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Sample records for atmospheric aerosol characterisation

  1. Mass spectrometric approaches for chemical characterisation of atmospheric aerosols: critical review of the most recent advances

    SciTech Connect

    Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey A.

    2012-06-29

    This manuscript presents an overview of the most recent instrument developments for the field and laboratory applications of mass spectrometry (MS) to investigate the chemistry and physics of atmospheric aerosols. A range of MS instruments, employing different sample introduction methods, ionisation and mass detection techniques are used both for ‘online’ and ‘offline’ characterisation of aerosols. Online MS techniques enable detection of individual particles with simultaneous measurement of particle size distributions and aerodynamic characteristics and are ideally suited for field studies that require high temporal resolution. Offline MS techniques provide a means for detailed molecular-level analysis of aerosol samples, which is essential to gain fundamental knowledge regarding aerosol chemistry, mechanisms of particle formation and atmospheric aging. Combined, complementary MS techniques provide comprehensive information on the chemical composition, size, morphology and phase of aerosols – data of key importance for evaluating hygroscopic and optical properties of particles, their health effects, understanding their origins and atmospheric evolution. Over the last few years, developments and applications of MS techniques in aerosol research have expanded remarkably as evident by skyrocketing publication statistics. Finally, the goal of this review is to present the most recent developments in the field of aerosol mass spectrometry for the time period of late 2010 to early 2012, which have not been conveyed in previous reviews.

  2. Infrared characterisation of acetonitrile and propionitrile aerosols under Titan's atmospheric conditions.

    PubMed

    Ennis, C; Auchettl, R; Ruzi, M; Robertson, E G

    2017-01-25

    Pure, crystalline acetonitrile (CH3CN) and propionitrile (CH3CH2CN) particles were formed in a collisional cooling cell allowing for infrared (IR) signatures to be compiled from 50 to 5000 cm(-1). The cell temperature and pressure conditions were controlled to simulate Titan's lower atmosphere (80-130 K and 1-100 mbar), allowing for the comparison of laboratory data to the spectra obtained from the Cassini-Huygens mission. The far-IR features confirmed the morphology of CH3CN aerosols as the metastable β-phase (monoclinic) ice, however, a specific crystalline phase for CH3CH2CN could not be verified. Mie theory and the literature complex refractive indices enabled of the experimental spectra to be modelled. The procedure yielded size distributions for CH3CN (55-140 nm) and CH3CH2CN (140-160 nm) particles. Effective kinetic profiles, tracing the evolution of aerosol band intensities, showed that condensation of CH3CH2CN proceeded at twice the rate of CH3CN aerosols. In addition, the rate of CH3CH2CN aerosol depletion via lateral diffusion of the particles from the interrogation volume was approximately 50% faster than that of CH3CN. The far-IR spectra recorded for both nitrile aerosols did not display absorption profiles that could be attributed to the unassigned 220 cm(-1) feature, which has been observed to fluctuate seasonally in the spectra obtained from Titan's atmosphere.

  3. Global Atmospheric Aerosol Modeling

    NASA Technical Reports Server (NTRS)

    Hendricks, Johannes; Aquila, Valentina; Righi, Mattia

    2012-01-01

    Global aerosol models are used to study the distribution and properties of atmospheric aerosol particles as well as their effects on clouds, atmospheric chemistry, radiation, and climate. The present article provides an overview of the basic concepts of global atmospheric aerosol modeling and shows some examples from a global aerosol simulation. Particular emphasis is placed on the simulation of aerosol particles and their effects within global climate models.

  4. The optical manipulation and characterisation of aerosol particles

    NASA Astrophysics Data System (ADS)

    Reid, Jonathan P.

    2008-08-01

    Aerosols play a crucial role in many areas of science, ranging from atmospheric chemistry and physics, to pharmaceutical aerosols and drug delivery to the lungs, to combustion science and spray drying. The development of new methods for characterising the properties and dynamics of aerosol particles is of crucial importance if the complex role that particles play is to be more fully understood. Optical tweezers provide a valuable new tool to address fundamental questions in aerosol science. Single or multiple particles 1-15 μm in diameter can be manipulated for indefinite timescales. Linear and non-linear Raman and fluorescence spectroscopies can be used to probe particle composition, phase, component mixing state, and size. In particular, size can be determined with nanometre accuracy, allowing accurate measurements of the thermodynamic properties of aerosols, the kinetics of particle transformation and of light absorption. Further, the simultaneous manipulation of multiple particles in parallel optical traps provides a method for performing comparative measurements on particles of different composition. We will present some latest work in which optical tweezers are used to characterise aerosol dynamics, demonstrating that optical tweezers can find application in studies of hygroscopicity, the mixing state of different chemical components, including the phase separation of immiscible phases, and the kinetics of chemical transformation.

  5. Atmospheric Chemistry: Nature's plasticized aerosols

    NASA Astrophysics Data System (ADS)

    Ziemann, Paul J.

    2016-01-01

    The structure of atmospheric aerosol particles affects their reactivity and growth rates. Measurements of aerosol properties over the Amazon rainforest indicate that organic particles above tropical rainforests are simple liquid drops.

  6. Atmospheric Aerosol Scattering Background Observations

    DTIC Science & Technology

    1988-06-14

    condensation nuclei in the atmosphere, Nature 51:1259- 1267. 16. Whitby , K.T. (1975) Modeling of Atmospheric Aerosol Particle Size Distribution, Prog. Rep...Meteorol. 18:501-509. 33 15. Went, F.W. (1964) The nature of Aitkin condensation nuclei In the atmosphere, Nature 51:1259- 1267. 16. Whitby . K.T. (1975

  7. Atmospheric aerosols: Their Optical Properties and Effects

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Measured properties of atmospheric aerosol particles are presented. These include aerosol size frequency distribution and complex retractive index. The optical properties of aerosols are computed based on the presuppositions of thermodynamic equilibrium and of Mie-theory.

  8. Airborne Atmospheric Aerosol Measurement System

    NASA Astrophysics Data System (ADS)

    Ahn, K.; Park, Y.; Eun, H.; Lee, H.

    2015-12-01

    It is important to understand the atmospheric aerosols compositions and size distributions since they greatly affect the environment and human health. Particles in the convection layer have been a great concern in global climate changes. To understand these characteristics satellite, aircraft, and radio sonde measurement methods have usually been used. An aircraft aerosol sampling using a filter and/or impactor was the method commonly used (Jay, 2003). However, the flight speed particle sampling had some technical limitations (Hermann, 2001). Moreover, the flight legal limit, altitude, prohibited airspace, flight time, and cost was another demerit. To overcome some of these restrictions, Tethered Balloon Package System (T.B.P.S.) and Recoverable Sonde System(R.S.S.) were developed with a very light optical particle counter (OPC), impactor, and condensation particle counter (CPC). Not only does it collect and measure atmospheric aerosols depending on altitudes, but it also monitors the atmospheric conditions, temperature, humidity, wind velocity, pressure, GPS data, during the measurement (Eun, 2013). In this research, atmospheric aerosol measurement using T.B.P.S. in Ansan area is performed and the measurement results will be presented. The system can also be mounted to an unmanned aerial vehicle (UAV) and create an aerial particle concentration map. Finally, we will present measurement data using Tethered Balloon Package System (T.B.P.S.) and R.S.S (Recoverable Sonde System).

  9. Characterisation of coated aerosols using optical tweezers and neutron reflectometry

    NASA Astrophysics Data System (ADS)

    Jones, S. H.; Ward, A.; King, M. D.

    2013-12-01

    Thin organic films are believed to form naturally on the surface of aerosols [1,2] and influence aerosol properties. Cloud condensation nuclei formation and chemical reactions such as aerosol oxidation are effected by the presence of thin films [3]. There is a requirement to characterise the physical properties of both the core aerosol and its organic film in order to fully understand the contribution of coated aerosols to the indirect effect. Two complementary techniques have been used to study the oxidation of thin organic films on the surface of aerosols; laser optical tweezers and neutron reflectometry. Micron sized polystyrene beads coated in oleic acid have been trapped in air using two counter propagating laser beams. Polystyrene beads are used as a proxy for solid aerosol. The trapped aerosol is illuminated with a white LED over a broadband wavelength range and the scattered light collected to produce a Mie spectrum [4]. Analysis of the Mie spectrum results in determination of the core polystyrene bead radius, the oleic acid film thickness and refractive index dispersion of the core and shell [5]. A flow of ozone gas can then be introduced into the aerosol environment to oxidise the thin film of oleic acid and the reaction followed by monitoring the changes in the Mie spectrum. The results demonstrate complete removal of the oleic acid film. We conclude that the use of a counter propagating optical trap combined with white light Mie spectroscopy can be used to study a range of organic films on different types of aerosols and their oxidation reactions. Neutron reflectometry has been used as a complementary technique to study the oxidation of monolayer films at the air-water interface in order to gain information on reaction kinetics. The oxidation of an oleic acid film at the air-water interface by the common tropospheric oxidant ozone has been studied using a Langmuir trough. Results indicate complete removal of the oleic acid film with ozone in agreement

  10. DOE research on atmospheric aerosols

    SciTech Connect

    Schwartz, S.E.

    1995-11-01

    Atmospheric aerosols are the subject of a significant component of research within DOE`s environmental research activities, mainly under two programs within the Department`s Environmental Sciences Division, the Atmospheric Radiation Measurement (ARM) Program and the Atmospheric Chemistry Program (ACP). Research activities conducted under these programs include laboratory experiments, field measurements, and theoretical and modeling studies. The objectives and scope of these programs are briefly summarized. The ARM Program is the Department`s major research activity focusing on atmospheric processes pertinent to understanding global climate and developing the capability of predicting global climate change in response to energy related activities. The ARM approach consists mainly of testing and improving models using long-term measurements of atmospheric radiation and controlling variables at highly instrumented sites in north central Oklahoma, in the Tropical Western Pacific, and on the North Slope of Alaska. Atmospheric chemistry research within DOE addresses primarily the issue of atmospheric response to emissions from energy-generation sources. As such this program deals with the broad topic known commonly as the atmospheric source-receptor sequence. This sequence consists of all aspects of energy-related pollutants from the time they are emitted from their sources to the time they are redeposited at the Earth`s surface.

  11. Toxicity of atmospheric aerosols on marine phytoplankton

    USGS Publications Warehouse

    Paytan, A.; Mackey, K.R.M.; Chen, Y.; Lima, I.D.; Doney, S.C.; Mahowald, N.; Labiosa, R.; Post, A.F.

    2009-01-01

    Atmospheric aerosol deposition is an important source of nutrients and trace metals to the open ocean that can enhance ocean productivity and carbon sequestration and thus influence atmospheric carbon dioxide concentrations and climate. Using aerosol samples from different back trajectories in incubation experiments with natural communities, we demonstrate that the response of phytoplankton growth to aerosol additions depends on specific components in aerosols and differs across phytoplankton species. Aerosol additions enhanced growth by releasing nitrogen and phosphorus, but not all aerosols stimulated growth. Toxic effects were observed with some aerosols, where the toxicity affected picoeukaryotes and Synechococcus but not Prochlorococcus.We suggest that the toxicity could be due to high copper concentrations in these aerosols and support this by laboratory copper toxicity tests preformed with Synechococcus cultures. However, it is possible that other elements present in the aerosols or unknown synergistic effects between these elements could have also contributed to the toxic effect. Anthropogenic emissions are increasing atmospheric copper deposition sharply, and based on coupled atmosphere-ocean calculations, we show that this deposition can potentially alter patterns of marine primary production and community structure in high aerosol, low chlorophyll areas, particularly in the Bay of Bengal and downwind of South and East Asia.

  12. Characterisation of aerosol combustible mixtures generated using condensation process

    NASA Astrophysics Data System (ADS)

    Saat, Aminuddin; Dutta, Nilabza; Wahid, Mazlan A.

    2012-06-01

    An accidental release of a liquid flammable substance might be formed as an aerosol (droplet and vapour mixture). This phenomenon might be due to high pressure sprays, pressurised liquid leaks and through condensation when hot vapour is rapidly cooled. Such phenomena require a fundamental investigation of mixture characterisation prior to any subsequent process such as evaporation and combustion. This paper describes characterisation study of droplet and vapour mixtures generated in a fan stirred vessel using condensation technique. Aerosol of isooctane mixtures were generated by expansion from initially a premixed gaseous fuel-air mixture. The distribution of droplets within the mixture was characterised using laser diagnostics. Nearly monosized droplet clouds were generated and the droplet diameter was defined as a function of expansion time. The effect of changes in pressure, temperature, fuel-air fraction and expansion ratio on droplet diameter was evaluated. It is shown that aerosol generation by expansion was influenced by the initial pressure and temperature, equivalence ratio and expansion rates. All these parameters affected the onset of condensation which in turn affected the variation in droplet diameter.

  13. Toxicity of atmospheric aerosols on marine phytoplankton

    PubMed Central

    Paytan, Adina; Mackey, Katherine R. M.; Chen, Ying; Lima, Ivan D.; Doney, Scott C.; Mahowald, Natalie; Labiosa, Rochelle; Post, Anton F.

    2009-01-01

    Atmospheric aerosol deposition is an important source of nutrients and trace metals to the open ocean that can enhance ocean productivity and carbon sequestration and thus influence atmospheric carbon dioxide concentrations and climate. Using aerosol samples from different back trajectories in incubation experiments with natural communities, we demonstrate that the response of phytoplankton growth to aerosol additions depends on specific components in aerosols and differs across phytoplankton species. Aerosol additions enhanced growth by releasing nitrogen and phosphorus, but not all aerosols stimulated growth. Toxic effects were observed with some aerosols, where the toxicity affected picoeukaryotes and Synechococcus but not Prochlorococcus. We suggest that the toxicity could be due to high copper concentrations in these aerosols and support this by laboratory copper toxicity tests preformed with Synechococcus cultures. However, it is possible that other elements present in the aerosols or unknown synergistic effects between these elements could have also contributed to the toxic effect. Anthropogenic emissions are increasing atmospheric copper deposition sharply, and based on coupled atmosphere–ocean calculations, we show that this deposition can potentially alter patterns of marine primary production and community structure in high aerosol, low chlorophyll areas, particularly in the Bay of Bengal and downwind of South and East Asia. PMID:19273845

  14. A review of atmospheric aerosol measurements

    NASA Astrophysics Data System (ADS)

    McMurry, Peter H.

    Recent developments in atmospheric aerosol measurements are reviewed. The topics included complement those covered in the recent review by Chow (JAWMA 45: 320-382, 1995) which focuses on regulatory compliance measurements and filter measurements of particulate composition. This review focuses on measurements of aerosol integral properties (total number concentration, CCN concentration, optical coefficients, etc.), aerosol physical chemical properties (density, refractive index, equilibrium water content, etc.), measurements of aerosol size distributions, and measurements of size-resolved aerosol composition. Such measurements play an essential role in studies of secondary aerosol formation by atmospheric chemical transformations and enable one to quantify the contributions of various species to effects including light scattering/absorption, health effects, dry deposition, etc. Aerosol measurement evolved from an art to a science in the 1970s following the development of instrumentation to generate monodisperse calibration aerosols of known size, composition, and concentration. While such calibration tools permit precise assessments of instrument responses to known laboratory-generated aerosols, unquantifiable uncertainties remain even when carefully calibrated instruments are used for atmospheric measurements. This is because instrument responses typically depend on aerosol properties including composition, shape, density, etc., which, for atmospheric aerosols, may vary from particle-to-particle and are often unknown. More effort needs to be made to quantify measurement accuracies that can be achieved for realistic atmospheric sampling scenarios. The measurement of organic species in atmospheric particles requires substantial development. Atmospheric aerosols typically include hundreds of organic compounds, and only a small fraction (˜10%) of these can be identified by state-of-the-art analytical methodologies. Even the measurement of the total particulate organic

  15. Thermal Infrared Radiative Forcing By Atmospheric Aerosol

    NASA Astrophysics Data System (ADS)

    Adhikari, Narayan

    The work mainly focuses on the study of thermal infrared (IR) properties of atmospheric greenhouse gases and aerosols, and the estimation of the aerosol-induced direct longwave (LW) radiative forcing in the spectral region 5-20 mum at the Earth's surface (BOA; bottom of the atmosphere) and the top of the atmosphere (TOA) in cloud-free atmospheric conditions. These objectives were accomplished by conducting case studies on clear sky, smoky, and dusty conditions that took place in the Great Basin of the USA in 2013. Both the solar and thermal IR measurements and a state-of-the-science radiative transfer model, the LBLDIS, a combination of the Line-By-Line Radiative Transfer Model and the Discrete Ordinate Radiative Transfer (DISORT) solver were employed for the study. The LW aerosol forcing is often not included in climate models because the aerosol effect on the LW is often assumed to be negligible. We lack knowledge of aerosol characteristics in the LW region, and aerosol properties exhibit high variability. We have found that the LW TOA radiative forcing due to fine mode aerosols, mainly associated with small biomass burning smoke particles, is + 0.4 W/m2 which seems to be small, but it is similar to the LW radiative forcing due to increase in CO2 concentration in the Earth's atmosphere since the preindustrial era of 1750 (+ 1.6 W/m 2). The LW radiative forcing due to coarse mode aerosols, associated with large airborne mineral dust particles, was found to be as much as + 5.02 W/m2 at the surface and + 1.71 W/m2 at the TOA. All of these significant positive values of the aerosol radiative forcing both at the BOA and TOA indicate that the aerosols have a heating effect in the LW range, which contributes to counterbalancing the cooling effect associated with the aerosol radiative forcing in the shortwave (SW) spectral region. In the meantime, we have found that LW radiative forcing by aerosols is highly sensitive to particle size and complex refractive indices of

  16. The global atmospheric loading of dust aerosols

    NASA Astrophysics Data System (ADS)

    Kok, J. F.; Ridley, D. A.; Haustein, K.; Miller, R. L.; Zhao, C.

    2015-12-01

    Mineral dust is one of the most ubiquitous aerosols in the atmosphere, with important effects on human health and the climate system. But despite its importance, the global atmospheric loading of dust has remained uncertain, with model results spanning about a factor of five. Here we constrain the particle size-resolved atmospheric dust loading and global emission rate, using a novel theoretical framework that uses experimental constraints on the optical properties and size distribution of dust to eliminate climate model errors due to assumed dust properties. We find that most climate models underestimate the global atmospheric loading and emission rate of dust aerosols.

  17. Atmospheric aerosols as prebiotic chemical reactors

    PubMed Central

    Dobson, Christopher M.; Ellison, G. Barney; Tuck, Adrian F.; Vaida, Veronica

    2000-01-01

    Aerosol particles in the atmosphere have recently been found to contain a large number of chemical elements and a high content of organic material. The latter property is explicable by an inverted micelle model. The aerosol sizes with significant atmospheric lifetimes are the same as those of single-celled organisms, and they are predicted by the interplay of aerodynamic drag, surface tension, and gravity. We propose that large populations of such aerosols could have afforded an environment, by means of their ability to concentrate molecules in a wide variety of physical conditions, for key chemical transformations in the prebiotic world. We also suggest that aerosols could have been precursors to life, since it is generally agreed that the common ancestor of terrestrial life was a single-celled organism. The early steps in some of these initial transformations should be accessible to experimental investigation. PMID:11035775

  18. Atmospheric aerosol and Doppler lidar studies

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeff; Bowdle, D. A.; Srivastava, V.; Jarzembski, M.; Cutten, D.; Mccaul, E. W., Jr.

    1991-01-01

    Experimental and theoretical studies were performed of atmospheric aerosol backscatter and atmospheric dynamics with Doppler lidar as a primary tool. Activities include field and laboratory measurement and analysis efforts. The primary focus of activities related to understanding aerosol backscatter is the GLObal Backscatter Experiment (GLOBE) program. GLOBE is a multi-element effort designed toward developing a global aerosol model to describe tropospheric clean background backscatter conditions that Laser Atmospheric Wind Sounder (LAWS) is likely to encounter. Two survey missions were designed and flown in the NASA DC-8 in November 1989 and May to June 1990 over the remote Pacific Ocean, a region where backscatter values are low and where LAWS wind measurements could make a major contribution. The instrument complement consisted of pulsed and continuous-wave (CW) CO2 gas and solid state lidars measuring aerosol backscatter, optical particle counters measuring aerosol concentration, size distribution, and chemical composition, a filter/impactor system collecting aerosol samples for subsequent analysis, and integrating nephelometers measuring visible scattering coefficients. The GLOBE instrument package and survey missions were carefully planned to achieve complementary measurements under clean background backscatter conditions.

  19. Atmospheric responses to stratospheric aerosol geoengineering

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    Stratospheric aerosol geoengineering, also called solar radiation management (SRM), involves the injection of aerosol into the stratosphere to increase the planetary albedo. It has been conceieved as a policy option in response to human-induced global warming. It is well-established from modelling studies and observations following volcanic eruptions that stratospheric sulphate aerosols cause global cooling. Some aspects of the climate response, especially those involving large-scale dynamical changes, are more uncertain. This work attempts to identify the physical mechanisms operating in the climate response to stratospheric aerosol geoengineering using idealised model experiments. The radiative forcing produced by the aerosol depends on its type (species) and size. Aerosols absorb terrestrial and solar radiation, which drives stratospheric temperature change. The stratospheric temperature change also depends on aerosol type and size. We calculate the stratospheric temperature change due to geoengineering with sulphate, titania, limestone and soot in a fixed-dynamical-heating radiative model. Sulphate produces tropical heating of up to ~6 K. Titania produces much less heating, whereas soot produces much more. Most aerosols increase the meridional temperature gradient in the lower stratosphere which, by thermal wind balance, would be expected to intensify the zonal winds in the polar vortex. An intermediate-complexity general circulation model is used to investigate the dynamical response to geoengineering aerosols. Atmospheric carbon dioxide concentrations are quadrupled. The carbon dioxide forcing is then balanced using stratospheric sulphate aerosol. We assess dynamical changes in the stratosphere, for example, the frequency of stratospheric sudden warmings and the strength of the Brewer-Dobson overturning circulation. We also assess changes in the strength and position of the tropospheric jets. We compare results for sulphate with those for titania.

  20. Ionic surface active compounds in atmospheric aerosols.

    PubMed

    Sukhapan, Jariya; Brimblecombe, Peter

    2002-04-27

    Surfactants in the atmosphere have several potential roles in atmospheric chemistry. They can form films on aqueous surfaces, which lowers the surface tension and possibly delays water evaporation and gaseous transportation across the aqueous interface. They can also increase the solubility of organic compounds in the aqueous phase. Recently, the decrease of surface tension in cloud growing droplets has been suggested as relevant to increases in the number of droplets of smaller size, potentially enhancing cloud albedo. Natural surfactants in the lung aid gas transfer and influence the dissolution rate of aerosol particles, so surfactants in atmospheric aerosols, once inhaled, may interact with pulmonary surfactants. Ambient aerosols were collected from the edge of Norwich, a small city in a largely agricultural region of England, and analysed for surfactants. Methylene blue, a conventional dye for detecting anionic surfactants, has been used as a colorimetric agent. The concentration of surfactants expressed as methylene blue active substances (MBAS) is in the range of 6-170 pmol m(-3)(air). A negative correlation with chloride aerosol indicates that these surfactants are probably not the well-known surfactants derived from marine spray. A more positive correlation with aerosol nitrate and gaseous NOx supports an association with more polluted inland air masses. The surfactants found in aerosols seem to be relatively strong acids, compared with weaker acids such as the long-chain carboxylic acids previously proposed as atmospheric surfactants. Surfactants from the oxidation of organic materials (perhaps vegetation- or soil-derived) seem a likely source of these substances in the atmosphere.

  1. Atmospheric Aerosol Properties and Climate Impacts

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Kahn, Ralph A.; Remer, Lorraine A.; Yu, Hongbin; Rind, David; Feingold, Graham; Quinn, Patricia K.; Schwartz, Stephen E.; Streets, David G.; DeCola, Phillip; Halthore, Rangasayi

    2009-01-01

    This report critically reviews current knowledge about global distributions and properties of atmospheric aerosols, as they relate to aerosol impacts on climate. It assesses possible next steps aimed at substantially reducing uncertainties in aerosol radiative forcing estimates. Current measurement techniques and modeling approaches are summarized, providing context. As a part of the Synthesis and Assessment Product in the Climate Change Science Program, this assessment builds upon recent related assessments, including the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4, 2007) and other Climate Change Science Program reports. The objectives of this report are (1) to promote a consensus about the knowledge base for climate change decision support, and (2) to provide a synthesis and integration of the current knowledge of the climate-relevant impacts of anthropogenic aerosols for policy makers, policy analysts, and general public, both within and outside the U.S government and worldwide.

  2. Atmospheric Aerosols in a Changing World

    NASA Astrophysics Data System (ADS)

    Heald, C. L.

    2015-12-01

    Aerosols in the atmosphere impact human and environmental health, visibility, and climate. Exposure to air pollution is the leading environmental cause of premature mortality world-wide. The role of aerosols on the Earth's climate represents the single largest source of uncertainty in our understanding of global radiative forcing. Tremendous strides have been made to clean up the air in recent decades, and yet poor air quality continues to plague many regions of the world, and our understanding of how global change will feedback on to aerosol sources, formation, and impacts is limited. In this talk, I will use recent results from my research group to highlight some of the key uncertainties and research topics in global aerosol lifecycle.

  3. Evolution of Organic Aerosols in the Atmosphere.

    SciTech Connect

    Jimenez, J. L.; Canagaratna, M. R.; Donahue, N. M.; Prevot, A. S. H.; Zhang, Qi; Kroll, Jesse H.; DeCarlo, Peter F.; Allan, James D.; Coe, H.; Ng, N. L.; Aiken, Allison; Docherty, Kenneth S.; Ulbrich, Ingrid M.; Grieshop, A. P.; Robinson, A. L.; Duplissy, J.; Smith, J. D.; Wilson, K. R.; Lanz, V. A.; Hueglin, C.; Sun, Y. L.; Tian, J.; Laaksonen, A.; Raatikainen, T.; Rautiainen, J.; Vaattovaara, P.; Ehn, M.; Kulmala, M.; Tomlinson, Jason M.; Collins, Donald R.; Cubison, Michael J.; Dunlea, E. J.; Huffman, John A.; Onasch, Timothy B.; Alfarra, M. R.; Williams, Paul I.; Bower, K.; Kondo, Yutaka; Schneider, J.; Drewnick, F.; Borrmann, S.; Weimer, S.; Demerjian, K.; Salcedo, D.; Cottrell, L.; Griffin, Robert; Takami, A.; Miyoshi, T.; Hatakeyama, S.; Shimono, A.; Sun, J. Y.; Zhang, Y. M.; Dzepina, K.; Kimmel, Joel; Sueper, D.; Jayne, J. T.; Herndon, Scott C.; Trimborn, Achim; Williams, L. R.; Wood, Ezra C.; Middlebrook, A. M.; Kolb, C. E.; Baltensperger, Urs; Worsnop, Douglas R.

    2009-12-11

    Organic aerosol (OA) particles affect climate forcing and human health, but their sources and evolution remain poorly characterized. We present a unifying model framework that describes the atmospheric evolution of OA and is constrained and motivated by new, high time resolution, experimental characterizations of their composition, volatility, and oxidation state. OA and OA-precursor gases evolve by becoming increasingly oxidized, less volatile, and more hygroscopic, leading to the formation of large amounts of oxygenated organic aerosol (OOA) mass that has comparable concentrations to sulfate aerosol over the Northern Hemisphere. Our new model framework captures the dynamic aging behavior observed in the atmosphere and the laboratory and can serve as a basis for improving parameterizations in regional and global models.

  4. Hygroscopic and chemical characterisation of Po Valley aerosol

    NASA Astrophysics Data System (ADS)

    Bialek, J.; Dall Osto, M.; Vaattovaara, P.; Decesari, S.; Ovadnevaite, J.; Laaksonen, A.; O'Dowd, C.

    2014-02-01

    Continental summer-time aerosol in the Italian Po Valley was characterised in terms of hygroscopic properties and the influence of chemical composition therein. Additionally, the ethanol affinity of particles was analysed. The campaign-average minima in hygroscopic growth factors (HGFs, at 90% relative humidity) occurred just before and during sunrise from 03:00 to 06:00 LT (all data are reported in the local time), but, more generally, the hygroscopicity during the whole night is very low, particularly in the smaller particle sizes. The average HGFs recorded during the low HGF period were in a range from 1.18 (for the smallest, 35nm particles) to 1.38 (for the largest, 165 nm particles). During the day, the HGF gradually increased to achieve maximum values in the early afternoon hours 12:00-15:00, reaching 1.32 for 35 nm particles and 1.46 for 165 nm particles. Two contrasting case scenarios were encountered during the measurement period: Case 1 was associated with westerly air flow moving at a moderate pace and Case 2 was associated with more stagnant, slower moving air from the north-easterly sector. Case 1 exhibited weak diurnal temporal patterns, with no distinct maximum or minimum in HGF or chemical composition, and was associated with moderate non-refractory aerosol mass concentrations (for 50% size cut at 1 μ) of the order of 4.5 μg m-3. For Case 1, organics contributed typically 50% of the mass. Case 2 was characterised by >9.5 μg m-3 total non-refractory mass (<1 μ) in the early morning hours (04:00), decreasing to ~3 μg m-3 by late morning (10:00) and exhibited strong diurnal changes in chemical composition, particularly in nitrate mass but also in total organic mass concentrations. Specifically, the concentrations of nitrate peaked at night-time, along with the concentrations of hydrocarbon-like organic aerosol (HOA) and of semi-volatile oxygenated organic aerosol (SV-OOA). In general, organic growth factors (OGFs) followed a trend which was

  5. THEMIS Observations of Atmospheric Aerosol Optical Depth

    NASA Technical Reports Server (NTRS)

    Smith, Michael D.; Bandfield, Joshua L.; Christensen, Philip R.; Richardson, Mark I.

    2003-01-01

    The Mars Odyssey spacecraft entered into Martian orbit in October 2001 and after successful aerobraking began mapping in February 2002 (approximately Ls=330 deg.). Images taken by the Thermal Emission Imaging System (THEMIS) on-board the Odyssey spacecraft allow the quantitative retrieval of atmospheric dust and water-ice aerosol optical depth. Atmospheric quantities retrieved from THEMIS build upon existing datasets returned by Mariner 9, Viking, and Mars Global Surveyor (MGS). Data from THEMIS complements the concurrent MGS Thermal Emission Spectrometer (TES) data by offering a later local time (approx. 2:00 for TES vs. approx. 4:00 - 5:30 for THEMIS) and much higher spatial resolution.

  6. Characterisation of carbonaceous aerosols from the Azorean Island of Terceira

    NASA Astrophysics Data System (ADS)

    Alves, Célia; Oliveira, Tiago; Pio, Casimiro; Silvestre, Armando J. D.; Fialho, Paulo; Barata, Filipe; Legrand, Michel

    Aerosol samples were collected from 2002 to 2003 in Terceira, one of the islands of the Azores archipelago in the north-eastern Atlantic. The atmospheric samples have been analysed for its carbonaceous content and for lipid class compounds. The major constituents that comprise plant wax are n-alkanes (C 23-C 33, with and odd-to-even carbon predominance and carbon maxima at 29 or 31), n-alkanols (C 22-C 30, even-to-odd) and n-alkanoic acids (C 22-C 30, even-to-odd), with minor amounts of n-alkanals and polycyclic biomarkers, such as phytosterols. Some alkanedioic acids and phthalates were also detected. The occurrence of short-chain homologues may indicate an additional marine source, probably introduced into the atmosphere via sea spray. Changes in the composition of the homologous series derived from terrestrial plants throughout the observation period may be related to alterations in the regional sources and transport pathways. These terrestrial lipids contributed up to 47% of the total compound mass, while the marine input was estimated to be inferior to 19%, both of them being more representative in summer. Biomass burning sources represented approximately 1% of the total inputs to the organic aerosol for the most part of the year, excepting during the spring, when it contributed to 10%. Petroleum products and plasticizers presented higher contributions (up to 19%) during the winter months. Secondary constituents resulting from oxidation during transport varied from 14% to 37% of the apportioned organic mass. The fraction derived from soil resuspension accounted for 2-16%.

  7. Aerosol detection methods in lidar-based atmospheric profiling

    NASA Astrophysics Data System (ADS)

    Elbakary, Mohamed I.; Iftekharuddin, Khan M.; De Young, Russell; Afrifa, Kwasi

    2016-09-01

    A compact light detection and ranging (LiDAR) system provides aerosols profile measurements by identifying the aerosol scattering ratio as function of the altitude. The aerosol scattering ratios are used to obtain multiple aerosol intensive ratio parameters known as backscatter color ratio, depolarization ratio and lidar ratio. The aerosol ratio parameters are known to vary with aerosol type, size, and shape. Different methods in the literature are employed for detection and classification of aerosol from the measurements. In this paper, a comprehensive review for aerosol detection methods is presented. In addition, results of implemented methods of quantifying aerosols in the atmosphere on real data are compared and presented showing how the backscatter color, depolarization and lidar ratios vary with presence of aerosols in the atmosphere.

  8. Atmospheric aerosols from Mauna Loa Observatory, Hawaii

    SciTech Connect

    Zoller, W.H.; Holmes, J.L. )

    1993-01-01

    Atmospheric aerosols have been collected for chemical analysis at the Mauna Loa Observatory in Hawaii since 1979. The samples were collected in two wind quadrants, a clean [open quotes]down-slope[close quotes] quadrant and a more contaminated [open quotes]up-slope[close quotes] quadrant. Some of the findings of this work have been the identification of Asian dust traveling to the Hawaiian Islands every spring of the year, and this dust dominates the yearly record because it is very intense and contains predominantly crustal dust along with pollutants from the Asian mainland, such as coal combustion in China. Additional interpretation of the data set of weekly samples has shown the presence of pollutants from both North and South America as well as different areas of Asia that are transported by wind systems to the central Pacific Ocean. By subtracting these episodic transport events, one can look at the oceanic background aerosols that are originating from the ocean and look at the occurrence of the natural aerosol generating systems in the oceanic region that are related to climatic change. One of the important groups of elements are the sulfur and halogen families and the naturally occurring volatile elements (selenium, arsenic, antimony, etc.) that are produced by biogenic activity in the world's oceans and affect the chemistry of the atmosphere, particularly clouds in remote marine areas. Investigations such as this work allow one to evaluate the importance of natural versus anthropogenic sources of the volatile elements to the atmosphere, allowing us to have a much better understanding of man's impact on climate. The nuclear analytical techniques are particularly well suited to this type of sample because it consists of aerosols deposited on a clean Teflon or cellulose substrate, which normally offers very little interference with the analysis.

  9. Characterising atmospheric optical turbulence using stereo-SCIDAR

    NASA Astrophysics Data System (ADS)

    Osborn, James; Butterley, Tim; Föhring, Dora; Wilson, Richard

    2015-04-01

    Stereo-SCIDAR (SCIntillation Detection and Ranging) is a development to the well known SCIDAR method for characterisation of the Earth's atmospheric optical turbulence. Here we present some interesting capabilities, comparisons and results from a recent campaign on the 2.5 m Isaac Newton Telescope on La Palma.

  10. Atmospheric Ion-induced Aerosol Nucleation

    NASA Astrophysics Data System (ADS)

    Curtius, J.; Lovejoy, E. R.; Froyd, K. D.

    2006-08-01

    Ion-induced nucleation has been suggested to be a potentially important mechanism for atmospheric aerosol formation. Ions are formed in the background atmosphere by galactic cosmic rays. A possible connection between galactic cosmic rays and cloudiness has been However, the predictions of current atmospheric nucleation models are highly uncertain because the models are usually based on the liquid drop model that estimates cluster thermodynamics based on bulk properties (e.g., liquid drop density and surface tension). Sulfuric acid (H2SO4) and water are assumed to be the most important nucleating agents in the free troposphere. Measurements of the molecular thermodynamics for the growth and evaporation of cluster ions containing H2SO4 and H2O were performed using a temperature-controlled laminar flow reactor coupled to a linear quadrupole mass spectrometer as well as a temperature-controlled ion trap mass spectrometer. The measurements were complemented by quantum chemical calculations of the cluster ion structures. The analysis yielded a complete set of H2SO4 and H2O binding thermodynamics extending from molecular cluster ions to the bulk, based on experimental thermodynamics for the small clusters. The data were incorporated into a kinetic aerosol model to yield quantitative predictions of the rate of ion-induced nucleation for atmospheric conditions. The model predicts that the negative ion-H2SO4-H2O nucleation mechanism is an efficient source of new particles in the middle and upper troposphere.

  11. Atmospheric science: marine aerosols and iodine emissions.

    PubMed

    McFiggans, Gordon

    2005-02-10

    O'Dowd et al. describe the formation of marine aerosols from biogenic iodine and the growth of these aerosols into cloud-condensation nuclei (CCN). Based on chamber and modelling results, the authors suggest that biogenic organic iodine compounds emitted from macroalgae may be responsible for coastal particle bursts and that production of these compounds in the open ocean could increase CCN there too. It has since been shown that coastal particles are more likely to be produced from the photooxidation of molecular iodine. Moreover, I contend that open-ocean particle production and cloud enhancement do not result from emissions of organic iodine at atmospheric levels. For iodine particles to affect cloud properties over the remote ocean, an additional source of iodine is necessary as organic precursors cannot be responsible.

  12. Photochemical aerosols in warm exoplanetary atmospheres

    NASA Astrophysics Data System (ADS)

    Imanaka, Hiroshi; Smith, Mark A.; McKay, Christopher P.; Cruikshank, Dale P.; Marley, Mark S.

    2016-10-01

    Recent transit observations of exoplanets have demonstrated the possibility of a wide prevalence of haze/cloud layers at high altitudes. Hydrocarbon photochemical haze could be the candidate for such haze particles on warm sub-Neptunes, but the lack of evidence for methane poses a puzzle for such hydrocarbon photochemical haze. The CH4/CO ratios in planetary atmospheres vary substantially from their temperature and dynamics. We have conducted a series of laboratory simulations to investigate how atmospheric compositions, specifically CH4/CO ratios, affect the haze production rates and their optical properties. The mass production rates in the H2-CH4-CO gas mixtures are rather insensitive to the CH4/CO ratios larger than at 0.3. Significant formation of solid material is observed in a H2-CO gas mixture even without CH4. The complex refractive indices of the aerosol analogue from the H2-CO gas mixture show strong absorption at the visible/near-IR wavelengths. These experimental facts imply that substantial carbonaceous aerosols may be generated in warm H2-CO-CH4 exoplanetary atmospheres, and that it might be responsible for the observed dark albedos at the visible wavelengths.

  13. Size distribution of ions in atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Krivácsy, Z.; Molnár, Á.

    The aim of this paper is to present data about the concentration and size distribution of ions in atmospheric aerosol under slightly polluted urban conditions in Hungary. Concentration of inorganic cations (ammonium, sodium, potassium, calcium, magnesium), inorganic anions (sulfate, nitrate, chloride, carbonate) and organic acids (oxalic, malonic, succinic, formic and acetic acid) for 8 particle size range between 0.0625 and 16 μm were determined. As was the case for ammonium, sulfate and nitrate, the organic acids were mostly found in the fine particle size range. Potassium and chloride were rather uniformly distributed between fine and coarse particles. Sodium, calcium, magnesium and carbonate were practically observed in the coarse mode. The results obtained for the summer and the winter half-year were also compared. The mass concentrations were recalculated in equivalents, and the ion balance was found to be reasonable in most cases. Measurement of the pH of the aerosol extracts indicates that the aerosol is acidic in the fine mode, but alkaline in the coarse particle size range.

  14. The Organic Aerosols of Titan's Atmosphere

    NASA Technical Reports Server (NTRS)

    Sotin, Christophe; Lawrence, Kenneth; Beauchamp, Patricia M.; Zimmerman, Wayne

    2012-01-01

    One of Titan's many characteristics is the presence of a haze that veils its surface. This haze is composed of heavy organic particles and determining the chemical composition of these particles is a primary objective for future probes that would conduct in situ analysis. Meanwhile, solar occultations provide constraints on the optical characteristics of the haze layer. This paper describes solar occultation observations obtained by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft. These observations strongly constrain the optical characteristics of the haze layer. We detail the different steps involved in the processing of these data and apply them to two occultations that were observed at the South Pole and at the equator in order to investigate the latitudinal dependence of optical properties. The light curves obtained in seven atmospheric windows between 0.933-microns to 5-microns allow us to characterize atmospheric layers from 300 km to the surface. Very good fits of the light curves are obtained using a simple profile of number density of aerosols that is characterized by a scale height. The main difference between the South Pole and the equator is that the value of the scale height increases with altitude at the South Pole whereas it decreases at the equator. The vertically integrated amount of aerosols is similar at the two locations. The curve describing the cross-section versus wavelength is identical at the two locations suggesting that the aerosols have similar characteristics. Finally, we find that the two-way vertical transmission at 5-microns is as large as 80% at both locations.

  15. Vapor scavenging by atmospheric aerosol particles

    SciTech Connect

    Andrews, E.

    1996-05-01

    Particle growth due to vapor scavenging was studied using both experimental and computational techniques. Vapor scavenging by particles is an important physical process in the atmosphere because it can result in changes to particle properties (e.g., size, shape, composition, and activity) and, thus, influence atmospheric phenomena in which particles play a role, such as cloud formation and long range transport. The influence of organic vapor on the evolution of a particle mass size distribution was investigated using a modified version of MAEROS (a multicomponent aerosol dynamics code). The modeling study attempted to identify the sources of organic aerosol observed by Novakov and Penner (1993) in a field study in Puerto Rico. Experimentally, vapor scavenging and particle growth were investigated using two techniques. The influence of the presence of organic vapor on the particle`s hydroscopicity was investigated using an electrodynamic balance. The charge on a particle was investigated theoretically and experimentally. A prototype apparatus--the refractive index thermal diffusion chamber (RITDC)--was developed to study multiple particles in the same environment at the same time.

  16. Coarse atmospheric aerosol: size distributions of trace elements

    NASA Astrophysics Data System (ADS)

    Eleftheriadis, K.; Colbeck, I.

    A sampler, employing nine single stage impactors placed in parallel within a portable wind tunnel, has been used to determine the metal content of coarse atmospheric aerosol. The wind tunnel maintains a constant flow environment for the collectors housed inside it, so that representative sampling conditions are achieved compared to the varied ambient wind conditions. At a flow rate of 8 m s -1 the 50% cut-off diameters of the impactors ranged from 7.8 to 38.8 μm. Measurements were conducted at a rural and urban site near Colchester in south east England. The samplers were analysed by PIXE for P, K, Ca, Fe, Ti, Mn, Cu, V, Co, Cr, Br, Zn, Ni, Sc and Pb. It is found that the sampler can be employed to quantitatively characterise the elemental mass size distribution for aerosol larger than 10 μm. The results indicate that a small fraction of the above earth and trace elements' metal mass is present in particles greater than 10 μm. This fraction for earth metals (Ca, K, Ti) is comparatively greater in the rural site than the urban site, while for trace metals (Mn, V, Cu, Cr) this fraction constitutes a more significant part of the coarse mass at the urban site. Trace element concentrations were of a similar order of magnitude to earlier literature reports. Although the number of measurements was limited it can be concluded that the size distributions obtained were characteristic of an unpolluted area.

  17. The effect of aerosols on the earth-atmosphere albedo

    NASA Technical Reports Server (NTRS)

    Herman, B. M.; Browning, S. R.

    1975-01-01

    The paper presents calculations of the change in reflected flux by the earth-atmosphere system in response to increases in the atmospheric aerosol loading for a range of complex indices of refraction, solar elevation angle and ground albedo. Results show that, for small values of ground albedo, the reflected solar flux may either increase or decrease with increasing aerosol loadings, depending upon the complex part of the index of refraction of the aerosols. For high ground albedos, an increase in aerosol levels always results in a decrease of reflected flux (i.e., a warming of the earth-atmosphere system).

  18. Overview of atmospheric aerosol studies in Malaysia: Known and unknown

    NASA Astrophysics Data System (ADS)

    Kanniah, Kasturi Devi; Kaskaoutis, Dimitris G.; San Lim, Hwee; Latif, Mohd Talib; Kamarul Zaman, Nurul Amalin Fatihah; Liew, Juneng

    2016-12-01

    Atmospheric aerosols particularly those originated from anthropogenic sources can affect human health, air quality and the regional climate system of Southeast Asia (SEA). Population growth, and rapid urbanization associated with economic development in the SEA countries including Malaysia have resulted in high aerosol concentrations. Moreover, transboundary smoke plumes add more aerosols to the atmosphere in Malaysia. Nevertheless, the aerosol monitoring networks and/or field studies and research campaigns investigating the various aerosol properties are not so widespread over Malaysia. In the present work, we summarize and discuss the results of previous studies that investigated the aerosol properties over Malaysia by means of various instrumentation and techniques, focusing on the use of remote sensing data to examine atmospheric aerosols. Furthermore, we identify gaps in this research field and recommend further studies to bridge these knowledge gaps. More specifically gaps are identified in (i) monitoring aerosol loading and composition over urban areas, (ii) examining the influence of dust, (iii) assessing radiative effects of aerosols, (iv) measuring and modelling fine particles and (v) quantifying the contribution of long range transport of aerosols. Such studies are crucial for understanding the optical, physical and chemical properties of aerosols and their spatio-temporal characteristics over the region, which are useful for modelling and prediction of aerosols' effects on air quality and climate system.

  19. A naming convention for atmospheric organic aerosol

    NASA Astrophysics Data System (ADS)

    Murphy, B. N.; Donahue, N. M.; Robinson, A. L.; Pandis, S. N.

    2014-06-01

    While the field of atmospheric organic aerosol scientific research has experienced thorough and insightful progress over the last half century, this progress has been accompanied by the evolution of a communicative and detailed yet, at times, complex and inconsistent language. The menagerie of detailed classification that now exists to describe organic compounds in our atmosphere reflects the wealth of observational techniques now at our disposal as well as the rich information provided by state-of-the-science instrumentation. However, the nomenclature in place to communicate these scientific gains is growing disjointed to the point that effective communication within the scientific community and to the public may be sacrificed. We propose standardizing a naming convention for organic aerosol classification that is relevant to laboratory studies, ambient observations, atmospheric models, and various stakeholders for air-quality problems. Because a critical aspect of this effort is to directly translate the essence of complex physico-chemical phenomena to a much broader, policy-oriented audience, we recommend a framework that maximizes comprehension among scientists and non-scientists alike. For example, to classify volatility, it relies on straightforward alphabetic terms (e.g., semivolatile, SV; intermediate volatility, IV; etc.) rather than possibly ambiguous numeric indices. This framework classifies organic material as primary or secondary pollutants and distinguishes among fundamental features important for science and policy questions including emission source, chemical phase, and volatility. Also useful is the addition of an alphabetic suffix identifying the volatility of the organic material or its precursor for when emission occurred. With this framework, we hope to introduce into the community a consistent connection between common notation for the general public and detailed nomenclature for highly specialized discussion. In so doing, we try to maintain

  20. The atmospheric aerosol-forming potential of whole gasoline vapor

    SciTech Connect

    Odum, J.R.; Jungkamp, T.P.W.; Griffin, R.J.

    1997-04-04

    A series of sunlight-irradiated, smog-chamber experiments confirmed that the atmosphere organic aerosol formation potential of whole gasoline vapor can be accounted for solely in terms of the aromatic fraction of the fuel. The total amount of secondary organic aerosol produced from the atmospheric oxidation of whole gasoline vapor can be represented as the sum of the contributions of the individual aromatic molecular constituents of the fuel. The urban atmospheric, anthropogenic hydrocarbon profile is approximated well by evaporated whole gasoline, and thus these results suggest that it is possible to model atmospheric secondary organic aerosol formation. 23 refs., 3 figs., 2 tabs.

  1. A Global Data Assimilation System for Atmospheric Aerosol

    NASA Technical Reports Server (NTRS)

    daSilva, Arlindo

    1999-01-01

    We will give an overview of an aerosol data assimilation system which combines advances in remote sensing of atmospheric aerosols, aerosol modeling and data assimilation methodology to produce high spatial and temporal resolution 3D aerosol fields. Initially, the Goddard Aerosol Assimilation System (GAAS) will assimilate TOMS, AVHRR and AERONET observations; later we will include MODIS and MISR. This data assimilation capability will allows us to integrate complementing aerosol observations from these platforms, enabling the development of an assimilated aerosol climatology as well as a global aerosol forecasting system in support of field campaigns. Furthermore, this system provides an interactive retrieval framework for each aerosol observing satellites, in particular TOMS and AVHRR. The Goddard Aerosol Assimilation System (GAAS) takes advantage of recent advances in constituent data assimilation at DAO, including flow dependent parameterizations of error covariances and the proper consideration of model bias. For its prognostic transport model, GAAS will utilize the Goddard Ozone, Chemistry, Aerosol, Radiation and Transport (GOCART) model developed at NASA/GSFC Codes 916 and 910.3. GOCART includes the Lin-Rood flux-form, semi-Langrangian transport model with parameterized aerosol chemistry and physical processes for absorbing (dust and black carbon) and non-absorbing aerosols (sulfate and organic carbon). Observations and model fields are combined using a constituent version of DAO's Physical-space Statistical Analysis System (PSAS), including its adaptive quality control system. In this talk we describe the main components of this assimilation system and present preliminary results obtained by assimilating TOMS data.

  2. Statistical characteristics of atmospheric aerosol as determined from AERONET measurements

    NASA Astrophysics Data System (ADS)

    Yoon, Jongmin; Kokhanovsky, Alexander

    2015-04-01

    Seasonal means and standard deviations of column-integrated aerosol optical properties (e.g. spectral aerosol optical thickness (AOT), single scattering albedo, phase function, Ångström exponent, volume particle size distribution, complex refractive index, absorbing aerosol optical thickness) from several Aerosol Robotic Network (AERONET) sites located in typical aerosol source and background regions are investigated (Holben et al., 1998). The AERONET program is an inclusive network of ground-based sun-photometers that measure atmospheric aerosol optical properties (http://aeronet.gsfc.nasa.gov/). The results can be used for improving the accuracy of satellite-retrieved AOT, assessments of the global aerosol models, studies of atmospheric pollution and aerosol radiative forcing on climate. We have paid a special attention to several AERONET sites that are Mexico_City (Mexico), Alta_Floresta (Brazil), Avignon (France), Solar_Village (Saudi Arabia), and Midway_Island (Pacific) representative for industrial/urban, biomass burning, rural, desert dust and oceanic aerosols, respectively. We have found that the optical and microphysical aerosol properties are highly dependent on the local aerosol emission sources and seasonal meteorological conditions.

  3. Trace Element Chemistry in Urban Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Farhana, B.; Husain, L.

    2006-12-01

    Unlike in the United States, the concentration of trace elements in urban air is still high enough in South Asian cities to study the impact of trace elements on climate and human health. Hence, continuous sampling of PM2.5 (particulate matter of <2.5 μm aerodynamic diameter)was carried out using low volume sampler in winter (2005-2006) in Lahore, the second largest city of Pakistan, which is highly impacted by urban and agricultural emissions and has remained unexplored in terms of atmospheric chemistry. Aerosols collected on this campaign are likely to carry the signatures of emissions from Afghanistan, North and Central Pakistan, North India in addition to the local pollution sources. During sampling from December 2005 to January 2006, it was possible to collect several samples during brief fog episodes. Samples were analyzed for 25 elements (Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Sr, Mo, Ag, Cd, Sn, Sb, Ba, Tl and Pb) using inductively coupled plasma mass spectrometry. High pollutant concentrations were observed throughout the study, for instance, Cr concentrations up to 1.4 μgm-3, As, 135 ngm-3, Cd, 93 ngm-3, Sn, 988 ngm-3 and Sb, 157 ngm-3. Pb and Zn concentrations respectively up to 12 and 48 μgm-3 were observed. Calculation of enrichment factor and crustal correction illustrate the attribution of Cr, Co, Ni, Zn, As, Se, Mo, Ag Cd, Sn, Sb, Tl and Pb to non-crustal sources. Air parcel back trajectories, interelemental relationships and meteorological observations have been used to explain the sources and the impacts of fog chemistry and mixing heights on atmospheric processing of trace elements in PM2.5. Atmospheric stagnation appeared to be one of factors causing episodic high concentrations. Crustal correction and interelemental relationships apparently suggest the emissions from coal and oil combustion, industrial processes, building construction sites and biomass burning as the prime role players in the atmospheric pollution in

  4. Identification and characterisation of local aerosol sources using high temporal resolution measurements.

    PubMed

    Contini, D; Donateo, A; Cesari, D; Belosi, F; Francioso, S

    2010-09-01

    Aerosol and gaseous pollution measurements were carried out at an urban background site in the south of Italy located near an industrial complex. Collection of 24 h samples of PM10 and PM2.5 and successive chemical quantification of metals were performed. Data were compared with measurements taken at a suburban background site, located at 25 km distance. The comparison showed the presence of an industrial contribution with a well defined chemical emission profile, similar, in terms of metals content, to urban emissions. As this made difficult the quantitative characterisation of the contribution of the two sources to atmospheric PM, a statistical method based on the treatment of data arising from high temporal resolution measurements was developed. Data were taken with a micrometeorological station based on an integrating nephelometer (Mie pDR-1200) for optical detection of PM2.5 concentration, with successive evaluation of vertical turbulent fluxes using the eddy-correlation method. Results show that the contribution from the two sources (urban emissions and industrial releases) have a very different behaviour, with the industrial contribution being present at high wind velocity with short concentration peaks (average duration 4 min) associated to strong positive and negative vertical fluxes. The estimated contribution to PM2.5 is 2.3% over long-term averages. The urban emissions are mainly present at low wind velocity, with longer concentration peaks in the morning and late evening hours, generally associated to small positive vertical fluxes. The characterisation of the contribution was performed using deposition velocity V(d) that is on average -3.5 mm s(-1) and has a diurnal pattern, with negligible values during the night and a minimum value of around -9 mm s(-1) late in the afternoon. Results show a correlation between V(d), friction velocity and wind velocity that could be the basis for a parameterisation of V(d) to be used in dispersion codes.

  5. The Role of Anthropogenic Aerosol in Atmospheric Circulation Changes

    NASA Astrophysics Data System (ADS)

    Wilcox, L.; Polvani, L. M.; Highwood, E.

    2015-12-01

    Changes in atmospheric circulation patterns play a dominant role in determining the impacts of a changing climate at the continental scale. Using CMIP5 single forcing experiments from an ensemble of models that provided anthropogenic aerosol only simulations to the archive, we quantify the influence of anthropogenic aerosol on several aspects of the atmospheric circulation, including tropical width, jet position, and jet strength. We show that there is a robust circulation response to anthropogenic aerosol in the mid twentieth century, induced by the large increases in emissions at that time. Although most anthropogenic aerosol is found in the Northern Hemisphere, a response is found in both the Northern and Southern hemispheres. We investigate the extent to which diversity in the temperature and circulation responses to aerosol are related to diversity in aerosol loading and radiative forcing.

  6. Aerosol Forcing of Climate Change and "Anomalous" Atmospheric Absorption

    NASA Technical Reports Server (NTRS)

    Hansen, James E.

    1999-01-01

    The forcings that drive long-term climate change are not known with an accuracy sufficient to define future climate change. Anthropogenic greenhouse gases (GHGs), which are well-measured, cause a strong positive (warming) forcing. But other, poorly measured, anthropogenic forcings, especially changes of atmospheric aerosols, clouds, and land-use patterns, cause a negative forcing that tends to offset greenhouse warming. We will focus on the role of aerosols as a climate forcing mechanism and the contribution that aerosols might make to the so- called "anomalous" atmospheric absorption that has been inferred from some atmospheric measurements.

  7. Aerosol Forcing of Climate Change and Anomalous Atmospheric Absorption

    NASA Technical Reports Server (NTRS)

    Hansen, James E.

    2000-01-01

    The forcings that drive long-term climate change are not known with an accuracy sufficient to define future climate change, Anthropogenic greenhouse gases (GHGs), which are well-measured, cause a strong positive (warming) forcing. But other, poorly measured, anthropogenic forcings, especially changes of atmospheric aerosols, clouds, and land-use patterns, cause a negative forcing that tends to offset greenhouse warming. We will focus on the role of aerosols as a climate forcing mechanism and the contribution that aerosols might make to the so-called "anomalous" atmospheric absorption that has been inferred from some atmospheric measurements.

  8. Laser radar measurements of the aerosol content of the atmosphere

    NASA Technical Reports Server (NTRS)

    Grams, G. W.

    1969-01-01

    A summary of the results of laser radar observations of atmospheric aerosols is presented along with a description of the laser radar system devised during the study and of the data handling techniques utilized for the analysis of the data of the temporal and spatial distribution of atmospheric aerosols. Current research conducted by the group is directed toward the analysis of the frequency spectrum of laser radar echoes to obtain absolute measurements of the dust content of the atmosphere by resolving the molecular and aerosol contributions to the laser radar echoes.

  9. Atmospheric aerosol monitoring at the Pierre Auger Observatory

    SciTech Connect

    Cester, R.; Chiosso, M.; Chirin, J.; Clay, R.; Dawson, B.; Fick, B.; Filipcic, A.; Garcia, B.; Grillo, A.; Horvat, M.; Iarlori, M.; Malek, M.; Matthews, J.; Matthews, J.A.J.; Melo, D.; Meyhandan, R.; Mostafa, M.; Mussa, R.; Prouza, M.; Raefert, B.; Rizi, V.

    2005-07-01

    For a ground based cosmic-ray observatory the atmosphere is an integral part of the detector. Air fluorescence detectors (FDs) are particularly sensitive to the presence of aerosols in the atmosphere. These aerosols, consisting mainly of clouds and dust, can strongly affect the propagation of fluorescence and Cherenkov light from cosmic-ray induced extensive air showers. The Pierre Auger Observatory has a comprehensive program to monitor the aerosols within the atmospheric volume of the detector. In this paper the aerosol parameters that affect FD reconstruction will be discussed. The aerosol monitoring systems that have been deployed at the Pierre Auger Observatory will be briefly described along with some measurements from these systems.

  10. Evidence for Novel Atmospheric Organic Aerosol Measured in a Bornean Rainforest

    NASA Astrophysics Data System (ADS)

    Robinson, N. H.; Hamilton, J. F.; Allan, J. D.; Langford, B.; Oram, D. E.; Chen, Q.; Ward, M. W.; Hewitt, C. N.; Martin, S. T.; Coe, H.; McFiggans, G. B.

    2009-12-01

    The tropics emit a huge amount of volatile organic compounds (VOCs) into the Earth’s atmosphere. The processes by which these gases are oxidised to form secondary organic aerosol (SOA) are currently not well understood or quantified. Intensive field measurements were carried out as part of the Oxidant and Particle Photochemical Processes (OP3) and the Aerosol Coupling in the Earth System (ACES) projects around pristine rainforest in Malaysian Borneo. This is the first campaign of its type in a South East Asian rainforest. We present detailed organic aerosol composition measurements made using an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) at Bukit Atur, a Global Atmosphere Watch site located in the Danum Valley Conservation Area. This is a state-of-the-art field deployable instrument that can provide real time composition, mass loading and aerodynamic particle sizing information. In addition, the mass spectral resolution is sufficient to perform an analysis of the elemental composition of the organic species present. Off line analysis of filter samples was performed using comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (GCxGC/ToFMS). This technique provide a more detailed chemical characterisation of the SOA, allowing direct links back to gas phase precursors. The ground site data are compared with Aerodyne Compact Time of Flight Aerosol Mass Spectrometer (C-ToF-AMS) measurements made on the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft. Airborne measurements were made above pristine rainforest surrounding the Danum Valley site, as well as nearby oil palm agricultural sites and palm oil rendering plants. Proton Transfer Reaction Mass Spectrometry (PTRMS) measurements of VOCs were made at the ground site and from the FAAM aircraft. Novel organic aerosol was measured by both AMSs, and identified by GCxGC/ToFMS analysis. The aerosol component was

  11. Remote sensing of aerosol in the terrestrial atmosphere from space: "AEROSOL-UA" mission

    NASA Astrophysics Data System (ADS)

    Yatskiv, Yaroslav; Milinevsky, Gennadi; Degtyarev, Alexander

    2016-07-01

    The distribution and properties of atmospheric aerosols on a global scale are not well known in terms of determination of their effects on climate. This mostly is due to extreme variability of aerosol concentrations, properties, sources, and types. Aerosol climate impact is comparable to the effect of greenhouse gases, but its influence is more difficult to measure, especially with respect to aerosol microphysical properties and the evaluation of anthropogenic aerosol effect. There are many satellite missions studying aerosol distribution in the terrestrial atmosphere, such as MISR/Terra, OMI/Aura, AVHHR, MODIS/Terra and Aqua, CALIOP/CALIPSO. To improve the quality of data and climate models, and to reduce aerosol climate forcing uncertainties, several new missions are planned. The gap in orbital instruments for studying aerosol microphysics has arisen after the Glory mission failed during launch in 2011. In this review paper, we describe several planned aerosol space missions, including the Ukrainian project AEROSOL-UA that will obtain the data using a multi-channel scanning polarimeter and wide-angle polarimetric camera. The mission is designed for remote sensing of the aerosol microphysics and cloud properties on a global scale.

  12. The Regional Environmental Impacts of Atmospheric Aerosols over Egypt

    NASA Astrophysics Data System (ADS)

    Zakey, Ashraf; Ibrahim, Alaa

    2015-04-01

    Identifying the origin (natural versus anthropogenic) and the dynamics of aerosols over Egypt at varying temporal and spatial scales provide valuable knowledge on the regional climate impacts of aerosols and their ultimate connections to the Earth's regional climate system at the MENA region. At regional scale, Egypt is exposed to air pollution with levels exceeding typical air-quality standards. This is particularly true for the Nile Delta region, being at the crossroads of different aerosol species originating from local urban-industrial and biomass-burning activities, regional dust sources, and European pollution from the north. The Environmental Climate Model (EnvClimA) is used to investigate both of the biogenic and anthropogenic aerosols over Egypt. The dominant natural aerosols over Egypt are due to the sand and dust storms, which frequently occur during the transitional seasons (spring and autumn). In winter, the maximum frequency reaches 2 to 3 per day in the north, which decreases gradually southward with a frequency of 0.5-1 per day. Monitoring one of the most basic aerosol parameters, the aerosol optical depth (AOD), is a main experimental and modeling task in aerosol studies. We used the aerosol optical depth to quantify the amount and variability of aerosol loading in the atmospheric column over a certain areas. The aerosols optical depth from the model is higher in spring season due to the impacts of dust activity over Egypt as results of the westerly wind, which carries more dust particles from the Libyan Desert. The model result shows that the mass load of fine aerosols has a longer life-time than the coarse aerosols. In autumn season, the modelled aerosol optical depth tends to increase due to the biomass burning in the delta of Egypt. Natural aerosol from the model tends to scatter the solar radiation while most of the anthropogenic aerosols tend to absorb the longwave solar radiation. The overall results indicate that the AOD is lowest in winter

  13. Atmospheric aerosol monitoring by an elastic Scheimpflug lidar system.

    PubMed

    Mei, Liang; Brydegaard, Mikkel

    2015-11-30

    This work demonstrates a new approach - Scheimpflug lidar - for atmospheric aerosol monitoring. The atmospheric backscattering echo of a high-power continuous-wave laser diode is received by a Newtonian telescope and recorded by a tilted imaging sensor satisfying the Scheimpflug condition. The principles as well as the lidar equation are discussed in details. A Scheimpflug lidar system operating at around 808 nm is developed and employed for continuous atmospheric aerosol monitoring at daytime. Localized emission, atmospheric variation, as well as the changes of cloud height are observed from the recorded lidar signals. The extinction coefficient is retrieved according to the slope method for a homogeneous atmosphere. This work opens up new possibilities of using a compact and robust Scheimpflug lidar system for atmospheric aerosol remote sensing.

  14. Subarctic atmospheric aerosol composition: 1. Ambient aerosol characterization

    SciTech Connect

    Friedman, Beth; Herich, Hanna; Kammermann, Lukas; Gross, Deborah S.; Ameth, Almut; Holst, Thomas; Lohmann, U.; Cziczo, Daniel J.

    2009-07-10

    Sub-Arctic aerosol was sampled during July 2007 at the Abisko Research Station Stordalen field site operated by the Royal Swedish Academy of Sciences. Located in northern Sweden at 68º latitude and 385 meters above sea level (msl), this site is classified as a semi-continuous permafrost mire. Number density, size distribution, cloud condensation nucleus properties, and chemical composition of the ambient aerosol were determined. Backtrajectories showed that three distinct airmasses were present over Stordalen during the sampling period. Aerosol properties changed and correlated with airmass origin to the south, northeast, or west. We observe that Arctic aerosol is not compositionally unlike that found in the free troposphere at mid-latitudes. Internal mixtures of sulfates and organics, many on insoluble biomass burning and/or elemental carbon cores, dominate the number density of particles from ~200 to 2000 nm aerodynamic diameter. Mineral dust which had taken up gas phase species was observed in all airmasses. Sea salt, and the extent to which it had lost volatile components, was the aerosol type that most varied with airmass.

  15. Aerosol retrieval in hazy atmosphere by using polarization and radiance

    NASA Astrophysics Data System (ADS)

    Mukai, S.; Sano, I.; Nakata, M.

    2014-12-01

    Aerosol retrieval is achieved by radiative transfer simulation in the Earth atmosphere model. This work intends to propose an algorithm for multiple light scattering simulations in the hazy polarized radiation field. We have already solved the scalar radiative transfer problem in the case of haze episodes with dense concentrations of atmospheric aerosols by the method of successive order of scattering, which is named scalar-MSOS. The term "scalar" indicates radiance alone in the treatment of radiative transfer problem against "vector" involving polarized radiation field. The satellite polarimetric sensor POLDER-1, 2, 3 has shown that the spectro-photopolarimetry of terrestrial atmosphere is very useful for observation of the Earth, especially for aerosols. JAXA has been developing the new Earth observing system, GCOM satellite. GCOM-C will board the polarimetric sensor SGLI in 2017. It is highly likely that large-scale aerosol episodes will continue to occur, because the air pollution becomes to be severe due to both the increasing emissions of the anthropogenic aerosols and the complicated behavior of natural aerosols. Then many potential applications for the kind of radiation simulation by MSOS considering the polarization information denoted by Stokes parameters (I, Q, U, V), named vector-MSOS, are desired. It is shown here that dense aerosol episodes can be well simulated by a semi-infinite radiation model composed of the proposed aerosol models. In addition our vector-MSOS is examined in practice by combination use of PARASOL/POLDER, GOSAT/CAI and Aqua/MODIS data.

  16. Present role of PIXE in atmospheric aerosol research

    NASA Astrophysics Data System (ADS)

    Maenhaut, Willy

    2015-11-01

    In the 1980s and 1990s nearly half of the elemental analyses of atmospheric aerosol samples were performed by PIXE. Since then, other techniques for elemental analysis became available and there has been a steady increase in studies on organic aerosol constituents and other aspects of aerosols, especially in the areas of nucleation (new particle formation), optical properties, and the role of aerosol particles in cloud formation and properties. First, a brief overview and discussion is given of the developments and trends in atmospheric aerosol analysis and research of the past three decades. Subsequently, it is indicated that there is still invaluable work to be done by PIXE in atmospheric aerosol research, especially if one teams up with other aerosol researchers and performs complementary measurements, e.g., on small aerosol samples that are taken with high-time resolution. Fine examples of such research are the work done by the Lund group in the CARIBIC aircraft studies and the analysis of circular streaker samples by the Florence PIXE group. These and other examples are presented and other possibilities of PIXE are indicated.

  17. Atmospheric aerosol variability and properties in lowermost tropical free troposphere

    NASA Astrophysics Data System (ADS)

    Krejci, Radovan; Hamburger, Thomas; Ström, Johan; Tunved, Peter; Schmeissner, Tina; Matisans, Modris; Calderon, Silvia; Hoffman, Pedro

    2013-05-01

    The long-term measurements of aerosol number and size distributions in tropical free troposphere (FT) were carried out from 2007 until 2009. The measurements took place at the high altitude Atmospheric Research Station Pico Espejo located on top of the Sierra Nevada mountain ridge at 4765 m a.s.l. nearby the city of Mérida, Venezuela. Analysis of aerosol number concentration, size distribution and light absorbing aerosol focuses mainly on possible links to the atmospheric general circulation in the tropics and seasonality driven changes in biomass burning activity. Repeatable annual and diurnal cycles of the particle number concentration were observed.

  18. Airborne High Spectral Resolution Lidar Measurements of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Ferrare, R.; Hostetler, C.; Hair, J.; Cook, A.; Harper, D.; Kleinman, L.; Clarke, A.; Russell, P.; Redemann, J.; Livingston, J.; Szykman, J.; Al-Saadi, J.

    2007-05-01

    NASA Langley Research Center (LaRC) recently developed an airborne High Spectral Resolution Lidar (HSRL) to measure aerosol distributions and optical properties. The HSRL technique takes advantage of the spectral distribution of the lidar return signal to discriminate aerosol and molecular signals and thereby measure aerosol extinction and backscatter independently. The LaRC instrument employs the HSRL technique to measure aerosol backscatter and extinction profiles at 532 nm and the standard backscatter lidar technique to measure aerosol backscatter profiles at 1064 nm. Depolarization profiles are measured at both wavelengths. Since March 2006, the airborne HSRL has acquired over 215 flight hours of data deployed on the NASA King Air B200 aircraft during several field experiments. Most of the flights were conducted during two major field experiments. The first major experiment was the joint Megacity Initiative: Local and Global Research Observations (MILAGRO) /Megacity Aerosol Experiment in Mexico City (MAX-MEX)/Intercontinental Chemical Transport Experiment-B (INTEX B) experiment that was conducted during March 2006 to investigate the evolution and transport of pollution from Mexico City. The second major experiment was the Texas Air Quality Study (TEXAQS)/Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) that was conducted during August and September 2006 to investigate climate and air quality in the Houston/Gulf of Mexico region. Several flights were also conducted to help validate the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) lidar on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite (CALIPSO) satellite. In February 2007, several flights were carried out as part of an Environmental Protection Agency (EPA) experiment to assess air quality in central California. Airborne HSRL data acquired during these missions were used to quantify aerosol extinction and optical thickness contributed by various aerosol types

  19. Hygroscopic and chemical characterisation of Po Valley aerosol

    NASA Astrophysics Data System (ADS)

    Bialek, J.; Dall'Osto, M.; Vaattovaara, P.; Ovadnevaite, J.; Decesari, S.; Laaksonen, A.; O'Dowd, C.

    2013-02-01

    Continental summer-time aerosol in the Italian Po Valley was characterized in terms of hygroscopic properties and the influence of chemical composition therein. The campaign-average minima in hygroscopic growth factors (HGFs) occurred just before and during sunrise from 03:00-06:00, but more generally, the whole night shows very low hygroscopicity, particularly in the smaller particle sizes. The average HGFs increased from 1.18 for the smallest sized particles (35 nm) to 1.38 for the largest sizes (165 nm) for the lowest HGF period while during the day, the HGF gradually increased to achieve maximum values in the early afternoon hours from 12:00-15:00, reaching 1.32 for 35 nm particles and 1.46 for 165 nm particles. Two contrasting case scenarios were encountered during the measurement period: Case 1 was associated with westerly air flow moving at a moderate pace and Case 2 was associated with more stagnant, slower moving air from the north-easterly sector. Case 1 exhibited low diurnal temporal patterns and was associated with moderate non-refractory aerosol mass concentrations (for 50% size cut at 1 μm) of the order of 4.5 μg m-3. For Case 1, organics contributed typically to 50% of the mass. Case 2 was characterized by > 9.5 μg m-3 total mass (< 1 μm) in the early morning hours (04:00), decreasing to ∼ 3 μg m-3 by late morning (10:00) and exhibited strong diurnal changes in chemical composition, particularly in nitrate mass but also in total organic mass concentrations. Organic growth factors (OGFs) exhibited a minimum around 15:00, 1-2 h after the peak in HGF. Particles sized 165 nm exhibited moderate diurnal variability in HGF, ranging from 80% at night to 95% of "more hygroscopic" growth factors (i.e. GF = 1.35-1.9) around noon. The diurnal changes in HGF progressively became enhanced with decreasing particle size, decreasing from 95% "more hygroscopic" growth factor fraction at noon to 10% fraction at midnight, while the "less hygroscopic" growth

  20. Remote sensing for studying atmospheric aerosols in Malaysia

    NASA Astrophysics Data System (ADS)

    Kanniah, Kasturi D.; Kamarul Zaman, Nurul A. F.

