WorldWideScience

Sample records for aerosol ratio program

  1. Surrogate/spent fuel sabotage : aerosol ratio test program and Phase 2 test results.

    Energy Technology Data Exchange (ETDEWEB)

    Borek, Theodore Thaddeus III; Thompson, N. Slater (U.S. Department of Energy); Sorenson, Ken Bryce; Hibbs, R.S. (U.S. Department of Energy); Nolte, Oliver (Fraunhofer Institut fur Toxikologie und Experimentelle Medizin, Germany); Molecke, Martin Alan; Autrusson, Bruno (Institut de Radioprotection et de Surete Nucleaire, France); Young, F. I. (U.S. Nuclear Regulatory Commission); Koch, Wolfgang (Fraunhofer Institut fur Toxikologie und Experimentelle Medizin, Germany); Brochard, Didier (Institut de Radioprotection et de Surete Nucleaire, France); Pretzsch, Gunter Guido (Gesellschaft fur Anlagen- und Reaktorsicherheit, Germany); Lange, Florentin (Gesellschaft fur Anlagen- und Reaktorsicherheit, Germany)

    2004-05-01

    A multinational test program is in progress to quantify the aerosol particulates produced when a high energy density device, HEDD, impacts surrogate material and actual spent fuel test rodlets. This program provides needed data that are relevant to some sabotage scenarios in relation to spent fuel transport and storage casks, and associated risk assessments; the program also provides significant political benefits in international cooperation. We are quantifying the spent fuel ratio, SFR, the ratio of the aerosol particles released from HEDD-impacted actual spent fuel to the aerosol particles produced from surrogate materials, measured under closely matched test conditions. In addition, we are measuring the amounts, nuclide content, size distribution of the released aerosol materials, and enhanced sorption of volatile fission product nuclides onto specific aerosol particle size fractions. These data are crucial for predicting radiological impacts. This document includes a thorough description of the test program, including the current, detailed test plan, concept and design, plus a description of all test components, and requirements for future components and related nuclear facility needs. It also serves as a program status report as of the end of FY 2003. All available test results, observations, and analyses - primarily for surrogate material Phase 2 tests using cerium oxide sintered ceramic pellets are included. This spent fuel sabotage - aerosol test program is coordinated with the international Working Group for Sabotage Concerns of Transport and Storage Casks, WGSTSC, and supported by both the U.S. Department of Energy and Nuclear Regulatory Commission.

  2. Spent fuel sabotage aerosol ratio program : FY 2004 test and data summary.

    Energy Technology Data Exchange (ETDEWEB)

    Brucher, Wenzel (Gesellschaft fur Anlagen- und Reaktorsicherheit, Germany); Koch, Wolfgang (Fraunhofer Institut fur Toxikologie und Experimentelle Medizin, Germany); Pretzsch, Gunter Guido (Gesellschaft fur Anlagen- und Reaktorsicherheit, Germany); Loiseau, Olivier (Institut de Radioprotection et de Surete Nucleaire, France); Mo, Tin (U.S. Nuclear Regulatory Commission, Washington, DC); Billone, Michael C. (Argonne National Laboratory, Argonne, IL); Autrusson, Bruno A. (Institut de Radioprotection et de Surete Nucleaire, France); Young, F. I. (U.S. Nuclear Regulatory Commission, Washington, DC); Coats, Richard Lee; Burtseva, Tatiana (Argonne National Laboratory, Argonne, IL); Luna, Robert Earl; Dickey, Roy R.; Sorenson, Ken Bryce; Nolte, Oliver (Fraunhofer Institut fur Toxikologie und Experimentelle Medizin, Germany); Thompson, Nancy Slater (U.S. Department of Energy, Washington, DC); Hibbs, Russell S. (U.S. Department of Energy, Washington, DC); Gregson, Michael Warren; Lange, Florentin (Gesellschaft fur Anlagen- und Reaktorsicherheit, Germany); Molecke, Martin Alan; Tsai, Han-Chung (Argonne National Laboratory, Argonne, IL)

    2005-07-01

    This multinational, multi-phase spent fuel sabotage test program is quantifying the aerosol particles produced when the products of a high energy density device (HEDD) interact with and explosively particulate test rodlets that contain pellets of either surrogate materials or actual spent fuel. This program has been underway for several years. This program provides data that are relevant to some sabotage scenarios in relation to spent fuel transport and storage casks, and associated risk assessments. The program also provides significant technical and political benefits in international cooperation. We are quantifying the Spent Fuel Ratio (SFR), the ratio of the aerosol particles released from HEDD-impacted actual spent fuel to the aerosol particles produced from surrogate materials, measured under closely matched test conditions, in a contained test chamber. In addition, we are measuring the amounts, nuclide content, size distribution of the released aerosol materials, and enhanced sorption of volatile fission product nuclides onto specific aerosol particle size fractions. These data are the input for follow-on modeling studies to quantify respirable hazards, associated radiological risk assessments, vulnerability assessments, and potential cask physical protection design modifications. This document includes an updated description of the test program and test components for all work and plans made, or revised, during FY 2004. It also serves as a program status report as of the end of FY 2004. All available test results, observations, and aerosol analyses plus interpretations--primarily for surrogate material Phase 2 tests, series 2/5A through 2/9B, using cerium oxide sintered ceramic pellets are included. Advanced plans and progress are described for upcoming tests with unirradiated, depleted uranium oxide and actual spent fuel test rodlets. This spent fuel sabotage--aerosol test program is coordinated with the international Working Group for Sabotage Concerns of

  3. Deriving aerosol scattering ratio using range-resolved lidar ratio

    Indian Academy of Sciences (India)

    Reji K Dhaman; V Krishnakumar; V P Mahadevan Pillai; M Satyanarayana; K Raghunath

    2014-02-01

    The study on the optical characteristics of aerosol is carried out using the dual polarization lidar observations from the tropical inland station Gadanki (13.5°N, 79.2°E) for the period of observation during the year 2010. The summer and monsoon observation days show high scattering ratio at the tropical tropopause layer (TTL) and at the lower stratosphere region. The depolarization ratio is also high at this altitude due to the transport of particulates to the TTL layer by the active convection prevailing at the period. The study reveals more dependable values of scattering ratio that are seasonal and range-dependent.

  4. Retrieval of aerosol aspect ratio from optical measurements in Vienna

    Science.gov (United States)

    Kocifaj, M.; Horvath, H.; Gangl, M.

    The phase function and extinction coefficient measured simultaneously are interpreted in terms of surface distribution function and mean effective aspect ratio of aerosol particles. All optical data were collected in the atmosphere of Vienna during field campaign in June 2005. It is shown that behavior of aspect ratio of Viennese aerosols has relation to relative humidity in such a way, that nearly spherical particles (with aspect ratio ɛ≈1) might became aspherical with ɛ≈1.3-1.6 under low relative humidity conditions. Typically, >80% of all Viennese aerosols have the aspect ratio Vienna.

  5. TROPOSPHERIC AEROSOL PROGRAM, PROGRAM PLAN, MARCH 2001

    Energy Technology Data Exchange (ETDEWEB)

    SCHWARTZ,S.E.; LUNN,P.

    2001-03-01

    The goal of Tropospheric Aerosol Program (TAP) will be to develop the fundamental scientific understanding required to construct tools for simulating the life cycle of tropospheric aerosols--the processes controlling their mass loading, composition, and microphysical properties, all as a function of time, location, and altitude. The TAP approach to achieving this goal will be by conducting closely linked field, modeling, laboratory, and theoretical studies focused on the processes controlling formation, growth, transport, and deposition of tropospheric aerosols. This understanding will be represented in models suitable for describing these processes on a variety of geographical scales; evaluation of these models will be a key component of TAP field activities. In carrying out these tasks TAP will work closely with other programs in DOE and in other Federal and state agencies, and with the private sector. A forum to directly work with our counterparts in industry to ensure that the results of this research are translated into products that are useful to that community will be provided by NARSTO (formerly the North American Research Strategy on Tropospheric Ozone), a public/private partnership, whose membership spans government, the utilities, industry, and university researchers in Mexico, the US, and Canada.

  6. Aerosol measurement program strategy for global aerosol backscatter model development

    Science.gov (United States)

    Bowdle, David A.

    1985-01-01

    The purpose was to propose a balanced program of aerosol backscatter research leading to the development of a global model of aerosol backscatter. Such a model is needed for feasibility studies and systems simulation studies for NASA's prospective satellite-based Doppler lidar wind measurement system. Systems of this kind measure the Doppler shift in the backscatter return from small atmospheric aerosol wind tracers (of order 1 micrometer diameter). The accuracy of the derived local wind estimates and the degree of global wind coverage for such a system are limited by the local availability and by the global scale distribution of natural aerosol particles. The discussions here refer primarily to backscatter model requirements at CO2 wavelengths, which have been selected for most of the Doppler lidar systems studies to date. Model requirements for other potential wavelengths would be similar.

  7. Accurate and precise zinc isotope ratio measurements in urban aerosols.

    Science.gov (United States)

    Gioia, Simone; Weiss, Dominik; Coles, Barry; Arnold, Tim; Babinski, Marly

    2008-12-15

    We developed an analytical method and constrained procedural boundary conditions that enable accurate and precise Zn isotope ratio measurements in urban aerosols. We also demonstrate the potential of this new isotope system for air pollutant source tracing. The procedural blank is around 5 ng and significantly lower than published methods due to a tailored ion chromatographic separation. Accurate mass bias correction using external correction with Cu is limited to Zn sample content of approximately 50 ng due to the combined effect of blank contribution of Cu and Zn from the ion exchange procedure and the need to maintain a Cu/Zn ratio of approximately 1. Mass bias is corrected for by applying the common analyte internal standardization method approach. Comparison with other mass bias correction methods demonstrates the accuracy of the method. The average precision of delta(66)Zn determinations in aerosols is around 0.05 per thousand per atomic mass unit. The method was tested on aerosols collected in Sao Paulo City, Brazil. The measurements reveal significant variations in delta(66)Zn(Imperial) ranging between -0.96 and -0.37 per thousand in coarse and between -1.04 and 0.02 per thousand in fine particular matter. This variability suggests that Zn isotopic compositions distinguish atmospheric sources. The isotopic light signature suggests traffic as the main source. We present further delta(66)Zn(Imperial) data for the standard reference material NIST SRM 2783 (delta(66)Zn(Imperial) = 0.26 +/- 0.10 per thousand).

  8. Retrieving the aerosol lidar ratio profile by combining ground- and space-based elastic lidars.

    Science.gov (United States)

    Feiyue, Mao; Wei, Gong; Yingying, Ma

    2012-02-15

    The aerosol lidar ratio is a key parameter for the retrieval of aerosol optical properties from elastic lidar, which changes largely for aerosols with different chemical and physical properties. We proposed a method for retrieving the aerosol lidar ratio profile by combining simultaneous ground- and space-based elastic lidars. The method was tested by a simulated case and a real case at 532 nm wavelength. The results demonstrated that our method is robust and can obtain accurate lidar ratio and extinction coefficient profiles. Our method can be useful for determining the local and global lidar ratio and validating space-based lidar datasets.

  9. Investigate the relationship between multiwavelength lidar ratios and aerosol size distributions using aerodynamic particle sizer spectrometer

    Science.gov (United States)

    Zhao, Hu; Hua, Dengxin; Mao, Jiandong; Zhou, Chunyan

    2017-02-01

    The real aerosol size distributions were obtained by aerodynamic particle sizer spectrometer (APS) in China YinChuan. The lidar ratios at wavelengths of 355 nm, 532 nm and 1064 nm were calculated using Mie theory. The effective radius of aerosol particles reff and volume C/F ratio (coarse/fine) Vc/f were retrieved from the real aerosol size distributions. The relationship between multiwavelength lidar ratios and particle reff and Vc/f were investigated. The results indicate that the lidar ratio is positive correlated to the particle reff and Vc/f. The lidar ratio is more sensitive to the coarse particles. The short wavelength lidar ratio is more sensitive to the particle Vc/f and the long wavelength lidar ratio is more sensitive to the particle reff. The wavelength dependency indicated that the lidar ratios decrease with increasing the wavelength. The lidar ratios are almost irrelevant to the shape and total particles of aerosol size distributions.

  10. Spent fuel sabotage aerosol test program :FY 2005-06 testing and aerosol data summary.

    Energy Technology Data Exchange (ETDEWEB)

    Gregson, Michael Warren; Brockmann, John E.; Nolte, O. (Fraunhofer institut fur toxikologie und experimentelle Medizin, Germany); Loiseau, O. (Institut de radioprotection et de Surete Nucleaire, France); Koch, W. (Fraunhofer institut fur toxikologie und experimentelle Medizin, Germany); Molecke, Martin Alan; Autrusson, Bruno (Institut de radioprotection et de Surete Nucleaire, France); Pretzsch, Gunter Guido (Gesellschaft fur anlagen- und Reaktorsicherheit, Germany); Billone, M. C. (Argonne National Laboratory, USA); Lucero, Daniel A.; Burtseva, T. (Argonne National Laboratory, USA); Brucher, W (Gesellschaft fur anlagen- und Reaktorsicherheit, Germany); Steyskal, Michele D.

    2006-10-01

    This multinational, multi-phase spent fuel sabotage test program is quantifying the aerosol particles produced when the products of a high energy density device (HEDD) interact with and explosively particulate test rodlets that contain pellets of either surrogate materials or actual spent fuel. This program has been underway for several years. This program provides source-term data that are relevant to some sabotage scenarios in relation to spent fuel transport and storage casks, and associated risk assessments. This document focuses on an updated description of the test program and test components for all work and plans made, or revised, primarily during FY 2005 and about the first two-thirds of FY 2006. It also serves as a program status report as of the end of May 2006. We provide details on the significant findings on aerosol results and observations from the recently completed Phase 2 surrogate material tests using cerium oxide ceramic pellets in test rodlets plus non-radioactive fission product dopants. Results include: respirable fractions produced; amounts, nuclide content, and produced particle size distributions and morphology; status on determination of the spent fuel ratio, SFR (the ratio of respirable particles from real spent fuel/respirables from surrogate spent fuel, measured under closely matched test conditions, in a contained test chamber); and, measurements of enhanced volatile fission product species sorption onto respirable particles. We discuss progress and results for the first three, recently performed Phase 3 tests using depleted uranium oxide, DUO{sub 2}, test rodlets. We will also review the status of preparations and the final Phase 4 tests in this program, using short rodlets containing actual spent fuel from U.S. PWR reactors, with both high- and lower-burnup fuel. These data plus testing results and design are tailored to support and guide, follow-on computer modeling of aerosol dispersal hazards and radiological consequence

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

    Science.gov (United States)

    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

  12. Surrogate/spent fuel sabotage aerosol ratio testing:phase 1 summary and results.

    Energy Technology Data Exchange (ETDEWEB)

    Vigil, Manuel Gilbert; Sorenson, Ken Bryce; Lange, F. (Gesellschaft fur Anlagen- und reaktorsicherheit (GRS), Germany); Nolte, O. (Fraunhofer Institut fur Toxikologie und Experimentelle Medizin, Germany); Koch, W. (Fraunhofer Institut fur Toxikologie und Experimentelle Medizin, Germany); Dickey, Roy R.; Yoshimura, Richard Hiroyuki; Molecke, Martin Alan; Autrusson, Bruno (Institut de Radioprotection et de Surete Nucleaire (IRSN), France); Young, F. I. (U.S. Nuclear Regulatory Commission); Pretzsch, Gunter Guido (Gesellschaft fur Anlagen- und reaktorsicherheit (GRS), Germany)

    2005-10-01

    This multinational test program is quantifying the aerosol particulates produced when a high energy density device (HEDD) impacts surrogate material and actual spent fuel test rodlets. The experimental work, performed in four consecutive test phases, has been in progress for several years. The overall program provides needed data that are relevant to some sabotage scenarios in relation to spent fuel transport and storage casks, and associated risk assessments. This program also provides significant political benefits in international cooperation for nuclear security related evaluations. The spent fuel sabotage--aerosol test program is coordinated with the international Working Group for Sabotage Concerns of Transport and Storage Casks (WGSTSC), and supported by both the U.S. Department of Energy and Nuclear Regulatory Commission. This report summarizes the preliminary, Phase 1 work performed in 2001 and 2002 at Sandia National Laboratories and the Fraunhofer Institute, Germany, and documents the experimental results obtained, observations, and preliminary interpretations. Phase 1 testing included: performance quantifications of the HEDD devices; characterization of the HEDD or conical shaped charge (CSC) jet properties with multiple tests; refinement of the aerosol particle collection apparatus being used; and, CSC jet-aerosol tests using leaded glass plates and glass pellets, serving as representative brittle materials. Phase 1 testing was quite important for the design and performance of the following Phase 2 test program and test apparatus.

  13. Aerosol organic carbon to black carbon ratios: Analysis ofpublished data and implications for climate forcing

    Energy Technology Data Exchange (ETDEWEB)

    Novakov, T.; Menon, S.; Kirchstetter, T.W.; Koch, D.; Hansen, J.E.

    2005-07-11

    Measurements of organic carbon (OC) and black carbon (BC)concentrations over a variety of locations worldwide, have been analyzed to infer the spatial distributions of the ratios of OC to BC. Since these ratios determine the relative amounts of scattering and absorption, they are often used to estimate the radiative forcing due to aerosols. An artifact in the protocol for filter measurements of OC has led to widespread overestimates of the ratio of OC to BC in atmospheric aerosols. We developed a criterion to correct for this artifact and analyze corrected OC to BC ratios. The OC to BC ratios, ranging from 1.3to 2.4, appear relatively constant and are generally unaffected by seasonality, sources or technology changes, at the locations considered here. The ratios compare well with emission inventories over Europe and China but are a factor of two lower in other regions. The reduced estimate for OC/BC in aerosols strengthens the argument that reduction of soot emissions maybe a useful approach to slow global warming.

  14. On Quadratic Programming with a Ratio Objective

    CERN Document Server

    Bhaskara, Aditya; Manokaran, Rajsekar; Vijayaraghavan, Aravindan

    2011-01-01

    Quadratic Programming (QP) is the well-studied problem of maximizing over {-1,1} values the quadratic form \\sum_ij a_ij x_i x_j. QP captures many known combinatorial optimization problems and SDP techniques have given optimal approximation algorithms for many of these problems. We extend this body of work by initiating the study of Quadratic Programming problems where the variables take values in the domain {-1,0,1}. The specific problem we study is: QP-Ratio: max_{-1,0,1}^n (x^T A x) / (x^T x). This objective function is a natural relative of several well studied problems. Yet, it is a good testbed for both algorithms and complexity because the techniques used for quadratic problems for the {-1,1} and {0,1} domains do not seem to carry over to the {-1,0,1} domain. We give approximation algorithms and evidence for the hardness of approximating the QP-Ratio problem. We consider an SDP relaxation obtained by adding constraints to the natural SDP relaxation for this problem and obtain an O(n^{2/7}) algorithm for...

  15. Spent fuel sabotage test program, characterization of aerosol dispersal : interim final report.

    Energy Technology Data Exchange (ETDEWEB)

    Gregson, Michael Warren; Brockmann, John E.; Loiseau, Olivier (Institut de Radioprotection et de Surete Nucleaire, France); Klennert, Lindsay A.; Nolte, Oliver (Fraunhofer Institut fur Toxikologie und Experimentelle Medizin, Germany); Molecke, Martin Alan; Autrusson, Bruno A. (Institut de Radioprotection et de Surete Nucleaire, France); Koch, Wolfgang (Fraunhofer Institut fur Toxikologie und Experimentelle Medizin, Germany); Pretzsch, Gunter Guido (Gesellschaft fur Anlagen- und Reaktorsicherheit, Germany); Brucher, Wenzel (Gesellschaft fur Anlagen- und Reaktorsicherheit, Germany); Steyskal, Michele D.

    2008-03-01

    This multinational, multi-phase spent fuel sabotage test program is quantifying the aerosol particles produced when the products of a high energy density device (HEDD) interact with and explosively particulate test rodlets that contain pellets of either surrogate materials or actual spent fuel. This program provides source-term data that are relevant to plausible sabotage scenarios in relation to spent fuel transport and storage casks and associated risk assessments. We present details and significant results obtained from this program from 2001 through 2007. Measured aerosol results include: respirable fractions produced; amounts, nuclide content, and produced particle size distributions and morphology; measurements of volatile fission product species enhanced sorption--enrichment factors onto respirable particles; and, status on determination of the spent fuel ratio, SFR, needed for scaling studies. Emphasis is provided on recent Phase 3 tests using depleted uranium oxide pellets plus non-radioactive fission product dopants in surrogate spent fuel test rodlets, plus the latest surrogate cerium oxide results and aerosol laboratory supporting calibration work. The DUO{sub 2}, CeO{sub 2}, plus fission product dopant aerosol particle results are compared with available historical data. We also provide a status review on continuing preparations for the final Phase 4 in this program, tests using individual short rodlets containing actual spent fuel from U.S. PWR reactors, with both high- and lower-burnup fuel. The source-term data, aerosol results, and program design have been tailored to support and guide follow-on computer modeling of aerosol dispersal hazards and radiological consequence assessments. This spent fuel sabotage, aerosol test program was performed primarily at Sandia National Laboratories, with support provided by both the U.S. Department of Energy and the Nuclear Regulatory Commission. This program has significant input from, and is cooperatively

  16. Size specific indoor aerosol deposition measurements and derived I/O concentrations ratios

    DEFF Research Database (Denmark)

    Fogh, C.L.; Byrne, M.A.; Roed, Jørn;

    1997-01-01

    The process of aerosol deposition on indoor surfaces has implications for human exposure to particulate contaminants of both indoor and outdoor origin. In the radiological context, current accident models assume a uniform Dose Reduction Factor (DRF) of 0.5 for indoor residence during the outdoor...... and dispersed in unfurnished and furnished rooms; the decay rate of the particles was then inferred from analysis of sequential air samples. Allowing for the differences in furnishing and level of occupancy between the tests, consistent aerosol deposition velocities were determined and, for furnished rooms...... with previous measurements of I/O ratios for fine and coarse particles. It was concluded that, for realistic dose estimates, a radioisotope-specific factor may be merited. (C) 1997 Elsevier Science Ltd....

  17. Biases in modeled surface snow BC mixing ratios in prescribed aerosol climate model runs

    OpenAIRE

    Doherty, S. J.; C. M. Bitz; M. G. Flanner

    2014-01-01

    A series of recent studies have used prescribed aerosol deposition flux fields in climate model runs to assess forcing by black carbon in snow. In these studies, the prescribed mass deposition flux of BC to surface snow is decoupled from the mass deposition flux of snow water to the surface. Here we use a series of offline calculations to show that this approach results, on average, in a~factor of about 1.5–2.5 high bias in annual-mean surface snow BC mixing ratios in three ...

  18. Pilot Study of Inhaled Aerosols Targeted via Magnetic Alignment of High Aspect Ratio Particles in Rabbits

    Directory of Open Access Journals (Sweden)

    Gillian E. S. Redman

    2011-01-01

    Full Text Available Recently, inhaled pharmaceutical aerosols have seen increased investigation in the treatment of lung cancer, where the inability to deliver adequate therapeutic drug concentrations to tumour sites may be overcome with improved targeted delivery to the site of the tumour. In this study, the feasibility of magnetically targeted delivery of high aspect ratio particles loaded with iron oxide nanoparticles was studied in 19 New Zealand White rabbits. Half of the exposed rabbits had a magnetic field placed externally over their right lung. Iron sensitive magnetic resonance images of the lungs were acquired to determine the iron concentrations in the right and left lung of each animal. The right/left ratio increased in the middle and basal regions of the lung where, due to the morphology of the rabbit lung, this method of targeting is most effective. With further optimization, this technique could be an effective method for increasing the dose of drug delivered to a specific site within the lung.

  19. Stable carbon isotope ratios of ambient secondary organic aerosols in Toronto

    Science.gov (United States)

    Saccon, M.; Kornilova, A.; Huang, L.; Moukhtar, S.; Rudolph, J.

    2015-09-01

    A method to quantify concentrations and stable carbon isotope ratios of secondary organic aerosols has been applied to study atmospheric nitrophenols in Toronto, Canada. The sampling of five nitrophenols, all with substantial secondary formation from the photooxidation of aromatic volatile organic compounds (VOCs), was conducted in the gas phase and particulate matter (PM) together and in PM alone. Their concentrations in the atmosphere are in the low ng m-3 range and, consequently, a large volume of air (> 1000 m3) is needed to analyze samples for stable carbon isotope ratios, resulting in sampling periods of typically 24 h. While this extended sampling period increases the representativeness of average values, it at the same time reduces possibilities to identify meteorological conditions or atmospheric pollution levels determining nitrophenol concentrations and isotope ratios. Average measured carbon isotope ratios of the different nitrophenols are between -34 and -33 ‰, which is well within the range predicted by mass balance. However, the observed carbon isotope ratios cover a range of nearly 9 ‰ and approximately 20 % of the isotope ratios of the products have isotope ratios lower than predicted from the kinetic isotope effect of the first step of the reaction mechanism and the isotope ratio of the precursor. This can be explained by isotope fractionation during reaction steps following the initial reaction of the precursor VOCs with the OH radical. Limited evidence for local production of nitrophenols is observed since sampling was done in the Toronto area, an urban center with significant anthropogenic emission sources. Strong evidence for significant local formation of nitrophenols is only found for samples collected in summer. On average, the difference in carbon isotope ratios between nitrophenols in the particle phase and in the gas phase is insignificant, but for a limited number of observations in summer, a substantial difference is observed. This

  20. Use of stable carbon and nitrogen isotope ratios in size segregated aerosol particles for the O/I penetration evaluation

    Science.gov (United States)

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

    2015-04-01

    Stable carbon and nitrogen isotope ratio are successfully used in the atmospheric aerosol particle source identification [1, 2], transformation, pollution [3] research. The main purpose of this study was to evaluate the penetration of atmospheric aerosol particles from outdoor to indoor using stable carbon and nitrogen isotope ratios. Six houses in Kaunas (Lithuania) were investigated during February and March 2013. Electrical low pressure impactor was used to measure in real time concentration and size distribution of outdoor aerosol particles. ELPI+ includes 15 channels covering the size range from 0.017 to 10.0 µm. The 25 mm diameter aluminium foils were used to collect aerosol particles. Gravimetric analysis of samples was made using microbalance. In parallel, indoor aerosol samples were collected with a micro-orifice uniform deposition impactor (MOUDI model 110), where the aerosol particles were separated with the nominal D50 cut-off sizes of 0.056, 0.1, 0.18,0.32,0.56, 1.0, 1.8, 3.2, 5.6, 10, 18 μm for impactor stages 1-11, respectively. The impactor was run at a flow rate of 30 L/min. Air quality meters were used to record meteorological conditions (temperature, relative humidity) during the investigated period. All aerosol samples were analyzed for total carbon (TC) and total nitrogen (TN) contents and their isotopic compositions using elemental analyzer (EA) connected to the stable isotope ratio mass spectrometer (IRMS). TC concentration in indoors ranged from 1.5 to 247.5 µg/m3. During the sampling period outdoors TN levels ranged from 0.1 to 10.9 µg/m3. The obtained outdoor δ13C(PM2.5) values varied from -24.21 to -26.3‰, while the δ15N values varied from 2.4 to 11.1 ‰ (average 7.2±2.5 ‰). Indoors carbonaceous aerosol particles were depleted in 13C compared to outdoors in all sampling sites. This depletion in δ13C varied from 0.1 to 3.2 ‰. We think that this depletion occurs due ongoing chemical reactions (oxidation) when aerosol

  1. Dependence of the spectral diffuse-direct irradiance ratio on aerosol spectral distribution and single scattering albedo

    Science.gov (United States)

    Kaskaoutis, D. G.; Kambezidis, H. D.; Dumka, U. C.; Psiloglou, B. E.

    2016-09-01

    This study investigates the modification of the clear-sky spectral diffuse-direct irradiance ratio (DDR) as a function of solar zenith angle (SZA), spectral aerosol optical depth (AOD) and single scattering albedo (SSA). The solar spectrum under various atmospheric conditions is derived with Simple Model of the Atmospheric Radiative Transfer of Sunshine (SMARTS) radiative transfer code, using the urban and continental aerosol models as inputs. The spectral DDR can be simulated with great accuracy by an exponentially decreasing curve, while the aerosol optical properties strongly affect the scattering processes in the atmosphere, thus modifying the DDR especially in the ultraviolet (UV) spectrum. Furthermore, the correlation between spectral DDR and spectral AOD can be represented precisely by an exponential function and can give valuable information about the dominance of specific aerosol types. The influence of aerosols on spectral DDR increases with increasing SZA, while the simulations using the urban aerosol model as input in SMARTS are closer to the measurements taken in the Athens urban environment. The SMARTS simulations are interrelated with spectral measurements and can be used for indirect estimations of SSA. Overall, the current work provides some theoretical approximations and functions that help in understanding the dependence of DDR on astronomical and atmospheric parameters.

  2. Behavior of zonal mean aerosol extinction ratio and its relationship with zonal mean temperature during the winter 1978-1979 stratospheric warming

    Science.gov (United States)

    Wang, P.-H.; Mccormick, M. P.

    1985-01-01

    The behavior of the zonal mean aerosol extinction ratio in the lower stratosphere near 75 deg N and its relationship with the zonal mean temperature during the January-February 1979 stratospheric sudden warming have been investigated based on the satellite sensor SAM II (Stratospheric Aerosol Measurement) and auxiliary meteorological measurements. The results indicate that distinct changes in the zonal mean aerosol extinction ratio occurred during this stratospheric sudden warming. It is also found that horizontal eddy transport due to planetary waves may have played a significant role in determining the distribution of the zonal mean aerosol extinction ratio.

  3. Observations of the spectral dependence of linear particle depolarization ratio of aerosols using NASA Langley airborne High Spectral Resolution Lidar

    Science.gov (United States)

    Burton, S. P.; Hair, J. W.; Kahnert, M.; Ferrare, R. A.; Hostetler, C. A.; Cook, A. L.; Harper, D. B.; Berkoff, T. A.; Seaman, S. T.; Collins, J. E.; Fenn, M. A.; Rogers, R. R.

    2015-12-01

    Linear particle depolarization ratio is presented for three case studies from the NASA Langley airborne High Spectral Resolution Lidar-2 HSRL-2). Particle depolarization ratio from lidar is an indicator of non-spherical particles and is sensitive to the fraction of non-spherical particles and their size. The HSRL-2 instrument measures depolarization at three wavelengths: 355, 532, and 1064 nm. The three measurement cases presented here include two cases of dust-dominated aerosol and one case of smoke aerosol. These cases have partial analogs in earlier HSRL-1 depolarization measurements at 532 and 1064 nm and in literature, but the availability of three wavelengths gives additional insight into different scenarios for non-spherical particles in the atmosphere. A case of transported Saharan dust has a spectral dependence with a peak of 0.30 at 532 nm with smaller particle depolarization ratios of 0.27 and 0.25 at 1064 and 355 nm, respectively. A case of aerosol containing locally generated wind-blown North American dust has a maximum of 0.38 at 1064 nm, decreasing to 0.37 and 0.24 at 532 and 355 nm, respectively. The cause of the maximum at 1064 nm is inferred to be very large particles that have not settled out of the dust layer. The smoke layer has the opposite spectral dependence, with the peak of 0.24 at 355 nm, decreasing to 0.09 and 0.02 at 532 and 1064 nm, respectively. The depolarization in the smoke case may be explained by the presence of coated soot aggregates. We note that in these specific case studies, the linear particle depolarization ratio for smoke and dust-dominated aerosol are more similar at 355 nm than at 532 nm, having possible implications for using the particle depolarization ratio at a single wavelength for aerosol typing.

  4. Saharan and Arabian Dust Aerosols: A Comparative Case Study of Lidar Ratio

    Directory of Open Access Journals (Sweden)

    Córdoba-Jabonero Carmen

    2016-01-01

    Full Text Available This work presents a first comparative study of the Lidar Ratio (LR values obtained for dust particles in two singular dust-influenced regions: the Canary Islands (Spain, close to the African coast in the North Atlantic Ocean, frequently affected by Saharan dust intrusions, and the Kuwait area (Arabian Peninsula as usually influenced by Arabian dust storms. Synergetic lidar and sun-photometry measurements are carried out in two stations located in these particular regions for that purpose. Several dusty cases were observed during 2014 in both stations and, just for illustration, two specific dusty case studies have been selected and analyzed to be shown in this work. In general, mean LR values of 54 sr and 40 sr were obtained in these studies cases for Saharan and Arabian dust particles, respectively. Indeed, these results are in agreement with other studies performed for dust particles arriving from similar desert areas. In particular, the disparity found in Saharan and Arabian dust LR values can be based on the singular composition of the suspended dust aerosols over each station. These results can be useful for CALIPSO extinction retrievals, where a single LR value (40 sr is assumed for pure dust particles independently on the dust source region.

  5. Effectiveness of leaded petrol phase-out in Tianjin, China based on the aerosol lead concentration and isotope abundance ratio

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wan [Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Liu Xiande [Chinese Research Academy of Environmental Sciences, Beijing 100012 (China)]. E-mail: liuxdlxd@hotmail.com; Zhao Liwei [Tianjin Environmental Monitoring Center, Tianjin, 300190 (China); Guo, Dongfa [Beijing Research Institute of Uranium Geology, Beijing 100029 (China); Tian Xiaodan [University of Antwerp, UA, B-2610 Wilrijk-Antwerpen (Belgium); Adams, Freddy [University of Antwerp, UA, B-2610 Wilrijk-Antwerpen (Belgium)

    2006-07-01

    The phase-out of leaded petrol has been a measure widely used to reduce atmospheric lead pollution. Since the 1980s, China began to promote unleaded petrol. In order to assess the effectiveness of the measure an isotope fingerprint technique was applied for aerosol samples in the city of Tianjin. After dilute acid leaching, the lead concentration and isotope abundance ratios were determined for 123 samples collected in Tianjin during eight years (1994-2001). The {sup 206}Pb / {sup 207}Pb ratio was lower in summer, when coal combustion emission was low and vehicle exhaust became more important, indicating that the {sup 206}Pb / {sup 207}Pb ratio of leaded petrol in Tianjin is lower than that of aerosol samples. The {sup 206}Pb / {sup 207}Pb ratio gradually increased from 1994 to 2001, a trend that suggests that the contribution from vehicle exhaust was diminishing. Overall, the measurements matched well with national statistical data of leaded and unleaded petrol production. After the nationwide switch to unleaded gasoline, comprehensive control measures are urgently needed to reduce air lead pollution in China, as aerosol lead reduced slightly but remains at a relatively high level.

  6. Effectiveness of leaded petrol phase-out in Tianjin, China based on the aerosol lead concentration and isotope abundance ratio

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wan; Liu, Xiande [Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Zhao, Liwei [Tianjin Environmental Monitoring Center, Tianjin, 300190 (China); Guo, Dongfa [Beijing Research Institute of Uranium Geology, Beijing 100029 (China); Tian, Xiaodan; Adams, Freddy [University of Antwerp, UA, B-2610 Wilrijk-Antwerpen (Belgium)

    2006-07-01

    The phase-out of leaded petrol has been a measure widely used to reduce atmospheric lead pollution. Since the 1980s, China began to promote unleaded petrol. In order to assess the effectiveness of the measure an isotope fingerprint technique was applied for aerosol samples in the city of Tianjin. After dilute acid leaching, the lead concentration and isotope abundance ratios were determined for 123 samples collected in Tianjin during eight years (1994-2001). The {sup 206}Pb/{sup 207}Pb ratio was lower in summer, when coal combustion emission was low and vehicle exhaust became more important, indicating that the {sup 206}Pb/{sup 207}Pb ratio of leaded petrol in Tianjin is lower than that of aerosol samples. The {sup 206}Pb/{sup 207}Pb ratio gradually increased from 1994 to 2001, a trend that suggests that the contribution from vehicle exhaust was diminishing. Overall, the measurements matched well with national statistical data of leaded and unleaded petrol production. After the nationwide switch to unleaded gasoline, comprehensive control measures are urgently needed to reduce air lead pollution in China, as aerosol lead reduced slightly but remains at a relatively high level. (author)

  7. Insights Into Water-Soluble Organic Aerosol Sources From Carbon-13 Ratios of Size Exclusion Chromatography Fractions

    Science.gov (United States)

    Ruehl, C. R.; Chuang, P. Y.; McCarthy, M. D.

    2008-12-01

    Many sources of organic aerosols have been identified and quantified, and much of this work has used individual (mosty water-insoluble) compounds as tracers of primary sources. However, most organic aerosol cannot be molecularly characterized, and the water-soluble organic carbon (WSOC) in many aerosols is thought to originate from gaseous precursors (i.e., it is secondary in nature). It can therefore be difficult to infer aerosol sources, particularly of background (i.e., aged) aerosols, and of the relatively high-MW component of aerosols. The stable isotope ratios (δ13C) of organic aerosols have been used to distinguish between sources, with lighter values (-30‰ to -25‰) interpreted as having originated from fossil fuel combustion and C4 biogenic emission, and heavier values (-25‰ to - 20‰) indicating a marine or C3 biogenic source. Most published measurements were of either total suspended particulates or PM2.5, however, and it is unknown to what extent these fractions differ from submicron WSOC. We report δ13C for submicron WSOC collected at a variety of sites, ranging from marine to polluted to background continental. Bulk marine organic δ13C ranged from -30.4 to - 27.6‰, slightly lighter than previously published results. This could be due to the elimination of supermicron cellular material or other biogenic primary emissions from the sample. Continental WSOC δ13C ranged from -19.1 to -29.8‰, with heavier values (-19.8 ± 1.0‰) in Oklahoma and lighter values at Great Smoky Mountain National Park in Tennessee (-25.8 ± 2.6‰) and Illinois (-24.5 ± 1.0‰). This likely results from the greater proportional of C3 plant material in the Oklahoma samples. In addition to bulk samples, we used size exclusion chromatography (SEC) to report δ13C of organic aerosols as a function of hydrodynamic diameter. Variability and magnitude of hydrodynamic diameter was greatest at low SEC pH, indicative of the acidic character of submicron WSOC. Tennessee

  8. 我国城市大气颗粒物的铅同位素丰度比%Lead Isotope Abundance Ratios of Urban Atmospheric Aerosols in China

    Institute of Scientific and Technical Information of China (English)

    刘咸德; 李显芳; 李冰

    2004-01-01

    Determined with ICP-MS, new isotope abundance ratio data of lead for Beijing and Changdao aerosols was presented, in comparison with literature data for Chinese urban aerosols. 206Pb/207Pb ratio falls into a range from 1.13 to 1.18 for urban aerosols and less influenced by vehicle exhaust emission after phase-out of leaded petrol in 2000 in China. Major lead pollution sources may probably include coal combustion, oil combustion,re-suspended dust, metallurgical industry and use and production of cement.

  9. Biases in modeled surface snow BC mixing ratios in prescribed-aerosol climate model runs

    OpenAIRE

    Doherty, S. J.; C. M. Bitz; M. G. Flanner

    2014-01-01

    Black carbon (BC) in snow lowers its albedo, increasing the absorption of sunlight, leading to positive radiative forcing, climate warming and earlier snowmelt. A series of recent studies have used prescribed-aerosol deposition flux fields in climate model runs to assess the forcing by black carbon in snow. In these studies, the prescribed mass deposition flux of BC to surface snow is decoupled from the mass deposition flux of snow water to the surface. Here we compare progn...

  10. An enhanced VIIRS aerosol optical thickness (AOT) retrieval algorithm over land using a global surface reflectance ratio database

    Science.gov (United States)

    Zhang, Hai; Kondragunta, Shobha; Laszlo, Istvan; Liu, Hongqing; Remer, Lorraine A.; Huang, Jingfeng; Superczynski, Stephen; Ciren, Pubu

    2016-09-01

    The Visible/Infrared Imager Radiometer Suite (VIIRS) on board the Suomi National Polar-orbiting Partnership (S-NPP) satellite has been retrieving aerosol optical thickness (AOT), operationally and globally, over ocean and land since shortly after S-NPP launch in 2011. However, the current operational VIIRS AOT retrieval algorithm over land has two limitations in its assumptions for land surfaces: (1) it only retrieves AOT over the dark surfaces and (2) it assumes that the global surface reflectance ratios between VIIRS bands are constants. In this work, we develop a surface reflectance ratio database over land with a spatial resolution 0.1° × 0.1° using 2 years of VIIRS top of atmosphere reflectances. We enhance the current operational VIIRS AOT retrieval algorithm by applying the surface reflectance ratio database in the algorithm. The enhanced algorithm is able to retrieve AOT over both dark and bright surfaces. Over bright surfaces, the VIIRS AOT retrievals from the enhanced algorithm have a correlation of 0.79, mean bias of -0.008, and standard deviation (STD) of error of 0.139 when compared against the ground-based observations at the global AERONET (Aerosol Robotic Network) sites. Over dark surfaces, the VIIRS AOT retrievals using the surface reflectance ratio database improve the root-mean-square error from 0.150 to 0.123. The use of the surface reflectance ratio database also increases the data coverage of more than 20% over dark surfaces. The AOT retrievals over bright surfaces are comparable to MODIS Deep Blue AOT retrievals.

  11. Lidar Ratios for Dust Aerosols Derived From Retrievals of CALIPSO Visible Extinction Profiles Constrained by Optical Depths from MODIS-Aqua and CALIPSO/CloudSat Ocean Surface Reflectance Measurements

    Science.gov (United States)

    Young, Stuart A.; Josset, Damien B.; Vaughan, Mark A.

    2010-01-01

    CALIPSO's (Cloud Aerosol Lidar Infrared Pathfinder Satellite Observations) analysis algorithms generally require the use of tabulated values of the lidar ratio in order to retrieve aerosol extinction and optical depth from measured profiles of attenuated backscatter. However, for any given time or location, the lidar ratio for a given aerosol type can differ from the tabulated value. To gain some insight as to the extent of the variability, we here calculate the lidar ratio for dust aerosols using aerosol optical depth constraints from two sources. Daytime measurements are constrained using Level 2, Collection 5, 550-nm aerosol optical depth measurements made over the ocean by the MODIS (Moderate Resolution Imaging Spectroradiometer) on board the Aqua satellite, which flies in formation with CALIPSO. We also retrieve lidar ratios from night-time profiles constrained by aerosol column optical depths obtained by analysis of CALIPSO and CloudSat backscatter signals from the ocean surface.

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

    Science.gov (United States)

    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 ...

  13. The Capra Research Program for Modelling Extreme Mass Ratio Inspirals

    CERN Document Server

    Thornburg, Jonathan

    2011-01-01

    Suppose a small compact object (black hole or neutron star) of mass $m$ orbits a large black hole of mass $M \\gg m$. This system emits gravitational waves (GWs) that have a radiation-reaction effect on the particle's motion. EMRIs (extreme--mass-ratio inspirals) of this type will be important GW sources for LISA; LISA's data analysis will require highly accurate EMRI GW templates. In this article I outline the "Capra" research program to try to model EMRIs and calculate their GWs \\textit{ab initio}, assuming only that $m \\ll M$ and that the Einstein equations hold. Here we treat the EMRI spacetime as a perturbation of the large black hole's "background" (Schwarzschild or Kerr) spacetime and use the methods of black-hole perturbation theory, expanding in the small parameter $m/M$. The small body's motion can be described either as the result of a radiation-reaction "self-force" acting in the background spacetime or as geodesic motion in a perturbed spacetime. Several different lines of reasoning lead to the (s...

  14. Seasonal variations of stable carbon isotopic ratios and biogenic tracer compounds of water-soluble organic aerosols in a deciduous forest

    Directory of Open Access Journals (Sweden)

    Y. Miyazaki

    2011-11-01

    Full Text Available To investigate the seasonal changes in biogenic water-soluble organic carbon (WSOC aerosols in a boreal forest, aerosol samples were collected continuously in the canopy of a~deciduous forest in Northern Japan during 2009–2010. Stable carbon isotopic ratios of WSOC (δ13CWSOC in aerosols exhibited a distinct seasonal cycle, with lower values from June through September (−25.5 ± 0.5‰. This cycle follows the net CO2 exchange between the forest ecosystem and the atmosphere, indicating that δ13CWSOC likely reflects the biological activity at the forest site. WSOC concentrations showed the highest values in early summer and autumn. Positive matrix factorization (PMF analysis indicated that the factor in which biogenic secondary organic aerosols (BSOAs dominated accounted for ~ 40% of the highest concentrations of WSOC, where BSOAs mostly consisted of α-/β-pinene SOA. In addition, primary biological aerosol particles (PBAPs made similar contributions (~ 57% to the WSOC near the canopy floor in early summer. This finding indicates that the production of both primary and secondary WSOC aerosols is important during the growing season in a deciduous forest. The methanesulfonic acid (MSA maximum was also found in early summer and had a distinct vertical gradient with larger concentrations near the canopy floor. Together with the similar vertical gradients found for WSOC and δ13CWSOCas well as the α-/β-pinene SOA tracers, our results indicate that the forest floor, including ground vegetation and soil, acts as a significant source of the WSOC within a~forest canopy at the study site.

  15. The Capra Research Program for Modelling Extreme Mass Ratio Inspirals

    Science.gov (United States)

    Thornburg, Jonathan

    2011-02-01

    Suppose a small compact object (black hole or neutron star) of mass m orbits a large black hole of mass M ≫ m. This system emits gravitational waves (GWs) that have a radiation-reaction effect on the particle's motion. EMRIs (extreme-mass-ratio inspirals) of this type will be important GW sources for LISA. To fully analyze these GWs, and to detect weaker sources also present in the LISA data stream, will require highly accurate EMRI GW templates. In this article I outline the ``Capra'' research program to try to model EMRIs and calculate their GWs ab initio, assuming only that m ≪ M and that the Einstein equations hold. Because m ≪ M the timescale for the particle's orbit to shrink is too long for a practical direct numerical integration of the Einstein equations, and because this orbit may be deep in the large black hole's strong-field region, a post-Newtonian approximation would be inaccurate. Instead, we treat the EMRI spacetime as a perturbation of the large black hole's ``background'' (Schwarzschild or Kerr) spacetime and use the methods of black-hole perturbation theory, expanding in the small parameter m/M. The particle's motion can be described either as the result of a radiation-reaction ``self-force'' acting in the background spacetime or as geodesic motion in a perturbed spacetime. Several different lines of reasoning lead to the (same) basic O(m/M) ``MiSaTaQuWa'' equations of motion for the particle. In particular, the MiSaTaQuWa equations can be derived by modelling the particle as either a point particle or a small Schwarzschild black hole. The latter is conceptually elegant, but the former is technically much simpler and (surprisingly for a nonlinear field theory such as general relativity) still yields correct results. Modelling the small body as a point particle, its own field is singular along the particle worldline, so it's difficult to formulate a meaningful ``perturbation'' theory or equations of motion there. Detweiler and Whiting found

  16. Rlationship between the aerosol scattering ratio and temperature of atmosphere and the sensitivity of a Doppler wind lidar with iodine filter

    Institute of Scientific and Technical Information of China (English)

    Jinshan Zhu; Yubao Chen; Zhaoai Yan; Songhua Wu; Zhishen Liu

    2008-01-01

    The sensitivity of Doppler wind lidar is an important parameter which affects the performance of Doppler wind lidar. Aerosol scattering ratio, atmospheric temperature, and wind speed obviously affect the mea- surement of Doppler wind lidar with iodine filter. We discuss about the relationship between the measurement sensitivity and the above atmospheric parameters. The numerical relationship between them is given through the theoretical simulation and calculation.

  17. Trans-boundary secondary organic aerosol in western Japan indicated by stable carbon isotope ratio of low volatile water-soluble organic carbon and signal at m/z 44 in organic aerosol mass spectra

    CERN Document Server

    Irei, Satoshi; Hayashi, Masahiko; Hara, Keiichiro; Kaneyasu, Naoki; Sato, Kei; Arakaki, Takemitsu; Hatakeyama, Shiro; Hikida, Toshihide; Shimono, Akio

    2013-01-01

    Field studies were conducted in the winter of 2010 at two rural sites and an urban site in western Japan, and filter samples of total suspended particulate matter were collected every 24-h and analyzed for concentration and stable carbon isotope ratio (delta13C) of low volatile water-soluble organic carbon (LV-WSOC). Concentration of major chemical species in fine aerosol (<1.0 micron) was also measured in real time by Aerodyne aerosol mass spectrometers. Oxidation state of organic aerosol was evaluated using the proportion of signal at m/z 44 (fragment ions of carboxyl group) to the sum of all m/z signals of organic mass spectra (f44). Analyses show a high correlation between LV-WSOC and m/z 44 concentrations, suggesting that the LV-WSOC is substantially composed of water soluble carboxylic acids in the fine aerosol. Plots of delta13C of LV-WSOC versus f44 exhibit systematic trends at the rural sites and random variation at the urban site. The systematic trends qualitatively agree with a simple binary mix...

  18. Diurnal variations of carbonaceous components, major ions, and stable carbon and nitrogen isotope ratios in suburban aerosols from northern vicinity of Beijing

    Science.gov (United States)

    He, Nannan; Kawamura, Kimitaka; Kanaya, Yugo; Wang, Zifa

    2015-12-01

    We report diurnal variations of organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC) and major ions as well as stable carbon and nitrogen isotope ratios (δ13C and δ15N) in ambient aerosols at a suburban site (Mangshan), 40 km north of Beijing, China. We found that aerosol chemical compositions were largely controlled by the air mass transport from Beijing in daytime with southerly winds and by relatively fresh air mass in nighttime from the northern forest areas with northerly winds. Higher concentrations of aerosol mass and total carbon were obtained in daytime. Further, higher OC/EC ratios were recorded in daytime (4.0 ± 1.7) than nighttime (3.2 ± 0.7), suggesting that OC is formed by photochemical oxidation of gaseous precursors in daytime. Contributions of WSOC to OC were slightly higher in daytime (38%) than nighttime (34%), possibly due to secondary formation of WSOC in daytime. We also found higher concentrations of Ca2+ in daytime, which was originated from the construction dust in Beijing area and transported to the sampling site. δ13C ranged from -25.3 to -21.2‰ (ave. -23.5 ± 0.9‰) in daytime and -29.0 to -21.4‰ (-24.0 ± 1.5‰) in nighttime, suggesting that Mangshan aerosols were more influenced by fossil fuel combustion products in daytime and by terrestrial C3 plants in nighttime. This study suggests that daytime air mass delivery from megacity Beijing largely influence the air quality at the receptor site in the north together with photochemical processing of organic aerosols during the atmospheric transport, whereas the Mangshan site is covered with relatively clean air masses at night.

  19. Validating MODIS above-cloud aerosol optical depth retrieved from "color ratio" algorithm using direct measurements made by NASA's airborne AATS and 4STAR sensors

    Science.gov (United States)

    Jethva, Hiren; Torres, Omar; Remer, Lorraine; Redemann, Jens; Livingston, John; Dunagan, Stephen; Shinozuka, Yohei; Kacenelenbogen, Meloe; Segal Rosenheimer, Michal; Spurr, Rob

    2016-10-01

    We present the validation analysis of above-cloud aerosol optical depth (ACAOD) retrieved from the "color ratio" method applied to MODIS cloudy-sky reflectance measurements using the limited direct measurements made by NASA's airborne Ames Airborne Tracking Sunphotometer (AATS) and Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) sensors. A thorough search of the airborne database collection revealed a total of five significant events in which an airborne sun photometer, coincident with the MODIS overpass, observed partially absorbing aerosols emitted from agricultural biomass burning, dust, and wildfires over a low-level cloud deck during SAFARI-2000, ACE-ASIA 2001, and SEAC4RS 2013 campaigns, respectively. The co-located satellite-airborne matchups revealed a good agreement (root-mean-square difference < 0.1), with most matchups falling within the estimated uncertainties associated the MODIS retrievals (about -10 to +50 %). The co-retrieved cloud optical depth was comparable to that of the MODIS operational cloud product for ACE-ASIA and SEAC4RS, however, higher by 30-50 % for the SAFARI-2000 case study. The reason for this discrepancy could be attributed to the distinct aerosol optical properties encountered during respective campaigns. A brief discussion on the sources of uncertainty in the satellite-based ACAOD retrieval and co-location procedure is presented. Field experiments dedicated to making direct measurements of aerosols above cloud are needed for the extensive validation of satellite-based retrievals.

  20. Effect of HC/NOx ratio on the real refractive indices of secondary organic aerosol generated from photooxidation of limonene and α-pinene

    Science.gov (United States)

    Kim, H.; Barkey, B.; Paulson, S. E.

    2011-12-01

    The refractive index is the fundamental property controlling aerosol optical properties. The real refractive indices (mr) of secondary organic aerosols (SOA) generated from the photooxidation of limonene and α-pinene using different HC/NOx ratios are presented. Limonene and α-pinene are estimated to account for about 16 % and 25 % of global monoterpene emissions. Although the limonene emission rate is lower than of α-pinene, it has much higher SOA yields presumabely because it is doubly unsaturated. Refractive indices were retrieved from polar nephelometer measurements using parallel and perpendicular polarized 532 nm light. Retrievals were performed with a genetic algorithm method using Mie-Lorenz scattering theory and measured particle size distributions. The absolute error associated with the mr retrieval is ± 0.03, and the instrument has sufficient sensitivity to achieve reliable retrievals for aerosol mass concentrations of about 20 μg/m3 with particles larger than about 100 nm in diameter. Examination of the limonene SOA data suggests the most important factor controlling the refractive indexes the particle size, which in turn is influenced by the HC/NOx ratio; the refractive index is much less sensitive to the aerosol mass concentration or aerosol aging. The refractive index ranges from1.38 to 1.56 for limonene and from 1.37 to 1.51 for α-pinene, and generally decreases as the HC/NOx ratio increases (6.3 - 33 and 8.1 - 33 for limonene and α-pinene). Our data show that particle diameter is related to the aerosol refractive index; for limonene, as the HC/NOx ratio decreases, the size of particles increases (150 - 310 nm) and mrs increase from about 1.38 to a maximum of about 1.56. α-Pinene has the same trend for mrs; as the HC/NOx ratio decreases, the maximum size of particles increases (100 - 270 nm) and mrs increases from about 1.37 to a maximum of about 1.52. These results give suggest that chemical components controlling the size of SOA are a

  1. Cost Effectiveness Ratio: Evaluation Tool for Comparing the Effectiveness of Similar Extension Programs

    Science.gov (United States)

    Jayaratne, K. S. U.

    2015-01-01

    Extension educators have been challenged to be cost effective in their educational programming. The cost effectiveness ratio is a versatile evaluation indicator for Extension educators to compare the cost of achieving a unit of outcomes or educating a client in similar educational programs. This article describes the cost effectiveness ratio and…

  2. Seasonal and spatial variability of the organic matter-to-organic carbon mass ratios in Chinese urban organic aerosols and a first report of high correlations between aerosol oxalic acid and zinc

    Directory of Open Access Journals (Sweden)

    L. Xing

    2013-01-01

    Full Text Available We calculated the organic matter to organic carbon mass ratios (OM/OC mass ratios in PM2.5 collected from 14 Chinese cities during summer and winter of 2003 and analyzed the causes for their seasonal and spatial variability. The OM/OC mass ratios were calculated two ways. Using a mass balance method, the calculated OM/OC mass ratios averaged 1.92 ± 0.39 yr-round, with no significant seasonal or spatial variation. The second calculation was based on chemical species analyses of the organic compounds extracted from the PM2.5 samples using dichloromethane/methanol and water. The calculated OM/OC mass ratio in summer was relatively high (1.75 ± 0.13 and spatially-invariant, due to vigorous photochemistry and secondary OA production throughout the country. The calculated OM/OC mass ratio in winter (1.59 ± 0.18 was significantly lower than that in summer, with lower values in northern cities (1.51 ± 0.07 than in southern cities (1.65 ± 0.15. This likely reflects the wider usage of coal for heating purposes in northern China in winter, in contrast to the larger contributions from biofuel and biomass burning in southern China in winter. On average, organic matters constituted 36% and 34% of Chinese urban PM2.5 mass in summer and winter, respectively. We reported, for the first time, high correlations between Zn and oxalic acid in Chinese urban aerosols in summer. This is consistent with the formation of stable Zn oxalate complex in the aerosol phase previously proposed by Furukawa and Takahashi (2011. We found that many other dicarboxylic acids were also highly correlated with Zn in the summer Chinese urban aerosol samples, suggesting that they may also form stable organic complexes with Zn. Such formation may have profound implications for the atmospheric abundance and hygroscopic property of aerosol dicarboxylic acids.

  3. Inversion of tropospheric profiles of aerosol extinction and HCHO and NO2 mixing ratios from MAX-DOAS observations in Milano during the summer of 2003 and comparison with independent data sets

    Directory of Open Access Journals (Sweden)

    X. Li

    2011-06-01

    Full Text Available We present aerosol and trace gas profiles derived from MAX-DOAS observations. Our inversion scheme is based on simple profile parameterisations used as input for an atmospheric radiative transfer model (forward model. From a least squares fit of the forward model to the MAX-DOAS measurements, two profile parameters are retrieved including integrated quantities (aerosol optical depth or trace gas vertical column density, and parameters describing the height and shape of the respective profiles. From these results, the aerosol extinction and trace gas mixing ratios can also be calculated. We apply the profile inversion to MAX-DOAS observations during a measurement campaign in Milano, Italy, September 2003, which allowed simultaneous observations from three telescopes (directed to north, west, south. Profile inversions for aerosols and trace gases were possible on 23 days. Especially in the middle of the campaign (17–20 September 2003, enhanced values of aerosol optical depth and NO2 and HCHO mixing ratios were found. The retrieved layer heights were typically similar for HCHO and aerosols. For NO2, lower layer heights were found, which increased during the day. The MAX-DOAS inversion results are compared to independent measurements: (1 aerosol optical depth measured at an AERONET station at Ispra; (2 near-surface NO2 and HCHO (formaldehyde mixing ratios measured by long path DOAS and Hantzsch instruments at Bresso; (3 vertical profiles of HCHO and aerosols measured by an ultra light aircraft. Depending on the viewing direction, the aerosol optical depths from MAX-DOAS are either smaller or larger than those from AERONET observations. Similar comparison results are found for the MAX-DOAS NO2 mixing ratios versus long path DOAS measurements. In contrast, the MAX-DOAS HCHO mixing ratios are generally higher than those from long path DOAS or Hantzsch instruments. The comparison of the HCHO and aerosol profiles from the aircraft showed reasonable

  4. Inversion of tropospheric profiles of aerosol extinction and HCHO and NO2 mixing ratios from MAX-DOAS observations in Milano during the summer of 2003 and comparison with independent data sets

    Directory of Open Access Journals (Sweden)

    U. Platt

    2011-12-01

    Full Text Available We present aerosol and trace gas profiles derived from MAX-DOAS observations. Our inversion scheme is based on simple profile parameterisations used as input for an atmospheric radiative transfer model (forward model. From a least squares fit of the forward model to the MAX-DOAS measurements, two profile parameters are retrieved including integrated quantities (aerosol optical depth or trace gas vertical column density, and parameters describing the height and shape of the respective profiles. From these results, the aerosol extinction and trace gas mixing ratios can also be calculated. We apply the profile inversion to MAX-DOAS observations during a measurement campaign in Milano, Italy, September 2003, which allowed simultaneous observations from three telescopes (directed to north, west, south. Profile inversions for aerosols and trace gases were possible on 23 days. Especially in the middle of the campaign (17–20 September 2003, enhanced values of aerosol optical depth and NO2 and HCHO mixing ratios were found. The retrieved layer heights were typically similar for HCHO and aerosols. For NO2, lower layer heights were found, which increased during the day. The MAX-DOAS inversion results are compared to independent measurements: (1 aerosol optical depth measured at an AERONET station at Ispra; (2 near-surface NO2 and HCHO (formaldehyde mixing ratios measured by long path DOAS and Hantzsch instruments at Bresso; (3 vertical profiles of HCHO and aerosols measured by an ultra light aircraft. Depending on the viewing direction, the aerosol optical depths from MAX-DOAS are either smaller or larger than those from AERONET observations. Similar comparison results are found for the MAX-DOAS NO2 mixing ratios versus long path DOAS measurements. In contrast, the MAX-DOAS HCHO mixing ratios are generally higher than those from long path DOAS or Hantzsch instruments. The comparison of the HCHO and aerosol profiles from the aircraft showed reasonable

  5. Solutions Network Formulation Report. Aerosol Polarimetry Sensor Measurements of Diffuse-to-Global Irradiance Ratio for Improved Forecasting of Plant Productivity and Health

    Science.gov (United States)

    Knowlton, Kelly; Andrews, Jane C.; Ryan, Robert E.

    2007-01-01

    Studies have shown that vegetation is directly sensitive to changes in the diffuse-to-global irradiance ratio and that increased percentage of diffuse irradiation can accelerate photosynthesis. Therefore, measurements of diffuse versus global irradiance could be useful for monitoring crop productivity and overall vegetative health as they relate to the total amount of particulates in the air that result from natural disasters or anthropogenic (manmade) causes. While the components of solar irradiance are measured by satellite and surface sensors and calculated with atmospheric models, disagreement exists between the results, creating a need for more accurate and comprehensive retrievals of atmospheric aerosol parameters. Two satellite sensors--APS and VIIRS--show promise for retrieving aerosol properties at an unprecedented level of accuracy. APS is expected to be launched in December 2008. The planned launch date for VIIRS onboard NPP is September 2009. Identified partners include the USDA s ARS, North Carolina State University, Purdue Climate Change Research Center, and the Cooperative Institute for Research in the Atmosphere at Colorado State University. Although at present no formal DSSs (decision support systems) require accurate values of diffuse-to-global irradiance, this parameter is sufficiently important that models are being developed that will incorporate these measurements. This candidate solution is aligned with the Agricultural Efficiency and Air Quality National Applications.

  6. Local and non-local sources of airborne particulate pollution at Beijing--The ratio of Mg/Al as an element tracer for estimating the contributions of mineral aerosols from outside Beijing

    Institute of Scientific and Technical Information of China (English)

    HAN; Lihui; ZHUANG; Guoshun; SUN; Yele; WANG; Zifa

    2005-01-01

    A new element tracer technique has firstly been established to estimate the contributions of mineral aerosols from both inside and outside Beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to distinguish between the sources of inside and outside Beijing. Mineral aerosol, inorganic pollution aerosol mainly as sulfate and nitrate, and organic aerosol are the major components of airborne particulates in Beijing, of which mineral aerosol accounted for 32%―67% of total suspended particles (TSP), 10%―70% of fine particles (PM2.5), and as high as 74% and 90% of TSP and PM2.5, respectively, in dust storm. The sources from outside Beijing contributed 62% (38%―86%) of the total mineral aerosols in TSP, 69% (52%―90%) in PM10, and 76% (59%―93%) in PM2.5 in spring, and 69% (52%―83%), 79% (52%―93%), and 45% (7%―79%) in TSP, PM10, and PM2.5, respectively, in winter, while only ~20% in summer and autumn. The sources from outside Beijing contributed as high as 97% during dust storm and were the dominant source of airborne particulates in Beijing. The contributions from outside Beijing in spring and winter are higher than those in summer, indicating clearly that it was related to the various meteorological factors.

  7. CALIPSO-inferred aerosol direct radiative effects: Bias estimates using ground-based Raman lidars

    Science.gov (United States)

    Thorsen, Tyler J.; Fu, Qiang

    2015-12-01

    Observational constraints on the change in the radiative energy budget caused by the presence of aerosols, i.e., the aerosol direct radiative effect (DRE), have recently been made using observations from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite (CALIPSO). CALIPSO observations have the potential to provide improved global estimates of aerosol DRE compared to passive sensor-derived estimates due to CALIPSO's ability to perform vertically resolved aerosol retrievals over all surface types and over cloud. In this study, uncertainties in CALIPSO-inferred aerosol DRE are estimated using multiple years of observations from the Atmospheric Radiation Measurement (ARM) program's Raman lidars at midlatitude and tropical sites. We find that CALIPSO is unable to detect all radiatively significant aerosol, resulting in an underestimate in the magnitude of the aerosol DRE by 30-50% at the two ARM sites. The undetected aerosol is likely the consequence of random noise in CALIPSO measurements and therefore will affect global observations as well. This suggests that the global aerosol DRE inferred from CALIPSO observations are likely too weak. Also examined is the impact of the ratio of extinction-to-backscatter (i.e., the lidar ratio) whose value CALIPSO retrievals must assume to obtain the aerosol extinction profile. It is shown that if CALIPSO can reproduce the climatological value of the lidar ratio at a given location, then the aerosol DRE there can be accurately calculated (within about 3%).

  8. Mathematical modeling on multi-stage series crushing ratio distribution based on fuzzy physical programming

    Institute of Scientific and Technical Information of China (English)

    Yu-Long QI; Chen-Chen CAI; Ping-Zhen LANG

    2013-01-01

    Double-layer,multi-roller plate crusher is a new device,that uses a multi-stage series crushing style to break particles,with the crushing ratio distribution directly influencing the machine's performance.Three crushing ratios of 2.25,2.15 and 2.0 1,used for fuzzy physical programming,were determined.The comparison of the optimized result between the double-layer multi-roller plate crusher and a high pressure roll grinder showed that the double-layer multi-roller plate crusher had a better performance,reducing crushing force and wear.

  9. Maximum likelihood estimates with order restrictions on probabilities and odds ratios: A geometric programming approach

    Directory of Open Access Journals (Sweden)

    D. L. Bricker

    1997-01-01

    Full Text Available The problem of assigning cell probabilities to maximize a multinomial likelihood with order restrictions on the probabilies and/or restrictions on the local odds ratios is modeled as a posynomial geometric program (GP, a class of nonlinear optimization problems with a well-developed duality theory and collection of algorithms. (Local odds ratios provide a measure of association between categorical random variables. A constrained multinomial MLE example from the literature is solved, and the quality of the solution is compared with that obtained by the iterative method of El Barmi and Dykstra, which is based upon Fenchel duality. Exploiting the proximity of the GP model of MLE problems to linear programming (LP problems, we also describe as an alternative, in the absence of special-purpose GP software, an easily implemented successive LP approximation method for solving this class of MLE problems using one of the readily available LP solvers.

  10. A Visual Basic program for analyzing oedometer test results and evaluating intergranular void ratio

    Science.gov (United States)

    Monkul, M. Murat; Önal, Okan

    2006-06-01

    A visual basic program (POCI) is proposed and explained in order to analyze oedometer test results. Oedometer test results have vital importance from geotechnical point of view, since settlement requirements usually control the design of foundations. The software POCI is developed in order perform the necessary calculations for convential oedometer test. The change of global void ratio and stress-strain characteristics can be observed both numerically and graphically. It enables the users to calculate some parameters such as coefficient of consolidation, compression index, recompression index, and preconsolidation pressure depending on the type and stress history of the soil. Moreover, it adopts the concept of intergranular void ratio which may be important especially in the compression behavior of sandy soils. POCI shows the variation of intergranular void ratio and also enables the users to calculate granular compression index.

  11. Aerosol Property Comparison Within and Above the ABL at the ARM Program SGP Site

    Energy Technology Data Exchange (ETDEWEB)

    Delle Monache, L

    2002-05-01

    This thesis determines what, if any, measurements of aerosol properties made at the Earth surface are representative of those within the entire air column. Data from the Atmospheric Radiation Measurement site at the Southern Great Plains, the only location in the world where ground-based and in situ airborne measurements are routinely made. Flight legs during the one-year period from March 2000 were categorized as either within or above the atmospheric boundary layer (ABL) by use of an objective mixing height determination technique. Correlations between aerosol properties measured at the surface and those within and above the ABL were computed. Aerosol extensive and intensive properties measured at the surface were found representative of values within the ABL, but not of within the free atmosphere.

  12. Spent fuel sabotage test program, characterization of aerosol dispersal : technical review and analysis supplement.

    Energy Technology Data Exchange (ETDEWEB)

    Durbin, Samuel G.; Lindgren, Eric Richard

    2009-07-01

    This project seeks to provide vital data required to assess the consequences of a terrorist attack on a spent fuel transportation cask. One such attack scenario involves the use of conical shaped charges (CSC), which are capable of damaging a spent fuel transportation cask. In the event of such an attack, the amount of radioactivity that may be released as respirable aerosols is not known with great certainty. Research to date has focused on measuring the aerosol release from single short surrogate fuel rodlets subjected to attack by a small CSC device in various aerosol chamber designs. The last series of three experiments tested surrogate fuel rodlets made with depleted uranium oxide ceramic pellets in a specially designed double chamber aerosol containment apparatus. This robust testing apparatus was designed to prevent any radioactive release and allow high level radioactive waste disposal of the entire apparatus following testing of actual spent fuel rodlets as proposed. DOE and Sandia reviews of the project to date identified a number of issues. The purpose of this supplemental report is to address and document the DOE review comments and to resolve the issues identified in the Sandia technical review.

