WorldWideScience

Sample records for stratospheric aerosol climatology

  1. 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

  2. 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.

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  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 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.

  11. 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

  12. 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

  13. 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.

  14. 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).

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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...

  2. Climatology of the northern hemisphere stratosphere derived from Berlin analyses. Pt. 1. Monthly means

    Energy Technology Data Exchange (ETDEWEB)

    Pawson, S; Labitzke, K; Lenschow, R; Naujokat, B; Rajewski, B; Wiesner, M; Wohlfart, R C

    1933-01-01

    This work presents a climatology of the northern hemisphere lower and middle stratosphere derived from daily radiosonde observations subjectively analysed in the Stratospheric Research Group of the 'Meteorologisches Institut der Freien Universitaet Berlin'. Previous climatologies from these data were presented by Labitzke (1972), van Loon et al. (1972), and by Labitzke and Goretzki (1982). Although some more recent climatological fields have been presented in several works by members of the group, no complete atlas has been compiled for some time. The work is intended to serve as a reference for people interested in the stratosphere and, particularly, the climate analysis and modelling communities, which require contemporary analyses of the available data in order to interpret their products. In this first part of the climatological atlas, monthly mean data are presented. (orig./KW)

  3. Climatology of the northern hemisphere stratosphere derived from Berlin analyses. Pt. 1. Monthly means

    International Nuclear Information System (INIS)

    Pawson, S.; Labitzke, K.; Lenschow, R.; Naujokat, B.; Rajewski, B.; Wiesner, M.; Wohlfart, R.C.

    1993-01-01

    This work presents a climatology of the northern hemisphere lower and middle stratosphere derived from daily radiosonde observations subjectively analysed in the Stratospheric Research Group of the 'Meteorologisches Institut der Freien Universitaet Berlin'. Previous climatologies from these data were presented by Labitzke (1972), van Loon et al. (1972), and by Labitzke and Goretzki (1982). Although some more recent climatological fields have been presented in several works by members of the group, no complete atlas has been compiled for some time. The work is intended to serve as a reference for people interested in the stratosphere and, particularly, the climate analysis and modelling communities, which require contemporary analyses of the available data in order to interpret their products. In this first part of the climatological atlas, monthly mean data are presented. (orig./KW)

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. Climatology of Aerosol Optical Properties in Southern Africa

    Science.gov (United States)

    Queface, Antonio J.; Piketh, Stuart J.; Eck, Thomas F.; Tsay, Si-Chee

    2011-01-01

    A thorough regionally dependent understanding of optical properties of aerosols and their spatial and temporal distribution is required before we can accurately evaluate aerosol effects in the climate system. Long term measurements of aerosol optical depth, Angstrom exponent and retrieved single scattering albedo and size distribution, were analyzed and compiled into an aerosol optical properties climatology for southern Africa. Monitoring of aerosol parameters have been made by the AERONET program since the middle of the last decade in southern Africa. This valuable information provided an opportunity for understanding how aerosols of different types influence the regional radiation budget. Two long term sites, Mongu in Zambia and Skukuza in South Africa formed the core sources of data in this study. Results show that seasonal variation of aerosol optical thicknesses at 500 nm in southern Africa are characterized by low seasonal multi-month mean values (0.11 to 0.17) from December to May, medium values (0.20 to 0.27) between June and August, and high to very high values (0.30 to 0.46) during September to November. The spatial distribution of aerosol loadings shows that the north has high magnitudes than the south in the biomass burning season and the opposite in none biomass burning season. From the present aerosol data, no long term discernable trends are observable in aerosol concentrations in this region. This study also reveals that biomass burning aerosols contribute the bulk of the aerosol loading in August-October. Therefore if biomass burning could be controlled, southern Africa will experience a significant reduction in total atmospheric aerosol loading. In addition to that, aerosol volume size distribution is characterized by low concentrations in the non biomass burning period and well balanced particle size contributions of both coarse and fine modes. In contrast high concentrations are characteristic of biomass burning period, combined with

  9. 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.

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

    Science.gov (United States)

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

    2011-01-01

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

  11. Steps Toward an EOS-Era Aerosol Type Climatology

    Science.gov (United States)

    Kahn, Ralph A.

    2012-01-01

    We still have a way to go to develop a global climatology of aerosol type from the EOS-era satellite data record that currently spans more than 12 years of observations. We have demonstrated the ability to retrieve aerosol type regionally, providing a classification based on the combined constraints on particle size, shape, and single-scattering albedo (SSA) from the MISR instrument. Under good but not necessarily ideal conditions, the MISR data can distinguish three-to-five size bins, two-to-four bins in SSA, and spherical vs. non-spherical particles. However, retrieval sensitivity varies enormously with scene conditions. So, for example, there is less information about aerosol type when the mid-visible aerosol optical depth (AOD) is less that about 0.15 or 0.2, or when the range of scattering angles observed is reduced by solar geometry, even though the quality of the AOD retrieval itself is much less sensitive to these factors. This presentation will review a series of studies aimed at assessing the capabilities, as well as the limitations, of MISR aerosol type retrievals involving wildfire smoke, desert dust, volcanic ash, and urban pollution, in specific cases where suborbital validation data are available. A synthesis of results, planned upgrades to the MISR Standard aerosol algorithm to improve aerosol type retrievals, and steps toward the development of an aerosol type quality flag for the Standard product, will also be covered.

  12. 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.

  13. 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.

  14. 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

  15. A stratospheric NO2 climatology from Odin/OSIRIS limb-scatter measurements

    International Nuclear Information System (INIS)

    Brohede, S.; Murtagh, D.; Berthet, G.; Haley, C.S.

    2007-01-01

    Since the late 1960s, it has been known that stratospheric nitrogen dioxide (NO 2 ) and ozone are closely coupled. However, stratospheric nitrogen chemistry is not yet fully understood, given the lack of observing systems that can provide both high vertical and temporal resolution measurements of NO 2 . Limb-scattering data from the optical spectrograph and infrared imager system (OSIRIS) aboard the Odin satellite was used in this study along with a photochemical box model to investigate stratospheric NO 2 climatology in terms of mean and standard deviation as a function of latitude, altitude, month and local solar time. The Odin orbit provided near global coverage around the equinoxes and hemispheric coverage elsewhere, due to lack of sunlight. The mean NO 2 field at a specific local solar time involved high concentrations in the polar summer, peaking at about 25 km, with a negative equatorward gradient. High levels between 40 to 50 degrees latitude at 30 km in the winter/spring hemisphere were also found, and were associated with the Noxon-cliff. The diurnal cycle revealed the lowest NO 2 concentrations just after sunrise and steep gradients at twilight. The 1σ standard deviation was around 20 per cent, except for winter and spring high latitudes, where values were above 50 per cent and stretched through the entire stratosphere. NO 2 concentrations were found to be log-normally distributed. Comparisons with the REPROBUS chemical transport model for climatology showed that the relative differences for the mean values were below 20 per cent and comparable to the estimated OSIRIS systematic uncertainty. The polar regions in winter/spring throughout the atmosphere and equatorial regions below 25 km were exceptions, where OSIRIS was higher by 40 per cent and more. It was concluded that further study is needed to determine if these discrepancies are due to limitations of the model. 47 refs., 10 figs., 1 appendix

  16. 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.

  17. A climatology of polar stratospheric cloud composition between 2002 and 2012 based on MIPAS/Envisat observations

    Science.gov (United States)

    Spang, Reinhold; Hoffmann, Lars; Müller, Rolf; Grooß, Jens-Uwe; Tritscher, Ines; Höpfner, Michael; Pitts, Michael; Orr, Andrew; Riese, Martin

    2018-04-01

    The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument aboard the European Space Agency (ESA) Envisat satellite operated from July 2002 to April 2012. The infrared limb emission measurements provide a unique dataset of day and night observations of polar stratospheric clouds (PSCs) up to both poles. A recent classification method for PSC types in infrared (IR) limb spectra using spectral measurements in different atmospheric window regions has been applied to the complete mission period of MIPAS. The method uses a simple probabilistic classifier based on Bayes' theorem with a strong independence assumption on a combination of a well-established two-colour ratio method and multiple 2-D probability density functions of brightness temperature differences. The Bayesian classifier distinguishes between solid particles of ice, nitric acid trihydrate (NAT), and liquid droplets of supercooled ternary solution (STS), as well as mixed types. A climatology of MIPAS PSC occurrence and specific PSC classes has been compiled. Comparisons with results from the classification scheme of the spaceborne lidar Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on the Cloud-Aerosol-Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite show excellent correspondence in the spatial and temporal evolution for the area of PSC coverage (APSC) even for each PSC class. Probability density functions of the PSC temperature, retrieved for each class with respect to equilibrium temperature of ice and based on coincident temperatures from meteorological reanalyses, are in accordance with the microphysical knowledge of the formation processes with respect to temperature for all three PSC types.This paper represents unprecedented pole-covering day- and nighttime climatology of the PSC distributions and their composition of different particle types. The dataset allows analyses on the temporal and spatial development of the PSC formation process over

  18. A climatology of polar stratospheric cloud composition between 2002 and 2012 based on MIPAS/Envisat observations

    Directory of Open Access Journals (Sweden)

    R. Spang

    2018-04-01

    Full Text Available The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS instrument aboard the European Space Agency (ESA Envisat satellite operated from July 2002 to April 2012. The infrared limb emission measurements provide a unique dataset of day and night observations of polar stratospheric clouds (PSCs up to both poles. A recent classification method for PSC types in infrared (IR limb spectra using spectral measurements in different atmospheric window regions has been applied to the complete mission period of MIPAS. The method uses a simple probabilistic classifier based on Bayes' theorem with a strong independence assumption on a combination of a well-established two-colour ratio method and multiple 2-D probability density functions of brightness temperature differences. The Bayesian classifier distinguishes between solid particles of ice, nitric acid trihydrate (NAT, and liquid droplets of supercooled ternary solution (STS, as well as mixed types. A climatology of MIPAS PSC occurrence and specific PSC classes has been compiled. Comparisons with results from the classification scheme of the spaceborne lidar Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP on the Cloud-Aerosol-Lidar and Infrared Pathfinder Satellite Observations (CALIPSO satellite show excellent correspondence in the spatial and temporal evolution for the area of PSC coverage (APSC even for each PSC class. Probability density functions of the PSC temperature, retrieved for each class with respect to equilibrium temperature of ice and based on coincident temperatures from meteorological reanalyses, are in accordance with the microphysical knowledge of the formation processes with respect to temperature for all three PSC types.This paper represents unprecedented pole-covering day- and nighttime climatology of the PSC distributions and their composition of different particle types. The dataset allows analyses on the temporal and spatial development of the PSC formation

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. A Climatology of Global Aerosol Mixtures to Support Sentinel-5P and Earthcare Mission Applications

    Science.gov (United States)

    Taylor, M.; Kazadzis, S.; Amaridis, V.; Kahn, R. A.

    2015-11-01

    Since constraining aerosol type with satellite remote sensing continues to be a challenge, we present a newly derived global climatology of aerosol mixtures to support atmospheric composition studies that are planned for Sentinel-5P and EarthCARE.The global climatology is obtained via application of iterative cluster analysis to gridded global decadal and seasonal mean values of the aerosol optical depth (AOD) of sulfate, biomass burning, mineral dust and marine aerosol as a proportion of the total AOD at 500nm output from the Goddard Chemistry Aerosol Radiation and Transport (GOCART). For both the decadal and seasonal means, the number of aerosol mixtures (clusters) identified is ≈10. Analysis of the percentage contribution of the component aerosol types to each mixture allowed development of a straightforward naming convention and taxonomy, and assignment of primary colours for the generation of true colour-mixing and easy-to-interpret maps of the spatial distribution of clusters across the global grid. To further help characterize the mixtures, aerosol robotic network (AERONET) Level 2.0 Version 2 inversion products were extracted from each cluster‟s spatial domain and used to estimate climatological values of key optical and microphysical parameters.The aerosol type climatology represents current knowledge that would be enhanced, possibly corrected, and refined by high temporal and spectral resolution, cloud-free observations produced by Sentinel-5P and EarthCARE instruments. The global decadal mean and seasonal gridded partitions comprise a preliminary reference framework and global climatology that can help inform the choice of components and mixtures in aerosol retrieval algorithms used by instruments such as TROPOMI and ATLID, and to test retrieval results.

  5. 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.

  6. 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.

  7. 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

  8. Development and Testing of the New Surface LER Climatology for OMI UV Aerosol Retrievals

    Science.gov (United States)

    Gupta, Pawan; Torres, Omar; Jethva, Hiren; Ahn, Changwoo

    2014-01-01

    Ozone Monitoring Instrument (OMI) onboard Aura satellite retrieved aerosols properties using UV part of solar spectrum. The OMI near UV aerosol algorithm (OMAERUV) is a global inversion scheme which retrieves aerosol properties both over ocean and land. The current version of the algorithm makes use of TOMS derived Lambertian Equivalent Reflectance (LER) climatology. A new monthly climatology of surface LER at 354 and 388 nm have been developed. This will replace TOMS LER (380 nm and 354nm) climatology in OMI near UV aerosol retrieval algorithm. The main objectives of this study is to produce high resolution (quarter degree) surface LER sets as compared to existing one degree TOMS surface LERs, to product instrument and wavelength consistent surface climatology. Nine years of OMI observations have been used to derive monthly climatology of surface LER. MODIS derived aerosol optical depth (AOD) have been used to make aerosol corrections on OMI wavelengths. MODIS derived BRDF adjusted reflectance product has been also used to capture seasonal changes in the surface characteristics. Finally spatial and temporal averaging techniques have been used to fill the gaps around the globes, especially in the regions with consistent cloud cover such as Amazon. After implementation of new surface data in the research version of algorithm, comparisons of AOD and single scattering albedo (SSA) have been performed over global AERONET sites for year 2007. Preliminary results shows improvements in AOD retrievals globally but more significance improvement were observed over desert and bright locations. We will present methodology of deriving surface data sets and will discuss the observed changes in retrieved aerosol properties with respect to reference AERONET measurements.

  9. A Climatology of Polar Stratospheric Cloud Types by MIPAS-Envisat

    Science.gov (United States)

    Spang, Reinhold; Hoffmann, Lars; Griessbach, Sabine; Orr, Andrew; Höpfner, Michael; Müller, Rolf

    2015-04-01

    For Chemistry Climate Models (CCM) it is still a challenging task to properly represent the evolution of the polar vortices over the entire winter season. The models usually do not include comprehensive microphysical modules to evolve the formation of different types of polar stratospheric clouds (PSC) over the winter. Consequently, predictions on the development and recovery of the future ozone hole have relatively large uncertainties. A climatological record of hemispheric measurement of PSC types could help to better validate and improve the PSC schemes in CCMs. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument onboard the ESA Envisat satellite operated from July 2002 to April 2012. The infra-red limb emission measurements compile a unique dataset of day and night measurements of polar stratospheric clouds up to the poles. From the spectral measurements in the 4.15-14.6 microns range it is possible to select a number of atmospheric window regions and spectral signatures to classify PSC cloud types like nitric acid hydrates, sulfuric ternary solution droplets, and ice particles. The cloud detection sensitivity is similar to space borne lidars, but MIPAS adds complementary information due to its different measurement technique (limb instead of nadir) and wavelength region. Here we will describe a new classification method for PSCs based on the combination of multiple brightness temperature differences (BTD) and colour ratios. Probability density functions (PDF) of the MIPAS measurements in conjunction with a database of radiative transfer model calculations of realistic PSC particle size distributions enable the definition of regions attributed to specific or mixed types clouds. Applying a naive bias classifier for independent criteria to all defined classes in four 2D PDF distributions, it is possible to assign the most likely PSC type to any measured cloud spectrum. Statistical Monte Carlo test have been applied to quantify

  10. Climatology

    International Nuclear Information System (INIS)

    Schoenwiese, C.D.

    1994-01-01

    Climatology is an important field of continuing interest in nearly all fields of science and beyond. In view of this interdisciplinary role, the textbook gives an accurate and intelligible introduction to the fundamentals and modern aspects of general climatology. It covers the basic concepts of climate elements, the physical processes, atmospheric circulation and further components of the ''climate system'' (ocean, ice, continents), as well as an explanation of the observed field characteristics of the climate, problems of climate modelling fundamentals of bioclimatology, and, last but not least, key aspects of climate history and anthropogenic effects on climate. (orig.) [de

  11. Aerosol climatology using a tunable spectral variability cloud screening of AERONET data

    Science.gov (United States)

    Kaufman, Yoram J.; Gobbi, Gian Paolo; Koren, Ilan

    2005-01-01

    Can cloud screening of an aerosol data set, affect the aerosol optical thickness (AOT) climatology? Aerosols, humidity and clouds are correlated. Therefore, rigorous cloud screening can systematically bias towards less cloudy conditions, underestimating the average AOT. Here, using AERONET data we show that systematic rejection of variable atmospheric optical conditions can generate such bias in the average AOT. Therefore we recommend (1) to introduce more powerful spectral variability cloud screening and (2) to change the philosophy behind present aerosol climatologies: Instead of systematically rejecting all cloud contaminations, we suggest to intentionally allow the presence of cloud contamination, estimate the statistical impact of the contamination and correct for it. The analysis, applied to 10 AERONET stations with approx. 4 years of data, shows almost no change for Rome (Italy), but up to a change in AOT of 0.12 in Beijing (PRC). Similar technique may be explored for satellite analysis, e.g. MODIS.

  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. climatology of air mass trajectories and aerosol optical thickness ...

    African Journals Online (AJOL)

    George

    We present in this paper a climatological study of back trajectories of air masses ... obtained by inversion of photometric measurements of AERONET network. ... the arid Sahel region adjacent in the north to the Sahara ... the city a strategic position in the study of the .... atmospheric emergencies, diagnostic case studies and.

  14. 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.

  15. Climatological aspects of aerosol optical properties in Northern Greece

    Directory of Open Access Journals (Sweden)

    E. Gerasopoulos

    2003-01-01

    Full Text Available Measurements of aerosol optical properties (aerosol optical depth, scattering and backscattering coefficients have been conducted at two ground-based sites in Northern Greece, Ouranoupolis (40° 23' N, 23° 57' E, 170 m a.s.l. and Thessaloniki (40° 38' N, 22° 57' E, 80 m a.s.l., between 1999 and 2002. The frequency distributions of the observed parameters have revealed the presence of individual modes of high and low values, indicating the influence from different sources. At both sites, the mean aerosol optical depth at 500 nm was 0.23. Values increase considerably during summer when they remain persistently between 0.3 and 0.5, going up to 0.7-0.8 during specific cases. The mean value of 65±40 Mm-1 of the particle scattering coefficient at 550 nm reflects the impact of continental pollution in the regional boundary layer. Trajectory analysis has shown that higher values of aerosol optical depth and the scattering coefficient are found in the east sector (former Soviet Union countries, eastern Balkan countries, whereas cleaner conditions are found for the NW direction. The influence of Sahara dust events is clearly reflected in the Ångström exponents. About 45-60% of the observed diurnal variation of the optical properties was attributed to the growth of aerosols with humidity, while the rest of the variability is in phase with the evolution of the sea-breeze cell. The contribution of local pollution is estimated to contribute 35±10% to the average aerosol optical depth at the Thessaloniki site during summer. Finally, the aerosol scale height (aerosol optical depth divided by scattering coefficient was found to be related to the height of the boundary layer with values between 0.5-1 km during winter and up to 2.5-3 km during summer.

  16. Hemispheric transport and influence of meteorology on global aerosol climatology

    Directory of Open Access Journals (Sweden)

    T. L. Zhao

    2012-08-01

    Full Text Available Based on a 10-yr simulation with the global air quality modeling system GEM-AQ/EC, the northern hemispheric aerosol transport with the inter-annual and seasonal variability as well as the mean climate was investigated. The intercontinental aerosol transport is predominant in the zonal direction from west to east with the ranges of inter-annual variability between 14% and 63%, and is 0.5–2 orders of magnitude weaker in the meridional direction but with larger inter-annual variability. The aerosol transport is found to fluctuate seasonally with a factor of 5–8 between the maximum in late winter and spring and the minimum in late summer and fall. Three meteorological factors controlling the intercontinental aerosol transport and its inter-annual variations are identified from the modeling results: (1 Anomalies in the mid-latitude westerlies in the troposphere. (2 Variations of precipitation over the intercontinental transport pathways and (3 Changes of meteorological conditions within the boundary layer. Changed only by the meteorology, the aerosol column loadings in the free troposphere over the source regions of Europe, North America, South and East Asia vary inter-annually with the highest magnitudes of 30–37% in January and December and the lowest magnitudes of 16–20% in August and September, and the inter-annual aerosol variability within the boundary layer influencing the surface concentrations with the magnitudes from 6% to 20% is more region-dependent. As the strongest climatic signal, the El Niño-Southern Oscillation (ENSO can lead the anomalies in the intercontinental aerosols in El Niño- and La Niña-years respectively with the strong and weak transport of the mid-latitude westerlies and the low latitude easterlies in the Northern Hemisphere (NH.

  17. 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

  18. Progress Toward a Global, EOS-Era Aerosol Air Mass Type Climatology

    Science.gov (United States)

    Kahn, Ralph A.

    2012-01-01

    The MISR and MODIS instruments aboard the NASA Earth Observing System's Terra Satellite have been collecting data containing information about the state of Earth's atmosphere and surface for over eleven years. Data from these instruments have been used to develop a global, monthly climatology of aerosol amount that is widely used as a constraint on climate models, including those used for the 2007 IPCC assessment report. The next frontier in assessing aerosol radiative forcing of climate is aerosol type, and in particular, the absorption properties of major aerosol air masses. This presentation will focus on the prospects for constraining aerosol type globally, and the steps we are taking to apply a combination of satellite and suborbital data to this challenge.

  19. 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.

  20. Evaluation of spatio-temporal variability of Hamburg Aerosol Climatology against aerosol datasets from MODIS and CALIOP

    Directory of Open Access Journals (Sweden)

    V. Pappas

    2013-08-01

    Full Text Available The new global aerosol climatology named HAC (Hamburg Aerosol Climatology is compared against MODIS (Collection 5, 2000–2007 and CALIOP (Level 2-version 3, 2006–2011 retrievals. The comparison of aerosol optical depth (AOD from HAC against MODIS shows larger HAC AOD values over regions with higher aerosol loads and smaller HAC AOD values than MODIS for regions with lower loads. The HAC data are found to be more reliable over land and for low AOD values. The largest differences between HAC and MODIS occur from March to August for the Northern Hemisphere and from September to February for the Southern Hemisphere. In addition, both the spectral variability and vertical distribution of the HAC AOD are examined at selected AERONET (1998–2007 sites, representative of main aerosol types (pollutants, sea salt, biomass and dust. Based on comparisons against spectral AOD values from AERONET, the mean absolute percentage error in HAC AOD data is 25% at ultraviolet wavelengths (400 nm, 6–12% at visible and 18% at near-infrared (1000 nm. For the same AERONET sites, the HAC AOD vertical distribution is compared against CALIOP space lidar data. On a daily average basis, HAD AOD is less by 9% in the lowest 3 km than CALIOP values, especially for sites with biomass burning smoke, desert dust and sea salt spray. Above the boundary layer, the HAC AOD vertical distribution is reliable.

  1. A 20-year simulated climatology of global dust aerosol deposition.

    Science.gov (United States)

    Zheng, Yu; Zhao, Tianliang; Che, Huizheng; Liu, Yu; Han, Yongxiang; Liu, Chong; Xiong, Jie; Liu, Jianhui; Zhou, Yike

    2016-07-01

    Based on a 20-year (1991-2010) simulation of dust aerosol deposition with the global climate model CAM5.1 (Community Atmosphere Model, version 5.1), the spatial and temporal variations of dust aerosol deposition were analyzed using climate statistical methods. The results indicated that the annual amount of global dust aerosol deposition was approximately 1161±31Mt, with a decreasing trend, and its interannual variation range of 2.70% over 1991-2010. The 20-year average ratio of global dust dry to wet depositions was 1.12, with interannual variation of 2.24%, showing the quantity of dry deposition of dust aerosol was greater than dust wet deposition. High dry deposition was centered over continental deserts and surrounding regions, while wet deposition was a dominant deposition process over the North Atlantic, North Pacific and northern Indian Ocean. Furthermore, both dry and wet deposition presented a zonal distribution. To examine the regional changes of dust aerosol deposition on land and sea areas, we chose the North Atlantic, Eurasia, northern Indian Ocean, North Pacific and Australia to analyze the interannual and seasonal variations of dust deposition and dry-to-wet deposition ratio. The deposition amounts of each region showed interannual fluctuations with the largest variation range at around 26.96% in the northern Indian Ocean area, followed by the North Pacific (16.47%), Australia (9.76%), North Atlantic (9.43%) and Eurasia (6.03%). The northern Indian Ocean also had the greatest amplitude of interannual variation in dry-to-wet deposition ratio, at 22.41%, followed by the North Atlantic (9.69%), Australia (6.82%), North Pacific (6.31%) and Eurasia (4.36%). Dust aerosol presented a seasonal cycle, with typically strong deposition in spring and summer and weak deposition in autumn and winter. The dust deposition over the northern Indian Ocean exhibited the greatest seasonal change range at about 118.00%, while the North Atlantic showed the lowest seasonal

  2. An Aircraft-Based Upper Troposphere Lower Stratosphere O3, CO, and H2O Climatology for the Northern Hemisphere

    Science.gov (United States)

    Tilmes, S.; Pan, L. L.; Hoor, P.; Atlas, E.; Avery, M. A.; Campos, T.; Christensen, L. E.; Diskin, G. S.; Gao, R.-S.; Herman, R. L.; hide

    2010-01-01

    We present a climatology of O3, CO, and H2O for the upper troposphere and lower stratosphere (UTLS), based on a large collection of high ]resolution research aircraft data taken between 1995 and 2008. To group aircraft observations with sparse horizontal coverage, the UTLS is divided into three regimes: the tropics, subtropics, and the polar region. These regimes are defined using a set of simple criteria based on tropopause height and multiple tropopause conditions. Tropopause ]referenced tracer profiles and tracer ]tracer correlations show distinct characteristics for each regime, which reflect the underlying transport processes. The UTLS climatology derived here shows many features of earlier climatologies. In addition, mixed air masses in the subtropics, identified by O3 ]CO correlations, show two characteristic modes in the tracer ]tracer space that are a result of mixed air masses in layers above and below the tropopause (TP). A thin layer of mixed air (1.2 km around the tropopause) is identified for all regions and seasons, where tracer gradients across the TP are largest. The most pronounced influence of mixing between the tropical transition layer and the subtropics was found in spring and summer in the region above 380 K potential temperature. The vertical extent of mixed air masses between UT and LS reaches up to 5 km above the TP. The tracer correlations and distributions in the UTLS derived here can serve as a reference for model and satellite data evaluation

  3. 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.

  4. Steps Toward an EOS-Era Aerosol Air Mass Type Climatology

    Science.gov (United States)

    Kahn, Ralph A.

    2012-01-01

    We still have a way to go to develop a global climatology of aerosol type from the EOS-era satellite data record that currently spans more than 12 years of observations. We have demonstrated the ability to retrieve aerosol type regionally, providing a classification based on the combined constraints on particle size, shape, and single-scattering albedo (SSA) from the MISR instrument. Under good but not necessarily ideal conditions, the MISR data can distinguish three-to-five size bins, two-to-four bins in SSA, and spherical vs. non-spherical particles. However, retrieval sensitivity varies enormously with scene conditions. So, for example, there is less information about aerosol type when the mid-visible aerosol optical depth (AOD) is less that about 0.15 or 0.2.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. Long-term aerosol climatology over Indo-Gangetic Plain: Trend, prediction and potential source fields

    Science.gov (United States)

    Kumar, M.; Parmar, K. S.; Kumar, D. B.; Mhawish, A.; Broday, D. M.; Mall, R. K.; Banerjee, T.

    2018-05-01

    Long-term aerosol climatology is derived using Terra MODIS (Collection 6) enhanced Deep Blue (DB) AOD retrieval algorithm to investigate decadal trend (2006-2015) in columnar aerosol loading, future scenarios and potential source fields over the Indo-Gangetic Plain (IGP), South Asia. Satellite based aerosol climatology was analyzed in two contexts: for the entire IGP considering area weighted mean AOD and for nine individual stations located at upper (Karachi, Multan, Lahore), central (Delhi, Kanpur, Varanasi, Patna) and lower IGP (Kolkata, Dhaka). A comparatively high aerosol loading (AOD: 0.50 ± 0.25) was evident over IGP with a statistically insignificant increasing trend of 0.002 year-1. Analysis highlights the existing spatial and temporal gradients in aerosol loading with stations over central IGP like Varanasi (decadal mean AOD±SD; 0.67 ± 0.28) and Patna (0.65 ± 0.30) exhibit the highest AOD, followed by stations over lower IGP (Kolkata: 0.58 ± 0.21; Dhaka: 0.60 ± 0.24), with a statistically significant increasing trend (0.0174-0.0206 year-1). In contrast, stations over upper IGP reveal a comparatively low aerosol loading, having an insignificant increasing trend. Variation in AOD across IGP is found to be mainly influenced by seasonality and topography. A distinct "aerosol pool" region over eastern part of Ganges plain is identified, where meteorology, topography, and aerosol sources favor the persistence of airborne particulates. A strong seasonality in aerosol loading and types is also witnessed, with high AOD and dominance of fine particulates over central to lower IGP, especially during post-monsoon and winter. The time series analyses by autoregressive integrated moving average (ARIMA) indicate contrasting patterns in randomness of AOD over individual stations with better performance especially over central IGP. Concentration weighted trajectory analyses identify the crucial contributions of western dry regions and partial contributions from

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. Quantifying the climatological cloud-free direct radiative forcing of aerosol over the Red Sea

    KAUST Repository

    Brindley, Helen

    2015-04-01

    A combination of ground-based and satellite observations are used, in conjunction with column radiative transfer modelling, to assess the climatological aerosol loading and quantify its corresponding cloud-free direct radiative forcing (DRF) over the Red Sea. While there have been campaigns designed to probe aerosol-climate interactions over much of the world, relatively little attention has been paid to this region. Because of the remoteness of the area, satellite retrievals provide a crucial tool for assessing aerosol loading over the Sea. However, agreement between aerosol properties inferred from measurements from different instruments, and even in some cases from the same measurements using different retrieval algorithms can be poor, particularly in the case of mineral dust. Ground based measurements which can be used to evaluate retrievals are thus highly desirable. Here we take advantage of ship-based sun-photometer micro-tops observations gathered from a series of cruises which took place across the Red Sea during 2011 and 2013. To our knowledge these data represent the first set of detailed aerosol measurements from the Sea. They thus provide a unique opportunity to assess the performance of satellite retrieval algorithms in this region. Initially two aerosol optical depth (AOD) retrieval algorithms developed for the MODerate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) instruments are evaluated via comparison with the co-located cruise observations. These show excellent agreement, with correlations typically better than 0.9 and very small root-mean-square and bias differences. Calculations of radiative fluxes and DRF along one of the cruises using the observed aerosol and meteorological conditions also show good agreement with co-located estimates from the Geostationary Earth Radiation Budget (GERB) instrument if the aerosol asymmetry parameter is adjusted to account for the presence of large

  15. 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

  16. Climatology and energy budget of the northern hemisphere middle stratosphere during 1972

    Energy Technology Data Exchange (ETDEWEB)

    Tahnk, W R [Air Force Geophysics Lab., Bedforo, MA; Newell, R E

    1975-01-01

    The 10-2 mb (approx. 30 to 40 km) layer of the atmosphere in winter receives energy from two different sources: mechanical energy is carried up from the troposphere and lower stratosphere while energy is generated in situ by the gradients of radiative heating and cooling. We show here from data for 1972 that the latter primarily governs the energy budget of the middle stratosphere in early winter while the former becomes of comparable size, and often dominates, in the middle and late winter. Radiative energy sources for the summer hemisphere are very small, as there is considerable compensation between solar heating through ozone absorption and infrared cooling by carbon dioxide and ozone. Standing and travelling waves are quite clear-cut at 5 and 2 mb in winter, as much of the chaos of lower regions is filtered out in the lower stratosphere; the standing waves at 2 mb may reflect surface properties more effectively than flow patterns at lower levels. A westward-travelling wave, with a period of about a month, was evident in early 1972.