    2015-10-01

    The aerosol system is Southeast Asia is complex and the high concentrations are due to population growth, rapid urbanization and development of SEA countries. Nevertheless, only a few studies have been carried out especially at large spatial extent and on a continuous basis to study atmospheric aerosols in Malaysia. In this review paper we report the use of remote sensing data to study atmospheric aerosols in Malaysia and document gaps and recommend further studies to bridge the gaps. Satellite data have been used to study the spatial and seasonal patterns of aerosol optical depth (AOD) in Malaysia. Satellite data combined with AERONET data were used to delineate different types and sizes of aerosols and to identify the sources of aerosols in Malaysia. Most of the aerosol studies performed in Malaysia was based on station-based PM10 data that have limited spatial coverage. Thus, satellite data have been used to extrapolate and retrieve PM10 data over large areas by correlating remotely sensed AOD with ground-based PM10. Realising the critical role of aerosols on radiative forcing numerous studies have been conducted worldwide to assess the aerosol radiative forcing (ARF). Such studies are yet to be conducted in Malaysia. Although the only source of aerosol data covering large region in Malaysia is remote sensing, satellite observations are limited by cloud cover, orbital gaps of satellite track, etc. In addition, relatively less understanding is achieved on how the atmospheric aerosol interacts with the regional climate system. These gaps can be bridged by conducting more studies using integrated approach of remote sensing, AERONET and ground based measurements.

  1. Aerosol polarization effects on atmospheric correction and aerosol retrievals in ocean color remote sensing.

    PubMed

    Wang, Menghua

    2006-12-10

    The current ocean color data processing system for the Sea-viewing Wide Field-of-View Sensor (SeaWiFS) and the moderate resolution imaging spectroradiometer (MODIS) uses the Rayleigh lookup tables that were generated using the vector radiative transfer theory with inclusion of the polarization effects. The polarization effects, however, are not accounted for in the aerosol lookup tables for the ocean color data processing. I describe a study of the aerosol polarization effects on the atmospheric correction and aerosol retrieval algorithms in the ocean color remote sensing. Using an efficient method for the multiple vector radiative transfer computations, aerosol lookup tables that include polarization effects are generated. Simulations have been carried out to evaluate the aerosol polarization effects on the derived ocean color and aerosol products for all possible solar-sensor geometries and the various aerosol optical properties. Furthermore, the new aerosol lookup tables have been implemented in the SeaWiFS data processing system and extensively tested and evaluated with SeaWiFS regional and global measurements. Results show that in open oceans (maritime environment), the aerosol polarization effects on the ocean color and aerosol products are usually negligible, while there are some noticeable effects on the derived products in the coastal regions with nonmaritime aerosols.

  2. African Dust Aerosols as Atmospheric Ice Nuclei

    NASA Technical Reports Server (NTRS)

    DeMott, Paul J.; Brooks, Sarah D.; Prenni, Anthony J.; Kreidenweis, Sonia M.; Sassen, Kenneth; Poellot, Michael; Rogers, David C.; Baumgardner, Darrel

    2003-01-01

    Measurements of the ice nucleating ability of aerosol particles in air masses over Florida having sources from North Africa support the potential importance of dust aerosols for indirectly affecting cloud properties and climate. The concentrations of ice nuclei within dust layers at particle sizes below 1 pn exceeded 1/cu cm; the highest ever reported with our device at temperatures warmer than homogeneous freezing conditions. These measurements add to previous direct and indirect evidence of the ice nucleation efficiency of desert dust aerosols, but also confirm their contribution to ice nuclei populations at great distances from source regions.

  3. Carbonaceous aerosols influencing atmospheric radiation: Black and organic carbon

    SciTech Connect

    Penner, J.E.

    1994-09-01

    Carbonaceous particles in the atmosphere may both scatter and absorb solar radiation. The fraction associated with the absorbing component is generally referred to as black carbon (BC) and is mainly produced from incomplete combustion processes. The fraction associated with condensed organic compounds is generally referred to as organic carbon (OC) or organic matter and is mainly scattering. Absorption of solar radiation by carbonaceous aerosols may heat the atmosphere, thereby altering the vertical temperature profile, while scattering of solar radiation may lead to a net cooling of the atmosphere/ocean system. Carbonaceous aerosols may also enhance the concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the fine particle (D < 2.5 {mu}m) source rates of both OC and BC. The source rates for anthropogenic organic aerosols may be as large as the source rates for anthropogenic sulfate aerosols, suggesting a similar magnitude of direct forcing of climate. The role of BC in decreasing the amount of reflected solar radiation by OC and sulfates is discussed. The total estimated forcing depends on the source estimates for organic and black carbon aerosols which are highly uncertain. The role of organic aerosols acting as cloud condensation nuclei (CCN) is also described.

  4. Evidence for a High Proportion of Atmospheric Organic Aerosol from Isoprene

    NASA Astrophysics Data System (ADS)

    Robinson, Niall H.; Hamilton, Jacqueline F.; Langford, Ben; Oram, David E.; Barley, Mark H.; Jenkin, Michael E.; Rickard, Andrew R.; Coe, Hugh; McFiggans, Gordon

    2010-05-01

    The tropics emit a huge amount of volatile organic compounds (VOCs) into the Earth's atmosphere. The processes by which these gases are oxidised to form secondary organic aerosol (SOA) are currently not well understood or quantified. Intensive field measurements were carried out as part of the Oxidant and Particle Photochemical Processes (OP3) and the Aerosol Coupling in the Earth System (ACES) projects around pristine rainforest in Malaysian Borneo. This is the first campaign of its type in a South East Asian rainforest. We present detailed organic aerosol composition measurements made using an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) at Bukit Atur, a Global Atmosphere Watch site located in the Danum Valley Conservation Area. This is a state-of-the-art field deployable instrument that can provide real time composition, mass loading and aerodynamic particle sizing information. In addition, the mass spectral resolution is sufficient to perform an analysis of the elemental composition of the organic species present. Off line analysis of filter samples was performed using comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (GCxGC/ToFMS). This technique provides a more detailed chemical characterisation of the SOA, allowing direct links back to gas phase precursors. The ground site data are compared with Aerodyne Compact Time of Flight Aerosol Mass Spectrometer (C-ToF-AMS) measurements made on the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft. Airborne measurements were made above pristine rainforest surrounding the Danum Valley site, as well as nearby oil palm agricultural sites and palm oil rendering plants. Proton Transfer Reaction Mass Spectrometry (PTRMS) measurements of VOCs were made at the ground site and from the FAAM aircraft. Novel organic aerosol was measured by both AMSs, and identified as being isoprenoid in origin by GCxGC/ToFMS analysis

  5. An investigation of aerosol optical properties: Atmospheric implications and influences

    NASA Astrophysics Data System (ADS)

    Penaloza-Murillo, Marcos A.

    An experimental, observational, and theoretical investigation of aerosol optical properties has been made in this work to study their implications and influences on the atmosphere. In the laboratory the scientific and instrumental methodology consisted of three parts, namely, aerosol generation, optical and mass concentration measurements, and computational calculations. In particular the optical properties of ammonium sulfate and caffeine aerosol were derived from measurements made with a transmissometer cell-reciprocal- integrating nephelometer (TCRIN), equipped with a laser beam at 632.8 nm, and by applying a Mie theory computer code The aerosol generators, optical equipment and calibration procedures were reviewed. The aerosol shape and size distribution were studied by means of scanning electron microscopy and the Gumprecht- Sliepcevich/Lipofsky-Green extinction-sedimentation method. In particular the spherical and cylindrical shape were considered. During this investigation, an alternative method for obtaining the optical properties of monodisperse spherical non-absorbing aerosol using a cell-transmissometer, which is based on a linearisation of the Lambert-Beer law, was found. In addition, adapting the TCRIN to electrooptical aerosol studies, the optical properties of a circular-cylindrical aerosol of caffeine were undertaken under the condition of random orientation in relation with the laser beam, and perpendicular orientation to it. A theoretical study was conducted to assess the sensitivity of aerosol to a change of shape under different polarisation modes. The aerosol optical properties, obtained previously in the laboratory, were then used to simulate the direct radiative forcing. The calculations and results were obtained by applying a one- dimensional energy-balance box model. The influence of atmospheric aerosol on the sky brightness due to a total solar eclipse was studied using the photometric and meteorological observations made during the

  6. CHEMICAL ANALYSIS METHODS FOR ATMOSPHERIC AEROSOL COMPONENTS

    EPA Science Inventory

    This chapter surveys the analytical techniques used to determine the concentrations of aerosol mass and its chemical components. The techniques surveyed include mass, major ions (sulfate, nitrate, ammonium), organic carbon, elemental carbon, and trace elements. As reported in...

  7. AVHRR measurements of atmospheric aerosols over oceans

    NASA Astrophysics Data System (ADS)

    Griggs, M.

    1981-11-01

    A large set of AVHRR and ground-truth data was obtained at ten sites around the globe to investigate the possible global variability of the radiance-aerosol content relationship observed previously with LANDSAT data. The aerosol content was inferred from the AVHRR Channel 1 radiance using an algorithm based on previous LANDSAT measurements at San Diego. The data for four sites were analyzed, and showed excellent agreement between the aerosol content measured by the AVHRR and by sunphotometers at San Diego, Sable Island and San Juan, but at Barbados, the AVHRR appeared to overestimate the aerosol content. The reason for the different relationship at the Barbados site was not definitely established, but is most likely related to problems in interpreting the sunphotometer data rather than to a real overestimation by the AVHRR.

  8. Mesoscale Modeling of the Atmosphere and Aerosols

    DTIC Science & Technology

    2000-09-30

    fires, or the dynamical and topographical forcing is small-scale, as in dust storms . A high-resolution COAMPS is needed to simulate the first stages of...context. However, the tightly coupled application is practical only for dynamically driven aerosols (e.g. dust storms ) or for planned (e.g. known...an imbedded aerosol module for COAMPS for use in the design and evaluation of techniques for coupling off-line transport and dispersion models to

  9. In-situ characterisation of aerosol and gases (SO2, HCl, ozone) in Mt Etna volcano plume

    NASA Astrophysics Data System (ADS)

    Roberts, Tjarda; Vignelles, Damien; Giudice, Gaetano; Liuzzo, Marco; Aiuppa, Alessandro; Chartier, Michel; Coute, Benoit; Lurton, Thibaut; Renard, Jean-Baptiste

    2014-05-01

    We present findings from a measurement campaign that deployed a range of in-situ real-time atmospheric measurement techniques to characterise aerosols and gases in Mt Etna plume in October 2013. The LOAC (Light Optical Aerosol Counter) instrument for size-resolved particle measurements was deployed alongside two Multi-Gas instruments (measuring SO2, H2S, HCl, CO2) and an ozone sensor. Measurements were performed at the summit craters (in cloudy- and non-cloudy conditions) and in grounding downwind plume on the volcano flank. These high frequency measurements (acid gases: 1 to 0.1 Hz, aerosol: 0.1 Hz) provide a detailed in-situ dataset for time-resolved plume characterisation and volcano monitoring. The LOAC measurement of sized-resolved aerosol (over a 0.2 to 50 µm particle diameter range) alongside SO2 (10's ppbv to 10's ppmv) provides a valuable dataset for determining the volcanic aerosol volume and surface area to SO2 ratios. These parameters are presently poorly defined but are important for atmospheric models of the reactive halogen chemistry that occurs on volcanic aerosol surfaces to convert volcanic HBr into reactive bromine, including BrO. The LOAC's patented optical design can also provide insights into particle properties. The two Multi-Gas SO2 time-series show good agreement, detecting co-varying plume fluctuations in the downwind plume, which also correlate with the LOAC total aerosol volume time-series. An estimate of HCl/SO2 in Etna emissions was made by Multi-Gas electrochemical sensor, using a novel design to limit absorption/desorption effects and low-noise electronics for improved resolution. The detection of volcanic HCl by electrochemical sensor brings new possibilities for Multi-Gas monitoring of volcanic halogen emissions. Electrochemical sensor response times are not instantaneous, particularly for sticky gases such as HCl (T90 ~min), but also even for "fast" response (T90 ~ 10 to 30 s) sensors such as SO2 and H2S. However, in a volcanic

  10. In situ physical and chemical characterisation of the Eyjafjallajökull aerosol plume in the free troposphere over Italy

    NASA Astrophysics Data System (ADS)

    Sandrini, S.; Giulianelli, L.; Decesari, S.; Fuzzi, S.; Cristofanelli, P.; Marinoni, A.; Bonasoni, P.; Chiari, M.; Calzolai, G.; Canepari, S.; Perrino, C.; Facchini, M. C.

    2014-01-01

    Continuous measurements of physical and chemical properties at the Mt. Cimone (Italy) GAW-WMO (Global Atmosphere Watch, World Meteorological Organization) Global Station (2165 m a.s.l.) have allowed the detection of the volcanic aerosol plume resulting from the Eyjafjallajökull (Iceland) eruption of spring 2010. The event affected the Mt. Cimone site after a transport over a distance of more than 3000 km. Two main transport episodes were detected during the eruption period, showing a volcanic fingerprint discernible against the free tropospheric background conditions typical of the site, the first from April 19 to 21 and the second from 18 to 20 May 2010. This paper reports the modification of aerosol characteristics observed during the two episodes, both characterised by an abrupt increase in fine and, especially, coarse mode particle number. Analysis of major, minor and trace elements by different analytical techniques (ionic chromatography, particle induced X-ray emission-particle induced gamma-ray emission (PIXE-PIGE) and inductively coupled plasma mass spectrometry (ICP-MS)) were performed on aerosols collected by ground-level discrete sampling. The resulting database allows the characterisation of aerosol chemical composition during the volcanic plume transport and in background conditions. During the passage of the volcanic plume, the fine fraction was dominated by sulphates, denoting the secondary origin of this mode, mainly resulting from in-plume oxidation of volcanic SO2. By contrast, the coarse fraction was characterised by increased concentration of numerous elements of crustal origin, such as Fe, Ti, Mn, Ca, Na, and Mg, which enter the composition of silicate minerals. Data analysis of selected elements (Ti, Al, Fe, Mn) allowed the estimation of the volcanic plume's contribution to total PM10, resulting in a local enhancement of up to 9.5 μg m-3, i.e. 40% of total PM10 on 18 May, which was the most intense of the two episodes. These results appear

  11. Formation and growth of photochemical aerosols in Titan's atmosphere

    NASA Astrophysics Data System (ADS)

    Cabane, M.; Chassefiere, E.; Israel, Guy

    1992-04-01

    Recent development in the understanding of the morphology of haze aerosols in Titan's atmosphere, aggregate particles, and their associated optical properties are considered in the flight of a microphysical model of aerosols. Two different phases of the formation process are identified: initial growth of aerosols near the formation altitude by accretion of very small elementary particles; and (2) settling during which particles of about the same size stock together, leading to the formation of aggregates which contain some tens to several hundred monomers. The first phase leads to the formation of nearly spherical 'monomers' (radius approximately equal to 0.05 micrometers). An eulerian microphysical model is used. It is shown that the monomer radius is extremely sensitive to the altitude where aerosols are created. The formation altitude of aerosols is found to lie in the range from 350 to 400 km.

  12. Polarimetric Remote Sensing of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Hasekamp, O. P.; Stap, A.; di Noia, A.; Rietjens, J.; Smit, M.; van Harten, G.; Snik, F.

    2014-12-01

    To reduce the large uncertainty on the aerosol effects on cloud formation and climate, accurate satellite measurements of aerosol optical properties (optical thickness, single scattering albedo, phase function) and microphysical properties (size distribution, refractive index, shape) are essential. Satellite instruments that perform multi-angle photopolarimetric measurements have the capability to provide these aerosol properties with sufficient accuracy. The only satellite instrument that provided a multi-year data set of multi-angle photopolarimetric measurements is the POLDER-3 instrument onboard the PARASOL microsatellite that operated between 2005-2013. PARASOL provides measurements of a ground scene under (up to) 16 viewing geometries in 9 spectral bands (3 for polarization). In order to make full use of the capability of PARASOL measurements of intensity and polarization properties of reflected light at multiple viewing angles and multiple wavelengths, we developed a retrieval algorithm that considers a continuous parameter space for aerosol microphysical properties (size distribution and refractive index) and properly accounts for land or ocean reflection by retrieving land and ocean parameters simultaneously with aerosol properties. Here, we present the key aspects of our PARASOL retrievals (inverse method, forward model, information content, cloud screening, computational aspects) as well as a validation of retrieved aerosol properties with ground-based measurements of the AERONET network. Also, we discuss required improvements for the next generation of polarimetric instruments dedicated to aerosol remote sensing and introduce a new spectropolarimetric instrument named SPEX. We will demonstrate the capabilities of SPEX based on ground based field measurements and characterization measurements in the labatory.

  13. Surfactants in atmospheric aerosols and rainwater around lake ecosystem.

    PubMed

    Razak, Intan Suraya; Latif, Mohd Talib; Jaafar, Shoffian Amin; Khan, Md Firoz; Mushrifah, Idris

    2015-04-01

    This study was conducted to determine the composition of surfactants in atmospheric aerosols and rainwater in the vicinity of Lake Chini, Malaysia. Samples of atmospheric aerosol and rainwater were collected between March and September 2011 using a high volume air sampler (HVAS) and glass bottles equipped with funnel. Colorimetric analysis was undertaken to determine the concentration of anionic surfactants as methylene blue active substances (MBAS) and cationic surfactants as disulphine blue active substances (DBAS). The water-soluble ionic compositions were determined using inductively coupled plasma mass spectrometry for cations (Na, K, Mg and Ca) and ion chromatography equipped with a conductivity detector for anions (F(-), Cl(-), NO3(-), and SO4(2-)) and the Nessler Method was used to obtain the NH4(+) concentrations. The source apportionment of MBAS and DBAS in atmospheric aerosols was identified using a combination of principal component analysis (PCA) and multiple linear regression (MLR). The results revealed that the concentrations of surfactants in atmospheric aerosols and rainwater were dominated by anionic surfactants as MBAS. The concentration of surfactants as MBAS and DBAS was dominated in fine mode compared to coarse mode aerosols. Using PCA/MLR analysis, two major sources of atmospheric surfactants to Lake Chini were identified as soil dust (75 to 93%) and biomass burning (2 to 22%).

  14. Atmospheric DMS and Biogenic Sulfur aerosol measurements in the Arctic

    NASA Astrophysics Data System (ADS)

    Ghahremaninezhadgharelar, R.; Norman, A. L.; Wentworth, G.; Burkart, J.; Leaitch, W. R.; Abbatt, J.; Sharma, S.; Desiree, T. S.

    2014-12-01

    Dimethyl Sulfide (DMS) and its oxidation products were measured on the board of the Canadian Coast Guard Ship (CCGS) Amundsen and above melt ponds in the Arctic during July 2014 in the context of the NETCARE study which seeks to understand the effect of DMS and its oxidation products with respect to aerosol nucleation, as well as its effect on cloud and precipitation properties. The objective of this study is to quantify the role of DMS in aerosol growth and activation in the Arctic atmosphere. Atmospheric DMS samples were collected from different altitudes, from 200 to 9500 feet, aboard the POLAR6 aircraft expedition to determine variations in the DMS concentration and a comparison was made to shipboard DMS measurements and its effects on aerosol size fractions. The chemical and isotopic composition of sulfate aerosol size fractions was studied. Sulfur isotope ratios (34S/32S) offer a way to determine the oceanic DMS contribution to aerosol growth. The results are expected to address the contribution of anthropogenic as well as biogenic sources of aerosols to the growth of the different aerosol size fractions. In addition, aerosol sulfate concentrations were measured at the same time within precipitation and fogs to compare with the characteristics of aerosols in each size fraction with the characteristics of the sulfate in each medium. This measurement is expected to explain the contribution of DMS oxidation in aerosol activation in the Arctic summer. Preliminary results from the measurement campaign for DMS and its oxidation products in air, fog and precipitation will be presented.

  15. Estimation of the efficiency of atmospheric ozone aerosol sink

    NASA Astrophysics Data System (ADS)

    Sirota, Vitaly

    1993-11-01

    The interaction of ozone with oxides occurring in aerosols (Al2O3, ZnO, MgO, TiO2) at temperatures 22 divided by -63.5 degree(s)C was provided. Laboratory experiments have shown that activity of investigated oxides with respect to ozone grows under irradiation of their surface. To calculate correctly atmospheric ozone aerosol sink one must take account of both heterogeneous processes proceeding without action of light and photocatalytic ones.

  16. Radiation Transfer Model for Aerosol Events in the Earth Atmosphere

    NASA Astrophysics Data System (ADS)

    Mukai, Sonoyo; Yokomae, Takuma; Nakata, Makiko; Sano, Itaru

    Recently large scale-forest fire, which damages the Earth environment as biomass burning and emission of carbonaceous particles, frequently occurs due to the unstable climate and/or global warming tendency. It is also known that the heavy soil dust is transported from the China continent to Japan on westerly winds, especially in spring. Furthermore the increasing emis-sions of anthropogenic particles associated with continuing economic growth scatter serious air pollutants. Thus atmospheric aerosols, especially in Asia, are very complex and heavy loading, which is called aerosol event. In the case of aerosol events, it is rather difficult to do the sun/sky photometry from the ground, however satellite observation is an effective for aerosol monitoring. Here the detection algorithms from space for such aerosol events as dust storm or biomass burn-ing are dealt with multispectral satellite data as ADEOS-2/GLI, Terra/Aqua/MODIS and/or GOSAT/CAI first. And then aerosol retrieval algorithms are examined based on new radiation transfer code for semi-infinite atmosphere model. The derived space-based results are validated with ground-based measurements and/or model simulations. Namely the space-or surface-based measurements, multiple scattering calculations and model simulations are synthesized together for aerosol retrieval in this work.

  17. The colors of biomass burning aerosols in the atmosphere

    PubMed Central

    Liu, Chao; Chung, Chul Eddy; Zhang, Feng; Yin, Yan

    2016-01-01

    Biomass burning aerosols mainly consist of black carbon (BC) and organic aerosols (OAs), and some of OAs are brown carbon (BrC). This study simulates the colors of BrC, BC and their mixture with scattering OAs in the ambient atmosphere by using a combination of light scattering simulations, a two-stream radiative transfer model and a RGB (Red, Green, Blue) color model. We find that both BCs and tar balls (a class of BrC) appear brownish at small particle sizes and blackish at large sizes. This is because the aerosol absorption Ångström exponent (AAE) largely controls the color and larger particles give smaller AAE values. At realistic size distributions, BCs look more blackish than tar balls, but still exhibit some brown color. However, when the absorptance of aerosol layer at green wavelength becomes larger than approximately 0.8, all biomass burning aerosols look blackish. The colors for mixture of purely scattering and absorptive carbonaceous aerosol layers in the atmosphere are also investigated. We suggest that the brownishness of biomass burning aerosols indicates the amount of BC/BrC as well as the ratio of BC to BrC. PMID:27306230

  18. The colors of biomass burning aerosols in the atmosphere

    NASA Astrophysics Data System (ADS)

    Liu, Chao; Chung, Chul Eddy; Zhang, Feng; Yin, Yan

    2016-06-01

    Biomass burning aerosols mainly consist of black carbon (BC) and organic aerosols (OAs), and some of OAs are brown carbon (BrC). This study simulates the colors of BrC, BC and their mixture with scattering OAs in the ambient atmosphere by using a combination of light scattering simulations, a two-stream radiative transfer model and a RGB (Red, Green, Blue) color model. We find that both BCs and tar balls (a class of BrC) appear brownish at small particle sizes and blackish at large sizes. This is because the aerosol absorption Ångström exponent (AAE) largely controls the color and larger particles give smaller AAE values. At realistic size distributions, BCs look more blackish than tar balls, but still exhibit some brown color. However, when the absorptance of aerosol layer at green wavelength becomes larger than approximately 0.8, all biomass burning aerosols look blackish. The colors for mixture of purely scattering and absorptive carbonaceous aerosol layers in the atmosphere are also investigated. We suggest that the brownishness of biomass burning aerosols indicates the amount of BC/BrC as well as the ratio of BC to BrC.

  19. The colors of biomass burning aerosols in the atmosphere.

    PubMed

    Liu, Chao; Chung, Chul Eddy; Zhang, Feng; Yin, Yan

    2016-06-16

    Biomass burning aerosols mainly consist of black carbon (BC) and organic aerosols (OAs), and some of OAs are brown carbon (BrC). This study simulates the colors of BrC, BC and their mixture with scattering OAs in the ambient atmosphere by using a combination of light scattering simulations, a two-stream radiative transfer model and a RGB (Red, Green, Blue) color model. We find that both BCs and tar balls (a class of BrC) appear brownish at small particle sizes and blackish at large sizes. This is because the aerosol absorption Ångström exponent (AAE) largely controls the color and larger particles give smaller AAE values. At realistic size distributions, BCs look more blackish than tar balls, but still exhibit some brown color. However, when the absorptance of aerosol layer at green wavelength becomes larger than approximately 0.8, all biomass burning aerosols look blackish. The colors for mixture of purely scattering and absorptive carbonaceous aerosol layers in the atmosphere are also investigated. We suggest that the brownishness of biomass burning aerosols indicates the amount of BC/BrC as well as the ratio of BC to BrC.

  20. Study of atmospheric aerosols and mixing layer by LIDAR.

    PubMed

    Angelini, Federico; Barnaba, Francesca; Landi, Tony Christian; Caporaso, Luca; Gobbi, Gian Paolo

    2009-12-01

    The LIDAR (laser radar) is an active remote sensing technique, which allows for the altitude-resolved observation of several atmospheric constituents. A typical application is the measurement of the vertically resolved aerosol optical properties. By using aerosol particles as a marker, continuous determination of the mixing layer height (MLH) can also be obtained by LIDAR. Some examples of aerosol extinction coefficient profiles and MLH extracted from a 1-year LIDAR data set collected in Milan (Italy) are discussed and validated against in situ data (from a balloon-borne optical particle counter). Finally a comparison of the observation-based MLH with relevant numerical simulations (mesoscale model MM5) is provided.

  1. Contact ice nucleation by submicron atmospheric aerosols

    NASA Technical Reports Server (NTRS)

    Deshler, T.

    1982-01-01

    An apparatus designed to measure the concentrations of submicron contact ice nuclei is described. Here, natural forces transfer nuclei to supercooled sample drops suspended in an aerosol stream. Experimental measurements of the scavenging rate of the sample drops for several humidities and aerosol sizes are found to be in agreement with theory to within a factor of two. This fact, together with the statistical tests showing a difference between the data and control samples, is seen as indicating that a reliable measurement of the concentrations of submicron contact ice nuclei has been effected. A figure is included showing the ice nucleus concentrations as a function of temperature and assumed aerosol radius. For a 0.01 micron radius, the average is 1/liter at -15 C and 3/liter at -18 C. It is noted that the measurements are in fair agreement with ice crystal concentrations in stable winter clouds measured over Elk Mountain, WY (Vali et al., 1982).

  2. Molecular composition of atmospheric aerosols from Halley Bay, Antarctica, using ultra-high resolution mass spectrometry

    NASA Astrophysics Data System (ADS)

    Kourtchev, Ivan; Brough, Neil; Rincon, Angela; Jones, Anna; Kalberer, Markus

    2016-04-01

    Antarctica is one of the few pristine places to study natural processes of atmospheric aerosols and anthropogenic impacts on the clean remote atmosphere. Although stratospheric aerosol in Antarctica has now been explored in some detail because of the ozone depletion phenomenon, tropospheric aerosol particles in Antarctica remain very little studied. The main goal of this work is to identify in detail the organic chemical composition of aerosol from Halley Bay station, which is located on the Brunt Ice Shelf floating on the Weddell Sea in Antarctica. In this study we characterise the molecular composition of aerosols from three seasons (summer, autumn and winter in 2012) using ultra-high resolution mass spectrometry (UHRMS). The technique provides high accuracy and high mass resolving power that allows determining unambiguous number of organic compounds present in complex organic mixtures (Noziere et al., 2015). The molecular composition interpretation was facilitated using visualisation methods (e.g. double bond equivalent, Van Krevelen diagrams, Kendrick mass analysis, and carbon oxidation state), which allowed to identify patterns, such as differences between sampling times and atmospheric processes. The majority of the identified compounds were attributed to nitrogen and sulphur containing species which exhibited very strong seasonal trends. Relatively large fraction (up to 30% of the total number of molecules) of these species contained very low hydrogen to carbon ratios (below 1) indicating that the site is impacted by anthropogenic emissions. Influences of the meteorological parameters and air mass trajectories on the molecular composition are discussed. Nozière et al., The Molecular Identification of Organic Compounds in the Atmosphere: State of the Art and Challenges, Chem. Rev., 115, 3920-3983, 2015.

  3. Mechanism for production of secondary organic aerosols and their representation in atmospheric models. Final report

    SciTech Connect

    Seinfeld, J.H.; Flagan, R.C.

    1999-06-07

    This document contains the following: organic aerosol formation from the oxidation of biogenic hydrocarbons; gas/particle partitioning of semivolatile organic compounds to model inorganic, organic, and ambient smog aerosols; and representation of secondary organic aerosol formation in atmospheric models.

  4. Heterogeneous Uptake of HO2 Radicals onto Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    George, I. J.; Matthews, P. S.; Brooks, B.; Goddard, A.; Whalley, L. K.; Baeza-Romero, M. T.; Heard, D. E.

    2011-12-01

    The hydroxyl (OH) and hydroperoxyl (HO2) radicals, together known as HOx, play a vital role in atmospheric chemistry by controlling the oxidative capacity of the troposphere. The atmospheric lifetime and concentrations of many trace reactive species, such as volatile organic compounds (VOCs), are determined by HOx radical levels. Therefore, the ability to accurately predict atmospheric HOx concentrations from a detailed knowledge of their sources and sinks is a very useful diagnostic tool to assess our current understanding of atmospheric chemistry. Several recent field studies have observed significantly lower concentrations of HO2 radicals than predicted using box models, where HO2 loss onto aerosols was suggested as a possible missing sink [1, 2]. However, the mechanism on HO2 uptake onto aerosols and its impact on ambient HOx levels are currently not well understood. To improve our understanding of this process, we have conducted laboratory experiments to measure HO2 uptake coefficients onto submicron aerosol particles. The FAGE (Fluorescence Assay by Gas Expansion) technique, a highly sensitive laser induced fluorescence based detection method, was used to monitor HO2 uptake kinetics onto aerosol particles in an aerosol flow tube. The application of the FAGE technique allowed for kinetic experiments to be performed under low HO2 concentrations, i.e. [HO2] < 109 molecules cm-3. HO2 radicals were produced by the photolysis of water vapour in the presence of O2 and aerosol particles were produced either by atomizing dilute salt solutions or by homogeneous nucleation. HO2 uptake coefficients (γ) have been measured for single-component solid and aqueous inorganic salt and organic aerosol particles with a wide range of hygroscopicities. HO2 uptake coefficients on solid particles were below the detection limit (γ < 0.001), whereas on aqueous aerosols uptake coefficients were somewhat larger (γ = 0.001 - 0.008). HO2 uptake coefficients were highest on aerosols

  5. Dust in the Sky: Atmospheric Composition. Modeling of Aerosol Optical Thickness

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Ginoux, Paul; Kinne, Stefan; Torres, Omar; Holben, Brent; Duncan, Bryan; Martin, Randall; Logan, Jennifer; Higurashi, Akiko; Nakajima, Teruyuki

    2000-01-01

    Aerosol is any small particle of matter that rests suspended in the atmosphere. Natural sources, such as deserts, create some aerosols; consumption of fossil fuels and industrial activity create other aerosols. All the microscopic aerosol particles add up to a large amount of material floating in the atmosphere. You can see the particles in the haze that floats over polluted cities. Beyond this visible effect, aerosols can actually lower temperatures. They do this by blocking, or scattering, a portion of the sun's energy from reaching the surface. Because of this influence, scientists study the physical properties of atmospheric aerosols. Reliable numerical models for atmospheric aerosols play an important role in research.

  6. Differential aerosolization of algal and cyanobacterial particles in the atmosphere.

    PubMed

    Sharma, Naveen K; Singh, Surendra

    2010-10-01

    Aeroalgal sampling at short height (2.5 m) over natural aquatic and terrestrial algal sources revealed that despite of being similar in size (<1 mm), algal groups vary in their atmospheric abundance. Cyanobacteria were the most abundant, while chlorophytes and bacillariophytes though present, but rare. Statistical analysis (Akaike Information Criterion) showed that climatic factors (temperature, relative humidity, rainfall, wind velocity and sunshine hours) acted in concert, and mainly affected the release and subsequent vertical movement (aerosolization) of algae from natural sources. Variation in aerosolization may affect the atmospheric abundance of algae. These findings have important implication as dispersal limitation may influence the biogeography and biodiversity of microbial algae.

  7. New satellite project Aerosol-UA: Remote sensing of aerosols in the terrestrial atmosphere

    NASA Astrophysics Data System (ADS)

    Milinevsky, G.; Yatskiv, Ya.; Degtyaryov, O.; Syniavskyi, I.; Mishchenko, M.; Rosenbush, V.; Ivanov, Yu.; Makarov, A.; Bovchaliuk, A.; Danylevsky, V.; Sosonkin, M.; Moskalov, S.; Bovchaliuk, V.; Lukenyuk, A.; Shymkiv, A.; Udodov, E.

    2016-06-01

    We discuss the development of the Ukrainian space project Aerosol-UA which has the following three main objectives: (1) to monitor the spatial distribution of key characteristics of terrestrial tropospheric and stratospheric aerosols; (2) to provide a comprehensive observational database enabling accurate quantitative estimates of the aerosol contribution to the energy budget of the climate system; and (3) quantify the contribution of anthropogenic aerosols to climate and ecological processes. The remote sensing concept of the project is based on precise orbital measurements of the intensity and polarization of sunlight scattered by the atmosphere and the surface with a scanning polarimeter accompanied by a wide-angle multispectral imager-polarimeter. Preparations have already been made for the development of the instrument suite for the Aerosol-UA project, in particular, of the multi-channel scanning polarimeter (ScanPol) designed for remote sensing studies of the global distribution of aerosol and cloud properties (such as particle size, morphology, and composition) in the terrestrial atmosphere by polarimetric and spectrophotometric measurements of the scattered sunlight in a wide range of wavelengths and viewing directions from which a scene location is observed. ScanPol is accompanied by multispectral wide-angle imager-polarimeter (MSIP) that serves to collect information on cloud conditions and Earth's surface image. Various components of the polarimeter ScanPol have been prototyped, including the opto-mechanical and electronic assemblies and the scanning mirror controller. Preliminary synthetic data simulations for the retrieval of aerosol parameters over land surfaces have been performed using the Generalized Retrieval of Aerosol and Surface Properties (GRASP) algorithm. Methods for the validation of satellite data using ground-based observations of aerosol properties are also discussed. We assume that designing, building, and launching into orbit a multi

  8. New Satellite Project Aerosol-UA: Remote Sensing of Aerosols in the Terrestrial Atmosphere

    NASA Technical Reports Server (NTRS)

    Milinevsky, G.; Yatskiv, Ya.; Degtyaryov, O.; Syniavskyi, I.; Mishchenko, Michael I.; Rosenbush, V.; Ivanov, Yu.; Makarov, A.; Bovchaliuk, A.; Danylevsky, V.; Sosonkin, M.; Moskalov, S.; Bovchaliuk, V; Lukenyuk, A.; Shymkiv, A.

    2016-01-01

    We discuss the development of the Ukrainian space project Aerosol-UA which has the following three main objectives: (1) to monitor the spatial distribution of key characteristics of terrestrial tropospheric and stratospheric aerosols; (2) to provide a comprehensive observational database enabling accurate quantitative estimates of the aerosol contribution to the energy budget of the climate system; and (3) quantify the contribution of anthropogenic aerosols to climate and ecological processes. The remote sensing concept of the project is based on precise orbital measurements of the intensity and polarization of sunlight scattered by the atmosphere and the surface with a scanning polarimeter accompanied by a wide-angle multispectral imager-polarimeter. Preparations have already been made for the development of the instrument suite for the Aerosol-UA project, in particular, of the multi-channel scanning polarimeter (ScanPol) designed for remote sensing studies of the global distribution of aerosol and cloud properties (such as particle size, morphology, and composition) in the terrestrial atmosphere by polarimetric and spectrophotometric measurements of the scattered sunlight in a wide range of wavelengths and viewing directions from which a scene location is observed. ScanPol is accompanied by multispectral wide-angle imager-polarimeter (MSIP) that serves to collect information on cloud conditions and Earths surface image. Various components of the polarimeter ScanPol have been prototyped, including the opto-mechanical and electronic assemblies and the scanning mirror controller. Preliminary synthetic data simulations for the retrieval of aerosol parameters over land surfaces have been performed using the Generalized Retrieval of Aerosol and Surface Properties (GRASP) algorithm. Methods for the validation of satellite data using ground-based observations of aerosol properties are also discussed. We assume that designing, building, and launching into orbit a multi

  9. Analysis of Atmospheric Aerosol Data Sets and Application of Radiative Transfer Models to Compute Aerosol Effects

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Bergstrom, Robert W.; Redemann, Jens

    2002-01-01

    This report is the final report for "Analysis of Atmospheric Aerosol Data Sets and Application of Radiative Transfer Models to Compute Aerosol Effects". It is a bibliographic compilation of 29 peer-reviewed publications (published, in press or submitted) produced under this Cooperative Agreement and 30 first-authored conference presentations. The tasks outlined in the various proposals are listed below with a brief comment as to the research performed. Copies of title/abstract pages of peer-reviewed publications are attached.

  10. Automated aerosol Raman spectrometer for semi-continuous sampling of atmospheric aerosol

    NASA Astrophysics Data System (ADS)

    Doughty, David C.; Hill, Steven C.

    2017-02-01

    Raman spectroscopy (RS) is useful in characterizing atmospheric aerosol. It is not commonly used in studying ambient particles partly because automated instrumentation for aerosol RS has not been available. Battelle (Columbus, Ohio, USA) has developed the Resource Effective Bioidentification System (REBS) for automated detection of airborne bioagents based on RS. We use a version of the REBS that measures Raman spectra of one set of particles while the next set of particles is collected from air, then moves the newly collected particles to the analysis region and repeats. Here we investigate the use of the REBS as the core of a general-purpose automated Aerosol Raman Spectrometer (ARS) for atmospheric applications. This REBS-based ARS can be operated as a line-scanning Raman imaging spectrometer. Spectra measured by this ARS for single particles made of polystyrene, black carbon, and several other materials are clearly distinguishable. Raman spectra from a 15 min ambient sample (approximately 35-50 particles, 158 spectra) were analyzed using a hierarchical clustering method to find that the cluster spectra are consistent with soot, inorganic aerosol, and other organic compounds. The ARS ran unattended, collecting atmospheric aerosol and measuring spectra for a 7 hr period at 15-min intervals. A total of 32,718 spectra were measured; 5892 exceeded a threshold and were clustered during this time. The number of particles exhibiting the D-G bands of amorphous carbon plotted vs time (at 15-min intervals) increases during the morning commute, then decreases. This data illustrates the potential of the ARS to measure thousands of time resolved aerosol Raman spectra in the ambient atmosphere over the course of several hours. The capability of this ARS for automated measurements of Raman spectra should lead to more extensive RS-based studies of atmospheric aerosols.

  11. Formation of nitrogenated organic aerosols in the Titan upper atmosphere

    PubMed Central

    Imanaka, Hiroshi; Smith, Mark A.

    2010-01-01

    Many aspects of the nitrogen fixation process by photochemistry in the Titan atmosphere are not fully understood. The recent Cassini mission revealed organic aerosol formation in the upper atmosphere of Titan. It is not clear, however, how much and by what mechanism nitrogen is incorporated in Titan’s organic aerosols. Using tunable synchrotron radiation at the Advanced Light Source, we demonstrate the first evidence of nitrogenated organic aerosol production by extreme ultraviolet–vacuum ultraviolet irradiation of a N2/CH4 gas mixture. The ultrahigh-mass-resolution study with laser desorption ionization-Fourier transform-ion cyclotron resonance mass spectrometry of N2/CH4 photolytic solid products at 60 and 82.5 nm indicates the predominance of highly nitrogenated compounds. The distinct nitrogen incorporations at the elemental abundances of H2C2N and HCN, respectively, are suggestive of important roles of H2C2N/HCCN and HCN/CN in their formation. The efficient formation of unsaturated hydrocarbons is observed in the gas phase without abundant nitrogenated neutrals at 60 nm, and this is confirmed by separately using 13C and 15N isotopically labeled initial gas mixtures. These observations strongly suggest a heterogeneous incorporation mechanism via short lived nitrogenated reactive species, such as HCCN radical, for nitrogenated organic aerosol formation, and imply that substantial amounts of nitrogen is fixed as organic macromolecular aerosols in Titan’s atmosphere. PMID:20616074

  12. Lidar determination of the composition of atmosphere aerosols

    NASA Technical Reports Server (NTRS)

    Wright, M. L.

    1980-01-01

    Theoretical and experimental studies of the feasibility of using DIfferential SCatter (DISC) lidar to measure the composition of atmospheric aerosols are described. This technique involves multiwavelength measurements of the backscatter cross section of aerosols in the middle infrared, where a number of materials display strong restrahlen features that significantly modulate the backscatter spectrum. The theoretical work indicates that a number of materials of interest, including sulfuric acid, ammonium sulfate, and silicates, can be discriminated among with a CO2 lidar. An initial evaluation of this procedure was performed in which cirrus clouds and lower altitude tropospheric aerosols were developed. The observed ratio spectrum of the two types of aerosol displays structure that is in crude accord with theoretical expectations.

  13. Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols.

    PubMed

    Kourtchev, Ivan; Giorio, Chiara; Manninen, Antti; Wilson, Eoin; Mahon, Brendan; Aalto, Juho; Kajos, Maija; Venables, Dean; Ruuskanen, Taina; Levula, Janne; Loponen, Matti; Connors, Sarah; Harris, Neil; Zhao, Defeng; Kiendler-Scharr, Astrid; Mentel, Thomas; Rudich, Yinon; Hallquist, Mattias; Doussin, Jean-Francois; Maenhaut, Willy; Bäck, Jaana; Petäjä, Tuukka; Wenger, John; Kulmala, Markku; Kalberer, Markus

    2016-10-13

    Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks.

  14. Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Kourtchev, Ivan; Giorio, Chiara; Manninen, Antti; Wilson, Eoin; Mahon, Brendan; Aalto, Juho; Kajos, Maija; Venables, Dean; Ruuskanen, Taina; Levula, Janne; Loponen, Matti; Connors, Sarah; Harris, Neil; Zhao, Defeng; Kiendler-Scharr, Astrid; Mentel, Thomas; Rudich, Yinon; Hallquist, Mattias; Doussin, Jean-Francois; Maenhaut, Willy; Bäck, Jaana; Petäjä, Tuukka; Wenger, John; Kulmala, Markku; Kalberer, Markus

    2016-10-01

    Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks.

  15. Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols

    PubMed Central

    Kourtchev, Ivan; Giorio, Chiara; Manninen, Antti; Wilson, Eoin; Mahon, Brendan; Aalto, Juho; Kajos, Maija; Venables, Dean; Ruuskanen, Taina; Levula, Janne; Loponen, Matti; Connors, Sarah; Harris, Neil; Zhao, Defeng; Kiendler-Scharr, Astrid; Mentel, Thomas; Rudich, Yinon; Hallquist, Mattias; Doussin, Jean-Francois; Maenhaut, Willy; Bäck, Jaana; Petäjä, Tuukka; Wenger, John; Kulmala, Markku; Kalberer, Markus

    2016-01-01

    Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks. PMID:27733773

  16. The radiative effect of aerosols in the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Wang, W.-C.; Domoto, G. A.

    1974-01-01

    A modified two-flux approximation is employed to compute the transfer of radiation in a finite, inhomogeneous, turbid atmosphere. A perturbation technique is developed to allow the treatment of nongray gaseous absorption with multiple scattering. The perturbation method, which employs a backscatter factor as a parameter, can be used with anisotropic particle scattering as well as Rayleigh scattering. This method is used to study the effect of aerosols on radiative solar heating and infrared cooling as well as the radiative-convective temperature distribution in the earth's atmosphere. It is found that the effect of aerosols in the infrared cannot be neglected; while in the visible, the effect can be of the same order as that due to absorption by water vapor. For a high surface albedo (greater than 0.30) heating of the earth-atmosphere system results due to the presence of aerosols. The aerosols also reduce the amount of convection needed to maintain a stable atmosphere. For the case of a dense haze a temperature inversion is found to exist close to the ground.

  17. PREDICTION OF MULTICOMPONENT INORGANIC ATMOSPHERIC AEROSOL BEHAVIOR. (R824793)

    EPA Science Inventory

    Many existing models calculate the composition of the atmospheric aerosol system by solving a set of algebraic equations based on reversible reactions derived from thermodynamic equilibrium. Some models rely on an a priori knowledge of the presence of components in certain relati...

  18. a Study of the Origin of Atmospheric Organic Aerosols

    NASA Astrophysics Data System (ADS)

    Hildemann, Lynn Mary

    1990-01-01

    The sources of ambient organic particulate matter in urban areas are investigated through a program of emission source measurements, atmospheric measurements, and mathematical modeling of source/receptor relationships. A dilution sampler intended to collect fine organic aerosol from combustion sources is designed to simulate atmospheric cooling and dilution processes, so that organic vapors which condense under ambient conditions will be collected as particulate matter. This system is used to measure the emissions from a boiler burning distillate oil, a home fireplace, catalyst and noncatalyst automobiles, heavy-duty diesel trucks, natural gas home appliances, and meat cooking operations. Alternate techniques are used to sample the particulate matter emitted from cigarette smoking, a roofing tar pot, paved road dust, brake lining wear, tire wear, and vegetative detritus. The bulk chemical characteristics of the fine aerosol fraction are presented for each source. Over half of the fine aerosol mass emitted from automobiles, wood burning, meat cooking, home appliances, cigarettes, and tar pots is shown to consist of organic compounds. The organic material collected from these sources is analyzed using high-resolution gas chromatography. Using a simple analytical protocol, a quantitative, 50-parameter characterization of the elutable fine organic aerosol emitted from each source type is obtained, which proves to be a unique fingerprint that can be used to distinguish most sources from each other. A mathematical model is used to predict the characteristics of fine ambient organic aerosol in the Los Angeles area that would prevail if the primary organic emissions are transported without chemical reaction. The model is found to track the seasonal variations observed in the ambient aerosol at the three sites studied. Emissions from vehicles and fireplaces are identified as significant sources of solvent-extractable organic aerosol. Differences between the model

  19. Chemical Composition of Atmospheric Aerosols Above a Pristine South East Asian Rainforest

    NASA Astrophysics Data System (ADS)

    Robinson, N. H.; Allan, J. D.; Williams, P. I.; Coe, H.; Hamilton, J.; Chen, Q.; Martin, S.; Trembath, J.

    2009-04-01

    The tropics emit a huge amount of volatile organic compounds (VOCs) into the Earth's atmosphere. The processes by which these gases are oxidised to form secondary organic aerosol (SOA) are currently not well understood or quantified. Intensive field measurements were carried out as part of the Oxidant and Particle Photochemical Processes (OP3) and the Aerosol Coupling in the Earth System (ACES) projects around pristine rainforest in Malaysian Borneo. This is the first campaign of its type in a South East Asian rainforest. We present detailed organic aerosol composition measurements made using an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) at Bukit Atur, a Global Atmosphere Watch site located in the Danum Valley Conservation Area. This is a state-of-the-art field deployable instrument that can provide real time composition, mass loading and aerodynamic particle sizing information. In addition, the mass spectral resolution is sufficient to perform an analysis of the elemental composition of the organic species present. Other tools such as positive matrix factorisation (PMF) have been used to help assess the relative source contributions to the organic aerosol. A suite of supporting aerosol and gas phase measurements were made, including size resolved number concentration measurements with Differential Mobility Particle Sizer (DMPS), as well as absorption measurements made with a Multi-Angle Absorption Photometer (MAAP). The ground site data are compared with Aerodyne Compact Time of Flight Aerosol Mass Spectrometer (C-ToF-AMS) measurements made on the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft. Airborne measurements were made above pristine rainforest surrounding the Danum Valley site, as well as nearby oil palm agricultural sites and palm oil rendering plants. Airborne hygroscopicity was measured using a Droplet Measurement Technology Cloud Condensation Nuclei counter (DMT CCN counter) in

  20. Clouds, aerosols, and photochemistry in the Jovian atmosphere

    NASA Technical Reports Server (NTRS)

    West, R. A.; Strobel, D. F.; Tomasko, M. G.

    1986-01-01

    An assessment is made of the development status of concepts for cloud and aerosol compositions, vertical and horizontal distributions, and microphysical properties, in the Jovian upper troposphere and stratosphere. Attention is given to several key photochemical species' relationships to aerosol formation as well as their transport process implications, treating photochemistry in the context of comparative planetology and noting differences and similarities among the outer planet atmospheres; since this approach emphasizes observational data, a variegated assortment of ground-based and spacecraft observations is assembled. Current views on the tropospheric distribution of clouds are challenged, and a rationale is presented for alternative accounts.

  1. Clouds, aerosols, and photochemistry in the Jovian atmosphere

    NASA Astrophysics Data System (ADS)

    West, R. A.; Strobel, D. F.; Tomasko, M. G.

    1986-03-01

    An assessment is made of the development status of concepts for cloud and aerosol compositions, vertical and horizontal distributions, and microphysical properties, in the Jovian upper troposphere and stratosphere. Attention is given to several key photochemical species' relationships to aerosol formation as well as their transport process implications, treating photochemistry in the context of comparative planetology and noting differences and similarities among the outer planet atmospheres; since this approach emphasizes observational data, a variegated assortment of ground-based and spacecraft observations is assembled. Current views on the tropospheric distribution of clouds are challenged, and a rationale is presented for alternative accounts.

  2. Diesel Aerosol Sampling in the Atmosphere

    SciTech Connect

    David Kittelson; Jason Johnson; Winthrop Watts; Qiang Wei; Marcus Drayton; Dwane Paulsen; Nicolas Bukowiecki

    2000-06-19

    The University of Minnesota Center for Diesel Research along with a research team including Caterpillar, Cummins, Carnegie Mellon University, West Virginia University (WVU), Paul Scherrer Institute in Switzerland, and Tampere University in Finland have performed measurements of Diesel exhaust particle size distributions under real-world dilution conditions. A mobile aerosol emission laboratory (MEL) equipped to measure particle size distributions, number concentrations, surface area concentrations, particle bound PAHs, as well as CO 2 and NO x concentrations in real time was built and will be described. The MEL was used to follow two different Cummins powered tractors, one with an older engine (L10) and one with a state-of-the-art engine (ISM), on rural highways and measure particles in their exhaust plumes. This paper will describe the goals and objectives of the study and will describe representative particle size distributions observed in roadway experiments with the truck powered by the ISM engine.

  3. Heterogeneous Uptake of HO2 Radicals onto Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    George, I. J.; Brooks, B.; Goddard, A.; Whalley, L. K.; Baeza-Romero, M. T.; Heard, D. E.

    2010-12-01

    The hydroxyl (OH) and hydroperoxyl (HO2) radicals, known collectively as HOx radicals, are the key reactants that control the oxidative capacity of the troposphere and the atmospheric lifetimes and concentrations of most trace reactive species, i.e. NOx, O3 and volatile organic compounds. Therefore, in order to gain an overall understanding of atmospheric chemistry and to predict the fate of atmospheric pollutants, a detailed knowledge of the sources and sinks of HOx species and their steady-state atmospheric concentrations is crucial. To this end, field measurements of atmospheric HOx concentrations have been recently compared to model predictions to gauge our level of understanding of atmospheric chemistry of trace reactive species. Box models incorporating known gas-phase chemistry have significantly overpredicted steady-state HO2 levels in comparison to field observations, suggesting heterogeneous uptake onto aerosols as a possible missing atmospheric sink for HO2 radicals [1-2]. However, relatively few laboratory studies have been performed to determine the kinetic parameters for HO2 loss onto aerosols, and thus the ability to assess the impact of this mechanism on HOx levels is limited. The goal of this laboratory study is to improve our understanding of the tropospheric HOx budget by measuring HO2 uptake kinetics onto aerosol particles. In this work, HO2 radicals were produced by the photolysis of water vapour and the FAGE (Fluorescence Assay by Gas Expansion) technique was used to monitor HO2 loss kinetics onto aerosol particles in an aerosol flow tube setup. FAGE is a highly sensitive laser-induced fluorescence based detection method for HOx radicals that has allowed for kinetic measurements to be performed under low HO2 concentrations minimizing gas-phase HO2 self reaction, i.e. for [HO2] < 109 molecules cm-3. The mass accommodation coefficient was determined by measuring HO2 uptake onto Cu(II)-doped ammonium sulfate aerosols. Reactive uptake coefficients

  4. Characterisation of secondary organic aerosol formed during cloud condensation-evaporation cycles from isoprene photooxidation (CUMULUS project)

    NASA Astrophysics Data System (ADS)

    Giorio, Chiara; Bregonzio, Lola; Siekmann, Frank; Temime-Roussel, Brice; Ravier, Sylvain; Pangui, Edouard; Tapparo, Andrea; Kalberer, Markus; Monod, Anne; Doussin, Jean-François

    2014-05-01

    Biogenic volatile organic compounds (BVOCs) undergo many reactions in the atmosphere and form a wide range of oxidised and water-soluble compounds. These compounds could partition into atmospheric water droplets, and react within the aqueous phase producing higher molecular weight and less volatile compounds which could remain in the particle phase after water evaporation (Ervens et al., 2011). The aim of this work is the characterisation of secondary organic aerosol (SOA) formed from the photooxidation of isoprene and the effect of cloud water on SOA formation and composition. The experiments were performed during the CUMULUS project (CloUd MULtiphase chemistry of organic compoUndS in the troposphere), at the 4.2 m3 stainless steel CESAM chamber at LISA (Wang et al., 2011). In each experiment, isoprene was injected in the chamber together with HONO under dry conditions before irradiation. Gas phase compounds were analyzed on-line by a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToF-MS), a Fourier Transform Infrared Spectrometer (FTIR), NOx and O3 analyzers. SOA formation and composition were analysed on-line with a Scanning Mobility Particle Sizer (SMPS) and an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS). Particular attention has been focused on SOA formation and aging during cloud condensation-evaporation cycles simulated in the smog chamber. In all experiments, we observed that during cloud formation water soluble gas-phase oxidation products readily partitioned into cloud droplets and new SOA was promptly produced which partly persisted after cloud evaporation. Chemical composition, elemental ratios and density of SOA, measured with the HR-ToF-AMS, were compared before, during cloud formation and after cloud evaporation. Experiments with other precursors, i.e. methacrolein, and effects of the presence of seeds were also investigated. Ervens, B. et al. (2011) Atmos. Chem. Phys. 11, 11069 11102. Wang, J. et al

  5. Atmospheric aerosol profiling with a bistatic imaging lidar system.

    PubMed

    Barnes, John E; Sharma, N C Parikh; Kaplan, Trevor B

    2007-05-20

    Atmospheric aerosols have been profiled using a simple, imaging, bistatic lidar system. A vertical laser beam is imaged onto a charge-coupled-device camera from the ground to the zenith with a wide-angle lens (CLidar). The altitudes are derived geometrically from the position of the camera and laser with submeter resolution near the ground. The system requires no overlap correction needed in monostatic lidar systems and needs a much smaller dynamic range. Nighttime measurements of both molecular and aerosol scattering were made at Mauna Loa Observatory. The CLidar aerosol total scatter compares very well with a nephelometer measuring at 10 m above the ground. The results build on earlier work that compared purely molecular scattered light to theory, and detail instrument improvements.

  6. Atmospheric aerosol layers over Bangkok Metropolitan Region from CALIPSO observations

    NASA Astrophysics Data System (ADS)

    Bridhikitti, Arika

    2013-06-01

    Previous studies suggested that aerosol optical depth (AOD) from the Earth Observing System satellite retrievals could be used for inference of ground-level air quality in various locations. This application may be appropriate if pollution in elevated atmospheric layers is insignificant. This study investigated the significance of elevated air pollution layers over the Bangkok Metropolitan Region (BMR) from all available aerosol layer scenes taken from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) for years 2007 to 2011. The results show that biomass burning smoke layers alone were the most frequently observed. The smoke layers accounted for high AOD variations and increased AOD levels. In the dry seasons, the smoke layers alone with high AOD levels were likely brought to the BMR via northeasterly to easterly prevailing winds and found at altitudes above the typical BMR mixing heights of approximately 0.7 to 1.5 km. The smoke should be attributed to biomass burning emissions outside the BMR.

  7. Enhancement of atmospheric radiation by an aerosol layer

    NASA Technical Reports Server (NTRS)

    Michelangeli, Diane V.; Yung, Yuk L.; Shia, Run-Lie; Eluszkiewicz, Janusz; Allen, Mark; Crisp, David

    1992-01-01

    The presence of a stratospheric haze layer may produce increases in both the actinic flux and the irradiance below this layer. Such haze layers result from the injection of aerosol-forming material into the stratosphere by volcanic eruptions. Simple heuristic arguments show that the increase in flux below the haze layer, relative to a clear sky case, is a consequence of 'photon trapping'. The magnitude of these flux perturbations, as a function of aerosol properties and illumination conditions, is explored with a new radiative transfer model that can accurately compute fluxes in an inhomogeneous atmosphere with nonconservative scatterers having arbitrary phase function. One calculated consequence of the El Chichon volcanic eruption is an increase in the midday surface actinic flux at 20 deg N latitude, summer, by as much as 45 percent at 2900 A. This increase in flux in the UV-B wavelength range was caused entirely by aerosol scattering, without any reduction in the overhead ozone column.

  8. Equilibration timescale of atmospheric secondary organic aerosol partitioning

    NASA Astrophysics Data System (ADS)

    Shiraiwa, Manabu; Seinfeld, John H.

    2012-12-01

    Secondary organic aerosol (SOA) formed from partitioning of oxidation products of anthropogenic and biogenic volatile organic compounds (VOCs) accounts for a substantial portion of atmospheric particulate matter. In describing SOA formation, it is generally assumed that VOC oxidation products rapidly adopt gas-aerosol equilibrium. Here we estimate the equilibration timescale, τeq, of SOA gas-particle partitioning using a state-of-the-art kinetic flux model. τeq is found to be of order seconds to minutes for partitioning of relatively high volatility organic compounds into liquid particles, thereby adhering to equilibrium gas-particle partitioning. However, τeq increases to hours or days for organic aerosol associated with semi-solid particles, low volatility, large particle size, and low mass loadings. Instantaneous equilibrium partitioning may lead to substantial overestimation of particle mass concentration and underestimation of gas-phase concentration.

  9. Dispersion of aerosol particles in the atmosphere: Fukushima

    NASA Astrophysics Data System (ADS)

    Haszpra, Tímea; Lagzi, István; Tél, Tamás

    2013-04-01

    Investigation of dispersion and deposition of aerosol particles in the atmosphere is an essential issue, because they have an effect on the biosphere and atmosphere. Moreover, aerosol particles have different transport properties and chemical and physical transformations in the atmosphere compared to gas phase air pollutants. The motion of a particle is described by a set of ordinary differential equations. The large-scale dynamics in the horizontal direction can be described by the equations of passive scalar advection, but in the vertical direction a well-defined terminal velocity should be taken into account as a term added to the vertical wind component. In the planetary boundary layer turbulent diffusion has an important role in the particle dispersion, which is taken into account by adding stochastic terms to the deterministic equations above. Wet deposition is also an essential process in the lower levels of the atmosphere, however, its precise parameterization is a challenge. For the simulations the wind field and other necessary data were taken from the ECMWF ERA-Interim database. In the case of the Fukushima Daiichi nuclear disaster (March-April 2011) radioactive aerosol particles were also released in the planetary boundary layer. Simulations (included the continuous and varying emission from the nuclear power plant) will be presented for the period of 14-23 March. Results show that wet deposition also has to be taken into consideration in the lower levels of the atmosphere. Furthermore, dynamical system characteristics are evaluated for the aerosol particle dynamics. The escape rate of particles was estimated both with and without turbulent diffusion, and in both cases when there was no wet deposition and also when wet deposition was taken into consideration.

  10. A study of the origin of atmospheric organic aerosols

    SciTech Connect

    Hildemann, L.M.

    1990-01-01

    The sources of ambient organic particulate matter in urban areas are investigated through a program of emission source measurements, atmospheric measurements, and mathematical modeling of source/receptor relationships. A dilution sampler intended to collect fine organic aerosol from combustion sources is designed to simulate atmospheric cooling and dilution processes, so that organic vapors which condense under ambient conditions will be collected as particulate matter. This system is used to measure the emissions from a boiler burning distillate oil, a home fireplace, catalyst and noncatalyst automobiles, heavy-duty diesel trucks, natural gas home appliances, and meat-cooking operations. Alternate techniques are used to sample the particulate matter emitted from cigarette smoking, a roofing tar pot, paved road dust, brake lining wear, tire wear, and vegetative detritus. The bulk chemical characteristics of the fine aerosol fraction are presented for each source. Over half of the fine aerosol mass emitted from automobiles, wood burning, meat cooking, home appliances, cigarettes, and tar pots is shown to consist of organic compounds. The organic material collected from these sources is analyzed using high-resolution gas chromatography. Using a simple analytical protocol, a quantitative, 50-parameter characterization of the elutable fine organic aerosol emitted from each source type is obtained, which proves to be a unique fingerprint that can be used to distinguish most sources from each other. A mathematical model is used to predict the characteristics of fine ambient organic aerosol in the Los Angeles area that would prevail if the primary organic emissions are transported without chemical reaction. The model is found to track the seasonal variations observed in the ambient aerosol at the three sites studied.

  11. Radiative transfer in finite participating atmospheric aerosol media

    NASA Astrophysics Data System (ADS)

    Degheidy, A. R.; Elgarayhi, A.; Sallah, M.; Shaaban, S. M.

    2014-01-01

    The properties of radiation transfer through a plane-parallel atmospheric aerosol medium has been studied. It has been done by employing Mie theory to calculate the radiation transfer scattering parameters of the medium in the form of extinction, scattering, and absorption efficiencies. Then, the equation of radiative transfer through a plane-parallel atmosphere of aerosol has been solved for partial heat fluxes using two different analytical techniques, namely, the Variational Pomraning -Eddington approximation and Galerkin technique. Average efficiencies over log-normal and modified gamma size distributions are calculated. Therefore, the radiative properties of Carbon, Anthracite, Bituminous, Lignite, and Fly ash have been calculated. The obtained numerical results show very good agreement with each other in addition to the previous published work.

  12. Effect of tropospheric aerosols upon atmospheric infrared cooling rates

    NASA Technical Reports Server (NTRS)

    Harshvardhan, MR.; Cess, R. D.

    1978-01-01

    The effect of tropospheric aerosols on atmospheric infrared cooling rates is investigated by the use of recent models of infrared gaseous absorption. A radiative model of the atmosphere that incorporates dust as an absorber and scatterer of infrared radiation is constructed by employing the exponential kernel approximation to the radiative transfer equation. Scattering effects are represented in terms of a single scattering albedo and an asymmetry factor. The model is applied to estimate the effect of an aerosol layer made of spherical quartz particles on the infrared cooling rate. Calculations performed for a reference wavelength of 0.55 microns show an increased greenhouse effect, where the net upward flux at the surface is reduced by 10% owing to the strongly enhanced downward emission. There is a substantial increase in the cooling rate near the surface, but the mean cooling rate throughout the lower troposphere was only 10%.

  13. Morphological properties of atmospheric aerosol aggregates

    PubMed Central

    Xiong, C.; Friedlander, S. K.

    2001-01-01

    Ultrafine particles (smaller than about 0.1 μm) are often emitted from combustion and other high-temperature processes in the form of fractal-like aggregates composed of solid nanoparticles. Results of a study of atmospheric aggregates are reported. Particles were collected on transmission electron microscope grids fitted on the last two stages of a single-jet eight-stage low-pressure impactor for periods of a few minutes. Photomicrographs of transmission electron microscope grids from the impactor stages were analyzed to obtain the fractal dimension (Df) and prefactor (A) for aggregates. Df increased from near 1 to above 2 as the number of primary particles making up the aggregates increased from 10 to 180. Total particle concentrations in size ranges roughly equivalent to the low-pressure impactor stages were measured with a mobility analyzer and condensation particle counter. In one set of measurements, the fraction of the particles present as aggregates was about 60% for particles with aerodynamic diameters between 50 and 75 nm and 34% for the range 75 to 120 nm. The total aggregate concentration in the 50- to 120-nm size range was about 400 ml−1. The primary particles that make up atmospheric aggregates are more polydisperse than soot aggregates generated from a single laboratory source, an ethane/oxygen flame. Most measurements were made in the Los Angeles area, where the aggregates may represent a signature for diesel emissions. Rural aggregate concentrations in the size range 50 to 120 nm were less than 1% of the concentrations at urban sites. The data will permit better estimates of atmospheric aggregate residence times, transport, and deposition in the lung, optical extinction, and heterogenous nucleation. PMID:11592995

  14. Morphological properties of atmospheric aerosol aggregates.

    PubMed

    Xiong, C; Friedlander, S K

    2001-10-09

    Ultrafine particles (smaller than about 0.1 microm) are often emitted from combustion and other high-temperature processes in the form of fractal-like aggregates composed of solid nanoparticles. Results of a study of atmospheric aggregates are reported. Particles were collected on transmission electron microscope grids fitted on the last two stages of a single-jet eight-stage low-pressure impactor for periods of a few minutes. Photomicrographs of transmission electron microscope grids from the impactor stages were analyzed to obtain the fractal dimension (D(f)) and prefactor (A) for aggregates. D(f) increased from near 1 to above 2 as the number of primary particles making up the aggregates increased from 10 to 180. Total particle concentrations in size ranges roughly equivalent to the low-pressure impactor stages were measured with a mobility analyzer and condensation particle counter. In one set of measurements, the fraction of the particles present as aggregates was about 60% for particles with aerodynamic diameters between 50 and 75 nm and 34% for the range 75 to 120 nm. The total aggregate concentration in the 50- to 120-nm size range was about 400 ml(-1). The primary particles that make up atmospheric aggregates are more polydisperse than soot aggregates generated from a single laboratory source, an ethane/oxygen flame. Most measurements were made in the Los Angeles area, where the aggregates may represent a signature for diesel emissions. Rural aggregate concentrations in the size range 50 to 120 nm were less than 1% of the concentrations at urban sites. The data will permit better estimates of atmospheric aggregate residence times, transport, and deposition in the lung, optical extinction, and heterogeneous nucleation.

  15. Characterising Brazilian biomass burning emissions using WRF-Chem with MOSAIC sectional aerosol

    NASA Astrophysics Data System (ADS)

    Archer-Nicholls, S.; Lowe, D.; Darbyshire, E.; Morgan, W. T.; Bela, M. M.; Pereira, G.; Trembath, J.; Kaiser, J. W.; Longo, K. M.; Freitas, S. R.; Coe, H.; McFiggans, G.

    2014-09-01

    The South American Biomass Burning Analysis (SAMBBA) field campaign took detailed in-situ flight measurements of aerosol during the 2012 dry season to characterise biomass burning aerosol and improve understanding of its impacts on weather and climate. Developments have been made to the Weather research and Forecast model with chemistry (WRF-Chem) model to improve the representation of biomass burning aerosol in the region by coupling a sectional aerosol scheme to the plume rise parameterisation. Brazilian Biomass Burning Emissions Model (3BEM) fire emissions are used, prepared using PREP-CHEM-SRC, and mapped to CBM-Z and MOSAIC species. Model results have been evaluated against remote sensing products, AERONET sites, and four case studies of flight measurements from the SAMBBA campaign. WRF-Chem predicted layers of elevated aerosol loadings (5-20 μg sm-3) of particulate organic matter at high altitude (6-8 km) over tropical forest regions, while flight measurements showed a sharp decrease above 2-4 km altitude. This difference was attributed to the plume-rise parameterisation overestimating injection height. The 3BEM emissions product was modified using estimates of active fire size and burned area for the 2012 fire season, which reduced the fire size. The enhancement factor for fire emissions was increased from 1.3 to 5 to retain reasonable aerosol optical depths (AOD). The smaller fire size lowered the injection height of the emissions, but WRF-Chem still showed elevated aerosol loadings between 4-5 km altitude. Over eastern Cerrado (savannah-like) regions, both modelled and measured aerosol loadings decreased above approximately 4 km altitude. Compared with MODIS satellite data and AERONET sites, WRF-Chem represented AOD magnitude well (between 0.3-1.5) over western tropical forest fire regions in the first half of the campaign, but tended to over-predict them in the second half, when precipitation was more significant. Over eastern Cerrado regions, WRF

  16. Characterising Brazilian biomass burning emissions using WRF-Chem with MOSAIC sectional aerosol

    NASA Astrophysics Data System (ADS)

    Archer-Nicholls, S.; Lowe, D.; Darbyshire, E.; Morgan, W. T.; Bela, M. M.; Pereira, G.; Trembath, J.; Kaiser, J. W.; Longo, K. M.; Freitas, S. R.; Coe, H.; McFiggans, G.

    2015-03-01

    The South American Biomass Burning Analysis (SAMBBA) field campaign took detailed in situ flight measurements of aerosol during the 2012 dry season to characterise biomass burning aerosol and improve understanding of its impacts on weather and climate. Developments have been made to the Weather Research and Forecast model with chemistry (WRF-Chem) model to improve the representation of biomass burning aerosol in the region, by coupling a sectional aerosol scheme to the plume-rise parameterisation. Brazilian Biomass Burning Emissions Model (3BEM) fire emissions are used, prepared using PREP-CHEM-SRC, and mapped to CBM-Z and MOSAIC species. Model results have been evaluated against remote sensing products, AERONET sites, and four case studies of flight measurements from the SAMBBA campaign. WRF-Chem predicted layers of elevated aerosol loadings (5-20 μg sm-3) of particulate organic matter at high altitude (6-8 km) over tropical forest regions, while flight measurements showed a sharp decrease above 2-4 km altitude. This difference was attributed to the plume-rise parameterisation overestimating injection height. The 3BEM emissions product was modified using estimates of active fire size and burned area for the 2012 fire season, which reduced the fire size. The enhancement factor for fire emissions was increased from 1.3 to 5 to retain reasonable aerosol optical depths (AODs). The smaller fire size lowered the injection height of the emissions, but WRF-Chem still showed elevated aerosol loadings between 4-5 km altitude. Over eastern cerrado (savannah-like) regions, both modelled and measured aerosol loadings decreased above approximately 4 km altitude. Compared with MODIS satellite data and AERONET sites, WRF-Chem represented AOD magnitude well (between 0.3-1.5) over western tropical forest fire regions in the first half of the campaign, but tended to over-predict them in the second half, when precipitation was more significant. Over eastern cerrado regions, WRF

  17. Unintended consequences of atmospheric injection of sulphate aerosols.

    SciTech Connect

    Brady, Patrick Vane; Kobos, Peter Holmes; Goldstein, Barry

    2010-10-01

    Most climate scientists believe that climate geoengineering is best considered as a potential complement to the mitigation of CO{sub 2} emissions, rather than as an alternative to it. Strong mitigation could achieve the equivalent of up to -4Wm{sup -2} radiative forcing on the century timescale, relative to a worst case scenario for rising CO{sub 2}. However, to tackle the remaining 3Wm{sup -2}, which are likely even in a best case scenario of strongly mitigated CO{sub 2} releases, a number of geoengineering options show promise. Injecting stratospheric aerosols is one of the least expensive and, potentially, most effective approaches and for that reason an examination of the possible unintended consequences of the implementation of atmospheric injections of sulphate aerosols was made. Chief among these are: reductions in rainfall, slowing of atmospheric ozone rebound, and differential changes in weather patterns. At the same time, there will be an increase in plant productivity. Lastly, because atmospheric sulphate injection would not mitigate ocean acidification, another side effect of fossil fuel burning, it would provide only a partial solution. Future research should aim at ameliorating the possible negative unintended consequences of atmospheric injections of sulphate injection. This might include modeling the optimum rate and particle type and size of aerosol injection, as well as the latitudinal, longitudinal and altitude of injection sites, to balance radiative forcing to decrease negative regional impacts. Similarly, future research might include modeling the optimum rate of decrease and location of injection sites to be closed to reduce or slow rapid warming upon aerosol injection cessation. A fruitful area for future research might be system modeling to enhance the possible positive increases in agricultural productivity. All such modeling must be supported by data collection and laboratory and field testing to enable iterative modeling to increase the

  18. Atmospheric Optical Properties and Spectral Analysis of Desert Aerosols

    NASA Astrophysics Data System (ADS)

    Yvgeni, D.; Karnieli, A.; Kaufman, Y. J.; Andreae, M. O.; Holben, B. N.; Maenhaut, W.