  13. Sulfur and nitrogen compounds in urban aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R L

    1979-01-01

    This paper reports results from a detailed chemical and meteorological data base that has been accumulated for the New York City subregion. Aerosol sampling during August 1976 and February 1977 sampling periods was done only in an urban New York site and a background site at High Point, NJ. The sampling program was expanded to Brookhaven (Long Island) and New Haven, Connecticut sites during summer 1977 and winter 1978 sampling. Time resolution for aerosol filter samples was 6 hr, with some 3 hr sampling for the latter three periods. Parameters measured included chemical constituents: strong acid (quartz filters only), ammonium, sulfate and nitrate, sulfuric acid (limited data); physical parameters: aerosol size distributions by cascade impactor, cyclone sampler, EAA, on optical counter and a special diffusion battery-CNC apparatus; light scattering nephelometer and other instrumentation; chemically-speciated size classification by diffusion sampler; trace metals by atomic absorption; halogen compounds by NAA; meteorological measurements of RH, temperature, wind speed and direction; gaseous measurements of SO/sub 2/, ozone, NO/sub x/ and hydrocarbons at some locations for some sampling periods. The existence of aerosol sulfate in the ambient environment predominantly in the chemical form of sulfuric acid mostly neutralized by ammonia is now well documented. The average composition of fine particle (< 3.5 ..mu..m) sulfate in summer 1976 aerosols was approximately that letovicite ((NH/sub 4/)/sub 3/H(SO/sub 4/)/sub 2/). Based on the impactor data, about 85% of the aerosol sulfate mass was in the fine particle fraction. About 50% of this aerosol sulfate was deduced to be in the suboptical size regime (< 0.25 ..mu..m) from diffusion processor data. The H/sup +//SO/sub 4//sup 2 -/ ratio in suboptical aerosols did not significantly differ from that in fine fraction aerosol. The coarse particle sulfate was not associated with H/sup +/ or NH/sub 4//sup +/ and comprised

  14. Nevada's Class-Size Reduction Program. Nevada Revised Statutes 388.700-388.730: "Program To Reduce the Pupil-Teacher Ratio." Background Paper 97-7.

    Science.gov (United States)

    Sturm, H. Pepper

    In 1989, the Nevada Legislature enacted the Class-Size Reduction (CSR) Act. The measure was designed to reduce the pupil-teacher ratio in the public schools, particularly in the earliest grades. The program was scheduled to proceed in several phases. The first step reduced the student-teacher ratio in selected kindergartens and first grade classes…

  15. Development of a dual-internal-reference technique to improve accuracy when determining bacterial 16S rRNA:16S rRNA gene ratio with application to Escherichia coli liquid and aerosol samples.

    Science.gov (United States)

    Zhen, Huajun; Krumins, Valdis; Fennell, Donna E; Mainelis, Gediminas

    2015-10-01

    Accurate enumeration of rRNA content in microbial cells, e.g. by using the 16S rRNA:16S rRNA gene ratio, is critical to properly understand its relationship to microbial activities. However, few studies have considered possible methodological artifacts that may contribute to the variability of rRNA analysis results. In this study, a technique utilizing genomic DNA and 16S rRNA from an exogenous species (Pseudomonas fluorescens) as dual internal references was developed to improve accuracy when determining the 16S rRNA:16S rRNA gene ratio of a target organism, Escherichia coli. This technique was able to adequately control the variability in sample processing and analysis procedures due to nucleic acid (DNA and RNA) losses, inefficient reverse transcription of RNA, and inefficient PCR amplification. The measured 16S rRNA:16S rRNA gene ratio of E. coli increased by 2-3 fold when E. coli 16S rRNA gene and 16S rRNA quantities were normalized to the sample-specific fractional recoveries of reference (P. fluorescens) 16S rRNA gene and 16S rRNA, respectively. In addition, the intra-sample variation of this ratio, represented by coefficients of variation from replicate samples, decreased significantly after normalization. This technique was applied to investigate the temporal variation of 16S rRNA:16S rRNA gene ratio of E. coli during its non-steady-state growth in a complex liquid medium, and to E. coli aerosols when exposed to particle-free air after their collection on a filter. The 16S rRNA:16S rRNA gene ratio of E. coli increased significantly during its early exponential phase of growth; when E. coli aerosols were exposed to extended filtration stress after sample collection, the ratio also increased. In contrast, no significant temporal trend in E. coli 16S rRNA:16S rRNA gene ratio was observed when the determined ratios were not normalized based on the recoveries of dual references. The developed technique could be widely applied in studies of relationship between

  16. Comparison of aerosol optical depth of UV-B Monitoring and Research Program (UVMRP), AERONET and MODIS over continental United States

    Institute of Scientific and Technical Information of China (English)

    Hongzhao TANG; Maosi CHEN; John DAVIS; Wei GAO

    2013-01-01

    The concern about the role of aerosols as to their effect in the Earth-Atmosphere system requires observation at multiple temporal and spatial scales.The Moderate Resolution Imaging Spectroradiameters (MODIS) is the main aerosol optical depth (AOD)monitoring satellite instrument,and its accuracy and uncertainty need to be validated against ground based measurements routinely.The comparison between two ground AOD measurement programs,the United States Department of Agriculture (USDA) Ultraviolet-B Monitoring and Research Program (UVMRP) and the Aerosol Robotic Network (AERONET) program,confirms the consistency between them.The intercomparison between the MODIS AOD,the AERONET AOD,and the UVMRP AOD suggests that the UVMRP AOD measurements are suited to be an alternative ground-based validation source for satellite AOD products.The experiments show that the spatial-temporal dependency between the MODIS AOD and the UVMRP AOD is positive in the sense that the MODIS AOD compare more favorably with the UVMRP AOD as the spatial and temporal intervals are increased.However,the analysis shows that the optimal spatial interval for all time windows is defined by an angular subtense of around 1° to 1.25°,while the optimal time window is around 423 to 483 minutes at most spatial intervals.The spatial-temporal approach around 1.25° & 423 minutes shows better agreement than the prevalent strategy of 0.25° & 60 minutes found in other similar investigations.Research Program (UVMRP),Aerosol Robotic Network (AERONET),Moderate Resolution Imaging Spectroradiameters (MODIS),validation,spatial-temporal approach

  17. Comparison of aerosol optical depth of UV-B monitoring and research program (UVMRP), AERONET and MODIS over continental united states

    Science.gov (United States)

    Tang, Hongzhao; Chen, Maosi; Davis, John; Gao, Wei

    2013-06-01

    The concern about the role of aerosols as to their effect in the Earth-Atmosphere system requires observation at multiple temporal and spatial scales. The Moderate Resolution Imaging Spectroradiameters (MODIS) is the main aerosol optical depth (AOD) monitoring satellite instrument, and its accuracy and uncertainty need to be validated against ground based measurements routinely. The comparison between two ground AOD measurement programs, the United States Department of Agriculture (USDA) Ultraviolet-B Monitoring and Research Program (UVMRP) and the Aerosol Robotic Network (AERONET) program, confirms the consistency between them. The intercomparison between the MODIS AOD, the AERONET AOD, and the UVMRP AOD suggests that the UVMRP AOD measurements are suited to be an alternative ground-based validation source for satellite AOD products. The experiments show that the spatial-temporal dependency between the MODIS AOD and the UVMRP AOD is positive in the sense that the MODIS AOD compare more favorably with the UVMRP AOD as the spatial and temporal intervals are increased. However, the analysis shows that the optimal spatial interval for all time windows is defined by an angular subtense of around 1° to 1.25°, while the optimal time window is around 423 to 483 minutes at most spatial intervals. The spatial-temporal approach around 1.25° & 423 minutes shows better agreement than the prevalent strategy of 0.25° & 60 minutes found in other similar investigations.

  18. Programs to Compute Distribution Functions and Critical Values for Extreme Value Ratios for Outlier Detection

    Directory of Open Access Journals (Sweden)

    George C. McBane

    2006-05-01

    Full Text Available A set of FORTRAN subprograms is presented to compute density and cumulative distribution functions and critical values for the range ratio statistics of Dixon (1951, The Annals of Mathematical Statistics These statistics are useful for detection of outliers in small samples.

  19. Comparison of Aerosol Properties Within and Above the ABL at the ARM Program's SGP Site

    Energy Technology Data Exchange (ETDEWEB)

    Delle Monache, L

    2002-05-01

    The goal of this thesis is to determine under what conditions, if any, measurements of aerosol properties made at the Earth's surface are representative of aerosol properties within the column of air above the surface. This thesis will use data from the Atmospheric Radiation Measurement (ARM) site at the Southern Great Plains (SGP) which is the only location in the world where ground-based and in situ airborne measurements are made on a routine basis. All flight legs in the one-year period from March 2000-March 2001 were categorized as either within or above the atmospheric boundary layer using an objective mixing height determination technique. The correlations between the aerosol properties measured at the surface and the measured within and above the ABL were then computed. The conclusion of this comparison is that the aerosol extensive and intensive properties measured at the surface are representative of values within the ABL, but not within the free atmosphere.

  20. Intercomparison of aerosol optical parameters from WALI and R-MAN510 aerosol Raman lidars in the framework of HyMeX campaign

    Science.gov (United States)

    Boytard, Mai-Lan; Royer, Philippe; Chazette, Patrick; Shang, Xiaoxia; Marnas, Fabien; Totems, Julien; Bizard, Anthony; Bennai, Baya; Sauvage, Laurent

    2013-04-01

    The HyMeX program (Hydrological cycle in Mediterranean eXperiment) aims at improving our understanding of hydrological cycle in the Mediterranen and at a better quantification and forecast of high-impact weather events in numerical weather prediction models. The first Special Observation Period (SOP1) took place in September/October 2012. During this period two aerosol Raman lidars have been deployed at Menorca Island (Spain) : one Water-vapor and Aerosol Raman LIdar (WALI) operated by LSCE/CEA (Laboratoire des Sciences du Climat et de l'Environnement/Commissariat à l'Energie Atomique) and one aerosol Raman and dual-polarization lidar (R-Man510) developed and commercialized by LEOSPHERE company. Both lidars have been continuously running during the campaign and have provided information on aerosol and cloud optical properties under various atmospheric conditions (maritime background aerosols, dust events, cirrus clouds...). We will present here the results of intercomparisons between R-Man510, and WALI aerosol lidar systems and collocated sunphotometer measurements. Limitations and uncertainties on the retrieval of extinction coefficients, depolarization ratio, aerosol optical depths and detection of atmospheric structures (planetary boundary layer height, aerosol/cloud layers) will be discussed according atmospheric conditions. The results will also be compared with theoretical uncertainty assessed with direct/inverse model of lidar profiles.

  1. The effects of injury preventive warm-up programs on knee strength ratio in young male professional soccer players.

    Directory of Open Access Journals (Sweden)

    Abdolhamid Daneshjoo

    Full Text Available PURPOSE: We aimed to investigate the effect of FIFA 11+ (11+ and HarmoKnee injury preventive warm-up programs on conventional strength ratio (CSR, dynamic control ratio (DCR and fast/slow speed ratio (FSR in young male professional soccer players. These ratios are related to the risk of injury to the knee in soccer players. METHODS: Thirty-six players were divided into 3 groups; FIFA 11+, HarmoKnee and control (n = 12 per group. These exercises were performed 3 times per week for 2 months (24 sessions. The CSR, DCR and FSR were measured before and after the intervention. RESULTS: After training, the CSR and DCR of knee muscles in both groups were found to be lower than the published normal values (0.61, 0.72, and 0.78 during 60°.s(-1, 180°.s(-1 and 300°.s(-1, respectively. The CSR (60°.s(-1 increased by 8% and FSR in the quadriceps of the non-dominant leg by 8% in the 11+. Meanwhile, the DCR in the dominant and non-dominant legs were reduced by 40% and 30% respectively in the 11+. The CSR (60°.s(-1 in the non-dominant leg showed significant differences between the 11+, HarmoKnee and control groups (p = 0.02. As for the DCR analysis between groups, there were significant differences in the non-dominant leg between both programs with the control group (p = 0.04. For FSR no significant changes were found between groups. CONCLUSIONS: It can be concluded that the 11+ improved CSR and FSR, but the HarmoKnee program did not demonstrate improvement. We suggest adding more training elements to the HarmoKnee program that aimed to enhance hamstring strength (CSR, DCR and FSR. Professional soccer players have higher predisposition of getting knee injuries because hamstring to quadriceps ratio were found to be lower than the average values. It seems that the 11+ have potentials to improve CSR and FSR as well as prevent knee injuries in soccer players.

  2. Gene expression programming approach for the estimation of moisture ratio in herbal plants drying with vacuum heat pump dryer

    Science.gov (United States)

    Dikmen, Erkan; Ayaz, Mahir; Gül, Doğan; Şahin, Arzu Şencan

    2017-02-01

    The determination of drying behavior of herbal plants is a complex process. In this study, gene expression programming (GEP) model was used to determine drying behavior of herbal plants as fresh sweet basil, parsley and dill leaves. Time and drying temperatures are input parameters for the estimation of moisture ratio of herbal plants. The results of the GEP model are compared with experimental drying data. The statistical values as mean absolute percentage error, root-mean-squared error and R-square are used to calculate the difference between values predicted by the GEP model and the values actually observed from the experimental study. It was found that the results of the GEP model and experimental study are in moderately well agreement. The results have shown that the GEP model can be considered as an efficient modelling technique for the prediction of moisture ratio of herbal plants.

  3. Lidar Ratio Derived for Pure Dust Aerosols: Multi-Year Micro Pulse Lidar Observations in a Saharan Dust-Influenced Region

    Science.gov (United States)

    Córdoba-Jabonero, Carmen; Adame, José Antonio; Campbell, James R.; Cuevas, Emilio; Díaz, Juan Pedro; Expósito, Francisco; Gil-Ojeda, Manuel

    2016-06-01

    A seasonal distribution of the Lidar Ratio (LR, extinction-to-backscattering coefficient ratio) for pure Saharan dust particles has been achieved. Simultaneous MPLNET/Micro Pulse lidar measurements in synergy with AERONET sun-photometer data were collected in the Tenerife area, a Saharan dust-influenced region, from June 2007 to November 2009. Dusty cases were mostly observed in summertime (71.4 % of total dusty cases). No differences were found among the LR values derived for spring, summertime and autumn times (a rather consistent seasonally averaged LR value of 57 sr is found). In wintertime, however, a higher mean LR is derived (65 sr), associated likely with a potential contamination from fine biomass burning particles coming from Sahel area during wintertime deforestation fires period. Results, obtained from a free-tropospheric pristine station (AEMET/Izaña Observatory) under Saharan dust intrusion occurrence, provide a more realistic perspective about LR values to be used in elastic lidar-derived AOD inversion for Saharan pure dust particles, and hence in improving CALIPSO AOD retrievals.

  4. Lidar Ratio Derived for Pure Dust Aerosols: Multi-Year Micro Pulse Lidar Observations in a Saharan Dust-Influenced Region

    Directory of Open Access Journals (Sweden)

    Córdoba-Jabonero Carmen

    2016-01-01

    Full Text Available A seasonal distribution of the Lidar Ratio (LR, extinction-to-backscattering coefficient ratio for pure Saharan dust particles has been achieved. Simultaneous MPLNET/Micro Pulse lidar measurements in synergy with AERONET sun-photometer data were collected in the Tenerife area, a Saharan dust-influenced region, from June 2007 to November 2009. Dusty cases were mostly observed in summertime (71.4 % of total dusty cases. No differences were found among the LR values derived for spring, summertime and autumn times (a rather consistent seasonally averaged LR value of 57 sr is found. In wintertime, however, a higher mean LR is derived (65 sr, associated likely with a potential contamination from fine biomass burning particles coming from Sahel area during wintertime deforestation fires period. Results, obtained from a free-tropospheric pristine station (AEMET/Izaña Observatory under Saharan dust intrusion occurrence, provide a more realistic perspective about LR values to be used in elastic lidar-derived AOD inversion for Saharan pure dust particles, and hence in improving CALIPSO AOD retrievals.

  5. CATS Aerosol Typing and Future Directions

    Science.gov (United States)

    McGill, Matt; Yorks, John; Scott, Stan; Palm, Stephen; Hlavka, Dennis; Hart, William; Nowottnick, Ed; Selmer, Patrick; Kupchock, Andrew; Midzak, Natalie; Trepte, Chip; Vaughan, Mark; Colarco, Peter; da Silva, Arlindo

    2016-01-01

    The Cloud Aerosol Transport System (CATS), launched in January of 2015, is a lidar remote sensing instrument that will provide range-resolved profile measurements of atmospheric aerosols and clouds from the International Space Station (ISS). CATS is intended to operate on-orbit for at least six months, and up to three years. Status of CATS Level 2 and Plans for the Future:Version. 1. Aerosol Typing (ongoing): Mode 1: L1B data released later this summer; L2 data released shortly after; Identify algorithm biases (ex. striping, FOV (field of view) biases). Mode 2: Processed Released Currently working on correcting algorithm issues. Version 2 Aerosol Typing (Fall, 2016): Implementation of version 1 modifications Integrate GEOS-5 aerosols for typing guidance for non spherical aerosols. Version 3 Aerosol Typing (2017): Implementation of 1-D Var Assimilation into GEOS-5 Dynamic lidar ratio that will evolve in conjunction with simulated aerosol mixtures.

  6. TCF7L2 polymorphism, weight loss and proinsulin:insulin ratio in the diabetes prevention program.

    Directory of Open Access Journals (Sweden)

    Jeanne M McCaffery

    Full Text Available TCF7L2 variants have been associated with type 2 diabetes, body mass index (BMI, and deficits in proinsulin processing and insulin secretion. Here we sought to test whether these effects were apparent in high-risk individuals and modify treatment responses.We examined the potential role of the TCF7L2 rs7903146 variant in predicting resistance to weight loss or a lack of improvement of proinsulin processing during 2.5-years of follow-up participants (N = 2,994 from the Diabetes Prevention Program (DPP, a randomized controlled trial designed to prevent or delay diabetes in high-risk adults.We observed no difference in the degree of weight loss by rs7903146 genotypes. However, the T allele (conferring higher risk of diabetes at rs7903146 was associated with higher fasting proinsulin at baseline (P<0.001, higher baseline proinsulin:insulin ratio (p<0.0001 and increased proinsulin:insulin ratio over a median of 2.5 years of follow-up (P = 0.003. Effects were comparable across treatment arms.The combination of a lack of impact of the TCF7L2 genotypes on the ability to lose weight, but the presence of a consistent effect on the proinsulin:insulin ratio over the course of DPP, suggests that high-risk genotype carriers at this locus can successfully lose weight to counter diabetes risk despite persistent deficits in insulin production.

  7. Program GICC, final report (March 2005), inventory of carbonaceous aerosol particles from 1860 to 2100 or which carbonaceous aerosol for a significant climatic regional/global impact?; Programme GICC, RAPPORT DEFINITIF (Mars 2005), inventaire d'emissions d'aerosol carbone de 1860 a 2100 ou quelles emissions d'aerosol carbone pour un impact climatique regional/global significatif?

    Energy Technology Data Exchange (ETDEWEB)

    Cachier, H.; Guinot, B. [Laboratoire des Sciences du Climat et de l' Environnment, UMR CEA/CNRS 1572 - CEA Saclay, 91 - Gif sur Yvette (France); Criqui, P.; Mima, S. [IEPE, 38 - Grenoble (France); Brignon, J.M. [INERIS, 60 - Verneuil-en-Halatte (France); Penner, J. [Michigan Univ., Ann Arbor, MI (United States); Carmichael, G. [Iowa Univ., Iowa City, IA (United States); Gadi, R. [National Physical Lab., New Delhi (India); Denier Van der Gon, H. [TNO Hollande (Netherlands); Gregoire, J.M. [JRC, Ispra (Italy); Liousse, C.; Michel, C.; Guillaume, B.; Junker, C

    2007-07-01

    The aim of our program is to determine past, present and future emission inventories of carbonaceous particles from 1860 to 2100 for fossil fuel and biofuel sources. Emission inventories for savannah and forest fires have been developed by using burnt area products given by satellite for Asia and Africa. The strong collaboration with the different groups attending this GICC program has allowed to develop the following results. 1- With the improvement of algorithms and new choices for emission factors, emission inventories for black carbon (BC), primary organic carbon (OCp) and total organic carbon (OCtot) have been constructed for the period 1950 to 1997 for fossil fuel and biofuel sources. With these new development, biofuel sources have been seen to be significant, especially in the developing countries. 2- Past inventories have been developed for fossil fuel and biofuel sources from 1860 to 1997 by taking into account the evolution of fuel consumption, fuel use and emission factors. 3- Savannah and forest fire inventories have been constructed based on burnt area products, for Africa (1981-1991, 2000) and Asia (2000-2001). These results show the importance of using real time data instead of statistics. 4-Future emission inventory of black carbon by fossil fuel sources has been constructed for 2100 following the IPCC scenario A2 (catastrophic case) and B1 (perfect world). 5-Characterization of biofuel emissions has been realized by organizing an experiment in a combustion chamber where indian and chinese biofuels (fuelwood, agricultural wastes, dung-cake etc..). were burnt, reproducing the burning methods used in these countries. 6-Finally, the differences between the existing inventories of carbonaceous aerosols has been explained. (A.L.B.)

  8. Scientific Infrastructure to Support Atmospheric Science and Aerosol Science for the Department of Energy's Atmospheric Radiation Measurement Programs at Barrow, Alaska.

    Science.gov (United States)

    Lucero, D. A.; Ivey, M.; Helsel, F.; Hardesty, J.; Dexheimer, D.

    2015-12-01

    Scientific infrastructure to support atmospheric science and aerosol science for the Department of Energy's Atmospheric Radiation Measurement programs at Barrow, Alaska.The Atmospheric Radiation Measurement (ARM) Program's located at Barrow, Alaska is a U.S. Department of Energy (DOE) site. The site provides a scientific infrastructure and data archives for the international Arctic research community. The infrastructure at Barrow has been in place since 1998, with many improvements since then. Barrow instruments include: scanning precipitation Radar-cloud radar, Doppler Lidar, Eddy correlation flux systems, Ceilometer, Manual and state-of-art automatic Balloon sounding systems, Atmospheric Emitted Radiance Interferometer (AERI), Micro-pulse Lidar (MPL), Millimeter cloud radar, High Spectral Resolution Lidar (HSRL) along with all the standard metrological measurements. Data from these instruments is placed in the ARM data archives and are available to the international research community. This poster will discuss what instruments are at Barrow and the challenges of maintaining these instruments in an Arctic site.

  9. The Atmospheric Radiation Measurement Program May 2003 Intensive Operations Period Examining Aerosol Properties and Radiative Influences: Preface to Special Section

    Science.gov (United States)

    Ferrare, Richard; Feingold, Graham; Ghan, Steven; Ogren, John; Schmid, Beat; Schwartz, Stephen E.; Sheridan, Pat

    2006-01-01

    Atmospheric aerosols influence climate by scattering and absorbing radiation in clear air (direct effects) and by serving as cloud condensation nuclei, modifying the microphysical properties of clouds, influencing radiation and precipitation development (indirect effects). Much of present uncertainty in forcing of climate change is due to uncertainty in the relations between aerosol microphysical and optical properties and their radiative influences (direct effects) and between microphysical properties and their ability to serve as cloud condensation nuclei at given supersaturations (indirect effects). This paper introduces a special section that reports on a field campaign conducted at the Department of Energy Atmospheric Radiation Measurement site in North Central Oklahoma in May, 2003, examining these relations using in situ airborne measurements and surface-, airborne-, and space-based remote sensing.

  10. Stratospheric Aerosol Measurements

    Science.gov (United States)

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

    1998-01-01

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

  11. Time Series of Aerosol Column Optical Depth at the Barrow, Alaska, ARM Climate Research Facility for 2008 Fourth Quarter 2009 ARM and Climate Change Prediction Program Metric Report

    Energy Technology Data Exchange (ETDEWEB)

    C Flynn; AS Koontz; JH Mather

    2009-09-01

    The uncertainties in current estimates of anthropogenic radiative forcing are dominated by the effects of aerosols, both in relation to the direct absorption and scattering of radiation by aerosols and also with respect to aerosol-related changes in cloud formation, longevity, and microphysics (See Figure 1; Intergovernmental Panel on Climate Change, Assessment Report 4, 2008). Moreover, the Arctic region in particular is especially sensitive to changes in climate with the magnitude of temperature changes (both observed and predicted) being several times larger than global averages (Kaufman et al. 2009). Recent studies confirm that aerosol-cloud interactions in the arctic generate climatologically significant radiative effects equivalent in magnitude to that of green house gases (Lubin and Vogelmann 2006, 2007). The aerosol optical depth is the most immediate representation of the aerosol direct effect and is also important for consideration of aerosol-cloud interactions, and thus this quantity is essential for studies of aerosol radiative forcing.

  12. Aerosolized Antibiotics.

    Science.gov (United States)

    Restrepo, Marcos I; Keyt, Holly; Reyes, Luis F

    2015-06-01

    Administration of medications via aerosolization is potentially an ideal strategy to treat airway diseases. This delivery method ensures high concentrations of the medication in the targeted tissues, the airways, with generally lower systemic absorption and systemic adverse effects. Aerosolized antibiotics have been tested as treatment for bacterial infections in patients with cystic fibrosis (CF), non-CF bronchiectasis (NCFB), and ventilator-associated pneumonia (VAP). The most successful application of this to date is treatment of infections in patients with CF. It has been hypothesized that similar success would be seen in NCFB and in difficult-to-treat hospital-acquired infections such as VAP. This review summarizes the available evidence supporting the use of aerosolized antibiotics and addresses the specific considerations that clinicians should recognize when prescribing an aerosolized antibiotic for patients with CF, NCFB, and VAP.

  13. Instrumentation for tropospheric aerosol characterization

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-31

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

  14. Aerosol Layering Characterization Near the Gobi Desert by a Double Polarization Lidar System

    Directory of Open Access Journals (Sweden)

    Zhao Y.

    2016-01-01

    Optical properties of aerosol layers developing in the atmosphere have been analyzed and lidar data are discussed in terms of profiles of aerosol backscatter coefficient at 355nm, 532nm, aerosol extinction coefficient at 355nm, aerosol depolarization ratio at 355nm and 532nm and water vapor mixing ratio. Depolarization ratio measured simultaneously at two wavelengths allowed also to study its dependence on the wavelength.

  15. Optimized sparse-particle aerosol representations for modeling cloud-aerosol interactions

    Science.gov (United States)

    Fierce, Laura; McGraw, Robert

    2016-04-01

    Sparse representations of atmospheric aerosols are needed for efficient regional- and global-scale chemical transport models. Here we introduce a new framework for representing aerosol distributions, based on the method of moments. Given a set of moment constraints, we show how linear programming can be used to identify collections of sparse particles that approximately maximize distributional entropy. The collections of sparse particles derived from this approach reproduce CCN activity of the exact model aerosol distributions with high accuracy. Additionally, the linear programming techniques described in this study can be used to bound key aerosol properties, such as the number concentration of CCN. Unlike the commonly used sparse representations, such as modal and sectional schemes, the maximum-entropy moment-based approach is not constrained to pre-determined size bins or assumed distribution shapes. This study is a first step toward a new aerosol simulation scheme that will track multivariate aerosol distributions with sufficient computational efficiency for large-scale simulations.

  16. Pre-Cloud Aerosol, Cloud Droplet Concentration, and Cloud Condensation Nuclei from the VAMOS Ocean-Cloud-Atmosphere Land Study (VOCALS) Field Campaign First Quarter 2010 ASR Program Metric Report

    Energy Technology Data Exchange (ETDEWEB)

    Kleinman, LI; Springston, SR; Daum, PH; Lee, Y-N; Sedlacek, AJ; Senum, G; Wang, J

    2011-08-31

    In this, the first of a series of Program Metric Reports, we (1) describe archived data from the DOE G-1 aircraft, (2) illustrate several relations between sub-cloud aerosol, CCN, and cloud droplets pertinent to determining the effects of pollutant sources on cloud properties, and (3) post to the data archive an Excel spreadsheet that contains cloud and corresponding sub-cloud data.

  17. TOMS Absorbing Aerosol Index

    Data.gov (United States)

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

  18. Aerosol Observation System

    Data.gov (United States)

    Oak Ridge National Laboratory — The aerosol observation system (AOS) is the primary Atmospheric Radiation Measurement (ARM) platform for in situ aerosol measurements at the surface. The principal...

  19. Separating Dust Mixtures and Other External Aerosol Mixtures Using Airborne High Spectral Resolution Lidar Data

    Science.gov (United States)

    Burton, S. P.; Ferrare, R. A.; Vaughan, M.; Hostetler, C. A.; Rogers, R. R.; Hair, J. W.; Cook, A. L.; Harper, D. B.

    2013-12-01

    Knowledge of aerosol type is important for source attribution and for determining the magnitude and assessing the consequences of aerosol radiative forcing. The NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1) has acquired considerable datasets of both aerosol extensive parameters (e.g. aerosol optical depth) and intensive parameters (e.g. aerosol depolarization ratio, lidar ratio) that can be used to infer aerosol type. An aerosol classification methodology has been used extensively to classify HSRL-1 aerosol measurements of different aerosol types including dust, smoke, urban pollution, and marine aerosol. However, atmospheric aerosol is frequently not a single pure type, but instead occurs as a mixture of types, and this mixing affects the optical and radiative properties of the aerosol. Here we present a comprehensive and unified set of rules for characterizing external mixtures using several key aerosol intensive parameters: extinction-to-backscatter ratio (i.e. lidar ratio), backscatter color ratio, and depolarization ratio. Our mixing rules apply not just to the scalar values of aerosol intensive parameters, but to multi-dimensional normal distributions with variance in each measurement dimension. We illustrate the applicability of the mixing rules using examples of HSRL-1 data where mixing occurred between different aerosol types, including advected Saharan dust mixed with the marine boundary layer in the Caribbean Sea and locally generated dust mixed with urban pollution in the Mexico City surroundings. For each of these cases we infer a time-height cross section of mixing ratio along the flight track and we partition aerosol extinction into portions attributed to the two pure types. Since multiple aerosol intensive parameters are measured and included in these calculations, the techniques can also be used for cases without significant depolarization (unlike similar work by earlier researchers), and so a third example of a

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

    Science.gov (United States)

    Gladstone, G. Randall

    2001-01-01

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

  1. Highly Resolved Paleoclimatic Aerosol Records

    DEFF Research Database (Denmark)

    Kettner, Ernesto

    In ice cores a plethora of proxies for paleoclimatic conditions is archived. Air trapped in the ice during firnification allows for direct measurements of the concentrations and isotope ratios of paleoatmospheric gases while, the isotopic composition of the ice matrix itself is related...... to paleotemperatures. Impurities in the matrix are comprised of particulate and soluble aerosols, each carrying information on its source’s activitiy and|or proximity. Opposed to gases and water isotopes, the seasonality of many aerosols is not smoothed out in the firn column so that large concentration gradients...... with frequently changing signs are preserved. Therefore, these aerosol records can be used for dating by annual layer counting. However, with increasing depth the annual layer thicknesses decreases due to pressure and ice flow and accurate dating is possible only as long as the rapid variations can be resolved...

  2. Updated African biomass burning emission inventories in the framework of the AMMA-IDAF program, with an evaluation of combustion aerosols

    Directory of Open Access Journals (Sweden)

    C. Liousse

    2010-10-01

    Full Text Available African biomass burning emission inventories for gaseous and particulate species have been constructed at a resolution of 1 km by 1km with daily coverage for the 2000–2007 period. These inventories are higher than the GFED2 inventories, which are currently widely in use. Evaluation specifically focusing on combustion aerosol has been carried out with the ORISAM-TM4 global chemistry transport model which includes a detailed aerosol module. This paper compares modeled results with measurements of surface BC concentrations and scattering coefficients from the AMMA Enhanced Observations period, aerosol optical depths and single scattering albedo from AERONET sunphotometers, LIDAR vertical distributions of extinction coefficients as well as satellite data. Aerosol seasonal and interannual evolutions over the 2004–2007 period observed at regional scale and more specifically at the Djougou (Benin and Banizoumbou (Niger AMMA/IDAF sites are well reproduced by our global model, indicating that our biomass burning emission inventory appears reasonable.

  3. Comparison of MADE3-simulated and observed aerosol distributions with a focus on aerosol vertical profiles

    Science.gov (United States)

    Kaiser, Christopher; Hendricks, Johannes; Righi, Mattia; Jöckel, Patrick

    2016-04-01

    The reliability of aerosol radiative forcing estimates from climate models depends on the accuracy of simulated global aerosol distribution and composition, as well as on the models' representation of the aerosol-cloud and aerosol-radiation interactions. To help improve on previous modeling studies, we recently developed the new aerosol microphysics submodel MADE3 that explicitly tracks particle mixing state in the Aitken, accumulation, and coarse mode size ranges. We implemented MADE3 into the global atmospheric chemistry general circulation model EMAC and evaluated it by comparison of simulated aerosol properties to observations. Compared properties include continental near-surface aerosol component concentrations and size distributions, continental and marine aerosol vertical profiles, and nearly global aerosol optical depth. Recent studies have shown the specific importance of aerosol vertical profiles for determination of the aerosol radiative forcing. Therefore, our focus here is on the evaluation of simulated vertical profiles. The observational data is taken from campaigns between 1990 and 2011 over the Pacific Ocean, over North and South America, and over Europe. The datasets include black carbon and total aerosol mass mixing ratios, as well as aerosol particle number concentrations. Compared to other models, EMAC with MADE3 yields good agreement with the observations - despite a general high bias of the simulated mass mixing ratio profiles. However, BC concentrations are generally overestimated by many models in the upper troposphere. With MADE3 in EMAC, we find better agreement of the simulated BC profiles with HIPPO data than the multi-model average of the models that took part in the AeroCom project. There is an interesting difference between the profiles from individual campaigns and more "climatological" datasets. For instance, compared to spatially and temporally localized campaigns, the model simulates a more continuous decline in both total

  4. Aerosol light scattering measurements as a function of relative humidity.

    Science.gov (United States)

    Day, D E; Malm, W C; Kreidenweis, S M

    2000-05-01

    The hygroscopic nature of atmospheric fine aerosol was investigated at a rural site in the Great Smoky Mountains National Park during July and August 1995. Passing the sample aerosol through an inlet, which housed an array of Perma Pure diffusion dryers, controlled the sample aerosol's relative humidity (RH). After conditioning the aerosol sample in the inlet, the light scattering coefficient and the aerosol size distribution were simultaneously measured. During this study, the conditioned aerosol's humidity ranged between 5% < RH < 95%. Aerosol response curves were produced using the ratio bspw/bspd; where bspw is the scattering coefficient measured at some RH greater than 20% and bspd is the scattering coefficient of the "dry" aerosol. For this work, any sample RH values below 15% were considered dry. Results of this investigation showed that the light scattering ratio increased continuously and smoothly over the entire range of relative humidity. The magnitude of the ratio at a particular RH value, however, varied considerably in time, particularly for RH values greater than approximately 60%. Curves of the scattering coefficient ratios as a function of RH were generated for each day and compared to the average 12-hour chemical composition of the aerosol. This comparison showed that for any particular RH value the ratio was highest during time periods of high sulfate concentrations and lowest during time periods of high soil or high organic carbon concentrations.

  5. Black carbon aerosol mixing state, organic aerosols and aerosol optical properties over the UK

    Science.gov (United States)

    McMeeking, G. R.; Morgan, W. T.; Flynn, M.; Highwood, E. J.; Turnbull, K.; Haywood, J.; Coe, H.

    2011-05-01

    Black carbon (BC) aerosols absorb sunlight thereby leading to a positive radiative forcing and a warming of climate and can also impact human health through their impact on the respiratory system. The state of mixing of BC with other aerosol species, particularly the degree of internal/external mixing, has been highlighted as a major uncertainty in assessing its radiative forcing and hence its climate impact, but few in situ observations of mixing state exist. We present airborne single particle soot photometer (SP2) measurements of refractory BC (rBC) mass concentrations and mixing state coupled with aerosol composition and optical properties measured in urban plumes and regional pollution over the UK. All data were obtained using instrumentation flown on the UK's BAe-146-301 large Atmospheric Research Aircraft (ARA) operated by the Facility for Airborne Atmospheric Measurements (FAAM). We measured sub-micron aerosol composition using an aerosol mass spectrometer (AMS) and used positive matrix factorization to separate hydrocarbon-like (HOA) and oxygenated organic aerosols (OOA). We found a higher number fraction of thickly coated rBC particles in air masses with large OOA relative to HOA, higher ozone-to-nitrogen oxides (NOx) ratios and large concentrations of total sub-micron aerosol mass relative to rBC mass concentrations. The more ozone- and OOA-rich air masses were associated with transport from continental Europe, while plumes from UK cities had higher HOA and NOx and fewer thickly coated rBC particles. We did not observe any significant change in the rBC mass absorption efficiency calculated from rBC mass and light absorption coefficients measured by a particle soot absorption photometer despite observing significant changes in aerosol composition and rBC mixing state. The contributions of light scattering and absorption to total extinction (quantified by the single scattering albedo; SSA) did change for different air masses, with lower SSA observed in

  6. Black carbon aerosol mixing state, organic aerosols and aerosol optical properties over the United Kingdom

    Science.gov (United States)

    McMeeking, G. R.; Morgan, W. T.; Flynn, M.; Highwood, E. J.; Turnbull, K.; Haywood, J.; Coe, H.

    2011-09-01

    Black carbon (BC) aerosols absorb sunlight thereby leading to a positive radiative forcing and a warming of climate and can also impact human health through their impact on the respiratory system. The state of mixing of BC with other aerosol species, particularly the degree of internal/external mixing, has been highlighted as a major uncertainty in assessing its radiative forcing and hence its climate impact, but few in situ observations of mixing state exist. We present airborne single particle soot photometer (SP2) measurements of refractory BC (rBC) mass concentrations and mixing state coupled with aerosol composition and optical properties measured in urban plumes and regional pollution over the United Kingdom. All data were obtained using instrumentation flown on the UK's BAe-146-301 large Atmospheric Research Aircraft (ARA) operated by the Facility for Airborne Atmospheric Measurements (FAAM). We measured sub-micron aerosol composition using an aerosol mass spectrometer (AMS) and used positive matrix factorization to separate hydrocarbon-like (HOA) and oxygenated organic aerosols (OOA). We found a higher number fraction of thickly coated rBC particles in air masses with large OOA relative to HOA, higher ozone-to-nitrogen oxides (NOx) ratios and large concentrations of total sub-micron aerosol mass relative to rBC mass concentrations. The more ozone- and OOA-rich air masses were associated with transport from continental Europe, while plumes from UK cities had higher HOA and NOx and fewer thickly coated rBC particles. We did not observe any significant change in the rBC mass absorption efficiency calculated from rBC mass and light absorption coefficients measured by a particle soot absorption photometer despite observing significant changes in aerosol composition and rBC mixing state. The contributions of light scattering and absorption to total extinction (quantified by the single scattering albedo; SSA) did change for different air masses, with lower SSA

  7. Black carbon aerosol mixing state, organic aerosols and aerosol optical properties over the United Kingdom

    Directory of Open Access Journals (Sweden)

    G. R. McMeeking

    2011-09-01

    Full Text Available Black carbon (BC aerosols absorb sunlight thereby leading to a positive radiative forcing and a warming of climate and can also impact human health through their impact on the respiratory system. The state of mixing of BC with other aerosol species, particularly the degree of internal/external mixing, has been highlighted as a major uncertainty in assessing its radiative forcing and hence its climate impact, but few in situ observations of mixing state exist. We present airborne single particle soot photometer (SP2 measurements of refractory BC (rBC mass concentrations and mixing state coupled with aerosol composition and optical properties measured in urban plumes and regional pollution over the United Kingdom. All data were obtained using instrumentation flown on the UK's BAe-146-301 large Atmospheric Research Aircraft (ARA operated by the Facility for Airborne Atmospheric Measurements (FAAM. We measured sub-micron aerosol composition using an aerosol mass spectrometer (AMS and used positive matrix factorization to separate hydrocarbon-like (HOA and oxygenated organic aerosols (OOA. We found a higher number fraction of thickly coated rBC particles in air masses with large OOA relative to HOA, higher ozone-to-nitrogen oxides (NOx ratios and large concentrations of total sub-micron aerosol mass relative to rBC mass concentrations. The more ozone- and OOA-rich air masses were associated with transport from continental Europe, while plumes from UK cities had higher HOA and NOx and fewer thickly coated rBC particles. We did not observe any significant change in the rBC mass absorption efficiency calculated from rBC mass and light absorption coefficients measured by a particle soot absorption photometer despite observing significant changes in aerosol composition and rBC mixing state. The contributions of light scattering and absorption to total extinction (quantified by the single scattering albedo; SSA did change for

  8. Cloud Droplet Size and Liquid Water Path Retrievals From Zenith Radiance Measurements: Examples From the Atmospheric Radiation Measurement Program and the Aerosol Robotic Network

    Science.gov (United States)

    Chiu, J. C.; Marshak, A.; Huang, C.-H.; Varnai, T.; Hogan, R. J.; Giles, D. M.; Holben, B. N.; Knyazikhin, Y.; O'Connor, E. J.; Wiscombe, W. J.

    2012-01-01

    The ground-based Atmospheric Radiation Measurement Program (ARM) and NASA Aerosol Robotic Network (AERONET) routinely monitor clouds using zenith radiances at visible and near-infrared wavelengths. Using the transmittance calculated from such measurements, we have developed a new retrieval method for cloud effective droplet size and conducted extensive tests for non-precipitating liquid water clouds. The underlying principle is to combine a water-absorbing wavelength (i.e. 1640 nm) with a nonwater-absorbing wavelength for acquiring information on cloud droplet size and optical depth. For simulated stratocumulus clouds with liquid water path less than 300 g/sq m and horizontal resolution of 201m, the retrieval method underestimates the mean effective radius by 0.8 m, with a root-mean-squared error of 1.7 m and a relative deviation of 13 %. For actual observations with a liquid water path less than 450 gm.2 at the ARM Oklahoma site during 2007-2008, our 1.5 min-averaged retrievals are generally larger by around 1 m than those from combined ground-based cloud radar and microwave radiometer at a 5min temporal resolution. We also compared our retrievals to those from combined shortwave flux and microwave observations for relatively homogeneous clouds, showing that the bias between these two retrieval sets is negligible, but the error of 2.6 m and the relative deviation of 22% are larger than those found in our simulation case. Finally, the transmittance-based cloud effective droplet radii agree to better than 11% with satellite observations and have a negative bias of 1 m. Overall, the retrieval method provides reasonable cloud effective radius estimates, which can enhance the cloud products of both ARM and AERONET.

  9. CALIPSO lidar ratio retrieval over the ocean.

    Science.gov (United States)

    Josset, Damien; Rogers, Raymond; Pelon, Jacques; Hu, Yongxiang; Liu, Zhaoyan; Omar, Ali; Zhai, Peng-Wang

    2011-09-12

    We are demonstrating on a few cases the capability of CALIPSO to retrieve the 532 nm lidar ratio over the ocean when CloudSat surface scattering cross section is used as a constraint. We are presenting the algorithm used and comparisons with the column lidar ratio retrieved by the NASA airborne high spectral resolution lidar. For the three cases presented here, the agreement is fairly good. The average CALIPSO 532 nm column lidar ratio bias is 13.7% relative to HSRL, and the relative standard deviation is 13.6%. Considering the natural variability of aerosol microphysical properties, this level of accuracy is significant since the lidar ratio is a good indicator of aerosol types. We are discussing dependencies of the accuracy of retrieved aerosol lidar ratio on atmospheric aerosol homogeneity, lidar signal to noise ratio, and errors in the optical depth retrievals. We are obtaining the best result (bias 7% and standard deviation around 6%) for a nighttime case with a relatively constant lidar ratio (in the vertical) indicative of homogeneous aerosol type.

  10. Characteristics of Aerosol Transport from Asia to the West Coast of North America

    Science.gov (United States)

    Brock, C. A.; Bahreini, R.; Middlebrook, A. M.; Atlas, E. L.; Blake, D. R.; Brioude, J.; Cooper, O. R.; de Gouw, J. A.; Holloway, J. S.; Lack, D. A.; Langridge, J. M.; Meinardi, S.; Nowak, J. B.; Peischl, J.; Perring, A.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Schwarz, J. P.; Spackman, J. R.; Trainer, M.; Trytko, J.; Warneke, C.

    2010-12-01

    During the CalNex field program of May and June 2010, the NOAA WP-3D aircraft observed several layers of enhanced trace gas mixing ratios and aerosol concentrations at altitudes ranging from 1 to 4 km over southern and central California. The submicron aerosol composition within these layers was dominated by partially neutralized sulfate, while nitrate, organic matter and black carbon were only minor constituents. The particle layers were associated with trace gases, such as benzene and sulfur dioxide, consistent with anthropogenic fossil fuel emissions, and were not associated with enhancements of the biomass burning tracer acetonitrile. The particle size distribution was dominated by a single accumulation mode that is characteristic of a well aged aerosol. Transport modeling indicates an Asian source for these layers of pollution. Dew point temperatures within the layers were less than -15 degrees Celsius, indicating desiccation by precipitation during transport. Taken together, these observations are consistent with those from earlier studies in which was diagnosed the removal of primary and organic particles by precipitation scavenging during uplift from the polluted Asian boundary layer into the free troposphere. Oxidation of residual sulfur dioxide that remained following transport through the cloud system may have resulted in the observed sulfate-rich aerosol. The repeated observation of such layers suggests that wet scavenging frequently modifies the chemical and optical characteristics of aerosols emitted in urban regions in Asia and transported in the free troposphere across the Pacific.

  11. Influences of in-cloud aerosol scavenging parameterizations on aerosol concentrations and wet deposition in ECHAM5-HAM

    Directory of Open Access Journals (Sweden)

    B. Croft

    2009-10-01

    Full Text Available A diagnostic nucleation scavenging scheme, which determines stratiform cloud scavenging ratios for both aerosol mass and number distributions, based on cloud droplet, and ice crystal number concentrations, is introduced into the ECHAM5-HAM global climate model. This is coupled with a size-dependent in-cloud impaction scavenging parameterization for both cloud droplet-aerosol, and ice crystal-aerosol collisions. Sensitivity studies are presented, which compare aerosol concentrations, and deposition between a variety of in-cloud scavenging approaches, including prescribed fractions, several diagnostic schemes, and a prognostic aerosol cloud processing treatment that passes aerosol in-droplet and in-ice crystal concentrations between model time steps. For one sensitivity study, assuming 100% of the in-cloud aerosol is scavenged into the cloud droplets and ice crystals, the annual global mean accumulation mode number burden is decreased by 65%, relative to a simulation with prognostic aerosol cloud processing. Diagnosing separate nucleation scavenging ratios for aerosol number and mass distributions, as opposed to equating the aerosol mass scavenging to the number scavenging ratios, reduces the annual global mean sulfate burden by near to 10%. The annual global mean sea salt burden is 30% lower for the diagnostic approach, which does not carry aerosol in-droplet and in-crystal concentrations between model time-steps as compared to the prognostic scheme. Implementation of in-cloud impaction scavenging reduced the annual, global mean black carbon burden by 30% for the prognostic aerosol cloud processing scheme. Better agreement with observations of black carbon profiles from aircraft (changes near to one order of magnitude for mixed phase clouds, 210Pb surface layer concentrations and wet deposition, and the geographic distribution of aerosol optical depth are found for the new diagnostic scavenging as compared to prescribed ratio

  12. Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gopalakrishnan, V.; Subramanian, V.; Baskaran, R.; Venkatraman, B. [Radiation Impact Assessment Section, Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

    2015-07-15

    Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging.

  13. Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments

    Science.gov (United States)

    Gopalakrishnan, V.; Subramanian, V.; Baskaran, R.; Venkatraman, B.

    2015-07-01

    Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging.

  14. Simultaneous aerosol measurements of unusual aerosol enhancement in troposphere over Syowa Station, Antarctica

    Directory of Open Access Journals (Sweden)

    K. Hara

    2013-10-01

    Full Text Available Unusual aerosol enhancement is often observed at Syowa Station, Antarctica during winter through spring. Simultaneous aerosol measurements near the surface and in the upper atmosphere were conducted twice using a ground-based optical particle counter, a balloon-borne optical particle counter, and micro-pulse LIDAR (MPL in August and September 2012. During 13–15 August, aerosol enhancement occurred immediately after a storm condition. A high backscatter ratio and aerosol concentrations were observed from the surface to ca. 2.5 km over Syowa Station. Clouds appeared occasionally at the top of aerosol-enhanced layer during the episode. Aerosol enhancement was terminated on 15 August by strong winds caused by a cyclone's approach. In the second case on 5–7 September, aerosol number concentrations in Dp > 0.3 μm near the surface reached > 104 L−1 at about 15:00 UT on 5 September in spite of calm wind conditions, whereas MPL measurement exhibited aerosols were enhanced at about 04:00 UT at 1000–1500 m above Syowa Station. The aerosol enhancement occurred near the surface–ca. 4 km. In both cases, air masses with high aerosol enhancement below 2.5–3 km were transported mostly from the boundary layer over the sea-ice area. In addition, air masses at 3–4 km in the second case came from the boundary layer over the open-sea area. This air mass history strongly suggests that dispersion of sea-salt particles from the sea-ice surface contributes considerably to the aerosol enhancement in the lower free troposphere (about 3 km and that the release of sea-salt particles from the ocean surface engenders high aerosol concentrations in the free troposphere (3–4 km.

  15. Aerosol typing - key information from aerosol studies

    Science.gov (United States)

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

    2016-04-01

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

  16. Aerosol Transport Over Equatorial Africa

    Science.gov (United States)

    Gatebe, C. K.; Tyson, P. D.; Annegarn, H. J.; Kinyua, A. M.; Piketh, S.; King, M.; Helas, G.

    1999-01-01

    Long-range and inter-hemispheric transport of atmospheric aerosols over equatorial Africa has received little attention so far. Most aerosol studies in the region have focussed on emissions from rain forest and savanna (both natural and biomass burning) and were carried out in the framework of programs such as DECAFE (Dynamique et Chimie Atmospherique en Foret Equatoriale) and FOS (Fires of Savanna). Considering the importance of this topic, aerosols samples were measured in different seasons at 4420 meters on Mt Kenya and on the equator. The study is based on continuous aerosol sampling on a two stage (fine and coarse) streaker sampler and elemental analysis by Particle Induced X-ray Emission. Continuous samples were collected for two seasons coinciding with late austral winter and early austral spring of 1997 and austral summer of 1998. Source area identification is by trajectory analysis and sources types by statistical techniques. Major meridional transports of material are observed with fine-fraction silicon (31 to 68 %) in aeolian dust and anthropogenic sulfur (9 to 18 %) being the major constituents of the total aerosol loading for the two seasons. Marine aerosol chlorine (4 to 6 %), potassium (3 to 5 %) and iron (1 to 2 %) make up the important components of the total material transport over Kenya. Minimum sulfur fluxes are associated with recirculation of sulfur-free air over equatorial Africa, while maximum sulfur concentrations are observed following passage over the industrial heartland of South Africa or transport over the Zambian/Congo Copperbelt. Chlorine is advected from the ocean and is accompanied by aeolian dust recirculating back to land from mid-oceanic regions. Biomass burning products are transported from the horn of Africa. Mineral dust from the Sahara is transported towards the Far East and then transported back within equatorial easterlies to Mt Kenya. This was observed during austral summer and coincided with the dying phase of 1997/98 El

  17. Offer/Acceptance Ratio.

    Science.gov (United States)

    Collins, Mimi

    1997-01-01

    Explores how human resource professionals, with above average offer/acceptance ratios, streamline their recruitment efforts. Profiles company strategies with internships, internal promotion, cooperative education programs, and how to get candidates to accept offers. Also discusses how to use the offer/acceptance ratio as a measure of program…

  18. Aerosol mobility size spectrometer

    Science.gov (United States)

    Wang, Jian; Kulkarni, Pramod

    2007-11-20

    A device for measuring aerosol size distribution within a sample containing aerosol particles. The device generally includes a spectrometer housing defining an interior chamber and a camera for recording aerosol size streams exiting the chamber. The housing includes an inlet for introducing a flow medium into the chamber in a flow direction, an aerosol injection port adjacent the inlet for introducing a charged aerosol sample into the chamber, a separation section for applying an electric field to the aerosol sample across the flow direction and an outlet opposite the inlet. In the separation section, the aerosol sample becomes entrained in the flow medium and the aerosol particles within the aerosol sample are separated by size into a plurality of aerosol flow streams under the influence of the electric field. The camera is disposed adjacent the housing outlet for optically detecting a relative position of at least one aerosol flow stream exiting the outlet and for optically detecting the number of aerosol particles within the at least one aerosol flow stream.

  19. Squeezing of Ion Populations and Peaks in Traveling Wave Ion Mobility Separations and Structures for Lossless Ion Manipulations using Compression Ratio Ion Mobility Programming

    Energy Technology Data Exchange (ETDEWEB)

    Garimella, Venkata BS; Hamid, Ahmed M.; Deng, Liulin; Ibrahim, Yehia M.; Webb, Ian K.; Baker, Erin M.; Prost, Spencer A.; Norheim, Randolph V.; Anderson, Gordon A.; Smith, Richard D.

    2016-11-02

    In this work, we report an approach for spatial and temporal gas phase ion population manipulation, and demonstrate its application for the collapse of the ion distributions in ion mobility (IM) separations into tighter packets providing higher sensitivity measurements in conjunction with mass spectrometry (MS). We do this for ions moving from a conventionally traveling wave (TW)-driven region to a region where the TW is intermittently halted or ‘stuttered’. This approach causes the ion packets spanning a number of TW-created traveling traps (TT) to be redistributed into fewer TT, resulting in spatial compression. The degree of spatial compression is controllable and determined by the ratio of stationary time of the TW in the second region to its moving time. This compression ratio ion mobility programming (CRIMP) approach has been implemented using Structures for Lossless Ion Manipulations (SLIM) in conjunction with MS. CRIMP with the SLIM-MS platform is shown to provide increased peak intensities, reduced peak widths, and improved S/N ratios with MS detection. CRIMP also provides a foundation for extremely long path length and multi-pass IM separations in SLIM providing greatly enhanced IM resolution by reducing the detrimental effects of diffusional peak broadening due to increasing peak widths.

  20. On the implications of aerosol liquid water and phase separation for organic aerosol mass

    Science.gov (United States)

    Pye, Havala O. T.; Murphy, Benjamin N.; Xu, Lu; Ng, Nga L.; Carlton, Annmarie G.; Guo, Hongyu; Weber, Rodney; Vasilakos, Petros; Wyat Appel, K.; Hapsari Budisulistiorini, Sri; Surratt, Jason D.; Nenes, Athanasios; Hu, Weiwei; Jimenez, Jose L.; Isaacman-VanWertz, Gabriel; Misztal, Pawel K.; Goldstein, Allen H.

    2017-01-01

    Organic compounds and liquid water are major aerosol constituents in the southeast United States (SE US). Water associated with inorganic constituents (inorganic water) can contribute to the partitioning medium for organic aerosol when relative humidities or organic matter to organic carbon (OM / OC) ratios are high such that separation relative humidities (SRH) are below the ambient relative humidity (RH). As OM / OC ratios in the SE US are often between 1.8 and 2.2, organic aerosol experiences both mixing with inorganic water and separation from it. Regional chemical transport model simulations including inorganic water (but excluding water uptake by organic compounds) in the partitioning medium for secondary organic aerosol (SOA) when RH > SRH led to increased SOA concentrations, particularly at night. Water uptake to the organic phase resulted in even greater SOA concentrations as a result of a positive feedback in which water uptake increased SOA, which further increased aerosol water and organic aerosol. Aerosol properties, such as the OM / OC and hygroscopicity parameter (κorg), were captured well by the model compared with measurements during the Southern Oxidant and Aerosol Study (SOAS) 2013. Organic nitrates from monoterpene oxidation were predicted to be the least water-soluble semivolatile species in the model, but most biogenically derived semivolatile species in the Community Multiscale Air Quality (CMAQ) model were highly water soluble and expected to contribute to water-soluble organic carbon (WSOC). Organic aerosol and SOA precursors were abundant at night, but additional improvements in daytime organic aerosol are needed to close the model-measurement gap. When taking into account deviations from ideality, including both inorganic (when RH > SRH) and organic water in the organic partitioning medium reduced the mean bias in SOA for routine monitoring networks and improved model performance compared to observations from SOAS. Property updates from

  1. Aerosol classification using airborne High Spectral Resolution Lidar measurements – methodology and examples

    Directory of Open Access Journals (Sweden)

    S. P. Burton

    2012-01-01

    Full Text Available The NASA Langley Research Center (LaRC airborne High Spectral Resolution Lidar (HSRL on the NASA B200 aircraft has acquired extensive datasets of aerosol extinction (532 nm, aerosol optical depth (AOD (532 nm, backscatter (532 and 1064 nm, and depolarization (532 and 1064 nm profiles during 18 field missions that have been conducted over North America since 2006. The lidar measurements of aerosol intensive parameters (lidar ratio, depolarization, backscatter color ratio, and spectral depolarization ratio are shown to vary with location and aerosol type. A methodology based on observations of known aerosol types is used to qualitatively classify the extensive set of HSRL aerosol measurements into eight separate types. Several examples are presented showing how the aerosol intensive parameters vary with aerosol type and how these aerosols are classified according to this new methodology. The HSRL-based classification reveals vertical variability of aerosol types during the NASA ARCTAS field experiment conducted over Alaska and northwest Canada during 2008. In two examples derived from flights conducted during ARCTAS, the HSRL classification of biomass burning smoke is shown to be consistent with aerosol types derived from coincident airborne in situ measurements of particle size and composition. The HSRL retrievals of AOD and inferences of aerosol types are used to apportion AOD to aerosol type; results of this analysis are shown for several experiments.

  2. Aerosol distribution apparatus

    Science.gov (United States)

    Hanson, W.D.

    An apparatus for uniformly distributing an aerosol to a plurality of filters mounted in a plenum, wherein the aerosol and air are forced through a manifold system by means of a jet pump and released into the plenum through orifices in the manifold. The apparatus allows for the simultaneous aerosol-testing of all the filters in the plenum.

  3. The impact of biogenic carbon sources on aerosol absorption in Mexico City

    Science.gov (United States)

    Marley, N. A.; Gaffney, J. S.; Tackett, M.; Sturchio, N. C.; Heraty, L.; Martinez, N.; Hardy, K. D.; Marchany-Rivera, A.; Guilderson, T.; MacMillan, A.; Steelman, K.

    2009-03-01

    In order to determine the wavelength dependence of fine (C-4 plants) in 2006. A direct comparison of the fM values, stable carbon isotope ratios, and aerosol AAEs suggested that the wavelength dependence of the aerosol absorption was controlled by the biogenically derived aerosol components.

  4. Aerosols of Mongolian arid area

    Science.gov (United States)

    Golobokova, L.; Marinayte, I.; Zhamsueva, G.

    2012-04-01

    Sampling was performed in July-August 2005-2010 at Station Sain Shand (44°54'N, 110°07'E) in the Gobi desert (1000 m a.s.l.), West Mongolia. Aerosol samples were collected with a high volume sampler PM 10 (Andersen Instruments Inc., USA) onto Whatman-41 filters. The substance was extracted from the filters by de-ionized water. The solution was screened through an acetate-cellulose filter with 0.2 micron pore size. Ions of ammonium, sodium, potassium, magnesium, and calcium, as well as sulphate ions, nitrate ions, hydrocarbonate, chloride ions were determined in the filtrate by means of an atomic adsorption spectrometer Carl Zeiss Jena (Germany), a high performance liquid chromatographer «Milichrome A-02» (Russia), and an ionic chromatographer ICS-3000 (Dionex, USA). The PAH fraction was separated from aerosol samples using hexane extraction at room temperature under UV environment. The extract was concentrated to 0.1-0.2 ml and analysed by a mass-spectrometer "Agilent, GC 6890, MSD 5973 Network". Analysis of concentrations of aerosols components, their correlation ratios, and meteorological modeling show that the main factor affecting chemical composition of aerosols is a flow of contaminants transferred by air masses to the sampling area mainly from the south and south-east, as well as wind conditions of the area, dust storms in particular. Sulphate, nitrate, and ammonium are major ions in aerosol particles at Station Sain Shand. Dust-borne aerosol is known to be a sorbent for both mineral and organic admixtures. Polycyclic aromatic hydrocarbons (PAH) being among superecotoxicants play an important role among resistant organic substances. PAH concentrations were determined in the samples collected in 2010. All aerosol samples contained dominant PAHs with 5-6 benzene rings ( (benze(k)fluoranthen, benze(b)flouranthen, benze(a)pyren, benze(?)pyren, perylene, benze(g,h,i)perylene, and indene(1,2,3-c,d)pyrene). Their total quantity varied between 42 and 90

  5. Climatology of Aerosol Optical Properties in Southern Africa

    Science.gov (United States)

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

    2011-01-01

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

  6. Separating mixtures of aerosol types in airborne High Spectral Resolution Lidar data

    Directory of Open Access Journals (Sweden)

    S. P. Burton

    2013-09-01

    Full Text Available Knowledge of aerosol type is important for source attribution and for determining the magnitude and assessing the consequences of aerosol radiative forcing. However, atmospheric aerosol is frequently not a single pure type, but instead occurs as a mixture of types, and this mixing affects the optical and radiative properties of the aerosol. This paper extends the work of earlier researchers by using the aerosol intensive parameters measured by the NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1 to develop a comprehensive and unified set of rules for characterizing the external mixing of several key aerosol intensive parameters: extinction-to-backscatter ratio (i.e. lidar ratio, backscatter color ratio, and depolarization ratio. We present the mixing rules in a particularly simple form that leads easily to mixing rules for the covariance matrices that describe aerosol distributions, rather than just scalar values of measured parameters. These rules can be applied to infer mixing ratios from the lidar-observed aerosol parameters, even for cases without significant depolarization. We demonstrate our technique with measurement curtains from three HSRL-1 flights which exhibit mixing between two aerosol types, urban pollution plus dust, marine plus dust, and smoke plus marine. For these cases, we infer a time-height cross-section of mixing ratio along the flight track, and partition aerosol extinction into portions attributed to the two pure types.

  7. Separating mixtures of aerosol types in airborne High Spectral Resolution Lidar data

    Science.gov (United States)

    Burton, S. P.; Vaughan, M. A.; Ferrare, R. A.; Hostetler, C. A.

    2014-02-01

    Knowledge of aerosol type is important for determining the magnitude and assessing the consequences of aerosol radiative forcing, and can provide useful information for source attribution studies. However, atmospheric aerosol is frequently not a single pure type, but instead occurs as a mixture of types, and this mixing affects the optical and radiative properties of the aerosol. This paper extends the work of earlier researchers by using the aerosol intensive parameters measured by the NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1) to develop a comprehensive and unified set of rules for characterizing the external mixing of several key aerosol intensive parameters: extinction-to-backscatter ratio (i.e., lidar ratio), backscatter color ratio, and depolarization ratio. We present the mixing rules in a particularly simple form that leads easily to mixing rules for the covariance matrices that describe aerosol distributions, rather than just single values of measured parameters. These rules can be applied to infer mixing ratios from the lidar-observed aerosol parameters, even for cases without significant depolarization. We demonstrate our technique with measurement curtains from three HSRL-1 flights which exhibit mixing between two aerosol types, urban pollution plus dust, marine plus dust, and smoke plus marine. For these cases, we infer a time-height cross-section of extinction mixing ratio along the flight track, and partition aerosol extinction into portions attributed to the two pure types.

  8. A new method for estimating aerosol mass flux in the urban surface layer using LAS technology

    Science.gov (United States)

    Yuan, Renmin; Luo, Tao; Sun, Jianning; Liu, Hao; Fu, Yunfei; Wang, Zhien

    2016-04-01

    Atmospheric aerosol greatly influences human health and the natural environment, as well as the weather and climate system. Therefore, atmospheric aerosol has attracted significant attention from society. Despite consistent research efforts, there are still uncertainties in understanding its effects due to poor knowledge about aerosol vertical transport caused by the limited measurement capabilities of aerosol mass vertical transport flux. In this paper, a new method for measuring atmospheric aerosol vertical transport flux is developed based on the similarity theory of surface layer, the theory of light propagation in a turbulent atmosphere, and the observations and studies of the atmospheric equivalent refractive index (AERI). The results show that aerosol mass flux can be linked to the real and imaginary parts of the atmospheric equivalent refractive index structure parameter (AERISP) and the ratio of aerosol mass concentration to the imaginary part of the AERI. The real and imaginary parts of the AERISP can be measured based on the light-propagation theory. The ratio of the aerosol mass concentration to the imaginary part of the AERI can be measured based on the measurements of aerosol mass concentration and visibility. The observational results show that aerosol vertical transport flux varies diurnally and is related to the aerosol spatial distribution. The maximum aerosol flux during the experimental period in Hefei City was 0.017 mg m-2 s-1, and the mean value was 0.004 mg m-2 s-1. The new method offers an effective way to study aerosol vertical transport in complex environments.

  9. Spectral optical properties of long-range transport Asian dust and pollution aerosols over Northeast Asia in 2007 and 2008

    Directory of Open Access Journals (Sweden)

    J. Jung

    2010-06-01

    Full Text Available As a part of the IGAC (International Global Atmospheric Chemistry Mega-cities program, aerosol physical and optical properties were continuously measured from March 2007 to March 2008 at an urban site (37.57° N, 126.94° E in Seoul, Korea. Spectral optical properties of long-range transported Asian dust and pollution aerosols have been investigated based on the year long measurement data. Optically measured black carbon/thermally measured elemental carbon (BC/EC ratio showed clear monthly variation with high values in summer and low values in winter mainly due to the enhancement of light attenuation by the internal mixing of EC. Novel approach has been suggested to retrieve the spectral light absorption coefficient (babs from Aethalometer raw data by using BC/EC ratio. Mass absorption efficiency, σabs (=babs/EC at 550 nm was determined to be 9.0±1.3, 8.9±1.5, 9.5±2.0, and 10.3±1.7 m2 g−1 in spring, summer, fall, and winter, respectively with an annual mean of 9.4±1.8 m2 g−1. Threshold values to classify severe haze events were suggested in this study. Increasing trend of aerosol single scattering albedo (SSA with wavelength was observed during Asian dust events while little spectral dependence of SSA was observed during long-range transport pollution (LTP events. Satellite aerosol optical thickness (AOT and Hysplit air mass backward trajectory analyses as well as chemical analysis were performed to characterize the dependence of spectral optical properties on aerosol type. Results from this study can provide useful information for studies on regional air quality and aerosol's effects on climate change.

  10. Aerosol Absorption Measurements in MILAGRO.

    Science.gov (United States)

    Gaffney, J. S.; Marley, N. A.; Arnott, W. P.; Paredes-Miranda, L.; Barnard, J. C.

    2007-12-01

    to carbonyl- and nitro- functional groups on conjugated and aromatic organic structures (e.g. PAH, and terpene derived products). Using 12-hour fine (0.1-1.0 micron) aerosol samples collected in the field on quartz filters, uv/vis and infrared spectra were obtained in the laboratory using integrating spheres and diffuse reflectance spectroscopy, respectively. An inter-comparison of the "real-time" measurements made by the photo-acoustic, aethalometer and MAAP techniques have been described. In addition, the in situ aethalometer (seven-channel) results are compared with continuous integrating sphere uv-visible spectra to examine the angstrom absorption coefficient variance. These results will be briefly overviewed and the specific posters detailing these results will be highlighted highlighted. This work was performed as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City under the support of the Atmospheric Science Program. "This researchwas supported by the Office of Science (BER), U. S. Department of Energy, Grant No. DE-FG02-07ER64329.

  11. Sensitivity of aerosol retrieval over snow surfaces

    Science.gov (United States)

    Seidel, F. C.; Painter, T. H.

