range transport of stratospheric aerosols in the Southern Hemisphere following the 2015 Calbuco eruption

    Directory of Open Access Journals (Sweden)

    N. Bègue

    2017-12-01

    Full Text Available After 43 years of inactivity, the Calbuco volcano, which is located in the southern part of Chile, erupted on 22 April 2015. The space–time evolutions (distribution and transport of its aerosol plume are investigated by combining satellite (CALIOP, IASI, OMPS, in situ aerosol counting (LOAC OPC and lidar observations, and the MIMOSA advection model. The Calbuco aerosol plume reached the Indian Ocean 1 week after the eruption. Over the Reunion Island site (21° S, 55.5° E, the aerosol signal was unambiguously enhanced in comparison with background conditions, with a volcanic aerosol layer extending from 18 to 21 km during the May–July period. All the data reveal an increase by a factor of  ∼  2 in the SAOD (stratospheric aerosol optical depth with respect to values observed before the eruption. The aerosol mass e-folding time is approximately 90 days, which is rather close to the value ( ∼  80 days reported for the Sarychev eruption. Microphysical measurements obtained before, during, and after the eruption reflecting the impact of the Calbuco eruption on the lower stratospheric aerosol content have been analyzed over the Reunion Island site. During the passage of the plume, the volcanic aerosol was characterized by an effective radius of 0.16 ± 0.02 µm with a unimodal size distribution for particles above 0.2 µm in diameter. Particle concentrations for sizes larger than 1 µm are too low to be properly detected by the LOAC OPC. The aerosol number concentration was  ∼  20 times higher that observed before and 1 year after the eruption. According to OMPS and lidar observations, a tendency toward conditions before the eruption was observed by April 2016. The volcanic aerosol plume is advected eastward in the Southern Hemisphere and its latitudinal extent is clearly bounded by the subtropical barrier and the polar vortex. The transient behavior of the aerosol layers observed above Reunion Island

  4. Ruby lidar observations and trajectory analysis of stratospheric aerosols injected by the volcanic eruptions of El Chichon

    Science.gov (United States)

    Uchino, O.; Tabata, T.; Akita, I.; Okada, Y.; Naito, K.

    1985-01-01

    Large amounts of aerosol particles and gases were injected into the lower stratosphere by the violet volcanic eruptions of El Chichon on March 28, and April 3 and 4, 1982. Observational results obtained by a ruby lidar at Tsukuba (36.1 deg N, 140.1 deg E) are shown, and some points of latitude dispersion processes of aerosols are discussed.

  5. 30-year lidar observations of the stratospheric aerosol layer state over Tomsk (Western Siberia, Russia)

    Science.gov (United States)

    Zuev, Vladimir V.; Burlakov, Vladimir D.; Nevzorov, Aleksei V.; Pravdin, Vladimir L.; Savelieva, Ekaterina S.; Gerasimov, Vladislav V.

    2017-02-01

    There are only four lidar stations in the world which have almost continuously performed observations of the stratospheric aerosol layer (SAL) state over the last 30 years. The longest time series of the SAL lidar measurements have been accumulated at the Mauna Loa Observatory (Hawaii) since 1973, the NASA Langley Research Center (Hampton, Virginia) since 1974, and Garmisch-Partenkirchen (Germany) since 1976. The fourth lidar station we present started to perform routine observations of the SAL parameters in Tomsk (56.48° N, 85.05° E, Western Siberia, Russia) in 1986. In this paper, we mainly focus on and discuss the stratospheric background period from 2000 to 2005 and the causes of the SAL perturbations over Tomsk in the 2006-2015 period. During the last decade, volcanic aerosol plumes from tropical Mt. Manam, Soufrière Hills, Rabaul, Merapi, Nabro, and Kelut and extratropical (northern) Mt. Okmok, Kasatochi, Redoubt, Sarychev Peak, Eyjafjallajökull, and Grímsvötn were detected in the stratosphere over Tomsk. When it was possible, we used the NOAA HYSPLIT trajectory model to assign aerosol layers observed over Tomsk to the corresponding volcanic eruptions. The trajectory analysis highlighted some surprising results. For example, in the cases of the Okmok, Kasatochi, and Eyjafjallajökull eruptions, the HYSPLIT air mass backward trajectories, started from altitudes of aerosol layers detected over Tomsk with a lidar, passed over these volcanoes on their eruption days at altitudes higher than the maximum plume altitudes given by the Smithsonian Institution Global Volcanism Program. An explanation of these facts is suggested. The role of both tropical and northern volcanic eruptions in volcanogenic aerosol loading of the midlatitude stratosphere is also discussed. In addition to volcanoes, we considered other possible causes of the SAL perturbations over Tomsk, i.e., the polar stratospheric cloud (PSC) events and smoke plumes from strong forest fires. At least

  6. Mt. St. Helens' aerosols: some tropospheric and stratospheric effects

    International Nuclear Information System (INIS)

    Michalsky, J.J.; Stokes, G.M.

    1983-01-01

    Aerosol optical depth measurements based on the attenuation of direct solar radiation before and after the six major explosive eruptions of Mt. St. Helens during 1980 are presented. These automated measurements are from a site 200 km mostly east and slightly north of the volcano. From the analysis it was concluded that in several cases the conversion of sulfur gases to sulfates proceeded much more rapidly (hours) than is usually found for tropospheric conditions. A possible explanation may be the greater availability of OH due to the presence of substantial water in the plume. The second major result of the analysis was that there was no evidence of a residual aerosol burden. Turbidity data taken between eruptions in 1980 were virtually identical in terms of magnitude and wavelength dependence to 1979 turbidity

  7. A risk-based framework for assessing the effectiveness of stratospheric aerosol geoengineering.

    Directory of Open Access Journals (Sweden)

    Angus J Ferraro

    Full Text Available Geoengineering by stratospheric aerosol injection has been proposed as a policy response to warming from human emissions of greenhouse gases, but it may produce unequal regional impacts. We present a simple, intuitive risk-based framework for classifying these impacts according to whether geoengineering increases or decreases the risk of substantial climate change, with further classification by the level of existing risk from climate change from increasing carbon dioxide concentrations. This framework is applied to two climate model simulations of geoengineering counterbalancing the surface warming produced by a quadrupling of carbon dioxide concentrations, with one using a layer of sulphate aerosol in the lower stratosphere, and the other a reduction in total solar irradiance. The solar dimming model simulation shows less regional inequality of impacts compared with the aerosol geoengineering simulation. In the solar dimming simulation, 10% of the Earth's surface area, containing 10% of its population and 11% of its gross domestic product, experiences greater risk of substantial precipitation changes under geoengineering than under enhanced carbon dioxide concentrations. In the aerosol geoengineering simulation the increased risk of substantial precipitation change is experienced by 42% of Earth's surface area, containing 36% of its population and 60% of its gross domestic product.

  8. A Risk-Based Framework for Assessing the Effectiveness of Stratospheric Aerosol Geoengineering

    Science.gov (United States)

    Ferraro, Angus J.; Charlton-Perez, Andrew J.; Highwood, Eleanor J.

    2014-01-01

    Geoengineering by stratospheric aerosol injection has been proposed as a policy response to warming from human emissions of greenhouse gases, but it may produce unequal regional impacts. We present a simple, intuitive risk-based framework for classifying these impacts according to whether geoengineering increases or decreases the risk of substantial climate change, with further classification by the level of existing risk from climate change from increasing carbon dioxide concentrations. This framework is applied to two climate model simulations of geoengineering counterbalancing the surface warming produced by a quadrupling of carbon dioxide concentrations, with one using a layer of sulphate aerosol in the lower stratosphere, and the other a reduction in total solar irradiance. The solar dimming model simulation shows less regional inequality of impacts compared with the aerosol geoengineering simulation. In the solar dimming simulation, 10% of the Earth's surface area, containing 10% of its population and 11% of its gross domestic product, experiences greater risk of substantial precipitation changes under geoengineering than under enhanced carbon dioxide concentrations. In the aerosol geoengineering simulation the increased risk of substantial precipitation change is experienced by 42% of Earth's surface area, containing 36% of its population and 60% of its gross domestic product. PMID:24533155

  9. A global, space-based stratospheric aerosol climatology: 1979 to 2014

    Science.gov (United States)

    Thomason, L. W.; Vernier, J. P.; Bourassa, A. E.; Millan, L.; Manney, G. L.

    2016-12-01

    Herein, we report on a global space-based stratospheric aerosol climatology (GloSSAC) that has been developed to support Coupled Model Intercomparison Project Phase 6 (CMIP6) (REF to CMIP6 and ETH work). GloSSAC is most closely related to the ASAP[SPARC, 2006] and CCMI data sets and follows a similar approach used to produce those data sets. It is primarily built using space-based measurements by a number of instruments including the SAGE series, OSIRIS, CALIPSO, CLAES and HALOE. The data set is presented as monthly depictions for 80S to 80N and from at least the tropopause to 40 km. The data set consists primarily of measurements by the instruments at their native wavelength and measurement type (e.g., extinction coefficient). However, every bin in these monthly grids receives measured or indirectly inferred values for aerosol extinction coefficient at 525 and 1020 nm. Generally, bins where no data are available are filled via simple linear interpolation in time only. The exceptions are in the SAGE I/II gap from 1982 to 1984 where data from SAM II and ground-based and airborne lidar data sets are used to span the 3 years between the end of the SAGE I mission in November 1981 and the beginning of the SAGE II mission in October 1984. Ground-based lidar also supplements space-based data in the months following the Pinatubo eruption when much of the lower stratosphere is too optically opaque for occultation measurements. This data set includes total aerosol surface area density and volume estimates based on Thomason et al.[2008] though these should be interpreted as bounding values (low and high) rather than functional aerosol parameters that are generally produced from this and predecessor data sets by other parties. Unlike previous versions of this data set, GloSSAC has been permanently archived at NASA's Atmospheric Science Data Center and a digital object identifier (doi) for GloSSAC is available. SPARC (2006), Assessment of Stratospheric Aerosol Properties (ASAP

  10. Chemistry and Microphysics of Lower Stratospheric Aerosols Determined by Satellite Remote Sensing

    Science.gov (United States)

    Zasetsky, A. Y.; Khalizov, A.; Sloan, J.

    2003-12-01

    Observations of broadband Infrared satellites such as ILAS-II (Ministry of the Environment, Japan, launched 14 December 2002) and SciSat-1 (Canadian Space Agency, launched 12 August 2003) can provide details of the chemical composition and particle size of atmospheric aerosols by direct inversion without recourse to models. During the past decade, we have developed mathematical methods to achieve this inversion by working with FTIR observations of model atmospheric aerosols in cryogenic flowtubes. More recently, we have converted these to operational algorithms for use in the above missions. In this presentation, we will briefly outline these procedures and illustrate their capabilities using laboratory data. These laboratory results show that the chemical compositions, phases and sizes of ensembles of particles can be obtained simultaneously using these procedures. We will also report chemical and microphysical properties of lower stratospheric clouds and aerosols derived by applying these procedures to observations from space.

  11. The Impact of Stratospheric Circulation Extremes on Minimum Arctic Sea Ice Extent

    Science.gov (United States)

    Smith, K. L.; Polvani, L. M.; Tremblay, B.

    2017-12-01

    The interannual variability of summertime Arctic sea ice extent (SIE) is anti-correlated with the leading mode of extratropical atmospheric variability in preceding winter, the Arctic Oscillation (AO). Given this relationship and the need for better seasonal predictions of Arctic SIE, we here examine the role of stratospheric circulation extremes and stratosphere-troposphere coupling in linking the AO and Arctic SIE variability. We show that extremes in the stratospheric circulation during the winter season, namely stratospheric sudden warming (SSW) and strong polar vortex (SPV) events, are associated with significant anomalies in sea ice concentration in the Bering Straight and the Sea of Okhotsk in winter, the Barents Sea in spring and along the Eurasian coastline in summer in both observations and a fully-coupled, stratosphere-resolving general circulation model. The accompanying figure shows the composite mean sea ice concentration anomalies from the Whole Atmosphere Community Climate Model (WACCM) for SSWs (N = 126, top row) and SPVs (N = 99, bottom row) for winter (a,d), spring (b,e) and summer (c,f). Consistent with previous work on the AO, we find that SSWs, which are followed by the negative phase of the AO at the surface, result in sea ice growth, whereas SPVs, which are followed by the positive phase of the AO at the surface, result in sea ice loss, although the dynamic and thermodynamic processes driving these sea ice anomalies in the three Arctic regions, noted above, are different. Our analysis suggests that the presence or absence of stratospheric circulation extremes in winter may play a non-trivial role in determining total September Arctic SIE when combined with other factors.

  12. Stratospheric Aerosol and Gas Experiments 1 and 2: Comparisons with ozonesondes

    Science.gov (United States)

    Veiga, Robert E.; Cunnold, Derek M.; Chu, William P.; McCormick, M. Patrick

    1995-01-01

    Ozone profiles measured by the Stratospheric Aerosol and Gas Experiments (SAGE) 1 and 2 are compared with ozonesonde profiles at 24 stations over the period extending from 1979 through 1991. Ozonesonde/satellite differences at 21 stations with SAGE 2 overpasses were computed down to 11.5 km in midlatitudes, to 15.5 km in the lower latitudes, and for nine stations with SAGE 1 overpasses down to 15.5 km. The set of individual satellite and ozonesonde profile comparisons most closely colocated in time and space shows mean absolute differences relative to the satellite measurement of 6 +/- 2% for SAGE 2 and 8 +/- 3% for SAGE 1. The ensemble of ozonesonde/satellite differences, when averaged over all altitudes, shows that for SAGE 2, 70% were less than 5%, whereas for SAGE 1, 50% were less than 5%. The best agreement occurred in the altitude region near the ozone density maximum where almost all the relative differences were less than 5%. Most of the statistically significant differences occurred below the ozone maximum down to the tropopause in the region of steepest ozone gradients and typically ranged between 0 and -20%. Correlations between ozone and aerosol extinction in the northern midlatitudes indicate that aerosols had no discernible impact on the ozonesonde/satellite differences and on the SAGE 2 ozone retrieval for the levels of extinction encountered in the lower stratosphere during 1984 to mid-1991.

  13. The ten-year pattern (1978-1987) of stratospheric aerosol loading using ground-based radiometry

    International Nuclear Information System (INIS)

    Michalsky, J.J.; Pearson, E.W.; LeBaron, B.A.

    1988-09-01

    In this paper the procedures used to obtain a stratospheric measurement with ground-based sun radiometry are reviewed briefly. The five-wavelength optical depths are then used to study the evolution of aerosol size during the decade. The time history of loading from the instruments described are compared. Particular emphasis will be placed on the Garmisch-Partenkirchen data because their latitude is very nearly that of the PNL site. The most useful data for this study are those observational records that measure total stratospheric aerosol burden and include the early period and continue throughout the eruption and decay of El Chichon. The lidar data from Langley Research Center and Fraunhofer-Institute for Atmospheric Environmental Research at Garmisch-Partenkirchen, the SAM II satellite data, and the Pacific Northwest Laboratory (PNL) sun radiometry are the published contiguous measurements of the stratosphere aerosol burden during this period. 16 refs., 6 figs

  14. On the recent measurements of the electric parameters and aerosols in the lower stratosphere

    International Nuclear Information System (INIS)

    Morita, Yasuhiro; Ishikawa, Haruji; Takagi, Masumi

    1979-01-01

    In Sanriku (Iwate), Laramie (Wyoming) and Hilo (Hawaii), ionization intensity, electric conductivity, atmospheric ion density and aerosol were observed by balloon flights simultaneously from October, 1973, to September, 1976. On the basis of these results, the influences of aerosol and geomagnetic latitude upon the electric conductivity and atmospheric ion density were examined. From the simultaneous observation of electric conductivity and ion density, the average electrical mobility of ions and also its vertical distribution were obtained. In the simultaneous observation of electric conductivity and aerosol at altitude below about 10 km, the effect of aerosol on ion annihilation was detectable. In the stratosphere above this level, the electric conductivity (or the atmospheric ion density) is determined only by the ionization intensity, and there was little effect of aerosol. This was also confirmed by the comparative observations in Japan and U.S. with different geomagnetic latitudes. The average vertical mobility of ions increased with altitude at Laramie and decreased at Hilo. (J.P.N.)

  15. Quantifying the temperature-independent effect of stratospheric aerosol geoengineering on global-mean precipitation in a multi-model ensemble

    International Nuclear Information System (INIS)

    Ferraro, Angus J; Griffiths, Hannah G

    2016-01-01

    The reduction in global-mean precipitation when stratospheric aerosol geoengineering is used to counterbalance global warming from increasing carbon dioxide (CO 2 ) concentrations has been mainly attributed to the temperature-independent effect of CO 2 on atmospheric radiative cooling. We demonstrate here that stratospheric sulphate aerosol itself also acts to reduce global-mean precipitation independent of its effects on temperature. The temperature-independent effect of stratospheric aerosol geoenginering on global-mean precipitation is calculated by removing temperature-dependent effects from climate model simulations of the Geoengineering Model Intercomparison Project (GeoMIP). When sulphate aerosol is injected into the stratosphere at a rate of 5 Tg SO 2 per year the aerosol reduces global-mean precipitation by approximately 0.2 %, though multiple ensemble members are required to separate this effect from internal variability. For comparison, the precipitation reduction from the temperature-independent effect of increasing CO 2 concentrations under the RCP4.5 scenario of the future is approximately 0.5 %. The temperature-independent effect of stratospheric sulphate aerosol arises from the aerosol’s effect on tropospheric radiative cooling. Radiative transfer calculations show this is mainly due to increasing downward emission of infrared radiation by the aerosol, but there is also a contribution from the stratospheric warming the aerosol causes. Our results suggest climate model simulations of solar dimming can capture the main features of the global-mean precipitation response to stratospheric aerosol geoengineering. (letter)

  16. The impact of volcanic aerosol on the Northern Hemisphere stratospheric polar vortex: mechanisms and sensitivity to forcing structure

    Science.gov (United States)

    Toohey, M.; Krüger, K.; Bittner, M.; Timmreck, C.; Schmidt, H.

    2014-12-01

    Observations and simple theoretical arguments suggest that the Northern Hemisphere (NH) stratospheric polar vortex is stronger in winters following major volcanic eruptions. However, recent studies show that climate models forced by prescribed volcanic aerosol fields fail to reproduce this effect. We investigate the impact of volcanic aerosol forcing on stratospheric dynamics, including the strength of the NH polar vortex, in ensemble simulations with the Max Planck Institute Earth System Model. The model is forced by four different prescribed forcing sets representing the radiative properties of stratospheric aerosol following the 1991 eruption of Mt. Pinatubo: two forcing sets are based on observations, and are commonly used in climate model simulations, and two forcing sets are constructed based on coupled aerosol-climate model simulations. For all forcings, we find that simulated temperature and zonal wind anomalies in the NH high latitudes are not directly impacted by anomalous volcanic aerosol heating. Instead, high-latitude effects result from enhancements in stratospheric residual circulation, which in turn result, at least in part, from enhanced stratospheric wave activity. High-latitude effects are therefore much less robust than would be expected if they were the direct result of aerosol heating. Both observation-based forcing sets result in insignificant changes in vortex strength. For the model-based forcing sets, the vortex response is found to be sensitive to the structure of the forcing, with one forcing set leading to significant strengthening of the polar vortex in rough agreement with observation-based expectations. Differences in the dynamical response to the forcing sets imply that reproducing the polar vortex responses to past eruptions, or predicting the response to future eruptions, depends on accurate representation of the space-time structure of the volcanic aerosol forcing.

  17. The role of carbonyl sulphide as a source of stratospheric sulphate aerosol and its impact on climate

    Directory of Open Access Journals (Sweden)

    C. Brühl

    2012-02-01

    Full Text Available Globally, carbonyl sulphide (COS is the most abundant sulphur gas in the atmosphere. Our chemistry-climate model (CCM of the lower and middle atmosphere with aerosol module realistically simulates the background stratospheric sulphur cycle, as observed by satellites in volcanically quiescent periods. The model results indicate that upward transport of COS from the troposphere largely controls the sulphur budget and the aerosol loading of the background stratosphere. This differs from most previous studies which indicated that short-lived sulphur gases are also important. The model realistically simulates the modulation of the particulate and gaseous sulphur abundance in the stratosphere by the quasi-biennial oscillation (QBO. In the lowermost stratosphere organic carbon aerosol contributes significantly to extinction. Further, using a chemical radiative convective model and recent spectra, we compute that the direct radiative forcing efficiency by 1 kg of COS is 724 times that of 1 kg CO2. Considering an anthropogenic fraction of 30% (derived from ice core data, this translates into an overall direct radiative forcing by COS of 0.003 W m−2. The direct global warming potentials of COS over time horizons of 20 and 100 yr are GWP(20 yr = 97 and GWP(100 yr = 27, respectively (by mass. Furthermore, stratospheric aerosol particles produced by the photolysis of COS (chemical feedback contribute to a negative direct solar radiative forcing, which in the CCM amounts to −0.007 W m−2 at the top of the atmosphere for the anthropogenic fraction, more than two times the direct warming forcing of COS. Considering that the lifetime of COS is twice that of stratospheric aerosols the warming and cooling tendencies approximately cancel.

  18. Comparing Simultaneous Stratospheric Aerosol and Ozone Lidar Measurements with SAGE 2 Data after the Mount Pinatubo Eruption

    Science.gov (United States)

    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.

  19. Preliminary assessment of possible aerosol contamination effects on SAGE ozone trends in the lower stratosphere

    Science.gov (United States)

    Cunnold, Derek M.; Veiga, Robert E.

    1991-01-01

    An investigation of the validity of long-term ozone trends in the lower stratosphere derived from SAGE I and II measurements is described. At altitudes below approximately 20 km, it is important to separate the ozone and aerosol contributions to SAGE extinction at 600 nm. The correlation between SAGE II measurements of ozone and aerosols indicates that most of the variability in these parameters is associated with physically induced variations resulting from quasi-horizontal motions of air parcels. The SAGE ozone measurements are however found to be as much as 20 percent larger than coincident ozonesonde measurements between 15 and 20 km altitude. A sudden change in the difference at approximately 14.5 km altitude for which there is a change in the SAGE aerosol retrieval procedure suggests that SAGE ozone trends below 20 km altitude may be more sensitive to aerosol variations. Between 20 and 25 km altitude, however, both SAGE and the ozonesondes indicate a reduction in ozone of approximately 0.5 percent/year over the period 1979 to 1989 at midlatitudes of the Northern Hemisphere.

  20. Comparison of the impact of volcanic eruptions and aircraft emissions on the aerosol mass loading and sulfur budget in the stratosphere

    Science.gov (United States)

    Yue, Glenn K.; Poole, Lamont R.

    1992-01-01

    Data obtained by the Stratospheric Aerosol and Gas Experiment (SAGE) 1 and 2 were used to study the temporal variation of aerosol optical properties and to assess the mass loading of stratospheric aerosols from the eruption of volcanos Ruiz and Kelut. It was found that the yearly global average of optical depth at 1.0 micron for stratospheric background aerosols in 1979 was 1.16 x 10(exp -3) and in 1989 was 1.66 x 10(exp -3). The eruptions of volcanos Ruiz and Kelut ejected at least 5.6 x 10(exp 5) and 1.8 x 10(exp 5) tons of materials into the stratosphere, respectively. The amount of sulfur emitted per year from the projected subsonic and supersonic fleet is comparable to that contained in the background aerosol particles in midlatitudes from 35 deg N to 55 deg N.

  1. The Climate Response to Stratospheric Aerosol Geoengineering Can Be Tailored Using Multiple Injection Locations

    Energy Technology Data Exchange (ETDEWEB)

    MacMartin, Douglas G. [Mechanical and Aerospace Engineering, Cornell University, Ithaca NY USA; Department of Computing and Mathematical Sciences, California Institute of Technology, Pasadena CA USA; Kravitz, Ben [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland WA USA; Tilmes, Simone [Atmospheric Chemistry, Observations, and Modeling Laboratory, National Center for Atmospheric Research, Boulder CO USA; Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder CO USA; Richter, Jadwiga H. [Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder CO USA; Mills, Michael J. [Atmospheric Chemistry, Observations, and Modeling Laboratory, National Center for Atmospheric Research, Boulder CO USA; Lamarque, Jean-Francois [Atmospheric Chemistry, Observations, and Modeling Laboratory, National Center for Atmospheric Research, Boulder CO USA; Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder CO USA; Tribbia, Joseph J. [Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder CO USA; Vitt, Francis [Atmospheric Chemistry, Observations, and Modeling Laboratory, National Center for Atmospheric Research, Boulder CO USA

    2017-12-07

    The climate response to geoengineering with stratospheric aerosols has the potential to be designed to achieve some chosen objectives. By injecting different amounts of SO2 at multiple different latitudes, the spatial pattern of aerosol optical depth (AOD) can be partially controlled. We use simulations from the fully-coupled whole-atmosphere chemistry-climate model CESM1(WACCM), to demonstrate that three spatial degrees of freedom of AOD can be achieved by appropriately combining injection at different locations: an approximately spatially-uniform AOD distribution, the relative difference in AOD between Northern and Southern hemispheres, and the relative AOD in high versus low latitudes. For forcing levels that yield 1–2°C cooling, the AOD and surface temperature response are sufficiently linear in this model so that many climate effects can be predicted from single-latitude injection simulations. Optimized injection at multiple locations is predicted to improve compensation of CO2-forced climate change, relative to a case using only equatorial aerosol injection. The additional degrees of freedom can be used, for example, to balance interhemispheric temperature differences and the equator to pole temperature difference in addition to the global mean temperature; this is projected in this model to reduce the mean-square error in temperature compensation by 30%.

  2. Relevant climate response tests for stratospheric aerosol injection: A combined ethical and scientific analysis

    Science.gov (United States)

    Lenferna, Georges Alexandre; Russotto, Rick D.; Tan, Amanda; Gardiner, Stephen M.; Ackerman, Thomas P.

    2017-06-01

    In this paper, we focus on stratospheric sulfate injection as a geoengineering scheme, and provide a combined scientific and ethical analysis of climate response tests, which are a subset of outdoor tests that would seek to impose detectable and attributable changes to climate variables on global or regional scales. We assess the current state of scientific understanding on the plausibility and scalability of climate response tests. Then, we delineate a minimal baseline against which to consider whether certain climate response tests would be relevant for a deployment scenario. Our analysis shows that some climate response tests, such as those attempting to detect changes in regional climate impacts, may not be deployable in time periods relevant to realistic geoengineering scenarios. This might pose significant challenges for justifying stratospheric sulfate aerosol injection deployment overall. We then survey some of the major ethical challenges that proposed climate response tests face. We consider what levels of confidence would be required to ethically justify approving a proposed test; whether the consequences of tests are subject to similar questions of justice, compensation, and informed consent as full-scale deployment; and whether questions of intent and hubris are morally relevant for climate response tests. We suggest further research into laboratory-based work and modeling may help to narrow the scientific uncertainties related to climate response tests, and help inform future ethical debate. However, even if such work is pursued, the ethical issues raised by proposed climate response tests are significant and manifold.

  3. First Simulations of Designing Stratospheric Sulfate Aerosol Geoengineering to Meet Multiple Simultaneous Climate Objectives

    Science.gov (United States)

    Kravitz, Ben; MacMartin, Douglas G.; Mills, Michael J.; Richter, Jadwiga H.; Tilmes, Simone; Lamarque, Jean-Francois; Tribbia, Joseph J.; Vitt, Francis

    2017-12-01

    We describe the first simulations of stratospheric sulfate aerosol geoengineering using multiple injection locations to meet multiple simultaneous surface temperature objectives. Simulations were performed using CESM1(WACCM), a coupled atmosphere-ocean general circulation model with fully interactive stratospheric chemistry, dynamics (including an internally generated quasi-biennial oscillation), and a sophisticated treatment of sulfate aerosol formation, microphysical growth, and deposition. The objectives are defined as maintaining three temperature features at their 2020 levels against a background of the RCP8.5 scenario over the period 2020-2099. These objectives are met using a feedback mechanism in which the rate of sulfur dioxide injection at each of the four locations is adjusted independently every year of simulation. Even in the presence of uncertainties, nonlinearities, and variability, the objectives are met, predominantly by SO2 injection at 30°N and 30°S. By the last year of simulation, the feedback algorithm calls for a total injection rate of 51 Tg SO2 per year. The injections are not in the tropics, which results in a greater degree of linearity of the surface climate response with injection amount than has been found in many previous studies using injection at the equator. Because the objectives are defined in terms of annual mean temperature, the required geongineering results in "overcooling" during summer and "undercooling" during winter. The hydrological cycle is also suppressed as compared to the reference values corresponding to the year 2020. The demonstration we describe in this study is an important step toward understanding what geoengineering can do and what it cannot do.

  4. A simple method to compute the change in earth-atmosphere radiative balance due to a stratospheric aerosol layer

    Science.gov (United States)

    Lenoble, J.; Tanre, D.; Deschamps, P. Y.; Herman, M.

    1982-01-01

    A computer code was developed in terms of a three-layer model for the earth-atmosphere system, using a two-stream approximation for the troposphere and stratosphere. The analysis was limited to variable atmosphere loading by solar radiation over an unperturbed section of the atmosphere. The scattering atmosphere above a Lambertian ground layer was considered in order to derive the planar albedo and the spherical albedo. Attention was given to the influence of the aerosol optical thickness in the stratosphere, the single scattering albedo and asymmetry factor, and the sublayer albedo. Calculations were performed of the zonal albedo and the planetary radiation balance, taking into account a stratospheric aerosol layer containing H2SO4 droplets and volcanic ash. The resulting ground temperature disturbance was computed using a Budyko (1969) climate model. Local decreases in the albedo in the summer were observed in high latitudes, implying a heating effect of the aerosol. An accompanying energy loss of 23-27 W/sq m was projected, which translates to surface temperature decreases of either 1.1 and 0.45 C, respectively, for background and volcanic aerosols.

  5. Modeling of Solar Radiation Management: A Comparison of Simulations Using Reduced Solar Constant and Stratospheric Sulphate Aerosols

    Science.gov (United States)

    Bala, G.; Kalidindi, S.; Modak, A.; Caldeira, K.

    2014-12-01

    Several climate modelling studies in the past have used reduction in solar constant to simulate the climatic effects of Solar Radiation Management (SRM) geoengineering. This is most likely valid only for space-based mirrors/reflectors but not for SRM methods that rely on stratospheric aerosols. In this study, we use a climate model to evaluate the differences in climate response to SRM by uniform solar constant reduction and stratospheric aerosols. The experiments are designed such that global mean warming from a doubling of atmospheric CO2 concentration (2xCO2) is nearly cancelled in each case. In such a scenario, the residual climate effects are similar when important surface and tropospheric climate variables such as temperature and precipitation are considered. However, there are significant differences in stratospheric temperature response and diffuse and direct radiation reaching the surface. A difference of 1K in the global mean stratospheric (61-9.8 hPa) temperature is simulated between the two SRM methods, with warming in the aerosol scheme and a slight cooling for sunshades. While the global mean surface diffuse radiation increases by ~23% and direct radiation decreases by about 9% in the case of aerosol SRM method, both direct and diffuse radiation decrease by similar fractional amounts (~1.0%) when solar constant is reduced. When CO2 fertilization effects from elevated CO2 concentration levels are removed, the contribution from shaded leaves to gross primary productivity (GPP) increases by 1.8 % in aerosol SRM because of increased diffuse light. However, this increase is almost offset by a 15.2% decline in sunlit contribution due to reduced direct light. Overall both the SRM simulations show similar decrease in GPP (~ 8%) and NPP (~3%) relative to 2xCO2, indicating the negligible effect of the fractional changes in direct/diffuse radiation on the overall plant productivity. Based on our modelling study, we conclude that the climate states produced by a

  6. Observed perturbations of the Earth's Radiation Budget - A response to the El Chichon stratospheric aerosol layer?

    Science.gov (United States)

    Ardanuy, P. E.; Kyle, H. L.

    1986-01-01

    The Earth Radiation Budget experiment, launched aboard the Nimbus-7 polar-orbiting spacecraft in late 1978, has now taken over seven years of measurements. The dataset, which is global in coverage, consists of the individual components of the earth's radiation budget, including longwave emission, net radiation, and both total and near-infrared albedos. Starting some six months after the 1982 eruption of the El Chichon volcano, substantial long-lived positive shortwave irradiance anomalies were observed by the experiment in both the northern and southern polar regions. Analysis of the morphology of this phenomena indicates that the cause is the global stratospheric aerosol layer which formed from the cloud of volcanic effluents. There was little change in the emitted longwave in the polar regions. At the north pole the largest anomaly was in the near-infrared, but at the south pole the near UV-visible anomaly was larger. Assuming an exponential decay, the time constant for the north polar, near-infrared anomaly was 1.2 years. At mid- and low latitudes the effect of the El Chichon aerosol layer could not be separated from the strong reflected-shortwave and emitted-longwave perturbations issuing from the El Nino/Southern Oscillation event of 1982-83.

  7. On recent (2008–2012 stratospheric aerosols observed by lidar over Japan

    Directory of Open Access Journals (Sweden)

    O. Uchino

    2012-12-01

    Full Text Available An increase in stratospheric aerosols caused by the volcanic eruption of Mt. Nabro (13.37° N, 41.70° E on 12 June 2011 was detected by lidar at Tsukuba (36.05° N, 140.13° E and Saga (33.24° N, 130.29° E in Japan. The maximum backscattering ratios at a wavelength of 532 nm were 2.0 at 17.0 km on 10 July 2011 at Tsukuba and 3.6 at 18.2 km on 23 June 2011 at Saga. The maximum integrated backscattering coefficients (IBCs at 532 nm above the first tropopause height were 4.18×10−4 sr−1 on 11 February 2012 at Tsukuba and 4.19×10−4 sr−1 on 23 June 2011 at Saga, respectively.

    A time series of lidar observational results at Tsukuba have also been reported from January 2008 through May 2012. Increases in stratospheric aerosols were observed after the volcanic eruptions of Mt. Kasatochi (52.18° N, 175.51° E in August 2008 and Mt. Sarychev Peak (48.09° N, 153.20° E in June 2009. The yearly averaged IBCs at Tsukuba were 2.54×10−4 sr−1, 2.48×10−4 sr−1, 2.45×10−4 sr−1, and 2.20×10−4 sr−1 for 2008, 2009, 2010, and 2011, respectively. These values were about twice the IBC background level (1.21×10−4 sr−1 from 1997 to 2001 at Tsukuba. We briefly discuss the influence of the increased aerosols on climate and the implications for analysis of satellite data.

  8. Stratospheric Aerosol and Gas Experiment II measurements of the quasi-biennial oscillations in ozone and nitrogen dioxide

    Science.gov (United States)

    Zawodny, Joseph M.; Mccormick, M. P.

    1991-01-01

    The first measurements ever to show a quasi-biennial oscillation (QBO) in NO2 have been made by the Stratospheric Aerosol and Gas Experiment II) (SAGE II) and are presented in this work along with observations of the well-known QBO in stratospheric ozone. The SAGE II instrument was launched aboard the Earth Radiation Budget satellite near the end of 1984. Measurements of ozone and nitrogen dioxide through early 1990 are analyzed for the presence of a quasi-biennial oscillation. The measurements show the global extent of both the O3 and NO2 QBO in the 25- to 40-km region of the stratosphere. The SAGE II QBO results for ozone compare favorably to theory and previous measurements. The QBO in NO2 is found to be consistent with the vertical and horizontal transport of NOy. Both species exhibit a QBO at extratropical latitudes consistent with strong meridional transport into the winter hemisphere.

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

    Science.gov (United States)

    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.

  10. SPICE Work Package 3: Modelling the Effects of Stratospheric Aerosol Geoengineering

    Science.gov (United States)

    Driscoll, Simon

    2015-04-01

    This talk presents the results of the SPICE Work Package 3. There is an obvious need for methods to verify the accuracy of geoengineering given no observations of a geoengineering programme. Accordingly, model ability in reproducing the observed dynamical response to volcanic eruptions is discussed using analysis of CMIP5 data and different configurations of the HadGEM2 model. With the HadGEM2-L60 model shown to be substantially better in reproducing the observed dynamical response to volcanic eruptions, simulations of GeoMIP's G4 scenario are performed. Simulated impacts of geoengineering are described, and asymmetries between the immediate onset and immediate cessation ('termination') of geoengineering are analysed. Whilst a rapid large increase in stratospheric sulphate aerosols (such as from volcanic eruptions) can cause substantial damage, most volcanic eruptions in general are not catastrophic. One may therefore suspect that an 'equal but opposite' change in radiative forcing from termination may therefore not be catastrophic, if the climatic response is simulated to be symmetric. HadGEM2 simulations reveal a substantially more rapid change in variables such as near-surface temperature and precipitation following termination than the onset, indicating that termination may be substantially more damaging and even catastrophic. Some suggestions for hemispherically asymmetric geoengineering have been proposed as a way to reduce Northern Hemisphere sea ice, for example, with lesser impacts on the rest of the climate. However, HadGEM2 simulations are performed and observations analysed following volcanic eruptions. Both indicate substantial averse consequences from hemispherically asymmetric loading of stratospheric loading on precipitation in the Sahelian region - a vulnerable region where drought has caused hundreds of thousands of deaths and created millions of refugees in the past.

  11. Sources of increase in lowermost stratospheric sulphurous and carbonaceous aerosol background concentrations during 1999–2008 derived from CARIBIC flights

    Directory of Open Access Journals (Sweden)

    Johan Friberg

    2014-03-01

    Full Text Available This study focuses on sulphurous and carbonaceous aerosol, the major constituents of particulate matter in the lowermost stratosphere (LMS, based on in situ measurements from 1999 to 2008. Aerosol particles in the size range of 0.08–2 µm were collected monthly during intercontinental flights with the CARIBIC passenger aircraft, presenting the first long-term study on carbonaceous aerosol in the LMS. Elemental concentrations were derived via subsequent laboratory-based ion beam analysis. The stoichiometry indicates that the sulphurous fraction is sulphate, while an O/C ratio of 0.2 indicates that the carbonaceous aerosol is organic. The concentration of the carbonaceous component corresponded on average to approximately 25% of that of the sulphurous, and could not be explained by forest fires or biomass burning, since the average mass ratio of Fe to K was 16 times higher than typical ratios in effluents from biomass burning. The data reveal increasing concentrations of particulate sulphur and carbon with a doubling of particulate sulphur from 1999 to 2008 in the northern hemisphere LMS. Periods of elevated concentrations of particulate sulphur in the LMS are linked to downward transport of aerosol from higher altitudes, using ozone as a tracer for stratospheric air. Tropical volcanic eruptions penetrating the tropical tropopause are identified as the likely cause of the particulate sulphur and carbon increase in the LMS, where entrainment of lower tropospheric air into volcanic jets and plumes could be the cause of the carbon increase.

  12. Diagnosing causes of extreme aerosol optical depth events

    Science.gov (United States)

    Bernstein, D. N.; Sullivan, R.; Crippa, P.; Thota, A.; Pryor, S. C.

    2017-12-01

    Aerosol burdens and optical properties exhibit substantial spatiotemporal variability, and simulation of current and possible future aerosol burdens and characteristics exhibits relatively high uncertainty due to uncertainties in emission estimates and in chemical and physical processes associated with aerosol formation, dynamics and removal. We report research designed to improve understanding of the causes and characteristics of extreme aerosol optical depth (AOD) at the regional scale, and diagnose and attribute model skill in simulating these events. Extreme AOD events over the US Midwest are selected by identifying all dates on which AOD in a MERRA-2 reanalysis grid cell exceeds the local seasonally computed 90th percentile (p90) value during 2004-2016 and then finding the dates on which the highest number of grid cells exceed their local p90. MODIS AOD data are subsequently used to exclude events dominated by wildfires. MERRA-2 data are also analyzed within a synoptic classification to determine in what ways the extreme AOD events are atypical and to identify possible meteorological `finger-prints' that can be detected in regional climate model simulations of future climate states to project possible changes in the occurrence of extreme AOD. Then WRF-Chem v3.6 is applied at 12-km resolution and regridded to the MERRA-2 resolution over eastern North America to quantify model performance, and also evaluated using in situ measurements of columnar AOD (AERONET) and near-surface PM2.5 (US EPA). Finally the sensitivity to (i) spin-up time (including procedure used to spin-up the chemistry), (ii) modal versus sectional aerosol schemes, (iii) meteorological nudging, (iv) chemistry initial and boundary conditions, and (v) anthropogenic emissions is quantified. Despite recent declines in mean AOD, supraregional (> 1000 km) extreme AOD events continue to occur. During these events AOD exceeds 0.6 in many Midwestern grid cells for multiple consecutive days. In all

  13. Glacier evolution in high-mountain Asia under stratospheric sulfate aerosol injection geoengineering

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    L. Zhao

    2017-06-01

    Full Text Available Geoengineering by stratospheric sulfate aerosol injection may help preserve mountain glaciers by reducing summer temperatures. We examine this hypothesis for the glaciers in high-mountain Asia using a glacier mass balance model driven by climate simulations from the Geoengineering Model Intercomparison Project (GeoMIP. The G3 and G4 schemes specify use of stratospheric sulfate aerosols to reduce the radiative forcing under the Representative Concentration Pathway (RCP 4.5 scenario for the 50 years between 2020 and 2069, and for a further 20 years after termination of geoengineering. We estimate and compare glacier volume loss for every glacier in the region using a glacier model based on surface mass balance parameterization under climate projections from three Earth system models under G3, five models under G4, and six models under RCP4.5 and RCP8.5. The ensemble projections suggest that glacier shrinkage over the period 2010–2069 is equivalent to sea-level rise of 9.0 ± 1.6 mm (G3, 9.8 ± 4.3 mm (G4, 15.5 ± 2.3 mm (RCP4.5, and 18.5 ± 1.7 mm (RCP8.5. Although G3 keeps the average temperature from increasing in the geoengineering period, G3 only slows glacier shrinkage by about 50 % relative to losses from RCP8.5. Approximately 72 % of glaciated area remains at 2069 under G3, as compared with about 30 % for RCP8.5. The widely reported reduction in mean precipitation expected for solar geoengineering is unlikely to be as important as the temperature-driven shift from solid to liquid precipitation for forcing Himalayan glacier change. The termination of geoengineering at 2069 under G3 leads to temperature rise of about 1.3 °C over the period 2070–2089 relative to the period 2050-2069 and corresponding increase in annual mean glacier volume loss rate from 0.17 to 1.1 % yr−1, which is higher than the 0.66 % yr−1 under RCP8.5 during 2070–2089.

  14. Observation of an unusual mid-stratospheric aerosol layer in the Arctic: possible sources and implications for polar vortex dynamics

    Directory of Open Access Journals (Sweden)

    M. Gerding

    Full Text Available By the beginning of winter 2000/2001, a mysterious stratospheric aerosol layer had been detected by four different Arctic lidar stations. The aerosol layer was observed first on 16 November 2000, at an altitude of about 38 km near Søndre Strømfjord, Greenland (67° N, 51° W and on 19 November 2000, near Andenes, Norway (69°  N, 16°  E. Subsequently, in early December 2000, the aerosol layer was observed near Kiruna, Sweden (68°  N, 21°  E and Ny-Ålesund, Spitsbergen (79°  N, 12°  E. No mid-latitude lidar station observed the presence of aerosols in this altitude region. The layer persisted throughout the winter 2000/2001, at least up to 12 February 2001. In November 2000, the backscatter ratio at a wavelength of 532 nm was up to 1.1, with a FWHM of about 2.5 km. By early February 2001, the layer had sedimented from an altitude of 38 km to about 26 km. Measurements at several wavelengths by the ALOMAR and Koldewey lidars indicate the particle size was between 30 and 50 nm. Depolarisation measurements reveal that the particles in the layer are aspherical, hence solid. In the mid-stratosphere, the ambient atmospheric temperature was too high to support in situ formation or existence of cloud particles consisting of ice or an acid-water solution. Furthermore, in the year 2000 there was no volcanic eruption, which could have injected aerosols into the upper stratosphere. Therefore, other origins of the aerosol, such as meteoroid debris, condensed rocket fuel, or aerosols produced under the influence of charged solar particles, will be discussed in the paper. Trajectory calculations illustrate the path of the aerosol cloud within the polar vortex and are used to link the observations at the different lidar sites. From the descent rate of  the layer and particle sedimentation rates, the mean down-ward motion of air within the polar vortex was estimated to be about 124 m/d between 35 and 30 km, with higher values at the edge of the

  15. Observation of an unusual mid-stratospheric aerosol layer in the Arctic: possible sources and implications for polar vortex dynamics

    Directory of Open Access Journals (Sweden)

    M. Gerding

    2003-04-01

    Full Text Available By the beginning of winter 2000/2001, a mysterious stratospheric aerosol layer had been detected by four different Arctic lidar stations. The aerosol layer was observed first on 16 November 2000, at an altitude of about 38 km near Søndre Strømfjord, Greenland (67° N, 51° W and on 19 November 2000, near Andenes, Norway (69°  N, 16°  E. Subsequently, in early December 2000, the aerosol layer was observed near Kiruna, Sweden (68°  N, 21°  E and Ny-Ålesund, Spitsbergen (79°  N, 12°  E. No mid-latitude lidar station observed the presence of aerosols in this altitude region. The layer persisted throughout the winter 2000/2001, at least up to 12 February 2001. In November 2000, the backscatter ratio at a wavelength of 532 nm was up to 1.1, with a FWHM of about 2.5 km. By early February 2001, the layer had sedimented from an altitude of 38 km to about 26 km. Measurements at several wavelengths by the ALOMAR and Koldewey lidars indicate the particle size was between 30 and 50 nm. Depolarisation measurements reveal that the particles in the layer are aspherical, hence solid. In the mid-stratosphere, the ambient atmospheric temperature was too high to support in situ formation or existence of cloud particles consisting of ice or an acid-water solution. Furthermore, in the year 2000 there was no volcanic eruption, which could have injected aerosols into the upper stratosphere. Therefore, other origins of the aerosol, such as meteoroid debris, condensed rocket fuel, or aerosols produced under the influence of charged solar particles, will be discussed in the paper. Trajectory calculations illustrate the path of the aerosol cloud within the polar vortex and are used to link the observations at the different lidar sites. From the descent rate of  the layer and particle sedimentation rates, the mean down-ward motion of air within the polar vortex was estimated to be about 124 m/d between 35 and 30 km, with higher values at the edge of the

  16. Impact of Idealized Stratospheric Aerosol Injection on the Future Ocean and Land Carbon Cycles

    Science.gov (United States)

    Tjiputra, J.; Lauvset, S.

    2017-12-01

    Using a state-of-the-art Earth system model, we simulate stratospheric aerosol injection (SAI) on top of the Representative Concentration Pathways 8.5 future scenario. Our idealized method prescribes aerosol concentration, linearly increasing from 2020 to 2100, and thereafter remaining constant until 2200. In one of the scenarios, the model able to project future warming below 2 degree toward 2100, despite greatier warming persists in the high latitudes. When SAI is terminated in 2100, a rapid global warming of 0.35 K yr-1 (as compared to 0.05 K yr-1 under RCP8.5) is simulated in the subsequent 10 years, and the global mean temperature rapidly returns to levels close to the reference state. In contrast to earlier findings, we show a weak response in the terrestrial carbon sink during SAI implementation in the 21st century, which we attribute to nitrogen limitation. The SAI increases the land carbon uptake in the temperate forest-, grassland-, and shrub-dominated regions. The resultant lower temperatures lead to a reduction in the heterotrophic respiration rate and increase soil carbon retention. Changes in precipitation patterns are key drivers for variability in vegetation carbon. Upon SAI termination, the level of vegetation carbon storage returns to the reference case, whereas the soil carbon remains high. The ocean absorbs nearly 10% more carbon in the geoengineered simulation than in the reference simulation, leading to a ˜15 ppm lower atmospheric CO2 concentration in 2100. The largest enhancement in uptake occurs in the North Atlantic. In both hemispheres' polar regions, SAI delays the sea ice melting and, consequently, export production remains low. Despite inducing little impact on surface acidification, in the deep water of North Atlantic, SAI-induced circulation changes accelerate the ocean acidification rate and broaden the affected area. Since the deep ocean provides vital ecosystem function and services, e.g., fish stocks, this accelerated changes

  17. The Influence of Stratospheric Sulphate Aerosol Deployment on the Surface Air Temperature and the Risk of an Abrupt Global Warming

    Directory of Open Access Journals (Sweden)

    Roland von Glasow

    2010-12-01

    Full Text Available We used the ‘Radiative-Convective Model of the Earth-atmosphere system’ (OGIM to investigate the cooling effects induced by sulphur injections into the stratosphere. The ensemble of numerical calculations was based on the A1B scenario from the IPCC Special Report on Emissions Scenarios (SRES. Several geoengineered scenarios were analysed, including the abrupt interruption of these injections in different scenarios and at different dates. We focused on the surface air temperature (SAT anomalies induced by stratospheric sulphate aerosol generated in order to compensate future warming. Results show that continuous deployment of sulphur into the stratosphere could induce a lasting decrease in SAT. Retaining a constant aerosol loading equivalent to 6 TgS would delay the expected global warming by 53 years. Keeping the SAT constant in a context of increasing greenhouse gases (GHGs means that the aerosol loading needs to be increased by 1.9% annually. This would offset the effect of increasing GHG under the A1B scenario. A major focus of this study was on the heating rates of SAT that would arise in different scenarios in case of an abrupt cessation of sulphur injections into the stratosphere. Our model results show that heating rates after geoengineering interruption would be 15–28 times higher than in a case without geoengineering, with likely important consequences for life on Earth. Larger initial sulphate loadings induced more intense warming rates when the geoengineering was stopped at the same time. This implies that, if sulphate loading was increased to maintain constant SAT in the light of increasing GHG concentrations, the later the geoengineering interruption was to occur, the higher the heating rates would be. Consequently, geoengineering techniques like this should only be regarded as last-resort measures and require intense further research should they ever become necessary.

  18. Effects on stratospheric moistening by rates of change of aerosol optical depth and ozone due to solar activity in extra-tropics

    Science.gov (United States)

    Saha, U.; Maitra, A.

    2014-11-01

    The solar-induced changes in ozone and aerosol optical depth have relative effects on stratospheric moistening at upper troposphere/lower stratosphere region. Wavelet-based multi-scale principal component analysis technique has been applied to de-noise component of quasi-biennial oscillation and El Niño-Southern Oscillation from ozone and aerosol optical depth variations. Rate of change of aerosol optical depth sharply increases indicating a positive gradient whereas rate of change of ozone sharply decreases indicating a negative gradient with solar activity during the years 2004-2010. It is also observed that with increase of rate of change of aerosol optical depth, there is a sharp increase of stratospheric moistening caused by enhanced deep convection. On the contrary, with the increase of stratospheric moistening, there is a sharp decrease of rate of change of ozone resulting in a cross-over between the two parameters. An increase in aerosol optical depth may cause a significant increase in the gradient of vertical temperature profile, as well as formation of cloud condensation nuclei, clouds and hence rainfall. This may lead to formation of strong convective system in the atmosphere that is essential for vertical transfer of water vapour in the tropics percolating tropical tropopause layer and depleting stratospheric ozone in the extra-tropics.

  19. Atmospheric Sampling of Aerosols to Stratospheric Altitudes using High Altitude Balloons

    Science.gov (United States)

    Jerde, E. A.; Thomas, E.

    2010-12-01

    Although carbon dioxide represents a long-lived atmospheric component relevant to global climate change, it is also understood that many additional contributors influence the overall climate of Earth. Among these, short-lived components are more difficult to incorporate into models due to uncertainties in the abundances of these both spatially and temporally. Possibly the most significant of these short-lived components falls under the heading of “black carbon” (BC). There are numerous overlapping definitions of BC, but it is basically carbonaceous in nature and light absorbing. Due to its potential as a climate forcer, an understanding of the BC population in the atmosphere is critical for modeling of radiative forcing. Prior measurements of atmospheric BC generally consist of airplane- and ground-based sampling, typically below 5000 m and restricted in time and space. Given that BC has a residence time on the order of days, short-term variability is easily missed. Further, since the radiative forcing is a result of BC distributed through the entire atmospheric column, aircraft sampling is by definition incomplete. We are in the process of planning a more comprehensive sampling of the atmosphere for BC using high-altitude balloons. Balloon-borne sampling is a highly reliable means to sample air through the entire troposphere and into the lower stratosphere. Our system will incorporate a balloon and a flight train of two modules. One module will house an atmospheric sampler. This sampler will be single-stage (samples all particle sizes together), and will place particles directly on an SEM sample stub for analysis. The nozzle depositing the sample will be offset from the center of the stub, placing the aerosol particles toward the edge. At various altitudes, the stub will be rotated 45 degrees, providing 6-8 sample “cuts” of particle populations through the atmospheric column. The flights will reach approximately 27 km altitude, above which the balloons

  20. Lifting options for stratospheric aerosol geoengineering: advantages of tethered balloon systems.

    Science.gov (United States)

    Davidson, Peter; Burgoyne, Chris; Hunt, Hugh; Causier, Matt

    2012-09-13

    The Royal Society report 'Geoengineering the Climate' identified solar radiation management using albedo-enhancing aerosols injected into the stratosphere as the most affordable and effective option for geoengineering, but did not consider in any detail the options for delivery. This paper provides outline engineering analyses of the options, both for batch-delivery processes, following up on previous work for artillery shells, missiles, aircraft and free-flying balloons, as well as a more lengthy analysis of continuous-delivery systems that require a pipe connected to the ground and supported at a height of 20 km, either by a tower or by a tethered balloon. Towers are shown not to be practical, but a tethered balloon delivery system, with high-pressure pumping, appears to have much lower operating and capital costs than all other delivery options. Instead of transporting sulphuric acid mist precursors, such a system could also be used to transport slurries of high refractive index particles such as coated titanium dioxide. The use of such particles would allow useful experiments on opacity, coagulation and atmospheric chemistry at modest rates so as not to perturb regional or global climatic conditions, thus reducing scale-up risks. Criteria for particle choice are discussed, including the need to minimize or prevent ozone destruction. The paper estimates the time scales and relatively modest costs required if a tethered balloon system were to be introduced in a measured way with testing and development work proceeding over three decades, rather than in an emergency. The manufacture of a tether capable of sustaining the high tensions and internal pressures needed, as well as strong winds, is a significant challenge, as is the development of the necessary pumping and dispersion technologies. The greatest challenge may be the manufacture and launch of very large balloons, but means have been identified to significantly reduce the size of such balloons or aerostats.

  1. Sulfate Aerosols from Non-Explosive Volcanoes: Chemical-Radiative Effects in the Troposphere and Lower Stratosphere

    Directory of Open Access Journals (Sweden)

    Giovanni Pitari

    2016-06-01

    Full Text Available SO2 and H2S are the two most important gas-phase sulfur species emitted by volcanoes, with a global amount from non-explosive emissions of the order 10 Tg-S/yr. These gases are readily oxidized forming SO42− aerosols, which effectively scatter the incoming solar radiation and cool the surface. They also perturb atmospheric chemistry by enhancing the NOx to HNO3 heterogeneous conversion via hydrolysis on the aerosol surface of N2O5 and Br-Cl nitrates. This reduces formation of tropospheric O3 and the OH to HO2 ratio, thus limiting the oxidation of CH4 and increasing its lifetime. In addition to this tropospheric chemistry perturbation, there is also an impact on the NOx heterogeneous chemistry in the lower stratosphere, due to vertical transport of volcanic SO2 up to the tropical tropopause layer. Furthermore, the stratospheric O3 formation and loss, as well as the NOx budget, may be slightly affected by the additional amount of upward diffused solar radiation and consequent increase of photolysis rates. Two multi-decadal time-slice runs of a climate-chemistry-aerosol model have been designed for studying these chemical-radiative effects. A tropopause mean global net radiative flux change (RF of −0.23 W·m−2 is calculated (including direct and indirect aerosol effects with a 14% increase of the global mean sulfate aerosol optical depth. A 5–15 ppt NOx decrease is found in the mid-troposphere subtropics and mid-latitudes and also from pole to pole in the lower stratosphere. The tropospheric NOx perturbation triggers a column O3 decrease of 0.5–1.5 DU and a 1.1% increase of the CH4 lifetime. The surface cooling induced by solar radiation scattering by the volcanic aerosols induces a tropospheric stabilization with reduced updraft velocities that produce ice supersaturation conditions in the upper troposphere. A global mean 0.9% decrease of the cirrus ice optical depth is calculated with an indirect RF of −0.08 W·m−2.

  2. Optimal estimation retrieval of aerosol microphysical properties from SAGE II satellite observations in the volcanically unperturbed lower stratosphere

    Directory of Open Access Journals (Sweden)

    T. Deshler

    2010-05-01

    Full Text Available Stratospheric aerosol particles under non-volcanic conditions are typically smaller than 0.1 μm. Due to fundamental limitations of the scattering theory in the Rayleigh limit, these tiny particles are hard to measure by satellite instruments. As a consequence, current estimates of global aerosol properties retrieved from spectral aerosol extinction measurements tend to be strongly biased. Aerosol surface area densities, for instance, are observed to be about 40% smaller than those derived from correlative in situ measurements (Deshler et al., 2003. An accurate knowledge of the global distribution of aerosol properties is, however, essential to better understand and quantify the role they play in atmospheric chemistry, dynamics, radiation and climate. To address this need a new retrieval algorithm was developed, which employs a nonlinear Optimal Estimation (OE method to iteratively solve for the monomodal size distribution parameters which are statistically most consistent with both the satellite-measured multi-wavelength aerosol extinction data and a priori information. By thus combining spectral extinction measurements (at visible to near infrared wavelengths with prior knowledge of aerosol properties at background level, even the smallest particles are taken into account which are practically invisible to optical remote sensing instruments. The performance of the OE retrieval algorithm was assessed based on synthetic spectral extinction data generated from both monomodal and small-mode-dominant bimodal sulphuric acid aerosol size distributions. For monomodal background aerosol, the new algorithm was shown to fairly accurately retrieve the particle sizes and associated integrated properties (surface area and volume densities, even in the presence of large extinction uncertainty. The associated retrieved uncertainties are a good estimate of the true errors. In the case of bimodal background aerosol, where the retrieved (monomodal size

  3. Optimal estimation retrieval of aerosol microphysical properties from SAGE~II satellite observations in the volcanically unperturbed lower stratosphere

    Science.gov (United States)

    Wurl, D.; Grainger, R. G.; McDonald, A. J.; Deshler, T.