  17. 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

  18. 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.

  19. A global climatology of stratospheric gravity waves from Atmospheric Infrared Sounder observations

    Science.gov (United States)

    Hoffmann, Lars; Xue, Xianghui; Alexander, M. Joan

    2014-05-01

    We present the results of a new study that aims on the detection and classification of `hotspots' of stratospheric gravity waves on a global scale. The analysis is based on a nine-year record (2003 to 2011) of radiance measurements by the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite. We detect the presence of stratospheric gravity waves based on 4.3 micron brightness temperature variances. Our method is optimized for peak events, i.e., strong gravity wave events for which the local variance considerably exceeds background levels. We estimated the occurrence frequencies of these peak events for different seasons and time of day and used the results to find local maxima of gravity wave activity. In addition, we use AIRS radiances at 8.1 micron to simultaneously detect convective events, including deep convection in the tropics and mesoscale convective systems at mid latitudes. We classified the gravity waves according to their sources, based on seasonal occurrence frequencies for convection and by means of topographic data. Our study reproduces well-known hotspots of gravity waves, e.g., the mountain wave hotspots at the Andes and the Antarctic Peninsula or the convective hotspot during the thunderstorm season over the North American Great Plains. However, the high horizontal resolution of the AIRS observations also helped us to locate several smaller hotspots, which were partly unknown or poorly studied so far. Most of these smaller hotspots are found near orographic features like small mountain ranges, in coastal regions, in desert areas, or near isolated islands. This new study will help to select the most promising regions and seasons for future observational studies of gravity waves. Reference: Hoffmann, L., X. Xue, and M. J. Alexander, A global view of stratospheric gravity wave hotspots located with Atmospheric Infrared Sounder observations, J. Geophys. Res., 118, 416-434, doi:10.1029/2012JD018658, 2013.

  20. Exploring Climatology and Long-Term Variations of Aerosols from NASA Reanalysis MERRA-2 with Giovanni

    Science.gov (United States)

    Shen, Suhung; Ostrenga, Dana; Vollmer, Bruce; Li, Zhanqing

    2016-01-01

    Dust plays important roles in energy cycle and climate variations. The dust deposition is the major source of iron in the open ocean, which is an essential micronutrient for phytoplankton growth and therefore may influence the ocean uptake of atmospheric CO2. Mineral dust can also act as fertilizer for forests over long time periods. Over 35 years of simulated global aerosol products from NASA atmospheric reanalysis, second Modern-Era Retrospective analysis for Research and Applications (MERRA-2) are available from NASA Goddard Earth Science Data and Information Services Center (GES DISC). The MERRA-2 covers the period 1980-present, continuing as an ongoing climate analysis. Aerosol assimilation is included throughout the period, using MODIS, MISR, AERONET, and AVHRR (in the pre-EOS period). The aerosols are assimilated by using MERRA-2 aerosol model, which interact directly with the radiation parameterization, and radiatively coupled with atmospheric model dynamics in the Goddard Earth Observing System Model, Version 5 (GEOS-5). Dust deposition data along with other major aerosol compositions (e.g. black carbon, sea salt, and sulfate, etc.) are simulated as dry and wet deposition, respectively. The hourly and monthly data are available at spatial resolution of 0.5ox0.625o (latitude x longitude). Quick data exploration of climatology and interannual variations of MERRA-2 aerosol can be done through the online visualization and analysis tool, Giovanni. This presentation, using dust deposition as an example, demonstrates a number of MERRA-2 data services at GES DISC. Global distributions of dust depositions, and their seasonal and inter-annual variations are investigated from MERRA-2 monthly aerosol products.

  1. 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.

  2. Stratospheric ozone climatology and variability over a southern subtropical site: Reunion Island (21° S; 55° E

    Directory of Open Access Journals (Sweden)

    V. Sivakumar

    2007-11-01

    Full Text Available The study presents the climatological characteristics of stratospheric ozone observed over Reunion Island using in-situ (ozonesonde and SAOZ and satellite (UARS-HALOE, SAGE-II and TOMS measurements. It uses co-localised ozonesondes (from September 1992 to February 2005 and SAOZ measurements (from January 1993 to December 2004, SAGE-II data from October 1984 to February 1999 (~15 years, HALOE data from January 1991 to February 2005 (~15 years, and NIMBUS/TOMS data from January 1978 to December 2004 (27 years. The satellite measurements correspond to overpasses located nearby Reunion Island (21° S; 55° E. The height profiles of ozone concentration obtained from ozonesonde (0.5–29.5 km show less bias in comparison with the HALOE and SAGE-II measurements. Though, the satellite (HALOE and SAGE-II measurements underestimate the tropospheric ozone, they are in good agreement for the heights above 15 km. The bias between the measurements and the normalized ozone profile constructed from the ozonesonde and SAGE-II satellite measurement shows that the SAGE-II measurements are more accurate than the HALOE measurements in the lower stratosphere. The monthly variation of ozone concentration derived from ozonesonde and HALOE shows a nearly annual cycle with a maximum concentration during winter/spring and minimum concentration during summer/autumn months. The time evolution of total column ozone obtained from TOMS, SAOZ and the one computed from ozonesonde and SAGE-II, exhibits similar behaviour with analogous trends as above. The TOMS variation displays a higher value of total column ozone of about 3–5 DU (10% in comparison with the SAOZ and the integrated ozone from ozonesonde and SAGE-II.

  3. 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.

  4. Aerosol climatology over the Mexico City basin: Characterization of optical properties

    Science.gov (United States)

    Carabali, Giovanni; Estévez, Héctor Raúl; Valdés-Barrón, Mauro; Bonifaz-Alfonzo, Roberto; Riveros-Rosas, David; Velasco-Herrera, Víctor Manuel; Vázquez-Gálvez, Felipe Adrián

    2017-09-01

    Climatology of Aerosol Optical Depth (AOD), Single Scattering Albedo (SSA), and aerosol particle-size distribution were analyzed using a 15-year (1999-2014) dataset from AErosol RObotic NETwork (AERONET) observations over the Mexico City (MC) basin. The atmosphere over this site is dominated by two main aerosol types, represented by urban/industrial pollution and biomass-burning particles. Due to the specific meteorological conditions within the basin, seasons are usually classified into three as follows: Dry Winter (DW) (November-February); Dry Spring (DS) (March-April), and the RAiny season (RA) (May-October), which are mentioned throughout this article. Using a CIMEL sun photometer, we conducted continuous observations over the MC urban area from January 1999 to December 2014. Aerosol Optical Depth (AOD), Ångström exponent (α440-870), Single Scattering Albedo (SSA), and aerosol particle-size distribution were derived from the observational data. The overall mean AOD500 during the 1999-2014 period was 0.34 ± 0.07. The monthly mean AOD reached a maximal value of 0.49 in May and a minimal value of 0.27 in February and March. The average α440-870 value for the period studied was 1.50 ± 0.16. The monthly average of α440-870 reached a minimal value of 1.32 in August and a maximal value of 1.61 in May. Average SSA at 440 nm was 0.89 throughout the observation period, indicating that aerosols over Mexico City are composed mainly of absorptive particles. Concentrations of fine- and coarse-mode aerosols over MC were highest in DS season compared with other seasons, especially for particles with radii measuring between 0.1 and 0.2 μm. Results from the Spectral De-convolution Algorithm (SDA) show that fine-mode aerosols dominated AOD variability in MC. In the final part of this article, we present a classification of aerosols in MC by using the graphical method proposed by Gobbi et al. (2007), which is based on the combined analysis of α and its spectral curvature

  5. 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.

  6. Long-term dust climatology in the western United States reconstructed from routine aerosol ground monitoring

    Directory of Open Access Journals (Sweden)

    D. Q. Tong

    2012-06-01

    Full Text Available This study introduces an observation-based dust identification approach and applies it to reconstruct long-term dust climatology in the western United States. Long-term dust climatology is important for quantifying the effects of atmospheric aerosols on regional and global climate. Although many routine aerosol monitoring networks exist, it is often difficult to obtain dust records from these networks, because these monitors are either deployed far away from dust active regions (most likely collocated with dense population or contaminated by anthropogenic sources and other natural sources, such as wildfires and vegetation detritus. Here we propose an approach to identify local dust events relying solely on aerosol mass and composition from general-purpose aerosol measurements. Through analyzing the chemical and physical characteristics of aerosol observations during satellite-detected dust episodes, we select five indicators to be used to identify local dust records: (1 high PM10 concentrations; (2 low PM2.5/PM10 ratio; (3 higher concentrations and percentage of crustal elements; (4 lower percentage of anthropogenic pollutants; and (5 low enrichment factors of anthropogenic elements. After establishing these identification criteria, we conduct hierarchical cluster analysis for all validated aerosol measurement data over 68 IMPROVE sites in the western United States. A total of 182 local dust events were identified over 30 of the 68 locations from 2000 to 2007. These locations are either close to the four US Deserts, namely the Great Basin Desert, the Mojave Desert, the Sonoran Desert, and the Chihuahuan Desert, or in the high wind power region (Colorado. During the eight-year study period, the total number of dust events displays an interesting four-year activity cycle (one in 2000–2003 and the other in 2004–2007. The years of 2003, 2002 and 2007 are the three most active dust periods, with 46, 31 and 24

  7. 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

  8. An aerosol optical depth climatology for NOAA's national surface radiation budget network (SURFRAD)

    Science.gov (United States)

    Augustine, John A.; Hodges, Gary B.; Dutton, Ellsworth G.; Michalsky, Joseph J.; Cornwall, Christopher R.

    2008-06-01

    A series of algorithms developed to process spectral solar measurements for aerosol optical depth (AOD) for the National Oceanic and Atmospheric Administration's (NOAA) national surface radiation budget network (SURFRAD) is summarized, and decadal results are presented. AOD is a measure of the extinction of the Sun's beam due to aerosols. Daily files of AOD for five spectral measurements in the visible and near-infrared have been produced for 1997-2006. Comparisons of SURFRAD daily AOD averages to NASA's Aerosol Robotic Network product at two of the stations were generally good. An AOD climatology for each SURFRAD station is presented as an annual time series of composite monthly means that represents a typical intra-annual AOD variation. Results are similar to previous U.S. climatologies in that the highest AOD magnitude and greatest variability occur in summer, the lowest AOD levels are in winter, and geographically, the highest-magnitude AOD is in the eastern United States. Springtime Asian dust intrusions show up as a secondary maximum at the western stations. A time series of nationwide annual means shows that 500-nm AOD has decreased over the United States by about 0.02 AOD units over the 10-year period. However, this decline is not statistically significant nor geographically consistent within the country. The eastern U.S. stations and westernmost station at Desert Rock, Nevada, show decreasing AOD, whereas the other two western stations show an increase that is attributed to an upsurge in wildfire activity in the last half of the decade.

  9. 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).

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

    Directory of Open Access Journals (Sweden)

    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.

  11. 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.

  12. 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.

  13. Climatology and trends in the forcing of the stratospheric zonal-mean flow

    Directory of Open Access Journals (Sweden)

    E. Monier

    2011-12-01

    Full Text Available The momentum budget of the Transformed Eulerian-Mean (TEM equation is calculated using the European Centre for Medium-Range Weather Forecasts (ECMWF reanalysis (ERA-40 and the National Centers for Environmental Prediction (NCEP Reanalysis 2 (R-2. This study outlines the considerable contribution of unresolved waves, deduced to be gravity waves, to the forcing of the zonal-mean flow. A trend analysis, from 1980 to 2001, shows that the onset and break down of the Northern Hemisphere (NH stratospheric polar night jet has a tendency to occur later in the season in the more recent years. This temporal shift follows long-term changes in planetary wave activity that are mainly due to synoptic waves, with a lag of one month. In the Southern Hemisphere (SH, the polar vortex shows a tendency to persist further into the SH summertime. This also follows a statistically significant decrease in the intensity of the stationary EP flux divergence over the 1980–2001 period. Ozone depletion is well known for strengthening the polar vortex through the thermal wind balance. However, the results of this work show that the SH polar vortex does not experience any significant long-term changes until the month of December, even though the intensification of the ozone hole occurs mainly between September and November. This study suggests that the decrease in planetary wave activity in November provides an important feedback to the zonal wind as it delays the breakdown of the polar vortex. In addition, the absence of strong eddy feedback before November explains the lack of significant trends in the polar vortex in the SH early spring. A long-term weakening in the Brewer-Dobson (B-D circulation in the polar region is identified in the NH winter and early spring and during the SH late spring and is likely driven by the decrease in planetary wave activity previously mentioned. During the rest of the year, there are large discrepancies in the representation of the B

  14. 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

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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.)

  6. Trends in aerosol optical depth in the Russian Arctic and their links with synoptic climatology

    International Nuclear Information System (INIS)

    Shahgedanova, Maria; Lamakin, Mikhail

    2005-01-01

    Temporal and spatial variability of aerosol optical depth (AOD) are examined using observations of direct solar radiation in the Eurasian Arctic for 1940-1990. AOD is estimated using empirical methods for 14 stations located between 66.2 deg N and 80.6 deg N, from the Kara Sea to the Chukchi Sea. While AOD exhibits a well-known springtime maximum and summertime minimum at all stations, atmospheric turbidity is higher in spring in the western (Kara-Laptev) part of the Eurasian Arctic. Between June and August, the eastern (East Siberian-Chukchi) sector experiences higher transparency than the western part. A statistically significant positive trend in AOD was observed in the Kara-Laptev sector between the late 1950s and the early 1980s predominantly in spring when pollution-derived aerosol dominates the Arctic atmosphere but not in the eastern sector. Although all stations are remote, those with positive trends are located closer to the anthropogenic sources of air pollution. By contrast, a widespread decline in AOD was observed between 1982 and 1990 in the eastern Arctic in spring but was limited to two sites in the western Arctic. These results suggest that the post-1982 decline in anthropogenic emissions in Europe and the former Soviet Union has had a limited effect on aerosol load in the Arctic. The post-1982 negative trends in AOD in summer, when marine aerosol is present in the atmosphere, were more common in the west. The relationships between AOD and atmospheric circulation are examined using a synoptic climatology approach. In spring, AOD depends primarily on the strength and direction of air flow. Thus strong westerly and northerly flows result in low AOD values in the East Siberian-Chukchi sector. By contrast, strong southerly flow associated with the passage of depressions results in high AOD in the Kara-Laptev sector and trajectory analysis points to the contribution of industrial regions of the sub-Arctic. In summer, low pressure gradient or

  7. 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)

  8. Direct and semi-direct effects of aerosol climatologies on long-term climate simulations over Europe

    Science.gov (United States)

    Schultze, Markus; Rockel, Burkhardt

    2017-08-01

    This study compares the direct and semi-direct aerosol effects of different annual cycles of tropospheric aerosol loads for Europe from 1950 to 2009 using the regional climate model COSMO-CLM, which is laterally forced by reanalysis data and run using prescribed, climatological aerosol optical properties. These properties differ with respect to the analysis strategy and the time window, and are then used for the same multi-decadal period. Five simulations with different aerosol loads and one control simulation without any tropospheric aerosols are integrated and compared. Two common limitations of our simulation strategy, to fully assess direct and semi-direct aerosol effects, are the applied observed sea surface temperatures and sea ice conditions, and the lack of short-term variations in the aerosol load. Nevertheless, the impact of different aerosol climatologies on common regional climate model simulations can be assessed. The results of all aerosol-including simulations show a distinct reduction in solar irradiance at the surface compared with that in the control simulation. This reduction is strongest in the summer season and is balanced primarily by a weakening of turbulent heat fluxes and to a lesser extent by a decrease in longwave emissions. Consequently, the seasonal mean surface cooling is modest. The temperature profile responses are characterized by a shallow near-surface cooling and a dominant warming up to the mid-troposphere caused by aerosol absorption. The resulting stabilization of stratification leads to reduced cloud cover and less precipitation. A decrease in cloud water and ice content over Central Europe in summer possibly reinforce aerosol absorption and thus strengthen the vertical warming. The resulting radiative forcings are positive. The robustness of the results was demonstrated by performing a simulation with very strong aerosol forcing, which lead to qualitatively similar results. A distinct added value over the default aerosol

  9. 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.

  10. 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)

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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%.

  16. 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.

  17. 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.

  18. The Southeastern Aerosol Research and Characterization (SEARCH) study: spatial variations and chemical climatology, 1999-2010.

    Science.gov (United States)

    Blanchard, C L; Hidy, G M; Tanenbaum, S; Edgerton, E S; Hartsell, B E

    2013-03-01

    The Southeastern Aerosol Research and Characterization (SEARCH) study, which has been in continuous operation from 1999 to 2012, was implemented to investigate regional and urban air pollution in the southeastern United States. With complementary data from other networks, the SEARCH measurements provide key knowledge about long-term urban/nonurban pollution contrasts and regional climatology affecting inland locations and sites along the Gulf of Mexico coastline. Analytical approaches ranging from comparisons of mean concentrations to the application of air mass trajectories and principal component analysis provide insight into local and area-wide pollution. Gases (carbon monoxide, sulfur dioxide, nitrogen oxides, ozone, and ammonia), fine particle mass concentration, and fine particle species concentrations (including sulfate, elementary carbon, and organic carbon) are affected by a combination of regional conditions and local emission sources. Urban concentrations in excess of regional baselines and intraurban variations of concentrations depend on source proximity, topography, and local meteorological processes. Regional-scale pollution events (95th percentile concentrations) involving more than 6 of the 8 SEARCH sites are rare (< 2% of days), while subregional events affecting 4-6 sites occur on approximately 10% of days. Regional and subregional events are characterized by widely coincident elevated concentrations of ozone, sulfate, and particulate organic carbon, driven by persistent synoptic-scale air mass stagnation and higher temperatures that favor formation of secondary species, mainly in the summer months. The meteorological conditions associated with regional stagnation do not favor long-range transport of polluted air masses during episodes. Regional and subregional pollution events frequently terminate with southward and eastward penetration of frontal systems, which may initially reduce air pollutant concentrations more inland than along the Gulf

  19. 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.

  20. 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

  1. 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.

  2. Quantifying the climatological cloud-free direct radiative forcing of aerosol over the Red Sea

    KAUST Repository

    Brindley, Helen; Osipov, Serega; Bantges, Richard; Smirnov, Alexander; Banks, Jamie; Levy, Robert; Prakash, P.-Jish; Stenchikov, Georgiy L.

    2015-01-01

    for assessing aerosol loading over the Sea. However, agreement between aerosol properties inferred from measurements from different instruments, and even in some cases from the same measurements using different retrieval algorithms can be poor, particularly

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. 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

  11. 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

  12. 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

  13. 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.

  14. An assessment of the quality of aerosol retrievals over the Red Sea and evaluation of the climatological cloud-free dust direct radiative effect in the region

    KAUST Repository

    Brindley, H.

    2015-10-20

    Ground-based and satellite observations are used in conjunction with the Rapid Radiative Transfer Model (RRTM) to assess climatological aerosol loading and the associated cloud-free aerosol direct radiative effect (DRE) over the Red Sea. Aerosol optical depth (AOD) retrievals from the Moderate Resolution Imaging Spectroradiometer and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) instruments are first evaluated via comparison with ship-based observations. Correlations are typically better than 0.9 with very small root-mean-square and bias differences. Calculations of the DRE along the ship cruises using RRTM also show good agreement with colocated estimates from the Geostationary Earth Radiation Budget instrument if the aerosol asymmetry parameter is adjusted to account for the presence of large particles. A monthly climatology of AOD over the Red Sea is then created from 5 years of SEVIRI retrievals. This shows enhanced aerosol loading and a distinct north to south gradient across the basin in the summer relative to the winter months. The climatology is used with RRTM to estimate the DRE at the top and bottom of the atmosphere and the atmospheric absorption due to dust aerosol. These climatological estimates indicate that although longwave effects can reach tens of W m−2, shortwave cooling typically dominates the net radiative effect over the Sea, being particularly pronounced in the summer, reaching 120 W m−2 at the surface. The spatial gradient in summertime AOD is reflected in the radiative effect at the surface and in associated differential heating by aerosol within the atmosphere above the Sea. This asymmetric effect is expected to exert a significant influence on the regional atmospheric and oceanic circulation.

  15. An assessment of the quality of aerosol retrievals over the Red Sea and evaluation of the climatological cloud-free dust direct radiative effect in the region

    KAUST Repository

    Brindley, H.; Osipov, Sergey; Bantges, R.; Smirnov, A.; Banks, J.; Levy, R.; Jish Prakash, P.; Stenchikov, Georgiy L.

    2015-01-01

    Ground-based and satellite observations are used in conjunction with the Rapid Radiative Transfer Model (RRTM) to assess climatological aerosol loading and the associated cloud-free aerosol direct radiative effect (DRE) over the Red Sea. Aerosol optical depth (AOD) retrievals from the Moderate Resolution Imaging Spectroradiometer and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) instruments are first evaluated via comparison with ship-based observations. Correlations are typically better than 0.9 with very small root-mean-square and bias differences. Calculations of the DRE along the ship cruises using RRTM also show good agreement with colocated estimates from the Geostationary Earth Radiation Budget instrument if the aerosol asymmetry parameter is adjusted to account for the presence of large particles. A monthly climatology of AOD over the Red Sea is then created from 5 years of SEVIRI retrievals. This shows enhanced aerosol loading and a distinct north to south gradient across the basin in the summer relative to the winter months. The climatology is used with RRTM to estimate the DRE at the top and bottom of the atmosphere and the atmospheric absorption due to dust aerosol. These climatological estimates indicate that although longwave effects can reach tens of W m−2, shortwave cooling typically dominates the net radiative effect over the Sea, being particularly pronounced in the summer, reaching 120 W m−2 at the surface. The spatial gradient in summertime AOD is reflected in the radiative effect at the surface and in associated differential heating by aerosol within the atmosphere above the Sea. This asymmetric effect is expected to exert a significant influence on the regional atmospheric and oceanic circulation.

  16. 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.

  17. Aerosol climatology and planetary boundary influence at the Jungfraujoch analyzed by synoptic weather types

    OpenAIRE

    M. Collaud Coen; E. Weingartner; M. Furger; S. Nyeki; A. S. H. Prévôt; M. Steinbacher; U. Baltensperger

    2011-01-01

    Fourteen years of meteorological parameters, aerosol variables (absorption and scattering coefficients, aerosol number concentration) and trace gases (CO, NOx, SO2) measured at the Jungfraujoch (JFJ, 3580 m a.s.l.) have been analyzed as a function of different synoptic weather types. The Schüepp synoptic weather type of the Alps (SYNALP) classification from the Alpine Weather Statistics (AWS) was used to define the synoptic meteorology over the wh...

  18. Climatological aspects of aerosol physical characteristics in Tunisia deduced from sun photometric measurements.

    Science.gov (United States)

    Chaâbane, Mabrouk; Azri, Chafai; Medhioub, Khaled

    2012-01-01

    Atmospheric and climatic data measured at Thala site (Tunisia) for a long-time period (1977-2001) are used to analyse the monthly, seasonal, and annual variations of the aerosol optical depth at 1 μm wavelength. We have shown that aerosol and microphysical properties and the dominating aerosol types depend on seasons. A comparison of the seasonal cycle of aerosol optical characteristics at Thala site showed that the contribution of long-range transported particles is expected to be larger in summer as a consequence of the weather stability typical of this season. Also, the winter decrease in atmospheric turbidity may result from increases in relative humidity and decreases in temperature, leading to increased particle size and mass and increased fall and deposition velocities. The spring and autumn weather patterns usually carry fine dust and sand particles for the desert area to Thala region. The annual behaviour of the aerosol optical depth recorded a period of stead increase started in 1986 until 2001. Trends in atmospheric turbidity after 1988 could be explained other ways by the contribution of the eruption of Mount Pinatubo in 1991 and by local or regional changes in climate or in aerosol emissions.

  19. 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.

  20. Aerosol climatology and planetary boundary influence at the Jungfraujoch analyzed by synoptic weather types

    Directory of Open Access Journals (Sweden)

    M. Collaud Coen

    2011-06-01

    Full Text Available Fourteen years of meteorological parameters, aerosol variables (absorption and scattering coefficients, aerosol number concentration and trace gases (CO, NOx, SO2 measured at the Jungfraujoch (JFJ, 3580 m a.s.l. have been analyzed as a function of different synoptic weather types. The Schüepp synoptic weather type of the Alps (SYNALP classification from the Alpine Weather Statistics (AWS was used to define the synoptic meteorology over the whole Swiss region. The seasonal contribution of each synoptic weather type to the aerosol concentration was deduced from the aerosol annual cycles while the planetary boundary layer (PBL influence was estimated by means of the diurnal cycles. Since aerosols are scavenged by precipitation, the diurnal cycle of the CO concentration was also used to identify polluted air masses. SO2 and NOx concentrations were used as precursor tracers for new particle formation and growth, respectively. The aerosol optical parameters and number concentration show elevated loadings during advective weather types during the December–March period and for the convective anticyclonic and convective indifferent weather types during the April–September period. This study confirms the consensus view that the JFJ is mainly influenced by the free troposphere during winter and by injection of air parcels from the PBL during summer. A more detailed picture is, however, drawn where the JFJ is completely influenced by free tropospheric air masses in winter during advective weather types and largely influenced by the PBL also during the night in summer during the subsidence weather type. Between these two extreme situations, the PBL influence at the JFJ depends on both the time of year and the synoptic weather type. The fraction of PBL air transported to the JFJ was estimated by the relative increase of the specific humidity and CO.

  1. 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

  2. Aerosol climatology over South Africa based on 10 years of Multiangle Imaging Spectroradiometer (MISR) data

    CSIR Research Space (South Africa)

    Tesfaye, M

    2011-10-01

    Full Text Available ; Eck et al., 2003; Freiman and Piketh, 2003; Ichoku et al., 2003; Ross et al., 2003; Liu, 2005; Winkler et al., 2008; Queface et al., 2011]. Those studies focused on a limited time scale, dur- ing biomass�burning seasons, and on the northern parts... to provide further information on particle size distribution of aerosols in the solar spectrum. Several authors have discussed how the spectral variation of a can provide information about the aerosol size distribution [e.g., Nakajima et al., 1986...

  3. 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.

  4. 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.

  5. Validation of Long-Term Global Aerosol Climatology Project Optical Thickness Retrievals Using AERONET and MODIS Data

    Science.gov (United States)

    Geogdzhayev, Igor V.; Mishchenko, Michael I.

    2015-01-01

    A comprehensive set of monthly mean aerosol optical thickness (AOT) data from coastal and island AErosol RObotic NETwork (AERONET) stations is used to evaluate Global Aerosol Climatology Project (GACP) retrievals for the period 1995-2009 during which contemporaneous GACP and AERONET data were available. To put the GACP performance in broader perspective, we also compare AERONET and MODerate resolution Imaging Spectroradiometer (MODIS) Aqua level-2 data for 2003-2009 using the same methodology. We find that a large mismatch in geographic coverage exists between the satellite and ground-based datasets, with very limited AERONET coverage of open-ocean areas. This is especially true of GACP because of the smaller number of AERONET stations at the early stages of the network development. Monthly mean AOTs from the two over-the-ocean satellite datasets are well-correlated with the ground-based values, the correlation coefficients being 0.81-0.85 for GACP and 0.74-0.79 for MODIS. Regression analyses demonstrate that the GACP mean AOTs are approximately 17%-27% lower than the AERONET values on average, while the MODIS mean AOTs are 5%-25% higher. The regression coefficients are highly dependent on the weighting assumptions (e.g., on the measure of aerosol variability) as well as on the set of AERONET stations used for comparison. Comparison of over-the-land and over-the-ocean MODIS monthly mean AOTs in the vicinity of coastal AERONET stations reveals a significant bias. This may indicate that aerosol amounts in coastal locations can differ significantly from those in adjacent open-ocean areas. Furthermore, the color of coastal waters and peculiarities of coastline meteorological conditions may introduce biases in the GACP AOT retrievals. We conclude that the GACP and MODIS over-the-ocean retrieval algorithms show similar ranges of discrepancy when compared to available coastal and island AERONET stations. The factors mentioned above may limit the performance of the

  6. Modelling the background aerosol climatologies (1989-2010) for the Mediterranean basin

    Science.gov (United States)

    Jimenez-Guerrero, Pedro; Jerez, Sonia

    2014-05-01

    Aerosol levels and composition are influenced by multiple atmospheric physico-chemical processes that can affect them from its release point (as primary aerosol), or via gas-to-particle conversion processes that give rise to secondary aerosols. The contribution of the various aerosol sources, the role of long-range transport and the contribution of primary and secondary particulate matter to the ambient aerosol concentrations over Europe are not well known (Kulmala et al., 2009). Focusing on the Mediterranean, Querol et al. (2009) point out that there is a lack of studies on the variability of particulate matter (PM) along the Mediterranean basin, necessary for understanding the special features that differentiate aerosol processes between the western, eastern and central Mediterranean basins. In this perspective, modelling systems based on state-of-science chemistry transport models (CTMs) are fundamental elements to investigate the transport and chemistry of pollutants behaviour at different scales and to assess the impact of emissions in aerosol levels and composition. Therefore, this study aims to summarise the results on the levels and chemical composition of aerosols along the Mediterranean basin, highlighting the marked gradient between the western-central-eastern coasts. Special attention is paid to the analysis of the seasonality of PM composition and levels. For this purpose, the regional modelling system WRF-CHIMERE-EMEP has been implemented for conducting a full transient simulation for the ERA-Interim period (1989-2010) using year-to-year changing EMEP emissions. The domain of study covers Europe with a horizontal resolution of 25 km and a vertical resolution of 23 layers in the troposphere; however the analysis focuses on the Mediterranean area. The PM levels and composition are compared to the measured values reported by the EMEP network, showing a good agreement with observations for both western and eastern Mediterranean. The modelling results for

  7. 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

  8. 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

  9. Response to Toward Unified Satellite Climatology of Aerosol Properties. 3; MODIS versus MISR versus AERONET

    Science.gov (United States)

    Kahn, Ralph A.; Garay, Michael J.; Nelson, David L.; Levy, Robert C.; Bull, Michael A.; Diner, David J.; Martonchik, John V.; Hansen, Earl G.; Remer, Lorraine A.; Tanre, Didler

    2010-01-01

    A recent paper by Mishchenko et al. compares near-coincident MISR, MODIS, and AERONET aerosol optical depth (AOD), and gives a much less favorable impression of the utility of the satellite products than that presented by the instrument teams and other groups. We trace the reasons for the differing pictures to whether known and previously documented limitations of the products are taken into account in the assessments. Specifically, the analysis approaches differ primarily in (1) the treatment of outliers, (2) the application of absolute vs. relative criteria for testing agreement, and (3) the ways in which seasonally varying spatial distributions of coincident retrievals are taken into account. Mishchenko et al. also do not distinguish between observational sampling differences and retrieval algorithm error. We assess the implications of the different analysis approaches, and cite examples demonstrating how the MISR and MODIS aerosol products have been applied successfully to a range of scientific investigations.

