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Sample records for aerosol experiments nspp

  1. Sodium oxide and uranium oxide aerosol experiments: NSPP Tests 106-108 and Tests 204-207, data record report

    SciTech Connect

    Adams, R.E.; Kress, T.S.; Tobias, M.L.

    1981-03-01

    This data record report describes three sodium oxide aerosol tests and four uranium oxide aerosol tests conducted in the Nuclear Safety Pilot Plant project at Oak Ridge National Laboratory. The goal of this project is to establish the validity (or level of conservatism) of the aerosol behavioral code, HAARM-3, and follow-on codes under development at the Battelle Columbus Laboratories for the US Nuclear Regulatory Commission. Descriptions of the seven tests with tables and graphs summarizing the results are included. 92 figs.

  2. Uranium oxide and sodium oxide aerosol experiments: NSPP mixed-oxide tests 303-307, data record report. [LMFBR

    SciTech Connect

    Adams, R.E.; Kress, T.S.; Tobias, M.L.

    1982-10-01

    This data record report summarizes five tests, involving mixtures of uranium oxide and sodium oxide aerosols, conducted in the Nuclear Safety Pilot Plant project at Oak Ridge National Laboratory. The goal of this project is to establish the validity (or level of conservatism) of the aerosol behavioral code, HAARM-3, and follow-on codes under development at Battelle Columbus Laboratories for the US Nuclear Regulatory Commission. Descriptions of the five tests with tables and graphs summarizing the results are included.

  3. 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.

  4. AEROSOL CHARACTERIZATION WITH CENTRIFUCAL AEROSOL SPECTROMETERS: THEORY AND EXPERIMENT

    EPA Science Inventory

    A general mathematical model describing the motion of particles in aerosol centrifuges has been developed. t has been validated by comparisons of theoretically predicted calibration sites with experimental data from tests sizing aerosols in instruments of three different spiral d...

  5. 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.

  6. Anthropogenic Aerosol Effects on Sea Surface Temperatures: Mixed-Layer Ocean Experiments with Explicit Aerosol Representation

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Anthropogenic aerosols affect the Earth's radiative balance both through direct and indirect effects. These effects can lead to a reduction of the incoming solar radiation at the surface, i.e. dimming, which may lead to a change in sea surface temperatures (SST) or SST pattern. This, in turn, may affect precipitation patterns. The goal of the present work is to achieve an estimate of the equilibrium SST changes under anthropogenic aerosol forcing since industrialisation. We show preliminary results from mixed-layer ocean (MLO) experiments with explicit aerosol representation performed with ECHAM6-HAM. The (fixed) MLO heat flux into the deep ocean was derived from atmosphere only runs with fixed climatological SSTs (1961-1990 average) and present day (year 2000) aerosols and GHG burdens. Some experiments we repeated with an alternative MLO deep ocean heat flux (based on pre-industrial conditions) to test the robustness of our results with regard to this boundary condition. The maximum surface temperature responses towards anthropogenic aerosol and GHG forcing (separately and combined) were derived on a global and regional scale. The same set of experiments was performed with aerosol and GHG forcings representative of different decades over the past one and a half centuries. This allows to assess how SST patterns at equilibrium changed with changing aerosol (and GHG) forcing. Correlating SST responses with the change in downward clear-sky and all-sky shortwave radiation provides a first estimate of the response to anthropogenic aerosols. Our results show a clear contrast in hemispheric surface temperature response, as expected from the inter-hemispheric asymmetry of aerosol forcing The presented work is part of a project aiming at quantifying the effect of anthropogenic aerosol forcing on SSTs and the consequences for global precipitation patterns. Results from this study will serve as a starting point for further experiments involving a dynamic ocean model, which

  7. The Charged Aerosol Release Experiment (CARE) Program

    NASA Astrophysics Data System (ADS)

    Bernhardt, Paul; Scales, Wayne; Sternovsky, Zoltan; Kelley, Michael; Hysell, David; Holzworth, Robert

    A new experiment called the Charged Aerosol Release Experiment (CARE) employs the release of dust in the upper atmosphere to form a dusty plasma in space. Two solid rocket motors strapped side-by-side in opposition will provide a pin-wheel high speed dust dispenser for the CARE experiment. A spherical dust cloud will form as a radial expansion around the CARE dust release module. The release will occur between 200 and 250 km altitude in the F-region where the 10 to 1000 nm diameter particles will become charged by electron attachment. As the charged dust particle stream through the ionosphere, plasma irregularities will be produced by streaming and fluid plasma instabilities. The plasma turbulence will driven by large electric fields at the surface of the cloud resulting from the separation of unmagnetized negatively charge dust from the background positive ions which are tied to magnetic field lines. In addition, two stream instabilities from the charge particles moving through the plasma will cause plasma wave structures. The effects of the CARE dust release will be diagnosed with in situ electric field booms, dust detectors, and Langmuir probes. Remote sensing of the CARE release will involve ground backscatter radars in the HF, VHF, and UHF frequency ranges. At late times, the dust cloud will settle into the mesosphere where an artificial mesospheric cloud will be formed. Satellite imagery using the AIM satellite will measure the long-term dispersal of the artificial dust cloud. The results of the CARE experiment will be compared with radar, optical and rocket measurements of natural polar mesospheric clouds.

  8. 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.

  9. Beijing Olympics as an aerosol field experiment

    NASA Astrophysics Data System (ADS)

    Cermak, J.; Knutti, R.

    2009-05-01

    During the 2008 Olympic Summer Games, emission reductions were enforced in Beijing to improve air quality. Here we explore their effect on the regional aerosol load. We compare satellite-retrieved aerosol optical thickness (AOT) of that period with previous years, both in absolute terms and in a neural network approach taking into account the meteorological conditions. A statistically significant reduction of aerosol load is found in Beijing that decreases in magnitude and significance with increasing region size. Locally, the aerosol load (log(AOT)) was about 0.4 to 0.75 standard deviations below the levels expected for the prevailing meteorological situation. The small size of this effect relative to meteorological variability highlights the importance of regional aerosol transport.

  10. Formation of highly oxygenated organic aerosol in the atmosphere: Insights from the Finokalia Aerosol Measurement Experiments

    NASA Astrophysics Data System (ADS)

    Hildebrandt, Lea; Kostenidou, Evangelia; Mihalopoulos, Nikos; Worsnop, Douglas R.; Donahue, Neil M.; Pandis, Spyros N.

    2010-12-01

    Aged organic aerosol (OA) was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiments (FAME-08 and FAME-09), which were part of the EUCAARI intensive campaigns. Quadrupole aerosol mass spectrometers (Q-AMSs) were employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1), and to estimate the extent of oxidation of the OA. The experiments provide unique insights into ambient oxidation of aerosol by measuring at the same site but under different photochemical conditions. NR-PM1 concentrations were about a factor of three lower during FAME-09 (winter) than during FAME-08 (summer). The OA sampled was significantly less oxidized and more variable in composition during the winter than during the early summer. Lower OH concentrations in the winter were the main difference between the two campaigns, suggesting that atmospheric formation of highly oxygenated OA is associated with homogeneous photochemical aging.

  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. 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.

  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.; 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.

  14. 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.

  15. MELCOR 1. 8. 1 assessment: LACE aerosol experiment LA4

    SciTech Connect

    Kmetyk, L.N.

    1991-09-01

    The MELCOR code has been used to simulate LACE aerosol experiment LA4. In this test, the behavior of single- and double-component, hygroscopic and nonhygroscopic, aerosols in a condensing environment was monitored. Results are compared to experimental data, and to CONTAIN calculations. Sensitivity studies have been done on time step effects and machine dependencies; thermal/hydraulic parameters such as condensation on heat structures and on pool surface, and radiation heat transfer; and aerosol parameters such as number of MAEROS components and sections assumed, the degree to which plated aerosols are washed off heat structures by condensate film draining, and the effect of non-default values for shape factors and diameter limits. 9 refs., 50 figs., 13 tabs.

  16. 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:

  17. Aerosol effect on Umkehr ozone profiles using Stratospheric Aerosol and Gas Experiment II measurements

    NASA Technical Reports Server (NTRS)

    Newchurch, M. J.; Cunnold, D. M.

    1994-01-01

    This study examines 1211 cases of coincident ozone profiles derived from 1164 Umkehrs and 928 Stratospheric Aerosol and Gas Experiment II (SAGE II) profiles within 1000 km and 12 hours between October 1984 and April 1989 to study the stratospheric-aerosol effect on Umkehr ozone profiles. Because of the close correspondence of stratospheric aerosol optical depth at the SAGE II-measured 0.525-micrometer wavelength and the extrapolated 0.32 Umkehr wavelength determined in this study we use the 0.525-micrometer data to determine the aerosol effect on Umkehr profiles. At the 95% confidence level, we find the following errors to the Umkehr ozone amounts: in Umkehr layer 9 (-2.9 +/- 2.1), layer 8 (-2.3 +/- 1.1), layer 7 (0.1 +/- 1.1), layer 6 (2.2 +/- 1.0), layer 5 (-1.5 +/- 0.8), and layer 4 (-2.4 +/- 1.7) in percent ozone amount per 0.01 stratospheric aerosol optical depth. These results agree with previous theoretical and empirical studies within their respective error bounds in layers 9, 8, and 7. The results in layers 6, 5, and 4 differ significantly from those in previous works. Using only those eight stations with more than 47 coincidences results in mean aerosol effects that are not significantly different from the 14-station results. Because SAGE II and Umkehr produce different ozone retrievals in layer 9 and because the intralayer correlation of SAGE II ozone and aerosol in layer 9 is nonzero, one must exercise some caution in attributing the entire SAGE II-Umkehr difference in this layer to an aerosol effect.

  18. 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

  19. The Finokalia Aerosol Measurement Experiment - 2008 (FAME-08): an overview

    NASA Astrophysics Data System (ADS)

    Pikridas, M.; Bougiatioti, A.; Hildebrandt, L.; Engelhart, G. J.; Kostenidou, E.; Mohr, C.; Prévôt, A. S. H.; Kouvarakis, G.; Zarmpas, P.; Burkhart, J. F.; Lee, B.-H.; Psichoudaki, M.; Mihalopoulos, N.; Pilinis, C.; Stohl, A.; Baltensperger, U.; Kulmala, M.; Pandis, S. N.

    2010-07-01

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

  20. The Finokalia Aerosol Measurement Experiment - 2008 (FAME-08): an overview

    NASA Astrophysics Data System (ADS)

    Pikridas, M.; Bougiatioti, A.; Hildebrandt, L.; Engelhart, G. J.; Kostenidou, E.; Mohr, C.; Prevot, A. S. H.; Kouvarakis, G.; Zarmpas, P.; Burkhart, J. F.; Lee, B.-H.; Psichoudaki, M.; Mihalopoulos, N.; Pilinis, C.; Stohl, A.; Baltensperger, U.; Kulmala, M.; Pandis, S. N.

    2010-03-01

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

  1. 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

  2. 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

  3. 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

  4. Aerosol Climate Effects: Local Radiative Forcing and Column Closure Experiments

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Bergstrom, Robert W.; Kinne, S. A.

    2000-01-01

    In an effort to reduce uncertainties in climate change predictions, experiments are being planned and conducted to measure anthropogenic aerosol properties and effects, including effects on radiative fields. The global average, direct anthropogenic aerosol effect on upwelling shortwave fluxes is estimated to be about +1/2 W/sq m, whereas errors in flux changes measured with airborne and spaceborne radiometers are 2 to 8 W/sq m or larger. This poses the question of whether flux changes expected in field experiments will be large enough to measure accurately. This paper obtains a new expression for the aerosol-induced change in upwelling flux, compares it to two-stream and adding-doubling (AD) results, and uses all three methods to estimate expected flux changes. The new expression accounts for the solar zenith angle dependences of aerosol transmission and reflection, as well as of surface albedo, all of which can have a strong effect in determining flux changes measured in field experiments. Despite its relative simplicity, the new expression gives results similar to previous two-stream results. Relative to AD results, it agrees within a few watts per square meter for the intermediate solar elevation angles where the flux changes peak (roughly 10 to 30 degrees), but it has negative errors for higher Sun and positive errors for lower Sun. All three techniques yield aerosol-induced changes in upwelling flux of +8 to +50 W/sq m for aerosol midvisible optical depths of 0.1 to 0.5. Because such aerosol optical depths occur frequently off the U.S. and European Atlantic coasts in summer, the flux changes they induce should be measurable by airborne, and possibly by spaceborne, radiometers, provided sufficient care is taken in experiment design (including measurements to separate aerosol radiative effects from those of absorbing gases). The expected flux changes are about 15 to 100 times larger than the global average flux change expected for the global average

  5. 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.

  6. 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.

  7. Skylab experiment performance evaluation manual. Appendix P: Experiment T003 inflight aerosol analysis (DOT/MSFC)

    NASA Technical Reports Server (NTRS)

    Purushotham, K. S.

    1972-01-01

    A series of analyses is presented for experiment T003, inflight aerosol analysis, to be used for evaluating the performance of the Skylab corollary experiments under preflight, inflight, and post-flight conditions. Experiment contingency plan workaround procedure and malfunction analyses are presented in order to assist in making the experiment operationally successful.

  8. Preliminary Results from the Smoke Aerosol Measurement Experiment - Reflight

    NASA Astrophysics Data System (ADS)

    Urban, D. L.; Ruff, G. A.; Mulholland, G. W.; Yuan, Z.; Cleary, T.; Yang, J.; Meyer, M. E.; Bryg, V. M.

    2012-01-01

    Preliminary results are presented from the Reflight of the Smoke Aerosol Measurement Experiment (SAME- R) 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. Particle size determinations were made using aerosol instruments and by capturing particles for ground based examination in a Transmission Electron Microscope (TEM). Overall the majority of the average smoke particle sizes were found to be in the 200 to 400 nanometer range with the some of the quiescent cases producing substantially larger particles. When combined with particle morphology data from the TEM analysis, these results can be used to guide the design of future smoke detectors.

  9. 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

  10. 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

  11. 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.

  12. Measurement of the ambient organic aerosol volatility distribution: application during the Finokalia Aerosol Measurement Experiment (FAME-2008)

    NASA Astrophysics Data System (ADS)

    Lee, B. H.; Kostenidou, E.; Hildebrandt, L.; Riipinen, I.; Engelhart, G. J.; Mohr, C.; Decarlo, P. F.; Mihalopoulos, N.; Prevot, A. S. H.; Baltensperger, U.; Pandis, S. N.

    2010-07-01

    A variable residence time thermodenuder (TD) was combined with an Aerodyne Aerosol Mass Spectrometer (AMS) and a Scanning Mobility Particle Sizer (SMPS) to measure the volatility distribution of aged organic aerosol in the Eastern Mediterranean during the Finokalia Aerosol Measurement Experiment in May of 2008 (FAME-2008). A new method for the quantification of the organic aerosol volatility distribution was developed combining measurements of all three instruments together with an aerosol dynamics model. Challenges in the interpretation of ambient thermodenuder-AMS measurements include the potential resistances to mass transfer during particle evaporation, the effects of particle size on the evaporated mass fraction, the changes in the AMS collection efficiency and particle density as the particles evaporate partially in the TD, and finally potential losses inside the TD. Our proposed measurement and data analysis method accounts for all of these problems combining the AMS and SMPS measurements. The AMS collection efficiency of the aerosol that passed through the TD was found to be approximately 10% lower than the collection efficiency of the aerosol that passed through the bypass. The organic aerosol measured at Finokalia is approximately 2 orders of magnitude less volatile than fresh laboratory-generated biogenic secondary organic aerosol. This low volatility is consistent with its highly oxygenated AMS mass spectrum. The results are found to be highly sensitive to the mass accommodation coefficient of the evaporating species.

  13. 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

  14. 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.

  15. 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.

  16. Measurement of the ambient organic aerosol volatility distribution: application during the Finokalia Aerosol Measurement Experiment (FAME-2008)

    NASA Astrophysics Data System (ADS)

    Lee, B. H.; Kostenidou, E.; Hildebrandt, L.; Riipinen, I.; Engelhart, G. J.; Mohr, C.; Decarlo, P. F.; Mihalopoulos, N.; Prevot, A. S. H.; Baltensperger, U.; Pandis, S. N.

    2010-12-01

    A variable residence time thermodenuder (TD) was combined with an Aerodyne Aerosol Mass Spectrometer (AMS) and a Scanning Mobility Particle Sizer (SMPS) to measure the volatility distribution of aged organic aerosol in the Eastern Mediterranean during the Finokalia Aerosol Measurement Experiment in May of 2008 (FAME-2008). A new method for the quantification of the organic aerosol volatility distribution was developed combining measurements of all three instruments together with an aerosol dynamics model. Challenges in the interpretation of ambient thermodenuder-AMS measurements include the potential resistances to mass transfer during particle evaporation, the effects of particle size on the evaporated mass fraction, the changes in the AMS collection efficiency and particle density as the particles evaporate partially in the TD, and finally potential losses inside the TD. Our proposed measurement and data analysis method accounts for all of these problems combining the AMS and SMPS measurements. The AMS collection efficiency of the aerosol that passed through the TD was found to be approximately 10% lower than the collection efficiency of the aerosol that passed through the bypass. The organic aerosol measured at Finokalia is approximately 2 or more orders of magnitude less volatile than fresh laboratory-generated monoterpene (α-pinene, β-pinene and limonene under low NOx conditions) secondary organic aerosol. This low volatility is consistent with its highly oxygenated AMS mass spectrum. The results are found to be highly sensitive to the mass accommodation coefficient of the evaporating species. This analysis is based on the assumption that there were no significant reactions taking place inside the thermodenuder.

  17. LMFBR source term experiments in the Fuel Aerosol Simulant Test (FAST) facility

    SciTech Connect

    Petrykowski, J.C.; Longest, A.W.

    1985-01-01

    The transport of uranium dioxide (UO/sub 2/) aerosol through liquid sodium was studied in a series of ten experiments in the Fuel Aerosol Simulant Test (FAST) facility at Oak Ridge National Laboratory (ORNL). The experiments were designed to provide a mechanistic basis for evaluating the radiological source term associated with a postulated, energetic core disruptive accident (CDA) in a liquid metal fast breeder reactor (LMFBR). Aerosol was generated by capacitor discharge vaporization of UO/sub 2/ pellets which were submerged in a sodium pool under an argon cover gas. Measurements of the pool and cover gas pressures were used to study the transport of aerosol contained by vapor bubbles within the pool. Samples of cover gas were filtered to determine the quantity of aerosol released from the pool. The depth at which the aerosol was generated was found to be the most critical parameter affecting release. The largest release was observed in the baseline experiment where the sample was vaporized above the sodium pool. In the nine ''undersodium'' experiments aerosol was generated beneath the surface of the pool at depths varying from 30 to 1060 mm. The mass of aerosol released from the pool was found to be a very small fraction of the original specimen. It appears that the bulk of aerosol was contained by bubbles which collapsed within the pool. 18 refs., 11 figs., 4 tabs.

  18. 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

  19. 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.

  20. 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.

  1. MAPTIP experiment, marine aerosol properties and thermal imager performance

    SciTech Connect

    Eijk, A.M.J. van; Leeuw, G. de; Jensen, D.R.

    1994-12-31

    During the fall of 1993, a field experimental study on Marine Aerosol Properties and Thermal Imager Performance (MAPTIP) was conducted in the Dutch coastal waters. The objectives of the MAPTIP trial were: (1) to improve and validate vertical marine aerosol models by providing an extensive set of aerosol and meteorological measurements, within a coastal environment, at different altitudes and for a range of meteorological conditions; (2) to make aerosol and meteorological observations in the first 10 m above the ocean surface with a view to extending existing aerosol models to incorporate near-surface effects; (3) to assess marine boundary layer effects on thermal imaging systems. Aerosol and meteorological instruments, as well as thermal imagers and calibrated targets, were used at several platforms and locations. Measurements have been made of atmospheric turbulence and refractivity effects at wavelengths in the IR and visible, to assess the marine boundary layer effects on the degradation of thermal images. Calibrated targets at different altitudes were observed to the maximum observable range under a wide variety of conditions in both the 3--5 and 8--12 gm bands, These data will be used for the development and validation of IRST models and IR ship signature models with the view of determining the effects of marine-generated aerosols, turbulence and meteorological profiles on their performance.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Laboratory experiments on the formation and recoil jet transport of aerosol by laser ablation

    NASA Astrophysics Data System (ADS)

    Hirooka, Yoshi; Tanaka, Kazuo A.; Imamura, Keisuke; Okazaki, Katsuya

    2016-05-01

    In a high-repetition rate inertial fusion reactor, the first wall will be subjected to repeated ablation along with pellet implosions, which then leads to the formation of aerosol to scatter and/or deflect laser beams for the subsequent implosion, affecting the overall reactor performance. Proposed in the present work is a method of in-situ directed transport of aerosol particles by the use of laser ablation-induced jet recoil momenta. Lithium and carbon are used as the primary ablation targets, the former of which is known to form aerosol in the form of droplet, and the latter of which tends to form carbon nanotubes. Laboratory-scale experiments have been conducted to irradiate airborne aerosol particles with high-intensity laser to produce ablation-induced jet. Data have indicated a change in aerosol flow direction, but only in the case of lithium.

  7. 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

  8. 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

  9. Visible and near infrared observation on the Global Aerosol Backscatter Experiment (GLOBE)

    NASA Technical Reports Server (NTRS)

    Spinhirne, James D.; Cavanaugh, John F.; Chudamani, S.; Bufton, Jack L.; Sullivan, Robert J.

    1991-01-01

    The Global Aerosol Backscatter Experiment (GLOBE) was intended to provide data on prevailing values of atmospheric backscatter cross-section. The primary intent was predicting the performance of spaceborne lidar systems, most notably the Laser Atmospheric Wind Sounder (LAWS) for the Earth Observing System (EOS). The second and related goal was to understand the source and characteristics of atmospheric aerosol particles. From the GLOBE flights, extensive data was obtained on the structure of clouds and the marine planetary boundary layer. A notable result for all observations is the consistency of the large increases in the aerosol scattering ratio for the marine boundary layer. Other results are noted.

  10. 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.

  11. Aerosol lofting from sea breeze during the Indian Ocean Experiment

    NASA Astrophysics Data System (ADS)

    Verma, S.; Boucher, O.; Venkataraman, C.; Reddy, M. S.; Müller, D.; Chazette, P.; Crouzille, B.

    2006-04-01

    This work was carried out to understand the mechanisms leading to lofting and large-scale advection of aerosols over the Indian Ocean region due to interaction of the sea breeze with the northeast monsoon winds along the west coast of India. European Centre for Medium-Range Weather Forecasts (ECMWF) wind fields for the months of February and March 1999 were analyzed at various times of day. Intense sea breeze activity was observed at 1200 UT (1730 local time) along the west coast of India with average intensity larger in March than in February. The sea breeze was seen to extend inland deeper in March than in February. Lofting of air observed as high as 800 hPa (approximately 2 km above sea level) could lead to entrainment of aerosols into the free troposphere and long-range transport. Upward motion of air was observed everywhere along the west coast of India (from 8° to 20°N), on average higher in March than in February, because of convergence between the sea breeze and the synoptic-scale flow. A region of intense lofting of air and well-defined convergence was observed along the coast of the Karnataka region (12°-16°N). A simulation with a general circulation model nudged with ECMWF data indicated that the intrusion of marine air masses with low concentrations of organic matter is seen as deep as 64 km inland in the evening (1500 UT). Intrusion of the sea-salt plume is seen to a maximum distance of around 200 km from 1500 until 2300 UT. A well-developed lofted layer of aerosols as high as 3 km was also simulated during sea breeze activity along the west coast of India. The general circulation model simulation shows a clear diurnal evolution of the vertical profile of the aerosol extinction coefficient at Goa but fails to reproduce several features of the lidar observations, for example, the marked diurnal variability of the upper layers between 1 and 3 km. However, the model simulates a diurnal cycle at the surface (0-0.7 km) that is not apparent in lidar

  12. 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).

  13. Diffusion battery sampling of sulfuric acid aerosols formed in oleum spill experiments

    SciTech Connect

    Tang, I N; Wong, W T; Munkelwitz, H R

    1980-01-01

    Fuming sulfuric acid (oleum) is one of several hazardous chemicals routinely transported in bulk quantities on US waterways. In the event of a marine accident, a large amount of the cargo acid could suddenly be released into water, resulting in the formation of a dense sulfuric acid cloud. Experiments were carried out in the laboratory to study the factors controlling the extent of acid aerosol formation under conditions likely to occur in maritime spill accidents. A Sinclair-type diffusion battery was used for aerosol sizing. In this presentation, a brief discussion of an improved nonlinear iterative inversion method for the analysis of diffusion battery data is given. Experimental results obtained with monodisperse test aerosols and sulfuric acid aerosols formed during oleum spills are presented. It is shown that the diffusion battery, coupled with the inversion technique, is capable of sizing particles up to 0.8 ..mu..m in diameter.

