Science.gov

Sample records for aerosol experiments nspp

  1. Ganges valley aerosol experiment.

    SciTech Connect

    Kotamarthi, V.R.; Satheesh, S.K.

    2011-08-01

    In June 2011, the Ganges Valley Aerosol Experiment (GVAX) began in the Ganges Valley region of India. The objective of this field campaign is to obtain measurements of clouds, precipitation, and complex aerosols to study their impact on cloud formation and monsoon activity in the region.

  2. The influence of fog parameters on aerosol depletion measured in the KAEVER experiments

    SciTech Connect

    Poss, G.; Weber, D.; Fritsche, B.

    1995-12-31

    The release of radioactive aerosols in the environment is one of the most serious hazards in case of an accident in nuclear power plant. Many efforts have been made in the past in numerous experimental programs like NSPP, DEMONA, VANAM, LACE, MARVIKEN, others are still underway to improve the knowledge of the aerosol behavior and depletion in a reactor containment in order to estimate the possible source term and to validate computer codes. In the German single compartment KAEVER facility the influence of size distribution, morphology, composition and solubility on the aerosol behavior is investigated. One of the more specific items is to learn about {open_quotes}wet depletion{close_quotes} means, the aerosol depletion behavior in condensing atmospheres. There are no experiments known where the fog parameters like droplet size distribution, volume concentration, respectively airborne liquid water content have been measured in- and on-line explicitly. To the authors knowledge the use of the Battelle FASP photometer, which was developed especially for this reason, for the first time gives insight in condensation behavior under accident typical thermal hydraulic conditions. It delivers a basis for code validation in terms of a real comparison of measurements and calculations. The paper presents results from {open_quotes}wet depletion{close_quotes} aerosol experiments demonstrating how depletion velocity depends on the fog parameters and where obviously critical fog parameter seem to change the regime from a {open_quotes}pseudo dry depletion{close_quotes} at a relative humidity of 100% but quasi no or very low airborne liquid water content to a real {open_quotes}wet depletion{close_quotes} under the presence of fogs with varying densities. Characteristics are outlined how soluble and insoluble particles as well as aerosol mixtures behave under condensing conditions.

  3. Aerosol retrieval experiments in the ESA Aerosol_cci project

    NASA Astrophysics Data System (ADS)

    Holzer-Popp, T.; de Leeuw, G.; 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.

    2013-03-01

    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 and their mixing ratios. 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 visible analysis of monthly mean AOD maps and quantitatively by comparing global daily gridded satellite data against daily

  4. Aerosol retrieval experiments in the ESA Aerosol_cci project

    NASA Astrophysics Data System (ADS)

    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

  5. Aerosol release and transport program. Semiannual progress report, October 1985-March 1986. Volume 3, No. 1

    SciTech Connect

    Adams, R.E.; Tobias, M.L.

    1986-06-01

    This report summarizes progress for the Aerosol Release and Transport Program sponsored by the Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, Division of Accident Evaluation, for the period October 1985-March 1986. Topics discussed include (1) Aerosol-Moisture Interaction Test (AMIT) experiments 5002 through 5006; (2) efforts to measure the aerodynamic shape factor chi during these experiments; (3) a development test for determining parameters for generating concrete aerosols; (4) data concerning water-vapor generation during plasma torch operation; (5) the use of the ideal gas law in calculating relative humidity; (6) initial comparisons of CONTAIN code results with experimental data for an iron oxide aerosol-steam experiment in the NSPP Facility; (7) pretest predictions using the CONTAIN code for LACE experiment LA-2.

  6. SAGE II inversion algorithm. [Stratospheric Aerosol and Gas Experiment

    NASA Technical Reports Server (NTRS)

    Chu, W. P.; Mccormick, M. P.; Lenoble, J.; Brogniez, C.; Pruvost, P.

    1989-01-01

    The operational Stratospheric Aerosol and Gas Experiment II multichannel data inversion algorithm is described. Aerosol and ozone retrievals obtained with the algorithm are discussed. The algorithm is compared to an independently developed algorithm (Lenoble, 1989), showing that the inverted aerosol and ozone profiles from the two algorithms are similar within their respective uncertainties.

  7. Aerosol effects and corrections in the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Hervig, Mark E.; Russell, James M., III; Gordley, Larry L.; Daniels, John; Drayson, S. Roland; Park, Jae H.

    1995-01-01

    The eruptions of Mt. Pinatubo in June 1991 increased stratospheric aerosol loading by a factor of 30, affecting chemistry, radiative transfer, and remote measurements of the stratosphere. The Halogen Occultation Experiment (HALOE) instrument on board Upper Atmosphere Research Satellite (UARS) makes measurements globally for inferring profiles of NO2, H2O, O3, HF, HCl, CH4, NO, and temperature in addition to aerosol extinction at five wavelengths. Understanding and removing the aerosol extinction is essential for obtaining accurate retrievals from the radiometer channels of NO2, H2O and O3 in the lower stratosphere since these measurements are severely affected by contaminant aerosol absorption. If ignored, aerosol absorption in the radiometer measurements is interpreted as additional absorption by the target gas, resulting in anomalously large mixing ratios. To correct the radiometer measurements for aerosol effects, a retrieved aerosol extinction profile is extrapolated to the radiometer wavelengths and then included as continuum attenuation. The sensitivity of the extrapolation to size distribution and composition is small for certain wavelength combinations, reducing the correction uncertainty. The aerosol corrections extend the usable range of profiles retrieved from the radiometer channels to the tropopause with results that agree well with correlative measurements. In situations of heavy aerosol loading, errors due to aerosol in the retrieved mixing ratios are reduced to values of about 15, 25, and 60% in H2O, O3, and NO2, respectively, levels that are much less than the correction magnitude.

  8. Comparison of aerosol code predictions with experimental observations on the behavior of aerosols in steam

    SciTech Connect

    Tobias, M.L.

    1983-01-01

    Several computer codes have been developed to predict the behavior of aerosols in steam, a situation which is expected to occur in a light-water reactor accident. Among the codes with capabilities in this respect are MAEROS (Sandia) AEROMECH (University of Missouri) and NAUA-Mod4 (Karlsruhe). NAUA was specifically developed to model steam-aerosol behavior in hypothetical accidents in pressurized water reactors. It is based upon a series of experiments, in which aerosols of uranium oxide, platinum oxide, and sodium nitrate were generated in a steam atmosphere. Several series of experiments have been conducted in the NSPP vessel using aerosols generated by plasma torch in a steam-air atmosphere. From these experiments we have selected those performed with iron oxide or uranium oxide for comparison with various computer codes, principally NAUA-Mod4. Comparisons of particle size are displayed also. Results of parameter studies to determine the sensitivity of the calculated results to the steam input level, initial particle size, deposition parameters, and assumed particle density are presented.

  9. Discrimination of cloud and aerosol in the Stratospheric Aerosol and Gas Experiment III occultation data.

    PubMed

    Kent, G S; Wang, P H; Skeens, K M

    1997-11-20

    The Stratospheric Aerosol and Gas Experiment (SAGE) III, scheduled for a first launch in mid-1998, will be making measurements of the extinction that is due to aerosols and gases at many wavelengths between 385 and 1550 nm. In the troposphere and wintertime polar stratosphere, extinction will also occur because of the presence of cloud along the optical path from the Sun to the satellite instrument. We describe a method for separating the effects of aerosol and cloud using the extinction at 525, 1020, and 1550 nm and present the results of simulation studies. These studies show that the new method will work well under background nonvolcanic aerosol conditions in the upper troposphere and lower stratosphere. Under conditions of severe volcanic contamination, the error rate for the separation of aerosol and cloud may rise as high as 30%.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

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

    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.

  12. Aged organic aerosol in the Eastern Mediterranean: the Finokalia aerosol measurement experiment-2008

    NASA Astrophysics Data System (ADS)

    Hildebrandt, L.; Engelhart, G. J.; Mohr, C.; Kostenidou, E.; Lanz, V. A.; Bougiatioti, A.; Decarlo, P. F.; Prévôt, A. S. H.; Baltensperger, U.; Mihalopoulos, N.; Donahue, N. M.; Pandis, S. N.

    2010-01-01

    Aged organic aerosol (OA) was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2008 (FAME-2008), which was part of the EUCAARI intensive campaign of May 2008. The site at Finokalia is influenced by air masses from different source regions, including long-range transport of pollution from continental Europe. A quadrupole aerosol mass spectrometer (Q-AMS) was employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1), and to estimate the extent of oxidation of the organic aerosol. Factor analysis was used to gain insights into the processes and sources affecting the OA composition. The particles were internally mixed and liquid. The largest fraction of the dry NR-PM1 sampled was ammonium sulfate and ammonium bisulfate, followed by organics and a small amount of nitrate. The variability in OA composition could be explained with two factors of oxygenated organic aerosol (OOA) with differing extents of oxidation but similar volatility. Hydrocarbon-like organic aerosol (HOA) was not detected. There was no statistically significant diurnal variation in the bulk composition of NR-PM1 such as total sulfate or total organic aerosol concentrations. However, the OA composition exhibited statistically significant diurnal variation with more oxidized OA in the afternoon. The organic aerosol was highly oxidized, regardless of the source region. Total OA concentrations also varied little with time of day, suggesting that local sources had only a small effect on OA concentrations measured at Finokalia. The aerosol was transported for about one day before arriving at the site, corresponding to an OH exposure of approximately 4×1011 molecules cm-3 s. The constant extent of oxidation suggests that atmospheric aging results in a highly oxidized OA at these OH exposures, regardless of the aerosol source.

  13. Aged organic aerosol in the Eastern Mediterranean: the Finokalia Aerosol Measurement Experiment - 2008

    NASA Astrophysics Data System (ADS)

    Hildebrandt, L.; Engelhart, G. J.; Mohr, C.; Kostenidou, E.; Lanz, V. A.; Bougiatioti, A.; Decarlo, P. F.; Prevot, A. S. H.; Baltensperger, U.; Mihalopoulos, N.; Donahue, N. M.; Pandis, S. N.

    2010-05-01

    Aged organic aerosol (OA) was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2008 (FAME-2008), which was part of the EUCAARI intensive campaign of May 2008. The site at Finokalia is influenced by air masses from different source regions, including long-range transport of pollution from continental Europe. A quadrupole aerosol mass spectrometer (Q-AMS) was employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1), and to estimate the extent of oxidation of the organic aerosol. Factor analysis was used to gain insights into the processes and sources affecting the OA composition. The particles were internally mixed and liquid. The largest fraction of the dry NR-PM1 sampled was ammonium sulfate and ammonium bisulfate, followed by organics and a small amount of nitrate. The variability in OA composition could be explained with two factors of oxygenated organic aerosol (OOA) with differing extents of oxidation but similar volatility. Hydrocarbon-like organic aerosol (HOA) was not detected. There was no statistically significant diurnal variation in the bulk composition of NR-PM1 such as total sulfate or total organic aerosol concentrations. However, the OA composition exhibited statistically significant diurnal variation with more oxidized OA in the afternoon. The organic aerosol was highly oxidized, regardless of the source region. Total OA concentrations also varied little with source region, suggesting that local sources had only a small effect on OA concentrations measured at Finokalia. The aerosol was transported for about one day before arriving at the site, corresponding to an OH exposure of approximately 4×1011 molecules cm-3 s. The constant extent of oxidation suggests that atmospheric aging results in a highly oxidized OA at these OH exposures, regardless of the aerosol source.

  14. Ganges Valley Aerosol Experiment (GVAX) Final Campaign Report

    SciTech Connect

    Kotamarthi, VR

    2013-12-01

    In general, the Indian Summer Monsoon (ISM) as well as the and the tropical monsoon climate is influenced by a wide range of factors. Under various climate change scenarios, temperatures over land and into the mid troposphere are expected to increase, intensifying the summer pressure gradient differential between land and ocean and thus strengthening the ISM. However, increasing aerosol concentration, air pollution, and deforestation result in changes to surface albedo and insolation, potentially leading to low monsoon rainfall. Clear evidence points to increasing aerosol concentrations over the Indian subcontinent with time, and several hypotheses regarding the effect on monsoons have been offered. The Ganges Valley Aerosol Experiment (GVAX) field study aimed to provide critical data to address these hypotheses and contribute to developing better parameterizations for tropical clouds, convection, and aerosol-cloud interactions. The primary science questions for the mission were as follows:

  15. Results from simulated upper-plenum aerosol transport and aerosol resuspension experiments

    SciTech Connect

    Wright, A.L.; Pattison, W.L.

    1984-01-01

    Recent calculational results published as part of the Battelle-Columbus BMI-2104 source term study indicate that, for some LWR accident sequences, aerosol deposition in the reactor primary coolant system (PCS) can lead to significant reductions in the radionuclide source term. Aerosol transport and deposition in the PCS have been calculated in this study using the TRAP-MELT 2 computer code, which was developed at Battelle-Columbus; the status of validation of the TRAP-MELT 2 code has been described in an Oak Ridge National Laboratory (ORNL) report. The objective of the ORNL TRAP-MELT Validation Project, which is sponsored by the Fuel Systems Behavior Research Branch of the US Nuclear Regulatory Commission, is to conduct simulated reactor-vessel upper-plenum aerosol deposition and transport tests. The results from these tests will be used in the ongoing effort to validate TRAP-MELT 2. The TRAP-MELT Validation Project includes two experimental subtasks. In the Aerosol Transport Tests, aerosol transport in a vertical pipe is being studied; this geometry was chosen to simulate aerosol deposition and transport in the reactor-vessel upper-plenum. To date, four experiments have been performed; the results from these tests are presented in this paper. 7 refs., 4 figs., 4 tabs.

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

    SciTech Connect

    Davidovits, Paul

    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

  17. The Hohenpeissenberg aerosol characterization experiment (HAZE2002): Aerosol composition derived from mass spectrometry

    NASA Astrophysics Data System (ADS)

    Hock, N.; Berresheim, H.; Borrmann, S.; Poeschl, U.; Roempp, A.; Schneider, J.

    2003-04-01

    The HAZE Experiment was conducted between 17.05.2002 and 31.05.2002, at the meteorological observatory of the Deutsche Wetterdienst (DWD) at Hohenpeissenberg (47^o48'N,11^o02'E, 985m). The objective was to make essential progress in understanding of the physical and chemical properties of the atmospheric aerosol, in particular relating to the Gas-To-Particle-Conversion and the interaction with meteorological processes. The measurements included online mass spectrometric analysis using the Aerosol Mass Spectrometer (AMS), filter samples with GC analyses of organic compounds, particle size distribution (Electrical Low Pressure Impactor (ELPI), SMPS, OPC), as well as the total particle concentration (CPC). Additionally, several gas-phase substances were measured (e.g. Benzene, Acetone). The measurements obtained with the AMS show a strong variability of the aerosol composition. The non-refractory aerosol composition was dominated by nitrate, sulphate, and organics, whereas ammonium was surprisingly low. High number concentration of up to 14000 particles/cm^3 were observed. These particles mostly had diameters between 200 nm and 400 nm and were mainly composed of ammonium sulphate and ammonium nitrate. Various meteorological conditions allowed to study their influence on the aerosol. For example, on rainy days the concentrations of ammonium sulphate particles decreased, whereas the concentrations of ammonium nitrate particles increased.

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

    PubMed

    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. PMID:26233420

  19. Ganges Valley Aerosol Experiment: Science and Operations Plan

    SciTech Connect

    Kotamarthi, VR

    2010-06-21

    The Ganges Valley region is one of the largest and most rapidly developing sections of the Indian subcontinent. The Ganges River, which provides the region with water needed for sustaining life, is fed primarily by snow and rainfall associated with Indian summer monsoons. Impacts of changes in precipitation patterns, temperature, and the flow of the snow-fed rivers can be immense. Recent satellite-based measurements have indicated that the upper Ganges Valley has some of the highest persistently observed aerosol optical depth values. The aerosol layer covers a vast region, extending across the Indo-Gangetic Plain to the Bay of Bengal during the winter and early spring of each year. The persistent winter fog in the region is already a cause of much concern, and several studies have been proposed to understand the economic, scientific, and societal dimensions of this problem. During the INDian Ocean EXperiment (INDOEX) field studies, aerosols from this region were shown to affect cloud formation and monsoon activity over the Indian Ocean. This is one of the few regions showing a trend toward increasing surface dimming and enhanced mid-tropospheric warming. Increasing air pollution over this region could modify the radiative balance through direct, indirect, and semi-indirect effects associated with aerosols. The consequences of aerosols and associated pollution for surface insolation over the Ganges Valley and monsoons, in particular, are not well understood. The proposed field study is designed for use of (1) the ARM Mobile Facility (AMF) to measure relevant radiative, cloud, convection, and aerosol optical characteristics over mainland India during an extended period of 9–12 months and (2) the G-1 aircraft and surface sites to measure relevant aerosol chemical, physical, and optical characteristics in the Ganges Valley during a period of 6–12 weeks. The aerosols in this region have complex sources, including burning of coal, biomass, and biofuels; automobile

  20. The Indian ocean experiment: aerosol forcing obtained from satellite data

    NASA Astrophysics Data System (ADS)

    Rajeev, K.; Ramanathan, V.

    The tropical Indian Ocean provides an ideal and unique natural laboratory to observe and understand the role of anthropogenic aerosols in climate forcing. Since 1996, an international team of American, European and Indian scientists have been collecting aerosol, chemical and radiation data from ships and surface stations, which culminated in a multi-platform field experiment conducted during January to March of 1999. A persistent haze layer that spread over most of the northern Indian Ocean during wintertime was discovered. The layer, a complex mix of organics, black carbon, sulfates, nitrates and other species, subjects the lower atmosphere to a strong radiative heating and a larger reduction in the solar heating of the ocean. We present here the regional distribution of aerosols and the resulting clear sky aerosol radiative forcing at top-of-atmosphere (TOA) observed over the Indian Ocean during the winter months of 1997, 1998 and 1999 based on the aerosol optical depth (AOD) estimated using NOAA14-AVHRR and the TOA radiation budget data from CERES on board TRMM. Using the ratio of surface to TOA clear sky aerosol radiative forcing observed during the same period over the Indian Ocean island of Kaashidhoo (Satheesh and Ramanathan, 2000), the clear sky aerosol radiative forcing at the surface and the atmosphere are discussed. The regional maps of AVHRR derived AOD show abnormally large aerosol concentration during the winter of 1999 which is about 1.5 to 2 times larger than the AOD during the corresponding period of 1997 and 1998. A large latitudinal gradient in AOD is observed during all the three years of observation, with maximum AOD in the northern hemisphere. The diurnal mean clear sky aerosol forcing at TOA in the northern hemisphere Indian Ocean is in the range of -4 to -16 Wm -2 and had large spatio-temporal variations while in the southern hemisphere Indian Ocean it is in the range of 0 to -6Wm -2. The importance of integrating in-situ data with satellite

  1. Continuation of Lithium Aerosol Injection Experiments on NSTX

    NASA Astrophysics Data System (ADS)

    Mansfield, D. K.; Roquemore, A. L.; Kugel, H.; Maingi, R.; Irby, J.; Wang, Z.

    2009-11-01

    During the 2008 run campaign, a Li powder dropper was installed on NSTX that successfully injected up to 35 mg/s of Li aerosol into the SOL. Initial improvements in the plasma performance from these initial experiments warranted the installation of a second Li dropper for the 2009 campaign. Design improvements in the dropper have resulted in accurate control of the flux of Li powder injected. The improved duel-dropper system has injected lithium fluxes of from 30 - 140 mg/s. At the highest flux, plasmas of 950 kA with 6 MW off NBI auxiliary heating have been successfully operated. This flux corresponds to 2.5 x106 - 5.8 x106 aerosol particles/s and is stoichiometrically equivalent 80 - 187 Torr L/s of D2. Operation of the Li dropper and the effects of the Li aerosol on the plasma performance will be discussed.

  2. Complex Aerosol Experiment in Western Siberia (April - October 2013)

    NASA Astrophysics Data System (ADS)

    Matvienko, G. G.; Belan, B. D.; Panchenko, M. V.; Romanovskii, O. A.; Sakerin, S. M.; Kabanov, D. M.; Turchinovich, S. A.; Turchinovich, Yu. S.; Eremina, T. A.; Kozlov, V. S.; Terpugova, S. A.; Pol'kin, V. V.; Yausheva, E. P.; Chernov, D. G.; Zuravleva, T. B.; Bedareva, T. V.; Odintsov, S. L.; Burlakov, V. D.; Arshinov, M. Yu.; Ivlev, G. A.; Savkin, D. E.; Fofonov, A. V.; Gladkikh, V. A.; Kamardin, A. P.; Balin, Yu. S.; Kokhanenko, G. P.; Penner, I. E.; Samoilova, S. V.; Antokhin, P. N.; Arshinova, V. G.; Davydov, D. K.; Kozlov, A. V.; Pestunov, D. A.; Rasskazchikova, T. M.; Simonenkov, D. V.; Sklyadneva, T. K.; Tolmachev, G. N.; Belan, S. B.; Shmargunov, V. P.

    2016-06-01

    The primary project objective was to accomplish the Complex Aerosol Experiment, during which the aerosol properties should be measured in the near-ground layer and free atmosphere. Three measurement cycles were performed during the project implementation: in spring period (April), when the maximum of aerosol generation is observed; in summer (July), when atmospheric boundary layer height and mixing layer height are maximal; and in late summer - early autumn (October), when the secondary particle nucleation period is recorded. Numerical calculations were compared with measurements of fluxes of downward solar radiation. It was shown that the relative differences between model and experimental values of fluxes of direct and total radiation, on the average, do not exceed 1% and 3% respectively.

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

    NASA Astrophysics Data System (ADS)

    Hock, N.; Schneider, J.; Borrmann, S.; Römpp, A.; Moortgat, G.; Franze, T.; Schauer, C.; Pöschl, U.; Plass-Dülmer, C.; Berresheim, H.

    2007-06-01

    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 of optical and other sizing techniques (OPC, AMS, SMPS), an average refractive index of 1.40-1.45 was inferred for the measured rural aerosol

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

    NASA Astrophysics Data System (ADS)

    Hock, N.; Schneider, J.; Borrmann, S.; Römpp, A.; Moortgat, G.; Franze, T.; Schauer, C.; Pöschl, U.; Plass-Dülmer, C.; Berresheim, H.

    2008-02-01

    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. Online measurements included: Size-resolved chemical composition of submicron particles; total particle number concentrations and size distributions over the diameter range of 3 nm to 9 μm; gas-phase concentration of monoterpenes, CO, O3, OH, and H2SO4. 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: (23±39)% ammonium nitrate, (27±23)% ammonium sulfate, and (50±40)% organics (OM1). OM1 was closely correlated with PM1 (r2=0.9) indicating a near-constant ratio of non-refractory organics and inorganics. The average ratio of OM1 to OC2.5 was 2.1±1.4, indicating a high proportion of heteroelements in the organic fraction of the sampled rural aerosol. This is consistent with the high ratio of oxygenated organic aerosol (OOA) over hydrocarbon-like organic aerosol (HOA) inferred from the AMS results (4:1), and also with the high abundance of proteins (~3%) indicating a high proportion of primary biological material (~30%) in PM2.5. This finding was confirmed by low abundance of PAHs (<1 ng m-3) and EC (<1 μg m-3) in PM2.5 and detection of several secondary organic aerosol compounds (dicarboxylic acids) and their precursors (monoterpenes). New particle formation was observed almost

  5. Source term experiments project (STEP): aerosol characterization system

    SciTech Connect

    Schlenger, B.J.; Dunn, P.F.

    1985-01-01

    A series of four experiments is being conducted at Argonne National Laboratory's TREAT Reactor. They have been designed to provide some of the necessary data regarding magnitude and release rates of fission products from degraded fuel pins, physical and chemical characteristics of released fission products, and aerosol formation and transport phenomena. These are in-pile experiments, whereby the test fuel is heated by neutron induced fission and subsequent clad oxidation in steam environments that simulate as closely as practical predicted reactor accident conditions. The test sequences cover a range of pressure and fuel heatup rate, and include the effect of Ag/In/Cd control rod material.

  6. Aerosol Optical Properties During The SAMUM-2 Experiment

    NASA Astrophysics Data System (ADS)

    Toledano, C.; Freudenthaler, V.; Gross, S.; Seefeldner, M.; Gasteiger, J.; Garhammer, M.; Esselborn, M.; Wiegner, M.; Koepke, P.

    2009-03-01

    A field campaign of the Saharan Mineral Dust Experiment (SAMUM-2) took place in the Cape Verde islands in January-February 2008, to investigate the properties of long-range transported dust over the Atlantic. The Meteorological Institute of the University of Munich deployed a set of active and passive remote sensing instruments: one sun photometer, for the measurement of the direct sun irradiance and sky radiances; a broad-band UV radiometer; and 2 tropospheric lidar systems. The measurements were made in close cooperation with the other participating groups. During the measurement period the aerosol scenario over Cape Verde mostly consisted of a dust layer below 2 km and a smoke layer above 2 km height. The Saharan dust arrived in the site from the NE, whereas the smoke originated in the African equatorial region is transported from the SE. The aerosol load was also very variable over this area, with AOD (500 nm) ranging from 0.04 to 0.74. The optical properties of the layers are shown: extinction and particle depolarization ratio profiles at 3 wavelengths, as well as aerosol optical depth (in the range 340-1550 nm), Ångström exponent, size distribution and single scattering albedo.

  7. The polar ozone and aerosol measurement experiment (POAM II)

    SciTech Connect

    Bevilacqua, R.M.; Shettle, E.P.; Hornstein, J.S.

    1994-12-31

    The Polar Ozone and Aerosol Measurement experiment (POAM II), was launched on the SPOT 3 satellite on 25 September, 1993. POAM II is designed to measure the vertical profiles of the polar ozone, aerosols, water vapor, nitrogen dioxide, atmospheric density and temperature in the stratosphere and upper troposphere. It makes solar occultation measurements in nine channels defined by narrow-band filters. The field of view is 0.01 by 1.2 degrees, with an instantaneous vertical resolution of 0.6 km at the tangent point in the earth`s atmosphere. The SPOT 3 satellite is in a 98.7-degree inclined sun-synchronous orbit at an altitude of 833 km. From the measured transmissions, it is possible to determine the density profiles of aerosols, O{sub 3}, H{sub 2}O, and NO{sub 2}. Using the assumption of uniformly mixed oxygen, the authors are also able to determine the temperature. The authors present details of the POAM II instrument design, including the optical configuration, electronics and measurement accuracy. The authors also present preliminary results from the occultation measurements made to date.

  8. Seawater mesocosm experiments in the Arctic uncover differential transfer of marine bacteria to aerosols.

    PubMed

    Fahlgren, Camilla; Gómez-Consarnau, Laura; Zábori, Julia; Lindh, Markus V; Krejci, Radovan; Mårtensson, E Monica; Nilsson, Douglas; Pinhassi, Jarone

    2015-06-01

    Biogenic aerosols critically control atmospheric processes. However, although bacteria constitute major portions of living matter in seawater, bacterial aerosolization from oceanic surface layers remains poorly understood. We analysed bacterial diversity in seawater and experimentally generated aerosols from three Kongsfjorden sites, Svalbard. Construction of 16S rRNA gene clone libraries from paired seawater and aerosol samples resulted in 1294 sequences clustering into 149 bacterial and 34 phytoplankton operational taxonomic units (OTUs). Bacterial communities in aerosols differed greatly from corresponding seawater communities in three out of four experiments. Dominant populations of both seawater and aerosols were Flavobacteriia, Alphaproteobacteria and Gammaproteobacteria. Across the entire dataset, most OTUs from seawater could also be found in aerosols; in each experiment, however, several OTUs were either selectively enriched in aerosols or little aerosolized. Notably, a SAR11 clade OTU was consistently abundant in the seawater, but was recorded in significantly lower proportions in aerosols. A strikingly high proportion of colony-forming bacteria were pigmented in aerosols compared with seawater, suggesting that selection during aerosolization contributes to explaining elevated proportions of pigmented bacteria frequently observed in atmospheric samples. Our findings imply that atmospheric processes could be considerably influenced by spatiotemporal variations in the aerosolization efficiency of different marine bacteria. PMID:25682947

  9. Comparative studies of aerosol extinction measurements made by the SAM II and SAGE II satellite experiments

    NASA Technical Reports Server (NTRS)

    Yue, Glenn K.; Mccormick, M. P.; Chu, W. P.; Wang, P.; Osborn, M. T.

    1989-01-01

    Results from the Stratospheric Aerosol Measurement (SAM) II and Stratospheric Aerosol and Gas Experiment (SAGE) II are compared for measurement locations which are coincident in time and space. At 1.0 micron, the SAM II and SAGE II aerosol extinction profiles are similar within their measurement errors. In addition, sunrise and sunset aerosol extinction data at four different wavelengths are compared for occasions when the SAGE II and SAM II measurements are nearly coincident in space and about 12 hours apart.

  10. Stratospheric Aerosol and Gas Experiment (SAGE) II and III Aerosol Extinction Measurements in the Arctic Middle and Upper Troposphere

    NASA Technical Reports Server (NTRS)

    Treffeisen, R. E.; Thomason, L. W.; Strom, J.; Herber, A. B.; Burton, S. P.; Yamanouchi, T.

    2006-01-01

    In recent years, substantial effort has been expended toward understanding the impact of tropospheric aerosols on Arctic climate and chemistry. A significant part of this effort has been the collection and documentation of extensive aerosol physical and optical property data sets. However, the data sets present significant interpretive challenges because of the diverse nature of these measurements. Among the longest continuous records is that by the spaceborne Stratospheric Aerosol and Gas Experiment (SAGE) II. Although SAGE tropospheric measurements are restricted to the middle and upper troposphere, they may be able to provide significant insight into the nature and variability of tropospheric aerosol, particularly when combined with ground and airborne observations. This paper demonstrates the capacity of aerosol products from SAGE II and its follow-on experiment SAGE III to describe the temporal and vertical variations of Arctic aerosol characteristics. We find that the measurements from both instruments are consistent enough to be combined. Using this combined data set, we detect a clear annual cycle in the aerosol extinction for the middle and upper Arctic troposphere.

  11. Generation and characterization of aerosols and vapors for inhalation experiments.

    PubMed Central

    Tillery, M I; Wood, G O; Ettinger, H J

    1976-01-01

    Control of aerosol and vapor characteristics that affect the toxicity of inhaled contaminants often determines the methods of generating exposure atmospheres. Generation methods for aerosols and vapors are presented. The characteristics of the resulting exposure atmosphere and the limitations of the various generation methods are discussed. Methods and instruments for measuring the airborne contaminant with respect to various charcteristics are also described. PMID:797565

  12. A comparative study of aerosol extinction measurements made by the SAM II and SAGE satellite experiments

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Mccormick, M. P.; Chu, W. P.

    1984-01-01

    SAM II and SAGE are two satellite experiments designed to measure stratospheric aerosol extinction using the technique of solar occultation or limb extinction. Although each sensor is mounted aboard a different satellite, there are occasions when their measurement locations are nearly coincident, thereby providing opportunities for a measurement comparison. In this paper, the aerosol extinction profiles and daily contour plots for some of these events in 1979 are reported. The comparisons shown in this paper demonstrate that SAM II and SAGE are producing similar aerosol extinction profiles within their measurement errors and that since SAM II has been previously validated, these results show the validity of the SAGE aerosol measurements.

  13. The Stratospheric Aerosol and Gas Experiment III - International Space Station: Extending Long-Term Ozone and Aerosol Observations (Invited)

    NASA Astrophysics Data System (ADS)

    Eckman, R.; Zawodny, J. M.; Cisewski, M.; Gasbarre, J.; Flittner, D. E.; Hill, C.; Roell, M.; Moore, J. R.; Hernandez, G.; McCormick, M. P.

    2013-12-01

    The Stratospheric Aerosol and Gas Experiment III - International Space Station (SAGE III on ISS) will extend the global measurements of vertical profiles of ozone, aerosols, water vapor, nitrogen dioxide, and other trace gases begun with SAGE I in 1979, enabling the detection of long-term trends. SAGE III on ISS is the fourth in a series of instruments developed for monitoring these constituents in the stratosphere and troposphere. The SAGE III instrument is a moderate resolution spectrometer covering wavelengths from 290 nm to 1550 nm, using the heritage occultation technique, utilizing both the sun and the moon. Launch to ISS is planned for early 2015 aboard a Falcon 9 spacecraft. SAGE III will investigate the spatial and temporal variability of the measured species in order to determine their role in climatological processes, biogeochemical cycles, the hydrologic cycle, and atmospheric chemistry. It will characterize tropospheric, as well as stratospheric aerosols and upper tropospheric and stratospheric clouds, and investigate their effects on the Earth's environment including radiative, microphysical, and chemical interactions. The multi-decadal SAGE ozone and aerosol data sets have undergone intense scrutiny and are the international standard for accuracy and stability. SAGE data have been used to monitor the effectiveness of the Montreal Protocol. Amongst its key objectives will be to assess the state of the recovery in the distribution of ozone, to reestablish the aerosol measurements needed by both climate and ozone models, and to gain further insight into key processes contributing to ozone and aerosol variability. The ISS is ideal for Earth observing experiments; its mid-inclination orbit allows for a large range in latitude sampling and nearly continuous communications with payloads. In this presentation, we describe the SAGE III on ISS mission, its implementation, current status, and concentrate on its key science objectives.

  14. Fire aerosol experiment and comparisons with computer code predictions

    NASA Astrophysics Data System (ADS)

    Gregory, W. S.; Nichols, B. D.; White, B. W.; Smith, P. R.; Leslie, I. H.; Corkran, J. R.

    1988-08-01

    Los Alamos National Laboratory, in cooperation with New Mexico State University, has carried on a series of tests to provide experimental data on fire-generated aerosol transport. These data will be used to verify the aerosol transport capabilities of the FIRAC computer code. FIRAC was developed by Los Alamos for the U.S. Nuclear Regulatory Commission. It is intended to be used by safety analysts to evaluate the effects of hypothetical fires on nuclear plants. One of the most significant aspects of this analysis deals with smoke and radioactive material movement throughout the plant. The tests have been carried out using an industrial furnace that can generate gas temperatures to 300 C. To date, we have used quartz aerosol with a median diameter of about 10 microns as the fire aerosol simulant. We also plan to use fire-generated aerosols of polystyrene and polymethyl methacrylate (PMMA). The test variables include two nominal gas flow rates (150 and 300 cu ft/min) and three nominal gas temperatures (ambient, 150 C, and 300 C). The test results are presented in the form of plots of aerosol deposition vs length of duct. In addition, the mass of aerosol caught in a high-efficiency particulate air (HEPA) filter during the tests is reported. The tests are simulated with the FIRAC code, and the results are compared with the experimental data.

  15. Aerosol Effects on Radiation and Climate: Column Closure Experiments with Towers, Aircraft, and Satellites

    NASA Technical Reports Server (NTRS)

    Russell, Philip B.

    1994-01-01

    Many theoretical studies have shown that anthropogenic aerosol particles can change the radiation balance in an atmospheric column and might thereby exert a significant effect on the Earth's climate. In particular, recent calculations have shown that sulfate particles from anthropogenic combustion may already exert a cooling influence on the Earth that partially offsets the warming caused by the greenhouse gases from the same combustion. Despite the potential climatic importance of anthropogenic aerosols, simultaneous measurements of anthropogenic aerosol properties and their effect on atmospheric radiation have been very rare. Successful comparisons of measured radiation fields with those calculated from aerosol measurements - now referred to as column closure comparisons - are required to improve the accuracy and credibility of climate predictions. This paper reviews the column closure experiment performed at the Mt. Sutro Tower in San Francisco in 1975, in which elevated radiometers measured the change in Earth-plus-atmosphere albedo caused by an aerosol layer, while a lidar, sunphotometer, nephelometer, and other radiometers measured properties of the responsible aerosol. The time-dependent albedo calculated from the measured aerosol properties agreed with that measured by the tower radiometers. Also presented are designs for future column closure studies using radiometers and aerosol instruments on the ground, aircraft, and satellites. These designs draw upon algorithms and experience developed in the Sutro Tower study, as well as more recent experience with current measurement and analysis capabilities.

  16. Remote Sensing of Spectral Aerosol Properties: A Classroom Experience

    NASA Technical Reports Server (NTRS)

    Levy, Robert C.; Pinker, Rachel T.

    2006-01-01

    Bridging the gap between current research and the classroom is a major challenge to today s instructor, especially in the sciences where progress happens quickly. NASA Goddard Space Flight Center and the University of Maryland teamed up in designing a graduate class project intended to provide a hands-on introduction to the physical basis for the retrieval of aerosol properties from state-of-the-art MODIS observations. Students learned to recognize spectral signatures of atmospheric aerosols and to perform spectral inversions. They became acquainted with the operational MODIS aerosol retrieval algorithm over oceans, and methods for its evaluation, including comparisons with groundbased AERONET sun-photometer data.

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

    NASA Technical Reports Server (NTRS)

    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.

  18. Comparison of Aerosol Single Scattering Albedos Derived by Diverse Techniques In Two North Atlantic Experiments

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Redemann, J.; Schmid, B.; Bergstrom, R. W.; Livingston, J. M.; McIntosh, D. M.; Ramirez, S. A.; Hartley, S.; Hobbs, P. V.; Quinn, P. K.

    2002-01-01

    Aerosol single scattering albedo omega (the ratio of scattering to extinction) is important in determining aerosol climatic effects, in explaining relationships between calculated and measured radiative fluxes, and in retrieving aerosol optical depths from satellite radiances. Recently, two experiments in the North Atlantic region, the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) and the Second Aerosol Characterization Experiment (ACE-2), determined aerosol omega by a variety of techniques. The techniques included fitting of calculated to measured radiative fluxes; retrievals of omega from skylight radiances; best fits of complex refractive index to profiles of backscatter extinction, and size distribution; and in situ measurements of scattering and absorption at the surface and aloft. Both TARFOX and ACE-2 found a fairly wide range of values for omega at midvisable wavelengths approx. 550 nm, with omega(sub midvis) greater than or equal to 0.85 and less than or equal to 0.99 for the marine aerosol impacted by continental pollution. Frequency distributions of omega could usually be approximated by lognormals in omega(sub max) - omega, with some occurrence of bimodality, suggesting the influence of different aerosol sources or processing. In both TARFOX and ACE-2, closure tests between measured and calculated radiative fluxes yielded best-fit values of omega(sub midvis) 0.90 +/- 0.04 for the polluted boundary layer. Although these results have the virtue of describing the column aerosol unperturbed by sampling, they are subject to questions about representativeness and other uncertainties (e.g., thermal offsets, unknown gas absorption) The other techniques gave larger values for omega(sub midvis) for the polluted boundary layer, with a typical result of omega(sub midvis) = 0.95 +/- 0.04. Current uncertainties in omega are large in terms of climate effects More tests are needed of the consistency among different methods and of

  19. A Global Aerosol Model Forecast for the ACE-Asia Field Experiment

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Ginoux, Paul; Lucchesi, Robert; Huebert, Barry; Weber, Rodney; Anderson, Tad; Masonis, Sarah; Blomquist, Byron; Bandy, Alan; Thornton, Donald

    2003-01-01

    We present the results of aerosol forecast during the Aerosol Characterization Experiment (ACE-Asia) field experiment in spring 2001, using the Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model and the meteorological forecast fields from the Goddard Earth Observing System Data Assimilation System (GEOS DAS). The aerosol model forecast provides direct information on aerosol optical thickness and concentrations, enabling effective flight planning, while feedbacks from measurements constantly evaluate the model, making successful model improvements. We verify the model forecast skill by comparing model predicted total aerosol extinction, dust, sulfate, and SO2 concentrations with those quantities measured by the C-130 aircraft during the ACE-Asia intensive operation period. The GEOS DAS meteorological forecast system shows excellent skills in predicting winds, relative humidity, and temperature for the ACE-Asia experiment area as well as for each individual flight, with skill scores usually above 0.7. The model is also skillful in forecast of pollution aerosols, with most scores above 0.5. The model correctly predicted the dust outbreak events and their trans-Pacific transport, but it constantly missed the high dust concentrations observed in the boundary layer. We attribute this missing dust source to the desertification regions in the Inner Mongolia Province in China, which have developed in recent years but were not included in the model during forecasting. After incorporating the desertification sources, the model is able to reproduce the observed high dust concentrations at low altitudes over the Yellow Sea. Two key elements for a successful aerosol model forecast are correct source locations that determine where the emissions take place, and realistic forecast winds and convection that determine where the aerosols are transported. We demonstrate that our global model can not only account for the large

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

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

    NASA Technical Reports Server (NTRS)

    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).

  2. Characterizing the impact of urban emissions on regional aerosol particles; airborne measurements during the MEGAPOLI experiment

    NASA Astrophysics Data System (ADS)

    Freney, E. J.; Sellegri, K.; Canonaco, F.; Colomb, A.; Borbon, A.; Michoud, V.; Doussin, J.-F.; Crumeyrolle, S.; Amarouch, N.; Pichon, J.-M.; Prévôt, A. S. H.; Beekmann, M.; Schwarzenböeck, A.

    2013-09-01

    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 formation of OA

  3. Characterizing the impact of urban emissions on regional aerosol particles: airborne measurements during the MEGAPOLI experiment

    NASA Astrophysics Data System (ADS)

    Freney, E. J.; Sellegri, K.; Canonaco, F.; Colomb, A.; Borbon, A.; Michoud, V.; Doussin, J.-F.; Crumeyrolle, S.; Amarouche, N.; Pichon, J.-M.; Bourianne, T.; Gomes, L.; Prevot, A. S. H.; Beekmann, M.; Schwarzenböeck, A.

    2014-02-01

    The MEGAPOLI (Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation) 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 on the non-refractory submicron aerosol species. The mass concentration of black carbon (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), BC, 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 of different organic aerosol species (LV-OOA, SV-OOA, and HOA) illustrate that the increase in OA is a result of secondary organic aerosol (SOA) formation. Within Paris the changes in the ΔOA / ΔCO are similar to those observed during other studies in London, Mexico City, and in New England, USA. Using the measured SOA volatile organic compounds (VOCs) species together with organic aerosol formation

  4. ARM Cloud Aerosol Precipitation Experiment (ACAPEX) Science Plan

    SciTech Connect

    Leung, L. R.; Prather, K.; Ralph, R.; Rosenfeld, D.; Spackman, R.; DeMott, P.; Fairall, C.; Fan, J.; Hagos, S.; Hughes, M.; Long, C.; Rutledge, S.; Waliser, D.; Wang, H.

    2014-09-01

    The western U.S. receives precipitation predominantly during the cold season when storms approach from the Pacific Ocean. The snowpack that accumulates during winter storms provides about 70-90% of water supply for the region. Understanding and modeling the fundamental processes that govern the large precipitation variability and extremes in the western U.S. is a critical test for the ability of climate models to predict the regional water cycle, including floods and droughts. Two elements of significant importance in predicting precipitation variability in the western U.S. are atmospheric rivers and aerosols. Atmospheric rivers (ARs) are narrow bands of enhanced water vapor associated with the warm sector of extratropical cyclones over the Pacific and Atlantic oceans. Because of the large lower-tropospheric water vapor content, strong atmospheric winds and neutral moist static stability, some ARs can produce heavy precipitation by orographic enhancement during landfall on the U.S. West Coast. While ARs are responsible for a large fraction of heavy precipitation in that region during winter, much of the rest of the orographic precipitation occurs in post-frontal clouds, which are typically quite shallow, with tops just high enough to pass the mountain barrier. Such clouds are inherently quite susceptible to aerosol effects on both warm rain and ice precipitation-forming processes.

  5. Aerosol Properties over the Indo-Gangetic Plain: A Mesoscale Perspective from the TIGERZ Experiment

    NASA Technical Reports Server (NTRS)

    Giles, David M.; Holben, Brent N.; Tripathi, Sachchida; Eck, Thomas F.; Newcomb, W. Wayne; Slutsker, Ilya; Dickerson, Russell R.; Thompson, Anne M.; Mattoo, Shana; Wang, Sheng-Hsiang; Singh, Remesh P.; Sinyuk, Aliaksandr; Schafer, Joel S.

    2011-01-01

    High aerosol loading over the northern Indian subcontinent can result in poor air quality leading to human health consequences and climate perturbations. The international 2008 TIGERZ experiment intensive operational period (IOP) was conducted in the Indo \\Gangetic Plain (IGP) around the industrial city of Kanpur (26.51degN, 80.23deg E), India, during the premonsoon (April-June). Aerosol Robotic Network (AERONET) Sun photometers performed frequent measurements of aerosol properties at temporary sites distributed within an area covering 50 sq km around Kanpur to characterize pollution and dust in a region where complex aerosol mixtures and semi \\bright surface effects complicate satellite retrieval algorithms. TIGERZ IOP Sun photometers quantified aerosol optical depth (AOD) increases up to 0.10 within and downwind of the city, with urban emissions accounting for 10 C20% of the IGP aerosol loading on deployment days. TIGERZ IOP area \\averaged volume size distribution and single scattering albedo retrievals indicated spatially homogeneous, uniformly sized, spectrally absorbing pollution and dust particles. Aerosol absorption and size relationships were used to categorize black carbon and dust as dominant absorbers and to identify a third category in which both black carbon and dust dominate absorption.Moderate Resolution Imaging Spectroradiometer (MODIS) AOD retrievals with the lowest quality assurance (QA > or = 0) flags were biased high with respect to TIGERZ IOP area \\averaged measurements. MODIS AOD retrievals with QA 0 had moderate correlation (R(sup 2) = 0.52-69) with the Kanpur AERONET site, whereas retrievals with QA > 0 were limited in number. Mesoscale \\distributed Sun photometers quantified temporal and spatial variability of aerosol properties, and these results were used to validate satellite retrievals.

  6. Aerosol properties over the Indo-Gangetic Plain: A mesoscale perspective from the TIGERZ experiment

    NASA Astrophysics Data System (ADS)

    Giles, David M.; Holben, Brent N.; Tripathi, Sachchida N.; Eck, Thomas F.; Newcomb, W. Wayne; Slutsker, Ilya; Dickerson, Russell R.; Thompson, Anne M.; Mattoo, Shana; Wang, Sheng-Hsiang; Singh, Remesh P.; Sinyuk, Aliaksandr; Schafer, Joel S.

    2011-09-01

    High aerosol loading over the northern Indian subcontinent can result in poor air quality leading to human health consequences and climate perturbations. The international 2008 TIGERZ experiment intensive operational period (IOP) was conducted in the Indo-Gangetic Plain (IGP) around the industrial city of Kanpur (26.51°N, 80.23°E), India, during the premonsoon (April-June). Aerosol Robotic Network (AERONET) Sun photometers performed frequent measurements of aerosol properties at temporary sites distributed within an area covering ˜50 km2 around Kanpur to characterize pollution and dust in a region where complex aerosol mixtures and semi-bright surface effects complicate satellite retrieval algorithms. TIGERZ IOP Sun photometers quantified aerosol optical depth (AOD) increases up to ˜0.10 within and downwind of the city, with urban emissions accounting for ˜10-20% of the IGP aerosol loading on deployment days. TIGERZ IOP area-averaged volume size distribution and single scattering albedo retrievals indicated spatially homogeneous, uniformly sized, spectrally absorbing pollution and dust particles. Aerosol absorption and size relationships were used to categorize black carbon and dust as dominant absorbers and to identify a third category in which both black carbon and dust dominate absorption. Moderate Resolution Imaging Spectroradiometer (MODIS) AOD retrievals with the lowest quality assurance (QA ≥ 0) flags were biased high with respect to TIGERZ IOP area-averaged measurements. MODIS AOD retrievals with QA ≥ 0 had moderate correlation (R2 = 0.52-0.69) with the Kanpur AERONET site, whereas retrievals with QA > 0 were limited in number. Mesoscale-distributed Sun photometers quantified temporal and spatial variability of aerosol properties, and these results were used to validate satellite retrievals.

  7. Chemical Characterization of the Aerosol During the CLAMS Experiment Using Aircraft and Ground Stations

    NASA Astrophysics Data System (ADS)

    Castanho, A. D.; Martins, J.; Artaxo, P.; Hobbs, P. V.; Remer, L.; Yamasoe, M.; Fattori, A.

    2002-05-01

    During the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment Nuclepore filters were collected in two ground stations and aboard the University of Wasghington's Convair 580 Reserarch Aircraft. The two ground stations were chosen in strategic positions to characterize the chemical composition, the mass concentration, black carbon (BC) content, and the absorption properties of the aerosol particles at the surface level. One of the stations was located at the Cheasapeake lighthouse (25 km from the coast) and the other one was located at the Wallops Island. Aerosol particles where collected in two stages, fine (d<2.5um) and coarse mode (2.5experiment. Airborne samples were also collected on the UW Convair 580 Aircraft. The aircraft samples where used to characterize the elemental composition, mass concentration, BC content, and absorption properties of the aerosol in the atmospheric column in the CLAMS Experiment area. Some of the filters were also submitted to Scanning Electron Microscopy analysis. The particulate matter mass for all the samples were obtained gravimetrically. The concentration of black carbon in the fine filters was optically determined by a broadband reflectance technique. The spectral (from UV to near IR) reflectance in the fine and coarse mode filter were also obtained with a FieldSpec ASD spectrometer. Aerosol elemental characterization (Na through Pb) was obtained by the PIXE (Particle induced X ray emission) analyses of the nuclepore filters. The sources of the aerosol measured at the ground stations were estimated by principal component analyses mainly in the Wallops Island, where a longer time series was collected. One of the main urban components identified in the aerosol during the experiment was sulfate. Black carbon

  8. The Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment SALTRACE 2013 - Overview and Early Results (Invited)

    NASA Astrophysics Data System (ADS)

    Weinzierl, B.; Ansmann, A.; Reitebuch, O.; Freudenthaler, V.; Müller, T.; Kandler, K.; Althausen, D.; Busen, R.; Dollner, M.; Dörnbrack, A.; Farrell, D. A.; Gross, S.; Heimerl, K.; Klepel, A.; Kristensen, T. B.; Mayol-Bracero, O. L.; Minikin, A.; Prescod, D.; Prospero, J. M.; Rahm, S.; Rapp, M.; Sauer, D. N.; Schaefler, A.; Toledano, C.; Vaughan, M.; Wiegner, M.

    2013-12-01

    Mineral dust is an important player in the global climate system. In spite of substantial progress in the past decade, many questions in our understanding of the atmospheric and climate effects of mineral dust remain open such as the change of the dust size distribution during transport across the Atlantic Ocean and the associated impact on the radiation budget, the role of wet and dry dust removal mechanisms during transport, and the complex interaction between mineral dust and clouds. To close gaps in our understanding of mineral dust in the climate system, the Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE: http://www.pa.op.dlr.de/saltrace) was conducted in June/July 2013. SALTRACE is a German initiative combining ground-based and airborne in-situ and lidar measurements with meteorological data, long-term measurements, satellite remote sensing and modeling. During SALTRACE, the DLR research aircraft Falcon was based on Sal, Cape Verde, between 11 and 17 June, and on Barbados between 18 June and 11 July 2013. The Falcon was equipped with a suite of in-situ instruments for the measurement of microphysical and optical aerosol properties and with a nadir-looking 2-μm wind lidar. Ground-based lidar and in-situ instruments were deployed in Barbados and Puerto Rico. Mineral dust from several dust outbreaks was measured by the Falcon between Senegal and Florida. On the eastern side of the Atlantic, dust plumes extended up to 6 km altitude, while the dust layers in the Caribbean were mainly below 4.5 km. The aerosol optical thickness of the dust outbreaks studied ranged from 0.2 to 0.6 at 500 nm in Barbados. Highlights during SALTRACE included the sampling of a dust plume in the Cape Verde area on 17 June which was again measured with the same instrumentation on 21 and 22 June near Barbados. The event was also captured by the ground-based lidar and in-situ instrumentation. Another highlight was the formation of tropical storm

  9. Comparison of Aerosol Single Scattering Albedos Derived By Diverse Techniques in Two North Atlantic Experiments

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Redemann, J.; Schmid, B.; Bergstrom, R. W.; Livingston, J. M.; McIntosh, D. M.; Hartley, S.; Hobbs, P. V.; Quinn, P. K.; Carrico, C. M.; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    Aerosol single scattering albedo w (the ratio of scattering to extinction) is important in determining aerosol climatic effects, in explaining relationships between calculated and measured radiative fluxes, and in retrieving aerosol optical depths from satellite radiances. Recently, two experiments in the North Atlantic region, TARFOX and ACE-2, determined aerosol w by a variety of techniques. The techniques included fitting of calculated to measured fluxes; retrievals of w from skylight radiances; best fits of complex refractive index to profiles of backscatter, extinction, and size distribution; and in situ measurements of scattering and absorption at the surface and aloft. Both TARFOX and ACE-2 found a fairly wide range of values for w at midvisible wavelengths, with 0.85 less than wmidvis less than 0.99 for the marine aerosol impacted by continental pollution. Frequency distributions of w could usually be approximated by lognormals in wmax-w, with some occurrence of bimodality, suggesting the influence of different aerosol sources or processing. In both TARFOX and ACE-2, closure tests between measured and calculated radiative fluxes yielded best-fit values of wmidvis of 0.90+/-0.04 for the polluted boundary layer. Although these results have the virtue of describing the column aerosol unperturbed by sampling, they are subject to questions about representativeness and possible artifacts (e.g., unknown gas absorption). The other techniques gave larger values for wmidvis for the polluted boundary layer, with a typical result of wmidvis = 0.95+/-0.04, Current uncertainties in vv are large in terms of climate effects. More tests are needed of the consistency among different methods and of humidification effects on w.

  10. Elemental composition of aerosols in fourteen experiments of the Cloud Condensation Nuclei Workshop

    NASA Technical Reports Server (NTRS)

    Mach, W. H.; Hucek, R. R.

    1981-01-01

    Aeosols were collected with two Ci impactors and analyzed with proton induced X-ray emission (PIXE) for chemical composition and to detect if contamination was present. One of the impactors sampled the generated aerosols; the other impactor sampled droplets from a diffusion cloud chamber. The purpose of the experiments was to test the feasibility of a study of the transfer of chemical elements from the fine particle sizes to the coarse particle sizes, after CCN are activated and cloud droplets are formed. The data indicated that sulfur-containing aerosols did exhibit the expected transfer.

  11. A study on characterization of stratospheric aerosol and gas parameters with the spacecraft solar occultation experiment

    NASA Technical Reports Server (NTRS)

    Chu, W. P.

    1977-01-01

    Spacecraft remote sensing of stratospheric aerosol and ozone vertical profiles using the solar occultation experiment has been analyzed. A computer algorithm has been developed in which a two step inversion of the simulated data can be performed. The radiometric data are first inverted into a vertical extinction profile using a linear inversion algorithm. Then the multiwavelength extinction profiles are solved with a nonlinear least square algorithm to produce aerosol and ozone vertical profiles. Examples of inversion results are shown illustrating the resolution and noise sensitivity of the inversion algorithms.

  12. MELCOR 1.8.2 assessment: Aerosol experiments ABCOVE AB5, AB6, AB7, and LACE LA2

    SciTech Connect

    Souto, F.J.; Haskin, F.E.; Kmetyk, L.N.

    1994-10-01

    The MELCOR computer code has been used to model four of the large-scale aerosol behavior experiments conducted in the Containment System Test Facility (CSTF) vessel. Tests AB5, AB6 and AB7 of the ABCOVE program simulate the dry aerosol conditions during a hypothetical severe accident in an LMFBR. Test LA2 of the LACE program simulates aerosol behavior in a condensing steam environment during a postulated severe accident in an LWR with failure to isolate the containment. The comparison of code results to experimental data show that MELCOR is able to correctly predict most of the thermal-hydraulic results in the four tests. MELCOR predicts reasonably well the dry aerosol behavior of the ABCOVE tests, but significant disagreements are found in the aerosol behavior modelling for the LA2 experiment. These results tend to support some of the concerns about the MELCOR modelling of steam condensation onto aerosols expressed in previous works. During these analyses, a limitation in the MELCOR input was detected for the specification of the aerosol parameters for more than one component. A Latin Hypercube Sampling (LHS) sensitivity study of the aerosol dynamic constants is presented for test AB6. The study shows the importance of the aerosol shape factors in the aerosol deposition behavior, and reveals that MELCOR input/output processing is highly labor intensive for uncertainty and sensitivity analyses based on LHS.

  13. Aerosol and melt chemistry in the ACE molten core-concrete interaction experiments

    SciTech Connect

    Fink, J.K.; Thompson, D.H.; Spencer, B.W.; Sehgal, B.R.

    1995-01-01

    Experimental results are discussed from the internationally sponsored Advanced Containment Experiments (ACE) Program on the melt behavior and aerosols released during the interaction of molten reactor core material with concrete. A broad range of parameters were addressed in the experimental program: Seven large-scale tests were performed using four types of concrete (siliceous, limestone/sand, serpentine, and limestone) and a range of metal oxidations for both boiling water and pressurized waster reactor core debris. The release aerosols contained mainly constitutents of the concrete. In the tests with metal and limestone/sand siliceous concrete, silicon compounds comprised 50% or more of the aerosol mass. Releases of uranium and low-volatility fission-product elements were small in all tests. Releases of tellurium and neutron absorber materials (silver, indium, and boron from boron carbide) were high.

  14. Analytical pyrolysis experiments of Titan aerosol analogues in preparation for the Cassini Huygens mission

    NASA Technical Reports Server (NTRS)

    Ehrenfreund, P.; Boon, J. J.; Commandeur, J.; Sagan, C.; Thompson, W. R.; Khare, B.

    1995-01-01

    Comparative pyrolysis mass spectrometric data of Titan aerosol analogs, called 'tholins', are presented. The Titan tholins were produced in the laboratory at Cornell by irradiation of simulated Titan atmospheres with high energy electrons in plasma discharge. Mass-spectrometry measurements were performed at FOM of the solid phase of various tholins by Curie-point pyrolysis Gas-Chromatography/Mass-Spectrometry (GCMS) and by temperature resolved in-source Pyrolysis Mass-Spectrometry to reveal the composition and evolution temperature of the dissociation products. The results presented here are used to further define the ACP (Aerosol Collector Pyrolyser)-GCMS experiment and provide a basis for modelling of aerosol composition on Titan and for the iterpretation of Titan atmosphere data from the Huygens probe in the future.

  15. Real-time aerosol data assimilation experiments during the 2014 FRAPPE/DISCOVER-AQ field mission

    NASA Astrophysics Data System (ADS)

    Pierce, R. B.

    2014-12-01

    The Front Range Air Pollution and Photochemistry Experiment (FRAPPE) and Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field missions were conducted over the Front Range of Colorado during July and August, 2014. Prior to, and during this period, much of the continental US were impacted by smoke from Canadian and Pacific Northwest wildfires, including the Front Range. This study assesses the impact of real-time assimilation of Aerosol Optical Depth (AOD) retrievals from the MODIS instrument on NASA's Terra and Aqua satellites within the Real-time Air Quality Modeling System (RAQMS) through comparisons of aerosol predictions with observations for two parallel forecasts that were conducted during FRAPPE/DISCOVER-AQ, one with and one without MODIS AOD assimilation. Results of these real-time assimilation experiments demonstrate that assimilation of MODIS AOD improves the prediction of large-scale smoke events such as those that occurred during July and August, 2014. These assimilation experiments help to guide the development of future operational aerosol forecasting systems within the NOAA Environmental Modeling System (NEMS) Global Forecasting System (GFS) Aerosol Component (NGAC) under development at the National Centers for Environmental Prediction (NCEP).

  16. The hydrological assessment of aerosol effects by the idealized airborne cloud seeding experiment

    NASA Astrophysics Data System (ADS)

    Lee, K.; Lee, B.; Chae, S.; Lee, C.; Choi, Y.

    2012-12-01

    The main source of aerosols over East Asia including the Korean Peninsula is the anthropogenic emission of atmospheric pollutants transported from Chinese industrial areas. For this reason, the researches of aerosol effects are very active in East Asian countries. In case of South Korea, aircraft measurement campaigns and airborne cloud seeding experiments for the meteorological and environmental research have been conducted over the local area of Korean Peninsula since the year of 2010. This project is related with the weather modification research to build up strategies for the regulation or enhancement of precipitation and snowpack for a severe drought in South Korea during a winter season. For this study, the aerosol effect on precipitation by the airborne cloud seeding was simulated using WRF-CHEM model with RADM2/MADE,SORGAM modules. Emission data of 10000μg/(m2s) of unspeciated primary PM2.5 were input at 0.5km altitude for aerosol scenario cases which is the height of airborne cloud seeding experiment. For the control run, the original WRF model with no chemistry/aerosol modules was used. Also, the hydrological model, SWAT (Soil and Water Assessment Tool, USDA/ARS) is incorporated to evaluate this aerosol effects hydrologically for the enhancement of precipitation or snowfall from the results of WRF-CHEM model. The target area is the Andong dam basin (1,584 km2) which is known as one of the important water resources in southern part of South Korea. The date was chosen based on the conditions of airborne cloud seeding experiment (RH>50%, Low Temp.<-3°C, Wind Speeds<5m/s, etc). During the 24 forecasting hour, the aerosol scenario case showed more amounts of accumulated precipitation (about 12%) than those of control run. According to the analysis of SWAT, the enhancement of precipitation in aerosol scenario cases of WRF-CHEM model could influence the increase of about 1.0×106m3 water resources when we assumed the 10% of effective area over the Andong dam

  17. The Saharan Aerosol Long-range Transport and Aerosol-Cloud Interaction Experiment (SALTRACE 2013) - An overview

    NASA Astrophysics Data System (ADS)

    Weinzierl, Bernadett; Ansmann, Albert; Reitebuch, Oliver; Freudenthaler, Volker; Müller, Thomas; Kandler, Konrad; Althausen, Dietrich; Chouza, Fernando; Dollner, Maximilian; Farrell, David; Groß, Silke; Heinold, Bernd; Kristensen, Thomas B.; Mayol-Bracero, Olga L.; Omar, Ali; Prospero, Joseph; Sauer, Daniel; Schäfler, Andreas; Toledano, Carlos; Tegen, Ina

    2015-04-01

    Saharan mineral dust is regularly transported over long distances impacting air quality, health, weather and climate thousands of kilometers downwind of the Sahara. During transport, the properties of mineral dust may be modified thereby changing the associated impact on the radiation budget. Although mineral dust is of key importance for the climate system many questions such as the change of the dust size distribution during long-range transport, the role of wet and dry removal mechanisms, and the complex interaction between mineral dust and clouds remain open. To investigate the aging and modification of Saharan mineral dust during long-range transport across the Atlantic Ocean, the Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE: http://www.pa.op.dlr.de/saltrace) was conducted in June/July 2013. SALTRACE was designed as a closure experiment combining ground-based lidar, in-situ and sun photometer instruments deployed on Cape Verde, Barbados and Puerto Rico, with airborne measurements of the DLR research aircraft Falcon, satellite observations and model simulations. During SALTRACE, mineral dust from five dust outbreaks was studied under different atmospheric conditions and a unique data set on the chemical, microphysical and optical properties of aged mineral dust was gathered. For the first time, Lagrangian sampling of a dust plume in the Cape Verde area on 17 June 2013 which was again measured with the same instrumentation on 21 and 22 June 2013 near Barbados was realized. Further highlights of SALTRACE include the formation and evolution of tropical storm Chantal in a dusty environment and the interaction of dust with mixed-phase clouds. In our presentation, we give an overview of the SALTRACE study, discuss the meteorological situation and the dust transport during SALTRACE and highlight selected results from SALTRACE.

  18. Ground-based aerosol characterization during the South American Biomass Burning Analysis (SAMBBA) field experiment

    NASA Astrophysics Data System (ADS)

    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 &cong

  19. Aerosol hygroscopicity and cloud droplet activation of extracts of filters from biomass burning experiments

    NASA Astrophysics Data System (ADS)

    Carrico, Christian M.; Petters, Markus D.; Kreidenweis, Sonia M.; Collett, Jeffrey L.; Engling, Guenter; Malm, William C.

    2008-04-01

    In this laboratory closure study, we compare sub- and supersaturated water uptake properties for aerosol particles possessing a range of hygroscopicity. Measurements for water sub-saturated conditions used a hygroscopic tandem differential mobility analyzer (HTDMA). Simultaneously, measurements of particle critical supersaturation were conducted on the same sample stream with a continuous flow cloud condensation nuclei (CCN) counter. For these experiments, we used filter-collected samples of biomass smoke generated in the combustion of two common wildland fire fuels, western sagebrush and Alaskan duff core. Extractions of separate sections of the filter were performed using two solvents, ultrapure water and methanol. The extracts were subsequently atomized, producing aerosols having a range of hygroscopic responses. HTDMA and CCN measurements were fit to a single-parameter model of water uptake, in which the fit parameter is denoted κ, the hygroscopicity parameter. Here, for the four extracts we observed mean values of the hygroscopicity parameter of 0.06 < κ < 0.30, similar to the range found previously for numerous pure organic compounds. Particles generated from the aqueous extracts of the filters had consistently larger κ than methanol extracts, while western sagebrush extract aerosols κ exceeded those from Alaskan duff core. HTDMA- and CCN-derived values of κ for each experiment agreed within approximately 20%. Applicability of the κ-parameterization to other multicomponent aerosols relevant to the atmosphere remains to be tested.

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  1. Dust and polluted aerosol impacts on diazotrophy during a mesocosm experiment in the Eastern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Rahav, Eyal; Herut, Barak; Liu, Hongbin; Guo, Cui; Cheung, Isaac; Psarra, Stella; Lagaria, Anna; Tsiola, Anastasia; Tsagaraki, Tanya; Pitta, Paraskevi; Mulholland, Margaret; Berman-Frank, Ilana

    2014-05-01

    Atmospheric inputs of nutrients via dust and aerosols to the surface ocean layer are considered to contribute greatly to dinitrogen (N2) fixation and to primary productivity. N2 fixation rates in the Mediterranean Sea are typically low and the parameters limiting this process are still unclear. Addition of dust analogs to a mesocosm experiment in the Western Mediterranean Sea (DUNE) enhanced N2 fixation by 3 to 5 fold. However, in the Eastern Mediterranean Sea, an area highly exposed to Saharan dust and aerosol, the impact of these inputs on N2 fixation from onboard microcosm experiment are unclear and inconclusive. We examined the influence of Saharan dust (1.6 mg L-1) and polluted aerosol (1 mg L-1) additions on diazotroph populations and N2 fixation rates in nine 3 m3 mesocosms (MESOAQUA project) using the enriched seawater method of 15N uptake. The enrichments induced an immediate 2-4 fold increase in N2 fixation (measured from 6 to 48 h after enrichments). After 4 days, N2 fixation rates returned to their background level and no significant change was observed relative to the control mesocosms. The increase in N2 fixation rates were reflected in the differential composition of diazotrophs. Dust enrichment enhanced the abundance of the filamentous cyanobacterium Trichodesmium spp., while aerosol addition predominantly enhanced the presence of heterotrophic diazotrophs including Pseudomonas and Desulfovibrio. Our results indicate that sources of nutrients supplied via Saharan dust and polluted aerosol pulses to the stratified surface Eastern Mediterranean waters could increase the contribution of diazotrophs and N2 fixation in these ultraoligotrophic waters and impact productivity and biogeochemical cycling.

  2. AATSR Single View Satellite Aerosol Retrievals Over the Persian Gulf During the 2004 United Arabic Emirates Unified Aerosol Experiment (UAE2)

    NASA Astrophysics Data System (ADS)

    Schoemaker, R. M.

    2006-12-01

    During the months of August and September 2004 the United Arabic Emirates Unified Aerosol Experiment (UAE2) mission took place in the marine and desert region of the United Arabic Emirates. One of the primary goals of the mission was to evaluate and improve scientific based satellite aerosol and ocean retrieval products. Important aspect was the calibration and validation of remote sensing systems in order to gain more insight in space-based retrievals over this part of the region. This paper contributes to part of the space-based mission objectives and governs the retrieval of atmospheric aerosol properties over water through data from the AATSR instrument on board the European ENVISAT satellite. At TNO Defence, Security and Safety the retrieval of aerosol properties from AATSR is performed by means of the dual view algorithm for application over land and the single view algorithm for application over ocean. Both algorithms have been merged into a fast and efficient algorithm that allows for near real-time processing and which is suitable for semi-operational use. Data from retrievals over water have been compared with ground-truth measurements from the AERONET sun photometers present for the three water sites in the Persian Gulf during the campaign. The properties retrieved are a) aerosol optical depth for the visible wavelengths of AATSR and b) the Ångström wavelength coefficient α as an indicator for the size distribution. Different aerosol types have been pre-modeled by means of AERONET phase function information, and saved as look-up tables for the retrieval procedure. By comparing the satellite retrieved information with the ground-truth data for each of the modeled aerosol type more insight in the retrieval procedure and in the aerosol make-up in this region is obtained.

  3. Raman lidar and sun photometer measurements of aerosols and water vapor during the ARM RCS experiment

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    The first Atmospheric Radiation Measurement (ARM) Remote Cloud Study (RCS) Intensive Operations Period (IOP) was held during April 1994 at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site near Lamont, Oklahoma. This experiment was conducted to evaluate and calibrate state-of-the-art, ground based remote sensing instruments and to use the data acquired by these instruments to validate retrieval algorithms developed under the ARM program. These activities are part of an overall plan to assess general circulation model (GCM) parameterization research. Since radiation processes are one of the key areas included in this parameterization research, measurements of water vapor and aerosols are required because of the important roles these atmospheric constituents play in radiative transfer. Two instruments were deployed during this IOP to measure water vapor and aerosols and study their relationship. The NASA/Goddard Space Flight Center (GSFC) Scanning Raman Lidar (SRL) acquired water vapor and aerosol profile data during 15 nights of operations. The lidar acquired vertical profiles as well as nearly horizontal profiles directed near an instrumented 60 meter tower. Aerosol optical thickness, phase function, size distribution, and integrated water vapor were derived from measurements with a multiband automatic sun and sky scanning radiometer deployed at this site.

  4. Direct containment heating and aerosol generation during high pressure melt ejection experiments

    SciTech Connect

    Tarvell, W.W.; Brockmann, J.E.; Washington, K.E.; Pilch, M.; Marx, K.D.