  10. Response to "Toward Unified Satellite Climatology of Aerosol Properties. 3. MODIS Versus MISR Versus AERONET"

    Science.gov (United States)

    Kahn, Ralph A.; Garay, Michael J.; Nelson, David L.; Levy, Robert C.; Bull, Michael A.; Diner, David J.; Martonchik, John V.; Hansen, Earl G.; Remer, Lorraine A.; Tanre, Didier

    2010-01-01

    A recent paper by Mishchenko et al. compares near-coincident MISR, MODIS, and AERONET aerosol optical depth (AOD) products, and reports much poorer agreement than that obtained by the instrument teams and others. We trace the reasons for the discrepancies primarily to differences in (1) the treatment of outliers, (2) the application of absolute vs. relative criteria for testing agreement, and (3) the ways in which seasonally varying spatial distributions of coincident retrievals are taken into account.

  11. 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

  12. Toward Unified Satellite Climatology of Aerosol Properties. 3. MODIS Versus MISR Versus AERONET

    Science.gov (United States)

    Mishchenko, Michael I.; Liu, Li; Geogdzhayev, Igor V.; Travis, Larry D.; Cairns, Brian; Lacis, Andrew A.

    2010-01-01

    We use the full duration of collocated pixel-level MODIS-Terra and MISR aerosol optical thickness (AOT) retrievals and level 2 cloud-screened quality-assured AERONET measurements to evaluate the likely individual MODIS and MISR retrieval accuracies globally over oceans and land. We show that the use of quality-assured MODIS AOTs as opposed to the use of all MODIS AOTs has little effect on the resulting accuracy. The MODIS and MISR relative standard deviations (RSTDs) with respect to AERONET are remarkably stable over the entire measurement record and reveal nearly identical overall AOT performances of MODIS and MISR over the entire suite of AERONET sites. This result is used to evaluate the likely pixel-level MODIS and MISR performances on the global basis with respect to the (unknown) actual AOTs. For this purpose, we use only fully compatible MISR and MODIS aerosol pixels. We conclude that the likely RSTDs for this subset of MODIS and MISR AOTs are 73% over land and 30% over oceans. The average RSTDs for the combined [AOT(MODIS)+AOT(MISR)]/2 pixel-level product are close to 66% and 27%, respectively, which allows us to recommend this simple blend as a better alternative to the original MODIS and MISR data. These accuracy estimates still do not represent the totality of MISR and quality-assured MODIS pixel-level AOTs since an unaccounted for and potentially significant source of errors is imperfect cloud screening. Furthermore, many collocated pixels for which one of the datasets reports a retrieval, whereas the other one does not may also be problematic.

  13. 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

  14. 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.

  15. A 10-year Ground-Based Radar Climatology of Convective Penetration of Stratospheric Intrusions and Associated Large-Scale Transport over the CONUS

    Science.gov (United States)

    Homeyer, C. R.

    2017-12-01

    Deep convection reaching the upper troposphere and lower stratosphere (UTLS) and its impact on atmospheric composition through rapid vertical transport of lower troposphere air and stratosphere-troposphere exchange has received increasing attention in the past 5-10 years. Most efforts focused on convection have been directed toward storms that reach and/or penetrate the coincident environmental lapse-rate tropopause. However, convection has also been shown to reach into large-scale stratospheric intrusions (depressions of stratospheric air lying well below the lapse-rate tropopause on the cyclonic side of upper troposphere jet streams). Such convective penetration of stratospheric intrusions is not captured by studies of lapse-rate tropopause-penetrating convection. In this presentation, it will be shown using hourly, high-quality mergers of ground-based radar observations from 2004 to 2013 in the contiguous United States (CONUS) and forward large-scale trajectory analysis that convective penetration of stratospheric intrusions: 1) is more frequent than lapse-rate tropopause-penetrating convection, 2) occurs over a broader area of the CONUS than lapse-rate tropopause-penetrating convection, and 3) can influence the composition of the lower stratosphere through large-scale advection of convectively influenced air to altitudes above the lapse-rate tropopause, which we find to occur for about 8.5% of the intrusion volumes reached by convection.

  16. Three-dimensional dust aerosol distribution and extinction climatology over northern Africa simulated with the ALADIN numerical prediction model from 2006 to 2010

    Science.gov (United States)

    Mokhtari, M.; Tulet, P.; Fischer, C.; Bouteloup, Y.; Bouyssel, F.; Brachemi, O.

    2015-08-01

    The seasonal cycle and optical properties of mineral dust aerosols in northern Africa were simulated for the period from 2006 to 2010 using the numerical atmospheric model ALADIN (Aire Limitée Adaptation dynamique Développement InterNational) coupled to the surface scheme SURFEX (SURFace EXternalisée). The particularity of the simulations is that the major physical processes responsible for dust emission and transport, as well as radiative effects, are taken into account on short timescales and at mesoscale resolution. The aim of these simulations is to quantify the dust emission and deposition, locate the major areas of dust emission and establish a climatology of aerosol optical properties in northern Africa. The mean monthly aerosol optical thickness (AOT) simulated by ALADIN is compared with the AOTs derived from the standard Dark Target (DT) and Deep Blue (DB) algorithms of the Aqua-MODIS (MODerate resolution Imaging Spectroradiometer) products over northern Africa and with a set of sun photometer measurements located at Banizoumbou, Cinzana, Soroa, Mbour and Cape Verde. The vertical distribution of dust aerosol represented by extinction profiles is also analysed using CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) observations. The annual dust emission simulated by ALADIN over northern Africa is 878 Tg year-1. The Bodélé Depression appears to be the main area of dust emission in northern Africa, with an average estimate of about 21.6 Tg year-1. The simulated AOTs are in good agreement with satellite and sun photometer observations. The positions of the maxima of the modelled AOTs over northern Africa match the observed positions, and the ALADIN simulations satisfactorily reproduce the various dust events over the 2006-2010 period. The AOT climatology proposed in this paper provides a solid database of optical properties and consolidates the existing climatology over this region derived from satellites, the AERONET network and regional climate

  17. 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.

  18. 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.

  19. 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.

  20. Climatology of the Aerosol Optical Depth by Components from the Multi-Angle Imaging Spectroradiometer (MISR) and Chemistry Transport Models

    Science.gov (United States)

    Lee, Huikyo; Kalashnikova, Olga V.; Suzuki, Kentaroh; Braverman, Amy; Garay, Michael J.; Kahn, Ralph A.

    2016-01-01

    The Multi-angle Imaging Spectroradiometer (MISR) Joint Aerosol (JOINT_AS) Level 3 product has provided a global, descriptive summary of MISR Level 2 aerosol optical depth (AOD) and aerosol type information for each month over 16+ years since March 2000. Using Version 1 of JOINT_AS, which is based on the operational (Version 22) MISR Level 2 aerosol product, this study analyzes, for the first time, characteristics of observed and simulated distributions of AOD for three broad classes of aerosols: spherical nonabsorbing, spherical absorbing, and nonspherical - near or downwind of their major source regions. The statistical moments (means, standard deviations, and skew-nesses) and distributions of AOD by components derived from the JOINT_AS are compared with results from two chemistry transport models (CTMs), the Goddard Chemistry Aerosol Radiation and Transport (GOCART) and SPectral RadIatioN-TrAnSport (SPRINTARS). Overall, the AOD distributions retrieved from MISR and modeled by GOCART and SPRINTARS agree with each other in a qualitative sense. Marginal distributions of AOD for each aerosol type in both MISR and models show considerable high positive skewness, which indicates the importance of including extreme AOD events when comparing satellite retrievals with models. The MISR JOINT_AS product will greatly facilitate comparisons between satellite observations and model simulations of aerosols by type.

  1. 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.

  2. 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".

  3. Measurement-based climatology of aerosol direct radiative effect, its sensitivities, and uncertainties from a background southeast US site

    Science.gov (United States)

    Sherman, James P.; McComiskey, Allison

    2018-03-01

    Aerosol optical properties measured at Appalachian State University's co-located NASA AERONET and NOAA ESRL aerosol network monitoring sites over a nearly four-year period (June 2012-Feb 2016) are used, along with satellite-based surface reflectance measurements, to study the seasonal variability of diurnally averaged clear sky aerosol direct radiative effect (DRE) and radiative efficiency (RE) at the top-of-atmosphere (TOA) and at the surface. Aerosol chemistry and loading at the Appalachian State site are likely representative of the background southeast US (SE US), home to high summertime aerosol loading and one of only a few regions not to have warmed during the 20th century. This study is the first multi-year ground truth DRE study in the SE US, using aerosol network data products that are often used to validate satellite-based aerosol retrievals. The study is also the first in the SE US to quantify DRE uncertainties and sensitivities to aerosol optical properties and surface reflectance, including their seasonal dependence.Median DRE for the study period is -2.9 W m-2 at the TOA and -6.1 W m-2 at the surface. Monthly median and monthly mean DRE at the TOA (surface) are -1 to -2 W m-2 (-2 to -3 W m-2) during winter months and -5 to -6 W m-2 (-10 W m-2) during summer months. The DRE cycles follow the annual cycle of aerosol optical depth (AOD), which is 9 to 10 times larger in summer than in winter. Aerosol RE is anti-correlated with DRE, with winter values 1.5 to 2 times more negative than summer values. Due to the large seasonal dependence of aerosol DRE and RE, we quantify the sensitivity of DRE to aerosol optical properties and surface reflectance, using a calendar day representative of each season (21 December for winter; 21 March for spring, 21 June for summer, and 21 September for fall). We use these sensitivities along with measurement uncertainties of aerosol optical properties and surface reflectance to calculate DRE uncertainties. We also estimate

  4. 13-month climatology of the aerosol hygroscopicity at the free tropospheric site Jungfraujoch (3580 m a.s.l.

    Directory of Open Access Journals (Sweden)

    L. Kammermann

    2010-11-01

    Full Text Available A hygroscopicity tandem differential mobility analyzer (HTDMA was operated at the high-alpine site Jungfraujoch in order to characterize the hygroscopic diameter growth factors of the free tropospheric Aitken and accumulation mode aerosol. More than ~5000 h of valid data were collected for the dry diameters D0 = 35, 50, 75, 110, 165, and 265 nm during the 13-month measurement period from 1 May 2008 through 31 May 2009. No distinct seasonal variability of the hygroscopic properties was observed. Annual mean hygroscopic diameter growth factors (D/D0 at 90% relative humidity were found to be 1.34, 1.43, and 1.46 for D0 = 50, 110, and 265 nm, respectively. This size dependence can largely be attributed to the Kelvin effect because corresponding values of the hygroscopicity parameter κ are nearly independent of size. The mean hygroscopicity of the Aitken and accumulation mode aerosol at the free tropospheric site Jungfraujoch was found to be κ≈0.24 with little variability throughout the year.

    The impact of Saharan dust events, a frequent phenomenon at the Jungfraujoch, on aerosol hygroscopicity was shown to be negligible for D0<265 nm. Thermally driven injections of planetary boundary layer (PBL air, particularly observed in the early afternoon of summer days with convective anticyclonic weather conditions, lead to a decrease of aerosol hygroscopicity. However, the effect of PBL influence is not seen in the annual mean hygroscopicity data because the effect is small and those conditions (weather class, season and time of day with PBL influence are relatively rare.

    Aerosol hygroscopicity was found to be virtually independent of synoptic wind direction during advective weather situations, i.e. when horizontal motion of the atmosphere dominates over thermally driven convection. This indicates that the hygroscopic behavior of the aerosol observed at the

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. 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

  10. A global lightning parameterization based on statistical relationships among environmental factors, aerosols, and convective clouds in the TRMM climatology

    Science.gov (United States)

    Stolz, Douglas C.; Rutledge, Steven A.; Pierce, Jeffrey R.; van den Heever, Susan C.

    2017-07-01

    The objective of this study is to determine the relative contributions of normalized convective available potential energy (NCAPE), cloud condensation nuclei (CCN) concentrations, warm cloud depth (WCD), vertical wind shear (SHEAR), and environmental relative humidity (RH) to the variability of lightning and radar reflectivity within convective features (CFs) observed by the Tropical Rainfall Measuring Mission (TRMM) satellite. Our approach incorporates multidimensional binned representations of observations of CFs and modeled thermodynamics, kinematics, and CCN as inputs to develop approximations for total lightning density (TLD) and the average height of 30 dBZ radar reflectivity (AVGHT30). The results suggest that TLD and AVGHT30 increase with increasing NCAPE, increasing CCN, decreasing WCD, increasing SHEAR, and decreasing RH. Multiple-linear approximations for lightning and radar quantities using the aforementioned predictors account for significant portions of the variance in the binned data set (R2 ≈ 0.69-0.81). The standardized weights attributed to CCN, NCAPE, and WCD are largest, the standardized weight of RH varies relative to other predictors, while the standardized weight for SHEAR is comparatively small. We investigate these statistical relationships for collections of CFs within various geographic areas and compare the aerosol (CCN) and thermodynamic (NCAPE and WCD) contributions to variations in the CF population in a partial sensitivity analysis based on multiple-linear regression approximations computed herein. A global lightning parameterization is developed; the average difference between predicted and observed TLD decreases from +21.6 to +11.6% when using a hybrid approach to combine separate approximations over continents and oceans, thus highlighting the need for regionally targeted investigations in the future.

  11. A 4-D Climatology (1979-2009) of the Monthly Tropospheric Aerosol Optical Depth Distribution over the Mediterranean Region from a Comparative Evaluation and Blending of Remote Sensing and Model Products

    Science.gov (United States)

    Nabat, P.; Somot, S.; Mallet, M.; Chiapello, I; Morcrette, J. J.; Solomon, F.; Szopa, S.; Dulac, F; Collins, W.; Ghan, S.; hide

    2013-01-01

    Since the 1980s several spaceborne sensors have been used to retrieve the aerosol optical depth (AOD) over the Mediterranean region. In parallel, AOD climatologies coming from different numerical model simulations are now also available, permitting to distinguish the contribution of several aerosol types to the total AOD. In this work, we perform a comparative analysis of this unique multiyear database in terms of total AOD and of its apportionment by the five main aerosol types (soil dust, seasalt, sulfate, black and organic carbon). We use 9 different satellite-derived monthly AOD products: NOAA/AVHRR, SeaWiFS (2 products), TERRA/MISR, TERRA/MODIS, AQUA/MODIS, ENVISAT/MERIS, PARASOL/POLDER and MSG/SEVIRI, as well as 3 more historical datasets: NIMBUS7/CZCS, TOMS (onboard NIMBUS7 and Earth- Probe) and METEOSAT/MVIRI. Monthly model datasets include the aerosol climatology from Tegen et al. (1997), the climate-chemistry models LMDz-OR-INCA and RegCM-4, the multi-model mean coming from the ACCMIP exercise, and the reanalyses GEMS and MACC. Ground-based Level- 2 AERONET AOD observations from 47 stations around the basin are used here to evaluate the model and satellite data. The sensor MODIS (on AQUA and TERRA) has the best average AOD scores over this region, showing a relevant spatio-temporal variability and highlighting high dust loads over Northern Africa and the sea (spring and summer), and sulfate aerosols over continental Europe (summer). The comparison also shows limitations of certain datasets (especially MERIS and SeaWiFS standard products). Models reproduce the main patterns of the AOD variability over the basin. The MACC reanalysis is the closest to AERONET data, but appears to underestimate dust over Northern Africa, where RegCM-4 is found closer to MODIS thanks to its interactive scheme for dust emissions. The vertical dimension is also investigated using the CALIOP instrument. This study confirms differences of vertical distribution between dust

  12. A 4-D climatology (1979–2009 of the monthly tropospheric aerosol optical depth distribution over the Mediterranean region from a comparative evaluation and blending of remote sensing and model products

    Directory of Open Access Journals (Sweden)

    P. Nabat

    2013-05-01

    Full Text Available Since the 1980s several spaceborne sensors have been used to retrieve the aerosol optical depth (AOD over the Mediterranean region. In parallel, AOD climatologies coming from different numerical model simulations are now also available, permitting to distinguish the contribution of several aerosol types to the total AOD. In this work, we perform a comparative analysis of this unique multi-year database in terms of total AOD and of its apportionment by the five main aerosol types (soil dust, sea-salt, sulfate, black and organic carbon. We use 9 different satellite-derived monthly AOD products: NOAA/AVHRR, SeaWiFS (2 products, TERRA/MISR, TERRA/MODIS, AQUA/MODIS, ENVISAT/MERIS, PARASOL/POLDER and MSG/SEVIRI, as well as 3 more historical datasets: NIMBUS7/CZCS, TOMS (onboard NIMBUS7 and Earth-Probe and METEOSAT/MVIRI. Monthly model datasets include the aerosol climatology from Tegen et al. (1997, the climate-chemistry models LMDz-OR-INCA and RegCM-4, the multi-model mean coming from the ACCMIP exercise, and the reanalyses GEMS and MACC. Ground-based Level-2 AERONET AOD observations from 47 stations around the basin are used here to evaluate the model and satellite data. The sensor MODIS (on AQUA and TERRA has the best average AOD scores over this region, showing a relevant spatio-temporal variability and highlighting high dust loads over Northern Africa and the sea (spring and summer, and sulfate aerosols over continental Europe (summer. The comparison also shows limitations of certain datasets (especially MERIS and SeaWiFS standard products. Models reproduce the main patterns of the AOD variability over the basin. The MACC reanalysis is the closest to AERONET data, but appears to underestimate dust over Northern Africa, where RegCM-4 is found closer to MODIS thanks to its interactive scheme for dust emissions. The vertical dimension is also investigated using the CALIOP instrument. This study confirms differences of vertical distribution between

  13. SeaWiFS Deep Blue Aerosol Optical Thickness Monthly Level 3 Climatology Data Gridded at 0.5 Degrees V004

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS Deep Blue Level 3 Monthly Climatology Product contains monthly global climatology gridded (0.5 x 0.5 deg) data derived from SeaWiFS Deep Blue Level 3...

  14. General Climatology 3

    Science.gov (United States)

    Hartmann, Dennis L.

    General Climatology 3 is volume 3 of the series World Survey of Climatology, which consists of 15 volumes containing review articles on a broad range of topics. General Climatology 3 contains four chapters: ‘Human Bioclimatology,’ ‘Agricultural Climatology,’ ‘City Climate,’ and ‘Technical Climatology.’ Each of these chapters will be briefly described here.‘Human Bioclimatology,’ the first chapter, was authored by E. Flach and provides a survey of the effects on the human organism of the physical conditions at the earth's surface. It contains four main sections. A section entitled ‘Light and Life’ deals with the effects of solar radiation on man and contains much interesting information on the response of the human eye and human skin to radiation at various frequencies. ‘Air and Life’ discusses the composition of air and its effect on human health and performance, including discussions of the effects of altitude, aerosols, and noxious trace gases. ‘Temperature and Life’ discusses how the body responds to temperature and how it maintains its heat budget under the variety of conditions to which it falls subject and considerable discussion is given to objective ways to characterize air conditions that give an accurate measure of their impact on the body. This discussion leads naturally into the final section, ‘Bioclimatological Evaluation Systems,’ which addresses the problem of how to classify a particular site according to its overall suitability to human habitation.

  15. Climatology and long-term evolution of ozone and carbon monoxide in the upper troposphere–lower stratosphere (UTLS at northern midlatitudes, as seen by IAGOS from 1995 to 2013

    Directory of Open Access Journals (Sweden)

    Y. Cohen

    2018-04-01

    Full Text Available In situ measurements in the upper troposphere–lower stratosphere (UTLS have been performed in the framework of the European research infrastructure IAGOS (In-service Aircraft for a Global Observing System for ozone since 1994 and for carbon monoxide (CO since 2002. The flight tracks cover a wide range of longitudes in the northern extratropics, extending from the North American western coast (125° W to the eastern Asian coast (135° E and more recently over the northern Pacific Ocean. Several tropical regions are also sampled frequently, such as the Brazilian coast, central and southern Africa, southeastern Asia, and the western half of the Maritime Continent. As a result, a new set of climatologies for O3 (August 1994–December 2013 and CO (December 2001–December 2013 in the upper troposphere (UT, tropopause layer, and lower stratosphere (LS are made available, including gridded horizontal distributions on a semi-global scale and seasonal cycles over eight well-sampled regions of interest in the northern extratropics. The seasonal cycles generally show a summertime maximum in O3 and a springtime maximum in CO in the UT, in contrast to the systematic springtime maximum in O3 and the quasi-absence of a seasonal cycle of CO in the LS. This study highlights some regional variabilities in the UT, notably (i a west–east difference of O3 in boreal summer with up to 15 ppb more O3 over central Russia compared with northeast America, (ii a systematic west–east gradient of CO from 60 to 140° E, especially noticeable in spring and summer with about 5 ppb by 10 degrees longitude, (iii a broad spring/summer maximum of CO over northeast Asia, and (iv a spring maximum of O3 over western North America. Thanks to almost 20 years of O3 and 12 years of CO measurements, the IAGOS database is a unique data set to derive trends in the UTLS at northern midlatitudes. Trends in O3 in the UT are positive and statistically significant in most

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. GEM-AQ/EC, an on-line global multi-scale chemical weather modelling system: model development and evaluation of global aerosol climatology

    Directory of Open Access Journals (Sweden)

    S. L. Gong

    2012-09-01

    Full Text Available A global air quality modeling system GEM-AQ/EC was developed by implementing tropospheric chemistry and aerosol processes on-line into the Global Environmental Multiscale weather prediction model – GEM. Due to the multi-scale features of the GEM, the integrated model, GEM-AQ/EC, is able to investigate chemical weather at scales from global to urban domains. The current chemical mechanism is comprised of 50 gas-phase species, 116 chemical and 19 photolysis reactions, and is complemented by a sectional aerosol module CAM (The Canadian Aerosol Module with 5 aerosols types: sulphate, black carbon, organic carbon, sea-salt and soil dust. Monthly emission inventories of black carbon and organic carbon from boreal and temperate vegetation fires were assembled using the most reliable areas burned datasets by countries, from statistical databases and derived from remote sensing products of 1995–2004. The model was run for ten years from from 1995–2004 with re-analyzed meteorology on a global uniform 1° × 1° horizontal resolution domain and 28 hybrid levels extending up to 10 hPa. The simulating results were compared with various observations including surface network around the globe and satellite data. Regional features of global aerosols are reasonably captured including emission, surface concentrations and aerosol optical depth. For various types of aerosols, satisfactory correlations were achieved between modeled and observed with some degree of systematic bias possibly due to large uncertainties in the emissions used in this study. A global distribution of natural aerosol contributions to the total aerosols is obtained and compared with observations.

  3. Climatology and trends of aerosol optical depth over the Mediterranean basin during the last 12years (2002-2014) based on Collection 006 MODIS-Aqua data.

    Science.gov (United States)

    Floutsi, A A; Korras-Carraca, M B; Matsoukas, C; Hatzianastassiou, N; Biskos, G

    2016-05-01

    The Mediterranean basin is a region of particular interest for studying atmospheric aerosols due to the large variety of air masses it receives, and its sensitivity to climate change. In this study we use the newest collection (C006) of aerosol optical depth from MODIS-Aqua, from which we also derived the fine-mode fraction and Ångström exponent over the last 12years (i.e., from 2002 to 2014), providing the longest analyzed dataset for this region. The long-term regional optical depth average is 0.20±0.05, with the indicated uncertainty reflecting the inter-annual variability. Overall, the aerosol optical depth exhibits a south-to-north decreasing gradient and an average decreasing trend of 0.0030 per year (19% total decrease over the study period). The correlation between the reported AOD observations with measurements from the ground AERONET stations is high (R=0.76-0.80 depending on the wavelength), with the MODIS-Aqua data being slightly overestimated. Both fine-fraction and Ångström exponent data highlight the dominance of anthropogenic aerosols over the northern, and of desert aerosols over the southern part of the region. Clear intrusions of desert dust over the Eastern Mediterranean are observed principally in spring, and in some cases in winter. Dust intrusions dominate the Western Mediterranean in the summer (and sometimes in autumn), whereas anthropogenic aerosols dominate the sub-region of the Black Sea in all seasons but especially during summer. Fine-mode optical depth is found to decrease over almost all areas of the study region during the 12-year period, marking the decreasing contribution of anthropogenic particulate matter emissions over the study area. Coarse-mode aerosol load also exhibits an overall decreasing trend. However, its decrease is smaller than that of fine aerosols and not as uniformly distributed, underlining that the overall decrease in the region arises mainly from reduced anthropogenic emissions. Copyright © 2016 Elsevier

  4. 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

  5. Study of MPLNET-Derived Aerosol Climatology over Kanpur, India, and Validation of CALIPSO Level 2 Version 3 Backscatter and Extinction Products

    Science.gov (United States)

    Misra, Amit; Tripathi, S. N.; Kaul, D. S.; Welton, Ellsworth J.

    2012-01-01

    The level 2 aerosol backscatter and extinction profiles from the NASA Micropulse Lidar Network (MPLNET) at Kanpur, India, have been studied from May 2009 to September 2010. Monthly averaged extinction profiles from MPLNET shows high extinction values near the surface during October March. Higher extinction values at altitudes of 24 km are observed from April to June, a period marked by frequent dust episodes. Version 3 level 2 Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) aerosol profile products have been compared with corresponding data from MPLNET over Kanpur for the above-mentioned period. Out of the available backscatter profiles, the16 profiles used in this study have time differences less than 3 h and distances less than 130 km. Among these profiles, four cases show good comparison above 400 m with R2 greater than 0.7. Comparison with AERONET data shows that the aerosol type is properly identified by the CALIOP algorithm. Cloud contamination is a possible source of error in the remaining cases of poor comparison. Another source of error is the improper backscatter-to-extinction ratio, which further affects the accuracy of extinction coefficient retrieval.

  6. Assessment of 1D and 3D model simulated radiation flux based on surface measurements and estimation of aerosol forcing and their climatological aspects

    Science.gov (United States)

    Subba, T.; Gogoi, M. M.; Pathak, B.; Ajay, P.; Bhuyan, P. K.; Solmon, F.

    2018-05-01

    Ground reaching solar radiation flux was simulated using a 1-dimensional radiative transfer (SBDART) and a 3-dimensional regional climate (RegCM 4.4) model and their seasonality against simultaneous surface measurements carried out using a CNR4 net Radiometer over a sub-Himalayan foothill site of south-east Asia was assessed for the period from March 2013-January 2015. The model simulated incoming fluxes showed a very good correlation with the measured values with correlation coefficient R2 0.97. The mean bias errors between these two varied from -40 W m-2 to +7 W m-2 with an overestimation of 2-3% by SBDART and an underestimation of 2-9% by RegCM. Collocated measurements of the optical parameters of aerosols indicated a reduction in atmospheric transmission path by 20% due to aerosol load in the atmosphere when compared with the aerosol free atmospheric condition. Estimation of aerosol radiative forcing efficiency (ARFE) indicated that the presence of black carbon (BC, 10-15%) led to a surface dimming by -26.14 W m-2 τ-1 and a potential atmospheric forcing of +43.04 W m-2 τ-1. BC alone is responsible for >70% influence with a major role in building up of forcing efficiency of +55.69 W m-2 τ-1 (composite) in the atmosphere. On the other hand, the scattering due to aerosols enhance the outgoing radiation at the top of the atmosphere (ARFETOA -12.60 W m-2 ω-1), the absence of which would have resulted in ARFETOA of +16.91 W m-2 τ-1 (due to BC alone). As a result, 3/4 of the radiation absorption in the atmosphere is ascribed to the presence of BC. This translated to an atmospheric heating rate of 1.0 K day-1, with 0.3 K day-1 heating over the elevated regions (2-4 km) of the atmosphere, especially during pre-monsoon season. Comparison of the satellite (MODIS) derived and ground based estimates of surface albedo showed seasonal difference in their magnitudes (R2 0.98 during retreating monsoon and winter; 0.65 during pre-monsoon and monsoon), indicating that the

  7. 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

  8. 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.

  9. 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)

  10. 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)

  11. Climatology 2011: An MLS and Sonde Derived Ozone Climatology for Satellite Retrieval Algorithms

    Science.gov (United States)

    McPeters, Richard D.; Labow, Gordon J.

    2012-01-01

    The ozone climatology used as the a priori for the version 8 Solar Backscatter Ultraviolet (SBUV) retrieval algorithms has been updated. The Microwave Limb Sounder (MLS) instrument on Aura has excellent latitude coverage and measures ozone daily from the upper troposphere to the lower mesosphere. The new climatology consists of monthly average ozone profiles for ten degree latitude zones covering pressure altitudes from 0 to 65 km. The climatology was formed by combining data from Aura MLS (2004-2010) with data from balloon sondes (1988-2010). Ozone below 8 km (below 12 km at high latitudes) is based on balloons sondes, while ozone above 16 km (21 km at high latitudes) is based on MLS measurements. Sonde and MLS data are blended in the transition region. Ozone accuracy in the upper troposphere is greatly improved because of the near uniform coverage by Aura MLS, while the addition of a large number of balloon sonde measurements improves the accuracy in the lower troposphere, in the tropics and southern hemisphere in particular. The addition of MLS data also improves the accuracy of climatology in the upper stratosphere and lower mesosphere. The revised climatology has been used for the latest reprocessing of SBUV and TOMS satellite ozone data.

  12. 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...

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Preliminary Monthly Climatological Summaries

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary Local Climatological Data, recorded since 1970 on Weather Burean Form 1030 and then National Weather Service Form F-6. The preliminary climate data pages...

  2. Reference Climatological Stations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Reference Climatological Stations (RCS) network represents the first effort by NOAA to create and maintain a nationwide network of stations located only in areas...

  3. OW Levitus Climatology

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The dataset consists of global temperature and salinity climatologies with a spatial resolution of 1x1 degree, and consists of 19 levels (surface - 5000m). It was...

  4. Climatological Data National Summary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The CDNS was published from 1950 - 1980. Monthly and annual editions contain summarized climatological information from the following publications: Local...

  5. Historical Climatology Series

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Historical Climatology Series (HCS) is a set of climate-related publications published by NOAA's National Climatic Data Center beginning in 1978. HCS is...

  6. 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.

  7. 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.

