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Sample records for aerosol transport events

  1. Temporal consistency of lidar observations during aerosol transport events in the framework of the ChArMEx/ADRIMED campaign at Minorca in June 2013

    NASA Astrophysics Data System (ADS)

    Chazette, Patrick; Totems, Julien; Ancellet, Gérard; Pelon, Jacques; Sicard, Michaël

    2016-03-01

    We performed synergetic daytime and nighttime active and passive remote-sensing observations at Minorca (Balearic Islands, Spain), over more than 3 weeks during the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Effect in the Mediterranean (ChArMEx/ADRIMED) special observation period (SOP 1a, June-July 2013). We characterized the aerosol optical properties and type in the low and middle troposphere using an automated procedure combining Rayleigh-Mie-Raman lidar (355, 387 and 407 nm) with depolarization (355 nm) and AERONET Cimel® sun-photometer data. Results show a high variability due to varying dynamical forcing. The mean column-averaged lidar backscatter-to-extinction ratio (BER) was close to 0.024 sr-1 (lidar ratio of ˜ 41.7 sr), with a large dispersion of ±33 % over the whole observation period due to changing atmospheric transport regimes and aerosol sources. The ground-based remote-sensing measurements, coupled with satellite observations, allowed the documentation of (i) dust particles up to 5 km (above sea level) in altitude originating from Morocco and Algeria from 15 to 18 June with a peak in aerosol optical thickness (AOT) of 0.25 ± 0.05 at 355 nm, (ii) a long-range transport of biomass burning aerosol (AOT = 0.18 ± 0.16) related to North American forest fires detected from 26 to 28 June 2013 by the lidar between 2 and 7 km and (iii) mixture of local sources including marine aerosol particles and pollution from Spain. During the biomass burning event, the high value of the particle depolarization ratio (8-14 %) may imply the presence of dust-like particles mixed with the biomass burning aerosols in the mid-troposphere. For the field campaign period, we also show linearity with SEVIRI retrievals of the aerosol optical thickness despite 35 % relative bias, which is discussed as a function of aerosol type.

  2. Temporal consistency of lidar observables during aerosol transport events in the framework of the ChArMEx/ADRIMED campaign at Menorca Island in June 2013

    NASA Astrophysics Data System (ADS)

    Chazette, P.; Totems, J.; Ancellet, G.; Pelon, J.; Sicard, M.

    2015-11-01

    We performed synergetic daytime and night-time active and passive remote sensing observations at Menorca (Balearic Island, Spain), over more than 3 weeks during the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Effect in the Mediterranean (ChArMEx/ADRIMED) special observation period (SOP 1a, June-July 2013). We characterized the aerosol optical properties and type in the low and middle troposphere using an automated procedure combining Rayleigh-Mie-Raman lidar (355, 387 and 407 nm) with depolarization (355 nm) and AERONET Cimel® sun-photometer data. Results show a high variability due to varying dynamical forcing. The mean column-averaged lidar backscatter-to-extinction ratio (BER) was close to 0.024 sr-1 (lidar ratio of ∼ 41.7 sr), with a large dispersion of ±33 % over the whole observation period due to changing atmospheric transport regimes and aerosol sources. The ground-based remote sensing measurements, coupled with satellite observations, allowed to document (i) dust particles up to 5 km a.s.l. in altitude originating from Morocco and Algeria from 15 to 18 June with a peak in aerosol optical thickness (AOT) of 0.25 ± 0.05 at 355 nm, (ii) a long-range transport of biomass burning aerosol (AOT = 0.18 ± 0.16) related to North American forest fires detected from 26 to 28 June 2013 by the lidar between 2 and 7 km and (iii) mixture of local sources including marine aerosol particles and pollution from Spain. During the biomass burning event, the high value of the particle depolarization ratio (8-14 %) may imply the presence of dust-like particles mixed with the biomass burning aerosols in the mid troposphere. We show also linearity with SEVIRI retrievals of the aerosol optical thickness within 35 % relative bias, which is discussed as a function of aerosol type.

  3. Aerosol Transport Over Equatorial Africa

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  4. Lidar data assimilation for improved analyses of volcanic aerosol events

    NASA Astrophysics Data System (ADS)

    Lange, Anne Caroline; Elbern, Hendrik

    2014-05-01

    Observations of hazardous events with release of aerosols are hardly analyzable by today's data assimilation algorithms, without producing an attenuating bias. Skillful forecasts of unexpected aerosol events are essential for human health and to prevent an exposure of infirm persons and aircraft with possibly catastrophic outcome. Typical cases include mineral dust outbreaks, mostly from large desert regions, wild fires, and sea salt uplifts, while the focus aims for volcanic eruptions. In general, numerical chemistry and aerosol transport models cannot simulate such events without manual adjustments. The concept of data assimilation is able to correct the analysis, as long it is operationally implemented in the model system. Though, the tangent-linear approximation, which describes a substantial precondition for today's cutting edge data assimilation algorithms, is not valid during unexpected aerosol events. As part of the European COPERNICUS (earth observation) project MACC II and the national ESKP (Earth System Knowledge Platform) initiative, we developed a module that enables the assimilation of aerosol lidar observations, even during unforeseeable incidences of extreme emissions of particulate matter. Thereby, the influence of the background information has to be reduced adequately. Advanced lidar instruments comprise on the one hand the aspect of radiative transfer within the atmosphere and on the other hand they can deliver a detailed quantification of the detected aerosols. For the assimilation of maximal exploited lidar data, an appropriate lidar observation operator is constructed, compatible with the EURAD-IM (European Air Pollution and Dispersion - Inverse Model) system. The observation operator is able to map the modeled chemical and physical state on lidar attenuated backscatter, transmission, aerosol optical depth, as well as on the extinction and backscatter coefficients. Further, it has the ability to process the observed discrepancies with lidar

  5. In-situ, sunphotometer and Raman lidar observations of aerosol transport events in the western Mediterranean during the June 2013 ChArMEx campaign

    NASA Astrophysics Data System (ADS)

    Totems, Julien; Sicard, Michael; Bertolin, Santi; Boytard, Mai-Lan; Chazette, Patrick; Comeron, Adolfo; Dulac, Francois; Hassanzadeh, Sahar; Lange, Diego; Marnas, Fabien; Munoz, Constantino; Shang, Xiaoxia

    2014-05-01

    We present a preliminary analysis of aerosol observations performed in June 2013 in the western Mediterranean at two stations set up in Barcelona and Menorca (Spain) in the framework of the ChArMEx (Chemistry Aerosol Mediterranean Experiment) project. The Barcelona station was equipped with the following fixed instruments belonging to the Universitat Politècnica de Catalunya (UPC): an AERONET (Aerosol Robotic Network) sun-photometer, an MPL (Micro Pulse Lidar) lidar and the UPC multi-wavelength lidar. The MPL lidar works at 532 nm and has a depolarization channel, while the UPC lidar works at 355, 532 and 1064 nm, and also includes two N2- (at 387 and 607 nm) and one H2O-Raman (at 407 nm) channels. The MPL system works continuously 24 hour/day. The UPC system was operated on alert in coordination with the research aircrafts plans involved in the campaign. In Cap d'en Font, Menorca, the mobile laboratory of the Laboratoire des Sciences du Climat et de l'Environnement hosted an automated (AERONET) and a manual (Microtops) 5-lambda sunphotometer, a 3-lambda nephelometer, a 7-lambda aethalometer, as well as the LSCE Water vapor Aerosol LIdar (WALI). This mini Raman lidar, first developed and validated for the HyMEX (Hydrological cycle in the Mediterranean eXperiment) campaign in 2012, works at 355 nm for eye safety and is designed with a short overlap distance (<300m) to probe the lower troposphere. It includes depolarization, N2- and H2O-Raman channels. H2O observations have been calibrated on-site by different methods and show good agreement with balloon measurements. Observations at Cap d'en Font were quasi-continuous from June 10th to July 3rd, 2013. The lidar data at both stations helped direct the research aircrafts and balloon launches to interesting plumes of particles in real time for in-situ measurements. Among some light pollution background from the European continent, a typical Saharan dust event and an unusual American dust/biomass burning event are

  6. Observation of the simultaneous transport of Asian mineral dust aerosols with anthropogenic pollutants using a POPC during a long-lasting dust event in late spring 2014

    NASA Astrophysics Data System (ADS)

    Pan, Xiaole; Uno, Itsushi; Hara, Yukari; Kuribayashi, Masatoshi; Kobayashi, Hiroshi; Sugimoto, Nobuo; Yamamoto, Shigekazu; Shimohara, Takaaki; Wang, Zifa

    2015-03-01

    We observed a long-lasting dust event from 25 May to 2 June 2014, using a polarization optical particle counter (POPC). The transport of dust plumes over East Asia was verified on the basis of observations of Moderate Resolution Imaging Spectroradiometer, a lidar network, and surface synoptic observation stations. Mixing of dust and anthropogenic pollutants was investigated according to the variation in the depolarization ratio as a function of particle size. The nonsphericity of dust particles varied due to the impact of anthropogenic pollutants on their pathway. In the coarse mode, dust particles always had a clear nonspherical configuration, although large amounts of nitrate were also present. Supermicron particles are occasionally present in a spherical configuration, possibly due to the complex mixing of natural dust and anthropogenic particles. Statistically, ~64% of the total nitrate mass was deemed to be transported from outside of Japan due to a trapping effect in the dust plume.

  7. Aerosol and CCN properties at Princess Elisabeth station, East Antarctica: seasonality, new particle formation events and properties around precipitation events

    NASA Astrophysics Data System (ADS)

    Mangold, Alexander; Laffineur, Quentin; De Backer, Hugo; Herenz, Paul; Wex, Heike; Gossart, Alexandra; Souverijns, Niels; Gorodetskaya, Irina; Van Lipzig, Nicole

    2016-04-01

    Since 2010, several complementary ground-based instruments for measuring the aerosol composition of the Antarctic atmosphere have been operated at the Belgian Antarctic research station Princess Elisabeth, in Dronning Maud Land, East Antarctica (71.95° S, 23.35° E, 1390 m asl.). In addition, three ground-based remote sensing instruments for cloud and precipitation observations have been installed for continuous operation, including a ceilometer (cloud base height, type, vertical extent), a 24 Ghz micro-rain radar (vertical profiles of radar effective reflectivity and Doppler velocity), and a pyrometer (cloud base temperature). The station is inhabited from November to end of February and operates under remote control during the other months. In this contribution, the general aerosol and cloud condensation nuclei (CCN) properties will be described with a special focus on new particle formation events and around precipitation events. New particle formation events are important for the atmospheric aerosol budget and they also show that aerosols are not only transported to Antarctica but are also produced there, also inland. Aerosols are essential for cloud formation and therefore also for precipitation, which is the only source for mass gain of the Antarctic ice sheet. Measured aerosol properties comprise size distribution, total number, total mass concentration, mass concentration of light-absorbing aerosol and absorption coefficient and total scattering coefficient. In addition, a CCN counter has been operated during austral summers 2013/14, 2014/15 and 2015/16. The baseline total number concentration N-total was around some hundreds of particles/cm3. During new particle formation events N-total increased to some thousands of particles/cm3. Simultaneous measurements of N-total, size distribution and CCN number revealed that mostly the number of particles smaller than 100 nm increased and that the concentration of cloud condensation nuclei increased only very

  8. Sources, Transport, and Climate Impacts of Biomass Burning Aerosols

    NASA Technical Reports Server (NTRS)

    Chin, Mian

    2010-01-01

    In this presentation, I will first talk about fundamentals of modeling of biomass burning emissions of aerosols, then show the results of GOCART model simulated biomass burning aerosols. I will compare the model results with observations of satellite and ground-based network in terms of total aerosol optical depth, aerosol absorption optical depth, and vertical distributions. Finally the long-range transport of biomass burning aerosols and the climate effects will be addressed. I will also discuss the uncertainties associated with modeling and observations of biomass burning aerosols

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  10. Street canyon aerosol pollutant transport measurements.

    PubMed

    Longley, I D; Gallagher, M W; Dorsey, J R; Flynn, M; Bower, K N; Allan, J D

    2004-12-01

    Current understanding of dispersion in street canyons is largely derived from relatively simple dispersion models. Such models are increasingly used in planning and regulation capacities but are based upon a limited understanding of the transport of substances within a real canyon. In recent years, some efforts have been made to numerically model localised flow in idealised canyons (e.g., J. Appl. Meteorol. 38 (1999) 1576-89) and stepped canyons (Assimakopoulos V. Numerical modelling of dispersion of atmospheric pollution in and above urban canopies. PhD thesis, Imperial College, London, 2001) but field studies in real canyons are rare. To further such an understanding, a measurement campaign has been conducted in an asymmetric street canyon with busy one-way traffic in central Manchester in northern England. The eddy correlation method was used to determine fluxes of size-segregated accumulation mode aerosol. Measurements of aerosol at a static location were made concurrently with measurements on a platform lift giving vertical profiles. Size-segregated measurements of ultrafine and coarse particle concentrations were also made simultaneously at various heights. In addition, a small mobile system was used to make measurements of turbulence at various pavement locations within the canyon. From this data, various features of turbulent transport and dispersion in the canyon will be presented. The concentration and the ventilation fluxes of vehicle-related aerosol pollutants from the canyon will be related to controlling factors. The results will also be compared with citywide ventilation data from a separate measurement campaign conducted above the urban canopy.

  11. Computational modeling and experimental characterization of indoor aerosol transport

    SciTech Connect

    Konecni, S.; Whicker, J. J.; Martin, R. A.

    2002-01-01

    When a hazardous aerosol or gas is inadvertently or deliberately released in an occupied facility, the airborne material presents a hazard to people. Inadvertent accidents and exposures continue to occur in Los Alamos and other nuclear facilities despite state-of-art engineering and administrative controls, and heightened diligence. Despite the obvious need in occupational settings and for homeland defense, the body of research in hazardous aerosol dispersion and control in large, complex, ventilated enclosures is extremely limited. The science governing generation, transport, inhalation, and detection of airborne hazards is lacking and must be developed to where it can be used by engineers or safety professionals in the prediction of worker exposure, in the prevention of accidents, or in the mitigation of terrorist actions. In this study, a commercial computational fluid dynamics (CFD) code, CFX5.4, and experiments were used to assess flow field characteristics, and to investigate aerosol release and transport in a large, ventilated workroom in a facility at Savannah River Site. Steady state CFD results illustrating a complex, ventilation-induced, flow field with vortices, velocity gradients, and quiet zones are presented, as are time-dependent CFD and experimental aerosol dispersion results. The comparison of response times between CFD and experimental results was favorable. It is believed that future applications of CFD and experiments can have a favorable impact on the design of ventilation (HVAC) systems and worker safety with consideration to facility costs. Ultimately, statistical methods will be used in conjunction with CFD calculations to determine the optimal number and location of detectors, as well as optimal egress routes in event of a release.

  12. Aerosol-cloud associations over Gangetic Basin during a typical monsoon depression event using WRF-Chem simulation

    NASA Astrophysics Data System (ADS)

    Sarangi, Chandan; Tripathi, S. N.; Tripathi, Shivam; Barth, Mary C.

    2015-10-01

    To study aerosol-cloud interactions over the Gangetic Basin of India, the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) has been applied to a typical monsoon depression event prevalent between the 23 and 29 August 2009. This event was sampled during the Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) aircraft campaign, providing measurements of aerosol and cloud microphysical properties from two sorties. Comparison of the simulated meteorological, thermodynamical, and aerosol fields against satellite and in situ aircraft measurements illustrated that the westward propagation of the monsoon depression and the cloud, aerosol, and rainfall spatial distribution was simulated reasonably well using anthropogenic emission rates from Monitoring Atmospheric Composition and Climate project along with cityZEN projects (MACCity)+Intercontinental Chemical Transport Experiment Phase B anthropogenic emission rates. However,the magnitude of aerosol optical depth was underestimated by up to 50%. A simulation with aerosol emissions increased by a factor of 6 over the CAIPEEX campaign domain increased the simulated aerosol concentrations to values close to the observations, mainly within boundary layer. Comparison of the low-aerosol simulation and high-aerosol simulation for the two sorties illustrated that more anthropogenic aerosols increased the cloud condensing nuclei (CCN) and cloud droplet mass concentrations. The number of simulated cloud droplets increased while the cloud droplet effective radii decreased, highlighting the importance of CCN-cloud feedbacks over this region. The increase in simulated anthropogenic aerosols (including absorbing aerosols) also increased the temperature of air parcels below clouds and thus the convective available potential energy (CAPE). The increase in CAPE intensified the updraft and invigorated the cloud, inducing formation of deeper clouds with more ice-phase hydrometeors for both cases

  13. Smoke aerosol transport patterns over the Maritime Continent

    NASA Astrophysics Data System (ADS)

    Xian, Peng; Reid, Jeffrey S.; Atwood, Samuel A.; Johnson, Randall S.; Hyer, Edward J.; Westphal, Douglas L.; Sessions, Walter

    2013-03-01

    Smoke transport patterns over the Maritime Continent (MC) are studied through a combination of approaches, including a) analyzing AODs obtained from satellite products; b) aerosol transport modeling with AOD assimilation along with the atmospheric flow patterns; c) analyzing smoke wet deposition distributions; and d) examining forward trajectories for smoke events defined in this study. It is shown that smoke transport pathways are closely related to the low-level atmospheric flow, i.e., during June-Sept, smoke originating from the MC islands with a dominant source over central and southern Sumatra, and southern and western Borneo, is generally transported northwestward south of the equator and northeastward north of the equator with the cross-equatorial flow, to the South China Sea (SCS), the Philippines and even further to the western Pacific. During the October-November transitional period, smoke transport paths are more zonally oriented compared to June-September. Smoke originating from Java, Bali, Timor etc, and southern New Guinea, which are in the domain of easterlies and southeasterlies during the boreal summer (June-November), is generally transported westward. It is also found that smoke transport over the MC exhibits multi-scale variability. Smoke typically lives longer and can be transported farther in El Niño years and later MJO phases compared with non El Niño years and earlier MJO phases. During El Niño periods there is much stronger westward transport to the east tropical Indian Ocean. Finally, orographic effect on smoke transport over the MC is also clearly discernable.

  14. MELCOR aerosol transport module modification for NSSR-1

    SciTech Connect

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

    1996-03-01

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

  15. Aplication of LIRIC algorithm to study aerosol transport over Belsk, Poland

    NASA Astrophysics Data System (ADS)

    Pietruczuk, Aleksander; Posyniak, Michał

    2015-04-01

    In this work synergy of measurements done by of a LIDAR and a sun-sky scanning photometer is presented. The LIdar-Radiometer Inversion Code (LIRIC) was applied to study periodic events of increased values of the aerosol optical depth (AOD) observed at Belsk (Poland). Belsk is a background site located in a rural area around 50 km south from Warsaw. Events of increased AOD occur mainly during spring and they coincide with events of elevated concentrations of particulate matter (PM10). This phenomenon is observed in all eastern Europe, e.g. in Minsk, and is caused by long range aerosol transport. Our previous work showed aerosol transport from the border between Belarus, Ukraine and Russia in the planetary boundary layer (PBL), and from north Africa in the free troposphere. The LIRIC algorithm, which uses optical and microphysical properties of the aerosol derived from photometric measurements and LIDAR profiles, was applied to study vertical distribution of fine and coarse modes of aerosol. The analysis of the airmass backward trajectories and models results (DREAM and NAAPS)was also used to determine a possible aerosol type and its source region. This study proved our previous findings. Most of events with increased AODs are observed during spring. In this season the fine mode aerosol is mainly present in the PBL. On the basis of the trajectory analysis and the NAAPS results we presume that it is the absorbing aerosol originating from the regions of seasonal biomass burning in eastern Europe, i.e. the area mentioned above. The events with increased AODs were also found during summer. In this case the fine mode aerosol is transported in the PBL a like to spring season. However, our analysis of trajectories and model results indicated western Europe as a source region. It is probably urban/industrial aerosol. The coarse mode aerosol is transported mainly in the free troposphere as separate layers. The analysis of backward trajectories indicates northern Africa as a

  16. Evaluation of regional air quality models in the presence of moderate to strong aerosol events

    NASA Astrophysics Data System (ADS)

    O'Neill, N. T.; Thulasiraman, S.; Pancrati, O.; Aube, M.; Lupu, A.; Neary, L.; Strawbridge, K.; Freemantle, J.; Kaminski, J.; McConnell, J.

    2006-12-01

    During the 2004 to 2006 period a program of synchronized sunphotometry and lidar backscatter measurements were carried out at Egbert, Ontario (70 km north of Toronto). A variety of events, ranging from moderate to strong pollution events, long and short distance smoke transport, long distance dust transport and the presence of thin homogeneous clouds were registered and optically analyzed. These data were employed to help evaluate the performance of the Canadian GEM-AQ air quality model as well an aerosol optical assimilation model (NOMAD). The evaluations were based on optical indicators of integrated aerosol content (aerosol optical depth), particle size indicators such as Angstrom exponent, and vertical profiles of the aerosol backscatter ratio. Some preliminary analyses will be presented; the focus will be on the problems associated with emissions modelling, the influence of cloud screening algorithms in the data and in the model, the robustness of particle size information in the passive optical data and the ability of the models to capture subtle variations, and the vertical performance of the models relative to the lidar backscatter data.

  17. Near Real Time Vertical Profiles of Clouds and Aerosols from the Cloud-Aerosol Transport System (CATS) on the International Space Station

    NASA Astrophysics Data System (ADS)

    Yorks, J. E.; McGill, M. J.; Nowottnick, E. P.

    2015-12-01

    Plumes from hazardous events, such as ash from volcanic eruptions and smoke from wildfires, can have a profound impact on the climate system, human health and the economy. Global aerosol transport models are very useful for tracking hazardous plumes and predicting the transport of these plumes. However aerosol vertical distributions and optical properties are a major weakness of global aerosol transport models, yet a key component of tracking and forecasting smoke and ash. The Cloud-Aerosol Transport System (CATS) is an elastic backscatter lidar designed to provide vertical profiles of clouds and aerosols while also demonstrating new in-space technologies for future Earth Science missions. CATS has been operating on the Japanese Experiment Module - Exposed Facility (JEM-EF) of the International Space Station (ISS) since early February 2015. The ISS orbit provides more comprehensive coverage of the tropics and mid-latitudes than sun-synchronous orbiting sensors, with nearly a three-day repeat cycle. The ISS orbit also provides CATS with excellent coverage over the primary aerosol transport tracks, mid-latitude storm tracks, and tropical convection. Data from CATS is used to derive properties of clouds and aerosols including: layer height, layer thickness, backscatter, optical depth, extinction, and depolarization-based discrimination of particle type. The measurements of atmospheric clouds and aerosols provided by the CATS payload have demonstrated several science benefits. CATS provides near-real-time observations of cloud and aerosol vertical distributions that can be used as inputs to global models. The infrastructure of the ISS allows CATS data to be captured, transmitted, and received at the CATS ground station within several minutes of data collection. The CATS backscatter and vertical feature mask are part of a customized near real time (NRT) product that the CATS processing team produces within 6 hours of collection. The continuous near real time CATS data

  18. Evaluation of liquid aerosol transport through porous media.

    PubMed

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

    2016-07-01

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

  19. Evaluation of liquid aerosol transport through porous media

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  20. Improving Aerosol Transport to the Arctic in CAM5

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  1. Aerosol vertical distribution, optical properties and transport over Corsica (western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Léon, J.-F.; Augustin, P.; Mallet, M.; Bourrianne, T.; Pont, V.; Dulac, F.; Fourmentin, M.; Lambert, D.; Sauvage, B.

    2015-03-01

    This paper presents the aerosol vertical distribution observed in the western Mediterranean between February and April 2011 and between February 2012 and August 2013. An elastic backscattering lidar was continuously operated at a coastal site in the northern part of Corsica Island (Cap Corse) for a total of more than 14 000 h of observations. The aerosol extinction coefficient retrieved from cloud-free lidar profiles are analyzed along with the SEVIRI satellite aerosol optical depth (AOD). The SEVIRI AOD was used to constrain the retrieval of the aerosol extinction profiles from the lidar range-corrected signal and to detect the presence of dust or pollution aerosols. The daily average AOD at 550 nm is 0.16 (±0.09) and ranges between 0.05 and 0.80. A seasonal cycle is observed with minima in winter and maxima in spring-summer. High AOD days (above 0.3 at 550 nm) represent less than 10% of the totality of daily observations and correspond to the large scale advection of desert dust from Northern Africa or pollution aerosols from Europe. The respective origin of the air masses is confirmed using FLEXPART simulations in the backward mode. Dust events are characterized by a large turbid layer between 2 and 5 km height while pollution events show a lower vertical development with a thick layer below 3 km in altitude. However low level dust transport is also reported during spring while aerosol pollution layer between 2 and 4 km height has been also observed. We report an effective lidar ratio at 355 nm for pollution aerosols 68 (±13) Sr while it is 63 (±18) Sr for dust. The daily mean AOD at 355 nm for dust events is 0.61 (±0.14) and 0.71 (±0.16) for pollution aerosols events.

  2. Parameterization of Aerosol Sinks in Chemical Transport Models

    NASA Technical Reports Server (NTRS)

    Colarco, Peter

    2012-01-01

    The modelers point of view is that the aerosol problem is one of sources, evolution, and sinks. Relative to evolution and sink processes, enormous attention is given to the problem of aerosols sources, whether inventory based (e.g., fossil fuel emissions) or dynamic (e.g., dust, sea salt, biomass burning). On the other hand, aerosol losses in models are a major factor in controlling the aerosol distribution and lifetime. Here we shine some light on how aerosol sinks are treated in modern chemical transport models. We discuss the mechanisms of dry and wet loss processes and the parameterizations for those processes in a single model (GEOS-5). We survey the literature of other modeling studies. We additionally compare the budgets of aerosol losses in several of the ICAP models.

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

    SciTech Connect

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

    1984-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  5. Application of Aerosol Assimilation System of MODIS Radiances to Regional Chemical Transport Model

    NASA Astrophysics Data System (ADS)

    D'Allura, A.; Charmichael, G. R.; Tang, Y.; Chai, T.; Chung, C. E.; Anderson, T. L.

    2006-12-01

    We present results from an assimilation system of radiances from the MODIS channels that sense atmospheric aerosols over land and ocean on the chemical transport model STEM. A test case is designed to simulate transport of aerosols tracers over the area of interest which includes India, east and south Asia at 50km horizontal resolution. A detailed treatment of the source, transport and deposition of the aerosol species are included. The model simulates five aerosol components: sulfate, organic carbon, black carbon, dust and sea salt. Total AODs at 550nm wavelength over land and ocean and fine mode AODs at 550nm wavelength over ocean are the level 2 aerosol products from Terra MODIS channel four used in this application. The intent of the study is to verify the improvement in the model performances while the initial conditions are corrected using an Optimum Interpolation technique to assimilate the MODIS data. The model results are compared with ground-based measurements of aerosol optical depth (AOD) from the AERONET network. Sensitivity analyses are provided in order to describe the effect of changing in assimilation technique's free parameters. The method is designed to optimize the use of the information provided by fine mode AODs, which are available over ocean, coupled with the total AODs available also over land. Improvements on the model results using this approach are highlighted during specific event where the model has experienced low agreement with observed data. Results are also compared to other assimilations methods.

  6. Observations of the Interaction and/or Transport of Aerosols with Cloud or Fog during DRAGON Campaigns from AERONET Ground-Based Remote Sensing

    NASA Astrophysics Data System (ADS)

    Eck, Thomas; Holben, Brent; Schafer, Joel; Giles, David; Kim, Jhoon; Kim, Young; Sano, Itaru; Reid, Jeffrey; Pickering, Kenneth; Crawford, James; Sinyuk, Alexander; Trevino, Nathan

    2014-05-01

    Ground-based remote sensing observations from Aerosol Robotic Network (AERONET) sun-sky radiometers have recently shown several instances where cloud-aerosol interaction had resulted in modification of aerosol properties and/or in difficulty identifying some major pollution transport events due to aerosols being imbedded in cloud systems. AERONET has established Distributed Regional Aerosol Gridded Observation Networks (DRAGON) during field campaigns that are short-term (~2-3 months) relatively dense spatial networks of ~15 to 45 sun and sky scanning photometers. Recent major DRAGON field campaigns in Japan and South Korea (Spring 2012) and California (Winter 2013) have yielded observations of aerosol transport associated with clouds and/or aerosol properties modification as a result of fog interaction. Analysis of data from the Korean and Japan DRAGON campaigns shows that major fine-mode aerosol transport events are sometimes associated with extensive cloud cover and that cloud-screening of observations often filter out significant pollution aerosol transport events. The Spectral De-convolution Algorithm (SDA) algorithm was utilized to isolate and analyze the fine-mode aerosol optical depth signal for these cases of persistent and extensive cloud cover. Additionally, extensive fog that was coincident with aerosol layer height on some days in both Korea and California resulted in large increases in fine mode aerosol radius, with a mode of cloud-processed or residual aerosol of radius ~0.4-0.5 micron sometimes observed. Cloud processed aerosol may occur much more frequently than AERONET data suggest due to inherent difficulty in observing aerosol properties near clouds from remote sensing observations. These biases of aerosols associated with clouds would likely be even greater for satellite remote sensing retrievals of aerosol properties near clouds due to 3-D effects and sub-pixel cloud contamination issues.

  7. Analysis of the Interaction and Transport of Aerosols with Cloud or Fog in East Asia from AERONET and Satellite Remote Sensing: 2012 DRAGON Campaigns and Climatological Data

    NASA Astrophysics Data System (ADS)

    Eck, T. F.; Holben, B. N.; Reid, J. S.; Lynch, P.; Schafer, J.; Giles, D. M.; Kim, J.; Kim, Y. J.; Sano, I.; Arola, A. T.; Munchak, L. A.; O'Neill, N. T.; Lyapustin, A.; Sayer, A. M.; Hsu, N. Y. C.; Randles, C. A.; da Silva, A. M., Jr.; Govindaraju, R.; Hyer, E. J.; Pickering, K. E.; Crawford, J. H.; Sinyuk, A.; Smirnov, A.