    1988-01-01

    Containment loading in the form of increased atmosphere pressure and temperature during a severe reactor accident can result from the expulsion of core debris from the reactor cavity. This increase in the pressure and temperature can be accompanied by an aerosol source term that may have enhanced compositions of the more volatile radionuclide. Large scale experiments have been conducted in the Surtsey facility at Sandia National Laboratories to study the energy exchange processes and the generation of aerosols. Test results are reported here and compared to analytical predictions made by an experiment analysis code and a containment response model. The experiments show that the energy exchange and aerosol generation processes are greatly affected by trapping of the debris on the surfaces of the test chamber. Good agreement is achieved between experimental data and model predictions by incorporating models for debris trapping on surfaces and the formation of the retained material into drops that fall through the chamber at late time. 23 refs., 11 figs., 4 tabs.

  5. Experiment to Characterize Aircraft Volatile Aerosol and Trace-Species Emissions (EXCAVATE)

    NASA Technical Reports Server (NTRS)

    Anderson, B. E.; Branham, H.-S.; Hudgins, C. H.; Plant, J. V.; Ballenthin, J. O.; Miller, T. M.; Viggiano, A. A.; Blake, D. R.; Boudries, H.; Canagaratna, M.

    2005-01-01

    The Experiment to Characterize Aircraft Volatile and Trace Species Emissions (EXCAVATE) was conducted at Langley Research Center (LaRC) in January 2002 and focused upon assaying the production of aerosols and aerosol precursors by a modern commercial aircraft, the Langley B757, during ground-based operation. Remaining uncertainty in the postcombustion fate of jet fuel sulfur contaminants, the need for data to test new theories of particle formation and growth within engine exhaust plumes, and the need for observations to develop air quality models for predicting pollution levels in airport terminal areas were the primary factors motivating the experiment. NASA's Atmospheric Effects of Aviation Project (AEAP) and the Ultra Effect Engine Technology (UEET) Program sponsored the experiment which had the specific objectives of determining ion densities; the fraction of fuel S converted from S(IV) to S(VI); the concentration and speciation of volatile aerosols and black carbon; and gas-phase concentrations of long-chain hydrocarbon and PAH species, all as functions of engine power, fuel composition, and plume age.

  6. Characterization of mineral dust aerosols during the Saharan Dust Experiment (SHADE)

    NASA Astrophysics Data System (ADS)

    Léon, J.-F.; Tanré, D.; Haywood, J.; Pelon, J.; Kaufman, Y. J.

    2003-04-01

    Aerosols are known to be important in determining the Earth’s radiative balance. Dust aerosols are particularly interesting since, in addition to their scattering and absorbing properties that affect the solar radiation, they also perturb the terrestrial radiation. In addition, recent studies have shown that a significant proportion of mineral dust in the atmosphere may be of anthropogenic origin and therefore they may have an important role in climate change by exerting a significant radiative forcing. The Saharan Dust Experiment was designed to better determine the parameters that are relevant for computing the direct radiative effect of mineral dust. Two aircraft combining in situ measurements and remote sensing instruments were coordinated with satellite overpasses during the experiment which was based in Cape Verde during the period September 20-28, 2000. These in-situ and remotely sensed data provide valuable information on the microphysical, optical properties and radiative effects of a very large mineral dust outbreak with aerosol optical thickness up to 1.5. A new approach based on a synergy between active (lidar) and passive (spaceborne radiometer) remote sensing has been used to investigate the vertical structure of the dust plume. The retrieved profiles of extinction compare well with in situ aircraft measurements. Profiles derived from lidar measurements on September 25 highlight the presence of the so-called Saharan Air Layer, located between 2.2 and 4.5 km. Another dust layer within the sub-Saharan transition layer over the marine boundary layer is also observed. In this second layer, the effective radius of particles is significantly smaller than in the aloft layer. The trajectory analyses and the Total Mapping Ozone Spectrometer Aerosol Index suggest that the aerosols present at 1500m originates from West Mauritania. The higher aerosol layer originates from southern Algeria which confirms the difference of altitude of the dust transport

  7. On the Stratospheric Aerosol and Gas Experiment III on the International Space Station

    NASA Technical Reports Server (NTRS)

    Hernandez, Gloria; Zawodny, Joseph M.; Cisewski, Michael S.; Thornton, Brooke M.; Panetta, Andrew D,; Roell, Marilee M.; Vernier, Jean-Paul

    2014-01-01

    The Stratospheric Aerosol and Gas Experiment III on International Space Station (SAGE3/ISS) is anticipated to be delivered to Cape Canaveral in the spring of 2015. This is the fourth generation, fifth instrument, of visible/near-IR solar occultation instruments operated by the National Aeronautics and Space Agency (NASA) to investigate the Earth's upper atmosphere. The instrument is a moderate resolution spectrometer covering wavelengths from 290 nm to 1550 nm. The nominal science products include vertical profiles of trace gases, such as ozone, nitrogen dioxide and water vapor, along with multi-wavelength aerosol extinction. The SAGE3/ISS validation program will be based upon internal consistency of the measurements, detailed analysis of the retrieval algorithm, and comparisons with independent correlative measurements. The Instrument Payload (IP), mission architecture, and major challenges are also discussed.

  8. The Landes experiment: Biosphere-atmosphere exchanges of ozone and aerosol particles above a pine forest

    SciTech Connect

    Lamaud, E.; Labatut, A.; Lopez, A.; Fontan, J.; Druilhet, A.; Brunet, Y.

    1994-08-20

    An experiment to measure the transfer of trace gases in the lower atmosphere was performed in the forested area of {open_quotes} Les Landes {close_quotes} in southwestern France. This region is one of the largest remaining forests in western Europe, and consists predominantly of resinous trees (maritime pines). This experiment involved emission measurements of chemically reactive species, measurement methodologies, mechanisms for flux and the influence of these emissions on boundary layer chemistry. This paper presents preliminary results on the dry deposition of ozone and aerosol particles in the boundary layer. 28 refs., 15 figs.

  9. Aerosols, clouds, and precipitation in the North Atlantic trades observed during the Barbados aerosol cloud experiment - Part 1: Distributions and variability

    NASA Astrophysics Data System (ADS)

    Jung, Eunsil; Albrecht, Bruce A.; Feingold, Graham; Jonsson, Haflidi H.; Chuang, Patrick; Donaher, Shaunna L.

    2016-07-01

    Shallow marine cumulus clouds are by far the most frequently observed cloud type over the Earth's oceans; but they are poorly understood and have not been investigated as extensively as stratocumulus clouds. This study describes and discusses the properties and variations of aerosol, cloud, and precipitation associated with shallow marine cumulus clouds observed in the North Atlantic trades during a field campaign (Barbados Aerosol Cloud Experiment- BACEX, March-April 2010), which took place off Barbados where African dust periodically affects the region. The principal observing platform was the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter (TO) research aircraft, which was equipped with standard meteorological instruments, a zenith pointing cloud radar and probes that measured aerosol, cloud, and precipitation characteristics.The temporal variation and vertical distribution of aerosols observed from the 15 flights, which included the most intense African dust event during all of 2010 in Barbados, showed a wide range of aerosol conditions. During dusty periods, aerosol concentrations increased substantially in the size range between 0.5 and 10 µm (diameter), particles that are large enough to be effective giant cloud condensation nuclei (CCN). The 10-day back trajectories showed three distinct air masses with distinct vertical structures associated with air masses originating in the Atlantic (typical maritime air mass with relatively low aerosol concentrations in the marine boundary layer), Africa (Saharan air layer), and mid-latitudes (continental pollution plumes). Despite the large differences in the total mass loading and the origin of the aerosols, the overall shapes of the aerosol particle size distributions were consistent, with the exception of the transition period.The TO was able to sample many clouds at various phases of growth. Maximum cloud depth observed was less than ˜ 3 km, while most clouds were less than 1 km

  10. Aerosol Radiative Effects: Expected Variations in Optical Depth Spectra and Climate Forcing, with Implications for Closure Experiment Strategies

    NASA Technical Reports Server (NTRS)

    Russell, Philip B.; Stowe, L. L.; Hobbs, P. V.; Podolske, James R. (Technical Monitor)

    1995-01-01

    We examine measurement strategies for reducing uncertainties in aerosol direct radiative forcing by focused experiments that combine surface, air, and space measurements. Particularly emphasized are closure experiments, which test the degree of agreement among different measurements and calculations of aerosol properties and radiative effects. By combining results from previous measurements of large-scale smokes, volcanic aerosols, and anthropogenic aerosols with models of aerosol evolution, we estimate the spatial and temporal variability in optical depth spectra to be expected in the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX, planned for summer 1996 off the Eastern U.S. seaboard). In particular, we examine the expected changes in the wavelength dependence of optical depth as particles evolve through nucleation, growth by condensation and coagulation, and removal via sedimentation. We then calculate the expected radiative climate forcing (i.e. change in net radiative flux) for typical expected aerosols and measurement conditions (e.g. solar elevations, surface albedos, radiometer altitudes). These calculations use new expressions for flux and albedo changes, which account not only for aerosol absorption, but also for instantaneous solar elevation angles and the dependence of surface albedo on solar elevation. These factors, which are usually ignored or averaged in calculations of global aerosol effects, can have a strong influence on fluxes measured in closure experiments, and hence must be accounted for in calculations if closure is to be convincingly tested. We compare the expected measurement signal to measurement uncertainties expected for various techniques in various conditions. Thereby we derive recommendations for measurement strategies that combine surface, airborne, and spaceborne measurements.

  11. Aerosol Physical and Chemical Properties Before and After the Manaus Plume in the GoAmazon2014 Experiment

    NASA Astrophysics Data System (ADS)

    Artaxo, P.; Barbosa, H. M.; Ferreira De Brito, J.; Wurm, F.; Holanda, B. A.; Carbone, S.; Arana, A.; Cirino, G. G.; Souza, R. A. F. D.; Rizzo, L. V.; Martin, S. T.; Andreae, M. O.; Holben, B. N.; Schafer, J.

    2014-12-01

    As part of the GoAmazon2014 experiment, several aerosol and trace gas monitoring stations are being operated for at least one year before and after the Manaus plume. Three sites are being operated in pristine conditions, with atmospheric properties under natural biogenic conditions. These three sites called T0 are: ATTO (Amazon Tall Tower Observatory), ZF2 ecological research site and a third site called EMBRAPA. After the air masses are exposed to the Manaus plume, one site (called T2) is being operated right on the opposite side of the Negro River under the direct influence of the Manaus plume at 5 Km downwind of Manaus. Finally, at about 150 Km downwind of Manaus is the T3 Manacapuru site. Aerosol chemical composition is being analyzed using filters for fine (PM2.5) and coarse mode aerosol as well as three Aerodyne ACSM (Aerosol Chemical Speciation Monitors) instruments. Aerosol absorption is being studied with several aethalometers and MAAP (Multi Angle Absorption Photometers). Aerosol light scattering are being measured at several wavelengths using nephelometers. Aerosol size distribution is determined using scanning mobility particle sizers. The aerosol column is measures using AERONET sunphotometers before and after the Manaus plume, as well as several Lidar systems. The three sites before the Manaus plume show remarkable similar variability in aerosol concentrations and optical properties. This pattern is very different at the T2 site, with large aerosol concentrations enhancing aerosol absorption and scattering significantly. The aerosol is very oxidized before being exposed to the Manaus plume, and this pattern changes significantly for T2 and T3 sites, with a much higher presence of less oxidized aerosol. Typical ozone concentrations at mid-day before Manaus plume is a low 10-12 ppb, value that changes to 50-70 ppb for air masses suffering the influence of Manaus plume. A detailed comparison of aerosol characteristics and composition for the several

  12. Overview of the Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station

    NASA Astrophysics Data System (ADS)

    Flittner, David; Pitts, Michael; Zawodny, Joe; Hill, Charles; Damadeo, Robert; Moore, Randy; Cisewski, Michael

    2012-07-01

    The Stratospheric Aerosol and Gas Experiment (SAGE) III is the fourth generation of solar occultation instruments operated by NASA, the first coming under a different acronym, to investigate the Earth's upper atmosphere. Three flight-ready SAGE III instruments were built by Ball Aerospace in the late 1990s, with one launched aboard the former Russian Avaiation and Space Agency (now known as Roskosmos) Meteor-3M (M3M) platform on 10 December 2001 (continuing until the platform lost power in 2006). Another of the original instruments was manifested for the International Space Station (ISS) in the 2004 time frame, but was delayed because of budgetary considerations. Fortunately, that SAGE III/ISS mission was restarted in 2009 with a major focus upon filling an anticipated gap in ozone and aerosol observations in the second half of this decade. This exciting mission utilizes contributions from both the Science Mission Directorate and the Human Exploration and Operations Mission Directorate within the National Aeronautics and Space Administration and the European Space Agency to enable scientific measurements that will provide the basis for the analysis of five of the nine critical constituents identified in the U.S. National Plan for Stratospheric Monitoring. A related paper by Anderson et al. discusses the. Presented here is an overview of the mission architecture, its implementation and the data that will be produced by SAGE III/ISS, including their expected accuracy and coverage. The 52-degree inclined orbit of the ISS is well-suited for solar occultation and provides near-global observations on a monthly basis with excellent coverage of low and mid-latitudes. This is similar to that of the SAGE II mission (1985-2005), whose data set has served the international atmospheric science community as a standard for stratospheric ozone and aerosol measurements. The nominal science products include vertical profiles of trace gases, such as ozone, nitrogen dioxide and water

  13. Comparison of In Situ Aerosol Data from the ACE-Asia 2001 Experiment

    NASA Astrophysics Data System (ADS)

    Knobelspiesse, K. D.; Pietras, C.; Miller, M. A.; Reynolds, R. M.; Frouin, R.; Quinn, P. K.; Deschamps, P. Y.; Werdell, P. J.; Fargion, G. S.

    2002-05-01

    The Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) is an international, multidisciplinary project to further knowledge about atmospheric aerosols. ACE-Asia included an intensive field measurement campaign during the spring of 2001 off the coasts of China, Japan and Korea. The Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project participated in the ACE-Asia cruise of the R/V Ronald H. Brown, which departed from Hawaii on 2001/03/15, sailed west to the Sea of Japan, and finished in Yokosuka, Japan on 2001/04/19. The SIMBIOS Project compares and merges data projects from multiple ocean color missions. As In Situ data are essential for merger and comparison of satellite ocean color measurements, the Project is interested in instrumentation devopment and data base building. The SeaWiFS Bio-optical Archive and Storage System (SeaBASS) is the database used and maintained by the SIMBIOS project. The ACE-Asia cruise was an excellent opportunity to compare data from a variety of maritime sun photometers, as several aerosol conditions were experienced. These included low Aerosol Optical Thickness (AOT) maritime conditions near Hawaii and extremely high AOT dust conditions in the Sea of Japan. Concurrant measurements were made with the PREDE POM-01 Mark II radiometer, a Laboratoire d'Optique Atmosphérique (LOA) SIMBAD, a Laboratorie d'Optique Atmosphérique (LOA) SIMBAD-a, two Solar Light, Inc. Microtops II's, and Brookhaven National Laboratory's Fast Rotating Shadowband Radiometer (FRSR). In addition, a Micro Pulse Lidar (MPL) was deployed that provides vertical aerosol distributions. Data were processed utilizing new algorithms to screen errors due to improper pointing at the sun, a problem previously recognized for the Microtops II. Comparisons of AOT at 500nm and Angstrom Exponent were made for all the instruments. The hand held, direct solar sun photometers (Microtops II, SIMBAD and SIMBADa

  14. Laboratory Experiments and Instrument Development for the Study of Atmospheric Aerosols

    SciTech Connect

    Davidovits, Paul

    2011-12-10

    -cost extension period) of our grant, we extended our studies to perform experiments on the controlled production and characterization of secondary organic aerosol.

  15. Stratospheric aerosol and gas experiments I and II comparisons with ozonesondes

    SciTech Connect

    Veiga, R.E.; Cunnold, D.M.; Chu, W.P.

    1995-05-20

    Ozone profiles measured by the Stratospheric Aerosol and Gas Experiments (SAGE) I and II are compared with ozonesonde profiles at 24 stations over the period extending from 1979 through 1991. Ozonesonde/satellite differences at 21 stations with SAGE II overpasses were computed down to 11.5 km in the midlatitudes, to 15.5 km in the lower latitudes, and for nine stations with SAGE I overpasses down to 15.5 km. The set of individual satellite and ozonesonde profile comparisons most closely colocated in time and space shows mean absolute differences relative to the satellite measurement of 6 {plus_minus} 2% for SAGE II and 8 {plus_minus}3% for SAGE I. The ensemble of ozonesonde/satellite differences, when averaged over all altitudes, shows that for SAGE II, 70% were less than 5%, whereas for SAGE I, 50% were less than 5%. The best agreement occurred in the altitude region near the ozone density maximum where almost all the relative differences were less than 5%. Most of the statistically significant differences occurred below the ozone maximum down to the tropopause in the region of steepest ozone gradients and typically ranged between 0 and {minus}20%. Correlations between ozone and aerosol extinction in the northern midlatitudes indicate that aerosols had no discernible impact on the ozonesonde/satellite differences and on the stratosphere during 1984 to mid-1991. 42 refs., 8 figs., 1 tab.

  16. Assessment of aerosol optical property and radiative effect for the layer decoupling cases over the northern South China Sea during the 7-SEAS/Dongsha Experiment

    NASA Astrophysics Data System (ADS)

    Pani, Shantanu Kumar; Wang, Sheng-Hsiang; Lin, Neng-Huei; Tsay, Si-Chee; Lolli, Simone; Chuang, Ming-Tung; Lee, Chung-Te; Chantara, Somporn; Yu, Jin-Yi

    2016-05-01

    The aerosol radiative effect can be modulated by the vertical distribution and optical properties of aerosols, particularly when aerosol layers are decoupled. Direct aerosol radiative effects over the northern South China Sea (SCS) were assessed by incorporating an observed data set of aerosol optical properties obtained from the Seven South East Asian Studies (7-SEAS)/Dongsha Experiment into a radiative transfer model. Aerosol optical properties for a two-layer structure of aerosol transport were estimated. In the radiative transfer calculations, aerosol variability (i.e., diversity of source region, aerosol type, and vertical distribution) for the complex aerosol environment was also carefully quantified. The column-integrated aerosol optical depth (AOD) at 500 nm was 0.1-0.3 for near-surface aerosols and increased 1-5 times in presence of upper layer biomass-burning aerosols. A case study showed the strong aerosol absorption (single-scattering albedo (ω) ≈ 0.92 at 440 nm wavelength) exhibited by the upper layer when associated with predominantly biomass-burning aerosols, and the ω (≈0.95) of near-surface aerosols was greater than that of the upper layer aerosols because of the presence of mixed type aerosols. The presence of upper level aerosol transport could enhance the radiative efficiency at the surface (i.e., cooling) and lower atmosphere (i.e., heating) by up to -13.7 and +9.6 W m-2 per AOD, respectively. Such enhancement could potentially modify atmospheric stability, can influence atmospheric circulation, as well as the hydrological cycle over the tropical and low-latitude marginal northern SCS.

  17. MELCOR 1.8.1 assessment: PNL Ice Condenser Aerosol Experiments

    SciTech Connect

    Gross, R.J.

    1993-06-01

    The MELCOR code was used to simulate PNL`s Ice Condenser Experiments 11-6 and 16-11. In these experiments, ZnS was injected into a mixing chamber, and the combined steam/air/aerosol mixture flowed into an ice condenser which was l4.7m tall. Experiment 11-6 was a low flow test; Experiment l6-1l was a high flow test. Temperatures in the ice condenser region and particle retention were measured in these tests. MELCOR predictions compared very well to the experimental data. The MELCOR calculations were also compared to CONTAIN code calculations for the same tests. A number of sensitivity studies were performed. It as found that simulation time step, aerosol parameters such as the number of MAEROS components and sections used and the particle density, and ice condenser parameters such as the energy capacity of the ice, ice heat transfer coefficient multiplier, and ice heat structure characteristic length all could affect the results. Thermal/hydraulic parameters such as control volume equilibrium assumptions, flow loss coefficients, and the bubble rise model were found to affect the results less significantly. MELCOR results were not machine dependent for this problem.

  18. Atmospheric Radiation Measurment (ARM) Data from the Ganges Valley, India for the Ganges Valley Aerosol Experiment (GVAX)

    DOE Data Explorer

    In 2011 and 2012, the Ganges Valley Aerosol Experiment (GVAX) began in the Ganges Valley region of India. The objective was to obtain measurements of clouds, precipitation, and complex aerosols to study their impact on cloud formation and monsoon activity in the region. During the Indian Ocean Experiment (INDOEX) field studies, aerosols from the Ganges Valley region were shown to affect cloud formation and monsoon activity over the Indian Ocean. The complex field study used the ARM Mobile Facility (AMF) to measure radiative, cloud, convection, and aerosol characteristics over the mainland. The resulting data set captured pre-monsoon to post-monsoon conditions to establish a comprehensive baseline for advancements in the study of the effects of atmospheric conditions of the Ganges Valley.

  19. Organic Aerosol Formation in the Humid, Photochemically-Active Southeastern US: SOAS Experiments and Simulations

    NASA Astrophysics Data System (ADS)

    Sareen, N.; Lim, Y. B.; Carlton, A. G.; Turpin, B. J.

    2013-12-01

    Aqueous multiphase chemistry in the atmosphere can lead to rapid transformation of organic compounds, forming highly oxidized low volatility organic aerosol and, in some cases, light absorbing (brown) carbon. Because liquid water is globally abundant, this chemistry could substantially impact climate, air quality, health, and the environment. Gas-phase precursors released from biogenic and anthropogenic sources are oxidized and fragmented forming water-soluble gases that can undergo reactions in the aqueous phase (in clouds, fogs, and wet aerosols) leading to the formation of secondary organic aerosol (SOAAQ). Recent studies have highlighted the role of certain precursors like glyoxal, methylglyoxal, glycolaldehyde, acetic acid, acetone, and epoxides in the formation of SOAAQ. The goal of this work is to identify other precursors that are atmospherically important. In this study, ambient mixtures of water-soluble gases were scrubbed from the atmosphere at Brent, Alabama during the Southern Oxidant and Aerosol Study (SOAS). Four mist chambers in parallel collected ambient gases in a DI water medium at 20-25 LPM with a 4 hr collection time. Total organic carbon (TOC) values in daily composited samples were 64-180 μM. Aqueous OH radical oxidation experiments were conducted with these mixtures in a newly designed cuvette chamber to understand the formation of SOA through gas followed by aqueous chemistry. OH radicals (3.5E-2 μM [OH] s-1) were formed in-situ in the chamber, continuously by H2O2 photolysis. Precursors and products of these aqueous OH experiments were characterized using ion chromatography (IC), electrospray ionization mass spectrometry (ESI-MS), and IC-ESI-MS. ESI-MS results from a June 12th, 2013 sample showed precursors to be primarily odd, positive mode ions, indicative of the presence of non-nitrogen containing alcohols, aldehydes, organic peroxides, or epoxides. Products were seen in the negative mode and included organic acid ions like pyruvate

  20. Aerosol and cloud chemistry of amines from CCS - reactivity experiments and numerical modeling

    NASA Astrophysics Data System (ADS)

    Weller, Christian; Tilgner, Andreas; Herrmann, Hartmut

    2013-04-01

    Capturing CO2 from the exhaust of power plants using amine scrubbing is a common technology. Therefore, amines can be released during the carbon capture process. To investigate the tropospheric chemical fate of amines from CO2 capturing processes and their oxidation products, the impact of aqueous aerosol particles and cloud droplets on the amine chemistry has been considered. Aqueous phase reactivity experiments of NO3 radicals and ozone with relevant amines and their corresponding nitrosamines were performed. Furthermore, nitrosamine formation and nitrosamine photolysis was investigated during laboratory experiments. These experiments implicated that aqueous phase photolysis can be an effective sink for nitrosamines and that ozone is unreactive towards amines and nitrosamines. Multiphase phase oxidation schemes of amines, nitrosamines and amides were developed, coupled to the existing multiphase chemistry mechanism CAPRAM and built into the Lagrangian parcel model SPACCIM using published and newly measured data. As a result, both deliquescent particles and cloud droplets are important compartments for the multiphase processing of amines and their products. Amines can be readily oxidised by OH radicals in the gas and cloud phase during daytime summer conditions. However, amine oxidation is restricted during winter conditions with low photochemical activity leading to long lifetimes of amines. The importance of the gas and aqueous phase depends strongly on the partitioning of the different amines. Furthermore, the simulations revealed that the aqueous formation of nitrosamines in aerosol particles and could droplets is not a relevant process under tropospheric conditions.

  1. SPEAM-II experiment for the measurement of stratospheric NO2, O3 and aerosols

    NASA Technical Reports Server (NTRS)

    Mcelroy, C. T.; Mcarthur, L. J. B.; Kerr, J. B.; Wardle, D. I.; Tarasick, D.; Midwinter, C.

    1994-01-01

    Following the success of the Sunphotometer Earth Atmosphere Measurement (SPEAM-I) experiment, a more involved experiment was developed to fly as part of the second set of Canadian Experiments (CANEX-2) which will fly on the US Space Shuttle in the fall of 1992. The instrument complement includes an IBM-PC compatible control computer, a hand-held diode array spectrophotometer, and an interference-filter, limb imaging radiometer for the measurement of the atmospheric airglow. The hand-held spectrometer will measure nitrogen dioxide, ozone and aerosols. The limb imaging radiometer will observe emissions from the O2(1 DELTA) and O2(1 SIGMA) airglow bands. Only the spectrophotometer will be discussed here.

  2. Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign

    NASA Astrophysics Data System (ADS)

    Mallet, M.; Dulac, F.; Formenti, P.; Nabat, P.; Sciare, J.; Roberts, G.; Pelon, J.; Ancellet, G.; Tanré, D.; Parol, F.; Denjean, C.; Brogniez, G.; di Sarra, A.; Alados-Arboledas, L.; Arndt, J.; Auriol, F.; Blarel, L.; Bourrianne, T.; Chazette, P.; Chevaillier, S.; Claeys, M.; D'Anna, B.; Derimian, Y.; Desboeufs, K.; Di Iorio, T.; Doussin, J.-F.; Durand, P.; Féron, A.; Freney, E.; Gaimoz, C.; Goloub, P.; Gómez-Amo, J. L.; Granados-Muñoz, M. J.; Grand, N.; Hamonou, E.; Jankowiak, I.; Jeannot, M.; Léon, J.-F.; Maillé, M.; Mailler, S.; Meloni, D.; Menut, L.; Momboisse, G.; Nicolas, J.; Podvin, T.; Pont, V.; Rea, G.; Renard, J.-B.; Roblou, L.; Schepanski, K.; Schwarzenboeck, A.; Sellegri, K.; Sicard, M.; Solmon, F.; Somot, S.; Torres, B.; Totems, J.; Triquet, S.; Verdier, N.; Verwaerde, C.; Waquet, F.; Wenger, J.; Zapf, P.

    2016-01-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx; http://charmex.lsce.ipsl.fr) is a collaborative research program federating international activities to investigate Mediterranean regional chemistry-climate interactions. A special observing period (SOP-1a) including intensive airborne measurements was performed in the framework of the Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region (ADRIMED) project during the Mediterranean dry season over the western and central Mediterranean basins, with a focus on aerosol-radiation measurements and their modeling. The SOP-1a took place from 11 June to 5 July 2013. Airborne measurements were made by both the ATR-42 and F-20 French research aircraft operated from Sardinia (Italy) and instrumented for in situ and remote-sensing measurements, respectively, and by sounding and drifting balloons, launched in Minorca. The experimental setup also involved several ground-based measurement sites on islands including two ground-based reference stations in Corsica and Lampedusa and secondary monitoring sites in Minorca and Sicily. Additional measurements including lidar profiling were also performed on alert during aircraft operations at EARLINET/ACTRIS stations at Granada and Barcelona in Spain, and in southern Italy. Remote-sensing aerosol products from satellites (MSG/SEVIRI, MODIS) and from the AERONET/PHOTONS network were also used. Dedicated meso-scale and regional modeling experiments were performed in relation to this observational effort. We provide here an overview of the different surface and aircraft observations deployed during the ChArMEx/ADRIMED period and of associated modeling studies together with an analysis of the synoptic conditions that determined the aerosol emission and transport. Meteorological conditions observed during this campaign (moderate temperatures and southern flows) were not favorable to producing high

  3. Analysis of shipboard aerosol optical thickness measurements from multiple sunphotometers aboard the R/V Ronald H. Brown during the Aerosol Characterization Experiment - Asia

    NASA Astrophysics Data System (ADS)

    Miller, Mark A.; Knobelspiesse, Kirk; Frouin, Robert; Bartholomew, Mary Jane; Reynolds, R. Michael; Pietras, Christophe; Fargion, Giulietta; Quinn, Patricia; Thieuleux, François

    2005-06-01

    Marine sunphotometer measurements collected aboard the R/V Ronald H. Brown during the Aerosol Characterization Experiment - Asia (ACE-Asia) are used to evaluate the ability of complementary instrumentation to obtain the best possible estimates of aerosol optical thickness and Ångstrom exponent from ships at sea. A wide range of aerosol conditions, including clean maritime conditions and highly polluted coastal environments, were encountered during the ACE-Asia cruise. The results of this study suggest that shipboard hand-held sunphotometers and fast-rotating shadow-band radiometers (FRSRs) yield similar measurements and uncertainties if proper measurement protocols are used and if the instruments are properly calibrated. The automated FRSR has significantly better temporal resolution (2 min) than the hand-held sunphotometers when standard measurement protocols are used, so it more faithfully represents the variability of the local aerosol structure in polluted regions. Conversely, results suggest that the hand-held sunphotometers may perform better in clean, maritime air masses for unknown reasons. Results also show that the statistical distribution of the Ångstrom exponent measurements is different when the distributions from hand-held sunphotometers are compared with those from the FRSR and that the differences may arise from a combination of factors.

  4. Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign

    NASA Astrophysics Data System (ADS)

    Mallet, M.; Dulac, F.; Formenti, P.; Nabat, P.; Sciare, J.; Roberts, G.; Pelon, J.; Ancellet, G.; Tanré, D.; Parol, F.; di Sarra, A.; Alados, L.; Arndt, J.; Auriol, F.; Blarel, L.; Bourrianne, T.; Brogniez, G.; Chazette, P.; Chevaillier, S.; Claeys, M.; D'Anna, B.; Denjean, C.; Derimian, Y.; Desboeufs, K.; Di Iorio, T.; Doussin, J.-F.; Durand, P.; Féron, A.; Freney, E.; Gaimoz, C.; Goloub, P.; Gómez-Amo, J. L.; Granados-Muñoz, M. J.; Grand, N.; Hamonou, E.; Jankowiak, I.; Jeannot, M.; Léon, J.-F.; Maillé, M.; Mailler, S.; Meloni, D.; Menut, L.; Momboisse, G.; Nicolas, J.; Podvin, J.; Pont, V.; Rea, G.; Renard, J.-B.; Roblou, L.; Schepanski, K.; Schwarzenboeck, A.; Sellegri, K.; Sicard, M.; Solmon, F.; Somot, S.; Torres, B.; Totems, J.; Triquet, S.; Verdier, N.; Verwaerde, C.; Wenger, J.; Zapf, P.

    2015-07-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx; http://charmex.lsce.ipsl.fr) is a collaborative research program federating international activities to investigate Mediterranean regional chemistry-climate interactions. A special observing period (SOP-1a) including intensive airborne measurements was performed in the framework of the Aerosol Direct Radiative Forcing on the Mediterranean Climate (ADRIMED) project during the Mediterranean dry season over the western and central Mediterranean basins, with a focus on aerosol-radiation measurements and their modeling. The SOP-1a took place from 11 June to 5 July 2013. Airborne measurements were made by both the ATR-42 and F-20 French research aircraft operated from Sardinia (Italy) and instrumented for in situ and remote-sensing measurements, respectively, and by sounding and drifting balloons, launched in Minorca. The experimental set-up also involved several ground-based measurement sites on islands including two ground-based reference stations in Corsica and Lampedusa and secondary monitoring sites in Minorca and Sicily. Additional measurements including lidar profiling were also performed on alert during aircraft operations at EARLINET/ACTRIS stations at Granada and Barcelona in Spain, and in southern Italy. Remote sensing aerosol products from satellites (MSG/SEVIRI, MODIS) and from the AERONET/PHOTONS network were also used. Dedicated meso-scale and regional modelling experiments were performed in relation to this observational effort. We provide here an overview of the different surface and aircraft observations deployed during the ChArMEx/ADRIMED period and of associated modeling studies together with an analysis of the synoptic conditions that determined the aerosol emission and transport. Meteorological conditions observed during this campaign (moderate temperatures and southern flows) were not favorable to produce high level of atmospheric pollutants nor

  5. The Cloud Aerosol Interactions and Precipitation Enhancement Experiment (CAIPEEX): overview and prominent results

    NASA Astrophysics Data System (ADS)

    Kulkarni, J. R.; Maheskumar, R. S.; Konwar, M.; Deshpande, C. G.; Morwal, S. B.; Padma Kumari, B.; Joshi, R. R.; Pandithurai, G.; Bhalwankar, R. V.; Mujumdar, V. R.; Goswami, B.; Rosenfeld, D.

    2009-12-01

    “Cloud-Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX)”, an Indian national program, funded by Ministry of Earth Sciences, (MoES), Govt. of India is being conducted by Indian Institute of Tropical Meteorology (IITM), Pune during the period 2009-2012. CAIPEEX has two phases. Phase I is devoted for intensive cloud and aerosol observations over different parts of India using an instrumented aircraft. Phase II is devoted for randomized precipitation enhancement experiment. The phase I is being carried out during the period May-September 2009. The main scientific objectives of Phase I are : To measure background concentrations of aerosols and cloud condensation nuclei (CCN) during pre-monsoon and monsoon seasons over different parts of the country. Measurements of the associated differences in convective cloud microstructure and precipitation forming processes. The important preliminary results from the observational studies are: 1) During the pre-monsoon thick layer of brown haze extends to height of about 5-6 km at the foothills of the Himalaya, but does not normally spill over into the Tibetan Plateau. 2) The deep clouds that form in this layer are typically triggered at the slopes of the Himalaya. The clouds are super-continental microphysically, which means that the cloud drops are very small and prevent any warm rain. However, much ice is formed quickly, probably due to the ice nucleating activity of the aerosols. 3) In the pre-monsoon phase over central and southern India the clouds have similar nature as described for the foothills of the Himalaya, but with lower bases. Still, warm rain is substantially suppressed. During the monsoon, the clouds in the Bangalore-Hyderabad rain shadow area lose quickly their ability to produce warm rain with the increasing levels of CCN eastward away from the west coast. 4) A major finding was the dominance of thick haze in the Arabian Sea during the SW monsoon. It appears to be mostly of Arabian and

  6. Comparison of Stratospheric Aerosol and Gas Experiment II and balloon-borne stratospheric water vapor measurements

    NASA Technical Reports Server (NTRS)

    Pruvost, P.; Ovarlez, J.; Lenoble, J.; Chu, W. P.

    1993-01-01

    The Stratospheric Aerosol and Gas Experiment II has one channel at 940 nm related to water vapor. Two inversion procedures were developed independently in order to obtain the water vapor profile: the Chahine method by the Langley Research Center, and the Mill method by the Laboratoire d'Optique Atmospherique. Comparisons were made between these two algorithms and some results are presented at midlatitudes (about 45 deg N) and tropical latitudes (12-25 deg S). They are compared with in situ frost point hygrometer data provided by balloon experiments from the Laboratoire de Meteorologie Dynamique. At +/- 0.5 ppmv, agreement between the inversion results and the experimental results was obtained in the altitude range from 18-19 to 26-27 km. Below 18-19 km and above 26-27 km the error is larger (sometimes 1 ppmv and more).

  7. Initial operation and checkout of stratospheric aerosol gas experiment and Meteor-3M satellite

    NASA Astrophysics Data System (ADS)

    Habib, Shahid; Makridenko, Leonid; Chu, William P.; Salikhov, Rashid; Moore, Alvah S., Jr.; Trepte, Charles R.; Cisewski, Michael S.

    2003-04-01

    Under a joint agreement between the National Aeronautics and Space Agency (NASA) and the Russian Aviation and Space Agency (RASA), the Stratospheric Aerosol Gas Experiment III (SAGE III) instrument was launched in low earth orbit on December 10, 2001 aboard the Russian Meteor-3M(1) satellite from the Baikonur Cosmodrome. SAGE III is a spectrometer that measures attenuated radiation in the 282 nm to 1550 nm wavelength range to obtain the vertical profiles of ozone, aerosols, and other chemical species that are critical in studying the trends for the global climate change phenomena. This instrument version is more advanced than any of the previous versions and has more spectral bands, elaborate data gathering and storage, and intelligent terrestrial software. There are a number of Russian scientific instruments aboard the Meteor satellite in addition to the SAGE III instrument. These instruments deal with land imaging and biomass changes, hydro-meteorological monitoring, and helio-geophysical research. This mission was under development for over a period of six years and offered a number of unique technical and program management challenges for both Agencies. SAGE III has a long space heritage, and four earlier versions of this instrument have flown in space for nearly two decades now. In fact, SAGE II, the fourth instrument, is still flying in space on NASA's Earth Radiation Budget Satellite (ERBS), and has been providing important atmospheric data over the last 18 years. It has provided vital ozone and aerosol data in the mid latitudes and has contributed vastly in ozone depletion research. Ball Aerospace built the instrument under Langley Research Center's (LaRC) management. This paper presents the process and approach deployed by the SAGE III and the Meteor teams in performing the initial on-orbit checkout. It further documents a number of early science results obtained by deploying low risk, carefully coordinated procedures in resolving the serious operational

  8. Inversion of solar extinction data from the Apollo-Soyuz Test Project Stratospheric Aerosol Measurement (ASTP/SAM) experiment

    NASA Technical Reports Server (NTRS)

    Pepin, T. J.

    1977-01-01

    The inversion methods are reported that have been used to determine the vertical profile of the extinction coefficient due to the stratospheric aerosols from data measured during the ASTP/SAM solar occultation experiment. Inversion methods include the onion skin peel technique and methods of solving the Fredholm equation for the problem subject to smoothing constraints. The latter of these approaches involves a double inversion scheme. Comparisons are made between the inverted results from the SAM experiment and near simultaneous measurements made by lidar and balloon born dustsonde. The results are used to demonstrate the assumptions required to perform the inversions for aerosols.

  9. Experience with Aerosol Generation During Rotary Mode Core Sampling in the Hanford Single Shell Waste Tanks

    SciTech Connect

    SCHOFIELD, J.S.

    2000-01-24

    This document provides data on aerosol concentrations in tank head spaces, total mass of aerosols in the tank head space and mass of aerosols sent to the exhauster during Rotary Mode Core Sampling from November 1994 through June 1999. A decontamination factor for the RMCS exhauster filter housing is calculated based on operation data.

  10. Linking variations in sea spray aerosol particle hygroscopicity to composition during two microcosm experiments

    NASA Astrophysics Data System (ADS)

    Forestieri, Sara D.; Cornwell, Gavin C.; Helgestad, Taylor M.; Moore, Kathryn A.; Lee, Christopher; Novak, Gordon A.; Sultana, Camille M.; Wang, Xiaofei; Bertram, Timothy H.; Prather, Kimberly A.; Cappa, Christopher D.

    2016-07-01

    The extent to which water uptake influences the light scattering ability of marine sea spray aerosol (SSA) particles depends critically on SSA chemical composition. The organic fraction of SSA can increase during phytoplankton blooms, decreasing the salt content and therefore the hygroscopicity of the particles. In this study, subsaturated hygroscopic growth factors at 85 % relative humidity (GF(85 %)) of predominately submicron SSA particles were quantified during two induced phytoplankton blooms in marine aerosol reference tanks (MARTs). One MART was illuminated with fluorescent lights and the other was illuminated with sunlight, referred to as the "indoor" and "outdoor" MARTs, respectively. Optically weighted GF(85 %) values for SSA particles were derived from measurements of light scattering and particle size distributions. The mean optically weighted SSA diameters were 530 and 570 nm for the indoor and outdoor MARTs, respectively. The GF(85 %) measurements were made concurrently with online particle composition measurements, including bulk composition (using an Aerodyne high-resolution aerosol mass spectrometer) and single particle (using an aerosol time-of-flight mass spectrometer) measurement, and a variety of water-composition measurements. During both microcosm experiments, the observed optically weighted GF(85 %) values were depressed substantially relative to pure inorganic sea salt by 5 to 15 %. There was also a time lag between GF(85 %) depression and the peak chlorophyll a (Chl a) concentrations by either 1 (indoor MART) or 3-to-6 (outdoor MART) days. The fraction of organic matter in the SSA particles generally increased after the Chl a peaked, also with a time lag, and ranged from about 0.25 to 0.5 by volume. The observed depression in the GF(85 %) values (relative to pure sea salt) is consistent with the large observed volume fractions of non-refractory organic matter (NR-OM) comprising the SSA. The GF(85 %) values exhibited a reasonable negative

  11. CalWater 2 - Precipitation, Aerosols, and Pacific Atmospheric Rivers Experiment

    NASA Astrophysics Data System (ADS)

    Spackman, Ryan; Ralph, Marty; Prather, Kim; Cayan, Dan; DeMott, Paul; Dettinger, Mike; Fairall, Chris; Leung, Ruby; Rosenfeld, Daniel; Rutledge, Steven; Waliser, Duane; White, Allen

    2014-05-01

    Emerging research has identified two phenomena that play key roles in the variability of the water supply and the incidence of extreme precipitation events along the West Coast of the United States. These phenomena include the role of (1) atmospheric rivers (ARs) in delivering much of the precipitation associated with major storms along the U.S. West Coast, and (2) aerosols—from local sources as well as those transported from remote continents—and their modulating effects on western U.S. precipitation. A better understanding of these processes is needed to reduce uncertainties in weather predictions and climate projections of extreme precipitation and its effects, including the provision of beneficial water supply. This presentation summarizes science gaps associated with (1) the evolution and structure of ARs including cloud and precipitation processes and air-sea interaction, and (2) aerosol interaction with ARs and the impact on precipitation, including locally-generated aerosol effects on orographic precipitation along the U.S. West Coast. Observations are proposed for multiple winter seasons as part of a 5-year broad interagency vision referred to as CalWater 2 to address these science gaps (http://esrl.noaa.gov/psd/calwater). In the near term, a science investigation is being planned including a targeted set of aircraft and ship-based measurements and associated evaluation of data in near-shore regions of California and in the eastern Pacific for an intensive observing period between January 2015 and March 2015. DOE's Atmospheric Radiation Measurement (ARM) program and NOAA are coordinating on deployment of airborne and ship-borne facilities for this period in a DOE-sponsored study called ACAPEX (ARM Cloud Aerosol and Precipitation Experiment) to complement CalWater 2. The motivation for this major study is based on findings that have emerged in the last few years from airborne and ground-based studies including CalWater and NOAA's HydroMeterology Testbed

  12. Lidar Observations of Tropospheric Aerosols Over Northeastern South Africa During the ARREX and SAFARI-2000 Dry Season Experiments

    NASA Technical Reports Server (NTRS)

    Campbell, James R.; Welton, Ellsworth J.; Spinhirne, James D.; Ji, Qiang; Tsay, Si-Chee; Piketh, Stuart J.; Barenbrug, Marguerite; Holben, Brent; Starr, David OC. (Technical Monitor)

    2002-01-01

    During the ARREX-1999 and SAFARI-2000 Dry Season experiments a micropulse lidar (523 nm) instrument was operated at the Skukuza Airport in northeastern South Africa. The Mar was collocated with a diverse array of passive radiometric equipment. For SAFARI-2000 the processed Mar data yields a daytime time-series of layer mean/derived aerosol optical properties, including extinction-to-backscatter ratios and vertical extinction cross-section profile. Combined with 523 run aerosol optical depth and spectral Angstrom exponent calculations from available CIMEL sun-photometer data and normalized broadband flux measurements the temporal evolution of the near surface aerosol layer optical properties is analyzed for climatological trends. For the densest smoke/haze events the extinction-to-backscatter ratio is found to be between 60-80/sr, and corresponding Angstrom exponent calculations near and above 1.75. The optical characteristics of an evolving smoke event from SAFARI-2000 are extensively detailed. The advecting smoke was embedded within two distinct stratified thermodynamic layers, causing the particulate mass to advect over the instrument array in an incoherent manner on the afternoon of its occurrence. Surface broadband flux forcing due to the smoke is calculated, as is the evolution in the vertical aerosol extinction profile as measured by the Han Finally, observations of persistent elevated aerosol during ARREX-1999 are presented and discussed. The lack of corroborating observations the following year makes these observation; both unique and noteworthy in the scope of regional aerosol transport over southern Africa.

  13. The VOCALS Regional Experiment: Aerosol-Cloud-Precipitation Interactions in Marine Boundary Layer Cloud

    NASA Astrophysics Data System (ADS)

    Wood, R.

    2012-12-01

    Robert Wood, C.S. Bretherton, C. R. Mechoso, R. A. Weller, B. J. Huebert, H. Coe, B. A. Albrecht, P. H. Daum, D. Leon, A. Clarke, P. Zuidema, C. W. Fairall, G. Allen, S. deSzoeke, G. Feingold, J. Kazil, S. Yuter, R. George, A. Berner, C. Terai, G. Painter, H. Wang, M. Wyant, D. Mechem The VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) is an international field program designed to make observations of poorly understood but critical components of the coupled climate system of the southeast Pacific (SEP), a region dominated by strong coastal upwelling, extensive cold SSTs, and home to the largest subtropical stratocumulus deck on Earth. VOCALS-REx took place during October and November 2008 and involved five research aircraft, two ships and two surface sites in northen Chile. A central theme of VOCALS-REx is the improved understanding of links between aerosols, clouds and precipitation and their impacts on marine stratocumulus radiative properties. In this presentation, we will present a synthesis of results from VOCALS-REx focusing on the following questions: (a) how are aerosols, clouds and precipitation inter-related in the SEP region? (b) what microphysical-macrophysical interactions are necessary for the formation and maintenance of open cells? (c) how do cloud and MBL properties change across the strong microphysical gradients from the South American coast to the remote ocean?

  14. Algorithms and sensitivity analyses for stratospheric aerosol and gas experiment II water vapor retrieval

    SciTech Connect

    Chu, W.P.; Thomason, L.W.; Buglia, J.J.; McCormick, M.P.; McMaster, L.M. ); Chiou, E.W.; Larsen, J.C. ); Rind, D. ); Oltmans, S. )

    1993-03-20

    This paper provides a detailed description of the current operational inversion algorithm for the retrieval of water vapor vertical profiles from the Stratospheric Aerosol and Gas Experiment II (SAGE II) occultation data at the 0.94-[mu]m wavelength channel. This algorithm is different from the algorithm used for the retrieval of the other species such as aerosol, ozone, and nitrogen dioxide because of the nonlinear relationship between the concentration versus the broad band absorption characteristics of water vapor. Included in the discussion of the retrieval algorithm are problems related to the accuracy of the computational scheme, accuracy of the removal of other interfering species, and the expected uncertainty of the retrieved profile. A comparative analysis on the computational schemes used for the calculation of the water vapor transmission at the 0.94-[mu]m wavelength region is presented. Analyses are also presented on the sensitivity of the retrievals to interferences from the other species which contribute to the total signature as observed at the 0.94-[mu]m wavelength channel on SAGE II instrument. Error analyses of the SAGE II water vapor retrieval is shown, indicating that good quality water vapor data are being produced by the SAGE II measurements. 27 refs., 10 figs., 1 tab.

  15. Transport of Aerosols from Asia and Their Radiative Effects Over the Western Pacific: A 3-D Model Study for ACE-Asia Experiment During Spring 2001

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Ginoux, Paul; Flatau, Piotr; Anderson, Tad; Masonis, Sarah; Russell, Phil; Schmid, Beat; Livingston, John; Redemann, Jens; Kahn, Ralph; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    The Aerosol Characterization Experiment-Asia (ACE-Asia) took place in Spring 2001 in the East Asia-West Pacific Ocean. During the ACE-Asia intensive field operation period, high concentrations of dust and anthropogenic aerosols were observed over the Yellow Sea and the Sea of Japan, which were transported out from the Asian continent, with the plume often extending to 6-8 km altitude. The multi-component aerosols originated from Asia are expected to exert a significant radiative forcing over the Pacific region. We present here results from the Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model of aerosol transport and radiative forcing in the context of ACE-Asia. The model calculated aerosol concentrations, extinctions, optical thickness, size distributions, and vertical profiles are compared with the aircraft and ship measurements, and the distributions of aerosols are compared with satellite data. The model will be used to understand the origins of the aerosols observed in ACE-Asia, estimate the contributions from anthropogenic and natural aerosols to the total aerosol optical thickness, investigate the effects of humidification and clouds on aerosol properties, and assess the radiative forcing of Asian aerosols over the Pacific region and in the northern hemisphere.

  16. Aerosol ultraviolet absorption experiment (2002 to 2004), part 2: absorption optical thickness, refractive index, and single scattering albedo

    NASA Astrophysics Data System (ADS)

    Krotkov, Nickolay A.; Bhartia, Pawan K.; Herman, Jay R.; Slusser, James R.; Scott, Gwendolyn R.; Labow, Gordon J.; Vasilkov, Alexander P.; Eck, Tom; Doubovik, Oleg; Holben, Brent N.

    2005-04-01

    Compared to the visible spectral region, very little is known about aerosol absorption in the UV. Without such information it is impossible to quantify the causes of the observed discrepancy between modeled and measured UV irradiances and photolysis rates. We report results of a 17-month aerosol column absorption monitoring experiment conducted in Greenbelt, Maryland, where the imaginary part of effective refractive index k was inferred from the measurements of direct and diffuse atmospheric transmittances by a UV-multifilter rotating shadowband radiometer [UV-MFRSR, U.S. Department of Agriculture (USDA) UV-B Monitoring and Research Network]. Colocated ancillary measurements of aerosol effective particle size distribution and refractive index in the visible wavelengths [by CIMEL sun-sky radiometers, National Aeronautics and Space Administration (NASA) Aerosol Robotic Network (AERONET)], column ozone, surface pressure, and albedo constrain the forward radiative transfer model input, so that a unique solution for k is obtained independently in each UV-MFRSR spectral channel. Inferred values of k are systematically larger in the UV than in the visible wavelengths. The inferred k values enable calculation of the single scattering albedo ω, which is compared with AERONET inversions in the visible wavelengths. On cloud-free days with high aerosol loadings [τext(440)>0.4], ω is systematically lower at 368 nm (<ω368>=0.94) than at 440 nm (<ω440>=0.96), however, the mean ω differences (0.02) are within expected uncertainties of ω retrievals (~0.03). The inferred ω is even lower at shorter UV wavelengths (<ω325>~<ω332>=0.92), which might suggest the presence of selectively UV absorbing aerosols. We also find that decreases with decrease in aerosol loading. This could be due to real changes in the average aerosol composition between summer and winter months at the Goddard Space Flight Center (GSFC) site.

  17. Preface to special section on East Asian Studies of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE)

    NASA Astrophysics Data System (ADS)

    Li, Zhanqing; Chen, H.; Cribb, M.; Dickerson, R.; Holben, B.; Li, C.; Lu, D.; Luo, Y.; Maring, H.; Shi, G.; Tsay, S.-C.; Wang, P.; Wang, Y.; Xia, X.; Zheng, Y.; Yuan, T.; Zhao, F.

    2007-11-01

    Papers published in this special section report findings from the East Asian Study of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE). They are concerned with (1) the temporal and spatial distributions of aerosol loading and precursor gases, (2) aerosol single scattering albedo (SSA), (3) aerosol direct radiative effects, (4) validation of satellite products, (5) transport mechanisms, and (6) the effects of air pollution on ecosystems. Aerosol loading is heaviest in mideastern China with a mean aerosol optical depth (AOD) of 0.5 and increasing to 0.7 around major cities that reduced daily mean surface solar radiation by ˜30-40 W m-2, but barely changed solar reflection at the top of the atmosphere. Aerosol loading, particle size and composition vary considerably with location and season. The MODIS AOD data from Collection 5 (C5) agree much better with ground data than earlier releases, but considerable discrepancies still exist because of treatments of aerosol SSA and surface albedo. Four methods are proposed/adopted to derive the SSA by means of remote sensing and in situ observation, which varies drastically with time and space. The nationwide means of AOD, Ångström exponent, and SSA (0.5 μm) in China are 0.69 ± 0.17, 1.06 ± 0.26, and 0.89 ± 0.04, respectively. Measurements of trace gases reveal substantial uncertainties in emission inventories. An analysis of aircraft measurements revealed that dry convection is an important mechanism uplifting pollutants over northern China. Model simulations of nitrogen deposition and impact of ozone pollution on net primary productivity indicate an increasing threat of air pollution on the ecosystem.

  18. Microanalysis of the aerosol collected over south-central New Mexico during the alive field experiment, May-December 1989

    NASA Astrophysics Data System (ADS)

    Sheridan, Patrick J.; Schnell, Russel C.; Kahl, Jonathan D.; Boatman, Joe F.; Garvey, Dennis M.

    Thirty-eight size-segregated aerosol samples were collected in the lower troposphere over the high desert of south-central New Mexico, using cascade impactors mounted onboard two research aircraft. Four of these samples were collected in early May, sixteen in mid-July, and the remaining ones in December 1989, during three segments of the ALIVE field initiative. Analytical electron microscope analyses of aerosol deposits and individual particles from these samples were performed to physically and chemically characterize the major particulate species present in the aerosol. Air-mass trajectories arriving at the sampling area in the May program were quite different from those calculated for the July period. In general, the May trajectories showed strong westerly winds, while the July winds were weaker and southerly, consistently passing over or very near the border cities of El Paso, Texas, and Ciudad Juarez, Mexico. Aerosol samples collected during the May period were predominantly fine (0.1-0.5 μm dia.), liquid H 2SO 4 droplets. Samples from the July experiment were comprised mostly of fine, solid (NH 4) 2SO 4 or mostly neutralized sulfate particles. In both sampling periods, numerous other particle classes were observed, including many types with probable terrestrial or anthropogenic sources. The numbers of these particles, however, were small when compared with the sulfates. Composite particle types, including sulfate/crustal and sulfate/carbonaceous, were also found to be present. The major differences in aerosol composition between the May and July samples (i.e. the extensive neutralization of sulfates in the July samples) can be explained by considering the different aerosol transport pathways and the proximity of the July aerosol to the El Paso/Juarez urban plume. Winds during the December experiment were quite variable, and may have contributed to the widely varying aerosol compositions observed in these samples. When the aircraft sampled the El Paso

  19. Micropulse lidar observations of tropospheric aerosols over northeastern South Africa during the ARREX and SAFARI 2000 dry season experiments

    NASA Astrophysics Data System (ADS)

    Campbell, James R.; Welton, Ellsworth J.; Spinhirne, James D.; Ji, Qiang; Tsay, Si-Chee; Piketh, Stuart J.; Barenbrug, Marguerite; Holben, Brent N.

    2003-07-01

    During the Aerosol Recirculation and Rainfall Experiment (ARREX 1999) and Southern African Regional Science Initiative (SAFARI 2000) dry season experiments, a micropulse lidar (523 nm) instrument was operated at the Skukuza Airport in northeastern South Africa. The lidar was colocated with a diverse array of passive radiometric equipment. For SAFARI 2000, a daytime time series of layer mean aerosol optical properties, including layer mean extinction-to-backscatter ratios and vertical extinction cross-section profiles are derived from the synthesis of the lidar data and aerosol optical depths from available AERONET Sun photometer data. Combined with derived spectral Angstrom exponents, normalized broadband flux measurements, and calculated air mass back-trajectories, the temporal evolution of the surface aerosol layer optical properties is analyzed for climatological trends. For dense biomass smoke events the extinction-to-backscatter ratio is between 50 and 90 sr, and corresponding spectral Angstrom exponent values are between 1.50 and 2.00. Observations of an advecting smoke event during SAFARI 2000 are shown. The smoke was embedded within two distinct stratified thermodynamic layers causing the particulate mass to advect over the instrument array in an incoherent manner on the afternoon of 1 September 2000. Significant surface broadband flux forcing of over -50 W/m2 was measured in this event. The evolution of the vertical aerosol extinction profile is profiled using the lidar data. Finally, observations of persistent elevated aerosol layers during ARREX 1999 are presented and discussed. Back-trajectory analyses combined with lidar and Sun photometer measurements indicate the likelihood for these aerosols being the result of long-range particulate transport from the southern and central South America.

  20. Inference of the aerosol Angstrom coefficient from SAGE short-wavelength data. [Stratospheric Aerosol and Gas Experiment

    NASA Technical Reports Server (NTRS)

    Lenoble, J.; Pruvost, P.

    1983-01-01

    SAGE four-channel transmission profiles are inverted to retrieve the extinction profiles from which the aerosol Angstrom coefficient alpha is obtained. The procedure allows one to check the influence of the NO2 absorption profile, which is small below 25 km. The results compare well with those obtained by a completely different procedure at NASA Langley Research Center, and the main features of the alpha profiles seem to be significant, even considering the rather large error bars. The relation between the retrieved Angstrom coefficient, the particle effective radius and the asymmetry factor is considered.

  1. A model for the natural and anthropogenic aerosols over the tropical Indian Ocean derived from Indian Ocean Experiment data

    NASA Astrophysics Data System (ADS)

    Satheesh, S. K.; Ramanathan, V.; Li-Jones, Xu; Lobert, J. M.; Podgorny, I. A.; Prospero, J. M.; Holben, B. N.; Loeb, N. G.

    1999-11-01

    The physical, chemical and radiative properties of aerosols are investigated over the tropical Indian Ocean during the first field phase (FFP) of the international Indian Ocean Experiment. The FFP was conducted during February 20 to March 31, 1998. The results shown here are from the Kaashidhoo Climate Observatory (KCO), a new surface observatory established on the tiny island of Kaashidhoo (4.965°N, 73.466°E) in the Republic of Maldives. From simultaneous measurements of aerosol physical, chemical, and radiative properties and the vertical structure from lidar, we have developed an aerosol model which, in conjunction with a Monte Carlo radiative transfer model, successfully explains (within a few percent) the observed solar radiative fluxes at the surface and at the top of the atmosphere. This agreement demonstrates the fundamental importance of measuring aerosol physical and chemical properties for modeling radiative fluxes. KCO, during the northeast monsoon period considered here, is downwind of the Indian subcontinent and undergoes variations in the aerosol visible optical depth τν from ˜0.1 to 0.4, with a monthly mean of ˜0.2. Lidar data suggest that the aerosol is confined largely to the first 3 kms. Sulfate and ammonium contribute ˜29% to τν; sea-salt and nitrate contributes ˜17%; mineral dust contributes ˜15%; and the inferred soot, organics, and fly ash contribute 11%, 20%, and 8% respectively. We estimate that anthropogenic sources may contribute as much as 65% to the observed τν. We consider both an externally and an internally mixed aerosol model with very little difference between the two in the computed radiative forcing. The observed scattering coefficients are in the upper range of those reported for other oceanic regions, the single-scattering albedos are as low as 0.9, and the Angstrom wavelength exponents of ˜1.2 indicate the abundance of submicron aerosols. In summary, the data and the model confirm the large impact of

  2. Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign

    NASA Astrophysics Data System (ADS)

    Mallet, M.; Dulac, F.; Formenti, P.; Nabat, P.; Sciare, J.; Roberts, G.; Pelon, J.; Ancellet, G.; Tanré, D.; Parol, F.; Denjean, C.; Brogniez, G.; di Sarra, A.; Alados-Arboledas, L.; Arndt, J.; Auriol, F.; Blarel, L.; Bourrianne, T.; Chazette, P.; Chevaillier, S.; Claeys, M.; D'Anna, B.; Derimian, Y.; Desboeufs, K.; Di Iorio, T.; Doussin, J.-F.; Durand, P.; Féron, A.; Freney, E.; Gaimoz, C.; Goloub, P.; Gómez-Amo, J. L.; Granados-Muñoz, M. J.; Grand, N.; Hamonou, E.; Jankowiak, I.; Jeannot, M.; Léon, J.-F.; Maillé, M.; Mailler, S.; Meloni, D.; Menut, L.; Momboisse, G.; Nicolas, J.; Podvin, T.; Pont, V.; Rea, G.; Renard, J.-B.; Roblou, L.; Schepanski, K.; Schwarzenboeck, A.; Sellegri, K.; Sicard, M.; Solmon, F.; Somot, S.; Torres, B.; Totems, J.; Triquet, S.; Verdier, N.; Verwaerde, C.; Waquet, F.; Wenger, J.; Zapf, P.

    2016-01-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx; http://charmex.lsce.ipsl.fr) is a collaborative research program federating international activities to investigate Mediterranean regional chemistry-climate interactions. A special observing period (SOP-1a) including intensive airborne measurements was performed in the framework of the Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region (ADRIMED) project during the Mediterranean dry season over the western and central Mediterranean basins, with a focus on aerosol-radiation measurements and their modeling. The SOP-1a took place from 11 June to 5 July 2013. Airborne measurements were made by both the ATR-42 and F-20 French research aircraft operated from Sardinia (Italy) and instrumented for in situ and remote-sensing measurements, respectively, and by sounding and drifting balloons, launched in Minorca. The experimental setup also involved several ground-based measurement sites on islands including two ground-based reference stations in Corsica and Lampedusa and secondary monitoring sites in Minorca and Sicily. Additional measurements including lidar profiling were also performed on alert during aircraft operations at EARLINET/ACTRIS stations at Granada and Barcelona in Spain, and in southern Italy. Remote-sensing aerosol products from satellites (MSG/SEVIRI, MODIS) and from the AERONET/PHOTONS network were also used. Dedicated meso-scale and regional modeling experiments were performed in relation to this observational effort. We provide here an overview of the different surface and aircraft observations deployed during the ChArMEx/ADRIMED period and of associated modeling studies together with an analysis of the synoptic conditions that determined the aerosol emission and transport. Meteorological conditions observed during this campaign (moderate temperatures and southern flows) were not favorable to producing high

  3. SAGE ground truth plan: Correlative measurements for the Stratospheric Aerosol and Gas Experiment (SAGE) on the AEM-B satellite

    NASA Technical Reports Server (NTRS)

    Russell, P. B. (Editor); Cunnold, D. M.; Grams, G. W.; Laver, J.; Mccormick, M. P.; Mcmaster, L. R.; Murcray, D. G.; Pepin, T. J.; Perry, T. W.; Planet, W. G.

    1979-01-01

    The ground truth plan is outlined for correlative measurements to validate the Stratospheric Aerosol and Gas Experiment (SAGE) sensor data. SAGE will fly aboard the Applications Explorer Mission-B satellite scheduled for launch in early 1979 and measure stratospheric vertical profiles of aerosol, ozone, nitrogen dioxide, and molecular extinction between 79 N and 79 S. latitude. The plan gives details of the location and times for the simultaneous satellite/correlative measurements for the nominal launch time, the rationale and choice of the correlative sensors, their characteristics and expected accuracies, and the conversion of their data to extinction profiles. In addition, an overview of the SAGE expected instrument performance and data inversion results are presented. Various atmospheric models representative of stratospheric aerosols and ozone are used in the SAGE and correlative sensor analyses.

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

    NASA Technical Reports Server (NTRS)

    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.

  5. Retrieval of composition and size distribution of stratospheric aerosols with the SAGE II satellite experiment

    NASA Technical Reports Server (NTRS)

    Yue, Glenn K.; Mccormick, M. P.; Chu, W. P.

    1986-01-01

    The SAGE II satellite system was launched on October 5, 1984. It has seven radiometric channels and is beginning to provide water vapor, NO2, and O3 concentration profiles and aerosol extinction profiles at a minimum of three wavelengths. A simple, fast and operational method of retrieving characteristics of stratospheric aerosols from the water vapor and three-wavelength aerosol extinction profiles is proposed. Some examples are given to show the practicality of the scheme. Possible sources of error for the retrieved values and the limitation of the proposed method are discussed. This method may also prove applicable to the study of aerosol characteristics in other multispectral extinction measurements.

  6. Developments and plans for new drifting balloon experiments in the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) project

    NASA Astrophysics Data System (ADS)

    Dulac, François; Durand, Pierre; Verdier, Nicolas; Renard, Jean-Baptiste; Mallet, Marc; Thouret, Valérie; Attié, Jean-Luc

    ChArMEx (the Chemistry-Aerosol Mediterranean Experiment; http://charmex.lsce.ipsl.fr) is a new integrated project which aims at an assessment of the present state of the atmospheric environment in the Mediterranean basin, of its impacts on air quality, regional climate and marine biogeochemistry, and of their evolution in a regional context of intense climate change and increasing anthropogenic pressure. The Mediterranean is indeed characterized by a long dry and sunny season with high concentrations of aerosols and gaseous pollutants such as ozone. ChArMEx plans large international coordinated field campaigns with surface stations and airborne platforms including drifting balloons for studying the ageing of continental air masses transported over the basin. We are willing to deploy two types of balloons: (i) The Aeroclipper is a low altitude streamlined balloon drifting at 50 m over the sea surface and equipped with a cable and a guide-rope in contact with the surface ocean. It moves on a quasi-Lagrangian trajectory depending on the surface wind and marine current. Its instru-mentation is distributed on one atmospheric gondola and one oceanic gondola with the aim to measure surface physical parameters (air and sea surface temperatures, wind, pressure and humidity) in order to derive turbulent fluxes of moisture, heat and momentum. (ii) The BPCL is a long duration super-pressure balloon designed to drift in the atmospheric boundary layer. It moves on a quasi-Lagrangian trajectory at an adjustable constant atmo-spheric density level which altitude ranges between a few hundreds of m and about 3 km. Its instrumentation includes air pressure, temperature and humidity. Both balloon types are equipped with a positioning system and a data transmission system. In addition we are developing new small instruments to be integrated in the payload of these two balloon types. This includes radiation sensors to measure visible and infrared fluxes, an optical particle counter

  7. The FLAME Deluge: organic aerosol emission ratios from combustion chamber experiments

    NASA Astrophysics Data System (ADS)

    Jolleys, Matthew; Coe, Hugh; McFiggans, Gordon; McMeeking, Gavin; Lee, Taehyoung; Sullivan, Amy; Kreidenweis, Sonia; Collett, Jeff

    2014-05-01

    A high level of variability has been identified amongst organic aerosol (OA) emission ratios (ER) from biomass burning (BB) under ambient conditions. However, it is difficult to assess the influences of potential drivers for this variability, given the wide range of conditions associated with wildfire measurements. Chamber experiments performed under controlled conditions provide a means of examining the effects of different fuel types and combustion conditions on OA emissions from biomass fuels. ERs have been characterised for 67 burns during the second Fire Laboratory at Missoula Experiment (FLAME II), involving 19 different species from 6 fuel types widely consumed in BB events in the US each year. Average normalised dOA/dCO ratios show a high degree of variability, both between and within different fuel types and species, typically exceeding variability between separate plumes in ambient measurements. Relationships with source conditions were found to be complex, with little consistent influence from fuel properties and combustion conditions for the entire range of experiments. No strong correlation across all fires was observed between dOA/dCO and modified combustion efficiency (MCE), which is used as an indicator of the proportional contributions of flaming and smouldering combustion phases throughout each burn. However, a negative correlation exists between dOA/dCO and MCE for some coniferous species, most notably Douglas fir, for which there is also an apparent influence from fuel moisture content. Significant contrasts were also identified between combustion emissions from different fuel components of additional coniferous species. Changes in fire efficiency were also shown to dramatically alter emissions for fires with very similar initial conditions. Although the relationship with MCE is variable between species, there is greater consistency with the level of oxygenation in OA. The ratio of the m/z 44 fragment to total OA mass concentration (f44) as

  8. Tropospheric water vapor and aerosol measurements obtained during LASE validation experiment

    SciTech Connect

    Browell, E.V.; Ismail, S.; Hall, W.M.; Moore, A.S.

    1996-10-01

    The Lidar Atmospheric Sensing Experiment (LASE) is a Differential Absorption Lidar (DIAL) system flown on the NASA ER-2 aircraft to remotely measure distributions of tropospheric water vapor, aerosols, and clouds. LASE was developed at the NASA Langley Research Center (LaRC) to demonstrate autonomous operation of a DIAL system from a high-altitude aircraft as an important step towards developing a spaceborne DIAL system. LASE uses a double pulsed Ti:sapphire laser operating in the 815-nm absorption band of water vapor to generate the on- and off-line DIAL laser pulses. The system has two avalanche photodiode detectors and three signal digitizers to preserve the lidar backscatter signals over a large dynamic range. In September 1995, LASE completed a comprehensive validation program at the NASA Wallops Flight Facility. The system was flown on the ER-2 during ten flights for a total of 60 hours. LASE measurements of tropospheric water vapor were compared with other remote and in situ measurements of water vapor from the ground and from aircraft which underflew the ER-2. Besides making intercomparisons with a number of water vapor sensors, this experiment incorporated a number of case studies related to atmospheric events including flights over and around Hurricane Luis over the Atlantic ocean, sea breeze development along the east coast of Virginia, and stratosphere-troposphere exchange. This paper presents data taken during this field experiment that demonstrate the accuracy of LASE for tropospheric water vapor measurements. The paper also discusses results from several of the atmospheric case studies conducted during this experiment and the potential future uses of LASE.

  9. Aerosol and nucleation research in support of NASA cloud physics experiments in space. [ice nuclei generator for the atmospheric cloud physics laboratory on Spacelab

    NASA Technical Reports Server (NTRS)

    Vali, G.; Rogers, D.; Gordon, G.; Saunders, C. P. R.; Reischel, M.; Black, R.

    1978-01-01

    Tasks performed in the development of an ice nucleus generator which, within the facility concept of the ACPL, would provide a test aerosol suitable for a large number and variety of potential experiments are described. The impact of Atmospheric Cloud Physics Laboratory scientific functional requirements on ice nuclei generation and characterization subsystems was established. Potential aerosol generating systems were evaluated with special emphasis on reliability, repeatability and general suitability for application in Spacelab. Possible contamination problems associated with aerosol generation techniques were examined. The ice nucleating abilities of candidate test aerosols were examined and the possible impact of impurities on the nucleating abilities of those aerosols were assessed as well as the relative merits of various methods of aerosol size and number density measurements.