    2002-05-01

    Scientific background Aerosols can interact directly with solar and terrestrial radiation by scattering as well as absorption. In addition, they can indirectly alter the planetary albedo by modifying the properties of clouds. Objectives Investigations have been devoted to two main areas: (1) Aerosol climatology situation in the Negev desert, investigations of physical and chemical characteristics of aerosols, and study of the local and long-range transport trajectory of polluted air masses over the Negev desert; and (2) An estimation of the optical properties throughout the atmospheric column by surface measurements via performance of spectral and statistical analysis of the data received from two measurement systems. Results and conclusions Analyzed data from the Sede Boker site, in the Negev Desert of Israel, shows an increase in aerosol optical depth during the summer seasons and a decrease during winter. One of the possible reasons for this characteristic is an increase of the precipitable water (reaches 3.0-3.5 cm) due to a constant wind stream from the Mediterranean Sea in same time. The highest probability distribution of the aerosol optical depth is in the range of 0.15-0.20; and of the Angstrom parameter is in range of 0.83 - 1.07. During dust storm events, the scattering coefficient range at 670 nm and 440 nm wavelengths were inverted. It was discovered that the dust particles in this case had non-spherical character. Comparison between optical depth, measured through all atmospheric column, and scattering coefficient from surface measurements provides correlation coefficient (r) equal to 0.64. The Angstrom parameter, calculated via optical depth and via scattering coefficient, provides a correlation coefficient of 0.66. Thus we can obtain an estimate of the influence of the surface aerosol situation on column optical properties. The combined analysis of dust cloud altitude and optical depth as a function of the time indicates long-term transport and

  19. Organic nitrogen in rain and aerosol in the eastern Mediterranean atmosphere: An association with atmospheric dust

    NASA Astrophysics Data System (ADS)

    Mace, Kimberly A.; Kubilay, Nilgün; Duce, Robert A.

    2003-05-01

    From March through early May of 2000, rain and bulk aerosol samples were collected at a coastal site on the eastern Mediterranean Sea at Erdemli, Turkey, and analyzed for nitrogen (N) species, including nitrate (NO3-), nitrite (NO2-), ammonium (NH4+), water-soluble organic N, urea, and dissolved free amino acids. Other ions were also analyzed, including Ca2+, Mg2+, K+, Na+, Cl-, and SO42-. Water-soluble organic N was found to contribute ˜17% and ˜26% of the total water-soluble N in rain and aerosols, respectively. Organic N concentrations within rain and aerosols exhibited statistically significant linear relationships to Ca2+ ion (Rsqr ˜ 0.75, P < 0.05), suggesting a relationship to calcite (CaCO3) in atmospheric dust. Kinematic trajectory analyses indicated the origin of winds from arid regions, mainly in northern Africa, in 70% of the aerosols sampled. Earth Probe/Total Ozone Mapping Spectrometer aerosol index data also confirmed the influence of atmospheric dust in the region on days when Ca2+ concentrations were elevated, and trajectory analyses suggested northern Africa as a source region. The combined ion, trajectory, and aerosol index data suggest that organic N is associated with atmospheric dust in this region. Urea N and amino N represented a small percentage of the organic N fraction. In rain and aerosols, urea represented ˜11% and <1%, respectively, of the total organic N. While amino N contributed minimally to organic N totals (˜1% of total organic N in aerosols), the individual amino acids contributing ˜75% of amino N were indicative of biological organisms. Further research is needed to decipher the influence from biology and gas phase adsorption of anthropogenically derived water-soluble organics on organic N totals.

  20. A Decade of Field Changing Atmospheric Aerosol Research ...

    EPA Pesticide Factsheets

    Conference: Gordon Research Conference in Atmospheric Chemistry, July 28 – August 2, 2013, VermontPresentation Type: PosterTitle: An Analysis of EPA’s STAR Program and a Decade of Field Changing Research in Atmospheric AerosolsAuthors: Kristina M. Wagstrom1,2, Sherri W. Hunt31Chemical and Biomolecular Engineering, University of Connecticut, Storrs, CT2AAAS Science and Technology Policy Fellow hosted by U.S. Environmental Protection Agency, National Center for Environmental Research3U.S. Environmental Protection Agency, National Center for Environmental ResearchA number of studies in the past decade have transformed the way we think about atmospheric aerosols. The advances include, but are not limited to, source apportionment of organics using aerosol mass spectrometer data, the volatility basis set approach, quantifying isoprene oxidation, and understanding the role of aqueous oxidation of organics on SOA formation. A series of grants funded by EPA just under ten years ago supported many of these advances. These projects make up the body of work awarded under two solicitations released by the EPA’s Science to Achieve Results (STAR) program: “Measurement, Modeling, and Analysis Methods for Airborne Carbonaceous Fine Particulate Matter” (2003) and “Source Apportionment of Particulate Matter” (2004). Our goal is to present the impact of the STAR solicitations and to show how they have pushed the field forward and led to new questions.In particular

  1. Soiling degradation by atmospheric aerosols in an urban industrial area

    SciTech Connect

    Creighton, P.J. ); Lioy, P.J. ); Haynie, F.C.; Lemons, T.J; Miller, J.L; Gerhart, J. )

    1988-01-01

    The gradual and progressive soiling of structures exposed to the atmosphere is commonplace. Wooden homes required painting every few years for aesthetic purposes as well as for preservation, while public buildings, houses of worship, and statuary require occasional cleaning of their exterior because of gradual soiling. The soilant is usually a component of atmospheric aerosols. This paper presents the results of a study that attempts to identify the components of the atmospheric aerosol primarily responsible for the observed soiling of exposed materials. The site chosen for the study was in Elizabeth, N.J., an urban area with a mix of residential, commercial, and industrial facilities. the test site was close to various sources of aerosols. Since the site is close to major highways on three sides automobile and diesel truck traffic abounds, and road dust is prevalent. Oil refineries and chemical plants lie to the south and south-west, and an international airport is located about 3 1/2 miles away.

  2. Study of clouds and dust aerosols in the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Chen-Chen, H.; Pérez-Hoyos, S.; Sánchez-Lavega, A.

    2017-03-01

    Observation of Mars’ atmosphere has evolved to a state of permanent monitoring of its main components. In this work, we focus on the study of clouds and dust aerosols in the Martian atmosphere by means of spacecraft observations, particularly VMC on-board Mars Express, and surface vehicles, mainly cameras on the MSL rover. Orbiting instrument observations provide a general view of the planet, which allows covering a huge area in a short time. This is very interesting, for example, to study global dust events in Mars. On the other hand, ground-based instruments are better suited to analyse local properties of dust particles from in-situ acquired first hand data.

  3. Chemistry of Atmospheric Aerosols at Pacifichem 2015 Congress

    SciTech Connect

    Nizkorodov, Sergey

    2016-12-28

    This grant was used to provide participant support for a symposium entitled “Chemistry of Atmospheric Aerosols” at the 2015 International Chemical Congress of Pacific Basin Societies (Pacifichem) that took place in Honolulu, Hawaii, USA, on December 15-20, 2015. The objective was to help attract both distinguished scientists as well as more junior researchers, including graduate students, to this international symposium by reducing the financial barrier for its attendance. It was the second time a symposium devoted to Atmospheric Aerosols was part of the Pacifichem program. This symposium provided a unique opportunity for the scientists from different countries to gather in one place and discuss the cutting edge advances in the cross-disciplinary areas of aerosol research. To achieve the highest possible impact, the PI and the symposium co-organizers actively advertised the symposium by e-mail and by announcements at other conferences. A number of people responded, and the end result was a very busy program with about 100 oral and poster presentation described in the attached PDF file. Presentations by invited speakers occupied approximately 30% of time in each of the sessions. In addition to the invited speakers, each session also had contributed presentations, including those by graduate students and postdoctoral researchers. This symposium gathered established aerosol chemists from a number of countries including United States, Canada, China, Japan, Korea, Australia, Brazil, Hongkong, Switzerland, France, and Germany. There were plenty of time for the attendees to discuss new ideas and potential collaborations both during the oral sessions and at the poster sessions of the symposium. The symposium was very beneficial to graduate student researchers, postdoctoral fellows, and junior researchers whose prior exposure to international aerosol chemistry science had been limited. The symposium provided junior researchers with a much broader perspective of aerosol

  4. Climate Impacts of Atmospheric Sulfate and Black Carbon Aerosols

    SciTech Connect

    Qian, Yun; Song, Qingyuan; Menon, Surabi; Yu, Shaocai; Liu, Shaw C.; Shi, Guangyu; Leung, Lai R.; Luo, Yunfeng

    2008-09-19

    Although the global average surface temperature has increased by about 0.6°C during the last century (IPCC, 2001), some regions such as East Asia, Eastern North America, and Western Europe have cooled rather than warmed during the past decades (Jones, 1988; Qian and Giorgi, 2000). Coherent changes at the regional scale may reflect responses to different climate forcings that need to be understood in order to predict the future net climate response at the global and regional scales under different emission scenarios. Atmospheric aerosols play an important role in global climate change (IPCC 2001). They perturb the earth’s radiative budget directly by scattering and absorbing solar and long wave radiation, and indirectly by changing cloud reflectivity, lifetime, and precipitation efficiency via their role as cloud condensation nuclei. Because aerosols have much shorter lifetime (days to weeks) compared to most greenhouse gases, they tend to concentrate near their emission sources and distribute very unevenly both in time and space. This non-uniform distribution of aerosols, in conjunction with the greenhouse effect, may lead to differential net heating in some areas and net cooling in others (Penner et al. 1994). Sulfate aerosols come mainly from the oxidation of sulfur dioxide (SO2) emitted from fossil fuel burning. Black carbon aerosols are directly emitted during incomplete combustion of biomass, coal, and diesel derived sources. Due to the different optical properties, sulfate and black carbon affect climate in different ways. Because of the massive emissions of sulfur and black carbon that accompany the rapid economic expansions in East Asia, understanding the effects of aerosols on climate is particularly important scientifically and politically in order to develop adaptation and mitigation strategies.

  5. Atmospheric Carbon Dioxide and Aerosols: Effects of Large Increases on Global Climate

    ERIC Educational Resources Information Center

    Science, 1971

    1971-01-01

    Mathematical models indicate increasing atmospheric carbon dioxide causes an increase in surface temperature at a decreasing rate, and the rate of temperature decrease caused by increasing aerosols increases with aerosol concentration. (AL)

  6. Natural sources of atmospheric aerosols influencing air quality across Europe.

    PubMed

    Viana, M; Pey, J; Querol, X; Alastuey, A; de Leeuw, F; Lükewille, Anke

    2014-02-15

    Atmospheric aerosols are emitted by natural and anthropogenic sources. Contributions from natural sources to ambient aerosols vary widely with time (inter-annual and seasonal variability) and as a function of the distance to source regions. This work aims to identify the main natural sources of atmospheric aerosols affecting air quality across Europe. The origin, frequency, magnitude, and spatial and temporal variability of natural events were assessed for the years 2008 and 2009. The main natural sources of atmospheric aerosols identified were African dust, sea spray and wildfires. Primary biological particles were not included in the present work. Volcanic eruptions did not affect air quality significantly in Europe during the study period. The impact of natural episodes on air quality was significant in Southern and Western Europe (Cyprus, Spain, France, UK, Greece, Malta, Italy and Portugal), where they contributed to surpass the PM10 daily and annual limit values. In Central and Northern Europe (Germany, Austria and Latvia) the impact of these events was lower, as it resulted in the exceedance of PM daily but not annual limit values. Contributions from natural sources to mean annual PM10 levels in 2008 and 2009 ranged between 1 and 2 μg/m(3) in Italy, France and Portugal, between 1 and 4 μg/m(3) in Spain (10 μg/m(3) when including the Canary Islands), 5 μg/m(3) in UK, between 3 and 8 μg/m(3) in Greece, and reached up to 13 μg/m(3) in Cyprus. The evaluation of the number of monitoring stations per country reporting natural exceedances of the daily limit value (DLV) is suggested as a potential tool for air quality monitoring networks to detect outliers in the assessment of natural contributions. It is strongly suggested that a reference methodology for the identification and quantification of African dust contributions should be adopted across Europe.

  7. Semi-quantitative characterisation of ambient ultrafine aerosols resulting from emissions of coal fired power stations.

    PubMed

    Hinkley, J T; Bridgman, H A; Buhre, B J P; Gupta, R P; Nelson, P F; Wall, T F

    2008-02-25

    Emissions from coal fired power stations are known to be a significant anthropogenic source of fine atmospheric particles, both through direct primary emissions and secondary formation of sulfate and nitrate from emissions of gaseous precursors. However, there is relatively little information available in the literature regarding the contribution emissions make to the ambient aerosol, particularly in the ultrafine size range. In this study, the contribution of emissions to particles smaller than 0.3 mum in the ambient aerosol was examined at a sampling site 7 km from two large Australian coal fired power stations equipped with fabric filters. A novel approach was employed using conditional sampling based on sulfur dioxide (SO(2)) as an indicator species, and a relatively new sampler, the TSI Nanometer Aerosol Sampler. Samples were collected on transmission electron microscope (TEM) grids and examined using a combination of TEM imaging and energy dispersive X-ray (EDX) analysis for qualitative chemical analysis. The ultrafine aerosol in low SO(2) conditions was dominated by diesel soot from vehicle emissions, while significant quantities of particles, which were unstable under the electron beam, were observed in the high SO(2) samples. The behaviour of these particles was consistent with literature accounts of sulfate and nitrate species, believed to have been derived from precursor emissions from the power stations. A significant carbon peak was noted in the residues from the evaporated particles, suggesting that some secondary organic aerosol formation may also have been catalysed by these acid seed particles. No primary particulate material was observed in the minus 0.3 mum fraction. The results of this study indicate the contribution of species more commonly associated with gas to particle conversion may be more significant than expected, even close to source.

  8. Atmospheric aerosol and gas sensing using Scheimpflug lidar

    NASA Astrophysics Data System (ADS)

    Mei, Liang; Brydegaard, Mikkel

    2015-04-01

    This work presents a new lidar technique for atmospheric remote sensing based on Scheimpflug principle, which describes the relationship between nonparallel image- and object-planes[1]. When a laser beam is transmitted into the atmosphere, the implication is that the backscattering echo of the entire illuminated probe volume can be in focus simultaneously without diminishing the aperture. The range-resolved backscattering echo can be retrieved by using a tilted line scan or two-dimensional CCD/CMOS camera. Rather than employing nanosecond-pulsed lasers, cascade detectors, and MHz signal sampling, all of high cost and complexity, we have developed a robust and inexpensive atmospheric lidar system based on compact laser diodes and array detectors. We present initial applications of the Scheimpflug lidar for atmospheric aerosol monitoring in bright sunlight, with a 3 W, 808 nm CW laser diode. Kilohertz sampling rates are also achieved with applications for wind speed and entomology [2]. Further, a proof-of-principle demonstration of differential absorption lidar (DIAL) based on the Scheimpflug lidar technique is presented [3]. By utilizing a 30 mW narrow band CW laser diode emitting at around 760 nm, the detailed shape of an oxygen absorption line can be resolved remotely with an integration time of 6 s and measurement cycle of 1 minute during night time. The promising results demonstrated in this work show potential for the Scheimpflug lidar technique for remote atmospheric aerosol and gas sensing, and renews hope for robust and realistic instrumentation for atmospheric lidar sensing. [1] F. Blais, "Review of 20 years of range sensor development," Journal of Electronic Imaging, vol. 13, pp. 231-243, Jan 2004. [2] M. Brydegaard, A. Gebru, and S. Svanberg, "Super resolution laser radar with blinking atmospheric particles - application to interacting flying insects " Progress In Electromagnetics Research, vol. 147, pp. 141-151, 2014. [3] L. Mei and M. Brydegaard

  9. Metal and Metalloid Contaminants in Atmospheric Aerosols from Mining Operations

    PubMed Central

    Csavina, Janae; Landázuri, Andrea; Wonaschütz, Anna; Rine, Kyle; Rheinheimer, Paul; Barbaris, Brian; Conant, William; Sáez, A. Eduardo; Betterton, Eric A.

    2013-01-01

    Mining operations are potential sources of airborne metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, with potential deleterious effects on human health and ecology. Fine particulates such as those resulting from smelting operations may disperse more readily into the environment than coarser tailings dust. Fine particles also penetrate more deeply into the human respiratory system, and may become more bioavailable due to their high specific surface area. In this work, we report the size-fractionated chemical characterization of atmospheric aerosols sampled over a period of a year near an active mining and smelting site in Arizona. Aerosols were characterized with a 10-stage (0.054 to 18 μm aerodynamic diameter) multiple orifice uniform deposit impactor (MOUDI), a scanning mobility particle sizer (SMPS), and a total suspended particulate (TSP) collector. The MOUDI results show that arsenic and lead concentrations follow a bimodal distribution, with maxima centered at approximately 0.3 and 7.0 μm diameter. We hypothesize that the sub-micron arsenic and lead are the product of condensation and coagulation of smelting vapors. In the coarse size, contaminants are thought to originate as aeolian dust from mine tailings and other sources. Observation of ultrafine particle number concentration (SMPS) show the highest readings when the wind comes from the general direction of the smelting operations site. PMID:23441050

  10. Transition from Gaseous Compounds to Aerosols in Titan's Atmosphere

    NASA Technical Reports Server (NTRS)

    Lebonnois, Sebastien; Bakes, E. L. O.; McKay, Christopher P.; DeVincenzi, Donald (Technical Monitor)

    2002-01-01

    We investigate the chemical transition of simple molecules like C2H2 and HCN into aerosol particles in the context of Titan's atmosphere. Experiments that synthesize analogs (tholins) for these aerosols can help understand and constrain these polymerization mechanisms. Using information available from these experiments, we suggest chemical pathways that can link simple molecules to macromolecules, that will be the precursors to aerosol particles: polymers of acetylene and cyanoacetylene, polycyclic aromatics (PAHs), polymers of HCN and other nitriles, and polynes. Although our goal here is not to build a detailed kinetic model for this transition, we propose parameterizations to estimate the production rates of these macromolecules, their C/N and C/H ratios, and the loss of parent molecules (C2H2, HCN, HC3N and other nitriles, C6H6) from the gas phase to the haze. We use a 1-dimensional photochemical model of Titan's atmosphere to estimate the formation rate of precursors macromolecules. We find a production zone slightly lower than 200 km altitude with a total production rate of 4 x 10(exp -14) g/ sq cm s and a C/N approx. = 4. These results are compared with experimental data, and to microphysical models requirements. The Cassini/Huygens mission will bring a detailed picture of the haze distribution and properties, that will be a great challenge for our understanding of those chemical processes.

  11. Sources and atmospheric transformations of semivolatile organic aerosols

    NASA Astrophysics Data System (ADS)

    Grieshop, Andrew P.

    Fine atmospheric particulate matter (PM2.5) is associated with increased mortality, a fact which led the EPA to promulgate a National Ambient Air Quality Standard (NAAQS) for PM2.5 in 1997. Organic material contributes a substantial portion of the PM2.5 mass; organic aerosols (OA) are either directly emitted (primary OA or POA) or formed via the atmospheric oxidation of volatile precursor compounds as secondary OA (SOA). The relative contributions of POA and SOA to atmospheric OA are uncertain, as are the contributions from various source classes (e.g. motor vehicles, biomass burning). This dissertation first assesses the importance of organic PM within the context of current US air pollution regulations. Most control efforts to date have focused on the inorganic component of PM. Although growing evidence strongly implicates OA, especially which from motor vehicles, in the health effects of PM, uncertain and complex source-receptor relationships for OA discourage its direct control for NAAQS compliance. Analysis of both ambient data and chemical transport modeling results indicate that OA does not play a dominant role in NAAQS violations in most areas of the country under current and likely future regulations. Therefore, new regulatory approaches will likely be required to directly address potential health impacts associated with OA. To help develop the scientific understanding needed to better regulate OA, this dissertation examined the evolution of organic aerosol emitted by combustion systems. The current conceptual model of POA is that it is non-volatile and non-reactive. Both of these assumptions were experimental investigated in this dissertation. Novel dilution measurements were carried out to investigate the gas-particle partitioning of OA at atmospherically-relevant conditions. The results demonstrate that POA from combustion sources is semivolatile. Therefore its gas-particle partitioning depends on temperature and atmospheric concentrations; heating and

  12. Sulfuric acid aerosols in the atmospheres of the terrestrial planets

    NASA Astrophysics Data System (ADS)

    McGouldrick, Kevin; Toon, Owen B.; Grinspoon, David H.

    2011-08-01

    Clouds and hazes composed of sulfuric acid are observed to exist or postulated to have once existed on each of the terrestrial planets with atmospheres in our solar system. Venus today maintains a global cover of clouds composed of a sulfuric acid/water solution that extends in altitude from roughly 50 km to roughly 80 km. Terrestrial polar stratospheric clouds (PSCs) form on stratospheric sulfuric acid aerosols, and both PSCs and stratospheric aerosols play a critical role in the formation of the ozone hole. Stratospheric aerosols can modify the climate when they are enhanced following volcanic eruptions, and are a current focus for geoengineering studies. Rain is made more acidic by sulfuric acid originating from sulfur dioxide generated by industry on Earth. Analysis of the sulfur content of Martian rocks has led to the hypothesis that an early Martian atmosphere, rich in SO 2 and H 2O, could support a sulfur-infused hydrological cycle. Here we consider the plausibility of frozen sulfuric acid in the upper clouds of Venus, which could lead to lightning generation, with implications for observations by the European Space Agency's Venus Express and the Japan Aerospace Exploration Agency's Venus Climate Orbiter (also known as Akatsuki). We also present simulations of a sulfur-rich early Martian atmosphere. We find that about 40 cm/yr of precipitation having a pH of about 2.0 could fall in an early Martian atmosphere, assuming a surface temperature of 273 K, and SO 2 generation rates consistent with the formation of Tharsis. This modeled acid rain is a powerful sink for SO 2, quickly removing it and preventing it from having a significant greenhouse effect.

  13. Infrared Absorption by Atmospheric Aerosols in Mexico City during MILAGRO.

    NASA Astrophysics Data System (ADS)

    Kelley, K. L.; Mangu, A.; Gaffney, J. S.; Marley, N. A.

    2007-12-01

    found as colloidal materials in surface and groundwaters (4). Examples of the IR spectra obtained and variance as a function of time at the two sites will be presented. The spectra are taken in Kubelka - Munk format, which also allows the infrared absorption strengths to be evaluated as function of wavelength. The wavelength dependence of the aerosol complex refractive index (m = n + ik) in the infrared spectral region is determined by application of the Kramers Kronig function. The importance of the aerosol absorption in the infrared spectral region to radiative forcing will be discussed. 1. N.A. Marley, J.S. Gaffney, and M.M. Cunningham,Environ. Sci. Technol. 27 2864-2869 (1993). 2. N.A. Marley, J.S. Gaffney, and M.M. Cunningham, Spectroscopy 7 44-53 (1992). 3. J.S. Gaffney and N.A. Marley, Atmospheric Environment, New Directions contribution, 32, 2873-2874 (1998). 4. N.A. Marley, J.S. Gaffney, and K.A. Orlandini, Chapter 7 in Humic/Fulvic Acids and Organic Colloidal Materials in the Environment, ACS Symposium Series 651, American Chemical Society, Washington, D.C., pp. 96-107, 1996. This work was performed as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX- Mex) under the support of the Atmospheric Science Program. This research was supported by the Office of Science (BER), U.S. Department of Energy, Grant No. DE-FG02-07ER64328.

  14. Basaltic fissure eruptions, plume heights, and atmospheric aerosols

    NASA Technical Reports Server (NTRS)

    Stothers, R. B.; Wolff, J. A.; Self, S.; Rampino, M. R.

    1986-01-01

    Convective plumes that rise above Hawaiian-style fire fountains consist of volcanic gases, aerosols, fine ash, and entrained heated air. Plume theory has been applied to observational estimates of the rate of thermal energy release from large fire fountains. The theoretically predicted heights of maintained plumes agree very well with the heights found from actual observations. Predicted plume heights for both central-vent (point-source) and fissure (line-source) eruptions indicate a stratospheric penetration by plumes that form over vents with very high magma-production rates. Flood basalt fissure eruptions that produce individual lava flows with volumes greater than 100 cu km at very high mass eruption rates are capable of injecting large quantities of sulfate aerosols into the lower stratosphere, with potentially drastic short-term atmospheric consequences, like acid precipitation, darkening of the sky, and climatic cooling.

  15. Field and Laboratory Studies of Atmospheric Organic Aerosol

    NASA Astrophysics Data System (ADS)

    Coggon, Matthew Mitchell

    This thesis is the culmination of field and laboratory studies aimed at assessing processes that affect the composition and distribution of atmospheric organic aerosol. An emphasis is placed on measurements conducted using compact and high-resolution Aerodyne Aerosol Mass Spectrometers (AMS). The first three chapters summarize results from aircraft campaigns designed to evaluate anthropogenic and biogenic impacts on marine aerosol and clouds off the coast of California. Subsequent chapters describe laboratory studies intended to evaluate gas and particle-phase mechanisms of organic aerosol oxidation. The 2013 Nucleation in California Experiment (NiCE) was a campaign designed to study environments impacted by nucleated and/or freshly formed aerosol particles. Terrestrial biogenic aerosol with > 85% organic mass was observed to reside in the free troposphere above marine stratocumulus. This biogenic organic aerosol (BOA) originated from the Northwestern United States and was transported to the marine atmosphere during periodic cloud-clearing events. Spectra recorded by a cloud condensation nuclei counter demonstrated that BOA is CCN active. BOA enhancements at latitudes north of San Francisco, CA coincided with enhanced cloud water concentrations of organic species such as acetate and formate. Airborne measurements conducted during the 2011 Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) were aimed at evaluating the contribution of ship emissions to the properties of marine aerosol and clouds off the coast of central California. In one study, analysis of organic aerosol mass spectra during periods of enhanced shipping activity yielded unique tracers indicative of cloud-processed ship emissions (m/z 42 and 99). The variation of their organic fraction (f42 and f 99) was found to coincide with periods of heavy (f 42 > 0.15; f99 > 0.04), moderate (0.05 < f42 < 0.15; 0.01 < f99 < 0.04), and negligible (f42 < 0.05; f99 < 0.01) ship influence. Application of

  16. Upper-atmosphere Aerosols: Properties and Natural Cycles

    NASA Technical Reports Server (NTRS)

    Turco, Richard P.

    1992-01-01

    The middle atmosphere is rich in its variety of particulate matter, which ranges from meteorite debris, to sulfate aerosols, to polar stratospheric ice clouds. Volcanic eruptions strongly perturb the stratospheric sulfate (Junge) layer. High-altitude 'noctilucent' ice clouds condense at the summer mesopause. The properties of these particles, including their composition, sizes, and geographical distribution, are discussed, and their global effects, including chemical, radiative, and climatic roles, are reviewed. Polar stratospheric clouds (PSCs) are composed of water and nitric acid in the form of micron-sized ice crystals. These particles catalyze reactions of chlorine compounds that 'activate' otherwise inert chlorine reservoirs, leading to severe ozone depletions in the southern polar stratosphere during austral spring. PSCs also modify the composition of the polar stratosphere through complex physiocochemical processes, including dehydration and denitrification, and the conversion of reactive nitrogen oxides into nitric acid. If water vapor and nitric acid concentrations are enhanced by high-altitude aircraft activity, the frequency, geographical range, and duration of PSCs might increase accordingly, thus enhancing the destruction of the ozone layer (which would be naturally limited in geographical extent by the same factors that confine the ozone hole to high latitudes in winter). The stratospheric sulfate aerosol layer reflects solar radiation and increases the planetary albedo, thereby cooling the surface and possibly altering the climate. Major volcanic eruptions, which increase the sulfate aerosol burden by a factor of 100 or more, may cause significant global climate anomalies. Sulfate aerosols might also be capable of activating stratospheric chlorine reservoirs on a global scale (unlike PCSs, which represent a localized polar winter phenomenon), although existing evidence suggests relatively minor perturbations in chlorine chemistry. Nevertheless, if

  17. Heterogeneous Uptake of HO2 Radicals onto Submicron Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Matthews, P. S.; George, I. J.; Brooks, B.; Whalley, L. K.; Baeza-Romero, M. T.; Heard, D. E.

    2012-12-01

    OH and HO2 (HOx) radicals are closely coupled and OH is responsible for the majority of the oxidation in the troposphere and controls the concentrations of many trace species. Therefore, it is important to be able to accurately predict HOx concentrations. However, some field measurement studies have reported significantly lower HO2 radical concentrations than calculated by constrained box models using detailed chemical mechanisms. Although the inclusion of halogen chemistry into the mechanisms can explain much of the differences in the marine boundary layer (MBL) (1,2), HO2 uptake by aerosols has been suggested as a possible sink in the MBL (2), the Arctic troposphere (3) and the upper troposphere (4). There have been very few laboratory studies (5,6) on HO2 uptake by aerosols and the rates and mechanism is still uncertain. The HO2 uptake coefficients were measured for a variety of atmospherically relevant inorganic and organic aerosols. The measurements were performed using an aerosol flow tube combined with a Fluorescence Assay by Gas Expansion (FAGE) detector. The sensitive FAGE cell allowed low HO2 concentrations (108-109 molecule cm-3) to be injected into the flow tube using a moveable injector. By moving the injector along the flow tube, position dependent HO2 decays were able to be recorded which when plotted against the total aerosol surface area allowed an uptake coefficient to be obtained. The aerosols were generated using an atomiser or by homogeneous nucleation and the total aerosol surface area was measured using a Scanning Mobility Particle Sizer. The HO2 uptake coefficient (γ) was measured at room temperature for dry inorganic salts and dry organics (γ< 0.004), wet inorganic salts and wet organics (γ= 0.002-0.005), wet copper doped ammonium sulfate aerosols (γ= 0.28± 0.05) and ammonium sulfate aerosols doped with different molar amounts of iron (γ= 0.003-0.06). The pH dependence of the HO2 uptake coefficient was investigated, however no

  18. Aerosol Charging by Ion Attachment and Electrical Conductivity in the Lower Atmosphere of Mars

    NASA Astrophysics Data System (ADS)

    Tripathi, S. N.; Michael, M.

    2007-12-01

    Aerosol in the atmosphere of Mars is a topic of considerable interest since their effect on the climate has been recognized. The aerosols interact with both visible and infrared radiation and modify atmospheric heating rates which are responsible for the atmospheric circulation, dust storms etc. In the present work, the charging of aerosols and the conductivity of the lower atmosphere of Mars during the day and night-time are calculated. Galactic cosmic rays are the dominant ionizing process in the lower atmosphere producing molecular ions and ion clusters. These ion clusters get attached to the aerosols and charging occurs during the night-time. Solar UV photons are an additional ionizing agent during the day-time. Solar photons of energy less than 6 eV reach the surface of Mars as those with energies greater than 6 eV are absorbed by the atmospheric molecules before they reach the lower atmosphere. Those photons, which reach the lower atmosphere, ionize the aerosols as the ionization potential of most of the aerosols is less than 6 eV and produce electrons. Aerosols become charged by the attachment of ions and electrons during the day-time. The ion-aerosol and electron-aerosol attachment coefficients are calculated. The neutral atmospheric properties required to calculate the aerosol charging and the conductivity are obtained from Magalhaes et al. (1999). The aerosols have a concentration and effective radius of 2.26 cm-3 and 1.9 mm, respectively, at the surface. The charge distribution of aerosols is obtained by the simultaneous solution of the ion-electron-aerosol charge balance equations. Both the steady state and time dependent concentration of charged aerosols are calculated. It was observed that about 80% of the aerosols close to the surface become charged during the night-time (Michael et al., 2007). In addition to ions, electrons are also present during the day-time. More charging occurs and most of the aerosols become charged during the day-time. The

  19. Atmospheric Feedbacks, Aerosol Forcings, and Tropical Precipitation Shifts

    NASA Astrophysics Data System (ADS)

    Hwang, Y.; Frierson, D. M.; Kang, S.

    2011-12-01

    It is well known that variations in climate sensitivity among global climate models (GCMs) are largely attributable to differences in atmospheric feedbacks that affect the top of the atmosphere radiation budget. Here, we demonstrate how the hemispheric asymmetry of these feedbacks influence cross-equatorial energy transport, and thus explain differences in models projection of tropical precipitation. The framework we use is based on fundamental energetic constraints of the system: since both moisture transports and energy transports within the deep tropical atmosphere are governed by the Hadley circulation, a southward shift of the intertropical conversion zone (ITCZ) is associated with a northward transport of moist static energy. This situation is typically associated with enhanced heating of the Southern Hemisphere, often due to hemispheric differences in aerosols, clouds, water vapor, surface albedo changes. We find that the ITCZ appears to shift southward in the 20th century in both rain gauges (GHCN) and reanalysis (20CRP) data. Most of the global climate models (GCMs) in the CMIP3 archive reproduce the direction of this shift. However, they all underestimate the shift with greatly varying degree. Using the energetic framework, we conclude that (1) aerosol cooling in the northern hemisphere shifts the ITCZ south in all of the GCMs (2) differences in feedbacks (particularly cloud feedbacks) in GCMs are responsible for the spread in the ITCZ shifts. This result emphasizes that biases in feedbacks and forcings will not only affect global mean temperature, but will also influence climate in various latitudes through energy transport.

  20. Characterising the influence of atmospheric mixing state on Urban Heat Island Intensity using Radon-222

    NASA Astrophysics Data System (ADS)

    Chambers, Scott D.; Podstawczyńska, Agnieszka; Williams, Alastair G.; Pawlak, Włodzimierz

    2016-12-01

    Characterisation of the effects of varying atmospheric mixing states (stability) in urban climate studies has historically been hampered by problems associated with the complexity of the urban environment, representativity of measurement techniques, and the logistical and financial burdens of maintaining multiple long-term comprehensive measurement sites. These shortcomings, together with a lack of a consistent measurement approach, have limited our ability to understand the physical processes contributing to the urban heat island effect. In this study, we analyse 4 years of continuous hourly near-surface meteorological and atmospheric radon data from an urban-rural site pair in central Poland. A recently-developed radon-based stability classification technique, previously developed for urban pollution characterisation, is employed to characterise the Urban Heat Island Intensity (UHII) and other climatic factors over the full diurnal cycle by season and atmospheric mixing state. By characterising the UHII over a range of atmospheric mixing states in a statistically robust way, this technique provides an effective tool for assessing the efficacy of mitigation measures for urban climate effects in a consistent way over timescales of years to decades. The consistency of approach, ease of application, and unprecedented clarity of findings, provide a strong argument for atmospheric radon observations to be included as part of the 'standard measurement suite' for urban climate monitoring networks for non-coastal cities.

  1. Characterizations of atmospheric fungal aerosol in Beijing, China

    NASA Astrophysics Data System (ADS)

    Liang, Linlin; Engling, Guenter; He, Kebin; Du, Zhenyu

    2013-04-01

    Fungal aerosols constitute the most abundant fraction of biological aerosols in the atmosphere, influencing human health, the biosphere, atmospheric chemistry and climate. However, the total abundance of fungal spores in the atmosphere is still poorly understood and quantified. PM10 and PM2.5 samples were collected by high volume samplers simultaneously at a rural site (MY) and an urban site (THU) in Beijing, China. Various carbohydrates were quantified by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), including the sugar alcohols mannitol and arabitol, proposed as molecular tracers for fungal aerosol. The annual average concentrations of arabitol in PM2.5 and PM10 at the THU site were 7.4±9.4 ng/m3 and 10.3±9.5 ng/m3, and the respective mannitol concentrations were 21.0±20.4 ng/m3 and 31.9±26.9 ng/m3. Compared to PM10, the monthly average concentrations of arabitol and mannitol in PM2.5 did not vary significantly and were present at nearly consistent levels in the different seasons. Moreover, during summer and autumn higher arabitol and mannitol levels than during spring and winter were observed in coarse particles, probably due to different dominant sources of fungal spores in different seasons. In the dry period (i.e., winter and spring) in Beijing, probably only the suspension from exposed surfaces, (e.g., soil resuspension, transported dust, etc.) can be regarded as the main sources for fungal aerosols. On the other hand, in summer and autumn, fungal spores in the atmosphere can be derived from more complex sources, including plants, vegetation decomposition and agricultural activity, such as ploughing; these fungal spore sources may contribute more to coarse PM. Mannitol and arabitol correlated well with each other, both in PM10 (R2 = 0.71) and PM2.5 (R2 = 0.81). Although fungal spore levels at rural sites were consistently higher than those at urban sites in other studies, the findings in our study were

  2. Automatic identification of sources and trajectories of atmospheric Saharan dust aerosols with Latent Gaussian Models

    NASA Astrophysics Data System (ADS)

    Garbe, Christoph; Bachl, Fabian

    2013-04-01

    Dust transported from the Sahara across the ocean has a high impact on radiation fluxes and marine nutrient cycles. Significant progress has been made in characterising Saharan dust properties (Formenti et al., 2011) and its radiative effects through the 'SAharan Mineral dUst experiMent' (SAMUM) (Ansmann et al., 2011). While the models simulating Saharan dust transport processes have been considerably improved in recent years, it is still an open question which meteorological processes and surface characteristics are mainly responsible for dust transported to the Sub-Tropical Atlantic (Schepanski et al., 2009; Tegen et al., 2012). Currently, there exists a large discrepancy between modelled dust emission events and those observed from satellites. In this contribution we present an approach for classifying and tracking dust plumes based on a Bayesian hierarchical model. Recent developments in computational statistics known as Integrated Nested Laplace Approximations (INLA) have paved the way for efficient inference in a respective subclass, the Generalized Linear Model (GLM) (Rue et al., 2009). We present the results of our approach based on data from the SIVIRI instrument on board the Meteosat Second Generation (MSG) satellite. We demonstrate the accuracy for automatically detecting sources of dust and aerosol concentrations in the atmosphere. The trajectories of aerosols are also computed very efficiently. In our framework, we automatically identify optimal parameters for the computation of atmospheric aerosol motion. The applicability of our approach to a wide range of conditions will be discussed, as well as the ground truthing of our results and future directions in this field of research.

  3. Atmospheric aerosol brown carbon in the high Himalayas

    NASA Astrophysics Data System (ADS)

    Kirillova, Elena; Decesari, Stefano; Marinoni, Angela; Bonasoni, Paolo; Vuillermoz, Elisa; Facchini, M. Cristina; Fuzzi, Sandro

    2016-04-01

    Anthropogenic light-absorbing atmospheric aerosol can reach very high concentrations in the planetary boundary layer in South-East Asia ("brown clouds"), affecting atmospheric transparency and generating spatial gradients of temperature over land with a possible impact on atmospheric dynamics and monsoon circulation. Besides black carbon (BC), an important light-absorbing component of anthropogenic aerosols is the organic carbon component known as 'brown carbon' (BrC). In this research, we provided first measurements of atmospheric aerosol BrC in the high Himalayas during different seasons. Aerosol sampling was conducted at the GAW-WMO Global station "Nepal Climate Observatory-Pyramid" (NCO-P) located in the high Khumbu valley at 5079 m a.s.l. in the foothills of Mt. Everest. PM10 aerosol samples were collected from July 2013 to November 2014. The sampling strategy was set up in order to discriminate the daytime valley breeze bringing polluted air masses up to the observatory and free tropospheric air during nighttime. Water-soluble BrC (WS-BrC) and methanol-soluble BrC (MeS-BrC) were extracted and analyzed using a UV/VIS spectrophotometer equipped with a 50 cm liquid waveguide capillary cell. In the polluted air masses, the highest levels of the BrC light absorption coefficient at 365 nm (babs365) were observed during the pre-monsoon season (1.83±1.46 Mm-1 for WS-BrC and 2.86±2.49 Mm-1 for MeS-BrC) and the lowest during the monsoon season (0.21±0.22 Mm-1 for WS-BrC and 0.32±0.29 Mm-1 for MeS-BrC). The pre-monsoon season is the most frequently influenced by a strong atmospheric brown cloud (ABC) transport to NCO-P due to increased convection and mixing layer height over South Asia combined with the highest up-valley wind speed and the increase of the emissions from open fires due to the agricultural practice along the Himalayas foothills and the Indo-Gangetic Plain. In contrast, the monsoon season is characterized by a weakened valley wind regime and an

  4. Organic Aerosols in Rural and Remote Atmospheric Environments: Insights from Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Jimenez, J.; Ulbrich, I.; Dunlea, E.; Decarlo, P.; Huffman, A.; Allan, J.; Coe, H.; Alfarra, R.; Canagaratna, M.; Onasch, T.; Jayne, J.; Worsnop, D.; Takami, A.; Miyoshi, T.; Shimono, A.; Hatakeyama, S.; Weimer, S.; Demerjian, K.; Drewnick, F.; Schneider, J.; Middlebrook, A.; Bahreini, R.; Cotrell, L.; Griffin, R.; Leaitch, R.; Li, S.; Hayden, K.; Rautiainen, J.

    2006-12-01

    Organic matter usually accounts for a large fraction of the fine particle mass in rural and remote atmospheres. However, little is known about the sources and properties of this material. Here we report findings on the characteristics and the major types of organic aerosols (OA) in urban downwind, high elevation, forested, and marine atmospheres based on analyses of more than 20 highly time resolved AMS datasets sampled from various locations in the mid-latitude Northern Hemisphere. Organic aerosol components are extracted from these datasets using a custom multiple component mass spectral analysis technique and the Positive Matrix Factorization (PMF) method. These components are evaluated according to their extracted mass spectra and correlations to aerosol species, such as sulfate, nitrate, and elemental carbon, and gas-phase tracer compounds, such as CO and NOx. We have identified a hydrocarbon-like organic aerosol (HOA) component similar in mass spectra to the hydrocarbon substances observed at urban locations. We have also identified several oxygenated OA (OOA) components that show different fragmentation patterns and oxygen to carbon ratios in their mass spectra. Two OOA components a highly oxygenated that has mass spectrum resembling that of fulvic acid (a model compound representative for highly processed/oxidized organics in the environment) and a less oxygenated OOA component, whose spectrum is dominated with ions that are mainly associated with carbonyls and alcohols, are very frequently observed at various rural/remote sites. The oxygenated OOA component is more prevalent at downwind sites influenced by urban transport and the less oxygenated shows correlation to biogenic chamber OA at some locations. Compared to the total OOA concentration, HOA is generally very small and accounts for < 10% of the total OA mass at rural/remote sites. The comparisons between the concentrations of HOA and primary OA (POA) that would be predicted according to inert

  5. Measurement of the nucleation of atmospheric aerosol particles.

    PubMed

    Kulmala, Markku; Petäjä, Tuukka; Nieminen, Tuomo; Sipilä, Mikko; Manninen, Hanna E; Lehtipalo, Katrianne; Dal Maso, Miikka; Aalto, Pasi P; Junninen, Heikki; Paasonen, Pauli; Riipinen, Ilona; Lehtinen, Kari E J; Laaksonen, Ari; Kerminen, Veli-Matti

    2012-09-01

    The formation of new atmospheric aerosol particles and their subsequent growth have been observed frequently at various locations all over the world. The atmospheric nucleation rate (or formation rate) and growth rate (GR) are key parameters to characterize the phenomenon. Recent progress in measurement techniques enables us to measure atmospheric nucleation at the size (mobility diameter) of 1.5 (±0.4) nm. The detection limit has decreased from 3 to 1 nm within the past 10 years. In this protocol, we describe the procedures for identifying new-particle-formation (NPF) events, and for determining the nucleation, formation and growth rates during such events under atmospheric conditions. We describe the present instrumentation, best practices and other tools used to investigate atmospheric nucleation and NPF at a certain mobility diameter (1.5, 2.0 or 3.0 nm). The key instruments comprise devices capable of measuring the number concentration of the formed nanoparticles and their size, such as a suite of modern condensation particle counters (CPCs) and air ion spectrometers, and devices for characterizing the pre-existing particle number concentration distribution, such as a differential mobility particle sizer (DMPS). We also discuss the reliability of the methods used and requirements for proper measurements and data analysis. The time scale for realizing this procedure is 1 year.

  6. Atmospheric budget of different elements in aerosol particles over Hungary

    NASA Astrophysics Data System (ADS)

    Molnár, A.; Mészáros, E.; Polyák, K.; Borbély-Kiss, I.; Koltay, E.; Szabó, Gy.; Horváth, Zs.

    The aim of this paper is to present the budget of seven elements (Cd, Cu, Mn, Ni, Pb, V and Zn) in the atmospheric aerosol over Hungary. The dry deposition is estimated on the basis of concentration and size distribution measurements and on dry deposition velocities available in the literature. The dry deposition velocity of two elements is obtained by transport model calculations. Wet deposition rates are determined by analyzing precipitation samples. The emissions of different elements necessary for budgeting are calculated by using statistical data on fossil fuel and gasoline burning, metallurgy, cement industry and waste incineration as well as on emission factors given by Pacyna (1984, Atmospheric Environment18, 41-50). It is found that the country is a net source for elements produced mostly by fossil fuel combustion while it is a net sink for elements released during industrial processes and automotive transport.

  7. Atmospheric Condensational Properties of Ultrafine Chain and Fractal Aerosol Particles

    NASA Technical Reports Server (NTRS)

    Marlow, William H.

    1997-01-01

    The purpose for the research sponsored by this grant was to lay the foundations for qualitative understanding and quantitative description of the equilibrium vapor pressure of water vapor over the irregularly shaped, carbonaceous particles that are present in the atmosphere. This work apparently was the first systematic treatment of the subject. Research was conducted in two complementary components: 1. Calculations were performed of the equilibrium vapor pressure of water over particles comprised of aggregates of spheres in the 50-200 nm radius range. The purposes of this work were two-fold. First, since no systematic treatment of this subject had previously been conducted, its availability would be directly useful for quantitative treatment for a limited range of atmospheric aerosols. Second, it would provide qualitative indications of the effects of highly irregular particle shape on equilibrium vapor pressure of aggregates comprised of smaller spheres.

  8. Laboratory simulations of Titan's atmosphere: organic gases and aerosols.

    PubMed

    Cabane, M; Chassefière, E

    1995-01-01

    Titan, the main satellite of Saturn, has been observed by remote sensing for many years, both from interplanetary probes (Pioneer and Voyager's flybys) and from the Earth. Its N2 atmosphere, containing a small fraction of CH4 (approximately 2%), with T approximately 90 K and P approximately 1.5 bar at the ground level, is irradiated by solar UV photons and deeply bombarded by energetic particles, i.e. Saturn mangetospheric electrons and protons, interplanetary electrons and cosmic rays. The resulting energy deposition, which takes place mainly below 1000 km, initiates chemical reactions which yield gaseous hydrocarbons and nitriles and, through polymerisation processes, solid aerosol particles which grow by coagulation and settle down to the ground. At the present time, photochemical models strongly require the results of specific laboratory studies. Chemical rate constants are not well known at low temperatures, charged-particle-induced reactions are difficult to model and laboratory simulations of atmospheric processes are therefore of great interest. Moreover, the synthesis of organic compounds which have not been detected to date provides valuable information for future observations. The origin and chemical composition of aerosols depend on the nature of chemical and energy sources. Their production from gaseous species may be monitored in laboratory chambers and their optical or microphysical properties compared to those deduced from the observations of Titan's atmosphere. The development of simulation chambers of Titan's extreme conditions is necessary for a better understanding of past and future observations. Space probes will sound Titan's atmosphere by remote sensing and in situ analysis in the near future (Cassini-Huygens mission). It appears necessary, as a preliminary step to test on-board experiments in such chambers, and as a final step, when new space data have been acquired, to use them for more general scientific purposes.

  9. Modelling aerosol processes related to the atmospheric dispersion of sarin.

    PubMed

    Kukkonen, J; Riikonen, K; Nikmo, J; Jäppinen, A; Nieminen, K

    2001-08-17

    We have developed mathematical models for evaluating the atmospheric dispersion of selected chemical warfare agents (CWA), including the evaporation and settling of contaminant liquid droplets. The models and numerical results presented may be utilised for designing protection and control measures against the conceivable use of CWA's. The model AERCLOUD (AERosol CLOUD) was extended to treat two nerve agents, sarin and VX, and the mustard agent. This model evaluates the thermodynamical evolution of a five-component aerosol mixture, consisting of two-component droplets together with the surrounding three-component gas. We have performed numerical computations with this model on the evaporation and settling of airborne sarin droplets in characteristic dispersal and atmospheric conditions. In particular, we have evaluated the maximum radii (r(M)) of a totally evaporating droplet, in terms of the ambient temperature and contaminant vapour concentration. The radii r(M) range from approximately 15-80 microm for sarin droplets for the selected ambient conditions and initial heights. We have also evaluated deposition fractions in terms of the initial droplet size.

  10. Heterogeneous atmospheric reactions - Sulfuric acid aerosols as tropospheric sinks

    NASA Technical Reports Server (NTRS)

    Baldwin, A. C.; Golden, D. M.

    1979-01-01

    The reaction probabilities of various atmospheric species incident on a bulk sulfuric acid surface are measured in order to determine the role of sulfuric acid aerosols as pollutant sinks. Reaction products and unreacted starting materials leaving a Knudsen cell flow reactor after collision at 300 K with a H2SO4 surface or a soot surface were detected by mass spectrometry. Significant collision reaction probabilities are observed on a H2SO4 surface for H2O2, HNO3, HO2NO2, ClONO2, N2O5, H2O and NH3, and on soot for NH3. Estimates of the contribution of heterogeneous reactions to pollutant removal under atmospheric conditions indicate that while aerosol removal in the stratosphere is insignificant (loss rate constants approximately 10 to the -10th/sec), heterogeneous reactions may be the dominant loss process for several tropospheric species (loss rate constant approximately 10 to the -5th/sec, comparable to photolysis rate constants).

  11. A Search for Correlations Between Four Different Atmospheric Aerosol Measurement Systems Atop Rattlesnake Mountain, Washington

    NASA Astrophysics Data System (ADS)

    Milbrath, Brian

    2004-05-01

    Accurate atmospheric aerosol transport measurements are important to international nuclear test monitoring, emergency response, health and ecosystem toxicology, and climate change. An International Monitoring System (IMS) is being established which will include a suite of aerosol radionuclide sensors. To explore the possibility of using the IMS sites to improve the understanding of global atmospheric aerosol transport, four state-of-the-art aerosol measurement systems were placed atop Rattlesnake Mountain at Pacific Northwest National Laboratory. The Radionuclide Aerosol Sampler/Analyzer measures radionuclide concentration via gamma-ray spectroscopy. The Cascade Impactor Beam Analyzer Technique measures 30 elements in three aerosol sizes using PNNLâ's Ion Beams Materials Analysis Laboratory. The Tapered Element Oscillating Microbalance provides time-averaged aerosol mass concentrations for a range of sizes. The Multi-Filter Rotating Shadowband Radiometer measures the solar irradiance to derive an aerosol optical depth. Results and correlations from the four different detectors will be presented.

  12. Optical and Hygroscopic Studies of Aerosols In Simulated Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Hasenkopf, Christa A.

    2011-08-01

    Basic characteristics of the early Earth climate, the only known environment in the Universe in which life has been known to emerge and thrive, remain a mystery. In particular, little is understood about the Earth's atmosphere 2.8 billion years ago. From climate models and laboratory studies, it is postulated that an organic haze, much like that found on Saturn's largest moon Titan, covered the early Earth. This haze, generated from photolysis of carbon dioxide (CO2) and methane (CH4), may have had profound climatic consequences. Climate models of the early Earth that include this haze have had to rely upon optical properties of a Titan laboratory analog. Titan haze, though thought to be similar, is formed from a different combination of precursor gases and by different energy sources than early Earth haze. This thesis examines the direct and indirect radiative effects of aerosol on early Earth climate by studying the optical and hygroscopic properties of a laboratory analog. A Titan analog is studied for comparison and to better understand spacecraft-retrieved haze chemical and optical properties from Titan. The properties of the laboratory analogs, generated in a flowing reactor cell with a continuum ultraviolet (UV) light source, were primarily measured using cavity ringdown aerosol extinction spectroscopy and UV-visible (UV-Vis) transmission spectroscopy. We find that the optical properties of our early Earth analog are significantly different than those of the Titan analog from Khare et al. (1984). In both the UV and visible, when modeled as fractals, particles with the optical properties of the early Earth analog have approximately 30% larger extinction efficiencies than particles with Khare et al. (1984) values. This result implies our early Earth haze analog would provide a more efficient UV shield and have a stronger antigreenhouse effect than the Khare et al. (1984) Titan analog. Our Titan analog has significantly smaller imaginary refractive index values

  13. Modeling the aerosols in the atmosphere of Titan

    NASA Astrophysics Data System (ADS)

    Thomas-Osip, Joanna Elizabeth

    2001-09-01

    A combination of laboratory experiments, theoretical modeling, and spacecraft in situ observations is employed to characterize the aerosols in the atmosphere of Titan. The scattering properties of model aerosols were measured using the Microwave Analog Light Scattering Facility at the University of Florida and complemented with theoretical modeling of single scattering characteristics and radiative transfer in Titan's atmosphere. This study compares these modeling results with photopolarimetric observations made over a range of phase angles by the Pioneer 11 and Voyagers 1 and 2 spacecraft approximately 20 years ago. Important results of this work include a survey of the scattering properties of different particle shapes necessary to accurately interpret these observations without introducing non-physical assumptions about the particles or requiring additional free parameters to the radiative transfer models. Previous studies use calculation methods which, due to computing memory and processing time requirements, a priori exclude much of the phase space that the microwave analog laboratory is ideal for exploring. The goal of the present work, to directly constrain aerosol physical characteristics, is addressed by studying in a consistent manner how a variety of particle morphologies affect polarization and intensity measurements of Titan's atmosphere. Single liquid drops are modeled using spheres for which scattering patterns can be easily calculated with Mie theory. Cubes are used as a representation of solids with sharp edges due to fragmentation. More complex particle morphologies are modeled as aggregates that are likely formed by collisions between semi-liquid spheres that stick together instead of merging. Radiative transfer calculations for model atmospheres containing these particles are constrained by direct comparison to in situ spacecraft observations. Based on these comparisons, many model morphologies are excluded from further consideration and the

  14. The impact of atmospheric aerosols on trace metal chemistry in open ocean surface seawater. 3. Lead

    NASA Astrophysics Data System (ADS)

    Maring, H. B.; Duce, R. A.

    1990-04-01

    Atmospheric aerosols collected at Enewetak Atoll in the tropical North Pacific were exposed to seawater in laboratory experiments to assess the impact of atmospheric aerosols on lead chemistry in surface seawater. The net atmospheric flux of soluble lead to the ocean is between 16 and 32 pmol cm-2 yr-1 at Enewetak. The stable lead isotopic composition of soluble aerosol lead indicates that it is of anthropogenic origin. Anthropogenic aerosol lead from Central and North America appears to be less soluble and/or to dissolve less rapidly than that from Asia. Dissolved organic matter and possibly lower pH appear to increase the nonaluminosilicate aerosol lead solubility and/or dissolution rate. The isotopic composition of lead in air, seawater and dry deposition suggests that after deposition in the ocean, nonaluminosilicate paniculate lead can be reinjected into the atmosphere during sea salt aerosol production.

  15. Dynamical characteristics of atmospheric aerosols over IG region

    NASA Astrophysics Data System (ADS)

    Sharma, Manish; Singh, Ramesh P.; Kumar, Rajesh

    2016-05-01

    The dynamical characteristics of atmospheric aerosols over the Indo-Gangetic (IG) region are primarily dependent on the geographical settings and meteorological conditions. Detailed analysis of multi satellite data and ground observations have been carried out over three different cities i.e. Kanpur, Greater Noida and Amritsar during 2010-2013. Level-3 Moderate Resolution Imaging Spectroradiometer (MODIS) terra daily global grid product with spatial resolution of 1° × 1° shows the mean AOD at 500 nm wavelength value of 0.73, 0.70 and 0.67 with the standard deviation of 0.43, 0.39 and 0.36 respectively over Amritsar, Greater Noida and Kanpur. Our detailed analysis shows characteristic behavior of aerosols from west to east in the IG region depending upon the proximity of desert regions of Arabia. We have observed large influx of dusts from the Thar desert and Arabia peninsula during pre-monsoon season (April-June), highly affecting Amritsar which is close to the desert region.

  16. Compact Efficient Lidar Receiver for Measuring Atmospheric Aerosols

    NASA Technical Reports Server (NTRS)

    Gili, Christopher; De Young, Russell

    2006-01-01

    A small, light weight, and efficient aerosol lidar receiver was constructed and tested. Weight and space savings were realized by using rigid optic tubes and mounting cubes to package the steering optics and detectors in a compact assembly. The receiver had a 1064nm channel using an APD detector. The 532nm channel was split (90/10) into an analog channel (90%) and a photon counting channel (10%). The efficiency of the 1064nm channel with optical filter was 44.0%. The efficiency of the analog 532nm channel was 61.4% with the optical filter, and the efficiency of the 532nm photon counting channel was 7.6% with the optical filter. The results of the atmospheric tests show that the detectors were able to consistently return accurate results. The lidar receiver was able to detect distinct cloud layers, and the lidar returns also agreed across the different detectors. The use of a light weight fiber-coupled telescope reduced weight and allowed great latitude in detector assembly positioning due to the flexibility enabled by the use of fiber optics. The receiver is now ready to be deployed for aircraft or ground based aerosol lidar measurements.

  17. Aerosol Retrieval and Atmospheric Correction Algorithms for EPIC

    NASA Technical Reports Server (NTRS)

    Wang, Yujie; Lyapustin, Alexei; Marshak, Alexander; Korkin, Sergey; Herman, Jay

    2011-01-01

    EPIC is a multi-spectral imager onboard planned Deep Space Climate ObserVatoRy (DSCOVR) designed for observations of the full illuminated disk of the Earth with high temporal and coarse spatial resolution (10 km) from Lagrangian L1 point. During the course of the day, EPIC will view the same Earth surface area in the full range of solar and view zenith angles at equator with fixed scattering angle near the backscattering direction. This talk will describe a new aerosol retrieval/atmospheric correction algorithm developed for EPIC and tested with EPIC Simulator data. This algorithm uses the time series approach and consists of two stages: the first stage is designed to periodically re-initialize the surface spectral bidirectional reflectance (BRF) on stable low AOD days. Such days can be selected based on the same measured reflectance between the morning and afternoon reciprocal view geometries of EPIC. On the second stage, the algorithm will monitor the diurnal cycle of aerosol optical depth and fine mode fraction based on the known spectral surface BRF. Testing of the developed algorithm with simulated EPIC data over continental USA showed a good accuracy of AOD retrievals (10-20%) except over very bright surfaces.

  18. Easy Aerosol - Robust and non-robust circulation responses to aerosol radiative forcing in comprehensive atmosphere models

    NASA Astrophysics Data System (ADS)

    Voigt, Aiko; Bony, Sandrine; Stevens, Bjorn; Boucher, Olivier; Medeiros, Brian; Pincus, Robert; Wang, Zhili; Zhang, Kai; Lewinschal, Anna; Bellouin, Nicolas; Yang, Young-Min

    2015-04-01

    A number of recent studies illustrated the potential of aerosols to change the large-scale atmospheric circulation and precipitation patterns. It remains unclear, however, to what extent the proposed aerosol-induced changes reflect robust model behavior or are affected by uncertainties in the models' treatment of parametrized physical processes, such as those related to clouds. "Easy Aerosol", a model-intercomparison project organized within the Grand Challenge on Clouds, Circulation and Climate Sensitivity of the World Climate Research Programme, addresses this question by subjecting a suite of comprehensive atmosphere general circulation models with prescribed sea-surface temperatures (SSTs) to the same set of idealized "easy" aerosol perturbations. This contribution discusses the aerosol perturbations as well as their impact on the model's precipitation and surface winds. The aerosol perturbations are designed based on a global aerosol climatology and mimic the gravest mode of the anthropogenic aerosol. Specifically, the meridional and zonal distributions of total aerosol optical depth are approximated by a superposition of Gaussian plumes; the vertical distribution is taken as constant within the lowest 1250m of the atmosphere followed by an exponential decay with height above. The aerosol both scatters and absorbs shortwave radiation, but in order to focus on direct radiative effects aerosol-cloud interactions are omitted. Each model contributes seven simulations. A clean control case with no aerosol-radiative effects at all is compared to six perturbed simulations with differing aerosol loading, zonal aerosol distributions, and SSTs. To estimate the role of natural variability, one of the models, MPI-ESM, contributes a 5-member ensemble for each simulation. If the observed SSTs from years 1979-2005 are prescribed, the aerosol leads to a local depression of precipitation at the Northern Hemisphere center of the aerosol and a northward shift of the

  19. Visible and infrared extinction of atmospheric aerosol in the marine and coastal environment.

    PubMed

    Kaloshin, Gennady A

    2011-05-10

    The microphysical model Marine Aerosol Extinction Profiles (MaexPro) for surface layer marine and coastal atmospheric aerosols, which is based on long-term observations of size distributions for 0.01-100 μm particles, is presented. The fundamental feature of the model is a parameterization of amplitudes and widths for aerosol modes of the aerosol size distribution function (ASDF) as functions of fetch and wind speed. The shape of the ASDF and its dependence on meteorological parameters, altitudes above the sea level (H), fetch (X), wind speed (U), and relative humidity is investigated. The model is primarily to characterize aerosols for the near-surface layer (within 25 m). The model is also applicable to higher altitudes within the atmospheric boundary layer, where the change in the vertical profile of aerosol is not very large. In this case, it is only valid for "clean" marine environments, in the absence of air pollution or any other major sources of continental aerosols, such desert dust or smoke from biomass burning. The spectral profiles of the aerosol extinction coefficients calculated by MaexPro are in good agreement with observational data and the numerical results obtained by the well-known Navy Aerosol Model and Advanced Navy Aerosol Model codes. Moreover, MaexPro was found to be an accurate and reliable instrument for investigation of the optical properties of atmospheric aerosols.

  20. Nucleation and growth processes of atmospheric aerosols and clouds

    SciTech Connect

    Schwartz, S.E.; McGraw, R.L.

    1995-11-01

    This project seeks to gain enhanced understanding of the rate of formation and growth of new particles and of cloud droplets as a function of pertinent controlling atmospheric variables, thereby permitting accurate representation of these processes in climate models. Aerosol size distributions are shaped by complex nucleation and growth and mixing processes that are difficult to represent in models, due to the need to accurately represent the evaporation/growth kinetics for each of the billions of discrete cluster sizes in the growth sequence, ranging from molecular clusters to particles of radius of several tenths of a micrometer or greater. A potentially very powerful means of solving this problem may be given by the method of moments (MOM), which tracks the time dependence of just the lower-order radial moments of the size distribution without requiring knowledge of the distribution itself.

  1. Aerosol Optical Thickness Derived From Atmospheric Transmittance Using Spectroradiometer Measurements

    NASA Astrophysics Data System (ADS)

    Hwee San, Hslim; Matjafri, M. Z.; Abdullah, Abdul K.; Chow Jeng, C. J.

    section The objective of this study was to test the feasibility of hand held spectroradiometer measurements for the retrieval AOT values Twenty-six stations were chosen randomly around Penang Island and the atmospheric transmittance measurements were collected using a handheld spectroradiometer The corresponding PM10 concentrations were measured using a portable DustTrak Aerosol Monitor 8520 simultaneously with the measurements of the transmittance data The AOT values were calculated using the Beer-Lambert-Bouguer law Linear relationship was found between AOT and PM10 values in this study Finally a PM10 map was created using Kriging interpolation technique The result of the study showed the potential of a spectroradiometer data for the retrieval of AOT and PM10 to provide the air pollution information

  2. Small molecules as tracers in atmospheric secondary organic aerosol

    NASA Astrophysics Data System (ADS)

    Yu, Ge

    Secondary organic aerosol (SOA), formed from in-air oxidation of volatile organic compounds, greatly affects human health and climate. Although substantial research has been devoted to SOA formation and evolution, the modeled and lab-generated SOA are still low in mass and degree of oxidation compared to ambient measurements. In order to compensate for these discrepancies, the aqueous processing pathway has been brought to attention. The atmospheric waters serve as aqueous reaction media for dissolved organics to undergo further oxidation, oligomerization, or other functionalization reactions, which decreases the vapor pressure while increasing the oxidation state of carbon atoms. Field evidence for aqueous processing requires the identification of tracer products such as organosulfates. We synthesized the standards for two organosulfates, glycolic acid sulfate and lactic acid sulfate, in order to measure their aerosol-state concentration from five distinct locations via filter samples. The water-extracted filter samples were analyzed by LC-MS. Lactic acid sulfate and glycolic acid sulfate were detected in urban locations in the United States, Mexico City, and Pakistan with varied concentrations, indicating their potential as tracers. We studied the aqueous processing reaction between glyoxal and nitrogen-containing species such as ammonium and amines exclusively by NMR spectrometry. The reaction products formic acid and several imidazoles along with the quantified kinetics were reported. The brown carbon generated from these reactions were quantified optically by UV-Vis spectroscopy. The organic-phase reaction between oxygen molecule and alkenes photosensitized by alpha-dicarbonyls were studied in the same manner. We observed the fast kinetics transferring alkenes to epoxides under simulated sunlight. Statistical estimations indicate a very effective conversion of aerosol-phase alkenes to epoxides, potentially forming organosulfates in a deliquescence event and

  3. MATRIX (Multiconfiguration Aerosol TRacker of mIXing state): an aerosol microphysical module for global atmospheric models

    NASA Astrophysics Data System (ADS)

    Bauer, S. E.; Wright, D. L.; Koch, D.; Lewis, E. R.; McGraw, R.; Chang, L.-S.; Schwartz, S. E.; Ruedy, R.

    2008-10-01

    A new aerosol microphysical module MATRIX, the Multiconfiguration Aerosol TRacker of mIXing state, and its application in the Goddard Institute for Space Studies (GISS) climate model (ModelE) are described. This module, which is based on the quadrature method of moments (QMOM), represents nucleation, condensation, coagulation, internal and external mixing, and cloud-drop activation and provides aerosol particle mass and number concentration and particle size information for up to 16 mixed-mode aerosol populations. Internal and external mixing among aerosol components sulfate, nitrate, ammonium, carbonaceous aerosols, dust and sea-salt particles are represented. The solubility of each aerosol population, which is explicitly calculated based on its soluble and insoluble components, enables calculation of the dependence of cloud drop activation on the microphysical characterization of multiple soluble aerosol populations. A detailed model description and results of box-model simulations of various aerosol population configurations are presented. The box model experiments demonstrate the dependence of cloud activating aerosol number concentration on the aerosol population configuration; comparisons to sectional models are quite favorable. MATRIX is incorporated into the GISS climate model and simulations are carried out primarily to assess its performance/efficiency for global-scale atmospheric model application. Simulation results were compared with aircraft and station measurements of aerosol mass and number concentration and particle size to assess the ability of the new method to yield data suitable for such comparison. The model accurately captures the observed size distributions in the Aitken and accumulation modes up to particle diameter 1 μm, in which sulfate, nitrate, black and organic carbon are predominantly located; however the model underestimates coarse-mode number concentration and size, especially in the marine environment. This is more likely due to

  4. Atmospheric aerosols: Their Optical Properties and Effects (supplement)

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A digest of technical papers is presented. Topics include aerosol size distribution from spectral attenuation with scattering measurements; comparison of extinction and backscattering coefficients for measured and analytic stratospheric aerosol size distributions; using hybrid methods to solve problems in radiative transfer and in multiple scattering; blue moon phenomena; absorption refractive index of aerosols in the Denver pollution cloud; a two dimensional stratospheric model of the dispersion of aerosols from the Fuego volcanic eruption; the variation of the aerosol volume to light scattering coefficient; spectrophone in situ measurements of the absorption of visible light by aerosols; a reassessment of the Krakatoa volcanic turbidity, and multiple scattering in the sky radiance.

  5. Competing Atmospheric and Surface-Driven Impacts of Absorbing Aerosols on the East Asian Summer Monsoon

    NASA Astrophysics Data System (ADS)

    Persad, G.; Paynter, D.; Ming, Y.; Ramaswamy, V.

    2015-12-01

    Absorbing aerosols, by attenuating shortwave radiation within the atmosphere and reemitting it as longwave radiation, redistribute energy both vertically within the surface-atmosphere column and horizontally between polluted and unpolluted regions. East Asia has the largest concentrations of anthropogenic absorbing aerosols globally, and these, along with the region's scattering aerosols, have both reduced the amount of solar radiation reaching the Earth's surface regionally ("solar dimming") and increased shortwave absorption within the atmosphere, particularly during the peak months of the East Asian Summer Monsoon (EASM). We here analyze how atmospheric absorption and surface solar dimming compete in driving the response of EASM circulation to anthropogenic absorbing aerosols, which dominates, and why—issues of particular importance for predicting how the EASM will respond to projected changes in absorbing and scattering aerosol emissions in the future. We probe these questions in a state-of-the-art general circulation model (GCM) using a combination of realistic and idealized aerosol perturbations that allow us to analyze the relative influence of absorbing aerosols' atmospheric and surface-driven impacts on EASM circulation. In combination, our results make clear that, although absorption-driven dimming has a less detrimental effect on EASM circulation than purely scattering-driven dimming, aerosol absorption is still a net impairment to EASM strength when both its atmospheric and surface effects are considered. Because atmospheric heating is not efficiently conveyed to the surface, the surface dimming and associated cooling from even a pure absorber is sufficient to counteract its atmospheric heating, resulting in a net reduction in EASM strength. These findings elevate the current understanding of the impacts of aerosol absorption on the EASM, improving our ability to diagnose EASM responses to current and future regional changes in aerosol emissions.

  6. Infrared Aerosol Radiative Forcing at the Surface and the Top of the Atmosphere

    NASA Technical Reports Server (NTRS)

    Markowicz, Krzysztof M.; Flatau, Piotr J.; Vogelmann, Andrew M.; Quinn, Patricia K.; Welton, Ellsworth J.

    2003-01-01

    We study the clear-sky aerosol radiative forcing at infrared wavelengths using data from the Aerosol Characterization Experiment (ACE-Asia) cruise of the NOAA R/V Ronald H. Brown. Limited number of data points is analyzed mostly from ship and collocated satellite values. An optical model is derived from chemical measurements, lidar profiles, and visible extinction measurements which is used to and estimate the infrared aerosol optical thickness and the single scattering albedo. The IR model results are compared to detailed Fourier Transform Interferometer based infrared aerosol forcing estimates, pyrgeometer based infrared downward fluxes, and against the direct solar forcing observations. This combined approach attests for the self-consistency of the optical model and allows to derive quantities such as the infrared forcing at the top of the atmosphere or the infrared optical thickness. The mean infrared aerosol optical thickness at 10 microns is 0.08 and the single scattering albedo is 0.55. The modeled infrared aerosol forcing reaches 10 W/sq m during the cruise, which is a significant contribution to the total direct aerosol forcing. The surface infrared aerosol radiative forcing is between 10 to 25% of the shortwave aerosol forcing. The infrared aerosol forcing at the top of the atmosphere can go up to 19% of the solar aerosol forcing. We show good agreement between satellite (CERES instrument) retrievals and model results at the top of the atmosphere. Over the Sea of Japan, the average infrared radiative forcing is 4.6 W/sq m in the window region at the surface and it is 1.5 W/sq m at top of the atmosphere. The top of the atmosphere IR forcing efficiency is a strong function of aerosol temperature while the surface IR forcing efficiency varies between 37 and 55 W/sq m (per infrared optical depth unit). and changes between 10 to 18 W/sq m (per infrared optical depth unit).

  7. Formation of highly porous aerosol particles by atmospheric freeze-drying in ice clouds.

    PubMed

    Adler, Gabriela; Koop, Thomas; Haspel, Carynelisa; Taraniuk, Ilya; Moise, Tamar; Koren, Ilan; Heiblum, Reuven H; Rudich, Yinon

    2013-12-17

    The cycling of atmospheric aerosols through clouds can change their chemical and physical properties and thus modify how aerosols affect cloud microphysics and, subsequently, precipitation and climate. Current knowledge about aerosol processing by clouds is rather limited to chemical reactions within water droplets in warm low-altitude clouds. However, in cold high-altitude cirrus clouds and anvils of high convective clouds in the tropics and midlatitudes, humidified aerosols freeze to form ice, which upon exposure to subsaturation conditions with respect to ice can sublimate, leaving behind residual modified aerosols. This freeze-drying process can occur in various types of clouds. Here we simulate an atmospheric freeze-drying cycle of aerosols in laboratory experiments using proxies for atmospheric aerosols. We find that aerosols that contain organic material that undergo such a process can form highly porous aerosol particles with a larger diameter and a lower density than the initial homogeneous aerosol. We attribute this morphology change to phase separation upon freezing followed by a glass transition of the organic material that can preserve a porous structure after ice sublimation. A porous structure may explain the previously observed enhancement in ice nucleation efficiency of glassy organic particles. We find that highly porous aerosol particles scatter solar light less efficiently than nonporous aerosol particles. Using a combination of satellite and radiosonde data, we show that highly porous aerosol formation can readily occur in highly convective clouds, which are widespread in the tropics and midlatitudes. These observations may have implications for subsequent cloud formation cycles and aerosol albedo near cloud edges.