  8. Hydro-climatology

    DEFF Research Database (Denmark)

    The hydro-climatological approach of this volume illustrates the scientific and practical value of considering hydrological phenomena and processes in a climate context to improve understanding of controls, process interaction, and past and future variability/change. Contributions deal with under......The hydro-climatological approach of this volume illustrates the scientific and practical value of considering hydrological phenomena and processes in a climate context to improve understanding of controls, process interaction, and past and future variability/change. Contributions deal...... considered. The interdisciplinary approach reveals information and perspective that go beyond the study of cli ate and hydro gy alone...

  9. 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.

  10. 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.

  11. Teaching Climatology and Meterology

    OpenAIRE

    Waddington, Shelagh B.

    1997-01-01

    Climatology and meteorology are often regarded as very difficult to teach by teachers and very hard to learn by students. This paper presents simple practical exercises which will enable teachers to make the topic of greater interest and easier for students to understand some of the basic ideas.

  12. A comprehensive overview of the climatological composition of the Asian summer monsoon anticyclone based on 10 years of Aura Microwave Limb Sounder measurements

    Science.gov (United States)

    Santee, M. L.; Manney, G. L.; Livesey, N. J.; Schwartz, M. J.; Neu, J. L.; Read, W. G.

    2017-05-01

    Intense deep convection associated with the Asian summer monsoon (ASM) lofts surface pollutants to the upper troposphere/lower stratosphere (UTLS), where strong winds and long chemical lifetimes allow intercontinental transport, affecting atmospheric composition around the globe. The Aura Microwave Limb Sounder (MLS), launched in 2004, makes simultaneous colocated measurements of trace gases and cloud ice water content (a proxy for deep convection) in the UTLS on a daily basis. Here we exploit the dense spatial and temporal coverage, long-term data record, extensive measurement suite, and insensitivity to aerosol and most clouds of Aura MLS to characterize the climatological (2005-2014) composition of the ASM anticyclone throughout its annual life cycle. We use version 4 MLS data to quantify spatial and temporal variations in both tropospheric (H2O, CO, CH3Cl, CH3CN, CH3OH) and stratospheric (O3, HNO3, HCl) tracers on four potential temperature surfaces (350-410 K). Inside the mature anticyclone, all species exhibit substantial changes, not only from their premonsoon distributions in the ASM region but also from their summertime distributions in the rest of the hemisphere. Different tracers exhibit dissimilar seasonal evolution, and the exact location and timing of their extreme values vary. Although individual aspects of the anticyclone have been described previously, we present a uniquely comprehensive overview of the climatological seasonal evolution of the ASM and its impact on UTLS composition. This work provides valuable context for planned in situ measurements as well as a benchmark for model evaluation and future investigations of interannual variability and long-term changes in monsoon processes.

  13. 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

  14. 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.

  15. 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...

  16. Situational Lightning Climatologies

    Science.gov (United States)

    Bauman, William; Crawford, Winifred

    2010-01-01

    Research has revealed distinct spatial and temporal distributions of lightning occurrence that are strongly influenced by large-scale atmospheric flow regimes. It was believed there were two flow systems, but it has been discovered that actually there are seven distinct flow regimes. The Applied Meteorology Unit (AMU) has recalculated the lightning climatologies for the Shuttle Landing Facility (SLF), and the eight airfields in the National Weather Service in Melbourne (NWS MLB) County Warning Area (CWA) using individual lightning strike data to improve the accuracy of the climatologies. The software determines the location of each CG lightning strike with 5-, 10-, 20-, and 30-nmi (.9.3-, 18.5-, 37-, 55.6-km) radii from each airfield. Each CG lightning strike is binned at 1-, 3-, and 6-hour intervals at each specified radius. The software merges the CG lightning strike time intervals and distance with each wind flow regime and creates probability statistics for each time interval, radii, and flow regime, and stratifies them by month and warm season. The AMU also updated the graphical user interface (GUI) with the new data.

  17. On Diffusive Climatological Models.

    Science.gov (United States)

    Griffel, D. H.; Drazin, P. G.

    1981-11-01

    A simple, zonally and annually averaged, energy-balance climatological model with diffusive heat transport and nonlinear albedo feedback is solved numerically. Some parameters of the model are varied, one by one, to find the resultant effects on the steady solution representing the climate. In particular, the outward radiation flux, the insulation distribution and the albedo parameterization are varied. We have found an accurate yet simple analytic expression for the mean annual insolation as a function of latitude and the obliquity of the Earth's rotation axis; this has enabled us to consider the effects of the oscillation of the obliquity. We have used a continuous albedo function which fits the observed values; it considerably reduces the sensitivity of the model. Climatic cycles, calculated by solving the time-dependent equation when parameters change slowly and periodically, are compared qualitatively with paleoclimatic records.

  18. Estonian total ozone climatology

    Directory of Open Access Journals (Sweden)

    K. Eerme

    Full Text Available The climatological characteristics of total ozone over Estonia based on the Total Ozone Mapping Spectrometer (TOMS data are discussed. The mean annual cycle during 1979–2000 for the site at 58.3° N and 26.5° E is compiled. The available ground-level data interpolated before TOMS, have been used for trend detection. During the last two decades, the quasi-biennial oscillation (QBO corrected systematic decrease of total ozone from February–April was 3 ± 2.6% per decade. Before 1980, a spring decrease was not detectable. No decreasing trend was found in either the late autumn ozone minimum or in the summer total ozone. The QBO related signal in the spring total ozone has an amplitude of ± 20 DU and phase lag of 20 months. Between 1987–1992, the lagged covariance between the Singapore wind and the studied total ozone was weak. The spring (April–May and summer (June–August total ozone have the best correlation (coefficient 0.7 in the yearly cycle. The correlation between the May and August total ozone is higher than the one between the other summer months. Seasonal power spectra of the total ozone variance show preferred periods with an over 95% significance level. Since 1986, during the winter/spring, the contribution period of 32 days prevails instead of the earlier dominating 26 days. The spectral densities of the periods from 4 days to 2 weeks exhibit high interannual variability.

    Key words. Atmospheric composition and structure (middle atmosphere – composition and chemistry; volcanic effects – Meteorology and atmospheric dynamics (climatology

  19. A Model of the Effect of Ozone Depletion on Lower-Stratospheric Structure

    Science.gov (United States)

    Olsen, Mark A.; Stolarski, Richard S.; Gupta, Mohan L.; Nielsen, J. Eric; Pawson, Steven

    2005-01-01

    We have run two twenty-year integrations of a global circulation model using 1978-1980 and 1998-2000 monthly mean ozone climatologies. The ozone climatology is used solely in the radiation scheme of the model. Several key differences between the model runs will be presented. The temperature and potential vorticity (PV) structure of the lower stratosphere, particularly in the Southern Hemisphere, is significantly changed using the 1998-2000 ozone climatology. In the Southern Hemisphere summer, the lapse rate and PV-defined polar tropopauses are both at altitudes on the order of several hundred meters greater than the 1978-1980 climatological run. The 380 K potential temperature surf= is likewise at a greater altitude. The mass of the extratropical lowermost stratosphere (between the tropopause and 380 K surface) remains unchanged. The altitude differences are not observed in the Northern Hemisphere. The different ozone fields do not produce a significant change in the annual extratropical stratosphere-troposphere exchange of mass although slight variations in the spatial distribution of the exchange exist. We are also investigating a delay in the breakup of the Southern Hemisphere polar vortex due to the differing ozone climatologies.

  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. 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.

  2. 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

  3. 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.

  4. Advances in tourism climatology

    Energy Technology Data Exchange (ETDEWEB)

    Matzarakis, A.; Freitas, C.R. de; Scott, D. (eds.)

    2004-11-01

    This publication grew out of the Second International Workshop of the International Society of Biometeorology, Commission on Climate Tourism and Recreation (ISB-CCTR) that took place at the Orthodox Academy of Crete in Kolimbari, Greece, 8-11 June 2004. The aim of the meeting was to (a) bring together a selection of researchers and tourism experts to review the current state of knowledge of tourism and recreation climatology and (b) explore possibilities for future research and the role of the ISB-CCTR in this. A total of 40 delegates attended the June 2004 ISB-CCTR Workshop. Their fields of expertise included biometeorology, bioclimatology, thermal comfort and heat balance modelling, tourism marketing and planning, urban and landscape planning, architecture, climate change, emission reduction and climate change impact assessment. Participants came from universities and research institutions in Australia, Austria, Canada, Croatia, France, Germany, Greece, Hungary, Italy, the Netherlands, New Zealand, Portugal, Slovenia, United Kingdom and United States of America. Business conducted at the Workshop was divided between five sessions: assessment of climatic resources; climate change; health; weather, sports and risk forecasts; and behaviour and perception. However, the content of this publication is organised so that it reflects the new perspectives and methods that have evolved since the ISB-CCTR was established. (orig.)

  5. Global Synoptic Climatology Network (GSCN)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Dataset DSI-9290 is the result of a joint effort to create a Global Synoptic Climatology Network among the Meteorological Service of Canada (Downsview, Ontario and...

  6. Local Climatological Data (LCD) Publication

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Local Climatological Data (LCD) contains summaries from major airport weather stations that include a daily account of temperature extremes, degree days,...

  7. 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...

  8. 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.

  9. Comparative Climatology of Terrestrial Planets

    Science.gov (United States)

    Mackwell, Stephen J.; Simon-Miller, Amy A.; Harder, Jerald W.; Bullock, Mark A.

    to a future volume. Our authors have taken on the task to look at climate on the terrestrial planets in the broadest sense possible — by comparing the atmospheric processes at work on the four terrestrial bodies, Earth, Venus, Mars, and Titan (Titan is included because it hosts many of the common processes), and on terrestrial planets around other stars. These processes include the interactions of shortwave and thermal radiation with the atmosphere, condensation and vaporization of volatiles, atmospheric dynamics, chemistry and aerosol formation, and the role of the surface and interior in the long-term evolution of climate. Chapters herein compare the scientific questions, analysis methods, numerical models, and spacecraft remote sensing experiments of Earth and the other terrestrial planets, emphasizing the underlying commonality of physical processes. We look to the future by identifying objectives for ongoing research and new missions. Through these pages we challenge practicing planetary scientists, and most importantly new students of any age, to find pathways and synergies for advancing the field. In Part I, Foundations, we introduce the fundamental physics of climate on terrestrial planets. Starting with the best studied planet by far, Earth, the first chapters discuss what is known and what is not known about the atmospheres and climates of the terrestrial planets of the solar system and beyond. In Part II, Greenhouse Effect and Atmospheric Dynamics, we focus on the processes that govern atmospheric motion and the role that general circulation models play in our current understanding. In Part III, Clouds and Hazes, we provide an in-depth look at the many effects of clouds and aerosols on planetary climate. Although this is a vigorous area of research in the Earth sciences, and very strongly influences climate modeling, the important role that aerosols and clouds play in the climate of all planets is not yet well constrained. This section is intended to

  10. 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

    Anthropogenic greenhouse gas emissions tend to warm the global climate, calling for significant rapid emission reductions. As potential support measures various ideas for geoengineering are currently being discussed. The assessment of the possible manifold and as yet substantially unexplored repercussions of implementing geoengineering ideas to ameliorate climate change poses enormous challenges not least in the realm of aerosol-cloud-climate interactions. Sulphur aerosols cool the Earth's surface by reflecting short wave radiation. By increasing the amount of sulphur aerosols in the stratosphere, for example by sulphur dioxide injections, part of the anthropogenic climate warming might be compensated due to enhanced albedo. However, we are only at the beginning of understanding possible side effects. One such effect that such aerosol might have is the warming of the tropical tropopause and consequently the increase of the amount of stratospheric water vapour. Using the 2D AER Aerosol Model we calculated the aerosol distributions for yearly injections of 1, 2, 5 and 10 Mt sulphur into the lower tropical stratosphere. The results serve as input for the 3D chemistry-climate model SOCOL, which allows calculating the aerosol effect on stratospheric temperatures and chemistry. In the injection region the continuously formed sulphuric acid condensates rapidly on sulphate aerosol, which eventually grow to such extent that they sediment down to the tropical tropopause region. The growth of the aerosol particles depends on non-linear processes: the more sulphur is emitted the faster the particles grow. As a consequence for the scenario with continuous sulphur injection of totally 10 Mt per year, only 6 Mt sulphur are in the stratosphere if equilibrium is reached. According to our model calculations this amount of sulphate aerosols leads to a net surface forcing of -3.4 W/m2, which is less then expected radiative forcing by doubling of carbon dioxide concentration. Hence

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. U.S. Local Climatological Data (LCD)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Local Climatological Data (LCD) are summaries of climatological conditions from airport and other prominent weather stations managed by NWS, FAA, and DOD. The...

  18. Net Influence of an Internally Generated Guasi-biennial Oscillation on Modelled Stratospheric Climate and Chemistry

    Science.gov (United States)

    Hurwitz, Margaret M.; Oman, Luke David; Newman, Paul A.; Song, InSun

    2013-01-01

    A Goddard Earth Observing System Chemistry- Climate Model (GEOSCCM) simulation with strong tropical non-orographic gravity wave drag (GWD) is compared to an otherwise identical simulation with near-zero tropical non-orographic GWD. The GEOSCCM generates a quasibiennial oscillation (QBO) zonal wind signal in response to a tropical peak in GWD that resembles the zonal and climatological mean precipitation field. The modelled QBO has a frequency and amplitude that closely resembles observations. As expected, the modelled QBO improves the simulation of tropical zonal winds and enhances tropical and subtropical stratospheric variability. Also, inclusion of the QBO slows the meridional overturning circulation, resulting in a generally older stratospheric mean age of air. Slowing of the overturning circulation, changes in stratospheric temperature and enhanced subtropical mixing all affect the annual mean distributions of ozone, methane and nitrous oxide. Furthermore, the modelled QBO enhances polar stratospheric variability in winter. Because tropical zonal winds are easterly in the simulation without a QBO, there is a relative increase in tropical zonal winds in the simulation with a QBO. Extratropical differences between the simulations with and without a QBO thus reflect the westerly shift in tropical zonal winds: a relative strengthening of the polar stratospheric jet, polar stratospheric cooling and a weak reduction in Arctic lower stratospheric ozone.

  19. Ticosonde CFH at Costa Rica: A Seasonal Climatology of Tropical UT-LS Water Vapor and Inter-Comparisons with MLS and CALIPSO

    Science.gov (United States)

    Selkirk, Henry B.; Voemel, Holger; Avery, Melody; Rosenlof, Karen; Davis, Sean; Hurst, Dale; Schoeberl, Mark; Diaz, Jorge Andres; Morris, Gary

    2014-01-01

    Balloon sonde measurements of tropical water vapor using the Cryogenic Frostpoint Hygrometer were initiated in Costa Rica in July 2005 and have continued to the present day. Over the nine years through July 2014, the Ticosonde program has launched 174 CFH payloads, representing the longest-running and most extensive single-site balloon dataset for tropical water vapor. In this presentation we present a seasonal climatology for water vapor and ozone at Costa Rica and examine the frequency of upper tropospheric supersaturation with comparisons to cloud fraction and cloud ice water content observations from the Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) on the CALIPSO mission. We then make a critical comparison of these data to water vapor measurements from the MLS instrument on board Aura in light of recently published work for other sites. Finally, we examine time series of 2-km altitude averages in the upper troposphere-lower stratosphere at Costa Rica in light of anomalies and trends seen in various large-scale indices of tropical water vapor.

  20. 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

  1. 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.

  2. Active Learning in Introductory Climatology.

    Science.gov (United States)

    Dewey, Kenneth F.; Meyer, Steven J.

    2000-01-01

    Introduces a software package available for the climatology curriculum that determines possible climatic events according to a long-term climate history. Describes the integration of the software into the curriculum and presents examples of active learning. (Contains 19 references.) (YDS)

  3. 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.

  4. 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.

  5. Classification of hemispheric monthly mean stratospheric potential vorticity fields

    Directory of Open Access Journals (Sweden)

    R. Huth

    Full Text Available Monthly mean NCEP reanalysis potential vorticity fields at the 650 K isentropic level over the Northern and Southern Hemispheres between 1979 and 1997 were studied using multivariate analysis tools. Principal component analysis in the T-mode was applied to demonstrate the validity of such statistical techniques for the study of stratospheric dynamics and climatology. The method, complementarily applied to both the raw and anomaly fields, was useful in determining and classifying the characteristics of winter and summer PV fields on both hemispheres, in particular, the well-known differences in the behaviour and persistence of the polar vortices. It was possible to identify such features as sudden warming events in the Northern Hemisphere and final warming dates in both hemispheres. The stratospheric impact of other atmospheric processes, such as volcanic eruptions, also identified though the results, must be viewed at this stage as tentative. An interesting change in behaviour around 1990 was detected over both hemispheres.

    Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; general circulation; climatology

  6. An A-Train Climatology of Extratropical Cyclone Clouds

    Science.gov (United States)

    Posselt, Derek J.; van den Heever, Susan C.; Booth, James F.; Del Genio, Anthony D.; Kahn, Brian; Bauer, Mike

    2016-01-01

    Extratropical cyclones (ETCs) are the main purveyors of precipitation in the mid-latitudes, especially in winter, and have a significant radiative impact through the clouds they generate. However, general circulation models (GCMs) have trouble representing precipitation and clouds in ETCs, and this might partly explain why current GCMs disagree on to the evolution of these systems in a warming climate. Collectively, the A-train observations of MODIS, CloudSat, CALIPSO, AIRS and AMSR-E have given us a unique perspective on ETCs: over the past 10 years these observations have allowed us to construct a climatology of clouds and precipitation associated with these storms. This has proved very useful for model evaluation as well in studies aimed at improving understanding of moist processes in these dynamically active conditions. Using the A-train observational suite and an objective cyclone and front identification algorithm we have constructed cyclone centric datasets that consist of an observation-based characterization of clouds and precipitation in ETCs and their sensitivity to large scale environments. In this presentation, we will summarize the advances in our knowledge of the climatological properties of cloud and precipitation in ETCs acquired with this unique dataset. In particular, we will present what we have learned about southern ocean ETCs, for which the A-train observations have filled a gap in this data sparse region. In addition, CloudSat and CALIPSO have for the first time provided information on the vertical distribution of clouds in ETCs and across warm and cold fronts. We will also discuss how these observations have helped identify key areas for improvement in moist processes in recent GCMs. Recently, we have begun to explore the interaction between aerosol and cloud cover in ETCs using MODIS, CloudSat and CALIPSO. We will show how aerosols are climatologically distributed within northern hemisphere ETCs, and how this relates to cloud cover.

  7. 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.

  8. Ultraviolet and visible radiation at Barrow, Alaska: Climatology and influencing factors on the basis of version 2 National Science Foundation network data

    Science.gov (United States)

    Bernhard, Germar; Booth, Charles R.; Ehramjian, James C.; Stone, Robert; Dutton, Ellsworth G.

    2007-05-01

    Spectral ultraviolet (UV) and visible irradiance has been measured near Barrow, Alaska (71°N, 157°W), between 1991 and 2005 with a SUV-100 spectroradiometer. The instrument is part of the U.S. National Science Foundation's UV Monitoring Network. Here we present results based on the recently produced "version 2" data release, which supersedes published "version 0" data. Cosine error and wavelength-shift corrections applied to the new version increased biologically effective UV dose rates by 0-10%. Corrected clear-sky measurements of different years are typically consistent to within ±3%. Measurements were complemented with radiative transfer model calculations to retrieve total ozone and surface albedo from measured spectra and for the separation of the different factors influencing UV and visible radiation. A climatology of UV and visible radiation was established, focusing on annual cycles, trends, and the effect of clouds. During several episodes in spring of abnormally low total ozone, the daily UV dose at 305 nm exceeded the climatological mean by up to a factor of 2.6. Typical noontime UV Indices during summer vary between 2 and 4; the highest UV Index measured was 5.0 and occurred when surface albedo was unusually high. Radiation levels in the UV-A and visible exhibit a strong spring-autumn asymmetry. Irradiance at 345 nm peaks on approximately 20 May, 1 month before the solstice. This asymmetry is caused by increased cloudiness in autumn and high albedo in spring, when the snow covered surface enhances downwelling UV irradiance by up to 57%. Clouds reduce UV radiation at 345 nm on average by 4% in March and by more than 40% in August. Aerosols reduce UV by typically 5%, but larger reductions were observed during Arctic haze events. Stratospheric aerosols from the Pinatubo eruption in 1991 enhanced spectral irradiance at 305 nm for large solar zenith angles. The year-to-year variations of spectral irradiance at 305 nm and of the UV Index are mostly caused

  9. Satellite Detection of Orographic Gravity-wave Activity in the Winter Subtropical Stratosphere over Australia and Africa

    Science.gov (United States)

    Eckermann, S. D.; Wu, D. L.

    2012-01-01

    Orographic gravity-wave (OGW) parameterizations in models produce waves over subtropical mountain ranges in Australia and Africa that propagate into the stratosphere during austral winter and deposit momentum, affecting weather and climate. Satellite sensors have measured stratospheric GWs for over a decade, yet find no evidence of these waves. So are parameterizations failing here? Here we argue that the short wavelengths of subtropical OGWs place them near or below the detection limits of satellite sensors. To test this hypothesis, we reanalyze nine years of stratospheric radiances from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite during austral winter, applying new averaging techniques to maximize signal-to-noise and improve thresholds for OGW detection. Deep climatological enhancements in stratospheric OGW variance over specific mountain ranges in Australia and southern Africa are revealed for the first time, which exhibit temporal and vertical variations consistent with predicted OGW responses to varying background winds.

  10. Investigation of the question of a danger to the population by fallout from the stratospheric depot

    International Nuclear Information System (INIS)

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

    1975-01-01

    The self-developed evaluation programme modified for the present tasks - a programme to set up continuous isentropical trajectory analyses and to investigate the tropopause fine structure for the determination of the climatology of the intrusion of stratospheric (contaminated) air into the troposphere and its transport to a point of the earth's surface in the temperate latitudes, is fully efficient. It does not merely determine trivial cases with direct sinking from the lower stratoshere to the measuring station (pure adiabatic case), but cases of non-adiabatic mixture processes can also be described by using several trajectories corresponding with one another. The method of cross-section and longitudinal section analyses gives the data necessary for the description of the intrusion of stratospheric air through the tropopause with sufficient accuracy. Based on the knowledge obtained sofar, a scheme to predict stratospheric intrusions has been set up and experimentally applied. The very first results are already promising. (orig.) [de

  11. TRMM-Based Lightning Climatology

    Science.gov (United States)

    Cecil, Daniel J.; Buechler, Dennis E.; Blakeslee, Richard J.

    2011-01-01

    Gridded climatologies of total lightning flash rates seen by the spaceborne Optical Transient Detector (OTD) and Lightning Imaging Sensor (LIS) have been updated. OTD collected data from May 1995 to March 2000. LIS data (equatorward of about 38 deg) has been added for 1998-2010. Flash counts from each instrument are scaled by the best available estimates of detection efficiency. The long LIS record makes the merged climatology most robust in the tropics and subtropics, while the high latitude data is entirely from OTD. The mean global flash rate from the merged climatology is 46 flashes per second. The peak annual flash rate at 0.5 deg scale is 160 fl/square km/yr in eastern Congo. The peak monthly average flash rate at 2.5 scale is 18 fl/square km/mo, from early April to early May in the Brahmaputra Valley of far eastern India. Lightning decreases in this region during the monsoon season, but increases further north and west. A monthly average peak from early August to early September in northern Pakistan also exceeds any monthly averages from Africa, despite central Africa having the greatest yearly average. Most continental regions away from the equator have an annual cycle with lightning flash rates peaking in late spring or summer. The main exceptions are India and southeast Asia, with springtime peaks in April and May. For landmasses near the equator, flash rates peak near the equinoxes. For many oceanic regions, the peak flash rates occur in autumn. This is particularly noticeable for the Mediterranean and North Atlantic. Landmasses have a strong diurnal cycle of lightning, with flash rates generally peaking between 3-5 pm local solar time. The central United States flash rates peak later, in late evening or early night. Flash rates peak after midnight in northern Argentina. These regions are known for large, intense, long-lived mesoscale convective systems.

  12. Los Alamos Climatology 2016 Update

    Energy Technology Data Exchange (ETDEWEB)

    Bruggeman, David Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-10

    The Los Alamos National Laboratory (LANL or the Laboratory) operates a meteorology monitoring network to support LANL emergency response, engineering designs, environmental compliance, environmental assessments, safety evaluations, weather forecasting, environmental monitoring, research programs, and environmental restoration. Weather data has been collected in Los Alamos since 1910. Bowen (1990) provided climate statistics (temperature and precipitation) for the 1961– 1990 averaging period, and included other analyses (e.g., wind and relative humidity) based on the available station locations and time periods. This report provides an update to the 1990 publication Los Alamos Climatology (Bowen 1990).

  13. 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

  14. 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

  15. 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.

  16. Tropopause referenced ozone climatology and inter-annual variability (1994–2003 from the MOZAIC programme

    Directory of Open Access Journals (Sweden)

    Thouret

    2006-01-01

    Full Text Available The MOZAIC programme collects ozone and water vapour data using automatic equipment installed on board five long-range Airbus A340 aircraft flying regularly all over the world since August 1994. Those measurements made between September 1994 and August 1996 allowed the first accurate ozone climatology at 9–12 km altitude to be generated. The seasonal variability of the tropopause height has always provided a problem when constructing climatologies in this region. To remove any signal from the seasonal and synoptic scale variability in tropopause height we have chosen in this further study of these and subsequent data to reference our climatology to the altitude of the tropopause. We define the tropopause as a mixing zone 30 hPa thick across the 2 pvu potential vorticity surface. A new ozone climatology is now available for levels characteristic of the upper troposphere (UT and the lower stratosphere (LS regardless of the seasonal variations of the tropopause over the period 1994–2003. Moreover, this new presentation has allowed an estimation of the monthly mean climatological ozone concentration at the tropopause showing a sine seasonal variation with a maximum in May (120 ppbv and a minimum in November (65 ppbv. Besides, we present a first assessment of the inter-annual variability of ozone in this particular critical region. The overall increase in the UTLS is about 1%/yr for the 9 years sampled. However, enhanced concentrations about 10–15 % higher than the other years were recorded in 1998 and 1999 in both the UT and the LS. This so-called '1998–1999 anomaly' may be attributed to a combination of different processes involving large scale modes of atmospheric variability, circulation features and local or global pollution, but the most dominant one seems to involve the variability of the North Atlantic Oscillation (NAO as we find a strong positive correlation (above 0.60 between ozone recorded in the upper troposphere and the NAO

  17. Stable Water Isotopologues in the Stratosphere Retrieved from Odin/SMR Measurements

    Directory of Open Access Journals (Sweden)

    Tongmei Wang

    2018-01-01

    Full Text Available Stable Water Isotopologues (SWIs are important diagnostic tracers for understanding processes in the atmosphere and the global hydrological cycle. Using eight years (2002–2009 of retrievals from Odin/SMR (Sub-Millimetre Radiometer, the global climatological features of three SWIs, H216O, HDO and H218O, the isotopic composition δD and δ18O in the stratosphere are analysed for the first time. Spatially, SWIs are found to increase with altitude due to stratospheric methane oxidation. In the tropics, highly depleted SWIs in the lower stratosphere indicate the effect of dehydration when the air comes through the cold tropopause, while, at higher latitudes, more enriched SWIs in the upper stratosphere during summer are produced and transported to the other hemisphere via the Brewer–Dobson circulation. Furthermore, we found that more H216O is produced over summer Northern Hemisphere and more HDO is produced over summer Southern Hemisphere. Temporally, a tape recorder in H216O is observed in the lower tropical stratosphere, in addition to a pronounced downward propagating seasonal signal in SWIs from the upper to the lower stratosphere over the polar regions. These observed features in SWIs are further compared to SWI-enabled model outputs. This helped to identify possible causes of model deficiencies in reproducing main stratospheric features. For instance, choosing a better advection scheme and including methane oxidation process in a specific model immediately capture the main features of stratospheric water vapor. The representation of other features, such as the observed inter-hemispheric difference of isotopic component, is also discussed.

  18. 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.)

  19. The NEWS Water Cycle Climatology

    Science.gov (United States)

    Rodell, M.; Beaudoing, H. K.; L'Ecuyer, T.; Olson, W. S.

    2012-12-01

    NASA's Energy and Water Cycle Study (NEWS) program fosters collaborative research towards improved quantification and prediction of water and energy cycle consequences of climate change. In order to measure change, it is first necessary to describe current conditions. The goal of the first phase of the NEWS Water and Energy Cycle Climatology project was to develop "state of the global water cycle" and "state of the global energy cycle" assessments based on data from modern ground and space based observing systems and data integrating models. The project was a multi-institutional collaboration with more than 20 active contributors. This presentation will describe the results of the water cycle component of the first phase of the project, which include seasonal (monthly) climatologies of water fluxes over land, ocean, and atmosphere at continental and ocean basin scales. The requirement of closure of the water budget (i.e., mass conservation) at various scales was exploited to constrain the flux estimates via an optimization approach that will also be described. Further, error assessments were included with the input datasets, and we examine these in relation to inferred uncertainty in the optimized flux estimates in order to gauge our current ability to close the water budget within an expected uncertainty range.

  20. The NEWS Water Cycle Climatology

    Science.gov (United States)

    Rodell, Matthew; Beaudoing, Hiroko Kato; L'Ecuyer, Tristan; William, Olson

    2012-01-01

    NASA's Energy and Water Cycle Study (NEWS) program fosters collaborative research towards improved quantification and prediction of water and energy cycle consequences of climate change. In order to measure change, it is first necessary to describe current conditions. The goal of the first phase of the NEWS Water and Energy Cycle Climatology project was to develop "state of the global water cycle" and "state of the global energy cycle" assessments based on data from modern ground and space based observing systems and data integrating models. The project was a multi-institutional collaboration with more than 20 active contributors. This presentation will describe the results of the water cycle component of the first phase of the project, which include seasonal (monthly) climatologies of water fluxes over land, ocean, and atmosphere at continental and ocean basin scales. The requirement of closure of the water budget (i.e., mass conservation) at various scales was exploited to constrain the flux estimates via an optimization approach that will also be described. Further, error assessments were included with the input datasets, and we examine these in relation to inferred uncertainty in the optimized flux estimates in order to gauge our current ability to close the water budget within an expected uncertainty range.

  1. 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.

  2. Synergetic use of Aerosol Robotic Network (AERONET) and Moderate Image Spectrometer (MODIS)

    Science.gov (United States)

    Kaufman, Y.

    2004-01-01

    I shall describe several distinct modes in which AERONET data are used in conjunction with MODIS data to evaluate the global aerosol system and its impact on climate. These includes: 1) Evaluation of the aerosol diurnal cycle not available from MODIS, and the relationship between the aerosol properties derived from MODIS and the daily average of these properties; 2) Climatology of the aerosol size distribution and single scattering albedo. The climatology is used to formulate the assumptions used in the MODIS look up tables used in the inversion of MODIS data; 3) Measurement of the aerosol effect on irradiation of the surface, this is used in conjunction with the MODIS evaluation of the aerosol effect at the TOA; and 4) Assessment of the aerosol baseline on top off which the satellite data are used to find the amount of dust or anthropogenic aerosol.