  10. Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign

    NASA Astrophysics Data System (ADS)

    Mallet, M.; Dulac, F.; Formenti, P.; Nabat, P.; Sciare, J.; Roberts, G.; Pelon, J.; Ancellet, G.; Tanré, D.; Parol, F.; di Sarra, A.; Alados, L.; Arndt, J.; Auriol, F.; Blarel, L.; Bourrianne, T.; Brogniez, G.; Chazette, P.; Chevaillier, S.; Claeys, M.; D'Anna, B.; Denjean, C.; Derimian, Y.; Desboeufs, K.; Di Iorio, T.; Doussin, J.-F.; Durand, P.; Féron, A.; Freney, E.; Gaimoz, C.; Goloub, P.; Gómez-Amo, J. L.; Granados-Muñoz, M. J.; Grand, N.; Hamonou, E.; Jankowiak, I.; Jeannot, M.; Léon, J.-F.; Maillé, M.; Mailler, S.; Meloni, D.; Menut, L.; Momboisse, G.; Nicolas, J.; Podvin, J.; Pont, V.; Rea, G.; Renard, J.-B.; Roblou, L.; Schepanski, K.; Schwarzenboeck, A.; Sellegri, K.; Sicard, M.; Solmon, F.; Somot, S.; Torres, B.; Totems, J.; Triquet, S.; Verdier, N.; Verwaerde, C.; Wenger, J.; Zapf, P.

    2015-07-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx; http://charmex.lsce.ipsl.fr) is a collaborative research program federating international activities to investigate Mediterranean regional chemistry-climate interactions. A special observing period (SOP-1a) including intensive airborne measurements was performed in the framework of the Aerosol Direct Radiative Forcing on the Mediterranean Climate (ADRIMED) project during the Mediterranean dry season over the western and central Mediterranean basins, with a focus on aerosol-radiation measurements and their modeling. The SOP-1a took place from 11 June to 5 July 2013. Airborne measurements were made by both the ATR-42 and F-20 French research aircraft operated from Sardinia (Italy) and instrumented for in situ and remote-sensing measurements, respectively, and by sounding and drifting balloons, launched in Minorca. The experimental set-up also involved several ground-based measurement sites on islands including two ground-based reference stations in Corsica and Lampedusa and secondary monitoring sites in Minorca and Sicily. Additional measurements including lidar profiling were also performed on alert during aircraft operations at EARLINET/ACTRIS stations at Granada and Barcelona in Spain, and in southern Italy. Remote sensing aerosol products from satellites (MSG/SEVIRI, MODIS) and from the AERONET/PHOTONS network were also used. Dedicated meso-scale and regional modelling experiments were performed in relation to this observational effort. We provide here an overview of the different surface and aircraft observations deployed during the ChArMEx/ADRIMED period and of associated modeling studies together with an analysis of the synoptic conditions that determined the aerosol emission and transport. Meteorological conditions observed during this campaign (moderate temperatures and southern flows) were not favorable to produce high level of atmospheric pollutants nor

  11. Aerosol characteristics over Bay of Bengal during winter: Results from W-ICARB experiment

    NASA Astrophysics Data System (ADS)

    Sinha, P. R.; Manchanda, R. K.; Shankarnarayan, Sreenivasan; Babu, S. Suresh; Krishna Moorthy, K.; Kaskaoutis, D. G.

    2012-07-01

    The measurements of aerosol physical optical properties were carried out over placeBay of Bengal (BoB) during the period 27 December 2008--30 January 2009 as part of Winter Integrated Campaign on Aerosols, Gases and Radiation Budget (W-ICARB). The aerosol number size distribution at the surface was found to be bi-modal in the 72% of the cases with mode radius for the submicron aerosol of 0.13±0.01 μ m and 0.72±0.10μ m for the super-micron aerosol and the highest NT (350-550 cm{-3}), AOD500 (0.7}) and α 380-870 values were observed in western and northern BoB with lower values in the southern and parts of central BoB. The eastern part of BoB which was investigated for the first time showed concurrently high values of NT (200 and 300 cm-3), AOD500 (0.39±0.07) and α 380-870 (1.27±0.09). The aerosol types are examined using a classification scheme based on the relationship between aerosol load (AOD500) and particle size (α 380-870). The classification scheme indicated an extremely large fraction of fine-mode aerosols in turbid atmospheres, which is even larger than 90% in the western part of BoB and approaches 100% over eastern BoB. Furthermore, there is also an evidence of aerosol-size growth under more turbid conditions indicative of coagulation and/or humidification over specific BoB regions. The altitude variation of aerosol number density made for the first time over five different locations in BoB is found to be nearly steady at all locations within the convective boundary layer (up to 400 m), while above the aerosol concentration is found to decrease except for far east BoB. Examination of the air-mass back trajectories and the aerosol size distribution indicates that the aerosols advected from continental country-regionIndia have a pronounced natural (coarse mode) component, while those originating from placeEast Asia are in general accumulation origin.

  12. An overview of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx)

    NASA Astrophysics Data System (ADS)

    Dulac, François

    2014-05-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr) is a French initiative of the MISTRALS meta-programme (Mediterranean Integrated Studies at Regional And Locals Scales, http://www.mistrals-home.org). It federates a great number of national and international cooperative research actions aiming at a scientific assessment of the present and future state of the atmospheric environment in the Mediterranean Basin, and of its impacts on the regional climate, air quality, and marine biogeochemistry. The target is short-lived particulate and gaseous tropospheric trace species which are the cause of poor air quality events, have two-way interactions with climate, or impact the marine biogeochemistry, in a context of strong regional anthropogenic and climatic pressures. The six ChArMEx work packages include Emissions, Chemical processes and ageing, Transport processes and air quality, Aerosol-radiation-climate interactions, Deposition, and Present and future variability and trends. For several years, efforts have been deployed in several countries to develop (i) a network of relevant stations for atmospheric chemistry at background sites on islands and continental coasts around the basin and (ii) several intensive field campaigns including the operation of surface supersites and various instrumented mobile platforms (large and ultra-light aircraft, sounding and drifting balloons, ZeroCO2 sailboat). This presentation is an attempt to provide an overview of the various experimental, remote sensing and modelling efforts produced and to highlight major findings, by referencing more detailed ChArMEx presentations given in this conference and recently published or submitted papers. During the first phase of the project experimental efforts have been mainly concentrated on the western basin. Plans for the 2nd phase of ChArMEx, more dedicated towards the eastern basin, will also be given. In particular we plan to develop monitoring activities at

  13. Comparison of cloud residual and background aerosol particle composition during the hill cap cloud experiment HCCT 2010 in Central Germany

    NASA Astrophysics Data System (ADS)

    Roth, A.; Mertes, S.; van Pinxteren, D.; Klimach, T.; Herrmann, H.; Schneider, J.; Borrmann, S.

    2013-12-01

    Physical and chemical characterization of cloud residual and background aerosol particles as well as aerosol-cloud interactions were investigated during the Hill Cap Cloud Thuringia (HCCT) experiment in September and October 2010 on the mountain site Schmücke (938m a.s.l.) in Germany. Background aerosol particles were sampled by an interstitial inlet whereas cloud droplets from orographic clouds were collected by a counter flow virtual impactor (CVI). Chemical composition analysis and sizing of the particles was done by single particle mass spectrometry using the bipolar Aircraft-based Laser Ablation Aerosol Mass Spectrometer (ALABAMA, particle diameter range 150 nm - 900 nm; Brands et al., 2011) and by two Aerodyne Aerosol Mass Spectrometers (C-ToF, HR-ToF). Supplementary, the particle size distribution was measured with an optical particle counter (OPC, size range 0.25 μm - 32 μm). During the field campaign about 21000 positive and negative single particle mass spectra could be obtained from cloud residual particles and about 239000 from background aerosol particles. The data were clustered by means of the fuzzy c-means algorithm. The resulting clusters consisting of mass spectra with similar fragmentation patterns were, dependent on presence and combination of peaks, assigned to certain particle types. For both sampled particle types a large portion is internally mixed with nitrate and/or sulfate. This might be an explanation, why a comparison of the composition shows a higher fraction of soot particles and amine-containing particles among cloud residuals. Furthermore cloud residuals show a decreased fraction of particles being internally mixed only with nitrate (10%) compared to background aerosol particles (19%) of the same air masses, whereas the fraction of particles containing both nitrate and sulfate increases from 39% to 63% indicating cloud processing by uptake and oxidation of SO2 (Harris et al, 2013). Brands, M., Kamphus, M., Böttger, T., Schneider

  14. From Clusters to Atmospheric Aerosol Particles: Nucleation in the CLOUD Experiment at CERN

    NASA Astrophysics Data System (ADS)

    Baltensperger, Urs

    2015-03-01

    Globally, a significant source of cloud condensation nuclei for cloud formation is thought to originate from new particle formation (aerosol nucleation). Despite extensive research, many questions remain about the dominant nucleation mechanisms. Specifically, a quantitative understanding of the dependence of the nucleation rate on the concentration of the nucleating substances such as gaseous sulfuric acid, ammonia, water vapor and others has not been reached. This is of relevance for climate as the atmospheric concentrations of sulfuric acid, ammonia and other nucleating agents are strongly influenced by anthropogenic emissions. By providing extremely well controlled and essentially contaminant free conditions in the CLOUD chamber, we were able to show that indeed sulfuric acid is an important component for such new particle formation, however, for the typical temperatures encountered in the planetary boundary layer the concentrations of sulfuric acid are not high enough to explain the atmospheric observations. Moreover, the effect of ammonia, amines and oxidized organic molecules on the nucleation rate of sulfuric acid has been investigated in CLOUD so far. Recent developments in instrument technology such as the Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometer have allowed us to investigate the chemical composition of charged as well as neutral clusters during such nucleation experiments. The CLOUD (Cosmics Leaving OUtdoor Droplets) collaboration consists of 20 institutions from Europe and the United States and is funded by national funding institutions as well as the EU training network CLOUD-TRAIN (http://www.cloud-train.eu/).

  15. Stratospheric ozone variations in the equatorial region as seen in Stratiospheric Aerosol and Gas Experiment data

    SciTech Connect

    Shiotani, M.; Hasebe, F. |

    1994-07-01

    An analysis is made of equatorial ozone variations for 5 years, 1984-1989, using the ozone profile data derived from the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument. Attention is focused on the annual cycle and also on interannual variability, particularly the quasi-biennial oscillation (QBO) and El Nino-Southern Oscillation (ENSO) variations in the lower stratosphere, where the largest contribution to total column ozone takes place. The annual variation in zonal mean total ozone around the equator is composed of symmetric and asymmetric modes with respect to the equator, with maximum contributions being around 19 km for the symmetric mode and around 25 km for the asymmetric mode. The persistent zonal wavenumber 1 structure observed by the total ozone mapping spectrometer over the equator is almost missing in the SAGE-derived column amounts integrated in the stratosphere, suggesting a significant contribution from tropospheric ozone. Interannual variations in the equatorial ozone are dominated by the QBO above 20 km and the ENSO-related variation below 20 km. The ozone QBO is characterized by zonally uniform phase changes in association with the zonal wind QBO in the equatorial lower stratosphere. The ENSO-related ozone variation consists of both the east-west vacillation and the zonally uniform phase variation. During the El Nino event, the east-west contrast with positive (negative) deviations in the eastern (western) hemisphere is conspicuous, while the decreasing tendency of the zonal mean values is maximum at the same time.

  16. Stratospheric ozone variations in the equatorial region as seen in Stratiospheric Aerosol and Gas Experiment data

    NASA Technical Reports Server (NTRS)

    Shiotani, Masato; Hasebe, Fumio

    1994-01-01

    An analysis is made of equatorial ozone variations for 5 years, 1984-1989, using the ozone profile data derived from the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument. Attention is focused on the annual cycle and also on interannual variability, particularly the quasi-biennial oscillation (QBO) and El Nino-Southern Oscillation (ENSO) variations in the lower stratosphere, where the largest contribution to total column ozone takes place. The annual variation in zonal mean total ozone around the equator is composed of symmetric and asymmetric modes with respect to the equator, with maximum contributions being around 19 km for the symmetric mode and around 25 km for the asymmetric mode. The persistent zonal wavenumber 1 structure observed by the total ozone mapping spectrometer over the equator is almost missing in the SAGE-derived column amounts integrated in the stratosphere, suggesting a significant contribution from tropospheric ozone. Interannual variations in the equatorial ozone are dominated by the QBO above 20 km and the ENSO-related variation below 20 km. The ozone QBO is characterized by zonally uniform phase changes in association with the zonal wind QBO in the equatorial lower stratosphere. The ENSO-related ozone variation consists of both the east-west vacillation and the zonally uniform phase variation. During the El Nino event, the east-west contrast with positive (negative) deviations in the eastern (western) hemisphere is conspicuous, while the decreasing tendency of the zonal mean values is maximum at the same time.

  17. Comparison of stratospheric aerosol and gas experiment I (SAGE I) and Umkehr ozone profiles including a search for Umkehr aerosol effects

    SciTech Connect

    Newchurch, M.J.

    1986-01-01

    After briefly reviewing ozone depletion predictions from atmospheric models and results from trend analysis of Umkehr data, this paper outlines the Umkehr method for deducing the vertical profile of ozone and reviews the theoretical and empirical studies of the aerosol effect on Umkehr measurements. A brief description of the Stratospheric Aerosol and Gas Experiment I (SAGE I) is followed by a method for approximating the best representation of the conditions over the Umkehr ground site as seen by the SAGE I satellite. Using a spatially weighted average of SAGE I events derived from an autocorrelation analysis, the authors find 337 co-located SAGE I and Umkehr events. The approximate total column ozone measured by SAGE I is 5% higher than that measured by Umkehr on average. Most of this difference resides in Umkehr layer two, three, and four, while layers seven, eight, and nine contain small differences in average ozone content. Intercomparison with four other ozone studies indicates agreement between SAGE I and SBUV in most layers and at most Umkehr stations north of 30/sup 0/. However, significant differences in Umkehr layer eight between SAGE I and SBUV remain. Ozone differences between SAGE I and Umkehr are strong functions of both total column ozone and season in the lower layers but not in the upper layers.

  18. Overview of Asian Biomass Burning and Dust Aerosols Measured during the Dongsha Experiment in the Spring of 2010

    NASA Astrophysics Data System (ADS)

    Lin, N.; Tsay, S.; Wang, S.; Sheu, G.; Chi, K.; Lee, C.; Wang, J.

    2010-12-01

    The international campaign of Dongsha Experiment was conducted in the northern SE Asian region during March-May 2010. It is a pre-study of the Seven South East Asian Studies (7SEAS) which seeks to perform interdisciplinary research in the field of aerosol-meteorology and climate interaction in the Southeast Asian region, particularly for the impact of biomass burning on cloud, atmospheric radiation, hydrological cycle, and regional climate. Participating countries include Indonesia, Malaysia, Philippines, Singapore, Thailand, Taiwan, Vietnam, and USA (NASA, NRL, and NOAA). The main goals of Dongsha Experiment are (1) to develop the Dongsha Island (about 2 km2, 20°42'52" N, 116°43'51" E) in the South China Sea as an atmospheric observing platform of atmospheric chemistry, radiation and meteorological parameters, and (2) to characterize the chemical and physical properties of biomass burning aerosols in the northern SE Asian region. A monitoring network for ground-based measurements includes the Lulin Atmospheric Background Station (2,862 m MSL) in central Taiwan, Hen-Chun (coastal) in the very southern tip of Taiwan, Dongsha Island in South China Sea, Da Nang (near coastal region) in central Vietnam, and Chiang Mai (about 1,400 m, MSL) in northern Thailand. Besides, the Mobile Air Quality Station of Taiwan EPA and NASA/COMMIT were shipped to Dongsha Island for continuous measurements of CO, SO2, NOx, O3, and PM10, and aerosol optical and vertical profiles. Two Intensive Observation Periods (IOPs) for aerosol chemistry were conducted during 14-30 March and 10-20 April 2010, respectively. Ten aerosol samplers were deployed for each station for characterizing the compositions of PM2.5/PM10 (some for TSP) including water-soluble ions, metal elements, BC/OC, Hg and dioxins. Sampling tubes of VOCs were also deployed. Concurrent measurements with IOP-1, Taiwanese R/V also made a mission to South China Sea during 14-19 March. Enhanced sounding at Dongsha Island was

  19. Particle Morphology and Size Results from the Smoke Aerosol Measurement Experiment-2

    NASA Technical Reports Server (NTRS)

    Urban, David L.; Ruff, Gary A.; Greenberg, Paul S.; Fischer, David; Meyer, Marit; Mulholland, George; Yuan, Zeng-Guang; Bryg, Victoria; Cleary, Thomas; Yang, Jiann

    2012-01-01

    Results are presented from the Reflight of the Smoke Aerosol Measurement Experiment (SAME-2) which was conducted during Expedition 24 (July-September 2010). The reflight experiment built upon the results of the original flight during Expedition 15 by adding diagnostic measurements and expanding the test matrix. Five different materials representative of those found in spacecraft (Teflon, Kapton, cotton, silicone rubber and Pyrell) were heated to temperatures below the ignition point with conditions controlled to provide repeatable sample surface temperatures and air flow. The air flow past the sample during the heating period ranged from quiescent to 8 cm/s. The smoke was initially collected in an aging chamber to simulate the transport time from the smoke source to the detector. This effective transport time was varied by holding the smoke in the aging chamber for times ranging from 11 to 1800 s. Smoke particle samples were collected on Transmission Electron Microscope (TEM) grids for post-flight analysis. The TEM grids were analyzed to observe the particle morphology and size parameters. The diagnostics included a prototype two-moment smoke detector and three different measures of moments of the particle size distribution. These moment diagnostics were used to determine the particle number concentration (zeroth moment), the diameter concentration (first moment), and the mass concentration (third moment). These statistics were combined to determine the diameter of average mass and the count mean diameter and, by assuming a log-normal distribution, the geometric mean diameter and the geometric standard deviations can also be calculated. Overall the majority of the average smoke particle sizes were found to be in the 200 nm to 400 nm range with the quiescent cases producing some cases with substantially larger particles.

  20. LASE measurements of water vapor and aerosol profiles during the Plains Elevated Convection at Night (PECAN) field experiment

    NASA Astrophysics Data System (ADS)

    Nehrir, A. R.; Ferrare, R. A.; Kooi, S. A.; Butler, C. F.; Notari, A.; Hair, J. W.; Collins, J. E., Jr.; Ismail, S.

    2015-12-01

    The Lidar Atmospheric Sensing Experiment (LASE) system was deployed on the NASA DC-8 aircraft during the Plains Elevated Convection At Night (PECAN) field experiment, which was conducted during June-July 2015 over the central and southern plains. LASE is an active remote sensor that employs the differential absorption lidar (DIAL) technique to measure range resolved profiles of water vapor and aerosols above and below the aircraft. The DC-8 conducted nine local science flights from June 30- July 14 where LASE sampled water vapor and aerosol fields in support of the PECAN primary science objectives relating to better understanding nocturnal Mesoscale Convective Systems (MCSs), Convective Initiation (CI), the Low Level Jet (LLJ), bores, and to compare different airborne and ground based measurements. LASE observed large spatial and temporal variability in water vapor and aerosol distributions in advance of nocturnal MCSs, across bores resulting from MCS outflow boundaries, and across the LLJ associated with the development of MCSs and CI. An overview of the LASE data collected during the PECAN field experiment will be presented where emphasis will be placed on variability of water vapor profiles in the vicinity of severe storms and intense convection in the central and southern plains. Preliminary comparisons show good agreement between coincident LASE and radiosonde water vapor profiles. In addition, an advanced water vapor DIAL system being developed at NASA Langley will be discussed.

  1. The Joint Aerosol-Monsoon Experiment (JAMEX): A Core Element for the Asian Monsoon Year (2008-2009)

    NASA Technical Reports Server (NTRS)

    Lau, WIlliam K. M.

    2007-01-01

    The objective of the Joint Aerosol-Monsoon Experiment (JAMEX) is to unravel the physical mechanisms and multi-scale interactions associated with aerosol-monsoon water cycle in the Asian Indo-Paczj?c region towards improved prediction of rainfall in land regions of the Asian monsoon. JAMEX will be planned as a five-year (2007-201 1) multi-national aerosol-monsoon research project, aimed at promoting collaboration, partnership and alignment of ongoing and planned national and international programs. Two coordinated special observing periods (SOP), covering the pre-monsoon (April-May) and the monsoon (June-August) periods is tentatively targeted for 2008 and 2009. The major work on validation and reference site coordination will take place in 2007 through the spring of 2008. A major science workshop is planned after SOP-I1 in 2010. Modeling and satellite data utilization studies will continue throughout the entire period to help in design of the observation arrays and measurement platforms for SOPS. The tentative time schedule, including milestones and research activities is shown in Fig. 1. One of the unique aspects of JAMEX is that it stems from grass-root scientific and societal imperatives, and it bridges a gap in existing national and international research programs. Currently we have identified 10 major national and international projects/programs separately for aerosols and monsoon research planned in the next five years in China, India, Japan, Italy, and the US, that could be potential contributors or partners with JAMEX. These include the Asian-Indo- Pacific Ocean (AIPO) Project and Aerosol Research Project from China, Monsoon Asian Hydro- Atmospheric Science Research and predication Initiative (MAHASRI) from Japan, Continental Tropical Convergence Zone (CTCZ) and Severe Thunderstorm: Observations and Regional Modeling (STORM) from India, Share-Asia from Italy, Atmospheric Brown Cloud (ABC), Pacific Aerosol-Cloud-Dust Experiment (PACDEX), East Asia Study of

  2. The Joint Aerosol-Monsoon Experiment (JAMEX): A Core Element for the Asian Monsoon Year (2008-2009)

    NASA Technical Reports Server (NTRS)

    Lau, William K.M.

    2007-01-01

    The objective of the Joint Aerosol-Monsoon Experiment (JAMEX) is to unravel the physical mechanisms and multi-scale interactions associated with aerosol-monsoon water cycle in the Asian Indo-Pacific region towards improved prediction of rainfall in land regions of the Asian monsoon. JAMEX will be planned as a five-year (2007-201 1) multi-national aerosol-monsoon research project, aimed at promoting collaboration, partnership and alignment of ongoing and planned national and international programs. Two coordinated special observing periods (SOP), covering the pre-monsoon (April-May) and the monsoon (June-August) periods is tentatively targeted for 2008 and 2009. The major work on validation and reference site coordination will take place in 2007 through the spring of 2008. A major science workshop is planned after SOP-I1 in 2010. Modeling and satellite data utilization studies will continue throughout the entire period to help in design of the observation arrays and measurement platforms for SOPS. The tentative time schedule, including milestones and research activities is shown in Fig. 1. One of the unique aspects of JAMEX is that it stems from grass-root scientific and societal imperatives, and it bridges a gap in existing national and international research programs. Currently we have identified 10 major national and international projects/programs separately for aerosols and monsoon research planned in the next five years in China, India, Japan, Italy, and the US, that could be potential contributors or partners with JAMEX. These include the Asian-Indo- Pacific Ocean (AIPO) Project and Aerosol Research Project from China, Monsoon Asian Hydro- Atmospheric Science Research and predication Initiative (MAHASRI) from Japan, Continental Tropical Convergence Zone (CTCZ) and Severe Thunderstorm: Observations and Regional Modeling (STORM) from India, Share-Asia from Italy, Atmospheric Brown Cloud (ABC), Pacific Aerosol-Cloud-Dust Experiment (PACDEX), East Asia Study of

  3. Exploring Atmospheric Aqueous Chemistry (and Secondary Organic Aerosol Formation) through OH Radical Oxidation Experiments, Droplet Evaporation and Chemical Modeling

    NASA Astrophysics Data System (ADS)

    Turpin, B. J.; Kirkland, J. R.; Lim, Y. B.; Ortiz-Montalvo, D. L.; Sullivan, A.; Häkkinen, S.; Schwier, A. N.; Tan, Y.; McNeill, V. F.; Collett, J. L.; Skog, K.; Keutsch, F. N.; Sareen, N.; Carlton, A. G.; Decesari, S.; Facchini, C.

    2013-12-01

    Gas phase photochemistry fragments and oxidizes organic emissions, making water-soluble organics ubiquitous in the atmosphere. My group and others have found that several water-soluble compounds react further in the aqueous phase forming low volatility products under atmospherically-relevant conditions (i.e., in clouds, fogs and wet aerosols). Thus, secondary organic aerosol can form as a result of gas followed by aqueous chemistry (aqSOA). We have used aqueous OH radical oxidation experiments coupled with product analysis and chemical modeling to validate and refine the aqueous chemistry of glyoxal, methylglyoxal, glycolaldehyde, and acetic acid. The resulting chemical model has provided insights into the differences between oxidation chemistry in clouds and in wet aerosols. Further, we conducted droplet evaporation experiments to characterize the volatility of the products. Most recently, we have conducted aqueous OH radical oxidation experiments with ambient mixtures of water-soluble gases to identify additional atmospherically-important precursors and products. Specifically, we scrubbed water-soluble gases from the ambient air in the Po Valley, Italy using four mist chambers in parallel, operating at 25-30 L min-1. Aqueous OH radical oxidation experiments and control experiments were conducted with these mixtures (total organic carbon ≈ 100 μM-C). OH radicals (3.5E-2 μM [OH] s-1) were generated by photolyzing H2O2. Precursors and products were characterized using electrospray ionization mass spectrometry (ESI-MS), ion chromatography (IC), IC-ESI-MS, and ultra high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Chemical modeling suggests that organic acids (e.g., oxalate, pyruvate, glycolate) are major products of OH radical oxidation at cloud-relevant concentrations, whereas organic radical - radical reactions result in the formation of oligomers in wet aerosols. Products of cloud chemistry and droplet evaporation have

  4. Carbonaceous aerosols over the Indian Ocean during the Indian Ocean Experiment (INDOEX): Chemical characterization, optical properties, and probable sources

    NASA Astrophysics Data System (ADS)

    Mayol-Bracero, O. L.; Gabriel, R.; Andreae, M. O.; Kirchstetter, T. W.; Novakov, T.; Ogren, J.; Sheridan, P.; Streets, D. G.

    2002-10-01

    We measured carbonaceous material and water-soluble ionic species in the fine fraction (Dp < 1.3 μm) of aerosol samples collected on NCAR's C-130 aircraft during the intensive field phase (February-March 1999) of the Indian Ocean Experiment (INDOEX). Polluted layers were present over most of the study region north of the equator at altitudes up to 3.2 km. The estimated aerosol mass (sum of carbonaceous and soluble ionic aerosol components) of fine-mode particles in these layers was 15.3 ± 7.9 μg m-3. The major components were particulate organic matter (POM, 35%), SO42- (34%), black carbon (BC, 14%), and NH4+ (11%). The main difference between the composition of the marine boundary layer (MBL, 0 to ˜1.2 km), and the overlying residual continental boundary layer (1.2 to ˜3.2 km) was a higher abundance of SO42- relative to POM in the MBL, probably due to a faster conversion of SO2 into SO42- in the MBL. Our results show that carbon is a major, and sometimes dominant, contributor to the aerosol mass and that its contribution increases with altitude. Low variability was observed in the optical properties of the aerosol in the two layers. Regression analysis of the absorption coefficient at 565 nm on BC mass (BC < 4.0 μg C m-3) yielded a specific absorption cross section of 8.1 ± 0.7 m2 g-1 for the whole period. The unusually high fraction of BC and the good correlation between the absorption coefficient and BC suggest that BC was responsible for the strong light absorption observed for the polluted layers during INDOEX. High correlation between BC and total carbon (TC) (r2 = 0.86) suggest that TC is predominantly of primary origin. Good correlations were also found between the scattering coefficient at 550 nm and the estimated aerosol mass for the fine fraction. These yielded a specific scattering cross section of 4.9 ± 0.4 m2 g-1. The observed BC/TC, BC/OC, SO42-/BC, and K+/BC ratios were fairly constant throughout the period. These ratios suggest that between

  5. The Stratospheric Aerosol and Gas Experiment III/International Space Station Mission: Science Objectives and Mission Status

    NASA Astrophysics Data System (ADS)

    Eckman, R.; Zawodny, J. M.; Cisewski, M. S.; Flittner, D. E.; McCormick, M. P.; Gasbarre, J. F.; Damadeo, R. P.; Hill, C. A.

    2015-12-01

    The Stratospheric Aerosol and Gas Experiment III/International Space Station (SAGE III/ISS) is a strategic climate continuity mission which was included in NASA's 2010 plan, "Responding to the Challenge of Climate and Environmental Change: NASA's Plan for a Climate-Centric Architecture for Earth Observations and Applications from Space." SAGE III/ISS continues the long-term, global measurements of trace gases and aerosols begun in 1979 by SAGE I and continued by SAGE II and SAGE III on Meteor 3M. Using a well characterized occultation technique, the SAGE III instrument's spectrometer will measure vertical profiles of ozone, aerosols, water vapor, nitrogen dioxide, and other trace gases relevant to ozone chemistry. The mission will launch in 2016 aboard a Falcon 9 spacecraft.The primary objective of SAGE III/ISS is to monitor the vertical distribution of aerosols, ozone, and other trace gases in the Earth's stratosphere and troposphere to enhance our understanding of ozone recovery and climate change processes in the stratosphere and upper troposphere. SAGE III/ISS will provide data necessary to assess the state of the recovery in the distribution of ozone, extend the SAGE III aerosol measurement record that is needed by both climate models and ozone models, and gain further insight into key processes contributing to ozone and aerosol variability. The multi-decadal SAGE ozone and aerosol data sets have undergone intense community scrutiny for accuracy and stability. SAGE ozone data have been used to monitor the effectiveness of the Montreal Protocol.The ISS inclined orbit of 51.6 degrees is ideal for SAGE III measurements because the orbit permits solar occultation measurement coverage to approximately +/- 70 degrees of latitude. SAGE III/ISS will make measurements using the solar occultation measurement technique, lunar occultation measurement technique, and the limb scattering measurement technique. In this presentation, we describe the SAGE III/ISS mission, its

  6. An Overview of Regional Experiments on Biomass Burning Aerosols and Related Pollutants in Southeast Asia: From BASE-ASIA and the Dongsha Experiment to 7-SEAS

    NASA Technical Reports Server (NTRS)

    Lin, Neng-Huei; Tsay, Si-Chee; Maring, Hal B.; Yen, Ming-Cheng; Sheu, Guey-Rong; Wang, Sheng-Hsiang; Chi, Kai Hsien; Chuang, Ming-Tung; Ou-Yang, Chang-Feng; Fu, Joshua S.; Reid, Jeffrey S.; Lee, Chung-Te; Wang, Lin-Chi; Wang, Jia-Lin; Hsu, Christina N.; Sayer, Andrew M.; Holben, Brent N.; Chu, Yu-Chi; Nguyen, Xuan Anh; Sopajaree, Khajornsak; Chen, Shui-Jen; Cheng, Man-Ting; Tsuang, Ben-Jei; Tsai, Chuen-Jinn; Peng, Chi-Ming; Schnell, Russell C.; Conway, Tom; Chang, Chang-Tang; Lin, Kuen-Song; Tsai, Ying I.; Lee, Wen-Jhy; Chang, Shuenn-Chin; Liu, Jyh-Jian; Chang, Wei-Li; Huang, Shih-Jen; Lin, Tang-Huang; Liu, Gin-Rong

    2013-01-01

    By modulating the Earth-atmosphere energy, hydrological and biogeochemical cycles, and affecting regional-to-global weather and climate, biomass burning is recognized as one of the major factors affecting the global carbon cycle. However, few comprehensive and wide-ranging experiments have been conducted to characterize biomass-burning pollutants in Southeast Asia (SEA) or assess their regional impact on meteorology, the hydrological cycle, the radiative budget, or climate change. Recently, BASEASIA (Biomass-burning Aerosols in South-East Asia: Smoke Impact Assessment) and the 7-SEAS (7- South-East Asian Studies) Dongsha Experiment were conducted during the spring seasons of 2006 and 2010 in northern SEA, respectively, to characterize the chemical, physical, and radiative properties of biomass-burning emissions near the source regions, and assess their effects. This paper provides an overview of results from these two campaigns and related studies collected in this special issue, entitled Observation, modeling and impact studies of biomass burning and pollution in the SE Asian Environment. This volume includes 28 papers, which provide a synopsis of the experiments, regional weatherclimate, chemical characterization of biomass-burning aerosols and related pollutants in source and sink regions, the spatial distribution of air toxics (atmospheric mercury and dioxins) in source and remote areas, a characterization of aerosol physical, optical, and radiative properties, as well as modeling and impact studies. These studies, taken together, provide the first relatively complete dataset of aerosol chemistry and physical observations conducted in the sourcesink region in the northern SEA, with particular emphasis on the marine boundary layer and lower free troposphere (LFT). The data, analysis and modeling included in these papers advance our present knowledge of source characterization of biomass-burning pollutants near the source regions as well as the physical and

  7. Intercomparison of stratospheric water vapor observed by satellite experiments - Stratospheric Aerosol and Gas Experiment II versus Limb Infrared Monitor of the Stratosphere and Atmospheric Trace Molecule Spectroscopy

    NASA Technical Reports Server (NTRS)

    Chiou, E. W.; Mccormick, M. P.; Mcmaster, L. R.; Chu, W. P.; Larsen, J. C.; Rind, D.; Oltmans, S.

    1993-01-01

    A comparison is made of the stratospheric water vapor measurements made by the satellite sensors of the Stratospheric Aerosol and Gas Experiment II (SAGE II), the Nimbus-7 LIMS, and the Spacelab 3 Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment. It was found that, despite differences in the measurement techniques, sampling bias, and observational periods, the three experiments have disclosed a generally consistent pattern of stratospheric water vapor distribution. The only significant difference occurs at high southern altitudes in May below 18 km, where LIMS measurements were 2-3 ppmv greater than those of SAGE II and ATMOS.

  8. A comparison of the Stratospheric Aerosol and Gas Experiment II tropospheric water vapor to radiosonde measurements

    SciTech Connect

    Larsen, J.C.; Chiou, E.W. ); Chu, W.P.; McCormick, M.P.; McMaster, L.R. ); Oltmans, S. ); Rind, D. )

    1993-03-20

    Upper tropospheric Stratospheric Aerosol and Gas Experiment II (SAGE II) water vapor observations are compared to correlative radiosonde observations and radiosonde based climatologies. The SAGE II 1987 monthly zonal mean water vapor climatology is compared to both the Global Atmospheric Circulation Statistics (1963-1973) climatology and to the 1987 radiosonde climatology. The clear sky SAGE II climatology is found to be approximately half the level of both the clear/cloudy sky radiosonde climatologies. To determine whether this is realistic for these two different climatologies or includes additional observational and instrumental biases, the authors took the 1987 radiosonde data set and identified approximately 800 correlative profile pairs. The observational biases inherent to SAGE II and the radiosondes produce a set of profile pairs characteristic of clear sky, land conditions. A critical review of the radiosonde measurement capability was carried out to establish the operating range and accuracy in the upper troposphere. The authors show that even with tight coincidence criterion, the quality of the profile pair comparisons varies considerably because of strong water vapor variability occurring on small time and space scales. Annual zonal means calculated from the set of profile pairs again finds SAGE II significantly drier in many latitude bands. Resolving the radiosonde data base by hygrometer type shows this to be true for all hygrometers except for the thin film capacitive type (Vaisala Humicap). For this hygrometer, between 4.5 and 6.5 km SAGE II is drier by approximately 25.%, and from 8.5 to 11.5 km they are nearly equivalent when global annual means are compared. The good agreement with the Vaisala Humicap, currently the most accurate and responsive hygrometer in operational use, suggests existing radiosonde climatologies contain a significant moist bias in the upper troposphere. 31 refs., 16 figs., 6 tabs.

  9. Organic Composition of Size-Segregated Aerosols Sampled During the 2002 Bay Regional Atmospheric Chemistry Experiment (BRACE), Florida, USA

    NASA Astrophysics Data System (ADS)

    Tremblay, R. T.; Zika, R. G.

    2003-04-01

    Aerosol samples were collected for the analysis of organic source markers using non-rotating Micro Orifice Uniform Deposit Impactors (MOUDI) as part of the Bay Regional Atmospheric Chemistry Experiment (BRACE) in Tampa, FL, USA. Daily samples were collected 12 m above ground at a flow rate of 30 lpm throughout the month of May 2002. Aluminum foil discs were used to sample aerosol size fractions with aerodynamic cut diameter of 18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.17 and 0.093 um. Samples were solvent extracted using a mixture of dichloromethane/acetone/hexane, concentrated and then analyzed using gas chromatography-mass spectrometry (GC/MS). Low detection limits were achieved using a HP Programmable Temperature Vaporizing inlet (PTV) and large volume injections (80ul). Excellent chromatographic resolution was obtained using a 60 m long RTX-5MS, 0.25 mm I.D. column. A quantification method was built for over 90 organic compounds chosen as source markers including straight/iso/anteiso alkanes and polycyclic aromatic hydrocarbons (PAH). The investigation of potential aerosol sources for different particle sizes using known organic markers and source profiles will be presented. Size distributions of carbon preference indices (CPI), percent wax n-alkanes (%WNA) and concentration of selected compounds will be discussed. Also, results will be compared with samples acquired in different environments including the 1999 Atlanta SuperSite Experiment, GA, USA.

  10. Discrimination of water, ice and aerosols by light polarisation in the CLOUD experiment

    NASA Astrophysics Data System (ADS)

    Nichman, L.; Fuchs, C.; Järvinen, E.; Ignatius, K.; Höppel, N. F.; Dias, A.; Heinritzi, M.; Simon, M.; Tröstl, J.; Wagner, A. C.; Wagner, R.; Williamson, C.; Yan, C.; Bianchi, F.; Connolly, P. J.; Dorsey, J. R.; Duplissy, J.; Ehrhart, S.; Frege, C.; Gordon, H.; Hoyle, C. R.; Kristensen, T. B.; Steiner, G.; Donahue, N. M.; Flagan, R.; Gallagher, M. W.; Kirkby, J.; Möhler, O.; Saathoff, H.; Schnaiter, M.; Stratmann, F.; Tomé, A.

    2015-11-01

    Cloud microphysical processes involving the ice phase in tropospheric clouds are among the major uncertainties in cloud formation, weather and General Circulation Models (GCMs). The simultaneous detection of aerosol particles, liquid droplets, and ice crystals, especially in the small cloud-particle size range below 50 μm, remains challenging in mixed phase, often unstable ice-water phase environments. The Cloud Aerosol Spectrometer with Polarisation (CASPOL) is an airborne instrument that has the ability to detect such small cloud particles and measure their effects on the backscatter polarisation state. Here we operate the versatile Cosmics-Leaving-OUtdoor-Droplets (CLOUD) chamber facility at the European Organisation for Nuclear Research (CERN) to produce controlled mixed phase and other clouds by adiabatic expansions in an ultraclean environment, and use the CASPOL to discriminate between different aerosols, water and ice particles. In this paper, optical property measurements of mixed phase clouds and viscous Secondary Organic Aerosol (SOA) are presented. We report observations of significant liquid - viscous SOA particle polarisation transitions under dry conditions using CASPOL. Cluster analysis techniques were subsequently used to classify different types of particles according to their polarisation ratios during phase transition. A classification map is presented for water droplets, organic aerosol (e.g., SOA and oxalic acid), crystalline substances such as ammonium sulphate, and volcanic ash. Finally, we discuss the benefits and limitations of this classification approach for atmospherically relevant concentration and mixtures with respect to the CLOUD 8-9 campaigns and its potential contribution to Tropical Troposphere Layer (TTL) analysis.

  11. A study on the extent of neutralization of sulphate aerosol through laboratory and field experiments using an ATOFMS and a GPIC

    NASA Astrophysics Data System (ADS)

    Yao, Xiaohong; Rehbein, Peter J. G.; Lee, Colin J.; Evans, Greg J.; Corbin, Joel; Jeong, Cheol-Heon

    2011-11-01

    Extent of neutralization (EoN) of atmospheric aerosol is an important parameter in understanding related nucleation mechanisms, acid-catalyzed reactions and gas-aerosol partitioning. Ion m/ z -195 (HSOHSO4-) detected by the Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) has been used as an indicator of incompletely-neutralized sulphate aerosol, but there are no laboratory data to support this assumption. In this study, experiments using artificially generated sulphuric acid nucleated aerosol and metal sulphate aerosol across a range of EoN found that the peak area ratio and hit ratio of ion m/ z -195 (HSOHSO4-) to ion m/ z -97 (HSO4-) detected by the ATOFMS increased with decreasing EoN. Area ratio and hit ratio are sensitive to EoN at the low and high value zones, respectively. In ambient air measured by the ATOFMS and a Gas Particle Ion Chromatograph (GPIC) in Toronto, Canada, ion m/ z -195 was always detected in ammonium sulphate aerosol, and its hit number and peak area varied widely, regardless of EoN indicated by the equivalent ratio of NH4+ to (SO42-+NO3-). Thus, ion m/ z -195 alone is not an indicator of acidic sulphate aerosol. The combined approach using the ATOFMS and the GPIC found that cloud-processing formed incompletely-neutralized acidic sulphate aerosol in 2 out of 35 days sampled in winter in Toronto, Canada. It is interesting that the two episodes both occurred at night. Formation of incompletely-neutralized acidic sulphate aerosol caused a decrease in the concentration of particulate nitrate. This can be explained by acidic sulphate aerosol reacting with ammonium nitrate, leading to the release of HNO 3 to the gas phase. It was also found that the GPIC results occasionally suffered a positive artifact of NH4+ concentration caused by the clogging-induced high back-pressure in the instrument.

  12. Experiments probing the influence of air exchange rates on secondary organic aerosols derived from indoor chemistry

    NASA Astrophysics Data System (ADS)

    Weschler, Charles J.; Shields, Helen C.

    Reactions between ozone and terpenes have been shown to increase the concentrations of submicron particles in indoor settings. The present study was designed to examine the influence of air exchange rates on the concentrations of these secondary organic aerosols as well as on the evolution of their particle size distributions. The experiments were performed in a manipulated office setting containing a constant source of d-limonene and an ozone generator that was remotely turned "on" or "off" at 6 h intervals. The particle number concentrations were monitored using an optical particle counter with eight-channels ranging from 0.1-0.2 to>2.0 μm diameter. The air exchange rates during the experiments were either high (working hours) or low (non-working hours) and ranged from 1.6 to>12 h -1, with intermediate exchange rates. Given the emission rates of ozone and d-limonene used in these studies, at an air exchange rate of 1.6 h -1 particle number concentration in the 0.1-0.2 μm size-range peaked 1.2 h after the ozone generator was switched on. In the ensuing 4.8 h particle counts increased in successive size-ranges up to the 0.5-0.7 μm diameter range. At higher air exchange rates, the resulting concentrations of total particles and particle mass (calculated from particle counts) were smaller, and at exchange rates exceeding 12 h -1, no excess particle formation was detectable with the instrument used in this study. Particle size evolved through accretion and, in some cases, coagulation. There was evidence for coagulation among particles in the smallest size-range at low air exchange rates (high particle concentrations) but no evidence of coagulation was apparent at higher air exchange rates (lower particle concentrations). At higher air exchange rates the particle count or size distributions were shifted towards smaller particle diameters and less time was required to achieve the maximum concentration in each of the size-ranges where discernable particle growth

  13. Smog chamber experiments to investigate Henry's law constants of glyoxal using different seed aerosols

    NASA Astrophysics Data System (ADS)

    Jakob, Ronit

    2014-05-01

    Aerosols play an important role in the chemistry and physics of the atmosphere. Hence, they have a direct as well as an indirect impact on the earth's climate. Depending on their formation, one distinguishes between primary and secondary aerosols[1]. Important groups within the secondary aerosols are the secondary organic aerosols (SOAs). In order to improve predictions about these impacts on the earth's climate the existing models need to be optimized, because they still underestimate SOA formation[2]. Glyoxal, the smallest α-dicarbonyl, not only acts as a tracer for SOA formation but also as a direct contributor to SOA. Because glyoxal has such a high vapour pressure, it was common knowledge that it does not take part in gas-particle partitioning and therefore has no impact on direct SOA formation. However, the Henry's law constant for glyoxal is surprisingly high. This has been explained by the hydration of the aldehyde groups, which means that a species with a lower vapour pressure is produced. Therefore the distribution of glyoxal between gas- and particle phase is atmospherically relevant and the direct contribution of glyoxal to SOA can no longer be neglected. A high salt concentration present in chamber seed aerosols leads to an enhanced glyoxal uptake into the particle. This effect is called "salting-in". The salting effect depends on the composition of the seed aerosol as well as the soluble compound. For very polar compounds, like glyoxal, a "salting-in" is observed[3]. Glyoxal particle formation during a smog chamber campaign at Paul-Scherrer-Institut (PSI) in Switzerland was examined using different seed aerosols such as ammonium sulfate, sodium chloride and sodium nitrate. The aim of this campaign was to investigate Henry's law constants for different seed aerosols. During the campaign filter samples were taken to investigate the amount of glyoxal in the particle phase. After filter extraction, the analyte was derivatized and measured using UHPLC

  14. Generation of Mie size microdroplet aerosols with applications in laser-driven fusion experiments.

    PubMed

    Higginbotham, A P; Semonin, O; Bruce, S; Chan, C; Maindi, M; Donnelly, T D; Maurer, M; Bang, W; Churina, I; Osterholz, J; Kim, I; Bernstein, A C; Ditmire, T

    2009-06-01

    We have developed a tunable source of Mie scale microdroplet aerosols that can be used for the generation of energetic ions. To demonstrate this potential, a terawatt Ti:Al2O3 laser focused to 2 x 10(19) W/cm2 was used to irradiate heavy water (D2O) aerosols composed of micron-scale droplets. Energetic deuterium ions, which were generated in the laser-droplet interaction, produced deuterium-deuterium fusion with approximately 2 x 10(3) fusion neutrons measured per joule of incident laser energy. PMID:19566203

  15. Aerosol composition, chemistry, and source characterization during the 2008 VOCALS Experiment

    SciTech Connect

    Lee, Y.; Springston, S.; Jayne, J.; Wang, J.; Senum, G.; Hubbe, J.; Alexander, L.; Brioude, J.; Spak, S.; Mena-Carrasco, M.; Kleinman, L.; Daum, P.

    2010-03-15

    Chemical composition of fine aerosol particles over the northern Chilean coastal waters was determined onboard the U.S. DOE G-1 aircraft during the VOCALS (VAMOS Ocean-Cloud-Atmosphere-Land Study) field campaign between October 16 and November 15, 2008. SO42-, NO3-, NH4+, and total organics (Org) were determined using an Aerodyne Aerosol Mass Spectrometer, and SO42-, NO3-, NH4+, Na+, Cl-, CH3SO3-, Mg2+, Ca2+, and K+ were determined using a particle-into-liquid sampler-ion chromatography technique. The results show the marine boundary layer (MBL) aerosol mass was dominated by non- sea-salt SO42- followed by Na+, Cl-, Org, NO3-, and NH4+, in decreasing importance; CH3SO3-, Ca2+, and K+ rarely exceeded their respective limits of detection. The SO42- aerosols were strongly acidic as the equivalent NH4+ to SO42- ratio was only {approx}0.25 on average. NaCl particles, presumably of sea-salt origin, showed chloride deficits but retained Cl- typically more than half the equivalency of Na+, and are externally mixed with the acidic sulfate aerosols. Nitrate was observed only on sea-salt particles, consistent with adsorption of HNO3 on sea-salt aerosols, responsible for the Cl- deficit. Dust particles appeared to play a minor role, judging from the small volume differences between that derived from the observed mass concentrations and that calculated based on particle size distributions. Because SO42- concentrations were substantial ({approx}0.5 - {approx}3 {micro}g/m3) with a strong gradient (highest near the shore), and the ocean-emitted dimethylsulfide and its unique oxidation product, CH3SO3-, were very low (i.e., {le} 40 parts per trillion and <0.05 {micro}g/m3, respectively), the observed SO42- aerosols are believed to be primarily of terrestrial origin. Back trajectory calculations indicate sulfur emissions from smelters and power plants along coastal regions of Peru and Chile are the main sources of these SO4- aerosols. However, compared to observations, model

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  17. Aerosol ultraviolet absorption experiment (2002 to 2004), part 1: ultraviolet multifilter rotating shadowband radiometer calibration and intercomparison with CIMEL sunphotometers

    NASA Astrophysics Data System (ADS)

    Krotkov, Nickolay A.; Bhartia, Pawan K.; Herman, Jay R.; Slusser, James R.; Labow, Gordon J.; Scott, Gwendolyn R.; Janson, George T.; Eck, Tom; Holben, Brent N.

    2005-04-01

    Radiative transfer calculations of UV irradiance from total ozone mapping spectrometer (TOMS) satellite data are frequently overestimated compared to ground-based measurements because of the presence of undetected absorbing aerosols in the planetary boundary layer. To reduce these uncertainties, an aerosol UV absorption closure experiment has been conducted at the National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC) site in Greenbelt, Maryland, using 17 months of data from a shadowband radiometer [UV-multifilter rotating shadowband radiometer (UV-MFRSR), U.S. Department of Agriculture (USDA) UV-B Monitoring and Research Network] colocated with a group of three sun-sky CIMEL radiometers [rotating reference instruments of the NASA Aerosol Robotic Network (AERONET)]. We describe an improved UV-MFRSR on-site calibration method augmented by AERONET-CIMEL measurements of aerosol extinction optical thickness (τa) interpolated or extrapolated to the UV-MFRSR wavelengths and measurement intervals. The estimated τa is used as input to a UV-MFRSR spectral-band model, along with independent column ozone and surface pressure measurements, to estimate zero air mass voltages V0 in three longer wavelength UV-MFRSR channels (325, 332, 368 nm). Daily mean , estimates and standard deviations are obtained for cloud-free conditions and compared with the on-site UV-MFRSR Langley plot calibration method. By repeating the calibrations on clear days, relatively good stability (+/-2% in ) is found in summer, with larger relative changes in fall-winter seasons.

  18. The Influence of Urban Emissions on Background Aerosols and Trace Gases in Amazonia as Seen in the GoAmazon2014/2015 Experiment.

    NASA Astrophysics Data System (ADS)

    Artaxo, P.; Martin, S. T.; Barbosa, H. M.; Brito, J.; Carbone, S.; Rizzo, L. V.; Andreae, M. O.; Pöhlker, C.; Souza, R. A. F. D.

    2015-12-01

    As part of the GoAmazon2014/2015 experiment, several aerosol and trace gas monitoring stations are being operated for two years before and after the Manaus urban plume in Central Amazonia. Three sites are being operated in pristine conditions, with atmospheric properties under natural biogenic conditions. These three sites named T0 are ATTO (Amazon Tall Tower Observatory), ZF2 and EMBRAPA. After the air masses are exposed to the Manaus plume, one site (called T2) is being operated under the direct influence of the Manaus plume at 5 Km downwind. Finally, at about 150 Km downwind of Manaus is the T3 Manacapuru site. Aerosol chemical composition is being analysed using filters for fine (PM2.5) and coarse mode aerosol as well as three Aerodyne ACSM (Aerosol Chemical Speciation Monitors) instruments. Optical properties were measured with several AE33 aethalometers and MAAP, and multi wavelengths nephelometers. Aerosol size distribution is determined using scanning mobility particle sizers. The aerosol column is measures using AERONET sunphotometers before and after the Manaus plume, as well as several Lidar systems. The three sites before the Manaus plume show remarkable similar variability in aerosol concentrations and optical properties. This pattern is very different at the T2 site, with large aerosol concentrations enhancing aerosol absorption and scattering significantly as a result of the Manaus pollution plume. The aerosol is very oxidized before being exposed to the Manaus plume, and this pattern changes significantly for T2 and T3 sites, with a much higher presence of less oxidized aerosol. Typical ozone concentrations at mid-day before Manaus plume is a low 10-12 ppb, value that changes to 50-70 ppb for air masses suffering the influence of Manaus plume. Aerosol size distribution also change significantly, with stronger presence of nucleation mode particles. A detailed comparison of aerosol characteristics and composition for the several sites will be

  19. Large gradients in aerosol induced atmospheric heating rate over oceanic regions around India: Results from the ICARB Experiment of ISRO-GBP

    NASA Astrophysics Data System (ADS)

    Babu, S. Suresh; Krishna Moorthy, K.; Nair, Vijayakumar S.; K, Satheesh S.

    The importance of aerosol absorption and the resulting heating of the lower atmosphere over south Asia are being increasingly investigated in the context of regional and global climate implications. Even though significant abundance of absorbing aerosols has been measured over the oceanic regions around India, studies addressing its spatial and vertical distributions and radiative impacts are sparse. Most of the regional-climate impacts assessments are mainly based on the Indian Ocean Experiment (INDOEX) data or using the chemical transport model simulations. In the backdrop of the regional climate implications of absorbing aerosols, exten-sive, spatially resolved measurements of aerosol microphysical properties were made onboard research ship and aircraft during the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) as a part of ISRO -Geosphere Biosphere Program. Aerosol parameters within the marine atmospheric boundary layer (MABL), free troposphere and in the entire column clearly depict large gradient along the latitudes and longitudes. Using these concurrent measurements of the aerosol properties, atmospheric radiative forcing and heating rates were estimated for a spatial resolution of 1 by 1. The spatial distribution of aerosol heating rate showed very high ( 0.5 K day per day) values over the northern Bay of Bengal and very low (¡ 0.1 K per day) values over the southeastern Arabian Sea. Similarly, aircraft measurements also showed an increase in the amplitude and strength of the elevated aerosol layers from south to north direction. Very high values of heating rate above the MABL modifies the thermody-namics structure of the atmosphere, which influence the stability of the lower troposphere and thus the hydrological cycle over the region. These gradients in atmospheric heating induced by aerosols will significantly influence the synoptic circulations over the regions when the winds are in transition from northeasterly to southwesterly

  20. Experiences from Occupational Exposure Limits Set on Aerosols Containing Allergenic Proteins

    PubMed Central

    Nielsen, Gunnar D.

    2012-01-01

    Occupational exposure limits (OELs) together with determined airborne exposures are used in risk assessment based managements of occupational exposures to prevent occupational diseases. In most countries, OELs have only been set for few protein-containing aerosols causing IgE-mediated allergies. They comprise aerosols of flour dust, grain dust, wood dust, natural rubber latex, and the subtilisins, which are proteolytic enzymes. These aerosols show dose-dependent effects and levels have been established, where nearly all workers may be exposed without adverse health effects, which are required for setting OELs. Our aim is to analyse prerequisites for setting OELs for the allergenic protein-containing aerosols. Opposite to the key effect of toxicological reactions, two thresholds, one for the sensitization phase and one for elicitation of IgE-mediated symptoms in sensitized individuals, are used in the OEL settings. For example, this was the case for flour dust, where OELs were based on dust levels due to linearity between flour dust and its allergen levels. The critical effects for flour and grain dust OELs were different, which indicates that conclusion by analogy (read-across) must be scientifically well founded. Except for subtilisins, no OEL have been set for other industrial enzymes, where many of which are high volume chemicals. For several of these, OELs have been proposed in the scientific literature during the last two decades. It is apparent that the scientific methodology is available for setting OELs for proteins and protein-containing aerosols where the critical effect is IgE sensitization and IgE-mediated airway diseases. PMID:22843406

  1. Experience with Aerosol Generation During Rotary Mode Core Sampling in the Hanford Single Shell Waste Tanks

    SciTech Connect

    SCHOFIELD, J.S.

    1999-08-31

    This document presents information on aerosol formation in tank head spaces during rotary mode core sampling (RMCS) from November 1994 through April 1999 in single shell waste tanks (SST) at the Hanford Site. The average tank head space mass concentration during RMCS has been 2.1E-5 g waste/m{sup 3}. The average mass of suspended solids present in a tank head space during RMCS has been 5.6E-2 g waste. The mass of waste sent to an exhauster during RMCS has averaged 5.3E-1 g waste per RMCS core and 8.3E-2 g waste per RMCS segment.

  2. Preliminary Experiments Using a Passive Detector for Measuring Indoor 220Rn Progeny Concentrations with an Aerosol Chamber.

    PubMed

    Sorimachi, Atsuyuki; Tokonami, Shinji; Kranrod, Chutima; Ishikawa, Tetsuo

    2015-06-01

    This paper describes preliminary experiments using a passive detector for integrating measurements of indoor thoron (²²⁰Rn) progeny concentrations with an aerosol chamber. A solid state nuclear detector (CR-39) covered with a thin aluminum-vaporized polyethylene plate (Mylar film) was used to detect only alpha particles emitted from ²¹²Po due to ²²⁰Rn progeny deposited on the detector surfaces. The initial experiment showed that Mylar film with area density of more than 5 mg cm⁻² was suitable to cut off completely alpha particles of 7.7 MeV from ²¹⁴Po of ²²²Rn progeny decay. In the experiment using the passive detector, it was observed that the net track density increased linearly with an increase of time-integrating ²²⁰Rn progeny concentration. As a result of dividing deposition rates by atom concentrations, the deposition velocity was given as 0.023 cm s⁻¹ for total ²²⁰Rn progeny. The model estimates of deposition velocities were 0.330 cm s⁻¹ for unattached ²²⁰Rn progeny and 0.0011 cm s⁻¹ for aerosol-attached ²²⁰Rn progeny using Lai-Nazaroff formulae. These deposition velocities were in the same range with the results reported in the literature. It was also found that the exposure experiments showed little influence of vertical profiles and surface orientations of the passive detector in the chamber on the detection responses, which was in good agreement with that in the model estimates. Furthermore, it was inferred that the main uncertainty of the passive detector was inhomogeneous deposition of Rn progeny onto its detection surfaces.

  3. Submicron Organic Aerosol Function Groups during the International Chemistry Experiment in the Arctic LOwer Troposphere (ICEALOT)

    NASA Astrophysics Data System (ADS)

    Russell, L. M.; Shaw, P. M.; Quinn, P. K.; Bates, T. S.

    2008-12-01

    Aerosol organic mass (OM) components are expected to have significant direct and indirect impacts on Arctic climate, especially during springtime Arctic haze. The chemical and physical properties of OM in Arctic aerosol remain largely unconstrained. The R/V Knorr traveled between Iceland and the Barents Sea during the ice-free months of March and April of 2008 and collected submicron particles on teflon filters for Fourier Transform Infrared (FTIR) spectroscopy to identify and quantify organic functional groups. Time series and composition are presented along with air mass back trajectories to indicate source regions. Early findings identify alcohols, alkanes, and carboxylic acids, with smaller amounts of amines, aromatics, alkenes and carbonyls. These data show the important contributions of organic oxygen and nitrogen in the Arctic region. Single particle analysis by Near-edge X-ray Absorption Fine Structure (NEXAFS) Scanning Transmission X- ray Microscopy (STXM) provides additional information about the distribution and morphology of the types of organic particles. Comparison to collocated simultaneous measurements by other techniques showed good agreement for OM and oxygenated organic fractions.

  4. Morphological characterization of soot aerosol particles during LACIS Experiment in November (LExNo)

    NASA Astrophysics Data System (ADS)

    Kiselev, A.; Wennrich, C.; Stratmann, F.; Wex, H.; Henning, S.; Mentel, T. F.; Kiendler-Scharr, A.; Schneider, J.; Walter, S.; Lieberwirth, I.

    2010-06-01

    Combined mobility and aerodynamic measurements were used to characterize the morphology of soot particles in an experimental campaign on the hygroscopic growth and activation of an artificial biomass burning aerosol. A custom-made, single-stage low-pressure impactor and two aerosol mass spectrometers (AMS) operating in the free molecular regime were used to measure the vacuum aerodynamic diameter of mobility-selected artificial soot particles that were produced in a spark discharge generator and then modified by condensation of ammonium hydrogen sulfate or levoglucosan as a coating to change their hydroscopic activity. Transmission electron microscope images revealed a relationship between the electrical mobility diameter and the diameter of the enveloping sphere, thus enabling evaluation of the effective density of soot agglomerates. A fractal description of the morphology of the soot aggregates allowed for evaluation of the average mass of the hygroscopic material per particle. The average mass of the hygroscopic material per particle was also measured directly with the two AMS instruments, and the agreement between the two methods was found satisfactory. This tandem approach allows detection of small changes in the particle effective density and morphology caused by condensation of organic material.

  5. Horizontal variability of aerosol optical depth observed during the ARCTAS airborne experiment

    NASA Astrophysics Data System (ADS)

    Shinozuka, Y.; Redemann, J.

    2011-08-01

    We present statistics on the horizontal variability of aerosol optical depth (AOD) directly measured from the NASA P-3 aircraft. Our measurements during two contrasting phases (in Alaska and Canada) of the ARCTAS mission arguably constrain the variability in most aerosol environments common over the globe. In the Canada phase, which features local emissions, 499 nm AOD has a median relative standard deviation (stdrel, med) of 19 % and 9 % and an autocorrelation (r) of 0.37 and 0.71 over 20 km and 6 km horizontal segments, respectively. In the Alaska phase, which features long-range transport, the variability is considerably lower (stdrel, med = 3 %, r = 0.92 even over 35.2 km). Compared to the magnitude of AOD, its wavelength dependence varies less in the Canada phase, more in the Alaska phase. We translate these findings from straight-line flight tracks into grid boxes and points, to help interpretation and design of satellite remote sensing, suborbital observations and transport modeling.

  6. Horizontal variability of aerosol optical depth observed during the ARCTAS airborne experiment

    NASA Astrophysics Data System (ADS)

    Shinozuka, Y.; Redemann, J.

    2011-05-01

    We present statistics on the horizontal variability of aerosol optical depth (AOD) directly measured from the NASA P-3 aircraft. Our measurements during two contrasting phases (in Alaska and Canada) of the ARCTAS mission arguably constrain the variability in most aerosol environments common over the globe. In the Canada phase, which features local emissions, 499 nm AOD has a median relative standard deviation (stdrel,med) of 19 % and 9 % and an autocorrelation (r) of 0.37 and 0.71 over 20 km and 6 km horizontal segments, respectively. In the Alaska phase, which features long-range transport, the variability is considerably lower (stdrel,med = 3 %, r = 0.92 even over 35.2 km). Compared to the magnitude of AOD, its wavelength dependence varies less in the Canada phase, more in the Alaska phase. We translate these findings from straight-line flight tracks into grid boxes and points, to help interpretation and design of satellite remote sensing, suborbital observations and transport modeling.

  7. Wavelength Dependence of the Absorption of Black Carbon Particles: Predictions and Results from the TARFOX Experiment and Implications for the Aerosol Single Scattering Albedo

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.; Russell, Philip B.; Hignett, Phillip

    2002-01-01

    Measurements are presented of the wavelength dependence of the aerosol absorption coefficient taken during the Tropical Aerosol Radiative Forcing Observational Experiment (TARFOX) over the northern Atlantic. The data show an approximate lamda(exp -1) variation between 0.40 and 1.0 micrometers. The theoretical basis of the wavelength variation of the absorption of solar radiation by elemental carbon [or black carbon (BC)] is explored. For a wavelength independent refractive index the small particle absorption limit simplifies to a lambda(exp -1) variation in relatively good agreement with the data. This result implies that the refractive indices of BC were relatively constant in this wavelength region, in agreement with much of the data on refractive indices of BC. However, the result does not indicate the magnitude of the refractive indices. The implications of the wavelength dependence of BC absorption for the spectral behavior of the aerosol single scattering albedo are discussed. It is shown that the single scattering albedo for a mixture of BC and nonabsorbing material decreases with wavelength in the solar spectrum (i.e., the percentage amount of absorption increases). This decease in the single scattering albedo with wavelength for black carbon mixtures is different from the increase in single scattering allied for most mineral aerosols (dusts). This indicates that, if generally true, the spectral variation of the single- scattering albedo can be used to distinguish aerosol types. It also highlights the importance of measurements of the spectral variation of the aerosol absorption coefficient and single scattering albedo.

  8. The technical basis for air pathway assessment of resuspended radioactive aerosols: LLNL experiences at seven sites around the world

    SciTech Connect

    Shinn, J.H.

    1993-09-01

    There is a large uncertainty in quantifying the inhalation pathway and the aerosol emission rate in human health assessments of radioactive-contamination sites. The need for site-specific assessments led to formation of our team of specialists at LLNL, who have participated in numerous field campaigns around the world. Our goal was to obtain all the information necessary for determining potential human exposures and to estimate source terms for turbulent transport of the emissions during both normal and disturbed soil conditions. That is, measurements were made of the key variables to quantify the suspended aerosols at the actual contamination sites, but different scenarios for habitation, site management, and site cleanup were included. The most notable locations of these site-investigations were the Marshall Islands (Bikini, Enewetak, and Rongelap), Nevada Test Site (GMX, Little Feller, Palanquin, and Plutonium Valley), Tonopah (Nevada--site of Roller Coaster), Savannah River Lab (South Carolina--H-Area site), Johnston Island (cleanup of rocket-impact site), Chernobyl (Ukraine--grass field end sandy beach sites near Nuclear Power Plant Unit 4), and Palomares (Spain--site of aircraft accident). This discussion will review the variables quantified, methods developed, general results, uncertainty of estimations, and recommendations for future research that are a result of our experience in these field studies.

  9. Constraining Aerosol Optical Models Using Ground-Based, Collocated Particle Size and Mass Measurements in Variable Air Mass Regimes During the 7-SEAS/Dongsha Experiment

    NASA Technical Reports Server (NTRS)

    Bell, Shaun W.; Hansell, Richard A.; Chow, Judith C.; Tsay, Si-Chee; Wang, Sheng-Hsiang; Ji, Qiang; Li, Can; Watson, John G.; Khlystov, Andrey

    2012-01-01

    During the spring of 2010, NASA Goddard's COMMIT ground-based mobile laboratory was stationed on Dongsha Island off the southwest coast of Taiwan, in preparation for the upcoming 2012 7-SEAS field campaign. The measurement period offered a unique opportunity for conducting detailed investigations of the optical properties of aerosols associated with different air mass regimes including background maritime and those contaminated by anthropogenic air pollution and mineral dust. What appears to be the first time for this region, a shortwave optical closure experiment for both scattering and absorption was attempted over a 12-day period during which aerosols exhibited the most change. Constraints to the optical model included combined SMPS and APS number concentration data for a continuum of fine and coarse-mode particle sizes up to PM2.5. We also take advantage of an IMPROVE chemical sampler to help constrain aerosol composition and mass partitioning of key elemental species including sea-salt, particulate organic matter, soil, non sea-salt sulphate, nitrate, and elemental carbon. Our results demonstrate that the observed aerosol scattering and absorption for these diverse air masses are reasonably captured by the model, where peak aerosol events and transitions between key aerosols types are evident. Signatures of heavy polluted aerosol composed mostly of ammonium and non sea-salt sulphate mixed with some dust with transitions to background sea-salt conditions are apparent in the absorption data, which is particularly reassuring owing to the large variability in the imaginary component of the refractive indices. Extinctive features at significantly smaller time scales than the one-day sample period of IMPROVE are more difficult to reproduce, as this requires further knowledge concerning the source apportionment of major chemical components in the model. Consistency between the measured and modeled optical parameters serves as an important link for advancing remote

  10. Origin of surface and columnar Indian Ocean Experiment (INDOEX) aerosols using source- and region-tagged emissions transport in a general circulation model - article no. D24211

    SciTech Connect

    Verma, S.; Venkataraman, C.; Boucher, O.

    2008-12-15

    We study the relative influence of aerosols emitted from different sectors and geographical regions on aerosol loading in south Asia. Sectors contributing aerosol emissions include biofuel and fossil fuel combustion, open biomass burning, and natural sources. Geographical regions include India, southeast Asia, east Asia, Africa-west Asia, and the rest of the world. Simulations of the Indian Ocean Experiment (INDOEX), from January to March 1999, are made in the general circulation model of Laboratoire de Meteorologie Dynamique (LMD-ZT GCM) with emissions tagged by sector and geographical region. Anthropogenic emissions dominate (54-88%) the predicted aerosol optical depth (AOD) over all the receptor regions. Among the anthropogenic sectors, fossil fuel combustion has the largest overall influence on aerosol loading, primarily sulfate, with emissions from India (50-80%) and rest of the world significantly influencing surface concentrations and AOD. Biofuel combustion has a significant influence on both the surface and columnar black carbon (BC) in particular over the Indian subcontinent and Bay of Bengal with emissions largely from the Indian region (60-80%). Open biomass burning emissions influence organic matter (OM) significantly, and arise largely from Africa-west Asia. The emissions from Africa-west Asia affect the carbonaceous aerosols AOD in all receptor regions, with their largest influence (AOD-BC: 60%; and AOD-OM: 70%) over the Arabian Sea. Among Indian regions, the Indo-Gangetic Plain is the largest contributor to anthropogenic surface mass concentrations and AOD over the Bay of Bengal and India. Dust aerosols are contributed mainly through the long-range transport from Africa-west Asia over the receptor regions. Overall, the model estimates significant intercontinental incursion of aerosol, for example, BC, OM, and dust from Africa-west Asia and sulfate from distant regions (rest of the world) into the INDOEX domain.

  11. Introduction and Overview of the AMazonian Aerosol characteriZation Experiment (AMAZE-08)

    NASA Astrophysics Data System (ADS)

    Martin, S. T.; Artaxo, P.; Team, A.