  8. Formation of highly porous aerosol particles by atmospheric freeze-drying in ice clouds

    PubMed Central

    Adler, Gabriela; Koop, Thomas; Haspel, Carynelisa; Taraniuk, Ilya; Moise, Tamar; Koren, Ilan; Heiblum, Reuven H.; Rudich, Yinon

    2013-01-01

    The cycling of atmospheric aerosols through clouds can change their chemical and physical properties and thus modify how aerosols affect cloud microphysics and, subsequently, precipitation and climate. Current knowledge about aerosol processing by clouds is rather limited to chemical reactions within water droplets in warm low-altitude clouds. However, in cold high-altitude cirrus clouds and anvils of high convective clouds in the tropics and midlatitudes, humidified aerosols freeze to form ice, which upon exposure to subsaturation conditions with respect to ice can sublimate, leaving behind residual modified aerosols. This freeze-drying process can occur in various types of clouds. Here we simulate an atmospheric freeze-drying cycle of aerosols in laboratory experiments using proxies for atmospheric aerosols. We find that aerosols that contain organic material that undergo such a process can form highly porous aerosol particles with a larger diameter and a lower density than the initial homogeneous aerosol. We attribute this morphology change to phase separation upon freezing followed by a glass transition of the organic material that can preserve a porous structure after ice sublimation. A porous structure may explain the previously observed enhancement in ice nucleation efficiency of glassy organic particles. We find that highly porous aerosol particles scatter solar light less efficiently than nonporous aerosol particles. Using a combination of satellite and radiosonde data, we show that highly porous aerosol formation can readily occur in highly convective clouds, which are widespread in the tropics and midlatitudes. These observations may have implications for subsequent cloud formation cycles and aerosol albedo near cloud edges. PMID:24297908

  9. Nonequilibrium Atmospheric Secondary Organic Aerosol Formation and Growth

    SciTech Connect

    Perraud, Veronique M.; Bruns, Emily A.; Ezell, Michael J.; Johnson, Stanley N.; Yu, Yong; Alexander, M. L.; Zelenyuk, Alla; Imre, D.; Chang, W. L.; Dabdub, Donald; Pankow, James F.; Finlayson-Pitts, Barbara J.

    2012-02-21

    Airborne particles play a critical role in air quality, human health effects, visibility and climate. Secondary organic aerosols (SOA) account for a significant portion of total airborne particles. They are formed in reactions of organic gases that produce low volatility and semi-volatile organic compounds (SVOCs). Current atmospheric models assume that SOA are liquids into which SVOCs undergo equilibrium partitioning and grow the particles. However a large discrepancy between model predictions and field measurements of SOA is commonly observed. We report here laboratory studies of the oxidation of a-pinene by ozone and nitrate radicals and show that particle composition is actually consistent with a kinetically determined growth mechanism, and not with equilibrium partitioning between the gas phase and liquid particles. If this is indeed a general phenomenon in air, the formulation of atmospheric SOA models will have to be revised to reflect this new paradigm. This will have significant impacts on quantifying the role of SOA in air quality, visibility, and climate.

  10. Metal and metalloid contaminants in atmospheric aerosols from mining operations

    NASA Astrophysics Data System (ADS)

    Csavina, Janae

    Mining operations, including crushing, grinding, smelting, refining, and tailings management, are a significant source of airborne metal and metalloid contaminants such as As, Pb, Cd and other potentially toxic elements. Dust particles emitted from mining operations can accumulate in surrounding soils, natural waters and vegetation at relatively high concentrations through wind and water transport. Human exposure to the dust can occur through inhalation and, especially in the case of children, incidental dust ingestion, particularly during the early years when children are likely to exhibit pica. Furthermore, smelting operations release metals and metalloids in the form of fumes and ultra-fine particulate matter, which disperses more readily than coarser soil dusts. Of specific concern, these fine particulates can be transported to the lungs, allowing contaminants to be transferred into the blood stream. The main aim of this research is to assess the role of atmospheric aerosol and dust in the transport of metal and metalloid contaminants from mining operations to assess the deleterious impacts of these emissions to ecology and human health. In a field campaign, ambient particulates from five mining sites and four reference sites were examined utilizing micro-orifice deposit impactors (MOUDI), total suspended particulate (TSP) collectors, a scanning mobility particle sizer (SMPS), and Dusttrak optical particle counters for an understanding of the fate and transport of atmospheric aerosols. One of the major findings from size-resolved chemical characterization at three mining sites showed that the majority of the contaminant concentrations were found in the fine size fraction (<1 micrometer). Further, metal and metalloids (e.g. As, Cd, and Pb) around smelting activities are significantly enriched in both the coarse and fine size fraction when compared to reference sites. Additionally, with dust events being a growing concern because of predicted climate change and

  11. Remote Sensing of Aerosol in the Terrestrial Atmosphere from Space: New Missions

    NASA Technical Reports Server (NTRS)

    Milinevsky, G.; Yatskiv, Ya.; Degtyaryov, O.; Syniavskyi, I.; Ivanov, Yu.; Bovchaliuk, A.; Mishchenko, M.; Danylevsky, V.; Sosonkin, M.; Bovchaliuk, V.

    2015-01-01

    The distribution and properties of atmospheric aerosols on a global scale are not well known in terms of determination of their effects on climate. This mostly is due to extreme variability of aerosol concentrations, properties, sources, and types. Aerosol climate impact is comparable to the effect of greenhouse gases, but its influence is more difficult to measure, especially with respect to aerosol microphysical properties and the evaluation of anthropogenic aerosol effect. There are many satellite missions studying aerosol distribution in the terrestrial atmosphere, such as MISR/Terra, OMI/Aura, AVHHR, MODIS/Terra and Aqua, CALIOP/CALIPSO. To improve the quality of data and climate models, and to reduce aerosol climate forcing uncertainties, several new missions are planned. The gap in orbital instruments for studying aerosol microphysics has arisen after the Glory mission failed during launch in 2011. In this review paper, we describe several planned aerosol space missions, including the Ukrainian project Aerosol-UA that obtains data using a multi-channel scanning polarimeter and wide-angle polarimetric camera. The project is designed for remote sensing of the aerosol microphysics and cloud properties on a global scale.

  12. Atmospheric aerosol characterization combining multi-wavelength Raman lidar and MAX-DOAS measurements in Gwanjgu

    NASA Astrophysics Data System (ADS)

    Chong, Jihyo; Shin, Dong Ho; Kim, Kwang Chul; Lee, Kwon-Ho; Shin, Sungkyun; Noh, Young M.; Müller, Detlef; Kim, Young J.

    2011-11-01

    Integrated approach has been adopted at the ADvanced Environmental Research Center (ADEMRC), Gwangju Institute of Science and Technology (GIST), Korea for effective monitoring of atmospheric aerosol. Various active and passive optical remote sensing techniques such as multi-wavelength (3β+2α+1δ) Raman LIDAR, sun-photometry, MAX-DOAS, and satellite retrieval have been utilized. This integrated monitoring system approach combined with in-situ surface measurement is to allow better characterization of physical and optical properties of atmospheric aerosol. Information on the vertical distribution and microphysical properties of atmospheric aerosol is important for understanding its transport characteristics as well as radiative effect. The GIST multi-wavelength (3β + 2α+1δ) Raman lidar system can measure vertical profiles of optical properties of atmospheric aerosols such as extinction coefficients at 355 and 532nm, particle backscatter coefficients at 355, 532 and 1064 nm, and depolarization ratio at 532nm. The incomplete overlap between the telescope field-of-view and beam divergence of the transmitting laser significantly affects lidar measurement, resulting in higher uncertainty near the surface where atmospheric aerosols of interest are concentrated. Differential Optical Absorption Spectroscopy (DOAS) technique is applied as a complementary tool for the detection of atmospheric aerosols near the surface. The passive Multi-Axis DOAS (MAX-DOAS) technique uses scattered sunlight as a light source from several viewing directions. Recently developed aerosol retrieval algorithm based on O4 slant column densities (SCDs) measured at UV and visible wavelengths has been utilized to derive aerosol information (e.g., aerosol optical depth (AOD) and aerosol extinction coefficients (AECs)) in the lower troposphere. The aerosol extinction coefficient at 356 nm was retrieved for the 0-1 and 1-2 km layers based on the MAX-DOAS measurements using the retrieval algorithm

  13. Vertical profiles of atmospheric fluorescent aerosols observed by a mutil-channel lidar spectrometer system

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Huang, J.; Zhou, T.; Sugimoto, N.; Bi, J.

    2015-12-01

    Zhongwei Huang1*, Jianping Huang1, Tian Zhou1, Nobuo Sugimoto2, Jianrong Bi1 and Jinsen Shi11Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou, China. 2Atmospheric Environment Division, National Institutes for Environmental Studies, Tsukuba, Japan Email: huangzhongwei@lzu.edu.cn Abstract Atmospheric aerosols have a significant impact on regional and globe climate. The challenge in quantifying aerosol direct radiative forcing and aerosol-cloud interactions arises from large spatial and temporal heterogeneity of aerosol concentrations, compositions, sizes, shape and optical properties (IPCC, 2007). Lidar offers some remarkable advantages for determining the vertical structure of atmospheric aerosols and their related optical properties. To investigate the characterization of atmospheric aerosols (especially bioaerosols) with high spatial and temporal resolution, we developed a Raman/fluorescence/polarization lidar system employed a multi-channel spectrometer, with capabilities of providing measurements of Raman scattering and laser-induced fluorescence excitation at 355 nm from atmospheric aerosols. Meanwhile, the lidar system operated polarization measurements both at 355nm and 532nm wavelengths, aiming to obtain more information of aerosols. It employs a high power pulsed laser and a received telescope with 350mm diameter. The receiver could simultaneously detect a wide fluorescent spectrum about 178 nm with spectral resolution 5.7 nm, mainly including an F/3.7 Crossed Czerny-Turner spectrograph, a grating (1200 gr/mm) and a PMT array with 32 photocathode elements. Vertical structure of fluorescent aerosols in the atmosphere was observed by the developed lidar system at four sites across northwest China, during 2014 spring field observation that conducted by Lanzhou University. It has been proved that the developed lidar could detect the fluorescent aerosols with high temporal and

  14. Measurements of Atmospheric Aerosol Vertical Distributions above Svalbard, Norway using Unmanned Aerial Systems (UAS)

    NASA Astrophysics Data System (ADS)

    Bates, T. S.; Johnson, J. E.; Stalin, S.; Telg, H.; Murphy, D. M.; Burkhart, J. F.; Quinn, P.; Storvold, R.

    2015-12-01

    Atmospheric aerosol vertical distributions were measured above Svalbard, Norway in April 2015 to investigate the processes controlling aerosol concentrations and radiative effects. The aerosol payload was flown in a NOAA/PMEL MANTA Unmanned Aerial System (UAS) on 9 flights totaling 19 flight hours. Measurements were made of particle number concentration and aerosol light absorption at three wavelengths, similar to those conducted in April 2011 (Bates et al., Atmos. Meas. Tech., 6, 2115-2120, 2013). A filter sample was collected on each flight for analyses of trace elements. Additional measurements in the aerosol payload in 2015 included aerosol size distributions obtained using a Printed Optical Particle Spectrometer (POPS) and aerosol optical depth obtained using a four wavelength miniature Scanning Aerosol Sun Photometer (miniSASP). The data show most of the column aerosol mass and resulting optical depth in the boundary layer but frequent aerosol layers aloft with high particle number concentration (2000 cm-3) and enhanced aerosol light absorption (1 Mm-1). Transport of these aerosol layers was assessed using FLEXPART particle dispersion models. The data contribute to an assessment of sources of BC to the Arctic and potential climate impacts.

  15. Atmospheric Teleconnection over Eurasia Induced by Aerosol Radiative Forcing During Boreal Spring

    NASA Technical Reports Server (NTRS)

    Kim, Maeng-Ki; Lau, K. M.; Chin, Mian; Kim, Kyu-Myong; Sud, Y. C.; Walker, Greg K.

    2005-01-01

    The direct effects of aerosols on global and regional climate during boreal spring are investigated based on simulations using the NASA Global Modeling and Assimilation Office (GMAO) finite-volume general circulation model (fvGCM) with Microphyics of clouds in Relaxed Arakawa Schubert Scheme (McRAS). The aerosol loading are prescribed from three-dimensional monthly distribution of tropospheric aerosols viz., sulfate, black carbon, organic carbon, soil dust, and sea salt from output of the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). The aerosol extinction coefficient, single scattering albedo, and asymmetric factor are computed as wavelength-dependent radiative forcing in the radiative transfer scheme of the fvGCM, and as a function of the aerosol loading and ambient relative humidity. We find that anomalous atmospheric heat sources induced by absorbing aerosols (dust and black carbon) excites a planetary scale teleconnection pattern in sea level pressure, temperature and geopotential height spanning North Africa through Eurasia to the North Pacific. Surface cooling due to direct effects of aerosols is found in the vicinity and downstream of the aerosol source regions, i.e., South Asia, East Asia, and northern and western Africa. Additionally, atmospheric heating is found in regions with large loading of dust (over Northern Africa, and Middle East), and black carbon (over South-East Asia). Paradoxically, the most pronounced feature in aerosol-induced surface temperature is an east-west dipole anomaly with strong cooling over the Caspian Sea, and warming over central and northeastern Asia, where aerosol concentration are low. Analyses of circulation anomalies show that the dipole anomaly is a part of an atmospheric teleconnection driven by atmospheric heating anomalies induced by absorbing aerosols in the source regions, but the influence was conveyed globally through barotropic energy dispersion and sustained by feedback processes

  16. Some results of an experimental study of the atmospheric aerosol in Tomsk: A combined approach

    SciTech Connect

    Zuev, V.V.

    1996-04-01

    As widely accepted, aerosols strongly contribute to the formation of the earth`s radiation balance through the absorption and scattering of solar radiation. In addition, aerosols, being active condensation nuclei, also have a role in the cloud formation process. In this paper, results are presented of aerosol studies undertaken at the field measurement sites of the Institute of Atmospheric Optics in Tomsk and the Tomsk region.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26694318

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

    PubMed

    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.

  19. How Well Will MODIS Measure Top of Atmosphere Aerosol Direct Radiative Forcing?

    NASA Technical Reports Server (NTRS)

    Remer, Lorraine A.; Kaufman, Yoram J.; Levin, Zev; Ghan, Stephen; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The new generation of satellite sensors such as the Moderate Resolution Imaging Spectroradiometer (MODIS) will be able to detect and characterize global aerosols with an unprecedented accuracy. The question remains whether this accuracy will be sufficient to narrow the uncertainties in our estimates of aerosol radiative forcing at the top of the atmosphere. Satellite remote sensing detects aerosol optical thickness with the least amount of relative error when aerosol loading is high. Satellites are less effective when aerosol loading is low. We use the monthly mean results of two global aerosol transport models to simulate the spatial distribution of smoke aerosol in the Southern Hemisphere during the tropical biomass burning season. This spatial distribution allows us to determine that 87-94% of the smoke aerosol forcing at the top of the atmosphere occurs in grid squares with sufficient signal to noise ratio to be detectable from space. The uncertainty of quantifying the smoke aerosol forcing in the Southern Hemisphere depends on the uncertainty introduced by errors in estimating the background aerosol, errors resulting from uncertainties in surface properties and errors resulting from uncertainties in assumptions of aerosol properties. These three errors combine to give overall uncertainties of 1.5 to 2.2 Wm-2 (21-56%) in determining the Southern Hemisphere smoke aerosol forcing at the top of the atmosphere. The range of values depend on which estimate of MODIS retrieval uncertainty is used, either the theoretical calculation (upper bound) or the empirical estimate (lower bound). Strategies that use the satellite data to derive flux directly or use the data in conjunction with ground-based remote sensing and aerosol transport models can reduce these uncertainties.

  20. Atmospheric Teleconnection over Eurasia Induced by Aerosol Radiative Forcing during Boreal Spring

    NASA Technical Reports Server (NTRS)

    Kim, Maeng-Ki; Lau, William K. M.; Chin, Mian; Kim, Kyu-Myong; Sud, Y. C.; Walker, Greg K.

    2006-01-01

    The direct effects of aerosols on global and regional climate during boreal spring are investigated based on numerical simulations with the NASA Global Modeling and Assimilation Office finite-volume general circulation model (fvGCM) with Microphyics of Clouds with the Relaxed Arakawa Schubert Scheme (McRAS), using aerosol forcing functions derived from the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). The authors find that anomalous atmospheric heat sources induced by absorbing aerosols (dust and black carbon) excite a planetary-scale teleconnection pattern in sea level pressure, temperature, and geopotential height spanning North Africa through Eurasia to the North Pacific. Surface cooling due to direct effects of aerosols is found in the vicinity and downstream of the aerosol source regions, that is, South Asia, East Asia, and northern and western Africa. Significant atmospheric heating is found in regions with large loading of dust (over northern Africa and the Middle East) and black carbon (over Southeast Asia). Paradoxically, the most pronounced feature in aerosol-induced surface temperature is an east west dipole anomaly with strong cooling over the Caspian Sea and warming over central and northeastern Asia, where aerosol concentrations are low. Analyses of circulation anomalies show that the dipole anomaly is a part of an atmospheric teleconnection pattern driven by atmospheric heating anomalies induced by absorbing aerosols in the source regions, but the influence was conveyed globally through barotropic energy dispersion and sustained by feedback processes associated with the regional circulations. The surface temperature signature associated with the aerosol-induced teleconnection bears striking resemblance to the spatial pattern of observed long-term trend in surface temperature over Eurasia. Additionally, the boreal spring wave train pattern is similar to that reported by Fukutomi et al. associated with the boreal summer

  1. Biogenic sulfur emissions and aerosols over the tropical South Atlantic: 3. Atmospheric dimethylsulfide, aerosols and cloud condensation nuclei

    NASA Astrophysics Data System (ADS)

    Andreae, Meinrat O.; Elbert, Wolfgang; de Mora, Stephen J.

    1995-06-01

    We measured dimethylsulfide in air (DMSa) and the number concentration, size distribution, and chemical composition of atmospheric aerosols, including the concentration of cloud condensation nuclei (CCN), during February-March 1991 over the tropical South Atlantic along 19°S (F/S Meteor, cruise 15/3). Aerosol number/size distributions were determined with a laser-optical particle counter, condensation nuclei (CN) concentrations with a TSI 3020, and cloud condensation nuclei (CCN) with a Hudson-type supersaturation chamber. Aerosol samples were collected on two-stage stacked filters and analyzed by ion chromatography for soluble ion concentrations. Black carbon in aerosols was measured by visible light absorption and used to identify and eliminate periods with anthropogenic pollution from the data set. Meteorological analysis shows that most of the air masses sampled had spent extended periods over remote marine areas in the tropical and subtropical region. DMSa was closely correlated with the sea-to- air DMS flux calculated from DMS concentrations in seawater and meteorological data. Sea salt made the largest contribution to aerosol mass and volume but provided only a small fraction of the aerosol number concentration. The submicron aerosol had a mean composition close to ammonium bisulfate, with the addition of some methanesulfonate. Aerosol (CN and CCN) number and non-sea-salt sulfate concentrations were significantly correlated with DMS concentration and flux. This suggests that DMS oxidation followed by aerosol nucleation and growth in the marine boundary layer is an important, if not dominating, source of CN and possibly CCN. The degree of correlation between DMS and particle concentrations in the marine boundary layer may be strongly influenced by the different time scales of the processes regulating these concentrations. Our results provide strong support for several aspects of the CLAW hypothesis, which proposes the existence of a feedback loop linking DMS

  2. Validation of The Standard Aerosol Models Used In The Atmospheric Correction Algorithms For Satellite Ocean Observation

    NASA Astrophysics Data System (ADS)

    Martiny, N.; Santer, R.

    Over ocean, the total radiance measured by the satellite sensors at the top of the atmo- sphere is mainly atmospheric. In order to access to the water leaving radiance, directly related to the concentration of the different components of the water, we need to cor- rect the satellite measurements from the important atmospheric contribution. In the atmosphere, the light emitted by the sun is scattered by the molecules, absorbed by the gases, and both scattered and absorbed in unknown proportions by the aerosols, particles confined in the first layer of the atmosphere due to their large size. The remote sensing of the aerosols represents then a complex step in the atmospheric correction scheme. Over ocean, the principle of the aerosol remote sensing lies on the assump- tion that the water is absorbent in the red and the near-infrared. The aerosol model is then deduced from these spectral bands and used to extrapolate the aerosol optical properties in the visible wavelengths. For ocean color sensors such as CZCS, OCTS, POLDER, SeaWiFS or MODIS, the atmospheric correction algorithms use standard aerosol models defined by Shettle &Fenn for their look-up-tables. Over coastal wa- ters, are these models still suitable? The goal of this work is to validate the standard aerosol models used in the atmospheric correction algorithms over coastal zones. For this work, we use ground-based in-situ measurements from the CIMEL sunphotome- ter instrument. Using the extinction measurements, we can deduce the aerosol spectral dependency which falls between the spectral dependency of two standard Shettle &Fenn aerosol models. After the interpolation of the aerosol model, we can use it to extrapolate in the visible the optical parameters needed for the atmospheric correction scheme: Latm, the atmospheric radiance and T, the atmospheric transmittance. The simulations are done using a radiative transfer code based on the successive order of scattering. Latm and T are then used for

  3. A new approach for the fractionation of water-soluble organic carbon in atmospheric aerosols and cloud drops

    NASA Astrophysics Data System (ADS)

    Andracchio, Antonella; Cavicchi, Catia; Tonelli, Domenica; Zappoli, Sergio

    A novel approach is described for the fractionation of water-soluble organic carbon (WSOC) in atmospheric aerosols and cloud drops. The method is based on the preliminary adsorption of the sample, acidified at pH 2, on a polymeric styrene-divinylbenzene resin (XAD-2) and subsequent elution with a series of solvents, which leads to the fractionation of the sample into three classes of compounds. The method was set up using synthetic mixtures of organic compounds and then applied to selected samples of atmospheric aerosols and cloud drops. All samples and collected fractions were analysed using size exclusion chromatography (SEC). This method proved particularly useful both in providing information on the organic content of the samples and for the characterisation of the macromolecular compounds (MMCs) in the samples. Synthetic samples were prepared using humic, fulvic and tannic acid to simulate naturally occurring MMCs. In the first fraction, eluted with HCl, only the most soluble organic compounds (oxalic acid, formic acid and acetic acid) were collected. In the second fraction, eluted with methanol, the major part of the organic material was collected together with the more hydrophilic constituents of the humic substances. In the third fraction, it was possible to separately recover the more hydrophobic component of the humic substances. A large number of atmospheric samples (fog, aerosol, cloud) were then analysed using SEC. Most of these samples evidenced a noteworthy chromatogram at 254 nm. Moreover, the chromatographic area evidenced a clear linear correlation with the total organic carbon (TOC) values. The fractionation method on XAD-2 was finally applied to selected atmospheric samples, yielding three classes of organic compounds. In each sample, a non-negligible amount of compounds with dimensional and chemical properties similar to humic substances were collected in the third fraction. The carbon content in this latter fraction was estimated both by TOC

  4. Atmospheric acidification of mineral aerosols: a source of bioavailable phosphorus for the oceans

    NASA Astrophysics Data System (ADS)

    Nenes, A.; Krom, M. D.; Mihalopoulos, N.; van Cappellen, P.; Shi, Z.; Bougiatioti, A.; Zarmpas, P.; Herut, B.

    2011-07-01

    Primary productivity of continental and marine ecosystems is often limited or co-limited by phosphorus. Deposition of atmospheric aerosols provides the major external source of phosphorus to marine surface waters. However, only a fraction of deposited aerosol phosphorus is water soluble and available for uptake by phytoplankton. We propose that atmospheric acidification of aerosols is a prime mechanism producing soluble phosphorus from soil-derived minerals. Acid mobilization is expected to be pronounced where polluted and dust-laden air masses mix. Our hypothesis is supported by the soluble compositions and reconstructed pH values for atmospheric particulate matter samples collected over a 5-yr period at Finokalia, Crete. In addition, at least tenfold increase in soluble phosphorus was observed when Saharan soil and dust were acidified in laboratory experiments which simulate atmospheric conditions. Aerosol acidification links bioavailable phosphorus supply to anthropogenic and natural acidic gas emissions, and may be a key regulator of ocean biogeochemistry.

  5. Atmospheric acidification of mineral aerosols: a source of bioavailable phosphorus for the oceans

    NASA Astrophysics Data System (ADS)

    Nenes, A.; Krom, M. D.; Mihalopoulos, N.; van Cappellen, P.; Shi, Z.; Bougiatioti, A.; Zarmpas, P.; Herut, B.

    2011-02-01

    Primary productivity of continental and marine ecosystems is often limited or co-limited by phosphorus. Deposition of atmospheric aerosols provides the major external source of phosphorus to surface waters. However, only a fraction of deposited aerosol phosphorus is water soluble and available for uptake by phytoplankton. We propose that atmospheric acidification of aerosols is a prime mechanism producing soluble phosphorus from soil-derived minerals. Acid mobilization is expected to be pronounced where polluted and dust-laden air masses mix. Our hypothesis is supported by the soluble compositions and reconstructed pH values for atmospheric particulate matter samples collected over a 5-year period at Finokalia, Crete. At least tenfold increase in soluble phosphorus is observed when Saharan soil and dust were acidified in laboratory experiments which simulate atmospheric conditions. Aerosol acidification links bioavailable phosphorus supply to anthropogenic and natural acidic gas emissions, and may be a key regulator of ocean biogeochemistry.

  6. A Computational Study of Acid Catalyzed Aerosol Reactions of Atmospherically Relevant Epoxides

    EPA Science Inventory

    Epoxides are important intermediates of atmospheric isoprene oxidation. Their subsequent reactions in the particle phase lead to the production of organic compounds detected in ambient aerosols. We apply density functional theory to determine the important kinetic factors that ...

  7. The spectroscopic search for the trace aerosols in the planetary atmospheres - the results of numerical simulations

    NASA Astrophysics Data System (ADS)

    Blecka, Maria I.

    2010-05-01

    The passive remote spectrometric methods are important in examinations the atmospheres of planets. The radiance spectra inform us about values of thermodynamical parameters and composition of the atmospheres and surfaces. The spectral technology can be useful in detection of the trace aerosols like biological substances (if present) in the environments of the planets. We discuss here some of the aspects related to the spectroscopic search for the aerosols and dust in planetary atmospheres. Possibility of detection and identifications of biological aerosols with a passive InfraRed spectrometer in an open-air environment is discussed. We present numerically simulated, based on radiative transfer theory, spectroscopic observations of the Earth atmosphere. Laboratory measurements of transmittance of various kinds of aerosols, pollens and bacterias were used in modeling.

  8. Aromatic organosulfates in atmospheric aerosols: synthesis, characterization, and abundance.

    PubMed

    Staudt, Sean; Kundu, Shuvashish; Lehmler, Hans-Joachim; He, Xianran; Cui, Tianqu; Lin, Ying-Hsuan; Kristensen, Kasper; Glasius, Marianne; Zhang, Xiaolu; Weber, Rodney J; Surratt, Jason D; Stone1, Elizabeth A

    2014-09-01

    Aromatic organosulfates are identified and quantified in fine particulate matter (PM2.5) from Lahore, Pakistan, Godavari, Nepal, and Pasadena, California. To support detection and quantification, authentic standards of phenyl sulfate, benzyl sulfate, 3-and 4-methylphenyl sulfate and 2-, 3-, and 4-methylbenzyl sulfate were synthesized. Authentic standards and aerosol samples were analyzed by ultra-performance liquid chromatography (UPLC) coupled to negative electrospray ionization (ESI) quadrupole time-of-flight (ToF) mass spectrometry. Benzyl sulfate was present in all three locations at concentrations ranging from 4 - 90 pg m(-3). Phenyl sulfate, methylphenyl sulfates and methylbenzyl sulfates were observed intermittently with abundances of 4 pg m(-3), 2-31 pg m(-3), 109 pg m(-3), respectively. Characteristic fragment ions of aromatic organosulfates include the sulfite radical ((•)SO3(-), m/z 80) and the sulfate radical ((•)SO4(-),m/z 96). Instrumental response factors of phenyl and benzyl sulfates varied by a factor of 4.3, indicating that structurally-similar organosulfates may have significantly different instrumental responses and highlighting the need to develop authentic standards for absolute quantitation organosulfates. In an effort to better understand the sources of aromatic organosulfates to the atmosphere, chamber experiments with the precursor toluene were conducted under conditions that form biogenic organosulfates. Aromatic organosulfates were not detected in the chamber samples, suggesting that they form through different pathways, have different precursors (e.g. naphthalene or methylnaphthalene), or are emitted from primary sources.

  9. Aromatic organosulfates in atmospheric aerosols: Synthesis, characterization, and abundance

    NASA Astrophysics Data System (ADS)

    Staudt, Sean; Kundu, Shuvashish; Lehmler, Hans-Joachim; He, Xianran; Cui, Tianqu; Lin, Ying-Hsuan; Kristensen, Kasper; Glasius, Marianne; Zhang, Xiaolu; Weber, Rodney J.; Surratt, Jason D.; Stone, Elizabeth A.

    2014-09-01

    Aromatic organosulfates are identified and quantified in fine particulate matter (PM2.5) from Lahore, Pakistan, Godavari, Nepal, and Pasadena, California. To support detection and quantification, authentic standards of phenyl sulfate, benzyl sulfate, 3- and 4-methylphenyl sulfate and 2-, 3-, and 4-methylbenzyl sulfate were synthesized. Authentic standards and aerosol samples were analyzed by ultra-performance liquid chromatography (UPLC) coupled to negative electrospray ionization (ESI) quadrupole time-of-flight (ToF) mass spectrometry. Benzyl sulfate was present in all three locations at concentrations ranging from 4 to 90 pg m-3. Phenyl sulfate, methylphenyl sulfates and methylbenzyl sulfates were observed intermittently with abundances of 4 pg m-3, 2-31 pg m-3, 109 pg m-3, respectively. Characteristic fragment ions of aromatic organosulfates include the sulfite radical (rad SO3-, m/z 80) and the sulfate radical (rad SO4-, m/z 96). Instrumental response factors of phenyl and benzyl sulfates varied by a factor of 4.3, indicating that structurally-similar organosulfates have significantly different instrumental responses and highlighting the need to develop authentic standards for absolute quantitation organosulfates. In an effort to better understand the sources of aromatic organosulfates to the atmosphere, chamber experiments with the precursor toluene were conducted under conditions that form biogenic organosulfates. Aromatic organosulfates were not detected in the chamber samples, suggesting that they form through different pathways, have different precursors (e.g. naphthalene or methylnaphthalene), or are emitted from primary sources.

  10. Constraining the atmospheric composition of the day-night terminators of HD 189733b: Atmospheric retrieval with aerosols

    SciTech Connect

    Lee, Jae-Min; Irwin, Patrick G. J.; Fletcher, Leigh N.; Barstow, Joanna K.; Heng, Kevin

    2014-07-01

    A number of observations have shown that Rayleigh scattering by aerosols dominates the transmission spectrum of HD 189733b at wavelengths shortward of 1 μm. In this study, we retrieve a range of aerosol distributions consistent with transmission spectroscopy between 0.3-24 μm that were recently re-analyzed by Pont et al. To constrain the particle size and the optical depth of the aerosol layer, we investigate the degeneracies between aerosol composition, temperature, planetary radius, and molecular abundances that prevent unique solutions for transit spectroscopy. Assuming that the aerosol is composed of MgSiO{sub 3}, we suggest that a vertically uniform aerosol layer over all pressures with a monodisperse particle size smaller than about 0.1 μm and an optical depth in the range 0.002-0.02 at 1 μm provides statistically meaningful solutions for the day/night terminator regions of HD 189733b. Generally, we find that a uniform aerosol layer provide adequate fits to the data if the optical depth is less than 0.1 and the particle size is smaller than 0.1 μm, irrespective of the atmospheric temperature, planetary radius, aerosol composition, and gaseous molecules. Strong constraints on the aerosol properties are provided by spectra at wavelengths shortward of 1 μm as well as longward of 8 μm, if the aerosol material has absorption features in this region. We show that these are the optimal wavelengths for quantifying the effects of aerosols, which may guide the design of future space observations. The present investigation indicates that the current data offer sufficient information to constrain some of the aerosol properties of HD189733b, but the chemistry in the terminator regions remains uncertain.

  11. Spatio-temporal variability of aerosols in the tropics relationship with atmospheric and oceanic environments

    NASA Astrophysics Data System (ADS)

    Zuluaga-Arias, Manuel D.

    2011-12-01

    Earth's radiation budget is directly influenced by aerosols through the absorption of solar radiation and subsequent heating of the atmosphere. Aerosols modulate the hydrological cycle indirectly by modifying cloud properties, precipitation and ocean heat storage. In addition, polluting aerosols impose health risks in local, regional and global scales. In spite of recent advances in the study of aerosols variability, uncertainty in their spatio-temporal distributions still presents a challenge in the understanding of climate variability. For example, aerosol loading varies not only from year to year but also on higher frequency intraseasonal time scales producing strong variability on local and regional scales. An assessment of the impact of aerosol variability requires long period measurements of aerosols at both regional and global scales. The present dissertation compiles a large database of remotely sensed aerosol loading in order to analyze its spatio-temporal variability, and how this load interacts with different variables that characterize the dynamic and thermodynamic states of the environment. Aerosol Index (AI) and Aerosol Optical Depth (AOD) were used as measures of the atmospheric aerosol load. In addition, atmospheric and oceanic satellite observations, and reanalysis datasets is used in the analysis to investigate aerosol-environment interactions. A diagnostic study is conducted to produce global and regional aerosol satellite climatologies, and to analyze and compare the validity of aerosol retrievals. We find similarities and differences between the aerosol distributions over various regions of the globe when comparing the different satellite retrievals. A nonparametric approach is also used to examine the spatial distribution of the recent trends in aerosol concentration. A significant positive trend was found over the Middle East, Arabian Sea and South Asian regions strongly influenced by increases in dust events. Spectral and composite analyses

  12. Evolution of Titan's atmospheric aerosol under high-altitude ultraviolet irradiation

    NASA Astrophysics Data System (ADS)

    Tigrine, S.; Carrasco, N.; Mahjoub, A.; Fleury, B.; Cernogora, G.; Nahon, L.; Pernot, P.; Gudipati, M.

    2015-10-01

    The Cassini-Huygens space mission revealed that the chemistry initiating Titan's aerosols formation starts in the upper layers of the atmosphere (~1000 km). The grains then sediment until deposition at the surface. Despite all the data collected, the photochemical evolution of the aerosols between 1000 and 600 km is still unknown, especially regarding their optical properties. The aim of this work is to investigate the photochemical aging processes of those aerosols and how they interact with the VUV solar radiations. We put our results in perspective with the Cassini data for different atmospheric altitudes.

  13. Influence of Surface Seawater and Atmospheric Conditions on the Ccn Activity of Ocean-Derived Aerosol

    NASA Astrophysics Data System (ADS)

    Quinn, P.; Bates, T. S.; Russell, L. M.; Frossard, A. A.; Keene, W. C.; Kieber, D. J.; Hakala, J. P.

    2012-12-01

    Ocean-derived aerosols are produced from direct injection into the atmosphere (primary production) and gas-to-particle conversion in the atmosphere (secondary production). These different production mechanisms result in a broad range of particle sizes that has implications for the impact of ocean-derived aerosol on climate. The chemical composition of ocean-derived aerosols is a result of a complex mixture of inorganic sea salt and organic matter including polysaccharides, proteins, amino acids, microorganisms and their fragments, and secondary oxidation products. Both production mechanisms and biological processes in the surface ocean impact the ability of ocean-derived aerosol to act as cloud condensation nuclei (CCN). In addition, CCN activity can be impacted by atmospheric processing that modifies particle size and composition after the aerosol is emitted from the ocean. To understand relationships between production mechanism, surface ocean biology, and atmospheric processing, measurements were made of surface ocean chlorophyll and dissolved organic matter; nascent sea spray aerosol freshly emitted from the ocean surface; and ambient marine aerosol. These measurements were made along the coast of California and in the North Atlantic between the northeast US and Bermuda. These regions include both eutrophic and oligotraphic waters and, thus, provide for observations over a wide range of ocean conditions.

  14. Effect of relative humidity on mixed aerosols in atmosphere.

    PubMed

    Lee, W M; Huang, W M; Chen, Y Y

    2001-01-01

    In this study, the effects of relative humidity on the deliquescent point and size of internally mixed aerosols diameter, NH4NO3 and (NH4)2SO4 were investigated using a Tandem Differential Mobility Analyzer (TDMA) with a relative humidity conditioner. The growth of mixed aerosols appears to have two deliquescent steps. The first one was at about 61.2-61.3%, but the second one was at around 77-78%. At the first deliquescence point, growth ratio at phase change was 7.5%, which agrees with the growth ratio of ammonium nitrate aerosol. Growth ratio of phase change at the second deliquescence point was about 20%, lower than the growth ratio of ammonium sulfate aerosol. In the relative humidity range of 80-85%, the growth ratio of the mixed aerosols reached 60%. In other words, it appears that growth ratio increases with the size of aerosol. Furthermore, a theoretical growth model of mixed aerosols was developed and applied to estimate the amount of composition of the mixed aerosols dissolved at each deliquescence point. The results also show that some of ammonium sulfate already dissolved at the first deliquescence point according to the theoretical growth model.

  15. Effects of Aerosol on Atmospheric Dynamics and Hydrologic Processes During Boreal Spring and Summer

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Kim, M. K.; Kim, K. M.; Chin, Mian

    2005-01-01

    Global and regional climate impacts of present-day aerosol loading during boreal spring are investigated using the NASA finite volume General Circulation Model (fvGCM). Three-dimensional distributions of loadings of five species of tropospheric aerosols, i.e., sulfate, black carbon, organic carbon, soil dust, and sea salt are prescribed from outputs of the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). The aerosol loadings are used to calculate the extinction coefficient, single scattering albedo, and asymmetric factor at eleven spectral wavelengths in the radiative transfer code. We find that aerosol-radiative forcing during boreal spring excites a wavetrain-like pattern in tropospheric temperature and geopotential height that emanates from Northern Africa, through Eurasia, to northeastern Pacific. Associated with the teleconnection is strong surface cooling over regions with large aerosol loading, i.e., China, India, and Africa. Low-to-mid tropospheric heating due to shortwave absorption is found in regions with large loading of dust (Northern Africa, and central East Asia), and black carbon (South and East Asia). In addition pronounced surface cooling is found over the Caspian Sea and warming over Eurasian and northeastern Asia, where aerosol loadings are relatively low. These warming and cooling are components of teleconnection pattern produced primarily by atmospheric heating from absorbing aerosols, i.e., dust from North Africa and black carbon from South and East Asia. Effects of aerosols on atmospheric hydrologic cycle in the Asian monsoon region are also investigated. Results show that absorbing aerosols, i.e., black carbon and dust, induce large-scale upper-level heating anomaly over the Tibetan Plateau in April and May, ushering in an early onset of the Indian summer monsoon. Absorbing aerosols also enhance lower-level heating and anomalous ascent over northern India, intensifying the Indian monsoon. Overall, the aerosol

  16. Effects of Aerosol on Atmospheric Dynamics and Hydrologic Processes during Boreal Spring and Summer

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Kim, M. K.; Chin, Mian; Kim, K. M.

    2005-01-01

    Global and regional climate impacts of present-day aerosol loading during boreal spring are investigated using the NASA finite volume General Circulation Model (fvGCM). Three-dimensional distributions of loadings of five species of tropospheric aerosols, i.e., sulfate, black carbon, organic carbon, soil dust, and sea salt are prescribed from outputs of the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). The aerosol loadings are used to calculate the extinction coefficient, single scattering albedo, and asymmetric factor at eleven spectral wavelengths in the radiative transfer code. We find that aerosol-radiative forcing during boreal spring excites a wavetrain-like pattern in tropospheric temperature and geopotential height that emanates from Northern Africa, through Eurasia, to northeastern Pacific. Associated with the teleconnection is strong surface cooling over regions with large aerosol loading, i.e., China, India, and Africa. Low-to-mid tropospheric heating due to shortwave absorption is found in regions with large loading of dust (Northern Africa, and central East Asia), and black carbon (South and East Asia). In addition pronounced surface cooling is found over the Caspian Sea and warming over Eurasian and northeastern Asia, where aerosol loadings are relatively low. These warming and cooling are components of teleconnection pattern produced primarily by atmospheric heating from absorbing aerosols, i.e., dust from North Africa and.black carbon from South and East Asia. Effects of aerosols on atmospheric hydrologic cycle in the Asian monsoon region are also investigated. Results show that absorbing aerosols, i.e., black carbon and dust, induce large-scale upper-level heating anomaly over the Tibetan Plateau in April and May, ushering in an early onset of the Indian summer monsoon. Absorbing aerosols also enhance lower-level heating and anomalous ascent over northern India, intensifying the Indian monsoon. Overall, the aerosol

  17. The Effect of Aerosol Formation on Stable Isotopes Ratio in Titan's Atmosphere

    NASA Astrophysics Data System (ADS)

    Gautier, Thomas; Trainer, Melissa G.; Sebree, Joshua; Wold, Allison; Stern, Jennifer

    2016-10-01

    The formation of large amounts of aerosol in Titan atmosphere induces a significant sink for carbon and nitrogen in the atmosphere. Due to the high complexity of the chemistry leading to aerosol formation, there may be isotopic fractionation along the formation pathways of the aerosol. So far several stable isotopes have been measured in Titan atmosphere including the 13C/12C, 15N/14N and D/H ratios for different gaseous species. However, the fractionation effect of the aerosol formation and its impact on atmospheric stable isotope ratios has yet to be fully understood. Two experimental studies were recently published on the stable carbon [1] and nitrogen [1,2] isotope fractionation during aerosol formation in N2-CH4 reactant mixture. To better constrain the fractionation effect of aerosol formation on the Titan atmosphere we have measured the isotopic fractionation induced in laboratory aerosol analogues produced exploring the space of parameters that are expected to have an effect on fractionation processes. Parameters studied include pressure and temperature of aerosol formation and the reactant gas phase composition, including the standard "Titan" mixture of CH4/N2 as well as other trace species such as benzene (C6H6).[1] Sebree, J.A., Stern, J.C., Mandt, K.E., Domagal-Goldman, S.D., and Trainer, M.G.: C and N Fractionation of CH /N Mixtures during Photochemical Aerosol Formation: Relevance to Titan, (2016) Icarus 270:421-428[2] Kuga, M., Carrasco, N., Marty, B., Marrochi, Y., Bernard, S., Rigaudier, T., Fleury, B., Tissandier, L.: Nitrogen isotopic fractionation during abiotic synthesis of organic solid particles, (2014) EPSL 393:2-13

  18. Research highlights: laboratory studies of the formation and transformation of atmospheric organic aerosols.

    PubMed

    Borduas, Nadine; Lin, Vivian S

    2016-04-01

    Atmospheric particles are emitted from a variety of anthropogenic and natural precursors and have direct impacts on climate, by scattering solar irradiation and nucleating clouds, and on health, by causing oxidative stress in the lungs when inhaled. They may also form from gaseous precursors, creating complex mixtures of organic and inorganic material. The chemical composition and the physical properties of aerosols will evolve during their one-week lifetime which will consequently change their impact on climate and health. The heterogeneity of aerosols is difficult to model and thus atmospheric aerosol research strives to characterize the mechanisms involved in nucleating and transforming particles in the atmosphere. Recent advances in four laboratory studies of aerosol formation and aging are highlighted here.

  19. Scanning Transmission X-ray Microscopy: Applications in Atmospheric Aerosol Research

    SciTech Connect

    Moffet, Ryan C.; Tivanski, Alexei V.; Gilles, Mary K.

    2011-01-20

    Scanning transmission x-ray microscopy (STXM) combines x-ray microscopy and near edge x-ray absorption fine structure spectroscopy (NEXAFS). This combination provides spatially resolved bonding and oxidation state information. While there are reviews relevant to STXM/NEXAFS applications in other environmental fields (and magnetic materials) this chapter focuses on atmospheric aerosols. It provides an introduction to this technique in a manner approachable to non-experts. It begins with relevant background information on synchrotron radiation sources and a description of NEXAFS spectroscopy. The bulk of the chapter provides a survey of STXM/NEXAFS aerosol studies and is organized according to the type of aerosol investigated. The purpose is to illustrate the current range and recent growth of scientific investigations employing STXM-NEXAFS to probe atmospheric aerosol morphology, surface coatings, mixing states, and atmospheric processing.

  20. Atmospheric aerosol optical parameters, deep convective clouds and hail occurence - a correlation study

    NASA Astrophysics Data System (ADS)

    Talianu, Camelia; Andrei, Simona; Toanca, Florica; Stefan, Sabina

    2016-04-01

    Among the severe weather phenomena, whose frequency has increased during the past two decades, hail represents a major threat not only for agriculture but also for other economical fields. Generally, hail are produced in deep convective clouds, developed in an unstable environment. Recent studies have emphasized that besides the state of the atmosphere, the atmospheric composition is also very important. The presence of fine aerosols in atmosphere could have a high impact on nucleation processes, initiating the occurrence of cloud droplets, ice crystals and possibly the occurrence of graupel and/or hail. The presence of aerosols in the atmosphere, correlated with specific atmospheric conditions, could be predictors of the occurrence of hail events. The atmospheric investigation using multiwavelength Lidar systems can offer relevant information regarding the presence of aerosols, identified using their optical properties, and can distinguish between spherical and non-spherical shape, and liquid and solid phase of these aerosols. The aim of this study is to analyse the correlations between the presence and the properties of aerosols in atmosphere, and the production of hail events in a convective environment, using extensive and intensive optical parameters computed from lidar and ceilometer aerosols measurements. From these correlations, we try to evaluate if these aerosols can be taken into consideration as predictors for hail formation. The study has been carried out in Magurele - Romania (44.35N, 26.03E, 93m ASL) using two collocated remote sensing systems: a Raman Lidar (RALI) placed at the Romanian Atmospheric 3D Observatory and a ceilometer CL31 placed at the nearby Faculty of Physics, University of Bucharest. To evaluate the atmospheric conditions, radio sounding and satellite images were used. The period analysed was May 1st - July 15th, 2015, as the May - July period is climatologically favorable for deep convection events. Two hail events have been

  1. Atmospheric Black Carbon: Chemical Bonding and Structural Information of Individual Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Gilles, M. K.; Tivanski, A. V.; Hopkins, R. J.; Marten, B. D.

    2006-12-01

    The formation of aerosols from both natural and anthropogenic sources affects the Earth's temperature and climate by altering the radiative properties of the atmosphere. Aerosols containing black carbon (BC) that are released into the atmosphere from the burning of biomass, natural fires and the combustion of coals, diesel and jet fuels, contribute a large positive component to this radiative forcing, thus causing a heating of the atmosphere. A distinct type of biomass burn aerosol referred to as "tar balls" has recently been reported in the literature and is characterized by a spherical morphology, high carbon content and ability to efficiently scatter and absorb light. At present, very little is known about the exact nature and variation of the range of BC aerosols in the atmosphere with regards to optical, chemical and physical properties. Additionally, the similarity of these aerosols to surrogates used in the laboratory as atmospheric mimics remains unclear. The local chemical bonding, structural ordering and carbon-to-oxygen ratios of a plethora of black carbon standard reference materials (BC SRMs), high molecular mass humic-like substances (HULIS) and atmospheric aerosols from a variety of sources are examined using scanning transmission X-ray microscopy (STXM) coupled with near edge X-ray absorption fine structure (NEXAFS) spectroscopy. STXM/NEXAFS enables single aerosol particles of diameter upwards of 100 nm to be studied, which allows the diversity of atmospheric aerosol collected during a variety of field missions to be assessed. We apply a semi-quantitative peak fitting method to the recorded NEXAFS spectral fingerprints allowing comparison of BC SRMs and HULIS to BC aerosol originating from anthropogenic combustion and biomass burning events. This method allows us to distinguish between anthropogenic combustion and biomass burn aerosol using both chemical bonding and structural ordering information. The STXM/NEXAFS technique has also been utilized to

  2. Atmospheric stability effects on potential radiological releases at a nuclear research facility in Romania: Characterising the atmospheric mixing state.

    PubMed

    Chambers, Scott D; Galeriu, Dan; Williams, Alastair G; Melintescu, Anca; Griffiths, Alan D; Crawford, Jagoda; Dyer, Leisa; Duma, Marin; Zorila, Bogdan

    2016-04-01

    A radon-based nocturnal stability classification scheme is developed for a flat inland site near Bucharest, Romania, characterised by significant local surface roughness heterogeneity, and compared with traditional meteorologically-based techniques. Eight months of hourly meteorological and atmospheric radon observations from a 60 m tower at the IFIN-HH nuclear research facility are analysed. Heterogeneous surface roughness conditions in the 1 km radius exclusion zone around the site hinder accurate characterisation of nocturnal atmospheric mixing conditions using conventional meteorological techniques, so a radon-based scheme is trialled. When the nocturnal boundary layer is very stable, the Pasquill-Gifford "radiation" scheme overestimates the atmosphere's capacity to dilute pollutants with near-surface sources (such as tritiated water vapour) by 20% compared to the radon-based scheme. Under these conditions, near-surface wind speeds drop well below 1 m s(-1) and nocturnal mixing depths vary from ∼ 25 m to less than 10 m above ground level (a.g.l.). Combining nocturnal radon with daytime ceilometer data, we were able to reconstruct the full diurnal cycle of mixing depths. Average daytime mixing depths at this flat inland site range from 1200 to 1800 m a.g.l. in summer, and 500-900 m a.g.l. in winter. Using tower observations to constrain the nocturnal radon-derived effective mixing depth, we were able to estimate the seasonal range in the Bucharest regional radon flux as: 12 mBq m(-2) s(-1) in winter to 14 mBq m(-2) s(-1) in summer.

  3. Aliphatic and polycyclic aromatic hydrocarbons characterisation of Coimbra and Oporto PM2.5 urban aerosol

    NASA Astrophysics Data System (ADS)

    Rocha, A. C.; Mirante, F.; Gonçalves, C.; Nunes, T.; Alves, C.; Evtyugina, M.; Kowacz, M.; Pio, C.; Rocha, C.; Vasconcelos, T.

    2009-04-01

    The concentration of organic pollutants in urban areas is mostly due to incomplete combustion from vehicles, industries and domestic heating. Some of these compounds, principally the aliphatic (ALIPH) and polycyclic aromatic hydrocarbons (PAHs) promote harmful effects in human health. The determination of the ALIPH and PAHs concentration levels and their possible emission sources are useful for air quality management and source apportionment studies. In order to estimate and compare the ambient concentrations and establish the main sources of these compounds, the fine fraction of the atmospheric particulate matter (PM2.5) was collected simultaneously in Oporto and Coimbra during summer and winter seasons using a high volume sampler. The organic compounds were extracted from the particulate matter, under reflux with dichloromethane and the total organic extract (TOE) was fractionated by flash chromatography using five different eluents with increasing polarity. The hydrocarbon fractions were analysed by gas chromatography/mass spectrometry (GC/MS). Here we present and discuss the qualitative and quantitative composition of the aliphatic and aromatic fractions present in PM2.5 samples from both cities. The homologous series of C14 to C34 n-alkanes, isoprenoid hydrocarbons (pristane and phytane), PAHs and some petroleum markers have been identified and quantified. With the purpose of identifying the possible sources, various molecular diagnostic ratios were calculated. The global carbon preference index (CPI) closer to the unity, the large concentration of the unresolved complex mixture (UCM) and the presence of PAHs indicate that motor vehicle exhaust was the main emission source of the aliphatic and polycyclic aromatic fractions of Oporto and Coimbra aerosol, especially in the first city. Also, the remarkable presence of petroleum biomarkers such, as hopanes, confirms the previous results. Concentration ratios between PAHs were calculated and used to assign emission

  4. Unraveling the Complexity of Atmospheric Aerosol: Insights from Ultrahigh Resolution Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Mazzoleni, Lynn R.; Zhao, Yunzhu; Samburova, Vera; Gannet Hallar, A.; Lowenthal, Douglas

    2016-04-01

    Atmospheric aerosol organic matter (AOM) is a complex mixture of thousands of organic compounds, which may have significant influence on the climate-relevant properties of atmospheric aerosols. An improved understanding of the molecular composition of AOM is needed to evaluate the effect of aerosol composition upon aerosol physical properties. Products of gas, aqueous and particle phase reactions contribute to the aerosol organic mass. Thus, ambient aerosols carry a complex array of AOM components with variable chemical signatures depending upon its origin and aerosol life-cycle processes. In this work, ultrahigh-resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize ambient aerosol AOM collected at the Storm Peak Laboratory (3210 m a.s.l.) near Steamboat Springs, CO. Thousands of molecular formulas were assigned in the mass range of m/z 100-800 after negative-ion electrospray ionization. Using multivariate statistical analysis, correlations between the site meteorological conditions and specific molecular compositions were identified. For example, days with strong UV radiation and high temperature were found to contain large numbers of biogenic SOA molecular formulas. Similarly, days with high relative humidity and high sulfate concentrations were found to contain many sulfur-containing compounds, suggesting their aqueous phase formation.

  5. Ocean-atmosphere-wave characterisation of a wind jet (Ebro shelf, NW Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Grifoll, Manel; Navarro, Jorge; Pallares, Elena; Ràfols, Laura; Espino, Manuel; Palomares, Ana

    2016-06-01

    In this contribution the wind jet dynamics in the northern margin of the Ebro River shelf (NW Mediterranean Sea) are investigated using coupled numerical models. The study area is characterised by persistent and energetic offshore winds during autumn and winter. During these seasons, a seaward wind jet usually develops in a ˜ 50 km wide band offshore. The COAWST (Coupled Ocean-Atmosphere-Wave-Sediment Transport) modelling system was implemented in the region with a set of downscaling meshes to obtain high-resolution meteo-oceanographic outputs. Wind, waves and water currents were compared with in situ observations and remote-sensing-derived products with an acceptable level of agreement. Focused on an intense offshore wind event, the modelled wind jet appears in a limited area offshore with strong spatial variability. The wave pattern during the wind jet is characterised by the development of bimodal directional spectra, and the ocean circulation tends to present well-defined two-layer flow in the shallower region (i.e. inner shelf). The outer shelf tends to be dominated by mesoscale dynamics such as the slope current. Due to the limited fetch length, ocean surface roughness considering sea state (wave-atmosphere coupling) modifies to a small extent the wind and significant wave height under severe cross-shelf wind events. However, the coupling effect in the wind resource assessment may be relevant due to the cubic relation between the wind intensity and power.

  6. Sensitivity of the atmospheric temperature profile to the aerosol absorption in the presence of dust

    NASA Astrophysics Data System (ADS)

    Gómez-Amo, J. L.; di Sarra, A.; Meloni, D.

    2014-12-01

    Radiative transfer simulations in the shortwave (SW) and longwave (LW) spectral regions have been carried out to investigate the time evolution of the atmospheric heating/cooling rates and their influence on the temperature profiles under different vertical distributions of the aerosol absorption. The case study is based on measurements made at Rome, Italy, on 20 June 2007, when a dust layer was present above the urban boundary layer (BL) and the column aerosol optical depth at 550 nm was about 0.37. Column-integrated aerosol optical depth and single scattering albedo, as well as vertical profiles of aerosol extinction and meteorological variables have been derived from observations and used in the simulations. Different profiles of the aerosol absorption are considered by varying the absorption of the BL aerosols and of the desert dust, without changing the overall columnar properties. Three scenarios have been considered, with absorbing (ABL) or scattering (SBL) particles in the BL, and with a vertically homogeneous case (HL), which is taken as the reference. Calculations show that, for the selected case, about 25% of the SW heating is offset by the LW cooling within the dust layer. Different longwave/all-wave contributions are observed in the BL, depending on the BL aerosol absorption. Changes of atmospheric temperature induced by aerosol-radiation interactions only, have been investigated, while interactions with the surface through changes of the latent and sensible heat flux have been neglected. The evolution of temperature is similar for the three scenarios within the dust layer, with a daytime increase and a smaller nighttime decrease. After 24 h, the increase of the atmospheric temperature due to the aerosol radiative processes is about 1 K. In the BL, the increase of temperature is strongly dependent on the aerosol absorption capability. The oscillatory behaviour of the temperature with time in the dust layer, and the different evolution in the BL are

  7. Characterisation of Fluorescent Biological Aerosol Particles during South-West Monsoon from a High Altitude Site in South India

    NASA Astrophysics Data System (ADS)

    Valsan, A. E.; R, R.; V, B. C.; Huffman, J. A.; Poeschl, U.; Gunthe, S. S.

    2015-12-01

    Biological aerosols (Bioaerosols) constitute a wide range of dead and alive biological materials that are suspended in the atmosphere. Though ubiquitous in earth's atmosphere, bioaerosols are poorly characterized in terms of their atmospheric abundance, sources and physical properties. Here we discuss the number concentration and size distribution of coarse mode (>1µm) biological aerosols measured at a relatively clean high altitude continental site, Munnar (10.09 N, 77.06 E; 1605 m asl) located in the Western Ghats mountain ranges of Southern Tropical India. The fluorescent biological aerosol particles (FBAP) were continuously measured using Ultra Violet Aerodynamic Particle Sizer (UVAPS) from 01 June to 21 August 2014 (South-West Monsoon Period) which showed some interesting patterns. The mean number and mass concentration of coarse FBAP during the campaign was observed to be 1.7 x 10-2cm-3 and 0.24µg m-3 respectively, which corresponds to 2% and 9% of coarse total aerosol particles (TAP) number and mass concentration. FBAP concentration decreased significantly during periods of heavy and continuous rain with constant South-West winds. This may be due to the clean marine influx coming from the ocean and continuous washout. The Relative Humidity (RH) and temperature remained consistent during this period without any strong diurnal pattern. When the wind fluctuated in North-West directions, the FBAP concentration increased to even an order of magnitude higher than the periods of South-West winds which can be attributed to the transported bioaerosols from the nearby vegetated area. In spite of variability in the number concentrations, the size distribution of FBAP exhibited a prominent peak at ~3 μm throughout the campaign, which should be fungal spores. They also exhibited a strong diurnal pattern with high concentrations occuring during the night time which peaks in the early morning hours.Biological aerosols (Bioaerosols) constitute a wide range of dead and

  8. The impact of atmospheric aerosols on trace metal chemistry in open ocean surface seawater, 1. Aluminum

    NASA Astrophysics Data System (ADS)

    Maring, H. B.; Duce, R. A.

    1987-08-01

    Significant quantities of aerosol aluminum are transported from continental regions through the atmosphere to the oceans. Enrichments in the concentration of dissolved aluminum in open ocean surface seawater suggest that dissolution of aerosol aluminum is an important source of dissolved aluminum to these waters. Atmospheric aerosols collected at Enewetak Atoll were exposed to seawater and artificial rain water to determine directly the importance of atmospheric deposition as a source of marine dissolved aluminum. The results of these experiments indicate that ˜ 8-10% of the aluminum in atmospheric aerosols of crustal origin over the North Pacific is soluble in seawater. Approximately 5-6% dissolves very rapidly ( < 0.6 hr). An additional 3-4% dissolves within 60 hr. This bimodal dissolution of aerosol aluminum of crustal origin suggests that this aluminum is present in two forms. The rapidly dissolving fraction is likely aluminum already weathered from primary minerals, while the more slowly dissolving fraction is probably aluminum from the aluminosilicate matrix. Nearly the same amount of aerosol aluminum dissolved in artificial rain water ( pH= 5.5) in 6 hr as dissolved in seawater ( pH= 8) in 60 hr. The lower pH appears to not only increase the dissolution rate but may also increase the quantity of aerosol aluminum that dissolves. Dissolved organic matter in seawater appears to have relatively little effect on aerosol aluminum dissolution. Considering measured total aerosol aluminum fluxes, aluminum dissolution of 5-10% would constitute the major source for dissolved aluminum in surface waters of the open North Pacific. The calculated residence time of dissolved aluminum in the upper 100 m of the tropical North Pacific ranges from 2 to 6 years.

  9. The impact of atmospheric aerosols on trace metal chemistry in open ocean surface seawater: 2. Copper

    NASA Astrophysics Data System (ADS)

    Maring, H. B.; Duce, R. A.

    1989-01-01

    Atmospheric deposition contributes copper to the surface ocean. The biogeochemical importance and fate of this copper is poorly understood for open ocean regions. Atmospheric aerosols collected at Enewetak Atoll, in the tropical North Pacific, were exposed to seawater and artificial rainwater in laboratory experiments. Aerosol copper during the high-dust season at Enewetak Atoll is made up of aluminosilicate, oceanic, and possibly soil organic matter components. During the low-dust season, aerosol copper appears to be essentially all of oceanic origin. Virtually all nonaluminosilicate copper in marine aerosols collected at Enewetak is soluble in seawater. Dissolved organic matter and possibly cations in seawater increase the dissolution of aerosol copper. The net atmospheric flux of soluble copper to the tropical North Pacific near Enewetak is approximately 0.13 nmol cm-2 yr-1 out of a total net atmospheric copper flux of 0.14 nmol cm-2 yr-1. Atmospheric deposition supplies roughly the same quantity of soluble copper to tropical open North Pacific surface waters as does upwelling to eastern North Pacific surface waters. Atmospheric copper deposition, which appears to be primarily of natural origin, may be the most important input of copper to the surface waters of the central gyre of the North Pacific.

  10. Aerosol Type Constraints Required for Ocean Color Atmospheric Correction

    NASA Technical Reports Server (NTRS)

    Kahn, R.; Ahmad, Z.; Franz, B.; Massie, S.; Sayer, A.

    2014-01-01

    Organizers of the Aerosol Cloud Ecosystem (ACE) Science Working Group held a workshop at Goddard Space Flight Center June 16-18, 2014; speaker presentations will be made available on the ACE public website.

  11. A Decade of Field Changing Atmospheric Aerosol Research: Outcomes of EPA’s STAR Program

    EPA Science Inventory

    Conference: Gordon Research Conference in Atmospheric Chemistry, July 28 – August 2, 2013, VermontPresentation Type: PosterTitle: An Analysis of EPA’s STAR Program and a Decade of Field Changing Research in Atmospheric AerosolsAuthors: Kristina M. Wagstrom1,2, Sherri ...

  12. Changes in atmospheric aerosol loading retrieved from space based measurements during the past decade

    NASA Astrophysics Data System (ADS)

    Yoon, J.; Burrows, J. P.; Vountas, M.; von Hoyningen-Huene, W.; Chang, D. Y.; Richter, A.; Hilboll, A.

    2013-10-01

    Atmospheric aerosol, generated from natural and anthropogenic sources, plays a key role in regulating visibility, air quality, and acid deposition. It is directly linked to and impacts on human health. It also reflects and absorbs incoming solar radiation and thereby influences the climate change. The cooling by aerosols is now recognized to have partly masked the atmospheric warming from fossil fuel combustion emissions. The role and potential management of short-lived climate pollutants such as aerosol are currently a topic of much scientific and public debate. Our limited knowledge of atmospheric aerosol and its influence on the Earth's radiation balance has a significant impact on the accuracy and error of current predictions of the future global climate change. In the past decades, environmental legislation in industrialized countries has begun to limit the release of anthropogenic pollutants. In contrast, in Asia as a result of the recent rapid economic development, emissions from industry and traffic have increased dramatically. In this study, the temporal changes/trends of atmospheric aerosols, derived from the satellite instruments MODIS (on board Terra and Aqua), MISR (Terra), and SeaWiFS (OrbView-2) during the past decade, are investigated. Whilst the aerosol optical thickness, AOT, over Western Europe decreases (i.e. by up to about -40% from 2003 to 2008) and parts of North America, a statistically significant increase (about +34% in the same period) over East China is observed and attributed to both the increase in industrial output and the Asian desert dust.

  13. Lidar measurements of wildfire smoke aerosols in the atmosphere above Sofia, Bulgaria

    NASA Astrophysics Data System (ADS)

    Peshev, Zahary Y.; Deleva, Atanaska D.; Dreischuh, Tanja N.; Stoyanov, Dimitar V.

    2016-01-01

    Presented are results of lidar measurements and characterization of wildfire caused smoke aerosols observed in the atmosphere above the city of Sofia, Bulgaria, related to two local wildfires raging in forest areas near the city. A lidar systems based on a frequency-doubled Nd:YAG laser operated at 532 nm and 1064 nm is used in the smoke aerosol observations. It belongs to the Sofia LIDAR Station (at Laser Radars Laboratory, Institute of Electronics, Bulgarian Academy of Sciences), being a part of the European Aerosol Lidar Network. Optical, dynamical, microphysical, and geometrical properties and parameters of the observed smoke aerosol particles and layers are displayed and analyzed, such as: range/height-resolved profiles of the aerosol backscatter coefficient; integral aerosol backscattering; sets of colormaps displaying time series of the height distribution of the aerosol density; topologic, geometric, and volumetric properties of the smoke aerosol layers; time-averaged height profiles of backscatter-related Ångström exponent (BAE). Obtained results of retrieving and profiling smoke aerosols are commented in their relations to available meteorological and air-mass-transport forecasting and modelling data.

  14. Formic Sulfuric Anhydride: a New Chemical Species with Possible Implications for Atmospheric Aerosol

    NASA Astrophysics Data System (ADS)

    Mackenzie, Becca; Dewberry, Chris; Leopold, Ken

    2015-06-01

    Aerosols are important players in the Earth's atmosphere, affecting climate, cloud formation, and human health. In this work, we report the discovery of a previously unknown molecule, formic sulfuric anhydride (FSA), that may influence the formation and composition of atmospheric aerosol particles. Five isotopologues of FSA have been observed by microwave spectroscopy and further characterized using DFT calculations. The system has dipole moment components along all three inertial axes, and indeed a, b, and c-type transitions have been observed. A π2 + π2 + σ2 cycloaddition reaction between SO3 and HCOOH is proposed as a possible mechanism for the formation of FSA and calculations indicate that the transformation is effectively barrierless. Facile formation of the anhydride followed by hydrolysis in small water-containing clusters or liquid droplets may provide a mechanism of incorporating volatile organics into atmospheric aerosol. We suggest that FSA and its derivatives be considered in future atmospheric and climate models.

  15. Size matters in the water uptake and hygroscopic growth of atmospherically relevant multicomponent aerosol particles.

    PubMed

    Laskina, Olga; Morris, Holly S; Grandquist, Joshua R; Qin, Zhen; Stone, Elizabeth A; Tivanski, Alexei V; Grassian, Vicki H

    2015-05-14

    Understanding the interactions of water with atmospheric aerosols is crucial for determining the size, physical state, reactivity, and climate impacts of this important component of the Earth's atmosphere. Here we show that water uptake and hygroscopic growth of multicomponent, atmospherically relevant particles can be size dependent when comparing 100 nm versus ca. 6 μm sized particles. It was determined that particles composed of ammonium sulfate with succinic acid and of a mixture of chlorides typical of the marine environment show size-dependent hygroscopic behavior. Microscopic analysis of the distribution of components within the aerosol particles show that the size dependence is due to differences in the mixing state, that is, whether particles are homogeneously mixed or phase separated, for different sized particles. This morphology-dependent hygroscopicity has consequences for heterogeneous atmospheric chemistry as well as aerosol interactions with electromagnetic radiation and clouds.

  16. Effect of aerosol variation on radiance in the earth's atmosphere-ocean system.

    NASA Technical Reports Server (NTRS)

    Plass, G. N.; Kattawar, G. W.

    1972-01-01

    Calculation of the radiance at the top and bottom of the atmosphere with a realistic model of both the atmosphere and ocean. It is found that the upward flux at the top of the atmosphere, as well as the angular distribution of the radiation, changes appreciably as the aerosol amount increases from normal to ten times normal. At the same time, the upward and downward radiance just above the ocean surface undergoes important changes. The radiance does not change appreciably with variations in the aerosol distribution with height so long as the total aerosol amount remains constant. Similarly, changes in the ozone amount cause only small changes in the radiance at the wavelengths considered (0.7, 0.9, and 1.67 micron). Very little radiation returns to the atmosphere from the ocean at 0.9 and 1.67 micron because of the high absorption of water at these wavelengths.

  17. Surfactants in the sea-surface microlayer and atmospheric aerosol around the southern region of Peninsular Malaysia.

    PubMed

    Jaafar, Shoffian Amin; Latif, Mohd Talib; Chian, Chong Woan; Han, Wong Sook; Wahid, Nurul Bahiyah Abd; Razak, Intan Suraya; Khan, Md Firoz; Tahir, Norhayati Mohd

    2014-07-15

    This study was conducted to determine the composition of surfactants in the sea-surface microlayer (SML) and atmospheric aerosol around the southern region of the Peninsular Malaysia. Surfactants in samples taken from the SML and atmospheric aerosol were determined using a colorimetric method, as either methylene blue active substances (MBAS) or disulphine blue active substances (DBAS). Principal component analysis with multiple linear regressions (PCA-MLR), using the anion and major element composition of the aerosol samples, was used to determine possible sources of surfactants in atmospheric aerosol. The results showed that the concentrations of surfactants in the SML and atmospheric aerosol were dominated by anionic surfactants and that surfactants in aerosol were not directly correlated (p>0.05) with surfactants in the SML. Further PCA-MLR from anion and major element concentrations showed that combustion of fossil fuel and sea spray were the major contributors to surfactants in aerosol in the study area.

  18. Aerosols in the Convective Boundary Layer: Radiation Effects on the Coupled Land-Atmosphere System

    NASA Astrophysics Data System (ADS)

    Barbaro, E.; Vila-Guerau Arellano, J.; Ouwersloot, H. G.; Schroter, J.; Donovan, D. P.; Krol, M. C.

    2013-12-01

    We investigate the responses of the surface energy budget and the convective boundary-layer (CBL) dynamics to the presence of aerosols using a combination of observations and numerical simulations. A detailed observational dataset containing (thermo)dynamic variables observed at CESAR (Cabauw Experimental Site for Atmospheric Research) and aerosol information from the European Integrated Project on Aerosol, Cloud, Climate, and Air Quality Interactions (IMPACT/EUCAARI) campaign is employed to design numerical experiments reproducing two prototype clear-sky days characterized by: (i) a well-mixed residual layer above a ground inversion and (ii) a continuously growing CBL. A large-eddy simulation (LES) model and a mixed-layer (MXL) model, both coupled to a broadband radiative transfer code and a land-surface model, are used to study the impacts of aerosol scattering and absorption of shortwave radiation on the land-atmosphere system. We successfully validate our model results using the measurements of (thermo)dynamic variables and aerosol properties for the two different CBL prototypes studied here. Our findings indicate that in order to reproduce the observed surface energy budget and CBL dynamics, information of the vertical structure and temporal evolution of the aerosols is necessary. Given the good agreement between the LES and the MXL model results, we use the MXL model to explore the aerosol effect on the land-atmosphere system for a wide range of optical depths and single scattering albedos. Our results show that higher loads of aerosols decrease irradiance, imposing an energy restriction at the surface. Over the studied well-watered grassland, aerosols reduce the sensible heat flux more than the latent heat flux. As a result, aerosols increase the evaporative fraction. Moreover, aerosols also delay the CBL morning onset and anticipate its afternoon collapse. If also present above the CBL during the morning transition, aerosols maintain a persistent near

  19. Exploration of the link between Emiliania huxleyi bloom dynamics and aerosol fluxes to the lower Atmosphere

    NASA Astrophysics Data System (ADS)

    Trainic, M.