  3. Impact of chemical lateral boundary conditions in a regional air quality forecast model on surface ozone predictions during stratospheric intrusions

    Science.gov (United States)

    Pendlebury, Diane; Gravel, Sylvie; Moran, Michael D.; Lupu, Alexandru

    2018-02-01

    A regional air quality forecast model, GEM-MACH, is used to examine the conditions under which a limited-area air quality model can accurately forecast near-surface ozone concentrations during stratospheric intrusions. Periods in 2010 and 2014 with known stratospheric intrusions over North America were modelled using four different ozone lateral boundary conditions obtained from a seasonal climatology, a dynamically-interpolated monthly climatology, global air quality forecasts, and global air quality reanalyses. It is shown that the mean bias and correlation in surface ozone over the course of a season can be improved by using time-varying ozone lateral boundary conditions, particularly through the correct assignment of stratospheric vs. tropospheric ozone along the western lateral boundary (for North America). Part of the improvement in surface ozone forecasts results from improvements in the characterization of near-surface ozone along the lateral boundaries that then directly impact surface locations near the boundaries. However, there is an additional benefit from the correct characterization of the location of the tropopause along the western lateral boundary such that the model can correctly simulate stratospheric intrusions and their associated exchange of ozone from stratosphere to troposphere. Over a three-month period in spring 2010, the mean bias was seen to improve by as much as 5 ppbv and the correlation by 0.1 depending on location, and on the form of the chemical lateral boundary condition.

  4. Evaluation of linear ozone photochemistry parametrizations in a stratosphere-troposphere data assimilation system

    Directory of Open Access Journals (Sweden)

    A. J. Geer

    2007-01-01

    Full Text Available This paper evaluates the performance of various linear ozone photochemistry parametrizations using the stratosphere-troposphere data assimilation system of the Met Office. A set of experiments were run for the period 23 September 2003 to 5 November 2003 using the Cariolle (v1.0 and v2.1, LINOZ and Chem2D-OPP (v0.1 and v2.1 parametrizations. All operational meteorological observations were assimilated, together with ozone retrievals from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS. Experiments were validated against independent data from the Halogen Occultation Experiment (HALOE and ozonesondes. Additionally, a simple offline method for comparing the parametrizations is introduced. It is shown that in the upper stratosphere and mesosphere, outside the polar night, ozone analyses are controlled by the photochemistry parametrizations and not by the assimilated observations. The most important factor in getting good results at these levels is to pay attention to the ozone and temperature climatologies in the parametrizations. There should be no discrepancies between the climatologies and the assimilated observations or the model, but there is also a competing demand that the climatologies be objectively accurate in themselves. Conversely, in the lower stratosphere outside regions of heterogeneous ozone depletion, the ozone analyses are dominated by observational increments and the photochemistry parametrizations have little influence. We investigate a number of known problems in LINOZ and Cariolle v1.0 in more detail than previously, and we find discrepancies in Cariolle v2.1 and Chem2D-OPP v2.1, which are demonstrated to have been removed in the latest available versions (v2.8 and v2.6 respectively. In general, however, all the parametrizations work well through much of the stratosphere, helped by the presence of good quality assimilated MIPAS observations.

  5. Climatological features of blocking anticyclones

    International Nuclear Information System (INIS)

    Lupo, A.R.; Smith, P.J.; Oglesby, R.J.

    1994-01-01

    Several climatological studies have been previously performed using large observational data sets (i.e., 10 years or longer) in order to determine the predominant characteristics of blocking anticyclones, including favored development regions, duration, preferred seasonal occurrence, and frequency of occurrence. These studies have shown that blocking anticyclones occur most frequently from October to April over the eastern Atlantic and Pacific oceans downstream from both the North American and Asian continental regions and the storm track regions to the east of these continents. Some studies have also revealed the presence of a third region block formation in western Russia near 40 degrees E which is associated with another storm track region over the Mediterranean and western Asia

  6. 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.

  7. Ability of the CCSR-NIES atmospheric general circulation model in the stratosphere. Chapter 3

    International Nuclear Information System (INIS)

    Sugata, S.

    1997-01-01

    A quantitative evaluation of climate change such as global warming is impossible without a high-quality numerical model which describes the dynamics of the climate system and the circulation of energy and materials. The Center for Climate Research - National Institute for Environmental Studies (CCSR-NIES) atmospheric general circulation model (hereafter, GCM for a general circulation model) has been developed to obtain such a high-quality model. The emphasis of the development has been laid on the troposphere and the lower stratosphere below about 30 km altitude. This is natural because human beings live on the Earth's surface and the condition of the lower atmosphere directly affects human life. However, the stratosphere and the upper atmosphere beyond it have recently been the focus even in investigations of climate change, because they are relevant to many issues which relate closely to tropospheric climate change, such as the ozone hole, material exchange between the stratosphere and the troposphere, and physical interaction between the stratosphere and troposphere. This study extended the region of the CCSR-NIES GCM to the lower mesosphere (about 70 km from the surface). This is our first attempt to investigate this GCM's climatology in the upper atmosphere, although some studies for QBO in the middle and lower stratosphere had been done with the GCM

  8. 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

  9. 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

  10. 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

  11. 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

  12. Introduction to Global Urban Climatology

    Science.gov (United States)

    Varquez, A. C. G.; Kanda, M.; Kawano, N.; Darmanto, N. S.; Dong, Y.

    2016-12-01

    Urban heat island (UHI) is a widely investigated phenomenon in the field of urban climate characterized by the warming of urban areas relative to its surrounding rural environs. Being able to understand the mechanism behind the UHI formation of a city and distinguish its impact from that of global climate change is indispensable when identifying adaptation and mitigation strategies. However, the lack of UHI studies many cities especially for developing countries makes it difficult to generalize the mechanism for UHI formation. Thus, there is an impending demand for studies that focus on the simultaneous analyses of UHI and its trends throughout the world. Hence, we propose a subfield of urban climatology, called "global urban climatology" (GUC), which mainly focuses on the uniform understanding of urban climates across all cities, globally. By using globally applicable methodologies to quantify and compare urban heat islands of cities with diverse backgrounds, including their geography, climate, socio-demography, and other factors, a universal understanding of the mechanisms underlying the formation of the phenomenon can be established. The implementation of GUC involves the use of globally acquired historical observation networks, gridded meteorological parameters from climate models, global geographic information system datasets; the construction of a distributed urban parameter database; and the development of techniques necessary to model the urban climate. Research under GUC can be categorized into three approaches. The collaborative approach (1st) relies on the collection of data from micro-scale experiments conducted worldwide with the aid or development of professional social networking platforms; the analytical approach (2nd) relies on the use of global weather station datasets and their corresponding objectively analysed global outputs; and the numerical approach (3rd) relies on the global estimation of high-resolution urban-representative parameters as

  13. Ozone climatology over western Mediterranean Sea

    International Nuclear Information System (INIS)

    Pibiri, G.; Randaccio, P.; Serra, A.; Sollai, A.

    1984-01-01

    A preliminary climatology of atmospheric ozone over Western Mediterranean Sea is given by analysis of the upper observations of O 3 carried out at Cagliari-Elmas station from 1968 to 1976. Some peculiarities are here illustrated and discussed

  14. Global Daily Climatology Network: Kazakhstan subset

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a compilation of in situ daily meteorological observations for Kazakhstan within the framework of joint efforts to create Global Daily Climatology...

  15. Northeast Pacific Regional Climatology (NCEI Accession 0163799)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Northeast Pacific (NEP) new regional climatology is derived from the NCEI World Ocean Database archive of temperature and salinity and covers a time period from...

  16. Northwest Atlantic Regional Climatology (NCEI Accession 0155889)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To provide an improved oceanographic foundation and reference for multi-disciplinary studies of the Northwest Atlantic Ocean, NCEI Regional Climatology Team...

  17. U.S. Annual Climatological Summaries

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Annual Climatological Summary contains historical monthly and annual summaries for over 8000 U.S. locations. Observing stations are located in the United States of...

  18. Quality Controlled Local Climatological Data (QCLCD) Publication

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Quality Controlled Local Climatological Data (QCLCD) contains summaries from major airport weather stations that include a daily account of temperature extremes,...

  19. Climatology of the Savannah River Plant site

    International Nuclear Information System (INIS)

    Hoel, D.D.

    1984-06-01

    This document contains information on the climatological characteristics of the SRP site, as well as information on relative concentrations and deposition for specific radionuclides. 42 references, 42 figures, 45 tables

  20. Borneo Vortices: A case study and its relation to climatology

    Science.gov (United States)

    Braesicke, P.; Ooi, S. H.; Samah, A. A.

    2012-04-01

    Borneo vortices (BVs) develop over the South China Sea and are main drivers for the formation of deep convection and heavy rainfall in East Malaysia. We present a case study of a cold-surge-induced BV during January 2010 in which the export of potential energy lead to a strengthening of the subtropical jet. Potential vorticity (PV) and water vapour analyses confirm a significant impact of the BV on upper tropospheric composition. Dry, high PV air is found far below 100 hPa in the vicinty of the vortex. Using a PV threshold analysis of ERA-Interim data we construct a climatological composite of similar events and characterise the thermal, dynamical and composition structure of a 'typical' BV. We note the preferential formation of BVs during ENSO cold conditions and show that two effects contribute to the formation of the dry upper layer above a BV: Air is vertically transported upwards in the BV whilst precipitating and the large scale flow in which the BV is embedded advect dry, ozone rich air from the equatorial TTL over the BV. Thus the occurence frequency of BVs is important for the regional variability of upper tropospheric/lower stratospheric composition.

  1. Constructing Ozone Profile Climatologies with Self-Organizing Maps: Illustrations with CONUS Ozonesonde Data

    Science.gov (United States)

    Thompson, A. M.; Stauffer, R. M.; Young, G. S.

    2015-12-01

    Ozone (O3) trends analysis is typically performed with monthly or seasonal averages. Although this approach works well for stratospheric or total O3, uncertainties in tropospheric O3 amounts may be large due to rapid meteorological changes near the tropopause and in the lower free troposphere (LFT) where pollution has a days-weeks lifetime. We use self-organizing maps (SOM), a clustering technique, as an alternative for creating tropospheric climatologies from O3 soundings. In a previous study of 900 tropical ozonesondes, clusters representing >40% of profiles deviated > 1-sigma from mean O­3. Here SOM are based on 15 years of data from four sites in the contiguous US (CONUS; Boulder, CO; Huntsville, AL; Trinidad Head, CA; Wallops Island, VA). Ozone profiles from 2 - 12 km are used to evaluate the impact of tropopause variability on climatology; 2 - 6 km O3 profile segments are used for the LFT. Near-tropopause O­3 is twice the mean O­3 mixing ratio in three clusters of 2 - 12 km O3, representing > 15% of profiles at each site. Large mid and lower-tropospheric O3 deviations from monthly means are found in clusters of both 2 - 12 and 2 - 6 km O3. Positive offsets result from pollution and stratosphere-to-troposphere exchange. In the LFT the lowest tropospheric O3 is associated with subtropical air. Some clusters include profiles with common seasonality but other factors, e.g., tropopause height or LFT column amount, characterize other SOM nodes. Thus, as for tropical profiles, CONUS O­3 averages can be a poor choice for a climatology.

  2. 9+ Years of CALIOP PSC Data: An Evolving Climatology

    Science.gov (United States)

    Pitts, Michael C.; Poole, Lamont R.

    2015-01-01

    Polar stratospheric clouds (PSCs) play key roles in the springtime chemical depletion of ozone at high latitudes. PSC particles provide sites for heterogeneous chemical reactions that transform stable chlorine and bromine reservoir species into highly reactive ozone-destructive forms. Furthermore, large nitric acid trihydrate (NAT) PSC particles can irreversibly redistribute odd nitrogen through gravitational sedimentation, which prolongs the ozone depletion process by slowing the reformation of the stable chlorine reservoirs. However, there are still significant gaps in our understanding of PSC processes, particularly concerning the details of NAT particle formation. Spaceborne observations from the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) lidar on the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite are providing a rich new dataset for studying PSCs on unprecedented vortex-wide scales. In this paper, we examine the vertical and spatial distribution of PSCs in the Antarctic and Arctic on vortex-wide scales for entire PSC seasons over the more than nine-year data record.

  3. 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.

  4. 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.

  5. 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

  6. Biomes computed from simulated climatologies

    Energy Technology Data Exchange (ETDEWEB)

    Claussen, M.; Esch, M. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    1994-01-01

    The biome model of Prentice et al. is used to predict global patterns of potential natural plant formations, or biomes, from climatologies simulated by ECHAM, a model used for climate simulations at the Max-Planck-Institut fuer Meteorologie. This study undertaken in order to show the advantage of this biome model in diagnosing the performance of a climate model and assessing effects of past and future climate changes predicted by a climate model. Good overall agreement is found between global patterns of biomes computed from observed and simulated data of present climate. But there are also major discrepancies indicated by a difference in biomes in Australia, in the Kalahari Desert, and in the Middle West of North America. These discrepancies can be traced back to in simulated rainfall as well as summer or winter temperatures. Global patterns of biomes computed from an ice age simulation reveal that North America, Europe, and Siberia should have been covered largely by tundra and taiga, whereas only small differences are for the tropical rain forests. A potential northeast shift of biomes is expected from a simulation with enhanced CO{sub 2} concentration according to the IPCC Scenario A. Little change is seen in the tropical rain forest and the Sahara. Since the biome model used is not capable of predicting chances in vegetation patterns due to a rapid climate change, the latter simulation to be taken as a prediction of chances in conditions favourable for the existence of certain biomes, not as a reduction of a future distribution of biomes. 15 refs., 8 figs., 2 tabs.

  7. Biomes computed from simulated climatologies

    Energy Technology Data Exchange (ETDEWEB)

    Claussen, W.; Esch, M.

    1992-09-01

    The biome model of Prentice et al. is used to predict global patterns of potential natural plant formations, or biomes, from climatologies simulated by ECHAM, a model used for climate simulations at the Max-Planck-Institut fuer Meteorologie. This study is undertaken in order to show the advantage of this biome model in comprehensively diagnosing the performance of a climate model and assessing effects of past and future climate changes predicted by a climate model. Good overall agreement is found between global patterns of biomes computed from observed and simulated data of present climate. But there are also major discrepancies indicated by a difference in biomes in Australia, in the Kalahari Desert, and in the Middle West of North America. These discrepancies can be traced back to failures in simulated rain fall as well as summer or winter temperatures. Global patterns of biomes computed from an ice age simulation reveal that North America, Europe, and Siberia should have been covered largely by tundra and taiga, whereas only small differences are seen for the tropical rain forests. A potential North-East shift of biomes is expected from a simulation with enhanced CO{sub 2} concentration according to the IPCC Scenario A. Little change is seen in the tropical rain forest and the Sahara. Since the biome model used is not capable of predicting changes in vegetation patterns due to a rapid climate change, the latter simulation has to be taken as a prediction of changes in conditions favorable for the existence of certain biomes, not as a prediction of a future distribution of biomes. (orig.).

  8. 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.

  9. Aerosol layer height from synergistic use of VIIRS and OMPS

    Science.gov (United States)

    Lee, J.; Hsu, N. Y. C.; Sayer, A. M.; Kim, W.; Seftor, C. J.

    2017-12-01

    This study presents an Aerosol Single-scattering albedo and Height Estimation (ASHE) algorithm, which retrieves the height of UV-absorbing aerosols by synergistically using the Visible Infrared Imaging Radiometer Suite (VIIRS) and the Ozone Mapping and Profiler Suite (OMPS). ASHE provides height information over a much broader area than ground-based or spaceborne lidar measurements by benefitting from the wide swaths of the two instruments used. As determination of single-scattering albedo (SSA) of the aerosol layer is the most critical part for the performance and coverage of ASHE, here we demonstrate three different strategies to constrain the SSA. First, ASHE is able to retrieve the SSA of UV-absorbing aerosols when Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) provides vertical profiles of the aerosol layer of interest. Second, Aerosol Robotic Network (AERONET) inversions can directly constrain the SSA of the aerosol layer when collocated with VIIRS or OMPS. Last, a SSA climatology from ASHE, AERONET, or other data sources can be used for large-scale, aged aerosol events, for which climatological SSA is well-known, at the cost of a slight decrease in retrieval accuracy. The same algorithm can be applied to measurements of similar type, such as those made by the Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI), for a long-term, consistent data record.

  10. Intercomparison of stratospheric gravity wave observations with AIRS and IASI

    Directory of Open Access Journals (Sweden)

    L. Hoffmann

    2014-12-01

    Full Text Available Gravity waves are an important driver for the atmospheric circulation and have substantial impact on weather and climate. Satellite instruments offer excellent opportunities to study gravity waves on a global scale. This study focuses on observations from the Atmospheric Infrared Sounder (AIRS onboard the National Aeronautics and Space Administration Aqua satellite and the Infrared Atmospheric Sounding Interferometer (IASI onboard the European MetOp satellites. The main aim of this study is an intercomparison of stratospheric gravity wave observations of both instruments. In particular, we analyzed AIRS and IASI 4.3 μm brightness temperature measurements, which directly relate to stratospheric temperature. Three case studies showed that AIRS and IASI provide a clear and consistent picture of the temporal development of individual gravity wave events. Statistical comparisons based on a 5-year period of measurements (2008–2012 showed similar spatial and temporal patterns of gravity wave activity. However, the statistical comparisons also revealed systematic differences of variances between AIRS and IASI that we attribute to the different spatial measurement characteristics of both instruments. We also found differences between day- and nighttime data that are partly due to the local time variations of the gravity wave sources. While AIRS has been used successfully in many previous gravity wave studies, IASI data are applied here for the first time for that purpose. Our study shows that gravity wave observations from different hyperspectral infrared sounders such as AIRS and IASI can be directly related to each other, if instrument-specific characteristics such as different noise levels and spatial resolution and sampling are carefully considered. The ability to combine observations from different satellites provides an opportunity to create a long-term record, which is an exciting prospect for future climatological studies of stratospheric

  11. Stratospheric Platforms for Monitoring Purposes

    International Nuclear Information System (INIS)

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

    2010-01-01

    Stratospheric platforms are emerging systems based on challenging technology. Goal is to create a platform, payload, and mission design which is able to complement satellite services on a local scale. Applications are close to traditional satellite business in telecommunication, navigation, science, and earth observation and include for example mobile telecommunications, navigation augmentation, atmospheric research, or border control. Stratospheric platforms could potentially support monitoring activities related to safeguards, e.g. by imagery of surfaces, operational conditions of nuclear facilities, and search for undeclared nuclear activities. Stratospheric platforms are intended to be flown in an altitude band between 16 and 30 km, above 16-20 km to take advantage of usually lower winds facilitating station keeping, below 30 km to limit the challenges to achieve a reasonable payload at acceptable platform sizes. Stratospheric platforms could substitute satellites which are expensive and lack upgrade capabilities for new equipment. Furthermore they have practically an unlimited time over an area of interest. It is intended to keep the platforms operational and maintenance free on a 24/7 basis with an average deployment time of 3 years. Geostationary satellites lack resolution. Potential customers like Armed Forces, National Agencies and commercial customers have indicated interest in the use of stratospheric platforms. Governmental entities are looking for cheaper alternatives to communications and surveillance satellites and stratospheric platforms could offer the following potential advantages: Lower operational cost than satellite or UAV (Unmanned Aerial Vehicles) constellation (fleet required); Faster deployment than satellite constellation; Repositioning capability and ability to loiter as required; Persistent long-term real-time services over a fairly large regional spot; Surge capability: Able to extend capability (either monitoring or communications

  12. A global satellite assisted precipitation climatology

    Science.gov (United States)

    Funk, Christopher C.; Verdin, Andrew P.; Michaelsen, Joel C.; Pedreros, Diego; Husak, Gregory J.; Peterson, P.

    2015-01-01

    Accurate representations of mean climate conditions, especially in areas of complex terrain, are an important part of environmental monitoring systems. As high-resolution satellite monitoring information accumulates with the passage of time, it can be increasingly useful in efforts to better characterize the earth's mean climatology. Current state-of-the-science products rely on complex and sometimes unreliable relationships between elevation and station-based precipitation records, which can result in poor performance in food and water insecure regions with sparse observation networks. These vulnerable areas (like Ethiopia, Afghanistan, or Haiti) are often the critical regions for humanitarian drought monitoring. Here, we show that long period of record geo-synchronous and polar-orbiting satellite observations provide a unique new resource for producing high resolution (0.05°) global precipitation climatologies that perform reasonably well in data sparse regions. Traditionally, global climatologies have been produced by combining station observations and physiographic predictors like latitude, longitude, elevation, and slope. While such approaches can work well, especially in areas with reasonably dense observation networks, the fundamental relationship between physiographic variables and the target climate variables can often be indirect and spatially complex. Infrared and microwave satellite observations, on the other hand, directly monitor the earth's energy emissions. These emissions often correspond physically with the location and intensity of precipitation. We show that these relationships provide a good basis for building global climatologies. We also introduce a new geospatial modeling approach based on moving window regressions and inverse distance weighting interpolation. This approach combines satellite fields, gridded physiographic indicators, and in situ climate normals. The resulting global 0.05° monthly precipitation climatology, the Climate

  13. New dynamic NNORSY ozone profile climatology

    Science.gov (United States)

    Kaifel, A. K.; Felder, M.; Declercq, C.; Lambert, J.-C.

    2012-01-01

    Climatological ozone profile data are widely used as a-priori information for total ozone using DOAS type retrievals as well as for ozone profile retrieval using optimal estimation, for data assimilation or evaluation of 3-D chemistry-transport models and a lot of other applications in atmospheric sciences and remote sensing. For most applications it is important that the climatology represents not only long term mean values but also the links between ozone and dynamic input parameters. These dynamic input parameters should be easily accessible from auxiliary datasets or easily measureable, and obviously should have a high correlation with ozone. For ozone profile these parameters are mainly total ozone column and temperature profile data. This was the outcome of a user consultation carried out in the framework of developing a new, dynamic ozone profile climatology. The new ozone profile climatology is based on the Neural Network Ozone Retrieval System (NNORSY) widely used for ozone profile retrieval from UV and IR satellite sounder data. NNORSY allows implicit modelling of any non-linear correspondence between input parameters (predictors) and ozone profile target vector. This paper presents the approach, setup and validation of a new family of ozone profile climatologies with static as well as dynamic input parameters (total ozone and temperature profile). The neural network training relies on ozone profile measurement data of well known quality provided by ground based (ozonesondes) and satellite based (SAGE II, HALOE, and POAM-III) measurements over the years 1995-2007. In total, four different combinations (modes) for input parameters (date, geolocation, total ozone column and temperature profile) are available. The geophysical validation spans from pole to pole using independent ozonesonde, lidar and satellite data (ACE-FTS, AURA-MLS) for individual and time series comparisons as well as for analysing the vertical and meridian structure of different modes of

  14. 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

  15. Condition of The Stratospheric and Mesospheric Ozone Layer Over Bulgaria for the Period 1996-2012

    Science.gov (United States)

    Kaleyna, Petya; Mukhtarov, Plamen; Miloshev, Nikolay

    2014-05-01

    A detailed analysis of the variations of the stratospheric and mesospheric ozone over Bulgaria, in the period 1996-2012, is presented in the article on the basis of ground and satellite measurements of the Total Ozone Content (TOC). The move of the most important components: yearly running mean values, amplitudes and phases of the first four harmonics of the seasonal cycle. Their mean values for the period and the existing long term trends have been found. An evaluation of the general characteristics of the short term variability of the Total Ozone Content (TOC) over Bulgaria also has been made in the article. The impact of the planetary wave activity of the stratosphere on the total ozone has been studied and the climatology of the oscillation amplitudes with periods of 4, 7, 11 and 25 days has been defined.

  16. 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

  17. 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

  18. Climatological determinants of woody cover in Africa.

    Science.gov (United States)

    Good, Stephen P; Caylor, Kelly K

    2011-03-22

    Determining the factors that influence the distribution of woody vegetation cover and resolving the sensitivity of woody vegetation cover to shifts in environmental forcing are critical steps necessary to predict continental-scale responses of dryland ecosystems to climate change. We use a 6-year satellite data record of fractional woody vegetation cover and an 11-year daily precipitation record to investigate the climatological controls on woody vegetation cover across the African continent. We find that-as opposed to a relationship with only mean annual rainfall-the upper limit of fractional woody vegetation cover is strongly influenced by both the quantity and intensity of rainfall events. Using a set of statistics derived from the seasonal distribution of rainfall, we show that areas with similar seasonal rainfall totals have higher fractional woody cover if the local rainfall climatology consists of frequent, less intense precipitation events. Based on these observations, we develop a generalized response surface between rainfall climatology and maximum woody vegetation cover across the African continent. The normalized local gradient of this response surface is used as an estimator of ecosystem vegetation sensitivity to climatological variation. A comparison between predicted climate sensitivity patterns and observed shifts in both rainfall and vegetation during 2009 reveals both the importance of rainfall climatology in governing how ecosystems respond to interannual fluctuations in climate and the utility of our framework as a means to forecast continental-scale patterns of vegetation shifts in response to future climate change.

  19. 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.

  20. Geomagnetic activity forcing of the Northern Annular Mode via the stratosphere

    Directory of Open Access Journals (Sweden)

    D. R. Palamara

    2004-03-01

    Full Text Available We consider various aspects of the link between solar-modulated geomagnetic activity and the Northern Annular Mode (NAM. Our results indicate that the geomagnetic forcing of atmospheric circulation in the Northern Hemisphere is temporally and seasonally restricted, modulated by the Quasi-Biennial Oscillation (QBO, and reliant on stratosphere-troposphere coupling. When the data are restricted to January values after 1965, for years in which the January QBO is eastwards, the correlation coefficient between the geomagnetic AA index and the NAM is 0.85. These results can account for many of the enigmatic features of Northern Hemisphere circulation. Key words. Meterology and atmospheric dynamics (general circulation, climatology

  1. Impacts of Interactive Stratospheric Chemistry on Antarctic and Southern Ocean Climate Change in the Goddard Earth Observing System Version 5 (GEOS-5)

    Science.gov (United States)

    Li, Feng; Vikhliaev, Yury V.; Newman, Paul A.; Pawson, Steven; Perlwitz, Judith; Waugh, Darryn W.; Douglass, Anne R.

    2016-01-01

    Stratospheric ozone depletion plays a major role in driving climate change in the Southern Hemisphere. To date, many climate models prescribe the stratospheric ozone layer's evolution using monthly and zonally averaged ozone fields. However, the prescribed ozone underestimates Antarctic ozone depletion and lacks zonal asymmetries. In this study we investigate the impact of using interactive stratospheric chemistry instead of prescribed ozone on climate change simulations of the Antarctic and Southern Ocean. Two sets of 1960-2010 ensemble transient simulations are conducted with the coupled ocean version of the Goddard Earth Observing System Model, version 5: one with interactive stratospheric chemistry and the other with prescribed ozone derived from the same interactive simulations. The model's climatology is evaluated using observations and reanalysis. Comparison of the 1979-2010 climate trends between these two simulations reveals that interactive chemistry has important effects on climate change not only in the Antarctic stratosphere, troposphere, and surface, but also in the Southern Ocean and Antarctic sea ice. Interactive chemistry causes stronger Antarctic lower stratosphere cooling and circumpolar westerly acceleration during November-December-January. It enhances stratosphere-troposphere coupling and leads to significantly larger tropospheric and surface westerly changes. The significantly stronger surface wind stress trends cause larger increases of the Southern Ocean Meridional Overturning Circulation, leading to year-round stronger ocean warming near the surface and enhanced Antarctic sea ice decrease.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Response of the dynamic and thermodynamic structure of the stratosphere to the solar cycle in the boreal winter

    Science.gov (United States)

    Shi, Chunhua; Gao, Yannan; Cai, Juan; Guo, Dong; Lu, Yan

    2018-04-01

    The response of the dynamic and thermodynamic structure of the stratosphere to the solar cycle in the boreal winter is investigated based on measurements of the solar cycle by the Spectral Irradiance Monitor onboard the SORCE satellite, monthly ERA-Interim Reanalysis data from the European Center for Medium-Range Weather Forecasts, the radiative transfer scheme of the Beijing Climate Center (BCC-RAD) and a multiple linear regression model. The results show that during periods of strong solar activity, the solar shortwave heating anomaly from the climatology in the tropical upper stratosphere triggers a local warm anomaly and strong westerly winds in mid-latitudes, which strengthens the upward propagation of planetary wave 1 but prevents that of wave 2. The enhanced westerly jet makes a slight adjustment to the propagation path of wave 1, but prevents wave 2 from propagating upward, decreases the dissipation of wave 2 in the extratropical upper stratosphere and hence weakens the Brewer-Dobson circulation. The adiabatic heating term in relation to the Brewer-Dobson circulation shows anomalous warming in the tropical lower stratosphere and anomalous cooling in the mid-latitude upper stratosphere.

  9. Hanford Site Climatological Data Summary 1999 with Historical Data

    International Nuclear Information System (INIS)

    Hoitink, Dana J; Burk, Kenneth W; Ramsdell, Jim V

    2000-01-01

    This document presents the climatological data measured at the Hanford Site for calendar year 1999. The information contained includes updated historical climatologies for temperature, precipitation, normal and extreme values of temperature and precipitation and other meteorological parameters

  10. Gulf of Mexico Regional Climatology (NCEI Accession 0123320)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Gulf of Mexico Regional Climatology is a set of objectively analyzed climatological fields of temperature, salinity, oxygen, phosphate, silicate, and nitrate at...

  11. 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.

  12. Climatological variability in regional air pollution

    International Nuclear Information System (INIS)

    Shannon, J.D.; Trexler, E.C. Jr.

    1995-01-01

    Although some air pollution modeling studies examine events that have already occurred (e.g., the Chernobyl plume) with relevant meteorological conditions largely known, most pollution modeling studies address expected or potential scenarios for the future. Future meteorological conditions, the major pollutant forcing function other than emissions, are inherently uncertain although much relevant information is contained in past observational data. For convenience in our discussions of regional pollutant variability unrelated to emission changes, we define meteorological variability as short-term (within-season) pollutant variability and climatological variability as year-to-year changes in seasonal averages and accumulations of pollutant variables. In observations and in some of our simulations the effects are confounded because for seasons of two different years both the mean and the within-season character of a pollutant variable may change. Effects of climatological and meteorological variability on means and distributions of air pollution parameters, particularly those related to regional visibility, are illustrated. Over periods of up to a decade climatological variability may mask or overstate improvements resulting from emission controls. The importance of including climatological uncertainties in assessing potential policies, particularly when based partly on calculated source-receptor relationships, is highlighted

  13. 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

  14. A novel tropopause-related climatology of ozone profiles

    NARCIS (Netherlands)

    Sofieva, V.F.; Tamminen, J.; Kyrola, E.; Mielonen, T.; Veefkind, J.P.; Hassler, B.; Bodeker, G.E.