    2010-05-01

    Stratospheric aerosol particles under non-volcanic conditions are typically smaller than 0.1 μm. Due to fundamental limitations of the scattering theory in the Rayleigh limit, these tiny particles are hard to measure by satellite instruments. As a consequence, current estimates of global aerosol properties retrieved from spectral aerosol extinction measurements tend to be strongly biased. Aerosol surface area densities, for instance, are observed to be about 40% smaller than those derived from correlative in situ measurements (Deshler et al., 2003). An accurate knowledge of the global distribution of aerosol properties is, however, essential to better understand and quantify the role they play in atmospheric chemistry, dynamics, radiation and climate. To address this need a new retrieval algorithm was developed, which employs a nonlinear Optimal Estimation (OE) method to iteratively solve for the monomodal size distribution parameters which are statistically most consistent with both the satellite-measured multi-wavelength aerosol extinction data and a priori information. By thus combining spectral extinction measurements (at visible to near infrared wavelengths) with prior knowledge of aerosol properties at background level, even the smallest particles are taken into account which are practically invisible to optical remote sensing instruments. The performance of the OE retrieval algorithm was assessed based on synthetic spectral extinction data generated from both monomodal and small-mode-dominant bimodal sulphuric acid aerosol size distributions. For monomodal background aerosol, the new algorithm was shown to fairly accurately retrieve the particle sizes and associated integrated properties (surface area and volume densities), even in the presence of large extinction uncertainty. The associated retrieved uncertainties are a good estimate of the true errors. In the case of bimodal background aerosol, where the retrieved (monomodal) size distributions naturally

  4. Earth Science With the Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station

    Science.gov (United States)

    Zawodny, Joe; Vernier, Jean-Paul; Thomason, Larry; Roell, Marilee; Pitts, Mike; Moore, Randy; Hill, Charles; Flittner, David; Damadeo, Rob; Cisewski, Mike

    2015-01-01

    The Stratospheric Aerosol and Gas Experiment (SAGE) III is the fourth generation of solar occultation instruments operated by NASA, the first coming under a different acronym, to investigate the Earth's upper atmosphere. Three flight-ready SAGE III instruments were built by Ball Aerospace in the late 1990s, with one launched aboard the former Russian Aviation and Space Agency (now known as Roskosmos) Meteor-3M platform on 10 December 2001 (continuing until the platform lost power in 2006). Another of the original instruments was manifested for the ISS in the 2004 time frame, but was delayed because of budgetary considerations. Fortunately, that SAGE III/ISS mission was restarted in 2009 with a major focus upon filling an anticipated gap in ozone and aerosol observation in the second half of this decade. Here we discuss the mission architecture, its implementation, and data that will be produced by SAGE III/ISS, including their expected accuracy and coverage. The 52-degree inclined orbit of the ISS is well-suited for solar occultation and provides near-global observations on a monthly basis with excellent coverage of low and mid-latitudes. This is similar to that of the SAGE II mission (1985-2005), whose data set has served the international atmospheric science community as a standard for stratospheric ozone and aerosol measurements. The nominal science products include vertical profiles of trace gases, such as ozone, nitrogen dioxide and water vapor, along with multi-wavelength aerosol extinction. Though in the visible portion of the spectrum the brightness of the Sun is one million times that of the full Moon, the SAGE III instrument is designed to cover this large dynamic range and also perform lunar occultations on a routine basis to augment the solar products. The standard lunar products were demonstrated during the SAGE III/M3M mission and include ozone, nitrogen dioxide & nitrogen trioxide. The operational flexibility of the SAGE III spectrometer accomplishes

  5. Sulfur deposition changes under sulfate geoengineering conditions: quasi-biennial oscillation effects on the transport and lifetime of stratospheric aerosols

    Science.gov (United States)

    Visioni, Daniele; Pitari, Giovanni; Tuccella, Paolo; Curci, Gabriele

    2018-02-01

    Sustained injection of sulfur dioxide (SO2) in the tropical lower stratosphere has been proposed as a climate engineering technique for the coming decades. Among several possible environmental side effects, the increase in sulfur deposition deserves additional investigation. In this study we present results from a composition-climate coupled model (University of L'Aquila Composition-Chemistry Model, ULAQ-CCM) and a chemistry-transport model (Goddard Earth Observing System Chemistry-Transport Model, GEOS-Chem), assuming a sustained lower-stratospheric equatorial injection of 8 Tg SO2 yr-1. Total S deposition is found to globally increase by 5.2 % when sulfate geoengineering is deployed, with a clear interhemispheric asymmetry (+3.8 and +10.3 % in the Northern Hemisphere (NH) and the Southern Hemisphere (SH), due to +2.2 and +1.8 Tg S yr-1, respectively). The two models show good consistency, both globally and on a regional scale under background and geoengineering conditions, except for S-deposition changes over Africa and the Arctic. The consistency exists with regard to time-averaged values but also with regard to monthly and interannual deposition changes. The latter is driven essentially by the variability in stratospheric large-scale transport associated with the quasi-biennial oscillation (QBO). Using an externally nudged QBO, it is shown how a zonal wind E shear favors aerosol confinement in the tropical pipe and a significant increase in their effective radius (+13 % with respect to W shear conditions). The net result is an increase in the downward cross-tropopause S flux over the tropics with dominant E shear conditions with respect to W shear periods (+0.61 Tg S yr-1, +42 %, mostly due to enhanced aerosol gravitational settling) and a decrease over the extratropics (-0.86 Tg S yr-1, -35 %, mostly due to decreased large-scale stratosphere-troposphere exchange of geoengineering sulfate). This translates into S-deposition changes that are significantly

  6. Investigations of the Background Stratospheric Aerosol Using Multicolor Wide-Angle Measurements of the Twilight Glow Background

    Science.gov (United States)

    Ugolnikov, O. S.; Maslov, I. A.

    2018-03-01

    The first results of multiwave measurements of twilight background and the all-sky camera with a color (RGB) CCD matrix conducted in the spring and summer of 2016 in Central Russia (55.2° N, 37.5° E) have been discussed. The observations reveal the effect of aerosol scattering at heights of up to 35 km, which is substantially enhanced in the long-wave part of the spectrum (R band with an effective wavelength of 624 nm). An analysis of the behavior of the sky color during light period of twilight with allowance for the absorption by ozone in the Chappuis bands make it possible to restore the angular dependences of the intensity of the aerosol scattering of the light. This is used to determine the parameters of the lognormal distribution of aerosol particles over their sizes with a mean radius of 0.08 μm and a width of 1.5-1.6 for the stratospheric height interval.

  7. Effect of volcanic aerosol on stratospheric NO2 and N2O5 from 2002–2014 as measured by Odin-OSIRIS and Envisat-MIPAS

    Directory of Open Access Journals (Sweden)

    C. Adams

    2017-07-01

    Full Text Available Following the large volcanic eruptions of Pinatubo in 1991 and El Chichón in 1982, decreases in stratospheric NO2 associated with enhanced aerosol were observed. The Optical Spectrograph and Infrared Imaging Spectrometer (OSIRIS measured the widespread enhancements of stratospheric aerosol following seven volcanic eruptions between 2002 and 2014, although the magnitudes of these eruptions were all much smaller than the Pinatubo and El Chichón eruptions. In order to isolate and quantify the relationship between volcanic aerosol and NO2, NO2 anomalies were calculated using measurements from OSIRIS and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS. In the tropics, variability due to the quasi-biennial oscillation was subtracted from the time series. OSIRIS profile measurements indicate that the strongest anticorrelations between NO2 and volcanic aerosol extinction were for the 5 km layer starting  ∼  3 km above the climatological mean tropopause at the given latitude. OSIRIS stratospheric NO2 partial columns in this layer were found to be smaller than background NO2 levels during these aerosol enhancements by up to  ∼  60 % with typical Pearson correlation coefficients of R ∼ −0. 7. MIPAS also observed decreases in NO2 partial columns during periods affected by volcanic aerosol, with percent differences of up to  ∼  25 % relative to background levels. An even stronger anticorrelation was observed between OSIRIS aerosol optical depth and MIPAS N2O5 partial columns, with R ∼ −0. 9, although no link with MIPAS HNO3 was observed. The variation in OSIRIS NO2 with increasing aerosol was found to be consistent with simulations from a photochemical box model within the estimated model uncertainty.

  8. Quantifying enhancement in aerosol radiative forcing during 'extreme aerosol days' in summer at Delhi National Capital Region, India.

    Science.gov (United States)

    Kumar, Sumant; Dey, Sagnik; Srivastava, Arun

    2016-04-15

    Changes in aerosol characteristics (spectral aerosol optical depth, AOD and composition) are examined during the transition from 'relatively clean' to 'extreme' aerosol days in the summer of 2012 at Delhi National Capital Region (NCR), India. AOD smaller than 0.54 (i.e. 12-year mean AOD-1σ) represents 'relatively clean' days in Delhi during the summer. 'Extreme' days are defined by the condition when AOD0.5 exceeds 12-year mean AOD+1 standard deviation (σ). Mean (±1σ) AOD increases to 1.2±0.12 along with a decrease of Angstrom Exponent from 0.54±0.09 to 0.22±0.12 during the 'extreme' days. Aerosol composition is inferred by fixing the number concentrations of various individual species through iterative tweaking when simulated (following Mie theory) AOD spectrum matches with the measured one. Contribution of coarse mode dust to aerosol mass increased from 76.8% (relatively clean) to 96.8% (extreme events), while the corresponding contributions to AOD0.5 increased from 35.0% to 70.8%. Spectrally increasing single scattering albedo (SSA) and CALIPSO aerosol sub-type information support the dominant presence of dust during the 'extreme' aerosol days. Aerosol direct radiative forcing (ADRF) at the top-of-the-atmosphere increases from 21.2Wm(-2) (relatively clean) to 56.6Wm(-2) (extreme), while the corresponding change in surface ADRF is from -99.5Wm(-2) to -153.5Wm(-2). Coarse mode dust contributes 60.3% of the observed surface ADRF during the 'extreme' days. On the contrary, 0.4% mass fraction of black carbon (BC) translates into 13.1% contribution to AOD0.5 and 33.5% to surface ADRF during the 'extreme' days. The atmospheric heating rate increased by 75.1% from 1.7K/day to 2.96K/day during the 'extreme' days. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Total Volcanic Stratospheric Aerosol Optical Depths and Implications for Global Climate Change

    Science.gov (United States)

    Ridley, D. A.; Solomon, S.; Barnes, J. E.; Burlakov, V. D.; Deshler, T.; Dolgii, S. I.; Herber, A. B.; Nagai, T.; Neely, R. R., III; Nevzorov, A. V.; hide

    2014-01-01

    Understanding the cooling effect of recent volcanoes is of particular interest in the context of the post-2000 slowing of the rate of global warming. Satellite observations of aerosol optical depth above 15 km have demonstrated that small-magnitude volcanic eruptions substantially perturb incoming solar radiation. Here we use lidar, Aerosol Robotic Network, and balloon-borne observations to provide evidence that currently available satellite databases neglect substantial amounts of volcanic aerosol between the tropopause and 15 km at middle to high latitudes and therefore underestimate total radiative forcing resulting from the recent eruptions. Incorporating these estimates into a simple climate model, we determine the global volcanic aerosol forcing since 2000 to be 0.19 +/- 0.09W/sq m. This translates into an estimated global cooling of 0.05 to 0.12 C. We conclude that recent volcanic events are responsible for more post-2000 cooling than is implied by satellite databases that neglect volcanic aerosol effects below 15 km.

  10. Stratospheric Aerosol and Gas Experiment, SAGE III on ISS, An Earth Science Mission on the International Space Station, Schedule Risk Analysis, A Project Perspective

    Science.gov (United States)

    Bonine, Lauren

    2015-01-01

    The presentation provides insight into the schedule risk analysis process used by the Stratospheric Aerosol and Gas Experiment III on the International Space Station Project. The presentation focuses on the schedule risk analysis process highlighting the methods for identification of risk inputs, the inclusion of generic risks identified outside the traditional continuous risk management process, and the development of tailored analysis products used to improve risk informed decision making.

  11. Impact of idealized future stratospheric aerosol injection on the large-scale ocean and land carbon cycles

    Science.gov (United States)

    Tjiputra, J. F.; Grini, A.; Lee, H.

    2016-01-01

    Using an Earth system model, we simulate stratospheric aerosol injection (SAI) on top of the Representative Concentration Pathways 8.5 future scenario. Our idealized method prescribes aerosol concentration, linearly increasing from 2020 to 2100, and thereafter remaining constant until 2200. In the aggressive scenario, the model projects a cooling trend toward 2100 despite warming that persists in the high latitudes. Following SAI termination in 2100, a rapid global warming of 0.35 K yr-1 is simulated in the subsequent 10 years, and the global mean temperature returns to levels close to the reference state, though roughly 0.5 K cooler. In contrast to earlier findings, we show a weak response in the terrestrial carbon sink during SAI implementation in the 21st century, which we attribute to nitrogen limitation. The SAI increases the land carbon uptake in the temperate forest-, grassland-, and shrub-dominated regions. The resultant lower temperatures lead to a reduction in the heterotrophic respiration rate and increase soil carbon retention. Changes in precipitation patterns are key drivers for variability in vegetation carbon. Upon SAI termination, the level of vegetation carbon storage returns to the reference case, whereas the soil carbon remains high. The ocean absorbs nearly 10% more carbon in the geoengineered simulation than in the reference simulation, leading to a ˜15 ppm lower atmospheric CO2 concentration in 2100. The largest enhancement in uptake occurs in the North Atlantic. In both hemispheres' polar regions, SAI delays the sea ice melting and, consequently, export production remains low. In the deep water of North Atlantic, SAI-induced circulation changes accelerate the ocean acidification rate and broaden the affected area.

  12. Quantifying enhancement in aerosol radiative forcing during ‘extreme aerosol days’ in summer at Delhi National Capital Region, India

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sumant [School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Dey, Sagnik [Centre for Atmospheric Sciences, IIT Delhi, New Delhi 110016 (India); Srivastava, Arun [School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067 (India)

    2016-04-15

    Changes in aerosol characteristics (spectral aerosol optical depth, AOD and composition) are examined during the transition from ‘relatively clean’ to ‘extreme’ aerosol days in the summer of 2012 at Delhi National Capital Region (NCR), India. AOD smaller than 0.54 (i.e. 12-year mean AOD − 1σ) represents ‘relatively clean’ days in Delhi during the summer. ‘Extreme’ days are defined by the condition when AOD{sub 0.5} exceeds 12-year mean AOD + 1 standard deviation (σ). Mean (± 1σ) AOD increases to 1.2 ± 0.12 along with a decrease of Angstrom Exponent from 0.54 ± 0.09 to 0.22 ± 0.12 during the ‘extreme’ days. Aerosol composition is inferred by fixing the number concentrations of various individual species through iterative tweaking when simulated (following Mie theory) AOD spectrum matches with the measured one. Contribution of coarse mode dust to aerosol mass increased from 76.8% (relatively clean) to 96.8% (extreme events), while the corresponding contributions to AOD{sub 0.5} increased from 35.0% to 70.8%. Spectrally increasing single scattering albedo (SSA) and CALIPSO aerosol sub-type information support the dominant presence of dust during the ‘extreme’ aerosol days. Aerosol direct radiative forcing (ADRF) at the top-of-the-atmosphere increases from 21.2 W m{sup −2} (relatively clean) to 56.6 W m{sup −2} (extreme), while the corresponding change in surface ADRF is from − 99.5 W m{sup −2} to − 153.5 W m{sup −2}. Coarse mode dust contributes 60.3% of the observed surface ADRF during the ‘extreme’ days. On the contrary, 0.4% mass fraction of black carbon (BC) translates into 13.1% contribution to AOD{sub 0.5} and 33.5% to surface ADRF during the ‘extreme’ days. The atmospheric heating rate increased by 75.1% from 1.7 K/day to 2.96 K/day during the ‘extreme’ days. - Graphical abstract: Deviation (in %) of aerosol properties from ‘relatively clean’ days to ‘extreme’ aerosol days. - Highlights:

  13. Does Extreme El Niño Have a Different Effect on the Stratosphere in Boreal Winter Than Its Moderate Counterpart?

    Science.gov (United States)

    Zhou, Xin; Li, Jianping; Xie, Fei; Chen, Quanliang; Ding, Ruiqiang; Zhang, Wenxia; Li, Yang

    2018-03-01

    A robust impact of El Niño on the Northern Hemisphere (NH) polar stratosphere has been demonstrated by previous studies, although whether this applies to extreme El Niño is uncertain. The time evolution of the response of the NH stratospheric vortex to extreme El Niño, compared with that to moderate eastern Pacific El Niño, is addressed by means of composite analysis using the National Centers for Environmental Prediction/Department of Energy reanalysis data set from 1980 to 2016. Lead-lag analysis indicates that the El Niño signal actually leads the stratospheric response by 2 months. Considering the time lag, the signal of December-January-February El Niño in the NH stratospheric vortex should mature in the February-March-April season (late winter/early spring). The patterns of circulation and temperature for late winter/early spring during extreme and moderate El Niño events are significant, exhibiting similar structure. The results are confirmed with the Whole Atmosphere Community Climate Model version 4 model, which is forced with observed SSTs of extreme and moderate El Niño in winter (December-January-February) to analyze the day-to-day propagation of their signals. Note that the magnitudes of the stratospheric responses are much larger in the case of extreme El Niño, as stronger upward propagation of planetary waves leads to a weaker northern polar vortex than during moderate El Niño events.

  14. A Chronology of Annual-Mean Effective Radii of Stratospheric Aerosols from Volcanic Eruptions During the Twentieth Century as Derived From Ground-based Spectral Extinction Measurements

    Science.gov (United States)

    Strothers, Richard B.; Hansen, James E. (Technical Monitor)

    2001-01-01

    Stratospheric extinction can be derived from ground-based spectral photometric observations of the Sun and other stars (as well as from satellite and aircraft measurements, available since 1979), and is found to increase after large volcanic eruptions. This increased extinction shows a characteristic wavelength dependence that gives information about the chemical composition and the effective (or area weighted mean) radius of the particles responsible for it. Known to be tiny aerosols constituted of sulfuric acid in a water solution, the stratospheric particles at midlatitudes exhibit a remarkable uniformity of their column-averaged effective radii r(sub eff) in the first few months after the eruption. Considering the seven largest eruptions of the twentieth century, r(sub eff) at this phase of peak aerosol abundance is approx. 0.3 micrometers in all cases. A year later, r(sub eff) either has remained about the same size (almost certainly in the case of the Katmai eruption of 1912) or has increased to approx. 0.5 micrometers (definitely so for the Pinatubo eruption of 1991). The reasons for this divergence in aerosol growth are unknown.

  15. Condensed Acids In Antartic Stratospheric Clouds

    Science.gov (United States)

    Pueschel, R. F.; Snetsinger, K. G.; Toon, O. B.; Ferry, G. V.; Starr, W. L.; Oberbeck, V. R.; Chan, K. R.; Goodman, J. K.; Livingston, J. M.; Verma, S.; hide

    1992-01-01

    Report dicusses nitrate, sulfate, and chloride contents of stratospheric aerosols during 1987 Airborne Antarctic Ozone Experiment. Emphasizes growth of HNO3*3H2O particles in polar stratospheric clouds. Important in testing theories concerning Antarctic "ozone hole".

  16. Aerosol particle size distribution in the stratosphere retrieved from SCIAMACHY limb measurements

    Directory of Open Access Journals (Sweden)

    E. Malinina

    2018-04-01

    Full Text Available w can be retrieved with an uncertainty of less than 20 %. The algorithm was successfully applied to the tropical region (20° N–20° S for 10 years (2002–2012 of SCIAMACHY observations in limb-viewing geometry, establishing a unique data set. Analysis of this new climatology for the particle size distribution parameters showed clear increases in the mode radius after the tropical volcanic eruptions, whereas no distinct behaviour of the absolute distribution width could be identified. A tape recorder, which describes the time lag as the perturbation propagates to higher altitudes, was identified for both parameters after the volcanic eruptions. A quasi-biannual oscillation (QBO pattern at upper altitudes (28–32 km is prominent in the anomalies of the analysed parameters. A comparison of the aerosol effective radii derived from SCIAMACHY and SAGE II data was performed. The average difference is found to be around 30 % at the lower altitudes, decreasing with increasing height to almost zero around 30 km. The data sample available for the comparison is, however, relatively small.

  17. Impacts of Anthropogenic Aerosols on Regional Climate: Extreme Events, Stagnation, and the United States Warming Hole

    Science.gov (United States)

    Mascioli, Nora R.

    Extreme temperatures, heat waves, heavy rainfall events, drought, and extreme air pollution events have adverse effects on human health, infrastructure, agriculture and economies. The frequency, magnitude and duration of these events are expected to change in the future in response to increasing greenhouse gases and decreasing aerosols, but future climate projections are uncertain. A significant portion of this uncertainty arises from uncertainty in the effects of aerosol forcing: to what extent were the effects from greenhouse gases masked by aerosol forcing over the historical observational period, and how much will decreases in aerosol forcing influence regional and global climate over the remainder of the 21st century? The observed frequency and intensity of extreme heat and precipitation events have increased in the U.S. over the latter half of the 20th century. Using aerosol only (AER) and greenhouse gas only (GHG) simulations from 1860 to 2005 in the GFDL CM3 chemistry-climate model, I parse apart the competing influences of aerosols and greenhouse gases on these extreme events. I find that small changes in extremes in the "all forcing" simulations reflect cancellations between the effects of increasing anthropogenic aerosols and greenhouse gases. In AER, extreme high temperatures and the number of days with temperatures above the 90th percentile decline over most of the U.S., while in GHG high temperature extremes increase over most of the U.S. The spatial response patterns in AER and GHG are significantly anti-correlated, suggesting a preferred regional mode of response that is largely independent of the type of forcing. Extreme precipitation over the eastern U.S. decreases in AER, particularly in winter, and increases over the eastern and central U.S. in GHG, particularly in spring. Over the 21 st century under the RCP8.5 emissions scenario, the patterns of extreme temperature and precipitation change associated with greenhouse gas forcing dominate. The

  18. Potential impact of carbonaceous aerosol on the upper troposphere and lower stratosphere (UTLS) and precipitation during Asian summer monsoon in a global model simulation

    KAUST Repository

    Fadnavis, Suvarna

    2017-09-28

    Recent satellite observations show efficient vertical transport of Asian pollutants from the surface to the upper-level anticyclone by deep monsoon convection. In this paper, we examine the transport of carbonaceous aerosols, including black carbon (BC) and organic carbon (OC), into the monsoon anticyclone using of ECHAM6-HAM, a global aerosol climate model. Further, we investigate impacts of enhanced (doubled) carbonaceous aerosol emissions on the upper troposphere and lower stratosphere (UTLS), underneath monsoon circulation and precipitation from sensitivity simulations. The model simulation shows that boundary layer aerosols are transported into the monsoon anticyclone by the strong monsoon convection from the Bay of Bengal, southern slopes of the Himalayas and the South China Sea. Doubling of emissions of both BC and OC aerosols over Southeast Asia (10° S–50° N, 65–155° E) shows that lofted aerosols produce significant warming (0.6–1 K) over the Tibetan Plateau (TP) near 400–200 hPa and instability in the middle/upper troposphere. These aerosols enhance radiative heating rates (0.02–0.03 K day−1) near the tropopause. The enhanced carbonaceous aerosols alter aerosol radiative forcing (RF) at the surface by −4.74 ± 1.42 W m−2, at the top of the atmosphere (TOA) by +0.37 ± 0.26 W m−2 and in the atmosphere by +5.11 ± 0.83 W m−2 over the TP and Indo-Gangetic Plain region (15–35° N, 80–110° E). Atmospheric warming increases vertical velocities and thereby cloud ice in the upper troposphere. Aerosol induced anomalous warming over the TP facilitates the relative strengthening of the monsoon Hadley circulation and increases moisture inflow by strengthening the cross-equatorial monsoon jet. This increases precipitation amounts over India (1–4 mm day−1) and eastern China (0.2–2 mm day−1). These results are significant at the 99 % confidence level.

  19. On the Growth of Ternary System HNO3/H2SO4/H2O Aerosol Particles in the Stratosphere

    Science.gov (United States)

    Hamill, Patrick; Tabazadeh, A.; Kinne, S.; Toon, O. B.; Turco, R. P.

    1996-01-01

    We present a study of the growth of ternary solution (nitric acid, sulfuric acid and water) droplets in the stratosphere. The growth mechanism is hetero-molecular condensation in which the particle is assumed to be in equilibrium with environmental water vapor. Model results are in reasonable agreement with the averaged extinction ratio obtained by the SAM II satellite system.

  20. Complex chemical composition of colored surface films formed from reactions of propanal in sulfuric acid at upper troposphere/lower stratosphere aerosol acidities.

    Science.gov (United States)

    Van Wyngarden, A L; Pérez-Montaño, S; Bui, J V H; Li, E S W; Nelson, T E; Ha, K T; Leong, L; Iraci, L T

    Particles in the upper troposphere and lower stratosphere (UT/LS) consist mostly of concentrated sulfuric acid (40-80 wt %) in water. However, airborne measurements have shown that these particles also contain a significant fraction of organic compounds of unknown chemical composition. Acid-catalyzed reactions of carbonyl species are believed to be responsible for significant transfer of gas phase organic species into tropospheric aerosols and are potentially more important at the high acidities characteristic of UT/LS particles. In this study, experiments combining sulfuric acid (H 2 SO 4 ) with propanal and with mixtures of propanal with glyoxal and/or methylglyoxal at acidities typical of UT/LS aerosols produced highly colored surface films (and solutions) that may have implications for aerosol properties. In order to identify the chemical processes responsible for the formation of the surface films, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and 1 H nuclear magnetic resonance (NMR) spectroscopies were used to analyze the chemical composition of the films. Films formed from propanal were a complex mixture of aldol condensation products, acetals and propanal itself. The major aldol condensation products were the dimer (2-methyl-2-pentenal) and 1,3,5-trimethylbenzene that was formed by cyclization of the linear aldol condensation trimer. Additionally, the strong visible absorption of the films indicates that higher-order aldol condensation products must also be present as minor species. The major acetal species were 2,4,6-triethyl-1,3,5-trioxane and longer-chain linear polyacetals which are likely to separate from the aqueous phase. Films formed on mixtures of propanal with glyoxal and/or methylglyoxal also showed evidence of products of cross-reactions. Since cross-reactions would be more likely than self-reactions under atmospheric conditions, similar reactions of aldehydes like propanal with common aerosol organic species like glyoxal

  1. Refinements in the use of equivalent latitude for assimilating sporadic inhomogeneous stratospheric tracer observations, 1: Detecting transport of Pinatubo aerosol across a strong vortex edge

    Directory of Open Access Journals (Sweden)

    P. Good

    2004-01-01

    Full Text Available The use of PV equivalent latitude for assimilating stratospheric tracer observations is discussed - with particular regard to the errors in the equivalent latitude coordinate, and to the assimilation of sparse data. Some example measurements are assimilated: they sample the stratosphere sporadically and inhomogeneously. The aim was to obtain precise information about the isentropic tracer distribution and evolution as a function of equivalent latitude. Precision is important, if transport across barriers like the vortex edge are to be detected directly. The main challenges addressed are the errors in modelled equivalent latitude, and the non-ideal observational sampling. The methods presented allow first some assessment of equivalent latitude errors and a picture of how good or poor the observational coverage is. This information determines choices in the approach for estimating as precisely as possible the true equivalent latitude distribution of the tracer, in periods of good and poor observational coverage. This is in practice an optimisation process, since better understanding of the equivalent latitude distribution of the tracer feeds back into a clearer picture of the errors in the modelled equivalent latitude coordinate. Error estimates constrain the reliability of using equivalent latitude to make statements like 'this observation samples air poleward of the vortex edge' or that of more general model-measurement comparisons. The approach is demonstrated for ground-based lidar soundings of the Mount Pinatubo aerosol cloud, focusing on the 1991-92 arctic vortex edge between 475-520K. Equivalent latitude is estimated at the observation times and locations from Eulerian model tracers initialised with PV and forced by UK Meteorological Office analyses. With the model formulation chosen, it is shown that tracer transport of a few days resulted in an error distribution that was much closer to Gaussian form, although the mean error was not

  2. Aerosol transport model evaluation of an extreme smoke episode in Southeast Asia

    Science.gov (United States)

    Hyer, Edward J.; Chew, Boon Ning

    2010-04-01

    Biomass burning is one of many sources of particulate pollution in Southeast Asia, but its irregular spatial and temporal patterns mean that large episodes can cause acute air quality problems in urban areas. Fires in Sumatra and Borneo during September and October 2006 contributed to 24-h mean PM 10 concentrations above 150 μg m -3 at multiple locations in Singapore and Malaysia over several days. We use the FLAMBE model of biomass burning emissions and the NAAPS model of aerosol transport and evolution to simulate these events, and compare our simulation results to 24-h average PM 10 measurements from 54 stations in Singapore and Malaysia. The model simulation, including the FLAMBE smoke source as well as dust, sulfate, and sea salt aerosol species, was able to explain 50% or more of the variance in 24-h PM 10 observations at 29 of 54 sites. Simulation results indicated that biomass burning smoke contributed to nearly all of the extreme PM 10 observations during September-November 2006, but the exact contribution of smoke was unclear because the model severely underestimated total smoke emissions. Using regression analysis at each site, the bias in the smoke aerosol flux was determined to be a factor of between 2.5 and 10, and an overall factor of 3.5 was estimated. After application of this factor, the simulated smoke aerosol concentration averaged 20% of observed PM 10, and 40% of PM 10 for days with 24-h average concentrations above 150 μg m -3. These results suggest that aerosol transport models can aid analysis of severe pollution events in Southeast Asia, but that improvements are needed in models of biomass burning smoke emissions.

  3. Aerosol composition and microstructure in the smoky atmosphere of Moscow during the August 2010 extreme wildfires

    Science.gov (United States)

    Popovicheva, O. B.; Kistler, M.; Kireeva, E. D.; Persiantseva, N. M.; Timofeev, M. A.; Shoniya, N. K.; Kopeikin, V. M.

    2017-01-01

    This is a comprehensive study of the physicochemical characterization of multicomponent aerosols in the smoky atmosphere of Moscow during the extreme wildfires of August 2010 and against the background atmosphere of August 2011. Thermal-optical analysis, liquid and ion chromatography, IR spectroscopy, and electron microscopy were used to determine the organic content (OC) and elemental content (EC) of carbon, organic/inorganic and ionic compounds, and biomass burning markers (anhydrosaccharides and the potassium ion) and study the morphology and elemental composition of individual particles. It has been shown that the fires are characterized by an increased OC/EC ratio and high concentrations of ammonium, potassium, and sulfate ions in correlation with an increased content of levoglucosan as a marker of biomass burning. The organic compounds containing carbonyl groups point to the process of photochemical aging and the formation of secondary organic aerosols in the urban atmosphere when aerosols are emitted from forest fires. A cluster analysis of individual particles has indicated that when the smokiest atmosphere is characterized by prevailing soot/tar ball particles, which are smoke-emission micromarkers.

  4. Lidar Observations of Aerosol Disturbances of the Stratosphere over Tomsk (56.5∘N; 85.0∘E in Volcanic Activity Period 2006–2011

    Directory of Open Access Journals (Sweden)

    Oleg E. Bazhenov

    2012-01-01

    Full Text Available The lidar measurements (Tomsk: 56.5∘N; 85.0∘E of the optical characteristics of the stratospheric aerosol layer (SAL in the volcanic activity period 2006–2011 are summarized and analyzed. The background SAL state with minimum aerosol content, observed since 1997 under the conditions of long-term volcanically quiet period, was interrupted in October 2006 by series of explosive eruptions of volcanoes of Pacific Ring of Fire: Rabaul (October 2006, New Guinea; Okmok and Kasatochi (July-August 2008, Aleutian Islands; Redoubt (March-April 2009, Alaska; Sarychev Peak (June 2009, Kuril Islands; Grimsvötn (May 2011, Iceland. A short-term and minor disturbance of the lower stratosphere was also observed in April 2010 after eruption of the Icelandic volcano Eyjafjallajokull. The developed regional empirical model of the vertical distribution of background SAL optical characteristics was used to identify the periods of elevated stratospheric aerosol content after each of the volcanic eruptions. Trends of variations in the total ozone content are also considered.

  5. Lightning-produced NOx in an explicit electrical scheme tested in a Stratosphere-Troposphere Experiment: Radiation, Aerosols, and Ozone case study

    Science.gov (United States)

    Barthe, Christelle; Pinty, Jean-Pierre; Mari, CéLine

    2007-02-01

    An explicit lightning-produced nitrogen oxide (LNOx) scheme has been implemented in a 3-D mesoscale model. The scheme is based on the simulation of the electrical state of the cloud and provides a prediction of the temporal and spatial distribution of the lightning flashes. The frequency and the 3-D morphology of the lightning flashes are captured realistically so fresh nitrogen oxide molecules can be added along the complex flash path as a function of the pressure, as suggested by results from laboratory experiments. The scheme is tested on the 10 July 1996 Stratosphere-Troposphere Experiment: Radiation, Aerosols, and Ozone (STERAO) storm. The model reproduces many features of the observed increase of electrical activity and LNOx flux density between the multicell and supercell stages. LNOx dominates the NOx budget in the upper part of the cells with instantaneous peak concentrations exceeding 4 ppbv, as observed. The computed flux of NOx across the anvil shows a mean value of 6 mol m-2 s-1 during the last 90 min of the simulation. This value is remarkably stable and compares favorably with the observations.

  6. Stratospheric changes caused by geoengineering applications: potential repercussions and uncertainties

    Science.gov (United States)

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

    2009-04-01

    , larger injections might be required than previously assumed. Rasch et al. (2008) showed that smaller particles would be advantageous in terms of cooling the surface. However, with a continuous injection of sulphur dioxide into to lower tropical stratosphere aerosol size distributions with mode radii larger than 0.5 microns are likely to form. An additional complication is that the sedimenting particles tend to heat the tropical tropopause region and as a consequence the entry mixing ratio of water vapour increases. For the extreme scenario of 10 Mt/year injection SOCOL predicts an enhancement of the water vapour entry mixing ratio by more than 1 ppmv. This is predicted to have a significant impact on the radiative forcing and the total ozone, because of enhanced heterogeneous reactions and because the increased water vapour intensifies the hydrogen and chlorine catalysed ozone destruction cycles. The intense warming of the lower stratosphere further intensifies the catalytic ozone destruction cycles. Furthermore, the stratospheric circulation is predicted to change due to the strong heating of the lower stratosphere. As a consequence of the intensified meridional temperature gradient the polar vortices are strengthened with enhanced formation of polar stratospheric clouds and ozone depletion. The ozone loss due to changed stratospheric dynamic is four times larger than the ozone loss caused by the increase of aerosol surface for heterogeneous reactions, which would postpone the recovery of the ozone hole even more as already pointed out by Tilmes et al. [2008]. At the same time the uncertainties involved in the different modelling steps are tremendous. Model validation, by comparing model runs of the 1991 Mt. Pinatubo eruption with observations, reveals that the temperature increase in the lower stratosphere and the tropopause region is probably overestimated by SOCOL. Other CCMs show similar behaviour. This lets us conclude that with the present modelling tools we are

  7. Technical Note: A novel rocket-based in situ collection technique for mesospheric and stratospheric aerosol particles

    Directory of Open Access Journals (Sweden)

    W. Reid

    2013-03-01

    Full Text Available A technique for collecting aerosol particles between altitudes of 17 and 85 km is described. Spin-stabilized collection probes are ejected from a sounding rocket allowing for multi-point measurements. Each probe is equipped with 110 collection samples that are 3 mm in diameter. The collection samples are one of three types: standard transmission electron microscopy carbon grids, glass fibre filter paper or silicone gel. Collection samples are exposed over a 50 m to 5 km height range with a total of 45 separate ranges. Post-flight electron microscopy will give size-resolved information on particle number, shape and elemental composition. Each collection probe is equipped with a suite of sensors to capture the probe's status during the fall. Parachute recovery systems along with GPS-based localization will ensure that each probe can be located and recovered for post-flight analysis.

  8. Benefits, risks, and costs of stratospheric geoengineering

    KAUST Repository

    Robock, Alan; Marquardt, Allison; Kravitz, Ben; Stenchikov, Georgiy L.

    2009-01-01

    Injecting sulfate aerosol precursors into the stratosphere has been suggested as a means of geoengineering to cool the planet and reduce global warming. The decision to implement such a scheme would require a comparison of its benefits, dangers

  9. Extremely large anthropogenic-aerosol contribution to total aerosol load over the Bay of Bengal during winter season

    Directory of Open Access Journals (Sweden)

    D. G. Kaskaoutis

    2011-07-01

    Full Text Available Ship-borne observations of spectral aerosol optical depth (AOD have been carried out over the entire Bay of Bengal (BoB as part of the W-ICARB cruise campaign during the period 27 December 2008–30 January 2009. The results reveal a pronounced temporal and spatial variability in the optical characteristics of aerosols mainly due to anthropogenic emissions and their dispersion controlled by local meteorology. The highest aerosol amount, with mean AOD500>0.4, being even above 1.0 on specific days, is found close to the coastal regions in the western and northern parts of BoB. In these regions the Ångström exponent is also found to be high (~1.2–1.25 indicating transport of strong anthropogenic emissions from continental regions, while very high AOD500 (0.39±0.07 and α380–870 values (1.27±0.09 are found over the eastern BoB. Except from the large α380–870 values, an indication of strong fine-mode dominance is also observed from the AOD curvature, which is negative in the vast majority of the cases, suggesting dominance of an anthropogenic-pollution aerosol type. On the other hand, clean maritime conditions are rather rare over the region, while the aerosol types are further examined through a classification scheme based on the relationship between α and dα. It was found that even for the same α values the fine-mode dominance is larger for higher AODs showing the strong continental influence over the marine environment of BoB. Furthermore, there is also an evidence of aerosol-size growth under more turbid conditions indicative of coagulation and/or humidification over specific BoB regions. The results obtained using OPAC model show significant fraction of soot aerosols (~6 %–8 % over the eastern and northwestern BoB, while coarse-mode sea salt particles are found to dominate in the southern parts of BoB.

  10. Extreme testing of undiluted e-cigarette aerosol in vitro using an Ames air-agar-interface technique.

    Science.gov (United States)

    Thorne, D; Hollings, M; Seymour, A; Adamson, J; Dalrymple, A; Ballantyne, M; Gaca, M

    2018-04-01

    There is a growing consensus that e-cigarettes hold the potential for reducing the harm associated with cigarette smoking. Recently published studies have reported in vitro testing of e-cigarettes, demonstrating reduced toxicological and biological effects. Few studies however have reported the use of e-cigarettes under extreme testing conditions. To assess the full mutagenic potential of a commercially available electronic-cigarette (Vype ePen), this study investigated the delivery of aerosol under extreme conditions, using a scaled-down 35 mm plate Ames bacterial reverse mutagenicity assay. S. typhimurium strains TA98, TA100, TA97, TA104 and E. coli WP2 uvrA pKM101 with or without metabolic activation (S9), were employed. Using a modified Vitrocell VC 10 exposure system 0, 180, 360, 540, 720 or 900 puffs of undiluted e-cigarette aerosol was generated and delivered to bacterial cultures aligned to reported human consumption data. The results demonstrate that no mutagenic activity was observed in any strain under any test condition even when exposed to 900 puffs of undiluted e-cigarette aerosols +/- S9. Positive control responses were observed in all strains +/- S9. Nicotine assessments demonstrated an increased and consistent aerosol delivery, with calculated maximum doses of ∼1 mg/mL delivery of nicotine. These data demonstrate the validity of this unique testing approach and adds further information to the growing weight of evidence that e-cigarettes offer substantially reduced exposure when compared to conventional cigarette smoke. For future in vitro assessments of next generation tobacco and nicotine products, the generation, delivery and testing of undiluted aerosols can now be considered. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  11. Different trends in extreme and median surface aerosol extinction coefficients over China inferred from quality-controlled visibility data

    Science.gov (United States)

    Li, Jing; Li, Chengcai; Zhao, Chunsheng

    2018-03-01

    Although the temporal changes in aerosol properties have been widely investigated, the majority of studies has focused on average conditions without much emphasis on the extremes. However, the latter can be more important in terms of human health and climate change. This study uses a previously validated, quality-controlled visibility dataset to investigate the long-term trends (expressed in terms of relative changes) in extreme surface aerosol extinction coefficient (AEC) over China and compares them with the median trends. Two methods are used to independently evaluate the trends, which arrive at consistent results. The signs of extreme and median trends are generally coherent, whereas their magnitudes show distinct spatial and temporal differences. In the 1980s, an overall positive trend is found throughout China with the extreme trend exceeding the mean trend, except for northwest China and the North China Plain. In the 1990s, AEC over northeast and northwest China started to decline while the rest of the country still exhibited an increase. The extreme trends continued to dominate in the south while they yielded to the mean trend in the north. After the year 2000, the extreme trend became weaker than the mean trend overall in terms of both the magnitude and significance level. The annual trend can be primarily attributed to winter and fall trends. The results suggest that the decadal changes in pollution in China may be governed by different mechanisms. Synoptic conditions that often result in extreme air quality changes might have dominated in the 1980s, whereas emission increase might have been the main factor for the 2000s.

  12. An overview of the Stratospheric-Tropospheric Experiment: Radiation, Aerosols, and Ozone (STERAO)-Deep Convection experiment with results for the July 10, 1996 storm

    Science.gov (United States)

    Dye, J. E.; Ridley, B. A.; Skamarock, W.; Barth, M.; Venticinque, M.; Defer, E.; Blanchet, P.; Thery, C.; Laroche, P.; Baumann, K.; Hubler, G.; Parrish, D. D.; Ryerson, T.; Trainer, M.; Frost, G.; Holloway, J. S.; Matejka, T.; Bartels, D.; Fehsenfeld, F. C.; Tuck, A.; Rutledge, S. A.; Lang, T.; Stith, J.; Zerr, R.

    2000-04-01

    The Stratospheric-Tropospheric Experiment: Radiation, Aerosols and Ozone (STERAO)-Deep Convection Field Project with closely coordinated chemical, dynamical, electrical, and microphysical observations was conducted in northeastern Colorado during June and July of 1996 to investigate the production of NOx by lightning, the transport and redistribution of chemical species in the troposphere by thunderstorms, and the temporal evolution of intracloud and cloud-to-ground lightning for evolving storms on the Colorado high plains. Major observations were airborne chemical measurements in the boundary layer, middle and upper troposphere, and thunderstorm anvils; airborne and ground-based Doppler radar measurements; measurement of both intracloud (IC) and cloud-to-ground (CG) lightning flash rates and locations; and multiparameter radar and in situ observations of microphysical structure. Cloud and mesoscale models are being used to synthesize and extend the observations. Herein we present an overview of the project and selected results for an isolated, severe storm that occurred on July 10. Time histories of reflectivity structure, IC and CG lightning flash rates, and chemical measurements in the boundary layer and in the anvil are presented showing large spatial and temporal variations. The observations for one period of time suggest that limited mixing of environmental air into the updraft core occurred during transport from cloud base to the anvil adjacent to the storm core. We deduce that the most likely contribution of lightning to the total NOx observed in the anvil is 60-90% with a minimum of 45%. For the July 10 storm the NOx produced by lightning was almost exclusively from IC flashes with a ratio of IC to total flashes >0.95 throughout most of the storm's lifetime. It is argued that in this storm and probably others, IC flashes can be major contributors to NOx production. Superposition of VHF lightning source locations on Doppler retrieved air motion fields for

  13. Stratospheric H2O

    International Nuclear Information System (INIS)

    Ellsaesser, H.W.

    1979-01-01

    Documentation of the extreme aridity (approx. 3% relative humidity) of the lower stratosphere and the rapid decrease of mixing ratio with height just above the polar tropopause (20-fold in the 1st km) was begun by Dobson et al., (1946) in 1943. They recognized that this extreme and persistent aridity must be dynamically maintained else it would have been wiped out by turbulent diffusion. This led Brewer (1949) to hypothesize a stratospheric circulation in which all air enters through the tropical tropopause where it is freeze dried to a mass mixing ratio of 2 to 3 ppM. This dry air then spreads poleward and descends through the polar tropopauses overpowering upward transport of water vapor by diffusion which would otherwise be permitted by the much warmer temperatures of the polar tropopauses. Questions can indeed be raised as to the absolute magnitudes of stratospheric mixing ratios, the effective temperature of the tropical tropopause cold trap, the reality of winter pole freeze-dry sinks and the representativeness of the available observations suggesting an H 2 O mixing ratio maximum just above the tropical tropopause and a constant mixing ratio from the tropopause to 30 to 35 km. However, no model that better fits all of the available data is available, than does the Brewer (1949) hypothesis coupled with a lower stratosphere winter pole, freeze-dry sink, at least over Antarctica

  14. Long-term evolution of upper stratospheric ozone at selected stations of the Network for the Detection of Stratospheric Change (NDSC)

    NARCIS (Netherlands)

    Steinbrecht, W; Claude, H; Schönenborn, F; McDermid, I S; Leblanc, T; Godin, S; Song, T; Swart, D P J; Meijer, Y J; Bodeker, G E; Connor, B J; Kämpfer, N; Hocke, K; Calisesi, Y; Schneider, N; Noë, J de la; Parrish, A D; Boyd, I S; Brühl, C; Steil, B; Giorgetta, M A; Manzini, E; Thomason, L W; Zawodny, J M; McCormick, M P; Russell, J M; Bhartia, P K; Stolarski, R S; Hollandsworth-Frith, S M

    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

  15. The ASSET intercomparison of stratosphere and lower mesosphere humidity analyses

    Directory of Open Access Journals (Sweden)

    H. E. Thornton

    2009-02-01

    Full Text Available This paper presents results from the first detailed intercomparison of stratosphere-lower mesosphere water vapour analyses; it builds on earlier results from the EU funded framework V "Assimilation of ENVISAT Data" (ASSET project. Stratospheric water vapour plays an important role in many key atmospheric processes and therefore an improved understanding of its daily variability is desirable. With the availability of high resolution, good quality Michelson Interferometer for Passive Atmospheric Sounding (MIPAS water vapour profiles, the ability of four different atmospheric models to assimilate these data is tested. MIPAS data have been assimilated over September 2003 into the models of the European Centre for Medium Range Weather Forecasts (ECMWF, the Belgian Institute for Space and Aeronomy (BIRA-IASB, the French Service d'Aéronomie (SA-IPSL and the UK Met Office. The resultant middle atmosphere humidity analyses are compared against independent satellite data from the Halogen Occultation Experiment (HALOE, the Polar Ozone and Aerosol Measurement (POAM III and the Stratospheric Aerosol and Gas Experiment (SAGE II. The MIPAS water vapour profiles are generally well assimilated in the ECMWF, BIRA-IASB and SA systems, producing stratosphere-mesosphere water vapour fields where the main features compare favourably with the independent observations. However, the models are less capable of assimilating the MIPAS data where water vapour values are locally extreme or in regions of strong humidity gradients, such as the southern hemisphere lower stratosphere polar vortex. Differences in the analyses can be attributed to the choice of humidity control variable, how the background error covariance matrix is generated, the model resolution and its complexity, the degree of quality control of the observations and the use of observations near the model boundaries. Due to the poor performance of the Met Office analyses the results are not included in

  16. The ASSET intercomparison of stratosphere and lower mesosphere humidity analyses

    Science.gov (United States)

    Thornton, H. E.; Jackson, D. R.; Bekki, S.; Bormann, N.; Errera, Q.; Geer, A. J.; Lahoz, W. A.; Rharmili, S.

    2009-02-01

    This paper presents results from the first detailed intercomparison of stratosphere-lower mesosphere water vapour analyses; it builds on earlier results from the EU funded framework V "Assimilation of ENVISAT Data" (ASSET) project. Stratospheric water vapour plays an important role in many key atmospheric processes and therefore an improved understanding of its daily variability is desirable. With the availability of high resolution, good quality Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) water vapour profiles, the ability of four different atmospheric models to assimilate these data is tested. MIPAS data have been assimilated over September 2003 into the models of the European Centre for Medium Range Weather Forecasts (ECMWF), the Belgian Institute for Space and Aeronomy (BIRA-IASB), the French Service d'Aéronomie (SA-IPSL) and the UK Met Office. The resultant middle atmosphere humidity analyses are compared against independent satellite data from the Halogen Occultation Experiment (HALOE), the Polar Ozone and Aerosol Measurement (POAM III) and the Stratospheric Aerosol and Gas Experiment (SAGE II). The MIPAS water vapour profiles are generally well assimilated in the ECMWF, BIRA-IASB and SA systems, producing stratosphere-mesosphere water vapour fields where the main features compare favourably with the independent observations. However, the models are less capable of assimilating the MIPAS data where water vapour values are locally extreme or in regions of strong humidity gradients, such as the southern hemisphere lower stratosphere polar vortex. Differences in the analyses can be attributed to the choice of humidity control variable, how the background error covariance matrix is generated, the model resolution and its complexity, the degree of quality control of the observations and the use of observations near the model boundaries. Due to the poor performance of the Met Office analyses the results are not included in the intercomparison

  17. Laboratory chemistry and stratospheric clouds

    Science.gov (United States)

    Molina, Mario J.

    1989-01-01

    Results are presented from laboratory experiments on the chemistry of ice particles to study the role of HCl and ClONO2 from CFCs in stratospheric ozone depletion over Antarctica. It is found that gaseous HCl is scavenged with high efficiency by the ice and the gas phase chlorine nitrate may react with the HCL-containing ice to produce Cl2. Also, consideration is given ot the behavior of solid nitric acid trihydrate and sulfuric acid aerosols.

  18. Changes in column aerosol optical properties during extreme haze-fog episodes in January 2013 over urban Beijing

    International Nuclear Information System (INIS)

    Yu, Xingna; Kumar, K. Raghavendra; Lü, Rui; Ma, Jia

    2016-01-01

    Several dense haze-fog (HF) episodes were occurred in the North China Plain (NCP), especially over Beijing in January 2013 characterized by a long duration, a large influential region, and an extremely high PM 2.5 values (>500 μg m −3 ). In this study, we present the characteristics of aerosol optical properties and radiative forcing using Cimel sun-sky radiometer measurements during HF and no haze-fog (NHF) episodes occurred over Beijing during 1–31 January, 2013. The respective maximum values of daily mean aerosol optical depth at 440 nm (AOD 440 ) were observed to be 1.21, 1.43, 1.52, and 2.21 occurred on 12, 14 19, and 28 January. It was found that the Ångström exponent (AE) values were almost higher than 1.0 during all the days with its maximum on 26 January (1.53), suggests the dominance of fine-mode particles. The maximum (minimum) aerosol volume size distributions occurred during dense HF (NHF) days with larger particle volumes of fine-mode. The single scattering albedo, asymmetry parameter, and complex refractive index values during HF events suggest the abundance of fine-mode particles from anthropogenic (absorbing) activities mixed with scattering dust particles. The average shortwave direct aerosol radiative forcing (DARF) values at the bottom-of-atmosphere (BOA) during HF and NHF days were estimated to be 112.29 ± 42.18 W m −2 and −58.61 ± 13.09 W m −2 , while at the top-of-atmosphere (TOA) the forcing values were −45.78 ± 22.17 W m −2 and −18.64 ± 5.84 W m −2 , with the corresponding heating rate of 1.61 ± 0.48 K day −1 and 1.12 ± 0.31 K day −1 , respectively. The DARF values retrieved from the AERONET were in good agreement with the SBDART computed both at the TOA (r = 0.95) and the BOA (r = 0.97) over Beijing in January 2013. - Highlights: • Aerosol optical properties were reported during dense haze-fog (HF) episode. • High AE during HF episode observed dominance of fine mode

  19. Changes in column aerosol optical properties during extreme haze-fog episodes in January 2013 over urban Beijing.

    Science.gov (United States)

    Yu, Xingna; Kumar, K Raghavendra; Lü, Rui; Ma, Jia

    2016-03-01

    Several dense haze-fog (HF) episodes were occurred in the North China Plain (NCP), especially over Beijing in January 2013 characterized by a long duration, a large influential region, and an extremely high PM2.5 values (>500 μg m(-3)). In this study, we present the characteristics of aerosol optical properties and radiative forcing using Cimel sun-sky radiometer measurements during HF and no haze-fog (NHF) episodes occurred over Beijing during 1-31 January, 2013. The respective maximum values of daily mean aerosol optical depth at 440 nm (AOD440) were observed to be 1.21, 1.43, 1.52, and 2.21 occurred on 12, 14 19, and 28 January. It was found that the Ångström exponent (AE) values were almost higher than 1.0 during all the days with its maximum on 26 January (1.53), suggests the dominance of fine-mode particles. The maximum (minimum) aerosol volume size distributions occurred during dense HF (NHF) days with larger particle volumes of fine-mode. The single scattering albedo, asymmetry parameter, and complex refractive index values during HF events suggest the abundance of fine-mode particles from anthropogenic (absorbing) activities mixed with scattering dust particles. The average shortwave direct aerosol radiative forcing (DARF) values at the bottom-of-atmosphere (BOA) during HF and NHF days were estimated to be 112.29 ± 42.18 W m(-2) and -58.61 ± 13.09 W m(-2), while at the top-of-atmosphere (TOA) the forcing values were -45.78 ± 22.17 W m(-2) and -18.64 ± 5.84 W m(-2), with the corresponding heating rate of 1.61 ± 0.48 K day(-1) and 1.12 ± 0.31 K day(-1), respectively. The DARF values retrieved from the AERONET were in good agreement with the SBDART computed both at the TOA (r = 0.95) and the BOA (r = 0.97) over Beijing in January 2013. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Sudden Stratospheric Warming Compendium

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sudden Stratospheric Warming Compendium (SSWC) data set documents the stratospheric, tropospheric, and surface climate impacts of sudden stratospheric warmings. This...

  1. Potential impact of carbonaceous aerosol on the upper troposphere and lower stratosphere (UTLS) and precipitation during Asian summer monsoon in a global model simulation

    KAUST Repository

    Fadnavis, Suvarna; Kalita, Gayatry; Kumar, K. Ravi; Gasparini, Blaž; Li, Jui-Lin Frank

    2017-01-01

    The model simulation shows that boundary layer aerosols are transported into the monsoon anticyclone by the strong monsoon convection from the Bay of Bengal, southern slopes of the Himalayas and the South China Sea. Doubling of emissions of both BC and OC aerosols over Southeast Asia (10° S–50° N, 65–155° E) shows that lofted aerosols produce significant warming (0.6–1 K) over the Tibetan Plateau (TP) near 400–200 hPa and instability in the middle/upper troposphere. These aerosols enhance radiative heating rates (0.02–0.03 K day−1) near the tropopause. The enhanced carbonaceous aerosols alter aerosol radiative forcing (RF) at the surface by −4.74 ± 1.42 W m−2, at the top of the atmosphere (TOA) by +0.37 ± 0.26 W m−2 and in the atmosphere by +5.11 ± 0.83 W m−2 over the TP and Indo-Gangetic Plain region (15–35° N, 80–110° E). Atmospheric warming increases vertical velocities and thereby cloud ice in the upper troposphere. Aerosol induced anomalous warming over the TP facilitates the relative strengthening of the monsoon Hadley circulation and increases moisture inflow by strengthening the cross-equatorial monsoon jet. This increases precipitation amounts over India (1–4 mm day−1) and eastern China (0.2–2 mm day−1). These results are significant at the 99 % confidence level.

  2. The effect of stratospheric sulfur from Mount Pinatubo on tropospheric oxidizing capacity and methane

    NARCIS (Netherlands)

    Bândə, Narcisa; Krol, Maarten; Noije, Van Twan; Weele, Van Michiel; Williams, Jason E.; Sager, Philippe Le; Niemeier, Ulrike; Thomason, Larry; Röckmann, Thomas

    2015-01-01

    The eruption of Mount Pinatubo in 1991 injected a large amount of SO2 into the stratosphere, which formed sulfate aerosols. Increased scattering and absorption of UV radiation by the enhanced stratospheric SO2 and aerosols decreased the amount of UV radiation reaching the

  3. The effect of stratospheric sulfur from Mount Pinatubo on tropospheric oxidizing capacity and methane

    NARCIS (Netherlands)

    Banda, Narcissa; Krol, Maarten; van Noije, Twan; van Weele, Michiel; Williams, Jason E.; Sager, Philippe Le; Niemeier, Ulrike; Thomason, Larry; Röckmann, Thomas

    2015-01-01

    The eruption of Mount Pinatubo in 1991 injected a large amount of SO2 into the stratosphere, which formed sulfate aerosols. Increased scattering and absorption of UV radiation by the enhanced stratospheric SO2 and aerosols decreased the amount of UV radiation reaching the troposphere, causing

  4. Aerosol vertical distribution characteristics over the Tibetan Plateau

    International Nuclear Information System (INIS)

    Deng, Z Q; Han, Y X; Zhao, Q; Li, J

    2014-01-01

    The Stratospheric Aerosol and Gas Experiment II (SAGE II) aerosol products are widely used in climatic characteristic studies and stratospheric aerosol pattern research. Some SAGE II products, e.g., temperature, aerosol surface area density, 1020 nm aerosol extinction coefficient and dust storm frequency, from ground-based observations were analysed from 1984 to 2005. This analysis explored the time and spatial variations of tropospheric and stratospheric aerosols on the Tibet Plateau. The stratospheric aerosol extinction coefficient increased more than two orders of magnitude because of a large volcanic eruption. However, the tropospheric aerosol extinction coefficient decreased over the same period. Removing the volcanic eruption effect, the correlation coefficient for stratospheric AOD (Aerosol Optical Depth) and tropospheric AOD was 0.197. Moreover, the correlation coefficient for stratospheric AOD and dust storm frequency was 0.315. The maximum stratospheric AOD was attained in January, the same month as the tropospheric AOD, when the Qaidam Basin was the centre of low tropospheric AOD and the large mountains coincided with high stratospheric AOD. The vertical structure generated by westerly jet adjustment and the high altitude of the underlying surface of the Tibetan Plateau were important factors affecting winter stratospheric aerosols

  5. Effects of NO{sub x} and SO{sub 2} injections by supersonic aviation on sulfate aerosol and ozone in the troposphere and stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Dyominov, I.G.; Zadorozhny, A.M. [Novosibirsk State Univ. (Russian Federation); Elansky, N.F. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Atmospheric Physics

    1997-12-31

    The impact of supersonic aviation on atmospheric ozone and sulfate aerosol is examined with the help of a two-dimensional dynamical/radiative/chemical model of ozonosphere including aerosol physics. For SO{sub 2} emissions from aircraft as gas, gas/particles (90%/10%) mix, and particles of 0.01 {mu}m radius the sulphate aerosol surface density at maximum of changes increases against its background value by {approx}50%, {approx}75%, and {approx}200%, respectively. This effect of SO{sub 2} emissions with insignificant NO{sub x} injection leads to a significant decrease of total ozone by 2015 in the entire atmosphere. For NO{sub x} emissions which are anticipated in future (EI(NO{sub x}) = 15) any kind of SO{sub 2} emission results in significant weakening of supersonic aviation impact on ozone layer in the Northern Hemisphere. (author) 14 refs.

  6. Effects of NO{sub x} and SO{sub 2} injections by supersonic aviation on sulfate aerosol and ozone in the troposphere and stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Dyominov, I G; Zadorozhny, A M [Novosibirsk State Univ. (Russian Federation); Elansky, N F [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Atmospheric Physics

    1998-12-31

    The impact of supersonic aviation on atmospheric ozone and sulfate aerosol is examined with the help of a two-dimensional dynamical/radiative/chemical model of ozonosphere including aerosol physics. For SO{sub 2} emissions from aircraft as gas, gas/particles (90%/10%) mix, and particles of 0.01 {mu}m radius the sulphate aerosol surface density at maximum of changes increases against its background value by {approx}50%, {approx}75%, and {approx}200%, respectively. This effect of SO{sub 2} emissions with insignificant NO{sub x} injection leads to a significant decrease of total ozone by 2015 in the entire atmosphere. For NO{sub x} emissions which are anticipated in future (EI(NO{sub x}) = 15) any kind of SO{sub 2} emission results in significant weakening of supersonic aviation impact on ozone layer in the Northern Hemisphere. (author) 14 refs.

  7. Extreme ozone depletion in the 2010–2011 Arctic winter stratosphere as observed by MIPAS/ENVISAT using a 2-D tomographic approach

    Directory of Open Access Journals (Sweden)

    E. Arnone

    2012-10-01

    Full Text Available We present observations of the 2010–2011 Arctic winter stratosphere from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS onboard ENVISAT. Limb sounding infrared measurements were taken by MIPAS during the Northern polar winter and into the subsequent spring, giving a continuous vertically resolved view of the Arctic dynamics, chemistry and polar stratospheric clouds (PSCs. We adopted a 2-D tomographic retrieval approach to account for the strong horizontal inhomogeneity of the atmosphere present under vortex conditions, self-consistently comparing 2011 to the 2-D analysis of 2003–2010. Unlike most Arctic winters, 2011 was characterized by a strong stratospheric vortex lasting until early April. Lower stratospheric temperatures persistently remained below the threshold for PSC formation, extending the PSC season up to mid-March, resulting in significant chlorine activation leading to ozone destruction. On 3 January 2011, PSCs were detected up to 30.5 ± 0.9 km altitude, representing the highest PSCs ever reported in the Arctic. Through inspection of MIPAS spectra, 83% of PSCs were identified as supercooled ternary solution (STS or STS mixed with nitric acid trihydrate (NAT, 17% formed mostly by NAT particles, and only two cases by ice. In the lower stratosphere at potential temperature 450 K, vortex average ozone showed a daily depletion rate reaching 100 ppbv day−1. In early April at 18 km altitude, 10% of vortex measurements displayed total depletion of ozone, and vortex average values dropped to 0.6 ppmv. This corresponds to a chemical loss from early winter greater than 80%. Ozone loss was accompanied by activation of ClO, associated depletion of its reservoir ClONO2, and significant denitrification, which further delayed the recovery of ozone in spring. Once the PSC season halted, ClO was reconverted primarily into ClONO2. Compared to MIPAS observed 2003–2010 Arctic average values

  8. Benefits, risks, and costs of stratospheric geoengineering

    KAUST Repository

    Robock, Alan

    2009-10-02

    Injecting sulfate aerosol precursors into the stratosphere has been suggested as a means of geoengineering to cool the planet and reduce global warming. The decision to implement such a scheme would require a comparison of its benefits, dangers, and costs to those of other responses to global warming, including doing nothing. Here we evaluate those factors for stratospheric geoengineering with sulfate aerosols. Using existing U.S. military fighter and tanker planes, the annual costs of injecting aerosol precursors into the lower stratosphere would be several billion dollars. Using artillery or balloons to loft the gas would be much more expensive. We do not have enough information to evaluate more exotic techniques, such as pumping the gas up through a hose attached to a tower or balloon system. Anthropogenic stratospheric aerosol injection would cool the planet, stop the melting of sea ice and land-based glaciers, slow sea level rise, and increase the terrestrial carbon sink, but produce regional drought, ozone depletion, less sunlight for solar power, and make skies less blue. Furthermore it would hamper Earth-based optical astronomy, do nothing to stop ocean acidification, and present many ethical and moral issues. Further work is needed to quantify many of these factors to allow informed decision-making.

  9. Tiny Ultraviolet Polarimeter for Earth Stratosphere from Space Investigation

    Science.gov (United States)

    Nevodovskyi, P. V.; Morozhenko, O. V.; Vidmachenko, A. P.; Ivakhiv, O.; Geraimchuk, M.; Zbrutskyi, O.