    2008-12-01

    The main objectives of AMAZE-08 were to understand the sources and regulators of organic particle mass in a pristine continental environment and the connections between particle chemistry and particle optical and hygroscopic properties. The AMAZE-08 tower measurements were conducted between February 7 and March 14, 2008 during the wet reason. The site was 60 km NNW of Manaus and located within a mostly pristine rainforest. The winds were predominantly from the ENE across 1600 km of mostly undeveloped forest. The site was mostly free of anthropogenic influences and allowed the study of pristine biological aerosol particles, although there were several episodes of long-range transport from Europe and Africa and more infrequent regional transport from Manaus and northerly biomass burning. Particle instrumentation included two high-resolution aerosol mass spectrometers (HR-ToF-AMS) with thermodenuder, two cloud condensation nuclei counters (CCNC), a continuous flow diffusion chamber (CFDC) for ice nuclei measurements, three optical particle counters (OPC), an ultraviolet aerodynamic particle sizer (UV-APS) for measurement of biologically active particles, two tapered element oscillating microbalances (TEOM), two scanning mobility particle sizers (SMPS), two multiwavelength nephelometers, three condensation particle counters (CPC), a multi-angle absorption photometer (MAAP), an athelometer, coarse- and fine-mode filters for elemental and ion analysis as well as particle imaging, an AERONET sun photometer including photosynthetically active radiation (PAR), and LIDAR system. Gas instrumentation included a proton-transfer mass spectrometer (PTR-MS), gas adsorption cartridge for off-line chromatographic analysis, and measurement of O3, CO, CO2, NO, and NOx. This talk will present an overview of AMAZE-08 and will highlight selected results.

  12. Airborne Lidar measurements of aerosols, mixed layer heights, and ozone during the 1980 PEPE/NEROS summer field experiment

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Shipley, S. T.; Butler, C. F.; Ismail, S.

    1985-01-01

    A detailed summary of the NASA Ultraviolet Differential Absorption Lidar (UV DIAL) data archive obtained during the EPA Persistent Elevated Pollution Episode/Northeast Regional Oxidant Study (PEPE/NEROS) Summer Field Experiment Program (July through August 1980) is presented. The UV dial data set consists of remote measurements of mixed layer heights, aerosol backscatter cross sections, and sequential ozone profiles taken during 14 long-range flights onboard the NASA Wallops Flight Center Electra aircraft. These data are presented in graphic and tabular form, and they have been submitted to the PEPE/NEROS data archive on digital magnetic tape. The derivation of mixing heights and ozone profiles from UV Dial signals is discussed, and detailed intercomparisons with measurements obtained by in situ sensors are presented.

  13. Note: A combined aerodynamic lens/ambient pressure x-ray photoelectron spectroscopy experiment for the on-stream investigation of aerosol surfaces

    SciTech Connect

    Mysak, Erin R.; Starr, David E.; Wilson, Kevin R.; Bluhm, Hendrik

    2010-01-15

    We discuss a new approach for the measurement of the surfaces of free aerosol particles with diameters from 50 to 1000 nm. Particles in this size range have significant influence on the heterogeneous chemistry in the atmosphere and affect human health. Interfacing an aerodynamic lens to an ambient pressure x-ray photoelectron spectrometer permits measurement of the surface chemical composition of unsupported aerosol particles in real time. We discuss the basic considerations for the design of such an instrument, its current limitations and potentials for improvement. Results from a proof-of-principle experiment on silicon oxide particles with average diameters of 270 nm are shown.

  14. Airborne LIDAR Measurements of Water Vapor, Ozone, Clouds, and Aerosols in the Tropics Near Central America During the TC4 Experiment

    NASA Technical Reports Server (NTRS)

    Kooi, Susan; Fenn, Marta; Ismail, Syed; Ferrare, Richard; Hair, John; Browell, Edward; Notari, Anthony; Butler, Carolyn; Burton, Sharon; Simpson, Steven

    2008-01-01

    Large scale distributions of ozone, water vapor, aerosols, and clouds were measured throughout the troposphere by two NASA Langley lidar systems on board the NASA DC-8 aircraft as part of the Tropical Composition, Cloud, and Climate Coupling Experiment (TC4) over Central and South America and adjacent oceans in the summer of 2007. Special emphasis was placed on the sampling of convective outflow and transport, sub-visible cirrus clouds, boundary layer aerosols, Saharan dust, volcanic emissions, and urban and biomass burning plumes. This paper presents preliminary results from this campaign, and demonstrates the value of coordinated measurements by the two lidar systems.

  15. ABOVE03, The 2003 AIRS BBAERI Ocean Validation Experiment: AIRS Validation and Aerosols

    NASA Astrophysics Data System (ADS)

    McMillan, W. W.; Hoff, R.; Strow, L. L.; Desouza-Machado, S.; Lightner, K.; McCourt, M. L.; Maddy, E.; Kolb, N.; McCann, K.; Comer, J.; Russo, F.; Rutledge, C. K.

    2003-12-01

    From May 28 to July 9, 2003, a complementary set of instruments was deployed to the United States Coast Guard (USCG) Chesapeake Light lighthouse platform to provide correlative measurements characterizing the atmosphere and sea surface over the ocean for validation of NASA's Atmospheric InfraRed Sounder (AIRS) onboard the Aqua satellite. Located 25 km due east of Virginia Beach, VA, Chesapeake Light offers a relatively convenient site for measurements over the ocean while being far enough offshore for water only AIRS fields of view. In addition to the UMBC Baltimore Bomem Atmospheric Emitted Radiance Interferometer (BBAERI), the UMBC Elastic Lidar Facility (ELF), and Vaisala RS-90 rawinsondes used during ABOVE02, we deployed in situ O3 and CO gas analyzers and during the first three weeks, flew 18 ozonesondes in collaboration with Dr. Mike Newchurch, UAH. A total of 140 Vaisala RS-90 radiosondes were launched covering 61 Aqua and 12 Terra overpasses. Preliminary comparisons of ABOVE03 data products to AIRS observations and retrievals will be presented. Particular attention will be paid to both AIRS and ground-based aerosol observations.

  16. Type-segregated aerosol effects on regional monsoon activity: A study using ground-based experiments and model simulations

    NASA Astrophysics Data System (ADS)

    Vijayakumar, K.; Devara, P. C. S.; Sonbawne, S. M.

    2014-12-01

    Classification of observed aerosols into key types [e.g., clean-maritime (CM), desert-dust (DD), urban-industrial/biomass-burning (UI/BB), black carbon (BC), organic carbon (OC) and mixed-type aerosols (MA)] would facilitate to infer aerosol sources, effects, and feedback mechanisms, not only to improve the accuracy of satellite retrievals but also to quantify the assessment of aerosol radiative impacts on climate. In this paper, we report the results of a study conducted in this direction, employing a Cimel Sun-sky radiometer at the Indian Institute of Tropical Meteorology (IITM), Pune, India during 2008 and 2009, which represent two successive contrasting monsoon years. The study provided an observational evidence to show that the local sources are subject to heavy loading of absorbing aerosols (dust and black carbon), with strong seasonality closely linked to the monsoon annual rainfall cycle over Pune, a tropical urban station in India. The results revealed the absence of CM aerosols in the pre-monsoon as well as in the monsoon seasons of 2009 as opposed to 2008. Higher loading of dust aerosols is observed in the pre-monsoon and monsoon seasons of 2009; majority may be coated with fine BC aerosols from local emissions, leading to reduction in regional rainfall. Further, significant decrease in coarse-mode AOD and presence of carbonaceous aerosols, affecting the aerosol-cloud interaction and monsoon-rain processes via microphysics and dynamics, is considered responsible for the reduction in rainfall during 2009. Additionally, we discuss how optical depth, contributed by different types of aerosols, influences the distribution of monsoon rainfall over an urban region using the Monitoring Atmospheric Composition and Climate (MACC) aerosol reanalysis. Furthermore, predictions of the Dust REgional Atmospheric Model (DREAM) simulations combined with HYSPLIT (HYbrid Single Particle Lagrangian Integrated Trajectory) cluster model are also discussed in support of the

  17. Intercomparison of elemental concentrations in total and size-fractionated aerosol samples collected during the mace head experiment, April 1991

    NASA Astrophysics Data System (ADS)

    François, Filip; Maenhaut, Willy; Colin, Jean-Louis; Losno, Remi; Schulz, Michael; Stahlschmidt, Thomas; Spokes, Lucinda; Jickells, Timothy

    During an intercomparison field experiment, organized at the Atlantic coast station of Mace Head, Ireland, in April 1991, aerosol samples were collected by four research groups. A variety of samplers was used, combining both high- and low-volume devices, with different types of collection substrates: Hi-Vol Whatman 41 filter holders, single Nuclepore filters and stacked filter units, as well as PIXE cascade impactors. The samples were analyzed by each participating group, using in-house analytical techniques and procedures. The intercomparison of the daily concentrations for 15 elements, measured by two or more participants, revealed a good agreement for the low-volume samplers for the majority of the elements, but also indicated some specific analytical problems, owing to the very low concentrations of the non-sea-salt elements at the sampling site. With the Hi-Vol Whatman 41 filter sampler, on the other hand, much higher results were obtained in particular for the sea-salt and crustal elements. The discrepancy was dependent upon the wind speed and was attributed to a higher collection efficiency of the Hi-Vol sampler for the very coarse particles, as compared to the low-volume devices under high wind speed conditions. The elemental mass size distribution, as derived from parallel cascade impactor samplings by two groups, showed discrepancies in the submicrometer aerosol fraction, which were tentatively attributed to differences in stage cut-off diameters and/or to bounce-off or splintering effects on the quartz impactor slides used by one of the groups. However, the atmospheric concentrations (sums over all stages) were rather similar in the parallel impactor samples and were only slightly lower than those derived from stacked filter unit samples taken in parallel.

  18. Overview of the Stratospheric Aerosol and Gas Experiment II water vapor observations: Method, validation, and data characteristics

    SciTech Connect

    Rind, D. ); Chiou, E.W.; Larsen, J. ); Chu, W.; McCormick, M.P.; McMaster, L. ); Oltmans, S. ); Lerner, J. )

    1993-03-20

    Water vapor observations obtained from the Stratospheric Aerosol and Gas Experiment II (SAGE II) solar occulation instrument for the troposphere and stratosphere are presented and compared with correlative in situ measurement techniques and other satellite data. The SAGE II instrument produces water vapor values from cloud top to approximately 1 mbar, except in regions of high aerosol content such as occurs in the low to middle stratosphere after volcanic eruptions. Details of the analysis procedure, instrumental errors, and data characteristics are discussed. Various features of the data set for the first 5 years after launch (1985-1989) are identified. These include an increase in middle and upper tropospheric water vapor during northern hemisphere summer and autumn, thus at times of warmest sea surface temperature; minimum water vapor values of 2.5-3 ppmv in the tropical lower stratosphere, with lower values during northern hemisphere winter and spring; slowly increasing water vapor values with altitude in the stratosphere, reaching 5-6 ppmv or greater near the stratopause; extratropical values with minimum profile amounts occurring above the conventionally defined tropopause; and higher extratropical than tropical water vapor values throughout the stratosphere except in locations of possible polar stratospheric clouds. SAGE II data will be useful for studying individual water vapor profiles, tropospheric response to climate perturbations, tropospheric-stratospheric exchange (due to its inherent high vertical resolution), and stratospheric transports. It should also aid in the preparation, for the first time on a global scale, of climatologies of the stratosphere and the upper level cloud-free troposphere, for use in radiative, dynamical, and chemical studies. 57 refs., 6 figs., 5 tabs.

  19. Radiative Effects of Aerosols

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.

    1997-01-01

    During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in aerosol optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size resolved aerosol microphysics and chemistry. Both profiles included pollution haze layer from Europe but the second also included the effect of a Saharan dust layer above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) aerosol were determined and thermal analysis of the pollution haze indicated that the fine aerosol was composed primarily of a sulfate/water mixture with a refractory soot-like core.

  20. Absence of Detectable Influenza RNA Transmitted via Aerosol during Various Human Respiratory Activities – Experiments from Singapore and Hong Kong

    PubMed Central

    Cowling, Benjamin J.; Koh, Gerald C.; Chu, Daniel; Heilbronn, Cherie; Lloyd, Belinda; Pantelic, Jovan; Nicolle, Andre D.; Klettner, Christian A.; Peiris, J. S. Malik; Sekhar, Chandra; Cheong, David K. W.; Tham, Kwok Wai; Koay, Evelyn S. C.; Tsui, Wendy; Kwong, Alfred; Chan, Kitty; Li, Yuguo

    2014-01-01

    Two independent studies by two separate research teams (from Hong Kong and Singapore) failed to detect any influenza RNA landing on, or inhaled by, a life-like, human manikin target, after exposure to naturally influenza-infected volunteers. For the Hong Kong experiments, 9 influenza-infected volunteers were recruited to breathe, talk/count and cough, from 0.1 m and 0.5 m distance, onto a mouth-breathing manikin. Aerosolised droplets exhaled from the volunteers and entering the manikin’s mouth were collected with PTFE filters and an aerosol sampler, in separate experiments. Virus detection was performed using an in-house influenza RNA reverse-transcription polymerase chain reaction (RT-PCR) assay. No influenza RNA was detected from any of the PTFE filters or air samples. For the Singapore experiments, 6 influenza-infected volunteers were asked to breathe (nasal/mouth breathing), talk (counting in English/second language), cough (from 1 m/0.1 m away) and laugh, onto a thermal, breathing manikin. The manikin’s face was swabbed at specific points (around both eyes, the nostrils and the mouth) before and after exposure to each of these respiratory activities, and was cleaned between each activity with medical grade alcohol swabs. Shadowgraph imaging was used to record the generation of these respiratory aerosols from the infected volunteers and their impact onto the target manikin. No influenza RNA was detected from any of these swabs with either team’s in-house diagnostic influenza assays. All the influenza-infected volunteers had diagnostic swabs taken at recruitment that confirmed influenza (A/H1, A/H3 or B) infection with high viral loads, ranging from 105-108 copies/mL (Hong Kong volunteers/assay) and 104–107 copies/mL influenza viral RNA (Singapore volunteers/assay). These findings suggest that influenza RNA may not be readily transmitted from naturally-infected human source to susceptible recipients via these natural respiratory activities, within these

  1. Absence of detectable influenza RNA transmitted via aerosol during various human respiratory activities--experiments from Singapore and Hong Kong.

    PubMed

    Tang, Julian W; Gao, Caroline X; Cowling, Benjamin J; Koh, Gerald C; Chu, Daniel; Heilbronn, Cherie; Lloyd, Belinda; Pantelic, Jovan; Nicolle, Andre D; Klettner, Christian A; Peiris, J S Malik; Sekhar, Chandra; Cheong, David K W; Tham, Kwok Wai; Koay, Evelyn S C; Tsui, Wendy; Kwong, Alfred; Chan, Kitty; Li, Yuguo

    2014-01-01

    Two independent studies by two separate research teams (from Hong Kong and Singapore) failed to detect any influenza RNA landing on, or inhaled by, a life-like, human manikin target, after exposure to naturally influenza-infected volunteers. For the Hong Kong experiments, 9 influenza-infected volunteers were recruited to breathe, talk/count and cough, from 0.1 m and 0.5 m distance, onto a mouth-breathing manikin. Aerosolised droplets exhaled from the volunteers and entering the manikin's mouth were collected with PTFE filters and an aerosol sampler, in separate experiments. Virus detection was performed using an in-house influenza RNA reverse-transcription polymerase chain reaction (RT-PCR) assay. No influenza RNA was detected from any of the PTFE filters or air samples. For the Singapore experiments, 6 influenza-infected volunteers were asked to breathe (nasal/mouth breathing), talk (counting in English/second language), cough (from 1 m/0.1 m away) and laugh, onto a thermal, breathing manikin. The manikin's face was swabbed at specific points (around both eyes, the nostrils and the mouth) before and after exposure to each of these respiratory activities, and was cleaned between each activity with medical grade alcohol swabs. Shadowgraph imaging was used to record the generation of these respiratory aerosols from the infected volunteers and their impact onto the target manikin. No influenza RNA was detected from any of these swabs with either team's in-house diagnostic influenza assays. All the influenza-infected volunteers had diagnostic swabs taken at recruitment that confirmed influenza (A/H1, A/H3 or B) infection with high viral loads, ranging from 10(5)-10(8) copies/mL (Hong Kong volunteers/assay) and 10(4)-10(7) copies/mL influenza viral RNA (Singapore volunteers/assay). These findings suggest that influenza RNA may not be readily transmitted from naturally-infected human source to susceptible recipients via these natural respiratory activities, within these

  2. Direct Observation of Secondary Organic Aerosol Formation during Cloud Condensation-Evaporation Cycles (SOAaq) in Simulation Chamber Experiments

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Biogenic volatile organic compounds (BVOCs) undergo many reactions in the atmosphere and form a wide range of oxidised and water-soluble compounds. These compounds can partition into atmospheric water droplets, and react within the aqueous phase producing higher molecular weight and/or less volatile compounds which can remain in the particle phase after water evaporation and thus increase the organic aerosol mass (Ervens et al., 2011; Altieri et al., 2008; Couvidat et al., 2013). While this hypothesis is frequently discussed in the literature, so far, almost no direct observations of such a process have been provided.The aim of the present work is to study SOA formation from isoprene photooxidation during cloud condensation-evaporation cycles.The experiments were performed during the CUMULUS project (CloUd MULtiphase chemistry of organic compoUndS in the troposphere), in the CESAM simulation chamber located at LISA. CESAM is a 4.2 m3 stainless steel chamber equipped with realistic irradiation sources and temperature and relative humidity (RH) controls (Wang et al., 2011). In each experiment, isoprene was allowed to oxidize during several hours in the presence on nitrogen oxides under dry conditions. Gas phase compounds were analyzed on-line by a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToF-MS), a Fourier Transform Infrared Spectrometer (FTIR), NOx and O3 analyzers. SOA formation was monitored on-line with a Scanning Mobility Particle Sizer (SMPS) and an Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). The experimental protocol was optimised to generate cloud events in the simulation chamber, which allowed us to generate clouds lasting for ca. 10 minutes in the presence of light.In all experiments, we observed that during cloud formation, water-soluble gas-phase oxidation products (e.g., methylglyoxal, hydroxyacetone, acetaldehyde, formic acid, acetic acid and glycolaldehyde) readily partitioned into cloud

  3. Size distribution, composition and origin of the submicron aerosol in the marine boundary layer during the eastern Mediterranean "SUB-AERO" experiment

    NASA Astrophysics Data System (ADS)

    Eleftheriadis, K.; Colbeck, I.; Housiadas, C.; Lazaridis, M.; Mihalopoulos, N.; Mitsakou, C.; Smolík, J.; Ždímal, V.

    A period of intensive physical and chemical aerosol characterisation measurements was held over 5 days during July 2000 as part of the European SUB-AERO experiment.. Concurrent measurements were performed at the Finokalia remote coastal site on the island of Crete (Greece) and onboard the R/V " Aegaeon" which cruised in south part of the Aegean Sea northwards of Crete. The objective of the study was to investigate the spatial and temporal variability of microphysical parameters of the submicron aerosol and their dependence on airmass origin and chemical composition. The results reflect the submicron aerosol properties during airmass transport from the north including Europe and the Balkans and are in line with other studies on the aerosol properties of polluted continental air entering the marine boundary layer (MBL). Concentrations of submicron particulate matter (PM) mass were relatively higher at sea (20 μg m -3) compared to the coastal site (16 μg m -3). Concentrations of both organic carbon and sulphate, being the major water soluble component, were also higher at sea than at land. The high concentrations of ammonium and those of the water soluble organics, such as oxalate, can be attributed to emissions from mainland forest fires. The submicron aerosol number size distribution was unimodal with mobility mean diameters ( dg) ranging from 98 to 144 μm and standard deviations ( σg) from 1.56 to 1.9. Aerosol number concentrations at Finokalia were at least 50% lower especially when R/V Aegaeon sampled polluted air, but the modal parameters of the size distribution were very similar ( dg: 111-120, σg: 1.55-1.91). The surface MBL, under these conditions, was an aerosol rich environment where aerosol particles were transported both by the surface wind, advected from higher layers, chemically processed by interactions with gaseous precursors and physically altered by water vapour. The number to volume ratio for the submicrometer aerosol fraction reflected the

  4. SAGE II aerosol data validation based on retrieved aerosol model size distribution from SAGE II aerosol measurements

    NASA Technical Reports Server (NTRS)

    Wang, Pi-Huan; Mccormick, M. P.; Mcmaster, L. R.; Chu, W. P.; Swissler, T. J.; Osborn, M. T.; Russell, P. B.; Oberbeck, V. R.; Livingston, J.; Rosen, J. M.

    1989-01-01

    Consideration is given to aerosol correlative measurements experiments for the Stratospheric Aerosol and Gas Experiment (SAGE) II, conducted between November 1984 and July 1986. The correlative measurements were taken with an impactor/laser probe, a dustsonde, and an airborne 36-cm lidar system. The primary aerosol quantities measured by the ground-based instruments are compared with those calculated from the aerosol size distributions from SAGE II aerosol extinction measurements. Good agreement is found between the two sets of measurements.

  5. An Investigation of Aerosol Measurements from the Halogen Occultation Experiment: Validation, Size Distributions, Composition, and Relation to Other Chemical Species

    NASA Technical Reports Server (NTRS)

    Deshler, Terry; Hervig, Mark E.

    1998-01-01

    The efforts envisioned within the original proposal (accepted February 1994) and the extension of this proposal (accepted February 1997) included measurement validations, the retrieval of aerosol size distributions and distribution moments, aerosol correction studies, and investigations of polar stratospheric clouds. A majority of the results from this grant have been published. The principal results from this grant are discussed.

  6. The COSmIC/THS experiment: gas and solid phase studies of Titan aerosol simulants produced at cold temperature

    NASA Astrophysics Data System (ADS)

    Sciamma-OBrien, E. M.; Upton, K.; Beauchamp, J. L.; Salama, F.

    2013-12-01

    In Titan's atmosphere, a complex chemistry between N2 and CH4 occurs at temperatures lower than 200K and leads to the production of heavy molecules and subsequently solid aerosols that form the haze surrounding Titan. The Titan Haze Simulation (THS) experiment has been developed at the NASA Ames COSmIC facility to study Titan's atmospheric chemistry at low temperature, and in particular to study the chemical pathways that link the simple molecules resulting from the first steps of the N2-CH4 chemistry to benzene, and to PAHs and nitrogen-containing PAHs (PANHs), potential precursors to Titan's solid aerosols. In the COSmIC/THS, the chemistry is simulated by plasma in the stream of a supersonic expansion. With this unique design, the gas is jet-cooled to Titan-like temperature (~150K) before inducing the chemistry by plasma, and remains at low temperature in the plasma discharge (~200K measured by optical emission spectroscopy). Different N2-CH4-based gas mixtures can be injected in the plasma, with or without the addition of trace elements present on Titan. Both the gas phase and solid phase products resulting from the plasma-induced chemistry can be monitored and analyzed using a combination of complementary in situ and ex situ diagnostics: Cavity Ring Down Spectroscopy and Time-Of-Flight Mass Spectrometry (TOF-MS) for the gas phase; Direct Analysis in Real Time Mass Spectrometry (DART-MS), Gas Chromatography-Mass Spectrometry (GC-MS), Scanning Electron Microscopy (SEM), Raman spectroscopy, Nuclear Magnetic Resonance (NMR) and Infrared (IR) spectroscopy for the solid phase. Previous TOF-MS mass spectrometry analyses of the gas phase have demonstrated that the COSmIC/THS experiment can be used to study the first and intermediate steps as well as specific chemical pathways of Titan's atmospheric chemistry. The more complex chemistry, observed in the gas phase when adding trace elements to the initial N2-CH4 mixture, has been confirmed by an extensive study of the

  7. Photophoretic manipulation of absorbing aerosol particles with vortex beams: theory versus experiment.

    PubMed

    Desyatnikov, Anton S; Shvedov, Vladlen G; Rode, Andrei V; Krolikowski, Wieslaw; Kivshar, Yuri S

    2009-05-11

    We develop a theoretical approach for describing the optical trapping and manipulation of carbon nanoclusters in air with a dual-vortex optical trap, as realized recently in experiment [V. Shvedov et al., Opt. Express 17, 5743 (2009)]. We calculate both longitudinal and transverse photophoretic forces acting on a spherical absorbing particle, and then compare our theoretical predictions with the experimental data. PMID:19434152

  8. East Asian Study of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE): Preliminary Results from 2005

    NASA Astrophysics Data System (ADS)

    Dickerson, R. R.; Li, C.; Li, Z.; Marufu, L. T.; Stehr, J.; Chen, H.; Wang, P.; Wang, Y.; Wen, T.; Xia, X.

    2005-12-01

    In order to gain a basic knowledge of the characteristics of aerosols and gases and an understanding of their climatic effects, a team of scientists from the U.S. and China conducted major field campaigns on the ground and from the air in the spring of 2005, and in addition established long-term and nation-wide observation facilities. Research flights on a small, instrumented aircraft investigated the role of meteorology in lofting pollutants and mineral dust and in large-scale impacts. Ahead of fronts, transport along warm conveyor belts and in convection, often dry convection, lifted trace gases and aerosols to altitudes where stronger winds and longer lifetimes transform these pollutants from local air quality problems to hemispheric atmospheric chemistry problems. Air behind cold fronts often contained high concentrations of mineral dust at altitudes of 3000 m or higher. At the central station in Xianghe (70 km east of Beijing), extensive measurements are made including 1) radiative quantities (direct, diffuse and total SW and LW fluxes) using broadband and narrow radiometers, and spectrometers; 2) cloud properties (cloud fraction and height, optical depth, liquid water path, particle size); 3) aerosol optical quantities (optical depth, scattering and absorbing coefficients, vertical attenuation profiles) using Cimel sun-photometer, Nephelometer, Aethalometers, PSAP; 4) aerosol physical quantities (size distribution, mass and condensation number) using aerosol filter samplers, cascade impactors, particle sizers; 5) aerosol compositions using OC/EC analyzer, aerosol filters and sample analyzers, 6) trace gases O3, NO, NOx, NOy, CO, SO2.

  9. Annual variations of water vapor in the stratosphere and upper troposphere observed by the Stratospheric Aerosol and Gas Experiment II

    SciTech Connect

    McCormick, M.P.; McMaster, L.R.; Chu, W.P. ); Chiou, E.W.; Larsen, J.C. ); Rind, D. ); Oltmans, S. )

    1993-03-20

    This paper presents a description of the annual variations of water vapor in the stratosphere and the upper troposphere derived from observations of the Stratospheric Aerosol and Gas Experiment II (SAGE II). The altitude-time cross sections exhibit annually repeatable patterns in both hemispheres. The appearance of a yearly minimum in water vapor in both hemispheres at approximately the same time supports the idea of a common source(s) for stratospheric dry air. Annual patterns observed at northern mid-latitudes, like the appearance of a hygropause in winter and the weakening and upward shifting of the hygropause from January to May, agree with in situ balloon observations previously obtained over Boulder and Washington, DC. An increase in water vapor with altitude in the tropics is consistent with methane oxidation in the upper stratosphere to lower mesosphere as a source for water vapor. A poleward gradient is also shown as expected based on a Lagrangian mean circulation. A linear regression analysis using SAGE II data from January 1986 to December 1988 shows that little annual variation occurs in the middle and upper stratosphere with the region of large annual variability near the tropopause. The semi-annual variability is relatively marked at altitudes of 24 and 40 km in the tropics. 30 refs., 4 figs., 1 tab.

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

    NASA Technical Reports Server (NTRS)

    Bonine, Lauren

    2015-01-01

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

  11. Intercomparison of stratospheric water vapor observed by satellite experiments: Stratospheric Aerosol and Gas Experiment II versus Limb Infrared Monitor of the Stratosphere and Atmospheric Trace Molecule Spectroscopy

    SciTech Connect

    Chiou, E.W.; Larsen, J.C. ); McCormick, M.P.; McMaster, L.R.; Chu, W.P. ); Rind, D. ); Oltmans, S. )

    1993-03-20

    This paper presents a comparison of the stratospheric water vapor measurements made by the satellite-borne sensors the Stratospheric Aerosol and Gas Experiment II (SAGE II), the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS), and the Spacelab 3 Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment. LIMS obtained data for 7 months between November 1978 and May 1979; ATMOS was carried on Shuttle and observed eight profiles from April 30 to May 6, 1985 at approximately 30[degrees]N and 50[degrees]S; and, SAGE II continues to make measurements since its launch in October 1984. For both 30[degrees]N and 50[degrees]S in May, the comparisons between SAGE II and ATMOS show agreement within the estimated combined uncertainty of the two experiments. Several important features identified by LIMS observations have been confirmed by SAGE II: a well-developed hygropause in the lower stratosphere at low- to mid-latitudes, a poleward latitudinal gradient, increasing water vapor mixing ratios with altitude in the tropics, and the transport of dry lower stratospheric water vapor upward and southward in May, and upward and northward in November. A detailed comparative study also indicates that the two previously suggested corrections for LIMS, a correction in tropical lower stratosphere due to a positive temperature bias and the correction above 28 km based on improved emissivities will bring LIMS measurements much closer to those of SAGE II. The only significant difference occurs at high southern latitudes in May below 18 km, where LIMS measurements are 2-3 ppmv greater. It should be noted that LIMS observations are from 16 to 50 km, ATMOS from 14 to 86 km, and SAGE II from mid-troposphere to 40 km. With multiyear coverage, SAGE II observations should be useful for studying tropospheric-stratospheric exchange, for stratospheric transport, and for preparing water vapor climatologies for the stratosphere and the upper troposphere. 32 refs., 14 figs., 2 tabs.

  12. Quantitative Laboratory Experiments on Contact Freezing and Secondary Ice Production induced by Aerosol- Cloud Droplet Collisions

    NASA Astrophysics Data System (ADS)

    Leisner, T.; Kiselev, A. A.; Hoffmann, N.; Pander, T.; Handmann, P.

    2014-12-01

    We report on laboratory experiments on contact freezing probabilities and secondary ice processes accompanying the contact- or immersion freezing of cloud droplets. The freezing of individual, electrodynamically levitated cloud droplets was initiated by contacting them with ice nuclei or by immersed ice nuclei. The freezing process itself and secondary ice formation by either splintering of the freezing droplet or the ejection of gas bubble membranes has been observed and analyzed by high speed light microscopy. In our contribution, we classify these processes and quantify their temperature dependent probability as a function of the mode of freezing and the presence of immersed particles. Contact freezing probabilities have been calculated from the measured freezing rates and contact rates, the latter being determined offline by counting the number of scavenged particles under and environmental scanning electron microscope.

  13. On the relationship between aerosol content and errors in telephotometer experiments.

    NASA Technical Reports Server (NTRS)

    Thomas, R. W. L.

    1971-01-01

    This paper presents an invariant imbedding theory of multiple scattering phenomena contributing to errors in telephotometer experiments. The theory indicates that there is a simple relationship between the magnitudes of the errors introduced by successive orders of scattering and it is shown that for all optical thicknesses each order can be represented by a coefficient which depends on the field of view of the telescope and the properties of the scattering medium. The verification of the theory and the derivation of the coefficients have been accomplished by a Monte Carlo program. Both monodisperse and polydisperse systems of Mie scatterers have been treated. The results demonstrate that for a given optical thickness the coefficients increase strongly with the mean particle size particularly for the smaller fields of view.

  14. Numerical simulations of the July 10 Stratospheric-Tropospheric Experiment: Radiation, Aerosols, and Ozone/Deep Convection Experiment convective system: Kinematics and transport

    NASA Astrophysics Data System (ADS)

    Skamarock, William C.; Powers, Jordan G.; Barth, Mary; Dye, James E.; Matejka, Thomas; Bartels, Diana; Baumann, Karsten; Stith, Jeffrey; Parrish, David D.; Hubler, Gerhard

    2000-08-01

    The observed July 10, 1996, Stratospheric-Tropospheric Experiment: Radiation, Aerosols, and Ozone (STERAO) convective system is broadly reproduced in a nonhydrostatic cloud model simulation using an idealized horizontally homogeneous sounding and no terrain. System evolution from a multicellular line to a supercell, along with line orientation, anvil structure, horizontal wind fields, depth of convection, and derived radar reflectivity, compares well with observations. Simulated passive tracer transport of CO and ozone generally agrees with aircraft measurements and shows a small amount of entrainment of environmental air in the updrafts, and a small amount of dilution occurring with transport downwind in the anvil; the entrainment and dilution are less pronounced in the supercell stage. The horizontally integrated vertical flux divergence for CO in the simulation shows a net gain at almost all levels above 8 km mean sea level (msl). The rate of increase of CO mass above 8 km varies significantly in time, with a peak at early times, followed by a decline and minimum as the system transitions to a supercell and a steady increase as the supercell matures. Trajectory analyses show that updrafts in the simulation are ingesting air from a layer spanning from 2 km to 3.5 km msl (from 0.5 to 2km above the surface). The residence times for parcels in the updraft varies from just under 10 min to more than 20 min, with most parcels taking approximately 10 min to ascend to the anvil.

  15. In situ measurements of trace gases and aerosol optical properties at a rural site in northern China during East Asian Study of Tropospheric Aerosols: An International Regional Experiment 2005

    NASA Astrophysics Data System (ADS)

    Li, Can; Marufu, Lackson T.; Dickerson, Russell R.; Li, Zhanqing; Wen, Tianxue; Wang, Yuesi; Wang, Pucai; Chen, Hongbin; Stehr, Jeffrey W.

    2007-11-01

    In situ measurements of trace gases and aerosol optical properties were made in March 2005 at Xianghe (39.798°N, 116.958°E, 35 m), a rural site about 70 km southeast, and generally downwind of the Beijing metropolitan area. High pollutant levels were observed during the experiment, with CO (1.09 ± 1.02 ppmv, average ± standard deviation), SO2 (17.8 ± 15.7 ppbv), NOy (26.0 ± 24.0 ppbv), aerosol scattering coefficients (bsp, (468 ± 472) × 10-6 m-1), and aerosol absorption coefficients (bap, (65 ± 75) × 10-6 m-1) all much higher than observed at some rural sites in the United States. O3 (29.1 ± 16.5 ppbv) was relatively low during this study, suggesting inactive photochemical processes. Strong synoptic fluctuations in pollutant levels were detected every 4-5 days during the experiment, as cold fronts passing over the region drastically reduced the ground-level pollution. Very little precipitation was measured during the whole observational period, implying pollutant uplift and transport by rain-free cold fronts and dry convection. The single scattering albedo (SSA) observed (0.81 in the morning and 0.85 in the afternoon) indicates strongly absorbing aerosols near surface. The observed CO/SO2 ratio (35.8) is higher than inventory values, but closer to the updated CO inventory of Streets et al. (2006) than to Streets et al. (2003) or Wang et al. (2005). The observed CO/NOy ratio agrees better with inventories. Further analysis suggests that such comparisons may shed some light on the quality of emission inventories, but quantification of any error requires more extensive measurements over longer period and larger areas, as well as direct characterization of emission sources, especially mobile sources and small boilers. Using black carbon (BC)/CO ratio from the experiment, BC emissions from China are estimated at about 1300 Gg (109 g)/yr, but could be as high as 2600 Gg/yr.

  16. Impact of aftertreatment devices on primary emissions and secondary organic aerosol formation potential from in-use diesel vehicles: results from smog chamber experiments

    NASA Astrophysics Data System (ADS)

    Chirico, R.; Decarlo, P. F.; Heringa, M. F.; Tritscher, T.; Richter, R.; Prévôt, A. S. H.; Dommen, J.; Weingartner, E.; Wehrle, G.; Gysel, M.; Laborde, M.; Baltensperger, U.

    2010-12-01

    Diesel particulate matter (DPM) is a significant source of aerosol in urban areas and has been linked to adverse health effects. Although newer European directives have introduced increasingly stringent standards for primary PM emissions, gaseous organics emitted from diesel cars can still lead to large amounts of secondary organic aerosol (SOA) in the atmosphere. Here we present results from smog chamber investigations characterizing the primary organic aerosol (POA) and the corresponding SOA formation at atmospherically relevant concentrations for three in-use diesel vehicles with different exhaust aftertreatment systems. One vehicle lacked exhaust aftertreatment devices, one vehicle was equipped with a diesel oxidation catalyst (DOC) and the third vehicle used both a DOC and diesel particulate filter (DPF). The experiments presented here were obtained from the vehicles at conditions representative of idle mode, and for one car in addition at a speed of 60 km/h. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was used to measure the organic aerosol (OA) concentration and to obtain information on the chemical composition. For the conditions explored in this paper, primary aerosols from vehicles without a particulate filter consisted mainly of black carbon (BC) with a low fraction of organic matter (OM, OM/BC < 0.5), while the subsequent aging by photooxidation resulted in a consistent production of SOA only for the vehicles without a DOC and with a deactivated DOC. After 5 h of aging ~80% of the total organic aerosol was on average secondary and the estimated "emission factor" for SOA was 0.23-0.56 g/kg fuel burned. In presence of both a DOC and a DPF, only 0.01 g SOA per kg fuel burned was produced within 5 h after lights on. The mass spectra indicate that POA was mostly a non-oxidized OA with an oxygen to carbon atomic ratio (O/C) ranging from 0.10 to 0.19. Five hours of oxidation led to a more oxidized OA with an O/C range of 0

  17. Impact of aftertreatment devices on primary emissions and secondary organic aerosol formation potential from in-use diesel vehicles: results from smog chamber experiments

    NASA Astrophysics Data System (ADS)

    Chirico, R.; Decarlo, P. F.; Heringa, M. F.; Tritscher, T.; Richter, R.; Prevot, A. S. H.; Dommen, J.; Weingartner, E.; Wehrle, G.; Gysel, M.; Laborde, M.; Baltensperger, U.

    2010-06-01

    Diesel particulate matter (DPM) is a significant source of aerosol in urban areas and has been linked to adverse health effects. Although newer European directives have introduced increasingly stringent standards for primary PM emissions, gaseous organics emitted from diesel cars can still lead to large amounts of secondary organic aerosol (SOA) in the atmosphere. Here we present results from smog chamber investigations characterizing the primary organic aerosol (POA) and the corresponding SOA formation at atmospherically relevant concentrations for three in-use diesel vehicles with different exhaust aftertreatment systems. One vehicle lacked exhaust aftertreatment devices, one vehicle was equipped with a diesel oxidation catalyst (DOC) and the final vehicle used both a DOC and diesel particulate filter (DPF). The experiments presented here were obtained from the vehicles at conditions representative of idle mode, and for one car in addition at a speed of 60 km/h. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was used to measure the organic aerosol (OA) concentration and to obtain information on the chemical composition. For the conditions explored in this paper, primary aerosols from vehicles without a particulate filter consisted mainly of black carbon (BC) with a low fraction of organic matter (OM, OM/BC<0.5), while the subsequent aging by photooxidation resulted in a consistent production of SOA only for the vehicles without a DOC and with a deactivated DOC. After 5 h of aging ~80% of the total organic aerosol was on average secondary and the estimated "emission factor" for SOA was 0.23-0.56 g/kg fuel burned. In presence of both a DOC and a DPF, primary particles with a mobility diameter above 5 nm were 300±19 cm-3, and only 0.01 g SOA per kg fuel burned was produced within 5 h after lights on. The mass spectra indicate that POA was mostly a non-oxidized OA with an oxygen to carbon atomic ratio (O/C) ranging from 0.097 to 0

  18. AEROSOL INDUSTRY SUCCESS IN REDUCING CFC PROPELLANT USAGE

    EPA Science Inventory

    Part I of this report discusses the U.S. aerosol industry's experience in converting from chlorofluorocarbon (CFC) propellants to alternative aerosol formulations. Detailed examples of non-CFC formulations are provided for 28 categories of aerosol products. ydrocarbon propellants...

  19. The Charged Aerosol Release Experiment (Care II) to Study Artificial Dusty Plasmas in the Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Bernhardt, P. A.; Siefring, C. L.; Gatling, G.; Briczinski, S. J., Jr.; Vierinen, J.; Bhatt, A.; Holzworth, R. H., II; McCarthy, M.; Gustavsson, B.; La Hoz, C.; Latteck, R.

    2015-12-01

    A sounding rocket launched from Andoya, Norway in September 2015 carried 37 rocket motors and a multi-instrument daughter payload into the ionosphere to study the generation of plasma wave electric fields and ionospheric density disturbances by the high-speed injection of dust particles. The primary purpose of the CARE II mission is to validate the dress-particle theory of enhanced incoherent scatter from a dusty plasma and to validate models of plasma instabilities driven by high-speed charged particles. The CARE II chemical payload produces 66 kg of micron-sized dust particles composed of aluminium oxide. In addition to the dust, simple molecular combustion products such as N2, H2, CO2, CO, H20 and NO will be injected into the bottomside of the F-layer. Charging of the dust and ion charge exchange with the molecules yields plasma particles moving at hypersonic velocities. Streaming instabilities and shear electric fields causes plasma turbulence that can be detected using ground radars and in situ plasma instruments. The instrument payload was separated from the chemical release payload soon after launch to measure electric field vectors, electron and ion densities, and integrated electron densities from the rocket to the ground. The chemical release of high speed dust was directed upward on the downleg of the rocket trajectory to intersect the F-Layer. The instrument section was about 600 meters from the dust injection module at the release time. Ground HF and UHF radars were operated to detected scatter and refraction by the modified ionosphere. Optical instruments from airborne and ground observatories were used to map the dispersal of the dust using scattered sunlight. The plasma interactions are being simulated with both fluid and particle-in-cell (PIC) codes. CARE II is a follow-on to the CARE I rocket experiment conducted from Wallops Island Virginia in September 2009.

  20. Airborne measurements of black carbon aerosol over the Southeastern U.S. during the Southeast Atmosphere Study (SAS) experiment

    NASA Astrophysics Data System (ADS)

    Markovic, M. Z.; Perring, A. E.; Schwarz, J. P.; Fahey, D. W.; Gao, R.; Watts, L.; Holloway, J.; Graus, M.; Warneke, C.; De Gouw, J. A.; Veres, P. R.; Roberts, J. M.; Middlebrook, A. M.; Welti, A.; Liao, J.

    2013-12-01

    The Southeast Atmosphere Study (SAS) field campaign was a large-scale, collaborative project, which took place in the Southeastern U.S. in June and July of 2013. The goal of the campaign was to investigate the impacts of biogenic and anthropogenic gases and aerosols on the formation of haze and anomalous climate cooling in the region. During SAS, a NOAA Single Particle Soot Photometer (SP2) instrument was utilized onboard NOAA WP-3D research aircraft for measurements of black carbon (BC) aerosol mass and microphysical properties. BC aerosol is emitted into the atmosphere from biomass burning (BB) and incomplete combustion of fossil and biofuel. Hence, BC sources are strongly linked to anthropogenic activity. BC aerosol is currently the second largest anthropogenic climate forcing agent after CO2(g), and its climate impacts, which depend on vertical burden and internal mixing, are not fully understood. In the Southeast, BC aerosol is expected to provide surface area for the condensation of semi-volatile products of VOC oxidation and subsequent formation of secondary organic aerosol (SOA). Hence, BC is expected to impact the haze formation and regional climate. In this work we present an overview of BC measurements during Southeast Nexus (SENEX) study, the NOAA contribution to SAS. Geographical variations in mass mixing ratios, mass size distributions, and mixing state of BC over the Southeast U.S. are discussed. Relationships of BC with carbon monoxide (CO), acetonitrile (ACN) and other trace gases are used to investigate the impacts of urban, BB, natural gas development, and power plant emissions on the distribution and properties of BC aerosol in the region. Among studied urban centers, St. Louis and Atlanta were determined to be the largest source regions of BC. A clear weekend effect in BC mass mixing ratios and microphysical properties was observed in the metropolitan Atlanta region. Compared to BB and urban centers, power plants and natural gas developments

  1. Characterizing the long-range transport of black carbon aerosols during Transport and Chemical Evolution over the Pacific (TRACE-P) experiment.

    PubMed

    Verma, Sunita; Worden, John; Payra, Swagata; Jourdain, Line; Shim, Changsub

    2009-07-01

    A major aircraft experiment Transport and Chemical Evolution over the Pacific (TRACE-P) mission over the NW Pacific in March-April 2001 was conducted to better understand how outflow from the Asian continent affects the composition of the global atmosphere. In this paper, a global climate model, GEOS-Chem is used to investigate possible black carbon aerosol contributions from TRACE-P region. Our result depicts that absorbing black carbon ("soot") significantly outflow during lifting to the free troposphere through warm conveyor belt and convection associated with this lifting. The GEOS-Chem simulation results show significant transport of black carbon aerosols from Asian regions to the Western Pacific region during the spring season. As estimated by GEOS-Chem simulations, approximately 25% of the black carbon concentrations over the western pacific originate from SE Asia in the spring.

  2. Organic aerosols

    SciTech Connect

    Penner, J.E.

    1994-01-01

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

  3. Combined aerosol in-situ measurements during the SALTRACE field experiment for the investigation of Saharan mineral dust microphysical and CCN properties and their spatial-temporal evolution during trans-Atlantic long-range transport

    NASA Astrophysics Data System (ADS)

    Walser, Adrian; Dollner, Maximilian; Sauer, Daniel; Weinzierl, Bernadett

    2015-04-01

    The Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) was a field experiment conducted in June/July 2013, which aimed to investigate the transport and modification of Saharan mineral dust from the Sahara across the Atlantic Ocean to the Caribbean. In addition to ground-based measurements and satellite remote sensing, the DLR Falcon research aircraft was equipped with a number of aerosol in-situ instruments to gain direct information on the properties of airborne aerosol such as size distributions, microphysical, optical and cloud-condensation nuclei (CCN) properties. For the first time, several outbreaks of Saharan dust were probed with the same airborne instrumentation on both sides of the Atlantic. During transport, various processes may take place that modify the aerosol composition. Dry and wet deposition lead to a size-dependent aerosol removal. In case of wet deposition, the removal additionally depends on the particle's ability to act as CCN. Processes in the aqueous phase in subsequently re-evaporating cloud droplets can further alter microphysical and CCN properties of re-released particles. All resulting changes in the size distribution and particle properties impact the radiative feedback and CCN activity of the aged aerosol. This study aims to use combined airborne in-situ measurements to retrieve and compare vertically resolved aerosol size distributions, microphysical and CCN properties for both, short-range transported Saharan dust in the Cape Verde region and long-range transported dust in the Caribbean. We use this data to investigate the influence of long-range transport and associated processes on those properties. We will present vertical profiles of size-resolved aerosol concentrations and volatile fractions as well as CCN activated fractions and draw conclusions for aerosol mixing state, CCN activation diameters and particle hygroscopicities. We will discuss differences in vertical profiles and

  4. Radiative Effects of Aerosols

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.

    1996-01-01

    During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in aerosol optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size-resolved aerosol microphysics and chemistry. Both profiles included a pollution haze from Europe but the second also included the effect of a Saharan dust layer above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) aerosol were determined and thermal analysis of the pollution haze indicated that the fine aerosol was composed primarily of a sulfate/water mixture with a refractory soot-like core. The soot core increased the calculated extinction by about 10% in the most polluted drier layer relative to a pure sulfate aerosol but had significantly less effect at higher humidities. A 3 km descent through a boundary layer air mass dominated by pollutant aerosol with relative humidities (RH) 10-77% yielded a close agreement between the measured and calculated aerosol optical depths (550 nm) of 0.160 (+/- 0.07) and 0. 157 (+/- 0.034) respectively. During descent the aerosol mass scattering coefficient per unit sulfate mass varied from about 5 to 16 m(exp 2)/g and primarily dependent upon ambient RH. However, the total scattering coefficient per total fine mass was far less variable at about 4+/- 0.7 m(exp 2)/g. A subsequent descent through a Saharan dust layer located above the pollution aerosol layer revealed that both layers contributed similarly to aerosol optical depth. The scattering per unit mass of the coarse aged dust was estimated at 1.1 +/- 0.2 m(exp 2)/g. The large difference (50%) in measured and calculated optical depth for the dust layer exceeded measurements.

  5. Some effects of cloud-aerosol interaction on cloud microphysics structure and precipitation formation: numerical experiments with a spectral microphysics cloud ensemble model

    NASA Astrophysics Data System (ADS)

    Khain, A.; Pokrovsky, A.; Sednev, I.

    A spectral microphysics Hebrew University Cloud Model (HUCM) is used to evaluate some effects of cloud-aerosol interaction on mixed-phase cloud microphysics and aerosol particle size distribution in the region of the Eastern Mediterranean coastal circulation. In case of a high concentration of aerosol particles (APs), the rate of warm rain formation is several times lower, a significant fraction of droplets ascends above the freezing level. These drops produce a large amount of comparably small graupel particles and ice crystals. The warm rain from these clouds is less intense as compared to clouds with low drop concentration. At the same time, melted rain from clouds with high droplet concentration is more intense than from low drop concentration clouds. Melted rain can take place downwind at a distance of several tens of kilometers from the convective zone. It is shown that APs entering clouds above the cloud base influence the evolution of the drop size spectrum and the rate of rain formation. The chemical composition of APs influences the concentration of nucleated droplets and, therefore, changes accumulated rain significantly (in our experiments these changes are of 25-30%). Clouds in a coastal circulation influence significantly the concentration and size distribution of APs. First, they decrease the concentration of largest APs by nucleation scavenging. In our experiments, about 40% of APs were nucleated within clouds. The remaining APs are transported to middle levels by cloud updrafts and then enter the land at the levels of 3 to 7 km. In our experiments, the concentration of small APs increased several times at these levels. The cut off APs spectrum with an increased concentration of small APs remains downwind of the convective zone for several of tens and even hundreds of kilometers. The schemes of drop nucleation (based on the dependence of nucleated drop concentration on supersaturation in a certain power) and autoconversion (based on the Kessler

  6. Lightning activity for the July 10, 1996, storm during the Stratosphere-Troposphere Experiment: Radiation, Aerosol, and Ozone-A (STERAO-A) experiment

    NASA Astrophysics Data System (ADS)

    Defer, Eric; Blanchet, Patrice; ThéRy, Claire; Laroche, Pierre; Dye, James E.; Venticinque, Martin; Cummins, Kenneth L.

    2001-05-01

    We have analyzed the lightning activity recorded during the Stratosphere-Troposphere Experiment: Radiation, Aerosols, and Ozone (STERAO-A) July 10, 1996, storm by the Office National d'Etudes et de Recherches Aérospatiales (ONERA) lightning VHF interferometer and the National Lightning Detection Network (NLDN) system. Both cloud-to-ground and total lightning activity were observed and studied for the entire 5-hour life of the storm. The July 10 storm was a multicellular complex, which became unicellular during the last hour. It primarily exhibited high intracloud activity with only 1.5% cloud-to-ground flashes. The maximum value of the total flash rate was 58 flashes per minute. Cloud-to-ground (CG) flashes occurred after some intracloud flashes with a delay ranging from 3 to 26 min for the different cells of the storm. Our study revealed that measured flash duration ranged from 23 μs to 1.8 s. Flash duration, averaged over 5-min periods, increased during the storm life. Short-duration flashes (<1 ms) did not occur until 30 min after the initial flash in the storm when the 50 dBZ vertical profile reached 8 km mean sea level (msl). The short-duration flashes were recorded in cells where high reflectivity reached high altitude. Detailed analysis showed that the ONERA and NLDN reports were temporally and spatially consistent in the measurement of the cloud-to-ground flashes. Finally, we developed a new technique to distinguish negative CG flashes from other flashes by identifying the VHF signature of the negative downward stepped leader-return stroke process in the flash VHF signal.

  7. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Columnar Water Vapor During the Puerto Rico Dust Experiment, and Comparison with Land, Aircraft, and Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km ASL reproduce the vertical structure measured by coincident aircraft in-situ measurements of total aerosol number and surface area concentration. Calculations show that the spectral dependence of AOD was small (mean Angstrom wavelength exponents of approximately 0.20) within three atmospheric layers defined as the total column beneath the top of each aircraft profile, the region beneath the trade wind inversion, and the region within the Saharan Air Layer (SAL) above the trade inversion. This spectral behavior is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in-situ measurements by a chilled mirror dewpoint hygrometer agree to within approximately 4% (0.13 g/sq cm). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004 to 0.030 with coincident data obtained with an AERONET Sun/sky Cimel radiometer located at Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by a mean of 0.74 g/sq cm (approximately 21 %) for the 2.9-3.9 g/sq cm measured by AATS-6. Comparison of AATS-6 aerosol extinction values obtained during four aircraft ascents over Cabras Island with corresponding values calculated from coincident aerosol backscatter measurements by a ground-based micro-pulse lidar (MPL-Net) located at Cabras yields a similar vertical structure above the trade

  8. Single-particle characterization of atmospheric aerosols collected at Gosan, Korea, during the Asian Pacific Regional Aerosol Characterization Experiment field campaign using low-Z (atomic number) particle electron probe X-ray microanalysis.

    PubMed

    Geng, Hong; Cheng, Fangqin; Ro, Chul-Un

    2011-11-01

    A quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA), namely low-Z (atomic number) particle EPMA, was used to characterize the chemical compositions of the individual aerosol particles collected at the Gosan supersite, Jeju Island, Korea, as a part of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). On 4-10 April 2001 just before a severe dust storm arrived, seven sets of aerosol samples were obtained by a seven-stage May cascade impactor with a flow rate of 20 L/min. Overall 11,200 particles on stages 1-6 with cutoff diameters of 16, 8, 4, 2, 1, and 0.5 microm, respectively, were examined and classified based on their secondary electron images and X-ray spectra. In general, sea salt particles were the most frequently encountered, followed by mineral dust, organic carbon (OC)-like, (NH4)2SO4/NH4HSO4-containing, elemental carbon (EC)-like, Fe-rich, and K-rich particles. Sea salt and mineral dust particles had a higher relative abundance on stages 1-5, whereas OC-like, (NH4)2SO4/NH4HSO4-containing, Fe-rich, and K-rich particles were relatively abundant on stage 6. The analysis on relative number abundances of various particle types combined with 72-hr backward air mass trajectories indicated that a lot of reacted sea salt and reacted mineral dust (with airborne NOx and SO2 or their acidic products) and OC-like particles were carried by the air masses passing over the Yellow Sea (for sample "10 April") and many NH4HSO4/ (NH4)2SO4-containing particles were carried by the air masses passing over the Sea of Japan and Korea Strait (for samples "4-9 April"). It was concluded that the atmosphere over Jeju Island was influenced by anthropogenic SO2 and NOx, organic compounds, and secondary aerosols when Asian dust was absent.

  9. Baseline radon detectors for shipboard use: Development and deployment in the First Aerosol Characterization Experiment (ACE 1)

    NASA Astrophysics Data System (ADS)

    Whittlestone, S.; Zahorowski, W.

    1998-01-01

    A new design of two-filter radon detector has been developed for measurement of extremely low levels of radon in the harsh environments on board ships and remote islands. These were needed for the First Aerosol Characterization (ACE 1) multiplatform experiment in the Southern Ocean. By employing an internal recirculation system and a wire mesh screen as the second filter it has been possible to reduce the power consumption by as much as a factor of 10 and the weight and cost by a factor of 2 compared to current designs of comparable sensitivity. A very high efficiency of 0.38 count s-1 Bq-1 radon in the instrument has been achieved by counting while sampling. This is a key parameter because the larger this number, the smaller the volume and power consumption of the detector. Two air flow paths are used to separate the high flow rate needed to prevent loss of radon daughters to the walls of the detector and the lower flow rate needed to change the air sample in the instrument. As a result, the inlet air lines and delay chamber needed to remove thoron are compact. With a volume of 750 L the detectors used on board ships for ACE 1 had a sensitivity of about 0.2 counts s-1 Bq-1 m-3 and a lower limit of detection of 40 mBq m-3 for a 1 hour count. An instrument with a volume of 10 m3 and incorporating improvements made since ACE 1 could be expected to have sensitivity of 3.7 c s-1 Bq-1 m-3 and a lower limit of detection of 2 mBq m-3. At 45 min the time resolution is twice as good as that of instruments using a low internal flow rate, but not as good as instruments with a moving filter, where the sampling period is precisely defined. Dual-flow loop radon detectors with screens have the virtues of simplicity and freedom from routine maintenance. This new technology extends the range of sites at which baseline radon measurements can be made to remote areas with little regular technical support and a harsh environment.

  10. Aerosol classification by airborne high spectral resolution lidar observations

    NASA Astrophysics Data System (ADS)

    Groß, S.; Esselborn, M.; Weinzierl, B.; Wirth, M.; Fix, A.; Petzold, A.

    2012-10-01

    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.

  11. Long- and/or short-range transportation of local Asian aerosols in DRAGON-Osaka Experiment

    NASA Astrophysics Data System (ADS)

    Nakata, M.; Sano, I.; Mukai, S.; Holben, B. N.

    2013-12-01

    This work intends to demonstrate the spatial and temporal variation of atmospheric particles in East Asia, especially around AERONET (Aerosol Robotics Network) -Osaka site during Dragon Asia period in the spring of 2012, named Dragon-Osaka. It is known that the air pollution in East Asia becomes to be severe due to both the increasing emissions of the anthropogenic aerosols associated with economic growth and the complicated behavior of natural aerosols. Thus the precise observations of atmospheric particles in East Asia are desired. Osaka is the second big city in Japan and a typical Asian urban area. The population of the region is around 20 millions including neighbor prefectures. Therefore, air quality in the region is slightly bad compared to remote area due to industries and auto mobiles. In recent years, Asian dusts and anthropogenic small particles transported from China and cover those cities throughout year. AERONET Osaka site was established in 2002 on the campus of Kinki University. Nowadays, LIDAR (Light Detection and Ranging), an SPM sampler (SPM-613D, Kimoto Electric, Japan) and others are available on the roof of a building. The site data are useful for algorithm development of aerosol retrieval over busy city. On the other hand, human activities in this region also emit the huge amount of pollutions, thus it is needed to investigate the local distribution of aerosols in this region. In order to investigate change of aerosol properties, PM-individual analysis is made with scanning electron microscope (SEM) coupled with energy dispersive X-ray analyzer (EDX). SEM/EDX is an effective instrument to observe the surface microstructure and analyze the chemical composition of such materials as metals, powders, biological specimens, etc. We used sampling data from the SPM sampler at AERONET Osaka site. During a period of DRAGON-Asia, high concentrations of air pollutant were observed on the morning of March 11 in Fukue Island in the East China Sea. On the

  12. CALWATER-2 An Experiment Exploring the Roles of Atmospheric Rivers and Aerosols in Modulating U.S. West Coast Precipitation in a Changing Climate

    NASA Astrophysics Data System (ADS)

    Ralph, F. M.; Prather, K. A.; Cayan, D. R.; Dettinger, M. D.; Fairall, C. W.; Leung, L.; Rosenfeld, D.; Rutledge, S. A.; Spackman, J.; Waliser, D. E.

    2013-12-01

    Two phenomena that play key roles in the variability of the water supply and the incidence of extreme precipitation events along the West Coast of the United States are: 1) Atmospheric rivers (ARs), which deliver much of the precipitation associated with major storms along the U.S. West Coast, and 2) Aerosols--from local sources as well as those transported from remote continents--which can modulate western U.S. precipitation. A better understanding of these processes is needed to reduce uncertainties in weather predictions and climate projections of extreme precipitation and its effects, including the provision of beneficial water supply. This presentation summarizes science gaps associated with (1) the evolution and structure of ARs including cloud and precipitation processes and air-sea interaction, and (2) aerosol interaction with ARs and the impact on precipitation, including locally-generated aerosol effects on orographic precipitation along the U.S. West Coast. A set of science investigations, called CalWater 2, have been proposed over the next several years to fill these gaps including a targeted set of aircraft and ship-based measurements and associated evaluation of data over regions offshore of California and in the eastern Pacific for an intensive observing period between December 2014 and March 2015. DOE's Atmospheric Radiation Measurement (ARM) program and NOAA are coordinating on deployment of airborne and ship-borne facilities for this period, including a DOE-sponsored study called ACAPEX (ARM Cloud Aerosol and Precipitation Experiment) that was proposed in the context of CalWater 2. A broad 5-year vision of an interagency effort to address these science gaps will be presented, and informal input into this planning is being solicited through this presentation, including consideration of potential synergistic connections to other relevant activities. The CalWater 2 white paper was prepared by a team of meteorologists, hydrologists, climate scientists

  13. Results of a comprehensive atmospheric aerosol-radiation experiment in the southwestern United States. I - Size distribution, extinction optical depth and vertical profiles of aerosols suspended in the atmosphere. II - Radiation flux measurements and

    NASA Technical Reports Server (NTRS)

    Deluisi, J. J.; Furukawa, F. M.; Gillette, D. A.; Schuster, B. G.; Charlson, R. J.; Porch, W. M.; Fegley, R. W.; Herman, B. M.; Rabinoff, R. A.; Twitty, J. T.

    1976-01-01

    Results are reported for a field test that was aimed at acquiring a sufficient set of measurements of aerosol properties required as input for radiative-transfer calculations relevant to the earth's radiation balance. These measurements include aerosol extinction and size distributions, vertical profiles of aerosols, and radiation fluxes. Physically consistent, vertically inhomogeneous models of the aerosol characteristics of a turbid atmosphere over a desert and an agricultural region are constructed by using direct and indirect sampling techniques. These results are applied for a theoretical interpretation of airborne radiation-flux measurements. The absorption term of the complex refractive index of aerosols is estimated, a regional variation in the refractive index is noted, and the magnitude of solar-radiation absorption by aerosols and atmospheric molecules is determined.

  14. Meeting Review: Airborne Aerosol Inlet Workshop

    NASA Technical Reports Server (NTRS)

    Baumgardner, Darrel; Huebert, Barry; Wilson, Chuck

    1991-01-01

    Proceedings from the Airborne Aerosol Inlet Workshop are presented. The two central topics of discussion were the role of aerosols in atmospheric processes and the difficulties in characterizing aerosols. The following topics were discussed during the working sessions: airborne observations to date; identification of inlet design issues; inlet modeling needs and directions; objectives for aircraft experiments; and future laboratory and wind tunnel studies.

  15. Aerosol classification by airborne high spectral resolution lidar observations

    NASA Astrophysics Data System (ADS)

    Groß, S.; Esselborn, M.; Weinzierl, B.; Wirth, M.; Fix, A.; Petzold, A.

    2013-03-01

    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 mixture, 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 supported by backward trajectory analysis and validated with in-situ measurements. Our results demonstrate that the developed aerosol mask is capable to identify complex stratifications with different aerosol types throughout the atmosphere.

  16. An intercomparison of SAGE and SBUV ozone observations for March and April 1979. [stratospheric aerosol and gas experiment solar backscatterd ultraviolet

    NASA Technical Reports Server (NTRS)

    Cunnold, D. M.; Pitts, M. C.; Trepte, C. R.

    1984-01-01

    Thirty-eight latitudinal cross sections of stratospheric ozone observed by the SAGE (Stratospheric Aerosol and Gas Experiment) and SBUV (Solar Backscattered Ultraviolet) satellite instruments on the same days in March and April 1979 and at approximately the same latitude are compared. Differences in the zonal-mean mixing ratios are found. At pressures less than 5 mbar, SAGE gives approximately 20 percent larger mixing ratios at tropical latitudes (after a correction has been applied for the expected diurnal variation of ozone). The uncorrelated portion of the SBUV variances are smaller than the SAGE noise variances at altitudes above 10 mbar, which indicates that the SBUV experiment should provide excellent detectability of longitudinal ozone variations.

  17. Organic Composition of PM2.5 and Size-Segregated Aerosols During the 2002 Bay Regional Atmospheric Chemistry Experiment (BRACE), Florida, USA

    NASA Astrophysics Data System (ADS)

    Tremblay, R. T.; Zika, R. G.

    2003-12-01

    Aerosol samples were collected for the analysis of organic source markers using a Tisch Environmental PM2.5 high volume sampler and two Micro Orifice Uniform Deposit Impactors (MOUDIs) as part of the Bay Regional Atmospheric Chemistry Experiment (BRACE) in Tampa, Florida. PM2.5 samples were collected at ground level on quartz fiber filters (QFF) while size-segregated samples were collected 12 meter above ground level on aluminum foil discs. MOUDIs with aerodynamic cut diameters of 18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32 and 0.17 um were used. Samples were collected on a 24 hour schedule. The collected samples were solvent extracted using a mixture of dichloromethane/acetone/hexane, concentrated and then analyzed using a gas chromatograph/mass spectrometer (GC/MS) operated in single ion mode. PM2.5 extracts were analyzed using conventional splitless low volume injections (1 ul). Size-segregated aerosol extracts were analyzed using a Hewlett-Packard Programmable Temperature Vaporizing inlet (PTV) combined with large volume injections (80ul). Excellent chromatographic resolutions were obtained with either a 30 or 60 meter long RTX-5MS, 0.25 mm I.D. column. Target compounds were chosen to cover the range of potential sources and included alkanes and polycyclic aromatic hydrocarbons (PAH). Investigation of potential aerosol sources for different particle sizes using known organic markers and source profiles will be presented. Relationship between the collected PM2.5 and size-segregated samples will be studied. Size distributions of carbon preference indices (CPI), percent wax n-alkanes (%WNA) and concentration of selected compounds will be discussed.

  18. The new Mediterranean background monitoring station of Ersa, Cape Corsica: A long term Observatory component of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx)

    NASA Astrophysics Data System (ADS)

    Dulac, Francois

    2013-04-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr/) is a French initiative supported by the MISTRALS program (Mediterranean Integrated Studies at Regional And Locals Scales, http://www.mistrals-home.org). It aims at a scientific assessment of the present and future state of the atmospheric environment in the Mediterranean Basin, and of its impacts on the regional climate, air quality, and marine biogeochemistry. The major stake is an understanding of the future of the Mediterranean region in a context of strong regional anthropogenic and climatic pressures. The target of ChArMEx is short-lived particulate and gaseous tropospheric trace species which are the cause of poor air quality events, have two-way interactions with climate, or impact the marine biogeochemistry. In order to fulfill these objectives, important efforts have been put in 2012 in order to implement the infrastructure and instrumentation for a fully equipped background monitoring station at Ersa, Cape Corsica, a key location at the crossroads of dusty southerly air masses and polluted outflows from the European continent. The observations at this station began in June 2012 (in the context of the EMEP / ACTRIS / PEGASOS / ChArMEx campaigns). A broad spectrum of aerosol properties is also measured at the station, from the chemical composition (off-line daily filter sampling in PM2.5/PM10, on-line Aerosol Chemical Speciation Monitor), ground optical properties (extinction/absorption/light scattering coeff. with 1-? CAPS PMex monitor, 7-? Aethalometer, 3-? Nephelometer), integrated and vertically resolved optical properties (4-? Cimel sunphotometer and LIDAR, respective), size distribution properties (N-AIS, SMPS, APS, and OPS instruments), mass (PM1/PM10 by TEOM/TEOM-FDMS), hygroscopicity (CCN), as well as total insoluble deposition. So far, real-time measurement of reactive gases (O3, CO, NO, NO2), and off-line VOC measurements (cylinders, cartridges) are also

  19. Aerosol Disinfection Capacity of Slightly Acidic Hypochlorous Acid Water Towards Newcastle Disease Virus in the Air: An In Vivo Experiment.

    PubMed

    Hakim, Hakimullah; Thammakarn, Chanathip; Suguro, Atsushi; Ishida, Yuki; Nakajima, Katsuhiro; Kitazawa, Minori; Takehara, Kazuaki

    2015-12-01

    Existence of bioaerosol contaminants in farms and outbreaks of some infectious organisms with the ability of transmission by air increase the need for enhancement of biosecurity, especially for the application of aerosol disinfectants. Here we selected slightly acidic hypochlorous acid water (SAHW) as a candidate and evaluated its virucidal efficacy toward a virus in the air. Three-day-old conventional chicks were challenged with 25 doses of Newcastle disease live vaccine (B1 strain) by spray with nebulizer (particle size <3 μm in diameter), while at the same time reverse osmosis water as the control and SAHW containing 50 or 100 parts per million (ppm) free available chlorine in pH 6 were sprayed on the treated chicks with other nebulizers. Exposed chicks were kept in separated cages in an isolator and observed for clinical signs. Oropharyngeal swab samples were collected from 2 to 5 days postexposure from each chick, and then the samples were titrated with primary chicken kidney cells to detect the virus. Cytopathic effects were observed, and a hemagglutination test was performed to confirm the result at 5 days postinoculation. Clinical signs (sneezing) were recorded, and the virus was isolated from the control and 50 ppm treatment groups, while no clinical signs were observed in and no virus was isolated from the 100 ppm treatment group. The virulent Newcastle disease virus (NDV) strain Sato, too, was immediately inactivated by SAHW containing 50 ppm chlorine in the aqueous phase. These data suggest that SAHW containing 100 ppm chlorine can be used for aerosol disinfection of NDV in farms. PMID:26629621

  20. Aerosol Disinfection Capacity of Slightly Acidic Hypochlorous Acid Water Towards Newcastle Disease Virus in the Air: An In Vivo Experiment.

    PubMed

    Hakim, Hakimullah; Thammakarn, Chanathip; Suguro, Atsushi; Ishida, Yuki; Nakajima, Katsuhiro; Kitazawa, Minori; Takehara, Kazuaki

    2015-12-01

    Existence of bioaerosol contaminants in farms and outbreaks of some infectious organisms with the ability of transmission by air increase the need for enhancement of biosecurity, especially for the application of aerosol disinfectants. Here we selected slightly acidic hypochlorous acid water (SAHW) as a candidate and evaluated its virucidal efficacy toward a virus in the air. Three-day-old conventional chicks were challenged with 25 doses of Newcastle disease live vaccine (B1 strain) by spray with nebulizer (particle size <3 μm in diameter), while at the same time reverse osmosis water as the control and SAHW containing 50 or 100 parts per million (ppm) free available chlorine in pH 6 were sprayed on the treated chicks with other nebulizers. Exposed chicks were kept in separated cages in an isolator and observed for clinical signs. Oropharyngeal swab samples were collected from 2 to 5 days postexposure from each chick, and then the samples were titrated with primary chicken kidney cells to detect the virus. Cytopathic effects were observed, and a hemagglutination test was performed to confirm the result at 5 days postinoculation. Clinical signs (sneezing) were recorded, and the virus was isolated from the control and 50 ppm treatment groups, while no clinical signs were observed in and no virus was isolated from the 100 ppm treatment group. The virulent Newcastle disease virus (NDV) strain Sato, too, was immediately inactivated by SAHW containing 50 ppm chlorine in the aqueous phase. These data suggest that SAHW containing 100 ppm chlorine can be used for aerosol disinfection of NDV in farms.