    2014-01-01

    A new ozone climatology, based on ozonesonde and satellite measurements, spanning the altitude region between the earth's surface and ~60 km is presented (TpO3 climatology). This climatology is novel in that the ozone profiles are categorized according to calendar month, latitude and local

  15. 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

  16. Nine-year spatial and temporal evolution of desert dust aerosols over South and East Asia as revealed by CALIOP

    NARCIS (Netherlands)

    Proestakis, Emmanouil; Amiridis, Vassilis; Marinou, Eleni; Georgoulias, Aristeidis K.; Solomos, Stavros; Kazadzis, Stelios; Chimot, J.J.; Che, Huizheng; Alexandri, Georgia; Binietoglou, Ioannis; Daskalopoulou, Vasiliki; Kourtidis, Konstantinos A.; Johannes Van Der A, Ronald

    2018-01-01

    We present a 3-D climatology of the desert dust distribution over South and East Asia derived using CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) data. To distinguish desert dust from total aerosol load we apply a methodology developed in the framework of EARLINET

  17. Climatic impacts of anthropogenic aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Iversen, T. [Oslo Univ. (Norway)

    1996-03-01

    This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Anthropogenic production of aerosols is mainly connected with combustion of fossil fuel. Measured by particulate mass, the anthropogenic sulphate production is the dominating source of aerosols in the Northern Hemisphere. Particles emitted in mechanical processes, fly ash etc. are less important because of their shorter atmospheric residence time. Possible climatological effects of anthropogenic aerosols are usually classified in two groups: direct and indirect. Direct effects are alterations of the radiative heating budget due to the aerosol particles in clear air. Indirect effects involve the interaction between particles and cloud processes. A simplified one-layer radiation model gave cooling in the most polluted mid-latitude areas and heating due to soot absorption in the Arctic. This differential trend in heating rates may have significant effects on atmospheric meridional circulations, which is important for the atmosphere as a thermodynamic system. Recently the description of sulphur chemistry in the hemispheric scale dispersion model has been improved and will be used in a model for Mie scattering and absorption

  18. 9+ Years of CALIPSO PSC Observations: An Evolving Climatology

    Science.gov (United States)

    Pitts, Michael C.; Poole, Lamont R.

    2015-01-01

    Polar stratospheric clouds (PSCs) play a crucial role in the springtime chemical depletion of ozone at high latitudes. PSC particles (primarily supercooled ternary solution, or STS droplets) provide sites for heterogeneous chemical reactions that transform stable chlorine and bromine reservoir species into highly reactive ozone-destructive forms. Furthermore, large nitric acid trihydrate (NAT) PSC particles can irreversibly redistribute odd nitrogen through gravitational sedimentation (a process commonly known as denitrification), which prolongs the ozone depletion process by slowing the reformation of the stable chlorine reservoirs. Spaceborne observations from the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) lidar on the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite are providing a rich new dataset for studying PSCs. CALIPSO is an excellent platform for studying polar processes with CALIOP acquiring, on average, over 300,000 backscatter profiles daily at latitudes between 55o and 82o in both hemispheres. PSCs are detected in the CALIOP backscatter profiles using a successive horizontal averaging scheme that enables detection of strongly scattering PSCs (e.g., ice) at the finest possible spatial resolution (5 km), while enhancing the detection of very tenuous PSCs (e.g., low number density NAT) at larger spatial scales (up to 135 km). CALIOP PSCs are separated into composition classes (STS; liquid/NAT mixtures; and ice) based on the ensemble 532-nm scattering ratio (the ratio of total-to-molecular backscatter) and 532-nm particulate depolarization ratio (which is sensitive to the presence of non-spherical, i.e. NAT and ice particles). In this paper, we will provide an overview of the CALIOP PSC detection and composition classification algorithm and then examine the vertical and spatial distribution of PSCs in the Arctic and Antarctic on vortex-wide scales for entire PSC seasons over the more than nine-year data

  19. 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.

  20. Aerosol retrieval experiments in the ESA Aerosol_cci project

    Directory of Open Access Journals (Sweden)

    T. Holzer-Popp

    2013-08-01

    Full Text Available Within the ESA Climate Change Initiative (CCI project Aerosol_cci (2010–2013, algorithms for the production of long-term total column aerosol optical depth (AOD datasets from European Earth Observation sensors are developed. Starting with eight existing pre-cursor algorithms three analysis steps are conducted to improve and qualify the algorithms: (1 a series of experiments applied to one month of global data to understand several major sensitivities to assumptions needed due to the ill-posed nature of the underlying inversion problem, (2 a round robin exercise of "best" versions of each of these algorithms (defined using the step 1 outcome applied to four months of global data to identify mature algorithms, and (3 a comprehensive validation exercise applied to one complete year of global data produced by the algorithms selected as mature based on the round robin exercise. The algorithms tested included four using AATSR, three using MERIS and one using PARASOL. This paper summarizes the first step. Three experiments were conducted to assess the potential impact of major assumptions in the various aerosol retrieval algorithms. In the first experiment a common set of four aerosol components was used to provide all algorithms with the same assumptions. The second experiment introduced an aerosol property climatology, derived from a combination of model and sun photometer observations, as a priori information in the retrievals on the occurrence of the common aerosol components. The third experiment assessed the impact of using a common nadir cloud mask for AATSR and MERIS algorithms in order to characterize the sensitivity to remaining cloud contamination in the retrievals against the baseline dataset versions. The impact of the algorithm changes was assessed for one month (September 2008 of data: qualitatively by inspection of monthly mean AOD maps and quantitatively by comparing daily gridded satellite data against daily averaged AERONET sun

  1. 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

  2. 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

  3. Regional and applied climatology-contributions

    International Nuclear Information System (INIS)

    Endlicher, W.; Gossmann, H.

    1991-01-01

    The first three articles of this book, which is dedicated to Wolfgang Weischet, are closely related to his work on unban climatology: - A comprehensive research programme on urban climatology for the example of a medium-sized Swiss town; - A wind tunnel test in preparation of a large-scale urban construction project; - Modelling of human thermal comfort in different urban environments on the basis of comprehensive data sets of geofactors. At the same time, they provide a survey of the status and methods of modern urban climate research. The second group of contributions comprises texts which discuss the effects of individual climate elements in the biosphere and pedosphere. The third group consists of two contributions on the stability of tropical environments. Both of them discuss the semiarid regions of northern Kenia. Finally, there is a group of contributions stimulated and influenced by W. Weischet's work in Latin America. (orig./KW) [de

  4. Correlation and multifractality in climatological time series

    International Nuclear Information System (INIS)

    Pedron, I T

    2010-01-01

    Climate can be described by statistical analysis of mean values of atmospheric variables over a period. It is possible to detect correlations in climatological time series and to classify its behavior. In this work the Hurst exponent, which can characterize correlation and persistence in time series, is obtained by using the Detrended Fluctuation Analysis (DFA) method. Data series of temperature, precipitation, humidity, solar radiation, wind speed, maximum squall, atmospheric pressure and randomic series are studied. Furthermore, the multifractality of such series is analyzed applying the Multifractal Detrended Fluctuation Analysis (MF-DFA) method. The results indicate presence of correlation (persistent character) in all climatological series and multifractality as well. A larger set of data, and longer, could provide better results indicating the universality of the exponents.

  5. Climatology of local flow patterns around Basel

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R.O. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Recently a method has been developed to classify local-scale flow patterns from the wind measurements at a dense network of stations. It was found that in the MISTRAL area around Basel a dozen characteristic flow patterns occur. However, as the dense network of stations ran only during one year, no reliable climatology can be inferred from these data, especially the annual cycle of the flow patterns is not well determined from a single year of observations. As there exist several routinely operated stations in and near the MISTRAL area, a method was searched to identify the local flow patterns from the observations at the few routine stations. A linear discriminant analysis turned out to be the best method. Based of data from 11 stations which were simultaneously operated during 1990-1995 a six-year climatology of the flow patterns could be obtained. (author) 1 fig., 1 tab., 3 refs.

  6. Results of large scale wind climatologically estimations

    Directory of Open Access Journals (Sweden)

    Andrea Kircsi

    2008-05-01

    Full Text Available The aim of this article is to describe theparticular field of climatology which analyzes airmovement characteristics regarding utilization of windfor energy generation. The article describes features ofwind energy potential available in Hungary compared towind conditions in other areas of the northern quartersphere in order to assist the wind energy use developmentin Hungary. Information on wind climate gives a solidbasis for financial and economic decisions ofstakeholders in the field of wind energy utilization.

  7. Climatology of the Savannah River Plant site

    International Nuclear Information System (INIS)

    Hoel, D.D.

    1983-01-01

    This document is intended as a reference for those involved in environmental research, and preparing environmental and safety analysis reports about aspects of operations of production and support facilities at the Savannah River Plant (SRP). The information in this document is drawn from appropriate references and from the extensive meteorological data base collected on SRP. This document contains information on the climatological characteristics of the SRP site, as well as information on relative concentrations and deposition for specific radionuclides

  8. Climatological determinants of woody cover in Africa

    OpenAIRE

    Good, Stephen P.; Caylor, Kelly K.

    2011-01-01

    Determining the factors that influence the distribution of woody vegetation cover and resolving the sensitivity of woody vegetation cover to shifts in environmental forcing are critical steps necessary to predict continental-scale responses of dryland ecosystems to climate change. We use a 6-year satellite data record of fractional woody vegetation cover and an 11-year daily precipitation record to investigate the climatological controls on woody vegetation cover across the African continent....

  9. 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.)

  10. 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.

  11. 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.

  12. Polar Processes in a 50-year Simulation of Stratospheric Chemistry and Transport

    Science.gov (United States)

    Kawa, S.R.; Douglass, A. R.; Patrick, L. C.; Allen, D. R.; Randall, C. E.

    2004-01-01

    The unique chemical, dynamical, and microphysical processes that occur in the winter polar lower stratosphere are expected to interact strongly with changing climate and trace gas abundances. Significant changes in ozone have been observed and prediction of future ozone and climate interactions depends on modeling these processes successfully. We have conducted an off-line model simulation of the stratosphere for trace gas conditions representative of 1975-2025 using meteorology from the NASA finite-volume general circulation model. The objective of this simulation is to examine the sensitivity of stratospheric ozone and chemical change to varying meteorology and trace gas inputs. This presentation will examine the dependence of ozone and related processes in polar regions on the climatological and trace gas changes in the model. The model past performance is base-lined against available observations, and a future ozone recovery scenario is forecast. Overall the model ozone simulation is quite realistic, but initial analysis of the detailed evolution of some observable processes suggests systematic shortcomings in our description of the polar chemical rates and/or mechanisms. Model sensitivities, strengths, and weaknesses will be discussed with implications for uncertainty and confidence in coupled climate chemistry predictions.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. A characterization of Arctic aerosols on the basis of aerosol optical depth and black carbon measurements

    Directory of Open Access Journals (Sweden)

    R. S. Stone

    2014-06-01

    Full Text Available Abstract Aerosols, transported from distant source regions, influence the Arctic surface radiation budget. When deposited on snow and ice, carbonaceous particles can reduce the surface albedo, which accelerates melting, leading to a temperature-albedo feedback that amplifies Arctic warming. Black carbon (BC, in particular, has been implicated as a major warming agent at high latitudes. BC and co-emitted aerosols in the atmosphere, however, attenuate sunlight and radiatively cool the surface. Warming by soot deposition and cooling by atmospheric aerosols are referred to as “darkening” and “dimming” effects, respectively. In this study, climatologies of spectral aerosol optical depth AOD (2001–2011 and Equivalent BC (EBC (1989–2011 from three Arctic observatories and from a number of aircraft campaigns are used to characterize Arctic aerosols. Since the 1980s, concentrations of BC in the Arctic have decreased by more than 50% at ground stations where in situ observations are made. AOD has increased slightly during the past decade, with variations attributed to changing emission inventories and source strengths of natural aerosols, including biomass smoke and volcanic aerosol, further influenced by deposition rates and airflow patterns.

  18. 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

  19. 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

  20. A climatology of visible surface reflectance spectra

    International Nuclear Information System (INIS)

    Zoogman, Peter; Liu, Xiong; Chance, Kelly; Sun, Qingsong; Schaaf, Crystal; Mahr, Tobias; Wagner, Thomas

    2016-01-01

    We present a high spectral resolution climatology of visible surface reflectance as a function of wavelength for use in satellite measurements of ozone and other atmospheric species. The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is planned to measure backscattered solar radiation in the 290–740 nm range, including the ultraviolet and visible Chappuis ozone bands. Observation in the weak Chappuis band takes advantage of the relative transparency of the atmosphere in the visible to achieve sensitivity to near-surface ozone. However, due to the weakness of the ozone absorption features this measurement is more sensitive to errors in visible surface reflectance, which is highly variable. We utilize reflectance measurements of individual plant, man-made, and other surface types to calculate the primary modes of variability of visible surface reflectance at a high spectral resolution, comparable to that of TEMPO (0.6 nm). Using the Moderate-resolution Imaging Spectroradiometer (MODIS) Bidirection Reflectance Distribution Function (BRDF)/albedo product and our derived primary modes we construct a high spatial resolution climatology of wavelength-dependent surface reflectance over all viewing scenes and geometries. The Global Ozone Monitoring Experiment–2 (GOME-2) Lambertian Equivalent Reflectance (LER) product provides complementary information over water and snow scenes. Preliminary results using this approach in multispectral ultraviolet+visible ozone retrievals from the GOME-2 instrument show significant improvement to the fitting residuals over vegetated scenes. - Highlights: • Our goals was visible surface reflectance for satellite trace gas measurements. • Captured the range of surface reflectance spectra through EOF analysis. • Used satellite surface reflectance products for each given scene to anchor EOFs. • Generated a climatology of time/geometry dependent surface reflectance spectra. • Demonstrated potential to

  1. 16-year Climatology of Cirrus cloud properties using ground-based Lidar over Gadanki (13.45˚N, 79.18˚E)

    Science.gov (United States)

    Pandit, Amit Kumar; Raghunath, Karnam; Jayaraman, Achuthan; Venkat Ratnam, Madineni; Gadhavi, Harish

    Cirrus clouds are ubiquitous high level cold clouds predominantly consisting of ice-crystals. With their highest coverage over the tropics, these are one of the most vital and complex components of Tropical Tropopause Layer (TTL) due to their strong radiative feedback and dehydration in upper troposphere and lower stratosphere (UTLS) regions. The continuous changes in their coverage, position, thickness, and ice-crystal size and shape distributions bring uncertainties in the estimates of cirrus cloud radiative forcing. Long-term changes in the distribution of aerosols and water vapour in the TTL can influence cirrus properties. This necessitates long-term studies of tropical cirrus clouds, which are only few. The present study provides 16-year climatology of physical and optical properties of cirrus clouds observed using a ground-based Lidar located at Gadanki (13.45(°) N, 79.18(°) ˚E and 375 m amsl) in south-India. In general, cirrus clouds occurred for about 44% of the total Lidar observation time. Owing to the increased convective activities, the occurrence of cirrus clouds during the southwest-monsoon season is highest while it is lowest during the winter. Altitude distribution of cirrus clouds reveals that the peak occurrence was about 25% at 14.5 km. The most probable base and top height of cirrus clouds are 14 and 15.5 km, respectively. This is also reflected in the bulk extinction coefficient profile (at 532 nm) of cirrus clouds. These results are compared with the CALIPSO observations. Most of the time cirrus clouds are located within the TTL bounded by convective outflow level and cold-point tropopause. Cirrus clouds are thick during the monsoon season as compared to that during winter. An inverse relation between the thickness of cirrus clouds and TTL thickness is found. The occurrence of cirrus clouds at an altitude close to the tropopause (16 km) showed an increase of 8.4% in the last 16 years. Base and top heights of cirrus clouds also showed

  2. 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.

  3. 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.

  4. The effects of the Indo-Pacific warm pool on the stratosphere

    Science.gov (United States)

    Zhou, Xin; Li, Jianping; Xie, Fei; Ding, Ruiqiang; Li, Yanjie; Zhao, Sen; Zhang, Jiankai; Li, Yang

    2017-03-01

    Sea surface temperature (SST) in the Indo-Pacific warm pool (IPWP) plays a key role in influencing East Asian climate, and even affects global-scale climate change. This study defines IPWP Niño and IPWP Niña events to represent the warm and cold phases of IPWP SST anomalies, respectively, and investigates the effects of these events on stratospheric circulation and temperature. Results from simulations forced by observed SST anomalies during IPWP Niño and Niña events show that the tropical lower stratosphere tends to cool during IPWP Niño events and warm during IPWP Niña events. The responses of the northern and southern polar vortices to IPWP Niño events are fairly symmetric, as both vortices are significantly warmed and weakened. However, the responses of the two polar vortices to IPWP Niña events are of opposite sign: the northern polar vortex is warmed and weakened, but the southern polar vortex is cooled and strengthened. These features are further confirmed by composite analysis using reanalysis data. A possible dynamical mechanism connecting IPWP SST to the stratosphere is suggested, in which IPWP Niño and Niña events excite teleconnections, one similar to the Pacific-North America pattern in the Northern Hemisphere and a Rossby wave train in the Southern Hemisphere, which project onto the climatological wave in the mid-high latitudes, intensifying the upward propagation of planetary waves into the stratosphere and, in turn, affecting the polar vortex.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Up-to-date probabilistic temperature climatologies

    International Nuclear Information System (INIS)

    Krakauer, Nir Y; Devineni, Naresh

    2015-01-01

    With ongoing global warming, climatologies based on average past temperatures are increasingly recognized as imperfect guides for current conditions, yet there is no consensus on alternatives. Here, we compare several approaches to deriving updated expected values of monthly mean temperatures, including moving average, exponentially weighted moving average, and piecewise linear regression. We go beyond most previous work by presenting updated climate normals as probability distributions rather than only point estimates, enabling estimation of the changing likelihood of hot and cold extremes. We show that there is a trade-off between bias and variance in these approaches, but that bias can be mitigated by an additive correction based on a global average temperature series, which has much less interannual variability than a single-station series. Using thousands of monthly temperature time series from the Global Historical Climatology Network (GHCN), we find that the exponentially weighted moving average with a timescale of 15 years and global bias correction has good overall performance in hindcasting temperatures over the last 30 years (1984–2013) compared with the other methods tested. Our results suggest that over the last 30 years, the likelihood of extremely hot months (above the 99th percentile of the temperature probability distribution as of the early 1980s) has increased more than fourfold across the GHCN stations, whereas the likelihood of very cold months (under the 1st percentile) has decreased by over two-thirds. (letter)

  10. NASA GLDAS Evapotranspiration Data and Climatology

    Science.gov (United States)

    Rui, Hualan; Beaudoing, Hiroko Kato; Teng, William L.; Vollmer, Bruce; Rodell, Matthew

    2012-01-01

    Evapotranspiration (ET) is the water lost to the atmosphere by evaporation and transpiration. ET is a shared component in the energy and water budget, therefore, a critical variable for global energy and water cycle and climate change studies. However, direct ET measurements and data acquisition are difficult and expensive, especially at the global level. Therefore, modeling is one common alternative for estimating ET. With the goal to generate optimal fields of land surface states and fluxes, the Global Land Data Assimilation System (GLDAS) has been generating quality-controlled, spatially and temporally consistent, terrestrial hydrologic data, including ET and other variables that affect evaporation and transpiration, such as temperature, precipitation, humidity, wind, soil moisture, heat flux, and solar radiation. This poster presents the long-term ET climatology (mean and monthly), derived from the 61-year GLDAS-2 monthly 1.0 deg x 1.0 deg. NOAH model Experiment-1 data, and describes the basic characteristics of spatial and seasonal variations of the climatology. The time series of GLDAS-2 precipitation and radiation, and ET are also discussed to show the improvement of GLDAS-2 forcing data and model output over those from GLDAS-1.

  11. Precipitation Climatology on Titan-like Exomoons.

    Science.gov (United States)

    Tokano, Tetsuya

    2015-06-01

    The availability of liquid water on the surface on Earth's continents in part relies on the precipitation of water. This implies that the habitability of exomoons has to consider not only the surface temperature and atmospheric pressure for the presence of liquid water, but also the global precipitation climatology. This study explores the sensitivity of the precipitation climatology of Titan-like exomoons to these moons' orbital configuration using a global climate model. The precipitation rate primarily depends on latitude and is sensitive to the planet's obliquity and the moon's rotation rate. On slowly rotating moons the precipitation shifts to higher latitudes as obliquity is increased, whereas on quickly rotating moons the latitudinal distribution does not strongly depend on obliquity. Stellar eclipse can cause a longitudinal variation in the mean surface temperature and surface pressure between the subplanetary and antiplanetary side if the planet's obliquity and the moon's orbital distance are small. In this particular condition the antiplanetary side generally receives more precipitation than the subplanetary side. However, precipitation on exomoons with dense atmospheres generally occurs at any longitude in contrast to tidally locked exoplanets.

  12. 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

  13. 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.

  14. Global aerosol transport and consequences for the radiation budget

    International Nuclear Information System (INIS)

    Newiger, M.; Grassl, H.; Schussel, P.; Rehkopf, J.

    1984-01-01

    Man's activities may influence global climate by changing the atmospheric composition and surface characteristics and by waste heat. Most prominent within this discussion is the increase or decrease of radiatively active trace gases like CO/sub 2/, N/sub 2/O, O/sub 3/, and others. The general opinion is converging towards a greenhouse effect as a combined action of all trace gases, whose exact magnitude is uncertain mainly because of the unknown reaction of water cycle. The aim of our global 2-D (resolving latitude and height) aerosol transport model is the calculation of aerosol particle number density profiles as a function of latitude for present natural plus anthropogenic emissions. The aerosol transport model uses prescribed meridonal circulation, diffusivity factors and cloud climatology for January as well as July. All these latitude and height dependent input parameters were taken from well known sources. The fixed climatology excludes the feedback of aerosol particle parameter changes on mean circulation. However, the radiative parameters of six clouds types are modified, although they possess by adoption of the Telegadas and London (1954) cloud climatology prescribed amount and height. The inclusion of the feedback on mean circulation seems premature at present. Adding particles either accounting for natural emissions or natural anthropogenic emission and removing particles by all known sinks outside and within clouds gives us - for the stationary state - vertical profiles of aerosol number density in three sizes classes as a function of latitude. These profiles in turn are input for radiation flux calculations in clear and cloudy areas in order to assess net flux changes caused by the present aerosol load in comparison to a scenario without anthropogenic emissions. The net flux changes finally are compared to those calculated for increased CO/sub 2/ levels

  15. STEFLUX, a tool for investigating stratospheric intrusions: application to two WMO/GAW global stations

    Directory of Open Access Journals (Sweden)

    D. Putero

    2016-11-01

    Full Text Available Stratospheric intrusion (SI events are a topic of ongoing research, especially because of their ability to change the oxidation capacity of the troposphere and their contribution to tropospheric ozone levels. In this work, a novel tool called STEFLUX (Stratosphere-to-Troposphere Exchange Flux is presented, discussed, and used to provide a first long-term investigation of SI over two global hot-spot regions for climate change and air pollution: the southern Himalayas and the central Mediterranean Basin. The main purpose of STEFLUX is to obtain a fast-computing and reliable identification of the SI events occurring at a specific location and during a specified time window. It relies on a compiled stratosphere-to-troposphere exchange (STE climatology, which makes use of the ERA-Interim reanalysis dataset from the ECMWF, as well as a refined version of a well-established Lagrangian methodology. STEFLUX results are compared to the SI observations (SIO at two high-mountain WMO/GAW global stations in these climate hot spots, i.e., the Nepal Climate Observatory-Pyramid (NCO-P, 5079 m a.s.l. and Mt. Cimone (2165 m a.s.l., which are often affected by SI events. Compared to the observational datasets at the two specific measurement sites, STEFLUX is able to detect SI events on a regional scale. Furthermore, it has the advantage of retaining additional information concerning the pathway of stratospheric-affected air masses, such as the location of tropopause crossing and other meteorological parameters along the trajectories. However, STEFLUX neglects mixing and dilution that air masses undergo along their transport within the troposphere. Therefore, the regional-scale STEFLUX events cannot be expected to perfectly reproduce the point measurements at NCO-P and Mt. Cimone, which are also affected by small-scale (orographic circulations. Still, the seasonal variability in SI events according to SIO and STEFLUX agrees fairly well. By exploiting the

  16. 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.

  17. 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

  18. Recent increase in aerosol loading over the Australian arid zone

    Science.gov (United States)

    Mitchell, R. M.; Campbell, S. K.; Qin, Y.

    2009-10-01

    Collocated sun photometer and nephelometer measurements at Tinga Tingana in the Australian Outback over the decade 1997-2007 show a significant increase in aerosol loading following the onset of severe drought conditions in 2002. The mean mid-visible scattering coefficient obtained from nephelometer measurements over the period 2003-2007 is approximately double that recorded over the preceding 5 yr, with consistent trends in the column aerosol optical depth derived from the sun photometer. This increase is confined to the season of dust activity, particularly September to March. In contrast, background aerosol levels during May, June and July remained stable. The enhanced aerosol loadings during the latter 5 yr of the study period can be understood as a combination of dune destabilisation through loss of ephemeral vegetation and surface crust, and the changing supply of fluvial sediments to ephemeral lakes and floodplains within the Lake Eyre Basin. Major dust outbreaks are generally highly localised, although significant dust activity was observed at Tinga Tingana on 50% of days when a major event occurred elsewhere in the Lake Eyre Basin, suggesting frequent basin-wide dust mobilisation. Combined analysis of aerosol optical depth and scattering coefficient shows weak correlation between the surface and column aerosol (R2=0.24). The aerosol scale height is broadly distributed with a mode typically between 2-3 km, with clearly defined seasonal variation. Climatological analysis reveals bimodal structure in the annual cycle of aerosol optical depth, with a summer peak related to maximal dust activity, and a spring peak related to lofted fine-mode aerosol. There is evidence for an increase in near-surface aerosol during the period 2003-2007 relative to 1997-2002, consistent with an increase in dust activity. This accords with an independent finding of increasing aerosol loading over the Australian region as a whole, suggesting that rising dust activity over the Lake

  19. 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.

  20. 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.

  1. The OMI Aerosol Absorption Product: An A-train application

    Science.gov (United States)

    Torres, O.; Jethva, H. T.; Ahn, C.

    2017-12-01

    Because of the uniquely large sensitivity of satellite-measured near-UV radiances to absorption by desert dust, carbonaceous and volcanic ash aerosols, observations by a variety of UV-capable sensors have been routinely used over the last forty years in both qualitative and quantitative applications for estimating the absorption properties of these aerosol types. In this presentation we will discuss a multi-sensor application involving observations from A-train sensors OMI, AIRS and CALIOP for the creation of a 13-year record of aerosol optical depth (AOD) and single scattering albedo (SSA). Determination of aerosol type, in terms of particle size distribution and refractive index, is an important algorithmic step that requires using external information. AIRS CO measurements are used as carbonaceous aerosols tracer to differentiate this aerosol type from desert dust. On the other hand, the height of the absorbing aerosol layer, an important parameter in UV aerosol retrievals, is prescribed using a CALIOP-based climatology. The combined use of these observations in the developments of the OMI long-term AOD/SSA record will be discussed along with an evaluation of retrieval results using independent observations.

  2. Long-term changes in climatological calendar

    International Nuclear Information System (INIS)

    Jaagus, J.

    1997-01-01

    Trends in time series of climatic seasons in Tartu, Estonia, during 1891-1995 are analysed using regression analysis. Two intermediate seasons between autumn and winter (late autumn, early winter), and two ones between winter and spring (late winter and early spring) are determined. The climatic seasons correspond quite well to individual stages of annual cycling of nature. Results of linear regression analysis demonstrate changes in climatological calendar reflecting the influence of global warming. Climatic seasons of spring period have moved to earlier time, and seasons of autumn period to later time. Statistically significant trends were observed for beginning date of early spring (12 days earlier), summer (11 days earlier) and late autumn (8 days later). Beginning date of winter has shifted 12 days later. Duration of summer season has increased by two weeks and duration of winter season has decreased by the same time. (author)

  3. NORSEWInD satellite wind climatology

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Mouche, Alexis

    The EU-NORSEWInD project www.norsewind.eu has taken place from August 2008 to July 2012 (4 years). NORSEWInD is short for Northern Seas Wind Index database. In the project ocean surface wind observations from space have been retrieved, processed and analysed. The overall aim of the work...... is to provide new offshore wind climatology map for the entire area of interest based on satellite remote sensing. This has been based on Synthetic Aperture Radar (SAR) from Envisat ASAR using 9000 scenes re-processed with ECMWF wind direction and CMOD-IFR. The number of overlapping samples range from 450...... in the Irish Sea to more than 1200 in most of the Baltic Sea. Wind resource statistics include maps at 2 km spatial resolution of mean wind speed, Weibull A and k, and energy density at 10 m above sea level. Uncertainty estimates on the number of available samples for each of the four parameters are presented...

  4. The Global Climatology Network Precipitation data

    International Nuclear Information System (INIS)

    Peterson, T.C.; Easterling, D.R.; Eischeid, J.K.

    1993-01-01

    Several years ago, in response to growing concern about global climate change, the US National Climatic Data Center and the Carbon Dioxide Information Analysis Center undertook an effort to create a baseline global land surface climate data set called the Global Historical Climatology Network (GHCN, Vose et al., 1992). GHCN was created by merging several large existing climate data sets into one data base. Fifteen separate data sets went into the creation of the GHCN version 1.0. GHCN version 1.0 was released in 1992. It has 7,533 precipitation stations, but the number of stations varies with time. A slight majority (55%) have records in excess of 50 years, and a significant proportion (13%) have records in excess of 100 years. The longest period of record for any given station is 291 years (1697--1987 for Kew, United Kingdom)

  5. 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

  6. Climatology of lightning in the Czech Republic

    Science.gov (United States)

    Novák, Petr; Kyznarová, Hana

    2011-06-01

    The Czech Hydrometeorological Institute (CHMI) has utilized lightning data from the Central European Lightning Detection Network (CELDN) since 1999. The CELDN primarily focuses on the detection of cloud-to-ground (CG) lightning but intra-cloud (IC) lightning detection is also available. Lightning detection is used by the CHMI forecasters as an additional source to radar and satellite data for nowcasting of severe storms. Lightning data are also quantitatively used in automatic nowcasting applications. The quality of lightning data can be evaluated using their climatological characteristics. Climatological characteristics are also useful for defining decision thresholds that are valuable for human forecasters as well as for automatic nowcasting applications. The seven-year period from 2002 to 2008, which had relatively even-quality lightning data, was used to calculate the spatial and temporal distributions of lightning. The monthly number of CG strokes varies depending on the season. The highest number of CG strokes occurs during summer, with more than 20 days of at least five detected CG strokes on the Czech Republic territory in June and July. The least number of CG stokes occurs in winter, with less than three days per month having at least five detected CG stokes. The mean diurnal distribution of CG strokes peaks between 1500 and 1600 UTC and reaches a minimum between 0500 and 0800 UTC. The average spatial distribution of CG strokes shows sharp local maxima corresponding with the locations of the TV broadcast towers. The average spatial distribution of CG flash density, calculated on a 20 × 20 km grid, shows the maximum (3.23 flashes km - 2 year - 1 ) in the western part of Czech Republic and the minimum (0.92 flashes km - 2 year - 1 ) in the south-southeast of the Czech Republic. In addition, lightning characteristics related to the identified convective cells, such as distribution of the lightning stroke rates or relation to the radar derived by Vertically

  7. Geomagnetic activity forcing of the Northern Annular Mode via the stratosphere

    Directory of Open Access Journals (Sweden)

    D. R. Palamara

    2004-03-01

    Full Text Available We consider various aspects of the link between solar-modulated geomagnetic activity and the Northern Annular Mode (NAM. Our results indicate that the geomagnetic forcing of atmospheric circulation in the Northern Hemisphere is temporally and seasonally restricted, modulated by the Quasi-Biennial Oscillation (QBO, and reliant on stratosphere-troposphere coupling. When the data are restricted to January values after 1965, for years in which the January QBO is eastwards, the correlation coefficient between the geomagnetic AA index and the NAM is 0.85. These results can account for many of the enigmatic features of Northern Hemisphere circulation.