    2011-12-01

    Significant amounts of black carbon and dust aerosols are transported to and accumulated in snowpacks of mountain ranges around the globe. The direct climate forcing of these particles is increasingly understood, whereas its indirect radiative forcing due to snow albedo and snow cover changes is still under investigation. In-situ and new remote sensing techniques are used to estimate snowpack properties from local to regional scales. Nevertheless, orbital and suborbital Earth observation data are difficult to analyze due to high spatial variability of the snowpack in rugged terrain. In addition, changes in atmospheric turbidity significantly complicate the estimation of snow cover characteristics and requires prior retrieval of optical and microphysical aerosol properties. Unfortunately, most aerosol retrieval techniques work only over dark surfaces. We therefore present a study on the sensitivity of aerosol optical depth (AOD) retrieval over snow surfaces. Radiative transfer calculations show that the sensitivity to surface spectral albedo depends strongly on the aerosol single scattering albedo (ratio of scattering efficiency to total extinction efficiency). Absorbing aerosol types (e.g. soot) provide a relatively good AOD retrieval sensitivity for very bright surfaces. The findings provide a basis for the development of future techniques and algorithms, which are able to concurrently retrieve snow and aerosol properties using remote sensing data. We explore these sensitivities with synthetic data and a time series of imaging spectrometer data, in situ spectral irradiance measurements, and sunphotometer measurements of AOD in the mountains of the Upper Colorado River Basin, USA. Ultimately, this research is important to map and better understand regional influences of aerosol and climate forcings on the cryosphere and water cycle in mountainous and other cold regions.

  12. Coarse mode aerosols in the High Arctic

    Science.gov (United States)

    Baibakov, K.; O'Neill, N. T.; Chaubey, J. P.; Saha, A.; Duck, T. J.; Eloranta, E. W.

    2014-12-01

    Fine mode (submicron) aerosols in the Arctic have received a fair amount of scientific attention in terms of smoke intrusions during the polar summer and Arctic haze pollution during the polar winter. Relatively little is known about coarse mode (supermicron) aerosols, notably dust, volcanic ash and sea salt. Asian dust is a regular springtime event whose optical and radiative forcing effects have been fairly well documented at the lower latitudes over North America but rarely reported for the Arctic. Volcanic ash, whose socio-economic importance has grown dramatically since the fear of its effects on aircraft engines resulted in the virtual shutdown of European civil aviation in the spring of 2010 has rarely been reported in the Arctic in spite of the likely probability that ash from Iceland and the Aleutian Islands makes its way into the Arctic and possibly the high Arctic. Little is known about Arctic sea salt aerosols and we are not aware of any literature on the optical measurement of these aerosols. In this work we present preliminary results of the combined sunphotometry-lidar analysis at two High Arctic stations in North America: PEARL (80°N, 86°W) for 2007-2011 and Barrow (71°N,156°W) for 2011-2014. The multi-years datasets were analyzed to single out potential coarse mode incursions and study their optical characteristics. In particular, CIMEL sunphotometers provided coarse mode optical depths as well as information on particle size and refractive index. Lidar measurements from High Spectral Resolution lidars (AHSRL at PEARL and NSHSRL at Barrow) yielded vertically resolved aerosol profiles and gave an indication of particle shape and size from the depolarization ratio and color ratio profiles. Additionally, we employed supplementary analyses of HYSPLIT backtrajectories, OMI aerosol index, and NAAPS (Navy Aerosol Analysis and Prediction System) outputs to study the spatial context of given events.

  13. Black carbon in aerosol during BIBLE B

    Science.gov (United States)

    Liley, J. Ben; Baumgardner, D.; Kondo, Y.; Kita, K.; Blake, D. R.; Koike, M.; Machida, T.; Takegawa, N.; Kawakami, S.; Shirai, T.; Ogawa, T.

    2003-02-01

    The Biomass Burning and Lightning Experiment (BIBLE) A and B campaigns over the tropical western Pacific during springtime deployed a Gulfstream-II aircraft with systems to measure ozone and numerous precursor species. Aerosol measuring systems included a MASP optical particle counter, a condensation nucleus (CN) counter, and an absorption spectrometer for black carbon. Aerosol volume was very low in the middle and upper troposphere during both campaigns, and during BIBLE A, there was little aerosol enhancement in the boundary layer away from urban areas. In BIBLE B, there was marked aerosol enhancement in the lowest 3 km of the atmosphere. Mixing ratios of CN in cloud-free conditions in the upper troposphere were in general higher than in the boundary layer, indicating new particle formation from gaseous precursors. High concentrations of black carbon were observed during BIBLE B, with mass loadings up to 40 μg m-3 representing as much as one quarter of total aerosol mass. Strong correlations with hydrocarbon enhancement allow the determination of a black carbon emission ratio for the fires at that time. Expressed as elemental carbon, it is about 0.5% of carbon dioxide and 6% of carbon monoxide emissions from the same fires, comparable to methane production, and greater than that of other hydrocarbons.

  14. HTR-PROTEUS Pebble Bed Experimental Program Cores 1, 1A, 2, and 3: Hexagonal Close Packing with a 1:2 Moderator-to-Fuel Pebble Ratio

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Barbara H. Dolphin; James W. Sterbentz; Luka Snoj; Igor Lengar; Oliver Köberl

    2012-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. Four benchmark experiments were evaluated in this report: Cores 1, 1A, 2, and 3. These core configurations represent the hexagonal close packing (HCP) configurations of the HTR-PROTEUS experiment with a moderator-to-fuel pebble ratio of 1:2. Core 1 represents the only configuration utilizing ZEBRA control rods. Cores 1A, 2, and 3 use withdrawable, hollow, stainless steel control rods. Cores 1 and 1A are similar except for the use of different control rods; Core 1A also has one less layer of pebbles (21 layers instead of 22). Core 2 retains the first 16 layers of pebbles from Cores 1 and 1A and has 16 layers of moderator pebbles stacked above the fueled layers. Core 3 retains the first 17 layers of pebbles but has polyethylene rods inserted between pebbles to simulate water ingress. The additional partial pebble layer (layer 18) for Core 3 was not included as it was used for core operations and not the reported critical configuration. Cores 1, 1A, 2, and 3 were determined to be acceptable benchmark experiments.

  15. HTR-PROTEUS Pebble Bed Experimental Program Cores 1, 1A, 2, and 3: Hexagonal Close Packing with a 1:2 Moderator-to-Fuel Pebble Ratio

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Barbara H. Dolphin; James W. Sterbentz; Luka Snoj; Igor Lengar; Oliver Köberl

    2013-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. Four benchmark experiments were evaluated in this report: Cores 1, 1A, 2, and 3. These core configurations represent the hexagonal close packing (HCP) configurations of the HTR-PROTEUS experiment with a moderator-to-fuel pebble ratio of 1:2. Core 1 represents the only configuration utilizing ZEBRA control rods. Cores 1A, 2, and 3 use withdrawable, hollow, stainless steel control rods. Cores 1 and 1A are similar except for the use of different control rods; Core 1A also has one less layer of pebbles (21 layers instead of 22). Core 2 retains the first 16 layers of pebbles from Cores 1 and 1A and has 16 layers of moderator pebbles stacked above the fueled layers. Core 3 retains the first 17 layers of pebbles but has polyethylene rods inserted between pebbles to simulate water ingress. The additional partial pebble layer (layer 18) for Core 3 was not included as it was used for core operations and not the reported critical configuration. Cores 1, 1A, 2, and 3 were determined to be acceptable benchmark experiments.

  16. Aerosol MTF revisited

    Science.gov (United States)

    Kopeika, Norman S.; Zilberman, Arkadi; Yitzhaky, Yitzhak

    2014-05-01

    Different views of the significance of aerosol MTF have been reported. For example, one recent paper [OE, 52(4)/2013, pp. 046201] claims that the aerosol MTF "contrast reduction is approximately independent of spatial frequency, and image blur is practically negligible". On the other hand, another recent paper [JOSA A, 11/2013, pp. 2244-2252] claims that aerosols "can have a non-negligible effect on the atmospheric point spread function". We present clear experimental evidence of common significant aerosol blur and evidence that aerosol contrast reduction can be extremely significant. In the IR, it is more appropriate to refer to such phenomena as aerosol-absorption MTF. The role of imaging system instrumentation on such MTF is addressed too.

  17. Optical characterization of continental and biomass-burning aerosols over Bozeman, Montana: A case study of the aerosol direct effect

    Science.gov (United States)

    Nehrir, Amin R.; Repasky, Kevin S.; Reagan, John A.; Carlsten, John L.

    2011-11-01

    Atmospheric aerosol optical properties were observed from 21 to 27 September 2009 over Bozeman, Montana, during a transitional period in which background polluted rural continental aerosols and well-aged biomass-burning aerosols were the dominant aerosol types of extremely fresh biomass-burning aerosols resulting from forest fires burning in the northwestern United States and Canada. Aerosol optical properties and relative humidity profiles were retrieved using an eye-safe micropulse water vapor differential absorption lidar (DIAL) (MP-DIAL), a single-channel backscatter lidar, a CIMEL solar radiometer as part of the Aerosol Robotic Network (AERONET), a ground-based integrating nephelometer, and aerosol products from Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua. Aerosol optical depths (AODs) measured during the case study ranged between 0.03 and 0.17 (0.015 and 0.075) at 532 nm (830 nm) as episodic combinations of fresh and aged biomass-burning aerosols dominated the optical depth of the pristinely clean background air. Here, a pristinely clean background refers to very low AOD conditions, not that the aerosol scattering and absorption properties are necessarily representative of a clean aerosol type. Diurnal variability in the aerosol extinction to backscatter ratio (Sa) of the background atmosphere derived from the two lidars, which ranged between 55 and 95 sr (50 and 90 sr) at 532 nm (830 nm), showed good agreement with retrievals from AERONET sun and sky measurements over the same time period but were consistently higher than some aerosol models had predicted. Sa measured during the episodic smoke events ranged on average from 60 to 80 sr (50 to 70 sr) at 532 nm (830 nm) while the very fresh biomass-burning aerosols were shown to exhibit significantly lower Sa ranging between 20 and 40 sr. The shortwave direct radiative forcing that was due to the intrusion of biomass-burning aerosols was calculated to be on average -10 W/m2 and was

  18. Research on buildings impacting on aerosol diffusing in urban area using remote sensing

    Institute of Scientific and Technical Information of China (English)

    YANG Sheng-tian; YANG Zhi-feng; MAO Xian-qiang; ZHU Qi-jiang

    2004-01-01

    Employing remote sensing method to interpret the building volumetric ratio and aerosol status in Guangzhou, China. The relation between them and identified characteristics of their spatial distribution was analyzed. Results showed that building density and aerosol status are strongly correlated. It is indicated that the resistance of building to aerosol diffusing is one of factors influencing air pollution in urban area. On the basis of calculated results, building voluminous ratio of 5.6 is taken as the threshold impacting on aerosol diffusing, so the building voluminous ratio of Guangzhou should be limited to less than 5.6 in order to alleviate air pollution.

  19. Aerosols Science and Technology

    CERN Document Server

    Agranovski, Igor

    2011-01-01

    This self-contained handbook and ready reference examines aerosol science and technology in depth, providing a detailed insight into this progressive field. As such, it covers fundamental concepts, experimental methods, and a wide variety of applications, ranging from aerosol filtration to biological aerosols, and from the synthesis of carbon nanotubes to aerosol reactors.Written by a host of internationally renowned experts in the field, this is an essential resource for chemists and engineers in the chemical and materials disciplines across multiple industries, as well as ideal supplementary

  20. Cloud condensation nuclei (CCN) activity of aliphatic amine secondary aerosol

    Science.gov (United States)

    Tang, X.; Price, D.; Praske, E.; Vu, D. N.; Purvis-Roberts, K.; Silva, P. J.; Cocker, D. R., III; Asa-Awuku, A.

    2014-06-01

    Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g., hydroxyl radical and nitrate radical). The particle can contain both secondary organic aerosol (SOA) and inorganic salts. The ratio of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN) activity. SOA formed from trimethylamine (TMA) and butylamine (BA) reactions with hydroxyl radical (OH) is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ, ≤ 0.25). Secondary aerosol formed from the tertiary aliphatic amine (TMA) with N2O5 (source of nitrate radical, NO3) contains less volatile compounds than the primary aliphatic amine (BA) aerosol. As relative humidity (RH) increases, inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR) ideal mixing rules. The humid BA + N2O5 aerosol products were found to be very sensitive to the temperature at which the measurements were made within the streamwise continuous-flow thermal gradient CCN counter; κ ranges from 0.4 to 0.7 dependent on the instrument supersaturation (ss) settings. The variance of the measured aerosol κ values indicates that simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems' κ ranges within 0.2 systems.

  1. Optical closure study on light-absorbing aerosols

    Science.gov (United States)

    Petzold, Andreas; Bundke, Ulrich; Freedman, Andrew; Onasch, Timothy B.; Massoli, Paola; Andrews, Elizabeth; Hallar, Anna G.

    2014-05-01

    The in situ measurement of atmospheric aerosol optical properties is an important component of quantifying climate change. In particular, the in-situ measurement of the aerosol single-scattering albedo (SSA), which is the ratio of aerosol scattering to aerosol extinction, is identified as a key challenge in atmospheric sciences and climate change research. Ideally, the complete set of aerosol optical properties is measured through optical closure studies which simultaneous measure aerosol extinction, scattering and absorption coefficients. The recent development of new optical instruments have made real-time in situ optical closure studies attainable, however, many of these instruments are state-of-the-art but not practical for routine monitoring. In our studies we deployed a suit of well-established and recently developed instruments including the cavity attenuated phase shift (CAPS) method for aerosol light extinction, multi-angle absorption photometer (MAAP) and particle soot absorption photometer (PSAP) for aerosol light absorption, and an integrating nephelometer (NEPH) for aerosol light scattering measurements. From these directly measured optical properties we calculated light absorption from extinction minus scattering (difference method), light extinction from scattering plus absorption, and aerosol single-scattering albedo from combinations CAPS + MAAP, NEPH + PSAP, NEPH + MAAP, CAPS + NEPH. Closure studies were conducted for laboratory-generated aerosols composed of various mixtures of black carbon (Regal 400R pigment black, Cabot Corp.) and ammonium sulphate, urban aerosol (Billerica, MA), and background aerosol (Storm Peak Lab.). Key questions addressed in our closure studies are: (1) how well can we measure aerosol light absorption by various methods, and (2) how well can we measure the aerosol single-scattering albedo by various instrument combinations? In particular we investigated (3) whether the combination of a CAPS and NEPH provides a reasonable

  2. Airborne high spectral resolution lidar observation of pollution aerosol during EUCAARI-LONGREX

    Directory of Open Access Journals (Sweden)

    S. Groß

    2012-10-01

    Full Text Available Airborne high spectral resolution lidar observations over Europe during the EUCAARI field experiment in May 2008 are analysed with respect to spatial distribution and optical properties of continental pollution aerosol. Continental aerosol is characterized by its depolarisation and lidar ratio. Mean values of 6%±1% for the particle linear depolarisation ratio, and 56 sr±6 sr for the lidar ratio were found for pollution aerosol. Both, lidar ratio and depolarisation ratio at 532 nm show virtually no variations for all analysed days during the measurement campaign.

  3. Long term aerosol and trace gas measurements in Central Amazonia

    Science.gov (United States)

    Artaxo, Paulo; Barbosa, Henrique M. J.; Ferreira de Brito, Joel; Carbone, Samara; Rizzo, Luciana V.; Andreae, Meinrat O.; Martin, Scot T.

    2016-04-01

    The central region of the Amazonian forest is a pristine region in terms of aerosol and trace gases concentrations. In the wet season, Amazonia is actually one of the cleanest continental region we can observe on Earth. A long term observational program started 20 years ago, and show important features of this pristine region. Several sites were used, between then ATTO (Amazon Tall Tower Observatory) and ZF2 ecological research site, both 70-150 Km North of Manaus, receiving air masses that traveled over 1500 km of pristine tropical forests. The sites are GAW regional monitoring stations. Aerosol chemical composition (OC/EC and trace elements) is being analysed using filters for fine (PM2.5) and coarse mode aerosol as well as Aerodyne ACSM (Aerosol Chemical Speciation Monitors). VOCs are measured using PTR-MS, while CO, O3 and CO2 are routinely measured. Aerosol absorption is being studied with AE33 aethalometers and MAAP (Multi Angle Absorption Photometers). Aerosol light scattering are being measured at several wavelengths using TSI and Ecotech nephelometers. Aerosol size distribution is determined using scanning mobility particle sizer at each site. Lidars measure the aerosol column up to 12 Km providing the vertical profile of aerosol extinction. The aerosol column is measures using AERONET sun photometers. In the wet season, organic aerosol comprises 75-85% of fine aerosol, and sulfate and nitrate concentrations are very low (1-3 percent). Aerosols are dominated by biogenic primary particles as well as SOA from biogenic precursors. Black carbon in the wet season accounts for 5-9% of fine mode aerosol. Ozone in the wet season peaks at 10-12 ppb at the middle of the day, while carbon monoxide averages at 50-80 ppb. Aerosol optical thickness (AOT) is a low 0.05 to 0.1 at 550 nm in the wet season. Sahara dust transport events sporadically enhance the concentration of soil dust aerosols and black carbon. In the dry season (August-December), long range transported

  4. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORE 4: RANDOM PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Leland M. Montierth

    2014-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. One benchmark experiment was evaluated in this report: Core 4. Core 4 represents the only configuration with random pebble packing in the HTR-PROTEUS series of experiments, and has a moderator-to-fuel pebble ratio of 1:1. Three random configurations were performed. The initial configuration, Core 4.1, was rejected because the method for pebble loading, separate delivery tubes for the moderator and fuel pebbles, may not have been completely random; this core loading was rejected by the experimenters. Cores 4.2 and 4.3 were loaded using a single delivery tube, eliminating the possibility for systematic ordering effects. The second and third cores differed slightly in the quantity of pebbles loaded (40 each of moderator and fuel pebbles), stacked height of the pebbles in the core cavity (0.02 m), withdrawn distance of the stainless steel control rods (20 mm), and withdrawn distance of the autorod (30 mm). The 34 coolant channels in the upper axial reflector and the 33 coolant channels in the lower axial reflector were open. Additionally, the axial graphite fillers used in all other HTR-PROTEUS configurations to create a 12-sided core cavity were not used in the randomly packed cores. Instead, graphite fillers were placed on the cavity floor, creating a funnel-like base, to discourage ordering

  5. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORE 4: RANDOM PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Leland M. Montierth

    2013-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. One benchmark experiment was evaluated in this report: Core 4. Core 4 represents the only configuration with random pebble packing in the HTR-PROTEUS series of experiments, and has a moderator-to-fuel pebble ratio of 1:1. Three random configurations were performed. The initial configuration, Core 4.1, was rejected because the method for pebble loading, separate delivery tubes for the moderator and fuel pebbles, may not have been completely random; this core loading was rejected by the experimenters. Cores 4.2 and 4.3 were loaded using a single delivery tube, eliminating the possibility for systematic ordering effects. The second and third cores differed slightly in the quantity of pebbles loaded (40 each of moderator and fuel pebbles), stacked height of the pebbles in the core cavity (0.02 m), withdrawn distance of the stainless steel control rods (20 mm), and withdrawn distance of the autorod (30 mm). The 34 coolant channels in the upper axial reflector and the 33 coolant channels in the lower axial reflector were open. Additionally, the axial graphite fillers used in all other HTR-PROTEUS configurations to create a 12-sided core cavity were not used in the randomly packed cores. Instead, graphite fillers were placed on the cavity floor, creating a funnel-like base, to discourage ordering

  6. Seasonal variability of tropospheric aerosols in Rome

    Science.gov (United States)

    Ciardini, Virginia; Di Iorio, Tatiana; Di Liberto, Luca; Tirelli, Cecilia; Casasanta, Giampietro; di Sarra, Alcide; Fiocco, Giorgio; Fuà, Daniele; Cacciani, Marco

    2012-11-01

    two classes show largest differences during Spring and Summer. The extinction for non-dust profiles decreases monotonically with altitude throughout the year, except in Summer. Conversely, the aerosol extinction coefficient shows a relative minimum at the lowest sounded altitude, always except in winter, for class 1 cases. A winter maximum of the aerosol is evidently present in winter in the lower troposphere. Using the MFRSR optical depth and the lidar profiles, the lidar ratio was derived. The overall average lidar ratio is 58 sr.

  7. Aerosol physical properties and their impact on climate change processes

    Science.gov (United States)

    Strzalkowska, Agata; Zielinski, Tymon; Petelski, Tomasz; Makuch, Przemyslaw; Pakszys, Paulina; Markuszewski, Piotr; Piskozub, Jacek; Drozdowska, Violetta; Gutowska, Dorota; Rozwadowska, Anna

    2013-04-01

    Characterizing aerosols involves the specification of not only their spatial and temporal distributions but their multi-component composition, particle size distribution and physical properties as well. Due to their light attenuation and scattering properties, aerosols influence radiance measured by satellite for ocean color remote sensing. Studies of marine aerosol production and transport are important for many earth sciences such as cloud physics, atmospheric optics, environmental pollution studies, and interaction between ocean and atmosphere. It was one of the reasons for the growth in the number of research programs dealing with marine aerosols. Sea salt aerosols are among the most abundant components of the atmospheric aerosol, and thus it exerts a strong influence on radiation, cloud formation, meteorology and chemistry of the marine atmosphere. An accurate understanding and description of these mechanisms is crucial to modeling climate and climate change. This work provides information on combined aerosol studies made with lidars and sun photometers onboard the ship and in different coastal areas. We concentrate on aerosol optical thickness and its variations with aerosol advections into the study area. We pay special attention to the problem of proper data collection and analyses techniques. We showed that in order to detect the dynamics of potential aerosol composition changes it is necessary to use data from different stations where measurements are made using the same techniques. The combination of such information with air mass back-trajectories and data collected at stations located on the route of air masses provides comprehensive picture of aerosol variations in the study area both vertically and horizontally. Acknowledgements: The support for this study was provided by the project Satellite Monitoring of the Baltic Sea Environment - SatBałtyk founded by European Union through European Regional Development Fund contract No. POIG 01

  8. Transgenic increase in N-3/n-6 Fatty Acid ratio reduces maternal obesity-associated inflammation and limits adverse developmental programming in mice.

    Directory of Open Access Journals (Sweden)

    Margaret J R Heerwagen

    Full Text Available Maternal and pediatric obesity has risen dramatically over recent years, and is a known predictor of adverse long-term metabolic outcomes in offspring. However, which particular aspects of obese pregnancy promote such outcomes is less clear. While maternal obesity increases both maternal and placental inflammation, it is still unknown whether this is a dominant mechanism in fetal metabolic programming. In this study, we utilized the Fat-1 transgenic mouse to test whether increasing the maternal n-3/n-6 tissue fatty acid ratio could reduce the consequences of maternal obesity-associated inflammation and thereby mitigate downstream developmental programming. Eight-week-old WT or hemizygous Fat-1 C57BL/6J female mice were placed on a high-fat diet (HFD or control diet (CD for 8 weeks prior to mating with WT chow-fed males. Only WT offspring from Fat-1 mothers were analyzed. WT-HFD mothers demonstrated increased markers of infiltrating adipose tissue macrophages (P<0.02, and a striking increase in 12 serum pro-inflammatory cytokines (P<0.05, while Fat1-HFD mothers remained similar to WT-CD mothers, despite equal weight gain. E18.5 Fetuses from WT-HFD mothers had larger placentas (P<0.02, as well as increased placenta and fetal liver TG deposition (P<0.01 and P<0.02, respectively and increased placental LPL TG-hydrolase activity (P<0.02, which correlated with degree of maternal insulin resistance (r = 0.59, P<0.02. The placentas and fetal livers from Fat1-HFD mothers were protected from this excess placental growth and fetal-placental lipid deposition. Importantly, maternal protection from excess inflammation corresponded with improved metabolic outcomes in adult WT offspring. While the offspring from WT-HFD mothers weaned onto CD demonstrated increased weight gain (P<0.05, body and liver fat (P<0.05 and P<0.001, respectively, and whole body insulin resistance (P<0.05, these were prevented in WT offspring from Fat1-HFD mothers. Our results

  9. DARE : Dedicated Aerosols Retrieval Experiment

    NARCIS (Netherlands)

    Smorenburg, K.; Courrèges-Lacoste, G.B.; Decae, R.; Court, A.J.; Leeuw, G. de; Visser, H.

    2004-01-01

    At present there is an increasing interest in remote sensing of aerosols from space because of the large impact of aerosols on climate, earth observation and health. TNO has performed a study aimed at improving aerosol characterisation using a space based instrument and state-of-the-art aerosol retr

  10. Aerosol measurements at the Southern Great Plains Site: Design and surface installation

    Energy Technology Data Exchange (ETDEWEB)

    Leifer, R.; Knuth, R.H.; Guggenheim, S.F.; Albert, B. [Department of Energy, New York, NY (United States)

    1996-04-01

    To impropve the predictive capabilities of the Atmospheric Radiation Measurements (ARM) program radiation models, measurements of awserosol size distributions, condensation particle concentrations, aerosol scattering coefficients at a number of wavelenghts, and the aerosol absorption coefficients are needed at the Southern Great Plains (SGP) site. Alos, continuous measurements of ozone concnetrations are needed for model validation. The environmental Measuremenr Laboratory (EMK) has the responsibility to establish the surface aerosol measurements program at the SGP site. EML has designed a special sampling manifold.

  11. Studies of aerosols advected to coastal areas

    Science.gov (United States)

    Zielinski, T.; Petelski, T.; Makuch, P.; Strzalkowska, A.; Ponczkowska, A.; Drozdowska, V.; Gutowska, D.; Kowalczyk, J.; Darecki, M.; Piskozub, J.

    2012-04-01

    Characterizing aerosols involves the specification of not only their spatial and temporal distributions but their multi-component composition, particle size distribution and physical properties as well. Due to their light attenuation and scattering properties, aerosols influence radiance measured by satellite for ocean color remote sensingmaking them highly relevant for the ocean color atmospheric correction. This paper presents the results of the studies of aerosol optical properties measured using lidars and sun photometers. We describe two case studies of the combined measurements made in two coastal zones, in Crete in 2006and in Rozewie on the Baltic Sea in 2009. The combination of lidar and sun photometer measurements provides comprehensive information on both the total aerosol optical thickness in the entire atmosphere as well as the vertical structure of aerosol optical properties. Combination of such information with air mass back-trajectories and data collected at stations located on the route of air masses provides complete picture of the aerosol variations in the study area both vertically and horizontally. We show that such combined studies are especially important in the coastal areas. Additionally, aerosol particle direct and indirect radiative effects have been identified as key uncertainties for the prediction of the future global climate. This research has been made within the framework of the NASA/AERONET Program and Polish National Grants 1276/B/P01/2010/38, PBW 1283/B/P01/2010/38, POLAR-AOD, NN 306315536 and Satellite Monitoring of the Baltic Sea Environment - SatBałtyk funded by the European Union through European Regional Development Fund contract no. POIG 01.01.02-22-011/09.

  12. TIGERZ I: Aerosols, Monsoon and Synergism

    Science.gov (United States)

    Holben, B. N.; Tripathi, S. N.; Schafer, J. S.; Giles, D. M.; Eck, T. F.; Sinyuk, A.; Smirnov, A.; Krishnmoorthy, K.; Sorokin, M. G.; Newcomb, W. W.; Tran, A. K.; Sikka, D. R.; Goloub, P.; O'Neill, N. T.; Abboud, I.; Randles, C.; Niranjan, K.; Dumka, U. C.; Tiwari, S.; Devara, P. C.; Kumar, S.; Remer, L. A.; Kleidman, R.; Martins, J. V.; Kahn, R.

    2008-12-01

    The Indo-Gangetic Plain of northern India encompasses a vast complex of urban and rural landscapes, cultures that serve as anthropogenic sources of fine mode aerosols mixed with coarse mode particles transported from SW Asia. The summer monsoon and fall Himalayan snowmelt provide the agricultural productivity to sustain an extremely high population density whose affluence is increasing. Variations in the annual monsoon precipitation of 10% define drought, normal and a wet season; the net effects on the ecosystems and quality of life can be dramatic. Clearly investigation of anthropogenic and natural aerosol impacts on the monsoon, either through the onset, monsoon breaks or end points are a great concern to understand and ultimately mitigate. Many national and international field campaigns are being planned and conducted to study various aspects of the Asian monsoon and some coordinated under the Asian Monsoon Years (AMY) umbrella. A small program called TIGERZ conducted during the pre-monsoon of 2008 in North Central India can serve as a model for contributing significant resources to existing field programs while meeting immediate project goals. This poster will discuss preliminary results of the TIGERZ effort including ground-based measurements of aerosol properties in the I-G from AERONET and synergism with various Indian programs, satellite observations and aerosol modeling efforts.

  13. Aerosol Indices Derived from MODIS Data for Indicating Aerosol-Induced Air Pollution

    Directory of Open Access Journals (Sweden)

    Junliang He

    2014-02-01

    Full Text Available Aerosol optical depth (AOD is a critical variable in estimating aerosol concentration in the atmosphere, evaluating severity of atmospheric pollution, and studying their impact on climate. With the assistance of the 6S radiative transfer model, we simulated apparent reflectancein relation to AOD in each Moderate Resolution Imaging Spectroradiometer (MODIS waveband in this study. The closeness of the relationship was used to identify the most and least sensitive MODIS wavebands. These two bands were then used to construct three aerosol indices (difference, ratio, and normalized difference for estimating AOD quickly and effectively. The three indices were correlated, respectively, with in situ measured AOD at the Aerosol Robotic NETwork (AERONET Lake Taihu, Beijing, and Xianghe stations. It is found that apparent reflectance of the blue waveband (band 3 is the most sensitive to AOD while the mid-infrared wavelength (band 7 is the least sensitive. The difference aerosol index is the most accurate in indicating aerosol-induced atmospheric pollution with a correlation coefficient of 0.585, 0.860, 0.685, and 0.333 at the Lake Taihu station, 0.721, 0.839, 0.795, and 0.629 at the Beijing station, and 0.778, 0.782, 0.837, and 0.643 at the Xianghe station in spring, summer, autumn and winter, respectively. It is concluded that the newly proposed difference aerosol index can be used effectively to study the level of aerosol-induced air pollution from MODIS satellite imagery with relative ease.

  14. MSA in Beijing aerosol

    Institute of Scientific and Technical Information of China (English)

    YUAN Hui; WANG Ying; ZHUANG Guoshun

    2004-01-01

    Methane sulphonate (MSA) and sulfate (SO42-), the main oxidation products of dimethyl sulfide (DMS), are the target of atmospheric chemistry study, as sulfate aerosol would have important impact on the global climate change. It is widely believed that DMS is mainly emitted from phytoplankton production in marine boundary layer (MBL), and MSA is usually used as the tracer of non-sea-salt sulfate (nss- SO42-) in marine and coastal areas (MSA/SO42- = 1/18). Many observations of MSA were in marine and coastal aerosols. To our surprise, MSA was frequently (>60%) detected in Beijing TSP, PM10, and PM2.5 aerosols, even in the samples collected during the dust storm period. The concentrations of MSA were higher than those measured in marine aerosols. Factor analysis, correlation analysis and meteorology analysis indicated that there was no obvious marine influence on Beijing aerosols. DMS from terrestrial emissions and dimethyl sulphoxide (DMSO) from industrial wastes could be the two possible precursors of MSA. Warm and low-pressure air masses and long time radiation were beneficial to the formation of MSA. Anthropogenic pollution from regional and local sources might be the dominant contributor to MSA in Beijing aerosol. This was the first report of MSA in aerosols collected in an inland site in China. This new finding would lead to the further study on the balance of sulfur in inland cities and its global biogeochemical cycle.

  15. Raman Lidar Measurements of Aerosol and Cloud Optical Properties in the Troposphere

    Institute of Scientific and Technical Information of China (English)

    WU Yonghua; HU Shunxing; QI Fudi; XU Jisheng; ZHOU Jun; HU Huanling

    2002-01-01

    A Raman lidar has been developed with photon counting technique. Aerosol and cloud extinction coefficients are derived by nitrogen (N2) molecular Raman scatter returns in the troposphere. Both backscatter coefficients and extinction-backscatter-ratios of aerosol and cloud are presented by simultaneously combining N2 Raman and Mie-Rayleigh returns of aerosol and molecule. Ratios of extinction to backscatter between 20 sr and 70 sr are usually found for aerosol, but less than 15 sr for mid-high altitude cloud in the troposphere.

  16. Thermodynamic characterization of Mexico City aerosol during MILAGRO 2006

    Directory of Open Access Journals (Sweden)

    C. Fountoukis

    2009-03-01

    Full Text Available Fast measurements of aerosol and gas-phase constituents coupled with the ISORROPIA-II thermodynamic equilibrium model are used to study the partitioning of semivolatile inorganic species and phase state of Mexico City aerosol sampled at the T1 site during the MILAGRO 2006 campaign. Overall, predicted semivolatile partitioning agrees well with measurements. PM2.5 is insensitive to changes in ammonia but is to acidic semivolatile species. For particle sizes up to 1μm diameter, semi-volatile partitioning requires 15–30 min to equilibrate; longer time is typically required during the night and early morning hours. Aerosol and gas-phase speciation always exhibits substantial temporal variability, so that aerosol composition measurements (bulk or size-resolved obtained over large integration periods are not reflective of its true state. When the aerosol sulfate-to-nitrate molar ratio is less than unity, predictions improve substantially if the aerosol is assumed to follow the deliquescent phase diagram. Treating crustal species as "equivalent sodium" (rather than explicitly in the thermodynamic equilibrium calculations introduces important biases in predicted aerosol water uptake, nitrate and ammonium; neglecting crustals further increases errors dramatically. This suggests that explicitly considering crustals in the thermodynamic calculations is required to accurately predict the partitioning and phase state of aerosols.

  17. Modal aerosol dynamics modeling

    Energy Technology Data Exchange (ETDEWEB)

    Whitby, E.R.; McMurry, P.H.; Shankar, U.; Binkowski, F.S.

    1991-02-01

    The report presents the governing equations for representing aerosol dynamics, based on several different representations of the aerosol size distribution. Analytical and numerical solution techniques for these governing equations are also reviewed. Described in detail is a computationally efficient numerical technique for simulating aerosol behavior in systems undergoing simultaneous heat transfer, fluid flow, and mass transfer in and between the gas and condensed phases. The technique belongs to a general class of models known as modal aerosol dynamics (MAD) models. These models solve for the temporal and spatial evolution of the particle size distribution function. Computational efficiency is achieved by representing the complete aerosol population as a sum of additive overlapping populations (modes), and solving for the time rate of change of integral moments of each mode. Applications of MAD models for simulating aerosol dynamics in continuous stirred tank aerosol reactors and flow aerosol reactors are provided. For the application to flow aerosol reactors, the discussion is developed in terms of considerations for merging a MAD model with the SIMPLER routine described by Patankar (1980). Considerations for incorporating a MAD model into the U.S. Environmental Protection Agency's Regional Particulate Model are also described. Numerical and analytical techniques for evaluating the size-space integrals of the modal dynamics equations (MDEs) are described. For multimodal logonormal distributions, an analytical expression for the coagulation integrals of the MDEs, applicable for all size regimes, is derived, and is within 20% of accurate numerical evaluation of the same moment coagulation integrals. A computationally efficient integration technique, based on Gauss-Hermite numerical integration, is also derived.

  18. Atmospheric aerosol monitoring at the Pierre Auger Observatory

    Energy Technology Data Exchange (ETDEWEB)

    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,; 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.

  19. Aerosol measurements at the south pole during 1987. Data report

    Energy Technology Data Exchange (ETDEWEB)

    Bodhaine, B.A.; Harris, J.M.

    1992-11-01

    The Climate Monitoring and Diagnostics Laboratory (CMDL) of the National Oceanic and Atmospheric Administration (NOAA) operates an atmospheric monitoring observatory at Amundsen-Scott Station, South Pole. The aerosol measurement program consists of the continuous measurement of condensation nuclei (CN) concentration and aerosol scattering extinction coefficient. During 1987, a special aerosol experiment was conducted that included filter samples for subsequent analysis by the proton induced x-ray emission technique, diffusion battery measurements for size information in the sub-0.1 micrometer size range, and aerosol absorption measurements using an aethalometer. Surface and upper air meteorological data were also available. The purpose of the report is to present all of the aerosol data obtained during 1987.

  20. Source apportionment of submicron organic aerosols at an urban site by linear unmixing of aerosol mass spectra

    Directory of Open Access Journals (Sweden)

    V. A. Lanz

    2006-11-01

    Full Text Available Submicron ambient aerosol was characterized in summer 2005 at an urban background site in Zurich, Switzerland, during a three-week measurement campaign. Highly time-resolved samples of non-refractory aerosol components were analyzed with an Aerodyne aerosol mass spectrometer (AMS. Positive matrix factorization (PMF was used for the first time for AMS data to identify the main components of the total organic aerosol and their sources. The PMF retrieved factors were compared to measured reference mass spectra and were correlated with tracer species of the aerosol and gas phase measurements from collocated instruments. Six factors were found to explain virtually all variance in the data and could be assigned either to sources or to aerosol components such as oxygenated organic aerosol (OOA. Our analysis suggests that at the measurement site only a small (<10% fraction of organic PM1 originates from freshly emitted fossil fuel combustion. Other primary sources identified to be of similar or even higher importance are charbroiling (10–15% and wood burning (~10%, along with a minor source interpreted to be influenced by food cooking (6%. The fraction of all identified primary sources is considered as primary organic aerosol (POA. This interpretation is supported by calculated ratios of the modelled POA and measured primary pollutants such as elemental carbon (EC, NOx, and CO, which are in good agreement to literature values. A high fraction (60–69% of the measured organic aerosol mass is OOA which is interpreted mostly as secondary organic aerosol (SOA. This oxygenated organic aerosol can be separated into a highly aged fraction, OOA I, (40–50% with low volatility and a mass spectrum similar to fulvic acid, and a more volatile and probably less processed fraction, OOA II (on average 20%. This is the first publication of a multiple component analysis technique to AMS organic spectral data and also the first report of the

  1. Characterization of secondary aerosol and its extinction effects on visibility over the Pearl River Delta Region, China.

    Science.gov (United States)

    Deng, Xuejiao; Wu, Dui; Yu, Jianzhen; Lau, Alexis K H; Li, Fei; Tan, Haobo; Yuan, Zibing; Ng, Wai Man; Deng, Tao; Wu, Cheng; Zhou, Xiuji

    2013-09-01

    Aerosol samples collected from July 2007 to March 2008 were used to obtain major aerosol constituents in an urban location in the Pearl River Delta Region (PRD), China. The minimum organic carbon (OC)/elemental carbon (EC) ratio was used to calculate the primary and secondary organic carbon and the extinction effect of the secondary aerosol on visibility was estimated. As indicated in the analysis, the mass of secondary aerosol takes up 50% of the total mass of PM2.5; the OC/EC ratio is larger than 2 and there are significant characteristics of secondary aerosol generation; the levels of secondary OC are comparable with those of sulfate; and there is obvious enrichment of secondary aerosol on more polluted days. In a dry environment, the extinction weight is 59% for the secondary aerosol, while it is as high as 82% if the environment is highly humid (relative humidity [RH] = 95%). The hygroscopic growth of the aerosol can reduce visibility greatly; the secondary aerosol shares much larger quotas on more polluted days. For the Pearl River Delta (PRD), secondary aerosol and carbonaceous aerosol, especially secondary organic carbon (SOC), are a very acute problem; the study of the generating mechanism and sources for secondary aerosol is the key to the effort of controlling visibility in this region. The equation set forth in IMPROVE experiments can only be referenced but is not applicable to evaluate the extinction effect of individual aerosol components on visibility in the PRD region.

  2. Aerosol deposition in bends with turbulent flow

    Energy Technology Data Exchange (ETDEWEB)

    McFarland, A.R.; Gong, H.; Wente, W.B. [Texas A& M Univ., College Station, TX (United States)] [and others

    1997-08-01

    The losses of aerosol particles in bends were determined numerically for a broad range of design and operational conditions. Experimental data were used to check the validity of the numerical model, where the latter employs a commercially available computational fluid dynamics code for characterizing the fluid flow field and Lagrangian particle tracking technique for characterizing aerosol losses. Physical experiments have been conducted to examine the effect of curvature ratio and distortion of the cross section of bends. If it curvature ratio ({delta} = R/a) is greater than about 4, it has little effect on deposition, which is in contrast with the recommendation given in ANSI N13.1-1969 for a minimum curvature ratio of 10. Also, experimental results show that if the tube cross section is flattened by 25% or less, the flattening also has little effect on deposition. Results of numerical tests have been used to develop a correlation of aerosol penetration through a bend as a function of Stokes number (Stk), curvature ratio ({delta}) and the bend angle ({theta}). 17 refs., 10 figs., 2 tabs.

  3. Multiwavelength multistatic optical scattering for aerosol characterization

    Science.gov (United States)

    Brown, Andrea M.

    The main focus of this research is the development of a technique to remotely characterize aerosol properties, such as particle size distribution, concentration, and refractive index as a function of wavelength, through the analysis of optical scattering measurements. The proposed technique is an extension of the multistatic polarization ratio technique that has been developed by prior students at the Penn State Lidar Lab to include multiple wavelengths. This approach uses the ratio of polarized components of the scattering phase functions at multiple wavelengths across the visible region of the electromagnetic spectrum to extract the microphysical and optical properties of aerosols. The scattering intensities at each wavelength are vertically separated across the face of the imager using a transmission diffraction grating, so that scattering intensities for multiple wavelengths at many angles are available for analysis in a single image. The ratio of the scattering phase function intensities collected using parallel and perpendicular polarized light are formed for each wavelength and analysis of the ratio is used to determine the microphysical properties of the aerosols. One contribution of the present work is the development of an inversion technique based on a genetic algorithm that retrieves lognormal size distributions from scattering measurements by minimizing the squared error between measured polarization ratios and polarization ratios calculated using the Mie solution to Maxwell's equations. The opportunities and limitations of using the polarization ratio are explored, and a genetic algorithm is developed to retrieve single mode and trimodal lognormal size distributions from multiwavelength, angular scattering data. The algorithm is designed to evaluate particles in the diameter size range of 2 nm to 60 im, and uses 1,000 linear spaced diameters within this range to compute the modeled polarization ratio. The algorithm returns geometric mean radii and

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-04-01

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

  5. Optical properties of different aerosol types: seven years of combined Raman-elastic backscatter lidar measurements in Thessaloniki, Greece

    Directory of Open Access Journals (Sweden)

    E. Giannakaki

    2010-05-01

    Full Text Available We present our combined Raman/elastic backscatter lidar observations which were carried out at the EARLINET station of Thessaloniki, Greece, during the period 2001–2007. The largest optical depths are observed for Saharan dust and smoke aerosol particles. For local and continental polluted aerosols the measurements indicate high aerosol loads. However, measurements associated with the local path indicate enhanced aerosol load within the Planetary Boundary Layer. The lowest value of aerosol optical depth is observed for continental aerosols, from West directions with less free tropospheric contribution. The largest lidar ratios, of the order of 70 sr, are found for biomass burning aerosols. A significant and distinct correlation between lidar ratio and backscatter related Ångström exponent values were estimated for different aerosol categories. Scatter plot between lidar ratio values and Ångström exponent values for local and continental polluted aerosols does not show a significant correlation, with a large variation in both parameters possibly due to variable absorption characteristics of these aerosols. Finally for continental aerosols with west and northwest directions that follow downward movement when arriving at our site constantly low lidar ratios almost independent of size are found.

  6. Aerosols from biomass combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T.

    2001-07-01

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

  7. Emergency Protection from Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Cristy, G.A.

    2001-11-13

    Expedient methods were developed that could be used by an average person, using only materials readily available, to protect himself and his family from injury by toxic (e.g., radioactive) aerosols. The most effective means of protection was the use of a household vacuum cleaner to maintain a small positive pressure on a closed house during passage of the aerosol cloud. Protection factors of 800 and above were achieved.

  8. Characterizing the Vertical Distribution of Aerosols Over the ARM SGP Site

    Energy Technology Data Exchange (ETDEWEB)

    Richard Ferrare, Connor Flynn, David Turner

    2009-05-05

    This project focused on: 1) evaluating the performance of the DOE ARM SGP Raman lidar system in measuring profiles of water vapor and aerosols, and 2) the use of the Raman lidar measurements of aerosol and water vapor profiles for assessing the vertical distribution of aerosols and water vapor simulated by global transport models and examining diurnal variability of aerosols and water vapor. The highest aerosol extinction was generally observed close to the surface during the nighttime just prior to sunrise. The high values of aerosol extinction are most likely associated with increased scattering by hygroscopic aerosols, since the corresponding average relative humidity values were above 70%. After sunrise, relative humidity and aerosol extinction below 500 m decreased with the growth in the daytime convective boundary layer. The largest aerosol extinction for altitudes above 1 km occurred during the early afternoon most likely as a result of the increase in relative humidity. The water vapor mixing ratio profiles generally showed smaller variations with altitude between day and night. We also compared simultaneous measurements of relative humidity, aerosol extinction, and aerosol optical thickness derived from the ARM SGP Raman lidar and in situ instruments on board a small aircraft flown routinely over the ARM SGP site. In contrast, the differences between the CARL and IAP aerosol extinction measurements are considerably larger. Aerosol extinction derived from the IAP measurements is, on average, about 30-40% less than values derived from the Raman lidar. The reasons for this difference are not clear, but may be related to the corrections for supermicron scattering and relative humidity that were applied to the IAP data. The investigators on this project helped to set up a major field mission (2003 Aerosol IOP) over the DOE ARM SGP site. One of the goals of the mission was to further evaluate the aerosol and water vapor retrievals from this lidar system

  9. Optical properties of mixed aerosol layers over Japan derived with multi-wavelength Mie-Raman lidar system

    Science.gov (United States)

    Hara, Yukari; Nishizawa, Tomoaki; Sugimoto, Nobuo; Matsui, Ichiro; Pan, Xiaole; Kobayashi, Hiroshi; Osada, Kazuo; Uno, Itsushi

    2017-02-01

    Mixing state of aerosols and optical properties including lidar ratio, particle depolarization ratio, and Ångström exponent were investigated at Fukuoka in western Japan using a multi-wavelength Mie-Raman lidar (MMRL), various aerosol mass-concentration measurements, and a polarization optical particle counter during Winter-Spring 2015. Aerosol extinction coefficient, backscatter coefficient, and depolarization at 355 and 532 nm and attenuated backscatter coefficient at 1064 nm are obtained from the MMRL measurements. Ten aerosol episodes were classified into three categories (air pollution, mineral dust, and marine aerosol) based on aerosol mass-concentration measurements in the fine-mode (particle diameter Dplidar ratio for air pollution was 57±4 sr at 355 nm and 53±8 sr at 532 nm with Ångström exponent of 1.4±0.5. For mineral dust, a slightly high averaged lidar ratio (50±7 sr at 355 nm and 54±9 sr at 532 nm) was obtained with relatively high Ångström exponent of 0.8±0.3 owing to contributions from fine-mode particles (PMf). The mean particle depolarization ratios of 13±8% at 355 nm and 16±6% at 532 nm also suggest mixing of mineral dust and anthropogenic fine-mode aerosols. The lowest lidar ratio was obtained for marine case. Classification of aerosol types using the lidar ratio and particle depolarization ratio was conducted based on the results obtained in this study. The classified aerosol types almost corresponded to aerosol category obtained by previous studies. We found no remarkable correlation between the fraction of black carbon and the lidar ratio: this might be due to the complexity of the mixing state among various aerosols. The obtained lidar ratio was rather correlated with the ratio of PMf to PM10, representing the mixing state of fine- and coarse-mode particles.

  10. RACORO aerosol data processing

    Energy Technology Data Exchange (ETDEWEB)

    Elisabeth Andrews

    2011-10-31

    The RACORO aerosol data (cloud condensation nuclei (CCN), condensation nuclei (CN) and aerosol size distributions) need further processing to be useful for model evaluation (e.g., GCM droplet nucleation parameterizations) and other investigations. These tasks include: (1) Identification and flagging of 'splash' contaminated Twin Otter aerosol data. (2) Calculation of actual supersaturation (SS) values in the two CCN columns flown on the Twin Otter. (3) Interpolation of CCN spectra from SGP and Twin Otter to 0.2% SS. (4) Process data for spatial variability studies. (5) Provide calculated light scattering from measured aerosol size distributions. Below we first briefly describe the measurements and then describe the results of several data processing tasks that which have been completed, paving the way for the scientific analyses for which the campaign was designed. The end result of this research will be several aerosol data sets which can be used to achieve some of the goals of the RACORO mission including the enhanced understanding of cloud-aerosol interactions and improved cloud simulations in climate models.

  11. The Deconvolution of Aerosol Backscattered Optical Pulses to Obtain System-Independent Aerosol Signatures.

    Science.gov (United States)

    1981-06-01

    S. CONTRACT OR GRANT NUMBERI.) Dennis Mc~uire Michael/~Conner 2. PERFOMN ORGANIZATION NAME AND AOORESS I0. PROGRAM ELEMENT. PROJECT. TASKC Harry...tech- niques has shown that exellent results can be obtained in simple cases (where the aerosol is known to be uniformly distributed and to completely

  12. Patient's Guide to Aerosol Drug Delivery

    Science.gov (United States)

    ... Table of Contents Page Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 ................................................................ 1. Aerosol Drug Delivery: The Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Aerosol Drugs: The Major Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 3. Aerosol Drug Delivery Devices: Small-Volume Nebulizers . . . . . . . . . . . . .17 4. Aerosol Drug ...

  13. Ozone and aerosol distributions measured by airborne lidar during the 1988 Arctic Boundary Layer Experiment

    Science.gov (United States)

    Browell, Edward V.; Butler, Carolyn F.; Kooi, Susan A.

    1991-01-01

    Consideration is given to O3 and aerosol distributions measured from an aircraft using a DIAL system in order to study the sources and sinks of gases and aerosols over the tundra regions of Alaska during summer 1988. The tropospheric O3 budget over the Arctic was found to be strongly influenced by stratospheric intrusions. Regions of low aerosol scattering and enhanced O3 mixing ratios were usually correlated with descending air from the upper troposphere or lower stratosphere.

  14. Airborne studies of aerosol emissions from savanna fires in southern Africa: 2. Aerosol chemical composition

    Science.gov (United States)

    Andreae, M. O.; Andreae, T. W.; Annegarn, H.; Beer, J.; Cachier, H.; Le Canut, P.; Elbert, W.; Maenhaut, W.; Salma, I.; Wienhold, F. G.; Zenker, T.

    1998-12-01

    We investigated smoke emissions from fires in savanna, forest, and agricultural ecosystems by airborne sampling of plumes close to prescribed burns and incidental fires in southern Africa. Aerosol samples were collected on glass fiber filters and on stacked filter units, consisting of a Nuclepore prefilter for particles larger than ˜1-2 μm and a Teflon second filter stage for the submicron fraction. The samples were analyzed for soluble ionic components, organic carbon, and black carbon. Onboard the research aircraft, particle number and volume distributions as a function of size were determined with a laser-optical particle counter and the black carbon content of the aerosol with an aethalometer. We determined the emission ratios (relative to CO2 and CO) and emission factors (relative to the amount of biomass burnt) for the various aerosol constituents. The smoke aerosols were rich in organic and black carbon, the latter representing 10-30% of the aerosol mass. K+ and NH4+ were the dominant cationic species in the smoke of most fires, while Cl- and SO42- were the most important anions. The aerosols were unusually rich in Cl-, probably due to the high Cl content of the semiarid vegetation. Comparison of the element budget of the fuel before and after the fires shows that the fraction of the elements released during combustion is highly variable between elements. In the case of the halogen elements, almost the entire amount released during the fire is present in the aerosol phase, while in the case of C, N, and S, only a small proportion ends up as particulate matter. This suggests that the latter elements are present predominantly as gaseous species in the fresh fire plumes studied here.

  15. Aerosol generation by blower motors as a bias in assessing aerosol penetration into cabin filtration systems.

    Science.gov (United States)

    Heitbrink, William A; Collingwood, Scott

    2005-01-01

    In cabin filtration systems, blower motors pressurize a vehicle cabin with clean filtered air and recirculate air through an air-conditioning evaporator coil and a heater core. The exposure reduction offered by these cabins is evaluated by optical particle counters that measure size-dependent aerosol concentration inside and outside the cabin. The ratio of the inside-to-outside concentration is termed penetration. Blower motors use stationary carbon brushes to transmit an electrical current through a rotating armature that abrades the carbon brushes. This creates airborne dust that may affect experimental evaluations of aerosol penetration. To evaluate the magnitude of these dust emissions, blower motors were placed in a test chamber and operated at 12 and 13.5 volts DC. A vacuum cleaner drew 76 m3/hour (45 cfm) of air through HEPA filters, the test chamber, and through a 5 cm diameter pipe. An optical particle counter drew air through an isokinetic sampling probe and measured the size-dependent particle concentrations from 0.3 to 15 microm. The concentration of blower motor aerosol was between 2 x 10(5) and 1.8 x 10(6) particles/m3. Aerosol penetration into three stationary vehicles, two pesticide application vehicles and one tractor were measured at two conditions: low concentration (outside in the winter) and high concentration (inside repair shops and burning incense sticks used as a supplemental aerosol source). For particles smaller than 1 microm, the in-cabin concentrations can be explained by the blower motor emissions. For particles larger than 1 microm, other aerosol sources, such as resuspended dirt, are present. Aerosol generated by the operation of the blower motor and by other sources can bias the exposure reduction measured by optical particle counters.

  16. Absorption characteristics of aerosols over the northwestern region of India: Distinct seasonal signatures of biomass burning aerosols and mineral dust

    Science.gov (United States)

    Gogoi, Mukunda M.; Suresh Babu, S.; Krishna Moorthy, K.; Manoj, M. R.; Chaubey, Jai Prakash

    2013-07-01

    Continuous measurements of aerosol black carbon (BC) mass concentrations made over a period of 3 years from a semi-arid, near-coastal, remote and sparsely inhabited location along with satellite-based data of aerosol absorption index, optical depth and extinction profiles in western India are used to characterize the distinct nature of aerosols near the surface and in the free troposphere and their seasonality. Despite being far remote and sparsely inhabited, significant levels of BC are observed in the ambient during winter (1.45 ± 0.71 μg m-3) attributed to biomass burning aerosols, advected to the site from the north and west; while during summer the concentrations are far reduced (0.23 ± 0.11 μg m-3) and represent the apparent background concentrations. The spectral absorption coefficients suggest the BC during summer be mostly of fossil fuel combustions. The strong convective boundary layer dynamics produces significant diurnal variation during winter and modulates to a lesser extent the seasonal variation. Examination of aerosol (absorption) index from OMI data for the study period showed a seasonal pattern that is almost opposite to that seen at the surface; with high aerosol index in summer, showing a significant difference between the surface and columnar aerosol types in summer. MISR and MODIS-derived columnar AOD follow the OMI pattern. Analysis of the vertical profiles of aerosol extinction and volume depolarization ratio (VDR), derived from CALIPSO data indicates the presence of strong dust layers with VDR ˜ 0.3 in the altitude region 4-6 km, contributing to the high aerosol index in the OMI data, while the surface measurements show absorptive properties representing fossil fuel BC aerosols.

  17. Medicare Program; Revisions to Payment Policies Under the Physician Fee Schedule and Other Revisions to Part B for CY 2017; Medicare Advantage Bid Pricing Data Release; Medicare Advantage and Part D Medical Loss Ratio Data Release; Medicare Advantage Provider Network Requirements; Expansion of Medicare Diabetes Prevention Program Model; Medicare Shared Savings Program Requirements. Final rule.

    Science.gov (United States)

    2016-11-15

    This major final rule addresses changes to the physician fee schedule and other Medicare Part B payment policies, such as changes to the Value Modifier, to ensure that our payment systems are updated to reflect changes in medical practice and the relative value of services, as well as changes in the statute. This final rule also includes changes related to the Medicare Shared Savings Program, requirements for Medicare Advantage Provider Networks, and provides for the release of certain pricing data from Medicare Advantage bids and of data from medical loss ratio reports submitted by Medicare health and drug plans. In addition, this final rule expands the Medicare Diabetes Prevention Program model.

  18. Sensitivity of remote aerosol distributions to representation of cloud-aerosol interactions in a global climate model

    Directory of Open Access Journals (Sweden)

    H. Wang

    2013-01-01

    Full Text Available Many global aerosol and climate models, including the widely used Community Atmosphere Model version 5 (CAM5, have large biases in predicting aerosols in remote regions such as upper troposphere and high latitudes. In this study, we conduct CAM5 sensitivity simulations to understand the role of key processes associated with aerosol transformation and wet removal affecting the vertical and horizontal long-range transport of aerosols to the remote regions. Improvements are made to processes that are currently not well represented in CAM5, which are guided by surface and aircraft measurements together with results from a multi-scale aerosol-climate model (PNNL-MMF that explicitly represents convection and aerosol-cloud interactions at cloud-resolving scales. We pay particular attention to black carbon (BC due to its importance in the Earth system and the availability of measurements. We introduce into CAM5 a new unified scheme for convective transport and aerosol wet removal with explicit aerosol activation above convective cloud base. This new implementation reduces the excessive BC aloft to better simulate observed BC profiles that show decreasing mixing ratios in the mid- to upper-troposphere. After implementing this new unified convective scheme, we examine wet removal of submicron aerosols that occurs primarily through cloud processes. The wet removal depends strongly on the sub-grid scale liquid cloud fraction and the rate of conversion of liquid water to precipitation. These processes lead to very strong wet removal of BC and other aerosols over mid- to high latitudes during winter months. With our improvements, the Arctic BC burden has a10-fold (5-fold increase in the winter (summer months, resulting in a much better simulation of the BC seasonal cycle as well. Arctic sulphate and other aerosol species also increase but to a lesser extent. An explicit treatment of BC aging with slower aging assumptions produces an additional 30-fold (5-fold

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

    Science.gov (United States)

    Clancy, R. T.

    1986-01-01

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

  20. Physical metrology of aerosols; Metrologie physique des aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Boulaud, D.; Vendel, J. [CEA Saclay, 91 - Gif-sur-Yvette (France). Inst. de Protection et de Surete Nucleaire

    1996-12-31

    The various detection and measuring methods for aerosols are presented, and their selection is related to aerosol characteristics (size range, concentration or mass range), thermo-hydraulic conditions (carrier fluid temperature, pressure and flow rate) and to the measuring system conditions (measuring frequency, data collection speed, cost...). Methods based on aerosol dynamic properties (inertial, diffusional and electrical methods) and aerosol optical properties (localized and integral methods) are described and their performances and applications are compared

  1. Aerosol formation yields from the reaction of catechol with ozone

    Science.gov (United States)

    Coeur-Tourneur, Cécile; Tomas, Alexandre; Guilloteau, Angélique; Henry, Françoise; Ledoux, Frédéric; Visez, Nicolas; Riffault, Véronique; Wenger, John C.; Bedjanian, Yuri

    The formation of secondary organic aerosol from the gas-phase reaction of catechol (1,2-dihydroxybenzene) with ozone has been studied in two smog chambers. Aerosol production was monitored using a scanning mobility particle sizer and loss of the precursor was determined by gas chromatography and infrared spectroscopy, whilst ozone concentrations were measured using a UV photometric analyzer. The overall organic aerosol yield ( Y) was determined as the ratio of the suspended aerosol mass corrected for wall losses ( Mo) to the total reacted catechol concentrations, assuming a particle density of 1.4 g cm -3. Analysis of the data clearly shows that Y is a strong function of Mo and that secondary organic aerosol formation can be expressed by a one-product gas-particle partitioning absorption model. The aerosol formation is affected by the initial catechol concentration, which leads to aerosol yields ranging from 17% to 86%. The results of this work are compared to similar studies reported in the literature.

  2. The colors of biomass burning aerosols in the atmosphere

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2011-01-01

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

  4. The impact of geoengineering aerosols on stratospheric temperature and ozone

    Energy Technology Data Exchange (ETDEWEB)

    Heckendorn, P; Luo, B P; Rozanov, E; Schraner, M; Peter, T [Institute for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich (Switzerland); Weisenstein, D [AER, Lexington, MA (United States); Fueglistaler, S [DAMTP, University of Cambridge (United Kingdom); Thomason, L W, E-mail: patricia.heckendorn@env.ethz.c [NASA Langley Research Center, Hampton, VA (United States)

    2009-10-15

    Anthropogenic greenhouse gas emissions are warming the global climate at an unprecedented rate. Significant emission reductions will be required soon to avoid a rapid temperature rise. As a potential interim measure to avoid extreme temperature increase, it has been suggested that Earth's albedo be increased by artificially enhancing stratospheric sulfate aerosols. We use a 3D chemistry climate model, fed by aerosol size distributions from a zonal mean aerosol model, to simulate continuous injection of 1-10 Mt/a into the lower tropical stratosphere. In contrast to the case for all previous work, the particles are predicted to grow to larger sizes than are observed after volcanic eruptions. The reason is the continuous supply of sulfuric acid and hence freshly formed small aerosol particles, which enhance the formation of large aerosol particles by coagulation and, to a lesser extent, by condensation. Owing to their large size, these particles have a reduced albedo. Furthermore, their sedimentation results in a non-linear relationship between stratospheric aerosol burden and annual injection, leading to a reduction of the targeted cooling. More importantly, the sedimenting particles heat the tropical cold point tropopause and, hence, the stratospheric entry mixing ratio of H{sub 2}O increases. Therefore, geoengineering by means of sulfate aerosols is predicted to accelerate the hydroxyl catalyzed ozone destruction cycles and cause a significant depletion of the ozone layer even though future halogen concentrations will be significantly reduced.

  5. Generation of aerosolized drugs.

    Science.gov (United States)

    Wolff, R K; Niven, R W

    1994-01-01

    The expanding use of inhalation therapy has placed demands on current aerosol generation systems that are difficult to meet with current inhalers. The desire to deliver novel drug entities such as proteins and peptides, as well as complex formulations including liposomes and microspheres, requires delivery systems of improved efficiency that will target the lung in a reproducible manner. These efforts have also been spurred by the phase out of chlorofluorocarbons (CFCs) and this has included a directed search for alternative propellants. Consequently, a variety of new aerosol devices and methods of generating aerosols are being studied. This includes the use of freon replacement propellants, dry powder generation systems, aqueous unit spray systems and microprocessor controlled technologies. Each approach has advantages and disadvantages depending upon each principle of action and set of design variables. In addition, specific drugs may be better suited for one type of inhaler device vs. another. The extent to which aerosol generation systems achieve their goals is discussed together with a summary of selected papers presented at the recent International Congress of Aerosols in Medicine.

  6. Microphysical and chemical characteristics of near-water aerosol over White and Kara Seas

    Science.gov (United States)

    Terpugova, S. A.; Polkin, V. V.; Panchenko, M. V.; Golobokova, L. P.; Kozlov, V. S.; Shmargunov, V. P.; Shevchenko, V. P.; Lisitzin, A. P.

    2009-04-01

    The results are presented of five-year-long (2003-2007) study of the spatial - temporal variability of the near-water aerosol in the water area of White and Kara Seas (55, 64, 71 and 80-th cruises of RV "Professor Shtockman"; 53 and 54-th cruises of RV "Akademik Mstislav Keldysh"). Measurements of aerosol microphysical characteristics were carried out by means of the automated mobile aerosol complex consisting of nephelometer, photoelectric counter and aethalometer. The aerosol disperse composition was studied with photoelectric counter in 256 size intervals from 0.4 to 10 m. About 1500 series of measurements were carried out in White Sea, and about 1400 series in Kara Sea. Chemical characteristics of aerosol were determined from samples collected on aerosol filters (92 samples were collected in White Sea and 48 in Kara Sea). The ion composition was determined under laboratory conditions. The H+, Na+, K+, Ca2+, Mg2+, NH4+, Cl-, NO3-, HCO3-, SO42- ions were under examination. Comparing aerosol characteristics of two seas, one can note that the mean values of the aerosol content parameters in Kara Sea are less than in White Sea. The ratio of the aerosol mass concentration are from 2 (Yamal Peninsula, northern part of Novaya Zemlya) to 9 times (Blagopoluchia Bay, Ob' Gulf). The differences in the concentration of black carbon vary from 3 (Yamal Peninsula) to 17 times (Blagopoluchia Bay). The differences in the aerosol number concentration NA are not so big. The values NA near Kara Gate, Yamal Peninsula and northern part of Novaya Zemlya are practically the same as in White Sea. The concentration NA at Ob' gulf is one order of magnitude less than in White sea. The obtained aerosol volume size distributions were approximated by the sums of two fractions, submicron and coarse, with lognormal size distributions. The mean volume size distribution of submicron fraction in White Sea is approximated by the distribution with the variance of the radius logarithm s=0.6 and modal

  7. Variability of Biomass Burning Aerosols Layers and Near Ground

    Science.gov (United States)

    Vasilescu, Jeni; Belegante, Livio; Marmureanu, Luminita; Toanca, Flori

    2016-06-01

    The aim of this study is to characterize aerosols from both chemical and optical point of view and to explore the conditions to sense the same particles in elevated layers and at the ground. Three days of continuous measurements using a multi-wavelength depolarization lidar(RALI) and a C-ToF-AMS aerosol mass spectrometer are analyzed. The presence of smoke particles was assessed in low level layers from RALI measurements. Chemical composition of submicronic volatile/semi-volatile aerosols at ground level was monitored by the CTOF AMS Several episodes of biomass burning aerosols have been identified by both techniques due to the presence of specific markers (f60, linear particle depolarization ratio, Ängström exponent).

  8. Chemical aerosol Raman detector

    Science.gov (United States)

    Aggarwal, R. L.; Farrar, L. W.; Di Cecca, S.; Amin, M.; Perkins, B. G.; Clark, M. L.; Jeys, T. H.; Sickenberger, D. W.; D'Amico, F. M.; Emmons, E. D.; Christesen, S. D.; Kreis, R. J.; Kilper, G. K.

    2017-03-01

    A sensitive chemical aerosol Raman detector (CARD) has been developed for the trace detection and identification of chemical particles in the ambient atmosphere. CARD includes an improved aerosol concentrator with a concentration factor of about 40 and a CCD camera for improved detection sensitivity. Aerosolized isovanillin, which is relatively safe, has been used to characterize the performance of the CARD. The limit of detection (SNR = 10) for isovanillin in 15 s has been determined to be 1.6 pg/cm3, which corresponds to 6.3 × 109 molecules/cm3 or 0.26 ppb. While less sensitive, CARD can also detect gases. This paper provides a more detailed description of the CARD hardware and detection algorithm than has previously been published.

  9. Sparse aerosol models beyond the quadrature method of moments

    Science.gov (United States)

    McGraw, Robert

    2013-05-01

    This study examines a class of sparse aerosol models derived from linear programming (LP). The widely used quadrature method of moments (QMOM) is shown to fall into this class. Here it is shown how other sparse aerosol models can be constructed, which are not based on moments of the particle size distribution. The new methods enable one to bound atmospheric aerosol physical and optical properties using arbitrary combinations of model parameters and measurements. Rigorous upper and lower bounds, e.g. on the number of aerosol particles that can activate to form cloud droplets, can be obtained this way from measurement constraints that may include total particle number concentration and size distribution moments. The new LP-based methods allow a much wider range of aerosol properties, such as light backscatter or extinction coefficient, which are not easily connected to particle size moments, to also be assimilated into a list of constraints. Finally, it is shown that many of these more general aerosol properties can be tracked directly in an aerosol dynamics simulation, using SAMs, in much the same way that moments are tracked directly in the QMOM.

  10. Comparison of near surface and column-integrated atmospheric aerosol optical properties

    Science.gov (United States)

    Aryal, Rudra Prasad

    Optical and chemical properties of size-resolved aerosols in near-surface air at Tudor Hill, Bermuda were measured between July 2006 and June 2009. Vertical distributions of aerosol backscattering and column-averaged aerosol optical properties were characterized with a Micro-pulse lidar (MPL) and a CIMEL automated sun-sky radiometer. The chemical species in size-segregated aerosols in marine air were compared with the surface level aerosol optical properties. The aerosol concentration, along with chemical components, was compared with the surface level wind speed and showed a significant correlation with the sea salt components. The non-sea salt components such as non-sea salt sulfate and ammonium did not show a correlation with the surface level wind speed. A comparison between scattering data at surface level with the extinction coefficient at the lowest altitude bin (75m) from the lidar inversion shows a consistent correlation but is quantitatively different. This quantitative discrepancy was explained based on the hygroscopic growth due to differences in relative humidity in measurement conditions. Aerosol optical properties measured near the surface were often significantly correlated with those averaged over the column. These include scattering by near-surface bulk aerosol at 530 nm versus column aerosol optical depth (AOD), near-surface sub-microm scattering fraction versus column averaged sub-microm scattering fraction, and the average angstrom exponent over column and lidar ratio derived using column integrated size distribution and complex refractive index. We also found that the single scattering albedo (ω o) measured at the surface by combining daily averages of the aerosol absorption and aerosol light scattering were in the same range as the instantaneous ω o retrieved for the column. The relative contribution of submicron aerosol light scattering to total aerosol light scattering is slightly higher in the column relative to the surface. Surface

  11. Use of the CALIOP vertical feature mask for evaluating global aerosol models

    Directory of Open Access Journals (Sweden)

    E. P. Nowottnick

    2015-01-01

    Full Text Available Global aerosol distributions provided by the NASA Modern Era Retrospective Analysis for Research and Applications aerosol reanalysis (MERRAero are evaluated using the aerosol types identified by the CALIOP vertical feature mask (VFM algorithm, focusing especially on Saharan dust distributions during July 2009. MERRAero is comprised of an aerosol simulation produced in the Goddard Earth Observing System version 5 (GEOS-5 Earth system model and incorporates assimilation of MODIS-derived aerosol optical thickness to constrain column aerosol loadings. For comparison to the CALIOP VFM we construct two synthetic VFMs using the MERRAero aerosol distributions: a Level 2 VFM in which simulated MERRAero total attenuated backscatter and estimated particulate depolarization ratios are input directly to the CALIOP VFM typing algorithm, and a Level 3 VFM in which we map the aerosol species in MERRAero to the CALIOP VFM types. By comparing the simulated MERRAero-Level 2 VFM to CALIOP VFM we can diagnose the aerosol transport and speciation in MERRAero. By comparing the MERRAero-Level 2 and MERRAero-Level 3 simulated VFMs we perform a simple Observing System Simulation Experiment (OSSE, which is useful for identifying shortcomings in the CALIOP VFM algorithm itself. We find that despite having our column AOT constrained by MODIS, comparison to the CALIOP VFM reveals a greater occurrence of dusty aerosol layers in our MERRAero-Level 2 VFM, due to errors in MERRAero aerosol speciation. Additionally, we find that the CALIOP VFM algorithm classification for desert dust and polluted dust should be reconsidered for aerosol features that contain dust mixtures in low aerosol loadings, as our application of the CALIOP VFM to MERRAero distributions flagged a greater presence of dusty vs. marine aerosols when our two MERRAero VFMs were compared.