  1. Aerosolized Antibiotics.

    PubMed

    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.

  2. Global Aerosols

    Atmospheric Science Data Center

    2013-04-19

    ... sizes and from multiple sources, including biomass burning, mineral dust, sea salt and regional industrial pollution. A color scale is ... desert source region. Deserts are the main sources of mineral dust, and MISR obtains aerosol optical depth at visible wavelengths ...

  3. Indian aerosols: present status.

    PubMed

    Mitra, A P; Sharma, C

    2002-12-01

    This article presents the status of aerosols in India based on the research activities undertaken during last few decades in this region. Programs, like International Geophysical Year (IGY), Monsoon Experiment (MONEX), Indian Middle Atmospheric Program (IMAP) and recently conducted Indian Ocean Experiment (INDOEX), have thrown new lights on the role of aerosols in global change. INDOEX has proved that the effects of aerosols are no longer confined to the local levels but extend at regional as well as global scales due to occurrence of long range transportation of aerosols from source regions along with wind trajectories. The loading of aerosols in the atmosphere is on rising due to energy intensive activities for developmental processes and other anthropogenic activities. One of the significant observation of INDOEX is the presence of high concentrations of carbonaceous aerosols in the near persistent winter time haze layer over tropical Indian Ocean which have probably been emitted from the burning of fossil-fuels and biofuels in the source region. These have significant bearing on the radiative forcing in the region and, therefore, have potential to alter monsoon and hydrological cycles. In general, the SPM concentrations have been found to be on higher sides in ambient atmosphere in many Indian cities but the NOx concentrations have been found to be on lower side. Even in the haze layer over Indian Ocean and surrounding areas, the NOx concentrations have been reported to be low which is not conducive of O3 formation in the haze/smog layer. The acid rain problem does not seem to exist at the moment in India because of the presence of neutralizing soil dust in the atmosphere. But the high particulate concentrations in most of the cities' atmosphere in India are of concern as it can cause deteriorated health conditions. PMID:12492171

  4. Indian aerosols: present status.

    PubMed

    Mitra, A P; Sharma, C

    2002-12-01

    This article presents the status of aerosols in India based on the research activities undertaken during last few decades in this region. Programs, like International Geophysical Year (IGY), Monsoon Experiment (MONEX), Indian Middle Atmospheric Program (IMAP) and recently conducted Indian Ocean Experiment (INDOEX), have thrown new lights on the role of aerosols in global change. INDOEX has proved that the effects of aerosols are no longer confined to the local levels but extend at regional as well as global scales due to occurrence of long range transportation of aerosols from source regions along with wind trajectories. The loading of aerosols in the atmosphere is on rising due to energy intensive activities for developmental processes and other anthropogenic activities. One of the significant observation of INDOEX is the presence of high concentrations of carbonaceous aerosols in the near persistent winter time haze layer over tropical Indian Ocean which have probably been emitted from the burning of fossil-fuels and biofuels in the source region. These have significant bearing on the radiative forcing in the region and, therefore, have potential to alter monsoon and hydrological cycles. In general, the SPM concentrations have been found to be on higher sides in ambient atmosphere in many Indian cities but the NOx concentrations have been found to be on lower side. Even in the haze layer over Indian Ocean and surrounding areas, the NOx concentrations have been reported to be low which is not conducive of O3 formation in the haze/smog layer. The acid rain problem does not seem to exist at the moment in India because of the presence of neutralizing soil dust in the atmosphere. But the high particulate concentrations in most of the cities' atmosphere in India are of concern as it can cause deteriorated health conditions.

  5. Estimation of lifetime of carbonaceous aerosol from open crop residue burning during Mount Tai Experiment 2006 (MTX2006)

    NASA Astrophysics Data System (ADS)

    Pan, X. L.; Kanaya, Y.; Wang, Z. F.; Komazaki, Y.; Taketani, F.; Akimoto, H.; Pochanart, P.; Liu, Y.

    2012-06-01

    Studying the emission ratios of carbonaceous aerosols (element carbon, EC, and organic carbon, OC) from open biomass burning helps to reduce uncertainties in emission inventories and provides necessary constraints for model simulations. We measured apparent elemental carbon (ECa) and OC concentrations at the summit of Mount Tai (Mt. Tai) during intensive open crop residue burning (OCRB) episodes using a Sunset OCEC analyzer. Equivalent black carbon (BCe) concentrations were determined using a Multiple Angle Absorption Photometer (MAAP). In the fine particle mode, OC and EC showed strong correlations (r > 0.9) with carbon monoxide (CO). Footprint analysis using the FLEXPART_WRF model indicated that OCRB in central east China (CEC) had a significant influence on ambient carbonaceous aerosol loadings at the summit of Mt. Tai. ΔECa/ΔCO ratios resulting from OCRB plumes were 14.3 ± 1.0 ng m-3 ppbv-1 at Mt. Tai. This ratio was more than three times those resulting from urban pollution in CEC, demonstrating that significant concentrations of soot particles were released from OCRB. ΔOC/ΔCO ratio from fresh OCRB plumes was found to be 41.9 ± 2.6 ng m-3 ppbv-1 in PM1. The transport time of smoke particles was estimated using the FLEXPART_WRF tracer model by releasing inert particles from the ground layer inside geographical regions where large numbers of hotspots were detected by a MODIS satellite sensor. Fitting regressions using the e-folding exponential function indicated that the removal efficiency of OC (normalized to CO) was much larger than that of ECa mass, with mean lifetimes of 27 h (1.1 days) for OC and 105 h (4.3 days) for ECa, respectively. The lifetime of black carbon estimated for the OCRB events in east China was comparably lower than the values normally adopted in the transport models. Short lifetime of organic carbon highlighted the vulnerability of OC to cloud scavenging in the presence of water-soluble organic species from biomass combustion.

  6. Aerosol in the Pacific troposphere

    NASA Technical Reports Server (NTRS)

    Clarke, Antony D.

    1989-01-01

    The use of near real-time optical techniques is emphasized for the measurement of mid-tropospheric aerosol over the Central Pacific. The primary focus is on measurement of the aerosol size distribution over the range of particle diameters from 0.15 to 5.0 microns that are essential for modeling CO2 backscatter values in support of the laser atmospheric wind sounder (LAWS) program. The measurement system employs a LAS-X (Laser Aerosol Spectrometer-PMS, Boulder, CO) with a custom 256 channel pulse height analyzer and software for detailed measurement and analysis of aerosol size distributions. A thermal preheater system (Thermo Optic Aerosol Descriminator (TOAD) conditions the aerosol in a manner that allows the discrimination of the size distribution of individual aerosol components such as sulfuric acid, sulfates and refractory species. This allows assessment of the relative contribution of each component to the BCO2 signal. This is necessary since the different components have different sources, exhibit independent variability and provide different BCO2 signals for a given mass and particle size. Field activities involve experiments designed to examine both temporal and spatial variability of these aerosol components from ground based and aircraft platforms.

  7. SAGE II aerosol correlative observations - Profile measurements

    NASA Technical Reports Server (NTRS)

    Osborn, M. T.; Rosen, J. M.; Mccormick, M. P.; Wang, Pi-Huan; Livinfston, J. M.

    1989-01-01

    Profiles of the aerosol extinction measurements from the Stratospheric Aerosol and Gas Experiment (SAGE) II are compared with profiles from five correlative experiments between November 1984 and July 1986. The correlative profiles were derived from six-channel dustsonde measurements and two-wavelength lidar backscatter data. The correlation between the dustsonde- and lidar-derived measurements and the SAGE II data is good, validating the SAGE II lower stratospheric aerosol extinction measurements.

  8. Tropospheric Aerosols

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

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

  9. An overview of the Ice Nuclei Research Unit Jungfraujoch/Cloud and Aerosol Characterization Experiment 2013 (INUIT-JFJ/CLACE-2013)

    NASA Astrophysics Data System (ADS)

    Schneider, Johannes

    2014-05-01

    Ice formation in mixed phase tropospheric clouds is an essential prerequisite for the formation of precipitation at mid-latitudes. Ice formation at temperatures warmer than -35°C is only possible via heterogeneous ice nucleation, but up to now the exact pathways of heterogeneous ice formation are not sufficiently well understood. The research unit INUIT (Ice NUcleation research unIT), funded by the Deutsche Forschungsgemeinschaft (DFG FOR 1525) has been established in 2012 with the objective to investigate heterogeneous ice nucleation by combination of laboratory studies, model calculation and field experiments. The main field campaign of the INUIT project (INUIT-JFJ) was conducted at the High Alpine Research Station Jungfraujoch (Swiss Alps, 3580 m asl) during January and February 2013, in collaboration with several international partners in the framework of CLACE2013. The instrumentation included a large set of aerosol chemical and physical analysis instruments (particle counters, particle sizers, particle mass spectrometers, cloud condensation nuclei counters, ice nucleus counters etc.), that were operated inside the Sphinx laboratory and sampled in mixed phase clouds through two ice selective inlets (Ice-CVI, ISI) as well as through a total aerosol inlet that was used for out-of-cloud aerosol measurements. Besides the on-line measurements, also samples for off-line analysis (ESEM, STXM) have been taken in and out of clouds. Furthermore, several cloud microphysics instruments were operated outside the Sphinx laboratory. First results indicate that a large fraction of ice residues sampled from mixed phase clouds contain organic material, but also mineral dust. Soot and lead were not found to be enriched in ice residues. The concentration of heterogeneous ice nuclei was found to be variable (ranging between < 1 and > 100 per liter) and to be strongly dependent on the operating conditions of the respective IN counter. The number size distribution of ice residues

  10. Large outdoor chamber experiments and computer simulations: (I) Secondary organic aerosol formation from the oxidation of a mixture of d-limonene and α-pinene

    NASA Astrophysics Data System (ADS)

    Li, Qianfeng; Hu, Di; Leungsakul, Sirakarn; Kamens, Richard M.

    This work merges kinetic models for α-pinene and d-limonene which were individually developed to predict secondary organic aerosol (SOA) formation from these compounds. Three major changes in the d-limonene and α-pinene combined mechanism were made. First, radical-radical reactions were integrated so that radicals formed from both individual mechanisms all reacted with each other. Second, all SOA model species from both compounds were used to calculate semi-volatile partitioning for new semi-volatiles formed in the gas phase. Third particle phase reactions for particle phase α-pinene and d-limonene aldehydes, carboxylic acids, etc. were integrated. Experiments with mixtures of α-pinene and d-limonene, nitric oxide (NO), nitrogen dioxide (NO 2), and diurnal natural sunlight were carried out in a dual 270 m 3 outdoor Teflon film chamber located in Pittsboro, NC. The model closely simulated the behavior and timing for α-pinene, d-limonene, NO, NO 2, O 3 and SOA. Model sensitivities were tested with respect to effects of d-limonene/α-pinene ratios, initial hydrocarbon to NO x (HC 0/NO x) ratios, temperature, and light intensity. The results showed that SOA yield ( YSOA) was very sensitive to initial d-limonene/α-pinene ratio and temperature. The model was also used to simulate remote atmospheric SOA conditions that hypothetically could result from diurnal emissions of α-pinene, d-limonene and NO x. We observed that the volatility of the simulated SOA material on the aging aerosol decreased with time, and this was consistent with chamber observations. Of additional importance was that our simulation did not show a loss of SOA during the daytime and this was consistent with observed measurements.

  11. Particulate polycyclic aromatic hydrocarbons in the Atlantic and Indian Ocean atmospheres during the Indian Ocean Experiment and Aerosols99: Continental sources to the marine atmosphere

    NASA Astrophysics Data System (ADS)

    Crimmins, Bernard S.; Dickerson, Russell R.; Doddridge, Bruce G.; Baker, Joel E.

    2004-03-01

    Polycyclic aromatic hydrocarbons (PAHs), mutagenic compounds predominantly derived from combustion, have been used as markers of combustion sources to the atmosphere. Marine aerosol collected aboard the NOAA R/V Ronald Brown during the Aerosols99 and the Indian Ocean Experiment (INDOEX) projects was analyzed for PAHs to assess the continental impact of combustion-derived particulate matter on the Atlantic and Indian Ocean atmospheres. PAH concentrations in the Atlantic and southern Indian Ocean atmospheres were consistent and low, ranging from <0.45 pg/m3 for coronene to 30 pg/m3 for 9, 10-dimethylanthracene. PAH concentrations increased ten fold as the ship crossed the Intertropical Convergence Zone (ITCZ) into the northern Indian Ocean, indicating an increased anthropogenic influence. PAH concentrations over the northern Indian Ocean atmosphere were approximately an order of magnitude greater than those in the northern Atlantic Ocean atmosphere. PAH composition profiles over the northern Indian Ocean were specific to wind regimes and influenced by a combination of biomass and fossil fuel combustion. This was supported by significant correlations between select PAHs and organic carbon (OC), elemental carbon (EC), SO4-2 and K+ for particular wind regimes. Indeno[1,2,3-cd]pyrene/EC ratios used as a combustion source marker suggest that fossil fuel combustion, rather than biomass burning, is the predominant source of PAHs to the Northern Hemisphere Indian Ocean atmosphere. Interestingly, fossil fuel consumption in the Indian sub-continent is a fraction of that in Europe and the United States but the soot and PAH levels in the adjacent Northern Indian Ocean atmosphere are significantly greater than those in the Northern Atlantic atmosphere.

  12. Easy Volcanic Aerosol

    NASA Astrophysics Data System (ADS)

    Toohey, Matthew; Stevens, Bjorn; Schmidt, Hauke; Timmreck, Claudia

    2016-04-01

    Radiative forcing by stratospheric sulfate aerosol of volcanic origin is one of the strongest drivers of natural climate variability. Transient model simulations attempting to match observed climate variability, such as the CMIP historical simulations, rely on volcanic forcing reconstructions based on observations of a small sample of recent eruptions and coarse proxy data for eruptions before the satellite era. Volcanic forcing data sets used in CMIP5 were provided either in terms of optical properties, or in terms of sulfate aerosol mass, leading to significant inter-model spread in the actual volcanic radiative forcing produced by models and in their resulting climate responses. It remains therefore unclear to what degree inter-model spread in response to volcanic forcing represents model differences or variations in the forcing. In order to isolate model differences, Easy Volcanic Aerosol (EVA) provides an analytic representation of volcanic stratospheric aerosol forcing, based on available observations and aerosol model results, prescribing the aerosol's radiative properties and primary modes of spatial and temporal variability. In contrast to regriddings of observational data, EVA allows for the production of physically consistent forcing for historic and hypothetical eruptions of varying magnitude, source latitude, and season. Within CMIP6, EVA will be used to reconstruct volcanic forcing over the past 2000 years for use in the Paleo-Modeling Intercomparison Project (PMIP), and will provide forcing sets for VolMIP experiments aiming to quantify model uncertainty in the response to volcanic forcing. Here, the functional form of EVA will be introduced, along with illustrative examples including the EVA-based reconstruction of volcanic forcing over the historical period, and that of the 1815 Tambora eruption.

  13. A case study of aerosol depletion in a biomass burning plume over Eastern Canada during the 2011 BORTAS field experiment

    NASA Astrophysics Data System (ADS)

    Franklin, J. E.; Drummond, J. R.; Griffin, D.; Pierce, J. R.; Waugh, D. L.; Palmer, P. I.; Parrington, M.; Lee, J. D.; Lewis, A. C.; Rickard, A. R.; Taylor, J. W.; Allan, J. D.; Coe, H.; Walker, K. A.; Chisholm, L.; Duck, T. J.; Hopper, J. T.; Blanchard, Y.; Gibson, M. D.; Curry, K. R.; Sakamoto, K. M.; Lesins, G.; Dan, L.; Kliever, J.; Saha, A.

    2014-02-01

    We present measurements of a long range smoke transport event recorded on 20-21 July 2011 over Halifax, Nova Scotia, Canada, during the Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS-B) campaign. Ground-based Fourier transform spectrometers and photometers detected air masses associated with large wildland fires burning in eastern Manitoba and western Ontario. We investigate a plume with high trace gas amounts but low amounts of particles that preceded and overlapped at the Halifax site with a second plume with high trace gas loadings and significant amounts of particulate material. We show that the first plume experienced a meteorological scavenging event but the second plume had not been similarly scavenged. This points to the necessity to account carefully for the plume history when considering long range transport since simultaneous or near-simultaneous times of arrival are not necessarily indicative of either similar trajectories or meteorological history. We investigate the origin of the scavenged plume, and the possibility of an aerosol wet deposition event occurring in the plume ~24 h prior to the measurements over Halifax. The region of lofting and scavenging is only monitored on an intermittent basis by the present observing network, and thus we must consider many different pieces of evidence in an effort to understand the early dynamics of the plume. Through this discussion we also demonstrate the value of having many simultaneous remote-sensing measurements in order to understand the physical and chemical behaviour of biomass burning plumes.

  14. A case study of aerosol scavenging in a biomass burning plume over eastern Canada during the 2011 BORTAS field experiment

    NASA Astrophysics Data System (ADS)

    Franklin, J. E.; Drummond, J. R.; Griffin, D.; Pierce, J. R.; Waugh, D. L.; Palmer, P. I.; Parrington, M.; Lee, J. D.; Lewis, A. C.; Rickard, A. R.; Taylor, J. W.; Allan, J. D.; Coe, H.; Walker, K. A.; Chisholm, L.; Duck, T. J.; Hopper, J. T.; Blanchard, Y.; Gibson, M. D.; Curry, K. R.; Sakamoto, K. M.; Lesins, G.; Dan, L.; Kliever, J.; Saha, A.

    2014-08-01

    We present measurements of a long-range smoke transport event recorded on 20-21 July 2011 over Halifax, Nova Scotia, Canada, during the Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS-B) campaign. Ground-based Fourier transform spectrometers and photometers detected air masses associated with large wildland fires burning in eastern Manitoba and western Ontario. We investigate a plume with high trace gas amounts but low amounts of particles that preceded and overlapped at the Halifax site with a second plume with high trace gas loadings and significant amounts of particulate material. We show that the first plume experienced a meteorological scavenging event, but the second plume had not been similarly scavenged. This points to the necessity to account carefully for the plume history when considering long-range transport since simultaneous or near-simultaneous times of arrival are not necessarily indicative of either similar trajectories or meteorological history. We investigate the origin of the scavenged plume, and the possibility of an aerosol wet deposition event occurring in the plume ~ 24 h prior to the measurements over Halifax. The region of lofting and scavenging is only monitored on an intermittent basis by the present observing network, and thus we must consider many different pieces of evidence in an effort to understand the early dynamics of the plume. Through this discussion we also demonstrate the value of having many simultaneous remote-sensing measurements in order to understand the physical and chemical behaviour of biomass burning plumes.

  15. Aerosol generation by raindrop impact on soil

    NASA Astrophysics Data System (ADS)

    Joung, Young Soo; Buie, Cullen R.

    2015-01-01

    Aerosols are investigated because of their significant impact on the environment and human health. To date, windblown dust and sea salt from sea spray through bursting bubbles have been considered the chief mechanisms of environmental aerosol dispersion. Here we investigate aerosol generation from droplets hitting wettable porous surfaces including various classifications of soil. We demonstrate that droplets can release aerosols when they influence porous surfaces, and these aerosols can deliver elements of the porous medium to the environment. Experiments on various porous media including soil and engineering materials reveal that knowledge of the surface properties and impact conditions can be used to predict when frenzied aerosol generation will occur. This study highlights new phenomena associated with droplets on porous media that could have implications for the investigation of aerosol generation in the environment.

  16. Aerosol generation by raindrop impact on soil.

    PubMed

    Joung, Young Soo; Buie, Cullen R

    2015-01-01

    Aerosols are investigated because of their significant impact on the environment and human health. To date, windblown dust and sea salt from sea spray through bursting bubbles have been considered the chief mechanisms of environmental aerosol dispersion. Here we investigate aerosol generation from droplets hitting wettable porous surfaces including various classifications of soil. We demonstrate that droplets can release aerosols when they influence porous surfaces, and these aerosols can deliver elements of the porous medium to the environment. Experiments on various porous media including soil and engineering materials reveal that knowledge of the surface properties and impact conditions can be used to predict when frenzied aerosol generation will occur. This study highlights new phenomena associated with droplets on porous media that could have implications for the investigation of aerosol generation in the environment.

  17. Stratospheric Aerosol Measurements

    NASA Technical Reports Server (NTRS)

    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

  18. Influence of continental advection on aerosol characteristics over Bay of Bengal (BoB) in winter: results from W-ICARB cruise experiment

    NASA Astrophysics Data System (ADS)

    Kharol, S. K.; Badarinath, K. V. S.; Kaskaoutis, D. G.; Sharma, A. R.; Gharai, B.

    2011-08-01

    The transport of aerosols and pollutants from continental India to the adjoining oceanic areas is a major topic of concern and several experimental campaigns have been conducted over the region focusing on aerosol characteristics and their climate implications. The present study analyzes the spectral aerosol optical depth (AOD) variations over Bay of Bengal (BoB) during Winter-Integrated Campaign for Aerosols, gases and Radiation Budget (W-ICARB) from 27 December 2008 to 30 January 2009 and investigates the influence of the adjoining landmass to the marine aerosol field. High AOD500 values (>0.7) occurred over northern BoB due to outflow of aerosols and pollutants from the densely populated Indo-Gangetic Plains (IGP); low AOD500 (0.1-0.2) was observed in central and southern BoB, far away from the mainland. The Angstrom exponent "α" was observed to be high (>1.2) near coastal waters, indicating relative abundance of accumulation-mode continental aerosols. On the other hand, over southern BoB its values dropped below ~0.7. National Center for Environmental Prediction (NCEP) reanalysis data on winds at 850 and 700 hPa, along with air-mass trajectories calculated using Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, suggested transport of continental aerosols from central and northern India over the BoB. On the other hand, when the ship was crossing the eastern BoB, the aerosol loading was strongly affected by air-masses originating from Southeast Asia, causing an increase in AOD and α. Biomass-burning episodes over the region played an important role in the observed aerosol properties. Terra/Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) AOD550 and cruise measured AOD550 showed good agreement (R2 = 0.86 and 0.77, respectively) over BoB, exhibiting similar AOD and α spatio-temporal variation.

  19. [Aerosol therapy].

    PubMed

    Wildhaber, J H

    1998-08-15

    Aerosol therapy plays a major role in the diagnosis and treatment of various lung diseases. The aim of inhalation therapy is to deposit a reproducible and adequate dose of a specific drug to the airways, in order to achieve a high, local, clinical effect while avoiding serious systemic side effects. To achieve this goal, it is therefore important to have an efficient inhalation device to deliver different medications. However, the currently available therapeutic inhalation devices (nebuliser, pressurised metered-dose inhaler and dry powder inhaler) are not very efficient in aerosol delivery and have several disadvantages. Inhalation devices can be assessed by in vitro studies, filter studies and radiolabelled deposition studies. Several radiolabelled deposition studies have shown that nebulisers and pressurised metered-dose inhalers are not very efficient in aerosol delivery. In children, before 1997, only 0.5% to 15% of the total nebulised or actuated dose from a nebuliser or pressurised metered-dose inhaler actually reached the lungs. These numbers were somewhat improved in adults, 30% of the total nebulised or actuated dose reaching the airways. Aerosol therapy with dry powder inhalers was the most efficient before 1997, 30% of the total dose being deposited in the lungs of adults and children. In 1997, new developments in pressurised metered-dose inhalers much improved their efficiency in aerosol delivery. Lung deposition can be increased by up to 60% with use of a non-electrostatic holding chamber and/or a pressurised metered-dose inhaler with a hydrofluoroalkane propellant possessing superior aerosol characteristics. Several studies comparing the clinical efficiency of different inhalation devices have shown that the choice of an optimal inhalation device is crucial. In addition to the aerosol characteristics, ventilation parameters and airway morphology have an important bearing on deposition patterns. These parameters may be greatly influenced by the

  20. AEROSOL CHEMICAL CHARACTERISTION ON BOARD THE DOE G1 AIRCRAFT USING A PARTICLE INTO LIQUID SAMPLER DURING THE TEXAQS 2000 EXPERIMENT.

    SciTech Connect

    LEE,Y.N.; SONG,Z.; LIU,Y.; DAUM,P.; WEBER,R.; ORSINI,D.; LAULAINEN,N.; HUBBE,J.; MORRIS,V.

    2001-01-13

    Knowledge of aerosol chemical composition is key to understanding a number of properties of ambient aerosol particles including sources, size/number distribution, chemical evolution, optical properties and human health effects. Although filter based techniques have been widely used to determine aerosol chemical constituents, they generally cannot provide sufficiently fast time resolution needed to investigate sources and chemical evolution that effect aerosol chemical, size and number changes. In order to gain an ability to describe and predict the life cycles of ambient aerosols as a basis for ambient air quality control, fast and sensitive determination of the aerosol chemical composition must be made available. To help to achieve this goal, we deployed a newly developed technique, referred to as PILS (particle-into-liquid-sampler), on the DOE G1 aircraft during the 2000 Texas Air Quality Study (TexAQS 2000) to characterize the major ionic species of aerosol particles with aerodynamic size smaller than 2.5 {micro}m (PM 2.5). The results obtained are examined in the context of other simultaneously collected data for insights into the measurement capability of the PILS system.

  1. The evaluation of a shuttle borne lidar experiment to measure the global distribution of aerosols and their effect on the atmospheric heat budget

    NASA Technical Reports Server (NTRS)

    Shipley, S. T.; Joseph, J. H.; Trauger, J. T.; Guetter, P. J.; Eloranta, E. W.; Lawler, J. E.; Wiscombe, W. J.; Odell, A. P.; Roesler, F. L.; Weinman, J. A.

    1975-01-01

    A shuttle-borne lidar system is described, which will provide basic data about aerosol distributions for developing climatological models. Topics discussed include: (1) present knowledge of the physical characteristics of desert aerosols and the absorption characteristics of atmospheric gas, (2) radiative heating computations, and (3) general circulation models. The characteristics of a shuttle-borne radar are presented along with some laboratory studies which identify schemes that permit the implementation of a high spectral resolution lidar system.

  2. A satellite view of aerosols in the climate system

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram J.; Tanre, Didier; Boucher, Olivier

    2002-01-01

    Anthropogenic aerosols are intricately linked to the climate system and to the hydrologic cycle. The net effect of aerosols is to cool the climate system by reflecting sunlight. Depending on their composition, aerosols can also absorb sunlight in the atmosphere, further cooling the surface but warming the atmosphere in the process. These effects of aerosols on the temperature profile, along with the role of aerosols as cloud condensation nuclei, impact the hydrologic cycle, through changes in cloud cover, cloud properties and precipitation. Unravelling these feedbacks is particularly difficult because aerosols take a multitude of shapes and forms, ranging from desert dust to urban pollution, and because aerosol concentrations vary strongly over time and space. To accurately study aerosol distribution and composition therefore requires continuous observations from satellites, networks of ground-based instruments and dedicated field experiments. Increases in aerosol concentration and changes in their composition, driven by industrialization and an expanding population, may adversely affect the Earth's climate and water supply.

  3. Toxicity of atmospheric aerosols on marine phytoplankton

    USGS Publications Warehouse

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

    2009-01-01

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

  4. A global aerosol classification algorithm incorporating multiple satellite data sets of aerosol and trace gas abundances

    NASA Astrophysics Data System (ADS)

    Penning de Vries, M. J. M.; Beirle, S.; Hörmann, C.; Kaiser, J. W.; Stammes, P.; Tilstra, L. G.; Tuinder, O. N. E.; Wagner, T.

    2015-09-01

    Detecting the optical properties of aerosols using passive satellite-borne measurements alone is a difficult task due to the broadband effect of aerosols on the measured spectra and the influences of surface and cloud reflection. We present another approach to determine aerosol type, namely by studying the relationship of aerosol optical depth (AOD) with trace gas abundance, aerosol absorption, and mean aerosol size. Our new Global Aerosol Classification Algorithm, GACA, examines relationships between aerosol properties (AOD and extinction Ångström exponent from the Moderate Resolution Imaging Spectroradiometer (MODIS), UV Aerosol Index from the second Global Ozone Monitoring Experiment, GOME-2) and trace gas column densities (NO2, HCHO, SO2 from GOME-2, and CO from MOPITT, the Measurements of Pollution in the Troposphere instrument) on a monthly mean basis. First, aerosol types are separated based on size (Ångström exponent) and absorption (UV Aerosol Index), then the dominating sources are identified based on mean trace gas columns and their correlation with AOD. In this way, global maps of dominant aerosol type and main source type are constructed for each season and compared with maps of aerosol composition from the global MACC (Monitoring Atmospheric Composition and Climate) model. Although GACA cannot correctly characterize transported or mixed aerosols, GACA and MACC show good agreement regarding the global seasonal cycle, particularly for urban/industrial aerosols. The seasonal cycles of both aerosol type and source are also studied in more detail for selected 5° × 5° regions. Again, good agreement between GACA and MACC is found for all regions, but some systematic differences become apparent: the variability of aerosol composition (yearly and/or seasonal) is often not well captured by MACC, the amount of mineral dust outside of the dust belt appears to be overestimated, and the abundance of secondary organic aerosols is underestimated in comparison

  5. Satellite Remote Sensing: Aerosol Measurements

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph A.

    2013-01-01

    Aerosols are solid or liquid particles suspended in the air, and those observed by satellite remote sensing are typically between about 0.05 and 10 microns in size. (Note that in traditional aerosol science, the term "aerosol" refers to both the particles and the medium in which they reside, whereas for remote sensing, the term commonly refers to the particles only. In this article, we adopt the remote-sensing definition.) They originate from a great diversity of sources, such as wildfires, volcanoes, soils and desert sands, breaking waves, natural biological activity, agricultural burning, cement production, and fossil fuel combustion. They typically remain in the atmosphere from several days to a week or more, and some travel great distances before returning to Earth's surface via gravitational settling or washout by precipitation. Many aerosol sources exhibit strong seasonal variability, and most experience inter-annual fluctuations. As such, the frequent, global coverage that space-based aerosol remote-sensing instruments can provide is making increasingly important contributions to regional and larger-scale aerosol studies.

  6. Genesis of elevated aerosol loading over the Indian region

    NASA Astrophysics Data System (ADS)

    Prijith, S. S.; Rao, P. V. N.; Mohan, Mannil

    2016-05-01

    Elevated aerosols assume importance as the diabatic heating due to aerosol absorption is more intense at higher altitudes where the atmosphere becomes thinner. Indian region, especially its central and northern latitudes, experiences significant loading of elevated aerosols during pre-monsoon and summer months. Genesis of elevated aerosol loading over Indian region is investigated in the present study, using multi-year satellite observations from Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) and Moderate Resolution Imaging Spectroradiometer (MODIS) along with reanalysis winds from MERRA. Central India is observed to have prominent aerosols loading at higher altitudes during pre-monsoon season, whereas it is during summer months over north-west India. Further analysis reveals that the elevated aerosols over Indian region in pre-monsoon and summer months are significantly contributed by transported mineral dust from the arid continental regions at west. In addition to the mineral dust advection, aerosols at higher altitudes over Indian region are enriched by strong convection and associated vertical transport of surface level aerosols. Vertical transport of aerosols observed over Indian region during pre-monsoon and summer months is aided by intense convergence at the surface level and divergence at the upper level. Moreover, aerosol source/sink strength estimated using aerosol flux continuity equation show significant aerosol production over central India during pre-monsoon. Strong vertical transport prevails during pre-monsoon uplifts the locally produced aerosols, with considerable anthropogenic fraction, to higher altitudes where their impacts would be more intense.

  7. Toward Creating A Global Retrospective Climatology of Aerosol Properties

    NASA Technical Reports Server (NTRS)

    Curran, Robert J.; Mishchenko, Michael I.; Hansen, James E. (Technical Monitor)

    2000-01-01

    Tropospheric aerosols are thought to cause a significant direct and indirect climate forcing, but the magnitude of this forcing remains highly uncertain because of poor knowledge of global aerosol characteristics and their temporal changes. The standard long-term global product, the one-channel Advanced Very-High-Resolution Radiometer (AVHRR) aerosol optical thickness over the ocean, relies on a single predefined aerosol model and can be inaccurate in many cases. Furthermore, it provides no information on aerosol column number density, thus making it impossible to estimate the indirect aerosol effect on climate. Total Ozone Mapping Spectrometer (TOMS) data can be used to detect absorbing aerosols over land, but are insensitive to aerosols located below one kilometer. It is thus clear that innovative approaches must be employed in order to extract a more quantitative and accurate aerosol climatology from available satellite and other measurements, thus enabling more reliable estimates of the direct and indirect aerosol forcings. The Global Aerosol Climatology Project (GACP) was established in 1998 as part of the Global Energy and Water Cycle Experiment (GEWEX). Its main objective is to analyze satellite radiance measurements and field observations to infer the global distribution of aerosols, their properties, and their seasonal and interannual variations. The overall goal is to develop advanced global aerosol climatologies for the period of satellite data and to make the aerosol climatologies broadly available through the GACP web site.

  8. SECONDARY ORGANIC AEROSOL FORMATION FROM THE OXIDATION OF AROMATIC HYDROCARBONS IN THE PRESENCE OF DRY SUBMICRON AMMONIUM SULFATE AEROSOL

    EPA Science Inventory

    A laboratory study was conducted to examine formation of secondary organic aerosols. A smog chamber system was developed for studying gas-aerosol interactions in a dynamic flow reactor. These experiments were conducted to investigate the fate of gas and aerosol phase compounds ...

  9. [The institutional promotion of good practices in the operational management of health and safety: the experience of Italy Crown Aerosols on the monitoring of behavior].

    PubMed

    de Merich, D; Pellicci, M; Serignoli, R

    2010-01-01

    Within the intelligence support and training to small and medium-sized enterprises (SMEs) and promoting a culture of health and safety at work, ISPESL is engaged on two fundamental pillars of activity: Consolidation of the national surveillance system of injuries through the promotion of methods and tools for the reconstruction of the dynamics incidental identification of causal determinants, with the aim of improving the capabilities of risk assessment of systems to prevent corporate. The promotion of good working practices, as Focal Point of the European Health and Safety at Work in Bilbao, the goal is to support prevention activities by providing business application examples of measures for improvement (technical, organizational, procedural) made in the proposing firms and validated by a technical appraisal conducted by ISPESL. Among the methodologies and tools that can be made available to companies in the operational management of health and safety in work activities, the approach to analyze and evaluate the behavior implemented by all persons within the company (managers, employees, workers) is a the most innovative preventive strategies that can be implemented to correct any improper practices behavioral wrongly tolerated in everyday work practice. The experience of Crown Aerosol Italy, the program "STOP TO ACCIDENTS, 2009 Best Practices award in the competition on the theme" Risk Assessment ", aims to demonstrate how the application of a method for monitoring behavior at work, shared in its planning with all those business, has not only reached but would assist the organization has developed at an individual level greater awareness and sense of responsibility also to their colleagues, by promoting good working practices.

  10. Biological aerosol trigger

    NASA Astrophysics Data System (ADS)

    DeSha, Michael S.

    1999-01-01

    In recent history, manmade and natural events have shown us the every-present need for systems to monitor the troposphere for contaminates. These contaminants may take either a chemical or biological form, which determines the methods we use to monitor them. Monitoring the troposphere for biological contaminants is of particular interest to my organization. Whether manmade or natural, contaminants of a biological origin share similar constituents; typically the aromatic amino acids tryptophan, phenylalanine, and tyrosine. All of these proteinaceous compounds autofluorescence when exposed to UV radiation and this established the basis of the laser-induced fluorescence technique we use to detect biological contaminants. This technique can be employed in either point or remote detection schemes and is a valuable tool for discriminating proteinaceous form non-proteinaceous aerosols. For this particular presentation I am going to describe a breadboard point sensor we designed and fabricated to detect proteinaceous aerosols. Previous point sensor designs relied on convoluted flow paths to concentrate the aerosols into a solution. Other systems required precise beam alignment to evenly distribute the energy irradiating the detector elements. Our objective was to build a simple system where beam alignment is not critical, and the flow is straight and laminar. The breadboard system was developed over a nine- month period and its performance assessed at a recent test at Dugway Proving Grounds in Utah. In addition, we have performed chamber experiments in an attempt to establish a baseline for the systems. The results of these efforts are presented here.

  11. CCN activity of aliphatic amine secondary aerosol

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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

  12. Global Atmospheric Aerosol Modeling

    NASA Technical Reports Server (NTRS)

    Hendricks, Johannes; Aquila, Valentina; Righi, Mattia

    2012-01-01

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

  13. Aerosol Models for the CALIPSO Lidar Inversion Algorithms

    NASA Technical Reports Server (NTRS)

    Omar, Ali H.; Winker, David M.; Won, Jae-Gwang

    2003-01-01

    We use measurements and models to develop aerosol models for use in the inversion algorithms for the Cloud Aerosol Lidar and Imager Pathfinder Spaceborne Observations (CALIPSO). Radiance measurements and inversions of the AErosol RObotic NETwork (AERONET1, 2) are used to group global atmospheric aerosols using optical and microphysical parameters. This study uses more than 105 records of radiance measurements, aerosol size distributions, and complex refractive indices to generate the optical properties of the aerosol at more 200 sites worldwide. These properties together with the radiance measurements are then classified using classical clustering methods to group the sites according to the type of aerosol with the greatest frequency of occurrence at each site. Six significant clusters are identified: desert dust, biomass burning, urban industrial pollution, rural background, marine, and dirty pollution. Three of these are used in the CALIPSO aerosol models to characterize desert dust, biomass burning, and polluted continental aerosols. The CALIPSO aerosol model also uses the coarse mode of desert dust and the fine mode of biomass burning to build a polluted dust model. For marine aerosol, the CALIPSO aerosol model uses measurements from the SEAS experiment 3. In addition to categorizing the aerosol types, the cluster analysis provides all the column optical and microphysical properties for each cluster.

  14. A System to Create Stable Nanoparticle Aerosols from Nanopowders.

    PubMed

    Ding, Yaobo; Riediker, Michael

    2016-01-01

    Nanoparticle aerosols released from nanopowders in workplaces are associated with human exposure and health risks. We developed a novel system, requiring minimal amounts of test materials (min. 200 mg), for studying powder aerosolization behavior and aerosol properties. The aerosolization procedure follows the concept of the fluidized-bed process, but occurs in the modified volume of a V-shaped aerosol generator. The airborne particle number concentration is adjustable by controlling the air flow rate. The system supplied stable aerosol generation rates and particle size distributions over long periods (0.5-2 hr and possibly longer), which are important, for example, to study aerosol behavior, but also for toxicological studies. Strict adherence to the operating procedures during the aerosolization experiments ensures the generation of reproducible test results. The critical steps in the standard protocol are the preparation of the material and setup, and the aerosolization operations themselves. The system can be used for experiments requiring stable aerosol concentrations and may also be an alternative method for testing dustiness. The controlled aerosolization made possible with this setup occurs using energy inputs (may be characterized by aerosolization air velocity) that are within the ranges commonly found in occupational environments where nanomaterial powders are handled. This setup and its operating protocol are thus helpful for human exposure and risk assessment. PMID:27501179

  15. Aerosol gels

    NASA Technical Reports Server (NTRS)

    Sorensen, Christopher M. (Inventor); Chakrabarti, Amitabha (Inventor); Dhaubhadel, Rajan (Inventor); Gerving, Corey (Inventor)

    2010-01-01

    An improved process for the production of ultralow density, high specific surface area gel products is provided which comprises providing, in an enclosed chamber, a mixture made up of small particles of material suspended in gas; the particles are then caused to aggregate in the chamber to form ramified fractal aggregate gels. The particles should have a radius (a) of up to about 50 nm and the aerosol should have a volume fraction (f.sub.v) of at least 10.sup.-4. In preferred practice, the mixture is created by a spark-induced explosion of a precursor material (e.g., a hydrocarbon) and oxygen within the chamber. New compositions of matter are disclosed having densities below 3.0 mg/cc.

  16. Smog chamber experiments to investigate Henry's law constants of glyoxal using different seed aerosols as well as imidazole formation in the presence of ammonia

    NASA Astrophysics Data System (ADS)

    Jakob, Ronit

    2015-04-01

    Aerosols play an important role in the chemistry and physics of the atmosphere. Hence, they have a direct as well as an indirect impact on the earth's climate. Depending on their formation, one distinguishes between primary and secondary aerosols[1]. Important groups within the secondary aerosols are the secondary organic aerosols (SOAs). In order to improve predictions about these impacts on the earth's climate the existing models need to be optimized, because they still underestimate SOA formation[2]. Glyoxal, the smallest α-dicarbonyl, not only acts as a tracer for SOA formation but also as a direct contributor to SOA. Because glyoxal has such a high vapour pressure, it was common knowledge that it does not take part in gas-particle partitioning and therefore has no impact on direct SOA formation. However, the Henry's law constant for glyoxal is surprisingly high. This has been explained by the hydration of the aldehyde groups, which means that a species with a lower vapour pressure is produced. Therefore the distribution of glyoxal between gas- and particle phase is atmospherically relevant and the direct contribution of glyoxal to SOA can no longer be neglected[3]. Besides this particulate glyoxal is able to undergo heterogeneous chemistry with gaseous ammonia to form imidazoles. This plays an important role for regions with aerosols exhibiting alkaline pH values for example from lifestock or soil dust because imidazoles as nitrogen containing compounds change the optical properties of aerosols[4]. A high salt concentration present in chamber seed aerosols leads to an enhanced glyoxal uptake into the particle. This effect is called "salting-in". The salting effect depends on the composition of the seed aerosol as well as the soluble compound. For very polar compounds, like glyoxal, a "salting-in" is observed[3]. Glyoxal particle formation during a smog chamber campaign at Paul-Scherrer-Institut (PSI) in Switzerland was examined using different seed aerosols

  17. Lidar backscattering measurements of background stratospheric aerosols

    NASA Technical Reports Server (NTRS)

    Remsberg, E. E.; Northam, G. B.; Butler, C. F.

    1979-01-01

    A comparative lidar-dustsonde experiment was conducted in San Angelo, Texas, in May 1974 in order to estimate the uncertainties in stratospheric-aerosol backscatter for the NASA Langley 48-inch lidar system. The lidar calibration and data-analysis procedures are discussed. Results from the Texas experiment indicate random and systematic uncertainties of 35 and 63 percent, respectively, in backscatter from a background stratospheric-aerosol layer at 20 km.

  18. Effect of Aerosol and Ocean Representation on Simulated Climate Responses

    NASA Astrophysics Data System (ADS)

    Dallafior, Tanja; Folini, Doris; Knutti, Reto; Wild, Martin

    2016-04-01

    It is still debated to what extent anthropogenic aerosols shaped 20th century surface temperatures, especially sea surface temperatures (SSTs), through alteration of surface solar radiation (SSR). SSTs, in turn, are crucial in the context of atmospheric circulation and ocean heat uptake. Uncertainty considering anthropogenic aerosol forcing thus translates into uncertainty regarding ocean heat uptake and, ultimately, climate responses towards anthropogenic influences. We use the global climate model ECHAM to analyse the 20th century climate response towards either anthropogenic aerosols or well-mixed greenhouse gases or both with different representations of ocean and aerosols: atmosphere-only with prescribed SSTs and interactive aerosols; mixed-layer ocean and interactive or prescribed aerosols; fully coupled with prescribed aerosols. For interactive aerosols we use the Hamburg Aerosol Module (HAM). Our results suggest that up to 15% of global ocean surfaces undergo an SSR reduction of at least -4W/m² in the year 2000, due to anthropogenic aerosols. The area affected depends on how aerosols are represented and whether clear sky or all sky SSR is considered. In MLO equilibria with interactive aerosols, anthropogenic aerosols clearly shape surface temperature response patterns. This is to a lesser degree the case for the transient fully coupled case. Additivity of global mean temperature responses towards single forcings - an assumption often made in the literature - is not fulfilled for the MLO experiments, but for the fully coupled experiments. While some of these differences can be attributed to the differing ocean representation, it is implied that differing aerosol representation may play an even more relevant role. Thus, our results corroborate not only the relevance of anthropogenic aerosols for surface temperature responses, but also highlight the relevance of choice of aerosol representation.

  19. On the role of thermodynamics and cloud-aerosol-precipitation interactions over thunderstorm activity during GoAmazon and ACRIDICON-CHUVA field experiments

    NASA Astrophysics Data System (ADS)

    Albrecht, R. I.; Morales, C. A.; Hoeller, H.; Braga, R. C.; Machado, L.; Wendisch, M.; Andreae, M. O.; Rosenfeld, D.; Poeschl, U.; Biscaro, T.; Lima, W.; Eichholz, C.; Oliveira, R. A. J.; Sperling, V.; Carvalho, I.; Calheiros, A. J. P.; Amaral, L. F.; Cecchin, M.; Saraiva, J.; Saraiva, I.; Schumacher, C.; Funk, A. B.

    2015-12-01

    Based on satellite data, total (intracloud and cloud-to-ground) lightning activity climatological annual cycle over the GoAmazon area of interest (from T0 to T3 sites) shows that lightning activity is moderate (up to 10 flashes per day - fl day-1) throughout the wet (December-March) and dry (April-August) seasons, with T3 always being a little greater than T1 and T0 sites, respectively. During the dry-to-wet transition season (September-October), however, lightning activity peaks up to 25 fl day-1 at T1, followed by T3 (20 fl day-1) and T0 (15 fl day-1). The diurnal cycle reveals that the onset of deep convection during this same season starts one hour and peaks two hours earlier than the wet season. In the Amazon, cloud updrafts are primarily controlled by the local environment thermodynamics. During the dry-to-wet transition season, thermodynamics is significantly changed by land cover land cover where cloud base heights are elevated over deforested areas potentially increasing the strength of updrafts due to a better processing of the convective available potential energy, and therefore also increasing cloud electrification. The total (intracloud and cloud-to-ground) LIghtning NET(LINET - Nowcast) installed in September-October 2014 for GoAmazon IOP2 and ACRIDICON-CHUVA field experiments and the set of weather radars revealed that the thunderstorm enhancement over T1 (Manaus) during the dry-to-wet season is driven by the interaction between river breeze and the main easterly winds over Amazon basin, resulting in a locally forced convergent flow on the east side of Rio Negro which drives deep afternoon convection. In terms of atmospheric pollution, the dry-to-wet season is also marked by increased biomass burning, and the city of Manaus (T1) is a local polluted heat island. We will also present quantified thermodynamical and microphysical differences between the thunderstorms that developed over T0, T1 and T2. Our hypothesis is that cloud charge centers, total

  20. Aerosol typing - key information from aerosol studies

    NASA Astrophysics Data System (ADS)

    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

  1. Zero-gravity aerosol behavior

    NASA Technical Reports Server (NTRS)

    Edwards, H. W.

    1981-01-01

    The feasibility and scientific benefits of a zero gravity aerosol study in an orbiting laboratory were examined. A macroscopic model was devised to deal with the simultaneous effects of diffusion and coagulation of particles in the confined aerosol. An analytical solution was found by treating the particle coagulation and diffusion constants as ensemble parameters and employing a transformation of variables. The solution was used to carry out simulated zero gravity aerosol decay experiments in a compact cylindrical chamber. The results demonstrate that the limitations of physical space and time imposed by the orbital situation are not prohibitive in terms of observing the history of an aerosol confined under zero gravity conditions. While the absence of convective effects would be a definite benefit for the experiment, the mathematical complexity of the problem is not greatly reduced when the gravitational term drops out of the equation. Since the model does not deal directly with the evolution of the particle size distribution, it may be desirable to develop more detailed models before undertaking an orbital experiment.

  2. Global aerosol effects on convective clouds

    NASA Astrophysics Data System (ADS)

    Wagner, Till; Stier, Philip

    2013-04-01

    Atmospheric aerosols affect cloud properties, and thereby the radiation balance of the planet and the water cycle. The influence of aerosols on clouds is dominated by increase of cloud droplet and ice crystal numbers (CDNC/ICNC) due to enhanced aerosols acting as cloud condensation and ice nuclei. In deep convective clouds this increase in CDNC/ICNC is hypothesised to increase precipitation because of cloud invigoration through enhanced freezing and associated increased latent heat release caused by delayed warm rain formation. Satellite studies robustly show an increase of cloud top height (CTH) and precipitation with increasing aerosol optical depth (AOD, as proxy for aerosol amount). To represent aerosol effects and study their influence on convective clouds in the global climate aerosol model ECHAM-HAM, we substitute the standard convection parameterisation, which uses one mean convective cloud for each grid column, with the convective cloud field model (CCFM), which simulates a spectrum of convective clouds, each with distinct values of radius, mixing ratios, vertical velocity, height and en/detrainment. Aerosol activation and droplet nucleation in convective updrafts at cloud base is the primary driver for microphysical aerosol effects. To produce realistic estimates for vertical velocity at cloud base we use an entraining dry parcel sub cloud model which is triggered by perturbations of sensible and latent heat at the surface. Aerosol activation at cloud base is modelled with a mechanistic, Köhler theory based, scheme, which couples the aerosols to the convective microphysics. Comparison of relationships between CTH and AOD, and precipitation and AOD produced by this novel model and satellite based estimates show general agreement. Through model experiments and analysis of the model cloud processes we are able to investigate the main drivers for the relationship between CTH / precipitation and AOD.

  3. Aerosol Optical Extinction during the Front Range Air Pollution and Photochemistry Experiment (FRAPPE) 2014 Summertime Field Campaign, Colorado U.S.A.

    NASA Astrophysics Data System (ADS)

    Dingle, J. H.; Vu, K. K. T.; Bahreini, R.; Apel, E. C.; Campos, T. L.; Cantrell, C. A.; Cohen, R. C.; Ebben, C. J.; Flocke, F. M.; Fried, A.; Herndon, S. C.; Hills, A. J.; Hornbrook, R. S.; Huey, L. G.; Kaser, L.; Mauldin, L.; Montzka, D. D.; Nowak, J. B.; Richter, D.; Roscioli, J. R.; Shertz, S.; Stell, M. H.; Tanner, D.; Tyndall, G. S.; Walega, J.; Weibring, P.; Weinheimer, A. J.

    2015-12-01

    Aerosol optical extinction (βext) was measured in the Colorado Front Range Denver Metropolitan Area as part of the summertime air quality airborne field campaign to characterize the influence of sources, photochemical processing, and transport of pollution on local air quality. An Aerodyne Cavity Attenuated Phase Shift particle light extinction monitor (CAPS-PMex) was deployed to measure dry βext at λ=632 nm at 1 Hz. Data from a suite of gas-phase instrumentation were used to interpret the βext under various categories of aged air masses and sources. Extinction enhancement ratios of Δβext/ΔCO were evaluated under 3 differently aged air mass categories (fresh, intermediately aged, and aged) to investigate impacts of photochemistry on βext. Δβext/ΔCO was significantly increased in heavily aged air masses compared to fresh air masses (0.17 Mm-1/ppbv and 0.094 Mm-1/ppbv respectively). The resulting increase in Δβext/ΔCO under heavily aged air masses was represented by secondary organic aerosols (SOA) formation. Aerosol composition and sources from urban, natural oil and gas wells (OG), and agriculture and livestock operations were also evaluated for their impacts on βext. Linear regression fits to βext vs. organic aerosol mass showed higher correlation coefficients under the urban and OG plumes (r=0.55 and r=0.71 respectively) and weakest under agricultural and livestock plumes (r=0.28). The correlation between βext and nitrate aerosol mass however was best under the agriculture and livestock plumes (r=0.81), followed by OG plumes (r=0.74), suggesting co-location of aerosol nitrate precursor sources with OG emissions. Finally, non-refractory mass extinction efficiency (MEE) was analyzed. MEE was observed to be 1.37 g/m2 and 1.30 g/m2 in OG and urban+OG plumes, respectively.

  4. Aerosol Characterization Data from the Asian Pacific Regional Aerosol Characterization Project (ACE-Asia)

    DOE Data Explorer

    The Aerosol Characterization Experiments (ACE) were designed to increase understanding of how atmospheric aerosol particles affect the Earth's climate system. These experiments integrated in-situ measurements, satellite observations, and models to reduce the uncertainty in calculations of the climate forcing due to aerosol particles and improve the ability of models to predict the influences of aerosols on the Earth's radiation balance. ACE-Asia was the fourth in a series of experiments organized by the International Global Atmospheric Chemistry (IGAC) Program (A Core Project of the International Geosphere Biosphere Program). The Intensive Field Phase for ACE-Asia took place during the spring of 2001 (mid-March through early May) off the coast of China, Japan and Korea. ACE-Asia pursued three specific objectives: 1) Determine the physical, chemical, and radiative properties of the major aerosol types in the Eastern Asia and Northwest Pacific region and investigate the relationships among these properties. 2) Quantify the physical and chemical processes controlling the evolution of the major aerosol types and in particular their physical, chemical, and radiative properties. 3) Develop procedures to extrapolate aerosol properties and processes from local to regional and global scales, and assess the regional direct and indirect radiative forcing by aerosols in the Eastern Asia and Northwest Pacific region [Edited and shortened version of summary at http://data.eol.ucar.edu/codiac/projs?ACE-ASIA]. The Ace-Asia collection contains 174 datasets.

  5. Inference of stratospheric aerosol composition and size distribution from SAGE II satellite measurements

    NASA Technical Reports Server (NTRS)

    Wang, Pi-Huan; Mccormick, M. P.; Fuller, W. H.; Yue, G. K.; Swissler, T. J.; Osborn, M. T.

    1989-01-01

    A method for inferring stratospheric aerosol composition and size distribution from the water vapor concentration and aerosol extinction measurements obtained in the Stratospheric Aerosol and Gas Experiment (SAGE) II and the associated temperature from the NMC. The aerosols are assumed to be sulfuric acid-water droplets. A modified Levenberg-Marquardt algorithm is used to determine model size distribution parameters based on the SAGE II multiwavelength aerosol extinctions. It is found that the best aerosol size information is contained in the aerosol radius range between about 0.25 and 0.80 micron.

  6. Chemical properties and outflow patterns of anthropogenic and dust particles on Rishiri Island during the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia)

    NASA Astrophysics Data System (ADS)

    Matsumoto, Kiyoshi; Uyama, Yukiko; Hayano, Teruaki; Tanimoto, Hiroshi; Uno, Itsushi; Uematsu, Mitsuo

    2003-12-01

    Investigations of chemical properties and transport mechanisms of continental aerosols are necessary for estimating their influences on global radiative budget and on the global material cycle. Intensive measurements of atmospheric aerosols and the associated species on Rishiri Island, near the northern tip of Japan, were conducted from March to May 2001, in order to understand the chemical properties, source regions, transport pathways, and transport patterns of anthropogenic and mineral aerosols over the east Asian Pacific Rim region during the spring. Mean concentrations of nss-SO42-, NO3-, NH4+, nss-Ca2+ in aerosols were 2.48, 0.64, 0.72, and 0.17 μg m-3, respectively. Elemental carbon and organic carbon in fine particles (d < 2.5 μm) yielded mean concentrations of 0.25 and 0.80 μg m-3, respectively. The concentrations of these species frequently increased to higher values because of outbreaks of continental polluted air masses, whereas under background conditions, they decreased to lower values similar to those observed over the remote ocean. Our results demonstrate that nss-SO42- and NH4+ coexist in fine particles, that NO3- and nss-Ca2+ coexist in coarse particles, and that each set is transported in an alternate manner. Continentally derived NO3- is transported as coarse particle to the east Asian Pacific Rim region. Anthropogenic pollutants and dust particles are not necessarily transported together. It was often found that anthropogenic fine particles containing abundant nss-SO42- appeared first and were then followed by large mineral particles that had absorbed NO3-. Short-term intrusion of the air masses containing abundant particulate carbonaceous compounds, probably due to the influence of biomass burning, also often occurred during the outflow events of continental air masses. Atmospheric behaviors of sulfate, nitrate, and carbonaceous species are different from one another, although they are all derived mainly from combustion processes.

  7. Atmospheric responses to the redistribution of anthropogenic aerosols

    NASA Astrophysics Data System (ADS)

    Wang, Yuan; Jiang, Jonathan H.; Su, Hui

    2015-09-01

    The geographical shift of global anthropogenic aerosols from the developed countries to the Asian continent since the 1980s could potentially perturb the regional and global climate due to aerosol-cloud-radiation interactions. We use an atmospheric general circulation model with different aerosol scenarios to investigate the radiative and microphysical effects of anthropogenic aerosols from different regions on the radiation budget, precipitation, and large-scale circulations. An experiment contrasting anthropogenic aerosol scenarios in 1970 and 2010 shows that the altered cloud reflectivity and solar extinction by aerosols results in regional surface temperature cooling in East and South Asia, and warming in the US and Europe, respectively. These aerosol-induced temperature changes are consistent with the relative temperature trends from 1980 to 2010 over different regions in the reanalysis data. A reduced meridional streamfunction and zonal winds over the tropics as well as a poleward shift of the jet stream suggest weakened and expanded tropical circulations, which are induced by the redistributed aerosols through a relaxing of the meridional temperature gradient. Consequently, precipitation is suppressed in the deep tropics and enhanced in the subtropics. Our assessments of the aerosol effects over the different regions suggest that the increasing Asian pollution accounts for the weakening of the tropics circulation, while the decreasing pollution in Europe and US tends to shift the circulation systems southward. Moreover, the aerosol indirect forcing is predominant over the total aerosol forcing in magnitude, while aerosol radiative and microphysical effects jointly shape the meridional energy distributions and modulate the circulation systems.

  8. Aerosol mobility size spectrometer

    DOEpatents

    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.

  9. AEROSOL AND GAS MEASUREMENT

    EPA Science Inventory

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

  10. Aerosols and environmental pollution

    NASA Astrophysics Data System (ADS)

    Colbeck, Ian; Lazaridis, Mihalis

    2010-02-01

    The number of publications on atmospheric aerosols has dramatically increased in recent years. This review, predominantly from a European perspective, summarizes the current state of knowledge of the role played by aerosols in environmental pollution and, in addition, highlights gaps in our current knowledge. Aerosol particles are ubiquitous in the Earth’s atmosphere and are central to many environmental issues; ranging from the Earth’s radiative budget to human health. Aerosol size distribution and chemical composition are crucial parameters that determine their dynamics in the atmosphere. Sources of aerosols are both anthropogenic and natural ranging from vehicular emissions to dust resuspension. Ambient concentrations of aerosols are elevated in urban areas with lower values at rural sites. A comprehensive understanding of aerosol ambient characteristics requires a combination of measurements and modeling tools. Legislation for ambient aerosols has been introduced at national and international levels aiming to protect human health and the environment.

  11. Aerosols and environmental pollution.

    PubMed

    Colbeck, Ian; Lazaridis, Mihalis

    2010-02-01

    The number of publications on atmospheric aerosols has dramatically increased in recent years. This review, predominantly from a European perspective, summarizes the current state of knowledge of the role played by aerosols in environmental pollution and, in addition, highlights gaps in our current knowledge. Aerosol particles are ubiquitous in the Earth's atmosphere and are central to many environmental issues; ranging from the Earth's radiative budget to human health. Aerosol size distribution and chemical composition are crucial parameters that determine their dynamics in the atmosphere. Sources of aerosols are both anthropogenic and natural ranging from vehicular emissions to dust resuspension. Ambient concentrations of aerosols are elevated in urban areas with lower values at rural sites. A comprehensive understanding of aerosol ambient characteristics requires a combination of measurements and modeling tools. Legislation for ambient aerosols has been introduced at national and international levels aiming to protect human health and the environment.

  12. Results from the Portable Infrared Aerosol Transmission Experiment (PIRATE) - Caribbean: An examination of the column integrated infrared extinction of Saharan dust and comparisons with data commonly used in models

    NASA Astrophysics Data System (ADS)

    Thomas, M.; Gautier, C.

    2004-12-01

    Infrared optical depth of Saharan dust from field measurements made in Puerto Rico are presented and compared with frequently-used dust models. The Portable Infrared Aerosol Transmission Experiment (PIRATE) - Caribbean was a ground-based experiment that measured the infrared transmission of transportted dust from the Saharan Desert. A Fourier Transform Infrared (FTIR) spectrometer was used in Boqueron, Puerto Rico from June 23 through June 30, 2004 as a high-resolution infrared sun photometer. The visible aerosol optical depth (AOD) around the time of each FTIR measurement was taken from a nearby AERONET sensor at La Parguera, Puerto Rico, for reference. The FTIR recorded the direct solar and scattered radiances from 3 to 14 microns. By collecting the solar radiance for several days, some for which the AOD was either very low (<0.1) or high (>0.5), the infrared AOD of the dust was determined as a function of wavelength. The measured infrared AOD of the dust is compared with frequently-used dust models, i.e. Volz and Sokolik, for various effective radii and assumed dust compositions. Since Saharan dust is often pervasive over large regions of the globe, these results are potentially important in models and satellite measurements attempting to determine the regional forcing from dust.

  13. Polar organic marker compounds in atmospheric aerosols during the LBA-SMOCC 2002 biomass burning experiment in Rondônia, Brazil: sources and source processes, time series, diel variations and size distributions

    NASA Astrophysics Data System (ADS)

    Claeys, M.; Kourtchev, I.; Pashynska, V.; Vas, G.; Vermeylen, R.; Wang, W.; Cafmeyer, J.; Chi, X.; Artaxo, P.; Andreae, M. O.; Maenhaut, W.

    2010-10-01

    Measurements of polar organic marker compounds were performed on aerosols that were collected at a pasture site in the Amazon basin (Rondônia, Brazil) using a high-volume dichotomous sampler (HVDS) and a Micro-Orifice Uniform Deposit Impactor (MOUDI) within the framework of the 2002 LBA-SMOCC (Large-Scale Biosphere Atmosphere Experiment in Amazônia - Smoke Aerosols, Clouds, Rainfall, and Climate: Aerosols From Biomass Burning Perturb Global and Regional Climate) campaign. The campaign spanned the late dry season (biomass burning), a transition period, and the onset of the wet season (clean conditions). In the present study a more detailed discussion is presented compared to previous reports on the behavior of selected polar marker compounds, including levoglucosan, malic acid, isoprene secondary organic aerosol (SOA) tracers and tracers for fungal spores. The tracer data are discussed taking into account new insights that recently became available into their stability and/or aerosol formation processes. During all three periods, levoglucosan was the most dominant identified organic species in the PM2.5 size fraction of the HVDS samples. In the dry period levoglucosan reached concentrations of up to 7.5 μg m-3 and exhibited diel variations with a nighttime prevalence. It was closely associated with the PM mass in the size-segregated samples and was mainly present in the fine mode, except during the wet period where it peaked in the coarse mode. Isoprene SOA tracers showed an average concentration of 250 ng m-3 during the dry period versus 157 ng m-3 during the transition period and 52 ng m-3 during the wet period. Malic acid and the 2-methyltetrols exhibited a different size distribution pattern, which is consistent with different aerosol formation processes (i.e., gas-to-particle partitioning in the case of malic acid and heterogeneous formation from gas-phase precursors in the case of the 2-methyltetrols). The 2-methyltetrols were mainly associated with the

  14. Aerosol physical properties from satellite horizon inversion

    NASA Technical Reports Server (NTRS)

    Gray, C. R.; Malchow, H. L.; Merritt, D. C.; Var, R. E.; Whitney, C. K.

    1973-01-01

    The feasibility is investigated of determining the physical properties of aerosols globally in the altitude region of 10 to 100 km from a satellite horizon scanning experiment. The investigation utilizes a horizon inversion technique previously developed and extended. Aerosol physical properties such as number density, size distribution, and the real and imaginary components of the index of refraction are demonstrated to be invertible in the aerosol size ranges (0.01-0.1 microns), (0.1-1.0 microns), (1.0-10 microns). Extensions of previously developed radiative transfer models and recursive inversion algorithms are displayed.

  15. Aerosol distribution apparatus

    DOEpatents

    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.

  16. Improved solid aerosol generator

    DOEpatents

    Prescott, D.S.; Schober, R.K.; Beller, J.

    1988-07-19

    An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates. 2 figs.

  17. Solid aerosol generator

    DOEpatents

    Prescott, Donald S.; Schober, Robert K.; Beller, John

    1992-01-01

    An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates.

  18. Solid aerosol generator

    DOEpatents

    Prescott, D.S.; Schober, R.K.; Beller, J.

    1992-03-17

    An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration is disclosed. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates. 2 figs.

  19. Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds

    SciTech Connect

    Turner, David, D.; Ferrare, Richard, A.

    2011-07-06

    The 'Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds' project focused extensively on the analysis and utilization of water vapor and aerosol profiles derived from the ARM Raman lidar at the Southern Great Plains ARM site. A wide range of different tasks were performed during this project, all of which improved quality of the data products derived from the lidar or advanced the understanding of atmospheric processes over the site. These activities included: upgrading the Raman lidar to improve its sensitivity; participating in field experiments to validate the lidar aerosol and water vapor retrievals; using the lidar aerosol profiles to evaluate the accuracy of the vertical distribution of aerosols in global aerosol model simulations; examining the correlation between relative humidity and aerosol extinction, and how these change, due to horizontal distance away from cumulus clouds; inferring boundary layer turbulence structure in convective boundary layers from the high-time-resolution lidar water vapor measurements; retrieving cumulus entrainment rates in boundary layer cumulus clouds; and participating in a field experiment that provided data to help validate both the entrainment rate retrievals and the turbulent profiles derived from lidar observations.

  20. CALIPSO Observations of Volcanic Aerosol in the Stratosphere

    NASA Technical Reports Server (NTRS)

    Thomason, Larry W.; Pitts, Michael C.

    2008-01-01

    In the stratosphere, the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) has observed the presence of aerosol plumes associated with the eruptions several volcanoes including Montserrat (May 2006), Chaiten (May 2008), and Kasatochi (August 2008). While the dense ash plumes from these eruptions dissipate relatively quickly, CALIPSO continued to detect an enhanced aerosol layer from the Montserrat eruption from the initial observations in June 2006 well into 2008. Solar occultation missions were uniquely capable of monitoring stratospheric aerosol. However, since the end of long-lived instruments like the Stratospheric Aerosol and Gas Experiment (SAGE II), there has been no clear space-based successor instrument. A number of active instruments, some employing new techniques, are being evaluated as candidate sources of stratospheric aerosol data. Herein, we examine suitability of the CALIPSO 532-nm aerosol backscatter coefficient measurements.

  1. Overview of ACE-Asia Spring 2001 Investigations on Aerosol Radiative Effects and Related Aerosol Properties

    NASA Technical Reports Server (NTRS)

    Russell, Philip B.; Valero, F. P. J.; Flatau, P. J.; Bergin, M.; Holben, B.; Nakajima, T.; Pilewskie, P.; Bergstrom, R.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    A primary, ACE-Asia objective was to quantify the interactions between aerosols and radiation in the Asia-Pacific region. Toward this end, radiometric and related aerosol measurements were made from ocean, land, air and space platforms. Models that predict aerosol fields guided the measurements and are helping integrate and interpret results. Companion overview's survey these measurement and modeling components. Here we illustrate how these components were combined to determine aerosol radiative. impacts and their relation to aerosol properties. Because clouds can obscure or change aerosol direct radiative effects, aircraft and ship sorties to measure these effects depended on predicting and finding cloud-free areas and times with interesting aerosols present. Pre-experiment satellite cloud climatologies, pre-flight aerosol and cloud forecasts, and in-flight guidance from satellite imagery all helped achieve this. Assessments of aerosol regional radiative impacts benefit from the spatiotemporal coverage of satellites, provided satellite-retrieved aerosol properties are accurate. Therefore, ACE-Asia included satellite retrieval tests, as part of many comparisons to judge the consistency (closure) among, diverse measurements. Early results include: (1) Solar spectrally resolved and broadband irradiances and optical depth measurements from the C-130 aircraft and at Kosan, Korea yielded aerosol radiative forcing efficiencies, permitting comparisons between efficiencies of ACE-Asia and INDOEX aerosols, and between dust and "pollution" aerosols. Detailed results will be presented in separate papers. (2) Based on measurements of wavelength dependent aerosol optical depth (AOD) and single scattering albedo the estimated 24-h a average aerosol radiative forcing efficiency at the surface for photosynthetically active radiation (400 - 700 nm) in Yulin, China is approx. 30 W sq m per AOD(500 nm). (3) The R/V Brown cruise from Honolulu to Sea of Japan sampled an aerosol optical

  2. WRF-Chem Simulations of Aerosols and Anthropogenic Aerosol Radiative Forcing in East Asia

    SciTech Connect

    Gao, Yi; Zhao, Chun; Liu, Xiaohong; Zhang, Meigen; Leung, Lai-Yung R.

    2014-08-01

    This study aims to provide a first comprehensive evaluation of WRF-Chem for modeling aerosols and anthropogenic aerosol radiative forcing (RF) over East Asia. Several numerical experiments were conducted from November 2007 to December 2008. Comparison between model results and observations shows that the model can generally reproduce the observed spatial distributions of aerosol concentration, aerosol optical depth (AOD) and single scattering albedo (SSA) from measurements at different sites, including the relatively higher aerosol concentration and AOD over East China and the relatively lower AOD over Southeast Asia, Korean, and Japan. The model also depicts the seasonal variation and transport of pollutions over East Asia. Particulate matter of 10 um or less in the aerodynamic diameter (PM10), black carbon (BC), sulfate (SO42-), nitrate (NO3-) and ammonium (NH4+) concentrations are higher in spring than other seasons in Japan due to the pollutant transport from polluted area of East Asia. AOD is high over Southwest and Central China in winter, spring and autumn and over North China in summer while is low over South China in summer due to monsoon precipitation. SSA is lowest in winter and highest in summer. The model also captures the dust events at the Zhangye site in the semi-arid region of China. Anthropogenic aerosol RF is estimated to range from -5 to -20 W m-2 over land and -20 to -40 W m-2 over ocean at the top of atmosphere (TOA), 5 to 30 W m-2 in the atmosphere (ATM) and -15 to -40 W m-2 at the bottom (BOT). The warming effect of anthropogenic aerosol in ATM results from BC aerosol while the negative aerosol RF at TOA is caused by scattering aerosols such as SO4 2-, NO3 - and NH4+. Positive BC RF at TOA compensates 40~50% of the TOA cooling associated with anthropogenic aerosol.