    2015-12-01

    Ground-based remote sensing observations from Aerosol Robotic Network (AERONET) sun-sky radiometers have recently shown several instances where cloud-aerosol interaction had resulted in modification of aerosol properties and/or in difficulty identifying some major pollution transport events due to aerosols being imbedded in cloud systems. Major Distributed Regional Aerosol Gridded Observation Networks (DRAGON) field campaigns involving multiple AERONET sites in Japan and South Korea during Spring of 2012 have yielded observations of aerosol transport associated with clouds and/or aerosol properties modification as a result of fog interaction. Analysis of data from the Korean and Japan DRAGON campaigns shows that major fine-mode aerosol transport events are sometimes associated with extensive cloud cover and that cloud-screening of observations often filter out significant pollution aerosol transport events. The Spectral De-convolution Algorithm (SDA) algorithm was utilized to isolate and analyze the fine-mode aerosol optical depth (AODf) signal from AERONET data for these cases of persistent and extensive cloud cover. Satellite retrievals of AOD from MODIS sensors (from Dark Target, Deep Blue and MAIAC algorithms) were also investigated to assess the issue of detectability of high AOD events associated with high cloud fraction. Underestimation of fine mode AOD by the Navy Aerosol Analysis and Prediction System (NAAPS) and by the NASA Modern-Era Retrospective Analysis For Research And Applications Aerosol Re-analysis (MERRAaero) models at very high AOD at sites in China and Korea was observed, especially for observations that are cloud screened by AERONET (Level 2 data). Additionally, multi-year monitoring at several AERONET sites are examined for climatological statistics of cloud screening of fine mode aerosol events. Aerosol that has been affected by clouds or the near-cloud environment may be more prevalent than AERONET data suggest due to inherent difficulty in

  8. Measurements of aerosol chemistry during new particle formation events at a remote rural mountain site.

    PubMed

    Creamean, Jessie M; Ault, Andrew P; Ten Hoeve, John E; Jacobson, Mark Z; Roberts, Gregory C; Prather, Kimberly A

    2011-10-01

    Determining the major sources of particles that act as cloud condensation nuclei (CCN) represents a critical step in the development of a more fundamental understanding of aerosol impacts on cloud formation and climate. Reported herein are direct measurements of the CCN activity of newly formed ambient particles, measured at a remote rural site in the Sierra Nevada Mountains of Northern California. Nucleation events in the winter of 2009 occurred during two pristine periods following precipitation, with higher gas-phase SO(2) concentrations during the second period, when faster particle growth occurred (7-8 nm/h). Amines, as opposed to ammonia, and sulfate were detected in the particle phase throughout new particle formation (NPF) events, increasing in number as the particles grew to larger sizes. Interestingly, long-range transport of SO(2) from Asia appeared to potentially play a role in NPF during faster particle growth. Understanding the propensity of newly formed particles to act as CCN is critical for predicting the effects of NPF on orographic cloud formation during winter storms along the Sierra Nevada Mountain range. The potential impact of newly formed particles in remote regions needs to be compared with that of transported urban aerosols when evaluating the impact of aerosols on clouds and climate.

  9. Source tracking aerosols released from land-applied class B biosolids during high-wind events.

    PubMed

    Baertsch, Carolina; Paez-Rubio, Tania; Viau, Emily; Peccia, Jordan

    2007-07-01

    DNA-based microbial source tracking (MST) methods were developed and used to specifically and sensitively track the unintended aerosolization of land-applied, anaerobically digested sewage sludge (biosolids) during high-wind events. Culture and phylogenetic analyses of bulk biosolids provided a basis for the development of three different MST methods. They included (i) culture- and 16S rRNA gene-based identification of Clostridium bifermentans, (ii) direct PCR amplification and sequencing of the 16S rRNA gene for an uncultured bacterium of the class Chloroflexi that is commonly present in anaerobically digested biosolids, and (iii) direct PCR amplification of a 16S rRNA gene of the phylum Euryarchaeota coupled with terminal restriction fragment length polymorphism to distinguish terminal fragments that are unique to biosolid-specific microorganisms. Each method was first validated with a broad group of bulk biosolids and soil samples to confirm the target's exclusive presence in biosolids and absence in soils. Positive responses were observed in 100% of bulk biosolid samples and in less than 11% of the bulk soils tested. Next, a sampling campaign was conducted in which all three methods were applied to aerosol samples taken upwind and downwind of fields that had recently been land applied with biosolids. When average wind speeds were greater than 5 m/s, source tracking results confirmed the presence of biosolids in 56% of the downwind samples versus 3% of the upwind samples. During these high-wind events, the biosolid concentration in downwind aerosols was between 0.1 and 2 microg/m3. The application of DNA-based source tracking to aerosol samples has confirmed that wind is a possible mechanism for the aerosolization and off-site transport of land-applied biosolids. PMID:17513591

  10. Stratospheric aerosol modification by supersonic transport operations with climate implications

    NASA Technical Reports Server (NTRS)

    Toon, O. B.; Turco, R. P.; Pollack, J. B.; Whitten, R. C.; Poppoff, I. G.; Hamill, P.

    1980-01-01

    The potential effects on stratospheric aerosois of supersonic transport emissions of sulfur dioxide gas and submicron size soot granules are estimated. An interactive particle-gas model of the stratospheric aerosol is used to compute particle changes due to exhaust emissions, and an accurate radiation transport model is used to compute the attendant surface temperature changes. It is shown that a fleet of several hundred supersonic aircraft, operating daily at 20 km, could produce about a 20% increase in the concentration of large particles in the stratosphere. Aerosol increases of this magnitude would reduce the global surface temperature by less than 0.01 K.

  11. Modelling of primary aerosols in the chemical transport model MOCAGE: development and evaluation of aerosol physical parameterizations

    NASA Astrophysics Data System (ADS)

    Sič, B.; El Amraoui, L.; Marécal, V.; Josse, B.; Arteta, J.; Guth, J.; Joly, M.; Hamer, P.

    2014-04-01

    This paper deals with recent improvements to the chemical transport model of Météo-France MOCAGE that consists of updates to different aerosol parameterizations. MOCAGE only contains primary aerosol species. We introduced important changes to the aerosol parameterization concerning emissions, wet deposition and sedimentation. For the emissions, size distribution and wind calculations are modified for desert dust aerosols, and a surface sea temperature dependant source function is introduced for sea salt aerosols. Wet deposition is modified toward a more physically realistic representation by introducing re-evaporation of falling rain and snowfall scavenging, and by changing in-cloud scavenging scheme along with calculations of precipitation cloud cover and rain properties. The sedimentation scheme update includes changes regarding the stability and viscosity calculations. Independent data from satellites (MODIS, SEVIRI), the ground (AERONET), and a model inter-comparison project (AeroCom) is compared with MOCAGE simulations and showed that the introduced changes brought a significant improvement on aerosol representation, properties and global distribution. Emitted quantities of desert dust and sea salt, as well their lifetimes, moved closer towards values of AeroCom estimates and the multi-model average. When comparing the model simulations with MODIS aerosol optical depth (AOD) observations over the oceans, the updated model configuration shows a decrease in the bias (from 0.032 to 0.002) and a better correlation (from 0.062 to 0.322) in terms of the geographical distribution and the temporal variability. The updates corrected a strong positive bias in the sea salt representation at high latitudes (from 0.153 to 0.026), and a negative bias in the desert dust representation in the African dust outflow region (from -0.179 to -0.051). The updates in sedimentation produced a modest difference; the bias with MODIS data from 0.002 in the updated configuration went to

  12. The Cloud-Aerosol Transport System (CATS): a New Lidar for Aerosol and Cloud Profiling from the International Space Station

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; McGill, Matthew J.; Yorks, John E.; Hlavka, Dennis L.; Hart, William D.; Palm, Stephen P.; Colarco, Peter R.

    2011-01-01

    Spaceborne lidar profiling of aerosol and cloud layers has been successfully implemented during a number of prior missions, including LITE, ICESat, and CALIPSO. Each successive mission has added increased capability and further expanded the role of these unique measurements in wide variety of applications ranging from climate, to air quality, to special event monitoring (ie, volcanic plumes). Many researchers have come to rely on the availability of profile data from CALIPSO, especially data coincident with measurements from other A-Train sensors. The CALIOP lidar on CALIPSO continues to operate well as it enters its fifth year of operations. However, active instruments have more limited lifetimes than their passive counterparts, and we are faced with a potential gap in lidar profiling from space if the CALIOP lidar fails before a new mission is operational. The ATLID lidar on EarthCARE is not expected to launch until 2015 or later, and the lidar component of NASA's proposed Aerosols, Clouds, and Ecosystems (ACE) mission would not be until after 2020. Here we present a new aerosol and cloud lidar that was recently selected to provide profiling data from the International Space Station (ISS) starting in 2013. The Cloud-Aerosol Transport System (CATS) is a three wavelength (1064, 532, 355 nm) elastic backscatter lidar with HSRL capability at 532 nm. Depolarization measurements will be made at all wavelengths. The primary objective of CATS is to continue the CALIPSO aerosol and cloud profile data record, ideally with overlap between both missions and EarthCARE. In addition, the near real time data capability of the ISS will enable CATS to support operational applications such as air quality and special event monitoring. The HSRL channel will provide a demonstration of technology and a data testbed for direct extinction retrievals in support of ACE mission development. An overview of the instrument and mission will be provided, along with a summary of the science

  13. Intercontinental Transport of Aerosols: Implication for Regional Air Quality

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Ginoux, Paul

    2006-01-01

    Aerosol particles, also known as PM2.5 (particle diameter less than 2.5 microns) and PM10 (particle diameter less than 10 microns), is one of the key atmospheric components that determine ambient air quality. Current US air quality standards for PM10 (particles with diameter < 10 microns) and PM2.5 (particles with diameter 2.5 microns) are 50 pg/cu m and 15 pg/cu m, respectively. While local and regional emission sources are the main cause of air pollution problems, aerosols can be transported on a hemispheric or global scale. In this study, we use the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model to quantify contributions of long-range transport vs. local/regional pollution sources and from natural vs. anthropogenic sources to PM concentrations different regions. In particular, we estimate the hemispheric impact of anthropogenic sulfate aerosols and dust from major source areas on other regions in the world. The GOCART model results are compared with satellite remote sensing and ground-based network measurements of aerosol optical depth and concentrations.

  14. Characteristics of aerosol optical properties and meteorological parameters during three major dust events (2005-2010) over Beijing, China

    NASA Astrophysics Data System (ADS)

    Cao, Chunxiang; Zheng, Sheng; Singh, Ramesh P.

    2014-12-01

    Multi-satellite sensors are capable of monitoring transport and characteristics of dust storms and changes in atmospheric parameters along their transport. The present paper discusses aerosol optical properties and meteorological parameters during major dust storm events occurred in the period 2005-2010 over Beijing, China. The back trajectory model shows that the dust is transported from the Inner Mongolia and Mongolia arid regions to Beijing. High aerosol optical depth (AOD) at the wavelength 675 nm and low Ångström exponent (AE) values in the wavelength 440-870 nm are observed during dusty days. The aerosol size distribution (ASD) in coarse mode shows a large increase in the volume during dusty days. The single scattering albedo (SSA) increases with higher wavelength on dusty days, and is generally found to be higher compared to the days prior to and after the dust events, indicating the presence of high concentrations of scattering particles due to dust storm events. The physico-chemical properties of aerosols during dusty and non dusty days show distinct characteristics as reflected from the changes in the real and imaginary parts of refractive index (RI). In addition, the CO volume mixing ratio (COVMR) from Atmospheric Infrared Sounder (AIRS) shows a pronounced decrease on dusty days, while the H2O mass mixing ratio (H2OMMR) shows enhanced signal. Furthermore, enhanced level of water vapor (WV) using Moderate Resolution Imaging Spectroradiometer (MODIS) data is also observed in and around Beijing over the dust storms track.

  15. Synoptic-scale dust transport events in the southern Himalaya

    NASA Astrophysics Data System (ADS)

    Duchi, R.; Cristofanelli, P.; Marinoni, A.; Bourcier, L.; Laj, P.; Calzolari, F.; Adhikary, B.; Verza, G. P.; Vuillermoz, E.; Bonasoni, P.

    2014-06-01

    The variability of long-range dust transport events observed in the southern Himalaya and its relation with source areas have been studied thanks to five years’ continuous measurements which were carried out at the “Nepal Climate Observatory-Pyramid” (NCO-P, 27°57‧N, 86°48‧E), the highest Northern Hemisphere GAW-WMO global station sited at 5079 m a.s.l. in the high Khumbu valley (Nepal) on the southern Himalaya. During the period March 2006-February 2011, the analyses of the aerosol particle concentrations and LAGRANTO three-dimensional backward trajectories indicated the occurrence of 275 days affected by synoptic-scale dust transport, which account for 22.2% of the investigated period. The frequency of dust transport days (DTDs) showed a clear seasonal cycle, with the highest seasonal value observed during pre-monsoon season (33.5% of the pre-monsoon’s days are DTDs). Large enhancements in coarse aerosol number concentration N1-10 (average: +689%) and mass PM1-10 (average: +1086%) were observed during the dust transport events as compared to the days without dust (dust-free days, DFDs). In addition, the single scattering albedo (SSA) also showed higher values, ranging from 0.87 to 0.90, during DTDs with respect to DFDs (0.80-0.87). The predominant source of mineral dust reaching the measurement site was identified in the arid regions of the north-western Indian subcontinent (Thar desert), which accounted for 41.6% of the trajectories points associated with DTDs. Seasonal analysis also indicated that the winter season was significantly influenced by far western desert regions, such as North Africa and the Arabic Peninsula.

  16. Modelling the optical properties of aerosols in a chemical transport model

    NASA Astrophysics Data System (ADS)

    Andersson, E.; Kahnert, M.

    2015-12-01

    According to the IPCC fifth assessment report (2013), clouds and aerosols still contribute to the largest uncertainty when estimating and interpreting changes to the Earth's energy budget. Therefore, understanding the interaction between radiation and aerosols is both crucial for remote sensing observations and modelling the climate forcing arising from aerosols. Carbon particles are the largest contributor to the aerosol absorption of solar radiation, thereby enhancing the warming of the planet. Modelling the radiative properties of carbon particles is a hard task and involves many uncertainties arising from the difficulties of accounting for the morphologies and heterogeneous chemical composition of the particles. This study aims to compare two ways of modelling the optical properties of aerosols simulated by a chemical transport model. The first method models particle optical properties as homogeneous spheres and are externally mixed. This is a simple model that is particularly easy to use in data assimilation methods, since the optics model is linear. The second method involves a core-shell internal mixture of soot, where sulphate, nitrate, ammonia, organic carbon, sea salt, and water are contained in the shell. However, by contrast to previously used core-shell models, only part of the carbon is concentrated in the core, while the remaining part is homogeneously mixed with the shell. The chemical transport model (CTM) simulations are done regionally over Europe with the Multiple-scale Atmospheric Transport and CHemistry (MATCH) model, developed by the Swedish Meteorological and Hydrological Institute (SMHI). The MATCH model was run with both an aerosol dynamics module, called SALSA, and with a regular "bulk" approach, i.e., a mass transport model without aerosol dynamics. Two events from 2007 are used in the analysis, one with high (22/12-2007) and one with low (22/6-2007) levels of elemental carbon (EC) over Europe. The results of the study help to assess the

  17. 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.

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

    PubMed

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

    2014-05-01

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

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

    PubMed

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

    2014-05-01

    Workplace air monitoring programs for sampling radioactive aerosols in nuclear facilities sometimes must rely on sampling systems to move the air to a sample filter in a safe and convenient location. These systems may consist of probes, straight tubing, bends, contractions and other components. Evaluation of these systems for potential loss of radioactive aerosols is important because significant losses can occur. However, it can be very difficult to find fully described equations to model a system manually for a single particle size and even more difficult to evaluate total system efficiency for a polydispersed particle distribution. Some software methods are available, but they may not be directly applicable to the components being evaluated and they may not be completely documented or validated per current software quality assurance requirements. This paper offers a method to model radioactive aerosol transport in sampling systems that is transparent and easily updated with the most applicable models. Calculations are shown with the R Programming Language, but the method is adaptable to other scripting languages. The method has the advantage of transparency and easy verifiability. This paper shows how a set of equations from published aerosol science models may be applied to aspiration and transport efficiency of aerosols in common air sampling system components. An example application using R calculation scripts is demonstrated. The R scripts are provided as electronic attachments. PMID:24667389

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  1. The Cloud-Aerosol Transport System (CATS): Demonstrating New Techniques for Cloud and Aerosol Measurements

    NASA Astrophysics Data System (ADS)

    Yorks, J. E.; McGill, M. J.; Palm, S. P.; Hlavka, D. L.; Nowottnick, E. P.; Selmer, P. A.

    2015-12-01

    The Cloud-Aerosol Transport System (CATS) is an elastic backscatter lidar that provides vertical profiles of cloud and aerosol properties. The CATS payload has been operating since early February 2015 from the International Space Station (ISS). CATS was designed to operate for six months, and up to three years, providing a combination of operational science, in-space technology demonstration, and technology risk reduction for future Earth Science missions. One of the primary project goals of CATS is to demonstrate technology in support of future space-based lidar mission development. The CATS instrument has been demonstrating the high repetition rate laser and photon counting detection approach to lidar observations, in contrast to the low repetition rate, high energy technique employed by CALIPSO. Due to this technique, cloud and aerosol profile data exhibit high spatial and temporal resolution, which was never before possible from a space-based platform. Another important science goal of the CATS-FO project is accurate determination of aerosol type on a global scale. CATS provided the first space-based depolarization measurements at multiple wavelengths (532 and 1064 nm), and first measurements at 1064 nm from space. The ratio of the depolarization measurements at these two wavelengths enables significant improvement in aerosol typing. The CATS retrievals at 1064 nm also provide improvements to detecting aerosols above clouds. The CATS layer identification algorithm is a threshold-based layer detection method that uses the 1064 nm attenuated scattering ratio and also includes a routine to identify clouds embedded within aerosol layers. This technique allows CATS to detect the full extent of the aerosol layers above the cloud, and differentiate these two layers so that the optical properties can be more accurately determined.

  2. Chemical and Aerosol Signatures of Biomass Burning via Long Range Transport observed at Storm Peak Laboratory

    NASA Astrophysics Data System (ADS)

    Hallar, A. G.; Obrist, D.; McCubbin, I. B.; Fain, X.; Rahn, T.

    2008-12-01

    The Desert Research Institute operates a high elevation facility, Storm Peak Laboratory (SPL), located on the Steamboat Springs Ski Resort in Colorado at an elevation 3.2 km. During the spring of 2008, two field projects were conducted at SPL; Storm Peak Cloud and Aerosol Characterization (SPACC) and a State of Colorado Mercury Monitoring project. Measurements of gaseous elemental mercury (GEM), along with CO, ozone and aerosol concentrations and aerosol size distributions will be presented from April 28 to July 1st 2008. This work focuses on specific case studies pertaining to long range transport events. Specifically, high levels of GEM and CO will be presented from May 15, 2008. This data will be coupled with HYSPLIT backtrajectories, chemical modeling via MOZART, and satellite imagery (MODIS) to present evidence that Siberian wildfires impacted the air quality at Storm Peak Laboratory.

  3. Lidar and sunphotometry observations on the long-range transport of smoke and dust events

    NASA Astrophysics Data System (ADS)

    Strawbridge, K. B.; Thulasiraman, S.; O'Neill, N. T.; McKendry, I. G.

    2006-09-01

    The remote sensing techniques of Lidar and Sunphotometry are well suited for understanding the optical characteristics of aerosol layers aloft. Lidar has the ability to detect the complex vertical structure of the atmosphere and can therefore identify the existence and extent of aerosols that have undergone long-range transport. Inversion techniques applied to Sunphotometry data can extract information about the aerosol fine and coarse modes. As part of the REALM network (Regional East Atmospheric Lidar Mesonet), routine measurements are made with a vertically-pointing lidar at the Centre For Atmospheric Research Experiments (CARE). In addition, a CIMEL sunphotometer resides at CARE (part of AERONET) yielding an opportunity to achieve an optical climatology of aerosol activity over the site. Environment Canada's mobile lidar facility called RASCAL (Rapid Acqusition SCanning Aerosol Lidar), operating in zenith mode only, was also deployed to Western Canada during the months of March and April, 2005 to provide an opportunity to measure the long-range transport of trans-Pacific pollutants that impact the coastal areas of British Columbia frequently. During that time a long-range transport event was observed on 13-14 of March 2005. Further analysis has shown the event originated from North African dust storms during the period 28 February to 3 March. The optical coherency of these active and passive remote sensors will be presented, along with other supporting observations, for forest fire smoke plumes transported over CARE (in 2003) and the first documented case of Saharan dust to impact Western North America.

  4. The conservative characteristic FD methods for atmospheric aerosol transport problems

    NASA Astrophysics Data System (ADS)

    Fu, Kai; Liang, Dong

    2016-01-01

    In the paper, we develop the new conservative characteristic finite difference methods (C-CFD) for the atmospheric aerosol transport problems. We propose the time second-order and spatial high-order conservative characteristic finite difference methods for the aerosol vertical advection-diffusion process and the two-dimensional conservative characteristic finite difference methods for aerosol horizontal transport process in the second-order splitting algorithm. Based on the characteristic form of advection-diffusion equations tracking back along the characteristic curve, we treat the integrals over the tracking cells at the previous time level by the conservative interpolations and propose to treat the diffusion terms by the average along the characteristics, where the high-order discrete fluxes are obtained by approximating the cumulative mass function and are continuous at the tracking points. The important feature is that the proposed C-CFD schemes preserve mass and have second-order accuracy in time and high-order accuracy in space. Numerical tests are taken to show the accuracy in time and space and mass conservation of our C-CFD schemes, compared with the standard CFD method. A real case of air quality modelling during the 2008 Beijing Olympics and a severe haze in North China are further simulated and analyzed by using our C-CFD algorithm. Simulated results are in good agreement with observations. The developed C-CFD algorithm can be used for efficiently solving large scale atmospheric aerosol transport problems.

  5. Aerosol Plume during a Polluted Event Occuring Over Paris Area and its Potential Photochemical Effect

    NASA Astrophysics Data System (ADS)

    Randriamiarisoa, H.; Chazette, P.; Sanak, J.; Hauglustaine, D.

    2002-12-01

    As in many big cities, there are several pollution events in Paris area. A thorough understanding of the processes leading on the formation of pollutants and their transport during pollution episodes is necessary. One of the pertinent factors, which contributions on atmospheric chemistry and radiative effect are not yet well known, is the aerosol. ESQUIF (Etude et Simulation de la QUalité de l?air en Ile de France) is the first program dedicated to study such issues over the Paris area. It was carried out from summer 1998 to winter 2000 (Menut et al., 2000). To characterize all the properties of the urban aerosol, many campaigns were coordinated using both ground and airborne measurements (Chazette et al., 2000). We are focusing on the 31st of July 2000 where a well-defined polluted plume has been observed. Aerosol number concentrations in different size classes were measured and show that urban aerosol in Paris area is mainly submicronic. The absorbent part of the aerosol, mainly associated to the black carbon component, has been observed to be associated to particles with diameter less than 0.1 æm. The single scattering albedo has been assessed to be close to 0.85 leading to a significant influence on the photochemical chemistry. Indeed, a significant decrease of the daily maximum ozone concentration has been calculated using the INCA model and will be presented. ACKNOWLEDGEMENTS The Programme National de Chimie Atmosphérique, INSU supported this work. REFERENCES Chazette P., H. Randriamiarisoa, J. Sanak, C. Flamant, J. Pelon, M. Sicard, H. Cachier, F. Aulagnier, R. Sarda-Esteve, L. Gomes, S. Alfaro and A. Gaudichet (2001). ESQUIF 2000 : Aerosol survey over the Ile-de-France area, J. Aerosol Sci ., 32/suppl. 1, S439-S440. Menut, L., R. Vautard, C. Flamant, A. Abonnel, M. Beekmann, P. Chazette, P.H. Flamant, D. Gombert, D. Guédalia, D. Kley, M.P. Lefebvre, B. Lossec, D. Martin, G. Mégie, P. Perros, M. Sicard and G. Toupance (2000). Measurements and modelling

  6. Unique DNA-barcoded aerosol test particles for studying aerosol transport

    DOE PAGES

    Harding, Ruth N.; Hara, Christine A.; Hall, Sara B.; Vitalis, Elizabeth A.; Thomas, Cynthia B.; Jones, A. Daniel; Day, James A.; Tur-Rojas, Vincent R.; Jorgensen, Trond; Herchert, Edwin; et al

    2016-03-22

    Data are presented for the first use of novel DNA-barcoded aerosol test particles that have been developed to track the fate of airborne contaminants in populated environments. Until DNATrax (DNA Tagged Reagents for Aerosol eXperiments) particles were developed, there was no way to rapidly validate air transport models with realistic particles in the respirable range of 1–10 μm in diameter. The DNATrax particles, developed at Lawrence Livermore National Laboratory (LLNL) and tested with the assistance of the Pentagon Force Protection Agency, are the first safe and effective materials for aerosol transport studies that are identified by DNA molecules. The usemore » of unique synthetic DNA barcodes overcomes the challenges of discerning the test material from pre-existing environmental or background contaminants (either naturally occurring or previously released). The DNATrax particle properties are demonstrated to have appropriate size range (approximately 1–4.5 μm in diameter) to accurately simulate bacterial spore transport. As a result, we describe details of the first field test of the DNATrax aerosol test particles in a large indoor facility.« less

  7. Aerosol transport from Chiang Mai, Thailand to Mt. Lulin, Taiwan - Implication of aerosol aging during long-range transport

    NASA Astrophysics Data System (ADS)

    Chuang, Ming-Tung; Lee, Chung-Te; Chou, Charles C.-K.; Engling, Guenter; Chang, Shih-Yu; Chang, Shuenn-Chin; Sheu, Guey-Rong; Lin, Neng-Huei; Sopajaree, Khajornsak; Chang, You-Jia; Hong, Guo-Jun

    2016-07-01

    The transport of biomass burning (BB) aerosol from Indochina may cause a potential effect on climate change in Southeast Asia, East Asia, and the Western Pacific. Up to now, the understanding of BB aerosol composition modification during long-range transport (LRT) is still very limited due to the lack of observational data. In this study, atmospheric aerosols were collected at the Suthep/Doi Ang Khang (DAK) mountain sites in Chiang Mai, Thailand and the Lulin Atmospheric Background Station (Mt. Lulin) in central Taiwan from March to April 2010 and from February to April 2013, respectively. During the study period, an upwind and downwind relationship between the Suthep/DAK and Lulin sites (2400 km apart) was validated by backward trajectories. Comprehensive aerosol properties were resolved for PM2.5 water-soluble inorganic ions, carbonaceous content, water-soluble/insoluble organic carbon (WSOC/WIOC), dicarboxylic acids and their salts (DCAS), and anhydrosugars. A Modification Factor (MF) is proposed by employing non-sea-salt potassium ion (nss-K+) or fractionalized elemental carbon evolved at 580 °C after pyrolized OC correction (EC1-OP) as a BB aerosol tracer to evaluate the mass fraction changes of aerosol components from source to receptor regions during LRT. The MF values of nss-SO42-, NH4+, NO3-, OC1 (fractionalized organic carbon evolved from room temperature to 140 °C), OP (pyrolized OC fraction), DCAS, and WSOC were above unity, which indicated that these aerosol components were enhanced during LRT as compared with those in the near-source region. In contrast, the MF values of anhydrosugars ranged from 0.1 to 0.3, indicating anhydrosugars have degraded during LRT.

  8. Electron Microanalysis of Aerosols Collected at Mauna Loa Observatory During an Asian Dust Storm Event

    NASA Astrophysics Data System (ADS)

    Conny, J. M.; Willis, R. D.; Ortiz-Montalvo, D. L.; Colton, A.