  12. Influences of in-cloud aerosol scavenging parameterizations on aerosol concentrations and wet deposition in ECHAM5-HAM

    Directory of Open Access Journals (Sweden)

    B. Croft

    2010-02-01

    Full Text Available A diagnostic cloud nucleation scavenging scheme, which determines stratiform cloud scavenging ratios for both aerosol mass and number distributions, based on cloud droplet, and ice crystal number concentrations, is introduced into the ECHAM5-HAM global climate model. This scheme is coupled with a size-dependent in-cloud impaction scavenging parameterization for both cloud droplet-aerosol, and ice crystal-aerosol collisions. The aerosol mass scavenged in stratiform clouds is found to be primarily (>90% scavenged by cloud nucleation processes for all aerosol species, except for dust (50%. The aerosol number scavenged is primarily (>90% attributed to impaction. 99% of this impaction scavenging occurs in clouds with temperatures less than 273 K. Sensitivity studies are presented, which compare aerosol concentrations, burdens, and deposition for a variety of in-cloud scavenging approaches: prescribed fractions, a more computationally expensive prognostic aerosol cloud processing treatment, and the new diagnostic scheme, also with modified assumptions about in-cloud impaction and nucleation scavenging. Our results show that while uncertainties in the representation of in-cloud scavenging processes can lead to differences in the range of 20–30% for the predicted annual, global mean aerosol mass burdens, and near to 50% for accumulation mode aerosol number burden, the differences in predicted aerosol mass concentrations can be up to one order of magnitude, particularly for regions of the middle troposphere with temperatures below 273 K where mixed and ice phase clouds exist. Different parameterizations for impaction scavenging changed the predicted global, annual mean number removal attributed to ice clouds by seven-fold, and the global, annual dust mass removal attributed to impaction by two orders of magnitude. Closer agreement with observations of black carbon profiles from aircraft (increases near to one order of magnitude for mixed phase clouds

  13. Sensitivity of Remote Aerosol Distributions to Representation of Cloud-Aerosol Interactions in a Global Climate Model

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hailong; Easter, Richard C.; Rasch, Philip J.; Wang, Minghuai; Liu, Xiaohong; Ghan, Steven J.; Qian, Yun; Yoon, Jin-Ho; Ma, Po-Lun; Vinoj, V.

    2013-06-05

    Many global aerosol and climate models, including the widely used Community Atmosphere Model version 5 (CAM5), have large biases in predicting aerosols in remote regions such as upper troposphere and high latitudes. In this study, we conduct CAM5 sensitivity simulations to understand the role of key processes associated with aerosol transformation and wet removal affecting the vertical and horizontal long-range transport of aerosols to the remote regions. Improvements are made to processes that are currently not well represented in CAM5, which are guided by surface and aircraft measurements together with results from a multi-scale aerosol-climate model (PNNL-MMF) that explicitly represents convection and aerosol-cloud interactions at cloud-resolving scales. We pay particular attention to black carbon (BC) due to its importance in the Earth system and the availability of measurements. We introduce into CAM5 a new unified scheme for convective transport and aerosol wet removal with explicit aerosol activation above convective cloud base. This new implementation reduces the excessive BC aloft to better simulate observed BC profiles that show decreasing mixing ratios in the mid- to upper-troposphere. After implementing this new unified convective scheme, we examine wet removal of submicron aerosols that occurs primarily through cloud processes. The wet removal depends strongly on the sub-grid scale liquid cloud fraction and the rate of conversion of liquid water to precipitation. These processes lead to very strong wet removal of BC and other aerosols over mid- to high latitudes during winter months. With our improvements, the Arctic BC burden has a10-fold (5-fold) increase in the winter (summer) months, resulting in a much better simulation of the BC seasonal cycle as well. Arctic sulphate and other aerosol species also increase but to a lesser extent. An explicit treatment of BC aging with slower aging assumptions produces an additional 30-fold (5-fold) increase in

  14. Aerosol processing in stratiform clouds in ECHAM6-HAM

    Science.gov (United States)

    Neubauer, David; Lohmann, Ulrike; Hoose, Corinna

    2013-04-01

    chemical components as well as 5 tracers for aerosol particles in ice crystals. This allows simulations of aerosol processing in warm, mixed-phase (e.g. through the Bergeron-Findeisen process) and ice clouds. The fixed scavenging ratios used for wet deposition in clouds in standard HAM are replaced by an explicit treatment of collision of cloud droplets/ice crystals with interstitial aerosol particles. Nucleation scavenging of aerosol particles by acting as cloud condensation nuclei or ice nuclei, freezing and evaporation of cloud droplets and melting and sublimation of ice crystals are treated explicitly. In extension to previous studies, aerosol particles from evaporating precipitation are released to modes which correspond to their size. Cloud processing of aerosol particles changes their size distribution and hence influences cloud droplet and ice crystal number concentrations as well as precipitation rate, which in turn affects aerosol concentrations. Results will be presented at the conference. Hoose et al., JGR, 2008a, doi: 10.1029/2007JD009251 Hoose et al., ACP, 2008b, doi: 10.5194/acp-8-6939-2008 Stevens et al., 2013, submitted Stier et al., ACP, 2005, doi: 10.5194/acp-5-1125-2005

  15. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORES 9 & 10: COLUMNAR HEXAGONAL POINT-ON-POINT PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess

    2014-03-01

    PROTEUS is a zero-power research reactor based on a cylindrical graphite annulus with a central cylindrical cavity. The graphite annulus remains basically the same for all experimental programs, but the contents of the central cavity are changed according to the type of reactor being investigated. Through most of its service history, PROTEUS has represented light-water reactors, but from 1992 to 1996 PROTEUS was configured as a pebble-bed reactor (PBR) critical facility and designated as HTR-PROTEUS. The nomenclature was used to indicate that this series consisted of High Temperature Reactor experiments performed in the PROTEUS assembly. During this period, seventeen critical configurations were assembled and various reactor physics experiments were conducted. These experiments included measurements of criticality, differential and integral control rod and safety rod worths, kinetics, reaction rates, water ingress effects, and small sample reactivity effects (Ref. 3). HTR-PROTEUS was constructed, and the experimental program was conducted, for the purpose of providing experimental benchmark data for assessment of reactor physics computer codes. Considerable effort was devoted to benchmark calculations as a part of the HTR-PROTEUS program. References 1 and 2 provide detailed data for use in constructing models for codes to be assessed. Reference 3 is a comprehensive summary of the HTR-PROTEUS experiments and the associated benchmark program. This document draws freely from these references. Only Cores 9 and 10 are evaluated in this benchmark report due to similarities in their construction. The other core configurations of the HTR-PROTEUS program are evaluated in their respective reports as outlined in Section 1.0. Cores 9 and 10 were evaluated and determined to be acceptable benchmark experiments.

  16. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORES 9 & 10: COLUMNAR HEXAGONAL POINT-ON-POINT PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess

    2013-03-01

    PROTEUS is a zero-power research reactor based on a cylindrical graphite annulus with a central cylindrical cavity. The graphite annulus remains basically the same for all experimental programs, but the contents of the central cavity are changed according to the type of reactor being investigated. Through most of its service history, PROTEUS has represented light-water reactors, but from 1992 to 1996 PROTEUS was configured as a pebble-bed reactor (PBR) critical facility and designated as HTR-PROTEUS. The nomenclature was used to indicate that this series consisted of High Temperature Reactor experiments performed in the PROTEUS assembly. During this period, seventeen critical configurations were assembled and various reactor physics experiments were conducted. These experiments included measurements of criticality, differential and integral control rod and safety rod worths, kinetics, reaction rates, water ingress effects, and small sample reactivity effects (Ref. 3). HTR-PROTEUS was constructed, and the experimental program was conducted, for the purpose of providing experimental benchmark data for assessment of reactor physics computer codes. Considerable effort was devoted to benchmark calculations as a part of the HTR-PROTEUS program. References 1 and 2 provide detailed data for use in constructing models for codes to be assessed. Reference 3 is a comprehensive summary of the HTR-PROTEUS experiments and the associated benchmark program. This document draws freely from these references. Only Cores 9 and 10 are evaluated in this benchmark report due to similarities in their construction. The other core configurations of the HTR-PROTEUS program are evaluated in their respective reports as outlined in Section 1.0. Cores 9 and 10 were evaluated and determined to be acceptable benchmark experiments.

  17. Sulfur aerosol in the clouds of Venus

    Science.gov (United States)

    Krasnopolsky, Vladimir A.

    2016-08-01

    The photochemical model for the middle atmosphere of Venus (Krasnopolsky, V.A. [2012] Icarus, 218, 230-246) predicts sulfur aerosol as a product of the OCS photolysis at 55-60 km. The calculated mass loading is much smaller than that of the mode 1 particles in the upper cloud layer. The chemical kinetic model for the lower atmosphere (Krasnopolsky, V.A. [2013], Icarus, 225, 570-580) results in a constant mixing ratio of 20 ppm for OCS + XSX. This means the S8 mixing ratio of 2.5 ppm near the model upper boundary at 47 km. Using this abundance, the calculated profile of the sulfur aerosol has a bottom that coincides with the lower boundary of modes 2 and 3 and constitutes ∼10% of the total mass loading in the lower cloud layer. Sulfur aerosol cannot be the near UV absorber because its abundance is too low at the cloud tops and disagrees with the profile of the absorber observed by Venera 14.

  18. Comparison of UV-RSS spectral measurements and TUV model runs for clear skies for the May 2003 ARM aerosol intensive observation period

    Directory of Open Access Journals (Sweden)

    P. W. Kiedron

    2008-03-01

    Full Text Available The first successful deployment of the fully-operational ultraviolet rotating shadow-band spectroradiometer occurred during the May 2003 US Department of Energy's Atmospheric Radiation Measurement program's Aerosol Intensive Observation Period. The aerosol properties in the visible range were characterized using redundant measurements with several instruments to determine the column aerosol optical depth, the single scattering albedo, and the asymmetry parameter needed as input for radiative transfer calculations of the downwelling direct normal and diffuse horizontal solar irradiance in clear-sky conditions. The Tropospheric Ultraviolet and Visible (TUV radiative transfer model developed by Madronich and his colleagues at the US National Center for Atmospheric Research was used for the calculations of the spectral irradiance between 300–360 nm. Since there are few ultraviolet measurements of aerosol properties, most of the input aerosol data for the radiative transfer model are based on the assumption that UV input parameters can be extrapolated from the visible portion of the spectrum. Disagreements among available extraterrestrial spectra, which are discussed briefly, suggested that instead of comparing irradiances, measured and modeled spectral transmittances between 300–360 nm should be compared for the seven cases studied. Transmittance was calculated by taking the ratios of the measured irradiances to the Langley-derived, top-of-the-atmosphere irradiances. The cases studied included low to moderate aerosol loads and low to high solar-zenith angles. A procedure for retrieving single scattering albedo in the ultraviolet based on the comparisons of direct and diffuse transmittance is outlined.

  19. Physico-chemical characterization of secondary organic aerosol derived from catechol and guaiacol as a model substance for atmospheric humic-like substances

    Directory of Open Access Journals (Sweden)

    J. Ofner

    2010-07-01

    Full Text Available Secondary organic aerosol was produced from the aromatic precursors catechol and guaiacol by reaction with ozone in the presence and absence of simulated sunlight and humidity and investigated for its properties as a proxy for humic-like substances (HULIS. Beside a small particle size, a relatively low molecular weight and typical optical features in the UV/VIS spectral range, HULIS contain a typical aromatic and/or olefinic chemical structure and highly oxidized functional groups within a high chemical diversity. Various methods were used to characterize the secondary organic aerosols obtained: Fourier transform infrared spectroscopy (FTIR demonstrated the formation of different carbonyl containing functional groups as well as structural and functional differences between aerosols formed at different environmental conditions. UV/VIS spectroscopy of filter samples showed that the particulate matter absorbs far into the visible range up to more than 500 nm. Ultrahigh resolved mass spectroscopy (ICR-FT/MS determined O/C-ratios between 0.3 and 1 and main molecular weights between 200 and 500 Da. Temperature-programmed-pyrolysis mass spectroscopy identified carboxylic acids and lactones as major functional groups. Particle sizing using CNC-DMPS demonstrated the formation of small particles during a secondary organic aerosol formation process. Particle imaging using field-emission-gun scanning electron microscopy (FEG-SEM showed spherical particles, forming clusters and chains. Hence, secondary organic aerosols from catechol and guaiacol are appropriate model substances for studies of the processing of aromatic secondary organic aerosols and atmospheric HULIS on the laboratory scale.

  20. Free Tropospheric Aerosols Over South Africa

    Science.gov (United States)

    Elina, Giannakaki; Pfüller, Anne; Korhonen, Kimmo; Mielonen, Tero; Laakso, Lauri; Vakkari, Ville; Baars, Holger; Engelmann, Ronny; Beukes, Johan P.; Van Zyl, Pieter G.; Josipovic, Miroslav; Tiitta, Petri; Chiloane, Kgaugelo; Piketh, Stuart; Lihavainen, Heikki; Lehtinen, Kari

    2016-06-01

    Raman lidar data of one year was been analyzed to obtain information relating aerosol layers in the free troposphere over South Africa, Elandsfontein. In total, 375 layers were observed above the boundary layer during the period 30th January 2010 - 31st January 2011. The seasonal behavior of aerosol layer geometrical characteristics as well as intensive and extensive optical properties were studied. In general, layers were observed at higher altitudes during spring (2520 ± 970 m) while the geometrical layer depth did not show any significant seasonal dependence. The variations of most of the intensive and extensive optical properties analyzed were high during all seasons. Layers were observed at mean altitude of 2100 m ± 1000 m with lidar ratio at 355 nm of 67 ± 25 and extinction-related Ångström exponent between 355 and 532 nm of 1.9 ± 0.8.

  1. Free Tropospheric Aerosols Over South Africa

    Directory of Open Access Journals (Sweden)

    Elina Giannakaki

    2016-01-01

    Full Text Available Raman lidar data of one year was been analyzed to obtain information relating aerosol layers in the free troposphere over South Africa, Elandsfontein. In total, 375 layers were observed above the boundary layer during the period 30th January 2010 – 31st January 2011. The seasonal behavior of aerosol layer geometrical characteristics as well as intensive and extensive optical properties were studied. In general, layers were observed at higher altitudes during spring (2520 ± 970 m while the geometrical layer depth did not show any significant seasonal dependence. The variations of most of the intensive and extensive optical properties analyzed were high during all seasons. Layers were observed at mean altitude of 2100 m ± 1000 m with lidar ratio at 355 nm of 67 ± 25 and extinction-related Ångström exponent between 355 and 532 nm of 1.9 ± 0.8.

  2. Variation in daytime troposphereic aerosol via LIDAR and sunphotometer measurements in Penang, Malaysia

    Science.gov (United States)

    Tan, F. Y.; Hee, W. S.; Hwee, S. L.; Abdullah, K.; Tiem, L. Y.; Matjafri, M. Z.; Lolli, S.; Holben, B.; Welton, E. J.

    2014-03-01

    Aerosol is one of the important factors that will influence the air quality, visibility, clouds, and precipitation processes in the troposphere. In this work, we investigated the variation of aerosol during daytime in Penang, Malaysia in certain days within July 2013. Vertical LIDAR scattering ratio and backscattering profiles, and columnar optical properties (optical depth, Angström exponent) of aerosols were measured using Raymetrics LIDAR and a CIMEL sunphotometer respectively. Specifically, we have determined the daytime variation of intensity and distribution level of aerosol, as well as the planetary boundary layer (PBL) and cloud classification. Subsequently, the data of columnar aerosol optical depth (AOD) and size distribution in the atmospheric were used to quantify the properties of aerosol variation during daytime over Penang, Malaysia.

  3. Aerosols, light, and water: Measurements of aerosol optical properties at different relative humidities

    Science.gov (United States)

    Orozco, Daniel

    The Earth's atmosphere is composed of a large number of different gases as well as tiny suspended particles, both in solid and liquid state. These tiny particles, called atmospheric aerosols, have an immense impact on our health and on our global climate. Atmospheric aerosols influence the Earth's radiation budget both directly and indirectly. In the direct effect, aerosols scatter and absorb sunlight changing the radiative balance of the Earth-atmosphere system. Aerosols indirectly influence the Earth's radiation budget by modifying the microphysical and radiative properties of clouds as well as their water content and lifetime. In ambient conditions, aerosol particles experience hygroscopic growth due to the influence of relative humidity (RH), scattering more light than when the particles are dry. The quantitative knowledge of the RH effect and its influence on the light scattering coefficient and, in particular, on the phase function and polarization of aerosol particles is of substantial importance when comparing ground based observations with other optical aerosol measurements techniques such satellite and sunphotometric retrievals of aerosol optical depth and their inversions. This dissertation presents the aerosol hygroscopicity experiment investigated using a novel dryer-humidifier system, coupled to a TSI-3563 nephelometer, to obtain the light scattering coefficient (sp) as a function of relative humidity (RH) in hydration and dehydration modes. The measurements were performed in Porterville, CA (Jan 10-Feb 6, 2013), Baltimore, MD (Jul 3-30, 2013), and Golden, CO (Jul 12-Aug 10, 2014). Observations in Porterville and Golden were part of the NASA-sponsored DISCOVER-AQ project. The measured sp under varying RH in the three sites was combined with ground aerosol extinction, PM2:5mass concentrations, particle composition measurements, and compared with airborne observations performed during campaigns. The enhancement factor, f(RH), defined as the ratio of sp

  4. Aerosol Composition, Size Distribution and Optical Properties during SEAC4RS Simulated by a Sectional Aerosol Model

    Science.gov (United States)

    Yu, P.; Toon, O. B.; Bardeen, C.; Wiedinmyer, C.; Jimenez, J. L.; Campuzano Jost, P.; Froyd, K. D.; Ziemba, L. D.; Schwarz, J. P.; Perring, A. E.; Wagner, N.; Neely, R. R., III

    2014-12-01

    Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field mission in August and September 2013 provided large aerosol/gas datasets over the Southeastern U.S. We use a sectional microphysics model (CARMA) coupled with CAM-Chem to study the aerosol composition, size distribution, vertical distribution and optical properties during the SEAC4RS campaign. Our simulations are within the observational error bars for the mass of organics, sulfate and black carbon from the boundary layer to upper-troposphere. CARMA, as a sectional model, provides detailed aerosol size distributions from nano-meters to tens of microns, which is important to determine optical properties. We investigate how the aerosol size distribution varies with altitude. Modeled spatial gradients of [O]:[C] and [OC]:[SO4-2] ratios are compared with the AMS and PALMS data collected over forests, fires and cities. These ratios are important to constrain the budget of secondary organic aerosols. We will discuss the values of these ratios over the U.S. and the rest of the world.

  5. Spatial Variability of AERONET Aerosol Optical Properties and Satellite Data in South Korea during NASA DRAGON-Asia Campaign.

    Science.gov (United States)

    Lee, Hyung Joo; Son, Youn-Suk

    2016-04-05

    We investigated spatial variability in aerosol optical properties, including aerosol optical depth (AOD), fine-mode fraction (FMF), and single scattering albedo (SSA), observed at 21 Aerosol Robotic Network (AERONET) sites and satellite remote sensing data in South Korea during the spring of 2012. These dense AERONET networks established in a National Aeronautics and Space Administration (NASA) field campaign enabled us to examine the spatially detailed aerosol size distribution and composition as well as aerosol levels. The springtime particle air quality was characterized by high background aerosol levels and high contributions of coarse-mode aerosols to total aerosols. We found that between-site correlations and coefficient of divergence for AOD and FMF strongly relied on the distance between sites, particularly in the south-north direction. Higher AOD was related to higher population density and lower distance from highways, and the aerosol size distribution and composition reflected source-specific characteristics. The ratios of satellite NO2 to AOD, which indicate the relative contributions of local combustion sources to aerosol levels, represented higher local contributions in metropolitan Seoul and Pusan. Our study demonstrates that the aerosol levels were determined by both local and regional pollution and that the relative contributions of these pollutions to aerosols generated spatial heterogeneity in the particle air quality.

  6. Enhanced UV Absorption in Carbonaceous Aerosols during MILAGRO and Identification of Potential Organic Contributors.

    Science.gov (United States)

    Mangu, A.; Kelley, K. L.; Marchany-Rivera, A.; Kilaparty, S.; Gunawan, G.; Gaffney, J. S.; Marley, N. A.

    2007-12-01

    Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) during the month of March, 2006 by using a 7- channel aethalometer (Thermo-Anderson). These measurements, obtained at 370, 470, 520, 590, 660, 880, and 950 nm at a 5 minute time resolution, showed an enhanced absorption in the UV over that expected from carbon soot alone. Samples of fine atmospheric aerosols (less than 0.1micron) were also collected at site T0 and T1 (Universidad Technologica de Tecamac, State of Mexico) from 5 am to 5 pm (day) and from 5 pm to 5 am (night) during the month of March 2006. The samples were collected on quartz fiber filters with high volume impactor samplers. The samples have been characterized for total carbon content (stable isotope ratio mass spectroscopy) and natural radionuclide tracers (210Pb, 210Po, 210Bi, 7Be, 13C, 14C, 40K, 15N). Continuous absorption spectra of these aerosol samples have been obtained in the laboratory from 280 to 900nm with the use of an integrating sphere coupled to a UV-visible spectrometer (Beckman DU with a Labsphere accessory). The integrating sphere allows the detector to collect and spatially integrate the total radiant flux reflected from the sample and therefore allows for the measurement of absorption on highly reflective or diffusely scattering samples (1). The continuous spectra also show an enhanced UV absorption over that expected from carbon soot and the general profiles are quite similar to those observed for humic and fulvic acids found as colloidal materials in surface and groundwaters (2), indicating the presence of humic-like substances (HULIS) in the fine aerosols. The spectra also show evidence of narrow band absorbers below 400 nm typical of polycyclic aromatics (PAH) and nitrated aromatic compounds. Spectra were also obtained on NIST standard diesel soot (SRM 2975), NIST standard air particulate matter (SRM 8785

  7. Aerosol pollution potential from major population centers

    Directory of Open Access Journals (Sweden)

    D. Kunkel

    2013-04-01

    deposition fields to estimate regions with high deposition, that is more than 1% or more than 5% of the corresponding tracer emission deposited in this region. In doing so, we find that the high deposition areas are larger for aerosols with diameters of 10.0 μm, and these differ less between the MPCs than for aerosols with diameters smaller than 2.5 μm due to faster deposition. Furthermore, cities in regions with high precipitation rates or unfavorable geographic locations, e.g., in a basin, suffer most of this high deposition. Most of the high deposition occurs over land, although about 50% of the MPCs are located along coastlines. By folding the aerosol deposition fields with geographical distributions of cropland, pasture, and forest, the impact on different land ecosystems is assessed. In general, forest is exposed most to deposition from MPCs while pastureland is least affected. Moreover, the impact on humans, measured with a threshold exceedance of pollutant surface mixing ratios, is more dependent on population densities than on the size of the area with a certain mixing ratio.

  8. Aerosol pollution potential from major population centers

    Directory of Open Access Journals (Sweden)

    D. Kunkel

    2012-09-01

    aerosol deposition fields to estimate regions with high deposition, that is more than 1% or more than 5% of the corresponding tracer emission deposited in this region. In doing so, we find that the high deposition areas are larger for larger aerosols, and these differ less between the MPCs than for smaller aerosols due to faster deposition. Furthermore, cities in regions with high precipitation rates or unfavorable geographic location, e.g. in a basin, suffer most of this high deposition. Most of the high deposition occurs over land, although about 50% of the MPCs are located along coastlines. By folding the aerosol deposition fields with geographical distributions of cropland, pasture, and forest, the impact on different land ecosystems is assessed. In general, forest are exhibited most to deposition from MPCs while pasture land is least affected. Moreover, the impact on humans, measured with a threshold exceedance of pollutant surface mixing ratios, is more dependent on population densities than on the size of the area holding a certain mixing ratio.

  9. Laboratory Experiments and Instrument Intercomparison Studies of Carbonaceous Aerosol Particles

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-20

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

  10. Sensitivity of remote aerosol distributions to representation of cloud–aerosol interactions in a global climate model

    Directory of Open Access Journals (Sweden)

    H. Wang

    2013-06-01

    Full Text Available Many global aerosol and climate models, including the widely used Community Atmosphere Model version 5 (CAM5, have large biases in predicting aerosols in remote regions such as the upper troposphere and high latitudes. In this study, we conduct CAM5 sensitivity simulations to understand the role of key processes associated with aerosol transformation and wet removal affecting the vertical and horizontal long-range transport of aerosols to the remote regions. Improvements are made to processes that are currently not well represented in CAM5, which are guided by surface and aircraft measurements together with results from a multi-scale aerosol–climate model that explicitly represents convection and aerosol–cloud interactions at cloud-resolving scales. We pay particular attention to black carbon (BC due to its importance in the Earth system and the availability of measurements. We introduce into CAM5 a new unified scheme for convective transport and aerosol wet removal with explicit aerosol activation above convective cloud base. This new implementation reduces the excessive BC aloft to better simulate observed BC profiles that show decreasing mixing ratios in the mid- to upper-troposphere. After implementing this new unified convective scheme, we examine wet removal of submicron aerosols that occurs primarily through cloud processes. The wet removal depends strongly on the subgrid-scale liquid cloud fraction and the rate of conversion of liquid water to precipitation. These processes lead to very strong wet removal of BC and other aerosols over mid- to high latitudes during winter months. With our improvements, the Arctic BC burden has a 10-fold (5-fold increase in the winter (summer months, resulting in a much-better simulation of the BC seasonal cycle as well. Arctic sulphate and other aerosol species also increase but to a lesser extent. An explicit treatment of BC aging with slower aging assumptions produces an additional 30-fold (5-fold

  11. Aerosol classification from airborne HSRL and comparisons with the CALIPSO vertical feature mask

    Directory of Open Access Journals (Sweden)

    S. P. Burton

    2013-05-01

    Full Text Available Aerosol classification products from the NASA Langley Research Center (LaRC airborne High Spectral Resolution Lidar (HSRL-1 on the NASA B200 aircraft are compared with coincident V3.01 aerosol classification products from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP instrument on the CALIPSO satellite. For CALIOP, aerosol classification is a key input to the aerosol retrieval, and must be inferred using aerosol loading-dependent observations and location information. In contrast, HSRL-1 makes direct measurements of aerosol intensive properties, including the lidar ratio, that provide information on aerosol type. In this study, comparisons are made for 109 underflights of the CALIOP orbit track. We find that 62% of the CALIOP marine layers and 54% of the polluted continental layers agree with HSRL-1 classification results. In addition, 80% of the CALIOP desert dust layers are classified as either dust or dusty mix byHSRL-1. However, agreement is less for CALIOP smoke (13% and polluted dust (35% layers. Specific case studies are examined, giving insight into the performance of the CALIOP aerosol type algorithm. In particular, we find that the CALIOP polluted dust type is overused due to an attenuation-related depolarization bias. Furthermore, the polluted dust type frequently includes mixtures of dust plus marine aerosol. Finally, we find that CALIOP's identification of internal boundaries between different aerosol types in contact with each other frequently do not reflect the actual transitions between aerosol types accurately. Based on these findings, we give recommendations which may help to improve the CALIOP aerosol type algorithms.

  12. A numerical study of aerosol effects on electrification of thunderstorms

    Science.gov (United States)

    Tan, Y. B.; Shi, Z.; Chen, Z. L.; Peng, L.; Yang, Y.; Guo, X. F.; Chen, H. R.

    2017-02-01

    Numerical simulations are performed to investigate the effect of aerosol on microphysical and electrification in thunderstorm clouds. A two-dimensional (2-D) cumulus model with electrification scheme including non-inductive and inductive charge separation is used. The concentration of aerosol particles with distribution fitted by superimposing three log-normal distributions rises from 50 to 10,000 cm-3. The results show that the response of charge separation rate to the increase of aerosol concentration is nonmonotonic. When aerosol concentration is changed from 50 to 1000 cm-3, a stronger formation of cloud droplet, graupel and ice crystal results in increasing charge separation via non-inductive and inductive mechanism. However, in the range of 1000-3000 cm-3, vapor competition arises in the decrease of ice crystal mixing ratio and the reduction of ice crystals size leads to a slightly decrease in non-inductive charge rate, while inductive charging rate has no significant change in magnitude. Above aerosol concentration of 3000 cm-3, the magnitude of charging rate which keeps steady is insensitive to the increase in aerosol concentration. The results also suggest that non-inductive charge separation between ice crystal and graupel contributes to the main upper positive charge region and the middle negative charge region. Inductive graupel-cloud droplet charge separation, on the other hand, is found to play an important role in the development of lower charge region.

  13. Thermodynamic Characterization of Mexico City Aerosol during MILAGRO 2006

    Energy Technology Data Exchange (ETDEWEB)

    Fountoukis, C.; Nenes, A.; Sullivan, A.; Weber, R.; VanReken, T.; Fischer, M.; Matias, E.; Moya, M.; Farmer, D.; Cohen, R.C.

    2008-12-05

    Fast measurements of aerosol and gas-phase constituents coupled with the ISORROPIA-II thermodynamic equilibrium model are used to study the partitioning of semivolatile inorganic species and phase state of Mexico City aerosol sampled at the T1 site during the MILAGRO 2006 campaign. Overall, predicted semivolatile partitioning agrees well with measurements. PM{sub 2.5} is insensitive to changes in ammonia but is to acidic semivolatile species. For particle sizes up to 1 {micro}m diameter, semi-volatile partitioning requires 30-60 min to equilibrate; longer time is typically required during the night and early morning hours. When the aerosol sulfate-to-nitrate molar ratio is less than unity, predictions improve substantially if the aerosol is assumed to follow the deliquescent phase diagram. Treating crustal species as 'equivalent sodium' (rather than explicitly) in the thermodynamic equilibrium calculations introduces important biases in predicted aerosol water uptake, nitrate and ammonium; neglecting crustals further increases errors dramatically. This suggests that explicitly considering crustals in the thermodynamic calculations is required to accurately predict the partitioning and phase state of aerosols.

  14. The role of aerosols in cloud drop parameterizations and its applications in global climate models

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, C.C.; Penner, J.E. [Lawrence Livermore National Lab., CA (United States)

    1996-04-01

    The characteristics of the cloud drop size distribution near cloud base are initially determined by aerosols that serve as cloud condensation nuclei and the updraft velocity. We have developed parameterizations relating cloud drop number concentration to aerosol number and sulfate mass concentrations and used them in a coupled global aerosol/general circulation model (GCM) to estimate the indirect aerosol forcing. The global aerosol model made use of our detailed emissions inventories for the amount of particulate matter from biomass burning sources and from fossil fuel sources as well as emissions inventories of the gas-phase anthropogenic SO{sub 2}. This work is aimed at validating the coupled model with the Atmospheric Radiation Measurement (ARM) Program measurements and assessing the possible magnitude of the aerosol-induced cloud effects on climate.

  15. Developmental programming of polycystic ovary syndrome (PCOS): prenatal androgens establish pancreatic islet α/β cell ratio and subsequent insulin secretion

    Science.gov (United States)

    Ramaswamy, S.; Grace, C.; Mattei, A. A.; Siemienowicz, K.; Brownlee, W.; MacCallum, J.; McNeilly, A. S.; Duncan, W. C.; Rae, M. T.

    2016-01-01

    Exogenous androgenic steroids applied to pregnant sheep programmes a PCOS-like phenotype in female offspring. Via ultrasound guidance we applied steroids directly to ovine fetuses at d62 and d82 of gestation, and examined fetal (day 90 gestation) and postnatal (11 months old) pancreatic structure and function. Of three classes of steroid agonists applied (androgen - Testosterone propionate (TP), estrogen - Diethystilbesterol (DES) and glucocorticoid - Dexamethasone (DEX)), only androgens (TP) caused altered pancreatic development. Beta cell numbers were significantly elevated in prenatally androgenised female fetuses (P = 0.03) (to approximately the higher numbers found in male fetuses), whereas alpha cell counts were unaffected, precipitating decreased alpha:beta cell ratios in the developing fetal pancreas (P = 0.001), sustained into adolescence (P = 0.0004). In adolescence basal insulin secretion was significantly higher in female offspring from androgen-excess pregnancies (P = 0.045), and an exaggerated, hyperinsulinaemic response to glucose challenge (P = 0.0007) observed, whereas prenatal DES or DEX treatment had no effects upon insulin secretion. Postnatal insulin secretion correlated with beta cell numbers (P = 0.03). We conclude that the pancreas is a primary locus of androgenic stimulation during development, giving rise to postnatal offspring whose pancreas secreted excess insulin due to excess beta cells in the presence of a normal number of alpha cells. PMID:27265420

  16. Quantum Chemical Calculations Resolved Identification of Methylnitrocatechols in Atmospheric Aerosols.

    Science.gov (United States)

    Frka, Sanja; Šala, Martin; Kroflič, Ana; Huš, Matej; Čusak, Alen; Grgić, Irena

    2016-06-01

    Methylnitrocatechols (MNCs) are secondary organic aerosol (SOA) tracers and major contributors to atmospheric brown carbon; however, their formation and aging processes in atmospheric waters are unknown. To investigate the importance of aqueous-phase electrophilic substitution of 3-methylcatechol with nitronium ion (NO2(+)), we performed quantum calculations of their favorable pathways. The calculations predicted the formation of 3-methyl-5-nitrocatechol (3M5NC), 3-methyl-4-nitrocatechol (3M4NC), and a negligible amount of 3-methyl-6-nitrocatechol (3M6NC). MNCs in atmospheric PM2 samples were further inspected by LC/(-)ESI-MS/MS using commercial as well as de novo synthesized authentic standards. We detected 3M5NC and, for the first time, 3M4NC. In contrast to previous reports, 3M6NC was not observed. Agreement between calculated and observed 3M5NC/3M4NC ratios cannot unambiguously confirm the electrophilic mechanism as the exclusive formation pathway of MNCs in aerosol water. However, the examined nitration by NO2(+) is supported by (1) the absence of 3M6NC in the ambient aerosols analyzed and (2) the constant 3M5NC/3M4NC ratio in field aerosol samples, which indicates their common formation pathway. The magnitude of error one could make by incorrectly identifying 3M4NC as 3M6NC in ambient aerosols was also assessed, suggesting the importance of evaluating the literature regarding MNCs with special care.

  17. Levoglucosan and phenols in Antarctic marine, coastal and plateau aerosols.

    Science.gov (United States)

    Zangrando, Roberta; Barbaro, Elena; Vecchiato, Marco; Kehrwald, Natalie M; Barbante, Carlo; Gambaro, Andrea

    2016-02-15

    Due to its isolated location, Antarctica is a natural laboratory for studying atmospheric aerosols and pollution in remote areas. Here, we determined levoglucosan and phenolic compounds (PCs) at diverse Antarctic sites: on the plateau, a coastal station and during an oceanographic cruise. Levoglucosan and PCs reached the Antarctic plateau where they were observed in accumulation mode aerosols (with median levoglucosan concentrations of 6.4 pg m(-3) and 4.1 pg m(-3), and median PC concentrations of 15.0 pg m(-3) and 7.3 pg m(-3)). Aged aerosols arrived at the coastal site through katabatic circulation with the majority of the levoglucosan mass distributed on larger particulates (24.8 pg m(-3)), while PCs were present in fine particles (34.0 pg m(-3)). The low levoglucosan/PC ratios in Antarctic aerosols suggest that biomass burning aerosols only had regional, rather than local, sources. General acid/aldehyde ratios were lower at the coastal site than on the plateau. Levoglucosan and PCs determined during the oceanographic cruise were 37.6 pg m(-3) and 58.5 pg m(-3) respectively. Unlike levoglucosan, which can only be produced by biomass burning, PCs have both biomass burning and other sources. Our comparisons of these two types of compounds across a range of Antarctic marine, coastal, and plateau sites demonstrate that local marine sources dominate Antarctic PC concentrations.

  18. The global middle-atmosphere aerosol model MAECHAM5-SAM2: comparison with satellite and in-situ observations

    Directory of Open Access Journals (Sweden)

    R. Hommel

    2011-09-01

    Full Text Available In this paper we investigate results from a three-dimensional middle-atmosphere aerosol-climate model which has been developed to study the evolution of stratospheric aerosols. Here we focus on the stratospheric background period and evaluate several key quantities of the global distribution of stratospheric aerosols and their precursors with observations and other model studies. It is shown that the model fairly well reproduces in situ observations of the aerosol size and number concentrations in the upper troposphere and lower stratosphere (UT/LS. Compared to measurements from the limb-sounding SAGE II satellite instrument, modelled integrated aerosol quantities are more biased the lower the moment of the aerosol population is. Both findings are consistent with earlier work analysing the quality of SAGE II retrieved e.g. aerosol surface area densities in the volcanically unperturbed stratosphere (SPARC/ASAP, 2006; Thomason et al., 2008; Wurl et al., 2010.

    The model suggests that new particles are formed over large areas of the LS, albeit nucleation rates in the upper troposphere are at least one order of magnitude larger than those in the stratosphere. Hence, we suggest that both, tropospheric sulphate aerosols and particles formed in situ in the LS are maintaining the stability of the stratospheric aerosol layer in the absence of direct stratospheric emissions from volcanoes. Particle size distributions are clearly bimodal, except in the upper branches of the stratospheric aerosol layer where aerosols evaporate. Modelled concentrations of condensation nuclei (CN are smaller than measured in regions of the aerosol layer where aerosol mixing ratios are largest. This points to an overestimated particle growth by coagulation.

    Transport regimes of tropical stratospheric aerosol have been identified from modelled aerosol mixing ratios and correspond to those deduced from satellite extinction measurements. We found that convective

  19. Using the Aerosol Single Scattering Albedo and Angstrom Exponent from AERONET to Determine Aerosol Origins and Mixing States over the Indo-Gangetic Plain

    Science.gov (United States)

    Giles, D. M.; Holben, B. N.; Eck, T. F.; Sinyuk, A.; Slutsker, I.; Smirnov, A.; Schafer, J. S.; Dickerson, R. R.; Thompson, A. M.; Tripathi, S. N.; Singh, R. P.; Ghauri, B.

    2012-12-01

    .g., depolarization ratio or absorption Angstrom exponent) may provide improved definition of fine mode dominated aerosol types from U/I and BB sources [Burton et al., 2012, Giles et al., 2012]. Additional sites in India and Pakistan are also analyzed using available AERONET Version 2, Level 2.0 data.

  20. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    a relationship between plunging jet particle ux, oceanic particle ux, and energy dissipation rate in both systems. Previous sea spray aerosol studies dissipate an order of magnitude more energy for the same particle ux production as the open ocean. A scaling factor related to the energy expended in air...... emissions produced directly from bubble bursting as the result of air entrainment from breaking waves and particles generated from secondary emissions of volatile organic compounds. In the first paper, we study the chemical properties of particles produced from several sea water proxies with the use...... jet in high concentrations of surface active organics and brackish water salinities. The jet produces particles with less cloud condensation activity, implying an increase in organic material in aerosol particles produced by the plunging jet over the frit. In the second paper we determine...

  1. Aerosol Observing System (AOS) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Jefferson, A

    2011-01-17

    The Aerosol Observing System (AOS) is a suite of in situ surface measurements of aerosol optical and cloud-forming properties. The instruments measure aerosol properties that influence the earth’s radiative balance. The primary optical measurements are those of the aerosol scattering and absorption coefficients as a function of particle size and radiation wavelength and cloud condensation nuclei (CCN) measurements as a function of percent supersaturation. Additional measurements include those of the particle number concentration and scattering hygroscopic growth. Aerosol optical measurements are useful for calculating parameters used in radiative forcing calculations such as the aerosol single-scattering albedo, asymmetry parameter, mass scattering efficiency, and hygroscopic growth. CCN measurements are important in cloud microphysical models to predict droplet formation.

  2. Aerosol characterization during project POLINAT

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, D.E.; Hopkins, A.R.; Paladino, J.D.; Whitefield, P.D. [Missouri Univ., Rolla, MO (United States). Cloud and Aerosol Sciences Lab.; Lilenfeld, H.V. [McDonnell Douglas Aerospace-East, St. Louis, MO (United States)

    1997-12-31

    The objectives of the aerosol/particulate characterization measurements of project POLINAT (POLlution from aircraft emissions In the North ATlantic flight corridor) are: to search for aerosol/particulate signatures of air traffic emissions in the region of the North Atlantic Flight Corridor; to search for the aerosol/particulate component of large scale enhancement (`corridor effects`) of air traffic related species in the North Atlantic region; to determine the effective emission indices for the aerosol/particulate component of engine exhaust in both the near and far field of aircraft exhaust plumes; to measure the dispersion and transformation of the aerosol/particulate component of aircraft emissions as a function of ambient condition; to characterize background levels of aerosol/particulate concentrations in the North Atlantic Region; and to determine effective emission indices for engine exhaust particulates for regimes beyond the jet phase of plume expansion. (author) 10 refs.

  3. Acidic aerosol in urban air

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, M.; Yamaoka, S.; Miyazaki, T.; Oka, M.

    1982-01-01

    The distribution and chemical composition of acidic aerosol in Osaka City were investigated. Samples were collected at five sites in the city from June to September, 1979. Acidic aerosol was determined by the acid-base titration method, sulfate ion by barium chloride turbidimetry, nitrate ion by the xylenol method, and chloride ion by the mercury thiocyanate method. The concentration of acidic aerosol at five sites ranged from 7.7 micrograms per cubic meter to 10.0 micrograms per cubic meter, but mean concentrations in the residential area were slightly higher than those in the industrial area. When acidic aerosol concentrations were compared with concentrations of sulfate, nitrate, and chloride ions, a significant correlation was found between acidic aerosol and sulfate ion. The sum of the ion equivalents of the three types showed good correlation with the acidic aerosol equivalent during the whole period.

  4. Aerosol chemistry over a high altitude station at northeastern Himalayas, India.

    Directory of Open Access Journals (Sweden)

    Abhijit Chatterjee

    Full Text Available BACKGROUND: There is an urgent need for an improved understanding of the sources, distributions and properties of atmospheric aerosol in order to control the atmospheric pollution over northeastern Himalayas where rising anthropogenic interferences from rapid urbanization and development is becoming an increasing concern. METHODOLOGY/PRINCIPAL FINDINGS: An extensive aerosol sampling program was conducted in Darjeeling (altitude approximately 2200 meter above sea level (masl, latitude 27 degrees 01'N and longitude 88 degrees 15'E, a high altitude station in northeastern Himalayas, during January-December 2005. Samples were collected using a respirable dust sampler and a fine dust sampler simultaneously. Ion chromatograph was used to analyze the water soluble ionic species of aerosol. The average concentrations of fine and coarse mode aerosol were found to be 29.5+/-20.8 microg m(-3 and 19.6+/-11.1 microg m(-3 respectively. Fine mode aerosol dominated during dry seasons and coarse mode aerosol dominated during monsoon. Nitrate existed as NH(4NO(3 in fine mode aerosol during winter and as NaNO(3 in coarse mode aerosol during monsoon. Gas phase photochemical oxidation of SO(2 during premonsoon and aqueous phase oxidation during winter and postmonsoon were the major pathways for the formation of SO(4(2- in the atmosphere. Long range transport of dust aerosol from arid regions of western India was observed during premonsoon. The acidity of fine mode aerosol was higher in dry seasons compared to monsoon whereas the coarse mode acidity was higher in monsoon compared to dry seasons. Biomass burning, vehicular emissions and dust particles were the major types of aerosol from local and continental regions whereas sea salt particles were the major types of aerosol from marine source regions. CONCLUSIONS/SIGNIFICANCE: The year-long data presented in this paper provide substantial improvements to the heretofore poor knowledge regarding aerosol chemistry over

  5. Effects of a premolt calcium and low-energy molt program on laying hen behavior and heterophil-to-lymphocyte ratios.

    Science.gov (United States)

    Dickey, E R; Bregendahl, K; Stalder, K; Fitzgerald, R; Johnson, A K

    2010-11-01

    The objectives of this study were to compare the behaviors, postures, and heterophil-to-lymphocyte ratios (H:L) of laying hens housed in a cage system when offered a Ca premolt treatment and low-energy molt diets vs. a traditional feed withdrawal (FW) treatment during and after molt. A total of 144 Hy-Line W-36 hens (85 wk of age), housed 3 hens/cage (413 cm(2)/hen), were used. Hens were allotted to treatments according to a randomized complete block design, with the cage location and initial BW as the blocking criteria. Six treatments were compared in a 2 × 3 factorial arrangement with 2 Ca premolt treatments (fine or coarse) and 3 low-energy molt diets (FW, soybean hulls, or wheat middlings). The 2 Ca premolt treatments differed only in Ca particle size (fine was 0.14 mm and coarse was 2.27 mm mean diameter). Two postures and 5 behaviors were recorded and H:L was measured. Data were analyzed using the MIXED procedure of SAS, with P hens in the FW treatment were more active, and they ate and drank less compared with hens fed soybean hulls or wheat middlings, but there were no differences in aggression, nonnutritive pecking, or sitting. Drinking and aggression during and after molt were not different, but hens postmolt engaged in more sitting and feeding and less activity, nonnutritive pecking, and preening compared with during molt. There were no differences in H:L during or after molt. In conclusion, a Ca premolt treatment did not affect the behavior of the laying hen. The low-energy molt diets did not adversely affect behavior compared with FW and did not increase H:L; therefore, they could be useful alternatives for inducing molt in laying hens.

  6. Ambient Aerosol in Southeast Asia: High Resolution Aerosol Mass Spectrometer Measurements Over Oil Palm (Elaeis guineensis)

    Science.gov (United States)

    Phillips, G.; Dimarco, C.; Misztal, P.; Nemitz, E.; Farmer, D.; Kimmel, J.; Jimenez, J.

    2008-12-01

    The emission of organic compounds in the troposphere is important factor in the formation of secondary organic aerosol (SOA). A very large proportion of organic material emitted globally is estimated to arise from biogenic sources, with almost half coming from tropical and sub-tropical forests. Preliminary analyses of leave cuvette emission studies suggest that oil palm (Elaeis guineensis) is a significantly larger source of isoprene than tropical forest. Much larger sources of isoprene over oil palm allied with a larger anthropogenic component of local emissions contrast greatly with the remote tropical forest environment and therefore the character of SOA formed may differ significantly. These issues, allied with the high price of palm oil on international markets leading to increased use of land for oil palm production, could give rise to rapidly changing chemical and aerosol regimes in the tropics. It is therefore important to understand the current emissions and composition of organic aerosol over all important land-uses in the tropical environment. This in turn will lead to a greater understanding of the present, and to an improvement in predictive capacity for the future system. To help address these issues, a high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) was deployed in the Sabahmas (PPB OIL) oil palm plantation near Lahad Datu, in Eastern Sabah, as part of the field component of the Aerosol Coupling in the Earth System (ACES) project, part of the UK NERC APPRAISE program. This project was allied closely with measurements made of similar chemical species and aerosol components at a forest site in the Danum Valley as part of the UK Oxidant and Particle Photochemical Processes above a Southeast Asian tropical rainforest (OP3) project. Measurements of submicron non- refractory aerosol composition are presented along with some preliminary analysis of chemically resolved aerosol fluxes made with a new eddy covariance system, based on the

  7. Chemical composition and characteristics of ambient aerosols and rainwater residues during Indian summer monsoon: Insight from aerosol mass spectrometry

    Science.gov (United States)

    Chakraborty, Abhishek; Gupta, Tarun; Tripathi, Sachchida N.

    2016-07-01

    Real time composition of non-refractory submicron aerosol (NR-PM1) is measured via Aerosol mass spectrometer (AMS) for the first time during Indian summer monsoon at Kanpur, a polluted urban location located at the heart of Indo Gangetic Plain (IGP). Submicron aerosols are found to be dominated by organics followed by nitrate. Source apportionment of organic aerosols (OA) via positive matrix factorization (PMF) revealed several types of secondary/oxidized and primary organic aerosols. On average, OA are completely dominated by oxidized OA with a very little contribution from biomass burning OA. During rain events, PM1 concentration is decreased almost by 60%, but its composition remains nearly the same. Oxidized OA showed slightly more decrease than primary OAs, probably due to their higher hygroscopicity. The presence of organo nitrates (ON) is also detected in ambient aerosols. Apart from real-time sampling, collected fog and rainwater samples were also analyzed via AMS in offline mode and in the ICP-OES (Inductively coupled plasma - Optical emission spectrometry) for elements. The presence of sea salt, organo nitrates and sulfates has been observed. Rainwater residues are also dominated by organics but their O/C ratios are 15-20% lower than the observed values for ambient OA. Alkali metals such as Ca, Na, K are found to be most abundant in the rainwater followed by Zn. Rainwater residues are also found to be much less oxidized than the aerosols present inside the fog water, indicating presence of less oxidized organics. These findings indicate that rain can act as an effective scavenger of different types of pollutants even for submicron particle range. Rainwater residues also contain organo sulfates which indicate that some portion of the dissolved aerosols has undergone aqueous processing, possibly inside the cloud. Highly oxidized and possibly hygroscopic OA during monsoon period compared to other seasons (winter, post monsoon), indicates that they can act

  8. Assessing spaceborne lidar detection and characterization of aerosols near clouds using coincident airborne lidar and other measurements

    Science.gov (United States)

    Kacenelenbogen, M. S.; Redemann, J.; Russell, P. B.; Vaughan, M.; Omar, A. H.; Burton, S. P.; Rogers, R.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.

    2011-12-01

    The objectives are to 1) evaluate potential shortcomings in the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aerosol height detection concerning specific biomass burning smoke events informed by airborne High Spectral Resolution Lidar (HSRL) in different cloud environments and 2) study the lidar-derived atmospheric parameters in the vicinity of clouds for the cases where smoke is within or above clouds. In the case of light absorbing aerosols like biomass burning smoke, studies show that the greater the cloud cover below the aerosols, the more likely the aerosols are to heat the planet. An accurate aerosol height assumption is also crucial to a correct retrieval of aerosol chemical composition from passive space-based measurements (through the Single Scattering Albedo (SSA) and aerosol absorption coefficient, as exemplified by aerosol retrievals using the passive Ozone Monitoring Instrument (OMI)). Strong smoke events are recognized as very difficult to quantify from space using passive (MODIS, OMI etc...) or active (CALIOP) satellite sensors for different reasons. This study is performed through (i) the selection of smoke events with coincident CALIOP and airborne HSRL aerosol observations, with smoke presence determined according to the HSRL aerosol classification data, (ii) the order of such events by range of HSRL aerosol optical depth, total color ratio and depolarization ratio (the latter two informing on the size and shape of the particles) and the evaluation of CALIOP's detection, classification and retrieval performance for each event, (iii) the study of the HSRL (or CALIOP when available) atmospheric parameters (total color ratio, volume depolarization ratio, mean attenuated backscatter) in the vicinity of clouds for each smoke event.

  9. Sources and composition of urban aerosol particles

    Science.gov (United States)

    Vogt, M.; Johansson, C.; Mårtensson, M.; Struthers, H.; Ahlm, L.; Nilsson, D.

    2011-09-01

    From May 2008 to March 2009 aerosol emissions were measured using the eddy covariance method covering the size range 0.25 to 2.5 μm diameter (Dp) from a 105 m tower, in central Stockholm, Sweden. Supporting chemical aerosol data were collected at roof and street level. Results show that the inorganic fraction of sulfate, nitrate, ammonium and sea salt accounts for approximately 15% of the total aerosol mass traffic (as inferred from the ratio of the incremental concentrations of nitrogen oxides (NOx) and BC measured on a densely trafficked street) and the fluxes of non-volatile material at tower level are in close agreement, suggesting a traffic source of BC. We have estimated the emission factors (EFs) for non-volatile particles traffic activity data. Light (LDV) and heavy duty vehicle (HDV) EFs were estimated using multiple linear regression and reveal that for non-volatile particulate matter in the 0.25 to 0.6 μm Dp range, the EFHDV is approximately twice as high as the EFLDV, the difference not being statistically significant.

  10. Design of nanomaterial synthesis by aerosol processes.

    Science.gov (United States)

    Buesser, Beat; Pratsinis, Sotiris E

    2012-01-01

    Aerosol synthesis of materials is a vibrant field of particle technology and chemical reaction engineering. Examples include the manufacture of carbon blacks, fumed SiO(2), pigmentary TiO(2), ZnO vulcanizing catalysts, filamentary Ni, and optical fibers, materials that impact transportation, construction, pharmaceuticals, energy, and communications. Parallel to this, development of novel, scalable aerosol processes has enabled synthesis of new functional nanomaterials (e.g., catalysts, biomaterials, electroceramics) and devices (e.g., gas sensors). This review provides an access point for engineers to the multiscale design of aerosol reactors for the synthesis of nanomaterials using continuum, mesoscale, molecular dynamics, and quantum mechanics models spanning 10 and 15 orders of magnitude in length and time, respectively. Key design features are the rapid chemistry; the high particle concentrations but low volume fractions; the attainment of a self-preserving particle size distribution by coagulation; the ratio of the characteristic times of coagulation and sintering, which controls the extent of particle aggregation; and the narrowing of the aggregate primary particle size distribution by sintering.

  11. Mixing state of aerosols over the Indo-Gangetic Plain: Radiative forcing and heating rate

    Science.gov (United States)

    Srivastava, R.; Ramachandran, S.

    2012-12-01

    ratio is calculated from the geometry of core-shell particles, which depends on the mass and density of the core and shell. The size distribution parameters and refractive indices of different aerosol species are taken from OPAC database [3]. Different fractions of black carbon, water soluble and mineral dust aerosols involved in core-shell mixing emerge as the most probable mixing states over the IGP. Aerosol forcing for external mixing shows higher deviations from those for probable mixing cases during winter and pre-monsoon. The heating rate over Kanpur and Gandhi College in the lower troposphere is similar during pre-monsoon (March-May) ( 0.75 K day^{-1}) and monsoon (June-September) ( 0.5 K day^{-1}), while differences occur in other seasons [4]. Aerosol heating rate profiles exhibit primary and secondary peaks over the IGP and exhibit seasonal variations. Details on the calculations of aerosol mixing states over IGP, the impact of aerosol mixing state on aerosol forcing and heating rate will be discussed. References: [1] Intergovernmental panel on climate change (2007), Solomon S. et al. (eds.), Cambridge Univ. Press, NewYork. [2] Holben B. N., et al. (2001), J. Geophys. Res., 106(D11), 12067-12097. [3] Hess M., P. Koepke, I. Schult (1998), Bull. Am. Meteorol. Soc., 79, 831-844. [4] Srivastava R., S. Ramachandran (2012), Q. J. R. Meteorol. Soc., 138, doi:10.1002/qj.1958.

  12. Photochemical aerosols in warm exoplanetary atmospheres

    Science.gov (United States)

    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. Topics in current aerosol research

    CERN Document Server

    Hidy, G M

    1971-01-01

    Topics in Current Aerosol Research deals with the fundamental aspects of aerosol science, with emphasis on experiment and theory describing highly dispersed aerosols (HDAs) as well as the dynamics of charged suspensions. Topics covered range from the basic properties of HDAs to their formation and methods of generation; sources of electric charges; interactions between fluid and aerosol particles; and one-dimensional motion of charged cloud of particles. This volume is comprised of 13 chapters and begins with an introduction to the basic properties of HDAs, followed by a discussion on the form

  14. Aerosol-Cloud-Precipitation Interactions over Indo-Gangetic Basin

    Science.gov (United States)

    Tsay, S.-C.; Lau, K. .; Holben, B. N.; Hsu, N. C.; Bhartia, P. K.

    2005-01-01

    About 60% of world population reside in Asia, in term of which sheer population density presents a major environmental stress. Economic expansion in this region is, in fact, accompanied by increases in bio-fuel burning, industrial pollution, and land cover and land use changes. With a growth rate of approx. 8%/yr for Indian economy, more than 600 million people from Lahore, Pakistan to Calcutta, India over the Indo-Gangetic Basin have particularly witnessed increased frequencies of floods and droughts as well as a dramatic increase in atmospheric loading of aerosols (i.e., anthropogenic and natural aerosol) in recent decades. This regional change (e.g., aerosol, cloud, precipitation, etc.) will constitute a vital part of the global change in the 21st century. Better understanding of the impacts of aerosols in affecting monsoon climate and water cycles is crucial in providing the physical basis to improve monsoon climate prediction and for disaster mitigation. Based on climate model simulations, absorbing aerosols (dust and black carbon) play a critical role in affecting interannual and intraseasonal variability of the Indian monsoon. An initiative on the integrated (aerosols, clouds, and precipitation) measurements approach over the Indo-Gangetic Basin will be discussed. An array of ground-based (e.g., AERONET, MPLNET, SMART-COMMIT, etc.) and satellite (e.g., Terra, A-Train, etc.) sensors will be utilized to acquire aerosol characteristics, sources/sinks, and transport processes during the pre-monsoon (April-May, aerosol forcing) season, and to obtain cloud and precipitation properties during the monsoon (May-June, water cycle response) season. Close collaboration with other international programs, such as ABC, CLIVAR, GEWEX, and CEOP in the region is anticipated.

  15. Mechanisms of Formation of Secondary Organic Aerosols and Implications for Global Radiative Forcing

    Energy Technology Data Exchange (ETDEWEB)

    Seinfeld, John H. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2011-12-02

    Organic material constitutes about 50% of global atmospheric aerosol mass, and the dominant source of organic aerosol is the oxidation of volatile hydrocarbons, to produce secondary organic aerosol (SOA). Understanding the formation of SOA is crucial to predicting present and future climate effects of atmospheric aerosols. The goal of this program is to significantly increase our understanding of secondary organic aerosol (SOA) formation in the atmosphere. Ambient measurements indicate that the amount of SOA in the atmosphere exceeds that predicted in current models based on existing laboratory chamber data. This would suggest that either the SOA yields measured in laboratory chambers are understated or that all major organic precursors have not been identified. In this research program we are systematically exploring these possibilities.

  16. Airborne measurements of aerosol optical properties related to early spring transport of mid-latitude sources into the Arctic

    Directory of Open Access Journals (Sweden)

    R. Adam de Villiers

    2009-12-01

    Full Text Available Airborne lidar and in-situ measurements of the aerosol properties were conducted between Svalbard Island and Scandinavia in April 2008. Evidence of aerosol transport from Europe and Asia is given. The analysis of the aerosol optical properties based on a multiwavelength lidar (355, 532, 1064 nm including depolarization at 355 nm aims at distinguishing the role of the different aerosol sources (Siberian wild fires, Eastern Asia and European anthropogenic emissions. Combining, first aircraft measurements, second FLEXPART simulations with a calculation of the PBL air fraction originating from the three different mid-latitude source regions, and third level-2 CALIPSO data products (i.e. backscatter coefficient, depolarisation and color ratio in aerosol layers along the transport pathways, appears a valuable approach to identify the role of the different aerosol sources even after a transport time larger than 4 days. Above Asia, CALIPSO data indicate more depolarisation (up to 15% and largest color ratio (>0.5 for the northeastern Asia emissions (i.e. an expected mixture of Asian pollution and dust, while low depolarisation together with smaller and quasi constant color ratio (≈0.3 are observed for the Siberian biomass burning emissions. A similar difference is visible between two layers observed by the aircraft above Scandinavia. The analysis of the time evolution of the aerosol optical properties revealed by CALIPSO between Asia and Scandinavia shows a gradual decrease of the aerosol backscatter, depolarisation ratio and color ratio which suggests the removal of the largest particles in the accumulation mode. A similar study conducted for a European plume has shown aerosol optical properties intermediate between the two Asian sources with color ratio never exceeding 0.4 and moderate depolarisation ratio being always less than 8%, i.e. less aerosol from the accumulation mode.

  17. The impact of biogenic carbon emissions on aerosol absorption inMexico City

    Energy Technology Data Exchange (ETDEWEB)

    Marley, N; Gaffney, J; Tackett, M J; Sturchio, N; Hearty, L; Martinez, N; Hardy, K D; Machany-Rivera, A; Guilderson, T P; MacMillan, A; Steelman, K

    2009-02-24

    In order to determine the wavelength dependence of atmospheric aerosol absorption in the Mexico City area, the absorption angstrom exponents (AAEs) were calculated from aerosol absorption measurements at seven wavelengths obtained with a seven-channel aethalometer during two field campaigns, the Mexico City Metropolitan Area study in April 2003 (MCMA 2003) and the Megacity Initiative: Local and Global Research Observations in March 2006 (MILAGRO). The AAEs varied from 0.76 to 1.56 in 2003 and from 0.54 to 1.52 in 2006. The AAE values determined in the afternoon were consistently higher than the corresponding morning values, suggesting the photochemical formation of absorbing secondary organic aerosols (SOA) in the afternoon. The AAE values were compared to stable and radiocarbon isotopic measurements of aerosol samples collected at the same time to determine the sources of the aerosol carbon. The fraction of modern carbon (fM) in the aerosol samples, as determined from {sup 14}C analysis, showed that 70% of the carbonaceous aerosols in Mexico City were from modern sources, indicating a significant impact from biomass burning during both field campaigns. The {sup 13}C/{sup 12}C ratios of the aerosol samples illustrate the significant impact of Yucatan forest fires (C-3 plants) in 2003 and local grass fires (C-4 plants) at site T1 in 2006. A direct comparison of the fM values, stable carbon isotope ratios, and calculated aerosol AAEs suggested that the wavelength dependence of the aerosol absorption was controlled by the biogenically derived aerosol components.

  18. Nabro aerosol evolution observed jointly by lidars at a mid-latitude site and CALIPSO

    Science.gov (United States)

    Zhuang, J.; Yi, F.

    2016-09-01

    Evolution of the Nabro volcanic aerosols from initially-localized plumes to a decaying hemispherically-covered layer was jointly observed by ground-based lidars at Wuhan (30.5°N, 114.4°E), China and CALIPSO. During the aerosol plume formation period, from the Nabro eruption to early July 2011, the lidar backscatter ratio related to the Nabro aerosols above Wuhan varied strongly both in vertical structure and intensity, suggesting that the Nabro aerosol distribution was horizontally inhomogeneous. The stratospheric aerosol optical depth (AOD) from CALIPSO shows that the Nabro plume first circled around the Asian monsoon anticyclone and then gradually fulfilled the whole anticyclone area with a net aerosol enhancement, which may reflect a gas-particle conversion (from sulfur dioxide gas) and/or particle injection from the upper troposphere. During the horizontal dispersion period, from early July to mid-August 2011, the stratospheric AOD over Wuhan declined rapidly since the Nabro particles were transported throughout the northern hemisphere. A nearly horizontally-uniform volcanic aerosol layer was formed. During the local cleansing period, from mid-August to the end of 2011, the Nabro aerosol layer over Wuhan had a single-peak structure and decayed uniformly. The corresponding e-folding decay time for the layer AOD is ∼130 days. The lidar measurements at Wuhan gave a small depolarization ratio and large backscatter-related Ångström exponent for the Nabro aerosols on 8 July, suggesting that the majority of these aerosols were spherical and small. The effective radius and total mass for the Nabro aerosol particles were estimated to be ∼0.26 μm and ∼0.32 Tg respectively.

  19. The impact of biogenic carbon emissions on aerosol absorption in Mexico City

    Science.gov (United States)

    Marley, N. A.; Gaffney, J. S.; Tackett, M. J.; Sturchio, N. C.; Heraty, L.; Martinez, N.; Hardy, K. D.; Machany-Rivera, A.; Guilderson, T.; MacMillan, A.; Steelman, K.

    2008-10-01

    In order to determine the wavelength dependence of atmospheric aerosol absorption in the Mexico City area, the absorption Ångstrom exponents (AAEs) were calculated from aerosol absorption measurements at seven wavelengths obtained with a seven-channel aethalometer during two field campaigns, the Mexico City Metropolitan Area study in April 2003 (MCMA 2003) and the Megacity Initiative: Local and Global Research Observations in March 2006 (MILAGRO). The AAEs varied from 0.76 to 1.56 in 2003 and from 0.54 to 1.52 in 2006. The AAE values determined in the afternoon were consistently higher than the corresponding morning values, suggesting the photochemical formation of absorbing secondary organic aerosols (SOA) in the afternoon. The AAE values were compared to stable and radiocarbon isotopic measurements of aerosol samples collected at the same time to determine the sources of the aerosol carbon. The fraction of modern carbon (fM) in the aerosol samples, as determined from 14C analysis, showed that 70% of the carbonaceous aerosols in Mexico City were from modern sources, indicating a significant impact from biomass burning during both field campaigns. The 13C/12C ratios of the aerosol samples illustrate the significant impact of Yucatan forest fires (C-3 plants) in 2003 and local grass fires (C-4 plants) at site T1 in 2006. A direct comparison of the fM values, stable carbon isotope ratios, and calculated aerosol AAEs suggested that the wavelength dependence of the aerosol absorption was controlled by the biogenically derived aerosol components.

  20. Development towards a global operational aerosol consensus: basic climatological characteristics of the International Cooperative for Aerosol Prediction Multi-Model Ensemble (ICAP-MME

    Directory of Open Access Journals (Sweden)

    W. R. Sessions

    2014-06-01

    Full Text Available Over the past several years, there has been a rapid development in the number and quality of global aerosol models intended for operational forecasting use. Indeed, most centers with global numerical weather prediction (NWP capabilities have some program for aerosol prediction. These aerosol models typically have differences in their underlying meteorology as well as aerosol sources, sinks, microphysics and transformations. However, like similar diversity in aerosol climate models, the aerosol forecast models have fairly similar overall bulk error statistics for aerosol optical thickness (AOT-one of the few aerosol metrics that is globally available. Experience in climate and weather prediction has shown that in situations such as this where there are several independent models, a multi-model ensemble or consensus will be top performing in many key error metrics. Further, multi-model ensembles provide a highly valuable tool for forecasters attempting to predict severe aerosol events. Here we present the first steps in developing a global multi-model aerosol forecasting ensemble intended for eventual operational and basic research use. Drawing from members of the International Cooperative for Aerosol Prediction (ICAP latest generation of quasi-operational aerosol models, five day AOT forecasts are analyzed for December 2011 through November 2012 from four institutions: ECMWF, JMA, NASA GSFC, and NRL/FNMOC. For dust, we also include the NOAA NGAC product in our analysis. The Barcelona Supercomputing Centre (NMMC and UK Met office dust product have also recent become available with ICAP, but have insufficient data to be included in this analysis period. A simple consensus ensemble of member and mean AOT fields for modal species (e.g., fine and coarse mode, and a separate dust ensemble is used to create the ICAP Multi-Model Ensemble (ICAP-MME. The ICAP-MME is run daily at 0Z for 6 hourly forecasts out to 120 h. Basing metrics on comparisons to 21

  1. Development towards a global operational aerosol consensus: basic climatological characteristics of the International Cooperative for Aerosol Prediction Multi-Model Ensemble (ICAP-MME)

    Science.gov (United States)

    Sessions, W. R.; Reid, J. S.; Benedetti, A.; Colarco, P. R.; da Silva, A.; Lu, S.; Sekiyama, T.; Tanaka, T. Y.; Baldasano, J. M.; Basart, S.; Brooks, M. E.; Eck, T. F.; Iredell, M.; Hansen, J. A.; Jorba, O. C.; Juang, H.-M. H.; Lynch, P.; Morcrette, J.-J.; Moorthi, S.; Mulcahy, J.; Pradhan, Y.; Razinger, M.; Sampson, C. B.; Wang, J.; Westphal, D. L.

