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

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.

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.

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

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

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.

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.

Odin-OSIRIS stratospheric aerosol data product and SAGE III intercomparison

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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.

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

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.

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

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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.

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.

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.

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

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.

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

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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

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

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

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.

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.

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

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.

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.

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

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.

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

Directory of Open Access Journals (Sweden)

P. J. Popp

2006-01-01

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

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.;

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

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)

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

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.

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.

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

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.

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

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.

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

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

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.

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

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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

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

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.

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.

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.

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

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.

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

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

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.

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.

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

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.

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

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.

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.

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.

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.

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

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.

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).

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.

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.

Aerosols in the tropical and subtropical UT/LS: in-situ measurements of submicron particle abundance and volatility

Directory of Open Access Journals (Sweden)

S. Borrmann

2010-06-01

Full Text Available Processes occurring in the tropical upper troposphere (UT, the Tropical Transition Layer (TTL, and the lower stratosphere (LS are of importance for the global climate, for stratospheric dynamics and air chemistry, and for their influence on the global distribution of water vapour, trace gases and aerosols. In this contribution we present aerosol and trace gas (in-situ measurements from the tropical UT/LS over Southern Brazil, Northern Australia, and West Africa. The instruments were operated on board of the Russian high altitude research aircraft M-55 "Geophysica" and the DLR Falcon-20 during the campaigns TROCCINOX (Araçatuba, Brazil, February 2005, SCOUT-O3 (Darwin, Australia, December 2005, and SCOUT-AMMA (Ouagadougou, Burkina Faso, August 2006. The data cover submicron particle number densities and volatility from the COndensation PArticle counting System (COPAS, as well as relevant trace gases like N₂O, ozone, and CO. We use these trace gas measurements to place the aerosol data into a broader atmospheric context. Also a juxtaposition of the submicron particle data with previous measurements over Costa Rica and other tropical locations between 1999 and 2007 (NASA DC-8 and NASA WB-57F is provided. The submicron particle number densities, as a function of altitude, were found to be remarkably constant in the tropical UT/LS altitude band for the two decades after 1987. Thus, a parameterisation suitable for models can be extracted from these measurements. Compared to the average levels in the period between 1987 and 2007 a slight increase of particle abundances was found for 2005/2006 at altitudes with potential temperatures, Θ, above 430 K. The origins of this increase are unknown except for increases measured during SCOUT-AMMA. Here the eruption of the Soufrière Hills volcano in the Caribbean caused elevated particle mixing ratios. The vertical profiles from Northern hemispheric mid-latitudes between 1999 and 2006 also are

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.

Optical properties and microphysical characterization of single levitated aerosol particles. Final report; Optische Eigenschaften und mikrophysikalische Charakterisierung von einzeln levitierten Aerosolpartikeln. Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Leisner, T.; Vortisch, H.

2002-07-01

Composition, micro structure and phase of the sulfate aerosol particles in the stratosphere are crucial for their activity in the polar stratospheric ozone depletion and not well known until now. We have performed Raman spectroscopic laboratory investigations with model particles levitated in an electrodynamic balance under stratospheric conditions. We were able to obtain new results on the dynamics of phase transitions in such particles and on the type of metastable structures encountered after the freezing of heavily supercooled sulfuric acid solution. The compositions found were usually not consistent with the phase diagram. Sulfuric acid tetrahydrate was the dominant compound even when dilute solution nucleated. It was formed crystalline not immediately after nucleation but only when the particles approached the melting point. At lower temperatures a nanocrystalline and strongly disordered hydrate was observed. Our investigations help to arrive at a better understanding of the role of the sulfuric acid aerosol in stratospheric chemistry. (orig.) [German] Zusammensetzung, Mikrostruktur und Aggregatzustand der stratosphaerischen Schwefelsaeureaerosole bestimmen deren Aktivitaet im polaren Ozonabbau und sind bislang kaum erforscht. Unsere ramanspektroskopischen Laboruntersuchungen an Modellpartikeln in einem elektrodynamischen Levitator konnten hier neue Erkenntnisse zur Dynamik von Phasenumwandlungen sowie der Struktur metastabiler Zustaende liefern. Insbesondere wurden stark vom Phasendiagramm abweichende Zusammensetzungen als typisch erkannt. So konnte Schwefelsaeuretetrahydrat als das dominierende Hydrat bei der Nukleation auch verduennter Schwefelsaeureloesungen erkannt werden. Es bildet sich kritallin jedoch nicht direkt beim Gefrieren unterkuehlter Schwefelsaeureloesungen, sondern erst bei deren Annaeherung an den Schmelzpunkt. Vorher liegt ein nanokristallines und stark ungeordnetes Hydrat vor. Durch derartige Untersuchungen wird ein besseres Verstaendnis

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

MIPAS detection of cloud and aerosol particle occurrence in the UTLS with comparison to HIRDLS and CALIOP

Directory of Open Access Journals (Sweden)

H. Sembhi

2012-10-01

Full Text Available Satellite infrared emission instruments require efficient systems that can separate and flag observations which are affected by clouds and aerosols. This paper investigates the identification of cloud and aerosols from infrared, limb sounding spectra that were recorded by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS, a high spectral resolution Fourier transform spectrometer on the European Space Agency's (ESA ENVISAT (Now inoperative since April 2012 due to loss of contact. Specifically, the performance of an existing cloud and aerosol particle detection method is simulated with a radiative transfer model in order to establish, for the first time, confident detection limits for particle presence in the atmosphere from MIPAS data. The newly established thresholds improve confidence in the ability to detect particle injection events, plume transport in the upper troposphere and lower stratosphere (UTLS and better characterise cloud distributions utilising MIPAS spectra. The method also provides a fast front-end detection system for the MIPClouds processor; a processor designed for the retrieval of macro- and microphysical cloud properties from the MIPAS data.

It is shown that across much of the stratosphere, the threshold for the standard cloud index in band A is 5.0 although threshold values of over 6.0 occur in restricted regimes. Polar regions show a surprising degree of uncertainty at altitudes above 20 km, potentially due to changing stratospheric trace gas concentrations in polar vortex conditions and poor signal-to-noise due to cold atmospheric temperatures. The optimised thresholds of this study can be used for much of the time, but time/composition-dependent thresholds are recommended for MIPAS data for the strongly perturbed polar stratosphere. In the UT, a threshold of 5.0 applies at 12 km and above but decreases rapidly at lower altitudes. The new thresholds are shown to allow much more sensitive

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.

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.

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.

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.

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.

Interactions of meteoric smoke particles with sulphuric acid in the Earth's stratosphere

Directory of Open Access Journals (Sweden)

R. W. Saunders

2012-05-01

Full Text Available Nano-sized meteoric smoke particles (MSPs with iron-magnesium silicate compositions, formed in the upper mesosphere as a result of meteoric ablation, may remove sulphuric acid from the gas-phase above 40 km and may also affect the composition and behaviour of supercooled H₂SO₄-H₂O droplets in the global stratospheric aerosol (Junge layer.

This study describes a time-resolved spectroscopic analysis of the evolution of the ferric (Fe³⁺ ion originating from amorphous ferrous (Fe²⁺-based silicate powders dissolved in varying Wt % sulphuric acid (30–75 % solutions over a temperature range of 223–295 K. Complete dissolution of the particles was observed under all conditions. The first-order rate coefficient for dissolution decreases at higher Wt % and lower temperature, which is consistent with the increased solution viscosity limiting diffusion of H₂SO₄ to the particle surfaces. Dissolution under stratospheric conditions should take less than a week, and is much faster than the dissolution of crystalline Fe²⁺ compounds.

The chemistry climate model UMSLIMCAT (based on the UKMO Unified Model was then used to study the transport of MSPs through the middle atmosphere. A series of model experiments were performed with different uptake coefficients. Setting the concentration of 1.5 nm radius MSPs at 80 km to 3000 cm⁻³ (based on rocket-borne charged particle measurements, the model matches the reported Wt % Fe values of 0.5–1.0 in Junge layer sulphate particles, and the MSP optical extinction between 40 and 75 km measured by a satellite-borne spectrometer, if the global meteoric input rate is about 20 tonnes per day. The model indicates that an uptake coefficient ≥0.01 is required to account for the observed two orders of magnitude depletion of H₂SO₄ vapour above 40 km.

Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in situ and satellite observations

Science.gov (United States)

Lurton, Thibaut; Jégou, Fabrice; Berthet, Gwenaël; Renard, Jean-Baptiste; Clarisse, Lieven; Schmidt, Anja; Brogniez, Colette; Roberts, Tjarda J.

2018-03-01

Volcanic eruptions impact climate through the injection of sulfur dioxide (SO2), which is oxidized to form sulfuric acid aerosol particles that can enhance the stratospheric aerosol optical depth (SAOD). Besides large-magnitude eruptions, moderate-magnitude eruptions such as Kasatochi in 2008 and Sarychev Peak in 2009 can have a significant impact on stratospheric aerosol and hence climate. However, uncertainties remain in quantifying the atmospheric and climatic impacts of the 2009 Sarychev Peak eruption due to limitations in previous model representations of volcanic aerosol microphysics and particle size, whilst biases have been identified in satellite estimates of post-eruption SAOD. In addition, the 2009 Sarychev Peak eruption co-injected hydrogen chloride (HCl) alongside SO2, whose potential stratospheric chemistry impacts have not been investigated to date. We present a study of the stratospheric SO2-particle-HCl processing and impacts following Sarychev Peak eruption, using the Community Earth System Model version 1.0 (CESM1) Whole Atmosphere Community Climate Model (WACCM) - Community Aerosol and Radiation Model for Atmospheres (CARMA) sectional aerosol microphysics model (with no a priori assumption on particle size). The Sarychev Peak 2009 eruption injected 0.9 Tg of SO2 into the upper troposphere and lower stratosphere (UTLS), enhancing the aerosol load in the Northern Hemisphere. The post-eruption evolution of the volcanic SO2 in space and time are well reproduced by the model when compared to Infrared Atmospheric Sounding Interferometer (IASI) satellite data. Co-injection of 27 Gg HCl causes a lengthening of the SO2 lifetime and a slight delay in the formation of aerosols, and acts to enhance the destruction of stratospheric ozone and mono-nitrogen oxides (NOx) compared to the simulation with volcanic SO2 only. We therefore highlight the need to account for volcanic halogen chemistry when simulating the impact of eruptions such as Sarychev on

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

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

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

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.)

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.

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.

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.

The Impact of Aerosol Particle Mixing State on the Hygroscopicity of Sea Spray Aerosol.

Science.gov (United States)

Schill, Steven R; Collins, Douglas B; Lee, Christopher; Morris, Holly S; Novak, Gordon A; Prather, Kimberly A; Quinn, Patricia K; Sultana, Camille M; Tivanski, Alexei V; Zimmermann, Kathryn; Cappa, Christopher D; Bertram, Timothy H

2015-06-24

Aerosol particles influence global climate by determining cloud droplet number concentrations, brightness, and lifetime. Primary aerosol particles, such as those produced from breaking waves in the ocean, display large particle-particle variability in chemical composition, morphology, and physical phase state, all of which affect the ability of individual particles to accommodate water and grow into cloud droplets. Despite such diversity in molecular composition, there is a paucity of methods available to assess how particle-particle variability in chemistry translates to corresponding differences in aerosol hygroscopicity. Here, an approach has been developed that allows for characterization of the distribution of aerosol hygroscopicity within a chemically complex population of atmospheric particles. This methodology, when applied to the interpretation of nascent sea spray aerosol, provides a quantitative framework for connecting results obtained using molecular mimics generated in the laboratory with chemically complex ambient aerosol. We show that nascent sea spray aerosol, generated in situ in the Atlantic Ocean, displays a broad distribution of particle hygroscopicities, indicative of a correspondingly broad distribution of particle chemical compositions. Molecular mimics of sea spray aerosol organic material were used in the laboratory to assess the volume fractions and molecular functionality required to suppress sea spray aerosol hygroscopicity to the extent indicated by field observations. We show that proper accounting for the distribution and diversity in particle hygroscopicity and composition are important to the assessment of particle impacts on clouds and global climate.

Size-specific composition of aerosols in the El Chichon volcanic cloud

Science.gov (United States)

Woods, D. C.; Chuan, R. L.

1983-01-01

A NASA U-2 research aircraft flew sampling missions in April, May, July, November, and December 1982 aimed at obtaining in situ data in the stratospheric cloud produced from the March-April 1982 El Chichon eruptions. Post flight analyses provided information on the aerosol composition and morphology. The particles ranged in size from smaller than 0.05 m to larger than 20 m diameter and were quite complex in composition. In the April, May, and July samples the aerosol mass was dominated by magmatic and lithic particles larger than about 3 m. The submicron particles consisted largely of sulfuric acid. Halite particles, believed to be related to a salt dome beneath El Chichon, were collected in the stratosphere in April and May. On the July 23 flight, copper-zinc oxide particles were collected. In July, November, and December, in addition to the volcanic ash and acid particles, carbon-rich particles smaller than about 0.1 m aerodynamic diameter were abundant.

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.

PIXE analysis of atmospheric aerosol and hydrometeor particles

International Nuclear Information System (INIS)

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

1993-01-01

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

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.

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

Workplace aerosol mass concentration measurement using optical particle counters.

Science.gov (United States)

Görner, Peter; Simon, Xavier; Bémer, Denis; Lidén, Göran

2012-02-01

Direct-reading aerosol measurement usually uses the optical properties of airborne particles to detect and measure particle concentration. In the case of occupational hygiene, mass concentration measurement is often required. Two aerosol monitoring methods are based on the principle of light scattering: optical particle counting (OPC) and photometry. The former analyses the light scattered by a single particle, the latter by a cloud of particles. Both methods need calibration to transform the quantity of scattered light detected into particle concentration. Photometers are simpler to use and can be directly calibrated to measure mass concentration. However, their response varies not only with aerosol concentration but also with particle size distribution, which frequently contributes to biased measurement. Optical particle counters directly measure the particle number concentration and particle size that allows assessment of the particle mass provided the particles are spherical and of known density. An integrating algorithm is used to calculate the mass concentration of any conventional health-related aerosol fraction. The concentrations calculated thus have been compared with simultaneous measurements by conventional gravimetric sampling to check the possibility of field OPC calibration with real workplace aerosols with a view to further monitoring particle mass concentration. Aerosol concentrations were measured in the food industry using the OPC GRIMM® 1.108 and the CIP 10-Inhalable and CIP 10-Respirable (ARELCO®) aerosol samplers while meat sausages were being brushed and coated with calcium carbonate. Previously, the original OPC inlet had been adapted to sample inhalable aerosol. A mixed aerosol of calcium carbonate and fungi spores was present in the workplace. The OPC particle-size distribution and an estimated average particle density of both aerosol components were used to calculate the mass concentration. The inhalable and respirable aerosol fractions

Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in situ and satellite observations

Directory of Open Access Journals (Sweden)

T. Lurton

2018-03-01

Full Text Available Volcanic eruptions impact climate through the injection of sulfur dioxide (SO2, which is oxidized to form sulfuric acid aerosol particles that can enhance the stratospheric aerosol optical depth (SAOD. Besides large-magnitude eruptions, moderate-magnitude eruptions such as Kasatochi in 2008 and Sarychev Peak in 2009 can have a significant impact on stratospheric aerosol and hence climate. However, uncertainties remain in quantifying the atmospheric and climatic impacts of the 2009 Sarychev Peak eruption due to limitations in previous model representations of volcanic aerosol microphysics and particle size, whilst biases have been identified in satellite estimates of post-eruption SAOD. In addition, the 2009 Sarychev Peak eruption co-injected hydrogen chloride (HCl alongside SO2, whose potential stratospheric chemistry impacts have not been investigated to date. We present a study of the stratospheric SO2–particle–HCl processing and impacts following Sarychev Peak eruption, using the Community Earth System Model version 1.0 (CESM1 Whole Atmosphere Community Climate Model (WACCM – Community Aerosol and Radiation Model for Atmospheres (CARMA sectional aerosol microphysics model (with no a priori assumption on particle size. The Sarychev Peak 2009 eruption injected 0.9 Tg of SO2 into the upper troposphere and lower stratosphere (UTLS, enhancing the aerosol load in the Northern Hemisphere. The post-eruption evolution of the volcanic SO2 in space and time are well reproduced by the model when compared to Infrared Atmospheric Sounding Interferometer (IASI satellite data. Co-injection of 27 Gg HCl causes a lengthening of the SO2 lifetime and a slight delay in the formation of aerosols, and acts to enhance the destruction of stratospheric ozone and mono-nitrogen oxides (NOx compared to the simulation with volcanic SO2 only. We therefore highlight the need to account for volcanic halogen chemistry when simulating the impact of eruptions

Dynamics of neutral and charged aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Leppae, J.

2012-07-01

Atmospheric aerosol particles have various climate effects and adverse health effects, which both depend on the size and number concentration of the particles. Freshly-formed particles are not large enough to impact neither health nor climate and they are most susceptible to removal by collisions with larger pre-existing particles. Consequently, the knowledge of both the formation and the growth rate of particles are crucially important when assessing the health and climate effects of atmospheric new particle formation. The purpose of this thesis is to increase our knowledge of the dynamics of neutral and charged aerosol particles with a specific interest towards the particle growth rate and processes affecting the aerosol charging state. A new model, Ion-UHMA, which simulates the dynamics of neutral and charged particles, was developed for this purpose. Simple analytical formulae that can be used to estimate the growth rate due to various processes were derived and used to study the effects of charged particles on the growth rate. It was found that the growth rate of a freshly-formed particle population due to condensation and coagulation could be significantly increased when a considerable fraction of the particles are charged. Finally, recent data-analysis methods that have been applied to the aerosol charging states obtained from the measurements were modified for a charge asymmetric framework. The methods were then tested on data obtained from aerosol dynamics simulations. The methods were found to be able to provide reasonable estimates on the growth rate and proportion of particles formed via ion-induced nucleation, provided that the growth rate is high enough and that the charged particles do not grow much more rapidly than the neutral ones. A simple procedure for estimating whether the methods are suitable for analysing data obtained in specific conditions was provided. In this thesis, the dynamics of neutral and charged aerosol particles were studied in

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.)

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.

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.

The hygroscopicity of indoor aerosol particles

International Nuclear Information System (INIS)

Wei, L.

1993-07-01

A system to study the hygroscopic growth of particle was developed by combining a Tandem Differential Mobility Analyzer (TDMA) with a wetted wall reactor. This system is capable of mimicking the conditions in human respiratory tract, and measuring the particle size change due to the hygroscopic growth. The performance of the system was tested with three kinds of particles of known composition, NaCl, (NH 4 ) 2 SO 4 , and (NH 4 )HS0 4 particles. The hygroscopicity of a variety of common indoor aerosol particles was studied including combustion aerosols (cigarette smoking, cooking, incenses and candles) and consumer spray products such as glass cleaner, general purpose cleaner, hair spray, furniture polish spray, disinfectant, and insect killer. Experiments indicate that most of the indoor aerosols show some hygroscopic growth and only a few materials do not. The magnitude of hygroscopic growth ranges from 20% to 300% depending on the particle size and fraction of water soluble components

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.

Climate impact of idealized winter polar mesospheric and stratospheric ozone losses as caused by energetic particle precipitation

Science.gov (United States)

Meraner, Katharina; Schmidt, Hauke

2018-01-01

Energetic particles enter the polar atmosphere and enhance the production of nitrogen oxides and hydrogen oxides in the winter stratosphere and mesosphere. Both components are powerful ozone destroyers. Recently, it has been inferred from observations that the direct effect of energetic particle precipitation (EPP) causes significant long-term mesospheric ozone variability. Satellites observe a decrease in mesospheric ozone up to 34 % between EPP maximum and EPP minimum. Stratospheric ozone decreases due to the indirect effect of EPP by about 10-15 % observed by satellite instruments. Here, we analyze the climate impact of winter boreal idealized polar mesospheric and polar stratospheric ozone losses as caused by EPP in the coupled Max Planck Institute Earth System Model (MPI-ESM). Using radiative transfer modeling, we find that the radiative forcing of mesospheric ozone loss during polar night is small. Hence, climate effects of mesospheric ozone loss due to energetic particles seem unlikely. Stratospheric ozone loss due to energetic particles warms the winter polar stratosphere and subsequently weakens the polar vortex. However, those changes are small, and few statistically significant changes in surface climate are found.

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

Formation and dynamic change of aerosol particles

International Nuclear Information System (INIS)

Kasahara, Mikio

1986-01-01

Processes of aerosol particle nucleation are roughly grouped into two types. In one, aerosol is produced as a result of dispersion of solid or liquid by mechanical force while in the other it is formed through phase transition from gas to solid or liquid due to cohesion caused by cooling, expansion or chemical reaction. This article reviews various aspects of aerosol particle nucleation through the latter type of processes and behaviors of the particles formed. Gas-to-particle conversion processes are divided into those of homogeneous and heterogeneous nucleation, and the former include homogeneous homomolecular and homogeneous heteromolecular nucleation processes. Here, homoneneous homomolecular nucleation is described centering on the theories proposed by Backer and Doring-Zeldovich-Volmer-Frenkel while homogeneous heteromolecular systems are outlined citing the theory developed by Kiang and Stauffer. Heterogeneous nucleation (or heterogeneous condensation) is discussed on the basis of the relationship between the mean free path of air molecules and the particle size. Various theories for particle formation and growth are listed and briefly outlined. Some of them are compared with experimental results. Models are cited to explain behaviors of aerosol particles after being formed. Also described is simulation of particle nucleation and growth in relation to atmospheric pollution and possible accidents of liquid-metal fast breeder reactors. (Nogami, K.)

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

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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.

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

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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.

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

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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.

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

International Nuclear Information System (INIS)

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

2006-01-01

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

Labeling suspended aerosol particles with short-lived radionuclides for determination of particle deposition

International Nuclear Information System (INIS)

Smith, M.F.; Bryant, S.; Welch, S.; Digenis, G.A.

1984-01-01

Radiotracer techniques were developed to examine parameters that characterize pressurized aerosols designed to deliver insoluble particles suspended in the aerosol formulation. Microaggregated bovine serum albumin microspheres that were to be suspended were labeled with iodine-131 (t1/2 . 8 d). This iodination procedure (greater than 80% effective) is also applicable to iodine-123, which possesses superior characteristics for external imaging and further in vivo studies. This report shows that for pressurized aerosols containing suspended particles, each metered dose is approximately equal (not including the priming doses and the emptying doses). Increase in the delivery of the albumin particles out of the canister was best achieved by pretreating the valve assembly with a solution of 2% (w/v) bovine serum albumin in phosphate buffer. Use of a cascade impactor delineated the particle size distribution of the micropheres, with the majority of particles ranging in size from 2 to 8 microns. The data disclosed here indicate that the techniques developed with short-lived radionuclides can be used to quantitate each metered dose, characterize the particle size distribution profile of the aerosol contents, and determine the extent of deposition of the particles in the aerosol canister and all of its components

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.

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.

Climate impact of idealized winter polar mesospheric and stratospheric ozone losses as caused by energetic particle precipitation

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K. Meraner

2018-01-01

Full Text Available Energetic particles enter the polar atmosphere and enhance the production of nitrogen oxides and hydrogen oxides in the winter stratosphere and mesosphere. Both components are powerful ozone destroyers. Recently, it has been inferred from observations that the direct effect of energetic particle precipitation (EPP causes significant long-term mesospheric ozone variability. Satellites observe a decrease in mesospheric ozone up to 34 % between EPP maximum and EPP minimum. Stratospheric ozone decreases due to the indirect effect of EPP by about 10–15 % observed by satellite instruments. Here, we analyze the climate impact of winter boreal idealized polar mesospheric and polar stratospheric ozone losses as caused by EPP in the coupled Max Planck Institute Earth System Model (MPI-ESM. Using radiative transfer modeling, we find that the radiative forcing of mesospheric ozone loss during polar night is small. Hence, climate effects of mesospheric ozone loss due to energetic particles seem unlikely. Stratospheric ozone loss due to energetic particles warms the winter polar stratosphere and subsequently weakens the polar vortex. However, those changes are small, and few statistically significant changes in surface climate are found.

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.

Continuous air monitor for alpha-emitting aerosol particles

International Nuclear Information System (INIS)

McFarland, A.R.; Ortiz, C.A.; Rodgers, J.C.; Nelson, D.C.

1991-01-01

A new alpha continuous air monitor (CAM) sampler is being developed for use in detecting the presence of alpha-emitting aerosol particles. The effort involves design, fabrication and evaluation of systems for the collection of aerosol and for the processing of data to speciate and quantify the alpha emitters of the interest. At the present time the authors have a prototype of the aerosol sampling system and they have performed wind tunnel tests to characterize the performance of the device for different particle sizes, wind speeds, flow rates and internal design parameters. The results presented herein deal with the aerosol sampling aspects of the new CAM sampler. Wind tunnel tests show that ≥ 50% of 10 μm aerodynamic equivalent diameter (AED) particles penetrate the flow system from the ambient air to the collection filter when the flow rate is 57 L/min (2 cfm) and the wind speed is 1 m/s. The coefficient of variation of deposits of 10 μm AED aerosol particles on the collection filter is 7%. An inlet fractionator for removing high mobility background aerosol particles has been designed and successfully tested. The results show that it is possible to strip 95% of freshly formed radon daughters and 33% of partially aged radon daughters from the aerosol sample. This approach offers the opportunity to improve the signal-to-noise ratio in the alpha energy spectrum region of interest thereby enhancing the performance of background compensation algorithms

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.

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

Laboratory Experiments and Instrument Intercomparison Studies of Carbonaceous Aerosol Particles

Energy Technology Data Exchange (ETDEWEB)

Davidovits, Paul [Boston College, Chestnut Hill, MA (United States)

2015-10-20

Aerosols containing black carbon (and some specific types of organic particulate matter) directly absorb incoming light, heating the atmosphere. In addition, all aerosol particles backscatter solar light, leading to a net-cooling effect. Indirect effects involve hydrophilic aerosols, which serve as cloud condensation nuclei (CCN) that affect cloud cover and cloud stability, impacting both atmospheric radiation balance and precipitation patterns. At night, all clouds produce local warming, but overall clouds exert a net-cooling effect on the Earth. The effect of aerosol radiative forcing on climate may be as large as that of the greenhouse gases, but predominantly opposite in sign and much more uncertain. The uncertainties in the representation of aerosol interactions in climate models makes it problematic to use model projections to guide energy policy. The objective of our program is to reduce the uncertainties in the aerosol radiative forcing in the two areas highlighted in the ASR Science and Program Plan. That is, (1) addressing the direct effect by correlating particle chemistry and morphology with particle optical properties (i.e. absorption, scattering, extinction), and (2) addressing the indirect effect by correlating particle hygroscopicity and CCN activity with particle size, chemistry, and morphology. In this connection we are systematically studying particle formation, oxidation, and the effects of particle coating. The work is specifically focused on carbonaceous particles where the uncertainties in the climate relevant properties are the highest. The ongoing work consists of laboratory experiments and related instrument inter-comparison studies both coordinated with field and modeling studies, with the aim of providing reliable data to represent aerosol processes in climate models. The work is performed in the aerosol laboratory at Boston College. At the center of our laboratory setup are two main sources for the production of aerosol particles: (a

Biomass burning plumes and the aging of black carbon aerosols in the tropopause region observed with the CARIBIC single particle soot photometer

Science.gov (United States)

Ditas, J.; Ma, N.; Zhang, Y.; Assmann, D. N.; Neumaier, M.; Wang, S.; Wang, J.; Zahn, A.; Hermann, M.; Brenninkmeijer, C. A. M.; Poeschl, U.; Su, H.; Cheng, Y.

2017-12-01

Biomass burning (BB) events can release large amounts of refractory black carbon (rBC) into the upper troposphere and lowermost stratosphere (UT/LMS) (Dahlkötter et al., 2014). To explore this effect, a Single Particle Soot Photometer (SP2) was added to the scientific payload of the instrumented CARIBIC container that is installed monthly in the cargo bay of a passenger aircraft (the IAGOS-CARIBIC atmospheric observatory, www.iagos.org). Regular measurement flights with different destinations are performed, covering an area of about 120°W to 120°E and 75°N to 30°S. A wide range of in situ measurements (CO, O3, greenhouse gases, aerosol particles and volatile organic compounds) is combined with a collection of air and aerosol samples for laboratory analyses. Since August 2014, the SP2 measures BC number and mass concentration at altitudes between 8 and 12 km. More than 600 BC measurement hours show a strong impact of BB emissions on the lowermost stratosphere. The BB plumes are identified with the help of concurrent carbon monoxide and acetonitrile measurements showing substantially increased concentrations compared to their background level. Transported into the lowermost stratosphere, BB smoke can be transported over long distances and the BC particles can stay in the atmosphere up to one year. The monthly missions of four consecutive CARIBIC flights sometimes enable to revisit a certain air mass, as was the case during a measurement flight to San Francisco in August 2014, with a stopover time of 2h. The revisited biomass burning plume located over the Altlantic ocean near Greenland was traced back by backward and forward trajectories to open fires in Canada (upper Fig.). The transit time of the smoke plume was estimated to 16 - 19h which perfectly matches our flight time difference ( 18h). Based on the LEO-fit method (Leading Edge Only fit) from Gao et al. (2007), the mixing state of the BC particles within the BB plume was calculated. Our unique data set

Microphysical processing of aerosol particles in orographic clouds

Science.gov (United States)

Pousse-Nottelmann, S.; Zubler, E. M.; Lohmann, U.

2015-08-01

An explicit and detailed treatment of cloud-borne particles allowing for the consideration of aerosol cycling in clouds has been implemented into COSMO-Model, the regional weather forecast and climate model of the Consortium for Small-scale Modeling (COSMO). The effects of aerosol scavenging, cloud microphysical processing and regeneration upon cloud evaporation on the aerosol population and on subsequent cloud formation are investigated. For this, two-dimensional idealized simulations of moist flow over two bell-shaped mountains were carried out varying the treatment of aerosol scavenging and regeneration processes for a warm-phase and a mixed-phase orographic cloud. The results allowed us to identify different aerosol cycling mechanisms. In the simulated non-precipitating warm-phase cloud, aerosol mass is incorporated into cloud droplets by activation scavenging and released back to the atmosphere upon cloud droplet evaporation. In the mixed-phase cloud, a first cycle comprises cloud droplet activation and evaporation via the Wegener-Bergeron-Findeisen (WBF) process. A second cycle includes below-cloud scavenging by precipitating snow particles and snow sublimation and is connected to the first cycle via the riming process which transfers aerosol mass from cloud droplets to snowflakes. In the simulated mixed-phase cloud, only a negligible part of the total aerosol mass is incorporated into ice crystals. Sedimenting snowflakes reaching the surface remove aerosol mass from the atmosphere. The results show that aerosol processing and regeneration lead to a vertical redistribution of aerosol mass and number. Thereby, the processes impact the total aerosol number and mass and additionally alter the shape of the aerosol size distributions by enhancing the internally mixed/soluble Aitken and accumulation mode and generating coarse-mode particles. Concerning subsequent cloud formation at the second mountain, accounting for aerosol processing and regeneration increases

Filter-based Aerosol Measurement Experiments using Spherical Aerosol Particles under High Temperature and High Pressure

Energy Technology Data Exchange (ETDEWEB)

Lee, Jong Chan; Jung, Woo Young; Lee, Hyun Chul; Lee, Doo Young [FNC TECH., Yongin (Korea, Republic of)

2016-05-15

Optical Particle Counter (OPC) is used to provide real-time measurement of aerosol concentration and size distribution. Glass fiber membrane filter also be used to measure average mass concentration. Three tests (MTA-1, 2 and 3) have been conducted to study thermal-hydraulic effect, a filtering tendency at given SiO{sub 2} particles. Based on the experimental results, the experiment will be carried out further with a main carrier gas of steam and different aerosol size. The test results will provide representative behavior of the aerosols under various conditions. The aim of the tests, MTA 1, 2 and 3, are to be able to 1) establish the test manuals for aerosol generation, mixing, sampling and measurement system, which defines aerosol preparation, calibration, operating and evaluation method under high pressure and high temperature 2) develop commercial aerosol test modules applicable to the thermal power plant, environmental industry, automobile exhaust gas, chemical plant, HVAC system including nuclear power plant. Based on the test results, sampled aerosol particles in the filter indicate that important parameters affecting aerosol behavior aerosols are 1) system temperature to keep above a evaporation temperature of ethanol and 2) aerosol losses due to the settling by ethanol liquid droplet.