    2013-12-01

    Phytoplankton blooms are responsible for about 50% of the global photosynthesis, thus are a key component of the major nutrient cycles in the ocean. These blooms can be a significant source for flux of volatiles and aerosols, affecting physical chemical processes in the atmosphere. One of the most widely distributed and abundant phytoplankton species in the oceans is the coccolithophore Emiliania huxleyi. In this research, we explore the influence of the different stages of E. huxleyi bloom on the emission of primary aerosols. For this purpose, we conducted a series of controlled lab experiments to measure aerosol emissions during the growth of E. huxleyi. The cultures were grown in a specially designed growth chamber, and the aerosols were generated in a bubbling system. We collected the emitted aerosol particles on filters, and conducted a series of analysis. Scanning electron microscopy (SEM) analysis of the aerosols emitted from E.huxleyi 1216 cultures demonstrate emission of CaCO3 platelets from their exoskeleton into the air, while coccolithophores cells were absent. The results suggest that while healthy coccolithophore cells are too heavy to aerosolize, during cell lysis the coccoliths shed from the coccolithophore cells are emitted into the atmosphere. Therefore, aerosol production during bloom demise may be greater than from healthy E.huxleyi populations. We also investigated the size distribution of the aerosols at various stages of E. huxleyi growth. The presence of calcified cells greatly effects the size distribution of the emitted aerosol population. This work motivated us to explore aerosols emitted during E. huxleyi spring bloom, in a laboratory we constructed onboard the R/V Knorr research vessel, as part of the North Atlantic Virus Infection of Coccolithophore Expedition (June-July 2012). These results have far-reaching implications on the effect of E. huxleyi bloom dynamics on aerosol properties. We not only show that the E. huxleyi calcite

  20. Multi-Decadal Variations of Atmospheric Aerosols and Their Effects on Surface Radiation Trends

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Wild, Martin; Qian, Yun; Yu, Hongbin; Streets, David; Bian, Huisheng; Wang, Weiguo

    2010-01-01

    We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007, during which a suite of aerosol data from satellite observations, ground-based measurements, and intensive field experiments have become available. We analyze the long-term global and regional aerosol trends and their relationship to the changes of aerosol and precursor emissions and assess the role aerosols play in the multi-decadal change of solar radiation reaching the surface (known as "dimming" or "brightening") at different regions of the world.

  1. Assessing the impact of atmospheric stability on locally and remotely sourced aerosols at Richmond, Australia, using Radon-222

    NASA Astrophysics Data System (ADS)

    Crawford, Jagoda; Chambers, Scott; Cohen, David; Williams, Alastair; Griffiths, Alan; Stelcer, Eduard

    2016-02-01

    A flexible radon-based scheme for the classification of nocturnal stability regimes was used for the interpretation of daily-integrated PM2.5 aerosol observations collected at Richmond, Australia, between 2007 and 2011. Source fingerprint concentrations for the dominant locally and remotely sourced aerosols were analysed by nocturnal radon stability category to characterise the influences of day-to-day changes in daily integrated atmospheric mixing. The fingerprints analysed included: smoke, vehicle exhaust, secondary sulfate and aged industrial sulfur. The largest and most consistent stability influences were observed on the locally sourced pollutants. Based on a 5-year composite, daily integrated concentrations of smoke were almost a factor of 7 higher when nocturnal conditions were classed as "stable" than when they were "near neutral". For vehicle emissions a factor of 4 was seen. However, when the winter months were considered in isolation, it was found that these factors increased to 11.5 (smoke) and 5.5 (vehicle emissions) for daily average concentrations. The changes in concentration of the remotely sourced pollutants with atmospheric stability were comparatively small and less consistent, probably as a result of the nocturnal inversion frequently isolating near-surface observations from non-local sources at night. A similar classification was performed using the commonly-adopted Pasquill-Gifford (PG) stability typing technique based on meteorological parameters. While concentrations of fingerprints associated with locally-sourced pollutants were also shown to be positively correlated with atmospheric stability using the PG classification, this technique was found to underestimate peak pollutant concentrations under stable atmospheric conditions by almost a factor of 2.

  2. Atmospheric aerosols versus greenhouse gases in the twenty-first century.

    PubMed

    Andreae, Meinrat O

    2007-07-15

    Looked at in a simplistic way, aerosols have counteracted the warming effects of greenhouse gases (GHG) over the past century. This has not only provided some 'climate protection', but also prevented the true magnitude of the problem from becoming evident. In particular, it may have resulted in an underestimation of the sensitivity of the climate system to the effect of GHG. Over the present century, the role of aerosols in opposing global warming will wane, as there are powerful policy reasons to reduce their emissions and their atmospheric lifetimes are short in contrast to those of the GHG. On the other hand, aerosols will continue to play a role in regional climate change, especially with regard to the water cycle. The end of significant climate protection by atmospheric aerosols, combined with the potentially very high sensitivity of the climate system, makes sharp and prompt reductions in greenhouse gas emissions, especially CO2, very urgent.

  3. Impact of Aerosols on Atmospheric Attenuation Loss in Central Receiver Systems: Preprint

    SciTech Connect

    Sengupta, M.; Wagner, M. J.

    2011-08-01

    Atmospheric attenuation loss between the heliostat field and receiver has been recognized as a significant source of loss in Central Receiver Systems. In clear sky situations, extinction of Direct Normal Irradiance (DNI) is primarily by aerosols in the atmosphere. When aerosol loading is high close to the surface the attenuation loss between heliostat and receivers is significantly influenced by the amount of aerosols present on a particular day. This study relates measured DNI to aerosol optical depths close to the surface of the earth. The model developed in the paper uses only measured DNI to estimate the attenuation between heliostat and receiver in a central receiver system. The requirement that only a DNI measurement is available potentially makes the model a candidate for widespread use.

  4. A global average model of atmospheric aerosols for radiative transfer calculations

    NASA Technical Reports Server (NTRS)

    Toon, O. B.; Pollack, J. B.

    1976-01-01

    A global average model is proposed for the size distribution, chemical composition, and optical thickness of stratospheric and tropospheric aerosols. This aerosol model is designed to specify the input parameters to global average radiative transfer calculations which assume the atmosphere is horizontally homogeneous. The model subdivides the atmosphere at multiples of 3 km, where the surface layer extends from the ground to 3 km, the upper troposphere from 3 to 12 km, and the stratosphere from 12 to 45 km. A list of assumptions made in construction of the model is presented and discussed along with major model uncertainties. The stratospheric aerosol is modeled as a liquid mixture of 75% H2SO4 and 25% H2O, while the tropospheric aerosol consists of 60% sulfate and 40% soil particles above 3 km and of 50% sulfate, 35% soil particles, and 15% sea salt below 3 km. Implications and consistency of the model are discussed.

  5. Two-wavelength lidar characterization of atmospheric aerosol fields at low altitudes over heterogeneous terrain

    NASA Astrophysics Data System (ADS)

    Peshev, Zahary Y.; Dreischuh, Tanja N.; Toncheva, Eleonora N.; Stoyanov, Dimitar V.

    2012-01-01

    The possibilities for applying multiwavelength elastic lidar probing of the atmosphere to help monitor air-quality over large industrial and densely populated areas, based predominantly on the use and analysis of commonly obtainable backscatter-related lidar quantities, are examined. Presented are two-wavelength (1064/532 nm) lidar observations on the spatial distribution, structure, composition, and temporal evolution of close-to-surface atmospheric aerosol fields over heterogeneous orographic areas (adjacent city, plain, and mountain) near Sofia, Bulgaria. Selected winter-time evening lidar measurements are described. Range profiles, histograms, and evolutional range-time diagrams of the aerosol backscatter coefficients, range-corrected lidar signals, normalized standard deviations, and backscatter-related Ångström exponents (BAE) are analyzed. Near-perfect correlation between the aerosol density distribution and orographic differentiation of the underlying terrain is established, finding expression in a sustained horizontal stratification of the probed atmospheric domains. Distinctive features in the spatial distribution and temporal evolution of both the fine- and coarse aerosol fractions are revealed in correlation with terrain's orography. Zonal aerosol particle size distributions are qualitatively characterized by using an approach based on BAE occurrence frequency distribution analysis. Assumptions are made about the aerosol particle type, origin, and dominating size as connected (by transport-modeling data) to local pollution sources. Specifics and patterns of temporal dynamics of the fine- and coarse aerosol fraction density distributions and movements, revealed by using statistical analysis of lidar data, are discussed. The obtained results prove the capability of the used two-wavelength lidar approach to perform fast-, reliable, and self-consistent characterization of important optical-, micro-physical-, and dynamical properties of atmospheric

  6. Subarctic atmospheric aerosol composition: 2. Hygroscopic growth properties

    SciTech Connect

    Herich, Hanna; Kammermann, Lukas; Friedman, Beth; Gross, Deborah S.; Weingartner, E.; Lohmann, U.; Spichtinger, Peter; Gysel, Martin; Baltensperger, Urs; Cziczo, Daniel J.

    2009-07-10

    Sub-arctic aerosols were sampled during July 2007 at the Abisko Scientific Research Station Stordalen site in northern Sweden with an instrument setup consisting of a custom-built Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA) connected in series to a single particle mass spectrometer. Aerosol chemical composition in the form of bipolar single particle mass spectra was determined as a function of hygroscopic growth both in situ and in real time. The HTDMA was deployed at a relative humidity of 82% and particles with a dry mobility diameter of 260 nm were selected. Aerosols from two distinct airmasses were analyzed during the sampling period. Sea salt aerosols were found to be the dominant particle group with the highest hygroscopicity. High intensities of sodium and related peaks in the mass spectra were identified as exclusive markers for large hygroscopic growth. Particles from biomass combustion were found to be the least hygroscopic aerosol category. Species normally considered soluble (e.g., sulfates and nitrates) were found in particles ranging from high to low hygroscopicity. Furthermore, the signal intensities of the peaks related to these species did not correlate with hygroscopicity.

  7. Influence of the external mixing state of atmospheric aerosol on derived CCN number concentrations

    NASA Astrophysics Data System (ADS)

    Wex, H.; McFiggans, G.; Henning, S.; Stratmann, F.

    2010-05-01

    We derived the range of particle hygroscopicities ($\\kappa$) that occurs in the atmosphere, based on literature data of measured hygroscopic growth or based on chemical composition. The derived $\\kappa$-values show that the atmospheric aerosol often is an external mixture with respect to hygroscopicity. Mean $\\kappa$ were derived for urban, rural, and marine aerosols for the different hygroscopic modes. Using these $\\kappa$ and exemplary particle number size distributions for the different aerosols, the number concentration of cloud condensation nuclei (NCCN) was derived for two cases, (1) accounting for the less hygroscopic fraction of particles and (2) assuming all particles to have $\\kappa$ of the more hygroscopic mode. NCCN derived from measured particle hygroscopicity is overestimated for case (2). Overestimation of NCCN is largest for fresh continental aerosol and less pronounced for marine aerosol. With $\\kappa$ derived from bulk aerosol composition data, only the hygroscopicity of more soluble aerosol particles is captured. Bulk or even size-resolved composition data will be insufficient to predict NCCN under many conditions unless independent information about particle mixing state is available.

  8. Predictions of the electrical conductivity and charging of the aerosols in Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    Borucki, W. J.; Levin, Z.; Whitten, R. C.; Keesee, R. G.; Summers, A. L.; Toon, O. B.; Dubach, J.

    1987-01-01

    Computational results are given for Titan atmosphere aerosol electrical conductivity and charge at altitudes up to 400 km, together with a consideration of ionization from such sources as galactic cosmic rays and electron precipitation from the Saturnian magnetosphere. Predicted conductivity shows the existence of substantial electron concentrations up to the Titan surface. At altitudes of more than 100 km, and aerosol concentrations greater than 10/cu cm, electron/positive ion-recombination is found to be controlled by the recombination of the aerosols' surfaces rather than by the gas-kinetic recombination rate.

  9. Regional behaviour of atmospheric aerosols over Indo-Gangetic Basin during pre-monsoon

    NASA Astrophysics Data System (ADS)

    Tiwari, S.; Singh, A. K.

    2013-05-01

    Atmospherics aerosols play a vital role in the field of study of Earth's radiation budget and their impact on climate change. The present study was carried out for the study of variation of aerosol characteristics during pre-monsoon season 2011 at different locations, (a) Jaipur (26.900 N, 75.900E), (b) Kanpur (26.40 N, 80.40 E) and (c) Gandhi College, Ballia (25.8° N, 84.2°E) over Indo Gangetic Basin (IGB) using AERONET level 1.5 data. Various interesting results are discussed in present paper in terms of aerosol optical and radiative properties.

  10. Infrared spectroscopy of homogeneously nucleated hydrazine aerosols - Disordered and crystalline phases. [in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Dunder, T.; Clapp, M. L.; Miller, R. E.

    1993-01-01

    It is shown that aerosols generated at low temperatures and high condensation rate spontaneously form in a highly crystalline state. The resonant absorption bands in the IR spectra of these highly crystalline particles are much sharper than any reported previously in the bulk, and reveal details in the N-H vibrational bands that have not been previously observed. A disordered phase is also observed at somewhat higher temperatures. These results are consistent with this being a supercooled liquid. The fact that the spectra associated with these two aerosol phases are quite different is important to any future attempts at detecting hydrazine aerosols in planetary atmospheres by remote sensing techniques.

  11. Aerosol physical, chemical and optical properties observed in the ambient atmosphere during haze pollution conditions

    NASA Astrophysics Data System (ADS)

    Li, Zhengqiang; Xie, Yisong; Li, Donghui; Li, Kaitao; Zhang, Ying; Li, Li; Lv, Yang; Qie, Lili; Xu, Hua

    Aerosol’s properties in the ambient atmosphere may differ significantly from sampling results due to containing of abundant water content. We performed sun-sky radiometer measurements in Beijing during 2011 and 2012 winter to obtain distribution of spectral and angular sky radiance. The measurements are then used to retrieve aerosol physical, chemical and optical properties, including single scattering albedo, size distribution, complex refractive indices and aerosol component fractions identified as black carbon, brown carbon, mineral dust, ammonium sulfate-like components and water content inside particle matters. We found that during winter haze condition aerosol is dominated by fine particles with center radius of about 0.2 micron. Fine particles contribute about 93% to total aerosol extinction of solar light, and result in serious decrease of atmospheric visibility during haze condition. The percentage of light absorption of haze aerosol can up to about 10% among its total extinction, much higher than that of unpolluted conditions, that causes significant radiative cooling effects suppressing atmospheric convection and dispersion of pollutants. Moreover, the average water content occupies about one third of the ambient aerosol in volume which suggests the important effect of ambient humidity in the formation of haze pollution.

  12. Monitoring of Sahelian aerosol and Atmospheric water vapor content characteristics from sun photometer measurements

    NASA Astrophysics Data System (ADS)

    Faizoun, C. A.; Podaire, A.; Dedieu, G.

    1994-11-01

    Atmospheric measurements in two Sahelian sites in West Africa are presented and analyzed. The measurements were performed using a sun photometer with five bands in the visible and near-infrared range of the solar spectrum. This instrument measures spectral values of the solar irradiances that are used to derive the aerosol optical thickness in three bands; the two other bands are used to derive the integrated atmospheric water vapor content using a differential absorption method. The Angstroem exponent, which is an estimate of the aerosol particle size, is derived from the spectral dependence of the optical thickness. Although the sites were located far from Sahara Desert aerosol sources, the observed aerosol optical thicknesses were high, with a mean annual value of 0.5 at 550 nm. The spectral dependence of aerosol optical thickness is generally low, with a mean annual value of Angstroem exponent of 0.4. The aerosol optical thickness and the atmosphereic water vapor content are both characterized by high temporal variability and exhibit seasonal cycles. From these measurements, climatological values and associated probability distribution laws are proposed.

  13. Characterising Biomass Burning Aerosol in WRF-Chem using the Volatility Basis Set, with Evaluation against SAMBBA Flight Data

    NASA Astrophysics Data System (ADS)

    Lowe, D.; Topping, D. O.; Archer-Nicholls, S.; Darbyshire, E.; Morgan, W.; Liu, D.; Allan, J. D.; Coe, H.; McFiggans, G.

    2015-12-01

    The burning of forests in the Amazonia region is a globally significant source of carbonaceous aerosol, containing both absorbing and scattering components [1]. In addition biomass burning aerosol (BBA) are also efficient cloud condensation nuclei (CCN), modifying cloud properties and influencing atmospheric circulation and precipitation tendencies [2]. The impacts of BBA are highly dependent on their size distribution and composition. A bottom-up emissions inventory, the Brazilian Biomass Burning Emissions Model (3BEM) [3], utilising satellite products to generate daily fire emission maps is used. Injection of flaming emissions within the atmospheric column is simulated using both a sub-grid plume-rise parameterisation [4], and simpler schemes, within the Weather Research and Forecasting Model with Chemistry (WRF-Chem, v3.4.1) [5]. Aerosol dynamics are simulated using the sectional MOSAIC scheme [6], incorporating a volatility basis set (VBS) treatment of organic aerosol [7]. For this work we have modified the 9-bin VBS to use the biomass burning specific scheme developed by May et al. [8]. The model has been run for September 2012 over South America (at a 25km resolution). We will present model results evaluating the modelled aerosol vertical distribution, size distribution, and composition against measurements taken by the FAAM BAe-146 research aircraft during the SAMBBA campaign. The main focus will be on investigating the factors controlling the vertical gradient of the organic mass to black carbon ratio of the measured aerosol. This work is supported by the Nature Environment Research Council (NERC) as part of the SAMBBA project under grant NE/J010073/1. [1] D. G. Streets et al., 2004, J. Geophys. Res., 109, D24212. [2] M. O. Andreae et al., 2004, Science, 303, 1337-1342. [3] K. Longo et al., 2010, Atmos. Chem. Phys., 10, 5,785-5,795. [4] S. Freitas et al., 2007, Atmos. Chem. Phys., 7, 3,385-3,398. [5] S. Archer-Nicholls et al., 2015, Geosci. Model Dev., 8

  14. Characterising the atmosphere of a uniquely low-density, sub-Saturn mass planet

    NASA Astrophysics Data System (ADS)

    Spake, Jessica; Anderson, D.; Barstow, J.; Evans, T.; Gillon, M.; Hebrardr, G.; Hellier, C.; Kataria, T.; Lam, K.; Nikolov, N.; Sing, D.; Triaud, A.; Wakeford, H.

    2016-08-01

    We propose to use HST and Spitzer to measure the transmission spectrum of the recently discovered, hot sub-Saturn mass exoplanet WASP-127b. Its low mass (0.19 Mj) and large radius (1.39 Rj) give it the lowest density of any exoplanet with a radial velocity measured mass. It has the largest predicted atmospheric scale height of any planet, and orbits a bright (V~10.2) star, making it an exceptional target for atmospheric characterisation via transmission spectroscopy. With HST and Spitzer, we will measure the full transmission spectrum from 0.3 to 5 microns, covering water, sodium, and potassium absorption features, and scattering by molecular hydrogen or haze. The Spitzer transit photometry at 3.6 and 4.5 microns will be used alongside the HST spectrum to break the low abundance/cloud degeneracy which prevents constraints being made on atmospheric metallicity. With a low mass of 0.19 Mj, this planet sits in an unexplored mass range at the very low-end of gas giant planets, making WASP-127b strategecally important for constraining the planetary mass-metallicity relationship, which is important for understanding planet formation mechanisms.

  15. [Development of a photoacoustic spectroscopy system for the measurement of absorption coefficient of atmospheric aerosols].

    PubMed

    Liu, Qiang; Niu, Ming-Sheng; Wang, Gui-Shi; Cao, Zhen-Song; Liu, Kun; Chen, Wei-Dong; Gao, Xiao-Ming

    2013-07-01

    In the present paper, the authors focus on the effect of the resonance frequency shift due to the changes in temperature and humidity on the PA signal, present several methods to control the noise derived form gas flow and vibration from the sampling pump. Based on the efforts mentioned above, a detection limit of 1.4 x 10(-8) W x cm(-1) x Hz(-1/2) was achieved for the measurement of atmospheric aerosols absorption coefficient. During the experiments, the PA cell was calibrated with the absorption of standard NO2 gas at 532 nm and the atmospheric aerosols were measured continuously. The measurement results show that the PAS is suitable for the real-time measurement of the absorption coefficient of atmospheric aerosols in their natural suspended state.

  16. Characterisation of local and external contributions of atmospheric particulate matter at a background coastal site

    NASA Astrophysics Data System (ADS)

    Salvador, Pedro; Artíñano, Begoña; Querol, Xavier; Alastuey, Andrés; Costoya, Miguel

    This study applies a methodology for discriminating local and external contributions of atmospheric particulate matter (PM) at a rural background station in the North-western coast of Spain. The main inputs at the nearest scale have come from soil dust, marine aerosol and road traffic. At a larger scale, the highest contributions have come from fossil-fuel combustion sources, giving rise to relatively high ammonium sulphate background levels, mainly in summer. External contributions from long-range transport processes of African dust and nitrate have been detected. Morocco and Western Sahara have been identified as the main potential source regions of African dust, with a higher content of Al and Ti than other crustal components. Geographical areas from central and Eastern Europe have been identified as potential sources of particulate nitrate. The discrimination of the PM contribution from natural and anthropogenic sources at different geographical scales is a necessary information for establishing PM reduction strategies in specific areas.

  17. Temporal and spatial variation of morphological descriptors for atmospheric aerosols collected in Mexico City

    NASA Astrophysics Data System (ADS)

    China, S.; Mazzoleni, C.; Dubey, M. K.; Chakrabarty, R. K.; Moosmuller, H.; Onasch, T. B.; Herndon, S. C.

    2010-12-01

    We present an analysis of morphological characteristics of atmospheric aerosol collected during the MILAGRO (Megacity Initiative: Local and Global Research Observations) field campaign that took place in Mexico City in March 2006. The sampler was installed on the Aerodyne mobile laboratory. The aerosol samples were collected on nuclepore clear polycarbonate filters mounted in Costar pop-top membrane holders. More than one hundred filters were collected at different ground sites with different atmospheric and geographical characteristics (urban, sub-urban, mountain-top, industrial, etc.) over a month period. Selected subsets of these filters were analyzed for aerosol morphology using a scanning electron microscope and image analysis techniques. In this study we investigate spatial and temporal variations of aerosol shape descriptors, morphological parameters, and fractal dimension. We also compare the morphological results with other aerosol measurements such as aerosol optical properties(scattering and absorption) and size distribution data. Atmospheric aerosols have different morphological characteristics depending on many parameters such as emission sources, atmospheric formation pathways, aging processes, and aerosol mixing state. The aerosol morphology influences aerosol chemical and mechanical interactions with the environment, physical properties, and radiative effects. In this study, ambient aerosol particles have been classified in different shape groups as spherical, irregularly shaped, and fractal-like aggregates. Different morphological parameters such as aspect ratio, roundness, feret diameter, etc. have been estimated for irregular shaped and spherical particles and for different kinds of soot particles including fresh soot, collapsed and coated soot. Fractal geometry and image processing have been used to obtain morphological characteristics of different soot particles. The number of monomers constituting each aggregate and their diameters were

  18. An Energetic Perspective on Aerosol Radiative Forcing and Interactions with Atmospheric Wave Activity

    NASA Astrophysics Data System (ADS)

    Hosseinpour, F.; Wilcox, E. M.; Colarco, P. R.

    2014-12-01

    Aerosols have the capability to alter regional-scale atmospheric circulations. A better understanding of the contribution of aerosols to multi-scale atmospheric phenomena and their transient changes is crucial for efforts to evaluate climate predictions using next generation climate models. In this study we address the following questions: (1) Is there a mechanistic relationship between variability of oceanic dust aerosol forcing and transient changes in the African easterly jet- African easterly wave (AEJ-AEW) system? (2) What are the long-term impacts of possible aerosol-wave interactions on climate dynamics of eastern tropical Atlantic Ocean and western African monsoon (WAM) region during boreal summer seasons? Our hypothesis is that aerosol radiative forcing may act as additional energy source to fuel the development of African easterly waves on the northern and southern sides of the AEJ. Evidence in support of this hypothesis is presented based on analysis of an ensemble of NASA satellite data sets, including aerosol optical thickness (AOT) observations from the Moderate Resolution Imaging Spectro-radiometer (MODIS) and the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS), as well as an atmospheric reanalysis from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) and a simulation of global aerosol distributions made with the Goddard Earth Observing System Model version 5 (GEOS-5) Earth system model with meteorology constrained by MERRA and an assimilation of MODIS AOT (MERRAero). We propose that the impacts of Saharan aerosols on the regional climate dynamics occur through contributions to the eddy energy of waves with 2—7-day and 7—11-day variability.

  19. Incremental Reactivity Effects on Secondary Organic Aerosol Formation in Urban Atmospheres with and without Biogenic Influence

    NASA Astrophysics Data System (ADS)

    Kacarab, Mary; Li, Lijie; Carter, William P. L.; Cocker, David R., III

    2016-04-01

    Two different surrogate mixtures of anthropogenic and biogenic volatile organic compounds (VOCs) were developed to study secondary organic aerosol (SOA) formation at atmospheric reactivities similar to urban regions with varying biogenic influence levels. Environmental chamber simulations were designed to enable the study of the incremental aerosol formation from select anthropogenic (m-Xylene, 1,2,4-Trimethylbenzene, and 1-Methylnaphthalene) and biogenic (α-pinene) precursors under the chemical reactivity set by the two different surrogate mixtures. The surrogate reactive organic gas (ROG) mixtures were based on that used to develop the maximum incremental reactivity (MIR) factors for evaluation of O3 forming potential. Multiple incremental aerosol formation experiments were performed in the University of California Riverside (UCR) College of Engineering Center for Environmental Research and Technology (CE-CERT) dual 90m3 environmental chambers. Incremental aerosol yields were determined for each of the VOCs studied and compared to yields found from single precursor studies. Aerosol physical properties of density, volatility, and hygroscopicity were monitored throughout experiments. Bulk elemental chemical composition from high-resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) data will also be presented. Incremental yields and SOA chemical and physical characteristics will be compared with data from previous single VOC studies conducted for these aerosol precursors following traditional VOC/NOx chamber experiments. Evaluation of the incremental effects of VOCs on SOA formation and properties are paramount in evaluating how to best extrapolate environmental chamber observations to the ambient atmosphere and provides useful insights into current SOA formation models. Further, the comparison of incremental SOA from VOCs in varying surrogate urban atmospheres (with and without strong biogenic influence) allows for a unique perspective on the impacts

  20. Characterization of Organic Nitrogen in the Atmosphere Using High Resolution Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ge, X.; Sun, Y.; Chen, M.; Zhang, Q.

    2015-12-01

    Despite extensive efforts on characterizing organic nitrogen (ON) compounds in atmospheric aerosols and aqueous droplets, knowledge of ON chemistry is still limited, mainly due to its chemical complexity and lack of highly time-resolved measurements. This work is aimed at optimizing the method of using Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-AMS) to characterize ON compounds in atmospheric aerosols. Seventy-five pure nitrogen-containing organic compounds covering a variety of functional groups were analyzed with the HR-AMS. Our results show that ON compounds commonly produce NHx+, NOx+, which are usually attributed to inorganic N species such as ammonium and nitrate, and CH2N+ at m/z = 28, which is rarely quantified in ambient aerosol due to large interference from N2+ in the air signal. As a result, using the nitrogen-to-carbon (N/C) calibration factor proposed by Aiken et al. (2008) on average leads to ~ 20% underestimation of N/C in ambient organic aerosol. A new calibration factor of 0.79 is proposed for determining the average N/C in organics. The relative ionization efficiencies (RIEs) of different ON species, on average, are found to be consistent with the default RIE value (1.4) for the total organics. The AMS mass spectral features of various types of ON species (amines, amides, amino acids, etc.) are examined and used for characterizing ON composition in ambient aerosols. Our results indicate that submicron organic aerosol measured during wintertime in Fresno, CA contains significant amounts of amino-compounds whereas more diversified ON species, including N-containing aromatic heterocycle (e.g., imidazoles), are observed in fog waters collected simultaneously. Our findings have important implications for understanding atmospheric ON behaviors via the widespread HR-AMS measurements of ambient aerosols and droplets.

  1. Resources of the ionized atmosphere as an aerosol source

    NASA Astrophysics Data System (ADS)

    Smirnov, V. V.; Savchenko, A. V.

    2006-12-01

    The potential resources on the ion-stimulated syntheses effects of aerosol particles of lower troposphere in test sites in the arctic, mountain, arid and forest areas as the function of irradiation time and gas-precursor concentration were experimentally and theoretically evaluated. The dust-free outdoor air was irradiated with an ionization current of 10 - 6 A by α-rays from isotope 239Pu. The total output of radiolytic aerosols (RA) with a diameter of 3-1000 nm was found to be 0.05-0.1 molecules per 1 eV of absorbed radiation, while the physical upper limit is 0.25-0.4 molecules/eV. In an interval of exposition time from 6 to 800 s (adsorbed energy is 3 · 10 12-10 14 eV/cm 3) the RA mass concentration at different sites was increased from 1-10 to 50-500 μg/m 3. According to the liquid chromatography data the major RA material is the H 2O/HNO 3 solution with acid concentration ˜ 25%. The used physical model presents new aerosols as a product from small and intermediate ion association through formation of neutral clusters and describes adequately some of the peculiarities in field experiment data. Introducing SO 2, NH 3, and also hydrochloric, nitric and sulphuric acid vapours with concentration 0.1-1 mg/m 3 in the irradiated air stimulated an increase of mass aerosol concentration by a factor of 8-30. The mean size also decreased by a factor of 3-5. These facts allowed us to expect that the chemical composition of radiolytic aerosols generated in outdoor air would noticeably differ after addition of the gas-precursors.

  2. A photophonic instrument concept to measure atmospheric aerosol absorption. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Engle, C. D.

    1982-01-01

    A laboratory model of an instrument to measure the absorption of atmospheric aerosols was designed, built, and tested. The design was based on the photophonic phenomenon discovered by Bell and an acoustic resonator developed by Helmholtz. Experiments were done to show ways the signal amplitude could be improved and the noise reduced and to confirm the instrument was sensitive enough to be practical. The research was undertaken to develop concepts which show promise of being improvements on the instruments that are presently used to measure the absorption of the Sun's radiation by the Earth's atmospheric aerosols.

  3. Influences of upwind emission sources and atmospheric processing on aerosol chemistry and properties at a rural location in the Northeastern U.S.: URBAN INFLUENCE ON RURAL AEROSOL

    SciTech Connect

    Zhou, Shan; Collier, Sonya; Xu, Jianzhong; Mei, Fan; Wang, Jian; Lee, Yin-Nan; Sedlacek, Arthur J.; Springston, Stephen R.; Sun, Yele; Zhang, Qi

    2016-05-19

    Continuous real-time measurements of atmospheric aerosol with an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-AMS) coupled with a fast temperature-stepping thermodenuder were carried out in summer 2011 at Brookhaven National Laboratory (BNL, 40.871°N, 72.89°W) during the DOE Aerosol Life Cycle Intensive Operational Period (ALC-IOP) campaign.

  4. Atmospheric correction of ocean color imagery: use of the junge power-law aerosol size distribution with variable refractive index to handle aerosol absorption.

    PubMed

    Chomko, R M; Gordon, H R

    1998-08-20

    When strongly absorbing aerosols are present in the atmosphere, the usual two-step procedure of processing ocean color data-(1) atmospheric correction to provide the water-leaving reflectance (rho(w)), followed by (2) relating rho(w) to the water constituents-fails and simultaneous estimation of the ocean and aerosol optical properties is necessary. We explore the efficacy of using a simple model of the aerosol-a Junge power-law size distribution consisting of homogeneous spheres with arbitrary refractive index-in a nonlinear optimization procedure for estimating the relevant oceanic and atmospheric parameters for case 1 waters. Using simulated test data generated from more realistic aerosol size distributions (sums of log-normally distributed components with different compositions), we show that the ocean's pigment concentration (C) can be retrieved with good accuracy in the presence of weakly or strongly absorbing aerosols. However, because of significant differences in the scattering phase functions for the test and power-law distributions, large error is possible in the estimate of the aerosol optical thickness. The positive result for C suggests that the detailed shape of the aerosol-scattering phase function is not relevant to the atmospheric correction of ocean color sensors. The relevant parameters are the aerosol single-scattering albedo and the spectral variation of the aerosol optical depth. We argue that the assumption of aerosol sphericity should not restrict the validity of the algorithm and suggest an avenue for including colored aerosols, e.g., wind-blown dust, in the procedure. A significant advantage of the new approach is that realistic multicomponent aerosol models are not required for the retrieval of C.

  5. Hygroscopic Properties of Atmospheric Aerosol Measured with an HTDMA in an Urban Background Site in Madrid

    NASA Astrophysics Data System (ADS)

    Alonso-Blanco, E.; Gómez-Moreno, F. J.; Becerril, M.; Coz, E.; Artíñano, B.

    2015-12-01

    The observation of high aerosol hygroscopic growth in Madrid is mainly limited to specific atmospheric conditions, such as local stagnation episodes, which take place in winter time. One of these episodes was identified in December 2014 and the hygroscopic growth factor (GF) measurements obtained in such episode were analysed in order to know the influence of the meteorological conditions on aerosol hygroscopic properties. The prevailing high atmospheric stability triggered an increase of the particle total concentration during the study period, with several peaks that exceeded 4.0 104 particles cm-3, as well as an increase in the inorganic fraction of the aerosol, the NO3- concentration, which in this case corresponded to 25% of the total PM1 non-refractory composition. The aerosol hygroscopic growth distribution was bimodal during the episode, with an average GF around 1.2 for the five dry particle sizes measured and an average GF spread ≥ 0.15. In addition, it is important to note that when a reduction in the concentrations of NO3- is observed, it coincides with a decrease of the GF and its spread. These data suggest, on the one hand, a high degree of external mixing state of the aerosol during the episode and, on the other hand, a notable association between the GF and the inorganic fraction of the aerosol.

  6. Comparison of activity coefficient models for atmospheric aerosols containing mixtures of electrolytes, organics, and water

    NASA Astrophysics Data System (ADS)

    Tong, Chinghang; Clegg, Simon L.; Seinfeld, John H.

    Atmospheric aerosols generally comprise a mixture of electrolytes, organic compounds, and water. Determining the gas-particle distribution of volatile compounds, including water, requires equilibrium or mass transfer calculations, at the heart of which are models for the activity coefficients of the particle-phase components. We evaluate here the performance of four recent activity coefficient models developed for electrolyte/organic/water mixtures typical of atmospheric aerosols. Two of the models, the CSB model [Clegg, S.L., Seinfeld, J.H., Brimblecombe, P., 2001. Thermodynamic modelling of aqueous aerosols containing electrolytes and dissolved organic compounds. Journal of Aerosol Science 32, 713-738] and the aerosol diameter dependent equilibrium model (ADDEM) [Topping, D.O., McFiggans, G.B., Coe, H., 2005. A curved multi-component aerosol hygroscopicity model framework: part 2—including organic compounds. Atmospheric Chemistry and Physics 5, 1223-1242] treat ion-water and organic-water interactions but do not include ion-organic interactions; these can be referred to as "decoupled" models. The other two models, reparameterized Ming and Russell model 2005 [Raatikainen, T., Laaksonen, A., 2005. Application of several activity coefficient models to water-organic-electrolyte aerosols of atmospheric interest. Atmospheric Chemistry and Physics 5, 2475-2495] and X-UNIFAC.3 [Erdakos, G.B., Change, E.I., Pandow, J.F., Seinfeld, J.H., 2006. Prediction of activity coefficients in liquid aerosol particles containing organic compounds, dissolved inorganic salts, and water—Part 3: Organic compounds, water, and ionic constituents by consideration of short-, mid-, and long-range effects using X-UNIFAC.3. Atmospheric Environment 40, 6437-6452], include ion-organic interactions; these are referred to as "coupled" models. We address the question—Does the inclusion of a treatment of ion-organic interactions substantially improve the performance of the coupled models over

  7. Significant atmospheric aerosol pollution caused by world food cultivation

    NASA Astrophysics Data System (ADS)

    Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

    2016-05-01

    Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to its sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

  8. Significant Atmospheric Aerosol Pollution Caused by World Food Cultivation

    NASA Technical Reports Server (NTRS)

    Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

    2016-01-01

    Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to its sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

  9. Aerosol-Cloud-Radiation Interactions in Atmospheric Forecast Models

    DTIC Science & Technology

    2008-09-30

    succinic and adipic acids show no growth. Airborne measurements of hygroscopic growth factors of ship exhaust aerosol during the 2007 Marine Stratus...presented for several organic acids . Oxalic, malonic, glutaric, and glyoxylic acids grow gradually with increasing relative humidity up to 94%, while...respectively. These values agree with previously reported values for water-soluble organics such as dicarboxylic and multifunctional acids , and correspond

  10. Mass Spectrometry of Atmospheric Aerosol: 1 nanometer to 1 micron

    NASA Astrophysics Data System (ADS)

    Worsnop, D. R.; Ehn, M.; Junninen, H.; Kulmala, M. T.

    2010-12-01

    The role of aerosol particles remains the largest uncertainty in quantitatively assessing past, current and future climate change. The principal reason for that uncertainty arises from the need to characterize and model composition and size dependent aerosol processes, ranging from nanometer to micron scales. Aerosol mass spectrometry results have shown that about half the sub-micron aerosol composition is composed of highly oxygenated organics that are not well understood in terms of photochemical reaction mechanisms (Jimenez et al, 2009). This work has included application of high resolution time-of-flight mass spectrometry (ToFMS) in order to determine elemental and functional group composition of complex organic components. Recently, we have applied similar ToFMS to determine the composition of ambient ions, molecules and clusters, potentially involved in formation and growth of nano-particles (Junninen et al, 2010). Observed organic anions (molecular weight range 200-500 Th) have similar chemical composition as the least volatile secondary organics observed in fine particles; while organic cations are dominated by amines and pyridines. During nucleation events, anions are dominated by sulphuric acid cluster ions (Ehn et al, 2010). In both nanometer and micrometer size ranges, the goal to elucidate the roles of inorganic and organic species, particularly how particle evolution and physical properties depend on mixed compositions. Recent results will be discussed, including ambient and experimental chamber observations. Ehn et al, Atmos. Chem. Phys. Discuss., 10, 14897-14946, 2010 Jimenez et al, Science, 326, 1525-1529, 2009 Junninen et al, Atmos. Meas. Tech., 3, 1039-1053, 2010

  11. Aerosol-Cloud-Radiation Interactions in Atmospheric Forecast Models

    DTIC Science & Technology

    2007-09-30

    combustion, biomass burning, and biogenic activity are sources of particulate oxalic acid ; photooxidation of volatile organic compounds (VOCs...acids are likely particle-phase compounds formed by cloud and fog processing. Oxalic acid , which has also been shown to be formed by aqueous-phase...chemistry in cloud droplets, remains in the aerosol phase after subsequent droplet evaporation. In the aqueous phase, oxalic acid is formed by oxidation

  12. Formation of highly porous aerosol particles by atmospheric freeze-drying in ice clouds

    NASA Astrophysics Data System (ADS)

    Rudich, Yinon; Adler, Gabriela; Koop, Thomas; Taraniuk, Ilya; Moise, Tamar; Koren, Ilan; Heiblum, Reuven; Haspel, Carynelisa

    2014-05-01

    In cold high altitude cirrus clouds and anvils of high convective clouds in the tropics and mid-latitudes, ice partciles that are exposed to subsaturation conditions with respect to ice can sublimate, leaving behind residual modified aerosols. This freeze-drying process can occur in various types of clouds. In this talk we will describe experiements that simulate the atmospheric freeze-drying cycle of aerosols. We find that aerosols with high organic content can form highly porous particles (HPA) with a larger diameter and a lower density than the initial homogenous aerosol following ice subliation. We attribute this morphology change to phase separation upon freezing followed by a glass transition of the organic material that can preserve a porous structure follwoing ice sublimation. We find that the highly porous aerosol scatter solar light less efficiently than non-porous aerosol particles. A porous structure may explain the previously observed enhancement in ice nucleation efficiency of glassy organic particles. These observations may have implications for subsequent cloud formation cycles and aerosol albedo near cloud edges.

  13. Atmospheric aerosol deposition influences marine microbial communities in oligotrophic surface waters of the western Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Maki, Teruya; Ishikawa, Akira; Mastunaga, Tomoki; Pointing, Stephen B.; Saito, Yuuki; Kasai, Tomoaki; Watanabe, Koichi; Aoki, Kazuma; Horiuchi, Amane; Lee, Kevin C.; Hasegawa, Hiroshi; Iwasaka, Yasunobu

    2016-12-01

    Atmospheric aerosols contain particulates that are deposited to oceanic surface waters. These can represent a major source of nutrients, trace metals, and organic compounds for the marine environment. The Japan Sea and the western Pacific Ocean are particularly affected by aerosols due to the transport of desert dust and industrially derived particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) from continental Asia. We hypothesized that supplementing seawater with aerosol particulates would lead to measurable changes in surface water nutrient composition as well as shifts in the marine microbial community. Shipboard experiments in the Pacific Ocean involved the recovery of oligotrophic oceanic surface water and subsequent supplementation with aerosol particulates obtained from the nearby coastal mountains, to simulate marine particulate input in this region. Initial increases in nitrates due to the addition of aerosol particulates were followed by a decrease correlated with the increase in phytoplankton biomass, which was composed largely of Bacillariophyta (diatoms), including Pseudo-nitzschia and Chaetoceros species. This shift was accompanied by changes in the bacterial community, with apparent increases in the relative abundance of heterotrophic Rhodobacteraceae and Colwelliaceae in aerosol particulate treated seawater. Our findings provide empirical evidence revealing the impact of aerosol particulates on oceanic surface water microbiology by alleviating nitrogen limitation in the organisms.

  14. Low-molecular-weight hydroxyacids in marine atmospheric aerosol: evidence of a marine microbial origin

    NASA Astrophysics Data System (ADS)

    Miyazaki, Y.; Sawano, M.; Kawamura, K.

    2014-04-01

    Lactic acid (LA) and glycolic acid (GA), which are low-molecular-weight hydroxyacids, were identified in the particle and gas phases within the marine atmospheric boundary layer over the western subarctic North Pacific. Major portion of LA (81%) and GA (57%) were present in the particulate phase, which is consistent with the presence of a hydroxyl group in these molecules leading to the low volatility of the compounds. The average concentration of LA in more biologically influenced marine aerosols (average 33 ± 58 ng m-3) was substantially higher than that in less biologically influenced aerosols (average 11 ± 12 ng m-3). Over the oceacnic region of phytoplankton blooms, the concentration of aerosol LA was comparable to that of oxalic acid, which was the most abundant diacid during the study period. A positive correlation was found between the LA concentrations in more biologically influenced aerosols and chlorophyll a in seawater (r2 = 0.56), suggesting an important production of aerosol LA possibly associated with microbial (e.g., lactobacillus) activity in seawater and/or aerosols. Our finding provides a new insight into the poorly quantified microbial sources of marine organic aerosols (OA) because such low-molecular-weight hydroxyacids are key intermediates for OA formation.

  15. Low-molecular-weight hydroxyacids in marine atmospheric aerosol: evidence of a marine microbial origin

    NASA Astrophysics Data System (ADS)

    Miyazaki, Y.; Sawano, M.; Kawamura, K.

    2014-08-01

    Lactic acid (LA) and glycolic acid (GA), which are low-molecular-weight hydroxyacids, were identified in the particle and gas phases within the marine atmospheric boundary layer over the western subarctic North Pacific. A major portion of LA (81%) and GA (57%) was present in the particulate phase, which is consistent with the presence of a hydroxyl group in these molecules leading to the low volatility of the compounds. The average concentration (±SD) of LA in more biologically influenced marine aerosols (33 ± 58 ng m-3) was substantially higher than that in less biologically influenced aerosols (11 ± 12 ng m-3). Over the oceanic region of phytoplankton blooms, the concentration of aerosol LA was comparable to that of oxalic acid, which was the most abundant diacid during the study period. A positive correlation was found between the LA concentrations in more biologically influenced aerosols and chlorophyll a in seawater (r2 = 0.56), suggesting an important production of aerosol LA possibly associated with microbial (e.g., lactobacillus) activity in seawater and/or aerosols. Our finding provides a new insight into the poorly quantified microbial sources of marine organic aerosols (OAs) because such low-molecular-weight hydroxyacids are key intermediates for OA formation.

  16. Sorption and desorption kinetics and isotherms of volatile methylsiloxanes with atmospheric aerosols.

    PubMed

    Kim, Jaeshin; Xu, Shihe

    2016-02-01

    This study investigated sorption and desorption behaviors of airborne volatile methylsiloxanes (VMS) such as octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) on nine major primary and secondary atmospheric aerosols at a relative humidity (RH) of 30%. It was found that sorption and desorption of VMS took place via a two-phase process, which included an initial rapid step, followed by slower subsequent step. The initial rapid step was favored especially at low concentrations. Equilibrium sorption isotherms were slightly better fitted to Polanyi-Manes sorption model than Langmuir model except D4 on black carbon and D5 on sea salt. Values of apparent aerosol-air partition coefficients ranged 0.09-50.4 L/m(2) for D4 and 2.1-284 L/m(2) for D5 with carbon black having the largest values. Some of aerosols such as carbon black and sea salts reversibly interacted with D4 and D5 whereas other aerosols such as kaolinite and sulfates showed highly irreversible sorption for the VMS, especially at low concentrations. As sorption density of D4 and D5 on kaolinite was decreased from 1100 to 250 µg/m(2), the irreversible fraction was increased from 27% to 80%.The mechanism responsible for these differences is essential for a better understanding and prediction of atmospheric chemistry of VMS as affected by the presence of atmospheric aerosols.

  17. High aerosol acidity despite declining atmospheric sulfate concentrations over the past 15 years

    NASA Astrophysics Data System (ADS)

    Weber, Rodney J.; Guo, Hongyu; Russell, Armistead G.; Nenes, Athanasios

    2016-04-01

    Particle acidity affects aerosol concentrations, chemical composition and toxicity. Sulfate is often the main acid component of aerosols, and largely determines the acidity of fine particles under 2.5 μm in diameter, PM2.5. Over the past 15 years, atmospheric sulfate concentrations in the southeastern United States have decreased by 70%, whereas ammonia concentrations have been steady. Similar trends are occurring in many regions globally. Aerosol ammonium nitrate concentrations were assumed to increase to compensate for decreasing sulfate, which would result from increasing neutrality. Here we use observed gas and aerosol composition, humidity, and temperature data collected at a rural southeastern US site in June and July 2013 (ref. ), and a thermodynamic model that predicts pH and the gas-particle equilibrium concentrations of inorganic species from the observations to show that PM2.5 at the site is acidic. pH buffering by partitioning of ammonia between the gas and particle phases produced a relatively constant particle pH of 0-2 throughout the 15 years of decreasing atmospheric sulfate concentrations, and little change in particle ammonium nitrate concentrations. We conclude that the reductions in aerosol acidity widely anticipated from sulfur reductions, and expected acidity-related health and climate benefits, are unlikely to occur until atmospheric sulfate concentrations reach near pre-anthropogenic levels.

  18. Radical loss in the atmosphere from Cu-Fe redox coupling in aerosols

    NASA Astrophysics Data System (ADS)

    Mao, J.; Fan, S.; Jacob, D. J.; Travis, K. R.

    2013-01-01

    The hydroperoxyl radical (HO2) is a major precursor of OH and tropospheric ozone. OH is the main atmospheric oxidant, while tropospheric ozone is an important surface pollutant and greenhouse gas. Standard gas-phase models for atmospheric chemistry tend to overestimate observed HO2 concentrations, and this has been tentatively attributed to heterogeneous uptake by aerosol particles. It is generally assumed that HO2 uptake by aerosol involves conversion to H2O2, but this is of limited efficacy as an HO2 sink because H2O2 can photolyze to regenerate OH and from there HO2. Joint atmospheric observations of HO2 and H2O2 suggest that HO2 uptake by aerosols may in fact not produce H2O2. Here we propose a catalytic mechanism involving coupling of the transition metal ions Cu(I)/Cu(II) and Fe(II)/Fe(III) to rapidly convert HO2 to H2O in aqueous aerosols. The implied HO2 uptake and conversion to H2O significantly affects global model predictions of tropospheric OH, ozone, carbon monoxide (CO) and other species, improving comparisons to observations in the GEOS-Chem model. It represents a previously unrecognized positive radiative forcing of aerosols through the effects on the chemical budgets of major greenhouse gases including methane and hydrofluorocarbons (HFCs).

  19. Inverse atmospheric radiative transfer problems - A nonlinear minimization search method of solution. [aerosol pollution monitoring

    NASA Technical Reports Server (NTRS)

    Fymat, A. L.

    1976-01-01

    The paper studies the inversion of the radiative transfer equation describing the interaction of electromagnetic radiation with atmospheric aerosols. The interaction can be considered as the propagation in the aerosol medium of two light beams: the direct beam in the line-of-sight attenuated by absorption and scattering, and the diffuse beam arising from scattering into the viewing direction, which propagates more or less in random fashion. The latter beam has single scattering and multiple scattering contributions. In the former case and for single scattering, the problem is reducible to first-kind Fredholm equations, while for multiple scattering it is necessary to invert partial integrodifferential equations. A nonlinear minimization search method, applicable to the solution of both types of problems has been developed, and is applied here to the problem of monitoring aerosol pollution, namely the complex refractive index and size distribution of aerosol particles.

  20. A review of chemical and physical characterisation of atmospheric metallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Sanderson, Paul; Delgado-Saborit, Juana Maria; Harrison, Roy M.

    2014-09-01

    Knowledge of the human health impacts associated with airborne nanoparticle exposure has led to considerable research activity aimed at better characterising these particles and understanding which particle properties are most important in the context of effects on health. Knowledge of the sources, chemical composition, physical structure and ambient concentrations of nanoparticles has improved significantly as a result. Given the known toxicity of many metals and the contribution of nanoparticles to their oxidative potential, the metallic content of the nanoparticulate burden is likely to be an important factor to consider when attempting to assess the impact of nanoparticle exposure on health. This review therefore seeks to draw together the existing knowledge of metallic nanoparticles in the atmosphere and discuss future research priorities in the field. The article opens by outlining the reasons behind the current research interest in the field, and moves on to discuss sources of nanoparticles to the atmosphere. The next section reviews ambient concentrations, covering spatial and temporal variation, mass and number size distributions, air sampling and measurement techniques. Further sections discuss the chemical and physical composition of particles. The review concludes by summing up the current state of research in the area and considering where future research should be focused.

  1. Sources and source processes of organic nitrogen aerosols in the atmosphere

    NASA Astrophysics Data System (ADS)

    Erupe, Mark E.

    The research in this dissertation explored the sources and chemistry of organic nitrogen aerosols in the atmosphere. Two approaches were employed: field measurements and laboratory experiments. In order to characterize atmospheric aerosol, two ambient studies were conducted in Cache Valley in Northern Utah during strong winter inversions of 2004 and 2005. The economy of this region is heavily dependent on agriculture. There is also a fast growing urban population. Urban and agricultural emissions, aided by the valley geography and meteorology, led to high concentrations of fine particles that often exceeded the national ambient air quality standards. Aerosol composition was dominated by ammonium nitrate and organic species. Mass spectra from an aerosol mass spectrometer revealed that the organic ion peaks were consistent with reduced organic nitrogen compounds, typically associated with animal husbandry practices. Although no direct source characterization studies have been undertaken in Cache Valley with an aerosol mass spectrometer, spectra from a study at a swine facility in Ames, Iowa, did not show any evidence of reduced organic nitrogen species. This, combined with temporal and diurnal characteristics of organic aerosol peaks, was a pointer that the organic nitrogen species in Cache Valley likely formed from secondary chemistry. Application of multivariate statistical analyses to the organic aerosol spectra further supported this hypothesis. To quantify organic nitrogen signals observed in ambient studies as well as understand formation chemistry, three categories of laboratory experiments were performed. These were calibration experiments, smog chamber studies, and an analytical method development. Laboratory calibration experiments using standard calibrants indicated that quantifying the signals from organic nitrogen species was dependent on whether they formed through acid-base chemistry or via secondary organic aerosol pathway. Results from smog chamber

  2. The Impact of Biogenic and Anthropogenic Atmospheric Aerosol on Climate in Egypt

    NASA Astrophysics Data System (ADS)

    Ibrahim, A. I.; Zakey, A.; Steiner, A. L.; Shokr, M. E.; El-Raey, M.; Ahmed, Y.; Al-Hadidi, A.; Zakey, A.

    2014-12-01

    Aerosols are indicators of air quality as they reduce visibility and adversely affect public health. Aerosol optical depth (AOD) is a measure of the radiation extinction due to interaction of radiation with aerosol particles in the atmosphere. Using this optical measure of atmospheric aerosols we explore the seasonal and annual patterns of aerosols from both anthropogenic and biogenic sources over Egypt. Here, we use an integrated environment-climate-aerosol model in conjunction with inversion technique to identify the aerosol particle size distribution over different locations in Egypt. The online-integrated Environment-Climate-Aerosol model (EnvClimA), which is based on the International Center for Theoretical Physics Regional Climate Model (ICTP-RegCM), is used to study the emission of different aerosols and their impact on climate parameters for a long-term base line simulation run over Egypt and North Africa. The global emission inventory is downscaled and remapping them over Egypt using local factors such as population, traffic and industrial activities to identify the sources of anthropogenic and biogenic emission from local emission over Egypt. The results indicated that the dominant natural aerosols over Egypt are dust emissions that frequently occur during the transitional seasons (Spring and Autumn). From the local observation we identify the number of dust and sand storm occurrences over Egypt. The Multiangle Imaging SpectroRadiometer (MISR) is used to identify the optical characterizations of different types of aerosols over Egypt. Modeled aerosol optical depth and MISR observed (at 555 nm) are compared from March 2000 through November 2013. The results identify that the MISR AOD captures the maximum peaks of AOD in March/April that coincide with the Khamasin dust storms. However, peaks in May are either due to photochemical reactions or anthropogenic activities. Note: This presentation is for a Partnerships for Enhanced Engagement in Research (PEER

  3. Characterisation of Secondary Organic Aerosol Formed from the Photooxidation of Isoprene during Cloud Condensation-Evaporation Cycles (CUMULUS Project)

    NASA Astrophysics Data System (ADS)

    Doussin, J. F.; Giorio, C.; Bregonzio-Rozier, L.; Siekmann, F.; Temime-Roussel, B.; Gratien, A.; Ravier, S.; Pangui, E.; Tapparo, A.; Kalberer, M.; Vermeylen, R.; Claeys, M.; Monod, A.

    2014-12-01

    Biogenic volatile organic compounds (BVOCs) undergo many oxidation processes in the atmosphere accompanied by formation of water-soluble compounds. These compounds could partition into atmospheric water droplets, and react within the aqueous phase producing higher molecular weight and less volatile compounds which could form new aerosol (Ervens et al., 2011). This work investigates the formation and composition of secondary organic aerosol (SOA) from the photooxidation of isoprene and methacrolein (its main first-generation oxidation product) and the effect of cloud water on SOA formation and composition. The experiments were performed within the CUMULUS project (CloUd MULtiphase chemistry of organic compoUndS in the troposphere) at the 4.2 m3 stainless steel CESAM chamber (Wang et al., 2011). In each experiment, isoprene or methacrolein was injected in the chamber together with HONO under dry conditions before irradiation. The experimental protocol was optimised to generate cloud events in the chamber, lasting for ca. 10 minutes in the presence of light. Gas phase compounds were analyzed on-line by a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToF-MS), a Fourier Transform Infrared Spectrometer (FTIR), NOx and O3 analyzers. SOA formation and composition were analysed on-line with a Scanning Mobility Particle Sizer (SMPS) and an Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and off-line through sampling on filters and analysis in GC-MS and LC-MS. We observed that during cloud formation water soluble gas-phase oxidation products readily partitioned into cloud droplets and new SOA was promptly produced. Chemical composition, elemental ratios and density of SOA were compared before, during cloud formation and after cloud evaporation. Ervens, B. et al. (2011) Atmos. Chem. Phys. 11, 11069-11102. Wang, J. et al. (2011) Atmos. Measur. Tech. 4, 2465-2494.

  4. Multitechnique characterisation of 304L surface states oxidised at high temperature in steam and air atmospheres

    NASA Astrophysics Data System (ADS)

    Mamede, Anne-Sophie; Nuns, Nicolas; Cristol, Anne-Lise; Cantrel, Laurent; Souvi, Sidi; Cristol, Sylvain; Paul, Jean-François

    2016-04-01

    In case of a severe accident occurring in a nuclear reactor, surfaces of the reactor coolant system (RCS), made of stainless steel (304L) rich in Cr (>10%) and Ni (8-12%), are oxidised. Fission products (FPs) are released from melt fuel and flow through the RCS. A part of them is deposited onto surfaces either by vapour condensation or by aerosol deposition mechanisms. To be able to understand the nature of interactions between these FPs and the RCS surfaces, a preliminary step is to characterize the RSC surface states in steam and air atmosphere at high temperatures. Pieces of 304L stainless steel have been treated in a flow reactor at two different temperatures (750 °C and 950 °C) for two different exposition times (24 h and 72 h). After surfaces analysing by a unique combination of surface analysis techniques (XPS, ToF-SIMS and LEIS), for 304L, the results show a deep oxide scale with multi layers and the outer layer is composed of chromium and manganese oxides. Oxide profiles differ in air or steam atmosphere. Fe2O3 oxide is observed but in minor proportion and in all cases no nickel is detected near the surface. Results obtained are discussed and compared with the literature data.

  5. Single scattering solution for radiative transfer through Rayleigh and aerosol atmosphere

    NASA Technical Reports Server (NTRS)

    Otterman, J.

    1977-01-01

    A solution is presented to the radiative transfer of the solar irradiation through a turbid atmosphere, based on the single-scattering approximation, i.e., an assumption that a photon that underwent scattering either leaves the top of the atmosphere or strikes the surface. The solution depends on a special idealization of the scattering phase function of the aerosols. The equations developed are subsequently applied to analyze quantitatively the enhancement of the surface irradiation and the enhancement of the scattered radiant emittance as seen from above the atmosphere, caused by the surface reflectance and atmospheric back scattering. An order of magnitude error analysis is presented.

  6. Chemical characterisation of semi-volatile and aerosol compounds from the photooxidation of toluene and NOx

    NASA Astrophysics Data System (ADS)

    White, Stephen J.; Jamie, Ian M.; Angove, Dennys E.

    2014-02-01

    The chemical composition of a gas phase and secondary organic aerosol (SOA) mixture from toluene photooxidation in NOx was determined. Aerosol from toluene photooxidation was generated in a smog chamber and was collected onto glass fibre filters along with those gas phase compounds which adhered to the filter. The filter bound organic material was extracted, derivatised with O-2,3,4,5,6-pentafluorobenzyl hydroxylamine (PFBHA) and N,O-bistrimethylsilyl-trifluoroacetamide (BSTFA), then analysed using gas chromatography-mass spectrometry (GC-MS). Compound identification was aided by the use of isotopically-labelled toluene. The effect of humidity on product formation was investigated by raising water vapour concentration in one experiment. Sixty compounds were identified, of which twenty had not been identified from toluene photooxidation previously. Small carboxylic acids and dicarbonyls provided the highest proportion of identifiable compounds by relative response. The use of water to extract the filter samples resulted in much higher relative responses for oxocarboxylic acids, such as glyoxylic acid and pyruvic acid, than has been observed in previous studies. The formation of levulinic acid was determined to be due to the reaction of water with aromatic photooxidation products in the gas phase or particle phase of the chamber experiment. Nuclear magnetic resonance (NMR) was used to determine the functional groups of water-extracted organic material, which indicated that the water-soluble components were comprised of compounds which contain similar functional groups, primarily alcohols and carboxylic acids.

  7. Quantification and radiocarbon source apportionment of black carbon in atmospheric aerosols using the CTO-375 method

    NASA Astrophysics Data System (ADS)

    Zencak, Zdenek; Elmquist, Marie; Gustafsson, Örjan

    To make progress towards linking the atmosphere and biogeosphere parts of the black carbon (BC) cycle, a chemothermal oxidation method (CTO-375), commonly applied for isolating BC from complex geomatrices such as soils, sediments and aquatic particles, was applied to investigate the BC also in atmospheric particles. Concentrations and 14C-based source apportionment of CTO-375 based BC was established for a reference aerosol (NIST RM-8785) and for wintertime aerosols collected in Stockholm and in a Swedish background area. The results were compared with thermal-optical (OC/EC) measurements. For NIST RM-8785, a good agreement was found between the BC CTO-375 concentration and the reported elemental carbon (EC) concentration measured by the "Speciation Trends Network—National Institute of Occupational Safety and Health" method (EC NIOSH) with BC CTO-375 of 0.054±0.002 g g -1 and EC NIOSH of 0.067±0.008 g g -1. In contrast, there was an average factor of ca. 20 difference between BC CTO-375 and EC NIOSH for the ambient Scandinavian wintertime aerosols, presumably reflecting a combination of BC CTO-375 isolating only the recalcitrant soot-BC portion of the BC continuum and the EC NIOSH metric inadvertently including some intrinsically non-pyrogenic organic matter. Isolation of BC CTO-375 with subsequent off-line radiocarbon analysis yielded fraction modern values (fM) for total organic carbon (TOC) of 0.93 (aerosols from a Swedish background area), and 0.58 (aerosols collected in Stockholm); whereas the fM for BC CTO-375 isolates were 1.08 (aerosols from a Swedish background area), and 0.87 (aerosols collected in Stockholm). This radiocarbon-based source apportionment suggests that contribution from biomass combustion to cold-season atmospheric BC CTO-375 in Stockholm was 70% and in the background area 88%.

  8. Is there an abnormal enhancement of atmospheric aerosol before the 2008 Wenchuan earthquake?

    NASA Astrophysics Data System (ADS)

    Qin, K.; Wu, L. X.; Zheng, S.; Bai, Y.; Lv, X.

    2014-09-01

    There are extensive reports of ionospheric disturbances before the great 2008 Wenchuan earthquake, which are possibly explained by seismogenic electric field hypotheses linked with the aerosols injected in atmosphere. This paper attempts to investigate the possible change of atmospheric aerosol optical depth (AOD) associated with this earthquake by using MODIS data from both Terra and Aqua satellites. The result shows a clear enhancement of AOD along the Longmenshan faults 7 days before the quake, which is 1 day and 4 days earlier than the reported negative and positive ionospheric disturbances, respectively, and is 1 day earlier than or quasi-synchronism with other reported atmospheric anomalies including air temperature, outgoing longwave radiation and relative humidity. Particularly, the spatial distribution of AOD enhancement is very local and it is correlated well with the active faults and surface ruptures. We suggest that this unique enhancement could be associated with the Lithosphere-Atmosphere-Ionosphere coupling process during the preparation of the Wenchuan earthquake.

  9. Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol

    SciTech Connect

    Massachusetts Institute of Technology; Kroll, Jesse H.; Donahue, Neil M.; Jimenez, Jose L.; Kessler, Sean H.; Canagaratna, Manjula R.; Wilson, Kevin R.; Altieri, Katye E.; Mazzoleni, Lynn R.; Wozniak, Andrew S.; Bluhm, Hendrik; Mysak, Erin R.; Smith, Jared D.; Kolb, Charles E.; Worsnop, Douglas R.

    2010-11-05

    A detailed understanding of the sources, transformations, and fates of organic species in the environment is crucial because of the central roles that organics play in human health, biogeochemical cycles, and Earth's climate. However, such an understanding is hindered by the immense chemical complexity of environmental mixtures of organics; for example, atmospheric organic aerosol consists of at least thousands of individual compounds, all of which likely evolve chemically over their atmospheric lifetimes. Here we demonstrate the utility of describing organic aerosol (and other complex organic mixtures) in terms of average carbon oxidation state (OSC), a quantity that always increases with oxidation, and is readily measured using state-of-the-art analytical techniques. Field and laboratory measurements of OSC , using several such techniques, constrain the chemical properties of the organics and demonstrate that the formation and evolution of organic aerosol involves simultaneous changes to both carbon oxidation state and carbon number (nC).

  10. Gas-aerosol partitioning of semi volatile carbonyls in polluted atmosphere in Hachioji, Tokyo

    NASA Astrophysics Data System (ADS)

    Matsunaga, Sou N.; Kato, Shungo; Yoshino, Ayako; Greenberg, Jim P.; Kajii, Yoshizumi; Guenther, Alex B.

    2005-06-01

    Gaseous and particulate semi volatile carbonyls have been measured in urban air using an annular denuder sampling system. Three dicarbonyls, five aliphatic aldehydes and two hydroxy carbonyls were observed. Concentrations of other biogenic and anthropogenic volatile organic compounds (VOCs), SO2, CO, NO2 and particle concentration were also measured. Estimated gas-aerosol equilibrium constants for the carbonyls showed an inverse correlation with the concentrations of anthropogenic pollutants such as benzene, isopentane and SO2. This suggests that the increase in the fraction of non-polar anthropogenic particles in the atmosphere could change the average property of the ambient aerosols and drive the gas particle equilibrium of the carbonyls to the gas phase. This trend is uncommon in remote forest air. In this study, we examined the factors controlling the equilibrium in the polluted atmosphere and show that there is a difference in gas-aerosol partition between polluted and clean air.

  11. Organic Aerosol Volatility Parameterizations and Their Impact on Atmospheric Composition and Climate

    NASA Technical Reports Server (NTRS)

    Tsigaridis, Kostas; Bauer, Susanne E.

    2015-01-01

    Despite their importance and ubiquity in the atmosphere, organic aerosols are still very poorly parameterized in global models. This can be explained by two reasons: first, a very large number of unconstrained parameters are involved in accurate parameterizations, and second, a detailed description of semi-volatile organics is computationally very expensive. Even organic aerosol properties that are known to play a major role in the atmosphere, namely volatility and aging, are poorly resolved in global models, if at all. Studies with different models and different parameterizations have not been conclusive on whether the additional complexity improves model simulations, but the added diversity of the different host models used adds an unnecessary degree of variability in the evaluation of results that obscures solid conclusions. Aerosol microphysics do not significantly alter the mean OA vertical profile or comparison with surface measurements. This might not be the case for semi-volatile OA with microphysics.

  12. Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol.

    PubMed

    Kroll, Jesse H; Donahue, Neil M; Jimenez, Jose L; Kessler, Sean H; Canagaratna, Manjula R; Wilson, Kevin R; Altieri, Katye E; Mazzoleni, Lynn R; Wozniak, Andrew S; Bluhm, Hendrik; Mysak, Erin R; Smith, Jared D; Kolb, Charles E; Worsnop, Douglas R

    2011-02-01

    A detailed understanding of the sources, transformations and fates of organic species in the environment is crucial because of the central roles that they play in human health, biogeochemical cycles and the Earth's climate. However, such an understanding is hindered by the immense chemical complexity of environmental mixtures of organics; for example, atmospheric organic aerosol consists of at least thousands of individual compounds, all of which likely evolve chemically over their atmospheric lifetimes. Here, we demonstrate the utility of describing organic aerosol (and other complex organic mixtures) in terms of average carbon oxidation state, a quantity that always increases with oxidation, and is readily measured using state-of-the-art analytical techniques. Field and laboratory measurements of the average carbon oxidation state, using several such techniques, constrain the chemical properties of the organics and demonstrate that the formation and evolution of organic aerosol involves simultaneous changes to both carbon oxidation state and carbon number.

  13. Characteristics and Composition of Atmospheric Aerosols in Phimai, Central Thailand During BASE-ASIA

    NASA Technical Reports Server (NTRS)

    Li, Can; Tsay, Si-Chee; Hsu, N. Christina; Kim, Jin Young; Howell, Steven G.; Huebert, Barry J.; Ji, Qiang; Jeong, Myeong-Jae; Wang, Sheng-Hsiang; Hansell, Richard A.; Bell, Shaun W.

    2012-01-01

    Popular summary: Atmospheric aerosols play an important role in the Earth's climate system, and can also have adverse effects on air quality and human health. The environmental impacts of aerosols, on the other hand, are highly regional, since their temporal/spatial distribution is inhomogeneous and highly depends on the regional emission sources. To better understand the effects of aerosols, intensive field experiments are necessary to characterize the chemical and physical properties on a region-by-region basis. From late February to early May in 2006, NASA/GSFC's SMARTLabs facility was deployed at a rural site in central Thailand, Southeast Asia, to conduct a field experiment dubbed BASE-ASIA (Biomass-burning Aerosols in South East-Asia: Smoke Impact Assessment). The group was joined by scientists from the University of Hawaii and other regional institutes. Comprehensive measurements were made during the experiment, including aerosol chemical composition, optical and microphysical properties, as well as surface energetics and local . meteorology. This study analyzes part of the data from the BASE-ASIA experiment. It was found that, even for the relatively remote rural site, the aerosol loading was still substantial. Besides agricultural burning in the area, industrial pollution near the Bangkok metropolitan area, about 200 km southeast of the site, and even long-range transport from China, also contribute to the area's aerosol loading. The results indicate that aerosol pollution has developed into a regional problem for northern Indochina, and may become more severe as the region's population and economy continue to grow. Abstract: Comprehensive measurements of atmospheric aerosols were made in Phimai, central Thailand (15.l83 N, 102.565 E, elevation: 206 m) during the BASE-ASIA field experiment from late February to early May in 2006. The observed aerosol loading was sizable for this rural site (mean aerosol scattering: 108 +/- 64 Mm(exp -1); absorption: 15

  14. Impact of Nonabsorbing Anthropogenic Aerosols on Clear-Sky Atmospheric Absorption

    NASA Technical Reports Server (NTRS)

    Stier, Philip; Seinfeld, John H.; Kinne, Stefan; Feichter,Johann; Boucher, Olivier

    2006-01-01

    Absorption of solar radiation by atmospheric aerosol has become recognized as important in regional and global climate. Nonabsorbing, hydrophilic aerosols, such as sulfate, potentially affect atmospheric absorption in opposing ways: first, decreasing absorption through aging initially hydrophobic black carbon (BC) to a hydrophilic state, enhancing its removal by wet scavenging, and consequently decreasing BC lifetime and abundance, and second, increasing absorption through enhancement of the BC absorption efficiency by internal mixing as well as through increasing the amount of diffuse solar radiation in the atmosphere. On the basis of General Circulation Model studies with an embedded microphysical aerosol module we systematically demonstrate the significance of these mechanisms both on the global and regional scales. In remote transport regions, the first mechanism prevails, reducing atmospheric absorption, whereas in the vicinity of source regions, despite enhanced wet scavenging, absorption is enhanced owing to the prevalence of the second mechanisms. Our findings imply that the sulfur to BC emission ratio plays a key role in aerosol absorption.

  15. Understanding the Nature of Marine Aerosols and Their Effects in the Coupled Ocean-Atmosphere System

    DTIC Science & Technology

    2012-09-30

    instruments (DASH-SP and CVI). Dr. Graham Feingold (National Oceanic and Atmospheric Administration) collaborated with the PI on using cloud models...E-PEACE). An on-going collaboration with Dr. Daniel Partridge (University of Oxford) has involved conducting inverse modelling of aerosol-cloud

  16. Some results of CO and aerosols atmospheric pollution investigations in Moscow and Beijing

    NASA Astrophysics Data System (ADS)

    Rakitin, Vadim; Wang, Gengchen; Wang, Pusai; Grechko, Evgeny; Dzhola, Anatoly; Emilenko, Alexander; Fokeeva, Ekaterina; Kopeikin, Vladimir; Safronov, Alexander

    2014-05-01

    Results of the CO total column (TC) and submicron (sbm) and soot concentrations measurements in Moscow and Beijing for period from 1992 to 2013 years are presented. The rate of decrease of CO TC Moscow anthropogenic portion is 1.4 % per year for 1992-2013 years in spite of multiple increase of the motor vehicles number. There are no significant changes in CO TC over Beijing for whole period of measurements (1992-2013 years). Soot concentration in Beijing has decreased while sbm aerosol has increased since 2006 year. Level of atmospheric CO and aerosols pollution in Beijing is 2-5 times stronger in comparison with Moscow ones. Reasonably typical of atmospheric pollution events for Beijing with extreme values of CO TC and aerosols concentrations were observed in Moscow during wild fires of 2002 and 2010 years only. Trajectory cluster analysis using has allowed studying the location of sources of CO and aerosols emissions. Relatively stronger atmospheric pollution of Beijing partially due to the atmospheric transportation from industry regions of China located to south, south-east and east from the city.

  17. Influence of a high aerosol concentration on the thermal structure of the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Khaikin, M. N.; Kuznetsova, I. N.; Kadygrov, E. N.

    2006-12-01

    The influence of increased concentrations of submicron aerosol produced by forest fires on thermal characteristics of the atmospheric boundary layer (ABL) in Moscow and its remote vicinity (the town of Zvenigorod) are analyzed on the basis of regular remote measurements of the ABL temperature profile with the use of MTP-5 profilers. In the air basin of a large city, additional aerosol and accompanying pollutants in early morning hours (at small heights of the Sun) most frequently did not cause substantial changes in the ABL thermal structure. In the locality remote from the megalopolis (Zvenigorod), the atmospheric pollution by aerosol led to noticeable changes in the ABL thermal characteristics. Especially strong changes were observed in the daytime, during the maximum supply of solar radiation. In morning hours, the heating rate of the lower 100-m layer of the polluted air exceeded the heating rate of a relatively pure air by more than one degree. In higher layers, the differences between the rates of temperature changes in a relatively clean atmosphere and in an atmosphere polluted by aerosol (in the suburb) were insignificant.