    2015-09-01

    One of the reasons for climate change (i.e., stratospheric ozone concentrations) is connected with the variations in optical thickness of aerosols in the upper sphere of the atmosphere (at altitudes over 30 km). Therefore, aerosol and gas components of the atmosphere are crucial in the study of the ultraviolet (UV) radiation passing upon the Earth. Moreover, a scrupulous study of aerosol components of the Earth atmosphere at an altitude of 30 km (i.e., stratospheric aerosol), such as the size of particles, the real part of refractive index, optical thickness and its horizontal structure, concentration of ozone or the upper border of the stratospheric ozone layer is an important task in the research of the Earth climate change. At present, the Main Astronomical Observatory of the National Academy of Sciences (NAS) of Ukraine, the National Technical University of Ukraine "KPI"and the Lviv Polytechnic National University are engaged in the development of methodologies for the study of stratospheric aerosol by means of ultraviolet polarimeter using a microsatellite. So fare, there has been created a sample of a tiny ultraviolet polarimeter (UVP) which is considered to be a basic model for carrying out space experiments regarding the impact of the changes in stratospheric aerosols on both global and local climate.

  10. New stratospheric UV/visible radiance measurements

    Directory of Open Access Journals (Sweden)

    F. J. Marceau

    1994-01-01

    Full Text Available A stratospheric balloon was launched on 12 October 1986 from the "CNES" base at Aire sur l'Adour (France to record twilight radiance in the stratosphere. The near-UV and visible radiances were continuously monitored by a photometer during sunrise. Some observations are presented for different viewing azimuthal planes and viewing elevation angles. They show the influence of aerosols layers and clouds which can be also seen on related photographs. The results as a whole may be used for testing some radiative models, especially for twilight conditions.

  11. Mount St. Helens aerosol evolution

    Energy Technology Data Exchange (ETDEWEB)

    Oberbeck, V.R.; Farlow, N.H.

    1982-08-01

    Stratospheric aerosol samples were collected using a wire impactor during the year following the eruption of Mount St. Helens. Analysis of samples shows that aerosol volume increased for 6 months due to gas-to-particle conversion and then decreased to background levels in the following 6 months.

  12. Mount St. Helens aerosol evolution

    Energy Technology Data Exchange (ETDEWEB)

    Oberbeck, V.R.; Farlow, N.H.; Fong, W.; Snetsinger, K.G.; Ferry, G.V.; Hayes, D.M.

    1982-09-01

    Stratospheric aerosol samples were collected using a wire impactor during the year following the eruption of Mt. St. Helens. Analysis of samples show that aerosol volume increased for 6 months due to gas-to-particle conversion and then decreased to background levels in the following 6 months.

  13. Stratospheric Platforms for Monitoring Purposes

    International Nuclear Information System (INIS)

    Konigorski, D.; Gratzel, U.; Obersteiner, M.; Schneidereit, M.

    2010-01-01

    ) incrementally, e.g. by deploying additional High Altitude Platforms (HAPs); Ability to service / update / reconfigure payload; Close range - for both monitoring and communications: 1. Monitoring from e.g. 20 km distance, compared with about 450 km for a Low Earth Orbit (LEO) satellite. Furthermore the platforms facilitate very high spatial resolution. 2. Extremely high overall payload and power capacity and can replace extensive ground infrastructure (e.g. telecoms masts); Stratospheric platforms can also make use of low temperatures (superconducting), large antennas (high resolution), less atmosphere (high power microwave) and energy collection and transmission (electric power support of high altitude UAVs). The paper will discuss the potential of stratospheric platforms for safeguards applications. (author)

  14. How stratospheric are deep stratospheric intrusions? LUAMI 2008

    Directory of Open Access Journals (Sweden)

    T. Trickl

    2016-07-01

    Full Text Available A large-scale comparison of water-vapour vertical-sounding instruments took place over central Europe on 17 October 2008, during a rather homogeneous deep stratospheric intrusion event (LUAMI, Lindenberg Upper-Air Methods Intercomparison. The measurements were carried out at four observational sites: Payerne (Switzerland, Bilthoven (the Netherlands, Lindenberg (north-eastern Germany, and the Zugspitze mountain (Garmisch-Partenkichen, German Alps, and by an airborne water-vapour lidar system creating a transect of humidity profiles between all four stations. A high data quality was verified that strongly underlines the scientific findings. The intrusion layer was very dry with a minimum mixing ratios of 0 to 35 ppm on its lower west side, but did not drop below 120 ppm on the higher-lying east side (Lindenberg. The dryness hardens the findings of a preceding study (“Part 1”, Trickl et al., 2014 that, e.g., 73 % of deep intrusions reaching the German Alps and travelling 6 days or less exhibit minimum mixing ratios of 50 ppm and less. These low values reflect values found in the lowermost stratosphere and indicate very slow mixing with tropospheric air during the downward transport to the lower troposphere. The peak ozone values were around 70 ppb, confirming the idea that intrusion layers depart from the lowermost edge of the stratosphere. The data suggest an increase of ozone from the lower to the higher edge of the intrusion layer. This behaviour is also confirmed by stratospheric aerosol caught in the layer. Both observations are in agreement with the idea that sections of the vertical distributions of these constituents in the source region were transferred to central Europe without major change. LAGRANTO trajectory calculations demonstrated a rather shallow outflow from the stratosphere just above the dynamical tropopause, for the first time confirming the conclusions in “Part 1” from the Zugspitze CO observations. The

  15. On particles in the Arctic stratosphere

    Directory of Open Access Journals (Sweden)

    T. S. Jørgensen

    2003-06-01

    Full Text Available Soon after the discovery of the Antarctic ozone hole it became clear that particles in the polar stratosphere had an infl uence on the destruction of the ozone layer. Two major types of particles, sulphate aerosols and Polar Stratospheric Clouds (PSCs, provide the surfaces where fast heterogeneous chemical reactions convert inactive halogen reservoir species into potentially ozone-destroying radicals. Lidar measurements have been used to classify the PSCs. Following the Mt. Pinatubo eruption in June 1991 it was found that the Arctic stratosphere was loaded with aerosols, and that aerosols observed with lidar and ozone observed with ozone sondes displayed a layered structure, and that the aerosol and ozone contents in the layers frequently appeared to be negatively correlated. The layered structure was probably due to modulation induced by the dynamics at the edge of the polar vortex. Lidar observations of the Mt. Pinatubo aerosols were in several cases accompanied by balloon-borne backscatter soundings, whereby backscatter measurements in three different wavelengths made it possible to obtain information about the particle sizes. An investigation of the infl uence of synoptic temperature histories on the physical properties of PSC particles has shown that most of the liquid type 1b particles were observed in the process of an ongoing, relatively fast, and continuous cooling from temperatures clearly above the nitric acid trihydrate condensation temperature (TNAT. On the other hand, it appeared that a relatively long period, with a duration of at least 1-2 days, at temperatures below TNAT provide the conditions which may lead to the production of solid type 1a PSCs.

  16. Fossil and non-fossil source contributions to atmospheric carbonaceous aerosols during extreme spring grassland fires in Eastern Europe

    Directory of Open Access Journals (Sweden)

    V. Ulevicius

    2016-05-01

    Full Text Available In early spring the Baltic region is frequently affected by high-pollution events due to biomass burning in that area. Here we present a comprehensive study to investigate the impact of biomass/grass burning (BB on the evolution and composition of aerosol in Preila, Lithuania, during springtime open fires. Non-refractory submicron particulate matter (NR-PM1 was measured by an Aerodyne aerosol chemical speciation monitor (ACSM and a source apportionment with the multilinear engine (ME-2 running the positive matrix factorization (PMF model was applied to the organic aerosol fraction to investigate the impact of biomass/grass burning. Satellite observations over regions of biomass burning activity supported the results and identification of air mass transport to the area of investigation. Sharp increases in biomass burning tracers, such as levoglucosan up to 683 ng m−3 and black carbon (BC up to 17 µg m−3 were observed during this period. A further separation between fossil and non-fossil primary and secondary contributions was obtained by coupling ACSM PMF results and radiocarbon (14C measurements of the elemental (EC and organic (OC carbon fractions. Non-fossil organic carbon (OCnf was the dominant fraction of PM1, with the primary (POCnf and secondary (SOCnf fractions contributing 26–44 % and 13–23 % to the total carbon (TC, respectively. 5–8 % of the TC had a primary fossil origin (POCf, whereas the contribution of fossil secondary organic carbon (SOCf was 4–13 %. Non-fossil EC (ECnf and fossil EC (ECf ranged from 13–24 and 7–13 %, respectively. Isotope ratios of stable carbon and nitrogen isotopes were used to distinguish aerosol particles associated with solid and liquid fossil fuel burning.

  17. Fossil and non-fossil source contributions to atmospheric carbonaceous aerosols during extreme spring grassland fires in Eastern Europe

    Science.gov (United States)

    Ulevicius, Vidmantas; Byčenkienė, Steigvilė; Bozzetti, Carlo; Vlachou, Athanasia; Plauškaitė, Kristina; Mordas, Genrik; Dudoitis, Vadimas; Abbaszade, Gülcin; Remeikis, Vidmantas; Garbaras, Andrius; Masalaite, Agne; Blees, Jan; Fröhlich, Roman; Dällenbach, Kaspar R.; Canonaco, Francesco; Slowik, Jay G.; Dommen, Josef; Zimmermann, Ralf; Schnelle-Kreis, Jürgen; Salazar, Gary A.; Agrios, Konstantinos; Szidat, Sönke; El Haddad, Imad; Prévôt, André S. H.

    2016-05-01

    In early spring the Baltic region is frequently affected by high-pollution events due to biomass burning in that area. Here we present a comprehensive study to investigate the impact of biomass/grass burning (BB) on the evolution and composition of aerosol in Preila, Lithuania, during springtime open fires. Non-refractory submicron particulate matter (NR-PM1) was measured by an Aerodyne aerosol chemical speciation monitor (ACSM) and a source apportionment with the multilinear engine (ME-2) running the positive matrix factorization (PMF) model was applied to the organic aerosol fraction to investigate the impact of biomass/grass burning. Satellite observations over regions of biomass burning activity supported the results and identification of air mass transport to the area of investigation. Sharp increases in biomass burning tracers, such as levoglucosan up to 683 ng m-3 and black carbon (BC) up to 17 µg m-3 were observed during this period. A further separation between fossil and non-fossil primary and secondary contributions was obtained by coupling ACSM PMF results and radiocarbon (14C) measurements of the elemental (EC) and organic (OC) carbon fractions. Non-fossil organic carbon (OCnf) was the dominant fraction of PM1, with the primary (POCnf) and secondary (SOCnf) fractions contributing 26-44 % and 13-23 % to the total carbon (TC), respectively. 5-8 % of the TC had a primary fossil origin (POCf), whereas the contribution of fossil secondary organic carbon (SOCf) was 4-13 %. Non-fossil EC (ECnf) and fossil EC (ECf) ranged from 13-24 and 7-13 %, respectively. Isotope ratios of stable carbon and nitrogen isotopes were used to distinguish aerosol particles associated with solid and liquid fossil fuel burning.

  18. Influence of extreme events on health-related aerosol particle deposition in an urban site during summer

    Science.gov (United States)

    Belmonte, Paula; Castro, Amaya; Calvo, Ana Isabel; Alves, Célia; Duarte, Márcio; Alonso-Blanco, Elisabeth; Fraile, Roberto

    2014-05-01

    Urban populations are exposed to aerosol particles that enter in the human respiratory track posing an important risk to human health. Particle sampling conventions have been established, expressed as curves describing "penetration" to the region of interest in terms of the particle aerodynamic diameter. The inhalable, thoracic, traqueo-bronchial and respirable fractions have been estimated according to the International Standard ISO 7708:1995. This study presents the analysis of aerosol size distributions and its deposition in the human respiratory tract according to ISO 7708. The influence of ambient conditions in an urban area affected by heat waves and wildfires in the summer months has been analyzed. A laser spectrometer PCASP-X was used to characterize the aerosol size distributions. This device registers particle sizes between 0.1 and 10 microns in 31 channels. The spectrometer was installed in the city of León (Spain), between June and September 2012, and 24 measurements were carried out daily to determine the size of the ambient particles in the urban area. The measurements were averaged over 15-minute intervals. A weather station was installed at 3 m above the ground to register automatically data on precipitation, pressure, temperature, relative humidity wind speed and direction. The refractive index of the particles was estimated for each value of relative humidity, as the relative humidity of the ambient atmosphere affects the size and the complex refractive index of aerosols. Afterwards, raw size bins were corrected from the estimated refractive indices using a program based on Mie Theory. The regional government provided data on the exact location of summer wildfires in the province of Leon, as well as data on the land area affected. A persistent and intense thermal inversion of subsidence caused an intense pollution episode in the city during the main wildfire, which broke out at a distance of about 60 km from the sampling point. Furthermore, the

  19. Stratospheric dryness: model simulations and satellite observations

    Directory of Open Access Journals (Sweden)

    J. Lelieveld

    2007-01-01

    Full Text Available The mechanisms responsible for the extreme dryness of the stratosphere have been debated for decades. A key difficulty has been the lack of comprehensive models which are able to reproduce the observations. Here we examine results from the coupled lower-middle atmosphere chemistry general circulation model ECHAM5/MESSy1 together with satellite observations. Our model results match observed temperatures in the tropical lower stratosphere and realistically represent the seasonal and inter-annual variability of water vapor. The model reproduces the very low water vapor mixing ratios (below 2 ppmv periodically observed at the tropical tropopause near 100 hPa, as well as the characteristic tape recorder signal up to about 10 hPa, providing evidence that the dehydration mechanism is well-captured. Our results confirm that the entry of tropospheric air into the tropical stratosphere is forced by large-scale wave dynamics, whereas radiative cooling regionally decelerates upwelling and can even cause downwelling. Thin cirrus forms in the cold air above cumulonimbus clouds, and the associated sedimentation of ice particles between 100 and 200 hPa reduces water mass fluxes by nearly two orders of magnitude compared to air mass fluxes. Transport into the stratosphere is supported by regional net radiative heating, to a large extent in the outer tropics. During summer very deep monsoon convection over Southeast Asia, centered over Tibet, moistens the stratosphere.

  20. Forcing of stratospheric chemistry and dynamics during the Dalton Minimum

    Science.gov (United States)

    Anet, J. G.; Muthers, S.; Rozanov, E.; Raible, C. C.; Peter, T.; Stenke, A.; Shapiro, A. I.; Beer, J.; Steinhilber, F.; Brönnimann, S.; Arfeuille, F.; Brugnara, Y.; Schmutz, W.

    2013-11-01

    The response of atmospheric chemistry and dynamics to volcanic eruptions and to a decrease in solar activity during the Dalton Minimum is investigated with the fully coupled atmosphere-ocean chemistry general circulation model SOCOL-MPIOM (modeling tools for studies of SOlar Climate Ozone Links-Max Planck Institute Ocean Model) covering the time period 1780 to 1840 AD. We carried out several sensitivity ensemble experiments to separate the effects of (i) reduced solar ultra-violet (UV) irradiance, (ii) reduced solar visible and near infrared irradiance, (iii) enhanced galactic cosmic ray intensity as well as less intensive solar energetic proton events and auroral electron precipitation, and (iv) volcanic aerosols. The introduced changes of UV irradiance and volcanic aerosols significantly influence stratospheric dynamics in the early 19th century, whereas changes in the visible part of the spectrum and energetic particles have smaller effects. A reduction of UV irradiance by 15%, which represents the presently discussed highest estimate of UV irradiance change caused by solar activity changes, causes global ozone decrease below the stratopause reaching as much as 8% in the midlatitudes at 5 hPa and a significant stratospheric cooling of up to 2 °C in the mid-stratosphere and to 6 °C in the lower mesosphere. Changes in energetic particle precipitation lead only to minor changes in the yearly averaged temperature fields in the stratosphere. Volcanic aerosols heat the tropical lower stratosphere, allowing more water vapour to enter the tropical stratosphere, which, via HOx reactions, decreases upper stratospheric and mesospheric ozone by roughly 4%. Conversely, heterogeneous chemistry on aerosols reduces stratospheric NOx, leading to a 12% ozone increase in the tropics, whereas a decrease in ozone of up to 5% is found over Antarctica in boreal winter. The linear superposition of the different contributions is not equivalent to the response obtained in a simulation

  1. Tales of volcanoes and El-Nino southern oscillations with the oxygen isotope anomaly of sulfate aerosol.

    Science.gov (United States)

    Shaheen, Robina; Abauanza, Mariana; Jackson, Teresa L; McCabe, Justin; Savarino, Joel; Thiemens, Mark H

    2013-10-29

    The ability of sulfate aerosols to reflect solar radiation and simultaneously act as cloud condensation nuclei renders them central players in the global climate system. The oxidation of S(IV) compounds and their transport as stable S(VI) in the Earth's system are intricately linked to planetary scale processes, and precise characterization of the overall process requires a detailed understanding of the linkage between climate dynamics and the chemistry leading to the product sulfate. This paper reports a high-resolution, 22-y (1980-2002) record of the oxygen-triple isotopic composition of sulfate (SO4) aerosols retrieved from a snow pit at the South Pole. Observed variation in the O-isotopic anomaly of SO4 aerosol is linked to the ozone variation in the tropical upper troposphere/lower stratosphere via the Ozone El-Niño Southern Oscillations (ENSO) Index (OEI). Higher (17)O values (3.3‰, 4.5‰, and 4.2‰) were observed during the three largest ENSO events of the past 2 decades. Volcanic events inject significant quantities of SO4 aerosol into the stratosphere, which are known to affect ENSO strength by modulating stratospheric ozone levels (OEI = 6 and (17)O = 3.3‰, OEI = 11 and (17)O = 4.5‰) and normal oxidative pathways. Our high-resolution data indicated that (17)O of sulfate aerosols can record extreme phases of naturally occurring climate cycles, such as ENSOs, which couple variations in the ozone levels in the atmosphere and the hydrosphere via temperature driven changes in relative humidity levels. A longer term, higher resolution oxygen-triple isotope analysis of sulfate aerosols from ice cores, encompassing more ENSO periods, is required to reconstruct paleo-ENSO events and paleotropical ozone variations.

  2. Stratospheric sulfur and its implications for radiative forcing simulated by the chemistry climate model EMAC.

    Science.gov (United States)

    Brühl, C; Lelieveld, J; Tost, H; Höpfner, M; Glatthor, N

    2015-03-16

    Multiyear simulations with the atmospheric chemistry general circulation model EMAC with a microphysical modal aerosol module at high vertical resolution demonstrate that the sulfur gases COS and SO 2 , the latter from low-latitude and midlatitude volcanic eruptions, predominantly control the formation of stratospheric aerosol. Marine dimethyl sulfide (DMS) and other SO 2 sources, including strong anthropogenic emissions in China, are found to play a minor role except in the lowermost stratosphere. Estimates of volcanic SO 2 emissions are based on satellite observations using Total Ozone Mapping Spectrometer and Ozone Monitoring Instrument for total injected mass and Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat or Stratospheric Aerosol and Gases Experiment for the spatial distribution. The 10 year SO 2 and COS data set of MIPAS is also used for model evaluation. The calculated radiative forcing of stratospheric background aerosol including sulfate from COS and small contributions by DMS oxidation, and organic aerosol from biomass burning, is about 0.07W/m 2 . For stratospheric sulfate aerosol from medium and small volcanic eruptions between 2005 and 2011 a global radiative forcing up to 0.2W/m 2 is calculated, moderating climate warming, while for the major Pinatubo eruption the simulated forcing reaches 5W/m 2 , leading to temporary climate cooling. The Pinatubo simulation demonstrates the importance of radiative feedback on dynamics, e.g., enhanced tropical upwelling, for large volcanic eruptions.

  3. Chlorine in the stratosphere

    OpenAIRE

    VON CLARMANN, T.

    2013-01-01

    This paper reviews the various aspects of chlorine compounds in the stratosphere, both their roles as reactants and as tracers of dynamical processes. In the stratosphere, reactive chlorine is released from chlorofluorocarbons and other chlorine-containing organic source gases. To a large extent reactive chlorine is then sequestered in reservoir species ClONO2 and HCl. Re-activation of chlorine happens predominantly in polar winter vortices by heterogeneous reaction in combination with sunlig...

  4. Impact of major volcanic eruptions on stratospheric water vapour

    Directory of Open Access Journals (Sweden)

    M. Löffler

    2016-05-01

    Full Text Available Volcanic eruptions can have a significant impact on the Earth's weather and climate system. Besides the subsequent tropospheric changes, the stratosphere is also influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry–climate model simulations. This study is based on two simulations with specified dynamics of the European Centre for Medium-Range Weather Forecasts Hamburg – Modular Earth Submodel System (ECHAM/MESSy Atmospheric Chemistry (EMAC model, performed within the Earth System Chemistry integrated Modelling (ESCiMo project, of which only one includes the long-wave volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour induced by the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on tropospheric water vapour and El Niño–Southern Oscillation (ENSO are evident, if the long-wave forcing is strong enough. Our results are corroborated by additional sensitivity simulations of the Mount Pinatubo period with reduced nudging and reduced volcanic aerosol extinction.

  5. Simulations of Sulfate-Nitrate-Ammonium (SNA) aerosols during the extreme haze events over Northern China in 2014

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dan; Liu, Zhiquan; Fast, Jerome D.; Ban, Junmei

    2016-08-30

    Extreme haze events have occurred frequently over China in recent years. Although many studies have investigated the formation mechanisms associated with PM2.5 for heavily polluted regions in China based on observational data, adequately predicting peak PM2.5 concentrations is still challenging for regional air quality models. In this study, we evaluate the performance of one configuration of the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) and use the model to investigate the sensitivity of heterogeneous reactions on simulated peak sulfate, nitrate, and ammonium concentrations in the vicinity of Beijing during four extreme haze episodes in October 2014 over the North China Plain. The highest observed PM2.5 concentration of 469 μg m-3 occurred in Beijing. Comparisons with observations show that the model reproduced the temporal variability in PM2.5 with the highest PM2.5 values on polluted days (defined as days in which observed PM2.5 is greater than 75 μg m-3), but predictions of sulfate, nitrate, and ammonium were too low on days with the highest observed concentrations. Observational data indicate that the sulfur/nitric oxidation rates are strongly correlated with relative humidity during periods of peak PM2.5; however, the model failed to reproduce the highest PM2.5 concentrations due to missing heterogeneous reactions. As the parameterizations of those reactions is not well established yet, estimates of SO2-to-H2SO4 and NO2/NO3-to-HNO3 reaction rates that depend on relative humidity were applied which improved the simulation of sulfate, nitrate, and ammonium enhancement on polluted days in terms of both concentrations and partitioning among those species. Sensitivity simulations showed that the extremely high heterogeneous reaction rates and also higher emission rates than those reported in the emission inventory

  6. Heterogeneous Formation of Polar Stratospheric Clouds- Part 1: Nucleation of Nitric Acid Trihydrate (NAT)

    Science.gov (United States)

    Hoyle, C. R.; Engel, I.; Luo, B. P.; Pitts, M. C.; Poole, L. R.; Grooss, J.-U.; Peter, T.

    2013-01-01

    Satellite-based observations during the Arctic winter of 2009/2010 provide firm evidence that, in contrast to the current understanding, the nucleation of nitric acid trihydrate (NAT) in the polar stratosphere does not only occur on preexisting ice particles. In order to explain the NAT clouds observed over the Arctic in mid-December 2009, a heterogeneous nucleation mechanism is required, occurring via immersion freezing on the surface of solid particles, likely of meteoritic origin. For the first time, a detailed microphysical modelling of this NAT formation pathway has been carried out. Heterogeneous NAT formation was calculated along more than sixty thousand trajectories, ending at Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) observation points. Comparing the optical properties of the modelled NAT with these observations enabled a thorough validation of a newly developed NAT nucleation parameterisation, which has been built into the Zurich Optical and Microphysical box Model (ZOMM). The parameterisation is based on active site theory, is simple to implement in models and provides substantial advantages over previous approaches which involved a constant rate of NAT nucleation in a given volume of air. It is shown that the new method is capable of reproducing observed polar stratospheric clouds (PSCs) very well, despite the varied conditions experienced by air parcels travelling along the different trajectories. In a companion paper, ZOMM is applied to a later period of the winter, when ice PSCs are also present, and it is shown that the observed PSCs are also represented extremely well under these conditions.

  7. Instrumentation for tropospheric aerosol characterization

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Z.; Young, S.E.; Becker, C.H.; Coggiola, M.J. [SRI International, Menlo Park, CA (United States); Wollnik, H. [Giessen Univ. (Germany)

    1997-12-31

    A new instrument has been developed that determines the abundance, size distribution, and chemical composition of tropospheric and lower stratospheric aerosols with diameters down to 0.2 {mu}m. In addition to aerosol characterization, the instrument also monitors the chemical composition of the ambient gas. More than 25.000 aerosol particle mass spectra were recorded during the NASA-sponsored Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) field program using NASA`s DC-8 research aircraft. (author) 7 refs.

  8. Instrumentation for tropospheric aerosol characterization

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Z; Young, S E; Becker, C H; Coggiola, M J [SRI International, Menlo Park, CA (United States); Wollnik, H [Giessen Univ. (Germany)

    1998-12-31

    A new instrument has been developed that determines the abundance, size distribution, and chemical composition of tropospheric and lower stratospheric aerosols with diameters down to 0.2 {mu}m. In addition to aerosol characterization, the instrument also monitors the chemical composition of the ambient gas. More than 25.000 aerosol particle mass spectra were recorded during the NASA-sponsored Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) field program using NASA`s DC-8 research aircraft. (author) 7 refs.

  9. Size-resolved aerosol chemical analysis of extreme haze pollution events during early 2013 in urban Beijing, China

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Shili; Pan, Yuepeng, E-mail: panyuepeng@mail.iap.ac.cn; Liu, Zirui; Wen, Tianxue; Wang, Yuesi, E-mail: wys@mail.iap.ac.cn

    2014-08-30

    Highlights: • Anthropogenic species substantially accumulated in both fine and coarse particles. • Secondary organic carbon in PM{sub 1.1} decreased from clear to haze days. • The mass peak shifted to larger particles from clear to haze days. • The NO{sub 3}{sup −}/SO{sub 4}{sup 2−} ratio decreased with enhanced haze pollution. • Both mobile local and stationary regional sources were vital for haze formation. - Abstract: Using size-resolved filter sampling and chemical characterization, high concentrations of water-soluble ions, carbonaceous species and heavy metals were found in both fine (PM{sub 2.1}) and coarse (PM{sub 2.1–9}) particles in Beijing during haze events in early 2013. Even on clear days, average mass concentration of submicron particles (PM{sub 1.1}) was several times higher than that previously measured in most of abroad urban areas. A high concentration of particulate matter on haze days weakens the incident solar radiation, which reduces the generation rate of secondary organic carbon in PM{sub 1.1}. We show that the peak mass concentration of particles shifted from 0.43–0.65 μm on clear days to 0.65–1.1 μm on lightly polluted days and to 1.1–2.1 μm on heavily polluted days. The peak shifts were also found for the following species: organic carbon, elemental carbon, NH{sub 4}{sup +}, SO{sub 4}{sup 2−}, NO{sub 3}{sup −}, K, Cu, Zn, Cd and Pb. Our findings demonstrate that secondary inorganic aerosols (36%) and organic matter (26%) dominated the fine particle mass on heavily polluted days, while their contribution reduced to 29% and 18%, respectively, on clear days. Besides fine particles, anthropogenic chemical species also substantially accumulated in the coarse mode, which suggests that particles with aerodynamic diameter larger than 2.1 μm cannot be neglected during severe haze events.

  10. Decade of stratospheric sulfate measurements compared with observations of volcanic eruptions

    International Nuclear Information System (INIS)

    Sedlacek, W.A.; Mroz, E.J.; Lazrus, A.L.; Gandrud, B.W.

    1983-01-01

    Sulfate aerosol concentrations in the stratosphere have been measured for 11 years (1971--1981) using portions of filters collected by the Department of Energy's High Altitude Sampling Program. Data collected seasonally at altitudes between 13 km and 20 km spanning latitudes from 75 0 N to 51 0 S are reported. These data are compared with the reported altitudes of volcanic eruption plumes during the same decade. From this comparison it is concluded that (1) several unreported volcanic eruptions or eruptions to altitudes higher than reported did occur during the decade, (2) the e-fold removal time for sulfate aerosol from the stratosphere following the eruption of Volcan Fuego in 1974 was 11.2 +- 1.2 months, (3) the volcanic contribution to the average stratospheric sulfate concentration over the decade was greater than 50%, and (4) there may be evidence for an anthropogenic contribution to stratospheric sulfate that increases at the rate of 6 to 8% per year

  11. Persistence of Antarctic polar stratospheric clouds

    Science.gov (United States)

    Mccormick, M. Patrick; Trepte, C. R.

    1988-01-01

    The persistence of Polar Stratospheric Clouds (PSCs) observed by the Stratospheric Aerosol Measurement (SAM) 2 satellite sensor over a 9-year period is compared and contrasted. Histograms of the SAM 2 1.0 micron extinction ratio data (aerosol extinction normalized by the molecular extinction) at an altitude of 18 km in the Antarctic have been generated for three 10-day periods in the month of September. Statistics for eight different years (1979 to 1982 and 1984 to 1987) are shown in separate panels for each figure. Since the SAM 2 system is a solar occultation experiment, observations are limited to the edge of the polar night and no measurements are made deep within the vortex where temperatures could be colder. For this reason, use is made of the NMC global gridded fields and the known temperature-extinction relationship to infer additional information on the occurrence and areal coverage of PSCs. Calculations of the daily areal coverage of the 195 K isotherm will be presented for this same period of data. This contour level lies in the range of the predicted temperature for onset of the Type 1 particle enhancement mode at 50 mb (Poole and McCormick, 1988b) and should indicate approximately when formation of the binary HNO3-H2O particles begins.

  12. SAM II aerosol profile measurements, Poker Flat, Alaska; July 16-19, 1979

    Science.gov (United States)

    Mccormick, M. P.; Chu, W. P.; Mcmaster, L. R.; Grams, G. W.; Herman, B. M.; Pepin, T. J.; Russell, P. B.; Swissler, T. J.

    1981-01-01

    SAM II satellite measurements during the July 1979 Poker Flat mission, yielded an aerosol extinction coefficient of 0.0004/km at 1.0 micron wavelength, in the region of the stratospheric aerosol mixing ratio peak (12-16 km). The stratospheric aerosol optical depth for these data, calculated from the tropopause through 30 km, is approximately 0.001. These results are consistent with the average 1979 summertime values found throughout the Arctic.

  13. H2SO4-HNO3-H2O ternary system in the stratosphere

    Science.gov (United States)

    Kiang, C. S.; Hamill, P.

    1974-01-01

    Estimation of the equilibrium vapor pressure over the ternary system H2SO4-HNO3-H2O to study the possibility of stratospheric aerosol formation involving HNO3. It is shown that the vapor pressures for the ternary system H2SO4-HNO3-H2O with weight composition around 70-80% H2SO4, 10-20% HNO3, 10-20% H2O at -50 C are below the order of 10 to the minus 8th mm Hg. It is concluded that there exists more than sufficient nitric acid and water vapor in the stratosphere to participate in ternary system aerosol formation at -50 C. Therefore, HNO3 should be present in stratospheric aerosols, provided that H2SO4 is also present.

  14. The global warming potential of methane reassessed with combined stratosphere and troposphere chemistry

    Science.gov (United States)

    Holmes, C. D.; Archibald, A. T.; Eastham, S. D.; Søvde, O. A.

    2017-12-01

    Methane is a direct and indirect greenhouse gas. The direct greenhouse effect comes from the radiation absorbed and emitted by methane itself. The indirect greenhouse effect comes from radiatively active gases that are produced during methane oxidation: principally O3, H2O, and CO2. Methane also suppresses tropospheric OH, which indirectly affects numerous greenhouses gases and aerosols. Traditionally, the methane global warming potential (GWP) has included the indirect effects on tropospheric O3 and OH and stratospheric H2O, with these effects estimated independently from unrelated tropospheric and stratospheric chemistry models and observations. Using this approach the CH4 is about 28 over 100 yr (without carbon cycle feedbacks, IPCC, 2013). Here we present a comprehensive analysis of the CH4 GWP in several 3-D global atmospheric models capable of simulating both tropospheric and stratospheric chemistry (GEOS-Chem, Oslo CTM3, UKCA). This enables us to include, for the first time, the indirect effects of CH4 on stratospheric O3 and stratosphere-troposphere coupling. We diagnose the GWP from paired simulations with and without a 5% perturbation to tropospheric CH4 concentrations. Including stratospheric chemistry nearly doubles the O3 contribution to CH4 GWP because of O3 production in the lower stratosphere and because CH4 inhibits Cl-catalyzed O3 loss in the upper stratosphere. In addition, stratosphere-troposphere coupling strengthens the chemical feedback on its own lifetime. In the stratosphere, this feedback operates by a CH4 perturbation thickening the stratospheric O3 layer, which impedes UV-driven OH production in the troposphere and prolongs the CH4 lifetime. We also quantify the impact of CH4-derived H2O on the stratospheric HOx cycles but these effects are small. Combining all of the above, these models suggest that the 100-yr GWP of CH4 is over 33.5, a 20% increase over the latest IPCC assessment.

  15. Modulations of stratospheric ozone by volcanic eruptions

    Science.gov (United States)

    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.

  16. Easy Volcanic Aerosol (EVA v1.0: an idealized forcing generator for climate simulations

    Directory of Open Access Journals (Sweden)

    M. Toohey

    2016-11-01

    Full Text Available Stratospheric sulfate aerosols from volcanic eruptions have a significant impact on the Earth's climate. To include the effects of volcanic eruptions in climate model simulations, the Easy Volcanic Aerosol (EVA forcing generator provides stratospheric aerosol optical properties as a function of time, latitude, height, and wavelength for a given input list of volcanic eruption attributes. EVA is based on a parameterized three-box model of stratospheric transport and simple scaling relationships used to derive mid-visible (550 nm aerosol optical depth and aerosol effective radius from stratospheric sulfate mass. Precalculated look-up tables computed from Mie theory are used to produce wavelength-dependent aerosol extinction, single scattering albedo, and scattering asymmetry factor values. The structural form of EVA and the tuning of its parameters are chosen to produce best agreement with the satellite-based reconstruction of stratospheric aerosol properties following the 1991 Pinatubo eruption, and with prior millennial-timescale forcing reconstructions, including the 1815 eruption of Tambora. EVA can be used to produce volcanic forcing for climate models which is based on recent observations and physical understanding but internally self-consistent over any timescale of choice. In addition, EVA is constructed so as to allow for easy modification of different aspects of aerosol properties, in order to be used in model experiments to help advance understanding of what aspects of the volcanic aerosol are important for the climate system.

  17. Evidence for Dynamical Coupling of Stratosphere-MLT during recent minor Stratospheric Warmings in Southern Hemisphere

    Science.gov (United States)

    Kim, Yongha; Sunkara, Eswaraiah; Hong, Junseok; Ratnam, Venkat; Chandran, Amal; Rao, Svb; Riggin, Dennis

    2015-04-01

    The mesosphere-lower thermosphere (MLT) response to extremely rare minor sudden stratospheric warming (SSW) events was observed for the first time in the southern hemisphere (SH) during 2010 and is investigated using the meteor radar located at King Sejong Station (62.22°S, 58.78°W), Antarctica. Three episodic SSWs were noticed from early August to late October 2010. The mesospheric wind field was found to significantly differ from normal years due to enhanced planetary wave (PW) activity before the SSWs and secondary PWs in the MLT afterwards. The zonal winds in the mesosphere reversed approximately a week before the SSW occurrence in the stratosphere as has been observed 2002 major SSW, suggesting the downward propagation of disturbance during minor SSWs as well. Signatures of mesospheric cooling (MC) in association with SSWs are found in the Microwave Limb Sounder (MLS) measurements. SD-WACCM simulations are able to produce these observed features.

  18. Impacts of Stratospheric Sulfate Geoengineering on PM2.5

    Science.gov (United States)

    Robock, A.; Xia, L.; Tilmes, S.; Mills, M. J.; Richter, J.; Kravitz, B.; MacMartin, D.

    2017-12-01

    Particulate matter (PM) includes sulfate, nitrate, organic carbon, elemental carbon, soil dust, and sea salt. The first four components are mostly present near the ground as fine particulate matter with a diameter less than 2.5 µm (PM2.5), and these are of the most concern for human health. PM is efficiently scavenged by precipitation, which is its main atmospheric sink. Here we examine the impact of stratospheric climate engineering on this important pollutant and health risk, taking advantage of two sets of climate model simulations conducted at the National Center for Atmospheric Research. We use the full tropospheric and stratospheric chemistry version of the Community Earth System Model - Community Atmospheric Model 4 (CESM CAM4-chem) with a horizontal resolution of 0.9° x 1.25° lat-lon to simulate a stratospheric sulfate injection climate intervention of 8 Tg SO2 yr-1 combined with an RCP6.0 global warming forcing, the G4 Specified Stratospheric Aerosol (G4SSA) scenario. We also analyze the output from a 20-member ensemble of Community Earth System Model, version 1 with the Whole Atmosphere Community Climate Model as its atmospheric component (CESM1(WACCM)) simulations, also at 0.9° x 1.25° lat-lon resolution, with sulfur dioxide injection at 15°N, 15°S, 30°N, and 30°S varying in time to balance RCP8.5 forcing. While the CESM CAM4-chem model has full tropospheric and stratospheric chemistry, CESM1(WACCM) has an internally generated quasi-biennial oscillation and a comprehensive tropospheric and stratospheric sulfate aerosol treatment, but only stratospheric chemistry. For G4SSA, there are a global temperature reduction of 0.8 K and global averaged precipitation decrease of 3% relative to RCP6.0. The global averaged surface PM2.5 reduces about 1% compared with RCP6.0, mainly over Eurasian and East Asian regions in Northern Hemisphere winter. The PM2.5 concentration change is a combination of effects from tropospheric chemistry and precipitation

  19. Review of recent research on the climatic effect of aerosols

    International Nuclear Information System (INIS)

    Charlock, T.P.; Kondratyev, K.; Prokofyev, M.

    1993-01-01

    A review of relatively recent research on the climatic effects of aerosols is presented. Most of the inferences of the climatic effects of aerosols have been obtained through assuming a certain aerosol model in conjunction with a particular climate model. The following radiative effects of aerosols are identified: The planetary albedo is generally increased due to the backscatter of solar radiation by aerosols, with the exception of aerosols situated above a highly reflecting surface. Solar radiation absorption by some aerosols can offset the cooling due to aerosol backscatter. Although aerosol effects dominate for short-wave radiation, absorption and emission of terrestrial radiation by aerosols produces a warming effect. Various climate models are used to assess the impact of aerosols on climate. A two-stream approximation to the radiation transfer equation is adequate for optically thin layers where single scattering is applicable. Improved models to include aerosol terrestrial radiation effects, important feedback mechanisms, and the prediction of globally and seasonally averaged surface and atmospheric temperatures are provided by the so-called radiative-convective models (RCM's). The basic structure of the RCM's, which is regarded as adequate for many aerosol climate applications, is described. The general circulation model (GCM) is also described briefly. A full-scale GCM incorporating realistic aerosol inputs is yet to be formulated to include regional variability of the aerosol. Moreover, detailed computer modeling associated with GCM climate models can often confuse the basic physics. Because volcanic aerosols injected into the stratosphere have long residence times, they provide a good case study of the climate response to a change in the atmospheric aerosol. The chapter gives a critique of modeling work done to establish climatic effects of stratospheric aerosols

  20. Tropical stratospheric water vapor measured by the microwave limb sounder (MLS)

    Science.gov (United States)

    Carr, E. S.; Harwood, R. S.; Mote, P. W.; Peckham, G. E.; Suttie, R. A.; Lahoz, W. A.; O'Neill, A.; Froidevaux, L.; Jarnot, R. F.; Read, W. G.

    1995-01-01

    The lower stratospheric variability of equatorial water vapor, measured by the Microwave Limb Sounder (MLS), follows an annual cycle modulated by the quasi-biennial oscillation. At levels higher in the stratosphere, water vapor measurements exhibit a semi-annual oscillatory signal with the largest amplitudes at 2.2 and 1hPa. Zonal-mean cross sections of MLS water vapor are consistent with previous satellite measurements from the limb infrared monitor of the stratosphere (LIMS) and the stratospheric Aerosol and Gas Experiment 2 (SAGE 2) instruments in that they show water vapor increasing upwards and the polewards from a well defined minimum in the tropics. The minimum values vary in height between the retrieved 46 and 22hPa pressure levels.

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

    Energy Technology Data Exchange (ETDEWEB)

    Drdla, K. [NASA Ames Research Center, Moffett Field, CA (United States); Mueller, R. [Forschungszentrum Juelich (DE). Inst. of Energy and Climate Research (IEK-7)

    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 HNO{sub 3} from the gas phase. Using reaction rates on cold binary aerosol in a model of stratospheric chemistry, a chlorine activation threshold temperature, T{sub ACL}, is derived. At typical stratospheric conditions, T{sub ACL} is similar in value to T{sub NAT} (within 1-2 K), the highest temperature at which nitric acid trihydrate (NAT) can exist. T{sub NAT} is still in use to parameterise the threshold temperature for the onset of chlorine activation. However, perturbations can cause T{sub ACL} to differ from T{sub NAT}: T{sub ACL} is dependent upon H{sub 2} O and potential temperature, but unlike T{sub NAT} is not dependent upon HNO3. Furthermore, in contrast to T{sub NAT}, T{sub ACL} 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 T{sub ACL} 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 T{sub ACL} 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, T{sub ACL} provides a more accurate description of the temperature conditions necessary for chlorine activation and ozone loss in the polar stratosphere than T{sub NAT}. (orig.)

  2. El Chichon and 'mystery cloud' aerosols between 30 and 55 km Global observations from the SME visible spectrometer

    Science.gov (United States)

    Clancy, R. T.

    1986-01-01

    Visible limb radiances measured by the Solar Mesosphere Explorer (SME) are used to obtain volume scattering ratios for aerosol loading in the 30-55 km altitude range of the stratosphere. Global maps of these ratios are presented for the period January 1982 to August 1984. Significant aerosol scattering from the 'mystery cloud' and El Chichon aerosol layers are found above 30 km. A timescale of approximately 2 months between the appearance of the aerosol at 30.5 km and at 37.5 km is consistent with vertical transport of aerosol or vapor by eddy diffusion above 30 km. An anticorrelation exists between aerosol scattering and stratospheric temperatures. Periods of lower stratospheric temperatures may account for the formation of aerosol between 40 and 55 km altitude.

  3. Global volcanic aerosol properties derived from emissions, 1990-2014, using CESM1(WACCM): VOLCANIC AEROSOLS DERIVED FROM EMISSIONS

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Michael J. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Schmidt, Anja [School of Earth and Environment, University of Leeds, Leeds UK; Easter, Richard [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Solomon, Susan [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge Massachusetts USA; Kinnison, Douglas E. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Ghan, Steven J. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Neely, Ryan R. [School of Earth and Environment, University of Leeds, Leeds UK; National Centre for Atmospheric Science, University of Leeds, Leeds UK; Marsh, Daniel R. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Conley, Andrew [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Bardeen, Charles G. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Gettelman, Andrew [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA

    2016-03-06

    Accurate representation of global stratospheric aerosol properties from volcanic and non-volcanic sulfur emissions is key to understanding the cooling effects and ozone-loss enhancements of recent volcanic activity. Attribution of climate and ozone variability to volcanic activity is of particular interest in relation to the post-2000 slowing in the apparent rate of global average temperature increases, and variable recovery of the Antarctic ozone hole. We have developed a climatology of global aerosol properties from 1990 to 2014 calculated based on volcanic and non-volcanic emissions of sulfur sources. We have complied a database of volcanic SO2 emissions and plume altitudes for eruptions between 1990 and 2014, and a new prognostic capability for simulating stratospheric sulfate aerosols in version 5 of the Whole Atmosphere Community Climate Model, a component of the Community Earth System Model. Our climatology shows remarkable agreement with ground-based lidar observations of stratospheric aerosol optical depth (SAOD), and with in situ measurements of aerosol surface area density (SAD). These properties are key parameters in calculating the radiative and chemical effects of stratospheric aerosols. Our SAOD climatology represents a significant improvement over satellite-based analyses, which ignore aerosol extinction below 15 km, a region that can contain the vast majority of stratospheric aerosol extinction at mid- and high-latitudes. Our SAD climatology significantly improves on that provided for the Chemistry-Climate Model Initiative, which misses 60% of the SAD measured in situ. Our climatology of aerosol properties is publicly available on the Earth System Grid.

  4. El Nino, from 1870 to 2014, and other Atmospheric Circulation Forcing by Extreme Apparitions of the Eight Annual, Continental Scale, Aerosol Plumes in the Satellite Era which Point to a Possible Cause for the Current Californian Drought

    Science.gov (United States)

    Potts, K. A.

    2015-12-01

    Eight continental scale aerosol plumes exist each year as the enclosed image shows. Apparitions of seven plumes only exist for a few months in the same season each year whilst the East Asian Plume is visible all year. The aerosol optical depth (AOD) of all the plumes varies enormously interannually with two studies showing the surface radiative forcing of the South East Asian Plume (SEAP) as -150W/m2 and -286W/m2/AOD. I show that the SEAP, created by volcanic aerosols (natural) and biomass burning and gas flares in the oil industry (anthropogenic), is the sole cause of all El Nino events, the greatest interannual perturbation of the atmospheric circulation system. The SEAP creates an El Nino by absorbing solar radiation at the top of the plume which heats the upper atmosphere and cools the surface. This creates a temperature inversion compared to periods without the plume and reduces convection. With reduced convection in SE Asia, the Maritime Continent, the Trade Winds blowing across the Pacific are forced to relax as their exit into the Hadley and Walker Cells is constrained and the reduced Trade Wind speed causes the Sea Surface Temperature (SST) to rise in the central tropical Pacific Ocean as there is a strong negative correlation between wind speed and SST. The warmer SST in the central Pacific creates convection in the region which further reduces the Trade Wind speed and causes the Walker Cell to reverse - a classic El Nino. Having established the ability of such extreme aerosol plumes to create El Nino events I will then show how the South American, West African, Middle East and SEAP plumes create drought in the Amazon, Spain, Darfur and Australia as well as causing the extremely warm autumn and winter in Europe in 2006-07. All these effects are created by the plumes reducing convection in the region of the plume which forces the regional Hadley Cells into anomalous positions thereby creating persistent high pressure cells in the mid latitudes. This

  5. Stratospheric controlled perturbation experiment (SCoPEx): overview, status, and results from related laboratory experiments

    Science.gov (United States)

    Keith, D.; Dykema, J. A.; Keutsch, F. N.

    2017-12-01

    Stratospheric Controlled Perturbation Experiment (SCoPEx), is a scientific experiment to advance understanding of stratospheric aerosols. It aims to make quantitative measurements of aerosol microphysics and atmospheric chemistry to improve large-scale models used to assess the risks and benefits of solar geoengineering. A perturbative experiment requires: (a) means to create a well-mixed, small perturbed volume, and (b) observation of time evolution of chemistry and aerosols in the volume. SCoPEx will used a propelled balloon gondola containing all instruments and drive system. The propeller wake forms a well-mixed volume (roughly 1 km long and 100 meters in diameter) that serves as an experimental `beaker' into which aerosols (e.g., budget, etc; (d) results from CFD simulation of propeller wake and simulation of chemistry and aerosol microphysics; and finally (e) proposed concept of operations and schedule. We will also provide an overview of the plans for governance including management of health safety and environmental risks, transparency, public engagement, and larger questions about governance of solar geoengineering experiments. Finally, we will briefly present results of laboratory experiments of the interaction of chemical such as ClONO2 and HCl on particle surfaces relevant for stratospheric solar geoengineering.

  6. Impacts of stratospheric sulfate geoengineering on tropospheric ozone

    Science.gov (United States)

    Xia, Lili; Nowack, Peer J.; Tilmes, Simone; Robock, Alan

    2017-10-01

    A range of solar radiation management (SRM) techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air pollution. In conclusion

  7. Impacts of stratospheric sulfate geoengineering on tropospheric ozone

    Directory of Open Access Journals (Sweden)

    L. Xia

    2017-10-01

    Full Text Available A range of solar radiation management (SRM techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air

  8. Chapter 3: Evaluating the impacts of carbonaceous aerosols on clouds and climate

    Energy Technology Data Exchange (ETDEWEB)

    Menon, Surabi; Del Genio, Anthony D.

    2007-09-03

    other models as well (cf. Jacobson, 2002) but the relative impacts on convective and stratiform processes were not separated. Other changes to atmospheric stability and thermodynamical quantities due to aerosol absorption are also known to be important in modifying cloud macro/micro properties. Linkages between convection and boreal biomass burning can also impact the upper troposphere and lower stratosphere, radiation and cloud microphysical properties via transport of tropospheric aerosols to the lower stratosphere during extreme convection (Fromm and Servranckx 2003). Relevant questions regarding the impact of biomass aerosols on convective cloud properties include the effects of vertical transport of aerosols, spatial and temporal distribution of rainfall, vertical shift in latent heat release, phase shift of precipitation, circulation and their impacts on radiation. Over land surfaces, a decrease in surface shortwave radiation ({approx} 3-6 W m{sup -2} per decade) has been observed between 1960 to 1990, whereas, increases of 0.4 K in land temperature during the same period that occurred have resulted in speculations that evaporation and precipitation should also have decreased (Wild et al. 2004). However, precipitation records for the same period over land do not indicate any significant trend (Beck et al. 2005). The changes in precipitation are thought to be related to increased moisture advection from the oceans (Wild et al. 2004), which may well have some contributions from aerosol-radiation-convection coupling that could modify circulation patterns and hence moisture advection in specific regions. Other important aspects of aerosol effects, besides the direct, semi-direct, microphysical and thermodynamical impacts include alteration of surface albedos, especially snow and ice covered surfaces, due to absorbing aerosols. These effects are uncertain (Jacobson, 2004) but may produce as much as 0.3 W m{sup -2} forcing in the Northern hemisphere that could

  9. Elemental concentrations in tropospheric and lower stratospheric air in a Northeastern region of Poland

    Science.gov (United States)

    Braziewicz, Janusz; Kownacka, Ludwika; Majewska, Urszula; Korman, Andrzej

    Element concentrations of K, Ca, Ti, Cr, Fe, Ni, Cu, Zn, Se, Br, Sr and Pb as well as the activity of natural radionuclides 210Pb and 226Ra in air were measured. The aerosol samples were collected during tropospheric and stratospheric aircraft flights over the Northeastern region of Poland, which is mostly an agricultural and wooded area. The air volumes were filtered using Petrianov filters at 1, 3, 6, 9, 12 and 15 km above the ground level by special equipment attached to a jet plane. Aircraft flights were provided from September 1997 to August 1998 in 5 separate sampling runs. The long sampling distances served as a good representation of mean aerosol composition and distribution. Concentrations of the same elements were also measured using stationary equipment near the ground level at the outskirts of Warsaw. The vertical profiles of element concentration were obtained and the elemental compositions for the tropospheric and stratospheric aerosols were compared with those from the near-ground level. Contribution of K, Ca, Ti and Fe, which are the main components of soil, in total mass of all detected ones was estimated. Relative concentrations of all measured elements, which show any differences in the composition of the aerosol were calculated. The results obtained confirm the fact that the stratospheric reservoir is observed in the bottom stratosphere. The XRF method based on molybdenum X-ray tube was used as an analytical tool in the determination of aerosols trace elements. The altitude distributions of radioactivity of 226Ra and 210Pb were determined using radiochemical methods.

  10. Post-entry and volcanic contaminant abundances of zinc, copper, selenium, germanium and gallium in stratospheric micrometeorites

    Science.gov (United States)

    Rietmeijer, Frans J. M.

    1995-01-01

    Some fraction of Zn, Cu, Se, Ga and Ge in chondritic interplanetary dust particles (IDPs) collected in the lower stratosphere between 1981 May and 1984 June has a volcanic origin. I present a method to evaluate the extent of this unavoidable type of stratospheric contamination for individual particles. The mass-normalized abundances for Cu and Ge as a function of mass-normalized stratospheric residence time show their time-integrated stratospheric aerosol abundances. The Zn, Se and Ga abundances show a subdivision into two groups that span approximately two-year periods following the eruptions of the Mount St. Helens (1980 May) and El Chichon (1982 April) volcanoes. Elemental abundances in particles collected at the end of each two-year period indicate low, but not necessarily ambient, volcanic stratospheric abundances. Using this time-integrated baseline, I calculate the straospheric contaminant fractions in nine IDPs and show that Zn, SE and Ga abundances in chondritic IDPs derive in part from stratospheric aerosol contaminants. Post-entry elemental abundances (i.e., the amount that survived atmospheric entry heating of the IDP) show enrichments relative to the CI abundances but in a smaller number of particles than previously suggested.

  11. Aerosol Climate Time Series Evaluation In ESA Aerosol_cci

    Science.gov (United States)

    Popp, T.; de Leeuw, G.; Pinnock, S.

    2015-12-01

    Within the ESA Climate Change Initiative (CCI) Aerosol_cci (2010 - 2017) conducts intensive work to improve algorithms for the retrieval of aerosol information from European sensors. By the end of 2015 full mission time series of 2 GCOS-required aerosol parameters are completely validated and released: Aerosol Optical Depth (AOD) from dual view ATSR-2 / AATSR radiometers (3 algorithms, 1995 - 2012), and stratospheric extinction profiles from star occultation GOMOS spectrometer (2002 - 2012). Additionally, a 35-year multi-sensor time series of the qualitative Absorbing Aerosol Index (AAI) together with sensitivity information and an AAI model simulator is available. Complementary aerosol properties requested by GCOS are in a "round robin" phase, where various algorithms are inter-compared: fine mode AOD, mineral dust AOD (from the thermal IASI spectrometer), absorption information and aerosol layer height. As a quasi-reference for validation in few selected regions with sparse ground-based observations the multi-pixel GRASP algorithm for the POLDER instrument is used. Validation of first dataset versions (vs. AERONET, MAN) and inter-comparison to other satellite datasets (MODIS, MISR, SeaWIFS) proved the high quality of the available datasets comparable to other satellite retrievals and revealed needs for algorithm improvement (for example for higher AOD values) which were taken into account for a reprocessing. The datasets contain pixel level uncertainty estimates which are also validated. The paper will summarize and discuss the results of major reprocessing and validation conducted in 2015. The focus will be on the ATSR, GOMOS and IASI datasets. Pixel level uncertainties validation will be summarized and discussed including unknown components and their potential usefulness and limitations. Opportunities for time series extension with successor instruments of the Sentinel family will be described and the complementarity of the different satellite aerosol products

  12. Quantifying the risks of solid aerosol geoengineering: the role of fundamental material properties

    Science.gov (United States)

    Dykema, J. A.; Keutsch, F. N.; Keith, D.

    2017-12-01

    Solid aerosols have been considered as an alternative to sulfate aerosols for solar geoengineering due to their optical and chemical properties, which lead to different and possibly more attractive risk profiles. Solid aerosols can achieve higher solar scattering efficiency due to their higher refractive index, and in some cases may also be less effective absorbers of thermal infrared radiation. The optical properties of solid aerosols are however sensitive functions of the detailed physical properties of solid materials in question. The relevant details include the exact crystalline structure of the aerosols, the physical size of the particles, and interactions with background stratospheric molecular and particulate constituents. In this work, we examine the impact of these detailed physical properties on the radiative properties of calcite (CaCO3) solid aerosols. We examine how crystal morphology, size, chemical reactions, and interaction with background stratospheric aerosol may alter the scattering and absorption properties of calcite aerosols for solar and thermal infrared radiation. For example, in small particles, crystal lattice vibrations associated with the particle surface may lead to substantially different infrared absorption properties than bulk materials. We examine the wavelength dependence of absorption by the particles, which may lead to altered patterns of stratospheric radiative heating and equilibrium temperatures. Such temperature changes can lead to dynamical changes, with consequences for both stratospheric composition and tropospheric climate. We identify important uncertainties in the current state of understanding, investigate risks associated with these uncertainties, and survey potential approaches to quantitatively improving our knowledge of the relevant material properties.

  13. Organic aerosols

    International Nuclear Information System (INIS)

    Penner, J.E.

    1994-01-01

    Organic aerosols scatter solar radiation. They may also either enhance or decrease concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the sources of organic aerosol matter. The anthropogenic sources of organic aerosols may be as large as the anthropogenic sources of sulfate aerosols, implying a similar magnitude of direct forcing of climate. The source estimates are highly uncertain and subject to revision in the future. A slow secondary source of organic aerosols of unknown origin may contribute to the observed oceanic concentrations. The role of organic aerosols acting as cloud condensation nuclei (CCN) is described and it is concluded that they may either enhance or decrease the ability of anthropogenic sulfate aerosols to act as CCN

  14. Lower stratospheric observations from aircraft and satellite during the 2015/2016 El Nino

    Science.gov (United States)

    Rosenlof, K. H.; Avery, M. A.; Davis, S. M.; Gao, R. S.; Thornberry, T. D.

    2016-12-01

    Winter 2015/2016 experienced a strong El Nino that was heavily observed by aircraft, radiosonde and satellite platforms. During the National Oceanographic and Atmospheric Administration's (NOAA) Sensing Hazards with Operational Unmanned Technology (SHOUT)/El Nino Rapid Response (ENRR) flights of the NASA Global Hawk, in situ ozone measurements were made in the lower stratosphere over the Pacific. These will be contrasted with ozone measurements taken during La Nina and ENSO neutral conditions during past Global Hawk aircraft campaigns. Additionally, lower stratospheric water vapor and ozone measurements from the Microwave Limb Sounder satellite instrument and stratospheric ice measurements above the tropopause from the Cloud-Aerosol Aerosol Lidar with Orthogonal Polarization (CALIOP) will be presented. Our aircraft ozone measurements are higher for the El Nino flights than during other missions previously sampled, while zonally averaged lower stratospheric water vapor and central Pacific ice path above the tropopause reached record highs. Implications and possible reasons for these anomalous observations will be discussed. Winter 2015/2016 experienced a strong El Nino that was heavily observed by aircraft, radiosonde and satellite platforms. During the National Oceanographic and Atmospheric Administration's (NOAA) Sensing Hazards with Operational Unmanned Technology (SHOUT)/El Nino Rapid Response (ENRR) flights of the NASA Global Hawk, in situ ozone measurements were made in the upper troposphere and lower stratosphere (UTLS) over the Pacific. These will be contrasted with ozone measurements made during La Nina and ENSO neutral conditions during past Global Hawk aircraft campaigns. Additionally, UTLS water vapor and ozone measurements from the Microwave Limb Sounder (MLS) satellite instrument and stratospheric ice measurements above the tropopause from the Cloud-Aerosol Aerosol Lidar with Orthogonal Polarization (CALIOP) will be presented. Our aircraft ozone

  15. Radioactive aerosols

    International Nuclear Information System (INIS)

    Chamberlain, A.C.

    1991-01-01

    Radon. Fission product aerosols. Radioiodine. Tritium. Plutonium. Mass transfer of radioactive vapours and aerosols. Studies with radioactive particles and human subjects. Index. This paper explores the environmental and health aspects of radioactive aerosols. Covers radioactive nuclides of potential concern to public health and applications to the study of boundary layer transport. Contains bibliographic references. Suitable for environmental chemistry collections in academic and research libraries

  16. Comparison of aerosol extinction between lidar and SAGE II over Gadanki, a tropical station in India

    Directory of Open Access Journals (Sweden)

    P. Kulkarni

    2015-03-01

    Full Text Available An extensive comparison of aerosol extinction has been performed using lidar and Stratospheric Aerosol and Gas Experiment (SAGE II data over Gadanki (13.5° N, 79.2° E, a tropical station in India, following coincident criteria during volcanically quiescent conditions from 1998 to 2005. The aerosol extinctions derived from lidar are higher than SAGE II during all seasons in the upper troposphere (UT, while in the lower-stratosphere (LS values are closer. The seasonal mean percent differences between lidar and SAGE II aerosol extinctions are > 100% in the UT and Ba (sr−1, the ratio between aerosol backscattering and extinction, are needed for the tropics for a more accurate derivation of aerosol extinction.

  17. Detection and mapping of polar stratospheric clouds using limb scattering observations

    Directory of Open Access Journals (Sweden)

    C. von Savigny

    2005-01-01

    Full Text Available Satellite-based measurements of Visible/NIR limb-scattered solar radiation are well suited for the detection and mapping of polar stratospheric clouds (PSCs. This publication describes a method to detect PCSs from limb scattering observations with the Scanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY on the European Space Agency's Envisat spacecraft. The method is based on a color-index approach and requires a priori knowledge of the stratospheric background aerosol loading in order to avoid false PSC identifications by stratospheric background aerosol. The method is applied to a sample data set including the 2003 PSC season in the Southern Hemisphere. The PSCs are correlated with coincident UKMO model temperature data, and with very few exceptions, the detected PSCs occur at temperatures below 195–198 K. Monthly averaged PSC descent rates are about 1.5 km/month for the −50° S to −75° S latitude range and assume a maximum between August and September with a value of about 2.5 km/month. The main cause of the PSC descent is the slow descent of the lower stratospheric temperature minimum.

  18. Balance of the tropospheric ozone and its relation to stratospheric intrusions indicated by cosmogenic radionuclides. Part 13. Annual report, 1 February 1982-31 January 1983

    International Nuclear Information System (INIS)

    Reiter, R.; Kanter, H.J.; Jaeger, H.; Munzert, K.