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.

Single particle composition measurements of artificial Calcium Carbonate aerosols

Science.gov (United States)

Zorn, S. R.; Mentel, T. F.; Schwinger, T.; Croteau, P. L.; Jayne, J.; Worsnop, D. R.; Trimborn, A.

2012-12-01

Mineral dust, with an estimated total source from natural and anthropogenic emissions of up to 2800 Tg/yr, is one of the two largest contributors to total aerosol mass, with only Sea salt having a similar source strength (up to 2600 Tg/yr). The composition of dust particles varies strongly depending on the production process and, most importantly, the source location. Therefore, the composition of single dust particles can be used both to trace source regions of air masses as well as to identify chemical aging processes. Here we present results of laboratory studies on generating artificial calcium carbonate (CaCO3) particles, a model compound for carbonaceous mineral dust particles. Particles were generated by atomizing an aqueous hydrogen carbonate solution. Water was removed using a silica diffusion dryer., then the particles were processed in an oven at temperatures up to 900°C, converting the hydrogen carbonate to its anhydrous form. The resulting aerosol was analyzed using an on-line single particle laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF). The results confirm the conversion to calcium carbonate, and validate that the produced particles indeed can be used as a model compound for carbonaceous dust aerosols.

Nuclear track radiography of 'hot' aerosol particles

International Nuclear Information System (INIS)

Boulyga, S.F.; Kievitskaja, A.I.; Kievets, M.K.; Lomonosova, E.M.; Zhuk, I.V.; Yaroshevich, O.I.; Perelygin, V.P.; Petrova, R.; Brandt, R.; Vater, P.

1999-01-01

Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the α-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (γ,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by 235 U, 239 Pu and 241 Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10 -6 Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical image of the SSNTD surface obtained through a video camera and the determination of size and activity of 'hot' particles

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.

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.

Electrospray ionizer for mass spectrometry of aerosol particles

Science.gov (United States)

He, Siqin; Hogan, Chris; Li, Lin; Liu, Benjamin Y. H.; Naqwi, Amir; Romay, Francisco

2017-09-19

A device and method are disclosed to apply ESI-based mass spectroscopy to submicrometer and nanometer scale aerosol particles. Unipolar ionization is utilized to charge the particles in order to collect them electrostatically on the tip of a tungsten rod. Subsequently, the species composing the collected particles are dissolved by making a liquid flow over the tungsten rod. This liquid with dissolved aerosol contents is formed into highly charged droplets, which release unfragmented ions for mass spectroscopy, such as time-of-flight mass spectroscopy. The device is configured to operate in a switching mode, wherein aerosol deposition occurs while solvent delivery is turned off and vice versa.

Can Condensing Organic Aerosols Lead to Less Cloud Particles?

Science.gov (United States)

Gao, C. Y.; Tsigaridis, K.; Bauer, S.

2017-12-01

We examined the impact of condensing organic aerosols on activated cloud number concentration in a new aerosol microphysics box model, MATRIX-VBS. The model includes the volatility-basis set (VBS) framework in an aerosol microphysical scheme MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) that resolves aerosol mass and number concentrations and aerosol mixing state. Preliminary results show that by including the condensation of organic aerosols, the new model (MATRIX-VBS) has less activated particles compared to the original model (MATRIX), which treats organic aerosols as non-volatile. Parameters such as aerosol chemical composition, mass and number concentrations, and particle sizes which affect activated cloud number concentration are thoroughly evaluated via a suite of Monte-Carlo simulations. The Monte-Carlo simulations also provide information on which climate-relevant parameters play a critical role in the aerosol evolution in the atmosphere. This study also helps simplifying the newly developed box model which will soon be implemented in the global model GISS ModelE as a module.

The attachment of radon daughters to submicron aerosol particles

International Nuclear Information System (INIS)

Grenier, M.G.; Bigu, J.

1984-04-01

A study of the effects of aerosol concentration, aerosol size distribution and relative humidity on the Working Level and the radon daughter concentration was conducted in a 3000 L radon environmental chamber. Typical values of the aerosol concentration varied in the 1 x 10 3 particles/cm 3 to 4.5 x 10 5 particles/cm 3 range. Various size distributions of aerosols that have mean diffusional aerodynamic diameters of .025 μm, .045 μm and .090 μm were tested. A good correlation was found between the Working Level and the aerosol concentration as well as the relative humidity. Most of the activity seems to be associated with particles of diameter between .05 μm and .2 μm. The results presented here are in agreement with work done by other investigators in the health physics field

Single-particle characterization of the high-Arctic summertime aerosol

Science.gov (United States)

Sierau, B.; Chang, R. Y.-W.; Leck, C.; Paatero, J.; Lohmann, U.

2014-07-01

Single-particle mass-spectrometric measurements were carried out in the high Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS). The instrument deployed was an aerosol time-of-flight mass spectrometer (ATOFMS) that provides information on the chemical composition of individual particles and their mixing state in real time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 and 3000 nm in diameter showed mass-spectrometric patterns, indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the high Arctic. To assess the importance of long-range particle sources for aerosol-cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest the presence of a particle type of unknown composition

Single-particle characterization of the High Arctic summertime aerosol

Science.gov (United States)

Sierau, B.; Chang, R. Y.-W.; Leck, C.; Paatero, J.; Lohmann, U.

2014-01-01

Single-particle mass spectrometric measurements were carried out in the High Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS). The instrument deployed was an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) that provides information on the chemical composition of individual particles and their mixing state in real-time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 nm to 3000 nm in diameter showed mass spectrometric patterns indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the High Arctic. To assess the importance of long-range particle sources for aerosol-cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a~minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest a presence of a particle type of unknown composition

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

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.

Single-particle Analyses of Compositions, Morphology, and Viscosity of Aerosol Particles Collected During GoAmazon2014

Science.gov (United States)

Adachi, K.; Gong, Z.; Bateman, A. P.; Martin, S. T.; Cirino, G. G.; Artaxo, P.; Sedlacek, A. J., III; Buseck, P. R.

2014-12-01

Single-particle analysis using transmission electron microscopy (TEM) shows composition and morphology of individual aerosol particles collected during the GoAmazon2014 campaign. These TEM results indicate aerosol types and mixing states, both of which are important for evaluating particle optical properties and cloud condensation nuclei activity. The samples were collected at the T3 site, which is located in the Amazon forest with influences from the urban pollution plume from Manaus. Samples were also collected from the T0 site, which is in the middle of the jungle with minimal to no influences of anthropogenic sources. The aerosol particles mainly originated from 1) anthropogenic pollution (e.g., nanosphere soot, sulfate), 2) biogenic emissions (e.g., primary biogenic particles, organic aerosols), and 3) long-range transport (e.g., sea salts). We found that the biogenic organic aerosol particles contain homogeneously distributed potassium. Particle viscosity is important for evaluating gas-particle interactions and atmospheric chemistry for the particles. Viscosity can be estimated from the rebounding behavior at controlled relative humidities, i.e., highly viscous particles display less rebound on a plate than low-viscosity particles. We collected 1) aerosol particles from a plate (non-rebounded), 2) those that had rebounded from the plate and were then captured onto an adjacent sampling plate, and 3) particles from ambient air using a separate impactor sampler. Preliminary results show that more than 90% of non-rebounded particles consisted of nanosphere soot with or without coatings. The coatings mostly consisted of organic matter. Although rebounded particles also contain nanosphere soot (number fraction 64-69%), they were mostly internally mixed with sulfate, organic matter, or their mixtures. TEM tilted images suggested that the rebounded particles were less deformed on the substrate, whereas the non-rebounded particles were more deformed, which could

Nuclear track radiography of 'hot' aerosol particles

CERN Document Server

Boulyga, S F; Kievets, M K; Lomonosova, E M; Zhuk, I V; Yaroshevich, O I; Perelygin, V P; Petrova, R I; Brandt, R; Vater, P

1999-01-01

Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the alpha-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (gamma,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 9 Pu and sup 2 sup 4 sup 1 Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10 sup - sup 6 Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical imag...

Aerosol particle transport modeling for preclosure safety studies of nuclear waste repositories

International Nuclear Information System (INIS)

Gelbard, F.

1989-01-01

An important concern for preclosure safety analysis of a nuclear waste repository is the potential release to the environment of respirable aerosol particles. Such particles, less than 10 μm in aerodynamic diameter, may have significant adverse health effects if inhaled. To assess the potential health effects of these particles, it is not sufficient to determine the mass fraction of respirable aerosol. The chemical composition of the particles is also of importance since different radionuclides may pose vastly different health hazards. Thus, models are needed to determine under normal and accident conditions the particle size and the chemical composition distributions of aerosol particles as a function of time and of position in the repository. In this work a multicomponent sectional aerosol model is used to determine the aerosol particle size and composition distributions in the repository. A range of aerosol mass releases with varying mean particle sizes and chemical compositions is used to demonstrate the sensitivities and uncertainties of the model. Decontamination factors for some locations in the repository are presented. 8 refs., 1 tab

Properties of Arctic Aerosol Particles and Residuals of Warm Clouds: Cloud Activation Efficiency and the Aerosol Indirect Effect

Science.gov (United States)

Zelenyuk, A.; Imre, D. G.; Leaitch, R.; Ovchinnikov, M.; Liu, P.; Macdonald, A.; Strapp, W.; Ghan, S. J.; Earle, M. E.

2012-12-01

Single particle mass spectrometer, SPLAT II, was used to characterize the size, composition, number concentration, density, and shape of individual Arctic spring aerosol. Background particles, particles above and below the cloud, cloud droplet residuals, and interstitial particles were characterized with goal to identify the properties that separate cloud condensation nuclei (CCN) from background aerosol particles. The analysis offers a comparison between warm clouds formed on clean and polluted days, with clean days having maximum particle concentrations (Na) lower than ~250 cm-3, as compared with polluted days, in which maximum concentration was tenfold higher. On clean days, particles were composed of organics, organics mixed with sulfates, biomass burning (BB), sea salt (SS), and few soot and dust particles. On polluted days, BB, organics associated with BB, and their mixtures with sulfate dominated particle compositions. Based on the measured compositions and size distributions of cloud droplet residuals, background aerosols, and interstitial particles, we conclude that these three particle types had virtually the same compositions, which means that cloud activation probabilities were surprisingly nearly composition independent. Moreover, these conclusions hold in cases in which less than 20% or more than 90% of background particles got activated. We concluded that for the warm clouds interrogated in this study particle size played a more important factor on aerosol CCN activity. Comparative analysis of all studied clouds reveals that aerosol activation efficiency strongly depends on the aerosol concentrations, such that at Na <200 cm-3, nearly all particles activate, and at higher concentrations the activation efficiency is lower. For example, when Na was greater than 1500 cm-3, less than ~30% of particles activated. The data suggest that as the number of nucleated droplets increases, condensation on existing droplets effectively competes with particle

Nuclear microprobe analysis and source apportionment of individual atmospheric aerosol particles

International Nuclear Information System (INIS)

Artaxo, P.; Rabello, M.L.C.; Watt, F.; Grime, G.; Swietlicki, E.

1993-01-01

In atmospheric aerosol reserach, one key issue is to determine the sources of the airborne particles. Bulk PIXE analysis coupled with receptor modeling provides a useful, but limited view of the aerosol sources influencing one particular site or sample. The scanning nuclear microprobe (SNM) technique is a microanalytical technique that gives unique information on individual aerosol particles. In the SNM analyses a 1.0 μm size 2.4 MeV proton beam from the Oxford SNM was used. The trace elements with Z>11 were measured by the particle induced X-ray emission (PIXE) method with detection limits in the 1-10 ppm range. Carbon, nitrogen and oxygen are measured simultaneously using Rutherford backscattering spectrometry (RBS). Atmospheric aerosol particles were collected at the Brazilian Antarctic Station and at biomass burning sites in the Amazon basin tropical rain forest in Brazil. In the Antarctic samples, the sea-salt aerosol particles were clearly predominating, with NaCl and CaSO 4 as major compounds with several trace elements as Al, Si, P, K, Mn, Fe, Ni, Cu, Zn, Br, Sr, and Pb. Factor analysis of the elemental data showed the presence of four components: 1) Soil dust particles; 2) NaCl particles; 3) CaSO 4 with Sr; and 4) Br and Mg. Strontium, observed at 20-100 ppm levels, was always present in the CaSO 4 particles. The hierarchical cluster procedure gave results similar to the ones obtained through factor analysis. For the tropical rain forest biomass burning aerosol emissions, biogenic particles with a high organic content dominate the particle population, while K, P, Ca, Mg, Zn, and Si are the dominant elements. Zinc at 10-200 ppm is present in biogenic particles rich in P and K. The quantitative aspects and excellent detection limits make SNM analysis of individual aerosol particles a very powerful analytical tool. (orig.)

A recirculation aerosol wind tunnel for evaluating aerosol samplers and measuring particle penetration through protective clothing materials.

Science.gov (United States)

Jaques, Peter A; Hsiao, Ta-Chih; Gao, Pengfei

2011-08-01

A recirculation aerosol wind tunnel was designed to maintain a uniform airflow and stable aerosol size distribution for evaluating aerosol sampler performance and determining particle penetration through protective clothing materials. The oval-shaped wind tunnel was designed to be small enough to fit onto a lab bench, have optimized dimensions for uniformity in wind speed and particle size distributions, sufficient mixing for even distribution of particles, and minimum particle losses. Performance evaluation demonstrates a relatively high level of spatial uniformity, with a coefficient of variation of 1.5-6.2% for wind velocities between 0.4 and 2.8 m s(-1) and, in this range, 0.8-8.5% for particles between 50 and 450 nm. Aerosol concentration stabilized within the first 5-20 min with, approximately, a count median diameter of 135 nm and geometric standard deviation of 2.20. Negligible agglomerate growth and particle loss are suggested. The recirculation design appears to result in unique features as needed for our research.

DUSTER: collection of meteoric CaO and carbon smoke particles in the upper stratosphere .

Science.gov (United States)

Della Corte, V.; Rietmeijer, F. J. M.; Rotundi, A.; Ferrari, M.; Palumbo, P.

Nanometer- to micrometer-size particles present in the upper stratosphere are a mixture of terrestrial and extra-terrestrial origins. They can be extraterrestrial particles condensed after meteor ablation. Meteoric dust in bolides is occasionally deposited into the lower stratosphere around 20 km altitude. Nanometer CaO and pure carbon smoke particles were collected at 38 km altitude in the upper stratosphere in the Arctic during June 2008 using DUSTER (Dust in the Upper Stratosphere Tracking Experiment and Retrieval), a balloon-borne instrument for the non-destructive collection of solid particles between 200 nm to 40 microns. We report the collection of micron sized CaCO_3 (calcite) grains. Their morphologies show evidence of melting and condensation after vaporization suggest at temperatures of approximately 3500 K. The formation environment of the collected grains was probably a dense dust cloud formed by the disintegration of a carbonaceous meteoroid during deceleration in the Earth� atmosphere. For the first time, DUSTER collected meteor ablation products that were presumably associated with the disintegration of a bolide crossing the Earth's atmosphere. The collected mostly CaO and pure carbon nanoparticles from the debris cloud of a fireball, included: 1) intact fragments; 2) quenched melted grains; and 3) vapor phase condensation products. The DUSTER project was funded by the Italian Space Agency (ASI), PRIN2008/MIUR (Ministero dell'Istruzione dell'Universitá e della Ricerca), PNRA 2013(Piano Nazionale Ricerca Antartide). CNES graciously provided this flight opportunity. We thank E. Zona and S. Inarta at the Laboratorio di Fisica Cosmica INAF, Osservatorio Astronomico di Capodimonte-Universitá di Napoli Parthenope. F.J.M.R. was supported by grant NNX07AI39G from the NASA Cosmochemistry Program. We thank three anonymous reviewers who assisted us in introducing our new instrument.

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

Single-particle characterization of the high-Arctic summertime aerosol

Directory of Open Access Journals (Sweden)

B. Sierau

2014-07-01

Full Text Available Single-particle mass-spectrometric measurements were carried out in the high Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS. The instrument deployed was an aerosol time-of-flight mass spectrometer (ATOFMS that provides information on the chemical composition of individual particles and their mixing state in real time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 and 3000 nm in diameter showed mass-spectrometric patterns, indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the high Arctic. To assess the importance of long-range particle sources for aerosol–cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest the presence of a particle type of

Contributions of Organic Sources to Atmospheric Aerosol Particle Concentrations and Growth

Science.gov (United States)

Russell, L. M.

2017-12-01

Organic molecules are important contributors to aerosol particle mass and number concentrations through primary emissions as well as secondary growth in the atmosphere. New techniques for measuring organic aerosol components in atmospheric particles have improved measurements of this contribution in the last 20 years, including Scanning Transmission X-ray Microscopy Near Edge X-ray Absorption Fine Structure (STXM-NEXAFS), Fourier Transform Infrared spectroscopy (FTIR), and High-Resolution Aerosol Mass Spectrometry (AMS). STXM-NEXAFS individual aerosol particle composition illustrated the variety of morphology of organic components in marine aerosols, the inherent relationships between organic composition and shape, and the links between atmospheric aerosol composition and particles produced in smog chambers. This type of single particle microscopy has also added to size distribution measurements by providing evidence of how surface-controlled and bulk-controlled processes contribute to the growth of particles in the atmosphere. FTIR analysis of organic functional groups are sufficient to distinguish combustion, marine, and terrestrial organic particle sources and to show that each of those types of sources has a surprisingly similar organic functional group composition over four different oceans and four different continents. Augmenting the limited sampling of these off-line techniques with side-by-side inter-comparisons to online AMS provides complementary composition information and consistent quantitative attribution to sources (despite some clear method differences). Single-particle AMS techniques using light scattering and event trigger modes have now also characterized the types of particles found in urban, marine, and ship emission aerosols. Most recently, by combining with off-line techniques, single particle composition measurements have separated and quantified the contributions of organic, sulfate and salt components from ocean biogenic and sea spray

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.

Gravitational agglomeration of post-HCDA LMFBR aerosols: nonspherical particles

International Nuclear Information System (INIS)

Tuttle, R.F.; Loyalka, S.K.

1982-12-01

Aerosol behavior analysis computer programs have shown that temporal aerosol size distributions in nuclear reactor containments are sensitive to shape factors. This research investigates shape factors by a detailed theoretical analysis of hydrodynamic interactions between a nonspherical particle and a spherical particle undergoing gravitational collisions in an LMFBR environment. First, basic definitions and expressions for settling speeds and collisional efficiencies of nonspherical particles are developed. These are then related to corresponding quantities for spherical particles through shape factors. Using volume equivalent diameter as the defining length in the gravitational collision kernel, the aerodynamic shape factor, the density correction factor, and the gravitational collision shape factor, are introduced to describe the collision kernel for collisions between aerosol agglomerates. The Navier-Stokes equation in oblate spheroidal coordinates is solved to model a nonspherical particle and then the dynamic equations for two particle motions are developed. A computer program (NGCEFF) is constructed, and the dynamical equations are solved by Gear's method

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%.

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

Non-ammonium reduced nitrogen species in atmospheric aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Dod, R.L.; Gundel, L.A.; Benner, W.H.; Novakov, T.

1983-08-01

The traditional belief that ambient aerosol particles contain nitrogen predominantly in the form of inorganic ionic species such as NH/sub 4//sup +/ and NO/sub 3//sup -/ was challenged about 10 years ago by results from x-ray photoelectron spectroscopic analysis (ESCA) of California aerosol particles. A significant fraction (approx. 50%) of the reduced nitrogen was observed to have an oxidation state more reduced than ammonium, characteristic of organic nitrogen species. We have used a recently developed thermal evolved gas analysis method (NO/sub x/) in conjunction with ESCA to confirm the existence of these species in aerosol particles collected in both the United States and Europe. The agreement of EGA and ESCA analyses indicates that these species are found not only on the surface but also throughout the particles. 9 references, 6 figures.

Measurement of particle size distribution and mass concentration of nuclear fuel aerosols

International Nuclear Information System (INIS)

Pickering, S.

1982-01-01

The particle size distribution and particle mass concentration of a nuclear fuel aerosol is measured by admitting the aerosol into a vertically-extending container, positioning an alpha particle detector within the container so that its window is horizontal and directed vertically, stopping the admission of aerosol into the container, detecting the alpha-activity of the particles of the aerosol sedimenting onto the detector window (for example in a series of equal time intervals until a constant level is reached), and converting the alpha-activity measurements into particle size distribution and/or particle mass concentration measurements. The detector is attached to a pivotted arm and by raising a counterweight can be lowered from the container for cleaning. (author)

Measurements of size and composition of particles in polar stratospheric clouds from infrared solar absorption spectra

International Nuclear Information System (INIS)

Kinne, S.; Toon, O.B.; Toon, G.C.; Farmer, C.B.; Browell, E.V.; McCormick, M.P.

1989-01-01

The attenuation of solar radiation between 1.8- and 15-μm wavelength was measured with the airborne Jet Propulsion Laboratory Mark IV interferometer during the Airborne Antarctic Ozone Expedition in 1987. The measurements not only provide information about the abundance of stratospheric gases, but also about the optical depths of polar stratospheric clouds (PSCs) at wavelengths of negligible gas absorption. The spectral dependence of the PSC optical depth contains information about PSC particle size and particle composition. Thirty-three PSC cases were analyzed and categorized into two types. Type I clouds contain particles with radii of about 0.5 μm and nitric acid concentrations greater than 40%. Type II clouds contain particles composed of water ice with radii of 6 μm and larger. Cloud altitudes were determined from 1.064-μm backscattering observations of the airborne Langley DIAL lidar system. Based on the PSC geometrical thickness, both mass and particle density were estimated. Type I clouds typically had visible wavelength optical depths of about 0.008, mass densities of about 20 ppb, and about 2 particles/cm 3 . The observed type II clouds had optical depths of about 0.03, mass densities of about 400 ppb mass, and about 0.03 particles/cm 3 . The detected PSC type I clouds extended to altitudes of 21 km and were nearly in the ozone-depleted region of the polar stratosphere. The observed type II cases during September were predominantly found at altitudes below 15 km

Microphysical processing of aerosol particles in orographic clouds

Directory of Open Access Journals (Sweden)

S. Pousse-Nottelmann

2015-08-01

aerosol cycling in clouds has been implemented into COSMO-Model, the regional weather forecast and climate model of the Consortium for Small-scale Modeling (COSMO. The effects of aerosol scavenging, cloud microphysical processing and regeneration upon cloud evaporation on the aerosol population and on subsequent cloud formation are investigated. For this, two-dimensional idealized simulations of moist flow over two bell-shaped mountains were carried out varying the treatment of aerosol scavenging and regeneration processes for a warm-phase and a mixed-phase orographic cloud. The results allowed us to identify different aerosol cycling mechanisms. In the simulated non-precipitating warm-phase cloud, aerosol mass is incorporated into cloud droplets by activation scavenging and released back to the atmosphere upon cloud droplet evaporation. In the mixed-phase cloud, a first cycle comprises cloud droplet activation and evaporation via the Wegener–Bergeron–Findeisen (WBF process. A second cycle includes below-cloud scavenging by precipitating snow particles and snow sublimation and is connected to the first cycle via the riming process which transfers aerosol mass from cloud droplets to snowflakes. In the simulated mixed-phase cloud, only a negligible part of the total aerosol mass is incorporated into ice crystals. Sedimenting snowflakes reaching the surface remove aerosol mass from the atmosphere. The results show that aerosol processing and regeneration lead to a vertical redistribution of aerosol mass and number. Thereby, the processes impact the total aerosol number and mass and additionally alter the shape of the aerosol size distributions by enhancing the internally mixed/soluble Aitken and accumulation mode and generating coarse-mode particles. Concerning subsequent cloud formation at the second mountain, accounting for aerosol processing and regeneration increases the cloud droplet number concentration with possible implications for the ice crystal number

Hygroscopic growth of atmospheric aerosol particles and its relation to nucleation scavenging in clouds

Energy Technology Data Exchange (ETDEWEB)

Svenningsson, B.

1997-11-01

Aerosol particles in the atmosphere are important in several aspects. Some major aerosol constituents that are deposited in ecosystems are acidic or fertilizers and some minor or trace constituents are toxic. Aerosol particles are also involved in the earth`s radiation balance, both directly by scattering the sunlight and indirectly by influencing the clouds. All these effects are influenced by the interaction between the aerosol particles and water vapour. A tandem differential mobility analyser (TDMA) has been designed to measure hygroscopic growth, i.e. the particle diameter change due to uptake of water at well defined relative humidities below 100%. Tests of the instrument performance have been made using aerosol particles of pure inorganic salts. Three field experiments have been performed as parts of large fog and cloud experiments. Bimodal hygroscopic growth spectra were found: less-hygroscopic particles containing a few percent and more-hygroscopic particles around 50% by volume of hygroscopically active material. In general the fraction of less-hygroscopic particles decreases with particle size and it is larger in polluted continental aerosols than in remote background aerosols. This external mixing cannot be fully understood using present views on the formation of aerosols. Evidence or the importance of the external mixing on the cloud nucleating properties of the particles are found in comparisons between hygroscopic growth spectra for the total aerosol, the interstitial aerosol in clouds, and cloud drop residuals. Cloud condensation nuclei spectra, calculated using aerosol particle size distributions and hygroscopic growth spectra, in combination with information on the major inorganic ions are presented. These CCN spectra reveal for instance that the influence of less-hygroscopic particles on the cloud droplets increases with increasing peak supersaturation. The fraction of the particles that were scavenged to cloud drops, as a function of particle

Synchrotron x-ray fluorescence analyses of stratospheric cosmic dust: New results for chondritic and nickel-depleted particles

International Nuclear Information System (INIS)

Flynn, G.J.; Sutton, S.R.

1989-06-01

Trace element abundance determinations were performed using synchrotron x-ray fluorescence on nine particles collected from the stratosphere and classified as ''cosmic''. Improvements to the Synchrotron Light Source allowed the detection of all elements between Cr and Mo, with the exceptions of Co and As, in our largest particle. The minor and trace element abundance patterns of three Ni-depleted particles were remarkably similar to those of extraterrestrial igneous rocks. Fe/Ni and Fe/Mn ratios suggest that one of these may be of lunar origin. All nine particles exhibited an enrichment in Br, ranging form 1.3 to 38 times the Cl concentration. Br concentrations were uncorrelated with particle size, as would be expected for a surface correlated component acquires from the stratosphere. 27 refs., 4 figs., 2 tabs

Synthesis of nanosized metal particles from an aerosol

Directory of Open Access Journals (Sweden)

Srećko R. Stopić

2013-10-01

Full Text Available The synthesis of metallic nanoparticles from the precursor solution of salts using the ultrasonic spray pyrolysis method was considered in this work. During the control of process parameters (surface tension and density, the concentration of solution, residence time of aerosol in the reactor, presence of additives, gas flow rate, decomposition temperature of aerosol, type of precursor and working atmosphere it is possible to guide the process in order to obtain powders with such a morphology which satisfies more complex requirements for the desired properties of advanced engineering materials.  Significant advance in the improvement of powder characteristics (lower particles sizes, better spheroidity, higher surface area was obtained by the application of the ultrasonic generator for the preparation of aerosols. Ultrasonic spray pyrolysis is performed by the action of a powerful source of ultrasound on the corresponding precursor solution forming the aerosol with a constant droplet size, which depends on the characteristics of liquid and the frequency of ultrasound. The produced aerosols were transported into the hot reactor, which enables the reaction to occur in a very small volume of a particle and formation of  nanosized powder. Spherical, nanosized particles of metals (Cu, Ag, Au, Co were produced with new and improved physical and chemical characteristics at the IME, RWTH Aachen University. The high costs associated with small quantities of produced nanosized particles represent a limitation of the USP-method. Therefore, scale up of the ultrasonic spray pyrolysis was performed as a final target in the synthesis of nanosized powder.

Measurements of Primary Biogenic Aerosol Particles with an Ultraviolet Aerodynamic Particle Sizer (UVAPS) During AMAZE-08

Science.gov (United States)

Wollny, A. G.; Garland, R.; Pöschl, U.

2008-12-01

Biogenic aerosols are ubiquitous in the Earth's atmosphere and they influence atmospheric chemistry and physics, the biosphere, climate, and public health. They play an important role in the spread of biological organisms and reproductive materials, and they can cause or enhance human, animal, and plant diseases. Moreover, they influence the Earth's energy budget by scattering and absorbing radiation, and they can initiate the formation of clouds and precipitation as cloud condensation and ice nuclei. The composition, abundance, and origin of biogenic aerosol particles and components are, however, still not well understood and poorly quantified. Prominent examples of primary biogenic aerosol particles, which are directly emitted from the biosphere to the atmosphere, are pollen, bacteria, fungal spores, viruses, and fragments of animals and plants. During the AMazonian Aerosol CharacteriZation Experiment (AMAZE-08) a large number of aerosol and gas-phase measurements were taken on a remote site close to Manaus, Brazil, during a period of five weeks in February and March 2008. The presented study is focused on data from an ultraviolet aerodynamic particle sizer (UVAPS, TSI inc.) that has been deployed for the first time in Amazonia. In this instrument, particle counting and aerodynamic sizing over the range of 0.5-20 μm are complemented by the measurement of UV fluorescence at 355 nm (excitation) and 420-575 nm (emission), respectively. Fluorescence at these wavelengths is characteristic for reduced pyridine nucleotides (e.g., NAD(P)H) and for riboflavin, which are specific for living cells. Thus particles exhibiting fluorescence signals can be regarded as 'viable aerosols' or 'fluorescent bioparticles' (FBAP), and their concentration can be considered as lower limit for the actual abundance of primary biogenic aerosol particles. First data analyses show a pronounced peak of FBAP at diameters around 2-3 μm. In this size range the biogenic particle fraction was

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.

Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation

Directory of Open Access Journals (Sweden)

E. Asmi

2010-05-01

Full Text Available The Antarctic near-coastal sub-micrometre aerosol particle features in summer were characterised based on measured data on aerosol hygroscopicity, size distributions, volatility and chemical ion and organic carbon mass concentrations. Hysplit model was used to calculate the history of the air masses to predict the particle origin. Additional measurements of meteorological parameters were utilised. The hygroscopic properties of particles mostly resembled those of marine aerosols. The measurements took place at 130 km from the Southern Ocean, which was the most significant factor affecting the particle properties. This is explained by the lack of additional sources on the continent of Antarctica. The Southern Ocean was thus a likely source of the particles and nucleating and condensing vapours. The particles were very hygroscopic (HGF 1.75 at 90 nm and very volatile. Most of the sub-100 nm particle volume volatilised below 100 °C. Based on chemical data, particle hygroscopic and volatile properties were explained by a large fraction of non-neutralised sulphuric acid together with organic material. The hygroscopic growth factors assessed from chemical data were similar to measured. Hygroscopicity was higher in dry continental air masses compared with the moist marine air masses. This was explained by the aging of the marine organic species and lower methanesulphonic acid volume fraction together with the changes in the inorganic aerosol chemistry as the aerosol had travelled long time over the continental Antarctica. Special focus was directed in detailed examination of the observed new particle formation events. Indications of the preference of negative over positive ions in nucleation could be detected. However, in a detailed case study, the neutral particles dominated the particle formation process. Freshly nucleated particles had the smallest hygroscopic growth factors, which increased subsequent to particle aging.

Aerosolization, Chemical Characterization, Hygroscopicity and Ice Formation of Marine Biogenic Particles

Science.gov (United States)

Alpert, P. A.; Radway, J.; Kilthau, W.; Bothe, D.; Knopf, D. A.; Aller, J. Y.

2013-12-01

The oceans cover the majority of the earth's surface, host nearly half the total global primary productivity and are a major source of atmospheric aerosol particles. However, effects of biological activity on sea spray generation and composition, and subsequent cloud formation are not well understood. Our goal is to elucidate these effects which will be particularly important over nutrient rich seas, where microorganisms can reach concentrations of 10^9 per mL and along with transparent exopolymer particles (TEP) can become aerosolized. Here we report the results of mesocosm experiments in which bubbles were generated by two methods, either recirculating impinging water jets or glass frits, in natural or artificial seawater containing bacteria and unialgal cultures of three representative phytoplankton species, Thalassiosira pseudonana, Emiliania huxleyi, and Nannochloris atomus. Over time we followed the size distribution of aerosolized particles as well as their hygroscopicity, heterogeneous ice nucleation potential, and individual physical-chemical characteristics. Numbers of cells and the mass of dissolved and particulate organic carbon (DOC, POC), TEP (which includes polysaccharide-containing microgels and nanogels >0.4 μm in diameter) were determined in the bulk water, the surface microlayer, and aerosolized material. Aerosolized particles were also impacted onto substrates for ice nucleation and water uptake experiments, elemental analysis using computer controlled scanning electron microscopy and energy dispersive analysis of X-rays (CCSEM/EDX), and determination of carbon bonding with scanning transmission X-ray microscopy and near-edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). Regardless of bubble generation method, the overall concentration of aerosol particles, TEP, POC and DOC increased as concentrations of bacterial and phytoplankton cells increased, stabilized, and subsequently declined. Particles cloud formation and potential

Time Resolved Measurements of Primary Biogenic Aerosol Particles in Amazonia

Science.gov (United States)

Wollny, A. G.; Garland, R.; Pöschl, U.

2009-04-01

Biogenic aerosols are ubiquitous in the Earth's atmosphere and they influence atmospheric chemistry and physics, the biosphere, climate, and public health. They play an important role in the spread of biological organisms and reproductive materials, and they can cause or enhance human, animal, and plant diseases. Moreover, they influence the Earth's energy budget by scattering and absorbing radiation, and they can initiate the formation of clouds and precipitation as cloud condensation and ice nuclei. The composition, abundance, and origin of biogenic aerosol particles and components are, however, still not well understood and poorly quantified. Prominent examples of primary biogenic aerosol particles, which are directly emitted from the biosphere to the atmosphere, are pollen, bacteria, fungal spores, viruses, and fragments of animals and plants. During the Amazonian Aerosol Characterization Experiment (AMAZE-08) a large number of aerosol and gas-phase measurements were taken on a remote site close to Manaus, Brazil, during a period of five weeks in February and March 2008. This presented study is focused on data from an ultraviolet aerodynamic particle sizer (UVAPS, TSI inc.) that has been deployed for the first time in Amazonia. In this instrument, particle counting and aerodynamic sizing over the range of 0.5-20 µm are complemented by the measurement of UV fluorescence at 355 nm (excitation) and 420-575 nm (emission), respectively. Fluorescence at these wavelengths is characteristic for reduced pyridine nucleotides (e.g., NAD(P)H) and for riboflavin, which are specific for living cells. Thus particles exhibiting fluorescence signals can be regarded as "viable aerosols" or "fluorescent bioparticles" (FBAP), and their concentration can be considered as lower limit for the actual abundance of primary biogenic aerosol particles. Data from the UVAPS were averaged over 5 minute time intervals. The presence of bioparticles in the observed size range has been

Reactions and mass spectra of complex particles using Aerosol CIMS

Science.gov (United States)

Hearn, John D.; Smith, Geoffrey D.

2006-12-01

Aerosol chemical ionization mass spectrometry (CIMS) is used both on- and off-line for the analysis of complex laboratory-generated and ambient particles. One of the primary advantages of Aerosol CIMS is the low degree of ion fragmentation, making this technique well suited for investigating the reactivity of complex particles. To demonstrate the usefulness of this "soft" ionization, particles generated from meat cooking were reacted with ozone and the composition was monitored as a function of reaction time. Two distinct kinetic regimes were observed with most of the oleic acid in these particles reacting quickly but with 30% appearing to be trapped in the complex mixture. Additionally, detection limits are measured to be sufficiently low (100-200 ng/m3) to detect some of the more abundant constituents in ambient particles, including sulfate, which is measured in real-time at 1.2 [mu]g/m3. To better characterize complex aerosols from a variety of sources, a novel off-line collection method was also developed in which non-volatile and semi-volatile organics are desorbed from particles and concentrated in a cold U-tube. Desorption from the U-tube followed by analysis with Aerosol CIMS revealed significant amounts of nicotine in cigarette smoke and levoglucosan in oak and pine smoke, suggesting that this may be a useful technique for monitoring particle tracer species. Additionally, secondary organic aerosol formed from the reaction of ozone with R-limonene and volatile organics from orange peel were analyzed off-line showing large molecular weight products (m/z > 300 amu) that may indicate the formation of oligomers. Finally, mass spectra of ambient aerosol collected offline reveal a complex mixture of what appears to be highly processed organics, some of which may contain nitrogen.

New apparatus of single particle trap system for aerosol visualization

Science.gov (United States)

Higashi, Hidenori; Fujioka, Tomomi; Endo, Tetsuo; Kitayama, Chiho; Seto, Takafumi; Otani, Yoshio

2014-08-01

Control of transport and deposition of charged aerosol particles is important in various manufacturing processes. Aerosol visualization is an effective method to directly observe light scattering signal from laser-irradiated single aerosol particle trapped in a visualization cell. New single particle trap system triggered by light scattering pulse signal was developed in this study. The performance of the device was evaluated experimentally. Experimental setup consisted of an aerosol generator, a differential mobility analyzer (DMA), an optical particle counter (OPC) and the single particle trap system. Polystylene latex standard (PSL) particles (0.5, 1.0 and 2.0 μm) were generated and classified according to the charge by the DMA. Singly charged 0.5 and 1.0 μm particles and doubly charged 2.0 μm particles were used as test particles. The single particle trap system was composed of a light scattering signal detector and a visualization cell. When the particle passed through the detector, trigger signal with a given delay time sent to the solenoid valves upstream and downstream of the visualization cell for trapping the particle in the visualization cell. The motion of particle in the visualization cell was monitored by CCD camera and the gravitational settling velocity and the electrostatic migration velocity were measured from the video image. The aerodynamic diameter obtained from the settling velocity was in good agreement with Stokes diameter calculated from the electrostatic migration velocity for individual particles. It was also found that the aerodynamic diameter obtained from the settling velocity was a one-to-one function of the scattered light intensity of individual particles. The applicability of this system will be discussed.

Simulating gas-aerosol-cirrus interactions: Process-oriented microphysical model and applications

Directory of Open Access Journals (Sweden)

B. Kärcher

2003-01-01

Full Text Available This work describes a process-oriented, microphysical-chemical model to simulate the formation and evolution of aerosols and ice crystals under the conditions prevailing in the upper troposphere and lower stratosphere. The model can be run as a box model or along atmospheric trajectories, and considers mixing, gas phase chemistry of aerosol precursors, binary homogeneous aerosol nucleation, homogeneous and heterogeneous ice nucleation, coagulation, condensation and dissolution, gas retention during particle freezing, gas trapping in growing ice crystals, and reverse processes. Chemical equations are solved iteratively using a second order implicit integration method. Gas-particle interactions and coagulation are treated over various size structures, with fully mass conserving and non-iterative numerical solution schemes. Particle types include quinternary aqueous solutions composed of H2SO4, HNO3, HCl, and HBr with and without insoluble components, insoluble aerosol particles, and spherical or columnar ice crystals deriving from each aerosol type separately. Three case studies are discussed in detail to demonstrate the potential of the model to simulate real atmospheric processes and to highlight current research topics concerning aerosol and cirrus formation near the tropopause. Emphasis is placed on how the formation of cirrus clouds and the scavenging of nitric acid in cirrus depends on small-scale temperature fluctuations and the presence of efficient ice nuclei in the tropopause region, corroborating and partly extending the findings of previous studies.

Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin

Science.gov (United States)

Andreae, Meinrat O.; Afchine, Armin; Albrecht, Rachel; Amorim Holanda, Bruna; Artaxo, Paulo; Barbosa, Henrique M. J.; Borrmann, Stephan; Cecchini, Micael A.; Costa, Anja; Dollner, Maximilian; Fütterer, Daniel; Järvinen, Emma; Jurkat, Tina; Klimach, Thomas; Konemann, Tobias; Knote, Christoph; Krämer, Martina; Krisna, Trismono; Machado, Luiz A. T.; Mertes, Stephan; Minikin, Andreas; Pöhlker, Christopher; Pöhlker, Mira L.; Pöschl, Ulrich; Rosenfeld, Daniel; Sauer, Daniel; Schlager, Hans; Schnaiter, Martin; Schneider, Johannes; Schulz, Christiane; Spanu, Antonio; Sperling, Vinicius B.; Voigt, Christiane; Walser, Adrian; Wang, Jian; Weinzierl, Bernadett; Wendisch, Manfred; Ziereis, Helmut

2018-01-01

Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by 1 or 2 orders of magnitude. The measurements were made during the German-Brazilian cooperative aircraft campaign ACRIDICON-CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (global precipitation measurement), on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place in September-October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN) and cloud condensation nuclei (CCN) number concentrations and chemical species mass concentrations. The UT particles differed sharply in their chemical composition and size distribution from those in the PBL, ruling out convective transport of combustion-derived particles from the boundary layer (BL) as a source. The air in the immediate outflow of deep convective clouds was depleted of aerosol particles, whereas strongly enhanced number concentrations of small particles ( 90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our findings suggest a conceptual model, where production of new aerosol particles takes place in the continental UT from biogenic volatile organic material brought up by deep convection and converted to condensable

Inverse problem for particle size distributions of atmospheric aerosols using stochastic particle swarm optimization

International Nuclear Information System (INIS)

Yuan Yuan; Yi Hongliang; Shuai Yong; Wang Fuqiang; Tan Heping

2010-01-01

As a part of resolving optical properties in atmosphere radiative transfer calculations, this paper focuses on obtaining aerosol optical thicknesses (AOTs) in the visible and near infrared wave band through indirect method by gleaning the values of aerosol particle size distribution parameters. Although various inverse techniques have been applied to obtain values for these parameters, we choose a stochastic particle swarm optimization (SPSO) algorithm to perform an inverse calculation. Computational performances of different inverse methods are investigated and the influence of swarm size on the inverse problem of computation particles is examined. Next, computational efficiencies of various particle size distributions and the influences of the measured errors on computational accuracy are compared. Finally, we recover particle size distributions for atmospheric aerosols over Beijing using the measured AOT data (at wavelengths λ=0.400, 0.690, 0.870, and 1.020 μm) obtained from AERONET at different times and then calculate other AOT values for this band based on the inverse results. With calculations agreeing with measured data, the SPSO algorithm shows good practicability.

Characterization of aerosol particles at the forested site in Lithuania

Science.gov (United States)

Rimselyte, I.; Garbaras, A.; Kvietkus, K.; Remeikis, V.

2009-04-01

Atmospheric particulate matter (PM), especially fine particles (particles with aerodynamic diameter less than 1 m, PM1), has been found to play an important role in global climate change, air quality, and human health. The continuous study of aerosol parameters is therefore imperative for better understanding the environmental effects of the atmospheric particles, as well as their sources, formation and transformation processes. The particle size distribution is particularly important, since this physical parameter determines the mass and number density, lifetime and atmospheric transport, or optical scattering behavior of the particles in the atmosphere (Jaenicke, 1998). Over the years several efforts have been made to improve the knowledge about the chemical composition of atmospheric particles as a function of size (Samara and Voutsa, 2005) and to characterize the relative contribution of different components to the fine particulate matter. It is well established that organic materials constitute a highly variable fraction of the atmospheric aerosol. This fraction is predominantly found in the fine size mode in concentrations ranging from 10 to 70% of the total dry fine particle mass (Middlebrook et al., 1998). Although organic compounds are major components of the fine particles, the composition, formation mechanism of organic aerosols are not well understood. This is because particulate organic matter is part of a complex atmospheric system with hundreds of different compounds, both natural and anthropogenic, covering a wide range of chemical properties. The aim of this study was to characterize the forest PM1, and investigate effects of air mass transport on the aerosol size distribution and chemical composition, estimate and provide insights into the sources and characteristics of carbonaceous aerosols through analysis ^13C/12C isotopic ratio as a function of the aerosol particles size. The measurements were performed at the Rugšteliškis integrated

Particle-Resolved Modeling of Aerosol Mixing State in an Evolving Ship Plume

Science.gov (United States)

Riemer, N. S.; Tian, J.; Pfaffenberger, L.; Schlager, H.; Petzold, A.

2011-12-01

The aerosol mixing state is important since it impacts the particles' optical and CCN properties and thereby their climate impact. It evolves continuously during the particles' residence time in the atmosphere as a result of coagulation with other particles and condensation of secondary aerosol species. This evolution is challenging to represent in traditional aerosol models since they require the representation of a multi-dimensional particle distribution. While modal or sectional aerosol representations cannot practically resolve the aerosol mixing state for more than a few species, particle-resolved models store the composition of many individual aerosol particles directly. They thus sample the high-dimensional composition state space very efficiently and so can deal with tens of species, fully resolving the mixing state. Here we use the capabilities of the particle-resolved model PartMC-MOSAIC to simulate the evolution of particulate matter emitted from marine diesel engines and compare the results to aircraft measurements made in the English Channel in 2007 as part of the European campaign QUANTIFY. The model was initialized with values of gas concentrations and particle size distributions and compositions representing fresh ship emissions. These values were obtained from a test rig study in the European project HERCULES in 2006 using a serial four-stroke marine diesel engine operating on high-sulfur heavy fuel oil. The freshly emitted particles consisted of sulfate, black carbon, organic carbon and ash. We then tracked the particle population for several hours as it evolved undergoing coagulation, dilution with the background air, and chemical transformations in the aerosol and gas phase. This simulation was used to compute the evolution of CCN properties and optical properties of the plume on a per-particle basis. We compared our results to size-resolved data of aged ship plumes from the QUANTIFY Study in 2007 and showed that the model was able to reproduce

Ice Nucleation Activity of Various Agricultural Soil Dust Aerosol Particles

Science.gov (United States)

Schiebel, Thea; Höhler, Kristina; Funk, Roger; Hill, Thomas C. J.; Levin, Ezra J. T.; Nadolny, Jens; Steinke, Isabelle; Suski, Kaitlyn J.; Ullrich, Romy; Wagner, Robert; Weber, Ines; DeMott, Paul J.; Möhler, Ottmar

2016-04-01

Recent investigations at the cloud simulation chamber AIDA (Aerosol Interactions and Dynamics in the Atmosphere) suggest that agricultural soil dust has an ice nucleation ability that is enhanced up to a factor of 10 compared to desert dust, especially at temperatures above -26 °C (Steinke et al., in preparation for submission). This enhancement might be caused by the contribution of very ice-active biological particles. In addition, soil dust aerosol particles often contain a considerably higher amount of organic matter compared to desert dust particles. To test agricultural soil dust as a source of ice nucleating particles, especially for ice formation in warm clouds, we conducted a series of laboratory measurements with different soil dust samples to extend the existing AIDA dataset. The AIDA has a volume of 84 m3 and operates under atmospherically relevant conditions over wide ranges of temperature, pressure and humidity. By controlled adiabatic expansions, the ascent of an air parcel in the troposphere can be simulated. As a supplement to the AIDA facility, we use the INKA (Ice Nucleation Instrument of the KArlsruhe Institute of Technology) continuous flow diffusion chamber based on the design by Rogers (1988) to expose the sampled aerosol particles to a continuously increasing saturation ratio by keeping the aerosol temperature constant. For our experiments, soil dust was dry dispersed into the AIDA vessel. First, fast saturation ratio scans at different temperatures were performed with INKA, sampling soil dust aerosol particles directly from the AIDA vessel. Then, we conducted the AIDA expansion experiment starting at a preset temperature. The combination of these two different methods provides a robust data set on the temperature-dependent ice activity of various agriculture soil dust aerosol particles with a special focus on relatively high temperatures. In addition, to extend the data set, we investigated the role of biological and organic matter in more

Molecular dynamics simulations of laser disintegration of amorphous aerosol particles with spatially nonuniform absorption

International Nuclear Information System (INIS)

Schoolcraft, Tracy A.; Constable, Gregory S.; Jackson, Bryan; Zhigilei, Leonid V.; Garrison, Barbara J.

2001-01-01

A series of molecular dynamics (MD) simulations are performed in order to provide qualitative information on the mechanisms of disintegration of aerosol particles as used in aerosol mass spectrometry. Three generic types of aerosol particles are considered: strongly absorbing particles with homogeneous composition, transparent particles with absorbing inclusion, and absorbing particles with transparent inclusion. To study the effect of the mechanical properties of the aerosol material on the disintegration process, the results for crystalline (brittle) and amorphous (ductile) particles are compared. For large laser fluences, nearly complete dissociation of the absorbing material is observed, whereas the nonabsorbing portions remain fairly intact. Because large fluences can cause photofragmentation of constituent molecules, multiple pulses at low laser fluence and/or lasers with different wavelengths are recommended for the best representative sampling of multicomponent aerosol particles in laser desorption/ionization (LDI) mass spectrometry

Physicochemical characterization of Capstone depleted uranium aerosols I: uranium concentration in aerosols as a function of time and particle size.

Science.gov (United States)

Parkhurst, Mary Ann; Cheng, Yung Sung; Kenoyer, Judson L; Traub, Richard J

2009-03-01

During the Capstone Depleted Uranium (DU) Aerosol Study, aerosols containing DU were produced inside unventilated armored vehicles (i.e., Abrams tanks and Bradley Fighting Vehicles) by perforation with large-caliber DU penetrators. These aerosols were collected and characterized, and the data were subsequently used to assess human health risks to personnel exposed to DU aerosols. The DU content of each aerosol sample was first quantified by radioanalytical methods, and selected samples, primarily those from the cyclone separator grit chambers, were analyzed radiochemically. Deposition occurred inside the vehicles as particles settled on interior surfaces. Settling rates of uranium from the aerosols were evaluated using filter cassette samples that collected aerosol as total mass over eight sequential time intervals. A moving filter was used to collect aerosol samples over time, particularly within the first minute after a shot. The results demonstrate that the peak uranium concentration in the aerosol occurred in the first 10 s after perforation, and the concentration decreased in the Abrams tank shots to about 50% within 1 min and to less than 2% after 30 min. The initial and maximum uranium concentrations were lower in the Bradley vehicle than those observed in the Abrams tank, and the concentration levels decreased more slowly. Uranium mass concentrations in the aerosols as a function of particle size were evaluated using samples collected in a cyclone sampler, which collected aerosol continuously for 2 h after perforation. The percentages of uranium mass in the cyclone separator stages ranged from 38 to 72% for the Abrams tank with conventional armor. In most cases, it varied with particle size, typically with less uranium associated with the smaller particle sizes. Neither the Abrams tank with DU armor nor the Bradley vehicle results were specifically correlated with particle size and can best be represented by their average uranium mass concentrations of 65

A review of optical measurements at the aerosol and cloud chamber AIDA

International Nuclear Information System (INIS)

Wagner, Robert; Linke, Claudia; Naumann, Karl-Heinz; Schnaiter, Martin; Vragel, Marlen; Gangl, Martin; Horvath, Helmuth

2009-01-01

This paper provides a survey of recent studies on the optical properties of aerosol and cloud particles that have been conducted at the AIDA facility of Forschungszentrum Karlsruhe (Aerosol Interactions and Dynamics in the Atmosphere). Reflecting the broad accessible temperature range of the AIDA chamber which extends from ambient temperature down to 183 K, the investigations feature a broad diversity of research topics, such as the wavelength-dependence of the specific absorption cross sections of soot and mineral dust aerosols at room temperature, depolarization and infrared extinction measurements of ice crystal clouds generated at temperatures below 235 K, and the optical properties of polar stratospheric cloud constituents whose formation was studied in chamber experiments at temperatures well below 200 K. After reviewing the AIDA research activity of the past decade and introducing the optical instrumentation of the AIDA facility, this paper presents illustrative examples of ongoing and already published work on optical measurements of soot aerosols, mineral dust particles, and ice crystal clouds.

Characteristics of agglomerates of sodium oxide aerosol particles: Task 7, topical report

International Nuclear Information System (INIS)

Gieseke, J.A.; Reed, L.D.; Jordan, H.; Lee, K.W.

1977-01-01

Accurate macroscopic predictions of aerosol population behavior within enclosed containments are known to depend strongly upon the microscopic characteristics of the individual aerosols. Also, coagulation rates due to mechanisms which produce relative motions between particles within the suspended aerosol are known to depend upon the cross sectional areas of the individual particles. Hence, it has been the primary concern of this study to examine experimentally the microscopic characteristics of sodium oxide aerosols produced in air. The results of these measurements can now be incorporated into the various macroscopic aerosol behavior prediction models

Formation of charged particles in condensation aerosol generators used for inhalation studies

International Nuclear Information System (INIS)

Ramu, M.C.R.; Vohra, K.G.

1976-01-01

Formation of charged particles in a condensation aerosol generator has been studied using a charge collector and a mobility analyzer. Measurements carried out using the charge collector show that the number of charged particles increases with an increase in the particle diameter. The number of charged particles measured also depends on the thickness of the sodium chloride coating on the platinum wire used in the aerosol generator for the production of condensation nuclei. It was found that the charged particle concentration increases with decreasing coating thickness. Mobility measurements have shown that the particles are singly and doubly charged. It has been estimated that about 10% of the particles produced in the generator are charged. The mechanism of formation of charged particles in the aerosol generator has been briefly discussed. (author)

On the composition and optical extinction of particles in the tropopause region

Energy Technology Data Exchange (ETDEWEB)

Kaercher, B. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere; Solomon, S. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Aeronomy Lab.

1999-06-01

Liquid aerosol particles and ice crystals in subvisible cirrus clouds in the tropopause region are characterized in terms of size distributions, chemical composition, and optical extinction. These particle properties are studied by means of simple models and are related to satellite extinction measurements, particularly for midlatitudes. Sulfuric acid aerosols can take up nitric acid near the ice frost point, just before ice nucleation. Aerosols in the tropopause region may show a larger spread of extinction and extinction ratios at different wavelengths than background stratospheric aerosols. The high surface areas and low extinction ratios of subvisible cirrus deduced from satellite observations are unlikely to be due purely to aerosols, except for high sulfate loadings. It is shown that mixtures of liquid aerosols and ice particles can more readily explain these data with only small cloud fractions along the line of sight of the optical sensors. The efficiency of heterogeneous chlorine activation in aerosol/cloud mixtures, the availability of water vapor, sulfate, and nitrate, and the effects of temperature, ammonium, ice nuclei and aircraft emissions on the properties of particles in the tropopause region are explored. (orig.)

Aircraft measurements over Europe of an air pollution plume from Southeast Asia – aerosol and chemical characterization

Directory of Open Access Journals (Sweden)

A. Stohl

2007-01-01

.70 Mm−1, as was the fraction of non-volatile Aitken particles. This indicates that black carbon (BC was an important aerosol component. During the flight on 25 March, which took place on the rear of a trough located over Europe, a mixture of Asian pollution and stratospheric air was found. Asian pollution was mixing into the lower stratosphere, and stratospheric air was mixing into the pollution plume in the troposphere. Turbulence was encountered by the aircraft in the mixing regions, where the thermal stability was low and Richardson numbers were below 0.2. The result of the mixing can clearly be seen in the trace gas data, which are following mixing lines in correlation plots. This mixing with stratospheric air is likely very typical of Asian air pollution, which is often lifted to the upper troposphere and, thus, transported in the vicinity of stratospheric air.

Nuclear track radiography of 'hot' aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Boulyga, S.F.; Kievitskaja, A.I.; Kievets, M.K.; Lomonosova, E.M.; Zhuk, I.V.; Yaroshevich, O.I.; Perelygin, V.P.; Petrova, R.; Brandt, R.; Vater, P

1999-06-01

Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the {alpha}-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and ({gamma},f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by {sup 235}U, {sup 239}Pu and {sup 241}Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10{sup -6} Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical image of the SSNTD surface obtained through a video camera and the determination of size and activity of 'hot' particles00.

Scattering of aerosol particles by a Hermite-Gaussian beam in marine atmosphere.

Science.gov (United States)

Huang, Qingqing; Cheng, Mingjian; Guo, Lixin; Li, Jiangting; Yan, Xu; Liu, Songhua

2017-07-01

Based on the complex-source-point method and the generalized Lorenz-Mie theory, the scattering properties and polarization of aerosol particles by a Hermite-Gaussian (HG) beam in marine atmosphere is investigated. The influences of beam mode, beam width, and humidity on the scattered field are analyzed numerically. Results indicate that when the number of HG beam modes u (v) increase, the radar cross section of aerosol particles alternating appears at maximum and minimum values in the forward and backward scattering, respectively, because of the special petal-shaped distribution of the HG beam. The forward and backward scattering of aerosol particles decreases with the increase in beam waist. When beam waist is less than the radius of the aerosol particle, a minimum value is observed in the forward direction. The scattering properties of aerosol particles by the HG beam are more sensitive to the change in relative humidity compared with those by the plane wave and the Gaussian beam (GB). The HG beam shows superiority over the plane wave and the GB in detecting changes in the relative humidity of marine atmosphere aerosol. The effects of relative humidity on the polarization of the HG beam have been numerically analyzed in detail.

Polyhexamethylene guanidine phosphate aerosol particles induce pulmonary inflammatory and fibrotic responses.

Science.gov (United States)

Kim, Ha Ryong; Lee, Kyuhong; Park, Chang We; Song, Jeong Ah; Shin, Da Young; Park, Yong Joo; Chung, Kyu Hyuck

2016-03-01

Polyhexamethylene guanidine (PHMG) phosphate was used as a disinfectant for the prevention of microorganism growth in humidifiers, without recognizing that a change of exposure route might cause significant health effects. Epidemiological studies reported that the use of humidifier disinfectant containing PHMG-phosphate can provoke pulmonary fibrosis. However, the pulmonary toxicity of PHMG-phosphate aerosol particles is unknown yet. This study aimed to elucidate the toxicological relationship between PHMG-phosphate aerosol particles and pulmonary fibrosis. An in vivo nose-only exposure system and an in vitro air-liquid interface (ALI) co-culture model were applied to confirm whether PHMG-phosphate induces inflammatory and fibrotic responses in the respiratory tract. Seven-week-old male Sprague-Dawley rats were exposed to PHMG-phosphate aerosol particles for 3 weeks and recovered for 3 weeks in a nose-only exposure chamber. In addition, three human lung cells (Calu-3, differentiated THP-1 and HMC-1 cells) were cultured at ALI condition for 12 days and were treated with PHMG-phosphate at set concentrations and times. The reactive oxygen species (ROS) generation, airway barrier injuries and inflammatory and fibrotic responses were evaluated in vivo and in vitro. The rats exposed to PHMG-phosphate aerosol particles in nanometer size showed pulmonary inflammation and fibrosis including inflammatory cytokines and fibronectin mRNA increase, as well as histopathological changes. In addition, PHMG-phosphate triggered the ROS generation, airway barrier injuries and inflammatory responses in a bronchial ALI co-culture model. Those results demonstrated that PHMG-phosphate aerosol particles cause pulmonary inflammatory and fibrotic responses. All features of fibrogenesis by PHMG-phosphate aerosol particles closely resembled the pathology of fibrosis that was reported in epidemiological studies. Finally, we expected that PHMG-phosphate infiltrated into the lungs in the form of

Shortwave radiative effects of unactivated aerosol particles in clouds

International Nuclear Information System (INIS)

Ackerman, T.; Baker, M.B.

1977-01-01

Clouds in some polluted areas may contain high concentrations of anthropogenic aerosol particles. The possible role of these particles in perturbing the optical and dynamical properties of the clouds is an important question for climate studies. The direct radiative effects of unactivated aerosol particles in stable stratus clouds have been calculated at lambda=0.5μm. Several simplifying asumptions have been made relating the behavior of such particles in the high humidity enviornment within the cloud to their physicochemical make-up. It is shown that the energy absorbed by particles within the clouds may be, for realistic concentrations, comparable to the latent heat released and thus may play a significant role in cloud dynamics in some areas. These results are shown to be relatively insensitive to the assumptions about the particle properties within the cloud

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.

Determination of Aerosol Particle Diameter Using Cascade Impactor Procedure

International Nuclear Information System (INIS)

Bunawas; Ruslanto, P. O

1998-01-01

Determination of aerosol particle size distribution has been done using a low pressure Andersen's cascade impactor with 13 stages. The aerosol has been sampled with flow rate of aerosol sampling of 28.3 Ipm. Preliminary study result shows that aerosol in the simulation chamber was spread in monomodal distribution with Mass Median Aerodynamic Diameter of 4.9 μm. The aerosol measurement in Japan Power Demonstration Reactor has been spread in trimodal distribution with Activity Median Aerodynamic Diameter equal to 13.3 μm. The use of mylar as impaction plate instead of aluminum foil gives good result

Single-particle characterization of urban aerosol particles collected in three Korean cites using low-Z electron probe X-ray microanalysis.

Science.gov (United States)

Ro, Chul-Un; Kim, HyeKyeong; Oh, Keun-Young; Yea, Sun Kyung; Lee, Chong Bum; Jang, Meongdo; Van Grieken, René

2002-11-15

A recently developed single-particle analytical technique, called low-Z electron probe X-ray microanalysis (low-Z EPMA), was applied to characterize urban aerosol particles collected in three cities of Korea (Seoul, CheongJu, and ChunCheon) on single days in the winter of 1999. In this study, it is clearly demonstrated that the low-Z EPMA technique can provide detailed and quantitative information on the chemical composition of particles in the urban atmosphere. The collected aerosol particles were analyzed and classified on the basis of their chemical species. Various types of particles were identified, such as soil-derived, carbonaceous, marine-originated, and anthropogenic particles. In the sample collected in Seoul, carbonaceous, aluminosilicates, silicon dioxide, and calcium carbonate aerosol particles were abundantly encountered. In the CheongJu and ChunCheon samples, carbonaceous, aluminosilicates, reacted sea salts, and ammonium sulfate aerosol particles were often seen. However, in the CheongJu sample, ammonium sulfate particles were the most abundant in the fine fraction. Also, calcium sulfate and nitrate particles were significantly observed. In the ChunCheon sample, organic particles were the most abundant in the fine fraction. Also, sodium nitrate particles were seen at high levels. The ChunCheon sample seemed to be strongly influenced by sea-salt aerosols originating from the Yellow Sea, which is located about 115 km away from the city.