  18. SEMI-VOLATILE SECONDARY AEROSOLS IN URBAN ATMOSPHERES: MEETING A MEASURED CHALLENGE

    EPA Science Inventory

    This presentation compares the results from various particle measurement methods as they relate to semi-volatile secondary aerosols in urban atmospheres. The methods include the PM2.5 Federal Reference Method; Particle Concentrator - BYU Organic Sampling System (PC-BOSS); the Re...

  19. Atmospheric aerosols: A literature summary of their physical characteristics and chemical composition

    NASA Technical Reports Server (NTRS)

    Harris, F. S., Jr.

    1976-01-01

    This report contains a summary of 199 recent references on the characterization of atmospheric aerosols with respect to their composition, sources, size distribution, and time changes, and with particular reference to the chemical elements measured by modern techniques, especially activation analysis.

  20. The importance of aerosol composition and mixing state on predicted CCN concentration and the variation of the importance with atmospheric processing of aerosol

    SciTech Connect

    Wang, J.; Cubison, M.; Aiken, A.; Jimenez, J.; Collins, D.; Gaffney, J.; Marley, N.

    2010-03-15

    The influences of atmospheric aerosols on cloud properties (i.e., aerosol indirect effects) strongly depend on the aerosol CCN concentrations, which can be effectively predicted from detailed aerosol size distribution, mixing state, and chemical composition using Köhler theory. However, atmospheric aerosols are complex and heterogeneous mixtures of a large number of species that cannot be individually simulated in global or regional models due to computational constraints. Furthermore, the thermodynamic properties or even the molecular identities of many organic species present in ambient aerosols are often not known to predict their cloud-activation behavior using Köhler theory. As a result, simplified presentations of aerosol composition and mixing state are necessary for large-scale models. In this study, aerosol microphysics, CCN concentrations, and chemical composition measured at the T0 urban super-site in Mexico City during MILAGRO are analyzed. During the campaign in March 2006, aerosol size distribution and composition often showed strong diurnal variation as a result of both primary emissions and aging of aerosols through coagulation and local photochemical production of secondary aerosol species. The submicron aerosol composition was ~1/2 organic species. Closure analysis is first carried out by comparing CCN concentrations calculated from the measured aerosol size distribution, mixing state, and chemical composition using extended Köhler theory to concurrent CCN measurements at five supersaturations ranging from 0.11% to 0.35%. The closure agreement and its diurnal variation are studied. CCN concentrations are also derived using various simplifications of the measured aerosol mixing state and chemical composition. The biases associated with these simplifications are compared for different supersaturations, and the variation of the biases is examined as a function of aerosol age. The results show that the simplification of internally mixed, size

  1. Atmospheric Observations of Aerosol Sizes, Sulfuric Acid and Ammonia Measured in Kent, Ohio

    NASA Astrophysics Data System (ADS)

    Pavuluri, C.; Benson, D. R.; Dailey, B.; Lee, S.

    2008-12-01

    Atmospheric particles affect atmospheric composition, cloud formation, global radiation budget, and human health. Nucleation is a gas-to-particle conversion process in which new particles form directly from gas phase species and is a key process that controls particle number concentrations. The most common feature of the new particle formation events is a substantial increase of number concentrations of nucleation mode particles reaching up to 105-106 cm-3 in the condensable vapor-laden air. There are several nucleation mechanisms for tropopsheric aerosol formation, but it is unclear which nucleation process dominates. In particular, observations and modeling studies show that ammonia can be important for atmospheric nucleation in the boundary layer, but simultaneous measurements of aerosol sizes and precursors including sulfuric acid and ammonia are critically lacking. In order to overcome these shortcomings, we conduct atmospheric observations of new particle formation in Kent, OH. We have measured aerosol sizes and concentrations for particles in the size range from 3-102 nm semi- continuously from December 2005 and for particles from 3-1000 nm continuously from September 2007 in Kent State campus, Kent, OH (with an inlet placed at ~11.5 m above ground level). We also simultaneously measure sulfuric acid and ammonia, two most important inorganic aerosol precursors, with two chemical ionization mass spectrometers (CIMS) from August 2008. Kent, located in Northeastern Ohio, is relatively rural itself, but is also surrounded by several urban cities within 40 miles. Because of the combination of its relatively rural environment (hence low surface areas of aerosol particles), active vegetation (organic and NH3 emissions), and possible transport of aerosol precursors from the surrounding urban and industrialized areas, Kent is a unique location to make new particle formation studies. So far, most of new particle formation observations made typically in US were at

  2. Formation and Processing of Secondary Organic Aerosol from Catechol as a Model for Atmospheric HULIS

    NASA Astrophysics Data System (ADS)

    Ofner, Johannes; Krüger, Heinz-Ulrich; Grothe, Hinrich; Zetzsch, Cornelius

    2010-05-01

    A particular fraction of the secondary organic aerosol (SOA) termed HUmic Like Substances (HULIS) attracted attention only recently in atmospheric aerosol, initiating a discourse about their aromaticity and other properties, such as reactivity and hygroscopicity. A major portion of HULIS originates from volatile organic compounds, which are formed by abiotic oxidation reactions involving mainly OH radicals, ozone, nitrogen oxides and possibly halogens. Subsequently, the particles provide surface for heterogeneous reactions with atmospheric trace gases. Thus, aerosol smog-chamber studies with appropriate precursors are needed to generate SOA with HULIS qualities in situ inside the smog chamber and study their possible interactions. Catechol and guaiacol were chosen as aromatic precursors for synthetic HULIS production. The SOA was produced in a 700 L aerosol smog chamber, equipped with a solar simulator. SOA formation from each precursor was investigated at simulated environmental conditions (humidity, light, and presence of oxidizers) and characterized with respect to HULIS properties by particle classifiers, Fourier Transform IR spectroscopy (by long-path absorption and attenuated total reflection), UV/VIS spectroscopy, high-resolution mass-spectroscopy and temperature-programmed-desorption mass-spectrometry. High-resolution imaging was obtained using Field Emission Gun Scanning Electron Microscopy (FEGSEM). After HULIS formation the aerosol particles were exposed to atmospheric halogen species to study their processing with those trace gases, released by sea salt-activation. Those investigations show that aromatic precursors like catechol and guaiacol are suitable to form synthetic HULIS for laboratory-scale measurements with physical and chemical properties described in literature. However, sunlight and relative humidity play a major role in particle production and composition of functional groups, which are the anchor points for heterogeneous atmospheric

  3. Aerosol specification in single-column Community Atmosphere Model version 5

    DOE PAGES

    Lebassi-Habtezion, B.; Caldwell, P. M.

    2015-03-27

    Single-column model (SCM) capability is an important tool for general circulation model development. In this study, the SCM mode of version 5 of the Community Atmosphere Model (CAM5) is shown to handle aerosol initialization and advection improperly, resulting in aerosol, cloud-droplet, and ice crystal concentrations which are typically much lower than observed or simulated by CAM5 in global mode. This deficiency has a major impact on stratiform cloud simulations but has little impact on convective case studies because aerosol is currently not used by CAM5 convective schemes and convective cases are typically longer in duration (so initialization is less important).more » By imposing fixed aerosol or cloud-droplet and crystal number concentrations, the aerosol issues described above can be avoided. Sensitivity studies using these idealizations suggest that the Meyers et al. (1992) ice nucleation scheme prevents mixed-phase cloud from existing by producing too many ice crystals. Microphysics is shown to strongly deplete cloud water in stratiform cases, indicating problems with sequential splitting in CAM5 and the need for careful interpretation of output from sequentially split climate models. Droplet concentration in the general circulation model (GCM) version of CAM5 is also shown to be far too low (~ 25 cm−3) at the southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) site.« less

  4. Influence of atmospheric relative humidity on ultraviolet flux and aerosol direct radiative forcing: Observation and simulation

    NASA Astrophysics Data System (ADS)

    Xia, Dong; Chen, Ling; Chen, Huizhong; Luo, Xuyu; Deng, Tao

    2016-08-01

    The atmospheric aerosols can absorb moisture from the environment due to their hydrophilicity and thus affect atmospheric radiation fluxes. In this article, the ultraviolet radiation and relative humidity (RH) data from ground observations and a radiative transfer model were used to examine the influence of RH on ultraviolet radiation flux and aerosol direct radiative forcing under the clear-sky conditions. The results show that RH has a significant influence on ultraviolet radiation because of aerosol hygroscopicity. The relationship between attenuation rate and RH can be fitted logarithmically and all of the R2 of the 4 sets of samples are high, i.e. 0.87, 0.96, 0.9, and 0.9, respectively. When the RH is 60%, 70%, 80% and 90%, the mean aerosol direct radiative forcing in ultraviolet is -4.22W m-2, -4.5W m-2, -4.82W m-2 and -5.4W m-2, respectively. For the selected polluted air samples the growth factor for computing aerosol direct radiative forcing in the ultraviolet for the RH of 80% varies from 1.19 to 1.53, with an average of 1.31.

  5. [Effects of Relative Humidity and Aerosol Physicochemical Properties on Atmospheric Visibility in Northern Suburb of Nanjing].

    PubMed

    Yu, Xing-na; Ma, Jia; Zhu, Bin; Wang, Hong-lei; Yan, Shu-qi; Xia, Hang

    2015-06-01

    To understand the effects of relative humidity (RH) and aerosol physicochemical properties on the atmospheric visibility in autumn and winter in northern suburb of Nanjing, the relationships between meteorological elements, particulate matter and visibility were analyzed with the data of meteorological elements, aerosol particle spectra, particulate matter concentration and chemical composition. The average visibility was 4.76 km in autumn and winter in northern suburb of Nanjing. There was a certain negative correlation between the particulate matter concentration and the visibility, especially the influence of fine particles on the visibility was more remarkable. The occurrence frequencies of low visibilities showed an increasing trend with the increasing concentration of fine particles and RH. When the visibility decreased from 5-10 km to <5 km, the mass concentrations of PM10 and PM2.5 increased by 7.56% and 37.64%, respectively. Meanwhile, the mass concentrations of SO4(2-) and NO3-increased significantly. Effects of aerosol particle number concentration on the visibility were related with RH. Aerosol number concentration with diameters ranging from 0.5 microm to 2 microm increased slowly with the increase of RH, while those ranging from 2 microm to 10 microm decreased. The correlation analysis between the aerosol surface area concentration and the visibility showed that RH and fine particles between 0.5 microm and 2 microm were the main factors which caused the decrease of atmospheric visibility in autumn and winter in northern suburb of Nanjing.

  6. Investigation of aerosol radiative forcing and atmosphere-ocean remote sensing in Northern Norway

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Chun; Hamre, Børge; Stamnes, Snorre; Frette, Øyvind; Stamnes, Kunt; Stamnes, Jakob J.

    2013-04-01

    We examine aerosol optical properties and radiative forcing at Andenes, Northern Norway (69N, 16E, 379 m altitude) during a two-year period (2008-2010) using AERONET data, radiative transfer modelling (C-DISORT), and Mie-scattering computations. We show that the mean value of the aerosol optical thickness at 500 nm derived from AERONET measurements is close to that obtained from Mie-scattering computations with input of aerosol size distribution and refractive index as derived from AERONET measurements. Also, different models for the ground reflectance used as input to the radiative transfer computations are shown to have little impact on the aerosol radiative forcing both at the top and bottom of the atmosphere. The coupled atmosphere-surface system accounted for by C-DISORT is suitable for radiative transfer calculations over open ocean and coastal water areas, and we discuss how it can be used to make simultaneous retrieval of aerosol and marine parameters from ocean colour data.

  7. MULTI-TECHNIQUE APPROACH TO MEASURE SIZE AND TIME RESOLVED ATMOSPHERIC AND RADIONUCLIDE AEROSOLS

    SciTech Connect

    Shutthanandan, V; Xie, YuLong; Disselkamp, Robert S; Laulainen, Nels S; Smith, Edward A; Thevuthasan, Suntharampillai

    2008-12-01

    Accurate quantifications of aerosol components are crucial to predict global atmospheric transport models. Recently developed International Monitoring System (IMS) network represents an opportunity to enhance comprehensive systematic aerosol observations on a global scale because it provides a global infrastructure. As such, a local pilot study utilizing several state-of-the-art instruments has been conducted at the peak of Rattlesnake Mountain, Washington, USA, during three month periods (June-August) in 2003 to explore this opportunity. In this study, routine aerosol samples were collected using a 3-stage Cascade Impactor Beam Analyzer (0.07 to 2.5 µm) with time resolution about 6 hours on long Teflon strips while radionuclide aerosols were collected using Radionuclide aerosol sampler/analyzer (RASA) developed at Pacific Northwest National Laboratory. The elemental composition and hydrogen concentration were measured using proton induced x-ray emission (PIXE) and proton elastic scattering analysis (PESA), respectively. In addition, short and long-lived radionuclides that exist in nature were measured with same time resolution (6 hours) using RASA. In this method, high-resolution gamma-ray spectra were analyzed for radionuclide concentration. Combination of trace radioactive and non-radioactive element analysis in aerosols makes this investigation unique.

  8. Atmospheric aerosols in Amazonia and land use change: from natural biogenic to biomass burning conditions.

    PubMed

    Artaxo, Paulo; Rizzo, Luciana V; Brito, Joel F; Barbosa, Henrique M J; Arana, Andrea; Sena, Elisa T; Cirino, Glauber G; Bastos, Wanderlei; Martin, Scot T; Andreae, Meinrat O

    2013-01-01

    In the wet season, a large portion of the Amazon region constitutes one of the most pristine continental areas, with very low concentrations of atmospheric trace gases and aerosol particles. However, land use change modifies the biosphere-atmosphere interactions in such a way that key processes that maintain the functioning of Amazonia are substantially altered. This study presents a comparison between aerosol properties observed at a preserved forest site in Central Amazonia (TT34 North of Manaus) and at a heavily biomass burning impacted site in south-western Amazonia (PVH, close to Porto Velho). Amazonian aerosols were characterized in detail, including aerosol size distributions, aerosol light absorption and scattering, optical depth and aerosol inorganic and organic composition, among other properties. The central Amazonia site (TT34) showed low aerosol concentrations (PM2.5 of 1.3 +/- 0.7 microg m(-3) and 3.4 +/- 2.0 microg m(-3) in the wet and dry seasons, respectively), with a median particle number concentration of 220 cm(-3) in the wet season and 2200 cm(-3) in the dry season. At the impacted site (PVH), aerosol loadings were one order of magnitude higher (PM2.5 of 10.2 +/- 9.0 microg m(-3) and 33.0 +/- 36.0 microg m(-3) in the wet and dry seasons, respectively). The aerosol number concentration at the impacted site ranged from 680 cm(-3) in the wet season up to 20 000 cm(-3) in the dry season. An aerosol chemical speciation monitor (ACSM) was deployed in 2013 at both sites, and it shows that organic aerosol account to 81% to the non-refractory PM1 aerosol loading at TT34, while biomass burning aerosols at PVH shows a 93% content of organic particles. Three years of filter-based elemental composition measurements shows that sulphate at the impacted site decreases, on average, from 12% of PM2.5 mass during the wet season to 5% in the dry season. This result corroborates the ACSM finding that the biomass burning contributed overwhelmingly to the organic

  9. Chemical Analysis of Fractionated Halogens in Atmospheric Aerosols Collected in Okinawa, Japan

    NASA Astrophysics Data System (ADS)

    Tsuhako, A.; Miyagi, Y.; Somada, Y.; Azechi, S.; Handa, D.; Oshiro, Y.; Murayama, H.; Arakaki, T.

    2013-12-01

    Halogens (Cl, Br and I) play important roles in the atmosphere, e.g. ozone depletion by Br during spring in Polar Regions. Sources of halogens in atmospheric aerosols are mainly from ocean. But, for example, when we analyzed Br- with ion chromatography, its concentrations were almost always below the detection limit, which is also much lower than the estimated concentrations from sodium ion concentrations. We hypothesized that portions of halogens are escaped to the atmosphere, similar to chlorine loss, changed their chemical forms to such as BrO3- and IO3-, and/or even formed precipitates. There was few reported data so far about fractionated halogen concentrations in atmospheric aerosols. Thus, purpose of this study was to determine halogen concentrations in different fractions; free ion, water-soluble chemically transformed ions and precipitates using the authentic aerosols. Moreover, we analyzed seasonal variation for each fraction. Atmospheric aerosol samples were collected at Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS) of Okinawa, Japan during January 2010 and August 2013. A high volume air sampler was used for collecting total particulate matters on quartz filters on a weekly basis. Ultrapure water was used to extract water-soluble factions of halogens. The extracted solutions were filtered with the membrane filter and used for chemical analysis with ion chromatography and ICP-MS. Moreover, the total halogens in aerosols were obtained after digesting aerosols with tetramethylammonium hydroxide (TMAH) using the microwave and analysis with ICP-MS. For Cl, water-soluble Cl- accounted for about 70% of the estimates with Na content. No other forms of water-soluble Cl were found. About 30% of Cl was assumed volatilized to the gas-phase. For Br, water-soluble Br accounted for about 43% of the estimates with Na content, and within the 43%, about 10% of Br was not in the form of Br-. About 46% of Br was assumed volatilized to the gas-phase. For I

  10. Characterization of nitrocatechols and related tracers in atmospheric biomass burning organic aerosol

    NASA Astrophysics Data System (ADS)

    Grgic, I.; Kitanovski, Z.; Yasmeen, F.; Claeys, M.

    2011-12-01

    One of the largest primary sources of organic aerosols in the atmosphere is biomass burning (Laskin et al., 2009). The chemistry of compounds present in biomass burning aerosol (BBA) is diverse and directly dependent on the chemical composition of the burning material and the combustion conditions (Simoneit et al., 2002). A well-established tracer for primary BBA is levoglucosan (1,6-anhydro-β-anhydroglucose), which originates from the pyrolysis of cellulose or hemicellulose (Fine et al., 2002). Secondary BBA, which is formed after physical and chemical changes (aging) of the primary BBA in the atmosphere, contains more oxidized and polar compounds. An important class of compounds of secondary organic aerosols (SOA) is nitrocatechols, which are strong absorbers of UV and Vis light, and therefore, can affect the earth's radiative balance and climate. Recently, methyl nitrocatechols were proposed as suitable tracers for highly oxidized secondary BBA (Iinuma et al., 2010). These compounds are primarily formed from the photooxidation of m-cresol, that is emitted from biomass burning, in the presence of NOx. The objective of the present study was to characterize nitrocatechols in ambient aerosols using mass spectrometric and chromatographic techniques. Ambient aerosol samples were collected during a cold winter episode from an urban site in Maribor, Slovenia, where substantial residential wood burning for domestic purposes takes place. Emphasis was put on the development of a suitable LC-ESI-MS technique. In an initial step the chromatographic conditions were optimized for methyl nitrocatechols and related nitro-aromatic compounds using diode array UV/Vis detection. The optimized LC conditions were used for the development and validation of an LC-ESI-MS/MS method for identification and quantification of nitrocatechols in aerosol samples. LC/ESI-MS/MS data will be presented and interpreted for the nitro-aromatic compounds that are present in the collected ambient

  11. Vertical Profiling of Atmospheric Backscatter with a Raman-Aerosol Lidar

    NASA Astrophysics Data System (ADS)

    Deleva, Atanaska D.; Peshev, Zahary Y.; Slesar, Alexander S.; Denisov, Sergey; Avramov, Lachezar A.; Stoyanov, Dimitar V.

    2010-01-01

    Aerosols have a strong impact on the planet's thermal balance, air quality, and a variety of atmospheric processes and phenomena. In this work we present some results from a long term lidar observation of tropospheric aerosols over the city of Sofia, Bulgaria, within the framework of the European project "EARLINET-ASSOS." Vertical profiles of the aerosol backscattering coefficient and range corrected lidar signals are processed and analyzed. The temporal evolution and the spatial distribution of atmospheric aerosol fields are illustrated by 2D-colormaps in height-time coordinates. We present here several cases of aerosol loading: transport of Saharan dust (at altitudes from 3 km to 5 km), highly situated layers (from 9 km to 15 km), and anthropogenic smog (up to 2 km). All measurements were performed by using the two aerosol spectral channels of a combined Raman-aerosol lidar developed in the Laser Radar Lab, Institute of Electronics, Bulgarian Academy of Sciences. It is based on a Q-switched powerful frequency-doubled Nd:YAG laser (output pulse power: up to 1 J at 1064 nm; up to 100 mJ at 532 nm; pulse duration 15 ns FWHM; repetition rate 2 Hz). A Cassegrain telescope (35 cm diameter, 200 cm focal length) collects the backscattered radiation. The lidar receiving system is based on novel smart high sensitive photo-receiving modules. The acquisition system provides signal registration with spatial resolution of 15 m (100 MHz 14-bit ADC). It allows for detection, storage, and processing of large volume lidar data. Our observations are in good agreement with the forecasts of Barcelona Supercomputing Center, concerning Saharan dust transport.

  12. Evaluation of atmospheric aerosol and tropospheric ozone effects on global terrestrial ecosystem carbon dynamics

    NASA Astrophysics Data System (ADS)

    Chen, Min

    The increasing human activities have produced large amounts of air pollutants ejected into the atmosphere, in which atmospheric aerosols and tropospheric ozone are considered to be especially important because of their negative impacts on human health and their impacts on global climate through either their direct radiative effect or indirect effect on land-atmosphere CO2 exchange. This dissertation dedicates to quantifying and evaluating the aerosol and tropospheric ozone effects on global terrestrial ecosystem dynamics using a modeling approach. An ecosystem model, the integrated Terrestrial Ecosystem Model (iTem), is developed to simulate biophysical and biogeochemical processes in terrestrial ecosystems. A two-broad-band atmospheric radiative transfer model together with the Moderate-Resolution Imaging Spectroradiometer (MODIS) measured atmospheric parameters are used to well estimate global downward solar radiation and the direct and diffuse components in comparison with observations. The atmospheric radiative transfer modeling framework were used to quantify the aerosol direct radiative effect, showing that aerosol loadings cause 18.7 and 12.8 W m -2 decrease of direct-beam Photosynthetic Active Radiation (PAR) and Near Infrared Radiation (NIR) respectively, and 5.2 and 4.4 W m -2 increase of diffuse PAR and NIR, respectively, leading to a total 21.9 W m-2 decrease of total downward solar radiation over the global land surface during the period of 2003-2010. The results also suggested that the aerosol effect may be overwhelmed by clouds because of the stronger extinction and scattering ability of clouds. Applications of the iTem with solar radiation data and with or without considering the aerosol loadings shows that aerosol loading enhances the terrestrial productions [Gross Primary Production (GPP), Net Primary Production (NPP) and Net Ecosystem Production (NEP)] and carbon emissions through plant respiration (RA) in global terrestrial ecosystems over the

  13. Surface ozone-aerosol behaviour and atmospheric boundary layer structure in Saharan dusty scenario

    NASA Astrophysics Data System (ADS)

    Adame, Jose; Córdoba-Jabonero, Carmen; Sorrribas, Mar; Gil-Ojeda, Manuel; Toledo, Daniel; Yela, Margarita

    2016-04-01

    A research campaign was performed for the AMISOC (Atmospheric Minor Species relevant to the Ozone Chemistry) project at El Arenosillo observatory (southwest Spain) in May-June 2012. The campaign focused on the impact of Saharan dust intrusions at the Atmospheric Boundary Layer (ABL) and ozone-aerosol interactions. In-situ and remote-sensing techniques for gases and aerosols were used moreover to modelling analyses. Meteorology features, ABL structures and evolution, aerosol profiling distributions and aerosol-ozone interactions on the surface were analysed. Two four-day periods were selected according to non-dusty (clean conditions) and dusty (Saharan dust) situations. In both scenarios, sea-land breezes developed in the lower atmosphere, but differences were found in the upper levels. Results show that surface temperatures were greater than 3°C and humidity values were lower during dusty conditions than non-dusty conditions. Thermal structures on the surface layer (estimated using an instrument on a 100 m tower) show differences, mainly during nocturnal periods with less intense inversions under dusty conditions. The mixing layer during dusty days was 400-800 m thick, less than observed on non-dusty days. Dust also disturbed the typical daily ABL evolution. Stable conditions were observed during the early evening during intrusions. Aerosol extinction on dusty days was 2-3 times higher, and the dust was confined between 1500 and 5500 m. Back trajectory analyses confirmed that the dust had an African origin. On the surface, the particle concentration was approximately 3.5 times higher during dusty events, but the local ozone did not exhibit any change. The arrival of Saharan dust in the upper levels impacted the meteorological surface, inhibited the daily evolution of the ABL and caused an increase in aerosol loading on the surface and at higher altitudes; however, no dust influence was observed on surface ozone.

  14. iSPEX: everybody can measure atmospheric aerosols with a smartphone spectropolarimeter

    NASA Astrophysics Data System (ADS)

    Snik, F.; Heikamp, S.; de Boer, J.; Keller, C. U.; van Harten, G.; Smit, J. M.; Rietjens, J. H. H.; Hasekamp, O.; Stam, D. M.; Volten, H.; iSPEX Team

    2012-04-01

    An increasing amount people carry a mobile phone with internet connection, camera and large computing power. iSPEX, a spectropolarimetric add-on with complementary app, instantly turns a smartphone into a scientific instrument to measure dust and other aerosols in our atmosphere. A measurement involves scanning the blue sky, which yields the angular behavior of the degree of linear polarization as a function of wavelength, which can unambiguously be interpreted in terms of size, shape and chemical composition of the aerosols in the sky directly above. The measurements are tagged with location and pointing information, and submitted to a central database where they will be interpreted and compiled into an aerosol map. Through crowdsourcing, many people will thus be able to contribute to a better assessment of health risks of particulate matter and of whether or not volcanic ash clouds are dangerous for air traffic. It can also contribute to the understanding of the relationship between atmospheric aerosols and climate change. We will give a live presentation of the first iSPEX prototype. Furthermore, we will present the design and the plans for producing the iSPEX add-on, app and website. We aim to distribute thousands of iSPEX units, such that a unique network of aerosol measurement equipment is created. Many people will thus contribute to the solution of several urgent social and scientific problems, and learn about the nature of light, remote sensing and the issues regarding atmospheric aerosols in the process. In particular we focus on school classes where smartphones are usually considered a nuisance, whereas now they can be a crucial part of various educational programs in science class.

  15. Photochemical aerosol formation in planetary atmospheres: A comparison between Pluto and Titan

    NASA Astrophysics Data System (ADS)

    Lavvas, Panayotis; Strobel, Darrell F.; Lellouch, Emmanuel; Gurwell, Mark A.; Cheng, Andrew F.; Summers, Michael; Gladstone, Randy

    2016-10-01

    The New Horizons mission observations have revealed us that Pluto's atmosphere is rich in photochemical hazes that extend to high altitudes above its surface [1], apparently similar to those observed in Titan's atmosphere [2].We use detailed models combining photochemistry and microphysics in order to simulate the aerosol formation and growth in Pluto's atmosphere, as performed for Titan's atmosphere [3]. Here we discuss the possible mechanisms leading to the formation of haze particles in Pluto's atmosphere, and we evaluate the contribution of different growth processes (e.g. coagulation vs. condensation) to the resulting particle properties.Moreover we investigate the role of these particles in the radiative balance of Pluto's atmosphere and we compare the resulting particle properties, with those retrieved for Titan's upper atmosphere based on Cassini observations [4]. We discuss the similarities and difference between Pluto's and Titan's aerosols.[1] Gladstone et al., 2016, Science, 351, 6271[2] West et al., 2015, Titan's Haze, in Titan, Interior, Surface, Atmosphere and Space environment, Cambridge University Press[3] Lavvas et al., 2013, PNAS, pnas.1217059110[4] Lavvas et al., 2015, DPS47, id.205.08

  16. Adsorption of HO(x) on aerosol surfaces - Implications for the atmosphere of Mars

    NASA Technical Reports Server (NTRS)

    Anbar, A. D.; Leu, M.-T.; Nair, H. A.; Yung, Y. L.

    1993-01-01

    The potential impact of heterogeneous chemistry on the abundance and distribution of HO(x) in the Martian atmosphere is investigated using observational data on dust and ice aerosol distributions combined with an updated photochemical model. Critical parameters include the altitude distributions of aerosols and the surface loss coefficients of HO2 on dust and ice in the lower atmosphere and of H on ice above 40 km. Results of calculations indicate that adsorption of HO2 on dust, or ice near 30 km, can deplete OH abundances in the lower atmosphere by 10 percent or more and that the adsorption of H on ice at 50 km can result in even larger OH depletions (this effect is localized to altitudes greater than 40 km, where CO oxidation is relatively unimportant).

  17. Variability in morphology, hygroscopicity, and optical properties of soot aerosols during atmospheric processing

    PubMed Central

    Zhang, Renyi; Khalizov, Alexei F.; Pagels, Joakim; Zhang, Dan; Xue, Huaxin; McMurry, Peter H.

    2008-01-01

    The atmospheric effects of soot aerosols include interference with radiative transfer, visibility impairment, and alteration of cloud formation and are highly sensitive to the manner by which soot is internally mixed with other aerosol constituents. We present experimental studies to show that soot particles acquire a large mass fraction of sulfuric acid during atmospheric aging, considerably altering their properties. Soot particles exposed to subsaturated sulfuric acid vapor exhibit a marked change in morphology, characterized by a decreased mobility-based diameter but an increased fractal dimension and effective density. These particles experience large hygroscopic size and mass growth at subsaturated conditions (<90% relative humidity) and act efficiently as cloud-condensation nuclei. Coating with sulfuric acid and subsequent hygroscopic growth enhance the optical properties of soot aerosols, increasing scattering by ≈10-fold and absorption by nearly 2-fold at 80% relative humidity relative to fresh particles. In addition, condensation of sulfuric acid is shown to occur at a similar rate on ambient aerosols of various types of a given mobility size, regardless of their chemical compositions and microphysical structures. Representing an important mechanism of atmospheric aging, internal mixing of soot with sulfuric acid has profound implications on visibility, human health, and direct and indirect climate forcing. PMID:18645179

  18. Multiple regression method to determine aerosol optical depth in atmospheric column in Penang, Malaysia

    NASA Astrophysics Data System (ADS)

    Tan, F.; Lim, H. S.; Abdullah, K.; Yoon, T. L.; Zubir Matjafri, M.; Holben, B.

    2014-02-01

    Aerosol optical depth (AOD) from AERONET data has a very fine resolution but air pollution index (API), visibility and relative humidity from the ground truth measurements are coarse. To obtain the local AOD in the atmosphere, the relationship between these three parameters was determined using multiple regression analysis. The data of southwest monsoon period (August to September, 2012) taken in Penang, Malaysia, was used to establish a quantitative relationship in which the AOD is modeled as a function of API, relative humidity, and visibility. The highest correlated model was used to predict AOD values during southwest monsoon period. When aerosol is not uniformly distributed in the atmosphere then the predicted AOD can be highly deviated from the measured values. Therefore these deviated data can be removed by comparing between the predicted AOD values and the actual AERONET data which help to investigate whether the non uniform source of the aerosol is from the ground surface or from higher altitude level. This model can accurately predict AOD if only the aerosol is uniformly distributed in the atmosphere. However, further study is needed to determine this model is suitable to use for AOD predicting not only in Penang, but also other state in Malaysia or even global.

  19. Variability in morphology, hygroscopicity, and optical properties of soot aerosols during atmospheric processing.

    PubMed

    Zhang, Renyi; Khalizov, Alexei F; Pagels, Joakim; Zhang, Dan; Xue, Huaxin; McMurry, Peter H

    2008-07-29

    The atmospheric effects of soot aerosols include interference with radiative transfer, visibility impairment, and alteration of cloud formation and are highly sensitive to the manner by which soot is internally mixed with other aerosol constituents. We present experimental studies to show that soot particles acquire a large mass fraction of sulfuric acid during atmospheric aging, considerably altering their properties. Soot particles exposed to subsaturated sulfuric acid vapor exhibit a marked change in morphology, characterized by a decreased mobility-based diameter but an increased fractal dimension and effective density. These particles experience large hygroscopic size and mass growth at subsaturated conditions (<90% relative humidity) and act efficiently as cloud-condensation nuclei. Coating with sulfuric acid and subsequent hygroscopic growth enhance the optical properties of soot aerosols, increasing scattering by approximately 10-fold and absorption by nearly 2-fold at 80% relative humidity relative to fresh particles. In addition, condensation of sulfuric acid is shown to occur at a similar rate on ambient aerosols of various types of a given mobility size, regardless of their chemical compositions and microphysical structures. Representing an important mechanism of atmospheric aging, internal mixing of soot with sulfuric acid has profound implications on visibility, human health, and direct and indirect climate forcing.

  20. Calmness of the aerosol layer in the atmosphere during biomass burning episodes

    NASA Astrophysics Data System (ADS)

    Silva, A. A.

    2006-06-01

    The aerosol optical depth (AOD) in the atmosphere has been retrieved from direct Sun (DS) measurements by the application of the Beer law (BL). On the other hand, the Langley method (LM), an offspring of the BL, is inappropriate to the retrieval of the AOD since it requires a stable atmosphere during DS measurements, a condition hardly achieved in typical turbulent scenes of biomass burning sites owing to the aerosol layer variability. In this work, some events of calmness of the aerosol layer during biomass burning episodes in the central area of Brazil are identified. Such a condition can be identified by low variability in the AOD values, and it makes the BL and the LM application yield similar results. Intervals of almost 2 hours have been identified, characterizing a state of calmness in the aerosol layer according to the chosen parameters. Measurement restrictions and statistical criteria for the retrieval of the AOD are used in the identification of the calmness states, and as a spin-off the retrieval of the irradiance at the top of the atmosphere (the extrapolated value Ioλ) from the LM has been improved, reducing its uncertainty from 0.5988 × 107 to 0.1878 × 107 photons/s (p/s) at 306.3 nm and from 0.4002 × 107 to 0.1375 × 107 p/s at 320.1 nm. Consequently, the AOD uncertainty has also been reduced by 47 and 56%, respectively, on average.

  1. Aerosol and Cloud-Nucleating Particle Observations during an Atmospheric River Event

    NASA Astrophysics Data System (ADS)

    DeMott, P. J.; McCluskey, C. S.; Petters, M.; Suski, K. J.; Levin, E. J.; Hill, T. C. J.; Atwood, S. A.; Schill, G. P.; Rocci, K.; Boose, Y.; Martin, A.; Cornwell, G.; Al-Mashat, H.; Moore, K.; Prather, K. A.; Rothfuss, N.; Taylor, H.; Leung, L. R.; Tomlinson, J. M.; Mei, F.; Hubbe, J. M.; Rosenfeld, D.; Spackman, J. R.; Fairall, C. W.; Creamean, J.; White, A. B.; Kreidenweis, S. M.

    2015-12-01

    The multi-agency CalWater 2015 project occurred over North Central CA and the Eastern Pacific during January to March 2015 (Spackman et al., this session). The goals of the campaign were to document the structure of atmospheric rivers (ARs) that deliver much of the water vapor associated with major winter storms along the U.S. West Coast and to investigate the modulating effect of aerosols on precipitation. Aerosol sources that may influence orographic cloud properties for air lifted over the mountains in California in winter include pollution, biomass burning, soil dusts and marine aerosols, but their roles will also be influenced by transport, vertical stratification, and scavenging processes. We present results from a comprehensive study of aerosol distributions, compositions, and cloud nucleating properties during an intense winter storm during February 2015, including data from an NSF-supported measurement site at Bodega Bay, from the DOE-ARM Cloud Aerosol Precipitation Experiment that included sampling on the NOAA RV Ron Brown offshore and the G-1 aircraft over ocean and land, and with context provided by other NOAA aircraft and remote sensing facilities. With a special focus on the coastal site, we discuss changes in aerosol distributions, aerosol hygroscopicity, and number concentrations of fluorescent particles, cloud condensation nuclei (CCN), and ice nucleating particles (INPs) during the AR event. We compare with periods preceding and following the event. For example, total aerosol number and surface area concentrations at below 0.5 μm diameter decreased from typical values of a few thousand cm-3 and 100 μm2 cm-3, respectively, to a few hundred cm-3 and 10 μm2cm-3 at Bodega Bay during the AR event. CCN concentrations were similarly lower, but hygroscopicity parameter (kappa) increased from typical values of 0.2 to values > 0.5 during the AR.INP and fluorescent particle number concentrations were generally lower during the AR event than at any other

  2. Effects of atmospheric dynamics and aerosols on the fraction of supercooled water clouds

    NASA Astrophysics Data System (ADS)

    Li, Jiming; Lv, Qiaoyi; Zhang, Min; Wang, Tianhe; Kawamoto, Kazuaki; Chen, Siyu; Zhang, Beidou

    2017-02-01

    Based on 8 years of (January 2008-December 2015) cloud phase information from the GCM-Oriented Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) Cloud Product (GOCCP), aerosol products from CALIPSO and meteorological parameters from the ERA-Interim products, the present study investigates the effects of atmospheric dynamics on the supercooled liquid cloud fraction (SCF) during nighttime under different aerosol loadings at global scale to better understand the conditions of supercooled liquid water gradually transforming to ice phase. Statistical results indicate that aerosols' effect on nucleation cannot fully explain all SCF changes, especially in those regions where aerosols' effect on nucleation is not a first-order influence (e.g., due to low ice nuclei aerosol frequency). By performing the temporal and spatial correlations between SCFs and different meteorological factors, this study presents specifically the relationship between SCF and different meteorological parameters under different aerosol loadings on a global scale. We find that the SCFs almost decrease with increasing of aerosol loading, and the SCF variation is closely related to the meteorological parameters but their temporal relationship is not stable and varies with the different regions, seasons and isotherm levels. Obviously negative temporal correlations between SCFs versus vertical velocity and relative humidity indicate that the higher vertical velocity and relative humidity the smaller SCFs. However, the patterns of temporal correlation for lower-tropospheric static stability, skin temperature and horizontal wind are relatively more complex than those of vertical velocity and humidity. For example, their close correlations are predominantly located in middle and high latitudes and vary with latitude or surface type. Although these statistical correlations have not been used to establish a certain causal relationship, our results may provide a unique point of view

  3. Developing a new parameterization framework for the heterogeneous ice nucleation of atmospheric aerosol particles

    NASA Astrophysics Data System (ADS)

    Ullrich, Romy; Hiranuma, Naruki; Hoose, Corinna; Möhler, Ottmar; Niemand, Monika; Steinke, Isabelle; Wagner, Robert

    2014-05-01

    Developing a new parameterization framework for the heterogeneous ice nucleation of atmospheric aerosol particles Ullrich, R., Hiranuma, N., Hoose, C., Möhler, O., Niemand, M., Steinke, I., Wagner, R. Aerosols of different nature induce microphysical processes of importance for the Earth's atmosphere. They affect not only directly the radiative budget, more importantly they essentially influence the formation and life cycles of clouds. Hence, aerosols and their ice nucleating ability are a fundamental input parameter for weather and climate models. During the previous years, the AIDA (Aerosol Interactions and Dynamics in the Atmosphere) cloud chamber was used to extensively measure, under nearly realistic conditions, the ice nucleating properties of different aerosols. Numerous experiments were performed with a broad variety of aerosol types and under different freezing conditions. A reanalysis of these experiments offers the opportunity to develop a uniform parameterization framework of ice formation for many atmospherically relevant aerosols in a broad temperature and humidity range. The analysis includes both deposition nucleation and immersion freezing. The aim of this study is to develop this comprehensive parameterization for heterogeneous ice formation mainly by using the ice nucleation active site (INAS) approach. Niemand et al. (2012) already developed a temperature dependent parameterization for the INAS- density for immersion freezing on desert dust particles. In addition to a reanalysis of the ice nucleation behaviour of desert dust (Niemand et al. (2012)), volcanic ash (Steinke et al. (2010)) and organic particles (Wagner et al. (2010,2011)) this contribution will also show new results for the immersion freezing and deposition nucleation of soot aerosols. The next step will be the implementation of the parameterizations into the COSMO- ART model in order to test and demonstrate the usability of the framework. Hoose, C. and Möhler, O. (2012) Atmos

  4. Atmospheric lidar research applying to H2O, O2 and aerosols

    NASA Technical Reports Server (NTRS)

    Mcilrath, T. J.; Wilkerson, T. D.

    1977-01-01

    Experimental research on a near infrared tunable dye laser was reported, and theoretical simulations were presented for various lidar configurations. The visible and nearinfrared wavelengths considered were suitable for observations of aerosols, water vapor, molecular oxygen pressure and temperature in the troposphere and above. The first phase of development work was described on a ruby pumped, tunable dye laser for the wavelength region 715 to 740 nanometers. Lidar simulations were summarized for measurements of H2O and for two color lidar observations of aerosols in the atmosphere.

  5. Effect of tropospheric aerosols upon atmospheric infrared cooling rates

    NASA Technical Reports Server (NTRS)

    Harshvardhan, MR.; Cess, R. D.

    1978-01-01

    An investigation has been made of the impact of wind-blown dust particles upon local climate of arid regions. The case of Northwest India is specifically considered, where a dense layer of dust persists for several months during the summer. In order to examine the effect of this dust layer on the infrared radiative flux and cooling rates, a method is presented for calculating the IR flux within a dusty atmosphere which allows the use of gaseous band models and is applicable in the limit of small single scattering albedo and pronounced forward scattering. The participating components of the atmosphere are assumed to be water vapor and spherical quartz particles only. The atmospheric window is partially filled by including the water vapor continuum bands for which empirically obtained transmission functions have been used. It is shown that radically different conclusions may be drawn on dust effects if the continuum absorption is not considered. The radiative transfer model, when applied to a dusty atmosphere, indicates that there is a moderate enhancement in the atmospheric greenhouse and a 10% increase in the mean IR radiative cooling rate, relative to the dust free case, within the lower troposphere. These results have been compared with previous work by other authors in the context of the possibility of dust layers inhibiting local precipitation.

  6. The impact of marine aerosols on atmospheric characteristics over ocean surface in frontal zones

    NASA Astrophysics Data System (ADS)

    Pavlova, Hanna; Palamarchuk, Iuliia; Ruban, Igor; Ivanov, Sergiy

    2015-04-01

    Ocean-derived aerosols are particles produced from the ocean surface and remaining suspended in the atmosphere during a certain period of time. Aerosols act as climate forcers both directly (by scattering and absorbing solar radiation) and indirectly (by affecting cloud microphysics as cloud condensation nuclei). To evaluate the degree of marine aerosols impact on weather conditions the numerical experiments with the HARMONIE model were conducted with the model domain covering area over the North Atlantic. The results showed that marine aerosols have a significant impact on characteristics of the atmosphere (such as air temperature, specific humidity, precipitation, and vertical velocity) over the ocean surface. The most significant differences occur along the frontal zones with high gradients at all vertical levels in the atmosphere for all variables. Change in radiative fluxes leads to changes in temperature of the atmosphere. These anomalies appear as mesoscale cells of opposite signs alternating each other. It can be assumed that they are formed as a result of a chain of factors. Thus, the absorption and scattering of solar radiation in the upper troposphere during daytime, increasing of moisture content and subsequent increase in thermal inertia of the air, and enhanced greenhouse effect at nighttime are acting in different directions on formation of vertical structure and convection conditions. This leads to a strengthening/weakening of the updrafts and compensatory movements, and eventually to the changes in processes of precipitation formation. Thus, the simulation of weather conditions in frontal zones over the ocean requires considering the effect of the marine aerosols presence.

  7. Relationship Between Aerosol Number Size Distribution and Atmospheric Electric Potential Gradient in an Urban Area

    NASA Astrophysics Data System (ADS)

    Wright, Matthew; Matthews, James; Bacak, Asan; Silva, Hugo; Priestley, Michael; Percival, Carl; Shallcross, Dudley

    2016-04-01

    Small ions are created in the atmosphere by ground based radioactive decay and solar and cosmic radiation ionising the air. The ionosphere is maintained at a high potential relative to the Earth due to global thunderstorm activity, a current from the ionosphere transfers charge back to the ground through the weakly ionised atmosphere. A potential gradient (PG) exists between the ionosphere and the ground that can be measured in fair weather using devices such as an electric field mill. PG is inversely-proportional to the conductivity of the air and therefore to the number of ions of a given electrical mobility; a reduction of air ions will cause an increase of PG. Aerosols in the atmosphere act as a sink of air ions with an attachment rate dependent on aerosol size distribution and ion mobility. These relationships have been used to infer high particulate, and hence pollution, levels in historic datasets of atmospheric PG. A measurement campaign was undertaken in Manchester, UK for three weeks in July and August where atmospheric PG was measured with an electric field mill (JCI131, JCI Chilworth) on a second floor balcony, aerosol size distribution measured with a scanning mobility particle sizer (SMPS, TSI3936), aerosol concentration measured with a condensation particle counter (CPC, Grimm 5.403) and local meteorological measurements taken on a rooftop measurement site ~200 m away. Field mill and CPC data were taken at 1 s intervals and SMPS data in 2.5 minute cycles. Data were excluded for one hour either side of rainfall as rainclouds and droplets can carry significant charge which would affect PG. A quantity relating to the attachment of ions to aerosol (Ion Sink) was derived from the effective attachment coefficient of the aerosols. Further measurements with the field mill and CPC were taken at the same location in November 2015 when bonfire events would be expected to increase aerosol concentrations. During the summer measurements, particle number count (PNC

  8. Laboratory Studies of Processing of Carbonaceous Aerosols by Atmospheric Oxidants/Hygroscopicity and CCN Activity of Secondary & Processed Primary Organic Aerosols

    SciTech Connect

    Ziemann, P.J.; Arey, J.; Atkinson, R.; Kreidenweis, S.M.; Petters, M.D.

    2012-06-13

    The atmosphere is composed of a complex mixture of gases and suspended microscopic aerosol particles. The ability of these particles to take up water (hygroscopicity) and to act as nuclei for cloud droplet formation significantly impacts aerosol light scattering and absorption, and cloud formation, thereby influencing air quality, visibility, and climate in important ways. A substantial, yet poorly characterized component of the atmospheric aerosol is organic matter. Its major sources are direct emissions from combustion processes, which are referred to as primary organic aerosol (POA), or in situ processes in which volatile organic compounds (VOCs) are oxidized in the atmosphere to low volatility reaction products that subsequent condense to form particles that are referred to as secondary organic aerosol (SOA). POA and VOCs are emitted to the atmosphere from both anthropogenic and natural (biogenic) sources. The overall goal of this experimental research project was to conduct laboratory studies under simulated atmospheric conditions to investigate the effects of the chemical composition of organic aerosol particles on their hygroscopicity and cloud condensation nucleation (CCN) activity, in order to develop quantitative relationships that could be used to more accurately incorporate aerosol-cloud interactions into regional and global atmospheric models. More specifically, the project aimed to determine the products, mechanisms, and rates of chemical reactions involved in the processing of organic aerosol particles by atmospheric oxidants and to investigate the relationships between the chemical composition of organic particles (as represented by molecule sizes and the specific functional groups that are present) and the hygroscopicity and CCN activity of oxidized POA and SOA formed from the oxidation of the major classes of anthropogenic and biogenic VOCs that are emitted to the atmosphere, as well as model hydrocarbons. The general approach for this project was

  9. Characterisation of bio-aerosols during dust storm period in N-NW India

    NASA Astrophysics Data System (ADS)

    Yadav, Sudesh; Chauhan, M. S.; Sharma, Anupam

    Bio-investigations for pollen and spores were performed on dry free-fall dust and PM 10 aerosol samples, collected from three different locations separated by a distance of 600 km, situated in dust storm hit region of N-NW India. Presence of pollen of trees namely Prosopis ( Prosopis juliflora and Prosopis cinearia), Acacia, Syzygium, Pinus, Cedrus, Holoptelea and shrubs namely Ziziphus, Ricinus, Ephedra and members of Fabaceae, Oleaceae families was recorded but with varying proportions in the samples of different locations. Poaceae, Chenopodiaceae/Amaranthaceae, Caryophyllaceae, Brassicaceae and Cyperaceae (sedges) were some of the herb pollen identified in the samples. Among the fungal spores Nigrospora was seen in almost all samples. Nigrospora is a well known allergen and causes health problems. The concentration of trees and shrubs increases in the windward direction just as the climate changes from hot arid to semiarid. The higher frequency of grasses (Poaceae) or herbs could either be a result of the presence of these herbs in the sampling area and hence the higher production of pollen/spores or due to the resuspension from the exposed surface by the high-intensity winds. But we cannot ascertain the exact process at this stage. The overall similarity in the pollen and spore assemblage in our dust samples indicates a common connection or source(s) to the dust in this region. Presence of the pollen of the species of Himalayan origin in our entire samples strongly point towards a Himalayan connection, could be direct or indirect, to the bioaerosols and hence dust in N-NW India. In order to understand the transport path and processes involved therein, present study needs further extension with more number of samples and with reference to meteorological parameters.

  10. Thermal Emission Spectrometer Results: Mars Atmospheric Thermal Structure and Aerosol Distribution

    NASA Technical Reports Server (NTRS)

    Smith, Michael D.; Pearl, John C.; Conrath, Barney J.; Christensen, Philip R.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Infrared spectra returned by the Thermal Emission Spectrometer (TES) are well suited for retrieval of the thermal structure and the distribution of aerosols in the Martian atmosphere. Combined nadir- and limb-viewing spectra allow global monitoring of the atmosphere up to 0.01 mbar (65 km). We report here on the atmospheric thermal structure and the distribution of aerosols as observed thus far during the mapping phase of the Mars Global Surveyor mission. Zonal and temporal mean cross sections are used to examine the seasonal evolution of atmospheric temperatures and zonal winds during a period extending from northern hemisphere mid-summer through vernal equinox (L(sub s) = 104-360 deg). Temperature maps at selected pressure levels provide a characterization of planetary-scale waves. Retrieved atmospheric infrared dust opacity maps show the formation and evolution of regional dust storms during southern hemisphere summer. Response of the atmospheric thermal structure to the changing dust loading is observed. Maps of water-ice clouds as viewed in the thermal infrared are presented along with seasonal trends of infrared water-ice opacity. Uses of these observations for diagnostic studies of the dynamics of the atmosphere are discussed.

  11. Power Spectral Densities of Atmospheric Aerosol Particle Counts

    DTIC Science & Technology

    2010-01-01

    directly by absorbing and scattering radiation and indirectly by acting as cloud condensation nuclei (CCN). They are also important in atmospheric...are generated photochemically from vapor-phase terpenes emitted by plants; and combustion-generated particles from vehicular traffic, biomass

  12. Multiwavelength micropulse lidar in atmospheric aerosol study: signal processing

    NASA Astrophysics Data System (ADS)

    Posyniak, Michal; Malinowski, Szymon P.; Stacewicz, Tadeusz; Markowicz, Krzysztof M.; Zielinski, Tymon; Petelski, Tomasz; Makuch, Przemyslaw

    2011-11-01

    Multiwavelength micropulse lidar (MML) designed for continuous optical sounding of the atmosphere is presented. A specific signal processing technique applying two directional Kalman filtering is introduced in order to enhance signal to noise ratio. Application of this technique is illustrated with profiles collected in course of COAST 2009 and WRNP 2010 research campaigns.

  13. Sampling, characterization, and remote sensing of aerosols formed in the atmospheric hydrolysis of uranium hexafluoride

    SciTech Connect

    Bostick, W.D.; McCulla, W.H.; Pickrell, P.W.

    1984-05-01

    When gaseous uranium hexafluoride (UF/sub 6/) is released into the atmosphere, it rapidly reacts with ambient moisture to form an aerosol of uranyl fluoride (UO/sub 2/F/sub 2/) and hydrogen fluoride (HF). As part of our Safety Analysis program, we have performed several experimental releases of HF/sub 6/ in contained volumes in order to investigate techniques for sampling and characterizing the aerosol materials. The aggregate particle morphology and size distribution have been found to be dependent upon several conditions, including the temperature of the UF/sub 6/ at the time of its release, the relative humidity of the air into which it is released, and the elapsed time after the release. Aerosol composition and settling rate have been investigated using stationary samplers for the separate collection of UO/sub 2/F/sub 2/ and HF and via laser spectroscopic remote sensing (Mie scatter and infrared spectroscopy). 25 refs., 16 figs., 5 tabs.

  14. Nuclear Emergency and the Atmospheric Dispersion of Nuclear Aerosols: Discussion of the Shared Nuclear Future - 13163

    SciTech Connect

    Rana, Mukhtar A.; Ali, Nawab; Akhter, Parveen; Khan, E.U.

    2013-07-01

    This paper has a twofold objective. One is to analyze the current status of high-level nuclear waste disposal along with presentation of practical perspectives about the environmental issues involved. Present disposal designs and concepts are analyzed on a scientific basis and modifications to existing designs are proposed from the perspective of environmental safety. Other is to understand the aerosol formation in the atmosphere for the case of the leakage from the nuclear waste containers or a nuclear accident. Radio-nuclides released from the waste will attach themselves to the existing aerosols in the atmosphere along with formation of new aerosols. Anticipating the nuclear accident when a variety of radioactive aerosols will form and exist in the atmosphere, as a simple example, measurement of naturally existing radioactive aerosols are made in the atmosphere of Islamabad and Murree. A comparison with similar measurements in 3 cities of France is provided. Measurement of radionuclides in the atmosphere, their attachment to aerosols and follow up transport mechanisms are key issues in the nuclear safety. It is studied here how {sup 7}Be concentration in the atmospheric air varies in the capital city of Islamabad and a Himalaya foothill city of Murree (Pakistan). Present results are compared with recent related published results to produce a {sup 7}Be concentration versus altitude plot up to an altitude of 4000 m (a.s.l.). Origin and variance of {sup 7}Be concentration at different altitudes is discussed in detail. The relevance of results presented here with the evaluation of implications of Chernobyl and Fukushima nuclear disasters has been discussed in a conclusive manner. It is the first international report of a joint collaboration/project. The project is being generalized to investigate and formulate a smooth waste storage and disposal policy. The project will address the fission and fusion waste reduction, its storage, its recycling, air, water and soil

  15. Investigation of anthropogenic-origin-metals in the atmospheric aerosols collected at Cape Hedo, Okinawa, Japan

    NASA Astrophysics Data System (ADS)

    Murayama, H.; Azechi, S.; Tsuhako, A.; Miyagi, Y.; Kasaba, T.; Arakaki, T.

    2014-12-01

    Atmospheric aerosols are important to atmospheric chemistry, and affect our lives. Aerosols include fine particles, which consist of inorganic compounds, organic substances, heavy metals, etc. Aerosols can be roughly separated into natural and anthropogenic origins. For example, natural origins include wind-blown sea-salt, Asian dust (called Kosa in Japan), etc. Anthropogenic origins include burning of fossil fuel and agricultural biomass, automobiles, industrial activities, etc. In Japan, Kosa is the most well-known aerosol. This study investigated anthropogenic-origin-metals present in the aerosols. Aerosol samples were collected at Cape Hedo Atmospheric Aerosol Monitoring Station (CHAAMS) in Okinawa Island, Japan with a high volume air sampler. Samples analyzed for this study were collected between January 2008 and August 2014. A 1/8 of aerosol filter was digested by the mixture of acids and oxidant (nitric acid/hydrogen fluoride/hydrogen peroxide). The sample was filtered by 0.45 μm membrane filter before analyses. Metal ion concentrations were measured by atomic absorption spectrophotometry (Na, Mg, K) and inductively-coupled plasma mass spectrometer (Al, Fe, Ca, Ti, Mn, V, Cu, Cd, Zn, Pb). Air mass movement was analyzed by NOAA's HYSPRIT model. Results showed that concentrations of heavy metals were high during winter and spring, and the lowest in summer. V/Mn ratios were used as an indicator for heavy oil burning. High V/Mn ratios were observed during maritime air mass periods. On the other hand, Pb/Zn ratio was used as an indicator for leaded gasoline usage, which was high when air mass was coming from Asian continent during winter and spring. Average Pb/Zn ratio was 0.65. Non-sea-salt K (nss-K) was used as an indicator for biomass burning, and showed good correlation with total organic carbon (TOC) concentrations. However, nss-K and crustal-origin-metals also showed good correlation. Thus, we have to be careful when considering whether nss-K is from

  16. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India.

    PubMed

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500nm are found to be 0.47±0.09, 0.34±0.08, 0.29±0.06 and 0.30±0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α380-1020) value is observed maximum in March (1.25±0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33±0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00-08:00 (IST) and evening 19:00-21:00 (IST) hours and one minima noticed during afternoon (13:00-16:00). The highest monthly mean BC concentration is observed in the month of January (3.4±1.2μgm(-3)) and the lowest in July (1.1±0.2μgm(-3)). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be +36.8±1.7Wm(-2), +26.9±0.2Wm(-2), +18.0±0.6Wm(-2) and +18.5±3.1Wm(-2) during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80Wm(-2)) which contributes more increase in atmospheric heating by ~1K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating.

  17. Physicochemical and Toxicological Characteristics of Semi-volatile Components of Atmospheric Aerosols in an Urban Environment

    NASA Astrophysics Data System (ADS)

    Verma, V.; Pakbin, P.; Cheung, K. L.; Cho, A. K.; Schauer, J. J.; Shafer, M. M.; Kleinman, M. T.; Sioutas, C.

    2010-12-01

    Recent toxicological studies have confirmed the oxidative properties of atmospheric aerosols and their capability to generate reactive oxygen species (ROS) in biological systems (Chen and Lippmann, 2009). While the links between aerosol toxicity and refractory transition metals present in ambient particulate matter (PM) have been documented, there are limited studies investigating the oxidative characteristics of semi-volatile species. The goal of present study is to examine the contribution of semi-volatile compounds in the oxidative potential of atmospheric aerosols. Concentrated ambient and thermodenuded quasi-ultrafine particles (<180 nm) were collected using the versatile aerosol concentration enrichment system (VACES) at an urban site near downtown Los Angeles. A thermodenuder (TD) was used to selectively remove the semi-volatile components of these aerosols over the temperature range of 50-200 oC. The oxidative potential of PM was measured by means of the DTT (dithiothreitol) assay. Detailed chemical analyses of PM samples, including organic and elemental carbon, water soluble elements, inorganic ions and polycyclic aromatic hydrocarbons (PAHs), were conducted to quantify the volatility profiles of different PM species, and also to investigate their effect on the measured oxidative potential. Refractory constituents, such as metals and elemental carbon, were marginally affected by heating, while labile species such as organic carbon and PAHs showed progressive loss in concentration with increase in TD temperature. The DTT-measured oxidative potential of PM was significantly decreased as the aerosols were heated and their semi-volatile components were progressively removed (42 %, 47 % and 66 % decrease in DTT activity at 50, 100 and 200 oC, respectively). Regression analysis performed between chemical constituents and DTT activity showed that the oxidative potential was strongly correlated with organic carbon and PAHs (R≥0.80; p≤0.05). Thus, semi

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

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

  19. XUV complex refractive indices of aerosols in the atmospheres of Titan and the primitive Earth

    NASA Astrophysics Data System (ADS)

    Gavilan, Lisseth; Neumann, Maciej; Bulkin, Pavel; Popescu, Horia; Steffan, Martin; Esser, Norbert; Carrasco, Nathalie

    2016-10-01

    The complex refractive indices of tholins, simulating aerosols in the atmosphere of Titan and the primitive earth, have been measured over a wide spectral range, including the soft X-ray, vacuum-ultraviolet (VUV), and UV-Visible. The soft X-ray and VUV spectral ranges are in particular relevant to radiative transfer models of solar irradiation of primitive atmospheres (Lammer et al. 2008) and may elucidate the (anti-)greenhouse potential of photochemical aerosols.Thin films were grown using the PAMPRE capacitively coupled plasma setup (Szopa et al. 2006; Carrasco et al. 2009). Gas mixtures consisting of CH4/N2 with 5:95 ratios were used to simulate Titan's atmospheric composition. For the primitive Earth, gas mixtures of N2/CO2/H2 and N2/CO2/CH4 were used as described in Fleury et al. (2014).State-of-the-art laboratory techniques were used to determine the refractive indices of such tholin films. These include VUV ellipsometry (performed in collaboration with the Metrology Light Source in Berlin) and synchrotron X-ray spectroscopy (performed at the SEXTANTS beamline of the SOLEIL synchrotron). While VUV spectroscopy reveals new electronic transitions due to plasmon resonances in tholins, X-ray spectra reveal the C and O absorption edges of these solids. The refractive indices are compared to results from Khare et al. (1984). Implications on the optical properties of these aerosol analogs on the radiative modeling of primitive atmospheres will be discussed.

  20. Detailed Chemical Characterization of Unresolved Complex Mixtures (UCM) inAtmospheric Organics: Insights into Emission Sources, Atmospheric Processing andSecondary Organic Aerosol Formation

    EPA Science Inventory

    Recent studies suggest that semivolatile organic compounds (SVOCs) are important precursors to secondary organic aerosol (SOA) in urban atmospheres. However, knowledge of the chemical composition of SVOCs is limited by current analytical techniques, which are typically unable to...

  1. Aerosols

    Atmospheric Science Data Center

    2013-04-17

    ... article title:  Aerosols over Central and Eastern Europe     View Larger Image ... last weeks of March 2003, widespread aerosol pollution over Europe was detected by several satellite-borne instruments. The Multi-angle ...

  2. Deriving aerosol properties from measurements of the Atmosphere-Surface Radiation Automatic Instrument (ASRAI)

    NASA Astrophysics Data System (ADS)

    Xu, Hua; Li, Donghui; Li, Zhengqiang; Zheng, Xiaobing; Li, Xin; Xie, Yisong; Liu, Enchao

    2015-10-01

    The Atmosphere-surface Radiation Automatic Instrument (ASRAI) is a newly developed hyper-spectral apparatus by Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (AIOFM, CAS), measuring total spectral irradiance, diffuse spectral irradiance of atmosphere and reflected radiance of the land surface for the purpose of in-situ calibration. The instrument applies VIS-SWIR spectrum (0.4~1.0 μm) with an averaged spectral resolution of 0.004 μm. The goal of this paper is to describe a method of deriving both aerosol optical depth (AOD) and aerosol modes from irradiance measurements under free cloudy conditions. The total columnar amounts of water vapor and oxygen are first inferred from solar transmitted irradiance at strong absorption wavelength. The AOD together with total columnar amounts of ozone and nitrogen dioxide are determined by a nonlinear least distance fitting method. Moreover, it is able to infer aerosol modes from the spectral dependency of AOD because different aerosol modes have their inherent spectral extinction characteristics. With assumption that the real aerosol is an idea of "external mixing" of four basic components, dust-like, water-soluble, oceanic and soot, the percentage of volume concentration of each component can be retrieved. A spectrum matching technology based on Euclidean-distance method is adopted to find the most approximate combination of components. The volume concentration ratios of four basic components are in accordance with our prior knowledge of regional aerosol climatology. Another advantage is that the retrievals would facilitate the TOA simulation when applying 6S model for satellite calibration.

  3. Aerosol ion concentration dependence on atmospheric conditions in Chicago

    NASA Astrophysics Data System (ADS)

    Fosco, Tinamarie; Schmeling, Martina

    This study seeks to determine the influence of precursor trace gases and local meteorology, including lake breeze events, on the concentrations of secondary aerosol species in Chicago. For this, two particulate air samples per day were collected onto quartz fiber filters at the Loyola University Chicago Air Station (LUCAS) during the summer months of 2002 and 2003 and subsequently analyzed by ion chromatography for sulfate, nitrate and oxalate. In parallel, mixing ratios of ozone (O 3) and nitrogen oxides (NO and NO 2dbnd NO x) were monitored and weather parameters were recorded. In addition, backward trajectories were obtained to estimate air mass transport to Chicago. Ozone and NO x mixing ratios as well as sulfate, nitrate and oxalate concentrations varied substantially throughout the study, but three situations could be distinguished based on meteorology and chemistry. Case one had the lowest ozone, NO x and ion levels due to wind directions constantly from Lake Michigan. Case two comprised of days showing the highest pollutant levels because of to predominantly southwestern air currents and warm temperatures and case three experienced an air stagnation situation in the morning leading to high NO x mixing ratios and a subsequent lake breeze event. In the last case, elevated ozone mixing ratios and ion concentrations were observed after lake breeze onset indicating pollutant transport.

  4. Aerosol predictions and their links to weather forecasts through online interactive atmospheric modeling and data assimilation

    NASA Astrophysics Data System (ADS)

    Saide Peralta, Pablo Enrique

    Atmospheric particles represent a component of air pollution that has been identified as a major contributor to adverse health effects and mortality. Aerosols also interact with solar radiation and clouds perturbing the atmosphere and generating responses in a wide range of scales, such as changes to severe weather and climate. Thus, being able to accurately predict aerosols and its effects on atmospheric properties is of upmost importance. This thesis presents a collection of studies with the global objective to advance in science and operations the use of WRF-Chem, a regional model able to provide weather and atmospheric chemistry predictions and simultaneously representing aerosol effects on climate. Different strategies are used to obtain accurate predictions, including finding an adequate model configuration for each application (e.g., grid resolution, parameterizations choices, processes modeled), using accurate forcing elements (e.g., weather and chemical boundary conditions, emissions), and developing and applying data assimilation techniques for different observational sources. Several environments and scales are simulated, including complex terrain at a city scale, meso-scale over the southeast US for severe weather applications, and regional simulations over the three subtropical persistent stratocumulus decks (off shore California and southeast Pacific and Atlantic) and over North America. Model performance is evaluated against a large spectrum of observations, including field experiments and ground based and satellite measurements. Overall, very positive results were obtained with the WRF-Chem system once it had been configured properly and the inputs chosen. Also, data assimilation of aerosol and cloud satellite observations contributed to improve model performance even further. The model is proven to be an excellent tool for forecasting applications, both for local and long range transported pollution. Also, advances are made to better understand

  5. Atmospheric Polarization Imaging with Variable Aerosols and Clouds

    DTIC Science & Technology

    2010-12-10

    to a cloud;  Measurements made at the Mauna Loa Observatory (a mountaintop observatory in Hawaii) confirmed previous studies by Coulson and...on work supported by this grant: 1. Mr. Andrew Dahlberg – All-sky polarization imager deployment at Mauna Loa Observatory , Hawaii – M.S. Thesis...the Mauna Loa Observatory on the island of Hawaii (Dahlberg et al. 2009). The Atmospheric Polarization Imager (API) System The API instrument

  6. Ionization and Aerosol Particulates in the Middle Atmosphere.

    DTIC Science & Technology

    1981-10-01

    ospheric conductivity , and the changes in conductivity produced by la-ps ,uilt into the payloads, .-oth visible and ultraviolet~ DDO 07 1473n 91b9’O.S~O~L...to Northern Ontario in February, 1979 and to Kenya in February, 1980. These payloads used "blunt" conductivity probes to measure atmospheric... conductivity , and the changes in conductivity produced by lamps built into the payloads, both visible and ultraviolet. A prototype was built and launched on a

  7. Uncertainty Analysis And Synergy Of Aerosol Products From Multiple Satellite Sensors For Advanced Atmospheric Research

    NASA Astrophysics Data System (ADS)

    Ichoku, C. M.; Petrenko, M.

    2013-05-01

    Aerosols are tiny particles suspended in the air, and can be made up of wind-blown dust, smoke from fires, and particulate emissions from automobiles, industries, and other natural and man-made sources. Aerosols can have significant impacts on the air quality, and can interact with clouds and solar radiation in such a way as to affect the water cycle and climate. However, the extent and scale of these impacts are still poorly understood, and this represents one of the greatest uncertainties in climate research to date. To fill this gap in our knowledge, the global and local properties of atmospheric aerosols are being extensively observed and measured, especially during the last decade, using both satellite and ground-based instruments, including such spaceborne sensors as MODIS on the Terra and Aqua satellites, MISR on Terra, OMI on Aura, POLDER on PARASOL, CALIOP on CALIPSO, SeaWiFS on SeaStar, and the ground-based Aerosol Robotic Network (AERONET) of sunphotometers. The aerosol measurements collected by these instruments over the last decade contribute to an unprecedented availability of the most complete set of complimentary aerosol measurements ever acquired. Still, to be able to utilize these measurements synergistically, they have to be carefully and uniformly analyzed and inter-compared, in order to understand the uncertainties and limitations of the products - a process that is greatly complicated by the diversity of differences that exist among them. In this presentation, we will show results of a coherent comparative uncertainty analysis of aerosol measurements from the above-named satellite sensors relative to AERONET. We use these results to demonstrate how these sensors perform in different parts of the world over different landcover types as well as their performance relative to one another, thereby facilitating product selection and integration for specific research and applications needs.

  8. Road traffic impact on urban atmospheric aerosol loading at Oporto, Portugal

    NASA Astrophysics Data System (ADS)

    Oliveira, César; Pio, Casimiro; Caseiro, Alexandre; Santos, Patrícia; Nunes, Teresa; Mao, Hongjun; Luahana, Lakhumal; Sokhi, Ranjeet

    2010-08-01

    At urban areas in south Europe atmospheric aerosol levels are frequently above legislation limits as a result of road traffic and favourable climatic conditions for photochemical formation and dust suspension. Strategies for urban particulate pollution control have to take into account specific regional characteristics and need correct information concerning the sources of the aerosol. With these objectives, the ionic and elemental composition of the fine (PM 2.5) and coarse (PM 2.5-10) aerosol was measured at two contrasting sites in the centre of the city of Oporto, roadside (R) and urban background (UB), during two campaigns, in winter and summer. Application of Spatial Variability Factors, in association with Principal Component/Multilinear Regression/Inter-site Mass Balance Analysis, to aerosol data permitted to identify and quantify 5 main groups of sources, namely direct car emissions, industry, photochemical production, dust suspension and sea salt transport. Traffic strongly influenced PM mass and composition. Direct car emissions and road dust resuspension contributed with 44-66% to the fine aerosol and with 12 to 55% to the coarse particles mass at both sites, showing typically highest loads at roadside. In fine particles secondary origin was also quite important in aerosol loading, principally during summer, with 28-48% mass contribution, at R and UB sites respectively. Sea spray has an important contribution of 18-28% to coarse aerosol mass in the studied area, with a highest relative contribution at UB site. Application of Spatial Variability/Mass Balance Analysis permitted the estimation of traffic contribution to soil dust in both size ranges, across sites and seasons, demonstrating that as much as 80% of present dust can result from road traffic resuspension.

  9. Scattering properties of atmospheric aerosols over Lanzhou City and applications using an integrating nephelometer

    NASA Astrophysics Data System (ADS)

    Wu, Zhang; Bo, Hu; Changhe, Chen; Ping, Du; Lei, Zhang; Guanghong, Feng

    2004-12-01

    The data, measured by a three-wavelength Integrating Nephelometer over Lanzhou City during the winters of 2001/2002 and 2002/2003 respectively, have been analyzed for investigating the scattering properties of atmospheric aerosols and exploring their relationship and the status of air pollution. The aerosol particle volume distribution is inverted with the measured spectral scattering coefficients. The results show that the daily variation of the aerosol scattering coefficients is in a tri-peak shape. The average ratio of backscattering coefficient to total scattering coefficient at 550 nm is 0.158; there exists an excellent correlation between the scattering coefficients and the concentration of PM10. The average ratio of the concentration of PM10 to the scattering coefficients is 0.37 g m-2, which is contingent on the optical parameters of aerosol particles such as the size distribution, etc.; an algorithm is developed for inverting the volume distribution of aerosol particles by using the histogram and Monte-Carlo techniques, and the test results show that the inversion is reasonable.

  10. Atmospheric aerosol characterization with a ground-based SPEX spectropolarimetric instrument

    NASA Astrophysics Data System (ADS)

    van Harten, G.; de Boer, J.; Rietjens, J. H. H.; Di Noia, A.; Snik, F.; Volten, H.; Smit, J. M.; Hasekamp, O. P.; Henzing, J. S.; Keller, C. U.

    2014-06-01

    Characterization of atmospheric aerosols is important for understanding their impact on health and climate. A wealth of aerosol parameters can be retrieved from multi-angle, multi-wavelength radiance and polarization measurements of the clear sky. We developed a ground-based SPEX instrument (groundSPEX) for accurate spectropolarimetry, based on the passive, robust, athermal and snapshot spectral polarization modulation technique, and hence ideal for field deployment. It samples the scattering phase function in the principal plane in an automated fashion, using a motorized pan/tilt unit and automatic exposure time detection. Extensive radiometric and polarimetric calibrations were performed, yielding values for both random noise and systematic uncertainties. The absolute polarimetric accuracy at low degrees of polarization is established to be ~ 5 × 10-3. About 70 measurement sequences have been performed throughout four clear-sky days at Cabauw, the Netherlands. Several aerosol parameters were retrieved: aerosol optical thickness, effective radius, and complex refractive index for fine and coarse mode. The results are in good agreement with the co-located AERONET products, with a correlation coefficient of ρ = 0.932 for the total aerosol optical thickness at 550 nm.