    1985-06-01

    A statistical evaluation of tropospheric ozone concentrations in the air obtained at 3 different levels is presented from data covering 1977 to 1984. Annual and interannual variations are used to project a trend. To clarify the climatology of the stratospheric exchange, the measuring series of cosmogenic radionuclides Be7, P32, P33 covering the period 1970 through 1981 are statistically analyzed with regard to the ozone concentration recorded on the Zugspitze. The statistics of stratospheric intrusions is shown and the stratospheric residence time is estimated. Effects of the eruption of volcano El Chichon in April 1982 on the concentration of the stratospheric aerosol are documented. The time variation of the concentration of the stratospheric aerosol is studied with consideration of the stratospheric circulation. The noted effects are weighed by a comparison with earlier volcanic eruptions. First results of CO 2 recordings in the lower stratosphere are presented. Based on CO 2 recording series from two different levels (740 m and 1780 m a.s.1) from the years 1978 to 1980, systematic differences are shown as a function of height. The question of sources and sinks is discussed to assess the contribution from anthropogenic sources

  19. Observations of reduced ozone concentrations in the tropical stratosphere after the eruption of Mt. Pinatubo

    Science.gov (United States)

    Grant, W. B.; Fishman, J.; Browell, E. V.; Brackett, V. G.; Nganga, D.; Minga, A.; Cros, B.; Veiga, R. E.; Butler, C. F.; Fenn, M. A.

    1992-01-01

    Two independent sets of data, one of aerosols from an airborne lidar system, and one of ozone from ozonesonde measurements indicate that significant ozone decreases may have happened as a result of the injection of debris by the Mt. Pinatubo volcano in June 1991. The amount of this reduction maximizes at 24-25 km, near the peak of the aerosol distribution, though a deficit is seen throughout the lower stratosphere between 19 and 28 km. The greatest differences observed prior and subsequent to the eruptions at these altitudes is 18-20 percent.

  20. Observations of the loss of stratospheric NO2 following volcanic eruptions

    Science.gov (United States)

    Coffey, M. T.; Mankin, William G.

    1993-01-01

    Observations of stratospheric column amounts of nitrogen dioxide (NO2), nitric oxide (NO) and nitric acid (HNO3) have been made following major eruptions of the El Chichon and Mt. Pintatubo volcanoes. Midlatitude abundances of NO2 and NO were reduced by as much as 70% in the months following the appearance of the volcanic aerosols as compared to volcanically quite periods. There are heterogeneous reactions which could occur on the volcanic aerosols to convert NO2 into HNO3 but no commensurate increase in HNO3 column amounts was observed at the times of NO2 decrease.

  1. Drift-corrected Odin-OSIRIS ozone product: algorithm and updated stratospheric ozone trends

    Directory of Open Access Journals (Sweden)

    A. E. Bourassa

    2018-01-01

    Full Text Available A small long-term drift in the Optical Spectrograph and Infrared Imager System (OSIRIS stratospheric ozone product, manifested mostly since 2012, is quantified and attributed to a changing bias in the limb pointing knowledge of the instrument. A correction to this pointing drift using a predictable shape in the measured limb radiance profile is implemented and applied within the OSIRIS retrieval algorithm. This new data product, version 5.10, displays substantially better both long- and short-term agreement with Microwave Limb Sounder (MLS ozone throughout the stratosphere due to the pointing correction. Previously reported stratospheric ozone trends over the time period 1984–2013, which were derived by merging the altitude–number density ozone profile measurements from the Stratospheric Aerosol and Gas Experiment (SAGE II satellite instrument (1984–2005 and from OSIRIS (2002–2013, are recalculated using the new OSIRIS version 5.10 product and extended to 2017. These results still show statistically significant positive trends throughout the upper stratosphere since 1997, but at weaker levels that are more closely in line with estimates from other data records.

  2. Stratospheric sulfuric acid fraction and mass estimate for the 1982 volcanic eruption of El Chichon

    Science.gov (United States)

    Hofmann, D. J.; Rosen, J. M.

    1983-01-01

    The stratospheric sulfuric acid fraction and mass for the 1982 volcanic eruptions of El Chichon are investigated using data from balloon soundings at Laramie (41 deg N) and in southern Texas (27-29 deg N). The total stratospheric mass of these eruptions is estimated to be approximately 8 Tg about 6.5 months after the eruption with possibly as much as 20 Tg in the stratosphere about 45 days after the eruption. Observations of the aerosol in Texas revealed two primary layers, both highly volatile at 150 C. Aerosol in the upper layer at about 25 km was composed of an approximately 80 percent H2SO4 solution while the lower layer at approximately 18 km was composed of a 60-65 percent H2SO4 solution aerosol. It is calculated that an H2SO4 vapor concentration of at least 3 x 10 to the 7th molecules/cu cm is needed to sustain the large droplets in the upper layer. An early bi-modal nature in the size distribution indicates droplet nucleation from the gas phase during the first 3 months, while the similarity of the large particle profiles 2 months apart shows continued particle growth 6.5 months after the explosion.

  3. On the detection of the solar signal in the tropical stratosphere

    Directory of Open Access Journals (Sweden)

    G. Chiodo

    2014-06-01

    Full Text Available We investigate the relative role of volcanic eruptions, El Niño–Southern Oscillation (ENSO, and the quasi-biennial oscillation (QBO in the quasi-decadal signal in the tropical stratosphere with regard to temperature and ozone commonly attributed to the 11 \\unit{yr} solar cycle. For this purpose, we perform transient simulations with the Whole Atmosphere Community Climate Model forced from 1960 to 2004 with an 11 yr solar cycle in irradiance and different combinations of other forcings. An improved multiple linear regression technique is used to diagnose the 11 yr solar signal in the simulations. One set of simulations includes all observed forcings, and is thereby aimed at closely reproducing observations. Three idealized sets exclude ENSO variability, volcanic aerosol forcing, and QBO in tropical stratospheric winds, respectively. Differences in the derived solar response in the tropical stratosphere in the four sets quantify the impact of ENSO, volcanic events and the QBO in attributing quasi-decadal changes to the solar cycle in the model simulations. The novel regression approach shows that most of the apparent solar-induced lower-stratospheric temperature and ozone increase diagnosed in the simulations with all observed forcings is due to two major volcanic eruptions (i.e., El Chichón in 1982 and Mt. Pinatubo in 1991. This is caused by the alignment of these eruptions with periods of high solar activity. While it is feasible to detect a robust solar signal in the middle and upper tropical stratosphere, this is not the case in the tropical lower stratosphere, at least in a 45 yr simulation. The present results suggest that in the tropical lower stratosphere, the portion of decadal variability that can be unambiguously linked to the solar cycle may be smaller than previously thought.

  4. On the aliasing of the solar cycle in the lower stratospheric tropical temperature

    Science.gov (United States)

    Kuchar, Ales; Ball, William T.; Rozanov, Eugene V.; Stenke, Andrea; Revell, Laura; Miksovsky, Jiri; Pisoft, Petr; Peter, Thomas

    2017-09-01

    The double-peaked response of the tropical stratospheric temperature profile to the 11 year solar cycle (SC) has been well documented. However, there are concerns about the origin of the lower peak due to potential aliasing with volcanic eruptions or the El Niño-Southern Oscillation (ENSO) detected using multiple linear regression analysis. We confirm the aliasing using the results of the chemistry-climate model (CCM) SOCOLv3 obtained in the framework of the International Global Atmospheric Chemisty/Stratosphere-troposphere Processes And their Role in Climate Chemistry-Climate Model Initiative phase 1. We further show that even without major volcanic eruptions included in transient simulations, the lower stratospheric response exhibits a residual peak when historical sea surface temperatures (SSTs)/sea ice coverage (SIC) are used. Only the use of climatological SSTs/SICs in addition to background stratospheric aerosols removes volcanic and ENSO signals and results in an almost complete disappearance of the modeled solar signal in the lower stratospheric temperature. We demonstrate that the choice of temporal subperiod considered for the regression analysis has a large impact on the estimated profile signal in the lower stratosphere: at least 45 consecutive years are needed to avoid the large aliasing effect of SC maxima with volcanic eruptions in 1982 and 1991 in historical simulations, reanalyses, and observations. The application of volcanic forcing compiled for phase 6 of the Coupled Model Intercomparison Project (CMIP6) in the CCM SOCOLv3 reduces the warming overestimation in the tropical lower stratosphere and the volcanic aliasing of the temperature response to the SC, although it does not eliminate it completely.

  5. Impacts of Stratospheric Black Carbon on Agriculture

    Science.gov (United States)

    Xia, L.; Robock, A.; Elliott, J. W.

    2017-12-01

    impacts. We present these results as a demonstration of using different crop models to study this problem, and we invite more global crop modeling groups to use the same climate forcing, which we would be happy to provide, to gain a better understanding of global agricultural responses under different future climate scenarios with stratospheric aerosols.

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

    Science.gov (United States)

    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

  7. Particulate sulfur in the upper troposphere and lowermost stratosphere – sources and climate forcing

    Directory of Open Access Journals (Sweden)

    B. G. Martinsson

    2017-09-01

    Full Text Available This study is based on fine-mode aerosol samples collected in the upper troposphere (UT and the lowermost stratosphere (LMS of the Northern Hemisphere extratropics during monthly intercontinental flights at 8.8–12 km altitude of the IAGOS-CARIBIC platform in the time period 1999–2014. The samples were analyzed for a large number of chemical elements using the accelerator-based methods PIXE (particle-induced X-ray emission and PESA (particle elastic scattering analysis. Here the particulate sulfur concentrations, obtained by PIXE analysis, are investigated. In addition, the satellite-borne lidar aboard CALIPSO is used to study the stratospheric aerosol load. A steep gradient in particulate sulfur concentration extends several kilometers into the LMS, as a result of increasing dilution towards the tropopause of stratospheric, particulate sulfur-rich air. The stratospheric air is diluted with tropospheric air, forming the extratropical transition layer (ExTL. Observed concentrations are related to the distance to the dynamical tropopause. A linear regression methodology handled seasonal variation and impact from volcanism. This was used to convert each data point into stand-alone estimates of a concentration profile and column concentration of particulate sulfur in a 3 km altitude band above the tropopause. We find distinct responses to volcanic eruptions, and that this layer in the LMS has a significant contribution to the stratospheric aerosol optical depth and thus to its radiative forcing. Further, the origin of UT particulate sulfur shows strong seasonal variation. We find that tropospheric sources dominate during the fall as a result of downward transport of the Asian tropopause aerosol layer (ATAL formed in the Asian monsoon, whereas transport down from the Junge layer is the main source of UT particulate sulfur in the first half of the year. In this latter part of the year, the stratosphere is the clearly dominating source of

  8. Effects of Volcanic Eruptions on Stratospheric Ozone Recovery

    Science.gov (United States)

    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.

  9. Negative chlorine ion chemistry in the upper stratosphere and its application to an artificially created dense electron cloud

    Directory of Open Access Journals (Sweden)

    S. S. Prasad

    >, instead of reacting with O. It must be emphasized that the present study is speculative at this time, because none of the relevant reactions have been investigated in the laboratory as yet. Nevertheless, it is very safe to say that the scheme of ozone preservation by electron scavenging of the upper stratospheric Cl is much less certain than implied in the studies reported by its original proponents, because those studies neglected the photodetachment from Cl- and made the highly unlikely assumption that the Cl-·H2O anion neither photodissociates nor reacts any further. The situation at the lower altitudes could be even more complex due to the formation of large cluster ions and the ion-induced aerosol formation. The lower atmospheric situation, therefore, requires much more study. The uncertainties in the scavenging scheme due to the electrostatic repulsion in the cloud should also be addressed. Despite the uncertainties about its environmental engineering usefulness, the emerging technology for artificial creation of plasmas, with any desired density and charge in the stratosphere, could have significant pure scientific values in the studies of stratospheric ion chemistry and ion-induced aerosol formation. Such studies have perennially suffered from the extremely low densities of the naturally occurring plasma.

  10. Negative chlorine ion chemistry in the upper stratosphere and its application to an artificially created dense electron cloud

    Directory of Open Access Journals (Sweden)

    S. S. Prasad

    1995-03-01

    much less certain than implied in the studies reported by its original proponents, because those studies neglected the photodetachment from Cl- and made the highly unlikely assumption that the Cl-·H2O anion neither photodissociates nor reacts any further. The situation at the lower altitudes could be even more complex due to the formation of large cluster ions and the ion-induced aerosol formation. The lower atmospheric situation, therefore, requires much more study. The uncertainties in the scavenging scheme due to the electrostatic repulsion in the cloud should also be addressed. Despite the uncertainties about its environmental engineering usefulness, the emerging technology for artificial creation of plasmas, with any desired density and charge in the stratosphere, could have significant pure scientific values in the studies of stratospheric ion chemistry and ion-induced aerosol formation. Such studies have perennially suffered from the extremely low densities of the naturally occurring plasma.

  11. Survival of Halophilic Archaea in the Stratosphere as a Mars Analog: A Transcriptomic Approach

    Science.gov (United States)

    DasSarma, S.; DasSarma, P.; Laye, V.; Harvey, J.; Reid, C.; Shultz, J.; Yarborough, A.; Lamb, A.; Koske-Phillips, A.; Herbst, A.; Molina, F.; Grah, O.; Phillips, T.

    2016-05-01

    On Earth, halophilic Archaea tolerate multiple extreme conditions similar to those on Mars. In order to study their survival, we launched live cultures into Earth’s stratosphere on helium balloons. The effects on survival and transcriptomes were interrogated in the lab.

  12. How does Interactive Chemistry Influence the Representation of Stratosphere-Troposphere Coupling in a Climate Model?

    Science.gov (United States)

    Haase, S.; Matthes, K. B.

    2017-12-01

    Changes in stratospheric ozone can trigger tropospheric circulation changes. In the Southern hemisphere (SH), the observed shift of the Southern Annular Mode was attributed to the observed trend in lower stratospheric ozone. In the Northern Hemisphere (NH), a recent study showed that extremely low stratospheric ozone conditions during spring produce robust anomalies in the troposphere (zonal wind, temperature and precipitation). This could only be reproduced in a coupled chemistry climate model indicating that chemical-dynamical feedbacks are also important on the NH. To further investigate the importance of interactive chemistry for surface climate, we conducted a set of experiments using NCAR's Community Earth System Model (CESM1) with the Whole Atmosphere Community Climate Model (WACCM) as the atmosphere component. WACCM contains a fully interactive stratospheric chemistry module in its standard configuration. It also allows for an alternative configuration, referred to as SC-WACCM, in which the chemistry (O3, NO, O, O2, CO2 and chemical and shortwave heating rates) is specified as a 2D field in the radiation code. A comparison of the interactive vs. the specified chemistry version enables us to evaluate the relative importance of interactive chemistry by systematically inhibiting the feedbacks between chemistry and dynamics. To diminish the effect of temporal interpolation when prescribing ozone, we use daily resolved zonal mean ozone fields for the specified chemistry run. Here, we investigate the differences in stratosphere-troposphere coupling between the interactive and specified chemistry simulations for the mainly chemically driven SH as well as for the mainly dynamically driven NH. We will especially consider years that are characterized by extremely low stratospheric ozone on the one hand and by large dynamical disturbances, i.e. Sudden Stratospheric Warmings, on the other hand.

  13. Climate change projections and stratosphere-troposphere interaction

    Energy Technology Data Exchange (ETDEWEB)

    Scaife, Adam A.; Fereday, David R.; Butchart, Neal; Hardiman, Steven C. [Met Office Hadley Centre, Exeter (United Kingdom); Spangehl, Thomas; Cubasch, Ulrich; Langematz, Ulrike [Freie Universitaet Berlin, Berlin (Germany); Akiyoshi, Hideharu [National Institute for Environmental Studies, Tsukuba (Japan); Bekki, Slimane [LATMOS-IPSL, UVSQ, UPMC, CNRS/INSU, Paris (France); Braesicke, Peter [University of Cambridge, Cambridge (United Kingdom); Chipperfield, Martyn P. [University of Leeds, School of Earth and Environment, Leeds (United Kingdom); Gettelman, Andrew [National Center for Atmospheric Research, Boulder, CO (United States); Michou, Martine [GAME/CNRM (Meteo France, CNRS), Toulouse (France); Rozanov, Eugene [PMOD/WRC and ETHZ, Davos (Switzerland); Shepherd, Theodore G. [University of Toronto, Toronto, ON (Canada)

    2012-05-15

    Climate change is expected to increase winter rainfall and flooding in many extratropical regions as evaporation and precipitation rates increase, storms become more intense and storm tracks move polewards. Here, we show how changes in stratospheric circulation could play a significant role in future climate change in the extratropics through an additional shift in the tropospheric circulation. This shift in the circulation alters climate change in regional winter rainfall by an amount large enough to significantly alter regional climate change projections. The changes are consistent with changes in stratospheric winds inducing a change in the baroclinic eddy growth rate across the depth of the troposphere. A change in mean wind structure and an equatorward shift of the tropospheric storm tracks relative to models with poor stratospheric resolution allows coupling with surface climate. Using the Atlantic storm track as an example, we show how this can double the predicted increase in extreme winter rainfall over Western and Central Europe compared to other current climate projections. (orig.)

  14. Effects of the Mt. Pinatubo eruption on the chemistry, radiative, and transport processes in the stratosphere

    International Nuclear Information System (INIS)

    Wuebbles, D.J.; Kinnison, D.E.; Grant, K.E.; Connell, P.S.

    1992-09-01

    Volcanic eruptions can significantly impact trace gas distribution in the upper troposphere and lower stratosphere. Massive eruptions, produce large quantities of SO 2 , H 2 O, chlorine compounds, and particulates. Modeling the effects of these impulsive increases in traces gases and comparing the results with observations from ground and satellite measurements provide unique opportunities to test current multi-dimensional chemical-radiative-transport models of the global atmosphere. Since these models are currently being used in assessment studies for future anthropogenic emissions of trace gases quantitative understanding of the accuracy of these models is essential. In this study, we have used observed data from the Stratospheric Aerosol and Gas Experiment II (SAGE II) aboard the Earth Radiation Budget Satellite (ERBS) to realistically represent both the time dependent change in aerosol surface area density and wavelength dependent extinction values from the Mt. Pinatubo Eruption. Increases in the aerosol loading increase the rate of important heterogeneous chemical reactions converting odd nitrogen in both ClONO 2 and N 2 O 5 to HNO 3 . Radiative effects of increases aerosol optical thickness include changes to net radiative heating rates and to actinic fluxes. Changes to heating rates will indirectly change chemical reaction rates via changes in atmospheric temperatures. changes in actinic fluxes will directly modify photodissociation rates

  15. Aerosol studies

    International Nuclear Information System (INIS)

    Cristy, G.A.; Fish, M.E.

    1978-01-01

    As part of the continuing studies of the effects of very severe reactor accidents, an effort was made to develop, test, and improve simple, effective, and inexpensive methods by which the average citizen, using only materials readily available, could protect his residence, himself, and his family from injury by toxic aerosols. The methods for protection against radioactive aerosols should be equally effective against a clandestine biological attack by terrorists. The results of the tests to date are limited to showing that spores of the harmless bacterium, bacillus globegii (BG), can be used as a simulant for the radioactive aerosols. An aerosol generator of Lauterbach type was developed which will produce an essentially monodisperse aerosol at the rate of 10 9 spores/min. Analytical techniques have been established which give reproducible results. Preliminary field tests have been conducted to check out the components of the system. Preliminary tests of protective devices, such as ordinary vacuum sweepers, have given protection factors of over 1000

  16. Detection of polar stratospheric clouds with ERS2/GOME data

    International Nuclear Information System (INIS)

    Meerkoetter, R.; Schumann, U.

    1994-01-01

    Based on radiative transfer calculations it is studied whether Polar Stratospheric Clouds (PSCs) can be detected by the new Global Ozone Monitoring Experiment (GOME) onboard the second European Research Satellite (ERS-2) planned to be launched in winter 1994/95. It is proposed to identify PSC covered areas by use of an indicator, the Normalized Radiance Difference (NRD), which relates the difference of two spectral radiances at 0.5 μm and 0.7 μm to one radiance measured in the center of the oxygen A-band at 0.76 μm. The presence of PSCs and under conditions of large solar zenith angles Θ>80 the NRD values are clearly below those derived under conditions of a cloud free stratosphere. In this case the method is successful for PSCs with optical depths greater than 0.03 at 0.55 μm. It is not affected by existing tropospheric clouds and by different tropospheric aerosol loadings or surface albedoes. For solar zenith angles Θ<80 PSCs located above a cloud free troposphere are detectable. PSC detection becomes difficult for Θ<80 when highly reflecting tropospheric clouds like dense cirrus or stratus clouds affect spectral radiances measured at the top of the atmosphere. (orig.)

  17. On the cryogenic removal of NOy from the Antarctic polar stratosphere

    Directory of Open Access Journals (Sweden)

    S. Smyshlyaev

    2003-06-01

    Full Text Available We review current knowledge about the annual cycle of transport of nitrogen oxides to, and removal from, the polar stratosphere, with particular attention to Antarctica where the annual winter denitrifi cation process is both regular in occurrence and severe in effect. Evidence for a large downward fl ux of NOy from the mesosphere to the stratosphere, fi rst seen briefl y in the Limb Infrared Monitor of the Stratosphere (LIMS data from the Arctic winter of 1978-1979, has been found during the 1990s in both satellite and ground-based observations, though this still seems to be omitted from many atmospheric models. When incorporated in the Stony Brook- St. Petersburg two dimensional (2D transport and chemistry model, more realistic treatment of the NOy fl ux, along with sulfate transport from the mesosphere, sulfate aerosol formation where temperature is favorable, and the inclusion of a simple ion-cluster reaction, leads to good agreement with observed HNO3 formation in the mid-winter middle to upper stratosphere. To further emphasize the importance of large fl uxes of thermospheric and mesospheric NOy into the polar stratosphere, we have used observations, supplemented with model calculations, to defi ne new altitude dependent correlation curves between N2O and NOy. These are more suitable than those previously used in the literature to represent conditions within the Antarctic vortex region prior to and during denitrifi cation by Polar Stratospheric Cloud (PSC particles. Our NOy -N2O curves lead to a 40% increase in the average amount of NOy removed during the Antarctic winter with respect to estimates calculated using NOy-N2O curves from the Atmospheric Trace Molecule Spectroscopy (ATMOS/ATLAS-3 data set.

  18. Stratospheric HTO perturbations 1980-1983

    Science.gov (United States)

    Mason, A. S.

    1985-02-01

    Three perturbations of the stratospheric tritiated water burden have occurred. An atmospheric nuclear detonation in 1980 injected about 2.1 MCi. The massive eruptions of the volcano El Chichon may have contributed to a doubling of the removal rate in 1982. An unusually large wintertime exchange with the upper stratosphere may have occurred between 1982 and 1983.

  19. What Controls the Arctic Lower Stratosphere Temperature?

    Science.gov (United States)

    Newman, Paul A.; Nash, Eric R.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The temperature of the Arctic lower stratosphere is critical for understanding polar ozone levels. As temperatures drop below about 195 K, polar stratospheric clouds form, which then convert HCl and ClONO2 into reactive forms that are catalysts for ozone loss reactions. Hence, the lower stratospheric temperature during the March period is a key parameter for understanding polar ozone losses. The temperature is basically understood to be a result of planetary waves which drive the polar temperature away from a cold "radiative equilibrium" state. This is demonstrated using NCEP/NCAR reanalysis calculations of the heat flux and the mean polar temperature. The temperature during the March period is fundamentally driven by the integrated impact of large scale waves moving from the troposphere to the stratosphere during the January through February period. We will further show that the recent cold years in the northern polar vortex are a result of this weakened wave driving of the stratosphere.

  20. Aerosol Climate Time Series in ESA Aerosol_cci

    Science.gov (United States)

    Popp, Thomas; de Leeuw, Gerrit; Pinnock, Simon

    2016-04-01

    Within the ESA Climate Change Initiative (CCI) Aerosol_cci (2010 - 2017) conducts intensive work to improve algorithms for the retrieval of aerosol information from European sensors. Meanwhile, full mission time series of 2 GCOS-required aerosol parameters are completely validated and released: Aerosol Optical Depth (AOD) from dual view ATSR-2 / AATSR radiometers (3 algorithms, 1995 - 2012), and stratospheric extinction profiles from star occultation GOMOS spectrometer (2002 - 2012). Additionally, a 35-year multi-sensor time series of the qualitative Absorbing Aerosol Index (AAI) together with sensitivity information and an AAI model simulator is available. Complementary aerosol properties requested by GCOS are in a "round robin" phase, where various algorithms are inter-compared: fine mode AOD, mineral dust AOD (from the thermal IASI spectrometer, but also from ATSR instruments and the POLDER sensor), absorption information and aerosol layer height. As a quasi-reference for validation in few selected regions with sparse ground-based observations the multi-pixel GRASP algorithm for the POLDER instrument is used. Validation of first dataset versions (vs. AERONET, MAN) and inter-comparison to other satellite datasets (MODIS, MISR, SeaWIFS) proved the high quality of the available datasets comparable to other satellite retrievals and revealed needs for algorithm improvement (for example for higher AOD values) which were taken into account for a reprocessing. The datasets contain pixel level uncertainty estimates which were also validated and improved in the reprocessing. For the three ATSR algorithms the use of an ensemble method was tested. The paper will summarize and discuss the status of dataset reprocessing and validation. The focus will be on the ATSR, GOMOS and IASI datasets. Pixel level uncertainties validation will be summarized and discussed including unknown components and their potential usefulness and limitations. Opportunities for time series extension

  1. In situ trace gas and particle measurements in the summer lower stratosphere during STREAM II. Implications for O{sub 3} production

    Energy Technology Data Exchange (ETDEWEB)

    Bregman, A; Lelieveld, J; Scheeren, H A [Institute for Marine and Atmospheric Sciences, Utrecht (Netherlands); Arnold, F; Buerger, V; Schneider, J [Max-Planck-Inst. for Nuclear Physics, Heidelberg (Germany); Fischer, H; Waibel, A [Max-Planck-Inst. fuer Chemie, Mainz (Germany); Siegmund, P C; Wauben, W M.F. [Koninklijk Nederlands Meteorologisch Inst., De Bilt (Netherlands); Stroem, J [Stockholm Univ. (Sweden). Dept. of Meteorology

    1998-12-31

    In situ aircraft measurements of O{sub 3}, CO, HNO{sub 3}, and aerosol particles are presented, performed over the North Sea region in the summer lower stratosphere during the STREAM-II campaign (Stratosphere Troposphere Experiments by Aircraft Measurements). Elevated CO mixing ratios are attributed to mixing of polluted tropospheric air into the lowermost extra-tropical stratosphere. Model calculations illustrate that the O{sub 3} production efficiency of NO{sub x} is smaller than previously assumed, under conditions with relatively high HNO{sub 3} mixing ratios, as observed during STREAM-II. The model simulations further suggest a relatively high O{sub 3} production efficiency from CO oxidation, as a result of the relatively high ambient HNO{sub 3} and NO{sub x} concentrations, implying that upward transport of CO rich air enhances O{sub 3} production in the lowermost stratosphere. (author) 13 refs.

  2. In situ trace gas and particle measurements in the summer lower stratosphere during STREAM II. Implications for O{sub 3} production

    Energy Technology Data Exchange (ETDEWEB)

    Bregman, A.; Lelieveld, J.; Scheeren, H.A. [Institute for Marine and Atmospheric Sciences, Utrecht (Netherlands); Arnold, F.; Buerger, V.; Schneider, J. [Max-Planck-Inst. for Nuclear Physics, Heidelberg (Germany); Fischer, H.; Waibel, A. [Max-Planck-Inst. fuer Chemie, Mainz (Germany); Siegmund, P.C.; Wauben, W.M.F. [Koninklijk Nederlands Meteorologisch Inst., De Bilt (Netherlands); Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology

    1997-12-31

    In situ aircraft measurements of O{sub 3}, CO, HNO{sub 3}, and aerosol particles are presented, performed over the North Sea region in the summer lower stratosphere during the STREAM-II campaign (Stratosphere Troposphere Experiments by Aircraft Measurements). Elevated CO mixing ratios are attributed to mixing of polluted tropospheric air into the lowermost extra-tropical stratosphere. Model calculations illustrate that the O{sub 3} production efficiency of NO{sub x} is smaller than previously assumed, under conditions with relatively high HNO{sub 3} mixing ratios, as observed during STREAM-II. The model simulations further suggest a relatively high O{sub 3} production efficiency from CO oxidation, as a result of the relatively high ambient HNO{sub 3} and NO{sub x} concentrations, implying that upward transport of CO rich air enhances O{sub 3} production in the lowermost stratosphere. (author) 13 refs.

  3. Sensitivity of the radiative forcing by stratospheric sulfur geoengineering to the amount and strategy of the SO2injection studied with the LMDZ-S3A model

    Science.gov (United States)

    Kleinschmitt, Christoph; Boucher, Olivier; Platt, Ulrich

    2018-02-01

    The enhancement of the stratospheric sulfate aerosol layer has been proposed as a method of geoengineering to abate global warming. Previous modelling studies found that stratospheric aerosol geoengineering (SAG) could effectively compensate for the warming by greenhouse gases on the global scale, but also that the achievable cooling effect per sulfur mass unit, i.e. the forcing efficiency, decreases with increasing injection rate. In this study we use the atmospheric general circulation model LMDZ with the sectional aerosol module S3A to determine how the forcing efficiency depends on the injected amount of SO2, the injection height, and the spatio-temporal pattern of injection. We find that the forcing efficiency may decrease more drastically for larger SO2 injections than previously estimated. As a result, the net instantaneous radiative forcing does not exceed the limit of -2 W m-2 for continuous equatorial SO2 injections and it decreases (in absolute value) for injection rates larger than 20 Tg S yr-1. In contrast to other studies, the net radiative forcing in our experiments is fairly constant with injection height (in a range 17 to 23 km) for a given amount of SO2 injected. Also, spreading the SO2 injections between 30° S and 30° N or injecting only seasonally from varying latitudes does not result in a significantly larger (i.e. more negative) radiative forcing. Other key characteristics of our simulations include a consequent stratospheric heating, caused by the absorption of solar and infrared radiation by the aerosol, and changes in stratospheric dynamics, with a collapse of the quasi-biennial oscillation at larger injection rates, which has impacts on the resulting spatial aerosol distribution, size, and optical properties. But it has to be noted that the complexity and uncertainty of stratospheric processes cause considerable disagreement among different modelling studies of stratospheric aerosol geoengineering. This may be addressed through detailed

  4. The maintenance of elevated active chlorine levels in the Antarctic lower stratosphere through HCl null cycles

    Science.gov (United States)

    Müller, Rolf; Grooß, Jens-Uwe; Mannan Zafar, Abdul; Robrecht, Sabine; Lehmann, Ralph

    2018-03-01

    The Antarctic ozone hole arises from ozone destruction driven by elevated levels of ozone destroying (active) chlorine in Antarctic spring. These elevated levels of active chlorine have to be formed first and then maintained throughout the period of ozone destruction. It is a matter of debate how this maintenance of active chlorine is brought about in Antarctic spring, when the rate of formation of HCl (considered to be the main chlorine deactivation mechanism in Antarctica) is extremely high. Here we show that in the heart of the ozone hole (16-18 km or 85-55 hPa, in the core of the vortex), high levels of active chlorine are maintained by effective chemical cycles (referred to as HCl null cycles hereafter). In these cycles, the formation of HCl is balanced by immediate reactivation, i.e. by immediate reformation of active chlorine. Under these conditions, polar stratospheric clouds sequester HNO3 and thereby cause NO2 concentrations to be low. These HCl null cycles allow active chlorine levels to be maintained in the Antarctic lower stratosphere and thus rapid ozone destruction to occur. For the observed almost complete activation of stratospheric chlorine in the lower stratosphere, the heterogeneous reaction HCl + HOCl is essential; the production of HOCl occurs via HO2 + ClO, with the HO2 resulting from CH2O photolysis. These results are important for assessing the impact of changes of the future stratospheric composition on the recovery of the ozone hole. Our simulations indicate that, in the lower stratosphere, future increased methane concentrations will not lead to enhanced chlorine deactivation (through the reaction CH4 + Cl → HCl + CH3) and that extreme ozone destruction to levels below ≈ 0.1 ppm will occur until mid-century.

  5. Effects of the Mt. Pinatubo eruption on the radiative and chemical processes in the troposphere and stratosphere

    International Nuclear Information System (INIS)

    Kinnison, D.E.; Grant, K.E.; Connell, P.S.; Wuebbles, D.J.

    1992-01-01

    The LLNL 2-D zonally averaged chemical-radiative transport model of the global atmosphere was used to study the effects of the June 15, 1991 eruption of the Mt. Pinatubo volcano on stratospheric processes. SAGE-11 time-dependent aerosol surface area density and optical extinction data were used as input into the model. By the winter solstice, 1991, a maximum change in column ozone was observed in the equatorial region of -2% (with heterogeneous chemical reactions on sulfuric acid aerosols) and -5.5% (including heterogeneous reactions plus radiative feedbacks). Maximum local ozone decreases of 12% were derived in the equatorial region, at 25 km, for winter solstice 1991. Column NO 2 peaked (-14%) at 30 S in October 1991. Local concentrations of NO x , Cl x , and HO x , in the lower stratosphere, were calculated to have changed between 30 S and 30 N by -40%, +80%, and +60% respectively

  6. Unexpected high 35S concentration revealing strong downward transport of stratospheric air during the monsoon transitional period in East Asia

    Science.gov (United States)

    Lin, Mang; Zhang, Zhisheng; Su, Lin; Su, Binbin; Liu, Lanzhong; Tao, Jun; Fung, Jimmy C. H.; Thiemens, Mark H.

    2016-03-01

    October is the monsoon transitional period in East Asia (EA) involving a series of synoptic activities that may enhance the downward transport of stratospheric air to the planetary boundary layer (PBL). Here we use cosmogenic 35S in sulfate aerosols (35SO42-) as a tracer for air masses originating from the stratosphere and transported downward to quantify these mixing processes. From 1 year 35SO42- measurements (March 2014 to February 2015) at a background station in EA we find remarkably enhanced 35SO42- concentration (3150 atoms m-3) in October, the highest value ever reported for natural sulfate aerosols. A four-box 1-D model and meteorological analysis reveal that strong downward transport from the free troposphere is a vital process entraining aged stratospheric air masses to the PBL. The aged stratospheric masses are accumulated in the PBL, accelerating the SO2 transformation to SO42-. Implications for the tropospheric O3 budget and the CO2 biogeochemical cycle are discussed.

  7. ATMOS Stratospheric Deuterated Water and Implications for Tropospheric-Stratospheric Transport

    Science.gov (United States)

    Moyer, Elisabeth J.; Irion, Fredrick W.; Yung, Yuk L.; Gunson, Michael R.

    1996-01-01

    Measurements of the isotopic composition of stratospheric water by the ATMOS instrument are used to infer the convective history of stratospheric air. The average water vapor entering the stratosphere is found to be highly depleted of deuterium, with delta-D(sub w) of -670 +/- 80 (67% deuterium loss). Model calculations predict, however, that under conditions of thermodynamic equilibrium, dehydration to stratospheric mixing ratios should produce stronger depletion to delta-D(sub w) of -800 to 900 (80-90% deuterium loss). Deuterium enrichment of water vapor in ascending parcels can occur only in conditions of rapid convection; enrichments persisting into the stratosphere require that those conditions continue to near-tropopause altitudes. We conclude that either the predominant source of water vapor to the uppermost troposphere is enriched convective water, most likely evaporated cloud ice, or troposphere-stratosphere transport occurs closely associated with tropical deep convection.

  8. Tropospheric Aerosols

    Science.gov (United States)

    Buseck, P. R.; Schwartz, S. E.

    2003-12-01

    It is widely believed that "On a clear day you can see forever," as proclaimed in the 1965 Broadway musical of the same name. While an admittedly beautiful thought, we all know that this concept is only figurative. Aside from Earth's curvature and Rayleigh scattering by air molecules, aerosols - colloidal suspensions of solid or liquid particles in a gas - limit our vision. Even on the clearest day, there are billions of aerosol particles per cubic meter of air.Atmospheric aerosols are commonly referred to as smoke, dust, haze, and smog, terms that are loosely reflective of their origin and composition. Aerosol particles have arisen naturally for eons from sea spray, volcanic emissions, wind entrainment of mineral dust, wildfires, and gas-to-particle conversion of hydrocarbons from plants and dimethylsulfide from the oceans. However, over the industrial period, the natural background aerosol has been greatly augmented by anthropogenic contributions, i.e., those produced by human activities. One manifestation of this impact is reduced visibility (Figure 1). Thus, perhaps more than in other realms of geochemistry, when considering the composition of the troposphere one must consider the effects of these activities. The atmosphere has become a reservoir for vast quantities of anthropogenic emissions that exert important perturbations on it and on the planetary ecosystem in general. Consequently, much recent research focuses on the effects of human activities on the atmosphere and, through them, on the environment and Earth's climate. For these reasons consideration of the geochemistry of the atmosphere, and of atmospheric aerosols in particular, must include the effects of human activities. (201K)Figure 1. Impairment of visibility by aerosols. Photographs at Yosemite National Park, California, USA. (a) Low aerosol concentration (particulate matter of aerodynamic diameter less than 2.5 μm, PM2.5=0.3 μg m-3; particulate matter of aerodynamic diameter less than 10

  9. Stratospheric minor species vertical distributions during polar winter by balloon borne UV-Vis spectrometry

    Science.gov (United States)

    Pommereau, J. P.; Piquard, J.

    1994-01-01

    A light, relatively cheap and easy to operate balloonborne UV-visible spectrometer was designed for investigating ozone photochemistry in the Arctic winter. The instrument was flown 11 times during the European Arctic Stratospheric Ozone Experiment (EASOE) in winter 1991-92 in Northern Scandinavia. The first simultaneous measurements of vertical distributions of aerosols, PSC's, O3, NO2 and OClO inside the vortex during flight no. 6 on 16 January, in cold conditions are reported, which show that nitrogen oxides were almost absent (lower than 100 ppt) in the stratosphere below 22 km, while a layer of relatively large OClO concentration (15 ppt) was present at the altitude of the minimum temperature.

  10. Laboratory Investigations of Stratospheric Halogen Chemistry

    Science.gov (United States)

    Wine, Paul H.; Nicovich, J. Michael; Stickel, Robert E.; Hynes, Anthony J.

    1997-01-01

    A final report for the NASA-supported project on laboratory investigations of stratospheric halogen chemistry is presented. In recent years, this project has focused on three areas of research: (1) kinetic, mechanistic, and thermochemical studies of reactions which produce weakly bound chemical species of atmospheric interest; (2) development of flash photolysis schemes for studying radical-radical reactions of stratospheric interest; and (3) photochemistry studies of interest for understanding stratospheric chemistry. The first section of this paper contains a discussion of work which has not yet been published. All subsequent chapters contain reprints of published papers that acknowledge support from this grant.

  11. Solar research with stratospheric balloons

    Science.gov (United States)

    Vázquez, Manuel; Wittmann, Axel D.

    Balloons, driven by hot air or some gas lighter than air, were the first artificial machines able to lift payloads (including humans) from the ground. After some pioneering flights the study of the physical properties of the terrestrial atmosphere constituted the first scientific target. A bit later astronomers realized that the turbulence of the atmospheric layers above their ground-based telescopes deteriorated the image quality, and that balloons were an appropriate means to overcome, total or partially, this problem. Some of the most highly-resolved photographs and spectrograms of the sun during the 20th century were actually obtained by balloon-borne telescopes from the stratosphere. Some more recent projects of solar balloon astronomy will also be described.

  12. Climate Impacts From a Removal of Anthropogenic Aerosol Emissions

    Science.gov (United States)

    Samset, B. H.; Sand, M.; Smith, C. J.; Bauer, S. E.; Forster, P. M.; Fuglestvedt, J. S.; Osprey, S.; Schleussner, C.-F.

    2018-01-01

    Limiting global warming to 1.5 or 2.0°C requires strong mitigation of anthropogenic greenhouse gas (GHG) emissions. Concurrently, emissions of anthropogenic aerosols will decline, due to coemission with GHG, and measures to improve air quality. However, the combined climate effect of GHG and aerosol emissions over the industrial era is poorly constrained. Here we show the climate impacts from removing present-day anthropogenic aerosol emissions and compare them to the impacts from moderate GHG-dominated global warming. Removing aerosols induces a global mean surface heating of 0.5-1.1°C, and precipitation increase of 2.0-4.6%. Extreme weather indices also increase. We find a higher sensitivity of extreme events to aerosol reductions, per degree of surface warming, in particular over the major aerosol emission regions. Under near-term warming, we find that regional climate change will depend strongly on the balance between aerosol and GHG forcing.

  13. High Altitude Emissions of Black Carbon Aerosols: Potential Climate Implications

    Science.gov (United States)

    Satheesh, S. K.

    2017-12-01

    Synthesizing a series of ground-based and airborne measurements of aerosols over the Indian region during summer and pre-monsoon seasons have revealed the persistence of elevated absorbing aerosol layers over most of the Indian region; more than 50% of which located above clouds. Subsequent, in situ measurements of black carbon (BC) using high-altitude balloons, showed surprising layers with high concentrations in the middle and upper troposphere even at an altitude of 8 to 10 kms. Simultaneous measurements of the vertical thermal structure have shown localized warming due to BC absorption leading to large reduction in lapse rate and sharp temperature inversion, which in turn increases the atmospheric stability. This aerosol-induced stable layer is conducive for maintaining the black carbon layer longer at that level, leading thereby to further solar absorption and subsequently triggering dry convection. These observations support the `solar escalator' concept through which absorption-warming-convection cycles lead to self-lifting of BC to upper troposphere or even to lower stratosphere under favorable conditions in a matter of a few days. Employing an on-line regional chemistry transport model (WRF-Chem), incorporating aircraft emissions, it is shown that emissions from high-flying aircrafts as the most likely source of these elevated black carbon layers. These in-situ injected particles, produce significant warming of the thin air in those heights and lift these layers to even upper tropospheric/lower stratospheric heights, aided by the strong monsoonal convection occurring over the region, which are known to overshoot the tropical tropopause leading to injection of tropospheric air mass (along with its constituent aerosols) into the stratosphere, especially during monsoon season when the tropical tropopause layer is known to be thinnest. These simulations are further supported by the CALIPSO space-borne LIDAR derived extinction coefficient profiles. Based on

  14. Trajectory tracking control for underactuated stratospheric airship

    Science.gov (United States)

    Zheng, Zewei; Huo, Wei; Wu, Zhe

    2012-10-01

    Stratospheric airship is a new kind of aerospace system which has attracted worldwide developing interests for its broad application prospects. Based on the trajectory linearization control (TLC) theory, a novel trajectory tracking control method for an underactuated stratospheric airship is presented in this paper. Firstly, the TLC theory is described sketchily, and the dynamic model of the stratospheric airship is introduced with kinematics and dynamics equations. Then, the trajectory tracking control strategy is deduced in detail. The designed control system possesses a cascaded structure which consists of desired attitude calculation, position control loop and attitude control loop. Two sub-loops are designed for the position and attitude control loops, respectively, including the kinematics control loop and dynamics control loop. Stability analysis shows that the controlled closed-loop system is exponentially stable. Finally, simulation results for the stratospheric airship to track typical trajectories are illustrated to verify effectiveness of the proposed approach.

  15. The Effect of Cirrus Clouds on Water Vapor Transport in the Upper Troposphere and Lower Stratosphere

    Science.gov (United States)

    Lei, L.; McCormick, M. P.; Anderson, J.

    2017-12-01

    Water vapor plays an important role in the Earth's radiation budget and stratospheric chemistry. It is widely accepted that a large percentage of water vapor entering the stratosphere travels through the tropical tropopause and is dehydrated by the cold tropopause temperature. The vertical transport of water vapor is also affected by the radiative effects of cirrus clouds in the tropical tropopause layer. This latter effect of cirrus clouds was investigated in this research. The work focuses on the tropical and mid-latitude region (50N-50S). Water vapor data from the Microwave Limb Sounder (MLS) and cirrus cloud data from the Cloud-Aerosol Lidar and Infrared pathfinder Satellite Observation (CALIPSO) instruments were used to investigate the relationship between the water vapor and the occurrence of cirrus cloud. A 10-degree in longitude by 10-degree in latitude resolution was chosen to bin the MLS and CALIPSO data. The result shows that the maximum water vapor in the upper troposphere (below 146 hPa) is matched very well with the highest frequency of cirrus cloud occurrences. Maximum water vapor in the lower stratosphere (100 hPa) is partly matched with the maximum cirrus cloud occurrence in the summer time. The National Oceanic and Atmospheric Administration Interpolated Outgoing Longwave Radiation data and NCEP-DOE Reanalysis 2 wind data were used also to investigate the relationship between the water vapor entering the stratosphere, deep convection, and wind. Results show that maximum water vapor at 100 hPa coincides with the northern hemisphere summer-time anticyclone. The effects from both single-layer cirrus clouds and cirrus clouds above the anvil top on the water vapor entering the stratosphere were also studied and will be presented.

  16. Isolating the Roles of Different Forcing Agents in Global Stratospheric Temperature Changes Using Model Integrations with Incrementally Added Single Forcings

    Science.gov (United States)

    Aquila, V.; Swartz, W. H.; Waugh, D. W.; Colarco, P. R.; Pawson, S.; Polvani, L. M.; Stolarski, R. S.

    2016-01-01

    Satellite instruments show a cooling of global stratospheric temperatures over the whole data record (1979-2014). This cooling is not linear and includes two descending steps in the early 1980s and mid-1990s. The 1979-1995 period is characterized by increasing concentrations of ozone depleting substances (ODS) and by the two major volcanic eruptions of El Chichon (1982) and Mount Pinatubo (1991). The 1995-present period is characterized by decreasing ODS concentrations and by the absence of major volcanic eruptions. Greenhouse gas (GHG) concentrations increase over the whole time period. In order to isolate the roles of different forcing agents in the global stratospheric temperature changes, we performed a set of AMIP-style simulations using the NASA Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). We find that in our model simulations the cooling of the stratosphere from 1979 to present is mostly driven by changes in GHG concentrations in the middle and upper stratosphere and by GHG and ODS changes in the lower stratosphere. While the cooling trend caused by increasing GHGs is roughly constant over the satellite era, changing ODS concentrations cause a significant stratospheric cooling only up to the mid-1990s, when they start to decrease because of the implementation of the Montreal Protocol. Sporadic volcanic events and the solar cycle have a distinct signature in the time series of stratospheric temperature anomalies but do not play a statistically significant role in the long-term trends from 1979 to 2014. Several factors combine to produce the step-like behavior in the stratospheric temperatures: in the lower stratosphere, the flattening starting in the mid-1990s is due to the decrease in ozone-depleting substances; Mount Pinatubo and the solar cycle cause the abrupt steps through the aerosol-associated warming and the volcanically induced ozone depletion. In the middle and upper stratosphere, changes in solar irradiance are largely

  17. Pathways, Impacts, and Policies on Severe Aerosol Injections into the Atmosphere: 2011 Severe Atmospheric Aerosols Events Conference

    KAUST Repository

    Weil, Martin; Grassl, Hartmut; Hoshyaripour, Gholamali; Kloster, Silvia; Kominek, Jasmin; Misios, Stergios; Scheffran, Juergen; Starr, Steven; Stenchikov, Georgiy L.; Sudarchikova, Natalia; Timmreck, Claudia; Zhang, Dan; Kalinowski, Martin

    2012-01-01

    The 2011 severe atmospheric events conference, held on August 11-12, 2011, Hamburg, Germany, discussed climatic and environmental changes as a result of various kinds of huge injections of aerosols into the atmosphere and the possible consequences for the world population. Various sessions of the conference dealt with different aspects of large aerosol injections and severe atmospheric aerosol events along the geologic time scale. A presentation about radiative heating of aerosols as a self-lifting mechanism in the Australian forest fires discussed the question of how the impact of tropical volcanic eruptions depends on the eruption season. H.-F. Graf showed that cloud-resolving plume models are more suitable to predict the volcanic plume height and dispersion than one-dimensional models. G. Stenchikov pointed out that the absorbing smoke plumes in the upper troposphere can be partially mixed into the lower stratosphere because of the solar heating and lofting effect.

  18. Pathways, Impacts, and Policies on Severe Aerosol Injections into the Atmosphere: 2011 Severe Atmospheric Aerosols Events Conference

    KAUST Repository

    Weil, Martin

    2012-09-01

    The 2011 severe atmospheric events conference, held on August 11-12, 2011, Hamburg, Germany, discussed climatic and environmental changes as a result of various kinds of huge injections of aerosols into the atmosphere and the possible consequences for the world population. Various sessions of the conference dealt with different aspects of large aerosol injections and severe atmospheric aerosol events along the geologic time scale. A presentation about radiative heating of aerosols as a self-lifting mechanism in the Australian forest fires discussed the question of how the impact of tropical volcanic eruptions depends on the eruption season. H.-F. Graf showed that cloud-resolving plume models are more suitable to predict the volcanic plume height and dispersion than one-dimensional models. G. Stenchikov pointed out that the absorbing smoke plumes in the upper troposphere can be partially mixed into the lower stratosphere because of the solar heating and lofting effect.

  19. Issues in Stratospheric Ozone Depletion.

    Science.gov (United States)

    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

  20. Aerosols: connection between regional climatic change and air quality (Iupac Technical Report)

    NARCIS (Netherlands)

    Slanina, J.; Zhang, Y.H.

    2004-01-01

    yAerosols play an important role in all problems connected with air pollution, ranging from very local effects and human health problems to regional problems such as acid deposition and eutrophication up to continental and global questions such as stratospheric ozone loss and climatic change. In

  1. A Semi-empirical Model of the Stratosphere in the Climate System

    Science.gov (United States)

    Sodergren, A. H.; Bodeker, G. E.; Kremser, S.; Meinshausen, M.; McDonald, A.

    2014-12-01

    Chemistry climate models (CCMs) currently used to project changes in Antarctic ozone are extremely computationally demanding. CCM projections are uncertain due to lack of knowledge of future emissions of greenhouse gases (GHGs) and ozone depleting substances (ODSs), as well as parameterizations within the CCMs that have weakly constrained tuning parameters. While projections should be based on an ensemble of simulations, this is not currently possible due to the complexity of the CCMs. An inexpensive but realistic approach to simulate changes in stratospheric ozone, and its coupling to the climate system, is needed as a complement to CCMs. A simple climate model (SCM) can be used as a fast emulator of complex atmospheric-ocean climate models. If such an SCM includes a representation of stratospheric ozone, the evolution of the global ozone layer can be simulated for a wide range of GHG and ODS emissions scenarios. MAGICC is an SCM used in previous IPCC reports. In the current version of the MAGICC SCM, stratospheric ozone changes depend only on equivalent effective stratospheric chlorine (EESC). In this work, MAGICC is extended to include an interactive stratospheric ozone layer using a semi-empirical model of ozone responses to CO2and EESC, with changes in ozone affecting the radiative forcing in the SCM. To demonstrate the ability of our new, extended SCM to generate projections of global changes in ozone, tuning parameters from 19 coupled atmosphere-ocean general circulation models (AOGCMs) and 10 carbon cycle models (to create an ensemble of 190 simulations) have been used to generate probability density functions of the dates of return of stratospheric column ozone to 1960 and 1980 levels for different latitudes.

  2. Improved SAGE II cloud/aerosol categorization and observations of the Asian tropopause aerosol layer: 1989–2005

    Directory of Open Access Journals (Sweden)

    L. W. Thomason

    2013-05-01

    Full Text Available We describe the challenges associated with the interpretation of extinction coefficient measurements by the Stratospheric Aerosol and Gas Experiment (SAGE II in the presence of clouds. In particular, we have found that tropospheric aerosol analyses are highly dependent on a robust method for identifying when clouds affect the measured extinction coefficient. Herein, we describe an improved cloud identification method that appears to capture cloud/aerosol events more effectively than early methods. In addition, we summarize additional challenges to observing the Asian Tropopause Aerosol Layer (ATAL using SAGE II observations. Using this new approach, we perform analyses of the upper troposphere, focusing on periods in which the UTLS (upper troposphere/lower stratosphere is relatively free of volcanic material (1989–1990 and after 1996. Of particular interest is the Asian monsoon anticyclone where CALIPSO (Cloud-Aerosol Lidar Pathfinder Satellite Observations has observed an aerosol enhancement. This enhancement, called the ATAL, has a similar morphology to observed enhancements in long-lived trace gas species like CO. Since the CALIPSO record begins in 2006, the question of how long this aerosol feature has been present requires a new look at the long-lived SAGE II data sets despite significant hurdles to its use in the subtropical upper troposphere. We find that there is no evidence of ATAL in the SAGE II data prior to 1998. After 1998, it is clear that aerosol in the upper troposphere in the ATAL region is substantially enhanced relative to the period before that time. In addition, the data generally supports the presence of the ATAL beginning in 1999 and continuing through the end of the mission, though some years (e.g., 2003 are complicated by the presence of episodic enhancements most likely of volcanic origin.

  3. Stratospheric microbiology at 20 km over the Pacific Ocean

    Science.gov (United States)

    Smith, David J.; Griffin, Dale W.; Schuerger, Andrew C.

    2010-01-01

    An aerobiology sampling flight at 20 km was conducted on 28 April 2008 over the Pacific Ocean (36.5° N, 118–149° W), a period of time that coincided with the movement of Asian dust across the ocean. The aim of this study was to confirm the presence of viable bacteria and fungi within a transoceanic, atmospheric bridge and to improve the resolution of flight hardware processing techniques. Isolates of the microbial strains recovered were analyzed with ribosomal ribonucleic acid (rRNA) sequencing to identify bacterial species Bacillus sp., Bacillus subtilis, Bacillus endophyticus, and the fungal genus Penicillium. Satellite imagery and ground-based radiosonde observations were used to measure dust movement and characterize the high-altitude environment at the time of collection. Considering the atmospheric residency time (7–10 days), the extreme temperature regime of the environment (-75°C), and the absence of a mechanism that could sustain particulates at high altitude, it is unlikely that our samples indicate a permanent, stratospheric ecosystem. However, the presence of viable fungi and bacteria in transoceanic stratosphere remains relevant to understanding the distribution and extent of microbial life on Earth.

  4. The Unusual Southern Hemisphere Stratosphere Winter of 2002

    Science.gov (United States)

    Newman, Paul A.; Nash, Eric R.

    2003-01-01

    The southern hemisphere stratospheric winter of 2002 was the most unusual winter yet observed in the southern hemisphere climate record. Temperatures near the edge of the Antarctic polar vortex were considerably warmer than normal over the entire course of the winter. The polar night jet was considerably weaker than normal, and was displaced more poleward than has been observed in previous winters. These record high temperatures and weak jet resulted from a series of wave events that took place over the course of the winter. The first large event occurred on 15 May, and the final warming occurred on 25 October. The propagation of these wave events from the troposphere is diagnosed from time series of Eliassen-Palm flux vectors. The wave events tended to occur irregularly over the course of the winter, and pre-conditioned the polar night jet for the extremely large wave event of 22 September. This large wave event resulted in the first ever observed major stratospheric warming in the southern hemisphere. This wave event split the Antarctic ozone hole. The combined effect of the wave events of the 2002 winter resulted in the smallest ozone hole observed since 1988.

  5. SAGE II measurements of early Pinatubo aerosols

    Science.gov (United States)

    Mccormick, M. P.; Veiga, R. E.

    1992-01-01

    SAGE II satellite measurements of the Mt. Pinatubo eruption cloud in the stratosphere during June, July, and early August 1991 show that aerosols in the tropics reached as high as 29 km altitude with most of the cloud between 20 and 25 km. The most optically thick portions of the cloud covered latitudes from 10 deg S to 30 deg N during the early part of this period. By late July, high stratospheric optical depths were observed to at least 70 deg N, with the high values north of about 30 deg N from layers below 20 km. High pressure systems in both hemispheres were observed to be correlated with the movement of volcanic material at 21 km into the westerly jet stream at high southern latitudes and similarly to high northern latitudes at 16 km. By August, the entire Southern Hemisphere had experienced a 10-fold increase in optical depth relative to early July due to layers above 20 km. Initial mass calculations using SAGE II data place the aerosol produced from this eruption at 20 to 30 megatons, well above the 12 megatons produced by El Chichon.

  6. Aerosol filtration

    International Nuclear Information System (INIS)

    Klein, M.; Goossens, W.R.A.; De Smet, M.; Trine, J.; Hertschap, M.

    1984-01-01

    This report summarizes the work on the development of fibre metallic prefilters to be placed upstream of HEPA filters for the exhaust gases of nuclear process plants. Investigations at ambient and high temperature were carried out. Measurements of the filtration performance of Bekipor porous webs and sintered mats were performed in the AFLT (aerosol filtration at low temperature) unit with a throughput of 15 m 3 /h. A parametric study on the influence of particle size, fibre diameter, number of layers and superficial velocity led to the optimum choice of the working parameters. Three selected filter types were then tested with polydisperse aerosols using a candle-type filter configuration or a flat-type filter configuration. The small-diameter candle type is not well suited for a spraying nozzles regeneration system so that only the flat-type filter was retained for high-temperature tests. A high-temperature test unit (AFHT) with a throughput of 8 to 10 m 3 /h at 400 0 C was used to test the three filter types with an aerosol generated by high-temperature calcination of a simulated nitric acid waste solution traced with 134 Cs. The regeneration of the filter by spray washing and the effect of the regeneration on the filter performance was studied for the three filter types. The porous mats have a higher dust loading capacity than the sintered web which means that their regeneration frequency can be kept lower

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

    Science.gov (United States)

    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.

  8. Observation of stratospheric ozone with NIES lidar system in Tsukuba, Japan

    International Nuclear Information System (INIS)

    Nakane, H.; Hayashida, S.; Sasano, Y.; Sugimoto, N.; Matsui, I.; Minato, A.

    1992-01-01

    Lidars are expected to play important roles in an international monitoring network of the stratosphere such as the Network for the Detection of Stratospheric Change (NDSC). The National Institute for Environmental Studies (NIES) in Tsukuba constructed an ozone lidar system in March 1988 and started observation in August 1988. The lidar system has a 2-m telescope and injection locked XeCl and XeF excimer lasers which can measure ozone profiles (15-45 km) and temperature profiles (30-80 km). From December 1991, lidar observations have been carried out in which the second Stokes line of the stimulated Raman scattering of a KrF laser has been used. Ozone profiles obtained with the NIES lidar system are compared with the data provided by the SAGE II satellite sensor. Results showed good agreement for the individual and the zonal mean profiles. Variations of ozone with various time scales at each altitude can be studied using the data obtained with the NIES ozone lidar system. Seasonal variations are easily found at 20 km, 30 km, and 35 km, which are qualitatively understood as a result of dynamical and photochemical effects. Systematic errors of ozone profiles due to the Pinatubo stratospheric aerosols have been detected using multi-wavelength observation

  9. TOMS Absorbing Aerosol Index

    Data.gov (United States)

    Washington University St Louis — TOMS_AI_G is an aerosol related dataset derived from the Total Ozone Monitoring Satellite (TOMS) Sensor. The TOMS aerosol index arises from absorbing aerosols such...

  10. Effects of tropospheric aerosols on radiative flux calculations at UV and visible wavelengths

    International Nuclear Information System (INIS)

    Grossman, A.S.; Grant, K.E.

    1994-08-01

    The surface fluxes in the wavelength range 175 to 735nm have been calculated for an atmosphere which contains a uniformly mixed aerosol layer of thickness 1km at the earth's surface. Two different aerosol types were considered, a rural aerosol, and an urban aerosol. The visibility range for the aerosol layers was 95 to 15 km. Surface flux ratios (15km/95km) were in agreement with previously published results for the rural aerosol layer to within about 2%. The surface flux ratios vary from 7 to 14% for the rural aerosol layer and from 13 to 23% for the urban aerosol layer over the wavelength range. A tropospheric radiative forcing of about 1.3% of the total tropospheric flux was determined for the 95km to 15km visibility change in the rural aerosol layer, indicating the potential of tropospheric feedback effects on the surface flux changes. This effect was found to be negligible for the urban aerosol layer. Stratospheric layer heating rate changes due to visibility changes in either the rural or urban aerosol layer were found to be negligible

  11. Sources and sinks of stratospheric water vapor

    International Nuclear Information System (INIS)

    Ellsaesser, H.W.

    1979-11-01

    A tutorial review of the understanding of stratospheric H 2 O and the processes controlling it is presented. Paradoxes posed by currently available observational data are cited and suggestions made as to how they might be resolved. Such resolution appears to require: that the bulk of our current data provides unrepresentative and misleading vertical and latitudinal H 2 O gradients immediately downstream from the tropical tropopause; and, that there exists within the troposphere a mechanism different from or in addition to the tropical tropopause cold trap for drying air to the mixing ratios found in the lower stratosphere. Satisfaction of these requirements will reconcile much heretofore puzzling observational data and will obviate the necessity for a stratospheric sink for H 2 O

  12. Study of the behaviour of artificial radioactive aerosols. Applications to some problems of atmospheric circulation (1963)

    International Nuclear Information System (INIS)

    Lambert, G.