Gas-to-particle conversion in the atmospheric environment by radiation-induced and photochemical reactions

International Nuclear Information System (INIS)

Vohra, K.G.

1975-01-01

During the last few years a fascinating new area of research involving ionizing radiations and photochemistry in gas-to-particle conversion in the atmosphere has been developing at a rapid pace. Two problems of major interest and concern in which this is of paramount importance are: (1) radiation induced and photochemical aerosol formation in the stratosphere and, (2) role of radiations and photochemistry in smog formation. The peak in cosmic ray intensity and significant solar UV flux in the stratosphere lead to complex variety of reactions involving major and trace constituents in this region of the atmosphere, and some of these reactions are of vital importance in aerosol formation. The problem is of great current interest because the pollutant gases from industrial sources and future SST operations entering the stratosphere could increase the aerosol burden in the stratosphere and affect the solar energy input of the troposphere with consequent ecological and climatic changes. On the other hand, in the nuclear era, the atmospheric releases from reactors and processing plants could lead to changes in the cloud nucleation behaviour of the environment and possible increase in smog formation in the areas with significant levels of radiations and conventional pollutants. A review of the earlier work, current status of the problem, and conventional pollutants. A review of the earlier work, current status of the problem, and some recent results of the experiments conducted in the author's laboratory are presented. The possible mechanisms of gas-to-particle conversion in the atmosphere have been explained

Wintertime water-soluble aerosol composition and particle water content in Fresno, California

Science.gov (United States)

Parworth, Caroline L.; Young, Dominique E.; Kim, Hwajin; Zhang, Xiaolu; Cappa, Christopher D.; Collier, Sonya; Zhang, Qi

2017-03-01

The composition and concentrations of water-soluble gases and ionic aerosol components were measured from January to February 2013 in Fresno, CA, with a particle-into-liquid sampler with ion chromatography and annular denuders. The average (±1σ) ionic aerosol mass concentration was 15.0 (±9.4) µg m-3, and dominated by nitrate (61%), followed by ammonium, sulfate, chloride, potassium, nitrite, and sodium. Aerosol-phase organic acids, including formate and glycolate, and amines including methylaminium, triethanolaminium, ethanolaminium, dimethylaminium, and ethylaminium were also detected. Although the dominant species all came from secondary aerosol formation, there were primary sources of ionic aerosols as well, including biomass burning for potassium and glycolate, sea spray for sodium, chloride, and dimethylamine, and vehicles for formate. Particulate methanesulfonic acid was also detected and mainly associated with terrestrial sources. On average, the molar concentration of ammonia was 49 times greater than nitric acid, indicating that ammonium nitrate formation was limited by nitric acid availability. Particle water was calculated based on the Extended Aerosol Inorganics Model (E-AIM) thermodynamic prediction of inorganic particle water and κ-Köhler theory approximation of organic particle water. The average (±1σ) particle water concentration was 19.2 (±18.6) µg m-3, of which 90% was attributed to inorganic species. The fractional contribution of particle water to total fine particle mass averaged at 36% during this study and was greatest during early morning and night and least during the day. Based on aqueous-phase concentrations of ions calculated by using E-AIM, the average (±1σ) pH of particles in Fresno during the winter was estimated to be 4.2 (±0.2).

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

Ultrasonic-resonator-combined apparatus for purifying nuclear aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Hou, Suxia; Zhang, Quanhu; Li, Sufen; Chen, Chen; Su, Xianghua [Xi' an Hi-Tech Institute, Xi' an (China)

2017-12-15

The radiation hazards of radionuclides in the air arising from the storage room of nuclear devices to the operators cannot be ignored. A new ultrasonic-resonator-combined method for purifying nuclear aerosol particles is introduced. To remove particles with diameters smaller than 0.3 μm, an ultrasonic chamber is induced to agglomerate these submicron particles. An apparatus which is used to purify the nuclear aerosol particles is described in the article. The apparatus consists of four main parts: two filtering systems, an ultrasonic chamber and a high-pressure electrostatic precipitator system. Finally, experimental results demonstrated the effectiveness of the implementation of the ultrasonic resonators. The feasibility of the method is proven by its application to the data analysis of the experiments.

Bounce behavior of freshly nucleated biogenic secondary organic aerosol particles

Directory of Open Access Journals (Sweden)

A. Virtanen

2011-08-01

Full Text Available The assessment of the climatic impacts and adverse health effects of atmospheric aerosol particles requires detailed information on particle properties. However, very limited information is available on the morphology and phase state of secondary organic aerosol (SOA particles. The physical state of particles greatly affects particulate-phase chemical reactions, and thus the growth rates of newly formed atmospheric aerosol. Thus verifying the physical phase state of SOA particles gives new and important insight into their formation, subsequent growth, and consequently potential atmospheric impacts. According to our recent study, biogenic SOA particles produced in laboratory chambers from the oxidation of real plant emissions as well as in ambient boreal forest atmospheres can exist in a solid phase in size range >30 nm. In this paper, we extend previously published results to diameters in the range of 17–30 nm. The physical phase of the particles is studied by investigating particle bounce properties utilizing electrical low pressure impactor (ELPI. We also investigate the effect of estimates of particle density on the interpretation of our bounce observations. According to the results presented in this paper, particle bounce clearly decreases with decreasing particle size in sub 30 nm size range. The comparison measurements by ammonium sulphate and investigation of the particle impaction velocities strongly suggest that the decreasing bounce is caused by the differences in composition and phase of large (diameters greater than 30 nm and smaller (diameters between 17 and 30 nm particles.

Source apportionment of aerosol particles using polycapillary slightly focusing X-ray lens

Energy Technology Data Exchange (ETDEWEB)

Sun Tianxi [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China) and Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China) and Beijing Radiation Center, Beijing 100875 (China)], E-mail: stxbeijing@163.com; Liu Zhiguo [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China) and Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China) and Beijing Radiation Center, Beijing 100875 (China)], E-mail: liuzgbeijing@163.com; Zhu Guanghua; Liu Hui [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Xu Qing [Institute of High Energy Physics, Chinese Academy of Science, Beijing 100039 (China); Li Yude; Wang Guangpu; Luo Ping; Pan Qiuli; Ding Xunliang [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

2009-06-11

A micro-X-ray fluorescence (Micro-XRF) spectrometer based on a polycapillary slightly focusing X-ray lens (PSFXRL) and laboratory X-ray source was designed to carry out the source apportionment of aerosol particles. In the distribution curve of the X-ray intensity in the focal spot of PSFXRL, there was a plateau with a diameter of about 65 {mu}m. The uniformity of this plateau was about 3%. This was helpful in measuring the XRF spectrum of a single aerosol particle in which the element distributions are not uniform. The minimum detection limit (MDL) of this Micro-XRF spectrometer was 15 ppm for the Fe-K{sub {alpha}}. The origins of the aerosol particles at the exit of a subway station and a construction site were apportioned. This Micro-XRF spectrometer has potential applications in analysis of single aerosol particles.

Deposition of aerosol particles in bent pipe

International Nuclear Information System (INIS)

Matsui, Hiroshi; Ohhata, Tsutomu

1989-01-01

An equation to estimate deposition fraction of aerosol particles in a bent pipe is derived and the validity is verified experimentally. The equation is obtained by assuming that the resultant acceleration of the gravity and the centrifugal force induced in the bend acts on the aerosol particles, and is found to give a relatively accurate estimation of the deposition fraction if a certain correction factor is introduced to the equation. The deposition fraction has a minimum against Reynold number, and the deposition due to centrifugal force dominates at greater Reynolds number than that at the minimum deposition fraction. On the other hand, the smaller the radius of curvature of the bend is, the larger the deposition fraction due to the centrifugal force is. (author)

Novel Measurements of Aerosol Particle Interfaces Using Biphasic Microfluidics

Science.gov (United States)

Metcalf, A. R.; Dutcher, C. S.

2014-12-01

Secondary organic aerosol (SOA) particles are nearly ubiquitous in the atmosphere and yet there remains large uncertainties in their formation processes and ambient properties. These particles are complex microenvironments, which can contain multiple interfaces due to internal aqueous-organic phase partitioning and to the external liquid-vapor surface. These aerosol interfaces can profoundly affect the fate of condensable organic compounds emitted into the atmosphere by altering the way in which organic vapors interact with the ambient aerosol. Aerosol interfaces affect particle internal structure, species uptake, equilibrium partitioning, activation to cloud condensation or ice nuclei, and optical properties. For example, organic thin films can shield the core of the aerosol from the ambient environment, which may disrupt equilibrium partitioning and mass transfer. To improve our ability to accurately predict the fate of SOA in the atmosphere, we must improve our knowledge of aerosol interfaces and their interactions with the ambient environment. Few technologies exist to accurately probe aerosol interfaces at atmospherically-relevant conditions. In this talk, a novel method using biphasic microscale flows will be introduced for generating, trapping, and perturbing complex interfaces at atmospherically relevant conditions. These microfluidic experiments utilize high-speed imaging to monitor interfacial phenomena at the microscale and are performed with phase contrast and fluorescence microscopy on a temperature-controlled inverted microscope stage. From these experiments, interfacial thermodynamic properties such as surface tension, rheological properties such as interfacial moduli, and kinetic properties such as mass transfer coefficients can be measured or inferred. Chemical compositions of the liquid phases studied here span a range of viscosities and include electrolyte and water soluble organic acid species often observed in the atmosphere, such as mixtures

Real-time measurement of aerosol particle concentration at high temperatures; Hiukkaspitoisuuden reaaliaikainen mittaaminen korkeassa laempoetilassa

Energy Technology Data Exchange (ETDEWEB)

Keskinen, J; Hautanen, J; Laitinen, A [Tampere Univ. of Technology (Finland). Physics

1997-10-01

The aim of this project is to develop a new method for continuous aerosol particle concentration measurement at elevated temperatures (up to 800-1000 deg C). The measured property of the aerosol particles is the so called Fuchs surface area. This quantity is relevant for diffusion limited mass transfer to particles. The principle of the method is as follows. First, aerosol particles are charged electrically by diffusion charging process. The charging takes place at high temperature. After the charging, aerosol is diluted and cooled. Finally, aerosol particles are collected and the total charge carried by the aerosol particles is measured. Particle collection and charge measurement take place at low temperature. Benefits of this measurement method are: particles are charged in-situ, charge of the particles is not affected by the temperature and pressure changes after sampling, particle collection and charge measurement are carried out outside the process conditions, and the measured quantity is well defined. The results of this study can be used when the formation of the fly ash particles is studied. Another field of applications is the study and the development of gasification processes. Possibly, the method can also be used for the monitoring the operation of the high temperature particle collection devices. (orig.)

Size measurement of radioactive aerosol particles in intense radiation fields using wire screens and imaging plates

Energy Technology Data Exchange (ETDEWEB)

Oki, Yuichi; Tanaka, Toru; Takamiya, Koichi; Ishi, Yoshihiro; UesugI, Tomonori; Kuriyama, Yasutoshi; Sakamoto, Masaaki; Ohtsuki, Tsutomu [Kyoto University Research Reactor Institute, Osaka (Japan); Nitta, Shinnosuke [Graduate School of Engineering, Kyoto University, Kyoto (Japan); Osada, Naoyuki [Advanced Science Research Center, Okayama University, Okayama (Japan)

2016-09-15

Very fine radiation-induced aerosol particles are produced in intense radiation fields, such as high-intensity accelerator rooms and containment vessels such as those in the Fukushima Daiichi nuclear power plant (FDNPP). Size measurement of the aerosol particles is very important for understanding the behavior of radioactive aerosols released in the FDNPP accident and radiation safety in high-energy accelerators. A combined technique using wire screens and imaging plates was developed for size measurement of fine radioactive aerosol particles smaller than 100 nm in diameter. This technique was applied to the radiation field of a proton accelerator room, in which radioactive atoms produced in air during machine operation are incorporated into radiation-induced aerosol particles. The size of 11C-bearing aerosol particles was analyzed using the wire screen technique in distinction from other positron emitters in combination with a radioactive decay analysis. The size distribution for 11C-bearing aerosol particles was found to be ca. 70 μm in geometric mean diameter. The size was similar to that for 7Be-bearing particles obtained by a Ge detector measurement, and was slightly larger than the number-based size distribution measured with a scanning mobility particle sizer. The particle size measuring method using wire screens and imaging plates was successfully applied to the fine aerosol particles produced in an intense radiation field of a proton accelerator. This technique is applicable to size measurement of radioactive aerosol particles produced in the intense radiation fields of radiation facilities.

Elucidating determinants of aerosol composition through particle-type-based receptor modeling

Science.gov (United States)

McGuire, M. L.; Jeong, C.-H.; Slowik, J. G.; Chang, R. Y.-W.; Corbin, J. C.; Lu, G.; Mihele, C.; Rehbein, P. J. G.; Sills, D. M. L.; Abbatt, J. P. D.; Brook, J. R.; Evans, G. J.

2011-08-01

An aerosol time-of-flight mass spectrometer (ATOFMS) was deployed at a semi-rural site in southern Ontario to characterize the size and chemical composition of individual particles. Particle-type-based receptor modelling of these data was used to investigate the determinants of aerosol chemical composition in this region. Individual particles were classified into particle-types and positive matrix factorization (PMF) was applied to their temporal trends to separate and cross-apportion particle-types to factors. The extent of chemical processing for each factor was assessed by evaluating the internal and external mixing state of the characteristic particle-types. The nine factors identified helped to elucidate the coupled interactions of these determinants. Nitrate-laden dust was found to be the dominant type of locally emitted particles measured by ATOFMS. Several factors associated with aerosol transported to the site from intermediate local-to-regional distances were identified: the Organic factor was associated with a combustion source to the north-west; the ECOC Day factor was characterized by nearby local-to-regional carbonaceous emissions transported from the south-west during the daytime; and the Fireworks factor consisted of pyrotechnic particles from the Detroit region following holiday fireworks displays. Regional aerosol from farther emissions sources was reflected through three factors: two Biomass Burning factors and a highly chemically processed Long Range Transport factor. The Biomass Burning factors were separated by PMF due to differences in chemical processing which were in part elucidated by the passage of two thunderstorm gust fronts with different air mass histories. The remaining two factors, ECOC Night and Nitrate Background, represented the night-time partitioning of nitrate to pre-existing particles of different origins. The distinct meteorological conditions observed during this month-long study in the summer of 2007 provided a unique

Carbonaceous aerosol particles from common vegetation in the Grand Canyon

International Nuclear Information System (INIS)

Hallock, K.A.; Mazurek, M.A.; Cass, G.R.

1992-05-01

The problem of visibility reduction in the Grand Canyon due to fine organic aerosol particles in the atmosphere has become an area of increased environmental concern. Aerosol particles can be derived from many emission sources. In this report, we focus on identifying organic aerosols derived from common vegetation in the Grand Canyon. These aerosols are expected to be significant contributors to the total atmospheric organic aerosol content. Aerosol samples from living vegetation were collected by resuspension of surface wax and resin components liberated from the leaves of vegetation common to areas of the Grand Canyon. The samples were analyzed using high-resolution gas chromatography/mass spectrometry (GC/MS). Probable identification of compounds was made by comparison of sample spectra with National Institute of Standards and Technology (NIST) mass spectral references and positive identification of compounds was made when possible by comparison with authentic standards as well as NIST references. Using these references, we have been able to positively identify the presence of n-alkane and n-alkanoic acid homolog series in the surface waxes of the vegetation sampled. Several monoterpenes, sesquiterpenes, and diterpenes were identified also as possible biogenic aerosols which may contribute to the total organic aerosol abundance leading to visibility reduction in the Grand Canyon

Influence of particle size and chemistry on the cloud nucleating properties of aerosols

Directory of Open Access Journals (Sweden)

P. K. Quinn

2008-02-01

Full Text Available The ability of an aerosol particle to act as a cloud condensation nuclei (CCN is a function of the size of the particle, its composition and mixing state, and the supersaturation of the cloud. In-situ data from field studies provide a means to assess the relative importance of these parameters. During the 2006 Texas Air Quality – Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS-GoMACCS, the NOAA RV Ronald H. Brown encountered a wide variety of aerosol types ranging from marine near the Florida panhandle to urban and industrial in the Houston-Galveston area. These varied sources provided an opportunity to investigate the role of aerosol sources and chemistry in the potential activation of particles to form cloud droplets. Measurements were made of CCN concentrations, aerosol chemical composition in the size range relevant for particle activation in warm clouds, and aerosol size distributions. Variability in aerosol composition was parameterized by the mass fraction of Hydrocarbon-like Organic Aerosol (HOA for particle diameters less than 200 nm (vacuum aerodynamic. The HOA mass fraction in this size range was lowest for marine aerosol and highest for aerosol sampled close to anthropogenic sources. Combining all data from the experiment reveals that composition (defined by HOA mass fraction explains 40% of the variance in the critical diameter for particle activation at the instrumental supersaturation (S of 0.44%. Correlations between HOA mass fraction and aerosol mean diameter show that these two parameters are essentially independent of one another for this data set. We conclude that, based on the variability of the HOA mass fraction observed during TexAQS-GoMACCS, variability in particle composition played a significant role in determining the fraction of particles that could activate to form cloud droplets. Using a simple model based on Köhler theory and the assumption that HOA is insoluble, we estimate the

Number concentrations of solid particles from the spinning top aerosol generator

International Nuclear Information System (INIS)

Mitchell, J.P.

1983-02-01

A spinning top aerosol generator has been used to generate monodisperse methylene blue particles in the size range from 0.6 to 6 μm. The number concentrations of these aerosols have been determined by means of an optical particle counter and compared with the equivalent measurements obtained by filter collection and microscopy. (author)

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)

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.

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.

The formation of aerosol particles during combustion of biomass and waste. Final report

Energy Technology Data Exchange (ETDEWEB)

Hjerrild Zeuthen, J

2007-05-15

This thesis describes the formation of aerosol particles during combustion of biomass and waste. The formation of aerosol particles is investigated by studying condensation of alkali salts from synthetic flue gasses in a laboratory tubular furnace. In this so-called laminar flow aerosol condenser-furnace gaseous alkali chlorides are mixed with sulphur dioxide, water vapour and oxygen. At high temperatures the alkali chloride reacts with sulphur dioxide to form alkali sulphate. During subsequent cooling of the synthetic flue gas the chlorides and sulphates condense either as deposits on walls or on other particles or directly from the gas phase by homogenous nucleation. A previously developed computer code for simulation of one-component nucleation of particles in a cylindrical laminar flow is extended to include a homogeneous gas phase reaction to produce gaseous alkali sulphate. The formation of aerosol particles during full-scale combustion of wheat straw is investigated in a 100 MW grate-fired boiler. Finally, aerosols from incineration of waste are investigated during full-scale combustion of municipal waste in a 22 MW grate-fired unit. (BA)

Prospects of real-time single-particle biological aerosol analysis: A comparison between laser-induced breakdown spectroscopy and aerosol time-of-flight mass spectrometry

International Nuclear Information System (INIS)

Beddows, D.C.S.; Telle, H.H.

2005-01-01

In this paper we discuss the prospects of real-time, in situ laser-induced breakdown spectroscopy applied for the identification and classification of bio-aerosols (including species of potential bio-hazard) within common urban aerosol mixtures. In particular, we address the issues associated with the picking out of bio-aerosols against common background aerosol particles, comparing laser-induced breakdown spectroscopy measurements with data from a mobile single-particle aerosol mass spectrometer (ATOFMS). The data from the latter provide statistical data over an extended period of time, highlighting the variation of the background composition. While single-particle bio-aerosols are detectable in principle, potential problems with small (∼ 1 μm size) bio-aerosols have been identified; constituents of the air mass other than background aerosols, e.g. gaseous CO 2 in conjunction with common background aerosols, may prevent unique recognition of the bio-particles. We discuss whether it is likely that laser-induced breakdown spectroscopy on its own can provide reliable, real-time identification of bio-aerosol in an urban environment, and it is suggested that more than one technique should be or would have to be used. A case for using a combination of laser-induced breakdown spectroscopy and Raman (and/or) laser-induced fluorescence spectroscopy is made

Diurnal Cycles of Aerosol Optical Properties at Pico Tres Padres, Mexico City: Evidences for Changes in Particle Morphology and Secondary Aerosol Formation

Science.gov (United States)

Mazzoleni, C.; Dubey, M.; Chakrabarty, R.; Moosmuller, H.; Onasch, T.; Zavala, M.; Herndon, S.; Kolb, C.

2007-12-01

Aerosol optical properties affect planetary radiative balance and depend on chemical composition, size distribution, and morphology. During the MILAGRO field campaign, we measured aerosol absorption and scattering in Mexico City using the Los Alamos aerosol photoacoustic (LAPA) instrument operating at 781 nm. The LAPA was mounted on-board the Aerodyne Research Inc. mobile laboratory, which hosted a variety of gaseous and aerosol instruments. During the campaign, the laboratory was moved to different sites, capturing spatial and temporal variability. Additionally, we collected ambient aerosols on Nuclepore filters for scanning electron microscopy (SEM) analysis. SEM images of selected filters were taken to study particle morphology. Between March 7th and 19th air was sampled at the top of Pico Tres Padres, a mountain on the north side of Mexico City. Aerosol absorption and scattering followed diurnal patterns related to boundary layer height and solar insulation. We report an analysis of aerosol absorption, scattering, and morphology for three days (9th, 11th and 12th of March 2006). The single scattering albedo (SSA, ratio of scattering to total extinction) showed a drop in the tens-of-minutes-to-hour time frame after the boundary layer grew above the sampling site. Later in the day the SSA rose steadily reaching a maximum in the afternoon. The SEM images showed a variety of aerosol shapes including fractal-like aggregates, spherical particles, and other shapes. The absorption correlated with the CO2 signal and qualitatively with the fraction of fractal-like particles to the total particle count. In the afternoon the SSA qualitatively correlated with a relative increase in spherical particles and total particle count. These observed changes in optical properties and morphology can be explained by the dominant contribution of freshly emitted particles in the morning and by secondary particle formation in the afternoon. SSA hourly averaged values ranged from ~0.63 in

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

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.

On the sources of submicron aerosol particles in savannah: implications for climate and air quality

Energy Technology Data Exchange (ETDEWEB)

Vakkari, V.

2013-11-01

Aerosol is defined as solid or liquid particles suspended in a gas lighter than the particles, which means that the atmosphere we live in is an aerosol in itself. Although aerosol particles are only a trace component of the atmosphere they affect our lives in several ways. The aerosol particles can cause adverse health effects and deteriorate visibility, but they affect also the Earth s climate directly by scattering and absorbing solar radiation and indirectly by modulating the properties of the clouds. Anthropogenic aerosol particles have a net cooling effect on the climate, but the uncertainty in the amount of cooling is presently as large as the heating effect of carbon dioxide. To reduce the uncertainty in the aerosol climate effects, spatially representative reference data of high quality are needed for the global climate models. To be able to capture the diurnal and seasonal variability the data have to be collected continuously over time periods that cover at least one full seasonal cycle. Until recently such data have been nearly non-existing for continental Africa and hence one aim of this work was to establish a permanent measurement station measuring the key aerosol particle properties in a continental location in southern Africa. In close collaboration with the North-West University in South Africa this aim has now been achieved at the Welgegund measurement station. The other aims of this work were to determine the aerosol particle concentrations including their seasonal and diurnal variation and to study the most important aerosol particle sources in continental southern Africa. In this thesis the aerosol size distribution and its seasonal and diurnal variation is reported for different environments ranging from a clean rural background to an anthropogenically heavily influenced mining region in continental southern Africa. Atmospheric regional scale new particle formation has been observed at a world record high frequency and it dominates the diurnal

Interpretation of aerosol trace metal particle size distributions

International Nuclear Information System (INIS)

Johansson, T.B.; Van Grieken, R.E.; Winchester, J.W.

1974-01-01

Proton-induced X-ray emission (PIXE) analysis is capable of rapid routine determination of 10--15 elements present in amounts greater than or equal to 1 ng simultaneously in aerosol size fractions as collected by single orifice impactors over short periods of time. This enables detailed study of complex relationships between elements detected. Since absolute elemental concentrations may be strongly influenced by meteorological and topographical conditions, it is useful to normalize to a reference element. Comparison between the ratios of concentrations with aerosol and corresponding values for anticipated sources may lead to the identification of important sources for the elements. Further geochemical insights may be found through linear correlation coefficients, regression analysis, and cluster analysis. By calculating correlations for elemental pairs, an indication of the degree of covariance between the elements is obtained. Preliminary results indicate that correlations may be particle size dependent. A high degree of covariance may be caused either by a common source or may only reflect the conservative nature of the aerosol. In a regression analysis, by plotting elemental pairs and estimating the regression coefficients, we may be able to conclude if there is more than one source operating for a given element in a certain size range. Analysis of clustering of several elements, previously investigated for aerosol filter samples, can be applied to the analysis of aerosol size fractions. Careful statistical treatment of elemental concentrations as a function of aerosol particle size may thus yield significant information on the generation, transport and deposition of trace metals in the atmosphere

Real-time aerosol photometer and optical particle counter comparison

International Nuclear Information System (INIS)

Santi, E.; Belosi, F.; Santachiara, G.; Prodi, F.; Berico, M.

2010-01-01

The paper presents the results of a comparison exercise among real-time aerosol samplers, based on different light scattering techniques. The comparison was carried out near to the ISAC institute in a box positioned inside the CNR research area in Bologna. Two nephelometers (Dust Trak from TSI, and Air Genius from Unitec) and an optical particle counter (ENVIRO-check from Grimm) were used for P M1 and P M10 fraction assessment. In the case of the optical particle counter, the particle number concentration in each size bin was also used. In parallel, two manual sampling lines were employed for reference (gravimetric) measurements. The results highlight different factor scales for the dust monitors, in comparison with gravimetric assessment, underlining the importance of a user calibration of such monitors as a function of the specific aerosol sampled. Moreover, the relative fluctuations of the hourly P M 10 and P M1 concentrations, against daily average concentrations, were studied in order to compare the ability of each sampler to follow changes in the aerosol size distribution. It was found that the photometers and optical particle counter revealed different behaviours. In the latter, a small increase in the particle concentration number in the coarse fraction gave a relatively high increase in the mass concentration that was not measured by the photometers. The explanation could be the relatively slight influence of a small particle number variation on the total scattered light for the photometers, unlike the case of the optical particle counter, where each particle contributes to the mass concentration. This aspect merits future research in order to better understand optical particle counter output used in P Mx monitoring activities.

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.

Electron mean free path from angle-dependent photoelectron spectroscopy of aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Goldmann, Maximilian; Miguel-Sánchez, Javier; West, Adam H. C.; Yoder, Bruce L.; Signorell, Ruth, E-mail: rsignorell@ethz.ch [Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich (Switzerland)

2015-06-14

We propose angle-resolved photoelectron spectroscopy of aerosol particles as an alternative way to determine the electron mean free path of low energy electrons in solid and liquid materials. The mean free path is obtained from fits of simulated photoemission images to experimental ones over a broad range of different aerosol particle sizes. The principal advantage of the aerosol approach is twofold. First, aerosol photoemission studies can be performed for many different materials, including liquids. Second, the size-dependent anisotropy of the photoelectrons can be exploited in addition to size-dependent changes in their kinetic energy. These finite size effects depend in different ways on the mean free path and thus provide more information on the mean free path than corresponding liquid jet, thin film, or bulk data. The present contribution is a proof of principle employing a simple model for the photoemission of electrons and preliminary experimental data for potassium chloride aerosol particles.

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.

Oxalate metal complexes in aerosol particles: implications for the hygroscopicity of oxalate-containing particles

Directory of Open Access Journals (Sweden)

T. Furukawa

2011-05-01

Full Text Available Atmospheric aerosols have both a direct and an indirect cooling effect that influences the radiative balance at the Earth's surface. It has been estimated that the degree of cooling is large enough to weaken the warming effect of carbon dioxide. Among the cooling factors, secondary organic aerosols (SOA play an important role in the solar radiation balance in the troposphere as SOA can act as cloud condensation nuclei (CCN and extend the lifespan of clouds because of their high hygroscopic and water soluble nature. Oxalic acid is an important component of SOA, and is produced via several formation pathways in the atmosphere. However, it is not certain whether oxalic acid exists as free oxalic acid or as metal oxalate complexes in aerosols, although there is a marked difference in their solubility in water and their hygroscopicity. We employed X-ray absorption fine structure spectroscopy to characterize the calcium (Ca and zinc (Zn in aerosols collected at Tsukuba in Japan. Size-fractionated aerosol samples were collected for this purpose using an impactor aerosol sampler. It was shown that 10–60% and 20–100% of the total Ca and Zn in the finer particles (<2.1 μm were present as Ca and Zn oxalate complexes, respectively. Oxalic acid is hygroscopic and can thus increase the CCN activity of aerosol particles, while complexes with various polyvalent metal ions such as Ca and Zn are not hygroscopic, which cannot contribute to the increase of the CCN activity of aerosols. Based on the concentrations of noncomplexed and metal-complexed oxalate species, we found that most of the oxalic acid is present as metal oxalate complexes in the aerosols, suggesting that oxalic acid does not always increase the hygroscopicity of aerosols in the atmosphere. Similar results are expected for other dicarboxylic acids, such as malonic and succinic acids. Thus, it is advisable that the cooling effect of organic aerosols should be estimated by including the

Particle size of radioactive aerosols generated during machine operation in high-energy proton accelerators

International Nuclear Information System (INIS)

Oki, Yuichi; Kanda, Yukio; Kondo, Kenjiro; Endo, Akira

2000-01-01

In high-energy accelerators, non-radioactive aerosols are abundantly generated due to high radiation doses during machine operation. Under such a condition, radioactive atoms, which are produced through various nuclear reactions in the air of accelerator tunnels, form radioactive aerosols. These aerosols might be inhaled by workers who enter the tunnel just after the beam stop. Their particle size is very important information for estimation of internal exposure doses. In this work, focusing on typical radionuclides such as 7 Be and 24 Na, their particle size distributions are studied. An aluminum chamber was placed in the EP2 beam line of the 12-GeV proton synchrotron at High Energy Accelerator Research Organization (KEK). Aerosol-free air was introduced to the chamber, and aerosols formed in the chamber were sampled during machine operation. A screen-type diffusion battery was employed in the aerosol-size analysis. Assuming that the aerosols have log-normal size distributions, their size distributions were obtained from the radioactivity concentrations at the entrance and exit of the diffusion battery. Radioactivity of the aerosols was measured with Ge detector system, and concentrations of non-radioactive aerosols were obtained using condensation particle counter (CPC). The aerosol size (radius) for 7 Be and 24 Na was found to be 0.01-0.04 μm, and was always larger than that for non-radioactive aerosols. The concentration of non-radioactive aerosols was found to be 10 6 - 10 7 particles/cm 3 . The size for radioactive aerosols was much smaller than ordinary atmospheric aerosols. Internal doses due to inhalation of the radioactive aerosols were estimated, based on the respiratory tract model of ICRP Pub. 66. (author)

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)

Improved identification of primary biological aerosol particles using single-particle mass spectrometry

Directory of Open Access Journals (Sweden)

M. A. Zawadowicz

2017-06-01

Full Text Available Measurements of primary biological aerosol particles (PBAP, especially at altitudes relevant to cloud formation, are scarce. Single-particle mass spectrometry (SPMS has been used to probe aerosol chemical composition from ground and aircraft for over 20 years. Here we develop a method for identifying bioaerosols (PBAP and particles containing fragments of PBAP as part of an internal mixture using SPMS. We show that identification of bioaerosol using SPMS is complicated because phosphorus-bearing mineral dust and phosphorus-rich combustion by-products such as fly ash produce mass spectra with peaks similar to those typically used as markers for bioaerosol. We have developed a methodology to differentiate and identify bioaerosol using machine learning statistical techniques applied to mass spectra of known particle types. This improved method provides far fewer false positives compared to approaches reported in the literature. The new method was then applied to two sets of ambient data collected at Storm Peak Laboratory and a forested site in Central Valley, California to show that 0.04–2 % of particles in the 200–3000 nm aerodynamic diameter range were identified as bioaerosol. In addition, 36–56 % of particles identified as biological also contained spectral features consistent with mineral dust, suggesting internal dust–biological mixtures.