  11. Atmospheric aerosol characterization with a ground-based SPEX spectropolarimetric instrument

    NASA Astrophysics Data System (ADS)

    van Harten, G.; de Boer, J.; Rietjens, J. H. H.; Di Noia, A.; Snik, F.; Volten, H.; Smit, J. M.; Hasekamp, O. P.; Henzing, J. S.; Keller, C. U.

    2014-12-01

    Characterization of atmospheric aerosols is important for understanding their impact on health and climate. A wealth of aerosol parameters can be retrieved from multi-angle, multi-wavelength radiance and polarization measurements of the clear sky. We developed a ground-based SPEX instrument (groundSPEX) for accurate spectropolarimetry, based on the passive, robust, athermal, and snapshot spectral polarization modulation technique, and is hence ideal for field deployment. It samples the scattering phase function in the principal plane in an automated fashion, using a motorized pan/tilt unit and automatic exposure time detection. Extensive radiometric and polarimetric calibrations were performed, yielding values for both random noise and systematic uncertainties. The absolute polarimetric accuracy at low degrees of polarization is established to be ~5 × 10-3. About 70 measurement sequences have been performed throughout four clear-sky days at Cabauw, the Netherlands. Several aerosol parameters were retrieved: aerosol optical thickness, effective radius, and complex refractive index for fine and coarse mode. The results are in good agreement with the colocated AERONET products, with a correlation coefficient of ρ = 0.932 for the total aerosol optical thickness at 550 nm.

  12. Multi-Decadal Change of Atmospheric Aerosols and their Effects on Surface Radiation

    NASA Technical Reports Server (NTRS)

    Chin, Mian

    2011-01-01

    We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007) during which a suite of aerosol data from satellite observations) ground-based measurements) and intensive field experiments have become available. We analyze the long-term global and regional aerosol trends and their relationship to the changes of aerosol and precursor emissions and assess the role aerosols play in the multi-decadal change of solar radiation reaching the surface (known as "dimming" or "brightening") at different regions of the world) including the major anthropogenic source regions (North America) Europe) Asia) that have been experiencing considerable changes of emissions) dust and biomass burning regions that have large interannual variabilities) downwind regions that are directly affected by the changes in the source area) and remote regions that are considered to representing "backgroundH conditions.

  13. Characteristics and composition of atmospheric aerosols in Phimai, central Thailand during BASE-ASIA

    NASA Astrophysics Data System (ADS)

    Li, Can; Tsay, Si-Chee; Hsu, N. Christina; Kim, Jin Young; Howell, Steven G.; Huebert, Barry J.; Ji, Qiang; Jeong, Myeong-Jae; Wang, Sheng-Hsiang; Hansell, Richard A.; Bell, Shaun W.

    2013-10-01

    Comprehensive measurements of atmospheric aerosols were made in Phimai, central Thailand (15.183°N, 102.565°E, elevation: 206 m) during the BASE-ASIA field experiment from late February to early May in 2006. The observed aerosol loading was sizable for this rural site (mean aerosol scattering: 108 ± 64 Mm-1; absorption: 15 ± 8 Mm-1; PM10 concentration: 33 ± 17 μg m-3), and dominated by submicron particles. Major aerosol compounds included carbonaceous (OC: 9.5 ± 3.6 μg m-3; EC: 2.0 ± 2.3 μg m-3) and secondary species (SO42-: 6.4 ± 3.7 μg m-3, NH4+: 2.2 ± 1.3 μg m-3). While the site was seldom under the direct influence of large forest fires to its north, agricultural fires were ubiquitous during the experiment, as suggested by the substantial concentration of K+ (0.56 ± 0.33 μg m-3). Besides biomass burning, aerosols in Phimai during the experiment were also strongly influenced by industrial and vehicular emissions from the Bangkok metropolitan region and long-range transport from southern China. High humidity played an important role in determining the aerosol composition and properties in the region. Sulfate was primarily formed via aqueous phase reactions, and hygroscopic growth could enhance the aerosol light scattering by up to 60%, at the typical morning RH level of 85%. The aerosol single scattering albedo demonstrated distinct diurnal variation, ranging from 0.86 ± 0.04 in the evening to 0.92 ± 0.02 in the morning. This experiment marks the first time such comprehensive characterization of aerosols was made for rural central Thailand. Our results indicate that aerosol pollution has developed into a regional problem for northern Indochina, and may become more severe as the region's population and economy continue to grow.

  14. The Influence of Atmospheric Aerosols on Air Quality Status of the Egyptian Nile Delta

    NASA Astrophysics Data System (ADS)

    El-Askary, H. M.; Zakey, A.

    2014-12-01

    Due to the combination of natural and anthropogenic sources of emission over the Nile Delta region, the air quality status is very poor and has a significant health hazards impacts on the population. Here we focused on the optical and chemical characterizations of atmospheric aerosols in the Nile Delta using the online integrated Environmental-Climate Aerosols model (EnvClimA) during a 10 year period 2000-2010. Observations from MODIS and SeaWiFS measurements supplemented by CALIPSO and some ground-based data from AERONET, are used to validate the EnvClimA model and to illustrate the aerosol characteristics and their sources. CALIPSO measurements were used to characterize the vertical structure of aerosols and their shapes (spherical and non-spherical) for major dust storms and biomass burning events. In this study we discussed the synoptic patterns and features, which are associated with either the dust storm or high pollution events. We used MODIS derived aerosol parameters to study seasonal changes in aerosol parameters due to the influence of dust storms, anthropogenic pollution and biomass (crop residue) burning. MODIS derived deep blue AOD provided better representation of aerosol loading over north Africa (Sahara region) along with dark-target AOD and related parameters. AERONET data provided aerosol optical depth, angstrom, fine mode fraction, size fraction, volume, effective radius, refractive index, single scattering albedo, and radiative forcing during different seasons dominated by dust storms, anthropogenic pollution and biomass burning (black cloud phenomena). The results indicated that the observed AOD decreases in the summer and increases again in the fall due to agricultural burning events. Ground-based AERONET data support the "Dark Product" MODIS retrievals, as they typically show a fall peak in the 500 nm region. The number of dust distribution frequencies over Egypt has more frequency in the southeast and northwest of Egypt (5-7.5 days

  15. Mapping atmospheric aerosols with a citizen science network of smartphone spectropolarimeters

    NASA Astrophysics Data System (ADS)

    Snik, Frans; Rietjens, Jeroen H. H.; Apituley, Arnoud; Volten, Hester; Mijling, Bas; Di Noia, Antonio; Heikamp, Stephanie; Heinsbroek, Ritse C.; Hasekamp, Otto P.; Smit, J. Martijn; Vonk, Jan; Stam, Daphne M.; Harten, Gerard; Boer, Jozua; Keller, Christoph U.

    2014-10-01

    To assess the impact of atmospheric aerosols on health, climate, and air traffic, aerosol properties must be measured with fine spatial and temporal sampling. This can be achieved by actively involving citizens and the technology they own to form an atmospheric measurement network. We establish this new measurement strategy by developing and deploying iSPEX, a low-cost, mass-producible optical add-on for smartphones with a corresponding app. The aerosol optical thickness (AOT) maps derived from iSPEX spectropolarimetric measurements of the daytime cloud-free sky by thousands of citizen scientists throughout the Netherlands are in good agreement with the spatial AOT structure derived from satellite imagery and temporal AOT variations derived from ground-based precision photometry. These maps show structures at scales of kilometers that are typical for urban air pollution, indicating the potential of iSPEX to provide information about aerosol properties at locations and at times that are not covered by current monitoring efforts.

  16. Aerosol interactions between the surface and the atmosphere: Urban fluxes, forest canopy vertical exchange, and wintertime urban patterns

    NASA Astrophysics Data System (ADS)

    Grivicke, Rasa

    Atmospheric aerosols play a major role in regional atmospheric chemistry and air quality, while on a global scale, aerosol processes continue to represent the largest source of uncertainty related to climate change. An important aspect of understanding the role of aerosols in these areas is to document the vertical exchange of aerosols with the surface in both urban and rural landscapes since the vertical exchange represents important sources and sinks of aerosols on regional and global scales. In this dissertation, investigation of aerosol dynamics is described for three separate field studies. First, urban eddy covariance flux measurements were made from a building rooftop in Mexico City using a quadrupole aerosol mass spectrometer (Q-AMS) to determine the fluxes of aerosol species to/from the urban landscape. Second, conditional sampling of fine particles in updrafts and downdrafts was performed above a pine forest in Colorado using a thermal desorption chemical ionization mass spectrometer (TD-CIMS) to investigate the relative strengths of sources and sinks for speciated aerosol in a forest environment. Third, the aerosol and gas phase pollutant patterns, measured in Boise, ID during wintertime inversion conditions, were analyzed with respect to the daily evolution of the planetary boundary layer depth and surface meteorological conditions. This dissertation describes the methods used for each of the three studies and summarizes the analysis of the results.

  17. An advanced LC-MS (Q-TOF) technique for the detection of amino acids in atmospheric aerosols

    EPA Science Inventory

    Methodology for detection of native (underivitized) amino acids in atmospheric aerosols has been developed. This article describes the use of LC-MS (Q-TOF) and microwave-assisted gas phase hydrolysis for detection of free and combined amino acids in aerosols collected in a Southe...

  18. Analysis of Atmospheric Aerosol Data Sets and Application of Radiative Transfer Models to Compute Aerosol Effects

    NASA Technical Reports Server (NTRS)

    Schmid, Beat

    2005-01-01

    The Bay Area Environmental Research Institute (BAER) scientists have worked with the NASA Ames Research Center sunphotometer group led by Dr. Philip Russell for many years researching the climatic effects of aerosol particles in the stratosphere and troposphere. We have continued to work with the NASA Ames sunphotometer group in research activities representing funded, peer-reviewed proposals to NASA, NOAA and DOE. The activities are described in those proposals and also in the documents provided to the Grants Office earlier. This is the final report from January 1,2002 - June 30, 2005. The report consists of a compilation of 41 peer-reviewed publications (published, in press or submitted) produced under this Cooperative Agreement and 43 first-authored conference presentations. To save paper, reprints are not included but will, of course, be provided upon request.

  19. The System of the Calibration for Visibility Measurement Instrument Under the Atmospheric Aerosol Simulation Environment

    NASA Astrophysics Data System (ADS)

    Shu, Zhifeng; Yang, ShaoChen; Xu, Wenjing

    2016-06-01

    Visibility is one of the most important parameters for meteorological observation and numerical weather prediction (NWP).It is also an important factor in everyday life, mainly for surface and air traffic especially in the Aeronautical Meteorology. The visibility decides the taking off and landing of aircraft. If the airport visibility is lower than requirement for aircraft taking off stipulated by International Civil Aviation Administration, then the aircraft must be parked at the airport. So the accurate measurement of visibility is very important. Nowadays, many devices can be measured the visibility or meteorological optical range (MOR) such as Scatterometers, Transmissometers and visibility lidar. But there is not effective way to verify the accuracy of these devices expect the artificial visual method. We have developed a visibility testing system that can be calibration and verification these devices. The system consists of laser transmitter, optical chopper, phase-locking amplifier, the moving optic receiving system, signal detection and data acquisition system, atmospheric aerosol simulation chamber. All of them were placed in the atmosphere aerosol simulation chamber with uniform aerosol concentration. The Continuous wave laser, wavelength 550nm, has been transmitted into the collimation system then the laser beam expanded into 40mm diameter for compressing the laser divergence angle before modulated by optical chopper. The expanding beam transmitting in the atmosphere aerosol cabin received by the optic receiving system moving in the 50m length precision guide with 100mm optical aperture. The data of laser signal has been acquired by phase-locking amplifier every 5 meter range. So the 10 data points can be detected in the 50 meters guide once. The slope of the fitting curve can be obtained by linear fitting these data using the least square method. The laser extinction coefficient was calculated from the slope using the Koschmieder formula, then it been

  20. Quantifying the sources of atmospheric ice nuclei from carbonaceous combustion aerosol

    NASA Astrophysics Data System (ADS)

    Schill, G. P.; Jathar, S.; Galang, A.; Farmer, D.; Friedman, B.; Levin, E. J.; DeMott, P. J.; Kreidenweis, S. M.

    2015-12-01

    Ice nucleation on particles is a fundamental atmospheric process, which governs precipitation, cloud lifetimes, and climate. Despite being a basic atmospheric process, our current understanding of ice nucleation in the atmosphere is low. One reason for this low understanding is that ice nuclei concentrations are low (only ~1 in 105 particles in the free troposphere nucleate ice), making it challenging to identify both the composition and sources of ambient ice nuclei. Carbonaceous combustion aerosol produced from biomass and fossil fuel combustion are one potential source of these ice nuclei, as they contribute to over one-third of all aerosol in the North American free troposphere. Unfortunately, previous results from field measurements in-cloud, aircraft measurements, and laboratory studies are in conflict, with estimates of the impact of combustion aerosol ranging from no effect to rivaling the well-known atmospheric ice nuclei mineral dust. It is, however, becoming clear that aerosols from combustion processes are more complex than model particles, and their ice activity depends greatly on both fuel type and combustion conditions. Given these dependencies, we propose that sampling from real-world biomass burning and fossil fuel sources would provide the most useful new information on the contribution of carbonaceous combustion aerosols to atmospheric ice nuclei particles. To determine the specific contribution of refractory black carbon (rBC) to ice nuclei concentrations, we have coupled the Single Particle Soot Photometer (SP2) to the Colorado State University Continuous Flow Diffusion Chamber (CFDC). The SP2 utilizes laser-induced incandescence to quantify rBC mass on a particle-by-particle basis; in doing so, it also selectively destroys rBC particles by heating them to their vaporization temperature. Thus, the SP2 can be used as a selective pre-filter for rBC into the CFDC. In this work, we will present recent results looking at contribution of diesel

  1. A novel approach for the characterisation of transport and optical properties of aerosol particles near sources - Part II: Microphysics-chemistry-transport model development and application

    NASA Astrophysics Data System (ADS)

    Valdebenito B, Álvaro M.; Pal, Sandip; Behrendt, Andreas; Wulfmeyer, Volker; Lammel, Gerhard

    2011-06-01

    A new high-resolution microphysics-chemistry-transport model (LES-AOP) was developed and applied for the investigation of aerosol transformation and transport in the vicinity of a livestock facility in northern Germany (PLUS1 field campaign). The model is an extension of a Large-Eddy Simulation (LES) model. The PLUS1 field campaign included the first deployment of the new eye-safe scanning aerosol lidar system of the University of Hohenheim. In a combined approach, model and lidar results were used to characterise a faint aerosol source. The farm plume structure was investigated and the absolute value of its particle backscatter coefficient was determined. Aerosol optical properties were predicted on spatial and temporal resolutions below 100 m and 1 min, upon initialisation by measured meteorological and size-resolved particulate matter mass concentration and composition data. Faint aerosol plumes corresponding to a particle backscatter coefficient down to 10 -6 sr -1 m -1 were measured and realistically simulated. Budget-related quantities such as the emission flux and change of the particulate matter mass, were estimated from model results and ground measurements.

  2. Mixing state and spectral absorption of atmospheric aerosols observed at a marine background site

    NASA Astrophysics Data System (ADS)

    Cayetano, M. G.; Lee, K. Y.; Kim, Y. J.

    2011-12-01

    Mineral dust and sea salt particles are portions of atmospheric aerosols in Korea due to the periodic transport of loess dust particles from Gobi and Taklimakan deserts in west China, as well as the sea salt enrichment of atmospheric particles from the seas surrounding the Korean peninsula [Kim et al., 2009; Sahu et al., 2009]. Carbonaceous particles and secondary inorganic aerosols (sulphates and nitrates) are ubiquitous due to the proliferating biomass burning [Ryu et al., 2004], as well as the increasing use of fossil fuels locally and by regional transport from neighbouring countries. Collectively, when these aerosols are transported, their compositions are further modified due to the aging process, impacting their physico-chemical properties including spectral absorption. In order to investigate the spectral response of the absorption under different ambient aerosol conditions, measurements have been conducted at a marine background site in Korea (Deokjeok Island. 37° 13' 33" N, 126° 8' 51" E) during the spring (13 days) and fall (8 days) seasons of 2009 using an aethalometer (Magee AE31), a nephelometer (Optec NGN2a) and other supporting instruments (PILS-IC, PM2.5 cyclone samplers for off-line OC/EC measurements). It has been found that spring aerosols were dominated by sulphate-rich and carbonaceous-rich fractions (21.4%±8.0% and 28.8%±7.9%, respectively), with an Angström exponent of absorption, αabs = 1.3±0.1 at 370-950 nm. The fall season aerosols were grouped based on their chemical composition as acidic aerosols, dust-enriched, and seasalt-enriched aerosols. Angström exponent of absorption, αabs for acidic aerosols was obtained to be 1.3±0.2 at 370-950 nm. However, dust enriched aerosols showed increased absorption in the short UV-Vis range (370-590 nm), which can be attributed to their mixing with light absorbing aerosols. Different types of aerosols exhibit different spectral absorption characteristics depending on their composition and

  3. Characterisation of iron-rich atmospheric submicrometre particles in the roadside environment

    NASA Astrophysics Data System (ADS)

    Sanderson, P.; Su, S. S.; Chang, I. T. H.; Delgado Saborit, J. M.; Kepaptsoglou, D. M.; Weber, R. J. M.; Harrison, Roy M.

    2016-09-01

    Human exposure to ambient metallic nanoparticles is an area of great interest owing to their potential health impacts. Ambient metallic nanoparticles found in the roadside environment are contributed by combustion engines and wear of brakes, tyres and road surfaces. Submicrometre atmospheric particles collected at two UK urban sites have been subject to detailed characterisation. It is found that many metallic nanoparticles collected from roadside sampling sites are rich in iron. The Fe-rich nanoparticles can be classified into (1) high Fe content (ca 90 wt%) with each alloying element less than 1 wt%; and (2) moderate Fe content (<75 wt%) with high manganese and silicon content. Both clusters contain a variable mix of minor constituents, Mn, S and Si being most important in the high-Fe group. The moderate Fe group also contains Zn, Cu, Ba, Al and Ca. The Fe-rich nanoparticles exhibit primary particle sizes ranging between 20 and 30 nm, although some much larger particles up to around 100 nm can also be observed, along with some very small particles of 10 nm or less. These tend to agglomerate forming clusters ranging from ∼200 nm to 1 μm in diameter. The iron-rich particles observed are oxides, taking the form of spheres or multifaceted regular polyhedra. Analysis by EELS shows that both high- and moderate-Fe groups include particles of FeO, Fe3O4, α-Fe2O3 and γ-Fe2O3 of which γ-Fe2O3 is the most prominent. Internal mixing of different Fe-oxides is not observed.

  4. Radiosonde aerosol counter for vertical profiling of atmospheric dust layers

    NASA Astrophysics Data System (ADS)

    Ulanowski, Z.; Hirst, E.; Kaye, P. H.; Harrison, R. G.; Nicoll, K. A.; Rogers, G.

    2010-05-01

    A low-cost, miniature aerosol particle counter has been developed, intended for use with balloon-borne meteorological radiosondes. It is particularly suitable for airborne mineral dust measurements. Ambient air is drawn into the counter using a diaphragm pump at a rate of 0.5 litre per minute. The counter detects particles in the airstream using a diode laser and a photodiode. Output from the photodiode is digitised into 5 size bins, with minimum particle diameters equivalent to 0.6, 1.4, 2.6, 5.4 and 10.6 micrometers. The counter is interfaced to a Vaisala RS92 radiosonde, which transmits data from the counter together with meteorological parameters and GPS-derived position to a ground based receiver at 1 Hz rate. Statistically significant particle size distributions can be obtained once a second for number concentrations down to about 100,000 particle per litre (within the measured size range), or correspondingly less at lower temporal resolutions. At the same time, the counter is capable of measuring dust number concentrations exceeding a million per litre without incurring significant errors. Soundings during the DREAME campaign in Kuwait (Ulanowski et al. EGU 2010, AS4.7) and on Cape Verde Islands (Nicoll et al. EGU 2010, AS4.7) provided dust concentration profiles with a typical vertical resolution of 4 m. Comparisons with integrated dust column size distribution measurements from AERONET sun photometers showed good agreement in two out of three cases where near-simultaneous retrievals were available. Optical thickness calculations based on the size distributions measured in Kuwait, with the assumption that the dust particles were prolate spheroids, agreed with the AERONET optical thickness at 675 nm to within 15%.

  5. Scattering properties of the atmospheric aerosol in Beijing, China

    NASA Astrophysics Data System (ADS)

    Zhao, Xiujuan; Zhang, Xiaoling; Pu, Weiwei; Meng, Wei; Xu, Xiaofeng

    2011-08-01

    Measurements of aerosol scattering coefficient (σ sp) and PM 2.5 concentration obtained during June 2008 to May 2009 at urban, suburban, and rural sites in Beijing area. The mean value of σ sp during measurement period was 301 ± 307, 263 ± 263, 182 ± 201 Mm - 1 at Baolian (BL: urban site), Changping (CP: suburban site) and Shangdianzi (SDZ: rural site), respectively. The seasonal and diurnal patterns of σ sp were analyzed with the measurement data. The σ sp showed different seasonal and diurnal patterns at these three sites. The seasonal fluctuations inσ sp in urban area were mostly influenced by seasonal variability in both emissions and meteorological conditions, while the seasonal wind patterns seemed to dominate the σ sp in the suburban and rural areas. The diurnal activity of σ sp generally showed a bimodal, trimodal and a unimodal pattern at BL, CP and SDZ sites, respectively. The diurnal variation of boundary layer height companying with source activity was mainly dominated the diurnal variation of σ sp at urban and suburban sites. The mountain-valley breeze and boundary layer growth in SDZ region mostly dominated the diurnal variation of σ sp. The mass scattering efficiency of PM 2.5 was estimated at BL and SDZ, which showed a decreasing trend from urban to rural site with different seasonal variation at two sites. During fog and haze episodes, the lower northeasterly winds could result in significant spatial difference in σ sp, while the σ sp was spatially uniform under the influence of stronger southerly winds.

  6. PD-FiTE - an efficient method for calculating gas / liquid equilibria in atmospheric aerosol particles

    NASA Astrophysics Data System (ADS)

    Topping, D.; Lowe, D.; McFiggans, G.; Barley, M.

    2009-04-01

    Assessing the impact of atmospheric aerosol particles on the environment requires adequate representation of appropriate key processes within large scale models. In the absence of primary particulate material, interactions between the atmospheric gaseous components and particles means that the chemical nature of the particles is largely determined by the availability of condensable gaseous material, such as sulphuric and nitric acids, and by the ambient environmental conditions. Gas to particle mass transfer of semi-volatile components,driven by a difference in equilibrium and actual partial pressures above an aerosol particle, is an important factor in determining the evolving chemical composition of the particle and is necessary for predicting aerosol loading and composition. The design of an appropriate framework required for parameterizations of key variables is challenging. These thermodynamic frameworks are often numerically very complex, resulting in significant computational expense. Three dimensional chemical and aerosol transport models demand that computational expense be kept at a minimum,resulting in a trade-off between accuracy and efficiency. To calculate the equilibrium vapour pressure above a solution requires treatment of solution nonideality. This is manifest through activity coefficients of components pertinent to each condensing specie. However, activity coefficients are complex functions of the solution composition. Parameterisation of activity coefficients provides the main focus of this work largely because reducing the numerical complexity whilst retaining a good level of accuracy is very challenging. The approach presented here, the hybrid Partial Derivative Fitted Taylor Expansion (PDFiTE) (Topping et al 2008), builds on previously reported work, with an aim to derive parameters for an accurate and computationally efficient framework through coupling with a complex thermodynamic model. Such a reduction in complexity is important as it is

  7. An advanced technique for speciation of organic nitrogen in atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Samy, S.; Robinson, J.; Hays, M. D.

    2011-12-01

    The chemical composition of organic nitrogen (ON) in the environment is a research topic of broad significance. The topic intersects the branches of atmospheric, aquatic, and ecological science; thus, a variety of instrumentation, analytical methods, and data interpretation tools have evolved for determination of ON. Recent studies that focus on atmospheric particulate nitrogen (N) suggest a significant fraction (20-80%) of total N is bound in organic compounds. The sources, bioavailability and transport mechanisms of these N-containing compounds can differ, producing a variety of environmental consequences. Amino acids (AA) are a key class of atmospheric ON compounds that can contribute to secondary organic aerosol (SOA) formation and potentially influence water cycles, air pollutant scavenging, and the radiation balance. AA are water-soluble organic compounds (WSOC) that can significantly alter the acid-base chemistry of aerosols, and may explain the buffering capacity that impacts heterogeneous atmospheric chemistry. The chemical transformations that N-containing organic compounds (including AA) undergo can increase the light-absorbing capacity of atmospheric carbon via formation of 'brown carbon'. Suggested sources of atmospheric AA include: marine surface layer transport from bursting sea bubbles, the suspension of bacteria, fungi, algae, pollen, spores, or biomass burning. Methodology for detection of native (underivatized) amino acids (AA) in atmospheric aerosols has been developed and validated (Samy et al., 2011). This presentation describes the use of LC-MS (Q-TOF) and microwave-assisted gas phase hydrolysis for detection of free and combined amino acids in aerosols collected in a Southeastern U.S. forest environment. Accurate mass detection and the addition of isotopically labeled surrogates prior to sample preparation allows for sensitive quantitation of target AA in a complex aerosol matrix. A total of 16 native AA were detected above the reporting

  8. Monitoring of atmospheric aerosol emissions using a remotely piloted air vehicle (RPV)-Borne Sensor Suite

    SciTech Connect

    1996-05-01

    We have developed a small sensor system, the micro-atmospheric measurement system ({mu}-AMS), to monitor and track aerosol emissions. The system was developed to fly aboard a remotely piloted air vehicle, or other mobile platform, to provide real-time particle measurements in effluent plumes and to collect particles for chemical analysis. The {mu}-AMS instrument measures atmospheric parameters including particle mass concentration and size distribution, temperature, humidity, and airspeed, altitude and position (by GPS receiver) each second. The sensor data are stored onboard and are also down linked to a ground station in real time. The {mu}-AMS is battery powered, small (8 in. dia x 36 in.), and lightweight (15 pounds). Aerosol concentrations and size distributions from above ground explosive tests, airbone urban pollution, and traffic-produced particulates are presented.

  9. Non-linear photochemical pathways in laser-induced atmospheric aerosol formation

    PubMed Central

    Mongin, Denis; Slowik, Jay G.; Schubert, Elise; Brisset, Jean-Gabriel; Berti, Nicolas; Moret, Michel; Prévôt, André S. H.; Baltensperger, Urs; Kasparian, Jérôme; Wolf, Jean-Pierre

    2015-01-01

    We measured the chemical composition and the size distribution of aerosols generated by femtosecond-Terawatt laser pulses in the atmosphere using an aerosol mass spectrometer (AMS). We show that nitric acid condenses in the form of ammonium nitrate, and that oxidized volatile organics also contribute to particle growth. These two components account for two thirds and one third, respectively, of the dry laser-condensed mass. They appear in two different modes centred at 380 nm and 150 nm. The number concentration of particles between 25 and 300 nm increases by a factor of 15. Pre-existing water droplets strongly increase the oxidative properties of the laser-activated atmosphere, substantially enhancing the condensation of organics under laser illumination. PMID:26450172

  10. Organic Aerosol Volatility Parameterizations and Their Impact on Atmospheric Composition and Climate

    NASA Technical Reports Server (NTRS)

    Tsigaridis, Konsta; Bauer, Susanne E.

    2015-01-01

    Despite their importance and ubiquity in the atmosphere, organic aerosols are still very poorly parameterized in global models. This can be explained by two reasons: first, a very large number of unconstrained parameters are involved in accurate parameterizations, and second, a detailed description of semi-volatile organics is computationally very expensive. Even organic aerosol properties that are known to play a major role in the atmosphere, namely volatility and aging, are poorly resolved in global models, if at all. Studies with different models and different parameterizations have not been conclusive on whether the additional complexity improves model simulations, but the added diversity of the different host models used adds an unnecessary degree of variability in the evaluation of results that obscures solid conclusions.

  11. Methodological aspects of assessing atmospheric contamination with metal aerosols in the vicinity of thermal power complexes.

    PubMed

    Sokolov, S M

    1986-01-01

    A study of metal aerosols content in waste steam-containing gases from a thermal power station operating on oil fuel revealed that the concentrations of V2O5, Al2O3, Fe2O3, MnO2 and Cr2O3 are not influenced by the operational mode, type of boiler, the mean ratios being 1 : 0, 3 : 0, 27 : 0, 2 : 0, 03 : 0 and 0.25 respectively. Comparing the metal content in oil fuel and waste gases showed that no more than 10% of the studied compounds are sorbed on the boiler walls, the remaining 90% being released into the atmosphere. It is suggested that V2O5 be determined as an integral indicator with the aim of rapid hygienic assessment of the extent of atmospheric contamination with metal aerosols. The presented results may be used in preventive and regular sanitary surveillance during thermal power plant designing, construction and reconstruction.

  12. Compact Ozone Lidar for Atmospheric Ozone and Aerosol Measurements

    NASA Technical Reports Server (NTRS)

    Marcia, Joel; DeYoung, Russell J.

    2007-01-01

    A small compact ozone differential absorption lidar capable of being deployed on a small aircraft or unpiloted atmospheric vehicle (UAV) has been tested. The Ce:LiCAF tunable UV laser is pumped by a quadrupled Nd:YLF laser. Test results on the laser transmitter demonstrated 1.4 W in the IR and 240 mW in the green at 1000 Hz. The receiver consists of three photon-counting channels, which are a far field PMT, a near field UV PMT, and a green PMT. Each channel was tested for their saturation characteristics.

  13. Characterisation of atmospheric deposition as a source of contaminants in urban rainwater tanks.

    PubMed

    Huston, R; Chan, Y C; Gardner, T; Shaw, G; Chapman, H

    2009-04-01

    To characterise atmospheric input of chemical contaminants to urban rainwater tanks, bulk deposition (wet+dry deposition) was collected at sixteen sites in Brisbane, Queensland, Australia on a monthly basis during April 2007-March 2008 (N=175). Water from rainwater tanks (22 sites, 26 tanks) was also sampled concurrently. The deposition/tank water was analysed for metals, soluble anions and selected samples were additionally analysed for PAHs, pesticides, phenols, organic & inorganic carbon. Flux (mg/m(2)/d) of total solids mass was found to correlate with average daily rainfall (R(2)=0.49) indicating the dominance of the wet deposition contribution to total solids mass. On average 97% of the total mass of analysed components was accounted for by Cl(-) (25.0%), Na (22.6%), organic carbon (20.5%), NO(3)(-) (10.5%), SO(4)(2-) (9.8%), inorganic carbon (5.7%), PO(4)(3-) (1.6%) and NO(2)(-) (1.5%). For other minor elements the average flux from highest to lowest was in the order of Fe>Al>Zn>Mn>Sr>Pb>Ba>Cu>Se. There was a significant effect of location on flux of K, Sb, Sn, Li, Mn, Fe, Cu, Zn, Ba, Pb and SO(4)(2-) but not other metals or anions. Overall the water quality resulting from the deposition (wet+dry) was good but 10.3%, 1.7% and 17.7% of samples had concentrations of Pb, Cd and Fe respectively greater than the Australian Drinking Water Guidelines (ADWG). This generally occurred in the drier months. In comparison 14.2% and 6.1% of tank samples had total Pb and Zn concentrations exceeding the guidelines. The cumulative mean concentration of lead in deposition was on average only 1/4 of that in tank water over the year at a site with high concentrations of Pb in tank water. This is an indication that deposition from the atmosphere is not the major contributor to high lead concentrations in urban rainwater tanks in a city with reasonable air quality, though it is still a significant portion.

  14. Aerosol contributions to speleothem geochemistry

    NASA Astrophysics Data System (ADS)

    Dredge, J. A.; Fairchild, I. J.; Harrison, R.; Woodhead, J. D.; Hellstrom, J.

    2011-12-01

    The term "aerosols" encompasses the suspension of both fine solid or liquid particles within a gaseous medium. Aerosols become suspended into the earth's atmosphere through a multitude of processes both natural and anthropogenic. Atmospheric aerosols enter cave networks as a result of cave ventilation processes and are either deposited, or cycled and removed from the system. Speleothem offer a multiproxy palaeoclimate resource; many of the available proxies have been extensively investigated and utilised for palaeoclimatic reconstructions in a range of studies. The potential contribution of aerosols to speleothem chemistry and their applicability for palaeoenvironmental reconstructions remains untested and the extent of their value as an addition to palaeoclimate sciences unknown. Aerosols through incorporation into speleothem may provide a novel palaeoenvironmental resource. The aerosol component of interest is that which is transported into the cave atmosphere and deposited and are available for incorporation into precipitated calcite. Aerosol deposition and therefore distribution in the cave has shown to be a complex function of ventilation and changing environmental factors. Through detailed monitoring aerosols have been detected, identified, characterised and quantified to determine their prominence in the cave system. Investigations are on a case study basis, searching for suitable aerosol proxies of environmentally significant emission processes. Case studies include: Palaeofires at Yarrangobilly Caves, Australia; anthropogenic emissions at St Michaels Cave, Gibraltar and Cheddar gorge, UK; and drip water aerosol production and geochemical addition in Obir cave, Austria. Monitoring has allowed for the temporal and spatial determination of aerosols in karst networks. Speleothem samples will be analysed in combination with in-situ monitoring to determine incorporation factors and record preservation. By understanding how aerosols are transmitted within the

  15. Chemical and aerosol characterisation of the troposphere over West Africa during the monsoon period as part of AMMA

    NASA Astrophysics Data System (ADS)

    Reeves, C. E.; Formenti, P.; Afif, C.; Ancellet, G.; Attie, J.-L.; Bechara, J.; Borbon, A.; Cairo, F.; Coe, H.; Crumeyrolle, S.; Fierli, F.; Flamant, C.; Gomes, L.; Hamburger, T.; Lambert, C.; Law, K. S.; Mari, C.; Matsuki, A.; Methven, J.; Mills, G. P.; Minikin, A.; Murphy, J. G.; Nielsen, J. K.; Oram, D. E.; Parker, D. J.; Richter, A.; Schlager, H.; Schwarzenboeck, A.; Thouret, V.

    2010-03-01

    During June, July and August 2006 five aircraft took part in a campaign over West Africa to observe the aerosol content and chemical composition of the troposphere and lower stratosphere as part of the African Monsoon Multidisciplinary Analysis (AMMA) project. These are the first such measurements in this region during the monsoon period. In addition to providing an overview of the tropospheric composition, this paper provides a description of the measurement strategy (flights performed, instrumental payloads, wing-tip to wing-tip comparisons) and points to some of the important findings discussed in more detailed in other papers in this special issue. The ozone data exhibits an "S" shaped vertical profile which appears to result from significant losses in the lower troposphere due to rapid deposition to forested areas and photochemical destruction in the moist monsoon air, and convective uplift of O3-poor air to the upper troposphere. This profile is disturbed, particularly in the south of the region, by the intrusions in the lower and middle troposphere of air from the Southern Hemisphere impacted by biomass burning. Comparisons with longer term data sets suggest the impact of these intrusions on West Africa in 2006 was greater than in other recent wet seasons. There is evidence for net photochemical production of ozone in these biomass burning plumes as well as in urban plumes, in particular that from Lagos, convective outflow in the upper troposphere and in boundary layer air affected by nitrogen oxide emissions from recently wetted soils. This latter effect, along with enhanced deposition to the forested areas, contributes to a latitudinal gradient of ozone in the lower troposphere. Biogenic volatile organic compounds are also important in defining the composition both for the boundary layer and upper tropospheric convective outflow. Mineral dust was found to be the most abundant and ubiquitous aerosol type in the atmosphere over Western Africa. Data collected

  16. MODELING THE EFFECT OF CHLORINE EMISSIONS ON ATMOSPHERIC OZONE AND SECONDARY ORGANIC AEROSOL CONCENTRATIONS ACROSS THE UNITED STATES

    EPA Science Inventory

    This paper presents the modeled effects of natural and anthropogenic chlorine emissions on the atmospheric concentrations of ozone and secondary organic aerosol across the United States. The model calculations include anthropogenic molecular chlorine emissions, anthropogenic hypo...

  17. Modeling Greenland's Climate Response to the Presence of Biomass Burning Aerosols in the Atmosphere and Snow

    NASA Astrophysics Data System (ADS)

    Ward, J. L.; Flanner, M.; Bergin, M. H.; Courville, Z.; Dibb, J. E.; Polashenski, C.; Soja, A. J.; Strellis, B. M.

    2015-12-01

    Biomass burning events are known to produce large emissions of aerosol particles, including light-absorbing black carbon (BC) and brown carbon. Once exported from fire-based source regions to the Arctic via atmospheric transport mechanisms, these particles can change the regional climate through solar absorption while suspended at various heights in the atmosphere or once deposited onto the terrain (through the reduction of surface albedo). Greenland is particularly vulnerable to positive aerosol forcing due to its perennial ice cover and high surface albedo. Surface measurements and remote sensing observations indicate that Greenland is occasionally impacted by smoke from North American and Eurasian wildfires, including during the summer of 2011 when aerosol optical depth (AOD) over central Greenland exceeded 0.20 and aerosol single scattering albedo (SSA) dropped below 0.90. Measurements of impurities in snow pits also indicate that wildfires exerted transient influence on surface albedo during the summers of 2012 and 2013, with average peak BC concentrations of 4 and 15 ng/g, respectively. Here, we apply idealized climate simulations to study how Greenland surface temperature and melt are affected by elevated levels of light-absorbing particles above and on the ice sheet. We apply the Community Earth System Model (CESM) in a configuration with prescribed sea surface temperatures and active atmosphere and land model components. In one set of experiments, we prescribe constant values of AOD and SSA in the troposphere over Greenland, informed by measurements from 2011. In a second set of experiments we prescribe constant mass mixing ratios of BC and dust in surface snow based on measurements of snow that fell during 2012-2014. These simulations will inform on the amount of excess snow melt that may occur on Greenland due to biomass burning, and on the relative impacts of atmospheric and snow-deposited smoke.

  18. Effects of Coastal Topography and Atmospheric Aerosol on the Surface Forcing of Marginal Seas

    DTIC Science & Technology

    2003-09-30

    initial and lateral boundary conditions for the regional models (MM5 and Navy COAMPS ) in AMSG. WORK COMPLETED During the past year (FY2002...2003), we have developed modeling capability of including the dust and other atmospheric aerosols and investigating their impact on the radiative heat...total heat flux of the marginal seas, especially in the AMSG region is the contribution of the dust to the shortwave radiative flux. Fig. 1 shows an

  19. Aerosol Observability and Data Assimilation Investigations in Support of Atmospheric Composition Forecasts

    DTIC Science & Technology

    2012-09-30

    aerosol model demands for such applications as joint surface-atmosphere retrievals, directed energy (DE), and intelligence, surveillance, and...C. Schmidt, J. I Miettinen, L. Giglio, (2012), Different views of fire activity over Indonesia and Malaysia from polar and geostationary...Greece, 25-29 June, 2012. Hyer, E. J., J. S. Reid, E. M. Prins, J. Hoffman, C. C. Schmidt, L. Giglio, D. A. Peterson (2011) Biomass burning observations

  20. Arsenic speciation in atmospheric aerosols at The Geysers

    SciTech Connect

    Solomon, P.A.; Altshuler, S.L.; Keller, M.L. )

    1993-05-01

    California's air toxic law (AB 1807), which became effective in January 1984, defines California's air toxic program. Under this legislation, a statutory mandate was created for the identification and control of toxic air contaminants found in California. The California Air Resources Board (ARB) lists inorganic arsenic under Category I: substances that have been identified as toxic air contaminants by the ARB, pursuant to the provisions of AB1807. The enactment of new regulations regarding air toxics and ARB's report entitled [open quotes]Public Exposure to Airborne Inorganic Arsenic in California[close quotes] suggest that geothermal energy producers in California must remain aware of the current atmospheric levels of arsenic at The Geyser. These producers must also be able to provide evidence of the species-specific nature of the airborne arsenic if the regulatory climate changes to include the inorganic species of arsenic in health risk assessment calculations. Preliminary results reported by this paper are useful as a baseline to provide an indication of As(III) and As(V) concentration levels at The Geysers. If species-specific instead of total data on arsenic in the atmosphere are required by regulators, these results could be useful in evaluating future monitoring and assessment needs for arsenic at The Geysers. 12 refs., 1 fig., 1 tab.

  1. Simple aerosol correction technique based on the spectral relationships of the aerosol multiple-scattering reflectances for atmospheric correction over the oceans.

    PubMed

    Ahn, Jae-Hyun; Park, Young-Je; Kim, Wonkook; Lee, Boram

    2016-12-26

    An estimation of the aerosol multiple-scattering reflectance is an important part of the atmospheric correction procedure in satellite ocean color data processing. Most commonly, the utilization of two near-infrared (NIR) bands to estimate the aerosol optical properties has been adopted for the estimation of the effects of aerosols. Previously, the operational Geostationary Color Ocean Imager (GOCI) atmospheric correction scheme relies on a single-scattering reflectance ratio (SSE), which was developed for the processing of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data to determine the appropriate aerosol models and their aerosol optical thicknesses. The scheme computes reflectance contributions (weighting factor) of candidate aerosol models in a single scattering domain then spectrally extrapolates the single-scattering aerosol reflectance from NIR to visible (VIS) bands using the SSE. However, it directly applies the weight value to all wavelengths in a multiple-scattering domain although the multiple-scattering aerosol reflectance has a non-linear relationship with the single-scattering reflectance and inter-band relationship of multiple scattering aerosol reflectances is non-linear. To avoid these issues, we propose an alternative scheme for estimating the aerosol reflectance that uses the spectral relationships in the aerosol multiple-scattering reflectance between different wavelengths (called SRAMS). The process directly calculates the multiple-scattering reflectance contributions in NIR with no residual errors for selected aerosol models. Then it spectrally extrapolates the reflectance contribution from NIR to visible bands for each selected model using the SRAMS. To assess the performance of the algorithm regarding the errors in the water reflectance at the surface or remote-sensing reflectance retrieval, we compared the SRAMS atmospheric correction results with the SSE atmospheric correction using both simulations and in situ match-ups with the

  2. Formation mechanisms of water-soluble organic compounds in atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Huang, Xiaofeng

    Water-soluble organic compounds (WSOCs) are abundant in atmospheric aerosols, typically accounting for 20˜80% of particulate organic matter mass. Due to their affinity for water, WSOCs play an active role in aerosol-water interaction, and thus influence hygroscopic properties of aerosols, which in turn affect cloud formation processes and earth's radiation balance. Despite their abundance and significance, the sources of WSOCs are not well understood. Some primary sources (e.g., biomass burning) are known to emit WSOCs. It is also known from smog chamber experiments that photochemical oxidation of volatile organic compounds lead to less volatile oxygenated compounds that reside in the aerosol phase and are water-soluble because of the presence of polar functional groups. More recent work points to in-cloud/fog processes as a potentially important source for WSOCs. Work in this thesis aims to improve our understanding of the sources and formation mechanisms of WSOCs in atmospheric aerosols. Multiple approaches have been taken, including field measurements and controlled laboratory experiments. The thesis consists of the following four parts: (1) The formation mechanism of the most abundant WSOC species, oxalate, was investigated by synthesizing field measurement data obtained by our group and those available in the literature. Our measurements of aerosol sulfate and oxalate across a wide geographical span in the East Asia region, up to Beijing in the north and down to Hong Kong in the south, indicated that the two species were highly correlated. This good correlation was also found in measurements made elsewhere in the world by other researchers. Through a detailed analysis of factors influencing ambient oxalate, it can be argued that a common dominant formation pathway, likely in-cloud processing, explains the close tracking of the two chemically distinct species. This result also highlights the potential importance of in-cloud processing as a pathway leading to

  3. Sensitivity of Boreal-Summer Circulation and Precipitation to Atmospheric Aerosols in Selected Regions. Part 2; The Americas

    NASA Technical Reports Server (NTRS)

    Wilcox, E. M.; Sud, Y. C.; Walker, G.

    2009-01-01

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

  4. The Effect of Particle Size on Iron Solubility in Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Marcotte, A. R.; Majestic, B. J.; Anbar, A. D.; Herckes, P.

    2012-12-01

    The long range transport of mineral dust aerosols, which contain approximately 3% iron by mass, results in an estimated 14-16 Tg of iron deposited into the oceans annually; however, only a small percentage of the deposited iron is soluble. In high-nutrient, low chlorophyll ocean regions iron solubility may limit phytoplankton primary productivity. Although the atmospheric transport processes of mineral dust aerosols have been well studied, the role of particle size has been given little attention. In this work, the effect of particle size on iron solubility in atmospheric aerosols is examined. Iron-containing minerals (illite, kaolinite, magnetite, goethite, red hematite, black hematite, and quartz) were separated into five size fractions (10-2.5, 2.5-1, 1-0.5, 0.5-0.25, and <0.25μm) and extracted into buffer solutions simulating environments in the transport of aerosol particles for 150 minutes. Particle size was confirmed by scanning electron microscopy (SEM). Soluble iron content of the extracted mineral solutions was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Extracted mineral solutions were also analyzed for Fe(II) and Fe(III) content using a ferrozine/UV-VIS method. Preliminary results show that differences in solution composition are more important than differences in size. When extracted into acetate and cloudwater buffers (pH 4.25-4.3), < 0.3% of the Fe in iron oxides (hematite, magnetite, and goethite) is transferred to solution as compared to ~0.1-35% for clays (kaolinite and illite). When extracted into a marine aerosol solution (pH 1.7), the percentage of Fe of the iron oxides and clays transferred to solution increases to approximately 0.5-3% and 5-70%, respectively. However, there is a trend of increased %Fe in the minerals transferred to solution in the largest and smallest size fractions (~0.01-0.3% and ~0.5-35% for iron oxides and clays, respectively), and decreased %Fe in the minerals transferred to solution in the mid

  5. New planetary atmosphere simulations: application to the organic aerosols of Titan.

    PubMed

    Coll, P; Cosia, D; Gazeau, M C; Raulin, F

    1997-01-01

    The atmosphere of Titan partly consists of hazes and aerosol particles. Experimental simulation is one of the powerful approaches to study the processes which yield these particles, and their chemical composition. It provides laboratory analogues, sometimes called tholins. Development and optimization of experimental tools were undertaken in order to perform chemical and physical analyses of analogues under conditions free from contamination. A "Titan aerosol generator" was developed in the frame of the Cassini-Huygens mission, in order to produce Titan's aerosol analogues within conditions closer to those of the titanian atmosphere: cold plasma simulation system, low pressure and low temperature. The direct current (DC) glow discharge is produced by applying a DC voltage between two conductive electrodes inserted into the gas mixture-model of the studied atmosphere- at low pressure. A high-impedance power supply is used to provide the electrical field. All the system is installed in a glove box, which protect samples from any contamination. Finally the research program expected with this new material is presented.

  6. Experimental and theoretical investigation of nucleation and growth of atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Zhao, Jun

    Aerosol particles have profound impacts on human health, atmospheric radiation, and cloud microphysics and these impacts are strongly dependent on particle sizes. However, formation and growth of atmospheric particles are currently not well understood. In this work, laboratory and theoretical studies have been performed to investigate the formation and growth of atmospheric particles. The first two parts of the dissertation are a laboratory investigation of new particle formation and growth, and a theoretical study of atmospheric molecular complexes and clusters. The nucleation rate was considerably enhanced in the presence of cis-pinonic acid and ammonia. The composition of the critical cluster was estimated from the dependence of the nucleation rate on the precursor concentration and the time evolution of the clusters was then simulated using molecular dynamic simulations. Results from quantum chemical calculations and quantum theory of atoms in molecules (QTAIM) reveal that formation of strong hydrogen bonding between an organic acid and sulfuric acid is likely responsible for a reduction of the nucleation barrier by modifying the hydrophobic properties of the organic acid and allowing further addition of hydrophilic species (e.g., H2SO4, H2O, and possibly NH 3) to the hydrophilic side of the clusters. This promotes growth of the nascent cluster to overcome the nucleation barrier and thus enhances the nucleation in the atmosphere. The last part of this dissertation is the laboratory investigation of heterogeneous interactions of atmospheric carbonyls with sulfuric acid. Direct measurement has been performed to investigate the heterogeneous uptake of atmospheric carbonyls on sulfuric acid. Important parameters have been obtained from the time-dependent or time-independent uptake profiles. The results indicated that the acid-catalyzed reactions of larger aldehydes (e.g. octanal and 2, 4-hexadienal) in sulfuric acid solution were attributed to aldol condensation in

  7. Spatial and temporal correlation length as a measure for the stationarity of atmospheric dust aerosol distribution

    NASA Astrophysics Data System (ADS)

    Schepanski, Kerstin; Klüser, Lars; Heinold, Bernd; Tegen, Ina

    2015-12-01

    Fields of dust aerosol optical depth (AOD) from numerical models and satellite observations are widely used data sets for evaluating the actual distribution of atmospheric dust aerosol. In this study we investigate the use of estimates of spatial and temporal correlation lengths (CLs) calculated from simulations using the regional model system COSMO-MUSCAT (COSMO: Consortium for Small-scale Modelling; MUSCAT: MUltiScale Chemistry Aerosol Transport Model) to characterize the spatial and temporal variability of atmospheric aerosol distribution, here mineral dust, and to provide an estimate on the temporal model output interval required in order to represent the local evolution of atmospheric dustiness. The CLs indicate the scales of variability for dust and thus provide an estimate for the stationarity of dust conditions in space and time. Additionally, CLs can be an estimate for the required resolution in time and space of observational systems to observe changes in atmospheric dust conditions that would be relevant for dust forecasts. Here, two years of dust simulations using COSMO-MUSCAT are analyzed. CLs for the individual years 2007 and 2008 are compared to the entire two-year period illustrating the impact of the length of time series on statistical analysis. The two years are chosen as they are contrasting with regard to mineral dust loads and thus provide additional information on the representativeness of the statistical analysis. Results from the COSMO-MUSCAT CL analysis are compared against CL estimates from satellite observations, here dust AOD inferred from IASI (Infrared Atmospheric Sounding Interferometer), which provides bi-daily information of atmospheric dust loading over desert land and ocean. Although CLs estimated from the satellite observations are at a generally lower level of values, the results demonstrate the applicability of daily observations for assessing the atmospheric dust distribution. Main outcomes of this study illustrate the

  8. Heterogeneous chemistry of HOBR on surfaces characteristic of atmospheric aerosols

    SciTech Connect

    Abbatt, J.P.D.

    1995-12-31

    The heterogeneous interactions of HOBr, HBr and HCl with ice and supercooled sulfuric acid solutions have been studied in a low temperatures low pressure flow tube coupled to a mass spectrometer. The heterogeneous reactions HOBr + HCl {yields} BrCl + H{sub 2}O and HOBr + HBr {yields} Br{sub 2} + H{sub 2}O have been demonstrated to proceed readily on these surfaces, and it has been shown that both HOBr and HBr are more easily partitioned to the condensed phase than their chlorine analogues. These heterogeneous reactions represent routes for the activation of halogen species in the atmosphere. In particular, the implications of this research to the depletion of stratospheric ozone after the Mt. Pinatubo volcanic eruption and to the depletion of ozone in the springtime Arctic boundary layer will be discussed.

  9. An automated baseline correction protocol for infrared spectra of atmospheric aerosols collected on polytetrafluoroethylene (Teflon) filters

    NASA Astrophysics Data System (ADS)

    Kuzmiakova, Adele; Dillner, Ann M.; Takahama, Satoshi

    2016-06-01

    A growing body of research on statistical applications for characterization of atmospheric aerosol Fourier transform infrared (FT-IR) samples collected on polytetrafluoroethylene (PTFE) filters (e.g., Russell et al., 2011; Ruthenburg et al., 2014) and a rising interest in analyzing FT-IR samples collected by air quality monitoring networks call for an automated PTFE baseline correction solution. The existing polynomial technique (Takahama et al., 2013) is not scalable to a project with a large number of aerosol samples because it contains many parameters and requires expert intervention. Therefore, the question of how to develop an automated method for baseline correcting hundreds to thousands of ambient aerosol spectra given the variability in both environmental mixture composition and PTFE baselines remains. This study approaches the question by detailing the statistical protocol, which allows for the precise definition of analyte and background subregions, applies nonparametric smoothing splines to reproduce sample-specific PTFE variations, and integrates performance metrics from atmospheric aerosol and blank samples alike in the smoothing parameter selection. Referencing 794 atmospheric aerosol samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011, we start by identifying key FT-IR signal characteristics, such as non-negative absorbance or analyte segment transformation, to capture sample-specific transitions between background and analyte. While referring to qualitative properties of PTFE background, the goal of smoothing splines interpolation is to learn the baseline structure in the background region to predict the baseline structure in the analyte region. We then validate the model by comparing smoothing splines baseline-corrected spectra with uncorrected and polynomial baseline (PB)-corrected equivalents via three statistical applications: (1) clustering analysis, (2) functional group quantification

  10. Impact of wet scavenging of natural and anthropogenic aerosol components on the columnar aerosol optical depth over a tropical rural atmosphere

    NASA Astrophysics Data System (ADS)

    Chatterjee, Abhijit; Jayaraman, Achuthan

    A typical feature of Indian monsoon is that, several dry days are observed even between the rain events. Atmospheric aerosol shows significant variations in their concentration between "before" and "after" the rain because of their efficient scavenging during the rain. The below cloud scavenging of several aerosol components during the rain has a direct impact on the columnar aerosol optical depth (AOD) between "before" and "after" the rain. In order to investigate the impact of the scavenging of several natural and anthropogenic aerosol components on spectral properties of aerosol, simultaneous studies on the characterization of aerosol, rainwater and AOD were done during July-December 2009 over a tropical rural atmosphere at Gadanki (13.5 0N, 79.2 0E) in southern peninsular India. Aerosols were collected and analyzed before, during and after the rain along with the collection and analysis of rainwater in several rain events during the entire study period. AOD data (at wavelengths of 400, 500, 675, 870, 1020 nm) was retrieved by processing the data obtained from an automatic sunphotomer (PREDE, PM 01) using the standard SKYRAD pack. Aerosols and rainwater samples were analyzed for water soluble ionic species using an Ion Chromatograph (Metrohm, 861). We observed that aerosols were highly loaded in the atmosphere just before the rain, efficiently scavenged during the rain and built-up slowly after the rain. Interestingly, the loading of sulphate aerosol after the rain was remarkably high whereas that of calcium and magnesium were remarkably low. The poor resuspension of soil dust from the wet soils after the rain could not allow calcium and magnesium to be loaded in the atmosphere whereas the high relative humidity favored the gas-to-particle conversion of SO2 to SO42-which allowed the high loading of sulphate aerosol in the atmosphere. Significant reductions in AOD both at lower (400 nm) and higher wavelength (1020 nm) were observed after the rain events. Two

  11. The impact of residential combustion emissions on atmospheric aerosol, human health and climate

    NASA Astrophysics Data System (ADS)

    Butt, E. W.; Rap, A.; Schmidt, A.; Reddington, C.; Scott, C.; Pringle, K.; Woodhouse, M.; Spracklen, D. V.

    2015-12-01

    Combustion of fuels in the residential sector for cooking and heating, results in the emission of aerosol and aerosol precursors that effect air quality, human health and climate. Residential emissions are dominated by the combustion of solid fuels which are the primary energy source for nearly half the world's population. Despite this importance, residential emissions are poorly quantified, as are their impacts on air quality and climate. We used a global aerosol microphysics model to simulate the impact of residential emissions on atmospheric aerosol in the year 2000, and evaluated simulated concentrations against surface observations of aerosol mass and number. Residential emissions make the largest contributions to surface particulate matter (PM2.5) concentrations in East Asia, South Asia and Eastern Europe, matching regions of greatest emissions. We used concentration response functions to estimate a global annual excess adult (> 30 years of age) premature mortality due to residential emissions of between 113, 300 and 827, 000 when uncertainties in both residential emissions and health effects of PM2.5 were accounted for. Premature mortality was greatest in Asia, with China and India accounting for 50% of simulated global excess mortality. Using an offline radiative transfer model, we show that residential emissions exerted a global annual mean direct radiative effect of between -66 mW m-2 and +21 mW m-2, accounting for uncertainties in emissions flux and assumed ratio of carbonaceous and sulphur emissions. Residential emissions exerted a negative global annual mean first aerosol indirect effect of between -52 mW m-2 and -16 mW m-2, which was found to be sensitive to the assumed size distribution of carbonaceous emissions. Our results demonstrate that reducing residential combustion emissions would have substantial benefits for human health through reductions in ambient PM2.5 concentrations.

  12. Aerosol variability and atmospheric transport in the Himalayan region from CALIOP 2007-2010 observations

    NASA Astrophysics Data System (ADS)

    Bucci, S.; Cagnazzo, C.; Cairo, F.; Di Liberto, L.; Fierli, F.

    2013-06-01

    Himalayan Plateau is surrounded by regions with high natural and anthropogenic aerosol emissions that have a strong impact on regional climate. This is particularly critical for the Himalayan glaciers whose equilibrium is also largely influenced by radiative direct and indirect effects induced by aerosol burden. This work focuses on the spatial and vertical distribution of different aerosol types, their seasonal variability and sources. The analysis of the 2007-2010 yr of CALIPSO vertically resolved satellite data allows the identification of spatial patterns of desert dust and carbonaceous particles in different atmospheric layers. Clusters of Lagrangian back-trajectories highlight the transport pathways from source regions during the dusty spring season. The analysis shows a prevalence of dust; at low heights they are distributed mainly north (with a main contribution from the Gobi and Taklamakan deserts) and west of the Tibetan Plateau (originating from the deserts of South-West Asia and advected by the westerlies). Above the Himalayas the dust amount is minor but still not negligible (detectable in around 20% of the measurements), and transport from more distant deserts (Sahara and Arabian Peninsula) is important. Smoke aerosol, produced mainly in North India and East China, is subject to shorter range transport and is indeed observed closer to the sources while there is a limited amount reaching the top of the plateau. Data analysis reveals a clear seasonal variability in the frequencies of occurrence for the main aerosol types; dust is regulated principally by the monsoon dynamics, with maxima of occurrence in spring. The study also highlights relevant interannual differences, showing a larger presence of aerosol in the region during 2007 and 2008 yr.

  13. Atmospheric aerosol scavenging processes and the role of thermo- and diffusio-phoretic forces

    NASA Astrophysics Data System (ADS)

    Santachiara, Gianni; Prodi, Franco; Belosi, Franco

    2013-07-01

    In-cloud and below-cloud scavenging due to snow crystals is reviewed, outlining the theoretical models, laboratory and field measurements which take into account also the role of phoretic forces in this process. In-cloud scavenging includes contributions from both nucleation and impaction, while below-cloud scavenging includes only impaction. Scavenging of aerosol particles by ice has been modelled only for simple shapes (planar and columnar ice crystals) and restricted size range, in view of the large variety of shapes and, consequently, the complicated flow patterns of air, water vapour and heat around the crystal. A significant feature of theoretical efficiency curves is the predominant minimum for aerosol particles of radius between 0.01 and 0.1 μm where phoretic forces are active, analogous to the particle scavenging behaviour of water drops. Experiments on aerosol particle scavenging by snow include field measurements, experiments where natural snow crystals are allowed to fall through laboratory generated aerosol, and experiments where both crystals and aerosol are generated in the laboratory. Contradictory results have been found in laboratory and field experiments concerning the role of phoretic forces. In particular, an important discrepancy arises relating to the roles of thermophoresis and diffusiophoresis in the scavenging of submicron particles by ice crystals growing in mixed-phase clouds, consisting of water vapour, supercooled liquid droplets and ice particles. A decrease in scavenging efficiency as a function of crystal diameter is reported both theoretically and experimentally. By comparing aerosol scavenging by drops and snow, most studies agree that, in terms of equal mass of precipitation, snow is more efficient at scavenging atmospheric particles than rain.

  14. Understanding aerosol formation mechanisms in a subtropical atmosphere impacted by biomass burning and agroindustry

    NASA Astrophysics Data System (ADS)

    Souza, Michele L.; Allen, Andrew G.; Cardoso, Arnaldo A.

    2017-01-01

    This work provides evidence for the existence of strong seasonality in homogeneous and heterogeneous aerosol formation in a subtropical region affected by agricultural biomass burning. Acquisitions of aerosol size distributions were made in central São Paulo State between August 2011 and November 2012, using a scanning mobility particle sizer (SMPS) system. Aerosols were also collected using a high volume impactor for analysis of major ions in the < 0.49 μm size fraction. The SMPS data were grouped into three size fractions: < 25 nm, 25-100 nm, and 100-615 nm, which were used to represent the nucleation, Aitken, and lower accumulation mode size ranges, respectively. Different aerosol types and atmospheric conditions were shown to influence the relative contributions of the different aerosol size fractions and their interrelationships. The total number concentrations of particles in the nucleation size range varied between 4.03 × 10- 3 and 5.18 × 104 cm- 3, concentrations in the Aitken size range varied between 1.60 × 101 and 3.17 × 104 cm- 3, and concentrations in the accumulation size range varied between 0.00 and 6.67 × 103 cm- 3. Distinct seasonal differences in particle formation were observed, with evidence for the preferential occurrence of homogeneous nucleation during the wetter summer months and heterogeneous nucleation during the winter when there were strong emissions from biomass burning. Homogeneous nucleation of new particles was inhibited in the winter, due to the greater surface area of existing aerosols available for the uptake of reactive gases. Consequently, the nucleation and Aitken modes were favored in the wet (summer) and dry (winter biomass burning) periods, respectively. The accumulation mode showed peaks in the summer and winter, which could be explained by hygroscopic particle growth and heterogeneous reactions, respectively.

  15. Climatological simulations of ozone and atmospheric aerosols in the Greater Cairo region

    SciTech Connect

    Steiner, A. L.; Tawfik, A. B.; Shalaby, A.; Zakey, A. S.; Abdel Wahab, M. M.; Salah, Z.; Solmon, F.; Sillman, S.; Zaveri, Rahul A.

    2014-04-16

    An integrated chemistry-climate model (RegCM4-CHEM) simulates present-day climate, ozone and tropospheric aerosols over Egypt with a focus on Greater Cairo (GC) region. The densley populated GC region is known for its severe air quality issues driven by high levels of anthropogenic pollution in conjuction with natural sources such as dust and agricultural burning events. We find that current global emission inventories underestimate key pollutants such as nitrogen oxides and anthropogenic aerosol species. In the GC region, average-ground-based NO2 observations of 40-60 ppb are substantially higher than modeled estimates (5-10 ppb), likely due to model grid resolution, improper boundary layer representation, and poor emissions inventories. Observed ozone concentrations range from 35 ppb (winter) to 80 ppb (summer). The model reproduces the seasonal cycle fairly well, but modeled summer ozone is understimated by approximately 15 ppb and exhibits little interannual variability. For aerosols, springtime dust events dominate the seasonal aerosol cycle. The chemistry-climate model captures the springtime peak aerosol optical depth (AOD) of 0.7-1 but is slightly greater than satellite-derived AOD. Observed AOD decreases in the summer and increases again in the fall due to agricultural burning events in the Nile Delta, yet the model underestimates this fall observed AOD peak, as standard emissions inventories underestimate this burning and the resulting aerosol emissions. Our comparison of modeled gas and particulate phase atmospheric chemistry in the GC region indicates that improved emissions inventories of mobile sources and other anthropogenic activities are needed to improve air quality simulations in this region.

  16. How much does sea spray aerosol organic matter impact clouds and radiation? Sensitivity studies in the Community Atmosphere Model

    NASA Astrophysics Data System (ADS)

    Burrows, S. M.; Liu, X.; Elliott, S.; Easter, R. C.; Singh, B.; Rasch, P. J.

    2015-12-01

    Submicron marine aerosol particles are frequently observed to contain substantial fractions of organic material, hypothesized to enter the atmosphere as part of the primary sea spray aerosol formed through bubble bursting. This organic matter in sea spray aerosol may affect cloud condensation nuclei and ice nuclei concentrations in the atmosphere, particularly in remote marine regions. Members of our team have developed a new, mechanistic representation of the enrichment of sea spray aerosol with organic matter, the OCEANFILMS parameterization (Burrows et al., 2014). This new representation uses fields from an ocean biogeochemistry model to predict properties of the emitted aerosol. We have recently implemented the OCEANFILMS representation of sea spray aerosol composition into the Community Atmosphere Model (CAM), and performed sensitivity experiments and comparisons with alternate formulations. Early results from these sensitivity simulations will be shown, including impacts on aerosols, clouds, and radiation. References: Burrows, S. M., Ogunro, O., Frossard, A. A., Russell, L. M., Rasch, P. J., and Elliott, S. M.: A physically based framework for modeling the organic fractionation of sea spray aerosol from bubble film Langmuir equilibria, Atmos. Chem. Phys., 14, 13601-13629, doi:10.5194/acp-14-13601-2014, 2014.

  17. Introductory lecture: atmospheric organic aerosols: insights from the combination of measurements and chemical transport models.

    PubMed

    Pandis, Spyros N; Donahue, Neil M; Murphy, Benjamin N; Riipinen, Ilona; Fountoukis, Christos; Karnezi, Eleni; Patoulias, David; Skyllakou, Ksakousti

    2013-01-01

    The formation, atmospheric evolution, properties, and removal of organic particulate matter remain some of the least understood aspects of atmospheric chemistry despite the importance of organic aerosol (OA) for both human health and climate change. Here, we summarize our recent efforts to deal with the chemical complexity of the tens of thousands of organic compounds in the atmosphere using the volatility-oxygen content framework (often called the 2D-Volatility Basis Set, 2D-VBS). Our current ability to measure the ambient OA concentration as a function of its volatility and oxygen to carbon (O:C) ratio is evaluated. The combination of a thermodenuder, isothermal dilution and Aerosol Mass Spectrometry (AMS) together with a mathematical aerosol dynamics model is a promising approach. The development of computational modules based on the 2D-VBS that can be used in chemical transport models (CTMs) is described. Approaches of different complexity are tested against ambient observations, showing the challenge of simulating the complex chemical evolution of atmospheric OA. The results of the simplest approach describing the net change due to functionalization and fragmentation are quite encouraging, reproducing both the observed OA levels and O : C in a variety of conditions. The same CTM coupled with source-apportionment algorithms can be used to gain insights into the travel distances and age of atmospheric OA. We estimate that the average age of OA near the ground in continental locations is 1-2 days and most of it was emitted (either as precursor vapors or particles) hundreds of kilometers away. Condensation of organic vapors on fresh particles is critical for the growth of these new particles to larger sizes and eventually to cloud condensation nuclei (CCN) sizes. The semivolatile organics currently simulated by CTMs are too volatile to condense on these tiny particles with high curvature. We show that chemical aging reactions converting these semivolatile

  18. A review of dicarboxylic acids and related compounds in atmospheric aerosols: Molecular distributions, sources and transformation

    NASA Astrophysics Data System (ADS)

    Kawamura, Kimitaka; Bikkina, Srinivas

    2016-03-01

    This review aims to update our understanding on molecular distributions of water-soluble dicarboxylic acids and related compounds in atmospheric aerosols with a focus on their geographical variability, size distribution, sources and formation pathways. In general, molecular distributions of diacids in aerosols from the continental sites and over the open ocean waters are often characterized by the predominance of oxalic acid (C2) followed by malonic acid (C3) and/or succinic acid (C4), while those sampled over the polar regions often follow the order of C4 ≥ C2 and C3. The most abundant and ubiquitous diacid is oxalic acid, which is principally formed via atmospheric oxidation of its higher homologues of long chain diacids and other pollution-derived organic precursors (e.g., olefins and aromatic hydrocarbons). However, its occurrence in marine aerosols is mainly due to the transport from continental outflows (e.g., East Asian outflow during winter/spring to the North Pacific) and/or governed by photochemical/aqueous phase oxidation of biogenic unsaturated fatty acids (e.g., oleic acid) and isoprene emitted from the productive open ocean waters. The long-range atmospheric transport of pollutants from mid latitudes to the Arctic in dark winter facilitates to accumulate the reactants prior to their intense photochemical oxidation during springtime polar sunrise. Furthermore, the relative abundances of C2 in total diacid mass showed similar temporal trends with downward solar irradiation and ambient temperatures, suggesting the significance of atmospheric photochemical oxidation processing. Compound-specific isotopic analyses of oxalic acid showed the highest δ13C among diacids whereas azelaic acid showed the lowest value, corroborating the significance of atmospheric aging of oxalic acid. On the other hand, other diacids gave intermediate values between these two diacids, suggesting that aging of oxalic acid is associated with 13C enrichment.

  19. A sub-decadal trend in diacids in atmospheric aerosols in eastern Asia

    NASA Astrophysics Data System (ADS)

    Kundu, S.; Kawamura, K.; Kobayashi, M.; Tachibana, E.; Lee, M.; Fu, P. Q.; Jung, J.

    2016-01-01

    Change in secondary organic aerosols (SOAs) has been predicted to be highly uncertain in the future atmosphere in Asia. To better quantify the SOA change, we examine the sub-decadal (2001-2008) trend in major surrogate compounds (C2-C10 diacids) of SOA in atmospheric aerosols from Gosan site on Cheju Island, South Korea. The Gosan site is influenced by pollution outflows from eastern Asia. The molecular distributions of diacids were characterized by the predominance of oxalic (C2) acid followed by malonic (C3) and succinic (C4) acids in each year. The seasonal variations in diacids in each year were characterized by the highest concentrations of saturated diacids in spring and unsaturated diacids in winter. The consistent molecular distributions and seasonal variations along with significantly similar air mass transport patterns are indicative of similar pollution sources for diacids in eastern Asia on a sub-decadal scale. However, the intensity of the pollution sources has increased as evidenced by the increases in major diacids at the rate of 3.9-47.4 % per year, particularly in April. The temporal variations in atmospheric tracer compounds (carbon monoxide, levoglucosan, 2-methyltetrols, pinic acid, glyoxylic acid, glyoxal and methylglyoxal) suggest that the increases in diacids are due to enhanced precursor emissions associated with more anthropogenic than biogenic activities followed by the compounds' chemical processing in the atmosphere. The trends in diacids contrast with the reported decreases in sulfate, nitrate and ammonium in recent years in eastern Asia. This study demonstrates that recent pollution control strategies in eastern Asia were not able to decrease organic acidic species in the atmosphere. The increases in water-soluble organic acid fraction could modify the aerosol organic composition and its sensitivity to climate relevant physical properties.

  20. Radiative effects of tropospheric aerosols on the evolution of the atmospheric boundary layer and its feedback on the haze formation

    NASA Astrophysics Data System (ADS)

    Wei, Chao; Su, Hang; Cheng, Yafang

    2016-04-01

    Planetary boundary layer (PBL) plays a key role in air pollution dispersion and influences day-to-day air quality. Some studies suggest that high aerosol loadings during severe haze events may modify PBL dynamics by radiative effects and hence enhance the development of haze. This study mainly investigates the radiative effects of tropospheric aerosols on the evolution of the atmospheric boundary layer by conducting simulations with Weather Research and Forecasting single-column model (WRF-SCM). We find that high aerosol loading in PBL depressed boundary layer height (PBLH). But the magnitude of the changes of PBLH after adding aerosol loadings in our simulations are small and can't explain extreme high aerosol concentrations observed. We also investigate the impacts of the initial temperature and moisture profiles on the evolution of PBL. Our studies show that the impact of the vertical profile of moisture is comparable with aerosol effects.

  1. The Influence of High Aerosol Concentration on Atmospheric Boundary Layer Temperature Stratification

    SciTech Connect

    Khaykin, M.N.; Kadygrove, E.N.; Golitsyn, G.S.

    2005-03-18

    Investigations of the changing in the atmospheric boundary layer (ABL) radiation balance as cased by natural and anthropogenic reasons is an important topic of the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) program. The influence of aerosol on temperature stratification of ABL while its concentration was extremely high within a long period of time was studied experimentally. The case was observed in Moscow region (Russia) with the transport of combustion products from peat-bog and forest fires in July-September, 2002. At this time the visibility was some times at about 100-300 m. Aerosol concentration measured by Moscow University Observatory and A.M. Obukhov Institute of Atmospheric Physics field station in Zvenigorod (55.7 N; 36.6 E) for several days was in 50-100 times more than background one (Gorchakov at al 2003). The high aerosol concentration can change the radiation balance at ABL, and so to change thermal stratification in ABL above the mega lopolis. For the analysis the data were used of synchronous measurements by MTP-5 (Microwave Temperature Profiler operating at wavelength 5 mm) in two locations, namely: downtown Moscow and country-side which is 50 km apart to the West (Zvenigorod station). (Kadygrov and Pick 1998; Westwater at al 1999; Kadygrov at al 2002). Zvenigorod station is located in strongly continental climate zone which is in between of the climates of ARM sites (NSANorth Slope of Alaska and SGP-Southern Great Plains). The town of Zvenigorod has little industry, small traffic volume and topography conductive to a good air ventilation of the town. For these reasons Zvenigorod can be considered as an undisturbed rural site. For the analysis some days were chosen with close meteorological parameters (average temperature, humidity, wind, pressure and cloud form) but strongly differing in aerosol concentration level.

