Science.gov

Sample records for aerosol measurement experiment

  1. Aerosol size distribution and aerosol water content measurements during Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Sievering, H.; Boatman, J.; Wellman, D.; Pszenny, A.

    1995-11-01

    Aerosol size distribution data measured during the June 1992 Marine Aerosol and Gas Exchange experiment are analyzed to investigate the characteristics of fine marine aerosol particles measured over the North Atlantic near the Azores Islands. Measured aerosol size distribution data were corrected using the corrected size calibration data based on the optical properties of particles being measured. The corrected size distribution data were then approximated with either one or two lognormal size distributions, depending on air mass conditions. Under clean air mass conditions <3 μm diameter aerosol size distributions typically exhibited two modes, consisting of an accumulation mode and the small end of the sea-salt particle mode. However, under the influence of continental polluted air masses, the aerosol size distribution was dominated by <1 μm diameter particles in a single mode with an increased aerosol concentration. Aerosol water content of accumulation mode marine aerosols was estimated from differences between several series of ambient and dried aerosol size distributions. The average aerosol water fraction was 0.31, which is in good agreement with an empirical aerosol growth model estimate. The average rate of SO4= production in the accumulation mode aerosol water by H2O2 oxidation was estimated to be <7×10-10 mol L-1 s-1, which is an insignificant contributor to the observed non-sea-salt SO4= in the accumulation mode.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Ganges valley aerosol experiment.

    SciTech Connect

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

    2011-08-01

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

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. CO, O3, and aerosol measurements from NASA Global Tropospheric Experiment - Test flights 1981

    NASA Astrophysics Data System (ADS)

    Hinton, R. R.; Browell, E. V.; Gregory, G. L.; Harriss, R. C.

    1982-05-01

    A series of four instrument test flights was conducted during July 1981 in preparation for the NASA Global Tropospheric Experiment. The purpose of the flights was to demonstrate the feasibility and value of simultaneously measuring several specific atmospheric pollutants over a 25 deg latitudinal range. Carbon monoxide and methane grab samples were obtained simultaneously with nearly continuous in situ ozone and remote ozone and aerosol optical radar measurements. The sampling platform was a NASA Electra, a four engine turboprop aircraft. Attention is given to CO and CH4 sample collection and analysis, ozone measurement methods, the aerosol measurement method, an interpretation of the optical radar display, and a synergistic consideration of results.

  12. Aerosol Characteristics during the CLAMS Experiment: in situ and Remote Sensing Measurements

    NASA Astrophysics Data System (ADS)

    Martins, J.; Remer, L.; Castanho, A.; Kaufman, Y.; Artaxo, P.; Mattoo, S.; Levy, R.; Kleidman, R.; Hobbs, P. V.; Plana-Fattori, A.; Yamasoe, M.; Redemann, J.

    2002-05-01

    Remote sensing measurements of aerosol properties were performed with MODIS on the Terra satellite, and with the MAS (MODIS Airborne Simulator) on the ER-2 aircraft during the CLAMS experiment. Remote sensing measurements were validated and complemented by in situ observations. MODIS measurements were operationally obtained over the dark ocean and were explored experimentally over the sun glint. During the experiment, MODIS results indicated episodes of long range transport of large aerosol particles over the CLAMS region. These particles were also identified in the in situ aerosol measurements and by aeronet size distributions. In situ aerosol measurements were performed aboard the University of Washington's Convair-580 Research Aircraft, on the Cheasapeake Lighthouse (about 25km from the coast), and on Wallops Island. Spectral absorption measurements performed on Nuclepore filters showed relatively low absorption efficiencies (about 0.21+/-0.08m2/g at 0.55um and 0.052+/-0.023m2/g at 2.1um at the Wallops Island station) and a spectral dependence close to 1/lambda or stronger. The spectral absorption shows characteristics of small black carbon (BC) particles (spectral dependence around 1/lambda) and soil dust-like particles (stronger absorption in the blue). Electron Microscopy pictures show cluster aggregates typically composed by black carbon particles and medium to large dust-like particles. The elemental composition of the particles measured on the Nuclepore filters also indicated the presence of dust-like particles on certain days of the experiment. The average absorption efficiency found in the area was significantly lower (by about one order of magnitude) than the absorption efficiency of biomass burning particles or urban pollution from developing countries. The complementarities of remote sensing and in situ measurements in the interpretation of the aerosol over the region will be discussed and explored.

  13. 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.

  14. 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.

  15. 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...

  16. A global climatology of stratospheric aerosol surface area density deduced from Stratospheric Aerosol and Gas Experiment II measurements: 1984-1994

    NASA Astrophysics Data System (ADS)

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

    1997-04-01

    A global climatology of stratospheric aerosol surface area density has been developed using the multiwavelength aerosol extinction measurements of the Stratospheric Aerosol and Gas Experiment (SAGE) II for 1984-1994. The spatial and temporal variability of aerosol surface area density at 15.5, 20.5, and 25.5 km are presented as well as cumulative statistical distributions as a function of altitude and latitude. During this period, which encompassed the injection and dissipation of the aerosol associated with the June 1991 Mount Pinatubo eruption as well as the low loading period of 1989-1991, aerosol surface area density varied by more than a factor 30 at some altitudes. Aerosol surface area density derived from SAGE II and from the University of Wyoming optical particle counters are compared for 1991-1994 and are shown to be in generally good agreement though some differences are noted. An extension of the climatology using single-wavelength measurements by the Stratospheric Aerosol Measurement II (1978-1994) and SAGE (1979-1981) instruments is also presented.

  17. Stratospheric Aerosol Measurements

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  18. 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.

  19. 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.

  20. 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.

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

    SciTech Connect

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

    2005-06-20

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

  2. 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.

  3. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  5. 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.

  6. Airborne measurements of aerosols from burning biomass in Brazil related to the TRACE A experiment

    NASA Astrophysics Data System (ADS)

    Pereira, E. B.; Setzer, A. W.; Gerab, F.; Artaxo, P. E.; Pereira, M. C.; Monroe, G.

    1996-10-01

    Results are reported from an airborne campaign to investigate the impacts of burning biomass upon the loading of lower-tropospheric aerosols and its composition over the Brazilian tropics. The flights, conducted as part of the NASA/Transport and Atmospheric Chemistry Near the Equator-Atlantic (TRACE A) mission, started on September 1, 1992, when the dry (fire) season still prevailed in the central part of Brazil, and ended on September 29. Of the total number of burnings detected in Brazil by the advanced very high resolution radiometer (AVHRR)/NOAA satellite sensor, 74% were concentrated in the states of Amazonas, Maranhão, Mato Grosso, Pará, Roraima, and Tocantins during this period. Aerosol particles were sampled from a twin-engine aircraft in transit and vertical profile flights were made up to 4,000 m altitude. Black carbon measurements made in real time and in areas of burning biomass peaked at ˜2,500 m above the ground, increasing to ˜12,000 ng/m3. In other areas these values were lower by 1 order of magnitude. A condensation nuclei counter measuring small particles (>0.014 μm) produced values ranging from 2,000 to 16,000/cm3 for areas with low and high burning biomass, respectively. Deposition filters in a two-stage cascade impactor, and Nuclepore filters collected aerosols for analysis of 13 elements through particle-induced X ray emissions (PIXE). Primary elements associated with soil dust (Al, Si, Mn, Fe, Ni) prevailed in the aerosol coarse mode (>1 μm) while the fine mode aerosols were enriched in S, K, Br, and Rb, which are tracers normally associated with burning of biomass. The good correlation between fire spot counts, obtained via AVHRR aboard NOAA satellites, and black carbon, counts of small particles and total aerosol mass, suggests the determining of local concentrations of fire-derived aerosol fire emissions by satellite to be a new and useful approach.

  7. Urban aerosol radiative properties: Measurements during the 1999 Atlanta Supersite Experiment

    NASA Astrophysics Data System (ADS)

    Carrico, Christian M.; Bergin, Michael H.; Xu, Jin; Baumann, Karsten; Maring, Hal

    2003-04-01

    As part of the Atlanta Supersite 1999 study, aerosol radiative and related physical and chemical properties are examined on the basis of measurements of PM2.5 (aerosol particles with aerodynamic diameters, Dp, less than 2.5 μm) in urban Atlanta. In addition to potential compliance issues with proposed regulatory standards, PM2.5 concentrations in Atlanta and the surrounding region are large enough to have an important impact on atmospheric radiative transfer and hence visibility and potentially regional climate. Arithmetic means and standard deviations of the light scattering by PM2.5 (σsp at 530 nm) and absorption coefficients (σap at 550 nm) measured at a controlled relative humidity of 49 ± 5% are 121 ± 48 and 16 ± 12 Mm-1, respectively. Though the mean light extinction coefficient (σep) in Atlanta is much larger than background sites, it is comparable to nonurban areas in the interior southeast United States highlighting the contribution of a regional haze here. The single scattering albedo (ωo) in Atlanta is 0.87 ± 0.08 and is ˜10% lower than reported in nonurban polluted sites, likely a result of the emission of elemental carbon (EC) from mobile sources. A pronounced diel pattern in aerosol properties is observed with clear influences from mobile sources (morning rush hour maxima in concentrations, particularly soot-related indicators) and atmospheric mixing (afternoon minima). A strong linear relationship between σsp and PM2.5 is observed, and using several techniques, gives a range of mean mass scattering efficiencies (Esp) from = 3.5 to 4.4 m2 g-1. EC and σap are observed to have a relationship though less strongly correlated than σsp and PM2.5. Four methods of determining the mass absorption efficiency of EC give Eap ranging from 5.3 to 18.3 m2 g-1. This wide range of values is a result of the variability in aerosol properties, uncertainties in the light absorption method, and in particular, differences in the EC measurement techniques. Best

  8. NASA's Aerosol Sampling Experiment Summary

    NASA Technical Reports Server (NTRS)

    Meyer, Marit E.

    2016-01-01

    In a spacecraft cabin environment, the size range of indoor aerosols is much larger and they persist longer than on Earth because they are not removed by gravitational settling. A previous aerosol experiment in 1991 documented that over 90 of the mass concentration of particles in the NASA Space Shuttle air were between 10 m and 100 m based on measurements with a multi-stage virtual impactor and a nephelometer (Liu et al. 1991). While the now-retired Space Shuttle had short duration missions (less than two weeks), the International Space Station (ISS) has been continually inhabited by astronauts for over a decade. High concentrations of inhalable particles on ISS are potentially responsible for crew complaints of respiratory and eye irritation and comments about 'dusty' air. Air filtration is the current control strategy for airborne particles on the ISS, and filtration modeling, performed for engineering and design validation of the air revitalization system in ISS, predicted that PM requirements would be met. However, aerosol monitoring has never been performed on the ISS to verify PM levels. A flight experiment is in preparation which will provide data on particulate matter in ISS ambient air. Particles will be collected with a thermophoretic sampler as well as with passive samplers which will extend the particle size range of sampling. Samples will be returned to Earth for chemical and microscopic analyses, providing the first aerosol data for ISS ambient air.

  9. 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.

  10. Measurement of Organic and Inorganic Chemical Tracers for Source Apportionment of Tropospheric Aerosols Collected During the ACE-Asia Experiment

    NASA Astrophysics Data System (ADS)

    Schauer, J. J.; Park, J.; Duvall, R.; Bae, M.; Shafer, M. M.; Chuang, P.; Chuang, P.; Kim, Y. J.

    2001-12-01

    Naturally occurring dust and anthropogenic air pollutants are important contributors to tropospheric aerosols and impact air quality and the radiative balance of the Earth's atmosphere. In order to better understand the relationship between the origin, chemical composition and ultimate impact of Asian aerosols on climate forcing, aerosol samples were collected as part of the ACE-Asia experiment for detailed chemical analysis. Atmospheric particulate matter samples were collected from March 27, 2001 through May 6, 2001 at the ACE-Asia ground station located on Cheju Island, Korea. During this period, this region is impacted by anthropogenic air pollution emissions from highly urbanized region of Asia and by desert dust originating from northeastern Asia. As part of the experiment, atmospheric particulate matter samplers were also collected in urban and desert locations in Asia that represent regional sources of particulate matter in Asia. Size resolved aerosol samples were analyzed for trace metals by using microwave assisted-acid digestion and ICP-MS analysis, speciated organic compounds using solvent extraction and GC-MS analysis, as well as soluble ions and elemental and organic carbon (ECOC). These measurements provide fingerprints for source apportionment of the atmospheric particulate matter samples collected at the Cheju Island sampling site. The use of these chemical tracers for apportionment of wind-driven long range transported desert dust, local crustal derived dust, biogenically and anthropogenically derived sulfate, specific urban combustion source, and fossil fuel combustion will be presented.

  11. 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

  12. 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.

  13. Aerosol light absorption measurements during the Reno Aerosol Optics Experiment: Photoacoustic measurements and a multiple-scattering model for the aethalometer response.

    NASA Astrophysics Data System (ADS)

    Arnott, W. P.; Moosmueller, H.; Sheridan, P. J.; Ogren, J. A.

    2002-12-01

    The filter used on the aethalometer is a multiple scattering substrate, yet the current parameterization of the instrument simply uses Beer's law for its analysis when obtaining black carbon concentration. Specific characterizations of the instrument response, where filter attenuation was obtained as a function of wavelength, gave the following impressions. 1. Filter attenuation generally increases inversely with wavelength for all aerosol types. 2. When subjected to a constant flow of low single scattering albedo aerosol, the instrument shows a non-constant response. The response is highest when the filter single scattering albdeo is highest, and it decreases as the filter blackens. 3. When subjected to a constant flow of essentially unity single scattering albedo aerosol, the instrument shows a non-zero response, even though it should do so. A few percent of scattering is converted to absorption, because the addition of purely scattering aerosol is analogous to a simple thickening of the filter. The effect is more pronounced at shorter wavelengths, and is related to item 1. The multiple scattering model reproduces these behaviors. The photoacoustic instrument light absorption calibration with nitrogen dioxide gas will be presented along with closure data from extinction minus scattering as evaluations of its measurement accuracy.

  14. Retrieval of aerosol complex refractive index from a synergy between lidar, sunphotometer and in situ measurements during LISAIR experiment

    NASA Astrophysics Data System (ADS)

    Raut, J.-C.; Chazette, P.

    2007-06-01

    Particulate pollutant exchanges between the streets and the Planetary Boundary Layer (PBL), and their daily evolution linked to human activity were studied in the framework of the LIdar pour la Surveillance de l'AIR (LISAIR) experiment. This program lasted from 10 to 30 May 2005. A synergetic approach combining dedicated active (lidar) and passive (sunphotometer) remote sensors as well as ground based in situ instrumentation (nephelometer, aethalometer and particle sizers) was used to investigate urban aerosol optical properties within Paris. Aerosol complex refractive indices were assessed to be 1.56-0.034 i at 355 nm and 1.59-0.040 i at 532 nm, thus leading to single-scattering albedo values between 0.80 and 0.88. These retrievals are consistent with soot components in the aerosol arising from traffic exhausts indicating that these pollutants have a radiative impact on climate. We also discussed the influence of relative humidity on aerosol properties. A good agreement was found between vertical extinction profile derived from lidar backscattering signal and retrieved from the coupling between radiosounding and ground in situ measurements.

  15. Retrieval of aerosol complex refractive index from a synergy between lidar, sunphotometer and in situ measurements during LISAIR experiment

    NASA Astrophysics Data System (ADS)

    Raut, J.-C.; Chazette, P.

    2007-01-01

    Particulate pollutant exchanges between the streets and the Planetary Boundary Layer (PBL), and their daily evolution linked to human activity were studied in the framework of the LIdar pour la Surveillance de l'AIR (LISAIR) experiment. This program lasted from 10 to 30 May 2005. A synergetic approach combining dedicated active (lidar) and passive (sunphotometer) remote sensors as well as ground based in situ instrumentation (nephelometer, aethalometer and particle sizers) was used to investigate urban aerosol optical properties within Paris. Aerosol complex refractive indices were assessed to be 1.56-0.034i at 355 nm and 1.59-0.040i at 532 nm, thus leading to single-scattering albedo values between 0.80 and 0.88. These retrievals are consistent with soot components in the aerosol arising from traffic exhausts indicating that these pollutants have a radiative impact on climate. We also discussed the influence of relative humidity on aerosol properties. A good agreement was found between vertical extinction profile derived from lidar backscattering signal and retrieved from the coupling between radiosounding and ground in situ measurements.

  16. 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).

  17. Combining Suborbital Measurements of Aerosol Optical Depth and Columnar Water Vapor for Satellite Sensor Validations in the CLAMS (Chesapeake Lighthouse and Aircraft Measurements for Satellites) Experiment, 2001

    NASA Astrophysics Data System (ADS)

    Redemann, J.; Schmid, B.; Livingston, J. M.; Russell, P. B.; Eilers, J. A.; Hobbs, P. V.; Kahn, R.; Smith, W. L.; Holben, B. N.; Rutledge, C. K.; Pitts, M. C.; Mishchenko, M. I.; Chowdhary, J.; Martins, J. V.; Plana-Fattori, A.; Charlock, T. P.

    2002-05-01

    As part of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment, July 10 - August 2, 2001, the 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was operated successfully aboard the University of Washington Convair-580 during 10 research flights (~45 flight hours). The CLAMS campaign was a clear sky, shortwave (SW) closure campaign that entailed measurements from the Chesapeake Lighthouse research platform, several land sites, 6 research aircraft and the Terra satellite. CLAMS research goals included validation of satellite-based retrievals of aerosol properties, vertical profiles of radiative fluxes, temperature and water vapor. Suborbital measurements of aerosol optical depth (AOD) and columnar water vapor (CWV) were carried out at several AERONET sites and aboard five of the six airborne platforms using a variety of techniques. AATS-14 measures the direct solar beam transmission at 14 discrete wavelengths (354-1558 nm), yielding aerosol optical depth spectra and columnar water vapor. During coordinated flights of the UW Convair-580, AATS-14 measured full column aerosol optical depth spectra at exact Terra overpass time on at least 7 occasions. For five of these opportunities, AOD at 499nm was at or below 0.1. During Terra overpass on July 17, 2001, AATS-14 measured the largest AOD encountered during the entire experiment (~0.48 at 499nm), including a horizontal gradient in AOD of more than 0.1 over a distance of ~80 kilometers. We will illustrate how the spatially resolved measurements by AATS-14 and the temporally resolved AERONET measurements can be usefully combined for satellite validation purposes by constraining the small-scale aerosol variability off the US East coast. While the first part of this paper is focused on AATS-14 measurements, in the remainder of this paper we will show comparisons to other suborbital measurements obtained using (i) the AERONET sun/sky radiometer at the Chesapeake Lighthouse, (ii

  18. 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.

  19. 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

  20. Experience of direct impactor measurements of the structure and composition of stratospheric aerosols in polar latitudes

    NASA Astrophysics Data System (ADS)

    Kondratyev, K. Y.; Ivlev, Leo S.; Ivanov, V. A.; Zhukov, V. M.

    1993-11-01

    The data obtained in 1989 during the launchings to the stratosphere of a two-cascade impactor from the test ground in Apatity have been discussed. The aerosol samples have been analyzed using an electronic microscope to have information on the structure and size distribution of aerosol particles. The chemical and elemental analyses have been made using the methods of mass-spectrometry, IR spectroscopy, neutron activation, and x-ray fluorescence.

  1. Cavity Ring-Down Measurement of Aerosol Optical Properties During the Asian Dust Above Monterey Experiment and DOE Aerosol Intensive Operating Period

    NASA Technical Reports Server (NTRS)

    Ricci, K.; Strawa, A. W.; Provencal, R.; Castaneda, R.; Bucholtz, A.; Schmid, B.

    2004-01-01

    Large uncertainties in the effects of aerosols on climate require improved in-situ measurements of extinction coefficient and single-scattering albedo. This paper describes preliminary results from Cadenza, a new continuous wave cavity ring-down (CW-CRD) instrument designed to address these uncertainties. Cadenza measures the aerosol extinction coefficient for 675 nm and 1550 nm light, and simultaneously measures the scattering coefficient at 675 nm. In the past year Cadenza was deployed in the Asian Dust Above Monterey (ADAM) and DOE Aerosol Intensive Operating Period (IOP) field projects. During these flights Cadenza produced measurements of aerosol extinction in the range from 0.2 to 300/Mm with an estimated precision of 0.1/Mm for 1550 nm light and 0.2/Mm for 675 nm light. Cadenza data from the ADAM and Aerosol IOP missions compared favorably with data from the other instruments aboard the CIRPAS Twin Otter aircraft and participating in those projects. We present comparisons between the Cadenza measurements and those from a TSI nephelometer, Particle Soot Absorption Photometer (PSAP), and the AATS 14 sun-photometer. Measurements of the optical properties of smoke and dust plumes sampled during these campaigns are presented and estimates of heating rates due to these plumes are made.

  2. 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

  3. Airborne Sun photometer measurements of aerosol optical depth and columnar water vapor during the Puerto Rico Dust Experiment and comparison with land, aircraft, and satellite measurements

    NASA Astrophysics Data System (ADS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey S.; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Smirnov, Alexander; Dubovik, Oleg; Welton, Ellsworth J.; Campbell, James R.; Wang, Jun; Christopher, Sundar A.

    2003-10-01

    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 above sea level (asl) reproduce the vertical structure measured by coincident aircraft in situ measurements of total aerosol number concentration. AATS-6 extinction retrievals also agree with corresponding values derived from ground-based lidar measurements for altitudes above the trade inversion. The spectral behavior of AOD within specific layers beneath the top of the aircraft profile is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt, with mean Ångström wavelength exponents of ˜0.20. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in situ measurements agree to within ˜4% (0.13 g/cm2). 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 0.004-0.030 with coincident data obtained with an AERONET Sun/sky radiometer located on Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by ˜21%. AATS-6 AOD values measured during low-altitude aircraft traverses over the ocean are compared with corresponding AOD values retrieved over water from upwelling radiance measurements by the Moderate-Resolution Imaging Spectroradiometer (MODIS), Total Ozone Mapping Spectrometer (TOMS), and GOES 8 Imager satellite sensors, with mixed results.

  4. Comparisons between Stratospheric Aerosol and Gas Experiment II and microwave limb sounder ozone measurements and aliasing of SAGE II ozone trends in the lower stratosphere

    NASA Astrophysics Data System (ADS)

    Cunnold, D. M.; Wang, H.; Chu, W. P.; Froidevaux, L.

    1996-04-01

    SAGE II ozone measurements are compared with coincident microwave limb sounder (MLS) measurements over the period September 1991 to December 1993. Between 1.5 and 10 mbar the MLS ozone values are approximately 5% larger than the Stratospheric Aerosol and Gas Experiment (SAGE) II values. These differences are remarkably systematic in space and time. At 1 mbar the mean differences are zero and the mean differences oscillate with level at lower pressures. A month of comparisons against Halogen Occultation Experiment ozone measurements suggests that the differences at pressures less than 1.5 mbar are a feature of the MLS measurements. There are also differences between SAGE II sunrise and sunset measurements at 1 mbar which may be associated with the diurnal tide. At pressures greater than 10 mbar the comparisons indicate that the SAGE II ozone retrievals are being biased by the large aerosol concentrations resulting from the Mount Pinatubo eruption. For a fixed aerosol extinction the SAGE II/MLS difference (ppm) is larger at higher altitudes. It also depends nonlinearly on the aerosol extinction at pressures greater than 20 mbar. These effects are probably caused by the interpolation of the SAGE II aerosol extinction to 0.6 μm and by the evolution of the aerosol size distribution. For UARS layer aerosol optical depths less than 2 × 10-3 at 1.02 μm, the aerosol effect on the SAGE II ozone retrievals is inferred to be 3 × 1010 cm-3/10-3 aerosol layer optical depth at pressures greater than 20 mbar. This is equivalent to approximately 3% of the aerosol extinction at 0.6 μm being interpreted as ozone. At low aerosol concentrations and between 10 and 31 mbar, MLS ozone values are found to be approximately 5% larger than SAGE II ozone values (in agreement with the higher-altitude differences). Atmospheric aerosol concentrations prior to the Mount Pinatubo eruption were large enough, particularly in the tropics after Ruiz in 1985, that long-term trends in SAGE II ozone

  5. 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.

  6. Aerosol Classification using Airborne High Spectral Resolution Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Obland, M. D.; Rogers, R.; Butler, C. F.; Cook, A.; Harper, D.; Froyd, K. D.

    2011-12-01

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

  7. 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

  8. 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.

  9. Constraining aerosol optical models using ground-based, collocated particle size and mass measurements in variable air mass regimes during the 7-SEAS/Dongsha experiment

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    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 (λ = 550 nm) 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 sulfate, nitrate, and elemental carbon. Achieving full optical closure is hampered by limitations in accounting for the role of water vapor in the system, uncertainties in the instruments and the need for further knowledge in the source apportionment of the model's major chemical components. Nonetheless, 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 sulfate 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. Consistency between the measured and modeled optical parameters serves as an

  10. 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

  11. Airborne measurements of spectral direct aerosol radiative forcing in the Intercontinental chemical Transport Experiment/Intercontinental Transport and Chemical Transformation of anthropogenic pollution, 2004

    NASA Astrophysics Data System (ADS)

    Redemann, Jens; Pilewskie, Peter; Russell, Philip B.; Livingston, John M.; Howard, Steve; Schmid, Beat; Pommier, John; Gore, Warren; Eilers, James; Wendisch, Manfred

    2006-07-01

    As part of the INTEX-NA (Intercontinental chemical Transport Experiment-North America) and ITCT (Intercontinental Transport and Chemical Transformation of anthropogenic pollution) field studies, the NASA Ames 14-channel Airborne Tracking Sunphotometer (AATS-14) and a pair of Solar Spectral Flux Radiometers (SSFR) took measurements from aboard a Sky Research Jet stream 31 (J31) aircraft during 19 science flights over the Gulf of Maine during 12 July to 8 August 2004. The combination of coincident AATS-14 and SSFR measurements yields plots of net (downwelling minus upwelling) spectral irradiance as a function of aerosol optical depth (AOD) as measured along horizontal flight legs. By definition, the slope of these plots yields the instantaneous change in net irradiance per unit AOD change and is referred to as the instantaneous spectral aerosol radiative forcing efficiency, Ei (W m-2 nm-1). Numerical integration over a given spectral range yields the instantaneous broadband aerosol radiative forcing efficiency (W m-2). This technique for deriving Ei is called the aerosol gradient method. Within 10 case studies considered suitable for our analysis we found a high variability in the derived instantaneous aerosol forcing efficiencies for the visible wavelength range (350-700 nm), with a mean of -79.6 W m-2 and a standard deviation of 21.8 W m-2 (27%). An analytical conversion of the instantaneous forcing efficiencies to 24-hour-average values yielded -45.8 ± 13.1 W m-2 (mean ± std). We present spectrally resolved aerosol forcing efficiencies between 350 and 1670 nm, estimates of the midvisible aerosol single scattering albedo and a comparison of observed broadband forcing efficiencies to previously reported values.

  12. Satellite measurements of tropospheric aerosols

    NASA Technical Reports Server (NTRS)

    Griggs, M.

    1981-01-01

    This investigation uses LANDSAT 2 radiance data and ground-truth measurements of the aerosol optical thickness, obtained previously from five inland sites, to study the usefulness and limitations of the near infrared radiance over inland bodies of water. The linear relationship between LANDSAT 2 MSS7 and aerosol content found in this study can be used to estimate the aerosol content with a standard deviation of 0.42N. Analysis of the data for MSS6 and MSS7 suggest that the larger uncertainty is mostly due to water turbidity, with little contribution from the adjacency effect. The relationship found is best applied to determine an average aerosol content over a period of time at a given target, or an area average at a given time over several targets close together.

  13. 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.

  14. Aerosol measurements from earth orbiting spacecraft

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.

    1982-01-01

    The global aerosol data base evolving from monitoring being done by Stratospheric Aerosol Measurement (SAM) II and Stratospheric Aerosol and Gas Experiment (SAGE) since the fall of 1978 is presented. Data reveal that polar stratospheric clouds (PSC) enhance extinction and optical depths by up to two orders of magnitude and an order of magnitude, respectively. These data are over background 1000 nm values of approximately 1.2 x 10 to the -4th per km, and 1.3 x 10 to the -3rd, respectively. SAGE has offered, for the first time, quantitative measurements of volcanic eruptions on a nearly global basis, and estimates are given for the amount of aerosol injected into the stratosphere from each volcano. For example, Northern Hemisphere aerosol was enhanced by more than 100% by the 1980 eruption of Mount St. Helens, which produced about 0.32 x 10 to the 6th metric tons of aerosol. A cirrus cloud data base is being developed which will be useful in earth radiation and water vapor budget studies. Cross-section, contour, and temperature variation diagrams are included.

  15. Retrieval of ozone and nitrogen dioxide concentrations from Stratospheric Aerosol and Gas Experiment III (SAGE III) measurements using a new algorithm

    NASA Astrophysics Data System (ADS)

    Polyakov, A. V.; Timofeyev, Y. M.; Ionov, D. V.; Virolainen, Y. A.; Steele, H. M.; Newchurch, M. J.

    2005-03-01

    We describe a new inversion algorithm developed for the retrieval of atmospheric constituents from Stratospheric Aerosol and Gas Experiment III (SAGE III) solar occultation measurements. The methodology differs from the operational (NASA) algorithm in several important ways. Our algorithm takes account of the finite altitude and spectral resolution of the measurements by integrating over the viewing window spectrally and spatially. We solve the problem nonlinearly by using optimal estimation theory, and we use an aerosol parameterization scheme based on eigenvectors derived from existing empirical and modeled information about their microphysical properties. The first four of these eigenvectors are employed in the retrieval algorithm to describe the spectral variation of the aerosol extinction. We retrieve ozone and nitrogen dioxide number densities and aerosol extinction from transmission measurements at 41 channels from 0.29 to 1.55 μm. In this paper we describe the results of the gas retrievals. Numerical simulations test the accuracy of the scheme, and subsequent retrievals from SAGE III transmission data for the period between May and October 2002 produce profiles of O3 and NO2. Comparisons of the O3 and NO2 profiles with those obtained using the SAGE III operational algorithm and with those from independent measurements made by satellites, ozonesondes, and lidar indicate agreement in ozone measurements in the middle and upper stratosphere significantly closer than the natural variability and agreement in the lower stratosphere and upper troposphere approximately equal to the natural variability.

  16. 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.

  17. Airborne High Spectral Resolution Lidar Measurements of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

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

  18. Airborne Atmospheric Aerosol Measurement System

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Aerosol retrieval experiments in the ESA Aerosol_cci project

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

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

    SciTech Connect

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

    1992-11-01

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

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

    NASA Technical Reports Server (NTRS)

    Bowdle, David A.

    1985-01-01

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

  6. 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.

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

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.

    1986-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  9. Detailed Aerosol Characterization using Polarimetric Measurements

    NASA Astrophysics Data System (ADS)

    Hasekamp, Otto; di Noia, Antonio; Stap, Arjen; Rietjens, Jeroen; Smit, Martijn; van Harten, Gerard; Snik, Frans

    2016-04-01

    Anthropogenic aerosols are believed to cause the second most important anthropogenic forcing of climate change after greenhouse gases. In contrast to the climate effect of greenhouse gases, which is understood relatively well, the negative forcing (cooling effect) caused by aerosols represents the largest reported uncertainty in the most recent assessment of the International Panel on Climate Change (IPCC). To reduce the large uncertainty on the aerosol effects on cloud formation and climate, accurate satellite measurements of aerosol optical properties (optical thickness, single scattering albedo, phase function) and microphysical properties (size distribution, refractive index, shape) are essential. There is growing consensus in the aerosol remote sensing community that multi-angle measurements of intensity and polarization are essential to unambiguously determine all relevant aerosol properties. This presentations adresses the different aspects of polarimetric remote sensing of atmospheric aerosols, including retrieval algorithm development, validation, and data needs for climate and air quality applications. During past years, at SRON-Netherlands Instite for Space Research retrieval algorithms have been developed that make full use of the capabilities of polarimetric measurements. We will show results of detailed aerosol properties from ground-based- (groundSPEX), airborne- (NASA Research Scanning Polarimeter), and satellite (POLDER) measurements. Also we will discuss observational needs for future instrumentation in order to improve our understanding of the role of aerosols in climate change and air quality.

  10. A review of atmospheric aerosol measurements

    NASA Astrophysics Data System (ADS)

    McMurry, Peter H.

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

  11. Lindenberg Aerosol Characterization Experiment 1998 (LACE 98): Overview

    NASA Astrophysics Data System (ADS)

    Ansmann, Albert; Wandinger, Ulla; Wiedensohler, Alfred; Leiterer, Ulrich

    2002-11-01

    Backscattering and absorption of solar radiation by aerosol particles are an important source of uncertainty in climate predictions. Integrated research on the radiative properties of aerosol may reduce this uncertainty. The Lindenberg Aerosol Characterization Experiment 1998 (LACE 98) contributes to this aim. LACE 98 took place between 13 July and 12 August 1998, near Berlin, Germany. The Lindenberg Meteorological Observatory (52.2°N, 14.1°E) was chosen as the central field site because of its long record with aerosol optical-depth data. Measurements were performed from three aircraft, with one airborne and four ground-based lidars, and at a ground station. The meteorological situations in which intensive observations were carried out included clean and polluted air masses as characterized by low and high aerosol optical depths. This introductory paper gives an overview of the LACE 98 goals, instrumentation, meteorological and aerosol properties, and reports on the key findings as a guide to the results presented in the more detailed papers that follow. A very remarkable finding should be mentioned beforehand because of its unique character: on 9-10 August 1998, a free-tropospheric aerosol layer was observed that originated from forest fires in western Canada.

  12. 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.

  13. The 1997 El Niño impact on clouds, water vapour, aerosols and reactive trace gases in the troposphere, as measured by the Global Ozone Monitoring Experiment

    NASA Astrophysics Data System (ADS)

    Loyola, D.; Valks, P.; Ruppert, T.; Richter, A.; Wagner, T.; Thomas, W.; van der A, R.; Meisner, R.

    2006-03-01

    The El Niño event of 1997/1998 caused dry conditions over the Indonesian area that were followed by large scale forest and savannah fires over Kalimantan, Sumatra, Java, and parts of Irian Jaya. Biomass burning was most intense between August and October 1997, and large amounts of ozone precursors, such as nitrogen oxides, carbon monoxide and hydrocarbons were emitted into the atmosphere. In this work, we use satellite measurements from the Global Ozone Monitoring Experiment (GOME) sensor to study the teleconnections between the El Niño event of 1997 and the Indonesian fires, clouds, water vapour, aerosols and reactive trace gases (nitrogen dioxide, formaldehyde and ozone) in the troposphere.

  14. Lidar backscattering measurements of background stratospheric aerosols

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  15. Measurement of Transport Properties of Aerosolized Nanomaterials

    PubMed Central

    Ku, Bon Ki; Kulkarni, Pramod

    2015-01-01

    Airborne engineered nanomaterials such as single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), functionalized MWCNT, graphene, fullerene, silver and gold nanorods were characterized using a tandem system of a differential mobility analyzer and an aerosol particle mass analyzer to obtain their airborne transport properties and understand their relationship to morphological characteristics. These nanomaterials were aerosolized using different generation methods such as electrospray, pneumatic atomization, and dry aerosolization techniques, and their airborne transport properties such as mobility and aerodynamic diameters, mass scaling exponent, dynamic shape factor, and effective density were obtained. Laboratory experiments were conducted to directly measure mobility diameter and mass of the airborne nanomaterials using tandem mobility-mass measurements. Mass scaling exponents, aerodynamic diameters, dynamic shape factors and effective densities of mobility-classified particles were obtained from particle mass and the mobility diameter. Microscopy analysis using Transmission Electron Microscopy (TEM) was performed to obtain morphological descriptors such as envelop diameter, open area, aspect ratio, and projected area diameter. The morphological information from the TEM was compared with measured aerodynamic and mobility diameters of the particles. The results showed that aerodynamic diameter is smaller than mobility diameter below 500 nm by a factor of 2 to 4 for all nanomaterials except silver and gold nanorods. Morphologies of MWCNTs generated by liquid-based method, such as pneumatic atomization, are more compact than those of dry dispersed MWCNTs, indicating that the morphology depends on particle generation method. TEM analysis showed that projected area diameter of MWCNTs appears to be in reasonable agreement with mobility diameter in the size range from 100 – 400 nm. Principal component analysis of the obtained airborne particle

  16. 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

  17. Measuring Sodium Chloride Contents of Aerosols

    NASA Technical Reports Server (NTRS)

    Sinha, M. P.; Friedlander, S. K.

    1986-01-01

    Amount of sodium chloride in individual aerosol particles measured in real time by analyzer that includes mass spectrometer. Analyzer used to determine mass distributions of active agents in therapeutic or diagnostic aerosols derived from saline solutions and in analyzing ocean spray. Aerosol particles composed of sodium chloride introduced into oven, where individually vaporized on hot wall. Vapor molecules thermally dissociated, and some of resulting sodium atoms ionized on wall. Ions leave oven in burst and analyzed by spectrometer, which is set to monitor sodium-ion intensity.

  18. ARM Cloud-Aerosol-Precipitation Experiment (ACAPEX) Field Campaign Report

    SciTech Connect

    Leung, L Ruby

    2016-03-01

    The U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility’s ARM Cloud-Aerosol-Precipitation Experiment (ACAPEX) field campaign contributes to CalWater 2015, a multi-agency field campaign that aims to improve understanding of atmospheric rivers and aerosol sources and transport that influence cloud and precipitation processes. The ultimate goal is to reduce uncertainties in weather predictions and climate projections of droughts and floods in California. With the DOE G-1 aircraft and ARM Mobile Facility 2 (AMF2) well equipped for making aerosol and cloud measurements, ACAPEX focuses specifically on understanding how aerosols from local pollution and long-range transport affect the amount and phase of precipitation associated with atmospheric rivers. ACAPEX took place between January 12, 2015 and March 8, 2015 as part of CalWater 2015, which included four aircraft (DOE G-1, National Oceanic and Atmospheric Administration [NOAA] G-IV and P-3, and National Aeronautics and Space Administration [NASA] ER-2), the NOAA research ship Ron Brown, carrying onboard the AMF2, National Science Foundation (NSF)-sponsored aerosol and precipitation measurements at Bodega Bay, and the California Department of Water Resources extreme precipitation network.

  19. Ganges Valley Aerosol Experiment: Science and Operations Plan

    SciTech Connect

    Kotamarthi, VR

    2010-06-21

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

  20. Requirements For Lidar Aerosol and Ozone Measurements

    NASA Astrophysics Data System (ADS)

    Frey, S.; Woeste, L.

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

  1. AVHRR measurements of atmospheric aerosols over oceans

    NASA Astrophysics Data System (ADS)

    Griggs, M.

    1981-11-01

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

  2. 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

  3. Synchronised Aerosol Mass Spectrometer Measurements across Europe

    NASA Astrophysics Data System (ADS)

    Nemitz, Eiko

    2010-05-01

    Up to twelve Aerodyne Aerosol Mass Spectrometers (AMSs) were operated simultaneously at rural and background stations (EMEP and EUSAAR sites) across Europe. Measurements took place during three intensive periods, in collaboration between the European EUCAARI IP and the EMEP monitoring activities under the UNECE Convention for Long-Range Transboundary Air Pollution (CLRTAP) during three contrasting months (May 2008, Sep/Oct 2008, Feb/Mar 2009). These measurements were conducted, analysed and quality controlled carefully using a unified protocol, providing the largest spatial database of aerosol chemical composition measured with a unified online technique to date, and a unique snapshots of the European non-refractory submicron aerosol climatology. As campaign averages over all active monitoring sites, organics represent 28 to 43%, sulphate 18 to 25%, ammonium 13 to 15% and nitrate 15 to 36% of the resolved aerosol mass, with the highest relative nitrate contribution during the Feb/Mar campaign. The measurements demonstrate that in NW Europe (e.g. Ireland, UK, The Netherlands, Germany, Switzerland) the regional submicron aerosol tends to be neutralised and here nitrates make a major contribution to the aerosol mass. By contrast, periods with low nitrate and acidic aerosol were observed at sites in S and E Europe (e.g. Greece, Finland), presumably due to a combination of larger SO2 point sources in Easter Europe, smaller local NH3 sources and, in the case of Greece, higher temperatures. While at the more marine and remote sites (Ireland, Scotland, Finland) nitrate concentrations were dominated by episodic transport phenomena, at continental sites (Switzerland, Germany, Hungary) nitrate followed a clear diurnal cycle, reflecting the thermodynamic behaviour of ammonium nitrate. The datasets clearly shows spatially co-ordinated, large-scale pollution episodes of organics, sulphate and nitrate, the latter being most pronounced during the Feb/Mar campaign. At selected

  4. VIIRS Aerosol Products During the SEAC4RS Field Experiment

    NASA Astrophysics Data System (ADS)

    Remer, L. A.; Munchak, L. A.; Huang, J.; Martins, J. V.; Espinosa, R.; Orozco, D.

    2014-12-01

    The Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field experiment that took place during August and September 2013 offered an in depth portrait of the aerosol system over much of the continental United States. Heavily instrumented aircraft, including the NASA DC-8 sampled a wide variety of aerosol types including transported Saharan dust, both fresh and aged smoke from western wildfires, urban pollution plumes and also biogenic aerosol produced by the "green volcano" in the vegetated Ozarks. Complementing these aircraft measurements was an enhanced array of AERONET stations sprinkled across the country and also concentrated in a mesoscale array near the home base of Houston Texas. This rich collection of suborbital aerosol information permits a more comprehensive evaluation of the VIIRS aerosol product that includes validation of the products across the mesoscale and choices of case studies in which we can delve deeper into the VIIRS retrieval to test algorithm assumptions. We will compare VIIRS retrievals during SEAC4RS with MODIS retrievals, with AERONET observations and retrievals, and with measurements and retrievals from the Polar Imaging Nephelometer (PI-Neph) that flew aboard the NASA DC-8.

  5. Aerosol classification using airborne High Spectral Resolution Lidar measurements - methodology and examples

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Rogers, R. R.; Obland, M. D.; Butler, C. F.; Cook, A. L.; Harper, D. B.; Froyd, K. D.

    2012-01-01

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

  6. Aerosol classification using airborne High Spectral Resolution Lidar measurements - methodology and examples

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Rogers, R. R.; Obland, M. D.; Butler, C. F.; Cook, A. L.; Harper, D. B.; Froyd, K. D.

    2011-09-01

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

  7. Aerosol studies during the ESCOMPTE experiment: an overview

    NASA Astrophysics Data System (ADS)

    Cachier, Hélène; Aulagnier, Fabien; Sarda, Roland; Gautier, François; Masclet, Pierre; Besombes, Jean-Luc; Marchand, Nicolas; Despiau, Serge; Croci, Delphine; Mallet, Marc; Laj, Paolo; Marinoni, Angela; Deveau, Pierre-Alexandre; Roger, Jean-Claude; Putaud, Jean-Philippe; Van Dingenen, Rita; Dell'Acqua, Alessandro; Viidanoja, Jyrkki; Martins-Dos Santos, Sebastiao; Liousse, Cathy; Cousin, Frédéric; Rosset, Robert; Gardrat, Eric; Galy-Lacaux, Corinne

    2005-03-01

    The "Expérience sur Site pour COntraindre les Modèles de Pollution atmosphérique et de Transport d'Emissions" (ESCOMPTE) experiment took place in the Southern part of France in the Marseilles/Fos-Berre region during 6 weeks in June and July 2001. One task was to document the regional sources of atmospheric particles and to gain some insight into the aerosol transformations in the atmosphere. For this purpose, seven sites were chosen and equipped with the same basic instrumentation to obtain the chemical closure of the bulk aerosol phase and size-segregated samples. Some specific additional experiments were conducted for the speciation of the organic matter and the aerosol size distribution in number. Finally, four multiwavelength sun-photometers were also deployed during the experiment. Interestingly, in this region, three intense aerosol sources (urban, industrial and biogenic) are very active, and data show consistent results, enlightening an important background of particles over the whole ESCOMPTE domain. Notable is the overwhelming importance of the carbonaceous fraction (comprising primary and secondary particles), which is always more abundant than sulphates. Particle size studies show that, on average, more than 90% of the mean regional aerosol number is found on a size range smaller than 300 nm in diameter. The most original result is the evidence of the rapid formation of secondary aerosols occurring in the whole ESCOMPTE domain. This formation is much more important than that usually observed at these latitudes since two thirds of the particulate mass collected off source zones is estimated to be generated during atmospheric transport. On the other hand, the marine source has poor influence in the region, especially during the overlapping pollution events of Intensive Observation Periods (IOP). Preliminary results from the 0D and 3D versions of the MesoNH-aerosol model show that, with optimised gas and particle sources, the model accounts

  8. ELECTRICAL AEROSOL DETECTOR (EAD) MEASUREMENTS AT THE ST. LOUIS SUPERSITE

    EPA Science Inventory

    The Model 3070A Electrical Aerosol Detector (EAD) measures a unique aerosol parameter called total aerosol length. Reported as mm/cm3, aerosol length can be thought of as a number concentration times average diameter, or simply as d1 weighting. This measurement falls between nu...

  9. 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.

  10. 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.

  11. 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.

  12. Aerosol and Plasma Measurements in Noctilucent Clouds

    NASA Technical Reports Server (NTRS)

    Robertson, Scott

    2000-01-01

    The purpose of this project was to develop rocket-borne probes to detect charged aerosol layers in the mesosphere. These include sporadic E layers, which have their origin in meteoric dust, and noctilucent clouds, which form in the arctic summer and are composed of ice crystals. The probe being developed consists of a charge collecting patch connected to a sensitive electrometer which measures the charge deposited on the patch by impacting aerosols. The ambient electrons and light ions in the mesosphere are prevented from being collected by a magnetic field. The magnetic force causes these lighter particles to turn so that they miss the collecting patch.

  13. Novel Measurements of Aerosol Particle Interfaces Using Biphasic Microfluidics

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  14. 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%.

  15. Airborne Measurements of Aerosol Size Distributions During PACDEX

    NASA Astrophysics Data System (ADS)

    Rogers, D. C.; Gandrud, B.; Campos, T.; Kok, G.; Stith, J.

    2007-12-01

    The Pacific Dust Experiment (PACDEX) is an airborne project that attempts to characterize the indirect aerosol effect by tracing plumes of dust and pollution across the Pacific Ocean. This project occurred during April-May 2007 and used the NSF/NCAR HIAPER research aircraft. When a period of strong generation of dust particles and pollution was detected by ground-based and satellite sensors, then the aircraft was launched from Colorado to Alaska, Hawaii, and Japan. Its mission was to intercept and track these plumes from Asia, across the Pacific Ocean, and ultimately to the edges of North America. For more description, see the abstract by Stith and Ramanathan (this conference) and other companion papers on PACDEX. The HIAPER aircraft carried a wide variety of sensors for measuring aerosols, cloud particles, trace gases, and radiation. Sampling was made in several weather regimes, including clean "background" air, dust and pollution plumes, and regions with cloud systems. Altitude ranges extended from 100 m above the ocean to 13.4 km. This paper reports on aerosol measurements made with a new Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), a Radial Differential Mobility Analyzer (RDMA), a water-based CN counter, and a Cloud Droplet Probe (CDP). These cover the size range 10 nm to 10 um diameter. In clear air, dust was detected with the UHSAS and CDP. Polluted air was identified with high concentrations of carbon monoxide, ozone, and CN. Aerosol size distributions will be presented, along with data to define the context of weather regimes.

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

    NASA Astrophysics Data System (ADS)

    Orozco, Daniel

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

  17. SAGE II aerosol validation: selected altitude measurements, including particle micromeasurements.

    PubMed

    Oberbeck, V R; Livingston, J M; Russell, P B; Pueschel, R F; Rosen, J N; Osborn, M T; Kritz, M A; Snetsinger, K G; Ferry, G V

    1989-06-20

    Correlative aerosol measurements taken at a limited number of altitudes during coordinated field experiments are used to test the validity of particulate extinction coefficients derived from limb path solar radiance measurements taken by the Stratospheric Aerosol and Gas Experiment (SAGE) II Sun photometer. In particular, results are presented from correlative measurement missions that were conducted during January 1985, August 1985, and July 1986. Correlative sensors included impactors, laser spectrometers, and filter samplers aboard an U-2-airplane, an upward pointing lidar aboard a P-3 airplane, and balloon-borne optical particle counters (dustsondes). The main body of this paper focuses on the July 29, 1986, validation experiment, which minimized the many difficulties (e.g., spatial and temporal inhomogeneities, imperfect coincidences) that can complicate the validation process. On this day, correlative aerosol measurements taken at an altitude of 20.5 km agreed with each other within their respective uncertainties, and particulate extinction values calculated at SAGE II wavelengths from these measurements validated corresponding SAGE II values. Additional validation efforts on days when measurement and logistical conditions were much less favorable for validation are discussed in an appendix.