  3. Impact of aerosol size representation on modeling aerosol-cloud interactions

    DOE PAGES

    Zhang, Y.; Easter, R. C.; Ghan, S. J.; Abdul-Razzak, H.

    2002-11-07

    In this study, we use a 1-D version of a climate-aerosol-chemistry model with both modal and sectional aerosol size representations to evaluate the impact of aerosol size representation on modeling aerosol-cloud interactions in shallow stratiform clouds observed during the 2nd Aerosol Characterization Experiment. Both the modal (with prognostic aerosol number and mass or prognostic aerosol number, surface area and mass, referred to as the Modal-NM and Modal-NSM) and the sectional approaches (with 12 and 36 sections) predict total number and mass for interstitial and activated particles that are generally within several percent of references from a high resolution 108-section approach.more » The modal approach with prognostic aerosol mass but diagnostic number (referred to as the Modal-M) cannot accurately predict the total particle number and surface areas, with deviations from the references ranging from 7-161%. The particle size distributions are sensitive to size representations, with normalized absolute differences of up to 12% and 37% for the 36- and 12-section approaches, and 30%, 39%, and 179% for the Modal-NSM, Modal-NM, and Modal-M, respectively. For the Modal-NSM and Modal-NM, differences from the references are primarily due to the inherent assumptions and limitations of the modal approach. In particular, they cannot resolve the abrupt size transition between the interstitial and activated aerosol fractions. For the 12- and 36-section approaches, differences are largely due to limitations of the parameterized activation for non-log-normal size distributions, plus the coarse resolution for the 12-section case. Differences are larger both with higher aerosol (i.e., less complete activation) and higher SO2 concentrations (i.e., greater modification of the initial aerosol distribution).« less

  4. GCM Simulations of the Aerosol Indirect Effect: Sensitivity to Cloud Parameterization and Aerosol Burden

    NASA Technical Reports Server (NTRS)

    Menon, Surabi; DelGenio, Anthony D.; Koch, Dorothy; Tselioudis, George; Hansen, James E. (Technical Monitor)

    2001-01-01

    We describe the coupling of the Goddard Institute for Space Studies (GISS) general circulation model (GCM) to an online sulfur chemistry model and source models for organic matter and sea-salt that is used to estimate the aerosol indirect effect. The cloud droplet number concentration is diagnosed empirically from field experiment datasets over land and ocean that observe droplet number and all three aerosol types simultaneously; corrections are made for implied variations in cloud turbulence levels. The resulting cloud droplet number is used to calculate variations in droplet effective radius, which in turn allows us to predict aerosol effects on cloud optical thickness and microphysical process rates. We calculate the aerosol indirect effect by differencing the top-of-the-atmosphere net cloud radiative forcing for simulations with present-day vs. pre-industrial emissions. Both the first (radiative) and second (microphysical) indirect effects are explored. We test the sensitivity of our results to cloud parameterization assumptions that control the vertical distribution of cloud occurrence, the autoconversion rate, and the aerosol scavenging rate, each of which feeds back significantly on the model aerosol burden. The global mean aerosol indirect effect for all three aerosol types ranges from -1.55 to -4.36 W m(exp -2) in our simulations. The results are quite sensitive to the pre-industrial background aerosol burden, with low pre-industrial burdens giving strong indirect effects, and to a lesser extent to the anthropogenic aerosol burden, with large burdens giving somewhat larger indirect effects. Because of this dependence on the background aerosol, model diagnostics such as albedo-particle size correlations and column cloud susceptibility, for which satellite validation products are available, are not good predictors of the resulting indirect effect.

  5. GCM Simulations of the Aerosol Indirect Effect: Sensitivity to Cloud Parameterization and Aerosol Burden

    NASA Technical Reports Server (NTRS)

    Menon, Surabi; DelGenio, Anthony D.; Koch, Dorothy; Tselioudis, George; Hansen, James E. (Technical Monitor)

    2001-01-01

    We describe the coupling of the Goddard Institute for Space Studies (GISS) general circulation model (GCM) to an online sulfur chemistry model and source models for organic matter and sea-salt that is used to estimate the aerosol indirect effect. The cloud droplet number concentration is diagnosed empirically from field experiment datasets over land and ocean that observe droplet number and all three aerosol types simultaneously; corrections are made for implied variations in cloud turbulence levels. The resulting cloud droplet number is used to calculate variations in droplet effective radius, which in turn allows us to predict aerosol effects on cloud optical thickness and microphysical process rates. We calculate the aerosol indirect effect by differencing the top-of-the-atmosphere net cloud radiative forcing for simulations with present-day vs. pre-industrial emissions. Both the first (radiative) and second (microphysical) indirect effects are explored. We test the sensitivity of our results to cloud parameterization assumptions that control the vertical distribution of cloud occurrence, the autoconversion rate, and the aerosol scavenging rate, each of which feeds back significantly on the model aerosol burden. The global mean aerosol indirect effect for all three aerosol types ranges from -1.55 to -4.36 W/sq m in our simulations. The results are quite sensitive to the pre-industrial background aerosol burden, with low pre-industrial burdens giving strong indirect effects, and to a lesser extent to the anthropogenic aerosol burden, with large burdens giving somewhat larger indirect effects. Because of this dependence on the background aerosol, model diagnostics such as albedo-particle size correlations and column cloud susceptibility, for which satellite validation products are available, are not good predictors of the resulting indirect effect.

  6. Impact of aerosol size representation on modeling aerosol-cloud interactions

    SciTech Connect

    Zhang, Y.; Easter, R. C.; Ghan, S. J.; Abdul-Razzak, H.

    2002-11-07

    In this study, we use a 1-D version of a climate-aerosol-chemistry model with both modal and sectional aerosol size representations to evaluate the impact of aerosol size representation on modeling aerosol-cloud interactions in shallow stratiform clouds observed during the 2nd Aerosol Characterization Experiment. Both the modal (with prognostic aerosol number and mass or prognostic aerosol number, surface area and mass, referred to as the Modal-NM and Modal-NSM) and the sectional approaches (with 12 and 36 sections) predict total number and mass for interstitial and activated particles that are generally within several percent of references from a high resolution 108-section approach. The modal approach with prognostic aerosol mass but diagnostic number (referred to as the Modal-M) cannot accurately predict the total particle number and surface areas, with deviations from the references ranging from 7-161%. The particle size distributions are sensitive to size representations, with normalized absolute differences of up to 12% and 37% for the 36- and 12-section approaches, and 30%, 39%, and 179% for the Modal-NSM, Modal-NM, and Modal-M, respectively. For the Modal-NSM and Modal-NM, differences from the references are primarily due to the inherent assumptions and limitations of the modal approach. In particular, they cannot resolve the abrupt size transition between the interstitial and activated aerosol fractions. For the 12- and 36-section approaches, differences are largely due to limitations of the parameterized activation for non-log-normal size distributions, plus the coarse resolution for the 12-section case. Differences are larger both with higher aerosol (i.e., less complete activation) and higher SO2 concentrations (i.e., greater modification of the initial aerosol distribution).

  7. LASE measurements of aerosols and water vapor during TARFOX

    NASA Technical Reports Server (NTRS)

    Ferrare, Richard A.; Ismail, Syed; Browell, Edward V.; Brackett, Vincent G.; Kooi, Susan A.; Clayton, Marian B.; Melfi, Harvey; Whiteman, David N.; Schwenner, Geary; Evans, Keith D.; Hobbs, Peter V.; Veefkind, J. Pepijn; Russell, Philip B.; Livingston, John M.; Hignett, Philip; Holben, Brent N.; Remer, Lorraine A.

    1998-01-01

    The TARFOX (Tropospheric Aerosol Radiative Forcing Observational Experiment) intensive field campaign was designed to reduce uncertainties in estimates of the effects of anthropogenic aerosols on climate by measuring direct radiative effects and the optical, physical, and chemical properties of aerosols [1]. TARFOX was conducted off the East Coast of the United States between July 10-31, 1996. Ground, aircraft, and satellite-based sensors measured the sensitivity of radiative fields at various atmospheric levels to aerosol optical properties (i.e., optical thickness, phase function, single-scattering albedo) and to the vertical profile of aerosols. The LASE (Lidar Atmospheric Sensing Experiment) instrument, which was flown on the NASA ER-2 aircraft, measured vertical profiles of total scattering ratio and water vapor during a series of 9 flights. These profiles were used in real-time to help direct the other aircraft to the appropriate altitudes for intensive sampling of aerosol layers. We have subsequently used the LASE aerosol data to derive aerosol backscattering and extinction profiles. Using these aerosol extinction profiles, we derived estimates of aerosol optical thickness (AOT) and compared these with measurements of AOT from both ground and airborne sun photometers and derived from the ATSR-2 (Along Track and Scanning Radiometer 2) sensor on ERS-2 (European Remote Sensing Satellite-2). We also used the water vapor mixing ratio profiles measured simultaneously by LASE to derive precipitable water vapor and compare these to ground based measurements.

  8. Stratospheric aerosol geoengineering

    NASA Astrophysics Data System (ADS)

    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.

  9. Stratospheric aerosol geoengineering

    SciTech Connect

    Robock, Alan

    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.

  10. Aerosol lidar ``M4``

    SciTech Connect

    Shelevoy, C.D.; Andreev, Y.M. |

    1994-12-31

    Small carrying aerosol lidar in which is used small copper vapor laser ``Malachite`` as source of sounding optical pulses is described. The advantages of metal vapor laser and photon counting mode in acquisition system of lidar gave ability to get record results: when lidar has dimensions (1 x .6 x .3 m) and weight (65 kg), it provides the sounding of air industrial pollutions at up to 20 km range in scanning sector 90{degree}. Power feed is less than 800 Wt. Lidar can be disposed as stationary so on the car, helicopter, light plane. Results of location of smoke tails and city smog in situ experiments are cited. Showed advantages of work of acquisition system in photon counting mode when dynamic range of a signal is up to six orders.

  11. Polar organic marker compounds in atmospheric aerosols during the LBA-SMOCC 2002 biomass burning experiment in Rondônia, Brazil: sources and source processes, time series, diel variations and size distributions

    NASA Astrophysics Data System (ADS)

    Claeys, M.; Kourtchev, I.; Pashynska, V.; Vas, G.; Vermeylen, R.; Wang, W.; Cafmeyer, J.; Chi, X.; Artaxo, P.; Andreae, M. O.; Maenhaut, W.

    2010-04-01

    Measurements of polar organic marker compounds were performed on aerosols that were collected at a pasture site in the Amazon basin (Rondônia, Brazil) using a High-Volume dichotomous sampler (HVDS) and a Micro-Orifice Uniform Deposit Impactor (MOUDI). The samplings were conducted within the framework of the LBA-SMOCC (Large-Scale Biosphere Atmosphere Experiment in Amazônia - Smoke Aerosols, Clouds, Rainfall, and Climate: Aerosols From Biomass Burning Perturb Global and Regional Climate) campaign, which took place from 9 September till 14 November 2002, spanning the late dry season (biomass burning), the transition period, and the onset of the wet season (clean conditions). In the present study a more detailed discussion is presented compared to previous reports on the behavior of selected polar marker compounds, including: (a) levoglucosan, a tracer for biomass burning, (b) malic acid, a tracer for the oxidation of semivolatile carboxylic acids, (c) tracers for secondary organic aerosol (SOA) from isoprene, i.e., the 2-methyltetrols (2-methylthreitol and 2-methylerythritol) and the C5-alkene triols [2-methyl-1,3,4-trihydroxy-1-butene (cis and trans) and 3-methyl-2,3,4-trihydroxy-1-butene], and (d) sugar alcohols (arabitol, mannitol, and erythritol), tracers for fungal spores. The results obtained for levoglucosan are covered first with the aim to address its contrasting behavior with that of malic acid, the isoprene SOA tracers, and the fungal spore tracers. The tracer data are discussed taking into account new insights that recently became available into their stability and/or aerosol formation processes. During all three periods, levoglucosan was the most dominant identified organic species in the PM2.5 size fraction of the HVDS samples. In the dry period levoglucosan reached concentrations of up to 7.5 μg m-3 and exhibited diel variations with a nighttime prevalence. It was closely associated with the PM mass in the size-segregated samples and was mainly

  12. Aerosol Size Distribution in the marine regions

    NASA Astrophysics Data System (ADS)

    Markuszewski, Piotr; Petelski, Tomasz; Zielinski, Tymon; Pakszys, Paulina; Strzalkowska, Agata; Makuch, Przemyslaw; Kowalczyk, Jakub

    2014-05-01

    We would like to present the data obtained during the regular research cruises of the S/Y Oceania over a period of time between 2009 - 2012. The Baltic Sea is a very interesting polygon for aerosol measurements, however, also difficult due to the fact that mostly cases of a mixture of continental and marine aerosols are observed. It is possible to measure clear marine aerosol, but also advections of dust from southern Europe or even Africa. This variability of data allows to compare different conditions. The data is also compared with our measurements from the Arctic Seas, which have been made during the ARctic EXperiment (AREX). The Arctic Seas are very suitable for marine aerosol investigations since continental advections of aerosols are far less frequent than in other European sea regions. The aerosol size distribution was measured using the TSI Laser Aerosol Spectrometer model 3340 (99 channels, measurement range 0.09 μm to 7 μm), condensation particle counter (range 0.01 μm to 3 μm) and laser particle counter PMS CSASP-100-HV-SP (range 0.5 μm to 47 μm in 45 channels). 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. All equipment was placed on one of the masts of S/Y Oceania. Measurements using the laser aerosol spectrometer and condensation particle counter were made on one level (8 meters above sea level). Measurements with the laser particle counter were performed at five different levels above the sea level (8, 11, 14, 17 and 20 m). Based on aerosol size distribution the parameterizations with a Log-Normal and a Power-Law distributions were made. The aerosol source functions, characteristic for the region were also determined. Additionally, poor precision of the sea spray emission determination was confirmed while using only the aerosol concentration data. The emission of sea spray depends

  13. Scanning Mobile Lidar for Aerosol Tracking and Biological Aerosol Identification

    NASA Astrophysics Data System (ADS)

    He, Tingyao; Bergant, Klemen; Filipčič, Andrej; Forte, Biagio; Gao, Fei; Stanič, Samo; Veberič, Darko; Zavrtanik, Marko

    2010-05-01

    Optical properties of non-biological aerosols containing aromatic hydrocarbons, such as industrial chemicals and engine exhausts, have already been thoroughly studied using remote sensing techniques. However, because of their complex composition and characteristics, the identification of biological aerosols, such as fungi, pollen and bacteria that are present in the environment remains a rather difficult task. The collection of information on both non-biological and biological aerosols is of great importance for understanding their interrelation, physical and chemical properties and their influence on human health and the environment. Biological and non-biological aerosols can be simultaneously detected, tracked and identified by a scanning mobile Mie-fluorescence lidar. The device developed at the University of Nova Gorica can perform azimuth and zenith angle scans with an angular resolution of 0.1°, as well as operate in both day and night-time conditions. Aerosols of biological origin are identified through the detection of the fluorescence of the amino acid tryptophan which is present in almost all substances of biological origin. In our system, the transmitter is a solid state Nd:YAG laser which is capable of simultaneous emission of light at a base wavelength of 1064 nm (IR) and its quadrupled wavelength of 266 nm (UV) at a maximum repetition rate of 10 Hz. Tryptophan contained in biological aerosols is excited by the 266 nm laser pulses and the returning fluorescence signals are detected in the spectral band centered at 295 nm. The receiver is a Newtonian telescope which uses a 300 mm parabolic mirror to direct received light into three detection channels - two elastic backscatter channels (IR and UV) and a fluorescence channel. First experiments show that the detection range of the lidar reaches 10 km in the IR channel and 3 km in the UV channel. Based on the preliminary simulations of the signal-to-noise ratio, the detection range for biological

  14. Influence of semi-volatile aerosol on physical and optical properties of aerosol in Kathmandu valley

    NASA Astrophysics Data System (ADS)

    Shrestha, Sujan; Praveen, Ps; Adhikary, Bhupesh; Shrestha, Kundan; Panday, Arnico

    2016-04-01

    A field study was conducted in the urban atmosphere of Kathmandu valley to study the influence of the semi-volatile aerosol fraction on physical and optical properties of aerosols. The study was carried out during the 2015 pre-monsoon period. Experimental setup consisted of air from an ambient air inlet being split to two sets of identical sampling instruments. The first instrument received the ambient sample directly, while the second instrument received the air sample through a thermodenuder (TDD). Four sets of experiments were conducted to understand aerosol number, size distribution, scattering and absorption properties using Condensation Particle Counter (CPC), Scanning Mobility Particle Sizer (SMPS), Aethalometer (AE33) and Nephelometer. The influence of semi-volatile aerosols was calculated from the fraction of particles evaporated in the TDD at set temparetures: room temperature, 50°C, 100°C, 150°C, 200°C, 250°C and 300°C. Results show that, with increasing temperature, the evaporated fraction of semi-volatile aerosol also increased. At room temperature the fraction of semi-volatile aerosols was 12% while at 300°C it was as high as to 49%. Aerosol size distribution analysis shows that with an increase in TDD temperature from 50°C to 300°C, peak mobility diameter of particles shifted from around 60nm to 40nm. However we found little change in effective diameter of aerosol size distribution with increase in set TDD temperature. The change in size of aerosols due to loss of semi-volatile component has a stronger influence (~70%) in higher size bins when compared to at lower size bins (~20%). Studies using the AE33 showed that absorption by black carbon (BC) is amplified due to influence of semi-volatile aerosols by upto 37% at 880nm wavelength. Similarly nephelometer measurements showed that upto 71% of total scattering was found to be contributed by semi-volatile aerosol fraction. The scattering Angstrom Exponent (SAE) of semi-volatile aerosol

  15. Chemical characterization of secondary organic aerosol constituents from isoprene ozonolysis in the presence of acidic aerosol

    NASA Astrophysics Data System (ADS)

    Riva, Matthieu; Budisulistiorini, Sri Hapsari; Zhang, Zhenfa; Gold, Avram; Surratt, Jason D.

    2016-04-01

    Isoprene is the most abundant non-methane hydrocarbon emitted into Earth's atmosphere and is predominantly derived from terrestrial vegetation. Prior studies have focused largely on the hydroxyl (OH) radical-initiated oxidation of isoprene and have demonstrated that highly oxidized compounds, such as isoprene-derived epoxides, enhance the formation of secondary organic aerosol (SOA) through heterogeneous (multiphase) reactions on acidified sulfate aerosol. However, studies on the impact of acidified sulfate aerosol on SOA formation from isoprene ozonolysis are lacking and the current work systematically examines this reaction. SOA was generated in an indoor smog chamber from isoprene ozonolysis under dark conditions in the presence of non-acidified or acidified sulfate seed aerosol. The effect of OH radicals on SOA chemical composition was investigated using diethyl ether as an OH radical scavenger. Aerosols were collected and chemically characterized by ultra performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-QTOFMS) and gas chromatography/electron impact ionization-mass spectrometry (GC/EI-MS). Analysis revealed the formation of highly oxidized compounds, including organosulfates (OSs) and 2-methylterols, which were significantly enhanced in the presence of acidified sulfate seed aerosol. OSs identified in the chamber experiments were also observed and quantified in summertime fine aerosol collected from two rural locations in the southeastern United States during the 2013 Southern Oxidant and Aerosol Study (SOAS).

  16. Aerosol Absorption Measurements in MILAGRO.

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

    During the month of March 2006, a number of instruments were used to determine the absorption characteristics of aerosols found in the Mexico City Megacity and nearby Valley of Mexico. These measurements were taken as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX-Mex) that was carried out in collaboration with the Megacity Interactions: Local and Global Research Observations (MILAGRO) campaign. MILAGRO was a joint effort between the DOE, NSF, NASA, and Mexican agencies aimed at understanding the impacts of a megacity on the urban and regional scale. A super-site was operated at the Instituto Mexicano de Petroleo in Mexico City (designated T-0) and at the Universidad Technologica de Tecamac (designated T-1) that was located about 35 km to the north east of the T-0 site in the State of Mexico. A third site was located at a private rancho in the State of Hidalgo approximately another 35 km to the northeast (designated T-2). Aerosol absorption measurements were taken in real time using a number of instruments at the T-0 and T-1 sites. These included a seven wavelength aethalometer, a multi-angle absorption photometer (MAAP), and a photo-acoustic spectrometer. Aerosol absorption was also derived from spectral radiometers including a multi-filter rotating band spectral radiometer (MFRSR). The results clearly indicate that there is significant aerosol absorption by the aerosols in the Mexico City megacity region. The absorption can lead to single scattering albedo reduction leading to values below 0.5 under some circumstances. The absorption is also found to deviate from that expected for a "well-behaved" soot anticipated from diesel engine emissions, i.e. from a simple 1/lambda wavelength dependence for absorption. Indeed, enhanced absorption is seen in the region of 300-450 nm in many cases, particularly in the afternoon periods indicating that secondary organic aerosols are contributing to the aerosol absorption. This is likely due

  17. A brief overview of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) database and campaign operation centre (ChOC)

    NASA Astrophysics Data System (ADS)

    Ferré, Hélène; Dulac, François; Belmahfoud, Nizar; Brissebrat, Guillaume; Cloché, Sophie; Descloitres, Jacques; Fleury, Laurence; Focsa, Loredana; Henriot, Nicolas; Ramage, Karim; Vermeulen, Anne

    2016-04-01

    Initiated in 2010 in the framework of the multidisciplinary research programme MISTRALS (Mediterranean Integrated Studies at Regional and Local Scales; http:www.mistrals-home.org), the Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr/) aims at federating the scientific community for an updated assessment of the present and future state of the atmospheric environment in the Mediterranean Basin, and of its impacts on the regional climate, air quality, and marine biogeochemistry. The project combines mid- and long-term monitoring, intensive field campaigns, use of satellite data, and modelling studies. In this presentation we provide an overview of the campaign operation centre (http://choc.sedoo.fr/) and project database (http://mistrals.sedoo.fr/ChArMEx), at the end of the first experimental phase of the project that included a series of large campaigns based on airborne means (including balloons and various aircraft) and a network of surface stations. Those campaigns were performed mainly in the western Mediterranean basin in the summer of 2012, 2013 and 2014 with the help of the ChArMEx Operation Centre (ChOC), an open web site that has the objective to gather and display daily quick-looks from model forecasts and near-real time in situ and remote sensing observations of physical and chemical weather conditions relevant for the everyday campaign operation decisions. The ChOC is also useful for post campaign analyses and can be completed with a number of quick-looks of campaign results obtained later in order to offer an easy access to, and comprehensive view of all available data during the campaign period. The items included are selected according to the objectives and location of the given campaigns. The second experimental phase of ChArMEx from 2015 on is more focused on the eastern basin. In addition, the project operation centre is planned to be adapted for a joint MERMEX-ChArMEx oceanographic cruise (PEACETIME) for a study at

  18. A brief overview of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) database and campaign operation centre (ChOC)

    NASA Astrophysics Data System (ADS)

    Ferré, Hélène; Dulac, François; Belmahfoud, Nizar; Brissebrat, Guillaume; Cloché, Sophie; Descloitres, Jacques; Fleury, Laurence; Focsa, Loredana; Henriot, Nicolas; Ramage, Karim; Vermeulen, Anne

    2016-04-01

    Initiated in 2010 in the framework of the multidisciplinary research programme MISTRALS (Mediterranean Integrated Studies at Regional and Local Scales; http:www.mistrals-home.org), the Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr/) aims at federating the scientific community for an updated assessment of the present and future state of the atmospheric environment in the Mediterranean Basin, and of its impacts on the regional climate, air quality, and marine biogeochemistry. The project combines mid- and long-term monitoring, intensive field campaigns, use of satellite data, and modelling studies. In this presentation we provide an overview of the campaign operation centre (http://choc.sedoo.fr/) and project database (http://mistrals.sedoo.fr/ChArMEx), at the end of the first experimental phase of the project that included a series of large campaigns based on airborne means (including balloons and various aircraft) and a network of surface stations. Those campaigns were performed mainly in the western Mediterranean basin in the summer of 2012, 2013 and 2014 with the help of the ChArMEx Operation Centre (ChOC), an open web site that has the objective to gather and display daily quick-looks from model forecasts and near-real time in situ and remote sensing observations of physical and chemical weather conditions relevant for the everyday campaign operation decisions. The ChOC is also useful for post campaign analyses and can be completed with a number of quick-looks of campaign results obtained later in order to offer an easy access to, and comprehensive view of all available data during the campaign period. The items included are selected according to the objectives and location of the given campaigns. The second experimental phase of ChArMEx from 2015 on is more focused on the eastern basin. In addition, the project operation centre is planned to be adapted for a joint MERMEX-ChArMEx oceanographic cruise (PEACETIME) for a study at

  19. Effects of Aerosols over the Indian Ocean

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Aerosols that contain black carbon both absorb and reflect incoming sunlight. Even as these atmospheric particles reduce the amount of sunlight reaching the surface, they increase the amount of solar energy absorbed in the atmosphere, thus making it possible to both cool the surface and warm the atmosphere. The images above show satellite measurements of the region studied during the Indian Ocean Experiment (INDOEX)a vast region spanning the Arabian Sea and Bay of Bengal (west to east), and from the foot of the Himalayan Mountains, across the Indian subcontinent to the southern Indian Ocean (north to south). The Aerosol images show aerosol pollution (brownish pixels) in the lower atmosphere over the INDOEX study area, as measured by the Moderate-resolution Imaging Spectroradiometer (MODIS) aboard Terra. These were composited from March 14-21, 2001. The Albedo images show the total solar energy reflected back to space, as measured by Clouds and Earth's Radiant Energy System (CERES) aboard Terra. White pixels show high values, greens are intermediate values, and blues are low. Note how the aerosols, particularly over the ocean, increase the amount of energy reflected back to space. The Atmospheric Warming images show the absorption of the black carbon aerosols in the atmosphere. Where the aerosols are most dense, the absorption is highest. Red pixels indicate the highest levels of absorption, blues are low. The Surface Cooling images show that the aerosol particles reduce the amount of sunlight reaching the surface. Dark pixels show where the aerosols exert their cooling influence on the surface (or a high magnitude of negative radiative forcing). The bright pixels show where there is much less aerosol pollution and the incoming sunlight is relatively unaffected.

  20. Light Absorbing Aerosols in Mexico City

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    The direct effects of aerosol radiative forcing has been identified by the IPCC as a major uncertainty in climate modeling. The DOE Megacity Aerosol Experiment-Mexico City (MAX-Mex), as part of the MILAGRO study in March of 2006, was undertaken to reduce these uncertainties by characterization of the optical, chemical, and physical properties of atmospheric aerosols emitted from this megacity environment. Aerosol samples collected during this study using quartz filters were characterized in the uv-visible-infrared by using surface spectroscopic techniques. These included the use of an integrating sphere approach combined with the use of Kubelka-Munk theory to obtain aerosol absorption spectra. In past work black carbon has been assumed to be the only major absorbing species in atmospheric aerosols with an broad band spectral profile that follows a simple inverse wavelength dependence. Recent work has also identified a number of other absorbing species that can also add to the overall aerosol absorption. These include primary organics from biomass and trash burning and secondary organic aerosols including nitrated PAHs and humic-like substances, or HULIS. By using surface diffuse reflection spectroscopy we have also obtained spectra in the infrared that indicate significant IR absorption in the atmospheric window-region. These data will be presented and compared to spectra of model compounds that allow for evaluation of the potential importance of these species in adding strength to the direct radiative forcing of atmospheric aerosols. This work was supported by the Office of Science (BER), U.S. Department of Energy, Grant No. DE-FG02-07ER64327 as part of the Atmospheric Science Program.

  1. Attachment of radon progeny to cigarette-smoke aerosols

    SciTech Connect

    Biermann, A.H.; Sawyer, S.R.

    1995-05-01

    The daughter products of radon gas are now recognized as a significant contributor to radiation exposure to the general public. It is also suspected that a synergistic effect exists with the combination cigarette smoking and radon exposure. We have conducted an experimental investigation to determine the physical nature of radon progeny interactions with cigarette smoke aerosols. The size distributions of the aerosols are characterized and attachment rates of radon progeny to cigarette-smoke aerosols are determined. Both the mainstream and sidestream portions of the smoke aerosol are investigated. Unattached radon progeny are very mobile and, in the presence of aerosols, readily attach to the particle surfaces. In this study, an aerosol chamber is used to contain the radon gas, progeny and aerosol mixture while allowing the attachment process to occur. The rate of attachment is dependent on the size distribution, or diffusion coefficient, of the radon progeny as well as the aerosol size distribution. The size distribution of the radon daughter products is monitored using a graded-screen diffusion battery. The diffusion battery also enables separation of the unattached radon progeny from those attached to the aerosol particles. Analysis of the radon decay products is accomplished using alpha spectrometry. The aerosols of interest are size fractionated with the aid of a differential mobility analyzer and cascade impactor. The measured attachment rates of progeny to the cigarette smoke are compared to those found in similar experiments using an ambient aerosol. The lowest attachment coefficients observed, {approximately}10{sup {minus}6} cm{sup 3}/s, occurred for the ambient aerosol. The sidestream and mainstream smoke aerosols exhibited higher attachment rates in that order. The results compared favorably with theories describing the coagulation process of aerosols.

  2. Climatology of Aerosol Optical Properties in Southern Africa

    NASA Technical Reports Server (NTRS)

    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

  3. Aerosol sampling and Transport Efficiency Calculation (ASTEC) and application to surtsey/DCH aerosol sampling system: Code version 1. 0: Code description and user's manual

    SciTech Connect

    Yamano, N.; Brockmann, J.E.

    1989-05-01

    This report describes the features and use of the Aerosol Sampling and Transport Efficiency Calculation (ASTEC) Code. The ASTEC code has been developed to assess aerosol transport efficiency source term experiments at Sandia National Laboratories. This code also has broad application for aerosol sampling and transport efficiency calculations in general as well as for aerosol transport considerations in nuclear reactor safety issues. 32 refs., 31 figs., 7 tabs.

  4. Humidity Dependent Extinction of Clay Aerosols

    NASA Astrophysics Data System (ADS)

    Greenslade, M. E.; Attwood, A. R.

    2010-12-01

    Aerosols play an important role in the Earth’s radiative balance by directly scattering and absorbing radiation. The magnitude of aerosol forcing can be altered by changes in relative humidity which cause aerosol size, shape and refractive index to vary. To quantify these effects, a custom cavity ring down instrument operated at 532 nm with two sample channels measures aerosols extinction under dry conditions and at elevated humidity. The optical growth, fRH(ext), is determined as a ratio of the extinction cross section at high relative humidity to that under dry conditions. Three key clay components of mineral dust and mixtures of clay components with ammonium sulfate are investigated using this method. Experimentally obtained optical growth is compared with physical growth factors from the literature and our work determined using several different techniques. Further, Mie theory calculations based on published optical constants are compared with experimental results. Differences between theory and experiment will be discussed.

  5. Remote sensing of aerosol properties during CARES

    NASA Astrophysics Data System (ADS)

    Kassianov, Evgueni; Barnard, James; Pekour, Mikhail; Flynn, Connor; Ferrare, Richard; Hostetler, Chris; Hair, John; Jobson, Bertram T.

    2011-11-01

    One month of MFRSR data collected at two sites in the central California (USA) region during the CARES campaign are processed and the MFRSR-derived AODs at 500 nm wavelength are compared with available AODs provided by AERONET measurements. We find that the MFRSR and AERONET AODs are small (~0.05) and comparable. A reasonable quantitative agreement between column aerosol size distributions (up to 2 μm) from the MFRSR and AERONET retrievals is illustrated as well. Analysis of the retrieved (MFRSR and AERONET) and in situ measured aerosol size distributions suggests that the contribution of the coarse mode to aerosol optical properties is substantial for several days. The results of a radiative closure experiment performed for the two sites and one-month period show a favorable agreement between the calculated and measured broadband downwelling irradiances (bias does not exceed about 3 Wm-2), and thus imply that the MFRSR-derived aerosol optical properties are reasonable.

  6. Remote Sensing of Aerosol Properties during CARES

    SciTech Connect

    Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Flynn, Connor J.; Ferrare, R.; Hostetler, Chris A.; Hair, John; Jobson, Bertram Thomas

    2011-10-01

    One month of MFRSR data collected at two sites in the central California (USA) region during the CARES campaign are processed and the MFRSR-derived AODs at 500 nm wavelength are compared with available AODs provided by AERONET measurements. We find that the MFRSR and AERONET AODs are small ({approx}0.05) and comparable. A reasonable quantitative agreement between column aerosol size distributions (up to 2 um) from the MFRSR and AERONET retrievals is illustrated as well. Analysis of the retrieved (MFRSR and AERONET) and in situ measured aerosol size distributions suggests that the contribution of the coarse mode to aerosol optical properties is substantial for several days. The results of a radiative closure experiment performed for the two sites and one-month period show a favorable agreement between the calculated and measured broadband downwelling irradiances (bias does not exceed about 3 Wm-2), and thus imply that the MFRSR-derived aerosol optical properties are reasonable.

  7. Interpretation of FRESCO cloud retrievals in case of absorbing aerosol events

    NASA Astrophysics Data System (ADS)

    Wang, P.; Tuinder, O. N. E.; Tilstra, L. G.; de Graaf, M.; Stammes, P.

    2012-10-01

    Cloud and aerosol information is needed in trace gas retrievals from satellite measurements. The Fast REtrieval Scheme for Clouds from the Oxygen A band (FRESCO) cloud algorithm employs reflectance spectra of the O2 A band around 760 nm to derive cloud pressure and effective cloud fraction. In general, clouds contribute more to the O2 A band reflectance than aerosols. Therefore, the FRESCO algorithm does not correct for aerosol effects in the retrievals and attributes the retrieved cloud information entirely to the presence of clouds, and not to aerosols. For events with high aerosol loading, aerosols may have a dominant effect, especially for almost cloud free scenes. We have analysed FRESCO cloud data and Absorbing Aerosol Index (AAI) data from the Global Ozone Monitoring Experiment (GOME-2) instrument on the Metop-A satellite for events with typical absorbing aerosol types, such as volcanic ash, desert dust and smoke. We find that the FRESCO effective cloud fractions are correlated with the AAI data for these absorbing aerosol events and that the FRESCO cloud pressure contains information on aerosol layer pressure. For cloud free scenes, the derived FRESCO cloud pressure is close to the aerosol layer pressure, especially for optically thick aerosol layers. For cloudy scenes, if the strongly absorbing aerosols are located above the clouds, then the retrieved FRESCO cloud pressure may represent the height of the aerosol layer rather than the height of the clouds. Combining FRESCO and AAI data, an estimate for the aerosol layer pressure can be given.

  8. Concentration and composition of atmospheric aerosols from the 1995 SEAVS experiment and a review of the closure between chemical and gravimetric measurements.

    PubMed

    Andrews, E; Saxena, P; Musarra, S; Hildemann, L M; Koutrakis, P; McMurry, P H; Olmez, I; White, W H

    2000-05-01

    We summarize the results from the various measurements and the inter-sampler comparisons from Southeastern Aerosol and Visibility Study (SEAVS), a study with one of its objectives to test for closure among chemical, gravimetric and optical measurements of atmospheric aerosol particles. Sulfate and organics are the dominant components of the SEAVS fine particles (nominally, particles with aerodynamic diameter < or = 2.5 microns) but between 28 and 42% (range over various samplers) of the gravimetrically measured total fine particle concentration is unidentified by the chemical measurements. Estimates of water associated with inorganic components and measurement imprecision do not totally explain the observed difference between gravimetric and chemical measurements. We examine the theoretical and empirical basis for assumptions commonly made in the published literature to extrapolate total fine particle concentration on the basis of chemical measurements of ions, carbon and elements. We then explore the more general question of closure using the SEAVS data as well as data from other, similar studies reported in the literature. In so combining the SEAVS measurements with other similar studies, we find a strong association between organic carbon and the unidentified component, that is, the fraction of the total fine particle concentration not identified by chemical measurements. We offer several tenable hypotheses for the relationship between the organic and unidentified components that deserve to be tested in future work. Specifically, we hypothesize that (1) errors in the sampling and analysis of organic carbon; (2) estimates of organic mass from measurements of organic carbon; and/or (3) water absorption by organics may all contribute to the observed relationship.

  9. Evaluation of vegetation fire smoke plume dynamics and aerosol load using UV scanning lidar and fire-atmosphere modelling during the Mediterranean Letia 2010 experiment

    NASA Astrophysics Data System (ADS)

    Leroy-Cancellieri, V.; Augustin, P.; Filippi, J. B.; Mari, C.; Fourmentin, M.; Bosseur, F.; Morandini, F.; Delbarre, H.

    2013-08-01

    Vegetation fires emit large amount of gases and aerosols which are detrimental to human health. Smoke exposure near and downwind of fires depends on the fire propagation, the atmospheric circulations and the burnt vegetation. A better knowledge of the interaction between wildfire and atmosphere is a primary requirement to investigate fire smoke and particle transport. The purpose of this paper is to highlight the usefulness of an UV scanning lidar to characterize the fire smoke plume and consequently validate fire-atmosphere model simulations. An instrumented burn was conducted in a Mediterranean area typical of ones frequently concern by wildfire with low dense shrubs. Using Lidar measurements positioned near the experimental site, fire smoke plume was thoroughly characterized by its optical properties, edge and dynamics. These parameters were obtained by combining methods based on lidar inversion technique, wavelet edge detection and a backscatter barycenter technique. The smoke plume displacement was determined using a digital video camera coupled with the Lidar. The simulation was performed using a meso-scale atmospheric model in a large eddy simulation configuration (Meso-NH) coupled to a fire propagation physical model (ForeFire) taking into account the effect of wind, slope and fuel properties. A passive numerical scalar tracer was injected in the model at fire location to mimic the smoke plume. The simulated fire smoke plume width remained within the edge smoke plume obtained from lidar measurements. The maximum smoke injection derived from lidar backscatter coefficients and the simulated passive tracer was around 200 m. The vertical position of the simulated plume barycenter was systematically below the barycenter derived from the lidar backscatter coefficients due to the oversimplified properties of the passive tracer compared to real aerosols particles. Simulated speed and horizontal location of the plume compared well with the observations derived from

  10. Evaluation of wildland fire smoke plume dynamics and aerosol load using UV scanning lidar and fire-atmosphere modelling during the Mediterranean Letia 2010 experiment

    NASA Astrophysics Data System (ADS)

    Leroy-Cancellieri, V.; Augustin, P.; Filippi, J. B.; Mari, C.; Fourmentin, M.; Bosseur, F.; Morandini, F.; Delbarre, H.

    2014-03-01

    Vegetation fires emit large amount of gases and aerosols which are detrimental to human health. Smoke exposure near and downwind of fires depends on the fire propagation, the atmospheric circulations and the burnt vegetation. A better knowledge of the interaction between wildfire and atmosphere is a primary requirement to investigate fire smoke and particle transport. The purpose of this paper is to highlight the usefulness of an UV scanning lidar to characterise the fire smoke plume and consequently validate fire-atmosphere model simulations. An instrumented burn was conducted in a Mediterranean area typical of ones frequently subject to wildfire with low dense shrubs. Using lidar measurements positioned near the experimental site, fire smoke plume was thoroughly characterised by its optical properties, edge and dynamics. These parameters were obtained by combining methods based on lidar inversion technique, wavelet edge detection and a backscatter barycentre technique. The smoke plume displacement was determined using a digital video camera coupled with the lidar. The simulation was performed using a mesoscale atmospheric model in a large eddy simulation configuration (Meso-NH) coupled to a fire propagation physical model (ForeFire), taking into account the effect of wind, slope and fuel properties. A passive numerical scalar tracer was injected in the model at fire location to mimic the smoke plume. The simulated fire smoke plume width remained within the edge smoke plume obtained from lidar measurements. The maximum smoke injection derived from lidar backscatter coefficients and the simulated passive tracer was around 200 m. The vertical position of the simulated plume barycentre was systematically below the barycentre derived from the lidar backscatter coefficients due to the oversimplified properties of the passive tracer compared to real aerosol particles. Simulated speed and horizontal location of the plume compared well with the observations derived from

  11. Aerosol MTF revisited

    NASA Astrophysics Data System (ADS)

    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.

  12. Characterization of gas-aerosol interaction kinetics using morphology dependent stimulated Raman scattering. Final technical report

    SciTech Connect

    Aker, P.M.

    1992-12-31

    A research program on the influence of aerosol surface structure on the kinetics of gas-aerosol interactions is proposed. The experiments involve measuring changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol. Aerosols with differing surface properties will be generated by changing the composition and/or temperature of the material making up the aerosol. Kinetic data generated can be used directly in atmospheric modelling calculations. The surface structure of the aerosol will be measured, both before and after reaction, using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Information about the detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during the course of the reaction. Studies will focus on the condensation and oxidation of sulfur species (sulfur dioxide and dimethyl sulfide) on water aerosols.

  13. Characterization of gas-aerosol interaction kinetics using morphology dependent stimulated Raman scattering

    SciTech Connect

    Aker, P.M.

    1992-01-01

    A research program on the influence of aerosol surface structure on the kinetics of gas-aerosol interactions is proposed. The experiments involve measuring changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol. Aerosols with differing surface properties will be generated by changing the composition and/or temperature of the material making up the aerosol. Kinetic data generated can be used directly in atmospheric modelling calculations. The surface structure of the aerosol will be measured, both before and after reaction, using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Information about the detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during the course of the reaction. Studies will focus on the condensation and oxidation of sulfur species (sulfur dioxide and dimethyl sulfide) on water aerosols.

  14. Thermoluminescent aerosol analysis

    NASA Technical Reports Server (NTRS)

    Rogowski, R. S.; Long, E. R., Jr. (Inventor)

    1977-01-01

    A method for detecting and measuring trace amounts of aerosols when reacted with ozone in a gaseous environment was examined. A sample aerosol was exposed to a fixed ozone concentration for a fixed period of time, and a fluorescer was added to the exposed sample. The sample was heated in a 30 C/minute linear temperature profile to 200 C. The trace peak was measured and recorded as a function of the test aerosol and the recorded thermoluminescence trace peak of the fluorescer is specific to the aerosol being tested.

  15. MELCOR aerosol transport module modification for NSSR-1

    SciTech Connect

    Merrill, B.J.; Hagrman, D.L.

    1996-03-01

    This report describes modifications of the MELCOR computer code aerosol transport module that will increase the accuracy of calculations for safety analysis of the International Thermonuclear Experimental Reactor (ITER). The modifications generalize aerosol deposition models to consider gases other than air, add specialized models for aerosol deposition during high speed gas flows in ducts, and add models for resuspension of aerosols that are entrained in coolants when these coolants flash. Particular attention has been paid to the adhesion of aerosol particles once they are transported to duct walls. The results of calculations with the modified models have been successfully compared to data from Light Water Reactor Aerosol Containment Experiments (LACE) conducted by an international consortium at Hanford, Washington.

  16. SAGE Aerosol Measurements. Volume 2: 1 January - 31 December 1980

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.

    1986-01-01

    The stratospheric Aerosol and Gas Experiment (SAGE) satellite system, launched on February 18, 1979, provides profiles of aerosol extinction at wavelengths of 1.00 and 0.45 micron, ozone concentration, and nitrogen dioxide concentration. Data taken during sunset events in the form of zonal averages and seasonal averages of the aerosol extinction at 1.00 and 0.45 micron, ratios of the aerosol extinction to the molecular extinction at 1.00 micron, and ratios of the aerosol extinction at 0.45 micron to the aerosol extinction at 1.00 micron are presented. The averages for l980 are shown in tables and in profile and contour plots (as a function of altitude and latitude). In addition, temperature data provided by the National Oceanic and Atmospheric Administration (NOAA) for the time and location of each SAGE measurement are averaged and shown in a similar format.

  17. The Role of Anthropogenic Aerosol in Atmospheric Circulation Changes

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  18. A general circulation model (GCM) parameterization of Pinatubo aerosols

    SciTech Connect

    Lacis, A.A.; Carlson, B.E.; Mishchenko, M.I.

    1996-04-01

    The June 1991 volcanic eruption of Mt. Pinatubo is the largest and best documented global climate forcing experiment in recorded history. The time development and geographical dispersion of the aerosol has been closely monitored and sampled. Based on preliminary estimates of the Pinatubo aerosol loading, general circulation model predictions of the impact on global climate have been made.

  19. Aerosols in clean and smoky air at Bozeman, Montana

    NASA Astrophysics Data System (ADS)

    Shaw, J. A.; Thomas, M.; Lathem, T. L.; Shaw, G. E.; Nenes, A.; Pust, N.; Repasky, K. S.

    2010-12-01

    The northern Rocky Mountain region of the United States is a natural laboratory for studying aerosols in a relatively uncontaminated environment punctuated by episodes of wildfire smoke. In autumn 2009, we conducted a field experiment at Montana State University in Bozeman, Montana to characterize the boundary layer aerosols as they transition from smoky periods to relatively clean background air. Physical and chemical properties of the aerosols were conducted, including high time resolution of Cloud Condensation Nuclei and inter comparison with AERONET data during times of deep atmospheric mixing. The key results of this experiment are: 1) the air in this northern Rocky Mountain location is surprisingly pristine with frequent aerosol size distributions devoid of a an accumulation mode; 2) periods of night-time growth of Aitken-mode aerosols were observed; 3) a persistent diurnal variation occurred, with upslope daytime winds bringing aerosols exhibiting moderate anthropogenic influence , and down slope nighttime winds bringing aerosols with weak accumulation mode; 4) the smoke aerosol was weakly soluble; and 5) satisfactory agreement was found between the inverted estimate of the fine mode aerosol from AERONET solar radiometry with that measured in situ.

  20. Regional and monthly and clear-sky aerosol direct radiative effect (and forcing) derived from the GlobAEROSOL-AATSR satellite aerosol product

    NASA Astrophysics Data System (ADS)

    Thomas, G. E.; Chalmers, N.; Harris, B.; Grainger, R. G.; Highwood, E. J.

    2013-01-01

    Using the GlobAEROSOL-AATSR dataset, estimates of the instantaneous, clear-sky, direct aerosol radiative effect and radiative forcing have been produced for the year 2006. Aerosol Robotic Network sun-photometer measurements have been used to characterise the random and systematic error in the GlobAEROSOL product for 22 regions covering the globe. Representative aerosol properties for each region were derived from the results of a wide range of literature sources and, along with the de-biased GlobAEROSOL AODs, were used to drive an offline version of the Met Office unified model radiation scheme. In addition to the mean AOD, best-estimate run of the radiation scheme, a range of additional calculations were done to propagate uncertainty estimates in the AOD, optical properties, surface albedo and errors due to the temporal and spatial averaging of the AOD fields. This analysis produced monthly, regional estimates of the clear-sky aerosol radiative effect and its uncertainty, which were combined to produce annual, global mean values of (-6.7 ± 3.9) W m-2 at the top of atmosphere (TOA) and (-12 ± 6) W m-2 at the surface. These results were then used to give estimates of regional, clear-sky aerosol direct radiative forcing, using modelled pre-industrial AOD fields for the year 1750 calculated for the AEROCOM PRE experiment. However, as it was not possible to quantify the uncertainty in the pre-industrial aerosol loading, these figures can only be taken as indicative and their uncertainties as lower bounds on the likely errors. Although the uncertainty on aerosol radiative effect presented here is considerably larger than most previous estimates, the explicit inclusion of the major sources of error in the calculations suggest that they are closer to the true constraint on this figure from similar methodologies, and point to the need for more, improved estimates of both global aerosol loading and aerosol optical properties.

  1. Regional and monthly and clear-sky aerosol direct radiative effect (and forcing) derived from the GlobAEROSOL-AATSR satellite aerosol product

    NASA Astrophysics Data System (ADS)

    Thomas, G. E.; Chalmers, N.; Harris, B.; Grainger, R. G.; Highwood, E. J.

    2012-07-01

    Using the GlobAEROSOL-AATSR dataset, estimates of the instantaneous, clear-sky, direct aerosol radiative effect and radiative forcing have been produced for the year 2006. Aerosol Robotic Network sun-photometer measurements have been used to characterise the random and systematic error in the GlobAEROSOL product for 22 regions covering the globe. Representative aerosol properties for each region have been derived from the results of a wide range of literature sources and, along with the de-biased GlobAEROSOL AODs, were used to drive an offline version of the Met Office unified model radiation scheme. In addition to the mean AOD, best-estimate run of the radiation scheme, a range of additional calculations were done to propagate uncertainty estimates in the AOD, optical properties, surface albedo and errors due to the temporal and spatial averaging of the AOD fields. This analysis produced monthly, regional estimates of the clear-sky aerosol radiative effect and its uncertainty, which produce annual, global mean values of (-6.7 ± 3.9) W m-2 at the top of atmosphere (TOA) and (-12 ± 6) W m-2 at the surface. These results were then used to produce estimates of regional, clear-sky aerosol direct radiative forcing, using modelled pre-industrial AOD fields for 1750 calculated for the AEROCOM PRE experiment. However, as it was not possible to quantify the uncertainty in the pre-industrial aerosol loading, these figures can only be taken as indicative and their uncertainties as lower bounds on the likely errors. Although the uncertainty on aerosol radiative effect presented here is considerably larger than most previous estimates, the explicit inclusion of the major sources of error in the calculations suggest that they are closer to the true constraint on this figure from similar methodologies, and point to the need for more, improved estimates of both global aerosol loading and aerosol optical properties.

  2. Anthropogenic Aerosol Dimming Over Oceans: A Regional Analysis

    NASA Astrophysics Data System (ADS)

    Dallafior, T. N.; Folini, D.; Knutti, R.; Wild, M.

    2015-12-01

    The role of anthropogenic aerosols in shaping 20th century SSTs through alteration of surface solar radiation (SSR) is still subject to debate. Identifying and quantifying the relationship between aerosol-induced changes in SSR and the corresponding SST response is difficult due to the masking effect of numerous feedback mechanisms and general variability of the atmosphere-ocean system. We therefore analysed potential anthropogenic aerosol effects on SST with a cascade of experiments of increasing complexity: From atmosphere-only over mixed-layer ocean (MLO) experiments, to fully coupled transient ocean-atmosphere simulations, with and without greenhouse gases and / or aerosols, using the general circulation model ECHAM with explicit aerosol representation. We find anthropogenic aerosols to be crucial to obtain realistic SSR and SST patterns, although co-location of changes in individual variables (aerosol optical depth, SSR, SST) is weak. The effect of greenhouse gases and aerosols in the MLO simulations is essentially additive on global and regional scales, an assumption frequently made in the literature. With atmosphere-only simulations we identified regions most prone to anthropogenic aerosol dimming throughout the 20th century using a strict criterion. From MLO equilibria representative of different decades throughout the 20th century, we identified ocean regions, whose SSTs are most sensitive to changing anthropogenic aerosol emissions. The surface temperature response patterns in our MLO simulations are more sensitive towards the choice of prescribed deep-ocean heat flux if anthropogenic aerosols were included as compared to greenhouse gas only simulations. This implies that ocean dynamics might mask some of the response and cautions against the use of just one set of deep-ocean heat fluxes in MLO studies. Our results corroborate not only the relevance of anthropogenic aerosols for SST responses, but also highlight the complexity and non-locality of the

  3. Sun photometer aerosol retrievals during SALTRACE

    NASA Astrophysics Data System (ADS)

    Toledano, Carlos; Torres, Benjamin; Althausen, Dietrich; Groß, Silke; Freudenthaler, Volker; Weinzierl, Bernadett; Gasteiger, Josef; Ansmann, Albert; Wiegner, Matthias; González, Ramiro; Cachorro, Victoria

    2015-04-01

    The Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE), aims at investigating the long-range transport of Saharan dust across the Atlantic Ocean. A large set of ground-based and airborne aerosol and meteorological instrumentation was used for this purpose during a 5-week campaign that took place during June-July 2013. Several Sun photometers were deployed at Barbados Island during this campaign. Two Cimels included in AERONET and the Sun and Sky Automatic Radiometer (SSARA) were co-located with the ground-based lidars BERTHA and POLIS. A set of optical and microphysical aerosol properties derived from Sun and Sky spectral observations (principal plane and almucantar configurations) in the range 340-1640nm are analyzed, including aerosol optical depth (AOD), volume size distribution, complex refractive index, sphericity and single scattering albedo. The Sun photometers include polarization capabilities, therefore apart from the inversion of sky radiances as it is routinely done in AERONET, polarized radiances are also inverted. Several dust events are clearly identified in the measurement period, with moderated AOD (500nm) in the range 0.3 to 0.6. The clean marine background was also observed during short periods. The retrieved aerosol properties are compared with the lidar and in-situ observations carried out within SALTRACE, as well as with data collected during the SAMUM campaigns in Morocco and Cape Verde, in order to investigate possible changes in the dust plume during the transport.

  4. Errors incurred in a plane-wave-type expansion of a Gaussian beam. [in laser force calculations on light scattering aerosol experiments

    NASA Technical Reports Server (NTRS)

    Kattawar, G. W.

    1980-01-01

    The multipole expansion obtained by Morita et al. (1968) of the Gaussian laser beam used to levitate an aerosol particle in order that its complete phase matrix may be measured is compared with that of Tsai and Pogorzelski (1975) in order to demonstrate the effect of the incorrect expansion used by Morita. Errors incurred by the use of an equation in which one side satisfies the scalar wave equation while the other side does not and can be reduced to a plane wave amplitude are calculated as functions of the inverse of the wave number times the beam waist, the wave number times the radial spherical coordinate and the angular spherical coordinate. Errors on the order of a few percent, considered undetectable are obtained in the squared-field amplitudes due to the expansion, however, they are found to become significant (several tens of percent) when the angle is zero. It is concluded that the expansion of Morita should only be used in the regions where the spherical angle is less than 0.01 and its product with the wave number and the radial spherical coordinate is less than unity.

  5. Portable Aerosol Contaminant Extractor

    DOEpatents

    Carlson, Duane C.; DeGange, John J.; Cable-Dunlap, Paula

    2005-11-15

    A compact, portable, aerosol contaminant extractor having ionization and collection sections through which ambient air may be drawn at a nominal rate so that aerosol particles ionized in the ionization section may be collected on charged plate in the collection section, the charged plate being readily removed for analyses of the particles collected thereon.

  6. Global Aerosol Observations

    Atmospheric Science Data Center

    2013-04-19

    ... atmosphere, directly influencing global climate and human health. Ground-based networks that accurately measure column aerosol amount and ... being used to improve Air Quality Models and for regional health studies. To assess the human-health impact of chronic aerosol exposure, ...

  7. Direct Aerosol Forcing Uncertainty

    DOE Data Explorer

    Mccomiskey, Allison

    2008-01-15

    Understanding sources of uncertainty in aerosol direct radiative forcing (DRF), the difference in a given radiative flux component with and without aerosol, is essential to quantifying changes in Earth's radiation budget. We examine the uncertainty in DRF due to measurement uncertainty in the quantities on which it depends: aerosol optical depth, single scattering albedo, asymmetry parameter, solar geometry, and surface albedo. Direct radiative forcing at the top of the atmosphere and at the surface as well as sensitivities, the changes in DRF in response to unit changes in individual aerosol or surface properties, are calculated at three locations representing distinct aerosol types and radiative environments. The uncertainty in DRF associated with a given property is computed as the product of the sensitivity and typical measurement uncertainty in the respective aerosol or surface property. Sensitivity and uncertainty values permit estimation of total uncertainty in calculated DRF and identification of properties that most limit accuracy in estimating forcing. Total uncertainties in modeled local diurnally averaged forcing range from 0.2 to 1.3 W m-2 (42 to 20%) depending on location (from tropical to polar sites), solar zenith angle, surface reflectance, aerosol type, and aerosol optical depth. The largest contributor to total uncertainty in DRF is usually single scattering albedo; however decreasing measurement uncertainties for any property would increase accuracy in DRF. Comparison of two radiative transfer models suggests the contribution of modeling error is small compared to the total uncertainty although comparable to uncertainty arising from some individual properties.

  8. Analysis of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Prather, Kimberly A.; Hatch, Courtney D.; Grassian, Vicki H.

    2008-07-01

    Aerosols represent an important component of the Earth's atmosphere. Because aerosols are composed of solid and liquid particles of varying chemical complexity, size, and phase, large challenges exist in understanding how they impact climate, health, and the chemistry of the atmosphere. Only through the integration of field, laboratory, and modeling analysis can we begin to unravel the roles atmospheric aerosols play in these global processes. In this article, we provide a brief review of the current state of the science in the analysis of atmospheric aerosols and some important challenges that need to be overcome before they can become fully integrated. It is clear that only when these areas are effectively bridged can we fully understand the impact that atmospheric aerosols have on our environment and the Earth's system at the level of scientific certainty necessary to design and implement sound environmental policies.

  9. Is benzene a precursor for secondary organic aerosol?

    PubMed

    Martín-Reviejo, Montserrat; Wirtz, Klaus

    2005-02-15

    It is currently assumed that benzene contributes only negligibly to secondary organic aerosol formation in the atmosphere. Our understanding of the capacity of benzene to generate secondary aerosols is based on the work of Izumi and Fukuyama (Atmos. Environ. 1990, 24A, 1433) in which two photosmog experiments with benzene in the presence of NOx were performed and no particle formation was observed. In contrast to the observations of Izumi and Fukuyama, experiments performed in the EUPHORE large outdoor simulation chamber have clearly shown aerosol formation during the photochemical oxidation of benzene in various NOx regimes. The maximum aerosol yields of 8-25% on a mass basis are comparable to yields obtained during the photochemical oxidation of other aromatic compounds under similar conditions. In addition, a density of 1.35+/-0.04 g/cm3 for the secondary organic aerosol from the benzene photochemical oxidation in the presence of NOx has been determined through the simultaneous measurement of aerosol volume and aerosol mass using two independent measurement techniques. Comparing the results in the present work with previous findings underscores the strong influence that the NOx content in the system has on aerosol formation during the photochemical oxidation of aromatic hydrocarbons and the importance of performing experiments with NOx concentrations relevant to the atmosphere.

  10. Observations of lower-stratospheric ClONO2, HNO3, and aerosol by the UARS CLAES experiment between January 1992 and April 1993

    NASA Technical Reports Server (NTRS)

    Roche, A. E.; Kumer, J. B.; Mergenthaler, J. L.; Nightingale, R. W.; Uplinger, W. G.; Ely, G. A.; Potter, J. F.; Wuebbles, D. J.; Connell, P. S.; Kinnison, D. E.

    1994-01-01

    This paper discusses simultaneous measurements of stratospheric ClONO2, HNO3, temperature, and aerosol extinction coefficient by the Cryogenic Limb Array Etalon Spectrometer (CLAES) on the NASA Upper Atmosphere Research Satellite (UARS), obtained over the period 9 January 1992 through 23 April 1993. The discussion concentrates on the stratosphere region near 21 km of particular interest to heterogeneously driven ozone depletion. For periods between 12 June and 1 September 1992 at latitudes poleward of about 60 deg S, when temperatures were below type I polar stratospheric cloud (PSC) formation thresholds throughout the lower stratosphere, CLAES observed high levels of PSCs coincident with highly depleted fields of both HNO3 and ClONO2. By 17 September, the incidence of PSCs had greatly diminished in the lower stratosphere, but both CLONO2 and HNO3 remained highly depleted. These observations are consistent with the removal of gaseous HNO3 through the formation of nitric acid trihydrate (NAT) particles and the removal of ClONO2 through heterogeneous reactions on the particle surfaces. They also suggest substantial denitrification of the lower Antarctic vortex through sedimentation of PSC particles. In the Northern Hemisphere winter of 1992/93 far fewer PSCs were observed in the Arctic lower-stratosphere vortex, which had shorter periods and more localized regions of cold temperatures. Both HNO3 and ClONO2 maintained much higher levels inside the Arctic vortex than seen in the Antarctic throughout the winter/spring period. Following 28 February 1993 when Arctic vortex temperatures rose above 195 K, ClONO2 was observed in large quantities (greater than 2.1 ppbv near 21 km) inside the vortex. The persistence of relatively high levels of HNO3 inside the Arctic spring vortex compared with the low levels seen in the Antarctic spring vortex suggest a much lower level of denitrification in the Arctic.

  11. Aerosol chemical properties and related pollutants measured in Dongsha Island in the northern South China Sea during 7-SEAS/Dongsha Experiment

    NASA Astrophysics Data System (ADS)

    Chuang, Ming-Tung; Chang, Shuenn-Chin; Lin, Neng-Huei; Wang, Jia-Lin; Sheu, Guey-Rong; Chang, You-Jia; Lee, Chung-Te

    2013-10-01

    Aerosol observations were conducted at Dongsha Island in two batches from 19 to 23 March and 10 to 19 April 2010. Dongsha Island is located in a remote area over the northern South China Sea (SCS), distantly surrounded by southern China, Taiwan, the Philippines, and the Indochinese Peninsula. During the study period, the average PM10 and PM2.5 mass concentrations were 26.5 ± 19.4 and 12.6 ± 6.0 μg m-3, respectively. In particular, a daily PM10 concentration of 94.1 μg m-3 caused by a yellow-dust event originating from the Asian Continent was recorded on 21 March. Other than this event, the PM2.5 and PM10-2.5 daily levels were 7.1 ± 1.2 and 12.6 ± 5.0 μg m-3, respectively, on days without pollution from anthropogenic sources in the surrounding areas. Water-soluble ions (WSIs) were the predominant components that accounted for 58.7% ± 10.5% and 51.1% ± 7.2% of the PM10 and PM2.5 mass. The second most abundant component was carbonaceous content, which accounted for 9.5% ± 4.7% and 17.5% ± 5.3% of PM10 and PM2.5, respectively. SO42- was the most abundant PM2.5 WSI, whereas the Na+ and Cl- pair was the most abundant PM10-2.5 WSI. Based on the U.S. IMPROVE protocol, the resolved carbonaceous fractions were mainly distributed in PM2.5 and influenced by coal combustion, mobile vehicles, and biomass burning. Most of the resolved WSIs in particles were in the liquid phase due to the humid environment around the northern SCS.

  12. Improving Aerosol Transport to the Arctic in CAM5

    NASA Astrophysics Data System (ADS)

    Wang, H.; Easter, R. C.; Rasch, P.; Wang, M.; Liu, X.; Ghan, S.; Qian, Y.; Yoon, J.; Ma, P.; Vinoj, V.

    2011-12-01

    Of the many factors contributing to the rapid arctic climate change, arctic haze has been identified as a potentially important forcing agent. It has been well established that arctic aerosols largely originate from lower latitudes. Hence, the long-range atmospheric transport of aerosols to the Arctic is of great concern for studying arctic climate change. The treatment of aerosol and cloud processes has been substantially improved in the current version of the Community Atmosphere Model (CAM5) which is widely used in the research of aerosol effects on clouds and climate. However, like many other global models, the CAM5 produces a relatively poor simulation of arctic aerosols and clouds. For example, previous studies have shown that the standard version of CAM5 remarkably underpredicts arctic aerosol concentrations, particularly during the arctic haze season, compared to various measurements. In this study, we focus on improving processes associated with aerosol-cloud interactions, cloud microphysics and macrophysics, and aerosol emission, transformation, removal, and deposition that are key to determining the amount of aerosols reaching the Arctic. Sensitivity experiments are conducted to understand the role of each of the processes and to identify sources of uncertainties, and improvements are made to processes that are not well represented in the CAM5. The evaluation and improvement are guided by aerosol and cloud measurements together with process-oriented model results from the multi-scale aerosol-climate model (PNNL-MMF) that embeds a cloud-resolving model in each CAM5 grid column to explicitly represent convection and aerosol-cloud interactions. Results show that including black carbon (BC) aging process through a more complete 7-mode version of the aerosol module in CAM5 can substantially increase the amount of arctic BC, compared to simulations with the standard 3-mode version, but has minimal effect on other species such as dust and sulfate. Excessive mid

  13. Unspeciated organic emissions from combustion sources and their influence on the secondary organic aerosol budget in the United States

    EPA Science Inventory

    Secondary organic aerosol (SOA) formed from the atmospheric oxidation of nonmethane organic gases (NMOG) is a major contributor to atmospheric aerosol mass. Emissions and smog chamber experiments were performed to investigate SOA formation from gasoline vehicles, diesel vehicles,...

  14. Validation studies using multiwavelength Cryogenic Limb Array Etalon Spectrometer (CLAES) observations of stratospheric aerosol

    NASA Astrophysics Data System (ADS)

    Massie, Steven T.; Gille, John C.; Edwards, David P.; Bailey, Paul L.; Lyjak, Lawrence V.; Craig, Cheryl A.; Cavanaugh, Charles P.; Mergenthaler, John L.; Roche, Aidan E.; Kumer, John B.; Lambert, Alyn; Grainger, Roy G.; Rodgers, Clive D.; Taylor, Frederic W.; Russell, James M.; Park, Jae H.; Deshler, Terry; Hervig, Mark E.; Fishbein, Evan F.; Waters, Joe W.; Lahoz, William A.

    1996-04-01

    Validation studies of multiwavelength Cryogenic Limb Array Etalon Spectrometer (CLAES) observations of stratospheric aerosol are discussed. An error analysis of the CLAES aerosol extinction data is presented. Aerosol extinction precision values are estimated at latitudes and times at which consecutive Upper Atmosphere Research Satellite (UARS) orbits overlap. Comparisons of CLAES aerosol data with theoretical Mie calculations, based upon in situ particle size measurements at Laramie, Wyoming, are presented. CLAES aerosol data are also compared to scaled aerosol extinction measured by the Stratospheric Aerosol and Gas Experiment (SAGE II) and Atmospheric Trace Molecule Spectroscopy (ATMOS) experiments. Observed and calculated extinction spectra, from CLAES, Improved Stratospheric and Mesospheric Sounder (ISAMS), and Halogen Occultation Experiment (HALOE) data, are compared. CLAES extinction data have precisions between 10 and 25%, instrumental biases near 30%, and accuracies between 33 and 43%.

  15. Aqueous aerosol SOA formation: impact on aerosol physical properties.

    PubMed

    Woo, Joseph L; Kim, Derek D; Schwier, Allison N; Li, Ruizhi; McNeill, V Faye

    2013-01-01

    Organic chemistry in aerosol water has recently been recognized as a potentially important source of secondary organic aerosol (SOA) material. This SOA material may be surface-active, therefore potentially affecting aerosol heterogeneous activity, ice nucleation, and CCN activity. Aqueous aerosol chemistry has also been shown to be a potential source of light-absorbing products ("brown carbon"). We present results on the formation of secondary organic aerosol material in aerosol water and the associated changes in aerosol physical properties from GAMMA (Gas-Aerosol Model for Mechanism Analysis), a photochemical box model with coupled gas and detailed aqueous aerosol chemistry. The detailed aerosol composition output from GAMMA was coupled with two recently developed modules for predicting a) aerosol surface tension and b) the UV-Vis absorption spectrum of the aerosol, based on our previous laboratory observations. The simulation results suggest that the formation of oligomers and organic acids in bulk aerosol water is unlikely to perturb aerosol surface tension significantly. Isoprene-derived organosulfates are formed in high concentrations in acidic aerosols under low-NO(x) conditions, but more experimental data are needed before the potential impact of these species on aerosol surface tension may be evaluated. Adsorption of surfactants from the gas phase may further suppress aerosol surface tension. Light absorption by aqueous aerosol SOA material is driven by dark glyoxal chemistry and is highest under high-NO(x) conditions, at high relative humidity, in the early morning hours. The wavelength dependence of the predicted absorption spectra is comparable to field observations and the predicted mass absorption efficiencies suggest that aqueous aerosol chemistry can be a significant source of aerosol brown carbon under urban conditions. PMID:24601011

  16. Influence of Aerosols on Monsoon Circulation and Hydroclimate

    NASA Technical Reports Server (NTRS)

    Lau, William K.M.

    2007-01-01

    Long recognized as a major environmental hazard, aerosol is now known to have strong impacts on both regional and global water cycles and climate change. In the Asian monsoon regions, the response of the regional water cycle and climate to aerosol forcing is very complex, not only because of presence of diverse mix of aerosol species with vastly different radiative properties, but also because the monsoon is strongly influenced by ocean and land surface processes, land use, land change, as well as regional and global greenhouse warming effects. Thus, sorting out the impacts of aerosol forcing, and interaction with the monsoon water cycle is a very challenging problem. Up to now, besides the general notion that aerosols may significantly impact monsoon through altering large scale radiative heating gradients, there has been very little information regarding the specific signatures, and mechanisms of aerosol-monsoon water cycle interaction. In this talk, based on preliminary results from observations and climate model experiments, I will offer some insights into how aerosols may impact the Asian monsoon water cycle, in particular the effects of absorbing aerosols (dust and black carbon), and the role of the Tibetan Plateau. The influence of aerosol forcing relative to those due to sea surface temperature and land surface processes, and impact on potential predictability of the monsoon climate system will also be discussed.

  17. Influence of Aerosols on Monsoon Circulation and Hydroclimate

    NASA Technical Reports Server (NTRS)

    Lau, William K.

    2006-01-01

    Long recognized as a major environmental hazard, aerosol is now known to have strong impacts on both regional and global water cycles and climate change. In the Asian monsoon regions, the response of the regional water cycle and climate to aerosol forcing is very complex, not only because of presence of diverse mix of aerosol species with vastly different radiative properties, but also because the monsoon is strongly influenced by ocean and land surface processes, land use, land change, as well as regional and global greenhouse warming effects. Thus, sorting out the impacts of aerosol forcing, and interaction with the monsoon water cycle is a very challenging problem. Up to now, besides the general notion that aerosols may significantly impact monsoon through altering large scale radiative heating gradients, there has been very little information regarding the specific signatures, and mechanisms of aerosol-monsoon water cycle interaction. In this talk, based on preliminary results from observations and climate model experiments, I will offer some insights into how aerosols may impact the Asian monsoon water cycle, in particular the effects of absorbing aerosols (dust and black carbon), and the role of the Tibetan Plateau. The influence of aerosol forcing relative to those due to sea surface temperature and land surface processes, and impact on potential predictability of the monsoon climate system will also be discussed.