    2014-12-01

    Located in the remote marine free troposphere, the Mauna Loa Observatory (MLO) represents a clean airshed that can be used to study anthropogenic pollution influences and long-range transport of aerosol particles from the Asian mainland. Because of the global nature of Asian dust storms, the radiative properties of these particles transported long-range can significantly impact global climate. It has been proposed that aerosols transported to MLO during upslope wind conditions (typically daytime) are local in origin while aerosols transported during downslope conditions (typically nighttime) represent long-range transport in the free troposphere. Twelve PM10 samples (six daytime/nightime pairs) were collected on polycarbonate filters for 72 hours each between March 15 and April 26, 2011. Bulk samples of dust from local sources (road dust, parking lot, lava fields) were collected as well in order to assess the PM10 contribution from local dusts. On March 19-20 the Korea Meteorological Administration documented a significant dust event over the Korean peninsula. Back-trajectory analyses from MLO coupled with local wind speed and wind direction data suggest that this dust event may have been captured during the MLO sampling campaign. MLO samples were analyzed by computer-controlled scanning electron microscopy (CCSEM) coupled with energy-dispersive X-ray spectrometry (EDX) and particles were sorted into compositionally-distinct particle types which were then compared across the sample set. Concentrations of particle types expected to be associated with Asian dust were observed to peak in one pair of daytime/nighttime samples collected between March 22 and March 28. Manual microscopic characterization of suspected Asian dust particles and local dust particles was carried out using electron backscatter diffraction (EBSD) in conjunction with EDX and focussed ion beam SEM (FIB-SEM) in an effort to characterize differences in physicochemical or radiative properties of

  9. Satellite and ground-based remote sensing of aerosols during intense haze event of October 2013 over lahore, Pakistan

    NASA Astrophysics Data System (ADS)

    Tariq, Salman; Zia, ul-Haq; Ali, Muhammad

    2016-02-01

    Due to increase in population and economic development, the mega-cities are facing increased haze events which are causing important effects on the regional environment and climate. In order to understand these effects, we require an in-depth knowledge of optical and physical properties of aerosols in intense haze conditions. In this paper an effort has been made to analyze the microphysical and optical properties of aerosols during intense haze event over mega-city of Lahore by using remote sensing data obtained from satellites (Terra/Aqua Moderate-resolution Imaging Spectroradiometer (MODIS) and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO)) and ground based instrument (AErosol RObotic NETwork (AERONET)) during 6-14 October 2013. The instantaneous highest value of Aerosol Optical Depth (AOD) is observed to be 3.70 on 9 October 2013 followed by 3.12 on 8 October 2013. The primary cause of such high values is large scale crop residue burning and urban-industrial emissions in the study region. AERONET observations show daily mean AOD of 2.36 which is eight times higher than the observed values on normal day. The observed fine mode volume concentration is more than 1.5 times greater than the coarse mode volume concentration on the high aerosol burden day. We also find high values (~0.95) of Single Scattering Albedo (SSA) on 9 October 2013. Scatter-plot between AOD (500 nm) and Angstrom exponent (440-870 nm) reveals that biomass burning/urban-industrial aerosols are the dominant aerosol type on the heavy aerosol loading day over Lahore. MODIS fire activity image suggests that the areas in the southeast of Lahore across the border with India are dominated by biomass burning activities. A Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model backward trajectory showed that the winds at 1000 m above the ground are responsible for transport from southeast region of biomass burning to Lahore. CALIPSO derived sub-types of

  10. Fungal Spore Concentrations and Ergosterol Content in Aerosol Samples in the Caribbean During African Dust Events

    NASA Astrophysics Data System (ADS)

    Santos-Figueroa, G.; Bolaños-Rosero, B.; Mayol-Bracero, O. L.

    2015-12-01

    Fungal spores are a major component of primary biogenic aerosol particles that are emitted to the atmosphere, are ubiquitous, and play an important role in the chemistry and physics of the atmosphere, climate, and public health. Every year, during summer months, African dust (AD) particles are transported to the Caribbean region causing an increase in the concentrations of particulate matter in the atmosphere. AD is one of the most important natural sources of mineral particulate matter at the global scale, and many investigations suggest that it has the ability to transport dust-associated biological particles through long distances. The relationship between AD incursions and the concentration of fungal spores in the Caribbean region is poorly understood. In order to investigate the effects of AD incursions on fungal spore's emissions, fungal spore concentrations were monitored using a Burkard spore trap at the tropical montane cloud forest of Pico del Este at El Yunque National Forest, Puerto Rico. The presence of AD was supported with satellite images of aerosol optical thickness, and with the results from the air masses backward trajectories calculated with the NOAA HYSPLIT model. Basidiospores and Ascospores comprised the major components of the total spore's concentrations, up to a maximum of 98%, during both AD incursions and background days. A considerably decrease in the concentration of fungal spores during AD events was observed. Ergosterol, biomarker for measuring fungal biomass, concentrations were determined in aerosols that were sampled at a marine site, Cabezas de San Juan Nature Reserve, in Fajardo Puerto Rico, and at an urban site, Facundo Bueso building at the University of Puerto Rico. Additional efforts to understand the relationship between the arrival of AD to the Caribbean and a decrease in spore's concentrations are needed in order to investigate changes in local spore's vs the contribution of long-range spores transported within the AD.

  11. Differences in Fine- Coarse Aerosol Ratios in Convective and Non-Convective Dust Events in a Desert City

    NASA Astrophysics Data System (ADS)

    Gill, T. E.; Rivera Rivera, N. I.; Novlan, D. J.

    2014-12-01

    El Paso, Texas (USA) and Ciudad Juarez, Chihuahua (Mexico) form the Paso del Norte, the largest metropolitan area in North America's Chihuahuan Desert. The cities are subject to frequent dust storms presenting a hazard to local infrastructure and health, including synoptic-scale dust events during winter and spring, and dusty outflows from convective storms (haboobs) primarily during the summer. We evaluate particulate matter (PM2.5 and PM10) concentrations over a decade of convective and non-convective dust events, based on hourly aerosol data collected by Texas Commission on Environmental Quality (TCEQ) continuous air monitors in El Paso cross-referenced to weather observations from the USA National Weather Service. A total of 219 dust events (95 convective and 124 non-convective) events occurred between 2001 and 2010. The PM2.5/PM10 ratio was significantly higher (proportionally greater concentration of fine aerosols) in convective episodes and during summertime events than during non-convective dust events and dust episodes in other seasons, although overall concentrations of both PM2.5 and PM10 were higher in the non-convective events, which were also longer-lasting. These differences in fine/coarse aerosol ratios are likely related to different atmospheric stability conditions, and/or different mechanisms of dust particle entrainment and transport in haboobs versus non-convective dust events. Since visibility degradation and adverse human health effects are known to be exacerbated by to fine aerosol concentrations, thunderstorm-related dust events may present a proportionally greater hazard.

  12. The Cloud-Aerosol Transport System (CATS): A New Lidar for Aerosol and Cloud Profiling from the International Space Station

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; McGill, Mathew J.; Yorks. John E.; Hlavka, Dennis L.; Hart, William D.; Palm, Stephen P.; Colarco, Peter R.

    2012-01-01

    Spaceborne lidar profiling of aerosol and cloud layers has been successfully implemented during a number of prior missions, including LITE, ICESat, and CALIPSO. Each successive mission has added increased capability and further expanded the role of these unique measurements in wide variety of applications ranging from climate, to air quality, to special event monitoring (ie, volcanic plumes). Many researchers have come to rely on the availability of profile data from CALIPSO, especially data coincident with measurements from other A-Train sensors. The CALIOP lidar on CALIPSO continues to operate well as it enters its fifth year of operations. However, active instruments have more limited lifetimes than their passive counterparts, and we are faced with a potential gap in lidar profiling from space if the CALIOP lidar fails before a new mission is operational. The ATLID lidar on EarthCARE is not expected to launch until 2015 or later, and the lidar component of NASA's proposed Aerosols, Clouds, and Ecosystems (ACE) mission would not be until after 2020. Here we present a new aerosol and cloud lidar that was recently selected to provide profiling data from the International Space Station (ISS) starting in 2013. The Cloud-Aerosol Transport System (CATS) is a three wavelength (1064,532,355 nm) elastic backscatter lidar with HSRL capability at 532 nm. Depolarization measurements will be made at all wavelengths. The primary objective of CATS is to continue the CALIPSO aerosol and cloud profile data record, ideally with overlap between both missions and EarthCARE. In addition, the near real time (NRT) data capability ofthe ISS will enable CATS to support operational applications such as aerosol and air quality forecasting and special event monitoring. The HSRL channel will provide a demonstration of technology and a data testbed for direct extinction retrievals in support of ACE mission development. An overview of the instrument and mission will be provided, along with a

  13. Evolution of a Canadian biomass burning aerosol smoke plume transported to the U.S. East Coast

    NASA Astrophysics Data System (ADS)

    Miller, D. J.; Sun, K.; Zondlo, M. A.; Kanter, D.; Ginoux, P. A.

    2010-12-01

    We synthesize ground-based and satellite measurements to track the physical and chemical evolution of a biomass burning aerosol plume emitted in central Canada as it was transported to the U.S. East Coast. Biomass burning emissions strongly influence both air quality and radiative processes through trace gas and aerosol emissions. Organic carbon and black carbon smoke aerosols can be transported long distances downwind of the emissions source region. In some cases, biomass burning aerosol emissions have larger impacts than anthropogenic emissions, with implications for human health and aerosol radiative forcing on climate. Boreal forest fires in Canada on July 4, 2006 led to significant smoke aerosol emissions that were transported in layers at different altitudes over the Great Lakes to the northeastern United States. We track the aerosol plume with space-borne remote sensing satellite instrument (MODIS, OMI, MISR and CALIOP lidar) data as well as ground-based in-situ and remote aerosol observations (AERONET CIMEL sky/sun photometer, MPLNET lidar, IMPROVE and EPA AirNow). Combining total column, surface and vertical profile observations, we illustrate how plume altitude can affect spatial and temporal transport as well as optical and chemical properties. Convective lofting elevated smoke emissions above the boundary layer into the free troposphere (~3 km altitude) where higher speed winds led to rapid, long-range upper level transport to the Atlantic Ocean in 4-5 days. A lower aerosol layer led to enhancements in surface fine particulate matter (PM-2.5) mass concentrations accompanied by changes in aerosol composition as the plume mixed with anthropogenic sulfate aerosols. The extensive coverage of this smoke plume over the U.S. East Coast, a heavily populated region known for high anthropogenic aerosol loadings, significantly influenced regional air quality. Average PM-2.5 concentrations across Pennsylvania exceeded the U.S. EPA 24-hour PM-2.5 standard by 20.37

  14. Code System to Calculate Particle Penetration Through Aerosol Transport Lines.

    1999-07-14

    Version 00 Distribution is restricted to US Government Agencies and Their Contractors Only. DEPOSITION1.03 is an interactive software program which was developed for the design and analysis of aerosol transport lines. Models are presented for calculating aerosol particle penetration through straight tubes of arbitrary orientation, inlets, and elbows. An expression to calculate effective depositional velocities of particles on tube walls is derived. The concept of maximum penetration is introduced, which is the maximum possible penetrationmore » through a sampling line connecting any two points in a three-dimensional space. A procedure to predict optimum tube diameter for an existing transport line is developed. Note that there is a discrepancy in this package which includes the DEPOSITION 1.03 executable and the DEPOSITION 2.0 report. RSICC was unable to obtain other executables or reports.« less

  15. Uranium Oxide Aerosol Transport in Porous Graphite

    SciTech Connect

    Blanchard, Jeremy; Gerlach, David C.; Scheele, Randall D.; Stewart, Mark L.; Reid, Bruce D.; Gauglitz, Phillip A.; Bagaasen, Larry M.; Brown, Charles C.; Iovin, Cristian; Delegard, Calvin H.; Zelenyuk, Alla; Buck, Edgar C.; Riley, Brian J.; Burns, Carolyn A.

    2012-01-23

    The objective of this paper is to investigate the transport of uranium oxide particles that may be present in carbon dioxide (CO2) gas coolant, into the graphite blocks of gas-cooled, graphite moderated reactors. The transport of uranium oxide in the coolant system, and subsequent deposition of this material in the graphite, of such reactors is of interest because it has the potential to influence the application of the Graphite Isotope Ratio Method (GIRM). The GIRM is a technology that has been developed to validate the declared operation of graphite moderated reactors. GIRM exploits isotopic ratio changes that occur in the impurity elements present in the graphite to infer cumulative exposure and hence the reactor’s lifetime cumulative plutonium production. Reference Gesh, et. al., for a more complete discussion on the GIRM technology.

  16. Analysis of the Interaction and Transport of Aerosols with Cloud or Fog during DRAGON Campaigns in Asia from AERONET and Satellite Remote Sensing

    NASA Astrophysics Data System (ADS)

    Eck, Thomas; Holben, Brent; Reid, Jeffrey; Lynch, Peng; Schafer, Joel; Giles, David; Kim, Jhoon; Kim, Young; Sano, Itaru; Platnick, Steven; Arnold, George; Lyapustin, Alexei; Pickering, Kenneth; Crawford, James; Siniuk, Alexander; Smirnov, Alexander; Wang, Pucai; Xia, Xiangao; Li, Zhanqing

    2015-04-01

    Ground-based remote sensing observations from Aerosol Robotic Network (AERONET) sun-sky radiometers have recently shown several instances where cloud-aerosol interaction had resulted in modification of aerosol properties and/or in difficulty identifying some major pollution transport events due to aerosols being imbedded in cloud systems. AERONET has established Distributed Regional Aerosol Gridded Observation Networks (DRAGON) during field campaigns that are short-term (~2-3 months) relatively dense spatial networks of ~15 to 45 sun and sky scanning photometers. Major DRAGON field campaigns in Japan and South Korea during Spring of 2012 have yielded observations of aerosol transport associated with clouds and/or aerosol properties modification as a result of fog interaction. Analysis of data from the Korean and Japan DRAGON campaigns shows that major fine-mode aerosol transport events are sometimes associated with extensive cloud cover and that cloud-screening of observations often filter out significant pollution aerosol transport events. The Spectral De-convolution Algorithm (SDA) algorithm was utilized to isolate and analyze the fine-mode aerosol optical depth (AOD) signal from AERONET data for these cases of persistent and extensive cloud cover. Satellite retrievals of AOD from MODIS sensors (from both dark target and MAIAC algorithms) were also investigated to assess the issue of detectability of high AOD events associated with high cloud fraction. Cloud properties retrieved from MODIS are also investigated in relation to the AERONET and satellite measurements of AOD. Underestimation of AOD by the Navy Aerosol Analysis and Prediction System (NAAPS) model at very high AOD at sites in China and Korea was observed, especially for observations that are cloud screened by AERONET (L2 data). Additionally, extensive fog that was coincident with aerosol layer height on some days in Korea resulted in large increases in fine mode aerosol radius, with a mode of cloud

  17. Commuter exposure to aerosol pollution on public transport in Singapore

    NASA Astrophysics Data System (ADS)

    Tan, S.; Velasco, E.; Roth, M.; Norford, L.

    2013-12-01

    Personal exposure to aerosol pollutants in the transport microenvironment of Singapore has not been well documented. Studies from many cities suggest that brief periods of exposure to high concentrations of airborne pollutants may have significant health impacts. Thus, a large proportion of aerosol exposure may be experienced during daily commuting trips due to the proximity to traffic. A better understanding of the variability across transport modes is therefore needed to design transport policies that minimize commuters' exposure. In light of this, personal exposure measurements of PM10 and PM2.5, particle number (PN), black carbon (BC), carbon monoxide (CO), particle-bound polycyclic aromatic hydrocarbons (pPAH), and active surface area (SA) were conducted on a selected route in downtown Singapore. Portable and real-time monitoring instruments were carried onto three different modes of public transport (bus, taxi, subway) and by foot. Simultaneous measurements were taken at a nearby park to capture the background concentrations. Large variability was observed amongst the various transport modes investigated. For example, the particle number concentration was on average 1.5, 1.6, 0.8, and 2.2 times higher inside buses, taxis, subway and by foot, respectively, than at the background site. Based on the results, it is possible to come up with a ranking of the 'cleanest' transport mode for Singapore.

  18. Signatures of Biomass Burning Aerosols during a Smoke Plume Event from a Saltmarsh Wildfire in South Texas

    NASA Astrophysics Data System (ADS)

    Louchouarn, P.; Griffin, R. J.; Norwood, M. J.; Sterne, A. M. E.; Karakurt Cevik, B.

    2014-12-01

    The most conventional and abundant tracers of biomass combustion in aerosol particles include potassium and biomarkers derived from thermally altered cellulose/hemicellulose (anhydrosugars) and lignin (methoxyphenols). However, little is known of the role of biomass combustion as a particulate source of major plant polymers to the atmosphere. Here, concentrations of "free" (solvent-extractable) anhydrosugars and methoxyphenols are compared to the yields of polymeric lignin oxidation products (LOPs) during a smoke plume event in Houston, Texas. Downwind aerosol samples (PM2.5) were collected prior to, during, and following a two-day wildfire event that burned ~5,000 acres of a spartina saltmarsh ecosystem in the McFaddin National Wildlife Refuge, 125 km southeast of Houston. In addition, charcoals of the burned plants were collected within a week of the fire at the wildfire site. HYSPLIT modeling shows that Houston was directly downwind of this wildfire during the peak of the burn, with an approximate travel time from source to aerosol sampling site of 12-16 hrs. Concentrations of all organic markers, K+, and Ca2+ jumped by a factor of 2-13 within 1-2 days of the start of the fire and dropped to pre-fire levels three days after the peak event. Source signatures of anhydrosugars and free methoxyphenols during the peak of the plume were identical to those of grass charcoals collected from the site, confirming the potential use of charcoals as endmembers for source input reconstruction during atmospheric transport. An enrichment factor of 20 in the anhydrosugar to methoxyphenol ratio of aerosols vs. charcoals can partially be explained by differences in degradation rate constants between the two biomarker groups. Polymeric LOP comprised 73-91% of all lignin material in the aerosols, pointing to fires as major sources of primary biogenic aerosol particles and confirming an earlier study that lignin phenols in atmospheric particles occur predominantly in polymeric form.

  19. Size distribution and optical properties of mineral dust aerosols transported in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Denjean, C.; Cassola, F.; Mazzino, A.; Triquet, S.; Chevaillier, S.; Grand, N.; Bourrianne, T.; Momboisse, G.; Sellegri, K.; Schwarzenbock, A.; Freney, E.; Mallet, M.; Formenti, P.

    2016-02-01

    This study presents in situ aircraft measurements of Saharan mineral dust transported over the western Mediterranean basin in June-July 2013 during the ChArMEx/ADRIMED (the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) airborne campaign. Dust events differing in terms of source region (Algeria, Tunisia and Morocco), time of transport (1-5 days) and height of transport were sampled. Mineral dust were transported above the marine boundary layer, which conversely was dominated by pollution and marine aerosols. The dust vertical structure was extremely variable and characterized by either a single layer or a more complex and stratified structure with layers originating from different source regions. Mixing of mineral dust with pollution particles was observed depending on the height of transport of the dust layers. Dust layers carried a higher concentration of pollution particles below 3 km above sea level (a.s.l.) than above 3 km a.s.l., resulting in a scattering Ångström exponent up to 2.2 below 3 km a.s.l. However, the optical properties of the dust plumes remained practically unchanged with respect to values previously measured over source regions, regardless of the altitude. Moderate absorption of light by the dust plumes was observed with values of aerosol single scattering albedo at 530 nm ranging from 0.90 to 1.00. Concurrent calculations from the aerosol chemical composition revealed a negligible contribution of pollution particles to the absorption properties of the dust plumes that was due to a low contribution of refractory black carbon in regards to the fraction of dust and sulfate particles. This suggests that, even in the presence of moderate pollution, likely a persistent feature in the Mediterranean, the optical properties of the dust plumes could be assumed similar to those of native dust in radiative transfer simulations, modelling studies and satellite retrievals

  20. Evaluating global atmospheric transport of plutonium with dust aerosols

    NASA Astrophysics Data System (ADS)

    Velarde, R.; Arimoto, R.; Gill, T. E.; Kang, C.; Goodell, P.

    2009-12-01

    The resuspension of soils contaminated with radionuclides from nuclear weapons tests is a mechanism by which plutonium can be re-distributed throughout the environment. To better understand the global atmospheric transport of plutonium, we measured the activity of Pu in aerosol samples from four widely separated sites that receive dust from distant sources in both Asia and Africa. High-volume aerosol samples were collected from Barbados (2005 - 2006); Gosan, South Korea (2005 - 2006); Izaña, Canary Islands (1989 - 1996); and Mauna Loa Observatory, Hawaii (2005 - 2006) to evaluate the relationship between Pu activity and mineral dust concentrations (using crustal elements such as aluminum as a dust proxy). The activity of 239,240Pu (239Pu + 240Pu) in the aerosol samples was determined by alpha spectrometry following a series of chemical separations. Concentrations of other elements were determined by a variety of techniques. Pu activity was below the detection limit in many samples. In those samples where it was detected, the Gosan site had the highest dust concentrations and highest total plutonium activity, while Mauna Loa Observatory had the lowest dust concentrations and lowest 239,240Pu activity. The Izaña samples had the second highest concentrations of dust and plutonium activity, while Barbados had the third highest levels of both crustal aerosols and plutonium activity. The dust concentrations are consistent with previous observations at these remote sites, and we propose that the plutonium (primarily from past atmospheric nuclear weapons testing, much of which took place in arid lands) was deposited on erodible soil surfaces and subsequently transported as part of the overall mineral dust load. The results of this study have implications for the global transport and fate of Pu through its association with dust, the biogeochemical and environmental impacts of other substances associated with dust, and the workings of the dust cycle itself.

  1. Analysis of the Interaction and Transport of Aerosols with Cloud or Fog during Dragon Campaigns from Aeronet and Satellite Remote Sensing

    NASA Astrophysics Data System (ADS)

    Eck, T. F.; Holben, B. N.; Reid, J. S.; Schafer, J.; Giles, D. M.; Kim, J.; Kim, Y. J.; Sano, I.; Lynch, P.; Pickering, K. E.; Crawford, J. H.; Sinyuk, A.; Smirnov, A.; Trevino, N.

    2014-12-01

    Ground-based remote sensing observations from Aerosol Robotic Network (AERONET) sun-sky radiometers have recently shown several instances where cloud-aerosol interaction had resulted in modification of aerosol properties and/or in difficulty identifying some major pollution transport events due to aerosols being imbedded in cloud systems. AERONET has established Distributed Regional Aerosol Gridded Observation Networks (DRAGON) during field campaigns that are short-term (~2-3 months) relatively dense spatial networks of ~15 to 45 sun and sky scanning photometers. Recent major DRAGON field campaigns in Japan and South Korea (Spring 2012) and California (Winter 2013) have yielded observations of aerosol transport associated with clouds and/or aerosol properties modification as a result of fog interaction. Analysis of data from the Korean and Japan DRAGON campaigns shows that major fine-mode aerosol transport events are sometimes associated with extensive cloud cover and that cloud-screening of observations often filter out significant pollution aerosol transport events. The Spectral De-convolution Algorithm (SDA) algorithm was utilized to isolate and analyze the fine-mode aerosol optical depth signal for these cases of persistent and extensive cloud cover. Satellite retrievals of AOD from MODIS sensors were also investigated to assess the issue of detectability of high AOD events associated with high cloud fraction. AERONET is updating the cloud-screening algorithm applied to AOD data in the upcoming Version 3 database. Comparisons of cloud screening from Versions 2 and 3 of cases with high AOD associated with clouds will be studied. Additionally, extensive fog that was coincident with aerosol layer height on some days in both Korea and California resulted in large increases in fine mode aerosol radius, with a mode of cloud-processed or residual aerosol of radius ~0.4-0.5 micron sometimes observed. Cloud processed aerosol may occur much more frequently than AERONET

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

    SciTech Connect

    Yamano, N.; Brockmann, J.E.

    1989-05-01

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

  3. Sulfate Aerosol Formation and Oxidation Pathways on Haze Event over East Asia Region Focusing on Korea.

    NASA Astrophysics Data System (ADS)

    Choi, D.; Koo, Y. S.

    2014-12-01

    The aerosol transports from China largely contribute to high PM (Particulate Matter) concentration in Korea. Especially, secondary inorganic aerosol (SIA) such as nitrate, sulfate and ammonium are largely transported from China to Korea during haze event. The measured PM2.5 (Particle Matter with aerodynamic diameters less than 2.5㎛) concentrations at the supersite monitoring stations in Korea are normally over 100 ug/m3 and SIAs are major chemical species with more than 70% of PM2.5 during the event. According to our air quality forecast model, sulfate concentrations are largely under-predicted in winter and slightly over-predicted in summer. Those discrepancies between model predicted and observed sulfate concentrations are mainly due to uncertainties of precursor emissions of NOx, SO2, and VOCs (Volatile Organic Compounds) and chemical mechanism of the sulfate formation in the chemical forecast model of CMAQ (Community Multiscale Air Quality Model). Formation of sulfate is chemically linked to primary emissions of sulfur dioxide and to be abundancy of atmospheric oxidants such as hydroxyl radical, hydrogen peroxide, ozone, methyl hydroperoxide, and peroxyacetic acid. All of these oxidant species are formed via photochemical reactions with NOx and VOCs. The aim of this work is to investigate the dependency of sulfate formation on oxidant levels in winter and summer during episode event using CMAQ and its sulfate tracking probing tool. The sensitivity of the precursor emissions of SO2, NOx, VOCs and NH3 was also tested to understand the pathways of the sulfate formation. The results show that long range transport from China is a major factor to determine sulfate level in Korea during haze events and dominant mechanisms in the sulfate formation are the gas-phase OH and aqueous phase H2O2 reactions. NOx-SO2-VOCs chemical regimes for the sulfate formation is the VOCs limited regimes in Korea. The further details of the sensitivity run of the precursor emissions and

  4. Modelling of primary aerosols in the chemical transport model MOCAGE: development and evaluation of aerosol physical parameterizations

    NASA Astrophysics Data System (ADS)

    Sič, B.; El Amraoui, L.; Marécal, V.; Josse, B.; Arteta, J.; Guth, J.; Joly, M.; Hamer, P. D.

    2015-02-01

    This paper deals with recent improvements to the global chemical transport model of Météo-France MOCAGE (Modèle de Chimie Atmosphérique à Grande Echelle) that consists of updates to different aerosol parameterizations. MOCAGE only contains primary aerosol species: desert dust, sea salt, black carbon, organic carbon, and also volcanic ash in the case of large volcanic eruptions. We introduced important changes to the aerosol parameterization concerning emissions, wet deposition and sedimentation. For the emissions, size distribution and wind calculations are modified for desert dust aerosols, and a surface sea temperature dependant source function is introduced for sea salt aerosols. Wet deposition is modified toward a more physically realistic representation by introducing re-evaporation of falling rain and snowfall scavenging and by changing the in-cloud scavenging scheme along with calculations of precipitation cloud cover and rain properties. The sedimentation scheme update includes changes regarding the stability and viscosity calculations. Independent data from satellites (MODIS, SEVIRI), the ground (AERONET, EMEP), and a model inter-comparison project (AeroCom) are compared with MOCAGE simulations and show that the introduced changes brought a significant improvement on aerosol representation, properties and global distribution. Emitted quantities of desert dust and sea salt, as well their lifetimes, moved closer towards values of AeroCom estimates and the multi-model average. When comparing the model simulations with MODIS aerosol optical depth (AOD) observations over the oceans, the updated model configuration shows a decrease in the modified normalized mean bias (MNMB; from 0.42 to 0.10) and a better correlation (from 0.06 to 0.32) in terms of the geographical distribution and the temporal variability. The updates corrected a strong positive MNMB in the sea salt representation at high latitudes (from 0.65 to 0.16), and a negative MNMB in the desert

  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. Size distribution and optical properties of mineral dust aerosols transported in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Denjean, C.; Cassola, F.; Mazzino, A.; Triquet, S.; Chevaillier, S.; Grand, N.; Bourrianne, T.; Momboisse, G.; Sellegri, K.; Schwarzenbock, A.; Freney, E.; Mallet, M.; Formenti, P.

    2015-08-01

    This study presents in situ aircraft measurements of Saharan mineral dust transported over the western Mediterranean basin in June-July 2013 during the ChArMEx/ADRIMED (the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) airborne campaign. Dust events differing in terms of source region (Algeria, Tunisia and Morocco), time of tranport (1-5 days) and height of transport were sampled. Mineral dust were transported above the marine boundary layer, which conversely was dominated by pollution and marine aerosols. The dust vertical structure was extremely variable and characterized by either a single layer or a more complex and stratified structure with layers originating from different source regions. Mixing of mineral dust with pollution particles was observed depending on the height of transport of the dust layers. Dust layers carried higher concentration of pollution particles at intermediate altitude (1-3 km) than at elevated altitude (> 3 km), resulting in scattering Angstrom exponent up to 2.2 within the intermediate altitude. However, the optical properties of the dust plumes remained practically unchanged with respect to values previously measured over source regions, regardless of the altitude. Moderate light absorption of the dust plumes was observed with values of aerosol single scattering albedo at 530 nm ranging from 0.90 to 1.00 ± 0.04. Concurrent calculations from the aerosol chemical composition revealed a negligible contribution of pollution particles to the absorption properties of the dust plumes that was due to a low contribution of refractory black carbon in regards to the fraction of dust and sulfate particles. This suggests that, even in the presence of moderate pollution, likely a persistent feature in the Mediterranean, the optical properties of the dust plumes could be assimilated to those of native dust in radiative transfer simulations, modeling studies and

  7. The effects of synoptical weather pattern and complex terrain on the formation of aerosol events in the Greater Taipei area.

    PubMed

    Chuang, Ming-Tung; Chiang, Pen-Chi; Chan, Chang-Chuan; Wang, Chu-Fang; Chang, E-E; Lee, Chung-Te

    2008-07-25

    The aerosol in the Taipei basin is difficult to transport outward under specific weather patterns owing to complex terrain blocking. In this study, seven weather patterns are identified from synoptic weather maps for aerosol events, which occurred from March 2002 to February 2005. Among the identified weather patterns, High Pressure Peripheral Circulation (HPPC), Warm area Ahead of a cold Front (WAF), TYPhoon (TYP), Pacific High Pressure system stretching westerly (PHP), Weak High Pressure system (WHP), and Weak Southern Wind (WSW) are related to terrain blocking. The remaining pattern is High Pressure system Pushing (HPP). The classification of the pollution origin of the air masses shows that 15% of event days were contributed by long-range transport (LRT), 20% by local pollution (LP), and 65% by LRT/LP mix. Terrain blocking causes aerosol accumulation from high atmospheric stability and weak winds occurring under HPPC, TYP, and PHP weather patterns when the Taipei basin is situated on the lee side of the Snow Mountains Chain (SMC). Terrain blocking also occurs when the Taipei basin is situated on the upwind of SMC and Mt. Da-Twen under WAF and WSW patterns. To study the variation of aerosol properties under the mixed influence of terrain and pollution origin, we conducted a field observation simultaneously at the urban, suburban, and background sites in the Greater Taipei area from April 14 to 23, 2004. Terrain blocking plays an important role in aerosol accumulation in the stagnant environment when the Taipei basin is on the lee side of SMC. On the other hand, the PM(2.5) sulfate level is stable with a fraction of 30% in PM(2.5) during the observation period at the urban (25%-33%) and background (25%-41%) sites. It indicates that background PM(2.5) sulfate is high on the West Pacific in winter.