  18. Chamber LIDAR measurements of aerosolized biological simulants

    NASA Astrophysics Data System (ADS)

    Brown, David M.; Thrush, Evan P.; Thomas, Michael E.; Siegrist, Karen M.; Baldwin, Kevin; Quizon, Jason; Carter, Christopher C.

    2009-05-01

    A chamber aerosol LIDAR is being developed to perform well-controlled tests of optical scattering characteristics of biological aerosols, including Bacillus atrophaeus (BG) and Bacillus thuringiensis (BT), for validation of optical scattering models. The 1.064 μm, sub-nanosecond pulse LIDAR allows sub-meter measurement resolution of particle depolarization ratio or backscattering cross-section at a 1 kHz repetition rate. Automated data acquisition provides the capability for real-time analysis or recording. Tests administered within the refereed 1 cubic meter chamber can provide high quality near-field backscatter measurements devoid of interference from entrance and exit window reflections. Initial chamber measurements of BG depolarization ratio are presented.

  19. 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.

  20. Measurements of Semi-volatile Aerosol and Its Effect on Aerosol Optical Properties During Southern Oxidant and Aerosol Study

    NASA Astrophysics Data System (ADS)

    Khlystov, A.; Grieshop, A. P.; Saha, P.; Subramanian, R.

    2013-12-01

    Semi-volatile compounds, including particle-bound water, comprise a large part of aerosol mass and have a significant influence on aerosol lifecycle and its optical properties. Understanding the properties of semi-volatile compounds, especially those pertaining to gas/aerosol partitioning, is of critical importance for our ability to predict concentrations and properties of ambient aerosol. A set of state-of-the-art instruments was deployed at the SEARCH site near Centerville, AL during the Southern Oxidant and Aerosol Study (SOAS) campaign in summer 2013 to measure the effect of temperature and relative humidity on aerosol size distribution, composition and optical properties. Light scattering and absorption by temperature- and humidity-conditioned aerosols was measured using three photo-acoustic extinctiometers (PAX) at three wavelengths (405 nm, 532 nm, and 870 nm). In parallel to these measurements, a long residence time temperature-stepping thermodenuder and a variable residence time constant temperature thermodenuder in combination with three SMPS systems and an Aerosol Chemical Speciation Monitor (ACSM) were used to assess aerosol volatility and kinetics of aerosol evaporation. It was found that both temperature and relative humidity have a strong effect on aerosol optical properties. The variable residence time thermodenuder data suggest that aerosol equilibrated fairly quickly, within 2 s, in contrast to other ambient observations. Preliminary analysis show that approximately 50% and 90% of total aerosol mass evaporated at temperatures of 100 C and 180C, respectively. Evaporation varied substantially with ambient aerosol loading and composition and meteorology. During course of this study, T50 (temperatures at which 50% aerosol mass evaporates) varied from 60 C to more than 120 C.

  1. Electronic cigarette aerosol particle size distribution measurements.

    PubMed

    Ingebrethsen, Bradley J; Cole, Stephen K; Alderman, Steven L

    2012-12-01

    The particle size distribution of aerosols produced by electronic cigarettes was measured in an undiluted state by a spectral transmission procedure and after high dilution with an electrical mobility analyzer. The undiluted e-cigarette aerosols were found to have particle diameters of average mass in the 250-450 nm range and particle number concentrations in the 10(9) particles/cm(3) range. These measurements are comparable to those observed for tobacco burning cigarette smoke in prior studies and also measured in the current study with the spectral transmission method and with the electrical mobility procedure. Total particulate mass for the e-cigarettes calculated from the size distribution parameters measured by spectral transmission were in good agreement with replicate determinations of total particulate mass by gravimetric filter collection. In contrast, average particle diameters determined for e-cigarettes by the electrical mobility method are in the 50 nm range and total particulate masses calculated based on the suggested diameters are orders of magnitude smaller than those determined gravimetrically. This latter discrepancy, and the very small particle diameters observed, are believed to result from almost complete e-cigarette aerosol particle evaporation at the dilution levels and conditions of the electrical mobility analysis. A much smaller degree, ~20% by mass, of apparent particle evaporation was observed for tobacco burning cigarette smoke. The spectral transmission method is validated in the current study against measurements on tobacco burning cigarette smoke, which has been well characterized in prior studies, and is supported as yielding an accurate characterization of the e-cigarette aerosol particle size distribution.

  2. Aerosol Formation In The Free Troposphere: Aircraft and Laboratory Measurements of Ionic and Gaseous Aerosol Precursors

    NASA Astrophysics Data System (ADS)

    Arnold, F.

    Aerosol formation seems to be very efficient in the upper troposphere (UT) as in- dicated by the frequent presence of numerous very small and therefore very young aerosol particles. Aersosol formation proceeds via nucleation of supersaturated low volatility trace gases (LVG) involving either a homogeneous (HONU) or an ion- induced (INU) mechanism. LVG experience rapid removal by condenstation on prefer- ably pre-existing aerosol particles and therefore LVG must be formed locally in the UT by photochemical conversion of precursor gases. A prominent example is gaseous sulfuric acid which is formed from SO2. This SO2 originates at least in the northern hemisphere mostly from fossil fuel combustion at ground-level and to some part origi- nates also from jet aircraft cruising in the UT. Other conceivable LVG's are low volatil- ity organic compounds. After formation by nucleation new particles may experience condensational growth involving LVG. Alternatively new particles may experience scavenging by attachment to pre-existing larger particles. The LVG-concentration has a strong influence on the growth-rate of new particles and thereby on the possibil- ity for growth to the size of a cloud condensation nucleus. Unfortunately present knowledge on free tropospheric LVG is rather poor. Here will be reported free tropo- spheric aircraft-based measurements of ionic and gaseous aerosol-precursors. These include both measurements in the "background" FT as well as measurements in ex- haust plumes of jet aircraft cruising in the UT. Furthermore accompanying new labo- ratory investigations of INU and measurements behind aircraft jet engines at ground- level will also be adressed.

  3. Ground-Based Aerosol Measurements

    EPA Science Inventory

    Atmospheric particulate matter (PM) is a complex chemical mixture of liquid and solid particles suspended in air (Seinfeld and Pandis 2016). Measurements of this complex mixture form the basis of our knowledge regarding particle formation, source-receptor relationships, data to ...

  4. Elevated layers of BC aerosols over Indian region and its implications: Results from Regional Aerosol Warming Experiment (RAWEX)

    NASA Astrophysics Data System (ADS)

    Babu, S.; Krishnamoorthy, K.; Satheesh, S.; Gogoi, M. M.; Nair, V. S.; Kompalli, S. K.; Chaubey, J.

    2012-12-01

    In the context of atmospheric warming by elevated layers of absorbing aerosols and its consequence on regional climate such as Indian monsoon, the Regional Aerosol Warming Experiment (RAWEX) was formulated under Aerosol Radiative Forcing over India (ARFI) Project of Indian Space Research Organisation - Geosphere Biosphere Program (ISRO-GBP). As a part of RAWEX, an aerosol observatory was established at a high altitude Himalayan location (Hanle, 32.76°N, 78.95°E and 4520 m msl) to characterise the long term changes in columnar aerosol optical depth (AOD), black carbon aerosols as well as ultra fine particles at free troposphere heights . In addition, extensive measurements of the vertical distribution of BC along with concurrent measurements of atmospheric parameters were also undertaken using high altitude balloons from central part of India. Seasonal variation of aerosol BC as well as AOD showed enhanced loading during pre- monsoon season at the high altitudes associated with the advection from west Asian region as well as due to vertical transport from the plains. However, the seasonal and annual mean BC over Hanle is found to be significantly lower than the corresponding values over other Himalayan stations. The altitude distribution of BC over central Indian region also showed enhanced concentration at free troposphere altitudes during the pre-monsoon season. The elevated layers of BC cause change in the environmental lapse rate due to heating by BC aerosols at an altitude region of 4 to 5 km. The change in environmental lapse rate and increase in atmospheric stability leads to further trapping of BC aerosols at higher altitudes, thus raises an interesting question : "Do BC layers build 'their own homes' up in the atmosphere?"

  5. Apparatus for rapid measurement of aerosol bulk chemical composition

    DOEpatents

    Lee, Yin-Nan E.; Weber, Rodney J.

    2003-01-01

    An apparatus and method for continuous on-line measurement of chemical composition of aerosol particles with a fast time resolution are provided. The apparatus includes a modified particle size magnifier for producing activated aerosol particles and a collection device which collects the activated aerosol particles into a liquid stream for quantitative analysis by analytical methods. The method provided for on-line measurement of chemical composition of aerosol particles includes exposing aerosol carrying sample air to hot saturated steam thereby forming activated aerosol particles; collecting the activated aerosol particles by a collection device for delivery as a jet stream onto an impaction surface; flushing off the activated aerosol particles from the impaction surface into a liquid stream for delivery of the collected liquid stream to an analytical instrument for quantitative measurement.

  6. Apparatus for rapid measurement of aerosol bulk chemical composition

    DOEpatents

    Lee, Yin-Nan E.; Weber, Rodney J.; Orsini, Douglas

    2006-04-18

    An apparatus for continuous on-line measurement of chemical composition of aerosol particles with a fast time resolution is provided. The apparatus includes an enhanced particle size magnifier for producing activated aerosol particles and an enhanced collection device which collects the activated aerosol particles into a liquid stream for quantitative analysis by analytical means. Methods for on-line measurement of chemical composition of aerosol particles are also provided, the method including exposing aerosol carrying sample air to hot saturated steam thereby forming activated aerosol particles; collecting the activated aerosol particles by a collection device for delivery as a jet stream onto an impaction surface; and flushing off the activated aerosol particles from the impaction surface into a liquid stream for delivery of the collected liquid stream to an analytical instrument for quantitative measurement.

  7. 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

  8. Stackable differential mobility analyzer for aerosol measurement

    DOEpatents

    Cheng, Meng-Dawn; Chen, Da-Ren

    2007-05-08

    A multi-stage differential mobility analyzer (MDMA) for aerosol measurements includes a first electrode or grid including at least one inlet or injection slit for receiving an aerosol including charged particles for analysis. A second electrode or grid is spaced apart from the first electrode. The second electrode has at least one sampling outlet disposed at a plurality different distances along its length. A volume between the first and the second electrode or grid between the inlet or injection slit and a distal one of the plurality of sampling outlets forms a classifying region, the first and second electrodes for charging to suitable potentials to create an electric field within the classifying region. At least one inlet or injection slit in the second electrode receives a sheath gas flow into an upstream end of the classifying region, wherein each sampling outlet functions as an independent DMA stage and classifies different size ranges of charged particles based on electric mobility simultaneously.

  9. Aircraft measurements of biomass burning aerosol over West Africa during DABEX

    NASA Astrophysics Data System (ADS)

    Johnson, B. T.; Osborne, S. R.; Haywood, J. M.; Harrison, M. A. J.

    2008-12-01

    This paper investigates the properties of biomass burning aerosols over West Africa using data from the UK FAAM aircraft during the Dust and Biomass-burning Experiment (DABEX). Aged biomass burning aerosols were widespread across the region, often at altitudes up to 4 km. Fresh biomass burning aerosols were observed at low altitudes by flying through smoke plumes from agricultural fires. The aircraft measured aerosol size distributions, optical properties, and vertical distributions. Single scattering albedo varied from 0.73 to 0.93 (at 0.55 μm) in aerosol layers dominated by biomass burning aerosol. We attribute much of this variation to the variable proportion of mineral dust and biomass burning aerosol. We estimate the single scattering albedo of aged biomass burning aerosol to be around 0.81 with an instrumental uncertainty of ±0.05. External mixing, and possibly internal mixing, between the biomass burning aerosol and mineral dust presents an additional source of uncertainty in this estimate. The size distributions of biomass burning aerosols were dominated by particles with radii smaller than 0.35 μm. A 20% increase of count mean radius was observed when contrasting fresh and aged biomass burning aerosols, accompanied by changes in the shape of the size distribution. These changes suggest growth by coagulation and condensation. Extinction coefficients, asymmetry parameters, and Angstrom exponents are calculated from Mie theory, using the lognormal fits to the measured size distributions and assumed refractive indices.

  10. Transported acid aerosols measured in southern Ontario

    NASA Astrophysics Data System (ADS)

    Keeler, Gerald J.; Spengler, John D.; Koutrakis, Petros; Allen, George A.; Raizenne, Mark; Stern, Bonnie

    During the period 29 June 1986-9 August 1986, a field health study assessing the acute health effects of air pollutants on children was conducted at a summer girls' camp on the northern shore of Lake Erie in SW Ontario. Continuous air pollution measurements of SO 2, O 3, NO x, particulate sulfates, light scattering, and meteorological measurements including temperature, dew point, and wind speed and direction were made. Twelve-hour integrated samples of size fractioned particles were also obtained using dichotomous samplers and Harvard impactors equipped with an ammonia denuder for subsequent hydrogen ion determination. Particulate samples were analyzed for trace elements by X-ray fluorescence and Neutron Activation, and for organic and elemental carbon by a thermal/optical technique. The measured aerosol was periodically very acidic with observed 12-h averaged H + concentrations in the range < 10-560 nmoles m -3. The aerosol H + appeared to represent the net strong acidity after H 2SO 4 reaction with NH 3(g). Average daytime concentrations were higher than night-time for aerosol H +, sulfate, fine mass and ozone. Prolonged episodes of atmospheric acidity, sulfate, and ozone were associated with air masses arriving at the measurement site from the west and from the southwest over Lake Erie. Sulfate concentrations measured at the lakeshore camp were more than twice those measured at inland sites during extreme pollution episodes. The concentration gradient observed with onshore flow was potentially due to enhanced deposition near the lakeshore caused by discontinuities in the meteorological fields in this region.

  11. Coarse mode aerosol measurement using a Low Turbulence Inlet

    NASA Astrophysics Data System (ADS)

    Brooke, J.; Bart, M.; Trembath, J.; McQuaid, J. B.; Brooks, B. J.; Osborne, S.

    2012-04-01

    The Sahara desert is a major natural source of global mineral dust emissions (Forster et al., 2007) through the mobilisation and lifting of dust particles into the atmosphere from dust storms. A significant fraction of this dust is in the aerosol coarse mode (Weinzierl et al., 2009). It is highlighted of the difficulty in making accurate and reliable measurements from an aircraft platform, particularly that of coarse mode aerosol (Wendisch et al., 2004). To achieve the measurement of a representative aerosol sample an aerosol inlet, on an aircraft, is required for the delivery of the sample to the instruments making the measurements. Inlet design can modify aerosol size distribution through either underestimating due to aerosol losses or overestimation due to enhancements. The Low Turbulence Inlet (LTI) was designed to improve inlet efficiency. This is achieved by reducing turbulence flow within the tip of the inlet, reducing impaction of particles to the walls of the inlet (Wilson et al., 2004). The LTI further maintains isokinetic sampling flow (free stream velocity, U0 and sampling velocity, U are equal to 1). Dust aerosol over the Sahara desert provides an excellent environment to test and quantify the capabilities of the LTI on the FAAM BAe 146, whilst enabling in-situ dust measurement. The LTI was operated during the Fennec field campaign in June 2011 with 11 flights during the campaign over Mauritania and Mali. We are using the LTI to provide critical information on the sampling characteristics of the inlet used by nearly all aerosol instruments inside the aircraft (AMS, Nephelometer, PSAP, and CCN). Inlet experiments were performed with identical Optical Particle Counters (OPC) connected to the rosemount and LTI with size distribution for each inlet measured and Rosemount enhancements determined. Rosemount inlet enhancements were determined to be 2 to 4 times for particles up to 2.5 µm. A key parameter in aerosol measurement is size distribution, in which

  12. Time Resolved Measurements of Primary Biogenic Aerosol Particles in Amazonia

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

  13. Aerosol Measurements by the Globally Distributed Micro Pulse Lidar Network

    NASA Technical Reports Server (NTRS)

    Spinhirne, James; Welton, Judd; Campbell, James; Berkoff, Tim; Starr, David (Technical Monitor)

    2001-01-01

    Full time measurements of the vertical distribution of aerosol are now being acquired at a number of globally distributed MP (micro pulse) lidar sites. The MP lidar systems provide full time profiling of all significant cloud and aerosol to the limit of signal attenuation from compact, eye safe instruments. There are currently eight sites in operation and over a dozen planned. At all sited there are also passive aerosol and radiation measurements supporting the lidar data. Four of the installations are at Atmospheric Radiation Measurement program sites. The network operation includes instrument operation and calibration and the processing of aerosol measurements with standard retrievals and data products from the network sites. Data products include optical thickness and extinction cross section profiles. Application of data is to supplement satellite aerosol measurements and to provide a climatology of the height distribution of aerosol. The height distribution of aerosol is important for aerosol transport and the direct scattering and absorption of shortwave radiation in the atmosphere. Current satellite and other data already provide a great amount of information on aerosol distribution, but no passive technique can adequately resolve the height profile of aerosol. The Geoscience Laser Altimeter System (GLAS) is an orbital lidar to be launched in early 2002. GLAS will provide global measurements of the height distribution of aerosol. The MP lidar network will provide ground truth and analysis support for GLAS and other NASA Earth Observing System data. The instruments, sites, calibration procedures and standard data product algorithms for the MPL network will be described.

  14. Aerosol optical properties measurement by recently developed cavity-enhanced aerosol single scattering albedometer

    NASA Astrophysics Data System (ADS)

    Zhao, Weixiong; Xu, Xuezhe; Zhang, Qilei; Fang, Bo; Qian, Xiaodong; Chen, Weidong; Gao, Xiaoming; Zhang, Weijun

    2015-04-01

    Development of appropriate and well-adapted measurement technologies for real-time in-situ measurement of aerosol optical properties is an important step towards a more accurate and quantitative understanding of aerosol impacts on climate and the environment. Aerosol single scattering albedo (SSA, ω), the ratio between the scattering (αscat) and extinction (αext) coefficients, is an important optical parameter that governs the relative strength of the aerosol scattering and absorption capacity. Since the aerosol extinction coefficient is the sum of the absorption and scattering coefficients, a commonly used method for the determination of SSA is to separately measure two of the three optical parameters - absorption, scattering and extinction coefficients - with different instruments. However, as this method involves still different instruments for separate measurements of extinction and absorption coefficients under different sampling conditions, it might cause potential errors in the determination of SSA value, because aerosol optical properties are very sensitive to the sampling conditions such as temperature and relative humidity (RH). In this paper, we report on the development of a cavity-enhanced aerosol single scattering albedometer incorporating incoherent broad-band cavity-enhanced spectroscopy (IBBCEAS) and an integrating sphere (IS) for direct in-situ measurement of aerosol scattering and extinction coefficients on the exact same sample volume. The cavity-enhanced albedometer holds great promise for high-sensitivity and high-precision measurement of ambient aerosol scattering and extinction coefficients (hence absorption coefficient and SSA determination) and for absorbing trace gas concentration. In addition, simultaneous measurements of aerosol scattering and extinction coefficients enable a potential application for the retrieval of particle number size distribution and for faster retrieval of aerosols' complex RI. The albedometer was deployed to

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

    NASA Technical Reports Server (NTRS)

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

  16. 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

  17. Characterization of aerosol events based on the column integrated optical aerosol properties and polarimetric measurements

    NASA Astrophysics Data System (ADS)

    Mandija, Florian; Markowicz, Krzysztof; Zawadzka, Olga

    2016-12-01

    Aerosol optical properties are very useful tools for analyzing their radiative effects, which are directly or indirectly related to the global radiation budget. Investigation of column-integrated aerosol optical properties is a worldwide and well-accepted method. The introduction of new methodologies, like those of operation with polarimetric measurements, represent a new challenge to interpret the measurement data and give more detailed information about the aerosol events and their characteristics. Aerosol optical properties during the period June - August 2015 in AERONET Strzyzow station in Poland were analyzed. The aerosol properties like aerosol optical depth, Ångström exponent, fine mode fraction, fine mode contribution on AOD, asymmetry parameter, single scattering angle are analyzed synergistically with the polarimetric measurements of the degree of polarization in different solar zenith and zenith viewing angles at several wavelengths. The overall results show that aerosol events in Strzyzow were characterized mostly by fine mode aerosols. Backward-trajectories suggest that the majority of air masses come from the west. The principal component of the aerosol load was urban/industrial contamination, especially from the inner part of the continent. Additionally, the maximal values of the degree of linear polarization were found to be dependent on the solar zenith and zenith viewing angles and aerosol optical properties like aerosol optical depth and Ångström exponent. These dependencies were further analyzed in a specific case with very high mean values of AOD500 (0.59) and AE440-870 (1.91). The diurnal variations of aerosol optical properties investigated during this special case, suggest that biomass burning products are the main cause of that aerosol load over the stations.

  18. Analysis of Ambient Aerosol Measurements During PROPHET 2001

    NASA Astrophysics Data System (ADS)

    Delia, A. E.; Garland, R.; Toohey, D. W.; Worsnop, D. R.; Allen, J. O.; Carroll, M. A.; Fortner, E.; Hengel, S.; Lilly, M.; Moody, J.; Huey, G.; Tanner, D.

    2002-12-01

    Aerosol size and composition were measured using an aerosol mass spectrometer, developed by Aerodyne Research, Inc., during PROPHET 2001 (Program for Research on Oxidants: PHotochemistry, Emissions and Transport). Our purpose in this study was to characterize chemical composition and size of ambient aerosols, investigate the effects of transport, and study aerosol microphysics. The site is located in a remote forested area of northern Michigan at the University of Michigan Biological Station, far from any large urban areas and surrounded primarily by deciduous forests. The aerosols at this site can be cataloged into four classes. The two principal classes are distinguished by meteorological conditions. Clean, northerly airflow produced low aerosol mass loadings dominated by organic species. More polluted southerly airflow brought higher aerosol mass loadings dominated by sulfate with an organic contribution. Under both of these conditions, aerosol existed almost entirely in the accumulation size mode of 300-600 nm. In addition to these principal aerosol types, small particle growth was observed on several occasions. It appears that these events occurred primarily during periods of low aerosol mass loading (i.e., northerly airflow) when the low aerosol number provided an opportunity for new particle formation and rapid growth. On at least one occasion, it appears that a large plume of sulfur dioxide that was converted to sulfuric acid near the site may be responsible for new particle formation. The fourth type of aerosol consisted of short events dominated by organic species, apparently diesel exhaust caused by local truck traffic. In addition to the overall aerosol characterization, comparisons with other measurements that affected the aerosol composition or characterized the air masses will be presented and the implications of these results for regional transport of aerosols will be discussed.

  19. Size distribution and scattering phase function of aerosol particles retrieved from sky brightness measurements

    NASA Technical Reports Server (NTRS)

    Kaufman, Y. J.; Gitelson, A.; Karnieli, A.; Ganor, E. (Editor); Fraser, R. S.; Nakajima, T.; Mattoo, S.; Holben, B. N.

    1994-01-01

    particles with r(sub m) less than 0.2 microns and coarse paritcles with r(sub m) greater than 0.7 microns. The 'window' in the tropospheric aerosol in this radius range was used to observe a stable stratospheric aerosol in 1992, with r(sub m) approximately 0.5 microns. A combination of such optical thickness and sky measurements can be used to assess the direct forcing and the climatic impact of aerosol. Systematic inversion for the key aerosol types (sulfates, smoke, dust, and maritime aerosol) of the size distribution and phase function can give the relationship between the aerosol physical and optical properties that can be used to compute the radiative forcing. This forcing can be validated in dedicated field experiments.

  20. Size distribution and scattering phase function of aerosol particles retrieved from sky brightness measurements

    NASA Astrophysics Data System (ADS)

    Kaufman, Y. J.; Gitelson, A.; Karnieli, A.; Ganor, E.; Fraser, R. S.; Nakajima, T.; Mattoo, S.; Holben, B. N.

    1994-05-01

    < 0.2 μm and coarse particles with rm > 0.7 μm. The "window" in the tropospheric aerosol in this radius range was used to observe a stable stratospheric aerosol in 1992, with rm ˜ 0.5 μm. A combination of such optical thickness and sky measurements can be used to assess the direct forcing and the climatic impact of aerosol. Systematic inversion for the key aerosol types (sulfates, smoke, dust, and maritime aerosol) of the size distribution and phase function can give the relationship between the aerosol physical and optical properties that can be used to compute the radiative forcing. This forcing can be validated in dedicated field experiments.

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  2. Global Backscatter Experiment (GLOBE) Results: Aerosol Backscatter Global Distribution and Wavelength Dependence

    NASA Technical Reports Server (NTRS)

    Bowdle, David A.

    1992-01-01

    The GLObal Backscatter Experiment (GLOBE) was initiated by NASA in 1986 as an interagency and international research effort to characterize tropospheric backscatter properties. The primary objective of the program is to develop realistic aerosol backscatter inputs for design and simulation studies for NASA's prospective Laser Atmospheric Wind Sounder (LAWS). To achieve this, GLOBE incorporates several different types of aerosol sensors, which operate from a variety of sensor platforms, covering a wide range of spatial and temporal scales, and measure a diverse set of aerosol physical, chemical, and optical properties. The results of this analysis have provided important new information on the life cycles and physicochemical properties of global scale tropospheric aerosol systems. In addition, GLOBE analytical methods will be useful for the Earth Observing System (EOS) and other studies that involve the assimilation of large, complex atmospheric aerosol databases.

  3. Aerosol-cloud closure study using RPAS measurements

    NASA Astrophysics Data System (ADS)

    Calmer, R.; Roberts, G.; Sanchez, K. J.; Nicoll, K.; Preissler, J.; Ovadnevaite, J.; Sciare, J.; Bronz, M.; Hattenberger, G.; Rosenfeld, D.; Lauda, S.; Hashimshoni, E.

    2015-12-01

    Enhancements in Remotely Piloted Aircraft Systems (RPAS) have increased their possible uses in many fields for the past two decades. For atmospheric research, ultra-light RPAS (< 2.5kg) are now able to fly at altitudes greater than 3 km and even in cloud, which opens new opportunities to understand aerosol-cloud interactions. We are deploying the RPAS as part of the European project BACCHUS (Impact of Biogenic versus Anthropogenic Emissions on Clouds and Climate: towards a Holistic Understanding). Field experiments in Cyprus and Ireland have already been conducted to study aerosol-cloud interactions in climatically different environments. The RPAS are being utilized in this study with the purpose of complementing ground-based observations of cloud condensation nuclei (CCN) to conduct aerosol-cloud closure studies Cloud microphysical properties such as cloud drop number concentration and size can be predicted directly from the measured CCN spectrum and the observed updraft, the vertical component of the wind vector [e.g., Conant et al, 2004]. On the RPAS, updraft measurements are obtained from a 5-hole probe synchronized with an Inertial Measurement Unit (IMU). The RPA (remotely piloted aircraft) are programmed to fly at a level leg just below cloud base to measure updraft measurements while a scanning CCN counter is stationed at ground level. Vertical profiles confirm that CCN measurements on the ground are representative to those at cloud base. An aerosol-cloud parcel model is implemented to model the cloud droplet spectra associated with measured updraft velocities. The model represents the particle size domain with internally mixed chemical components, using a fixed-sectional approach [L. M. Russell and Seinfeld, 1998]. The model employs a dual moment (number and mass) algorithm to calculate growth of particles from one section to the next for non-evaporating species. Temperature profiles, cloud base, updraft velocities and aerosol size and composition, all

  4. Identification of aerosol composition from multi-wavelength lidar measurements

    NASA Technical Reports Server (NTRS)

    Wood, S. A.

    1984-01-01

    This paper seeks to develop the potential of lidar for the identification of the chemical composition of atmospheric aerosols. Available numerical computations suggest that aerosols can be identified by the wavelength dependence of aerosol optical properties. Since lidar can derive the volume backscatter coefficient as a function of wavelength, a multi-wavelength lidar system may be able to provide valuable information on the composition of aerosols. This research theoretically investigates the volume backscatter coefficients for the aerosol classes, sea-salts, and sulfates, as a function of wavelength. The results show that these aerosol compositions can be characterized and identified by their backscatter wavelength dependence. A method to utilize multi-wavelength lidar measurements to discriminate between compositionally different thin aerosol layers is discussed.

  5. 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.

  6. 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

  7. 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.

  8. Measurements of Absorbing Aerosols Using in Situ and Remote Sensing Techniques

    NASA Astrophysics Data System (ADS)

    Martins, J. V.; Martins, J. V.; Kaufman, Y.; Artaxo, P.; Andrea, C.; Yamasoe, M.; Remer, L.

    2001-12-01

    Reliable measurements of light absorption by aerosol particles are essential for an accurate assessment of the climate radiative forcing by aerosol particles. Depending on the absorption properties, the radiative forcing of the aerosols may change from a cooling to a heating effect. New techniques for the remote sensing of aerosol absorption over land and ocean are developed and applied in combination with in situ measurements for validation and addition of complementary information. Spectral measurements show the effects of aerosols on absorption of light from the UV to the near infrared. Depending on particle size and structure, there is a significant absorption component that must be accounted for the radiative forcing in the near infrared. Remote sensing results from MODIS and from the CLAMS field experiment, as well as in situ validation data will be discussed.

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

    NASA Astrophysics Data System (ADS)

    Yoon, Jongmin; Kokhanovsky, Alexander

    2015-04-01

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

  10. Practical application of in situ aerosol measurement

    SciTech Connect

    O`Hern, T.J.; Rader, D.J.

    1993-09-01

    The use of in situ, real-time measurement techniques permits the characterization of airborne droplets and particles under conditions where traditional sampling methods can fail. For example, sampling method rely on the ability to sample and transport particles without biasing the properties of interest, and often are not applicable in harsh environment. Although in situ methods offer unique opportunities in these cases, these techniques introduce new concerns and must be used carefully if accurate measurement are to be made. Several in situ measurement techniques are reviewed here. As the field is rapidly evolving, the discussion is limited to those techniques which: (1) are commercially available, (2) provide real-time output, (3) measure the aerosol size distribution. Discussion is divided between single particle counters (which provide a flux-based or temporal measurement) and ensemble techniques (which provide a concentration-based or spatial measurement). Specific techniques discussed include phase Doppler, Mie scattering, and Fraunhofer diffraction, and commercial instruments based on these techniques.

  11. Aerosol Classification from High Spectral Resolution Lidar Measurements

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    The NASA Langley airborne High Spectral Resolution Lidars, HSRL-1 and HSRL-2, have acquired large datasets of vertically resolved aerosol extinction, backscatter, and depolarization during >30 airborne field missions since 2006. The lidar measurements of aerosol intensive parameters like lidar ratio and color ratio embed information about intrinsic aerosol properties, and are combined to qualitatively classify HSRL aerosol measurements into aerosol types. Knowledge of aerosol type is important for assessing aerosol radiative forcing, and can provide useful information for source attribution studies. However, atmospheric aerosol is frequently not a single pure type, but instead is a mixture, which affects the optical and radiative properties of the aerosol. We show that aerosol intensive parameters measured by lidar can be understood using mixing rules for cases of external mixing. Beyond coarse classification and mixing between classes, variations in the lidar aerosol intensive parameters provide additional insight into aerosol processes and composition. This is illustrated by depolarization measurements at three wavelengths, 355 nm, 532 nm, and 1064 nm, made by HSRL-2. Particle depolarization ratio is an indicator of non-spherical particles. Three cases each have a significantly different spectral dependence of the depolarization ratio, related to the size of the depolarizing particles. For two dust cases, large non-spherical particles account for the depolarization of the lidar light. The spectral dependence reflects the size distribution of these particles and reveals differences in the transport histories of the two plumes. For a smoke case, the depolarization is inferred to be due to the presence of small coated soot aggregates. Interestingly, the depolarization at 355 nm is similar for this smoke case compared to the dust cases, having potential implications for the upcoming EarthCARE satellite, which will measure particle depolarization ratio only at 355 nm.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  13. Development of Portable Aerosol Mobility Spectrometer for Personal and Mobile Aerosol Measurement

    PubMed Central

    Kulkarni, Pramod; Qi, Chaolong; Fukushima, Nobuhiko

    2017-01-01

    We describe development of a Portable Aerosol Mobility Spectrometer (PAMS) for size distribution measurement of submicrometer aerosol. The spectrometer is designed for use in personal or mobile aerosol characterization studies and measures approximately 22.5 × 22.5 × 15 cm and weighs about 4.5 kg including the battery. PAMS uses electrical mobility technique to measure number-weighted particle size distribution of aerosol in the 10–855 nm range. Aerosol particles are electrically charged using a dual-corona bipolar corona charger, followed by classification in a cylindrical miniature differential mobility analyzer. A condensation particle counter is used to detect and count particles. The mobility classifier was operated at an aerosol flow rate of 0.05 L/min, and at two different user-selectable sheath flows of 0.2 L/min (for wider size range 15–855 nm) and 0.4 L/min (for higher size resolution over the size range of 10.6–436 nm). The instrument was operated in voltage stepping mode to retrieve the size distribution, which took approximately 1–2 minutes, depending on the configuration. Sizing accuracy and resolution were probed and found to be within the 25% limit of NIOSH criterion for direct-reading instruments (NIOSH 2012). Comparison of size distribution measurements from PAMS and other commercial mobility spectrometers showed good agreement. The instrument offers unique measurement capability for on-person or mobile size distribution measurements of ultrafine and nanoparticle aerosol.

  14. 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.

  15. Aerosol generation and measurement of multi-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Myojo, Toshihiko; Oyabu, Takako; Nishi, Kenichiro; Kadoya, Chikara; Tanaka, Isamu; Ono-Ogasawara, Mariko; Sakae, Hirokazu; Shirai, Tadashi

    2009-01-01

    Mass production of some kinds of carbon nanotubes (CNT) is now imminent, but little is known about the risk associated with their exposure. It is important to assess the propensity of the CNT to release particles into air for its risk assessment. In this study, we conducted aerosolization of a multi-walled CNT (MWCNT) to assess several aerosol measuring instruments. A Palas RBG-1000 aerosol generator applied mechanical stress to the MWCNT by a rotating brush at feed rates ranging from 2 to 20 mm/h, which the MWCNT was fed to a two-component fluidized bed. The fluidized bed aerosol generator was used to disperse the MWCNT aerosol once more. We monitored the generated MWCNT aerosol concentrations based on number, area, and mass using a condensation particle counter and nanoparticle surface area monitor. Also we quantified carbon mass in MWCNT aerosol samples by a carbon monitor. The shape of aerosolized MWCNT fibers was observed by a scanning electron microscope (SEM). The MWCNT was well dispersed by our system. We found isolated MWCNT fibers in the aerosols by SEM and the count median lengths of MWCNT fibers were 4-6 μm. The MWCNT was quantified by the carbon monitor with a modified condition based on the NIOSH analytical manual. The MWCNT aerosol concentration (EC mass base) was 4 mg/m3 at 2 mm/h in this study.

  16. 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.

  17. Measurements of Aerosol Vertical Profiles and Optical Properties during INDOEX 1999 Using Micro-Pulse Lidars

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; Voss, Kenneth J.; Quinn, Patricia K.; Flatau, Piotr J.; Markowicz, Krzysztof; Campbell, James R.; Spinhirne, James D.; Gordon, Howard R.; Johnson, James E.; Starr, David OC. (Technical Monitor)

    2001-01-01

    Micro-pulse lidar systems (MPL) were used to measure aerosol properties during the Indian Ocean Experiment (INDOEX) 1999 field phase. Measurements were made from two platforms: the NOAA ship RN Ronald H. Brown, and the Kaashidhoo Climate Observatory (KCO) in the Maldives. Sunphotometers were used to provide aerosol optical depths (AOD) needed to calibrate the MPL. This study focuses on the height distribution and optical properties (at 523 nm) of aerosols observed during the campaign. The height of the highest aerosols (top height) was calculated and found to be below 4 km for most of the cruise. The marine boundary layer (MBL) top was calculated and found to be less than 1 km. MPL results were combined with air mass trajectories, radiosonde profiles of temperature and humidity, and aerosol concentration and optical measurements. Humidity varied from approximately 80% near the surface to 50% near the top height during the entire cruise. The average value and standard deviation of aerosol optical parameters were determined for characteristic air mass regimes. Marine aerosols in the absence of any continental influence were found to have an AOD of 0.05 +/- 0.03, an extinction-to-backscatter ratio (S-ratio) of 33 +/- 6 sr, and peak extinction values around 0.05/km (near the MBL top). The marine results are shown to be in agreement with previously measured and expected values. Polluted marine areas over the Indian Ocean, influenced by continental aerosols, had AOD values in excess of 0.2, S-ratios well above 40 sr, and peak extinction values approximately 0.20/km (near the MBL top). The polluted marine results are shown to be similar to previously published values for continental aerosols. Comparisons between MPL derived extinction near the ship (75 m) and extinction calculated at ship-level using scattering measured by a nephelometer and absorption using a PSAP were conducted. The comparisons indicated that the MPL algorithm (using a constant S-ratio throughout the

  18. 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

  19. Deriving simple empirical relationships between aerodynamic and optical aerosol measurements and their application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Different measurement techniques for aerosol characterization and quantification either directly or indirectly measure different aerosol properties (i.e. count, mass, speciation, etc.). Comparisons and combinations of multiple measurement techniques sampling the same aerosol can provide insight into...

  20. SAGE II long-term measurements of stratospheric and upper tropospheric aerosols

    SciTech Connect

    Wang, P.H.; Kent, G.S.; McCormick, M.P.; Thomason, L.W.

    1995-12-31

    The Stratospheric Aerosol and Gas Experiment (SAGE) II solar occultation instrument has been making measurements on stratospheric aerosols and gases continually since October 1984. Observations from the SAGE II instrument provide a valuable long-term data set for study of the aerosol in the stratosphere and aerosol and cloud in the upper troposphere. The period of observation covers the decay phase of material injected by the El Chichon volcanic eruption in 1982, the years 1988--1990 when stratospheric aerosol levels approached background levels, and the period after the eruption of Mount Pinatubo in 1991. The Mount Pinatubo eruption caused the largest perturbation in stratospheric aerosol loading in this century, with effects on stratospheric dynamics and chemistry. The SAGE II data sequence shows the global dispersion of aerosols following the Mount Pinatubo eruption, as well as the changes occurring in stratospheric aerosol mass and surface area. The downward transfer of stratospheric aerosols into the upper troposphere following the earlier eruption of El Chichon is clearly visible. Estimates have been made of the amount of volcanic material lying in the upper troposphere and the way in which this varies with latitude and season.

  1. SAGE measurements of the stratospheric aerosol dispersion and loading from the Soufriere Volcano

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Kent, G. S.; Yue, G. K.; Cunnold, D. M.

    1981-01-01

    Explosions of the Soufriere volcano on the Caribbean Island of St. Vincent reduced two major stratospheric plumes which the stratospheric aerosol and gas experiment (SAGE) satellite tracked to West Africa and the North Atlantic Ocean. The total mass of the stratospheric ejecta measured is less than 0.5% of the global stratospheric aerosol burden. No significant temperature or climate perturbation is expected. It is found that the movement and dispersion of the plumes agree with those deduced from high altitude meteorological data and dispersion theory. The stratospheric aerosol dispersion and loading from the Soufrier volcano was measured.

  2. 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:

  3. 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.

  4. Solar Spectral Radiative Forcing Due to Dust Aerosol During the Puerto Rico Dust Experiment

    NASA Technical Reports Server (NTRS)

    Pilewskie, P.; Bergstrom, R.; Rabbette, M.; Livingston, J.; Russell, P.; Gore, Warren J. (Technical Monitor)

    2000-01-01

    During the Puerto Rico Dust Experiment (PRIDE) upwelling and downwelling solar spectral irradiance was measured on board the SPAWAR Navajo and downwelling solar spectral flux was measured at a surface site using the NASA Ames Solar Spectral Flux Radiometer. These data will be used to determine the net solar radiative forcing of dust aerosol and to quantify the solar spectral radiative energy budget in the presence of elevated aerosol loading. We will assess the variability in spectral irradiance using formal principal component analysis procedures and relate the radiative variability to aerosol microphysical properties. Finally, we will characterize the sea surface reflectance to improve aerosol optical depth retrievals from the AVHRR satellite and to validate SeaWiFS ocean color products.

  5. Vertical profiles of aerosol volume from high-spectral-resolution infrared transmission measurements. I. Methodology.

    PubMed

    Eldering, A; Irion, F W; Chang, A Y; Gunson, M R; Mills, F P; Steele, H M

    2001-06-20

    The wavelength-dependent aerosol extinction in the 800-1250-cm(-1) region has been derived from ATMOS (atmospheric trace molecule spectroscopy) high-spectral-resolution IR transmission measurements. Using models of aerosol and cloud extinction, we have performed weighted nonlinear least-squares fitting to determine the aerosol-volume columns and vertical profiles of stratospheric sulfate aerosol and cirrus cloud volume. Modeled extinction by use of cold-temperature aerosol optical constants for a 70-80% sulfuric-acid-water solution shows good agreement with the measurements, and the derived aerosol volumes for a 1992 occultation are consistent with data from other experiments after the eruption of Mt. Pinatubo. The retrieved sulfuric acid aerosol-volume profiles are insensitive to the aerosol-size distribution and somewhat sensitive to the set of optical constants used. Data from the nonspherical cirrus extinction model agree well with a 1994 mid-latitude measurement indicating the presence of cirrus clouds at the tropopause.

  6. Assessment of Error in Aerosol Optical Depth Measured by AERONET Due to Aerosol Forward Scattering

    NASA Technical Reports Server (NTRS)

    Sinyuk, Alexander; Holben, Brent N.; Smirnov, Alexander; Eck, Thomas F.; Slustsker, Ilya; Schafer, Joel S.; Giles, David M.; Sorokin, Michail

    2013-01-01

    We present an analysis of the effect of aerosol forward scattering on the accuracy of aerosol optical depth (AOD) measured by CIMEL Sun photometers. The effect is quantified in terms of AOD and solar zenith angle using radiative transfer modeling. The analysis is based on aerosol size distributions derived from multi-year climatologies of AERONET aerosol retrievals. The study shows that the modeled error is lower than AOD calibration uncertainty (0.01) for the vast majority of AERONET level 2 observations, 99.53%. Only 0.47% of the AERONET database corresponding mostly to dust aerosol with high AOD and low solar elevations has larger biases. We also show that observations with extreme reductions in direct solar irradiance do not contribute to level 2 AOD due to low Sun photometer digital counts below a quality control cutoff threshold.

  7. Assessment of error in aerosol optical depth measured by AERONET due to aerosol forward scattering

    NASA Astrophysics Data System (ADS)

    Sinyuk, Alexander; Holben, Brent N.; Smirnov, Alexander; Eck, Thomas F.; Slutsker, Ilya; Schafer, Joel S.; Giles, David M.; Sorokin, Mikhail

    2012-12-01

    We present an analysis of the effect of aerosol forward scattering on the accuracy of aerosol optical depth (AOD) measured by CIMEL Sun photometers. The effect is quantified in terms of AOD and solar zenith angle using radiative transfer modeling. The analysis is based on aerosol size distributions derived from multi-year climatologies of AERONET aerosol retrievals. The study shows that the modeled error is lower than AOD calibration uncertainty (0.01) for the vast majority of AERONET level 2 observations, ∼99.53%. Only ∼0.47% of the AERONET database corresponding mostly to dust aerosol with high AOD and low solar elevations has larger biases. We also show that observations with extreme reductions in direct solar irradiance do not contribute to level 2 AOD due to low Sun photometer digital counts below a quality control cutoff threshold.

  8. Aerosol properties derived from spectral actinic flux measurements

    NASA Astrophysics Data System (ADS)

    Stark, H.; Schmidt, K. S.; Pilewskie, P.; Cozic, J.; Wollny, A. G.; Brock, C. A.; Baynard, T.; Lack, D.; Parrish, D. D.; Fehsenfeld, F. C.

    2008-12-01

    Measurement of aerosol properties is very important for understanding climate change. Aerosol optical properties influence solar radiation throughout the troposphere. According to the Working Group I report of the intergovernmental panel for climate change [IPCC, 2007], aerosols have a direct radiative forcing of - 0.5±0.4 W/m2 with a medium to low level of scientific understanding. This relatively large uncertainty indicates the need for more frequent and precise measurements of aerosol properties. We will show how actinic flux measurements can be used to derive important optical aerosol parameters such as aerosol optical thickness and depth, surface albedo, angstrom exponent, radiative forcing by clouds and aerosols, aerosol extinction, and others. The instrument used for this study is a combination of two spectroradiometers measuring actinic flux in the ultraviolet and visible radiation range from 280 to 690 nm with a resolution of 1 nm. Actinic flux is measured as the radiation incident on a spherical surface with sensitivity independent of direction. In contrast, irradiance is measured as the radiation incident on a plane surface, which depends on the cosine of the incident angle. Our goal is to assess the capabilities of using spectral actinic flux measurements to derive various aerosol properties. Here we will compare 1) actinic flux measurements to irradiance measurements from the spectral solar flux radiometer (SSFR), 2) derived aerosol size distributions with measurements from a white light optical particle counter (WLOPC) and ultra high sensitivity aerosol size spectrometer (UHSAS), and 3) derived aerosol optical extinction with measurements from a cavity ringdown aerosol extinction spectrometer (CRD-AES). These comparisons will utilize data from three recent field campaigns over New England and the Atlantic Ocean (ICARTT 2004), Texas and the Gulf of Mexico during (TexAQS/GoMACCS 2006), and Alaska and the Arctic Ocean (ARCPAC 2008) when the instruments

  9. Huygens Probe Aerosol Collector Pyrolyser Experiment

    NASA Astrophysics Data System (ADS)

    Israel, M.; Cabane, J.-F.; Brun, G.; Niemann, S.; Way, H.; Riedler, W.; Steller, M.; Raulin, F.; Coscia, D.

    2002-07-01

    ACP's main objective is the chemical analysis of the aerosols in Titan's atmosphere. For this purpose, it will sample the aerosols during descent and prepare the collected matter (by evaporation, pyrolysis and gas products transfer) for analysis by the Huygens Gas Chromatograph Mass Spectrometer (GCMS). A sampling system is required for sampling the aerosols in the 135-32 km and 22-17 km altitude regions of Titan's atmosphere. A pump unit is used to force the gas flow through a filter. In its sampling position, the filter front face extends a few mm beyond the inlet tube. The oven is a pyrolysis furnace where a heating element can heat the filter and hence the sampled aerosols to 250°C or 600°C. The oven contains the filter, which has a thimble-like shape (height 28 mm). For transferring effluent gas and pyrolysis products to GCMS, the carrier gas is a labeled nitrogen 15N2, to avoid unwanted secondary reactions with Titan's atmospheric nitrogen. Aeraulic tests under cold temperature conditions were conducted by using a cold gas test system developed by ONERA. The objective of the test was to demonstrate the functional ability of the instrument during the descent of the probe and to understand its thermal behavior, that is to test the performance of all its components, pump unit and mechanisms. In order to validate ACP's scientific performance, pyrolysis tests were conducted at LISA on solid phase material synthesized from experimental simulation. The chromatogram obtained by GCMS analysis shows many organic compounds. Some GC peaks appear clearly from the total mass spectra, with specific ions well identified thanks to the very high sensitivity of the mass spectrometer. The program selected for calibrating the flight model is directly linked to the GCMS calibration plan. In order not to pollute the two flight models with products of solid samples such as tholins, we excluded any direct pyrolysis tests through the ACP oven during the first phase of the

  10. Huygens Probe Aerosol Collector Pyrolyser Experiment

    NASA Astrophysics Data System (ADS)

    Israel, G.; Cabane, M.; Brun, J.-F.; Niemann, H.; Way, S.; Riedler, W.; Steller, M.; Raulin, F.; Coscia, D.