  14. Experiments with the assimilation of fine aerosols using an ensemble Kalman filter

    NASA Astrophysics Data System (ADS)

    Pagowski, Mariusz; Grell, Georg A.

    2012-11-01

    In a series of experiments we issue forecasts of fine aerosol concentration over the coterminous USA and southern Canada using the Weather Research and Forecasting - Chemistry model initialized with 3D-VAR or ensemble Kalman filter (EnKF) assimilation methods. Assimilated observations include surface measurements of fine aerosols from the United States Environmental Protection Agency AIRNow Data Exchange program. Evaluation statistics calculated over a month-and-half-long summer period demonstrate the advantage of EnKF over 3D-VAR and point to the limitations of applying a simple aerosol parameterization for predicting air quality over the forecast area. Strategies for further improvement of forecasting aerosol concentrations are discussed.

  15. Experience and Challenges in Implementing Stratospheric Aerosol Gas Experiment on Meteor-3M Platform

    NASA Technical Reports Server (NTRS)

    Habib, Shahid; Newsom, Jerry; Rawls, Richard

    2001-01-01

    Implementation of Stratospheric Aerosol Gas Experiment (SAGE) is a joint science mission between the Rosavioskosmos, also called Russian Aviation and Space Agency (RASA) and the National Aeronautics and Space Administration (NASA). Under the global collaboration agreement established by President Clinton and Yeltsin in 1995 between the United States and Russia, space was one of the major areas identified for joint scientific collaboration. There were several collaborative projects identified under space, earth, human exploration of space and aeronautics. SAGE was one of the key Earth Science instruments selected common to both countries' interests in ozone research. SAGE has a long space heritage, and four earlier versions of this instrument have flown in space for the last 15-year period. It has provided a vital ozone and aerosol data in the mid latitudes and has contributed in the overall ozone depletion research. SAGE II, the fourth instrument has been flying in space on NASA's Earth Radiation Budget Satellite (ERBS) for the last 14 years. Ball Aerospace built the instrument under Langley Research Center's (LaRC) management. SAGE III for Russian Meteor-3M mission is a third generation design with more spectral bands, elaborate data gathering and storage and intelligent terrestrial software. The Russian collaboration required a complete integration of SAGE III on the Russian Meteor-3M satellite and a launch on a Zenit-2 launch vehicle manufactured in Ukraine. The whole complex is scheduled to be launched from Baikonur cosmodrome in early 2001. This cooperative mission has presented a number of management, technical and logistical challenges on both sides. This paper makes an attempt to review and document such experiences.

  16. Chemical Composition and Cloud Condensation Nuclei Properties of Marine Aerosols during the 2005 Marine Stratus Experiment

    NASA Astrophysics Data System (ADS)

    Lee, Y.; Hudson, J.; Daum, P.; Springston, S.; Wang, J.; Senum, G.; Alexander, L.; Jayne, J.; Hubbe, J.

    2006-12-01

    Marine aerosol chemical composition and cloud condensation nuclei (CCN) spectrum were determined on board the DOE G1 aircraft during the Marine Stratus Experiment conducted over the coastal waters between Point Reyes National Seashore and Monterey Bay, California, in July 2005. Aerosol components, including sea-salt- (sodium, chloride, magnesium, methansulfonate) and terrestrial/pollution-derived (ammonium, sulfate, nitrate, organics, potassium, and calcium) were measured using the particle-into-liquid sampler-ion chromatography technique and an Aerodyne AMS at a time resolution of 4 min and 30 s, respectively, both covering the size range of ~0.08 to 1.5 micrometers. The CCN spectrum was determined at a 1-s time resolution covering a supersaturation range between 0.02% and 1%. The accumulation mode particle size- number distribution was measured using a passive cavity aerosol spectrometer probe; the cloud droplet size- number distribution was determined using a Cloud Aerosol Probe. During the campaign sulfate/organic aerosols were always present, sea-salt aerosols were observed on half of the flights, and no dust or biomass burning contribution was noted as calcium and potassium were always below their limits-of-detection. Based on CCN spectra and cloud droplet number concentrations, the typical supersaturation of the marine stratus clouds was ~0.06%, corresponding to a CCN critical diameter between 0.1 and 0.2 micrometer. This large critical diameter makes the aerosol chemical composition measured appropriate for investigating the CCN properties and marine stratus clouds. We note that while sea-salt aerosols and sulfate aerosols were most likely externally mixed, the ensemble exhibits similar CCN properties irrespective of the relative mass concentrations of these two types of aerosols, owing partly to the similar activation properties of NaCl and (NH4)2SO4 aerosols, and that sea-salt particles were larger but fewer, accounting for a small fraction of cloud

  17. 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

  18. 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

  19. Titan aerosol and gas experiment for the Huygens Probe

    NASA Technical Reports Server (NTRS)

    Carle, G. C.; Kojiro, D. R.; Oberbeck, V.; Ohara, B. J.; Pollack, J. B.; Valentin, J. R.; Bar-Nun, A.; Cohen, M. J.; Ferris, J. P.; Greenberg, J. M.

    1991-01-01

    The Cassini Mission is a joint undertaking of NASA and the European Space Agency (ESA) to explore the Saturnian System with a Saturn Orbiter and a Titan Probe. The launch vehicle and the Saturn Orbiter are the responsibility of NASA while the Huygens Probe (detachable Titan Probe) is the responsibility of ESA. The spacecraft will be launched in 1996 and the Huygens Probe will arrive at Titan in 2003. The Cassini Mission-Huygens Probe provides a unique opportunity to obtain detailed information about the atmosphere and, possibly, the surface of Titan. Titan possesses a substantial nitrogen atmosphere containing methane and many other organic compounds. Aerosols play an important role in the atmospheric processes on Titan. The Huygens Probe offers an opportunity to determine how organic particles are formed and grow which will clarify their role on Earth. A powerful analytical instrument, capable of addressing the above technology and other science questions, was recently proposed for the Huygens Probe. It is comprised of an aerosol and gas sampler and processor, and a gas chromatograph-ion mobility spectrometer. The instrument will be able to measure complex organics that make up the collected aerosols to the approximate 1 ppm level. Gases will be measured to approximately 10 ppb. Because the Titan atmosphere is expected to be quite complex, a gas chromatograph-ion mobility spectrometer is used to provide unequivocal identification of the components of the analytes. Further details of the science question to be investigated and the proposed instrument are described. The expected results and their implications are also addressed.

  20. 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.

  1. 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.

  2. Aerosol-Cloud Interactions Evaluated with Aircraft Measurements during the Marine Stratus Experiment (MASE)"

    NASA Astrophysics Data System (ADS)

    Conant, W. C.; Arnott, P.; Bucholtz, A.; Buzorius, G.; Chuang, P. Y.; Jonsson, H. H.; Murphy, S. M.; Rissman, T. A.; Small, J. D.; Sorooshian, A.; Varutbangkul, V.; Flagan, R. C.; Seinfeld, J. H.

    2005-12-01

    In this presentation we explore how aerosols influence the microphysical, dynamical, and radiative properties of marine stratocumulus clouds. We address these aerosol-cloud interactions using data collected by the CIRPAS Twin Otter aircraft during the MASE (Marine Stratus Experiment) campaign, which was conducted off the coast of northern California in July of this year. The otter was instrumented to measure aerosol number concentration, size distribution from 15 nm - 2500 nm, composition (TOF-AMS; PILS), and light absorption. Furthermore, an array of optical probes on the aircraft provided detailed information on the cloud microphysics, including droplet concentration, size distribution, liquid water content and precipitation size distribution. Pyranometers measuring upwelling and downwelling solar irradiance (0.3 μm - 3.5 μm) mounted on a stabilized radiometer platform were used to obtain cloud albedo immediately above the region that was being profiled. Localized (2-20 km wide) regions of high aerosol concentration in the marine boundary layer (MBL) were found and identified as "ship tracks", although no coincident features were immediately apparent in the visible satellite images. Vertical profiles were conducted by the Twin Otter within and on both sides of each ship track to obtain the contrast in aerosol and cloud properties. The ship emissions enhanced aerosol number concentration by factors ranging from 2 to more than 10. They contribute almost entirely to sulfate aerosol -- there was virtually no change in organic aerosol concentration measured by the Aerodyne TOF-AMS or light absorption measured by a photoacoustic instrument within the tracks. The ship emissions are found to have a significant impact on the cloud microphysics, including nearly a doubling of droplet concentration and a reduction in effective radius. The change in droplet dispersion is found to be important in understanding the indirect effect. Cloud albedo tended to be slightly enhanced

  3. 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.

  4. The Stratospheric Aerosol and Gas Experiment III instrument proposed for EOS - A conceptual design

    NASA Technical Reports Server (NTRS)

    Mauldin, L. E.; Mccormick, M. P.; Zawodny, J. M.; Mcmaster, L. R.; Chu, W. P.; Gustafson, J. C.; Maddrea, G. L.

    1989-01-01

    This paper describes the Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument proposed for the Earth Observing System (EOS), which is designed to monitor the vertical distribution of stratospheric aerosols, ozone, water vapor, nitrogen dioxide, and temperature by measuring the extinction and scattering of solar radiation in the 03 to 1.6 micron range through the atmosphere. The SAGE III employs proven concepts which have evolved from the SAM II, SAGE, and SAGE II programs. The launch is scheduled for the summer of 1996. The SAGE II block diagram is included.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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).

  10. 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.

    2014-05-01

    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 forest, 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, aiming to investigate the impacts of biomass burning emissions on climate, air quality, and numerical weather prediction over South America. The campaign took place during the dry season and the transition to the wet season in September/October 2012. During most of the campaign, the site was impacted by regional biomass burning pollution (average CO mixing ratio of 0.6 ppm), occasionally superimposed by intense (up to 2 ppm of CO), freshly emitted biomass burning plumes. Aerosol number concentrations ranged from ∼1000 cm-3 to peaks of up to 35 000 cm-3 during biomass burning (BB) events, corresponding to an average submicron mass mean concentrations of 13.7 μg m-3 and peak concentrations close to 100 μg m-3. Organic aerosol strongly dominated the submicron non-refractory composition, with an average concentration of 11.4 μg m-3. The inorganic species, NH4, SO4, NO3, and Cl, were observed on average at concentrations of 0.44, 0.34, 0.19, and 0.01 μg m-3, respectively. Equivalent Black Carbon (BCe) ranged from 0.2 to 5.5 μg m-3, with an average concentration of 1.3 μg m-3. During BB peaks, organics accounted for over 90% of total mass (submicron non-refractory plus BCe), among the highest values described in the literature. We examined the ageing of Biomass Burning Organic Aerosol (BBOA) using the changes in the H : C and O : C ratios, and found that throughout most of the aerosol processing (O : C ≅ 0

  11. Aerosol Composition, Chemistry, and Source Characterization during the 2008 VOCALS Experiment

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    Chemical composition of fine aerosol particles over the northern Chilean coastal waters was determined on board the US DOE G-1 aircraft during the VOCALS (VAMOS Ocean-Cloud-Atmosphere-Land Study) field experiment between October 16 and November 15, 2008. Chemical species determined included SO42-, NO3-, NH4+, and total organics (Org) using an Aerodyne Aerosol Mass Spectrometer, and SO42-, NO3-, NH4+, Na+, Cl-, CH3SO3-, Mg2+, Ca2+, and K+ 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 ~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 believed to be externally mixed with the acidic sulfate aerosols. Nitrate was observed only on sea-salt particles, consistent with adsorption of HNO3 on non-acidic sea-salt aerosols, responsible partly 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 in the study domain were substantial (~0.5 - ~3 μg/m3) with a strong gradient (highest near the shore decreasing with distance from land), and the ocean-emitted dimethylsulfide and its unique oxidation product, CH3SO3-, were very low (i.e., ≤ 40 parts per trillion and <0.05 μg/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

  12. 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.

  13. The CalWater 2 - ARM Cloud Aerosol Precipitation Experiment (ACAPEX)

    NASA Astrophysics Data System (ADS)

    Leung, L. Y.; Prather, K. A.; Ralph, F. M.; Rosenfeld, D.; Spackman, J. R.; Fairall, C. W.; DeMott, P. J.; Fan, J.; Zhao, C.

    2014-12-01

    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. 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. While ARs are responsible for a large fraction of heavy precipitation in the western U.S. 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. In January - March 2015, the ARM Cloud Aerosol Precipitation Experiment (ACAPEX) field campaign will take place in northern California. Joined with CalWater 2, the field campaign aims to improve understanding and modeling of large-scale dynamics and cloud and precipitation processes associated with ARs and aerosol-cloud interactions that influence precipitation variability and extremes in the western U.S. We will implement an observational strategy consisting of the use of land and offshore assets to monitor (1) the evolution and structure of ARs from near their regions of development, (2) long range transport of aerosols in eastern North Pacific and potential interactions with ARs, and (3) how aerosols from long-range transport and local sources influence cloud and precipitation in the U.S. West Coast where ARs make landfall and post-frontal clouds are frequent. This presentation will provide an overview of the science questions and hypotheses to be addressed by CalWater 2/ACAPEX, review key results from prior studies, and discuss recent findings from

  14. 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.

  15. 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.

  16. A new inversion for Stratospheric Aerosol and Gas Experiment II data

    NASA Astrophysics Data System (ADS)

    Rusch, D. W.; Randall, C. E.; Callan, M. T.; Horanyi, M.; Clancy, R. T.; Solomon, S. C.; Oltmans, S. J.; Johnson, B. J.; Koehler, U.; Claude, H.; de Muer, D.

    1998-04-01

    We describe a new inversion algorithm for retrieving ozone densities and aerosol extinctions from Stratospheric Aerosol and Gas Experiment (SAGE) II measurements. The primary differences between the new algorithm and the current operational SAGE II inversion are the order of the species and altitude inversions, and the methods used to calculate aerosol extinction and remove saturated signals. Ozone densities retrieved at altitudes from 15 to 30 km using the new algorithm are compared to those from the operational SAGE II inversion, as well as to ozone densities from coincident balloon ozonesonde measurements at four different locations in the northern hemisphere between 1984 and 1991 for low to medium stratospheric aerosol loading conditions. The results of the comparison show that the ozone densities resulting from the operational and new algorithms agree to within 1% above 22 km. Below 22 km, the new results are lower than the operational results by up to 30%, depending on altitude and location. At all four stations the new results agree better with the sondes, decreasing the SAGE II/sonde differences by a factor of 2 or more.

  17. 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.

  18. Moisture dynamics in the cloudy and polluted tropical atmosphere: The Cloud Aerosol Radiative Forcing Dynamics Experiment (CARDEX)

    NASA Astrophysics Data System (ADS)

    Wilcox, E. M.; Thomas, R. M.; Praveen, P. S.; Pistone, K.; Bender, F.; Feng, Y.; Ramanathan, V.

    2012-12-01

    Aerosols are well known to modify the microphysical properties of clouds. This modification is expected to yield brighter clouds that cover a greater area. However, observations from satellites show little inter-hemispheric difference in cloud optical thickness and liquid water path in spite of the clear inter-hemispheric difference in aerosol optical thickness. Furthermore, comparisons of observations with global atmospheric models suggest that models that parameterize the mechanisms of aerosol nucleation of cloud drops but do not resolve cloud-scale dynamics may be overestimating the magnitude of aerosol effects on cloud radiative forcing. Resolving these discrepancies requires a deeper understanding of the factors determining the transport of moisture to the cloud layer and the effects of aerosols on that transport. Towards this goal, we have conducted a new field experiment to study the moisture dynamics in the boundary layer and lower troposphere of the polluted and cloudy tropical atmosphere. The Cloud Aerosol Radiative Forcing Dynamics Experiment (CARDEX) was conducted during the winter of 2012 at the Maldives Climate Observatory - Hanimaadhoo in the tropical northern Indian Ocean during the period of extensive outflow of the South Asian pollution. Pollution in the CARDEX region has been well documented to both modify the microphysical properties of low clouds and strongly absorb solar radiation with significant consequences for the lower atmosphere and surface radiative energy budgets. Three unmanned aerial vehicles (UAVs) flew nearly 60 research flights instrumented to measure turbulent latent and sensible heat fluxes, aerosol concentrations, and cloud microphysical properties. Airborne measurements were enhanced with continuous surface monitoring of surface turbulent heat fluxes, aerosol concentrations and physical properties, surface remote sensing of cloud water amount and aerosol profiles, and model analyses of aerosols and dynamics with WRFchem. This

  19. 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

  20. Influence of moisture on the behavior of aerosols

    SciTech Connect

    Adams, R.E.; Longest, A.W.; Tobias, M.L.

    1986-01-01

    The behavior of aerosols assumed to be characteristic of those generated during light water reactor (LWR) accident sequences and released into containment has been studied in the Nuclear Safety Pilot Plant (NSPP) located at the Oak Ridge National Laboratory (ORNL). It has been observed that in a saturated steam-air environment a change occurs in the shape of aerosol agglomerates of U/sub 3/O/sub 8/ aerosol, Fe/sub 2/O/sub 3/ aerosol, and mixed U/sub 3/O/sub 8/-Fe/sub 2/O/sub 3/ aerosol from branched-chain to spherical, and that the rate of reduction in the airborne aerosol mass concentration is increased relative to the rate observed in a dry atmosphere. The effect of a steam-air environment on the behavior of concrete aerosol is different. The shape of the agglomerated concrete aerosol is intermediate between branched-chain and spherical and the effect on the rate of reduction in airborne mass concentration appears to be slight. In a related project the shape of an agglomerated Fe/sub 2/O/sub 3/ aerosol was observed to change from branched-chain to spherical at, or near, 100% relative humidity.

  1. 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.

  2. 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

  3. 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.

  4. Physical and optical properties of mineral dust aerosol during the Dust and Biomass-burning Experiment

    NASA Astrophysics Data System (ADS)

    Osborne, S. R.; Johnson, B. T.; Haywood, J. M.; Baran, A. J.; Harrison, M. A. J.; McConnell, C. L.

    2008-12-01

    We present aircraft measurements of dust aerosol during the Dust and Biomass-burning Experiment (DABEX), a project affiliated with the African Monsoon Multidisciplinary Analysis. DABEX took place between 13 January and 3 February 2006 in Sahelian west Africa, with the aircraft based at Niamey, Niger. The data set is augmented with Aerosol Robotic Network (AERONET) data. A mineral dust layer below 1-2 km (sourced from the north) and an overlying biomass burning (BB) layer (sourced from anthropogenic fires to the south) was observed on all days, although variability was observed in both layers. There is evidence of ozone loss within the dust, but with CO levels between 140 and 170 ppbv some history of combustion has occurred. Size distribution of the dust is compared with that of the BB aerosol and with dust measured near Senegal, during the Dust Outflow and Deposition to the Ocean (DODO-1) experiment. For accurate representation of the optical properties, five log-normals to the size distribution across sizes 0.05-5 μm are required, although two log-normals are adequate. The single scattering albedo was almost purely scattering, with values of 0.99 ± 0.01. During the strongest dust events the dust contribution to the column optical depth was 75-80%, compared to a DABEX mean of 50%. The aircraft-derived optical depth varied between 0.19 and 1.07, with the dust-only contribution between 0.07 and 0.81. AERONET optical depth trends are in good agreement with aircraft during DABEX, albeit with a bias to higher aircraft values. Retrieved AERONET aerosol size distributions show variable agreement with the aircraft. Differences between Versions 1 and 2 of the AERONET algorithm are highlighted.

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. Trace Gases and Aerosol in the Boundary Layer of the Northern Asia: TROICA Experiments

    NASA Astrophysics Data System (ADS)

    Elanksy, N. F.; Aloyan, A. E.; Berezina, E. V.; Elokhov, A. S.; Brenninkmeijer, C. A.; Kopeikin, V. M.; Moeseenko, K. B.; Lavrova, O. V.; Pankratova, N. V.; Safronov, A. N.; Shumsky, R. A.; Skorokhod, A. I.; Tarasova, O. A.; Vivchar, A. V.; Grisenko, A. M.

    2007-12-01

    The TROICA experiment (Transcontinental Observations Into the Chemistry of the Atmosphere) started in 1995. A mobile railroad laboratory is being used for measurements of atmospheric gases, aerosol, solar radiation and meteorological parameters. The laboratory wagon is directly coupled to the locomotive of a passenger train traveling along electrified railroads of Russia. Eleven expeditions have been conducted to the moment of which nine were performed along the Trans-Siberian railroad from Moscow to Vladivostok (around 9300 km). One expedition was North-South between Murmansk and Kislovodsk, and one was around the mega-city of Moscow. The huge coverage of the continental regions and the repetition of the expeditions provide unique information on processes controlling variability of the key trace gases (O3, NOx, CO, CO2, CH4, some VOCs) and aerosols with high temporal and spatial resolution over different scales from continental to local (hundreds meters). Multiple crossings of settlements allowed determining typical variations of surface gases and aerosol concentrations within cities and their plumes. 222Rn concentration data were used for estimates of CO, CH4 and CO2 nocturnal fluxes from the soil and vegetation. Impacts of different factors, like Western Siberian gas and oil industry, forest fires, transboundary air pollution transport and some other can be evaluated based on the measurement data by comparing them with results of model output and hence can be used for model validation. Emissions of the atmospheric CO and CH4 were studied in several expeditions using isotopes analysis.

  10. Stratospheric Aerosol and Gas Experiments 1 and 2: Comparisons with ozonesondes

    NASA Technical Reports Server (NTRS)

    Veiga, Robert E.; Cunnold, Derek M.; Chu, William P.; McCormick, M. Patrick

    1995-01-01

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

  11. Aerosol and cloud sensing with the lidar in-space technology experiment (LITE)

    NASA Astrophysics Data System (ADS)

    Winker, David M.; McCormick, Michael P.

    1994-12-01

    The Lidar In-space Technology Experiment (LITE) is a multi-wavelength backscatter lidar developed by NASA Langley Research Center to fly on the Space Shuttle. The LITE instrument is built around a three-wavelength Nd:YAG laser and a 1-meter diameter telescope. The laser operates at 10 Hz and produces about 500 mJ per pulse at 1064 nm and 532 nm, and 150 mJ per pulse at 355 nm. The objective of the LITE program is to develop the engineering processes required for space lidar and to demonstrate applications of space-based lidar to remote sensing of the atmosphere. The LITE instrument was designed to study a wide range of cloud and aerosol phenomena. To this end, a comprehensive program of scientific investigations has been planned for the upcoming mission. Simulations of on-orbit performance show the instrument has sufficient sensitivity to detect even thin cirrus on a single-shot basis. Signal averaging provides the capability of measuring the height and structure of the planetary boundary layer, aerosols in the free troposphere, the stratospheric aerosol layer, and density profiles to an altitude of 40 km. The instrument has successfully completed a ground-test phase and is scheduled to fly on the Space Shuttle Discovery for a 9- day mission in September 1994.

  12. Aerosol and cloud sensing with the Lidar In-space Technology Experiment (LITE)

    NASA Technical Reports Server (NTRS)

    Winker, D. M.; McCormick, M. P.

    1994-01-01

    The Lidar In-space Technology Experiment (LITE) is a multi-wavelength backscatter lidar developed by NASA Langley Research Center to fly on the Space Shuttle. The LITE instrument is built around a three-wavelength ND:YAG laser and a 1-meter diameter telescope. The laser operates at 10 Hz and produces about 500 mJ per pulse at 1064 nm and 532 nm, and 150 mJ per pulse at 355 nm. The objective of the LITE program is to develop the engineering processes required for space lidar and to demonstrate applications of space-based lidar to remote sensing of the atmosphere. The LITE instrument was designed to study a wide range of cloud and aerosol phenomena. To this end, a comprehensive program of scientific investigations has been planned for the upcoming mission. Simulations of on-orbit performance show the instrument has sufficient sensitivity to detect even thin cirrus on a single-shot basis. Signal averaging provides the capability of measuring the height and structure of the planetary boundary layer, aerosols in the free troposphere, the stratospheric aerosol layer, and density profiles to an altitude of 40 km. The instrument has successfully completed a ground-test phase and is scheduled to fly on the Space Shuttle Discovery for a 9-day mission in September 1994.

  13. 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.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Emerging research has identified two phenomena that play key roles in the variability of the water supply and the incidence of extreme precipitation events along the West Coast of the United States. These phenomena include the role of (1) atmospheric rivers (ARs) in delivering much of the precipitation associated with major storms along the U.S. West Coast, and (2) aerosols—from local sources as well as those transported from remote continents—and their modulating effects on western U.S. precipitation. A better understanding of these processes is needed to reduce uncertainties in weather predictions and climate projections of extreme precipitation and its effects, including the provision of beneficial water supply. This presentation summarizes the science objectives and strategies to address gaps associated with (1) the evolution and structure of ARs including cloud and precipitation processes and air-sea interaction, and (2) aerosol interaction with ARs and the impact on precipitation, including locally-generated aerosol effects on orographic precipitation along the U.S. West Coast. Observations are proposed for multiple winter seasons as part of a 5-year broad interagency vision referred to as CalWater 2 to address these science gaps (http://esrl.noaa.gov/psd/calwater). In January-February 2015, a field campaign has been planned consisting of a targeted set of aircraft and ship-based measurements and associated evaluation of data in near-shore regions of California and in the eastern Pacific. In close coordination with NOAA, DOE's Atmospheric Radiation Measurement (ARM) program is also contributing air and shipborne facilities for ACAPEX (ARM Cloud Aerosol and Precipitation Experiment), a DOE-sponsored study complementing CalWater 2. Ground-based measurements from NOAA's HydroMeteorological Testbed (HMT) network in California and aerosol chemical instrumentation at Bodega Bay, California have been designed to add important near surface-level context for the

  16. 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.