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

Spatial Variability of CCN Sized Aerosol Particles

Science.gov (United States)

Asmi, A.; Väänänen, R.

2014-12-01

The computational limitations restrict the grid size used in GCM models, and for many cloud types they are too large when compared to the scale of the cloud formation processes. Several parameterizations for e.g. convective cloud formation exist, but information on spatial subgrid variation of the cloud condensation nuclei (CCNs) sized aerosol concentration is not known. We quantify this variation as a function of the spatial scale by using datasets from airborne aerosol measurement campaigns around the world including EUCAARI LONGREX, ATAR, INCA, INDOEX, CLAIRE, PEGASOS and several regional airborne campaigns in Finland. The typical shapes of the distributions are analyzed. When possible, we use information obtained by CCN counters. In some other cases, we use particle size distribution measured by for example SMPS to get approximated CCN concentration. Other instruments used include optical particle counters or condensational particle counters. When using the GCM models, the CCN concentration used for each the grid-box is often considered to be either flat, or as an arithmetic mean of the concentration inside the grid-box. However, the aircraft data shows that the concentration values are often lognormal distributed. This, combined with the subgrid variations in the land use and atmospheric properties, might cause that the aerosol-cloud interactions calculated by using mean values to vary significantly from the true effects both temporary and spatially. This, in turn, can cause non-linear bias into the GCMs. We calculate the CCN aerosol concentration distribution as a function of different spatial scales. The measurements allow us to study the variation of these distributions within from hundreds of meters up to hundreds of kilometers. This is used to quantify the potential error when mean values are used in GCMs.

Characterization of aerosol particles from grass mowing by joint deployment of ToF-AMS and ATOFMS instruments

Science.gov (United States)

Drewnick, Frank; Dall'Osto, Manuel; Harrison, Roy

During a measurement campaign at a semi-urban/industrial site a grass-cutting event was observed, when the lawn in the immediate surrounding of the measurement site was mowed. Using a wide variety of state-of-the-art aerosol measurement technology allowed a broad characterization of the aerosol generated by the lawn mowing. The instrumentation included two on-line aerosol mass spectrometers: an Aerodyne Time-of-Flight Aerosol Mass Spectrometer (ToF-AMS) and a TSI Aerosol Time-of-Flight Mass Spectrometer (ATOFMS); in addition, a selection of on-line aerosol concentration and size distribution instruments (OPC, APS, SMPS, CPC, FDMS-TEOM, MAAP) was deployed. From comparison of background aerosol measurements during most of the day with the aerosol measured during the lawn mowing, the grass cutting was found to generate mainly two different types of aerosol particles: an intense ultrafine particle mode (1 h average: 4 μg m -3) of almost pure hydrocarbon-like organics and a distinct particle mode in the upper sub-micrometer size range containing particles with potassium and nitrogen-organic compounds. The ultrafine particles are probably lubricating oil particles from the lawn mower exhaust; the larger particles are swirled-up plant debris particles from the mowing process. While these particle types were identified in the data from the two mass spectrometers, the on-line aerosol concentration and size distribution data support these findings. The results presented here show that the combination of quantitative aerosol particle ensemble mass spectrometry (ToF-AMS) and single particle mass spectrometry (ATOFMS) provides much deeper insights into the nature of the aerosol properties than each of the instruments could do alone. Therefore a combined deployment of both types of instruments is strongly recommended.

Algorithm of Data Reduce in Determination of Aerosol Particle Size Distribution at Damps/C

International Nuclear Information System (INIS)

Muhammad-Priyatna; Otto-Pribadi-Ruslanto

2001-01-01

The analysis had to do for algorithm of data reduction on Damps/C (Differential Mobility Particle Sizer with Condensation Particle Counter) system, this is for determine aerosol particle size distribution with range 0,01 μm to 1 μm in diameter. Damps/C (Differential Mobility Particle Sizer with Condensation Particle Counter) system contents are software and hardware. The hardware used determine of mobilities of aerosol particle and so the software used determine aerosol particle size distribution in diameter. The mobilities and diameter particle had connection in the electricity field. That is basic program for reduction of data and particle size conversion from particle mobility become particle diameter. The analysis to get transfer function value, Ω, is 0.5. The data reduction program to do conversation mobility basis become diameter basis with number efficiency correction, transfer function value, and poly charge particle. (author)

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.;

AEROSOL PARTICLE COLLECTOR DESIGN STUDY

Energy Technology Data Exchange (ETDEWEB)

Lee, S; Richard Dimenna, R

2007-09-27

A computational evaluation of a particle collector design was performed to evaluate the behavior of aerosol particles in a fast flowing gas stream. The objective of the work was to improve the collection efficiency of the device while maintaining a minimum specified air throughput, nominal collector size, and minimal power requirements. The impact of a range of parameters was considered subject to constraints on gas flow rate, overall collector dimensions, and power limitations. Potential improvements were identified, some of which have already been implemented. Other more complex changes were identified and are described here for further consideration. In addition, fruitful areas for further study are proposed.

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.

Inside versus Outside: Ion Redistribution in Nitric Acid Reacted Sea Spray Aerosol Particles as Determined by Single Particle Analysis (Invited)

Science.gov (United States)

Ault, A. P.; Guasco, T.; Ryder, O. S.; Baltrusaitis, J.; Cuadra-Rodriguez, L. A.; Collins, D. B.; Ruppel, M. J.; Bertram, T. H.; Prather, K. A.; Grassian, V. H.

2013-12-01

Sea spray aerosol (SSA) particles were generated under real-world conditions using natural seawater and a unique ocean-atmosphere facility equipped with actual breaking waves or a marine aerosol reference tank (MART) that replicates those conditions. The SSA particles were exposed to nitric acid in situ in a flow tube and the well-known chloride displacement and nitrate formation reaction was observed. However, as discussed here, little is known about how this anion displacement reaction affects the distribution of cations and other chemical constituents within and phase state of individual SSA particles. Single particle analysis of individual SSA particles shows that cations (Na+, K+, Mg2+ and Ca2+) within individual particles undergo a spatial redistribution after heterogeneous reaction with nitric acid, along with a more concentrated layer of organic matter at the surface of the particle. These data suggest that specific ion and aerosol pH effects play an important role in aerosol particle structure in ways that have not been previously recognized. The ordering of organic coatings can impact trace gas uptake, and subsequently impact trace gas budgets of O3 and NOx.

Wintertime hygroscopicity and volatility of ambient urban aerosol particles

Science.gov (United States)

Enroth, Joonas; Mikkilä, Jyri; Németh, Zoltán; Kulmala, Markku; Salma, Imre

2018-04-01

Hygroscopic and volatile properties of atmospheric aerosol particles with dry diameters of (20), 50, 75, 110 and 145 nm were determined in situ by using a volatility-hygroscopicity tandem differential mobility analyser (VH-TDMA) system with a relative humidity of 90 % and denuding temperature of 270 °C in central Budapest during 2 months in winter 2014-2015. The probability density function of the hygroscopic growth factor (HGF) showed a distinct bimodal distribution. One of the modes was characterised by an overall mean HGF of approximately 1.07 (this corresponds to a hygroscopicity parameter κ of 0.033) independently of the particle size and was assigned to nearly hydrophobic (NH) particles. Its mean particle number fraction was large, and it decreased monotonically from 69 to 41 % with particle diameter. The other mode showed a mean HGF increasing slightly from 1.31 to 1.38 (κ values from 0.186 to 0.196) with particle diameter, and it was attributed to less hygroscopic (LH) particles. The mode with more hygroscopic particles was not identified. The probability density function of the volatility GF (VGF) also exhibited a distinct bimodal distribution with an overall mean VGF of approximately 0.96 independently of the particle size, and with another mean VGF increasing from 0.49 to 0.55 with particle diameter. The two modes were associated with less volatile (LV) and volatile (V) particles. The mean particle number fraction for the LV mode decreased from 34 to 21 % with particle diameter. The bimodal distributions indicated that the urban atmospheric aerosol contained an external mixture of particles with a diverse chemical composition. Particles corresponding to the NH and LV modes were assigned mainly to freshly emitted combustion particles, more specifically to vehicle emissions consisting of large mass fractions of soot likely coated with or containing some water-insoluble organic compounds such as non-hygroscopic hydrocarbon-like organics. The hygroscopic

Measurements of phoretic velocities of aerosol particles in microgravity conditions

Science.gov (United States)

Prodi, F.; Santachiara, G.; Travaini, S.; Vedernikov, A.; Dubois, F.; Minetti, C.; Legros, J. C.

2006-11-01

Measurements of thermo- and diffusio-phoretic velocities of aerosol particles (carnauba wax, paraffin and sodium chloride) were performed in microgravity conditions (Drop Tower facility, in Bremen, and Parabolic Flights, in Bordeaux). In the case of thermophoresis, a temperature gradient was obtained by heating the upper plate of the cell, while the lower one was maintained at environmental temperature. For diffusiophoresis, the water vapour gradient was obtained with sintered plates imbued with a water solution of MgCl 2 and distilled water, at the top and at the bottom of the cell, respectively. Aerosol particles were observed through a digital holographic velocimeter, a device allowing the determination of 3-D coordinates of particles from the observed volume. Particle trajectories and consequently particle velocities were reconstructed through the analysis of the sequence of particle positions. The experimental values of reduced thermophoretic velocities are between the theoretical values of Yamamoto and Ishihara [Yamamoto, K., Ishihara, Y., 1988. Thermophoresis of a spherical particle in a rarefied gas of a transition regime. Phys. Fluids. 31, 3618-3624] and Talbot et al. [Talbot, L., Cheng, R.K., Schefer, R.W., Willis, D.R., 1980. Thermophoresis of particles in a heated boundary layer. J. Fluid Mech. 101, 737-758], and do not show a clear dependence on the thermal conductivity of the aerosol. The existence of negative thermophoresis is not confirmed in our experiments. Concerning diffusiophoretic experiments, the results obtained show a small increase of reduced diffusiophoretic velocity with the Knudsen number.

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

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.

Aerosol vertical distribution, new particle formation, and jet aircraft particle emissions in the free troposhere and tropopause region; Vertikalverteilung und Neubildungsprozesse des Aerosols und partikelfoermige Flugzeugemissionen in der freien Troposphaere und Tropopausenregion

Energy Technology Data Exchange (ETDEWEB)

Schroeder, F P

2000-07-01

A contribution to the understanding of natural and anthropogenously induced particle formation as well as aerosol physical transformation processes within the free troposphere (FT) is introduced. Documentation and interpretation of empirical data relevant with respect to possible climatologic impact of anthropogenous aerosol emissions into the atmosphere is presented. The first section describes new technique for high spatial resolution measurements of ultrafine aerosol particles by condensation nucleus counters (CNCs), a necessary prerequisite for the observation of natural particle formation and jet aircraft emissions. The second section illustrates vertical distribution and variability ranges of the aerosol in the FT and the tropopause region (TP). Typical microphysical states of the atmospheric aerosol within the Northern Hemisphere are documented by means of systematic measurements during more than 60 flight missions. Simple mathematical parameterizations of the aerosol vertical distribution and aerosol size distributions are developed. Important aerosol sources within the FT are localized and possible aerosol formation processes are discussed. The third section is focussed on jet-engine particle emissions within the FT and TP. A unique inflight experiment for detection of extremely high concentrations (>10{sup 6} cm{sup -3}) of extremely small (donw to <3 nm) aerosols inside the exhaust plumes of several jet aircraft is described. Particle emission indices and emission-controlling parameters are deduced. Most important topic is the impact of fuel sulfur content of kerosine on number, size and chemical composition of jet particle emissions. Generalized results are parameterized in form of lognormal aerosol particle size distributions. (orig.) [German] Ein Beitrag zum Verstaendnis natuerlicher und anthropogen induzierter Aerosolneubildung sowie physikalischer Aerosolumwandlung in der freien Troposphaere wird vorgestellt. Empirisch gewonnenes Datenmaterial wird

Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation

Science.gov (United States)

Shiraiwa, Manabu; Yee, Lindsay D.; Schilling, Katherine A.; Loza, Christine L.; Craven, Jill S.; Zuend, Andreas; Ziemann, Paul J.; Seinfeld, John H.

2013-01-01

Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process. PMID:23818634

Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation.

Science.gov (United States)

Shiraiwa, Manabu; Yee, Lindsay D; Schilling, Katherine A; Loza, Christine L; Craven, Jill S; Zuend, Andreas; Ziemann, Paul J; Seinfeld, John H

2013-07-16

Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process.

Particle size distribution of aerosols sprayed from household hand-pump sprays containing fluorine-based and silicone-based compounds.

Science.gov (United States)

Kawakami, Tsuyoshi; Isama, Kazuo; Ikarashi, Yoshiaki

2015-01-01

Japan has published safety guideline on waterproof aerosol sprays. Furthermore, the Aerosol Industry Association of Japan has adopted voluntary regulations on waterproof aerosol sprays. Aerosol particles of diameter less than 10 µm are considered as "fine particles". In order to avoid acute lung injury, this size fraction should account for less than 0.6% of the sprayed aerosol particles. In contrast, the particle size distribution of aerosols released by hand-pump sprays containing fluorine-based or silicone-based compounds have not been investigated in Japan. Thus, the present study investigated the aerosol particle size distribution of 16 household hand-pump sprays. In 4 samples, the ratio of fine particles in aerosols exceeded 0.6%. This study confirmed that several hand-pump sprays available in the Japanese market can spray fine particles. Since the hand-pump sprays use water as a solvent and their ingredients may be more hydrophilic than those of aerosol sprays, the concepts related to the safety of aerosol-sprays do not apply to the hand pump sprays. Therefore, it may be required for the hand-pump spray to develop a suitable method for evaluating the toxicity and to establish the safety guideline.

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.

Reduced anthropogenic aerosol radiative forcing caused by biogenic new particle formation

Science.gov (United States)

Gordon, Hamish; Sengupta, Kamalika; Rap, Alexandru; Duplissy, Jonathan; Frege, Carla; Williamson, Christina; Heinritzi, Martin; Simon, Mario; Yan, Chao; Almeida, João; Tröstl, Jasmin; Nieminen, Tuomo; Ortega, Ismael K.; Wagner, Robert; Dunne, Eimear M.; Adamov, Alexey; Amorim, Antonio; Bernhammer, Anne-Kathrin; Bianchi, Federico; Breitenlechner, Martin; Brilke, Sophia; Chen, Xuemeng; Craven, Jill S.; Dias, Antonio; Ehrhart, Sebastian; Fischer, Lukas; Flagan, Richard C.; Franchin, Alessandro; Fuchs, Claudia; Guida, Roberto; Hakala, Jani; Hoyle, Christopher R.; Jokinen, Tuija; Junninen, Heikki; Kangasluoma, Juha; Kim, Jaeseok; Kirkby, Jasper; Krapf, Manuel; Kürten, Andreas; Laaksonen, Ari; Lehtipalo, Katrianne; Makhmutov, Vladimir; Mathot, Serge; Molteni, Ugo; Monks, Sarah A.; Onnela, Antti; Peräkylä, Otso; Piel, Felix; Petäjä, Tuukka; Praplan, Arnaud P.; Pringle, Kirsty J.; Richards, Nigel A. D.; Rissanen, Matti P.; Rondo, Linda; Sarnela, Nina; Schobesberger, Siegfried; Scott, Catherine E.; Seinfeld, John H.; Sharma, Sangeeta; Sipilä, Mikko; Steiner, Gerhard; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Virtanen, Annele; Vogel, Alexander Lucas; Wagner, Andrea C.; Wagner, Paul E.; Weingartner, Ernest; Wimmer, Daniela; Winkler, Paul M.; Ye, Penglin; Zhang, Xuan; Hansel, Armin; Dommen, Josef; Donahue, Neil M.; Worsnop, Douglas R.; Baltensperger, Urs; Kulmala, Markku; Curtius, Joachim; Carslaw, Kenneth S.

2016-10-01

The magnitude of aerosol radiative forcing caused by anthropogenic emissions depends on the baseline state of the atmosphere under pristine preindustrial conditions. Measurements show that particle formation in atmospheric conditions can occur solely from biogenic vapors. Here, we evaluate the potential effect of this source of particles on preindustrial cloud condensation nuclei (CCN) concentrations and aerosol-cloud radiative forcing over the industrial period. Model simulations show that the pure biogenic particle formation mechanism has a much larger relative effect on CCN concentrations in the preindustrial atmosphere than in the present atmosphere because of the lower aerosol concentrations. Consequently, preindustrial cloud albedo is increased more than under present day conditions, and therefore the cooling forcing of anthropogenic aerosols is reduced. The mechanism increases CCN concentrations by 20-100% over a large fraction of the preindustrial lower atmosphere, and the magnitude of annual global mean radiative forcing caused by changes of cloud albedo since 1750 is reduced by 0.22 W m-2 (27%) to -0.60 W m-2. Model uncertainties, relatively slow formation rates, and limited available ambient measurements make it difficult to establish the significance of a mechanism that has its dominant effect under preindustrial conditions. Our simulations predict more particle formation in the Amazon than is observed. However, the first observation of pure organic nucleation has now been reported for the free troposphere. Given the potentially significant effect on anthropogenic forcing, effort should be made to better understand such naturally driven aerosol processes.

Reduced anthropogenic aerosol radiative forcing caused by biogenic new particle formation.

Science.gov (United States)

Gordon, Hamish; Sengupta, Kamalika; Rap, Alexandru; Duplissy, Jonathan; Frege, Carla; Williamson, Christina; Heinritzi, Martin; Simon, Mario; Yan, Chao; Almeida, João; Tröstl, Jasmin; Nieminen, Tuomo; Ortega, Ismael K; Wagner, Robert; Dunne, Eimear M; Adamov, Alexey; Amorim, Antonio; Bernhammer, Anne-Kathrin; Bianchi, Federico; Breitenlechner, Martin; Brilke, Sophia; Chen, Xuemeng; Craven, Jill S; Dias, Antonio; Ehrhart, Sebastian; Fischer, Lukas; Flagan, Richard C; Franchin, Alessandro; Fuchs, Claudia; Guida, Roberto; Hakala, Jani; Hoyle, Christopher R; Jokinen, Tuija; Junninen, Heikki; Kangasluoma, Juha; Kim, Jaeseok; Kirkby, Jasper; Krapf, Manuel; Kürten, Andreas; Laaksonen, Ari; Lehtipalo, Katrianne; Makhmutov, Vladimir; Mathot, Serge; Molteni, Ugo; Monks, Sarah A; Onnela, Antti; Peräkylä, Otso; Piel, Felix; Petäjä, Tuukka; Praplan, Arnaud P; Pringle, Kirsty J; Richards, Nigel A D; Rissanen, Matti P; Rondo, Linda; Sarnela, Nina; Schobesberger, Siegfried; Scott, Catherine E; Seinfeld, John H; Sharma, Sangeeta; Sipilä, Mikko; Steiner, Gerhard; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Virtanen, Annele; Vogel, Alexander Lucas; Wagner, Andrea C; Wagner, Paul E; Weingartner, Ernest; Wimmer, Daniela; Winkler, Paul M; Ye, Penglin; Zhang, Xuan; Hansel, Armin; Dommen, Josef; Donahue, Neil M; Worsnop, Douglas R; Baltensperger, Urs; Kulmala, Markku; Curtius, Joachim; Carslaw, Kenneth S

2016-10-25

The magnitude of aerosol radiative forcing caused by anthropogenic emissions depends on the baseline state of the atmosphere under pristine preindustrial conditions. Measurements show that particle formation in atmospheric conditions can occur solely from biogenic vapors. Here, we evaluate the potential effect of this source of particles on preindustrial cloud condensation nuclei (CCN) concentrations and aerosol-cloud radiative forcing over the industrial period. Model simulations show that the pure biogenic particle formation mechanism has a much larger relative effect on CCN concentrations in the preindustrial atmosphere than in the present atmosphere because of the lower aerosol concentrations. Consequently, preindustrial cloud albedo is increased more than under present day conditions, and therefore the cooling forcing of anthropogenic aerosols is reduced. The mechanism increases CCN concentrations by 20-100% over a large fraction of the preindustrial lower atmosphere, and the magnitude of annual global mean radiative forcing caused by changes of cloud albedo since 1750 is reduced by [Formula: see text] (27%) to [Formula: see text] Model uncertainties, relatively slow formation rates, and limited available ambient measurements make it difficult to establish the significance of a mechanism that has its dominant effect under preindustrial conditions. Our simulations predict more particle formation in the Amazon than is observed. However, the first observation of pure organic nucleation has now been reported for the free troposphere. Given the potentially significant effect on anthropogenic forcing, effort should be made to better understand such naturally driven aerosol processes.

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.

The physico-chemical evolution of atmospheric aerosols and the gas-particle partitioning of inorganic aerosol during KORUS-AQ

Science.gov (United States)

Lee, T.; Park, T.; Lee, J. B.; Lim, Y. J.; Ahn, J.; Park, J. S.; Soo, C. J.; Desyaterik, Y.; Collett, J. L., Jr.

2017-12-01

Aerosols influence climate change directly by scattering and absorption and indirectly by acting as cloud condensation nuclei and some of the effects of aerosols are reduction in visibility, deterioration of human health, and deposition of pollutants to ecosystems. Urban area is large source of aerosols and aerosol precursors. Aerosol sources are both local and from long-range transport. Long-range transport processed aerosol are often dominant sources of aerosol pollution in Korea. To improve our knowledge of aerosol chemistry, Korea and U.S-Air Quality (KORUS-AQ) of Aircraft-based aerosol measurement took place in and around Seoul, Korea during May and June 2016. KORUS-AQ campaigns were conducted to study the chemical characterization and processes of pollutants in the Seoul Metropolitan area to regional scales of Korean peninsula. Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed on aircraft platforms on-board DC-8 (NASA) aircraft. We characterized aerosol chemical properties and mass concentrations of sulfate, nitrate, ammonium and organics in polluted air plumes and investigate the spatial and vertical distribution of the species. The results of studies show that organics is predominant in Aerosol and a significant fraction of the organics is oxygenated organic aerosol (OOA) at the high altitude. Both Nitrate and sulfate can partition between the gas and particle phases. The ratios for HNO3/(N(V) (=gaseous HNO3 + particulate Nitrate) and SO2/(SO2+Sulfate) were found to exhibit quite different distributions between the particles and gas phase for the locations during KORUS-AQ campaign, representing potential for formation of additional particulate nitrate and sulfate. The results of those studies can provide highly resolved temporal and spatial air pollutant, which are valuable for air quality model input parameters for aerosol behaviour.

Aerosol Particle Interfacial Thermodynamics and Phase Partitioning Measurements Using Biphasic Microfluidics

Science.gov (United States)

Dutcher, Cari; Metcalf, Andrew

2015-03-01

Secondary organic aerosol particles are nearly ubiquitous in the atmosphere and yet there remain large uncertainties in their formation processes and ambient properties. These particles are complex microenvironments, which can contain multiple interfaces due to internal aqueous-organic phase partitioning and to the external liquid-vapor surface. Interfacial properties affect the ambient aerosol morphology, or internal structure of the particle, which in turn can affect the way a particle interacts with an environment of condensable clusters and organic vapors. To improve our ability to accurately predict ambient aerosol morphology, we must improve our knowledge of aerosol interfaces and their interactions with the ambient environment. Unfortunately, many techniques employed to measure interfacial properties do so in bulk solutions or in the presence of a ternary (e.g. solid) phase. In this talk, a novel method using biphasic microscale flows will be introduced for generating, trapping, and perturbing complex interfaces at atmospherically relevant conditions. These microfluidic experiments utilize high-speed imaging to monitor interfacial phenomena at the microscale and are performed with phase contrast and fluorescence microscopy on a temperature-controlled inverted microscope stage. From these experiments, interfacial thermodynamic properties such as surface or interfacial tension, rheological properties such as interfacial moduli, and kinetic properties such as mass transfer coefficients can be measured or inferred.

Decomposition of Atmospheric Aerosol Phase Function by Particle Size and Morphology via Single Particle Scattering Measurements

Science.gov (United States)

Aptowicz, K. B.; Pan, Y.; Martin, S.; Fernandez, E.; Chang, R.; Pinnick, R. G.

2013-12-01

We report upon an experimental approach that provides insight into how particle size and shape affect the scattering phase function of atmospheric aerosol particles. Central to our approach is the design of an apparatus that measures the forward and backward scattering hemispheres (scattering patterns) of individual atmospheric aerosol particles in the coarse mode range. The size and shape of each particle is discerned from the corresponding scattering pattern. In particular, autocorrelation analysis is used to differentiate between spherical and non-spherical particles, the calculated asphericity factor is used to characterize the morphology of non-spherical particles, and the integrated irradiance is used for particle sizing. We found the fraction of spherical particles decays exponentially with particle size, decreasing from 11% for particles on the order of 1 micrometer to less than 1% for particles over 5 micrometer. The average phase functions of subpopulations of particles, grouped by size and morphology, are determined by averaging their corresponding scattering patterns. The phase functions of spherical and non-spherical atmospheric particles are shown to diverge with increasing size. In addition, the phase function of non-spherical particles is found to vary little as a function of the asphericity factor.

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

Science.gov (United States)

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

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.

Stratospheric particles: Synchrotron x-ray fluorescence determination of trace element contents

International Nuclear Information System (INIS)

Sutton, S.R.; Flynn, G.J.

1987-01-01

The first trace element analyses on stratospheric particles using synchrotron x-ray fluorescence (SXRF) are reported. Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, Se and Br were detected. Concentrations for chondritic particle U2022G1 are within a factor of 1.7 of CI for all elements detected with the exception of Br which is 37 times CI. Chondritic particle W7029*A27 is also near CI for Cr, Mn, Fe, Ni, Cu, Zn and Ge but enriched in Ga, Se, and Br by factors of 5.8, 3.5 and 8.4, respectively. The third particle of the cosmic dust class also showed high Br enriched relative to CI by a factor of 28. Br was also detected at a high level in an aluminum-rich particle classified as probable artificial terrestrial contamination but exhibiting a chondritic Fe/Ni ratio. Br was not detected in a fifth particle also classified terrestrial and exhibiting a crustal Fe/Ni ratio. If the high Br has a pre-terrestrial origin, the ubiquity of the effect suggests that a large fraction of the chondritic interplanetary dust particles derive from a parent body (bodies) not sampled in the meteorite collection. 26 refs., 3 figs., 3 tabs

Wintertime hygroscopicity and volatility of ambient urban aerosol particles

Directory of Open Access Journals (Sweden)

J. Enroth

2018-04-01

Full Text Available Hygroscopic and volatile properties of atmospheric aerosol particles with dry diameters of (20, 50, 75, 110 and 145 nm were determined in situ by using a volatility–hygroscopicity tandem differential mobility analyser (VH-TDMA system with a relative humidity of 90 % and denuding temperature of 270 °C in central Budapest during 2 months in winter 2014–2015. The probability density function of the hygroscopic growth factor (HGF showed a distinct bimodal distribution. One of the modes was characterised by an overall mean HGF of approximately 1.07 (this corresponds to a hygroscopicity parameter κ of 0.033 independently of the particle size and was assigned to nearly hydrophobic (NH particles. Its mean particle number fraction was large, and it decreased monotonically from 69 to 41 % with particle diameter. The other mode showed a mean HGF increasing slightly from 1.31 to 1.38 (κ values from 0.186 to 0.196 with particle diameter, and it was attributed to less hygroscopic (LH particles. The mode with more hygroscopic particles was not identified. The probability density function of the volatility GF (VGF also exhibited a distinct bimodal distribution with an overall mean VGF of approximately 0.96 independently of the particle size, and with another mean VGF increasing from 0.49 to 0.55 with particle diameter. The two modes were associated with less volatile (LV and volatile (V particles. The mean particle number fraction for the LV mode decreased from 34 to 21 % with particle diameter. The bimodal distributions indicated that the urban atmospheric aerosol contained an external mixture of particles with a diverse chemical composition. Particles corresponding to the NH and LV modes were assigned mainly to freshly emitted combustion particles, more specifically to vehicle emissions consisting of large mass fractions of soot likely coated with or containing some water-insoluble organic compounds such as non

The single scattering properties of the aerosol particles as aggregated spheres

International Nuclear Information System (INIS)

Wu, Y.; Gu, X.; Cheng, T.; Xie, D.; Yu, T.; Chen, H.; Guo, J.

2012-01-01

The light scattering and absorption properties of anthropogenic aerosol particles such as soot aggregates are complicated in the temporal and spatial distribution, which introduce uncertainty of radiative forcing on global climate change. In order to study the single scattering properties of anthorpogenic aerosol particles, the structures of these aerosols such as soot paticles and soot-containing mixtures with the sulfate or organic matter, are simulated using the parallel diffusion limited aggregation algorithm (DLA) based on the transmission electron microscope images (TEM). Then, the single scattering properties of randomly oriented aerosols, such as scattering matrix, single scattering albedo (SSA), and asymmetry parameter (AP), are computed using the superposition T-matrix method. The comparisons of the single scattering properties of these specific types of clusters with different morphological and chemical factors such as fractal parameters, aspect ratio, monomer radius, mixture mode and refractive index, indicate that these different impact factors can respectively generate the significant influences on the single scattering properties of these aerosols. The results show that aspect ratio of circumscribed shape has relatively small effect on single scattering properties, for both differences of SSA and AP are less than 0.1. However, mixture modes of soot clusters with larger sulfate particles have remarkably important effects on the scattering and absorption properties of aggregated spheres, and SSA of those soot-containing mixtures are increased in proportion to the ratio of larger weakly absorbing attachments. Therefore, these complex aerosols come from man made pollution cannot be neglected in the aerosol retrievals. The study of the single scattering properties on these kinds of aggregated spheres is important and helpful in remote sensing observations and atmospheric radiation balance computations.

Variation in penetration of submicrometric particles through electrostatic filtering facepieces during exposure to paraffin oil aerosol.