    2002-07-01

    ACP's main objective is the chemical analysis of the aerosols in Titan's atmosphere. For this purpose, it will sample the aerosols during descent and prepare the collected matter (by evaporation, pyrolysis and gas products transfer) for analysis by the Huygens Gas Chromatograph Mass Spectrometer (GCMS). A sampling system is required for sampling the aerosols in the 135'32 km and 22'17 km altitude regions of Titan's atmosphere. A pump unit is used to force the gas flow through a filter. In its sampling position, the filter front face extends a few mm beyond the inlet tube. The oven is a pyrolysis furnace where a heating element can heat the filter and hence the sampled aerosols to 250 °C or 600 °C. The oven contains the filter, which has a thimble-like shape (height 28 mm). For transferring effluent gas and pyrolysis products to GCMS, the carrier gas is a labeled nitrogen 15N2, to avoid unwanted secondary reactions with Titan's atmospheric nitrogen. Aeraulic tests under cold temperature conditions were conducted by using a cold gas test system developed by ONERA. The objective of the test was to demonstrate the functional ability of the instrument during the descent of the probe and to understand its thermal behavior, that is to test the performance of all its components, pump unit and mechanisms. In order to validate ACP's scientific performance, pyrolysis tests were conducted at LISA on solid phase material synthesized from experimental simulation. The chromatogram obtained by GCMS analysis shows many organic compounds. Some GC peaks appear clearly from the total mass spectra, with specific ions well identified thanks to the very high sensitivity of the mass spectrometer. The program selected for calibrating the flight model is directly linked to the GCMS calibration plan. In order not to pollute the two flight models with products of solid samples such as tholins, we excluded any direct pyrolysis tests through the ACP oven during the first phase of the

  11. Aerosol optical properties in the ABL over arctic sea ice from airborne aerosol lidar measurements

    NASA Astrophysics Data System (ADS)

    Schmidt, Lukas; Neuber, Roland; Ritter, Christoph; Maturilli, Marion; Dethloff, Klaus; Herber, Andreas

    2014-05-01

    Between 2009 and 2013 aerosols, sea ice properties and meteorological variables were measured during several airborne campaigns covering a wide range of the western Arctic Ocean. The campaigns were carried out with the aircraft Polar 5 of the German Alfred-Wegener-Institute (AWI) during spring and summer periods. Optical properties of accumulation mode aerosol and clouds were measured with the nadir looking AMALi aerosol lidar covering the atmospheric boundary layer and the free troposphere up to 3000m, while dropsondes provided coincident vertical profiles of meteorological quantities. Based on these data we discuss the vertical distribution of aerosol backscatter in and above the atmospheric boundary layer and its dependence on relative humidity, dynamics and underlying sea ice properties. We analyze vertical profiles of lidar and coincident dropsonde measurements from various locations in the European and Canadian Arctic from spring and summer campaigns. Sea ice cover is derived from modis satellite and aircraft onboard camera images. The aerosol load in the arctic atmospheric boundary layer shows a high variability. Various meteorological parameters and in particular boundary layer properties are discussed with their respective influence on aerosol features. To investigate the effect of the frequency and size of open water patches on aerosol properties, we relate the profiles to the sea ice properties influencing the atmosphere in the upwind region.

  12. Development and Characterization of a Thermodenuder for Aerosol Volatility Measurements

    SciTech Connect

    Dr. Timothy Onasch

    2009-09-09

    This SBIR Phase I project addressed the critical need for improved characterization of carbonaceous aerosol species in the atmosphere. The proposed work focused on the development of a thermodenuder (TD) system capable of systematically measuring volatility profiles of primary and secondary organic aerosol species and providing insight into the effects of absorbing and nonabsorbing organic coatings on particle absorption properties. This work provided the fundamental framework for the generation of essential information needed for improved predictions of ambient aerosol loadings and radiative properties by atmospheric chemistry models. As part of this work, Aerodyne Research, Inc. (ARI) continued to develop and test, with the final objective of commercialization, an improved thermodenuder system that can be used in series with any aerosol instrument or suite of instruments (e.g., aerosol mass spectrometers-AMS, scanning mobility particle sizers-SMPS, photoacoustic absorption spectrometers-PAS, etc.) to obtain aerosol chemical, physical, and optical properties as a function of particle volatility. In particular, we provided the proof of concept for the direct coupling of our improved TD design with a full microphysical model to obtain volatility profiles for different organic aerosol components and to allow for meaningful comparisons between different TD-derived aerosol measurements. In a TD, particles are passed through a heated zone and a denuding (activated charcoal) zone to remove semi-volatile material. Changes in particle size, number concentration, optical absorption, and chemical composition are subsequently detected with aerosol instrumentation. The aerosol volatility profiles provided by the TD will strengthen organic aerosol emission inventories, provide further insight into secondary aerosol formation mechanisms, and provide an important measure of particle absorption (including brown carbon contributions and identification, and absorption enhancements

  13. Measurement of size distributions of a coagulating aerosol. [Calcium carbonate

    SciTech Connect

    Loos, H.G.

    1984-05-01

    Measurements have been performed for the determination of the size distribution of a coagulating ultrafine aerosol over a time interval of up to about 30 min. The aerosol was contained in a balloon with an initial volume of 60 l subject to a temperature inversion for the purpose of quenching the free convection and thereby diminishing the aerosol loss to the balloon wall. The aerosol size distribution was measured with the TSI electrostatic aerosol classifier hooked up to a TSI aerosol electrometer. The initial aerosol had an average diameter of about 12 nm. Measurements were taken by computer at a rate of 1 measurement cycle every 3 s; 1 cycle consists of a measurement of time, and burst measurements of electrometer current, classifier rod voltage, 3 flow rates, and 5 temperatures, followed by the calculation of averages and standard deviations, and storage of the results in a data string. The TSI instruments have been modified to permit the automatic computer reading of the parameters mentioned above. A multiplexer has been built to allow the multiplet data to be measured by a single system voltmeter. Channel switching in the multiplexer can be done either automatically by using the ''delay'' signal emitted by the system voltmeter every time it makes a reading or by software control through the 16-bit parallel interface of the computer.

  14. Aerosol Spectral Radiative Forcing Efficiency from Airborne Measurements During Multiple Field Missions

    NASA Astrophysics Data System (ADS)

    Schmidt, S.; Leblanc, S. E.; Pilewskie, P.; Redemann, J.; Hostetler, C. A.; Ferrare, R. A.; Hair, J. W.

    2012-12-01

    Measurements of shortwave spectral irradiance in conjunction with measurements of aerosol optical depth are used to determine the direct aerosol radiative forcing for various different regions and missions. To better compare cases with different air masses and solar geometry, we use the concept of top-of-layer and bottom-of-layer relative forcing efficiency. The aerosol layers were sampled from aircraft during several field campaigns, including the Megacity Initiative: Local and Global Research Observations (MILAGRO, Mexico, 2006); the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS, Alaska and Alberta, 2008), Research at the Nexus of Air Quality and Climate Change (CalNex, California, 2010); and the Deep Convective Clouds and Chemistry Experiment (DC3, central US, 2012). We show that the spectral shape of the relative forcing efficiency is similar for these aerosol layers regardless of the aerosol type. The spectral relative forcing efficiency at any one wavelength for the majority of the cases is constrained within a span of 20% per unit of midvisible aerosol optical depth. Single scattering albedo, asymmetry parameter, and surface albedo are secondary products for the various methods used to determine aerosol radiative forcing. Using these, we determine the diurnally averaged spectral and broadband top-of-atmosphere and surface radiative forcing efficiency for the various different aerosol types and surface conditions.

  15. Workplace aerosol mass concentration measurement using optical particle counters.

    PubMed

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

    2012-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Pagowski, Mariusz; Grell, Georg A.

    2011-11-01

    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.

  18. 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.

  19. Measurements of Hygroscopicity- and Size-Resolved Sea Spray Aerosol

    NASA Astrophysics Data System (ADS)

    Phillips, B.; Dawson, K. W.; Royalty, T. M.; Reed, R. E.; Petters, M.; Meskhidze, N.

    2015-12-01

    Atmospheric aerosols play a central role in many environmental processes by influencing the Earth's radiative balance, tropospheric chemistry, clouds, biogeochemical cycles, and visibility as well as adversely impacting human health. Based on their origin, atmospheric aerosols can be defined as anthropogenic or natural. Recent studies have shown that a large fraction of uncertainty in the radiative effects of anthropogenic aerosols is related to uncertainty in natural—background—aerosols. Marine aerosols are of particular interest due to the abundance of oceans covering the Earth's surface. Despite their importance, limited information is currently available for size- and composition-resolved marine aerosol emission fluxes. Our group has designed and built an instrument for measuring the size- and hygroscopicity-resolved sea spray aerosol fluxes. The instrument was first deployed during spring 2015 at the end of the 560 m pier of the US Army Corps of Engineers' Field Research Facility in Duck, NC. Measurements include 200 nm-sized diameter growth factor (hygroscopicity) distributions, sea spray particle flux measurements, and total sub-micron sized aerosol concentration. Ancillary ocean data includes salinity, pH, sea surface temperature, dissolved oxygen content, and relative fluorescence (proxy for [Chl-a]). Hygroscopicity distribution measurements show two broad peaks, one indicative of organics and sulfates and another suggestive of sea salt. The fraction of 200 nm-sized salt particles having hygroscopicity similar to that of sea-spray aerosol contributes up to ~24% of the distribution on days with high-speed onshore winds and up to ~3% on calm days with winds blowing from the continent. However, the total concentration of sea-spray-like particles originating from offshore versus onshore winds was relatively similar. Changes in the relative contribution of sea-salt to number concentration were caused by a concomitant changes in total aerosol concentration

  20. 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%.

  1. 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%.

  2. Observations of Saharan Aerosols: Results of ECLATS Field Experiment. Part I: Optical Thicknesses and Aerosol Size Distributions.

    NASA Astrophysics Data System (ADS)

    Fouquart, Y.; Bonnel, B.; Chaoui Roquai, M.; Santer, R.; Cerf, A.

    1987-01-01

    A series of ground-based and airborne observations of desert aerosols, the ECLATS experiment was carried out in December 1980 in the vicinity of Niamey (Niger). This paper deals with aerosol optical thicknesses and size distributions derived from (i) in situ measurements using singe particle optical counters (a Kratel and a Knollenberg FSSP), (ii) a ground-based cascade impactor, and (iii) ground-based measurements of the spectral variation of the sober extinction.During the experiment, aerosol optical thicknesses (at 550 nm) varied from 0.20 on very clear days to 1.5 during a so-called `dry haze' episode.Comparisons between size distributions derived from in situ measurements from ground-based cascade impactor, and from inversion of the spectral optical thicknesses, showed that the optical counters drastically underestimated the concentration of small (r<0.5 m) particles It was shown that the occurrence of a `dry haze' episode was characterized by a large increase (an order of magnitude in this particular case) of the intermediate particles (r0.5 m), whereas the concentration in very (r<0.2 m) and large (r>1 m) particles remained roughly constant.

  3. Aerosol classification using EARLINET measurements for an intensive observational period

    NASA Astrophysics Data System (ADS)

    Papagiannopoulos, Nikolaos; Mona, Lucia; Pappalardo, Gelsomina

    2016-04-01

    ACTRIS (Aerosols, Clouds and Trace gases Research Infrastructure Network) organized an intensive observation period during summer 2012. This campaign aimed at the provision of advanced observations of physical and chemical aerosol properties, at the delivery of information about the 3D distribution of European atmospheric aerosols, and at the monitoring of Saharan dust intrusions events. EARLINET (European Aerosol Research Lidar Network) participated in the ACTRIS campaign through the addition of measurements according to the EARLINET schedule as well as daily lidar-profiling measurements around sunset by 11 selected lidar stations for the period from 8 June - 17 July. EARLINET observations during this almost two-month period are used to characterize the optical properties and vertical distribution of long-range transported aerosol over the broader area of Mediterranean basin. The lidar measurements of aerosol intensive parameters (lidar ratio, depolarization, Angstrom exponents) are shown to vary with location and aerosol type. A methodology based on EARLINET observations of frequently observed aerosol types is used to classify aerosols into seven separate types. The summertime Mediterranean basin is prone to African dust aerosols. Two major dust events were studied. The first episode occurred from the 18 to 21 of the June and the second one lasted from 28 June to 6 July. The lidar ratio within the dust layer was found to be wavelength independent with mean values of 58±14 sr at 355 nm and 57±11 sr at 532 nm. For the particle linear depolarization ratio, mean values of 0.27±0.04 at 532 nm have been found. Acknowledgements. The financial support for EARLINET in the ACTRIS Research Infrastructure Project by the European Union's Horizon 2020 research and innovation programme under grant agreement no. 654169 and previously under grant agreement no. 262254 in the Seventh Framework Programme (FP7/2007-2013) is gratefully acknowledged.

  4. Comparison of Modeled Backscatter using Measured Aerosol Microphysics with Focused CW Lidar Data over Pacific

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

    During NASA's GLObal Backscatter Experiment (GLOBE) II flight mission over the Pacific Ocean in May-June 1990, extensive aerosol backscatter data sets from two continuous wave, focused CO2 Doppler lidars and an aerosol microphysics data set from a laser optical particle counter (LOPC) were obtained. Changes in aerosol loading in various air masses with associated changes in chemical composition, from sulfuric acid and sulfates to dustlike crustal material, significantly affected aerosol backscatter, causing variation of about 3 to 4 orders of magnitude. Some of the significant backscatter features encountered in different air masses were the low backscatter in subtropical air with even lower values in the tropics near the Intertropical Convergence Zone (ITCZ), highly variable backscatter in the ITCZ, mid-tropospheric aerosol backscatter background mode, and high backscatter in an Asian dust plume off the Japanese coast. Differences in aerosol composition and backscatter for northern and southern hemisphere also were observed. Using the LOPC measurements of physical and chemical aerosol properties, we determined the complex refractive index from three different aerosol mixture models to calculate backscatter. These values provided a well-defined envelope of modeled backscatter for various atmospheric conditions, giving good agreement with the lidar data over a horizontal sampling of approximately 18000 km in the mid-troposphere.

  5. Measuring Aerosol Optical Depth (AOD) and Aerosol Profiles Simultaneously with a Camera Lidar

    NASA Astrophysics Data System (ADS)

    Barnes, John; Pipes, Robert; Sharma, Nimmi C. P.

    2016-06-01

    CLidar or camera lidar is a simple, inexpensive technique to measure nighttime tropospheric aerosol profiles. Stars in the raw data images used in the CLidar analysis can also be used to calculate aerosol optical depth simultaneously. A single star can be used with the Langley method or multiple star pairs can be used to reduce the error. The estimated error from data taken under clear sky conditions at Mauna Loa Observatory is approximately +/- 0.01.

  6. A balloon-borne aerosol spectrometer for high altitude low aerosol concentration measurements

    SciTech Connect

    Brown, G.S. ); Weiss, R.E. )

    1990-08-01

    Funded by Air Force Wright Aeronautical Laboratory, a new balloon-borne high altitude aerosol spectrometer, for the measurement of cirrus cloud ice crystals, has been developed and successfully flown by Sandia National Laboratories and Radiance Research. This report (1) details the aerosol spectrometer design and construction, (2) discusses data transmission and decoding, (3) presents data collected on three Florida flights in tables and plots. 2 refs., 11 figs., 3 tabs.

  7. 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.

  8. Airborne Lidar Measurements of Aerosol Optical Properties During SAFARI-2000

    NASA Technical Reports Server (NTRS)

    McGill, M. J.; Hlavka, D. L.; Hart, W. D.; Welton, E. J.; Campbell, J. R.; Starr, David OC. (Technical Monitor)

    2002-01-01

    The Cloud Physics Lidar (CPL) operated onboard the NASA ER-2 high altitude aircraft during the SAFARI-2000 field campaign. The CPL provided high spatial resolution measurements of aerosol optical properties at both 1064 nm and 532 nm. We present here results of planetary boundary layer (PBL) aerosol optical depth analysis and profiles of aerosol extinction. Variation of optical depth and extinction are examined as a function of regional location. The wide-scale aerosol mapping obtained by the CPL is a unique data set that will aid in future studies of aerosol transport. Comparisons between the airborne CPL and ground-based MicroPulse Lidar Network (MPL-Net) sites are shown to have good agreement.

  9. Overview of the Megacity Aerosol Experiment: Mexico City (MAX-Mex)

    NASA Astrophysics Data System (ADS)

    Gaffney, J. S.

    2007-05-01

    Tropospheric aerosols can play an important role the radiative balance of the globe. This is due to their ability to scatter and absorb solar radiation. The sign of this forcing will depend on their chemical composition and size, their lifetimes, and position in the atmosphere. Major sources of aerosols are now coming from megacities: Cities with more than 10 million population. As part of the MILAGRO campaign, the Megacity Aerosol Experiment: Mexico City was conducted by the Atmospheric Science Program of the Climate Change Research Division of the Department of Energy in collaboration with the scientists supported by NSF, NASA, and Mexican agencies. The preliminary results of the study will be overviewed and highlights of the efforts from both ground based and airborne measurements presented. Data from the study confirm that the megacity plumes are significant sources of both primary and secondary aerosols into the regional scale, and black carbon and secondary aerosols are contributing to single scattering albedos in the Valley of Mexico and downwind that are substantially reduced when compared to other areas (such as the eastern United States). The potential of biomass burning as well as megacity plumes contributing to a decrease in the aerosol single scattering albedos (aerosol direct effects) on regional scales will be discussed. This work was performed as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City under the support of the Atmospheric Science Program. "This researchwas supported by the Office of Science (BER), U. S. Department of Energy, Grant No. DE-FG02-07ER64328.

  10. Airborne Cavity Ring-Down Measurement of Aerosol Extinction and Scattering During the Aerosol IOP

    NASA Technical Reports Server (NTRS)

    Strawa, A. W.; Ricci, K.; Provencal, R.; Schmid, B.; Covert, D.; Elleman, R.; Arnott, P.

    2003-01-01

    Large uncertainties in the effects of aerosols on climate require improved in-situ measurements of extinction coefficient and single-scattering albedo. This paper describes preliminary results from Cadenza, a new continuous wave cavity ring-down (CW-CRD) instrument designed to address these uncertainties. Cadenza measures the aerosol extinction coefficient for 675 nm and 1550 nm light, and simultaneously measures the scattering coefficient at 675 nm. In the past year Cadenza was deployed in the Asian Dust Above Monterey (ADAM) and DOE Aerosol Intensive Operating Period (IOP) field projects. During these flights Cadenza produced measurements of aerosol extinction in the range from 0.2 to 300 Mm-1 with an estimated precision of 0.1 Min-1 for 1550 nm light and 0.2 Mm-1 for 675 nm light. Cadenza data from the ADAM and Aerosol IOP missions compared favorably with data from the other instruments aboard the CIRPAS Twin Otter aircraft and participating in those projects.= We present comparisons between the Cadenza measurements and those friom a TSI nephelometer, Particle Soot Absorption Photometer (PSAP), and the AATS 14 sun-photometer. Measurements of the optical properties of smoke and dust plumes sampled during these campaigns are presented and estimates of heating rates due to these plumes are made.

  11. LASE Measurements of Water Vapor, Aerosol, and Cloud Distributions in Saharan Air Layers and Tropical Disturbances

    NASA Technical Reports Server (NTRS)

    Ismail, Syed; Ferrare, Richard A.; Browell, Edward V.; Kooi, Susan A.; Dunion, Jason P.; Heymsfield, Gerry; Notari, Anthony; Butler, Carolyn F.; Burton, Sharon; Fenn, Marta; Krishnamurti, T. N.; Chen, Gao; Anderson, Bruce

    2010-01-01

    LASE (Lidar Atmospheric Sensing Experiment) on-board the NASA DC-8 measured high resolution profiles of water vapor and aerosols, and cloud distributions in 14 flights over the eastern North Atlantic during the NAMMA (NASA African Monsoon Multidisciplinary Analyses) field experiment. These measurements were used to study African easterly waves (AEWs), tropical cyclones (TCs), and the Saharan Air Layer(s) (SAL). Interactions between the SAL and tropical air were observed during the early stages of the TC development. These LASE measurements represent the first simultaneous water vapor and aerosol lidar measurements to study the SAL and its impact on AEWs and TCs. Examples of profile measurements of aerosol scattering ratios, aerosol extinction coefficients, aerosol optical thickness, water vapor mixing ratios, RH, and temperature are presented to illustrate their characteristics in SAL, convection, and clear air regions. LASE data suggest that the SAL suppresses low-altitude convection at the convection-SAL interface region. Mid-level convection associated with the AEW and transport are likely responsible for high water vapor content observed in the southern regions of the SAL on August 20, 2008. This interaction is responsible for the transfer of about 7 x 10(exp 15) J latent heat energy within a day to the SAL. Measurements of lidar extinction-to-backscatter ratios in the range 36+/-5 to 45+/-5 are within the range of measurements from other lidar measurements of dust. LASE aerosol extinction and water vapor profiles are validated by comparison with onboard in situ aerosol measurements and GPS dropsonde water vapor soundings, respectively.

  12. 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.

  13. Measurements and Modeling of Aerosol Absorption and Single Scattering Albedo at Ambient Relative Hum

    NASA Technical Reports Server (NTRS)

    Redemann, J.; Russell, P. B.; Hamill, P.

    2000-01-01

    Uncertainties in the aerosol single scattering albedo have been identified to be an important source of errors in current large-scale model estimates of the direct aerosol radiative forcing of climate. A number of investigators have obtained estimates of the single scattering albedo from a variety of remote sensing and in situ measurements during aerosol field experiments. During the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX, 1996) for example, estimates of the aerosol single scattering albedo were obtained (1) as a best-fit parameter in comparing radiative flux changes measured by airborne pyranometer to those computed from independently measured aerosol properties; (2) from estimates of the aerosol complex index of refraction derived using a combination of airborne sunphotometer, lidar backscatter and in situ size distribution measurements; and (3) from airborne measurements of aerosol scattering and absorption using nephelometers and absorption photometers. In this paper, we briefly compare the results of the latter two methods for two TARFOX case studies, since those techniques provide height-resolved information about the aerosol single scattering albedo. Estimates of the aerosol single scattering albedo from nephelometer and absorption photometer measurements require knowledge of the scattering and absorption humidification (i.e., the increase in these properties in response to an increase in ambient relative humidity), since both measurements are usually carried out at a relative humidity different from the ambient atmosphere. In principle, the scattering humidification factor can be measured, but there is currently no technique widely available to measure the absorption of an aerosol sample as a function of relative humidity. Frequently, for lack of better knowledge, the absorption humidification is assumed to be unity (meaning that there is no change in aerosol absorption due to an increase in ambient relative humidity). This

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

    NASA Technical Reports Server (NTRS)

    Grams, G. W.

    1969-01-01

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

  15. A Global Survey of Shipboard Measurements of Aerosol Optical Properties over the Oceans

    NASA Astrophysics Data System (ADS)

    Miller, M. A.; Reynolds, R. M.; Quinn, P.; Bartholomew, M. J.

    2001-12-01

    numerous cruises of opportunity (over 20) and is semi-permanently deployed on several operational research vessels. The data base of cruises has reasonable global coverage and the current FRSR data base contains years of data. In addition to routine cruises, the FRSR database includes data from the following field experiments: Aerosols99, INDOEX, Nauru99, and ACE-Asia. The FRSR data base have been analyzed for the purpose of classifying the various aerosol regimes over the world's oceans and quantifying the aerosol optical properties in these regimes. Uncertainties in the measurements have been quantified and are used as filtering criteria. Data from the instrument, after significant processing, are combined with aerosol chemical classifications, when available, to provide a unique view of aerosol structure over the world's oceans. Different aerosol regimes have been identified and their characteristics determined from the FRSR measurements. The FRSR can distinguish differences between the aerosol radiative properties, namely the aerosol optical thickness, the angstrom exponent, and the diffuse irradiance, in different aerosol regimes. Differences in the aerosol characteristics in different regimes are delineated in the FRSR data and interesting patterns are documented.

  16. Airborne Sun Photometer Measurements of Aerosol Optical Depth during SOLVE II: Comparison with SAGE III and POAM III Measurements

    NASA Technical Reports Server (NTRS)

    Russell, P.; Livingston, J.; Schmid, B.; Eilers, J.; Kolyer, R.; Redemann, J.; Yee, J.-H.; Trepte, C.; Thomason, L.; Zawodny, J.

    2003-01-01

    The 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was operated aboard the NASA DC-8 during the Second SAGE III Ozone Loss and Validation Experiment (SOLVE II) and obtained successful measurements during the sunlit segments of eight science flights. These included six flights out of Kiruna, Sweden, one flight out of NASA Dryden Flight Research Center (DFRC), and the Kiruna-DFRC return transit flight. Values of spectral aerosol optical depth (AOD), columnar ozone and columnar water vapor have been derived from the AATS-14 measurements. In this paper, we focus on AATS-14 AOD data. In particular, we compare AATS-14 AOD spectra with temporally and spatially near-coincident measurements by the Stratospheric Aerosol and Gas Experiment III (SAGE III) and the Polar Ozone and Aerosol Measurement III (POAM III) satellite sensors. We examine the effect on retrieved AOD of uncertainties in relative optical airmass (the ratio of AOD along the instrument-to-sun slant path to that along the vertical path) at large solar zenith angles. Airmass uncertainties result fiom uncertainties in requisite assumed vertical profiles of aerosol extinction due to inhomogeneity along the viewing path or simply to lack of available data. We also compare AATS-14 slant path solar transmission measurements with coincident measurements acquired from the DC-8 by the NASA Langley Research Center Gas and Aerosol Measurement Sensor (GAMS).

  17. International Workshop on Stratospheric Aerosols: Measurements, Properties, and Effects

    NASA Technical Reports Server (NTRS)

    Pueschel, Rudolf F. (Editor)

    1991-01-01

    Following a mandate by the International Aerosol Climatology Program under the auspices of International Association of Meteorology and Atmospheric Physics International Radiation Commission, 45 scientists from five nations convened to discuss relevant issues associated with the measurement, properties, and effects of stratospheric aerosols. A summary is presented of the discussions on formation and evolution, transport and fate, effects on climate, role in heterogeneous chemistry, and validation of lidar and satellite remote sensing of stratospheric aerosols. Measurements are recommended of the natural (background) and the volcanically enhanced aerosol (sulfuric acid and silica particles), the exhaust of shuttle, civil aviation and supersonic aircraft operations (alumina, soot, and ice particles), and polar stratospheric clouds (ice, condensed nitric and hydrochloric acids).

  18. Multiwavelength Comparison of Modeled and Measured Remote Tropospheric Aerosol Backscatter Over Pacific Ocean

    NASA Technical Reports Server (NTRS)

    Cutten, D. R.; Pueschel, R. F.; Srivastava, V.; Clarke, A. D.; Rothermel, J.; Spinhirne, J. D.; Menzies, R. T.

    1996-01-01

    Aerosol concentrations and size distributions in the middle and upper troposphere over the remote Pacific Ocean were measured with a forward scattering spectrometer probe (FSSP) on the NASA DC-8 aircraft during NASA's Global Backscatter Experiment (GLOBE) in May-June 1990. The FSSP size channels were recalibrated based on refractive index estimates from flight-level aerosol volatility measurements with a collocated laser optical particle counter (LOPC). The recalibrated FSSP size distributions were averaged over 100-s intervals, fitted with lo-normal distributions and used to calculate aerosol backscatter coefficients at selected wavelengths. The FSSP-derived backscatter estimates were averaged over 300-s intervals to reduce large random fluctuations. The smoothed FSSP aerosol backscatter coefficients were then compared with LOPC-derived backscatter values and with backscatter measured at or near flight level from four lidar systems operating at 0.53, 1.06, 9.11, 9.25, and 10.59 micrometers. Agreement between FSSP-derived and lidar-measured backscatter was generally best at flight level in homogeneous aerosol fields and at high backscatter values. FSSP data often underestimated low backscatter values especially at the longer wavelengths due to poor counting statistics for larger particles (greater than 0.8 micrometers diameter) that usually dominate aerosol backscatter at these wavelengths. FSSP data also underestimated backscatter at shorter wavelengths when particles smaller than the FSSP lower cutoff diameter (0.35 micrometers) made significant contributions to the total backscatter.

  19. 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.

  20. Comparative Optical Measurements of Airspeed and Aerosols on a DC-8 Aircraft

    NASA Technical Reports Server (NTRS)

    Bogue, Rodney; McGann, Rick; Wagener, Thomas; Abbiss, John; Smart, Anthony

    1997-01-01

    NASA Dryden supported a cooperative flight test program on the NASA DC-8 aircraft in November 1993. This program evaluated optical airspeed and aerosol measurement techniques. Three brassboard optical systems were tested. Two were laser Doppler systems designed to measure free-stream-referenced airspeed. The third system was designed to characterize the natural aerosol statistics and airspeed. These systems relied on optical backscatter from natural aerosols for operation. The DC-8 aircraft carried instrumentation that provided real-time flight situation information and reference data on the aerosol environment. This test is believed to be the first to include multiple optical airspeed systems on the same carrier aircraft, so performance could be directly compared. During 23 hr of flight, a broad range of atmospheric conditions was encountered, including aerosol-rich layers, visible clouds, and unusually clean (aerosol-poor) regions. Substantial amounts of data were obtained. Important insights regarding the use of laser-based systems of this type in an aircraft environment were gained. This paper describes the sensors used and flight operations conducted to support the experiments. The paper also briefly describes the general results of the experiments.

  1. 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.

  2. Ground-based Network and Supersite Measurements for Studying Aerosol Properties and Aerosol-Cloud Interactions

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee; Holben, Brent N.

    2008-01-01

    From radiometric principles, it is expected that the retrieved properties of extensive aerosols and clouds from reflected/emitted measurements by satellite (and/or aircraft) should be consistent with those retrieved from transmitted/emitted radiance observed at the surface. Although space-borne remote sensing observations contain large spatial domain, they are often plagued by contamination of surface signatures. Thus, ground-based in-situ and remote-sensing measurements, where signals come directly from atmospheric constituents, the sun, and the Earth-atmosphere interactions, provide additional information content for comparisons that confirm quantitatively the usefulness of the integrated surface, aircraft, and satellite datasets. The development and deployment of AERONET (AErosol RObotic NETwork) sunphotometer network and SMART-COMMIT (Surface-sensing Measurements for Atmospheric Radiative Transfer - Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile supersite are aimed for the optimal utilization of collocated ground-based observations as constraints to yield higher fidelity satellite retrievals and to determine any sampling bias due to target conditions. To characterize the regional natural and anthropogenic aerosols, AERONET is an internationally federated network of unique sunphotometry that contains more than 250 permanent sites worldwide. Since 1993, there are more than 480 million aerosol optical depth observations and about 15 sites have continuous records longer than 10 years for annual/seasonal trend analyses. To quantify the energetics of the surface-atmosphere system and the atmospheric processes, SMART-COMMIT instrument into three categories: flux radiometer, radiance sensor and in-situ probe. Through participation in many satellite remote-sensing/retrieval and validation projects over eight years, SMART-COMMIT have gradually refine( and been proven vital for field deployment. In this paper, we will demonstrate the

  3. SAGE aerosol measurements. Volume 1: February 21, 1979 to December 31, 1979

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.

    1985-01-01

    The Stratospheric Aerosol and Gas Experiment (SAGE) satellite system, launched on February 18, 1979, provides profiles of aerosol extinction, ozone concentration, and nitrogen dioxide concentration between about 80 N and 80 S. Zonal averages, separated into sunrise and sunset events, and seasonal averages of the aerosol extinction at 1.00 microns and 0.45 microns ratios of the aerosol extinction to the molecular extinction at 1.00 microns, and ratios of the aerosol extinction at 0.45 microns to the aerosol extinction at 1.00 microns are given. The averages for 1979 are shown in tables and in profile and contour plots (as a function of altitude and latitude). In addition, temperature data provided by the National Oceanic and Atmospheric Administration (NOAA) for the time and location of each SAGE measurement are averaged and shown in a similar format. Typical values of the peak aerosol extinction were 0.0001 to 0.0002 km at 1.00 microns depth values for the 1.00 microns channel varied between 0.001 and 0.002 over all latitudes.

  4. Broadband measurements of aerosol extinction in the ultraviolet spectral region

    NASA Astrophysics Data System (ADS)

    Washenfelder, R. A.; Flores, J. M.; Brock, C. A.; Brown, S. S.; Rudich, Y.

    2013-01-01

    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. We describe a new laboratory 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 determined aerosol extinction cross-sections and directly observed Mie scattering resonances for aerosols that are purely scattering (polystyrene latex spheres and ammonium sulfate), slightly absorbing (Suwannee River fulvic acid), and strongly absorbing (nigrosin dye). We describe an approach for retrieving refractive indices as a function of wavelength from the measured extinction cross-sections over the 360-420 nm wavelength region. The retrieved refractive indices for PSL and ammonium sulfate agree within uncertainty with literature values for this spectral region. The refractive index determined for nigrosin is 1.78 (±0.03) + 0.19 (±0.08) i at 360 nm and 1.53 (±0.03) + 0.21 (±0.05) i at 420 nm. The refractive index determined for Suwannee River fulvic acid is 1.71 (±0.02) + 0.07 (±0.06) i at 360 nm and 1.66 (±0.02) + 0.06 (±0.04) i at 420 nm. These laboratory results support the potential for a field instrument capable of determining ambient aerosol optical extinction, average aerosol extinction cross-section, and complex refractive index as a function of wavelength.

  5. Broadband measurements of aerosol extinction in the ultraviolet spectral region

    NASA Astrophysics Data System (ADS)

    Washenfelder, R. A.; Flores, J. M.; Brock, C. A.; Brown, S. S.; Rudich, Y.

    2013-04-01

    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. We describe a new laboratory 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 determined aerosol extinction cross sections and directly observed Mie scattering resonances for aerosols that are purely scattering (polystyrene latex spheres and ammonium sulfate), slightly absorbing (Suwannee River fulvic acid), and strongly absorbing (nigrosin dye). We describe an approach for retrieving refractive indices as a function of wavelength from the measured extinction cross sections over the 360-420 nm wavelength region. The retrieved refractive indices for PSL and ammonium sulfate agree within uncertainty with the literature values for this spectral region. The refractive index determined for nigrosin is 1.78 (± 0.03) + 0.19 (± 0.08)i at 360 nm and 1.63 (± 0.03) + 0.21 (± 0.05)i at 420 nm. The refractive index determined for Suwannee River fulvic acid is 1.71 (± 0.02) + 0.07 (± 0.06)i at 360 nm and 1.66 (± 0.02) + 0.06 (± 0.04)i at 420 nm. These laboratory results support the potential for a field instrument capable of determining ambient aerosol optical extinction, average aerosol extinction cross section, and complex refractive index as a function of wavelength.

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

    NASA Astrophysics Data System (ADS)

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

    2002-05-01

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

  7. Measurement of relative humidity dependent light scattering of aerosols

    NASA Astrophysics Data System (ADS)

    Fierz-Schmidhauser, R.; Zieger, P.; Wehrle, G.; Jefferson, A.; Ogren, J. A.; Baltensperger, U.; Weingartner, E.

    2009-09-01

    Relative humidity (RH) influences the water content of aerosol particles and therefore has an important impact on the particles' ability to scatter visible light. The RH dependence of the particle light scattering coefficient (σsp) is therefore an important measure for climate forcing calculations. We built a humidification system for a nephelometer which allows the measurement of σsp at a defined RH in the range of 40-90%. This RH conditioner consists of a humidifier followed by a dryer, which enables us to measure the hysteresis behavior of deliquescent aerosol particles. In this paper we present the set-up of a new humidified nephelometer, a detailed characterization with well defined laboratory generated aerosols, and a first application in the field by comparing our instrument to another humidified nephelometer. Monodisperse ammonium sulfate and sodium chloride particles were measured at four different dry particle sizes. Agreement between measurement and prediction based on Mie theory was found for both σsp and f(RH)=σsp(RH)/σsp(dry) within the range of uncertainty. The two humidified nephelometers measuring at a rural site in the Black Forest (Germany) often detected different f(RH), probably caused by the aerosol hysteresis behavior: when the aerosol was metastable, therefore was scattering more light, only one instrument detected the higher f(RH).

  8. Measurement of relative humidity dependent light scattering of aerosols

    NASA Astrophysics Data System (ADS)

    Fierz-Schmidhauser, R.; Zieger, P.; Wehrle, G.; Jefferson, A.; Ogren, J. A.; Baltensperger, U.; Weingartner, E.

    2010-01-01

    Relative humidity (RH) influences the water content of aerosol particles and therefore has an important impact on the particles' ability to scatter visible light. The RH dependence of the particle light scattering coefficient (σsp is therefore an important measure for climate forcing calculations. We built a humidification system for a nephelometer which allows the measurement of σsp at a defined RH in the range of 40-90%. This RH conditioner consists of a humidifier followed by a dryer, which enables us to measure the hysteresis behavior of deliquescent aerosol particles. In this paper we present the set-up of a new humidified nephelometer, a detailed characterization with well defined laboratory generated aerosols, and a first application in the field by comparing our instrument to another humidified nephelometer. Monodisperse ammonium sulfate and sodium chloride particles were measured at four different dry particle sizes. Agreement between measurement and prediction based on Mie theory was found for both σsp and f(RH)=σsp(RH)/σsp(dry) within the range of uncertainty. The two humidified nephelometers measuring at a rural site in the Black Forest (Germany) often detected different f(RH), probably caused by the aerosol hysteresis behavior: when the aerosol was metastable, therefore was scattering more light, only one instrument detected the higher f(RH).

  9. Radiative Flux Changes by Aerosols from North America, Europe, and Africa over the Atlantic Ocean: Measurements and Calculations from TARFOX and ACE-2

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Hignett, P.; Livingston, J. M.; Schmid, B.; Chien, A.; Bergstrom, R.; Durkee, P. A.; Hobbs, P. V.; Bates, T. S.; Quinn, P. K.; Condon, Estelle (Technical Monitor)

    1998-01-01

    Aerosol effects on atmospheric radiative fluxes provide a forcing function that is a major source of uncertainty in understanding the past climate and predicting climate change. To help reduce this uncertainty, the 1996 Tropospheric Aerosol Radiative Forcing Experiment (TARFOX) and the 1997 second Aerosol Characterization Experiment (ACE-2) measured the properties and radiative effects of American, European, and African aerosols over the Atlantic. In TARFOX, radiative fluxes and microphysics of the American aerosol were measured from the UK C-130 while optical depth spectra, aerosol composition, and other properties were measured by the University of Washington C-131A and the CIRPAS Pelican. Closure studies show that the measured flux changes agree with those derived from the aerosol measurements using several modelling approaches. The best-fit midvisible single-scatter albedos (approx. 0.89 to 0.93) obtained from the TARFOX flux comparisons are in accord with values derived by independent techniques. In ACE-2 we measured optical depth and extinction spectra for both European urban-marine aerosols and free-tropospheric African dust aerosols, using sunphotometers on the R/V Vodyanitskiy and the Pelican. Preliminary values for the radiative flux sensitivities (Delta Flux / Delta Optical depth) computed for ACE-2 aerosols (boundary layer and African dust) over ocean are similar to those found in TARFOX. Combining a satellite-derived optical depth climatology with the aerosol optical model validated for flux sensitivities in TARFOX provides first-cut estimates of aerosol-induced flux changes over the Atlantic Ocean.

  10. Campaign datasets for ARM Cloud Aerosol Precipitation Experiment (ACAPEX)

    SciTech Connect

    Leung, L. Ruby; Mei, Fan; Comstock, Jennifer; DeMott, Paul; Gero, Jonathan; Hubee, John; Matthews, Alyssa; Nalli, Nicholas; Pekour, Mikhail; Prather, Kimberly; Sedlackek, Arthur; Springston, Stephen; Tomlinson, Jason; Chand, Duli

    2015-08-12

    This campaign consisted of the deployment of the DOE ARM Mobile Facility 2 (AMF2) and the ARM Aerial Facility (AAF) G-1 in a field campaign called ARM Cloud Aerosol Precipitation Experiment (ACAPEX), which took place in conjunction with CalWater 2- a NOAA field campaign. The joint CalWater 2/ACAPEX field campaign aimed 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. The observational strategy consisted of the use of land and offshore assets to monitor: 1. the evolution and structure of ARs from near their regions of development 2. the long-range transport of aerosols in the eastern North Pacific and potential interactions with ARs 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  12. Spectral aerosol direct radiative forcing from airborne radiative measurements during CalNex and ARCTAS

    NASA Astrophysics Data System (ADS)

    Leblanc, Samuel E.; Schmidt, K. S.; Pilewskie, P.; Redemann, J.; Hostetler, C.; Ferrare, R.; Hair, J.; Langridge, J. M.; Lack, D. A.

    2012-09-01

    This study presents the aerosol radiative forcing derived from airborne measurements of shortwave spectral irradiance during the 2010 Research at the Nexus of Air Quality and Climate Change (CalNex). Relative forcing efficiency, the radiative forcing normalized by aerosol optical thickness and incident irradiance, is a means of comparing the aerosol radiative forcing for different conditions. In this study, it is used to put the aerosol radiative effects of an air mass in the Los Angeles basin in context with case studies from three field missions that targeted other regions and aerosol types, including a case study from the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS). For CalNex, we relied on irradiance measurements onboard the NOAA P-3 aircraft during a flight on 19 May 2010 over a ground station. CalNex presented a difficulty for determining forcing efficiency since one of the input parameters, optical thickness, was not available from the same aircraft. However, extinction profiles were available from a nearby aircraft. An existing retrieval algorithm was modified to use those measurements as initial estimate for the missing optical thickness. In addition, single scattering albedo and asymmetry parameter (secondary products of the method), were compared with CalNex in situ measurements. The CalNex relative forcing efficiency spectra agreed with earlier studies that found this parameter to be constrained at each wavelength within 20% per unit of aerosol optical thickness at 500 nm regardless of aerosol type and experiment, except for highly absorbing aerosols sampled near Mexico City. The diurnally averaged below-layer forcing efficiency integrated over the wavelength range of 350-700 nm for CalNex is estimated to be -58.6 ± 13.8 W/m2, whereas for the ARCTAS case it is -48.7 ± 11.5 W/m2.

  13. In Situ Measurements of Aerosol Mass Concentration and Spectral Absorption in Xianghe, SE of Beijing, China

    NASA Astrophysics Data System (ADS)

    Chaudhry, Z.; Martins, V.; Li, Z.

    2005-12-01

    China's rapid industrialization over the last few decades has affected air quality in many regions of China, and even the regional climate. As a part of the EAST-AIRE (East Asian Study of Tropospheric Aerosols: an International Regional Experiment) study, Nuclepore filters were collected in two size ranges (PM10 and PM2.5) at 12 hour intervals since January 2005 at Xianghe, about 70 km southeast of Beijing. Each filter was analyzed for mass concentration, aerosol scattering and absorption efficiencies. Mass concentrations during the winter months (January-March) ranged from 9 to 459 μg/m3 in the coarse mode with an average concentration of 122 μg/m3, and from 11 to 203 μg/m3 in the fine mode with an average concentration of 45 μg/m3. While some of the extreme values are likely linked to local emissions, regional air pollution episodes also played important roles. Absorption efficiency measurements at 550 nm show very high values compared to measurements performed in the United States during the CLAMS experiment. The spectral mass absorption efficiency was measured from 350 to 2500 nm and shows large differences between the absorption properties of soil dust, black carbon, and organic aerosols. The strong spectral differences observed can be related to differences in refractive indices from the several collected species and particle size effects. The absorption properties from aerosols measured in China show large absorption efficiencies, compared to aerosols measured in the US, possibly linked to different technology practices used in these countries. For organic plus black carbon aerosols, where the refractive index seems to be relatively constant, the absorption efficiency spectral dependence for fine mode aerosols falls between 1/λ and 1/λ2. The coarse mode absorption shows much less spectral dependence.

  14. Calculating Capstone depleted uranium aerosol concentrations from beta activity measurements.

    PubMed

    Szrom, Frances; Falo, Gerald A; Parkhurst, Mary Ann; Whicker, Jeffrey J; Alberth, David P

    2009-03-01

    Beta activity measurements were used as surrogate measurements of uranium mass in aerosol samples collected during the field testing phase of the Capstone Depleted Uranium (DU) Aerosol Study. These aerosol samples generated by the perforation of armored combat vehicles were used to characterize the DU source term for the subsequent Human Health Risk Assessment (HHRA) of Capstone aerosols. Establishing a calibration curve between beta activity measurements and uranium mass measurements is straightforward if the uranium isotopes are in equilibrium with their immediate short-lived, beta-emitting progeny. For DU samples collected during the Capstone study, it was determined that the equilibrium between the uranium isotopes and their immediate short-lived, beta-emitting progeny had been disrupted when penetrators had perforated target vehicles. Adjustments were made to account for the disrupted equilibrium and for wall losses in the aerosol samplers. Values for the equilibrium fraction ranged from 0.16 to 1, and the wall loss correction factors ranged from 1 to 1.92. This paper describes the process used and adjustments necessary to calculate uranium mass from proportional counting measurements.

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

    PubMed

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

    2013-07-01

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

  16. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Water Vapor in ACE-Asia and Their Comparisons to Correlative Measurements

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Redemann, J.; Livingston, J.; Russell, P.; Hegg, D.; Wang, J.; Kahn, R.; Hsu, C.; Masonis, S.; Murayama, T.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    In the Spring 2001 phase of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia), the 6-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) operated on 15 of the 19 research flights of the NCAR C-130, while its 14-channel counterpart (AATS-14) flew successfully on all 19 research flights of the CIRPAS Twin Otter. ACE-Asia studied aerosol outflow from the Asian continent to the Pacific basin. It was designed to integrate suborbital and satellite measurements and models to reduce the uncertainty in calculations of the climate forcing due to aerosols. AATS-6 and AATS-14 measured solar beam transmission at six and 14 wavelengths (380-1021 and 354-1558 nm, respectively), yielding aerosol optical depth (AOD) spectra and columnar water vapor (CWV). Vertical differentiation in profiles yielded aerosol extinction spectra and water vapor concentration. In this paper, we plan to present examples of the following, preliminary findings that are based in part on our airborne sunphotometer measurements: (1) The wavelength dependence of sunphotometer-derived AOD and extinction indicates that supermicron dust was often a major component of the aerosol, frequently extending to high altitudes. The percentage of full-column AOD (525 nm) that Jay above 3 km was typically 34+/-13%. In contrast, the analogous percentage of columnar water vapor was only 10+/-4%; (2) Initial comparison studies between AOD data obtained by AATS-6 and AATS-14 during coordinated low-level flight legs show agreement well within the instruments' error bars; (3) Aerosol extinction has been derived from airborne in situ measurements of scattering (nephelometers) and absorption (particle soot/ absorption photometer, PSAP) or calculated from particle size distribution measurements (mobility analyzers and aerodynamic particle sizers). Comparison with corresponding extinction values derived from the Ames airborne sunphotometer measurements shows good agreement for the vertical distribution

  17. Three optical methods for remotely measuring aerosol size distributions.

    NASA Technical Reports Server (NTRS)

    Reagan, J. A.; Herman, B. M.

    1971-01-01

    Three optical probing methods for remotely measuring atmospheric aerosol size distributions are discussed and contrasted. The particular detection methods which are considered make use of monostatic lidar (laser radar), bistatic lidar, and solar radiometer sensing techniques. The theory of each of these measurement techniques is discussed briefly, and the necessary constraints which must be applied to obtain aerosol size distribution information from such measurements are pointed out. Theoretical and/or experimental results are also presented which demonstrate the utility of the three proposed probing methods.

  18. 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.

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

    PubMed

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

    1995-03-01

    Comparative pyrolysis mass spectrometric data of Titan aerosol analogues, 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 interpretation of Titan atmosphere data from the Huygens probe in the future.

  20. Intercomparison of Remote and Flight Level Measured Aerosol Backscatter Coefficient During GLOBE 2 Pacific Survey Mission

    NASA Technical Reports Server (NTRS)

    Cutten, D. R.; Spinhime, J. D.; Menzies, R. T.; Bowdle, D. A.; Srivastava, V.; Pueschel, R. F.; Clarke, A. D.; Rothermel, J.

    1998-01-01

    Aerosol backscatter coefficient data are examined from two local flights undertaken during NASA's GLObal Backscatter Experiment (GLOBE) in May - June, 1990. During each of these two flights the aircraft traversed different altitudes within a region of the atmosphere defined by the same set of latitude and longitude coordinates. This provides an ideal opportunity to allow flight level measured or modeled aerosol backscafter to be compared with pulsed lidar aerosol backscafter data that were obtained at these same altitudes either earlier or later than the flight level measurements. Aerosol backscafter comparisons were made at 1.06-, 9.11- and 9.25-mm wavelengths, using data from three lidar systems and two aerosol optical counters. The best agreement between all sensor's was found in the altitude region below 7 km where backscafter values were moderately high at all three wavelengths. Above this altitude the pulsed lidar backscafter data at 1.06- and 9.25-mm wavelengths were higher than the flight level data obtained from the CW lidar or derived from the optical counters. Possible reasons are offered to explain this discrepancy. During the Japan local flight, microphysics analysis revealed: (1) evidence of a strong advected seasalt aerosol plume from the marine boundary layer, and (2) where backscatter was low, the large lidar sampling volume included many large particles which were of different chemical composition to the small particle category sampled by the particle counters.

  1. 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).

  2. RADIOCARBON MEASUREMENTS ON PM-2.5 AMBIENT AEROSOL

    EPA Science Inventory

    Radiocarbon (14C) measurements provide an estimate of the fraction of carbon in a sample that is biogenic. The methodology has been extensively used in past wintertime studies to quantify the contribution of wood smoke to ambient aerosol. In summertime such measurements can p...

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

    NASA Technical Reports Server (NTRS)

    Engle, C. D.

    1982-01-01

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

  4. A New Stratospheric Aerosol Product from CALIPSO Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Kar, J.; Vaughan, M.; Trepte, C. R.; Winker, D. M.; Vernier, J. P.; Pitts, M. C.; Young, S. A.; Liu, Z.; Lucker, P.; Tackett, J. L.; Omar, A. H.