    2014-06-01

    Over the past several years, there has been a rapid development in the number and quality of global aerosol models intended for operational forecasting use. Indeed, most centers with global numerical weather prediction (NWP) capabilities have some program for aerosol prediction. These aerosol models typically have differences in their underlying meteorology as well as aerosol sources, sinks, microphysics and transformations. However, like similar diversity in aerosol climate models, the aerosol forecast models have fairly similar overall bulk error statistics for aerosol optical thickness (AOT)-one of the few aerosol metrics that is globally available. Experience in climate and weather prediction has shown that in situations such as this where there are several independent models, a multi-model ensemble or consensus will be top performing in many key error metrics. Further, multi-model ensembles provide a highly valuable tool for forecasters attempting to predict severe aerosol events. Here we present the first steps in developing a global multi-model aerosol forecasting ensemble intended for eventual operational and basic research use. Drawing from members of the International Cooperative for Aerosol Prediction (ICAP) latest generation of quasi-operational aerosol models, five day AOT forecasts are analyzed for December 2011 through November 2012 from four institutions: ECMWF, JMA, NASA GSFC, and NRL/FNMOC. For dust, we also include the NOAA NGAC product in our analysis. The Barcelona Supercomputing Centre (NMMC) and UK Met office dust product have also recent become available with ICAP, but have insufficient data to be included in this analysis period. A simple consensus ensemble of member and mean AOT fields for modal species (e.g., fine and coarse mode, and a separate dust ensemble) is used to create the ICAP Multi-Model Ensemble (ICAP-MME). The ICAP-MME is run daily at 0Z for 6 hourly forecasts out to 120 h. Basing metrics on comparisons to 21 regionally

  2. Aerosol-cloud-precipitation interactions: A challenging problem in regional environment and climate research

    Institute of Scientific and Technical Information of China (English)

    P.C.S.Devara; M.G.Manoj

    2013-01-01

    Aerosols affect clouds in two broad ways:(i) presence of more number of aerosols leads to formation of more smaller droplets,and reduces coalescence,resulting in brighter clouds that reflect more solar energy back to space,hence they contribute to cooling of the Earth's surface and (ii) numerous smaller cloud droplets tend to reduce precipitation and change the extent of cloud cover and increase cloud lifetime and albedo.One of our recent studies on aerosols over the Indo-Gangetic Plains (IGP) relative to the pristine oceans to the south of Indian Ocean showed that highly absorbing aerosols could potentially lead to the revival of active condition preceded by long break.The absorption of solar radiation by aerosols such as black carbon and desert dust produces surface cooling and local stabilization of lower atmosphere.This stability effect is overcome by the enhanced moisture convergence due to the meridional gradient of aerosol-induced heating.In some other studies,we showed association between cloud thickness and cloud to sub-cloud ratio (SCR),aerosol variability (in terms of aerosol optical depth and aerosol index) and monsoon precipitation and climate over regional scale.This paper provides an overview of some salient results that have been obtained from the studies conducted,using the ground-and space-based active and passive remote sensing techniques,at the Indian Institute of Tropical Meteorology (IITM),Pune,India in the recent decade.

  3. Vertically Resolved Aerosol Optical Properties over the ARM SGP Site

    Science.gov (United States)

    Schmid, B.; Jonsson, H.; Strawa, A.; Provencal, B.; Covert, D.; Arnott, P.; Bucholtz, A.; Pilewskie, P.; Pommier, J.; Rissman, T.

    2003-01-01

    In order to meet one of its goals - to relate observations of radiative fluxes and radiances to the atmospheric composition - the Department of Energy's Atmospheric Radiation Measurement (ARM) program has pursued measurements and modeling activities that attempt to determine how aerosols impact atmospheric radiative transfer, both directly and indirectly. However, significant discrepancies between aerosol properties measured in situ or remotely remain. To this end, the ARM program will conduct an Aerosol Intensive Operational Period (IOP) in May 2003 at the ARM Southern Great Plains (SGP) site in north central Oklahoma. The IOP involves airborne measurements from two airplanes over the heavily instrumented SGP site. We will give an overview of early airborne results obtained aboard Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft. The aircraft will carry instrumentation to perform in-situ measurements of aerosol absorption, scattering, extinction and particle size including such novel techniques as the photoacoustic and cavity ring-down methods. Aerosol optical depth and extinction will be measured with the NASA Ames Airborne Tracking 14-channel sunphotometer. Furthermore up- and downwelling solar (broadband and spectral) and infrared radiation will be measured using three different instruments. The up-looking radiation instruments will be mounted on a newly developed stabilized platform, which will keep the instruments level up to aircraft pitch and roll angles of 10 degrees. Additional effort will be directed toward measurement of cloud condensation nucleus concentration as a function of supersaturation and relating CCN concentration to aerosol composition and size distribution. This relation is central to description of the aerosol indirect effect.

  4. Multi-Sensor Ensemble Aerosol Assimilation - CERES, MODIS and VIIRS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Accurate estimates of the radiative effects of clouds and aerosols are essential for an understanding of the Earth's climate system. Under the EOS program, NASA has...

  5. Model representations of aerosol layers transported from North America over the Atlantic Ocean during the Two-Column Aerosol Project

    Energy Technology Data Exchange (ETDEWEB)

    Fast, Jerome D. [Pacific Northwest National Laboratory, Richland Washington USA; Berg, Larry K. [Pacific Northwest National Laboratory, Richland Washington USA; Zhang, Kai [Pacific Northwest National Laboratory, Richland Washington USA; Easter, Richard C. [Pacific Northwest National Laboratory, Richland Washington USA; Ferrare, Richard A. [NASA Langley Research Center, Hampton Virginia USA; Hair, Johnathan W. [NASA Langley Research Center, Hampton Virginia USA; Hostetler, Chris A. [NASA Langley Research Center, Hampton Virginia USA; Liu, Ying [Pacific Northwest National Laboratory, Richland Washington USA; Ortega, Ivan [Department of Chemistry, Colorado University, Boulder Colorado USA; Sedlacek, Arthur [Brookhaven National Laboratory, Upton New York USA; Shilling, John E. [Pacific Northwest National Laboratory, Richland Washington USA; Shrivastava, Manish [Pacific Northwest National Laboratory, Richland Washington USA; Springston, Stephen R. [Brookhaven National Laboratory, Upton New York USA; Tomlinson, Jason M. [Pacific Northwest National Laboratory, Richland Washington USA; Volkamer, Rainer [Department of Chemistry, Colorado University, Boulder Colorado USA; Wilson, Jacqueline [Pacific Northwest National Laboratory, Richland Washington USA; Zaveri, Rahul A. [Pacific Northwest National Laboratory, Richland Washington USA; Zelenyuk, Alla [Pacific Northwest National Laboratory, Richland Washington USA

    2016-08-22

    The ability of the Weather Research and Forecasting model with chemistry (WRF-Chem) version 3.7 and the Community Atmosphere Model version 5.3 (CAM5) in simulating profiles of aerosol properties is quantified using extensive in situ and remote sensing measurements from the Two Column Aerosol Project (TCAP) conducted during July of 2012. TCAP was supported by the U.S. Department of Energy’s Atmospheric Radiation Measurement program and was designed to obtain observations within two atmospheric columns; one fixed over Cape Cod, Massachusetts and the other several hundred kilometers over the ocean. The performance is quantified using most of the available aircraft and surface measurements during July, and two days are examined in more detail to identify the processes responsible for the observed aerosol layers. The higher resolution WRF-Chem model produced more aerosol mass in the free troposphere than the coarser resolution CAM5 model so that the fraction of aerosol optical thickness above the residual layer from WRF-Chem was more consistent with lidar measurements. We found that the free troposphere layers are likely due to mean vertical motions associated with synoptic-scale convergence that lifts aerosols from the boundary layer. The vertical displacement and the time period associated with upward transport in the troposphere depend on the strength of the synoptic system and whether relatively high boundary layer aerosol concentrations are present where convergence occurs. While a parameterization of subgrid scale convective clouds applied in WRF-Chem modulated the concentrations of aerosols aloft, it did not significantly change the overall altitude and depth of the layers.

  6. Path radiance technique for retrieving aerosol optical thickness over land

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Guoyong [Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Catonsville (United States); Tsay, Si-Chee [NASA Goddard Space Flight Center, Greenbelt, Maryland (United States); Cahalan, Robert F. [Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Catonsville (United States); NASA Goddard Space Flight Center, Greenbelt, Maryland (United States); Oreopoulos, Lazaros [Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Catonsville (United States)

    1999-12-27

    The key issue in retrieving aerosol optical thickness over land from shortwave satellite radiances is to identify and separate the signal due to scattering by a largely transparent aerosol layer from the noise due to reflection by the background surface, where the signal is relatively uniform compared to the highly inhomogeneous surface contribution. Sensitivity studies in aerosol optical thickness retrievals reveal that the apparent reflectance at the top of the atmosphere is very susceptible to the surface reflectance, especially when aerosol optical thickness is small. Uncertainties associated with surface reflectance estimation can greatly amplify the error of the aerosol optical thickness retrieval. To reduce these uncertainties, we have developed a ''path radiance'' method to retrieve aerosol optical thickness over land by extending the traditional technique that uses the ''dark object'' approach to extract the aerosol signal. This method uses the signature of the correlation of visible and middle-IR reflectance at the surface and couples the correlation with the atmospheric effect. We have applied this method to a Landsat TM (Thematic Mapper) image acquired over the Oklahoma southern Great Plains site of the Department of Energy Atmospheric Radiation Measurement (ARM) program on September 27, 1997, a very clear day (aerosol optical thickness of 0.07 at 0.5 {mu}m) during the first Landsat Intensive Observation Period. The retrieved mean aerosol optical thickness for TM band 1 at 0.49 {mu}m and band 3 at 0.66 {mu}m agree very well with the ground-based Sun photometer measurements at the ARM site. The ability to retrieve small aerosol optical thickness makes this path radiance technique promising. More importantly, the path radiance is relatively insensitive to surface inhomogeneity. The retrieved mean path radiances in reflectance units have very small standard deviations for both TM blue and red bands. This small

  7. Aerosol classification from airborne HSRL and comparisons with the CALIPSO vertical feature mask

    Directory of Open Access Journals (Sweden)

    S. P. Burton

    2013-02-01

    Full Text Available Aerosol classification products from the NASA Langley Research Center (LaRC airborne High Spectral Resolution Lidar (HSRL-1 on the NASA B200 aircraft are compared with coincident V3.01 aerosol classification products from the CALIOP instrument on the CALIPSO satellite. For CALIOP, aerosol classification is a key input to the aerosol retrieval, and must be inferred using aerosol loading-dependent observations and location information. In contrast, HSRL-1 makes direct measurements of aerosol intensive properties, including the lidar ratio, that provide information on aerosol type. In this study, comparisons are made for 109 underflights of the CALIOP orbit track. We find that 62% of the CALIOP marine layers and 54% of the polluted continental layers agree with HSRL-1 classification results. In addition, 80% of the CALIOP desert dust layers are classified as either dust or dusty mix by HSRL-1. However, agreement is less for CALIOP smoke (13% and polluted dust (35% layers. Specific case studies are examined, giving insight into the performance of the CALIOP aerosol type algorithm. In particular, we find that the CALIOP polluted dust type is overused due to an attenuation-related depolarization bias. Furthermore, the polluted dust type frequently includes mixtures of dust plus marine aerosol. Finally, we find that CALIOP's identification of internal boundaries between different aerosol types in contact with each other frequently do not reflect the actual transitions between aerosol types accurately. Based on these findings, we give recommendations which may help to improve the CALIOP aerosol type algorithms.

  8. Raman Lidar Measurements of Aerosol Extinction and Backscattering. Report 1; Methods and Comparisons

    Science.gov (United States)

    Ferrare, R. A.; Melfi, S. H.; Whiteman, D. N.; Evans, K. D.; Leifer, R.

    1998-01-01

    This paper examines the aerosol backscattering and extinction profiles measured at night by the NASA Goddard Space Flight Center Scanning Raman Lidar (SRL) during the remote cloud sensing (RCS) intensive operations period (IOP) at the Department of Energy Atmospheric Radiation Measurement (ARM) southern Great Plains (SGP) site in April 1994. These lidar data are used to derive aerosol profiles for altitudes between 0.0 1 5 and 5 km. Since this lidar detects Raman scattering from nitrogen and oxygen molecules as well as the elastic scattering from molecules and aerosols, it measures both aerosol backscattering and extinction simultaneously. The aerosol extinction/backscattering ratio varied between approximately 30 sr and 75 sr at 351 nm. Aerosol optical thicknesses derived by integrating the lidar profiles of aerosol extinction measured at night between 0. I and 5 km are found to be about 10-40% lower than those measured by a Sun photometer during the day. This difference is attributed to the contribution by stratospheric aerosols not included in the lidar estimates as well as to diurnal differences in aerosol properties and concentrations. Aerosol profiles close to the surface were acquired by pointing the lidar nearly horizontally. Measurements of aerosol scattering from a tower-mounted nephelometer are found to be 40% lower than lidar measurements of aerosol extinction over a wide range of relative humidities even after accounting for the difference in wavelengths. The reasons for this difference are not clear but may be due to the inability of the nephelometer to accurately measure scattering by large particles.

  9. Aerosol quantification with the Aerodyne Aerosol Mass Spectrometer: detection limits and ionizer background effects

    Directory of Open Access Journals (Sweden)

    S. Borrmann

    2009-02-01

    Full Text Available Systematic laboratory experiments were performed to investigate quantification of various species with two versions of the Aerodyne Aerosol Mass Spectrometer, a Quadrupole Aerosol Mass Spectrometer (Q-AMS and a compact Time-of-Flight Aerosol Mass Spectrometer (c-ToF-AMS. Here we present a new method to continuously determine the detection limits of the AMS analyzers during regular measurements, yielding detection limit (DL information under various measurement conditions. Minimum detection limits range from 0.03 μg m−3 (nitrate, sulfate, and chloride up to 0.5 μg m−3 (organics for the Q-AMS. Those of the c-ToF-AMS are found between 0.003 μg m−3 (nitrate, sulfate and 0.03 μg m−3 (ammonium, organics. The DL values found for the c-ToF-AMS were ~10 times lower than those of the Q-AMS, mainly due to differences in ion duty cycle. Effects causing an increase of the detection limits include long-term instrument contamination, measurement of high aerosol mass concentrations and short-term instrument history. The self-cleaning processes which reduce the instrument background after measurement of large aerosol concentrations as well as the influences of increased instrument background on mass concentration measurements are discussed. Finally, improvement of detection limits by extension of averaging time intervals, selected or reduced ion monitoring, and variation of particle-to-background measurement ratio are investigated.

  10. Hand calculations for transport of radioactive aerosols through sampling systems.

    Science.gov (United States)

    Hogue, Mark; Thompson, Martha; Farfan, Eduardo; Hadlock, Dennis

    2014-05-01

    Workplace air monitoring programs for sampling radioactive aerosols in nuclear facilities sometimes must rely on sampling systems to move the air to a sample filter in a safe and convenient location. These systems may consist of probes, straight tubing, bends, contractions and other components. Evaluation of these systems for potential loss of radioactive aerosols is important because significant losses can occur. However, it can be very difficult to find fully described equations to model a system manually for a single particle size and even more difficult to evaluate total system efficiency for a polydispersed particle distribution. Some software methods are available, but they may not be directly applicable to the components being evaluated and they may not be completely documented or validated per current software quality assurance requirements. This paper offers a method to model radioactive aerosol transport in sampling systems that is transparent and easily updated with the most applicable models. Calculations are shown with the R Programming Language, but the method is adaptable to other scripting languages. The method has the advantage of transparency and easy verifiability. This paper shows how a set of equations from published aerosol science models may be applied to aspiration and transport efficiency of aerosols in common air sampling system components. An example application using R calculation scripts is demonstrated. The R scripts are provided as electronic attachments.

  11. Aerosol absorption and radiative forcing

    Directory of Open Access Journals (Sweden)

    P. Stier

    2007-05-01

    Full Text Available We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006 significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA radiative forcing clear-sky from –0.79 to –0.53 W m−2 (33% and all-sky from –0.47 to –0.13 W m−2 (72%. Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m−2 (36% clear-sky and of 0.12 W m−2 (92% all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W

  12. New insights on aerosol sources and properties of Organics in the west Mediterranean basin

    Science.gov (United States)

    Nicolas, José B.; Sciare, Jean; Petit, Jean-Eudes; Bonnaire, Nicolas; Féron, Anais; Dulac, François; Hamonou, Eric; Gros, Valérie; Mallet, Marc; Lambert, Dominique; Sauvage, Stéphane; Léonardis, Thierry; Tison, Emmanuel; Colomb, Aurélie; Fresney, Evelyn; Pichon, Jean-Marc; Bouvier, Laetitia; Bourrianne, Thierry; Roberts, Gregory

    2013-04-01

    The Mediterranean basin exhibits high PM concentrations for a marine area, in particular during the dry season (summer), associated with high photochemistry. The large population of the basin is impacted by both natural and anthropogenic aerosols of various sources from Europe and North Africa. Simulations predict significant climate changes in that area, with less precipitation and hotter temperatures, reinforced by an increasing anthropogenic pressure, which will be linked by higher emissions of pollutants and also by higher impacts on the health. Nevertheless the aerosol models in that area currently suffer from large uncertainties, due to a lack of knowledge in organic aerosol (OA) sources and processes. As part of the French program ChArMEx (The Chemistry-Aerosol Mediterranean Experiment, http://charmex.lsce.ipsl.fr), a 5-week intensive campaign has been performed in June - July 2012 at the new Cape Corsica station (see Dulac et al. in that session), and aiming at a better characterization of anthropogenic versus biogenic aerosols, long range transport versus local influence, with a focus on fine OA. A complete instrumental strategy was deployed thanks to the contribution of a large French community: PM1 concentration every 6 min with a TEOM-FDMS 1405 (Thermo), major aerosol components in PM1 every 30 min (Organics, SO4, NO3, NH4) by Aerosol Chemical Speciation Monitor (Aerodyne), Equivalent Black Carbon every 5 min with a 7-? aethalometer AE31 (Magee Scientific), on-line major anions and cations (incl. light organics like oxalate & MSA) every 10 min with Particle-Into-Liquid Sampler (PILS, Metrohm) coupled with Ion Chromatographs (Dionex), on-line water-soluble organic carbon (WSOC) every 4 min with a PILS (Applikon) coupled with a Total Organic Carbon instrument (Ionics). Filter sampling in PM2.5 and PM10 was also performed every 12h for quality purposes (PM, EC/OC, ions) and for complementary measurements (metals by ICP-MS and organic tracers by LC

  13. Pressure Ratio to Thermal Environments

    Science.gov (United States)

    Lopez, Pedro; Wang, Winston

    2012-01-01

    A pressure ratio to thermal environments (PRatTlE.pl) program is a Perl language code that estimates heating at requested body point locations by scaling the heating at a reference location times a pressure ratio factor. The pressure ratio factor is the ratio of the local pressure at the reference point and the requested point from CFD (computational fluid dynamics) solutions. This innovation provides pressure ratio-based thermal environments in an automated and traceable method. Previously, the pressure ratio methodology was implemented via a Microsoft Excel spreadsheet and macro scripts. PRatTlE is able to calculate heating environments for 150 body points in less than two minutes. PRatTlE is coded in Perl programming language, is command-line-driven, and has been successfully executed on both the HP and Linux platforms. It supports multiple concurrent runs. PRatTlE contains error trapping and input file format verification, which allows clear visibility into the input data structure and intermediate calculations.

  14. Characterization of aerosol composition, concentrations, and sources at Baengnyeong Island, Korea using an aerosol mass spectrometer

    Science.gov (United States)

    Lee, Taehyoung; Choi, Jinsoo; Lee, Gangwoong; Ahn, Junyoung; Park, Jin Soo; Atwood, Samuel A.; Schurman, Misha; Choi, Yongjoo; Chung, Yoomi; Collett, Jeffrey L.

    2015-11-01

    To improve understanding of the sources and chemical properties of particulate pollutants on the western side of the Korean Peninsula, an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) measured non-refractory fine (PM1) particles from May to November, 2011 at Baengnyeong Island, South Korea. Organic matter and sulfate were generally the most abundant species and exhibited maximum concentrations of 36 μg/m3 and 39 μg/m3, respectively. Nitrate concentrations peaked at 32 μg/m3 but were typically much lower than sulfate and organic matter concentrations. May, September, October, and November featured the highest monthly average concentrations, with lower concentrations typically observed from June through August. Potential source contribution function (PSCF) analysis and individual case studies revealed that transport from eastern China, an area with high SO2 emissions, was associated with high particulate sulfate concentrations at the measurement site. Observed sulfate aerosol sometimes was fully neutralized by ammonium but often was acidic; the average ammonium to sulfate molar ratio was 1.49. Measured species size distributions revealed a range of sulfate particle size distributions with modes between 100 and 600 nm. Organic aerosol source regions were widespread, including contributions from eastern China and South Korea. Positive matrix factorization (PMF) analysis indicated three "factors," or types of organic aerosol, comprising one primary, hydrocarbon-like organic aerosol (HOA) and two oxidized organic aerosol (OOA) components, including a more oxidized (MO-OOA) and a less oxidized (LO-OOA) oxidized organic aerosol. On average, HOA and OOA contributed 21% and 79% of the organic mass (OM), respectively, with the MO-OOA fraction nearly three times as abundant as the LO-OOA fraction. Biomass burning contributions to observed OM were low during the late spring/early summer agricultural burning season in eastern China, since

  15. Growing up MODIS: Towards a mature aerosol climate data record

    Science.gov (United States)

    Levy, Robert C.

    2013-05-01

    Aerosols are major players within the Earth's climate system, affecting the radiation budget, clouds and the hydrological cycle. In high concentrations near the surface, aerosols (or particulate matter, PM) affect visibility, impact air quality, and can contribute to poor health. Among others, Yoram Kaufman recognized the importance of aerosols to climate, and helped to design new instrumentation and algorithms to retrieve and quantify global aerosol properties. One instrument, known as the Moderate Imaging Resolution Spectro-radiometer (MODIS), was deployed on the AM-1 satellite (later known as Terra), part of NASA's Earth Observing System (EOS). In 1998, armed with an M.S. and job experience in neither aerosols nor satellites, I was looking for a new job. I somehow found my way to the MODIS Aerosol team. It was only a year before Terra launch, and most major decisions about the MODIS aerosol retrieval algorithms had been finalized. Since then, we worked through launch, initial evaluation of the product with AERONET and field deployments, and continued efforts to understand the product and refine retrieval algorithms. I have had opportunities to participate in field experiments, write papers, and earn my PhD. The "second generation" algorithm for aerosol retrieval over land has been hugely successful. We have collected nearly a half-million collocations with AERONET and other dataseis, made new discoveries, and have contributed to research and operational projects globally. Due to the dedication of the entire team, the MODIS aerosol product now is one of the highlights of NASA's EOS program. It is used for climate research and air quality forecasting, as well for applications not even considered before the MODIS era. More recently, a focus is on stitching the MODIS aerosol product into the "climate data record" (CDR) for global aerosol, determining whether the product has sufficient length, consistency and continuity to determine climate variability and change

  16. Study and Preliminary Analysis of Test of Aerosol Migration Mechanism

    Institute of Scientific and Technical Information of China (English)

    CHEN; Lin-lin; SUN; Xue-ting; WEI; Yan-song

    2015-01-01

    TAMM(test of aerosol migration mechanism)is one of the important aspects of Studies on Migration Mechanism of the Source Term under Severe Accident,which is a significant research of the National Large Advanced PWR Research Program.The main task researches the

  17. Science Overview Document Indirect and Semi-Direct Aerosol Campaign (ISDAC) April 2008

    Energy Technology Data Exchange (ETDEWEB)

    SJ Ghan; B Schmid; JM Hubbe; CJ Flynn; A Laskin; AA Zelenyuk; DJ Czizco; CN Long; G McFarquhar; J Verlinde; J Harrington; JW Strapp; P Liu; A Korolev; A McDonald; M Wolde; A Fridlind; T Garrett; G Mace; G Kok; S Brooks; D Collins; D Lubin; P Lawson; M Dubey; C Mazzoleni; M Shupe; S Xie; DD Turner; Q Min; EJ Mlawer; D Mitchell

    2007-11-01

    The ARM Climate Research Facility’s (ACRF) Aerial Vehicle Program (AVP) will deploy an intensive cloud and aerosol observing system to the ARM North Slope of Alaska (NSA) locale for a five week Indirect and Semi-Direct Aerosol Campaign (ISDAC) during period 29 March through 30 April 2008. The deployment period is within the International Polar Year, thus contributing to and benefiting from the many ancillary observing systems collecting data synergistically. We will deploy the Canadian National Research Council Convair 580 aircraft to measure temperature, humidity, total particle number, aerosol size distribution, single particle composition, concentrations of cloud condensation nuclei and ice nuclei, optical scattering and absorption, updraft velocity, cloud liquid water and ice contents, cloud droplet and crystal size distributions, cloud particle shape, and cloud extinction. In addition to these aircraft measurements, ISDAC will deploy two instruments at the ARM site in Barrow: a spectroradiometer to retrieve cloud optical depth and effective radius, and a tandem differential mobility analyzer to measure the aerosol size distribution and hygroscopicity. By using many of the same instruments used during Mixed-Phase Arctic Cloud Experiment (M-PACE), conducted in October 2004, we will be able to contrast the arctic aerosol and cloud properties during the fall and spring transitions. The aerosol measurements can be used in cloud models driven by objectively analyzed boundary conditions to test whether the cloud models can simulate the aerosol influence on the clouds. The influence of aerosol and boundary conditions on the simulated clouds can be separated by running the cloud models with all four combinations of M-PACE and ISDAC aerosol and boundary conditions: M-PACE aerosol and boundary conditions, M-PACE aerosol and ISDAC boundary conditions, ISDAC aerosol and M-PACE boundary conditions, and ISDAC aerosol and boundary conditions. ISDAC and M-PACE boundary

  18. Cloud Condensation Nuclei Activity of Aerosols during GoAmazon 2014/15 Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Martin, S. T. [Harvard Univ., Cambridge, MA (United States); Kleinman, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Thalman, R. M. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-01

    Aerosol indirect effects, which represent the impact of aerosols on climate through influencing the properties of clouds, remain one of the main uncertainties in climate predictions (Stocker et al. 2013). Reducing this large uncertainty requires both improved understanding and representation of aerosol properties and processes in climate models, including the cloud activation properties of aerosols. The Atmospheric System Research (ASR) science program plan of January 2010 states that: “A key requirement for simulating aerosol-cloud interactions is the ability to calculate cloud condensation nuclei and ice nuclei (CCN and IN, respectively) concentrations as a function of supersaturation from the chemical and microphysical properties of the aerosol.” The Observations and Modeling of the Green Ocean Amazon (GoAmazon 2014/15) study seeks to understand how aerosol and cloud life cycles are influenced by pollutant outflow from a tropical megacity (Manaus)—in particular, the differences in cloud-aerosol-precipitation interactions between polluted and pristine conditions. One key question of GoAmazon2014/5 is: “What is the influence of the Manaus pollution plume on the cloud condensation nuclei (CCN) activities of the aerosol particles and the secondary organic material in the particles?” To address this question, we measured size-resolved CCN spectra, a critical measurement for GoAmazon2014/5.

  19. CART and GSFC raman lidar measurements of atmospheric aerosol backscattering and extinction profiles for EOS validation and ARM radiation studies

    Science.gov (United States)

    Ferrare, R. A.; Turner, D. D.; Melfi, S. H.; Whiteman, D. N.; Schwenner, G.; Evans, K. D.; Goldsmith, J. E. M.; Tooman, T.

    1998-01-01

    The aerosol retrieval algorithms used by the Moderate-Resolution Imaging Spectroradiometer (MODIS) and Multi-Angle Imaging SpectroRadiometer (MISR) sensors on the Earth Observing Satellite (EOS) AM-1 platform operate by comparing measured radiances with tabulated radiances that have been computed for specific aerosol models. These aerosol models are based almost entirely on surface and/or column averaged measurements and so may not accurately represent the ambient aerosol properties. Therefore, to validate these EOS algorithms and to determine the effects of aerosols on the clear-sky radiative flux, we have begun to evaluate the vertical variability of ambient aerosol properties using the aerosol backscattering and extinction profiles measured by the Cloud and Radiation Testbed (CART) and NASA Goddard Space Flight Center (GSFC) Raman Lidars. Using the procedures developed for the GSFC Scanning Raman Lidar (SRL), we have developed and have begun to implement algorithms for the CART Raman Lidar to routinely provide profiles of aerosol extinction and backscattering during both nighttime and ,daytime operations. Aerosol backscattering and extinction profiles are computed for both lidar systems using data acquired during the 1996 and 1997 Water Vapor Intensive Operating Periods (IOPs). By integrating these aerosol extinction profiles, we derive measurements of aerosol optical thickness and compare these with coincident sun photometer measurements. We also use these measurements to measure the aerosol extinction/backscatter ratio S(sub a) (i.e. 'lidar ratio'). Furthermore, we use the simultaneous water vapor measurements acquired by these Raman lidars to investigate the effects of water vapor on aerosol optical properties.

  20. Aerosol dynamics in porous media

    NARCIS (Netherlands)

    Ghazaryan, Lilya

    2014-01-01

    In this thesis, a computational model was developed for the simulation of aerosol formation through nucleation, followed by condensation and evaporation and filtration by porous material. Understanding aerosol dynamics in porous media can help improving engineering models that are used in various in

  1. Testing of an automated online EA-IRMS method for fast and simultaneous carbon content and stable isotope measurement of aerosol samples

    Science.gov (United States)

    Major, István; Gyökös, Brigitta; Túri, Marianna; Futó, István; Filep, Ágnes; Hoffer, András; Molnár, Mihály

    2016-04-01

    Comprehensive atmospheric studies have demonstrated that carbonaceous aerosol is one of the main components of atmospheric particulate matter over Europe. Various methods, considering optical or thermal properties, have been developed for quantification of the accurate amount of both organic and elemental carbon constituents of atmospheric aerosol. The aim of our work was to develop an alternative fast and easy method for determination of the total carbon content of individual aerosol samples collected on prebaked quartz filters whereby the mass and surface concentration becomes simply computable. We applied the conventional "elemental analyzer (EA) coupled online with an isotope ratio mass spectrometer (IRMS)" technique which is ubiquitously used in mass spectrometry. Using this technique we are able to measure simultaneously the carbon stable isotope ratio of the samples, as well. During the developing process, we compared the EA-IRMS technique with an off-line catalytic combustion method worked out previously at Hertelendi Laboratory of Environmental Studies (HEKAL). We tested the combined online total carbon content and stable isotope ratio measurement both on standard materials and real aerosol samples. Regarding the test results the novel method assures, on the one hand, at least 95% of carbon recovery yield in a broad total carbon mass range (between 100 and 3000 ug) and, on the other hand, a good reproducibility of stable isotope measurements with an uncertainty of ± 0.2 per mill. Comparing the total carbon results obtained by the EA-IRMS and the off-line catalytic combustion method we found a very good correlation (R2=0.94) that proves the applicability of both preparation method. Advantages of the novel method are the fast and simplified sample preparation steps and the fully automated, simultaneous carbon stable isotope ratio measurement processes. Furthermore stable isotope ratio results can effectively be applied in the source apportionment

  2. Vertical distribution of aerosol number concentration in the troposphere over Siberia derived from airborne in-situ measurements

    Science.gov (United States)

    Arshinov, Mikhail Yu.; Belan, Boris D.; Paris, Jean-Daniel; Machida, Toshinobu; Kozlov, Alexandr; Malyskin, Sergei; Simonenkov, Denis; Davydov, Denis; Fofonov, Alexandr

    2016-04-01

    Knowledge of the vertical distribution of aerosols particles is very important when estimating aerosol radiative effects. To date there are a lot of research programs aimed to study aerosol vertical distribution, but only a few ones exist in such insufficiently explored region as Siberia. Monthly research flights and several extensive airborne campaigns carried out in recent years in Siberian troposphere allowed the vertical distribution of aerosol number concentration to be summarized. In-situ aerosol measurements were performed in a wide range of particle sizes by means of improved version of the Novosibirsk-type diffusional particle sizer and GRIMM aerosol spectrometer Model 1.109. The data on aerosol vertical distribution enabled input parameters for the empirical equation of Jaenicke (1993) to be derived for Siberian troposphere up to 7 km. Vertical distributions of aerosol number concentration in different size ranges averaged for the main seasons of the year will be presented. This work was supported by Interdisciplinary integration projects of the Siberian Branch of the Russian Academy of Science No. 35, No. 70 and No. 131; the Branch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5); and Russian Foundation for Basic Research (grant No. 14-05-00526). Jaenicke R. Tropospheric aerosols, in Aerosol-Cloud-Climate Interactions, edited by P.V. Hobs. -Academic Press, San Diego, CA, 1993.- P. 1-31.

  3. Aerosols indirectly warm the Arctic

    Directory of Open Access Journals (Sweden)

    T. Mauritsen

    2010-07-01

    Full Text Available On average, airborne aerosol particles cool the Earth's surface directly by absorbing and scattering sunlight and indirectly by influencing cloud reflectivity, life time, thickness or extent. Here we show that over the central Arctic Ocean, where there is frequently a lack of aerosol particles upon which clouds may form, a small increase in aerosol loading may enhance cloudiness thereby likely causing a climatologically significant warming at the ice-covered Arctic surface. Under these low concentration conditions cloud droplets grow to drizzle sizes and fall, even in the absence of collisions and coalescence, thereby diminishing cloud water. Evidence from a case study suggests that interactions between aerosol, clouds and precipitation could be responsible for attaining the observed low aerosol concentrations.

  4. An Indigenously Developed Insecticidal Aerosol

    Directory of Open Access Journals (Sweden)

    R. N. Varma

    1969-10-01

    Full Text Available A total of 6 "Test" insecticidal aerosols (TA-I to VI indigenously produced were tested during the years 1966-67 as suitable replacements for imported aerosols.TA-I produced deep yellow staining and a yellowish spray mist. Its capacity was only 120 ml fluid. TA-III types II and III containing modified aerosol formulation with "Esso solvent 3245" and mineral turpentine oil (Burmah Shelland Freon 12 11 (all indigenouswere comparable to he "SRA" in insecticidial efficacy. The container was also manufactured in the country and it compared well with the "SRA" in construction, resistance against rough usage and mechanical function. They were both finally approved for introduction in the services as replacement for imported aerosols. TA-IV performed well in inscticidial assessment, but the aerosols formulation. TA-V and VI were similar to TA-III types II and III respectively.

  5. Second-generation aerosol shock tube: an improved design

    Science.gov (United States)

    Haylett, D. R.; Davidson, D. F.; Hanson, R. K.

    2012-11-01

    An improved, second-generation aerosol shock tube (AST II) has been developed for the study of the chemical kinetics of low-vapor-pressure fuels. These improvements enable a wider range of fuel concentrations and enhanced spatial uniformity relative to our initial aerosol shock tube (AST I). In addition, the design of AST II limits the aerosol loading zone in the shock tube to a fixed region (1.2 m in length adjacent to the shock tube endwall). AST II achieves these improvements using a separate holding tank to prepare the aerosol mixture and a slightly under-pressure dump tank to carefully pull the aerosol mixture into the tube in a plug-flow. This filling method is capable of producing room temperature test gas mixtures of n-dodecane with equivalence ratios of up to 3.0 in 21 % O2, three times the loading achievable in the earlier AST I that used a flow-through strategy. Improvements in aerosol uniformity were quantified by measuring the liquid volume concentration at multiple locations in the shock tube. The measurements made over a length of 1.1 m of shock tube indicate that the AST II method of filling produces non-uniformities in liquid volume concentration of less than 2 %, whereas in the AST I method of filling the non-uniformities reached 16 %. The improved uniformity can also be seen in measurement of gas-phase fuel concentration behind the incident shock wave after the liquid droplets have evaporated. Significant reduction in the scatter of ignition delay times measured using AST II have also been achieved, confirming the importance of uniform loading of the aerosol in making high-quality combustion measurements.

  6. Aerosol characteristics at a remote island: Minicoy in southern Arabian Sea

    Indian Academy of Sciences (India)

    V Vinoj; S K Satheesh; K Krishna Moorthy

    2008-07-01

    Extensive measurements of aerosol optical and microphysical properties made at a remote island, Minicoy in southern Arabian Sea for the period (February 2006–March 2007) are used to characterize their temporal variability and Black Carbon (BC) mass mixing ratio. Large decrease in aerosol BC (from ∼800 ng m−3 to ∼100 ng m−3) was observed associated with change in airmass characteristics and monsoon rains. The total aerosol mass varied between ∼80 and 20 g m−3. Though the total mass fell drastically, a slight increase in super micron mass was observed during the June–August period associated with high winds. The mass fraction of Black Carbon aerosols during the prevalence of continental airmass is found to be ∼1.2% of the composite aerosols, which is much lower than the values reported earlier for this region.

  7. Characterization of carbonaceous aerosols during the MINOS campaign in Crete, July–August 2001: a multi-analytical approach

    Directory of Open Access Journals (Sweden)

    J. Sciare

    2003-01-01

    Full Text Available During the major part of the Mediterranean Intensive Oxidant Study (MINOS campaign (summer 2001, Crete Isl., the Marine Boundary Layer (MBL air was influenced by long range transport of biomass burning from the northern and western part of the Black Sea. During this campaign, carbonaceous aerosols were collected on quartz filters at a Free Tropospheric (FT site, and at a MBL site together with size-resolved distribution of aerosols. Three Evolution Gas Analysis (EGA protocols have been tested in order to better characterize the collected aged biomass burning smoke: A 2-step thermal method (Cachier et al., 1989 and a thermo-optical technique using two different temperature programs. The later temperature programs are those used for IMPROVE (Interagency Monitoring of Protected Visual Environments and NIOSH 5040 (National Institute of Occupational Safety and Health. Artifacts were observed using the NIOSH temperature program and identified as interactions between carbon and dust deposited on the filter matrix at high temperature (T>550ºC under the pure helium step of the analysis. During the MINOS campaign, Black Carbon (BC and Organic Carbon (OC mass concentrations were on average respectively 1.19±0.56 and 3.62±1.08 mgC/m3 for the IMPROVE temperature program, and 1.09±0.36 and 3.75±1.24 mgC/m3 for the thermal method. Though these values compare well on average and the agreement between the Total Carbon (TC measurements sample to sample was excellent (slope=1.00, r2=0.93, n=56, important discrepancies were observed in determining BC concentrations from these two methods (average error of 33±22%. BC from the IMPROVE temperature program compared well with non-sea-salt potassium (nss-K pointing out an optical sensitivity to biomass burning. On the other hand, BC from the thermal method showed a better agreement with non-sea-salt sulfate (nss-SO4, considered as a tracer for fossil fuel combustion during the MINOS campaign. The coupling between

  8. Characterization of carbonaceous aerosols during the MINOS campaign in Crete, July–August 2001: a multi-analytical approach

    Directory of Open Access Journals (Sweden)

    R. Sarda-Estève

    2003-07-01

    Full Text Available During the major part of the Mediterranean Intensive Oxidant Study (MINOS campaign (summer 2001, Crete Isl., the Marine Boundary Layer (MBL air was influenced by long range transport of biomass burning from the northern and western part of the Black Sea. During this campaign, carbonaceous aerosols were collected on quartz filters at a Free Tropospheric (FT site, and at a MBL site together with size-resolved distribution of aerosols. Three Evolution Gas Analysis (EGA protocols have been tested in order to better characterize the collected aged biomass burning smoke: A 2-step thermal method (Cachier et al., 1989 and a thermo-optical technique using two different temperature programs. The later temperature programs are those used for IMPROVE (Interagency Monitoring of Protected Visual Environments and NIOSH 5040 (National Institute of Occupational Safety and Health. Artifacts were observed using the NIOSH temperature program and identified as interactions between carbon and dust deposited on the filter matrix at high temperature (T=550°C under the pure helium step of the analysis. During the MINOS campaign, Black Carbon (BC and Organic Carbon (OC concentrations were on average respectively 1.19±0.56 and 3.62±1.08 μgC/m3 for the IMPROVE temperature program, and 1.09±0.36 and 3.75±1.24 μgC/m3 for the thermal method. Though these values compare well on average and the agreement between the Total Carbon (TC measurements sample to sample was excellent (slope = 1.00, r2=0.93, n=56, important discrepancies were observed in determining BC concentrations from these two methods (average error of 33±22%. BC from the IMPROVE temperature program compared well with non-sea-salt potassium (nss-K pointing out an optical sensitivity to biomass burning. On the other hand, BC from the thermal method showed a better agreement with non-sea-salt sulfate (nss-SO4, considered as a tracer for fossil fuel combustion during the MINOS campaign. The coupling

  9. Characterization of carbonaceous aerosols during the MINOS campaign in Crete, July-August 2001: a multi-analytical approach

    Science.gov (United States)

    Sciare, J.; Cachier, H.; Oikonomou, K.; Ausset, P.; Sarda-Estève, R.; Mihalopoulos, N.

    2003-07-01

    During the major part of the Mediterranean Intensive Oxidant Study (MINOS) campaign (summer 2001, Crete Isl.), the Marine Boundary Layer (MBL) air was influenced by long range transport of biomass burning from the northern and western part of the Black Sea. During this campaign, carbonaceous aerosols were collected on quartz filters at a Free Tropospheric (FT) site, and at a MBL site together with size-resolved distribution of aerosols. Three Evolution Gas Analysis (EGA) protocols have been tested in order to better characterize the collected aged biomass burning smoke: A 2-step thermal method (Cachier et al., 1989) and a thermo-optical technique using two different temperature programs. The later temperature programs are those used for IMPROVE (Interagency Monitoring of Protected Visual Environments) and NIOSH 5040 (National Institute of Occupational Safety and Health). Artifacts were observed using the NIOSH temperature program and identified as interactions between carbon and dust deposited on the filter matrix at high temperature (T=550°C) under the pure helium step of the analysis. During the MINOS campaign, Black Carbon (BC) and Organic Carbon (OC) concentrations were on average respectively 1.19±0.56 and 3.62±1.08 μgC/m3 for the IMPROVE temperature program, and 1.09±0.36 and 3.75±1.24 μgC/m3 for the thermal method. Though these values compare well on average and the agreement between the Total Carbon (TC) measurements sample to sample was excellent (slope = 1.00, r2=0.93, n=56), important discrepancies were observed in determining BC concentrations from these two methods (average error of 33±22%). BC from the IMPROVE temperature program compared well with non-sea-salt potassium (nss-K) pointing out an optical sensitivity to biomass burning. On the other hand, BC from the thermal method showed a better agreement with non-sea-salt sulfate (nss-SO4), considered as a tracer for fossil fuel combustion during the MINOS campaign. The coupling between

  10. Characterization of carbonaceous aerosols during the MINOS campaign in Crete, July August 2001: a multi-analytical approach

    Science.gov (United States)

    Sciare, J.; Cachier, H.; Oikonomou, K.; Ausset, P.; Sarda-Estève, R.; Mihalopoulos, N.

    2003-10-01

    During the major part of the Mediterranean Intensive Oxidant Study (MINOS) campaign (summer 2001, Crete Isl.), the Marine Boundary Layer (MBL) air was influenced by long range transport of biomass burning from the northern and western part of the Black Sea. During this campaign, carbonaceous aerosols were collected on quartz filters at a Free Tropospheric (FT) site, and at a MBL site together with size-resolved distribution of aerosols. Three Evolution Gas Analysis (EGA) protocols have been tested in order to better characterize the collected aged biomass burning smoke: A 2-step thermal method (Cachier et al., 1989) and a thermo-optical technique using two different temperature programs. The later temperature programs are those used for IMPROVE (Interagency Monitoring of Protected Visual Environments) and NIOSH 5040 (National Institute of Occupational Safety and Health). Artifacts were observed using the NIOSH temperature program and identified as interactions between carbon and dust deposited on the filter matrix at high temperature (T>550ºC) under the pure helium step of the analysis. During the MINOS campaign, Black Carbon (BC) and Organic Carbon (OC) mass concentrations were on average respectively 1.19±0.56 and 3.62±1.08 mgC/m3 for the IMPROVE temperature program, and 1.09±0.36 and 3.75±1.24 mgC/m3 for the thermal method. Though these values compare well on average and the agreement between the Total Carbon (TC) measurements sample to sample was excellent (slope=1.00, r2=0.93, n=56), important discrepancies were observed in determining BC concentrations from these two methods (average error of 33±22%). BC from the IMPROVE temperature program compared well with non-sea-salt potassium (nss-K) pointing out an optical sensitivity to biomass burning. On the other hand, BC from the thermal method showed a better agreement with non-sea-salt sulfate (nss-SO4), considered as a tracer for fossil fuel combustion during the MINOS campaign. The coupling between these

  11. Atmospheric and aerosol chemistry

    Energy Technology Data Exchange (ETDEWEB)

    McNeill, V. Faye [Columbia Univ., New York, NY (United States). Dept. of Chemical Engineering; Ariya, Parisa A. (ed.) [McGill Univ. Montreal, QC (Canada). Dept. of Chemistry; McGill Univ. Montreal, QC (Canada). Dept. of Atmospheric and Oceanic Sciences

    2014-09-01

    This series presents critical reviews of the present position and future trends in modern chemical research. Short and concise reports on chemistry, each written by the world renowned experts. Still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com. Christian George, Barbara D'Anna, Hartmut Herrmann, Christian Weller, Veronica Vaida, D. J. Donaldson, Thorsten Bartels-Rausch, Markus Ammann Emerging Areas in Atmospheric Photochemistry. Lisa Whalley, Daniel Stone, Dwayne Heard New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Neil M. Donahue, Allen L. Robinson, Erica R. Trump, Ilona Riipinen, Jesse H. Kroll Volatility and Aging of Atmospheric Organic Aerosol. P. A. Ariya, G. Kos, R. Mortazavi, E. D. Hudson, V. Kanthasamy, N. Eltouny, J. Sun, C. Wilde Bio-Organic Materials in the Atmosphere and Snow: Measurement and Characterization V. Faye McNeill, Neha Sareen, Allison N. Schwier Surface-Active Organics in Atmospheric Aerosols.

  12. International Cooperative for Aerosol Prediction Workshop on Aerosol Forecast Verification

    Science.gov (United States)

    Benedetti, Angela; Reid, Jeffrey S.; Colarco, Peter R.

    2011-01-01

    The purpose of this workshop was to reinforce the working partnership between centers who are actively involved in global aerosol forecasting, and to discuss issues related to forecast verification. Participants included representatives from operational centers with global aerosol forecasting requirements, a panel of experts on Numerical Weather Prediction and Air Quality forecast verification, data providers, and several observers from the research community. The presentations centered on a review of current NWP and AQ practices with subsequent discussion focused on the challenges in defining appropriate verification measures for the next generation of aerosol forecast systems.

  13. Measurement of contemporary and fossil carbon contents of PM 2.5 aerosols: results from Turtleback Dome, Yosemite National Park

    Energy Technology Data Exchange (ETDEWEB)

    Bench, G

    2003-10-17

    The impact of aerosol particulate matter of mean mass aerodynamic diameter {le} 2.5 {proportional_to}m (PM 2.5 aerosols), on health, visibility, and compliance with EPA's regional haze regulations is a growing concern. Techniques that can help better characterize particulate matter are required to better understand the constituents, causes and sources of PM 2.5 aerosols. Measurement of the {sup 14}C/C ratio of the PM 2.5 aerosols, the absence of {sup 14}C in fossil carbon materials and the known {sup 14}C/C levels in contemporary carbon materials allows use of a two-component model to derive contemporary and fossil carbon contents of the particulate matter. Such data can be used to estimate the relative contributions of fossil fuels and biogenic aerosols to the total aerosol loading. Here, the methodology for performing such an assessment using total suspended particulate Hi-vol aerosol samplers to collect PM 2.5 aerosols on quartz fiber filters and the technique of accelerator mass spectrometry to measure {sup 14}C/C ratios is presented and illustrated using PM 2.5 aerosols collected at Yosemite National Park.

  14. Lidar Observations of Arctic Aerosols and Clouds in the Free Troposphere for More than Fifteen Months over Svalbard

    Science.gov (United States)

    Shibata, T.; Shiraishi, K.; Iwasaki, S.; Shiobara, M.; Takano, T.

    2015-12-01

    The information on spatial distributions and microphysical properties of aerosols and clouds is crucial for the studies on their direct and indirect impacts on Arctic climate. Observations of tropospheric aerosols and clouds by Mie/depolarization lidar have been made for more than a year at Ny-Ålesund (79◌N, 12◌E) since March 2014 by using a pulsed Nd:YAG laser and its wavelengths of 1064 nm and 532 nm. The backscattering coefficients at these two wavelengths, and depolarization ratio at 532nm of aerosols and clouds are obtained by the lidar observations. Figures show the results of aerosols for more than a year. Fig. 1 shows the mean backscattering coefficient of aerosols (BSC) at 532 nm, and Fig. 2 shows mean particle depolarization ratio of aerosols (PDR) at 532 nm in 1 km intervals (0.4 km for the lowest height interval) to 5 km in altitude since March 2014 to May 2015. There is a maximum in backscattering coefficient at spring as indicated by previous studies on Arctic aerosols. In addition, there is another maximum at autumn in depolarization ratio and in color ratio, or the ratio of BSC at 1064 nm to BSC at 532 nm.

  15. Characterizing the formation of secondary organic aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Lunden, Melissa; Black, Douglas; Brown, Nancy

    2004-02-01

    Organic aerosol is an important fraction of the fine particulate matter present in the atmosphere. This organic aerosol comes from a variety of sources; primary organic aerosol emitted directly from combustion process, and secondary aerosol formed in the atmosphere from condensable vapors. This secondary organic aerosol (SOA) can result from both anthropogenic and biogenic sources. In rural areas of the United States, organic aerosols can be a significant part of the aerosol load in the atmosphere. However, the extent to which gas-phase biogenic emissions contribute to this organic load is poorly understood. Such an understanding is crucial to properly apportion the effect of anthropogenic emissions in these rural areas that are sometimes dominated by biogenic sources. To help gain insight on the effect of biogenic emissions on particle concentrations in rural areas, we have been conducting a field measurement program at the University of California Blodgett Forest Research Facility. The field location includes has been used to acquire an extensive suite of measurements resulting in a rich data set, containing a combination of aerosol, organic, and nitrogenous species concentration and meteorological data with a long time record. The field location was established in 1997 by Allen Goldstein, a professor in the Department of Environmental Science, Policy and Management at the University of California at Berkeley to study interactions between the biosphere and the atmosphere. The Goldstein group focuses on measurements of concentrations and whole ecosystem biosphere-atmosphere fluxes for volatile organic compounds (VOC's), oxygenated volatile organic compounds (OVOC's), ozone, carbon dioxide, water vapor, and energy. Another important collaborator at the Blodgett field location is Ronald Cohen, a professor in the Chemistry Department at the University of California at Berkeley. At the Blodgett field location, his group his group performs measurements of the

  16. Aerosol optical properties retrieved from Sun photometer measurements over Shanghai, China

    Science.gov (United States)

    He, Qianshan; Li, Chengcai; Geng, Fuhai; Yang, Hequn; Li, Peiren; Li, Tingting; Liu, Dongwei; Pei, Zhen

    2012-08-01

    Using a CIMEL Sun photometer, we conducted continuous observations over the urban area of Shanghai (31°14'N, 121°32'E) from 18 April 2007 to 31 January 2009. The aerosol optical depth (AOD), Angstrom wavelength exponent, single scattering albedo (ω0), and aerosol particle size distribution were derived from the observational data. The monthly mean AOD reached a maximum value of 1.20 in June and a minimum value of 0.43 in January. The monthly averaged Angstrom wavelength exponent reached a minimum value of 1.15 in April and a maximum value of 1.41 in October. The frequencies of the AOD and Angstrom wavelength exponent presented lognormal distributions. The averaged ω0 at 550 nm was 0.94 throughout the observation period, indicating that the aerosols over Shanghai are composed mainly of scattering particles. The concentrations of coarse mode and accumulation mode aerosols over Shanghai were highest in spring compared with other seasons, especially for those particles with radii between 1.0 and 2.0 μm. The median radius of monthly averaged accumulation mode aerosols increased with increasing AOD, and fine particles accounted for the majority of the aerosol volume concentration. The ratios of the monthly averaged volume concentration of accumulation mode and coarse mode aerosols (Vf/Vc) were over 0.6 for all months studied and reached up to 1.94 in August. The volumes of the two modes changed with AOD, but their correlations presented different sensitivities, that is, the volume concentration of accumulation mode aerosols was more sensitive to variations in AOD than that of coarse mode aerosols. The aerosol volume concentration decreased with increasing ω0, indicating that the higher the volume concentration of aerosols, the higher the absorption in particle extinction properties. The increase in absorption was caused primarily by secondary species coated on black carbon (BC) and primary organic carbon (POC) particles.

  17. Measurement of contemporary and fossil carbon contents of PM2.5 aerosols: results from Turtleback Dome, Yosemite National Park.

    Science.gov (United States)

    Bench, Graham

    2004-04-15

    The impact of aerosol particulate matter of mean mass aerodynamic diameter carbon materials, and the known 14C/C levels in contemporary carbon materials allow the use of a two-component model to derive contemporary and fossil carbon contents of the particulate matter. Such data can be used to estimate the relative contributions of fossil fuels and biogenic aerosols to the total aerosol loading. Here, the methodology for performing such an assessment using total suspended particulate hi-vol aerosol samplers to collect PM2.5 aerosols on quartz fiber filters and the technique of accelerator mass spectrometry to measure 14C/C ratios is presented and illustrated using PM2.5 aerosols collected at Yosemite National Park.

  18. The GRAPE aerosol retrieval algorithm

    Directory of Open Access Journals (Sweden)

    G. E. Thomas

    2009-11-01

    Full Text Available The aerosol component of the Oxford-Rutherford Aerosol and Cloud (ORAC combined cloud and aerosol retrieval scheme is described and the theoretical performance of the algorithm is analysed. ORAC is an optimal estimation retrieval scheme for deriving cloud and aerosol properties from measurements made by imaging satellite radiometers and, when applied to cloud free radiances, provides estimates of aerosol optical depth at a wavelength of 550 nm, aerosol effective radius and surface reflectance at 550 nm. The aerosol retrieval component of ORAC has several incarnations – this paper addresses the version which operates in conjunction with the cloud retrieval component of ORAC (described by Watts et al., 1998, as applied in producing the Global Retrieval of ATSR Cloud Parameters and Evaluation (GRAPE data-set.

    The algorithm is described in detail and its performance examined. This includes a discussion of errors resulting from the formulation of the forward model, sensitivity of the retrieval to the measurements and a priori constraints, and errors resulting from assumptions made about the atmospheric/surface state.

  19. Evaluation and application of passive and active optical remote sensing methods for the measurement of atmospheric aerosol properties

    Energy Technology Data Exchange (ETDEWEB)

    Mielonen, T.

    2010-07-01

    assumptions and more realistic assumptions improve the retrieved parameters. However, other derived parameters, i.e. aerosol optical depth may deteriorate. In additio, the possibility to improve aerosol typing based on active spaceborne measurements by adding an additional parameter into the retrieval was studied. Unfortunately, the available parameter (color ratio) did not bring additional information into the retrieval. For the application part, remote sensed data was used in the estimation of particulate matter at the surface and in the analysis of seasonal profiles of vertical properties. The studies in this thesis show that optical remote sensing can give invaluable information on the properties of atmospheric aerosols. However, the retrieval of aerosol properties with undetermined information content is an extremely difficult task. Thus, the user should be aware of the uncertainties and the error sources in the retrieved parameters. (orig.)

  20. Evaluation of Hindcast Global and Regional Simulations of Aerosol Property Profiles during the Two Column Aerosol Project (TCAP)

    Science.gov (United States)

    Zhang, K.; Fast, J. D.; Berg, L. K.; Rasch, P. J.; Easter, R. C.; Wang, H.; Ma, P. L.; Chand, D.; Ferrare, R. A.; Flynn, C. J.; Hostetler, C. A.; Sedlacek, A. J., III; Shilling, J. E.; Tomlinson, J. M.; Zelenyuk, A.

    2014-12-01

    Although the aerosol life cycle and its interaction with clouds are explicitly represented in many modern climate models, predictions of vertical distributions in aerosol mass concentration, composition, size, and optical properties still have relatively large uncertainties that consequently affect estimates of aerosol radiative forcing. The region near the east coast of North America is one area where aerosol-climate models have a large diversity. Motivated by this problem, the Two-Column Aerosol Project (TCAP) supported by the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) program collected intensive field campaign measurements in July 2012 and Feb 2013 at a column over Cape Cod and a second column located ~200 km to the east over the ocean. DOE's ARM Aerial Facility G-1 aircraft collected in situ measurements of aerosol mass, composition, size, and optical properties. The aerosol mixing state was estimated based on measurements from a single particle mass spectrometer. TCAP was the first science mission for the NASA Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) spectrometer deployed on the G-1 and the second generation downward-looking High Spectral Resolution Lidar (HSRL-2) deployed on the NASA B-200 aircraft. On many days, the aircraft measurements show one or more aerosol layers in the free troposphere above the residual and marine boundary layers. In this study, we perform hindcast simulations with both the global model CAM5 and the regional model WRF-Chem, using either low- or high- temporal-resolution emission data over North America. In-situ and remote sensing data collected from TCAP are used to evaluate the model simulations. We will discuss the impact of a) individual sources (anthropogenic, biogenic, and biomass burning), b) model horizontal/vertical resolutions, and c) biases in simulated meteorological conditions on the simulated aerosol properties and the direct aerosol forcing. Particular attention will be given to

  1. Mediterranean aerosol typing by integrating three-wavelength lidar and sun photometer measurements.

    Science.gov (United States)

    Perrone, M R; Burlizzi, P

    2016-07-01

    Backscatter lidar measurements at 355, 532, and 1064 nm combined with aerosol optical thicknesses (AOTs) from sun photometer measurements collocated in space and time were used to retrieve the vertical profiles of intensive and extensive aerosol parameters. Then, the vertical profiles of the Ångström coefficients for different wavelength pairs (Å(λ1, λ2, z)), the color ratio (CR(z)), the fine mode fraction (η(z)) at 532 nm, and the fine modal radius (R f (z)), which represent aerosol characteristic properties independent from the aerosol load, were used for typing the aerosol over the Central Mediterranean. The ability of the Ångström coefficients to identify the main aerosol types affecting the Central Mediterranean with the support of the backward trajectory analysis was first demonstrated. Three main aerosol types, which were designed as continental-polluted (CP), marine-polluted (MP), and desert-polluted (DP), were identified. We found that both the variability range and the vertical profile structure of the tested aerosol intensive parameters varied with the aerosol type. The variability range and the altitude dependence of the aerosol extinction coefficients at 355, 532, and 1064 nm, respectively, also varied with the identified aerosol types even if they are extensive aerosol parameters. DP, MP, and CP aerosols were characterized by the Å(532, 1064 nm) mean values ± 1 standard deviation equal to 0.5 ± 0.2, 1.1 ± 0.2, 1.6 ± 0.2, respectively. η(%) mean values ± 1SD were equal to 50 ± 10, 73 ± 7, and 86 ± 6 for DP, MP, and CP aerosols, respectively. The R f and CR mean values ± 1SD were equal to 0.16 ± 0.05 μm and 1.3 ± 0.3, respectively, for DP aerosols; to 0.12 ± 0.03 μm and 1.8 ± 0.4, respectively, for MP aerosols; and to 0.11 ± 0.02 μm and 1.7 ± 0.4, respectively, for CP aerosols. CP and DP aerosols were on average responsible for greater AOT and LR values, but

  2. Atmospheric aerosol characterization during Saharan dust outbreaks at Naples EARLINET station

    Science.gov (United States)

    Pisani, Gianluca; Armenante, Mario; Boselli, Antonella; Frontoso, Maria Grazia; Spinelli, Nicola; Wang, Xuan

    2007-10-01

    The optical properties and the spatial distribution of the tropospheric aerosols over Naples under Saharan dust outbreaks conditions have been studied by means of lidar measurements performed between May 2000 and August 2003 in the frame of the EARLINET project. Climatological analysis of sand plume has been done by comparing normal and dust affected conditions. Results in terms of backscattering and extinction coefficient as well as their integrated quantities show that the aerosol load from the ground level up to 2 Km during Saharan dust transport events is almost the same of normal conditions. This is probably due to the relevant widespread of local aerosol sources, such as vehicular traffic, industrial activities, etc. Nevertheless, when sand outbreaks occur, the extinction to backscattering ratio, i.e. the lidar ratio, clearly shows that the aerosol type in the lowest atmospheric layer changes. Moreover, Saharan dust transport events strong increase both integrated backscatter and optical dept above 2 km.

  3. Modeling investigation of light-absorbing aerosols in the Amazon Basin during the wet season

    Science.gov (United States)

    Wang, Qiaoqiao; Saturno, Jorge; Chi, Xuguang; Walter, David; Lavric, Jost V.; Moran-Zuloaga, Daniel; Ditas, Florian; Pöhlker, Christopher; Brito, Joel; Carbone, Samara; Artaxo, Paulo; Andreae, Meinrat O.

    2016-11-01

    We use a global chemical transport model (GEOS-Chem) to interpret observed light-absorbing aerosols in Amazonia during the wet season. Observed aerosol properties, including black carbon (BC) concentration and light absorption, at the Amazon Tall Tower Observatory (ATTO) site in the central Amazon have relatively low background levels but frequently show high peaks during the study period of January-April 2014. With daily temporal resolution for open fire emissions and modified aerosol optical properties, our model successfully captures the observed variation in fine/coarse aerosol and BC concentrations as well as aerosol light absorption and its wavelength dependence over the Amazon Basin. The source attribution in the model indicates the important influence of open fire on the observed variances of aerosol concentrations and absorption, mainly from regional sources (northern South America) and from northern Africa. The contribution of open fires from these two regions is comparable, with the latter becoming more important in the late wet season. The analysis of correlation and enhancement ratios of BC versus CO suggests transport times of fossil fuel combustion in the southern part of the basin (AAE ˜ 1) but more open fire and dust influence in the northern part (AAE > 1.8). Uncertainty analysis shows that accounting for absorption due to secondary organic aerosol (SOA) and primary biogenic aerosol (PBA) particles could result in differences of < 8 and 5-40 % in total absorption, respectively.

  4. Secondary Organic Aerosol formation from the gas-phase reaction of catechol with ozone

    Science.gov (United States)

    Coeur-Tourneur, C.; Tomas, A.; Guilloteau, A.; Henry, F.; Ledoux, F.; Visez, N.; Riffault, V.; Wenger, J. C.; Bedjanian, Y.; Foulon, V.

    2009-04-01

    The formation of secondary organic aerosol from the gas-phase reaction of catechol (1,2-dihydroxybenzene) with ozone has been studied in two smog chambers (at the LPCA in France and at the CRAC in Ireland). Aerosol production was monitored using a scanning mobility particle sizer. The overall organic aerosol yield (Y) was determined as the ratio of the suspended aerosol mass corrected for wall losses (Mo) to the total reacted catechol concentrations, assuming a particle density of 1.4 g cm-3. Analysis of the data clearly shows that Y is a strong function of Mo and that secondary organic aerosol formation can be expressed by a one-product gas/particle partitioning absorption model. The aerosol formation is affected by the initial catechol concentration, which leads to aerosol yields ranging from 17% to 86%. The aerosol yields determined in the LPCA and CRAC smog chambers were comparable and were also in accordance with those determined in a previous study performed in EUPHORE (EUropean PHOto REactor, Spain).

  5. Parameterization of the Optical Properties of Sulfate Aerosols in the Infrared.

    Science.gov (United States)

    Li, J.; Min, Qilong

    2002-11-01

    Parameterizations of absorptance depth for ammonium sulfate [(NH4)2SO4], ammonium bisulfate (NH4HSO4), and sulfuric acid (H2SO4) in the infrared are provided for an eight-band model (covering 340-2500 cm1) and for 32 individual wavenumbers in order to generate other band schemes. The parameterization is simple in form and in its dependence on relative humidity.It is found that the aerosol surface infrared forcing can cancel about 12%-24% aerosol surface solar forcing in a clear sky condition. Also the existence of clouds could enhance the ratio of aerosol surface infrared forcing to the aerosol surface solar forcing. In contrast to the solar case, a small mode size distribution does not always produce a larger aerosol surface forcing. Also it is found that the aerosol surface forcing is dependent on the aerosol location. Very simple analysis is presented to help understand the related physics on sulfate aerosol infrared radiative forcing.

  6. eDPS Aerosol Collection

    Energy Technology Data Exchange (ETDEWEB)

    Venzie, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-13

    The eDPS Aerosol Collection project studies the fundamental physics of electrostatic aerosol collection for national security applications. The interpretation of aerosol data requires understanding and correcting for biases introduced from particle genesis through collection and analysis. The research and development undertaken in this project provides the basis for both the statistical correction of existing equipment and techniques; as well as, the development of new collectors and analytical techniques designed to minimize unwanted biases while improving the efficiency of locating and measuring individual particles of interest.

  7. Airborne measurements of aerosol optical properties related to early spring transport of mid-latitude sources into the Arctic

    Directory of Open Access Journals (Sweden)

    R. A. de Villiers

    2010-06-01

    Full Text Available Airborne lidar and in-situ measurements of the aerosol properties were conducted between Svalbard Island and Scandinavia in April 2008. Evidence of aerosol transport from Europe and Asia is given. The analysis of the aerosol optical properties based on a multiwavelength lidar (355, 532, 1064 nm including volume depolarization at 355 nm aims at distinguishing the role of the different aerosol sources (Siberian wild fires, Eastern Asia and European anthropogenic emissions. Combining, first aircraft measurements, second FLEXPART simulations with a calculation of the PBL air fraction originating from the three different mid-latitude source regions, and third level-2 CALIPSO data products (i.e. backscatter coefficient 532 nm,volume depolarization and color ratio between 1064 and 532 nm in aerosol layers along the transport pathways, appears a valuable approach to identify the role of the different aerosol sources even after a transport time larger than 4 days. Optical depth of the aerosol layers are always rather small (<4% while transported over the Arctic and ratio of the total attenuated backscatter (i.e. including molecular contribution provide more stable result than conventional aerosol backscatter ratio. Above Asia, CALIPSO data indicate more depolarization (up to 15% and largest color ratio (>0.5 for the northeastern Asia emissions (i.e. an expected mixture of Asian pollution and dust, while low depolarization together with smaller and quasi constant color ratio (≈0.3 are observed for the Siberian biomass burning emissions. A similar difference is visible between two layers observed by the aircraft above Scandinavia. The analysis of the time evolution of the aerosol optical properties revealed by CALIPSO between Asia and Scandinavia shows a gradual decrease of the aerosol backscatter, depolarization ratio and color ratio which suggests the removal of the largest particles in the accumulation mode. A similar study conducted for a European

  8. Aerosol quantification with the Aerodyne Aerosol Mass Spectrometer: detection limits and ionizer background effects

    Directory of Open Access Journals (Sweden)

    F. Drewnick

    2008-10-01

    Full Text Available Systematic laboratory experiments were performed to investigate quantification of various species with two versions of the Aerodyne Aerosol Mass Spectrometer, a Q-AMS and a c-ToF-AMS. Here we present a new method to continuously determine the detection limits of the AMS analyzers during regular measurements, yielding DL information under various measurement conditions. Minimum detection limits range from 0.03 μg m−3 (nitrate, sulfate, and chloride up to 0.5 μg m−3 (organics for the Q-AMS. Those of the c-ToF-AMS are found between 0.003 μg m−3 (nitrate, sulfate and 0.03 μg m−3 (ammonium, organics. The DL values found for the c-ToF-AMS were ~10 times lower than those of the Q-AMS, mainly due to differences in ion duty cycle. Effects causing an increase of the detection limits include long-term instrument contamination, measurement of high aerosol mass concentrations and short-term instrument history. The self-cleaning processes which reduce the instrument background after measurement of large aerosol concentrations as well as the influences of increased instrument background on mass concentration measurements are discussed. Finally, improvement of detection limits by extension of averaging time intervals, selected or reduced ion monitoring, and variation of particle-to-background measurement ratio are investigated.