Science.gov (United States)

Plebani, Carmela; Listrani, Stefano; Tranfo, Giovanna; Tombolini, Francesca

2012-01-01

Several studies show the increase of penetration through electrostatic filters during exposure to an aerosol flow, because of particle deposition on filter fibers. We studied the effect of increasing loads of paraffin oil aerosol on the penetration of selected particle sizes through an electrostatic filtering facepiece. FFP2 facepieces were exposed for 8 hr to a flow rate of 95.0 ± 0.5 L/min of polydisperse paraffin aerosol at 20.0 ± 0.5 mg/m(3). The penetration of bis(2-ethylhexyl)sebacate (DEHS) monodisperse neutralized aerosols, with selected particle size in the 0.03-0.40 μm range, was measured immediately prior to the start of the paraffin aerosol loading and at 1, 4, and 8 hr after the start of paraffin aerosol loading. Penetration through isopropanol-treated facepieces not oil paraffin loaded was also measured to evaluate facepiece behavior when electrostatic capture mechanisms are practically absent. During exposure to paraffin aerosol, DEHS penetration gradually increased for all aerosol sizes, and the most penetrating particle size (0.05 μm at the beginning of exposure) shifted slightly to larger diameters. After the isopropanol treatment, the higher penetration value was 0.30 μm. In addition to an increased penetration during paraffin loading at a given particle size, the relative degree of increase was greater as the particle size increased. Penetration value measured after 8 hr for 0.03-μm particles was on average 1.6 times the initial value, whereas it was about 8 times for 0.40-μm particles. This behavior, as well evidenced in the measurements of isopropanol-treated facepieces, can be attributed to the increasing action in particle capture of the electrostatic forces (Coulomb and polarization), which depend strictly on the diameter and electrical charge of neutralized aerosol particles. With reference to electrostatic filtering facepieces as personal protective equipment, results suggest the importance of complying with the manufacturer

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.

Penetration of Combustion Aerosol Particles Through Filters of NIOSH-Certified Filtering Facepiece Respirators (FFRs).

Science.gov (United States)

Gao, Shuang; Kim, Jinyong; Yermakov, Michael; Elmashae, Yousef; He, Xinjian; Reponen, Tiina; Grinshpun, Sergey A

2015-01-01

Filtering facepiece respirators (FFRs) are commonly worn by first responders, first receivers, and other exposed groups to protect against exposure to airborne particles, including those originated by combustion. Most of these FFRs are NIOSH-certified (e.g., N95-type) based on the performance testing of their filters against charge-equilibrated aerosol challenges, e.g., NaCl. However, it has not been examined if the filtration data obtained with the NaCl-challenged FFR filters adequately represent the protection against real aerosol hazards such as combustion particles. A filter sample of N95 FFR mounted on a specially designed holder was challenged with NaCl particles and three combustion aerosols generated in a test chamber by burning wood, paper, and plastic. The concentrations upstream (Cup) and downstream (Cdown) of the filter were measured with a TSI P-Trak condensation particle counter and a Grimm Nanocheck particle spectrometer. Penetration was determined as (Cdown/Cup) ×100%. Four test conditions were chosen to represent inhalation flows of 15, 30, 55, and 85 L/min. Results showed that the penetration values of combustion particles were significantly higher than those of the "model" NaCl particles (p combustion particles. Aerosol type, inhalation flow rate and particle size were significant (p combustion particles through R95 and P95 FFR filters (were tested in addition to N95) were not significantly higher than that obtained with NaCl particles. The findings were attributed to several effects, including the degradation of an N95 filter due to hydrophobic organic components generated into the air by combustion. Their interaction with fibers is anticipated to be similar to those involving "oily" particles. The findings of this study suggest that the efficiency of N95 respirator filters obtained with the NaCl aerosol challenge may not accurately predict (and rather overestimate) the filter efficiency against combustion particles.

Quantitative determination of carbonaceous particle mixing state in Paris using single particle mass spectrometer and aerosol mass spectrometer measurements

Science.gov (United States)

Healy, R. M.; Sciare, J.; Poulain, L.; Crippa, M.; Wiedensohler, A.; Prévôt, A. S. H.; Baltensperger, U.; Sarda-Estève, R.; McGuire, M. L.; Jeong, C.-H.; McGillicuddy, E.; O'Connor, I. P.; Sodeau, J. R.; Evans, G. J.; Wenger, J. C.

2013-04-01

Single particle mixing state information can be a powerful tool for assessing the relative impact of local and regional sources of ambient particulate matter in urban environments. However, quantitative mixing state data are challenging to obtain using single particle mass spectrometers. In this study, the quantitative chemical composition of carbonaceous single particles has been estimated using an aerosol time-of-flight mass spectrometer (ATOFMS) as part of the MEGAPOLI 2010 winter campaign in Paris, France. Relative peak areas of marker ions for elemental carbon (EC), organic aerosol (OA), ammonium, nitrate, sulphate and potassium were compared with concurrent measurements from an Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), a thermal/optical OCEC analyser and a particle into liquid sampler coupled with ion chromatography (PILS-IC). ATOFMS-derived mass concentrations reproduced the variability of these species well (R2 = 0.67-0.78), and ten discrete mixing states for carbonaceous particles were identified and quantified. Potassium content was used to identify particles associated with biomass combustion. The chemical mixing state of HR-ToF-AMS organic aerosol factors, resolved using positive matrix factorization, was also investigated through comparison with the ATOFMS dataset. The results indicate that hydrocarbon-like OA (HOA) detected in Paris is associated with two EC-rich mixing states which differ in their relative sulphate content, while fresh biomass burning OA (BBOA) is associated with two mixing states which differ significantly in their OA/EC ratios. Aged biomass burning OA (OOA2-BBOA) was found to be significantly internally mixed with nitrate, while secondary, oxidized OA (OOA) was associated with five particle mixing states, each exhibiting different relative secondary inorganic ion content. Externally mixed secondary organic aerosol was not observed. These findings demonstrate the heterogeneity of primary and

Individual aerosol particles in and below clouds along a Mt. Fuji slope: Modification of sea-salt-containing particles by in-cloud processing

Science.gov (United States)

Ueda, S.; Hirose, Y.; Miura, K.; Okochi, H.

2014-02-01

Sizes and compositions of atmospheric aerosol particles can be altered by in-cloud processing by absorption/adsorption of gaseous and particulate materials and drying of aerosol particles that were formerly activated as cloud condensation nuclei. To elucidate differences of aerosol particles before and after in-cloud processing, aerosols were observed along a slope of Mt. Fuji, Japan (3776 m a.s.l.) during the summer in 2011 and 2012 using a portable laser particle counter (LPC) and an aerosol sampler. Aerosol samples for analyses of elemental compositions were obtained using a cascade impactor at top-of-cloud, in-cloud, and below-cloud altitudes. To investigate composition changes via in-cloud processing, individual particles (0.5-2 μm diameter) of samples from five cases (days) collected at different altitudes under similar backward air mass trajectory conditions were analyzed using a transmission electron microscope (TEM) equipped with an energy dispersive X-ray analyzer. For most cases (four cases), most particles at all altitudes mainly comprised sea salts: mainly Na with some S and/or Cl. Of those, in two cases, sea-salt-containing particles with Cl were found in below-cloud samples, although sea-salt-containing particles in top-of-cloud samples did not contain Cl. This result suggests that Cl in the sea salt was displaced by other cloud components. In the other two cases, sea-salt-containing particles on samples at all altitudes were without Cl. However, molar ratios of S to Na (S/Na) of the sea-salt-containing particles of top-of-cloud samples were higher than those of below-cloud samples, suggesting that sulfuric acid or sulfate was added to sea-salt-containing particles after complete displacement of Cl by absorption of SO2 or coagulation with sulfate. The additional volume of sulfuric acid in clouds for the two cases was estimated using the observed S/Na values of sea-salt-containing particles. The estimation revealed that size changes by in

Physical properties of the arctic summer aerosol particles in relation ...

Indian Academy of Sciences (India)

The sea-salt particles of marine origin generated within the Arctic circle are identified as the main source of the Arctic summer aerosols. ... concentration starts decreasing within a few minutes from the start of these events but requires a few hours to restore to the normal background aerosol level after the end of event.

Detection of /sup 4/He in stratospheric particles gives evidence of extraterrestrial origin

Energy Technology Data Exchange (ETDEWEB)

Rajan, R S [Carnegie Institution of Washington, D.C. (USA). Dept. of Terrestrial Magnetism; Brownlee, D E; Tomandl, D; Hodge, P W; Farrar, H; Britten, R A

1977-05-12

The detection of large concentrations of /sup 4/He in some ..mu..m size stratospheric particles collected during the past 2 years is here reported. The final /sup 4/He concentrations ranged from 0.002 to 0.25 cc/gm. Such high concentrations confirm that the particles were extraterrestrial and that some of them were exposed to solar wind for at least 10 to 100 years; also, since solar wind ions are implanted only to depths of approximately 500 A, the measurements also indicate that the particles existed as small particles in space and were not produced in the atmosphere by fragmentation of larger meteoroids. The possibility that the observed He could have been the product of decaying U appears remote. Since micrometeorites probably have cometary origin, they are potentially a valuable source of primitive Solar System matter.

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.

Aerosol nucleation induced by a high energy particle beam

DEFF Research Database (Denmark)

Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, Ulrik I.

2011-01-01

We have studied sulfuric acid aerosol nucleation in an atmospheric pressure reaction chamber using a 580 MeV electron beam to ionize the volume of the reaction chamber. We find a clear contribution from ion-induced nucleation and consider this to be the first unambiguous observation of the ion......-effect on aerosol nucleation using a particle beam under conditions that resemble the Earth's atmosphere. By comparison with ionization using a gamma source we further show that the nature of the ionizing particles is not important for the ion-induced component of the nucleation. This implies that inexpensive...... ionization sources - as opposed to expensive accelerator beams - can be used for investigations of ion-induced nucleation....

Seasonal variations and vertical features of aerosol particles in the Antarctic troposphere

Directory of Open Access Journals (Sweden)

Keiichiro Hara

2010-12-01

Full Text Available Tethered balloon-borne aerosol measurements were carried out at Syowa Station, Antarctica during the 46th Japanese Antarctic Research Expedition. CN concentration had a maximum in the summer, whereas the number concentrations of fine particles (D_p>0.3 μm and coarse particles (D_p>2.0 μm increased during the winter-spring. The range of CN concentration was 30-2200 cm^ near the surface (surface-500 m and 7-7250 cm^ in the lower free troposphere (>1500 m. During the austral summer, higher CN concentration was often observed in the lower free troposphere. Frequent appearance of higher CN concentration in the free troposphere relative to the surface measurements strongly suggests that new particle formation in the Antarctic regions occurs in the lower free troposphere. Single particle analysis indicated that most of the aerosol particles during the winter were composed of Mg-enriched sea-salt particles originated from sea-salt fractionation on the sea-ice and their modified particles by NO_3^ and SO_4^. This suggests that sea-salt fractionation on sea-ice and modification of sea-salt particles were affected greatly by aerosol hygroscopicity during the winter. Antarctic haze layer was observed not only in the boundary layer but also in the lower free troposphere.

Single particle characterization, source apportionment, and aging effects of ambient aerosols in Southern California

Science.gov (United States)

Shields, Laura Grace

Composed of a mixture of chemical species and phases and existing in a variety of shapes and sizes, atmospheric aerosols are complex and can have serious influence on human health, the environment, and climate. In order to better understand the impact of aerosols on local to global scales, detailed measurements on the physical and chemical properties of ambient particles are essential. In addition, knowing the origin or the source of the aerosols is important for policymakers to implement targeted regulations and effective control strategies to reduce air pollution in their region. One of the most ground breaking techniques in aerosol instrumentation is single particle mass spectrometry (SPMS), which can provide online chemical composition and size information on the individual particle level. The primary focus of this work is to further improve the ability of one specific SPMS technique, aerosol time-of-flight mass spectrometry (ATOFMS), for the use of identifying the specific origin of ambient aerosols, which is known as source apportionment. The ATOFMS source apportionment method utilizes a library of distinct source mass spectral signatures to match the chemical information of the single ambient particles. The unique signatures are obtained in controlled source characterization studies, such as with the exhaust emissions of heavy duty diesel vehicles (HDDV) operating on a dynamometer. The apportionment of ambient aerosols is complicated by the chemical and physical processes an individual particle can undergo as it spends time in the atmosphere, which is referred to as "aging" of the aerosol. Therefore, the performance of the source signature library technique was investigated on the ambient dataset of the highly aged environment of Riverside, California. Additionally, two specific subsets of the Riverside dataset (ultrafine particles and particles containing trace metals), which are known to cause adverse health effects, were probed in greater detail. Finally

Representation of aerosol particles and associated transport pathways in regional climate modelling in Africa

CSIR Research Space (South Africa)

Garland, Rebecca M

2016-11-01

Full Text Available Aerosol particles can have large impacts on air quality and on the climate system. Regional climate models for Africa have not been well-tested and validated for their representation and simulation of aerosol particles. This study aimed to validate...

Development and experimental evaluation of an optical sensor for aerosol particle characterization

Energy Technology Data Exchange (ETDEWEB)

Somesfalean, G.

1998-03-01

A sensor for individual aerosol particle characterization, based on a single-mode semiconductor laser coupled to an external cavity is presented. The light emitting semiconductor laser acts as a sensitive optical detector itself, and the whole system has the advantage of using conventional optical components and providing a compact set-up. Aerosol particles moving through the sensing volume, which is located in the external cavity of a semiconductor laser, scatter and absorb light. Thereby they act as small disturbances on the electromagnetic field inside the dynamic multi-cavity laser system. From the temporal variation of the output light intensity, information about the number, velocity, size, and refractive index of the aerosol particles can be derived. The diffracted light in the near-forward scattering direction is collected and Fourier-transformed by a lens, and subsequently imaged on a CCD camera. The recorded Fraunhofer diffraction pattern provides information about the projected area of the scattering particle, and can thus be used to determine the size and the shape of aerosol particles. The sensor has been tested on fibers which are of interest in the field of working environment monitoring. The recorded output intensity variation has been analysed, and the relationship between the shape and the size of each fibre, and the resulting scattering profiles has been investigated. A simple one-dimensional model for the optical feedback variation due to the light-particle interaction in the external cavity is also discussed 34 refs, 26 figs, 6 tabs

A novel tandem differential mobility analyzer with organic vapor treatment of aerosol particles

Directory of Open Access Journals (Sweden)

J. Joutsensaari

2001-01-01

Full Text Available A novel method to characterize the organic composition of aerosol particles has been developed. The method is based on organic vapor interaction with aerosol particles and it has been named an Organic Tandem Differential Mobility Analyzer (OTDMA. The OTDMA method has been tested for inorganic (sodium chloride and ammonium sulfate and organic (citric acid and adipic acid particles. Growth curves of the particles have been measured in ethanol vapor and as a comparison in water vapor as a function of saturation ratio. Measurements in water vapor show that sodium chloride and ammonium sulfate as well as citric acid particles grow at water saturation ratios (S of 0.8 and above, whereas adipic acid particles do not grow at S S = 0.75 and S = 0.79, respectively. Citric acid particles grow monotonously with increasing saturation ratios already at low saturation ratios and no clear deliquescence point is found. For sodium chloride and ammonium sulfate particles, no growth can be seen in ethanol vapor at saturation ratios below 0.93. In contrast, for adipic acid particles, the deliquescence takes place at around S = 0.95 in the ethanol vapor. The recrystallization of adipic acid takes place at S The results show that the working principles of the OTDMA are operational for single-component aerosols. Furthermore, the results indicate that the OTDMA method may prove useful in determining whether aerosol particles contain organic substances, especially if the OTDMA is operated in parallel with a hygroscopicity TDMA, as the growth of many substances is different in ethanol and water vapors.

Chemical composition of individual aerosol particles from working areas in a nickel refinery.

Science.gov (United States)

Höflich, B L; Wentzel, M; Ortner, H M; Weinbruch, S; Skogstad, A; Hetland, S; Thomassen, Y; Chaschin, V P; Nieboer, E

2000-06-01

Individual aerosol particles (n = 1170) collected at work stations in a nickel refinery were analyzed by wavelength-dispersive electron-probe microanalysis. By placing arbitrary restrictions on the contents of sulfur and silicon, the particles could be divided into four main groups. Scanning electron images indicated that most of the particles examined were relatively small (refinery intermediates. The implications of the findings for aerosol speciation measurements, toxicological studies and interpretation of adverse health effects are explored.

How stratospheric are deep stratospheric intrusions? LUAMI 2008

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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

The thermal history of interplanetary dust particles collected in the Earth's stratosphere

Science.gov (United States)

Nier, A. O.; Schlutter, D. J.

1993-01-01

Fragments of 24 individual interplanetary dust particles (IDPs) collected in the Earth's stratosphere were obtained from NASA's Johnson Space Center collection and subjected to pulse-heating sequences to extract He and Ne and to learn about the thermal history of the particles. A motivation for the investigation was to see if the procedure would help distinguish between IDPs of asteroidal and cometary origin. The use of a sequence of short-duration heat pulses to perform the extractions is an improvement over the employment of a step-heating sequence, as was used in a previous investigation. The particles studied were fragments of larger parent IDPs, other fragments of which, in coordinated experiments, are undergoing studies of elemental and mineralogical composition in other laboratories. While the present investigation will provide useful temperature history data for the particles, the relatively large size of the parent IDPs (approximately 40 micrometers in diameter) resulted in high entry deceleration temperatures. This limited the usefulness of the study for distinguishing between particles of asteroidal and cometary origin.

Determination of the particle size distribution of aerosols by means of a diffusion battery

International Nuclear Information System (INIS)

Maigne, J.P.

1978-09-01

The different methods allowing to determine the particle size distribution of aerosols by means of diffusion batteries are described. To that purpose, a new method for the processing of experimental data (percentages of particles trapped by the battery vs flow rate) was developed on the basis of calculation principles which are described and assessed. This method was first tested by numerical simulation from a priori particle size distributions and then verified experimentally using a fine uranine aerosol whose particle size distribution as determined by our method was compared with the distribution previously obtained by electron microscopy. The method can be applied to the determination of particle size distribution spectra of fine aerosols produced by 'radiolysis' of atmospheric gaseous impurities. Two other applications concern the detection threshold of the condensation nuclei counter and the 'critical' radii of 'radiolysis' particles [fr

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

Directory of Open Access Journals (Sweden)

Slemr F.

2013-04-01

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

Elemental composition of aerosol particles from two atmospheric monitoring stations in the Amazon Basin

International Nuclear Information System (INIS)

Artaxo, P.; Gerab, F.; Rabello, M.L.C.

1993-01-01

One key region for the study of processes that are changing the composition of the global atmosphere is the Amazon Basin tropical rain forest. The high rate of deforestation and biomass burning is emitting large amounts of gases and fine-mode aerosol particles to the global atmosphere. Two background monitoring stations are operating continuously measuring aerosol composition, at Cuiaba, and Serra do Navio. Fine- and coarse-mode aerosol particles are being collected using stacked filter units. Particle induced X-ray emission (PIXE) was used to measure concentrations of up to 21 elements: Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr, Zr, and Pb. The elemental composition was measured at the new PIXE facility from the University of Sao Paulo, using a dedicated 5SDH tandem Pelletron nuclear accelerator. Absolute principal factor analysis (APFA) has derived absolute elemental source profiles. At the Serra do Navio sampling site a very clean background aerosol is being observed. Biogenic aerosol dominates the fine-mode mass concentration, with the presence of K, P, S, Cl, Zn, Br, and FPM. Three components dominate the aerosol composition: Soil dust particles, the natural biogenic release by the forest, and a marine aerosol component. At the Cuiaba site, during the dry season, a strong component of biomass burning is observed. An aerosol mass concentration up to 120 μg/m 3 was measured. APFA showed three components: Soil dust (Al, Ca, Ti, Mn, Fe), biomass burning (soot, FPM, K, Cl) and natural biogenic particles (K, S, Ca, Mn, Zn). The fine-mode biogenic component of both sites shows remarkable similarities, although the two sampling sites are 3000 km apart. Several essential plant nutrients like P, K, S, Ca, Ni and others are transported in the atmosphere as a result of biomass burning processes. (orig.)

Quantitative determination of carbonaceous particle mixing state in Paris using single-particle mass spectrometer and aerosol mass spectrometer measurements

Directory of Open Access Journals (Sweden)

R. M. Healy

2013-09-01

Full Text Available Single-particle mixing state information can be a powerful tool for assessing the relative impact of local and regional sources of ambient particulate matter in urban environments. However, quantitative mixing state data are challenging to obtain using single-particle mass spectrometers. In this study, the quantitative chemical composition of carbonaceous single particles has been determined using an aerosol time-of-flight mass spectrometer (ATOFMS as part of the MEGAPOLI 2010 winter campaign in Paris, France. Relative peak areas of marker ions for elemental carbon (EC, organic aerosol (OA, ammonium, nitrate, sulfate and potassium were compared with concurrent measurements from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, a thermal–optical OCEC analyser and a particle into liquid sampler coupled with ion chromatography (PILS-IC. ATOFMS-derived estimated mass concentrations reproduced the variability of these species well (R2 = 0.67–0.78, and 10 discrete mixing states for carbonaceous particles were identified and quantified. The chemical mixing state of HR-ToF-AMS organic aerosol factors, resolved using positive matrix factorisation, was also investigated through comparison with the ATOFMS dataset. The results indicate that hydrocarbon-like OA (HOA detected in Paris is associated with two EC-rich mixing states which differ in their relative sulfate content, while fresh biomass burning OA (BBOA is associated with two mixing states which differ significantly in their OA / EC ratios. Aged biomass burning OA (OOA2-BBOA was found to be significantly internally mixed with nitrate, while secondary, oxidised OA (OOA was associated with five particle mixing states, each exhibiting different relative secondary inorganic ion content. Externally mixed secondary organic aerosol was not observed. These findings demonstrate the range of primary and secondary organic aerosol mixing states in Paris. Examination of the

Quantitative determination of carbonaceous particle mixing state in Paris using single-particle mass spectrometer and aerosol mass spectrometer measurements

Science.gov (United States)

Healy, R. M.; Sciare, J.; Poulain, L.; Crippa, M.; Wiedensohler, A.; Prévôt, A. S. H.; Baltensperger, U.; Sarda-Estève, R.; McGuire, M. L.; Jeong, C.-H.; McGillicuddy, E.; O'Connor, I. P.; Sodeau, J. R.; Evans, G. J.; Wenger, J. C.

2013-09-01

Single-particle mixing state information can be a powerful tool for assessing the relative impact of local and regional sources of ambient particulate matter in urban environments. However, quantitative mixing state data are challenging to obtain using single-particle mass spectrometers. In this study, the quantitative chemical composition of carbonaceous single particles has been determined using an aerosol time-of-flight mass spectrometer (ATOFMS) as part of the MEGAPOLI 2010 winter campaign in Paris, France. Relative peak areas of marker ions for elemental carbon (EC), organic aerosol (OA), ammonium, nitrate, sulfate and potassium were compared with concurrent measurements from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), a thermal-optical OCEC analyser and a particle into liquid sampler coupled with ion chromatography (PILS-IC). ATOFMS-derived estimated mass concentrations reproduced the variability of these species well (R2 = 0.67-0.78), and 10 discrete mixing states for carbonaceous particles were identified and quantified. The chemical mixing state of HR-ToF-AMS organic aerosol factors, resolved using positive matrix factorisation, was also investigated through comparison with the ATOFMS dataset. The results indicate that hydrocarbon-like OA (HOA) detected in Paris is associated with two EC-rich mixing states which differ in their relative sulfate content, while fresh biomass burning OA (BBOA) is associated with two mixing states which differ significantly in their OA / EC ratios. Aged biomass burning OA (OOA2-BBOA) was found to be significantly internally mixed with nitrate, while secondary, oxidised OA (OOA) was associated with five particle mixing states, each exhibiting different relative secondary inorganic ion content. Externally mixed secondary organic aerosol was not observed. These findings demonstrate the range of primary and secondary organic aerosol mixing states in Paris. Examination of the temporal

MISR Dark Water aerosol retrievals: operational algorithm sensitivity to particle non-sphericity

Directory of Open Access Journals (Sweden)

O. V. Kalashnikova

2013-08-01

Full Text Available The aim of this study is to theoretically investigate the sensitivity of the Multi-angle Imaging SpectroRadiometer (MISR operational (version 22 Dark Water retrieval algorithm to aerosol non-sphericity over the global oceans under actual observing conditions, accounting for current algorithm assumptions. Non-spherical (dust aerosol models, which were introduced in version 16 of the MISR aerosol product, improved the quality and coverage of retrievals in dusty regions. Due to the sensitivity of the retrieval to the presence of non-spherical aerosols, the MISR aerosol product has been successfully used to track the location and evolution of mineral dust plumes from the Sahara across the Atlantic, for example. However, the MISR global non-spherical aerosol optical depth (AOD fraction product has been found to have several climatological artifacts superimposed on valid detections of mineral dust, including high non-spherical fraction in the Southern Ocean and seasonally variable bands of high non-sphericity. In this paper we introduce a formal approach to examine the ability of the operational MISR Dark Water algorithm to distinguish among various spherical and non-spherical particles as a function of the variable MISR viewing geometry. We demonstrate the following under the criteria currently implemented: (1 Dark Water retrieval sensitivity to particle non-sphericity decreases for AOD below about 0.1 primarily due to an unnecessarily large lower bound imposed on the uncertainty in MISR observations at low light levels, and improves when this lower bound is removed; (2 Dark Water retrievals are able to distinguish between the spherical and non-spherical particles currently used for all MISR viewing geometries when the AOD exceeds 0.1; (3 the sensitivity of the MISR retrievals to aerosol non-sphericity varies in a complex way that depends on the sampling of the scattering phase function and the contribution from multiple scattering; and (4 non

TEM study of soot, organic aerosol, and sea-salt particles collected during CalNex

Science.gov (United States)

Adachi, K.; Buseck, P. R.

2010-12-01

Anthropogenic aerosol particles are emitted in abundance from megacities. Those particles can have important effects on both human health and climate. In this study, aerosol particles having aerodynamic diameters between 50 and 300 nm were collected during the CalNex campaign at the Pasadena ground site from May 15 to June 15, 2010, ~15 km northeast of downtown Los Angeles. The samples were analyzed using transmission electron microscopes (TEMs) to characterize particle shapes and compositions. Most samples are dominated by soot, organic aerosol (OA), sulfate, sea salt, or combinations thereof. Sizes and amounts of OA particles increased during the afternoons, and most soot particles were internally mixed with OA and sulfate in the afternoons. The proportion of soot to other material in individual particles increased and soot particles were more compact during the nights and early mornings. Sea-salt particles were commonly internally mixed with other materials. They have high Na contents with lesser N, Mg, S, K, and Ca and almost no Cl, suggesting that the Cl was replaced by sulfate or nitrate in the atmosphere. There is less OA and more sea salt and sulfate in the CalNex samples than in the samples from Mexico City that were collected during the MILAGRO campaign. Our study indicates that compositions of internally mixed aerosol particles and shapes of soot particles change significantly within a day. These changes probably influence the estimates of their effects on human health and climate.

Chemical ageing and transformation of diffusivity in semi-solid multi-component organic aerosol particles

Science.gov (United States)

Pfrang, C.; Shiraiwa, M.; Pöschl, U.

2011-07-01

Recent experimental evidence underlines the importance of reduced diffusivity in amorphous semi-solid or glassy atmospheric aerosols. This paper investigates the impact of diffusivity on the ageing of multi-component reactive organic particles approximating atmospheric cooking aerosols. We apply and extend the recently developed KM-SUB model in a study of a 12-component mixture containing oleic and palmitoleic acids. We demonstrate that changes in the diffusivity may explain the evolution of chemical loss rates in ageing semi-solid particles, and we resolve surface and bulk processes under transient reaction conditions considering diffusivities altered by oligomerisation. This new model treatment allows prediction of the ageing of mixed organic multi-component aerosols over atmospherically relevant timescales and conditions. We illustrate the impact of changing diffusivity on the chemical half-life of reactive components in semi-solid particles, and we demonstrate how solidification and crust formation at the particle surface can affect the chemical transformation of organic aerosols.

Chemical ageing and transformation of diffusivity in semi-solid multi-component organic aerosol particles

Directory of Open Access Journals (Sweden)

C. Pfrang

2011-07-01

Full Text Available Recent experimental evidence underlines the importance of reduced diffusivity in amorphous semi-solid or glassy atmospheric aerosols. This paper investigates the impact of diffusivity on the ageing of multi-component reactive organic particles approximating atmospheric cooking aerosols. We apply and extend the recently developed KM-SUB model in a study of a 12-component mixture containing oleic and palmitoleic acids. We demonstrate that changes in the diffusivity may explain the evolution of chemical loss rates in ageing semi-solid particles, and we resolve surface and bulk processes under transient reaction conditions considering diffusivities altered by oligomerisation. This new model treatment allows prediction of the ageing of mixed organic multi-component aerosols over atmospherically relevant timescales and conditions. We illustrate the impact of changing diffusivity on the chemical half-life of reactive components in semi-solid particles, and we demonstrate how solidification and crust formation at the particle surface can affect the chemical transformation of organic aerosols.