    2014-12-01

    Stratospheric aerosols are derived from precursor SO2 and OCS gases transported from the lower troposphere. Volcanic injections can also enhance aerosol loadings far above background levels. The latter can exert a significant influence on the Earth's radiation budget for major and even minor eruptions. Careful measurements are needed, therefore, to monitor the distribution and evolution of stratospheric aerosols for climate related studies. The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission has been acquiring profile measurements of clouds and aerosols since 2006, leading to major advances in our understanding of tropospheric aerosol and cloud properties and the processes that control them. The CALIPSO products have also enabled new insights into polar stratospheric clouds and stratospheric aerosols. Vernier et al (2009,JGR,114,D00H10) reported on the construction of a modified CALIPSO lidar product that corrected minor artifacts with the original lidar calibration that affected stratospheric aerosol investigations. A significantly improved CALIPSO Lidar Version 4 Level 1 product has been recently released addressing these calibration issues and has resulted in enhanced signal levels and a highly stable record over the span of the mission. Based on this product, a new 3D gridded stratospheric CALIPSO data product is under development and being targeted for release in 2015. A key emphasis of this new product is to bridge the measurement gap between the SAGE II and SAGE III data record (1984-2005) and the start of measurements from the new SAGE III instrument to be deployed on the International Space Station in 2016. The primary parameters delivered in the CALIPSO stratospheric data products will be attenuated scattering ratio and aerosol extinction profiles, both averaged over one month intervals and binned into an equal angle grid of constant latitude and longitude with a vertical resolution of 900m. We will present the overall

  5. Size and concentration measurement of an industrial aerosol

    SciTech Connect

    O'Brien, D.; Baron, P.; Willeke, K.

    1986-07-01

    Several real-time particle sizing instruments were evaluated for measuring the size distribution and concentration of the aerosol produced during the high speed grinding of gray iron castings. Aerosol was sampled in the airstream entrained by the motion of a spinning grinding wheel in a pilot grinding operation. Measurement methods based on differing physical principles were selected for evaluation and compared: particle inertia (aerodynamic particle sizer and quartz crystal microbalance cascade impactor); light scattering (laser aerosol spectrometer); and projected-area microscopy (scanning electron microscope). Inferences of aerodynamic diameter based on measurements by the laser aerosol spectrometer consistently undersized that determined by the aerodynamic particle sizer by a factor of 1.5. Estimates of aerodynamic diameters from projected area diameters determined by scanning electron microscopy differed from those obtained by the aerodynamic particle sizer by a factor of 2. Differences appeared to be a non-linear function of particle diameter. Estimates of respirable mass determined from mass-weighted particle size spectra varied by a factor of 6 between the largest estimate (scanning electron microscope) and the smallest estimate (laser aerosol spectrometer).

  6. Size and concentration measurement of an industrial aerosol.

    PubMed

    O'Brien, D; Baron, P; Willeke, K

    1986-07-01

    Several real-time particle sizing instruments were evaluated for measuring the size distribution and concentration of the aerosol produced during the high speed grinding of gray iron castings. Aerosol was sampled in the airstream entrained by the motion of a spinning grinding wheel in a pilot grinding operation. Measurement methods based on differing physical principles were selected for evaluation and compared: particle inertia (aerodynamic particle sizer and quartz crystal microbalance cascade impactor); light scattering (laser aerosol spectrometer); and projected-area microscopy (scanning electron microscope). Inferences of aerodynamic diameter based on measurements by the laser aerosol spectrometer consistently undersized that determined by the aerodynamic particle sizer by a factor of 1.5. Estimates of aerodynamic diameters from projected area diameters determined by scanning electron microscopy differed from those obtained by the aerodynamic particle sizer by a factor of 2. Differences appeared to be a non-linear function of particle diameter. Estimates of respirable mass determined from mass-weighted particle size spectra varied by a factor of 6 between the largest estimate (scanning electron microscope) and the smallest estimate (laser aerosol spectrometer).

  7. Method of measuring charge distribution of nanosized aerosols.

    PubMed

    Kim, S H; Woo, K S; Liu, B Y H; Zachariah, M R

    2005-02-01

    In this paper, we present the development of a method to accurately measure the positive and negative charge distribution of nanosized aerosols using a tandem differential mobility analyzer (TDMA) system. From the series of TDMA measurements, the charge fraction of nanosized aerosol particles was obtained as a function of equivalent mobility particle diameter ranging from 50 to 200 nm. The capability of this new approach was implemented by sampling from a laminar diffusion flame which provides a source of highly charged particles due to naturally occurring flame ionization process. The results from the TDMA measurement provide the charge distribution of nanosized aerosols which we found to be in reasonable agreement with Boltzmann equilibrium charge distribution theory and a theory based upon charge population balance equation (PBE) combined with Fuchs theory (N.A. Fuchs, Geofis. Pura Appl. 56 (1963) 185). The theoretically estimated charge distribution of aerosol particles based on the PBE provides insight into the charging processes of nanosized aerosols surrounded by bipolar ions and electrons, and agree well with the TDMA results.

  8. Optical and physical properties of stratospheric aerosols from balloon measurements in the visible and near-infrared domains. III. Presence of aerosols in the middle stratosphere.

    PubMed

    Renard, Jean-Baptiste; Ovarlez, Joëlle; Berthet, Gwenaël; Fussen, Didier; Vanhellemont, Filip; Brogniez, Colette; Hadamcik, Edith; Chartier, Michel; Ovarlez, Henri

    2005-07-01

    The aerosol extinction measurements in the ultraviolet and visible wavelengths by the balloonborne spectrometer Spectroscopie d'Absorption Lunaire pour l'Observation des Minoritaires Ozone et NOx (SALOMON) show that aerosols are present in the middle stratosphere, above 25-km altitude. These observations are confirmed by the extinction measurements performed by a solar occultation radiometer. The balloonborne Laboratoire de Météorologie Dynamique (LMD) counter instrument also confirms the presence of aerosol around 30-km altitude, with an unrealistic excess of micronic particles assuming that only liquid sulfate aerosols are present. An unexpected spectral structure around 640-nm observed by SALOMON is also detectable in extinction measurements by the satellite instrument Stratospheric Aerosols and Gas Experiment III. This set of measurements could indicate that solid aerosols were detected at these altitude ranges. The amount of soot detected up to now in the lower stratosphere is too low to explain these measurements. Thus, the presence of interplanetary dust grains and micrometeorites may need to be invoked. Moreover, it seems that these grains fill the stratosphere in stratified layers.

  9. Optical and physical properties of stratospheric aerosols from balloon measurements in the visible and near-infrared domains. III. Presence of aerosols in the middle stratosphere

    NASA Astrophysics Data System (ADS)

    Renard, Jean-Baptiste; Ovarlez, Joëlle; Berthet, Gwenaël; Fussen, Didier; Vanhellemont, Filip; Brogniez, Colette; Hadamcik, Edith; Chartier, Michel; Ovarlez, Henri

    2005-07-01

    The aerosol extinction measurements in the ultraviolet and visible wavelengths by the balloonborne spectrometer Spectroscopie d'Absorption Lunaire pour l'Observation des Minoritaires Ozone et NO_x (SALOMON) show that aerosols are present in the middle stratosphere, above 25-km altitude. These observations are confirmed by the extinction measurements performed by a solar occultation radiometer. The balloonborne Laboratoire de Météorologie Dynamique (LMD) counter instrument also confirms the presence of aerosol around 30-km altitude, with an unrealistic excess of micronic particles assuming that only liquid sulfate aerosols are present. An unexpected spectral structure around 640-nm observed by SALOMON is also detectable in extinction measurements by the satellite instrument Stratospheric Aerosols and Gas Experiment III. This set of measurements could indicate that solid aerosols were detected at these altitude ranges. The amount of soot detected up to now in the lower stratosphere is too low to explain these measurements. Thus, the presence of interplanetary dust grains and micrometeorites may need to be invoked. Moreover, it seems that these grains fill the stratosphere in stratified layers.

  10. Accuracy of near-surface aerosol extinction determined from columnar aerosol optical depth measurements in Reno, NV, USA

    NASA Astrophysics Data System (ADS)

    Loría-Salazar, S. Marcela; Arnott, W. Patrick; Moosmüller, Hans

    2014-10-01

    The aim of the present work is a detailed analysis of aerosol columnar optical depth as a tool to determine near-surface aerosol extinction in Reno, Nevada, USA, during the summer of 2012. Ground and columnar aerosol optical properties were obtained by use of in situ Photoacoustic and Integrated Nephelometer and Cimel CE-318 Sun photometer instruments, respectively. Both techniques showed that seasonal weather changes and fire plumes had enormous influence on local aerosol optics. The apparent optical height followed the shape but not magnitude of the development of the convective boundary layer when fire conditions were not present. Back trajectory analysis demonstrated that a local flow known as the Washoe Zephyr circulation often induced aerosol transport from Northern California over the Sierra Nevada Mountains that increased the aerosol optical depth at 500 nm during afternoons when compared with mornings. Aerosol fine mode fraction indicated that afternoon aerosols in June and July and fire plumes in August were dominated by submicron particles, suggesting upwind urban plume biogenically enhanced evolution toward substantial secondary aerosol formation. This fine particle optical depth was inferred to be beyond the surface, thereby complicating use of remote sensing measurements for near-ground aerosol extinction measurements. It is likely that coarse mode depletes fine mode aerosol near the surface by coagulation and condensation of precursor gases.

  11. Photo-acoustic measurements of gas and aerosol absorption with diode lasers.

    PubMed

    Ponomarev, Yu N

    2004-12-01

    The results of designing multipurpose high-sensitive photo-acoustic (PA) detectors and their application to high-resolution diode laser spectroscopy of molecular gases, gas analysis, and aerosol absorption measurements are summarized in this paper. The hardware and software of the diode laser spectrometer with a Helmholtz resonant PA detector providing an absorption sensitivity limit of better than 10(-7)Wm(-1)Hz(-1/2) are described. A procedure is proposed for an experiment involving the measurements of the rotational structure of hot vibrational bands of molecules. The results of the application of the nonresonant PA cell with temporal resolution of signals to measurements of weak nonresonant absorption of gases and soot aerosols are presented, and the possibility of creating a broad-band PA laser diode aerosol-meter is discussed.

  12. Hygroscopic Measurements of Aerosol Particles in Colorado during the Discover AQ Campaign 2014

    NASA Astrophysics Data System (ADS)

    Orozco, D.; Delgado, R.; Espinosa, R.; Martins, J. V.; Hoff, R. M.

    2014-12-01

    In ambient conditions, aerosol particles experience hygroscopic growth due to the influence of relative humidity (RH), scattering more light than when the particles are dry. The quantitative knowledge of the RH effect and its influence on the light scattering and, in particular, on the phase function and polarization of aerosol particles is of substantial importance when comparing ground observations with other optical aerosol measurements such satellite and sunphotometric retrievals of aerosol optical depth and their inversions. In the summer of 2014, the DISCOVER-AQ campaign was held in Colorado, where systematic and concurrent observations of column- integrated surface, and vertically-resolved distributions of aerosols and trace gases relevant to air quality and their evolution during the day were observed. Aerosol optical properties were measured in the UMBC trailer at the city of Golden using a TSI-3563 nephelometer and an in-situ Polarized Imaging Nephelometer (PI-NEPH) designed and built by the LACO group at UMBC. The PI-NEPH measures aerosol phase matrix components in high angular range between 2 and 178 degrees scattering angle at three wavelengths (λ=473, 532 and 671nm). The two measured elements of the phase matrix, intensity (P11) and linear polarization (P12) provide extensive characterization of the scattering properties of the studied aerosol. The scattering coefficient, P11 and P12 were measured under different humidity conditions to obtain the enhancement factor f(RH) and the dependence of P11 and P12 to RH using a humidifier dryer system covering a RH range from 20 to 90%. The ratio between scattering coefficients at high and low humidity in Golden Colorado showed relatively low hygroscopic growth in the aerosol particles f(RH=80%) was 1.27±0.19 for the first three weeks of sampling. According to speciated measurements performed at the UMBC trailer, the predominance of dust and organic aerosols over more hygroscopic nitrate and sulfate in the

  13. On the Tropospheric Measurements of Ozone by the Stratospheric Aerosol and Gas Experiment II (SAGE II, version 6.1) in the Tropics

    NASA Technical Reports Server (NTRS)

    Kar, J.; Trepte, C. R.; Thomason, L. W.; Zawodny, J. M.; Cunnold, D. M.; Wang, H. J.

    2002-01-01

    Tropospheric measurements of ozone from SAGE II (version 6.1) in the tropics have been analyzed using 12 years of data (1985-1990, 1994-1999). The seasonally averaged vertical profiles of the ozone mixing ratio in the upper troposphere have been presented for the first time from satellite measurements. These profiles show qualitative similarities with corresponding seasonal mean ozonesonde profiles at northern and southern tropical stations and are about 40-50% less than the sonde values. Despite this systematic offset, the measurements appear to be consistent with a zonal wave one pattern in the upper tropospheric column ozone and with the recently predicted summertime ozone enhancement over the Middle East. These results thus affirm the usefulness of the occultation method in studying tropospheric ozone.

  14. Vertical Profiles of Cloud Condensation Nuclei, Condensation Nuclei, Optical Aerosol, Aerosol Optical Properties, and Aerosol Volatility Measured from Balloons

    NASA Technical Reports Server (NTRS)

    Deshler, T.; Snider, J. R.; Vali, G.

    1998-01-01

    Under the support of this grant a balloon-borne gondola containing a variety of aerosol instruments was developed and flown from Laramie, Wyoming, (41 deg N, 105 deg W) and from Lauder, New Zealand (45 deg S, 170 deg E). The gondola includes instruments to measure the concentrations of condensation nuclei (CN), cloud condensation nuclei (CCN), optically detectable aerosol (OA.) (r greater than or equal to 0.15 - 2.0 microns), and optical scattering properties using a nephelometer (lambda = 530 microns). All instruments sampled from a common inlet which was heated to 40 C on ascent and to 160 C on descent. Flights with the CN counter, OA counter, and nephelometer began in July 1994. The CCN counter was added in November 1994, and the engineering problems were solved by June 1995. Since then the flights have included all four instruments, and were completed in January 1998. Altogether there were 20 flights from Laramie, approximately 5 per year, and 2 from Lauder. Of these there were one or more engineering problems on 6 of the flights from Laramie, hence the data are somewhat limited on those 6 flights, while a complete data set was obtained from the other 14 flights. Good CCN data are available from 12 of the Laramie flights. The two flights from Lauder in January 1998 were successful for all measurements. The results from these flights, and the development of the balloon-bome CCN counter have formed the basis for five conference presentations. The heated and unheated CN and OA measurements have been used to estimate the mass fraction of the aerosol volatile, while comparisons of the nephelometer measurements were used to estimate the light scattering, associated with the volatile aerosol. These estimates were calculated for 0.5 km averages of the ascent and descent data between 2.5 km and the tropopause, near 11.5 km.

  15. Measuring the influence of aerosols and albedo on sky polarization.

    PubMed

    Kreuter, A; Emde, C; Blumthaler, M

    2010-11-01

    All-sky distributions of the polarized radiance are measured using an automated fish-eye camera system with a rotating polarizer. For a large range of aerosol and surface albedo situations, the influence on the degree of polarization and sky radiance is investigated. The range of aerosol optical depth and albedo is 0.05-0.5 and 0.1-0.75, respectively. For this range of parameters, a reduction of the degree of polarization from about 0.7 to 0.4 was observed. The analysis is done for 90° scattering angle in the principal plane under clear sky conditions for a broadband channel of 450 ± 25 nm and solar zenith angles between 55° and 60°. Radiative transfer calculations considering three different aerosol mixtures are performed and and agree with the measurements within the statistical error.

  16. Development of a continuous aerosol mass concentration measurement device.

    PubMed

    Bémer, D; Thomas, D; Contal, P; Subra, I

    2003-08-01

    A dynamic aerosol mass concentration measurement device has been developed for personal sampling. Its principle consists in sampling the aerosol on a filter and monitoring the change of pressure drop over time (Delta P). Ensuring that the linearity of the Delta P = f(mass of particles per unit area of filter) relationship has been well established, the change of concentration can be deduced. The response of the system was validated in the laboratory with a 3.5 microm alumina aerosol (mass median diameter) generated inside a 1-m(3) ventilated enclosure. As the theory predicted that the mass sensitivity of the system would vary inversely with the square of the particle diameter, only sufficiently fine aerosols were able to be measured. The system was tested in the field in a mechanical workshop in the vicinity of an arc-welding station. The aerosol produced by welding is indeed particularly well-adapted due to the sub-micronic size of the particles. The device developed, despite this limitation, has numerous advantages over other techniques: robustness, compactness, reliability of calibration, and ease of use.

  17. Measurements of the absorption coefficient of stratospheric aerosols

    NASA Technical Reports Server (NTRS)

    Ogren, J. A.; Ahlquist, N. C.; Clarke, A. D.; Charlson, R. J.

    1981-01-01

    The absorption coefficients of stratospheric aerosols are measured using a variation on the integrating plate method. The technique is based on the decrease in the transparency of a substrate when an absorbing aerosol is deposited on it. A Lambert scatterer is placed behind the substrate to integrate forward scattered light and minimize the effect of scattering on the measurement. The low pressure in the stratosphere is used for the direct impaction of particles onto a narrow strip of opal glass. The eight samples collected had a median value of 4 x 10 to the -9th m with an uncertainty of + or - 5 x 10 to the -9th m. If this absorption is due to graphitic carbon, then its concentration is estimated at about 0.4 ng/cu m, or about 0.25% of the total aerosol mass concentration. Estimates of the aerosol scattering coefficients based on satellite extinction inversions result in an aerosol single-scattering albedo in the range of 0.96-1.0.

  18. Ship-based Aerosol Optical Depth Measurements Near Antarctica

    NASA Astrophysics Data System (ADS)

    Sakerin, S. M.; Smirnov, A.; Kabanov, D. M.; Turchinovich, Y. S.; Holben, B. N.; Radionov, V. F.; Slutsker, I.

    2006-12-01

    Aerosol optical properties over the oceans were studied in November 2005 January 2006 onboard the R/V Akademik Fedorov within the framework of the 51st Russian Antarctic Expedition. Measurements were made with the handheld sunphotometer Microtops II. The sunphotometer was calibrated against the AERONET reference CIMEL radiometer. The direct sun measurements were acquired in five spectral channels at 340, 440, 675, 870 and 936 nm. Aerosol optical depth was retrieved by applying the AERONET processing algorithm (Version 2). The paper presents results of measurements along the Atlantic transect and in the Antarctic region, where the main data volume was obtained (spanning 20 days). During the measurement period near Antarctica aerosol optical depth was low (daily averages varied within 0.02-0.04 at a wavelength 440 nm). Average spectral dependence of aerosol optical depth showed usual monotonic behavior, decreasing from 0.037 at 440 nm to 0.022 at 870 nm. Daily averaged Angstrom parameter was 0.84. Spatial and temporal variations in the Antarctic region were less or about 0.02 which is comparable with the measurement uncertainty. For a few days Microtops was collocated with the stationary sunphotometer ABAS-3 from the coastal Antarctic station Myrnyi and took simultaneous measurements. Presented results are compared with the long-term observations in Antarctica.

  19. One year of urban background fluorescent aerosol measurements

    NASA Astrophysics Data System (ADS)

    Pope, Francis

    2016-04-01

    Online aerosol fluorescence is a popular methodology for detecting bioaerosols in the atmosphere. In recent years there has been considerable effort into refining the technique to be able to distinguish between different bioaerosol classes such as pollen, spores and bacteria. A near continuous record of aerosol fluorescence measurements has been recorded at an urban background observation site in Birmingham, UK for the year 2015. Fluorescence measurements were performed using the Biral aerosol fluorescence spectrometer (AFS) which measures both UV and visible fluorescence resulting from the excitation of aerosol particles at 280 nm. Speciation of the fluorescent particles into different bioaerosol class is possible with the AFS but the lack of particle sizing makes the task difficult compared to other techniques. In addition to the fluorescence measurements, further campaign mode measurements were also generated for size segregated total particle numbers, ozone, nitrogen oxides and other chemical species. These measurements allow for the influence of road traffic on the concentration of fluorescent particle to be determined. This presentation will provide an in depth look into how bioaerosol concentrations and speciation (pollen, spores and bacteria) change throughout the year. These changes will be linked to local and regional meteorology and climate. In particular, the consequences of the unusually warm UK winter upon bioaerosol concentrations will be highlighted.

  20. ACE-Asia Aerosol Optical Depth and Water Vapor Measured by Airborne Sunphotometers and Related to Other Measurements and Calculations

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Russell, P. B.; Schmid, B.; Redemann, J.; Eilers, J. A.; Ramirez, S. A.; Kahn, R.; Hegg, D.; Pilewskie, P.; Anderson, T.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    In the Spring 2001 phase of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia), the 6-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) operated on 15 of the 19 research flights of the NCAR C-130, while its 14-channel counterpart (AATS- 14) flew successfully on all 18 research flights of the CIRPAS Twin Otter. ACE-Asia studied aerosol outflow from the Asian continent to the Pacific basin. It was designed to integrate suborbital and satellite measurements and models so as to reduce the uncertainty in calculations of the climate forcing due to aerosols. AATS-6 and AATS-14 measured solar beam transmission at 6 and 14 wavelengths (380-1021 and 354-1558 nm, respectively), yielding aerosol optical depth (AOD) spectra and column water vapor (CWV). Vertical differentiation in profiles yielded aerosol extinction spectra and water vapor concentration. The wavelength dependence of these AOD and extinction spectra indicates that supermicron dust was often a major component of the ACE-Asia aerosol. Frequently this dust-containing aerosol extended to high altitudes. For example, in AATS- 14 profiles analyzed to date, 36% of full-column AOD at 525 nm was above 3 km. In contrast, only 10% of CWV was above 3 km. Analyses and applications of AATS-6 and AATS-14 data to date include comparisons to (i) extinction products derived using in situ measurements, (ii) extinction profiles derived from lidar measurements, and (iii) AOD retrievals from the Multi-angle Imaging Spectro-Radiometer (MISR) aboard the TERRA satellite. Other planned collaborative studies include comparisons to results from size spectrometers, chemical measurements, other satellite sensors, flux radiometers, and chemical transport models. Early results of these studies will be presented.

  1. Continuous measurements of aerosol particles in Arctic Russia and Finland

    NASA Astrophysics Data System (ADS)

    Asmi, Eija; Kondratyev, Vladimir; Brus, David; Lihavainen, Heikki; Laurila, Tuomas; Aurela, Mika; Hatakka, Juha; Viisanen, Yrjö; Reshetnikov, Alexander; Ivakhov, Victor; Uttal, Taneil; Makshtas, Alexander

    2013-04-01

    The Arctic and northern boreal regions of Eurasia are experiencing rapid environmental changes due to pressures by human activities. The largest anthropogenic climate forcings are due to aerosol particles and greenhouse gases (GHGs). The Arctic environment is highly sensitive to changes in aerosol concentrations or composition, largely due to the high surface reflectance for the most part of the year. Concentrations of aerosols in winter and spring Arctic are affected by 'Arctic Haze', a phenomenon suggested to arise from the transport of pollutants from lower latitudes and further strengthened by the strong stratification of the Arctic wintertime atmosphere. Sources and transport patterns of aerosols into the Arctic are, however, not fully understood. In order to monitor the changes within the Arctic region, as well as to understand the sources and feedback mechanisms, direct measurements of aerosols within the Arctic are needed. So far, direct year-round observations have been inadequate especially within the Russian side of the Arctic. This is the reason why a new climate observatory was founded in Tiksi, Russia. Tiksi meteorological observatory in northern Siberia (71o 36' N; 128o 53' E) on the shore of the Laptev Sea has been operating since 1930s. Recently, it was upgraded and joint in the network of the IASOA, in the framework of the International Polar Year Activity project. The project is run in collaboration between National Oceanic and Atmospheric Administration (NOAA) with the support of the National Science Foundation (NSF), Roshydromet (AARI and MGO units), government of the Republic of Sakha (Yakutia) and the Finnish Meteorological Institute (FMI). The research activities of FMI in Tiksi include e.g. continuous long-term measurements of aerosol physical properties, which have been successfully continued since summer 2010. These, together with the FMI measurements in Pallas station in northern Finland since 1999, provide important information on the

  2. Direct Aerosol Radiative Forcing: Calculations and Measurements from the Tropospheric

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Hignett, P.; Stowe, L. L.; Livingston, J. M.; Kinne, S.; Wong, J.; Chan, K. Roland (Technical Monitor)

    1997-01-01

    Radiative forcing is defined as the change in the net (downwelling minus upwelling) radiative flux at a given level in the atmosphere. This net flux is the radiative power density available to drive climatic processes in the earth-atmosphere system below that level. Recent research shows that radiative forcing by aerosol particles is a major source of uncertainty in climate predictions. To reduce those uncertainties, TARFOX was designed to determine direct (cloud-free) radiative forcing by the aerosols in one of the world's major industrial pollution plumes--that flowing from the east coast of the US over the Atlantic Ocean. TARFOX measured a variety of aerosol radiative effects (including direct forcing) while simultaneously measuring the chemical, physical, and optical properties of the aerosol particles causing those effects. The resulting data sets permit a wide variety of tests of the consistency, or closure, among the measurements and the models that link them. Because climate predictions use the same or similar model components, closure tests help to assess and reduce prediction uncertainties. In this work we use the TARFOX-determined aerosol, gas, and surface properties to compute radiative forcing for a variety of aerosol episodes, with inadvisable optical depths ranging from 0.07 to 0.6. We calculate forcing by several techniques with varying degrees of sophistication, in part to test the range of applicability of simplified techniques--which are often the only ones feasible in climate predictions by general circulation models (GCMs). We then compare computed forcing to that determined from: (1) Upwelling and downwelling fluxes (0.3-0.7 mm and 0.7-3.0 mm) measured by radiometers on the UK MRF C-130. and (2) Daily average cloud-free absorbed solar and emitted thermal radiative flux at the top of the atmosphere derived from the AVHRR radiometer on the NOAA- 14 satellite. The calculations and measurements all yield aerosol direct radiative forcing in the

  3. Aerosol mass spectrometry: particle-vaporizer interactions and their consequences for the measurements

    NASA Astrophysics Data System (ADS)

    Drewnick, F.; Diesch, J.-M.; Faber, P.; Borrmann, S.

    2015-09-01

    The Aerodyne aerosol mass spectrometer (AMS) is a frequently used instrument for on-line measurement of the ambient sub-micron aerosol composition. With the help of calibrations and a number of assumptions on the flash vaporization and electron impact ionization processes, this instrument provides robust quantitative information on various non-refractory ambient aerosol components. However, when measuring close to certain anthropogenic or marine sources of semi-refractory aerosols, several of these assumptions may not be met and measurement results might easily be incorrectly interpreted if not carefully analyzed for unique ions, isotope patterns, and potential slow vaporization associated with semi-refractory species. Here we discuss various aspects of the interaction of aerosol particles with the AMS tungsten vaporizer and the consequences for the measurement results: semi-refractory components - i.e., components that vaporize but do not flash-vaporize at the vaporizer and ionizer temperatures, like metal halides (e.g., chlorides, bromides or iodides of Al, Ba, Cd, Cu, Fe, Hg, K, Na, Pb, Sr, Zn) - can be measured semi-quantitatively despite their relatively slow vaporization from the vaporizer. Even though non-refractory components (e.g., NH4NO3 or (NH4)2SO4) vaporize quickly, under certain conditions their differences in vaporization kinetics can result in undesired biases in ion collection efficiency in thresholded measurements. Chemical reactions with oxygen from the aerosol flow can have an influence on the mass spectra for certain components (e.g., organic species). Finally, chemical reactions of the aerosol with the vaporizer surface can result in additional signals in the mass spectra (e.g., WO2Cl2-related signals from particulate Cl) and in conditioning or contamination of the vaporizer, with potential memory effects influencing the mass spectra of subsequent measurements. Laboratory experiments that investigate these particle-vaporizer interactions are

  4. Shortwave Radiative Fluxes, Solar-Beam Transmissions, and Aerosol Properties: TARFOX and ACE-2 Find More Absorption from Flux Radiometry than from Other Measurements

    NASA Technical Reports Server (NTRS)

    Russell, Philip B.; Redemann, J.; Schmid, B.; Livingston, J. M.; Bergstrom, R. W.; Ramirez, S. A.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    The Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) and the Second Aerosol Characterization Experiment (ACE-2) made simultaneous measurements of shortwave radiative fluxes, solar-beam transmissions, and the aerosols affecting those fluxes and transmissions. Besides the measured fluxes and transmissions, other obtained properties include aerosol scattering and absorption measured in situ at the surface and aloft; aerosol single scattering albedo retrieved from skylight radiances; and aerosol complex refractive index derived by combining profiles of backscatter, extinction, and size distribution. These measurements of North Atlantic boundary layer aerosols impacted by anthropogenic pollution revealed the following characteristic results: (1) Better agreement among different types of remote measurements of aerosols (e.g., optical depth, extinction, and backscattering from sunphotometers, satellites, and lidars) than between remote and in situ measurements; 2) More extinction derived from transmission measurements than from in situ measurements; (3) Larger aerosol absorption inferred from flux radiometry than from other measurements. When the measured relationships between downwelling flux and optical depth (or beam transmission) are used to derive best-fit single scattering albedos for the polluted boundary layer aerosol, both TARFOX and ACE-2 yield midvisible values of 0.90 +/- 0.04. The other techniques give larger single scattering albedos (i.e. less absorption) for the polluted boundary layer, with a typical result of 0.95 +/- 0.04. Although the flux-based results have the virtue of describing the column aerosol unperturbed by sampling, they are subject to questions about representativeness and other uncertainties (e.g., unknown gas absorption). Current uncertainties in aerosol single scattering albedo are large in terms of climate effects. They also have an important influence on aerosol optical depths retrieved from satellite radiances

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  6. Aerosol Optical Depth Measurements by Airborne Sun Photometer in SOLVE II: Comparisons to SAGE III, POAM III and Airborne Spectrometer Measurements

    NASA Technical Reports Server (NTRS)

    Russell, P.; Livingston, J.; Schmid, B.; Eilers, J.; Kolyer, R.; Redemann, J.; Ramirez, S.; Yee, J-H.; Swartz, W.; Shetter, R.

    2004-01-01

    The 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) measured solar-beam transmission on the NASA DC-8 during the Second SAGE III Ozone Loss and Validation Experiment (SOLVE II). This paper presents AATS-14 results for multiwavelength aerosol optical depth (AOD), including its spatial structure and comparisons to results from two satellite sensors and another DC-8 instrument. These are the Stratospheric Aerosol and Gas Experiment III (SAGE III), the Polar Ozone and Aerosol Measurement III (POAM III) and the Direct beam Irradiance Airborne Spectrometer (DIAS).

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    PubMed

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

    2015-06-01

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

  9. Aerosols

    Atmospheric Science Data Center

    2013-04-17

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

  10. A Micro Aerosol Sensor for the Measurement of Airborne Ultrafine Particles

    PubMed Central

    Zhang, Chao; Zhu, Rong; Yang, Wenming

    2016-01-01

    Particle number concentration and particle size are the two key parameters used to characterize exposure to airborne nanoparticles or ultrafine particles that have attracted the most attention. This paper proposes a simple micro aerosol sensor for detecting the number concentration and particle size of ultrafine particles with diameters from 50 to 253 nm based on electrical diffusion charging. The sensor is composed of a micro channel and a couple of planar electrodes printed on two circuit boards assembled in parallel, which thus integrate charging, precipitating and measurement elements into one chip, the overall size of which is 98 × 38 × 25 mm3. The experiment results demonstrate that the sensor is useful for measuring monodisperse aerosol particles with number concentrations from 300 to 2.5 × 104 /cm3 and particle sizes from 50 to 253 nm. The aerosol sensor has a simple structure and small size, which is favorable for use in handheld devices. PMID:26999156

  11. A Strategy to Assess Aerosol Direct Radiative Forcing of Climate Using Satellite Radiation Measurements

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    Atmospheric aerosols have a complex internal chemical composition and optical properties. Therefore it is difficult to model their impact on redistribution and absorption of solar radiation, and the consequent impact on atmospheric dynamics and climate. The use in climate models of isolated aerosol parameters retrieved from satellite data (e.g. optical thickness) may result in inconsistent calculations, if the model assumptions differ from these of the satellite retrieval schemes. Here we suggest a strategy to assess the direct impact of aerosol on the radiation budget at the top and bottom of the atmosphere using satellite and ground based measurements of the spectral solar radiation scattered by the aerosol. This method ensures consistent use of the satellite data and increases its accuracy. For Kaufman and Tanre: Strategy for aerosol direct forcing anthropogenic aerosol in the fine mode (e.g. biomass burning smoke and urban pollution) consistent use of satellite derived optical thickness can yield the aerosol impact on the spectral solar flux with accuracy an order of magnitude better than the optical thickness itself. For example, a simulated monthly average smoke optical thickness of 0.5 at 0.55 microns (forcing of 40-50 W/sq m) derived with an error of 20%, while the forcing can be measured directly with an error of only 0-2 W/sq m. Another example, the effect of large dust particles on reflection of solar flux can be derived three times better than retrievals of optical thickness. Since aerosol impacts not only the top of the atmosphere but also the surface irradiation, a combination of satellite and ground based measurements of the spectral flux, can be the most direct mechanism to evaluate the aerosol effect on climate and assimilate it in climate models. The strategy is applied to measurements from SCAR-B and the Tarfox experiments. In SCAR-B aircraft spectral data are used to derive the 24 hour radiative forcing of smoke at the top of the atmosphere of

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  13. Two-Column Aerosol Project: Aerosol Light Extinction Measurements Field Campaign Report

    SciTech Connect

    Dubey, Manvendra; Aiken, Allison; Berg, Larry K.; Freedman, Andrew; Gorkowski, Kyle

    2016-09-01

    We deployed Aerodyne Research Inc.’s first Cavity Attenuated Phase Shift extinction (CAPS PMex) monitor (built by Aerodyne) that measures light extinction by using a visible-light-emitting diode (LED) as a light source, a sample cell incorporating two high-reflectivity mirrors centered at the wavelength of the LED, and a vacuum photodiode detector in Cape Cod in 2012/13 for the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Two-Column Aerosol Project (TCAP). The efficacy of this instrument is based on the fact that aerosols are broadband scatterers and absorbers of light. The input LED is square-wave modulated and passed through the sample cell that distorts it due to exponential decay by aerosol light absorption and scattering; this is measured at the detector. The amount of phase shift of the light at the detector is used to determine the light extinction. This extinction measurement provides an absolute value, requiring no calibration. The goal was to compare the CAPS performance with direct measurements of absorption with ARM’s baseline photoacoustic soot spectrometer (PASS-3) and nephelometer instruments to evaluate its performance.

  14. Measurements of Gases and Aerosols during 2010Cal-Mex

    NASA Astrophysics Data System (ADS)

    Zheng, J.; Zhang, R.; Molina, L.

    2012-04-01

    The major goal of the collaborative Cal-Mex 2010 research project is to assess the sources and processing of emissions along the California-Mexico border region and their effects on regional air quality and climate in order to provide scientific information to decision makers of both nations when addressing these two inter-related issues. During the Cal-Mex 2010 field study, the TAMU teams have collected extensive data sets from Tijuana/San Diego border, including volatile organic compounds (VOCs), gaseous sulfuric acid (H2SO4) and a suite set of physical and chemical parameters of aerosols. This comprehensive data set requires additional effort to process and analyze the measurements of gases and aerosols during Cal-Mex 2010. In this talk, preliminary data analysis of gases and aerosols will be presented, including VOCs and particle mixing states, morphology, and effective densities.

  15. Measurement of mass distribution of chemical species in aerosol particles

    NASA Technical Reports Server (NTRS)

    Sinha, M. P.; Friedlander, S. K.

    1984-01-01

    Aerosols may be generated through the nebulizing of solutions and the evaporation of their solvent, leaving the dry solute particles. Attention is presently given to a method for the direct determination of the masses of chemical species in individual aerosol particles on a continuous, real-time basis, using mass spectrometry. After the aerosol particles are introduced into the ion source of a quadrupole mass spectrometer, the particles impinge on a hot rhenium filament in the mass spectrometer's ion source. The resulting vapor plume is ionized by electron bombardment, and a pulse of ions is generated by each particle. The intensities of different masses in the ion pulses can then be measured by the mass spectrometer.

  16. Aerosol measurements and validation of satellite-derived aerosol optical depth over the Kavaratti Cal-Val site

    NASA Astrophysics Data System (ADS)

    Babu, K. N.; Suthar, N. M.; Patel, P. N.; Mathur, A. K.

    2016-05-01

    Aerosols are short-lived with a residual time of about a week in the lower atmosphere and are concentrated around the source of origin. Aerosols are produced by variety of natural processes as well as by anthropogenic activities; it gets distributed in the atmosphere through turbulent mixing as well as transported away from the source of origin and thus results in its large seasonal and spatial variability. In this study, the CIMEL sun-photometer measurements at Kavaratti calibration and validation site are used to characterize the aerosols' nature at the measurement site. Also, these in-situ measurements are used to validate the satellite sensor derived aerosol optical depth (AOD) parameter. The data analysis shows that the locally generated aerosols are mostly of marine aerosols and other natural aerosols are transported desert dust. The anthropogenic aerosols are transported from mainland and they are found during the pre-monsoon season. Also aerosol measurements for five years (2009 - 2015) are being planned for validating the satellite sensors derived AOD products namely: OceanSat2-OCM2, MODIS-Terra and MODIS-Aqua.

  17. Coherent uncertainty analysis of aerosol measurements from multiple satellite sensors

    NASA Astrophysics Data System (ADS)

    Petrenko, M.; Ichoku, C.

    2013-02-01

    Aerosol retrievals from multiple spaceborne sensors, including MODIS (on Terra and Aqua), MISR, OMI, POLDER, CALIOP, and SeaWiFS - altogether, a total of 11 different aerosol products - were comparatively analyzed using data collocated with ground-based aerosol observations from the Aerosol Robotic Network (AERONET) stations within the Multi-sensor Aerosol Products Sampling System (MAPSS, http://giovanni.gsfc.nasa.gov/mapss/ and http://giovanni.gsfc.nasa.gov/aerostat/). The analysis was performed by comparing quality-screened satellite aerosol optical depth or thickness (AOD or AOT) retrievals during 2006-2010 to available collocated AERONET measurements globally, regionally, and seasonally, and deriving a number of statistical measures of accuracy. We used a robust statistical approach to detect and remove possible outliers in the collocated data that can bias the results of the analysis. Overall, the proportion of outliers in each of the quality-screened AOD products was within 12%. Squared correlation coefficient (R2) values of the satellite AOD retrievals relative to AERONET exceeded 0.6, with R2 for most of the products exceeding 0.7 over land and 0.8 over ocean. Root mean square error (RMSE) values for most of the AOD products were within 0.15 over land and 0.09 over ocean. We have been able to generate global maps showing regions where the different products present advantages over the others, as well as the relative performance of each product over different landcover types. It was observed that while MODIS, MISR, and SeaWiFS provide accurate retrievals over most of the landcover types, multi-angle capabilities make MISR the only sensor to retrieve reliable AOD over barren and snow/ice surfaces. Likewise, active sensing enables CALIOP to retrieve aerosol properties over bright-surface shrublands more accurately than the

  18. Coherent uncertainty analysis of aerosol measurements from multiple satellite sensors

    NASA Astrophysics Data System (ADS)

    Petrenko, M.; Ichoku, C.

    2013-07-01

    Aerosol retrievals from multiple spaceborne sensors, including MODIS (on Terra and Aqua), MISR, OMI, POLDER, CALIOP, and SeaWiFS - altogether, a total of 11 different aerosol products - were comparatively analyzed using data collocated with ground-based aerosol observations from the Aerosol Robotic Network (AERONET) stations within the Multi-sensor Aerosol Products Sampling System (MAPSS, http://giovanni.gsfc.nasa.gov/mapss/ and http://giovanni.gsfc.nasa.gov/aerostat/. The analysis was performed by comparing quality-screened satellite aerosol optical depth or thickness (AOD or AOT) retrievals during 2006-2010 to available collocated AERONET measurements globally, regionally, and seasonally, and deriving a number of statistical measures of accuracy. We used a robust statistical approach to detect and remove possible outliers in the collocated data that can bias the results of the analysis. Overall, the proportion of outliers in each of the quality-screened AOD products was within 7%. Squared correlation coefficient (R2) values of the satellite AOD retrievals relative to AERONET exceeded 0.8 for many of the analyzed products, while root mean square error (RMSE) values for most of the AOD products were within 0.15 over land and 0.07 over ocean. We have been able to generate global maps showing regions where the different products present advantages over the others, as well as the relative performance of each product over different land cover types. It was observed that while MODIS, MISR, and SeaWiFS provide accurate retrievals over most of the land cover types, multi-angle capabilities make MISR the only sensor to retrieve reliable AOD over barren and snow/ice surfaces. Likewise, active sensing enables CALIOP to retrieve aerosol properties over bright-surface closed shrublands more accurately than the other sensors, while POLDER, which

  19. Coherent Uncertainty Analysis of Aerosol Measurements from Multiple Satellite Sensors

    NASA Technical Reports Server (NTRS)

    Petrenko, M.; Ichoku, C.

    2013-01-01

    Aerosol retrievals from multiple spaceborne sensors, including MODIS (on Terra and Aqua), MISR, OMI, POLDER, CALIOP, and SeaWiFS altogether, a total of 11 different aerosol products were comparatively analyzed using data collocated with ground-based aerosol observations from the Aerosol Robotic Network (AERONET) stations within the Multi-sensor Aerosol Products Sampling System (MAPSS, http://giovanni.gsfc.nasa.gov/mapss/ and http://giovanni.gsfc.nasa.gov/aerostat/). The analysis was performed by comparing quality-screened satellite aerosol optical depth or thickness (AOD or AOT) retrievals during 2006-2010 to available collocated AERONET measurements globally, regionally, and seasonally, and deriving a number of statistical measures of accuracy. We used a robust statistical approach to detect and remove possible outliers in the collocated data that can bias the results of the analysis. Overall, the proportion of outliers in each of the quality-screened AOD products was within 12%. Squared correlation coefficient (R2) values of the satellite AOD retrievals relative to AERONET exceeded 0.6, with R2 for most of the products exceeding 0.7 over land and 0.8 over ocean. Root mean square error (RMSE) values for most of the AOD products were within 0.15 over land and 0.09 over ocean. We have been able to generate global maps showing regions where the different products present advantages over the others, as well as the relative performance of each product over different landcover types. It was observed that while MODIS, MISR, and SeaWiFS provide accurate retrievals over most of the landcover types, multi-angle capabilities make MISR the only sensor to retrieve reliable AOD over barren and snow / ice surfaces. Likewise, active sensing enables CALIOP to retrieve aerosol properties over bright-surface shrublands more accurately than the other sensors, while POLDER, which is the only one of the sensors capable of measuring polarized aerosols, outperforms other sensors in

  20. Evaluation of SAGE II and Balloon-Borne Stratospheric Aerosol Measurements

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Under funding from this proposal we evaluated measurements of stratospheric sulfate aerosols from three platforms. Two were satellite platforms providing solar extinction measurements, the Stratospheric Aerosol and Gas Experiment (SAGE) II using wavelengths from 0.386 - 1.02 microns, and the Halogen Occultation Experiment (HALOE) using wavelengths from 2.45 to 5.26 microns. The third set of measurements was from in situ sampling by balloonborne optical particle counters (OPCs). The goal was to determine the consistency among these data sets. This was accomplished through analysis of the existing measurement records, and through additional balloonborne OPC flights coinciding with new SAGE II observations over Laramie, Wyoming. All analyses used the SAGE II v 6.0 data. This project supported two balloon flights per year over Laramie dedicated to SAGE II coincidence. Because logistical factors, such as poor surface weather or unfavorable payload impact location, can make it difficult to routinely obtain close coincidences with SAGE II, we attempt to conduct nearly every Laramie flight (roughly one per month) in conjunction with a SAGE II overpass. The Laramie flight frequency has varied over the years depending on field commitments and funding sources. Current support for the Laramie measurements is from the National Science Foundation in addition to support from this NASA grant. We have also completed a variety of comparisons using aerosol measurements from SAGE II, OPCs, and HALOE. The instruments were compared for their various estimates of aerosol extinction at the SAGE II wavelengths and for aerosol surface area. Additional results, such as illustrated here, can be found in a recently accepted manuscript describing comparisons between SAGE II, HALOE, and OPCs for the period 1982 - 2000. While overall, the impression from these results is encouraging, the agreement of the measurements changes with latitude, altitude, time, and parameter. In the broadest sense

  1. Measurement of mixed biomass burning and mineral dust aerosol in the thermal infrared

    NASA Astrophysics Data System (ADS)

    Koehler, C. H.; Trautmann, T.; Lindermeir, E.

    2009-03-01

    From January 19th to February 7th, 2008, we installed a Fourier transform infrared spectrometer (FTIR) at Praia Airport on the island of Santiago, Cape Verde. Our goal was to measure the combined radiative effect of biomass burning aerosol and mineral dust usually observed there during that time of the year, when mineral dust emerging from the Sahara mixes with biomass burning aerosol transported north-westwards from the Sahelian region. Our measurements were part of the Saharan Mineral Dwst Experiment 2 (SAMUM 2) funded by the German Research Foundation (DFG) as continuation of the SAMUM field experiment in Morocco in 2006. SAMUM 2 is a joint venture of several German research institutes and universities and included both ground based as well as airborne measurements with the DLR Falcon research aircraft. The ground based instrumentation included spectrometers for visible and thermal infrared downwelling radiation, sun photometers, LIDAR and particle impactors while the Falcon was equipped with LIDAR and several instruments for aerosol analysis and sample return. A comparison of the FTIR measurements with radiative transfer simulations yields the expected aerosol forcing in the atmospheric window region after application of a suitable calibration method.

  2. SAM 2 balloon test (stratospheric aerosol measurement)

    NASA Technical Reports Server (NTRS)

    Pepin, T. J.

    1976-01-01

    As a parallel effort to the LACATE balloon experiment a small optical system was constructed to enable a balloon test of a diode filter system similar to the type planned for the Nimbus-G SAM II experiment. The system was called the SAM II Balloon Test. Results of the balloon flight are summarized.

  3. Experimental Measurements of the Effects of Photo-chemical Oxidation on Aerosol Emissions in Aircraft Exhaust

    NASA Astrophysics Data System (ADS)

    Miracolo, M. A.; Presto, A. A.; Hennigan, C. J.; Nguyen, N.; Ranjan, M.; Reeder, A.; Lipsky, E.; Donahue, N. M.; Robinson, A. L.

    2009-12-01

    Many military and commercial airfields are located in non-attainment areas for particulate matter (PM2.5), but the contribution of emissions from in-use aircraft to local and regional PM2.5 concentrations is uncertain. In collaboration with the Pennsylvania Air National Guard 171st Air Refueling Wing, the Carnegie Mellon University (CMU) Mobile Laboratory was deployed to measure fresh and aged emissions from a CFM56-2B1 gas-turbine engine mounted on a KC-135 Stratotanker airframe. The CFM-56 family of engine powers many different types of military and civilian aircraft, including the Boeing 737 and several Airbus models. It is one of the most widely deployed models of engines in the world. The goal of this work was to measure the gas-particle partitioning of the fresh emissions at atmospherically relevant conditions and to investigate the effect of atmospheric oxidation on aerosol loadings as the emissions age. Emissions were sampled from an inlet installed one meter downstream of the engine exit plane and transferred into a portable smog chamber via a heated inlet line. Separate experiments were conducted at different engine loads ranging from ground idle to take-off rated thrust. During each experiment, some diluted exhaust was added to the chamber and the volatility of the fresh emissions was then characterized using a thermodenuder. After this characterization, the chamber was exposed to either ambient sunlight or UV lights to initiate photochemical oxidation, which produced secondary aerosol and ozone. A suite of gas and particle-phase instrumentation was used to characterize the evolution of the gas and particle-phase emissions, including an aerosol mass spectrometer (AMS) to measure particle size and composition distributions. Fresh emissions of fine particles varied with engine load with peak emission factors at low and high loads. At high engine loads, the fresh emissions were dominated by black carbon; at low loads volatile organic carbon emissions were

  4. Intercomparison of measurement methods for black carbon aerosols

    NASA Astrophysics Data System (ADS)

    Hitzenberger, R.; Jennings, S. G.; Larson, S. M.; Dillner, A.; Cachier, H.; Galambos, Z.; Rouc, A.; Spain, T. G.

    In this study, two method intercomparisons were performed. One thermal and two optical methods for the measurement of black carbon (BC) were applied to laboratory generated aerosols containing only BC. For the optical measurements, an aethalometer (Hansen et al., 1984. Science of Total Environment 36, 191-196) and an integrating sphere technique (Hitzenberger et al., 1996b. Journal of Geophysical Research 101, D14, 19 601-19 606) were used. The thermal method was described by Cachier et al. (1989a. Tellus 41B, 379-390). In an additional comparison, the integrating sphere was compared to a thermal optical technique (Birch and Cary, 1996. Aerosol Science Technology 25, 221-241) on ambient aerosol samples. The absorption coefficients were obtained from transmission measurements on filter samples for both the aethalometer and the integrating sphere. The BC mass concentration for the aethalometer was derived from this absorption measurement. The BC mass concentration for the integrating sphere, however, was obtained using an independent calibration curve. The agreement between the absorption coefficient σa obtained for the BC test aerosol on parallel filters with the aethalometer and the integrating sphere was satisfactory. The slope of the regression lines depended on filter type. A comparison between BC mass concentrations, however, showed that the aethalometer values were only 23% of those obtained by the integrating sphere technique indicating that for pure BC aerosols, the standard aethalometer calibration should not be used. Compared to the thermal method, the integrating sphere gave an overestimation of the BC mass concentrations by 21%. For the ambient samples, the integrating sphere and the thermal optical methods for BC mass concentration determination showed agreement within 5% of the 1 : 1 line, although the data were not so well correlated.