    1963-11-01

    The aim of this work, consists in the examination of the behaviour of radioactive aerosols produced in the atmosphere by nuclear explosions, in order to deduce the most general laws governing atmospheric circulation and diffusion. After having given a general table of the radioactive aerosols present the authors consider the validity and the precision of the measurement methods and the concentration of the aerosols at ground level and in the upper atmosphere, as well as their deposition on the ground. The existence is thus demonstrated of a tropospheric equatorial barrier and of discontinuous and seasonal aspects of stratosphere-troposphere transfers. The role is shown of precipitations and dry auto-filtration in the lower atmosphere cleaning processes. This work makes it possible to describe the general behaviour of dust from the stratosphere, and to improve the total radioactive contamination of the globe. (author) [fr

  13. The economics and ethics of aerosol geoengineering strategies

    Science.gov (United States)

    Goes, Marlos; Keller, Klaus; Tuana, Nancy

    2010-05-01

    Anthropogenic greenhouse gas emissions are changing the Earth's climate and impose substantial risks for current and future generations. What are scientifically sound, economically viable, and ethically defendable strategies to manage these climate risks? Ratified international agreements call for a reduction of greenhouse gas emissions to avoid dangerous anthropogenic interference with the climate system. Recent proposals, however, call for a different approach: geoengineering climate by injecting aerosol precursors into the stratosphere. Published economic studies typically neglect the risks of aerosol geoengineering due to (i) a potential failure to sustain the aerosol forcing and (ii) due to potential negative impacts associated with aerosol forcings. Here we use a simple integrated assessment model of climate change to analyze potential economic impacts of aerosol geoengineering strategies over a wide range of uncertain parameters such as climate sensitivity, the economic damages due to climate change, and the economic damages due to aerosol geoengineering forcings. The simplicity of the model provides the advantages of parsimony and transparency, but it also imposes considerable caveats. For example, the analysis is based on a globally aggregated model and is hence silent on intragenerational distribution of costs and benefits. In addition, the analysis neglects the effects of future learning and is based on a simple representation of climate change impacts. We use this integrated assessment model to show three main points. First, substituting aerosol geoengineering for the reduction of greenhouse gas emissions can fail the test of economic efficiency. One key to this finding is that a failure to sustain the aerosol forcing can lead to sizeable and abrupt climatic changes. The monetary damages due to such a discontinuous aerosol geoengineering can dominate the cost-benefit analysis because the monetary damages of climate change are expected to increase with

  14. Equatorial waves in the stratosphere of Uranus

    Science.gov (United States)

    Hinson, David P.; Magalhaes, Julio A.

    1991-01-01

    Analyses of radio occultation data from Voyager 2 have led to the discovery and characterization of an equatorial wave in the Uranus stratosphere. The observed quasi-periodic vertical atmospheric density variations are in close agreement with theoretical predictions for a wave that propagates vertically through the observed background structure of the stratosphere. Quantitative comparisons between measurements obtained at immersion and at emersion yielded constraints on the meridional and zonal structure of the wave; the fact that the two sets of measurements are correlated suggests a wave of planetary scale. Two equatorial wave models are proposed for the wave.

  15. Climatic impacts of stratospheric geoengineering with sulfate, black carbon and titania injection

    Directory of Open Access Journals (Sweden)

    A. C. Jones

    2016-03-01

    Full Text Available In this paper, we examine the potential climatic effects of geoengineering by sulfate, black carbon and titania injection against a baseline RCP8.5 scenario. We use the HadGEM2-CCS model to simulate scenarios in which the top-of-the-atmosphere radiative imbalance due to rising greenhouse gas concentrations is offset by sufficient aerosol injection throughout the 2020–2100 period. We find that the global-mean temperature is effectively maintained at historical levels for the entirety of the period for all three aerosol-injection scenarios, though there is a wide range of side-effects which are discussed in detail. The most prominent conclusion is that although the BC injection rate necessary to produce an equivalent global mean temperature response is much lower, the severity of stratospheric temperature changes (> +70 °C and precipitation impacts effectively exclude BC from being a viable option for geoengineering. Additionally, while it has been suggested that titania would be an effective particle because of its high scattering efficiency, it also efficiently absorbs solar ultraviolet radiation producing a significant stratospheric warming (> +20 °C. As injection rates and climatic impacts for titania are close to those for sulfate, there appears to be little benefit in terms of climatic influence of using titania when compared to the injection of sulfur dioxide, which has the added benefit of being well-modeled through extensive research that has been carried out on naturally occurring explosive volcanic eruptions.

  16. Reevaluation of Stratospheric Ozone Trends From SAGE II Data Using a Simultaneous Temporal and Spatial Analysis

    Science.gov (United States)

    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.

  17. PIXE analysis of atmospheric aerosol and hydrometeor particles

    International Nuclear Information System (INIS)

    Groeneveld, K.O.; Hofmann, D.; Georgii, H.W.

    1993-01-01

    Atmospheric aerosol and hydrometeor particles act decisively on our weather, climate and thereby on all living conditions on Earth. Particle induced X-ray emission (PIXE) analysis has been demonstrated to be an extremely valuable tool for quantitative and qualitative elemental analysis of aerosol particles and hydrometeors. Reliability and detection limits of PIXE are determined, including comparison with other techniques. Aerosol particles are collected on a global scale in ground stations, or by ships and by planes. Correlation between wind direction and elemental composition of atmospheric aerosols, elemental particle size distributions of the tropospheric aerosol, aerosol elemental composition in particle size fractions in the case of long range transport, transport pathways of pollution aerosol, and trace element content precipitation are discussed. Hydrometeors were studied in the form of rain, snow, fog, dew and frost. The time dependence of the melting process of snow was studied in detail, in particular the washout phenomena of impurity ions. (orig.)

  18. Mandelbrot's Extremism

    NARCIS (Netherlands)

    Beirlant, J.; Schoutens, W.; Segers, J.J.J.

    2004-01-01

    In the sixties Mandelbrot already showed that extreme price swings are more likely than some of us think or incorporate in our models.A modern toolbox for analyzing such rare events can be found in the field of extreme value theory.At the core of extreme value theory lies the modelling of maxima

  19. Composite Materials With Uncured Epoxy Matrix Exposed in Stratosphere During NASA Stratospheric Balloon Flight

    Science.gov (United States)

    Kondyurin, Alexey; Kondyurina, Irina; Bilek, Marcela; de Groh, Kim K.

    2013-01-01

    A cassette of uncured composite materials with epoxy resin matrixes was exposed in the stratosphere (40 km altitude) over three days. Temperature variations of -76 to 32.5C and pressure up to 2.1 torr were recorded during flight. An analysis of the chemical structure of the composites showed, that the polymer matrix exposed in the stratosphere becomes crosslinked, while the ground control materials react by way of polymerization reaction of epoxy groups. The space irradiations are considered to be responsible for crosslinking of the uncured polymers exposed in the stratosphere. The composites were cured on Earth after landing. Analysis of the cured composites showed that the polymer matrix remains active under stratospheric conditions. The results can be used for predicting curing processes of polymer composites in a free space environment during an orbital space flight.

  20. Aerosol scrubbers

    International Nuclear Information System (INIS)

    Sheely, W.F.

    1986-01-01

    The Submerged Gravel Scrubber is an air cleaning system developed by the Department of Energy's Liquid Metal Reactor Program. The Scrubber System has been patented by the Department of Energy. This technology is being transferred to industry by the DOE. Its basic principles can be adapted for individual applications and the commercialized version can be used to perform a variety of tasks. The gas to be cleaned is percolated through a continuously washed gravel bed. The passage of the gas through the gravel breaks the stream into many small bubbles rising in a turbulent body of water. These conditions allow very highly efficient removal of aerosols from the gas

  1. Calibration of aerosol radiometers. Special aerosol sources

    International Nuclear Information System (INIS)

    Belkina, S.K.; Zalmanzon, Yu.E.; Kuznetsov, Yu.V.; Fertman, D.E.

    1988-01-01

    Problems of calibration of artificial aerosol radiometry and information-measurement systems of radiometer radiation control, in particular, are considered. Special aerosol source is suggested, which permits to perform certification and testing of aerosol channels of the systems in situ without the dismantling

  2. The chemistry of stratospheric ozone

    International Nuclear Information System (INIS)

    Kurylo, M.J.

    1990-01-01

    Compelling observational evidence shows that the chemical composition of the atmosphere is changing on a global scale at a rapid rate. The atmospheric concentrations of carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O), and chloroflourocarbons (CFCs) 11 (CFCl 3 ) and 12 (CF 2 Cl 2 ) are currently increasing at rate ranging from 0.2 to 5% per year. The concentrations of other cases, including CFC 113 (C 2 F 3 Cl 3 ) and halons 121 (CF 2 ClBr) and 1301 (CF 3 Br), important in the ozone depletion and global warming issues, are also increasing (at even faster rates). These changes in atmospheric composition reflect, on one part, the metabolism of the biosphere and, on another, the broad range of influencing human activities, including industrial, agricultural, and combustion practices. The only known sources of the CFCs and halons are industrial production prior to their use as aerosol propellants, refrigerants, foam blowing agents, solvents, and fire retardants. One of our greatest difficulties in accurately predicting future changes in ozone or global warming is our inability to predict the future atmospheric concentrations of these gases. This paper discusses the role of the biosphere in regulating the emissions of gases such as CH 4 , CO 2 , N 2 O, and methyl chloride (CH 3 Cl) to the atmosphere as well as the most probable future industrial release rates of the CFCs, halons, N 2 O, carbon monoxide (CO), and CO 2 , which depend upon a variety of economic, social, and political factors

  3. Triton - Stratospheric molecules and organic sediments

    Science.gov (United States)

    Thompson, W. Reid; Singh, Sushil K.; Khare, B. N.; Sagan, Carl

    1989-01-01

    Continuous-flow plasma discharge techniques show production rates of hydrocarbons and nitriles in N2 + CH4 atmospheres appropriate to the stratosphere of Titan, and indicate that a simple eddy diffusion model together with the observed electron flux quantitatively matches the Voyager IRIS observations for all the hydrocarbons, except for the simplest ones. Charged particle chemistry is very important in Triton's stratosphere. In the more CH4-rich case of Titan, many hydrocarbons and nitriles are produced in high yield. If N2 is present, the CH4 fraction is low, but hydrocarbons and nitriles are produced in fair yield, abundances of HCN and C2H2 in Triton's stratosphere exceed 10 to the 19th molecules/sq cm per sec, and NCCN, C3H4, and other species are predicted to be present. These molecules may be detected by IRIS if the stratosphere is as warm as expected. Both organic haze and condensed gases will provide a substantial UV and visible opacity in Triton's atmosphere.

  4. Stratospheric tritium sampling. Final progress report

    International Nuclear Information System (INIS)

    Mason, A.S.; Oestlund, H.G.

    1985-09-01

    Stratospheric tritium sampling was part of Project Airstream (sponsored by the US Department of Energy) between 1975 and 1983. Data from the final deployment in November 1983 are reported here, and the results of the 9 years of effort are summarized. 9 refs., 2 figs., 2 tabs

  5. Stratospheric General Circulation with Chemistry Model (SGCCM)

    Science.gov (United States)

    Rood, Richard B.; Douglass, Anne R.; Geller, Marvin A.; Kaye, Jack A.; Nielsen, J. Eric; Rosenfield, Joan E.; Stolarski, Richard S.

    1990-01-01

    In the past two years constituent transport and chemistry experiments have been performed using both simple single constituent models and more complex reservoir species models. Winds for these experiments have been taken from the data assimilation effort, Stratospheric Data Analysis System (STRATAN).

  6. Stratospheric Impact of Varying Sea Surface Temperatures

    Science.gov (United States)

    Newman, Paul A.; Nash, Eric R.; Nielsen, Jon E.; Waugh, Darryn; Pawson, Steven

    2004-01-01

    The Finite-Volume General Circulation Model (FVGCM) has been run in 50 year simulations with the: 1) 1949-1999 Hadley Centre sea surface temperatures (SST), and 2) a fixed annual cycle of SSTs. In this presentation we first show that the 1949-1999 FVGCM simulation produces a very credible stratosphere in comparison to an NCEP/NCAR reanalysis climatology. In particular, the northern hemisphere has numerous major and minor stratospheric warming, while the southern hemisphere has only a few over the 50-year simulation. During the northern hemisphere winter, temperatures are both warmer in the lower stratosphere and the polar vortex is weaker than is found in the mid-winter southern hemisphere. Mean temperature differences in the lower stratosphere are shown to be small (less than 2 K), and planetary wave forcing is found to be very consistent with the climatology. We then will show the differences between our varying SST simulation and the fixed SST simulation in both the dynamics and in two parameterized trace gases (ozone and methane). In general, differences are found to be small, with subtle changes in planetary wave forcing that lead to reduced temperatures in the SH and increased temperatures in the NH.

  7. Aerosol influence on energy balance of the middle atmosphere of Jupiter.

    Science.gov (United States)

    Zhang, Xi; West, Robert A; Irwin, Patrick G J; Nixon, Conor A; Yung, Yuk L

    2015-12-22

    Aerosols are ubiquitous in planetary atmospheres in the Solar System. However, radiative forcing on Jupiter has traditionally been attributed to solar heating and infrared cooling of gaseous constituents only, while the significance of aerosol radiative effects has been a long-standing controversy. Here we show, based on observations from the NASA spacecraft Voyager and Cassini, that gases alone cannot maintain the global energy balance in the middle atmosphere of Jupiter. Instead, a thick aerosol layer consisting of fluffy, fractal aggregate particles produced by photochemistry and auroral chemistry dominates the stratospheric radiative heating at middle and high latitudes, exceeding the local gas heating rate by a factor of 5-10. On a global average, aerosol heating is comparable to the gas contribution and aerosol cooling is more important than previously thought. We argue that fractal aggregate particles may also have a significant role in controlling the atmospheric radiative energy balance on other planets, as on Jupiter.

  8. Pinatubo Emulation in Multiple Models (POEMs): co-ordinated experiments in the ISA-MIP model intercomparison activity component of the SPARC Stratospheric Sulphur and it's Role in Climate initiative (SSiRC)

    Science.gov (United States)

    Lee, Lindsay; Mann, Graham; Carslaw, Ken; Toohey, Matthew; Aquila, Valentina

    2016-04-01

    The World Climate Research Program's SPARC initiative has a new international activity "Stratospheric Sulphur and its Role in Climate" (SSiRC) to better understand changes in stratospheric aerosol and precursor gaseous sulphur species. One component of SSiRC involves an intercomparison "ISA-MIP" of composition-climate models that simulate the stratospheric aerosol layer interactively. Within PoEMS each modelling group will run a "perturbed physics ensemble" (PPE) of interactive stratospheric aerosol (ISA) simulations of the Pinatubo eruption, varying several uncertain parameters associated with the eruption's SO2 emissions and model processes. A powerful new technique to quantify and attribute sources of uncertainty in complex global models is described by Lee et al. (2011, ACP). The analysis uses Gaussian emulation to derive a probability density function (pdf) of predicted quantities, essentially interpolating the PPE results in multi-dimensional parameter space. Once trained on the ensemble, a Monte Carlo simulation with the fast Gaussian emulator enabling a full variance-based sensitivity analysis. The approach has already been used effectively by Carslaw et al., (2013, Nature) to quantify the uncertainty in the cloud albedo effect forcing from a 3D global aerosol-microphysics model allowing to compare the sensitivy of different predicted quantities to uncertainties in natural and anthropogenic emissions types, and structural parameters in the models. Within ISA-MIP, each group will carry out a PPE of runs, with the subsequent analysis with the emulator assessing the uncertainty in the volcanic forcings predicted by each model. In this poster presentation we will give an outline of the "PoEMS" analysis, describing the uncertain parameters to be varied and the relevance to further understanding differences identified in previous international stratospheric aerosol assessments.

  9. Stratospheric experiments on curing of composite materials

    Science.gov (United States)

    Chudinov, Viacheslav; Kondyurin, Alexey; Svistkov, Alexander L.; Efremov, Denis; Demin, Anton; Terpugov, Viktor; Rusakov, Sergey

    2016-07-01

    Future space exploration requires a large light-weight structure for habitats, greenhouses, space bases, space factories and other constructions. A new approach enabling large-size constructions in space relies on the use of the technology of polymerization of fiber-filled composites with a curable polymer matrix applied in the free space environment on Erath orbit. In orbit, the material is exposed to high vacuum, dramatic temperature changes, plasma of free space due to cosmic rays, sun irradiation and atomic oxygen (in low Earth orbit), micrometeorite fluence, electric charging and microgravitation. The development of appropriate polymer matrix composites requires an understanding of the chemical processes of polymer matrix curing under the specific free space conditions to be encountered. The goal of the stratospheric flight experiment is an investigation of the effect of the stratospheric conditions on the uncured polymer matrix of the composite material. The unique combination of low residual pressure, high intensity UV radiation including short-wave UV component, cosmic rays and other aspects associated with solar irradiation strongly influences the chemical processes in polymeric materials. We have done the stratospheric flight experiments with uncured composites (prepreg). A balloon with payload equipped with heater, temperature/pressure/irradiation sensors, microprocessor, carrying the samples of uncured prepreg has been launched to stratosphere of 25-30 km altitude. After the flight, the samples have been tested with FTIR, gel-fraction, tensile test and DMA. The effect of cosmic radiation has been observed. The composite was successfully cured during the stratospheric flight. The study was supported by RFBR grants 12-08-00970 and 14-08-96011.

  10. Aerosols and the lungs

    International Nuclear Information System (INIS)

    1987-01-01

    The lectures of the colloquium are discussed in summary form. There were 5 lectures on aerosol deposition, 5 on aerosol elimination, 7 on toxicology, and 7 on the uses of aerosols in medical therapy. In some cases aerosols with radioactive labels were used. Several lectures reviewed the kinetics and toxicology of airborne environmental pollutants. (MG) [de

  11. Interim Proposal for Molecular Beam Studies of Surfactants in Sulfuric Acid Aerosols: Comparisons Between Hydrocarbon and Fluorocarbon Alcohols

    National Research Council Canada - National Science Library

    Nathanson, Gilbert

    2003-01-01

    .... These processes include the acid-catalyzed reactions of HCI and HBr with CIONO2 (BrONO2) and HOCI (HOBr) to generate photoactive halogen molecules, particularly in colder regions of the stratosphere where they are more soluble in the water-rich aerosols...

  12. Aerosol climate time series from ESA Aerosol_cci (Invited)

    Science.gov (United States)

    Holzer-Popp, T.

    2013-12-01

    Within the ESA Climate Change Initiative (CCI) the Aerosol_cci project (mid 2010 - mid 2013, phase 2 proposed 2014-2016) has conducted intensive work to improve algorithms for the retrieval of aerosol information from European sensors AATSR (3 algorithms), PARASOL, MERIS (3 algorithms), synergetic AATSR/SCIAMACHY, OMI and GOMOS. Whereas OMI and GOMOS were used to derive absorbing aerosol index and stratospheric extinction profiles, respectively, Aerosol Optical Depth (AOD) and Angstrom coefficient were retrieved from the other sensors. Global datasets for 2008 were produced and validated versus independent ground-based data and other satellite data sets (MODIS, MISR). An additional 17-year dataset is currently generated using ATSR-2/AATSR data. During the three years of the project, intensive collaborative efforts were made to improve the retrieval algorithms focusing on the most critical modules. The team agreed on the use of a common definition for the aerosol optical properties. Cloud masking was evaluated, but a rigorous analysis with a pre-scribed cloud mask did not lead to improvement for all algorithms. Better results were obtained using a post-processing step in which sudden transitions, indicative of possible occurrence of cloud contamination, were removed. Surface parameterization, which is most critical for the nadir only algorithms (MERIS and synergetic AATSR / SCIAMACHY) was studied to a limited extent. The retrieval results for AOD, Ångström exponent (AE) and uncertainties were evaluated by comparison with data from AERONET (and a limited amount of MAN) sun photometer and with satellite data available from MODIS and MISR. Both level2 and level3 (gridded daily) datasets were validated. Several validation metrics were used (standard statistical quantities such as bias, rmse, Pearson correlation, linear regression, as well as scoring approaches to quantitatively evaluate the spatial and temporal correlations against AERONET), and in some cases

  13. Infrared remote sensing of atmospheric aerosols; Apports du sondage infrarouge a l'etude des aerosols atmospheriques

    Energy Technology Data Exchange (ETDEWEB)

    Pierangelo, C.

    2005-09-15

    The 2001 report from the Intergovernmental Panel on Climate Change emphasized the very low level of understanding of atmospheric aerosol effects on climate. These particles originate either from natural sources (dust, volcanic aerosols...) or from anthropogenic sources (sulfates, soot...). They are one of the main sources of uncertainty on climate change, partly because they show a very high spatio-temporal variability. Observation from space, being global and quasi-continuous, is therefore a first importance tool for aerosol studies. Remote sensing in the visible domain has been widely used to obtain a better characterization of these particles and their effect on solar radiation. On the opposite, remote sensing of aerosols in the infrared domain still remains marginal. Yet, not only the knowledge of the effect of aerosols on terrestrial radiation is needed for the evaluation of their total radiative forcing, but also infrared remote sensing provides a way to retrieve other aerosol characteristics (observations are possible at night and day, over land and sea). In this PhD dissertation, we show that aerosol optical depth, altitude and size can be retrieved from infrared sounder observations. We first study the sensitivity of aerosol optical properties to their micro-physical properties, we then develop a radiative transfer code for scattering medium adapted to the very high spectral resolution of the new generation sounder NASA-Aqua/AIRS, and we finally focus on the inverse problem. The applications shown here deal with Pinatubo stratospheric volcanic aerosol, observed with NOAA/HIRS, and with the building of an 8 year climatology of dust over sea and land from this sounder. Finally, from AIRS observations, we retrieve the optical depth at 10 {mu}m, the average altitude and the coarse mode effective radius of mineral dust over sea. (author)

  14. Infrared remote sensing of atmospheric aerosols; Apports du sondage infrarouge a l'etude des aerosols atmospheriques

    Energy Technology Data Exchange (ETDEWEB)

    Pierangelo, C

    2005-09-15

    The 2001 report from the Intergovernmental Panel on Climate Change emphasized the very low level of understanding of atmospheric aerosol effects on climate. These particles originate either from natural sources (dust, volcanic aerosols...) or from anthropogenic sources (sulfates, soot...). They are one of the main sources of uncertainty on climate change, partly because they show a very high spatio-temporal variability. Observation from space, being global and quasi-continuous, is therefore a first importance tool for aerosol studies. Remote sensing in the visible domain has been widely used to obtain a better characterization of these particles and their effect on solar radiation. On the opposite, remote sensing of aerosols in the infrared domain still remains marginal. Yet, not only the knowledge of the effect of aerosols on terrestrial radiation is needed for the evaluation of their total radiative forcing, but also infrared remote sensing provides a way to retrieve other aerosol characteristics (observations are possible at night and day, over land and sea). In this PhD dissertation, we show that aerosol optical depth, altitude and size can be retrieved from infrared sounder observations. We first study the sensitivity of aerosol optical properties to their micro-physical properties, we then develop a radiative transfer code for scattering medium adapted to the very high spectral resolution of the new generation sounder NASA-Aqua/AIRS, and we finally focus on the inverse problem. The applications shown here deal with Pinatubo stratospheric volcanic aerosol, observed with NOAA/HIRS, and with the building of an 8 year climatology of dust over sea and land from this sounder. Finally, from AIRS observations, we retrieve the optical depth at 10 {mu}m, the average altitude and the coarse mode effective radius of mineral dust over sea. (author)

  15. Global distribution of total ozone and lower stratospheric temperature variations

    Directory of Open Access Journals (Sweden)

    W. Steinbrecht

    2003-01-01

    Full Text Available This study gives an overview of interannual variations of total ozone and 50 hPa temperature. It is based on newer and longer records from the 1979 to 2001 Total Ozone Monitoring Spectrometer (TOMS and Solar Backscatter Ultraviolet (SBUV instruments, and on US National Center for Environmental Prediction (NCEP reanalyses. Multiple linear least squares regression is used to attribute variations to various natural and anthropogenic explanatory variables. Usually, maps of total ozone and 50 hPa temperature variations look very similar, reflecting a very close coupling between the two. As a rule of thumb, a 10 Dobson Unit (DU change in total ozone corresponds to a 1 K change of 50 hPa temperature. Large variations come from the linear trend term, up to -30 DU or -1.5 K/decade, from terms related to polar vortex strength, up to 50 DU or 5 K (typical, minimum to maximum, from tropospheric meteorology, up to 30 DU or 3 K, or from the Quasi-Biennial Oscillation (QBO, up to 25 DU or 2.5 K. The 11-year solar cycle, up to 25 DU or 2.5 K, or El Niño/Southern Oscillation (ENSO, up to 10 DU or 1 K, are contributing smaller variations. Stratospheric aerosol after the 1991 Pinatubo eruption lead to warming up to 3 K at low latitudes and to ozone depletion up to 40 DU at high latitudes. Variations attributed to QBO, polar vortex strength, and to a lesser degree to ENSO, exhibit an inverse correlation between low latitudes and higher latitudes. Variations related to the solar cycle or 400 hPa temperature, however, have the same sign over most of the globe. Variations are usually zonally symmetric at low and mid-latitudes, but asymmetric at high latitudes. There, position and strength of the stratospheric anti-cyclones over the Aleutians and south of Australia appear to vary with the phases of solar cycle, QBO or ENSO.

  16. The Asian Tropopause Aerosol Layer: Balloon-Borne Measurements, Satellite Observations and Modeling Approaches

    Science.gov (United States)

    Fairlie, T. D.; Vernier, J.-P.; Natarajan, M.; Deshler, Terry; Liu, H.; Wegner, T.; Baker, N.; Gadhavi, H.; Jayaraman, A.; Pandit, A.; hide

    2016-01-01

    Satellite observations and numerical modeling studies have demonstrated that the Asian Summer Monsoon (ASM) can provide a conduit for gas-phase pollutants in south Asia to reach the lower stratosphere. Now, observations from the CALIPSO satellite have revealed the Asian Tropopause Aerosol Layer (ATAL), a summertime accumulation of aerosols associated with ASM anticyclone, in the upper troposphere and lower stratosphere (UTLS). The ATAL has potential implications for regional cloud properties, climate, and chemical processes in the UTLS. Here, we show in situ measurements from balloon-borne instrumentation, aircraft and satellite observations, combined with trajectory and chemical transport model (CTM) simulations to explore the origin, composition, physical and optical properties of aerosols in the ATAL. In particular, we show balloon-based observations from our BATAL-2015 field campaign to India and Saudi Arabia in summer 2015, including in situ backscatter measurements from COBALD instruments, and some of the first observations of size and volatility of aerosols in the ATAL layer using optical particle counters (OPCs). Back trajectory calculations initialized from CALIPSO observations point to deep convection over North India as a principal source of ATAL aerosols. Available aircraft observations suggest significant sulfur and carbonaceous contributions to the ATAL, which is supported by simulations using the GEOS-Chem CTM. Source elimination studies conducted with the GEOS-Chem indicate that 80-90% of ATAL aerosols originate from south Asian sources, in contrast with some earlier studies.

  17. Aerosol typing - key information from aerosol studies

    Science.gov (United States)

    Mona, Lucia; Kahn, Ralph; Papagiannopoulos, Nikolaos; Holzer-Popp, Thomas; Pappalardo, Gelsomina

    2016-04-01

    Aerosol typing is a key source of aerosol information from ground-based and satellite-borne instruments. Depending on the specific measurement technique, aerosol typing can be used as input for retrievals or represents an output for other applications. Typically aerosol retrievals require some a priori or external aerosol type information. The accuracy of the derived aerosol products strongly depends on the reliability of these assumptions. Different sensors can make use of different aerosol type inputs. A critical review and harmonization of these procedures could significantly reduce related uncertainties. On the other hand, satellite measurements in recent years are providing valuable information about the global distribution of aerosol types, showing for example the main source regions and typical transport paths. Climatological studies of aerosol load at global and regional scales often rely on inferred aerosol type. There is still a high degree of inhomogeneity among satellite aerosol typing schemes, which makes the use different sensor datasets in a consistent way difficult. Knowledge of the 4d aerosol type distribution at these scales is essential for understanding the impact of different aerosol sources on climate, precipitation and air quality. All this information is needed for planning upcoming aerosol emissions policies. The exchange of expertise and the communication among satellite and ground-based measurement communities is fundamental for improving long-term dataset consistency, and for reducing aerosol type distribution uncertainties. Aerosol typing has been recognized as one of its high-priority activities of the AEROSAT (International Satellite Aerosol Science Network, http://aero-sat.org/) initiative. In the AEROSAT framework, a first critical review of aerosol typing procedures has been carried out. The review underlines the high heterogeneity in many aspects: approach, nomenclature, assumed number of components and parameters used for the

  18. Effects of Greenhouse Gas Increase and Stratospheric Ozone Depletion on Stratospheric Mean Age of Air in 1960-2010

    Science.gov (United States)

    Li, F.; Newman, P. A.; Pawson, S.; Perlwitz, J.

    2017-12-01

    The strength of the stratospheric Brewer-Dobson circulation (BDC) in a changing climate has been extensively studied, but the relative importance of greenhouse gas (GHG) increases and stratospheric ozone depletion in driving the BDC changes remains uncertain. This study separates the impacts of GHG and stratospheric ozone forcings on stratospheric mean age of air in the 1960-2010 period using the Goddard Earth Observing System Model (GEOS) Chemistry-Climate Model (CCM). The experiment compares a set of controlled simulations using a coupled atmosphere-ocean version of the GEOS CCM, in which either GHGs, or stratospheric ozone, or both factors evolve over time. The model results show that GHGs and stratospheric ozone have about equal contributions to the simulated mean age decrease. It is also found that GHG increases account for about two thirds of the enhanced strength of the lower stratospheric residual circulation. The results show that ozone depletion causes an increase in the mean age of air in the Antarctic summer lower stratosphere through two processes: 1) a seasonal delay in the Antarctic polar vortex breakup, that inhibits young mid-latitude air from mixing with the older air inside the vortex; and 2) enhanced Antarctic downwelling, that brings older air from middle and upper stratosphere into the lower stratosphere.

  19. The stratospheric ozone and the ozone layer

    International Nuclear Information System (INIS)

    Zea Mazo, Jorge Anibal; Leon Aristizabal Gloria Esperanza; Eslava Ramirez Jesus Antonio

    2000-01-01

    An overview is presented of the principal characteristics of the stratospheric ozone in the Earth's atmosphere, with particular emphasis on the tropics and the ozone hole over the poles. Some effects produced in the atmosphere as a consequence of the different human activities will be described, and some data on stratospheric ozone will be shown. We point out the existence of a nucleus of least ozone in the tropics, stretching from South America to central Africa, with annual mean values less than 240 DU, a value lower than in the middle latitudes and close to the mean values at the South Pole. The existence of such a minimum is confirmed by mean values from measurements made on satellites or with earthbound instruments, for different sectors in Colombia, like Medellin, Bogota and Leticia

  20. Effects of intense stratospheric ionisation events

    International Nuclear Information System (INIS)

    Reid, G.C.; McAfee, J.R.; Crutzen, P.J.

    1978-01-01

    High levels of ionising radiation in the Earth's stratosphere will lead to increased concentrations of nitrogen oxides and decreased concentrations of ozone. Changes in the surface environment will include an increased level, of biologically harmful UV radiation, caused by the ozone depletion, and a decreased level of visible solar radiation, due to the presence of major enhancements in the stratospheric concentration of nitrogen dioxide. These changes have been studied quantitatively, using the passage of the Solar System through a supernova remnant shell as an example. Some of the potential environmental changes are a substantial global cooling, abnormally dry conditions, a reduction in global photosynthesis and a large increase in the flux of atmospheric fixed nitrogen to the surface of the Earth. Such events might have been the cause of mass extinctions in the distant past. (Author)

  1. Stratospheric ozone: an introduction to its study

    International Nuclear Information System (INIS)

    Nicolet, M.

    1975-01-01

    An analysis is made of the various reactions in which ozone and atomic oxygen are involved in the stratosphere. At the present time, hydrogen, nitrogen, and chlorine compounds in the ranges parts per million, parts per billion, and parts per trillion may have significant chemical effects. In the upper stratosphere, above the ozone peak, where there is no strong departure from photochemical equilibrium conditions, the action of hydroxyl and hydroperoxyl radicals of nitrogen dioxide and chlorine monoxide on atomic oxygen and of atomic chlorine on ozone can be introduced. A precise determination of their exact effects requires knowledge of the vertical distribution of the H 2 O, CH 4 , and H 2 dissociation by reaction of these molecules with electronically excited oxygen atom O( 1 D); the ratio of the OH and HO 2 concentrations and their absolute values, which depend on insufficiently known rate coefficients; the various origins of nitric oxide production, with their vertical distributions related to latitude and season; and the various sources giving different chlorine compounds that may be dissociated in the stratosphere. In the lower stratosphere, below the ozone peak, there is no important photochemical production of O 3 , but there exist various possibilities of transport. The predictability of the action of chemical reactions depends strongly on important interactions between OH and HO 2 radicals with CO and NO, respectively, which affect the ratio n(OH)/n(HO 2 ) at the tropopause level; between OH and NO 2 , which lead to the formation of nitric acid with its downward transport toward the troposphere; between NO and HO 2 , which lead to NO 2 and its subsequent photodissociation; between ClO and NO, which also lead to NO 2 and become more important than the reaction of ClO with O; and between Cl and various molecules, such as CH 4 and H 2 , which lead to HCl with its downward transportation toward the troposphere

  2. Airborne Arctic Stratospheric Expedition II: An overview

    Science.gov (United States)

    Anderson, James G.; Toon, Owen B.

    1993-11-01

    The sudden onset of ozone depletion in the antarctic vortex set a precedent for both the time scale and the severity of global change. The Airborne Antarctic Ozone Experiment (AAOE), staged from Punta Arenas, Chile, in 1987, established that CFCs, halons, and methyl bromide, the dominant sources of chlorine and bromine radicals in the stratosphere, control the rate of ozone destruction over the Antarctic; that the vortex is depleted in reactive nitrogen and water vapor; and that diabatic cooling during the Antarctic winter leads to subsidence within the vortex core, importing air from higher altitudes and lower latitudes. This last conclusion is based on observed dramatic distortion in the tracer fields, most notably N2O.In 1989, the first Airborne Arctic Stratospheric Expedition (AASE-I), staged from Stavanger, Norway, and using the same aircraft employed for AAOE (the NASA ER-2 and the NASA DC-8), discovered that while NOx and to some degree NOy were perturbed within the arctic vortex, there was little evidence for desiccation. Under these (in contrast to the antarctic) marginally perturbed conditions, however, ClO was found to be dramatically enhanced such that a large fraction of the available (inorganic) chlorine resided in the form of ClO and its dimer ClOOCl.This leaves two abiding issues for the northern hemisphere and the mission of the second Airborne Arctic Stratospheric Expedition (AASE-II): (1) Will significant ozone erosion occur within the arctic vortex in the next ten years as chlorine loading in the stratosphere exceeds four parts per billion by volume? (2) Which mechanisms are responsible for the observed ozone erosion poleward of 30°N in the winter/spring northern hemisphere reported in satellite observations?

  3. Vertical sounding balloons for stratospheric photochemistry

    Science.gov (United States)

    Pommereau, J. P.

    The use of vertical sounding balloons for stratospheric photochemistry studies is illustrated by the use of a vertical piloted gas balloon for the search of NO2 diurnal variations. It is shown that the use of montgolfieres (hot air balloons) can enhance the vertical sounding technique. Particular attention is given to a sun-heated montgolfiere and to the more sophisticated infrared montgolfiere that is able to perform three to four vertical excursions per day and to remain aloft for weeks or months.

  4. Stratospheric chlorine: Blaming it on nature

    International Nuclear Information System (INIS)

    Taube, G.

    1993-01-01

    Much of the bitter public debate over ozone depletion has centered on the claim that chlorofluorocarbons (CFCs) pale into insignificance alongside natural sources of chlorine in the stratosphere. If so, goes the argument, chlorine could not be depleting ozone as atmospheric scientists claim, because the natural sources have been around since time immemorial, and the ozone layer is still there. The claim, put forward in a book by Rogelio Maduro and Ralf Schauerhammer, has since been touted by former Atomic Energy Commissioner Dixy Lee Ray and talk-show host Rush Limbaugh, and it forms the basis of much of the backlash now being felt by atmospheric scientists. The argument is simple: Maduro and Schauerhammer calculate that 600 million tons of chlorine enters the atmosphere annually from seawater, 36 million tons from volcanoes, 8.4 million tons from biomass burning, and 5 million tons from ocean biota. In contrast, CFCs account for a mere 750,000 tons of atmospheric chlorine a year. Besides disputing the numbers, scientists have both theoretical and observational bases for doubting that much of this chlorine is getting into the stratosphere, where it could affect the ozone layer. Linwood Callis of the National Aeronautics and Space Administration's (NASA) Langley Research Center points out one crucial problem with the argument: Chlorine from natural sources is soluble, and so it gets rained out of the lower atmosphere. CFCs, in contrast, are insoluble and inert and thus make it to the stratosphere to release their chlorine. What's more, observations of stratospheric chemistry don't support the idea that natural sources are contributing much to the chlorine there

  5. A Unified Satellite-Observation Polar Stratospheric Cloud (PSC) Database for Long-Term Climate-Change Studies

    Science.gov (United States)

    Fromm, Michael; Pitts, Michael; Alfred, Jerome

    2000-01-01

    This report summarizes the project team's activity and accomplishments during the period 12 February, 1999 - 12 February, 2000. The primary objective of this project was to create and test a generic algorithm for detecting polar stratospheric clouds (PSC), an algorithm that would permit creation of a unified, long term PSC database from a variety of solar occultation instruments that measure aerosol extinction near 1000 nm The second objective was to make a database of PSC observations and certain relevant related datasets. In this report we describe the algorithm, the data we are making available, and user access options. The remainder of this document provides the details of the algorithm and the database offering.

  6. The 'surf zone' in the stratosphere

    Science.gov (United States)

    McIntyre, M. E.; Palmer, T. N.

    Synoptic, coarse-grain, isentropic maps of Ertel's potential vorticity Q for the northern middle stratosphere, estimated using a large-Richardson-number approximation, are presented for a number of days in January-February 1979, together with some related isentropic trajectory calculations The effects of substituting FGGE for NMC base data are noted, as well as some slight corrections to maps published earlier. The combined evidence from the observations and from dynamical models strongly indicates the existence of planetary-wave breaking, a process in which material contours are rapidly and irreversibly deformed. In the winter stratosphere this occurs most spectacularly in a gigantic 'nonlinear critical layer', or 'surf zone', which surrounds the main polar vortex, and which tends to erode the vortex when wave amplitudes become large. Some of the FGGE-based Q maps suggest that we may be seeing glimpses of local dynamical instabilities and vortex-rollup phenomena within breaking planetary waves. Related phenomena in the troposphere are discussed. An objective definition of the area A( t) of the main vortex, as it appears on isentropic Q maps, is proposed. A smoothed time series of daily values of A( t) should be a statistically powerful 'circulation index' for the state of the winter-time middle stratosphere, which avoids the loss of information incurred by Eulerian space and time averaging.

  7. Effect of Sulfate Aerosol Geoengineering on Tropical cyclones

    Science.gov (United States)

    Wang, Q.; Moore, J.; Ji, D.

    2017-12-01

    Variation in tropical cyclone (TC) number and intensity is driven in part by changes in the thermodynamics that can be defined by ocean and atmospheric variables. Genesis Potential Index (GPI) and ventilation index (VI) are combinations of potential intensity, vertical wind shear, relative humidity, midlevel entropy deficit, and absolute vorticity that quantify thermodynamic forcing of TC activity under changed climates, and can be calculated from climate model output. Here we use five CMIP5 models running the RCP45 experiment the Geoengineering Model Intercomparison Project (GeoMIP) stratospheric aerosol injection G4 experiment to calculate the two indices over the 2020 to 2069 period. Globally, GPI under G4 is lower than under RCP45, though both have a slight increasing trend. Spatial patterns in the relative effectiveness of geoengineering show reductions in TC in all models in the North Atlantic basin, and northern Indian Ocean in all except NorESM1-M. In the North Pacific, most models also show relative reductions under G4. VI generally coincide with the GPI patterns. Most models project Potential intensity and Relative Humidity to be the dominant variable to affect genesis potential. Changes in vertical wind shear and vorticity are small with scatter across different models and ocean basins. We find that tropopause temperature maybe as important as sea surface temperature in effecting TC genesis. Thus stratospheric aerosol geoengineering impacts on potential intensity and hence TC intensity are reasonably consistent, but probably underestimated by statistical forecasts of Tropical North Atlantic hurricane activity driven by sea surface temperatures alone. However the impacts of geoengineering on other ocean basins are more difficult to assess, and require more complete understanding of their driving parameters under present day climates. Furthermore, the possible effects of stratospheric injection on chemical reactions in the stratosphere, such as ozone, are

  8. Stratospheric concentrations of N2O in July 1975

    International Nuclear Information System (INIS)

    Krey, P.W.; Lagomarsino, R.J.; Schonberg, M.

    1977-01-01

    The first measurement of the hemispheric distribution of N 2 O concentrations in the lower stratosphere of the Northern Hemisphere is reported for July 1975. This distribution is similar to those of CCl 3 F and SF 6 , although N 2 O is more stable in the stratosphere than either of the other trace gases. The inventory of N 2 O in the stratosphere of the Northern Hemisphere in July 1975 against which future observations can be compared is 136 Tg

  9. Extreme cosmos

    CERN Document Server

    Gaensler, Bryan

    2011-01-01

    The universe is all about extremes. Space has a temperature 270°C below freezing. Stars die in catastrophic supernova explosions a billion times brighter than the Sun. A black hole can generate 10 million trillion volts of electricity. And hypergiants are stars 2 billion kilometres across, larger than the orbit of Jupiter. Extreme Cosmos provides a stunning new view of the way the Universe works, seen through the lens of extremes: the fastest, hottest, heaviest, brightest, oldest, densest and even the loudest. This is an astronomy book that not only offers amazing facts and figures but also re

  10. Polar stratospheric cloud observations by MIPAS on ENVISAT: detection method, validation and analysis of the northern hemisphere winter 2002/2003

    Directory of Open Access Journals (Sweden)

    R. Spang

    2005-01-01

    Full Text Available The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS on ENVISAT has made extensive measurements of polar stratospheric clouds (PSCs in the northern hemisphere winter 2002/2003. A PSC detection method based on a ratio of radiances (the cloud index has been implemented for MIPAS and is validated in this study with respect to ground-based lidar and space borne occultation measurements. A very good correspondence in PSC sighting and cloud altitude between MIPAS detections and those of other instruments is found for cloud index values of less than four. Comparisons with data from the Stratospheric Aerosol and Gas Experiment (SAGE III are used to further show that the sensitivity of the MIPAS detection method for this threshold value of cloud index is approximately equivalent to an extinction limit of 10-3km-1 at 1022nm, a wavelength used by solar occultation experiments. The MIPAS cloud index data are subsequently used to examine, for the first time with any technique, the evolution of PSCs throughout the Arctic polar vortex up to a latitude close to 90° north on a near-daily basis. We find that the winter of 2002/2003 is characterised by three phases of very different PSC activity. First, an unusual, extremely cold phase in the first three weeks of December resulted in high PSC occurrence rates. This was followed by a second phase of only moderate PSC activity from 5-13 January, separated from the first phase by a minor warming event. Finally there was a third phase from February to the end of March where only sporadic and mostly weak PSC events took place. The composition of PSCs during the winter period has also been examined, exploiting in particular an infra-red spectral signature which is probably characteristic of NAT. The MIPAS observations show the presence of these particles on a number of occasions in December but very rarely in January. The PSC type differentiation from MIPAS indicates that future comparisons of PSC

  11. Millimeter wave spectroscopic measurements of stratospheric and mesospheric constituents over the Italian Alps: stratospheric ozone

    Directory of Open Access Journals (Sweden)

    V. Romaniello

    2007-06-01

    Full Text Available Measurements of rotational lines emitted by middle atmospheric trace gases have been carried out from the Alpine station of Testa Grigia (45.9°N, 7.7°E, elev. 3500 m by means of a Ground-Based Millimeter-wave Spectrometer (GBMS. Observations of species such as O3, HNO3, CO, N2O, HCN, and HDO took place during 4 winter periods, from February 2004 to March 2007, for a total of 116 days of measurements grouped in about 18 field campaigns. By studying the pressure-broadened shape of emission lines the vertical distribution of the observed constituents is retrieved within an altitude range of ?17-75 km, constrained by the 600 MHz pass band and the 65 kHz spectral resolution of the back-end spectrometer. This work discusses the behavior of stratospheric O3 during the entire period of operation at Testa Grigia. Mid-latitude O3 columnar content as estimated using GBMS measurements can vary by large amounts over a period of very few days, with the largest variations observed in December 2005, February 2006, and March 2006, confirming that the northern winter of 2005-2006 was characterized by a particularly intense planetary wave activity. The largest rapid variation from maximum to minimum O3 column values over Testa Grigia took place in December 2006 and reached a relative value of 72% with respect to the average column content for that period. During most GBMS observation times much of the variability is concentrated in the column below 20 km, with tropospheric weather systems and advection of tropical tropospheric air into the lower stratosphere over Testa Grigia having a large impact on the observed variations in column contents. Nonetheless, a wide variability is also found in middle stratospheric GBMS O3 measurements, as expected for mid-latitude ozone. We find that O3 mixing ratios at ?32 km are very well correlated with the solar illumination experienced by air masses over the previous ?15 days, showing that already at 32 km

  12. Environmental Temperature Effect on the Far-Infrared Absorption Features of Aromatic-Based Titan's Aerosol Analogs

    Science.gov (United States)

    Gautier, Thomas; Trainer, Melissa G.; Loeffler, Mark J.; Sebree, Joshua A.; Anderson, Carrie M.

    2016-01-01

    Benzene detection has been reported in Titans atmosphere both in the stratosphere at ppb levels by remote sensing and in the thermosphere at ppm levels by the Cassini's Ion and Neutral Mass Spectrometer. This detection supports the idea that aromatic and heteroaromatic reaction pathways may play an important role in Titans atmospheric chemistry, especially in the formation of aerosols. Indeed, aromatic molecules are easily dissociated by ultraviolet radiation and can therefore contribute significantly to aerosol formation. It has been shown recently that aerosol analogs produced from a gas mixture containing a low concentration of aromatic and/or heteroaromatic molecules (benzene, naphthalene, pyridine, quinoline and isoquinoline) have spectral signatures below 500/cm, a first step towards reproducing the aerosol spectral features observed by Cassini's Composite InfraRed Spectrometer (CIRS) in the far infrared. In this work we investigate the influence of environmental temperature on the absorption spectra of such aerosol samples, simulating the temperature range to which aerosols, once formed, are exposed during their transport through Titans stratosphere. Our results show that environmental temperature does not have any major effect on the spectral shape of these aerosol analogs in the far-infrared, which is consistent with the CIRS observations.

  13. AEROSOL AND GAS MEASUREMENT

    Science.gov (United States)

    Measurements provide fundamental information for evaluating and managing the impact of aerosols on air quality. Specific measurements of aerosol concentration and their physical and chemical properties are required by different users to meet different user-community needs. Befo...

  14. Facility of aerosol filtration

    Energy Technology Data Exchange (ETDEWEB)

    Duverger de Cuy, G; Regnier, J

    1975-04-18

    Said invention relates to a facility of aerosol filtration, particularly of sodium aerosols. Said facility is of special interest for fast reactors where sodium fires involve the possibility of high concentrations of sodium aerosols which soon clog up conventional filters. The facility intended for continuous operation, includes at the pre-filtering stage, means for increasing the size of the aerosol particles and separating clustered particles (cyclone separator).

  15. Can Aerosol Offset Urban Heat Island Effect?

    Science.gov (United States)

    Jin, M. S.; Shepherd, J. M.

    2009-12-01

    The Urban Heat Island effect (UHI) refers to urban skin or air temperature exceeding the temperatures in surrounding non-urban regions. In a warming climate, the UHI may intensify extreme heat waves and consequently cause significant health and energy problems. Aerosols reduce surface insolation via the direct effect, namely, scattering and absorbing sunlight in the atmosphere. Combining the National Aeronautics and Space Administration (NASA) AERONET (AErosol RObotic NETwork) observations over large cities together with Weather Research and Forecasting Model (WRF) simulations, we find that the aerosol direct reduction of surface insolation range from 40-100 Wm-2, depending on seasonality and aerosol loads. As a result, surface skin temperature can be reduced by 1-2C while 2-m surface air temperature by 0.5-1C. This study suggests that the aerosol direct effect is a competing mechanism for the urban heat island effect (UHI). More importantly, both aerosol and urban land cover effects must be adequately represented in meteorological and climate modeling systems in order to properly characterize urban surface energy budgets and UHI.

  16. Geo-Engineering Climate Change with Sulfate Aerosol

    Science.gov (United States)

    Rasch, P. J.; Crutzen, P. J.

    2006-12-01

    We explore the impact of injecting a precursor of sulfate aerosols into the middle atmosphere where they would act to increase the planetary albedo and thus counter some of the effects of greenhouse gase forcing. We use an atmospheric general circulation model (CAM, the Community Atmosphere Model) coupled to a slab ocean model for this study. Only physical effects are examined, that is we ignore the biogeochemical and chemical implications of changes to greenhouse gases and aerosols, and do not explore the important ethical, legal, and moral issues that are associated with deliberate geo-engineering efforts. The simulations suggest that the sulfate aerosol produced from the SO2 source in the stratosphere is sufficient to counterbalance most of the warming associated with the greenhouse gas forcing. Surface temperatures return to within a few tenths of a degree(K) of present day levels. Sea ice and precipitation distributions are also much closer to their present day values. The polar region surface temperatures remain 1-3 degrees warm in the winter hemisphere than present day values. This study is very preliminary. Only a subset of the relevant effects have been explored. The effect of such an injection of aerosols on middle atmospheric chemistry, and the effect on cirrus clouds are obvious missing components that merit scrutiny. There are probably others that should be considered. The injection of such aerosols cannot help in ameliorating the effects of CO2 changes on ocean PH, or other effects on the biogeochemistry of the earth system.

  17. Ultraviolet Studies of Jupiter's Hydrocarbons and Aerosols from Galileo

    Science.gov (United States)

    Gladstone, G. Randall

    2001-01-01

    This is the final report for this project. The purpose of this project was to support PI Wayne Pryor's effort to reduce and analyze Galileo UVS (Ultraviolet Spectrometer) data under the JSDAP program. The spectral observations made by the Galileo UVS were to be analyzed to determine mixing ratios for important hydrocarbon species (and aerosols) in Jupiter's stratosphere as a function of location on Jupiter. Much of this work is still ongoing. To date, we have concentrated on analyzing the variability of the auroral emissions rather than the absorption signatures of hydrocarbons, although we have done some work in this area with related HST-STIS data.

  18. Tropospheric aerosol backscatter background mode at CO2 wavelengths

    Science.gov (United States)

    Rothermel, Jeffry; Bowdle, David A.; Menzies, Robert T.; Post, Madison J.; Vaughan, J. Michael

    1989-01-01

    A comparison is made between three climatologies of backscatter measurements in the troposphere and lower stratosphere at CO2 wavelengths. These were obtained from several locations using ground-based and airborne lidar systems. All three measurement sets show similar features, specifically, a high frequency of occurrence of low backscatter over a limited range of values in the middle and upper atmosphere (the 'background mode'). This background mode is important for the design and performance simulation of the prospective satellite sensors that rely on atmospheric aerosols as scattering targets.

  19. Aerosols and Climate

    Indian Academy of Sciences (India)

    Large warming by elevated aerosols · AERONET – Global network (NASA) · Slide 25 · Slide 26 · Slide 27 · Slide 28 · Slide 29 · Slide 30 · Slide 31 · Long-term trends - Trivandrum · Enhanced warming over Himalayan-Gangetic region · Aerosol Radiative Forcing Over India _ Regional Aerosol Warming Experiment ...

  20. Aerosol measurements at 60 m during April 1994 remote cloud study intensive operating period (RCS/IOP)

    Energy Technology Data Exchange (ETDEWEB)

    Leifer, R.; Albert, B.; Lee, N.; Knuth, R.H. [Department of Energy, New York, NY (United States)] [and others

    1996-04-01

    Aerosol measurements were made at the Southern Great Plains Site of the Atmospheric Radiation Measurement (ARM) program. Many types of air masses pass over this area, and on the data acquisition day, extremly low aerosol scattering coefficients were seen. A major effort was placed on providing some characterization of the aerosol size distribution. Data is currently available from the experimental center.

  1. Hydration of the lower stratosphere by ice crystal geysers over land convective systems

    Directory of Open Access Journals (Sweden)

    S. Khaykin

    2009-03-01

    Full Text Available The possible impact of deep convective overshooting over land has been explored by six simultaneous soundings of water vapour, particles and ozone in the lower stratosphere next to Mesoscale Convective Systems (MCSs during the monsoon season over West Africa in Niamey, Niger in August 2006. The water vapour measurements were carried out using a fast response FLASH-B Lyman-alpha hygrometer. The high vertical resolution observations of the instrument show the presence of accumulation of enhanced water vapour layers between the tropopause at 370 K and the 420 K level. Most of these moist layers are shown connected with overshooting events occurring upwind as identified from satellite IR images over which the air mass probed by the sondes passed during the three previous days. In the case of a local overshoot identified by echo top turrets above the tropopause by the MIT C-band radar also in Niamey, tight coincidence was found between enhanced water vapour, ice crystal and ozone dip layers indicative of fast uplift of tropospheric air across the tropopause. The water vapour mixing ratio in the enriched layers exceeds frequently by 1–3 ppmv the average 6 ppmv saturation ratio at the tropopause and by up to 7 ppmv in the extreme case of local storm in coincidence with the presence of ice crystals. The presence of such layers strongly suggests hydration of the lower stratosphere by geyser-like injection of ice particles over overshooting turrets. The pile-like increase of water vapour up to 19 km seen by the high-resolution hygrometer during the season of maximum temperature of the tropopause, suggests that the above hydration mechanism may contribute to the summer maximum moisture in the lower stratosphere. If this interpretation is correct, hydration by ice geysers across the tropopause might be an important contributor to the stratospheric water vapour budget.

  2. Coupling in the middle atmosphere related to the 2013 major sudden stratospheric warming

    Directory of Open Access Journals (Sweden)

    R. J. de Wit

    2015-03-01

    Full Text Available The previously reported observation of anomalous eastward gravity wave forcing at mesopause heights around the onset of the January 2013 major sudden stratospheric warming (SSW over Trondheim, Norway (63° N, 10° E, is placed in a global perspective using Microwave Limb Sounder (MLS temperature observations from the Aura satellite. It is shown that this anomalous forcing results in a clear cooling over Trondheim about 10 km below mesopause heights. Conversely, near the mesopause itself, where the gravity wave forcing was measured, observations with meteor radar, OH airglow and MLS show no distinct cooling. Polar cap zonal mean temperatures show a similar vertical profile. Longitudinal variability in the high northern-latitude mesosphere and lower thermosphere (MLT is characterized by a quasi-stationary wave-1 structure, which reverses phase at altitudes below ~ 0.1 hPa. This wave-1 develops prior to the SSW onset, and starts to propagate westward at the SSW onset. The latitudinal pole-to-pole temperature structure associated with the major SSW shows a warming (cooling in the winter stratosphere (mesosphere which extends to about 40° N. In the stratosphere, a cooling extending over the equator and far into the summer hemisphere is observed, whereas in the mesosphere an equatorial warming is noted. In the Southern Hemisphere mesosphere, a warm anomaly overlaying a cold anomaly is present, which is shown to propagate downward in time. This observed structure is in accordance with the temperature perturbations predicted by the proposed interhemispheric coupling mechanism for cases of increased winter stratospheric planetary wave activity, of which major SSWs are an extreme case. These results provide observational evidence for the interhemispheric coupling mechanism, and for the wave-mean flow interaction believed to be responsible for the establishment of the anomalies in the summer hemisphere.

  3. A closer look at Arctic ozone loss and polar stratospheric clouds

    Directory of Open Access Journals (Sweden)

    N. R. P. Harris

    2010-09-01

    Full Text Available The empirical relationship found between column-integrated Arctic ozone loss and the potential volume of polar stratospheric clouds inferred from meteorological analyses is recalculated in a self-consistent manner using the ERA Interim reanalyses. The relationship is found to hold at different altitudes as well as in the column. The use of a PSC formation threshold based on temperature dependent cold aerosol formation makes little difference to the original, empirical relationship. Analysis of the photochemistry leading to the ozone loss shows that activation is limited by the photolysis of nitric acid. This step produces nitrogen dioxide which is converted to chlorine nitrate which in turn reacts with hydrogen chloride on any polar stratospheric clouds to form active chlorine. The rate-limiting step is the photolysis of nitric acid: this occurs at the same rate every year and so the interannual variation in the ozone loss is caused by the extent and persistence of the polar stratospheric clouds. In early spring the ozone loss rate increases as the solar insolation increases the photolysis of the chlorine monoxide dimer in the near ultraviolet. However the length of the ozone loss period is determined by the photolysis of nitric acid which also occurs in the near ultraviolet. As a result of these compensating effects, the amount of the ozone loss is principally limited by the extent of original activation rather than its timing. In addition a number of factors, including the vertical changes in pressure and total inorganic chlorine as well as denitrification and renitrification, offset each other. As a result the extent of original activation is the most important factor influencing ozone loss. These results indicate that relatively simple parameterisations of Arctic ozone loss could be developed for use in coupled chemistry climate models.

  4. The fate of atmospheric phosgene and the stratospheric chlorine loadings of its parent compounds: CCl4, C2Cl4, C2HCL3, CH3CCl3, and CHCl3

    Science.gov (United States)

    Kindler, T. P.; Chameides, W. L.; Wine, P. H.; Cunnold, D. M.; Alyea, F. N.; Franklin, J. A.

    1995-01-01

    of reaction of phosgene with sulfate aerosols. However, on the basis of the observed vertical distribution of COCl2, we estimate that the reaction of COCl2 with sulfate aerosol most likely has a gamma less than 5 x 10(exp -5) and, as a result, has a negligible impact on the stratospheric chlorine loadings of the phosgene parent compounds.

  5. New capability for ozone dial profiling measurements in the troposphere and lower stratosphere from aircraft

    Science.gov (United States)

    Hair, Johnathan; Hostetler, Chris; Cook, Anthony; Harper, David; Notari, Anthony; Fenn, Marta; Newchurch, Mike; Wang, Lihua; Kuang, Shi; Knepp, Travis; Burton, Sharon; Ferrare, Richard; Butler, Carolyn; Collins, Jim; Nehrir, Amin

    2018-04-01

    Recently, we successfully demonstrated a new compact and robust ozone DIAL lidar for smaller aircraft such as the NASA B200 and the ER-2 high-altitude aircraft. This is the first NASA airborne lidar to incorporate advanced solid-state lasers to produce the required power at the required ultraviolet wavelengths, and is compact and robust enough to operate nearly autonomously on the high-altitude ER-2 aircraft. This technology development resulted in the first new NASA airborne ozone DIAL instrument in more than 15 years. The combined ozone, aerosol, and clouds measurements provide valuable information on the chemistry, radiation, and dynamics of the atmosphere. In particular, from the ER-2 it offers a unique capability to study the upper troposphere and lower stratosphere.

  6. A condensed-mass advection based model for the simulation of liquid polar stratospheric clouds

    Directory of Open Access Journals (Sweden)

    D. Lowe

    2003-01-01

    Full Text Available We present a condensed-mass advection based model (MADVEC designed to simulate the condensation/evaporation of liquid polar stratospheric cloud (PSC particles. A (Eulerian-in-radius discretization scheme is used, making the model suitable for use in global or mesoscale chemistry and transport models (CTMs. The mass advection equations are solved using an adaption of the weighted average flux (WAF scheme. We validate the numerical scheme using an analytical solution for multicomponent aerosols. The physics of the model are tested using a test case designed by Meilinger et al. (1995. The results from this test corroborate the composition gradients across the size distribution under rapid cooling conditions that were reported in earlier studies.

  7. New capability for ozone dial profiling measurements in the troposphere and lower stratosphere from aircraft

    Directory of Open Access Journals (Sweden)

    Hair Johnathan

    2018-01-01

    Full Text Available Recently, we successfully demonstrated a new compact and robust ozone DIAL lidar for smaller aircraft such as the NASA B200 and the ER-2 high-altitude aircraft. This is the first NASA airborne lidar to incorporate advanced solid-state lasers to produce the required power at the required ultraviolet wavelengths, and is compact and robust enough to operate nearly autonomously on the high-altitude ER-2 aircraft. This technology development resulted in the first new NASA airborne ozone DIAL instrument in more than 15 years. The combined ozone, aerosol, and clouds measurements provide valuable information on the chemistry, radiation, and dynamics of the atmosphere. In particular, from the ER-2 it offers a unique capability to study the upper troposphere and lower stratosphere.

  8. CARIBIC observations of gaseous mercury in the upper troposphere and lower stratosphere

    Directory of Open Access Journals (Sweden)

    Slemr F.