  17. 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

  18. Pampre : a new laboratory experiment to better understand the physico-chemical processes of Titan aerosols formation and growth

    NASA Astrophysics Data System (ADS)

    Szopa, C.; Cernogora, G.; Boufendi, L.; Correia, J. J.; Coll, P.

    2003-04-01

    Titan s atmosphere contains aerosols issued from the organic chemistry induced by the photochemistry of N2 and CH4, the major gaseous atmospheric compounds. These organic aerosols are important as they : i) have a significant influence on the properties of the atmosphere, linked to their optical properties; ii) represent the best known example of transition from the gaseous to the solid phase by chemistry; iii) represent the most complex organics produced in Titan s atmosphere, making them particularly interesting from an exo/astrobiological point of view. However, few direct information are available about them, and their processes of formation and growth are not well understood. In order to bring answers to these questions, we developed a new type of laboratory simulation which is dedicated to better understand the physico-chemical processes involved in the formation and growth of the aerosols. The main originality of this experiment (named PAMPRE) comes from its ability to produce aerosols in volume, as they are maintained in levitation thanks to an electric force compensating gravity, whereas the other similar experiments produce tholins on the reactors walls. Thus, one should produce analogs of Titan s aerosols within representative conditions. Moreover, beyond the ex-situ analyses generally led to characterize the aerosols properties with conventional techniques (MEB, GC-MS), the experimental set-up allows to operate in situ studies of the reactive plasma by UV-vis spectroscopy, in order to deduce the electron energy distribution function which have to be compared with the sun spectrum. Beyond the characterization of the aerosols properties and formation, this experiment will also provide information and materials that will be used to operate the calibrations of the Aerosol and Collector Pyrolyser and Gas Chromatograph-Mass Spectrometer experiments of the Cassini-Huygens mission, and to develop the ICAPS-IMPF facility which should be present in the ISS within

  19. Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) 2011: Design and Highlights

    NASA Astrophysics Data System (ADS)

    Russell, L. M.; Sorooshian, A.; Seinfeld, J.; Albrecht, B. A.; Nenes, A.; Ahlm, L.; Chen, Y.; Craven, J. S.; Coggon, M.; Frossard, A. A.; Jung, E.; Lin, J. J.; Metcalf, A. R.; Modini, R.; Muelmenstaedt, J.; Shingler, T.; Song, S.; Wang, Z.; Wonaschuetz, A.

    2011-12-01

    Aerosol-cloud-radiation interactions are widely held to be the largest single source of uncertainty in climate model projections of future climate change due to increasing anthropogenic emissions. The underlying causes of this uncertainty among modeled predictions of climate are the gaps in our fundamental understanding of cloud processes. There has been significant progress with both observations and models on these important questions. However, while the qualitative aspects of the indirect effects of aerosols on clouds are well known, the quantitative representation of these processes is nontrivial and limits our ability to represent them in global climate models. The Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) 2011 was a targeted aircraft campaign with embedded modeling studies, using the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft and the R/V Point Sur in July 2011 off the coast of Monterey, California, with a full payload of instruments to measure particle and cloud number, mass, composition, and water uptake distributions. To date, the global models lack (i) accurate aerosol particle activation, with the resulting implications for the profiles of supersaturation, vertical velocity, liquid water content, and drop distribution; (ii) realistic microphysical growth and precipitation processes that control the formation and impacts of drizzle on cloud structure, lifetime, and particle concentration; and (iii) eddy-based transport processes that control the effects of entrainment on cloud thickness and lifetime as well as the dispersion of aerosol plumes. These are basic scientific issues that have not been addressed by climate models or by geoengineering proposals that involve perturbing marine stratocumulus. In this talk, we summarize three central aspects of the collaborative E-PEACE design and the resulting highlights: 1. Controlled particle sources were used to separate particle-induced feedbacks

  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. The THS Experiment: Ex Situ Analyses of Titan's Aerosol Analogs Produced at Low Temperature (200K)

    NASA Astrophysics Data System (ADS)

    Sciamma-O'Brien, E. M.; Upton, K. T.; Beauchamp, J. L.; Salama, F.

    2014-12-01

    In the study presented here, we used the COSmIC/Titan Haze Simulation (THS) experiment, an experimental platform developed to study Titan's atmospheric chemistry at low temperature, to produce aerosols representative of the early stages of Titan's aerosol formation. In the 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). Because of the pulsed nature of the plasma, the residence time of the gas in the discharge is only a few microseconds, which leads to a truncated chemistry and allows for the study of the first and intermediate steps of the chemistry. Different N2-CH4-based gas mixtures can be injected in the plasma, with or without the addition of heavier precursors present as trace elements on Titan, in order to monitor the evolution of the chemical growth. 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. In a recently published study, a mass spectrometry analysis of the gas phase has demonstrated that the THS is a unique tool to probe the first and intermediate steps of Titan's atmospheric chemistry at Titan-like temperature. In particular, the mass spectra obtained in a N2-CH4-C2H2-C6H6 mixture are relevant for comparison to Cassini's CAPS-IBS instrument. Here we present the results of a complementary study of the solid phase. Scanning Electron Microscopy images have shown that aggregates produced in N2-CH4-C2H2-C6H6 mixtures are much larger (up to 5 μm in diameter) than those produced in N2-CH4 mixtures (0.1-0.5 μm). Direct Analysis in Real Time mass spectrometry (DART-MS) combined with Collision Induced Dissociation (CID) have detected the presence of aminoacetonitrile, a precursor of glycine, in the THS

  3. Horizontal variability of aerosol optical properties observed during the ARCTAS airborne experiment

    NASA Astrophysics Data System (ADS)

    Shinozuka, Y.; Redemann, J.; Russell, P. B.; Livingston, J. M.; Clarke, A. D.; Podolske, J. R.

    2010-12-01

    The properties of tropospheric aerosol and gas vary within a satellite grid cell and between ground-based instruments. This hinders comparison between satellite and suborbital measurements of different spatial scales as well as their applications to climate and air quality studies. This paper quantifies the realistic range of the variability in aerosol optical depth (AOD), its Angstrom exponent, in-situ extinction coefficient and carbon monoxide mixing ratio over horizontal distances of 1-30 km, using measurements from the ARCTAS airborne experiment. The Canada phase in June and July 2008, in which smoke from local forest fires was sampled, likely represents the most heterogeneous of the ambient aerosol environments common over the globe. The relative standard deviation (stdrel) of AOD measured with the 14-channel Ames Airborne Tracking Sunphotometer (AATS-14) has median 19.4% (at 499 nm) among thousands of horizontal 20 km segments. For 6 km segments the analogous median is 9.1%. Another measure of horizontal variability, the autocorrelation (r) of AOD499 across 20 km and 6 km segments is 0.37 and 0.71, respectively. In contrast, the Alaska phase in April 2008, which sampled particles transported from Asia, is presumably among the most homogeneous environments. The median stdrel is 3.0% and r is 0.90, both over 30 km, only slightly different from those for 1 km (stdrel=0.4% and r=1.00). r in the Canada phase is ~0.2 less for in situ extinction coefficient (from a nephelometer and a particle soot absorption photometer) than for the AOD. It is ~0.1 less than for the carbon monoxide mixing ratio. The trends of horizontal variability with distance and aerosol environment are different for the wavelength dependence and the humidity response of light scattering. We discuss challenges in estimating aerosol optical properties, particle size and chemical composition from measurements at a distant location. The statistical parameters thus help interpret existing remote

  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.; 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

  5. 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

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

    SciTech Connect

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

    1993-03-20

    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 mid-latitudes ([approximately]45[degrees]N) and tropical latitudes (12[degrees]S-25[degrees]S). They are compared with in situ frost point hygrometer data provided by balloon experiments from the Laboratoire de Meteorologie Dynamique. At [plus minus]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). 17 refs., 4 figs.

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

    NASA Astrophysics Data System (ADS)

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

    1993-03-01

    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 Atmosphérique. Comparisons were made between these two algorithms and some results are presented at mid-latitudes (~45°N) and tropical latitudes (12°S-25°S). They are compared with in situ frost point hygrometer data provided by balloon experiments from the Laboratoire de Météorologie 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).

  9. Observations of Ozone and Aerosols Over Mexico and Gulf of Mexico During INTEX- B/MILAGRO Field Experiment

    NASA Astrophysics Data System (ADS)

    Butler, C. F.; Browell, E. V.; Hair, J. W.; Fenn, M. A.; Notari, A.; Kooi, S. A.; Ismail, S.; Avery, M. A.; Pierce, R. B.

    2007-12-01

    The NASA Langley Research Center's Differential Absorption Lidar (LaRC/DIAL) system has been used to measure ozone and aerosol distributions in many airborne global tropospheric and stratospheric campaigns since 1980. The tropospheric configuration of this system was flown on the NASA DC-8 during the INTEX-B (Phase-I)/MILAGRO (I/M) field experiment, which was conducted from 24 February to 22 March 2006 over Mexico and the Gulf of Mexico. DIAL remote profile measurements were made from near the surface to above the tropopause along the flight track of the DC-8 with a small data void region of 750 m above and below the aircraft. Aerosol scattering ratios were determined at two wavelengths for a gross estimation of the relative size of the observed particles and measurements of aerosol depolarization were made to distinguish nonspherical aerosols, such as dust and some aerosols in aged fire plumes. In situ measurements of ozone from the FASTOZ instrument on the DC-8 were used to constrain the interpolation of the nadir and zenith ozone lidar measurements, which then provided an estimate of the entire tropospheric ozone profile along the flight track. A first order correction for aerosol attenuation was made to the aerosol profiles by using an assumed extinction-to- backscatter ratio to better characterize the attenuation by thick aerosol layers. The DIAL system was used to determine the large-scale variability and context of air masses being sampled in situ on the DC-8 and to direct the in situ sampling strategy in real time. Plumes from biomass burning in southern Mexico were often observed in the free troposphere over the Gulf of Mexico and over eastern Mexico. The Mexico City (MC) pollution plume was readily apparent with high ozone (>100 ppbv), high aerosol scattering (S>20), and enhanced aerosol depolarization (D>10%). The top of the MC pollution extended to a depth of about 2.5 km AGL. Some observations showed the MC plume spilling out over the mountains to

  10. 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

  11. Initial Operation and Checkout of Stratospheric Aerosol Gas Experiment and Meteor-3M Satellite

    NASA Technical Reports Server (NTRS)

    Habib, Shahid; Makridenko, L.; Chu, W.; Salikhov, R.; Moore, A.; Trepte, C.; Cisewski, M.

    2002-01-01

    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 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 innovative approaches 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 issues

  12. Experiments on aerosol-induced cooling in the nocturnal boundary layer

    NASA Astrophysics Data System (ADS)

    Sreenivas, K.; Singh, D. K.; Vk, P.; Mukund, V.; Subramanian, G.

    2012-12-01

    In the nocturnal boundary layer (NBL), under calm & clear-sky conditions, radiation is the principal mode of heat transfer & it determines the temperature distribution close to the ground. Radiative processes thus influence the surface energy budget, & play a decisive role in many micro-meteorological processes including the formation of radiation-fog & inversion layer. Here, we report hyper-cooling of air layers close to the ground that has a radiative origin. Resulting vertical temperature distribution has an anomalous profile with an elevated minimum few decimetres above the ground (known as Lifted Temperature Minimum; LTM). Even though the first observation of this type of profile dates back to 1930s, its origin has not been explained till recently. We report field experiments to elucidate effects of emissivity and other physical properties of the ground on the LTM profile. Field observations clearly indicate that LTM-profiles are observed as a rule in the lowest meter of the NBL. We also demonstrate that the air-layer near the ground, rather than the ground itself, leads the post sunset cooling. This fact changes the very nature of the sensible heat-flux boundary condition. A laboratory experimental setup has been developed that can reproduce LTM. Lab-experiments demonstrate that the high cooling rates observed in the field experiments arise from the presence of aerosols & the intensity of cooling is proportional to aerosol concentration (Fig-1). We have also captured penetrative convection cells in the field experiments (Fig-2). Results presented here thus help in parameterizing transport processes in the NBL.

  13. 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.

  14. Stratospheric aerosol and gas experiment III (SAGE III) aerosol and trace gas measurements for Earth Observing System (EOS)

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Chu, W. P.; Zawodny, J. M.; Mauldin, L. E.; Mcmaster, L. R.

    1991-01-01

    The SAGE III instrument, the latest in a series of satellite-based instruments employing the self-calibrating solar occultation technique to monitor aerosols and trace gases in the atmosphere, and potential contributions to monitoring global change and other EOS objectives are described. Uses of these data are illustrated with SAGE I and II long-term ozone, aerosol, and water vapor data. The SAGE III instrument will improve the SAM II and SAGE data products with greater overall accuracy, and will provide the ability to extend these measurements over a greater height range. SAGE III will provide long-term self-calibrating global data sets from the midtroposphere to mesosphere, which will contribute greatly to the quantification and understanding of global change.

  15. 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

  16. 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

  17. 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.

  18. 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?

  19. 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

  20. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    Results are presented of a comparison beteen observations of the upper-tropospheric water vapor data obtained from the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument and radiosonde observations for 1987 and radiosonde-based climatologies. Colocated SAGE II-radiosonde measurement pairs are compared individually and in a zonal mean sense. A straight comparison of monthly zonal means between SAGE II and radiosondes for 1987 and Global Atmospheric Statistics (1963-1973) indicates that the clear-sky SAGE II climatology is approximately half the level of clear/cloudy sky of both radiosonde climatologies. Annual zonal means calculated from the set of profile pairs again showed SAGE II to be significantly drier in many altitude bands.

  2. 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.

  3. 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

  4. The Beijing Olympics as a Field Experiment - The Aerosol Footprint of a Megacity

    NASA Astrophysics Data System (ADS)

    Cermak, J.; Knutti, R.

    2009-04-01

    During the 2008 Olympic Summer Games, emission reductions were enforced in and around Beijing to improve the notoriously poor air quality in the city. In this presentation we explore the effect of these measures on the regional aerosol load. To this end, we compare satellite-retrieved aerosol optical thickness of that period with previous years. In addition to absolute changes we explore the 2008 situation in its meteorological context. Using a neural network approach we predict summer 2008 aerosol based on meteorological conditions. Predicted values are contrasted with observations. A statistically significant reduction of aerosol load is found in Beijing that decreases in magnitude and significance with increasing region size. Locally, the aerosol load (log(AOT)) was about 10-15% below the levels expected for the prevailing meteorological situation. The small size of this effect highlights the importance of regional aerosol transport.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Aerosol source attributions and source-receptor relationships across the Northern Hemisphere ---- initial results from HTAP2 model experiments

    NASA Astrophysics Data System (ADS)

    Bian, H.; Chin, M.; Kucsera, T. L.; Torres, O.; Pan, X.

    2014-12-01

    Emissions and long-range transport of air pollution pose major concerns on air quality and climate change. To better assess the impact of intercontinental transport of air pollution on regional and global air quality, ecosystems, and near-term climate change, the UN Task Force on Hemispheric Transport of Air Pollution (HTAP) is organizing a phase II activity (HTAP2) that includes global and regional model experiments and data analysis, focusing on ozone and aerosols. This study presents the initial results of HTAP2 global aerosol modeling experiments. We will (a) evaluate the model results with surface and aircraft measurements, (b) examine the relative contributions of regional emission and extra-regional source on surface PM concentrations and column aerosol optical depth (AOD) over several NH pollution and dust source regions and the Arctic, and (c) quantify the source-receptor relationships in the pollution regions that reflect the sensitivity of regional aerosol amount to the regional and extra-regional emission reductions.

  10. 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.

  11. 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

  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. Laboratory experiments on cluster/aerosol formation by colliding ablation plumes

    NASA Astrophysics Data System (ADS)

    Hirooka, Y.; Tanaka, K. A.; Sato, H.; Ishihara, K.; Sunahara, A.

    2010-08-01

    First-of-a-kind experiments on cluster/aerosol formation by colliding ablation plumes have been conducted, radiating Al, Cu and C with 3ω-YAG laser at power densities between 2~30 J/cm2/pulse. Visible spectroscopy indicates that the excitation light intensities of Cu and Al plumes are not necessarily be doubled in collision, but can rather be weakened due to atomic and molecular reactions. For colliding C plumes, Swan band radiation has been observed, indicative of C2 and/or C2+ formation, and ion mass spectrometry has identified Cn+-clusters, including C+, C2+, C3+, C4+ and C5+. From ICCD camera observations, C plumes generated at power densities above ~15 J/cm2/pulse tend to split into two components with respective velocities, only the slow component of which appears to be interactive to form clusters. Nano structures like CNT have been identified in deposits from colliding C plumes.

  14. 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.

  15. 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/).

  16. 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.

  17. Dimers and organosulfates derived from biogenic oxidation products in aerosols during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) in California 2007 and 2009 (Invited)

    NASA Astrophysics Data System (ADS)

    Glasius, M.; Worton, D. R.; Kristensen, K.; Nguyen, Q.; Surratt, J.; Enggrob, K. L.; Bouvier-Brown, N. C.; Farmer, D.; Docherty, K. S.; Platt, S.; Bilde, M.; Nøjgaard, J. K.; Seinfeld, J.; Jimenez, J. L.; Goldstein, A.

    2010-12-01

    Oxidation products of biogenic volatile organic compounds, such as monoterpenes and isoprene, contribute to biogenic secondary organic aerosol (BSOA). The organosulfate derivatives of these compounds are formed through heterogeneous reactions involving sulphur compounds, with a considerable contribution from anthropogenic sources. Organosulfate derivatives of biogenic oxidation products thus belong to a new group of anthropogenic enhanced biogenic SOA (ABSOA). The Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) during summers of 2007 and 2009 provided an excellent platform at Blodgett Forest, California (a ponderosa pine plantation) for studying ABSOA. Typically, polluted air masses were transported upslope from the California Central Valley during day, while night conditions were influenced by downslope transport of air masses, low local atmospheric mixing and formation of a shallow boundary layer. We collected particle samples (PM2.5) as one nighttime and two daytime samples per day. After extraction of filters in polar organic solvents (i.e. acetonitrile or methanol), organic aerosol constituents were analyzed by HPLC coupled through an electrospray inlet to a quadrupole time-of-flight mass spectrometer (qTOF-MS). Organosulfates and nitrooxy organosulfates derived from oxidation products of α-pinene, β-pinene, limonene and isoprene were identified based on their molecular mass and MS fragmentation patterns. Measurements by High Resolution Time of Flight Aerosol Mass Spectrometry (HR-ToF-AMS) show high mass loadings of nitrate in the night and morning samples with highest levels of the nitrooxy organosulfates with MW 295 and MW 297. This may indicate that elevated levels of nitrate and nitrooxy organosulfates are formed in the same polluted air mass, probably through nitrate radical reactions. Terpenylic acid, diterpenylic acid acetate, and methylbutane tricarboxylic acid were found at concentrations comparable to pinic acid. A dimer of

  18. Heterogeneous ice nucleation on atmospheric aerosols: a review of results from laboratory experiments

    NASA Astrophysics Data System (ADS)

    Hoose, C.; Möhler, O.

    2012-10-01

    A small subset of the atmospheric aerosol population has the ability to induce ice formation at conditions under which ice would not form without them (heterogeneous ice nucleation). While no closed theoretical description of this process and the requirements for good ice nuclei is available, numerous studies have attempted to quantify the ice nucleation ability of different particles empirically in laboratory experiments. In this article, an overview of these results is provided. Ice nucleation "onset" conditions for various mineral dust, soot, biological, organic and ammonium sulfate particles are summarized. Typical temperature-supersaturation regions can be identified for the "onset" of ice nucleation of these different particle types, but the various particle sizes and activated fractions reported in different studies have to be taken into account when comparing results obtained with different methodologies. When intercomparing only data obtained under the same conditions, it is found that dust mineralogy is not a consistent predictor of higher or lower ice nucleation ability. However, the broad majority of studies agrees on a reduction of deposition nucleation by various coatings on mineral dust. The ice nucleation active surface site (INAS) density is discussed as a simple and empirical normalized measure for ice nucleation activity. For most immersion and condensation freezing measurements on mineral dust, estimates of the temperature-dependent INAS density agree within about two orders of magnitude. For deposition nucleation on dust, the spread is significantly larger, but a general trend of increasing INAS densities with increasing supersaturation is found. For soot, the presently available results are divergent. Estimated average INAS densities are high for ice-nucleation active bacteria at high subzero temperatures. At the same time, it is shown that INAS densities of some other biological aerosols, like certain pollen grains, fungal spores and diatoms

  19. Heterogeneous ice nucleation on atmospheric aerosols: a review of results from laboratory experiments

    NASA Astrophysics Data System (ADS)

    Hoose, C.; Möhler, O.

    2012-05-01

    A small subset of the atmospheric aerosol population has the ability to induce ice formation at conditions under which ice would not form without them (heterogeneous ice nucleation). While no closed theoretical description of this process and the requirements for good ice nuclei is available, numerous studies have attempted to quantify the ice nucleation ability of different particles empirically in laboratory experiments. In this article, an overview of these results is provided. Ice nucleation onset conditions for various mineral dust, soot, biological, organic and ammonium sulphate particles are summarized. Typical temperature-supersaturation regions can be identified for the onset of ice nucleation of these different particle types, but the various particle sizes and activated fractions reported in different studies have to be taken into account when comparing results obtained with different methodologies. When intercomparing only data obtained under the same conditions, it is found that dust mineralogy is not a consistent predictor of higher or lower ice nucleation ability. However, the broad majority of studies agrees on a reduction of deposition nucleation by various coatings on mineral dust. The ice nucleation active surface site (INAS) density is discussed as a normalized measure for ice nucleation activity. For most immersion and condensation freezing measurements on mineral dust, estimates of the temperature-dependent INAS density agree within about two orders of magnitude. For deposition nucleation on dust, the spread is significantly larger, but a general trend of increasing INAS densities with increasing supersaturation is found. For soot, the presently available results are divergent. Estimated average INAS densities are high for ice-nucleation active bacteria at high subzero temperatures. At the same time, it is shown that some other biological aerosols, like certain pollen grains and fungal spores, are not intrinsically better ice nuclei than dust

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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

  8. Dust Aerosol Optical Properties Retrieval and Radiative Forcing over Northwestern China during 2008 China-US Joint Field Experiment

    NASA Astrophysics Data System (ADS)

    Ge, J.; Su, J.; Ackerman, T. P.; Fu, Q.; Huang, J.; Shi, J.

    2009-12-01

    The Atmosphere Radiation Measurements (ARM) Program’s Ancillary Facility (AAF/SMART-COMMIT) was deployed to Zhangye (39.082° N, 100.276° E), which is located in a semi-desert area of Northwest China, during the period of late April to mid June in 2008. We selected 11 cases to retrieve dust aerosol optical depth (AOD), Angstrom exponent, size distribution, single-scattering albedo (SSA) and asymmetry parameter (ASY) from Multi-filter Rotating Shadowband Radiometer (MFRSR) measurements. These cases are dominated by large particles with Angstrom exponent values ranging from 0.34 to 0.93. The values of AOD at 0.67 µm range from 0.074 to 0.249. The mean SSA value increases with wavelength from 0.76±0.02 at 0.415 µm to 0.86±0.01 at 0.867 µm, while the mean ASY value decreases from 0.74±0.04 to 0.70±0.02. Before estimating dust aerosol direct radiative forcing, a radiative closure experiment was performed to verify that the retrieved aerosol optical properties and other input parameters to the radiative transfer model appropriately represent atmospheric conditions. The daytime-averaged differences between model simulations and ground observations are -8.5, -2.9, and -2.1 Wm-2 for the total, diffuse, and direct normal fluxes, respectively. The mean difference in the instantaneous reflected solar fluxes at the top of atmosphere (TOA) between the model and CERES observations is 8.0 Wm-2. The solar aerosol direct radiative forcing (ARF), averaged over a 24-hour period, at the surface is-22.4±8.9 Wm-2, while the TOA ARF is small and has an average value of only 0.52±1.69 Wm-2. The daily-average surface aerosol radiative forcing efficiency (ARFE) at 0.5 µm is -95.1±10.3 Wm-2τ-1. Our results illustrate that the primary role of dust aerosol is to alter the distribution of solar radiation within the climate system, rather than reflecting solar energy to space. We assess the satellite aerosol optical depth products from MISR and MODIS observations by comparing them

  9. 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.