    Key words. Meterology and atmospheric dynamics (general circulation, climatology

  8. Climatological study of Saclay site from 1958 to 1966. General climatology

    International Nuclear Information System (INIS)

    Levrard, Andre

    1969-03-01

    This document complements the CEA-N--0463 note with additional climatological measurements performed between 1963 and 1966 at the CEA Saclay centre, extending this survey over the 1958 to 1966 period. The duration, height, number of days and intensity of precipitations, the temperatures and vertical thermal gradient, the fog/mist and the wind direction and speed are reported monthly, seasonally and annually and presented in tables and diagrams

  9. Global sea-to-air flux climatology for bromoform, dibromomethane and methyl iodide

    Directory of Open Access Journals (Sweden)

    F. Ziska

    2013-09-01

    Full Text Available Volatile halogenated organic compounds containing bromine and iodine, which are naturally produced in the ocean, are involved in ozone depletion in both the troposphere and stratosphere. Three prominent compounds transporting large amounts of marine halogens into the atmosphere are bromoform (CHBr3, dibromomethane (CH2Br2 and methyl iodide (CH3I. The input of marine halogens to the stratosphere has been estimated from observations and modelling studies using low-resolution oceanic emission scenarios derived from top-down approaches. In order to improve emission inventory estimates, we calculate data-based high resolution global sea-to-air flux estimates of these compounds from surface observations within the HalOcAt (Halocarbons in the Ocean and Atmosphere database (https://halocat.geomar.de/. Global maps of marine and atmospheric surface concentrations are derived from the data which are divided into coastal, shelf and open ocean regions. Considering physical and biogeochemical characteristics of ocean and atmosphere, the open ocean water and atmosphere data are classified into 21 regions. The available data are interpolated onto a 1°×1° grid while missing grid values are interpolated with latitudinal and longitudinal dependent regression techniques reflecting the compounds' distributions. With the generated surface concentration climatologies for the ocean and atmosphere, global sea-to-air concentration gradients and sea-to-air fluxes are calculated. Based on these calculations we estimate a total global flux of 1.5/2.5 Gmol Br yr−1 for CHBr3, 0.78/0.98 Gmol Br yr−1 for CH2Br2 and 1.24/1.45 Gmol Br yr−1 for CH3I (robust fit/ordinary least squares regression techniques. Contrary to recent studies, negative fluxes occur in each sea-to-air flux climatology, mainly in the Arctic and Antarctic regions. "Hot spots" for global polybromomethane emissions are located in the equatorial region, whereas methyl iodide emissions are enhanced in the

  10. Mid-latitude tropospheric ozone columns from the MOZAIC program: climatology and interannual variability

    Directory of Open Access Journals (Sweden)

    R. M. Zbinden

    2006-01-01

    Full Text Available Several thousands of ozone vertical profiles collected in the course of the MOZAIC programme (Measurements of Ozone, Water Vapour, Carbon Monoxide and Nitrogen Oxides by In-Service Airbus Aircraft from August 1994 to February 2002 are investigated to bring out climatological and interannual variability aspects. The study is centred on the most frequently visited MOZAIC airports, i.e. Frankfurt (Germany, Paris (France, New York (USA and the cluster of Tokyo, Nagoya and Osaka (Japan. The analysis focuses on the vertical integration of ozone from the ground to the dynamical tropopause and the vertical integration of stratospheric-origin ozone throughout the troposphere. The characteristics of the MOZAIC profiles: frequency of flights, accuracy, precision, and depth of the troposphere observed, are presented. The climatological analysis shows that the Tropospheric Ozone Column (TOC seasonal cycle ranges from a wintertime minimum at all four stations to a spring-summer maximum in Frankfurt, Paris, and New York. Over Japan, the maximum occurs in spring presumably because of the earlier springtime sun. The incursion of monsoon air masses into the boundary layer and into the mid troposphere then steeply diminishes the summertime value. Boundary layer contributions to the TOC are 10% higher in New York than in Frankfurt and Paris during spring and summer, and are 10% higher in Japan than in New York, Frankfurt and Paris during autumn and early spring. Local and remote anthropogenic emissions, and biomass burning over upstream regions of Asia may be responsible for the larger low- and mid-tropospheric contributions to the tropospheric ozone column over Japan throughout the year except during the summer-monsoon season. A simple Lagrangian analysis has shown that a minimum of 10% of the TOC is of stratospheric-origin throughout the year. Investigation of the short-term trends of the TOC over the period 1995–2001 shows a linear increase 0.7%/year in

  11. 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.

  12. Polar vortices on Earth and Mars: A comparative study of the climatology and variability from reanalyses.

    Science.gov (United States)

    Mitchell, D M; Montabone, L; Thomson, S; Read, P L

    2015-01-01

    Polar vortices on Mars provide case-studies to aid understanding of geophysical vortex dynamics and may help to resolve long-standing issues regarding polar vortices on Earth. Due to the recent development of the first publicly available Martian reanalysis dataset (MACDA), for the first time we are able to characterise thoroughly the structure and evolution of the Martian polar vortices, and hence perform a systematic comparison with the polar vortices on Earth. The winter atmospheric circulations of the two planets are compared, with a specific focus on the structure and evolution of the polar vortices. The Martian residual meridional overturning circulation is found to be very similar to the stratospheric residual circulation on Earth during winter. While on Earth this residual circulation is very different from the Eulerian circulation, on Mars it is found to be very similar. Unlike on Earth, it is found that the Martian polar vortices are annular, and that the Northern Hemisphere vortex is far stronger than its southern counterpart. While winter hemisphere differences in vortex strength are also reported on Earth, the contrast is not as large. Distinctions between the two planets are also apparent in terms of the climatological vertical structure of the vortices, in that the Martian polar vortices are observed to decrease in size at higher altitudes, whereas on Earth the opposite is observed. Finally, it is found that the Martian vortices are less variable through the winter than on Earth, especially in terms of the vortex geometry. During one particular major regional dust storm on Mars (Martian year 26), an equatorward displacement of the vortex is observed, sharing some qualitative characteristics of sudden stratospheric warmings on Earth.

  13. Aerosol Optical Depth Distribution in Extratropical Cyclones over the Northern Hemisphere Oceans

    Science.gov (United States)

    Naud, Catherine M.; Posselt, Derek J.; van den Heever, Susan C.

    2016-01-01

    Using Moderate Resolution Imaging Spectroradiometer and an extratropical cyclone database,the climatological distribution of aerosol optical depth (AOD) in extratropical cyclones is explored based solely on observations. Cyclone-centered composites of aerosol optical depth are constructed for the Northern Hemisphere mid-latitude ocean regions, and their seasonal variations are examined. These composites are found to be qualitatively stable when the impact of clouds and surface insolation or brightness is tested. The larger AODs occur in spring and summer and are preferentially found in the warm frontal and in the post-cold frontal regions in all seasons. The fine mode aerosols dominate the cold sector AODs, but the coarse mode aerosols display large AODs in the warm sector. These differences between the aerosol modes are related to the varying source regions of the aerosols and could potentially have different impacts on cloud and precipitation within the cyclones.

  14. 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.

  15. The Extrapolar SWIFT model (version 1.0): fast stratospheric ozone chemistry for global climate models

    Science.gov (United States)

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

    2018-03-01

    The Extrapolar SWIFT model is a fast ozone chemistry scheme for interactive calculation of the extrapolar stratospheric ozone layer in coupled general circulation models (GCMs). In contrast to the widely used prescribed ozone, the SWIFT ozone layer interacts with the model dynamics and can respond to atmospheric variability or climatological trends.The Extrapolar SWIFT model employs a repro-modelling approach, in which algebraic functions are used to approximate the numerical output of a full stratospheric chemistry and transport model (ATLAS). The full model solves a coupled chemical differential equation system with 55 initial and boundary conditions (mixing ratio of various chemical species and atmospheric parameters). Hence the rate of change of ozone over 24 h is a function of 55 variables. Using covariances between these variables, we can find linear combinations in order to reduce the parameter space to the following nine basic variables: latitude, pressure altitude, temperature, overhead ozone column and the mixing ratio of ozone and of the ozone-depleting families (Cly, Bry, NOy and HOy). We will show that these nine variables are sufficient to characterize the rate of change of ozone. An automated procedure fits a polynomial function of fourth degree to the rate of change of ozone obtained from several simulations with the ATLAS model. One polynomial function is determined per month, which yields the rate of change of ozone over 24 h. A key aspect for the robustness of the Extrapolar SWIFT model is to include a wide range of stratospheric variability in the numerical output of the ATLAS model, also covering atmospheric states that will occur in a future climate (e.g. temperature and meridional circulation changes or reduction of stratospheric chlorine loading).For validation purposes, the Extrapolar SWIFT model has been integrated into the ATLAS model, replacing the full stratospheric chemistry scheme. Simulations with SWIFT in ATLAS have proven that the

  16. 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.

  17. Sensitivity of boreal-summer circulation and precipitation to atmospheric aerosols in selected regions – Part 2: The Americas

    Directory of Open Access Journals (Sweden)

    G. Walker

    2009-10-01

    Full Text Available Aerosol perturbations over selected land regions are imposed in Version-4 of the Goddard Earth Observing System (GEOS-4 general circulation model (GCM to assess the influence of increasing aerosol concentrations on regional circulation patterns and precipitation in four selected regions: India, Africa, and North and South America. Part 1 of this paper addresses the responses to aerosol perturbations in India and Africa. This paper presents the same for aerosol perturbations over the Americas. GEOS-4 is forced with prescribed aerosols based on climatological data, which interact with clouds using a prognostic scheme for cloud microphysics including aerosol nucleation of water and ice cloud hydrometeors. In clear-sky conditions the aerosols interact with radiation. Thus the model includes comprehensive physics describing the aerosol direct and indirect effects on climate (hereafter ADE and AIE respectively. Each simulation is started from analyzed initial conditions for 1 May and was integrated through June-July-August of each of the six years: 1982–1987 to provide a 6-ensemble set. Results are presented for the difference between simulations with double the climatological aerosol concentration and one-half the climatological aerosol concentration for three experiments: two where the ADE and AIE are applied separately and one in which both the ADE and AIE are applied. The ADE and AIE both yield reductions in net radiation at the top of the atmosphere and surface while the direct absorption of shortwave radiation contributes a net radiative heating in the atmosphere. A large net heating of the atmosphere is also apparent over the subtropical North Atlantic Ocean that is attributable to the large aerosol perturbation imposed over Africa. This atmospheric warming and the depression of the surface pressure over North America contribute to a northward shift of the inter-Tropical Convergence Zone over northern South America, an increase in

  18. Sensitivity of boreal-summer circulation and precipitation to atmospheric aerosols in selected regions &ndash Part 2: The Americas

    Directory of Open Access Journals (Sweden)

    E. M. Wilcox

    2009-10-01

    Full Text Available Aerosol perturbations over selected land regions are imposed in Version-4 of the Goddard Earth Observing System (GEOS-4 general circulation model (GCM to assess the influence of increasing aerosol concentrations on regional circulation patterns and precipitation in four selected regions: India, Africa, and North and South America. Part 1 of this paper addresses the responses to aerosol perturbations in India and Africa. This paper presents the same for aerosol perturbations over the Americas. GEOS-4 is forced with prescribed aerosols based on climatological data, which interact with clouds using a prognostic scheme for cloud microphysics including aerosol nucleation of water and ice cloud hydrometeors. In clear-sky conditions the aerosols interact with radiation. Thus the model includes comprehensive physics describing the aerosol direct and indirect effects on climate (hereafter ADE and AIE respectively. Each simulation is started from analyzed initial conditions for 1 May and was integrated through June-July-August of each of the six years: 1982–1987 to provide a 6-ensemble set. Results are presented for the difference between simulations with double the climatological aerosol concentration and one-half the climatological aerosol concentration for three experiments: two where the ADE and AIE are applied separately and one in which both the ADE and AIE are applied. The ADE and AIE both yield reductions in net radiation at the top of the atmosphere and surface while the direct absorption of shortwave radiation contributes a net radiative heating in the atmosphere. A large net heating of the atmosphere is also apparent over the subtropical North Atlantic Ocean that is attributable to the large aerosol perturbation imposed over Africa. This atmospheric warming and the depression of the surface pressure over North America contribute to a northward shift of the inter-Tropical Convergence Zone over northern South America, an increase in

  19. 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

  20. A Lagrangian analysis of mid-latitude stratospheric ozone variability and long-term trends.

    Science.gov (United States)

    Koch, G.; Wernli, H.; Staehelin, J.; Peter, T.

    2002-05-01

    A systematic Lagrangian investigation is performed of wintertime high-resolution stratospheric ozone soundings at Payerne, Switzerland, from January 1970 to March 2001. For every ozone sounding, 10-day backward trajectories have been calculated on 16 isentropic levels using NCEP reanalysis data. Both the minimum/maximum latitude and potential vorticity (PV) averaged along the trajectories are used as indicators of the air parcels' ``origin''. The importance of transport for the understandin g of single ozone profiles is confirmed by a statistical analysis which shows that negative/positive ozone deviations gener ally coincide with transport from regions with climatologically low/high ozone values. The stable relationship between PV and ozone for the 32 year period indicates either no direct chemical impact or no temporal change of this impact. In the upper layer the PV-ozone relationship changes significantly after 1987 and a separate trend analysis for air masses transported from the polar, midlatitude and subtropical regions shows negative ozone trends in all three categories (with a maximum for the polar region). This is not direct evidence for, but would be in agreement with, an increased chemical ozone depletion in the Arctic since the late 1980s. The reasons for the negative trend in the mid-stratospheric air masses with subtropical origin that are in qualitative agreement with recent satellite observations are presently unknown.

  1. 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.

  2. 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

  3. Unexpected Climatological Behavior of MLT Gravity Wave Momentum Flux in the Lee of the Southern Andes Hot Spot

    Science.gov (United States)

    DeWit, R. J.; Janches, D.; Fritts, D. C.; Stockwell, R. G.; Coy, L.

    2017-01-01

    The Southern Argentina Agile MEteor Radar (SAAMER), located at Tierra del Fuego (53.7degS, 67.7degW), has been providing near-continuous high-resolution measurements of winds and high-frequency gravity wave (GW) momentum fluxes of the mesopause region since May 2008. As SAAMER is located in the lee of the largest seasonal GW hot spot on Earth, this is a key location to study GWs and their interaction with large-scale motions. GW momentum flux climatologies are shown for the first time for this location and discussed in light of these unique dynamics. Particularly, the large eastward GW momentum fluxes during local winter are surprising, as these observations cannot be explained by the direct upward propagation of expected large-amplitude mountain waves (MWs) through the eastward stratospheric jet. Instead, these results are interpreted as secondary GWs propagating away from stratospheric sources over the Andes accompanying MW breaking over the Southern Andes.

  4. 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...

  5. 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

  6. 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

  7. 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

  8. 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

  9. On the representation of aerosol activation and its influence on model-derived estimates of the aerosol indirect effect

    Science.gov (United States)

    Rothenberg, Daniel; Avramov, Alexander; Wang, Chien

    2018-06-01

    Interactions between aerosol particles and clouds contribute a great deal of uncertainty to the scientific community's understanding of anthropogenic climate forcing. Aerosol particles serve as the nucleation sites for cloud droplets, establishing a direct linkage between anthropogenic particulate emissions and clouds in the climate system. To resolve this linkage, the community has developed parameterizations of aerosol activation which can be used in global climate models to interactively predict cloud droplet number concentrations (CDNCs). However, different activation schemes can exhibit different sensitivities to aerosol perturbations in different meteorological or pollution regimes. To assess the impact these different sensitivities have on climate forcing, we have coupled three different core activation schemes and variants with the CESM-MARC (two-Moment, Multi-Modal, Mixing-state-resolving Aerosol model for Research of Climate (MARC) coupled with the National Center for Atmospheric Research's (NCAR) Community Earth System Model (CESM; version 1.2)). Although the model produces a reasonable present-day CDNC climatology when compared with observations regardless of the scheme used, ΔCDNCs between the present and preindustrial era regionally increase by over 100 % in zonal mean when using the most sensitive parameterization. These differences in activation sensitivity may lead to a different evolution of the model meteorology, and ultimately to a spread of over 0.8 W m-2 in global average shortwave indirect effect (AIE) diagnosed from the model, a range which is as large as the inter-model spread from the AeroCom intercomparison. Model-derived AIE strongly scales with the simulated preindustrial CDNC burden, and those models with the greatest preindustrial CDNC tend to have the smallest AIE, regardless of their ΔCDNC. This suggests that present-day evaluations of aerosol-climate models may not provide useful constraints on the magnitude of the AIE, which

  10. Tower Mesonetwork Climatology and Interactive Display Tool

    Science.gov (United States)

    Case, Jonathan L.; Bauman, William H., III

    2004-01-01

    Forecasters at the 45th Weather Squadron and Spaceflight Meteorology Group use data from the tower network over the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) to evaluate Launch Commit Criteria, and issue and verify forecasts for ground operations. Systematic biases in these parameters could adversely affect an analysis, forecast, or verification. Also, substantial geographical variations in temperature and wind speed can occur under specific wind directions. To address these concerns, the Applied Meteorology Unit (AMU) developed a climatology of temperatures and winds from the tower network, and identified the geographical variation and significant tower biases. The mesoclimate is largely driven by the complex land-water interfaces across KSC/CCAFS. Towers with close proximity to water typically had much warmer nocturnal temperatures and higher wind speeds throughout the year. The strongest nocturnal wind speeds occurred from October to March whereas the strongest mean daytime wind speeds occurred from February to May. These results of this project can be viewed by forecasters through an interactive graphical user interface developed by the AMU. The web-based interface includes graphical and map displays of mean, standard deviation, bias, and data availability for any combination of towers, variables, months, hours, and wind directions.

  11. An empirical framework for tropical cyclone climatology

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Nam-Young [Korea Meteorological Administration, Seoul (Korea, Republic of); Florida State University, Tallahassee, FL (United States); Elsner, James B. [Florida State University, Tallahassee, FL (United States)

    2012-08-15

    An empirical approach for analyzing tropical cyclone climate is presented. The approach uses lifetime-maximum wind speed and cyclone frequency to induce two orthogonal variables labeled ''activity'' and ''efficiency of intensity''. The paired variations of activity and efficiency of intensity along with the opponent variations of frequency and intensity configure a framework for evaluating tropical cyclone climate. Although cyclone activity as defined in this framework is highly correlated with the commonly used exponent indices like accumulated cyclone energy, it does not contain cyclone duration. Empirical quantiles are used to determine threshold intensity levels, and variant year ranges are used to find consistent trends in tropical cyclone climatology. In the western North Pacific, cyclone activity is decreasing despite increases in lifetime-maximum intensity. This is due to overwhelming decreases in cyclone frequency. These changes are also explained by an increasing efficiency of intensity. The North Atlantic shows different behavior. Cyclone activity is increasing due to increasing frequency and, to a lesser extent, increasing intensity. These changes are also explained by a decreasing efficiency of intensity. Tropical cyclone trends over the North Atlantic basin are more consistent over different year ranges than tropical cyclone trends over the western North Pacific. (orig.)

  12. 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.

  13. Hanford Site Climatological Summary 2004 with Historical Data

    International Nuclear Information System (INIS)

    Hoitink, Dana J.; Ramsdell, James V.; Burk, Kenneth W.; Shaw, William J.

    2005-01-01

    This document presents the climatological data measured on the DOE Hanford Site for calendar year 2004. This report contains updated historical information for temperature, precipitation, wind, and normal and extreme values of temperature, and precipitation

  14. Global Historical Climatology Network - Daily (GHCN-Daily), Version 3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Historical Climatology Network - Daily (GHCN-Daily) dataset integrates daily climate observations from approximately 30 different data sources. Version 3...

  15. Global Precipitation Climatology Project (GPCP) - Daily, Version 1.2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Precipitation Climatology Project (GPCP) comprises a total of 27 products. The Version 1.2 Daily product covers the period October 1998 to the present,...

  16. AFSC/ABL: Auke Bay Climatology 1959-2013

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data set includes available climatological and related physical environmental records for Auke Bay, Auke Creek and Auke Lake beginning in 1959. Daily high and low...

  17. Global Precipitation Climatology Project (GPCP) - Pentad, Version 2.2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Precipitation Climatology Project (GPCP) comprises a total of 27 products. The Version 2.2 Pentad product covers the period January 1979 to the present,...

  18. Global Historical Climatology Network - Monthly (GHCN-M), Version 3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Please note, GHCN-Monthly provides climatological observations for four elements; monthly mean maximum temperature, minimum temperature, mean temperature, and...

  19. 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.

  20. 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.

  1. Tropospheric Ozone Climatology over Irene, South Africa, From 1990-1994 and 1998-2002

    Science.gov (United States)

    Diab, R. D.; Thompson, A. M.; Marl, K.; Ramsay, L.; Coetzee, G. J. R.

    2004-01-01

    This paper describes ozone profiles from sonde data during the period of NASA s TRACE-A and the more recent SHADOZ (Southern Hemisphere Additional Ozonesondes) period. The data were taken by the South African Weather Service at the Irene (25 deg.54 min S; 28 deg. 13 min. E) station near Pretoria, South Africa, an area that is a unique mixture of local industry, heavy biofuels use and importation of biomass burning ozone from neighboring countries to the north. The main findings are: (1) With its geographical position at the edge of the subtropical transition zone, mid- latitude dynamical influences are evident at Irene, predominantly in winter when upper tropospheric ozone is enhanced as a result of stratospheric-tropospheric exchange. (2) There has been an increase in the near-surface ozone amount between the early 1990s and a decade later, presumably due to an influx of rural population toward the Johannesburg-Pretoria area, as well as with industrial growth and development. (3) Most significant for developing approaches for satellite ozone profile climatologies, cluster analysis has enabled the delineation of a background and "most polluted" profile. Enhancements of at least 30% occur throughout the troposphere in spring and in certain layers increases of 100 % are observed.

  2. A daytime climatological distribution of high opaque ice cloud classes over the Indian summer monsoon region observed from 25-year AVHRR data

    Directory of Open Access Journals (Sweden)

    A. Devasthale

    2009-06-01

    Full Text Available A daytime climatological spatio-temporal distribution of high opaque ice cloud (HOIC classes over the Indian subcontinent (0–40° N, 60° E–100° E is presented using 25-year data from the Advanced Very High Resolution Radiometers (AVHRRs for the summer monsoon months. The HOICs are important for regional radiative balance, precipitation and troposphere-stratosphere exchange. In this study, HOICs are sub-divided into three classes based on their cloud top brightness temperatures (BT. Class I represents very deep convection (BT<220 K. Class II represents deep convection (220 K<=BT<233 K and Class III background convection (233 K<=BT<253 K. Apart from presenting finest spatial resolution (0.1×0.1 degrees and long-term climatology of such cloud classes from AVHRRs to date, this study for the first time illustrates on (1 how these three cloud classes are climatologically distributed during monsoon months, and (2 how their distribution changes during active and break monsoon conditions. It is also investigated that how many deep convective clouds reach the tropopause layer during individual monsoon months. It is seen that Class I and Class II clouds dominate the Indian subcontinent during monsoon. The movement of monsoon over continent is very well reflected in these cloud classes. During monsoon breaks strong suppression of convective activity is observed over the Arabian Sea and the western coast of India. On the other hand, the presence of such convective activity is crucial for active monsoon conditions and all-India rainfall. It is found that a significant fraction of HOICs (3–5% reach the tropopause layer over the Bay of Bengal during June and over the north and northeast India during July and August. Many cases are observed when clouds penetrate the tropopause layer and reach the lower stratosphere. Such cases mostly occur during June compared to the other months.

  3. Tropospheric ozone climatology at two Southern Hemisphere tropical/subtropical sites, (Reunion Island and Irene, South Africa from ozonesondes, LIDAR, and in situ aircraft measurements

    Directory of Open Access Journals (Sweden)

    G. Clain

    2009-03-01

    Full Text Available This paper presents a climatology and trends of tropospheric ozone in the Southwestern Indian Ocean (Reunion Island and South Africa (Irene and Johannesburg. This study is based on a multi-instrumental dataset: PTU-O3 ozonesondes, DIAL LIDAR and MOZAIC airborne instrumentation.

    The seasonal profiles of tropospheric ozone at Reunion Island have been calculated from two different data sets: ozonesondes and LIDAR. The two climatological profiles are similar, except in austral summer when the LIDAR profiles show greater values in the free troposphere, and in the upper troposphere when the LIDAR profiles show lower values during all seasons. These results show that the climatological value of LIDAR profiles must be discussed with care since LIDAR measurements can be performed only under clear sky conditions, and the upper limit of the profile depends on the signal strength.

    In addition, linear trends have been calculated from ozonesonde data at Reunion and Irene. Considering the whole tropospheric column, the trend is slightly positive for Reunion, and more clearly positive for Irene. Trend calculations have also been made separating the troposphere into three layers, and separating the dataset into seasons. Results show that the positive trend for Irene is governed by the lower layer that is affected by industrial pollution and biomass burning. On the contrary, for Reunion Island, the strongest trends are observed in the upper troposphere, and in winter when stratosphere-troposphere exchange is more frequently expected.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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).

  11. Uncertainties in Climatological Seawater Density Calculations

    Science.gov (United States)

    Dai, Hao; Zhang, Xining

    2018-03-01

    In most applications, with seawater conductivity, temperature, and pressure data measured in situ by various observation instruments e.g., Conductivity-Temperature-Depth instruments (CTD), the density which has strong ties to ocean dynamics and so on is computed according to equations of state for seawater. This paper, based on density computational formulae in the Thermodynamic Equation of Seawater 2010 (TEOS-10), follows the Guide of the expression of Uncertainty in Measurement (GUM) and assesses the main sources of uncertainties. By virtue of climatological decades-average temperature/Practical Salinity/pressure data sets in the global ocean provided by the National Oceanic and Atmospheric Administration (NOAA), correlation coefficients between uncertainty sources are determined and the combined standard uncertainties uc>(ρ>) in seawater density calculations are evaluated. For grid points in the world ocean with 0.25° resolution, the standard deviations of uc>(ρ>) in vertical profiles cover the magnitude order of 10-4 kg m-3. The uc>(ρ>) means in vertical profiles of the Baltic Sea are about 0.028kg m-3 due to the larger scatter of Absolute Salinity anomaly. The distribution of the uc>(ρ>) means in vertical profiles of the world ocean except for the Baltic Sea, which covers the range of >(0.004,0.01>) kg m-3, is related to the correlation coefficient r>(SA,p>) between Absolute Salinity SA and pressure p. The results in the paper are based on sensors' measuring uncertainties of high accuracy CTD. Larger uncertainties in density calculations may arise if connected with lower sensors' specifications. This work may provide valuable uncertainty information required for reliability considerations of ocean circulation and global climate models.

  12. Fog and dew climatology over Hisar, India

    International Nuclear Information System (INIS)

    Surender, S.; Diwan, S.; Rao, V.U.M.

    2006-05-01

    In many arid and semi-arid areas, pumped ground water and the water from streams, rivers and reservoirs is no longer sufficient to cover the ever increasing water demand. Therefore new interest in 'marginal' water resources like fog and dew harvesting are to be developed after studying climatology of these parameters in a region. The observations on dew and fog events recorded at Hisar, representing semi-arid region of India during winter season (October to March) for the period 1980 to 2005 have been analyzed. The total annual dew amount in winter season ranged between 33 mm (1987-88) and 79 mm (1981-82) during the period under study. The seasonal dewfall showed a decreasing trend of 1.4 mm during the period under investigation. Average maximum dew events (26.1) were recorded during November and average minimum dew events were recorded in February. In a particular season, the highest dew events (168) were observed during the winter seasons of 1982-83 and 1983-84, whereas, the minimum number of dew events (97) was reported during 1998-99. Interestingly, an increasing trend (1.3 day/season) in occurrence of fog events was seen. Average maximum foggy events (8.7) recorded in a month were observed in January. In a particular season, the maximum foggy events (41) were recorded during 2002-03 and the minimum (2) during 1983-84. To achieve the objective of alternate source of water and to assess the impact of dew and fog on agricultural crops for their growth and development, inputs from various specialized disciplines and allied sciences engaged in meteorological applications along with forecasting skills from non scientific quarters are needed to predict the weather parameter accurately, thus the active cooperation between meteorological/remote sensing agencies, agricultural organizations and farming community is needed for sustainable agricultural development in scarce/limited water availability regions. (author)

  13. Southern Hemisphere Upper Thermospheric Wind Climatology

    Science.gov (United States)

    Dhadly, M. S.; Emmert, J. T.; Drob, D. P.

    2017-12-01

    This study is focused on the poorly understood large-scale upper thermospheric wind dynamics in the southern polar cap, auroral, and mid latitudes. The gaps in our understanding of the dynamic high-latitude thermosphere are largely due to the sparseness of thermospheric wind measurements. Using data from current observational facilities, it is unfeasible to construct a synoptic picture of the Southern Hemisphere upper thermospheric winds. However, enough data with wide spatial and temporal coverage have accumulated to construct a meaningful statistical analysis of winds as function of season, magnetic latitude, and magnetic local time. We use long-term data from nine ground-based stations located at different southern high latitudes and three space-based instruments. These diverse data sets possess different geometries and different spatial and solar coverage. The major challenge of the effort is to combine these disparate sources of data into a coherent picture while overcoming the sampling limitations and biases among the datasets. Our preliminary analyses show mutual biases present among some of them. We first address the biases among various data sets and then combine them in a coherent way to construct maps of neutral winds for various seasons. We then validate the fitted climatology against the observational data and compare with corresponding fits of 25 years of simulated winds from the National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model. This study provides critical insight into magnetosphere-ionosphere-thermosphere coupling and sets a necessary benchmark for validating new observations and tuning first-principles models.

  14. A Seasonal Air Transport Climatology for Kenya

    Science.gov (United States)

    Gatebe, C. K.; Tyson, P. D.; Annegarn, H.; Piketh, S.; Helas, G.