  18. Fine Mode Aerosol over the United Arab Emirates

    NASA Astrophysics Data System (ADS)

    Ross, K. E.; Piketh, S. J.; Reid, J. S.; Reid, E. A.

    2005-12-01

    The aerosol loading of the atmosphere over the Arabian Gulf region is extremely diverse and is composed not only of dust, but also of pollution that is derived largely from oil-related activities. Fine mode pollution particles are most efficient at scattering incoming solar radiation and have the potential to act as cloud condensation nuclei (CCN), and may therefore have implications for climate change. The smaller aerosols may also pose a health hazard if present in high concentrations. The United Arab Emirates Unified Aerosol Experiment (UAE2) was designed to investigate aerosol and meteorological characteristics over the region using ground-based, aircraft and satellite measurements, and was conducted in August and September 2004. Aerosol chemical composition has been obtained from filters that were collected at the site of the Mobile Atmospheric Aerosol and Radiation Characterization Observatory (MAARCO) on the coast of the UAE between Abu Dhabi and Dubai. Filter samples were also collected on an airborne platform in order to assess how aerosol chemical composition varies across the region and throughout the depth of the boundary layer. Results of the analysis of the PM2.5 coastal samples show that ammonium sulphate is the most prevalent constituent of the fine mode aerosol in the region (>50% of the mass), followed by organic matter, alumino-silicates, calcium carbonate and black carbon. Source apportionment indicates that most of the fine aerosol mass is derived from fossil fuel combustion, while mineral dust and local vehicle emissions also contribute to the fine aerosol loading. The organic carbon-to-total carbon ratio of the aerosol is 0.65, which is typical of fossil fuel combustion. The dominance of sulphates means that the fine mode aerosol in the region is probably responsible for a negative radiative forcing, and that the polluting emissions significantly elevate the concentration of CCN.

  19. Sugars in Antarctic aerosol

    NASA Astrophysics Data System (ADS)

    Barbaro, Elena; Kirchgeorg, Torben; Zangrando, Roberta; Vecchiato, Marco; Piazza, Rossano; Barbante, Carlo; Gambaro, Andrea

    2015-10-01

    The processes and transformations occurring in the Antarctic aerosol during atmospheric transport were described using selected sugars as source tracers. Monosaccharides (arabinose, fructose, galactose, glucose, mannose, ribose, xylose), disaccharides (sucrose, lactose, maltose, lactulose), alcohol-sugars (erythritol, mannitol, ribitol, sorbitol, xylitol, maltitol, galactitol) and anhydrosugars (levoglucosan, mannosan and galactosan) were measured in the Antarctic aerosol collected during four different sampling campaigns. For quantification, a sensitive high-pressure anion exchange chromatography was coupled with a single quadrupole mass spectrometer. The method was validated, showing good accuracy and low method quantification limits. This study describes the first determination of sugars in the Antarctic aerosol. The total mean concentration of sugars in the aerosol collected at the "Mario Zucchelli" coastal station was 140 pg m-3; as for the aerosol collected over the Antarctic plateau during two consecutive sampling campaigns, the concentration amounted to 440 and 438 pg m-3. The study of particle-size distribution allowed us to identify the natural emission from spores or from sea-spray as the main sources of sugars in the coastal area. The enrichment of sugars in the fine fraction of the aerosol collected on the Antarctic plateau is due to the degradation of particles during long-range atmospheric transport. The composition of sugars in the coarse fraction was also investigated in the aerosol collected during the oceanographic cruise.

  20. Studies of the aerosol indirect effect from sulfate and black carbon aerosols

    NASA Astrophysics Data System (ADS)

    Kristjánsson, Jón Egill

    2002-08-01

    The indirect effect of anthropogenic aerosols is investigated using the global climate model National Center for Atmospheric Research Community Climate Model Version 3 (NCAR CCM3). Two types of anthropogenic aerosols are considered, i.e., sulfate and black carbon aerosols. The concentrations and horizontal distributions of these aerosols were obtained from simulations with a life-cycle model incorporated into the global climate model. They are then combined with size-segregated background aerosols. The aerosol size distributions are subjected to condensation, coagulation, and humidity swelling. By making assumptions on supersaturation, we determine cloud droplet number concentrations in water clouds. Cloud droplet sizes and top of atmosphere (TOA) radiative fluxes are in good agreement with satellite observations. Both components of the indirect effect, i.e., the radius and lifetime effects, are computed as pure forcing terms. Using aerosol data for 2000 from the Intergovernmental Panel on Climate Change (IPCC), we find, globally averaged, a 5% decrease in cloud droplet radius and a 5% increase in cloud water path due to anthropogenic aerosols. The largest changes are found over SE Asia, followed by the North Atlantic, Europe, and the eastern United States. This is also the case for the radiative forcing (``indirect effect''), which has a global average of -1.8 W m-2. When the experiment is repeated using data for 2100 from the IPCC A2 scenario, an unchanged globally averaged radiative forcing is found, but the horizontal distribution has been shifted toward the tropics. Sensitivity experiments show that the radius effect is ~3 times as important as the lifetime effect and that black carbon only contributes marginally to the overall indirect effect.

  1. YAG aerosol lidar

    NASA Technical Reports Server (NTRS)

    Sullivan, R.

    1988-01-01

    The Global Atmospheric Backscatter Experiment (GLOBE) Mission, using the NASA DC-8 aircraft platform, is designed to provide the magnitude and statistical distribution of atmospheric backscatter cross section at lidar operating wavelengths. This is a fundamental parameter required for the Doppler lidar proposed to be used on a spacecraft platform for global wind field measurements. The prime measurements will be made by a CO2 lidar instrument in the 9 to 10 micron range. These measurements will be complemented with the Goddard YAG Aerosol Lidar (YAL) data in two wavelengths, 0.532 and 1.06 micron, in the visible and near-infrared. The YAL, is being designed to utilize as much existing hardware, as feasible, to minimize cost and reduce implementation time. The laser, energy monitor, telescope and detector package will be mounted on an optical breadboard. The optical breadboard is mounted through isolation mounts between two low boy racks. The detector package will utilize a photomultiplier tube for the 0.532 micron channel and a silicon avalanche photo detector (APD) for the 1.06 micron channel.

  2. The post-pinatubo evolution of stratospheric aerosol surface area density as inferred from SAGE 2

    NASA Technical Reports Server (NTRS)

    Poole, L. R.; Thomason, L. W.

    1994-01-01

    Following the eruption of Mount Pinatubo in June of 1991, the aerosol mass loading of the stratosphere increased from -1 Mt to approximately 30 Mt. This change in aerosol loading was responsible for numerous radiative and chemical changes observed within the stratosphere. As a result, the ability to quantify aerosol properties on a global basis during this period is important. Aerosol surface area density is a critical parameter in governing the rates of heterogeneous reactions, such as ClONO2 plus H2O yields HNO3 plus HOCl, which influence the stratospheric abundance of ozone. Following the eruption of Mt. Pinatubo, measurements by the Stratospheric Aerosol and Gas Experiment (SAGE 2) indicated that the stratospheric aerosol surface area density increased by as much as a factor of 100. Using SAGE 2 multi-wavelength aerosol extinction data, aerosol surface area density as well as mass are derived for the period following the eruption of Mt. Pinatubo through the present.

  3. THERMAL PROPERTIES OF SECONDARY ORGANIC AEROSOLS

    EPA Science Inventory

    Volume concentrations of steady-state secondary organic aerosol (SOA) were measured in several hydrocarbon/NOx irradiation experiments. These measurements were used to estimate the thermal behavior of the particles that may be formed in the atmosphere. These laborator...

  4. Evaluation of liquid aerosol transport through porous media.

    PubMed

    Hall, R; Murdoch, L; Falta, R; Looney, B; Riha, B

    2016-07-01

    Application of remediation methods in contaminated vadose zones has been hindered by an inability to effectively distribute liquid- or solid-phase amendments. Injection as aerosols in a carrier gas could be a viable method for achieving useful distributions of amendments in unsaturated materials. The objectives of this work were to characterize radial transport of aerosols in unsaturated porous media, and to develop capabilities for predicting results of aerosol injection scenarios at the field-scale. Transport processes were investigated by conducting lab-scale injection experiments with radial flow geometry, and predictive capabilities were obtained by developing and validating a numerical model for simulating coupled aerosol transport, deposition, and multi-phase flow in porous media. Soybean oil was transported more than 2m through sand by injecting it as micron-scale aerosol droplets. Oil saturation in the sand increased with time to a maximum of 0.25, and decreased with radial distance in the experiments. The numerical analysis predicted the distribution of oil saturation with only minor calibration. The results indicated that evolution of oil saturation was controlled by aerosol deposition and subsequent flow of the liquid oil, and simulation requires including these two coupled processes. The calibrated model was used to evaluate field applications. The results suggest that amendments can be delivered to the vadose zone as aerosols, and that gas injection rate and aerosol particle size will be important controls on the process.

  5. Evaluation of liquid aerosol transport through porous media

    NASA Astrophysics Data System (ADS)

    Hall, R.; Murdoch, L.; Falta, R.; Looney, B.; Riha, B.

    2016-07-01

    Application of remediation methods in contaminated vadose zones has been hindered by an inability to effectively distribute liquid- or solid-phase amendments. Injection as aerosols in a carrier gas could be a viable method for achieving useful distributions of amendments in unsaturated materials. The objectives of this work were to characterize radial transport of aerosols in unsaturated porous media, and to develop capabilities for predicting results of aerosol injection scenarios at the field-scale. Transport processes were investigated by conducting lab-scale injection experiments with radial flow geometry, and predictive capabilities were obtained by developing and validating a numerical model for simulating coupled aerosol transport, deposition, and multi-phase flow in porous media. Soybean oil was transported more than 2 m through sand by injecting it as micron-scale aerosol droplets. Oil saturation in the sand increased with time to a maximum of 0.25, and decreased with radial distance in the experiments. The numerical analysis predicted the distribution of oil saturation with only minor calibration. The results indicated that evolution of oil saturation was controlled by aerosol deposition and subsequent flow of the liquid oil, and simulation requires including these two coupled processes. The calibrated model was used to evaluate field applications. The results suggest that amendments can be delivered to the vadose zone as aerosols, and that gas injection rate and aerosol particle size will be important controls on the process.

  6. Parameter sensitivity study of Arctic aerosol vertical distribution in CAM5

    NASA Astrophysics Data System (ADS)

    Jiao, C.; Flanner, M.

    2015-12-01

    Arctic surface temperature response to light-absorbing aerosols (black carbon, brown carbon and dust) depends strongly on their vertical distributions. Improving model simulations of three dimensional aerosol fields in the remote Arctic region will therefore lead to improved projections of the climate change caused by aerosol emissions. In this study, we investigate how different physical parameterizations in the Community Atmosphere Model version 5 (CAM5) influence the simulated vertical distribution of Arctic aerosols. We design experiments to test the sensitivity of the simulated aerosol fields to perturbations of selected aerosol process-related parameters in the Modal Aerosol Module with seven lognormal modes (MAM7), such as those govern aerosol aging, in-cloud and below-cloud scavenging, aerosol hygroscopicity and so on. The simulations are compared with observed aerosol vertical distributions and total optical depth to assess model performance and quantify uncertainties associated with these model parameterizations. Observations applied here include Arctic aircraft measurements of black carbon and sulfate vertical profiles, along with Aerosol Robotic Network (AERONET) optical depth measurements. We also assess the utility of using High Spectral Resolution Lidar (HSRL) measurements from the ARM Barrow site to infer vertical profiles of aerosol extinction. The sensitivity study explored here will provide guidance for optimizing global aerosol simulations.

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

    NASA Technical Reports Server (NTRS)

    Thomason, L. W.

    2012-01-01

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

  8. Organic aerosol formation in citronella candle plumes

    PubMed Central

    Bothe, Melanie

    2010-01-01

    Citronella candles are widely used as insect repellants, especially outdoors in the evening. Because these essential oils are unsaturated, they have a unique potential to form secondary organic aerosol (SOA) via reaction with ozone, which is also commonly elevated on summer evenings when the candles are often in use. We investigated this process, along with primary aerosol emissions, by briefly placing a citronella tealight candle in a smog chamber and then adding ozone to the chamber. In repeated experiments, we observed rapid and substantial SOA formation after ozone addition; this process must therefore be considered when assessing the risks and benefits of using citronella candle to repel insects. PMID:20700379

  9. Volcanic Aerosol Radiative Properties

    NASA Technical Reports Server (NTRS)

    Lacis, Andrew

    2015-01-01

    Large sporadic volcanic eruptions inject large amounts of sulfur bearing gases into the stratosphere which then get photochemically converted to sulfuric acid aerosol droplets that exert a radiative cooling effect on the global climate system lasting for several years.

  10. Palaeoclimate: Aerosols and rainfall

    NASA Astrophysics Data System (ADS)

    Partin, Jud

    2015-03-01

    Instrumental records have hinted that aerosol emissions may be shifting rainfall over Central America southwards. A 450-year-long precipitation reconstruction indicates that this shift began shortly after the Industrial Revolution.

  11. Evaluation of one-dimensional and two-dimensional volatility basis sets in simulating the aging of secondary organic aerosol with smog-chamber experiments.

    PubMed

    Zhao, Bin; Wang, Shuxiao; Donahue, Neil M; Chuang, Wayne; Hildebrandt Ruiz, Lea; Ng, Nga L; Wang, Yangjun; Hao, Jiming

    2015-02-17

    We evaluate the one-dimensional volatility basis set (1D-VBS) and two-dimensional volatility basis set (2D-VBS) in simulating the aging of SOA derived from toluene and α-pinene against smog-chamber experiments. If we simulate the first-generation products with empirical chamber fits and the subsequent aging chemistry with a 1D-VBS or a 2D-VBS, the models mostly overestimate the SOA concentrations in the toluene oxidation experiments. This is because the empirical chamber fits include both first-generation oxidation and aging; simulating aging in addition to this results in double counting of the initial aging effects. If the first-generation oxidation is treated explicitly, the base-case 2D-VBS underestimates the SOA concentrations and O:C increase of the toluene oxidation experiments; it generally underestimates the SOA concentrations and overestimates the O:C increase of the α-pinene experiments. With the first-generation oxidation treated explicitly, we could modify the 2D-VBS configuration individually for toluene and α-pinene to achieve good model-measurement agreement. However, we are unable to simulate the oxidation of both toluene and α-pinene with the same 2D-VBS configuration. We suggest that future models should implement parallel layers for anthropogenic (aromatic) and biogenic precursors, and that more modeling studies and laboratory research be done to optimize the "best-guess" parameters for each layer.

  12. Evaluation of one-dimensional and two-dimensional volatility basis sets in simulating the aging of secondary organic aerosol with smog-chamber experiments.

    PubMed

    Zhao, Bin; Wang, Shuxiao; Donahue, Neil M; Chuang, Wayne; Hildebrandt Ruiz, Lea; Ng, Nga L; Wang, Yangjun; Hao, Jiming

    2015-02-17

    We evaluate the one-dimensional volatility basis set (1D-VBS) and two-dimensional volatility basis set (2D-VBS) in simulating the aging of SOA derived from toluene and α-pinene against smog-chamber experiments. If we simulate the first-generation products with empirical chamber fits and the subsequent aging chemistry with a 1D-VBS or a 2D-VBS, the models mostly overestimate the SOA concentrations in the toluene oxidation experiments. This is because the empirical chamber fits include both first-generation oxidation and aging; simulating aging in addition to this results in double counting of the initial aging effects. If the first-generation oxidation is treated explicitly, the base-case 2D-VBS underestimates the SOA concentrations and O:C increase of the toluene oxidation experiments; it generally underestimates the SOA concentrations and overestimates the O:C increase of the α-pinene experiments. With the first-generation oxidation treated explicitly, we could modify the 2D-VBS configuration individually for toluene and α-pinene to achieve good model-measurement agreement. However, we are unable to simulate the oxidation of both toluene and α-pinene with the same 2D-VBS configuration. We suggest that future models should implement parallel layers for anthropogenic (aromatic) and biogenic precursors, and that more modeling studies and laboratory research be done to optimize the "best-guess" parameters for each layer. PMID:25581402

  13. Aerosol dynamics in ship tracks

    NASA Astrophysics Data System (ADS)

    Russell, Lynn M.; Seinfeld, John H.; Flagan, Richard C.; Ferek, Ronald J.; Hegg, Dean A.; Hobbs, Peter V.; Wobrock, Wolfram; Flossmann, Andrea I.; O'Dowd, Colin D.; Nielsen, Kurt E.; Durkee, Phillip A.

    1999-01-01

    Ship tracks are a natural laboratory to isolate the effect of anthropogenic aerosol emissions on cloud properties. The Monterey Area Ship Tracks (MAST) experiment in the Pacific Ocean west of Monterey, California, in June 1994, provides an unprecedented data set for evaluating our understanding of the formation and persistence of the anomalous cloud features that characterize ship tracks. The data set includes conditions in which the marine boundary layer is both clean and continentally influenced. Two case studies during the MAST experiment are examined with a detailed aerosol microphysical model that considers an external mixture of independent particle populations. The model allows tracking individual particles through condensational and coagulational growth to identify the source of cloud condensation nuclei (CCN). In addition, a cloud microphysics model was employed to study specific effects of precipitation. Predictions and observations reveal important differences between clean (particle concentrations below 150 cm-3) and continentally influenced (particle concentrations above 400 cm-3) background conditions: in the continentally influenced conditions there is a smaller change in the cloud effective radius, drop number and liquid water content in the ship track relative to the background than in the clean marine case. Predictions of changes in cloud droplet number concentrations and effective radii are consistent with observations although there is significant uncertainty in the absolute concentrations due to a lack of measurements of the plume dilution. Gas-to-particle conversion of sulfur species produced by the combustion of ship fuel is predicted to be important in supplying soluble aerosol mass to combustion-generated particles, so as to render them available as CCN. Studies of the impact of these changes on the cloud's potential to precipitate concluded that more complex dynamical processes must be represented to allow sufficiently long drop

  14. Emergency Protection from Aerosols

    SciTech Connect

    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.

  15. Emergency protection from aerosols

    SciTech Connect

    Cristy, G.A.; Chester, C.V.

    1981-07-01

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

  16. Monodisperse aerosol generator

    DOEpatents

    Ortiz, Lawrence W.; Soderholm, Sidney C.

    1990-01-01

    An aerosol generator is described which is capable of producing a monodisperse aerosol within narrow limits utilizing an aqueous solution capable of providing a high population of seed nuclei and an organic solution having a low vapor pressure. The two solutions are cold nebulized, mixed, vaporized, and cooled. During cooling, particles of the organic vapor condense onto the excess seed nuclei, and grow to a uniform particle size.

  17. MISR Aerosol Typing

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph A.

    2014-01-01

    AeroCom is an open international initiative of scientists interested in the advancement of the understanding of global aerosol properties and aerosol impacts on climate. A central goal is to more strongly tie and constrain modeling efforts to observational data. A major element for exchanges between data and modeling groups are annual meetings. The meeting was held September 20 through October 2, 1014 and the organizers would like to post the presentations.

  18. Black carbon in aerosol during BIBLE B

    NASA Astrophysics Data System (ADS)

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

    2002-02-01

    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.

  19. Black carbon in aerosol during BIBLE B

    NASA Astrophysics Data System (ADS)

    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.

  20. RACORO aerosol data processing

    SciTech Connect

    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.

  1. Retrieving the Vertical Structure of the Effective Aerosol Complex Index of Refraction from a Combination of Aerosol in Situ and Remote Sensing Measurements During TARFOX

    NASA Technical Reports Server (NTRS)

    Redemann, J.; Turco, R. P.; Liou, K. N.; Russell, P. B.; Bergstrom, R. W.; Schmid, B.; Livingston, J. M.; Hobbs, P. V.; Hartley, W. S.; Ismail, S.; Ferrare, R. A.; Browell, E. V.

    2000-01-01

    The largest uncertainty in estimates of the effects of atmospheric aerosols on climate stems from uncertainties in the determination of their microphysical properties, including the aerosol complex index of refraction, which in turn determines their optical properties. A novel technique is used to estimate the aerosol complex index of refraction in distinct vertical layers from a combination of aerosol in situ size distribution and remote sensing measurements during the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX). In particular, aerosol backscatter measurements using the NASA Langley LASE (Lidar Atmospheric Sensing Experiment) instrument and in situ aerosol size distribution data are utilized to derive vertical profiles of the "effective" aerosol complex index of refraction at 815 nm (i.e., the refractive index that would provide the same backscatter signal in a forward calculation on the basis of the measured in situ particle size distributions for homogeneous, spherical aerosols). A sensitivity study shows that this method yields small errors in the retrieved aerosol refractive indices, provided the errors in the lidar-derived aerosol backscatter are less than 30% and random in nature. Absolute errors in the estimated aerosol refractive indices are generally less than 0.04 for the real part and can be as much as 0.042 for the imaginary part in the case of a 30% error in the lidar-derived aerosol backscatter. The measurements of aerosol optical depth from the NASA Ames Airborne Tracking Sunphotometer (AATS-6) are successfully incorporated into the new technique and help constrain the retrieved aerosol refractive indices. An application of the technique to two TARFOX case studies yields the occurrence of vertical layers of distinct aerosol refractive indices. Values of the estimated complex aerosol refractive index range from 1.33 to 1.45 for the real part and 0.001 to 0.008 for the imaginary part. The methodology devised in this study

  2. Impact of anthropogenic aerosols on Indian summer monsoon

    SciTech Connect

    Wang, Chien; Kim, Dongchul; Ekman, Annica; Barth, Mary; Rasch, Philip J.

    2009-11-05

    Using an interactive aerosol-climate model we find that absorbing anthropogenic aerosols, whether coexisting with scattering aerosols or not, can significantly affect the Indian summer monsoon system. We also show that the influence is reflected in a perturbation to the moist static energy in the sub-cloud layer, initiated as a heating by absorbing aerosols to the planetary boundary layer. The perturbation appears mostly over land, extending from just north of the Arabian Sea to northern India along the southern slope of the Tibetan Plateau. As a result, during the summer monsoon season, modeled convective precipitation experiences a clear northward shift, coincidently in agreement with observed monsoon precipitation changes in recent decades particularly during the onset season. We demonstrate that the sub-cloud layer moist static energy is a useful quantity for determining the impact of aerosols on the northward extent and to a certain degree the strength of monsoon convection.

  3. A study of remotely sensed aerosol properties from ground-based sun and sky scanning radiometers

    NASA Astrophysics Data System (ADS)

    Giles, David M.

    Aerosol particles impact human health by degrading air quality and affect climate by heating or cooling the atmosphere. The Indo-Gangetic Plain (IGP) of Northern India, one of the most populous regions in the world, produces and is impacted by a variety of aerosols including pollution, smoke, dust, and mixtures of them. The NASA Aerosol Robotic Network (AERONET) mesoscale distribution of Sun and sky-pointing instruments in India was established to measure aerosol characteristics at sites across the IGP and around Kanpur, India, a large urban and industrial center in the IGP, during the 2008 pre-monsoon (April-June). This study focused on detecting spatial and temporal variability of aerosols, validating satellite retrievals, and classifying the dominant aerosol mixing states and origins. The Kanpur region typically experiences high aerosol loading due to pollution and smoke during the winter and high aerosol loading due to the addition of dust to the pollution and smoke mixture during the pre-monsoon. Aerosol emissions in Kanpur likely contribute up to 20% of the aerosol loading during the pre-monsoon over the IGP. Aerosol absorption also increases significantly downwind of Kanpur indicating the possibility of the black carbon emissions from aerosol sources such as coal-fired power plants and brick kilns. Aerosol retrievals from satellite show a high bias when compared to the mesoscale distributed instruments around Kanpur during the pre-monsoon with few high quality retrievals due to imperfect aerosol type and land surface characteristic assumptions. Aerosol type classification using the aerosol absorption, size, and shape properties can identify dominant aerosol mixing states of absorbing dust and black carbon particles. Using 19 long-term AERONET sites near various aerosol source regions (Dust, Mixed, Urban/Industrial, and Biomass Burning), aerosol absorption property statistics are expanded upon and show significant differences when compared to previous work

  4. Indirect and Semi-Direct Aerosol Campaign: The Impact of Arctic Aerosols on Clouds

    SciTech Connect

    McFarquhar, Greg; Ghan, Steven J.; Verlinde, J.; Korolev, Alexei; Strapp, J. Walter; Schmid, Beat; Tomlinson, Jason M.; Wolde, Mengistu; Brooks, Sarah D.; Cziczo, Daniel J.; Dubey, Manvendra K.; Fan, Jiwen; Flynn, Connor J.; Gultepe, Ismail; Hubbe, John M.; Gilles, Mary K.; Laskin, Alexander; Lawson, Paul; Leaitch, W. R.; Liu, Peter S.; Liu, Xiaohong; Lubin, Dan; Mazzoleni, Claudio; Macdonald, A. M.; Moffet, Ryan C.; Morrison, H.; Ovchinnikov, Mikhail; Shupe, Matthew D.; Turner, David D.; Xie, Shaocheng; Zelenyuk, Alla; Bae, Kenny; Freer, Matthew; Glen, Andrew

    2011-02-01

    A comprehensive dataset of microphysical and radiative properties of aerosols and clouds in the arctic boundary layer in the vicinity of Barrow, Alaska was collected in April 2008 during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) sponsored by the Department of Energy Atmospheric Radiation Measurement (ARM) and Atmospheric Science Programs. The primary aim of ISDAC was to examine indirect effects of aerosols on clouds that contain both liquid and ice water. The experiment utilized the ARM permanent observational facilities at the North Slope of Alaska (NSA) in Barrow. These include a cloud radar, a polarized micropulse lidar, and an atmospheric emitted radiance interferometer as well as instruments specially deployed for ISDAC measuring aerosol, ice fog, precipitation and spectral shortwave radiation. The National Research Council of Canada Convair-580 flew 27 sorties during ISDAC, collecting data using an unprecedented 42 cloud and aerosol instruments for more than 100 hours on 12 different days. Data were obtained above, below and within single-layer stratus on 8 April and 26 April 2008. These data enable a process-oriented understanding of how aerosols affect the microphysical and radiative properties of arctic clouds influenced by different surface conditions. Observations acquired on a heavily polluted day, 19 April 2008, are enhancing this understanding. Data acquired in cirrus on transit flights between Fairbanks and Barrow are improving our understanding of the performance of cloud probes in ice. Ultimately the ISDAC data will be used to improve the representation of cloud and aerosol processes in models covering a variety of spatial and temporal scales, and to determine the extent to which long-term surface-based measurements can provide retrievals of aerosols, clouds, precipitation and radiative heating in the Arctic.

  5. Radiative Impacts of Elevated Aerosol Layers from Different Origins

    NASA Astrophysics Data System (ADS)

    Sauer, D. N.; Weinzierl, B.; Gasteiger, J.; Heimerl, K.

    2014-12-01

    Aerosol particles are omnipresent in the Earth's atmosphere and have important impacts on weather and climate by their effects on the atmospheric radiative balance. With the advent of more and more sophisticated representations of atmospheric processes in earth system models, the lack of reliable input data on aerosols leads to significant uncertainties in the prediction of future climate scenarios. In recent years large discrepancies in radiative forcing estimates from aerosol layers in modeling studies have been revealed emphasizing the need for detailed and systematic observations of aerosols. Airborne in-situ measurements represent an important pillar for validating both model results and retrievals of aerosol distributions and properties from remote sensing methods on global scales. However, detailed observations are challenging and therefore are subject to substantial uncertainties themselves. Here we use data from airborne in-situ measurements of elevated aerosol layers from various field experiments in different regions of the world. The data set includes Saharan mineral dust layers over Africa, the Atlantic Ocean and the Caribbean from the SALTRACE and the SAMUM campaigns as well as long-range transported biomass burning aerosol layers from wild fires in the Sahel region and North America measured over the tropical Atlantic Ocean, Europe and the Arctic detected during SAMUM2, CONCERT2011, DC3 and ACCESS 2012. We aim to characterize the effects of the measured aerosol layers, in particular with respect to ageing, mixing state and vertical structure, on the overall atmospheric radiation budget as well as local heating and cooling rates. We use radiative transfer simulations of short and long-wave radiation and aerosol optical properties derived in a consistent way from the in-situ observations of microphysical properties using T-matrix calculations. The results of this characterization will help to improve the parameterization of the effects of elevated

  6. Retrieval of stratospheric aerosol size distributions and integral properties from simulated lidar backscatter measurements.

    PubMed

    Yue, G K

    2000-10-20

    A new approach for retrieving aerosol properties from extinction spectra is extended to retrieve aerosol properties from lidar backscatter measurements. In this method it is assumed that aerosol properties are expressed as a linear combination of backscatters at three or fewer wavelengths commonly used in lidar measurements. The coefficients in the weighted linear combination are obtained by minimization of the retrieval error averaged for a set of testing size distributions. The formulas can be used easily by investigators to retrieve aerosol properties from lidar backscatter measurements such as the Lidar In-Space Technology Experiment and Pathfinder Instruments for Clouds and Aerosols Spaceborne Observations.

  7. A diagnostic stratospheric aerosol size distribution inferred from SAGE II measurements

    NASA Technical Reports Server (NTRS)

    Thomason, Larry W.

    1991-01-01

    An aerosol size distribution model for the stratosphere is inferred based on 5 years of Stratospheric Aerosol and Gas Experiment (SAGE) II measurements of multispectral aerosol and water vapor extinction. The SAGE II aerosol and water vapor extinction data strongly suggest that there is a critical particle radius below which there is a relatively weak dependence of particle number density with size and above which there are few, if any, particles. A segmented power law model, as a simple representation of this dependence, is used in theoretical calculations and intercomparisons with a variety of aerosol measurements including dustsondes, longwave lidar, and wire impactors and shows a consistently good agreement.

  8. WRF-Chem simulations of aerosols and anthropogenic aerosol radiative forcing in East Asia

    NASA Astrophysics Data System (ADS)

    Gao, Yi; Zhao, Chun; Liu, Xiaohong; Zhang, Meigen; Leung, L. Ruby

    2014-08-01

    This study aims to provide a first comprehensive evaluation of WRF-Chem for modeling aerosols and anthropogenic aerosol radiative forcing (RF, including direct, semi-direct and indirect forcing) over East Asia. Several numerical experiments were conducted from November 2007 to December 2008. Comparison between model results and observations shows that the model can generally reproduce the observed spatial distributions of aerosol concentration, aerosol optical depth (AOD) and single scattering albedo (SSA) from measurements at many sites, including the relatively higher aerosol concentration and AOD over East China and the relatively lower AOD over Southeast Asia, Korea, and Japan. The model also depicts the seasonal variation and transport of pollutions over East Asia. Particulate matter of 10 μm or less in the aerodynamic diameter (PM10), black carbon (BC), sulfate (SO42-), nitrate (NO3-) and ammonium (NH4+) concentrations are higher in spring than other seasons in Japan, which indicates the possible influence of pollutant transport from polluted area of East Asia. The model underestimates SO42- and organic carbon (OC) concentrations over mainland China by about a factor of 2, while overestimates NO3- concentration in autumn along the Yangtze River. The model captures the dust events at the Zhangye site in the semi-arid region of China. AOD is high over Southwest and Central China in winter and spring and over North China in winter, spring and summer while is low over South China in summer due to monsoon precipitation. SSA is lowest in winter and highest in summer. Anthropogenic aerosol RF is estimated to range from -5 to -20 W m-2 over land and -20 to -40 W m-2 over adjacent oceans at the top of atmosphere (TOA), 5-30 W m-2 in the atmosphere (ATM) and -15 to -40 W m-2 at the bottom (BOT). The warming effect of anthropogenic aerosol in ATM results from BC aerosol while the negative aerosol RF at TOA is caused by scattering aerosols such as SO42-, NO3- and NH4

  9. Impacts of East Asian aerosols on the Asian monsoon

    NASA Astrophysics Data System (ADS)

    Bartlett, Rachel; Bollasina, Massimo; Booth, Ben; Dunstone, Nick; Marenco, Franco

    2016-04-01

    Over recent decades, aerosol emissions from Asia have increased rapidly. Aerosols are able to alter radiative forcing and regional hydroclimate through direct and indirect effects. Large emissions within the geographical region of the Asian monsoon have been found to impact upon this vital system and have been linked to observed drying trends. The interconnected nature of smaller regional monsoon components (e.g. the Indian monsoon and East Asian monsoon) presents the possibility that aerosol sources could have far-reaching impacts. Future aerosol emissions are uncertain and may continue to dominate regional impacts on the Asian monsoon. Standard IPCC future emissions scenarios do not take a broad sample of possible aerosol pathways. We investigate the sensitivity of the Asian monsoon to East Asian aerosol emissions. Experiments carried out with HadGEM2-ES use three time-evolving future anthropogenic aerosol emissions scenarios with similar time-evolving greenhouse gases. We find a wetter summer over southern China and the Indochina Peninsula associated with increased sulfate aerosol over China. The southern-flood-northern-drought pattern seen in observations is reflected in these results. India is found to be drier in the summer overall, although wetter in June. These precipitation changes are linked to the increase in sulfate through the alteration of large scale dynamics. Sub-seasonal changes are also seen, with an earlier withdrawal of the monsoon over East Asia.

  10. It's a Sooty Problem: Black Carbon and Aerosols from Space

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram J.

    2005-01-01

    Our knowledge of atmospheric aerosols (smoke, pollution, dust or sea salt particles, small enough to be suspended in the air), their evolution, composition, variability in space and time and interaction with solar radiation, clouds and precipitation is lacking despite decades of research. Just recently we recognized that understanding the global aerosol system is fundamental for progress in climate change and hydrological cycle research. While a single instrument was used to demonstrate 50 yrs ago that the global CO2 levels are rising, posing thread to our climate, we need an may of satellites, surface networks of radiometers, elaborated laboratory and field experiments coupled with chemical transport models to understand the global aerosol system. This complexity of the aerosol problem results from their short lifetime (1 week), variability of the chemical composition and complex chemical and physical processes in the atmosphere. The result is a heterogeneous distribution of aerosol and their properties. The new generation of satellites and surface networks of radiometers provides exciting opportunities to measure the aerosol properties and their interaction with clouds and climate. However farther development in the satellite capability, aerosol chemical models and climate models is needed to fully decipher the aerosol secrets with accuracy required to predict future climates.

  11. Copper aerosols inhibit phytoplankton growth in the Mediterranean Sea

    PubMed Central

    Jordi, Antoni; Basterretxea, Gotzon; Tovar-Sánchez, Antonio; Alastuey, Andrés; Querol, Xavier

    2012-01-01

    Aerosol deposition plays an important role in climate and biogeochemical cycles by supplying nutrients to the open ocean, in turn stimulating ocean productivity and carbon sequestration. Aerosol particles also contain elements such as copper (Cu) that are essential in trace amounts for phytoplankton physiology but that can be toxic at high concentrations. Although the toxicity of Cu associated with aerosols has been demonstrated in bioassay experiments, extrapolation of these laboratory results to natural conditions is not straightforward. This study provides observational evidence of the negative effect of aerosols containing high Cu concentrations on marine phytoplankton over a vast region of the western Mediterranean Sea. Direct aerosol measurements were combined with satellite observations, resulting in the detection of significant declines in phytoplankton biomass after atmospheric aerosol events characterized by high Cu concentrations. The declines were more evident during summer, when nanoflagellates predominate in the phytoplankton population and stratification and oligotrophic conditions prevail in the study region. Together with previous findings concerning atmospheric Cu deposition, these results demonstrate that the toxicity of Cu-rich aerosols can involve large areas of the world’s oceans. Moreover, they highlight the present vulnerability of oceanic ecosystems to Cu-rich aerosols of anthropogenic origins. Because anthropogenic emissions are increasing, large-scale negative effects on marine ecosystems can be anticipated. PMID:23236141

  12. SAGE II aerosol data validation and initial data use - An introduction and overview

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Mccormick, M. P.

    1989-01-01

    The process of validating data from the Stratospheric Aerosol and Gas Experiment (SAGE) II and the initial use of the validated data are reviewed. The instruments developed for the SAGE II, the influence of the eruption of El Chichon on the global stratospheric aerosol, and various data validation experiments are discussed. Consideration is given to methods for deriving aerosol physical and optical properties from SAGE II extinction data and for inferring particle size distribution moments from SAGE II spectral extinction values.

  13. Airborne High Spectral Resolution Lidar Aerosol Measurements during MILAGRO and TEXAQS/GOMACCS

    NASA Technical Reports Server (NTRS)

    Ferrare, Richard; Hostetler, Chris; Hair, John; Cook Anthony; Harper, David; Burton, Sharon; Clayton, Marian; Clarke, Antony; Russell, Phil; Redemann, Jens

    2007-01-01

    Two1 field experiments conducted during 2006 provided opportunities to investigate the variability of aerosol properties near cities and the impacts of these aerosols on air quality and radiative transfer. The Megacity Initiative: Local and Global Research Observations (MILAGRO) /Megacity Aerosol Experiment in Mexico City (MAX-MEX)/Intercontinental Chemical Transport Experiment-B (INTEX-B) joint experiment conducted during March 2006 investigated the evolution and transport of pollution from Mexico City. The Texas Air Quality Study (TEXAQS)/Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) (http://www.al.noaa.gov/2006/) conducted during August and September 2006 investigated climate and air quality in the Houston/Gulf of Mexico region. During both missions, the new NASA Langley airborne High Spectral Resolution Lidar (HSRL) was deployed on the NASA Langley B200 King Air aircraft and measured profiles of aerosol extinction, backscattering, and depolarization to: 1) characterize the spatial and vertical distributions of aerosols, 2) quantify aerosol extinction and optical thickness contributed by various aerosol types, 3) investigate aerosol variability near clouds, 4) evaluate model simulations of aerosol transport, and 5) assess aerosol optical properties derived from a combination of surface, airborne, and satellite measurements.

  14. Climate effects of anthropogenic aerosols over East Asia based on modeling study

    NASA Astrophysics Data System (ADS)

    Mukai, Makiko

    The increasing emission of anthropogenic aerosols causes serious air pollution episodes and various effects on the climate by the aerosols interacting with the radiation budget by directly absorbing and scattering the solar radiation, and by them indirectly modifying the optical properties and lifetimes of clouds. In East Asia anthropogenic aerosol concentrations are rapidly increasing. It is therefore necessary to evaluate the sensitivity of anthropogenic aerosols upon the radiative forcing in this region. For this purpose we utilize an atmospheric general circulation model (AGCM) with an aerosol transport and radiation model and an ocean mixed-layer model. The model in this study was a three-dimensional aerosol transport-radiation model (SPRINTARS), driven by the AGCM developed by CCSR (Center for Climate System Research), NIES (National Institute for Environmental Studies), and FRCGC (Frontier Research Center for Global Change). This model incorporates sulfate, carbonaceous, sea salt, and mineral dust aerosols, the first three of which are assumed to acts as cloud condensation nuclei that generate cloud droplets whose number increases with the number of nuclei. We assumed sulfate and carbonaceous aerosol from fuel burning for anthropogenic aerosol. And the model simulations of equilibrium experiments were performed to investigate the impact of anthropogenic aerosols based on present-day emission data and the preindustrial-era emission data. Our simulation results showed that copious anthropogenic aerosol loading causes significant decrease in the surface downward shortwave radiation flux (SDSWRF), which indicates that a direct effect of aerosols has the greatest influence on the surface radiation. It is found from our model simulations that low-level clouds increase but convective clouds decrease due to reduced convective activity caused by surface cooling when anthropogenic aerosol increases. It was also found that the contributions of aerosols to the radiation

  15. Retrieving the Vertical Structure of the Effective Aerosol Complex Index of Refraction from a Combination of Aerosol in Situ and Remote Sensing Measurements During TARFOX

    NASA Technical Reports Server (NTRS)

    Redemann, J.; Turco, R. P.; Liou, K. N.; Russell, P. B.; Bergstrom, R. W.; Schmid, B.; Livingston, J. M.; Hobbs, P. V.; Hartley, W. S.; Ismail, S.

    2000-01-01

    The largest uncertainty in estimates of the effects of atmospheric aerosols on climate stems from uncertainties in the determination of their microphysical properties, including the aerosol complex index of refraction, which in turn determines their optical properties. A novel technique is used to estimate the aerosol complex index of refraction in distinct vertical layers from a combination of aerosol in situ size distribution and remote sensing measurements during the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX). In particular, aerosol backscatter measurements using the NASA Langley LASE (Lidar Atmospheric Sensing Experiment) instrument and in situ aerosol size distribution data are utilized to derive vertical profiles of the 'effective' aerosol complex index of refraction at 815 nm (i.e., the refractive index that would provide the same backscatter signal in a forward calculation on the basis of the measured in situ particle size distributions for homogeneous, spherical aerosols). A sensitivity study shows that this method yields small errors in the retrieved aerosol refractive indices, provided the errors in the lidar derived aerosol backscatter are less than 30% and random in nature. Absolute errors in the estimated aerosol refractive indices are generally less than 0.04 for the real part and can be as much as 0.042 for the imaginary part in the case of a 30% error in the lidar-derived aerosol backscatter. The measurements of aerosol optical depth from the NASA Ames Airborne Tracking Sunphotometer (AATS-6) are successfully incorporated into the new technique and help constrain the retrieved aerosol refractive indices. An application of the technique to two TARFOX case studies yields the occurrence of vertical layers of distinct aerosol refractive indices. Values of the estimated complex aerosol refractive index range from 1.33 to 1.45 for the real part and 0.001 to 0.008 for the imaginary part. The methodology devised in this study

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

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

    PubMed Central

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

    2016-01-01

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

  18. Biological aerosol background characterization

    NASA Astrophysics Data System (ADS)

    Blatny, Janet; Fountain, Augustus W., III

    2011-05-01

    To provide useful information during military operations, or as part of other security situations, a biological aerosol detector has to respond within seconds or minutes to an attack by virulent biological agents, and with low false alarms. Within this time frame, measuring virulence of a known microorganism is extremely difficult, especially if the microorganism is of unknown antigenic or nucleic acid properties. Measuring "live" characteristics of an organism directly is not generally an option, yet only viable organisms are potentially infectious. Fluorescence based instruments have been designed to optically determine if aerosol particles have viability characteristics. Still, such commercially available biological aerosol detection equipment needs to be improved for their use in military and civil applications. Air has an endogenous population of microorganisms that may interfere with alarm software technologies. To design robust algorithms, a comprehensive knowledge of the airborne biological background content is essential. For this reason, there is a need to study ambient live bacterial populations in as many locations as possible. Doing so will permit collection of data to define diverse biological characteristics that in turn can be used to fine tune alarm algorithms. To avoid false alarms, improving software technologies for biological detectors is a crucial feature requiring considerations of various parameters that can be applied to suppress alarm triggers. This NATO Task Group will aim for developing reference methods for monitoring biological aerosol characteristics to improve alarm algorithms for biological detection. Additionally, they will focus on developing reference standard methodology for monitoring biological aerosol characteristics to reduce false alarm rates.

  19. MISR UAE2 Aerosol Versioning

    Atmospheric Science Data Center

    2013-03-21

    ... the MISR aerosol microphysical properties are "Beta." Uncertainty envelopes for the aerosol optical depths are given in  Kahn et ... particle microphysical property validation is in progress, uncertainty envelopes on particle size distribution, shape, and ...

  20. Atmospheric Chemistry: Nature's plasticized aerosols

    NASA Astrophysics Data System (ADS)

    Ziemann, Paul J.

    2016-01-01

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

  1. Aerosol characterization with lidar methods

    NASA Astrophysics Data System (ADS)

    Sugimoto, Nobuo; Nishizawa, Tomoaki; Shimizu, Atsushi; Matsui, Ichiro

    2014-08-01

    Aerosol component analysis methods for characterizing aerosols were developed for various types of lidars including polarization-sensitive Mie scattering lidars, multi-wavelength Raman scattering lidars, and multi-wavelength highspectral- resolution lidars. From the multi-parameter lidar data, the extinction coefficients for four aerosol components can be derived. The microphysical parameters such as single scattering albedo and effective radius can be also estimated from the derived aerosol component distributions.

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

    SciTech Connect

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

    1997-04-04

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

  3. SAGE II aerosol validation - Selected altitude measurements, including particle micromeasurements

    NASA Technical Reports Server (NTRS)

    Oberbeck, Verne R.; Russell, Philip B.; Pueschel, Rudolf F.; Snetsinger, Kenneth G.; Ferry, Guy V.; Livingston, John M.; Rosen, James N.; Osborn, Mary T.; Kritz, Mark A.

    1989-01-01

    The validity of particulate extinction coefficients derived from limb path solar radiance measurements obtained during the Stratospheric Aerosol and Gas Experiment (SAGE) II is tested. The SAGE II measurements are compared with correlative aerosol measurements taken during January 1985, August 1985, and July 1986 with impactors, laser spectrometers, and filter samplers on a U-2 aircraft, an upward pointing lidar on a P-3 aircraft, and balloon-borne optical particle counters. The data for July 29, 1986 are discussed in detail. The aerosol measurements taken on this day at an altitude of 20.5 km produce particulate extinction values which validate the SAGE II values for similar wavelengths.

  4. The Impact of Aerosols Generated from Biomass Burning, Dust Storms, and Volcanoes Upon the Earth's Radiative Energy Budget

    NASA Technical Reports Server (NTRS)

    Christopher, Sundar A.

    1997-01-01

    A new technique for detecting aerosols from biomass burning and dust is developed. The radiative forcing of aerosols is estimated over four major ecosystems in South America. A new smoke and fire detection scheme is developed for biomass burning aerosols over South America. Surface shortware irradiance calculations are developed in the presence of biomass burning aerosols during the SCAR-B experiment. This new approach utilizes ground based, aircraft, and satellite measurements.

  5. Measurements of Nitric Acid and Aerosol Species Aboard the NASA DC-8 Aircraft During the SASS OZone and Nitrogen Oxide Experiment (SONEX)

    NASA Technical Reports Server (NTRS)

    Talbot, Robert W.; Dibb, Jack E.

    1999-01-01

    The SASS Ozone and Nitrogen Oxides Experiment (SONEX) over the north Atlantic during October/November 1997 offered an excellent opportunity to examine the budget of total reactive nitrogen (NO(y)) in the upper troposphere (8 - 12 km altitude). The median measured NO(y) mixing ratio was 425 parts per trillion by volume (pptv). Two different methods were used to measure HNO3: (1) the mist chamber technique and, (2) chemical ionization mass spectrometry. Two merged data sets using these HNO3 measurements were used to calculate NO(y) by summing the reactive nitrogen species (a combination of measured plus modeled results) and comparing the resultant values to measured NO(y) (gold catalytic reduction method). Both comparisons showed good agreement in the two quantities (slope greater than 0.9 and r(sup 2) greater than 0.9). Thus, the total reactive nitrogen budget in the upper troposphere over the North Atlantic can be explained in a general manner as a simple mixture of NO(x). (NO + NO2), HNO3, and PAN. Median values of NO(x)/NO(y) were approx. = 0.25, HNO3/NO(y) approx. = 0.35 and PAN/NO(y) approx. = 0.17. Particulate NO3 and alkyl nitrates together composed less than 10% of NO(y), while model estimated HNO4 averaged 12%.

  6. Measurements of Nitric Acid and Aerosol Species Aboard the NASA DC-8 Aircraft During the SASS Ozone and Nitrogen Oxide Experiment (SONEX)

    NASA Technical Reports Server (NTRS)

    Talbot, Robert W.; Dibb, Jack E.

    1999-01-01

    The SASS Ozone and Nitrogen Oxides Experiment (SONEX) over the North Atlantic during October/November 1997 offered an excellent opportunity to examine the budget of total reactive nitrogen (NO(sub y)) in the upper troposphere (8 - 12 km altitude). The median measured NO(sub y) mixing ratio was 425 parts per trillion by volume (pptv). Two different methods were used to measure HNO3: (1) the mist chamber technique and, (2) chemical ionization mass spectrometry. Two merged data sets using these HNO3 measurements were used to calculate NO(sub y) by summing the reactive nitrogen species (a combination of measured plus modeled results) and comparing the resultant values to measured NO(sub y) (gold catalytic reduction method). Both comparisons showed good agreement in the two quantities (slope > 0.9 and r(exp 2) > 0.9). Thus, the total reactive nitrogen budget in the upper troposphere over the North Atlantic can be explained in a general manner as a simple mixture of NO(sub x). (NO + NO2), HNO3, and PAN. Median values of NO(sub x)/NO(sub y) were approximately equal to 0.25, HNO3/NO(sub y) were approximately equal to 0.35 and Peroxyacetyl Nitrate (PAN)/NO(sub y) were approximately equal to 0. 17. Particulate NO3 and alkyl nitrates together composed <10 % of NO(sub y), while model estimated HNO4 averaged 12%.

  7. HARLIE 3-D Aerosol Backscatter and Wind Profile Measurements During Recent Field Experiments: Background Noise Reduction with a Fabry-Perot Etalon Filter in the HARLIE System

    NASA Technical Reports Server (NTRS)

    Lee, Sangwoo; Miller, David O.; Schwemmer, Geary; Wilkerson, Thomas D.; Andrus, Ionio; Egbert, Cameron; Anderson, Mark; Starr, David OC. (Technical Monitor)

    2002-01-01

    Background noise reduction of War signals is one of the most important factors in achieving better signal to noise ratio and precise atmospheric data from Mar measurements. Fahey Perot etalons have been used in several lidar systems as narrow band pass filters in the reduction of scattered sunlight. An slalom with spectral bandwidth, (Delta)v=0.23/cm, free spectral range, FSR=6.7/cm, and diameter, d=24mm was installed in a fiber coupled box which included a 500 pm bandwidth interference Filter. The slalom box couples the telescope and detector with 200 pm core fibers and 21 mm focal length collimators. The angular magnification is M=48. The etalon box was inserted into the Holographic Airborne Rotating Lidar Instrument Experiment (HARLIE) system and tested during the HARGLO-2 intercomparison campaign conducted in November 2001 at Wallops Island, Virginia. This paper presents the preliminary test results of the slalom and a complete analysis will be presented at the conference.

  8. Aerosol Quality Monitor (AQUAM)

    NASA Astrophysics Data System (ADS)

    Liang, X.; Ignatov, A.

    2011-12-01

    The Advanced Clear-Sky Processor for Oceans (ACSPO) developed at NESDIS generates three products from AVHRR, operationally: clear sky radiances in all bands, and sea surface temperature (SST) derived from clear-sky brightness temperatures (BT) in Ch3B (centered at 3.7 μm), Ch4 (11 μm) and Ch5 (12 μm), and aerosol optical depths (AOD) derived from clear-sky reflectances in Ch1 (0.63), Ch2 (0.83) and Ch3A (1.61 μm). An integral part of ACSPO is the fast Community Radiative Transfer Model (CRTM), which calculates first-guess clear-sky BTs using global NCEP forecast atmospheric and Reynolds SST fields. Simulated BTs are employed in ACSPO for improved cloud screening, physical (RTM-based) SST inversions, and to monitor and validate satellite BTs. The model minus observation biases are monitored online in near-real time using the Monitoring IR Clear-sky radiances over Oceans for SST (MICROS; http://www.star.nesdis.noaa.gov/sod/sst/micros/). A persistent positive M-O bias is observed in MICROS, partly attributed to missing aerosol in CRTM input, causing "M" to be warmer than "O". It is thus necessary to include aerosols in CRTM and quantify their effects on AVHRR BTs and SSTs. However, sensitivity of thermal bands to aerosol is only minimal, and use of solar reflectance bands is preferable to evaluate the accuracy of CRTM modeling, with global aerosol fields as input (from e.g. Goddard Chemistry Aerosol Radiation and Transport, GOCART, or Navy Aerosol Analysis and Prediction System, NAAPS). Once available, the corresponding M-O biases in solar reflectance bands will be added to MICROS. Also, adding CRTM simulated reflectances in ACSPO would greatly improve cloud detection, help validate CRTM in the solar reflectance bands, and assist aerosol retrievals. Running CRTM with global aerosol as input is very challenging, computationally. While CRTM is being optimized to handle such global scattering computations, a near-real time web-based Aerosol Quality Monitor (AQUAM

  9. Cantera Aerosol Dynamics Simulator

    SciTech Connect

    Moffat, Harry

    2004-09-01

    The Cantera Aerosol Dynamics Simulator (CADS) package is a general library for aerosol modeling to address aerosol general dynamics, including formation from gas phase reactions, surface chemistry (growth and oxidation), bulk particle chemistry, transport by Brownian diffusion, thermophoresis, and diffusiophoresis with linkage to DSMC studies, and thermal radiative transport. The library is based upon Cantera, a C++ Cal Tech code that handles gas phase species transport, reaction, and thermodynamics. The method uses a discontinuous galerkin formulation for the condensation and coagulation operator that conserves particles, elements, and enthalpy up to round-off error. Both O-D and 1-D time dependent applications have been developed with the library. Multiple species in the solid phase are handled as well. The O-D application, called Tdcads (Time Dependent CADS) is distributed with the library. Tdcads can address both constant volume and constant pressure adiabatic homogeneous problems. An extensive set of sample problems for Tdcads is also provided.

  10. Aerosol optical properties over the midcontinental United States

    SciTech Connect

    Halthore, R.N. ); Markham, B.L.; Ferrare, R.A. ); Aro, T.O. )

    1992-11-30

    This work is part of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), an international land-surface-atmosphere experiment aimed at improving the way climate models represent energy, water, heat, and carbon exchanges, and improving the utilization of satellite based remote sensing to monitor such parameters. Here the authors report on measurements of aerosol optical depth over the FIFE site, making use of a calibrated Sun photometer. Aerosols are relevant for the impact they have on remotely sensed measurements of radiation effects on the earth. They also play a major role in cloud formation, and can impact the atmospheric concentration of minor species gases. Here the authors look at the meteorological effects on aerosols in the troposphere. Wavelength dependence gives information on the size distributions within the aerosols. During 1987 they observe mixing of gulf air with continental air over the site. They report on correlation with surface values of pressure, temperature, specific, and relative humidity.

  11. Aerosol Interactions with Extensive Stratus Cloud During VOCALS

    NASA Astrophysics Data System (ADS)

    Clarke, A. D.; McNaughton, C. S.; Freitag, S.; Howell, S.; Kapustin, V.; Snider, J.; Campos, T. L.; Leon, D.; Shank, L.; Wood, R.

    2009-12-01

    The 2008 VOCALS experiment over the Pacific and off the north coast of Chile provided numerous opportunities to examine aerosol-stratus interactions over 1000km flight legs and processes associated with their breakup into pockets of open cells (POC’s). Our HiGEAR (Hawaii Group for Environmental Aerosol Research) measurements on the NCAR C-130 aircraft included the aerosol size-distribution, size-resolved volatile and non-volatile components, ionic and organic chemistry (AMS), black carbon (BC, as measured by Single Particle Soot Photometer - SP2) and associated optical properties. We are exploring these observations in conjunction with meteorological data, trace gas data (eg. O3, CO) and cloud condensation nuclei (CCN) to resolve features related to the source, removal and evolution of aerosol active as CCN. Stratus clouds decks along the coast were heavily impacted by anthropogenic combustion sources along the coast. Offshore in the marine boundary layer (MBL) below cloud these influences diminished and transitioned to clean central Pacific aerosol west of about 75W. Periods with smallest aerosol sizes tended to show subsidence around the South Pacific high pressure system while larger sizes had spent more time in the MBL. However, at various altitudes in the free troposphere (FT) above cloud, relatively low concentrations of biomass burning (BB) aerosol occurred in patches and “rivers” of flow. These BB aerosol were often near cloud top or within a day of subsiding to cloud top for estimated rates of about 0.4 cm/s. The BB aerosol was generally associated with elevated CO, organic, non-volatile aerosol, and BC. POC’s were lowest in CO compared to both adjacent cloudy air and FT air, indicating less prior influence from combustion aerosol than cloudy regions. POC regions manifested dramatic aerosol reduction through precipitation and drizzle resulting in low concentrations with diameters often less than about 40nm. Offshore, drizzling cloudy regions

  12. Organic Aerosols from SÃO Paulo and its Relationship with Aerosol Absorption and Scattering Properties

    NASA Astrophysics Data System (ADS)

    Artaxo, P.; Brito, J. F.; Rizzo, L. V.

    2012-12-01

    The megacity of São Paulo with its 19 million people and 7 million cars is a challenge from the point of view of air pollution. High levels of organic aerosols, PM10, black carbon and ozone and the peculiar situation of the large scale use of ethanol fuel makes it a special case. Little is known about the impact of ethanol on air quality and human health and the increase of ethanol as vehicle fuel is rising worldwide An experiment was designed to physico-chemical properties of aerosols in São Paulo, as well as their optical properties. Aerosol size distribution in the size range of 1nm to 10 micrometers is being measured with a Helsinki University SMPS (Scanning Mobility Particle Sizer), an NAIS (Neutral ion Spectrometer) and a GRIMM OPC (Optical Particle Counter). Optical properties are being measured with a TSI Nephelometer and a Thermo MAAP (Multi Angle Absorption Photometer). A CIMEL sunphotometer from the AERONET network measure the aerosol optical depth. Furthermore, a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS) and an Aerosol Chemical Speciation Monitor (ACSM) are used to real-time VOC analysis and aerosol composition, respectively. The ACSM was operated for 3 months continuosly during teh wintertime of 2012. The measured total particle concentration typically varies between 10,000 and 30,000 cm-3 being the lowest late in the night and highest around noon and frequently exceeding 50,000 cm-3. Clear diurnal patterns in aerosol optical properties were observed. Scattering and absorption coefficients typically range between 20 and 100 Mm-1 at 450 nm, and between 10 to 40 Mm-1 at 637 nm, respectively, both of them peaking at 7:00 local time, the morning rush hour. The corresponding single scattering albedo varies between 0.50 and 0.85, indicating a significant contribution of primary absorbing particles to the aerosol population. During the first month a total of seven new particle formation events were observed with growth rates ranging from 9 to 25

  13. Detection of chemical agent aerosols

    NASA Astrophysics Data System (ADS)

    Fox, Jay A.; Ahl, Jeffrey L.; D'Amico, Francis M.; Vanderbeek, Richard G.; Moon, Raphael; Swim, Cynthia R.

    1999-05-01

    One of the major threats presented by a chemical agent attack is that of a munition exploding overhead and 'raining' aerosols which can contaminate surfaces when they impact. Since contact with these surfaces can be fatal, it is imperative to know when such an attack has taken place and the likely threat density and location. We present the results of an experiment designed to show the utility of a CO2 lidar in detecting such an attack. Testing occurred at Dugway Proving Grounds, Utah and involved the simulation of an explosive airburst chemical attack. Explosions occurred at a height of 30 m and liquid droplets from two chemicals, PEG-200 (polyethylene glycol 200) and TEP (triethylphosphate), were expelled and fell to the ground. The munition was the U.S. Army M9 Simulator, Projectile, Airburst, Liquid (SPAL) system that is designed for chemical warfare training exercises. The instrument that was used to detect the presence of the aerosols was the Laser Standoff Chemical Detector (LSCD) which is a light detection and ranging (LIDAR) system that utilizes a rapidly tunable, pulsed CO2 laser. The LIDAR scanned a horizontal path approximately 5 - 8 m above the ground in order to measure the concentration of liquid deposition. The LIDAR data were later correlated with card data to determine how well the system could predict the location and quantity of liquid deposition on the ground.

  14. Physical characterization of incense aerosols.

    PubMed

    Mannix, R C; Nguyen, K P; Tan, E W; Ho, E E; Phalen, R F

    1996-12-20

    Experiments were performed to study the physical characteristics of smoke aerosols generated by burning three types of stick incense in a 4 m3 clean room. Sidestream cigarette smoke was also examined under the same conditions to provide a comparison. Among the parameters measured were (a) masses of aerosol, carbon monoxide and nitrogen oxides generated by burning the incense or cigarettes, (b) rates of decay of the particles from the air, and (c) estimates of count median particle size during a 7 h period post-burning. There was variability among the types of incense studied with respect to many of the parameters. Also, as a general trend, the greater the initial particulate mass concentration, the more rapid the rate of decay of the smoke. In relation to the quantity of particulate generated, cigarette smoke was found to produce proportionally larger quantities of carbon monoxide and nitrogen oxides than did incense. Due to the fact that burning incense was found to generate large quantities of particulate (an average of greater than 45 mg/g burned, as opposed to about 10 mg/g burned for the cigarettes), it is likely, in cases in which incense is habitually burned in indoor settings, that such a practice would produce substantial airborne particulate concentrations.

  15. simplified aerosol representations in global modeling

    NASA Astrophysics Data System (ADS)

    Kinne, Stefan; Peters, Karsten; Stevens, Bjorn; Rast, Sebastian; Schutgens, Nick; Stier, Philip

    2015-04-01

    The detailed treatment of aerosol in global modeling is complex and time-consuming. Thus simplified approaches are investigated, which prescribe 4D (space and time) distributions of aerosol optical properties and of aerosol microphysical properties. Aerosol optical properties are required to assess aerosol direct radiative effects and aerosol microphysical properties (in terms of their ability as aerosol nuclei to modify cloud droplet concentrations) are needed to address the indirect aerosol impact on cloud properties. Following the simplifying concept of the monthly gridded (1x1 lat/lon) aerosol climatology (MAC), new approaches are presented and evaluated against more detailed methods, including comparisons to detailed simulations with complex aerosol component modules.

  16. Highly stable aerosol generator

    SciTech Connect

    DeFord, Henry S.; Clark, Mark L.

    1981-01-01

    An improved compressed air nebulizer has been developed such that a uniform aerosol particle size and concentration may be produced over long time periods. This result is achieved by applying a vacuum pressure to the makeup assembly and by use of a vent tube between the atmosphere and the makeup solution. By applying appropriate vacuum pressures to the makeup solution container and by proper positioning of the vent tube, a constant level of aspirating solution may be maintained within the aspirating assembly with aspirating solution continuously replaced from the makeup solution supply. This device may also be adapted to have a plurality of aerosol generators and only one central makeup assembly.

  17. Highly stable aerosol generator

    DOEpatents

    DeFord, H.S.; Clark, M.L.

    1981-11-03

    An improved compressed air nebulizer has been developed such that a uniform aerosol particle size and concentration may be produced over long time periods. This result is achieved by applying a vacuum pressure to the makeup assembly and by use of a vent tube between the atmosphere and the makeup solution. By applying appropriate vacuum pressures to the makeup solution container and by proper positioning of the vent tube, a constant level of aspirating solution may be maintained within the aspirating assembly with aspirating solution continuously replaced from the makeup solution supply. This device may also be adapted to have a plurality of aerosol generators and only one central makeup assembly. 2 figs.

  18. Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

    aerosol Angstrom absorption exponents by linear regression over the entire UV-visible spectral range. These results are compared to results obtained from the absorbance measurements obtained in the field. The differences in calculated Angstrom absorption exponents between the field and laboratory measurements are attributed partly to the differences in time resolution of the sample collection resulting in heavier particle pileup on the filter surface of the 12-hour samples. Some differences in calculated results can also be attributed to the presence of narrow band absorbers below 400 nm that do not fall in the wavelengths covered by the 7 wavelengths of the aethalometer. 1. Marley, N.A., J.S. Gaffney, J.C. Baird, C.A. Blazer, P.J. Drayton, and J.E. Frederick, "The determination of scattering and absorption coefficients of size-fractionated aerosols for radiative transfer calculations." Aerosol Sci. Technol., 34, 535-549, (2001). This work was conducted as part of the Department of Energy's Atmospheric Science Program as part of the Megacity Aerosol Experiment - Mexico City during MILAGRO. This research was supported by the Office of Science (BER), U.S. Department of Energy Grant No. DE-FG02-07ER64329. We also wish to thank Mexican Scientists and students for their assistance from the Instituto Mexicano de Petroleo (IMP) and CENICA.

  19. Interpretation of FRESCO cloud retrievals in case of absorbing aerosol events

    NASA Astrophysics Data System (ADS)

    Wang, P.; Tuinder, O. N. E.; Tilstra, L. G.; Stammes, P.

    2011-12-01

    Cloud and aerosol information is needed in trace gas retrievals from satellite measurements. The Fast REtrieval Scheme for Clouds from the Oxygen A band (FRESCO) cloud algorithm employs reflectance spectra of the O2 A band around 760 nm to derive cloud pressure and effective cloud fraction. In general, clouds contribute more to the O2 A band reflectance than aerosols. Therefore, the FRESCO algorithm does not correct for aerosol effects in the retrievals and attributes the retrieved cloud information entirely to the presence of clouds, and not to aerosols. For events with high aerosol loading, aerosols may have a dominant effect, especially for almost cloud-free scenes. We have analysed FRESCO cloud data and Absorbing Aerosol Index (AAI) data from the Global Ozone Monitoring Experiment (GOME-2) instrument on the Metop-A satellite for events with typical absorbing aerosol types, such as volcanic ash, desert dust and smoke. We find that the FRESCO effective cloud fractions are correlated with the AAI data for these absorbing aerosol events and that the FRESCO cloud pressures contain information on aerosol layer pressure. For cloud-free scenes, the derived FRESCO cloud pressures are close to those of the aerosol layer for optically thick aerosols. For cloudy scenes, if the strongly absorbing aerosols are located above the clouds, then the retrieved FRESCO cloud pressures may represent the height of the aerosol layer rather than the height of the clouds. Combining FRESCO cloud data and AAI, an estimate for the aerosol layer pressure can be given, which can be beneficial for aviation safety and operations in case of e.g. volcanic ash plumes.

  20. Global atmospheric sulfur budget under volcanically quiescent conditions: Aerosol-chemistry-climate model predictions and validation

    NASA Astrophysics Data System (ADS)

    Sheng, Jian-Xiong; Weisenstein, Debra K.; Luo, Bei-Ping; Rozanov, Eugene; Stenke, Andrea; Anet, Julien; Bingemer, Heinz; Peter, Thomas

    2015-01-01

    The global atmospheric sulfur budget and its emission dependence have been investigated using the coupled aerosol-chemistry-climate model SOCOL-AER. The aerosol module comprises gaseous and aqueous sulfur chemistry and comprehensive microphysics. The particle distribution is resolved by 40 size bins spanning radii from 0.39 nm to 3.2 μm, including size-dependent particle composition. Aerosol radiative properties required by the climate model are calculated online from the aerosol module. The model successfully reproduces main features of stratospheric aerosols under nonvolcanic conditions, including aerosol extinctions compared to Stratospheric Aerosol and Gas Experiment II (SAGE II) and Halogen Occultation Experiment, and size distributions compared to in situ measurements. The calculated stratospheric aerosol burden is 109 Gg of sulfur, matching the SAGE II-based estimate (112 Gg). In terms of fluxes through the tropopause, the stratospheric aerosol layer is due to about 43% primary tropospheric aerosol, 28% SO2, 23% carbonyl sulfide (OCS), 4% H2S, and 2% dimethyl sulfide (DMS). Turning off emissions of the short-lived species SO2, H2S, and DMS shows that OCS alone still establishes about 56% of the original stratospheric aerosol burden. Further sensitivity simulations reveal that anticipated increases in anthropogenic SO2 emissions in China and India have a larger influence on stratospheric aerosols than the same increase in Western Europe or the U.S., due to deep convection in the western Pacific region. However, even a doubling of Chinese and Indian emissions is predicted to increase the stratospheric background aerosol burden only by 9%. In contrast, small to moderate volcanic eruptions, such as that of Nabro in 2011, may easily double the stratospheric aerosol loading.

  1. Clear Sky Column Closure Studies of Urban-Marine and Mineral-Dust Aerosols Using Aircraft, Ship, Satellite and Ground-Based Measurements in ACE-2

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Russell, Philip B.; Livingston, John M.; Gasso, Santiago; Hegg, Dean A.; Collins, Donald R.; Flagan, Richard C.; Seinfeld, John H.; Oestroem, Elisabeth; Noone, Kevin J.; Durkee, Philip A.; Jonsson, Haflidi H.; Welton, Ellsworth J.; Voss, Kenneth J.; Gordon, Howard R.; Formenti, Paola; Andreae, Meinrat O.; Kapustin, Vladimir N.; Bates, Timothy S.; Quinn, Patricia K.

    2000-01-01

    As part of the second Aerosol Characterization Experiment (ACE-2), European urban-marine and African mineral-dust aerosols were measured aboard the Pelican aircraft, the Research Vessel Vodyanitskiy from the ground and from satellites.

  2. Geometrical Optics of Dense Aerosols

    SciTech Connect

    Hay, Michael J.; Valeo, Ernest J.; Fisch, Nathaniel J.

    2013-04-24

    Assembling a free-standing, sharp-edged slab of homogeneous material that is much denser than gas, but much more rare ed than a solid, is an outstanding technological challenge. The solution may lie in focusing a dense aerosol to assume this geometry. However, whereas the geometrical optics of dilute aerosols is a well-developed fi eld, the dense aerosol limit is mostly unexplored. Yet controlling the geometrical optics of dense aerosols is necessary in preparing such a material slab. Focusing dense aerosols is shown here to be possible, but the nite particle density reduces the eff ective Stokes number of the flow, a critical result for controlled focusing. __________________________________________________

  3. The on-line analysis of aerosol-delivered pharmaceuticals via single particle aerosol mass spectrometry.

    PubMed

    Morrical, Bradley D; Balaxi, Maria; Fergenson, David

    2015-07-15

    The use of single particle aerosol mass spectrometry (SPAMS) was evaluated for the analysis of inhaled pharmaceuticals to determine the mass distribution of the individual active pharmaceutical ingredients (API) in both single ingredient and combination drug products. SPAMS is an analytical technique where the individual aerodynamic diameters and chemical compositions of many aerosol particles are determined in real-time. The analysis was performed using a Livermore Instruments SPAMS 3.0, which allowed the efficient analysis of aerosol particles with broad size distributions and can acquire data even under a very large particle load. Data similar to what would normally require roughly three days of experimentation and analysis was collected in a five minute period and analyzed automatically. The results were computed to be comparable to those returned by a typical Next Generation Impactor (NGI) particle size distribution experiment.

  4. Simulating Aerosol-cloud-radiation Feedbacks over East Asia Using Wrf-chem

    NASA Astrophysics Data System (ADS)

    Wang, J.; Allen, D. J.; Pickering, K. E.; Li, Z.; Dickerson, R. R.