  10. 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

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

    NASA Astrophysics Data System (ADS)

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

    1993-03-01

    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, we 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. We 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.

  12. 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.

  13. 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.

  14. 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.

  15. Optical properties of aerosols during APEX and ACE-Asia experiments

    NASA Astrophysics Data System (ADS)

    Sano, Itaru; Mukai, Sonoyo; Okada, Yasuhiko; Holben, Brent N.; Ohta, Sachio; Takamura, Tamio

    2003-12-01

    Sun/sky photometry and polarimetry of atmospheric light have been undertaken by multispectral photometers (CE-318-1 and -2, Cimel Electronique, France) and a polarimeter (PSR-1000, Opto Research, Japan) over Amami, Noto, and Shirahama, Japan, during APEX-E1, -E2, and ACE-Asia field campaigns. Radiometers provide us with the optical thickness of aerosols and Ångström exponent. Other aerosol characteristics, e.g., size distribution, refractive index, etc., are retrieved based on each inversion method corresponding each equipment. The former takes a standard AERONET processing, and the latter is according to our own procedure to analyze the polarimetry with PSR-1000. After several aerosol parameters are derived, the HYSPLIT4 backward trajectory analysis is adopted to search the origin of aerosols. It is shown from these ground measurements that aerosol optical thickness, Ångström exponent, and refractive index are classified into two typical categories as a background type detected in winter, and a soil dust type appeared in Asian dust events in spring. Further, it is found that the obtained size distribution of Asian dust indicates the dominance of large particles.

  16. Clinical experience with technetium-99m DTPA aerosol with perfusion scintigraphy in suspected pulmonary embolism

    SciTech Connect

    Selby, J.B.; Gardner, J.J.

    1987-01-01

    To evaluate the clinical value of radioaerosol imaging, 156 patients with suspected pulmonary embolism (PE) were studied. In 25 patients, a preperfusion xenon-133 (Xe-133) study was compared with a postperfusion study using Tc-99m DTPA aerosol. It was found that they were of equal value most of the time (56%), but that the aerosol study was more often helpful. Because of this, and the technical ease of using six standard views with radioaerosol, the series was completed using perfusion scintigraphy followed by radioaerosol images. In 19 patients the perfusion scintigraphy with Tc-99 macroaggregated albumin (Tc-99m MAA) was normal or nearly normal and no aerosol study was required. Tc-99m DTPA aerosol images were satisfactory when the count rate was at least twice and preferably three times that of the previous perfusion study. There were 17 studies (11%) classified as intermediate. There were 26 patients classified as high probability for PE, and angiographic or autopsy correlation was available in 14. All of the 14 proved to have PE. In the 113 patients classified as low probability, there were ten with angiographic or autopsy correlation. In the ten, there was one patient with a small pulmonary embolus found at autopsy. Clinical follow-up for over two months confirmed the absence of PE in the remainder of this group. Aerosol studies have proven technically easier to perform and a satisfactory substitute for xenon imaging in suspected PE.

  17. 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

  18. 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

  19. 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

  20. 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

  1. Current and future advances in optical multiangle remote sensing of aerosols and clouds based on Terra/MISR experience

    NASA Astrophysics Data System (ADS)

    Diner, David J.; Davies, Roger; Kahn, Ralph; Martonchik, John; Gaitley, Barbara; Davis, Ab

    2006-12-01

    Through acquisition of well-calibrated near-nadir and oblique-angle imagery (0° - 70° zenith angles) at moderately high spatial resolution (275 m - 1.1 km), the Multi-angle Imaging SpectroRadiometer (MISR) experiment aboard NASA's Terra satellite has taken atmospheric remote sensing in new directions. Retrieval algorithms that were largely conceptual prior to Terra launch in 1999 have led to publicly available aerosol and cloud products with direct application to global climate and particulate air quality research. Automated algorithms making use of stereoscopic parallax, time lapse among the nine angular views, and the variation in radiance with view angle, scattering angle, and wavelength (446-866 nm) make possible unique data sets including geometric cloud and aerosol plume heights derived independently of emissivity or temperature assumptions; height-resolved cloud-tracked winds; and aerosol optical depth and particle type over a wide variety of surfaces including bright desert source regions. To illustrate these capabilities, examples of regional and global MISR data products, quantitative evaluations of product accuracies based on comparisons with independent data sources, and time series showing seasonal and interannual variations are presented here. Future sensor improvements aimed at building upon MISR heritage, including expanding the spectral coverage to ultraviolet and shortwave infrared wavelengths, adding polarization channels, and widening the sensor swath, are also discussed.

  2. One Year of Doppler Lidar Observations Characterizing Boundary Layer Wind, Turbulence, and Aerosol Structure During the Indianapolis Flux Experiment

    NASA Astrophysics Data System (ADS)

    Hardesty, R. M.; Brewer, A.; Shepson, P. B.; Cambaliza, M. O. L.; Salmon, O. E.; Heimburger, A. M. F.; Davis, K. J.; Lauvaux, T.; McGowan, L. E.; Miles, N. L.; Richardson, S.; Sarmiento, D. P.; Karion, A.; Sweeney, C.; Iraci, L. T.; Hillyard, P. W.; Podolske, J. R.; Gurney, K. R.; Razlivanov, I. N.; Song, Y.; Turnbull, J. C.; Whetstone, J. R.; Possolo, A.; Prasad, K.

    2014-12-01

    The Indianapolis Flux Experiment (INFLUX) is aimed at improving methods for estimation of greenhouse gas emissions at urban scales. INFLUX observational components include several-times-per-month aircraft measurements of gas concentrations and meteorological parameters, as well as a number of towers observing CO2, CH4, and CO and a single continuously operating Doppler lidar to estimate wind, turbulence and aerosol structure in the boundary layer. The observations are used to develop top-down emissions estimates from the aircraft measurements and as input to inversion models. The Doppler lidar provides information on boundary layer structure for both the aircraft and inversion studies. A commercial Doppler lidar characterized by low pulse energy and high pulse repetition rate has operated for well over a year at a site NE of downtown Indianapolis. The lidar produces profiles of horizontal wind speed, vertical velocity variance, and aerosol structure two to three times per hour. These data are then used to investigate boundary layer mixing and thickness and horizontal transport as inputs for the flux calculations. During its one year deployment the lidar generally operated reliably with few outages. Comparisons with aircraft spirals over the site and with the NOAA High Resolution research Doppler lidar deployed to Indianapolis for one month during May, 2014, were used to assess the performance of the INFLUX lidar. Measurements agreed quite well when aerosol loading was sufficient for lidar observations throughout the boundary layer. However, low aerosol loading during some periods limited the range of the lidar and precluded characterization of the full boundary layer. We present an overall assessment of the commercial Doppler lidar for providing the needed information on boundary layer structure for emission estimations, and show variability of the boundary layer observations over diurnal, seasonal, and annual cycles. Recommendations on system design changes to

  3. Aerosol and Cloud Properties during the Cloud Cheju ABC Plume -Asian Monsoon Experiment (CAPMEX) 2008: Linking between Ground-based and UAV Measurements

    NASA Astrophysics Data System (ADS)

    Kim, S.; Yoon, S.; Venkata Ramana, M.; Ramanathan, V.; Nguyen, H.; Park, S.; Kim, M.

    2009-12-01

    Cheju Atmospheric Brown Cloud (ABC) Plume-Monsoon Experiment (CAPMEX), comprehsensive ground-based measurements and a series of data-gathering flights by specially equipped autonomous unmanned aerial vehicles (AUAVs) for aerosol and cloud, had conducted at Jeju (formerly, Cheju), South Korea during August-September 2008, to improve our understanding of how the reduction of anthropogenic emissions in China (so-called “great shutdown” ) during and after the Summer Beijing Olympic Games 2008 effcts on the air quliaty and radiation budgets and how atmospheric brown clouds (ABCs) influences solar radiation budget off Asian continent. Large numbers of in-situ and remote sensing instruments at the Gosan ABC observatory and miniaturized instruments on the aircraft measure a range of properties such as the quantity of soot, size-segregated aerosol particle numbers, total particle numbers, size-segregated cloud droplet numbers (only AUAV), aerosol scattering properties (only ground), aerosol vertical distribution, column-integrated aerosol properties, and meteorological variables. By integrating ground-level and high-elevation AUAV measurements with NASA-satellite observations (e.g., MODIS, CALIPSO), we investigate the long range transport of aerosols, the impact of ABCs on clouds, and the role of biogenic and anthropogenic aerosols on cloud condensation nuclei (CCN). In this talk, we will present the results from CAPMEX focusing on: (1) the characteristics of aerosol optical, physical and chemical properties at Gosan observatory, (2) aerosol solar heating calculated from the ground-based micro-pulse lidar and AERONET sun/sky radiometer synergy, and comparison with direct measurements from UAV, and (3) aerosol-cloud interactions in conjunction with measurements by satellites and Gosan observatory.

  4. Measurements of aerosol distributions and properties from Airborne High Spectral Resolution Lidar and DRAGON during the DISCOVER-AQ California Experiment (Invited)

    NASA Astrophysics Data System (ADS)

    Ferrare, R. A.; Burton, S. P.; Scarino, A. J.; Hostetler, C. A.; Hair, J. W.; Rogers, R. R.; Mueller, D.; Chemyakin, E.; Cook, A. L.; Harper, D. B.; Hare, R.; Holben, B. N.; Schafer, J.; Anderson, B. E.; Sawamura, P.

    2011-12-01

    The new NASA Langley Research Center airborne High Spectral Resolution Lidar-2 (HSRL-2) was deployed from the NASA Langley King Air aircraft for the DISCOVER-AQ (Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality) and DRAGON experiments that occurred over the San Joaquin Valley during January and February, 2013. The HSRL-2, which is the world's first airborne multiwavelength HSRL, measures aerosol extinction at 355 and 532 nm via the HSRL technique, as well as aerosol backscatter and depolarization at 355, 532, and 1064 nm. Additional HSRL-2 data products include aerosol type, mixed layer depth, and range-resolved aerosol microphysical parameters (e.g., effective radius, index of refraction, single scatter albedo, and concentration). During this mission, the King Air flights and HSRL-2 measurements were acquired over the DRAGON network and long-term AERONET sites and were closely coordinated with flights of the NASA P-3 aircraft that carried a suite of in situ aerosol instruments. In this presentation, we discuss how the HSRL-2 and DRAGON observations have been used to examine aerosol optical and microphysical properties as well as spatial and temporal variability. On some days, both HSRL-2 and DRAGON measurements indicated that coarse mode dust contributed a significant fraction of the aerosol optical thickness (AOT); in these cases, HSRL-2 measurements indicated that this depolarizing layer was located at the top of the boundary layer. We discuss differences in the aerosol properties between two episodes of high surface PM2.5 concentrations as revealed by the HSRL-2 and DRAGON measurements. Both the HSRL-2 and DRAGON measurements reveal considerable day-to-day spatial variability in the aerosol distributions across the valley. The HSRL-2 measurements also show variability in the daily evolution of the vertical distribution of aerosols.

  5. Measurements of aerosol distributions and properties from Airborne High Spectral Resolution Lidar and DRAGON during the DISCOVER-AQ California Experiment (Invited)

    NASA Astrophysics Data System (ADS)

    Ferrare, R. A.; Burton, S. P.; Scarino, A. J.; Hostetler, C. A.; Hair, J. W.; Rogers, R. R.; Mueller, D.; Chemyakin, E.; Cook, A. L.; Harper, D. B.; Hare, R.; Holben, B. N.; Schafer, J.; Anderson, B. E.; Sawamura, P.

    2013-12-01

    The new NASA Langley Research Center airborne High Spectral Resolution Lidar-2 (HSRL-2) was deployed from the NASA Langley King Air aircraft for the DISCOVER-AQ (Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality) and DRAGON experiments that occurred over the San Joaquin Valley during January and February, 2013. The HSRL-2, which is the world's first airborne multiwavelength HSRL, measures aerosol extinction at 355 and 532 nm via the HSRL technique, as well as aerosol backscatter and depolarization at 355, 532, and 1064 nm. Additional HSRL-2 data products include aerosol type, mixed layer depth, and range-resolved aerosol microphysical parameters (e.g., effective radius, index of refraction, single scatter albedo, and concentration). During this mission, the King Air flights and HSRL-2 measurements were acquired over the DRAGON network and long-term AERONET sites and were closely coordinated with flights of the NASA P-3 aircraft that carried a suite of in situ aerosol instruments. In this presentation, we discuss how the HSRL-2 and DRAGON observations have been used to examine aerosol optical and microphysical properties as well as spatial and temporal variability. On some days, both HSRL-2 and DRAGON measurements indicated that coarse mode dust contributed a significant fraction of the aerosol optical thickness (AOT); in these cases, HSRL-2 measurements indicated that this depolarizing layer was located at the top of the boundary layer. We discuss differences in the aerosol properties between two episodes of high surface PM2.5 concentrations as revealed by the HSRL-2 and DRAGON measurements. Both the HSRL-2 and DRAGON measurements reveal considerable day-to-day spatial variability in the aerosol distributions across the valley. The HSRL-2 measurements also show variability in the daily evolution of the vertical distribution of aerosols.

  6. 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

  7. Insights into aerosol formation chemistry from comprehensive gas-phase precursor measurement in the TRAPOZ chamber experiments; an overview

    NASA Astrophysics Data System (ADS)

    Carr, Timo; Wyche, Kevin; Monks, Paul S.; Camredon, Marie; Alam, Mohammed S.; Bloss, William J.; Rickard, Andrew R.

    2010-05-01

    Aerosols have a profound affect on the environment on local, regional and even global levels, with impacts including adverse health effects, (Alfarra, Paulsen et al. 2006) visibility reduction, cloud formation, direct radiative forcing (Charlson, Schwartz et al. 1992) and an important role in influencing the climate due to their contribution to important atmospheric processes (Baltensperger, Kalberer et al. 2005; Alfarra, Paulsen et al. 2006). The Total Radical Production from the OZonolysis of alkenes (TRAPOZ) project was used to study the gas phase and radical chemistry along with secondary organic aerosol (SOA) formation for a number of different alkenes and terpenes. In order to better the scientific knowledge regarding the oxidation mechanisms of terpene and alkene species along with radical and SOA formation, the experiments were conducted under varying conditions controlled and monitored by the EUropean PHOto REactor (EUPHORE) simulation chamber in Valencia, Spain. A vast number of instruments enabled a detailed examination of the chemistry within oxidation of each precursor. However the work here will focus on the results obtained from the University of Leicester Chemical Ionisation Reaction Time-of-Flight Mass Spectrometer (CIR-TOF-MS). With regard to the gas phase chemistry an analysis of the degradation of the precursor Volatile Organic Compounds (VOCs) and evolution of certain gas phase species in each experiment has been presented and discussed.

  8. 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.

  9. 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.

  10. Carbonaceous aerosol characteristics over a Pinus taeda plantation: Results from the CELTIC experiment

    NASA Astrophysics Data System (ADS)

    Geron, Chris

    2011-01-01

    Carbonaceous particles smaller than 2.5 μm aerodynamic diameter (PM 2.5) were collected in July, 2003 over a Loblolly Pine plantation at Duke Forest, NC during the Chemical Emission, Loss, Transformation and Interactions within Canopies (CELTIC) field study. Organic (OC) and elemental (EC) carbon in PM 2.5 ranged from 1.4-6.3 and 0.08-0.41 μg C m -3, respectively, and concentrations measured above and below the pine canopy were in good agreement. Ambient OC was lower (<3 μg C m -3) during cooler periods (daytime maximum temperatures < 28 °C) and for periods following precipitation events, and was higher (>3 μg C m -3) during warm humid periods. Radiocarbon analysis indicates that on average 83% (range 78-91%) of the PM 2.5 carbon was derived from contemporary (biogenic VOC and biomass burning) sources. This is higher than previous estimates from urban and suburban sites, and in good agreement with recently published data from other rural sites throughout the U.S. The estimates of contemporary PM 2.5 carbon may represent a lower limit for this site since the sampler was located above the center of a 30 meter diameter plot fumigated with 200 ppm CO 2 derived from fossil carbon sources. However, this effect is likely to be negligible. The regression relationship between OC/EC ratios and percent biogenic carbon in aerosol is very similar to those observed in recent summertime data from Tennessee and Florida. However, our values for both OC/EC and percent biogenic carbon are higher than those observed in the latter studies, likely due to the more rural character of the site. Simple box model estimates indicate that biogenic VOC (BVOC) emissions measured at the site provide sufficient reactive carbon sources to account for the observed levels of aerosol biogenic carbon. The magnitude and temporal pattern in the box model secondary organic aerosol estimates correlate well with the ambient aerosol carbon measurements. The model estimates of the relative contribution

  11. 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.

  12. 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

  13. 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.

  14. Modeling the organic aerosol fraction within the Mexico City basin during the MILAGRO field experiment

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Jimenez, J. L.; Madronich, S.; Aiken, A. C.; Bessagnet, B.; Fast, J.; Lamarque, J. F.; Onasch, T. B.; Roux, G.; Ulbrich, I. M.

    2009-04-01

    The meso-scale chemistry-transport model CHIMERE is used to asses our understanding of major sources and formation processes leading to a fairly abundant fraction of organic aerosols (OA, including primary OA (POA) and secondary OA (SOA)) observed in Mexico City during the MILAGRO field project (March 2006). Chemical analysis of submicron aerosols from aerosol mass spectrometers (AMS) indicate that carbonaceous particles found in the Mexico City basin have a large fraction of oxygenated organic species (OOA) which show strong correspondence with SOA, and that their production actively continues downwind of the city. The SOA formation is modeled according to the first-generation oxidation of anthropogenic (i.e. aromatics, alkanes) and biogenic (i.e. monoterpenes and isoprene) precursors and their partitioning into both organic and aqueous phases. The near-surface model evaluation shows that predicted OA correlates reasonably well with measurements during the campaign, however it remains a factor of 2-3 lower than the measured TOA. One of the reasons for this large gap is the inability of the model to simulate TOA peaks associated with the biomass burning events suggesting that near-city fires are not correctly represented in the emissions inventory (most likely too small to be detected by satellites). Fairly good agreement is found between observed and predicted POA within the city indicating that primary emissions are reasonable. Consistent with previous studies in Mexico City, large discrepancies are found for SOA species characterized by a factor of 5-10 model underestimate. When only anthropogenic SOA precursors were considered, the model was able to reproduce the sharp increase in SOA concentrations during the late morning at both urban and near-urban locations. However, predicted SOA concentrations were unrealistically low when photochemistry was not active, especially overnight. These discrepancies were not significantly reduced when greatly enhanced

  15. A comparison of Solar Mesosphere Explorer and Stratosphere Aerosol and Gas Experiment II ozone densities near the stratopause

    NASA Technical Reports Server (NTRS)

    Rusch, D. W.; Clancy, R. T.; Mccormick, M. P.; Zawodny, J. M.

    1990-01-01

    Ozone measurements made by the SME UV Spectrometer and the Stratosphere Aerosol and Gas Experiment II (SAGE II) spectometer are compared at 1.0 mbar for the time period from October 1984 to December 1986, using a model of the diurnal variation of ozone to correct for the difference in local times of the two measurements. The absolute values of the ozone mixing ratio measured by the two spectrometers were found to agree to better than 5 percent, with no significant divergence between the instruments. It is concluded that, since the SAGE II data are not dependent on the absolute calibration of the instrument, these data can be used as time-dependent 'ground truth' measurements for comparisons with other instruments.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    Results are presented of water vapor observations in the troposphere and stratosphere performed by the Stratospheric Aerosol and Gas Experiment II solar occultation instrument, and the analysis procedure, the instrument errors, and data characteristics are discussed. The results are compared with correlative in situ measurements and other satellite data. The features of the data set collected between 1985 and 1989 include an increase in middle- and upper-tropospheric water vapor during northern hemisphere summer and autumn; minimum water vapor values of 2.5-3 ppmv in the tropical lower stratosphere; 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.

  17. 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.

  18. Ground based characterization of biomass burning aerosols during the South American Biomass Burning Analysis (SAMBBA) field experiment in Brazil during Sept - Oct 2012

    NASA Astrophysics Data System (ADS)

    Artaxo, Paulo; Ferreira de Brito, Joel; Varanda Rizzo, Luciana; Johnson, Ben; Haywood, Jim; Longo, Karla; Freitas, Saulo; Coe, Hugh

    2013-04-01

    Biomass burning is one of the major drivers for atmospheric composition in the Southern hemisphere. In Amazonia, deforestation rates have been steadily decreasing, from 27,000 Km² in 2004 to about 5,000 Km² in 2011. This large reduction (by factor 5) was not followed by similar reduction in aerosol loading in the atmosphere due to the increase in agricultural fires. AERONET measurements from 5 sites show a large year-to year variability due to climatic and socio-economic issues. Besides this strong reduction in deforestation rate, biomass burning emissions in Amazonia increases concentrations of aerosol particles, CO, ozone and other species, and also change the surface radiation balance in a significant way. To complement the long term biomass burning measurements in Amazonia, it was organized in 2012 the intensive campaign of the South American Biomass Burning Analysis (SAMBBA) experiment with an airborne and a ground based components. A sampling site was set up at Porto Velho, with measurements of aerosol size distribution, optical properties such as absorption and scattering at several wavelengths, organic aerosol characterization with an ACSM - Aerosol Chemical Speciation Monitor. CO, CO2 and O3 were also measured to characterize combustion efficiency and photochemical processes. Filters for trace elements measured by XRF and for OC/EC determined using a Sunset instrument were also collected. An AERONET CIMEL sunphotometer was operated in parallel with a multifilter radiometer (MFR). A large data set was collected from August to October 2012. PM2.5 aerosol concentrations up to 250 ug/m3 were measured, with up to 20 ug/m3 of black carbon. Ozone went up to 60 ppb at mid-day in August. At night time ozone was consumed completely most of the time. ACSM shows that more than 85% of the aerosol mass was organic with a clear diurnal pattern. The organic aerosol volatility was very variable depending on the air mass sampled over Porto Velho. Aerosol optical depth at

  19. 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.

  20. Nocturnal Boundary Layer Measurements during the Amazonian Aerosol Characterization Experiment (AMAZE)

    NASA Astrophysics Data System (ADS)

    Tota, J.; Fisch, G.; Santos, R.; Silva Dias, M.

    2009-05-01

    To characterize the Nocturnal Boundary Layer (NBL) hourly profiles of wind, pressure, temperature, humidity and 5 sizes particles concentration, were made by using tethered balloon at INPA tropical Amazon rainforest Reserve (Cuieiras) 100 km northwest from Manaus city. The measurements were made during the wet season March/2008. The NBL height was 100 to 150m, with a very well mixed layer close to surface associate with temperature inversion. The wind profiles shows a very clear low level in two nights, about 500 to 900 m, and, in general, all nights show an stable and cooler air layer close the surface uncoupled with outer residual boundary layer above. At the site a very clear drainage flow from north quadrant down slope eastward quadrant during very the stable cases. This findings is correlates with particles profiles where was commonly trapped by stable layer presenting high concentrations, for all 5 sizes measured, close to the surface at vegetation level and just above it. All nights presents high humidity with fog formation in three cases, associates with temperature below the 23C. The wind speed were very low about 0.5 to calm, in generally associate with drainage flow down hill. The NBL dynamics is a discussion issue associate to the aerosol nocturnal mixing in complex terrain with tall vegetation, the currently AMAZE site case.

  1. Nocturnal Boundary Layer Measurements during the Amazonian Aerosol Characterization Experiment (amaze)

    NASA Astrophysics Data System (ADS)

    Tota, J.; Santos, R.; Fisch, G.; Querino, C.; Silva Dias, M.; Artaxo, P.; Guenther, A.; Martin, S.; Manzi, A.

    2008-12-01

    To characterize the Nocturnal Boundary Layer (NBL) hourly profiles of wind, pressure, temperature, humidity and 5 sizes particles concentration, were made by using tethered balloon at INPA tropical Amazon rainforest Reserve (Cuieiras) 100 km northwest from Manaus city. The measurements were made during the wet season March/2008. The NBL height was 100 to 150m, with a very well mixed layer close to surface associate with temperature inversion. The wind profiles shows a very clear low level in two nights, about 500 to 900 m, and, in general, all nights show an stable and cooler air layer close the surface uncoupled with outer residual boundary layer above. At the site a very clear drainage flow from north quadrant down slope eastward quadrant during very the stable cases. This findings is correlates with particles profiles where was commonly trapped by stable layer presenting high concentrations, for all 5 sizes measured, close to the surface at vegetation level and just above it. All nights presents high humidity with fog formation in three cases, associates with temperature below the 23°C. The wind speed were very low about 0.5 to calm, in generally associate with drainage flow down hill. The NBL dynamics is a discussion issue associate to the aerosol nocturnal mixing in complex terrain with tall vegetation, the currently AMAZE site case.

  2. 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.

  3. Influence of Aerosols on the Shortwave Cloud Radiative Forcing from North Pacific Oceanic Clouds: Results from the Cloud Indirect Forcing Experiment (CIFEX)

    NASA Technical Reports Server (NTRS)

    Wilcox, Eric M.; Roberts, Greg; Ramanathan, V.