    1998-01-01

    A climatology of air transport to and from Kenya has been developed using kinematic trajectory modeling. Significant months for trajectory analysis have been determined from a classification of synoptic circulation fields. Five-point back and forward trajectory clusters to and from Kenya reveal that the transport corridors to Kenya are clearly bounded and well defined. Air reaching the country originates mainly from the Saharan region and northwestern Indian Ocean of the Arabian Sea in the northern hemisphere and from the Madagascan region of the Indian Ocean in the southern hemisphere. Transport from each of these source regions show distinctive annual cycles related to the northeasterly Asian monsoon and the southeasterly trade wind maximum over Kenya in May. The Saharan transport in the lower troposphere is at a maximum when the subtropical high over northern Africa is strongly developed in the boreal winter. Air reaching Kenya between 700 and 500 hPa is mainly from Sahara and northwest India Ocean flows in the months of January and March, which gives way to southwest Indian Ocean flow in May and November. In contrast, air reaching Kenya at 400 hPa is mainly from southwest Indian Ocean in January and March, which is replaced by Saharan transport in May and November. Transport of air from Kenya is invariant, both spatially and temporally, in the tropical easterlies to the Congo Basin and Atlantic Ocean in comparison to the transport to the country. Recirculation of air has also been observed, but on a limited and often local scale and not to the extent reported in southern Africa.

  15. EFFECTS OF NON-METHANE HYDROCARBONS ON LOWER STRATOSPHERIC AND UPPER TROPOSPHERIC 2-D ZONAL AVERAGE MODEL CLIMATOLOGY. (R826384)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  16. 16 year climatology of cirrus clouds over a tropical station in southern India using ground and space-based lidar observations

    Science.gov (United States)

    Pandit, A. K.; Gadhavi, H. S.; Venkat Ratnam, M.; Raghunath, K.; Rao, S. V. B.; Jayaraman, A.

    2015-06-01

    16 year (1998-2013) climatology of cirrus clouds and their macrophysical (base height, top height and geometrical thickness) and optical properties (cloud optical thickness) observed using a ground-based lidar over Gadanki (13.5° N, 79.2° E), India, is presented. The climatology obtained from the ground-based lidar is compared with the climatology obtained from seven and half years (June 2006-December 2013) of Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) observations. A very good agreement is found between the two climatologies in spite of their opposite viewing geometries and difference in sampling frequencies. Nearly 50-55% of cirrus clouds were found to possess geometrical thickness less than 2 km. Ground-based lidar is found to detect more number of sub-visible clouds than CALIOP which has implications for global warming studies as sub-visible cirrus clouds have significant positive radiative forcing. Cirrus clouds with mid-cloud temperatures between -50 to -70 °C have a mean geometrical thickness greater than 2 km in contrast to the earlier reported value of 1.7 km. Trend analyses reveal a statistically significant increase in the altitude of sub-visible cirrus clouds which is consistent with the recent climate model simulations. Also, the fraction of sub-visible cirrus cloud is found to be increasing during the last sixteen years (1998 to 2013) which has implications to the temperature and water vapour budget in the tropical tropopause layer.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. The Adaptive Ecosystem Climatology (AEC): Design and Development

    Science.gov (United States)

    deRada, S.; Penta, B.; McCarthy, S.; Gould, R. W., Jr.

    2016-02-01

    The concept of ecosystem-based management (EBM), recently introduced to rectify the shortcomings of single-species management policies, has been widely accepted as a basis for the conservation and management of natural resources. In line with NOAA's Integrated Ecosystem Assessment (IEA) Program, EBM is an integrated approach that considers the entire ecosystem and the interactions among species rather than focusing on individual components. This integrative approach relies on heterogeneous data, physical as well as biogeochemical data, among many others. Relative to physical data, however, marine biogeochemical records, also critical in IEA and EBM, are still lacking, both in terms of mature models and in terms of observational data availability. TheAdaptive Ecosystem Climatology (AEC) was conceived as a novel approach to address these limitations, mitigating the shortcomings of the individual components and combining their strengths to enhance decision-making activities. AEC is designed on the concept that a high-frequency climatology can be used as a baseline into which available observational data can be ingested to produce a higher accuracy product. In the absence of observations, the climatology acts as a best estimate. AEC was developed using a long-term simulation of a coupled biophysical numerical model configured for the Gulf of Mexico. Using the model results, we constructed a three-dimensional, dynamically balanced, gridded, static climatology for each calendar day. Using this `static' climatology as a background `first guess', observations from a particular date are ingested via optimal interpolation to `nudge' the climatology toward current conditions, thus providing representative fields for that date (adaptive climatology). With this adaptive approach, AEC can support a variety of EBM objectives, from fisheries, to resource management, to coastal resilience.

  2. 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...

  3. Estimating Climatological Bias Errors for the Global Precipitation Climatology Project (GPCP)

    Science.gov (United States)

    Adler, Robert; Gu, Guojun; Huffman, George

    2012-01-01

    A procedure is described to estimate bias errors for mean precipitation by using multiple estimates from different algorithms, satellite sources, and merged products. The Global Precipitation Climatology Project (GPCP) monthly product is used as a base precipitation estimate, with other input products included when they are within +/- 50% of the GPCP estimates on a zonal-mean basis (ocean and land separately). The standard deviation s of the included products is then taken to be the estimated systematic, or bias, error. The results allow one to examine monthly climatologies and the annual climatology, producing maps of estimated bias errors, zonal-mean errors, and estimated errors over large areas such as ocean and land for both the tropics and the globe. For ocean areas, where there is the largest question as to absolute magnitude of precipitation, the analysis shows spatial variations in the estimated bias errors, indicating areas where one should have more or less confidence in the mean precipitation estimates. In the tropics, relative bias error estimates (s/m, where m is the mean precipitation) over the eastern Pacific Ocean are as large as 20%, as compared with 10%-15% in the western Pacific part of the ITCZ. An examination of latitudinal differences over ocean clearly shows an increase in estimated bias error at higher latitudes, reaching up to 50%. Over land, the error estimates also locate regions of potential problems in the tropics and larger cold-season errors at high latitudes that are due to snow. An empirical technique to area average the gridded errors (s) is described that allows one to make error estimates for arbitrary areas and for the tropics and the globe (land and ocean separately, and combined). Over the tropics this calculation leads to a relative error estimate for tropical land and ocean combined of 7%, which is considered to be an upper bound because of the lack of sign-of-the-error canceling when integrating over different areas with a

  4. 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

  5. Sensitive detection of aerosol effect on simulated IASI spectral radiance

    International Nuclear Information System (INIS)

    Quan, X.; Huang, H.-L.; Zhang, L.; Weisz, E.; Cao, X.

    2013-01-01

    Guided by radiative transfer modeling of the effects of dust (aerosol) on satellite thermal infrared radiance by many different imaging radiometers, in this article, we present the aerosol-effected satellite radiative signal changes in the top of atmosphere (TOA). The simulation of TOA radiance for Infrared Atmospheric Sounding Interferometer (IASI) is performed by using the RTTOV fast radiative transfer model. The model computation is carried out with setting representative geographical atmospheric models and typical default aerosol climatological models under clear sky condition. The radiative differences (in units of equivalent black body brightness temperature differences (BTDs)) between simulated radiances without consideration of the impact of aerosol (Aerosol-free) and with various aerosol models (Aerosol-modified) are calculated for the whole IASI spectrum between 3.62 and 15.5 μm. The comparisons of BTDs are performed through 11 aerosol models in 5 classified atmospheric models. The results show that the Desert aerosol model has the most significant impact on IASI spectral simulated radiances than the other aerosol models (Continental, Urban, Maritime types and so on) in Mid-latitude Summer, contributing to the mineral aerosol components contained. The value of BTDs could reach up to 1 K at peak points. The atmospheric window spectral region between 900 and 1100 cm −1 (9.09–11.11 μm) is concentrated after the investigation for the largest values of aerosol-affected radiance differences. BTDs in IASI spectral region between 645 and 1200 cm −1 occupies the largest oscillation and the major part of the whole spectrum. The IASI highest window peak-points channels (such as 9.4 and 10.2 μm) are obtained finally, which are the most sensitive ones to the simulated IASI radiance. -- Highlights: ► Sensitive study of aerosol effect on simulated IASI spectral radiance is performed. ► The aerosol components have influenced IASI spectral regions

  6. Eight Year Climatologies from Observational (AIRS) and Model (MERRA) Data

    Science.gov (United States)

    Hearty, Thomas; Savtchenko, Andrey; Won, Young-In; Theobalk, Mike; Vollmer, Bruce; Manning, Evan; Smith, Peter; Ostrenga, Dana; Leptoukh, Greg

    2010-01-01

    We examine climatologies derived from eight years of temperature, water vapor, cloud, and trace gas observations made by the Atmospheric Infrared Sounder (AIRS) instrument flying on the Aqua satellite and compare them to similar climatologies constructed with data from a global assimilation model, the Modern Era Retrospective-Analysis for Research and Applications (MERRA). We use the AIRS climatologies to examine anomalies and trends in the AIRS data record. Since sampling can be an issue for infrared satellites in low earth orbit, we also use the MERRA data to examine the AIRS sampling biases. By sampling the MERRA data at the AIRS space-time locations both with and without the AIRS quality control we estimate the sampling bias of the AIRS climatology and the atmospheric conditions where AIRS has a lower sampling rate. While the AIRS temperature and water vapor sampling biases are small at low latitudes, they can be more than a few degrees in temperature or 10 percent in water vapor at higher latitudes. The largest sampling biases are over desert. The AIRS and MERRA data are available from the Goddard Earth Sciences Data and Information Services Center (GES DISC). The AIRS climatologies we used are available for analysis with the GIOVANNI data exploration tool. (see, http://disc.gsfc.nasa.gov).

  7. Multiangle Imaging Spectroradiometer (MISR) Global Aerosol Optical Depth Validation Based on 2 Years of Coincident Aerosol Robotic Network (AERONET) Observations

    Science.gov (United States)

    Kahn, Ralph A.; Gaitley, Barbara J.; Martonchik, John V.; Diner, David J.; Crean, Kathleen A.; Holben, Brent

    2005-01-01

    Performance of the Multiangle Imaging Spectroradiometer (MISR) early postlaunch aerosol optical thickness (AOT) retrieval algorithm is assessed quantitatively over land and ocean by comparison with a 2-year measurement record of globally distributed AERONET Sun photometers. There are sufficient coincident observations to stratify the data set by season and expected aerosol type. In addition to reporting uncertainty envelopes, we identify trends and outliers, and investigate their likely causes, with the aim of refining algorithm performance. Overall, about 2/3 of the MISR-retrieved AOT values fall within [0.05 or 20% x AOT] of Aerosol Robotic Network (AERONET). More than a third are within [0.03 or 10% x AOT]. Correlation coefficients are highest for maritime stations (approx.0.9), and lowest for dusty sites (more than approx.0.7). Retrieved spectral slopes closely match Sun photometer values for Biomass burning and continental aerosol types. Detailed comparisons suggest that adding to the algorithm climatology more absorbing spherical particles, more realistic dust analogs, and a richer selection of multimodal aerosol mixtures would reduce the remaining discrepancies for MISR retrievals over land; in addition, refining instrument low-light-level calibration could reduce or eliminate a small but systematic offset in maritime AOT values. On the basis of cases for which current particle models are representative, a second-generation MISR aerosol retrieval algorithm incorporating these improvements could provide AOT accuracy unprecedented for a spaceborne technique.

  8. 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.

  9. 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.

  10. The SHADOZ Data Base: History, Archive Web Guide, and Sample Climatologies

    Science.gov (United States)

    White, J. C.; Thompson, A. M.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    SHADOZ (Southern Hemisphere Additional Ozonesonde) is a project to augment and archive ozonesonde data from ten tropical and subtropical ozone stations. Started in 1998 by NASA's Goddard Space Flight Center and other US and international co-investigators, SHADOZ is an important tool for tropospheric ozone research in the equatorial region. The rationale for SHADOZ is to: (1) validate and improve remote sensing techniques (e.g., the Total Ozone Mapping Spectrometer (TOMS) satellite) for estimating tropical ozone, (2) contribute to climatology and trend analyses of tropical ozone and (3) provide research topics to scientists and educate students, especially in participating countries. SHADOZ is envisioned as a data service to the global scientific community by providing a central public archive location via the internet: http://code9l6.gsfc.nasa.gov/Data_services/shadoz. While the SHADOZ website maintains a standard data format for the archive, it also informs the data users on the differing stations' preparation techniques and data treatment. The presentation navigates through the SHADOZ website to access each station's sounding data and summarize each station's characteristics. Since the start of the project in 1998, the SHADOZ archive has accumulated over 600 ozonesonde profiles and received over 30,000 outside data requests. Data also includes launches from various SHADOZ supported field campaigns, such as, the Indian Ocean Experiment (INDOEX), Sounding of Ozone and Water in the Equatorial Region (SOWER) and Aerosols99 Atlantic Cruise. Using data from the archive, sample climatologies and profiles from selected stations and campaigns will be shown.

  11. 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.

  12. 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

  13. 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)

  14. MERIS albedo climatology for FRESCO+ O2 A-band cloud retrieval

    Directory of Open Access Journals (Sweden)

    Y. Zhou

    2011-03-01

    trace gas retrieval which relies on accurate cloud information at small cloud fractions. In addition, overestimates along coastlines and underestimates in the Intertropical Convergence Zone introduced by the GOME LER were eliminated. While effective cloud fractions over the Saharan desert and the Arabian peninsula are successfully reduced in January, they are still too high in July relative to HICRU due to FRESCO+'s large sensitivity to albedo inaccuracies of highly reflecting targets and inappropriate aerosol information which hampers an accurate albedo retrieval. Finally, NO2 tropospheric vertical column densities and O3 total columns were derived with the FRESCO+ cloud parameters from the new dataset and it is found that the MERIS BSA climatology has a pronounced and beneficial effect on regional scale. Apart from FRESCO+, the new MERIS albedo dataset is applicable to any cloud retrieval algorithms using the O2 A-band or the O2-O2 absorption band around 477 nm. Moreover, the by-product of BSA at 442 nm can be used in NO2 remote sensing and the BSA at 620 nm, 665 nm, and 681 nm could be integrated in current H2O retrievals.

  15. 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

  16. 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?

  17. 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.

  18. 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

  19. 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.

  20. Towards a generalization procedure for WRF mesoscale wind climatologies

    DEFF Research Database (Denmark)

    Hahmann, Andrea N.; Casso, P.; Campmany, E.

    We present a method for generalizing wind climatologies generated from mesoscale model output (e.g. the Weather, Research and Forecasting (WRF) model.) The generalization procedure is based on Wind Atlas framework of WAsP and KAMM/WAsP, and been extensively in wind resources assessment in DTU Wind...... generalized wind climatologies estimated by the microscale model WAsP and the methodology presented here. For the Danish wind measurements the mean absolute error in the ‘raw’ wind speeds is 9.2%, while the mean absolute error in the generalized wind speeds is 4.1%. The generalization procedure has been...

  1. Wind Climate Analyses for SRTC's Central Climatology Site

    International Nuclear Information System (INIS)

    Weber, A.H.

    2003-01-01

    This report was written to present climatological summaries of the wind data at the Central Climatology (CC) tower in a convenient format and to point out some features of the wind speed and direction that have not been widely appreciated in the past. Short-term (two-week) wind roses provide a means to demonstrate the temporal and spatial relationships that wind speed and direction undergo using a ten-year database from the CC tower. These relationships are best demonstrated by examining the figures provided in this report or looking at loops of computer-generated images provided by the authors

  2. 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.

  3. Long-term Aerosol Lidar Measurements At CNR-IMAA

    Science.gov (United States)

    Mona, L.; Amodeo, A.; D'Amico, G.; Pandolfi, M.; Pappalardo, G.

    2006-12-01

    Actual estimations of the aerosol effect on the radiation budget are affected by a large uncertainties mainly due to the high inhomogeneity and variability of atmospheric aerosol, in terms of concentration, shape, size distribution, refractive index and vertical distribution. Long-term measurements of vertical profiles of aerosol optical properties are needed to reduce these uncertainties. At CNR-IMAA (40° 36'N, 15° 44' E, 760 m above sea level), a lidar system for aerosol study is operative since May 2000 in the framework of EARLINET (European Aerosol Research Lidar Network). Until August 2005, it provided independent measurements of aerosol extinction and backscatter at 355 nm and aerosol backscatter profiles at 532 nm. After an upgrade of the system, it provides independent measurements of aerosol extinction and backscatter profiles at 355 and 532 nm, and of aerosol backscatter profiles at 1064 nm and depolarization ratio at 532 nm. For these measurements, lidar ratio at 355 and 532 nm and Angstrom exponent profiles at 355/532 nm are also obtained. Starting on May 2000, systematic measurements are performed three times per week according to the EARLINET schedule and further measurements are performed in order to investigate particular events, like dust intrusions, volcanic eruptions and forest fires. A climatological study has been carried out in terms of the seasonal behavior of the PBL height and of the aerosol optical properties calculated inside the PBL itself. In the free troposphere, an high occurrences of Saharan dust intrusions (about 1 day of Saharan dust intrusion every 10 days) has been observed at CNR-IMAA because of the short distance from the Sahara region. During 6 years of observations, very peculiar cases of volcanic aerosol emitted by Etna volcano and aerosol released by large forest fires burning occurred in Alaska and Canada have been observed in the free troposphere at our site. Particular attention is devoted to lidar ratio both for the

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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...

  9. Some Spatial Aspects of Southeastern United States Climatology.

    Science.gov (United States)

    Soule, Peter T.

    1998-01-01

    Focuses on the climatology of an eight-state region in the southern and southeastern United States. Discusses general controls of climate and spatial patterns of various climatic averages. Examines mapped extremes as a means of fostering increased awareness of the variability that exists for climatic conditions in the region. (CMK)

  10. A North American regional reanalysis climatology of the Haines Index

    Science.gov (United States)

    Wei Lu; Joseph J. (Jay) Charney; Sharon Zhong; Xindi Bian; Shuhua. Liu

    2011-01-01

    A warm-season (May through October) Haines Index climatology is derived using 32-km regional reanalysis temperature and humidity data from 1980 to 2007. We compute lapse rates, dewpoint depressions, Haines Index factors A and B, and values for each of the low-, mid- and high-elevation variants of the Haines Index. Statistical techniques are used to investigate the...

  11. A Climatology of Nocturnal Low-Level Jets at Cabauw

    NARCIS (Netherlands)

    Baas, P.; Bosveld, F.C.; Baltink, H.K.; Holtslag, A.A.M.

    2009-01-01

    A climatology of nocturnal low-level jets (LLJs) is presented for the topographically flat measurement site at Cabauw, the Netherlands. LLJ characteristics are derived from a 7-yr half-hourly database of wind speed profiles, obtained from the 200-m mast and a wind profiler. Many LLJs at Cabauw

  12. Are climatological correlations with the Hale double sunspot cycle meaningful

    International Nuclear Information System (INIS)

    Goldberg, R.A.; Herman, J.R.

    1975-09-01

    A sunspot cycle which may have been subject to a predicted phase reversal between 1800 and 1880 A.D. is discussed. Several climatological parameters normally correlated with this cycle are examined and do not exhibit a corresponding phase reversal during this period. It is proposed that this apparent discrepency can be resolved by suitable observations during the upcoming half decade

  13. Climatology and Landfall of Tropical Cyclones in the South- West ...

    African Journals Online (AJOL)

    Abstract—The climatology of cyclone formation and behaviour in the South-West Indian Ocean, including landfall in Mozambique and Madagascar, has been investigated. The records used were obtained by merging track data from the Joint Typhoon Warning Centre with data from La Reunion – Regional Specialised ...

  14. Cluster analysis for validated climatology stations using precipitation in Mexico

    NARCIS (Netherlands)

    Bravo Cabrera, J. L.; Azpra-Romero, E.; Zarraluqui-Such, V.; Gay-García, C.; Estrada Porrúa, F.

    2012-01-01

    Annual average of daily precipitation was used to group climatological stations into clusters using the k-means procedure and principal component analysis with varimax rotation. After a careful selection of the stations deployed in Mexico since 1950, we selected 349 characterized by having 35 to 40

  15. Climatology and trends of summer high temperature days in India ...

    Indian Academy of Sciences (India)

    patterns, there is clear change in climatological mean and coefficient of variation of HT days in a ... regions of India probably from mid 1990s. ... in extreme climate events are more sensitive to cli- ... C since mid-1990s in south, east, north.

  16. 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).

  17. GRACILE: a comprehensive climatology of atmospheric gravity wave parameters based on satellite limb soundings

    Directory of Open Access Journals (Sweden)

    M. Ern

    2018-04-01

    Full Text Available Gravity waves are one of the main drivers of atmospheric dynamics. The spatial resolution of most global atmospheric models, however, is too coarse to properly resolve the small scales of gravity waves, which range from tens to a few thousand kilometers horizontally, and from below 1 km to tens of kilometers vertically. Gravity wave source processes involve even smaller scales. Therefore, general circulation models (GCMs and chemistry climate models (CCMs usually parametrize the effect of gravity waves on the global circulation. These parametrizations are very simplified. For this reason, comparisons with global observations of gravity waves are needed for an improvement of parametrizations and an alleviation of model biases. We present a gravity wave climatology based on atmospheric infrared limb emissions observed by satellite (GRACILE. GRACILE is a global data set of gravity wave distributions observed in the stratosphere and the mesosphere by the infrared limb sounding satellite instruments High Resolution Dynamics Limb Sounder (HIRDLS and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER. Typical distributions (zonal averages and global maps of gravity wave vertical wavelengths and along-track horizontal wavenumbers are provided, as well as gravity wave temperature variances, potential energies and absolute momentum fluxes. This global data set captures the typical seasonal variations of these parameters, as well as their spatial variations. The GRACILE data set is suitable for scientific studies, and it can serve for comparison with other instruments (ground-based, airborne, or other satellite instruments and for comparison with gravity wave distributions, both resolved and parametrized, in GCMs and CCMs. The GRACILE data set is available as supplementary data at https://doi.org/10.1594/PANGAEA.879658.

  18. GRACILE: a comprehensive climatology of atmospheric gravity wave parameters based on satellite limb soundings

    Science.gov (United States)

    Ern, Manfred; Trinh, Quang Thai; Preusse, Peter; Gille, John C.; Mlynczak, Martin G.; Russell, James M., III; Riese, Martin

    2018-04-01

    Gravity waves are one of the main drivers of atmospheric dynamics. The spatial resolution of most global atmospheric models, however, is too coarse to properly resolve the small scales of gravity waves, which range from tens to a few thousand kilometers horizontally, and from below 1 km to tens of kilometers vertically. Gravity wave source processes involve even smaller scales. Therefore, general circulation models (GCMs) and chemistry climate models (CCMs) usually parametrize the effect of gravity waves on the global circulation. These parametrizations are very simplified. For this reason, comparisons with global observations of gravity waves are needed for an improvement of parametrizations and an alleviation of model biases. We present a gravity wave climatology based on atmospheric infrared limb emissions observed by satellite (GRACILE). GRACILE is a global data set of gravity wave distributions observed in the stratosphere and the mesosphere by the infrared limb sounding satellite instruments High Resolution Dynamics Limb Sounder (HIRDLS) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER). Typical distributions (zonal averages and global maps) of gravity wave vertical wavelengths and along-track horizontal wavenumbers are provided, as well as gravity wave temperature variances, potential energies and absolute momentum fluxes. This global data set captures the typical seasonal variations of these parameters, as well as their spatial variations. The GRACILE data set is suitable for scientific studies, and it can serve for comparison with other instruments (ground-based, airborne, or other satellite instruments) and for comparison with gravity wave distributions, both resolved and parametrized, in GCMs and CCMs. The GRACILE data set is available as supplementary data at https://doi.org/10.1594/PANGAEA.879658" target="_blank">https://doi.org/10.1594/PANGAEA.879658.

  19. Reanalysis comparisons of upper tropospheric-lower stratospheric jets and multiple tropopauses

    Science.gov (United States)

    Manney, Gloria L.; Hegglin, Michaela I.; Lawrence, Zachary D.; Wargan, Krzysztof; Millán, Luis F.; Schwartz, Michael J.; Santee, Michelle L.; Lambert, Alyn; Pawson, Steven; Knosp, Brian W.; Fuller, Ryan A.; Daffer, William H.

    2017-09-01

    The representation of upper tropospheric-lower stratospheric (UTLS) jet and tropopause characteristics is compared in five modern high-resolution reanalyses for 1980 through 2014. Climatologies of upper tropospheric jet, subvortex jet (the lowermost part of the stratospheric vortex), and multiple tropopause frequency distributions in MERRA (Modern-Era Retrospective analysis for Research and Applications), ERA-I (ERA-Interim; the European Centre for Medium-Range Weather Forecasts, ECMWF, interim reanalysis), JRA-55 (the Japanese 55-year Reanalysis), and CFSR (the Climate Forecast System Reanalysis) are compared with those in MERRA-2. Differences between alternate products from individual reanalysis systems are assessed; in particular, a comparison of CFSR data on model and pressure levels highlights the importance of vertical grid spacing. Most of the differences in distributions of UTLS jets and multiple tropopauses are consistent with the differences in assimilation model grids and resolution - for example, ERA-I (with coarsest native horizontal resolution) typically shows a significant low bias in upper tropospheric jets with respect to MERRA-2, and JRA-55 (the Japanese 55-year Reanalysis) a more modest one, while CFSR (with finest native horizontal resolution) shows a high bias with respect to MERRA-2 in both upper tropospheric jets and multiple tropopauses. Vertical temperature structure and grid spacing are especially important for multiple tropopause characterizations. Substantial differences between MERRA and MERRA-2 are seen in mid- to high-latitude Southern Hemisphere (SH) winter upper tropospheric jets and multiple tropopauses as well as in the upper tropospheric jets associated with tropical circulations during the solstice seasons; some of the largest differences from the other reanalyses are seen in the same times and places. Very good qualitative agreement among the reanalyses is seen between the large-scale climatological features in UTLS jet and

  20. 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.

  1. 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.

  2. 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 ...

  3. Dimethylsulphide (DMS emissions from the western Pacific Ocean: a potential marine source for stratospheric sulphur?

    Directory of Open Access Journals (Sweden)

    C. A. Marandino

    2013-08-01

    Full Text Available Sea surface and atmospheric measurements of dimethylsulphide (DMS were performed during the TransBrom cruise in the western Pacific Ocean between Japan and Australia in October 2009. Air–sea DMS fluxes were computed between 0 and 30 μmol m−2 d−1, which are in agreement with those computed by the current climatology, and peak emissions of marine DMS into the atmosphere were found during the occurrence of tropical storm systems. Atmospheric variability in DMS, however, did not follow that of the computed fluxes and was more related to atmospheric transport processes. The computed emissions were used as input fields for the Lagrangian dispersion model FLEXPART, which was set up with actual meteorological fields from ERA-Interim data and different chemical lifetimes of DMS. A comparison with aircraft in situ data from the adjacent HIPPO2 campaign revealed an overall good agreement between modelled versus observed DMS profiles over the tropical western Pacific Ocean. Based on observed DMS emissions and meteorological fields along the cruise track, the model projected that up to 30 g S per month in the form of DMS, emitted from an area of 6 × 104 m2, can be transported above 17 km. This surprisingly large DMS entrainment into the stratosphere is disproportionate to the regional extent of the area of emissions and mainly due to the high convective activity in this region as simulated by the transport model. Thus, if DMS can cross the tropical tropopause layer (TTL, we suggest that the considerably larger area of the tropical western Pacific Ocean can be a source of sulphur to the stratosphere, which has not been considered as yet.

  4. Effects of Major Sudden Stratospheric Warmings Identified in Midlatitude Mesospheric Rayleigh-Scatter Lidar Temperatures

    Science.gov (United States)

    Sox, L.; Wickwar, V. B.; Fish, C. S.; Herron, J. P.

    2014-12-01

    Mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions. However, observations of these anomalies at midlatitudes are sparse. The very dense 11-year data set, collected between 1993-2004, with the Rayleigh-scatter lidar at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) at the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU), has been carefully examined for such anomalies. The temperatures derived from these data extend over the mesosphere, from 45 to 90 km. During this period extensive data were acquired during seven major SSW events. In this work we aim to determine the characteristics of the midlatitude mesospheric temperatures during these seven major SSWs. To do this, comparisons were made between the temperature profiles on individual nights before, during, and after the SSW events and the corresponding derived climatological temperature profiles (31-day by 11-year average) for those nights. A consistent disturbance pattern was observed in the mesospheric temperatures during these SSWs. A distinct shift from the nominal winter temperature pattern to a pattern more characteristic of summer temperatures was seen in the midlatitude mesosphere close to when the zonal winds in the polar stratosphere (at 10 hPa, 60° N) reversed from eastward to westward. This shift lasted for several days. This change in pattern included coolings in the upper mesosphere, comparable to those seen in the polar regions, and warmings in the lower mesosphere.

  5. 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.

  6. The modification of the typhoon rainfall climatology model in Taiwan

    Directory of Open Access Journals (Sweden)

    C.-S. Lee

    2013-01-01

    Full Text Available This study is focused on the modification of a typhoon rainfall climatological model, by using the dataset up to 2006 and including data collected from rain gauge stations established after the 921 earthquake (1999. Subsequently, the climatology rainfall models for westward- and northward-moving typhoons are established by using the typhoon track classification from the Central Weather Bureau. These models are also evaluated and examined using dependent cases collected between 1989 and 2006 and independent cases collected from 2007 to 2011. For the dependent cases, the average total rainfall at all rain gauge stations forecasted using the climatology rainfall models for westward- (W-TRCM12 and northward-moving (N-TRCM12 typhoons is superior to that obtained using the original climatological model (TRCM06. Model W-TRCM12 significantly improves the precipitation underestimation of model TRCM06. The independent cases show that model W-TRCM12 provides better accumulated rainfall forecasts and distributions than model TRCM06. A climatological model for accompanied northeastern monsoons (A-TRCM12 for special typhoon types has also been established. The current A-TRCM12 model only contains five historical cases and various typhoon combinations can cause precipitation in different regions. Therefore, precipitation is likely to be significantly overestimated and high false alarm ratios are likely to occur in specific regions. For example, model A-TRCM12 significantly overestimates the rainfall forecast for Typhoon Mitag, an independent case from 2007. However, it has a higher probability of detection than model TRCM06. From a disaster prevention perspective, a high probability of detection is much more important than a high false alarm ratio. The modified models can contribute significantly to operational forecast.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Influence of aerosol particles, clouds, and condensation trails on the climate in Bavaria

    International Nuclear Information System (INIS)

    Wiegner, M.

    1994-01-01

    Human interventions in the climate system occur mainly through the emission of trace gases and aerosol particles. Emissions of aerosol particles can also change the properties of clouds. Climate model calculations have shown that an increase in trace gas concentrations causes the lower atmosphere to warm. According to numerical studies performed during the past few years, anthropogenic aerosol sources can have a cooling effect which is of the same order as the warming caused by greenhouse gases. However, due to their differing time constants and spatial characteristics the two effects are unlikely to neutralise each other over extended regions for any length of time. The currently available models with their very coarse spatial resolution are not suitable for making climatological predictions for Bavaria on the basis of cloud or aerosol properties. What can be done at present is to formulate warnings and propose measures for reducing envir