The generation of diesel exhaust particle aerosols from a bulk source in an aerodynamic size range similar to atmospheric particles

Directory of Open Access Journals (Sweden)

Daniel J Cooney

2008-08-01

Full Text Available Daniel J Cooney1, Anthony J Hickey21Department of Biomedical Engineering; 2School of Pharmacy, University of North Carolina, Chapel Hill, NC, USAAbstract: The influence of diesel exhaust particles (DEP on the lungs and heart is currently a topic of great interest in inhalation toxicology. Epidemiological data and animal studies have implicated airborne particulate matter and DEP in increased morbidity and mortality due to a number of cardiopulmonary diseases including asthma, chronic obstructive pulmonary disorder, and lung cancer. The pathogeneses of these diseases are being studied using animal models and cell culture techniques. Real-time exposures to freshly combusted diesel fuel are complex and require significant infrastructure including engine operations, dilution air, and monitoring and control of gases. A method of generating DEP aerosols from a bulk source in an aerodynamic size range similar to atmospheric DEP would be a desirable and useful alternative. Metered dose inhaler technology was adopted to generate aerosols from suspensions of DEP in the propellant hydrofluoroalkane 134a. Inertial impaction data indicated that the particle size distributions of the generated aerosols were trimodal, with count median aerodynamic diameters less than 100 nm. Scanning electron microscopy of deposited particles showed tightly aggregated particles, as would be expected from an evaporative process. Chemical analysis indicated that there were no major changes in the mass proportion of 2 specific aromatic hydrocarbons (benzo[a]pyrene and benzo[k]fluoranthene in the particles resulting from the aerosolization process.Keywords: diesel exhaust particles, aerosol, inhalation toxicology

Particle integrity, sampling, and application of a DNA-tagged tracer for aerosol transport studies

Energy Technology Data Exchange (ETDEWEB)

Kaeser, Cynthia Jeanne [Michigan State Univ., East Lansing, MI (United States)

2017-07-21

Aerosols are an ever-present part of our daily environment and have extensive effects on both human and environmental health. Particles in the inhalable range (1-10 μm diameter) are of particular concern because their deposition in the lung can lead to a variety of illnesses including allergic reactions, viral or bacterial infections, and cancer. Understanding the transport of inhalable aerosols across both short and long distances is necessary to predict human exposures to aerosols. To assess the transport of hazardous aerosols, surrogate tracer particles are required to measure their transport through occupied spaces. These tracer particles must not only possess similar transport characteristics to those of interest but also be easily distinguished from the background at low levels and survive the environmental conditions of the testing environment. A previously-developed DNA-tagged particle (DNATrax), composed of food-grade sugar and a DNA oligonucleotide as a “barcode” label, shows promise as a new aerosol tracer. Herein, the use of DNATrax material is validated for use in both indoor and outdoor environments. Utilizing passive samplers made of materials commonly found in indoor environments followed by quantitative polymerase chain reaction (qPCR) assay for endpoint particle detection, particles detection was achieved up to 90 m from the aerosolization location and across shorter distances with high spatial resolution. The unique DNA label and PCR assay specificity were leveraged to perform multiple simultaneous experiments. This allowed the assessment of experimental reproducibility, a rare occurrence among aerosol field tests. To transition to outdoor testing, the solid material provides some protection of the DNA label when exposed to ultraviolet (UV) radiation, with 60% of the DNA remaining intact after 60 minutes under a germicidal lamp and the rate of degradation declining with irradiation time. Additionally, exposure of the DNATrax material using

Photochemical aging of aerosol particles in different air masses arriving at Baengnyeong Island, Korea

Science.gov (United States)

Kang, Eunha; Lee, Meehye; Brune, William H.; Lee, Taehyoung; Park, Taehyun; Ahn, Joonyoung; Shang, Xiaona

2018-05-01

Atmospheric aerosol particles are a serious health risk, especially in regions like East Asia. We investigated the photochemical aging of ambient aerosols using a potential aerosol mass (PAM) reactor at Baengnyeong Island in the Yellow Sea during 4-12 August 2011. The size distributions and chemical compositions of aerosol particles were measured alternately every 6 min from the ambient air or through the highly oxidizing environment of a potential aerosol mass (PAM) reactor. Particle size and chemical composition were measured by using the combination of a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Inside the PAM reactor, O3 and OH levels were equivalent to 4.6 days of integrated OH exposure at typical atmospheric conditions. Two types of air masses were distinguished on the basis of the chemical composition and the degree of aging: air transported from China, which was more aged with a higher sulfate concentration and O : C ratio, and the air transported across the Korean Peninsula, which was less aged with more organics than sulfate and a lower O : C ratio. For both episodes, the particulate sulfate mass concentration increased in the 200-400 nm size range when sampled through the PAM reactor. A decrease in organics was responsible for the loss of mass concentration in 100-200 nm particles when sampled through the PAM reactor for the organics-dominated episode. This loss was especially evident for the m/z 43 component, which represents less oxidized organics. The m/z 44 component, which represents further oxidized organics, increased with a shift toward larger sizes for both episodes. It is not possible to quantify the maximum possible organic mass concentration for either episode because only one OH exposure of 4.6 days was used, but it is clear that SO2 was a primary precursor of secondary aerosol in northeast Asia, especially during long-range transport from China. In addition

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.

Deposition of biomass combustion aerosol particles in the human respiratory tract.

Science.gov (United States)

Löndahl, Jakob; Pagels, Joakim; Boman, Christoffer; Swietlicki, Erik; Massling, Andreas; Rissler, Jenny; Blomberg, Anders; Bohgard, Mats; Sandström, Thomas

2008-08-01

Smoke from biomass combustion has been identified as a major environmental risk factor associated with adverse health effects globally. Deposition of the smoke particles in the lungs is a crucial factor for toxicological effects, but has not previously been studied experimentally. We investigated the size-dependent respiratory-tract deposition of aerosol particles from wood combustion in humans. Two combustion conditions were studied in a wood pellet burner: efficient ("complete") combustion and low-temperature (incomplete) combustion simulating "wood smoke." The size-dependent deposition fraction of 15-to 680-nm particles was measured for 10 healthy subjects with a novel setup. Both aerosols were extensively characterized with regard to chemical and physical particle properties. The deposition was additionally estimated with the ICRP model, modified for the determined aerosol properties, in order to validate the experiments and allow a generalization of the results. The measured total deposited fraction of particles from both efficient combustion and low-temperature combustion was 0.21-0.24 by number, surface, and mass. The deposition behavior can be explained by the size distributions of the particles and by their ability to grow by water uptake in the lungs, where the relative humidity is close to saturation. The experiments were in basic agreement with the model calculations. Our findings illustrate: (1) that particles from biomass combustion obtain a size in the respiratory tract at which the deposition probability is close to its minimum, (2) that particle water absorption has substantial impact on deposition, and (3) that deposition is markedly influenced by individual factors.

Metal and silicate particles including nanoparticles are present in electronic cigarette cartomizer fluid and aerosol.

Directory of Open Access Journals (Sweden)

Monique Williams

Full Text Available Electronic cigarettes (EC deliver aerosol by heating fluid containing nicotine. Cartomizer EC combine the fluid chamber and heating element in a single unit. Because EC do not burn tobacco, they may be safer than conventional cigarettes. Their use is rapidly increasing worldwide with little prior testing of their aerosol.We tested the hypothesis that EC aerosol contains metals derived from various components in EC.Cartomizer contents and aerosols were analyzed using light and electron microscopy, cytotoxicity testing, x-ray microanalysis, particle counting, and inductively coupled plasma optical emission spectrometry.The filament, a nickel-chromium wire, was coupled to a thicker copper wire coated with silver. The silver coating was sometimes missing. Four tin solder joints attached the wires to each other and coupled the copper/silver wire to the air tube and mouthpiece. All cartomizers had evidence of use before packaging (burn spots on the fibers and electrophoretic movement of fluid in the fibers. Fibers in two cartomizers had green deposits that contained copper. Centrifugation of the fibers produced large pellets containing tin. Tin particles and tin whiskers were identified in cartridge fluid and outer fibers. Cartomizer fluid with tin particles was cytotoxic in assays using human pulmonary fibroblasts. The aerosol contained particles >1 µm comprised of tin, silver, iron, nickel, aluminum, and silicate and nanoparticles (<100 nm of tin, chromium and nickel. The concentrations of nine of eleven elements in EC aerosol were higher than or equal to the corresponding concentrations in conventional cigarette smoke. Many of the elements identified in EC aerosol are known to cause respiratory distress and disease.The presence of metal and silicate particles in cartomizer aerosol demonstrates the need for improved quality control in EC design and manufacture and studies on how EC aerosol impacts the health of users and bystanders.

Metal and silicate particles including nanoparticles are present in electronic cigarette cartomizer fluid and aerosol.

Science.gov (United States)

Williams, Monique; Villarreal, Amanda; Bozhilov, Krassimir; Lin, Sabrina; Talbot, Prue

2013-01-01

Electronic cigarettes (EC) deliver aerosol by heating fluid containing nicotine. Cartomizer EC combine the fluid chamber and heating element in a single unit. Because EC do not burn tobacco, they may be safer than conventional cigarettes. Their use is rapidly increasing worldwide with little prior testing of their aerosol. We tested the hypothesis that EC aerosol contains metals derived from various components in EC. Cartomizer contents and aerosols were analyzed using light and electron microscopy, cytotoxicity testing, x-ray microanalysis, particle counting, and inductively coupled plasma optical emission spectrometry. The filament, a nickel-chromium wire, was coupled to a thicker copper wire coated with silver. The silver coating was sometimes missing. Four tin solder joints attached the wires to each other and coupled the copper/silver wire to the air tube and mouthpiece. All cartomizers had evidence of use before packaging (burn spots on the fibers and electrophoretic movement of fluid in the fibers). Fibers in two cartomizers had green deposits that contained copper. Centrifugation of the fibers produced large pellets containing tin. Tin particles and tin whiskers were identified in cartridge fluid and outer fibers. Cartomizer fluid with tin particles was cytotoxic in assays using human pulmonary fibroblasts. The aerosol contained particles >1 µm comprised of tin, silver, iron, nickel, aluminum, and silicate and nanoparticles (<100 nm) of tin, chromium and nickel. The concentrations of nine of eleven elements in EC aerosol were higher than or equal to the corresponding concentrations in conventional cigarette smoke. Many of the elements identified in EC aerosol are known to cause respiratory distress and disease. The presence of metal and silicate particles in cartomizer aerosol demonstrates the need for improved quality control in EC design and manufacture and studies on how EC aerosol impacts the health of users and bystanders.

MAPPIX: A software package for off-line micro-pixe single particle aerosol analysis

International Nuclear Information System (INIS)

Ceccato, D.

2009-01-01

In the framework of a multiannual experiment performed at Baia Terra Nova, Antarctica, size-segregated aerosol samples were collected by using a 12-stage SDI impactor (Hillamo design). Approximately 2800 particles, belonging to the first four supermicrometric SDI stages - 8.39, 4.08, 2.68, 1.66 μm dynamic aerosol diameter cuts - were analyzed at the INFN-LNL micro-PIXE facility, a three lens Oxford Microprobe (OM) product, installed in the early nineties. Four regions on each of the 12 sub-samples were measured; 60 aerosol particles were detected on average in each of the analyzed regions. The off-line single aerosol particle (SAP) analysis of such big amount of data required software that is able to rapidly handle the acquired data, with a simple and fast area selection procedure; the subsequent automated PIXE spectra analysis with a specialized code was also needed. The MAPPIX 2.0 software was designed to make easier and faster the user jobs during the SAP analysis. The package is composed of two separate routines: the first one is devoted to data format conversion (OM-LMF file format to MAPPIX format), while the second one is devoted to micro-PIXE maps graphical presentation and aerosol particle selection procedure. The MAPPIX data format and software features will be discussed; a short report of the speed performances will be presented.

Glyoxal processing by aerosol multiphase chemistry: towards a kinetic modeling framework of secondary organic aerosol formation in aqueous particles

Directory of Open Access Journals (Sweden)

B. Ervens

2010-09-01

Full Text Available This study presents a modeling framework based on laboratory data to describe the kinetics of glyoxal reactions that form secondary organic aerosol (SOA in aqueous aerosol particles. Recent laboratory results on glyoxal reactions are reviewed and a consistent set of empirical reaction rate constants is derived that captures the kinetics of glyoxal hydration and subsequent reversible and irreversible reactions in aqueous inorganic and water-soluble organic aerosol seeds. Products of these processes include (a oligomers, (b nitrogen-containing products, (c photochemical oxidation products with high molecular weight. These additional aqueous phase processes enhance the SOA formation rate in particles and yield two to three orders of magnitude more SOA than predicted based on reaction schemes for dilute aqueous phase (cloud chemistry for the same conditions (liquid water content, particle size.

The application of the new module including detailed chemical processes in a box model demonstrates that both the time scale to reach aqueous phase equilibria and the choice of rate constants of irreversible reactions have a pronounced effect on the predicted atmospheric relevance of SOA formation from glyoxal. During day time, a photochemical (most likely radical-initiated process is the major SOA formation pathway forming ∼5 μg m⁻³ SOA over 12 h (assuming a constant glyoxal mixing ratio of 300 ppt. During night time, reactions of nitrogen-containing compounds (ammonium, amines, amino acids contribute most to the predicted SOA mass; however, the absolute predicted SOA masses are reduced by an order of magnitude as compared to day time production. The contribution of the ammonium reaction significantly increases in moderately acidic or neutral particles (5 < pH < 7.

Glyoxal uptake into ammonium sulfate seed under dark conditions can be represented with a single reaction parameter k_effupt that does not depend

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

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

Formation of secondary organic aerosol coating on black carbon particles near vehicular emissions

Science.gov (United States)

Lee, Alex K. Y.; Chen, Chia-Li; Liu, Jun; Price, Derek J.; Betha, Raghu; Russell, Lynn M.; Zhang, Xiaolu; Cappa, Christopher D.

2017-12-01

Black carbon (BC) emitted from incomplete combustion can result in significant impacts on air quality and climate. Understanding the mixing state of ambient BC and the chemical characteristics of its associated coatings is particularly important to evaluate BC fate and environmental impacts. In this study, we investigate the formation of organic coatings on BC particles in an urban environment (Fontana, California) under hot and dry conditions using a soot-particle aerosol mass spectrometer (SP-AMS). The SP-AMS was operated in a configuration that can exclusively detect refractory BC (rBC) particles and their coatings. Using the -log(NOx / NOy) ratio as a proxy for photochemical age of air masses, substantial formation of secondary organic aerosol (SOA) coatings on rBC particles was observed due to active photochemistry in the afternoon, whereas primary organic aerosol (POA) components were strongly associated with rBC from fresh vehicular emissions in the morning rush hours. There is also evidence that cooking-related organic aerosols were externally mixed from rBC. Positive matrix factorization and elemental analysis illustrate that most of the observed SOA coatings were freshly formed, providing an opportunity to examine SOA coating formation on rBCs near vehicular emissions. Approximately 7-20 wt % of secondary organic and inorganic species were estimated to be internally mixed with rBC on average, implying that rBC is unlikely the major condensation sink of SOA in this study. Comparison of our results to a co-located standard high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) measurement suggests that at least a portion of SOA materials condensed on rBC surfaces were chemically different from oxygenated organic aerosol (OOA) particles that were externally mixed with rBC, although they could both be generated from local photochemistry.

Hygroscopic Properties and Chemical Composition of Aerosol Particles at the High Alpine Site Jungfraujoch

Energy Technology Data Exchange (ETDEWEB)

Weingarter, E.; Gysel, M.; Sjoegren, S.; Baltesperger, U.; Alfarra, R.; Bower, K.; Coe, H.

2004-03-01

The hygroscopic properties of aerosols play a significant role in atmospheric phenomena such as acid deposition, visibility degradation and climate change. Due to the hygroscopic growth of the particles, water is often the dominant component of the ambient aerosol at high relative humidity (RH) conditions. The ability to absorb water depends on the particle chemical composition, dry size, and shape. The aim of this study is to link the chemical composition of the atmospheric aerosol to its hygroscopic properties. (author)

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.

The impact of aerosol composition on the particle to gas partitioning of reactive mercury.

Science.gov (United States)

Rutter, Andrew P; Schauer, James J

2007-06-01

A laboratory system was developed to study the gas-particle partitioning of reactive mercury (RM) as a function of aerosol composition in synthetic atmospheric particulate matter. The collection of RM was achieved by filter- and sorbent-based methods. Analyses of the RM collected on the filters and sorbents were performed using thermal extraction combined with cold vapor atomic fluorescence spectroscopy (CVAFS), allowing direct measurement of the RM load on the substrates. Laboratory measurements of the gas-particle partitioning coefficients of RM to atmospheric aerosol particles revealed a strong dependence on aerosol composition, with partitioning coefficients that varied by orders of magnitude depending on the composition of the particles. Particles of sodium nitrate and the chlorides of potassium and sodium had high partitioning coefficients, shifting the RM partitioning toward the particle phase, while ammonium sulfate, levoglucosan, and adipic acid caused the RM to partition toward the gas phase and, therefore, had partitioning coefficients that were lower by orders of magnitude.

Compact and portable system for evaluation of individual exposure at aerosol particle in urban area

International Nuclear Information System (INIS)

De Zaiacomo, T.

1995-01-01

A compact and portable system for real-time acquisition of aerosol concentration data in urban and extra-urban area is presented. It is based on two optical type aerosol monitors integrated by aerosol particle separating and collecting devices, assembled into a carrying case together with temperature and relative humidity sensors and a programmable analog data logger; data output is addressed to a dedicated printer or personal computer. Further data about particle size, morphological aspect and particle mass concentration are obtainable by weighing supports used to concurrently collect aerosol particles and/or by means of microanalytical techniques. System performances are evaluated from the point of view of portability, possibility of use as stationary sampler for long-term monitoring purposes and coherence between optical response and ponderal mass. Some tests are finally carried out, to investigate the effect of relative humidity on the optical response of this type of instruments

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.

Gas-particle partitioning of semivolatile organic compounds (SOCs) on mixtures of aerosols in a smog chamber.

Science.gov (United States)

Chandramouli, Bharadwaj; Jang, Myoseon; Kamens, Richard M

2003-09-15

The partitioning behavior of a set of diverse SOCs on two and three component mixtures of aerosols from different sources was studied using smog chamber experimental data. A set of SOCs of different compound types was introduced into a system containing a mixture of aerosols from two or more sources. Gas and particle samples were taken using a filter-filter-denuder sampling system, and a partitioning coefficient Kp was estimated using Kp = Cp/(CgTSP). Particle size distributions were measured using a differential mobility analyzer and a light scattering detector. Gas and particle samples were analyzed using GCMS. The aerosol composition in the chamber was tracked chemically using a combination of signature compounds and the organic matter mass fraction (f(om)) of the individual aerosol sources. The physical nature of the aerosol mixture in the chamber was determined using particle size distributions, and an aggregate Kp was estimated from theoretically calculated Kp on the individual sources. Model fits for Kp showed that when the mixture involved primary sources of aerosol, the aggregate Kp of the mixture could be successfully modeled as an external mixture of the Kp on the individual aerosols. There were significant differences observed for some SOCs between modeling the system as an external and as an internal mixture. However, when one of the aerosol sources was secondary, the aggregate model Kp required incorporation of the secondary aerosol products on the preexisting aerosol for adequate model fits. Modeling such a system as an external mixture grossly overpredicted the Kp of alkanes in the mixture. Indirect evidence of heterogeneous, acid-catalyzed reactions in the particle phase was also seen, leading to a significant increase in the polarity of the resulting aerosol mix and a resulting decrease in the observed Kp of alkanes in the chamber. The model was partly consistent with this decrease but could not completely explain the reduction in Kp because of

Hygroscopic behaviour of aerosol particles emitted from biomass fired grate boilers

Energy Technology Data Exchange (ETDEWEB)

Rissler, Jenny; Swietlicki, Erik [Lund Univ. (Sweden). Div. of Nuclear Physics; Pagels, Joakim; Wierzbicka, Aneta; Bohgard, Mats [Lund Univ. (Sweden). Div. of Ergonomics and Aerosol Technology; Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Bioenergy Technology

2005-02-01

This study focuses on the hygroscopic properties of sub-micrometer aerosol particles emitted from two small-scale district heating combustion plants (1 and 1.5 MW) burning two types of biomass fuels (moist forest residue and pellets). The hygroscopic particle diameter growth was measured when taken from a dehydrated to a humidified state for particle diameters between 30-350 nm (dry size) using a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA). Particles of a certain dry size all showed similar hygroscopic growth and the average diameter growth at RH=90% for 110/100 nm particles was 1.68 in the 1 MW boiler, and 1.52 in the 1.5 MW boiler. These growth factors are considerably higher in comparison to other combustion aerosol particles such as diesel exhaust, and are the result of the efficient combustion and the high concentration of alkali species in the fuel. The observed water uptake could be explained using the Zdanovskii-Stokes-Robinson (ZSR) mixing rule and a chemical composition of only potassium salts, taken from an Ion Chromatography analysis of filter sample (KCl, K{sub 2}SO{sub 4}, and K{sub 2}CO{sub 3}). Agglomerated particles collapsed and became more spherical when initially exposed to a moderately high relative humidity. When diluting with hot particle-free air, the fractal-like structures remained intact until humidified in the HTDMA. A method is presented to by which to estimate the fractal dimension of the agglomerated combustion aerosol and correct the measured mobility diameter hygroscopic growth to the more useful property volume growth. The fractal dimension was estimated to be {approx}2.5.

Hygroscopic behaviour of aerosol particles emitted from biomass fired grate boilers

International Nuclear Information System (INIS)

Rissler, Jenny; Swietlicki, Erik; Pagels, Joakim; Wierzbicka, Aneta; Bohgard, Mats; Strand, Michael; Lillieblad, Lena; Sanati, Mehri

2005-01-01

This study focuses on the hygroscopic properties of sub-micrometer aerosol particles emitted from two small-scale district heating combustion plants (1 and 1.5 MW) burning two types of biomass fuels (moist forest residue and pellets). The hygroscopic particle diameter growth was measured when taken from a dehydrated to a humidified state for particle diameters between 30-350 nm (dry size) using a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA). Particles of a certain dry size all showed similar hygroscopic growth and the average diameter growth at RH=90% for 110/100 nm particles was 1.68 in the 1 MW boiler, and 1.52 in the 1.5 MW boiler. These growth factors are considerably higher in comparison to other combustion aerosol particles such as diesel exhaust, and are the result of the efficient combustion and the high concentration of alkali species in the fuel. The observed water uptake could be explained using the Zdanovskii-Stokes-Robinson (ZSR) mixing rule and a chemical composition of only potassium salts, taken from an Ion Chromatography analysis of filter sample (KCl, K 2 SO 4 , and K 2 CO 3 ). Agglomerated particles collapsed and became more spherical when initially exposed to a moderately high relative humidity. When diluting with hot particle-free air, the fractal-like structures remained intact until humidified in the HTDMA. A method is presented to by which to estimate the fractal dimension of the agglomerated combustion aerosol and correct the measured mobility diameter hygroscopic growth to the more useful property volume growth. The fractal dimension was estimated to be ∼2.5

Study of Cl containing urban aerosol particles by ion beam analytical methods

International Nuclear Information System (INIS)

Angyal, A.; Kertesz, Zs.; Szikszai, Z.; Szoboszlai, T.

2009-01-01

Complete text of publication follows. In the densely populated areas of Europe one of the most important environmental problems is aerosol pollution. Thus one of the main goals of atmospheric research is to determine aerosol sources. In order to identify the origin of the particles, the knowledge of the chemical composition and size distribution is demanded. As a result of a source apportionment study, several sources of fine (particles with aerodynamic diameter < 2.5 μm) and coarse (10 μm ≥ aerodynamic diameter ≥ 2.5 μm) urban particulate matter were identified in Debrecen, using the hourly evolution of the elemental components. Sources characterized by high chlorine content were found in both size fractions, which gave significant contribution to the aerosol concentration in Debrecen. However, the origin of these particles could not be identified on the available information. In this work we give a more accurate characterization of the sources of coarse-mode Cl by using single particle analysis. Aerosol samples with 2-3 hours time resolution were collected in the frame of sampling campaigns in the garden of ATOMKI between October 2007 and January 2009. The elemental composition (for Z ≥ 13) was determined by Particle Induced X-ray Emission (PIXE). Single particle analysis of chosen samples was done on the ATOMKI Scanning Nuclear Microprobe Facility. Morphology, size and elemental composition for Z ≥ 6 of around 1000 coarse mode particles were determined by Scanning Transmission Ion Microscopy, light element PIXE and PIXE analytical methods. Hierarchical cluster analysis was performed on the data set to group the particles. In order to determine the possible sources of Cl in the coarse mode, the correlation between Cl and other elements, which could be used as tracers of different sources, was examined. Cl showed very strong correlation with Na. However the Cl:Na ratio was found to be different for different episodes indicating different origin of these

Toward Quantifying the Mass-Based Hygroscopicity of Individual Submicron Atmospheric Aerosol Particles with STXM/NEXAFS and SEM/EDX

Science.gov (United States)

Yancey Piens, D.; Kelly, S. T.; OBrien, R. E.; Wang, B.; Petters, M. D.; Laskin, A.; Gilles, M. K.

2014-12-01

The hygroscopic behavior of atmospheric aerosols influences their optical and cloud-nucleation properties, and therefore affects climate. Although changes in particle size as a function of relative humidity have often been used to quantify the hygroscopic behavior of submicron aerosol particles, it has been noted that calculations of hygroscopicity based on size contain error due to particle porosity, non-ideal volume additivity and changes in surface tension. We will present a method to quantify the hygroscopic behavior of submicron aerosol particles based on changes in mass, rather than size, as a function of relative humidity. This method results from a novel experimental approach combining scanning transmission x-ray microscopy with near-edge x-ray absorption fine spectroscopy (STXM/NEXAFS), as well as scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM/EDX) on the same individual particles. First, using STXM/NEXAFS, our methods are applied to aerosol particles of known composition ‒ for instance ammonium sulfate, sodium bromide and levoglucosan ‒ and validated by theory. Then, using STXM/NEXAFS and SEM/EDX, these methods are extended to mixed atmospheric aerosol particles collected in the field at the DOE Atmospheric Radiation Measurement (ARM) Climate Research Facility at the Southern Great Planes sampling site in Oklahoma, USA. We have observed and quantified a range of hygroscopic behaviors which are correlated to the composition and morphology of individual aerosol particles. These methods will have implications for parameterizing aerosol mixing state and cloud-nucleation activity in atmospheric models.

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

On the unification of aircraft ultrafine particle emission data

Energy Technology Data Exchange (ETDEWEB)

Kaercher, B.; Busen, R. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere; Turco, R.P.; Yu Fangqun [California Univ., Los Angeles, CA (United States). Dept. of Atmospheric Sciences; Danilin, M.Y.; Weisenstein, D.K. [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States); Miake-Lye, R.C. [Aerodyne Research, Inc., Billerica, MA (United States)

2000-03-01

To predict the environmental impacts of future commercial aviation, intensive studies have been launched to measure the properties and effects of aircraft emissions. These observations have revealed an extremely wide variance with respect to the number and sizes of the particles produced in the exhaust plumes. Aircraft aerosol ultimately contributes to the population of cloud-forming nuclei, and may lead to significant global radiative and chemical perturbations. In this paper, recent discoveries are coordinated and unified in the form of a physically consistent plume aerosol model that explains most of the observational variance. Using this new approach, it is now practical to carry out reliable global atmospheric simulations of aircraft effects, as demonstrated by a novel assessment of the perturbation of the stratospheric aerosol layer by a supersonic aircraft fleet. (orig.)

Hygroscopic properties of smoke-generated organic aerosol particles emitted in the marine atmosphere

Directory of Open Access Journals (Sweden)

A. Wonaschütz

2013-10-01

Full Text Available During the Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE, a plume of organic aerosol was produced by a smoke generator and emitted into the marine atmosphere from aboard the R/V Point Sur. In this study, the hygroscopic properties and the chemical composition of the plume were studied at plume ages between 0 and 4 h in different meteorological conditions. In sunny conditions, the plume particles had very low hygroscopic growth factors (GFs: between 1.05 and 1.09 for 30 nm and between 1.02 and 1.1 for 150 nm dry size at a relative humidity (RH of 92%, contrasted by an average marine background GF of 1.6. New particles were produced in large quantities (several 10 000 cm−3, which lead to substantially increased cloud condensation nuclei (CCN concentrations at supersaturations between 0.07 and 0.88%. Ratios of oxygen to carbon (O : C and water-soluble organic mass (WSOM increased with plume age: from −3, respectively, while organic mass fractions decreased slightly (~ 0.97 to ~ 0.94. High-resolution aerosol mass spectrometer (AMS spectra show that the organic fragment m/z 43 was dominated by C2H3O+ in the small, new particle mode and by C3H7+ in the large particle mode. In the marine background aerosol, GFs for 150 nm particles at 40% RH were found to be enhanced at higher organic mass fractions: an average GF of 1.06 was observed for aerosols with an organic mass fraction of 0.53, and a GF of 1.04 for an organic mass fraction of 0.35.

Quantification of bitumen particles in aerosol and soil samples using HP-GPC

DEFF Research Database (Denmark)

Fauser, Patrik; Tjell, Jens Christian; Mosbæk, Hans

2000-01-01

A method for identifying and quantifying bitumen particles, generated from the wear of roadway asphalts, in aerosol and soil samples has been developed. Bitumen is found to be the only contributor to airborne particles containing organic molecules with molecular weights larger than 2000 g pr. mol....... These are separated and identified using High Performance Gel Permeation Chromatography (HP-GPC) with fluorescence detection. As an additional detection method Infra Red spectrometry (IR) is employed for selected samples. The methods have been used on aerosol, soil and other samples....

Modeling Dry Deposition of Aerosol Particles on Rough Surfaces

Czech Academy of Sciences Publication Activity Database

Hussein, T.; Smolík, Jiří; Kerminen, V.-M.; Kulmala, M.

2012-01-01

Roč. 46, č. 1 (2012), s. 44-59 ISSN 0278-6826 Institutional research plan: CEZ:AV0Z40720504 Keywords : aerosol particles * dry deposition * transport Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.780, year: 2012

Ice cloud processing of ultra-viscous/glassy aerosol particles leads to enhanced ice nucleation ability

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R. Wagner

2012-09-01

Full Text Available The ice nucleation potential of airborne glassy aqueous aerosol particles has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 247 and 216 K. Four different solutes were used as proxies for oxygenated organic matter found in the atmosphere: raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA, levoglucosan, and a multi-component mixture of raffinose with five dicarboxylic acids and ammonium sulphate. Similar to previous experiments with citric acid aerosols, all particles were found to nucleate ice heterogeneously before reaching the homogeneous freezing threshold provided that the freezing cycles were started well below the respective glass transition temperatures of the compounds; this is discussed in detail in a separate article. In this contribution, we identify a further mechanism by which glassy aerosols can promote ice nucleation below the homogeneous freezing limit. If the glassy aerosol particles are probed in freezing cycles started only a few degrees below their respective glass transition temperatures, they enter the liquid regime of the state diagram upon increasing relative humidity (moisture-induced glass-to-liquid transition before being able to act as heterogeneous ice nuclei. Ice formation then only occurs by homogeneous freezing at elevated supersaturation levels. When ice forms the remaining solution freeze concentrates and re-vitrifies. If these ice cloud processed glassy aerosol particles are then probed in a second freezing cycle at the same temperature, they catalyse ice formation at a supersaturation threshold between 5 and 30% with respect to ice. By analogy with the enhanced ice nucleation ability of insoluble ice nuclei like mineral dusts after they nucleate ice once, we refer to this phenomenon as pre-activation. We propose a number of possible explanations for why glassy aerosol particles that have re

Sub-micrometer refractory carbonaceous particles in the polar stratosphere

Science.gov (United States)

Schütze, Katharina; Wilson, James Charles; Weinbruch, Stephan; Benker, Nathalie; Ebert, Martin; Günther, Gebhard; Weigel, Ralf; Borrmann, Stephan

2017-10-01

Eleven particle samples collected in the polar stratosphere during SOLVE (SAGE III Ozone loss and validation experiment) from January until March 2000 were characterized in detail by high-resolution transmission and scanning electron microscopy (TEM/SEM) combined with energy-dispersive X-ray microanalysis. A total of 4202 particles (TEM = 3872; SEM = 330) were analyzed from these samples, which were collected mostly inside the polar vortex in the altitude range between 17.3 and 19.9 km. Particles that were volatile in the microscope beams contained ammonium sulfates and hydrogen sulfates and dominated the samples. Some particles with diameters ranging from 20 to 830 nm were refractory in the electron beams. Carbonaceous particles containing additional elements to C and O comprised from 72 to 100 % of the refractory particles. The rest were internal mixtures of these materials with sulfates. The median number mixing ratio of the refractory particles, expressed in units of particles per milligram of air, was 1.1 (mg air)-1 and varied between 0.65 and 2.3 (mg air)-1. Most of the refractory carbonaceous particles are completely amorphous, a few of the particles are partly ordered with a graphene sheet separation distance of 0.37 ± 0.06 nm (mean value ± standard deviation). Carbon and oxygen are the only detected major elements with an atomic O/C ratio of 0.11 ± 0.07. Minor elements observed include Si, S, Fe, Cr and Ni with the following atomic ratios relative to C: Si/C: 0.010 ± 0.011; S/C: 0.0007 ± 0.0015; Fe/C: 0.0052 ± 0.0074; Cr/C: 0.0012 ± 0.0017; Ni/C: 0.0006 ± 0.0011 (all mean values ± standard deviation).High-resolution element distribution images reveal that the minor elements are distributed within the carbonaceous matrix; i.e., heterogeneous inclusions are not observed. No difference in size, nanostructure and elemental composition was found between particles collected inside and outside the polar vortex. Based on chemistry and nanostructure

Size distribution and hygroscopic properties of aerosol particles from dry-season biomass burning in Amazonia

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J. Rissler

2006-01-01

Full Text Available Aerosol particle number size distributions and hygroscopic properties were measured at a pasture site in the southwestern Amazon region (Rondonia. The measurements were performed 11 September-14 November 2002 as part of LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia - SMOke aerosols, Clouds, rainfall and Climate, and cover the later part of the dry season (with heavy biomass burning, a transition period, and the onset of the wet period. Particle number size distributions were measured with a DMPS (Differential Mobility Particle Sizer, 3-850nm and an APS (Aerodynamic Particle Sizer, extending the distributions up to 3.3 µm in diameter. An H-TDMA (Hygroscopic Tandem Differential Mobility Analyzer measured the hygroscopic diameter growth factors (Gf at 90% relative humidity (RH, for particles with dry diameters (dp between 20-440 nm, and at several occasions RH scans (30-90% RH were performed for 165nm particles. These data provide the most extensive characterization of Amazonian biomass burning aerosol, with respect to particle number size distributions and hygroscopic properties, presented until now. The evolution of the convective boundary layer over the course of the day causes a distinct diel variation in the aerosol physical properties, which was used to get information about the properties of the aerosol at higher altitudes. The number size distributions averaged over the three defined time periods showed three modes; a nucleation mode with geometrical median diameters (GMD of ~12 nm, an Aitken mode (GMD=61-92 nm and an accumulation mode (GMD=128-190 nm. The two larger modes were shifted towards larger GMD with increasing influence from biomass burning. The hygroscopic growth at 90% RH revealed a somewhat external mixture with two groups of particles; here denoted nearly hydrophobic (Gf~1.09 for 100 nm particles and moderately hygroscopic (Gf~1.26. While the hygroscopic growth factors were surprisingly similar over the

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

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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.