    2007-01-01

    Aerosols over the Northeastern Pacific Ocean enhance the cloud drop number concentration and reduce the drop size for marine stratocumulus and cumulus clouds. These microphysical effects result in brighter clouds, as evidenced by a combination of aircraft and satellite observations. In-situ measurements from the Cloud Indirect Forcing Experiment (CIFEX) indicate that the mean cloud drop number concentration in low clouds over the polluted marine boundary layer is greater by 53 cm(sup -3) compared to clean clouds, and the mean cloud drop effective radius is smaller by 4 micrometers. We link these in-situ measurements of cloud modification by aerosols, for the first time, with collocated satellite broadband radiative flux observations from the Clouds and the Earth s Radiant Energy System to show that these microphysical effects of aerosols enhance the top-of-atmosphere cooling by -.9.9 plus or minus 4.3 W m(sup -2) for overcast conditions.

  4. The Influence of Aerosols on the Shortwave Cloud Radiative Forcing from North Pacific Oceanic Clouds: Results from the Cloud Indirect Forcing Experiment (CIFEX)

    NASA Technical Reports Server (NTRS)

    Wilcox, Eric M.; Roberts, Greg; Ramanathan, V.

    2006-01-01

    Aerosols over the Northeastern Pacific Ocean enhance the cloud drop number concentration and reduce the drop size for marine stratocumulus and cumulus clouds. These microphysical effects result in brighter clouds, as evidenced by a combination of aircraft and satellite observations. In-situ measurements from the Cloud Indirect Forcing Experiment (CIFEX) indicate that the mean cloud drop number concentration in low clouds over the polluted marine boundary layer is greater by 53/cu cm compared to clean clouds, and the mean cloud drop effective radius is smaller by 4 microns. We link these in-situ measurements of cloud modification by aerosols, for the first time, with collocated satellite broadband radiative flux observations from the Clouds and the Earth's Radiant Energy System (CERES) to show that these microphysical effects of aerosols enhance the top-of-atmosphere cooling by -9.9+/-4.3 W/sq m for overcast conditions.

  5. Column-integrated aerosol optical properties from ground-based spectroradiometer measurements at Barrax (Spain) during the Digital Airborne Imaging Spectrometer Experiment (DAISEX) campaigns

    NASA Astrophysics Data System (ADS)

    Pedrós, Roberto; Martinez-Lozano, Jose A.; Utrillas, Maria P.; Gómez-Amo, José L.; Tena, Fernando

    2003-09-01

    The Digital Airborne Imaging Spectrometer Experiment (DAISEX) was carried out for the European Space Agency (ESA) in order to develop the potential of spaceborne imaging spectroscopy for a range of different scientific applications. DAISEX involved simultaneous data acquisitions using different airborne imaging spectrometers over test sites in southeast Spain (Barrax) and the Upper Rhine valley (Colmar, France, and Hartheim, Germany). This paper presents the results corresponding to the column-integrated aerosol optical properties from ground-based spectroradiometer measurements over the Barrax area during the DAISEX campaign days in the years 1998, 1999, and 2000. The instruments used for spectral irradiance measurements were two Licor 1800 and one Optronic OL-754 spectroradiometers. The analysis of the spectral aerosol optical depth in the visible range shows in all cases the predominance of the coarse-particle mode over the fine-particle mode. The analysis of the back trajectories of the air masses indicates a predominance of marine-type aerosols in the lower atmospheric layers in all cases. Overall, the results obtained show that during the DAISEX there was a combination of maritime aerosols with smaller continental aerosols.

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Characterization of PM2.5 aerosols dominated by local pollution and Asian dust observed at an urban site in Korea during aerosol characterization experiments (ACE)--Asia Project.

    PubMed

    Park, Seung Shik; Kim, Young J; Cho, Sung Yong; Kim, Seung Jai

    2007-04-01

    Daily fine particulate matter (PM2.5) samples were collected at Gwangju, Korea, during the Aerosol Characterization Experiments (ACE)-Asia Project to determine the chemical properties of PM2.5 originating from local pollution and Asian dust (AD) storms. During the study period, two significant events occurred on April 10-13 and 24-25, 2001, and a minor event occurred on April 19, 2001. Based on air mass transport pathways identified by back-trajectory calculation, the PM2.5 dataset was classified into three types of aerosol populations: local pollution and two AD aerosol types. The two AD types were transported along different pathways. One originated from Gobi desert area in Mongolia, passing through Hunshandake desert in Northern Inner Mongolia, urban and polluted regions of China (AD1), and the other originated in sandy deserts located in the Northeast Inner Mongolia Plateau and then flowed southward through the Korean peninsula (AD2). During the AD2 event, a smoke plume that originated in North Korea was transported to our study site. Mass balance closures show that crustal materials were the most significant species during both AD events, contributing -48% to the PM2.5 mass; sulfate aerosols (19.1%) and organic matter (OM; 24.6%) were the second greatest contributors during the AD1 and AD2 periods, respectively, indicating that aerosol properties were dependent on the transport pathway. The sulfate concentration constituted only 6.4% (4.5 microg/m3) of the AD2 PM2.5 mass. OM was the major chemical species in the local pollution-dominated PM2.5 aerosols, accounting for 28.7% of the measured PM2.5 mass, followed by sulfate (21.4%), nitrate (15%), ammonium (12.8%), elemental carbon (8.9%), and crustal material (6.5%). Together with substantial enhancement of the crustal elements (Mg, Al, K, Ca, Sc, Ti, Mn, Fe, Sr, Zr, Ba, and Ce), higher concentrations of pollution elements (S, V, Ni, Zn, As, Cd, and Pb) were observed during AD1 and AD2 than during the local

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  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. 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

  19. 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...

  20. 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.

  1. 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

  2. A fine fraction of soil used as an aerosol analogue during the DUNE experiment: sequential solubility in water, decreasing pH step-by-step

    NASA Astrophysics Data System (ADS)

    Aghnatios, C.; Losno, R.; Dulac, F.

    2014-09-01

    A soil sample collected in a desert aerosol source area near Douz (southern Tunisia) was dry-sieved at 20 μm in order to extract the fraction similar to a wind-generated aerosol, and was used to seed mesocosms during the DUNE experiment (a DUst experiment in a low Nutrient, low chlorophyll Ecosystem). In this work, said "aerosol-like" fine dust was sequentially leached by short contacts with water at initial pHs, decreasing from seven to one, representing various wet environmental conditions. For each step, the solubility of a given element is calculated as the amount of its dissolved fraction, relative to its total amount. The evolution of this fractional solubility from the highest to lowest pHs provides information on the chemical strength needed to solubilise a given element and its lability. The behaviour of the elemental solubility was sorted into two groups: (1) Ca, Sr, Ba, Mn, and P, with a solubility between 23% and 70%, and a maximum sequential solubility at pH 3; (2) Al and Fe, with a solubility of less than 2% and the highest release at pH 1. Similar solubility patterns in group 1 for Ca, P, and Mn suggest a possible association of the elements in the same minerals, most probably carbonates.

  3. 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.

  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. 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

  6. A~fine fraction of soil used as an aerosol analogue during the DUNE experiment: sequential solubility in water with step-by-step decreasing pH

    NASA Astrophysics Data System (ADS)

    Aghnatios, C.; Losno, R.; Dulac, F.

    2014-02-01

    A soil sample collected in a desert aerosol source area near Douz (South Tunisia) was sieved at 20 μm in order to extract the fraction similar to an aerosol generated by wind and used to seed mesocosms during the DUNE experiment. In the present work, this "aerosol-like" fine dust was sequentially leached by short contacts with water at pHs decreasing from 7 to 1. These pHs are representative of various environmental wet conditions, the lowest of which could be reached during cloud conditions. The evolution of the solubility from the highest to the lowest pHs provides information on the necessary strength for the solubilisation of a given element and its lability. The behaviour of the elemental fractional solubility is sorted into two groups: (i) Ca, Sr, Ba, Mn, P constitute group 1, with a solubility between 23% and 70% and with a maximum solubility at pH 3; (ii) whereas in group 2 (Al, Fe), the solubility is less than 2% with the highest release at pH 1. Similar solubility patterns in group 1 for Ca, P and Mn suggest a~possible association of the elements in the same minerals, most probably carbonates, which gives phosphorus an unexpected high lability.

  7. Organic composition of PM 2.5 and size-segregated aerosols and their sources during the 2002 Bay Regional Atmospheric Chemistry Experiment (BRACE), Florida, USA

    NASA Astrophysics Data System (ADS)

    Tremblay, Raphaël T.; Riemer, Daniel D.; Zika, Rod G.

    PM 2.5 and size-segregated aerosols were collected in May 2002 as part of the Bay Regional Atmospheric Chemistry Experiment (BRACE), Florida, USA. Aerosol organic composition was used to estimate sources of a series of alkanes and polycyclic aromatic hydrocarbons (PAHs) using chemical indices, hierarchical cluster analysis (HCA) and a chemical mass balance receptor model (CMB). Aerosols were collected on quartz fiber filters (QFF) using a PM 2.5 high volume sampler and on aluminum foil discs using a Micro-Orifice Uniform Deposit Impactor (MOUDI, 50% aerodynamic cut diameters were 18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.315 and 0.171 μm). Target compounds included alkanes and PAHs and were solvent extracted using a mixture of dichloromethane, acetone and hexane, concentrated and then analyzed using a gas chromatograph/mass spectrometer (GC/MS). The target compounds in PM 2.5 were dominated by six sources during the study period: mobile sources (39±5%), coal burning (33±5%), biogenic primary emission (20±2%), oil combustion (5±2%), biomass burning (1.0±0.3%) and an unidentified source (3±2%). Results obtained from the chemical indices, HCA and CMB were in very good agreement with each other. PAH size distributions are presented for days dominated by a same source. Seventy-five percent and 50% of the PAH were found below 1.8 and 0.56 μm, respectively (monthly PAH geometric diameters averaged 0.43 μm). Coarse size PAHs were observed on 1 day (15 May) and were correlated with nitrate and sodium size distribution. It is hypothesized that the PAHs, sodium and nitrate were internally mixed and that the PAHs deposited onto a pre-existing marine aerosol. This transfer process has significant implications for PAH deposition and lifetime and warrants further study.

  8. 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

  9. Ground based chemical characterization of submicron aerosol during the South American Biomass Burning Analysis (SAMBBA) field experiment

    NASA Astrophysics Data System (ADS)

    Brito, Joel; Artaxo, Paulo; Varanda Rizzo, Luciana; Johnson, Ben; Haywood, Jim; Longo, Karla; Freitas, Saulo; Coe, Hugh

    2013-04-01

    This work presents the results of an Aerosol Chemical Speciation Monitor (ACSM) which was successfully operated at a ground station in Porto Velho, Brazil, during the South American Biomass Burning Analysis (SAMBBA). SAMBBA is an international research project based on experimental and modeling activities designed to investigate the impacts of biomass burning emissions on climate, air quality and numerical weather prediction over South America. The measurement program was headed by the deployment of UK's Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft over Brazil during the dry season of 2012. The aircraft operation was coordinated with ground-based measurements at Porto Velho, operated by the University of Sao Paulo. Besides the aerosol chemical speciation, continuous measurements of aerosol size distribution and optical properties were carried out at the ground station, together with CO, CO2 and O3. Filters for trace elements measured by XRF and for OC/EC determined using a Sunset instrument were also collected at the ground based component of SAMBBA. The ACSM collected data for three weeks during September 2012. This period included a strong biomass burning event which showed a marked peak in f60, linked with Levoglucosan, a well-known biomass burning marker. During the biomass burning event, organics concentrations rose up to 80 μg/m3, black carbon close to 6 μg/m3 and CO mixing ratio above 2 ppmv. Fast biomass burning aerosol processing in the atmosphere could be observed through the relative contributions of C2H3O+ vs. CO2+ relative to total organic mass (f44 vs. f43). A clear diurnal variation throughout the sampling period has been observed for organic aerosols with a median peak of 9 μg/m3 at 04:00 LT and a minima of 5 μg/m3 at 18:00 LT. Preliminary results indicate that organics are responsible for 85% of PM1 non-refractory aerosols. The data set will allow the study of interactions between biomass burning and biogenic

  10. 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

  11. 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.

  12. Aerosol chemistry in GLOBE

    NASA Technical Reports Server (NTRS)

    Clarke, Antony D.; Rothermel, Jeffry; Jarzembski, Maurice A.

    1993-01-01

    This task addresses the measurement and understanding of the physical and chemical properties of aerosol in remote regions that are responsible for aerosol backscatter at infrared wavelengths. Because it is representative of other clean areas, the remote Pacific is of extreme interest. Emphasis is on the determination size dependent aerosol properties that are required for modeling backscatter at various wavelengths and upon those features that may be used to help understand the nature, origin, cycling and climatology of these aerosols in the remote troposphere. Empirical relationships will be established between lidar measurements and backscatter derived from the aerosol microphysics as required by the NASA Doppler Lidar Program. This will include the analysis of results from the NASA GLOBE Survey Mission Flight Program. Additional instrument development and deployment will be carried out in order to extend and refine this data base. Identified activities include participation in groundbased and airborne experiments. Progress to date includes participation in, analysis of, and publication of results from Mauna Loa Backscatter Intercomparison Experiment (MABIE) and Global Backscatter Experiment (GLOBE).

  13. 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.

  14. Chemical Composition of the Aerosol Fine Fraction during African Dust Events as part of the Dust ATtACk Experiment in the Caribbean Region

    NASA Astrophysics Data System (ADS)

    Vallejo, Pamela; Formenti, Paola; Desboeufs, Karine; Quiñones, Mariana; Chevaillier, Servanne; Santos, Stephanie; Andrews, Elizabeth; Ogren, John A.; Mayol-Bracero, Olga L.

    2015-04-01

    We present results on the assessment of aerosols' chemical composition at the atmospheric observatory of Cabezas de San Juan in Fajardo, Puerto Rico, during the summers of 2011 and 2012, where periods in the presence and absence of dust were studied under the framework of the Dust-ATtACk (Dust- Aging and Transport, from Africa to the Caribbean) experiment. Dust events were identified through observation and using air-mass back-trajectories, Saharan Air Layer images, measurements of aerosol optical thickness (AOT), in situ scattering and absorption coefficients, and chemical analyses. Results obtained for intense dust events were characterized by higher concentration of coarse particles, higher scattering and absorption coefficients (up to 100 Mm-1 and 5 Mm-1 at 550 and 530 nm, respectively), higher AOT (from 0.4 to 0.8) values, and higher concentration of elements associated with mineral dust (e.g., Si μ3 g/m3 compared to background concentrations of 0.15 μg/m3, obtained from XRF analysis). Elemental composition of the fine fraction (Dp < 1.8 μm), analyzed by ICP-OES, also yielded higher average concentrations during dust events of, for example, Fe (0.045 μg m-3, vs 0.016 μg m-3 during low or no dust). Detailed results of the submicron fraction composition for the carbonaceous aerosol (total carbon, organic carbon, black carbon), total nitrogen, the water-soluble organic carbon, water-soluble ions, and the elemental composition with their possible sources will be presented at the meeting.

  15. 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

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  17. 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

  18. 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 ...

  19. 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

  20. 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.

  1. A synergetic approach for estimating the local direct aerosol forcing: Application to an urban zone during the Expérience sur Site pour Contraindre les Modèles de Pollution et de Transport d'Emission (ESCOMPTE) experiment

    NASA Astrophysics Data System (ADS)

    Roger, J. C.; Mallet, M.; Dubuisson, P.; Cachier, H.; Vermote, E.; Dubovik, O.; Despiau, S.

    2006-07-01

    A method dedicated to the investigation of direct radiative forcing of the main anthropogenic aerosol species (ammonium sulfate, black carbon, particulate organic matter) is presented. We computed the direct radiative aerosol forcing at the top of atmosphere (TOA), at the bottom of atmosphere (BOA), and into the atmospheric layer (ATM). The methodology is based on chemical, photometric, and satellite measurements. We first determined the optical properties of the main aerosol species and then computed their direct radiative impact at local scale. The method was applied to a periurban zone during the Expérience sur Site pour Contraindre les Modèles de Pollution et de Transport d'Emission experiment. Optical computations indicate that the single scattering albedo, for the total aerosol population in the external mixture, is equal to 0.83 ± 0.04 at 550 nm, indicative of a strong absorption of the solar radiation. At the same time the mean asymmetry parameter is equal to 0.59 ± 0.04, and the mean aerosol optical thickness is equal to 0.30 ± 0.02, at 550 nm. The anthropogenic urban aerosol layer reduces significantly the daily surface illumination (-24 W m-2 > ΔFBOA > -47.5 W m-2) by reflection to space (-6 W m-2 > ΔFTOA > -9 W m-2) and by absorption of the solar radiation into the atmosphere (17 W m-2 < ΔFATM < 39 W m-2). The available resulting energy in the atmospheric column heats the lowermost part of the atmosphere from 1.1°K d-1 to 2.8°K d-1. Our study shows that the black carbon particles have a large contribution to the BOA forcing (almost 50% of the total daily forcing), whereas the ammonium sulfate particles contribute only to about 10%. Conversely, the TOA daily forcing is mostly driven by the ammonium sulfate aerosol (around 50%).

  2. 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.

  3. 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.

  4. Aerosol Hygroscopicity Measured in Pristine and Polluted Conditions During the First Year of the GoAmazon 2014/15 Experiment

    NASA Astrophysics Data System (ADS)

    Barbosa, H. M.; Krüger, M. L.; Thalman, R.; Wang, J.; Pauliquevis, T.; Brito, J.; Poeschl, U.; Andreae, M. O.; Martin, S. T.; Artaxo, P.

    2015-12-01

    The effects of aerosol particles on cloud microphysical properties, cloud cover, precipitation, and regional climate are an important aspect of the climate system. The Amazon region is particularly susceptible to changes in number-diameter distributions of the atmospheric particle population because of the low background concentrations and high water vapor levels, indicating a regime of cloud properties that is highly sensitive to aerosol microphysics. This natural regime, different from most other continental areas worldwide, is expected to be perturbed by the interaction of the Manaus urban plume with the natural the natural environment. Studying the effects of this interaction on the cloud and aerosol life cycle is the main objective of the Green Ocean Amazon (GoAmazon) campaign taking place around Manaus-Brazil from January 2014 to December 2015. In this paper we compare the particle hygroscopicity calculated from measurements of size-resolved cloud condensation nuclei performed at three ground sites during the first year of the GoAmazon 2014/15 experiment. Site T3 is about 70 km downwind from Manaus experiencing urban polluted and background conditions; site T2 is just across the Rio Negro from Manaus and CCN measurements were performed there only from 15 August 2014 to 30 Jan 2015; and T0, at the Amazon Tall Tower Observatory (ATTO), is a pristine site about 200 km upwind from Manaus. Our results indicate a lower hygroscopicity under polluted conditions (mean kappa values around 0.14 to 0.16) than under clean conditions (mean kappa around 0.2 to 0.3). At the clean site, it was possible to identify peaks of large sea salt particles with organic coating, while small particles seems to be purely organic. The activation fraction and hygroscopicity will be compared and discussed as a function of particle size. The mean kappa at ATTO is 0.17+-0.05 (mean of June and September) when there is no impact from long range transport from Africa or fresh soot emissions

  5. 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

  6. 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.

  7. Design of experiments and multivariate analysis for evaluation of reversed-phase high-performance liquid chromatography with charged aerosol detection of sucrose caprate regioisomers.

    PubMed

    Lie, Aleksander; Wimmer, Reinhard; Pedersen, Lars Haastrup

    2013-03-15

    The use of step-down gradient elution profiles to improve separation of sucrose caprate regioisomers was investigated as part of the development of a quantitative RP-HPLC analysis method with charged aerosol detection. The investigation was conducted using design-of-experiments methodology and evaluated by multivariate regression analysis. This approach was proven to be useful for systematic method development in HPLC analysis. The gradient elution profiles were described by four variables - two concentration variables and two duration variables. The regression analysis showed that the concentration variables had the most significant effects on retention times, both as individual terms and as part of variable interactions. All the regioisomers exhibited non-linear relationships between eluent acetonitrile concentration and retention time with similar curvatures. Kendall rank correlation coefficients confirmed that the curvatures of the regioisomer curves were highly dependent on each other. Charged aerosol detection provided a mass-sensitivity of 10-100 ng for the sucrose fatty acid ester regioisomers. Resolution deviation (RD) was defined as an aggregate objective function for evaluating the separation of three specific sucrose caprate regioisomers with similar elution properties substituted at positions 6-, 3- and 1'-, respectively. The investigation resulted in the development of elution strategies for separation and quantitative RP-HPLC analysis of regioisomers of sucrose caprate with all eight sucrose caprate regioisomers successfully identified. Thus, resolutions above the level of adequacy for quantification, R(s)≥1.0, were achieved for all regioisomers, both with isocratic and gradient elution strategies. For isocratic elutions, the best separation was achieved with eluent acetonitrile concentration 34%. Gradient elution resulted in a similar RD, but decreased the analysis time by 7-28%. For the gradient resulting in the most desirable combination of

  8. Single-particle detection efficiencies of aerosol time-of-flight mass spectrometry during the North Atlantic marine boundary layer experiment.

    PubMed

    Dall'Osto, Manuel; Harrison, Roy M; Beddows, David C S; Freney, Evelyn J; Heal, Mathew R; Donovan, Robert J

    2006-08-15

    During the North Atlantic marine boundary layer experiment (NAMBLEX) sampling campaign at Mace Head, Ireland, both continental and maritime air masses were sampled. Aerosol was characterized both with a TSI 3800 time-of-flight mass spectrometer (ATOFMS) and a MOUDI microorifice impactor, and particle number counts were measured independently with an aerodynamic particle sizer. The data have been analyzed in order to elucidate factors determining the particle detection efficiencies of the ATOFMS. These are broken down according to the efficiency of the inlet system, the hit efficiency on particles which enter the sensing zone of the instrument and the sensitivity of the measured ion signal to the chemical species. A substantial matrix effect depending on the chemical composition of the aerosol sampled at the time was found, which is reflected in variations in the hit efficiency of particles entering the sensing zone of the instrument with the main desorption-ionization laser. This is in addition to the strong inverse power-law dependence of inlet transmission efficiency on particle diameter. The variation in hit efficiency with particle type is likely attributable to differences in the energetics of laser energy absorption, ablation, and ion formation. However, once variations in both inlet transmission and hit efficiencies are taken into account, no additional matrix dependence of ATOFMS response is required to obtain a linear relationship between the ion signal and the concentration of a particular chemical species. The observations show that a constant mass of material is ionized from each particle, irrespective of size. Consequently the integrated ion signal for a given chemical component and particle size class needs to be increased by a factor related to the cube of particle diameter in order to correlate with the airborne mass of that component. PMID:16955903

  9. Global Aerosol Climatology Project.

    NASA Astrophysics Data System (ADS)

    Mishchenko, Michael; Penner, Joyce; Anderson, Donald

    2002-02-01

    This paper is concerned with uncertainties in the Advanced Very High Resolution Radiometer (AVHRR)-based retrieval of optical depth for heavy smoke aerosol plumes generated from forest fires that occurred in Canada due to a lack of knowledge on their optical properties (single-scattering albedo and asymmetry parameter). Typical values of the optical properties for smoke aerosols derived from such field experiments as Smoke, Clouds, and Radiation-Brazil (SCAR-B); Transport and Atmospheric Chemistry near the Equator-Atlantic (TRACE-A); Biomass Burning Airborne and Spaceborne Experiment in the Amazonas (BASE-A); and Boreal Ecosystem-Atmosphere Study (BOREAS) were first assumed for retrieving smoke optical depths. It is found that the maximum top-of-atmosphere (TOA) reflectance values calculated by models with these aerosol parameters are less than observations whose values are considerably higher. A successful retrieval would require an aerosol model that either has a substantially smaller asymmetry parameter (g < 0.4 versus g > 0.5), or higher single-scattering albedo ( 0.9 versus < 0.9), or both (e.g., g = 0.39 and = 0.91 versus g = 0.57 and = 0.87) than the existing models. Several potential causes were examined including small smoke particle size, low black carbon content, humidity effect, calibration errors, inaccurate surface albedo, mixture of cloud and aerosol layers, etc. A more sound smoke aerosol model is proposed that has a lower content of black carbon (mass ratio = 0.015) and smaller size (mean radius = 0.02 m for dry smoke particles), together with consideration of the effect of relative humidity. Ground-based observations of smoke suggest that for < 2.5 there is an increasing trend in and a decreasing trend in g with increases in , which is consistent with the results of satellite retrievals. Using these relationships as constraints, more plausible values of can be obtained for heavy smoke aerosol. The possibility of smoke-cloud mixtures is also

  10. 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

  11. 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.

  12. 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.