    2011-12-01

    Aerosols play an important role in climate change through their impact on the radiative balance of the atmosphere. Recently much effort has been put into studying the radiative forcing of aerosols in East Asia. In this study, we apply the regional chemistry and transport model, WRF-Chem, to study aerosol radiative forcing over eastern Asia. Version 3.3 of the model is used with the CBMZ chemical mechanism and the MOSAIC aerosol treatment. The time period of interest is Feb 21, 2005 to April 12, 2005, since there were extensive measurements of radiation, trace gases, and aerosol properties available from EAST-AIRE (East Asian Study of Tropospheric Aerosols: An International Regional Experiment ) campaign during that period. We conduct model simulations with and without aerosol forcing and compare the results to measurements. We investigate the aerosol radiative forcing as well as aerosol direct and indirect effects by analyzing the differences between short wave flux, temperature, and cloud fraction from these two runs. We evaluate our model simulated incoming short wave radiation at the surface with in situ measurements from EAST-AIRE site Xianghe (70 km southeast of Beijing, China). We find that shortwave radiation decreases when aerosols are added lessening the high-bias between model-calculated and observed short wave radiation. We further compare the model simulated cloud fraction from two runs with MODIS Level 2 retrievals, demonstrating aerosol indirect effects in cloud formations.

  5. Mesospheric aerosol sampling spectrometer

    NASA Astrophysics Data System (ADS)

    Knappmiller, Scott; Robertson, Scott; Sternovsky, Zoltan; Horanyi, Mihaly; Kohnert, Rick

    . The Mesospheric Aerosol Sampling Spectrometer (MASS) instrument has been launched on two sounding rockets in August, 2007 from Andoya, Norway to detect charged sub-visible aerosol particles in the polar mesosphere. The MASS instrument is designed to collect charged aerosols, cluster ions, and electrons on four pairs of graphite electrodes, three of which are biased with increasing voltage. The design of the MASS instrument was complicated by the short mean free path in the mesosphere. The opening to MASS was deliberately built to increase the mean free path and to reduce the shock wave within the instrument. The design procedure began with aerodynamics simulations of the flow through the instrument using Direct Simulation Monte Carlo (DSMC) in 3-D. The electric fields within the instrument were calculated using a Laplace solver in 3-D. With the aerodynamic and electric field simulations completed, an algorithm was created to find the trajectories of charged aerosols including collisions within MASS. Using this algorithm the collection efficiencies for each electrode was calculated as a function of the charge to mass ratio of the incoming particle. The simulation results have been confirmed experimentally using an Argon RF ion beam. The data from the August launches have been analyzed and the initial results show the MASS instrument operated as expected. Additional studies are underway to determine if there were effects from payload charging or spurious charge generation within the instrument. This project is supported by NASA.

  6. Marine aerosol formation from biogenic iodine emissions.

    PubMed

    O'Dowd, Colin D; Jimenez, Jose L; Bahreini, Roya; Flagan, Richard C; Seinfeld, John H; Hämeri, Kaarle; Pirjola, Liisa; Kulmala, Markku; Jennings, S Gerard; Hoffmann, Thorsten

    2002-06-01

    The formation of marine aerosols and cloud condensation nuclei--from which marine clouds originate--depends ultimately on the availability of new, nanometre-scale particles in the marine boundary layer. Because marine aerosols and clouds scatter incoming radiation and contribute a cooling effect to the Earth's radiation budget, new particle production is important in climate regulation. It has been suggested that sulphuric acid derived from the oxidation of dimethyl sulphide is responsible for the production of marine aerosols and cloud condensation nuclei. It was accordingly proposed that algae producing dimethyl sulphide play a role in climate regulation, but this has been difficult to prove and, consequently, the processes controlling marine particle formation remains largely undetermined. Here, using smog chamber experiments under coastal atmospheric conditions, we demonstrate that new particles can form from condensable iodine-containing vapours, which are the photolysis products of biogenic iodocarbons emitted from marine algae. Moreover, we illustrate, using aerosol formation models, that concentrations of condensable iodine-containing vapours over the open ocean are sufficient to influence marine particle formation. We suggest therefore that marine iodocarbon emissions have a potentially significant effect on global radiative forcing.

  7. Marine aerosol formation from biogenic iodine emissions.

    PubMed

    O'Dowd, Colin D; Jimenez, Jose L; Bahreini, Roya; Flagan, Richard C; Seinfeld, John H; Hämeri, Kaarle; Pirjola, Liisa; Kulmala, Markku; Jennings, S Gerard; Hoffmann, Thorsten

    2002-06-01

    The formation of marine aerosols and cloud condensation nuclei--from which marine clouds originate--depends ultimately on the availability of new, nanometre-scale particles in the marine boundary layer. Because marine aerosols and clouds scatter incoming radiation and contribute a cooling effect to the Earth's radiation budget, new particle production is important in climate regulation. It has been suggested that sulphuric acid derived from the oxidation of dimethyl sulphide is responsible for the production of marine aerosols and cloud condensation nuclei. It was accordingly proposed that algae producing dimethyl sulphide play a role in climate regulation, but this has been difficult to prove and, consequently, the processes controlling marine particle formation remains largely undetermined. Here, using smog chamber experiments under coastal atmospheric conditions, we demonstrate that new particles can form from condensable iodine-containing vapours, which are the photolysis products of biogenic iodocarbons emitted from marine algae. Moreover, we illustrate, using aerosol formation models, that concentrations of condensable iodine-containing vapours over the open ocean are sufficient to influence marine particle formation. We suggest therefore that marine iodocarbon emissions have a potentially significant effect on global radiative forcing. PMID:12050661

  8. Field and Laboratory Studies of Atmospheric Organic Aerosol

    NASA Astrophysics Data System (ADS)

    Coggon, Matthew Mitchell

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

  9. Toward Investigating Optically Trapped Organic Aerosols with CARS Microspectroscopy

    NASA Astrophysics Data System (ADS)

    Voss, L. F.

    2009-12-01

    The Intergovernmental Panel on Climate Change notes the huge uncertainty in the effect that atmospheric aerosols play in determining overall global temperature, specifically in their ability to nucleate clouds. To better understand aerosol chemistry, the novel coupling of gradient force optical trapping with broad bandwidth coherent anti-Stokes Raman scattering (CARS) spectroscopy is being developed to study single particles suspended in air. Building on successful designs employed separately for the techniques, this hybrid technology will be used to explain how the oxidation of organic compounds changes the chemical and physical properties of aerosols. By trapping the particles, an individual aerosol can be studied for up to several days. Using a broad bandwidth pulse for one of the incident beams will result in a Raman vibrational spectrum from every laser pulse. Combined with signal enhancement due to resonance and coherence of nonlinear CARS spectroscopy, this technique will allow for acquisition of data on the millisecond time scale, facilitating the study of dynamic processes. This will provide insights on how aerosols react with and absorb species from the gas phase. These experiments will increase understanding of aerosol oxidation and growth mechanisms and the effects that aerosols have on our atmosphere and climate. Progress in efforts developing this novel technique to study model systems is presented.

  10. Space measurements of tropospheric aerosols

    NASA Technical Reports Server (NTRS)

    Griggs, M.

    1981-01-01

    A global-scale ground-truth experiment was conducted in the summer of 1980 with the AVHRR sensor on NOAA-6 to investigate the relationship between the upwelling visible radiance and the aerosol optical thickness over oceans at different sites around the globe. The possibility of using inland bodies of water such as rivers, lakes and reservoirs has been recently investigated using the Landsat MSS7 (approximately 0.9 micron) channel. This upwelling near-infrared radiance is less influenced than the visible radiance by the suspended matter generally found in the inland bodies of water, and by the adjacency effect of the surrounding higher albedo land. It is found that the water turbidity has more influence than the adjacency effect and reduces the effectiveness of the technique for inland observations.

  11. Measuring Aerosol Optical Properties with the Ozone Monitoring Instrument (OMI)

    NASA Technical Reports Server (NTRS)

    Veefkind, J. P.; Torres, O.; Syniuk, A.; Decae, R.; deLeeuw, G.

    2003-01-01

    The Ozone Monitoring Instrument (OMI) is the Dutch-Finnish contribution to the NASA EOS-Aura mission scheduled for launch in January 2004. OM1 is an imaging spectrometer that will measure the back-scattered Solar radiance between 270 an 500 nm. With its relatively high spatial resolution (13x24 sq km at nadir) and daily global coverage. OM1 will make a major contribution to our understanding of atmospheric chemistry and to climate research. OM1 will provide data continuity with the TOMS instruments. One of the pleasant surprises of the TOMS data record was its information on aerosol properties. First, only the absorbing aerosol index, which is sensitive to elevated lay- ers of aerosols such as desert dust and smoke aerosols, was derived. Recently these methods were further improved to yield aerosol optical thickness and single scattering albedo over land and ocean for 19 years of TOMS data (1979-1992,1997-2002), making it one of the longest and most valuable time series for aerosols presently available. Such long time series are essential to quantify the effect of aerosols on the Earth& climate. The OM1 instrument is better suited to measure aerosols than the TOMS instruments because of the smaller footprint, and better spectral coverage. The better capabilities of OMI will enable us to provide an improved aerosol product, but the knowledge will also be used for further analysis of the aerosol record from TOMS. The OM1 aerosol product that is currently being developed for OM1 combines the TOMS experience and the multi-spectral techniques that are used in the visible and near infrared. The challenge for this new product is to provide aerosol optical thickness and single scattering albedo from the near ultraviolet to the visible (330-500 nm) over land and ocean. In this presentation the methods for deriving the OM1 aerosol product will be presented. Part of these methods developed for OM1 can already be applied to TOMS data and results of such analysis will be shown.

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

    SciTech Connect

    Richard Ferrare, Connor Flynn, David Turner

    2009-05-05

    . Analysis of the aerosol and water vapor data collected by the Raman lidar during the 2003 Aerosol IOP indicated that the sensitivity of the lidar was significantly lower than when the lidar was initially deployed. A detailed analysis after the IOP of the long-term dataset demonstrated that the lidar began degrading in early 2002, and that it lost approximately a factor of 4 in sensitivity between 2002 and 2004. We participated in the development of the remediation plan for the system to restore its initial performance. We conducted this refurbishment and upgrade from May- September 2004. This remediation lead to an increase in the signal-to-noise ratio of 10 and 30 for the Raman lidar's water vapor mixing ratio and aerosol backscatter coefficient data, respectively as compared to the signal strengths when the system was first deployed. The DOE ARM Aerosol Lidar Validation Experiment (ALIVE), which was conducted during September 2005, evaluated the impact of these modifications and upgrades on the SGP Raman lidar measurements of aerosol extinction and optical thickness. The CARL modifications significantly improved the accuracy and temporal resolution of the aerosol measurements. Aerosol extinction profiles measured by the Raman lidar were also used to evaluate aerosol extinction profiles and aerosol optical thickness (AOT) simulated by aerosol models as part of the Aerosol module inter-Comparison in global models (AEROCOM) (http://nansen.ipsl.jussieu.fr/AEROCOM/aerocomhome.html) project. There was a wide range in how the models represent the aerosol extinction profiles over the ARM SGP site, even though the average annual AOT represented by the various models and measured by CARL and the Sun photometer were in general agreement, at least within the standard deviations of the averages. There were considerable differences in the average vertical distributions among the models, even among models that had similar average aerosol optical thickness. Deviations between mean

  13. Anomalies in the South American Monsoon Induced by Aerosols

    NASA Technical Reports Server (NTRS)

    Lau, K. M. William; Kyu-Mong, Kim

    2007-01-01

    We have investigated the direct effects of aerosols on the water cycle of the South American monsoon using the NASA finite-volume general circulation model (fvGCM). Global aerosol forcings are computed from radiative transfer functions derived from global distributions of five species of aerosols, i.e., dust, black carbon, organic carbon, sulphate and sea salt from the Goddard Chemistry Aerosol Radiation Transport (GOCART) model. Comparing fvGCM experiments without aerosol forcing, and with different combinations of aerosol forcing, we evaluate the impacts of aerosol direct heating on the onset, maintenance and evolution of the South American summer monsoon. We find that during the pre-monsoon season (September-October-November) Saharan dust contribute to heating of the atmosphere over the central and eastern equatorial Atlantic/Africa region through the elevated heat pump mechanism. The heating generates an anomalous Walker circulation with sinking motion, and low level northeasterlies over the Caribbean and northwestern South America. The low level flow is blocked by the Andes, and turn south and southeastward, increasing the low level jet (LLJ) along the eastern slope of the Andes. The increased LLJ transports more moisture from the Atlantic and the Amazon, enhancing the moisture convergence over subtropical land regions of South America. The moisture convergence was further accelerated by atmospheric heating by biomass burning over the Amazon. The net results of the dust and biomass heating are: a) an advance of the monsoon rainy season, b) an enhanced LLJ and c) a shifting the South America monsoon land precipitation equatorward, with increased rain over southern Brazil and reduced rain over the La Plata basin. ramifications of this elevated heating heat pump mechanism in aerosol monsoon water cycle on climate variability and change will be discussed. The ramifications of this "elevated heating heat pump" mechanism in aerosol monsoom water cycle on climate

  14. Generation and delivery of coal liquid aerosols for inhalation studies

    SciTech Connect

    Springer, D.L.; Clark, M.L.; Willard, D.H.; Mahlum, D.D.

    1982-07-01

    To aid in the toxicologic evaluation of solvent refined coal (SRC) materials, we developed an aerosol generation system for whole-body inhalation exposure of experimental animals to coal liquids. The main components of the exposure system were an aerosol generator, a manifold for delivery of the aerosol, three exposure chambers and an exhaust system. High-boiling coal liquids from the SRC-l and the SRC-ll processes were as test materials. Aerosol concentrations were measured by drawing aerosol samples from the chambers through a Metricel filter and eluting the coal liquid into chloroform.Since these coal liquids have an ultraviolet absorption peak at 254 mm, the absorbance was determined at this wavelength. As part of the experiment, we evaluated the Solo-Sphere, Rec and Collison neubulizer as aerosol generators for the coal liquids. Both the Solo-Sphere and Retec provided adequate concentrations of respirable particles; however, aerosol concentrations within the exposure chamber provided adequate concentrations of respirable particles; however, aerosol concentrations within the exposure chamber were more consistent with the Solo-Sphere. Low mass output and plugging were encountered with the Collison. Use of the Solo-Sphere generator and manifold delivery system resulted in consistent and uniform aerosol concentrations and particle sizes in the exposure chamber over a 15-day test period. Analysis of the chamber atmosphere when SRC-l process solvent was used indicated the presence of vapors as well as particles. The ultraviolet absorption spectrum suggested that two-ring polynuclear aromatic compounds were the major constituents of the vapor phase.

  15. Merging the OSIRIS and SAGE II stratospheric aerosol records

    NASA Astrophysics Data System (ADS)

    Rieger, L. A.; Bourassa, A. E.; Degenstein, D. A.

    2015-09-01

    The Optical Spectrograph and InfraRed Imaging System (OSIRIS) instrument on the Odin satellite, launched in 2001 and currently operational, measures limb-scattered sunlight from which profiles of stratospheric aerosol extinction are retrieved. The Stratospheric Aerosol and Gas Experiment (SAGE) II was launched in 1984 and provided measurements of stratospheric aerosol extinction until mid-2005. This provides approximately 4 years of mission overlap which has allowed us to consistently extend the SAGE II version 7.00 record to the present using OSIRIS aerosol extinction retrievals. In this work we first compare coincident aerosol extinction observations during the overlap period by interpolating the SAGE II 525nm and 1020nm channels to the OSIRIS extinction wavelength of 750nm. In the tropics to midlatitudes mean differences are typically less than 10%, although larger biases are seen at higher latitudes and at altitudes outside the main aerosol layer. OSIRIS aerosol extinction retrievals at 750nm are used to create a monthly time series zonally averaged in 5°bins and qualitatively compared to SAGE II 525nm observations averaged in the same way. The OSIRIS time series is then translated to 525nm with an Ângström exponent relation and bias corrected. For most locations, this provides agreement during the overlap time period to better than 15%. Uncertainty in the resulting OSIRIS time series is estimated through a series of simulation studies over the range of aerosol particle size distributions observed by in situ balloon instruments and is found to be approximately 20% for background and moderately volcanic aerosol loading conditions for the majority of OSIRIS measurement conditions.

  16. A large source of low-volatility secondary organic aerosol.

    PubMed

    Ehn, Mikael; Thornton, Joel A; Kleist, Einhard; Sipilä, Mikko; Junninen, Heikki; Pullinen, Iida; Springer, Monika; Rubach, Florian; Tillmann, Ralf; Lee, Ben; Lopez-Hilfiker, Felipe; Andres, Stefanie; Acir, Ismail-Hakki; Rissanen, Matti; Jokinen, Tuija; Schobesberger, Siegfried; Kangasluoma, Juha; Kontkanen, Jenni; Nieminen, Tuomo; Kurtén, Theo; Nielsen, Lasse B; Jørgensen, Solvejg; Kjaergaard, Henrik G; Canagaratna, Manjula; Maso, Miikka Dal; Berndt, Torsten; Petäjä, Tuukka; Wahner, Andreas; Kerminen, Veli-Matti; Kulmala, Markku; Worsnop, Douglas R; Wildt, Jürgen; Mentel, Thomas F

    2014-02-27

    Forests emit large quantities of volatile organic compounds (VOCs) to the atmosphere. Their condensable oxidation products can form secondary organic aerosol, a significant and ubiquitous component of atmospheric aerosol, which is known to affect the Earth's radiation balance by scattering solar radiation and by acting as cloud condensation nuclei. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non-volatile organic vapours, but the sources and compositions of such vapours remain unknown. Here we investigate the oxidation of VOCs, in particular the terpene α-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours. These vapours form at significant mass yield in the gas phase and condense irreversibly onto aerosol surfaces to produce secondary organic aerosol, helping to explain the discrepancy between the observed atmospheric burden of secondary organic aerosol and that reported by many model studies. We further demonstrate how these low-volatility vapours can enhance, or even dominate, the formation and growth of aerosol particles over forested regions, providing a missing link between biogenic VOCs and their conversion to aerosol particles. Our findings could help to improve assessments of biosphere-aerosol-climate feedback mechanisms, and the air quality and climate effects of biogenic emissions generally.

  17. Climatology and Characteristics of Aerosol Optical Properties in the Arctic

    NASA Astrophysics Data System (ADS)

    Schmeisser, Lauren; Ogren, John; Backman, John; Asmi, Eija; Andrews, Elisabeth; Jefferson, Anne; Bergin, Michael; Tunved, Peter; Sharma, Sangeeta; Starkweather, Sandra

    2016-04-01

    Within the Arctic, climate forcers like atmospheric aerosols are important contributors to the observed warming and environmental changes in the region. Quantifying the forcing by aerosols in the Arctic is especially difficult, given short aerosol lifetimes, annual variability in illumination and surface albedo, stratified atmospheric conditions, complex feedbacks, and long-range aerosol transport. However, in-situ surface measurements of Arctic aerosol optical properties can be used to constrain variability of light scattering and absorption, identify potential particle sources, and help evaluate the resulting forcing. Data from six WMO Global Atmosphere Watch stations are presented: Alert, Canada (ALT); Barrow, Alaska (BRW); Pallas, Finland (PAL); Summit, Greenland (SUM); Tiksi, Russia (TIK); and Zeppelin Mountain, Norway (ZEP). These sites contribute to the International Arctic System for Observing the Atmosphere (IASOA), which facilitates Arctic-wide data collection and analysis. Climatologies of aerosol optical properties from each station show differences in magnitude and variability of observed parameters. For example, most stations (ALT, BRW, SUM, TIK, ZEP) experience maximum scattering in winter/spring, while PAL exhibits maximum scattering in the summer. The observed range in scattering across these sites is large (almost an order of magnitude) - SUM has the lowest annual median scattering at 0.82 Mm-1 while BRW has the highest at 6.9 Mm-1. A closer look at systematic variability between optical properties at each station, as well as site back trajectories, suggest differences in aerosol processes, sources and transport. The development of consistent climatologies and additional analyses like the ones presented here can help provide a better understanding of trans-Arctic aerosol variability, which can be an asset for improving aerosol models in this unique and remote region.

  18. A large source of low-volatility secondary organic aerosol.

    PubMed

    Ehn, Mikael; Thornton, Joel A; Kleist, Einhard; Sipilä, Mikko; Junninen, Heikki; Pullinen, Iida; Springer, Monika; Rubach, Florian; Tillmann, Ralf; Lee, Ben; Lopez-Hilfiker, Felipe; Andres, Stefanie; Acir, Ismail-Hakki; Rissanen, Matti; Jokinen, Tuija; Schobesberger, Siegfried; Kangasluoma, Juha; Kontkanen, Jenni; Nieminen, Tuomo; Kurtén, Theo; Nielsen, Lasse B; Jørgensen, Solvejg; Kjaergaard, Henrik G; Canagaratna, Manjula; Maso, Miikka Dal; Berndt, Torsten; Petäjä, Tuukka; Wahner, Andreas; Kerminen, Veli-Matti; Kulmala, Markku; Worsnop, Douglas R; Wildt, Jürgen; Mentel, Thomas F

    2014-02-27

    Forests emit large quantities of volatile organic compounds (VOCs) to the atmosphere. Their condensable oxidation products can form secondary organic aerosol, a significant and ubiquitous component of atmospheric aerosol, which is known to affect the Earth's radiation balance by scattering solar radiation and by acting as cloud condensation nuclei. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non-volatile organic vapours, but the sources and compositions of such vapours remain unknown. Here we investigate the oxidation of VOCs, in particular the terpene α-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours. These vapours form at significant mass yield in the gas phase and condense irreversibly onto aerosol surfaces to produce secondary organic aerosol, helping to explain the discrepancy between the observed atmospheric burden of secondary organic aerosol and that reported by many model studies. We further demonstrate how these low-volatility vapours can enhance, or even dominate, the formation and growth of aerosol particles over forested regions, providing a missing link between biogenic VOCs and their conversion to aerosol particles. Our findings could help to improve assessments of biosphere-aerosol-climate feedback mechanisms, and the air quality and climate effects of biogenic emissions generally. PMID:24572423

  19. A large source of low-volatility secondary organic aerosol

    NASA Astrophysics Data System (ADS)

    Ehn, Mikael; Thornton, Joel A.; Kleist, Einhard; Sipilä, Mikko; Junninen, Heikki; Pullinen, Iida; Springer, Monika; Rubach, Florian; Tillmann, Ralf; Lee, Ben; Lopez-Hilfiker, Felipe; Andres, Stefanie; Acir, Ismail-Hakki; Rissanen, Matti; Jokinen, Tuija; Schobesberger, Siegfried; Kangasluoma, Juha; Kontkanen, Jenni; Nieminen, Tuomo; Kurtén, Theo; Nielsen, Lasse B.; Jørgensen, Solvejg; Kjaergaard, Henrik G.; Canagaratna, Manjula; Maso, Miikka Dal; Berndt, Torsten; Petäjä, Tuukka; Wahner, Andreas; Kerminen, Veli-Matti; Kulmala, Markku; Worsnop, Douglas R.; Wildt, Jürgen; Mentel, Thomas F.

    2014-02-01

    Forests emit large quantities of volatile organic compounds (VOCs) to the atmosphere. Their condensable oxidation products can form secondary organic aerosol, a significant and ubiquitous component of atmospheric aerosol, which is known to affect the Earth's radiation balance by scattering solar radiation and by acting as cloud condensation nuclei. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non-volatile organic vapours, but the sources and compositions of such vapours remain unknown. Here we investigate the oxidation of VOCs, in particular the terpene α-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours. These vapours form at significant mass yield in the gas phase and condense irreversibly onto aerosol surfaces to produce secondary organic aerosol, helping to explain the discrepancy between the observed atmospheric burden of secondary organic aerosol and that reported by many model studies. We further demonstrate how these low-volatility vapours can enhance, or even dominate, the formation and growth of aerosol particles over forested regions, providing a missing link between biogenic VOCs and their conversion to aerosol particles. Our findings could help to improve assessments of biosphere-aerosol-climate feedback mechanisms, and the air quality and climate effects of biogenic emissions generally.

  20. Aerosol optical properties and their radiative effects in northern China

    NASA Astrophysics Data System (ADS)

    Li, Zhanqing; Xia, Xiangao; Cribb, Maureen; Mi, Wen; Holben, Brent; Wang, Pucai; Chen, Hongbin; Tsay, Si-Chee; Eck, T. F.; Zhao, Fengsheng; Dutton, E. G.; Dickerson, R. E.

    2007-11-01

    As a fast developing country covering a large territory, China is experiencing rapid environmental changes. High concentrations of aerosols with diverse properties are emitted in the region, providing a unique opportunity for understanding the impact of environmental changes on climate. Until very recently, few observational studies were conducted in the source regions. The East Asian Study of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE) attempts to characterize the physical, optical and chemical properties of the aerosols and their effects on climate over China. This study presents some preliminary results using continuous high-quality measurements of aerosol, cloud and radiative quantities made at the first EAST-AIRE baseline station at Xianghe, about 70 km east of Beijing over a period of one year (September 2004 to September 2005). It was found that the region is often covered by a thick layer of haze (with a yearly mean aerosol optical depth equal to 0.82 at 500 nm and maximum greater than 4) due primarily to anthropogenic emissions. An abrupt "cleanup" of the haze often took place in a matter of one day or less because of the passage of cold fronts. The mean single scattering albedo is approximately 0.9 but has strong day-to-day variations with maximum monthly averages occurring during the summer. Large aerosol loading and strong absorption lead to a very large aerosol radiative effect at the surface (the annual 24-hour mean values equals 24 W m-2), but a much smaller aerosol radiative effect at the top of the atmosphere (one tenth of the surface value). The boundary atmosphere is thus heated dramatically during the daytime, which may affect atmospheric stability and cloud formation. In comparison, the cloud radiative effect at the surface is only moderately higher (-41 W m-2) than the aerosol radiative effect at the surface.

  1. Development and first application of an Aerosol Collection Module (ACM) for quasi online compound specific aerosol measurements

    NASA Astrophysics Data System (ADS)

    Hohaus, Thorsten; Kiendler-Scharr, Astrid; Trimborn, Dagmar; Jayne, John; Wahner, Andreas; Worsnop, Doug

    2010-05-01

    Atmospheric aerosols influence climate and human health on regional and global scales (IPCC, 2007). In many environments organics are a major fraction of the aerosol influencing its properties. Due to the huge variety of organic compounds present in atmospheric aerosol current measurement techniques are far from providing a full speciation of organic aerosol (Hallquist et al., 2009). The development of new techniques for compound specific measurements with high time resolution is a timely issue in organic aerosol research. Here we present first laboratory characterisations of an aerosol collection module (ACM) which was developed to allow for the sampling and transfer of atmospheric PM1 aerosol. The system consists of an aerodynamic lens system focussing particles on a beam. This beam is directed to a 3.4 mm in diameter surface which is cooled to -30 °C with liquid nitrogen. After collection the aerosol sample can be evaporated from the surface by heating it to up to 270 °C. The sample is transferred through a 60cm long line with a carrier gas. In order to test the ACM for linearity and sensitivity we combined it with a GC-MS system. The tests were performed with octadecane aerosol. The octadecane mass as measured with the ACM-GC-MS was compared versus the mass as calculated from SMPS derived total volume. The data correlate well (R2 0.99, slope of linear fit 1.1) indicating 100 % collection efficiency. From 150 °C to 270 °C no effect of desorption temperature on transfer efficiency could be observed. The ACM-GC-MS system was proven to be linear over the mass range 2-100 ng and has a detection limit of ~ 2 ng. First experiments applying the ACM-GC-MS system were conducted at the Jülich Aerosol Chamber. Secondary organic aerosol (SOA) was formed from ozonolysis of 600 ppbv of b-pinene. The major oxidation product nopinone was detected in the aerosol and could be shown to decrease from 2 % of the total aerosol to 0.5 % of the aerosol over the 48 hours of

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

    PubMed

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

    2013-12-17

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

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2013-12-17

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

  5. Aerosol optical properties and radiative effects in the Yangtze Delta region of China

    NASA Astrophysics Data System (ADS)

    Xia, Xiangao; Li, Zhanqing; Holben, Brent; Wang, Pucai; Eck, Tom; Chen, Hongbin; Cribb, Maureen; Zhao, Yanxia

    2007-11-01

    One year's worth of aerosol and surface irradiance data from September 2005 to August 2006 were obtained at Taihu, the second supersite for the East Asian Study of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE). Aerosol optical properties derived from measurements by a Sun photometer were analyzed. The aerosol data were used together with surface irradiance data to quantitatively estimate aerosol effects on surface shortwave radiation (SWR) and photosynthetically active radiation (PAR). The annual mean aerosol optical depth at 500 nm is 0.77, and mean Ångstrom wavelength exponent is 1.17. The annual mean aerosol single scattering albedo and mean aerosol asymmetry factor at 440 nm are 0.90 and 0.72, respectively. Both parameters show a weak seasonal variation, with small values occurring during the winter and larger values during the summer. Clear positive relationships between relative humidity and aerosol properties suggest aerosol hygroscopic growth greatly modifies aerosol properties. The annual mean aerosol direct radiative forcing at the surface (ADRF) is -38.4 W m-2 and -17.8 W m-2 for SWR and PAR, respectively. Because of moderate absorption, the instantaneous ADRF at the top of the atmosphere derived from CERES SSF data is close to zero. Heavy aerosol loading in this region leads to -112.6 W m-2 and -45.5 W m-2 reduction in direct and global SWR, but 67.1 W m-2 more diffuse SWR reaching the surface. With regard to PAR, the annual mean differences in global, direct and diffuse irradiance are -23.1 W m-2, -65.2 W m-2 and 42.1 W m-2 with and without the presence of aerosol, respectively.

  6. Anthropogenic Aerosols and Tropical Precipitation

    NASA Astrophysics Data System (ADS)

    Wang, C.; Kim, D.; Ekman, A. M. L.; Barth, M. C.; Rasch, P. J.

    2009-04-01

    Anthropogenic aerosols can affect the radiative balance of the Earth-atmosphere system and precipitation by acting as cloud condensation nuclei (CCN) or ice nuclei (IN) and thus modifying the optical and microphysical properties as well as lifetimes of clouds. Recent studies have also suggested that the direct radiative effect of anthropogenic aerosols, particularly absorbing aerosols, can perturb the large-scale circulation and cause a significant change in both quantity and distribution of critical tropical precipitation systems ranging from Pacific and Indian to Atlantic Oceans. This effect of aerosols on precipitation often appears in places away from aerosol-concentrated regions and current results suggest that the precipitation changes caused by it could be much more substantial than that by the microphysics-based aerosol effect. To understand the detailed mechanisms and strengths of such a "remote impact" and the climate response/feedback to anthropogenic aerosols in general, an interactive aerosol-climate model has been developed based on the Community Climate System Model (CCSM) of NCAR. Its aerosol module describes size, chemical composition, and mixing states of various sulfate and carbonaceous aerosols. Several model processes are derived based on 3D cloud-resolving model simulations. We have conducted a set of long integrations using the model driven by radiative effects of different combinations of various carbonaceous and sulfate aerosols and their mixtures. The responses of tropical precipitation systems to the forcing of these aerosols are analyzed using both model and observational data. Detailed analyses on the aerosol-precipitation causal relations of two systems: i.e., the Indian summer monsoon and Pacific ITCZ will be specifically presented.

  7. Heterogeneous Uptake of HO2 Radicals onto Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

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

    NASA Astrophysics Data System (ADS)

    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

  9. Validation of MODIS Aerosol Optical Depth Retrieval Over Land

    NASA Technical Reports Server (NTRS)

    Chu, D. A.; Kaufman, Y. J.; Ichoku, C.; Remer, L. A.; Tanre, D.; Holben, B. N.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Aerosol optical depths are derived operationally for the first time over land in the visible wavelengths by MODIS (Moderate Resolution Imaging Spectroradiometer) onboard the EOSTerra spacecraft. More than 300 Sun photometer data points from more than 30 AERONET (Aerosol Robotic Network) sites globally were used in validating the aerosol optical depths obtained during July - September 2000. Excellent agreement is found with retrieval errors within (Delta)tau=+/- 0.05 +/- 0.20 tau, as predicted, over (partially) vegetated surfaces, consistent with pre-launch theoretical analysis and aircraft field experiments. In coastal and semi-arid regions larger errors are caused predominantly by the uncertainty in evaluating the surface reflectance. The excellent fit was achieved despite the ongoing improvements in instrument characterization and calibration. This results show that MODIS-derived aerosol optical depths can be used quantitatively in many applications with cautions for residual clouds, snow/ice, and water contamination.

  10. Effect of photosensitized chemistry on organic aerosol evolution

    NASA Astrophysics Data System (ADS)

    Rouvière, A.; Decarlo, P. F.; Bartels-Rausch, T.; Ammann, M.

    2009-12-01

    Photochemistry in aerosol particles is an emerging new field of atmospheric science. Up to now, photochemical processes in the condensed phase of atmospheric aerosol particles are not well understood. Primary and secondary compounds in the gas and aerosol phase continuously interact and change phase during their or their descendants life time in the atmosphere. Partially oxised aromatic compounds such as aromatic ketones may act as photosensitizer to promote charge and energy transfer to other organic compounds under conditions, where direct photolysis processes of the latter are not possible. The resulting radicals undergo numerous secondary chemical reactions, some of which may lead to polymerization. In this study we show that the presence of a photosensitizer in the aerosol phase leads to significant processing of simple organic compounds such as small organic acids due to exposure to simulated sunlight. The aerosol flow tube experiments were performed in a photoreactor, which was coupled to a chemical ionization mass spectrometer and a scanning mobility particle sizer. For some experiments an aerosol mass spectrometer was also used. We used ammonium sulfate and organic acids as matrix and Benzoyl Benzoic Acid (BBA) as sensitizer. BBA is a well known photosensitizer absorbing in the UV. The results will be shown and discussed.

  11. Regional aerosol properties: Comparisons of boundary layer measurements from ACE 1, ACE 2, Aerosols99, INDOEX, ACE Asia, TARFOX, and NEAQS

    NASA Astrophysics Data System (ADS)

    Quinn, Patricia K.; Bates, Timothy S.

    2005-07-01

    Means and variability of aerosol chemical composition and optical properties are compared for the first and second Aerosol Characterization Experiments (ACE 1 and ACE 2), a cruise across the Atlantic (Aerosols99), the Indian Ocean Experiment (INDOEX), the Asian Aerosol Characterization Experiment (ACE Asia), the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX), and the New England Air Quality Study (NEAQS). These experiments were focused either on the remote marine atmosphere (ACE 1) or areas downwind of continental aerosol source regions including western Europe, North America, Africa, India, and Asia. Presented here are size-segregated concentrations of aerosol mass, sea salt, non-sea-salt (nss) SO4=, NH4+, NO3-, dust, organic carbon (OC), elemental carbon (EC), and nss K+, as well as mass ratios that are commonly used to identify aerosol sources and to assess aerosol processing (Cl- to Na+, OC to nss SO4=, EC to total carbon (TC), EC to nss SO4=, nss K+ to EC, Fe to Al, and Si to Al). Optical properties that are compared include size-segregated scattering, backscattering, and absorption coefficients, and single-scattering albedo at 550 nm. Size-segregated mass scattering and mass absorption efficiencies for the total aerosol and mass extinction efficiencies for the dominant chemical components also are compared. In addition, we present the contribution to light extinction by the dominant chemical components for each region. All data are based on shipboard measurements performed at a relative humidity of 55 ± 5%. Scattering coefficients and single-scattering albedos also are reported at ambient relative humidity (RH) using published values of f(RH). Finally, aerosol optical depths from each region are compared. Identical sampling protocols were used in all experiments in order to eliminate sampling biases and to make the data directly comparable. Major findings include (1) nss SO4= makes up only 16 to 46% of the submicron aerosol mass

  12. Molecular transformations accompanying the aging of laboratory secondary organic aerosol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aging of fresh secondary organic aerosol, generated by alpha-pinene ozonolysis in a flow tube reactor, was studied by passing it through a second reaction chamber where hydroxyl radicals were generated. Two types of experiments were performed: plug injection experiments where the particle mass a...

  13. Evaluation of SAGE II and Balloon-Borne Stratospheric Aerosol Measurements: Evaluation of Aerosol Measurements from SAGE II, HALOE, and Balloonborne Optical Particle Counters

    NASA Technical Reports Server (NTRS)

    Hervig, Mark; Deshler, Terry; Moddrea, G. (Technical Monitor)

    2002-01-01

    Stratospheric aerosol measurements from the University of Wyoming balloonborne optical particle counters (OPCs), the Stratospheric Aerosol and Gas Experiment (SAGE) II, and the Halogen Occultation Experiment (HALOE) were compared in the period 1982-2000, when measurements were available. The OPCs measure aerosol size distributions, and HALOE multiwavelength (2.45-5.26 micrometers) extinction measurements can be used to retrieve aerosol size distributions. Aerosol extinctions at the SAGE II wavelengths (0.386-1.02 micrometers) were computed from these size distributions and compared to SAGE II measurements. In addition, surface areas derived from all three experiments were compared. While the overall impression from these results is encouraging, the agreement can change with latitude, altitude, time, and parameter. In the broadest sense, these comparisons fall into two categories: high aerosol loading (volcanic periods) and low aerosol loading (background periods and altitudes above 25 km). When the aerosol amount was low, SAGE II and HALOE extinctions were higher than the OPC estimates, while the SAGE II surface areas were lower than HALOE and the OPCS. Under high loading conditions all three instruments mutually agree to within 50%.

  14. Comparison of Aerosol Mass Spectrometer and Aerosol Chemical Speciation Monitor Measurements of Secondary Organic Aerosol Formation in Smog Chamber Studies

    NASA Astrophysics Data System (ADS)

    Croteau, P. L.; Hunter, J. F.; Daumit, K. E.; Carrasquillo, A. J.; Cross, E. S.; Canagaratna, M.; Jayne, J.; Worsnop, D. R.; Kroll, J. H.

    2012-12-01

    Thermal vaporization-electron impact ionization (TV-EI) mass spectrometry is a powerful tool for understanding the chemistry of secondary organic aerosol (SOA) formation and atmospheric aging. The Aerodyne Aerosol Mass Spectrometer (AMS) and recently developed Aerosol Chemical Speciation Monitor (ACSM) are two instruments that utilize the same TV-EI technique. The ACSM trades the particle sizing capability, sensitivity, speed, and resolution of the AMS for simplicity, affordability, and ease of operation - enabling stand-alone continuous sampling for extended periods of time. Here we present results of an intercomparison between a high-resolution AMS and an ACSM. Three well-studied SOA formation chamber experiments were conducted: isoprene photooxidation under high NOx conditions, m-xylene photooxidation under high NOx conditions, and α-pinene ozonolysis under low NOx conditions. Comparisons between time-series and mass spectra from these experiments, along with positive matrix factorization analysis results demonstrate that the ACSM, while it does not provide the same level of detail as an AMS, is a suitable tool for exploring the chemistry of SOA formation in chamber studies.

  15. Graphical aerosol classification method using aerosol relative optical depth

    NASA Astrophysics Data System (ADS)

    Chen, Qi-Xiang; Yuan, Yuan; Shuai, Yong; Tan, He-Ping

    2016-06-01

    A simple graphical method is presented to classify aerosol types based on a combination of aerosol optical thickness (AOT) and aerosol relative optical thickness (AROT). Six aerosol types, including maritime (MA), desert dust (DD), continental (CO), sub-continental (SC), urban industry (UI) and biomass burning (BB), are discriminated in a two dimensional space of AOT440 and AROT1020/440. Numerical calculations are performed using MIE theory based on a multi log-normal particle size distribution, and the AROT ranges for each aerosol type are determined. More than 5 years of daily observations from 8 representative aerosol sites are applied to the method to confirm spatial applicability. Finally, 3 individual cases are analyzed according to their specific aerosol status. The outcomes indicate that the new graphical method coordinates well with regional characteristics and is also able to distinguish aerosol variations in individual situations. This technique demonstrates a novel way to estimate different aerosol types and provide information on radiative forcing calculations and satellite data corrections.

  16. Representing Cloud Processing of Aerosol in Numerical Models

    SciTech Connect

    Mechem, D.B.; Kogan, Y.L.

    2005-03-18

    The satellite imagery in Figure 1 provides dramatic examples of how aerosol influences the cloud field. Aerosol from ship exhaust can serve as nucleation centers in otherwise cloud-free regions, forming ship tracks (top image), or can enhance the reflectance/albedo in already cloudy regions. This image is a demonstration of the first indirect effect, in which changes in aerosol modulate cloud droplet radius and concentration, which influences albedo. It is thought that, through the effects it has on precipitation (drizzle), aerosol can also affect the structure and persistence of planetary boundary layer (PBL) clouds. Regions of cellular convection, or open pockets of cloudiness (bottom image) are thought to be remnants of strongly drizzling PBL clouds. Pockets of Open Cloudiness (POCs) (Stevens et al. 2005) or Albrecht's ''rifts'' are low cloud fraction regions characterized by anomalously low aerosol concentrations, implying they result from precipitation. These features may in fact be a demonstration of the second indirect effect. To accurately represent these clouds in numerical models, we have to treat the coupled cloud-aerosol system. We present the following series of mesoscale and large eddy simulation (LES) experiments to evaluate the important aspects of treating the coupled cloud-aerosol problem. 1. Drizzling and nondrizzling simulations demonstrate the effect of drizzle on a mesoscale forecast off the California coast. 2. LES experiments with explicit (bin) microphysics gauge the relative importance of the shape of the aerosol spectrum on the 3D dynamics and cloud structure. 3. Idealized mesoscale model simulations evaluate the relative roles of various processes, sources, and sinks.

  17. Aerosol Size Distribution, Composition, and Hygroscopicity Measurements During CSTRIPE Using an Aerosol Mass Spectrometer and a Dual Differential Mobility Analyzer

    NASA Astrophysics Data System (ADS)

    Bahreini, R.; Varutbangkul, V.; Conant, W. C.; Flagan, R. C.; Seinfeld, J. H.; Buzorius, G.; Jonsson, H. H.

    2003-12-01

    During July 2003, the CIRPAS Twin Otter aircraft was deployed in the CSTRIPE (Coastal STRatocumulus Imposed Perturbation Experiment) field experiment in order to quantify the effects of aerosols on the microphysics and dynamics of marine stratocumulus clouds. In order to characterize the effects of different aerosol types on stratocumulus clouds, various air masses were sampled, including local fire plumes, pollution over the San Joaquin valley, unperturbed marine stratocumulus clouds, and stratocumulus clouds perturbed by seeding flares. Some research flights were also dedicated to characterize the seeding flares in the clear sky. Measurements of aerosol mass distribution and composition, using an Aerodyne Aerosol Mass Spectrometer (AMS), and size distribution and hygroscopic behavior, using a Dual Differential Mobility Analyzer (Dual DMA) with one column at dry conditions and another at a relative humidity of approximately 70 percent, will be presented here. During a number of in-cloud sampling periods, the Counter-flow Virtual Impactor (CVI) was used to select and dry cloud droplets, which were then analyzed by the AMS and the Dual DMA. The AMS composition measurements showed that sulfate and organics comprised most of the mass of the non-refractory components of the aerosol. The DMA showed a mixture of unimodal and bimodal size distributions in most types of air masses. The air mass over the San Joaquin valley, however, showed strong evidence of freshly nucleated particles, with aerosol number concentrations often above 80,000 cm-3.

  18. Exposures to acidic aerosols.

    PubMed

    Spengler, J D; Keeler, G J; Koutrakis, P; Ryan, P B; Raizenne, M; Franklin, C A

    1989-02-01

    Ambient monitoring of acid aerosols in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. Measurements made in Kingston, TN, and Steubenville, OH, resulted in 24-hr H+ ion concentrations exceeding 100 nmole/m3 more than 10 times during summer months. Periods of elevated acidic aerosols occur less frequently in winter months. The H+ determined during episodic conditions in southern Ontario indicates that respiratory tract deposition can exceed the effects level reported in clinical studies. Observed 12-hr H+ concentrations exceeded 550 nmole/m3 (approximately 27 micrograms/m3 H2SO4). The maximum estimated 1-hr concentration exceeded 1500 nmole/m3 for H+ ions. At these concentrations, an active child might receive more than 2000 nmole of H+ ion in 12 hr and in excess of 900 nmole during the hour when H2SO4 exceeded 50 micrograms/m3.

  19. Evolution of stratospheric sulfate aerosol from the 1991 Pinatubo eruption: Roles of aerosol microphysical processes

    NASA Astrophysics Data System (ADS)

    Sekiya, T.; Sudo, K.; Nagai, T.

    2016-03-01

    This study investigates the role of aerosol microphysics in stratospheric sulfate aerosol changes after the 1991 Mount Pinatubo eruption using an atmospheric general circulation model that is coupled interactively with a chemistry module and a modal aerosol microphysical module with three modes. Our model can reproduce the global mean stratospheric aerosol optical depth (SAOD) observed by the Stratospheric Aerosol and Gas Experiment (SAGE) II during June 1991 to January 1993. The model underestimates the observed SAOD before the eruption and after January 1993. The model also underestimates the integrated backscatter coefficient observed by ground-based lidar at Tsukuba, Naha, and Lauder. The modeled effective radius becomes larger (about 0.5 μm) and agrees with the balloon-borne measurements at Laramie, Wyoming (41°N, 105°W). We further investigate effects of the inclusion of evaporation along with the condensation processes and the inclusion of van der Waals and viscous forces in the coagulation processes. The inclusion of evaporation along with the condensation processes reduces the global mean effective radius by up to 0.04 μm and increases the global burden of stratospheric sulfate aerosols (about 15% in late 1993). The inclusion of van der Waals and viscous forces in the coagulation processes increases the global mean effective radius by up to 0.06-0.07 μm and decreases the global burden (15-30% in late 1993). The effects of van der Waals and viscous forces differ between two schemes. However, we do not conclude which simulation is superior because all simulations fall within error bars.

  20. Aerosol Observing System (AOS) Handbook

    SciTech Connect

    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.

  1. Polarimetric remote sensing of aerosol and cloud microphysics from the NASA Glory Aerosol Polarimetry Sensor (APS)

    NASA Astrophysics Data System (ADS)

    Cairns, B.; Chowdhary, J.; Knobelspiesse, K.; Sato, M.; Mishchenko, M.; Travis, L.

    2005-12-01

    Tropospheric aerosols play a crucial role in climate and can cause a climate forcing directly by absorbing and reflecting sunlight, thereby cooling or heating the atmosphere, and indirectly by modifying cloud properties. The indirect aerosol effect may include increased cloud brightness, as aerosols lead to a larger number of smaller cloud droplets (the so-called Twomey effect), and increased cloud cover, as smaller droplets inhibit rainfall and increase cloud lifetime. Both forcings are poorly understood and may represent the largest source of uncertainty about future climate change. In this paper we present results from various field experiments demonstrating the contribution that the multi-angle multi-spectral photopolarimetric remote sensing measurements of the NASA Glory APS will make to the determination of the direct and indirect radiative effects of aerosols. Remote sensing of aerosols from satellites is plagued by the need to make prior assumptions about the composition and size of the aerosols that are present, whether this is to calculate the phase functions of the aerosols for passive remote sensing, or the extinction to backscatter ratio for elastic backscatter lidar measurements. Measurements made by the Research Scanning Polarimeter (RSP) have demonstrated that many of these assumptions can be eliminated using polarimetric remote sensing and that it is possible to retrieve the optical depth, single scattering albedo, refractive index and the location and width of a bimodal size distribution. Moreover, polarimetric remote sensing provides this capability over both land and water surfaces. Measurements from the CLAMS and IHOP field experiments and over smoke from fires in Southern California have been used to demonstrate these capabilities and the ability to estimate the height of the aerosol layer if sufficient aerosol is present. In passive remote sensing of clouds it is generally the case that for water clouds the effective variance of the droplet

  2. Cantera Aerosol Dynamics Simulator

    2004-09-01

    The Cantera Aerosol Dynamics Simulator (CADS) package is a general library for aerosol modeling to address aerosol general dynamics, including formation from gas phase reactions, surface chemistry (growth and oxidation), bulk particle chemistry, transport by Brownian diffusion, thermophoresis, and diffusiophoresis with linkage to DSMC studies, and thermal radiative transport. The library is based upon Cantera, a C++ Cal Tech code that handles gas phase species transport, reaction, and thermodynamics. The method uses a discontinuous galerkinmore » formulation for the condensation and coagulation operator that conserves particles, elements, and enthalpy up to round-off error. Both O-D and 1-D time dependent applications have been developed with the library. Multiple species in the solid phase are handled as well. The O-D application, called Tdcads (Time Dependent CADS) is distributed with the library. Tdcads can address both constant volume and constant pressure adiabatic homogeneous problems. An extensive set of sample problems for Tdcads is also provided.« less

  3. Secondary organic aerosol formation from in-use motor vehicle emissions using a potential aerosol mass reactor.

    PubMed

    Tkacik, Daniel S; Lambe, Andrew T; Jathar, Shantanu; Li, Xiang; Presto, Albert A; Zhao, Yunliang; Blake, Donald; Meinardi, Simone; Jayne, John T; Croteau, Philip L; Robinson, Allen L

    2014-10-01

    Secondary organic aerosol (SOA) formation from in-use vehicle emissions was investigated using a potential aerosol mass (PAM) flow reactor deployed in a highway tunnel in Pittsburgh, Pennsylvania. Experiments consisted of passing exhaust-dominated tunnel air through a PAM reactor over integrated hydroxyl radical (OH) exposures ranging from ∼ 0.3 to 9.3 days of equivalent atmospheric oxidation. Experiments were performed during heavy traffic periods when the fleet was at least 80% light-duty gasoline vehicles on a fuel-consumption basis. The peak SOA production occurred after 2-3 days of equivalent atmospheric oxidation. Additional OH exposure decreased the SOA production presumably due to a shift from functionalization to fragmentation dominated reaction mechanisms. Photo-oxidation also produced substantial ammonium nitrate, often exceeding the mass of SOA. Analysis with an SOA model highlight that unspeciated organics (i.e., unresolved complex mixture) are a very important class of precursors and that multigenerational processing of both gases and particles is important at longer time scales. The chemical evolution of the organic aerosol inside the PAM reactor appears to be similar to that observed in the atmosphere. The mass spectrum of the unoxidized primary organic aerosol closely resembles ambient hydrocarbon-like organic aerosol (HOA). After aging the exhaust equivalent to a few hours of atmospheric oxidation, the organic aerosol most closely resembles semivolatile oxygenated organic aerosol (SV-OOA) and then low-volatility organic aerosol (LV-OOA) at higher OH exposures. Scaling the data suggests that mobile sources contribute ∼ 2.9 ± 1.6 Tg SOA yr(-1) in the United States, which is a factor of 6 greater than all mobile source particulate matter emissions reported by the National Emissions Inventory. This highlights the important contribution of SOA formation from vehicle exhaust to ambient particulate matter concentrations in urban areas.

  4. Atmospheric aerosols: Their Optical Properties and Effects

    NASA Technical Reports Server (NTRS)

    1976-01-01

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

  5. Ice nucleation in sulfuric acid/organic aerosols: implications for cirrus cloud formation

    NASA Astrophysics Data System (ADS)

    Beaver, M. R.; Elrod, M. J.; Garland, R. M.; Tolbert, M. A.

    2006-03-01

    Using an aerosol flow tube apparatus, we have studied the effects of aliphatic aldehydes (C3 to C10) and ketones (C3 and C9) on ice nucleation in sulfuric acid aerosols. Mixed aerosols were prepared by combining an organic vapor flow with a flow of sulfuric acid aerosols over a small mixing time (~60 s) at room temperature. No acid-catalyzed reactions were observed under these conditions, and physical uptake was responsible for the organic content of the sulfuric acid aerosols. In these experiments, aerosol organic content, determined by a Mie scattering analysis, was found to vary with the partial pressure of organic, the flow tube temperature, and the identity of the organic compound. The physical properties of the organic compounds (primarily the solubility and melting point) were found to play a dominant role in determining the mode of nucleation (homogenous or heterogeneous) and the specific freezing temperatures observed. Overall, very soluble, low-melting organics, such as acetone and propanal, caused a decrease in aerosol ice nucleation temperatures when compared with aqueous sulfuric acid aerosol. In contrast, sulfuric acid particles exposed to organic compounds of eight carbons and greater, of much lower solubility and higher melting temperatures, nucleate ice at temperatures above aqueous sulfuric acid aerosols. Organic compounds of intermediate carbon chain length, C4-C7, (of intermediate solubility and melting temperatures) nucleated ice at the same temperature as aqueous sulfuric acid aerosols. Interpretations and implications of these results for cirrus cloud formation are discussed.

  6. Ice nucleation in sulfuric acid/organic aerosols: implications for cirrus cloud formation

    NASA Astrophysics Data System (ADS)

    Beaver, M. R.; Elrod, M. J.; Garland, R. M.; Tolbert, M. A.

    2006-08-01

    Using an aerosol flow tube apparatus, we have studied the effects of aliphatic aldehydes (C3 to C10) and ketones (C3 and C9) on ice nucleation in sulfuric acid aerosols. Mixed aerosols were prepared by combining an organic vapor flow with a flow of sulfuric acid aerosols over a small mixing time (~60 s) at room temperature. No acid-catalyzed reactions were observed under these conditions, and physical uptake was responsible for the organic content of the sulfuric acid aerosols. In these experiments, aerosol organic content, determined by a Mie scattering analysis, was found to vary with the partial pressure of organic, the flow tube temperature, and the identity of the organic compound. The physical properties of the organic compounds (primarily the solubility and melting point) were found to play a dominant role in determining the inferred mode of nucleation (homogenous or heterogeneous) and the specific freezing temperatures observed. Overall, very soluble, low-melting organics, such as acetone and propanal, caused a decrease in aerosol ice nucleation temperatures when compared with aqueous sulfuric acid aerosol. In contrast, sulfuric acid particles exposed to organic compounds of eight carbons and greater, of much lower solubility and higher melting temperatures, nucleate ice at temperatures above aqueous sulfuric acid aerosols. Organic compounds of intermediate carbon chain length, C4-C7, (of intermediate solubility and melting temperatures) nucleated ice at the same temperature as aqueous sulfuric acid aerosols. Interpretations and implications of these results for cirrus cloud formation are discussed.

  7. Organosulfate formation in biogenic secondary organic aerosol.

    PubMed

    Surratt, Jason D; Gómez-González, Yadian; Chan, Arthur W H; Vermeylen, Reinhilde; Shahgholi, Mona; Kleindienst, Tadeusz E; Edney, Edward O; Offenberg, John H; Lewandowski, Michael; Jaoui, Mohammed; Maenhaut, Willy; Claeys, Magda; Flagan, Richard C; Seinfeld, John H

    2008-09-11

    Organosulfates of isoprene, alpha-pinene, and beta-pinene have recently been identified in both laboratory-generated and ambient secondary organic aerosol (SOA). In this study, the mechanism and ubiquity of organosulfate formation in biogenic SOA is investigated by a comprehensive series of laboratory photooxidation (i.e., OH-initiated oxidation) and nighttime oxidation (i.e., NO3-initiated oxidation under dark conditions) experiments using nine monoterpenes (alpha-pinene, beta-pinene, d-limonene, l-limonene, alpha-terpinene, gamma-terpinene, terpinolene, Delta(3)-carene, and beta-phellandrene) and three monoterpenes (alpha-pinene, d-limonene, and l-limonene), respectively. Organosulfates were characterized using liquid chromatographic techniques coupled to electrospray ionization combined with both linear ion trap and high-resolution time-of-flight mass spectrometry. Organosulfates are formed only when monoterpenes are oxidized in the presence of acidified sulfate seed aerosol, a result consistent with prior work. Archived laboratory-generated isoprene SOA and ambient filter samples collected from the southeastern U.S. were reexamined for organosulfates. By comparing the tandem mass spectrometric and accurate mass measurements collected for both the laboratory-generated and ambient aerosol, previously uncharacterized ambient organic aerosol components are found to be organosulfates of isoprene, alpha-pinene, beta-pinene, and limonene-like monoterpenes (e.g., myrcene), demonstrating the ubiquity of organosulfate formation in ambient SOA. Several of the organosulfates of isoprene and of the monoterpenes characterized in this study are ambient tracer compounds for the occurrence of biogenic SOA formation under acidic conditions. Furthermore, the nighttime oxidation experiments conducted under highly acidic conditions reveal a viable mechanism for the formation of previously identified nitrooxy organosulfates found in ambient nighttime aerosol samples. We estimate

  8. Volcanic aerosols and lunar eclipses.

    PubMed

    Keen, R A

    1983-12-01

    The moon is visible during total lunar eclipses due to sunlight refracted into the earth's shadow by the atmosphere. Stratospheric aerosols can profoundly affect the brightness of the eclipsed moon. Observed brightnesses of 21 lunar eclipses during 1960-1982 are compared with theoretical calculations based on refraction by an aerosol-free atmosphere to yield globally averaged aerosol optical depths. Results indicate the global aerosol loading from the 1982 eruption of El Chichón is similar in magnitude to that from the 1963 Agung eruption.

  9. Volcanic aerosols and lunar eclipses.

    PubMed

    Keen, R A

    1983-12-01

    The moon is visible during total lunar eclipses due to sunlight refracted into the earth's shadow by the atmosphere. Stratospheric aerosols can profoundly affect the brightness of the eclipsed moon. Observed brightnesses of 21 lunar eclipses during 1960-1982 are compared with theoretical calculations based on refraction by an aerosol-free atmosphere to yield globally averaged aerosol optical depths. Results indicate the global aerosol loading from the 1982 eruption of El Chichón is similar in magnitude to that from the 1963 Agung eruption. PMID:17776243

  10. Stratospheric aerosols and climatic change

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    Stratospht1ic sulfuric acid particles scatter and absorb sunlight and they scatter, absorb and emit terrestrial thermal radiation. These interactions play a role in the earth's radiation balance and therefore affect climate. The stratospheric aerosols are perturbed by volcanic injection of SO2 and ash, by aircraft injection of SO2, by rocket exhaust of Al2O3 and by tropospheric mixing of particles and pollutant SO2 and COS. In order to assess the effects of these perturbations on climate, the effects of the aerosols on the radiation balance must be understood and in order to understand the radiation effects the properties of the aerosols must be known. The discussion covers the aerosols' effect on the radiation balance. It is shown that the aerosol size distribution controls whether the aerosols will tend to warm or cool the earth's surface. Calculations of aerosol properties, including size distribution, for various perturbation sources are carried out on the basis of an aerosol model. Calculations are also presented of the climatic impact of perturbed aerosols due to volcanic eruptions and Space Shuttle flights.

  11. Satellite Estimates of the Direct Radiative Forcing of Biomass Burning Aerosols Over South America and Africa

    NASA Technical Reports Server (NTRS)

    Christopher, Sundar A.; Wang, Min; Kliche, Donna V.; Berendes, Todd; Welch, Ronald M.; Yang, S.K.

    1997-01-01

    Atmospheric aerosol particles, both natural and anthropogenic are important to the earth's radiative balance. Therefore it is important to provide adequate validation information on the spatial, temporal and radiative properties of aerosols. This will enable us to predict realistic global estimates of aerosol radiative effects more confidently. The current study utilizes 66 AVHRR LAC (Local Area Coverage) and coincident Earth Radiation Budget Experiment (ERBE) images to characterize the fires, smoke and radiative forcings of biomass burning aerosols over four major ecosystems of South America.

  12. Inter-Comparison of ILAS-II Version 1.4 Aerosol Extinction Coefficient at 780 nm with SAGE II, SAGE III, and POAM III Aerosol Data

    NASA Technical Reports Server (NTRS)

    Saitoh, Naoko; Hayashida, S.; Sugita, T.; Nakajima, H.; Yokota, T.; Hayashi, M.; Shiraishi, K.; Kanzawa, H.; Ejiri, M. K.; Irie, H.; Tanaka, T.; Terao, Y.; Kobayashi, H.; Sasano, Y.; Bevilacqua, R.; Randall, C.; Thomason, L.; Taha, G.

    2006-01-01

    The Improved Limb Atmospheric Spectrometer (ILAS) II on board the Advanced Earth Observing Satellite (ADEOS) II observed stratospheric aerosol in visible/near-infrared/infrared spectra over high latitudes in the Northern and Southern Hemispheres. Observations were taken intermittently from January to March, and continuously from April through October, 2003. We assessed the data quality of ILAS-II version 1.4 aerosol extinction coefficients at 780 nm from comparisons with the Stratospheric Aerosol and Gas Experiment (SAGE) II, SAGE III, and the Polar Ozone and Aerosol Measurement (POAM) III aerosol data. At heights below 20 km in the Northern Hemisphere, aerosol extinction coefficients from ILAS-II agreed with those from SAGE II and SAGE III within 10%, and with those from POAM III within 15%. From 20 to 26 km, ILAS-II aerosol extinction coefficients were smaller than extinction coefficients from the other sensors; differences between ILAS-II and SAGE II ranged from 10% at 20 km to 34% at 26 km. ILAS-II aerosol extinction coefficients from 20 to 25 km in February over the Southern Hemisphere had a negative bias (12-66%) relative to SAGE II aerosol data. The bias increased with increasing altitude. Comparisons between ILAS-II and POAM III aerosol extinction coefficients from January to May in the Southern Hemisphere (defined as the non-Polar Stratospheric Cloud (PSC) season ) yielded qualitatively similar results. From June to October (defined as the PSC season ), aerosol extinction coefficients from ILAS-II were smaller than those from POAM III above 17 km, as in the case of the non-PSC season; however, ILAS-II and POAM III aerosol data were within 15% of each other from 12 to 17 km.

  13. Characteristics and Global Impact of Aerosols from Southern Africa and Eastern Asia

    NASA Technical Reports Server (NTRS)

    Chin, Mian

    2004-01-01

    Supported mainly by the NASA GACP and ACMAP, we have made significant progress in the global modeling of tropospheric aerosols and their precursors in the past few years, especially in the development of the GOCART model, simulation of anthropogenic and natural aerosols, data analysis of field observations and satellite retrievals, assessment of global and regional budgets, estimate of aerosol direct radiative forcing, and aerosol forecasting and data analysis for the ACE-Asia field experiment. Our results and findings are summarized in Chin et al. Model calculated multiple-year optical thickness for individual and total aerosols are at internet. These results have been frequently used by other groups, for example, to impose initial conditions for regional models, provide dust source functions for other global models, supply aerosol fields for chemistry and climate models, help data group interpret their measurements, select monitoring sites for ground observation network, and assist satellite retrievals.

  14. Detecting cross-equatorial wind change as a fingerprint of climate response to anthropogenic aerosol forcing

    NASA Astrophysics Data System (ADS)

    Wang, Hai; Xie, Shang-Ping; Tokinaga, Hiroki; Liu, Qinyu; Kosaka, Yu

    2016-04-01

    Anthropogenic aerosols are a major driver of the twetieth century climate change. In climate models, the aerosol forcing, larger in the Northern than Southern Hemispheres, induces an interhemispheric Hadley circulation. In support of the model result, we detected a robust change in the zonal mean cross-equatorial wind over the past 60 years from ship observations and reanalyses, accompanied by physically consistent changes in atmospheric pressure and marine cloud cover. Single-forcing experiments indicate that the observed change in cross-equatorial wind is a fingerprint of aerosol forcing. This zonal mean mode follows the evolution of global aerosol forcing that is distinct from regional changes in the Atlantic sector. Atmospheric simulations successfully reproduce this interhemispheric mode, indicating the importance of sea surface temperature mediation in response to anthropogenic aerosol forcing. As societies awaken to reduce aerosol emissions, a phase reversal of this interhemispheric mode is expected in the 21st century.

  15. Bench-scale evaluation of aerosol delivery for biostimulation and bioaugmentation in the vadose zone.

    PubMed

    Hall, Richard J; Murdoch, Lawrence C; Freedman, David L; Looney, Brian B; Riha, Brian D

    2015-04-01

    Aerosol delivery was evaluated for distributing biostimulation and bioaugmentation amendments in vadose zones. This technique involves transporting amendments as micron-scale aerosol droplets in injected gas. Microcosm experiments were designed to characterize reductive dechlorination of trichloroethene (TCE) under unsaturated conditions when delivering components as aerosols. Delivering amendments and/or microbes as aqueous aerosols resulted in complete dechlorination of TCE, similar to controls operated under saturated conditions. Reductive dechlorination was achieved with manual injection of a bioaugmentation culture suspended in soybean oil into microcosms. However, aerosol delivery of the culture in soybean oil induced little reductive dechlorination activity. Overall, the results indicate that delivery as aqueous aerosols may be a viable option for delivery of amendments to enhance vadose zone bioremediation at the field-scale.

  16. Aerosol single scattering albedo and its contribution to radiative forcing dung EAST- AIRE

    NASA Astrophysics Data System (ADS)

    Lee, K.; Li, Z.

    2007-12-01

    Quantification of aerosol single scattering albedo (SSA) can improve determining aerosol radiative property. Combination technique using MODIS and ground-based Hazemeter measurement data by the East Asian Study of Tropospheric Aerosols: an International Regional Experiment (EAST-AIRE) over China is proposed to retrieve SSA. The accuracy of the retrieval of SSA increases with the aerosol loading and the uncertainties in the SSA retrieval are 0.02~0.03 (AOT=1.0) and up to 0.03~0.05 (AOT=0.5) at 0.47¥ìm, respectively. The comparison of one- year data of retrieved SSA values with those from AERONET inversion product are ~0.03 (RMSD) and ~0.02 (mean bias), respectively. Estimated SSA values were range from 0.89 to 0.93 over the study area. Since SSA is an important factor of aerosol radiative forcing, these will help to understood the study of aerosol climate effects.

  17. Distinct effects of anthropogenic aerosols on the East Asian summer monsoon between multidecadal strong and weak monsoon stages

    NASA Astrophysics Data System (ADS)

    Xie, Xiaoning; Wang, Hongli; Liu, Xiaodong; Li, Jiandong; Wang, Zhaosheng; Liu, Yangang

    2016-06-01

    Because industrial emissions of anthropogenic aerosols over East Asia have greatly increased in recent decades, the interactions between atmospheric aerosols and the East Asian summer monsoon (EASM) have attracted enormous attention. To further understand the aerosol-EASM interaction, we investigate the impacts of anthropogenic aerosols on the EASM during the multidecadal strong (1950-1977) and weak (1978-2000) EASM stages using the Community Atmospheric Model 5.1. Numerical experiments are conducted for the whole period, including the two different EASM stages, with present day (PD, year 2000) and preindustrial (PI, year 1850) aerosol emissions, as well as the observed time-varying aerosol emissions. A comparison of the results from PD and PI shows that, with the increase in anthropogenic aerosols, the large-scale EASM intensity is weakened to a greater degree (-9.8%) during the weak EASM stage compared with the strong EASM stage (-4.4%). The increased anthropogenic aerosols also result in a significant reduction in precipitation over North China during the weak EASM stage, as opposed to a statistically insignificant change during the strong EASM stage. Because of greater aerosol loading and the larger sensitivity of the climate system during weak EASM stages, the aerosol effects are more significant during these EASM stages. These results suggest that anthropogenic aerosols from the same aerosol emissions have distinct effects on the EASM and the associated precipitation between the multidecadal weak and strong EASM stages.

  18. Investigation of the relative fine and coarse mode aerosol loadings and properties in the Southern Arabian Gulf region

    NASA Astrophysics Data System (ADS)

    Kaku, Kathleen C.; Reid, Jeffrey S.; Reid, Elizabeth A.; Ross-Langerman, Kristy; Piketh, Stuart; Cliff, Steven; Al Mandoos, Abdulla; Broccardo, Stephen; Zhao, Yongjing; Zhang, Jianglong; Perry, Kevin D.

    2016-03-01

    The aerosol chemistry environment of the Arabian Gulf region is extraordinarily complex, with high concentrations of dust aerosols from surrounding deserts mixed with anthropogenic aerosols originating from a large petrochemical industry and pockets of highly urbanized areas. Despite the high levels of aerosols experienced by this region, little research has been done to explore the chemical composition of both the anthropogenic and mineral dust portion of the aerosol burden. The intensive portion of the United Arab Emirates Unified Aerosol Experiment (UAE2), conducted during August and September 2004 was designed in part to resolve the aerosol chemistry through the use of multiple size-segregated aerosol samplers. The coarse mode mass (derived by subtracting the PM2.5 aerosol mass from the PM10 mass) is largely dust at 76% ± 7% of the total coarse mode mass, but is significantly impacted by anthropogenic pollution, primarily sulfate and nitrate. The PM2.5 aerosol mass also contains a large dust burden, at 38% ± 26%, but the anthropogenic component dominates. The total aerosol burden has significant impact not only on the atmosphere, but also the local population, as the air quality levels for both the PM10 and PM2.5 aerosol masses reached unhealthy levels for 24% of the days sampled.

  19. The impact of aerosols on the climate and its changes in China

    NASA Astrophysics Data System (ADS)

    Li, Z.

    2013-05-01

    Heavy and widespread presence of aerosols could impinge significantly on regional and global climate depending on aerosol distribution, transport and evolution of optical, physical and chemical properties. To unravel the impact and interactions between aerosols and climate of China, several field experiments have been conducted in the region. Besides, numerous studies are being carried out using the long-term (up to 50 years) routine meteorological measurements. Findings will be summarized from two China-US joint experiments: the East Asian Study of Tropospheric Aerosols: an International Regional Experiment (EAST-AIRE) in 2005 and the Atmospheric Radiation Measurements (ARM) Mobile Facility deployment in 2008 (AMF-China), as well as from analyses of routine data. The experiments have produced a wealth of measurements pertaining to aerosol properties, meteorological regimes, cloud, radiation and precipitation in order to gain insights into the potential mechanism by which aerosols affect and interact with the monsoon regime. By taking advantage of the field observation data, many evidences of aerosol's direct, indirect and semi-direct effects are revealed, with the bulk published in two special sections of the J. Geophy. Res. In addition, some features of the impact of increasing aerosols on the long-term tre