  9. Photochemical processing of organic aerosol at nearby continental sites: contrast between urban plumes and regional aerosol

    Directory of Open Access Journals (Sweden)

    J. G. Slowik

    2010-10-01

    Full Text Available As part of the BAQS-Met 2007 field campaign, Aerodyne time-of-flight aerosol mass spectrometers (ToF-AMS were deployed at two sites in southwestern Ontario from 17 June to 11 July, 2007. One instrument was located at Harrow, ON, a rural, agriculture-dominated area approximately 40 km southeast of the Detroit/Windsor/Windsor urban area and 5 km north of Lake Erie. The second instrument was located at Bear Creek, ON, a rural site approximately 70 km northeast of the Harrow site and 50 km east of Detroit/Windsor. Positive matrix factorization analysis of the combined organic mass spectral dataset yields factors related to secondary organic aerosol (SOA, direct emissions, and uptake processes. This is the first application of PMF to simultaneous AMS measurements at different sites, an approach which allows for self-consistent, direct comparison of the datasets. Case studies are utilized to investigate processing of SOA from (1 fresh emissions from Detroit/Windsor and (2 regional aerosol during periods of inter-site flow. A strong correlation is observed between SOA/excess CO and photochemical age as represented by the NOx/NOy ratio for Detroit/Windsor outflow. Although this correlation is not evident for more aged air, measurements at the two sites during inter-site transport nevertheless show evidence of continued atmospheric processing by SOA production.

  10. Variability of aerosol optical properties in the Western Mediterranean Basin

    Science.gov (United States)

    Pandolfi, M.; Cusack, M.; Alastuey, A.; Querol, X.

    2011-08-01

    Aerosol light scattering, absorption and particulate matter (PM) concentrations were measured at Montseny, a regional background site in the Western Mediterranean Basin (WMB) which is part of the European Supersite for Atmospheric Aerosol Research (EUSAAR). Off line analyses of 24 h PM filters collected with Hi-Vol instruments were performed for the determination of the main chemical components of PM. Mean scattering and hemispheric backscattering coefficients (@ 635 nm) were 26.6±23.2 Mm-1 and 4.3±2.7 Mm-1, respectively and the mean aerosol absorption coefficient (@ 637 nm) was 2.8±2.2 Mm-1. Mean values of Single Scattering Albedo (SSA) and Ångström exponent (å) (calculated from 450 nm to 635 nm) at MSY were 0.90±0.05 and 1.3±0.5 respectively. A clear relationship was observed between the PM1/PM10 and PM2.5/PM10 ratios as a function of the calculated Ångström exponents. Mass scattering cross sections (MSC) for fine mass and sulfate at 635 nm were 2.8±0.5 m2 g-1 and 11.8±2.2 m2 g-1, respectively, while the mean aerosol absorption cross section (MAC) was 10.4±2.0 m2 g-1. The variability in aerosol optical properties in the WMB were largely explained by the origin and ageing of air masses over the measurement site. The MAC values appear dependent of particles aging: similar to the expected absorption cross-section for fresh emissions under Atlantic Advection episodes and higher under aerosol pollution episodes. The analysis of the Ångström exponent as a function of the origin the air masses revealed that polluted winter anticyclonic conditions and summer recirculation scenarios typical of the WMB led to an increase of fine particles in the atmosphere (å = 1.5±0.1) while the aerosol optical properties under Atlantic Advection episodes and Saharan dust outbreaks were clearly dominated by coarser particles (å = 1.0±0.4). The sea breeze played an important role in transporting pollutants from the developed WMB coastlines towards inland rural areas

  11. Stratospheric aerosol geoengineering

    Science.gov (United States)

    Robock, Alan

    2015-03-01

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

  12. Aerosol Transmission of Filoviruses

    Directory of Open Access Journals (Sweden)

    Berhanu Mekibib

    2016-05-01

    Full Text Available Filoviruses have become a worldwide public health concern because of their potential for introductions into non-endemic countries through international travel and the international transport of infected animals or animal products. Since it was first identified in 1976, in the Democratic Republic of Congo (formerly Zaire and Sudan, the 2013–2015 western African Ebola virus disease (EVD outbreak is the largest, both by number of cases and geographical extension, and deadliest, recorded so far in medical history. The source of ebolaviruses for human index case(s in most outbreaks is presumptively associated with handling of bush meat or contact with fruit bats. Transmission among humans occurs easily when a person comes in contact with contaminated body fluids of patients, but our understanding of other transmission routes is still fragmentary. This review deals with the controversial issue of aerosol transmission of filoviruses.

  13. Stratospheric aerosol geoengineering

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-30

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

  14. Aerosol single-scattering albedo and asymmetry parameter from MFRSR observations during the ARM Aerosol IOP 2003

    Directory of Open Access Journals (Sweden)

    E. I. Kassianov

    2007-06-01

    Full Text Available Multi-filter Rotating Shadowband Radiometers (MFRSRs provide routine measurements of the aerosol optical depth (τ at six wavelengths (0.415, 0.5, 0.615, 0.673, 0.870 and 0.94 μm. The single-scattering albedo (π0 is typically estimated from the MFRSR measurements by assuming the asymmetry parameter (g. In most instances, however, it is not easy to set an appropriate value of g due to its strong temporal and spatial variability. Here, we introduce and validate an updated version of our retrieval technique that allows one to estimate simultaneously π0 and g for different types of aerosol. We use the aerosol and radiative properties obtained during the Atmospheric Radiation Measurement (ARM Program's Aerosol Intensive Operational Period (IOP to validate our retrieval in two ways. First, the MFRSR-retrieved optical properties are compared with those obtained from independent surface, Aerosol Robotic Network (AERONET, and aircraft measurements. The MFRSR-retrieved optical properties are in reasonable agreement with these independent measurements. Second, we perform radiative closure experiments using the MFRSR-retrieved optical properties. The calculated broadband values of the direct and diffuse fluxes are comparable (~5 W/m2 to those obtained from measurements.

  15. Evaluation of synergized pyrethrin aerosol for control of Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae).

    Science.gov (United States)

    Kharel, Kabita; Arthur, Frank H; Zhu, Kun Yan; Campbell, James F; Subramanyam, Bhadriraju

    2014-02-01

    Aerosol insecticides are being used in flour mill pest management programs, but there is limited information on their efficacy on different insect life stages. In this study, we evaluated the efficacy of synergized pyrethrin applied as an aerosol against eggs, larvae, pupae, and adults of the red flour beetle, Tribolium castaneum (Herbst), and the confused flour beetle, Tribolium confusum Jacquelin du Val. Effects of direct and indirect exposure were evaluated by exposing each life stage to the aerosol and then transferring to untreated flour, transferring untreated insects to treated flour, or exposing both the insects and the flour to the aerosol. The aerosol produced >88% mortality of both species and all life stages when insects were directly treated and transferred to either treated or untreated flour. Mortality was significantly reduced when insects were either treated together with flour or untreated insects were transferred to treated flour (indirect exposure to the aerosol). Larvae and adults of both species were more tolerant compared with eggs and pupae. Recovery of moribund adults in the indirect exposure treatments was greater compared with recovery of moribund insects in the direct exposure treatments. Good sanitation before aerosol application could facilitate direct exposure of insects and thus increase aerosol efficacy inside flour mills.

  16. Do atmospheric aerosols form glasses?

    OpenAIRE

    Zobrist, B.; Marcolli, C.; Pedernera, D. A.; Koop, T.

    2008-01-01

    A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline) solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg

  17. The Joint Aerosol-Monsoon Experiment: A New Challenge to Monsoon Climate Research

    Science.gov (United States)

    Lau, William K. M.

    2008-01-01

    Aerosol and monsoon related droughts and floods are two of the most serious environmental hazards confronting more than 60% of the population of the world living in the Asian monsoon countries. In recent years, thanks to improved satellite and in-situ observations, and better models, great strides have been made in aerosol, and monsoon research respectively. There is now a growing body of evidence suggesting that interaction of aerosol forcing with water cycle dynamics in monsoon regions may substantially alter the redistribution of energy at the earth surface and in the atmosphere, and therefore significantly impact monsoon rainfall variability and long term trends. In this talk, I will describe issues related to societal needs, scientific background, and challenges in studies of aerosol-water cycle interaction in Asian monsoon regions. As a first step towards addressing these issues, the authors call for an integrated observation and modeling research approach aimed at the interactions between aerosol chemistry and radiative effects and monsoon dynamics of the coupled ocean-atmosphere-land system. A Joint Aerosol-Monsoon Experiment (JAMEX) is proposed for 2007-2011, with an enhanced observation period during 2008-09, encompassing diverse arrays of observations from surface, aircraft, unmanned aerial vehicles, and satellites of physical and chemical properties of aerosols, long range aerosol transport as well as meteorological and oceanographic parameters in the Indo-Pacific Asian monsoon region. JAMEX will leverage on coordination among many ongoing and planned national programs on aerosols and monsoon research in China, India, Japan, Nepal, Italy, US, as well as international research programs of the World Climate Research Program (WCRP) and the World Meteorological Organization (WMO).

  18. CALIPSO Observations of Aerosol Properties Near Clouds

    Science.gov (United States)

    Marshak, Alexander; Varnai, Tamas; Yang, Weidong

    2010-01-01

    Clouds are surrounded by a transition zone of rapidly changing aerosol properties. Characterizing this zone is important for better understanding aerosol-cloud interactions and aerosol radiative effects as well as for improving satellite measurements of aerosol properties. We present a statistical analysis of a global dataset of CALIPSO (Cloud-Aerosol Lidar and infrared Pathfinder Satellite Observation) Lidar observations over oceans. The results show that the transition zone extends as far as 15 km away from clouds and it is ubiquitous over all oceans. The use of only high confidence level cloud-aerosol discrimination (CAD) data confirms the findings. However, the results underline the need for caution to avoid biases in studies of satellite aerosol products, aerosol-cloud interactions, and aerosol direct radiative effects.

  19. Devices and methods for generating an aerosol

    KAUST Repository

    Bisetti, Fabrizio

    2016-03-03

    Aerosol generators and methods of generating aerosols are provided. The aerosol can be generated at a stagnation interface between a hot, wet stream and a cold, dry stream. The aerosol has the benefit that the properties of the aerosol can be precisely controlled. The stagnation interface can be generated, for example, by the opposed flow of the hot stream and the cold stream. The aerosol generator and the aerosol generation methods are capable of producing aerosols with precise particle sizes and a narrow size distribution. The properties of the aerosol can be controlled by controlling one or more of the stream temperatures, the saturation level of the hot stream, and the flow times of the streams.

  20. Chemistry of Atmospheric Aerosols at Pacifichem 2015 Congress

    Energy Technology Data Exchange (ETDEWEB)

    Nizkorodov, Sergey [Univ. of California, Irvine, CA (United States)

    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

  1. COS in the stratosphere. [sulfuric acid aerosol precursor

    Science.gov (United States)

    Inn, E. C. Y.; Vedder, J. F.; Tyson, B. J.; Ohara, D.

    1979-01-01

    Carbonyl sulfide (COS) has been detected in the stratosphere, and mixing ratio measurements are reported for altitudes of 15.2 to 31.2 km. A large volume, cryogenic sampling system mounted on board a U-2 aircraft has been used for lower stratosphere measurements and a balloon platform for measurement at 31.2 km. These observations and measurements strongly support the concept that stratospheric COS is an important precursor in the formation of sulfuric acid aerosols.

  2. Vertical Transport of Aerosol Particles across Mountain Topography near the Los Angeles Basin

    Science.gov (United States)

    Murray, J. J.; Schill, S.; Freeman, S.; Bertram, T. H.; Lefer, B. L.

    2015-12-01

    Transport of aerosol particles is known to affect air quality and is largely dependent on the characteristic topography of the surrounding region. To characterize this transport, aerosol number distributions were collected with an Ultra-High Sensitivity Aerosol Spectrometer (UHSAS, DMT) during the 2015 NASA Student Airborne Research Program (SARP) in and around the Los Angeles Basin in Southern California. Increases in particle number concentration and size were observed over mountainous terrain north of Los Angeles County. Chemical analysis and meteorological lagrangian trajectories suggest orographic lifting processes, known as the "chimney effect". Implications for spatial transport and distribution will be discussed.

  3. Tropospheric ozone and aerosols measured by airborne lidar during the 1988 Arctic boundary layer experiment

    Science.gov (United States)

    Browell, Edward V.; Butler, Carolyn F.; Kooi, Susan A.

    1991-01-01

    Ozone (O3) and aerosol distributions were measured from an aircraft using a differential absorption lidar (DIAL) system as part of the 1988 NASA Global Tropospheric Experiment - Arctic Boundary Layer Experiment (ABLE-3A) to study the sources and sinks of gases and aerosols over the tundra regions of Alaska during the summer. The tropospheric O3 budget over the Arctic was found to be strongly influenced by stratospheric intrusions. Regions of low aerosol scattering and enhanced O3 mixing ratios were usually correlated with descending air from the upper troposphere or lower stratosphere. Several cases of continental polar air masses were examined during the experiment. The aerosol scattering associated with these air masses was very low, and the atmospheric distribution of aerosols was quite homogeneous for those air masses that had been transported over the ice for greater than or = 3 days. The transition in O3 and aerosol distributions from tundra to marine conditions was examined several times. The aerosol data clearly show an abrupt change in aerosol scattering properties within the mixed layer from lower values over the tundra to generally higher values over the water. The distinct differences in the heights of the mixed layers in the two regions was also readily apparent. Several cases of enhanced O3 were observed during ABLE-3 in conjunction with enhanced aerosol scattering in layers in the free atmosphere. Examples are presented of the large scale variations of O3 and aerosols observed with the airborne lidar system from near the surface to above the tropopause over the Arctic during ABLE-3.

  4. Evaluation of biomass burning aerosols in the HadGEM3 climate model with observations from the SAMBBA field campaign

    Science.gov (United States)

    Johnson, Ben T.; Haywood, James M.; Langridge, Justin M.; Darbyshire, Eoghan; Morgan, William T.; Szpek, Kate; Brooke, Jennifer K.; Marenco, Franco; Coe, Hugh; Artaxo, Paulo; Longo, Karla M.; Mulcahy, Jane P.; Mann, Graham W.; Dalvi, Mohit; Bellouin, Nicolas

    2016-11-01

    We present observations of biomass burning aerosol from the South American Biomass Burning Analysis (SAMBBA) and other measurement campaigns, and use these to evaluate the representation of biomass burning aerosol properties and processes in a state-of-the-art climate model. The evaluation includes detailed comparisons with aircraft and ground data, along with remote sensing observations from MODIS and AERONET. We demonstrate several improvements to aerosol properties following the implementation of the Global Model for Aerosol Processes (GLOMAP-mode) modal aerosol scheme in the HadGEM3 climate model. This predicts the particle size distribution, composition, and optical properties, giving increased accuracy in the representation of aerosol properties and physical-chemical processes over the Coupled Large-scale Aerosol Scheme for Simulations in Climate Models (CLASSIC) bulk aerosol scheme previously used in HadGEM2. Although both models give similar regional distributions of carbonaceous aerosol mass and aerosol optical depth (AOD), GLOMAP-mode is better able to capture the observed size distribution, single scattering albedo, and Ångström exponent across different tropical biomass burning source regions. Both aerosol schemes overestimate the uptake of water compared to recent observations, CLASSIC more so than GLOMAP-mode, leading to a likely overestimation of aerosol scattering, AOD, and single scattering albedo at high relative humidity. Observed aerosol vertical distributions were well captured when biomass burning aerosol emissions were injected uniformly from the surface to 3 km. Finally, good agreement between observed and modelled AOD was gained only after scaling up GFED3 emissions by a factor of 1.6 for CLASSIC and 2.0 for GLOMAP-mode. We attribute this difference in scaling factor mainly to different assumptions for the water uptake and growth of aerosol mass during ageing via oxidation and condensation of organics. We also note that similar agreement

  5. Tropospheric Vertical Profiles of Aerosol Optical, Microphysical and Concentration Properties in the Frame of the Hygra-CD Campaign (Athens, Greece 2014: A Case Study of Long-Range Transport of Mixed Aerosols

    Directory of Open Access Journals (Sweden)

    Papayannis Alexandros

    2016-01-01

    Full Text Available Combined multi-wavelength aerosol Raman lidar and sun photometry measurements were performed during the HYGRA-CD campaign over Athens, Greece during May-June 2014. The retrieved aerosol optical properties (3 aerosol backscatter at 355-532-1064 nm and 2 aerosol extinction profiles at 355-532 nm were used as input to an inversion code to retrieve the aerosol microphysical properties (effective radius reff and number concentration N using regularization techniques. Additionally, the volume concentration profile was derived for fine particles using the LIRIC code. In this paper we selected a complex case study of long-range transport of mixed aerosols (biomass burning particles mixed with dust arriving over Athens between 10-12 June 2014 in the 1.5-4 km height. Between 2-3 km height we measured mean lidar ratios (LR ranging from 45 to 58 sr (at 355 and 532 nm, while the Ångström exponent (AE aerosol extinction-related values (355nm/532nm ranged between 0.8-1.3. The retrieved values of reff and N ranged from 0.19±0.07 to 0.22±0.07 μm and 460±230 to 2200±2800 cm-3, respectively. The aerosol linear depolarization ratio (δ at 532 nm was lower than 5-7% (except for the Saharan dust cases, where δ~10-15%.

  6. Aerosol Composition in the Los Angeles Basin Studied by High Resolution Aerosol Mass Spectrometry

    Science.gov (United States)

    Hayes, P. L.; Ortega, A. M.; Cubison, M.; Hu, W.; Toohey, D. W.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; Alvarez, S. L.; Rappenglueck, B.; Allan, J. D.; Taylor, J.; Holloway, J. S.; Gilman, J. B.; Kuster, W. C.; De Gouw, J. A.; Massoli, P.; Zhang, X.; Weber, R.; Zhao, Y.; Cliff, S. S.; Wexler, A. S.; Isaacman, G. A.; Worton, D. R.; Kreisberg, N. M.; Hering, S. V.; Goldstein, A. H.; Jimenez, J. L.

    2011-12-01

    Atmospheric aerosols impact climate and health, but their sources and composition are poorly understood. To address this knowledge gap, a high-resolution aerosol mass spectrometer (AMS) and complementary instrumentation were deployed during the 2010 CalNex campaign to characterize aerosol composition in the Los Angeles (LA) area. Total mass concentrations as well as the species concentrations measured by the AMS compare well with most other instruments. Nitrate dominates in the mornings, but its concentration is reduced in the afternoon when organic aerosols (OA) increase and dominate. The diurnal variations in concentrations are strongly influenced by emission transport from the source-rich western basin. The average OA to enhanced CO ratio increases with photochemical age from 25 to 80 μg m-3 ppm-1, which indicates significant secondary OA (SOA) production and that a large majority of OA is secondary in aged air. The ratio values are similar to those from Mexico City as well as New England and the Mid-Atlantic States. Positive matrix factorization (PMF) is used to assess the concentrations of different OA components. The major OA classes are oxygenated OA (OOA, a surrogate for total SOA), and hydrocarbon-like OA (HOA, a surrogate for primary combustion OA). Several subclasses of OA are identified as well including diesel-influenced HOA (DI-HOA) and non-diesel HOA. DI-HOA exhibits low concentrations on Sundays consistent with the well-known weekday/weekend effect in LA. PMF analysis finds that OOA is 67% of the total OA concentration. A strong correlation between OOA and Ox (O3 + NO2) concentrations is observed with a slope of 0.15 that suggests the production of fresh SOA in Pasadena. Plotting the OA elemental ratios in a Van Krevelen diagram (H:C vs. O:C) yields a slope of -0.6, which is less steep than that observed in Riverside during the SOAR-2005 campaign. The difference in slopes may be attributed to the highly oxidized HOA present in Pasadena that is

  7. Evaluation of Daytime Measurements of Aerosols and Water Vapor made by an Operational Raman Lidar over the Southern Great Plains

    Science.gov (United States)

    Ferrare, Richard; Turner, David; Clayton, Marian; Schmid, Beat; Covert, David; Elleman, Robert; Orgren, John; Andrews, Elisabeth; Goldsmith, John E. M.; Jonsson, Hafidi

    2006-01-01

    Raman lidar water vapor and aerosol extinction profiles acquired during the daytime over the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in northern Oklahoma (36.606 N, 97.50 W, 315 m) are evaluated using profiles measured by in situ and remote sensing instruments deployed during the May 2003 Aerosol Intensive Operations Period (IOP). The automated algorithms used to derive these profiles from the Raman lidar data were first modified to reduce the adverse effects associated with a general loss of sensitivity of the Raman lidar since early 2002. The Raman lidar water vapor measurements, which are calibrated to match precipitable water vapor (PWV) derived from coincident microwave radiometer (MWR) measurements were, on average, 5-10% (0.3-0.6 g/m(exp 3) higher than the other measurements. Some of this difference is due to out-of-date line parameters that were subsequently updated in the MWR PWV retrievals. The Raman lidar aerosol extinction measurements were, on average, about 0.03 km(exp -1) higher than aerosol measurements derived from airborne Sun photometer measurements of aerosol optical thickness and in situ measurements of aerosol scattering and absorption. This bias, which was about 50% of the mean aerosol extinction measured during this IOP, decreased to about 10% when aerosol extinction comparisons were restricted to aerosol extinction values larger than 0.15 km(exp -1). The lidar measurements of the aerosol extinction/backscatter ratio and airborne Sun photometer measurements of the aerosol optical thickness were used along with in situ measurements of the aerosol size distribution to retrieve estimates of the aerosol single scattering albedo (omega(sub o)) and the effective complex refractive index. Retrieved values of omega(sub o) ranged from (0.91-0.98) and were in generally good agreement with omega(sub o) derived from airborne in situ measurements of scattering and absorption. Elevated aerosol

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

    Science.gov (United States)

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

    2016-07-01

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

  9. The Finokalia Aerosol Measurement Experiment – 2008 (FAME-08: an overview

    Directory of Open Access Journals (Sweden)

    M. Pikridas

    2010-03-01

    Full Text Available A month (4 May to 8 June 2008 of ambient aerosol, air ion and gas phase sampling (Finokalia Aerosol Measurement Experiment 2008, FAME-08 was conducted at Finokalia, on the island of Crete, Greece. The purpose of the study was to characterize the physical and chemical properties of aged aerosol and to investigate new particle formation. Measurements included aerosol and air ion size distributions, size-resolved chemical composition, organic aerosol thermal volatility, water uptake and particle optical properties (light scattering and absorption. Statistical analysis of the aerosol mass concentration variations revealed the absence of diurnal patterns suggesting the lack of strong local sources. Sulfates accounted for approximately half of the particulate matter less than 1 micrometer in diameter (PM1 and organics for 26%. The PM1 organic aerosol fraction was highly oxidized with 80% water soluble. The supermicrometer particles were dominated by crustal components (50%, sea salt (24% and nitrates (16%. The organic carbon to elemental carbon (OC/EC ratio correlated with ozone measurements but with a one-day lag. The average OC/EC ratio for the study period was equal to 5.4. For three days air masses from North Africa resulted in a 6-fold increase of particulate matter less than 10 micrometers in diameter (PM10 and a decrease of the OC/EC ratio by a factor of 2. Back trajectory analysis, based on FLEXPART footprint plots, identified five source regions (Athens, Greece, Africa, other continental and marine, each of which influenced the PM1 aerosol composition and properties. Marine air masses had the lowest PM1 concentrations and air masses from the Balkans, Turkey and Eastern Europe the highest.

  10. The Finokalia Aerosol Measurement Experiment – 2008 (FAME-08: an overview

    Directory of Open Access Journals (Sweden)

    M. Pikridas

    2010-07-01

    Full Text Available A month (4 May to 8 June 2008 of ambient aerosol, air ion and gas phase sampling (Finokalia Aerosol Measurement Experiment 2008, FAME-08 was conducted at Finokalia, on the island of Crete, Greece. The purpose of the study was to characterize the physical and chemical properties of aged aerosol and to investigate new particle formation. Measurements included aerosol and air ion size distributions, size-resolved chemical composition, organic aerosol thermal volatility, water uptake and particle optical properties (light scattering and absorption. Statistical analysis of the aerosol mass concentration variations revealed the absence of diurnal patterns suggesting the lack of strong local sources. Sulfates accounted for approximately half of the particulate matter less than 1 micrometer in diameter (PM1 and organics for 28%. The PM1 organic aerosol fraction was highly oxidized with 80% water soluble. The supermicrometer particles were dominated by crustal components (50%, sea salt (24% and nitrates (16%. The organic carbon to elemental carbon (OC/EC ratio correlated with ozone measurements but with a one-day lag. The average OC/EC ratio for the study period was equal to 5.4. For three days air masses from North Africa resulted in a 6-fold increase of particulate matter less than 10 micrometers in diameter (PM10 and a decrease of the OC/EC ratio by a factor of 2. Back trajectory analysis, based on FLEXPART footprint plots, identified five source regions (Athens, Greece, Africa, other continental and marine, each of which influenced the PM1 aerosol composition and properties. Marine air masses had the lowest PM1 concentrations and air masses from the Balkans, Turkey and Eastern Europe the highest.

  11. Characterization of aerosol chemical composition with aerosol mass spectrometry in Central Europe: an overview

    Directory of Open Access Journals (Sweden)

    V. A. Lanz

    2010-11-01

    burning (BBOA. OOA was ubiquitous, ranged between 36% and 94% of OA, and could be separated into a low-volatility and a semi-volatile fraction (LV-OOA and SV-OOA for all summer campaigns at low altitude sites. Wood combustion (BBOA accounted for a considerable fraction during wintertime (17–49% OA, particularly in narrow Alpine valleys BBOA was often the most abundant OA component. HOA/OA ratios were comparatively low for all campaigns (6–16% with the exception of on-road, mobile measurements (23% in the Rhine Valley. The abundance of the aerosol components and the retrievability of SV-OOA and LV-OOA are discussed in the light of atmospheric chemistry and physics.

  12. Study of Aerosol Chemical Composition Based on Aerosol Optical Properties

    Science.gov (United States)

    Berry, Austin; Aryal, Rudra

    2015-03-01

    We investigated the variation of aerosol absorption optical properties obtained from the CIMEL Sun-Photometer measurements over three years (2012-2014) at three AERONET sites GSFC; MD Science_Center and Tudor Hill, Bermuda. These sites were chosen based on the availability of data and locations that can receive different types of aerosols from land and ocean. These absorption properties, mainly the aerosol absorption angstrom exponent, were analyzed to examine the corresponding aerosol chemical composition. We observed that the retrieved absorption angstrom exponents over the two sites, GSFC and MD Science Center, are near 1 (the theoretical value for black carbon) and with low single scattering albedo values during summer seasons indicating presence of black carbon. Strong variability of aerosol absorption properties were observed over Tudor Hill and will be analyzed based on the air mass embedded from ocean side and land side. We will also present the seasonal variability of these properties based on long-range air mass sources at these three sites. Brent Holben, NASA GSFC, AERONET, Jon Rodriguez.

  13. Global simulations of aerosol processing in clouds

    Directory of Open Access Journals (Sweden)

    C. Hoose

    2008-12-01

    Full Text Available An explicit and detailed representation of in-droplet and in-crystal aerosol particles in stratiform clouds has been introduced in the global aerosol-climate model ECHAM5-HAM. The new scheme allows an evaluation of the cloud cycling of aerosols and an estimation of the relative contributions of nucleation and collision scavenging, as opposed to evaporation of hydrometeors in the global aerosol processing by clouds. On average an aerosol particle is cycled through stratiform clouds 0.5 times. The new scheme leads to important changes in the simulated fraction of aerosol scavenged in clouds, and consequently in the aerosol wet deposition. In general, less aerosol is scavenged into clouds with the new prognostic treatment than what is prescribed in standard ECHAM5-HAM. Aerosol concentrations, size distributions, scavenged fractions and cloud droplet concentrations are evaluated and compared to different observations. While the scavenged fraction and the aerosol number concentrations in the marine boundary layer are well represented in the new model, aerosol optical thickness, cloud droplet number concentrations in the marine boundary layer and the aerosol volume in the accumulation and coarse modes over the oceans are overestimated. Sensitivity studies suggest that a better representation of below-cloud scavenging, higher in-cloud collision coefficients, or a reduced water uptake by seasalt aerosols could reduce these biases.

  14. Global simulations of aerosol processing in clouds

    Directory of Open Access Journals (Sweden)

    C. Hoose

    2008-07-01

    Full Text Available An explicit and detailed representation of in-droplet and in-crystal aerosol particles in stratiform clouds has been introduced in the global aerosol-climate model ECHAM5-HAM. The new scheme allows an evaluation of the cloud cycling of aerosols and an estimation of the relative contributions of nucleation and collision scavenging, as opposed to evaporation of hydrometeors in the global aerosol processing by clouds. On average an aerosol particle is cycled through stratiform clouds 0.5 times. The new scheme leads to important changes in the simulated fraction of aerosol scavenged in clouds, and consequently in the aerosol wet deposition. In general, less aerosol is scavenged into clouds with the new prognostic treatment than what is prescribed in standard ECHAM5-HAM. Aerosol concentrations, size distributions, scavenged fractions and cloud droplet concentrations are evaluated and compared to different observations. While the scavenged fraction and the aerosol number concentrations in the marine boundary layer are well represented in the new model, aerosol optical thickness, cloud droplet number concentrations in the marine boundary layer and the aerosol volume in the accumulation and coarse modes over the oceans are overestimated. Sensitivity studies suggest that a better representation of below-cloud scavenging, higher in-cloud collision coefficients, or a reduced water uptake by seasalt aerosols could reduce these biases.

  15. An overview of geoengineering of climate using stratospheric sulphate aerosols.

    Science.gov (United States)

    Rasch, Philip J; Tilmes, Simone; Turco, Richard P; Robock, Alan; Oman, Luke; Chen, Chih-Chieh; Stenchikov, Georgiy L; Garcia, Rolando R

    2008-11-13

    We provide an overview of geoengineering by stratospheric sulphate aerosols. The state of understanding about this topic as of early 2008 is reviewed, summarizing the past 30 years of work in the area, highlighting some very recent studies using climate models, and discussing methods used to deliver sulphur species to the stratosphere. The studies reviewed here suggest that sulphate aerosols can counteract the globally averaged temperature increase associated with increasing greenhouse gases, and reduce changes to some other components of the Earth system. There are likely to be remaining regional climate changes after geoengineering, with some regions experiencing significant changes in temperature or precipitation. The aerosols also serve as surfaces for heterogeneous chemistry resulting in increased ozone depletion. The delivery of sulphur species to the stratosphere in a way that will produce particles of the right size is shown to be a complex and potentially very difficult task. Two simple delivery scenarios are explored, but similar exercises will be needed for other suggested delivery mechanisms. While the introduction of the geoengineering source of sulphate aerosol will perturb the sulphur cycle of the stratosphere signicantly, it is a small perturbation to the total (stratosphere and troposphere) sulphur cycle. The geoengineering source would thus be a small contributor to the total global source of 'acid rain' that could be compensated for through improved pollution control of anthropogenic tropospheric sources. Some areas of research remain unexplored. Although ozone may be depleted, with a consequent increase to solar ultraviolet-B (UVB) energy reaching the surface and a potential impact on health and biological populations, the aerosols will also scatter and attenuate this part of the energy spectrum, and this may compensate the UVB enhancement associated with ozone depletion. The aerosol will also change the ratio of diffuse to direct energy

  16. An overview of geoengineering of climate using stratospheric sulphate aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Rasch, Philip J.; Tilmes, S.; Turco, Richard P.; Robock, Alan; Oman, Luke; Chen, Chih-Chieh; Stenchikov, Georgiy; Garcia, Rolando R.

    2010-01-01

    We provide an overview of geoengineering by stratospheric sulphate aerosols. The state of understanding about this topic as of early 2008 is reviewed, summarizing the past 30 years of work in the area, highlighting some very recent studies using climate models, and discussing methods used to deliver sulphur species to the stratosphere. The studies reviewed here suggest that sulphate aerosols can counteract the globally averaged temperature increase associated with increasing greenhouse gases, and reduce changes to some other components of the Earth system. There are likely to be remaining regional climate changes after geoengineering, with some regions experiencing significant changes in temperature or precipitation. The aerosols also serve as surfaces for heterogeneous chemistry resulting in increased ozone depletion. The delivery of sulphur species to the stratosphere in a way that will produce particles of the right size is shown to be a complex and potentially very difficult task. Two simple delivery scenarios are explored, but similar exercises will be needed for other suggested delivery mechanisms. While the introduction of the geoengineering source of sulphate aerosol will perturb the sulphur cycle of the stratosphere signicantly, it is a small perturbation to the total (stratosphere and troposphere) sulphur cycle. The geoengineering source would thus be a small contributor to the total global source of ‘acid rain’ that could be compensated for through improved pollution control of anthropogenic tropospheric sources. Some areas of research remain unexplored. Although ozone may be depleted, with a consequent increase to solar ultraviolet-B (UVB) energy reaching the surface and a potential impact on health and biological populations, the aerosols will also scatter and attenuate this part of the energy spectrum, and this may compensate the UVB enhancement associated with ozone depletion. The aerosol will also change the ratio of diffuse to direct energy

  17. Ice Nucleation Activity of Various Agricultural Soil Dust Aerosol Particles

    Science.gov (United States)

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

    2016-04-01

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

  18. Aerosol optical, microphysical and radiative properties at regional background insular sites in the western Mediterranean

    Science.gov (United States)

    Sicard, Michaël; Barragan, Rubén; Dulac, François; Alados-Arboledas, Lucas; Mallet, Marc

    2016-09-01

    In the framework of the ChArMEx (the Chemistry-Aerosol Mediterranean Experiment; http://charmex.lsce.ipsl.fr/) program, the seasonal variability of the aerosol optical, microphysical and radiative properties derived from AERONET (Aerosol Robotic Network; http://aeronet.gsfc.nasa.gov/) is examined in two regional background insular sites in the western Mediterranean Basin: Ersa (Corsica Island, France) and Palma de Mallorca (Mallorca Island, Spain). A third site, Alborán (Alborán Island, Spain), with only a few months of data is considered for examining possible northeast-southwest (NE-SW) gradients of the aforementioned aerosol properties. The AERONET dataset is exclusively composed of level 2.0 inversion products available during the 5-year period 2011-2015. AERONET solar radiative fluxes are compared with ground- and satellite-based flux measurements. To the best of our knowledge this is the first time that AERONET fluxes are compared with measurements at the top of the atmosphere. Strong events (with an aerosol optical depth at 440 nm greater than 0.4) of long-range transport aerosols, one of the main drivers of the observed annual cycles and NE-SW gradients, are (1) mineral dust outbreaks predominant in spring and summer in the north and in summer in the south and (2) European pollution episodes predominant in autumn. A NE-SW gradient exists in the western Mediterranean Basin for the aerosol optical depth and especially its coarse-mode fraction, which all together produces a similar gradient for the aerosol direct radiative forcing. The aerosol fine mode is rather homogeneously distributed. Absorption properties are quite variable because of the many and different sources of anthropogenic particles in and around the western Mediterranean Basin: North African and European urban areas, the Iberian and Italian peninsulas, most forest fires and ship emissions. As a result, the aerosol direct forcing efficiency, more dependent to absorption than the absolute

  19. Rural continental aerosol properties and processes observed during the Hohenpeissenberg Aerosol Characterization Experiment (HAZE2002

    Directory of Open Access Journals (Sweden)

    N. Hock

    2007-06-01

    Full Text Available Detailed investigations of the chemical and microphysical properties of rural continental aerosols were performed during the HAZE2002 experiment, which was conducted in May 2002 at the Meteorological Observatory Hohenpeissenberg (DWD in Southern Germany.

    The online measurement data and techniques included: size-resolved chemical composition of submicron particles by aerosol mass spectrometry (AMS; total particle number concentrations and size distributions over the diameter range of 3 nm to 9 μm (CPC, SMPS, OPC; monoterpenes determined by gas chromatography- ion trap mass spectrometry; OH and H2SO4 determined by atmospheric pressure chemical ionization mass spectrometry (CIMS. Filter sampling and offline analytical techniques were used to determine: fine particle mass (PM2.5, organic, elemental and total carbon in PM2.5 (OC2.5, EC2.5, TC2.5, and selected organic compounds (dicarboxylic acids, polycyclic aromatic hydrocarbons, proteins.

    Overall, the non-refractory components of submicron particles detected by aerosol mass spectrometry (PM1, 6.6±5.4 μg m−3, arithmetic mean and standard deviation accounted for ~62% of PM2.5 determined by filter gravimetry (10.6±4.7 μg m−3. The relative proportions of non-refractory submicron particle components were: 11% ammonium, 19% nitrate, 20% sulfate, and 50% organics (OM1. In spite of strongly changing meteorological conditions and absolute concentration levels of particulate matter (3–13 μg m−3 PM1, OM1 was closely correlated with PM1 (r2=0.9 indicating a near-constant ratio of non-refractory organics and inorganics. In contrast, the ratio of nitrate to sulfate was highly dependent on temperature (14–32°C and relative humidity (20–100%, which could be explained by thermodynamic model calculations of NH3/HNO3/NH4NO3 gas-particle partitioning. From the combination

  20. Methods of analyzing composition of aerosol particles

    Science.gov (United States)

    Reilly, Peter T.A.

    2013-02-12

    An aerosol particle analyzer includes a laser ablation chamber, a gas-filled conduit, and a mass spectrometer. The laser ablation chamber can be operated at a low pressure, which can be from 0.1 mTorr to 30 mTorr. The ablated ions are transferred into a gas-filled conduit. The gas-filled conduit reduces the electrical charge and the speed of ablated ions as they collide and mix with buffer gases in the gas-filled conduit. Preferably, the gas filled-conduit includes an electromagnetic multipole structure that collimates the nascent ions into a beam, which is guided into the mass spectrometer. Because the gas-filled conduit allows storage of vast quantities of the ions from the ablated particles, the ions from a single ablated particle can be analyzed multiple times and by a variety of techniques to supply statistically meaningful analysis of composition and isotope ratios.

  1. A ten-year global record of absorbing aerosols above clouds from OMI's near-UV observations

    Science.gov (United States)

    Jethva, Hiren; Torrres, Omar; Ahn, Changwoo

    2016-05-01

    Aerosol-cloud interaction continues to be one of the leading uncertain components of climate models, primarily due to the lack of an adequate knowledge of the complex microphysical and radiative processes associated with the aerosolcloud system. The situations when aerosols and clouds are found in the same atmospheric column, for instance, when light-absorbing aerosols such as biomass burning generated carbonaceous particles or wind-blown dust overlay low-level cloud decks, are commonly found over several regional of the world. Contrary to the cloud-free scenario over dark surface, for which aerosols are known to produce a net cooling effect (negative radiative forcing) on climate, the overlapping situation of absorbing aerosols over cloud can potentially exert a significant level of atmospheric absorption and produces a positive radiative forcing at top-of-atmosphere. The magnitude of direct radiative effects of aerosols above cloud depends directly on the aerosol loading, microphysical-optical properties of the aerosol layer and the underlying cloud deck, and geometric cloud fraction. We help in addressing this problem by introducing a novel product of optical depth of absorbing aerosols above clouds retrieved from near-UV observations made by the Ozone Monitoring Instrument (OMI) on board NASA's Aura platform. The presence of absorbing aerosols above cloud reduces the upwelling radiation reflected by cloud and produces a strong `color ratio' effect in the near-UV region, which can be unambiguously detected in the OMI measurements. Physically based on this effect, the OMACA algorithm retrieves the optical depths of aerosols and clouds simultaneously under a prescribed state of atmosphere. The algorithm architecture and results from a ten-year global record including global climatology of frequency of occurrence and above-cloud aerosol optical depth, and a discussion on related future field campaigns are presented.

  2. Evaluating model parameterizations of submicron aerosol scattering and absorption with in situ data from ARCTAS 2008

    Science.gov (United States)

    Alvarado, Matthew J.; Lonsdale, Chantelle R.; Macintyre, Helen L.; Bian, Huisheng; Chin, Mian; Ridley, David A.; Heald, Colette L.; Thornhill, Kenneth L.; Anderson, Bruce E.; Cubison, Michael J.; Jimenez, Jose L.; Kondo, Yutaka; Sahu, Lokesh K.; Dibb, Jack E.; Wang, Chien

    2016-07-01

    Accurate modeling of the scattering and absorption of ultraviolet and visible radiation by aerosols is essential for accurate simulations of atmospheric chemistry and climate. Closure studies using in situ measurements of aerosol scattering and absorption can be used to evaluate and improve models of aerosol optical properties without interference from model errors in aerosol emissions, transport, chemistry, or deposition rates. Here we evaluate the ability of four externally mixed, fixed size distribution parameterizations used in global models to simulate submicron aerosol scattering and absorption at three wavelengths using in situ data gathered during the 2008 Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaign. The four models are the NASA Global Modeling Initiative (GMI) Combo model, GEOS-Chem v9-02, the baseline configuration of a version of GEOS-Chem with online radiative transfer calculations (called GC-RT), and the Optical Properties of Aerosol and Clouds (OPAC v3.1) package. We also use the ARCTAS data to perform the first evaluation of the ability of the Aerosol Simulation Program (ASP v2.1) to simulate submicron aerosol scattering and absorption when in situ data on the aerosol size distribution are used, and examine the impact of different mixing rules for black carbon (BC) on the results. We find that the GMI model tends to overestimate submicron scattering and absorption at shorter wavelengths by 10-23 %, and that GMI has smaller absolute mean biases for submicron absorption than OPAC v3.1, GEOS-Chem v9-02, or GC-RT. However, the changes to the density and refractive index of BC in GC-RT improve the simulation of submicron aerosol absorption at all wavelengths relative to GEOS-Chem v9-02. Adding a variable size distribution, as in ASP v2.1, improves model performance for scattering but not for absorption, likely due to the assumption in ASP v2.1 that BC is present at a constant mass fraction

  3. Climate-aerosol interactions over the Mediterranean region: a regional coupled modelling approach

    Science.gov (United States)

    Nabat, Pierre; Somot, Samuel; Mallet, Marc

    2015-04-01

    The Mediterranean basin is affected by numerous and various aerosols which have a high spatio-temporal variability. These aerosols directly interact with solar and thermal radiation, and indirectly with clouds and atmospheric dynamics. Therefore they can have an important impact on the regional climate. This work, located at the boundary between the ChArMEx and HyMeX programs, considers a coupled regional modeling approach in order to address the questions of the aerosol-radiation-cloud interactions with regards to the climate variability over the Mediterranean. In order to improve the characterization of Mediterranean aerosols, a new interannual monthly climatology of aerosol optical depth has been developed from a blended product based on both satellite-derived and model-simulated datasets. This dataset, available for every regional climate model over the Mediterranean for the 1979-2012 period, has been built to obtain the best possible estimate of the atmospheric aerosol content for the five species at stake (sulfate, black carbon, organic matter, desert dust and sea salt particles). Simulation ensembles, which have been carried out over the 2003-2009 period with and without aerosols, show a major impact on the regional climate. The seasonal cycle and the spatial patterns of the Mediterranean climate are significantly modified, as well as some specific situations such as the heat wave in July 2006 strengthened by the presence of desert dust particles. The essential role of the Mediterranean sea surface temperature is highlighted, and enables to understand the induced changes on air-sea fluxes and the consequences on regional climate. Oceanic convection is also strengthened by aerosols. In addition, the decrease in anthropogenic aerosols observed for more than thirty years is shown to significantly contribute to the observed Euro-Mediterranean climatic trends in terms of surface radiation and temperature. Besides, an interactive aerosol scheme has been developed

  4. Spontaneous Aerosol Ejection: Origin of Inorganic Particles in Biomass Pyrolysis.

    Science.gov (United States)

    Teixeira, Andrew R; Gantt, Rachel; Joseph, Kristeen E; Maduskar, Saurabh; Paulsen, Alex D; Krumm, Christoph; Zhu, Cheng; Dauenhauer, Paul J

    2016-06-08

    At high thermal flux and temperatures of approximately 500 °C, lignocellulosic biomass transforms to a reactive liquid intermediate before evaporating to condensable bio-oil for downstream upgrading to renewable fuels and chemicals. However, the existence of a fraction of nonvolatile compounds in condensed bio-oil diminishes the product quality and, in the case of inorganic materials, catalyzes undesirable aging reactions within bio-oil. In this study, ablative pyrolysis of crystalline cellulose was evaluated, with and without doped calcium, for the generation of inorganic-transporting aerosols by reactive boiling ejection from liquid intermediate cellulose. Aerosols were characterized by laser diffraction light scattering, inductively coupled plasma spectroscopy, and high-speed photography. Pyrolysis product fractionation revealed that approximately 3 % of the initial feed (both organic and inorganic) was transported to the gas phase as aerosols. Large bubble-to-aerosol size ratios and visualization of significant late-time ejections in the pyrolyzing cellulose suggest the formation of film bubbles in addition to the previously discovered jet formation mechanism.

  5. Development of a high-spectral-resolution lidar for continuous observation of aerosols in South America

    Science.gov (United States)

    Jin, Yoshitaka; Sugimoto, Nobuo; Nishizawa, Tomoaki; Ristori, Pablo; Papandrea, Sebastian; Otero, Lidia; Quel, Eduardo; Mizuno, Akira

    2016-05-01

    Continuous monitoring of aerosol profiles using lidar is helpful for a quasi-real-time indication of aerosol concentration. For instance, volcanic ash concentration and its height distribution are essential information for plane flights. Depolarization ratio and multi-wavelength measurements are useful for characterizing aerosol types such as volcanic ash, smoke, dust, sea-salt, and air pollution aerosols. High spectral resolution lidar (HSRL) and Raman scattering lidar can contribute to such aerosol characterization significantly since extinction coefficients can be measured independently from backscattering coefficients. In particular, HSRL can measure aerosol extinction during daytime and nighttime with a high sensitivity. We developed an HSRL with the iodine filter method for continuous observation of aerosols at 532nm in the northern region of Argentina in the framework of the South American Environmental Atmospheric Risk Management Network (SAVER.Net)/SATREPS project. The laser wavelength of the HSRL was controlled by a feedback system to tune the laser wavelength to the center of an iodine absorption line. The stability of the laser wavelength with the system satisfied the requirement showing very small systematic errors in the retrieval of extinction and backscatter.

  6. Aerosol microphysical processes and properties in Canadian boreal forest fire plumes measured during BORTAS

    Science.gov (United States)

    Sakamoto, Kimiko; Allen, James; Coe, Hugh; Taylor, Jonathan; Duck, Thomas; Pierce, Jeffrey

    2013-04-01

    Biomass burning emissions contribute significantly to aerosol concentrations and clound condensation nuclei in many regions of the atmosphere. Plume-aerosol characteristics vary according to age, fuel type, and region. These differences are poorly represented in regional and global aerosol models, and they contribute to large uncertainties in predicted size distributions in biomass-burning-dominated regions. The Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS) measurement campaign was designed to invesigate boreal biomass burning emissions over Atlantic Canada during July-August of 2011. Aged (2-3 days) biomass burning aerosols originating from western Ontario were measured by an SMPS and AMS on board the British Atmospheric Research Aircraft. We identify the presence of plumes using CO concentrations and acetonitrile enhancement ratios. In-plume aerosol size distributions were collected for six aged plume profiles. The size distributions show an accumulation-mode median diameter of ~240 nm. However, there are persistant nucleation and Aitken modes present in the profiles, even 2-3 days from the source. Without continuous nucleation and condensation (likely SOA production), these small modes would be lost by coagulation in less than 1 day. We use an aerosol microphysics plume model to estimate the mean nucleation and condensation rates necessary to maintain the small aerosols, and calculate how these processes enhance the total number of particles and cloud condensation nuclei in the aged plume.

  7. Factors Affecting Aerosol Radiative Forcing

    Science.gov (United States)

    Wang, Jingxu; Lin, Jintai; Ni, Ruijing

    2016-04-01

    Rapid industrial and economic growth has meant a large amount of aerosols in the atmosphere with strong radiative forcing (RF) upon the climate system. Over parts of the globe, the negative forcing of aerosols has overcompensated for the positive forcing of greenhouse gases. Aerosol RF is determined by emissions and various chemical-transport-radiative processes in the atmosphere, a multi-factor problem whose individual contributors have not been well quantified. In this study, we analyze the major factors affecting RF of secondary inorganic aerosols (SIOAs, including sulfate, nitrate and ammonium), primary organic aerosol (POA), and black carbon (BC). We analyze the RF of aerosols produced by 11 major regions across the globe, including but not limited to East Asia, Southeast Asia, South Asia, North America, and Western Europe. Factors analyzed include population size, per capita gross domestic production (GDP), emission intensity (i.e., emissions per unit GDP), chemical efficiency (i.e., mass per unit emissions) and radiative efficiency (i.e., RF per unit mass). We find that among the 11 regions, East Asia produces the largest emissions and aerosol RF, due to relatively high emission intensity and a tremendous population size. South Asia produce the second largest RF of SIOA and BC and the highest RF of POA, in part due to its highest chemical efficiency among all regions. Although Southeast Asia also has large emissions, its aerosol RF is alleviated by its lowest chemical efficiency. The chemical efficiency and radiative efficiency of BC produced by the Middle East-North Africa are the highest across the regions, whereas its RF is lowered by a small per capita GDP. Both North America and Western Europe have low emission intensity, compensating for the effects on RF of large population sizes and per capita GDP. There has been a momentum to transfer industries to Southeast Asia and South Asia, and such transition is expected to continue in the coming years. The

  8. Compression Ratio Adjuster

    Science.gov (United States)

    Akkerman, J. W.

    1982-01-01

    New mechanism alters compression ratio of internal-combustion engine according to load so that engine operates at top fuel efficiency. Ordinary gasoline, diesel and gas engines with their fixed compression ratios are inefficient at partial load and at low-speed full load. Mechanism ensures engines operate as efficiently under these conditions as they do at highload and high speed.

  9. Financial Key Ratios

    Directory of Open Access Journals (Sweden)

    Tănase Alin-Eliodor

    2014-08-01

    Full Text Available This article focuses on computing techniques starting from trial balance data regarding financial key ratios. There are presented activity, liquidity, solvency and profitability financial key ratios. It is presented a computing methodology in three steps based on a trial balance.

  10. MISR Aerosol Climatology Product V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This product is 1)the microphysical and scattering characteristics of pure aerosol upon which routine retrievals are based;2)mixtures of pure aerosol to be compared...

  11. Miniature Sensor for Aerosol Mass Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR project seeks to develop a miniature sensor for mass measurement of size-classified aerosols. A cascade impactor will be used to classify aerosol sample...

  12. Aerosol Emission during Human Speech

    Science.gov (United States)

    Asadi, Sima; Ristenpart, William

    2016-11-01

    The traditional emphasis for airborne disease transmission has been on coughing and sneezing, which are dramatic expiratory events that yield easily visible droplets. Recent research suggests that normal speech can release even larger quantities of aerosols that are too small to see with the naked eye, but are nonetheless large enough to carry a variety of pathogens (e.g., influenza A). This observation raises an important question: what types of speech emit the most aerosols? Here we show that the concentration of aerosols emitted during healthy human speech is positively correlated with both the amplitude (loudness) and fundamental frequency (pitch) of the vocalization. Experimental measurements with an aerodynamic particle sizer (APS) indicate that speaking in a loud voice (95 decibels) yields up to fifty times more aerosols than in a quiet voice (75 decibels), and that sounds associated with certain phonemes (e.g., [a] or [o]) release more aerosols than others. We interpret these results in terms of the egressive airflow rate associated with each phoneme and the corresponding fundamental frequency, which is known to vary significantly with gender and age. The results suggest that individual speech patterns could affect the probability of airborne disease transmission.

  13. Intercomparison and closure calculations using measurements of aerosol species and optical properties during the Yosemite Aerosol Characterization Study

    Science.gov (United States)

    Malm, William C.; Day, Derek E.; Carrico, Christian; Kreidenweis, Sonia M.; Collett, Jeffrey L.; McMeeking, Gavin; Lee, Taehyoung; Carrillo, Jacqueline; Schichtel, Bret

    2005-07-01

    Physical and optical properties of inorganic aerosols have been extensively studied, but less is known about carbonaceous aerosols, especially as they relate to the non-urban settings such as our nation's national parks and wilderness areas. Therefore an aerosol characterization study was conceived and implemented at one national park that is highly impacted by carbonaceous aerosols, Yosemite. The primary objective of the study was to characterize the physical, chemical, and optical properties of a carbon-dominated aerosol, including the ratio of total organic matter weight to organic carbon, organic mass scattering efficiencies, and the hygroscopic characteristics of a carbon-laden ambient aerosol, while a secondary objective was to evaluate a variety of semi-continuous monitoring systems. Inorganic ions were characterized using 24-hour samples that were collected using the URG and Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring systems, the micro-orifice uniform deposit impactor (MOUDI) cascade impactor, as well as the semi-continuous particle-into-liquid sampler (PILS) technology. Likewise, carbonaceous material was collected over 24-hour periods using IMPROVE technology along with the thermal optical reflectance (TOR) analysis, while semi-continuous total carbon concentrations were measured using the Rupprecht and Patashnick (R&P) instrument. Dry aerosol number size distributions were measured using a differential mobility analyzer (DMA) and optical particle counter, scattering coefficients at near-ambient conditions were measured with nephelometers fitted with PM10 and PM2.5 inlets, and "dry" PM2.5 scattering was measured after passing ambient air through Perma Pure Nafion® dryers. In general, the 24-hour "bulk" measurements of various aerosol species compared more favorably with each other than with the semi-continuous data. Semi-continuous sulfate measurements correlated well with the 24-hour measurements, but were biased low by

  14. Specialized ratio analysis.

    Science.gov (United States)

    Wyer, J C; Salzinger, F H

    1983-01-01

    Many common management techniques have little use in managing a medical group practice. Ratio analysis, however, can easily be adapted to the group practice setting. Acting as broad-gauge indicators, financial ratios provide an early warning of potential problems and can be very useful in planning for future operations. The author has gathered a collection of financial ratios which were developed by participants at an education seminar presented for the Virginia Medical Group Management Association. Classified according to the human element, system component, and financial factor, the ratios provide a good sampling of measurements relevant to medical group practices and can serve as an example for custom-tailoring a ratio analysis system for your medical group.

  15. Molecular Characterization of Free Tropospheric Aerosol Collected at the Pico Mountain Observatory

    Science.gov (United States)

    Dzepina, K.; Mazzoleni, C.; Fialho, P. J.; China, S.; Zhang, B.; Owen, R. C.; Helmig, D.; Jacques, H.; Kumar, S.; Perlinger, J. A.; Kramer, L. J.; Dziobak, M.; Ampadu, M.; Olsen, S. C.; Wuebbles, D. J.; Mazzoleni, L. R.

    2014-12-01

    Long-range transported free tropospheric aerosol was sampled at the Pico Mountain Observatory (38°28'15''N, 28°24'14''W; 2225 m amsl) on Pico Island of the Azores archipelago in the North Atlantic ~3900 km east and downwind of North America. Filter-collected aerosol during summer 2012 was analyzed for organic and elemental carbon, and inorganic ions. The average ambient concentration of aerosol was 0.9 μg m-3. Organic aerosol contributed the majority of mass (57%), followed by sulfate (21%) and nitrate (17%). Filter-collected aerosol was positively correlated with continuous aerosol measurements of black carbon, light scattering and number concentration. Water-soluble organic compounds (WSOC) from 9/24 and 9/25 aerosol samples collected during a pollution event were analyzed using ultrahigh-resolution FT-ICR MS. FLEXPART retroplume analysis shows the air masses were very aged (> 12 days). About 4000 molecular formulas were assigned to each of the mass spectra between m/z 100-1000. The majority of the assigned molecular formulas have unsaturated structures with CHO and CHNO elemental compositions. WSOC have an average O/C ratio of ~0.45, relatively low compared to O/C ratios of other aged aerosol which might be the result of evaporation and fragmentation during long-range transport. The increase in aerosol loading during 9/24 was linked to biomass burning emissions from North America by FLEXPART retroplumes and MODIS fire counts. This was confirmed with WSOC biomass burning markers and with the morphology and mixing state of particles as determined by scanning electron microscopy. The presence of markers characteristic of aqueous-phase reactions of biomass burning phenolic species suggests that the aerosol collected at Pico had undergone cloud processing. The air masses on 9/25 were more aged (~15 days) and influenced by marine emissions, as indicated by organosulfates and species characteristic for marine aerosol (e.g. fatty acids). The change in air masses for

  16. Variation of the vertical distribution of Nabro volcano aerosol layers in the stratosphere observed by LIDAR

    Science.gov (United States)

    Noh, Young Min; Shin, Dong Ho; Müller, Detlef

    2017-04-01

    We present results of the vertical distribution variation of volcanic aerosol layers in the upper troposphere and lower stratosphere. The data were taken with our multiwavelength aerosol Raman lidar at Gwangju (35.10° N, 126.53° E), Korea. The volcanic ash particles and gases were released around 12 June 2011 during the eruption of the Nabro volcano (13.37° N, 41.7° E) in Eritrea, east Africa. Forward trajectory computations show that the volcanic aerosols were advected from North Africa to East Asia. The first measurement of the aerosol layer over Korea was on 19 June 2011. The aerosol layers appeared between 15 km and 17 km height asl (above sea level). The maximum value of the aerosol layer of the particle backscatter coefficient (1.5 ± 0.3 Mm-1 sr-1) and the linear particle depolarization ratio at 532 nm (2.2%) were observed at 16.4 km height asl. We continuously probed the upper troposphere and lower stratosphere for this volcanic aerosol layer during the following 6 months, until December 2011. The volcanic aerosol layer showed a single-peak of the particle backscatter coefficient and a comparably narrow vertical thickness at our observation site at the beginning of our observation period (i.e. comparably soon after the initial eruption period). After that initial period the vertical distribution of the plume changed. Multiple peaks and a comparably broad geometrical thickness developed with progressing observation time. The vertical thickness of the volcanic aerosol layer expanded up to 10 km by 3 August 2011. The linear particle depolarization ratios were larger in the lower part of the aerosol layer than the upper part of the aerosol layer. We observed a strong variation of the AOD (aerosol optical depth) in the first two months of our lidar observations. After these two months the AOD gradually decreased with time from September to December 20111 and the maximum particle backscatter coefficients consistently decreased. The corresponding e

  17. Requirements For Lidar Aerosol and Ozone Measurements

    Science.gov (United States)

    Frey, S.; Woeste, L.

    Laser remote sensing is the preferable method, when spatial-temporal resolved data is required. Data from stationary laser remote sensing devices at the earth surface give a very good impression about daily, annual and in general time trends of a measurand and can be compared sometimes to airborne instruments to get a direct link between optical and other methods. Space borne measurements on the other hand are the only possibility for obtaining as much data, as modeller wish to have to initialise, compare or validate there computation. But in this case it is very difficult to get the input in- formation, which is necessary for good quantitative analysis as well as to find points for comparison. In outer space and other harsh field environments only the simplest and most robust equipment for the respective purpose should be applied, to ensure a long-term stable operation. The first question is: what do we have to know about the properties of the atmosphere to get reliable data from instruments, which are just simple enough?, and secondly: how to set-up the instruments? Even for the evaluation of backscatter coefficients a density profile and the so-called Lidar-ratio, the ratio of backscatter to total volume scatter intensity, is necessary. Raman Lidar is a possibility to handle this problem by measuring aerosol extinction profiles. But again a density profile and in addition a guess about the wavelength dependence of the aerosol extinc- tion between the Raman and laser wavelength are required. Unfortunately the tech- nique for Raman measurements is much more sensible and less suited for space borne measurements, because of the much smaller back scatter cross sections and the result- ing weak signals. It becomes worth, when we will have to maintain special laser with colours at molecular absorption bands in outer space, to measure gas concentration. I want to present simulation of optical systems for laser remote sensing, experimental experiences and compare air

  18. Origins of atmospheric aerosols. Basic concepts on aerosol main physical properties; L`aerosol atmospherique: ses origines quelques notions sur les principales proprietes physiques des aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Renoux, A. [Paris-12 Univ., 94 - Creteil (France). Laboratoire de Physique des aerosols et de transferts des contaminations

    1996-12-31

    Natural and anthropogenic sources of atmospheric aerosols are reviewed and indications of their concentrations and granulometry are given. Calculation of the lifetime of an atmospheric aerosol of a certain size is presented and the various modes of aerosol granulometry and their relations with photochemical and physico-chemical processes in the atmosphere are discussed. The main physical, electrical and optical properties of aerosols are also presented: diffusion coefficient, dynamic mobility and relaxation time, Stokes number, limit rate of fall, electrical mobility, optical diffraction

  19. Luxury uptake of aerosol iron by Trichodesmium in the western tropical North Atlantic

    Science.gov (United States)

    Chen, Ying; Tovar-Sanchez, Antonio; Siefert, Ronald L.; Sañudo-Wilhelmy, Sergio A.; Zhuang, Guoshun

    2011-09-01

    Dust transported from North Africa carries micronutrient iron (Fe) to the western tropical North Atlantic (WTNA) which may significantly influence the metabolism of the N2-fixing cyanobacteria, Trichodesmium. For the first time, we conducted shipboard incubation experiments using freshly collected aerosol, seawater, and Trichodesmium colonies. Trichodesmium assimilated significant amount of aerosol Fe up to 14 times higher than the control. The uptake amount increased proportionally to the P: Fe ratio that Trichodesmium initially contained and to the aerosol Fe added and leached to the incubation solution. Trichodesmium assimilated more aerosol Fe than needed for its maximum growth (0.14 d-1) demonstrating a high capacity of luxury uptake of Fe from the dust.

  20. Combined effects of organic aerosol loading and fog processing on organic aerosols oxidation and composition

    Science.gov (United States)

    Chakraborty, Abhishek; Tripathi, Sachchida; Gupta, Tarun

    2016-04-01

    Fog is a natural meteorological phenomenon that occurs throughout the world, it contains substantial quantity of liquid water and generally seen as a natural cleansing agent but it also has the potential to form highly oxidized secondary organic aerosols (SOA) via aqueous processing of ambient aerosols. On the other hand higher organic aerosols (OA) loading tend to decrease the overall oxidation level (O/C) of the particle phase organics, due to enhanced partitioning of less oxidized organics from gas to particle phase. However, combined impact of these two parameters; aqueous oxidation and OA loading, on the overall oxidation ratio (O/C) of ambient OA has never been studied. To assess this, real time ambient sampling using HR-ToF-AMS was carried out at Kanpur, India from 15 December 2014 - 10 February 2015. In first 3 weeks of this campaign, very high OA loading is (134 ± 42 μg/m3) observed (termed as high loading or HL period) while loading is substantially reduced from 2nd January, 2016 (56 ± 20 μg/m3, termed as low loading or LL period) . However, both the loading period was affected by several fog episodes (10 in HL and 7 in LL), thus providing the opportunity of studying the combined effects of fog and OA loading on OA oxidation. It is found that O/C ratio is very strongly anti-correlated with OA loading in both the loading period, however, slope of this ant-correlation is much steep during HL period than in LL period. Source apportionment of OA revealed that there is drastic change in the types of OA from HL to LL period, clearly indicating difference in OA composition from HL to LL period. During foggy night continuous oxidation of OA is observed from early evening to early morning with 15-20% enhancement in O/C ratio, while the same is absent during non-foggy period, clearly indicating the efficient fog processing of ambient OA. It is also found that night time fog aqueous oxidation can be as effective as daytime photo chemistry in oxidation of OA. Fog

  1. Speciation of Radiocesium and Radioiodine in Aerosols from Tsukuba after the Fukushima Nuclear Accident

    DEFF Research Database (Denmark)

    Xu, Sheng; Zhang, Luyuan; Freeman, Stewart P. H. T.

    2015-01-01

    Aerosol samples were collected from Tsukuba, Japan, soon after the 2011 Fukushima nuclear accident and analyzed for speciation of radiocesium and radioiodine to explore their chemical behavior and isotopic ratios after the release. Most Cs-134 and Cs-137 were bound in organic matter (53-91%) and ......Aerosol samples were collected from Tsukuba, Japan, soon after the 2011 Fukushima nuclear accident and analyzed for speciation of radiocesium and radioiodine to explore their chemical behavior and isotopic ratios after the release. Most Cs-134 and Cs-137 were bound in organic matter (53...

  2. ATI TDA 5A aerosol generator evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Gilles, D.A.

    1998-07-27

    Oil based aerosol ``Smoke`` commonly used for testing the efficiency and penetration of High Efficiency Particulate Air filters (HEPA) and HEPA systems can produce flammability hazards that may not have been previously considered. A combustion incident involving an aerosol generator has caused an investigation into the hazards of the aerosol used to test HEPA systems at Hanford.

  3. DARE: a dedicated aerosols retrieval instrument

    NARCIS (Netherlands)

    Court, A.J.; Smorenburg, K.; Courrèges-Lacoste, G.B.; Visser, H.; Leeuw, G. de; Decae, R.

    2004-01-01

    Satellite remote sensing of aerosols is a largely unresolved problem. A dedicated instrument aimed at aerosols would be able to reduce the large uncertainties connected to this kind of remote sensing. TNO is performing a study of a space based instrument for aerosol measurements, together with the s

  4. Wind reduction by aerosol particles

    Science.gov (United States)

    Jacobson, Mark Z.; Kaufman, Yoram J.

    2006-12-01

    Aerosol particles are known to affect radiation, temperatures, stability, clouds, and precipitation, but their effects on spatially-distributed wind speed have not been examined to date. Here, it is found that aerosol particles, directly and through their enhancement of clouds, may reduce near-surface wind speeds below them by up to 8% locally. This reduction may explain a portion of observed ``disappearing winds'' in China, and it decreases the energy available for wind-turbine electricity. In California, slower winds reduce emissions of wind-driven soil dust and sea spray. Slower winds and cooler surface temperatures also reduce moisture advection and evaporation. These factors, along with the second indirect aerosol effect, may reduce California precipitation by 2-5%, contributing to a strain on water supply.

  5. Aerosol retrieval experiments in the ESA Aerosol_cci project

    Directory of Open Access Journals (Sweden)

    T. Holzer-Popp

    2013-08-01

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

  6. Aerosol retrieval experiments in the ESA Aerosol_cci project

    Science.gov (United States)

    Holzer-Popp, T.; de Leeuw, G.; Griesfeller, J.; Martynenko, D.; Klüser, L.; Bevan, S.; Davies, W.; Ducos, F.; Deuzé, J. L.; Graigner, R. G.; Heckel, A.; von Hoyningen-Hüne, W.; Kolmonen, P.; Litvinov, P.; North, P.; Poulsen, C. A.; Ramon, D.; Siddans, R.; Sogacheva, L.; Tanre, D.; Thomas, G. E.; Vountas, M.; Descloitres, J.; Griesfeller, J.; Kinne, S.; Schulz, M.; Pinnock, S.

    2013-08-01

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

  7. Identification of aerosol types over Indo-Gangetic Basin: implications to optical properties and associated radiative forcing.

    Science.gov (United States)

    Tiwari, S; Srivastava, A K; Singh, A K; Singh, Sachchidanand

    2015-08-01

    The aerosols in the Indo-Gangetic Basin (IGB) are a mixture of sulfate, dust, black carbon, and other soluble and insoluble components. It is a challenge not only to identify these various aerosol types, but also to assess the optical and radiative implications of these components. In the present study, appropriate thresholds for fine-mode fraction and single-scattering albedo have been used to first identify the aerosol types over IGB. Four major aerosol types may be identified as polluted dust (PD), polluted continental (PC), black carbon-enriched (BCE), and organic carbon-enriched (OCE). Further, the implications of these different types of aerosols on optical properties and radiative forcing have been studied. The aerosol products derived from CIMEL sun/sky radiometer measurements, deployed under Aerosol Robotic Network program of NASA, USA were used from four different sites Karachi, Lahore, Jaipur, and Kanpur, spread over Pakistan and Northern India. PD is the most dominant aerosol type at Karachi and Jaipur, contributing more than 50% of all the aerosol types. OCE, on the other hand, contributes only about 12-15% at all the stations except at Kanpur where its contribution is ∼38%. The spectral dependence of AOD was relatively low for PD aerosol type, with the lowest AE values (1.0). SSA was found to be the highest for OCE (>0.9) and the lowest for BCE (<0.9) type aerosols, with drastically different spectral variability. The direct aerosol radiative forcing at the surface and in the atmosphere was found to be the maximum at Lahore among all the four stations in the IGB.

  8. Aerosol single-scattering albedo retrieval over North Africa using critical reflectance

    Science.gov (United States)

    Wells, Kelley C.