  5. Some results of water vapor, ozone and aerosol balloon borne measurements during EASOE

    NASA Astrophysics Data System (ADS)

    Khattatov, V.; Yushkov, V.; Khaplanov, M.; Zaitzev, I.; Rosen, J.; Kjome, N.

    As part of the European Arctic Stratospheric Ozone Experiment (EASOE) in the northern winter of 1991/92, regular measurements of the vertical distribution of ozone and aerosols were carried out from two Russian polar stations, Heiss Island (81N, 58E) and Dikson Island (73N, 81E). In addition measurements of the vertical distribution of water vapor and aerosols were made from Esrange (68N, 21E), near Kiruna in Sweden. The instruments used were electrochemical ozone sondes (ECC-4A), a fluorescence hygrometer, and the University of Wyoming backscattersonde. Following the eruption of Mt.Pinatubo, in the Philippines, in June 1991, volcanic aerosol had reached Arctic latitudes at altitudes below 19 km by September. At all three sites it was observed on every flight. Polar stratospheric clouds were encountered above the volcanic aerosol on two flights from Esrange. There were no indications of dehydration in the Arctic stratosphere. On all flights the minimum mixing ratio of water vapor was observed 2 to 3 km above the tropopause. Total ozone was much lower than the climatological mean, over Dikson Island from the January 27, and over Heiss Island from mid-February, until the end of EASOE. Ozone profiles over these stations showed rapid increases in partial pressure immediately above the peak values of backscatter ratio when the volcanic aerosol was especially dense.

  6. Characteristics of atmospheric aerosols containing heavy metals measured on Fukue Island, Japan

    NASA Astrophysics Data System (ADS)

    Hidemori, Takehiro; Nakayama, Tomoki; Matsumi, Yutaka; Kinugawa, Takashi; Yabushita, Akihiro; Ohashi, Masafumi; Miyoshi, Takao; Irei, Satoshi; Takami, Akinori; Kaneyasu, Naoki; Yoshino, Ayako; Suzuki, Ryota; Yumoto, Yayoi; Hatakeyama, Shiro

    2014-11-01

    To investigate transport and chemical compositions of fine aerosols in the East Asian region, aerosol chemical components and their mixing states were measured at Fukue Island in the spring of 2010. Off-line chemical analyses using an ion chromatographic analyzer and an inductively coupled plasma-mass spectrometer for the aerosols sampled by a high volume sampler have also been conducted. The mixing state and temporal variation of number concentrations of the particles containing lead (Pb) and vanadium (V) were studied by using a laser ionization single-particle aerosol mass spectrometer (LISPA-MS). The temporal variation of number concentrations of particles containing Pb measured by the LISPA-MS is well consistent with those obtained by the chemical analysis of the aerosols sampled by the high volume sampler. The Pb-containing particles were classified into four types from the statistical analysis on the basis of the single-particle mass spectra with assists of laboratory experiments. It is estimated that 52% of observed particles containing Pb were originated from coal combustion. The concentration-weighted trajectory (CWT) analysis suggests that these particles are mainly transported from China continent. The V-containing particles were classified into three types. The 41% of V-containing particles were internally mixed with sea salt and the result of CWT analysis suggests that the potentially anthropogenic V-containing particles possibility emitted from ships are mixing with sea salt in the region that is highly loaded with sea salt in the Pacific Ocean.

  7. Measurements of ocean derived aerosol off the coast of California

    NASA Astrophysics Data System (ADS)

    Bates, T. S.; Quinn, P. K.; Frossard, A. A.; Russell, L. M.; Hakala, J.; PetäJä, T.; Kulmala, M.; Covert, D. S.; Cappa, C. D.; Li, S.-M.; Hayden, K. L.; Nuaaman, I.; McLaren, R.; Massoli, P.; Canagaratna, M. R.; Onasch, T. B.; Sueper, D.; Worsnop, D. R.; Keene, W. C.

    2012-06-01

    Reliable characterization of particles freshly emitted from the ocean surface requires a sampling method that is able to isolate those particles and prevent them from interacting with ambient gases and particles. Here we report measurements of particles directly emitted from the ocean using a newly developed in situ particle generator (Sea Sweep). The Sea Sweep was deployed alongside R/V Atlantis off the coast of California during May of 2010. Bubbles were generated 0.75 m below the ocean surface with stainless steel frits and swept into a hood/vacuum hose to feed a suite of aerosol instrumentation on board the ship. The number size distribution of the directly emitted, nascent particles had a dominant mode at 55-60 nm (dry diameter) and secondary modes at 30-40 nm and 200-300 nm. The nascent aerosol was not volatile at 230°C and was not enriched in SO4=, Ca++, K+, or Mg++above that found in surface seawater. The organic component of the nascent aerosol (7% of the dry submicrometer mass) volatilized at a temperature between 230 and 600°C. The submicrometer organic aerosol characterized by mass spectrometry was dominated by non-oxygenated hydrocarbons. The nascent aerosol at 50, 100, and 145 nm dry diameter behaved hygroscopically like an internal mixture of sea salt with a small organic component. The CCN/CN activation ratio for 60 nm Sea Sweep particles was near 1 for all supersaturations of 0.3 and higher indicating that all of the particles took up water and grew to cloud drop size. The nascent organic aerosol mass fraction did not increase in regions of higher surface seawater chlorophyll but did show a positive correlation with seawater dimethylsulfide (DMS).

  8. Measurements of ocean derived aerosol off the coast of California

    NASA Astrophysics Data System (ADS)

    Bates, T. S.; Quinn, P. K.; Frossard, A. A.; Russell, L. M.; Hakala, J.; PetäJä, T.; Kulmala, M.; Covert, D. S.; Cappa, C. D.; Li, S.-M.; Hayden, K. L.; Nuaaman, I.; McLaren, R.; Massoli, P.; Canagaratna, M. R.; Onasch, T. B.; Sueper, D.; Worsnop, D. R.; Keene, W. C.

    2011-11-01

    Reliable characterization of particles freshly emitted from the ocean surface requires a sampling method that is able to isolate those particles and prevent them from interacting with ambient gases and particles. Here we report measurements of particles directly emitted from the ocean using a newly developed in situ particle generator (Sea Sweep). The Sea Sweep was deployed alongside R/V Atlantis off the coast of California during May of 2010. Bubbles were generated 0.75 m below the ocean surface with stainless steel frits and swept into a hood/vacuum hose to feed a suite of aerosol instrumentation on board the ship. The number size distribution of the directly emitted, nascent particles had a dominant mode at 55-60 nm (dry diameter) and secondary modes at 30-40 nm and 200-300 nm. The nascent aerosol was not volatile at 230°C and was not enriched in SO4=, Ca++, K+, or Mg++above that found in surface seawater. The organic component of the nascent aerosol (7% of the dry submicrometer mass) volatilized at a temperature between 230 and 600°C. The submicrometer organic aerosol characterized by mass spectrometry was dominated by non-oxygenated hydrocarbons. The nascent aerosol at 50, 100, and 145 nm dry diameter behaved hygroscopically like an internal mixture of sea salt with a small organic component. The CCN/CN activation ratio for 60 nm Sea Sweep particles was near 1 for all supersaturations of 0.3 and higher indicating that all of the particles took up water and grew to cloud drop size. The nascent organic aerosol mass fraction did not increase in regions of higher surface seawater chlorophyll but did show a positive correlation with seawater dimethylsulfide (DMS).

  9. Eddy Covariance Measurements of the Sea-Spray Aerosol Flu

    NASA Astrophysics Data System (ADS)

    Brooks, I. M.; Norris, S. J.; Yelland, M. J.; Pascal, R. W.; Prytherch, J.

    2015-12-01

    Historically, almost all estimates of the sea-spray aerosol source flux have been inferred through various indirect methods. Direct estimates via eddy covariance have been attempted by only a handful of studies, most of which measured only the total number flux, or achieved rather coarse size segregation. Applying eddy covariance to the measurement of sea-spray fluxes is challenging: most instrumentation must be located in a laboratory space requiring long sample lines to an inlet collocated with a sonic anemometer; however, larger particles are easily lost to the walls of the sample line. Marine particle concentrations are generally low, requiring a high sample volume to achieve adequate statistics. The highly hygroscopic nature of sea salt means particles change size rapidly with fluctuations in relative humidity; this introduces an apparent bias in flux measurements if particles are sized at ambient humidity. The Compact Lightweight Aerosol Spectrometer Probe (CLASP) was developed specifically to make high rate measurements of aerosol size distributions for use in eddy covariance measurements, and the instrument and data processing and analysis techniques have been refined over the course of several projects. Here we will review some of the issues and limitations related to making eddy covariance measurements of the sea spray source flux over the open ocean, summarise some key results from the last decade, and present new results from a 3-year long ship-based measurement campaign as part of the WAGES project. Finally we will consider requirements for future progress.

  10. Direct aerosol chemical composition measurements to evaluate the physicochemical differences between controlled sea spray aerosol generation schemes

    NASA Astrophysics Data System (ADS)

    Collins, D. B.; Zhao, D. F.; Ruppel, M. J.; Laskina, O.; Grandquist, J. R.; Modini, R. L.; Stokes, M. D.; Russell, L. M.; Bertram, T. H.; Grassian, V. H.; Deane, G. B.; Prather, K. A.

    2014-11-01

    Controlled laboratory studies of the physical and chemical properties of sea spray aerosol (SSA) must be under-pinned by a physically and chemically accurate representation of the bubble-mediated production of nascent SSA particles. Bubble bursting is sensitive to the physico-chemical properties of seawater. For a sample of seawater, any important differences in the SSA production mechanism are projected into the composition of the aerosol particles produced. Using direct chemical measurements of SSA at the single-particle level, this study presents an intercomparison of three laboratory-based, bubble-mediated SSA production schemes: gas forced through submerged sintered glass filters ("frits"), a pulsed plunging-waterfall apparatus, and breaking waves in a wave channel filled with natural seawater. The size-resolved chemical composition of SSA particles produced by breaking waves is more similar to particles produced by the plunging waterfall than those produced by sintered glass filters. Aerosol generated by disintegrating foam produced by sintered glass filters contained a larger fraction of organic-enriched particles and a different size-resolved elemental composition, especially in the 0.8-2 μm dry diameter range. Interestingly, chemical differences between the methods only emerged when the particles were chemically analyzed at the single-particle level as a function of size; averaging the elemental composition of all particles across all sizes masked the differences between the SSA samples. When dried, SSA generated by the sintered glass filters had the highest fraction of particles with spherical morphology compared to the more cubic structure expected for pure NaCl particles produced when the particle contains relatively little organic carbon. In addition to an intercomparison of three SSA production methods, the role of the episodic or "pulsed" nature of the waterfall method on SSA composition was under-taken. In organic-enriched seawater, the continuous

  11. Evaluation of Aerosol Properties in GCMs using Satellite Measurements

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Jiang, J. H.; Su, H.; Zhang, H.

    2015-12-01

    Atmospheric aerosols from natural or anthropogenic sources have profound impacts on the regional and global climate. Currently the radiative forcing of aerosols predicted by global climate models remains highly uncertain, representing the largest uncertainty in climate predictions. The uncertainty mainly arises from the complicated aerosol chemical and physical properties, coarse emission inventories for pre-cursor gases as well as unrealistic representations of aerosol activation and cloud processing in global climate models. In this study, we will utilize multiple satellite measurements including MODIS, MISR and CALIPSO to quantitatively evaluate aerosol simulations from climate models. Our analyses show that the global means in AOD climatology from NCAR CAM5 and GFDL AM3 simulations are comparable with satellite measurements. However, the overall correlation coefficient between the AOD spatial patterns from CAM5 and satellite is only 0.4. Moreover, at finer scales, the magnitude of AOD in CAM5 is much lower than satellite measurements for most of the non-dust regions, especially over East Asia. GFDL AM3 shows better AOD simulations over East Asia. The underestimated AOD over remote maritime areas in CAM5 was attributed to the unrealistic wet removal processes in convective clouds of CAM5. Over continents, biases on AOD could stem from underestimations in the emissions inventory and unresolved sub-grid variations of relative humidity due to the model's coarse resolution. Uncertainty from emission inventory over developing countries in East Asia will be assessed using the newly updated Regional Emission inventory in Asia (REAS) and Multi-resolution Emission Inventory in China (MEIC) in the model simulations.

  12. Stratospheric Sulfuric Acid and Black Carbon Aerosol Measured During POLARIS and its Role in Ozone Chemistry

    NASA Technical Reports Server (NTRS)

    Strawa, Anthony W.; Pueschel, R. F.; Drdla, K.; Verma, S.; Gore, Warren J. (Technical Monitor)

    1998-01-01

    Stratospheric aerosol can affect the environment in three ways. Sulfuric acid aerosol have been shown to act as sites for the reduction of reactive nitrogen and chlorine and as condensation sites to form Polar Stratospheric Clouds, under very cold conditions, which facilitate ozone depletion. Recently, modeling studies have suggested a link between BCA (Black Carbon Aerosol) and ozone chemistry. These studies suggest that HNO3, NO2, and O3 may be reduced heterogeneously on BCA particles. The ozone reaction converts ozone to oxygen molecules, while HNO3 and NO2 react to form NOx. Finally, a buildup of BCA could reduce the single-scatter albedo of aerosol below a value of 0.98, a critical value that has been postulated to change the effect of stratospheric aerosol from cooling to warming. Correlations between measured BCA amounts and aircraft usage have been reported. Attempts to link BCA to ozone chemistry and other stratospheric processes have been hindered by questions concerning the amount of BCA that exists in the stratosphere, the magnitude of reaction probabilities, and the scarcity of BCA measurements. The Ames Wire Impactors (AWI) participated in POLARIS as part of the complement of experiments on the NASA ER-2. One of our main objectives was to determine the amount of aerosol surface area, particularly BCA, available for reaction with stratospheric constituents and assess if possible, the importance of these reactions. The AWI collects aerosol and BCA particles on thin Palladium wires that are exposed to the ambient air in a controlled manner. The samples are returned to the laboratory for subsequent analysis. The product of the AWI analysis is the size, surface area, and volume distributions, morphology and elemental composition of aerosol and BCA. This paper presents results from our experiments during POLARIS and puts these measurements in the context of POLARIS and other missions in which we have participated. It describes modifications to the AWI data

  13. A global aerosol model forecast for the ACE-Asia field experiment

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

    We present the results of aerosol forecast during the 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 model provides direct information on aerosol optical thickness and concentrations for effective flight planning, while feedbacks from measurements constantly evaluate the model for successful model improvements. We verify the model forecast skill by comparing model-predicted aerosol quantities and meteorological variables with those measured by the C-130 aircraft. The GEOS DAS meteorological forecast system shows excellent skills in predicting winds, relative humidity, and temperature, with skill scores usually in the range of 0.7-0.99. The model is also skillful in forecasting 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 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 boundary layer high dust concentrations over the Yellow Sea. We demonstrate that our global model can not only account for the large-scale intercontinental transport but also produce the small-scale spatial and temporal variations that are adequate for aircraft measurements planning.

  14. Measurements of Natural Radioactivity in Submicron Aerosols in Mexico City.

    NASA Astrophysics Data System (ADS)

    Gaffney, J. S.; Marley, N. A.; Sterling, K.; Sturchio, N. C.

    2003-12-01

    Natural radionuclides can be useful in evaluating the transport of ozone and aerosols in the troposphere. Beryllium-7, which is produced by cosmic ray interactions in the upper troposphere and lower stratosphere and becomes adsorbed on fine aerosols, can be a useful indicator of upper air transport into a region. Lead-210 is produced by the decay of radon-222 out-gassed into the lower atmosphere from ground-based uranium deposits. Potassium-40, found in soils, can act as a measure of wind-blown dust and also comes from burning of wood and other biomass that is enriched in this natural radioisotope. Thus, both lead-210 and potassium-40 can aid in identification of aerosols sourced in the lower atmosphere. As part of our continuing interest in the lifetimes and sources of aerosols and their radiative effects, we report here measurements of fine aerosol radioactivity in Mexico City, one of the largest megacities in the world. Samples were collected on quartz fiber filters by using cascade impactors (Sierra type, Anderson Instruments) and high-volume air samplers from the rooftop of the main laboratory of El Centro Nacional de Investigacion y Capacitacion Ambiental (CENICA). By using stage 4 of the impactor and timers, we were able to collect integrated samples of sizes > 1 micrometer and < 1 micrometer over 12-hr time periods daily for approximately one month in April 2003. Samples were counted at the University of Illinois at Chicago by using state-of-the-art gamma counting (beryllium-7, 477.6 keV; potassium-40, 1460.8 keV; lead-210, 46.5 keV). The beryllium-7 data indicate one possible upper-air transport event during April 2003. As expected, the lead-210 data indicate very little soil contribution to the fine aerosol. The potassium-40 data showed an increase in fine aerosol potassium during Holy Week that might be attributed to local combustion of biomass fuels. The data will be presented and discussed in light of future data analysis and comparison with other

  15. Aerosol mass spectrometry: particle-vaporizer interactions and their consequences for the measurements

    NASA Astrophysics Data System (ADS)

    Drewnick, F.; Diesch, J.-M.; Faber, P.; Borrmann, S.

    2015-04-01

    The Aerodyne Aerosol Mass Spectrometer (AMS) is a frequently used instrument for on-line measurement of the ambient sub-micron aerosol composition. With the help of calibrations and a number of assumptions on the flash vaporization and electron impact ionization processes this instrument provides robust quantitative information on various ambient aerosol components. However, when measuring close to certain anthropogenic sources or in marine environments, several of these assumptions may not be met and measurement results might easily be misinterpreted. Here we discuss various aspects of the interaction of aerosol particles with the AMS tungsten vaporizer and the consequences for the measurement results: semi-refractory components, i.e. components that vaporize but do not flash vaporize at the vaporizer and ionizer temperatures, like metal halides (e.g. chlorides, bromides or iodides of Al, Ba, Cd, Cu, Fe, Hg, K, Na, Pb, Sr, Zn) can be measured semi-quantitatively despite their relatively slow vaporization from the vaporizer. Even though non-refractory components (e.g. NH4NO3 or (NH4)2SO4) vaporize quickly, their differences in vaporization kinetics can result in undesired biases in ion collection efficiency in the measurements. Chemical reactions with water vapor and oxygen from the aerosol flow can have an influence on the mass spectra for certain components (e.g. NH4NO3, (NH4)2SO4, organic species). Finally, chemical reactions of the aerosol with the vaporizer surface can result in additional signals in the mass spectra (e.g. WO2C2-related signals from particulate Cl) and in conditioning or contamination of the vaporizer with potential memory effects influencing the mass spectra of subsequent measurements. Laboratory experiments that investigate these particle-vaporizer interactions are presented and are discussed together with field results showing that measurements of typical continental or urban aerosols are not significantly affected while laboratory

  16. The analysis of in situ and retrieved aerosol properties measured during three airborne field campaigns

    NASA Astrophysics Data System (ADS)

    Corr, Chelsea A.

    actinic flux (AF SSA) to those retrieved using ratios of direct and diffuse irradiance (DDR SSA) at four wavelengths: 332, 368, 415, and 500 mn. Both actinic flux and irradiance were measured atop the University of Houston's Moody Tower in Houston, TX as part of the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) mission in September 2013. AF SSA values were consistently lower than DDR SSAs with largest offsets observed when aerosol optical depths was < ~0.2. AF SSA were also lower than those reported by the AErosol RObotic NETwork (AERONET) and column-averaged values calculated from aerosol scattering and absorption coefficients measured aboard the NASA P3-B aircraft at 450 and 550 nm. However, AAE values calculated from AF SSAs compared well to AERONET and column-averaged AAEs suggesting actinic flux retrievals can correctly resolve the spectral dependence of aerosol absorption. Recent work has suggested that mineral dust is the most important IN found in both anvil and synoptically formed cirrus clouds over North America. The vertical transport processes sustaining significant mineral dust in the upper troposphere (> 9 km) where these clouds form are not well understood, but deep convective systems (thunder storms) likely play a role. Bulk aerosol Ca2+ concentrations and volume size distributions were measured aboard the NASA DC-8 during the NCAR Deep Convective Clouds and Chemistry Experiment (DC-3) conducted in May/June 2012 in both the inflow and outflow regions of twelve isolated, high cloud base storms over CO and OK. Outflow/inflow ratios of both Ca2+ and total coarse (limn < diameter < 5 microm) aerosol volume (Vc)were high (> ~0.9) suggesting a significant fraction of ingested coarse mode dust was transported through these systems. Elevated Ca2+ and Vc in the outflow were most likely not artifacts of ice shattering given the general absence of a relationship between these

  17. Residual oil aerosol measurements on refrigerators and liquefiers

    NASA Astrophysics Data System (ADS)

    Pflueckhahn, D.; Anders, W.; Hellwig, A.; Knobloch, J.; Rotterdam, S.

    2014-01-01

    The purity of the process gas is essential for the reliability of refrigerators and liquefiers. Filtration and adsorption of impurities like water, nitrogen, and oil result in a major effort, cost, and maintenance in the helium process. Expensive impurity monitors for moisture, nitrogen, and hydrocarbon contents are required to identify filter failures and leakage immediately during the operation. While water and nitrogen contaminants can be detected reliably, the measurement of oil aerosols at the ppb-level is challenging. We present a novel diagnostic oil aerosol measurement system able to measure particles in the sub-μm range. This unit enabled us to evaluate and improve the oil separation system on a LINDE TCF 50 helium liquefier.

  18. 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.

  19. Light source effects on aerosol photoacoustic spectroscopy measurements

    NASA Astrophysics Data System (ADS)

    Radney, James G.; Zangmeister, Christopher D.

    2017-01-01

    Photoacoustic spectroscopy measurements of flame-generated soot aerosol coated with small amounts of water yielded absorption enhancements that were dependent on the laser used: quasi-continuous wave (Q-CW, ≈650 ps pulse duration and 78 MHz repetition rate) versus continuous wave (CW). Water coating thickness was controlled by exposing the aerosol to a set relative humidity (RH). At ≈85% RH, the mass of the soot particles increased by an amount comparable to a monolayer of water being deposited and enhanced the measured absorption by 36% and 15% for the Q-CW and CW lasers, respectively. Extinction measurements were also performed using a cavity ring-down spectrometer (extinction equals the sum of absorption and scattering) with a CW laser and negligible enhancement was observed at all RH. These findings demonstrate that source choice can impact measurements of aerosols with volatile coatings and that the absorption enhancements at high RH previously measured by Radney and Zangmeister [1] are the result of laser source used (Q-CW) and not from an increase in the particle absorption cross section.

  20. Establishing aerosol exposure predictive models based on vibration measurements.

    PubMed

    Soo, Jhy-Charm; Tsai, Perng-Jy; Lee, Shih-Chuan; Lu, Shih-Yi; Chang, Cheng-Ping; Liou, Yuh-When; Shih, Tung-Sheng

    2010-06-15

    This paper establishes particulate exposure predictive models based on vibration measurements under various concrete drilling conditions. The whole study was conducted in an exposure chamber using a full-scale mockup of concrete drilling simulator to simulate six drilling conditions. For each drilling condition, the vibration of the three orthogonal axes (i.e., a(x), a(y), and a(z)) was measured from the hand tool. Particulate exposure concentrations to the total suspended particulate (C(TSP)), PM(10) (C(PM10)), and PM(2.5) (C(PM2.5)) were measured at the downwind side of the drilling simulator. Empirical models for predicting C(TSP), C(PM10) and C(PM2.5) were done based on measured a(x), a(y), and a(z) using the generalized additive model. Good agreement between measured aerosol exposures and vibrations was found with R(2)>0.969. Our results also suggest that a(x) was mainly contributed by the abrasive wear. On the other hand, a(y) and a(z) were mainly contributed by both the impact wear and brittle fracture wear. The approach developed from the present study has the potential to provide a cheaper and convenient method for assessing aerosol exposures from various emission sources, particularly when conducting conventional personal aerosol samplings are not possible in the filed.

  1. Aerosol variability over the Mediterranean basin from 2005-2012 POLDER-3/PARASOL and AERONET/PHOTONS measurements

    NASA Astrophysics Data System (ADS)

    Chiapello, Isabelle; Ducos, Fabrice; Dulac, François; Léon, Jean-François; Mallet, Marc; Tanré, Didier; Goloub, Philippe

    2013-04-01

    POLDER-3 (Polarization and Directionnality of the Earth's Reflectances) has been launched on board the PARASOL microsatellite in December 2004. Although the PARASOL orbit has been lowered twice (in September 2009 and in November 2011) compared to the other platforms of the A-Train constellation, POLDER observations continue, providing now more than seven years of innovative retrievals of aerosol properties from space. In this study we focus on analyzing POLDER-3 capabilities to derive both aerosol loads (Total Aerosol Optical Thickness) and size properties (fine and coarse spherical/non-spherical Aerosol Optical Thickness, Angström coefficients) over oceanic surfaces. This analysis, as part of the ChArMEx (the Chemistry-Aerosol Mediterranean Experiment) program, focus on the Mediterranean basin, a region under the influence of a complex mixture of aerosols from different sources. Especially we aim to investigate the respective contributions of (i) pollution aerosols (emitted by industry and urban environments of some European regions or megacities surrounding the basin), (ii) carbonaceous particles (from biomass burning events), (iii) mineral dust exported from arid and semi-arid regions of North Africa. In a first step, our study consists in an analysis of aerosol variability retrieved from AERONET/PHOTONS photometer records from selected sites located in Western part of the Mediterranean basin (i.e., Soust-East of France, Spain, Corsica/Sardinia), as well as central part (i.e., Italia and Lampedusa), and Eastern part (i.e.,Greece and Turkey). These measurements provide a unique characterization of both aerosol load (aerosol optical depth) and properties (size distribution and absorption though single scattering albedo) and their temporal variability over each part of the Mediterranean basin. The second step focus on a regional validation of the PARASOL monthly aerosol products by comparison with these equivalent and selected ground-based AERONET

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

    NASA Astrophysics Data System (ADS)

    Milbrath, Brian

    2004-05-01

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

  3. MAX-DOAS Measurements of Nitrogen Dioxide and Aerosol

    NASA Astrophysics Data System (ADS)

    Mendolia, Deanna

    Multi-axis differential optical absorption spectroscopy (MAX-DOAS) was applied to retrieve tropospheric NO2 and aerosol vertical profiles from downtown Toronto, and King City, Ontario during select periods in 2006 - 2010. Linear regression of MAX-DOAS NO2 vertical column density (VCD) versus OMI (satellite) VCD yielded a good correlation (R = 0.88) and MAX-DOAS negative bias of 20%, which was within the reported uncertainty of the MAX-DOAS and OMI VCD. The average regional Toronto VCD (remotely-sensed via MAX-DOAS and OMI) was half of the near-road VCD obtained in-situ (2.4 x 1016 ± 1.2 x 1016 molec/cm2 ). MAX-DOAS measurements of O4 were coupled with radiative transfer modeling to obtain vertical aerosol extinction profiles and aerosol optical depth (AOD). A strong linear agreement was observed between PM 2.5 concentration and aerosol extinction coefficient (R = 0.92), and MAX-DOAS versus sun photometer AOD (slope = 0.94; R= 0.90).

  4. Confined Aerosol Jet in Fiber Classification and Dustiness Measurement

    NASA Astrophysics Data System (ADS)

    Dubey, Prahit

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

  5. Measurement of the Vertical Distribution of Aerosol by Globally Distributed MP Lidar Network Sites

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    The global distribution of aerosol has an important influence on climate through the scattering and absorption of shortwave radiation and through modification of cloud optical properties. Current satellite and other data already provide a great amount of information on aerosol distribution. However there are critical parameters that can only be obtained by active optical profiling. For aerosol, no passive technique can adequately resolve the height profile of aerosol. The aerosol height distribution is required for any model for aerosol transport and the height resolved radiative heating/cooling effect of aerosol. The Geoscience Laser Altimeter System (GLAS) is an orbital lidar to be launched by 2002. GLAS will provide global measurements of the height distribution of aerosol. The sampling will be limited by nadir only coverage. There is a need for local sites to address sampling, and accuracy factors. Full time measurements of the vertical distribution of aerosol are now being acquired at a number of globally distributed MP (micro pulse) lidar sites. The MP lidar systems provide profiling of all significant cloud and aerosol to the limit of signal attenuation from compact, eye safe instruments. There are currently six sites in operation and over a dozen planned. At all sites there are a complement of passive aerosol and radiation measurements supporting the lidar data. Four of the installations are at Atmospheric Radiation Measurement program sites. The aerosol measurements, retrievals and data products from the network sites will be discussed. The current and planned application of data to supplement satellite aerosol measurements is covered.

  6. AeroCom INSITU Project: Comparing modeled and measured aerosol optical properties

    NASA Astrophysics Data System (ADS)

    Andrews, Elisabeth; Schmeisser, Lauren; Schulz, Michael; Fiebig, Markus; Ogren, John; Bian, Huisheng; Chin, Mian; Easter, Richard; Ghan, Steve; Kokkola, Harri; Laakso, Anton; Myhre, Gunnar; Randles, Cynthia; da Silva, Arlindo; Stier, Phillip; Skeie, Ragnehild; Takemura, Toshihiko; van Noije, Twan; Zhang, Kai

    2016-04-01

    AeroCom, an open international collaboration of scientists seeking to improve global aerosol models, recently initiated a project comparing model output to in-situ, surface-based measurements of aerosol optical properties. The model/measurement comparison project, called INSITU, aims to evaluate the performance of a suite of AeroCom aerosol models with site-specific observational data in order to inform iterative improvements to model aerosol modules. Surface in-situ data has the unique property of being traceable to physical standards, which is an asset in accomplishing the overall goal of bettering the accuracy of aerosols processes and the predicative capability of global climate models. Here we compare dry, in-situ aerosol scattering and absorption data from ~75 surface, in-situ sites from various global aerosol networks (including NOAA, EUSAAR/ACTRIS and GAW) with a simulated optical properties from a suite of models participating in the AeroCom project. We report how well models reproduce aerosol climatologies for a variety of time scales, aerosol characteristics and behaviors (e.g., aerosol persistence and the systematic relationships between aerosol optical properties), and aerosol trends. Though INSITU is a multi-year endeavor, preliminary phases of the analysis suggest substantial model biases in absorption and scattering coefficients compared to surface measurements, though the sign and magnitude of the bias varies with location. Spatial patterns in the biases highlight model weaknesses, e.g., the inability of models to properly simulate aerosol characteristics at sites with complex topography. Additionally, differences in modeled and measured systematic variability of aerosol optical properties suggest that some models are not accurately capturing specific aerosol behaviors, for example, the tendency of in-situ single scattering albedo to decrease with decreasing aerosol extinction coefficient. The endgoal of the INSITU project is to identify specific

  7. How Well Can Aerosol Measurements from the Terra Morning Polar Orbiting Satellite Represent the Daily Aerosol Abundance and Properties?

    NASA Technical Reports Server (NTRS)

    Kaufman, Y. J.; Holben, B. N.; Tanre, D.; Slutzker, I.; Eck, T. F.; Smirnov, A.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The Terra mission, launched at the dawn of 1999, and Aqua mission to be launched soon, will possess innovative measurements of the aerosol daily spatial distribution, distinguish between dust, smoke and regional pollution and measure aerosol radiative forcing of climate. Their polar orbit gives daily global coverage, however measurements are acquired at specific time of the day. To what degree can present measurements from Terra taken between 10:00 and 11:30 AM local time, represent the daily average aerosol forcing of climate? Here we answer this question using 7 years of data from the distributed ground based 50-70 instrument Aerosol Robotic Network (AERONET) This (AERONET) half a million measurement data set shows that Terra aerosol measurements represent the daily average values within 5%. The excellent representation is found for large dust particles or small aerosol particles from Fires or regional pollution and for any range of the optical thickness, a measure of the amount of aerosol in the atmosphere.

  8. In-situ, quantitative speciation of aerosols over Pasadena, CA during the CalNex 2010 experiment

    NASA Astrophysics Data System (ADS)

    Isaacman, G. A.; Worton, D. R.; Kreisberg, N. M.; Zhao, Y.; Hering, S. V.; Goldstein, A.

    2010-12-01

    Concentrations of over 200 compounds were quantified and several hundred more were observed in organic aerosols over Pasadena, CA using the GCxGC Thermal Desorption Aerosol Gas Chromatograph/Mass Spectrometer (2D-TAG) during the California at the Nexus between Air Quality and Climate Change (CalNex) Experiment in the summer of 2010. In order to improve quantitation, we incorporated recent improvements to the 2D-TAG instrument (detailed in Worton, et al., in prep), including valveless injection and an automated system for addition of deuterated internal standards. Measured compounds span a wide range of volatility and functionality, including alkanes and cycloalkanes, alkenes, furanones, ketones, nitriles, phthalic acids and anhydrides, polycyclic aromatic hydrocarbons (PAHs), branched PAHs, and oxygenated PAHs, as well as known tracers for a variety of sources, such as secondary organic aerosol (SOA), diesel fuel, and biomass burning. These compounds represent not only fresh emissions, but also aged and slightly oxidized pollutants. Though most of these compounds have been quantified in the atmosphere in previous experiments, this represents the first multi-day, in-situ measurement of ambient urban aerosols using two-dimensional chromatography. The high time-resolution of these measurements allows for statistically significant analysis of the diurnal variability and covariance of these compounds, which will be used to better understand source profiles and attribute sources. Furthermore, because many of the observed compounds have been shown to be correlated with accepted Aerodyne Aerosol Mass Spectrometer (AMS) factors (hydrocarbon-like organic aerosol, oxygenated organic aerosol, etc.), the data presented here will provide a better understanding of the composition of these factors in an urban environment. Putting this work into the context of the extensive suite of data from the Pasadena site will greatly contribute to our understanding of urban aerosol sources

  9. Aerosol and gamma background measurements at Basic Environmental Observatory Moussala

    NASA Astrophysics Data System (ADS)

    Angelov, Christo; Arsov, Todor; Penev, Ilia; Nikolova, Nina; Kalapov, Ivo; Georgiev, Stefan

    2016-03-01

    Trans boundary and local pollution, global climate changes and cosmic rays are the main areas of research performed at the regional Global Atmospheric Watch (GAW) station Moussala BEO (2925 m a.s.l., 42°10'45'' N, 23°35'07'' E). Real time measurements and observations are performed in the field of atmospheric chemistry and physics. Complex information about the aerosol is obtained by using a threewavelength integrating Nephelometer for measuring the scattering and backscattering coefficients, a continuous light absorption photometer and a scanning mobile particle sizer. The system for measuring radioactivity and heavy metals in aerosols allows us to monitor a large scale radioactive aerosol transport. The measurements of the gamma background and the gamma-rays spectrum in the air near Moussala peak are carried out in real time. The HYSPLIT back trajectory model is used to determine the origin of the data registered. DREAM code calculations [2] are used to forecast the air mass trajectory. The information obtained combined with a full set of corresponding meteorological parameters is transmitted via a high frequency radio telecommunication system to the Internet.

  10. Aerosol Particle Interfacial Thermodynamics and Phase Partitioning Measurements Using Biphasic Microfluidics

    NASA Astrophysics Data System (ADS)

    Dutcher, Cari; Metcalf, Andrew

    2015-03-01

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

  11. Aircraft measurements of aerosols in the upper troposphere at midlatitudes

    NASA Technical Reports Server (NTRS)

    Morita, Y.; Takagi, M.; Kondo, Y.

    1985-01-01

    Aircraft measurements of aerosols were made during the years 1982 to 1984 in the upper troposphere. In some cases, the influence of the local atmospheric pollution originating from the land surface was observed. The background concentration of the Mie particle was about 0.1/cu. cm. at an altitude of 6 to 8 km. An air mass of stratospheric origin was observed over the Japan sea in the winters of 1983 and 1984. The Mie particle concentration increased and the count ratio of two size ranges was found to be a large value in 1983, the value decreased to that of a background level in the stratosphere in 1984. The volcanic eruption of Mt. El Chichon seems to be responsible for the large aerosol count ratio of the measurements of 1983.

  12. An Overview of the Nighttime Aerosol/Oxidant Plume Experiment (NAOPEX)

    SciTech Connect

    Berkowitz, Carl M.; Zaveri, Rahul A.; Hubbe, John M.; Springston, Stephen R.; Coulter, Richard L.

    2003-12-01

    The Nighttime Aerosol/Oxidant Plume Experiment was designed to characterize aerosols (number density, geographic distribution, physical characteristics) and trace gases coming from the greater Boston area at night between July 29 and August 8, 2002. Aircraft flights below 1500m MSL measured upwind/downwind characteristics of the urban plume and included Lagrangian measurements made in conjunction with tetroon releases within the plume. We focus here on just the upwind/downwind characeristics of the plume, with the Lagrangian results to be presented elsewhere. Statistically insignificant variations in aerosol number density, O3, and CO downwind of Boston were found under conditions of westerly flow, although large (50%) increases in downwind NOy were measured. Much bigger upwind/downwind differences were found in O3 and CO when sampling under light and variable wind conditions although the downwind NOy levels were much less (increase of only 15%), and were not associated with any measurable increase in the NOx relative to observations made under westerly flow. There was, in general, little evidence of the Boston plume at aircraft sampling heights, which suggests a greatly reduced potential for long range transport of the urban plume within the free troposphere over the Atlantic.

  13. Light water reactor aerosol containment experiment LA4 simulated by JERICHO and AEROSOLS-B2 codes

    SciTech Connect

    Passalacqua, R.; Tarabelli, D.; Renault, C.

    1996-12-01

    Large-scale experiments show that whenever a loss of coolant accident occurs water pools are generated. Stratification of steam-saturated gas develops above growing water pools causing a different thermal hydraulics in the subcompartment where the water pool is located. Hereafter, the LWR Aerosols Containment Experiment (LACE) LA4 experiment, performed at the Hanford Engineering Development Laboratory, will be studied; this experiment exhibited a strong stratification, at all times, above a growing wade pool. JERICHO and AEROSOLS-B2 are part of the Ensemble de Systemes de Codes d`Analyse d`Accident des Reacteurs a Eau (ESCADRE) code system, a tool for evaluating the response of a nuclear plant to severe accidents. These two codes are used here to simulate respectively the thermal hydraulics and the associated aerosol behavior. Code results have shown that modeling large containment thermal hydraulics without taking into account the stratification phenomenon leads to large overpredictions of containment pressure and temperature. If the stratification, above the water pool, is modeled as a zone with a higher steam condensation rate and a higher thermal resistance (that is acting as a barrier to heat exchanges with the upper and larger compartment), ESCADRE predictions match experimental data quite well. The stratification region is believed to be able to affect aerosol behavior; aerosol settling is improved by steam condensation on particles and by diffusiophoresis and thermophoresis. In addition, the lower aerosol concentration throughout the stratification might cause a nonnegligible aerosol concentration gradient and consequently a driving force for the motion of smaller particles toward the pool.

  14. Airborne measurements of hygroscopicity and mixing state of aerosols in the planetary boundary layer during the PEGASOS campaigns

    NASA Astrophysics Data System (ADS)

    Rosati, Bernadette; Weingartner, Ernest; Gysel, Martin; Rubach, Florian; Mentel, Thomas; Baltensperger, Urs

    2014-05-01

    Aerosols interact directly with the incident solar radiation by scattering or absorbing the light. The optical properties of an aerosol particle can strongly be altered at enhanced relative humidity (RH). Depending on the particle's chemical composition, it can experience hygroscopic growth, leading to a change in size and index of refraction compared to the dry particle (Zieger et al., 2011). Besides, aerosols can exist in different mixing states which are usually divided into internal and external mixtures. If all particles of a certain size have the same chemical composition, they are described as internally mixed, whereas if particles of equal size have different chemical composition, they are defined as externally mixed. Depending on the mixture the hygroscopic behavior will change: internally mixed aerosols will grow uniformly with increasing RH, while the different substances in external mixtures will experience different growing behaviors leading to a mode-splitting or broadened size distribution. Laboratory studies are commonly performed at dry conditions but it is known that temperature and RH as well as chemical composition are changing with altitude (Morgan et al., 2010). This further leads to the conclusion that the in-situ measurements of optical properties at different heights are crucial for climate forcing calculations. Within the Pan-European Gas-Aerosols-climate interaction Study (PEGASOS) the white- light humidified optical particle spectrometer (WHOPS) was developed and installed on the Zeppelin to investigate changes of light scattering with regard to water uptake and altitude. This instrument firstly selects a dry monodisperse aerosol by its electrical mobility and then exposes it to a well-defined RH (typically 95%). Alternately, the dry and humidified particles are measured in a white-light optical particle spectrometer (WELAS). In this way it is possible to infer the effective index of refraction of the dry particles, their hygroscopic

  15. Comparing Simultaneous Stratospheric Aerosol and Ozone Lidar Measurements with SAGE 2 Data after the Mount Pinatubo Eruption

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Poole, L. R.; McCormick, M. P.; Veiga, R. E.; Wang, P.-H.; Rizi, V.; Masci, F.; DAltorio, A.; Visconti, G.

    1995-01-01

    Stratospheric aerosol and ozone profiles obtained simultaneously from the lidar station at the University of L'Aquila (42.35 deg N, 13.33 deg E, 683 m above sea level) during the first 6 months following the eruption of Mount Pinatubo are compared with corresponding nearby Stratospheric Aerosol and Gas Experiment (SAGE) 2 profiles. The agreement between the two data sets is found to be reasonably good. The temporal change of aerosol profiles obtained by both techniques showed the intrusion and growth of Pinatubo aerosols. In addition, ozone concentration profiles derived from an empirical time-series model based on SAGE 2 ozone data obtained before the Pinatubo eruption are compared with measured profiles. Good agreement is shown in the 1991 profiles, but ozone concentrations measured in January 1992 were reduced relative to time-series model estimates. Possible reasons for the differences between measured and model-based ozone profiles are discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  17. Long term measurements of aerosol optical properties at a primary forest site in Amazonia

    NASA Astrophysics Data System (ADS)

    Rizzo, L. V.; Artaxo, P.; Müller, T.; Wiedensohler, A.; Paixão, M.; Cirino, G. G.; Arana, A.; Swietlicki, E.; Roldin, P.; Fors, E. O.; Wiedemann, K. T.; Leal, L. S. M.; Kulmala, M.

    2013-03-01

    A long term experiment was conducted in a primary forest area in Amazonia, with continuous in-situ measurements of aerosol optical properties between February 2008 and April 2011, comprising, to our knowledge, the longest database ever in the Amazon Basin. Two major classes of aerosol particles, with significantly different optical properties were identified: coarse mode predominant biogenic aerosols in the wet season (January-June), naturally released by the forest metabolism, and fine mode dominated biomass burning aerosols in the dry season (July-December), transported from regional fires. Dry particle median scattering coefficients at the wavelength of 550 nm increased from 6.3 Mm-1 to 22 Mm-1, whereas absorption at 637 nm increased from 0.5 Mm-1 to 2.8 Mm-1 from wet to dry season. Most of the scattering in the dry season was attributed to the predominance of fine mode (PM2) particles (40-80% of PM10 mass), while the enhanced absorption coefficients are attributed to the presence of light absorbing aerosols from biomass burning. As both scattering and absorption increased in the dry season, the single scattering albedo (SSA) did not show a significant seasonal variability, in average 0.86 ± 0.08 at 637 nm for dry aerosols. Measured particle optical properties were used to estimate the aerosol forcing efficiency at the top of the atmosphere. Results indicate that in this primary forest site the radiative balance was dominated by the cloud cover, particularly in the wet season. Due to the high cloud fractions, the aerosol forcing efficiency absolute values were below -3.5 W m-2 in 70% of the wet season days and in 46% of the dry season days. Besides the seasonal variation, the influence of out-of-Basin aerosol sources was observed occasionally. Periods of influence of the Manaus urban plume were detected, characterized by a consistent increase on particle scattering (factor 2.5) and absorption coefficients (factor 5). Episodes of biomass burning and mineral dust

  18. Long term measurements of aerosol optical properties at a pristine forest site in Amazonia

    NASA Astrophysics Data System (ADS)

    Rizzo, L. V.; Artaxo, P.; Müller, T.; Wiedensohler, A.; Paixão, M.; Cirino, G. G.; Arana, A.; Swietlicki, E.; Roldin, P.; Fors, E. O.; Wiedemann, K. T.; Leal, L. S. M.; Kulmala, M.

    2012-09-01

    A long term experiment was conducted in a pristine area in the Amazon forest, with continuous in situ measurements of aerosol optical properties between February 2008 and April 2011, comprising, to our knowledge, the longest database ever in Amazonia. Two types of aerosol particles, with significantly different optical properties were identified: coarse mode predominant biogenic aerosols in the wet season (January-June), naturally released by the forest metabolism, and fine mode dominated biomass burning aerosols in the dry season (July-December), transported from regional fires. Dry particle median scattering coefficients at the wavelength of 550 nm increased from 6.3 Mm-1 to 22 Mm-1, whereas absorption at 637 nm increased from 0.5 Mm-1 to 2.8 Mm-1 from wet to dry season. Most of the scattering in the dry season was attributed to the predominance of fine mode particles (40-80% of PM10 mass), while the enhanced absorption coefficients are attributed to the presence of light absorbing aerosols from biomass burning. As both scattering and absorption increased in the dry season, the single scattering albedo (SSA) did not show a significant seasonal variability, in average 0.86 ± 0.08 at 637 nm for dry particles. Measured particle optical properties were used to estimate the aerosol forcing efficiency at the top of the atmosphere. Results indicate that in this pristine forest site the radiative balance was dominated by the cloud cover, or, in other words, the aerosol indirect effect predominated over the direct effect, particularly in the wet season. Due to the high cloud fractions, the aerosol forcing efficiency was below -3.5 W m-2 in 70% of the wet season days and in 46% of the dry season days. These values are lower than the ones reported in the literature, which are based on remote sensing data. Besides the seasonal variation, the influence of external aerosol sources was observed occasionally. Periods of influence of the Manaus urban plume were detected

  19. 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

  20. Joint elastic side-scattering LIDAR and Raman LIDAR measurements of aerosol optical properties in south east Colorado

    NASA Astrophysics Data System (ADS)

    Wiencke, L.; Rizi, V.; Will, M.; Allen, C.; Botts, A.; Calhoun, M.; Carande, B.; Claus, J.; Coco, M.; Emmert, L.; Esquibel, S.; Grillo, A. F.; Hamilton, L.; Heid, T. J.; Iarlori, M.; Klages, H.-O.; Kleifges, M.; Knoll, B.; Koop, J.; Mathes, H.-J.; Menshikov, A.; Morgan, S.; Patterson, L.; Petrera, S.; Robinson, S.; Runyan, C.; Sherman, J.; Starbuck, D.; Wakin, M.; Wolf, O.

    2017-03-01

    We describe an experiment, located in south-east Colorado, U.S.A., that measured aerosol optical depth profiles using two LIDAR techniques. Two independent detectors measured scattered light from a vertical UV laser beam. One detector, located at the laser site, measured light via the inelastic Raman backscattering process. This is a common method used in atmospheric science for measuring aerosol optical depth profiles. The other detector, located approximately 40 km distant, viewed the laser beam from the side. This detector featured a 3.5 m2 mirror and measured elastically scattered light in a bistatic LIDAR configuration following the method used at the Pierre Auger cosmic ray observatory. The goal of this experiment was to assess and improve methods to measure atmospheric clarity, specifically aerosol optical depth profiles, for cosmic ray UV fluorescence detectors that use the atmosphere as a giant calorimeter. The experiment collected data from September 2010 to July 2011 under varying conditions of aerosol loading. We describe the instruments and techniques and compare the aerosol optical depth profiles measured by the Raman and bistatic LIDAR detectors.

  1. Effective Henry's Law constant measurements for glyoxal in model aerosols containing sulfate

    NASA Astrophysics Data System (ADS)

    Kampf, C. J.; Waxman, E.; Slowik, J. G.; Dommen, J.; Prevot, A. S.; Noziere, B.; Hoffmann, T.; Volkamer, R.