  13. Photoacoustic insight for aerosol light absorption aloft from meteorological aircraft and comparison with particle soot absorption photometer measurements: DOE Southern Great Plains climate research facility and the coastal stratocumulus imposed perturbation experiments

    NASA Astrophysics Data System (ADS)

    Arnott, W. Patrick; Walker, John W.; Moosmüller, Hans; Elleman, Robert A.; Jonsson, Haflidi H.; Buzorius, Gintautas; Conant, William C.; Flagan, Richard C.; Seinfeld, John H.

    2006-03-01

    Aerosol light absorption can be intense close to local sources such as wildland and oil fires, with smoke that disperses into the boundary layer and, with enough lift, into the upper atmosphere where it may be transported around the globe. Filter-based methods such as the Particle Soot Absorption Photometer (PSAP) are most commonly used to quantify aerosol light absorption aloft. This paper reports first measurements of aerosol light absorption aloft with photoacoustic instrumentation (PA). Three examples of aerosol light absorption are presented. The first one illustrates a case of detached layers aloft arising from intercontinental, interoceanic transport of smoke from wildland fires in Siberia to the North American continent and the measurement campaign held at the Department of Energy Atmospheric Radiation Measurement Program Climate Research Facility in north central Oklahoma. Then, two examples of intense local fire smoke light absorption from the Coastal Stratocumulus Imposed Perturbation Experiment near Marina, California, USA, are presented. The first local fire was an oil fire burning in a storage tank near Moss Landing, California, USA, and smoke from this fire was very dark, indicating a low single scattering albedo. By contrast, the second local fire was predominantly burning wood, vegetation, and structures near Fort Ord in Marina, California, USA, and the smoke was very bright, indicating a high single scattering albedo. In all examples, PA measurements at 676 nm were compared with those from a PSAP modified to measure at three wavelengths, including 660 nm.

  14. 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.

  15. 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.

  16. Atmospheric Aerosols

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Lawless, James G. (Technical Monitor)

    1994-01-01

    Aerosols, defined as particles and droplets suspended in air, are always present in the atmosphere. They are part of the earth-atmosphere climate system, because they interact with both incoming solar and outgoing terrestrial radiation. They do this directly through scattering and absorption, and indirectly through effects on clouds. Submicrometer aerosols usually predominate in terms of number of particles per unit volume of air. They have dimensions close to the wavelengths of visible light, and thus scatter radiation from the sun very effectively. They are produced in the atmosphere by chemical reactions of sulfur-, nitrogen- and carbon-containing gases of both natural and anthropogenic origins. Light absorption is dominated by particles containing elemental carbon (soot), produced by incomplete combustion of fossil fuels and by biomass burning. Light-scattering dominates globally, although absorption can be significant at high latitudes, particularly over highly reflective snow- or ice-covered surfaces. Other aerosol substances that may be locally important are those from volcanic eruptions, wildfires and windblown dust.

  17. Toxicity of atmospheric aerosols on marine phytoplankton

    PubMed Central

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

    2009-01-01

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

  18. 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.

  19. Toxicity of atmospheric aerosols on marine phytoplankton.

    PubMed

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

    2009-03-24

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

  20. Effects of aerosol organics on cloud condensation nucleus (CCN) concentration and first indirect aerosol effect

    SciTech Connect

    Wang, J. X.; Lee, Y.- N.; Daum, Peter H.; Jayne, John T.; Alexander, M. L.

    2008-11-03

    Abstract. Aerosol microphysics, chemical composition, and CCN properties were measured on the Department of Energy Gulfstream-1 aircraft during the Marine Stratus/ Stratocumulus Experiment (MASE) conducted over the coastal waters between Point Reyes National Seashore and Monterey Bay, California, in July 2005. Aerosols measured during MASE included free tropospheric aerosols, marine boundary layer aerosols, and aerosols with high organic concentration within a thin layer above the cloud. Closure analysis was carried out for all three types of aerosols by comparing the measured CCN concentrations at 0.2% supersaturation to those predicted based on size distribution and chemical composition using K¨ohler theory. The effect of aerosol organic species on predicted CCN concentration was examined using a single hygroscopicity parameterization.

  1. 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

  2. Influence of aerosols on atmospheric variables in the HARMONIE model

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    The mesoscale HARMONIE model is used to investigate the potential influence of aerosols on weather forecasts, and in particular, on precipitation. The study considers three numerical experiments over the Atlantic-Europe-Northern Africa region during 11-16 August 2010 with the following configurations: (a) no aerosols, (b) only the sea aerosols, and (c) the four types of the aerosols: sea, land, organic, and dust aerosols. The spatio-temporal analysis of forecast differences highlights the impact of aerosols on the prediction of main meteorological variables such as air temperature, humidity, precipitation, and cloud cover as well as their vertical profiles. The variations occur through changes in radiation fluxes and microphysics properties. The sensitivity experiments with the inclusion of climatological aerosol concentrations demonstrate the importance of aerosol effects on weather prediction.

  3. 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.

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

    PubMed

    Wang, P H; 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; Hofmann, D J; Grams, G W; Fuller, W H; Yue, G K

    1989-06-20

    This paper describes an investigation of the comprehensive aerosol correlative measurement experiments conducted between November 1984 and July 1986 for satellite measurement program of the Stratospheric Aerosol and Gas Experiment (SAGE II). The correlative sensors involved in the experiments consist of the NASA Ames Research Center impactor/laser probe, the University of Wyoming dustsonde, and the NASA Langley Research Center airborne 14-inch (36 cm) lidar system. The approach of the analysis is to compare the primary aerosol quantities measured by the ground-based instruments with the calculated ones based on the aerosol size distributions retrieved from the SAGE II aerosol extinction measurements. The analysis shows that the aerosol size distributions derived from the SAGE II observations agree qualitatively with the in situ measurements made by the impactor/laser probe. The SAGE II-derived vertical distributions of the ratio N0.15/N0.25 (where Nr is the cumulative aerosol concentration for particle radii greater than r, in micrometers) and the aerosol backscatter profiles at 0.532- and 0.6943-micrometer lidar wavelengths are shown to agree with the dustsonde and the 14-inch (36-cm) lidar observations, with the differences being within the respective uncertainties of the SAGE II and the other instruments. PMID:11539801

  5. [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. PMID:20518217

  6. 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.

  7. 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.

  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. Understanding the impact of saharan dust aerosols on tropical cyclones

    NASA Astrophysics Data System (ADS)

    Naeger, Aaron

    Genesis of Tropical Cyclones (TCs) in the main development region for Atlantic hurricanes is tied to convection initiated by African easterly waves (AEWs) during Northern hemisphere summer and fall seasons. The main development region is also impacted by dust aerosols transported from the Sahara. It has been hypothesized that dust aerosols can modulate the development of TCs through aerosol-radiation and aerosol-cloud interaction processes. In this study, we investigate the impact of dust aerosols on TC development using the Weather Research and Forecasting model coupled with chemistry (WRF-Chem). We first develop a technique to constrain the WRF-Chem model with a realistic three-dimensional spatial distribution of dust aerosols. The horizontal distribution of dust is specified using the Moderate Resolution Imaging Spectroradiometer (MODIS) derived aerosol products and output from the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model. The vertical distribution of dust is constrained using the Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). We validate our technique through in situ aircraft measurements where both showed aerosol number concentrations from 20-30 cm-3 in the atmosphere for Saharan dust moving over the eastern Atlantic Ocean. Then, we use the satellite data constraint technique to nudge the WRF-Chem aerosol fields throughout the simulation of TC Florence developing over the eastern Atlantic Ocean during September 2006. Three different experiments are conducted where the aerosol-radiation and aerosol-cloud interaction processes are either activated or deactivated in the model while all other model options are identical between the experiments. By comparing the model experiment results, the impact of the aerosol interaction processes on TC development can be understood. The results indicate that dust aerosols can delay or prevent the development of a TC as the minimum sea level pressure of TC Florence was 13 h

  10. 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.

  11. 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.

  12. Satellite Retrieval of Aerosol Properties

    NASA Astrophysics Data System (ADS)

    de Leeuw, G.; Robles Gonzalez, C.; Kusmierczyk-Michulec, J.; Decae, R.

    SATELLITE RETRIEVAL of AEROSOL PROPERTIES G. de Leeuw, C. Robles Gonzalez, J. Kusmierczyk-Michulec and R. Decae TNO Physics and Electronics Laboratory, The Hague, The Netherlands; deleeuw@fel.tno.nl Methods to retrieve aerosol properties over land and over sea were explored. The dual view offered by the ATSR-2 aboard ERS-2 was used by Veefkind et al., 1998. The retrieved AOD (aerosol optical depth) values compare favourably with collocated sun photometer measurements, with an accuracy of 0.06 +/- 0.05 in AOD. An algorithm developed for GOME on ERS-2 takes advantage of the low surface reflection in the UV (Veefkind et al., 2000). AOD values retrieved from ATSR-2 and GOME data over western Europe are consistent. The results were used to produce a map of mean AOD values over Europe for one month (Robles-Gonzalez et al., 2000). The ATSR-2 is al- gorithm is now extended with other aerosol types with the aim to apply it over the In- dian Ocean. A new algorithm is being developed for the Ozone Monitoring Instrument (OMI) to be launched in 2003 on the NASA EOS-AURA satellite. It is expected that, based on the different scattering and absorption properties of various aerosol types, five major aerosol classes can be distinguished. The experience with the retrieval of aerosol properties by using several wavelength bands is used to develop an algorithm for Sciamachy to retrieve aerosol properties both over land and over the ocean which takes advantage of the wavelengths from the UV to the IR. The variation of the AOD with wavelength is described by the Angstrom parameter. The AOD and the Angstrom parameter together yield information on the aerosol size distribution, integrated over the column. Analysis of sunphotometer data indicates a relation between the Angstrom parameter and the mass ratio of certain aerosols (black carbon, organic carbon and sea salt) to the total particulate matter. This relation has been further explored and was applied to satellite data over land to

  13. 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

  14. 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

  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. 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

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. Submicron aerosol size distributions and cloud condensation nuclei concentrations measured at Gosan, Korea, during the Atmospheric Brown Clouds-East Asian Regional Experiment 2005

    NASA Astrophysics Data System (ADS)

    Yum, Seong Soo; Roberts, Greg; Kim, Jong Hwan; Song, Keunyong; Kim, Dohyeong

    2007-11-01

    Submicron aerosol size distributions, CN and CCN concentrations at a constant supersaturation of 0.6% were measured at a relatively remote coastal site at Gosan in Jeju Island, Korea, during the ABC-EAREX from 11 March to 8 April 2005. The average CN concentrations were 6088 ± 3988, 5231 ± 2454 and 3513 ± 1790 cm-3, respectively, for the three major air mass types classified by their origins. The corresponding CCN concentrations were 2393 ± 1156, 2897 ± 1226 and 1843 ± 585 cm-3. The type III air mass was the closest to maritime origins, but these lowest concentrations at Gosan were an order of magnitude higher than those of clean marine boundary layer, indicating that regardless of air mass designation springtime submicron aerosols at Gosan were under steady continental influences. Distinct new particle formation and growth events occurred on 6 d, when clear sky weather conditions prevailed that brought air from northern China, Mongolia or Russia by anticyclonic circulations. Simultaneous occurrence of these events at a western coastal site in the Korean Peninsula 350 km north of Gosan suggests that these events were not local but at least regional-scale events. CCN concentrations were predicted with the aerosol size distributions and the assumption of particles being composed of (NH4)2SO4. The predicted to measured CCN concentration ratio was 1.27 ± 0.29 and the r2 was 0.77 for the whole measurement period. The type I air mass that has the most continental influences showed a slight tendency to overpredict CCN concentrations but the good agreement overall suggests that springtime Gosan aerosols act almost like ammonium sulfate as far as CCN activity is concerned, almost regardless of air mass origin.

  4. 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.

  5. 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.

  6. 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.

  7. 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...

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Tropopsheric Aerosol Chemistry via Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Worsnop, Douglas

    2008-03-01

    A broad overview of size resolved aerosol chemistry in urban, rural and remote regions is evolving from deployment of aerosol mass spectrometers (AMS) throughout the northern hemisphere. Using thermal vaporization and electron impact ionization as universal detector of non-refractory inorganic and organic composition, the accumulation of AMS results represent a library of mass spectral signatures of aerosol chemistry. For organics in particular, mass spectral factor analysis provides a procedure for classifying (and simplifying) complex mixtures composed of the hundreds or thousands of individual compounds. Correlations with parallel gas and aerosol measurements (e.g. GC/MS, HNMR, FTIR) supply additional chemical information needed to interpret mass spectra. The challenge is to separate primary and secondary; anthropogenic, biogenic and biomass burning sources - and subsequent - transformations of aerosol chemistry and microphysics.

  18. Model Intercomparison of Indirect Aerosol Effects

    NASA Technical Reports Server (NTRS)

    Penner, J. E.; Quaas, J.; Storelvmo, T.; Takemura, T.; Boucher, O.; Guo, H.; Kirkevag, A.; Kristjansson, J. E.; Seland, O.

    2006-01-01

    Modeled differences in predicted effects are increasingly used to help quantify the uncertainty of these effects. Here, we examine modeled differences in the aerosol indirect effect in a series of experiments that help to quantify how and why model-predicted aerosol indirect forcing varies between models. The experiments start with an experiment in which aerosol concentrations, the parameterization of droplet concentrations and the autoconversion scheme are all specified and end with an experiment that examines the predicted aerosol indirect forcing when only aerosol sources are specified. Although there are large differences in the predicted liquid water path among the models, the predicted aerosol first indirect effect for the first experiment is rather similar, about -0.6 W/sq m to -0.7 W/sq m. Changes to the autoconversion scheme can lead to large changes in the liquid water path of the models and to the response of the liquid water path to changes in aerosols. Adding an autoconversion scheme that depends on the droplet concentration caused a larger (negative) change in net outgoing shortwave radiation compared to the 1st indirect effect, and the increase varied from only 22% to more than a factor of three. The change in net shortwave forcing in the models due to varying the autoconversion scheme depends on the liquid water content of the clouds as well as their predicted droplet concentrations, and both increases and decreases in the net shortwave forcing can occur when autoconversion schemes are changed. The parameterization of cloud fraction within models is not sensitive to the aerosol concentration, and, therefore, the response of the modeled cloud fraction within the present models appears to be smaller than that which would be associated with model "noise". The prediction of aerosol concentrations, given a fixed set of sources, leads to some of the largest differences in the predicted aerosol indirect radiative forcing among the models, with values of

  19. SAMPLING DURATION DEPENDENCE OF SEMI-CONTINUOUS ORGANIC CARBON MEASUREMENTS ON STEADY STATE SECONDARY ORGANIC AEROSOLS

    EPA Science Inventory

    Semi-continuous organic carbon concentrations were measured through several experiments of statically generated secondary organic aerosol formed by hydrocarbon + NOx irradiations. Repeated, randomized measurements of these steady state aerosols reveal decreases in the observed c...

  20. 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

  1. PIXE Analysis of Indoor Aerosols

    NASA Astrophysics Data System (ADS)

    Johnson, Christopher; Turley, Colin; Moore, Robert; Battaglia, Maria; Labrake, Scott; Vineyard, Michael

    2011-10-01

    We have performed a proton-induced X-ray emission (PIXE) analysis of aerosol samples collected in academic buildings at Union College to investigate the air quality in these buildings and the effectiveness of their air filtration systems. This is also the commissioning experiment for a new scattering chamber in the Union College Ion-Beam Analysis Laboratory. The aerosol samples were collected on Kapton foils using a nine-stage cascade impactor that separates particles according to their aerodynamic size. The foils were bombarded with beams of 2.2-MeV protons from the Union College 1.1-MV Pelletron Accelerator and the X-ray products were detected with an Amptek silicon drift detector. After subtracting the contribution from the Kapton foils, the X-ray energy spectra of the aerosol samples were analyzed using GUPIX software to determine the elemental concentrations of the samples. We will describe the collection of the aerosol samples, discuss the PIXE analysis, and present the results.

  2. Aerosol phase transformation in the atmosphere

    SciTech Connect

    Tang, I.N.; Munkelwitz, H.R.

    1992-09-01

    Ambient aerosols are frequently composed of hygroscopic inorganic salts such as chlorides, sulfates and nitrates in either pure or mixed forms. Such inorganic salt aerosols exhibit the properties of deliquescence and efflorescence in air. The phase transformation from a solid particle to a saline droplet usually occurs spontaneously when atmospheric relative humidity reaches a level specific to the chemical composition of the aerosol particle. Conversely, when relative humidity decreases and becomes low enough, a saline droplet will evaporate and suddenly crystallize, expelling all its water content. Information on the composition and temperature dependence of these properties is required in mathematical models for describing the dynamic and transport behavior of ambient aerosols. Experiments are carried out in the temperature range 5--35{degrees}C, using single particles individually suspended in an electrodynamic cell that can be evacuated and back filled with water vapor. The phase transformation of the aerosol particle is monitored by laser light scattering and the relative humidity at the transition point is determined by directly measuring the water vapor pressure in the cell. Results are obtained for particles containing either a single salt or a preselected mixture of NaCl, KCl, NaNO{sub 3}, Na{sub 2}SO{sub 4} and (NH{sub 4}){sub 2}SO{sub 4}, which are common constituents of ambient aerosols. A theoretical model on the composition and temperature dependence of the deliquescence properties is developed for single and two-salt aerosol systems.

  3. 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

  4. 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).

  5. Aerosol chamber and modelling studies on the reaction of soot aerosols with ozone

    SciTech Connect

    Moehler, O.; Naumann, K.H.; Saathoff, H.

    1995-12-31

    Heterogeneous processes in atmospheric aerosols are known to play important roles in the chemical transformation of air pollutants. Especially irregularly shaped aerosol particles like soot have large surface areas to interact with trace gases. The overall efficiency of those processes depends on various parameters like the particle shape, the chemical surface conditions, the surface reaction mechanisms and the gas transport processes to and from the surface. The shape and surface of soot particles are transformed due to their heterogeneous chemical activity. Therefore, the surface reaction efficiency of atmospheric soot particles also depends on their age and history. The scope of this work is to investigate the ozone depletion potential of soot particles at typical atmospheric conditions. The experiments are carried out in a cylindrical aerosol vessel with a volume of 3.7 m{sup 3}. The soot aerosol is produced with a sparc generator and introduced into the aerosol vessel together with the ozone. The variation of the number concentration, the mass concentration and the size distribution of the soot aerosol within the aerosol vessel is measured and electron micrographs are taken to obtain information on the particle morphology. The ozone concentration is continuously monitored by UV-absorption. The experimental data are compared with model results to analyze the physical and chemical processes in the aerosol system in more detail. The aerosol model developed at our institute is based on the concept of fractal geometry and calculates the dynamic behaviour of irregularly shaped aerosols. More recently, the model was extended to describe the interaction of the aerosol particles with gases. This paper summarizes first results of the experimental and modelling work. The possible impact on tropospheric chemistry will be discussed.

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

    DOE PAGESBeta

    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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Airborne Aerosol Closure Studies During PRIDE

    NASA Technical Reports Server (NTRS)

    Redemann, Jens; Livingston, John M.; Russell, Philip B.; Schmid, Beat; Reid, Jeff

    2000-01-01

    The Puerto Rico Dust Experiment (PRIDE) was conducted during June/July of 2000 to study the properties of Saharan dust aerosols transported across the Atlantic Ocean to the Caribbean Islands. During PRIDE, the NASA Ames Research Center six-channel (380 - 1020 nm) airborne autotracking sunphotometer (AATS-6) was operated aboard a Piper Navajo airplane alongside a suite of in situ aerosol instruments. The in situ aerosol instrumentation relevant to this paper included a Forward Scattering Spectrometer Probe (FSSP-100) and a Passive Cavity Aerosol Spectrometer Probe (PCASP), covering the radius range of approx. 0.05 to 10 microns. The simultaneous and collocated measurement of multi-spectral aerosol optical depth and in situ particle size distribution data permits a variety of closure studies. For example, vertical profiles of aerosol optical depth obtained during local aircraft ascents and descents can be differentiated with respect to altitude and compared to extinction profiles calculated using the in situ particle size distribution data (and reasonable estimates of the aerosol index of refraction). Additionally, aerosol extinction (optical depth) spectra can be inverted to retrieve estimates of the particle size distributions, which can be compared directly to the in situ size distributions. In this paper we will report on such closure studies using data from a select number of vertical profiles at Cabras Island, Puerto Rico, including measurements in distinct Saharan Dust Layers. Preliminary results show good agreement to within 30% between mid-visible aerosol extinction derived from the AATS-6 optical depth profiles and extinction profiles forward calculated using 60s-average in situ particle size distributions and standard Saharan dust aerosol refractive indices published in the literature. In agreement with tendencies observed in previous studies, our initial results show an underestimate of aerosol extinction calculated based on the in situ size distributions

  14. 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).

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. SAGE II (Stratospheric Aerosol and Gas Experiment) observations of polar stratospheric clouds near 50 degree N January 31-February 2, 1989

    SciTech Connect

    Pitts, M.C. ); Poole, L.R.; McCormick, M.P. )

    1990-03-01

    Polar stratospheric clouds (PSCs) form at very cold temperatures which typically occur only at high latitudes during local winter. However, meteorological circumstances in the Arctic during late January 1989 led to PSC formation unusually far to the south, at latitudes (near 50{degree}N) being sampled during the period (January 31-February 2) by the orbiting SAGE II instrument. These unusual PSC sightings and the evolution of meteorological conditions which produced the episode are described. Profiles of SAGE II extinction measurements at 0.525 and 1.02 {mu}m show clear signatures of PSCs and indicate that the cloud particles were considerably larger than the background aerosol. It is most important to note that the clouds were sighted at a latitude where there was extensive sunlight, thus increasing the likelihood of ozone loss both locally and downstream due to enhancements in reactive chlorine expected from heterogeneous chemical processing within the PSCs.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Aerosol droplets: Nucleation dynamics and photokinetics

    NASA Astrophysics Data System (ADS)

    Signorell, Ruth

    This talk addresses two fundamental aerosol processes that play a pivotal role in atmospheric processes: The formation dynamics of aerosol particles from neutral gas phase precursors and photochemical reactions in small aerosol droplets induced by ultraviolet and visible light. Nucleation is the rate determining step of aerosol particle formation. The idea behind nucleation is that supersaturation of a gas leads to the formation of a critical cluster, which quickly grows into larger aerosol particles. We discuss an experiment for studying the size and chemical composition of critical clusters at the molecular level. Much of the chemistry happening in planetary atmospheres is driven by sunlight. Photochemical reactions in small aerosol particles play a peculiar role in this context. Sunlight is strongly focused inside these particles which leads to a natural increase in the rates of photochemical reactions in small particles compared with the bulk. This ubiquitous phenomenon has been recognised but so far escaped direct observation and quantification. The development of a new experimental setup has finally made it possible to directly observe this nanofocusing effect in droplet photokinetics. This work was supported by the Swiss National Science Foundation (SNSF) and ETH Zurich.

  13. Atmospheric aerosol and Doppler lidar studies

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  14. 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.

  15. 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.

  16. HOUSTON AEROSOL CHARACTERIZATION STUDY

    EPA Science Inventory

    An intensive field study of ambient aerosols was conducted in Houston between September 14 and October 14, 1978. Measurements at 12 sites were made using (1) two relocatable monitoring systems instrumented for aerosol and gaseous pollutants, (2) a network of high volume samplers ...

  17. 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, ...

  18. 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.

  19. 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.

  20. Do anthropogenic, continental or coastal aerosol sources impact on a marine aerosol signature at Mace Head?

    NASA Astrophysics Data System (ADS)

    O'Dowd, C.; Ceburnis, D.; Ovadnevaite, J.; Vaishya, A.; Rinaldi, M.; Facchini, M. C.