  2. Chemical and aerosol characterisation of the troposphere over West Africa during the monsoon period as part of AMMA

    NASA Astrophysics Data System (ADS)

    Reeves, C. E.; Formenti, P.; Afif, C.; Ancellet, G.; Attié, J.-L.; Bechara, J.; Borbon, A.; Cairo, F.; Coe, H.; Crumeyrolle, S.; Fierli, F.; Flamant, C.; Gomes, L.; Hamburger, T.; Jambert, C.; Law, K. S.; Mari, C.; Jones, R. L.; Matsuki, A.; Mead, M. I.; Methven, J.; Mills, G. P.; Minikin, A.; Murphy, J. G.; Nielsen, J. K.; Oram, D. E.; Parker, D. J.; Richter, A.; Schlager, H.; Schwarzenboeck, A.; Thouret, V.

    2010-08-01

    During June, July and August 2006 five aircraft took part in a campaign over West Africa to observe the aerosol content and chemical composition of the troposphere and lower stratosphere as part of the African Monsoon Multidisciplinary Analysis (AMMA) project. These are the first such measurements in this region during the monsoon period. In addition to providing an overview of the tropospheric composition, this paper provides a description of the measurement strategy (flights performed, instrumental payloads, wing-tip to wing-tip comparisons) and points to some of the important findings discussed in more detail in other papers in this special issue. The ozone data exhibits an "S" shaped vertical profile which appears to result from significant losses in the lower troposphere due to rapid deposition to forested areas and photochemical destruction in the moist monsoon air, and convective uplift of ozone-poor air to the upper troposphere. This profile is disturbed, particularly in the south of the region, by the intrusions in the lower and middle troposphere of air from the southern hemisphere impacted by biomass burning. Comparisons with longer term data sets suggest the impact of these intrusions on West Africa in 2006 was greater than in other recent wet seasons. There is evidence for net photochemical production of ozone in these biomass burning plumes as well as in urban plumes, in particular that from Lagos, convective outflow in the upper troposphere and in boundary layer air affected by nitrogen oxide emissions from recently wetted soils. This latter effect, along with enhanced deposition to the forested areas, contributes to a latitudinal gradient of ozone in the lower troposphere. Biogenic volatile organic compounds are also important in defining the composition both for the boundary layer and upper tropospheric convective outflow. Mineral dust was found to be the most abundant and ubiquitous aerosol type in the atmosphere over Western Africa. Data

  3. Fine mode aerosol chemistry over a rural atmosphere near the north-east coast of Bay of Bengal in India

    NASA Astrophysics Data System (ADS)

    Adak, Anandamay; Chatterjee, Abhijit; Ghosh, Sanjay; Raha, Sibaji; Roy, Arindam

    2016-07-01

    A study was conducted on the chemical characterization of fine mode aerosol or PM2.5 over a rural atmosphere near the coast of Bay of Bengal in eastern India. Samples were collected and analyzed during March 2013 - February 2014. The concentration of PM2.5 was found span over a wide range from as low as 3 µg m-3 to as high as 180 µg m-3. The average concentration of PM2.5 was 62 µg m-3. Maximum accumulation of fine mode aerosol was observed during winter whereas minimum was observed during monsoon. Water soluble ionic species of fine mode aerosol were characterized over this rural atmosphere. In spite of being situated near the coast of Bay of Bengal, we observed significantly higher concentrations for anthropogenic species like ammonium and sulphate. The concentrations of these two species were much higher than the sea-salt aerosols. Ammonium and sulphate contributed around 30 % to the total fine mode aerosols. Even dust aerosol species like calcium also showed higher concentrations. Chloride to sodium ratio was found to be much less than that in standard sea-water indicating strong interaction between sea-salt and anthropogenic aerosols. Use of fertilizers in various crop fields and human and animal wastes significantly increased ammonium in fine mode aerosols. Dust aerosol species were accumulated in the atmosphere which could be due to transport of finer dust species from nearby metropolis or locally generated. Non-sea-sulphate and nitrate showed significant contributions in fine mode aerosols having both local and transported sources. Source apportionment shows prominent emission sources of anthropogenic aerosols from local anthropogenic activities and transported from nearby Kolkata metropolis as well.

  4. Carbonaceous aerosols and mineral dust in atmospheric outflow from the Indo-Gangetic Plain

    NASA Astrophysics Data System (ADS)

    Sarin, M.; Srinivas, B.; Rengarajan, R.

    2012-12-01

    Atmospheric carbonaceous aerosols and mineral dust over south and south-east Asia has been a subject of major debate over the past two decades because of their potential impact on the regional air quality and climate forcing. A comprehensive study through ground-based measurements and data-base for aerosol chemical composition (involving both organic and inorganic constituents) is, thus, essential to constrain the large uncertainties associated with the climate impact. Our systematic study from a downwind site (Kharagpur: 22.02N, 87.11E) in the Indo-Gangetic Plain (IGP) suggests large temporal variability in the atmospheric mass concentrations of mineral dust, organic and elemental carbon (OC, EC), water-soluble organic carbon (WSOC) and inorganic species (WSIS). This is attributed to seasonally varying anthropogenic emissions, their source strength, boundary layer dynamics, secondary aerosol formation and long-range transport of mineral dust from desert regions. Based on diagnostic ratios [OC/EC ≈ 7.0 ± 2.2, WSOC/OC ≈ 0.6 and K+/EC ≈ 0.48 ± 0.17], we document biomass burning emissions (wood-fuel and post-harvest agricultural-waste burning) as a major source of carbonaceous aerosols. The characteristic ratios: nss-SO42-/EC (3.9 ± 2.1), nss-SO42-/OC (0.61 ± 0.46), high abundance of SO42- (6.9 - 25.3 μg m-3) and SO42-/ΣWSIS = 45 - 77 % in the outflow provide better assessment of aerosol optical properties. The subsequent downwind transport of pollutants from the IGP significantly influences the chemical composition of aerosols over the Bay of Bengal. The dominance of aerosol SO42- in the marine atmospheric boundary layer (MABL) is evident from the wide-spread depletion of chloride with respect to sea-salt composition. The Ca/Al and Fe/Al ratios in the IGP-outflow, used as a proxy for the long-range transport of mineral dust, are consistent with those in the MABL. The mass closure for PM2.5 composition suggests that contribution of mineral dust (20

  5. The high field strength element budget of atmospheric aerosols (puy de Dôme, France)

    NASA Astrophysics Data System (ADS)

    Vlastelic, Ivan; Suchorski, Krzysztof; Sellegri, Karine; Colomb, Aurélie; Nauret, François; Bouvier, Laetitia; Piro, Jean-Luc

    2015-10-01

    High field strength elements (HFSE), including Zr, Hf, Nb, Ta and Ti have low solubility in aqueous fluids and partition into dense and resistant minerals. HFSE proved useful in studying terrestrial weathering and sediment transport, but little is known about their behavior during atmospheric processes, which play an important role in global sedimentary cycles. The atmospheric budget of HFSE is evaluated from the sequential dissolution of aerosol samples collected between 2011 and 2014 at puy de Dôme (1465 m elevation, French Massif Central). Aerosols were sampled during nighttime, while the site is generally located above the planetary boundary layer. Systematic, partial recovery of HFSE during gentle dissolution of aerosols indicates that resistant minerals are ubiquitous in air samples. Total dissolution of aerosols in pressure vessels reveals that Zr and Hf occur on average in sub-crustal abundance, which is consistent with the sampling site being dominantly influenced by oceanic air masses depleted in zircons. Conversely, zircon excess occasionally occurs in continental air masses, in particular those originating from northern Africa. Overall, the Hf/Nd ratio, a proxy for zircon fractionation, varies from 0.26 to 3.94 times the Upper Continental Crust (UCC) value, encompassing the range of worldwide loess. This wide compositional range is consistent with (1) the occurrence of coarse zircons (10-30 μm) in dust source, with possible local enrichments relative to bulk UCC in residual wind-winnowed soils, and (2) gravitational settling of coarse zircons during long-distance (>ca. 1000 km) transport. Niobium and Ta are systematically more abundant (by a mean factor of ∼3) in puy de Dôme aerosols than expected from average crustal or soil concentrations. The volume-weighted average Nb/Ta ratio of 15.5 ± 2.6 (1σ) is also higher than in bulk UCC (11.4-13.3). The positive Nb-Ta anomaly of free troposphere aerosols unlikely reflects a net Nb-Ta enrichment but

  6. Electrical Charging of Aerosols and Conductivity of Titan's Atmosphere

    NASA Technical Reports Server (NTRS)

    Borucki, W. J.; Whitten, R. C.; Tripathi, S. N.; Bakes, E. L. O.; Barth, E.

    2004-01-01

    We have used recent data on graphitic cloud particles in the atmosphere of Titan to compute the electrical charging of the particles (radii ranging from 0.01 microns to 0.26 microns). The charging on the nightside was rather similar to that obtained earlier except that charge distributions on the particles are now computed and recently obtained cloud particle sizes and density distributions were employed. The negative charge on particles of 0.26 microns peaked at 9 at 150 km altitude. The computations were repeated for the dayside with the addition of photoelectron emission by the particles as a result of the absorption of solar UV radiation. Particles (except the very smallest) now became positively charged with particles of radius 0.26 microns being charged up to +47. Next, very small particles (radii approx. 3 x 10 (sup -4) microns) of polycyclic aromatic hydrocarbons (PAHs) were introduced and treated as sources of negative ions since they could be either neutral or carry one negative charge. Moreover, they are mobile so that they had to be treated like molecular size negative ions although much more massive. They had the effect of substantially reducing the electron densities in the altitude range 190 to 310 km to values less than the negative PAH densities and increasing the peak electron charge on the larger particles. Particles of radius 0.26 microns bore peak charges of approx. +47 at altitudes of approx. 250 km. The simulated effect of PAHs on the nightside proved to be much less pronounced; at the peak negative PAH density, it was less than the electron density. The physics governing these results will be discussed.

  7. Origin of nitrocatechols and alkylated-nitrocatechols in atmospheric aerosol particles

    NASA Astrophysics Data System (ADS)

    Marchand, Nicolas; Sylvestre, Alexandre; Ravier, Sylvain; Detournay, Anais; Bruns, Emily; Temime-Roussel, Brice; Slowik, Jay; El Haddad, Imad; Prevot, Andre

    2013-04-01

    Biomass burning constitutes one of the major sources of aerosol particles in most of the environments during winter. If a lot of information is available in the literature on the primary fraction of biomass burning aerosol particles, almost nothing is known regarding the formation of Secondary Organic Aerosol (SOA) from the chemical mixture emitted by this source. Recently methylated nitrocatechol have been identified in atmospheric particles collected in winter. These compounds are strongly associated with biomass burning tracers such as levoglucosan and are suspected to be of secondary origin since they can be formed through the oxidation of cresol significantly emitted by biomass burning. However, nitrocatechols are particularly difficult to analyze using classical techniques like HPLC-MS or GC-MS. In the present study, we adopt a new analytical approach. Direct analysis in real time (DART), introduced by Cody et al. (2005), allows direct analysis of gases, liquids, solids and materials on surfaces. Thus, for particles collected onto filters, the sample preparation step is simplified as much as possible, avoiding losses and reducing to the minimum the analytical procedure time. Two analytic modes can be used. In positive mode, [MH]+ ions are formed by proton transfer reaction ; whereas in negative ionization mode, [MH]-, M- and [MO2]- ions are formed. DART source enables soft ionization and produces simple mass spectra suitable for analysis of complex matrices, like organic aerosol, in only a few seconds. For this study, the DART source was coupled to a Q-ToF mass spectrometer (Synapt G2 HDMS, Waters), with a mass resolution up to 40 000. The analysis of atmospheric aerosol samples, collected in Marseille during winter 2011 (APICE project), with the DART/Q-ToF approach highlighted the abundance of nitrocatechols and alkylated nitrocatechols. Their temporal trends were also very similar to those of levoglucosan or dihydroabietic acid well known tracers of biomass

  8. Impact of atmospheric aerosol from biomass burning on Amazon dry-season drought

    NASA Astrophysics Data System (ADS)

    Bevan, Suzanne L.; North, Peter R. J.; Grey, William M. F.; Los, Sietse O.; Plummer, Stephen E.

    2009-05-01

    It is becoming increasingly apparent that the future of the Amazon rainforest is under threat from both climate change and agricultural practices such as deforestation and biomass burning. Atmospheric aerosols are likely to play an important role in the interaction between deforestation, fire and drought, but until now, observations of aerosol optical depth (AOD) in this region have been limited to time series of less than 7 years for satellite retrievals, or to single-site measurements. Here we use a 13-year time series of Along Track Scanning Radiometer derived AOD measurements to examine the role of aerosols in biosphere-climate interactions over the Amazon. The seasonal cycle of AOD shows peaks in March and September. The September peak is caused by local dry-season biomass burning. The March peak has not been identified previously but is coincident with more remote fires located in northern South America. A decreasing trend in dry-season AOD between 1995 and 2000 and a subsequent increase from 2000 to 2004 can be explained by deforestation practices driven by economic forces, whereas even higher AOD levels in 2005 were probably caused more by the exceptional drought of that year. Throughout the time series, dry-season AODs are inversely correlated with dry-season precipitation, suggesting a positive feedback between aerosols and drought that may contribute to enhanced drought under climate change.

  9. Multi-Decadal Change of Atmospheric Aerosols and Their Effect on Surface Radiation

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Tan, Qian; Wild, Martin; Qian, Yun; Yu, Hongbin; Bian, Huisheng; Wang, Weiguo

    2012-01-01

    We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007, during which a suite of aerosol data from satellite observations and ground-based remote sensing and in-situ measurements have become available. We analyze the long-term global and regional aerosol optical depth and concentration trends and their relationship to the changes of emissions" and assess the role aerosols play in the multi-decadal change of solar radiation reaching the surface (known as "dimming" or "brightening") at different regions of the world, including the major anthropogenic source regions (North America, Europe, Asia) that have been experiencing considerable changes of emissions, dust and biomass burning regions that have large interannual variabilities, downwind regions that are directly affected by the changes in the source area, and remote regions that are considered to representing "background" conditions.

  10. Size-Resolved Chemical Analysis of Individual Atmospheric Aerosols near Barrow, Alaska

    NASA Astrophysics Data System (ADS)

    Gunsch, M.; Barrett, T. E.; Sheesley, R. J.; Pratt, K.

    2015-12-01

    Climate change is having noticeable impacts on the Arctic with increasing temperatures and decreasing sea ice coverage. Loss of sea ice is leading to development of oil and gas extraction activities and increased shipping in the Arctic. Arctic aerosol emissions are expected to increase with increasing anthropogenic activities and production of sea spray aerosol. These particles have significant climate effects, including interacting with radiation, forming cloud droplets and ice crystals, and depositing onto surfaces. Given the complexity and evolving nature of atmospheric particles, as well as the challenges associated with Arctic measurements, significant uncertainties remain in our understanding of particle sources, evolution, and impacts in the Arctic. To investigate the size and chemistry of individual particles in real-time, an aerosol time-of-flight mass spectrometer (ATOFMS) was deployed to Barrow, Alaska during August-September 2015. Parallel size-resolved number concentration measurements allow the quantification of number and mass concentrations of particles from various sources, including sea spray aerosol, biomass burning, and diesel combustion, for example.

  11. Investigating the Chemical Pathways to PAH- and PANH-Based Aerosols in Titan's Atmospheric chemistry

    NASA Technical Reports Server (NTRS)

    Sciamma-O'Brien, Ella Marion; Contreras, Cesar; Ricketts, Claire Louise; Salama, Farid

    2011-01-01

    A complex organic chemistry between Titan's two main constituents, N2 and CH4, leads to the production of more complex molecules and subsequently to solid organic aerosols. These aerosols are at the origin of the haze layers giving Titan its characteristic orange color. In situ measurements by the Ion Neutral Mass Spectrometer (INMS) and Cassini Plasma Spectrometer (CAPS) instruments onboard Cassini have revealed the presence of large amounts of neutral, positively and negatively charged heavy molecules in the ionosphere of Titan. In particular, benzene (C6H6) and toluene (C6H5CH3), which are critical precursors of polycyclic aromatic hydrocarbon (PAH) compounds, have been detected, suggesting that PAHs might play a role in the production of Titan s aerosols. Moreover, results from numerical models as well as laboratory simulations of Titan s atmospheric chemistry are also suggesting chemical pathways that link the simple precursor molecules resulting from the first steps of the N2-CH4 chemistry (C2H2, C2H4, HCN ...) to benzene, and to PAHs and nitrogen-containing PAHs (or PANHs) as precursors to the production of solid aerosols.

  12. Fluorescent water-soluble organic aerosols in the High Arctic atmosphere

    PubMed Central

    Fu, Pingqing; Kawamura, Kimitaka; Chen, Jing; Qin, Mingyue; Ren, Lujie; Sun, Yele; Wang, Zifa; Barrie, Leonard A.; Tachibana, Eri; Ding, Aijun; Yamashita, Youhei

    2015-01-01

    Organic aerosols are ubiquitous in the earth’s atmosphere. They have been extensively studied in urban, rural and marine environments. However, little is known about the fluorescence properties of water-soluble organic carbon (WSOC) or their transport to and distribution in the polar regions. Here, we present evidence that fluorescent WSOC is a substantial component of High Arctic aerosols. The ratios of fluorescence intensity of protein-like peak to humic-like peak generally increased from dark winter to early summer, indicating an enhanced contribution of protein-like organics from the ocean to Arctic aerosols after the polar sunrise. Such a seasonal pattern is in agreement with an increase of stable carbon isotope ratios of total carbon (δ13CTC) from −26.8‰ to −22.5‰. Our results suggest that Arctic aerosols are derived from a combination of the long-range transport of terrestrial organics and local sea-to-air emission of marine organics, with an estimated contribution from the latter of 8.7–77% (mean 45%). PMID:25920042

  13. Fine Iron Aerosols Are Internally Mixed with Nitrate in the Urban European Atmosphere.

    PubMed

    Dall'Osto, Manuel; Beddows, D C S; Harrison, Roy M; Onat, Burcu

    2016-04-19

    Atmospheric iron aerosol is a bioavailable essential nutrient playing a role in oceanic productivity. Using aerosol time-of-flight mass spectrometry (ATOFMS), the particle size (0.3-1.5 μm), chemical composition and mixing state of Fe-containing particles collected at two European urban sites (London and Barcelona) were characterized. Out of the six particle types accounting for the entire Fe-aerosol population, that arising from long-range transport (LRT) of fine Fe-containing particles (Fe-LRT, 54-82% across the two sites) was predominant. This particle type was found to be internally mixed with nitrate and not with sulfate, and likely mostly associated with urban traffic activities. This is in profound contrast with previous studies carried out in Asia, where the majority of iron-containing particles are mixed with sulfate and are of coal combustion origin. Other minor fine iron aerosol sources included mineral dust (8-11%), traffic brake wear material (1-17%), shipping/oil (1-6%), biomass combustion (4-13%) and vegetative debris (1-3%). Overall, relative to anthropogenic Asian Fe-sulfate dust, anthropogenic European dust internally mixed with additional key nutrients such as nitrate is likely to play a different role in ocean global biogeochemical cycles.

  14. Physical and chemical characterization of marine atmospheric aerosols over the North and South Pacific Oceans using single particle mass spectrometry

    NASA Astrophysics Data System (ADS)

    Furutani, H.; Jung, J.; Miura, K.; Uematsu, M.

    2010-12-01

    Physical and chemical properties of marine atmospheric aerosols were characterized and compared over the North and South Pacific Ocean during two trans-Pacific cruises (from Japan to Chile and Australia to Japan) during the period of January-June 2009, which cover broad region of Pacific Ocean from 40°N to 55°S and 140°E to 70°W. The measured parameters of aerosol properties were single particle size-resolved chemical composition (D = 100 ~ 1500 nm), cloud condensation nuclei (CCN) and condensation nuclei (CN) concentrations, size distribution from 10 nm to 5 μm, total aerosol nitrate and sulfate concentrations, and filter-based chemical composition. Trace gas concentrations of O3 and CO were also measured to aid air parcel categorization during the cruises. Reflecting larger anthropogenic emission in the Northern Hemisphere, pronounced concentration gradient between the North and South Pacific Ocean was observed for aerosol nitrate, CO, and O3. Aerosol sulfate also showed a similar concentration drop in the equatorial region, relatively higher sulfate concentration was observed in 30°S-40°S and 55°S regions, which was associated with increased aerosol methanesulfonic acid (MSA) concentration but little increase in local marine chlorophyll concentration, suggesting contribution of long-range transported marine biogenic sulfur from the high primary production area over the South Pacific high latitude region. Aerosol chemical classification by single particle chemical analysis revealed that certain aerosol types, such as biomass burning, elemental carbon, and elemental/organic carbon mixed type, were mainly observed in the North Pacific region, while several specific organic aerosol types with abundant aged organic and disulfur composition were identified in the South Pacific region. Further comparison of aerosol properties, aerosol sources, and atmospheric aerosol processing in the North and South Pacific Oceans will be discussed.

  15. Atmospheric Aging and Its Impacts on Physical Properties of Soot Aerosols: Results from the 2009 SHARP/SOOT Campaign

    NASA Astrophysics Data System (ADS)

    Zhang, R.; Khalizov, A. F.; Zheng, J.; Reed, C. C.; Collins, D. R.; Olaguer, E. P.

    2009-12-01

    Atmospheric aerosols impact the Earth energy balance directly by scattering solar radiation back to space and indirectly by changing the albedo, frequency, and lifetime of clouds. Carbon soot (or black carbon) produced from incomplete combustion of fossil fuels and biomass burning represents a major component of primary aerosols. Because of high absorption cross-sections over a broad range of the electromagnetic spectra, black carbon contributes significantly to climate change by direct radiative forcing and is the second most important component causing global warming after carbon dioxide. In areas identified as aerosol hotspots, which include many megacities, solar heating by soot-containing aerosols is roughly comparable to heating due to greenhouse gases. In addition, light absorbing soot aerosols may reduce photolysis rates at the surface level, producing a noticeable impact on photochemistry. Enhanced light absorption and scattering by soot can stabilize the atmosphere, retarding vertical transport and exacerbating accumulation of gaseous and particulate matter (PM) pollutants within the planetary boundary layer. Less surface heating and atmospheric stabilization may decrease formation of clouds, and warming in the atmosphere can evaporate existing cloud droplets by lowering relative humidity. Furthermore, soot-containing aerosols represent a major type of PM that has adverse effects on human health. When first emitted, soot particles are low-density aggregates of loosely connected primary spherules. Freshly emitted soot particles are typically hydrophobic, but may become cloud condensation nuclei (CCN) during atmospheric aging by acquiring hydrophilic coatings. Hygroscopic soot particles, being efficient CCN, can exert indirect forcing on climate. In this talk, results will be presented on measurements of soot properties during the 2009 SHARP/SOOT Campaign. Ambient aerosols and fresh soot particles injected into a captured air chamber were monitored to

  16. Atmospheric aerosols in Rome, Italy: sources, dynamics and spatial variations during two seasons

    NASA Astrophysics Data System (ADS)

    Struckmeier, Caroline; Drewnick, Frank; Fachinger, Friederike; Gobbi, Gian Paolo; Borrmann, Stephan

    2016-12-01

    Investigations on atmospheric aerosols and their sources were carried out in October/November 2013 and May/June 2014 consecutively in a suburban area of Rome (Tor Vergata) and in central Rome (near St Peter's Basilica). During both years a Saharan dust advection event temporarily increased PM10 concentrations at ground level by about 12-17 µg m-3. Generally, in October/November the ambient aerosol was more strongly influenced by primary emissions, whereas higher relative contributions of secondary particles (sulfate, aged organic aerosol) were found in May/June. Absolute concentrations of anthropogenic emission tracers (e.g. NOx, CO2, particulate polycyclic aromatic hydrocarbons, traffic-related organic aerosol) were generally higher at the urban location. Positive matrix factorization was applied to the PM1 organic aerosol (OA) fraction of aerosol mass spectrometer (HR-ToF-AMS) data to identify different sources of primary OA (POA): traffic, cooking, biomass burning and (local) cigarette smoking. While biomass burning OA was only found at the suburban site, where it accounted for the major fraction of POA (18-24 % of total OA), traffic and cooking were more dominant sources at the urban site. A particle type associated with cigarette smoke emissions, which is associated with a potential characteristic marker peak (m/z 84, C5H10N+, a nicotine fragment) in the mass spectrum, was only found in central Rome, where it was emitted in close vicinity to the measurement location. Regarding secondary OA, in October/November, only a very aged, regionally advected oxygenated OA was found, which contributed 42-53 % to the total OA. In May/June total oxygenated OA accounted for 56-76 % of the OA. Here a fraction (18-26 % of total OA) of a fresher, less oxygenated OA of more local origin was also observed. New particle formation events were identified from measured particle number concentrations and size distributions in May/June 2014 at both sites. While they were observed

  17. Biomonitoring of atmospheric pollution: a novel approach for the evaluation of natural and anthropogenic contribution to atmospheric aerosol particles.

    PubMed

    Caggiano, Rosa; Calamita, Giuseppe; Sabia, Serena; Trippetta, Serena

    2017-02-13

    The investigation of the potential natural and anthropogenic contribution to atmospheric aerosol particles by using lichen-bag technique was performed in the Agri Valley (Basilicata region, southern Italy). This is an area of international concern since it houses one of the largest European on-shore reservoirs and the biggest oil/gas pre-treatment plant (i.e., Centro Olio Val d'Agri (COVA)) within an anthropized context. In particular, the concentrations of 17 trace elements (Al, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Ti, and Zn) were measured in lichen bags exposed in 59 selected monitoring points over periods of 6 months (from October 2011 to April 2012) and 12 months (from October 2011 to October 2012). The general origin of the main air masses affecting the sampling site during the study period was assessed by the back trajectories clustering calculated using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The results allowed the identification and characterization of the crustal material, smoke, sea salt, sulfate, and anthropogenic trace element contributions to the atmospheric aerosol particles in the study area. Finally, the application of the trend surface analysis (TSA) allowed the study of the spatial distribution of the considered contributions highlighting the existence of a continuous broad variation of these contributions in the area of interest.

  18. Organic films on atmospheric aerosol particles, fog droplets, cloud droplets, raindrops, and snowflakes

    NASA Astrophysics Data System (ADS)

    Gill, P. S.; Graedel, T. E.; Weschler, C. J.

    1983-05-01

    If surface-active organic molecules are present as surface films, the transfer of gases into the atmospheric water system could be impeded, evaporation could be slowed, and the aqueous chemical reactions could be influenced. The results of new measurements of the surface tension of aqueous solutions of common atmospheric organic compounds (beta-pinene, n-hexanol, eugenol, and anethole) are reported, and it is shown that the compounds produce films with properties similar to those of the better known surfactants. It is concluded that organic films are probably common on atmospheric aerosol particles and that they may occur under certain circumstances on fog droplets, cloud droplets, and snowflakes. If they are present, they will increase the lifetimes of aerosol particles, fog droplets, and cloud droplets, both by inhibiting water vapor evaporation and by reducing the efficiency with which these atmospheric components are scavenged. It is thought likely that the transport of gaseous molecules into and out of the aqueous solution will be impeded by factors of several hundred or more when organic films are present.

  19. A comprehensive NMR structural study of Titan aerosol analogs: Implications for Titan's atmospheric chemistry

    NASA Astrophysics Data System (ADS)

    He, Chao; Smith, Mark A.

    2014-11-01

    Titan has a thick atmosphere composed primarily of nitrogen and methane. Complex organic chemistry induced by solar ultraviolet radiation and energetic particles, takes place in Titan's upper atmosphere, producing an optically thick reddish brown carbon based haze encircling this moon. The chemistry in Titan's atmosphere and its resulting chemical structures are still not fully understood in spite of a great many efforts being made. In our previous work, we have investigated the structure of the 13C and 15N labeled, simulated Titan haze aerosols (tholin) by NMR and identified several dominant small molecules in the tholin. Here we report our expanded structural investigation of the bulk of the tholin by more comprehensive NMR study. The NMR results show that the tholin materials are dominated by heavily nitrogenated compounds, in which the macromolecular structures are highly branched polymeric or oligomeric compounds terminated in methyl, amine, and nitrile groups. The structural characteristic suggest that the tholin materials are formed via different copolymerization or incorporation mechanisms of small precursors, such as HCN, CH2dbnd NH, NH3 and C2H2. This study helps to understand the formation process of nitrogenated organic aerosols in Titan's atmosphere and their prebiotic implications.

  20. Measurements of profiles of aerosol/cloud in the lower atmosphere using a lidar system

    NASA Astrophysics Data System (ADS)

    Gasmi, Khaled

    2016-10-01

    Preliminary measurements of profiles of aerosol/cloud in the lower atmosphere using a homemade stationary groundbased lidar system will be presented. In addition, information on basic characteristics and performance of the lidar system will be provided. Aerosol/Cloud lidar system in monostatic coaxial configuration uses the fundamental (1064 nm) and the second harmonic (532 nm) of a pulsed solid state Nd:YAG laser to provide information on the relative concentration and spatial distribution of aerosol particles and cloud water droplets. Beam expander is used to reduce the laser beam divergence before to be transmitted into the atmosphere. In this study, high-resolution vertical profiles from the near ground up to 15 km altitude are obtained. A Newtonian telescope of diameter 400 mm with an adjustable field of view (FOV) is used to collect the elastic backscattered signal. A photomultiplier tube (PMT) is used for the 532 nm wavelength detection channel, while an avalanche photodiode (APD) is used for the 1064 nm wavelength detection channel. The optoelectronic detection channels use two similar very high frequency preamplification circuit. Data are acquired with a nominal spatial resolution of 7.5 m using a 12-bit 20 MHz analog-to-digital converter (ADC) for each channel. Many functions, such as, range determination, background subtraction, digitization, and averaging are performed by the receiver subsystem. In addition, spatial resolution and linear dynamic range were optimized during signal processing.

  1. he Impact of Primary Marine Aerosol on Atmospheric Chemistry, Radiation and Climate: A CCSM Model Development Study

    SciTech Connect

    Keene, William C.; Long, Michael S.

    2013-05-20

    This project examined the potential large-scale influence of marine aerosol cycling on atmospheric chemistry, physics and radiative transfer. Measurements indicate that the size-dependent generation of marine aerosols by wind waves at the ocean surface and the subsequent production and cycling of halogen-radicals are important but poorly constrained processes that influence climate regionally and globally. A reliable capacity to examine the role of marine aerosol in the global-scale atmospheric system requires that the important size-resolved chemical processes be treated explicitly. But the treatment of multiphase chemistry across the breadth of chemical scenarios encountered throughout the atmosphere is sensitive to the initial conditions and the precision of the solution method. This study examined this sensitivity, constrained it using high-resolution laboratory and field measurements, and deployed it in a coupled chemical-microphysical 3-D atmosphere model. First, laboratory measurements of fresh, unreacted marine aerosol were used to formulate a sea-state based marine aerosol source parameterization that captured the initial organic, inorganic, and physical conditions of the aerosol population. Second, a multiphase chemical mechanism, solved using the Max Planck Institute for Chemistry's MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) system, was benchmarked across a broad set of observed chemical and physical conditions in the marine atmosphere. Using these results, the mechanism was systematically reduced to maximize computational speed. Finally, the mechanism was coupled to the 3-mode modal aerosol version of the NCAR Community Atmosphere Model (CAM v3.6.33). Decadal-scale simulations with CAM v.3.6.33, were run both with and without reactive-halogen chemistry and with and without explicit treatment of particulate organic carbon in the marine aerosol source function. Simulated results were interpreted (1) to evaluate influences of

  2. Do aerosols influence the diurnal variation of H2O2 in the atmosphere?

    NASA Astrophysics Data System (ADS)

    Liang, H.; Chen, Z.; Wu, Q.; Huang, D.; Zhao, Y.

    2013-12-01

    Hydrogen peroxide (H2O2) and organic peroxides are crucial reactive species that are involved in the cycling of HOx (OH and HO2) radicals and the formation of secondary inorganic and organic aerosols in the atmosphere. Despite the importance of peroxides, their formation and removal mechanisms with the coexistence of aerosols are as yet less well known. From June 10 to July 15 2013, summertime surface measurements for atmospheric peroxides were simultaneously obtained in urban Beijing (UB) and Gucheng (GC). The UB site is located in the northern downtown of Beijing city, while the GC site is a rural site located in the North China Plain and ~100 km southwest of Beijing. In both sites, the major peroxides were determined to be H2O2, methyl hydroperoxide (MHP), peroxyformic acid (PFA) and peroxyacetic acid (PAA). By comparing the concentrations of PFA and PAA in the gas phase and rainwater, for the first time, we estimated the Henry's law constant for PFA as ~210 M atm-1 at 298 K, a quarter of that for PAA. Interestingly, we observed different H2O2 profiles in the two sites as follows: (i) the average concentration of H2O2 in UB was 50% higher than that in GC; (ii) H2O2 in GC reached its peak concentration at around 15:30, whereas the peak concentration in UB appeared at as late as 21:00; and (iii) the daily variation of H2O2 in GC generally kept consistent with that of O3 and organic peroxides while it was not always the case in UB. These differences indicate a hitherto unrecognized storage-release mechanism for H2O2 in UB, that is, an extra sink in the noontime and an extra source in the early evening. The extra source of H2O2 would enhance the aerosol phase OH radical in the early evening by the Fenton reaction. A box model analysis shows that the impacts of aerosols were majorly responsible to this unrecognized mechanism, although NOx, regional transport and planet boundary layer height also contributed a minor part. Aerosols participated in the storage

  3. Fundamental Heterogeneous Reaction Chemistry Related to Secondary Organic Aerosols (SOA) in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Akimoto, H.

    2016-11-01

    Typical reaction pathways of formation of dicarboxylic acids, larger multifunctional compounds, oligomers, and organosulfur and organonitrogen compounds in secondary organic aerosols (SOA), revealed by laboratory experimental studies are reviewed with a short introduction to field observations. In most of the reactions forming these compounds, glyoxal, methyl glyoxal and related difunctional carbonyl compounds play an important role as precursors, and so their formation pathways in the gas phase are discussed first. A substantial discussion is then presented for the OH-initiated aqueous phase radical oxidation reactions of glyoxal and other carbonyls which form dicarboxylic acids, larger multifunctional compounds and oligomers, and aqueous-phase non-radical reactions which form oligomers, organosulfates and organonitrogen compounds. Finally, the heterogeneous oxidation reaction of gaseous O3, OH and NO3 with liquid and solid organic aerosols at the air-particle interface is discussed relating to the aging of SOA in the atmosphere.

  4. A tunable coherent CO2 lidar for measurements of atmospheric aerosol backscatter and attenuation

    NASA Technical Reports Server (NTRS)

    Menzies, R. T.

    1983-01-01

    A coherent laser radar system using a grating-tunable, injection-locked TEA-CO2 transmitter is being used to measure the altitude dependence of atmospheric aerosol backscatter and attenuation at a variety of CO2 laser wavelengths in the 9-11 micron region. Injection control of the TEA-CO2 laser allows one to obtain Single-Longitudinal-Mode (SLM) pulses which will follow the frequency of the injected radiation if the TEA laser cavity length is adjusted so that a cavity resonance is in proximity with the injected signal frequency, and if various additional conditions are satisfied. Requirements for generation of SLM pulses in this manner from a TEA CO2 laser with an unstable resonator cavity will be discussed. Procedures used for quantitative range-gated measurements of aerosol backscatter and attenuation will also be discussed.

  5. Theoretical and global scale model studies of the atmospheric sulfur/aerosol system

    NASA Technical Reports Server (NTRS)

    Kasibhatla, Prasad

    1996-01-01

    The primary focus during the third-phase of our on-going multi-year research effort has been on 3 activities. These are: (1) a global-scale model study of the anthropogenic component of the tropospheric sulfur cycle; (2) process-scale model studies of the factors influencing the distribution of aerosols in the remote marine atmosphere; and (3) an investigation of the mechanism of the OH-initiated oxidation of DMS in the remote marine boundary layer. In this paper, we describe in more detail our research activities in each of these areas. A major portion of our activities during the fourth and final phase of this project will involve the preparation and submission of manuscripts describing the results from our model studies of marine boundary-layer aerosols and DMS-oxidation mechanisms.

  6. The effect of rubber dam on atmospheric bacterial aerosols during restorative dentistry.

    PubMed

    Al-Amad, Suhail H; Awad, Manal A; Edher, Faraj M; Shahramian, Khalil; Omran, Tarek A

    Rotatory dental instruments generate atmospheric aerosols that settle on various surfaces, including the dentist's head. The aim of this study was to quantitatively assess bacterial contamination of the dentist's head and to evaluate whether it is affected by using a rubber dam. Senior dental students (n=52) were asked to wear autoclaved headscarves as collection media while performing restorative dental treatment with and without a rubber dam. Four points from each headscarf were swabbed for bacterial culture after 30min of operative work. Bacterial contamination was quantified by counting the colony-forming units. Regardless of the collection point, using a rubber dam was associated with more bacterial colony-forming units than not using a rubber dam (P=0.009). Despite its clinical value, the rubber dam seems to result in significantly higher aerosol levels on various areas of the dentist's head, requiring that dentists cover their heads with suitable protective wear.

  7. Spatial and temporal variations in the atmospheric aerosol optical depth at the ARM CART Site

    SciTech Connect

    Nash, T.M.; Cheng, M.D.

    1998-02-01

    In an effort to better characterize the inputs to radiative transfer models and research-grade global climate simulation models (GCMs) the columnar aerosol loading, measured as the aerosol optical depth (AOD), has been computed for five facilities within the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site. Characterization of the AOD reported here show clear evidence that the spatial and temporal gradient exists at a much finer linear scale than those of the CART site. The annual variations of median AOD are on the order of 0.30 at all five facilities. The Spearman correlation and varimax-rotated PCA indicated the AOD values vary consistently across the CART site. The Northwest corner facility (EF-1) was the single facility that behaved differently from the rest. This sub-GCM grid variation can not be ignored if the model is to be used to accurately predict future climate change.

  8. Equilibrium size of atmospheric aerosol sulfates as a function of the relative humidity

    NASA Astrophysics Data System (ADS)

    Koutrakis, Petros; Wolfson, Jack M.; Spengler, John D.; Stern, Bonnie; Franklin, Claire A.

    1989-05-01

    Size-fractionated acid aerosols were collected, using a microorifice cascade impactor, during the summer of 1986 in Dunnville, Ontario, as part of the Canadian Children Acute Respiratory Effects Study (CARES), sponsored by the Department of National Health and Welfare, Canada. Sulfate and hydrogen ions showed similar size distributions. The molar ratio of H+/SO42- varied little with particle size, but there was a considerable time-dependent variation in aerosol acid content. It was also found that there is a distinct relationship between the geometric mean aerodynamic diameter of sulfate, da, and ambient relative humidity (RH). Atmospheric sulfate particle sizes observed in this study were slightly higher than those found in laboratory experiments at corresponding humidities. However, considering the uncertainties involved, the agreement between the field and laboratory data was remarkable.

  9. Aqueous organic chemistry in the atmosphere: sources and chemical processing of organic aerosols.

    PubMed

    McNeill, V Faye

    2015-02-03

    Over the past decade, it has become clear that aqueous chemical processes occurring in cloud droplets and wet atmospheric particles are an important source of organic atmospheric particulate matter. Reactions of water-soluble volatile (or semivolatile) organic gases (VOCs or SVOCs) in these aqueous media lead to the formation of highly oxidized organic particulate matter (secondary organic aerosol; SOA) and key tracer species, such as organosulfates. These processes are often driven by a combination of anthropogenic and biogenic emissions, and therefore their accurate representation in models is important for effective air quality management. Despite considerable progress, mechanistic understanding of some key aqueous processes is still lacking, and these pathways are incompletely represented in 3D atmospheric chemistry and air quality models. In this article, the concepts, historical context, and current state of the science of aqueous pathways of SOA formation are discussed.

  10. Atmospheric oxidation of isoprene and 1,3-Butadiene: influence of aerosol acidity and Relative humidity on secondary organic aerosol

    EPA Science Inventory

    The effects of acidic seed aerosols on the formation of secondary organic aerosol (SOA)have been examined in a number of previous studies, several of which have observed strong linear correlations between the aerosol acidity (measured as nmol H+ per m3 air s...

  11. Response of an aerosol mass spectrometer to organonitrates and organosulfates and implications for atmospheric chemistry.

    PubMed

    Farmer, D K; Matsunaga, A; Docherty, K S; Surratt, J D; Seinfeld, J H; Ziemann, P J; Jimenez, J L

    2010-04-13

    Organonitrates (ON) are important products of gas-phase oxidation of volatile organic compounds in the troposphere; some models predict, and laboratory studies show, the formation of large, multifunctional ON with vapor pressures low enough to partition to the particle phase. Organosulfates (OS) have also been recently detected in secondary organic aerosol. Despite their potential importance, ON and OS remain a nearly unexplored aspect of atmospheric chemistry because few studies have quantified particulate ON or OS in ambient air. We report the response of a high-resolution time-of-flight aerosol mass spectrometer (AMS) to aerosol ON and OS standards and mixtures. We quantify the potentially substantial underestimation of organic aerosol O/C, commonly used as a metric for aging, and N/C. Most of the ON-nitrogen appears as NO(x)+ ions in the AMS, which are typically dominated by inorganic nitrate. Minor organonitrogen ions are observed although their identity and intensity vary between standards. We evaluate the potential for using NO(x)+ fragment ratios, organonitrogen ions, HNO(3)+ ions, the ammonium balance of the nominally inorganic ions, and comparison to ion-chromatography instruments to constrain the concentrations of ON for ambient datasets, and apply these techniques to a field study in Riverside, CA. OS manifests as separate organic and sulfate components in the AMS with minimal organosulfur fragments and little difference in fragmentation from inorganic sulfate. The low thermal stability of ON and OS likely causes similar detection difficulties for other aerosol mass spectrometers using vaporization and/or ionization techniques with similar or larger energy, which has likely led to an underappreciation of these species.

  12. Continuous standalone controllable aerosol/cloud droplet dryer for atmospheric sampling

    NASA Astrophysics Data System (ADS)

    Sjogren, S.; Frank, G. P.; Berghof, M. I. A.; Martinsson, B. G.

    2012-08-01

    We describe a general-purpose dryer designed for continuous sampling of atmospheric aerosol, where a specified relative humidity (RH) of the sample flow (lower than the atmospheric humidity) is required. It is often prescribed to measure the properties of dried aerosol, for instance for monitoring networks. The specific purpose of our dryer is to dry highly charged cloud droplets (maximum diameter approximately 25 μm) with minimum losses from the droplet size distribution entering the dryer as well as on the residual dry particle size distribution exiting the dryer. This is achieved by using a straight vertical downwards path from the aerosol inlet mounted above the dryer, and removing humidity to a dry closed loop airflow on the other side of a semi-permeable GORE-TEX membrane (total area 0.134 m2). The water vapour transfer coefficient, k, was measured to 4.6 × 10-7 kg m-2 s-1% RH-1 in the laboratory and is used for design purposes. A net water vapour transfer rate of up to 1.2 × 10-6 kg s-1 was achieved in the field. This corresponds to drying a 5.7 L min-1 (0.35 m3 h-1) aerosol sample flow from 100% RH to 27% RH at 293 K (with a drying air total flow of 8.7 L min-1). The system was used outdoors from 9 May until 20 October 2010, on the mountain Brocken (51.80° N, 10.67° E, 1142 m a.s.l.) in the Harz region in central Germany. Sample air relative humidity of less than 30% was obtained 72% of the time period. The total availability of the measurement system was > 94% during these five months.

  13. Continuous stand-alone controllable aerosol/cloud droplet dryer for atmospheric sampling

    NASA Astrophysics Data System (ADS)

    Sjogren, S.; Frank, G. P.; Berghof, M. I. A.; Martinsson, B. G.

    2013-02-01

    We describe a general-purpose dryer designed for continuous sampling of atmospheric aerosol, where a specified relative humidity (RH) of the sample flow (lower than the atmospheric humidity) is required. It is often prescribed to measure the properties of dried aerosol, for instance for monitoring networks. The specific purpose of our dryer is to dry cloud droplets (maximum diameter approximately 25 μm, highly charged, up to 5 × 102 charges). One criterion is to minimise losses from the droplet size distribution entering the dryer as well as on the residual dry particle size distribution exiting the dryer. This is achieved by using a straight vertical downwards path from the aerosol inlet mounted above the dryer, and removing humidity to a dry, closed loop airflow on the other side of a semi-permeable GORE-TEX membrane (total area 0.134 m2). The water vapour transfer coefficient, k, was measured to be 4.6 × 10-7 kg m-2 s-1% RH-1 in the laboratory (temperature 294 K) and is used for design purposes. A net water vapour transfer rate of up to 1.2 × 10-6 kg s-1 was achieved in the field. This corresponds to drying a 5.7 L min-1 (0.35 m3 h-1) aerosol sample flow from 100% RH to 27% RH at 293 K (with a drying air total flow of 8.7 L min-1). The system was used outdoors from 9 May until 20 October 2010, on the mountain Brocken (51.80° N, 10.67° E, 1142 m a.s.l.) in the Harz region in central Germany. Sample air relative humidity of less than 30% was obtained 72% of the time period. The total availability of the measurement system was >94% during these five months.

  14. CalWater 2 - Precipitation, Aerosols, and Pacific Atmospheric Rivers Experiment

    NASA Astrophysics Data System (ADS)

    Spackman, J. R.; Ralph, F. M.; Prather, K. A.; Cayan, D. R.; DeMott, P. J.; Dettinger, M. D.; Fairall, C. W.; Leung, L. R.; Rosenfeld, D.; Rutledge, S. A.; Waliser, D. E.; White, A. B.

    2014-12-01

    Emerging research has identified two phenomena that play key roles in the variability of the water supply and the incidence of extreme precipitation events along the West Coast of the United States. These phenomena include the role of (1) atmospheric rivers (ARs) in delivering much of the precipitation associated with major storms along the U.S. West Coast, and (2) aerosols—from local sources as well as those transported from remote continents—and their modulating effects on western U.S. precipitation. A better understanding of these processes is needed to reduce uncertainties in weather predictions and climate projections of extreme precipitation and its effects, including the provision of beneficial water supply. This presentation summarizes the science objectives and strategies to address gaps associated with (1) the evolution and structure of ARs including cloud and precipitation processes and air-sea interaction, and (2) aerosol interaction with ARs and the impact on precipitation, including locally-generated aerosol effects on orographic precipitation along the U.S. West Coast. Observations are proposed for multiple winter seasons as part of a 5-year broad interagency vision referred to as CalWater 2 to address these science gaps (http://esrl.noaa.gov/psd/calwater). In January-February 2015, a field campaign has been planned consisting of a targeted set of aircraft and ship-based measurements and associated evaluation of data in near-shore regions of California and in the eastern Pacific. In close coordination with NOAA, DOE's Atmospheric Radiation Measurement (ARM) program is also contributing air and shipborne facilities for ACAPEX (ARM Cloud Aerosol and Precipitation Experiment), a DOE-sponsored study complementing CalWater 2. Ground-based measurements from NOAA's HydroMeteorological Testbed (HMT) network in California and aerosol chemical instrumentation at Bodega Bay, California have been designed to add important near surface-level context for the

  15. A sub-decadal trend of diacids in atmospheric aerosols in East Asia

    NASA Astrophysics Data System (ADS)

    Kundu, S.; Kawamura, K.; Kobayashi, M.; Tachibana, E.; Lee, M.; Fu, P. Q.; Jung, J.

    2015-08-01

    The change of secondary organic aerosols (SOA) has been predicted to be highly uncertain in the future atmosphere in Asia. To better quantify the SOA change, we study a sub-decadal (2001-2008) trend of major surrogate compounds (C2-C10 diacids) of SOA in atmospheric aerosols from Gosan site in Jeju Island, South Korea. Gosan site is influenced by the pollution-outflows from East Asia. The molecular distribution of diacids was characterized by the predominance of oxalic (C2) acid followed by malonic (C3) and succinic (C4) acids in each year. The seasonal variations of diacids in each year were characterized by the highest concentrations of saturated diacids in spring and unsaturated diacids in winter. The consistent molecular distribution and seasonal variations are indicative of similar pollution sources for diacids in East Asia over a sub-decadal scale. However, the intensity of the pollution sources has increased as evidenced by the increases of major diacids at the rate of 3.9-47.4 % year-1 particularly in April. The temporal variations of atmospheric tracer compounds (CO, levoglucosan, 2-methyltetrols, pinic acid, glyoxylic acid, glyoxal and methylglyoxal) suggest that the increases of diacids are due to an enhanced precursor emissions associated with more anthropogenic than biogenic activities followed by their chemical processing in the atmosphere. The trends of diacids are opposite to the reported decreases of sulfate, nitrate and ammonium in the recent years in East Asia. This study demonstrates that recent pollution control strategies in East Asia could not decrease organic acidic species in the atmosphere. If the current rates of increases continue, the organic acid- and water-soluble fractions of SOA could increase significantly in the future atmosphere in East Asia.

  16. Laboratory Experiments and Instrument Development for the Study of Atmospheric Aerosols

    SciTech Connect

    Davidovits, Paul

    2011-12-10

    Soot particles are generated by incomplete combustion of fossil and biomass fuels. Through direct effects clear air aerosols containing black carbon (BC) such as soot aerosols, absorb incoming light heating the atmosphere, while most other aerosols scatter light and produce cooling. Even though BC represents only 1-2% of the total annual emissions of particulate mass to the atmosphere, it has been estimated that the direct radiative effect of BC is the second-most important contributor to global warming after absorption by CO2. Ongoing studies continue to underscore the climate forcing importance of black carbon. However, estimates of the radiative effects of black carbon on climate remain highly uncertain due to the complexity of particles containing black carbon. Quantitative measurement of BC is challenging because BC often occurs in highly non-spherical soot particles of complex morphology. Freshly emitted soot particles are typically fractal hydrophobic aggregates. The aggregates consist of black carbon spherules with diameters typically in the range of about 15-40 nm, and they are usually coated by adsorbed polyaromatic hydrocarbons (PAHs) produced during combustion. Diesel-generated soot particles are often emitted with an organic coating composed primarily of lubricating oil and unburned fuel, as well as well as PAH compounds. Sulfuric acid has also been detected in diesel and aircraft-emitted soot particles. In the course of aging, these particle coatings may be substantially altered by chemical reactions and/or the deposition of other materials. Such processes transform the optical and CCN properties of the soot aerosols in ways that are not yet well understood. Our work over the past seven years consisted of laboratory research, instrument development and characterization, and field studies with the central focus of improving our understanding of the black carbon aerosol climate impacts. During the sixth year as well as during this seventh year (no

  17. Factors controlling the solubility of trace metals in atmospheric aerosols over the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Nikolaou, Panagiota; Mihalopoulos, Nikolaos; Kanakidou, Maria

    2015-04-01

    Atmospheric input of aerosols is recognized, as an important source of nutrients, for the oceans. The chemical interactions between aerosols and varying composition of air masses lead to different coating of their surfaces with sulfate, nitrate and organic compounds, increasing their solubility and their role as a carrier of nutrients and pollutants in ecosystems. Recent works have highlighted that atmospheric inputs of nutrients and trace metals can considerably influence the marine ecosystem functioning at semi-enclosed or enclosed water bodies such as the eastern Mediterranean. The current work aims to determine the sources and the factors controlling the variability of nutrients in the eastern Mediterranean. Special focus has been given on trace elements solubility, considered either as key nutrients for phytoplankton growth such as iron (Fe), phosphorus (P) or inhibitors such as copper (Cu). This has been accomplished by analyzing size segregated aerosol samples collected at the background site of Finokalia in Crete for an entire year. Phosphorus concentrations indicate important increases in air masses influenced both by anthropogenic activities in the northeast European countries and by dust outbreaks. The last is confirmed by the correlation observed between total P and dust concentrations and by the air mass backward trajectories computed by running the NOAA Hysplit Model (Hybrid Single - Particle Langrangian Integrated Trajectory (http://www.arl.noaa.gov/ready/hysplit4.html). Overall 73% of total P has been found to be associated with anthropogenic sources. The solubility of P and Fe has been found to be closely related to the acidity (pH) and dust amount in aerosols. The aerosol pH was predicted using thermodynamic modeling (ISORROPIA-II), meteorological observations (RH, T), and gas/particle observations. More specifically P and Fe solubility appears to be inversely related to the crustal elements levels, while it increases in acidic environment. The

  18. The long-range transport of atmospheric aerosols from South Asia to Himalayas

    NASA Astrophysics Data System (ADS)

    Cong, Zhiyuan; Kang, Shichang; Kawamura, Kimitaka

    2016-04-01

    High levels of carbonaceous aerosol exist over South Asia, the area adjacent to the Himalayas and Tibetan Plateau. Little is known about if they can be transported across the Himalayas, and as far inland as the Tibetan Plateau. To resolve such scientific questions, aerosol samples were collected weekly from August 2009 to July 2010 at Qomolangma (Mt. Everest) Station for Atmospheric and Environmental Observation and Research(QOMS, 4276 m a.s.l.). In the laboratory, major ions, elemental carbon, organic carbon, levoglucosan, water-soluble organic carbon, and organic acids were analyzed. The concentration levels of OC and EC at QOMS are comparable to those at high-elevation sites on the southern slopes of the Himalayas (Langtang and NCO-P), but 3 to 6 times lower than those at Manora Peak, India, and Godavari, Nepal. Sulfate was the most abundant anion species followed by nitrate. The dust loading, represented by Ca2+ concentration, was relatively constant throughout the year. OC, EC and other ionic species (NH+4 , K+, NO- and SO2-) exhibited a pronounced peak in the pre-monsoon period and a minimum in the monsoon season, being similar to the seasonal trends of aerosol compo-sition reported previously from the southern slope of the Himalayas. The strong correlation of OC and EC in QOMS aerosols with K+ and levoglucosan indicates that they mainly originated from biomass burning. Molecular distributions of dicarboxylic acids and related compounds (malonic acid/ succinic acid, maleic acid/fumaric acid) further support this finding. The fire spots observed by MODIS and backward air-mass trajectories further demonstrate that in pre-monsoon season, agricultural and forest fires in northern India and Nepal were most likely sources of carbonaceous aerosol at QOMS. In addition to large-scale atmospheric circulation, the unique mountain/valley breeze system can also have an important effect on air-pollutant transport.With the consideration of the darkening force of

  19. Atmospheric aerosol compositions and sources at two national background sites in northern and southern China

    NASA Astrophysics Data System (ADS)

    Zhu, Qiao; He, Ling-Yan; Huang, Xiao-Feng; Cao, Li-Ming; Gong, Zhao-Heng; Wang, Chuan; Zhuang, Xin; Hu, Min

    2016-08-01

    Although China's severe air pollution has become a focus in the field of atmospheric chemistry and the mechanisms of urban air pollution there have been researched extensively, few field sampling campaigns have been conducted at remote background sites in China, where air pollution characteristics on a larger scale are highlighted. In this study, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), together with an Aethalometer, was deployed at two of China's national background sites in northern (Lake Hongze site; 33.23° N, 118.33° E; altitude 21 m) and southern (Mount Wuzhi site; 18.84° N, 109.49° E; altitude 958 m) China in the spring seasons in 2011 and 2015, respectively, in order to characterize submicron aerosol composition and sources. The campaign-average PM1 concentration was 36.8 ± 19.8 µg m-3 at the northern China background (NCB) site, which was far higher than that at the southern China background (SCB) site (10.9 ± 7.8 µg m-3). Organic aerosol (OA) (27.2 %), nitrate (26.7 %), and sulfate (22.0 %) contributed the most to the PM1 mass at NCB, while OA (43.5 %) and sulfate (30.5 %) were the most abundant components of the PM1 mass at SCB, where nitrate only constituted a small fraction (4.7 %) and might have contained a significant amount of organic nitrates (5-11 %). The aerosol size distributions and organic aerosol elemental compositions all indicated very aged aerosol particles at both sites. The OA at SCB was more oxidized with a higher average oxygen to carbon (O / C) ratio (0.98) than that at NCB (0.67). Positive matrix factorization (PMF) analysis was used to classify OA into three components, including a hydrocarbon-like component (HOA, attributed to fossil fuel combustion) and two oxygenated components (OOA1 and OOA2, attributed to secondary organic aerosols from different source areas) at NCB. PMF analysis at SCB identified a semi-volatile oxygenated component (SV-OOA) and a low-volatility oxygenated

  20. Long-Range Transport of Perchlorate Observed in the Atmospheric Aerosols Collected at Okinawa Island, Japan

    NASA Astrophysics Data System (ADS)

    Handa, D.; Okada, K.; Kuroki, Y.; Nakama, Y.; Nakajima, H.; Arakaki, T.; Tanahara, A.; Oomori, T.; Miyagi, T.; Kadena, H.; Ishizaki, T.; Nakama, F.

    2007-12-01

    The study of perchlorate has become quite active in the U.S. in the last several years. Perchlorate has been recognized as a new environmental pollutant and it attracted much attention quickly in the world. The health concern about perchlorate stems from the fact that it displaces iodide in the thyroid gland, while iodine-containing thyroid hormones are essential for proper neural development from the fetal stage through the first years of life. In this study, we determined the concentrations of perchlorate ion present in the atmospheric aerosols collected in Okinawa Island, Japan. We then examined the relationships between the perchlorate concentrations and the environmental parameters and the climatic conditions peculiar to Okinawa. Bulk aerosol samples were collected on quartz filters by using a high volume air sampler at Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS). Each sampling duration was one week. The quartz filters with aerosols were stirred with Milli-Q pure water for three hours before perchlorate ion was extracted. The extracted perchlorate ion concentrations were determined by ion chromatography (ICS-2000, DIONEX). The mean perchlorate concentration for the samples collected at CHAAMS was 1.83 ng/m3, and the minimum was 0.18 ng/m3. The samples collected during November 21-27, 2005, January 23-30, 2006 and April 24-01, 2006 had highest perchlorate concentrations. For these three samples, we performed back trajectory analysis, and found that the air mass for the three samples arrived from the Asian continent. A relatively strong correlation (r2 = 0.55) was found between perchlorate and nss-sulfate concentrations for the CHAAMS samples. Furthermore, we analyzed perchlorate in the soils and the fertilizers used for sugar cane farming around the CHAAMS area. The Milli-Q extract of the soil and the fertilizers did not contain any detectable levels of perchlorate ions. Therefore, it was suggested that perchlorate found in the atmospheric

  1. Comparison Between Lidar and Nephelometer Measurements of Aerosol Hygroscopicity at the Southern Great Plains Atmospheric Radiation Measurement Site

    NASA Technical Reports Server (NTRS)

    Pahlow, M.; Feingold, G.; Jefferson, A.; Andrews, E.; Ogren, J. A.; Wang, J.; Lee, Y.-N.; Ferrare, R. A.

    2004-01-01

    Aerosol hygroscopicity has a significant effect on radiative properties of aerosols. Here a lidar method, applicable to cloud-capped, well-mixed atmospheric boundary layers, is employed to determine the hygroscopic growth factor f(RH) under unperturbed, ambient atmospheric conditions. The data used for the analysis were collected under a wide range of atmospheric aerosol levels during both routine measurement periods and during the intensive operations period (IOP) in May 2003 at the Southern Great Plains (SGP) Climate Research Facility in Oklahoma, USA, as part of the Atmospheric Radiation Measurement (ARM) program. There is a good correlation (approx. 0.7) between a lidar-derived growth factor (measured over the range 85% RH to 96% RH) with a nephelometer-derived growth factor measured over the RH range 40% to 85%. For these RH ranges, the slope of the lidar-derived growth factor is much steeper than that of the nephelometer-derived growth factor, reflecting the rapid increase in particle size with increasing RH. The results are corroborated by aerosol model calculations of lidar and nephelometer equivalent f(RH) based on in situ aerosol size and composition measurements during the IOP. It is suggested that the lidar method can provide useful measurements of the dependence of aerosol optical properties on relative humidity, and under conditions closer to saturation than can currently be achieved with humidified nephelometers.

  2. Climate change and the middle atmosphere. II - The impact of volcanic aerosols

    NASA Technical Reports Server (NTRS)

    Rind, D.; Balachandran, N. K.; Suozzo, R.

    1992-01-01

    The response of the middle atmosphere to an increase in stratospheric aerosols, normally associated with increased volcanic activity, is investigated. The aerosols are found to induce a direct stratospheric response, with warming in the tropical lower stratosphere, and cooling at higher latitudes. On the shorter time scales, this radiative effect increases tropospheric static stability at low- to midlatitudes, which reduces the intensity of the Hadley cell and Ferrel cell. There is an associated increase in tropospheric standing wave energy and a decrease in midlatitude west winds, which result in additional wave energy propagation into the stratosphere at lower midlatitudes in both hemispheres. On the longer time scale, a strong hemispheric asymmetry arises. In the Northern Hemisphere eddy energy decreases, as does the middle-atmosphere residual circulation, and widespread stratospheric cooling results. In the Southern Hemisphere, the large increase in sea ice increases the tropospheric latitudinal temperature gradient, leading to increased eddy energy, an increased middle-atmosphere residual circulation, and some high-latitude stratospheric warming.

  3. The ABC-Pyramid Atmospheric Research Observatory in Himalaya for aerosol, ozone and halocarbon measurements.

    PubMed

    Bonasoni, P; Laj, P; Angelini, F; Arduini, J; Bonafè, U; Calzolari, F; Cristofanelli, P; Decesari, S; Facchini, M C; Fuzzi, S; Gobbi, G P; Maione, M; Marinoni, A; Petzold, A; Roccato, F; Roger, J C; Sellegri, K; Sprenger, M; Venzac, H; Verza, G P; Villani, P; Vuillermoz, E

    2008-03-01

    In this work we present the new ABC-Pyramid Atmospheric Research Observatory (Nepal, 27.95 N, 86.82 E) located in the Himalayas, specifically in the Khumbu valley at 5079 m a.s.l. This measurement station has been set-up with the aim of investigating natural and human-induced environmental changes at different scales (local, regional and global). After an accurate instrumental set-up at ISAC-CNR in Bologna (Italy) in autumn 2005, the ABC-Pyramid Observatory for aerosol (physical, chemical and optical properties) and trace gas measurements (ozone and climate altering halocarbons) was installed in the high Khumbu valley in February 2006. Since March 2006, continuous measurements of aerosol particles (optical and physical properties), ozone (O3) and meteorological parameters as well as weekly samplings of particulate matter (for chemical analyses) and grab air samples for the determination of 27 halocarbons, have been carried out. These measurements provide data on the typical atmospheric composition of the Himalayan area between India and China and make investigations of the principal differences and similarities between the monsoon and pre-monsoon seasons possible. The study is carried out within the framework of the Ev-K2-CNR "SHARE-Asia" (Stations at High Altitude for Research on the Environment in Asia) and UNEP-"ABC" (Atmospheric Brown Clouds) projects. With the name of "Nepal Climate Observatory-Pyramid" the station is now part of the Observatory program of the ABC project.

  4. Stratospheric denitrification due to polar aerosol formation: Implications for a future atmosphere with increased CO2

    NASA Astrophysics Data System (ADS)

    Pitari, Giovanni; Ricciardulli, Lucrezia

    The amount of stratospheric denitrification produced by NAT aerosol formation is studied with a photochemical two-dimensional model which includes the effects of zonal asymmetries of the temperature field. The model photochemistry is coupled with a microphysical code for aerosol formation and growth, so that the permanent loss of stratospheric nitric acid and water vapor may be taken into account. The model results for nitric acid relative to the atmospheric chemical composition of 1980 are compared with LIMS data. We show that the level of denitrification may rise substantially if the polar vortex cools down, as it could be the case in a future atmosphere richer in carbon dioxide. A three-dimensional model is used to calculate the temperature perturbation due to an increase of CO2 from 335 ppmv of 1980 (baseline) up to 500 ppmv (predicted for 2050). The photochemical model adopting these new temperatures predicts an average 20% HNO3 column decrease poleward of 45N with respect to baseline. One consequence is that the relative weight of the NOx catalytic cycle for O3 destruction decreases with respect to the present atmosphere.

  5. Optical phase curves as diagnostics for aerosol composition in exoplanetary atmospheres

    NASA Astrophysics Data System (ADS)

    Oreshenko, Maria; Heng, Kevin; Demory, Brice-Olivier

    2016-04-01

    Optical phase curves have become one of the common probes of exoplanetary atmospheres, but the information they encode has not been fully elucidated. Building on a diverse body of work, we upgrade the Flexible Modelling System to include scattering in the two-stream, dual-band approximation and generate plausible, three-dimensional structures of irradiated atmospheres to study the radiative effects of aerosols or condensates. In the optical, we treat the scattering of starlight using a generalization of Beer's law that allows for a finite Bond albedo to be prescribed. In the infrared, we implement the two-stream solutions and include scattering via an infrared scattering parameter. We present a suite of four-parameter general circulation models for Kepler-7b and demonstrate that its climatology is expected to be robust to variations in optical and infrared scattering. The westward and eastward shifts of the optical and infrared phase curves, respectively, are shown to be robust outcomes of the simulations. Assuming micron-sized particles and a simplified treatment of local brightness, we further show that the peak offset of the optical phase curve is sensitive to the composition of the aerosols or condensates. However, to within the measurement uncertainties, we cannot distinguish between aerosols made of silicates (enstatite or forsterite), iron, corundum or titanium oxide, based on a comparison to the measured peak offset (41° ± 12°) of the optical phase curve of Kepler-7b. Measuring high-precision optical phase curves will provide important constraints on the atmospheres of cloudy exoplanets and reduce degeneracies in interpreting their infrared spectra.

  6. Polar organic marker compounds in atmospheric aerosols: Determination, time series, size distributions and sources

    NASA Astrophysics Data System (ADS)

    Kourtchev, Ivan

    Terrestrial vegetation releases substantial amounts of reactive volatile organic compounds (VOCs; e.g., isoprene, monoterpenes) into the atmosphere. The VOCs can be rapidly photooxidized under conditions of high solar radiation, yielding products that can participate in new particle formation and growth processes above forests. This thesis focuses on the characterization, identification and quantification of oxidation products of biogenic VOC (BVOCs) as well as other species (tracer compounds) that provide information on aerosol sources and source processes. Atmospheric aerosols from various forested sites (i.e., Hyytiala, southern Finland; Rondonia, Brazil; K-Puszta, Hungary and Julich, Germany) were analyzed with Gas Chromotography/Mass Spectrometry (GC/MS) using analytical procedure that targets polar organic compounds. The study demonstrated that isoprene (i.e., 2-methyerythritol, 2-methylthreitol, 2-methylglyceric acid and C5-alkene triols (2-methyl-1,3,4-trihydroxy-l-butene (cis and trans) and 3 methyl-2,3,4-trihydroxy-1-butene)) and monoterpene (pinic acid, norpinic acid, 3-hydroxyglutaric acid and 3-methyl-1,2,3-butanetricarboxylic acid) oxidation products were present in substantial concentrations in atmospheric aerosols suggesting that oxidation of BVOC from the vegetation is an important process in all studied sites. On the other hand, presence of levoglucosan, biomass burning marker, especially in Amazonian rain forest site at Rondonia, Brazil, pointed that all sites were affected by anthropogenic activities, namely biomass burning. Other identified compounds included plyols, arabitol, mannitol and erythritol, which are marker compounds for fungal spores and monosacharides, glucose and fructose, markers for plant polens. Temporal variations as well as mass size distributions of the detected species confirmed the possible formation mechanisms of marker compounds.

  7. Sources and radiative effects of wintertime black carbon aerosols in an urban atmosphere in east India.

    PubMed

    Verma, S; Pani, S K; Bhanja, S N

    2013-01-01

    We carried out an analysis of black carbon (BC) surface mass concentration, its radiative effects, and sources of origin in an urban atmosphere in east India, during winter season, through ground-based measurements and application of modelling tools. BC surface mass concentration exhibited diurnal variation with their higher values and a larger variability during evening to early morning hours than during daytime (1100-1600 h, Local Time, LT) hours. Daytime mean surface BC mass concentration and BC mass fraction in total aerosol (size range 0.23-20 μm) and in submicronic aerosol (size range 0.23-1 μm) during the study period, corresponding to the well-mixed atmospheric layer were 11 μg m(-3), 3-10%, and 9-16% respectively. The mean BC optical depth (BC-AOD) and BC-AOD fraction at 0.5 μm were estimated in an optical model as 0.11 and 13% respectively. Mean shortwave aerosol radiative forcing due to BC at top-of-atmosphere (TOA) during the study period was found to be +0.94 Wm(-2), which is about 59% the global mean radiative forcing due to carbon-dioxide gases. Estimates from BC simulations in a general circulation model showed BC surface concentration and BC optical depth in east India are primarily attributed to emissions from biofuel and fossil fuel combustion. Most of BC surface concentration (95%) and BC optical depth (60%) are contributed by emissions arising from the Indo-Gangetic plain (IGP) but there is a significant influence to BC columnar loading through elevated transport channels attributed mainly to emissions from open biomass burning from distant regions outside IGP.

  8. Mass-based hygroscopicity parameter interaction model and measurement of atmospheric aerosol water uptake

    NASA Astrophysics Data System (ADS)

    Mikhailov, E.; Merkulov, V.; Vlasenko, S.; Rose, D.; Pöschl, U.

    2011-11-01

    In this study we derive and apply a mass-based hygroscopicity parameter interaction model for efficient description of concentration-dependent water uptake by atmospheric aerosol particles. The model approach builds on the single hygroscopicity parameter model of Petters and Kreidenweis (2007). We introduce an observable mass-based hygroscopicity parameter κm, which can be deconvoluted into a dilute intrinsic hygroscopicity parameter (κm,∞) and additional self- and cross-interaction parameters describing non-ideal solution behavior and concentration dependencies of single- and multi-component systems. For sodium chloride, the κm-interaction model (KIM) captures the observed concentration and humidity dependence of the hygroscopicity parameter and is in good agreement with an accurate reference model based on the Pitzer ion-interaction approach (Aerosol Inorganic Model, AIM). For atmospheric aerosol samples collected from boreal rural air and from pristine tropical rainforest air (secondary organic aerosol) we present first mass-based measurements of water uptake over a wide range of relative humidity (1-99%) obtained with a new filter-based differential hygroscopicity analyzer (FDHA) technique. By application of KIM to the measurement data we can distinguish three different regimes of hygroscopicity in the investigated aerosol samples: (I) A quasi-eutonic regime at low relative humidity (~60% RH) where the solutes co-exist in an aqueous and non-aqueous phase; (II) a gradually deliquescent regime at intermediate humidity (~60%-90% RH) where different solutes undergo gradual dissolution in the aqueous phase; and (III) a dilute regime at high humidity (≳90% RH) where the solutes are fully dissolved approaching their dilute intrinsic hygroscopicity. The characteristic features of the three hygroscopicity regimes are similar for both samples, while the RH threshold values vary as expected for samples of different chemical composition. In each regime, the

  9. Improvement and Application of Atmospheric Radiative Transfer Models for Prediction of the Climatic Effects of Aerosol

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.; Mlawer, Eli J.; Sokolik, Irina N.; Clough, Shepard A.; Toon, Owen B.

    1998-01-01

    This paper presents a radiative transfer model that has been developed to accurately predict the atmospheric radiant flux in both the infrared and the solar spectrum with a minimum of computational effort. The model is designed to be included in numerical climate models. To assess the accuracy of the model, the results are compared to other more detailed models for several standard cases in the solar and thermal spectrum. As the thermal spectrum has been treated in other publications, we focus here on the solar part of the spectrum. We perform several example calculations focussing on the question of absorption of solar radiation by gases and aerosols.

  10. Improvement and Application of Atmospheric Radiative Transfer Models for Prediction of the Climatic Effects of Aerosol

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.

    1998-01-01

    This paper presents a radiative transfer model that has been developed to accurately predict the atmospheric radiant flux in both the infrared and the solar spectrum with a minimum of computational effort. The model is designed to be included in numerical climate models. To assess the accuracy of the model, the results are compared to other more detailed models for several standard cases in the solar and thermal spectrum. As the thermal spectrum has been treated in other publications we focus here on the solar part of the spectrum. We perform several example calculations focussing on the question of absorption of solar radiation by gases and aerosols.

  11. A survey of light-scattering techniques used in the remote monitoring of atmospheric aerosols