  8. Satellite perspective of aerosol intercontinental transport: From qualitative tracking to quantitative characterization

    NASA Astrophysics Data System (ADS)

    Yu, Hongbin; Remer, Lorraine A.; Kahn, Ralph A.; Chin, Mian; Zhang, Yan

    2013-04-01

    Evidence of aerosol intercontinental transport (ICT) is both widespread and compelling. Model simulations suggest that ICT could significantly affect regional air quality and climate, but the broad inter-model spread of results underscores a need of constraining model simulations with measurements. Satellites have inherent advantages over in situ measurements to characterize aerosol ICT, because of their spatial and temporal coverage. Significant progress in satellite remote sensing of aerosol properties during the Earth Observing System (EOS) era offers the opportunity to increase quantitative characterization and estimates of aerosol ICT beyond the capability of pre-EOS era satellites that could only qualitatively track aerosol plumes. EOS satellites also observe emission strengths and injection heights of some aerosols, aerosol precursors, and aerosol-related gases, which can help characterize aerosol ICT. We review how the current generation of satellite measurements have been used to (1) characterize the evolution of aerosol plumes (e.g., both horizontal and vertical transport, and properties) on an episodic basis, (2) understand the seasonal and inter-annual variations of aerosol ICT and their control factors, (3) estimate the export and import fluxes of aerosols, and (4) evaluate and constrain model simulations. Substantial effort is needed to further explore an integrated approach using measurements from on-orbit satellites (e.g., A-Train synergy) for observational characterization and model constraint of aerosol intercontinental transport and to develop advanced sensors for future missions.

  9. Satellite Perspective of Aerosol Intercontinental Transport: From Qualitative Tracking to Quantitative Characterization

    NASA Technical Reports Server (NTRS)

    Yu, Hongbin; Remer, Lorraine A.; Kahn, Ralph A.; Chin, Mian; Zhang, Yan

    2012-01-01

    Evidence of aerosol intercontinental transport (ICT) is both widespread and compelling. Model simulations suggest that ICT could significantly affect regional air quality and climate, but the broad inter-model spread of results underscores a need of constraining model simulations with measurements. Satellites have inherent advantages over in situ measurements to characterize aerosol ICT, because of their spatial and temporal coverage. Significant progress in satellite remote sensing of aerosol properties during the Earth Observing System (EOS) era offers opportunity to increase quantitative characterization and estimates of aerosol ICT, beyond the capability of pre-EOS era satellites that could only qualitatively track aerosol plumes. EOS satellites also observe emission strengths and injection heights of some aerosols, aerosol precursors, and aerosol-related gases, which can help characterize aerosol ICT. After an overview of these advances, we review how the current generation of satellite measurements have been used to (1) characterize the evolution of aerosol plumes (e.g., both horizontal and vertical transport, and properties) on an episodic basis, (2) understand the seasonal and inter-annual variations of aerosol ICT and their control factors, (3) estimate the export and import fluxes of aerosols, and (4) evaluate and constrain model simulations. Substantial effort is needed to further explore an integrated approach using measurements from on-orbit satellites (e.g., A-Train synergy) for observational characterization and model constraint of aerosol intercontinental transport and to develop advanced sensors for future missions.

  10. Aerosol optical properties at Mauna Loa Observatory - Long-range transport from Kuwait?

    NASA Astrophysics Data System (ADS)

    Bodhaine, B. A.; Harris, J. M.; Ogren, J. A.; Hofmann, D. J.

    1992-03-01

    Aerosol light absorption has been measured continuously at Mauna Loa Observatory, Hawaii (MLO), since April 1990. During the spring of 1991, after oil wells were fired in Kuwait, there was speculation among scientists concerning long-range transport of smoke particles and its possible effect on global climate. The MLO light absorption record from April 1990 to June 1991 shows low values in the 0.1-1 x 10 exp -7 per m range in the summer of 1990, and an increased baseline level of about 2-4 x 10 exp -7 per m with numerous superimposed events in the 5-10 x 10 exp -7 per m range in the spring of 1991. These levels correspond to black carbon (BC) concentrations of 1-10, 20-40, and 50-100 ng/cu m, respectively, under the assumption that BC is the dominant light absorbing species and has a specific absorption of 10 sq m/g. Large-scale 500-hPa trajectories calculated backwards from MLO sometimes show direct transport paths from China and Kuwait to Hawaii that coincide with the black carbon events. These measurements set an upper limit on the possible contribution of Kuwaiti black carbon to the background troposphere near MLO during periods of rapid transport. The aerosol observed at MLO is expected to cause a net cooling of the atmosphere.

  11. Aerosol Sources, Absorption, and Intercontinental Transport: Synergies among Models, Remote Sensing, and Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Ginoux, Paul; Dubovik, Oleg; Holben, Brent; Kaufman, Yoram; chu, Allen; Anderson, Tad; Quinn, Patricia

    2003-01-01

    Aerosol climate forcing is one of the largest uncertainties in assessing the anthropogenic impact on the global climate system. This uncertainty arises from the poorly quantified aerosol sources, especially black carbon emissions, our limited knowledge of aerosol mixing state and optical properties, and the consequences of intercontinental transport of aerosols and their precursors. Here we use a global model GOCART to simulate atmospheric aerosols, including sulfate, black carbon, organic carbon, dust, and sea salt, from anthropogenic, biomass burning, and natural sources. We compare the model calculated aerosol extinction and absorption with those quantities from the ground-based sun photometer measurements from AERONET at several different wavelengths and the field observations from ACE-Asia, and model calculated total aerosol optical depth and fine mode fractions with the MODIS satellite retrieval. We will also estimate the intercontinental transport of pollution and dust aerosols from their source regions to other areas in different seasons.

  12. Aerosol Sources, Absorption, and Intercontinental Transport: Synergies Among Models, Remote Sensing, and Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Chu, Allen; Levy, Robert; Remer, Lorraine; Kaufman, Yoram; Dubovik, Oleg; Holben, Brent; Eck, Tom; Anderson, Tad; Quinn, Patricia

    2004-01-01

    Aerosol climate forcing is one of the largest uncertainties in assessing the anthropogenic impact on the global climate system. This uncertainty arises from the poorly quantified aerosol sources, especially black carbon emissions, our limited knowledge of aerosol mixing state and optical properties, and the consequences of intercontinental transport of aerosols and their precursors. Here we use a global model GOCART to simulate atmospheric aerosols, including sulfate, black carbon, organic carbon, dust, and sea salt, from anthropogenic, .biomass burning, and natural sources. We compare the model calculated aerosol extinction and absorption with those quantities from the ground-based sun photometer measurements from AERON" at several different wavelengths and the field observations from ACE-Asia, and model calculated total aerosol optical depth and fine mode fractions with the MODIS satellite retrieval. We will also estimate the intercontinental transport of pollution and dust aerosols from their source regions to other areas in different seasons.

  13. Observed changes in aerosol physical and optical properties before and after precipitation events

    NASA Astrophysics Data System (ADS)

    Li, Xingmin; Dong, Yan; Dong, Zipeng; Du, Chuanli; Chen, Chuang

    2016-08-01

    Precipitation scavenging of aerosol particles is an important removal process in the atmosphere that can change aerosol physical and optical properties. This paper analyzes the changes in aerosol physical and optical properties before and after four rain events using in situ observations of mass concentration, number concentration, particle size distribution, scattering and absorption coefficients of aerosols in June and July 2013 at the Xianghe comprehensive atmospheric observation station in China. The results show the effect of rain scavenging is related to the rain intensity and duration, the wind speed and direction. During the rain events, the temporal variation of aerosol number concentration was consistent with the variation in mass concentration, but their size-resolved scavenging ratios were different. After the rain events, the increase in aerosol mass concentration began with an increase in particles with diameter <0.8 μm [measured using an aerodynamic particle sizer (APS)], and fine particles with diameter <0.1 μm [measured using a scanning mobility particle sizer (SMPS)]. Rainfall was most efficient at removing particles with diameter ~0.6 μm and greater than 3.5 μm. The changes in peak values of the particle number distribution (measured using the SMPS) before and after the rain events reflect the strong scavenging effect on particles within the 100-120 nm size range. The variation patterns of aerosol scattering and absorption coefficients before and after the rain events were similar, but their scavenging ratios differed, which may have been related to the aerosol particle size distribution and chemical composition.

  14. Fog Induced Aerosol Modification Observed by AERONET, Including Occurrences During Major Air Pollution Events

    NASA Astrophysics Data System (ADS)

    Eck, T. F.; Holben, B. N.; Reid, J. S.; Giles, D. M.; Rivas, M.; Singh, R. P.; Tripathi, S. N.; Bruegge, C. J.; Li, Z.; Platnick, S. E.; Arnold, T.; Ferrare, R. A.; Hostetler, C. A.; Burton, S. P.; Kim, J.; Kim, Y. J.; Sinyuk, A.; Dubovik, O.; Arola, A. T.; Schafer, J.; Artaxo, P.; Smirnov, A.; Chen, H.; Goloub, P.

    2014-12-01

    The modification of aerosol optical properties due to interaction with fog is examined from measurements made by sun/sky radiometers at several AERONET sites. Retrieved total column volume size distributions for cases identified as aerosol modified by fog often show very a large 'middle mode' submicron radius (~0.4 to 0.5 microns), which is typically seen as a component of a bimodal sub-micron distribution. These middle mode sized particles are often called cloud-processed or residual aerosol. This bimodal accumulation mode distribution may be due to one mode (the larger one) from fog-processed aerosol and the other from interstitial aerosol, or possibly from two different aerosol species (differing chemical composition) with differing hygroscopic growth factors. The size of the fine mode particles from AERONET retrieved for these cases exceeds the size of sub-micron sized particles retrieved for nearly all other aerosol types, suggesting significant modification of aerosols within the fog or cloud environment. In-situ measured aerosol size distributions made during other fog events are compared to the AERONET retrievals, and show close agreement in the residual mode particle size. Almucantar retrievals are analyzed from the Kanpur site in the Indo-Gangetic Plain in India (fog in January), Beijing (fog in winter), Fresno, CA in the San Joaquin Valley (fog in winter), South Korea (Yellow Sea fog in spring), Arica on the northern coast of Chile (stratocumulus), and several other sites with aerosol observations made after fog dissipated. Additionally, several major air pollution events are discussed where extremely high aerosol concentrations were measured at the surface and during which fog also occurred, resulting in the detection very large fine mode aerosols (residual mode) from AERONET retrievals in some of these events. Low wind speeds that occurred during these events were conducive to both pollutant accumulation and also fog formation. The presence of fog then

  15. Fog Induced Aerosol Modification Observed by AERONET, Including Occurrences During Major Air Pollution Events

    NASA Astrophysics Data System (ADS)

    Eck, T. F.; Holben, B. N.; Reid, J. S.; Giles, D. M.; Rivas, M.; Singh, R. P.; Tripathi, S. N.; Bruegge, C. J.; Li, Z.; Platnick, S. E.; Arnold, T.; Ferrare, R. A.; Hostetler, C. A.; Burton, S. P.; Kim, J.; Kim, Y. J.; Sinyuk, A.; Dubovik, O.; Arola, A. T.; Schafer, J.; Artaxo, P.; Smirnov, A.; Chen, H.; Goloub, P.

    2015-12-01

    The modification of aerosol optical properties due to interaction with fog is examined from measurements made by sun/sky radiometers at several AERONET sites. Retrieved total column volume size distributions for cases identified as aerosol modified by fog often show very a large 'middle mode' submicron radius (~0.4 to 0.5 microns), which is typically seen as a component of a bimodal sub-micron distribution. These middle mode sized particles are often called cloud-processed or residual aerosol. This bimodal accumulation mode distribution may be due to one mode (the larger one) from fog-processed aerosol and the other from interstitial aerosol, or possibly from two different aerosol species (differing chemical composition) with differing hygroscopic growth factors. The size of the fine mode particles from AERONET retrieved for these cases exceeds the size of sub-micron sized particles retrieved for nearly all other aerosol types, suggesting significant modification of aerosols within the fog or cloud environment. In-situ measured aerosol size distributions made during other fog events are compared to the AERONET retrievals, and show close agreement in the residual mode particle size. Almucantar retrievals are analyzed from the Kanpur site in the Indo-Gangetic Plain in India (fog in January), Beijing (fog in winter), Fresno, CA in the San Joaquin Valley (fog in winter), South Korea (Yellow Sea fog in spring), Arica on the northern coast of Chile (stratocumulus), and several other sites with aerosol observations made after fog dissipated. Additionally, several major air pollution events are discussed where extremely high aerosol concentrations were measured at the surface and during which fog also occurred, resulting in the detection very large fine mode aerosols (residual mode) from AERONET retrievals in some of these events. Low wind speeds that occurred during these events were conducive to both pollutant accumulation and also fog formation. The presence of fog then

  16. Transport of anthropogenic and biomass burning aerosols from Europe to the Arctic during spring 2008

    NASA Astrophysics Data System (ADS)

    Marelle, L.; Raut, J.-C.; Thomas, J. L.; Law, K. S.; Quennehen, B.; Ancellet, G.; Pelon, J.; Schwarzenboeck, A.; Fast, J. D.

    2015-04-01

    During the POLARCAT-France airborne campaign in April 2008, pollution originating from anthropogenic and biomass burning emissions was measured in the European Arctic. We compare these aircraft measurements with simulations using the WRF-Chem model to investigate model representation of aerosols transported from Europe to the Arctic. Modeled PM2.5 is evaluated using European Monitoring and Evaluation Programme (EMEP) measurements in source regions and POLARCAT aircraft measurements in the Scandinavian Arctic. Total PM2.5 agrees well with the measurements, although the model overestimates nitrate and underestimates organic carbon in source regions. Using WRF-Chem in combination with the Lagrangian model FLEXPART-WRF, we find that during the campaign the research aircraft sampled two different types of European plumes: mixed anthropogenic and fire plumes from eastern Europe and Russia transported below 2 km, and anthropogenic plumes from central Europe uplifted by warm conveyor belt circulations to 5-6 km. Both modeled plume types had undergone significant wet scavenging (> 50% PM10) during transport. Modeled aerosol vertical distributions and optical properties below the aircraft are evaluated in the Arctic using airborne lidar measurements. Model results show that the pollution event transported aerosols into the Arctic (> 66.6° N) for a 4-day period. During this 4-day period, biomass burning emissions have the strongest influence on concentrations between 2.5 and 3 km altitudes, while European anthropogenic emissions influence aerosols at both lower (~ 1.5 km) and higher altitudes (~ 4.5 km). As a proportion of PM2.5, modeled black carbon and SO4= concentrations are more enhanced near the surface in anthropogenic plumes. The European plumes sampled during the POLARCAT-France campaign were transported over the region of springtime snow cover in northern Scandinavia, where they had a significant local atmospheric warming effect. We find that, during this transport

  17. Transport of anthropogenic and biomass burning aerosols from Europe to the Arctic during spring 2008

    DOE PAGES

    Marelle, L.; Raut, Jean-Christophe; Thomas, J. L.; Law, K. S.; Quennehen, Boris; Ancellet, G.; Pelon, J.; Schwarzenboeck, A.; Fast, Jerome D.

    2015-04-10

    During the POLARCAT-France airborne campaign in April 2008, pollution originating from anthropogenic and biomass burning emissions was measured in the European Arctic. We compare these aircraft measurements with simulations using the WRF-Chem model to investigate model representation of aerosols transported from Europe to the Arctic. Modeled PM2.5 is evaluated using European Monitoring and Evaluation Programme (EMEP) measurements in source regions and POLARCAT aircraft measurements in the Scandinavian Arctic. Total PM2.5 agrees well with the measurements, although the model overestimates nitrate and underestimates organic carbon in source regions. Using WRF-Chem in combination with the Lagrangian model FLEXPART-WRF, we find that duringmore » the campaign the research aircraft sampled two different types of European plumes: mixed anthropogenic and fire plumes from eastern Europe and Russia transported below 2 km, and anthropogenic plumes from central Europe uplifted by warm conveyor belt circulations to 5–6 km. Both modeled plume types had undergone significant wet scavenging (> 50% PM10) during transport. Modeled aerosol vertical distributions and optical properties below the aircraft are evaluated in the Arctic using airborne lidar measurements. Model results show that the pollution event transported aerosols into the Arctic (> 66.6° N) for a 4-day period. During this 4-day period, biomass burning emissions have the strongest influence on concentrations between 2.5 and 3 km altitudes, while European anthropogenic emissions influence aerosols at both lower (~ 1.5 km) and higher altitudes (~ 4.5 km). As a proportion of PM2.5, modeled black carbon and SO4= concentrations are more enhanced near the surface in anthropogenic plumes. The European plumes sampled during the POLARCAT-France campaign were transported over the region of springtime snow cover in northern Scandinavia, where they had a significant local atmospheric warming effect. We find that, during this

  18. Transport of anthropogenic and biomass burning aerosols from Europe to the Arctic during spring 2008

    SciTech Connect

    Marelle, L.; Raut, Jean-Christophe; Thomas, J. L.; Law, K. S.; Quennehen, Boris; Ancellet, G.; Pelon, J.; Schwarzenboeck, A.; Fast, Jerome D.

    2015-04-10

    During the POLARCAT-France airborne campaign in April 2008, pollution originating from anthropogenic and biomass burning emissions was measured in the European Arctic. We compare these aircraft measurements with simulations using the WRF-Chem model to investigate model representation of aerosols transported from Europe to the Arctic. Modeled PM2.5 is evaluated using European Monitoring and Evaluation Programme (EMEP) measurements in source regions and POLARCAT aircraft measurements in the Scandinavian Arctic. Total PM2.5 agrees well with the measurements, although the model overestimates nitrate and underestimates organic carbon in source regions. Using WRF-Chem in combination with the Lagrangian model FLEXPART-WRF, we find that during the campaign the research aircraft sampled two different types of European plumes: mixed anthropogenic and fire plumes from eastern Europe and Russia transported below 2 km, and anthropogenic plumes from central Europe uplifted by warm conveyor belt circulations to 5–6 km. Both modeled plume types had undergone significant wet scavenging (> 50% PM10) during transport. Modeled aerosol vertical distributions and optical properties below the aircraft are evaluated in the Arctic using airborne lidar measurements. Model results show that the pollution event transported aerosols into the Arctic (> 66.6° N) for a 4-day period. During this 4-day period, biomass burning emissions have the strongest influence on concentrations between 2.5 and 3 km altitudes, while European anthropogenic emissions influence aerosols at both lower (~ 1.5 km) and higher altitudes (~ 4.5 km). As a proportion of PM2.5, modeled black carbon and SO4= concentrations are more enhanced near the surface in anthropogenic plumes. The European plumes sampled during the POLARCAT-France campaign were transported over the region of springtime snow cover in northern Scandinavia, where they had a significant

  19. Characteristics of aerosol pollution during heavy haze events in Suzhou, China

    NASA Astrophysics Data System (ADS)

    Tian, Mi; Wang, Huanbo; Chen, Yang; Yang, Fumo; Zhang, Xiaohua; Zou, Qiang; Zhang, Renquan; Ma, Yongliang; He, Kebin

    2016-06-01

    Extremely severe haze weather events occurred in many cities in China, especially in the east part of the country, in January 2013. Comprehensive measurements including hourly concentrations of PM2.5 and its major chemical components (water-soluble inorganic ions, organic carbon (OC), and elemental carbon (EC)) and related gas-phase precursors were conducted via an online monitoring system in Suzhou, a medium-sized city in Jiangsu province, just east of Shanghai. PM2.5 (particulate matter with an aerodynamic diameter of 2.5 µm or less) frequently exceeded 150 µg m-3 on hazy days, with the maximum reaching 324 µg m-3 on 14 January 2013. Unfavorable weather conditions (high relative humidity (RH), and low rainfall, wind speed, and atmospheric pressure) were conducive to haze formation. High concentrations of secondary aerosol species (including SO42-, NO3-, NH4+, and SOC) and gaseous precursors were observed during the first two haze events, while elevated primary carbonaceous species emissions were found during the third haze period, pointing to different haze formation mechanisms. Organic matter (OM), (NH4)2SO4, and NH4NO3 were found to be the major contributors to visibility impairment. High concentrations of sulfate and nitrate might be explained by homogeneous gas-phase reactions under low RH conditions and by heterogeneous processes under relatively high RH conditions. Analysis of air mass trajectory clustering and potential source contribution function showed that aerosol pollution in the studied areas was mainly caused by local activities and surrounding sources transported from nearby cities.

  20. Intra and inter-continental aerosol transport and local and regional impacts

    NASA Astrophysics Data System (ADS)

    Charles, Leona Ann Marie

    vertical layering of aerosols in the troposphere from passive remote sensing measurements. Therefore, the connection with air pollution is very poor. Furthermore, the vertical structure of the aerosol is very important in assessing transport events and how they mix with the Planetary Boundary Layer (PBL). The need to fill this data gap and supply vertical information on plume detection has led to the launch of the Cloud Aerosol Lidar and Infrared Pathfinder Satellite (CALIPSO) space borne lidar system, which can in principle provide vertical profiles of aerosol backscatter that can be used in the assimilation schemes. One particular problem which needs to be addressed, is the fact that the relationship between the optical scattering coefficients (or AOD) and the PM2.5 mass is not simple. Finally, regarding non-attainment of National Ambient Air Quality Standards (NAAQS), it has also been shown that a significant portion of the PM2.5 aerosol mass can be due to non-local sources. This fact is critical in assessing the appropriate strategy in emission controls, as part of the state implementation plan (SIP) to come into compliance. However, these studies are usually based on statistical analysis tools such as Positive Factor Analysis (PFA), and are not applicable to any single measurement. In addition, little is known about the impact of episodic long range transport as a possible mechanism for affecting local pollution. Such a mechanism cannot be investigated by statistical means or by any existing air transport models which do not consider high altitude plumes (aerosol layers), and must be studied solely with an appropriate suite of measurements including the simultaneous use of sky radiometers, lidars and satellites. Furthermore, since fine particulate matter is so crucial to identify, multi-wavelength determination of aerosol properties such as angstrom coefficient are necessary. It is our purpose to investigate the possibility that such long range transport events can

  1. Study of aerosol behavior on the basis of morphological characteristics during festival events in India

    NASA Astrophysics Data System (ADS)

    Agrawal, Anubha; Upadhyay, Vinay K.; Sachdeva, Kamna

    2011-07-01

    Two important festival events were selected to assess their impacts on atmospheric chemistry by understanding settling velocity and emission time of aerosols. Using high volume sampler, aerosols were collected in a sequential manner to understand settling velocity and emission time of aerosols on a particular day. Composition and total suspended particulate load of the aerosols collected during the festivals were used as markers for strengthening the assessment. Terminal settling velocity of the aerosols were calculated using morphological and elemental compositional data, obtained from scanning electron microcopy (SEM) and energy dispersive X-ray (EDX) study. Aerosol load, black carbon, aromatic carbon and terminal velocity calculations were correlated to obtain conclusion that aerosols collected on the festival day might have been emitted prior to the festival. Settling time of aerosols collected on 17th and 19th October'09 during Diwali were found to be 36.5 (1.5 days) and 12.8 h, respectively. Carbon concentration estimated using EDX was found to be almost double in the sample collected after 2 days of the festival event. This strengthens our inference of time calculation where carbon with high concentration of load must have settled approximately after two days of the event. Settling time of aerosols collected on Holi morning and afternoon was found to be 1.7 and 24.8 h, respectively. Further, because of the small distance of 5.4 km between the meteorological station and sampling site, observed TSP values were compared with theoretical load values, calculated by using visibility values taken from the meteorological data. And it was found that both experimental and calculated values are close to each other about 50% of the times, which proves the assumption that experimental and meteorological data are comparable.

  2. Inland transport of marine aerosols in southern Sweden

    NASA Astrophysics Data System (ADS)

    Gustafsson, Mats E. R.; Franzén, Lars G.

    The transport of marine aerosols across southern Sweden was studied using six meteorological stations in a transect from west- to east-coast. Measurements were made during dry westerlies on 10 occasions during 1995. The concentration and flux of salt in the air was measured using "salt vanes". It is concluded that marine salt is transported along the whole transect at all occasions and that the concentration and flux of salt decrease with downwind distance from the coast as an inversed power function. The two easternmost stations show a slight increase towards the east-coast. Variability of the data is high on the west coast due to strong influence from the coastal production of aerosols. This effect diminishes along downwind forming lower, less variable concentration further inland. Statistical models based on the data are in relatively good agreement with previous models and data. Further, salt content on Scots Pine ( Pinus sylvestris, L) needles after two westerly gale occasions, in profiles from west- to east-coast, were analysed. The Cl -/Na +, Ca 2+/Na +, K +/Na +, Mg 2+/Na + and SO 42-/Na + ratios were studied revealing a clear downwind decrease in Ca 2+/Na + and Mg 2+/Na +, a close to sea water ratio for Cl -/Na + and an excess of SO 42- along the profile. Also, the importance of degree of exposure was studied concluding that the roughness of the upwind surface is an important factor for the deposition onto trees in forest edges.

  3. Spatial distribution of carbonaceous aerosol in the southeastern Baltic Sea region (event of grass fires)

    NASA Astrophysics Data System (ADS)

    Dudoitis, Vadimas; Byčenkienė, Steigvilė; Plauškaitė, Kristina; Bozzetti, Carlo; Fröhlich, Roman; Mordas, Genrik; Ulevičius, Vidmantas

    2016-05-01

    The aerosol chemical composition in air masses affected by large vegetation fires transported from the Kaliningrad region (Russia) and southeast regions (Belarus and Ukraine) during early spring (March 2014) was characterized at the remote background site of Preila, Lithuania. In this study, the chemical composition of the particulate matter was studied by high temporal resolution instruments, including an Aerosol Chemical Speciation Monitor (ACSM) and a seven-wavelength aethalometer. Air masses were transported from twenty to several hundred kilometres, arriving at the measurement station after approximately half a day of transport. The concentration-weighted trajectory analysis suggests that organic aerosol particles are mainly transported over the Baltic Sea and the continent (southeast of Belarus). Results show that a significant fraction of the vegetation burning organic aerosol is transformed into oxidised forms in less than a half-day. Biomass burning aerosol (BBOA) was quantified from the ACSM data using a positive matrix factorization (PMF) analysis, while its spatial distribution was evaluated using air mass clustering approach.

  4. Aerosol chemical composition in cloud events by high resolution time-of-flight aerosol mass spectrometry.

    PubMed

    Hao, Liqing; Romakkaniemi, Sami; Kortelainen, Aki; Jaatinen, Antti; Portin, Harri; Miettinen, Pasi; Komppula, Mika; Leskinen, Ari; Virtanen, Annele; Smith, James N; Sueper, Donna; Worsnop, Douglas R; Lehtinen, Kari E J; Laaksonen, Ari

    2013-03-19

    This study presents results of direct observations of aerosol chemical composition in clouds. A high-resolution time-of-flight aerosol mass spectrometer was used to make measurements of cloud interstitial particles (INT) and mixed cloud interstitial and droplet residual particles (TOT). The differences between these two are the cloud droplet residuals (RES). Positive matrix factorization analysis of high-resolution mass spectral data sets and theoretical calculations were performed to yield distributions of chemical composition of the INT and RES particles. We observed that less oxidized hydrocarbon-like organic aerosols (HOA) were mainly distributed into the INT particles, whereas more oxidized low-volatile oxygenated OA (LVOOA) mainly in the RES particles. Nitrates existed as organic nitrate and in chemical form of NH(4)NO(3). Organic nitrates accounted for 45% of total nitrates in the INT particles, in clear contrast to 26% in the RES particles. Meanwhile, sulfates coexist in forms of acidic NH(4)HSO(4) and neutralized (NH(4))(2)SO(4). Acidic sulfate made up 64.8% of total sulfates in the INT particles, much higher than 10.7% in the RES particles. The results indicate a possible joint effect of activation ability of aerosol particles, cloud processing, and particle size effects on cloud formation.

  5. Validation of the assimilation of satellite-based aerosol measurements into a chemical transport model using aerosol component information

    NASA Astrophysics Data System (ADS)

    Martynenko, Dmytro; Holzer-Popp, Thomas; Schroedter-Homscheidt, Marion

    Aerosol monitoring is of growing interest due to the impact of aerosol particle concentration on human health and the global climate. The key question of this paper is to understand how the assimilation of satellite atmospheric aerosol observations with enhanced observation and background covariance matrices improves the capability of a chemical transport model in reproducing the distribution of tropospheric particles. The task of this study is a validation of assimilation results by using ground-based AERONET measurements for 2006-2008 at stations from Europe and Africa regions. The study is carried out using the Model for Atmospheric Transport and Chemistry (MATCH operated at DLR). As measurement input vector for as-similation satellite data from SCIAMACHY and AATSR instruments onboard ENVISAT was used. Synergetic Aerosol Retrieval (SYNAER) observational and model data have been cou-pled by means of data the two-dimensional variational assimilation. SYNAER measurements are able to distinguish between different aerosol components such as water-soluble, soot, sea salt and long-range transported mineral aerosols. The final analysis is highly dependent on the specification of the error covariance matrices. Since observation and background error covari-ance matrices are not perfectly known, a large potential for improvements of the analyses is offered by methods allowing their constructing and tuning. In this study, a method proposed by Desroziers and Ivanov (2001) is used to tune background and observational error statistics of the 2D-Var assimilation procedure by using information content analysis of the retrieval algorithm.