    2013-04-01

    Full Text Available A unique set of gaseous mercury measurements in the upper troposphere and lower stratosphere (UT/LS has been obtained during the monthly CARIBIC (www.caribic-atmospheric.com flights since May 2005. The passenger Airbus 340-600 of Lufthansa covered routes to the Far East, North America, India, and the southern hemisphere. The accompanying measurements of CO, O3, NOy, H2O, aerosols, halocarbons, hydrocarbons, greenhouse gases, and several other parameters as well as backward trajectories enable a detailed analysis of these measurements. Speciation tests have shown that the CARIBIC measurements represent a good approximation of total gaseous mercury (TGM concentrations. Above the tropopause TGM always decrease with increasing potential vorticity (PV and O3 which implies its conversion to particle bound mercury. The observation of the lowest TGM concentrations at the highest particle concentrations in the stratosphere provides further evidence for such conversion. We will show how a seasonally dependent conversion rate could be derived using concomitantly measured SF6 mixing ratios as a timer. Tropospheric mercury data suggest the existence of a decreasing trend in the northern hemisphere whose size is comparable with the trend derived from long-term measurements by ship cruises, at Cape Point (South Africa and Mace Head (Ireland.

  9. The observation of nitric acid-containing particles in the tropical lower stratosphere

    Directory of Open Access Journals (Sweden)

    P. J. Popp

    2006-01-01

    Full Text Available Airborne in situ measurements over the eastern Pacific Ocean in January 2004 have revealed a new category of nitric acid (HNO3-containing particles in the tropical lower stratosphere. These particles are most likely composed of nitric acid trihydrate (NAT. They were intermittently observed in a narrow layer above the tropopause (18±0.1 km and over a broad geographic extent (>1100 km. In contrast to the background liquid sulfate aerosol, these particles are solid, much larger (1.7-4.7 µm vs. 0.1µm in diameter, and significantly less abundant (-4 cm-3 vs. 10 cm-3. Microphysical trajectory models suggest that the NAT particles grow over a 6-14 day period in supersaturated air that remains close to the tropical tropopause and might be a common feature in the tropics. The small number density of these particles implies a highly selective or slow nucleation process. Understanding the formation of solid NAT particles in the tropics could improve our understanding of stratospheric nucleation processes and, therefore, dehydration and denitrification.

  10. The 2009–2010 Arctic stratospheric winter – general evolution, mountain waves and predictability of an operational weather forecast model

    Directory of Open Access Journals (Sweden)

    A. Dörnbrack

    2012-04-01

    Full Text Available The relatively warm 2009–2010 Arctic winter was an exceptional one as the North Atlantic Oscillation index attained persistent extreme negative values. Here, selected aspects of the Arctic stratosphere during this winter inspired by the analysis of the international field experiment RECONCILE are presented. First of all, and as a kind of reference, the evolution of the polar vortex in its different phases is documented. Special emphasis is put on explaining the formation of the exceptionally cold vortex in mid winter after a sequence of stratospheric disturbances which were caused by upward propagating planetary waves. A major sudden stratospheric warming (SSW occurring near the end of January 2010 concluded the anomalous cold vortex period. Wave ice polar stratospheric clouds were frequently observed by spaceborne remote-sensing instruments over the Arctic during the cold period in January 2010. Here, one such case observed over Greenland is analysed in more detail and an attempt is made to correlate flow information of an operational numerical weather prediction model to the magnitude of the mountain-wave induced temperature fluctuations. Finally, it is shown that the forecasts of the ECMWF ensemble prediction system for the onset of the major SSW were very skilful and the ensemble spread was very small. However, the ensemble spread increased dramatically after the major SSW, displaying the strong non-linearity and internal variability involved in the SSW event.

  11. Presence of PAH or HAC below 900 km in the Titan's stratosphere?

    Science.gov (United States)

    Cordier, Daniel; COURS, Thibaud; Rey, Michael; Maltagliati, Luca; Seignovert, Benoit; Biennier, Ludovic

    2016-10-01

    In 2006, during Cassini's 10th flyby of Titan (T10), Bellucci et al. (2009) observed a solar occultation by Titan's atmosphere through the solar port of the Cassini/VIMS instrument. These authors noticed the existence of an unexplained additional absorption superimposed to the CH4 3.3 microns band. Because they were unable to model this absorption with gases, they attributed this intriguing feature to the signature of solid state organic components. Kim et al. (2011) revisited the data collected by Bellucci et al. (2009) and they considered the possible contribution of aerosols formed by hydrocarbon ices. They specifically took into account C2H6, CH4, CH3CN, C5H12 and C6H12 ices. More recently, Maltagliati et al. (2015) analyzed a set of four VIMS solar occultations, corresponding to flybys performed between January 2006 and September 2011 at different latitudes. They confirmed the presence of the 3.3 µm absorption in all occultations and underlined the possible importance of gaseous ethane, which has a strong plateau of absorption lines in that wavelength range. In this work, we show that neither hydrocarbon ices nor molecular C2H6 cannot satisfactorily explain the observed absorption. Our simulations speak in favor of an absorption due to the presence of PAH molecules or HAC in the stratosphere of Titan. PAH have been already considered by Lopes-Puertas et al. (2013) at altitudes larger than ~900 km and tentatively identified in the stratosphere by Maltagliati et al. (2015); PAH and HAC are good candidates for Titan's aerosols precursors.

  12. The Limb Infrared Monitor of the Stratosphere (LIMS) experiment

    Science.gov (United States)

    Russell, J. M.; Gille, J. C.

    1978-01-01

    The Limb Infrared Monitor of the Stratosphere is used to obtain vertical profiles and maps of temperature and the concentration of ozone, water vapor, nitrogen dioxide, and nitric acid for the region of the stratosphere bounded by the upper troposphere and the lower mesosphere.

  13. Stratospheric ozone, ultraviolet radiation and climate change

    International Nuclear Information System (INIS)

    Boucher, O.

    2008-01-01

    It is well known that an overexposure to ultraviolet radiation is associated with a number of health risks such as an increased risk of cataracts and skin cancers. At a time when climate change is often blamed for all our environmental problems, what is the latest news about the stratospheric ozone layer and other factors controlling ultraviolet radiation at the surface of the Earth? Will the expected changes in the chemical composition of the atmosphere and changes in our climate increase or decrease the risk for skin cancer? This article investigates the role of the various factors influencing ultraviolet radiation and presents the latest knowledge on the subject. (author)

  14. Photochemistry of materials in the stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, H.S. [Lawrence Berkeley Laboratories, CA (United States)

    1993-12-01

    This research is concerned with global change in the atmosphere, including photochemical modeling and, in the past, experimental gas-phase photochemistry involving molecular dynamics and laboratory study of atmospheric chemical reactions. The experimental work on this project concluded in August 1991, but there is a back-log of several journal articles to be written and submitted for publication. The theoretical work involves photochemical modeling in collaboration with Lawrence Livermore National Laboratory (LLNL) and advising the Upper Atmosphere Research Program on Atmospheric Effects of Stratospheric Aircraft, National Aeronautics and Space Administration (NASA).

  15. Studying Stratospheric Temperature Variation with Cosmic Ray Measurements

    Science.gov (United States)

    Zhang, Xiaohang; He, Xiaochun

    2015-04-01

    The long term stratospheric cooling in recent decades is believed to be equally important as surface warming as evidence of influences of human activities on the climate system. Un- fortunatly, there are some discrepancies among different measurements of stratospheric tem- peratures, which could be partially caused by the limitations of the measurement techniques. It has been known for decades that cosmic ray muon flux is sensitive to stratospheric temperature change. Dorman proposed that this effect could be used to probe the tempera- ture variations in the stratophere. In this talk, a method for reconstructing stratospheric temperature will be discussed. We verify this method by comparing the stratospheric tem- perature measured by radiosonde with the ones derived from cosmic ray measurement at multiple locations around the globe.

  16. Stratospheric Temperature Trends Observed by TIMED/SABER

    Science.gov (United States)

    Xian, T.; Tan, R.

    2017-12-01

    Trends in the stratospheric temperature are studied based on the temperature profile observation from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER). The spatially trends are evaluated in different time scales ranging from decadal to monthly resolved. The results indicate a signature of BDC acceleration. There are strong warming trends (up to 9 K/decade) in the middle to upper stratosphere in the high latitude spring, summer, and autumn seasons, accompanied by strong cooling trends in the lower stratosphere. Besides, strong warming trends occurs through the whole stratosphere over the Southern Hemisphere, which confirms Antarctic ozone layer healing since 2000. In addition, the results demonstrate a significant warming trends in the middle of tropical stratosphere, which becomes strongest during June-July-August.

  17. Stratospheric ozone - Impact of human activity

    Science.gov (United States)

    Mcelroy, Michael B.; Salawitch, Ross J.

    1989-01-01

    The current knowledge of the chemistry of the stratosphere is reviewed, with particular consideration given to the measurements from the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment and from the Airborne Antarctic Ozone Experiment. Analysis of the ATMOS data at 30 deg N suggests that the current understanding of the contemporary-stratosphere chemistry at mid-latitudes is relatively complete, except for possible problems with the diurnal variations of N2O5 at low altitudes, and with ClNO3 at higher altitudes. Except for some difficulties with these two compounds, the data from ATMOS agree well with the gas phase models for nitrogen and chlorine species at 30 deg N in spring. It is emphasized that, in addition to the HOCl mechanism proposed by Solomon et al. (1986), the ClO-BrO scheme proposed by McElroy et al. (1986), and the ClO dimer mechanism introduced by Molina and Molina (1987), other processes exist that are responsible for ozone removal.

  18. Sub-micrometer scale minor element mapping in interplanetary dust particles: a test for stratospheric contamination

    International Nuclear Information System (INIS)

    Flynn, G.J.; Keller, L.P.; Sutton, S.R.

    2006-01-01

    We mapped the spatial distribution of minor elements including K, Mn, and Zn in 3 IDPs and found no evidence for the surface coatings (rims) of these elements that would be expected if the enrichments previously reported were due to contamination. Combined X-ray microprobe (XRM), energy dispersive x-ray fluorescence using a Transmission Electron Microscope (TEM), and electron microprobe measurements have determined that the average bulk chemical composition of the interplanetary dust particles (IDPs) collected from the Earth's stratosphere is enriched relative to the CI meteorite composition by a factor of 2 to 4 for carbon and for the moderately volatile elements Na, K, P, Mn, Cu, Zn, Ga, Ge, and Se, and enriched to ∼30 times CI for Br. However, Jessberger et al., who have reported similar bulk enrichments using Proton Induced X-ray Emission (PIXE), attribute the enrichments to contamination by meteor-derived atmospheric aerosols during the several weeks these IDPs reside in the Earth's atmosphere prior to collection. Using scanning Auger spectroscopy, a very sensitive surface analysis technique, Mackinnon and Mogk have observed S contamination on the surface of IDPs, presumably due to the accretion of sulfate aerosols during stratospheric residence. But the S-rich layer they detected was so thin (∼100 angstroms thick) that the total amount of S on the surface was too small to significantly perturb the bulk S-content of a chondritic IDP. Stephan et al. provide support for the contamination hypothesis by reporting the enrichment of Br on the edges of the IDPs using Time-of-Flight Secondary-Ion Mass-Spectrometry (TOF-SIMS), but TOF-SIMS is notorious for producing false edge-effects, particularly on irregularly-shaped samples like IDPs. Sutton et al. mapped the spatial distribution of Fe, Ni, Zn, Br, and Sr, at the ∼2 (micro)m scale, in four IDPs using element-specific x-ray fluorescence (XRF) computed microtomography. They found the moderately volatile

  19. Balance of the tropospheric ozone and its relation to stratospheric intrusions indicated by cosmogenic radionuclides. Technical progress report, November 1, 1980-June 30, 1981

    International Nuclear Information System (INIS)

    Reiter, R.; Kanter, H.J.; Sladkovic, R.; Jaeger, H.; Munzert, K.H.

    1981-06-01

    The balance of the tropospheric ozone is studied with regard to sources and sinks. The influx of stratospheric ozone through stratospheric intrusions and photochemical production under pure air conditions is discussed. The 4-year measuring series (1977-1980) of the ozone concentration measured at 3 different levels are evaluated, the influence of meteorological parameters is examined. The time variation of the ozone layer between 1000 and 3000 m ASL is investigated as a function of different ozone sources. First results show that stratospheric ozone arriving at the troposphere penetrates only in a few rare cases to the ground layer below 1500 m ASL. Most of the time, the variation of ozone concentration in this layer is determined by photochemical processes which are, in turn, controlled by meteorological parameters. The upper boundary of the photochemically active layer is found at about 500 m above ground. Variability of the concentration of stratospheric aerosol and its optical properties after the volcanic eruptions in the year 1980 are discussed on the basis on lidar backscattering measurements

  20. Balance of the tropospheric ozone and its relation to stratospheric intrusions indicated by cosmogenic radionuclides. Technical progress report, 1 November 1978-30 June 1979

    International Nuclear Information System (INIS)

    Reiter, R.; Kanter, H.J.; Poetzl, K.; Sladkovic, R.; Jaeger, H.; Mueller, H.

    The balance of the tropospheric ozone as a function of atmospheric pollutants, tropospheric transport, and stratospheric intrusions is under active investigation. Continuous recordings of the ozone concentration at three levels (3000 m, 1800 m, and 700 m a.s.l.) and of the cosmogenic radionuclides Be 7 , P 32 , P 33 , and the CO 2 are available and used for subject purposes. Results of a statistical evaluation concerning the frequency of high concentrations (> 70 ppB) of the tropospheric ozone are presented and possible sources discussed. Observations of changes in the fine structure of the ozone profile in the lower stratosphere after solar events are shown by balloon-borne ozone soundings up to 35 km altitude and discussed in connection with parameters of the stratospheric-tropospheric exchange. Monitoring of the stratospheric aerosol layer by lidar was continued. The accuracy of these measurements was considerably enhanced by significant system improvements. Intercomparisons with the results of nearby Dobson stations allowed conclusions to be drawn on the suitability of a filter spectrophotometer for the determination of the total ozone. Solar-terrestrial relationships were investigated and are discussed

  1. Chemical and climatic drivers of radiative forcing due to changes in stratospheric and tropospheric ozone over the 21st century

    Science.gov (United States)

    Banerjee, Antara; Maycock, Amanda C.; Pyle, John A.

    2018-02-01

    The ozone radiative forcings (RFs) resulting from projected changes in climate, ozone-depleting substances (ODSs), non-methane ozone precursor emissions and methane between the years 2000 and 2100 are calculated using simulations from the UM-UKCA chemistry-climate model (UK Met Office's Unified Model containing the United Kingdom Chemistry and Aerosols sub-model). Projected measures to improve air-quality through reductions in non-methane tropospheric ozone precursor emissions present a co-benefit for climate, with a net global mean ozone RF of -0.09 W m-2. This is opposed by a positive ozone RF of 0.05 W m-2 due to future decreases in ODSs, which is driven by an increase in tropospheric ozone through stratosphere-to-troposphere transport of air containing higher ozone amounts. An increase in methane abundance by more than a factor of 2 (as projected by the RCP8.5 scenario) is found to drive an ozone RF of 0.18 W m-2, which would greatly outweigh the climate benefits of non-methane tropospheric ozone precursor reductions. A small fraction (˜ 15 %) of the ozone RF due to the projected increase in methane results from increases in stratospheric ozone. The sign of the ozone RF due to future changes in climate (including the radiative effects of greenhouse gases, sea surface temperatures and sea ice changes) is shown to be dependent on the greenhouse gas emissions pathway, with a positive RF (0.05 W m-2) for RCP4.5 and a negative RF (-0.07 W m-2) for the RCP8.5 scenario. This dependence arises mainly from differences in the contribution to RF from stratospheric ozone changes. Considering the increases in tropopause height under climate change causes only small differences (≤ |0.02| W m-2) for the stratospheric, tropospheric and whole-atmosphere RFs.

  2. Cosmogenic 35S as a Novel Detector of Stratospheric Air at the Earth's Surface: Key Findings from the Western United States and New Insights into the Seasonal Variations of Ozone and Sulfate in East Asia

    Science.gov (United States)

    Lin, M.; Thiemens, M. H.; Shaheen, R.; Biglari, S.; Crocker, D.; Zhang, Z.; Tao, J.; Su, L.; Fung, J. C. H.; Su, B.; Liu, L.

    2016-12-01

    The extent to which stratospheric intrusions on synoptic scales influence the tropospheric ozone (O3) levels remains poorly understood because quantitative detection of stratosphere air at the Earth's surface has been challenging. Cosmogenic 35S is invaluable in such quantification, but this has not yet been unambiguously demonstrated. As a global hot spot for stratospheric intrusions, the western United States (US) is a natural laboratory for testing the validity of this approach. Here, we present measurements of 35S in sulfate aerosols during a well-defined deep stratospheric intrusion event in the western US, which led to a regional O3 pollution event across southern California. The surprisingly high 35S activity in this episode is greater than any other natural radiogenic sulfate aerosols reported in the literature, providing the first and direct field-based evidence that 35S is a sensitive tracer for air mass of stratospheric origin and transported downward. Using this novel tracer, we quantify the seasonal variation for the strength of downward transport of stratospheric air to the planetary boundary layer in East Asia (EA) and what it may mean for surface O3 and sulfate levels. Our 35S measurements in sulfate aerosols collected from a background site (Mount Wuyi; 27.72°N, 117.68°E) during 2014-2015 show peaks in spring and autumn and the temporal variations of 35S were in tandem with surface O3 levels. These results imply that stratospheric O3 in aged stratospheric air masses may contribute to surface O3 levels in the study region in these two seasons. Along with radiogenic 35S analysis, measuring all seven stable isotopes (16O, 17O, 18O, 32S, 33S, 34S and 36S) in the same sulfate samples provides significantly deeper understanding of the atmospheric sulfur cycle in this region. Triple oxygen isotopes are being measured and preliminary results show that the relative importance of different formation pathways of secondary sulfate in EA is likely altitude

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  5. STRATAQ: A three-dimensional Chemical Transport Model of the stratosphere

    Directory of Open Access Journals (Sweden)

    B. Grassi

    2002-06-01

    Full Text Available A three-dimensional (3-D Chemical Transport Model (CTM of the stratosphere has been developed and used for a test study of the evolution of chemical species in the arctic lower stratosphere during winter 1996/97. This particular winter has been chosen for testing the model’s capabilities for its remarkable dynamical situation (very cold and strong polar vortex along with the availability of sparse chlorine, HNO3 and O3 data, showing also very low O3 values in late March/April. Due to those unusual features, the winter 1996/97 can be considered an excellent example of the impact of both dynamics and heterogeneous reactions on the chemistry of the stratosphere. Model integration has been performed from January to March 1997 and the resulting long-lived and short-lived tracer fields compared with available measurements. The model includes a detailed gas phase chemical scheme and a parameterization of the heterogeneous reactions occurring on liquid aerosol and polar stratospheric cloud (PSC surfaces. The transport is calculated using a semi-lagrangian flux scheme, forced by meteorological analyses. In such form, the STRATAQ CTM model is suitable for short-term integrations to study transport and chemical evolution related to "real" meteorological situations. Model simulation during the chosen winter shows intense PSC formation, with noticeable local HNO3 capture by PSCs, and the activation of vortex air leading to chlorine production and subsequent O3 destruction. The resulting model fields show generally good agreement with satellite data (MLS and TOMS, although the available observations, due to their limited number and time/space sparse nature, are not enough to effectively constraint the model. In particular, the model seems to perform well in reproducing the rapid processing of air inside the polar vortex on PSC converting reservoir species in active chlorine. In addition, it satisfactorily reproduces the morphology of the continuous O3

  6. STRATAQ: A three-dimensional Chemical Transport Model of the stratosphere

    Directory of Open Access Journals (Sweden)

    B. Grassi

    Full Text Available A three-dimensional (3-D Chemical Transport Model (CTM of the stratosphere has been developed and used for a test study of the evolution of chemical species in the arctic lower stratosphere during winter 1996/97. This particular winter has been chosen for testing the model’s capabilities for its remarkable dynamical situation (very cold and strong polar vortex along with the availability of sparse chlorine, HNO3 and O3 data, showing also very low O3 values in late March/April. Due to those unusual features, the winter 1996/97 can be considered an excellent example of the impact of both dynamics and heterogeneous reactions on the chemistry of the stratosphere. Model integration has been performed from January to March 1997 and the resulting long-lived and short-lived tracer fields compared with available measurements. The model includes a detailed gas phase chemical scheme and a parameterization of the heterogeneous reactions occurring on liquid aerosol and polar stratospheric cloud (PSC surfaces. The transport is calculated using a semi-lagrangian flux scheme, forced by meteorological analyses. In such form, the STRATAQ CTM model is suitable for short-term integrations to study transport and chemical evolution related to "real" meteorological situations. Model simulation during the chosen winter shows intense PSC formation, with noticeable local HNO3 capture by PSCs, and the activation of vortex air leading to chlorine production and subsequent O3 destruction. The resulting model fields show generally good agreement with satellite data (MLS and TOMS, although the available observations, due to their limited number and time/space sparse nature, are not enough to effectively constraint the model. In particular, the model seems to perform well in reproducing the rapid processing of air inside the polar vortex on PSC converting reservoir species in active chlorine. In addition, it

  7. Imaging gravity waves in lower stratospheric AMSU-A radiances, Part 2: Validation case study

    Directory of Open Access Journals (Sweden)

    S. D. Eckermann

    2006-01-01

    Full Text Available Two-dimensional radiance maps from Channel 9 (~60–90 hPa of the Advanced Microwave Sounding Unit (AMSU-A, acquired over southern Scandinavia on 14 January 2003, show plane-wave-like oscillations with a wavelength λh of ~400–500 km and peak brightness temperature amplitudes of up to 0.9 K. The wave-like pattern is observed in AMSU-A radiances from 8 overpasses of this region by 4 different satellites, revealing a growth in the disturbance amplitude from 00:00 UTC to 12:00 UTC and a change in its horizontal structure between 12:00 UTC and 20:00 UTC. Forecast and hindcast runs for 14 January 2003 using high-resolution global and regional numerical weather prediction (NWP models generate a lower stratospheric mountain wave over southern Scandinavia with peak 90 hPa temperature amplitudes of ~5–7 K at 12:00 UTC and a similar horizontal wavelength, packet width, phase structure and time evolution to the disturbance observed in AMSU-A radiances. The wave's vertical wavelength is ~12 km. These NWP fields are validated against radiosonde wind and temperature profiles and airborne lidar profiles of temperature and aerosol backscatter ratios acquired from the NASA DC-8 during the second SAGE III Ozone Loss and Validation Experiment (SOLVE II. Both the amplitude and phase of the stratospheric mountain wave in the various NWP fields agree well with localized perturbation features in these suborbital measurements. In particular, we show that this wave formed the type II polar stratospheric clouds measured by the DC-8 lidar. To compare directly with the AMSU-A data, we convert these validated NWP temperature fields into swath-scanned brightness temperatures using three-dimensional Channel 9 weighting functions and the actual AMSU-A scan patterns from each of the 8 overpasses of this region. These NWP-based brightness temperatures contain two-dimensional oscillations due to this resolved stratospheric mountain wave that have an amplitude, wavelength

  8. Characterizing the Asian Tropopause Aerosol Layer (ATAL) Using Satellite Observations, Balloon Measurements and a Chemical Transport Model

    Science.gov (United States)

    Fairlie, T. D.; Vernier, J.-P.; Liu, H.; Deshler, T.; Natarajan, M.; Bedka, K.; Wegner, T.; Baker, N.; Gadhavi, H.; Ratnam, M. V.; hide

    2016-01-01

    Satellite observations and numerical modeling studies have demonstrated that the Asian Summer Monsoon (ASM) provide a conduit for gas-phase pollutants in south Asia to reach the lower stratosphere. Now, observations from the CALIPSO satellite have revealed the Asian Tropopause Aerosol Layer (ATAL), a summertime accumulation of aerosols in the upper troposphere and lower stratosphere (UTLS), associated with the ASM anticyclone. The ATAL has potential implications for regional cloud properties, climate, and chemical processes in the UTLS. Here, we show in situ measurements from balloon-borne instruments, aircraft, and satellite observations, together with trajectory and chemical transport model (CTM) simulations to explore the origin, composition, physical, and optical properties of aerosols in the ATAL. In particular, we show balloon-data from our BATAL-2015 field campaign to India and Saudi Arabia in summer 2015, which includes in situ backscatter measurements from COBALD instruments, and the first observations of size and volatility of aerosols in the ATAL layer using optical particle counters (OPCs). Back trajectory calculations initialized from CALIPSO observations point to deep convection over North India as a principal source of ATAL aerosols. Available aircraft observations suggest significant sulfur and carbonaceous components to the ATAL, which is supported by simulations using the GEOS-Chem CTM. Source elimination studies conducted with the GEOS-Chem indicate that ATAL aerosols originate primary from south Asian sources, in contrast with some earlier studies.

  9. Pollution metallique relargable par les aerosols d'origine autoroutiere

    OpenAIRE

    Lebreton , Laurent; Thevenot , Daniel ,

    1992-01-01

    International audience; Because they are highly contaminated by heavy metals, road aerosols may pollute runoff waters. To estimate the mobility of some toxic metals such as Zn, Pb or Cd, these aerosols have been submited to a range of sequential chemical extraction (chemical speciation) and to laboratory release experiments. Both chemical speciation and reactor experiments show similar metal behaviour. Zn and Cd are extremely mobile (60 % released) while Pb, highly bound to particles, needs a...

  10. Dynamical response of the Arctic winter stratosphere to global warming

    Science.gov (United States)

    Karpechko, A.; Manzini, E.

    2017-12-01

    Climate models often simulate dynamical warming of the Arctic stratosphere as a response to global warming in association with a strengthening of the deep branch of the Brewer-Dobson circulation; however until now, no satisfactory mechanism for such a response has been suggested. Here we investigate the role of stationary planetary waves in the dynamical response of the Arctic winter stratosphere circulation to global warming by analysing simulations performed with atmosphere-only Coupled Model Intercomparison Project Phase 5 (CMIP5) models driven by prescribed sea surface temperatures (SSTs). We focus on December-February (DJF) because this is the period when the troposphere and stratosphere are strongly coupled. When forced by increased SSTs, all the models analysed here simulate Arctic stratosphere dynamical warming, mostly due to increased upward propagation of quasi-stationary wave number 1, as diagnosed by the meridional eddy heat flux. By analysing intermodel spread in the response we show that the stratospheric warming and increased wave flux to the stratosphere correlate with the strengthening of the zonal winds in subtropics and mid-latitudes near the tropopause- a robust response to global warming. These results support previous studies of future Arctic stratosphere changes and suggest a dynamical warming of the Arctic wintertime polar vortex as the most likely response to global warming.

  11. Radiative and Dynamical Feedbacks Limit the Climate Response to Extremely Large Volcanic Eruptions

    Science.gov (United States)

    Wade, D. C.; Vidal, C. M.; Keeble, J. M.; Griffiths, P. T.; Archibald, A. T.

    2017-12-01

    Explosive volcanic eruptions are a major cause of chemical and climatic perturbations to the atmosphere, injecting chemically and radiatively active species such as sulfur dioxide (SO2) into the stratosphere. The rate determining step for sulfate aerosol production is SO2 + OH +M → HSO3 +M. This means that chemical feedbacks on the hydroxyl radical, OH, can modulate the production rate of sulfate aerosol and hence the climate effects of large volcanic eruptions. Radiative feedbacks due to aerosols, ozone and sulfur dioxide and subsequent dynamical changes also affect the evolution of the aerosol cloud. Here we assess the role of radiative and chemical feedbacks on sulfate aerosol production using UM-UKCA, a chemistry-climate model coupled to GLOMAP, a prognostic modal aerosol model. A 200 Tg (10x Pinatubo) emission scenario is investigated. Accounting for radiative feedbacks, the SO2 lifetime is 55 days compared to 26 days in the baseline 20 Tg (1x Pinatubo) simulation. By contrast, if all radiative feedbacks are neglected the lifetime is 73 days. Including radiative feedbacks reduces the SO2 lifetime: heating of the lower stratosphere by aerosol increases upwelling and increases transport of water vapour across the tropopause, increasing OH concentrations. The maximum effective radius of the aerosol particles increases from 1.09 µm to 1.34 µm as the production of aerosol is quicker. Larger and fewer aerosol particles are produced which are less effective at scattering shortwave radiation and will more quickly sediment from the stratosphere. As a result, the resulting climate cooling by the eruption will be less strong when accounting for these radiative feedbacks. We illustrate the consequences of these effects for the 1257 Samalas eruption, the largest common era volcanic eruption, using UM-UKCA in a coupled atmosphere-ocean configuration. As a potentially halogen rich eruption, we investigate the differing ozone response to halogen-rich and halogen

  12. Antarctic aerosols - A review

    Science.gov (United States)

    Shaw, Glenn E.

    1988-02-01

    Tropospheric aerosols with the diameter range of half a micron reside in the atmosphere for tens of days and teleconnect Antarctica with other regions by transport that reaches planetary scales of distances; thus, the aerosol on the Antarctic ice represents 'memory modules' of events that took place at regions separated from Antarctica by tens of thousands of kilometers. In terms of aerosol mass, the aerosol species include insoluble crustal products (less than 5 percent), transported sea-salt residues (highly variable but averaging about 10 percent), Ni-rich meteoric material, and anomalously enriched material with an unknown origin. Most (70-90 percent by mass) of the aerosol over the Antarctic ice shield, however, is the 'natural acid sulfate aerosol', apparently deriving from biological processes taking place in the surrounding oceans.

  13. CERN: Antiprotons probe the nuclear stratosphere

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The outer periphery of heavy stable nuclei is notoriously difficult to study experimentally. While the well understood electromagnetic interaction between electrons (or muons) and protons has given the nuclear charge (or proton) distribution with high precision for almost all stable nuclei, neutron distribution studies are much less precise. This is especially true for large nuclear distances, where the nuclear density is small. A few previous experiments probing the nuclear ''stratosphere'' suggested that far from the centre of the nucleus (of the order of 2 nuclear radii) this stratosphere may be composed predominantly of neutrons. At the end of the sixties the term ''neutron halo'' was introduced to describe this phenomenon, but experimental evidence was scarce or even controversial, and remained so for almost a quarter of a century. Recently, the Warsaw/Munich/Berlin collaboration working within the PS203 experiment at CERN's LEAR low energy antiproton ring, proposed a new method to study the nuclear periphery using stopped antiprotons. The halo now looks firmer. A 200 MeV/c beam of antiprotons was slowed down by interactions with atomic electrons. When antiproton kinetic energy drops well below 1 keV, the particles are captured in the outermost orbits of ''exotic atoms'', where the antiprotons take the place of the usual orbital electrons. With the lower orbits in this antiprotonic atom empty, the antiproton drops toward the nuclear surface, first emitting Auger electrons and later predominantly antiprotonic X-rays. Due to the strong interaction between antiprotons and nucleons, the antiproton succumbs to annihilation with a nucleon in the rarified nuclear stratosphere, far above the innermost Bohr orbit of the atom. The annihilation probability in heavy nuclei is maximal where the nuclear density is about 3% of its central value and extends to densities many orders of magnitude smaller

  14. CERN: Antiprotons probe the nuclear stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-06-15

    The outer periphery of heavy stable nuclei is notoriously difficult to study experimentally. While the well understood electromagnetic interaction between electrons (or muons) and protons has given the nuclear charge (or proton) distribution with high precision for almost all stable nuclei, neutron distribution studies are much less precise. This is especially true for large nuclear distances, where the nuclear density is small. A few previous experiments probing the nuclear ''stratosphere'' suggested that far from the centre of the nucleus (of the order of 2 nuclear radii) this stratosphere may be composed predominantly of neutrons. At the end of the sixties the term ''neutron halo'' was introduced to describe this phenomenon, but experimental evidence was scarce or even controversial, and remained so for almost a quarter of a century. Recently, the Warsaw/Munich/Berlin collaboration working within the PS203 experiment at CERN's LEAR low energy antiproton ring, proposed a new method to study the nuclear periphery using stopped antiprotons. The halo now looks firmer. A 200 MeV/c beam of antiprotons was slowed down by interactions with atomic electrons. When antiproton kinetic energy drops well below 1 keV, the particles are captured in the outermost orbits of ''exotic atoms'', where the antiprotons take the place of the usual orbital electrons. With the lower orbits in this antiprotonic atom empty, the antiproton drops toward the nuclear surface, first emitting Auger electrons and later predominantly antiprotonic X-rays. Due to the strong interaction between antiprotons and nucleons, the antiproton succumbs to annihilation with a nucleon in the rarified nuclear stratosphere, far above the innermost Bohr orbit of the atom. The annihilation probability in heavy nuclei is maximal where the nuclear density is about 3% of its central value and extends to densities many orders of magnitude smaller. Antiproton annihilation on a proton or on a neutron at the nuclear

  15. Radioactive aerosols. [In Russian

    Energy Technology Data Exchange (ETDEWEB)

    Natanson, G L

    1956-01-01

    Tabulations are given presenting various published data on safe atmospheric concentrations of various radioactive and non-radioactive aerosols. Methods of determination of active aerosol concentrations and dispersion as well as the technical applications of labeled aerosols are discussed. The effect of atomic explosions are analyzed considering the nominal atomic bomb based on /sup 235/U and /sup 232/Pu equivalent to 20,000 tons of TNT.

  16. Aerosols CFA 97

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    During the thirteen congress on aerosols several papers were presented about the behaviour of radioactive aerosols and their impact on environment, or the exposure to radon and to its daughters, the measurement of the size of the particulates of the short-lived radon daughters and two papers about the behaviour of aerosols in containment during a fission products release in the primary circuit and susceptible to be released in atmosphere in the case of containment failure. (N.C.)

  17. Balance of the tropospheric ozone and its relation to stratospheric intrusions indicated by cosmogenic radionuclides. Technical progress report, 1 November 1977--30 June 1978

    International Nuclear Information System (INIS)

    Reiter, R.; Kanter, H.J.; Sladkovic, R.; Jaeger, H.; Mueller, H.

    1978-01-01

    The study of the balance of the tropospheric ozone as a function of atmospheric pollutants and tropospheric transport has been started. Continuous recordings are available of ozone concentration at three levels (3000 m, 1800 m, and 700 m a.s.l.) and of the concentration of the cosmogenic radionuclides 7 Be, 32 P, 33 P, and the CO 2 -concentration. Ozone concentrations >70 ppB have been observed after stratospheric intrusions as well as in consequence of photochemical reactions in the boundary layer. An observation sequence, covering now a period of 20 months, is presented of the stratospheric aerosol layer by means of lidar monitoring. Possible errors in the measuring technique are discussed. A filter photospectrometer for the measurement of the atmospheric total ozone is described, its suitability is checked by a direct intercomparison with a Dobson spectrometer

  18. Stratospheric BrONO2 observed by MIPAS

    Directory of Open Access Journals (Sweden)

    H. Fischer

    2009-03-01

    Full Text Available The first measurements of stratospheric bromine nitrate (BrONO2 are reported. Bromine nitrate has been clearly identified in atmospheric infrared emission spectra recorded with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS aboard the European Envisat satellite, and stratospheric concentration profiles have been determined for different conditions (day and night, different latitudes. The BrONO2 concentrations show strong day/night variations, with much lower concentrations during the day. Maximum volume mixing ratios observed during night are 20 to 25 pptv. The observed concentration profiles are in agreement with estimations from photochemical models and show that the current understanding of stratospheric bromine chemistry is generally correct.

  19. The economics (or lack thereof) of aerosol geoengineering

    Science.gov (United States)

    Goes, M.; Keller, K.; Tuana, N.

    2009-04-01

    Anthropogenic greenhouse gas emissions are changing the Earth's climate and impose substantial risks for current and future generations. What are scientifically sound, economically viable, and ethically defendable strategies to manage these climate risks? Ratified international agreements call for a reduction of greenhouse gas emissions to avoid dangerous anthropogenic interference with the climate system. Recent proposals, however, call for the deployment of a different approach: to geoengineer climate by injecting aerosol precursors into the stratosphere. Published economic studies typically suggest that substituting aerosol geoengineering for abatement of carbon dioxide emissions results in large net monetary benefits. However, these studies neglect the risks of aerosol geoengineering due to (i) the potential for future geoengineering failures and (ii) the negative impacts associated with the aerosol forcing. Here we use a simple integrated assessment model of climate change to analyze potential economic impacts of aerosol geoengineering strategies over a wide range of uncertain parameters such as climate sensitivity, the economic damages due to climate change, and the economic damages due to aerosol geoengineering forcing. The simplicity of the model provides the advantages of parsimony and transparency, but it also imposes severe caveats on the interpretation of the results. For example, the analysis is based on a globally aggregated model and is hence silent on the question of intragenerational distribution of costs and benefits. In addition, the analysis neglects the effects of endogenous learning about the climate system. We show that the risks associated with a future geoengineering failure and negative impacts of aerosol forcings can cause geoenginering strategies to fail an economic cost-benefit test. One key to this finding is that a geoengineering failure would lead to dramatic and abrupt climatic changes. The monetary damages due to this failure can

  20. Aerosols from biomass combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T

    2001-07-01

    This report is the proceedings of a seminar on biomass combustion and aerosol production organised jointly by the International Energy Agency's (IEA) Task 32 on bio energy and the Swiss Federal Office of Energy (SFOE). This collection of 16 papers discusses the production of aerosols and fine particles by the burning of biomass and their effects. Expert knowledge on the environmental impact of aerosols, formation mechanisms, measurement technologies, methods of analysis and measures to be taken to reduce such emissions is presented. The seminar, visited by 50 participants from 11 countries, shows, according to the authors, that the reduction of aerosol emissions resulting from biomass combustion will remain a challenge for the future.

  1. SAGE aerosol measurements. Volume 1, February 21, 1979 to December 31, 1979

    International Nuclear Information System (INIS)

    Mccormick, M.P.

    1985-10-01

    The Stratospheric Aerosol and Gas Experiment (SAGE) satellite system, launched on February 18, 1979, provides profiles of aerosol extinction, ozone concentration, and nitrogen dioxide concentration between about 80 N and 80 S. Zonal averages, separated into sunrise and sunset events, and seasonal averages of the aerosol extinction at 1.00 microns and 0.45 microns ratios of the aerosol extinction to the molecular extinction at 1.00 microns, and ratios of the aerosol extinction at 0.45 microns to the aerosol extinction at 1.00 microns are given. The averages for 1979 are shown in tables and in profile and contour plots (as a function of altitude and latitude). In addition, temperature data provided by the National Oceanic and Atmospheric Administration (NOAA) for the time and location of each SAGE measurement are averaged and shown in a similar format. Typical values of the peak aerosol extinction were 0.0001 to 0.0002 km at 1.00 microns depth values for the 1.00 microns channel varied between 0.001 and 0.002 over all latitudes

  2. Seasonal dependence of aerosol processing in urban Philadelphia

    Science.gov (United States)

    Avery, A. M.; Waring, M. S.; DeCarlo, P. F.

    2017-12-01

    Urban aerosols pose an important threat to human health due to the conflation of emissions and concentrated population exposed. Winter and summer aerosol and trace gas measurements were taken in downtown Philadelphia in 2016. Measurements included aerosol composition and size with an Aerodyne Aerosol Mass Spectrometer (AMS), particle size distributions with an SMPS, and an aethalometer. Trace gas measurements of O3, NO, CH4, CO, and CO2 were taken concurrently. Sampling in seasonal extremes provided contrast in aerosol and trace gas composition, aerosol processing, and emission factors. Inorganic aerosol components contributed approximately 60% of the submicron aerosol mass, while summertime aerosol composition was roughly 70% organic matter. Positive Matrix Factorization (PMF) on the organic aerosol (OA) matrix revealed three factors in common in each season, including an oxygenated organic aerosol (OOA) factor with different temporal behavior in each season. In summertime, OOA varied diurnally with ozone and daytime temperature, but in the wintertime, it was anti-correlated with ozone and temperature, and instead trended with calculated liquid water, indicating a seasonally-dependent processing of organic aerosol in Philadelphia's urban environment. Due to the inorganic dominant winter aerosol, liquid water much higher (2.65 μg/m3) in winter than in summer (1.54 μg/m3). Diurnally varying concentrations of background gas phase species (CH4, CO2) were higher in winter and varied less as a result of boundary layer conditions; ozone was also higher in background in winter than summer. Winter stagnation events with low windspeed showed large buildup of trace gases CH4, CO, CO2, and NO. Traffic related aerosol was also elevated with black carbon and hydrocarbon-like OA (HOA) plumes of each at 3-5 times higher than the winter the average value for each. Winter ratios of HOA to black carbon were significantly higher in the winter than the summer due to lower

  3. Stratonauts pioneers venturing into the stratosphere

    CERN Document Server

    Ehrenfried, Manfred "Dutch"

    2014-01-01

    Stratonauts chronicles humankind’s quest for ever higher altitudes from ancient times to the present. It is based upon history, science and technology, and tells some interesting and fascinating stories along the way. It pays tribute to those killed while attempting to reach the stratosphere over the past several centuries.   “Dutch” von Ehrenfried uses his personal experience as a NASA sensor operator on the RB-57F, flying to an altitude of 70,000 feet, as well as the input and experience from other RB-57F, U-2, A-12, SR-71 and F-104 pilots. Although many of the aircraft and balloons are described, more emphasis is placed on the crews and what they went through. This book is intended for aviators of all kinds and flying enthusiasts in general.

  4. Devices and methods for generating an aerosol

    KAUST Repository

    Bisetti, Fabrizio; Scribano, Gianfranco

    2016-01-01

    Aerosol generators and methods of generating aerosols are provided. The aerosol can be generated at a stagnation interface between a hot, wet stream and a cold, dry stream. The aerosol has the benefit that the properties of the aerosol can

  5. Stratospheric sulfate geoengineering impacts on global agriculture

    Science.gov (United States)

    Xia, L.; Robock, A.; Lawrence, P.; Lombardozzi, D.

    2015-12-01

    Stratospheric sulfate geoengineering has been proposed to reduce the impacts of anthropogenic climate change. If it is ever used, it would change agricultural production, and so is one of the future climate scenarios for the third phase of the Global Gridded Crop Model Intercomparison. As an example of those impacts, we use the Community Land Model (CLM-crop 4.5) to simulate how climate changes from the G4 geoengineering scenario from the Geoengineering Modeling Intercomparison Project. The G4 geoengineering scenario specifies, in combination with RCP4.5 forcing, starting in 2020 daily injections of a constant amount of SO2 at a rate of 5 Tg SO2 per year at one point on the Equator into the lower stratosphere. Eight climate modeling groups have completed G4 simulations. We use the crop model to simulate the impacts of climate change (temperature, precipitation, and solar radiation) on the global agriculture system for five crops - rice, maize, soybeans, cotton, and sugarcane. In general, without irrigation, compared with the reference run (RCP4.5), global production of cotton, rice and sugarcane would increase significantly due to the cooling effect. Maize and soybeans show different regional responses. In tropical regions, maize and soybean have a higher yield in G4 compared with RCP4.5, while in the temperate regions they have a lower yield under a geoengineered climate. Impacts on specific countries in terms of different crop production depend on their locations. For example, the United States and Argentina show soybean production reduction of about 15% under G4 compared to RCP4.5, while Brazil increases soybean production by about 10%.

  6. A Simple Model of Global Aerosol Indirect Effects

    Science.gov (United States)

    Ghan, Steven J.; Smith, Steven J.; Wang, Minghuai; Zhang, Kai; Pringle, Kirsty; Carslaw, Kenneth; Pierce, Jeffrey; Bauer, Susanne; Adams, Peter

    2013-01-01

    Most estimates of the global mean indirect effect of anthropogenic aerosol on the Earth's energy balance are from simulations by global models of the aerosol lifecycle coupled with global models of clouds and the hydrologic cycle. Extremely simple models have been developed for integrated assessment models, but lack the flexibility to distinguish between primary and secondary sources of aerosol. Here a simple but more physically based model expresses the aerosol indirect effect (AIE) using analytic representations of cloud and aerosol distributions and processes. Although the simple model is able to produce estimates of AIEs that are comparable to those from some global aerosol models using the same global mean aerosol properties, the estimates by the simple model are sensitive to preindustrial cloud condensation nuclei concentration, preindustrial accumulation mode radius, width of the accumulation mode, size of primary particles, cloud thickness, primary and secondary anthropogenic emissions, the fraction of the secondary anthropogenic emissions that accumulates on the coarse mode, the fraction of the secondary mass that forms new particles, and the sensitivity of liquid water path to droplet number concentration. Estimates of present-day AIEs as low as 5 W/sq m and as high as 0.3 W/sq m are obtained for plausible sets of parameter values. Estimates are surprisingly linear in emissions. The estimates depend on parameter values in ways that are consistent with results from detailed global aerosol-climate simulation models, which adds to understanding of the dependence on AIE uncertainty on uncertainty in parameter values.

  7. Long-term changes of the upper stratosphere as seen by Japanese rocketsondes at Ryori (39°N, 141°E

    Directory of Open Access Journals (Sweden)

    P. Keckhut

    1999-09-01

    Full Text Available Wind and temperature profiles measured routinely by rockets at Ryori (Japan since 1970 are analysed to quantify interannual changes that occur in the upper stratosphere. The analysis involved using a least square fitting of the data with a multiparametric adaptative model composed of a linear combination of some functions that represent the main expected climate forcing responses of the stratosphere. These functions are seasonal cycles, solar activity changes, stratospheric optical depth induced by volcanic aerosols, equatorial wind oscillations and a possible linear trend. Step functions are also included in the analyses to take into account instrumental changes. Results reveal a small change for wind data series above 45 km when new corrections were introduced to take into account instrumental changes. However, no significant change of the mean is noted for temperature even after sondes were improved. While wind series reveal no significant trends, a significant cooling of 2.0 to 2.5 K/decade is observed in the mid upper stratosphere using this analysis method. This cooling is more than double the cooling predicted by models by a factor of more than two. In winter, it may be noted that the amplitude of the atmospheric response is enhanced. This is probably caused by the larger ozone depletion and/or by some dynamical feedback effects. In winter, cooling tends to be smaller around 40-45 km (in fact a warming trend is observed in December as already observed in other data sets and simulated by models. Although the winter response to volcanic aerosols is in good agreement with numerical simulations, the solar signature is of the opposite sign to that expected. This is not understood, but it has already been observed with other data sets.Key words. Atmospheric composition and structure (evolution of one atmosphere; pressure · density · and temperature · Meteorology and atmospheric dynamics (middle atmosphere dynamics

  8. Long-term changes of the upper stratosphere as seen by Japanese rocketsondes at Ryori (39°N, 141°E

    Directory of Open Access Journals (Sweden)

    P. Keckhut

    Full Text Available Wind and temperature profiles measured routinely by rockets at Ryori (Japan since 1970 are analysed to quantify interannual changes that occur in the upper stratosphere. The analysis involved using a least square fitting of the data with a multiparametric adaptative model composed of a linear combination of some functions that represent the main expected climate forcing responses of the stratosphere. These functions are seasonal cycles, solar activity changes, stratospheric optical depth induced by volcanic aerosols, equatorial wind oscillations and a possible linear trend. Step functions are also included in the analyses to take into account instrumental changes. Results reveal a small change for wind data series above 45 km when new corrections were introduced to take into account instrumental changes. However, no significant change of the mean is noted for temperature even after sondes were improved. While wind series reveal no significant trends, a significant cooling of 2.0 to 2.5 K/decade is observed in the mid upper stratosphere using this analysis method. This cooling is more than double the cooling predicted by models by a factor of more than two. In winter, it may be noted that the amplitude of the atmospheric response is enhanced. This is probably caused by the larger ozone depletion and/or by some dynamical feedback effects. In winter, cooling tends to be smaller around 40-45 km (in fact a warming trend is observed in December as already observed in other data sets and simulated by models. Although the winter response to volcanic aerosols is in good agreement with numerical simulations, the solar signature is of the opposite sign to that expected. This is not understood, but it has already been observed with other data sets.

    Key words. Atmospheric composition and structure (evolution of one atmosphere; pressure · density · and temperature · Meteorology and atmospheric dynamics (middle atmosphere dynamics

  9. Simulation of stratospheric water vapor trends: impact on stratospheric ozone chemistry

    Directory of Open Access Journals (Sweden)

    A. Stenke

    2005-01-01

    Full Text Available A transient model simulation of the 40-year time period 1960 to 1999 with the coupled climate-chemistry model (CCM ECHAM4.L39(DLR/CHEM shows a stratospheric water vapor increase over the last two decades of 0.7 ppmv and, additionally, a short-term increase after major volcanic eruptions. Furthermore, a long-term decrease in global total ozone as well as a short-term ozone decline in the tropics after volcanic eruptions are modeled. In order to understand the resulting effects of the water vapor changes on lower stratospheric ozone chemistry, different perturbation simulations were performed with the CCM ECHAM4.L39(DLR/CHEM feeding the water vapor perturbations only to the chemistry part. Two different long-term perturbations of lower stratospheric water vapor, +1 ppmv and +5 ppmv, and a short-term perturbation of +2 ppmv with an e-folding time of two months were applied. An additional stratospheric water vapor amount of 1 ppmv results in a 5–10% OH increase in the tropical lower stratosphere between 100 and 30 hPa. As a direct consequence of the OH increase the ozone destruction by the HOx cycle becomes 6.4% more effective. Coupling processes between the HOx-family and the NOx/ClOx-family also affect the ozone destruction by other catalytic reaction cycles. The NOx cycle becomes 1.6% less effective, whereas the effectiveness of the ClOx cycle is again slightly enhanced. A long-term water vapor increase does not only affect gas-phase chemistry, but also heterogeneous ozone chemistry in polar regions. The model results indicate an enhanced heterogeneous ozone depletion during antarctic spring due to a longer PSC existence period. In contrast, PSC formation in the northern hemisphere polar vortex and therefore heterogeneous ozone depletion during arctic spring are not affected by the water vapor increase, because of the less PSC activity. Finally, this study shows that 10% of the global total ozone decline in the transient model run

  10. Pollutants identification of ambient aerosols by two types of aerosol mass spectrometers over southeast coastal area, China.

    Science.gov (United States)

    Yan, Jinpei; Chen, Liqi; Lin, Qi; Zhao, Shuhui; Li, Lei

    2018-02-01

    Two different aerosol mass spectrometers, Aerodyne Aerosol Mass Spectrometer (AMS) and Single Particle Aerosol Mass Spectrometer (SPAMS) were deployed to identify the aerosol pollutants over Xiamen, representing the coastal urban area. Five obvious processes were classified during the whole observation period. Organics and sulfate were the dominant components in ambient aerosols over Xiamen. Most of the particles were in the size range of 0.2-1.0μm, accounting for over 97% of the total particles measured by both instruments. Organics, as well as sulfate, measured by AMS were in good correlation with measured by SPAMS. However, high concentration of NH 4 + was obtained by AMS, while extremely low value of NH 4 + was detected by SPAMS. Contrarily, high particle number counts of NO 3 - and Cl - were given by SPAMS while low concentrations of NO 3 - and Cl - were measured by AMS. The variations of POA and SOA obtained from SPAMS during event 1 and event 2 were in accordance with the analysis of HOA and OOA given by AMS, suggesting that both of AMS and SPAMS can well identify the organic clusters of aerosol particles. Overestimate or underestimate of the aerosol sources and acidity would be present in some circumstances when the measurement results were used to analyze the aerosol properties, because of the detection loss of some species for both instruments. Copyright © 2017. Published by Elsevier B.V.

  11. Laboratory investigation of nitrile ices of Titan's stratospheric clouds

    Science.gov (United States)

    Nna Mvondo, D.; Anderson, C. M.; McLain, J. L.; Samuelson, R. E.

    2017-09-01

    Titan's mid to lower stratosphere contains complex cloud systems of numerous organic ice particles comprised of both hydrocarbon and nitrile compounds. Most of these stratospheric ice clouds form as a result of vapor condensation formation processes. However, there are additional ice emission features such as dicyanoacetylene (C4N2) and the 220 cm-1 ice emission feature (the "Haystack") that are difficult to explain since there are no observed vapor emission features associated with these ices. In our laboratory, using a high-vacuum chamber coupled to a FTIR spectrometer, we are engaged in a dedicated investigation of Titan's stratospheric ices to interpret and constrain Cassini Composite InfraRed Spectrometer (CIRS) far-IR data. We will present laboratory transmittance spectra obtained for propionitrile (CH3CH2CN), cyanogen (C2N2) and hydrogen cyanide (HCN) ices, as well as various combinations of their mixtures, to better understand the cloud chemistry occurring in Titan's stratosphere.

  12. Exposing Microorganisms in the Stratosphere for Planetary Protection

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth’s stratosphere is similar to the surface of Mars: rarified air which is dry, cold, and irradiated. E-MIST is a balloon payload that has 4 independently...

  13. The natural stratosphere of 1974. CIAP monograph 1. Final report

    International Nuclear Information System (INIS)

    1975-09-01

    The Climatic Impact Assessment Program (CIAP) of the U.S. Department of Transportation is charged with the 'assessment' of the impact of future aircraft fleets and other vehicles operating in, or transiting through, the stratosphere. CIAP monograph 1 gives a survey, largely from an experimental standpoint, of what is known in 1974 about the unperturbed stratosphere with respect to an application to stratospheric flight. It reviews the overall structure of the stratosphere, its origin in terms of ozone photochemistry, solar irradiance and overall radiative energy balance, other chemically reactive minor species, and atmospheric motions on a variety of scales of time and distance. The limitations of our understanding are emphasized in the presentation. Also, the monograph examines briefly what is known about the effect of massive injections of nitrogen oxides (from atmospheric nuclear explosions) and sulfur oxides (from major volcanic eruptions)

  14. Is there any chlorine monoxide in the stratosphere?

    Science.gov (United States)

    Mumma, M. J.; Rogers, J. D.; Kostiuk, T.; Deming, D.; Hillman, J. J.; Zipoy, D.

    1983-01-01

    A ground-based search for stratospheric 35-ClO was carried out using an infrared heterodyne spectrometer in the solar absorption mode. Lines due to stratospheric HNO3 and tropospheric OCS were detected at about 0.2 percent absorptance levels, but the expected 0.1 percent lines of ClO in this same region were not seen. We find that stratospheric ClO is at least a factor of seven less abundant than is indicated by in situ measurements, and we set an upper limit of 2.3 x 10 to the 13th molecules/sq cm at the 95 percent confidence level for the integrated vertical column density of ClO. Our results imply that the release of chlorofluorocarbons may be significantly less important for the destruction of stratospheric ozone (O3) than is currently thought. Previously announced in STAR as N83-27518

  15. Possible effects of volcanic eruptions on stratospheric minor constituent chemistry

    Science.gov (United States)

    Stolarski, R. S.; Butler, D. M.

    1979-01-01

    Although stratosphere penetrating volcanic eruptions have been infrequent during the last half century, periods have existed in the last several hundred years when such eruptions were significantly more frequent. Several mechanisms exist for these injections to affect stratospheric minor constituent chemistry, both on the long-term average and for short-term perturbations. These mechanisms are reviewed and, because of the sensitivity of current models of stratospheric ozone to chlorine perturbations, quantitative estimates are made of chlorine injection rates. It is found that, if chlorine makes up as much as 0.5 to 1% of the gases released and if the total gases released are about the same magnitude as the fine ash, then a major stratosphere penetrating eruption could deplete the ozone column by several percent. The estimate for the Agung eruption of 1963 is just under 1% an amount not excluded by the ozone record but complicated by the peak in atmospheric nuclear explosions at about the same time.

  16. The Temperature of the Arctic and Antarctic Lower Stratosphere

    Science.gov (United States)

    Newman, Paul A.; Nash, Eric R.; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    The temperature of the polar lower stratosphere during spring is the key factor in changing the magnitude of ozone loss in the polar vortices. In this talk, we will review the results of Newman et al. [2000] that quantitatively demonstrate that the polar lower stratospheric temperature is primarily controlled by planetary-scale waves. In particular, the tropospheric eddy heat flux in middle to late winter (January--February) is highly correlated with the mean polar stratospheric temperature during March. Strong midwinter planetary wave forcing leads to a warmer spring Arctic lower stratosphere in early spring, while weak midwinter forcing leads to cooler spring Arctic temperatures. In addition, this planetary wave driving also has a strong impact on the strength of the polar vortex. These results from the Northern Hemisphere will be contrasted with the Southern Hemisphere.

  17. Arctic Aerosols and Sources

    DEFF Research Database (Denmark)

    Nielsen, Ingeborg Elbæk

    2017-01-01

    Since the Industrial Revolution, the anthropogenic emission of greenhouse gases has been increasing, leading to a rise in the global temperature. Particularly in the Arctic, climate change is having serious impact where the average temperature has increased almost twice as much as the global during......, ammonium, black carbon, and trace metals. This PhD dissertation studies Arctic aerosols and their sources, with special focus on black carbon, attempting to increase the knowledge about aerosols’ effect on the climate in an Arctic content. The first part of the dissertation examines the diversity...... of aerosol emissions from an important anthropogenic aerosol source: residential wood combustion. The second part, characterizes the chemical and physical composition of aerosols while investigating sources of aerosols in the Arctic. The main instrument used in this research has been the state...

  18. Aerosol in the containment

    International Nuclear Information System (INIS)

    Lanza, S.; Mariotti, P.

    1986-01-01

    The US program LACE (LWR Aerosol Containment Experiments), in which Italy participates together with several European countries, Canada and Japan, aims at evaluating by means of a large scale experimental activity at HEDL the retention in the pipings and primary container of the radioactive aerosol released following severe accidents in light water reactors. At the same time these experiences will make available data through which the codes used to analyse the behaviour of the aerosol in the containment and to verify whether by means of the codes of thermohydraulic computation it is possible to evaluate with sufficient accuracy variable influencing the aerosol behaviour, can be validated. This report shows and compares the results obtained by the participants in the LACE program with the aerosol containment codes NAVA 5 and CONTAIN for the pre-test computations of the test LA 1, in which an accident called containment by pass is simulated

  19. Transport of Ice into the Stratosphere and the Humidification of the Stratosphere over the 21st Century

    Science.gov (United States)

    Dessler, A. E.; Ye, H.; Wang, T.; Schoeberl, M. R.; Oman, L. D.; Douglass, A. R.; Butler, A. H.; Rosenlof, K. H.; Davis, S. M.; Portmann, R. W.

    2016-01-01

    Climate models predict that tropical lower-stratospheric humidity will increase as the climate warms. We examine this trend in two state-of-the-art chemistry-climate models. Under high greenhouse gas emissions scenarios, the stratospheric entry value of water vapor increases by approx. 1 part per million by volume (ppmv) over this century in both models. We show with trajectory runs driven by model meteorological fields that the warming tropical tropopause layer (TTL) explains 50-80% of this increase. The remainder is a consequence of trends in evaporation of ice convectively lofted into the TTL and lower stratosphere. Our results further show that, within the models we examined, ice lofting is primarily important on long time scales - on interannual time scales, TTL temperature variations explain most of the variations in lower stratospheric humidity. Assessing the ability of models to realistically represent ice-lofting processes should be a high priority in the modeling community.

  20. Probability Density Functions for the CALIPSO Lidar Version 4 Cloud-Aerosol Discrimination (CAD) Algorithm

    Science.gov (United States)

    Liu, Z.; Kar, J.; Zeng, S.; Tackett, J. L.; Vaughan, M.; Trepte, C. R.; Omar, A. H.; Hu, Y.; Winker, D. M.

    2017-12-01

    In the CALIPSO retrieval algorithm, detection layers in the lidar measurements is followed by their classification as a "cloud" or "aerosol" using 5-dimensional probability density functions (PDFs). The five dimensions are the mean attenuated backscatter at 532 nm, the layer integrated total attenuated color ratio, the mid-layer altitude, integrated volume depolarization ratio and latitude. The new version 4 (V4) level 2 (L2) data products, released in November 2016, are the first major revision to the L2 product suite since May 2010. Significant calibration changes in the V4 level 1 data necessitated substantial revisions to the V4 L2 CAD algorithm. Accordingly, a new set of PDFs was generated to derive the V4 L2 data products. The V4 CAD algorithm is now applied to layers detected in the stratosphere, where volcanic layers and occasional cloud and smoke layers are observed. Previously, these layers were designated as `stratospheric', and not further classified. The V4 CAD algorithm is also applied to all layers detected at single shot (333 m) resolution. In prior data releases, single shot detections were uniformly classified as clouds. The CAD PDFs used in the earlier releases were generated using a full year (2008) of CALIPSO measurements. Because the CAD algorithm was not applied to stratospheric features, the properties of these layers were not incorporated into the PDFs. When building the V4 PDFs, the 2008 data were augmented with additional data from June 2011, and all stratospheric features were included. The Nabro and Puyehue-Cordon volcanos erupted in June 2011, and volcanic aerosol layers were observed in the upper troposphere and lower stratosphere in both the northern and southern hemispheres. The June 2011 data thus provides the stratospheric aerosol properties needed for comprehensive PDF generation. In contrast to earlier versions of the PDFs, which were generated based solely on observed distributions, construction of the V4 PDFs considered the

  1. Ice Nucleation in the Tropical Tropopause Layer: Implications for Cirrus Occurrence, Cirrus Microphysical Properties, and Dehydration of Air Entering the Stratosphere

    Science.gov (United States)

    Jensen, Eric; Kaercher, Bernd; Ueyama, Rei; Pfister, Leonhard

    2017-01-01

    Recent laboratory experiments have advanced our understanding of the physical properties and ice nucleating abilities of aerosol particles atlow temperatures. In particular, aerosols containing organics will transition to a glassy state at low temperatures, and these glassy aerosols are moderately effective as ice nuclei. These results have implications for ice nucleation in the cold Tropical Tropopause Layer (TTL; 13-19 km). We have developed a detailed cloud microphysical model that includes heterogeneous nucleation on a variety of aerosol types and homogeneous freezing of aqueous aerosols. This model has been incorporated into one-dimensional simulations of cirrus and water vapor driven by meteorological analysis temperature and wind fields. The model includes scavenging of ice nuclei by sedimenting ice crystals. The model is evaluated by comparing the simulated cloud properties and water vapor concentrations with aircraft and satellite measurements. In this presentation, I will discuss the relative importance of homogeneous and heterogeneous ice nucleation, the impact of ice nuclei scavenging as air slowly ascends through the TTL, and the implications for the final dehydration of air parcels crossing the tropical cold-point tropopause and entering the tropical stratosphere.