    2011-12-01

    Traditional models represent secondary organic aerosol (SOA) formation based on the gas-phase oxidation of a limited set of precursor molecules. However, these models tend to under-estimate the amounts and degree of oxygenation of actual SOA, indicating missing processes. One such source that has become increasingly important in recent years is glyoxal (CHOCHO, the smallest alpha-dicarbonyl). Unlike traditional SOA precursors, glyoxal forms SOA by partitioning to the aqueous phase according to Henry's Law. This work presents an analysis of Henry's Law constants for glyoxal uptake to laboratory-generated aerosols in a dynamically coupled gas-aerosol system. We combine CU LED-CE-DOAS measurements of gas-phase glyoxal with online HR-Tof-AMS and time-resolved HPLC ESI MS/MS particle-phase measurements to characterize the time resolved evolution of glyoxal partitioning, and relate molecular-specific measurements to AMS mass spectra. The experiments were performed in the simulation chamber facility at PSI, Switzerland, and investigate ammonium sulfate (AS), and mixed AS / fulvic acid seed aerosols under relative humidity conditions ranging from 50 to 85% RH. The Henry's Law and effective Henry's Law constants are compared with other values reported in the literature.

  2. Effective Henry's Law constant measurements for glyoxal in model aerosols containing sulfate

    NASA Astrophysics Data System (ADS)

    Kampf, C.; Waxman, E.; Slowik, J.; Dommen, J.; Prevot, A.; Baltensperger, U.; Noziere, B.; Hoffmann, T.; Volkamer, R.

    2012-04-01

    Traditional models represent secondary organic aerosol (SOA) formation based on the gas-phase oxidation of a limited set of precursor molecules. However, these models tend to under-estimate the amounts and degree of oxygenation of actual SOA, indicating missing processes. One such source that has become increasingly important in recent years is glyoxal (CHOCHO, the smallest alpha-dicarbonyl). Unlike traditional SOA precursors, glyoxal forms SOA by partitioning to the aqueous phase according to Henry's Law. This work presents an analysis of Henry's Law constants for glyoxal uptake to laboratory-generated aerosols in a dynamically coupled gas-aerosol system. We combine CU LED-CE-DOAS measurements of gas-phase glyoxal with online HR-Tof-AMS and time-resolved HPLC ESI MS/MS particle-phase measurements to characterize the time resolved evolution of glyoxal partitioning, and relate molecular-specific measurements to AMS mass spectra. The experiments were performed in the simulation chamber facility at PSI, Switzerland, and investigate ammonium sulfate (AS), and mixed AS / fulvic acid seed aerosols under relative humidity conditions ranging from 50 to 85% RH. The Henry's Law and effective Henry's Law constants are compared with other values reported in the literature.

  3. Ground-Based Aerosol Measurements | Science Inventory ...

    EPA Pesticide Factsheets

    Atmospheric particulate matter (PM) is a complex chemical mixture of liquid and solid particles suspended in air (Seinfeld and Pandis 2016). Measurements of this complex mixture form the basis of our knowledge regarding particle formation, source-receptor relationships, data to test and verify complex air quality models, and how PM impacts human health, visibility, global warming, and ecological systems (EPA 2009). Historically, PM samples have been collected on filters or other substrates with subsequent chemical analysis in the laboratory and this is still the major approach for routine networks (Chow 2005; Solomon et al. 2014) as well as in research studies. In this approach, air, at a specified flow rate and time period, is typically drawn through an inlet, usually a size selective inlet, and then drawn through filters, 1 INTRODUCTION Atmospheric particulate matter (PM) is a complex chemical mixture of liquid and solid particles suspended in air (Seinfeld and Pandis 2016). Measurements of this complex mixture form the basis of our knowledge regarding particle formation, source-receptor relationships, data to test and verify complex air quality models, and how PM impacts human health, visibility, global warming, and ecological systems (EPA 2009). Historically, PM samples have been collected on filters or other substrates with subsequent chemical analysis in the laboratory and this is still the major approach for routine networks (Chow 2005; Solomo

  4. The East and Southeast Asia Initiatives: Aerosol Column Measurements

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee; Hsu, Christina N.; Li, Zhanqing

    2003-01-01

    Asian Study of Tropospheric Aerosols: an International Regional Experiment) and BASE-ASIA (Biomass-burning Aerosols in South East-Asia: Smoke Impact Assessment) will be presented and discussed their contribution to better understand the impacts of aerosols on regional-to- global climate, hydrological and carbon cycles, and tropospheric chemistry.

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

    PubMed

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

    2008-12-15

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

  6. 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

  7. The Microphysical and Chemical properties of aerosol particles from the United Arab Emirates Unified Aerosol Experiment (UAE2) and from the Bodele-BODEX Experiment

    NASA Astrophysics Data System (ADS)

    Martins, J.; Chaudhry, Z.; Todd, M.; Kaufman, Y.; Artaxo, P.

    2005-12-01

    Aerosol filters collected during the UAE2 experiment (August 2004), and during the BODEX experiment (in the Bodele region, February 2005) were analyzed for spectral absorption properties (from 350-2500nm), mass concentration (fine and coarse modes), electron microscopy, and chemical composition. The UAE2 samples show evidence of absorption by dust and urban pollution particles. In the fine mode, the urban pollution particles show spectral dependence inversely proportional to the wavelength, which is compatible with small black carbon aerosols. The coarse mode shows evidences of the internal mixture between dust and pollution, producing the typical strong absorption in UV-Visible wavelengths produced by dust, as well as significant absorption in the NIR (near infrared) coming from the dust-pollution combination. On the other hand, the Bodele samples show at least two types of dust absorption behavior: 1 - very strong absorption efficiency in the UV and visible wavelengths with nearly no absorption in the NIR; 2 - very strong absorption efficiency in the UV-VIS region with significant absorption in the NIR. Additional samples collected in the Amazon region, in Brazil, show evidence of long-range transport of dust from the Sahara. The chemical composition and microphysical properties of the Amazon Samples are compared with those measured in the UAE and Bodele regions. The chemical composition of these samples provides additional insight on previous theories of the fertilization of the Amazon by long-range transport of dust from the Sahara region.

  8. 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.

  9. Source attribution of climatically important aerosol properties measured at Paposo (Chile) during VOCALS

    NASA Astrophysics Data System (ADS)

    Chand, D.; Hegg, D. A.; Wood, R.; Shaw, G. E.; Wallace, D.; Covert, D. S.

    2010-11-01

    Measurements of submicron aerosol composition, light scattering, and size distribution were made from 17 October to 15 November 2008 at the elevated Paposo site (25° 0.4' S, 70° 27.01' W, 690 m a.s.l.) on the Chilean coast as part of the VOCALS* Regional Experiment (REx). Based on the chemical composition measurements, a receptor modeling analysis using Positive Matrix Factorization (PMF) was carried out, yielding four broad source categories of the aerosol mass, light scattering coefficient, and a proxy for cloud condensation nucleus (CCN) concentration at 0.4% supersaturation derived from the size distribution measurements assuming an observed soluble mass fraction of 0.53. The sources resolved were biomass burning, marine, an urban-biofuels mix and a somewhat ambiguous mix of smelter emissions and mineral dust. The urban-biofuels mix is the most dominant aerosol mass component (52%) followed by biomass burning (25%), smelter/soil dust (12%) and marine (9%) sources. The average (mean±std) submicron aerosol mass concentration, aerosol light scattering coefficient and proxy CCN concentration were, 8.77±5.40 μg m-3, 21.9±11.0 Mm-1 and 548±210 cm-3, respectively. Sulfate is the dominant identified submicron species constituting roughly 40% of the dry mass (3.64±2.30 μg m-3), although the indentified soluble species constitute only 53% of the mass. Much of the unidentified mass is likely organic in nature. The relative importance of each aerosol source category is different depending upon whether mass, light scattering, or CCN concentration is being considered, indicating that the mean size of aerosols associated with each source are different. Marine aerosols do not appear to contribute to more than 10% to either mass, light scattering, or CCN concentration at this site. Back trajectory cluster analysis proved consistent with the PMF source attribution. *VOCALS: VAMOS** Ocean-Cloud-Atmosphere-Land Study (VOCALS) **VAMOS: Variability of American Monsoon

  10. Source attribution of climatically important aerosol properties measured at Paposo (Chile) during VOCALS

    NASA Astrophysics Data System (ADS)

    Chand, D.; Hegg, D. A.; Wood, R.; Shaw, G. E.; Wallace, D.; Covert, D. S.

    2010-07-01

    Measurements of submicron aerosol composition, light scattering, and size distribution were made from 17 October to 15 November 2008 at the elevated Paposo site (25° 0.4' S, 70°27.01' W, 690 m a.s.l.) on the Chilean coast as part of the VOCALS1 Regional Experiment (REx). Based on the chemical composition measurements, a receptor modeling analysis using Positive Matrix Factorization (PMF) was carried out, yielding four broad source categories of the aerosol mass, light scattering coefficient, and a proxy for cloud condensation nucleus (CCN) concentration at 0.4% supersaturation derived from the size distribution measurements assuming an observed soluble mass fraction of 0.53. The sources resolved were biomass burning, marine, an urban-biofuels mix and a somewhat ambiguous mix of smelter emissions and mineral dust. The urban-biofuels mix is the most dominant aerosol mass component (52%) followed by biomass burning (25%), smelter/soil dust (12%) and marine (9%) sources. The average (mean±std) submicron aerosol mass concentration, aerosol light scattering coefficient and proxy CCN concentration were, 8.77±5.40 μg m-3, 21.9±11.0 Mm-1 and 548±210 cm-3, respectively. Sulfate is the dominant identified submicron species constituting roughly 40% of the dry mass (3.64±2.30 μg m-3, although the indentified soluble species constitute only 53% of the mass. Much of the unidentified mass is likely organic in nature. The relative importance of each aerosol source category is different depending upon whether mass, light scattering, or CCN concentration is being considered, indicating that the mean size of aerosols associated with each source are different. Marine aerosols do not appear to contribute to more than 10% to either mass, light scattering, or CCN concentration at this site. Back trajectory cluster analysis proved consistent with the PMF source attribution. 1 VOCALS: VAMOS Ocean-Cloud-Atmosphere-Land Study (VOCALS)VAMOS: Variability of American Monsoon System

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

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Bergstrom, Robert W.; Schmid, B.; Livingston, J. M.

    2000-01-01

    We estimate the impact of North Atlantic aerosols on the net short-wave flux at the tropopause by combining satellite-derived aerosol optical depth (AOD) maps with model aerosol properties determined via closure analyses in TARFOX and ACE 2. We exclude African dust, primarily by restricting latitudes to 25-60 N. The analyses use in situ aerosol composition measurements and air- and ship-borne sun-photometer measurements of AOD spectra. The aerosol model yields computed flux sensitivities (dFlux/dAOD) that agree with measurements by airborne flux radiometers in TARFOX. Its midvisible single-scattering albedo is 0.9. which is in the range obtained from in situ measurements of scattering and absorption in both TARFOX and ACE 2. Combining satellite-derived AOD maps with the aerosol model yields maps of 24-hour average net radiative flux changes. For simultaneous AVHRR, radiance measurements exceeded the sunphotometer AODs by about 0.04. However. shipboard sunphotometer and AVHRR AODs agreed Within 0.02 for data acquired during satellite overflights on two other days. We discuss attempts to demonstrate column closure within the MBL by comparing shipboard sunphotometer AODs and values calculated from simultaneous shipboard in-situ aerosol size distribution measurements. These comparisons were mostly unsuccessful, but they illustrate the difficulties inherent in this type of closure analysis. Specifically, AODs derived from near-surface in-situ size distribution measurements are extremely sensitive to the assumed hygroscopic growth model that itself requires an assumption of particle composition as a function of height and size, to the radiosonde-measured relative humidity, and to the vertical profile of particle number. We investigate further the effects of hygroscopic particle growth within the MBL by using shipboard lidar aerosol backscatter profiles together with the sunphotometer AOD.

  12. First lidar measurements of water vapor and aerosols from a high-altitude aircraft

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Ismail, Syed

    1995-01-01

    Water vapor plays an important role in many atmospheric processes related to radiation, climate change, atmospheric dynamics, meteorology, the global hydrologic cycle, and atmospheric chemistry, and yet our knowledge of the global distribution of water vapor is very limited. The differential absorption lidar (DIAL) technique has the potential of providing needed high resolution water vapor measurements from aircraft and from space, and the Lidar Atmospheric Sensing Experiment (LASE) is a key step in the development of this capability. The LASE instrument is the first fully engineered, autonomous DIAL system, and it is designed to operate from a high-altitude aircraft (ER-2) and to make water vapor and aerosol profile measurements across the troposphere. The LASE system was flown from the NASA Wallops Flight Facility in a series of engineering flights during September 1994. This paper discusses the characteristics of the LASE system and presents the first LASE measurements of water vapor and aerosol profiles.

  13. Comparisons of Remote Sensing Retrievals and in situ Measurements of Aerosol Fine Mode Fraction during ACE-Asia

    NASA Technical Reports Server (NTRS)

    Gasso, Santiago; O'Neill, Norm

    2006-01-01

    We present sunphotometer-retrieved and in situ fine mode fractions (FMF) measured onboard the same aircraft during the ACE-Asia experiment. Comparisons indicate that the latter can be used to identify whether the aerosol under observation is dominated by a mixture of modes or a single mode. Differences between retrieved and in situ FMF range from 5-20%. When profiles contained multiple layers of aerosols, the retrieved and measured FMF were segregated by layers. The comparison of layered and total FMF from the same profile indicates that columnar values are intermediate to those derived from layers. As a result, a remotely sensed FMF cannot be used to distinguish whether the aerosol under observation is composed of layers each with distinctive modal features or all layers with the same modal features. Thus, the use of FMF in multiple layer environments does not provide unique information on the aerosol under observation.

  14. Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx

    SciTech Connect

    Kleinman L. I.; Daum, P. H.; Lee, Y.-N.; Lewis, E. R.; Sedlacek III, A. J.; Senum, G. I.; Springston, S. R.; Wang, J.; Hubbe, J.; Jayne, J.; Min, Q.; Yum, S. S.; Allen, G.

    2012-01-04

    During the VOCALS Regional Experiment, the DOE G-1 aircraft was used to sample a varying aerosol environment pertinent to properties of stratocumulus clouds over a longitude band extending 800 km west from the Chilean coast at Arica. Trace gas and aerosol measurements are presented as a function of longitude, altitude, and dew point in this study. Spatial distributions are consistent with an upper atmospheric source for O{sub 3} and South American coastal sources for marine boundary layer (MBL) CO and aerosol, most of which is acidic sulfate. Pollutant layers in the free troposphere (FT) can be a result of emissions to the north in Peru or long range transport from the west. At a given altitude in the FT (up to 3 km), dew point varies by 40 C with dry air descending from the upper atmospheric and moist air having a boundary layer (BL) contribution. Ascent of BL air to a cold high altitude results in the condensation and precipitation removal of all but a few percent of BL water along with aerosol that served as CCN. Thus, aerosol volume decreases with dew point in the FT. Aerosol size spectra have a bimodal structure in the MBL and an intermediate diameter unimodal distribution in the FT. Comparing cloud droplet number concentration (CDNC) and pre-cloud aerosol (D{sub p} > 100 nm) gives a linear relation up to a number concentration of {approx}150 cm{sup -3}, followed by a less than proportional increase in CDNC at higher aerosol number concentration. A number balance between below cloud aerosol and cloud droplets indicates that {approx}25 % of aerosol with D{sub p} > 100 nm are interstitial (not activated). A direct comparison of pre-cloud and in-cloud aerosol yields a higher estimate. Artifacts in the measurement of interstitial aerosol due to droplet shatter and evaporation are discussed. Within each of 102 constant altitude cloud transects, CDNC and interstitial aerosol were anti-correlated. An examination of one cloud as a case study shows that the

  15. Extending the performances of stratospheric aerosol characterization in the 2002-2011 period through data merging of GOMOS and OSIRIS measurements

    NASA Astrophysics Data System (ADS)

    Bingen, Christine; Robert, Charles; Vanhellemont, Filip; Mateshvili, Nina; Dekemper, Emmanuel; Fussen, Didier; Bourassa, Adam

    2016-04-01

    Stratospheric extinction and size information are two important aerosol parameters used to model the role of stratospheric aerosols in the atmospheric system, and to assess the respective importance of volcanic and anthropogenic aerosols. Since the historical aerosol minimum in 1998-2000, several remote sensing experiments have provided radiative aerosol measurements, using various and often challenging measurement principles, and, for each of them, a specific set of spectral channels. This results in a rich patchwork of spectral information presenting gaps and discontinuities in space, time, and wavelength. Acquiring aerosol size information on a global scale is a very challenging task. Such information can be retrieved by radial inversion of the extinction spectrum, but this task is often a struggle due to the reduced number of spectral channels and mainly to a limitation of the spectral range. Combining aerosol radiative measurements from multiple remote experiments seems to be a promising way to provide modellers with an improved characterization of the aerosol extinction and size information they need. This work presents the current status of the development of merged aerosol datasets from the GOMOS and OSIRIS experiments. After presenting the methodology used for the data merging, we will present the latest results obtained in this study and show how the performances of the merged dataset can improve with respect to the ones of each of the individual retrievals.

  16. 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.

  17. LASE Measurements of Water Vapor, Aerosol, and Cloud Distributions in Saharan Air Layers and Tropical Disturbances

    NASA Technical Reports Server (NTRS)

    Ismail, Syed; Ferrare, Richard; Browell, Edward; Kooi, Susan; Notari, Anthony; Butler, Carolyn; Burton, Sharon; Fenn, Marta; Krishnamurti, T. N.; Dunion, Jason; Heymsfield, Gerry; Anderson, Bruce

    2008-01-01

    LASE (Lidar Atmospheric Sensing Experiment) onboard the NASA DC-8 was used to measure high resolution profiles of water vapor and aerosols, and cloud distributions in 14 flights over the eastern Atlantic region during the NAMMA (NASA African Monsoon Multidisciplinary Analyses) field experiment, which was conducted from August 15 to September 12, 2006. These measurements were made in conjunction with flights designed to study African Easterly Waves (AEW), Tropical Disturbances (TD), and Saharan Aerosol Layers (SALs) as well as flights performed in clear air and convective regions. As a consequence of their unique radiative properties and dynamics, SAL layers have a significant influence in the development of organized convection associated with TD. Interactions of the SAL with tropical air during early stages of the development of TD were observed. These LASE measurements represent the first simultaneous water vapor and aerosol lidar measurements to study the SAL and its impact on TDs and hurricanes. Seven AEWs were studied and four of these evolved into tropical storms and three did not. Three out of the four tropical storms evolved into hurricanes.

  18. 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.

  19. 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.

  20. 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.

  1. Aerosol optical properties from multiwavelength lidar measurements in Romania

    NASA Astrophysics Data System (ADS)

    Nicolae, Doina; Talianu, Camelia; Carstea, Emil; Nemuc, Anca

    2009-09-01

    Vertically resolved profiles of optical properties of aerosols were measured using a multi-wavelength lidar system-RALI, set up at the scientific research center in Magurele, Bucharest area (44.35 N latitude, 26.03 E longitude) during 2008. The use of multiple laser wavelengths has enabled us to observe significant variations in backscatter profiles depending on the particle origins. An air mass backward trajectory analysis, using Hysplit-4, was carried out to track the aerosol plumes. Aerosols can serve as valuable tracers of air motion in the planetary boundary layer (PBL). The height of layers in the lower troposphere from lidar signal was calculated using the gradient method- minima of the first derivative. The Richardson number method was used to estimate PBL height from the radio-soundings. We have used pressure, temperature and dew point profiles as well as the wind direction profiles from NOAA (National Oceanic and Atmospheric Administration) data base. The results were consistent with the ones obtained from LIDAR.

  2. Spectral Measurements of Aerosol Absorption from UV to VISIBLE

    NASA Astrophysics Data System (ADS)

    Krotkov, N. A.; Labow, G.; Herman, J.; Bhartia, P. K.; Slusser, J.; Durham, B.; Janson, G.; Wilson, C.; Disterhoft, P.; Cede, A.; Abuhassan, N.; Eck, T. F.; Holben, B.; Bais, A.; Rapsomanikis, S.

    2007-05-01

    Amount of solar radiation reaching the Earth's surface can be strongly influenced by aerosol absorption. The aerosol absorption optical thickness (AAOT) in the visible and near IR (440 nm- 1020nm) is routinely produced from almucantar measurements made by the CIMEL instruments in the AERONET network. AAOT in the UV (300nm- 368nm) have been derived from the total and diffuse hemispherical flux measurements made by UV- Multifilter Rotating Shadowband Radiometer (UV-MFRSR, Yankee Environmental Systems, Inc.) instruments. However, no direct comparisons between these two methods exist because the CIMEL wavelengths (used in almucantar retrievals) do not overlap with the UV-MFRSR wavelengths. To enable direct comparisons between the two techniques, we have modified our UV-MFRSR, part of USDA UVB Monitoring and Research Network, by replacing standard 300nm filter with 440nm filter used in AERONET network. The instrument has been deployed at Mauna Loa Observatory, at NASA GSFC in Greenbelt, MD (July 2005 - June 2006) and during SCOUT-03 field campaign in Thessaloniki, Greece in July 2006. During these deployments the instrument's calibration was monitored daily using co-located AERONET and BREWER direct sun measurements of aerosol extinction optical thickness (AOT). Between the deployments the instrument was thoroughly calibrated at the NOAA Central UV Calibration Facility in Boulder, Colorado. We find that the UV-MSFRSR instrument is highly susceptible to calibration drifts. However, these drifts can be accurately assessed using AERONET and BREWER direct sun data. After correcting for these calibration changes, the AAOT was inferred by fitting the measurements of global and diffuse atmospheric transmittances with the forward RT model independently at each spectral channel. The AOT data and ancillary measurements of aerosol column particle size distribution and refractive index in the visible wavelengths (by CIMEL sun-sky almucantar inversions), direct -sun column NO2 and

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  4. Comparison of LIDAR and Cavity Ring-Down Measurements of Aerosol Extinction and Study of Inferred Aerosol Gradients

    NASA Astrophysics Data System (ADS)

    Eberhard, W. L.; Massoli, P.; McCarty, B. J.; Machol, J. L.; Tucker, S. C.

    2007-12-01

    A LIDAR and a Cavity Ring-Down Aerosol Extinction Spectrometer (CRD) instrument simultaneously measured aerosol extinction at 355-nm wavelength from aboard the Research Vessel Ronald H. Brown during the Texas Air Quality Study II campaign. The CRD measured air sampled from the top of the common mast used by several in situ aerosol optical and chemical instruments. The LIDAR's scan sequence included near-horizontal stares (2° elevation angle) with pointing corrected for ship's roll. Aerosol extinction was retrieved using a variant of the slope method. The LIDAR therefore sampled air over a short vertical extent with midpoint higher above the surface than the CRD intake and at a horizontal distance of as much as a few kilometers. The CRD measured aerosol extinction at dry and at high (near-ambient) relative humidity (RH) levels, which were used to scale the measurements to ambient RH for the comparisons. Data from the two instruments for well-mixed conditions (supported by turbulence and atmospheric stability data) are compared to evaluate the degree of agreement between the two methods and reasons for differences. For instances of larger differences, the aerosol gradient below approximately 100 m altitude is inferred and examined in context of low-level meteorological parameters and LIDAR measurements at higher angles.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  6. In-Situ Measurements of Aerosols from Motor Vehicles in the Caldecott Tunnel

    NASA Astrophysics Data System (ADS)

    Hallar, A. G.; Strawa, A.; Kirchstetter, T. W.; Bokarius, K.; Harley, R.

    2005-12-01

    A study was recently conducted in the Caldecott Tunnel, a heavily-used tunnel located east of San Francisco, CA. The aerosol sampled in this study was characterized by fresh automobile and diesel exhaust. Roadway tunnel studies have some strong advantages over traditional dynamometer studies. For instance this study captured the aggregate emissions of a fleet of vehicles (4000 cars/hr in the center bore) operating under real-world, in-use conditions. This experiment involved two separate test-beds, one week of measurements within a light duty (gasoline) vehicle bore and one week within a mixed light duty (gasoline cars)/ heavy duty (diesel trucks) vehicle bore. Furthermore, within the framework of this study, the relative humidity was adjusted within the sample line to test the possible hydroscopic nature of the emissions. In the heavy duty bore, an increase of RH ( from 45 percent to 80 percent) did not have an observable effect on the aerosol optical properties. A new cavity ring-down (CRD) instrument, called Cadenza (NASA-ARC), measures the aerosol extinction coefficient for 675 nm and 1550 nm light, and simultaneously measures the scattering coefficient at 675 nm. The absorption coefficient is obtained from the difference of measured extinction and scattering within the instrument. Measurements from Cadenza, a standard aethalometer, and a Scanning Mobility Particle Sizer (SMPS, TSI Inc.) are presented. The aethalometer is a filter-based photometer and the near infrared channel is calibrated to produce a measure of BC mass loading. The SMPS system measures submicrometer aerosols in the range from 3 to 1000 nm in diameter. It employs an electrostatic classifier to determine the particle size, and a Condensation Particle Counter (CPC) to determine particle concentration. A majority of particles, approximately 90 percent, measured were "ultra-fine" with sizes below 100 nm.

  7. Precipitation changes due to anthropogenic aerosols and greenhouse gases in MLO experiments

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    We analyze mixed layer ocean (MLO) equilibria from time slice experiments with the global climate model ECHAM6.1, combined with the Hamburg aerosol module HAM2.2. For each first year of each decade from 1870 to 2000, three MLO experiments were carried out: aerosols and greenhouse gases (GHGs) of that year, only aerosols of that year and GHGs of 1850, only GHGs of that year and aerosols of 1850. We quantify how total precipitation as well as its composites (convective and large scale) change through these experiments on global and regional scales. Special emphasis is given to differences in precipitation response to either aerosol or GHG forcing, despite similar (absolute value) global mean temperature response. Finally, we address the role of the prescribed deep ocean heat flux.

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

    SciTech Connect

    Leifer, R.; Knuth, R.H.; Guggenheim, S.F.; Albert, B.

    1996-04-01

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

  9. Using Raman-lidar-based regularized microphysical retrievals and Aerosol Mass Spectrometer measurements for the characterization of biomass burning aerosols

    NASA Astrophysics Data System (ADS)

    Samaras, Stefanos; Nicolae, Doina; Böckmann, Christine; Vasilescu, Jeni; Binietoglou, Ioannis; Labzovskii, Lev; Toanca, Florica; Papayannis, Alexandros

    2015-10-01

    In this work we extract the microphysical properties of aerosols for a collection of measurement cases with low volume depolarization ratio originating from fire sources captured by the Raman lidar located at the National Institute of Optoelectronics (INOE) in Bucharest. Our algorithm was tested not only for pure smoke but also for mixed smoke and urban aerosols of variable age and growth. Applying a sensitivity analysis on initial parameter settings of our retrieval code was proved vital for producing semi-automatized retrievals with a hybrid regularization method developed at the Institute of Mathematics of Potsdam University. A direct quantitative comparison of the retrieved microphysical properties with measurements from a Compact Time of Flight Aerosol Mass Spectrometer (CToF-AMS) is used to validate our algorithm. Microphysical retrievals performed with sun photometer data are also used to explore our results. Focusing on the fine mode we observed remarkable similarities between the retrieved size distribution and the one measured by the AMS. More complicated atmospheric structures and the factor of absorption appear to depend more on particle radius being subject to variation. A good correlation was found between the aerosol effective radius and particle age, using the ratio of lidar ratios (LR: aerosol extinction to backscatter ratios) as an indicator for the latter. Finally, the dependence on relative humidity of aerosol effective radii measured on the ground and within the layers aloft show similar patterns.

  10. Polar stratospheric cloud sightings by SAM II. [Stratospheric Aerosol Measurement onboard Nimbus 7

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Chu, W. P.; Steele, H. M.; Hamill, P.; Swissler, T. J.

    1982-01-01

    The functions and data gained regarding stratospheric cloud sightings by the stratospheric aerosol measurement (SAM) II experiment on board the Numbus 7 spacecraft are reported. SAM II comprises a single channel sun photometer centered at 1.0 micron wavelength for measuring the solar intensity when the sun descends below an apparent 300 km altitude until the sun is occulted by clouds or the horizon. Readings are also made during sunrise in an opposite fashion. Transmission profiles are developed from the data and used to construct profiles of aerosol extinction with a 1 km resolution. Polar stratospheric clouds have been observed in more than 90% of the cases when the minimum temperature is 185 K or less, and 45% of the time when the temperature is 193 K or less. The clouds were more prevalent in the Antarctic winter than during the Arctic winter, and cloud height was lower than indicated by previous data.

  11. Arctic aerosol and cloud measurements performed during IAOOS 2014

    NASA Astrophysics Data System (ADS)

    Mariage, Vincent; Pelon, Jacques; Blouzon, Frédéric; Geyskens, Nicolas; Amarouche, Nadir; Drezen, Christine; Calzas, Michel; Victori, Stéphane; Garracio, Magali; Desautez, Alain; Pascal, Nicolas; Foujols, Thomas; Sarkissian, Alain; Pommereau, Jean-Pierre; Sennechael, Nathalie; Provost, Christine

    2015-04-01

    Better understanding of atmosphere-ice-ocean interactions and in particular of the role of aerosols and clouds in this Earth system is of prime importance in the Arctic. In the frame of the French IAOOS Equipex project, a new observational network is planned to be developed for ocean-ice-atmosphere climate survey over the Arctic, starting in 2015, to complement satellite observations. Eye-safe lidar measurements will allow us to profile aerosols and clouds for the atmospheric part, with the objective to perform regular measurements and characterize the vertical structure and optical properties. Radiation and meteorological parameters will be measured at the surface. A first buoy has been prototyped and deployed in April 2014 at the Barneo site set by the Russian teams at the North Pole. Measurements with the first autonomous backscatter lidar ever deployed in the arctic have been taken from April to end of November 2014 before the buoy was lost. Four profiles a day have been performed allowing a good sampling of cloud variability. Observations have shown that the occurrence of low level clouds was higher than 90% during summer. The project is presented, instrument performance is described and first results are discussed.

  12. MPL-Net Measurements of Aerosol and Cloud Vertical Distributions at Co-Located AERONET Sites

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; Campbell, James R.; Berkoff, Timothy A.; Spinhirne, James D.; Tsay, Si-Chee; Holben, Brent; Starr, David OC. (Technical Monitor)

    2002-01-01

    In the early 1990s, the first small, eye-safe, and autonomous lidar system was developed, the Micropulse Lidar (MPL). The MPL acquires signal profiles of backscattered laser light from aerosols and clouds. The signals are analyzed to yield multiple layer heights, optical depths of each layer, average extinction-to-backscatter ratios for each layer, and profiles of extinction in each layer. In 2000, several MPL sites were organized into a coordinated network, called MPL-Net, by the Cloud and Aerosol Lidar Group at NASA Goddard Space Flight Center (GSFC) using funding provided by the NASA Earth Observing System. tn addition to the funding provided by NASA EOS, the NASA CERES Ground Validation Group supplied four MPL systems to the project, and the NASA TOMS group contributed their MPL for work at GSFC. The Atmospheric Radiation Measurement Program (ARM) also agreed to make their data available to the MPL-Net project for processing. In addition to the initial NASA and ARM operated sites, several other independent research groups have also expressed interest in joining the network using their own instruments. Finally, a limited amount of EOS funding was set aside to participate in various field experiments each year. The NASA Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) project also provides funds to deploy their MPL during ocean research cruises. All together, the MPL-Net project has participated in four major field experiments since 2000. Most MPL-Net sites and field experiment locations are also co-located with sunphotometers in the NASA Aerosol Robotic Network. (AERONET). Therefore, at these locations data is collected on both aerosol and cloud vertical structure as well as column optical depth and sky radiance. Real-time data products are now available from most MPL-Net sites. Our real-time products are generated at times of AERONET aerosol optical depth (AOD) measurements. The AERONET AOD is used as input to our

  13. In Situ Aerosol Profile Measurements and Comparisons with SAGE 3 Aerosol Extinction and Surface Area Profiles at 68 deg North

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Under funding from this proposal three in situ profile measurements of stratospheric sulfate aerosol and ozone were completed from balloon-borne platforms. The measured quantities are aerosol size resolved number concentration and ozone. The one derived product is aerosol size distribution, from which aerosol moments, such as surface area, volume, and extinction can be calculated for comparison with SAGE III measurements and SAGE III derived products, such as surface area. The analysis of these profiles and comparison with SAGE III extinction measurements and SAGE III derived surface areas are provided in Yongxiao (2005), which comprised the research thesis component of Mr. Jian Yongxiao's M.S. degree in Atmospheric Science at the University of Wyoming. In addition analysis continues on using principal component analysis (PCA) to derive aerosol surface area from the 9 wavelength extinction measurements available from SAGE III. Ths paper will present PCA components to calculate surface area from SAGE III measurements and compare these derived surface areas with those available directly from in situ size distribution measurements, as well as surface areas which would be derived from PCA and Thomason's algorithm applied to the four wavelength SAGE II extinction measurements.

  14. Retrieval of aerosol composition using ground-based remote sensing measurements

    NASA Astrophysics Data System (ADS)

    Xie, Yisong; Li, Zhengqiang; Zhang, Ying; Li, Donghui; Li, Kaitao

    2016-04-01

    The chemical composition and mixing states of ambient aerosol are the main factors deciding aerosol microphysical and optical properties, and thus have significant impacts on regional or global climate change and air quality. Traditional approaches to detect atmospheric aerosol composition include sampling with laboratory analysis and in-situ measurements. They can accurately acquire aerosol components, however, the sampling or air exhausting could change the status of ambient aerosol or lead to some mass loss. Additionally, aerosol is usually sampled at the surface level so that it is difficult to detect the columnar aerosol properties. Remote sensing technology, however, can overcome these problems because it is able to detect aerosol information of entire atmosphere by optical and microphysical properties without destructing the natural status of ambient aerosol. This paper introduces a method to acquire aerosol composition by the remote sensing measurements of CIMEL CE318 ground-based sun-sky radiometer. A six component aerosol model is used in this study, including one strong absorbing component Black Carbon (BC), two partly absorbing components Brown Carbon (BrC) and Mineral Dust (MD), two scattering components Ammonia Sulfate-like (AS) and Sea Salt (SS), and Aerosol Water uptake (AW). Sensitivity analysis are performed to find the most sensitive parameters to each component and retrieval method for each component is accordingly developed. Different mixing models such as Maxwell-Garnett (MG), Bruggeman (BR) and Volume Average (VA) are also studied. The residual minimization method is used by comparing remote sensing measurements and simulation outputs to find the optimization of aerosol composition (including volume fraction and mass concentration of each component). This method is applied to measurements obtained from Beijing site under different weather conditions, including polluted haze, dust storm and clean days, to investigate the impacts of mixing

  15. Retrieval of aerosol composition using ground-based remote sensing measurements

    NASA Astrophysics Data System (ADS)

    Xie, Y.; Li, Z.; Xu, H.; Chen, X.; Li, K.; Lv, Y.; Li, D.; Zhang, Y.

    2015-12-01

    The chemical composition and mixing status of ambient aerosol are the main factors deciding aerosol microphysical and optical properties, and thus have significant impacts on regional or global climate change and air quality. Traditional approaches to detect atmospheric aerosol composition include sampling with laboratory analysis and in-situ measurement. They can accurately acquire aerosol components, however, the sampling or air exhausting could change the status of aerosol or have some mass loss. Additionally, aerosol is usually sampled at the surface level so that it is difficult to detect the columnar aerosol properties. Remote sensing technology, however, can overcome these problems because it investigate aerosol information by optical and microphysical properties without destructing the natural status of ambient aerosol. This paper introduce a method to acquire aerosol composition by the remote sensing measurements of CIMEL CE318 ground-based sun-sky radiometer. A six component aerosol model is used in this study, including one strong absorbing component Black Carbon (BC), two partly absorbing components Brown Carbon (BrC) and Mineral Dust (MD), two scattering components Ammonia Sulfate-like (AS) and Sea Salt (SS), and Aerosol Water uptake (AW). Sensitivity analysis are performed to find the most sensitive parameters to each component and retrieval method for each component is accordingly developed. The residual minimization method is used by comparing remote sensing measurements and simulation outputs to find the optimization of aerosol composition (including volume fraction and mass concentration of each component). This method is applied to real measurements obtained from Beijing site under different weather conditions, including polluted haze, dust storm and clean days, to investigate the impacts of mixing states of aerosol particles on aerosol composition retrieval.

  16. 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.

  17. Retrievals of Profiles of Fine And Coarse Aerosols Using Lidar And Radiometric Space Measurements

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram; Tanre, Didier; Leon, Jean-Francois; Pelon, Jacques; Lau, William K. M. (Technical Monitor)

    2002-01-01

    In couple of years we expect the launch of the CALIPSO lidar spaceborne mission designed to observe aerosols and clouds. CALIPSO will collect profiles of the lidar attenuated backscattering coefficients in two spectral wavelengths (0.53 and 1.06 microns). Observations are provided along the track of the satellite around the globe from pole to pole. The attenuated backscattering coefficients are sensitive to the vertical distribution of aerosol particles, their shape and size. However the information is insufficient to be mapped into unique aerosol physical properties and vertical distribution. Infinite number of physical solutions can reconstruct the same two wavelength backscattered profile measured from space. CALIPSO will fly in formation with the Aqua satellite and the MODIS spectro-radiometer on board. Spectral radiances measured by MODIS in six channels between 0.55 and 2.13 microns simultaneously with the CALIPSO observations can constrain the solutions and resolve this ambiguity, albeit under some assumptions. In this paper we describe the inversion method and apply it to aircraft lidar and MODIS data collected over a dust storm off the coast of West Africa during the SHADE experiment. It is shown that the product of the single scattering albedo, omega, and the phase function, P, for backscattering can be retrieved from the synergism between measurements avoiding a priori hypotheses required for inverting lidar measurements alone. The resultant value of (omega)P(180 deg.) = 0.016/sr are significantly different from what is expected using Mie theory, but are in good agreement with recent results obtained from lidar observations of dust episodes. The inversion is robust in the presence of noise of 10% and 20% in the lidar signal in the 0.53 and 1.06 pm channels respectively. Calibration errors of the lidar of 5 to 10% can cause an error in optical thickness of 20 to 40% respectively in the tested cases. The lidar calibration errors cause degradation in the

  18. Direct aerosol chemical composition measurements to evaluate the physicochemical differences between controlled sea spray aerosol generation schemes

    NASA Astrophysics Data System (ADS)

    Collins, D. B.; Zhao, D. F.; Ruppel, M. J.; Laskina, O.; Grandquist, J. R.; Modini, R. L.; Stokes, M. D.; Russell, L. M.; Bertram, T. H.; Grassian, V. H.; Deane, G. B.; Prather, K. A.

    2014-07-01

    Controlled laboratory studies of the physical and chemical properties of sea spray aerosol (SSA) must be underpinned by a physically and chemically accurate representation of the bubble mediated production of nascent SSA particles. Since bubble bursting is sensitive to the physicochemical properties of seawater, any important differences in the SSA production mechanism are projected into SSA composition. Using direct chemical measurements of SSA at the single-particle level, this study presents an inter-comparison of three laboratory-based, bubble-mediated SSA production schemes: gas forced through submerged sintered glass filters ("frits"), a pulsed plunging waterfall apparatus, and breaking waves in a wave channel filled with natural seawater. The size-resolved chemical composition of SSA particles produced by breaking waves is more similar to particles produced by the plunging waterfall than sintered glass filters. Aerosol generated by disintegrating foam produced by sintered glass filters contained a larger fraction of organic enriched particles and a different size-resolved elemental composition, especially in the 0.8-2 μm size range. These particles, when dried, had more spherical morphologies compared to the more cubic structure expected for pure NaCl particles, which can be attributed to the presence of additional organic carbon. In addition to an inter-comparison of three SSA production methods, the role of the episodic or "pulsed" nature of the waterfall method utilized in this study on SSA composition was undertaken. In organic-enriched seawater, the continuous operation of the plunging waterfall mechanism resulted in the accumulation of surface foam and an over-expression of organic matter in SSA particles compared to pulsed plunging waterfall. Throughout this set of experiments, comparative differences in the SSA number size distribution were coincident with differences in aerosol composition, indicating that the production mechanism of SSA exerts

  19. In situ measurements of organics, meteoritic material, mercury, and other elements in aerosols at 5 to 19 kilometers

    PubMed

    Murphy; Thomson; Mahoney

    1998-11-27

    In situ measurements of the chemical composition of individual aerosol particles at altitudes between 5 and 19 kilometers reveal that upper tropospheric aerosols often contained more organic material than sulfate. Although stratospheric aerosols primarily consisted of sulfuric acid and water, many also contained meteoritic material. Just above the tropopause, small amounts of mercury were found in over half of the aerosol particles that were analyzed. Overall, there was tremendous variety in aerosol composition. One measure of this diversity is that at least 45 elements were detected in aerosol particles. These results have wide implications for the complexity of aerosol sources and chemistry. They also offer possibilities for understanding the transport of atmospheric aerosols.

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

    NASA Astrophysics Data System (ADS)

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

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

  1. The effect of phase partitioning of semivolatile compounds on the measured CCN activity of aerosol particles

    NASA Astrophysics Data System (ADS)

    Romakkaniemi, S.; Jaatinen, A.; Laaksonen, A.; Nenes, A.; Raatikainen, T.

    2013-09-01

    The effect of inorganic semivolatile aerosol compounds on the CCN activity of aerosol particles was studied by using a computational model for a DMT-CCN counter, a cloud parcel model for condensation kinetics and experiments to quantify the modelled results. Concentrations of water vapour and semivolatiles as well as aerosol trajectories in the CCN column were calculated by a computational fluid dynamics model. These trajectories and vapour concentrations were then used as an input for the cloud parcel model to simulate mass transfer kinetics of water and semivolatiles between aerosol particles and the gas phase. Two different questions were studied: (1) how big fraction of semivolatiles is evaporated from particles before activation in the CCN counter? (2) How much the CCN activity can be increased due to condensation of semivolatiles prior to the maximum water supersaturation in the case of high semivolatile concentration in the gas phase? The results show that, to increase the CCN activity of aerosol particles, a very high gas phase concentration (as compared to typical ambient conditions) is needed. We used nitric acid as a test compound. A concentration of several ppb or higher is needed for measurable effect. In the case of particle evaporation, we used ammonium nitrate as a test compound and found that it partially evaporates before maximum supersaturation is reached in the CCN counter, thus causing an underestimation of CCN activity. The effect of evaporation is clearly visible in all supersaturations, leading to an underestimation of the critical dry diameter by 10 to 15 nanometres in the case of ammonium nitrate particles in different supersaturations. This result was also confirmed by measurements in supersaturations between 0.1 and 0.7%.

  2. Simultaneous Retrieval of Aerosol and Surface Optical Properties from Combined Airborne- and Ground-Based Direct and Diffuse Radiometric Measurements

    NASA Technical Reports Server (NTRS)

    Gatebe, C. K.; Dubovik, O.; King, M. D.; Sinyuk, A.

    2010-01-01

    This paper presents a new method for simultaneously retrieving aerosol and surface reflectance properties from combined airborne and ground-based direct and diffuse radiometric measurements. The method is based on the standard Aerosol Robotic Network (AERONET) method for retrieving aerosol size distribution, complex index of refraction, and single scattering albedo, but modified to retrieve aerosol properties in two layers, below and above the aircraft, and parameters on surface optical properties from combined datasets (Cloud Absorption Radiometer (CAR) and AERONET data). A key advantage of this method is the inversion of all available spectral and angular data at the same time, while accounting for the influence of noise in the inversion procedure using statistical optimization. The wide spectral (0.34-2.30 m) and angular range (180 ) of the CAR instrument, combined with observations from an AERONET sunphotometer, provide sufficient measurement constraints for characterizing aerosol and surface properties with minimal assumptions. The robustness of the method was tested on observations made during four different field campaigns: (a) the Southern African Regional Science Initiative 2000 over Mongu, Zambia, (b) the Intercontinental Transport Experiment-Phase B over Mexico City, Mexico (c) Cloud and Land Surface Interaction Campaign over the Atmospheric Radiation Measurement (ARM) Central Facility, Oklahoma, USA, and (d) the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) over Elson Lagoon in Barrow, Alaska, USA. The four areas are dominated by different surface characteristics and aerosol types, and therefore provide good test cases for the new inversion method.

  3. Impact of Clouds and Aerosols on Photochemistry During the TexAQS II Radical and Aerosol Measurement Project

    NASA Astrophysics Data System (ADS)

    Flynn, J. H.; Lefer, B. L.; Rappenglueck, B.; Olson, J. R.; Chen, G.

    2007-12-01

    Photochemistry is responsible for the production of tropospheric ozone, the primary component of smog. In 2006, Houston, Texas experienced 20 days with a 1-hour ozone average in excess of 125 ppbv, and 36 days with an 8-hour average over 85 ppbv. Two models were used to assess the impact of clouds and aerosols on the photochemical production and loss of ozone and radicals in a polluted urban environment. The NASA Langley Research Center (LaRC) 0-D photochemical box model was used to assess the changes in the photochemical budgets due to varying cloud and aerosol conditions. The NCAR Tropospheric Ultraviolet and Visible (TUV) radiative transfer model was used to calculate photolysis frequencies for clear sky conditions with a variety of aerosol profiles. These tools were used to analyze the data set collected during the Texas Air Quality Study II Radical and Aerosol Measurement Project (TRAMP) with respect to ozone and radical budgets. Measurements of trace gasses, aerosols, meteorological parameters, and radiation were collected between mid-August and early October 2006 at the University of Houston. The photochemical model was run using various photolysis rates that reflect a range of atmospheric conditions impacting the actinic flux. Rates from real-time actinic flux measurements include the impact of both the clouds and aerosols that are present. Photolysis rates for clear-sky (cloud-free) conditions, both with and without aerosol profiles were calculated using the TUV radiative transfer model. A comparison of the photochemical ozone and radical budgets resulting from these different rates indicate those sensitivities to the presence of aerosols and clouds. Approximately seven of the 50 days during the campaign were cloud-free and were compared to LaRC-TUV results to show the effects of aerosols. The remaining days show the effects of both aerosols and cloud conditions that varied from partly cloudy to heavy overcast conditions. A cloud camera was used to

  4. Third Soviet-American Gases and Aerosols (SAGA 3) experiment: Overview and meteorological and oceanographic conditions

    NASA Astrophysics Data System (ADS)

    Johnson, J. E.; Koropalov, V. M.; Pickering, K. E.; Thompson, A. M.; Bond, N.; Elkins, J. W.

    1993-01-01

    The primary goal of the third joint Soviet-American Gases and Aerosols (SAGA 3) experiment was to study trace gases and aerosols in the remote marine boundary layer. SAGA 3/leg 1 took place from February 13 to March 13, 1990, aboard the former Soviet R/V Akademik Korolev and consisted of five equatorial transects (designated transects 1 through 5) between 15°N and 10°S on a cruise track from Hilo, Hawaii, to Pago-Pago, American Samoa. Specific objectives were to study (1) the oceanic distribution and air-sea exchange of biogenic trace gases; (2) photochemical cycles of C-, S-, and N-containing gases in the marine boundary layer; (3) the distribution of aerosol particles in the marine boundary layer and their physical and chemical properties; (4) interhemispheric gradients and latitudinal mixing of trace gases and aerosols; and (5) stratospheric aerosol layers. SAGA 3/leg 2 continued from March 17 to April 7, 1990, with one more equatorial transect between American Samoa and the northern coast of the Philippines (transect 6) followed by a final transect to Singapore (transect 7). During leg 2, most former Soviet measurements continued, but with the exception of measurements of nitrous oxide (N2O) and selected halocarbons in the air and surface waters all American measurements ceased. This paper briefly summarizes the chemical measurements made by SAGA 3 investigators and presents in some detail the meteorological and hydrological characteristics encountered during SAGA 3. The meteorological analysis is based on atmospheric soundings of temperature, humidity, winds, sea surface temperature, postcruise back trajectories of winds, and satellite imagery. In general, the meteorology during SAGA 3 was typical of the location and time of year. Exceptions to this include an incipient El Niño that never developed fully, a poorly defined ITCZ on 4 of 6 equator crossings, wind speeds that were 20% greater than the decadal mean, a convective event that brought

  5. Informing Aerosol Transport Models With Satellite Multi-Angle Aerosol Measurements

    NASA Technical Reports Server (NTRS)

    Limbacher, J.; Patadia, F.; Petrenko, M.; Martin, M. Val; Chin, M.; Gaitley, B.; Garay, M.; Kalashnikova, O.; Nelson, D.; Scollo, S.

    2011-01-01

    As the aerosol products from the NASA Earth Observing System's Multi-angle Imaging SpectroRadiometer (MISR) mature, we are placing greater focus on ways of using the aerosol amount and type data products, and aerosol plume heights, to constrain aerosol transport models. We have demonstrated the ability to map aerosol air-mass-types regionally, and have identified product upgrades required to apply them globally, including the need for a quality flag indicating the aerosol type information content, that varies depending upon retrieval conditions. We have shown that MISR aerosol type can distinguish smoke from dust, volcanic ash from sulfate and water particles, and can identify qualitative differences in mixtures of smoke, dust, and pollution aerosol components in urban settings. We demonstrated the use of stereo imaging to map smoke, dust, and volcanic effluent plume injection height, and the combination of MISR and MODIS aerosol optical depth maps to constrain wildfire smoke source strength. This talk will briefly highlight where we stand on these application, with emphasis on the steps we are taking toward applying the capabilities toward constraining aerosol transport models, planet-wide.