    Geostationary Earth Radiation Budget (GERB) experiment, Atmospheric Radiation Measurement (ARM) program, and Clouds and the Earth's Radiant Energy System (CERES) data. Spectral SSA values retrieved at Banizoumbou result in TOA forcing estimates that agree with CERES measurements within +/- 5 W m-2 for dusty conditions; however, the retrieved SSA translates to a much larger positive TOA forcing than CERES in the presence of dust-biomass burning mixtures. At Tamanrasset, the retrieval captures changes in aerosol absorption from day to day, but the SSA appears to be biased high when compared to AERONET and CERES. This may be due to the higher surface reflectance in this region, an overestimation of the dust aerosol size, or changing background aerosol between the clean and polluted day. Our retrieval results indicate that we can be most confident in the retrieved SSA for scattering angles between 120° and 160°, satellite view angles less than ˜45°, and in cases when the background aerosol on the cleaner day is non-absorbing.

  9. Measurements of optical properties for tropospheric aerosols in the Artic; Messung von optischen Eigenschaften troposphaerischer Aerosole in der Arktis

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.

    2001-07-01

    Two different methods for the derivation of the altitude resolved aerosol extinction profiles are applied. The Klett method, which needs only the elastical backscattered lidar signal, allows the determination of the extinction coefficient indirectly at day and nighttime. For the Klett method an assumption of the extinction-to-backscatter ratio, often called 'lidar ratio', is necessary. This can be determined iteratively by combining with the airborne photometer measurements. With this method small scale inhomogenities and the high variability of fine structured aerosol layers can be recorded. In contract to this the Raman method allows to calculate the extinction coefficient without an assumption of the lidar ratio. Here only the Raman backscattered light from nitrogen is used. The procedure is limited in temporal and spatial resolution because the Raman backscatter cross section is smaller than the elastic backscatter cross section by three orders of magnitude. A sensitivity study shows the feasibility of this method. (orig.) [German] In dieser Arbeit werden zwei unterschiedliche Methoden zur Ableitung hochaufgeloester Extinktionsprofile des troposphaerischen Aerosols angewendet. Die Klett-Methode, in die ausschliesslich die elastisch rueckgestreuten Lidarsignale eingehen, erlaubt es indirekt auch waehrend des Polartages hochaufgeloeste Extinktionsprofile abzuleiten. Hierzu ist die Annahme ueber das Extinktions-zu-Rueckstreuverhaeltnisses, welches haeufig auch als Lidarverhaeltnis bezeichnet wird, notwendig. Dieses wird durch Kombination mit den flugzeuggetragenen Photometermessungen iteriert. Mit dieser Methode koennen somit auch kleinskalige Inhomogenitaeten aufgeloest und die hohe zeitliche Variabilitaet der Aerosolschichten erfasst werden. Im Gegensatz hierzu bietet die Raman-Methode den Vorteil, die Aerosol-Extinktion direkt ohne Annahme des Lidarverhaeltnisses abzuleiten. Bei der Ableitung der Aerosolextinktion gehen ausschliesslich die an

  10. Aerosol effects on deep convective clouds: impact of changes in aerosol size distribution and aerosol activation parameterization

    Science.gov (United States)

    Ekman, A. M. L.; Engström, A.; Söderberg, A.

    2010-03-01

    A cloud-resolving model including explicit aerosol physics and chemistry is used to study the impact of aerosols on deep convective strength. More specifically, by conducting six sensitivity series we examine how the complexity of the aerosol model, the size of the aerosols and the aerosol activation parameterization influence the aerosol-induced deep convective cloud sensitivity. Only aerosol effects on liquid droplet formation are considered. We find that an increased aerosol concentration generally results in stronger convection, which for the simulated case is in agreement with the conceptual model presented by Rosenfeld et al. (2008). However, there are two sensitivity series that do not display a monotonic increase in updraft velocity with increasing aerosol concentration. These exceptions illustrate the need to: 1) account for changes in evaporation processes and subsequent cooling when assessing aerosol effects on deep convective strength, 2) better understand graupel impaction scavenging of aerosols which may limit the number of CCN at a critical stage of cloud development and thereby dampen the convection, 3) increase our knowledge of aerosol recycling due to evaporation of cloud droplets. Furthermore, we find a significant difference in the aerosol-induced deep convective cloud sensitivity when using different complexities of the aerosol model and different aerosol activation parameterizations. For the simulated case, a 100% increase in aerosol concentration results in a difference in average updraft between the various sensitivity series which is as large as the average updraft increase itself. The model simulations also show that the change in graupel and rain formation is not necessarily directly proportional to the change in updraft velocity. For example, several of the sensitivity series display a decrease of the rain amount at the lowest model level with increasing updraft velocity. Finally, an increased number of aerosols in the Aitken mode (here

  11. Aerosol effects on deep convective clouds: impact of changes in aerosol size distribution and aerosol activation parameterization

    Directory of Open Access Journals (Sweden)

    A. M. L. Ekman

    2010-03-01

    Full Text Available A cloud-resolving model including explicit aerosol physics and chemistry is used to study the impact of aerosols on deep convective strength. More specifically, by conducting six sensitivity series we examine how the complexity of the aerosol model, the size of the aerosols and the aerosol activation parameterization influence the aerosol-induced deep convective cloud sensitivity. Only aerosol effects on liquid droplet formation are considered. We find that an increased aerosol concentration generally results in stronger convection, which for the simulated case is in agreement with the conceptual model presented by Rosenfeld et al. (2008. However, there are two sensitivity series that do not display a monotonic increase in updraft velocity with increasing aerosol concentration. These exceptions illustrate the need to: 1 account for changes in evaporation processes and subsequent cooling when assessing aerosol effects on deep convective strength, 2 better understand graupel impaction scavenging of aerosols which may limit the number of CCN at a critical stage of cloud development and thereby dampen the convection, 3 increase our knowledge of aerosol recycling due to evaporation of cloud droplets. Furthermore, we find a significant difference in the aerosol-induced deep convective cloud sensitivity when using different complexities of the aerosol model and different aerosol activation parameterizations. For the simulated case, a 100% increase in aerosol concentration results in a difference in average updraft between the various sensitivity series which is as large as the average updraft increase itself. The model simulations also show that the change in graupel and rain formation is not necessarily directly proportional to the change in updraft velocity. For example, several of the sensitivity series display a decrease of the rain amount at the lowest model level with increasing updraft velocity. Finally, an increased number of aerosols in the

  12. Field Trial of an Aerosol-Based Enclosure Sealing Technology

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, Curtis [Univ. of California, Davis, CA (United States); Springer, David [Univ. of California, Davis, CA (United States)

    2015-09-01

    This report presents the results from several demonstrations of a new method for sealing building envelope air leaks using an aerosol sealing process developed by the Western Cooling Efficiency Center at UC Davis. The process involves pressurizing a building while applying an aerosol sealant to the interior. As air escapes through leaks in the building envelope, the aerosol particles are transported to the leaks where they collect and form a seal that blocks the leak. Standard blower door technology is used to facilitate the building pressurization, which allows the installer to track the sealing progress during the installation and automatically verify the final building tightness. Each aerosol envelope sealing installation was performed after drywall was installed and taped, and the process did not appear to interrupt the construction schedule or interfere with other trades working in the homes. The labor needed to physically seal bulk air leaks in typical construction will not be replaced by this technology. However, this technology is capable of bringing the air leakage of a building that was built with standard construction techniques and HERS-verified sealing down to levels that would meet DOE Zero Energy Ready Homes program requirements. When a developer is striving to meet a tighter envelope leakage specification, this technology could greatly reduce the cost to achieve that goal by providing a simple and relatively low cost method for reducing the air leakage of a building envelope with little to no change in their common building practices.

  13. Strategy to use the Terra Aerosol Information to Derive the Global Aerosol Radiative Forcing of Climate

    Science.gov (United States)

    Kaufman, Yoram J.; Tanre, Didier; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Terra will derive the aerosol optical thickness and properties. The aerosol properties can be used to distinguish between natural and human-made aerosol. In the polar orbit Terra will measure aerosol only once a day, around 10:30 am. How will we use this information to study the global radiative impacts of aerosol on climate? We shall present a strategy to address this problem. It includes the following steps: - From the Terra aerosol optical thickness and size distribution model we derive the effect of aerosol on reflection of solar radiation at the top of the atmosphere. In a sensitivity study we show that the effect of aerosol on solar fluxes can be derived 10 times more accurately from the MODIS data than derivation of the optical thickness itself. Applications to data over several regions will be given. - Using 1/2 million AERONET global data of aerosol spectral optical thickness we show that the aerosol optical thickness and properties during the Terra 10:30 pass are equivalent to the daily average. Due to the aerosol lifetime of several days measurements at this time of the day are enough to assess the daily impact of aerosol on radiation. - Aerosol impact on the top of the atmosphere is only part of the climate question. The INDOEX experiment showed that addressing the impact of aerosol on climate, requires also measurements of the aerosol forcing at the surface. This can be done by a combination of measurements of MODIS and AERONET data.

  14. Systematic aerosol characterization by combining GOME-2 UV Aerosol Indices with trace gas concentrations

    Science.gov (United States)

    Penning de Vries, M.; Stammes, P.; Wagner, T.

    2012-04-01

    The task of determining aerosol type using passive remote sensing instruments is a daunting one. First, because the variety in aerosol (optical) properties is very large; and second, because the effect of aerosols on the detected top-of-atmosphere reflectance spectrum is smooth and mostly featureless. In addition, spectrometers like GOME-2 have a coarse spatial resolution, which makes aerosol characterization even more difficult due to interferences with clouds. On account of these problems, we do not attempt to derive aerosol properties from single measurements: instead, we combine time series of UV Aerosol Index and trace gas concentrations to derive the dominating aerosol type for each season. Aside from the Index values and trace gas concentrations themselves, the correlation between UV Aerosol Indices (which are indicative of aerosol absorption) with NO2, HCHO, and CHOCHO columns - or absence of it - provides clues to the (main) source of the aerosols in the investigated region and time range. For example: a high correlation of HCHO and Absorbing Aerosol Index points to aerosols from biomass burning, highly correlated CHOCHO, HCHO, and SCattering Index indicate biogenic secondary organic aerosols, and coinciding high NO2 concentrations with high SCattering Index values are associated with industrial and urban aerosols. We here present case studies for several regions to demonstrate the suitability of our approach. Then, we introduce a method to systematically derive the dominating aerosol type on a global scale on time scales varying from monthly to yearly.

  15. AERONET-based models of smoke-dominated aerosol near source regions and transported over oceans, and implications for satellite retrievals of aerosol optical depth

    Science.gov (United States)

    Sayer, A. M.; Hsu, N. C.; Eck, T. F.; Smirnov, A.; Holben, B. N.

    2014-10-01

    Smoke aerosols from biomass burning are an important component of the global aerosol system. Analysis of Aerosol Robotic Network (AERONET) retrievals of aerosol microphysical/optical parameters at 10 sites reveals variety between biomass burning aerosols in different global source regions, in terms of aerosol particle size and single scatter albedo (SSA). Case studies of smoke observed at coastal/island AERONET sites also mostly lie within the range of variability at the near-source sites. Differences between sites tend to be larger than variability at an individual site, although optical properties for some sites in different regions can be quite similar. Across the sites, typical midvisible SSA ranges from ~ 0.95-0.97 (sites dominated by boreal forest or peat burning, typically with larger fine-mode particle radius and spread) to ~ 0.88-0.9 (sites most influenced by grass, shrub, or crop burning, typically smaller fine-mode particle radius and spread). The tropical forest site Alta Floresta (Brazil) is closer to this second category, although with intermediate SSA ~ 0.92. The strongest absorption is seen in southern African savannah at Mongu (Zambia), with average midvisible SSA ~ 0.85. Sites with stronger absorption also tend to have stronger spectral gradients in SSA, becoming more absorbing at longer wavelengths. Microphysical/optical models are presented in detail so as to facilitate their use in radiative transfer calculations, including extension to UV (ultraviolet) wavelengths, and lidar ratios. One intended application is to serve as candidate optical models for use in satellite aerosol optical depth (AOD) retrieval algorithms. The models presently adopted by these algorithms over ocean often have insufficient absorption (i.e. too high SSA) to represent these biomass burning aerosols. The underestimates in satellite-retrieved AOD in smoke outflow regions, which have important consequences for applications of these satellite data sets, are consistent with

  16. In situ vertical profiles of aerosol extinction, mass, and composition over the southeast United States during SENEX and SEAC4RS: observations of a modest aerosol enhancement aloft

    Directory of Open Access Journals (Sweden)

    N. L. Wagner

    2015-02-01

    Full Text Available Vertical profiles of submicron aerosol over the southeastern United States (SEUS during the summertime from in situ aircraft-based measurements were used to construct aggregate profiles of chemical, microphysical, and optical properties. Shallow cumulus convection was observed during many profiles. These conditions enhance vertical transport of trace gases and aerosol and create a cloudy transition layer on top of the sub-cloud mixed layer. The trace gas and aerosol concentrations in the transition layer were modeled as a mixture with contributions from the mixed layer below and the free troposphere above. The amount of vertical mixing, or entrainment of air from the free troposphere, was quantified using the observed mixing ratio of carbon monoxide (CO. Although the median aerosol mass, extinction, and volume decreased with altitude in the transition layer, they were ~10% larger than expected from vertical mixing alone. This enhancement was likely due to secondary aerosol formation in the transition layer. Although the transition layer enhancements of the particulate sulfate and organic aerosol (OA were both similar in magnitude, only the enhancement of sulfate was statistically significant. The column integrated extinction, or aerosol optical depth (AOD, was calculated for each individual profile, and the transition layer enhancement of extinction typically contributed less than 10% to the total AOD. Our measurements and analysis were motivated by two recent studies that have hypothesized an enhanced layer of secondary organic aerosol (SOA aloft to explain the summertime enhancement of AOD (2–3 times greater than winter over the southeastern United States. In contrast to this hypothesis, the modest enhancement we observed in the transition layer was not dominated by OA and was not a large fraction of the summertime AOD.

  17. Water Soluble Ions in Bulk Aerosol During the WINTER 2015 Campaign.

    Science.gov (United States)

    Dibb, J. E.; Scheuer, E. M.; Brown, S. S.; Campuzano Jost, P.; Fibiger, D. L.; Guo, H.; Jimenez, J. L.; Lopez-Hilfiker, F.; McDuffie, E. E.; Schroder, J. C.; Sullivan, A.; Thornton, J. A.; Veres, P. R.; Weber, R. J.

    2015-12-01

    Aerosol samples were collected on filters from the NCAR C-130 during the WINTER campaign using an inlet believed to transmit particles up to 4 micron in diameter. Filter integration times were nominally 7 minutes. Aqueous extracts of the filter samples were analyzed by ion chromatography for 5 anions and 5 cations, we focus primarily on chloride and nitrate due to their roles coupling chlorine and nitrogen oxide chemistry. Comparison to measurements of submicron aerosol (by PILS and AMS) indicates that there was significant coarse chloride in the boundary layer on all WINTER flights, including the 7 flights over the continent. Significant super micron chloride at altitudes above 2 km was seen in just 3 of the filter samples from the entire mission, all of these were well inland. During the 6 flights over the Atlantic ocean we observed displacement of chloride from the dominant seasalt aerosol at times, but evidence for coarse mode nitrate or sulfate aerosol to explain this is less clear. While coarse aerosol chloride mixing ratios were sufficient to support observed production of nitryl chloride, no correlations between these compounds were observed on any flights. However, nitrate was positively correlated with nitryl chloride, as expected, on all flights when the latter exceeded several 100's of pptv for extended periods. Aerosol nitrate was also positively correlated with dinitrogen pentoxide when mixing ratios of the latter exceeded ~500 pptv for significant portions of a flight. On the WINTER flights in February aerosol nitrate was often more abundant than nitric acid, this was less often the case for the flights in March. This change in partitioning of nitrate between gas and particle phases reflects an increasing trend of nitric acid and a small decrease in abundance of aerosol nitrate through the campaign.

  18. Lidar detection of high concentrations of ozone and aerosol transported from northeastern Asia over Saga, Japan

    Science.gov (United States)

    Uchino, Osamu; Sakai, Tetsu; Izumi, Toshiharu; Nagai, Tomohiro; Morino, Isamu; Yamazaki, Akihiro; Deushi, Makoto; Yumimoto, Keiya; Maki, Takashi; Tanaka, Taichu Y.; Akaho, Taiga; Okumura, Hiroshi; Arai, Kohei; Nakatsuru, Takahiro; Matsunaga, Tsuneo; Yokota, Tatsuya

    2017-02-01

    To validate products of the Greenhouse gases Observing SATellite (GOSAT), we observed vertical profiles of aerosols, thin cirrus clouds, and tropospheric ozone with a mobile-lidar system that consisted of a two-wavelength (532 and 1064 nm) polarization lidar and a tropospheric ozone differential absorption lidar (DIAL). We used these lidars to make continuous measurements over Saga (33.24° N, 130.29° E) during 20-31 March 2015. High ozone and high aerosol concentrations were observed almost simultaneously in the altitude range 0.5-1.5 km from 03:00 to 20:00 Japan Standard Time (JST) on 22 March 2015. The maximum ozone volume mixing ratio was ˜ 110 ppbv. The maxima of the aerosol extinction coefficient and optical depth at 532 nm were 1.2 km-1 and 2.1, respectively. Backward trajectory analysis and the simulations by the Model of Aerosol Species IN the Global AtmospheRe (MASINGAR) mk-2 and the Meteorological Research Institute Chemistry-Climate Model, version 2 (MRI-CCM2), indicated that mineral dust particles from the Gobi Desert and an air mass with high ozone and aerosol (mainly sulfate) concentrations that originated from the North China Plain could have been transported over the measurement site within about 2 days. These high ozone and aerosol concentrations impacted surface air quality substantially in the afternoon of 22 March 2015. After some modifications of its physical and chemical parameters, MRI-CCM2 approximately reproduced the high ozone volume mixing ratio. MASINGAR mk-2 successfully predicted high aerosol concentrations, but the predicted peak aerosol optical thickness was about one-third of the observed value.

  19. Confined Aerosol Jet in Fiber Classification and Dustiness Measurement

    Science.gov (United States)

    Dubey, Prahit

    The focus of this dissertation is the numerical analysis of confined aerosol jets used in fiber classification and dustiness measurement. Of relevance to the present work are two devices, namely, the Baron Fiber Classifier (BFC), and the Venturi Dustiness Tester (VDT). The BFC is a device used to length-separate fibers, important for toxicological research. The Flow Combination Section (FCS) of this device consists of an upstream region, where an aerosol of uncharged fibers is introduced in the form of an annular jet, in-between two sheath flows. Length-separation occurs by dielectrophoresis, downstream of the FCS in the Fiber Classification Section (FClS). In its standard operation, BFC processes only small quantities of fibers. In order to increase its throughput, higher aerosol flow rates must be considered. The goal of the present investigation is to understand the interaction of sheath and aerosol flows inside the FCS, and to identify possible limits to increasing aerosol flow rates using Computational Fluid Dynamics (CFD). Simulations involve solution of Navier-Stokes equations for axisymmetric and 3D models of the FCS for six different flow rates, and a pure aerodynamic treatment of the aerosol jet. The results show that the geometry of the FCS, and the two sheath flows, are successful in preventing the emergence of vortices in the FCS for aerosol-to-sheath flow inlet velocity ratios below ≈ 50. For larger aerosol-to-sheath flow inlet velocity ratios, two vortices are formed, one near the inner cylinder and one near the outer cylinder. The VDT is a novel device for measuring the dustiness of powders, relevant for dust management and controlling hazardous exposure. It uses just 10 mg of the test powder for its operation, during which the powder is aerosolized and turbulently dispersed (Re = 19,900) for 1.5s into a 5.7 liter chamber; the aerosol is then gently sampled (Re = 2050) for 240s through two filters located at the chamber top. Pump-driven suction at

  20. Case study of modeled aerosol optical properties during the SAFARI 2000 campaign.

    Science.gov (United States)

    Kuzmanoski, Maja; Box, Michael A; Schmid, Beat; Russell, Philip B; Redemann, Jens

    2007-08-01

    We present modeled aerosol optical properties (single scattering albedo, asymmetry parameter, and lidar ratio) in two layers with different aerosol loadings and particle sizes, observed during the Southern African Regional Science Initiative 2,000 (SAFARI 2,000) campaign. The optical properties were calculated from aerosol size distributions retrieved from aerosol layer optical thickness spectra, measured using the NASA Ames airborne tracking 14-channel sunphotometer (AATS-14) and the refractive index based on the available information on aerosol chemical composition. The study focuses on sensitivity of modeled optical properties in the 0.3-1.5 microm wavelength range to assumptions regarding the mixing scenario. We considered two models for the mixture of absorbing and nonabsorbing aerosol components commonly used to model optical properties of biomass burning aerosol: a layered sphere with absorbing core and nonabsorbing shell and the Maxwell-Garnett effective medium model. In addition, comparisons of modeled optical properties with the measurements are discussed. We also estimated the radiative effect of the difference in aerosol absorption implied by the large difference between the single scattering albedo values (approximately 0.1 at midvisible wavelengths) obtained from different measurement methods for the case with a high amount of biomass burning particles. For that purpose, the volume fraction of black carbon was varied to obtain a range of single scattering albedo values (0.81-0.91 at lambda=0.50 microm). The difference in absorption resulted in a significant difference in the instantaneous radiative forcing at the surface and the top of the atmosphere (TOA) and can result in a change of the sign of the aerosol forcing at TOA from negative to positive.

  1. Sources and characteristics of sub-micron aerosols in the San Joaquin Valley, CA

    Science.gov (United States)

    Bahreini, R.; Middlebrook, A. M.; Brioude, J.; Brock, C. A.; de Gouw, J. A.; Hall, K.; Holloway, J. S.; Neuman, J.; Nowak, J. B.; Pollack, I. B.; Ryerson, T. B.; Warneke, C.; Parrish, D. D.

    2010-12-01

    The NOAA WP-3D aircraft performed several flights in the San Joaquin Valley (SJV), California during the CalNex-2010 (California Research at the Nexus of Air Quality and Climate Change) field project in May-June 2010. SJV is generally a rural valley, with a high concentration of feedlots and agricultural sites as well as urbanized centers such as Fresno and Bakersfield. Preliminary results on size-resolved chemical composition of sub-micron aerosols measured using a compact time-of-flight aerosol mass spectrometer, measurements of trace gases affecting secondary production of aerosols, and FLEXPART back trajectory analyses are presented in order to identify sources of aerosols transported to or produced in the valley. Observed enhancements in various trace gases and aerosol species indicate a mixed influence from urban, industrial, and animal feedlots in the SJV. Three distinct observations suggest a complex transport pattern of pollutants with different origins to and within the valley: 1) CO and NOx mixing ratios were prominent downwind of the urban areas in the valley; 2) SO2, aerosol organics and sulfate were higher closer to the foothills of the Sierra Nevada Mountains on the east of the valley; 3) high concentration of aerosol phase ammonium and nitrate were observed in NH3-rich air masses, directly downwind of the feedlots in the central part of the valley. Aerosol enhancements in each of these air mass categories relative to the background determine the relative contribution and significance of different sources to aerosol loadings in the valley. Differences in VOC measurements and meteorology will be explored to investigate the observed variation in characteristics of organics on different days.

  2. Difference and ratio plots

    DEFF Research Database (Denmark)

    Svendsen, Anders Jørgen; Holmskov, U; Bro, Peter

    1995-01-01

    hitherto unnoted differences between controls and patients with either rheumatoid arthritis or systemic lupus erythematosus. For this we use simple, but unconventional, graphic representations of the data, based on difference plots and ratio plots. Differences between patients with Burkitt's lymphoma...... and systemic lupus erythematosus from another previously published study (Macanovic, M. and Lachmann, P.J. (1979) Clin. Exp. Immunol. 38, 274) are also represented using ratio plots. Our observations indicate that analysis by regression analysis may often be misleading....

  3. Modeling of secondary organic aerosol yields from laboratory chamber data

    Directory of Open Access Journals (Sweden)

    M. N. Chan

    2009-04-01

    Full Text Available A product-specific model for secondary organic aerosol (SOA formation and composition based on equilibrium gas-particle partitioning is evaluated. The model is applied to represent laboratory data on the ozonolysis of α-pinene under dry, dark, and low-NOx conditions in the presence of ammonium sulfate seed aerosol. Using five major identified products, the model is fit to the chamber data. From the optimal fitting, SOA oxygen-to-carbon (O/C and hydrogen-to-carbon (H/C ratios are modeled. The discrepancy between measured H/C ratios and those based on the oxidation products used in the model fitting suggests the potential importance of particle-phase reactions. Data fitting is also carried out using the volatility basis set, wherein oxidation products are parsed into volatility bins. The product-specific model is best used for an SOA precursor for which a substantial fraction of the aerosol-phase oxidation products has been identified.

  4. Satellite observations of aerosol and CO over Mexico City

    Science.gov (United States)

    Massie, Steven T.; Gille, John C.; Edwards, David P.; Nandi, Sreela

    The development of remote sensing satellite technology potentially will lead to the technical means to monitor air pollution emitted from large cities on a global basis. This paper presents observations by the moderate resolution imaging spectroradiometer (MODIS) and measurements of pollution in the troposphere (MOPITT) experiments of aerosol optical depths and CO mixing ratios, respectively, in the vicinity of Mexico City to illustrate current satellite capabilities. MOPITT CO mixing ratios over Mexico City, averaged between January-March 2002-2005, are 19% above regional values and the CO plume extends over 10° 2 in the free troposphere at 500 hPa. Time series of Red Automatica de Monitoreo Ambiental (RAMA) PM10, and (Aerosol Robotic Network) AERONET and MODIS aerosol optical depths, and RAMA and MOPITT CO time series are inter-compared to illustrate the different perspectives of ground based and satellite instrumentation. Finally, we demonstrate, by examining MODIS and MOPITT data in April 2003, that satellite data can be used to identify episodes in which pollution form fires influences the time series of ground based and satellite observations of urban pollution.

  5. Characteristics, sources, and transport of aerosols measured in spring 2008 during the aerosol, radiation, and cloud processes affecting Arctic Climate (ARCPAC) Project

    Science.gov (United States)

    Brock, C. A.; Cozic, J.; Bahreini, R.; Froyd, K. D.; Middlebrook, A. M.; McComiskey, A.; Brioude, J.; Cooper, O. R.; Stohl, A.; Aikin, K. C.; de Gouw, J. A.; Fahey, D. W.; Ferrare, R. A.; Gao, R.-S.; Gore, W.; Holloway, J. S.; Hübler, G.; Jefferson, A.; Lack, D. A.; Lance, S.; Moore, R. H.; Murphy, D. M.; Nenes, A.; Novelli, P. C.; Nowak, J. B.; Ogren, J. A.; Peischl, J.; Pierce, R. B.; Pilewskie, P.; Quinn, P. K.; Ryerson, T. B.; Schmidt, K. S.; Schwarz, J. P.; Sodemann, H.; Spackman, J. R.; Stark, H.; Thomson, D. S.; Thornberry, T.; Veres, P.; Watts, L. A.; Warneke, C.; Wollny, A. G.

    2011-03-01

    We present an overview of the background, scientific goals, and execution of the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) project of April 2008. We then summarize airborne measurements, made in the troposphere of the Alaskan Arctic, of aerosol particle size distributions, composition, and optical properties and discuss the sources and transport of the aerosols. The aerosol data were grouped into four categories based on gas-phase composition. First, the background troposphere contained a relatively diffuse, sulfate-rich aerosol extending from the top of the sea-ice inversion layer to 7.4 km altitude. Second, a region of depleted (relative to the background) aerosol was present within the surface inversion layer over sea-ice. Third, layers of dense, organic-rich smoke from open biomass fires in southern Russia and southeastern Siberia were frequently encountered at all altitudes from the top of the inversion layer to 7.1 km. Finally, some aerosol layers were dominated by components originating from fossil fuel combustion. Of these four categories measured during ARCPAC, the diffuse background aerosol was most similar to the average springtime aerosol properties observed at a long-term monitoring site at Barrow, Alaska. The biomass burning (BB) and fossil fuel layers were present above the sea-ice inversion layer and did not reach the sea-ice surface during the course of the ARCPAC measurements. The BB aerosol layers were highly scattering and were moderately hygroscopic. On average, the layers produced a noontime net heating of ~0.1 K day-1 between 3 and 7 km and a slight cooling at the surface. The ratios of particle mass to carbon monoxide (CO) in the BB plumes, which had been transported over distances >5000 km, were comparable to the high end of literature values derived from previous measurements in wildfire smoke. These ratios suggest minimal precipitation scavenging and removal of the BB particles between the time they were

  6. Characteristics, sources, and transport of aerosols measured in spring 2008 during the aerosol, radiation, and cloud processes affecting Arctic Climate (ARCPAC Project

    Directory of Open Access Journals (Sweden)

    C. A. Brock

    2011-03-01

    Full Text Available We present an overview of the background, scientific goals, and execution of the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC project of April 2008. We then summarize airborne measurements, made in the troposphere of the Alaskan Arctic, of aerosol particle size distributions, composition, and optical properties and discuss the sources and transport of the aerosols. The aerosol data were grouped into four categories based on gas-phase composition. First, the background troposphere contained a relatively diffuse, sulfate-rich aerosol extending from the top of the sea-ice inversion layer to 7.4 km altitude. Second, a region of depleted (relative to the background aerosol was present within the surface inversion layer over sea-ice. Third, layers of dense, organic-rich smoke from open biomass fires in southern Russia and southeastern Siberia were frequently encountered at all altitudes from the top of the inversion layer to 7.1 km. Finally, some aerosol layers were dominated by components originating from fossil fuel combustion.

    Of these four categories measured during ARCPAC, the diffuse background aerosol was most similar to the average springtime aerosol properties observed at a long-term monitoring site at Barrow, Alaska. The biomass burning (BB and fossil fuel layers were present above the sea-ice inversion layer and did not reach the sea-ice surface during the course of the ARCPAC measurements. The BB aerosol layers were highly scattering and were moderately hygroscopic. On average, the layers produced a noontime net heating of ~0.1 K day−1 between 3 and 7 km and a slight cooling at the surface. The ratios of particle mass to carbon monoxide (CO in the BB plumes, which had been transported over distances >5000 km, were comparable to the high end of literature values derived from previous measurements in wildfire smoke. These ratios suggest minimal precipitation scavenging and removal of the BB

  7. Characteristics, sources, and transport of aerosols measured in spring 2008 during the aerosol, radiation, and cloud processes affecting Arctic climate (ARCPAC project

    Directory of Open Access Journals (Sweden)

    C. A. Brock

    2010-11-01

    Full Text Available We present an overview of the background, scientific goals, and execution of the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC project of April 2008. We then summarize airborne measurements, made in the troposphere of the Alaskan Arctic, of aerosol particle size distributions, composition, and optical properties and discuss the sources and transport of the aerosols. The aerosol data were grouped into four categories based on gas-phase composition. First, the background troposphere contained a relatively diffuse, sulfate-rich aerosol extending from the top of the sea-ice inversion layer to 7.4 km altitude. Second, a region of depleted (relative to the background aerosol was present within the surface inversion layer over sea-ice. Third, layers of dense, organic-rich smoke from open biomass fires in Southern Russia and Southeastern Siberia were frequently encountered at all altitudes from the top of the inversion layer to 7.1 km. Finally, some aerosol layers were dominated by components originating from fossil fuel combustion.

    Of these four categories measured during ARCPAC, the diffuse background aerosol was most similar to the average springtime aerosol properties observed at a long-term monitoring site at Barrow, Alaska. The biomass burning (BB and fossil fuel layers were present above the sea-ice inversion layer and did not reach the sea-ice surface during the course of the ARCPAC measurements. The BB aerosol layers were highly scattering and were moderately hygroscopic. On average, the layers produced a noontime net heating of ~0.1 K day−1 between 2 and 7 km and a~slight cooling at the surface. The ratios of particle mass to carbon monoxide (CO in the BB plumes, which had been transported over distances >5000 km, were comparable to the high end of literature values derived from previous measurements in fresh wildfire smoke. These ratios suggest minimal precipitation scavenging and removal of

  8. Source apportionment of carbonaceous aerosol in southern Sweden

    Directory of Open Access Journals (Sweden)

    J. Genberg

    2011-05-01

    Full Text Available A one-year study was performed at the Vavihill background station in southern Sweden to estimate the anthropogenic contribution to the carbonaceous aerosol. Weekly samples of the particulate matter PM10 were collected on quartz filters, and the amounts of organic carbon, elemental carbon, radiocarbon (14C and levoglucosan were measured. This approach enabled source apportionment of the total carbon in the PM10 fraction using the concentration ratios of the sources. The sources considered in this study were emissions from the combustion of fossil fuels and biomass, as well as biogenic sources. During the summer, the carbonaceous aerosol mass was dominated by compounds of biogenic origin (82 %, which are associated with biogenic primary and secondary organic aerosols. During the winter months, biomass combustion (38 % and fossil fuel combustion (33 % were the main contributors to the carbonaceous aerosol. Elemental carbon concentrations in winter were about twice as large as during summer, and can be attributed to biomass combustion, probably from domestic wood burning. The contribution of fossil fuels to elemental carbon was stable throughout the year, although the fossil contribution to organic carbon increased during the winter. Thus, the organic aerosol originated mainly from natural sources during the summer and from anthropogenic sources during the winter. The result of this source apportionment was compared with results from the EMEP model. The model and measurements were generally consistent for total atmospheric organic carbon, however, the contribution of the sources varied substantially. E.g. the biomass burning contributions of OC were underestimated by the model by a factor of 8.2 compared to the measurements.

  9. A Model Simulation of Pinatubo Volcanic Aerosols in the Stratosphere

    Science.gov (United States)

    Zhao , Jing-xia; Turco, Richard P.; Toon, Owen B.

    1995-01-01

    A one-dimensional, time-dependent model is used to study the chemical, microphysical, and radiative properties of volcanic aerosols produced by the Mount Pinatubo eruption on June 15, 1991. Our model treats gas-phase sulfur photochemistry, gas-to-particle conversion of sulfur, and the microphysics of sulfate aerosols and ash particles under stratospheric conditions. The dilution and diffusion of the volcanic eruption clouds are also accounted for in these conditions. Heteromolecular homogeneous and heterogeneous binary H2SO4/H2O nucleation, acid and water condensational growth, coagulation, and gravitational sedimentation are treated in detail in the model. Simulations suggested that after several weeks, the volcanic cloud was composed mainly of sulfuric acid/water droplets produced in situ from the SO2 emissions. The large amounts of SO2 (around 20 Mt) injected into the stratosphere by the Pinatubo eruption initiated homogeneous nucleation which generated a high concentration of small H2SO4/H2O droplets. These newly formed particles grew rapidly by condensation and coagulation in the first few months and then reach their stabilized sizes with effective radii in a range between 0.3 and 0.5 micron approximately one-half year after the eruption. The predicted volcanic cloud parameters reasonably agree with measurements in term of the vertical distribution and lifetime of the volcanic aerosols, their basic microphysical structures (e.g., size distribution, concentration, mass ratio, and surface area) and radiative properties. The persistent volcanic aerosols can produce significant anomalies in the radiation field, which have important climatic consequences. The large enhancement in aerosol surface area can result in measurable global stratospheric ozone depletion.

  10. Mass Concentration and Mineralogical Characteristics Aerosol Particles Collected at Dunhuang During ACE-Asia

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Measurements were performed in spring 2001 and 2002 to determine the characteristics of soil dust in the Chinese desert region of Dunhuang, one of the ground sites of the Asia-Pacific Regional Aerosol Characterization Experiment (ACE-Asia). The mean mass concentrations of total suspended particle matter during the spring of 2001 and 2002 were 317 μg m-3 and 307 μg m-3, respectively. Eleven dust storm events were observed with a mean aerosol concentration of 1095 μg m-3, while the non-dusty days with calm or weak wind speed had a background aerosol loading of 196 μg m-3 on average in the springtime.The main minerals detected in the aerosol samples by X-ray diffraction were illite, kaolinite, chlorite, quartz,feldspar, calcite and dolomite. Gypsum, halite and amphibole were also detected in a few samples. The mineralogical data also show that Asian dust is characterized by a kaolinite to chlorite (K/C) ratio lower than 1 whereas Saharan dust exhibits a K/C ratio larger than 2. Air mass back-trajectory analysis show that three families of pathways are associated with the aerosol particle transport to Dunhuang, but these have similar K/C ratios, which further demonstrates that the mineralogical characteristics of Asian dust are different from African dust.

  11. A mathematical model of aerosol holding chambers

    DEFF Research Database (Denmark)

    Zak, M; Madsen, J; Berg, E

    1999-01-01

    A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol...... in the chamber with time. Four different spacers were connected via filters to a mechanical lung model, and aerosol delivery during "breathing" was determined from drug recovery from the filters. The formula correctly predicted the delivery of budesonide aerosol from the AeroChamber (Trudell Medical, London...

  12. A closure study of aerosol optical properties at a regional background mountainous site in Eastern China

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Liang [Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Yin, Yan, E-mail: yinyan@nuist.edu.cn [Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Xiao, Hui [Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Yu, Xingna [Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Hao, Jian; Chen, Kui [Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044 (China); and others

    2016-04-15

    There is a large uncertainty in evaluating the radiative forcing from aerosol–radiation and aerosol–cloud interactions due to the limited knowledge on aerosol properties. In-situ measurements of aerosol physical and chemical properties were carried out in 2012 at Mt. Huang (the Yellow Mountain), a continental background mountainous site in eastern China. An aerosol optical closure study was performed to verify the model outputs by using the measured aerosol optical properties, in which a spherical Mie model with assumptions of external and core–shell mixtures on the basis of a two-component optical aerosol model and high size-segregated element carbon (EC) ratio was applied. Although the spherical Mie model would underestimate the real scattering with increasing particle diameters, excellent agreement between the calculated and measured values was achieved with correlation coefficients above 0.98. Sensitivity experiments showed that the EC ratio had a negligible effect on the calculated scattering coefficient, but largely influenced the calculated absorption coefficient. The high size-segregated EC ratio averaged over the study period in the closure was enough to reconstruct the aerosol absorption coefficient in the Mie model, indicating EC size resolution was more important than time resolution in retrieving the absorption coefficient in the model. The uncertainties of calculated scattering and absorption coefficients due to the uncertainties of measurements and model assumptions yielded by a Monte Carlo simulation were ± 6% and ± 14% for external mixture and ± 9% and ± 31% for core–shell mixture, respectively. This study provided an insight into the inherent relationship between aerosol optical properties and physicochemical characteristics in eastern China, which could supplement the database of aerosol optical properties for background sites in eastern China and provide a method for regions with similar climate. - Highlights: • A spherical Mie

  13. Latitudinal distributions of organic nitrogen and organic carbon in marine aerosols over the western North Pacific

    Directory of Open Access Journals (Sweden)

    Y. Miyazaki

    2010-11-01

    Full Text Available Marine aerosol samples were collected over the western North Pacific along the latitudinal transect from 44° N to 10° N in late summer 2008 for measurements of organic nitrogen (ON and organic carbon (OC as well as isotopic ratios of total nitrogen (TN and total carbon (TC. Increased concentrations of methanesulfonic acid (MSA and diethylammonium (DEA+ at 40–44° N and subtropical regions (10–20° N together with averaged satellite chlorophyll a data and 5-day back trajectories suggest a significant influence of marine biological activities on aerosols in these regions. ON exhibited increased concentrations up to 260 ngN m−3 in these marine biologically influenced aerosols. Water-insoluble organic nitrogen (WION was found to be the most abundant nitrogen in the aerosols, accounting for 55 ± 16% of total aerosol nitrogen. In particular, the average WION/ON ratio was as high as 0.93 ± 0.07 at 40–44° N. These results suggest that marine biological sources significantly contributed to ON, a majority of which is composed of water-insoluble fractions in the study region. Analysis of the stable carbon isotopic ratios13C indicated that, on average, marine-derived carbon accounted for ~88 ± 12% of total carbon in the aerosols. In addition, the δ13C increased from −22 to −20‰ when ON/OC ratios increased from 0.15 to 0.35 in marine biologically influenced aerosols. These results clearly show that organic nitrogen is enriched in organic aerosols originated from an oceanic region with high biological productivity, indicating a preferential transfer of nitrogen-containing organic compounds from the sea surface to the marine atmosphere. Both WION concentrations and WION/water-insoluble organic carbon (WIOC ratios showed positive correlations with local wind speeds, suggesting that sea-to-air emissions of ON via sea spray significantly contributes to marine organic aerosols over the

  14. Latitudinal distributions of organic nitrogen and organic carbon in marine aerosols over the western North Pacific

    Directory of Open Access Journals (Sweden)

    Y. Miyazaki

    2011-04-01

    Full Text Available Marine aerosol samples were collected over the western North Pacific along the latitudinal transect from 44° N to 10° N in late summer 2008 for measurements of organic nitrogen (ON and organic carbon (OC as well as isotopic ratios of total nitrogen (TN and total carbon (TC. Increased concentrations of methanesulfonic acid (MSA and diethylammonium (DEA+ at 40–44° N and subtropical regions (10–20° N together with averaged satellite chlorophyll-a data and 5-day back trajectories suggest a significant influence of marine biological activities on aerosols in these regions. ON exhibited increased concentrations up to 260 ngN m−3 in these marine biologically influenced aerosols. Water-insoluble organic nitrogen (WION was found to be the most abundant nitrogen in the aerosols, accounting for 55 ± 16% of total aerosol nitrogen. In particular, the average WION/ON ratio was as high as 0.93 ± 0.07 at 40–44° N. These results suggest that marine biological sources significantly contributed to ON, a majority of which is composed of water-insoluble fractions in the study region. Analysis of the stable carbon isotopic ratios13C indicated that, on average, marine-derived carbon accounted for ~88 ± 12% of total carbon in the aerosols. In addition, the δ13C showed higher values (from −22 to −20‰ when ON/OC ratios increased from 0.15 to 0.35 in marine biologically influenced aerosols. These results clearly show that organic nitrogen is enriched in organic aerosols originated from an oceanic region with high biological productivity, indicating a preferential transfer of nitrogen-containing organic compounds from the sea surface to the marine atmosphere. Both WION concentrations and WION/water-insoluble organic carbon (WIOC ratios tended to increase with increasing local wind speeds, indicating that sea-to-air emissions of ON via sea spray contribute significantly to the marine organic

  15. Characteristics of carbonaceous aerosols emitted from peatland fire in Riau, Sumatra, Indonesia

    Science.gov (United States)

    Fujii, Yusuke; Iriana, Windy; Oda, Masafumi; Puriwigati, Astiti; Tohno, Susumu; Lestari, Puji; Mizohata, Akira; Huboyo, Haryono Setiyo

    2014-04-01

    Biomass burning is a significant source of fine particulate matter (PM2.5). Forest, bush, and peat fires in Kalimantan and Sumatra, Indonesia are major sources of transboundary haze pollution in Southeast Asia. However, limited data exist regarding the chemical characteristics of aerosols at sources. We conducted intensive field studies in Riau Province, Sumatra, Indonesia, during the peatland fire and non-burning seasons in 2012. We characterized PM2.5 carbonaceous aerosols emitted from peatland fire based on ground-based source-dominated sampling. PM2.5 aerosols were collected with two mini-volume samplers using Teflon and quartz fiber filters. Background aerosols were also sampled during the transition period between the non-burning and fire seasons. We analyzed the carbonaceous content (organic carbon (OC) and elemental carbon (EC)) by a thermal optical reflectance utilizing the IMPROVE_A protocol and the major organic components of the aerosols by a gas chromatography/mass spectrometry. PM2.5 aerosols emitted from peatland fire were observed in high concentrations of 7120 ± 3620 μg m-3 and were primarily composed of OC (71.0 ± 5.11% of PM2.5 mass). Levoglucosan exhibited the highest total ion current and was present at concentrations of 464 ± 183 μg m-3. The OC/EC ratios (36.4 ± 9.08), abundances of eight thermally-derived carbon fractions, OC/Levoglucosan ratios (10.6 ± 1.96), and Levoglucosan/Mannosan ratios (10.6 ± 2.03) represent a signature profile that is inherent in peatland fire. These data will be useful in identifying contributions from single or multiple species in atmospheric aerosol samples collected from peatland fires.

  16. Secondary organic aerosol formation from biomass burning intermediates: phenol and methoxyphenols

    Directory of Open Access Journals (Sweden)

    L. D. Yee

    2013-08-01

    Full Text Available The formation of secondary organic aerosol from oxidation of phenol, guaiacol (2-methoxyphenol, and syringol (2,6-dimethoxyphenol, major components of biomass burning, is described. Photooxidation experiments were conducted in the Caltech laboratory chambers under low-NOx (2O2 as the OH source. Secondary organic aerosol (SOA yields (ratio of mass of SOA formed to mass of primary organic reacted greater than 25% are observed. Aerosol growth is rapid and linear with the primary organic conversion, consistent with the formation of essentially non-volatile products. Gas- and aerosol-phase oxidation products from the guaiacol system provide insight into the chemical mechanisms responsible for SOA formation. Syringol SOA yields are lower than those of phenol and guaiacol, likely due to novel methoxy group chemistry that leads to early fragmentation in the gas-phase photooxidation. Atomic oxygen to carbon (O : C ratios calculated from high-resolution-time-of-flight Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS measurements of the SOA in all three systems are ~ 0.9, which represent among the highest such ratios achieved in laboratory chamber experiments and are similar to that of aged atmospheric organic aerosol. The global contribution of SOA from intermediate volatility and semivolatile organic compounds has been shown to be substantial (Pye and Seinfeld, 2010. An approach to representing SOA formation from biomass burning emissions in atmospheric models could involve one or more surrogate species for which aerosol formation under well-controlled conditions has been quantified. The present work provides data for such an approach.

  17. Sources and composition of urban aerosol particles

    Directory of Open Access Journals (Sweden)

    M. Vogt

    2011-09-01

    Full Text Available From May 2008 to March 2009 aerosol emissions were measured using the eddy covariance method covering the size range 0.25 to 2.5 μm diameter (Dp from a 105 m tower, in central Stockholm, Sweden. Supporting chemical aerosol data were collected at roof and street level. Results show that the inorganic fraction of sulfate, nitrate, ammonium and sea salt accounts for approximately 15% of the total aerosol mass <1 μm Dp (PM1 with water soluble soil contributing 11% and water insoluble soil 47%. Carbonaceous compounds were at the most 27% of PM1 mass. It was found that heating the air from the tower to 200 °C resulted in the loss of approximately 60% of the aerosol volume at 0.25 μm Dp whereas only 40% of the aerosol volume was removed at 0.6 μm Dp. Further heating to 300 °C caused very little additional losses <0.6 μm Dp. The chemical analysis did not include carbonaceous compounds, but based on the difference between the total mass concentration and the sum of the analyzed non-carbonaceous materials, it can be assumed that the non-volatile particulate material (heated to 300 °C consists mainly of carbonaceous compounds, including elemental carbon. Furthermore, it was found that the non-volatile particle fraction <0.6 μm Dp correlated (r2 = 0.4 with the BC concentration at roof level in the city, supporting the assumption that the non-volatile material consists of carbonaceous compounds. The average diurnal cycles of the BC emissions from road traffic (as inferred from the ratio of the incremental concentrations of nitrogen oxides (NOx and BC measured on a densely trafficked street and the fluxes of non-volatile material at tower level are in close agreement, suggesting a traffic source of BC. We have estimated the emission factors (EFs for non

  18. Influences of relative humidity and particle chemical composition on aerosol scattering properties during the 2006 PRD campaign

    Science.gov (United States)

    Liu, Xingang; Cheng, Yafang; Zhang, Yuanhang; Jung, Jinsang; Sugimoto, Nobuo; Chang, Shih-Yu; Kim, Young J.; Fan, Shaojia; Zeng, Limin

    In situ measurements of the physical, chemical, and optical properties of aerosols were carried out in Guangzhou city, China, from 1 to 31 July 2006 during the Pearl River Delta (PRD) Campaign. The light extinction coefficient of the ambient atmosphere, the aerosol scattering coefficient under dry conditions, the aerosol absorption coefficient under ambient conditions, NO 2 concentration, and relative humidity (RH) were measured by transmissionmeter, an integrating nephelometer, a multi-angle absorption photometer (MAAP), a NO X analyzer, and an automatic meteorological station, respectively. Meanwhile, the molecular scattering coefficient was calculated by the Rayleigh scattering function using the US Standard Atmosphere. A method to calculate the aerosol hygroscopic growth factor f(RH), defined as the ratio of the aerosol scattering coefficient under a wet condition to that under a dry condition (40% RH), is proposed based on these optical parameters. The mean and standard deviation aerosol hygroscopic growth factors at 80% RH ( f(RH)=80%) in Ganzhou were 2.04±0.28, 2.29±0.28, and 2.68±0.59 for urban aerosols, mixed aerosols, and marine aerosols, respectively, with the air mass classification being based on the air mass source region. The relationship between f(RH) and RH is fitted by empirical equations and the fitting parameters are calculated. The relationships between f(RH)=80% and total carbon mass fraction (TCF) in PM 2.5, the water-soluble mass fraction (WSF) in PM 10, and the sea-salt aerosol mass fraction (SSF) in PM 10 reveal that the hygroscopic properties of the observed aerosol have a good positive correlation with the WSF and SSF, but have a negative correlation with the TCF.

  19. Fine mode aerosol chemistry over a rural atmosphere near the north-east coast of Bay of Bengal in India

    Science.gov (United States)

    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.

  20. Measurement and Study of Lidar Ratio by Using a Raman Lidar in Central China.

    Science.gov (United States)

    Wang, Wei; Gong, Wei; Mao, Feiyue; Pan, Zengxin; Liu, Boming

    2016-05-18

    We comprehensively evaluated particle lidar ratios (i.e., particle extinction to backscatter ratio) at 532 nm over Wuhan in Central China by using a Raman lidar from July 2013 to May 2015. We utilized the Raman lidar data to obtain homogeneous aerosol lidar ratios near the surface through the Raman method during no-rain nights. The lidar ratios were approximately 57 ± 7 sr, 50 ± 5 sr, and 22 ± 4 sr under the three cases with obviously different pollution levels. The haze layer below 1.8 km has a large particle extinction coefficient (from 5.4e-4 m(-1) to 1.6e-4 m(-1)) and particle backscatter coefficient (between 1.1e-05 m(-1)sr(-1) and 1.7e-06 m(-1)sr(-1)) in the heavily polluted case. Furthermore, the particle lidar ratios varied according to season, especially between winter (57 ± 13 sr) and summer (33 ± 10 sr). The seasonal variation in lidar ratios at Wuhan suggests that the East Asian monsoon significantly affects the primary aerosol types and aerosol optical properties in this region. The relationships between particle lidar ratios and wind indicate that large lidar ratio values correspond well with weak winds and strong northerly winds, whereas significantly low lidar ratio values are associated with prevailing southwesterly and southerly wind.

  1. Coastal and open ocean aerosol characteristics: investigating the representativeness of coastal aerosol sampling over the North-East Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    M. Rinaldi

    2008-11-01

    Full Text Available In order to achieve a better understanding of the modifications of the physical and chemical properties of marine aerosol particles during transport from offshore to the coast, size distribution and chemical composition were measured concurrently in clean air masses over the open North Atlantic Ocean and at an Irish coastal site. Open ocean sampling was performed on board the oceanographic vessel Celtic Explorer sailing 100–300 km off the Irish west coast, while coastal measurements were performed at the Mace Head GAW station. The experiment took place between 11 June and 6 July 2006, during the period of phytoplankton bloom.

    The number size distribution and size-resolved chemical composition of coastal and open ocean samples were very similar, indicating homogeneous physical and chemical aerosol properties over a wide region in the marine boundary layer. The results also show that submicron chemical and physical aerosol properties measured at the coastal Mace Head Atmospheric Research Station were not unduly influenced by coastal artefacts and are thus representative of open water properties. Greater differences between the coastal site and the open ocean were observed for the aerosol supermicron sea spray components; this could be due to a variety of reasons, ranging from higher local wind speeds at the coastal site over the comparison period, to differences in sampling heights and increased local surf-zone production.

    Evidence of ageing processes was observed: at the costal site the ratio between non-sea-salt sulphate and methanesulphonic acid was higher, and the aerosol water soluble organic compounds were more oxidized than in the open ocean.

  2. High Concentration Standard Aerosol Generator.

    Science.gov (United States)

    1985-07-31

    materials. In addition to material problems, many liquids are extremely flammable or explosive when aerosolized. This can be checked by putting a small...Hochriner. D. (1975) Stub 3A 440-445. St6ber, W. Flachsbart, H. and Hochramn, D. (1970) Staub 3^, 277. Yoshida. H. Fujii, K. Yomimoto, Y. Masuda. H. and

  3. Aerosol Microphysics and Radiation Integration

    Science.gov (United States)

    2016-06-07

    1. REPORT DATE 30 SEP 2003 2. REPORT TYPE 3. DATES COVERED 00-00-2003 to 00-00-2003 4. TITLE AND SUBTITLE Aerosol Microphysics and Radiation...Airborne Radiometric Measurements.’ Bucholtz, A. (as member of CRYSTAL-FACE Science Team), NASA 2003 Group Achievement Award to CRYSTAL-FACE

  4. Climatic impacts of anthropogenic aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Iversen, T. [Oslo Univ. (Norway)

    1996-03-01

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

  5. Airborne Atmospheric Aerosol Measurement System

    Science.gov (United States)

    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).

  6. Aerosol and monsoon climate interactions over Asia: AEROSOL AND MONSOON CLIMATE INTERACTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhanqing [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Lau, W. K. -M. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Ramanathan, V. [Department of Atmospheric and Climate Sciences, University of California, San Diego California USA; Wu, G. [Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing China; Ding, Y. [National Climate Center, China Meteorological Administration, Beijing China; Manoj, M. G. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Liu, J. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Qian, Y. [Pacific Northwest National Laboratory, Richland Washington USA; Li, J. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Zhou, T. [Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing China; Fan, J. [Pacific Northwest National Laboratory, Richland Washington USA; Rosenfeld, D. [Institute of Earth Sciences, Hebrew University, Jerusalem Israel; Ming, Y. [Geophysical Fluid Dynamic Laboratory, NOAA, Princeton New Jersey USA; Wang, Y. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena California USA; Huang, J. [College of Atmospheric Sciences, Lanzhou University, Lanzhou China; Wang, B. [Department of Atmospheric Sciences, University of Hawaii, Honolulu Hawaii USA; School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing China; Xu, X. [Chinese Academy of Meteorological Sciences, Beijing China; Lee, S. -S. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Cribb, M. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Zhang, F. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Yang, X. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Zhao, C. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Takemura, T. [Research Institute for Applied Mechanics, Kyushu University, Fukuoka Japan; Wang, K. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Xia, X. [Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing China; Yin, Y. [School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing China; Zhang, H. [National Climate Center, China Meteorological Administration, Beijing China; Guo, J. [Chinese Academy of Meteorological Sciences, Beijing China; Zhai, P. M. [Chinese Academy of Meteorological Sciences, Beijing China; Sugimoto, N. [National Institute for Environmental Studies, Tsukuba Japan; Babu, S. S. [Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram India; Brasseur, G. P. [Max Planck Institute for Meteorology, Hamburg Germany

    2016-11-15

    Asian monsoons and aerosols have been studied extensively which are intertwined in influencing the climate of Asia. This paper provides a comprehensive review of ample studies on Asian aerosol, monsoon and their interactions. The region is the primary source of aerosol emissions of varies species, influenced by distinct weather and climatic regimes. On continental scale, aerosols reduce surface insolation and weaken the land-ocean thermal contrast, thus inhibiting the development of monsoons. Locally, aerosol radiative effects alter the thermodynamic stability and convective potential of the lower atmosphere leading to reduced temperatures, increased atmospheric stability, and weakened wind and atmospheric circulation. The atmospheric thermodynamic state may also be altered by the aerosol serving as cloud condensation nuclei or ice nuclei. Many mechanisms have been put forth regarding how aerosols modulate the amplitude, frequency, intensity, and phase of numerous monsoon climate variables. A wide range of theoretical, observational, and modeling findings on the Asian monsoon, aerosols, and their interactions are synthesized. A new paradigm is proposed on investigating aerosol-monsoon interactions, in which natural aerosols such as desert dust, black carbon from biomass burning, and biogenic aerosols from vegetation are considered integral components of an intrinsic aerosol-monsoon climate system, subject to external forcings of global warming, anthropogenic aerosols, and land use and change. Future research on aerosol-monsoon interactions calls for an integrated approach and international collaborations based on long-term sustained observations, process measurements, and improved models, as well as using observations to constrain model simulations and projections.

  7. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)

    Energy Technology Data Exchange (ETDEWEB)

    Zaveri, Rahul A.; Shaw, William J.; Cziczo, D. J.; Schmid, Beat; Ferrare, R.; Alexander, M. L.; Alexandrov, Mikhail; Alvarez, R. J.; Arnott, W. P.; Atkinson, D.; Baidar, Sunil; Banta, Robert M.; Barnard, James C.; Beranek, Josef; Berg, Larry K.; Brechtel, Fred J.; Brewer, W. A.; Cahill, John F.; Cairns, Brian; Cappa, Christopher D.; Chand, Duli; China, Swarup; Comstock, Jennifer M.; Dubey, Manvendra K.; Easter, Richard C.; Erickson, Matthew H.; Fast, Jerome D.; Floerchinger, Cody; Flowers, B. A.; Fortner, Edward; Gaffney, Jeffrey S.; Gilles, Mary K.; Gorkowski, K.; Gustafson, William I.; Gyawali, Madhu S.; Hair, John; Hardesty, Michael; Harworth, J. W.; Herndon, Scott C.; Hiranuma, Naruki; Hostetler, Chris A.; Hubbe, John M.; Jayne, J. T.; Jeong, H.; Jobson, Bertram T.; Kassianov, Evgueni I.; Kleinman, L. I.; Kluzek, Celine D.; Knighton, B.; Kolesar, K. R.; Kuang, Chongai; Kubatova, A.; Langford, A. O.; Laskin, Alexander; Laulainen, Nels S.; Marchbanks, R. D.; Mazzoleni, Claudio; Mei, F.; Moffet, Ryan C.; Nelson, Danny A.; Obland, Michael; Oetjen, Hilke; Onasch, Timothy B.; Ortega, Ivan; Ottaviani, M.; Pekour, Mikhail S.; Prather, Kimberly A.; Radney, J. G.; Rogers, Ray; Sandberg, S. P.; Sedlacek, Art; Senff, Christoph; Senum, Gunar; Setyan, Ari; Shilling, John E.; Shrivastava, ManishKumar B.; Song, Chen; Springston, S. R.; Subramanian, R.; Suski, Kaitlyn; Tomlinson, Jason M.; Volkamer, Rainer M.; Wallace, Hoyt A.; Wang, J.; Weickmann, A. M.; Worsnop, Douglas R.; Yu, Xiao-Ying; Zelenyuk, Alla; Zhang, Qi

    2012-08-22

    Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program's Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites - one within the Sacramento urban area and another about 40 km to the northeast in the foothills area - were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climate-related properties in freshly polluted and 'aged' urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: a) the scientific background and motivation for the study, b) the operational and logistical information pertinent to the execution of the study, c) an overview of key observations and initial results from the aircraft and ground-based sampling platforms, and d) a roadmap of

  8. Temporal Variability of Aerosol Properties during TCAP: Impact on Radiative Forcing

    Energy Technology Data Exchange (ETDEWEB)

    Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Berg, Larry K.; Fast, Jerome D.; Michalsky, Joseph J.; Lantz, K.; Hodges, G. B.

    2013-11-01

    Ground-based remote sensing and in situ observations of aerosol microphysical and optical properties have been collected during summertime (June-August, 2012) as part of the Two-Column Aerosol Project (TCAP; http://campaign.arm.gov/tcap/), which was supported by the U.S. Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) Program (http://www.arm.gov/). The overall goal of the TCAP field campaign is to study the evolution of optical and microphysical properties of atmospheric aerosol transported from North America to the Atlantic and their impact on the radiation energy budget. During TCAP, the ground-based ARM Mobile Facility (AMF) was deployed on Cape Cod, an arm-shaped peninsula situated on the easternmost portion of Massachusetts (along the east coast of the United States) and that is generally downwind of large metropolitan areas. The AMF site was equipped with numerous instruments for sampling aerosol, cloud and radiative properties, including a Multi-Filter Rotating Shadowband Radiometer (MFRSR), a Scanning Mobility Particle Sizer (SMPS), an Aerodynamic Particle Sizer (APS), and a three-wavelength nephelometer. In this study we present an analysis of diurnal and day-to-day variability of the column and near-surface aerosol properties obtained from remote sensing (MFRSR data) and ground-based in situ measurements (SMPS, APS, and nephelometer data). In particular, we show that the observed diurnal variability of the MFRSR aerosol optical depth is strong and comparable with that obtained previously from the AERONET climatology in Mexico City, which has a larger aerosol loading. Moreover, we illustrate how the variability of aerosol properties impacts the direct aerosol radiative forcing at different time scales.

  9. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES

    Directory of Open Access Journals (Sweden)

    R. A. Zaveri

    2012-08-01

    Full Text Available Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE Atmospheric Radiation Measurement (ARM program's Carbonaceous Aerosol and Radiative Effects Study (CARES carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites – one within the Sacramento urban area and another about 40 km to the northeast in the foothills area – were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climate-related properties in freshly polluted and "aged" urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: (a the scientific background and motivation for the study, (b the operational and logistical information pertinent to the execution of the study, (c an overview of key observations and initial findings from the aircraft and ground-based sampling platforms, and (d a roadmap

  10. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES

    Directory of Open Access Journals (Sweden)

    R. A. Zaveri

    2012-01-01

    Full Text Available Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE Atmospheric Radiation Measurement (ARM program's Carbonaceous Aerosol and Radiative Effects Study (CARES carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites – one within the Sacramento urban area and another about 40 km to the northeast in the foothills area – were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climate-related properties in freshly polluted and "aged" urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: (a the scientific background and motivation for the study, (b the operational and logistical information pertinent to the execution of the study, (c an overview of key observations and initial results from the aircraft and ground-based sampling platforms, and (d a roadmap

  11. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)

    Science.gov (United States)

    Zaveri, R. A.; Shaw, W. J.; Cziczo, D. J.; Schmid, B.; Ferrare, R. A.; Alexander, M. L.; Alexandrov, M.; Alvarez, R. J.; Arnott, W. P.; Atkinson, D. B.; Baidar, S.; Banta, R. M.; Barnard, J. C.; Beranek, J.; Berg, L. K.; Brechtel, F.; Brewer, W. A.; Cahill, J. F.; Cairns, B.; Cappa, C. D.; Chand, D.; China, S.; Comstock, J. M.; Dubey, M. K.; Easter, R. C.; Erickson, M. H.; Fast, J. D.; Floerchinger, C.; Flowers, B. A.; Fortner, E.; Gaffney, J. S.; Gilles, M. K.; Gorkowski, K.; Gustafson, W. I.; Gyawali, M.; Hair, J.; Hardesty, R. M.; Harworth, J. W.; Herndon, S.; Hiranuma, N.; Hostetler, C.; Hubbe, J. M.; Jayne, J. T.; Jeong, H.; Jobson, B. T.; Kassianov, E. I.; Kleinman, L. I.; Kluzek, C.; Knighton, B.; Kolesar, K. R.; Kuang, C.; Kubátová, A.; Langford, A. O.; Laskin, A.; Laulainen, N.; Marchbanks, R. D.; Mazzoleni, C.; Mei, F.; Moffet, R. C.; Nelson, D.; Obland, M. D.; Oetjen, H.; Onasch, T. B.; Ortega, I.; Ottaviani, M.; Pekour, M.; Prather, K. A.; Radney, J. G.; Rogers, R. R.; Sandberg, S. P.; Sedlacek, A.; Senff, C. J.; Senum, G.; Setyan, A.; Shilling, J. E.; Shrivastava, M.; Song, C.; Springston, S. R.; Subramanian, R.; Suski, K.; Tomlinson, J.; Volkamer, R.; Wallace, H. W.; Wang, J.; Weickmann, A. M.; Worsnop, D. R.; Yu, X.-Y.; Zelenyuk, A.; Zhang, Q.

    2012-08-01

    Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program's Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites - one within the Sacramento urban area and another about 40 km to the northeast in the foothills area - were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climate-related properties in freshly polluted and "aged" urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: (a) the scientific background and motivation for the study, (b) the operational and logistical information pertinent to the execution of the study, (c) an overview of key observations and initial findings from the aircraft and ground-based sampling platforms, and (d) a roadmap of planned data

  12. Characterizing the impact of urban emissions on regional aerosol particles; airborne measurements during the MEGAPOLI experiment

    Directory of Open Access Journals (Sweden)

    E. J. Freney

    2013-09-01

    Full Text Available The MEGAPOLI experiment took place in July 2009. The aim of this campaign was to study the aging and reactions of aerosol and gas-phase emissions in the city of Paris. Three ground-based measurement sites and several mobile platforms including instrument equipped vehicles and the ATR-42 aircraft were involved. We present here the variations in particle- and gas-phase species over the city of Paris using a combination of high-time resolution measurements aboard the ATR-42 aircraft. Particle chemical composition was measured using a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS giving detailed information of the non-refractory submicron aerosol species. The mass concentration of BC, measured by a particle absorption soot photometer (PSAP, was used as a marker to identify the urban pollution plume boundaries. Aerosol mass concentrations and composition were affected by air-mass history, with air masses that spent longest time over land having highest fractions of organic aerosol and higher total mass concentrations. The Paris plume is mainly composed of organic aerosol (OA, black carbon and nitrate aerosol, as well as high concentrations of anthropogenic gas-phase species such as toluene, benzene, and NOx. Using BC and CO as tracers for air-mass dilution, we observe the ratio of ΔOA / ΔBC and ΔOA / ΔCO increase with increasing photochemical age (−log(NOx / NOy. Plotting the equivalent ratios for the Positive Matrix Factorization (PMF resolved species (LV-OOA, SV-OOA, and HOA illustrate that the increase in OA is a result of secondary organic aerosol (SOA. Within Paris the changes in the ΔOA / ΔCO are similar to those observed during other studies in Mexico city, Mexico and in New England, USA. Using the measured VOCs species together with recent organic aerosol formation yields we predicted ~ 50% of the measured organics. These airborne measurements during the MEGAPOLI experiment show that urban emissions contribute to the

  13. Ratios of Normal Variables

    Directory of Open Access Journals (Sweden)

    George Marsaglia

    2006-05-01

    Full Text Available This article extends and amplifies on results from a paper of over forty years ago. It provides software for evaluating the density and distribution functions of the ratio z/w for any two jointly normal variates z,w, and provides details on methods for transforming a general ratio z/w into a standard form, (a+x/(b+y , with x and y independent standard normal and a, b non-negative constants. It discusses handling general ratios when, in theory, none of the moments exist yet practical considerations suggest there should be approximations whose adequacy can be verified by means of the included software. These approximations show that many of the ratios of normal variates encountered in practice can themselves be taken as normally distributed. A practical rule is developed: If a < 2.256 and 4 < b then the ratio (a+x/(b+y is itself approximately normally distributed with mean μ = a/(1.01b − .2713 and variance 2 = (a2 + 1/(b2 + .108b − 3.795 − μ2.

  14. Ratios of Normal Variables

    Directory of Open Access Journals (Sweden)

    George Marsaglia

    2006-05-01

    Full Text Available This article extends and amplifies on results from a paper of over forty years ago. It provides software for evaluating the density and distribution functions of the ratio z/w for any two jointly normal variates z,w, and provides details on methods for transforming a general ratio z/w into a standard form, (a+x/(b+y , with x and y independent standard normal and a, b non-negative constants. It discusses handling general ratios when, in theory, none of the moments exist yet practical considerations suggest there should be approximations whose adequacy can be verified by means of the included software. These approximations show that many of the ratios of normal variates encountered in practice can themselves be taken as normally distributed. A practical rule is developed: If a < 2.256 and 4 < b then the ratio (a+x/(b+y is itself approximately normally distributed with mean μ = a/(1.01b - .2713 and variance σ2 = (a2 + 1/(b2 + .108b - 3.795 μ2.