  2. Measurement of concentrations of 7Be, 90Sr, 134,137Cs, 210Pb and 226Ra in the tropospheric and lower stratospheric air in 1997 and 1998

    International Nuclear Information System (INIS)

    Kownacka, L.; Jaworowski, Z.; Zajac, B.

    1999-01-01

    In this report the results of the vertical distribution of atmospheric particulates concentrations of fission products and natural radionuclides 7 Be, 210 Pb, 226 Ra are presented for 1997 and 1998. The measurements have been carried out over north-eastern part of Poland. The samples of aerosols were collected with airplane samplers at 1, 3, 6, 9, 12 and 15 km altitudes, and with a stationary sampler near the ground level. Concentrations of radiocesium in both stratospheric and ground level air were in 1997 and 1998 lower then before the Chernobyl accident. In the troposphere in 1998 concentration increased by a factor of 6 due to a nuclear incident in Spain. (author)

  3. Potential For Stratospheric Ozone Depletion During Carboniferous

    Science.gov (United States)

    Bill, M.; Goldstein, A. H.

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

  4. Effects of Greenhouse Gas Increase and Stratospheric Ozone Depletion on Stratospheric Mean Age of Air in 1960-2010

    Science.gov (United States)

    Li, Feng; Newman, Paul; Pawson, Steven; Perlwitz, Judith

    2018-01-01

    The relative impacts of greenhouse gas (GHG) increase and stratospheric ozone depletion on stratospheric mean age of air in the 1960-2010 period are quantified using the Goddard Earth Observing System Chemistry-�Climate Model. The experiment compares controlled simulations using a coupled atmosphere-�ocean version of the Goddard Earth Observing System Chemistry-�Climate Model, in which either GHGs or ozone depleting substances, or both factors evolve over time. The model results show that GHGs and ozone-depleting substances have about equal contributions to the simulated mean age decrease, but GHG increases account for about two thirds of the enhanced strength of the lower stratospheric residual circulation. It is also found that both the acceleration of the diabatic circulation and the decrease of the mean age difference between downwelling and upwelling regions are mainly caused by GHG forcing. The results show that ozone depletion causes an increase in the mean age of air in the Antarctic summer lower stratosphere through two processes: (1) a seasonal delay in the Antarctic polar vortex breakup that inhibits young midlatitude air from mixing with the older air inside the vortex, and (2) enhanced Antarctic downwelling that brings older air from middle and upper stratosphere into the lower stratosphere.

  5. Molecular beam studies of stratospheric photochemistry

    Science.gov (United States)

    Moore, Teresa Anne

    1998-12-01

    Photochemistry of chlorine oxide containing species plays a major role in stratospheric ozone depletion. This thesis discusses two photodissociation studies of the key molecules ClONO2 and ClOOCl which were previously thought to only produce Cl-atom (ozone depleting) products at wavelengths relevant to the stratosphere. The development of a molecular beam source of ClOOCl and the photodissociation dynamics of the model system Cl2O are also discussed. In the first chapter, the photochemistry of ClONO2 is examined at 308 nm using the technique of photofragment translational spectroscopy. Two primary decomposition pathways, leading to Cl + NO3 and ClO + NO2, were observed, with a lower limit of 0.33 for the relative yield of ClO. The angular distributions for both channels were anisotropic, indicating that the dissociation occurs within a rotational period. Chapter two revisits the photodissociation dynamics of Cl2O at 248 and 308 nm, on which we had previously reported preliminary findings. At 248 nm, three distinct dissociation pathways leading to Cl + ClO products were resolved. At 308 nm, the angular distribution was slightly more isotropic that previously reported, leaving open the possibility that Cl2O excited at 308 nm lives longer than a rotational period. Chapter three describes the development and optimization of a molecular beam source of ClOOCl. We utilized pulsed laser photolysis of ClA2O to generate ClO radicals, and cooled the cell to promote three body recombination to form ClOOCl. The principal components in the beam were Cl2, Cl2O, and ClOOCl. In the fourth chapter, the photodissociation dynamics of ClOOCl are investigated at 248 and 308 nm. We observed multiple dissociation pathways which produced ClO + ClO and 2Cl + O2 products. The relative Cl:ClO product yields are 1.0:0.13 and 1.0:0.20 for ClOOCl photolysis at 248 and 308 nm, respectively. The upper limit for the relative yield of the ClO + ClO channel was 0.19 at 248 nm and 0.31 at 308 nm

  6. Radiative and Thermal Impacts of Smoke Aerosol Longwave Absorption during Fires in the Moscow Region in Summer 2010

    Science.gov (United States)

    Gorchakova, I. A.; Mokhov, I. I.; Anikin, P. P.; Emilenko, A. S.

    2018-03-01

    The aerosol longwave radiative forcing of the atmosphere and heating rate of the near-surface aerosol layer are estimated for the extreme smoke conditions in the Moscow region in summer 2010. Thermal radiation fluxes in the atmosphere are determined using the integral transmission function and semiempirical aerosol model developed on the basis of standard aerosol models and measurements at the Zvenigorod Scientific Station, Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences. The aerosol radiative forcing reached 33 W/m2 at the lower atmospheric boundary and ranged between-1.0 and 1.0 W/m2 at the upper atmospheric boundary. The heating rate of the 10-m atmospheric layer near surface was up to 0.2 K/h during the maximum smoke conditions on August 7-9. The sensitivity of the aerosol longwave radiative forcing to the changes in the aerosol absorption coefficient and aerosol optical thickness are estimated.

  7. DARE : Dedicated Aerosols Retrieval Experiment

    NARCIS (Netherlands)

    Smorenburg, K.; Courrèges-Lacoste, G.B.; Decae, R.; Court, A.J.; Leeuw, G. de; Visser, H.

    2004-01-01

    At present there is an increasing interest in remote sensing of aerosols from space because of the large impact of aerosols on climate, earth observation and health. TNO has performed a study aimed at improving aerosol characterisation using a space based instrument and state-of-the-art aerosol

  8. Remote Sensing of Aerosol in the Terrestrial Atmosphere from Space: New Missions

    Science.gov (United States)

    Milinevsky, G.; Yatskiv, Ya.; Degtyaryov, O.; Syniavskyi, I.; Ivanov, Yu.; Bovchaliuk, A.; Mishchenko, M.; Danylevsky, V.; Sosonkin, M.; Bovchaliuk, V.

    2015-01-01

    The distribution and properties of atmospheric aerosols on a global scale are not well known in terms of determination of their effects on climate. This mostly is due to extreme variability of aerosol concentrations, properties, sources, and types. Aerosol climate impact is comparable to the effect of greenhouse gases, but its influence is more difficult to measure, especially with respect to aerosol microphysical properties and the evaluation of anthropogenic aerosol effect. There are many satellite missions studying aerosol distribution in the terrestrial atmosphere, such as MISR/Terra, OMI/Aura, AVHHR, MODIS/Terra and Aqua, CALIOP/CALIPSO. To improve the quality of data and climate models, and to reduce aerosol climate forcing uncertainties, several new missions are planned. The gap in orbital instruments for studying aerosol microphysics has arisen after the Glory mission failed during launch in 2011. In this review paper, we describe several planned aerosol space missions, including the Ukrainian project Aerosol-UA that obtains data using a multi-channel scanning polarimeter and wide-angle polarimetric camera. The project is designed for remote sensing of the aerosol microphysics and cloud properties on a global scale.

  9. Air pollution or global warming: Attribution of extreme precipitation changes in eastern China—Comments on "Trends of extreme precipitation in Eastern China and their possible causes"

    Science.gov (United States)

    Wang, Yuan

    2015-10-01

    The recent study "Trends of Extreme Precipitation in Eastern China and Their Possible Causes" attributed the observed decrease/increase of light/heavy precipitation in eastern China to global warming rather than the regional aerosol effects. However, there exist compelling evidence from previous long-term observations and numerical modeling studies, suggesting that anthropogenic pollution is closely linked to the recent changes in precipitation intensity because of considerably modulated cloud physical properties by aerosols in eastern China. Clearly, a quantitative assessment of the aerosol and greenhouse effects on the regional scale is required to identify the primary cause for the extreme precipitation changes.

  10. Water content of aged aerosol

    OpenAIRE

    G. J. Engelhart; L. Hildebrandt; E. Kostenidou; N. Mihalopoulos; N. M. Donahue; S. N. Pandis

    2010-01-01

    The composition and physical properties of aged atmospheric aerosol were characterized at a remote sampling site on the northern coast of Crete, Greece during the Finokalia Aerosol Measurement Experiment in May 2008 (FAME-2008). A reduced Dry-Ambient Aerosol Size Spectrometer (DAASS) was deployed to measure the aerosol water content and volumetric growth factor of fine particulate matter. The particles remained wet even at relative humidity (RH) as low as 20%. The aerosol was acidic during mo...

  11. Dynamics of 2013 Sudden Stratospheric Warming event and its impact on cold weather over Eurasia: Role of planetary wave reflection.

    Science.gov (United States)

    Nath, Debashis; Chen, Wen; Zelin, Cai; Pogoreltsev, Alexander Ivanovich; Wei, Ke

    2016-04-07

    In the present study, we investigate the impact of stratospheric planetary wave reflection on tropospheric weather over Central Eurasia during the 2013 Sudden Stratospheric Warming (SSW) event. We analyze EP fluxes and Plumb wave activity fluxes to study the two and three dimensional aspects of wave propagation, respectively. The 2013 SSW event is excited by the combined influence of wavenumber 1 (WN1) and wavenumber 2 (WN2) planetary waves, which makes the event an unusual one and seems to have significant impact on tropospheric weather regime. We observe an extraordinary development of a ridge over the Siberian Tundra and the North Pacific during first development stage (last week of December 2012) and later from the North Atlantic in the second development stage (first week of January 2013), and these waves appear to be responsible for the excitation of the WN2 pattern during the SSW. The wave packets propagated upward and were then reflected back down to central Eurasia due to strong negative wind shear in the upper stratospheric polar jet, caused by the SSW event. Waves that propagated downward led to the formation of a deep trough over Eurasia and brought extreme cold weather over Kazakhstan, the Southern part of Russia and the Northwestern part of China during mid-January 2013.

  12. THE INFLUENCE OF BENZENE AS A TRACE REACTANT IN TITAN AEROSOL ANALOGS

    Energy Technology Data Exchange (ETDEWEB)

    Trainer, Melissa G. [Planetary Environments Laboratory, Code 699, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sebree, Joshua A. [NASA Postdoctoral Program Fellow, Code 699, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Heidi Yoon, Y.; Tolbert, Margaret A., E-mail: melissa.trainer@nasa.gov [Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Box 216 UCB, Boulder, CO 80309 (United States)

    2013-03-20

    Benzene has been detected in Titan's atmosphere by Cassini instruments, with concentrations ranging from sub-ppb in the stratosphere to ppm in the ionosphere. Sustained levels of benzene in the haze formation region could signify that it is an important reactant in the formation of Titan's organic aerosol. To date, there have not been laboratory investigations to assess the influence of benzene on aerosol properties. We report a laboratory study on the chemical composition of organic aerosol formed from C{sub 6}H{sub 6}/CH{sub 4}/N{sub 2} via far ultraviolet irradiation (120-200 nm). The compositional results are compared to those from aerosol generated by a more ''traditional Titan'' mixture of CH{sub 4}/N{sub 2}. Our results show that even a trace amount of C{sub 6}H{sub 6} (10 ppm) has significant impact on the chemical composition and production rates of organic aerosol. There are several pathways by which photolyzed benzene may react to form larger molecules, both with and without the presence of CH{sub 4}, but many of these reaction mechanisms are only beginning to be explored for the conditions at Titan. Continued work investigating the influence of benzene in aerosol growth will advance understanding of this previously unstudied reaction system.

  13. A Statistical Review of CALIOP Version 3 and Version 4 Cloud Aerosol Discrimination

    Science.gov (United States)

    Zeng, S.

    2016-12-01

    The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission has now delivered a 10-year record of high-resolution profiles of backscatter at 532 nm and 1064 nm and linear depolarization at 532 nm. These long-term active sensor measurements at global scale have led to significant advances in our understanding of the vertical distribution of clouds and aerosols in the atmosphere. In the fall of 2016, the CALIPSO science team is scheduled to release a new version of their cloud and aerosol data products. The new cloud and aerosol discrimination products are derived using updated probability density functions that account for numerous improvements to the CALIOP calibration and the use of the GMAO MERRA-2 meteorological data. Moreover, the CAD algorithm is now applied to all layers detected, thus greatly improving the identification of such features as overshooting convective clouds, stratospheric aerosol layers, and high intensity dust storms. Post-processing modules are added to the standard CAD algorithm to ensure proper identification of (for example) the tenuous edges of cirrus clouds and water clouds lying beneath optically dense smoke layers. This work presents statistical comparisons between the CALIOP version 3 and version 4 data sets. Areas of improvement are highlighted, sources of continuing uncertainty are discussed and a list of best practices for data users is provided.

  14. Simulating gas-aerosol-cirrus interactions: Process-oriented microphysical model and applications

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2003-01-01

    Full Text Available This work describes a process-oriented, microphysical-chemical model to simulate the formation and evolution of aerosols and ice crystals under the conditions prevailing in the upper troposphere and lower stratosphere. The model can be run as a box model or along atmospheric trajectories, and considers mixing, gas phase chemistry of aerosol precursors, binary homogeneous aerosol nucleation, homogeneous and heterogeneous ice nucleation, coagulation, condensation and dissolution, gas retention during particle freezing, gas trapping in growing ice crystals, and reverse processes. Chemical equations are solved iteratively using a second order implicit integration method. Gas-particle interactions and coagulation are treated over various size structures, with fully mass conserving and non-iterative numerical solution schemes. Particle types include quinternary aqueous solutions composed of H2SO4, HNO3, HCl, and HBr with and without insoluble components, insoluble aerosol particles, and spherical or columnar ice crystals deriving from each aerosol type separately. Three case studies are discussed in detail to demonstrate the potential of the model to simulate real atmospheric processes and to highlight current research topics concerning aerosol and cirrus formation near the tropopause. Emphasis is placed on how the formation of cirrus clouds and the scavenging of nitric acid in cirrus depends on small-scale temperature fluctuations and the presence of efficient ice nuclei in the tropopause region, corroborating and partly extending the findings of previous studies.

  15. An assessment of a spiral duct centrifuge using standard and high concentration aerosols

    International Nuclear Information System (INIS)

    Smith, A.D.

    1982-12-01

    The Stoeber spiral duct centrifuge has been calibrated by means of polystyrene latex microspheres for the subsequent measurement of aerosol particle size distributions. Intermediate (1 g m -3 ) ad high (100 g m -3 ) sodium chloride aerosol concentrations have been sampled by the centrifuge to determine possible limitations in the equipment. Corrections have to be made for the effect of Coriolis forces, and aerosol concentrations above 1 g m -3 should be diluted before sampling. The spiral duct centrifuge is an extremely versatile instrument for aerosol analysis, and shows a high degree of reliability when operated under well-defined conditions. (author)

  16. Evolution of stratospheric ozone and water vapour time series studied with satellite measurements

    Directory of Open Access Journals (Sweden)

    A. Jones

    2009-08-01

    Full Text Available The long term evolution of stratospheric ozone and water vapour has been investigated by extending satellite time series to April 2008. For ozone, we examine monthly average ozone values from various satellite data sets for nine latitude and altitude bins covering 60° S to 60° N and 20–45 km and covering the time period of 1979–2008. Data are from the Stratospheric Aerosol and Gas Experiment (SAGE I+II, the HALogen Occultation Experiment (HALOE, the Solar BackscatterUltraViolet-2 (SBUV/2 instrument, the Sub-Millimetre Radiometer (SMR, the Optical Spectrograph InfraRed Imager System (OSIRIS, and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartograpY (SCIAMACHY. Monthly ozone anomalies are calculated by utilising a linear regression model, which also models the solar, quasi-biennial oscillation (QBO, and seasonal cycle contributions. Individual instrument ozone anomalies are combined producing an all instrument average. Assuming a turning point of 1997 and that the all instrument average is represented by good instrumental long term stability, the largest statistically significant ozone declines (at two sigma from 1979–1997 are seen at the mid-latitudes between 35 and 45 km, namely −7.2%±0.9%/decade in the Northern Hemisphere and −7.1%±0.9%/in the Southern Hemisphere. Furthermore, for the period 1997 to 2008 we find that the same locations show the largest ozone recovery (+1.4% and +0.8%/decade respectively compared to other global regions, although the estimated trend model errors indicate that the trend estimates are not significantly different from a zero trend at the 2 sigma level. An all instrument average is also constructed from water vapour anomalies during 1991–2008, using the SAGE II, HALOE, SMR, and the Microwave Limb Sounder (Aura/MLS measurements. We report that the decrease in water vapour values after 2001 slows down around 2004–2005 in the lower tropical stratosphere (20–25 km and has even

  17. Mid-infrared mapping of Jupiter's temperatures, aerosol opacity and chemical distributions with IRTF/TEXES

    Science.gov (United States)

    Fletcher, Leigh N.; Greathouse, T. K.; Orton, G. S.; Sinclair, J. A.; Giles, R. S.; Irwin, P. G. J.; Encrenaz, T.

    2016-11-01

    Global maps of Jupiter's atmospheric temperatures, gaseous composition and aerosol opacity are derived from a programme of 5-20 μm mid-infrared spectroscopic observations using the Texas Echelon Cross Echelle Spectrograph (TEXES) on NASA's Infrared Telescope Facility (IRTF). Image cubes from December 2014 in eight spectral channels, with spectral resolutions of R ∼2000 - 12 , 000 and spatial resolutions of 2-4° latitude, are inverted to generate 3D maps of tropospheric and stratospheric temperatures, 2D maps of upper tropospheric aerosols, phosphine and ammonia, and 2D maps of stratospheric ethane and acetylene. The results are compared to a re-analysis of Cassini Composite Infrared Spectrometer (CIRS) observations acquired during Cassini's closest approach to Jupiter in December 2000, demonstrating that this new archive of ground-based mapping spectroscopy can match and surpass the quality of previous investigations, and will permit future studies of Jupiter's evolving atmosphere. The visibility of cool zones and warm belts varies from channel to channel, suggesting complex vertical variations from the radiatively-controlled upper troposphere to the convective mid-troposphere. We identify mid-infrared signatures of Jupiter's 5-μm hotspots via simultaneous M, N and Q-band observations, which are interpreted as temperature and ammonia variations in the northern Equatorial Zone and on the edge of the North Equatorial Belt (NEB). Equatorial plumes enriched in NH3 gas are located south-east of NH3-desiccated 'hotspots' on the edge of the NEB. Comparison of the hotspot locations in several channels across the 5-20 μm range indicate that these anomalous regions tilt westward with altitude. Aerosols and PH3 are both enriched at the equator but are not co-located with the NH3 plumes. The equatorial temperature minimum and PH3/aerosol maxima have varied in amplitude over time, possibly as a result of periodic equatorial brightenings and the fresh updrafts of

  18. Could aerosol emissions be used for regional heat wave mitigation?

    Directory of Open Access Journals (Sweden)

    D. N. Bernstein

    2013-07-01

    Full Text Available Geoengineering applications by injection of sulfate aerosols into the stratosphere are under consideration as a measure of last resort to counter global warming. Here a potential regional-scale application to offset the impacts of heat waves is critically examined. Using the Weather Research and Forecasting model with fully coupled chemistry (WRF-Chem, the effect of regional-scale sulfate aerosol emission over California in each of two days of the July 2006 heat wave is used to quantify potential reductions in surface temperature as a function of emission rates in a layer at 12 km altitude. Local meteorological factors yield geographical differences in surface air temperature sensitivity. For emission rates of approximately 30 μg m−2 s−1 of sulfate aerosols (with standard WRF-Chem size distribution over the region, temperature decreases of around 7 °C result during the middle part of the day over the Central Valley, one of the areas hardest hit by the heat wave. Regions more ventilated with oceanic air such as Los Angeles have slightly smaller reductions. The length of the hottest part of the day is also reduced. Advection effects on the aerosol cloud must be more carefully forecast for smaller injection regions. Verification of the impacts could be done via measurements of differences in reflected and surface downward shortwave. Such regional geoengineering applications with specific near-term target effects but smaller cost and side effects could potentially provide a means of testing larger scale applications. However, design considerations for regional applications, such as a preference for injection at a level of relatively low wind speed, differ from those for global applications. The size of the required injections and the necessity of injection close to the target region raise substantial concerns. The evaluation of this regional-scale application is thus consistent with global model evaluations, emphasizing that mitigation via

  19. The chemistry of bromine in the stratosphere: Influence of a new rate constant for the reaction BrO + HO2

    Science.gov (United States)

    Pirre, Michel; Marceau, Francois J.; Lebras, Georges; Maguin, Francoise; Poulet, Gille; Ramaroson, Radiela

    1994-01-01

    The impact of new laboratory data for the reaction BrO + HO2 yields HOBr + O2 in the depletion of global stratospheric ozone has been estimated using a one-dimensional photochemical model taking into account the heterogeneous reaction on sulphate aerosols which converts N2O5 into HNO3. Assuring an aerosol loading 2 times as large as the 'background' and a reaction probability of 0.1 for the above heterogeneous reaction, the 6 fold increase in the measured rate constant for the reaction of BrO with HO2 increases the computed depletion of global ozone produced by 20 ppt of total bromine from 2.01 percent to 2.36 percent. The use of the higher rate constant increases the HOBr mixing ratio and makes the bromine partitioning and the ozone depletion very sensitive to the branching ratio of the potential channel forming HBr in the BrO + HO2 reaction.

  20. An Overview of the GEOS-5 Aerosol Reanalysis

    Science.gov (United States)

    da Silva, Arlindo; Colarco, Peter Richard; Damenov, Anton Spasov; Buchard-Marchant, Virginie; Randles, Cynthia A.; Gupta, Pawan

    2011-01-01

    GEOS-5 is the latest version of the NASA Global Modeling and Assimilation Office (GMAO) earth system model. GEOS-5 contains components for atmospheric circulation and composition (including data assimilation), ocean circulation and biogeochemistry, and land surface processes. In addition to traditional meteorological parameters, GEOS-5 includes modules representing the atmospheric composition, most notably aerosols and tropospheric/stratospheric chemical constituents, taking explicit account of the impact of these constituents on the radiative processes of the atmosphere. MERRA is a NASA meteorological reanalysis for the satellite era (1979-present) using GEOS-5. This project focuses on historical analyses of the hydrological cycle on a broad range of weather and climate time scales. As a first step towards an integrated Earth System Analysis (IESA), the GMAO is extending MERRA with reanalyses for other components of the earth system: land, ocean, bio-geochemistry and atmospheric constituents. In this talk we will present results from the MERRA-driven aerosol reanalysis covering the Aqua period (2003-present). The assimilation of Aerosol Optical Depth (AOD) in GEOS-5 involves very careful cloud screening and homogenization of the observing system by means of a Neural Net scheme that translates MODIS radiances into AERONET calibrated AOD. These measurements are further quality controlled using an adaptive buddy check scheme, and assimilated using the Local Displacement Ensemble (LDE) methodology. For this reanalysis, GEOS-5 runs at a nominal 50km horizontal resolution with 72 vertical layers (top at approx. 8Skm). GEOS-5 is driven by daily biomass burning emissions derived from MODIS fire radiative power retrievals. We will present a summary of our efforts to validate such dataset. The GEOS-5 assimilated aerosol fields are first validated by comparison to independent in-situ measurements (AERONET and PM2.5 surface concentrations). In order to asses aerosol

  1. Study of the behaviour of artificial radioactive aerosols. Applications to some problems of atmospheric circulation (1963); Etude du comportement dcs aerosols radioactifs artificiels. Applications a quelques problemes de circulation atmospherique (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-11-15

    The aim of this work, consists in the examination of the behaviour of radioactive aerosols produced in the atmosphere by nuclear explosions, in order to deduce the most general laws governing atmospheric circulation and diffusion. After having given a general table of the radioactive aerosols present the authors consider the validity and the precision of the measurement methods and the concentration of the aerosols at ground level and in the upper atmosphere, as well as their deposition on the ground. The existence is thus demonstrated of a tropospheric equatorial barrier and of discontinuous and seasonal aspects of stratosphere-troposphere transfers. The role is shown of precipitations and dry auto-filtration in the lower atmosphere cleaning processes. This work makes it possible to describe the general behaviour of dust from the stratosphere, and to improve the total radioactive contamination of the globe. (author) [French] L'objectif de ce travail consiste a examiner le comportement des aerosols radioactifs introduits dans l'atmosphere par les explosions nucleaires, pour en deduire les lois les plus generals de la circulation et diffusion atmospheriques. Apres avoir dresse un tableau d'ensemble des aerosols radioactifs presents, on examine la validite et la precision des methodes de mesure de leur concentration, au niveau du sol et en haute atmosphere, ainsi que de leur depot a la surface du sol. On met ainsi en evidence l'existence d'une barriere equatoriale tropospherique; l'aspect discontinu et saisonnier des transferts stratosphere-troposphere; le role des precipitations et de l'auto-filtration seche, dans les processus de nettoyage de la basse atmosphere. Ces etudes permettent de decrire le comportement general des poussieres d'origine stratospherique et d'ameliorer le bilan de la contamination radioactive du globe. (auteur)

  2. Study of the behaviour of artificial radioactive aerosols. Applications to some problems of atmospheric circulation (1963); Etude du comportement dcs aerosols radioactifs artificiels. Applications a quelques problemes de circulation atmospherique (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-11-15

    The aim of this work, consists in the examination of the behaviour of radioactive aerosols produced in the atmosphere by nuclear explosions, in order to deduce the most general laws governing atmospheric circulation and diffusion. After having given a general table of the radioactive aerosols present the authors consider the validity and the precision of the measurement methods and the concentration of the aerosols at ground level and in the upper atmosphere, as well as their deposition on the ground. The existence is thus demonstrated of a tropospheric equatorial barrier and of discontinuous and seasonal aspects of stratosphere-troposphere transfers. The role is shown of precipitations and dry auto-filtration in the lower atmosphere cleaning processes. This work makes it possible to describe the general behaviour of dust from the stratosphere, and to improve the total radioactive contamination of the globe. (author) [French] L'objectif de ce travail consiste a examiner le comportement des aerosols radioactifs introduits dans l'atmosphere par les explosions nucleaires, pour en deduire les lois les plus generals de la circulation et diffusion atmospheriques. Apres avoir dresse un tableau d'ensemble des aerosols radioactifs presents, on examine la validite et la precision des methodes de mesure de leur concentration, au niveau du sol et en haute atmosphere, ainsi que de leur depot a la surface du sol. On met ainsi en evidence l'existence d'une barriere equatoriale tropospherique; l'aspect discontinu et saisonnier des transferts stratosphere-troposphere; le role des precipitations et de l'auto-filtration seche, dans les processus de nettoyage de la basse atmosphere. Ces etudes permettent de decrire le comportement general des poussieres d'origine stratospherique et d'ameliorer le bilan de la contamination radioactive du globe. (auteur)

  3. A New Background Stratospheric Aerosol Model for Use in Atmospheric Radiation Models

    Science.gov (United States)

    1988-07-30

    I. Soufriere 1979 event, J. Atmos. Terr. Phy, 43:1127- 1131. 19. Hirono, M., Fujiwara, M.,and Shibata, T. (1982) Lidar observation of sudden... Soufriere 1979 event, J. Atmos. Terr. Phy, 43:1127- 1131. 19. Hirono, M., Fujiwara, M.,and Shibata, T. (1982) Lidar observation of sudden increases

  4. Towards constraining the stratosphere-troposphere exchange of radiocarbon: strategies of stratospheric 14CO2 measurements using AirCore

    Science.gov (United States)

    Chen, Huilin; Paul, Dipayan; Meijer, Harro; Miller, John; Kivi, Rigel; Krol, Maarten

    2016-04-01

    Radiocarbon (14C) plays an important role in the carbon cycle studies to understand both natural and anthropogenic carbon fluxes, but also in atmospheric chemistry to constrain hydroxyl radical (OH) concentrations in the atmosphere. Apart from the enormous 14C emissions from nuclear bomb testing in the 1950s and 1960s, radiocarbon is primarily produced in the stratosphere due to the cosmogenic production. To this end, better understanding the stratospheric radiocarbon source is very useful to advance the use of radiocarbon for these applications. However, stratospheric 14C observations have been very limited so that there are large uncertainties on the magnitude and the location of the 14C production as well as the transport of radiocarbon from the stratosphere to the troposphere. Recently we have successfully made stratospheric 14C measurements using AirCore samples from Sodankylä, Northern Finland. AirCore is an innovative atmospheric sampling system, which passively collects atmospheric air samples into a long piece of coiled stainless steel tubing during the descent of a balloon flight. Due to the relatively low cost of the consumables, there is a potential to make such AirCore profiling in other parts of the world on a regular basis. In this study, we simulate the 14C in the atmosphere and assess the stratosphere-troposphere exchange of radiocarbon using the TM5 model. The Sodankylä radiocarbon measurements will be used to verify the performance of the model at high latitude. Besides this, we will also evaluate the influence of different cosmogenic 14C production scenarios and the uncertainties in the OH field on the seasonal cycles of radiocarbon and on the stratosphere-troposphere exchange, and based on the results design a strategy to set up a 14C measurement program using AirCore.

  5. Sodium oxide aerosol filtration

    Energy Technology Data Exchange (ETDEWEB)

    Duverger de Cuy, G [DSN/SESTR, Centre de Cadarache, Saint-Paul-lez-Durance (France)

    1979-03-01

    In the scope of the sodium aerosol trapping research effort by the CEA/DSN, the retention capacity and yield were measured for very high efficiency fiberglass filters and several types of prefilters (cyclone agglomerator, fabric prefilters, water scrubbers). (author)

  6. Sodium aerosol recovering device

    International Nuclear Information System (INIS)

    Fujimori, Koji; Ueda, Mitsuo; Tanaka, Kazuhisa.

    1997-01-01

    A main body of a recovering device is disposed in a sodium cooled reactor or a sodium cooled test device. Air containing sodium aerosol is sucked into the main body of the recovering device by a recycling fan and introduced to a multi-staged metal mesh filter portion. The air about against each of the metal mesh filters, and the sodium aerosol in the air is collected. The air having a reduced sodium aerosol concentration circulates passing through a recycling fan and pipelines to form a circulation air streams. Sodium aerosol deposited on each of the metal mesh filters is scraped off periodically by a scraper driving device to prevent clogging of each of the metal filters. (I.N.)

  7. Aerosol chemical physics

    International Nuclear Information System (INIS)

    Marlow, W.H.

    1982-01-01

    A classification of the research fields in the chemical physics of aerosol microparticles is given. The emphasis lies on the microphysics of isolated particles and clusters and on physical transformations and thermodynamics. (LDN)

  8. Sodium oxide aerosol filtration

    International Nuclear Information System (INIS)

    Duverger de Cuy, G.

    1979-01-01

    In the scope of the sodium aerosol trapping research effort by the CEA/DSN, the retention capacity and yield were measured for very high efficiency fiberglass filters and several types of prefilters (cyclone agglomerator, fabric prefilters, water scrubbers). (author)

  9. Aerosols and Climate

    Indian Academy of Sciences (India)

    aerosols, clouds, radiation and climate. ... the solar radiation to pass through but absorb most of infrared radiation emitted .... Fine soil and sand particles become airborne due to wind. Over ..... its sampling is difficult compared to other species.

  10. Aerosols from biomass combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T.

    2001-07-01

    This report is the proceedings of a seminar on biomass combustion and aerosol production organised jointly by the International Energy Agency's (IEA) Task 32 on bio energy and the Swiss Federal Office of Energy (SFOE). This collection of 16 papers discusses the production of aerosols and fine particles by the burning of biomass and their effects. Expert knowledge on the environmental impact of aerosols, formation mechanisms, measurement technologies, methods of analysis and measures to be taken to reduce such emissions is presented. The seminar, visited by 50 participants from 11 countries, shows, according to the authors, that the reduction of aerosol emissions resulting from biomass combustion will remain a challenge for the future.

  11. Impact of lower stratospheric ozone on seasonal prediction systems

    Directory of Open Access Journals (Sweden)

    Kelebogile Mathole

    2014-03-01

    Full Text Available We conducted a comparison of trends in lower stratospheric temperatures and summer zonal wind fields based on 27 years of reanalysis data and output from hindcast simulations using a coupled ocean-atmospheric general circulation model (OAGCM. Lower stratospheric ozone in the OAGCM was relaxed to the observed climatology and increasing greenhouse gas concentrations were neglected. In the reanalysis, lower stratospheric ozone fields were better represented than in the OAGCM. The spring lower stratospheric/ upper tropospheric cooling in the polar cap observed in the reanalysis, which is caused by a direct ozone depletion in the past two decades and is in agreement with previous studies, did not appear in the OAGCM. The corresponding summer tropospheric response also differed between data sets. In the reanalysis, a statistically significant poleward trend of the summer jet position was found, whereas no such trend was found in the OAGCM. Furthermore, the jet position in the reanalysis exhibited larger interannual variability than that in the OAGCM. We conclude that these differences are caused by the absence of long-term lower stratospheric ozone changes in the OAGCM. Improper representation or non-inclusion of such ozone variability in a prediction model could adversely affect the accuracy of the predictability of summer rainfall forecasts over South Africa.

  12. Stratospheric ozone: History and concepts and interactions with climate

    Directory of Open Access Journals (Sweden)

    Bekki S.

    2009-02-01

    Full Text Available Although in relatively low concentration of a few molecules per million of e e air molecules, atmospheric ozone (trioxygen O3 is essential to sustaining life on the surface of the Earth. Indeed, by absorbing solar radiation between 240 and 320 nm, it shields living organisms including humans from the very harmful ultraviolet radiation UV-B. About 90% of the ozone resides in the stratosphere, a region that extends from the tropopause, whose altitude ranges from 7 km at the poles to 17 km in the tropics, to the stratopause located at about 50 km altitude. Stratospheric ozone is communally referred as the « ozone layer ». Unlike the atmosphere surrounding it, the stratosphere is vertically stratified and stable because the temperature increases with height within it. This particularity originates from heating produced by the absorption of UV radiation by stratospheric ozone. The present chapter describes the main mechanisms that govern the natural balance of ozone in the stratosphere, and its disruption under the influence of human activities.

  13. Emergency Protection from Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Cristy, G.A.

    2001-11-13

    Expedient methods were developed that could be used by an average person, using only materials readily available, to protect himself and his family from injury by toxic (e.g., radioactive) aerosols. The most effective means of protection was the use of a household vacuum cleaner to maintain a small positive pressure on a closed house during passage of the aerosol cloud. Protection factors of 800 and above were achieved.

  14. Emergency protection from aerosols

    International Nuclear Information System (INIS)

    Cristy, G.A.; Chester, C.V.

    1981-07-01

    Expedient methods were developed that could be used by an average person, using only materials readily available, to protect himself and his family from injury by toxic (e.g., radioactive) aerosols. The most effective means of protection was the use of a household vacuum cleaner to maintain a small positive pressure on a closed house during passage of the aerosol cloud. Protection factors of 800 and above were achieved

  15. MISR Aerosol Typing

    Science.gov (United States)

    Kahn, Ralph A.

    2014-01-01

    AeroCom is an open international initiative of scientists interested in the advancement of the understanding of global aerosol properties and aerosol impacts on climate. A central goal is to more strongly tie and constrain modeling efforts to observational data. A major element for exchanges between data and modeling groups are annual meetings. The meeting was held September 20 through October 2, 1014 and the organizers would like to post the presentations.

  16. A method for sampling microbial aerosols using high altitude balloons.

    Science.gov (United States)

    Bryan, N C; Stewart, M; Granger, D; Guzik, T G; Christner, B C

    2014-12-01

    Owing to the challenges posed to microbial aerosol sampling at high altitudes, very little is known about the abundance, diversity, and extent of microbial taxa in the Earth-atmosphere system. To directly address this knowledge gap, we designed, constructed, and tested a system that passively samples aerosols during ascent through the atmosphere while tethered to a helium-filled latex sounding balloon. The sampling payload is ~ 2.7 kg and comprised of an electronics box and three sampling chambers (one serving as a procedural control). Each chamber is sealed with retractable doors that can be commanded to open and close at designated altitudes. The payload is deployed together with radio beacons that transmit GPS coordinates (latitude, longitude and altitude) in real time for tracking and recovery. A cut mechanism separates the payload string from the balloon at any desired altitude, returning all equipment safely to the ground on a parachute. When the chambers are opened, aerosol sampling is performed using the Rotorod® collection method (40 rods per chamber), with each rod passing through 0.035 m3 per km of altitude sampled. Based on quality control measurements, the collection of ~ 100 cells rod(-1) provided a 3-sigma confidence level of detection. The payload system described can be mated with any type of balloon platform and provides a tool for characterizing the vertical distribution of microorganisms in the troposphere and stratosphere. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Stratospheric Water and OzOne Satellite Homogenized (SWOOSH) data set

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) data set is a merged record of stratospheric ozone and water vapor measurements taken by a number of...

  18. The Distribution of Hydrogen, Nitrogen, and Chlorine Radicals in the Lower Stratosphere: Implications for Changes in O3 due to Emission of NO(y) from Supersonic Aircraft

    Science.gov (United States)

    Salawitch, R. J.; Wofsy, S. C.; Wennberg, P. O.; Cohen, R. C.; Anderson, J. G.; Fahey, D. W.; Gao, R. S.; Keim, E. R.; Woodbridge, E. L.; Stimpfle, R. M.; hide

    1994-01-01

    In situ measurements of hydrogen, nitrogen, and chlorine radicals obtained in the lower stratosphere during the Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE) are compared to results from a photochemical model that assimilates measurements of radical precursors and environmental conditions. Models allowing for heterogeneous hydrolysis of N2O5 agree well with measured concentrations of NO and ClO, but concentrations of HO2 and OH are underestimated by 10 to 25%, concentrations of NO2 are overestimated by 10 to 30%, and concentrations of HCl are overestimated by a factor of 2. Discrepancies for [OH] and [HO2] are reduced if we allow for higher yields of O(sup 1)D) from 03 photolysis and for heterogeneous production of HNO2. The data suggest more efficient catalytic removal of O3 by hydrogen and halogen radicals relative to nitrogen oxide radicals than predicted by models using recommended rates and cross sections. Increases in [O3] in the lower stratosphere may be larger in response to inputs of NO(sub y) from supersonic aircraft than estimated by current assessment models.

  19. Poster 7: Could PAH or HAC explain the Titan's stratosphere absorption around 3.4 µm revealed by solar occultations?

    Science.gov (United States)

    Cordier, Daniel; Cours, Thibaud; Rey, Michael; Maltagliati, Luca; Seignovert, Benoit; Biennier, Ludovic

    2016-06-01

    In 2006, during Cassini's 10th flyby of Titan (T10), Bellucci et al. (2009) observed a solar occultation by Titan's atmosphere through the solar port of the Cassini/VIMS instrument. These authors noticed the existence of an unexplained additional absorption superimposed to the CH4 3.3 µm band. Because they were unable to model this absorption with gases, they attributed this intriguing feature to the signature of solid state organic components. Kim et al. (2011) revisited the data collected by Bellucci et al. (2009) and they considered the possible contribution of aerosols formed by hydrocarbon ices. They specifically took into account C2H6, CH4, CH3CN, C5H12 and C6H12 ices. More recently, Maltagliati et al. (2015) analyzed a set of four VIMS solar occultations, corresponding to flybys performed between January 2006 and September 2011 at different latitudes. They confirmed the presence of the 3.3 µm absorption in all occultations and underlined the possible importance of gaseous ethane, which has a strong plateau of absorption lines in that wavelength range.In this work, we show that neither hydrocarbon ices nor molecular C2H6 cannot satisfactorily explain the observed absorption. Our simulations speak in favor of an absorption due to the presence of PAH molecules or HAC in the stratosphere of Titan. PAH have been already considered by Lopes-Puertas et al. (2013) at altitudes larger than ˜900 km and tentatively identified in the stratosphere by Maltagliati et al. (2015); PAH and HAC are good candidates for Titan's aerosols precursors.

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

    OpenAIRE

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

    2015-01-01

    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 chem- istry modules, but use prescribed ozone instead. This can lead to insufficient representation between stratosphere and troposphere. The SWIFT stratospheric ozone chem...

  1. Effects of stratospheric perturbations on the solar radiation budget

    International Nuclear Information System (INIS)

    Luther, F.M.

    1978-04-01

    The changes in solar absorption and in local heating rates due to perturbations to O 3 and NO 2 concentrations caused by stratospheric injection of NO/sub x/ and CFM pollutants are assessed. The changes in species concentration profiles are derived from theoretical calculations using a transport-kinetics model. Because of significant changes in our understanding of stratospheric chemistry during the past year, the assessment of the effect of stratospheric perturbations on the solar radiation budget differs from previous assessments. Previously, a reduction in O 3 due to an NO/sub x/ injection caused a net decrease in the gaseous solar absorption;now the same perturbation leads to a net increase. The implication of these changes on the surface temperature is also discussed

  2. Aerosol effects on UV radiation

    International Nuclear Information System (INIS)

    Koepke, P.; Reuder, J.; Schwander, H.

    2000-01-01

    The reduction of erythemally weighted UV-irradiance (given as UV index, UVI) due to aerosols is analyzed by variation of the tropospheric particles in a wide, but realistic range. Varied are amount and composition of the particles and relative humidity and thickness of the mixing layer. The reduction of UVI increases with aerosol optical depth and the UV change is around 10% for a change aerosol optical depth from 0.25 to 0.1 and 0.4 respectively. Since both aerosol absorption and scattering are of relevance, the aerosol effect depends besides total aerosol amount on relative amount of soot and on relative humidity

  3. Propagation of respiratory aerosols by the vuvuzela.

    Directory of Open Access Journals (Sweden)

    Ka-Man Lai

    Full Text Available Vuvuzelas, the plastic blowing horns used by sports fans, recently achieved international recognition during the FIFA World Cup soccer tournament in South Africa. We hypothesised that vuvuzelas might facilitate the generation and dissemination of respiratory aerosols. To investigate the quantity and size of aerosols emitted when the instrument is played, eight healthy volunteers were asked to blow a vuvuzela. For each individual the concentration of particles in expelled air was measured using a six channel laser particle counter and the duration of blowing and velocity of air leaving the vuvuzela were recorded. To allow comparison with other activities undertaken at sports events each individual was also asked to shout and the measurements were repeated while using a paper cone to confine the exhaled air. Triplicate measurements were taken for each individual. The mean peak particle counts were 658 × 10(3 per litre for the vuvuzela and 3.7 × 10(3 per litre for shouting, representing a mean log(10 difference of 2.20 (95% CI: 2.03,2.36; p 97% of particles captured from either the vuvuzela or shouting were between 0.5 and 5 microns in diameter. Mean peak airflows recorded for the vuvuzela and shouting were 6.1 and 1.8 litres per second respectively. We conclude that plastic blowing horns (vuvuzelas have the capacity to propel extremely large numbers of aerosols into the atmosphere of a size able to penetrate the lower lung. Some respiratory pathogens are spread via contaminated aerosols emitted by infected persons. Further investigation is required to assess the potential of the vuvuzela to contribute to the transmission of aerosol borne diseases. We recommend, as a precautionary measure, that people with respiratory infections should be advised not to blow their vuvuzela in enclosed spaces and where there is a risk of infecting others.

  4. Variability of Irreversible Poleward Transport in the Lower Stratosphere

    Science.gov (United States)

    Olsen, Mark; Douglass, Anne; Newman, Paul; Nash, Eric; Witte, Jacquelyn; Ziemke, Jerry

    2011-01-01

    The ascent and descent of the Brewer-Dobson circulation plays a large role in determining the distributions of many constituents in the extratropical lower stratosphere. However, relatively fast, quasi-horizontal transport out of the tropics and polar regions also significantly contribute to determining these distributions. The tropical tape recorder signal assures that there must be outflow from the tropics into the extratropical lower stratosphere. The phase of the quasi-biennial oscillation (QBO) and state of the polar vortex are known to modulate the transport from the tropical and polar regions, respectively. In this study we examine multiple years of ozone distributions in the extratropical lower stratosphere observed by the Aura Microwave Limb Sounder (MLS) and the Aura High Resolution Dynamic Limb Sounder (HIRDLS). The distributions are compared with analyses of irreversible, meridional isentropic transport. We show that there is considerable year-to-year seasonal variability in the amount of irreversible transport from the tropics, which is related to both the phase of the QBO and the state of the polar vortex. The reversibility of the transport is consistent with the number of observed breaking waves. The variability of the atmospheric index of refraction in the lower stratosphere is shown to be significantly correlated with the wave breaking and amount of irreversible transport. Finally, we will show that the seasonal extratropical stratosphere to troposphere transport of ozone can be substantially modulated by the amount of irreversible meridional transport in the lower stratosphere and we investigate how observable these differences are in data of tropospheric ozone.

  5. Characterization of intense aerosol episodes in the Mediterranean basin from satellite observations

    Science.gov (United States)

    Gkikas, Antonis; Hatzianastassiou, Nikos; Mihalopoulos, Nikolaos

    2014-05-01

    The properties and distribution of aerosols over the broader Mediterranean region are complex since particles of different nature are either produced within its boundaries or transported from other regions. Thus, coarse dust aerosols are transported primarily from Sahara and secondarily from Middle East, while fine polluted aerosols are either produced locally from anthropogenic activities or they are transported from neighbouring or remote European areas. Also during summer biomass aerosols are transported towards the Mediterranean, originating from massive and extended fires occurring in northern Balkans and Eastern Europe and favoured by the prevailing synoptic conditions. In addition, sea-salt aerosols originate from the Mediterranean Sea or the Atlantic Ocean. Occasionally, aerosols are encountered at very high concentrations (aerosol episodes or events) significantly affecting atmospheric dynamics and climate as well as human health. Given the coexistence of different aerosols as internal and external mixtures characterizing and discriminating between the different types of aerosol episodes is a big challenge. A characterization and classification of intense aerosol episodes in the Mediterranean basin (March 2000 - February 2007) is attempted in the present study. This is achieved by implementing an objective and dynamic algorithm which uses daily aerosol optical properties derived from satellite measurements, namely MODIS-Terra, Earth Probe (EP)-TOMS and OMI-Aura. The aerosol episodes are first classified into strong and extreme ones, according to their intensity, by means of aerosol optical depth at 550nm (AOD550nm). Subsequently, they are discriminated into the following aerosol types: (i) biomass/urban-industrial (BU), (ii) desert dust (DD), (iii) sea-salt like (SS), (iv) mixed (MX) and (v) undetermined (UN). The classification is based on aerosol optical properties accounting for the particles' size (Ångström exponent, Effective radius), the

  6. Impact and mitigation of stratospheric ozone depletion by chemical rockets

    International Nuclear Information System (INIS)

    Mcdonald, A.J.

    1992-03-01

    The American Institute of Aeronautics and Astronautics (AIAA) conducted a workshop in conjunction with the 1991 AIAA Joint Propulsion Conference in Sacramento, California, to assess the impact of chemical rocket propulsion on the environment. The workshop included recognized experts from the fields of atmospheric physics and chemistry, solid rocket propulsion, liquid rocket propulsion, government, and environmental agencies, and representatives from several responsible environmental organizations. The conclusion from this workshop relative to stratospheric ozone depletion was that neither solid nor liquid rocket launchers have a significant impact on stratospheric ozone depletion, and that there is no real significant difference between the two

  7. Physical metrology of aerosols; Metrologie physique des aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Boulaud, D.; Vendel, J. [CEA Saclay, 91 - Gif-sur-Yvette (France). Inst. de Protection et de Surete Nucleaire

    1996-12-31

    The various detection and measuring methods for aerosols are presented, and their selection is related to aerosol characteristics (size range, concentration or mass range), thermo-hydraulic conditions (carrier fluid temperature, pressure and flow rate) and to the measuring system conditions (measuring frequency, data collection speed, cost...). Methods based on aerosol dynamic properties (inertial, diffusional and electrical methods) and aerosol optical properties (localized and integral methods) are described and their performances and applications are compared

  8. Aerosol-Induced Changes of Convective Cloud Anvils Produce Strong Climate Warming

    Science.gov (United States)

    Koren, I.; Remer, L. A.; Altaratz, O.; Martins, J. V.; Davidi, A.

    2010-01-01

    The effect of aerosol on clouds poses one of the largest uncertainties in estimating the anthropogenic contribution to climate change. Small human-induced perturbations to cloud characteristics via aerosol pathways can create a change in the top-of-atmosphere radiative forcing of hundreds of Wm(exp-2) . Here we focus on links between aerosol and deep convective clouds of the Atlantic and Pacific Intertropical Convergence Zones, noting that the aerosol environment in each region is entirely different. The tops of these vertically developed clouds consisting of mostly ice can reach high levels of the atmosphere, overshooting the lower stratosphere and reaching altitudes greater than 16 km. We show a link between aerosol, clouds and the free atmosphere wind profile that can change the magnitude and sign of the overall climate radiative forcing. We find that increased aerosol loading is associated with taller cloud towers and anvils. The taller clouds reach levels of enhanced wind speeds that act to spread and thin the anvi1 clouds, increasing areal coverage and decreasing cloud optical depth. The radiative effect of this transition is to create a positive radiative forcing (warming) at top-of-atmosphere. Furthermore we introduce the cloud optical depth (r), cloud height (Z) forcing space and show that underestimation of radiative forcing is likely to occur in cases of non homogenous clouds. Specifically, the mean radiative forcing of towers and anvils in the same scene can be several times greater than simply calculating the forcing from the mean cloud optical depth in the scene. Limitations of the method are discussed, alternative sources of aerosol loading are tested and meteorological variance is restricted, but the trend of taller clouds; increased and thinner anvils associated with increased aerosol loading remains robust through all the different tests and perturbations.

  9. Aerosol-induced changes of convective cloud anvils produce strong climate warming

    Directory of Open Access Journals (Sweden)

    I. Koren

    2010-05-01

    Full Text Available The effect of aerosol on clouds poses one of the largest uncertainties in estimating the anthropogenic contribution to climate change. Small human-induced perturbations to cloud characteristics via aerosol pathways can create a change in the top-of-atmosphere radiative forcing of hundreds of Wm−2. Here we focus on links between aerosol and deep convective clouds of the Atlantic and Pacific Intertropical Convergence Zones, noting that the aerosol environment in each region is entirely different. The tops of these vertically developed clouds consisting of mostly ice can reach high levels of the atmosphere, overshooting the lower stratosphere and reaching altitudes greater than 16 km. We show a link between aerosol, clouds and the free atmosphere wind profile that can change the magnitude and sign of the overall climate radiative forcing.

    We find that increased aerosol loading is associated with taller cloud towers and anvils. The taller clouds reach levels of enhanced wind speeds that act to spread and thin the anvil clouds, increasing areal coverage and decreasing cloud optical depth. The radiative effect of this transition is to create a positive radiative forcing (warming at top-of-atmosphere.

    Furthermore we introduce the cloud optical depth (τ, cloud height (Z forcing space and show that underestimation of radiative forcing is likely to occur in cases of non homogenous clouds. Specifically, the mean radiative forcing of towers and anvils in the same scene can be several times greater than simply calculating the forcing from the mean cloud optical depth in the scene.

    Limitations of the method are discussed, alternative sources of aerosol loading are tested and meteorological variance is restricted, but the trend of taller clouds, increased and thinner anvils associated with increased aerosol loading remains robust through all the different tests and perturbations.

  10. The aerosols and the greenhouse effect; Aerosoler og klimaeffekten

    Energy Technology Data Exchange (ETDEWEB)

    Iversen, Trond; Kirkevaag, Alf; Seland, Oeyvind; Debernard, Jens Boldingh; Kristjansson, Jon Egill; Storelvmo, Trude

    2008-07-01

    The article discussed the aerosol effects on the climatic changes and points out that the climate models do not incorporate these components satisfactorily mostly due to insufficient knowledge of the aerosol pollution sources. The direct and indirect effects of aerosols are mentioned as well as the climate response (tk)

  11. Airborne UV DIAL Measurements of Ozone and Aerosols

    Science.gov (United States)

    Grant, William B.; Browell, Edward V.

    2000-01-01

    The NASA Langley Research Center's airborne UV Differential Absorption Lidar (DIAL) system measures vertical profiles of ozone and aerosols above and below the aircraft along its flight track. This system has been used in over 20 airborne field missions designed to study the troposphere and stratosphere since 1980. Four of these missions involved tropospheric measurement programs in the Pacific Ocean with two in the western North Pacific and two in the South Pacific. The UV DIAL system has been used in these missions to study such things as pollution outflow, long-range transport, and stratospheric intrusions; categorize the air masses encountered; and to guide the aircraft to altitudes where interesting features can be studied using the in situ instruments. This paper will highlight the findings with the UV DIAL system in the Pacific Ocean field programs and introduce the mission planned for the western North Pacific for February-April 2001. This will be an excellent opportunity for collaboration between the NASA airborne mission and those with ground-based War systems in Asia Pacific Rim countries to make a more complete determination of the transport of air from Asia to the western Pacific.

  12. Direct stratospheric injection of biomass burning emissions: a case study of the 2009 Australian bushfires using the NASA GISS ModelE2 composition-climate model

    Science.gov (United States)

    Field, Robert; From, Mike; Voulgarakis, Apostolos; Shindell, Drew; Flannigan, Mike; Bernath, Peter

    2014-05-01

    Direct stratospheric injection (DSI) of forest fire smoke represents a direct biogeochemical link between the land surface and stratosphere. DSI events occur regularly in the northern and southern extratropics, and have been observed across a wide range of measurements, but their fate and effects are not well understood. DSIs result from explosive, short-lived fires, and their plumes stand out from background concentrations immediately. This makes it easier to associate detected DSIs to individual fires and their estimated emissions. Because the emissions pulses are brief, chemical decay can be more clearly assessed, and because the emissions pulses are so large, a wide range of rare chemical species can be detected. Observational evidence suggests that they can persist in the stratosphere for several months, enhance ozone production, and be self-lofted to the middle stratosphere through shortwave absorption and diabatic heating. None of these phenomena have been evaluated, however, with a physical model. To that end, we are simulating the smoke plumes from the February 2009 Australia 'Black Saturday' bushfires using the NASA GISS ModelE2 composition-climate model, nudged toward horizontal winds from reanalysis. To-date, this is the best-observed DSI in the southern hemisphere. Chemical and aerosol signatures of the plume were observed in a wide array of limb and nadir satellite retrievals. Detailed estimates of fuel consumption and injection height have been made because of the severity of the fires. Uncommon among DSIs events was a large segment of the plume that entrained into the upper equatorial easterlies. Preliminary modeling results show that the relative strengths of the equatorial and extratropical plume segments are sensitive to the plume's initial injection height. This highlights the difficulty in reconciling uncertainty in the reanalysis over the Southern Hemisphere with fairly-well constrained estimates of fire location and injection height at the

  13. Investigating the Use of a Simplified Aerosol Parameterization in Space-Based XCO2 Retrievals from OCO-2

    Science.gov (United States)

    Nelson, R. R.; O'Dell, C.

    2017-12-01

    The primary goal of OCO-2 is to use hyperspectral measurements of reflected near-infrared sunlight to retrieve the column-averaged dry-air mole fraction of carbon dioxide (XCO2) with high accuracy. This is only possible for measurements of scenes nearly free of optically thick clouds and aerosols. As some cloud or aerosol contamination will always be present, the OCO-2 retrieval algorithm includes clouds and aerosols as retrieved properties in its state vector. Information content analyses demonstrate that there are only 2-6 pieces of information about aerosols in the OCO-2 radiances. However, the upcoming OCO-2 algorithm (B8) attempts to retrieve 9 aerosol parameters; this over-fitting can hinder convergence and produce multiple solutions. In this work, we develop a simplified cloud and aerosol parameterization that intelligently reduces the number of retrieved parameters to 5 by only retrieving information about two aerosol layers: a lower tropospheric layer and an upper tropospheric / stratospheric layer. We retrieve the optical depth of each layer and the height of the lower tropospheric layer. Each of these layers contains a mixture of fine and coarse mode aerosol. In comparisons between OCO-2 XCO2 estimates and validation sources including TCCON, this scheme performs about as well as the more complicated OCO-2 retrieval algorithm, but has the potential benefits of more interpretable aerosol results, faster convergence, less nonlinearity, and greater throughput. We also investigate the dependence of our results on the optical properties of the fine and coarse mode aerosol types, such as their effective radii and the environmental relative humidity.

  14. Titan's Tropopause Temperatures from CIRS: Implications for Stratospheric Methane Cloud Formation

    Science.gov (United States)

    Anderson, C. M.; Samuelson, R. E.; Achterberg, R. K.; Barnes, J. W.; Flasar, F. M.

    2012-01-01

    Analysis of Cassini Composite Infrared Spectrometer (CIRS) far-IR spectra enable the construction of Titan's temperature profile in the altitude region containing the tropopause. Whereas the methane V4 band at 1306/cm (7.7 microns) is the primary opacity source for deducing thermal structure between 100 km and 500 km, N2-N2 collision-induced absorption between 70 and 140/cm (143 microns and 71 microns) is utilized to determine temperatures at Titan's tropopause. Additional opacity due to aerosol and nitrile ices must also be taken into account in this part of the far-IR spectral region. The spectral characteristics of these particulate opacities have been deduced from CIRS limb data at 58degS, 15degS, 15degN, and 85degN. Empirically, the spectral shapes of these opacities appear to be independent of both latitude and altitude below 300 km (Anderson and Samuelson, 2011, Icarus 212, 762-778), justifying the extension of these spectral properties to all latitudes. We find that Titan's tropopause temperature is cooler than the HAS! value of 70.5K by approx. 6K. This leads to the possibility that subsidence at high northern latitudes can cause methane condensation in the winter polar stratosphere. A search for methane clouds in this region is in progress.

  15. Chemical and climatic drivers of radiative forcing due to changes in stratospheric and tropospheric ozone over the 21st century

    Directory of Open Access Journals (Sweden)

    A. Banerjee

    2018-02-01

    Full Text Available The ozone radiative forcings (RFs resulting from projected changes in climate, ozone-depleting substances (ODSs, non-methane ozone precursor emissions and methane between the years 2000 and 2100 are calculated using simulations from the UM-UKCA chemistry–climate model (UK Met Office's Unified Model containing the United Kingdom Chemistry and Aerosols sub-model. Projected measures to improve air-quality through reductions in non-methane tropospheric ozone precursor emissions present a co-benefit for climate, with a net global mean ozone RF of −0.09 W m−2. This is opposed by a positive ozone RF of 0.05 W m−2 due to future decreases in ODSs, which is driven by an increase in tropospheric ozone through stratosphere-to-troposphere transport of air containing higher ozone amounts. An increase in methane abundance by more than a factor of 2 (as projected by the RCP8.5 scenario is found to drive an ozone RF of 0.18 W m−2, which would greatly outweigh the climate benefits of non-methane tropospheric ozone precursor reductions. A small fraction (∼ 15 % of the ozone RF due to the projected increase in methane results from increases in stratospheric ozone. The sign of the ozone RF due to future changes in climate (including the radiative effects of greenhouse gases, sea surface temperatures and sea ice changes is shown to be dependent on the greenhouse gas emissions pathway, with a positive RF (0.05 W m−2 for RCP4.5 and a negative RF (−0.07 W m−2 for the RCP8.5 scenario. This dependence arises mainly from differences in the contribution to RF from stratospheric ozone changes. Considering the increases in tropopause height under climate change causes only small differences (≤ |0.02| W m−2 for the stratospheric, tropospheric and whole-atmosphere RFs.