  6. 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.

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

    SciTech Connect

    Davidovits, Paul

    2011-12-10

    Soot particles are generated by incomplete combustion of fossil and biomass fuels. Through direct effects clear air aerosols containing black carbon (BC) such as soot aerosols, absorb incoming light heating the atmosphere, while most other aerosols scatter light and produce cooling. Even though BC represents only 1-2% of the total annual emissions of particulate mass to the atmosphere, it has been estimated that the direct radiative effect of BC is the second-most important contributor to global warming after absorption by CO2. Ongoing studies continue to underscore the climate forcing importance of black carbon. However, estimates of the radiative effects of black carbon on climate remain highly uncertain due to the complexity of particles containing black carbon. Quantitative measurement of BC is challenging because BC often occurs in highly non-spherical soot particles of complex morphology. Freshly emitted soot particles are typically fractal hydrophobic aggregates. The aggregates consist of black carbon spherules with diameters typically in the range of about 15-40 nm, and they are usually coated by adsorbed polyaromatic hydrocarbons (PAHs) produced during combustion. Diesel-generated soot particles are often emitted with an organic coating composed primarily of lubricating oil and unburned fuel, as well as well as PAH compounds. Sulfuric acid has also been detected in diesel and aircraft-emitted soot particles. In the course of aging, these particle coatings may be substantially altered by chemical reactions and/or the deposition of other materials. Such processes transform the optical and CCN properties of the soot aerosols in ways that are not yet well understood. Our work over the past seven years consisted of laboratory research, instrument development and characterization, and field studies with the central focus of improving our understanding of the black carbon aerosol climate impacts. During the sixth year as well as during this seventh year (no

  8. 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.

  9. 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.

  10. Measurement of the emission rate of an aerosol source--comparison of aerosol and gas transport coefficients.

    PubMed

    Bémer, D; Callé, S; Godinot, S; Régnier, R; Dessagne, J M

    2000-12-01

    A measuring method of the emission rate of an atmospheric pollutant source, based on the use of a tracer gas (helium) and developed in the case of a gaseous source, was tested for an aerosol source. The influence of both particle sedimentation and wall depositions was studied. The transport coefficients of the tracer gas and of alumina particles of various particle sizes (MMAD from 8 to 36 microns) were measured on a vertical axis close to the source, in a 71 m3 room swept by a piston flow. The measurements clearly demonstrated the predominant influence of sedimentation in the case of particles with aerodynamic diameters greater than 10 microns. Particle wall deposition was determined by measuring the gas and particle concentration decay in the ventilated room. To do this, a new tracing method using a fluorescent aerosol was developed. The measured aerosol deposition rates are much higher than those calculated from the formula of Corner for a cubical volume. Aerosol sedimentation and wall deposition are two phenomena limiting the use of a tracer gas to measure the aerosol emission rate. The chemical substances and materials used in work premises are likely to be released into the atmosphere and lead to the formation of pollutants. These emissions stem from either physical or chemical processes (evaporation of a solvent) or from mechanical processes (dispersion of oil droplets at the source of mists).

  11. Airborne Sunphotometer, Airborne in-situ, Space-borne, and Ground-Based Measurements of Troposoheric Aerosol in Ace-2

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Collins, D.; Gasso, S.; Ostrom, E.; Powell, D.; Welton, E.; Durkee, P.; Livingstron, J.; Russell, P.; Flagan, R.; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    We report on clear-sky column closure experiments performed in the Canary Islands during the second Aerosol Characterization Experiment (ACE-2) in June/July 1997. We present results obtained by combining airborne sunphotometer and in-situ aerosol measurements taken aboard the Pelican aircraft, space-borne NOAA/AVHRR data and ground-based lidars A wide range of aerosol types was encountered throughout the ACE-2 area, including background Atlantic marine, European pollution-derived, and African mineral dust. During !he two days discussed here, vertical profiles flown in cloud free air masses revealed three distinctly different layers: a marine boundary layer (MBL) with varying pollution levels, an elevated dust layer, and a very clean layer between the MBL and the dust layer. We found that the presence of the elevated dust layer removes the good agreement between satellite and sunphotometer AOD usually found in the absence of the dust layer. Using size-resolved composition information we have computed optical properties of the ambient aerosol from the in-situ measurements and subsequently compared those to the sunphotometer results. In the dust, the agreement in layer aerosol optical depth (380-1060 nm) is 3-8%. In the MBL there is tendency for the in-situ results to be slightly lower than the sunphotometer measurements (10-17% at 525 nm), but these differences are within the combined error bars of the measurements and computations.

  12. The investigation of advanced remote sensing techniques for the measurement of aerosol characteristics

    NASA Technical Reports Server (NTRS)

    Deepak, A.; Becher, J.

    1979-01-01

    Advanced remote sensing techniques and inversion methods for the measurement of characteristics of aerosol and gaseous species in the atmosphere were investigated. Of particular interest were the physical and chemical properties of aerosols, such as their size distribution, number concentration, and complex refractive index, and the vertical distribution of these properties on a local as well as global scale. Remote sensing techniques for monitoring of tropospheric aerosols were developed as well as satellite monitoring of upper tropospheric and stratospheric aerosols. Computer programs were developed for solving multiple scattering and radiative transfer problems, as well as inversion/retrieval problems. A necessary aspect of these efforts was to develop models of aerosol properties.

  13. Using OMI Observations to Measure Aerosol Absorption of Biomass Burning Aerosols Above Clouds

    NASA Technical Reports Server (NTRS)

    Torres, Omar; Bhartia, P. K.; Jethva, Hiren

    2011-01-01

    The presence of absorbing aerosol layers above clouds is unambiguously detected by the TOMS/OMI UV Aerosol Index (AI) that uses satellite observations at two near-UV channels. A sensitivity study using radiative transfer calculations shows that the AI signal of resulting from the presence of aerosols above clouds is mainly driven by the aerosol absorption optical depth and the optical depth of the underlying cloud. Based on these results, an inversion algorithm has been developed to retrieve the aerosol optical depth (AOD) of aerosol layers above clouds. In this presentation we will discuss the sensitivity analysis, describe the retrieval approach, and present results of applications of the retrieval method to OMI observations over the South Atlantic Ocean. Preliminary error analyses, to be discussed, indicate that the AOD can be underestimated (up to -30%) or overestimated (up to 60%) depending on algorithmic assumptions.

  14. Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx

    SciTech Connect

    Kleinman, L.I.; Daum, P. H.; Lee, Y.-N.; Lewis, E. R.; Sedlacek III, A. J.; Senum, G. I.; Springston, S. R.; Wang, J.; Hubbe, J.; Jayne, J.; Min, Q.; Yum, S. S.; Allen, G.

    2011-06-21

    During the VOCALS Regional Experiment, the DOE G-1 aircraft was used to sample a varying aerosol environment pertinent to properties of stratocumulus clouds over a longitude band extending 800 km west from the Chilean coast at Arica. Trace gas and aerosol measurements are presented as a function of longitude, altitude, and dew point in this study. Spatial distributions are consistent with an upper atmospheric source for O{sub 3} and South American coastal sources for marine boundary layer (MBL) CO and aerosol, most of which is acidic sulfate in agreement with the dominant pollution source being SO{sub 2} from Cu smelters and power plants. Pollutant layers in the free troposphere (FT) can be a result of emissions to the north in Peru or long range transport from the west. At a given altitude in the FT (up to 3 km), dew point varies by 40 C with dry air descending from the upper atmospheric and moist air having a BL contribution. Ascent of BL air to a cold high altitude results in the condensation and precipitation removal of all but a few percent of BL water along with aerosol that served as CCN. Thus, aerosol volume decreases with dew point in the FT. Aerosol size spectra have a bimodal structure in the MBL and an intermediate diameter unimodal distribution in the FT. Comparing cloud droplet number concentration (CDNC) and pre-cloud aerosol (Dp > 100 nm) gives a linear relation up to a number concentration of {approx}150 cm{sup -3}, followed by a less than proportional increase in CDNC at higher aerosol number concentration. A number balance between below cloud aerosol and cloud droplets indicates that {approx}25% of aerosol in the PCASP size range are interstitial (not activated). One hundred and two constant altitude cloud transects were identified and used to determine properties of interstitial aerosol. One transect is examined in detail as a case study. Approximately 25 to 50% of aerosol with D{sub p} > 110 nm were not activated, the difference between the two

  15. Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx

    NASA Astrophysics Data System (ADS)

    Kleinman, L. I.; Daum, P. H.; Lee, Y.-N.; Lewis, E. R.; Sedlacek, A. J., III; Senum, G. I.; Springston, S. R.; Wang, J.; Hubbe, J.; Jayne, J.; Min, Q.; Yum, S. S.; Allen, G.

    2011-06-01

    During the VOCALS Regional Experiment, the DOE G-1 aircraft was used to sample a varying aerosol environment pertinent to properties of stratocumulus clouds over a longitude band extending 800 km west from the Chilean coast at Arica. Trace gas and aerosol measurements are presented as a function of longitude, altitude, and dew point in this study. Spatial distributions are consistent with an upper atmospheric source for O3 and South American coastal sources for marine boundary layer (MBL) CO and aerosol, most of which is acidic sulfate in agreement with the dominant pollution source being SO2 from Cu smelters and power plants. Pollutant layers in the free troposphere (FT) can be a result of emissions to the north in Peru or long range transport from the west. At a given altitude in the FT (up to 3 km), dew point varies by 40 °C with dry air descending from the upper atmospheric and moist air having a BL contribution. Ascent of BL air to a cold high altitude results in the condensation and precipitation removal of all but a few percent of BL water along with aerosol that served as CCN. Thus, aerosol volume decreases with dew point in the FT. Aerosol size spectra have a bimodal structure in the MBL and an intermediate diameter unimodal distribution in the FT. Comparing cloud droplet number concentration (CDNC) and pre-cloud aerosol (Dp > 100 nm) gives a linear relation up to a number concentration of ~150 cm-3, followed by a less than proportional increase in CDNC at higher aerosol number concentration. A number balance between below cloud aerosol and cloud droplets indicates that ~25 % of aerosol in the PCASP size range are interstitial (not activated). One hundred and two constant altitude cloud transects were identified and used to determine properties of interstitial aerosol. One transect is examined in detail as a case study. Approximately 25 to 50 % of aerosol with Dp > 110 nm were not activated, the difference between the two approaches possibly representing

  16. 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

  17. Laser Propagation Experiments - Aerosol and Stagnation Zone Effects

    DTIC Science & Technology

    1977-08-01

    Phys. 46, 402 (1975). 5. D. E. Lencioni and H. Kleiman. Effects of Aerosol Particle Heating on Laser Beam Propagation, Project Report LTP -27 on...1977. 18. J. Herrmann and L. C. Bradley. Numerical Calculations of Light Propagat , MIT/Lincln Laboratory Laser Technology Program Report LTP -10...R77-922578-13 ,/ Laser Propagation Experimets Aerosol and Stagnation "Zone Effects Final Technical Report "June 19, 1977 M.C. Fowe; J.R. Dunphy 3.3 0

  18. Aerosol absorption measurement with a sinusoidal phase modulating fiber optic photo thermal interferometer

    NASA Astrophysics Data System (ADS)

    Li, Shuwang; Shao, Shiyong; Mei, Haiping; Rao, Ruizhong

    2016-10-01

    Aerosol light absorption plays an important role in the earth's atmosphere direct and semi-direct radiate forcing, simultaneously, it also has a huge influence on the visibility impairment and laser engineering application. Although various methods have been developed for measuring aerosol light absorption, huge challenge still remains in precision, accuracy and temporal resolution. The main reason is that, as a part of aerosol light extinction, aerosol light absorption always generates synchronously with aerosol light scattering, and unfortunately aerosol light scattering is much stronger in most cases. Here, a novel photo-thermal interferometry is proposed only for aerosol absorption measurement without disturbance from aerosol scattering. The photo-thermal interferometry consists of a sinusoidal phase-modulating single mode fiber-optic interferometer. The thermal dissipation, caused by aerosol energy from photo-thermal conversion when irritated by pump laser through interferometer, is detected. This approach is completely insensitive to aerosol scattering, and the single mode fiber-optic interferometer is compact, low-cost and insensitive to the polarization shading. The theory of this technique is illustrated, followed by the basic structure of the sinusoidal phase-modulating fiber-optic interferometer and demodulation algorithms. Qualitative and quantitative analysis results show that the new photo-thermal interference is a potential approach for aerosol absorption detection and environmental pollution detection.

  19. High sensitivity sensor for continuous direct measurement of bipolar charged aerosols

    NASA Astrophysics Data System (ADS)

    Baxter, Karen; Jones, Chris; Fletcher-Wood, Guy

    2008-12-01

    The disruptive generation of aerosols is known to cause particles to carry electrostatic charges. Anthropogenic aerosol may have a standard deviation of charges when generated that is different to other sources or equilibrated aerosols. A simple, low cost 'Bipolar Charged Aerosol Sensor' (BCAS) has been developed to continuously measure charged aerosol in the ambient environment in real-time. Direct measurement of the current released from the charged aerosol particles when they deposit onto an electrode in a DC field is achieved using custom designed, sensitive electrometers. The mobility range of particles collected is defined by the DC field strength, air flow rate through the instrument and the electrode geometry. The mobility range of interest has been selected based on measurements made previously with a complex Laser Doppler Velocimetry (LDV) based instrument. The BCAS has been assessed in laboratory. The sensor design and initial measurement data will be discussed.

  20. Aerosol/Cloud Measurements Using Coherent Wind Doppler Lidars

    NASA Astrophysics Data System (ADS)

    Royer, Philippe; Boquet, Matthieu; Cariou, Jean-Pierre; Sauvage, Laurent; Parmentier, Rémy

    2016-06-01

    The accurate localization and characterization of aerosol and cloud layers is crucial for climate studies (aerosol indirect effect), meteorology (Planetary Boundary Layer PBL height), site monitoring (industrial emissions, mining,…) and natural hazards (thunderstorms, volcanic eruptions). LEOSPHERE has recently developed aerosol/cloud detection and characterization on WINDCUBE long range Coherent Wind Doppler Lidars (CWDL). These new features combine wind and backscatter intensity informations (Carrier-to-Noise Ratio CNR) in order to detect (aerosol/cloud base and top, PBL height) and to characterize atmospheric structures (attenuated backscatter, depolarization ratio). For each aerosol/cloud functionality the method is described, limitations are discussed and examples are given to illustrate the performances.

  1. 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.

  2. Intercomparison of aerosol extinction profiles retrieved from MAX-DOAS measurements

    NASA Astrophysics Data System (ADS)

    Frieß, U.; Klein Baltink, H.; Beirle, S.; Clémer, K.; Hendrick, F.; Henzing, B.; Irie, H.; de Leeuw, G.; Li, A.; Moerman, M. M.; van Roozendael, M.; Shaiganfar, R.; Wagner, T.; Wang, Y.; Xie, P.; Yilmaz, S.; Zieger, P.

    2016-07-01

    A first direct intercomparison of aerosol vertical profiles from Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations, performed during the Cabauw Intercomparison Campaign of Nitrogen Dioxide measuring Instruments (CINDI) in summer 2009, is presented. Five out of 14 participants of the CINDI campaign reported aerosol extinction profiles and aerosol optical thickness (AOT) as deduced from observations of differential slant column densities of the oxygen collision complex (O4) at different elevation angles. Aerosol extinction vertical profiles and AOT are compared to backscatter profiles from a ceilometer instrument and to sun photometer measurements, respectively. Furthermore, the near-surface aerosol extinction coefficient is compared to in situ measurements of a humidity-controlled nephelometer and dry aerosol absorption measurements. The participants of this intercomparison exercise use different approaches for the retrieval of aerosol information, including the retrieval of the full vertical profile using optimal estimation and a parametrised approach with a prescribed profile shape. Despite these large conceptual differences, and also differences in the wavelength of the observed O4 absorption band, good agreement in terms of the vertical structure of aerosols within the boundary layer is achieved between the aerosol extinction profiles retrieved by the different groups and the backscatter profiles observed by the ceilometer instrument. AOTs from MAX-DOAS and sun photometer show a good correlation (R>0.8), but all participants systematically underestimate the AOT. Substantial differences between the near-surface aerosol extinction from MAX-DOAS and from the humidified nephelometer remain largely unresolved.

  3. Improved Tandem Measurement Techniques for Aerosol Particle Analysis

    NASA Astrophysics Data System (ADS)

    Rawat, Vivek Kumar

    Non-spherical, chemically inhomogeneous (complex) nanoparticles are encountered in a number of natural and engineered environments, including combustion systems (which produces highly non-spherical aggregates), reactors used in gas-phase materials synthesis of doped or multicomponent materials, and in ambient air. These nanoparticles are often highly diverse in size, composition and shape, and hence require determination of property distribution functions for accurate characterization. This thesis focuses on development of tandem mobility-mass measurement techniques coupled with appropriate data inversion routines to facilitate measurement of two dimensional size-mass distribution functions while correcting for the non-idealities of the instruments. Chapter 1 provides the detailed background and motivation for the studies performed in this thesis. In chapter 2, the development of an inversion routine is described which is employed to determine two dimensional size-mass distribution functions from Differential Mobility Analyzer-Aerosol Particle Mass analyzer tandem measurements. Chapter 3 demonstrates the application of the two dimensional distribution function to compute cumulative mass distribution function and also evaluates the validity of this technique by comparing the calculated total mass concentrations to measured values for a variety of aerosols. In Chapter 4, this tandem measurement technique with the inversion routine is employed to analyze colloidal suspensions. Chapter 5 focuses on application of a transverse modulation ion mobility spectrometer coupled with a mass spectrometer to study the effect of vapor dopants on the mobility shifts of sub 2 nm peptide ion clusters. These mobility shifts are then compared to models based on vapor uptake theories. Finally, in Chapter 6, a conclusion of all the studies performed in this thesis is provided and future avenues of research are discussed.

  4. The System of the Calibration for Visibility Measurement Instrument Under the Atmospheric Aerosol Simulation Environment

    NASA Astrophysics Data System (ADS)

    Shu, Zhifeng; Yang, ShaoChen; Xu, Wenjing

    2016-06-01

    divided by 3 is MOR. The aerosol concentration in chamber can be changed by adjusting aerosol generator that producing variety of visibility atmospherical environment. The experiment has been carried out and the measurement accuracy of atmospheric transmittance is 0.3‰ Corresponding to the accuracy of MOR 4.9% at the 2km visibility environment. So this system can be calibrated and validated the other visibility measuring devices.

  5. Generation and characterization of biological aerosols for laser measurements

    SciTech Connect

    Cheng, Yung-Sung; Barr, E.B.

    1995-12-01

    Concerns for proliferation of biological weapons including bacteria, fungi, and viruses have prompted research and development on methods for the rapid detection of biological aerosols in the field. Real-time instruments that can distinguish biological aerosols from background dust would be especially useful. Sandia National Laboratories (SNL) is developing a laser-based, real-time instrument for rapid detection of biological aerosols, and ITRI is working with SNL scientists and engineers to evaluate this technology for a wide range of biological aerosols. This paper describes methods being used to generate the characterize the biological aerosols for these tests. In summary, a biosafe system has been developed for generating and characterizing biological aerosols and using those aerosols to test the SNL laser-based real-time instrument. Such tests are essential in studying methods for rapid detection of airborne biological materials.

  6. Airborne measurements of biomass burning aerosol distribution and composition in the springtime Arctic 2008

    NASA Astrophysics Data System (ADS)

    Thornberry, T.; Froyd, K. D.; Murphy, D. M.; Thomson, D. S.; Brock, C. A.; Cozic, J.; Warneke, C.; Degouw, J.; Middlebrook, A. M.; Bahreini, R.; Brioude, J.

    2008-12-01

    The springtime Arctic troposphere in 2008 was characterized by high concentrations of biomass burning aerosol. During the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) campaign, airborne measurements of aerosol composition by the NOAA single particle mass spectrometer instrument (PALMS) identified biomass burning particles using an established composition tracer. Fires in northern Asia produced biomass burning aerosol that were transported to the Arctic within 3-12 days. Concentrations of biomass burning aerosols were elevated not only within well defined plumes, but also regionally throughout the Arctic. Above the boundary layer, biomass burning particles dominated the total aerosol volume and were largely responsible for the Arctic Haze observed during the period of study. The composition of plume aerosols varied according to source region, transport time, and anthropogenic influence.

  7. Impact of Tropospheric Aerosol Absorption on Ozone Retrieval from buv Measurements

    NASA Technical Reports Server (NTRS)

    Torres, O.; Bhartia, P. K.

    1998-01-01

    The impact of tropospheric aerosols on the retrieval of column ozone amounts using spaceborne measurements of backscattered ultraviolet radiation is examined. Using radiative transfer calculations, we show that uv-absorbing desert dust may introduce errors as large as 10% in ozone column amount, depending on the aerosol layer height and optical depth. Smaller errors are produced by carbonaceous aerosols that result from biomass burning. Though the error is produced by complex interactions between ozone absorption (both stratospheric and tropospheric), aerosol scattering, and aerosol absorption, a surprisingly simple correction procedure reduces the error to about 1%, for a variety of aerosols and for a wide range of aerosol loading. Comparison of the corrected TOMS data with operational data indicates that though the zonal mean total ozone derived from TOMS are not significantly affected by these errors, localized affects in the tropics can be large enough to seriously affect the studies of tropospheric ozone that are currently undergoing using the TOMS data.

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

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  9. Highly Resolved Aerosol Measurements from High Altitude Platforms

    NASA Technical Reports Server (NTRS)

    Wilson, James Charles

    1999-01-01

    The University of Denver agreed to develop and fabricate two instruments for the characterization of submicron aerosol. The instruments were to be light weight for use on remotely-piloted aircraft or balloons. The instruments were to provide accurate size measurements of size distributions in the size range from 0.07 to 2 micrometers in diameter and concentration measurements in the size range approximately 0.01 to 2 micrometers in diameter. The instruments constructed under this cooperative agreement respond quite nearly as expected and meet the objective of being light and compact. One has been used for ground based and low altitude studies and the other will be deployed in high altitude studies this winter.

  10. Error in total ozone measurements arising from aerosol attenuation

    NASA Technical Reports Server (NTRS)

    Thomas, R. W. L.; Basher, R. E.

    1979-01-01

    A generalized least squares method for deducing both total ozone and aerosol extinction spectrum parameters from Dobson spectrophotometer measurements was developed. An error analysis applied to this system indicates that there is little advantage to additional measurements once a sufficient number of line pairs have been employed to solve for the selected detail in the attenuation model. It is shown that when there is a predominance of small particles (less than about 0.35 microns in diameter) the total ozone from the standard AD system is too high by about one percent. When larger particles are present the derived total ozone may be an overestimate or an underestimate but serious errors occur only for narrow polydispersions.

  11. 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

  12. Intercomparison of an Aerosol Chemical Speciation Monitor (ACSM) with ambient fine aerosol measurements in downtown Atlanta, Georgia

    NASA Astrophysics Data System (ADS)

    Budisulistiorini, S. H.; Canagaratna, M. R.; Croteau, P. L.; Baumann, K.; Edgerton, E. S.; Kollman, M. S.; Ng, N. L.; Verma, V.; Shaw, S. L.; Knipping, E. M.; Worsnop, D. R.; Jayne, J. T.; Weber, R. J.; Surratt, J. D.

    2014-07-01

    Currently, there are a limited number of field studies that evaluate the long-term performance of the Aerodyne Aerosol Chemical Speciation Monitor (ACSM) against established monitoring networks. In this study, we present seasonal intercomparisons of the ACSM with collocated fine aerosol (PM2.5) measurements at the Southeastern Aerosol Research and Characterization (SEARCH) Jefferson Street (JST) site near downtown Atlanta, GA, during 2011-2012. Intercomparison of two collocated ACSMs resulted in strong correlations (r2 > 0.8) for all chemical species, except chloride (r2 = 0.21) indicating that ACSM instruments are capable of stable and reproducible operation. In general, speciated ACSM mass concentrations correlate well (r2 > 0.7) with the filter-adjusted continuous measurements from JST, although the correlation for nitrate is weaker (r2 = 0.55) in summer. Correlations of the ACSM NR-PM1 (non-refractory particulate matter with aerodynamic diameter less than or equal to 1 μm) plus elemental carbon (EC) with tapered element oscillating microbalance (TEOM) PM2.5 and Federal Reference Method (FRM) PM1 mass are strong with r2 > 0.7 and r2 > 0.8, respectively. Discrepancies might be attributed to evaporative losses of semi-volatile species from the filter measurements used to adjust the collocated continuous measurements. This suggests that adjusting the ambient aerosol continuous measurements with results from filter analysis introduced additional bias to the measurements. We also recommend to calibrate the ambient aerosol monitoring instruments using aerosol standards rather than gas-phase standards. The fitting approach for ACSM relative ionization for sulfate was shown to improve the comparisons between ACSM and collocated measurements in the absence of calibrated values, suggesting the importance of adding sulfate calibration into the ACSM calibration routine.

  13. Aerosol optical hygroscopicity measurements during the 2010 CARES campaign

    DOE PAGES

    Atkinson, D. B.; Radney, J. G.; Lum, J.; ...

    2015-04-17

    Measurements of the effect of water uptake on particulate light extinction or scattering made at two locations during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) study around Sacramento, CA are reported. The observed influence of water uptake, characterized through the dimensionless optical hygroscopicity parameter γ, is compared with calculations constrained by observed particle size distributions and size-dependent particle composition. A closure assessment has been carried out that allowed for determination of the average hygroscopic growth factors (GFs) at 85% relative humidity and the dimensionless hygroscopicity parameter κ for oxygenated organic aerosol (OA) and for supermicron particles (defined heremore » as particles with aerodynamic diameters between 1 and 2.5 microns), yielding κ = 0.1–0.15 and 0.9–1.0, respectively. The derived range of oxygenated OA κ values are in line with previous observations. The relatively large values for supermicron particles is consistent with substantial contributions of sea-salt-containing particles in this size range. Analysis of time-dependent variations in the supermicron particle hygroscopicity suggest that atmospheric processing, specifically chloride displacement by nitrate and the accumulation of secondary organics on supermicron particles, can lead to substantial depression of the observed GF.« less

  14. Aerosol measurements of long range transport events from Asia

    NASA Astrophysics Data System (ADS)

    Hudson, P.; Murphy, D.; Cziczo, D.; Thomson, D.; Brock, C.; Wilson, C.; Weber, R.; Sullivan, A.; Orsini, D.

    2003-04-01

    The Intercontinental Transport and Chemical Transformation (ITCT) mission (Monterey, CA, spring 2002) investigated the gas phase and particulate composition of air masses along the western coast of the United States using a host of gas and aerosol instruments aboard the WP-3 aircraft. Several transport events from Asia containing enhanced number and mass concentrations of particles were intercepted during the mission. Within these different layers, a variety of particle modes and compositions were observed, including a) coarse crustal particles transported in the absence of anthropogenic trace gases, b) nucleation-mode particles associated with substantial enhancements in CO, NO_y, and organic tracers of biomass and anthropogenic emissions, and c) accumulation-mode particles found in the presence of CO and HNO_3. The properties, sources, and transport of these different aerosols will be evaluated using individual particle and bulk composition measurements and particle size distributions as determined from the PALMS (Particle Analysis by Laser Mass Spectrometry), PILS (Particle Into Liquid Sampling), and particle size spectrometers, respectively.

  15. Compact Efficient Lidar Receiver for Measuring Atmospheric Aerosols

    NASA Technical Reports Server (NTRS)

    Gili, Christopher; De Young, Russell

    2006-01-01

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

  16. Lidar measurements of the post-fuego stratospheric aerosol

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Hake, R. D., Jr.; Viezee, W.

    1976-01-01

    Fifteen lidar observations of the stratospheric aerosol were made between February and November 1975. All observations revealed the greatly increased particulate backscattering that followed the eruption of the volcano Fuego in October 1974. Vertical structure consisted initially of multiple layers, which later merged to form a single, broader peak. Essentially all of the increased scattering was confined to altitudes below 20 km. Hence, aerosol layer centroids in 1975 were typically several km below their altitude prior to the eruption. Radiative and thermal consequences of the measured post-Fuego layer were computed using several recently published models. The models predict a temperature increase of several K at the altitude of the layer, caused by the infrared absorption bands of the sulfuric acid particles. The surface temperature decrease predicted by the models is considerably smaller than 1 K, partly because of the small optical thickness of the volcanic layer, and partly because of its short residence time relative to the earth-ocean thermal response time.

  17. Aerosol properties derived from airborne sky radiance and direct beam measurements in recent NASA and DoE field campaigns

    NASA Astrophysics Data System (ADS)

    Redemann, J.; Flynn, C. J.; Shinozuka, Y.; Russell, P. B.; Kacenelenbogen, M. S.; Segal-Rosenhaimer, M.; Livingston, J. M.; Schmid, B.; Dunagan, S. E.; Johnson, R. R.; LeBlanc, S. E.; Schmidt, S.; Pilewskie, P.; Song, S.

    2014-12-01

    The AERONET (AErosol RObotic NETwork) ground-based suite of sunphotometers provides measurements of spectral aerosol optical depth (AOD), precipitable water and spectral sky radiance, which can be inverted to retrieve aerosol microphysical properties that are critical to assessments of aerosol-climate interactions. Because of data quality criteria and sampling constraints, there are significant limitations to the temporal and spatial coverage of AERONET data and their representativeness for global aerosol conditions. The 4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research) instrument, jointly developed by NASA Ames and PNNL with NASA Goddard collaboration, combines airborne sun tracking and AERONET-like sky scanning with spectroscopic detection. Being an airborne instrument, 4STAR has the potential to fill gaps in the AERONET data set. The 4STAR instrument operated successfully in the SEAC4RS [Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys] experiment in Aug./Sep. 2013 aboard the NASA DC-8 and in the DoE [Department of Energy]-sponsored TCAP [Two Column Aerosol Project, July 2012 & Feb. 2013] experiment aboard the DoE G-1 aircraft. 4STAR provided direct beam measurements of hyperspectral AOD, columnar trace gas retrievals (H2O, O3, NO2), and the first ever airborne hyperspectral sky radiance scans, which can be inverted to yield the same products as AERONET ground-based observations. In this presentation, we provide an overview of the new 4STAR capabilities, with an emphasis on 26 high-quality sky radiance measurements carried out by 4STAR in SEAC4RS. We compare collocated 4STAR and AERONET sky radiances, as well as their retrievals of aerosol microphysical properties for a subset of the available case studies. We summarize the particle property and airmass characterization studies made possible by the combined 4STAR direct beam and sky radiance observations.

  18. Aerosol Properties Derived from Airborne Sky Radiance and Direct Beam Measurements in Recent NASA and DoE Field Campaigns

    NASA Technical Reports Server (NTRS)

    Redemann, J.; Flynn, C. J.; Shinozuka, Y.; Russell, P. B.; Kacenelenbogen, M.; Segal-Rosenheimer, M.; Livingston, J. M.; Schmid, B.; Dunagan, S. E.; Johnson, R. R.; LeBlanc, S.; Schmidt, S.; Pilewskie, P.; Song, S.

    2014-01-01

    The AERONET (AErosol RObotic NETwork) ground-based suite of sunphotometers provides measurements of spectral aerosol optical depth (AOD), precipitable water and spectral sky radiance, which can be inverted to retrieve aerosol microphysical properties that are critical to assessments of aerosol-climate interactions. Because of data quality criteria and sampling constraints, there are significant limitations to the temporal and spatial coverage of AERONET data and their representativeness for global aerosol conditions.The 4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research) instrument, jointly developed by NASA Ames and PNNL (Pacific Northwest National Laboratory) with NASA Goddard collaboration, combines airborne sun tracking and AERONET-like sky scanning with spectroscopic detection. Being an airborne instrument, 4STAR has the potential to fill gaps in the AERONET data set. The 4STAR instrument operated successfully in the SEAC4RS (Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys) experiment in Aug./Sep. 2013 aboard the NASA DC-8 and in the DoE (Department of Energy)-sponsored TCAP (Two Column Aerosol Project, July 2012 & Feb. 2013) experiment aboard the DoE G-1 aircraft. 4STAR provided direct beam measurements of hyperspectral AOD, columnar trace gas retrievals (H2O, O3, NO2), and the first ever airborne hyperspectral sky radiance scans, which can be inverted to yield the same products as AERONET ground-based observations. In this presentation, we provide an overview of the new 4STAR capabilities, with an emphasis on 26 high-quality sky radiance measurements carried out by 4STAR in SEAC4RS. We compare collocated 4STAR and AERONET sky radiances, as well as their retrievals of aerosol microphysical properties for a subset of the available case studies. We summarize the particle property and air-mass characterization studies made possible by the combined 4STAR direct beam and sky radiance

  19. Aerosol optical and microphysical properties from POLDER-PARASOL multi-angle photo-polarimetric measurements

    NASA Astrophysics Data System (ADS)

    Hasekamp, O.; Litvinov, P.; Butz, A.

    2010-12-01

    The large uncertainty on the aerosol effects on clouds and climate is reflected in considerable discrepancies between different model simulations of the radiative forcing caused by these effects. Also, there exist even larger differences between values for radiative forcing calculated by models and those estimated from satellites (and model calculations constrained by satellite measurements). Relationships between aerosols and clouds derived from satellite measurements are subject to a number of important limitations. First of all, with current satellite aerosol products it is hard to determine which fraction of the aerosols is anthropogenic and which fraction is natural. Often the rather crude assumption is used that the fine mode contribution is fully anthropogenic. Furthermore, most aerosol types are strongly hygroscopic, which means that in an environment with high relative humidity (in the surrounding of clouds) the particle size increases considerably leading, in turn, to an increase in optical thickness. This effect may be misinterpreted as an apparent relation between aerosol concentration and cloud cover. Also, meteorology effects can be misinterpreted as apparent aerosol-cloud relationships. Accurate information on aerosol size and refractive index (related to chemical composition of aerosols and absorption) is needed to distinguish between natural and anthropogenic aerosols and to distinguish between aerosol effects on cloud formation and apparent relationships due to humidity and meteorology effects. Multi-angle photopolarimetric measurements have the potential to provide the necessary information on these aerosol properties. The POLDER instrument onboard the PARASOL micro-satellite is the only instrument currently in space that performs multi-angle photopolarimetric measurements. To fully exploit the information contained in these measurements a new type of retrieval algorithm is needed that retrieves detailed information on aerosol microphysical and

  20. Changes in Antarctic stratospheric aerosol characteristics due to volcanic eruptions as monitored by the Stratospheric Aerosol and Gas Experiment II satellite

    NASA Astrophysics Data System (ADS)

    Saxena, V. K.; Anderson, John; Lin, N.-H.

    1995-08-01

    An estimated 20-30 megatons of SO2 and crustal material was injected into the stratosphere during June 12-16, 1991, by the eruption of Mount Pinatubo (15.1°N, 120.4°E). The impact on Antarctic aerosol characteristics is of utmost concern owing to the seasonality in the observed ozone depletion and climate implications. This study focuses on Antarctic stratospheric aerosol characteristics during three temporal periods: September 23-30, September 30 to October 13, and November 13-27, 1991, at latitudes poleward of 60°S for vertically averaged characteristics, and at latitudes poleward of 50°S for temporal and spatial characteristics. Stratospheric aerosol characteristics are inferred from the Stratospheric Aerosol and Gas Experiment (SAGE) II measurements using a modified randomized minimization search technique (RMST). Aerosol characteristics such as size distribution, number concentration, mass loading, surface area concentration, and radial characteristics are derived between 15 and 30 km for particles having radii between 0.1 and 0.8 μm. Results indicate that aerosol size distributions between 15 and 30 km are bimodal in several instances for all three time periods and can be fitted with the sum of two lognormal distributions. Larger concentrations are observed for particles of all sizes between 18 and 30 km during November 1991, signaling the arrival of the Mount Pinatubo plume. An order of magnitude increase in concentration is observed for particles with radii between 0.1 and 0.2 μm and between 0.7 and 0.8 μm. Vertical aerosol profiles show that the peak in aerosol concentration shifted to a higher altitude between 21 and 26 km as compared to the preplume peak between 15 and 18 km. Using the displacement as a function of time for a mass loading of 1.7 μg m-3 isopleth, we estimated meridional velocity ≈0.9 m s-1, zonal velocity ≈16 m s-1, and downward vertical velocity of 0.5 cm s-1 during September to mid-October, 1991, and 0.3 cm s-1 during mid to

  1. Aerosol Optical Properties Measured Onboard the Ronald H. Brown During ACE Asia as a Function of Aerosol Chemical Composition and Source Region

    NASA Technical Reports Server (NTRS)

    Quinn, P. K.; Coffman, D. J.; Bates, T. S.; Welton, E. J.; Covert, D. S.; Miller, T. L.; Johnson, J. E.; Maria, S.; Russell, L.; Arimoto, R.

    2004-01-01

    During the ACE Asia intensive field campaign conducted in the spring of 2001 aerosol properties were measured onboard the R/V Ronald H. Brown to study the effects of the Asian aerosol on atmospheric chemistry and climate in downwind regions. Aerosol properties measured in the marine boundary layer included chemical composition; number size distribution; and light scattering, hemispheric backscattering, and absorption coefficients. In addition, optical depth and vertical profiles of aerosol 180 deg backscatter were measured. Aerosol within the ACE Asia study region was found to be a complex mixture resulting from marine, pollution, volcanic, and dust sources. Presented here as a function of air mass source region are the mass fractions of the dominant aerosol chemical components, the fraction of the scattering measured at the surface due to each component, mass scattering efficiencies of the individual components, aerosol scattering and absorption coefficients, single scattering albedo, Angstrom exponents, optical depth, and vertical profiles of aerosol extinction. All results except aerosol optical depth and the vertical profiles of aerosol extinction are reported at a relative humidity of 55 +/- 5%. An over-determined data set was collected so that measured and calculated aerosol properties could be compared, internal consistency in the data set could be assessed, and sources of uncertainty could be identified. By taking into account non-sphericity of the dust aerosol, calculated and measured aerosol mass and scattering coefficients agreed within overall experimental uncertainties. Differences between measured and calculated aerosol absorption coefficients were not within reasonable uncertainty limits, however, and may indicate the inability of Mie theory and the assumption of internally mixed homogeneous spheres to predict absorption by the ACE Asia aerosol. Mass scattering efficiencies of non-sea salt sulfate aerosol, sea salt, submicron particulate organic

  2. Analysis of Measurement Requirements for the Aerosol Indirect Effect: A Synthesis of Observations and Modeling

    NASA Astrophysics Data System (ADS)

    Feingold, G.; Previdi, M.; Veron, D. E.

    2003-12-01

    The aerosol indirect effect has been measured for some time now by satellite remote sensors, and more recently by surface-based remote sensors. The indirect effect is often expressed in terms of a relative change in drop size for a relative change in aerosol optical depth or extinction. Here we present some recent results of surface based remote sensing of the indirect effect and assess whether aerosol optical depth or extinction is a suitable proxy for the aerosol affecting drop formation. To do so, we use multiple realizations of a cloud model to investigate the sensitivity of cloud drop effective radius re to aerosol parameters (size distribution and composition) and dynamical parameters (updraft and liquid water content). A breakdown of the individual aerosol terms contributing to drop size change shows that use of aerosol extinction as a proxy for size distribution and composition tends to underestimate the magnitude of the first indirect effect. The use of the aerosol index alleviates this problem somewhat. We show that re is most sensitive to cloud liquid water, a parameter often ignored in indirect effect analyses. The relative importance of the other parameters varies for different conditions but aerosol concentration Na is consistently important. Updraft plays an increasingly important role under high aerosol loadings. Requirements for measuring the indirect effect over polluted continents are shown to be more stringent than those over cleaner, remote oceans. This may influence interpretation of current satellite and surface remote measurements of the indirect effect.

  3. Jet and ultrasonic nebuliser output: use of a new method for direct measurement of aerosol output.

    PubMed Central

    Dennis, J H; Stenton, S C; Beach, J R; Avery, A J; Walters, E H; Hendrick, D J

    1990-01-01

    Output from jet nebulisers is calibrated traditionally by weighing them before and after nebulisation, but the assumption that the weight difference is a close measure of aerosol generation could be invalidated by the concomitant process of evaporation. A method has been developed for measuring aerosol output directly by using a solute (fluoride) tracer and aerosol impaction, and this has been compared with the traditional weight loss method for two Wright, six Turbo, and four Micro-Cirrus jet nebulisers and two Microinhaler ultrasonic nebulisers. The weight loss method overestimated true aerosol output for all jet nebulisers. The mean aerosol content, expressed as a percentage of the total weight loss, varied from as little as 15% for the Wright jet nebulisers to 54% (range 45-61%) for the Turbo and Micro-Cirrus jet nebulisers under the operating conditions used. In contrast, there was no discrepancy between weight loss and aerosol output for the ultrasonic nebulisers. These findings, along with evidence of both concentrating and cooling effects from jet nebulisation, confirm that total output from jet nebulisers contains two distinct fractions, vapour and aerosol. The vapour fraction, but not the aerosol fraction, was greatly influenced by reservoir temperature within the nebuliser; so the ratio of aerosol output to total weight loss varied considerably with temperature. It is concluded that weight loss is an inappropriate method of calibrating jet nebuliser aerosol output, and that this should be measured directly. PMID:2247862

  4. In Situ Aerosol Properties Measured over the California Central Valley and the Sierra Nevada Mountain Range

    NASA Astrophysics Data System (ADS)

    Tomlinson, J. M.; Comstock, J. M.; Hubbe, J.; Kluzek, C.; Schmid, B.; Jonsson, H.; Woods, R.

    2011-12-01

    Anthropogenic aerosols are hypothesized to influence the formation of clouds and precipitation amounts within the Sierra Nevada Mountains. This could have a profound effect on the California water supply. To study this phenomena, an Ultra High Sensitivity Aerosol Spectrometer (UHSAS), Passive Cavity Aerosol Spectrometer (PCASP), and Cloud Aerosol Spectrometer (CAS) were operated aboard the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Aerial Facility (AAF) Gulfstream-1 aircraft from February 2 to March 6, 2011 during the CalWater field campaign. The combined aerosol size distribution from the three instruments characterizes the size-resolved concentration of the submicron and supermicron aerosol over the California Central Valley and Sierra Nevada Mountain Range. The measured aerosol size distributions from CalWater are compared with the size distributions measured during the DOE Carbonaceous Aerosol and Radiative Effects Study (CARES) in June 2010 to determine the changes in the aerosol size distributions during different seasons, atmospheric river events, and long-range transport events from Asia. These changes are used to estimate the resulting aerosol effect on cloud condensation nuclei concentrations and the potential impact on cloud formation and precipitation.

  5. Performance of the Lidar Design and Data Algorithms for the GLAS Global Cloud and Aerosol Measurements

    NASA Technical Reports Server (NTRS)

    Spinhirne, James D.; Palm, Stephen P.; Hlavka, Dennis L.; Hart, William D.

    2007-01-01

    The Geoscience Laser Altimeter System (GLAS) launched in early 2003 is the first polar orbiting satellite lidar. The instrument design includes high performance observations of the distribution and optical scattering cross sections of atmospheric clouds and aerosol. The backscatter lidar operates at two wavelengths, 532 and 1064 nm. For the atmospheric cloud and aerosol measurements, the 532 nm channel was designed for ultra high efficiency with solid state photon counting detectors and etalon filtering. Data processing algorithms were developed to calibrate and normalize the signals and produce global scale data products of the height distribution of cloud and aerosol layers and their optical depths and particulate scattering cross sections up to the limit of optical attenuation. The paper will concentrate on the effectiveness and limitations of the lidar channel design and data product algorithms. Both atmospheric receiver channels meet and exceed their design goals. Geiger Mode Avalanche Photodiode modules are used for the 532 nm signal. The operational experience is that some signal artifacts and non-linearity require correction in data processing. As with all photon counting detectors, a pulse-pile-up calibration is an important aspect of the measurement. Additional signal corrections were found to be necessary relating to correction of a saturation signal-run-on effect and also for daytime data, a small range dependent variation in the responsivity. It was possible to correct for these signal errors in data processing and achieve the requirement to accurately profile aerosol and cloud cross section down to 10-7 llm-sr. The analysis procedure employs a precise calibration against molecular scattering in the mid-stratosphere. The 1064 nm channel detection employs a high-speed analog APD for surface and atmospheric measurements where the detection sensitivity is limited by detector noise and is over an order of magnitude less than at 532 nm. A unique feature of

  6. Urban increments of gaseous and aerosol pollutants and their sources using mobile aerosol mass spectrometry measurements

    NASA Astrophysics Data System (ADS)

    Elser, Miriam; Bozzetti, Carlo; El-Haddad, Imad; Maasikmets, Marek; Teinemaa, Erik; Richter, Rene; Wolf, Robert; Slowik, Jay G.; Baltensperger, Urs; Prévôt, André S. H.

    2016-06-01

    Air pollution is one of the main environmental concerns in urban areas, where anthropogenic emissions strongly affect air quality. This work presents the first spatially resolved detailed characterization of PM2.5 (particulate matter with aerodynamic equivalent diameter daero ≤ 2.5 µm) in two major Estonian cities, Tallinn and Tartu. The measurements were performed in March 2014 using a mobile platform. In both cities, the non-refractory (NR)-PM2.5 was characterized by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) using a recently developed lens which increases the transmission of super-micron particles. Equivalent black carbon (eBC) and several trace gases including carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) were also measured. The chemical composition of PM2.5 was found to be very similar in the two cities. Organic aerosol (OA) constituted the largest fraction, explaining on average about 52 to 60 % of the PM2.5 mass. Four sources of OA were identified using positive matrix factorization (PMF): hydrocarbon-like OA (HOA, from traffic emissions), biomass burning OA (BBOA, from biomass combustion), residential influenced OA (RIOA, probably mostly from cooking processes with possible contributions from waste and coal burning), and oxygenated OA (OOA, related to secondary aerosol formation). OOA was the major OA source during nighttime, explaining on average half of the OA mass, while during daytime mobile measurements the OA was affected by point sources and dominated by the primary fraction. A strong increase in the secondary organic and inorganic components was observed during periods with transport of air masses from northern Germany, while the primary local emissions accumulated during periods with temperature inversions. Mobile measurements offered the identification of different source regions within the urban areas and the assessment of the extent to which pollutants concentrations exceeded regional background

  7. Aerosol characterization and transport pathway using ground-based measurement and space borne remote sensing

    NASA Astrophysics Data System (ADS)

    Boyouk, Neda; Léon, Jean-François; Delbarre, Hervé

    2008-10-01

    Using two years measurements of aerosol extinction coefficient retrieval from CALIPSO as a joint NASA-CNES satellite mission along with ground-based measurements of particle mass concentration (PM2.5), we assess particulate matter air quality over different urban and periurban areas in France. In order to understanding the influence of the long range transport onto the local aerosol load we have focused on analysing of pollution event in Lille - urban area and Dunkerque - industrial area. We compared ground- based measurements with CALIPSO measurements. The CALIPSO level 2 aerosol records are more useful because the extinction coefficient is available. We use the extinction coefficient profiles which are provided by CALIPSO to depict the vertical structure of the aerosol properties. The combination of ground- based measurements of PM2.5, aerosol optical thickness (AOT's) obtained by Aeronet network data and CALIOP data enhances the possibilities of studying transport pathway of aerosol in the atmosphere and aerosol optical properties (aerosol extinction coefficient, aerosol optical depth, atmosphere transparency). The linear relationship between AOT _CALIPSO and AOT _ Aeronet network shows a slop of 0.4 in north of France. Moreover, we observed the good relationship between PM2.5 and AOT by CALIPSO profiles with a slope of 57.59 and correlation coefficient of 0.75 over France.

  8. Airborne measurements of spectral direct aerosol radiative forcing in INTEX/ICARTT (2004) and comparisons to previous campaigns

    NASA Astrophysics Data System (ADS)

    Redemann, J.; Pilewskie, P.; Russell, P.; Livingston, J.; Howard, S.; Schmid, B.; Pommier, J.; Gore, W.; Eilers, J.; Wendisch, M.; Bush, B.; Valero, F.