  15. Coupling aerosol-cloud-radiative processes in the WRF-Chem model: investigating the radiative impact of elevated point sources

    Directory of Open Access Journals (Sweden)

    E. G. Chapman

    2008-08-01

    Full Text Available The local and regional influence of elevated point sources on summertime aerosol forcing and cloud-aerosol interactions in northeastern North America was investigated using the WRF-Chem community model. The direct effects of aerosols on incoming solar radiation were simulated using existing modules to relate aerosol sizes and chemical composition to aerosol optical properties. Indirect effects were simulated by adding a prognostic treatment of cloud droplet number and adding modules that activate aerosol particles to form cloud droplets, simulate aqueous-phase chemistry, and tie a two-moment treatment of cloud water (cloud water mass and cloud droplet number to an existing radiation scheme. Fully interactive feedbacks thus were created within the modified model, with aerosols affecting cloud droplet number and cloud radiative properties, and clouds altering aerosol size and composition via aqueous processes, wet scavenging, and gas-phase-related photolytic processes. Comparisons of a baseline simulation with observations show that the model captured the general temporal cycle of aerosol optical depths (AODs and produced clouds of comparable thickness to observations at approximately the proper times and places. The model overpredicted SO2 mixing ratios and PM2.5 mass, but reproduced the range of observed SO2 to sulfate aerosol ratios, suggesting that atmospheric oxidation processes leading to aerosol sulfate formation are captured in the model. The baseline simulation was compared to a sensitivity simulation in which all emissions at model levels above the surface layer were set to zero, thus removing stack emissions. Instantaneous, site-specific differences for aerosol and cloud related properties between the two simulations could be quite large, as removing above-surface emission sources influenced when and where clouds formed within the modeling domain. When summed spatially over the finest resolution model

  16. Environmental research program: FY 1987, annual report

    Energy Technology Data Exchange (ETDEWEB)

    1988-03-01

    This multidisciplinary research program includes fundamental and applied research in physics, chemistry, engineering, and biology, as well as research on the development of advanced methods of measurement and analysis. The Program's Annual Report contains summaries of research performed during FY 1987 in the areas of atmospheric aerosols, flue gas chemistry, combustion, membrane bioenergetics, and analytical chemistry. The main research interests of the Atmospheric Aerosol Research group concern the chemical and physical processes that occur in haze, clouds, and fogs. For their studies, the group is developing novel analytical and research methods for characterizing aerosol species. Aerosol research is performed in the laboratory and in the field. Studies of smoke emissions from fires and their possible effects on climatic change, especially as related to nuclear winter, are an example of the collaboration between the Atmospheric Aerosol Research and Combustion Research Groups.

  17. Study of the effect of different type of aerosols on UV-B radiation from measurements during EARLINET

    Directory of Open Access Journals (Sweden)

    D. S. Balis

    2003-09-01

    Full Text Available Routine lidar measurements of the vertical distribution of the aerosol extinction coefficient and the extinction-to-backscatter ratio have been performed at Thessaloniki, Greece using a Raman lidar system in the frame of the EARLINET project since 2000. Spectral and broadband UV-B irradiance measurements, as well as total ozone observations, were available whenever lidar measurements were obtained. From the available measurements several cases could be identified that allowed the study of the effect of different types of aerosol on the levels of the UV-B solar irradiance at the Earth's surface. The TUV radiative transfer model has been used to simulate the irradiance measurements, using total ozone and the lidar aerosol data as input. From the comparison of the model results with the measured spectra the effective single scattering albedo was determined using an iterative procedure, which has been verified against results from the 1998 Lindenberg Aerosol Characterization Experiment. It is shown that the same aerosol optical depth and same total ozone values can show differences up to 10% in the UV-B irradiance at the Earth's surface, which can be attributed to differences in the aerosol type. It is shown that the combined use of the estimated single scattering albedo and the measured extinction-to-backscatter ratio leads to a better characterization of the aerosol type probed.

  18. Study of the effect of different type of aerosols on UV-B radiation from measurements during EARLINET

    Directory of Open Access Journals (Sweden)

    D. S. Balis

    2004-01-01

    Full Text Available Routine lidar measurements of the vertical distribution of the aerosol extinction coefficient and the extinction-to-backscatter ratio have been performed at Thessaloniki, Greece using a Raman lidar system in the frame of the EARLINET project since 2000. Co-located spectral and broadband solar UV-B irradiance measurements, as well as total ozone observations, were available whenever lidar measurements were obtained. From the available measurements several cases could be identified that allowed the study of the effect of different types of aerosol on the levels of the UV-B solar irradiance at the Earth's surface. The TUV radiative transfer model has been used to simulate the irradiance measurements, using total ozone and the lidar aerosol data as input. From the comparison of the model results with the measured spectra the effective single scattering albedo was determined using an iterative procedure, which has been verified against results from the 1998 Lindenberg Aerosol Characterization Experiment. It is shown that for the same aerosol optical depth and for the same total ozone values the UV-B irradiances at the Earth's surface can show differences up to 10%, which can be attributed to differences in the aerosol type. It is shown that the combined use of the estimated single scattering albedo and of the measured extinction-to-backscatter ratio leads to a better characterization of the aerosol type probed.

  19. Field and Laboratory Studies of Atmospheric Organic Aerosol

    Science.gov (United States)

    Coggon, Matthew Mitchell

    these conditions to all measurements conducted during E-PEACE demonstrated that a large fraction of cloud droplet (72%) and dry aerosol mass (12%) sampled in the California coastal study region was heavily or moderately influenced by ship emissions. Another study investigated the chemical and physical evolution of a controlled organic plume emitted from the R/V Point Sur. Under sunny conditions, nucleated particles composed of oxidized organic compounds contributed nearly an order of magnitude more cloud condensation nuclei (CCN) than less oxidized particles formed under cloudy conditions. The processing time necessary for particles to become CCN active was short ( 4 hr). Laboratory chamber experiments were also conducted to evaluate particle-phase processes influencing aerosol phase and composition. In one study, ammonium sulfate seed was coated with a layer of secondary organic aerosol (SOA) from toluene oxidation followed by a layer of SOA from α-pinene oxidation. The system exhibited different evaporative properties than ammonium sulfate seed initially coated with α-pinene SOA followed by a layer of toluene SOA. This behavior is consistent with a shell-and-core model and suggests limited mixing among different SOA types. Another study investigated the reactive uptake of isoprene epoxy diols (IEPOX) onto non-acidified aerosol. It was demonstrated that particle acidity has limited influence on organic aerosol formation onto ammonium sulfate seed, and that the chemical system is limited by the availability of nucleophiles such as sulfate. Flow tube experiments were conducted to examine the role of iron in the reactive uptake and chemical oxidation of glycolaldehyde. Aerosol particles doped with iron and hydrogen peroxide were mixed with gas-phase glycolaldehyde and photochemically aged in a custom-built flow reactor. Compared to particles free of iron, iron-doped aerosols significantly enhanced the oxygen to carbon (O/C) ratio of accumulated organic mass. The primary

  20. Overview of the Megacity Aerosol Experiment: Mexico City (MAX-Mex)

    Science.gov (United States)

    Gaffney, J. S.

    2007-05-01

    Tropospheric aerosols can play an important role the radiative balance of the globe. This is due to their ability to scatter and absorb solar radiation. The sign of this forcing will depend on their chemical composition and size, their lifetimes, and position in the atmosphere. Major sources of aerosols are now coming from megacities: Cities with more than 10 million population. As part of the MILAGRO campaign, the Megacity Aerosol Experiment: Mexico City was conducted by the Atmospheric Science Program of the Climate Change Research Division of the Department of Energy in collaboration with the scientists supported by NSF, NASA, and Mexican agencies. The preliminary results of the study will be overviewed and highlights of the efforts from both ground based and airborne measurements presented. Data from the study confirm that the megacity plumes are significant sources of both primary and secondary aerosols into the regional scale, and black carbon and secondary aerosols are contributing to single scattering albedos in the Valley of Mexico and downwind that are substantially reduced when compared to other areas (such as the eastern United States). The potential of biomass burning as well as megacity plumes contributing to a decrease in the aerosol single scattering albedos (aerosol direct effects) on regional scales will be discussed. This work was performed as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City under the support of the Atmospheric Science Program. "This researchwas supported by the Office of Science (BER), U. S. Department of Energy, Grant No. DE-FG02-07ER64328.

  1. MODELING OF ORGANIC CARBON AEROSOL DISTRIBUTIONS OVER EAST ASIA IN THE SPRINGTIME

    Institute of Scientific and Technical Information of China (English)

    Meigen Zhang

    2004-01-01

    The Models-3 Community Multi-scale Air Quality (CMAQ) modeling system coupled with the Regional Atmospheric Modeling System (RAMS) is applied to East Asia to investigate the transport and evolution processes of organic carbon (OC) aerosols in the springtime of 2001. The simulated OC mixing ratios are compared with ground level observations at three remote sites in Japan during the Aerosol Characterization Experiment - Asia (ACE-Asia) field campaign. It is found that the modeled OC concentrations are generally in good agreement with the observed ones, and the model reproduces the time variations in OC mixing ratios reasonably well. Model results show that high levels (larger than 16 mg.m-2) of column burden of OC aerosols concentrated in the middle reaches of Yangtse River and southern isopleth of 4 mg.m-2 extended to the inner area of northwestern Pacific Ocean.

  2. Aerosol characterization study using multi-spectrum remote sensing measurement techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Glen, Crystal Chanea; Sanchez, Andres L.; Lucero, Gabriel Anthony; Schmitt, Randal L.; Johnson, Mark S.; Tezak, Matthew S; Servantes, Brandon Lee

    2013-09-01

    A unique aerosol flow chamber coupled with a bistatic LIDAR system was implemented to measure the optical scattering cross sections and depolarization ratio of common atmospheric particulates. Each of seven particle types (ammonium sulfate, ammonium nitrate, sodium chloride, potassium chloride, black carbon and Arizona road dust) was aged by three anthropogenically relevant mechanisms: 1. Sulfuric acid deposition, 2. Toluene ozonolysis reactions, and 3. m-Xylene ozonolysis reactions. The results of pure particle scattering properties were compared with their aged equivalents. Results show that as most particles age under industrial plume conditions, their scattering cross sections are similar to pure black carbon, which has significant impacts to our understanding of aerosol impacts on climate. In addition, evidence emerges that suggest chloride-containing aerosols are chemically altered during the organic aging process. Here we present the direct measured scattering cross section and depolarization ratios for pure and aged atmospheric particulates.

  3. Spatial variation of chemical composition and sources of submicron aerosol in Zurich: factor analysis of mobile aerosol mass spectrometer data

    Directory of Open Access Journals (Sweden)

    C. Mohr

    2011-04-01

    Full Text Available Mobile measurements of PM1 (PM with an aerodynamic diameter D<1 μm chemical composition using a quadrupole aerosol mass spectrometer and a multi-angle absorption photometer were performed using the PSI mobile laboratory during winter 2007/2008 and December 2008 in the metropolitan area of Zurich, Switzerland. Positive matrix factorization (PMF applied to the organic fraction of PM1 yielded 3 factors: Hydrocarbon-like organic aerosol (HOA related to traffic emissions; organic aerosol from wood burning for domestic heating purposes (WBOA; and oxygenated organic aerosol (OOA, assigned to secondary organic aerosol formed by oxidation of volatile precursors. The spatial variation of the chemical composition of PM1 shows a uniform distribution throughout the city: for primary emissions, road traffic is important along major roads (varying between 7 and 14% of PM1 for different sites within the city, but overall, domestic wood burning is more important for the organic aerosol concentrations in Zurich during winter time (varying between 8–15% of PM1 for different sites within the city. OOA makes up the largest fraction of organic aerosol (44% on average. A new method, based on simultaneous on-road mobile and stationary background measurements and using the ratio of on-road sulfate to stationary sulfate to correct for small-scale dynamic effects, allows for the separation of PM1 emitted or produced locally and the PM1 from the regional background. It could be shown that especially during thermal inversions over the Swiss plateau, regional background concentrations contribute substantially to particulate number concentrations (60% on average as well as to the concentrations of PM1 components (on average 60% for black carbon and HOA, over 97% for WBOA and OOA, and more than 94% for the measured inorganic components in downtown Zurich. The results emphasize, on

  4. Source apportionment of ambient aerosol applying PMF on AMS mobile and stationary data

    Science.gov (United States)

    Mohr, C.; Weimer, S.; Richter, R.; Decarlo, P. F.; Chirico, R.; Heringa, M. F.; Prévôt, A. S. H.; Baltensperger, U.

    2009-04-01

    organic mass. Oxygenated organic aerosol (OOA), most of which is secondary, represents the remaining fraction. At the background site, the measured aerosol composition is more strongly influenced by secondary species, since this site is less exposed to primary emissions. The relative OOA contribution is higher than on-road, as well are particulate sulphate, nitrate, and ammonium contributions. Calculations of particulate sulphate ratios suggest that differences in absolute background and on-road concentration levels are mostly due to meteorological transport processes, but local emissions play a major role. Additional PMF analysis of AMS data from other regions and recent mobile AMS measurements will also be presented. Alfarra, M. R., et al. (2007). Environ. Sci. Technol., 41: 5770 - 5777. Canagaratna, M. R., et al. (2007). Mass Spectrom. Rev. , 26: 185-222. Lanz, V. A., et al. (2007). Atmos. Chem. Phys., 7: 1503-1522.

  5. Uncertainties in global aerosols and climate effects due to biofuel emissions

    Directory of Open Access Journals (Sweden)

    J. K. Kodros

    2015-04-01

    effects is unclear due to uncertainties in model inputs. This uncertainty limits our ability to introduce mitigation strategies aimed at reducing biofuel black carbon emissions in order to counter warming effects from greenhouse-gases. To better understand the climate impact of particle emissions from biofuel combustion, we recommend field/laboratory measurements to narrow constraints on: (1 emissions mass, (2 emission size distribution, (3 mixing state, and (4 ratio of black carbon to organic aerosol.

  6. Organic compounds present in the natural Amazonian aerosol: Characterization by gas chromatography-mass spectrometry

    Science.gov (United States)

    Graham, Bim; Guyon, Pascal; Taylor, Philip E.; Artaxo, Paulo; Maenhaut, Willy; Glovsky, M. Michael; Flagan, Richard C.; Andreae, Meinrat O.

    2003-12-01

    burning, were detected only at low levels in the fine aerosol samples. On the basis of the levoglucosan-to-OC emission ratio measured for biomass burning aerosol, we estimate that an average of ˜16% of the OC in the fine aerosol was due to biomass burning during CLAIRE 2001, indicating that the major fraction was associated with biogenic particles.

  7. Observation-constrained Estimation of Aerosol Climate Impacts over S Asia

    Science.gov (United States)

    Feng, Y.; Kotamarthi, V. R.; Jefferson, A.; Wilcox, E. M.; Bender, F.; Pistone, K.; Praveen, P. S.; Thomas, R. M.; Ramanathan, V.

    2012-12-01

    Climate impacts of elevated aerosols over S. Asia have been studied extensively. Despite different methods employed and uncertainties, one clear message is that these aerosols have a large impact on the regional energy balance. However, uncertainty in the elevated aerosol absorption, as well as poor fidelity in model representations of aerosol-cloud interactions contribute to the discrepancies in quantifying the aerosol influences on monsoon circulation and rainfall. The main goal of this study is to examine the latitudinal heating gradient and the aerosol impact on the hydrological cycle during the pre-monsoon, with observational constraints on the aerosol vertical distribution. We run a 12-km regional climate model (WRF-Chem) driven by the NCEP analysis data from August 2011 to March 2012. During this time period, the ground-based profiling of aerosol extinction, cloud liquid water, water vapor, and temperature were taken at Nainital (29.38°N, 79.45°E) as part of the Ganges Valley Experiment (GVAX). It is the first time that such vertical profiling data sets are available in the northern Indian subcontinent for such a long period. In the pre-monsoon season (Feb-Mar), the regional model simulations show good agreement in the aerosol optical depth (AOD; 0.1~0.2) and black carbon (BC; ~0.8 ug/m3) concentrations compared with the surface observations at Nainital. The observed diurnal variation in BC concentration, peaking in the afternoon and lowering at night, is also captured by the model as a result of the thermal convection from the polluted valley. The simulated OC/BC ratio is about 2~4 near the surface, which is lower than observations, implying that we may underestimate the secondary organic formation from the biomass burning or biogenic sources. Spectral measurements of aerosol absorption will be used to investigate the absorption of OC in the UV and visible bands. During this time, surface and in situ profiling of aerosols and clouds were also made during

  8. Carbonaceous aerosols in Norwegian urban areas

    Directory of Open Access Journals (Sweden)

    K. E. Yttri

    2009-03-01

    Full Text Available Little is known regarding levels and source strength of carbonaceous aerosols in Scandinavia. In the present study, ambient aerosol (PM10 and PM2.5 concentrations of elemental carbon (EC, organic carbon (OC, water-insoluble organic carbon (WINSOC, and water-soluble organic carbon (WSOC are reported for a curbside site, an urban background site, and a suburban site in Norway in order to investigate their spatial and seasonal variations. Aerosol filter samples were collected using tandem filter sampling to correct for the positive sampling artefact introduced by volatile and semivolatile OC. Analyses were performed using the thermal optical transmission (TOT instrument from Sunset Lab Inc., which corrects for charring during analysis. Finally, we estimated the relative contribution of OC from wood burning based on the samples content of levoglucosan.

    Levels of EC varied by more than one order of magnitude between sites, likely due to the higher impact of vehicular traffic at the curbside and the urban background sites. In winter, the level of particulate organic carbon (OCp at the suburban site was equal to (for PM10 or even higher (for PM2.5 than the levels observed at the curbside and the urban background sites. This finding was attributed to the impact of residential wood burning at the suburban site in winter, which was confirmed by a high mean concentration of levoglucosan (407 ng m−3. This finding indicates that exposure to primary combustion derived OCp could be equally high in residential areas as in a city center. It is demonstrated that OCp from wood burning (OCwood accounted for almost all OCp at the suburban site in winter, allowing a new estimate of the ratio TCp/levoglucosan for both PM10 and PM2.5. Particulate carbonaceous material (PCM

  9. Fast airborne aerosol size and chemistry measurements with the high resolution aerosol mass spectrometer during the MILAGRO Campaign

    Science.gov (United States)

    Decarlo, P. F.; Dunlea, E. J.; Kimmel, J. R.; Aiken, A. C.; Sueper, D.; Crounse, J.; Wennberg, P. O.; Emmons, L.; Shinozuka, Y.; Clarke, A.; Zhou, J.; Tomlinson, J.; Collins, D. R.; Knapp, D.; Weinheimer, A. J.; Montzka, D. D.; Campos, T.; Jimenez, J. L.

    2007-12-01

    The concentration, size, and composition of non-refractory submicron aerosol (NR-PM1) was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS, in which the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA) species dominate the NR-PM1 mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA) and biomass burning (BB) are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 μg m-3 (STP) ppm-1. This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006) and Kleinman et al. (2007b). BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance of nitrate decreases with distance from the city likely due to evaporation. BB does not appear to be a strong source of nitrate despite its high emissions of nitrogen oxides, presumably due to low ammonia

  10. Fast airborne aerosol size and chemistry measurements with the high resolution aerosol mass spectrometer during the MILAGRO Campaign

    Directory of Open Access Journals (Sweden)

    P. F. DeCarlo

    2007-12-01

    Full Text Available The concentration, size, and composition of non-refractory submicron aerosol (NR-PM1 was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS, in which the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA species dominate the NR-PM1 mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA and biomass burning (BB are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 μg m−3 (STP ppm−1. This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006 and Kleinman et al. (2007b. BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance of nitrate decreases with distance from the city likely due to evaporation. BB does not appear to be a strong source of nitrate

  11. Fast Airborne Aerosol Size and Chemistry Measurements with the High Resolution Aerosol Mass Spectrometer during the MILAGRO Campaign

    Science.gov (United States)

    DeCarlo, P. F.; Dunlea, E. J.; Kimmel, J. R.; Aiken, A. C.; Sueper, D.; Crounse, J.; Wennberg, P. O.; Emmons, L.; Shinozuka, Y.; Clarke, A.; Zhou, J.; Tomlinson, J.; Collins,D. R.; Knapp, D.; Weinheimer, A. J.; Montzka,D. D.; Campos,T.; Jimenez, J. L.

    2007-01-01

    The concentration, size, and composition of non-refractory submicron aerosol (NR-PM(sub l)) was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS. During the campaign the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA) species dominate the NR-PM(sub l) mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA) and biomass burning (BB) are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 microg/cubic m (STP) ppm(exp -1). This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006) and Kleinman et al. (2008). The stability of the OA/CO while O/C increases with photochemical age implies a net loss of carbon from the OA. BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major regional source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance of nitrate decreases with distance from the city

  12. Measurements of Natural Radioactivity in Submicron Aerosols in Mexico City.

    Science.gov (United States)

    Gaffney, J. S.; Marley, N. A.; Sterling, K.; Sturchio, N. C.

    2003-12-01

    Natural radionuclides can be useful in evaluating the transport of ozone and aerosols in the troposphere. Beryllium-7, which is produced by cosmic ray interactions in the upper troposphere and lower stratosphere and becomes adsorbed on fine aerosols, can be a useful indicator of upper air transport into a region. Lead-210 is produced by the decay of radon-222 out-gassed into the lower atmosphere from ground-based uranium deposits. Potassium-40, found in soils, can act as a measure of wind-blown dust and also comes from burning of wood and other biomass that is enriched in this natural radioisotope. Thus, both lead-210 and potassium-40 can aid in identification of aerosols sourced in the lower atmosphere. As part of our continuing interest in the lifetimes and sources of aerosols and their radiative effects, we report here measurements of fine aerosol radioactivity in Mexico City, one of the largest megacities in the world. Samples were collected on quartz fiber filters by using cascade impactors (Sierra type, Anderson Instruments) and high-volume air samplers from the rooftop of the main laboratory of El Centro Nacional de Investigacion y Capacitacion Ambiental (CENICA). By using stage 4 of the impactor and timers, we were able to collect integrated samples of sizes > 1 micrometer and < 1 micrometer over 12-hr time periods daily for approximately one month in April 2003. Samples were counted at the University of Illinois at Chicago by using state-of-the-art gamma counting (beryllium-7, 477.6 keV; potassium-40, 1460.8 keV; lead-210, 46.5 keV). The beryllium-7 data indicate one possible upper-air transport event during April 2003. As expected, the lead-210 data indicate very little soil contribution to the fine aerosol. The potassium-40 data showed an increase in fine aerosol potassium during Holy Week that might be attributed to local combustion of biomass fuels. The data will be presented and discussed in light of future data analysis and comparison with other

  13. Large differences in aerosol optical properties over the north-west Atlantic Ocean during the TCAP field campaign

    Science.gov (United States)

    Chand, D.; Berg, L. K.; Comstock, J. M.; Fast, J. D.; Flynn, C. J.; Hubbe, J. M.; Kassianov, E.; Mei, F.; Pekour, M. S.; Schmid, B.; Sedlacek, A. J., III; Tomlinson, J. M.; Shilling, J. E.; Wilson, J. M.; Zelenyuk, A.; Berkowitz, C. M.

    2014-12-01

    Aerosol radiative forcing is an important parameter in the Earth's radiation budget and can be an important driver of atmospheric circulation and the hydrological cycle. Accurate estimation of aerosol radiative forcing requires measurement of both the extensive and intensive optical properties of aerosols. While the intensive optical properties are independent of aerosol mass or number, they are critical inputs when calculating radiative forcing with applications to climate research, satellite remote sensing and model validations. The key aerosol intensive properties that need to be evaluated include single scattering albedo (SSA), the angstrom exponent, the asymmetry parameter, the radiative forcing efficiency, and the hygroscopic scattering factor. We report here on values of these variables over the Cape Cod and nearby northwest Atlantic Ocean during the Two Column Aerosol Project (TCAP). The average SSA shows a distinct profile having higher SSA values below the top of well-mixed residual layer (RL) and lower SSA above it. Aerosol in the free troposphere (FT) were found to have less spectral dependence in their optical properties, lower back scatter fraction and higher hygroscopic growth relative to aerosols found in the RL. Analysis of individual particle composition suggests that that ratio of aged to fresh aerosol numbers in the FT is 70% higher compared to aerosols measured in the RL, and that smoke from biomass burning contributed ~10% to this number. Single particle analysis also reveals that the fraction and variability of coated black carbon (BC) aerosol is higher in the FT relative to that measured in the residual layer. The daily radiative forcing efficiency of these aerosols in the FT is factor 2 higher than below RL. Seven years (2007-2013) of CALIPSO satellite observations show that the mean altitude of the top of smoke layers (~3.3 km) consistent with these in situ observations from TCAP. Overall, the long term CALIPSO observations characterizes

  14. Aerosol classification by airborne high spectral resolution lidar observations

    Directory of Open Access Journals (Sweden)

    S. Groß

    2012-10-01

    Full Text Available During four aircraft field experiments with the DLR research aircraft Falcon in 1998 (LACE, 2006 (SAMUM-1 and 2008 (SAMUM-2 and EUCAARI, airborne High Spectral Resolution Lidar (HSRL and in situ measurements of aerosol microphysical and optical properties were performed. Altogether, the properties of six different aerosol types and aerosol mixtures – Saharan mineral dust, Saharan dust mixtures, Canadian biomass burning aerosol, African biomass burning aerosol, anthropogenic pollution aerosol, and marine aerosol have been studied. On the basis of this extensive HSRL data set, we present an aerosol classification scheme which is also capable to identify mixtures of different aerosol types. We calculated mixing lines that allowed us to determine the contributing aerosol types. The aerosol classification scheme was validated with in-situ measurements and backward trajectory analyses. Our results demonstrate that the developed aerosol mask is capable to identify complex stratifications with different aerosol types throughout the atmosphere.

  15. Multi-year satellite and surface observations of AOD in support of two-column aerosol project (TCAP) field campaign

    Science.gov (United States)

    Kassianov, Evgueni; Chand, Duli; Berg, Larry; Fast, Jerome; Tomlinson, Jason; Ferrare, Richard; Hostetler, Chris; Hair, John

    2012-11-01

    We use combined multi-year measurements from the surface and space for assessing the spatial and temporal distribution of aerosol properties within a large (~400x400 km) region centered on Cape Cod, Massachusetts, along the East Coast of the United States. The ground-based Aerosol Robotic Network (AERONET) measurements at Martha's Vineyard Coastal Observatory (MVCO) site and Moderate Resolution Imaging Spectrometer (MODIS) sensors on board the Terra and Aqua satellites provide horizontal and temporal variations of aerosol optical depth, while the Cloud- Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) offers the altitudes of aerosol-layers. The combined ground-based and satellite measurements indicated several interesting features among which were the large differences in the aerosol properties observed in July and February. We applied the climatology of aerosol properties for designing the Two-Column Aerosol Project (TCAP), which is supported by the U.S. Department of Energy's (DOE's) Atmospheric Radiation Measurement (ARM) Program. The TCAP field campaign involves 12-month deployment (started July 1, 2012) of the ground-based ARM Mobile Facility (AMF) and Mobile Aerosol Observing System (MAOS) on Cape Cod and complimentary aerosol observations from two research aircraft: the DOE Gulfstream-1 (G-1) and the National Aeronautics and Space Administration (NASA) B200 King Air. Using results from the coordinated G-1 and B200 flights during the recent (July, 2012) Intensive Observation Period, we demonstrated that the G-1 in situ measurements and B200 active remote sensing can provide complementary information on the temporal and spatial changes of the aerosol properties off the coast of North America.

  16. Effect of ethanol as a co-solvent on the aerosol performance and stability of spray-dried lysozyme

    DEFF Research Database (Denmark)

    Ji, Shuying; Thulstrup, Peter Waaben; Mu, Huiling

    2016-01-01

    -solvent on the stability and aerosol performance of spray-dried protein. Lysozyme was dissolved in solutions with various ratios of ethanol and water, and subsequently spray-dried. A change from spherical particles into wrinkled and folded particles was observed upon increasing the ratio of ethanol in the feed...

  17. The rectilinear Steiner ratio

    Directory of Open Access Journals (Sweden)

    PO de Wet

    2005-06-01

    Full Text Available The rectilinear Steiner ratio was shown to be 3/2 by Hwang [Hwang FK, 1976, On Steiner minimal trees with rectilinear distance, SIAM Journal on Applied Mathematics, 30, pp. 104– 114.]. We use continuity and introduce restricted point sets to obtain an alternative, short and self-contained proof of this result.

  18. Gender Ratio in Dyslexia.

    Science.gov (United States)

    Miles, T. R.; Haslum, M. N.; Wheeler, T. J.

    1998-01-01

    A study involving 11,804 British children (age 10) found that when specified criteria for dyslexia were used, 269 children qualified as dyslexic. These included 223 boys and 46 girls, for a ratio of 4.51 to 1. Difficulties in interpreting these data are discussed and a defense of the criteria is provided. (Author/CR)

  19. Aerosol and monsoon climate interactions over Asia

    Science.gov (United States)

    Li, Zhanqing; Lau, W. K.-M.; Ramanathan, V.; Wu, G.; Ding, Y.; Manoj, M. G.; Liu, J.; Qian, Y.; Li, J.; Zhou, T.; Fan, J.; Rosenfeld, D.; Ming, Y.; Wang, Y.; Huang, J.; Wang, B.; Xu, X.; Lee, S.-S.; Cribb, M.; Zhang, F.; Yang, X.; Zhao, C.; Takemura, T.; Wang, K.; Xia, X.; Yin, Y.; Zhang, H.; Guo, J.; Zhai, P. M.; Sugimoto, N.; Babu, S. S.; Brasseur, G. P.

    2016-12-01

    The increasing severity of droughts/floods and worsening air quality from increasing aerosols in Asia monsoon regions are the two gravest threats facing over 60% of the world population living in Asian monsoon regions. These dual threats have fueled a large body of research in the last decade on the roles of aerosols in impacting Asian monsoon weather and climate. This paper provides a comprehensive review of studies on Asian aerosols, monsoons, and their interactions. The Asian monsoon region is a primary source of emissions of diverse species of aerosols from both anthropogenic and natural origins. The distributions of aerosol loading are strongly influenced by distinct weather and climatic regimes, which are, in turn, modulated by aerosol effects. On a continental scale, aerosols reduce surface insolation and weaken the land-ocean thermal contrast, thus inhibiting the development of monsoons. Locally, aerosol radiative effects alter the thermodynamic stability and convective potential of the lower atmosphere leading to reduced temperatures, increased atmospheric stability, and weakened wind and atmospheric circulations. The atmospheric thermodynamic state, which determines the formation of clouds, convection, and precipitation, may also be altered by aerosols serving as cloud condensation nuclei or ice nuclei. Absorbing aerosols such as black carbon and desert dust in Asian monsoon regions may also induce dynamical feedback processes, leading to a strengthening of the early monsoon and affecting the subsequent evolution of the monsoon. Many mechanisms have been put forth regarding how aerosols modulate the amplitude, frequency, intensity, and phase of different monsoon climate variables. A wide range of theoretical, observational, and modeling findings on the Asian monsoon, aerosols, and their interactions are synthesized. A new paradigm is proposed on investigating aerosol-monsoon interactions, in which natural aerosols such as desert dust, black carbon from

  20. Airborne observations of aerosol microphysical properties and particle ageing processes in the troposphere above Europe

    Directory of Open Access Journals (Sweden)

    T. Hamburger

    2012-12-01

    Full Text Available In-situ measurements of aerosol microphysical properties were performed in May 2008 during the EUCAARI-LONGREX campaign. Two aircraft, the FAAM BAe-146 and DLR Falcon 20, operated from Oberpfaffenhofen, Germany. A comprehensive data set was obtained comprising the wider region of Europe north of the Alps throughout the whole tropospheric column. Prevailing stable synoptic conditions enabled measurements of accumulating emissions inside the continental boundary layer reaching a maximum total number concentration of 19 000 particles cm−3 stp. Ultra-fine particles as indicators for nucleation events were observed within the boundary layer during high pressure conditions and after updraft of emissions induced by frontal passages above 8 km altitude in the upper free troposphere. Aerosol ageing processes during air mass transport are analysed using trajectory analysis. The ratio of particles containing a non-volatile core (250 °C to the total aerosol number concentration was observed to increase within the first 12 to 48 h from the particle source from 50 to 85% due to coagulation. Aged aerosol also features an increased fraction of accumulation mode particles of approximately 40% of the total number concentration. The presented analysis provides an extensive data set of tropospheric aerosol microphysical properties on a continental scale which can be used for atmospheric aerosol models and comparisons of satellite retrievals.

  1. Volcanic aerosol and ozone depletion within the Antarctic polar vortex during the austral spring of 1991

    Energy Technology Data Exchange (ETDEWEB)

    Deshler, T.; Adriani, A.; Gobbi, G.P.; Hofmann, D.J.; Donfrancesco, G. di; Johnson, B.J. (Wyoming Univ., Laramie (United States) CNR, Ist. de Fisica dell' Atmosfera, Frascati (Italy) NOAA, Climate Monitoring and Diagnostics Lab., Boulder, CO (United States) ENEA, Centro Ricerche Energia Casaccia, Rome (Italy))

    1992-09-01

    In the spring of 1991 the Antarctic lower stratosphere was characterized by a layer of volcanic aerosol from the Cerro Hudson eruption. This aerosol layer was observed from McMurdo Station, Antarctica, with both lidar and balloonborne particle counters beginning around 10 September. After 20 September the aerosol was observed daily between 9 and 13 km. In this layer homogeneous nucleation of new aerosol was observed with concentrations greater than 6000/cu cm. Comparisons of scattering ratio calculated from measured particle size distributions agree best with the lidar measurements when a real index of refraction near 1.5 is used. In the past 5 years of measurements, ozone below 13 km has been relatively unchanged during the annual Antartic ozone depletion; however, in 1991 ozone below 13 km decreased at a rate of 4 - 8 ppb/day over 30 days. This change began shortly after the appearance of the volcanic aerosol, providing direct measurements correlating volcanic aerosol and ozone depletion. 16 refs.

  2. Airborne observations of aerosol microphysical properties and particle ageing processes in the troposphere above Europe

    Science.gov (United States)

    Hamburger, T.; McMeeking, G.; Minikin, A.; Petzold, A.; Coe, H.; Krejci, R.

    2012-12-01

    In-situ measurements of aerosol microphysical properties were performed in May 2008 during the EUCAARI-LONGREX campaign. Two aircraft, the FAAM BAe-146 and DLR Falcon 20, operated from Oberpfaffenhofen, Germany. A comprehensive data set was obtained comprising the wider region of Europe north of the Alps throughout the whole tropospheric column. Prevailing stable synoptic conditions enabled measurements of accumulating emissions inside the continental boundary layer reaching a maximum total number concentration of 19 000 particles cm-3 stp. Ultra-fine particles as indicators for nucleation events were observed within the boundary layer during high pressure conditions and after updraft of emissions induced by frontal passages above 8 km altitude in the upper free troposphere. Aerosol ageing processes during air mass transport are analysed using trajectory analysis. The ratio of particles containing a non-volatile core (250 °C) to the total aerosol number concentration was observed to increase within the first 12 to 48 h from the particle source from 50 to 85% due to coagulation. Aged aerosol also features an increased fraction of accumulation mode particles of approximately 40% of the total number concentration. The presented analysis provides an extensive data set of tropospheric aerosol microphysical properties on a continental scale which can be used for atmospheric aerosol models and comparisons of satellite retrievals.

  3. Comparison between CARIBIC aerosol samples analysed by accelerator-based methods and optical particle counter measurements

    Directory of Open Access Journals (Sweden)

    B. G. Martinsson

    2014-04-01

    Full Text Available Inter-comparison of results from two kinds of aerosol systems in the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container passenger aircraft based observatory, operating during intercontinental flights at 9–12 km altitude, is presented. Aerosol from the lowermost stratosphere (LMS, the extra-tropical upper troposphere (UT and the tropical mid troposphere (MT were investigated. Aerosol particle volume concentration measured with an optical particle counter (OPC is compared with analytical results of the sum of masses of all major and several minor constituents from aerosol samples collected with an impactor. Analyses were undertaken with accelerator-based methods particle-induced X-ray emission (PIXE and particle elastic scattering analysis (PESA. Data from 48 flights during one year are used, leading to a total of 106 individual comparisons. The ratios of the particle volume from the OPC and the total mass from the analyses were in 84% within a relatively narrow interval. Data points outside this interval are connected with inlet-related effects in clouds, large variability in aerosol composition, particle size distribution effects and some cases of non-ideal sampling. Overall, the comparison of these two CARIBIC measurements based on vastly different methods show good agreement, implying that the chemical and size information can be combined in studies of the MT/UT/LMS aerosol.

  4. Airborne observations of aerosol microphysical properties and particle ageing processes in the troposphere above Europe

    Directory of Open Access Journals (Sweden)

    T. Hamburger

    2012-08-01

    Full Text Available In-situ measurements of aerosol microphysical properties were performed in May 2008 during the EUCAARI-LONGREX campaign. Two aircraft, the FAAM BAe-146 and DLR Falcon 20, operated from Oberpfaffenhofen, Germany. A comprehensive data set was obtained comprising the wider region of Europe north of the Alps throughout the whole tropospheric column. Prevailing stable synoptic conditions enabled measurements of accumulating emissions inside the continental boundary layer reaching a maximum total number concentration of 19 000 particles cm−3 stp. Nucleation events were observed within the boundary layer during high pressure conditions and after updraft of emissions induced by frontal passages above 8 km altitude in the upper free troposphere. Aerosol ageing processes during air mass transport are analysed using trajectory analysis. The ratio of particles containing a non-volatile core (250 °C to the total aerosol number concentration was observed to increase within the first 12 to 48 h from the particle source from 50 to 85% due to coagulation. Aged aerosol also features an increased fraction of accumulation mode particles of approximately 40% of the total number concentration. The presented analysis provides an extensive data set of tropospheric aerosol microphysical properties on a continental scale which can be used for atmospheric aerosol models and comparisons of satellite retrievals.

  5. Toxicity of atmospheric aerosols on marine phytoplankton

    Science.gov (United States)

    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.

  6. Marine Aerosols: Hygroscopocity and Aerosol-Cloud Relationships

    Science.gov (United States)

    2012-09-30

    large eddy simulation (LES) and field measurements, the latter including Twin Otter missions such as MASE I and MASE II and those involving other...continuous spectral aerosol-droplet microphysics model is presented and implemented into the Weather Research and Forecasting (WRF) model for large- eddy ...Dey, A. Sorooshian, F. J. Brechtel, Z. Wang, A. Metcalf , M. Coggon, J. Mulmenstadt, L. M. Russell, H. H. Jonsson, and J. H. Seinfeld, Atmos. Meas

  7. Do atmospheric aerosols form glasses?

    Science.gov (United States)

    Zobrist, B.; Marcolli, C.; Pedernera, D. A.; Koop, T.

    2008-09-01

    A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline) solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg, homogeneous ice nucleation temperatures, Thom, and ice melting temperatures, Tm, of various aqueous inorganic, organic and multi-component solutions are investigated with a differential scanning calorimeter. The investigated solutes are: various polyols, glucose, raffinose, levoglucosan, an aromatic compound, sulfuric acid, ammonium bisulfate and mixtures of dicarboxylic acids (M5), of dicarboxylic acids and ammonium sulfate (M5AS), of two polyols, of glucose and ammonium nitrate, and of raffinose and M5AS. The results indicate that aqueous solutions of the investigated inorganic solutes show Tg values that are too low to be of atmospheric importance. In contrast, aqueous organic and multi-component solutions readily form glasses at low but atmospherically relevant temperatures (≤230 K). To apply the laboratory data to the atmospheric situation, the measured phase transition temperatures were transformed from a concentration to a water activity scale by extrapolating water activities determined between 252 K and 313 K to lower temperatures. The obtained state diagrams reveal that the higher the molar mass of the aqueous organic or multi-component solutes, the higher Tg of their respective solutions at a given water activity. To a lesser extent, Tg also depends on the hydrophilicity of the organic solutes. Therefore, aerosol particles containing larger (≳150 g mol-1) and more hydrophobic organic molecules are more likely to form glasses at intermediate to high relative humidities in the upper troposphere

  8. Do atmospheric aerosols form glasses?

    Directory of Open Access Journals (Sweden)

    D. A. Pedernera

    2008-09-01

    Full Text Available A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg, homogeneous ice nucleation temperatures, Thom, and ice melting temperatures, Tm, of various aqueous inorganic, organic and multi-component solutions are investigated with a differential scanning calorimeter. The investigated solutes are: various polyols, glucose, raffinose, levoglucosan, an aromatic compound, sulfuric acid, ammonium bisulfate and mixtures of dicarboxylic acids (M5, of dicarboxylic acids and ammonium sulfate (M5AS, of two polyols, of glucose and ammonium nitrate, and of raffinose and M5AS. The results indicate that aqueous solutions of the investigated inorganic solutes show Tg values that are too low to be of atmospheric importance. In contrast, aqueous organic and multi-component solutions readily form glasses at low but atmospherically relevant temperatures (≤230 K. To apply the laboratory data to the atmospheric situation, the measured phase transition temperatures were transformed from a concentration to a water activity scale by extrapolating water activities determined between 252 K and 313 K to lower temperatures. The obtained state diagrams reveal that the higher the molar mass of the aqueous organic or multi-component solutes, the higher Tg of their respective solutions at a given water activity. To a lesser extent, Tg also depends on the hydrophilicity of the organic solutes. Therefore, aerosol particles containing larger (≳150 g mol−1 and

  9. Do atmospheric aerosols form glasses?

    Directory of Open Access Journals (Sweden)

    B. Zobrist

    2008-05-01

    Full Text Available A new process is presented by which water-soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg, homogeneous ice nucleation temperatures, Thom, and ice melting temperatures, Tm, of various aqueous inorganic, organic and multi-component solutions are investigated with a differential scanning calorimeter. The investigated solutes are: various polyols, glucose, raffinose, levoglucosan, an aromatic compound, sulfuric acid, ammonium bisulphate and mixtures of dicarboxylic acids (M5, of dicarboxylic acids and ammonium sulphate (M5AS, of two polyols, of glucose and ammonium nitrate, and of raffinose and M5AS. The results indicate that aqueous solutions of the investigated inorganic solutes show Tg-values that are too low to be of atmospheric importance. In contrast, aqueous organic and multi-component solutions readily form glasses at low but atmospherically relevant temperatures (≤230 K. To apply the laboratory data to the atmospheric situation, the measured phase transition temperatures were transformed from a concentration to a water activity scale by extrapolating water activities determined between 252 K and 313 K to lower temperatures. The obtained state diagrams reveal that the higher the molar mass of the aqueous organic or multi-component solutes, the higher Tg of their respective solutions at a given water activity. To a lesser extent, Tg also depends on the hydrophilicity of the organic solutes. Therefore, aerosol particles containing larger and more hydrophobic organic

  10. Size-resolved and bulk activation properties of aerosols in the North China plain: the importance of aerosol size distribution in the prediction of CCN number concentration

    Directory of Open Access Journals (Sweden)

    Z. Z. Deng

    2011-01-01

    Full Text Available Size-resolved and bulk activation properties of aerosols were measured at a regional/suburban site in the North China Plain (NCP, which is occasionally heavily polluted by anthropogenic aerosol particles and gases. A CCN (Cloud Condensation Nuclei closure study is conducted with bulk CCN number concentration (NCCN and calculated NCCN based on the aerosol number size distribution and size-resolved activation properties.

    The observed NCCN are higher than those observed in other locations than China, with average NCCN of roughly 2000, 3000, 6000, 10 000 and 13 000 cm−3 at supersaturations of 0.056, 0.083, 0.17, 0.35 and 0.70%, respectively. An inferred critical dry diameter (Dm is calculated based on the measured NCCN and aerosol number size distribution assuming homogeneous chemical composition. This inferred cut off diameter varies in a wide range, indicating that it is impossible to predict NCCN with a fixed critical diameter.

    Size-resolved activation measurements show that most of the 300 nm particles are activated at the investigated supersaturations, while almost no particles of 30 nm are activated even at the highest supersaturation of 0.72%. The activation ratio increases with increasing supersaturation and particle size. The slopes of the activation curves for ambient aerosols are not as steep as those observed in calibrations with ammonium sulfate suggesting that the observed aerosols is an external mixture of more hygroscopic and hydrophobic particles. This conclusion is confirmed by hygroscopicity measurements performed during two intensive field studies in 2009.

    The calculated NCCN based on the size-resolved activation ratio and aerosol number size distribution correlate well with the measured NCCN, and show an average overestimation

  11. Characterization of biogenic secondary organic aerosols using statistical methods; Charakterisierung Biogener Sekundaerer Organischer Aerosole mit Statistischen Methoden

    Energy Technology Data Exchange (ETDEWEB)

    Spindler, Christian

    2010-07-01

    spectral characteristics of aerosol from different precursor mixtures or of different age, statistical methods comprise a major part of the analysis performed in this work. First, hierarchical cluster analysis is used to classify similar mass spectra. This method is based on the distances between pairs of mass spectra and is helpful to distinguish between groups of very similar data sets. Cluster analysis operates on static mass spectra and does not incorporate time-dependent processes. As a result it is found that the chemical composition of BSOA is almost independent from the detailed composition of the terpene precursor mixture. Second, elemental analysis of the mass spectra is performed using the high resolving power of the time-of-flight AMS. For each mass spectrum, the ratio of oxygen to carbon atoms, O/C, can be calculated by knowing the chemical composition of the individual fragments and counting the respective elements. This analysis helps interpreting the results from the statistical methods. The temporal evolution of O/C can be directly interpreted as an aging process. The evolution is further compared to the oxidation conditions of the respective experiments. It is found that the temporal O/C evolution in SAPHIR experiments is strongly dependent on the abundance of OH. Finally, a matrix factorization method constraining the entries in the solution matrices to positive values (PMF) is applied to determine factors in aging experiments. The results are linked to fragment distributions in high-resolved mass spectra and to external measurements of terpene oxidation products. A main result from PMF is that the chemical composition of BSOA particles is a combination of many parallel processes with different time constants. Additional measurements were performed on heated aerosol to infer the volatility and changes in the chemical composition with evaporation of the most volatile compounds. The discussion of the results from these measurements forms the final chapter

  12. Ground-based aerosol characterization during the South American Biomass Burning Analysis (SAMBBA) field experiment

    Science.gov (United States)

    Brito, J.; Rizzo, L. V.; Morgan, W. T.; Coe, H.; Johnson, B.; Haywood, J.; Longo, K.; Freitas, S.; Andreae, M. O.; Artaxo, P.

    2014-11-01

    This paper investigates the physical and chemical characteristics of aerosols at ground level at a site heavily impacted by biomass burning. The site is located near Porto Velho, Rondônia, in the southwestern part of the Brazilian Amazon rainforest, and was selected for the deployment of a large suite of instruments, among them an Aerosol Chemical Speciation Monitor. Our measurements were made during the South American Biomass Burning Analysis (SAMBBA) field experiment, which consisted of a combination of aircraft and ground-based measurements over Brazil, aimed to investigate the impacts of biomass burning emissions on climate, air quality, and numerical weather prediction over South America. The campaign took place during the dry season and the transition to the wet season in September/October 2012. During most of the campaign, the site was impacted by regional biomass burning pollution (average CO mixing ratio of 0.6 ppm), occasionally superimposed by intense (up to 2 ppm of CO), freshly emitted biomass burning plumes. Aerosol number concentrations ranged from ~1000 cm-3 to peaks of up to 35 000 cm-3 (during biomass burning (BB) events, corresponding to an average submicron mass mean concentrations of 13.7 μg m-3 and peak concentrations close to 100 μg m-3. Organic aerosol strongly dominated the submicron non-refractory composition, with an average concentration of 11.4 μg m-3. The inorganic species, NH4, SO4, NO3, and Cl, were observed, on average, at concentrations of 0.44, 0.34, 0.19, and 0.01 μg m-3, respectively. Equivalent black carbon (BCe) ranged from 0.2 to 5.5 μg m-3, with an average concentration of 1.3 μg m-3. During BB peaks, organics accounted for over 90% of total mass (submicron non-refractory plus BCe), among the highest values described in the literature. We examined the ageing of biomass burning organic aerosol (BBOA) using the changes in the H : C and O : C ratios, and found that throughout most of the aerosol processing (O : C ≅ 0

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

    Science.gov (United States)

    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. The formation of secondary organic aerosol from the isoprene + OH reaction in the absence of NOx

    Directory of Open Access Journals (Sweden)

    M. Jaoui

    2009-04-01

    Full Text Available The reaction of isoprene (C5H8 with hydroxyl radicals has been studied in the absence of nitrogen oxides (NOx to determine physical and chemical characteristics of the secondary organic aerosol formed. Experiments were conducted using a smog chamber operated in a steady-state mode permitting measurements of moderately low aerosol levels. GC-MS analysis was conducted to measure methyl butenediols in the gas phase and polyols in the aerosol phase. Analyses were made to obtain several bulk aerosol parameters from the reaction including values for the organic mass to organic carbon ratio, the effective enthalpy of vaporization (ΔHvapeff, the organic peroxide fraction, and the aerosol yield. The gas phase analysis showed the presence of methacrolein, methyl vinyl ketone, and four isomers of the methyl butenediols. These gas-phase compounds may serve as precursors for one or more of several compounds detected in the aerosol phase including 2-methylglyceric acid, three 2-methyl alkenetriols, and two 2-methyl tetrols. In contrast to most previous studies, the 2-methyl tetrols (and the 2-methyl alkenetriols were found to form in the absence of acidic sulfate aerosol. A re-evaluation of field samples in Research Triangle Park, North Carolina, during the summers of 2000 and 2001 indicated in the presence of the methyl butenediols from gas-phase denuder samples taken at the time. SOA/SOC (i.e., OM/OC was found to average 1.9 in the absence of NOx. The effective enthalpy of vaporization was measured as 38.6 kJ mol−1, consistent with values that have previously been used in modeling studies. The yields in this work (using an independent technique than that previous are lower than those of Kroll et al. (2006 for similar aerosol masses. SOC yields reported in this work range from 0.5–1.4% for carbon masses between 17 and 49 μgC m−3.

  15. Preliminary characterization of submicron secondary aerosol in the amazon forest - ATTO station

    Science.gov (United States)

    Carbone, S.; Ferreira De Brito, J.; Andreae, M. O.; Pöhlker, C.; Chi, X.; Saturno, J.; Barbosa, H. M.; Artaxo, P.

    2014-12-01

    Biogenic secondary organic aerosol particles are investigated in the Amazon in the context of the GoAmazon Project. The forest naturally emits a large number of gaseous compounds; they are called the volatile organic compounds (VOCs). They are emitted through processes that are not totally understood. Part of those gaseous compounds are converted into aerosol particles, which affect the biogeochemical cycles, the radiation balance, the mechanisms involving cloud formation and evolution, among few other important effects. In this study the aerosol life-cycle is investigated at the ATTO station, which is located about 150 km northeast of Manaus, with emphasis on the natural organic component and its impacts in the ecosystem. To achieve these objectives physical and chemical aerosol properties have been investigated, such as the chemical composition with aerosol chemical speciation monitor (ACSM), nanoparticle size distribution (using the SMPS - Scanning Mobility Particle Sizer), optical properties with measurements of scattering and absorption (using nephelometers and aethalometers). Those instruments have been operating continuously since February 2014 together with trace gases (O3, CO2, CO, SO2 and NOx) analyzers and additional meteorological instruments. On average PM1 (the sum of black carbon, organic and inorganic ions) totalized 1.0±0.3 μg m-3, where the organic fraction was dominant (75%). During the beginning of the dry season (July/August) the organic aerosol presented a moderate oxygenated character with the oxygen to carbon ratio (O:C) of 0.7. In the wet season some episodes containing significant amount of chloride and backward wind trajectories suggest aerosol contribution from the Atlantic Ocean. A more comprehensive analysis will include an investigation of the different oxidized fractions of the organic aerosol and optical properties.

  16. Investigating the use of secondary organic aerosol as seed particles in simulation chamber experiments

    Directory of Open Access Journals (Sweden)

    J. F. Hamilton

    2011-06-01

    Full Text Available The use of β-caryophyllene secondary organic aerosol particles as seeds for smog chamber simulations has been investigated. A series of experiments were carried out in the Manchester photochemical chamber as part of the Aerosol Coupling in the Earth System (ACES project to study the effect of seed particles on the formation of secondary organic aerosol (SOA from limonene photo-oxidation. Rather than use a conventional seed aerosol containing ammonium sulfate or diesel particles, a method was developed to use in-situ chamber generated seed particles from β-caryophyllene photo-oxidation, which were then diluted to a desired mass loading (in this case 4–13 μg m−3. Limonene was then introduced into the chamber and oxidised, with the formation of SOA seen as a growth in the size of oxidised organic seed particles from 150 to 325 nm mean diameter. The effect of the partitioning of limonene oxidation products onto the seed aerosol was assessed using aerosol mass spectrometry during the experiment and the percentage of m/z 44, an indicator of degree of oxidation, increased from around 5 to 8 %. The hygroscopicity of the aerosol also changed, with the growth factor for 200 nm particles increasing from less than 1.05 to 1.25 at 90 % RH. The detailed chemical composition of the limonene SOA could be extracted from the complex β-caryophyllene matrix using two-dimensional gas chromatography (GC × GC and liquid chromatography coupled to mass spectrometry. High resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS was used to determine exact molecular formulae of the seed and the limonene modified aerosol. The average O:C ratio was seen to increase from 0.32 to 0.37 after limonene oxidation products had condensed onto the organic seed.

  17. Investigating the use of secondary organic aerosol as seed particles in simulation chamber experiments

    Directory of Open Access Journals (Sweden)

    J. F. Hamilton

    2010-10-01

    Full Text Available The use of β-caryophyllene secondary organic aerosol particles as seeds for smog chamber simulations has been investigated. A series of experiments were carried out in the Manchester photochemical chamber as part of the Aerosol Coupling in the Earth System (ACES project to study the effect of seed particles on the formation of secondary organic aerosol (SOA from limonene photo-oxidation. Rather than use a conventional seed aerosol containing ammonium sulphate or diesel particles, a method was developed to use in situ chamber generated seed particles from β-caryophyllene photo-oxidation, which were then diluted to a desired mass loading (in this case 4–13 μg m-3. Limonene was then introduced into the chamber and oxidised, with the formation of SOA seen as a growth in the size of oxidised organic seed particles from 150 to 325 nm mean diameter. The effect of the partitioning of limonene oxidation products onto the seed aerosol was assessed using aerosol mass spectrometry during the experiment and the percentage of m/z 44, an indicator of degree of oxidation, increased from around 5 to 8%. The hygroscopicity of the aerosol also changed, with the growth factor for 200 nm particles increasing from less than 1.05 to 1.25 at 90% RH. The detailed chemical composition of the limonene SOA could be extracted from the complex β-caryophyllene matrix using two-dimensional gas chromatography (GC×GC and liquid chromatography coupled to mass spectrometry. High resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS was used to determine exact molecular formulae of the seed and the limonene modified aerosol. The average O:C ratio was seen to increase from 0.32 to 0.37 after limonene oxidation products had condensed onto the organic seed.

  18. [Aerosol optical properties during different air-pollution episodes over Beijing].

    Science.gov (United States)

    Shi, Chan-Zhen; Yu, Xing-Na; Zhou, Bin; Xiang, Lei; Nie, Hao-Hao

    2013-11-01

    Based on the 2005-2011 data from Aerosol Robotic Network (AERONET), this study conducted analysis on aerosol optical properties over Beijing during different air-pollution episodes (biomass burning, CNY firework, dust storm). The aerosol optical depth (AOD) showed notable increases in the air-pollution episodes while the AOD (at 440 nm) during dust storm was 4. 91, 4. 07 and 2.65 times higher as background, biomass burning and firework aerosols. AOD along with Angstrom exponent (alpha) can be used to determine the aerosol types. The dust aerosol had the highest AOD and the lowest alpha. The alpha value of firework (1.09) was smaller than biomass burning (1.21) and background (1.27), indicating that coarse particles were dominant in the former type. Higher AOD of burnings (than background) can be attributed to the optical extinction capability of black carbon aerosol. The single scattering albedo (SSA) was insensitive to wavelength. The SSA value of dust (0.934) was higher than background (0.878), biomass burning (0.921) and firework (0.905). Additionally, the extremely large SSA of burnings here maybe was caused by the aging smoke, hygroscopic growth and so on. The peak radius of aerosol volume size distributions were 0.1-0.2 microm and 2.24 -3.85 microm in clear and polluted conditions. The value of volume concentration ratio between coarse and fine particles was in the order of clear background (1.04), biomass burning (1.10), CNY firework (1.91) and dust storm (4.96) episode.

  19. Quantifying organic aerosol single scattering albedo over the tropical biomass burning regions

    Science.gov (United States)

    Chu, Jung-Eun; Ha, Kyung-Ja

    2016-12-01

    Despite growing evidence of light-absorbing organic aerosols (OAs), their contribution to the Earth's radiative budget is still poorly understood. In this study we derived a new empirical relationship that binds OA single scattering albedo (SSA), which is the ratio of light scattering to extinction, with sulfate + nitrate aerosol optical depth (AOD) and applied this method to estimate OA SSA over the tropical biomass burning regions. This method includes division of the attribution of black carbon (BC) and OA absorption aerosol optical depths from the Aerosol Robotic Network (AERONET) observation and determination of the fine-mode ratio of sea-salt and dust AODs from several atmospheric chemistry models. Our best estimate of OA SSA over the tropical biomass burning regions is 0.91 at 550 nm. Uncertainties associated with observations and models permit a value range of 0.82-0.93. Furthermore, by using the estimated OA SSA and comprehensive observations including AERONET, Moderate Resolution Imaging Spectroradiometer (MODIS) and Multi-angle Imaging Spectroradiometer (MISR), we examined the first global estimate of sulfate + nitrate AOD through a semi-observational approach. The global mean sulfate + nitrate AOD of 0.017 is in the lower range of the values obtained from 21 models participated in AeroCom phase II. The results imply that most aerosol models as well as climate models, which commonly use OA SSA of 0.96-1.0, have so far ignored light absorption by OAs and have overestimated light scattering by sulfate + nitrate aerosols. This indicates that the actual aerosol direct radiative forcing should be less negative than currently believed.

  20. Insights into Submicron Aerosol Composition and Sources from the WINTER Aircraft Campaign Over the Eastern US.

    Science.gov (United States)

    Schroder, J. C.; Campuzano Jost, P.; Day, D. A.; Fibiger, D. L.; McDuffie, E. E.; Blake, N. J.; Hills, A. J.; Hornbrook, R. S.; Apel, E. C.; Weinheimer, A. J.; Campos, T. L.; Brown, S. S.; Jimenez, J. L.

    2015-12-01

    The WINTER aircraft campaign was a recent field experiment to probe the sources and evolution of gas pollutants and aerosols in Northeast US urban and industrial plumes during the winter. A highly customized Aerodyne aerosol mass spectrometer (AMS) was flown on the NCAR C-130 to characterize submicron aerosol composition and evolution. Thirteen research flights were conducted covering a wide range of conditions, including rural, urban, and marine environments during day and night. Organic aerosol (OA) was a large component of the submicron aerosol in the boundary layer. The fraction of OA (fOA) was smaller (35-40%) than in recent US summer campaigns (~60-70%). Biomass burning was observed to be an important source of OA in the boundary layer, which is consistent with recent wintertime studies that show a substantial contribution of residential wood burning to the OA loadings. OA oxygenation (O/C ratio) shows a broad distribution with a substantial fraction of smaller O/C ratios when compared to previous summertime campaigns. Since measurements were rarely made very close to primary sources (i.e. directly above urban areas), this is consistent with oxidative chemistry being slower during winter. SOA formation and aging in the NYC plume was observed during several flights and compared with summertime results from LA (CalNex) and Mexico City (MILAGRO). Additionally, an oxidation flow reactor (OFR) capable of oxidizing ambient air up to several equivalent days of oxidation was deployed for the first time in an aircraft platform. The aerosol outflow of the OFR was sampled with the AMS to provide real-time snapshots of the potential for aerosol formation and aging. For example, a case study of a flight through the Ohio River valley showed evidence of oxidation of SO2 to sulfate. The measured sulfate enhancements were in good agreement with our OFR chemical model. OFR results for SOA will be discussed.

  1. Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    J. Dron

    2010-04-01

    Full Text Available The functional group composition of various organic aerosols (OA is being investigated using a recently developed analytical approach based on atmospheric pressure chemical ionisation-tandem mass spectrometry (APCI-MS/MS. The determinations of the three functional groups' contents are performed quantitatively by neutral loss (carboxylic and carbonyl groups and precursor ion (nitro groups scanning modes of a tandem mass spectrometer. Major organic aerosol sources are studied: vehicular emission and wood combustion for primary aerosol sources; and a secondary organic aerosol (SOA produced through photo-oxidation of o-xylene. The results reveal significant differences in the functional group contents of these source aerosols. The laboratory generated SOA is dominated by carbonyls while carboxylics are preponderate in the wood combustion particles. On the other hand, vehicular emissions are characterised by a strong nitro content. The total amount of the three functional groups accounted for 1.7% (vehicular to 13.5% (o-xylene photo-oxidation of the organic carbon. The diagnostic functional group ratios are then used to tentatively differentiate sources of particles collected in an urban background environment located in an Alpine valley (Chamonix, France during a strong winter pollution event. The three functional groups under study account for a total functionalisation rate of 2.2 to 3.8% of the organic carbon in this ambient aerosol, which is also dominated by carboxylic moieties. In this particular case study of a deep alpine valley during winter, we show that the nitro- and carbonyl-to-carboxylic diagnostic ratios can be a useful tool to distinguish the sources. In these conditions, the total OA concentrations are highly dominated by wood combustion OA. This result is confirmed by an organic markers source apportionment approach which assesses a wood burning organic carbon contribution of about 60%. Finally, examples of functional group mass

  2. Scattering Properties of Atmospheric Aerosols over Lanzhou City and Applications Using an Integrating Nephelometer

    Institute of Scientific and Technical Information of China (English)

    张武; 胡波; 陈长和; 杜萍; 张镭; 冯广泓

    2004-01-01

    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.

  3. Some results of water vapor, ozone and aerosol balloon borne measurements during EASOE

    Science.gov (United States)

    Khattatov, V.; Yushkov, V.; Khaplanov, M.; Zaitzev, I.; Rosen, J.; Kjome, N.

    As part of the European Arctic Stratospheric Ozone Experiment (EASOE) in the northern winter of 1991/92, regular measurements of the vertical distribution of ozone and aerosols were carried out from two Russian polar stations, Heiss Island (81N, 58E) and Dikson Island (73N, 81E). In addition measurements of the vertical distribution of water vapor and aerosols were made from Esrange (68N, 21E), near Kiruna in Sweden. The instruments used were electrochemical ozone sondes (ECC-4A), a fluorescence hygrometer, and the University of Wyoming backscattersonde. Following the eruption of Mt.Pinatubo, in the Philippines, in June 1991, volcanic aerosol had reached Arctic latitudes at altitudes below 19 km by September. At all three sites it was observed on every flight. Polar stratospheric clouds were encountered above the volcanic aerosol on two flights from Esrange. There were no indications of dehydration in the Arctic stratosphere. On all flights the minimum mixing ratio of water vapor was observed 2 to 3 km above the tropopause. Total ozone was much lower than the climatological mean, over Dikson Island from the January 27, and over Heiss Island from mid-February, until the end of EASOE. Ozone profiles over these stations showed rapid increases in partial pressure immediately above the peak values of backscatter ratio when the volcanic aerosol was especially dense.

  4. CCN activity of aliphatic amine secondary aerosol

    Directory of Open Access Journals (Sweden)

    X. Tang

    2014-01-01

    Full Text Available Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical. The particle composition can contain both secondary organic aerosol (SOA and inorganic salts. The fraction of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN activity. SOA formed from trimethylamine (TMA and butylamine (BA reactions with hydroxyl radical (OH is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ ≤ 0.25. Secondary aerosol formed from the tertiary aliphatic amine (TMA with N2O5 (source of nitrate radical, NO3, contains less volatile compounds than the primary aliphatic amine (BA aerosol. TMA + N2O5 form semi-volatile organics in low RH conditions that have κ ~ 0.20, indicative of slightly soluble organic material. As RH increases, several inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR ideal mixing rules. Higher CCN activity (κ > 0.3 was also observed for humid BA+N2O5 aerosols compared with dry aerosol (κ ~ 0.2, as a result of the formation of inorganic salts such as NH4NO3 and butylamine nitrate (C4H11N · HNO3. Compared with TMA, BA+N2O5 reactions produce more volatile aerosols. The BA+N2O5 aerosol products under humid experiments were found to be very sensitive to the temperature within the stream-wise continuous flow thermal gradient CCN counter. The CCN counter, when set above a 21 °C temperature difference, evaporates BA+N2O5 aerosol formed at RH ≥ 30%; κ ranges from 0.4 to 0.7 and is dependent on the instrument supersaturation (ss settings. The aerosol behaves non-ideally, hence simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems κ ranges from 0.2 < κ < 0.7. This work indicates that

  5. Comparison of Aerosol Optical Depth from GOES Aerosol and Smoke Product (GASP) and MODIS to AERONET AOD and IMPROVE PM2.5 Mass at Bondville, Illinois Stratified by Chemical Composition, RH, Particle Size, and Season

    Science.gov (United States)

    Green, M. C.; Kondragunta, S.; Ciren, P.

    2008-05-01

    The USEPA is interested in using satellite remote sensing data to estimate levels of PM2.5. Here we report on comparisons of aerosol optical depth (AOD) from GOES Aerosol and Smoke Product (GASP) and the Moderate Resolution Imaging Spectroradiometer (MODIS) to IMPROVE network PM2.5 mass and AErosol RObotic NETwork (AERONET) ground-based AOD. Before we compare GASP and MODIS AOD to PM2.5, we first evaluate satellite AOD using the ground-based AERONET measurements and how it varies by aerosol chemical composition and size distribution. We focus attention on the Bondville, Illinois site because there is collocated IMPROVE sampling and an AERONET site. GASP provides aerosol optical depth at 0.55 um using top of atmosphere visible channel radiance measured from GOES east and GOES west. Time resolution is typically every 30 minutes during daylight hours. MODIS provides typically once per day AOD for any given location. The IMPROVE sampler provides a 24-hour integrated sample of PM10 mass, and PM2.5 mass and elemental composition on a one day in three schedule. AERONET provides aerosol optical depth at multiple wavelengths and aerosol size distribution as well as other derived parameters such as Angstrom exponent from ground based daytime measurements. We stratified cases by RH group, major chemical component, size distribution, and season. GOES AOD correlated best with PM2.5 mass during periods with mainly small particles, moderate RH, and sulfate dominated aerosol. It correlated poorly when RH is very high or low, aerosol is primarily organic, and when coarse to fine mass ratio is high. GASP AOD also correlated best with AERONET AOD when particles are mainly fine, suggesting the aerosol model assumptions (e.g. size distribution) may need to be varied geographically for GASP to achieve better AOD results.

  6. Aerosol Properties over Southeastern China from Multi-Wavelength Raman and Depolarization Lidar Measurements

    Science.gov (United States)

    Heese, Birgit; Althausen, Dietrich; Baars, Holger; Bohlmann, Stephanie; Deng, Ruru

    2016-06-01

    A dataset of particle optical properties of highly polluted urban aerosol over the Pearl River Delta, Guangzhou, China is presented. The data were derived from multi-wavelengths Raman and depolarization lidar PollyXT and AERONET sun photometer measurements. The measurement campaign was conducted from Nov 2011 to June 2012. High aerosol optical depth was observed in the polluted atmosphere over this megacity, with a mean value of 0.54 ± 0.33 and a peak value of even 1.9. For the particle characterization the lidar ratio and the linear particle depolarization ratio, both at 532 nm, were used. The mean values of these properties are 48.0 sr ± 10.7 sr for the lidar ratio and 4%+-4% for the particle depolarization ratio, which means most depolarization measurements stayed below 10%. So far, most of these results indicate urban pollution particles mixed with particles arisen from biomass and industrial burning.

  7. Intake to Production Ratio

    DEFF Research Database (Denmark)

    Nazaroff, William; Weschler, Charles J.; Little, John C.

    2012-01-01

    population (inferred from urinary excretion data) divided by the rate that chemical is produced in or imported into that population's economy. We used biomonitoring data from the U.S. Centers for Disease Control and Prevention along with chemical manufacturing data reported by the U.S. Environmental...... to protect public health.OBJECTIVES: We introduce the intake-to-production ratio (IPR) as an economy-wide quantitative indicator of the extent to which chemical production results in human exposure.METHODS: The IPR was evaluated as the ratio of two terms: aggregate rate of chemical uptake in a human...... Protection Agency, as well as other published data, to estimate the IPR for nine chemicals in the United States. Results are reported in units of parts per million, where 1 ppm indicates 1 g of chemical uptake for every million grams of economy-wide use.RESULTS: Estimated IPR values for the studied compounds...

  8. MATRIX-VBS: implementing an evolving organic aerosol volatility in an aerosol microphysics model

    OpenAIRE

    Gao, Chloe Y.; Tsigaridis, Kostas; Bauer, Susanne E.

    2016-01-01

    We have implemented an existing aerosol microphysics scheme into a box model framework and extended it to represent gas-particle partitioning and chemical ageing of semi-volatile organic aerosols. We then applied this new research tool to investigate the effects of semi-volatile organic species on the growth, composition and mixing state of aerosol partic