  6. Inland Transport of Aerosolized Florida Red Tide Toxins.

    PubMed

    Kirkpatrick, Barbara; Pierce, Richard; Cheng, Yung Sung; Henry, Michael S; Blum, Patricia; Osborn, Shannon; Nierenberg, Kate; Pederson, Bradley A; Fleming, Lora E; Reich, Andrew; Naar, Jerome; Kirkpatrick, Gary; Backer, Lorraine C; Baden, Daniel

    2010-02-01

    Florida red tides, an annual event off the west coast of Florida, are caused by the toxic dinoflagellate, Karenia brevis. K. brevis produces a suite of potent neurotoxins, brevetoxins, which kill fish, sea birds, and marine mammals, as well as sickening humans who consume contaminated shellfish. These toxins become part of the marine aerosol, and can also be inhaled by humans and other animals. Recent studies have demonstrated a significant increase in symptoms and decrease lung function in asthmatics after only one hour of beach exposure during an onshore Florida red tide bloom.This study constructed a transect line placing high volume air samplers to measure brevetoxins at sites beginning at the beach, moving approximately 6.4 km inland. One non-exposure and 2 exposure studies, each of 5 days duration, were conducted. No toxins were measured in the air during the non-exposure period. During the 2 exposure periods, the amount of brevetoxins varied considerably by site and by date. Nevertheless, brevetoxins were measured at least 4.2 kilometers from the beach and/or 1.6 km from the coastal shoreline. Therefore, populations sensitive to brevetoxins (such as asthmatics) need to know that leaving the beach may not discontinue their environmental exposure to brevetoxin aerosols.

  7. Aerosol transport of biomass burning to the Bolivian Andean region from remote sensing measurements

    NASA Astrophysics Data System (ADS)

    Perez-Ramirez, Daniel; Whiteman, David; Andrade, Marcos; Gasso, Santiago; Stein, Ariel; Torres, Omar; Eck, Tom; Velarde, Fernando; Aliaga, Diego

    2016-04-01

    This work deals with the analysis of columnar aerosol optical and microphysical properties obtained by the AERONET network in the region of Bolivia and its border with Brazil. Through the long record AERONET measurements we focus in the transport of biomass-burning aerosol from the Amazon basin (stations at Rio Branco, Cuiba, Ji Parana and Santa Cruz) to the Andean Altiplano (altitude above 3000 m a.s.l. at the station in the city of La Paz). Also, measurements from the space-sensors MODIS and OMI are used to understand spatial distribution. The main results is the high impact in the aerosol load during the months of August, September and August with mean values of aerosol optical depth at 500 nm (AOD) at the low lands of ≈ 0.60 ± 0.60 and Angstrom exponent (α(440-870)) of ≈ 1.52 ± 0.38. Satellite measurements also follow very similar patterns. Also, that season is characterized by some extreme events that can reach AOD of up to 6.0. Those events are cloud-screened by MODIS but not by OMI sensor, which is attributed to different pixel resolutions. The biomass-burning is clearly transport to the Andean region where higher values of AOD (~ 0.12 ± 0.06 versus 0.09 ± 0.04 in the no biomass-burning season) and α(440-870) (~ 0.95 ± 0.30 versus 0.84 ± 0.3 in the no biomass-burning season). However, the intensity of the biomass-burning season varies between different years. Analysis of precipitation anomalies using TRNM satellites indicates a strong correlation with AOD, which suggest that on dry years there is less vegetation to burn and so less aerosol load. The opposite is found for positive anomalies of precipitation. In the transport of biomass burning larger values of the effective radius (reff) are observed in La Paz (reff = 0.26 ± 0.10 μm) than in the low lands (reff = 0.63 ± 0.24 μm), which has been explained by aerosol aging processes. Moreover, although the spectral dependence is similar, single scattering albedo (SSA) is larger in the low lands

  8. Aerosol transport and deposition efficiency in the respiratory airways

    NASA Astrophysics Data System (ADS)

    Nicolaou, Laura; Zaki, Tamer

    2015-11-01

    Prediction of aerosol deposition in the respiratory system is important for improving the efficiency of inhaled drug delivery and for assessing the toxicity of airborne pollutants. Particle deposition in the airways is typically described as a function of the Stokes number based on a reference flow timescale. This choice leads to significant scatter in deposition data since the velocity and length scales experienced by the particles as they are advected through the flow deviate considerably from the reference values in many sections of the airways. Therefore, the use of an instantaneous Stokes number based on the local properties of the flow field is proposed instead. We define the effective Stokes number as the time-average of the instantaneous value. Our results demonstrate that this average, or effective, Stokes number can deviate significantly from the reference value particularly in the intermediate Stokes number range. In addition, the effective Stokes number shows a very clear correlation with deposition efficiency, and is therefore a more appropriate parameter to describe aerosol transport.

  9. Assessing Impact of Aerosol Intercontinental Transport on Regional Air Quality and Climate: What Satellites Can Help

    NASA Technical Reports Server (NTRS)

    Yu, Hongbin

    2011-01-01

    Mounting evidence for intercontinental transport of aerosols suggests that aerosols from a region could significantly affect climate and air quality in downwind regions and continents. Current assessment of these impacts for the most part has been based on global model simulations that show large variability. The aerosol intercontinental transport and its influence on air quality and climate involve many processes at local, regional, and intercontinental scales. There is a pressing need to establish modeling systems that bridge the wide range of scales. The modeling systems need to be evaluated and constrained by observations, including satellite measurements. Columnar loadings of dust and combustion aerosols can be derived from the MODIS and MISR measurements of total aerosol optical depth and particle size and shape information. Characteristic transport heights of dust and combustion aerosols can be determined from the CALIPSO lidar and AIRS measurements. CALIPSO liar and OMI UV technique also have a unique capability of detecting aerosols above clouds, which could offer some insights into aerosol lofting processes and the importance of above-cloud transport pathway. In this presentation, I will discuss our efforts of integrating these satellite measurements and models to assess the significance of intercontinental transport of dust and combustion aerosols on regional air quality and climate.

  10. Long Range Transport of Aerosols and Trace Gases from China: The Role of Dry Convection.

    NASA Astrophysics Data System (ADS)

    Dickerson, R. R.; Levy, R.; Li, C.; Li, Z.; Lackson, M. T.; Jeffrey, S.

    2006-05-01

    Substantial concentrations of trace gases and aerosols are lofted and carried from Asia over the Pacific producing an inter-hemispheric impact on atmospheric chemistry and climate. The meteorological mechanism leading to this large-scale transport of dust and pollutants remains a major uncertainty in quantifying the global effects of emissions from the developing world. Models and downwind measurements have identified isentropic advection associated with wave cyclones (warm conveyor belt, WCB,circulation) as an important mechanism. We present data from a case study conducted s part of EAST-AIRE in April 2005 in which upstream convection, rather that WCB lofting appears to dominate. Observations from instrumented aircraft flights (O3, CO, SO2, and aerosol optical properties), back trajectories, and satellite images of clouds (GOES) and aerosols (MODIS) are analyzed. These show that dry (non-precipitating) convection ahead of cold fronts can be an important mechanism for converting local air pollution problems into regional or global atmospheric chemistry problems. Climatological spring (MAM) precipitation over NE China is low, about 90 mm compared to 290 mm over the NE US. Cloud cover, however, is similar with cumulus clouds reported about 7% of the time over NE China and about 9% of the time over the NE US suggesting that this is not an isolated event. Evaluation of models' convective schemes and further observations near the source regions are called for.

  11. Contribution of long-range transported aerosols to aerosol optical and physical properties: 3-year measurements at Gosan, Korea

    NASA Astrophysics Data System (ADS)

    Heo, J.; Kim, S. W.; Kim, J. H.; Ogren, J. A.; Yoon, S. C.

    2015-12-01

    Recently, more attentions have been paid to air quality in East Asia due to the enhanced loading of atmospheric pollutants related to rapid industrialization. Gosan Climate Observatory (GCO), Korea is regarded as an ideal site to study the transport of atmospheric pollutants because it is frequently influenced by various airmasses from China, Korea, Japan and Pacific Ocean. In order to understand aerosol optical and physical properties according to airmass transport routes, three-year (2012-2014) continuous measurements of aerosol scattering/absorption coefficient and number size distribution were analyzed, together with 48-hour backward trajectory calculations. The averaged aerosol absorption (σa) and scattering coefficient (σs) for airmasses transported from North China (NC; 36% of all trajectories) were 6.65 Mm-1 and 94.72 Mm-1 at 550 nm wavelength, respectively, which were similar to those for stagnant airmasses (ST; 22% of all trajectories; σa: 6.26 Mm-1, σs: 93.99 Mm-1). The highest values of σa (7.03 Mm-1) and σs (108.34 Mm-1) were observed when airmasses were traveled from South China (SC; 11% of all trajectories). σa and σs for airmasses from Korean Peninsula (KP; 7% of all trajectories) and Pacific Ocean (PO; 14% of all trajectories; in parenthesis) were 5.63 (2.76) Mm-1 and 73.63 (50.93) Mm-1, respectively. Compared to other airmasses, the higher values of Scattering Angstrom Exponent (SAE) for ST (1.65) is thought to be the build-up of anthropogenic fine particulate pollutants. The Absorption Angstrom Exponent (AAE) was estimated to be 1.32 for NC airmass and 1.02 for SC airmass. Over the study period, 130 days of total 557 days were identified as new particle formation and growth event (NPF) from Scanning Mobility Particle Sizer (SMPS) measurements by Cyclostationary Empirical Orthogonal Function (CSEOF) approach. Especially, 55.4% (72 days) of total 130 NPF days were found when a cold and dry airmass comes from NC after passing the frontal

  12. Transport, vertical structure and radiative properties of dust events in southeast China determined from ground and space sensors

    NASA Astrophysics Data System (ADS)

    Liu, Jianjun; Zheng, Youfei; Li, Zhanqing; Flynn, Connor; Welton, E. J.; Cribb, Mareen

    2011-11-01

    Two dust events were detected over the Yangtze Delta region of China during March 14-17 and April 25-26 in 2009 where such dust events are uncommon. The transport behavior, spatio-temporal evolution, vertical structure, direct radiative effects, as well as induced heating rates, are investigated using a combination of ground-based and satellite-based measurements, a back-trajectory analysis, an aerosol model and a radiative transfer model. Back-trajectories, wind fields and aerosol model analyses show that the first dust originated in northern/northwestern China and the second generated in the Taklimakan desert in northwest China, and traveled across the Hexi corridor and Loess Plateau to the Yangtze Delta region (the so-called "dust corridor"). The mean lidar extinction-to-backscatter ratio (LR) during the two dust events was 38.7 ± 10.4 sr and 42.7 ± 15.2 sr, respectively. The mean aerosol depolarization ratio ( δa) for the first dust event was 0.16 ± 0.07, with a maximum value of 0.32. For the second, the mean δa was around 0.19 ± 0.06, with a maximum value of 0.29. Aerosol extinction coefficient and δa profiles for the two events were similar: two aerosol layers consisting of dust aerosols and a mixture of dust and anthropogenic pollution aerosols. The topmost aerosol layer is above 3.5 km. The maximum mean aerosol extinction coefficients were 0.5 km -1 and 0.54 km -1 at about 0.7 km and 1.1 km, respectively. Significant effects of cooling at the surface and heating in the atmosphere were found during these dust events. Diurnal mean shortwave radiative forcings (efficiencies) at the surface, the top-of-the-atmosphere and within the atmosphere were -36.8 (-80.0), -13.6 (-29.6) and 23.2 (50.4) W m -2, respectively, during the first dust event, and -48.2 (-70.9), -21.4 (-31.5) and 26.8 (39.4) W m -2, respectively, during the second dust event. Maximum heating rates occurred at 0.7 km during the first dust event and at 1.1 km during the second dust event

  13. Columnar aerosol optical properties at AERONET sites in central eastern Asia and aerosol transport to the tropical mid-Pacific

    NASA Astrophysics Data System (ADS)

    Eck, T. F.; Holben, B. N.; Dubovik, O.; Smirnov, A.; Goloub, P.; Chen, H. B.; Chatenet, B.; Gomes, L.; Zhang, X.-Y.; Tsay, S.-C.; Ji, Q.; Giles, D.; Slutsker, I.

    2005-03-01

    The column-integrated optical properties of aerosol in the central eastern region of Asia and midtropical Pacific were investigated based on Sun/sky radiometer measurements made at Aerosol Robotic Network (AERONET) sites in these regions. Characterization of aerosol properties in the Asian region is important due to the rapid growth of both population and economic activity, with associated increases in fossil fuel combustion, and the possible regional and global climatic impacts of related aerosol emissions. Multiyear monitoring over the complete annual cycle at sites in China, Mongolia, South Korea, and Japan suggest spring and/or summer maximum in aerosol optical depth (τa) and a winter minimum; however, more monitoring is needed to establish accurate climatologies. The annual cycle of Angstrom wavelength exponent (α) showed a springtime minimum associated with dust storm activity; however, the monthly mean α440-870 was >0.8 even for the peak dust season at eastern Asian sites suggesting that fine mode pollution aerosol emitted from population centers in eastern Asia dominates the monthly aerosol optical influence even in spring as pollution aerosol mixes with coarse mode dust originating in western source regions. Aerosol optical depth peaks in spring in the tropical mid-Pacific Ocean associated with seasonal shifts in atmospheric transport from Asia, and ˜35% of the springtime τa500 enhancement occurs at altitudes above 3.4 km. For predominately fine mode aerosol pollution cases, the average midvisible (˜550 nm) single scattering albedo (ω0) at two continental urban sites in China averaged ˜0.89, while it was significantly higher, ˜0.93, at two relatively rural coastal sites in South Korea and Japan. Differences in fine mode absorption between these regions may result from a combination of factors including aerosol aging during transport, relative humidity differences, sea salt at coastal sites, and fuel type and combustion differences in the two

  14. Effects of agriculture crop residue burning on aerosol properties and long-range transport over northern India: A study using satellite data and model simulations

    NASA Astrophysics Data System (ADS)

    Vijayakumar, K.; Safai, P. D.; Devara, P. C. S.; Rao, S. Vijaya Bhaskara; Jayasankar, C. K.

    2016-09-01

    Agriculture crop residue burning in the tropics is a major source of the global atmospheric aerosols and monitoring their long-range transport is an important element in climate change studies. In this paper, we study the effects of agriculture crop residue burning on aerosol properties and long-range transport over northern India during a smoke event that occurred between 09 and 17 November 2013, with the help of satellite measurements and model simulation data. Satellite data observations on aerosol properties suggested transport of particles from agriculture crop residue burning in Indo-Gangetic Plains (IGP) over large regions. Additionally, ECMWF winds at 850 hPa have been used to trace the source, path and spatial extent of smoke events. Most of the smoke aerosols, during the study period, travel from a west-to-east pathway from the source-to-sink region. Furthermore, aerosol vertical profiles from CALIPSO show a layer of thick smoke extending from surface to an altitude of about 3 km. Smoke aerosols emitted from biomass burning activity from Punjab have been found to be a major contributor to the deterioration of local air quality over the NE Indian region due to their long range transport.

  15. Evolution of Asian aerosols during transpacific transport in INTEX-B

    SciTech Connect

    Dunlea, E. J.; DeCarlo, Peter; Aiken, Allison; Kimmel, Joel; Peltier, R. E.; Weber, R. J.; Tomlinson, Jason M.; Collins, Donald R.; Shinozuka, Yohei; McNaughton, C. S.; Howell, S. G.; Clarke, A. D.; Emmons, L.; Apel, Eric; Pfister, G. G.; van Donkelaar, A.; Martin, R. V.; Millet, D. B.; Heald, C. L.; Jimenez, J. L.

    2009-10-01

    Measurements of aerosol composition were made with an Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) on board the NSF/NCAR C-130 aircraft as part of the Intercontinental Chemical Transport Experiment Phase B 5 (INTEX-B) field campaign over the Eastern Pacific Ocean. The HR-ToF-AMS measurements of non-refractory submicron aerosol mass are shown to compare well with other aerosol instrumentation in the INTEX-B field study. Two case studies are described for pollution layers transported across the Pacific from the Asian continent, intercepted 3–4 days and 7–10 days downwind of Asia, respectively. Aerosol chemistry is shown to 10 be a robust tracer for air masses originating in Asia, specifically the presence of sulfate dominated aerosol is a distinguishing feature of Asian pollution layers that have been transported to the Eastern Pacific. We examine the time scales of processing for sulfate and organic aerosol in the atmosphere and show that our observations confirm a conceptual model for transpacific transport from Asia proposed by Brock et al. (2004). 15 Our observations of both sulfate and organic aerosol in aged Asian pollution layers are consistent with fast formation near the Asian continent, followed by washout during lofting and subsequent transformation during transport across the Pacific. Our observations are the first atmospheric measurements to indicate that although secondary organic aerosol (SOA) formation from pollution happens on the timescale of one day, 20 the oxidation of organic aerosol continues at longer timescales in the atmosphere. Comparisons with chemical transport models of data from the entire campaign reveal an under-prediction of SOA mass in the MOZART model, but much smaller discrepancies with the GEOS-Chem model than found in previous studies over the Western Pacific. No evidence is found to support a previous hypothesis for significant secondary 25 organic aerosol formation in the free troposphere.

  16. Evaluating aerosol impacts on Numerical Weather Prediction in two extreme dust and biomass-burning events

    NASA Astrophysics Data System (ADS)

    Remy, Samuel; Benedetti, Angela; Jones, Luke; Razinger, Miha; Haiden, Thomas

    2014-05-01

    The WMO-sponsored Working Group on Numerical Experimentation (WGNE) set up a project aimed at understanding the importance of aerosols for numerical weather prediction (NWP). Three cases are being investigated by several NWP centres with aerosol capabilities: a severe dust case that affected Southern Europe in April 2012, a biomass burning case in South America in September 2012, and an extreme pollution event in Beijing (China) which took place in January 2013. At ECMWF these cases are being studied using the MACC-II system with radiatively interactive aerosols. Some preliminary results related to the dust and the fire event will be presented here. A preliminary verification of the impact of the aerosol-radiation direct interaction on surface meteorological parameters such as 2m Temperature and surface winds over the region of interest will be presented. Aerosol optical depth (AOD) verification using AERONET data will also be discussed. For the biomass burning case, the impact of using injection heights estimated by a Plume Rise Model (PRM) for the biomass burning emissions will be presented.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  18. Climatology of the aerosol optical depth by components from the Multi-angle Imaging SpectroRadiometer (MISR) and chemistry transport models

    NASA Astrophysics Data System (ADS)

    Lee, Huikyo; Kalashnikova, Olga V.; Suzuki, Kentaroh; Braverman, Amy; Garay, Michael J.; Kahn, Ralph A.

    2016-06-01

    The Multi-angle Imaging SpectroRadiometer (MISR) Joint Aerosol (JOINT_AS) Level 3 product has provided a global, descriptive summary of MISR Level 2 aerosol optical depth (AOD) and aerosol type information for each month over 16+ years since March 2000. Using Version 1 of JOINT_AS, which is based on the operational (Version 22) MISR Level 2 aerosol product, this study analyzes, for the first time, characteristics of observed and simulated distributions of AOD for three broad classes of aerosols: spherical nonabsorbing, spherical absorbing, and nonspherical - near or downwind of their major source regions. The statistical moments (means, standard deviations, and skewnesses) and distributions of AOD by components derived from the JOINT_AS are compared with results from two chemistry transport models (CTMs), the Goddard Chemistry Aerosol Radiation and Transport (GOCART) and SPectral RadIatioN-TrAnSport (SPRINTARS). Overall, the AOD distributions retrieved from MISR and modeled by GOCART and SPRINTARS agree with each other in a qualitative sense. Marginal distributions of AOD for each aerosol type in both MISR and models show considerable high positive skewness, which indicates the importance of including extreme AOD events when comparing satellite retrievals with models. The MISR JOINT_AS product will greatly facilitate comparisons between satellite observations and model simulations of aerosols by type.

  19. Effects of Spatial Resolution on the Simulated Dust Aerosol Lifecycle: Implications for Dust Event Magnitude and Timing in the NASA GEOS-5 AGCM

    NASA Technical Reports Server (NTRS)

    Nowottnick, E.; Colarco, Peter R.; daSilva, A.

    2011-01-01

    The NASA GEOS-5 atmospheric transport model simulates global aerosol distributions with an online aerosol module. GEOS-5 may be run at various horizontal spatial resolutions depending on the research application. For example, long integration climate simulations are typically run at 2 deg or 1 deg grid spacing, whereas aerosol reanalysis and forecasting applications may be performed at O.5 deg or 0.25 deg resolutions. In this study, we assess the implications of varying spatial resolution on the simulated aerosol fields, with a particular focus on dust. Dust emissions in GEOS-5 are calculated with one of two parameterizations, one based on the Goddard Chemistry, Aerosol, Radiation, and Transport (GO CART) model and another based on the Dust Entrainment and Deposition (DEAD) model. Emission fluxes are parameterized in terms of the surface wind speed, either the 10-m (GO CART) or friction (DEAD) wind speed. We consider how surface wind speeds and thus the dust emission rates are a function of the model spatial resolution. We find that spatial resolution has a significant effect on the magnitude of dust emissions, as higher resolution versions of the model have typically higher surface wind speeds. Utilizing space-borne observations from MISR, MODIS, and CALIOP, we find that simulated Aerosol Optical Thickness (AOT) distributions respond differently to spatial resolution over the African and Asian source regions, highlighting the need to regional dust emission tuning. When compared to ground-based observations from AERONET, we found improved timing of dust events with as spatial resolution was increased. In an attempt to improve the representation of the dust aerosol lifecycle at coarse resolutions, we found that incorporating the effects of sub-grid wind variability in a course resolution simulation led to improved agreement with observed AOT magnitudes, but did not impact the timing of simulated dust events.

  20. Monitoring and tracking the trans-Pacific transport of aerosols using multi-satellite aerosol optical depth retrievals

    NASA Astrophysics Data System (ADS)

    Naeger, A. R.; Gupta, P.; Zavodsky, B.; McGrath, K. M.

    2015-10-01

    The primary goal of this study was to generate a near-real time (NRT) aerosol optical depth (AOD) product capable of providing a comprehensive understanding of the aerosol spatial distribution over the Pacific Ocean in order to better monitor and track the trans-Pacific transport of aerosols. Therefore, we developed a NRT product that takes advantage of observations from both low-earth orbiting and geostationary satellites. In particular, we utilize AOD products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) satellites. Then, we combine these AOD products with our own retrieval algorithms developed for the NOAA Geostationary Operational Environmental Satellite (GOES-15) and Japan Meteorological Agency (JMA) Multi-functional Transport Satellite (MTSAT-2) to generate a NRT daily AOD composite product. We present examples of the daily AOD composite product for a case study of trans-Pacific transport of Asian pollution and dust aerosols in mid-March 2014. Overall, the new product successfully tracks this aerosol plume during its trans-Pacific transport to the west coast of North America. However, we identify several areas across the domain of interest from Asia to North America where the new product can encounter significant uncertainties due to the inclusion of the geostationary AOD retrievals. The uncertainties associated with geostationary AOD retrievals are expected to be minimized after the successful launch of the next-generation advanced NOAA GOES-R and recently launched JMA Himawari satellites. Observations from these advanced satellites will ultimately provide an enhanced understanding of the spatial and temporal distribution of aerosols over the Pacific.

  1. Contributions of local sources, long-range and mountain wind transport for aerosols over an eastern Himalayan high-altitude station in India

    NASA Astrophysics Data System (ADS)

    Chatterjee, Abhijit; Sarkar, Chirantan; Singh, Ajay; Ghosh, Sanjay; Raha, Sibaji; Das, Sanat

    A long-term study (2010-2013) on aerosols mass concentrations (PM2.5), number concentrations of size segregated aerosols and mass concentration of total suspended black carbon aerosols has been made over Darjeeling (27.01 N, 88.15 E), a high altitude (2200 m asl) station at eastern Himalaya in India. Seasonal and diurnal variation of all types of aerosols, their chemical composition and source apportionment revealed that aerosols over this part of Himalaya are mainly of two types; locally generated and long-range transported aerosols. The diurnal variation of aerosols including black carbon showed distinct feature of up-slope mountain wind transport mainly during premonsoon (Mar-May) which brings aerosol particles from low land regions. This present study focuses on the estimation of the individual contributions from local emissions (LE), long-range transport (LRT) and mountain wind transport (MWT) towards the total aerosol loading over Darjeeling. Several strike events (called by local political party) were observed at Darjeeling over the entire period of study (2008-2013) when all the local activities (schools, colleges, offices, vehicular, industrial etc) were stopped fully. Most of the strike events occurred during premonsoon. We have observed three types of events during premonsoon over the entire study period; 1) strike events with the contribution of LRT+MWT with zero local emissions (LE=0), 2) normal days with the contribution of LE+LRT+MWT, 3) normal days with the contribution of LE+MWT with zero long-range contribution (LRT=0). On normal days, the diurnal variation of aerosols during premonsoon showed sharp morning and evening peaks associated to local anthropogenic activities with the effect of up-slope mountain wind during afternoon. During strike events, the morning and evening peaks were absent but a broad peak was observed during afternoon associated to up-slope mountain wind. The increase in aerosol concentrations during afternoon on strike days

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

    NASA Astrophysics Data System (ADS)

    Fast, Jerome D.; Berg, Larry K.; Zhang, Kai; Easter, Richard C.; Ferrare, Richard A.; Hair, Johnathan W.; Hostetler, Chris A.; Liu, Ying; Ortega, Ivan; Sedlacek, Arthur; Shilling, John E.; Shrivastava, Manish; Springston, Stephen R.; Tomlinson, Jason M.; Volkamer, Rainer; Wilson, Jacqueline; Zaveri, Rahul A.; Zelenyuk, Alla

    2016-08-01

    The ability of the Weather Research and Forecasting model with chemistry (WRF-Chem) version 3.7 and the Community Atmosphere Model version 5.3 (CAM5) in simulating profiles of aerosol properties is quantified using extensive in situ and remote sensing measurements from the Two-Column Aerosol Project (TCAP) conducted during July of 2012. TCAP was supported by the U.S. Department of Energy's Atmospheric Radiation Measurement program and was designed to obtain observations within two atmospheric columns; one fixed over Cape Cod, Massachusetts, and the other several hundred kilometers over the ocean. The performance is quantified using most of the available aircraft and surface measurements during July, and 2 days are examined in more detail to identify the processes responsible for the observed aerosol layers. The higher-resolution WRF-Chem model produced more aerosol mass in the free troposphere than the coarser-resolution CAM5 model so that the fraction of aerosol optical thickness above the residual layer from WRF-Chem was more consistent with lidar measurements. We found that the free troposphere layers are likely due to mean vertical motions associated with synoptic-scale convergence that lifts aerosols from the boundary layer. The vertical displacement and the time period associated with upward transport in the troposphere depend on the strength of the synoptic system and whether relatively high boundary layer aerosol concentrations are present where convergence occurs. While a parameterization of subgrid scale convective clouds applied in WRF-Chem modulated the concentrations of aerosols aloft, it did not significantly change the overall altitude and depth of the layers.

  3. An observation-based approach to identify local natural dust events from routine aerosol ground monitoring

    NASA Astrophysics Data System (ADS)

    Tong, D. Q.; Dan, M.; Wang, T.; Lee, P.

    2012-02-01

    Dust is a major component of atmospheric aerosols in many parts of the world. Although there exist many routine aerosol monitoring networks, it is often difficult to obtain dust records from these networks, because these monitors are either deployed far away from dust active regions (most likely collocated with dense population) or contaminated by anthropogenic sources and other natural sources, such as wildfires and vegetation detritus. Here we propose a new approach to identify local dust events relying solely on aerosol mass and composition from general-purpose aerosol measurements. Through analyzing the chemical and physical characteristics of aerosol observations during satellite-detected dust episodes, we select five indicators to be used to identify local dust records: (1) high PM10 concentrations; (2) low PM2.5/PM10 ratio; (3) higher concentrations and percentage of crustal elements; (4) lower percentage of anthropogenic pollutants; and (5) low enrichment factors of anthropogenic elements. After establishing these identification criteria, we conduct hierarchical cluster analysis for all validated aerosol measurement data over 68 IMPROVE sites in the Western United States. A total of 182 local dust events were identified over 30 of the 68 locations from 2000 to 2007. These locations are either close to the four US Deserts, namely the Great Basin Desert, the Mojave Desert, the Sonoran Desert, and the Chihuahuan Desert, or in the high wind power region (Colorado). During the eight-year study period, the total number of dust events displays an interesting four-year activity cycle (one in 2000-2003 and the other in 2004-2007). The years of 2003, 2002 and 2007 are the three most active dust periods, with 46, 31 and 24 recorded dust events, respectively, while the years of 2000, 2004 and 2005 are the calmest periods, all with single digit dust records. Among these deserts, the Chihuahua Desert (59 cases) and the Sonoran Desert (62 cases) are by far the most active

  4. Characterization of events by aerosol mass size distributions.

    PubMed

    Nicolás, José; Yubero, Eduardo; Galindo, Nuria; Giménez, Joaquín; Castañer, Ramón; Carratalá, Adoración; Crespo, Javier; Pastor, Carlos

    2009-02-01

    Continuous measurements of particle mass size distributions were carried out in summer 2004 at an urban location in the western Mediterranean using an optical particle counter. In this work we propose a simple methodology to identify PM episodes and determine their influence on mass size distributions. During the study period three types of event produced a significant increase in TSP daily levels: Saharan dust intrusions, firework displays and strong winds, modifying size distributions in different ways. As well, a traffic-related mass size spectrum was obtained showing road dust particles injected into the atmosphere by vehicle-induced resuspension having mainly aerodynamic diameters between 5 and 15 microm. This was confirmed by principal component and conditional probability function analyses.