The penetration of fibrous media by aerosols as a function of particle size

Energy Technology Data Exchange (ETDEWEB)

Dyment, J.

1963-11-15

This paper is concerned with the accurate experimental determination of the penetration of fibrous filter media by aerosols as a function of particle size, a topic about which previous papers give partial and conflicting data. in the present work, a heterogeneous sodium chloride aerosol was sampled before and after passing through the glass fiber filter medium by means of an electrostatic precipitator and the samples were examined under the electron microscope; the relation between particle size and penetration was derives at different gas velocities by comparison of the size distribution of the filtered and unfiltered clouds. As an extension of this work, size analyses have been made of plutonium aerosols occurring in glove boxes and enclosures during typical working operations. This information is considered in relation to the penetration of plutonium and other high density aerosol materials through filters. (auth)

A semi-empirical model for mesospheric and stratospheric NOy produced by energetic particle precipitation

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B. Funke

2016-07-01

Full Text Available The MIPAS Fourier transform spectrometer on board Envisat has measured global distributions of the six principal reactive nitrogen (NOy compounds (HNO3, NO2, NO, N2O5, ClONO2, and HNO4 during 2002–2012. These observations were used previously to detect regular polar winter descent of reactive nitrogen produced by energetic particle precipitation (EPP down to the lower stratosphere, often called the EPP indirect effect. It has further been shown that the observed fraction of NOy produced by EPP (EPP-NOy has a nearly linear relationship with the geomagnetic Ap index when taking into account the time lag introduced by transport. Here we exploit these results in a semi-empirical model for computation of EPP-modulated NOy densities and wintertime downward fluxes through stratospheric and mesospheric pressure levels. Since the Ap dependence of EPP-NOy is distorted during episodes of strong descent in Arctic winters associated with elevated stratopause events, a specific parameterization has been developed for these episodes. This model accurately reproduces the observations from MIPAS and is also consistent with estimates from other satellite instruments. Since stratospheric EPP-NOy depositions lead to changes in stratospheric ozone with possible implications for climate, the model presented here can be utilized in climate simulations without the need to incorporate many thermospheric and upper mesospheric processes. By employing historical geomagnetic indices, the model also allows for reconstruction of the EPP indirect effect since 1850. We found secular variations of solar cycle-averaged stratospheric EPP-NOy depositions on the order of 1 GM. In particular, we model a reduction of the EPP-NOy deposition rate during the last 3 decades, related to the coincident decline of geomagnetic activity that corresponds to 1.8 % of the NOy production rate by N2O oxidation. As the decline of the geomagnetic activity level is expected to continue in the

In-situ observations of interstitial aerosol particles and cloud residues found in contrails

Energy Technology Data Exchange (ETDEWEB)

Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology

1997-12-31

In spring 1994 a series of flights were conducted in cirrus clouds and contrails over southern Germany. One of the aims of this campaign was to study the phase partitioning of aerosols and water in these clouds. To achieve this separation of particles two complementary sampling probes were mounted on the research aircraft Falcon. These are the Counterflow Virtual Impactor (CVI) or super-micrometer inlet, and the interstitial inlet or submicrometer inlet. The CVI is a device that inertially separates cloud elements larger than a certain aerodynamic size from the surrounding atmosphere into a warm, dry and particle free air. Assuming that each cloud element leaves behind only one residue particle, these measurements yield an equivalent number concentration for cloud particles having an aerodynamic diameter larger than the lower cut size of the CVI. The size distribution of the sampled aerosol and residual particles between 0.1 to 3.5 {mu}m diameter was measured by a PMS PCASP (Passive Cavity Aerosol Spectrometer) working alternatively on both inlets. The gas-phase water vapor content was measured by a cryogenic frost point mirror. (R.P.) 4 refs.

In-situ observations of interstitial aerosol particles and cloud residues found in contrails

Energy Technology Data Exchange (ETDEWEB)

Stroem, J [Stockholm Univ. (Sweden). Dept. of Meteorology

1998-12-31

In spring 1994 a series of flights were conducted in cirrus clouds and contrails over southern Germany. One of the aims of this campaign was to study the phase partitioning of aerosols and water in these clouds. To achieve this separation of particles two complementary sampling probes were mounted on the research aircraft Falcon. These are the Counterflow Virtual Impactor (CVI) or super-micrometer inlet, and the interstitial inlet or submicrometer inlet. The CVI is a device that inertially separates cloud elements larger than a certain aerodynamic size from the surrounding atmosphere into a warm, dry and particle free air. Assuming that each cloud element leaves behind only one residue particle, these measurements yield an equivalent number concentration for cloud particles having an aerodynamic diameter larger than the lower cut size of the CVI. The size distribution of the sampled aerosol and residual particles between 0.1 to 3.5 {mu}m diameter was measured by a PMS PCASP (Passive Cavity Aerosol Spectrometer) working alternatively on both inlets. The gas-phase water vapor content was measured by a cryogenic frost point mirror. (R.P.) 4 refs.

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

A unified approach to infrared aerosol remote sensing and type specification

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L. Clarisse

2013-02-01

Full Text Available Atmospheric aerosols impact air quality and global climate. Space based measurements are the best way to observe their spatial and temporal distributions, and can also be used to gain better understanding of their chemical, physical and optical properties. Aerosol composition is the key parameter affecting the refractive index, which determines how much radiation is scattered and absorbed. Composition of aerosols is unfortunately not measured by state of the art satellite remote sounders. Here we use high resolution infrared measurements for aerosol type differentiation, exploiting, in that part of spectrum, the dependency of their refractive index on wavelength. We review existing detection methods and present a unified detection method based on linear discrimination analysis. We demonstrate this method on measurements of the Infrared Atmospheric Sounding Interferometer (IASI and five different aerosol types, namely volcanic ash, windblown sand, sulfuric acid droplets, ammonium sulfate and smoke particles. We compare these with traditional MODIS AOD measurements. The detection of the last three types is unprecedented in the infrared in nadir mode, but is very promising, especially for sulfuric acid droplets which are detected in the lower troposphere and up to 6 months after injection in the upper troposphere/lower stratosphere.

Radiative forcing from particle emissions by future supersonic aircraft

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G. Pitari

2008-07-01

Full Text Available In this work we focus on the direct radiative forcing (RF of black carbon (BC and sulphuric acid particles emitted by future supersonic aircraft, as well as on the ozone RF due to changes produced by emissions of both gas species (NO_x, H₂O and aerosol particles capable of affecting stratospheric ozone chemistry. Heterogeneous chemical reactions on the surface of sulphuric acid stratospheric particles (SSA-SAD are the main link between ozone chemistry and supersonic aircraft emissions of sulphur precursors (SO₂ and particles (H₂O–H₂SO₄. Photochemical O₃ changes are compared from four independent 3-D atmosphere-chemistry models (ACMs, using as input the perturbation of SSA-SAD calculated in the University of L'Aquila model, which includes on-line a microphysics code for aerosol formation and growth. The ACMs in this study use aircraft emission scenarios for the year 2050 developed by AIRBUS as a part of the EU project SCENIC, assessing options for fleet size, engine technology (NO_x emission index, Mach number, range and cruising altitude. From our baseline modeling simulation, the impact of supersonic aircraft on sulphuric acid aerosol and BC mass burdens is 53 and 1.5 μg/m², respectively, with a direct RF of −11.4 and 4.6 mW/m² (net RF=−6.8 mW/m². This paper discusses the similarities and differences amongst the participating models in terms of changes to O₃ precursors due to aircraft emissions (NO_x, HO_x,Cl_x,Br_x and the stratospheric ozone sensitivity to them. In the baseline case, the calculated global ozone change is −0.4 ±0.3 DU, with a net radiative forcing (IR+UV of −2.5± 2 mW/m². The fraction of this O₃-RF attributable to SSA-SAD changes is, however, highly variable among the models, depending on the NO_x removal

Identification of sources of aerosol particles in three locations in eastern Botswana

Science.gov (United States)

Chimidza, S.; Moloi, K.

2000-07-01

Airborne particles have been collected using a dichotomous virtual impactor at three different locations in the eastern part of Botswana: Serowe, Selibe-Phikwe, and Francistown. The particles were separated into two fractions (fine and coarse). Sampling at the three locations was done consecutively during the months of July and August, which are usually dry and stable. The sampling time for each sample was 12 hours during the day. For elemental composition, energy-dispersive x-ray fluorescence technique was used. Correlations and principal component analysis with varimax rotation were used to identify major sources of aerosol particles. In all the three places, soil was found to be the main source of aerosol particles. A copper-nickel mine and smelter at Selibe-Phikwe was found to be not only a source of copper and nickel particles in Selibe-Phikwe but also a source of these particles in far places like Serowe. In Selibe-Phikwe and Francistown, car exhaust was found to be the major source of fine particles of lead and bromine.

Radon decay products and 10-1100 nm aerosol particles in Postojna Cave

Science.gov (United States)

Bezek, M.; Gregorič, A.; Vaupotič, J.

2013-03-01

At the lowest point along the tourist route in Postojna Cave, the activity concentration of radon (222Rn) decay products and the number concentration and size distribution of aerosol particles in the size range of 10-1100 nm were monitored, with the focus on the unattached fraction (fun) of radon decay products (RnDPs), a key parameter in radon dosimetry. The total number concentration of aerosols during visits in summer was lower (700 cm-3) than in winter (2800 cm-3), and was dominated by 50 nm particles (related to the attached RnDPs) in winter. This explains the higher fun values in summer (0.75) and the lower winter measurement (0.04) and, consequently, DCFD values of 43.6 and 13.1 mSv WLM-1 respectively for the calculated dose conversion factors. The difference is caused by an enhanced inflow of fresh outside air, driven in winter by the higher air temperature in the cave compared to outside, resulting in the introduction of outside aerosol particles into the cave.

Aspects of airborne particles and radiation in the atmosphere

International Nuclear Information System (INIS)

Hidy, G.M.

1975-01-01

There are two major ways that thermal radiation may interact with airborne particles in the Earth's atmosphere. The first is a classical problem in which the radiation balance is influenced by scattering and absorption from haze or aerosol layers in the atmosphere. Absorption is generally believed to have a minor effect on attenuation of radiation compared with scattering. In the visible and infrared, scattering by submicron sized particles can have a substantial influence on the balance of radiation in the atmosphere. Considerable interest in this question has developed recently with the assessment of the global impact of air pollution in the lower atmosphere and of exhaust emissions from aircraft flying in the stratosphere. In the first part of this review, the physics of atmospheric aerosol scattering is summarized, and the current status of observational knowledge is examined to identify areas of greatest uncertainty. The second way the radiation is involved in aerosols lies in the production in the atmosphere. Until recently, evidence for airborne particle production by atmospheric photochemistry was quite ambiguous. However, with the advent of results from several new field experiments the role of photochemistry in the generation of aerosol precursors from traces of such gases as sulfur dioxide, nitrogen oxides, and olefinic hydrocarbons is much better understood. The remaining part of this paper is devoted to the discussion of several new observations that indicate the complicated nature of photochemical aerosol formation in the polluted and non-polluted atmosphere

Stable Carbon Fractionation In Size Segregated Aerosol Particles Produced By Controlled Biomass Burning

Science.gov (United States)

Masalaite, Agne; Garbaras, Andrius; Garbariene, Inga; Ceburnis, Darius; Martuzevicius, Dainius; Puida, Egidijus; Kvietkus, Kestutis; Remeikis, Vidmantas

2014-05-01

Biomass burning is the largest source of primary fine fraction carbonaceous particles and the second largest source of trace gases in the global atmosphere with a strong effect not only on the regional scale but also in areas distant from the source . Many studies have often assumed no significant carbon isotope fractionation occurring between black carbon and the original vegetation during combustion. However, other studies suggested that stable carbon isotope ratios of char or BC may not reliably reflect carbon isotopic signatures of the source vegetation. Overall, the apparently conflicting results throughout the literature regarding the observed fractionation suggest that combustion conditions may be responsible for the observed effects. The purpose of the present study was to gather more quantitative information on carbonaceous aerosols produced in controlled biomass burning, thereby having a potential impact on interpreting ambient atmospheric observations. Seven different biomass fuel types were burned under controlled conditions to determine the effect of the biomass type on the emitted particulate matter mass and stable carbon isotope composition of bulk and size segregated particles. Size segregated aerosol particles were collected using the total suspended particle (TSP) sampler and a micro-orifice uniform deposit impactor (MOUDI). The results demonstrated that particle emissions were dominated by the submicron particles in all biomass types. However, significant differences in emissions of submicron particles and their dominant sizes were found between different biomass fuels. The largest negative fractionation was obtained for the wood pellet fuel type while the largest positive isotopic fractionation was observed during the buckwheat shells combustion. The carbon isotope composition of MOUDI samples compared very well with isotope composition of TSP samples indicating consistency of the results. The measurements of the stable carbon isotope ratio in

Particle size distribution of UO sub 2 aerosols

Energy Technology Data Exchange (ETDEWEB)

Raghunath, B. (Radiation Safety Systems Div., BARC, Bombay (India)); Ramachandran, R.; Majumdar, S. (Radiometallurgy Div., BARC, Bombay (India))

1991-12-01

The Anderson cascade impactor has been used to determine the activity mean aerodynamic diameter and the particle size distribution of UO{sub 2} powders dispersed in the form of stable aerosols in an air medium. The UO{sub 2} powders obtained by the calcination of ammonium uranyl carbonate (AUC) and ammonium diuranate (ADU) precipitates have been used. (orig./MM).

Particle size dependence of biogenic secondary organic aerosol molecular composition

Science.gov (United States)

Tu, Peijun; Johnston, Murray V.

2017-06-01

Formation of secondary organic aerosol (SOA) is initiated by the oxidation of volatile organic compounds (VOCs) in the gas phase whose products subsequently partition to the particle phase. Non-volatile molecules have a negligible evaporation rate and grow particles at their condensation rate. Semi-volatile molecules have a significant evaporation rate and grow particles at a much slower rate than their condensation rate. Particle phase chemistry may enhance particle growth if it transforms partitioned semi-volatile molecules into non-volatile products. In principle, changes in molecular composition as a function of particle size allow non-volatile molecules that have condensed from the gas phase (a surface-limited process) to be distinguished from those produced by particle phase reaction (a volume-limited process). In this work, SOA was produced by β-pinene ozonolysis in a flow tube reactor. Aerosol exiting the reactor was size-selected with a differential mobility analyzer, and individual particle sizes between 35 and 110 nm in diameter were characterized by on- and offline mass spectrometry. Both the average oxygen-to-carbon (O / C) ratio and carbon oxidation state (OSc) were found to decrease with increasing particle size, while the relative signal intensity of oligomers increased with increasing particle size. These results are consistent with oligomer formation primarily in the particle phase (accretion reactions, which become more favored as the volume-to-surface-area ratio of the particle increases). Analysis of a series of polydisperse SOA samples showed similar dependencies: as the mass loading increased (and average volume-to-surface-area ratio increased), the average O / C ratio and OSc decreased, while the relative intensity of oligomer ions increased. The results illustrate the potential impact that particle phase chemistry can have on biogenic SOA formation and the particle size range where this chemistry becomes important.

Particle size dependence of biogenic secondary organic aerosol molecular composition

Directory of Open Access Journals (Sweden)

P. Tu

2017-06-01

Full Text Available Formation of secondary organic aerosol (SOA is initiated by the oxidation of volatile organic compounds (VOCs in the gas phase whose products subsequently partition to the particle phase. Non-volatile molecules have a negligible evaporation rate and grow particles at their condensation rate. Semi-volatile molecules have a significant evaporation rate and grow particles at a much slower rate than their condensation rate. Particle phase chemistry may enhance particle growth if it transforms partitioned semi-volatile molecules into non-volatile products. In principle, changes in molecular composition as a function of particle size allow non-volatile molecules that have condensed from the gas phase (a surface-limited process to be distinguished from those produced by particle phase reaction (a volume-limited process. In this work, SOA was produced by β-pinene ozonolysis in a flow tube reactor. Aerosol exiting the reactor was size-selected with a differential mobility analyzer, and individual particle sizes between 35 and 110 nm in diameter were characterized by on- and offline mass spectrometry. Both the average oxygen-to-carbon (O ∕ C ratio and carbon oxidation state (OSc were found to decrease with increasing particle size, while the relative signal intensity of oligomers increased with increasing particle size. These results are consistent with oligomer formation primarily in the particle phase (accretion reactions, which become more favored as the volume-to-surface-area ratio of the particle increases. Analysis of a series of polydisperse SOA samples showed similar dependencies: as the mass loading increased (and average volume-to-surface-area ratio increased, the average O ∕ C ratio and OSc decreased, while the relative intensity of oligomer ions increased. The results illustrate the potential impact that particle phase chemistry can have on biogenic SOA formation and the particle size range where this chemistry becomes

Optical Properties of the Urban Aerosol Particles Obtained from Ground Based Measurements and Satellite-Based Modelling Studies

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Genrik Mordas

2015-01-01

Full Text Available Applications of satellite remote sensing data combined with ground measurements and model simulation were applied to study aerosol optical properties as well as aerosol long-range transport under the impact of large scale circulation in the urban environment in Lithuania (Vilnius. Measurements included the light scattering coefficients at 3 wavelengths (450, 550, and 700 nm measured with an integrating nephelometer and aerosol particle size distribution (0.5–12 μm and number concentration (Dpa > 0.5 μm registered by aerodynamic particle sizer. Particle number concentration and mean light scattering coefficient varied from relatively low values of 6.0 cm−3 and 12.8 Mm−1 associated with air masses passed over Atlantic Ocean to relatively high value of 119 cm−3 and 276 Mm−1 associated with South-Western air masses. Analysis shows such increase in the aerosol light scattering coefficient (276 Mm−1 during the 3rd of July 2012 was attributed to a major Sahara dust storm. Aerosol size distribution with pronounced coarse particles dominance was attributed to the presence of dust particles, while resuspended dust within the urban environment was not observed.

Evaluation of Aerosol Mixing State Classes in the GISS Modele-matrix Climate Model Using Single-particle Mass Spectrometry Measurements

Science.gov (United States)

Bauer, Susanne E.; Ault, Andrew; Prather, Kimberly A.

2013-01-01

Aerosol particles in the atmosphere are composed of multiple chemical species. The aerosol mixing state, which describes how chemical species are mixed at the single-particle level, provides critical information on microphysical characteristics that determine the interaction of aerosols with the climate system. The evaluation of mixing state has become the next challenge. This study uses aerosol time-of-flight mass spectrometry (ATOFMS) data and compares the results to those of the Goddard Institute for Space Studies modelE-MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) model, a global climate model that includes a detailed aerosol microphysical scheme. We use data from field campaigns that examine a variety of air mass regimens (urban, rural, and maritime). At all locations, polluted areas in California (Riverside, La Jolla, and Long Beach), a remote location in the Sierra Nevada Mountains (Sugar Pine) and observations from Jeju (South Korea), the majority of aerosol species are internally mixed. Coarse aerosol particles, those above 1 micron, are typically aged, such as coated dust or reacted sea-salt particles. Particles below 1 micron contain large fractions of organic material, internally-mixed with sulfate and black carbon, and few external mixtures. We conclude that observations taken over multiple weeks characterize typical air mass types at a given location well; however, due to the instrumentation, we could not evaluate mass budgets. These results represent the first detailed comparison of single-particle mixing states in a global climate model with real-time single-particle mass spectrometry data, an important step in improving the representation of mixing state in global climate models.

Study of Cl-containing urban aerosol particles by ion beam analytical methods

Energy Technology Data Exchange (ETDEWEB)

Angyal, A. [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); University of Debrecen - ATOMKI, Department of Environmental Physics, H-4001 Debrecen, P.O. Box 51 (Hungary); Kertesz, Zs., E-mail: zsofi@atomki.h [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); Szikszai, Z. [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); Szoboszlai, Z. [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); University of Debrecen - ATOMKI, Department of Environmental Physics, H-4001 Debrecen, P.O. Box 51 (Hungary)

2010-06-15

Fine (aerodynamic diameter < 2.5 {mu}m) and coarse (10 {mu}m {>=} aerodynamic diameter {>=} 2.5 {mu}m) mode urban aerosol samples were collected with 2-h time resolution in the frame of several sampling campaigns between 2007 and 2009 in downtown Debrecen, East-Hungary. The elemental composition (for Z {>=} 13) of the samples was measured by particle induced X-ray emission (PIXE). On this basis sources of urban aerosol were determined by factor analysis. For both size fractions a source characterized by high chlorine content were found. However, the origin of the Cl-containing aerosol could not be ascertained. Further investigation of samples characterized with high Cl content were done on the ATOMKI Scanning Nuclear Microprobe Facility in order to determine the possible chemical composition of these particles and thus the potential sources. Morphology, size and elemental composition for Z {>=} 6 of around 1000 coarse mode particles were determined by using STIM (Scanning Transmission Ion Microscopy), light-element PIXE and PIXE analytical methods. Hierarchical cluster analysis was performed on the obtained dataset in order to group the particles; correlations between different elements were also calculated. Five possible sources of Cl were identified, from which four were anthropogenic: winter salting of streets, agriculture through fertilizers, buildings and industry; the natural group was sea-salt.

Probing the micro-rheological properties of aerosol particles using optical tweezers

International Nuclear Information System (INIS)

Power, Rory M; Reid, Jonathan P

2014-01-01

The use of optical trapping techniques to manipulate probe particles for performing micro-rheological measurements on a surrounding fluid is well-established. Here, we review recent advances made in the use of optical trapping to probe the rheological properties of trapped particles themselves. In particular, we review observations of the continuous transition from liquid to solid-like viscosity of sub-picolitre supersaturated solution aerosol droplets using optical trapping techniques. Direct measurements of the viscosity of the particle bulk are derived from the damped oscillations in shape following coalescence of two particles, a consequence of the interplay between viscous and surface forces and the capillary driven relaxation of the approximately spheroidal composite particle. Holographic optical tweezers provide a facile method for the manipulation of arrays of particles allowing coalescence to be controllably induced between two micron-sized aerosol particles. The optical forces, while sufficiently strong to confine the composite particle, are several orders of magnitude weaker than the capillary forces driving relaxation. Light, elastically back-scattered by the particle, is recorded with sub-100 ns resolution allowing measurements of fast relaxation (low viscosity) dynamics, while the brightfield image can be used to monitor the shape relaxation extending to times in excess of 1000 s. For the slowest relaxation dynamics studied (particles with the highest viscosity) the presence and line shape of whispering gallery modes in the cavity enhanced Raman spectrum can be used to infer the relaxation time while serving the dual purpose of allowing the droplet size and refractive index to be measured with accuracies of ±0.025% and ±0.1%, respectively. The time constant for the damped relaxation can be used to infer the bulk viscosity, spanning from the dilute solution limit to a value approaching that of a glass, typically considered to be >10 12 �

Probing the micro-rheological properties of aerosol particles using optical tweezers

Science.gov (United States)

Power, Rory M.; Reid, Jonathan P.

2014-07-01

The use of optical trapping techniques to manipulate probe particles for performing micro-rheological measurements on a surrounding fluid is well-established. Here, we review recent advances made in the use of optical trapping to probe the rheological properties of trapped particles themselves. In particular, we review observations of the continuous transition from liquid to solid-like viscosity of sub-picolitre supersaturated solution aerosol droplets using optical trapping techniques. Direct measurements of the viscosity of the particle bulk are derived from the damped oscillations in shape following coalescence of two particles, a consequence of the interplay between viscous and surface forces and the capillary driven relaxation of the approximately spheroidal composite particle. Holographic optical tweezers provide a facile method for the manipulation of arrays of particles allowing coalescence to be controllably induced between two micron-sized aerosol particles. The optical forces, while sufficiently strong to confine the composite particle, are several orders of magnitude weaker than the capillary forces driving relaxation. Light, elastically back-scattered by the particle, is recorded with sub-100 ns resolution allowing measurements of fast relaxation (low viscosity) dynamics, while the brightfield image can be used to monitor the shape relaxation extending to times in excess of 1000 s. For the slowest relaxation dynamics studied (particles with the highest viscosity) the presence and line shape of whispering gallery modes in the cavity enhanced Raman spectrum can be used to infer the relaxation time while serving the dual purpose of allowing the droplet size and refractive index to be measured with accuracies of ±0.025% and ±0.1%, respectively. The time constant for the damped relaxation can be used to infer the bulk viscosity, spanning from the dilute solution limit to a value approaching that of a glass, typically considered to be >1012 Pa s, whilst

Sub-micrometer refractory carbonaceous particles in the polar stratosphere

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K. Schütze

2017-10-01

Full Text Available Eleven particle samples collected in the polar stratosphere during SOLVE (SAGE III Ozone loss and validation experiment from January until March 2000 were characterized in detail by high-resolution transmission and scanning electron microscopy (TEM/SEM combined with energy-dispersive X-ray microanalysis. A total of 4202 particles (TEM  =  3872; SEM  =  330 were analyzed from these samples, which were collected mostly inside the polar vortex in the altitude range between 17.3 and 19.9 km. Particles that were volatile in the microscope beams contained ammonium sulfates and hydrogen sulfates and dominated the samples. Some particles with diameters ranging from 20 to 830 nm were refractory in the electron beams. Carbonaceous particles containing additional elements to C and O comprised from 72 to 100 % of the refractory particles. The rest were internal mixtures of these materials with sulfates. The median number mixing ratio of the refractory particles, expressed in units of particles per milligram of air, was 1.1 (mg air−1 and varied between 0.65 and 2.3 (mg air−1. Most of the refractory carbonaceous particles are completely amorphous, a few of the particles are partly ordered with a graphene sheet separation distance of 0.37 ± 0.06 nm (mean value ± standard deviation. Carbon and oxygen are the only detected major elements with an atomic O∕C ratio of 0.11 ± 0.07. Minor elements observed include Si, S, Fe, Cr and Ni with the following atomic ratios relative to C: Si∕C: 0.010 ± 0.011; S∕C: 0.0007 ± 0.0015; Fe∕C: 0.0052 ± 0.0074; Cr∕C: 0.0012 ± 0.0017; Ni∕C: 0.0006 ± 0.0011 (all mean values ± standard deviation.High-resolution element distribution images reveal that the minor elements are distributed within the carbonaceous matrix; i.e., heterogeneous inclusions are not observed. No difference in size, nanostructure and elemental composition was found between

Seasonal variations in aerosol particle composition at the puy-de-Dôme research station in France

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E. J. Freney

2011-12-01

Full Text Available Detailed investigations of the chemical and microphysical properties of atmospheric aerosol particles were performed at the puy-de-Dôme (pdD research station (1465 m in autumn (September and October 2008, winter (February and March 2009, and summer (June 2010 using a compact Time-of-Flight Aerosol Mass Spectrometer (cToF-AMS. Over the three campaigns, the average mass concentrations of the non-refractory submicron particles ranged from 10 μg m⁻³ up to 27 μg m⁻³. Highest nitrate and ammonium mass concentrations were measured during the winter and during periods when marine modified airmasses were arriving at the site, whereas highest concentrations of organic particles were measured during the summer and during periods when continental airmasses arrived at the site. The measurements reported in this paper show that atmospheric particle composition is strongly influenced by both the season and the origin of the airmass. The total organic mass spectra were analysed using positive matrix factorisation to separate individual organic components contributing to the overall organic particle mass concentrations. These organic components include a low volatility oxygenated organic aerosol particle (LV-OOA and a semi-volatile organic aerosol particle (SV-OOA. Correlations of the LV-OOA components with fragments of m/z 60 and m/z 73 (mass spectral markers of wood burning during the winter campaign suggest that wintertime LV-OOA are related to aged biomass burning emissions, whereas organic aerosol particles measured during the summer are likely linked to biogenic sources. Equivalent potential temperature calculations, gas-phase, and LIDAR measurements define whether the research site is in the planetary boundary layer (PBL or in the free troposphere (FT/residual layer (RL. We observe that SV-OOA and nitrate particles are associated with air masses arriving from the PBL where as particle composition measured from RL

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 environmental hazards and conserving our natural surroundings as far as possible. (orig.) [de

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

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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.

Mixing state of particles with secondary species by single particle aerosol mass spectrometer in an atmospheric pollution event

Science.gov (United States)

Xu, Lingling; Chen, Jinsheng

2016-04-01

Single particle aerosol mass spectrometer (SPAMS) was used to characterize size distribution, chemical composition, and mixing state of particles in an atmospheric pollution event during 20 Oct. - 5 Nov., 2015 in Xiamen, Southeast China. A total of 533,012 particle mass spectra were obtained and clustered into six groups, comprising of industry metal (4.5%), dust particles (2.6%), carbonaceous species (70.7%), K-Rich particles (20.7%), seasalt (0.6%) and other particles (0.9%). Carbonaceous species were further divided into EC (70.6%), OC (28.5%), and mixed ECOC (0.9%). There were 61.7%, 58.3%, 4.0%, and 14.6% of particles internally mixed with sulfate, nitrate, ammonium and C2H3O, respectively, indicating that these particles had undergone significant aging processing. Sulfate was preferentially mixed with carbonaceous particles, while nitrate tended to mix with metal-containing and dust particles. Compared to clear days, the fractions of EC-, metal- and dust particles remarkably increased, while the fraction of OC-containing particles decreased in pollution days. The mixing state of particles, excepted for OC-containing particles with secondary species was much stronger in pollution days than that in clear days, which revealed the significant influence of secondary particles in atmospheric pollution. The different activity of OC-containing particles might be related to their much smaller aerodynamic diameter. These results could improve our understanding of aerosol characteristics and could be helpful to further investigate the atmospheric process of particles.