    2014-10-01

    Atmospheric aerosols have been sampled and characterised at the Mace Head north-east (NE) Atlantic atmospheric research station since 1958, with many interesting phenomena being discovered. However, with the range of new discoveries and scientific advances, there has been a range of concomitant criticisms challenging the representativeness of aerosol sampled at the station compared to that of aerosol over the pristine open-ocean. Two recurring criticisms relate to the lack of representativeness due to potentially enhanced coastal sources, possibly leading to artificially high values of aerosol concentrations, and to the influence of long-range transport of anthropogenic or continental aerosol and its potential dominance over, or perturbation of, a natural marine aerosol signal. Here, we review the results of previous experimental studies on marine aerosols over the NE Atlantic and at Mace Head with the aim of evaluating their representativeness relative to that of a pristine open-ocean aerosol, i.e. with negligible anthropogenic/continental influence. Particular focus is given to submicron organic matter (OM) aerosol. In summary, no correlation was found between OM and black carbon (BC) in marine air conforming to clean-air sampling criteria, either at BC levels of 0-15 or 15-50 ng m-3, suggesting that OM concentrations, up to observed peak values of 3.8 μg m-3, are predominantly natural in origin. Sophisticated carbon isotope analysis and aerosol mass spectral finger printing techniques corroborate the conclusion that there is a predominant natural source of OM, with 80% biogenic source apportionment being observed for general clean-air conditions, rising to ∼98% during specific primary marine organic plumes when peak OM mass concentrations > 3 μg m-3 are observed. Similarly, a maximum contribution of 20% OM mass coming from non-marine sources was established by dual carbon isotope analysis. Further, analysis of a series of experiments conducted at Mace Head

  1. The effect of organic aerosol material on aerosol reactivity towards ozone

    NASA Astrophysics Data System (ADS)

    Batenburg, Anneke; Gaston, Cassandra; Thornton, Joel; Virtanen, Annele

    2015-04-01

    After aerosol particles are formed or emitted into the atmosphere, heterogeneous reactions with gaseous oxidants cause them to 'age'. Aging can change aerosol properties, such as the hygroscopicity, which is an important parameter in how the particles scatter radiation and form clouds. Conversely, heterogeneous reactions on aerosol particles play a significant role in the cycles of various atmospheric trace gases. Organic compounds, a large part of the total global aerosol matter, can exist in liquid or amorphous (semi)solid physical phases. Different groups have shown that reactions with ozone (O3) can be limited by bulk diffusion in organic aerosol, particularly in viscous, (semi)solid materials, and that organic coatings alter the surface interactions between gas and aerosol particles. We aim to better understand and quantify how the viscosity and phase of organic aerosol matter affect gas-particle interactions. We have chosen the reaction of O3 with particles composed of a potassium iodide (KI) core and a variable organic coating as a model system. The reaction is studied in an aerosol flow reactor that consists of a laminar flow tube and a movable, axial injector for the injection of O3. The aerosol-containing air is inserted at the tube's top. The interaction length (and therefore time), between the particles and the O3 can be varied by moving the injector. Alternatively, the production of aerosol particles can be modulated. The remaining O3 concentration is monitored from the bottom of the tube and particle concentrations are measured simultaneously, which allows us to calculate the reactive uptake coefficient γ. We performed exploratory experiments with internally mixed KI and polyethylene glycol (PEG) particles at the University of Washington (UW) in a setup with a residence time around 50 s. Aerosol particles were generated in an atomizer from solutions with varying concentrations of KI and PEG and inserted into the flow tube after they were diluted and

  2. 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.

  3. 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.

  4. Chemistry of organic aerosol formation in urban atmospheres. Final report

    SciTech Connect

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

    1994-04-04

    Aerosol formation from the photooxidation of A-pinene/NOx and B-pinene/NOx mixtures has been investigated in a series of outdoor smog chamber experiments. Both hydrocarbons are potent aerosol formers and in areas containing significant vegetation, terpenes are estimated to be a significant contributor to secondary organic aerosol formation. To model organic aerosol formation, estimates of the vapor pressures of the condensable species are needed. To measure the vapor pressures of the low volatility species characteristic of organic aerosols the Tandem Differential Mobility Analyzer (TDMA) method introduced by Liu and McMurray has been further developed for this task. Initial experiments with compounds of known vapor pressure confirm the usefulness of the method.

  5. 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,...

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. SOURCES OF ORGANIC AEROSOL: SEMIVOLATILE EMISSIONS AND PHOTOCHEMICAL AGING

    EPA Science Inventory

    The proposed research integrates emissions testing, smog chamber experiments, and regional chemical transport models (CTMs) to investigate the sources of organic aerosol in urban and regional environments.

  11. 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...

  12. 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.

  13. 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.

  14. 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. PMID:27149690

  15. 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.

  16. 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.

  17. 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.

  18. Do anthropogenic or coastal aerosol sources impact on a clean marine aerosol signature at Mace Head?

    NASA Astrophysics Data System (ADS)

    O'Dowd, C.; Ceburnis, D.; Ovadnevaite, J.; Rinaldi, M.; Facchini, M. C.

    2013-03-01

    Atmospheric aerosols have been sampled and characterised at the Mace Head North East (N.E.) Atlantic atmospheric research station since 1958, with many interesting phenomena being discovered. However, with the range of new discoveries and scientific advances, there has been a range of concomitant criticisms challenging the representativeness of aerosol sampled at the station to that of aerosol over the open ocean. Two recurring criticisms relate to the lack of representativeness due to enhanced coastal sources, thereby leading to artificially high values to aerosol parameters, and to the influence of long-range transport of anthropogenic aerosol and its potential dominance over, or drowning-out of, a natural marine aerosol signal. Here we review the results of previous experimental studies into marine aerosols over the N.E. Atlantic and at Mace Head with the aim of evaluating their representativeness relative to that of an open ocean aerosol with negligible anthropogenic influence. Particular focus is given to organic matter (OM) aerosol. In summary, no correlation was found between OM and black carbon (BC) either at BC levels of 0-15 or 15-50 ng m-3, suggesting that OM concentrations up to peak values of 3.8 μg m-3 are predominantly natural in origin. Sophisticated carbon isotope analysis and aerosol mass spectral finger printing corroborate the natural source of OM with 80% biogenic source apportionment being observed for general clean air conditions, rising to 98% during specific primary marine organic plumes when peak concentrations >3 μg m-3 are observed. A range of other experiments are discussed which corroborate the dominance of a marine signal under Mace Head clean air criteria along. Further, analysis of a series of experiments conducted at Mace Head conclude that negligible coastal, surf zone, or tidal effects are discernible in the submicron size range for sampling heights of 7 m and above. The Mace Head clean air criteria ensures anthropogenic and

  19. Efficiency of aerosol collection on wires exposed in the stratosphere

    NASA Technical Reports Server (NTRS)

    Lem, H. Y.; Farlow, N. H.

    1979-01-01

    The theory of inertial impaction is briefly presented. Stratospheric aerosol research experiments were performed duplicating Wong et al. experiments. The use of the curve of inertial parameters vs particle collection efficiency, derived from Wong et al., was found to be justified. The results show that stratospheric aerosol particles of all sizes are collectible by wire impaction technique. Curves and tables are presented and used to correct particle counts for collection efficiencies less than 100%.

  20. 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

  1. 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.

  2. 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.

  3. Aerosol lenses propagation model.

    PubMed

    Tremblay, Grégoire; Roy, Gilles

    2011-09-01

    We propose a model based on the properties of cascading lenses modulation transfer function (MTF) to reproduce the irradiance of a screen illuminated through a dense aerosol cloud. In this model, the aerosol cloud is broken into multiple thin layers considered as individual lenses. The screen irradiance generated by these individual layers is equivalent to the point-spread function (PSF) of each aerosol lens. Taking the Fourier transform of the PSF as a MTF, we cascade the lenses MTF to find the cloud MTF. The screen irradiance is found with the Fourier transform of this MTF. We show the derivation of the model and we compare the results with the Undique Monte Carlo simulator for four aerosols at three optical depths. The model is in agreement with the Monte Carlo for all the cases tested. PMID:21886230

  4. The Use of MODIS Instrument on the EOS-Terra Satellite to Assess the Impact of Aerosol on Climate

    NASA Technical Reports Server (NTRS)

    Kaufman, Y.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Terra will derive the aerosol optical thickness and properties. The aerosol properties can be used to distinguish between natural and human-made aerosol. In the polar orbit Terra will measure aerosol only once a day, around 10:30 am. How will we use this information to study the global radiative impacts of aerosol on climate? We shall present a strategy to address this problem. It includes the following steps: 1) From the Terra aerosol optical thickness and size distribution model we derive the effect of aerosol on reflection of solar radiation at the top of the atmosphere. In a sensitivity study we show that the effect of aerosol on solar fluxes can be derived 10 times more accurately from the MODIS data than derivation of the optical thickness itself. Applications to data over several regions will be given. 2) Using 1/2 million AERONET global data of aerosol spectral optical thickness we show that the aerosol optical thickness and properties during the Terra 10:30 pass are equivalent to the daily average. Due to the aerosol lifetime of several days measurements at this time of the day are enough to assess the daily impact of aerosol on radiation. 3) Aerosol impact on the top of the atmosphere is only part of the climate question. The INDOEX experiment showed that addressing the impact of aerosol on climate, requires also measurements of the aerosol forcing at the surface. This can be done by a combination of measurements of MODIS and AERONET data.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Reallocation in modal aerosol models: impacts on predicting aerosol radiative effects

    NASA Astrophysics Data System (ADS)

    Korhola, T.; Kokkola, H.; Korhonen, H.; Partanen, A.-I.; Laaksonen, A.; Lehtinen, K. E. J.; Romakkaniemi, S.

    2014-01-01

    Atmospheric models often represent the aerosol particle size distribution with a modal approach, in which particles are described with log-normal modes within predetermined size ranges. This approach reallocates particles numerically from one mode to another for example during particle growth, potentially leading to artificial changes in the aerosol size distribution. In this study we analysed how the modal reallocation affects climate-relevant variables: cloud droplet number concentration (CDNC), aerosol-cloud interaction parameter (ACI) and light extinction coefficient (qext). The ACI parameter gives the response of CDNC to a change in total aerosol number concentration. We compared these variables between a modal model (with and without reallocation routines) and a high resolution sectional model, which was considered a reference model. We analysed the relative differences in the chosen variables in four experiments designed to assess the influence of atmospheric aerosol processes. We find that limiting the allowed size ranges of the modes, and subsequent remapping of the distribution, leads almost always to an underestimation of cloud droplet number concentrations (by up to 100%) and an overestimation of light extinction (by up to 20%). On the other hand, the aerosol-cloud interaction parameter can be either over- or underestimated by the reallocating model, depending on the conditions. For example, in the case of atmospheric new particle formation events followed by rapid particle growth, the reallocation can cause on average a 10% overestimation of the ACI parameter. Thus it is shown that the reallocation affects the ability of a model to estimate aerosol climate effects accurately, and this should be taken into account when using and developing aerosol models.

  14. Can Aerosol Forcing Compensate the Greenhouse Gas Warming?

    NASA Astrophysics Data System (ADS)

    Feichter, J.; Liepert, B.; Lohmann, U.; Roeckner, E.

    2002-12-01

    Fossil fuel combustion and biomass burning modify the chemical composition of the atmosphere by enhancing aerosol particles (AP) and greenhouse gas (GHG) concentrations. These changes induce opposite effects on temperature, i.e. warming through increasing GHG levels and cooling through increasing AP concentrations. While increasing GHGs tend to enhance the hydrological cycle, the APs have the opposite effect: First, through climate cooling and, second, through a reduction in solar radiation absorbed at the Earth's surface. Moreover, in contrast to GHGs, there is a strong coupling between aerosols, clouds and precipitation formation such that AP induced changes in the hydrological cycle feed back on the aerosol distribution. We performed simulations with of a low-resolution version (T30 spectral truncation) of the atmospheric general circulation model ECHAM4 coupled to an ocean mixed layer model and a thermodynamic sea ice model. Furthermore, the atmospheric model solves prognostic equations for the mass mixing ratio of dimethyl sulfide, sulfur dioxide, sulfate aerosols, organic and black carbon aerosols, mineral dust, sea-salt, cloud liquid water, cloud ice and for the cloud droplet and ice crystal number concentration. It also includes a fully coupled aerosol-cloud microphysics module. We performed three pairs of climate equilibrium experiments. Each pair consists of two simulations: one represents pre-industrial (year 1870) (PI) and one present-day (early 1980's) conditions (PD). In the first pair we change the greenhouse gas (GHG) concentrations and apply the model's operational aerosol climatology as PD conditions. In the second pair we calculate the aerosol interactively and we change the anthropogenic aerosol and aerosol precursor emissions and keep the GHG concentrations fixed to PD level. In the third pair we change both, GHG concentrations and aerosol emissions. The climate responses and the basic mechanisms will be discussed.

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. North Atlantic Aerosol Radiative Effects Based on Satellite Measurements and Aerosol Intensive Properties from TARFOX and ACE-2

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.; Russell, Philip B.

    2000-01-01

    We estimate the impact of North Atlantic aerosols on the net shortwave flux at the tropopause by combining maps of satellite-derived aerosol optical depth (AOD) with model aerosol properties. We exclude African dust, primarily by restricting latitudes to 25-60 N. Aerosol properties were determined via column closure analyses in two recent experiments, TARFOX and ACE 2. The analyses use in situ measurements of aerosol composition and air- and ship-borne sunphotometer measurements of AOD spectra. The resulting aerosol model yields computed flux sensitivities (dFlux/dAOD) that agree with measurements by airborne flux radiometers in TARFOX. It has a midvisible single-scattering albedo of 0.9, which is in the range obtained from in situ measurements of aerosol scattering and absorption in both TARFOX and ACE 2. Combining seasonal maps of AVHRR-derived midvisible AOD with the aerosol model yields maps of 24-hour average net radiative flux changes at the tropopause. For cloud-free conditions, results range from -9 W/sq m near the eastern US coastline in the summer to -1 W/sq m in the mid-Atlantic during winter; the regional annual average is -3.5 W/sq m. Using a non- absorbing aerosol model increases these values by about 30%. We estimate the effect of clouds using ISCCP cloud-fraction maps. Because ISCCP midlatitude North Atlantic cloud fractions are relatively large, they greatly reduce the computed aerosol-induced flux changes. For example, the regional annual average decreases from -3.5 W/sq m to -0.8 W/sq m. We compare results to previous model calculations for a variety of aerosol types.

  20. 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.

  1. Global Lidar Observations of Aerosol Distribution and Radiative Influence

    NASA Technical Reports Server (NTRS)

    Spinhirne, James; Starr, David OC. (Technical Monitor)

    2001-01-01

    A very visible impact of human activities is the brownish aerosol haze that pervades many industrialized regions as well as areas in the subtropics and tropics where biomass burning occurs. Well known examples are the Asian Brown Cloud, Arctic Haze and East Coast Haze. Atmospheric transport transforms this haze into regional and hemispheric aerosol layers of significant concentrations. The overall impact on the radiation balance of the atmosphere, surface solar irradiance and other meteorology factors is recognized as a major uncertainty for climate change. In order to understand the impact, the global distribution of aerosol and their properties must be known. . A missing element of observations, but critical for understanding transport has been the height distribution of aerosol. Lidar measurements of aerosol height distribution have been important in GLOBE, ACE, INDOEX and other field studies A network of continuously operating eye safe lidar ground sites has now been established for baseline aerosol profiling. In 2002 NASA will launch the Geoscience Laser Altimeter System (GLAS) mission which will provide for the first time global observations of the height distribution of aerosol. The combination of these and other modem satellite observations, field experiments and models of global aerosol composition and transport should begin to unravel the impacts of particles in the atmosphere.

  2. 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.

  3. Distinct effects of anthropogenic aerosols on the East Asian summer monsoon between multi-decadal strong and weak monsoon stages: Effects of aerosols on EASM

    DOE PAGESBeta

    Xie, Xiaoning; Wang, Hongli; Liu, Xiaodong; Li, Jiandong; Wang, Zhaosheng; Liu, Yangang

    2016-06-18

    Industrial emissions of anthropogenic aerosols over East Asia have greatly increased in recent decades, and so the interactions between atmospheric aerosols and the East Asian summer monsoon (EASM) have attracted enormous attention. In order 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 aerosolmore » 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. Moreover, 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.« less

  4. 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.

  5. The Effects of Aerosols on Intense Convective Precipitation in the Northeastern U.S.

    SciTech Connect

    Ntelekos, Alexandros A.; Smith, James S.; Donner, Leo J.; Fast, Jerome D.; Gustafson, William I.; Chapman, Elaine G.; Krajewski, Witold F.

    2009-08-03

    A fully coupled meteorology-chemistry-aerosol mesoscale model (WRF-Chem) is used to assess the effects of aerosols on intense convective precipitation over the northeastern United States. Numerical experiments are performed for three intense convective storm days and for two scenarios representing “typical” and “low” aerosol conditions. The results of the simulations suggest that increasing concentrations of aerosols can lead to either enhancement or suppression of precipitation. Quantification of the aerosol effect is sensitive to the metric used due to a shift of rainfall accumulation distribution when realistic aerosol concentrations are included in the simulations. Maximum rainfall accumulation amounts and areas with rainfall accumulations exceeding specified thresholds provide robust metrics of the aerosol effect on convective precipitation. Storms developing over areas with medium to low aerosol concentrations showed a suppression effect on rainfall independent of the meteorologic environment. Storms developing in areas of relatively high particulate concentrations showed enhancement of rainfall when there were simultaneous high values of CAPE, relative humidity and wind shear. In these cases, elevated aerosol concentrations resulted in stronger updrafts and downdrafts and more coherent organization of convection. For the extreme case, maximum rainfall accumulation differences exceeded 40 mm. The modeling results suggest that areas of the northeastern U.S. urban corridor that are close or downwind of intense sources of aerosols, could be more favorable for rainfall enhancement due to aerosols for the aerosol concentrations typical of this area.

  6. Secondary Organic Aerosol Formation in Aerosol Water by Photochemical Reactions of Gaseous Mixture of Monoterpene and Hydrogen Peroxide

    NASA Astrophysics Data System (ADS)

    Lim, H.; Yi, S.; Park, J.; Cho, H.; Jung, K.

    2011-12-01

    There exist large uncertainties in model predictions for climate change and regional air quality. It could be caused by incomplete integration of secondary organic aerosol (SOA) formation in atmospheric chemical models. Recent laboratory studies have found SOA formation through chemical reactions on aerosol surface and in aerosol water. Water soluble organics formed by photochemical degradation of biogenic organics including isoprene and anthropogenic aromatics are predicted to form substantial amount of SOA through the newly found pathways. Although SOA formation in bulk aqueous solution was reported for laboratory experiments of various precursors (e.g., water soluble carbonyls and phenols), little is known for SOA formation in real aerosol water. In this study, photochemical reactions of the gaseous mixture of monoterpene and hydrogen peroxide were examined to investigate SOA formation through reactions in real aerosol phase water. SOA formation was conducted using a flow tube reactor (ID 30 cm x L 150 cm, FEP) and a smog chamber using FEP film in the presence of dry and wet seed particles. Acidity and chemical composition of seed aerosol were also controlled as important parameters influencing SOA formation. Particle size distribution and aerosol composition were analyzed to account for differences in SOA formation mechanisms and yields for dry and wet particles. The differences might be mainly associated with SOA formation in aerosol phase water. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2011-0000221).

  7. 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

  8. Space-borne Observations of Aerosols

    NASA Astrophysics Data System (ADS)

    Kaufman, Y. J.; Tanre, D.; Coakley, J. A.; Fraser, R. S.

    2005-12-01

    As early as 1963, photographs of the twilight horizon from the Vostok-6 spaceship were used by G. V. Rozenberg and V. V. Nikolaeva-Tereshkova to derive profiles of stratospheric aerosols. The launch of the ATS III satellite in 1967 sparked interest in using satellites to observe aerosol emission, transport, and their effects on climate, precipitation and health. The first use of autonomous satellites in aerosol research appears to be by Toby Carlson and Joe Prospero who tracked dust from the Sahara to the Americas in the early `70s using ATS III images. The launch of the calibrated Landsat instrument in 1972 allowed Bob Fraser to perform quantitative analyses of dust column concentrations for individual scenes. GOES launched in 1975 provided hourly data that allowed Walter Lyons and J.C. Dooley in the late 70's to report on the transport of sulfate air pollution which was later followed by estimates of the export of sulfate aerosol from the US to the Atlantic Ocean. With the launch of SAGE in 1979, Pat McCormick and co-workers began long term observations of statospheric aerosols. The launch of TIROS(N) and the AVHRR in 1979 marked the start of concerted efforts by Larry Stowe and his colleagues to produce operationally an aerosol product over oceans from the NOAA polar orbiting satellite. With the launch of the Earth Radiation Budget Experiment scanners in the late 1980's, Sundar Christopher and his colleagues began linking AVHRR-derived aerosol burdens to their effects on the Earth's radiation budget. A remarkable aspect of this early work is that instruments like the AVHRR, Landsat, and GOES imager were not originally designed to perform quantitative estimates of aerosol properties. In fact, corrections for the effects of aerosols in determining ocean reflectances implemented primarily through the work of Howard Gordon, facilitated much improved pictures of chlorophyll in the upper oceans than had been hoped for from CZCS data collected in the late 70's. This

  9. 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.

  10. SURVIVAL OF BACTERIA DURING AEROSOLIZATION

    EPA Science Inventory

    One form of commercial application of microorganisms, including genetically engineered microorganisms is as an aerosol. To study the effect of aerosol-induced stress on bacterial survival, nonrecombinant spontaneous antibiotic-resistant mutants of four organisms, Enterobacter clo...

  11. Other medications for aerosol delivery.

    PubMed

    Rubin, Bruce K

    2006-01-01

    Although aerosol therapy is most commonly used to treat asthma and COPD, there are a large number of aerosol medications now used or in development for other diseases. Mucoactive agents have long been available by aerosol, but now we have truly effective drugs to improve effective airway clearance including dornase alfa, hyperosmolar saline, and aerosol surfactant. Inhaled antibiotics are available for the treatment of cystic fibrosis, bronchiectasis and other chronic airway infections. With the development of devices that can target aerosol to the deep lung, the opportunity to deliver medications systemically by the aerosol route has become a reality. Insulin, recently approved in the US as aerosol therapy, and other peptides are systemically absorbed from the distal airway and alveolus. Aerosol gene transfer therapy to correct abnormalities associated with cystic fibrosis, primary ciliary dyskinesia and other airway diseases also holds great potential. PMID:16798603

  12. 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.

  13. 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%.

  14. 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%.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Remote Sensing of Aerosol and their Radiative Forcing of Climate

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram J.; Tanre, Didier; Remer, Lorraine A.

    1999-01-01

    spectral flux reaching the surface. Effort to introduce remote sensing from lidars will literally additional dimension to aerosol remote sensing. The vertical dimension is a critical link between the global satellite observations and modeling of aerosol transport. Lidars are also critical to study aerosol impact on cloud microphysics and reflectance. Both lidar ground networks and satellite systems are in development. This new capability is expected to put remote sensing in the forefront of aerosol and climate studies. Together with field experiments, chemical analysis and chemical transport models we anticipate, in the next decade, to be able to resolve some of the outstanding questions regarding the role of aerosol in climate, in atmospheric chemistry and its influence on human health and life on this planet.

  20. 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.

  1. Development of synthetic GOES-R ABI aerosol products

    NASA Astrophysics Data System (ADS)

    Hoff, R. M.; Kondragunta, S.; Ciren, P.; Xu, C.; Zhang, H.; Huff, A.

    2014-09-01

    An Observing Systems Simulation Experiment (OSSE) for GOES-R Advanced Baseline Imager (ABI) aerosol products has been carried out. The generation of simulated data involves prediction of aerosol chemical composition fields at one-hour resolution and 12 km × 12 km spacing. These data are then fed to a radiative transfer model to simulate the on-orbit radiances that the GOES-R ABI will see in six channels. This allows the ABI aerosol algorithm to be tested to produce products that will be available after launch. In cooperation with a user group of 40+ state and local air quality forecasters, the system has been tested in real-time experiments where the results mimic what the forecasters will see after 2016 when GOES-R launches. Feedback from this group has allowed refinement of the web display system for the ABI aerosol products and has creatively called for new products that were not envisaged by the satellite team.

  2. Direct and Semi-direct Effects of Aerosol on the Climate System

    NASA Astrophysics Data System (ADS)

    Mahajan, S.; Evans, K. J.; Hack, J. J.; Truesdale, J.

    2011-12-01

    High-resolution (1x1 degree) global tropospheric aerosol datasets are generated using the atmospheric component of CESM1.0 coupled to an active bulk aerosol model for the 1850's and the period 1960-2000. The interactive aerosol module incorporates surface and elevated emissions of anthropogenic and natural aerosol precursors and oxidants. Experiments performed with the new aerosol datasets in atmosphere only GCM runs reveal that current level of aerosols can cause significant surface cooling and shift precipitation when compared to pre-industrial levels of aerosols. Experiments performed with the atmosphere component coupled to a slab ocean model reveal that aerosols can enhance the land-sea contrast, and cross-equatorial SST gradient leading to enhanced reduction in monsoon and shift in the ITCZ over the tropical Atlantic as compared to the atmosphere only runs. AMIP style experiments with the new aerosol dataset further reveal that aerosols could have had a significant impact on the trends in regional surface temperature and precipitation in the later part of the 20th century.

  3. Mexico City Aerosol Transect

    NASA Astrophysics Data System (ADS)

    Lewandowski, P. A.; Eichinger, W. E.; Prueger, J.; Holder, H. L.

    2007-12-01

    A radiative impact study was conducted in Mexico City during MILAGRO/MIRAGE campaign in March of 2006. On a day when the predominant wind was from the north to the south, authors measured radiative properties of the atmosphere in six locations across the city ranging from the city center, through the city south limits and the pass leading out of the city (causing pollutants to funnel through the area). A large change in aerosol optical properties has been noticed. The aerosol optical depth has generally increased outside of the city and angstrom coefficient has changed significantly towards smaller values. Aerosol size distribution was calculated using SkyRadPack. The total optical depths allowed coincidental lidar data to calculate total extinction profiles for all the locations for 1064nm.