  5. Dispersion and transport of tropospheric aerosol and pollutants in the Western Mediterranean: the role of the Po Valley under different transport regimes

    NASA Astrophysics Data System (ADS)

    Bucci, Silvia; Fierli, Federico; Ravetta, François; Raut, Jean Christophe; Cristofanelli, Paolo; Decesari, Stefano; Diliberto, Luca; Größ, Johannes; Pap, Ines; Weinhold, Kay; Wiedensohler, Alfred; Cairo, Francesco

    2016-04-01

    This work reports a characterization of the vertical variability of tropospheric aerosol and gaseous pollutants, over the western Mediterranean, during the 2012 summer season. In particular, we investigate the role of the Po Valley region as a receptor and emissive region of both natural and anthropogenic aerosol. The observational analysis, based on a comprehensive database of meteorological, aerosol and chemical measurements, is integrated with a model analysis using the Lagrangian transport system FLEXPART combined with emission databases, and WRF-Chem, the Weather Research and Forecasting (WRF) model coupled with Chemistry. Observations have been performed in the framework of the Supersito project by Regional Agency of Prevention and Environment of the Emilia Romagna region (ARPA-ER, Ital), the TRAQA campaign (TRAnsport et Qualité de l'Air au dessus du bassin Méditerranéen) performed in the ChArMEx (Chemistry-Aerosol Mediterranean Experiment) project, and the european project PEGASOS (Pan-European Gas-AeroSOl-climate interaction Study). An alternation between different transport regimes characterized the 2012 summer, resulting in a large variability of aerosol and pollution at different time and spatial scales. Particles of different nature have been discriminated basing on optical properties retrieved from lidar data and supported by in-situ observations and transport analysis. Results show that, during the analysed season, aerosol in the Po Valley was mainly confined below 2000 m and dominated (50% of detections) by spherical particles. Two events of dust advection from northern Africa were identified (19th-21th June and 29th June-2nd July), with intrusion and mixing with local pollution in the PBL and a non-negligible occurrence (~7%) of dust at the ground. Frequent events (22% of occurrence) of non-spherical particles resuspension, likely due to uplift of mineral soil particles, were observed from the ground to 2000 m during afternoon and evening. In the

  6. Regional Aerosol Optical Properties and Radiative Impact of the Extreme Smoke Event in the European Arctic in Spring 2006

    NASA Technical Reports Server (NTRS)

    Lund Myhre, C.; Toledano, C.; Myhre, G.; Stebel, K.; Yttri, K.; Aaltonen, V.; Johnsrud, M.; Frioud, M.; Cachorro, V.; deFrutos, A.; Lihavainen, H.; Campbell, J.; Chaikovsky, A.; Shiobara, M.; Welton, E.; Torseth, K.

    2007-01-01

    In spring 2006 a special meteorological situation occurred in the European Arctic region giving record high levels of air pollution. The synoptic situation resulted in extensive transport of pollution predominantly from agricultural fires in Eastern Europe into the Arctic region and record high air-pollution levels were measured at the Zeppelin observatory at Ni-Alesun(78deg 54'N, 11deg 53'E) in the period from 25 April to 12 May. In the present study we investigate the optical properties of the aerosols from this extreme event and we estimate the radiative forcing of this episode. We examine the aerosol optical properties from the source region and into the European Arctic and explore the evolution of the episode and the changes in the optical properties. A number of sites in Eastern Europe, Northern Scandinavia and Svalbard are included in the study. In addition to AOD measurements, we explored lidar measurements from Minsk, ALOMAR (Arctic Lidar Observatory for Middle Atmosphere Research at Andenes) and Ny-Alesund. For the AERONET sites included (Minsk, Toravere, Hornsund) we have further studied the evolution of the aerosol size. Importantly, at Svalbard it is consistency between the AERONET measurements and calculations of single scattering albedo based on aerosol chemical composition. We have found strong agreement between the satellite dally MODIS AOD and the ground-based AOD observations. This agreement is crucial for the radiative forcing calculations. We calculate a strong negative radiative forcing for the most polluted days employing the analysed ground based data, MODIS AOD and a multi-stream model for radiative transfer of solar radiation.

  7. Monitoring and tracking the trans-Pacific transport of aerosols using multi-satellite aerosol optical depth composites

    NASA Astrophysics Data System (ADS)

    Naeger, Aaron R.; Gupta, Pawan; Zavodsky, Bradley T.; McGrath, Kevin M.

    2016-06-01

    The primary goal of this study was to generate a near-real time (NRT) aerosol optical depth (AOD) product capable of providing a comprehensive understanding of the aerosol spatial distribution over the Pacific Ocean, in order to better monitor and track the trans-Pacific transport of aerosols. Therefore, we developed a NRT product that takes advantage of observations from both low-earth orbiting and geostationary satellites. In particular, we utilize AOD products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) satellites. Then, we combine these AOD products with our own retrieval algorithms developed for the NOAA Geostationary Operational Environmental Satellite (GOES-15) and Japan Meteorological Agency (JMA) Multi-functional Transport Satellite (MTSAT-2) to generate a NRT daily AOD composite product. We present examples of the daily AOD composite product for a case study of trans-Pacific transport of Asian pollution and dust aerosols in mid-March 2014. Overall, the new product successfully tracks this aerosol plume during its trans-Pacific transport to the west coast of North America as the frequent geostationary observations lead to a greater coverage of cloud-free AOD retrievals equatorward of about 35° N, while the polar-orbiting satellites provide a greater coverage of AOD poleward of 35° N. However, we note several areas across the domain of interest from Asia to North America where the GOES-15 and MTSAT-2 retrieval algorithms can introduce significant uncertainties into the new product.

  8. A new Isotope Tracer to Identify Long Range Transport and Transformation of Aerosol

    NASA Astrophysics Data System (ADS)

    Shaheen, R.; Abramian, A.; Dominguez, G.; Bluen, B.; Jackson, T.; Thiemens, M. H.

    2007-12-01

    It is of interest to understand the intercontinental transport of dust particles because they can accumulate anthropogenic nitrate, sulphate and carbonaceous compounds (black carbon and aromatic hydrocarbon) on their surfaces by adsorption during transportation. Carbonate is a prominent component of the soils in north western China where much of the Asian dust is produced. Carbonate can affect atmospheric chemical processes and aerosol characteristics because the acid neutralizing capacity of this species facilitates the heterogeneous conversion of sulphate and nitrate The primary goal of this work is to develop an isotope methodology for carbonates that can be used as a chemical marker for the origin of polluted air plumes. The results will be compared with other established tracers such as nitrate and sulphate that possess anomalous oxygen isotopic composition in polluted environments from reaction with ozone. Aerosol samples were collected on filter papers using Anderson Cascade Impactors at two different locations in La Jolla, California: one at the Scripps Pier and the other one at coastal Mount Soledad (800 ft). The particulate samples were allowed to react with excess H3PO4 at 28 oC for 14h and the gaseous compounds released were collected at liquid nitrogen. CO2 gas was separated from other reaction products by gas chromatography. In order to measure the oxygen isotope composition, CO2 gas was fluorinated to release oxygen gas to be analysed on the isotope ratio mass spectrometer. We discuss the carbon and oxygen isotope composition of the CO2 released from the fine (< 1 um) and coarse (> 1um) particles collected at two different sites (Mt. Soledad and Scripps Pier) and its utility as a tracer to identify the long range transport of aerosol from local pollution events. The secondary organic oxidation products and concomitant isotope may provide a new indicator of chemical transformation. The transport situation of the air parcels will be analyzed through

  9. Investigation of the time evolved spatial distribution of urban PM2.5 concentrations and aerosol composition during episodic high PM events in Yuma, AZ

    NASA Astrophysics Data System (ADS)

    Holmes, Heather A.; Pardyjak, Eric R.; Tyler, Bonnie J.; Peterson, Richard E.

    An interdisciplinary field study designed to investigate the spatial and temporal variability of atmospheric aerosols during high particulate matter ( PM) events along the US-Mexico border near Yuma, AZ was run during the week of March 18, 2007. The experiments were designed to quantify chemical composition and physical phenomena governing the transport of aerosols generated from episodic high PM events. The field study included two micrometeorological monitoring sites; one rural and one urban, equipped with sonic anemometers, continuous particulate concentration monitors and ambient aerosol collection equipment. In addition to the two main monitoring sites, five additional locations were equipped with optical particle counters to allow for the investigation of the spatial and temporal distribution of PM2.5 in the urban environment. In this paper, the meteorological and turbulence parameters governing the distribution and concentration of PM2.5 in the urban environment for two high-wind erosion events and one burning event are compared. The interaction between local atmospheric conditions and the particulate distribution is investigated. Results indicate that a single point measurement in the urban area of Yuma may not be sufficient for determining the ambient PM concentrations that the local population experiences; all three high PM events indicated PM2.5 varied considerably with maximum urban concentrations 5-10 times greater than the measured minima. A comparison of inorganic and carbonaceous content of the aerosols for the three high PM events is presented. The comparison shows an increase in silicon during crustal dust events and an increase in elemental and organic carbon during the burn event. Additional surface chemistry analysis, using time-of-flight secondary ion mass spectrometry (ToF-SIMS), for aerosols collected at the urban and rural sites during the burn event are discussed. The surface chemistry analysis provides positive ion mass spectra of organic

  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. Climatology of the aerosol optical depth by components from the Multiangle Imaging SpectroRadiometer (MISR) and a high-resolution chemistry transport model

    NASA Astrophysics Data System (ADS)

    Lee, H.; Kalashnikova, O. V.; Suzuki, K.; Braverman, A.; Garay, M. J.; Kahn, R. A.

    2015-12-01

    The Multi-angle Imaging SpectroRadiometer (MISR) Joint Aerosol (JOINT_AS) Level 3 product provides a global, descriptive summary of MISR Level 2 aerosol optical depth (AOD) and aerosol type information for each month between March 2000 and the present. Using Version 1 of JOINT_AS, which is based on the operational (Version 22) MISR Level 2 aerosol product, this study analyzes, for the first time, characteristics of observed and simulated distributions of AOD for three broad classes of aerosols: non-absorbing, absorbing, and non-spherical - near or downwind of their major source regions. The statistical moments (means, standard deviations, and skewnesses) and distributions of AOD by components derived from the JOINT_AS are compared with results from the SPectral RadIatioN-TrAnSport (SPRINTARS) model, a chemistry transport model (CTM) with very high spatial and temporal resolution. Overall, the AOD distributions of combined MISR aerosol types show good agreement with those from SPRINTARS. Marginal distributions of AOD for each aerosol type in both MISR and SPRINTARS show considerable high positive skewness, which indicates the importance of including extreme AOD events when comparing satellite retrievals with models. The MISR JOINT_AS product will greatly facilitate comparisons between satellite observations and model simulations of aerosols by type.

  12. REPRESENTING AEROSOL DYNAMICS AND PROPERTIES IN CHEMICAL TRANSPORT MODELS BY THE METHOD OF MOMENTS.

    SciTech Connect

    SCHWARTZ, S.E.; MCGRAW, R.; BENKOVITZ, C.M.; WRIGHT, D.L.

    2001-04-01

    Atmospheric aerosols, suspensions of solid or liquid particles, are an important multi-phase system. Aerosols scatter and absorb shortwave (solar) radiation, affecting climate (Charlson et al., 1992; Schwartz, 1996) and visibility; nucleate cloud droplet formation, modifying the reflectivity of clouds (Twomey et al., 1984; Schwartz and Slingo, 1996) as well as contributing to composition of cloudwater and to wet deposition (Seinfeld and Pandis, 1998); and affect human health through inhalation (NRC, 1998). Existing and prospective air quality regulations impose standards on concentrations of atmospheric aerosols to protect human health and welfare (EPA, 1998). Chemical transport and transformation models representing the loading and geographical distribution of aerosols and precursor gases are needed to permit development of effective and efficient strategies for meeting air quality standards, and for examining aerosol effects on climate retrospectively and prospectively for different emissions scenarios. Important aerosol properties and processes depend on their size distribution: light scattering, cloud nucleating properties, dry deposition, and penetration into airways of lungs. The evolution of the mass loading itself depends on particle size because of the size dependence of growth and removal processes. For these reasons it is increasingly recognized that chemical transport and transformation models must represent not just the mass loading of atmospheric particulate matter but also the aerosol microphysical properties and the evolution of these properties if aerosols are to be accurately represented in these models. If the size distribution of the aerosol is known, a given property can be evaluated as the integral of the appropriate kernel function over the size distribution. This has motivated the approach of determining aerosol size distribution, and of explicitly representing this distribution and its evolution in chemical transport models.

  13. Uncertainties in aerosol direct and indirect effects attributed to uncertainties in convective transport parameterizations

    NASA Astrophysics Data System (ADS)

    Storelvmo, T.

    2012-11-01

    Deep convection is an important transport mechanism for aerosol particles, allowing them to be lifted to levels where they are subject to long-range transport from source regions to remote regions. The sensitivity of regional aerosol effects to the rate of entrainment in deep moist convection has been explored in a global modeling framework, and found to be crucial for the radiative balance both at the surface and at the top of the atmosphere. The fact that regions where deep convection is frequent often coincide with regions of particularly high black carbon emissions is found to be an important factor in understanding this sensitivity to entrainment. More entrainment leads to shallower convective plumes and less aerosol transport from the boundary layer to the upper troposphere in source regions. As a result, boundary layer aerosol concentrations are increased in source regions, while upper tropospheric aerosol concentrations are reduced globally. This generally leads to stronger aerosol effects in polluted regions and weaker aerosol effects in remote regions. Because black carbon particles have the ability to absorb solar radiation, reducing their concentration leads to more solar radiation reflected back to space, especially over bright surfaces. Conversely, at the surface more entrainment means more downwelling shortwave radiation everywhere but in source regions. Regions that experience increased aerosol concentrations in the boundary layer in response to increased entrainment observed a stronger aerosol indirect effect, while the opposite was true everywhere else. This study highlights that the relative strengths of the aerosol direct and indirect effects in clean versus polluted regions depend crucially on the rate of entrainment in deep convective clouds, a process that is presently not well understood and quantified.

  14. Dust transport over the eastern Mediterranean derived from Total Ozone Mapping Spectrometer, Aerosol Robotic Network, and surface measurements

    NASA Astrophysics Data System (ADS)

    Kalivitis, N.; Gerasopoulos, E.; Vrekoussis, M.; Kouvarakis, G.; Kubilay, N.; Hatzianastassiou, N.; Vardavas, I.; Mihalopoulos, N.

    2007-02-01

    Multiyear surface PM10 measurements performed on Crete Island, Greece, have been used in conjunction with satellite (Total Ozone Mapping Spectrometer (TOMS)) and ground-based remote sensing measurements (Aerosol Robotic Network (AERONET)) to enhance our understanding of the evolution of mineral dust events over the eastern Mediterranean. An analysis of southerly air masses at altitudes of 1000 and 3000 m over a 5 year period (2000-2005), showed that dust can potentially arrive over Crete, either simultaneously in the lower free troposphere and inside the boundary layer (vertical extended transport (VET)) or initially into the free troposphere with the heavier particles gradually being scavenged inside the boundary layer (free troposphere transport (FTT)). Both pathways present significant seasonal variations but on an annual basis contribute almost equally to the dust transport in the area. During VET the aerosol index (AI) derived from TOMS was significantly correlated with surface PM10, and in general AI was found to be adequate for the characterization of dust loadings over the eastern Mediterranean on a climatological basis. A significant covariance between PM10 and AOT was observed during VET as well, indicating that AOT levels from AERONET may be estimated by PM10 levels at the surface. Surface measurements are thus crucial for the validation of remote sensing measurements and hence are a powerful tool for the investigation of the impact of aerosols on climate.

  15. Research of transport and deposition of aerosol in human airway replica

    NASA Astrophysics Data System (ADS)

    Lizal, Frantisek; Jedelsky, Jan; Elcner, Jakub; Durdina, Lukas; Halasova, Tereza; Mravec, Filip; Jicha, Miroslav

    2012-04-01

    Growing concern about knowledge of aerosol transport in human lungs is caused by great potential of use of inhaled pharmaceuticals. Second substantial motive for the research is an effort to minimize adverse effects of particular matter emitted by traffic and industry on human health. We created model geometry of human lungs to 7th generation of branching. This model geometry was used for fabrication of two physical models. The first one is made from thin walled transparent silicone and it allows a measurement of velocity and size of aerosol particles by Phase Doppler Anemometry (PDA). The second one is fabricated by stereolithographic method and it is designed for aerosol deposition measurements. We provided a series of measurements of aerosol transport in the transparent model and we ascertained remarkable phenomena linked with lung flow. The results are presented in brief. To gather how this phenomena affects aerosol deposition in human lungs we used the second model and we developed a technique for deposition fraction and deposition efficiency assessment. The results confirmed that non-symmetric and complicated shape of human airways essentially affects transport and deposition of aerosol. The research will now focus on deeper insight in aerosol deposition.

  16. Long-range Transport of Aerosol at a Mountain Site in the Western Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Roberts, Greg; Corrigan, Craig; Ritchie, John; Pont, Véronique; Claeys, Marine; Sciare, Jean; Dulac, François

    2016-04-01

    The Mediterranean Region has been identified as sensitive to changes in the hydrological cycle, which could affect the water resources for millions of people by the turn of the century. However, prior to recent observations, most climate models have not accounted for the impacts of aerosol in this region. Past airborne studies have shown that aerosol sources from Europe and Africa are often transported throughout the lower troposphere; yet, because of their complex vertical distribution, it is a challenge to capture the variability and quantify the contribution of these sources to the radiative budget and precipitation processes. The PAEROS ChArMEx Mountain Experiment (PACMEx) complemented the regional activities by collecting aerosol data from atop a mountain on the island of Corsica, France in order to assess boundary layer / free troposphere atmospheric processes. In June/July 2013, PACMEx instruments were deployed at 2000 m.asl near the center of Corsica, France to complement ground-based aerosol observations at 550 m.asl on the northern peninsula, as well as airborne measurements. Comparisons between the peninsula site and the mountain site show similar general trends in aerosol properties; yet, differences in aerosol properties reveal the myriad transport mechanisms over the Mediterranean Basin. Using aerosol physicochemical data coupled with back trajectory analysis, different sources have been identified including Saharan dust transport, residual dust mixed with sea salt, anthropogenic emissions from Western Europe, and a period of biomass burning from Eastern Europe. Each period exhibits distinct signatures in the aerosol related to transport processes above and below the boundary layer. In addition, the total aerosol concentrations at the mountain site revealed a strong diurnal cycling the between the atmospheric boundary layer and the free troposphere, which is typical of mountain-top observations. PACMEx was funded by the National Science Foundation

  17. Transport and Evolution of Aerosol Above/Below the Boundary Layer in the Western Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Roberts, G. C.; Corrigan, C.; Ritchie, J.; Pont, V.; Claeys, M.; Sciare, J.; Mallet, M.; Dulac, F.

    2014-12-01

    The Mediterranean Region has been identified as sensitive to changes in the hydrological cycle, which could affect the water resources for millions of people by the turn of the century. However, prior to recent observations, most climate models have not accounted for the impacts of aerosol in this region. Past airborne studies have shown that aerosol sources from Europe and Africa are often transported throughout the lower troposphere; yet, because of their complex vertical distribution, it is a challenge to capture the variability and quantify the contribution of these sources to the radiative budget and precipitation processes. The PAEROS ChArMEx Mountain Experiment (PACMEx) complemented the regional activities of the ChArMEx/ADRIMED summer 2013 campaign by collecting aerosol data from atop a mountain on the island of Corsica, France in order to assess boundary layer / free troposphere atmospheric processes. In June/July 2013, PACMEx instruments were deployed at 2000 m.asl near the center of Corsica to complement ground-based aerosol observations at 550 m.asl on the northern peninsula, as well as airborne measurements. Comparisons between the peninsula site and the mountain site show similar general trends in aerosol properties; yet, differences in aerosol properties reveal the myriad transport mechanisms over the Mediterranean Basin. Using aerosol physicochemical data coupled with back trajectory analysis, different sources have been identified including Saharan dust transport, residual dust mixed with sea salt, anthropogenic emissions from Western Europe, and a period of biomass burning from Eastern Europe. Each period exhibits distinct signatures in the aerosol related to transport processes above and below the boundary layer. In addition, the total aerosol concentrations at the mountain site revealed a strong diurnal cycling between the atmospheric boundary layer and the free troposphere, which is typical of mountain-top observations. PACMEx was funded by the

  18. HSRL-2 Observations of Aerosol Variability During an Aerosol Build-up Event in Houston and Comparisons With WRF-Chem

    NASA Technical Reports Server (NTRS)

    Burton, Sharon P.; Saide, Pablo; Sawamura, Patricia; Hostetler, Chris; Ferrare, Rich; Scarino, Amy Jo; Berkoff, Tim; Harper, David; Cook, Tony; Rogers, Ray; Carmichael, Greg

    2015-01-01

    The NASA Langley airborne multi-wavelength High Spectral Resolution Lidar (HSRL-2) provides vertical distribution of aerosol optical properties as curtains of aerosol extinction, backscatter and depolarization along the flight track, plus intensive properties that are used to infer aerosol type and external mixing of types. Deployed aboard the NASA Langley King Air on the DISCOVER-AQ field mission in Houston in September 2013, HSRL-2 flew a pattern that included 18 ground sites, repeated four times a day, coordinated with a suite of airborne in situ measurements. The horizontally and vertically resolved curtains of HSRL-2 measurements give an unparalleled view of the spatial and temporal variability of aerosol, which provide broad context for interpreting other measurements and models. Detailed comparisons of aerosol extinction are made with the WRF-Chem chemical transport model along the HSRL-2 flight path. The period from Sept. 11-14 is notable for a large aerosol build-up and persistent smoke layers. We investigate the aerosol properties using the vertically resolved HSRL-2 measurements and aerosol typing analysis plus WRFChem model tracers and back trajectories, and modeling of humidification effects.

  19. Colorado air quality impacted by long-range-transported aerosol: a set of case studies during the 2015 Pacific Northwest fires

    NASA Astrophysics Data System (ADS)

    Creamean, Jessie M.; Neiman, Paul J.; Coleman, Timothy; Senff, Christoph J.; Kirgis, Guillaume; Alvarez, Raul J.; Yamamoto, Atsushi

    2016-09-01

    Biomass burning plumes containing aerosols from forest fires can be transported long distances, which can ultimately impact climate and air quality in regions far from the source. Interestingly, these fires can inject aerosols other than smoke into the atmosphere, which very few studies have evidenced. Here, we demonstrate a set of case studies of long-range transport of mineral dust aerosols in addition to smoke from numerous fires (including predominantly forest fires and a few grass/shrub fires) in the Pacific Northwest to Colorado, US. These aerosols were detected in Boulder, Colorado, along the Front Range using beta-ray attenuation and energy-dispersive X-ray fluorescence spectroscopy, and corroborated with satellite-borne lidar observations of smoke and dust. Further, we examined the transport pathways of these aerosols using air mass trajectory analysis and regional- and synoptic-scale meteorological dynamics. Three separate events with poor air quality and increased mass concentrations of metals from biomass burning (S and K) and minerals (Al, Si, Ca, Fe, and Ti) occurred due to the introduction of smoke and dust from regional- and synoptic-scale winds. Cleaner time periods with good air quality and lesser concentrations of biomass burning and mineral metals between the haze events were due to the advection of smoke and dust away from the region. Dust and smoke present in biomass burning haze can have diverse impacts on visibility, health, cloud formation, and surface radiation. Thus, it is important to understand how aerosol populations can be influenced by long-range-transported aerosols, particularly those emitted from large source contributors such as wildfires.

  20. Microphysical properties of transported biomass burning aerosols in coastal regions, and application to improving retrievals of aerosol optical depth from SeaWiFS data

    NASA Astrophysics Data System (ADS)

    Sayer, A. M.; Hsu, N. C.; Bettenhausen, C.

    2013-05-01

    Due to the limited measurement capabilities of heritage and current spaceborne passive imaging radiometers, algorithms for the retrieval of aerosol optical depth (AOD) and related quantities must make assumptions relating to aerosol microphysical properties and surface reflectance. Over the ocean, surface reflectance can be relatively well-modelled, but knowledge of aerosol properties can remain elusive. Several field campaigns and many studies have examined the microphysical properties of biomass burning (smoke) aerosol. However, these largely focus on properties over land and near to the source regions. In coastal and open-ocean regions the properties of transported smoke may differ, due to factors such as aerosol aging, wet/dry deposition, and mixture with other aerosol sources (e.g. influence of maritime, pollution, or mineral dust aerosols). Hence, models based on near-source aerosol observations may be less representative of such transported smoke aerosols, introducing additional uncertainty into satellite retrievals of aerosol properties. This study examines case studies of transported smoke from select globally-distributed coastal and island Aerosol Robotic Network (AERONET) sites. These are used to inform improved models for over-ocean transported smoke aerosol for AOD retrievals from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). These models are used in an updated version of the SeaWiFS Ocean Aerosol Retrieval (SOAR) algorithm, which has been combined with the Deep Blue algorithm over land to create a 13-year (1997-2010) high-quality record of AOD over land and ocean. Applying these algorithms to other sensors will enable the creation of a long-term global climate data record of spectral AOD.

  1. New Measurements of Aerosol Vertical Structure from Space using the NASA Geoscience Laser Altimeter System (GLAS): Applications for Aerosol Transport Models

    NASA Technical Reports Server (NTRS)

    Welton, E. J.; Spinhime, J.; Palm, S.; Hlavka, D.; Hart, W.; Ginoux, P.; Chin, M.; Colarco, P.

    2004-01-01

    In the past, satellite measurements of aerosols have only been possible using passive sensors. Analysis of passive satellite data has lead to an improved understanding of aerosol properties, spatial distribution, and their effect on the earth,s climate. However, direct measurement of aerosol vertical distribution has not been possible using only the passive data. Knowledge of aerosol vertical distribution is important to correctly assess the impact of aerosol absorption, for certain atmospheric correction procedures, and to help constrain height profiles in aerosol transport models. On January 12,2003 NASA launched the first satellite-based lidar, the Geoscience Laser Altimeter System (GLAS), onboard the ICESat spacecraft. GLAS is both an altimeter and an atmospheric lidar, and obtains direct measurements of aerosol and cloud heights. Here we show an overview of GLAS, provide an update of its current status, and discuss how GLAS data will be useful for modeling efforts. In particular, a strategy of using GLAS to characterize the height profile of dust plumes over source regions will be presented, along with initial results. Such information can be used to validate and improve output from aerosol transport models. Aerosol height profile comparisons between GLAS and transport models will be shown for regions downwind of aerosol sources. We will also discuss the feasibility of assimilating GLAS profiles into the models in order to improve their output.

  2. New Measurements of Aerosol Vertical Structure from Space Using the NASA Geoscience Laser Altimeter System (GLAS): Applications for Aerosol Transport Models

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; Ginoux, Paul; Colarco, Peter; Chin, Mian; Spinhirne, James D.; Palm, Steven P.; Hlavka, Dennis; Hart, William

    2003-01-01

    In the past, satellite measurements of aerosols have only been possible using passive sensors. Analysis of passive satellite data has lead to an improved understanding of aerosol properties, spatial distribution, and their effect on the earth s climate. However, direct measurement of aerosol vertical distribution has not been possible using only the passive data. Knowledge of aerosol vertical distribution is important to correctly assess the impact of aerosol absorption, for certain atmospheric correction procedures, and to help constrain height profiles in aerosol transport models. On January 12,2003 NASA launched the first satellite-based lidar, the Geoscience Laser Altimeter System (GLAS), onboard the ICESat spacecraft. GLAS is both an altimeter and an atmospheric lidar, and obtains direct measurements of aerosol and cloud heights. Here we show an overview of GLAS, provide an update of its current status, and discuss how GUS data will be useful for modeling efforts. In particular, a strategy of using GLAS to characterize the height profile of dust plumes over source regions will be presented, along with initial results. Such information can be used to validate and improve output from aerosol transport models. Aerosol height profile comparisons between GLAS and transport models will be shown for regions downwind of aerosol sources. We will also discuss the feasibility of assimilating GLAS profiles into the models in order to improve their output,

  3. High-resolution MODIS aerosol retrieval during wildfire events in California for use in exposure assessment

    NASA Astrophysics Data System (ADS)

    Raffuse, Sean M.; McCarthy, Michael C.; Craig, Kenneth J.; DeWinter, Jennifer L.; Jumbam, Loayeh K.; Fruin, Scott; James Gauderman, W.; Lurmann, Frederick W.

    2013-10-01

    Retrieval of aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) using the Collection 5 (C005) algorithm provides large-scale (10 × 10 km) estimates that can be used to predict surface layer concentrations of particulate matter with aerodynamic diameter smaller than 2.5 µm (PM2.5). However, these large-scale estimates are not suitable for identifying intraurban variability of surface PM2.5 concentrations during wildfire events when individual plumes impact populated areas. We demonstrate a method for providing high-resolution (2.5 km) kernel-smoothed estimates of AOD over California during the 2008 northern California fires. The method uses high-resolution surface reflectance ratios of the 0.66 and 2.12 µm channels, a locally derived aerosol optical model characteristic of fresh wildfire plumes, and a relaxed cloud filter. Results show that the AOD derived for the 2008 northern California fires outperformed the standard product in matching observed aerosol optical thickness at three coastal Aerosol Robotic Network sites and routinely explained more than 50% of the variance in hourly surface PM2.5 concentrations observed during the wildfires.

  4. Occurrence of weak, sub-micron, tropospheric aerosol events at high Arctic latitudes

    NASA Astrophysics Data System (ADS)

    O'Neill, N. T.; Pancrati, O.; Baibakov, K.; Eloranta, E.; Batchelor, R. L.; Freemantle, J.; McArthur, L. J. B.; Strong, K.; Lindenmaier, R.