    2005-12-01

    As part of the INTEX-NA (INtercontinental chemical Transport EXperiment-North America) and ITCT (Intercontinental Transport and Chemical Transformation of anthropogenic pollution) field studies, the NASA Ames 14-channel Airborne Tracking Sunphotometer (AATS-14) and a pair of Solar Spectral Flux Radiometers (SSFR) took measurements from aboard a Jetstream 31 (J31) aircraft during 19 science flights (~ 53 flight hours) over the Gulf of Maine between 12 July and 8 August 2004. AATS-14 measures the direct solar beam transmission at 14 discrete wavelengths (354-2138 nm), yielding aerosol optical depth (AOD) spectra, while the SSFR system yields down- and upwelling solar irradiance at a spectral resolution of ~ 8-12 nm over the wavelength range 300-1700 nm. The combination of simultaneous AATS and SSFR measurements yields plots of net spectral irradiance as a function of aerosol optical depth as measured along horizontal flight legs. From the slope of these plots we determine the instantaneous aerosol-induced change in net radiative flux per change in AOD. By normalization to an aerosol optical depth change of unity we derive the spectral aerosol radiative forcing efficiency [W m-2 nm-1]. Numerical integration of the irradiance measurements over a given spectral range yields the broadband aerosol radiative forcing efficiency [W m-2]. In INTEX/ITCT, we observed a total of 16 horizontal AOD gradients, with 10 gradients well suited for our analysis because of the small changes in solar zenith angle. Within the 10 case studies we found a high variability in the derived instantaneous aerosol forcing efficiencies for the visible wavelength range (350-700 nm), with a mean of -79.6 W m-2 and a standard deviation of 21.8 W m-2 (27%). The mean instantaneous forcing efficiency for the visible plus near-IR wavelength range (350-1670 nm) was derived to be 135.3 W m-2 with a standard deviation of 36.0 W m-2 (27%). An analytical conversion of the instantaneous forcing efficiencies to

  9. Hygroscopic Measurements of Aerosol Particles in the San Joaquin Valley California during the DRAGON and Discover AQ Campaign 2013

    NASA Astrophysics Data System (ADS)

    Orozco, D.; Delgado, R.; Hoff, R. M.

    2013-12-01

    In the ambient atmosphere, aerosol particles experience hygroscopic growth due to the influence of relative humidity (RH). Wet aerosols particles are larger than their dry equivalents, therefore they scatter more light. Quantitative knowledge of the RH effect and its influence on the light scattering coefficient on aerosol particles is of substantial importance when comparing ground based observations with other optical aerosol measurements techniques such satellite and sunphotometric retrievals of aerosol optical depth. The DISCOVER-AQ campaign is focused in improving the interpretation and relation between satellite observations and surface conditions related to air quality. In the winter of 2013, this campaign was held in the San Joaquin Valley, California, where systematic and concurrent observations of column integrated surface, and vertically resolved distributions of aerosols and trace gases relevant to air quality and their evolution during the day were observed. Different instruments such as particulate samplers, lidars, meteorological stations and airborne passive and active monitoring were coordinated to measure the aerosol structure of the San Joaquin Valley in a simultaneous fashion. A novel humidifier-dryer system for a TSI 3563 Nephelometer was implemented in the Penn State University NATIVE trailer located in Porterville California in order to measure the scattering coefficient σsp(λ) at three different wavelengths (λ=440, 550 and 700nm) in a RH range from 30 to 95%. The system was assembled by combining Nafion tubes to humidify and dry the aerosols and stepping motor valves to control the flow and the amount of humidity entering to the Nephelometer. Measurements in Porterville California reached dry scattering coefficient readings greater than 300Mm-1 at 550nm indicating the presence of a large amount of particles in the region. However, the ratio between scattering coefficients at high and low humidity, called the enhancement factor f

  10. Urban organic aerosols measured by single particle mass spectrometry in the megacity of London

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Harrison, R. M.

    2011-02-01

    During the month of October 2006, as part of the REPARTEE-I experiment (Regent's Park and Tower Environmental Experiment) an Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed at an urban background location in the city of London, UK. Fifteen particle types were classified, some of which were accompanied by Aerosol Mass Spectrometer (AMS) quantitative aerosol mass loading measurements (Dall'Osto et al., 2009a, b). In this manuscript the origins and properties of four particle types associated with locally generated aerosols, independent of the air mass type advected into London, are examined. One particle type, originating from lubricating oil (referred to as Ca-EC), was associated with morning rush hour traffic emissions. A second particle type, composed of both inorganic and organic species (called Na-EC-OC), was found enhanced in particle number concentration during evening time periods, and is likely to originate from a source operating at this time of day, or more probably from condensation of semi-volatile species, and contains both primary and secondary components. A third class, internally mixed with organic carbon and sulphate (called OC), was found to spike both in the morning and evenings. The fourth class (SOA-PAH) exhibited maximum frequency during the warmest part of the day, and a number of factors point towards secondary production from traffic-related volatile aromatic compounds. Single particle mass spectra of this particle type showed an oxidized polycyclic aromatic compound signature. Finally, a comparison of ATOFMS particle class data is made with factors obtained by Positive Matrix Factorization from AMS data.. Both the Ca-EC and OC particle types correlate with the AMS HOA primary organic fraction (R2 = 0.65 and 0.50 respectively), and Na-EC-OC, but not SOA-PAH, which correlates weakly with the AMS OOA secondary organic aerosol factor (R2 = 0.35). A detailed analysis was conducted to identify ATOFMS particle type(s) representative

  11. In situ airborne measurements of aerosol optical properties during photochemical pollution events

    NASA Astrophysics Data System (ADS)

    Mallet, M.; van Dingenen, R.; Roger, J. C.; Despiau, S.; Cachier, H.

    2005-02-01

    Dry aerosol optical properties (scattering, absorbing coefficients, and single scattering albedo) were derived from in situ airborne measurements during two photochemical pollution events (25 and 26 June) observed during the Experience sur Site pour Contraindre les Modeles de Pollution atmospherique et de Transport d'Emissions (ESCOMPTE) experiment. Two flights were carried out during daytime (one during the morning and one at noon) over a domain, allowing the investigation of how an air pollution event affects the particle optical properties. Both horizontal distribution and vertical profiles are presented. Results from the horizontal mapping show that plumes of enhanced scattering and absorption are formed in the planetary boundary layer (PBL) during the day in the sea breeze-driven outflow of the coastal urban-industrial area of Marseille-Fos de Berre. The domain-averaged scattering coefficient (at 550 nm) over land σs changes from 35 (28) Mm-1 during land breeze to 63 (43) Mm-1 during sea breeze on 25 June (26 June), with local maxima reaching > 100 Mm-1. The increase in the scattering coefficient is associated with new particle formation, indicative of secondary aerosol formation. Simultaneously, the domain-averaged absorption coefficient increases from 5.6 (3.4) Mm-1 to 9.3 (8.0) Mm-1. The pollution plume leads to strong gradients in the single scattering albedo ωo over the domain studied, with local values as low as 0.73 observed inside the pollution plume. The role of photochemistry and secondary aerosol formation during the 25 June case is shown to increase ωo and to make the aerosol more `reflecting' while the plume moves away from the sources. The lower photochemical activity, observed in the 26 June case, induces a relatively higher contribution of black carbon, making the aerosol more absorbing. Results from vertical profiles at a single near-urban location in the domain indicate that the changes in optical properties happen almost entirely within

  12. 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

  13. Application of Microwave Analog Measurements to the Modeling of Titan's Aerosols

    NASA Astrophysics Data System (ADS)

    Thomas-Osip, J. E.; Gustafson, B. Å. S.; Kolokolova, L.; Xu, Y.-l.

    2001-11-01

    A combination of laboratory experiments, theoretical modeling, and spacecraft in situ observations is employed to characterize the aerosols in the atmosphere of Titan. The scattering properties of model aerosols were measured using the Microwave Analog Light Scattering Facility at the University of Florida and complemented with theoretical modeling of radiative transfer in Titan's atmosphere. This study compares these modeling results with photopolarimetric observations made over a range of phase angles by the Pioneer 11 and Voyagers 1 and 2 spacecraft. Important results of this work include a survey of the scattering properties of different particle morphologies and compositions necessary to accurately interpret these observations without introducing non-physical assumptions about the particles or requiring additional free parameters to the radiative transfer models. Previous studies use calculation methods which, due to computing memory and processing time requirements, a priori exclude many particle shapes and sizes that the microwave analog laboratory is ideal for exploring. The goal of the present work, to directly constrain aerosol physical characteristics, is addressed by studying in a consistent manner how a variety of aerosol characteristics affect the polarization and intensity reflected by Titan's atmosphere. Model results for many particle morphologies do not match the in situ spacecraft observations. The most plausible physical particle models suggest that a combination of Rayleigh-like single particles and aggregates that are larger than those previously suggested and investigated (Rannou et al. 1997, JGR, 102, 10997; West & Smith 1991, Icarus, 90, 330) provide the best fit to the existing data. Additional laboratory experiments and more refined modeling awaits the results of a new rich observational dataset following the Cassini/Huygens encounter with Titan in 2004. This work was partially funded by the NASA GSRP.

  14. Ground-based aerosol measurements during CHARMEX/ADRIMED campaign at Granada station

    NASA Astrophysics Data System (ADS)

    Granados-Muñoz, Maria Jose; Bravo-Aranda, Juan Antonio; Navas-Guzman, Francisco; Guerro-Rascado, Juan Luis; Titos, Gloria; Lyamani, Hassan; Valenzuela, Antonio; Cazorla, Alberto; Olmo, Francisco Jose; Mallet, Marc; Alados-Arboledas, Lucas

    2015-04-01

    In the framework of ChArMEx/ADRIMED (Chemistry-Aerosol Mediterranean Experiment, http://charmex.lsce.ipsl.fr/; Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) projects, a field experiment based on in situ and remote sensing measurements from surface and airborne platforms was performed. The ADRIMED project aimed to capture the high complexity of the Mediterranean region by using an integrated approach based on intensive experimental field campaign and spaceborne observations, radiative transfer calculations and climate modelling with Regional Climate Models better adapted than global circulation models. For this purpose, measurements were performed at different surface super-sites (including Granada station) over the Occidental Mediterranean region during summer 2013 for creating an updated database of the physical, chemical, optical properties and the vertical distribution of the major "Mediterranean aerosols". Namely, measurements at Granada station were performed on 16 and 17 July 2013, in coincidence with the overpasses of the ATR aircraft over the station. The instrumentation used for the campaign includes both remote sensing instruments (a multiwavelength Raman lidar and a sun photometer) and in-situ measurements (a nephelometer, a Multi-Angle Absorption Photometer (MAAP), an Aerodynamic particle sizer (APS), a high volume sampler of PM10 and an aethalometer). During the measurement period a mineral dust event was detected, with similar dust load on both days. According to in-situ measurements, the event reached the surface level on 16 of June. Vertically resolved lidar measurements indicated presence of mineral dust layers up to 5 km asl both on 16 and 17 June 2013. Temporal evolution analysis indicated that on 17 June the dust layer decoupled from the boundary layer and disappeared around 14:00 UTC. In addition, lidar and sun-photometer data were used to retrieve volume concentration profiles by means of LIRIC (Lidar

  15. Design And Performance Of The Stratospheric Aerosol And Gas Experiment II (SAGE II) Instrument

    NASA Astrophysics Data System (ADS)

    Zaun, N. H.; Mauldin, L. E.; McCormick, M. P.

    1984-01-01

    Design and performance data are presented for the Stratospheric Aerosol and Gas Experi-ment II (SAGE II) instrument, which has been developed for the Earth Radiation Budget Satellite (ERBS). SAGE II is designed to monitor globally the vertical distribution of strato-spheric aerosols, ozone, water vapor and nitrogen dioxide by measuring the extinction of solar radiation through the earth's atmosphere during the ERBS observatory solar occultations. Solar radiation is reflected from a flat scanning mirror into a Cassegrain type telescope, which forms a solar image on the entrance slit of a grating spectrometer. The SAGE II instantaneous-field-of-view (IFOV) is scanned along the vertical solar diameter by the elevation scan mirror. The entire optical system is contained within an azimuth gimbal which tracks the solar radiometric centroid during the data event. This spectrometer, with help from three interference filters, isolates seven spectral wavelengths ranging from 0.385 micrometers to 1.02 micrometers. All seven channels use silicon photodiode detectors oper-ated in the photovoltaic mode. Detector outputs are multiplexed into a serial data stream for readout by the ERBS telemetry system. Each output is sampled 64 times per second and digitized to 12 bit resolution. SAGE II is a third generation instrument following the highly successful SAM II and SAGE programs.

  16. Long Term Stratospheric Aerosol Lidar Measurements in Kyushu

    NASA Technical Reports Server (NTRS)

    Fujiwara, Motowo

    1992-01-01

    Lidar soundings of the stratospheric aerosols have been made since 1972 at Fukuoka, Kyushu Island of Japan. Volcanic clouds from eruptions of La Soufriere, Sierra Negra, St. Helens, Uluwan, Alaid, unknown volcano, and El Chichon were detected one after another in only three years from 1979 to 1982. In july 1991 strong scattering layers which were originated from the serious eruptions of Pinatubo in June and were almost comparable to the El Chichon clouds were detected. Volcanic clouds from pinatubo and other volcanos mentioned are examined and carefully compared to each other and to the wind and temperature which was measured by Fukuoka Meteorological Observatory almost at the same time as the lidar observation was made.

  17. Aerosol Profile Measurements from the NASA Langley Research Center Airborne High Spectral Resolution Lidar

    NASA Technical Reports Server (NTRS)

    Obland, Michael D.; Hostetler, Chris A.; Ferrare, Richard A.; Hair, John W.; Roers, Raymond R.; Burton, Sharon P.; Cook, Anthony L.; Harper, David B.

    2008-01-01

    Since achieving first light in December of 2005, the NASA Langley Research Center (LaRC) Airborne High Spectral Resolution Lidar (HSRL) has been involved in seven field campaigns, accumulating over 450 hours of science data across more than 120 flights. Data from the instrument have been used in a variety of studies including validation and comparison with the Cloud- Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite mission, aerosol property retrievals combining passive and active instrument measurements, aerosol type identification, aerosol-cloud interactions, and cloud top and planetary boundary layer (PBL) height determinations. Measurements and lessons learned from the HSRL are leading towards next-generation HSRL instrument designs that will enable even further studies of aerosol intensive and extensive parameters and the effects of aerosols on the climate system. This paper will highlight several of the areas in which the NASA Airborne HSRL is making contributions to climate science.

  18. Near-highway aerosol and gas-phase measurements in a high-diesel environment

    NASA Astrophysics Data System (ADS)

    DeWitt, H. L.; Hellebust, S.; Temime-Roussel, B.; Ravier, S.; Polo, L.; Jacob, V.; Buisson, C.; Charron, A.; André, M.; Pasquier, A.; Besombes, J. L.; Jaffrezo, J. L.; Wortham, H.; Marchand, N.

    2015-04-01

    Diesel-powered passenger cars currently outnumber gasoline-powered cars in many countries, particularly in Europe. In France, diesel cars represented 61% of light duty vehicles in 2011 and this percentage is still increasing (French Environment and Energy Management Agency, ADEME). As part of the September 2011 joint PM-DRIVE (Particulate Matter - DiRect and Indirect on-road Vehicular Emissions) and MOCOPO (Measuring and mOdeling traffic COngestion and POllution) field campaign, the concentration and high-resolution chemical composition of aerosols and volatile organic carbon species were measured adjacent to a major urban highway south of Grenoble, France. Alongside these atmospheric measurements, detailed traffic data were collected from nearby traffic cameras and loop detectors, which allowed the vehicle type, traffic concentration, and traffic speed to be quantified. Six aerosol age and source profiles were resolved using the positive matrix factorization model on real-time high-resolution aerosol mass spectra. These six aerosol source/age categories included a hydrocarbon-like organic aerosol (HOA) commonly associated with primary vehicular emissions, a nitrogen-containing aerosol with a diurnal pattern similar to that of HOA, oxidized organic aerosol (OOA), and biomass burning aerosol. While quantitatively separating the influence of diesel from that of gasoline proved impossible, a low HOA : black carbon ratio, similar to that measured in other high-diesel environments, and high levels of NOx, also indicative of diesel emissions, were observed. Although the measurement site was located next to a large source of primary emissions, which are typically found to have low oxygen incorporation, OOA was found to comprise the majority of the measured organic aerosol, and isotopic analysis showed that the measured OOA contained mainly modern carbon, not fossil-derived carbon. Thus, even in this heavily vehicular-emission-impacted environment, photochemical processes

  19. Disability Experience and Measurement.

    PubMed

    Verbrugge, Lois M

    2016-10-01

    Top themes of international research on disability in the past three decades are discussed: disability dynamics, buffers and barriers for disability, disability trends, and disability among very old persons. Each theme is highlighted by research examples. Turning to measurement, I discuss traditional measures of disability, new longer and shorter ones, and composites like disability-free life expectancy, noting their merits. Contemporary models of disability are presented, ranging from visual images to formal theories. The article ends on how scientists can facilitate movement of disability science into health care practice and policy.

  20. Measurement of elemental concentration of aerosols using spark emission spectroscopy.

    PubMed

    Diwakar, Prasoon K; Kulkarni, Pramod

    A coaxial microelectrode system has been used to collect and analyse the elemental composition of aerosol particles in near real-time using spark emission spectroscopy. The technique involves focused electrostatic deposition of charged aerosol particles onto the flat tip of a microelectrode, followed by introduction of spark discharge. A pulsed spark discharge was generated across the electrodes with input energy ranging from 50 to 300 mJ per pulse, resulting in the formation of controlled pulsed plasma. The particulate matter on the cathode tip is ablated and atomized by the spark plasma, resulting in atomic emissions which are subsequently recorded using a broadband optical spectrometer for element identification and quantification. The plasma characteristics were found to be very consistent and reproducible even after several thousands of spark discharges using the same electrode system. The spark plasma was characterized by measuring the excitation temperature (~7000 to 10 000 K), electron density (~10(16) cm(-3)), and evolution of spectral responses as a function of time. The system was calibrated using particles containing Pb, Si, Na and Cr. Absolute mass detection limits in the range 11 pg to 1.75 ng were obtained. Repeatability of spectral measurements varied from 2 to 15%. The technique offers key advantages over similar microplasma-based techniques such as laser-induced breakdown spectroscopy, as: (i) it does not require any laser beam optics and eliminates any need for beam alignment, (ii) pulse energy from dc power supply in SIBS system can be much higher compared to that from laser source of the same physical size, and (iii) it is quite conducive to compact, field-portable instrumentation.

  1. Measurement of elemental concentration of aerosols using spark emission spectroscopy†

    PubMed Central

    Diwakar, Prasoon K.

    2015-01-01

    A coaxial microelectrode system has been used to collect and analyse the elemental composition of aerosol particles in near real-time using spark emission spectroscopy. The technique involves focused electrostatic deposition of charged aerosol particles onto the flat tip of a microelectrode, followed by introduction of spark discharge. A pulsed spark discharge was generated across the electrodes with input energy ranging from 50 to 300 mJ per pulse, resulting in the formation of controlled pulsed plasma. The particulate matter on the cathode tip is ablated and atomized by the spark plasma, resulting in atomic emissions which are subsequently recorded using a broadband optical spectrometer for element identification and quantification. The plasma characteristics were found to be very consistent and reproducible even after several thousands of spark discharges using the same electrode system. The spark plasma was characterized by measuring the excitation temperature (~7000 to 10 000 K), electron density (~1016 cm−3), and evolution of spectral responses as a function of time. The system was calibrated using particles containing Pb, Si, Na and Cr. Absolute mass detection limits in the range 11 pg to 1.75 ng were obtained. Repeatability of spectral measurements varied from 2 to 15%. The technique offers key advantages over similar microplasma-based techniques such as laser-induced breakdown spectroscopy, as: (i) it does not require any laser beam optics and eliminates any need for beam alignment, (ii) pulse energy from dc power supply in SIBS system can be much higher compared to that from laser source of the same physical size, and (iii) it is quite conducive to compact, field-portable instrumentation. PMID:26491209

  2. Evolution of biomass burning aerosol over the Amazon: airborne measurements of aerosol chemical composition, microphysical properties, mixing state and optical properties during SAMBBA

    NASA Astrophysics Data System (ADS)

    Morgan, W.; Allan, J. D.; Flynn, M.; Darbyshire, E.; Hodgson, A.; Liu, D.; O'Shea, S.; Bauguitte, S.; Szpek, K.; Johnson, B.; Haywood, J.; Longo, K.; Artaxo, P.; Coe, H.

    2013-12-01

    Biomass burning represents one of the largest sources of particulate matter to the atmosphere, resulting in a significant perturbation to the Earth's radiative balance coupled with serious impacts on public health. On regional scales, the impacts are substantial, particularly in areas such as the Amazon Basin where large, intense and frequent burning occurs on an annual basis for several months. Absorption by atmospheric aerosols is underestimated by models over South America, which points to significant uncertainties relating to Black Carbon (BC) aerosol properties. Initial results from the South American Biomass Burning Analysis (SAMBBA) field experiment, which took place during September and October 2012 over Brazil on-board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft, are presented here. Aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and a DMT Single Particle Soot Photometer (SP2). The physical, chemical and optical properties of the aerosols across the region will be characterized in order to establish the impact of biomass burning on regional air quality, weather and climate. The aircraft sampled a range of conditions including sampling of pristine Rainforest, fresh biomass burning plumes, regional haze and elevated biomass burning layers within the free troposphere. The aircraft sampled biomass burning aerosol across the southern Amazon in the states of Rondonia and Mato Grosso, as well as in a Cerrado (Savannah-like) region in Tocantins state. This presented a range of fire conditions, in terms of their number, intensity, vegetation-type and their combustion efficiencies. Near-source sampling of fires in Rainforest environments suggested that smouldering combustion dominated, while flaming combustion dominated in the Cerrado. This led to significant differences in aerosol chemical composition, particularly in terms of the BC content, with BC being enhanced in the Cerrado

  3. 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

  4. 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.

  5. SAM II aerosol profile measurements, Poker Flat, Alaska; July 16-19, 1979

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Chu, W. P.; Mcmaster, L. R.; Grams, G. W.; Herman, B. M.; Pepin, T. J.; Russell, P. B.; Swissler, T. J.

    1981-01-01

    SAM II satellite measurements during the July 1979 Poker Flat mission, yielded an aerosol extinction coefficient of 0.0004/km at 1.0 micron wavelength, in the region of the stratospheric aerosol mixing ratio peak (12-16 km). The stratospheric aerosol optical depth for these data, calculated from the tropopause through 30 km, is approximately 0.001. These results are consistent with the average 1979 summertime values found throughout the Arctic.

  6. Estimation of Aerosol Direct Radiative Effects from Satellite and In Situ Measurements

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.; Russell, Philip B.; Schmid, Beat; Redemann, Jens; McIntosh, Dawn

    2000-01-01

    Ames researchers have combined measurements from satellite, aircraft, and the surface to estimate the effect of airborne particles (aerosols) on the solar radiation over the North Atlantic region. These aerosols (which come from both natural and pollution sources) can reflect solar radiation, causing a cooling effect that opposes the warming caused by carbon dioxide. Recently, increased attention has been paid to aerosol effects to better understand the Earth climate system.

  7. Measurements of trace gas species and aerosols at three Siberian stations

    NASA Astrophysics Data System (ADS)

    Arshinov, Mikhail Yu.; Belan, Boris D.; Davydov, Denis K.; Kozlov, Artem V.; Ivlev, Georgii A.; Pestunov, Dmitrii A.; Tolmachev, Gennadii N.; Fofonov, Alexander V.

    2014-05-01

    Siberia is of great importance to understand the climate change due to it covers about 10% of Earth's land surface and it has the largest area to be studied under the Pan-Eurasian Experiment (PEEX). In the overview done by Kulmala et al. (2011) authors arrived at a conclusion that continuous and comprehensive measurements of GHGs and aerosols over Siberia are still lacking. Understanding the importance of this problem, in recent years the Institute of Atmospheric Optics SB RAS established several monitoring stations for continuous measurements of aerosol and trace gas species to fill up this gap. In this paper we present some results of continuous measurements of trace gas species and aerosols carried out at three stations located in West Siberia. The first one is a so-called TOR-station located in the scientific campus of Tomsk (56° 28'41"N, 85° 03'15"E), the second one is the Base Experimental Complex (BEC, 56° 28'49"N, 85° 06'08"E) - in the eastern suburbs of Tomsk, and the third one is Fonovaya Observatory (56° 25'07"N, 84° 04'27"E) - in a rural area 60 km west of Tomsk. All equipment of the stations is fully automated and can be monitored via Internet. Gas analyzers are hourly calibrated against standard gas mixtures, micro-flux gas sources, or gas generators, depending on the instrument type and the gas to be detected. Aerosol measurements carried out continuously from March 2010 enabled a frequency and seasonal dependency of the new particle formation (NPF) events to be revealed. NPF events in Siberia are more often observed during spring (from March to May) and early autumn (secondary frequency peak in September). On average, NPF evens took place on 23-28 % of all days. This work was funded by Presidium of RAS (Program No. 4), Brunch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5), Interdisciplinary integration projects of Siberian Branch of RAS (No. 35, No. 70, No. 131), Russian Foundation for Basic Research (grants No 14

  8. 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

  9. 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

  10. Spectrally-resolved measurements of aerosol extinction at ultraviolet and visible wavelengths

    NASA Astrophysics Data System (ADS)

    Flores, M.; Washenfelder, R. A.; Brock, C. A.; Brown, S. S.; Rudich, Y.

    2012-12-01

    Aerosols play an important role in the Earth's radiative budget. Aerosol extinction includes both the scattering and absorption of light, and these vary with wavelength, aerosol diameter, and aerosol composition. Historically, aerosol absorption has been measured using filter-based or extraction methods that are prone to artifacts. There have been few investigations of ambient aerosol optical properties at the blue end of the visible spectrum and into the ultraviolet. Brown carbon is particularly important in this spectral region, because it both absorbs and scatters light, and encompasses a large and variable group of organic compounds from biomass burning and secondary organic aerosol. We have developed a laboratory instrument that combines new, high-power LED light sources with high-finesse optical cavities to achieve sensitive measurements of aerosol optical extinction. This instrument contains two broadband channels, with spectral coverage from 360 - 390 nm and 385 - 420 nm. Using this instrument, we report aerosol extinction in the ultraviolet and near-visible spectral region as a function of chemical composition and structure. We have measured the extinction cross-sections between 360 - 420 nm with 0.5 nm resolution using different sizes and concentrations of polystyrene latex spheres, ammonium sulfate, and Suwannee River fulvic acid. Fitting the real and imaginary part of the refractive index allows the absorption and scattering to be determined.

  11. Measurement of the nucleation of atmospheric aerosol particles.

    PubMed

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

    2012-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-11-01

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

  13. Evaluation of LIDAR/Polarimeter Aerosol Measurements by In Situ Instrumentation during DEVOTE

    NASA Astrophysics Data System (ADS)

    Beyersdorf, A. J.; Ziemba, L. D.; Anderson, B. E.; Dolgos, G.; Ottaviani, M.; Obland, M. D.; Rogers, R.; Thornhill, K. L.; Winstead, E. L.; Yang, M. M.; Hair, J. W.

    2011-12-01

    Combined measurements from LIDAR (LIght Detection And Ranging) and polarimeter instruments provide the opportunity for enhanced satellite observations of aerosol properties including retrievals of aerosol optical depth, single scattering albedo, effective radius, and refractive index. However, these retrievals (specifically for refractive index) have not been fully vetted and require additional intercomparisons with in situ measurements to improve accuracy. Proper validation of these combined LIDAR/polarimeter retrievals requires evaluation in varying atmospheric conditions and of varying aerosol composition. As part of this effort, two NASA Langley King Air aircraft have been outfitted to provide coordinated measurements of aerosol properties. One will be used as a remote sensing platform with the NASA Langley high-spectral resolution LIDAR (HSRL) and NASA GISS research scanning polarimeter (RSP). The second aircraft has been modified for use as an in situ platform and will house a suite of aerosol microphysical instrumentation, a pair of diode laser hygrometers (DLHs) for water vapor and cloud extinction measurements, and a polarized imaging nephelometer (PI-Neph). The remote sensing package has flown in a variety of campaigns, however only rarely has been able to coordinate with in situ measurements. The use of two collocated aircraft will allow for future coordinated flights to provide a more complete dataset for evaluation of aerosol retrievals and allow for fast-response capability. Results from the first coordinated King Air flights as part of DEVOTE (Development and Evaulation of satellite ValidatiOn Tools by Experimenters) will be presented. Flights are planned out of Hampton, VA during September and October 2011 including underflights of the CALIPSO satellite and overflights of ground-based AERONET (AErosol RObotic NETwork) sites. These will provide a comparison of aerosol properties between in situ and remote instruments (ground, aircraft, and satellite

  14. Gamma Astrometric Measurement Experiment

    NASA Astrophysics Data System (ADS)

    Gai, M.; Lattanzi, M. G.; Ligori, S.; Loreggia, D.; Vecchiato, A.

    GAME aims at the measurement of gravitational deflection of the light by the Sun, by an optimised telescope on board a small class satellite. The targeted precision on the gamma parameter of the Parametrised Post-Newtonian formulation of General Relativity is below 10-6, i.e. one to two orders of magnitude better than the best current results. Such precision is suitable to detect possible deviations from the unity value, associated to generalised Einstein models for gravitation, with potentially huge impacts on the cosmological distribution of dark matter and dark energy. The measurement principle is based on differential astrometry. The observations also allow additional scientific objectives related to tests of General Relativity and to the study of exo-planetary systems. The instrument concept is based on a dual field, multiple aperture Fizeau interferometer, observing simultaneously two regions close to the Solar limb. The diluted optics achieves efficient rejection of the solar radiation, with good angular resolution on the science targets. We describe the science motivation, the proposed mission implementation and the expected performance.

  15. Retrieval of Aerosol information from UV measurement by using optimal estimation method

    NASA Astrophysics Data System (ADS)

    KIM, M.; Kim, J.; Jeong, U.; Kim, W. V.; Kim, S. K.; Lee, S. D.; Moon, K. J.

    2014-12-01

    An algorithm to retrieve aerosol optical depth (AOD), single scattering albedo (SSA), and aerosol loading height is developed for GEMS (Geostationary Environment Monitoring Spectrometer) measurement. The GEMS is planned to be launched in geostationary orbit in 2018, and employs hyper-spectral imaging with 0.6 nm resolution to observe solar backscatter radiation in the UV and Visible range. In the UV range, the low surface contribution to the backscattered radiation and strong interaction between aerosol absorption and molecular scattering can be advantageous in retrieving aerosol information such as AOD and SSA [Torres et al., 2007; Torres et al., 2013; Ahn et al., 2014]. However, the large contribution of atmospheric scattering results in the increase of the sensitivity of the backward radiance to aerosol loading height. Thus, the assumption of aerosol loading height becomes important issue to obtain accurate result. Accordingly, this study focused on the simultaneous retrieval of aerosol loading height with AOD and SSA by utilizing the optimal estimation method. For the RTM simulation, the aerosol optical properties were analyzed from AERONET inversion data (level 2.0) at 46 AERONET sites over ASIA. Also, 2-channel inversion method is applied to estimate a priori value of the aerosol information to solve the Lavenberg Marquardt equation. The GEMS aerosol algorithm is tested with OMI level-1B dataset, a provisional data for GEMS measurement, and the result is compared with OMI standard aerosol product and AERONET values. The retrieved AOD and SSA show reasonable distribution compared with OMI products, and are well correlated with the value measured from AERONET. However, retrieval uncertainty in aerosol loading height is relatively larger than other results.

  16. Aerosol, Cloud and Trace Gas Observations Derived from Airborne Hyperspectral Radiance and Direct Beam Measurements in Recent Field Campaigns

    NASA Technical Reports Server (NTRS)

    Redemann, J.; Flynn, C. J.; Shinozuka, Y.; Kacenelenbogen, M.; Segal-Rosenheimer, M.; LeBlanc, S.; Russell, P. B.; Livingston, J. M.; Schmid, B.; Dunagan, S. E.; Johnson, R. R.

    2014-01-01

    The AERONET (AErosol RObotic NETwork) ground-based suite of sunphotometers provides measurements of spectral aerosol optical depth (AOD), precipitable water and spectral sky radiance, which can be inverted to retrieve aerosol microphysical properties that are critical to assessments of aerosol-climate interactions. Because of data quality criteria and sampling constraints, there are significant limitations to the temporal and spatial coverage of AERONET data and their representativeness for global aerosol conditions. The 4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research) instrument, jointly developed by NASA Ames and PNNL with NASA Goddard collaboration, combines airborne sun tracking and AERONET-like sky scanning with spectroscopic detection. Being an airborne instrument, 4STAR has the potential to fill gaps in the AERONET data set. Dunagan et al. [2013] present results establishing the performance of the instrument, along with calibration, engineering flight test, and preliminary scientific field data. The 4STAR instrument operated successfully in the SEAC4RS [Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys] experiment in Aug./Sep. 2013 aboard the NASA DC-8 and in the DoE [Department of Energy]-sponsored TCAP [Two Column Aerosol Project, July 2012 & Feb. 2013] experiment aboard the DoE G-1 aircraft (Shinozuka et al., 2013), and acquired a wealth of data in support of mission objectives on all SEAC4RS and TCAP research flights. 4STAR provided direct beam measurements of hyperspectral AOD, columnar trace gas retrievals (H2O, O3, NO2; Segal-Rosenheimer et al., 2014), and the first ever airborne hyperspectral sky radiance scans, which can be inverted to yield the same products as AERONET ground-based observations. In addition, 4STAR measured zenith radiances underneath cloud decks for retrievals of cloud optical depth and effective diameter. In this presentation, we provide an overview of the new

  17. Size Resolved Measurements of Springtime Aerosol Particles over the Northern South China Sea

    NASA Technical Reports Server (NTRS)

    Atwood, Samuel A.; Reid, Jeffrey S.; Kreidenweis, Sonia M.; Cliff, Stephen S.; Zhao, Yongjing; Lin, Neng-Huei; Tsay, Si-Chee; Chu, Yu-Chi; Westphal, Douglas L.

    2012-01-01

    Large sources of aerosol particles and their precursors are ubiquitous in East Asia. Such sources are known to impact the South China Sea (henceforth SCS), a sometimes heavily polluted region that has been suggested as particularly vulnerable to climate change. To help elucidate springtime aerosol transport into the SCS, an intensive study was performed on the remote Dongsha (aka Pratas) Islands Atoll in spring 2010. As part of this deployment, a Davis Rotating-drum Uniform size-cut Monitor (DRUM) cascade impactor was deployed to collect size-resolved aerosol samples at the surface that were analyzed by X-ray fluorescence for concentrations of selected elements. HYSPLIT backtrajectories indicated that the transport of aerosol observed at the surface at Dongsha was occurring primarily from regions generally to the north and east. This observation was consistent with the apparent persistence of pollution and dust aerosol, along with sea salt, in the ground-based dataset. In contrast to the sea-level observations, modeled aerosol transport suggested that the westerly flow aloft (w700 hPa) transported smoke-laden air toward the site from regions from the south and west. Measured aerosol optical depth at the site was highest during time periods of modeled heavy smoke loadings aloft. These periods did not coincide with elevated aerosol concentrations at the surface, although the model suggested sporadic mixing of this free-tropospheric aerosol to the surface over the SCS. A biomass burning signature was not clearly identified in the surface aerosol composition data, consistent with this aerosol type remaining primarily aloft and not mixing strongly to the surface during the study. Significant vertical wind shear in the region also supports the idea that different source regions lead to varying aerosol impacts in different vertical layers, and suggests the potential for considerable vertical inhomogeneity in the SCS aerosol environment.

  18. Mount St. Helens related aerosol properties from solar extinction measurements

    SciTech Connect

    Michalsky, J.J.; Kleckner, E.W.; Stokes, G.M.

    1980-11-01

    The optical extinction due to the introduction of aerosols and aerosol-precursors into the troposphere and stratosphere during the major eruptive phase of Mount St. Helens, Washington, is quantified. The concentration is on the two-week period centered on the major eruption of 22 July 1980. (ACR)

  19. Aerosol Properties under Air Quality Control Measures of APEC 2014 in Beijing

    NASA Astrophysics Data System (ADS)

    Chen, X.; Xu, H.; Lv, Y.; Xie, Y.; Li, K.; Li, Z.; Li, D.; Ma, Y.; Mei, X.

    2015-12-01

    Because the economic and society were developing fast in the middle of last century, Los Angeles and London both were polluted by photochemical smog, which massacred thousands of people. Now, many regions are often covered by heavy haze in those large developing countries, especially in China and India. The Asia-Pacific Economic Cooperation (APEC) was held in Beijing during 5-11 November 2014. Beijing, Hebei, Tianjin, Shandong, Shanxi, Inner Mongolia reduced air pollution emissions for the APEC 2014 meeting held in Beijing. Only in Hebei province, there were 1028 factories stopped or restricted and 881 construction sites stopped. Half of the cars were prohibited driving even in the Zibo city which is 400 km far from Beijing. For scientific aims, these control measures were indeed a huge and uncommon atmospheric experiment led by the government. During the experiment, what did the "APEC Blue" mean? We analyzed aerosol properties with the data of an AERONET site in Beijing which is located 500m far from the main reception hall of APEC 2014. The Cimel solar photometers can give a series parameters of aerosol and water vapor. In this paper, we used CE318 solar photometer which is the main instrument of NASA AERONET. The CE318 of RADI belongs to the Chinese SONET (Sun-sky radiometer Observation NETwork) too. We analyzed the total, coarse and fine Aerosol Optical Depth (AOD), Fine-Mode Fraction (FMF) and Ångström exponent, Size Distribution and Real Refractive Index. In conclusion, the aerosol properties were analysed with the measurements of a sun photometer. During the APEC 2014, AOD decreased obviously with a 0.27 mean value compared with the annual mean 0.7. Around Beijing, the southern is polluted emission area including the cross part of Shandong, Shanxi, Hebei, Henan four provinces, and the northern is clean for less fine mode particles emission in the large Inner Mongolia province. In fact, during the APEC 2014, the weather condition was not good for the

  20. Design of a personal annular denuder sampler to measure atmospheric aerosols and gases

    NASA Astrophysics Data System (ADS)

    Koutrakis, P.; Fasano, A. M.; Slater, J. L.; Spengler, J. D.; McCarthy, J. F.; Leaderer, B. P.

    A personal sampling device has been designed to measure atmospheric gases and particles. This sampling system includes a glass impactor, an annular denuder and a filter pack. The glass impactor consists of an entrance section containing the inlet tube, the acceleration jet, and the impaction plate which is mounted at the entrance to the annular denuder. The impaction plate is a removable porous glass disk which can be impregnated with mineral oil to avoid bounce-off of the collected particles during sampling. The impactor has been designed to have a 50% aerodynamic particle cut-off point of 2.5μm, at flow rates of 4 and 2 ℓ min -1. For each flow, a different inlet has been designed with acceleration jet diameter of 0.250 and 0.190 mm, respectively. The annular denuder can be coated with citric acid to collect NH 3 and nicotine vapors. Also collection of SO 2, HNO 3 and HNO 2 is possible by coating the denuder with sodium carbonate. The last component of the designed personal sampler is a filter pack containing a 37-mm Teflon filter which is used to measure fine particle mass, aerosol strong acidity, sulfates and nitrates. The Teflon filter can be followed by a citric acid coated glass fiber filter used to collect nicotine which originates from the volatilization of the particle-phase nicotine collected on the Teflon filter. The ability of the personal sampler to collect fine particles was examined by conducting indoor aerosol sampling experiments. Also, ammonia collection efficiency tests were performed to characterize the personal denuder. The findings of these experiments showed that the designed personal sampler can be adequate for measuring human exposures to acid aerosols. In addition, the performance evaluation of the sampler to collect environmental tobacco smoke was investigated by conducting chamber tests.

  1. 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

  2. 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

  3. In situ measurements constraining the role of sulphate aerosols in mid-latitude ozone depletion

    NASA Technical Reports Server (NTRS)

    Fahey, D. W.; Kawa, S. R.; Woodbridge, E. L.; Tin, P.; Wilson, J. C.; Jonsson, H. H.; Dye, J. E.; Baumgardner, D.; Borrmann, S.; Toohey, D. W.

    1993-01-01

    In situ measurements of stratospheric sulphate aerosol, reactive nitrogen and chlorine concentrations at middle latitudes confirm the importance of aerosol surface reactions that convert active nitrogen to a less active, reservoir form. This makes mid-latitude stratospheric ozone less vulnerable to active nitrogen and more vulnerable to chlorine species. The effect of aerosol reactions on active nitrogen depends on gas phase reaction rates, so that increases in aerosol concentration following volcanic eruptions will have only a limited effect on ozone depletion at these latitudes.

  4. Chemical Characterization of Aerosols on the East Coast of the United States Using Aircraft and Ground-Based Stations during the CLAMS Experiment.

    NASA Astrophysics Data System (ADS)

    de Almeida Castanho, Andréa D.; Vanderlei Martins, J.; Hobbs, Peter V.; Artaxo, Paulo; Remer, Lorraine; Yamasoe, Marcia; Colarco, Peter R.

    2005-04-01

    The Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment was carried out off the central East Coast of the United States in July 2001. During CLAMS, aerosol particle mass was measured at two ground stations and on the University of Washington's Convair 580 research aircraft. Physical and chemical characteristics of the aerosols were identified and quantified. Three main aerosol regimes were identified in the region and are discussed in this work: local pollution/sea salt background, long-range transported dust, and long-range transported pollution. The major component measured in the fine mode of the aerosol on the ground at Wallops Island, Virginia, was sulfate, estimated as NH4HSO4, which accounted for 55% ± 9% on average of the fine particle mass (FPM) during the experiment period. Black carbon concentrations accounted for 3% ± 1% of FPM; soil dust was also present, representing on average 6% ± 8% of FPM. The difference between the sum of the masses of the measured compounds and the total fine particle mass was 36% ± 10% of FPM, which is attributed primarily to nitrates and organic carbon that were not measured. Aerosol chemical composition in the atmospheric column is also discussed and compared with ground-based measurements. Aerosol dust concentration reached 40% of FPM during an incursion of Saharan dust between 24 and 26 July. Sulfate aerosol reached 70% of FPM during the transport of regional pollution on 17 July. Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical thickness, coupled with air parcel back trajectories, supported the conclusion of episodes of long-range transport of dust from the Sahara Desert and pollutants from the continental United States.

  5. Quantifying Above-Cloud Aerosols through Integrating Multi-Sensor Measurements from A-Train Satellites

    NASA Technical Reports Server (NTRS)

    Zhang, Yan

    2012-01-01

    Quantifying above-cloud aerosols can help improve the assessment of aerosol intercontinental transport and climate impacts. Large-scale measurements of aerosol above low-level clouds had been generally unexplored until very recently when CALIPSO lidar started to acquire aerosol and cloud profiles in June 2006. Despite CALIPSO s unique capability of measuring above-cloud aerosol optical depth (AOD), such observations are substantially limited in spatial coverage because of the lidar s near-zero swath. We developed an approach that integrates measurements from A-Train satellite sensors (including CALIPSO lidar, OMI, and MODIS) to extend CALIPSO above-cloud AOD observations to substantially larger areas. We first examine relationships between collocated CALIPSO above-cloud AOD and OMI absorbing aerosol index (AI, a qualitative measure of AOD for elevated dust and smoke aerosol) as a function of MODIS cloud optical depth (COD) by using 8-month data in the Saharan dust outflow and southwest African smoke outflow regions. The analysis shows that for a given cloud albedo, above-cloud AOD correlates positively with AI in a linear manner. We then apply the derived relationships with MODIS COD and OMI AI measurements to derive above-cloud AOD over the whole outflow regions. In this talk, we will present spatial and day-to-day variations of the above-cloud AOD and the estimated direct radiative forcing by the above-cloud aerosols.

  6. Radiocarbon measurements of black carbon in aerosols and ocean sediments

    NASA Astrophysics Data System (ADS)

    Masiello, C. A.; Druffel, E. R. M.; Currie, L. A.

    2002-03-01

    Black carbon (BC) is the combustion-altered, solid residue remaining after biomass burning and fossil fuel combustion. Radiocarbon measurements of BC provide information on the residence time of BC in organic carbon pools like soils and sediments, and also provide information on the source of BC by distinguishing between fossil fuel and biomass combustion byproducts. We have optimized dichromate-sulfuric acid oxidation for the measurement of radiocarbon in BC. We also present comparisons of BC 14C measurements on NIST aerosol SRM 1649a with previously published bulk aromatic 14C measurements and individual polycyclic aromatic hydrocarbon (PAH) 14C measurements on the same NIST standard. Dichromate-sulfuric acid oxidation belongs to the chemical class of BC measurement methods, which rely on the resistance of some forms of BC to strong chemical oxidants. Dilute solutions of dichromate-sulfuric acid degrade BC and marine-derived carbon at characteristic rates from which a simple kinetic formula can be used to calculate concentrations of individual components (Wolbach and Anders, 1989). We show that: (1) dichromate-sulfuric acid oxidation allows precise, reproducible 14C BC measurements; (2) kinetics calculations give more precise BC yield information when performed on a % OC basis (vs. a % mass basis); (3) kinetically calculated BC concentrations are similar regardless of whether the oxidation is performed at 23°C or 50°C; and (4) this method yields 14C BC results consistent with previously published aromatic 14C data for an NIST standard. For the purposes of intercomparison, we report % mass and carbon results for two commercially available BC standards. We also report comparative data from a new thermal method applied to SRM 1649a, showing that thermal oxidation of this material also follows the simple kinetic sum of exponentials model, although with different time constants.

  7. New capabilities for space-based cloud and aerosols measurements: The Cloud-Aerosol Transport System (CATS)

    NASA Astrophysics Data System (ADS)

    Yorks, J. E.; McGill, M. J.; Hlavka, D. L.; Palm, S. P.; Hart, W. D.; Nowottnick, E. P.; Vaughan, M.; Rodier, S. D.; Colarco, P. R.; da Silva, A.; Buchard-Marchant, V.

    2013-12-01

    Current uncertainties in cloud and aerosol properties limit our ability to accurately model the Earth's climate system and predict climate change. These limitations are due primarily to difficulties in adequately measuring aerosols and clouds on a global scale. NASA's A-Train satellites provide an unprecedented opportunity to address these uncertainties. In particular, the Cloud-Aerosol Lidar Infrared Pathfinder Spaceborne Observations (CALIPSO) satellite provides vertical profiles of cloud and aerosol properties. The CALIOP lidar onboard CALIPSO has reached its seventh year of operation, well past its expected lifetime. The ATLID lidar on EarthCARE is not expected to launch until 2016 or later. If the CALIOP lidar fails before a new mission is operational, there will be a gap in global lidar measurements. The Cloud-Aerosol Transport System (CATS), built at NASA Goddard Space Flight Center as a payload for the International Space Station (ISS), is set to launch in the summer of 2014. CATS is an elastic backscatter lidar with three wavelengths (1064, 532, 355 nm) and HSRL capability at 532 nm. Depolarization measurements will be made at all three wavelengths. The ISS orbit is a 51 degree inclination orbit at an altitude of about 405 km. This orbit provides more comprehensive coverage of the tropics and mid-latitudes than sun-synchronous orbiting sensors, with nearly a three day repeat cycle. Thus, science applications of CATS include cloud and aerosol climate studies, air quality monitoring, and smoke/volcanic plume tracking. The primary science objectives of CATS include: continuing the CALIPSO aerosol and cloud vertical profile data record, providing near real time data to support operational applications such as air quality modeling, and advancing technology in support of future mission development using the HSRL channel. Furthermore, the vertical profiles of cloud and aerosol properties provided by CATS will complement current and future passive satellite

  8. Chemically-resolved aerosol eddy covariance flux measurements in urban Mexico City during MILAGRO 2006

    NASA Astrophysics Data System (ADS)

    Zalakeviciute, R.; Alexander, M. L.; Allwine, E.; Jimenez, J. L.; Jobson, B. T.; Molina, L. T.; Nemitz, E.; Pressley, S. N.; VanReken, T. M.; Ulbrich, I. M.; Velasco, E.; Lamb, B. K.

    2012-08-01

    As part of the MILAGRO 2006 field campaign, the exchange of atmospheric aerosols with the urban landscape was measured from a tall tower erected in a heavily populated neighborhood of Mexico City. Urban submicron aerosol fluxes were measured using an eddy covariance method with a quadrupole aerosol mass spectrometer during a two week period in March, 2006. Nitrate and ammonium aerosol concentrations were elevated at this location near the city center compared to measurements at other urban sites. Significant downward fluxes of nitrate aerosol, averaging -0.2 μg m-2 s-1, were measured during daytime. The urban surface was not a significant source of sulfate aerosols. The measurements also showed that primary organic aerosol fluxes, approximated by hydrocarbon-like organic aerosols (HOA), displayed diurnal patterns similar to CO2 fluxes and anthropogenic urban activities. Overall, 47% of submicron organic aerosol emissions were HOA, 35% were oxygenated (OOA) and 18% were associated with biomass burning (BBOA). Organic aerosol fluxes were bi-directional, but on average HOA fluxes were 0.1 μg m-2 s-1, OOA fluxes were -0.03 μg m-2 s-1, and BBOA fluxes were -0.03 μg m-2 s-1. After accounting for size differences (PM1 vs PM2.5) and using an estimate of the black carbon component, comparison of the flux measurements with the 2006 gridded emissions inventory of Mexico City, showed that the daily-averaged total PM emission rates were essentially identical for the emission inventory and the flux measurements. However, the emission inventory included dust and metal particulate contributions, which were not included in the flux measurements. As a result, it appears that the inventory underestimates overall PM emissions for this location.

  9. Improved and new balloon-borne instruments for the measurements of stratospheric aerosols