  4. 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

  5. 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.

  6. Development and validation of an attenuated Mycoplasma hyopneumoniae aerosol vaccine.

    PubMed

    Feng, Zhi-Xin; Wei, Yan-Na; Li, Gui-Lan; Lu, Xiao-Ming; Wan, Xiu-Feng; Pharr, G Todd; Wang, Zhan-Wei; Kong, Meng; Gan, Yuan; Bai, Fang-Fang; Liu, Mao-Jun; Xiong, Qi-Yan; Wu, Xu-Su; Shao, Guo-Qing

    2013-12-27

    Mycoplasma hyopneumoniae (M. hyopneumoniae) causes a chronic respiratory disease with high morbidity and low mortality in swine, and has been presented as a major cause of growth retardation in the swine industry. Aerosol vaccination presents a needle free, high throughput, and efficient platform for vaccine delivery, and has been widely applied in poultry vaccination. However, aerosol vaccines have rarely been used in swine vaccination primarily because the long and curving respiratory track of swine presents a barrier for vaccine particle delivery. To develop an effective M. hyopneumoniae aerosol vaccine, three major barriers need to be overcome: to optimize particle size for aerosol delivery, to maintain the viability of mycoplasma cells in the vaccine, and to optimize the environmental conditions for vaccine delivery. In this study, an aerosol mycoplasma vaccine was successfully developed based on a conventional live attenuated M. hyopneumoniae vaccine. Specifically, the Pari LCD nebulizer was used to produce an aerosol vaccine particle size less than 5 μm; and a buffer with 5% glycerol was developed and optimized to prevent inactivation of M. hyopneumoniae caused by aerosolization and evaporation. Before nebulization, the room temperature and relative humidity were control to 20-25 °C and 70-75%, respectively, which helped maintain the viability of aerosol vaccine. Animal experiments demonstrated that this newly developed aerosol vaccine was effectively delivered to swine low respiratory track, being confirmed by nested-PCR, in situ hybridization and scanning electron microscope. Moreover, M. hyopneumoniae specific sIgA secretion was detected in the nasal swab samples at 14 days post-immunization. To our knowledge, this is the first report on a live M. hyopneumoniae aerosol vaccine. PMID:24035264

  7. 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

  8. 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.

  9. Highly stable aerosol generator

    DOEpatents

    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.

  10. 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.

  11. The physical state of UTLS aerosols

    NASA Astrophysics Data System (ADS)

    Peter, Th.; Colberg, C. A.; Corti, T.; Fueglistaler, S.; Hoyle, C. R.; Koop, T.; Krieger, U. K.; Luo, B. P.; Marcolli, C.

    2003-04-01

    This paper gives an overview of the present knowledge on the physical state of aerosols in the upper troposphere (UT) and lower stratosphere (LS). Are UTLS aerosols liquid, solid or mixed-phase? And how does ice nucleate in/on such aerosols? Good progress has been made towards a quantitative theory of homogeneous nucleation of ice in purely liquid solutions of arbitrary composition and concentration based on a volume-proportional description. Very recently it has been proposed that ice nucleation might be facilitated by the surface of aerosol droplets, rather than starting in the bulk, suggests a reversal of the traditional view. Nucleation rates would then be surface-proportional rather than volume-proportional, with potentially strong effects on cloud formation, ice number densities and dehydration of UT. However, laboratory and theoretical evidence is presented corroborating the traditional picture. Above the frost point UTLS aerosols remain either liquid or mixed-phase, e.g. solid letovicite plus the remaining liquid containing aqueous inorganic acids and organic compounds. Massive deliquescence and efflorescence point reductions are expected to occur upon mixing of miscible organic and inorganic components. Hence, for a reliable prediction of the phase composition of individual aerosol particles, the knowledge of the aerosol's mixing state is indispensable. By now little is known about the morphology of mixed-phase aerosols. Experiments suggest that the solid may be coated by liquid, or conversely that the liquid might be enclosed by the solid, possibly leading to different radiative and heterogeneous chemical properties. Knowledge on the impact of efflorescence or salting out on subsequent ice formation is at its infancy. The relative importance of all these processes, in particular of homogeneous and heterogeneous ice nucleation in the UTLS, depends crucially on gravity-wave-induced small-scale temperature fluctuations with typical amplitudes of 1-2 K and

  12. 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.

  13. MODIS Observation of Aerosols over Southern Africa During SAFARI 2000: Data, Validation, and Estimation of Aerosol Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles; Kaufman, Yoram; Remer, Lorraine; Chu, D. Allen; Mattoo, Shana; Tanre, Didier; Levy, Robert; Li, Rong-Rong; Kleidman, Richard; Lau, William K. M. (Technical Monitor)

    2001-01-01

    Aerosol properties, including optical thickness and size parameters, are retrieved operationally from the MODIS sensor onboard the Terra satellite launched on 18 December 1999. The predominant aerosol type over the Southern African region is smoke, which is generated from biomass burning on land and transported over the southern Atlantic Ocean. The SAFARI-2000 period experienced smoke aerosol emissions from the regular biomass burning activities as well as from the prescribed burns administered on the auspices of the experiment. The MODIS Aerosol Science Team (MAST) formulates and implements strategies for the retrieval of aerosol products from MODIS, as well as for validating and analyzing them in order to estimate aerosol effects in the radiative forcing of climate as accurately as possible. These activities are carried out not only from a global perspective, but also with a focus on specific regions identified as having interesting characteristics, such as the biomass burning phenomenon in southern Africa and the associated smoke aerosol, particulate, and trace gas emissions. Indeed, the SAFARI-2000 aerosol measurements from the ground and from aircraft, along with MODIS, provide excellent data sources for a more intensive validation and a closer study of the aerosol characteristics over Southern Africa. The SAFARI-2000 ground-based measurements of aerosol optical thickness (AOT) from both the automatic Aerosol Robotic Network (AERONET) and handheld Sun photometers have been used to validate MODIS retrievals, based on a sophisticated spatio-temporal technique. The average global monthly distribution of aerosol from MODIS has been combined with other data to calculate the southern African aerosol daily averaged (24 hr) radiative forcing over the ocean for September 2000. It is estimated that on the average, for cloud free conditions over an area of 9 million square kin, this predominantly smoke aerosol exerts a forcing of -30 W/square m C lose to the terrestrial

  14. Post-Pinatubo`s aerosols: Comparison between balloon and satellite solar occultation measurements

    SciTech Connect

    Brogniez, C.; Lenoble, J.; Herman, M.

    1995-12-31

    The Stratospheric Aerosol and Gas Experiment II (SAGE II), that was launched in October 1984, has monitored the stratospheric aerosol layer after the Pinatubo`s eruption. Two flights of the balloon-borne experiment RADIBAL (RADIometre BALlon) were performed in June 1992 and May 1993 in coincidence with SAGE II events. Because of the large aerosol loading, the inversion of the balloon measurements (consisting in radiance and polarization diagrams) was impracticable. A code taking into account the multiple scatterings has then been used to calculate theoretical diagrams for an aerosol model deduced from SAGE II data. The obtained diagrams have been compared satisfactorily to the experimental ones.

  15. 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.

  16. 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.

  17. 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. __________________________________________________

  18. Size-Resolved Volatility and Chemical Composition of Aged European Aerosol Measured During FAME-2008

    NASA Astrophysics Data System (ADS)

    Hildebrandt, L.; Mohr, C.; Lee, B.; Engelhart, G. J.; Decarlo, P. F.; Prevot, A. S.; Baltensperger, U.; Donahue, N. M.; Pandis, S. N.

    2008-12-01

    We present first results on the volatility and chemical composition of aged organic aerosol measured during the Finokalia Aerosol Measurement Experiment - 2008 (FAME-2008). Finokalia is located in the Southeast of Crete, Greece, and this remote site allows for the measurement of aged European aerosol as it is transported from Central to Southeastern Europe. We measured the volatility of the aerosol at Finokalia as a function of its size by combining several instruments. We used an Aerodyne quadrupole aerosol mass spectrometer (Q-AMS) to measure the size-resolved chemical composition of the particles, a scanning mobility particle sizer (SMPS) to measure the volume distribution of particles, and a thermodenuder system to induce changes in size and composition via moderate heating of the particles. The largest fraction of the non-refractory material in the aerosol sampled was ammonium sulfate and ammonium bisulfate, followed by organic material and a small contribution from nitrate. Most of the organic aerosol was highly oxidized, even after only a few days of transport over continental Europe. These highly oxidized organics had lower volatility than fresh primary or secondary aerosol measured in the laboratory. Significant changes in air-parcel trajectories and wind direction led to changes in the chemical composition of the sampled aerosol and corresponding changes of the volatility. These results allow the quantification of the effect of atmospheric processing on organic aerosol volatility and can be used as constraints for atmospheric Chemical Transport Models that predict the aerosol volatility.

  19. 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

  20. 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

  1. ACID AEROSOL MEASUREMENT WORKSHOP

    EPA Science Inventory

    This report documents the discussion and results of the U.S. EPA Acid Aerosol Measurement Workshop, conducted February 1-3, 1989, in Research Triangle Park, North Carolina. t was held in response to recommendations by the Clean Air Scientific Advisory Committee (CASAC) regarding ...

  2. EXPOSURES TO ACIDIC AEROSOLS

    EPA Science Inventory

    Ambient monitoring of acid aerosol in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. easurements made in Kingston, TN, and Stuebenville, OH, resulted in 24-hr H+ ion concentrations exceeding 100 nmole/m3 more than 10 ti...

  3. FORMATION OF PHOTOCHEMICAL AEROSOLS

    EPA Science Inventory

    The objective was to develop a better understanding of smog aerosol formation with particular reference to haze in the Southern California area. This study combined laboratory work with ambient air studies. Counting of particles by light scattering was the principle physical tech...

  4. Estimates of the Spectral Aerosol Single Sea Scattering Albedo and Aerosol Radiative Effects during SAFARI 2000

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.; Pilewskie, Peter; Schmid, Beat; Russell, Philip B.

    2003-01-01

    Using measurements of the spectral solar radiative flux and optical depth for 2 days (24 August and 6 September 2000) during the SAFARI 2000 intensive field experiment and a detailed radiative transfer model, we estimate the spectral single scattering albedo of the aerosol layer. The single scattering albedo is similar on the 2 days even though the optical depth for the aerosol layer was quite different. The aerosol single scattering albedo was between 0.85 and 0.90 at 350 nm, decreasing to 0.6 in the near infrared. The magnitude and decrease with wavelength of the single scattering albedo are consistent with the absorption properties of small black carbon particles. We estimate the uncertainty in the single scattering albedo due to the uncertainty in the measured fractional absorption and optical depths. The uncertainty in the single scattering albedo is significantly less on the high-optical-depth day (6 September) than on the low-optical-depth day (24 August). On the high-optical-depth day, the uncertainty in the single scattering albedo is 0.02 in the midvisible whereas on the low-optical-depth day the uncertainty is 0.08 in the midvisible. On both days, the uncertainty becomes larger in the near infrared. We compute the radiative effect of the aerosol by comparing calculations with and without the aerosol. The effect at the top of the atmosphere (TOA) is to cool the atmosphere by 13 W/sq m on 24 August and 17 W/sq m on 6 September. The effect on the downward flux at the surface is a reduction of 57 W/sq m on 24 August and 200 W/sq m on 6 September. The aerosol effect on the downward flux at the surface is in good agreement with the results reported from the Indian Ocean Experiment (INDOEX).

  5. Analysis and interpretation of lidar observations of the stratospheric aerosol

    NASA Technical Reports Server (NTRS)

    Hamill, P.; Swissler, T. J.; Osborn, M.; Mccormick, M. P.

    1980-01-01

    Data obtained with a 48 in. telescope lidar system are compared with results obtained using a one-dimensional stratospheric aerosol model to analyze various microphysical processes influencing the formation of this aerosol. Special attention is given to the following problems: (1) how lidar data can help determine the composition of the aerosol particles and (2) how the layer corresponds to temperature profile variations. The lidar record during the period 1974 to 1979 shows a considerable decrease of the peak value of the backscatter ratio. Seasonal variations in the aerosol layer and a gradual decrease in stratospheric loading are observed. The aerosol model simulates a background stratospheric aerosol layer, and it predicts stratospheric aerosol concentrations and compositions. Numerical experiments are carried out by using the model and by comparing the theoretical results with the experimentally obtained lidar record. Comparisons show that the backscatter profile is consistent with the composition when the particles are sulfuric acid and water; it is not consistent with an ammonium sulfate composition. It is shown that the backscatter ratio is not sensitive to the composition or stratospheric loading of condensation nuclei such as meteoritic debris.

  6. 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.

  7. Field Studies of Broadband Aerosol Optical Extinction in the Ultraviolet Spectral Region

    NASA Astrophysics Data System (ADS)

    Washenfelder, R. A.; Attwood, A.; Brock, C. A.; Brown, S. S.

    2013-12-01

    Aerosols influence the Earth's radiative budget by scattering and absorbing incoming solar radiation. The optical properties of aerosols vary as a function of wavelength, but few measurements have reported the wavelength dependence of aerosol extinction cross sections and complex refractive indices. In the case of brown carbon, its wavelength-dependent absorption in the ultraviolet spectral region has been suggested as an important component of aerosol radiative forcing. We describe a new field instrument to measure aerosol optical extinction as a function of wavelength, using cavity enhanced spectroscopy with a broadband light source. The instrument consists of two broadband channels which span the 360-390 and 385-420 nm spectral regions using two light emitting diodes (LED) and a grating spectrometer with charge-coupled device (CCD) detector. We deployed this instrument during the Fire Lab at Missoula Experiment during Fall 2012 to measure biomass burning aerosol, and again during the Southern Oxidant and Aerosol Study in summer 2013 to measure organic aerosol in the Southeastern U.S. In both field experiments, we determined aerosol optical extinction as a function of wavelength and can interpret this together with size distribution and composition measurements to characterize the aerosol optical properties and radiative forcing.

  8. 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.

  9. 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.

  10. Laboratory and field measurements of organic aerosols with the photoionization aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Dreyfus, Matthew A.

    Analytical methods developed to sample and characterize ambient organic aerosols often face the trade-off between long sampling times and the loss of detailed information regarding specific chemical species present. The soft, universal ionization scheme of the Photoionization Aerosol Mass Spectrometer (PIAMS) allows for identification of various chemical compounds by a signature ion, often the molecular ion. The goal of this thesis work is to apply PIAMS to both laboratory and field experiments to answer questions regarding the formation, composition, and behavior of organic aerosols. To achieve this goal, a variety of hardware and software upgrades were administered to PIAMS to optimize the instrument. Data collection and processing software were either refined or built from the ground up to simplify difficult or monotonous tasks. Additional components were added to PIAMS with the intent to automate the instrument, enhance the results, and make the instrument more rugged and user-friendly. These changes, combined with the application of an external particle concentration system (mini-Versatile Aerosol Concentration Enrichment System, m-VACES), allowed PIAMS to be suitable for field measurements of organic aerosols. Two such field campaigns were completed, both at the State of Delaware Air Quality Monitoring Site in Wilmington, Delaware: a one week period in June, 2006, and an 18 day period in October and November of 2007. A sampling method developed was capable of collecting sufficient ambient organic aerosol and analyzing it with a time resolution of 3.5 minutes. Because of this method, short term concentration changes of individual species can be tracked. Combined with meteorological data, the behavior of these species can be analyzed as a function of time or wind direction. Many compounds are found at enhanced levels during the evening/night-time hours; potentially due to the combined effects of temperature inversion, and fresh emissions in a cooler environment

  11. Oxodicarboxylic acids in atmospheric aerosol particles

    NASA Astrophysics Data System (ADS)

    Römpp, Andreas; Winterhalter, Richard; Moortgat, Geert K.

    Fine mode aerosol was collected on quartz fiber filters at several sites across Europe. These samples were analyzed for carboxylic acids by liquid chromatography coupled to a hybrid (quadrupole and time-of-flight) mass spectrometer (LC/MS/MS-TOF). A series of oxodicarboxylic acids (C 7-C 11) was detected. Oxodicarboxylic acids are linear dicarboxylic acids with an additional carbonyl group. Previous measurements of these acids are scarce and their sources are largely unknown. Several structural isomers (different positions of the carbonyl group within the molecule) could be identified and differentiated by the combination of laboratory experiments and high mass accuracy measurements. The homologs with 9-11 carbon atoms were identified for the first time in atmospheric aerosol particles. The concentrations of oxodicarboxylic acids in ambient aerosol samples frequently exceeded those of the corresponding unsubstituted dicarboxylic acids. Oxodicarboxylic acids have been shown to be products of the reaction of dicarboxylic acids with OH radicals in chamber experiments and a reaction mechanism is proposed. Good correlation of oxodicarboxylic acid and hydroxyl radical concentrations was found at two measurement sites (Finland and Crete) of different geographic location and meteorological conditions. The ratios of individual isomers from the field samples are comparable to those of the laboratory experiments. The results of this study imply that the reaction of OH radicals and dicarboxylic acids is an important pathway for the production of oxodicarboxylic acids in the atmosphere. Oxodicarboxylic acids seem to be important intermediates in atmospheric oxidation processes of organic compounds.

  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. 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.

  14. 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.

  15. 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

  16. 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.

  17. Impacts of Aminium Sulfates on Atmospheric Aerosol Properties

    NASA Astrophysics Data System (ADS)

    Qiu, C.; Zhang, R.

    2012-12-01

    Atmospheric aerosols influence our environment significantly by interacting with the solar radiation and modifying cloud formation processes. Amines are emitted into the atmosphere from various anthropogenic and biogenic sources. Recent studies have shown that atmospheric amines can enter the particle-phase as salts like aminium sulfates by reacting with aerosol constituents including sulfuric acid and ammonium salts. However, little knowledge is available about the properties of these aminium salts and their impacts on aerosol properties. We have conducted laboratory experiments to measure the hygroscopicity, thermostability, and density of five representative alkylaminium sulfates, using an integrated aerosol analytical system including a tandem differential mobility analyzer and an aerosol particle mass analyzer. When exposed to increasing RH, alkylaminium sulfate aerosols show monotonic growth in size without a well-defined deliquescence point. Aerosols of mixed ammonium-alkylaminium sulfates have deliquescence points lower than that of ammonium sulfate. The measurements of thermostability reveal that dimethylaminium sulfate is the most stable species upon heating. Trimethyl- and triethyl-aminium sulfates volatilize similarly to ammonium sulfate, but exhibit lower volatility than monomethyl- and diethyl-aminium sulfates. The density of alkylaminium sulfates ranges from 1.2 to 1.5 g cm-3, and can be predicted from an empirical model on the basis of the mole ratio of alkyl carbons to total sulfate. Our results suggest that the properties of aerosols may be considerably altered by the incorporation of atmospheric amines through heterogeneous reactions. In particular, these processes may lead to an enhanced water uptake at low RH and considerably change the contribution of aerosols to climate forcing.

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. Numerical calculation of aerosol transmittance on transmission route

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Xie, Xiao-fang

    2015-02-01

    The aerosol transmittance on the transmission route can not be ignored in atmosphere transmittance calculation. The classical mathematic models at present just calculate the vertical transmittance. MODTRAN is a good choice, but it is difficult called in users own project. In this paper, we build a model of the vertical transmittance for aerosol patterns by exponential regression analysis, and calculate aerosol transmittance on slant route by the simple mathematical relationship of vertical transmittance and horizontal transmittance. In this way, the aerosol transmittance on common route can be calculated just by the altitude of detector and slant angle of the route. We suggest the method in this paper can be easily used for the calculation in users project of real-time infrared simulation of missile-borne or airborne detector. According to the experiments, the average residuals of transmittance on slant route is less than 0.0005, while that on horizontal route is less than 0.0003.

  4. 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

  5. Rethinking organic aerosols: semivolatile emissions and photochemical aging.

    PubMed

    Robinson, Allen L; Donahue, Neil M; Shrivastava, Manish K; Weitkamp, Emily A; Sage, Amy M; Grieshop, Andrew P; Lane, Timothy E; Pierce, Jeffrey R; Pandis, Spyros N

    2007-03-01

    Most primary organic-particulate emissions are semivolatile; thus, they partially evaporate with atmospheric dilution, creating substantial amounts of low-volatility gas-phase material. Laboratory experiments show that photo-oxidation of diesel emissions rapidly generates organic aerosol, greatly exceeding the contribution from known secondary organic-aerosol precursors. We attribute this unexplained secondary organic-aerosol production to the oxidation of low-volatility gas-phase species. Accounting for partitioning and photochemical processing of primary emissions creates a more regionally distributed aerosol and brings model predictions into better agreement with observations. Controlling organic particulate-matter concentrations will require substantial changes in the approaches that are currently used to measure and regulate emissions. PMID:17332409

  6. 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.

  7. 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...

  8. 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%.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Using a laser aureole to study aerosols

    NASA Astrophysics Data System (ADS)

    Long, Brandon J. N.; Hook, D. A.; Pangle, Garrett E.; Hallen, Hans D.; Philbrick, C. R.

    2013-05-01

    Aerosol optical scattering experiments are often large, expensive, and provide poor control of dust uniformity and size distribution. The size distribution of such suspended atmospheric aerosols varies rapidly in time, since larger particles settle quickly. Even in large chambers, 10 micron particles settle in tens of seconds. We describe lab-scale experiments with stable particle distributions. A viscous colloidal solution can stabilize the particles for sufficient time to measure optical scattering properties. Colloids with different concentrations or size distributions enable nearly time independent studies of prepared distributions. We perform laser aureole scattering from a colloid containing a few percent by volume of Arizona Road Dust (ARD) in mineral oil and glycerin, and 1-micron polystyrene spheres in water. We discuss aureole analysis, the differences expected in scattering properties due to the index of refraction of the mineral oil medium versus air, and the impact of non-spherical shape on the scattering. This research demonstrates that particles suspended in a viscous medium can be used to simulate aerosol optical scattering in air, while enabling signal averaging, offering reproducibility, and easing problems resulting from parameter variations in studies of dust properties.

  15. Assimilation of Aerosol Optical Depths

    NASA Astrophysics Data System (ADS)

    Verver, Gé; Henzing, Bas

    Climate predictions are hampered by the large uncertainties involved in the estima- tion of the effects of atmospheric aerosol (IPCC,2001). These uncertainties are caused partly because sources and sinks as well as atmospheric processing of the different types of aerosol are not accurately known. Moreover, the climate impact (especially the indirect effect) of a certain distribution of aerosol is hard to quantify. There have been different approaches to reduce these uncertainties. In recent years intensive ob- servational campaigns such as ACE and INDOEX have been carried out, aiming to in- crease our knowledge of atmospheric processes that determine the fate of atmospheric aerosols and to quantify the radiation effects. With the new satellite instruments such as SCIAMACHY and OMI it will be possible in the near future to derive the ge- ographical distribution of the aerosol optical depths (AOD) and perhaps additional information on the occurrence of different aerosol types. The goal of the ARIA project (started in 2001) is to assimilate global satellite de- rived aerosol optical depth (AOD) in an off-line chemistry/transport model TM3. The TM3 model (Jeuken et al. 2001) describes sources, sinks, transformation and transport processes of different types of aerosol (mineral dust, carbon, sulfate, nitrate) that are relevant to radiative forcing. All meteorological input is provided by ECMWF. The assimilation procedure constrains the aerosol distribution produced by the model on the basis of aerosol optical depths observed by satellite. The product, i.e. an optimal estimation of global aerosol distribution, is then available for the calculation of radia- tive forcing. Error analyses may provide valuable information on deficiencies of the model. In the ARIA project it is tried to extract additional information on the type of aerosol present in the atmosphere by assimilating AOD at multiple wavelengths. First results of the ARIA project will be presented. The values

  16. Vertical profiles of aerosol radiative forcing - a comparison of AEROCOM phase 2 model submissions

    NASA Astrophysics Data System (ADS)

    Samset, B. H.; Myhre, G.

    2012-04-01

    Aerosols in the earth's atmosphere affect the radiation balance of the planet. The radiative forcing (RF) induced by a given aerosol burden is however sensitive to its vertical density profile, in addition to aerosol optical properties, cloud distributions and surface albedo. Differences in vertical profiles are thought to be among the causes for the large intermodel differences in RF of the aerosol direct effect. As part of the AEROCOM phase 2 direct radiative forcing experiment, this study compares 3D concentration fields of black carbon from fossil fuel burning (BC) and sulphate (SO4) from a set of major global climate models. The participating models were run using a prescribed set of emissions of aerosol and aerosol precursors and the same meteorological year. We assume that model differences due to the aerosol vertical profile can be factored out from other differences such as aerosol physics, radiative transfer or ground albedo. We consequently analyse model RF variability using profiles of normalized RF (radiative forcing per unit mass, NDRF) calculated from a single model. This tool allows us to quantify the fraction of the intermodel variability due to differences in aerosol vertical profiles. We show that there are still significant differences between both modelled vertical density profiles, treatment of aerosol physics and other factors influencing the RF profiles.

  17. 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.

  18. 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