    2008-07-01

    Numerous fine mode (sub-micron) aerosol optical events were observed during the summer of 2007 at the High Arctic atmospheric observatory (PEARL) located at Eureka, Nunavut, Canada. Half of these events could be traced to forest fires in southern and eastern Russia and the Northwest Territories of Canada. The most notable findings were that (a) a combination of ground-based measurements (passive sunphotometry, high spectral resolution lidar) could be employed to determine that weak (near sub-visual) fine mode events had occurred, and (b) this data combined with remote sensing imagery products (MODIS, OMI-AI, FLAMBE fire sources), Fourier transform spectroscopy and back trajectories could be employed to identify the smoke events.

  5. Effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events

    NASA Astrophysics Data System (ADS)

    Quan, Jiannong; Liu, Quan; Li, Xia; Gao, Yang; Jia, Xingcan; Sheng, Jiujiang; Liu, Yangang

    2015-12-01

    The effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events was investigated by analysis of comprehensive measurements of aerosol composition and concentrations [e.g., particular matters (PM2.5), nitrate (NO3), sulfate (SO4), ammonium (NH4)], gas-phase precursors [e.g., nitrogen oxides (NOx), sulfur dioxide (SO2), and ozone (O3)], and relevant meteorological parameters [e.g., visibility and relative humidity (RH)]. The measurements were conducted in Beijing, China from Sep. 07, 2012 to Jan. 16, 2013. The results show that the conversion ratios of N from NOx to nitrate (Nratio) and S from SO2 to sulfate (Sratio) both significantly increased in haze events, suggesting enhanced conversions from NOx and SO2 to their corresponding particle phases in the late haze period. Further analysis shows that Nratio and Sratio increased with increasing RH, with Nratio and Sratio being only 0.04 and 0.03, respectively, when RH < 40%, and increasing up to 0.16 and 0.12 when RH reached 60-80%, respectively. The enhanced conversion ratios of N and S in the late haze period is likely due to heterogeneous aqueous reactions, because solar radiation and thus the photochemical capacity are reduced by the increases in aerosols and RH. This point was further affirmed by the relationships of Nratio and Sratio to O3: the conversion ratios increase with decreasing O3 concentration when O3 concentration is lower than <15 ppb but increased with increasing O3 when O3 concentration is higher than 15 ppb. The results suggest that heterogeneous aqueous reactions likely changed aerosols and their precursors during the haze events: in the beginning of haze events, the precursor gases accumulated quickly due to high emission and low reaction rate; the occurrence of heterogeneous aqueous reactions in the late haze period, together with the accumulated high concentrations of precursor gases such as SO2 and NOx, accelerated the formation of secondary

  6. Effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events

    DOE PAGES

    Quan, Jiannong; Liu, Yangang; Liu, Quan; Li, Xia; Gao, Yang; Jia, Xingcan; Sheng, Jiujiang

    2015-09-30

    In this study, the effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events was investigated by analysis of comprehensive measurements of aerosol composition and concentrations [e.g., particular matters (PM2.5), nitrate (NO3), sulfate (SO4), ammonium (NH4)], gas-phase precursors [e.g., nitrogen oxides (NOx), sulfur dioxide (SO2), and ozone (O3)], and relevant meteorological parameters [e.g., visibility and relative humidity (RH)]. The measurements were conducted in Beijing, China from Sep. 07, 2012 to Jan. 16, 2013. The results show that the conversion ratios of N from NOx to nitrate (Nratio) and S from SO2 to sulfate (Sratio) bothmore » significantly increased in haze events, suggesting enhanced conversions from NOx and SO2 to their corresponding particle phases in the late haze period. Further analysis shows that Nratio and Sratio increased with increasing RH, with Nratio and Sratio being only 0.04 and 0.03, respectively, when RH < 40%, and increasing up to 0.16 and 0.12 when RH reached 60–80%, respectively. The enhanced conversion ratios of N and S in the late haze period is likely due to heterogeneous aqueous reactions, because solar radiation and thus the photochemical capacity are reduced by the increases in aerosols and RH. This point was further affirmed by the relationships of Nratio and Sratio to O3: the conversion ratios increase with decreasing O3 concentration when O3 concentration is lower than <15 ppb but increased with increasing O3 when O3 concentration is higher than 15 ppb. The results suggest that heterogeneous aqueous reactions likely changed aerosols and their precursors during the haze events: in the beginning of haze events, the precursor gases accumulated quickly due to high emission and low reaction rate; the occurrence of heterogeneous aqueous reactions in the late haze period, together with the accumulated high concentrations of precursor gases such as SO2 and NOx, accelerated the

  7. Effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events

    SciTech Connect

    Quan, Jiannong; Liu, Yangang; Liu, Quan; Li, Xia; Gao, Yang; Jia, Xingcan; Sheng, Jiujiang

    2015-09-30

    In this study, the effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events was investigated by analysis of comprehensive measurements of aerosol composition and concentrations [e.g., particular matters (PM2.5), nitrate (NO3), sulfate (SO4), ammonium (NH4)], gas-phase precursors [e.g., nitrogen oxides (NOx), sulfur dioxide (SO2), and ozone (O3)], and relevant meteorological parameters [e.g., visibility and relative humidity (RH)]. The measurements were conducted in Beijing, China from Sep. 07, 2012 to Jan. 16, 2013. The results show that the conversion ratios of N from NOx to nitrate (Nratio) and S from SO2 to sulfate (Sratio) both significantly increased in haze events, suggesting enhanced conversions from NOx and SO2 to their corresponding particle phases in the late haze period. Further analysis shows that Nratio and Sratio increased with increasing RH, with Nratio and Sratio being only 0.04 and 0.03, respectively, when RH < 40%, and increasing up to 0.16 and 0.12 when RH reached 60–80%, respectively. The enhanced conversion ratios of N and S in the late haze period is likely due to heterogeneous aqueous reactions, because solar radiation and thus the photochemical capacity are reduced by the increases in aerosols and RH. This point was further affirmed by the relationships of Nratio and Sratio to O3: the conversion ratios increase with decreasing O3 concentration when O3 concentration is lower than <15 ppb but increased with increasing O3 when O3 concentration is higher than 15 ppb. The results suggest that heterogeneous aqueous reactions likely changed aerosols and their precursors during the haze events: in the beginning of haze events, the precursor gases accumulated quickly

  8. High secondary aerosol contribution to particulate pollution during haze events in China

    NASA Astrophysics Data System (ADS)

    Huang, Ru-Jin; Zhang, Yanlin; Bozzetti, Carlo; Ho, Kin-Fai; Cao, Jun-Ji; Han, Yongming; Daellenbach, Kaspar R.; Slowik, Jay G.; Platt, Stephen M.; Canonaco, Francesco; Zotter, Peter; Wolf, Robert; Pieber, Simone M.; Bruns, Emily A.; Crippa, Monica; Ciarelli, Giancarlo; Piazzalunga, Andrea; Schwikowski, Margit; Abbaszade, Gülcin; Schnelle-Kreis, Jürgen; Zimmermann, Ralf; An, Zhisheng; Szidat, Sönke; Baltensperger, Urs; Haddad, Imad El; Prévôt, André S. H.

    2014-10-01

    Rapid industrialization and urbanization in developing countries has led to an increase in air pollution, along a similar trajectory to that previously experienced by the developed nations. In China, particulate pollution is a serious environmental problem that is influencing air quality, regional and global climates, and human health. In response to the extremely severe and persistent haze pollution experienced by about 800 million people during the first quarter of 2013 (refs 4, 5), the Chinese State Council announced its aim to reduce concentrations of PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 micrometres) by up to 25 per cent relative to 2012 levels by 2017 (ref. 6). Such efforts however require elucidation of the factors governing the abundance and composition of PM2.5, which remain poorly constrained in China. Here we combine a comprehensive set of novel and state-of-the-art offline analytical approaches and statistical techniques to investigate the chemical nature and sources of particulate matter at urban locations in Beijing, Shanghai, Guangzhou and Xi'an during January 2013. We find that the severe haze pollution event was driven to a large extent by secondary aerosol formation, which contributed 30-77 per cent and 44-71 per cent (average for all four cities) of PM2.5 and of organic aerosol, respectively. On average, the contribution of secondary organic aerosol (SOA) and secondary inorganic aerosol (SIA) are found to be of similar importance (SOA/SIA ratios range from 0.6 to 1.4). Our results suggest that, in addition to mitigating primary particulate emissions, reducing the emissions of secondary aerosol precursors from, for example, fossil fuel combustion and biomass burning is likely to be important for controlling China's PM2.5 levels and for reducing the environmental, economic and health impacts resulting from particulate pollution.

  9. High secondary aerosol contribution to particulate pollution during haze events in China.

    PubMed

    Huang, Ru-Jin; Zhang, Yanlin; Bozzetti, Carlo; Ho, Kin-Fai; Cao, Jun-Ji; Han, Yongming; Daellenbach, Kaspar R; Slowik, Jay G; Platt, Stephen M; Canonaco, Francesco; Zotter, Peter; Wolf, Robert; Pieber, Simone M; Bruns, Emily A; Crippa, Monica; Ciarelli, Giancarlo; Piazzalunga, Andrea; Schwikowski, Margit; Abbaszade, Gülcin; Schnelle-Kreis, Jürgen; Zimmermann, Ralf; An, Zhisheng; Szidat, Sönke; Baltensperger, Urs; El Haddad, Imad; Prévôt, André S H

    2014-10-01

    Rapid industrialization and urbanization in developing countries has led to an increase in air pollution, along a similar trajectory to that previously experienced by the developed nations. In China, particulate pollution is a serious environmental problem that is influencing air quality, regional and global climates, and human health. In response to the extremely severe and persistent haze pollution experienced by about 800 million people during the first quarter of 2013 (refs 4, 5), the Chinese State Council announced its aim to reduce concentrations of PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 micrometres) by up to 25 per cent relative to 2012 levels by 2017 (ref. 6). Such efforts however require elucidation of the factors governing the abundance and composition of PM2.5, which remain poorly constrained in China. Here we combine a comprehensive set of novel and state-of-the-art offline analytical approaches and statistical techniques to investigate the chemical nature and sources of particulate matter at urban locations in Beijing, Shanghai, Guangzhou and Xi'an during January 2013. We find that the severe haze pollution event was driven to a large extent by secondary aerosol formation, which contributed 30-77 per cent and 44-71 per cent (average for all four cities) of PM2.5 and of organic aerosol, respectively. On average, the contribution of secondary organic aerosol (SOA) and secondary inorganic aerosol (SIA) are found to be of similar importance (SOA/SIA ratios range from 0.6 to 1.4). Our results suggest that, in addition to mitigating primary particulate emissions, reducing the emissions of secondary aerosol precursors from, for example, fossil fuel combustion and biomass burning is likely to be important for controlling China's PM2.5 levels and for reducing the environmental, economic and health impacts resulting from particulate pollution. PMID:25231863

  10. A Satellite-based Assessment of Trans-Pacific Transport of Pollution Aerosol

    NASA Technical Reports Server (NTRS)

    Yu, Hongbin; Remer, Lorraine; Chin, Mian; Bian, Huisheng; Kleidman, Richard; Diehl. Thomas

    2007-01-01

    It has been well documented that pollution aerosol and dust from East Asia can transport across the North Pacific basin, reaching North America and beyond. Such intercontinental transport extends the impact of aerosols for climate change, air quality, atmospheric chemistry, and ocean biology from local and regional scales to hemispheric and global scales. Long term, measurement-based studies are necessary to adequately assess the implications of these wider impacts. A satellite-based assessment can augment intensive field campaigns by expanding temporal and spatial scales and also serve as constraints for model simulations. Satellite imagers have been providing a wealth of evidence for the intercontinental transport of aerosols for more than two decades. Quantitative assessments, however, became feasible only recently as a result of the much improved measurement accuracy and enhanced new capabilities of satellite sensors. In this study, we generated a 4-year (2002 to 2005) climatology of optical depth for pollution aerosol (defined as a mixture of aerosols from urbanlindustrial pollution and biomass burning in this study) over the North Pacific from MODerate resolution Imaging Spectro-radiometer (MODIS) observations of fine- and coarse-mode aerosol optical depths. The pollution aerosol mass loading and fluxes were then calculated using measurements of the dependence of aerosol mass extinction efficiency on relative humidity and of aerosol vertical distributions from field campaigns and available satellite observations in the region. We estimated that about 18 Tg/year pollution aerosol is exported from East Asia to the northwestern Pacific Ocean, of which about 25% reaches the west coast of North America. The pollution fluxes are largest in spring and smallest in summer. For the period we have examined the strongest export and import of pollution particulates occurred in 2003, due largely to record intense Eurasia wildfires in spring and summer. The overall

  11. Influence of Aerosol Heating on the Stratospheric Transport of the Mt. Pinatubo Eruption

    NASA Technical Reports Server (NTRS)

    Aquila, Valentina; Oman, Luke D.; Stolarski, Richard S.

    2011-01-01

    On June 15th, 1991 the eruption of Mt. Pinatubo (15.1 deg. N, 120.3 Deg. E) in the Philippines injected about 20 Tg of sulfur dioxide in the stratosphere, which was transformed into sulfuric acid aerosol. The large perturbation of the background aerosol caused an increase in temperature in the lower stratosphere of 2-3 K. Even though stratospheric winds climatological]y tend to hinder the air mixing between the two hemispheres, observations have shown that a large part of the SO2 emitted by Mt. Pinatubo have been transported from the Northern to the Southern Hemisphere. We simulate the eruption of Mt. Pinatubo with the Goddard Earth Observing System (GEOS) version 5 global climate model, coupled to the aerosol module GOCART and the stratospheric chemistry module StratChem, to investigate the influence of the eruption of Mt. Pinatubo on the stratospheric transport pattern. We perform two ensembles of simulations: the first ensemble consists of runs without coupling between aerosol and radiation. In these simulations the plume of aerosols is treated as a passive tracer and the atmosphere is unperturbed. In the second ensemble of simulations aerosols and radiation are coupled. We show that the set of runs with interactive aerosol produces a larger cross-equatorial transport of the Pinatubo cloud. In our simulations the local heating perturbation caused by the sudden injection of volcanic aerosol changes the pattern of the stratospheric winds causing more intrusion of air from the Northern into the Southern Hemisphere. Furthermore, we perform simulations changing the injection height of the cloud, and study the transport of the plume resulting from the different scenarios. Comparisons of model results with SAGE II and AVHRR satellite observations will be shown.

  12. Aerosol chemistry during the wet season in central Amazonia - The influence of long-range transport

    NASA Technical Reports Server (NTRS)

    Talbot, R. W.; Andreae, M. O.; Berresheim, H.; Artaxo, P.; Garstang, M.

    1990-01-01

    The temporal variation in the concentration and chemistry of the atmospheric aerosol over central Amazonia, Brazil, during the 1987 wet season is discussed based on ground and aircraft collected data obtained during the NASA GTE ABLE 2B expedition conducted in April/May 1987. It is found that wet-season aerosol concentrations and composition are variable in contrast to the more uniform biogenic aerosol observed during the 1985 dry season; four distinct intervals of enhanced aerosol concentration coincided with short periods (3 to 5 d) of extensive rainfall. It is hypothesized that aerosol chemistry in Amazonia during the wet season is strongly influenced by long-range transport of soil dust, marine aerosol, and possibly biomass combustion products advected into the central Basin by large-scale tropospheric circulation, producing periodic pulses of material input to local boundary layer air. The resultant wet-season aerosol regime is dynamic, in contrast to the uniformity of natural biogenic aerosols during the dry season.

  13. Application of natural radionuclides for determination of tropospheric ozone and aerosol transport.

    SciTech Connect

    Gaffney, J. S.; Marley, N. A.; Drayton, P. J.; Orlandini, K. A.

    2000-12-06

    Natural radionuclides have been proposed for use in assessing the transport of ozone and aerosols in the troposphere. For example, {sup 7}Be is known to be produced in the upper troposphere and lower stratosphere by interactions with cosmogenic particles. Beryllium-7 has a 53.28-day half-life and is a gamma emitter that attaches itself to fine particles in the atmosphere once it is formed. Indeed, in tropospheric aerosol samples TBe is typically found in association with aerosol particles that are 0.3 {micro}m in diameter. Some investigators have asserted that ozone from aloft can be transported into rural and urban regions during stratospheric/tropospheric folding events, leading to increased background levels of ozone. During the Texas 2000 Air Quality study, aerosol samples with a 2.5-{micro}m cutoff were collected during 12-hour cycles (day/night) for a 30-day period at the Deer Park, Texas, field site in August-September 2000. To monitor {sup 7}Be levels, high-volume samples were collected on glass fiber filters on Julian dates 225-259. Sample collection was at a field site near a city park, away from any nearby traffic. This site is under routine operation by the Texas Natural Resource Conservation Commission. Instruments operated at this same site during the study period included an ozone monitor (Dasibi), a nitrogen oxides instrument (API), a CO instrument (API), a nephelometer, a UV-B meter (Richardson-Berger), and a multifilter rotating shadow band radiometer (MFRSR, Yankee Environmental Systems). In addition, we made modified fast-response NO{sub 2} and peroxyacetyl nitrate (PAN) measurements by using a fast gas chromatography with luminol detection, to be described at this meeting (3). The results for {sup 7}Be (mBq m{sup {minus}3})are compared in Figure 1 with the maximum and average ozone values (ppb) observed at the site to identify potential correlations. In Figure 2, all of the {sup 7}Be data are plotted against the maximum and average ozone

  14. 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

  15. Multi-Decadal Variation of Aerosols: Sources, Transport, and Climate Effects

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Bian, Huisheng; Streets, David

    2008-01-01

    We present a global model study of multi-decadal changes of atmospheric aerosols and their climate effects using a global chemistry transport model along with the near-term to longterm data records. We focus on a 27-year time period of satellite era from 1980 to 2006, during which a suite of aerosol data from satellite observations, ground-based measurements, and intensive field experiments have become available. We will use the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model, which involves a time-varying, comprehensive global emission dataset that we put together in our previous investigations and will be improved/extended in this project. This global emission dataset includes emissions of aerosols and their precursors from fuel combustion, biomass burning, volcanic eruptions, and other sources from 1980 to the present. Using the model and satellite data, we will analyze (1) the long-term global and regional aerosol trends and their relationship to the changes of aerosol and precursor emissions from anthropogenic and natural sources, (2) the intercontinental source-receptor relationships controlled by emission, transport pathway, and climate variability.

  16. On the Vertical Distribution of Aerosols and Long-Range Transport Inferred from Calipso Satellite Observations

    NASA Astrophysics Data System (ADS)

    Trepte, Charles; Winker, David; Kittaka, Chieko

    Knowledge on the long-range transport and evolution of aerosols originating from natural and anthropogenic sources is important for understanding their impact on the composition of the atmosphere and the climate system. Over the past several decades a wealth of information on aerosol distributions has been obtained from ground-based instrument networks, dedicated field experiments, and passive remote sensing satellite instruments that has helped to establish the primary aerosol transport pathways over the globe. In many instances, these pathways are broadly reproduced geographically in different chemical-transport models. The models, however, have difficulties at times with accurately projecting the vertical distribution of aerosols, which can lead to significant discrepancies in the lifetimes of the modeled aerosols. This issue is compounded at high latitudes where observations are especially sparse. New measurements from the CALIPSO satellite mission can provide additional insight on the vertical distribution of aerosols over the globe. The mission is a joint effort between the United States (NASA) and France (CNES) and was launched on April 28, 2008 into the A-train satellite constellation. CALIPSO's primary instrument is a two-wavelength polarization-sensitive lidar operating at 532 and 1064 nm with a repetition rate of 20.16 Hz. Lidar observations in the lower troposphere (¡ 8 km) have a vertical resolution of 30 m for the 532 nm channel and 60 m for the 1064 channel. The instrument has been operational since early June 2006. The CALIPSO data set reveals a rich distribution of aerosols in clear and cloudy scenes for both day and night conditions. Information on aerosol type is also available based on their wavelength dependence and polarization characteristics. From these data, a climatology on the vertical and geographic distribution and optical characteristics of aerosols (and clouds) is being developed that can aid diagnostic studies of aerosol transport

  17. Fusion of SeaWiFS and TOMS satellite data with surface observations and topographic data during extreme aerosol events.

    PubMed

    Falke, S R; Husar, R B; Schichtel, B A

    2001-11-01

    Spaceborne sensors allow near-continuous aerosol monitoring throughout the world. This paper illustrates the fusion of Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) and TOMS satellite data with surface observations and topographic data during four extreme aerosol events: (1) the April 1998 Asian dust storm that impacted the west coast of North America, (2) the May 1998 Central American forest fire smoke that impacted eastern North America, (3) the intense fall 1999 northern California fires, and (4) the massive February 2000 Sahara dust storm. During these dust and smoke events, the aerosol was visualized on true color SeaWiFS images as a distinct yellowish dye, the result of the aerosol increasing the reflectance of darker surfaces (ocean and land) and decreasing the reflectance of clouds. TOMS imagery also indicated increased aerosol absorption in the affected areas, while surface monitors measured major reductions in visual range. Fusing these data aids in the determination of the aerosol's spatial, temporal, and optical properties and provides supporting evidence for characterizing what is being visualized as dust or smoke. A 3-dimensional perspective of the events is obtained when incorporating topographic data and provides insight into the vertical properties of the aerosol plumes.

  18. Aerosol variability and atmospheric transport in the Himalayan region from CALIOP 2007-2010 observations

    NASA Astrophysics Data System (ADS)

    Bucci, S.; Cagnazzo, C.; Cairo, F.; Di Liberto, L.; Fierli, F.

    2014-05-01

    This work quantifies the spatial distribution of different aerosol types, their seasonal variability and sources.The analysis of four years of CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization) vertically resolved aerosol data allows the identification of spatial patterns of desert dust and carbonaceous particles in different atmospheric layers. Clusters of Lagrangian back trajectories highlight the transport pathways from source regions during the dusty spring season. The analysis shows a prevalence of dust; at low heights it occurs frequently (up to 70% of available observations) and is distributed north of the Tibetan Plateau with a main contribution from the Gobi and Taklamakan deserts, and west of the Tibetan Plateau, originating from the deserts of southwest Asia and advected by the Westerlies. Above the Himalayas the dust amount is minor but still not negligible (occurrence around 20%) and mainly affected by the transport from more distant deserts sources (Sahara and Arabian Peninsula). Carbonaceous aerosol, produced mainly in northern India and eastern China, is subject to shorter-range transport and is indeed observed closer to the sources, while there is a limited amount reaching the top of the plateau. Data analysis reveals a clear seasonal variability in the frequencies of occurrence for the main aerosol types; dust is regulated principally by the monsoon dynamics, with maximal occurrence in spring. We also highlight relevant interannual differences, showing a larger presence of aerosol in the region during 2007 and 2008. The characterization of the aerosol spatial and temporal distribution in terms of observational frequency is a key piece of information that can be directly used for the evaluation of global aerosol models.

  19. Characterization of aerosol transport in a recoil transfer chamber for heavy element chemistry

    NASA Astrophysics Data System (ADS)

    Lopez Morales, Gabriel; Tereshatov, Evgeny; Folden, Charles

    2014-09-01

    Heavy elements (HE) are elements with Z >103 that can be synthesized via target material bombardment by accelerated charged particles. Production and investigation of properties of new elements result in understanding of upper limit of Periodic Table of Elements. Study of chemical behavior of HE is usually based on comparison with their light homologue properties. Such experiments require transportation of elements of interest from a target chamber to a radiochemical laboratory within several seconds. Aerosol transport is a widely known way to transfer non-volatile elements in on-line experiments. This particular project is devoted to design, characterization and optimization of aerosol transport for implementation in future experiments at Cyclotron Institute, Texas A&M University. Different types of aerosol generators and particle parameters such as: size distribution, concentration and charge have been considered. Results showing procedure development will be presented. *Funded by DOE and NSF-REU Program.

  20. Aerosols and clouds in chemical transport models and climate models.

    SciTech Connect

    Lohmann,U.; Schwartz, S. E.

    2008-03-02

    Clouds exert major influences on both shortwave and longwave radiation as well as on the hydrological cycle. Accurate representation of clouds in climate models is a major unsolved problem because of high sensitivity of radiation and hydrology to cloud properties and processes, incomplete understanding of these processes, and the wide range of length scales over which these processes occur. Small changes in the amount, altitude, physical thickness, and/or microphysical properties of clouds due to human influences can exert changes in Earth's radiation budget that are comparable to the radiative forcing by anthropogenic greenhouse gases, thus either partly offsetting or enhancing the warming due to these gases. Because clouds form on aerosol particles, changes in the amount and/or composition of aerosols affect clouds in a variety of ways. The forcing of the radiation balance due to aerosol-cloud interactions (indirect aerosol effect) has large uncertainties because a variety of important processes are not well understood precluding their accurate representation in models.

  1. Effect of particle settling on lidar profiles of long-range transported Saharan aerosols

    NASA Astrophysics Data System (ADS)

    Gasteiger, Josef; Groß, Silke

    2016-04-01

    A large amount of desert aerosol is transported in the Saharan Air Layer (SAL) westwards from Africa over the Atlantic Ocean. Lidar profiles of transported Saharan aerosol may contain some information about the vertically-resolved aerosol microphysics that could be used to characterize processes that affected the measured aerosol during transport. We present modelled lidar profiles of long-range transported Saharan aerosol assuming that initially the SAL is well-mixed and that there is no vertical mixing of air within the SAL as soon as it reaches the Atlantic. We consider Stokes gravitational settling of aerosol particles over the ocean. The lidar profiles are calculated using optical models for irregularly-shaped mineral dust particles assuming settling-induced particle removal as function of distance from the SAL top. Within the SAL we find a decrease of both the backscatter coefficients and the linear depolarization ratios with decreasing distance from the SAL top. For example, the linear depolarization ratio at a wavelength of 532nm decreases from 0.289 at 1000m to 0.256 at 200m and 0.215 at 100m below SAL top. We compare the modelled backscatter coefficients and linear depolarization ratios to ground-based lidar measurements performed during the SALTRACE field campaign in Barbados (Caribbean) and find agreement within the estimated uncertainties. We discuss the uncertainties of our modeling approach in our presentation. Assumed mineral dust particle shapes, assumed particle mixture properties, and assumptions about processes in the SAL over the continent and the ocean are important aspects to be considered. Uncertainties are relevant for the potential of lidar measurements of transported Saharan dust to learn something about processes occuring in the SAL during long-range transport. We also compare our modeling results to modeling results previously published in the literature.

  2. Influences of natural emission sources (wildfires and Saharan dust) on the urban organic aerosol in Barcelona (Western Mediterranean Basis) during a PM event.

    PubMed

    van Drooge, Barend L; Lopez, Jordi F; Grimalt, Joan O

    2012-11-01

    The urban air quality in Barcelona in the Western Mediterranean Basin is characterized by overall high particulate matter (PM) concentrations, due to intensive local anthropogenic emissions and specific meteorological conditions. Moreover, on several days, especially in summer, natural PM sources, such as long-range transported Saharan dust from Northern Africa or wildfires on the Iberian Peninsula and around the Mediterranean Basin, may influence the levels and composition of the organic aerosol. In the second half of July 2009, daily collected PM(10) filter samples in an urban background site in Barcelona were analyzed on organic tracer compounds representing several emission sources. During this period, an important PM peak event was observed. Individual organic compound concentrations increased two to five times during this event. Although highest increase was observed for the organic tracer of biomass burning, the contribution to the organic aerosol was estimated to be around 6 %. Organic tracers that could be related to Saharan dust showed no correlation with the PM and OC levels, while this was the case for those related to fossil fuel combustion from traffic emissions. Moreover, a change in the meteorological conditions gave way to an overall increase of the urban background contamination. Long-range atmospheric transport of organic compounds from primary emissions sources (i.e., wildfires and Saharan dust) has a relatively moderate impact on the organic aerosol in an urban area where the local emissions are dominating.

  3. Effects on stratospheric ozone from high-speed civil transport: Sensitivity to stratospheric aerosol loading

    NASA Technical Reports Server (NTRS)

    Weisenstein, Debra K.; Ko, Malcolm K. W.; Rodriguez, Jose M.; Sze, Nien-Dak

    1993-01-01

    The potential impact of high-speed civil transport (HSCT) aircraft emissions on stratospheric ozone and the sensitivity of these results to changes in aerosol loading are examined with a two-dimensional model. With aerosols fixed at background levels, calculated ozone changes due to HSCT aircraft emissions range from negligible up to 4-6% depletions in column zone at northern high latitudes. The magnitude of the ozone change depends mainly on the NO(x) increase due to aircraft emissions, which depends on fleet size, cruise altitude, and engine design. The partitioning of the odd nitrogen species in the lower stratosphere among NO, NO2, N2O5, is strongly dependent on the concentration of sulfuric acid aerosol particles, and thus the sensitivity of O3 to NO(x) emissions changes when the stratospheric aerosol loading changes. Aerosol concentrations 4 times greater than background levels have not been unusual in the last 2 decades. Our model results show that a factor of 4 increase in aerosol loading would significantly reduce the calculated ozone depletion due to HSCT emissions. Because of the neutral variabiltiy of stratospheric aerosols, the possible impact of HSCT emissions on ozone must be viewed as a range of possible results.

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

    SciTech Connect

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

    1986-06-01

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

  5. Projected effect of 2000-2050 changes in climate and emissions on aerosol levels in China and associated transboundary transport

    EPA Science Inventory

    We investigate projected 2000–2050 changes in concentrations of aerosols in China and the associated transboundary aerosol transport by using the chemical transport model GEOS-Chem driven by the Goddard Institute for Space Studies (GISS) general circulation model (GCM) 3 at 4° × ...