  16. Stable generator of polydisperse aerosol

    Czech Academy of Sciences Publication Activity Database

    Mikuška, Pavel

    2001-01-01

    Roč. 32, Suppl. 1 (2001), s. S823-S824 ISSN 0021-8502. [European Aerosol Conference 2001. Leipzig, 03.09.2001-07.09.2001] R&D Projects: GA AV ČR IAA4031105 Institutional research plan: CEZ:AV0Z4031919 Keywords : aerosol generator * fine aerosol * polydisperse aerosol Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.605, year: 2001

  17. Potential of secondary aerosol formation from Chinese gasoline engine exhaust.

    Science.gov (United States)

    Du, Zhuofei; Hu, Min; Peng, Jianfei; Guo, Song; Zheng, Rong; Zheng, Jing; Shang, Dongjie; Qin, Yanhong; Niu, He; Li, Mengren; Yang, Yudong; Lu, Sihua; Wu, Yusheng; Shao, Min; Shuai, Shijin

    2018-04-01

    Light-duty gasoline vehicles have drawn public attention in China due to their significant primary emissions of particulate matter and volatile organic compounds (VOCs). However, little information on secondary aerosol formation from exhaust for Chinese vehicles and fuel conditions is available. In this study, chamber experiments were conducted to quantify the potential of secondary aerosol formation from the exhaust of a port fuel injection gasoline engine. The engine and fuel used are common in the Chinese market, and the fuel satisfies the China V gasoline fuel standard. Substantial secondary aerosol formation was observed during a 4-5hr simulation, which was estimated to represent more than 10days of equivalent atmospheric photo-oxidation in Beijing. As a consequence, the extreme case secondary organic aerosol (SOA) production was 426±85mg/kg-fuel, with high levels of precursors and OH exposure. The low hygroscopicity of the aerosols formed inside the chamber suggests that SOA was the dominant chemical composition. Fourteen percent of SOA measured in the chamber experiments could be explained through the oxidation of speciated single-ring aromatics. Unspeciated precursors, such as intermediate-volatility organic compounds and semi-volatile organic compounds, might be significant for SOA formation from gasoline VOCs. We concluded that reductions of emissions of aerosol precursor gases from vehicles are essential to mediate pollution in China. Copyright © 2017. Published by Elsevier B.V.

  18. Extreme events in total ozone over Arosa – Part 1: Application of extreme value theory

    Directory of Open Access Journals (Sweden)

    H. E. Rieder

    2010-10-01

    Full Text Available In this study ideas from extreme value theory are for the first time applied in the field of stratospheric ozone research, because statistical analysis showed that previously used concepts assuming a Gaussian distribution (e.g. fixed deviations from mean values of total ozone data do not adequately address the structure of the extremes. We show that statistical extreme value methods are appropriate to identify ozone extremes and to describe the tails of the Arosa (Switzerland total ozone time series. In order to accommodate the seasonal cycle in total ozone, a daily moving threshold was determined and used, with tools from extreme value theory, to analyse the frequency of days with extreme low (termed ELOs and high (termed EHOs total ozone at Arosa. The analysis shows that the Generalized Pareto Distribution (GPD provides an appropriate model for the frequency distribution of total ozone above or below a mathematically well-defined threshold, thus providing a statistical description of ELOs and EHOs. The results show an increase in ELOs and a decrease in EHOs during the last decades. The fitted model represents the tails of the total ozone data set with high accuracy over the entire range (including absolute monthly minima and maxima, and enables a precise computation of the frequency distribution of ozone mini-holes (using constant thresholds. Analyzing the tails instead of a small fraction of days below constant thresholds provides deeper insight into the time series properties. Fingerprints of dynamical (e.g. ENSO, NAO and chemical features (e.g. strong polar vortex ozone loss, and major volcanic eruptions, can be identified in the observed frequency of extreme events throughout the time series. Overall the new approach to analysis of extremes provides more information on time series properties and variability than previous approaches that use only monthly averages and/or mini-holes and mini-highs.

  19. Extremely Preterm Birth

    Science.gov (United States)

    ... Events Advocacy For Patients About ACOG Extremely Preterm Birth Home For Patients Search FAQs Extremely Preterm Birth ... Spanish FAQ173, June 2016 PDF Format Extremely Preterm Birth Pregnancy When is a baby considered “preterm” or “ ...

  20. Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in situ and satellite observations

    Science.gov (United States)

    Lurton, Thibaut; Jégou, Fabrice; Berthet, Gwenaël; Renard, Jean-Baptiste; Clarisse, Lieven; Schmidt, Anja; Brogniez, Colette; Roberts, Tjarda J.

    2018-03-01

    Volcanic eruptions impact climate through the injection of sulfur dioxide (SO2), which is oxidized to form sulfuric acid aerosol particles that can enhance the stratospheric aerosol optical depth (SAOD). Besides large-magnitude eruptions, moderate-magnitude eruptions such as Kasatochi in 2008 and Sarychev Peak in 2009 can have a significant impact on stratospheric aerosol and hence climate. However, uncertainties remain in quantifying the atmospheric and climatic impacts of the 2009 Sarychev Peak eruption due to limitations in previous model representations of volcanic aerosol microphysics and particle size, whilst biases have been identified in satellite estimates of post-eruption SAOD. In addition, the 2009 Sarychev Peak eruption co-injected hydrogen chloride (HCl) alongside SO2, whose potential stratospheric chemistry impacts have not been investigated to date. We present a study of the stratospheric SO2-particle-HCl processing and impacts following Sarychev Peak eruption, using the Community Earth System Model version 1.0 (CESM1) Whole Atmosphere Community Climate Model (WACCM) - Community Aerosol and Radiation Model for Atmospheres (CARMA) sectional aerosol microphysics model (with no a priori assumption on particle size). The Sarychev Peak 2009 eruption injected 0.9 Tg of SO2 into the upper troposphere and lower stratosphere (UTLS), enhancing the aerosol load in the Northern Hemisphere. The post-eruption evolution of the volcanic SO2 in space and time are well reproduced by the model when compared to Infrared Atmospheric Sounding Interferometer (IASI) satellite data. Co-injection of 27 Gg HCl causes a lengthening of the SO2 lifetime and a slight delay in the formation of aerosols, and acts to enhance the destruction of stratospheric ozone and mono-nitrogen oxides (NOx) compared to the simulation with volcanic SO2 only. We therefore highlight the need to account for volcanic halogen chemistry when simulating the impact of eruptions such as Sarychev on

  1. Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in situ and satellite observations

    Directory of Open Access Journals (Sweden)

    T. Lurton

    2018-03-01

    Full Text Available Volcanic eruptions impact climate through the injection of sulfur dioxide (SO2, which is oxidized to form sulfuric acid aerosol particles that can enhance the stratospheric aerosol optical depth (SAOD. Besides large-magnitude eruptions, moderate-magnitude eruptions such as Kasatochi in 2008 and Sarychev Peak in 2009 can have a significant impact on stratospheric aerosol and hence climate. However, uncertainties remain in quantifying the atmospheric and climatic impacts of the 2009 Sarychev Peak eruption due to limitations in previous model representations of volcanic aerosol microphysics and particle size, whilst biases have been identified in satellite estimates of post-eruption SAOD. In addition, the 2009 Sarychev Peak eruption co-injected hydrogen chloride (HCl alongside SO2, whose potential stratospheric chemistry impacts have not been investigated to date. We present a study of the stratospheric SO2–particle–HCl processing and impacts following Sarychev Peak eruption, using the Community Earth System Model version 1.0 (CESM1 Whole Atmosphere Community Climate Model (WACCM – Community Aerosol and Radiation Model for Atmospheres (CARMA sectional aerosol microphysics model (with no a priori assumption on particle size. The Sarychev Peak 2009 eruption injected 0.9 Tg of SO2 into the upper troposphere and lower stratosphere (UTLS, enhancing the aerosol load in the Northern Hemisphere. The post-eruption evolution of the volcanic SO2 in space and time are well reproduced by the model when compared to Infrared Atmospheric Sounding Interferometer (IASI satellite data. Co-injection of 27 Gg HCl causes a lengthening of the SO2 lifetime and a slight delay in the formation of aerosols, and acts to enhance the destruction of stratospheric ozone and mono-nitrogen oxides (NOx compared to the simulation with volcanic SO2 only. We therefore highlight the need to account for volcanic halogen chemistry when simulating the impact of eruptions

  2. A unified approach to infrared aerosol remote sensing and type specification

    Directory of Open Access Journals (Sweden)

    L. Clarisse

    2013-02-01

    Full Text Available Atmospheric aerosols impact air quality and global climate. Space based measurements are the best way to observe their spatial and temporal distributions, and can also be used to gain better understanding of their chemical, physical and optical properties. Aerosol composition is the key parameter affecting the refractive index, which determines how much radiation is scattered and absorbed. Composition of aerosols is unfortunately not measured by state of the art satellite remote sounders. Here we use high resolution infrared measurements for aerosol type differentiation, exploiting, in that part of spectrum, the dependency of their refractive index on wavelength. We review existing detection methods and present a unified detection method based on linear discrimination analysis. We demonstrate this method on measurements of the Infrared Atmospheric Sounding Interferometer (IASI and five different aerosol types, namely volcanic ash, windblown sand, sulfuric acid droplets, ammonium sulfate and smoke particles. We compare these with traditional MODIS AOD measurements. The detection of the last three types is unprecedented in the infrared in nadir mode, but is very promising, especially for sulfuric acid droplets which are detected in the lower troposphere and up to 6 months after injection in the upper troposphere/lower stratosphere.

  3. Air Revitalization System Enables Excursions to the Stratosphere

    Science.gov (United States)

    2015-01-01

    Paragon Space Development Corporation, based in Tucson, Arizona has had a long history of collaboration with NASA, including developing a modular air purification system under the Commercial Crew Development Program, designed to support the commercial space sector. Using that device and other NASA technology, startup company World View is now gearing up to take customers on helium balloon rides to the stratosphere.

  4. An ultrahot gas-giant exoplanet with a stratosphere.

    Science.gov (United States)

    Evans, Thomas M; Sing, David K; Kataria, Tiffany; Goyal, Jayesh; Nikolov, Nikolay; Wakeford, Hannah R; Deming, Drake; Marley, Mark S; Amundsen, David S; Ballester, Gilda E; Barstow, Joanna K; Ben-Jaffel, Lotfi; Bourrier, Vincent; Buchhave, Lars A; Cohen, Ofer; Ehrenreich, David; García Muñoz, Antonio; Henry, Gregory W; Knutson, Heather; Lavvas, Panayotis; Etangs, Alain Lecavelier des; Lewis, Nikole K; López-Morales, Mercedes; Mandell, Avi M; Sanz-Forcada, Jorge; Tremblin, Pascal; Lupu, Roxana

    2017-08-02

    Infrared radiation emitted from a planet contains information about the chemical composition and vertical temperature profile of its atmosphere. If upper layers are cooler than lower layers, molecular gases will produce absorption features in the planetary thermal spectrum. Conversely, if there is a stratosphere-where temperature increases with altitude-these molecular features will be observed in emission. It has been suggested that stratospheres could form in highly irradiated exoplanets, but the extent to which this occurs is unresolved both theoretically and observationally. A previous claim for the presence of a stratosphere remains open to question, owing to the challenges posed by the highly variable host star and the low spectral resolution of the measurements. Here we report a near-infrared thermal spectrum for the ultrahot gas giant WASP-121b, which has an equilibrium temperature of approximately 2,500 kelvin. Water is resolved in emission, providing a detection of an exoplanet stratosphere at 5σ confidence. These observations imply that a substantial fraction of incident stellar radiation is retained at high altitudes in the atmosphere, possibly by absorbing chemical species such as gaseous vanadium oxide and titanium oxide.

  5. Chlorine activation and ozone destruction in the northern lowermost stratosphere

    NARCIS (Netherlands)

    Lelieveld, J; Bregman, A; Scheeren, HA; Strom, J; Carslaw, KS; Fischer, H; Siegmund, PC; Arnold, F

    1999-01-01

    We report aircraft measurements from the Stratosphere-Troposphere Experiments by Aircraft Measurements (STREAM) II campaign, performed during February 1995 from Kiruna, northern Sweden, near 67 degrees N latitude. We have measured trace species, e.g., O-3, nitrogen compounds, HCl, hydrocarbons, CO,

  6. Stratospheric Ozone Reactive Chemicals Generated by Space Launches Worldwide.

    Science.gov (United States)

    1994-11-01

    I ODCs). Their carbon - chlorine bond is severed in the stratosphere by solar photolysis or reaction. Once the carbon-chlorine bond is broken, the...include the Russian Proton and Energia , and the Chinese Long March series. Roughly half (seven per year) of the Ariane 4 launches use two solid strap-ons

  7. Tritium Records to Trace Stratospheric Moisture Inputs in Antarctica

    Science.gov (United States)

    Fourré, E.; Landais, A.; Cauquoin, A.; Jean-Baptiste, P.; Lipenkov, V.; Petit, J.-R.

    2018-03-01

    Better assessing the dynamic of stratosphere-troposphere exchange is a key point to improve our understanding of the climate dynamic in the East Antarctica Plateau, a region where stratospheric inputs are expected to be important. Although tritium (3H or T), a nuclide naturally produced mainly in the stratosphere and rapidly entering the water cycle as HTO, seems a first-rate tracer to study these processes, tritium data are very sparse in this region. We present the first high-resolution measurements of tritium concentration over the last 50 years in three snow pits drilled at the Vostok station. Natural variability of the tritium records reveals two prominent frequencies, one at about 10 years (to be related to the solar Schwabe cycles) and the other one at a shorter periodicity: despite dating uncertainty at this short scale, a good correlation is observed between 3H and Na+ and an anticorrelation between 3H and δ18O measured on an individual pit. The outputs from the LMDZ Atmospheric General Circulation Model including stable water isotopes and tritium show the same 3H-δ18O anticorrelation and allow further investigation on the associated mechanism. At the interannual scale, the modeled 3H variability matches well with the Southern Annular Mode index. At the seasonal scale, we show that modeled stratospheric tritium inputs in the troposphere are favored in winter cold and dry conditions.

  8. UV spectroscopy applied to stratospheric chemistry, methods and results

    Energy Technology Data Exchange (ETDEWEB)

    Karlsen, K.

    1996-03-01

    The publication from the Norwegian Institute for Air Research (NILU) deals with an investigation done on stratospheric chemistry by UV spectroscopy. The scientific goals are briefly discussed, and it gives the results from the measuring and analysing techniques used in the investigation. 6 refs., 11 figs.

  9. Unintended consequences of atmospheric injection of sulphate aerosols.

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Patrick Vane; Kobos, Peter Holmes; Goldstein, Barry

    2010-10-01

    Most climate scientists believe that climate geoengineering is best considered as a potential complement to the mitigation of CO{sub 2} emissions, rather than as an alternative to it. Strong mitigation could achieve the equivalent of up to -4Wm{sup -2} radiative forcing on the century timescale, relative to a worst case scenario for rising CO{sub 2}. However, to tackle the remaining 3Wm{sup -2}, which are likely even in a best case scenario of strongly mitigated CO{sub 2} releases, a number of geoengineering options show promise. Injecting stratospheric aerosols is one of the least expensive and, potentially, most effective approaches and for that reason an examination of the possible unintended consequences of the implementation of atmospheric injections of sulphate aerosols was made. Chief among these are: reductions in rainfall, slowing of atmospheric ozone rebound, and differential changes in weather patterns. At the same time, there will be an increase in plant productivity. Lastly, because atmospheric sulphate injection would not mitigate ocean acidification, another side effect of fossil fuel burning, it would provide only a partial solution. Future research should aim at ameliorating the possible negative unintended consequences of atmospheric injections of sulphate injection. This might include modeling the optimum rate and particle type and size of aerosol injection, as well as the latitudinal, longitudinal and altitude of injection sites, to balance radiative forcing to decrease negative regional impacts. Similarly, future research might include modeling the optimum rate of decrease and location of injection sites to be closed to reduce or slow rapid warming upon aerosol injection cessation. A fruitful area for future research might be system modeling to enhance the possible positive increases in agricultural productivity. All such modeling must be supported by data collection and laboratory and field testing to enable iterative modeling to increase the

  10. Aerosols, clouds and radiation

    Energy Technology Data Exchange (ETDEWEB)

    Twomey, S [University of Arizona, Tucson, AZ (USA). Inst. of Atmospheric Physics

    1991-01-01

    Most of the so-called 'CO{sub 2} effect' is, in fact, an 'H{sub 2}O effect' brought into play by the climate modeler's assumption that planetary average temperature dictates water-vapor concentration (following Clapeyron-Clausius). That assumption ignores the removal process, which cloud physicists know to be influenced by the aerosol, since the latter primarily controls cloud droplet number and size. Droplet number and size are also influential for shortwave (solar) energy. The reflectance of many thin to moderately thick clouds changes when nuclei concentrations change and make shortwave albedo susceptible to aerosol influence.

  11. Radon dose and aerosols

    International Nuclear Information System (INIS)

    Planinic, J.; Radolic, V.; Faj, Z.; Vukovic, B.

    2000-01-01

    The equilibrium factor value (F) was measured in the NRPB radon chamber and the corresponding track density ratio (r = D/D 0 ) of bare (D) and diffusion (D 0 ) LR-115 nuclear track detectors was determined, as well as the regression equation F(r). Experiments with LR-115 nuclear track detectors and aerosol sources (burning candle and cigarette) were carried out in the Osijek University radon chamber and afterwards an empirical relationship between the equilibrium factor and aerosol concentration was derived. For the purpose of radon dose equivalent assessment, procedures for determining the unattached fraction of radon progeny were introduced using two nuclear track detectors. (author)

  12. Quantifying pollution transport from the Asian monsoon anticyclone into the lower stratosphere

    Directory of Open Access Journals (Sweden)

    F. Ploeger

    2017-06-01

    Full Text Available Pollution transport from the surface to the stratosphere within the Asian monsoon circulation may cause harmful effects on stratospheric chemistry and climate. Here, we investigate air mass transport from the monsoon anticyclone into the stratosphere using a Lagrangian chemistry transport model. We show how two main transport pathways from the anticyclone emerge: (i into the tropical stratosphere (tropical pipe, and (ii into the Northern Hemisphere (NH extratropical lower stratosphere. Maximum anticyclone air mass fractions reach around 5 % in the tropical pipe and 15 % in the extratropical lowermost stratosphere over the course of a year. The anticyclone air mass fraction correlates well with satellite hydrogen cyanide (HCN and carbon monoxide (CO observations, confirming that pollution is transported deep into the tropical stratosphere from the Asian monsoon anticyclone. Cross-tropopause transport occurs in a vertical chimney, but with the pollutants transported quasi-horizontally along isentropes above the tropopause into the tropics and NH.

  13. Titan's Stratospheric Condensibles at High Northern Latitudes During Northern Winter

    Science.gov (United States)

    Anderson, Carrie; Samuelson, R.; Achterberg, R.

    2012-01-01

    The Infrared Interferometer Spectrometer (IRIS) instrument on board Voyager 1 caught the first glimpse of an unidentified particulate feature in Titan's stratosphere that spectrally peaks at 221 per centimeter. Until recently, this feature that we have termed 'the haystack,' has been seen persistently at high northern latitudes with the Composite Infrared Spectrometer (CIRS) instrument onboard Cassini, The strength of the haystack emission feature diminishes rapidly with season, becoming drastically reduced at high northern latitudes, as Titan transitions from northern winter into spring, In contrast to IRIS whose shortest wavenumber was 200 per centimeter, CIRS extends down to 10 per centimeter, thus revealing an entirely unexplored spectral region in which nitrile ices have numerous broad lattice vibration features, Unlike the haystack, which is only found at high northern latitudes during northern winter/early northern spring, this geometrically thin nitrile cloud pervades Titan's lower stratosphere, spectrally peaking at 160 per centimeter, and is almost global in extent spanning latitudes 85 N to 600 S, The inference of nitrile ices are consistent with the highly restricted altitude ranges over which these features are observed, and appear to be dominated by a mixture of HCN and HC3N, The narrow range in altitude over which the nitrile ices extend is unlike the haystack, whose vertical distribution is significantly broader, spanning roughly 70 kilometers in altitude in Titan's lower stratosphere, The nitrile clouds that CIRS observes are located in a dynamically stable region of Titan's atmosphere, whereas CH4 clouds, which ordinarily form in the troposphere, form in a more dynamically unstable region, where convective cloud systems tend to occur. In the unusual situation where Titan's tropopause cools significantly from the HASI 70.5K temperature minimum, CH4 should condense in Titan's lower stratosphere, just like the aforementioned nitrile clouds, although

  14. A refined method for calculating equivalent effective stratospheric chlorine

    Science.gov (United States)

    Engel, Andreas; Bönisch, Harald; Ostermöller, Jennifer; Chipperfield, Martyn P.; Dhomse, Sandip; Jöckel, Patrick

    2018-01-01

    Chlorine and bromine atoms lead to catalytic depletion of ozone in the stratosphere. Therefore the use and production of ozone-depleting substances (ODSs) containing chlorine and bromine is regulated by the Montreal Protocol to protect the ozone layer. Equivalent effective stratospheric chlorine (EESC) has been adopted as an appropriate metric to describe the combined effects of chlorine and bromine released from halocarbons on stratospheric ozone. Here we revisit the concept of calculating EESC. We derive a refined formulation of EESC based on an advanced concept of ODS propagation into the stratosphere and reactive halogen release. A new transit time distribution is introduced in which the age spectrum for an inert tracer is weighted with the release function for inorganic halogen from the source gases. This distribution is termed the release time distribution. We show that a much better agreement with inorganic halogen loading from the chemistry transport model TOMCAT is achieved compared with using the current formulation. The refined formulation shows EESC levels in the year 1980 for the mid-latitude lower stratosphere, which are significantly lower than previously calculated. The year 1980 is commonly used as a benchmark to which EESC must return in order to reach significant progress towards halogen and ozone recovery. Assuming that - under otherwise unchanged conditions - the EESC value must return to the same level in order for ozone to fully recover, we show that it will take more than 10 years longer than estimated in this region of the stratosphere with the current method for calculation of EESC. We also present a range of sensitivity studies to investigate the effect of changes and uncertainties in the fractional release factors and in the assumptions on the shape of the release time distributions. We further discuss the value of EESC as a proxy for future evolution of inorganic halogen loading under changing atmospheric dynamics using simulations from

  15. Phase function, backscatter, extinction, and absorption for standard radiation atmosphere and El Chichon aerosol models at visible and near-infrared wavelengths

    Science.gov (United States)

    Whitlock, C. H.; Suttles, J. T.; Lecroy, S. R.

    1985-01-01

    Tabular values of phase function, Legendre polynominal coefficients, 180 deg backscatter, and extinction cross section are given for eight wavelengths in the atmospheric windows between 0.4 and 2.2 microns. Also included are single scattering albedo, asymmetry factor, and refractive indices. These values are based on Mie theory calculations for the standard rediation atmospheres (continental, maritime, urban, unperturbed stratospheric, volcanic, upper atmospheric, soot, oceanic, dust, and water-soluble) assest measured volcanic aerosols at several time intervals following the El Chichon eruption. Comparisons of extinction to 180 deg backscatter for different aerosol models are presented and related to lidar data.

  16. Atmospheric aerosol system: An overview

    International Nuclear Information System (INIS)

    Prospero, J.M.; Charlson, R.J.; Mohnen, V.; Jaenicke, R.; Delany, A.C.; Moyers, J.; Zoller, W.; Rahn, K.

    1983-01-01

    Aerosols could play a critical role in many processes which impact on our lives either indirectly (e.g., climate) or directly (e.g., health). However, our ability to assess these possible impacts is constrained by our limited knowledge of the physical and chemical properties of aerosols, both anthropogenic and natural. This deficiency is attributable in part to the fact that aerosols are the end product of a vast array of chemical and physical processes. Consequently, the properties of the aerosol can exhibit a great deal of variability in both time and space. Furthermore, most aerosol studies have focused on measurements of a single aerosol characteristic such as composition or size distribution. Such information is generally not useful for the assessment of impacts because the degree of impact may depend on the integral properties of the aerosol, for example, the aerosol composition as a function of particle size. In this overview we discuss recent work on atmospheric aerosols that illustrates the complex nature of the aerosol chemical and physical system, and we suggest strategies for future research. A major conclusion is that man has had a great impact on the global budgets of certain species, especially sulfur and nitrogen, that play a dominant role in the atmospheric aerosol system. These changes could conceivably affect climate. Large-scale impacts are implied because it has recently been demonstrated that natural and pollutant aerosol episodes can be propagated over great distances. However, at present there is no evidence linking anthropogenic activities with a persistent increase in aerosol concentrations on a global scale. A major problem in assessing man's impact on the atmospheric aerosol system and on global budgets is the absence of aerosol measurements in remote marine and continental areas

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

    Science.gov (United States)

    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

  18. Solar wind control of stratospheric temperatures in Jupiter's auroral regions?

    Science.gov (United States)

    Sinclair, James Andrew; Orton, Glenn; Kasaba, Yasumasa; Sato, Takao M.; Tao, Chihiro; Waite, J. Hunter; Cravens, Thomas; Houston, Stephen; Fletcher, Leigh; Irwin, Patrick; Greathouse, Thomas K.

    2017-10-01

    Auroral emissions are the process through which the interaction of a planet’s atmosphere and its external magnetosphere can be studied. Jupiter exhibits auroral emission at a multitude of wavelengths including the X-ray, ultraviolet and near-infrared. Enhanced emission of CH4 and other stratospheric hydrocarbons is also observed coincident with Jupiter’s shorter-wavelength auroral emission (e.g. Caldwell et al., 1980, Icarus 44, 667-675, Kostiuk et al., 1993, JGR 98, 18823). This indicates that auroral processes modify the thermal structure and composition of the auroral stratosphere. The exact mechanism responsible for this auroral-related heating of the stratosphere has however remained elusive (Sinclair et al., 2017a, Icarus 292, 182-207, Sinclair et al., 2017b, GRL, 44, 5345-5354). We will present an analysis of 7.8-μm images of Jupiter measured by COMICS (Cooled Mid-Infrared Camera and Spectrograph, Kataza et al., 2000, Proc. SPIE(4008), 1144-1152) on the Subaru telescope. These images were acquired on January 11th, 12th, 13th, 14th, February 4, 5th and May 17th, 18th, 19th and 20th in 2017, allowing the daily variability of Jupiter’s auroral-related stratospheric heating to be tracked. Preliminary results suggest lower stratospheric temperatures are directly forced by the solar wind dynamical pressure. The southern auroral hotspot exhibited a significant increase in brightness temperature over a 24-hour period. Over the same time period, a solar wind propagation model (Tao et al. 2005, JGR 110, A11208) predicts a strong increase in the solar wind dynamical pressure at Jupiter.

  19. GRIP LANGLEY AEROSOL RESEARCH GROUP EXPERIMENT (LARGE) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — Langley Aerosol Research Group Experiment (LARGE) measures ultrafine aerosol number density, total and non-volatile aerosol number density, dry aerosol size...

  20. Major Optical Depth Perturbations to the Stratosphere from Volcanic Eruptions: Stellar-Extinction Period, 1961-1978

    Science.gov (United States)

    Stothers, Richard B.; Hansen, James E. (Technical Monitor)

    2001-01-01

    A revised chronology of stratospheric aerosol extinction due to volcanic eruptions has been assembled for the period 1961-1978, which immediately precedes the era of dedicated satellite measurements. On the whole, the most accurate data consist of published observations of stellar extinction, supplemented in part by other kinds of observational data. The period covered encompasses the important eruptions of Agung (1963) and Fuego (1974), whose dust veils are discussed with respect to their transport, decay, and total mass. The effective (area-weighted mean) radii of the aerosols for both eruptions are found to be 0.3-0.4 microns. It is confirmed that, among known tropical eruptions, Agung's dust was unique for a low-latitude eruption in remaining almost entirely confined to the hemisphere of its production. A new table of homogeneous visual optical depth perturbations, listed by year and by hemisphere, is provided for the whole period 1881-1978, including the pyrheliometric period before 1961 that was investigated previously.

  1. Gondola development for CNES stratospheric balloons

    Science.gov (United States)

    Vargas, A.; Audoubert, J.; Cau, M.; Evrard, J.; Verdier, N.

    (over the line of sight) than with dedicated RF system, which requires balloon visibility from the ground station. For long duration flights (3 months) of Infra Red Montgolfieres, a house keeping gondola has been developed, using the Inmarsat C standard to have communication all around the world (up to N or S 80 ° latitude) with an automatic switching between the 4 geostationnary Inmarsat satellites. After validation flights performed from Bauru / Brazil. (2000 & 2001) and Kiruna/Sweden (2002), the first operational flights took place from Bauru in February 2003 during ENVISAT validation campaign. The next flights will be realized in the framework of the Hibiscus campaign planned in February 2004 in Bauru.. The Balloon Division was involved in the Franco / Japanese HSFD II project which consists to drop a mock-up of the Japanese HOPE-X space shuttle from a stratospheric balloon to validate its flight from the altitude of 30 km. We developed a specific gondola as a service module for the HOPE-X shuttle, providing power and GPS radio-frequency signal during the balloon flight phase, telemetry end remote control radio frequency links and separation system with pyrotechnic cutters for the drop of the shuttle. A successful flight was performed at Kiruna in July 2003. Concerning gondola with pointing system, the study of a big g-ray telescope (8 m of focal length), started by the end of 2002. For this 1 ton gondola, the telescope stabilization system will be based on control moment gyro (CMG). The CMG system has been designed and will be manufactured and validated during 2004. The first flight of this g-ray gondola is planned for 2006. The progress, status and future plans concerning these gondola developments will be presented.

  2. Composition and evolution of volcanic aerosol from eruptions of Kasatochi, Sarychev and Eyjafjallajökull in 2008–2010 based on CARIBIC observations

    Directory of Open Access Journals (Sweden)

    S. M. Andersson

    2013-02-01

    Full Text Available Large volcanic eruptions impact significantly on climate and lead to ozone depletion due to injection of particles and gases into the stratosphere where their residence times are long. In this the composition of volcanic aerosol is an important but inadequately studied factor. Samples of volcanically influenced aerosol were collected following the Kasatochi (Alaska, Sarychev (Russia and also during the Eyjafjallajökull (Iceland eruptions in the period 2008–2010. Sampling was conducted by the CARIBIC platform during regular flights at an altitude of 10–12 km as well as during dedicated flights through the volcanic clouds from the eruption of Eyjafjallajökull in spring 2010. Elemental concentrations of the collected aerosol were obtained by accelerator-based analysis. Aerosol from the Eyjafjallajökull volcanic clouds was identified by high concentrations of sulphur and elements pointing to crustal origin, and confirmed by trajectory analysis. Signatures of volcanic influence were also used to detect volcanic aerosol in stratospheric samples collected following the Sarychev and Kasatochi eruptions. In total it was possible to identify 17 relevant samples collected between 1 and more than 100 days following the eruptions studied. The volcanically influenced aerosol mainly consisted of ash, sulphate and included a carbonaceous component. Samples collected in the volcanic cloud from Eyjafjallajökull were dominated by the ash and sulphate component (∼45% each while samples collected in the tropopause region and LMS mainly consisted of sulphate (50–77% and carbon (21–43%. These fractions were increasing/decreasing with the age of the aerosol. Because of the long observation period, it was possible to analyze the evolution of the relationship between the ash and sulphate components of the volcanic aerosol. From this analysis the residence time (1/e of sulphur dioxide in the studied volcanic cloud was estimated to be 45 ± 22 days.

  3. Convectively Driven Tropopause-Level Cooling and Its Influences on Stratospheric Moisture

    Science.gov (United States)

    Kim, Joowan; Randel, William J.; Birner, Thomas

    2018-01-01

    Characteristics of the tropopause-level cooling associated with tropical deep convection are examined using CloudSat radar and Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) GPS radio occultation measurements. Extreme deep convection is sampled based on the cloud top height (>17 km) from CloudSat, and colocated temperature profiles from COSMIC are composited around the deep convection. Response of moisture to the tropopause-level cooling is also examined in the upper troposphere and lower stratosphere using microwave limb sounder measurements. The composite temperature shows an anomalous warming in the troposphere and a significant cooling near the tropopause (at 16-19 km) when deep convection occurs over the western Pacific, particularly during periods with active Madden-Julian Oscillation (MJO). The composite of the tropopause cooling has a large horizontal scale ( 6,000 km in longitude) with minimum temperature anomaly of -2 K, and it lasts more than 2 weeks with support of mesoscale convective clusters embedded within the envelope of the MJO. The water vapor anomalies show strong correlation with the temperature anomalies (i.e., dry anomaly in the cold anomaly), showing that the convectively driven tropopause cooling actively dehydrate the lower stratosphere in the western Pacific region. The moisture is also affected by anomalous Matsuno-Gill-type circulation associated with the cold anomaly, in which dry air spreads over a wide range in the tropical tropopause layer (TTL). These results suggest that convectively driven tropopause cooling and associated transient circulation play an important role in the large-scale dehydration process in the TTL.

  4. Lessons learned and way forward from 6 years of Aerosol_cci

    Science.gov (United States)

    Popp, Thomas; de Leeuw, Gerrit; Pinnock, Simon

    2017-04-01

    Within the ESA Climate Change Initiative (CCI) Aerosol_cci (2010 - 2017) conducts intensive work to improve and qualify algorithms for the retrieval of aerosol information from European sensors. Meanwhile, several validated (multi-) decadal time series of different aerosol parameters from complementary sensors are available: Aerosol Optical Depth (AOD), stratospheric extinction profiles, a qualitative Absorbing Aerosol Index (AAI), fine mode AOD, mineral dust AOD; absorption information and aerosol layer height are in an evaluation phase and the multi-pixel GRASP algorithm for the POLDER instrument is used for selected regions. Validation (vs. AERONET, MAN) and inter-comparison to other satellite datasets (MODIS, MISR, SeaWIFS) proved the high quality of the available datasets comparable to other satellite retrievals and revealed needs for algorithm improvement (for example for higher AOD values) which were taken into account in an iterative evolution cycle. The datasets contain pixel level uncertainty estimates which were also validated and improved in the reprocessing. The use of an ensemble method was tested, where several algorithms are applied to the same sensor. The presentation will summarize and discuss the lessons learned from the 6 years of intensive collaboration and highlight major achievements (significantly improved AOD quality, fine mode AOD, dust AOD, pixel level uncertainties, ensemble approach); also limitations and remaining deficits shall be discussed. An outlook will discuss the way forward for the continuous algorithm improvement and re-processing together with opportunities for time series extension with successor instruments of the Sentinel family and the complementarity of the different satellite aerosol products.

  5. Global radiative effects of solid fuel cookstove aerosol emissions

    Science.gov (United States)

    Huang, Yaoxian; Unger, Nadine; Storelvmo, Trude; Harper, Kandice; Zheng, Yiqi; Heyes, Chris

    2018-04-01

    We apply the NCAR CAM5-Chem global aerosol-climate model to quantify the net global radiative effects of black and organic carbon aerosols from global and Indian solid fuel cookstove emissions for the year 2010. Our assessment accounts for the direct radiative effects, changes to cloud albedo and lifetime (aerosol indirect effect, AIE), impacts on clouds via the vertical temperature profile (semi-direct effect, SDE) and changes in the surface albedo of snow and ice (surface albedo effect). In addition, we provide the first estimate of household solid fuel black carbon emission effects on ice clouds. Anthropogenic emissions are from the IIASA GAINS ECLIPSE V5a inventory. A global dataset of black carbon (BC) and organic aerosol (OA) measurements from surface sites and aerosol optical depth (AOD) from AERONET is used to evaluate the model skill. Compared with observations, the model successfully reproduces the spatial patterns of atmospheric BC and OA concentrations, and agrees with measurements to within a factor of 2. Globally, the simulated AOD agrees well with observations, with a normalized mean bias close to zero. However, the model tends to underestimate AOD over India and China by ˜ 19 ± 4 % but overestimate it over Africa by ˜ 25 ± 11 % (± represents modeled temporal standard deviations for n = 5 run years). Without BC serving as ice nuclei (IN), global and Indian solid fuel cookstove aerosol emissions have net global cooling radiative effects of -141 ± 4 mW m-2 and -12 ± 4 mW m-2, respectively (± represents modeled temporal standard deviations for n = 5 run years). The net radiative impacts are dominated by the AIE and SDE mechanisms, which originate from enhanced cloud condensation nuclei concentrations for the formation of liquid and mixed-phase clouds, and a suppression of convective transport of water vapor from the lower troposphere to the upper troposphere/lower stratosphere that in turn leads to reduced ice cloud formation. When BC is allowed

  6. Ice crystallization in ultrafine water-salt aerosols: nucleation, ice-solution equilibrium, and internal structure.

    Science.gov (United States)

    Hudait, Arpa; Molinero, Valeria

    2014-06-04

    solution. We predict that micrometer-sized particles and nanoparticles have the same equilibrium internal structure. The variation of liquid-vapor surface tension with solute concentration is a key factor in determining whether a solution-embedded ice core or vapor-exposed ice cap is the equilibrium structure of the aerosols. In agreement with experiments, we predict that the structure of mixed-phase HNO3-water particles, representative of polar stratospheric clouds, consists of an ice core surrounded by freeze-concentrated solution. The results of this work are important to determine the phase state and internal structure of sea spray ultrafine aerosols and other mixed-phase particles under atmospherically relevant conditions.

  7. Key aspects of stratospheric tracer modeling using assimilated winds

    Directory of Open Access Journals (Sweden)

    B. Bregman

    2006-01-01

    Full Text Available This study describes key aspects of global chemistry-transport models and their impact on stratospheric tracer transport. We concentrate on global models that use assimilated winds from numerical weather predictions, but the results also apply to tracer transport in general circulation models. We examined grid resolution, numerical diffusion, air parcel dispersion, the wind or mass flux update frequency, and time interpolation. The evaluation is performed with assimilated meteorology from the "operational analyses or operational data" (OD from the European Centre for Medium-Range Weather Forecasts (ECMWF. We also show the effect of the mass flux update frequency using the ECMWF 40-year re-analyses (ERA40. We applied the three-dimensional chemistry-transport Tracer Model version 5 (TM5 and a trajectory model and performed several diagnoses focusing on different transport regimes. Covering different time and spatial scales, we examined (1 polar vortex dynamics during the Arctic winter, (2 the large-scale stratospheric meridional circulation, and (3 air parcel dispersion in the tropical lower stratosphere. Tracer distributions inside the Arctic polar vortex show considerably worse agreement with observations when the model grid resolution in the polar region is reduced to avoid numerical instability. The results are sensitive to the diffusivity of the advection. Nevertheless, the use of a computational cheaper but diffusive advection scheme is feasible for tracer transport when the horizontal grid resolution is equal or smaller than 1 degree. The use of time interpolated winds improves the tracer distributions, particularly in the middle and upper stratosphere. Considerable improvement is found both in the large-scale tracer distribution and in the polar regions when the update frequency of the assimilated winds is increased from 6 to 3 h. It considerably reduces the vertical dispersion of air parcels in the tropical lower stratosphere. Strong

  8. American Association for Aerosol Research (AAAR) `95

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The Fourteenth annual meeting of the American Association for Aerosol Research was held October 9-13, 1995 at Westin William Penn Hotel in Pittsburgh, PA. This volume contains the abstracts of the papers and poster sessions presented at this meeting, grouped by the session in which they were presented as follows: Radiation Effects; Aerosol Deposition; Collision Simulations and Microphysical Behavior; Filtration Theory and Measurements; Materials Synthesis; Radioactive and Nuclear Aerosols; Aerosol Formation, Thermodynamic Properties, and Behavior; Particle Contamination Issues in the Computer Industry; Pharmaceutical Aerosol Technology; Modeling Global/Regional Aerosols; Visibility; Respiratory Deposition; Biomass and Biogenic Aerosols; Aerosol Dynamics; Atmospheric Aerosols.

  9. Interactions of meteoric smoke particles with sulphuric acid in the Earth's stratosphere

    Directory of Open Access Journals (Sweden)

    R. W. Saunders

    2012-05-01

    Full Text Available Nano-sized meteoric smoke particles (MSPs with iron-magnesium silicate compositions, formed in the upper mesosphere as a result of meteoric ablation, may remove sulphuric acid from the gas-phase above 40 km and may also affect the composition and behaviour of supercooled H2SO4-H2O droplets in the global stratospheric aerosol (Junge layer.

    This study describes a time-resolved spectroscopic analysis of the evolution of the ferric (Fe3+ ion originating from amorphous ferrous (Fe2+-based silicate powders dissolved in varying Wt % sulphuric acid (30–75 % solutions over a temperature range of 223–295 K. Complete dissolution of the particles was observed under all conditions. The first-order rate coefficient for dissolution decreases at higher Wt % and lower temperature, which is consistent with the increased solution viscosity limiting diffusion of H2SO4 to the particle surfaces. Dissolution under stratospheric conditions should take less than a week, and is much faster than the dissolution of crystalline Fe2+ compounds.

    The chemistry climate model UMSLIMCAT (based on the UKMO Unified Model was then used to study the transport of MSPs through the middle atmosphere. A series of model experiments were performed with different uptake coefficients. Setting the concentration of 1.5 nm radius MSPs at 80 km to 3000 cm−3 (based on rocket-borne charged particle measurements, the model matches the reported Wt % Fe values of 0.5–1.0 in Junge layer sulphate particles, and the MSP optical extinction between 40 and 75 km measured by a satellite-borne spectrometer, if the global meteoric input rate is about 20 tonnes per day. The model indicates that an uptake coefficient ≥0.01 is required to account for the observed two orders of magnitude depletion of H2SO4 vapour above 40 km.

  10. Aerosol impacts on regional trends in atmospheric stagnation

    Science.gov (United States)

    Mascioli, N. R.; Fiore, A. M.; Previdi, M. J.

    2017-12-01

    Extreme pollution events pose a significant threat to human health and are a leading cause of premature mortality worldwide. While emissions of atmospheric pollutants and their precursors are projected to decrease in the future due to air quality legislation, future climate change may affect the underlying meteorological conditions that contribute to extreme pollution events. Stagnation events, characterized by weak winds and an absence of precipitation, contribute to extreme pollution by halting the removal of pollutants via advection and wet deposition. Here, we use a global climate model (GFDL-CM3) to show that regional stagnation trends over the historical period (1860-2005) are driven by changes in anthropogenic aerosol emissions, rather than rising greenhouse gases. In the northeastern and central United States, aerosol-induced changes in surface and upper level winds have produced significant decreases in the number of stagnant summer days, while decreasing precipitation in the southeast US has increased the number of stagnant summer days. Significant drying over eastern China in response to aerosol forcing contributed to increased stagnation. Additionally, this region was found to be particularly sensitive to changes in local emissions, indicating that improving air quality will also lessen stagnation. In Europe, we find a dipole pattern wherein stagnation decreases over southern Europe and increases over northern Europe in response to global increases in aerosol emissions. We hypothesize that this is due to changes in the large-scale circulation patterns associated with a poleward shift of the North Atlantic storm track. We find that in the future, the combination of declining aerosol emissions and the continued rise of greenhouse gas emissions will lead to a reversal of the historical stagnation trends.

  11. Rigorous determination of stratospheric water vapor trends from MIPAS observations.

    Science.gov (United States)

    Ceccherini, Simone; Carli, Bruno; Raspollini, Piera; Ridolfi, Marco

    2011-05-09

    The trend of stratospheric water vapor as a function of latitude is estimated by the MIPAS measurements by means of a new method that uses the measurement space solution. The method uses all the information provided by the observations avoiding the artifacts introduced by the a priori information and by the interpolation to different vertical grids. The analysis provides very precise values of the trends that, however, are limited by a relatively large systematic error induced by the radiometric calibration error of the instrument. The results show in the five years from 2005 to 2009 a dependence on latitude of the stratospheric (from 37 to 53 km) water vapor trend with a positive value of (0.41 ± 0.16)%yr-1 in the northern hemisphere and less than 0.16%yr-1 in the southern hemisphere.

  12. Hygienic estimation of population doses due to stratospheric fallout

    International Nuclear Information System (INIS)

    Marej, A.N.; Knizhnikov, V.A.

    1980-01-01

    The hygienic estimation of external and internal irradiation of the USSR population due to stratospheric global fallouts of fission products after nuclear explosions and weapon tests, is carried out. Numerical values which characterize the dose-effect dependence in the case of radiation of marrow, bone tissue and whole body are presented. Values of mean individual and population doses of irradiation due to global fallouts within 1963-1975, types of injury and the number of mortal cases due to malignant neoplasms are presented. A conclusion is made that the contribution of radiation due to stratospheric fallouts in the mortality due to malignant neoplasms is insignificant. Annual radiation doses, conditioned by global fallouts within the period of 1963-1975 constitute but several percent from the dose of radiation of the natural radiation background. Results of estimation of genetic consequences of irradiation due to atmospheric fallouts are presented

  13. Eight years of stratospheric ozone observations at Marambio, Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Damski, J; Taalas, P [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research

    1996-12-31

    In this work behaviour of the stratospheric ozone using the total ozone and ozone sounding measurements from Marambio (64 deg 14`S, 56 deg 37`W) at Antarctic Peninsula has been studied. The effects of depleted stratospheric ozone to the UV-B-radiation are investigated employing a radiative transfer model, and the Marambio total ozone measurements. The levels of UV-B radiation have been studied from the point of the erythemal UV-B-doses on the horizontal human epidermis. The low values of total ozone at Marambio are also reflected to the received UV-doses which have increased roughly 20-80% (compared to long term average) during austral spring and summer. In respective to the total amount of ozone, the model calculations show that during October the UV-B-doses can be at the same level they should be during normal summer

  14. Wind tunnel tests of stratospheric airship counter rotating propellers

    Directory of Open Access Journals (Sweden)

    Yaxi Chen

    2015-01-01

    Full Text Available Aerodynamic performance of the high-altitude propeller, especially the counter rotation effects, is experimentally studied. Influences of different configurations on a stratospheric airship, included 2-blade counter-rotating propeller (CRP, dual 2-blade single rotation propellers (SRPs and 4-blade SRP, are also indicated. This research indicates that the effect of counter rotation can greatly improve the efficiency. It shows that the CRP configuration results in a higher efficiency than the dual 2-blade SRPs configuration or 4-blade SRP configuration under the same advance ratio, and the CRP configuration also gains the highest efficiency whether under the situation of providing the same trust or absorbing the same power. It concludes that, for a stratospheric airship, the CRP configuration is better than the multiple SRPs configuration or a multi-blade SRP one.

  15. Solar UV radiation variations and their stratospheric and climatic effects

    Science.gov (United States)

    Donnelly, R. F.; Heath, D. F.

    1985-01-01

    Nimbus-7 SBUV measurements of the short-term solar UV variations caused by solar rotation and active-region evolution have determined the amplitude and wavelength dependence for the active-region component of solar UV variations. Intermediate-term variations lasting several months are associated with rounds of major new active regions. The UV flux stays near the peak value during the current solar cycle variation for more than two years and peaks about two years later than the sunspot number. Nimbus-7 measurements have observed the concurrent stratospheric ozone variations caused by solar UV variations. There is now no doubt that solar UV variations are an important cause of short- and long-term stratospheric variations, but the strength of the coupling to the troposphere and to climate has not yet been proven.

  16. Chemical characterization of local and stratospheric plutonium in Ohio soils

    International Nuclear Information System (INIS)

    Muller, R.N.

    1978-01-01

    The chemical nature of plutonium derived from stratospheric fallout and industrial sources was studied in three agricultural soils. The majority of the soil plutonium was associated with a reductant-soluble, hydrous oxide phase that, under most conditions of terrestrial ecosystems, remains essentially immobile. The proportion of plutonium associated with organic matter (0.1N NaOH-extractable) varied among soils, and increased with decreasing particle size in the same soil. In a soil containing 238 Pu from a local fabrication facility and 239 , 240 Pu from stratospheric fallout, isotopic ratios between the NaOH-extractable and residual phases were essentially constant, indicating that, in these soils, plutonium from both sources behaves similarly. The distribution of soil plutonium with particle size appears to be most directly related to the mass of the soil particle

  17. Eight years of stratospheric ozone observations at Marambio, Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Damski, J.; Taalas, P. [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research

    1995-12-31

    In this work behaviour of the stratospheric ozone using the total ozone and ozone sounding measurements from Marambio (64 deg 14`S, 56 deg 37`W) at Antarctic Peninsula has been studied. The effects of depleted stratospheric ozone to the UV-B-radiation are investigated employing a radiative transfer model, and the Marambio total ozone measurements. The levels of UV-B radiation have been studied from the point of the erythemal UV-B-doses on the horizontal human epidermis. The low values of total ozone at Marambio are also reflected to the received UV-doses which have increased roughly 20-80% (compared to long term average) during austral spring and summer. In respective to the total amount of ozone, the model calculations show that during October the UV-B-doses can be at the same level they should be during normal summer

  18. Aerosol vertical distribution, new particle formation, and jet aircraft particle emissions in the free troposhere and tropopause region; Vertikalverteilung und Neubildungsprozesse des Aerosols und partikelfoermige Flugzeugemissionen in der freien Troposphaere und Tropopausenregion

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, F P

    2000-07-01

    A contribution to the understanding of natural and anthropogenously induced particle formation as well as aerosol physical transformation processes within the free troposphere (FT) is introduced. Documentation and interpretation of empirical data relevant with respect to possible climatologic impact of anthropogenous aerosol emissions into the atmosphere is presented. The first section describes new technique for high spatial resolution measurements of ultrafine aerosol particles by condensation nucleus counters (CNCs), a necessary prerequisite for the observation of natural particle formation and jet aircraft emissions. The second section illustrates vertical distribution and variability ranges of the aerosol in the FT and the tropopause region (TP). Typical microphysical states of the atmospheric aerosol within the Northern Hemisphere are documented by means of systematic measurements during more than 60 flight missions. Simple mathematical parameterizations of the aerosol vertical distribution and aerosol size distributions are developed. Important aerosol sources within the FT are localized and possible aerosol formation processes are discussed. The third section is focussed on jet-engine particle emissions within the FT and TP. A unique inflight experiment for detection of extremely high concentrations (>10{sup 6} cm{sup -3}) of extremely small (donw to <3 nm) aerosols inside the exhaust plumes of several jet aircraft is described. Particle emission indices and emission-controlling parameters are deduced. Most important topic is the impact of fuel sulfur content of kerosine on number, size and chemical composition of jet particle emissions. Generalized results are parameterized in form of lognormal aerosol particle size distributions. (orig.) [German] Ein Beitrag zum Verstaendnis natuerlicher und anthropogen induzierter Aerosolneubildung sowie physikalischer Aerosolumwandlung in der freien Troposphaere wird vorgestellt. Empirisch gewonnenes Datenmaterial wird

  19. Special aerosol sources for certification and test of aerosol radiometers

    International Nuclear Information System (INIS)

    Belkina, S.K.; Zalmanzon, Y.E.; Kuznetsov, Y.V.; Rizin, A.I.; Fertman, D.E.

    1991-01-01

    The results are presented of the development and practical application of new radionuclide source types (Special Aerosol Sources (SAS)), that meet the international standard recommendations, which are used for certification and test of aerosol radiometers (monitors) using model aerosols of plutonium-239, strontium-yttrium-90 or uranium of natural isotope composition and certified against Union of Soviet Socialist Republics USSR national radioactive aerosol standard or by means of a reference radiometer. The original technology for source production allows the particular features of sampling to be taken into account as well as geometry and conditions of radionuclides radiation registration in the sample for the given type of radiometer. (author)

  20. Special aerosol sources for certification and test of aerosol radiometers

    Energy Technology Data Exchange (ETDEWEB)

    Belkina, S.K.; Zalmanzon, Y.E.; Kuznetsov, Y.V.; Rizin, A.I.; Fertman, D.E. (Union Research Institute of Instrumentation, Moscow (USSR))

    1991-01-01

    The results are presented of the development and practical application of new radionuclide source types (Special Aerosol Sources (SAS)), that meet the international standard recommendations, which are used for certification and test of aerosol radiometers (monitors) using model aerosols of plutonium-239, strontium-yttrium-90 or uranium of natural isotope composition and certified against Union of Soviet Socialist Republics USSR national radioactive aerosol standard or by means of a reference radiometer. The original technology for source production allows the particular features of sampling to be taken into account as well as geometry and conditions of radionuclides radiation registration in the sample for the given type of radiometer. (author).

  1. Infrared emission high spectral resolution atlas of the stratospheric limb

    Science.gov (United States)

    Maguire, William C.; Kunde, Virgil G.; Herath, Lawrence W.

    1989-01-01

    An atlas of high resolution infrared emission spectra identifies a number of gaseous atmospheric features significant to stratospheric chemistry in the 770-900/cm and 1100-1360/cm regions at six zenith angles from 86.7 to 95.1 deg. A balloon-borne Michelson interferometer was flown to obtain about 0.03/cm resolution spectra. Two 10/cm extracts are presented here.

  2. A warming tropical central Pacific dries the lower stratosphere

    Science.gov (United States)

    Ding, Qinghua; Fu, Qiang

    2018-04-01

    The amount of water vapor in the tropical lower stratosphere (TLS), which has an important influence on the radiative energy budget of the climate system, is modulated by the temperature variability of the tropical tropopause layer (TTL). The TTL temperature variability is caused by a complex combination of the stratospheric quasi-biennial oscillation (QBO), tropospheric convective processes in the tropics, and the Brewer-Dobson circulation (BDC) driven by mid-latitude and subtropical atmospheric waves. In 2000, the TLS water vapor amount exhibited a stepwise transition to a dry phase, apparently caused by a change in the BDC. In this study, we present observational and modeling evidence that the epochal change of water vapor between the periods of 1992-2000 and 2001-2005 was also partly caused by a concurrent sea surface temperature (SST) warming in the tropical central Pacific. This SST warming cools the TTL above by enhancing the equatorial wave-induced upward motion near the tropopause, which consequently reduces the amount of water vapor entering the stratosphere. The QBO affects the TLS water vapor primarily on inter-annual timescales, whereas a classical El Niño southern oscillation (ENSO) event has small effect on tropical mean TLS water vapor because its responses are longitudinally out of phase. This study suggests that the tropical central Pacific SST is another driver of TLS water vapor variability on inter-decadal timescales and the tropical SST changes could contribute to about 30% of the step-wise drop of the lower stratospheric water vapor from 1992-2000 to 2001-2005.

  3. Dust ablation on the giant planets: Consequences for stratospheric photochemistry

    Science.gov (United States)

    Moses, Julianne I.; Poppe, Andrew R.

    2017-11-01

    Ablation of interplanetary dust supplies oxygen to the upper atmospheres of Jupiter, Saturn, Uranus, and Neptune. Using recent dynamical model predictions for the dust influx rates to the giant planets (Poppe et al., 2016), we calculate the ablation profiles and investigate the subsequent coupled oxygen-hydrocarbon neutral photochemistry in the stratospheres of these planets. We find that dust grains from the Edgeworth-Kuiper Belt, Jupiter-family comets, and Oort-cloud comets supply an effective oxygen influx rate of 1.0-0.7+2.2 ×107 O atoms cm-2 s-1 to Jupiter, 7.4-5.1+16 ×104 cm-2 s-1 to Saturn, 8.9-6.1+19 ×104 cm-2 s-1 to Uranus, and 7.5-5.1+16 ×105 cm-2 s-1 to Neptune. The fate of the ablated oxygen depends in part on the molecular/atomic form of the initially delivered products, and on the altitude at which it was deposited. The dominant stratospheric products are CO, H2O, and CO2, which are relatively stable photochemically. Model-data comparisons suggest that interplanetary dust grains deliver an important component of the external oxygen to Jupiter and Uranus but fall far short of the amount needed to explain the CO abundance currently seen in the middle stratospheres of Saturn and Neptune. Our results are consistent with the theory that all of the giant planets have experienced large cometary impacts within the last few hundred years. Our results also suggest that the low background H2O abundance in Jupiter's stratosphere is indicative of effective conversion of meteoric oxygen to CO during or immediately after the ablation process - photochemistry alone cannot efficiently convert the H2O into CO on the giant planets.

  4. Alert with destruction of stratospheric ozone: 95 Nobel Prize Winners

    International Nuclear Information System (INIS)

    Santamaria, J.; Zurita, E.

    1995-01-01

    After briefly summarizing the discoveries of the 95 Nobel Prize Winners in Chemistry related to the threats to the ozone layer by chemical pollutants, we make a soft presentation of the overall problem of stratospheric ozone, starting with the destructive catalytic cycles of the pollutant-based free radicals, following with the diffusion mathematical models in Atmospheric Chemistry, and ending with the increasing annual drama of the ozone hole in the Antarctica. (Author)

  5. A vortex dynamics perspective on stratospheric sudden warmings

    OpenAIRE

    Matthewman, N. J.

    2009-01-01

    A vortex dynamics approach is used to study the underlying mechanisms leading to polar vortex breakdown during stratospheric sudden warmings (SSWs). Observational data are used in chapter 2 to construct climatologies of the Arctic polar vortex structure during vortex-splitting and vortex-displacement SSWs occurring between 1958 and 2002. During vortex-splitting SSWs, polar vortex breakdown is shown to be typically independent of height (barotropic), whereas breakdown during vor...

  6. Future emission scenarios for chemicals that may deplete stratospheric ozone

    International Nuclear Information System (INIS)

    Hammitt, J.K; Camm, Frank; Mooz, W.E.; Wolf, K.A.; Bamezai, Anil; Connel, P.S.; Wuebbles, D.J.

    1990-01-01

    Scenarios are developed for long-term future emissions of seven of the most important manmade chemicals that may deplete ozone and the corresponding effect on stratospheric ozone concentrations is calculated using a one-dimensional atmospheric model. The scenarios are based on detailed analysis of the markets for products that use these chemicals and span a central 90% probability interval for the chemicals joint effect on calculated ozone abundance, assuming no additional regulations. (author). 22 refs., 2 figs., 5 tabs

  7. A new formulation of equivalent effective stratospheric chlorine (EESC

    Directory of Open Access Journals (Sweden)

    P. A. Newman

    2007-09-01

    Full Text Available Equivalent effective stratospheric chlorine (EESC is a convenient parameter to quantify the effects of halogens (chlorine and bromine on ozone depletion in the stratosphere. We show, discuss, and analyze a new formulation of EESC that now includes the effects of age-of-air dependent fractional release values and an age-of-air spectrum. This EESC can be more appropriately applied to various parts of the stratosphere because of this dependence on mean age-of-air. This new formulation provides quantitative estimates of EESC that can be directly related to inorganic chlorine and bromine throughout the stratosphere. In this paper, we first provide a detailed description of the EESC calculation. We then use this EESC formulation to estimate that human-produced ozone depleting substances will recover to 1980 levels in 2041 in the midlatitudes, and 2067 over Antarctica. These recovery dates are based upon the assumption that the international agreements for regulating ozone-depleting substances are adhered to. In addition to recovery dates, we also estimate the uncertainties and possible problems in the estimated times of recovery. The midlatitude recovery of 2041 has a 95% confidence uncertainty from 2028 to 2049, while the 2067 Antarctic recovery has a 95% confidence uncertainty from 2056 to 2078. The principal uncertainties are from the estimated mean age-of-air and fractional release values, and the assumption that these quantities are time independent. Using other model estimates of age decrease due to climate change, we estimate that midlatitude recovery may be significantly accelerated.

  8. Long duration balloon flights in the middle stratosphere

    Science.gov (United States)

    Malaterre, P.

    1993-02-01

    Research and development performed by the French Space Agency (CNES) over the past 10 years has given the scientific community the Infrared Montgolfiere, a balloon capable of lifting 50-kg payloads into the stratosphere for periods of several weeks. The Infrared Montgolfiere is a hot air balloon that captures infrared radiation using the earth as a heat source. Thirty flights have been launched so far, some lasting more than sixty days and circling the globe twice.

  9. Location and data collection for long stratospheric balloon flights

    Science.gov (United States)

    Malaterre, P.

    Stratospheric balloons capable of taking a 30 kg scientific payload to an altitude of 22 to 30 km for 1 month or more were developed. In-flight experiments were used to qualify the designs of a pumpkin shaped superpressure balloon and an infrared hot air balloon. Tracking of the flights (location and transmission of the parameters measured on board) was achieved using a telemetry gondola including an ARGOS beacon adapted for operation in the low temperatures encountered.

  10. Mexico City aerosol study

    International Nuclear Information System (INIS)

    Falcon, Y.I.; Ramirez, C.R.

    1987-01-01

    A major task in the field of air pollution monitoring is the development of devices for determining the mass and composition of airborne particulate matter as a function of size - and time. The sample collection device must be designed giving consideration to the nature of the aerosol and to the effects of the aerosol on human health. It has been established that particles smaller than 3.5 μm in diameter can penetrate deeply into the human respiratory system, and that larger particles are trapped in the upper respiratory passages. For these reasons, it is desirable to use a dichotomous sampler to collect particles in two size ranges, rather than to collect total particulates on a single filter. The authors discuss a study in Mexico City using a dichotomous sampler

  11. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    emissions produced directly from bubble bursting as the result of air entrainment from breaking waves and particles generated from secondary emissions of volatile organic compounds. In the first paper, we study the chemical properties of particles produced from several sea water proxies with the use...... of a cloud condensation nuclei ounter. Proxy solutions with high inorganic salt concentrations and some organics produce sea spray aerosol particles with little change in cloud condensation activity relative to pure salts. Comparison is made between a frit based method for bubble production and a plunging...... a relationship between plunging jet particle ux, oceanic particle u