  6. The global impact of the transport sectors on atmospheric aerosol in 2030 - Part 2: Aviation

    NASA Astrophysics Data System (ADS)

    Righi, Mattia; Hendricks, Johannes; Sausen, Robert

    2016-04-01

    We use the EMAC (ECHAM/MESSy Atmospheric Chemistry) global climate-chemistry model coupled to the aerosol module MADE (Modal Aerosol Dynamics model for Europe, adapted for global applications) to simulate the impact of aviation emissions on global atmospheric aerosol and climate in 2030. Emissions of short-lived gas and aerosol species follow the four Representative Concentration Pathways (RCPs) designed in support of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We compare our findings with the results of a previous study with the same model configuration focusing on year 2000 emissions. We also characterize the aviation results in the context of the other transport sectors presented in a companion paper. In spite of a relevant increase in aviation traffic volume and resulting emissions of aerosol (black carbon) and aerosol precursor species (nitrogen oxides and sulfur dioxide), the aviation effect on particle mass concentration in 2030 remains quite negligible (on the order of a few ng m-3), about 1 order of magnitude less than the increase in concentration due to other emission sources. Due to the relatively small size of the aviation-induced aerosol, however, the increase in particle number concentration is significant in all scenarios (about 1000 cm-3), mostly affecting the northern mid-latitudes at typical flight altitudes (7-12 km). This largely contributes to the overall change in particle number concentration between 2000 and 2030, which also results in significant climate effects due to aerosol-cloud interactions. Aviation is the only transport sector for which a larger impact on the Earth's radiation budget is simulated in the future: the aviation-induced radiative forcing in 2030 is more than doubled with respect to the year 2000 value of -15 mW m-2 in all scenarios, with a maximum value of -63 mW m-2 simulated for RCP2.6.

  7. 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.

  8. Modelling multi-component aerosol transport problems by the efficient splitting characteristic method

    NASA Astrophysics Data System (ADS)

    Liang, Dong; Fu, Kai; Wang, Wenqia

    2016-11-01

    In this paper, a splitting characteristic method is developed for solving general multi-component aerosol transports in atmosphere, which can efficiently compute the aerosol transports by using large time step sizes. The proposed characteristic finite difference method (C-FDM) can solve the multi-component aerosol distributions in high dimensional domains over large ranges of concentrations and for different aerosol types. The C-FDM is first tested to compute the moving of a Gaussian concentration hump. Comparing with the Runge-Kutta method (RKM), our C-FDM can use very large time step sizes. Using Δt = 0.1, the accuracy of our C-FDM is 10-4, but the RKM only gets the accuracy of 10-2 using a small Δt = 0.01 and the accuracy of 10-3 even using a much smaller Δt = 0.002. A simulation of sulfate transport in a varying wind field is then carried out by the splitting C-FDM, where the sulfate pollution is numerically showed expanding along the wind direction and the effects of the different time step sizes and different wind speeds are analyzed. Further, a realistic multi-component aerosol transport over an area in northeastern United States is studied. Concentrations of PM2.5 sulfate, ammonium, nitrate are high in the urban area, and low in the marine area, while sea salts of sodium and chloride mainly exist in the marine area. The normalized mean bias and the normalized mean error of the predicted PM2.5 concentrations are -6.5% and 24.1% compared to the observed data measured at monitor stations. The time series of numerical aerosol concentration distribution show that the strong winds can move the aerosol concentration peaks horizontally for a long distance, such as from the urban area to the rural area and from the marine area to the urban and rural area. Moreover, we also show the numerical time duration patterns of the aerosol concentration distributions due to the affections of the turbulence and the deposition removal. The developed splitting C-FDM algorithm

  9. Seasonal contrast in aerosol abundance over northern south Asia using a chemical transport model

    NASA Astrophysics Data System (ADS)

    Venkataraman, C.; Sadavarte, P.; Madhavan, B. L.; Kulkarni, S.; Carmichael, G. R.; Adhikary, B.; D'Allura, A.; Cherian, R.; Das, S.; Gupta, T.; Streets, D. G.; Wei, C.; Zhang, Q.

    2012-12-01

    Northern South-Asia, home to about half a billion people, experiences large aerosol abundances almost all year around. There are gaps in our understanding of seasonal variations in regional aerosol emissions, abundance and radiative effects. The present study uses chemical transport model simulations (at ~ 60km resolution), with regionally estimated emissions, to investigate the contrast in aerosol surface and columnar abundance during pre-monsoon transition, monsoon and inter-monsoon transition periods over than Gangetic plain (GP) and Tibetan plateau. The interplay between aerosol emissions and atmospheric transport is examined to explain the variability. Model predictions were evaluated with available in-situ measurements and AOD from AERONET and MODIS level-2 retrievals (at 10 km resolution) processed with quality weighting to the model resolution. During April, AOD was dominated by dust at most sites across the GP and Tibet. However, AOD from organic carbon (emitted from agricultural residue burning) is also significant at several sites (Pantnagar, Godavari, Kolkata, Dhaka, and at high altitude Pyramid and Lhasa sites), consistent with recently reported MISR climatology in this region. In contrast, during July and September, AOD was dominated by sulfate at all sites. In April, aerosols over the GP could be attributed to emissions from large industrial sources (thermal power plant, cement industries, iron & steel and other industries) and agricultural residue burning transported from the northwest, along with forest burning emissions transported from the east. Large fluxes of open burning emissions in the east GP, along with prevailing easterly wind flow into the GP led to an east-west gradient in anthropogenic aerosols. During July, there was little open burning, so aerosol concentrations were largely from industrial emissions transported out through the north. In the Tibet region, dust was predominant during both April and July. During September

  10. Morphological and elemental properties of urban aerosols among PM events and different traffic systems.

    PubMed

    Maskey, Shila; Chae, Hoseung; Lee, Kwangyul; Dan, Nguyen Phuoc; Khoi, Tran Tien; Park, Kihong

    2016-11-01

    Morphology and elemental composition of individual fine ambient particles varied among types of PM events and between two different urban environments having different major transportation systems (gasoline/diesel vehicles versus motorcycles). Carbonaceous particles were the most dominant in PM events, whereas S-rich particles were the highest in non-events at urban Gwangju in Korea. The aged soot, semi-volatile organic (SVO), and non-volatile organic (NVO) particles were more abundant in the polluted-long range transport (LTP) event than those in the dust-LTP event and non-event. In the dust-LTP event, the aged mineral dust particles outnumbered the fresh ones, suggesting the mineral dust particles were aged during their long-range transport. At HoChiMinh (HCM) in Vietnam, the fraction of carbonaceous particles was much higher than Gwangju (66% versus 30%) possibly due to more abundant two-stroke motor vehicles at HCM. Of the carbonaceous particles, combustion soot (19%) was the highest, followed by NVO (18%), SVO (17%), and biological particles (11%) at HCM, whereas SVO (11%) and NVO (10%) particles were the highest, followed by combustion soot particles (8%) at Gwangju. The higher fraction of mineral dust particles was also observed at HCM, indicating the sampling site was influenced by dust from unpaved roads and construction sites. PMID:27262278

  11. Atmospheric Transport of Arid Aerosol from Desert Regions of Central Asia

    NASA Astrophysics Data System (ADS)

    Chen, Boris; Solomon, Paul; Sitnov, Sergei; Grechko, Evgeny; Maximenkov, Leonid; Artamonova, Maria; Pogarski, Fedor

    2010-05-01

    Investigation of atmospheric transport of arid aerosol from Central Asia was held within the ISTC project 3715. Particular attention was paid to the removal of aerosol from the Aral Sea region and its further transport, because aerosol and pollutants emission from Central Asia affect the airspace of the entire Asian continent. At the same time measurements of aerosols in the atmosphere of Central Asia are holding in a small number of stations, and currently available data are insufficient to define the initial conditions and/or verification of models of long-range transport. To identify sources of pollution transported from Central Asia, in Kyrgyzstan measurement and sampling of air were organized: at the station on the northern slope of the Kirgiz Range, 30 km south of Bishkek, at an altitude of 1700 m above sea level (Bishkek Site, 42,683N; 74,694E ), and on permanent alpine Teploklyuchenka lidar station in the Central Tien Shan at an altitude of 2000 m above sea level (Lidar Site, 42,467N; 78,533E). The chemical analysis of collected aerosol and soils samples was carried out. Measurements of aerosol at these stations have been merged with the simulation of the trajectories of air masses in the study region and with the satellite (the Terra and Aqua satellites) observations of aerosol optical thickness in this region. Satellite data for the region 43-47 N, and 58-62 E (Aral Sea) from April 2008 to September 2009 were analyzed. The moments were selected, when the value of aerosol optical thickness (AOT) was greatest (more than 0.5), and the transport from the Aral Sea region to the observation sites took place. For each of these days, the forward trajectories, which started at 6 points within the region, were calculated using the HYSPLIT model. The days, on which the trajectories reached the BISHKEK and LIDAR sites, were determined from the data obtained. Calculations on the basis of the RAMS model were performed for these days. These calculations were performed

  12. Intercomparison of observations and model aerosol parameters during two Saharan dust events over the southern United Kingdom

    NASA Astrophysics Data System (ADS)

    Buxmann, Joelle; Adam, Mariana; Ordonez, Carlos; Tilbee, Marie; Smyth, Tim; Claxton, Bernard; Sugier, Jacqueline; Agnew, Paul

    2015-04-01

    Saharan desert dust lifted by convection over the hot desert surface can reach high altitudes and be transported over great distances. In the UK, Saharan dust episodes occur several times a year, usually during the spring. Dust lifted by cyclonic circulation is often blown into the Atlantic and transported to the UK. This can result in a rapid degradation of air quality due to the increase in the levels of particulate matter (PM). The ability to model the transport and deposition of dust remains an important challenge in order to characterize different pollution events. We present a comparison of observed Aerosol Optical Depth (AOD) with modelled AOD from the Met Office Air Quality Unified Model (AQUM), performed for two dust events in March 2014 (at 380nm, 440nm, 870nm and 1020nm). The observations are derived from five sun photometers located in the southern UK at Exeter, Cardington, Bayfordbury, Chilbolton, and Plymouth. Correlations are investigated between model column integrated PM2.5 and PM10, and observed fine and coarse mode AOD from AERONET. Vertical profiles of attenuated backscatter and extinction from the Jenoptik Nimbus ceilometers part of the Met Office Laser Cloud Base Recorder (LCBR) network are investigated as well (see also session AS3.17/GI2.2 Lidar and Applications). The Met Office air quality model AQUM is an on-line meteorology, chemistry and aerosol modelling system. It runs at a resolution of 12km over a domain covering the UK and north-western Europe. Atmospheric composition modelling employs two-way coupling between aerosol and chemistry evolution, with explicit modelling of sulphate, nitrate, black carbon, organic carbon, biomass burning and wind-blown mineral dust aerosol components. Both the model and observations show an increase in AOD during the first period from 12 -13 March 2014. For example AOD levels of up to 0.52 for the 380nm channel were recorded by the sun photometer in Exeter. This is relatively high compared to average

  13. A Model for the Transport of Sea-Spray Aerosols in the Coastal Zone

    NASA Astrophysics Data System (ADS)

    Piazzola, J.; Tedeschi, G.; Demoisson, A.

    2015-05-01

    We study the dynamics of sea-spray particles in the coastal region of La Reunion Island on the basis of numerical simulations using the transport aerosol model MACMod (Marine Aerosol Concentration Model) and a survey of the aerosol size distributions measured at four locations at two different heights in the north-west part of the island. This allows evaluation of the performance of our model in case of pure marine air masses with implementation of accurate boundary conditions. First of all, an estimate of the aerosol concentration at 10-m height at the upwind boundary of the calculation domain is obtained using a revisited version of the MEDEX (Mediterranean Extinction) model. Estimates of the vertical profile of aerosol concentrations are then provided using aerosol data obtained at two different heights at the upwind boundary of the calculation domain. A parametrization of the vertical profiles of aerosol concentrations for maritime environment is proposed. The results are then compared to the vertical profiles of 0.532 m aerosol particle extinction coefficient obtained from lidar data provided by the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) and also to the data provided by the Aerosol Robotic Network (AERONET). This allows validation of the complete vertical profiles in the mixed layer and shows the validity of satellite data for determination of the vertical profiles. Two kinds of simulation were made: one without a particle advection flux at the upwind boundary of the numerical domain, whereas the second simulation was made with a particle advection flux. In the first case, the influence of the distance to the shoreline on the local sea-spray dynamics is investigated. In the second set of simulation, the particles issued from the local production in the surf zone near the shoreline are mixed with aerosols advected from the remote ocean. A good agreement between the model calculations using our boundary conditions and the data was found. The

  14. Simulation of the recent evolution of stratospheric aerosols by the MOSTRA Simulation of the recent evolution of stratospheric aerosols by the MOSTRA microphysical/transport model

    NASA Astrophysics Data System (ADS)

    Bingen, Christine; Errera, Quentin; Vanhellemont, Filip; Fussen, Didier; Mateshvili, Nina; Dekemper, Emmanuel; Loodts, Nicolas

    2010-05-01

    We present recent advances in the development of a microphysical/transport model for stratospheric aerosols, called MOdel for STRatospheric Aerosols (MOSTRA). MOSTRA is a 3D model describing the evolution in time and space of the stratospheric aerosol distribution described using a set of discrete size bins. The microphysical module used in this model makes use of the PSCBOX model developed by Larsen (2000). The transport module is based on the flux-form semi-Lagragian scheme by Lin and Rood (1996). The model structure will be presented with simulations of the evolution of the volcanic aerosol plume after recent volcanic eruptions. References: N. Larsen, Polar Stratospheric Clouds, Microphysical and optical models, Scientific Report 00-06, Danish Meteorological Institute, 2000 Lin, S.-J. Rood, R.B., Multidimensional Flux-Form Semi-Lagrangian Transport Schemes, Monthly Weather Review, 124, 2046-2070, 1996.

  15. Investigation of biomass burning and aerosol loading and transport in South America utilizing geostationary satellites

    NASA Technical Reports Server (NTRS)

    Menzel, Paul; Prins, Elaine

    1995-01-01

    This study attempts to assess the extent of burning and associated aerosol transport regimes in South America and the South Atlantic using geostationary satellite observations, in order to explore the possible roles of biomass burning in climate change and more directly in atmospheric chemistry and radiative transfer processes. Modeling and analysis efforts have suggested that the direct and indirect radiative effects of aerosols from biomass burning may play a major role in the radiative balance of the earth and are an important factor in climate change calculations. One of the most active regions of biomass burning is located in South America, associated with deforestation in the selva (forest), grassland management, and other agricultural practices. As part of the NASA Aerosol Interdisciplinary Program, we are utilizing GOES-7 (1988) and GOES-8 (1995) visible and multispectral infrared data (4, 11, and 12 microns) to document daily biomass burning activity in South America and to distinguish smoke/aerosols from other multi-level clouds and low-level moisture. This study catalogues the areal extent and transport of smoke/aerosols throughout the region and over the Atlantic Ocean for the 1988 (July-September) and 1995 (June-October) biomass burning seasons. The smoke/haze cover estimates are compared to the locations of fires to determine the source and verify the haze is actually associated with biomass burning activities. The temporal resolution of the GOES data (half-hourly in South America) makes it possible to determine the prevailing circulation and transport of aerosols by considering a series of visible and infrared images and tracking the motion of smoke, haze and adjacent clouds. The study area extends from 40 to 70 deg W and 0 to 40 deg S with aerosol coverage extending over the Atlantic Ocean when necessary. Fire activity is estimated with the GOES Automated Biomass Burning Algorithm (ABBA). To date, our efforts have focused on GOES-7 and GOES-8 ABBA

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    Smoke aerosols from biomass burning are an important component of the global aerosol cycle. Analysis of Aerosol Robotic Network (AERONET) retrievals of size distribution and refractive index reveals variety between biomass burning aerosols in different global source regions, in terms of aerosol particle size and single scatter albedo (SSA). Case studies of smoke transported to coastal/island AERONET sites also mostly lie within the range of variability at near-source sites. Two broad ''families'' of aerosol properties are found, corresponding to sites dominated by boreal forest burning (larger, broader fine mode, with midvisible SSA ∼0.95), and those influenced by grass, shrub, or crop burning with additional forest contributions (smaller, narrower particles with SSA ∼0.88-0.9 in the midvisible). The strongest absorption is seen in southern African savannah at Mongu (Zambia), with average SSA ∼0.85 in the midvisible. These can serve as candidate sets of aerosol microphysical/optical properties for use in satellite aerosol optical depth (AOD) retrieval algorithms. The models presently adopted by these algorithms over ocean are often insufficiently absorbing to represent these biomass burning aerosols. A corollary of this is an underestimate of AOD in smoke outflow regions, which has important consequences for applications of these satellite datasets.

  17. Aeronet-based Microphysical and Optical Properties of Smoke-dominated Aerosol near Source Regions and Transported over Oceans, and Implications for Satellite Retrievals of Aerosol Optical Depth

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    Smoke aerosols from biomass burning are an important component of the global aerosol cycle. Analysis of Aerosol Robotic Network (AERONET) retrievals of size distribution and refractive index reveals variety between biomass burning aerosols in different global source regions, in terms of aerosol particle size and single scatter albedo (SSA). Case studies of smoke transported to coastal/island AERONET sites also mostly lie within the range of variability at near-source sites. Two broad families of aerosol properties are found, corresponding to sites dominated by boreal forest burning (larger, broader fine mode, with midvisible SSA 0.95), and those influenced by grass, shrub, or crop burning with additional forest contributions (smaller, narrower particles with SSA 0.88-0.9 in the midvisible). The strongest absorption is seen in southern African savanna at Mongu (Zambia), with average SSA 0.85 in the midvisible. These can serve as candidate sets of aerosol microphysicaloptical properties for use in satellite aerosol optical depth (AOD) retrieval algorithms. The models presently adopted by these algorithms over ocean are often insufficiently absorbing to represent these biomass burning aerosols. A corollary of this is an underestimate of AOD in smoke outflow regions, which has important consequences for applications of these satellite datasets.

  18. Aerosol transport over Siberia: analysis of the summer 2013 YAK-AEROSIB aircraft campaign

    NASA Astrophysics Data System (ADS)

    Ancellet, Gerard; Penner, Johannes; Kokhanenko, Grigorii; Arshinov, Mikhail; Chernov, Dimitry; Kozlov, Valery; Paris, Jean Daniel; Pruvost, Arnaud; Belan, Boris; Nedelec, Philippe; Pelon, Jacques; Law, Kathy

    2014-05-01

    Transport and transformation of aerosols related to forest fires and Eastern Asia anthropogenic emissions have been identified as very important questions to understand the Arctic climate. Two aircraft campaigns have been conducted over Siberia in summer 2012 and 2013 with in-situ measurements by aerosol spectrometers and also by a 532 nm backscatter lidar in 2013. The aerosol data can be also combined with CO measurements measured on-board the aircraft to identify the aerosol pollution sources. The analysis of the transport processes has been performed with the FLEXPART Lagrangian model run either in the forward or backward mode. While the 2012 campaign is characterized by anticyclonic conditions and strong forest fire emissions, the 2013 campaign corresponds to upward lifting of Northern China emissions. Comparisons with satellite data obtained with the CALIPSO mission for the two summer periods will be presented to identify the spatial extent and the temporal evolution of the pollution plumes and also to test the ability of the satellite data to derive the aerosol types. This work was funded by CNRS (France), the French Ministry of Foreign Affairs, CEA (France), 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 14-05-00526, 14-05-00590).

  19. Aerosol-radiation-cloud and precipitation processes during dust events (Invited)

    NASA Astrophysics Data System (ADS)

    Kallos, G. B.; Solomos, S.; Kushta, J.; Mitsakou, C.; Athanasiadis, P.; Spyrou, C.; Tremback, C.

    2010-12-01

    describe. Some of these properties will be discussed during the presentation. In this presentation, model results concerning the impact of dust, sea salt and anthropogenic pollutants on radiative transfer clouds and precipitation will be discussed. Typical cases of such processes have been selected and analyzed in the Euro-Mediterranean region and East Atlantic where the mixture of anthropogenic with natural aerosols define the major characteristics of the weather events associated with the water budget to a certain degree. As it was found, extreme weather events such as heavy storms in the Eastern Mediterranean or deep convective systems in the East-Central Atlantic are affected by the aerosol size and chemical composition (e.g. pure dust or dust coated by sulfates or sea salt).The position, local maxima and precipitation amounts may vary significantly according to the CCN and IN generation mechanism. Connections and implications between aerosol characteristics and precipitation distribution and amounts are discussed in general. Finally the impacts of Saharan dust on the short and long-wave radiation budget of the area are discussed. The model results are compared with in situ measurements as well as satellite observations.

  20. Uncertainty in Cloud Aerosol Transport System (CATS) Doppler Lidar Products and Measurements

    NASA Astrophysics Data System (ADS)

    Selmer, P. A.

    2010-12-01

    The Cloud Aerosol Transport System (CATS) is both a high spectral resolution lidar and Doppler lidar currently being developed at NASA Goddard Space Flight Center for use as a demonstrator instrument for NASA’s Aerosol Cloud Ecosystem (ACE) Mission. CATS is intended to fly on NASA’s high-altitude ER-2 aircraft. CATS will be capable of measuring both aerosol properties and horizontal wind velocity as a function of altitude. The accuracy of these measurements is important to the success of the instrument and the ACE mission. Uncertainty equations for both the aerosol and wind products are derived. Initially the only sources of error are assumed to be instrument error in the spectral measurements. Using simulated CATS spectral measurements from simulated atmospheric profiles (an atmosphere with only a cirrus layer, an atmosphere with only a cumulus layer, an atmosphere with only an aerosol layer, and an atmosphere with no clouds or aerosols), the uncertainty in the aerosol and wind products are calculated. These calculated uncertainties are found to be within reason. Also worthy of consideration is the effect of aircraft motion on CATS’ wind measurements and products. An equation for the the nadir angle (assumed to be about 45 degrees for CATS), as well as the uncertainty in this angle, in terms of aircraft pitch and roll is derived. The effect of uncertainty in this angle on the uncertainty in CATS aerosol and wind products is calculated using the same simulated data previously mentioned, which is found to be insignificant for normal, steady flight.

  1. [Microphysics of atmospheric aerosols during winter haze/fog events in Nanjing].

    PubMed

    Yang, Jun; Niu, Zhong-qing; Shi, Chun-e; Liu, Duan-yang; Li, Zi-hua

    2010-07-01

    Intensive field observations of fog/haze events, including simultaneous measurements of aerosol particle and fog droplet size distributions, were conducted in Nanjing in November, 2007. Four weather conditions (fog, mist, wet haze and haze) were distinguished based on visibility and liquid water content firstly. Then, the microphysical characteristics of coarse and fine particles in each condition were investigated. The results showed the dominant sequence of the four weather conditions was haze<-->mist-->wet haze-->fog-->, wet haze-->mist<-->haze. The lasting time of pre-fog wet haze was longer than that of post-fog wet haze. The number, surface area and volume concentration of coarse particles with diameter larger than 2.0 micron in fog were much higher than those in the other three conditions, and the smallest concentrations were observed in haze. The size distributions of surface area and volume concentration exhibited multi-peak in fog droplets, while it showed single peak for coarse particles in haze, mist and wet haze. For the fine particles with diameter larger than 0.010 microm, the spectral shapes of surface area concentration are similar in fog (mist) and wet haze (haze) condition. The dominant size ranges of fine particle number concentration were in 0.04-0.13 microm and 0.02-0.14 microm for fog and wet haze, separately. The same dominant size ranges located in 0.02-0.06 microm for both mist and haze. During the transition processes from haze, mist and wet haze to fog, the concentration of smaller particles (less than 0.060-0.090 microm) reduced and vice versa for the corresponding larger particles. Temporal variation of aerosol number concentration correlated well with the root mean diameters negatively during the observation period. The number concentration of aerosol was the lowest and the mean diameter was the largest in fog periods.

  2. Aerosol variability and atmospheric transport in the Himalayan region from CALIOP 2007-2010 observations

    NASA Astrophysics Data System (ADS)

    Bucci, S.; Cagnazzo, C.; Cairo, F.; Di Liberto, L.; Fierli, F.

    2013-06-01

    Himalayan Plateau is surrounded by regions with high natural and anthropogenic aerosol emissions that have a strong impact on regional climate. This is particularly critical for the Himalayan glaciers whose equilibrium is also largely influenced by radiative direct and indirect effects induced by aerosol burden. This work focuses on the spatial and vertical distribution of different aerosol types, their seasonal variability and sources. The analysis of the 2007-2010 yr of CALIPSO vertically resolved satellite data allows the identification of spatial patterns of desert dust and carbonaceous particles in different atmospheric layers. Clusters of Lagrangian back-trajectories highlight the transport pathways from source regions during the dusty spring season. The analysis shows a prevalence of dust; at low heights they are distributed mainly north (with a main contribution from the Gobi and Taklamakan deserts) and west of the Tibetan Plateau (originating from the deserts of South-West Asia and advected by the westerlies). Above the Himalayas the dust amount is minor but still not negligible (detectable in around 20% of the measurements), and transport from more distant deserts (Sahara and Arabian Peninsula) is important. Smoke aerosol, produced mainly in North India and East China, is subject to shorter range transport and is indeed observed closer to the sources while there is a limited amount reaching the top of the plateau. Data analysis reveals a clear seasonal variability in the frequencies of occurrence for the main aerosol types; dust is regulated principally by the monsoon dynamics, with maxima of occurrence in spring. The study also highlights relevant interannual differences, showing a larger presence of aerosol in the region during 2007 and 2008 yr.

  3. Occupational exposure to aerosolized brevetoxins during Florida red tide events: effects on a healthy worker population.

    PubMed

    Backer, Lorraine C; Kirkpatrick, Barbara; Fleming, Lora E; Cheng, Yung Sung; Pierce, Richard; Bean, Judy A; Clark, Richard; Johnson, David; Wanner, Adam; Tamer, Robert; Zhou, Yue; Baden, Daniel G

    2005-05-01

    Karenia brevis (formerly Gymnodinium breve) is a marine dinoflagellate responsible for red tides that form in the Gulf of Mexico. K. brevis produces brevetoxins, the potent toxins that cause neurotoxic shellfish poisoning. There is also limited information describing human health effects from environmental exposures to brevetoxins. Our objective was to examine the impact of inhaling aerosolized brevetoxins during red tide events on self-reported symptoms and pulmonary function. We recruited a group of 28 healthy lifeguards who are occupationally exposed to red tide toxins during their daily work-related activities. They performed spirometry tests and reported symptoms before and after their 8-hr shifts during a time when there was no red tide (unexposed period) and again when there was a red tide (exposed period). We also examined how mild exercise affected the reported symptoms and spirometry tests during unexposed and exposed periods with a subgroup of the same lifeguards. Environmental sampling (K. brevis cell concentrations in seawater and brevetoxin concentrations in seawater and air) was used to confirm unexposed/exposed status. Compared with unexposed periods, the group of lifeguards reported more upper respiratory symptoms during the exposed periods. We did not observe any impact of exposure to aerosolized brevetoxins, with or without mild exercise, on pulmonary function.

  4. Physical characterization of aerosol particles during the Chinese New Year’s firework events

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Wang, Xuemei; Chen, Jianmin; Cheng, Tiantao; Wang, Tao; Yang, Xin; Gong, Youguo; Geng, Fuhai; Chen, Changhong

    2010-12-01

    Measurements for particles 10 nm to 10 μm were taken using a Wide-range Particle Spectrometer during the Chinese New Year (CNY) celebrations in 2009 in Shanghai, China. These celebrations provided an opportunity to study the number concentration and size distribution of particles in an especial atmospheric pollution situation due to firework displays. The firework activities had a clear contribution to the number concentration of small accumulation mode particles (100-500 nm) and PM 1 mass concentration, with a maximum total number concentration of 3.8 × 10 4 cm -3. A clear shift of particles from nucleation and Aitken mode to small accumulation mode was observed at the peak of the CNY firework event, which can be explained by reduced atmospheric lifetimes of smaller particles via the concept of the coagulation sink. High particle density (2.7 g cm -3) was identified as being particularly characteristic of the firework aerosols. Recalculated fine particles PM 1 exhibited on average above 150 μg m -3 for more than 12 hours, which was a health risk to susceptible individuals. Integral physical parameters of firework aerosols were calculated for understanding their physical properties and further model simulation.

  5. Quiescence of Asian dust events in South Korea and Japan during 2012 spring: Dust outbreaks and transports

    NASA Astrophysics Data System (ADS)

    Lee, Yun Gon; Ho, Chang-Hoi; Kim, Joo-Hong; Kim, Jhoon

    2015-08-01

    This study examined the quiescence of Asian dust events in South Korea and Japan during the spring of 2012, presenting a synoptic characterization and suggesting possible causes. Synoptic observation reports from the two countries confirmed that spring 2012 had the lowest number of dust events in 2000-2012. The monthly dust frequency (DF) in March 2012 over the dust source regions, i.e., deserts in northern China and Mongolia, indicated a significant decrease compared to the 12 year (2000-2011) March climatology. The DF in April 2012 was comparable to the 12 year climatology values, but in May 2012 it was slightly lower. The daily Ozone Monitoring Instrument Aerosol Index and the Navy Aerosol Analysis and Prediction System simulations revealed stagnant dust movement in March and May 2012. Anomalous anticyclones north of the source regions decreased the dust outbreaks and enhanced the southeasterly winds, resulting in few dust events over the downwind countries (i.e., South Korea and Japan). By contrast, in April 2012, a strong anomalous cyclone east of Lake Baikal slightly increased the dust outbreaks over northeastern China. However, the major dust outbreaks were not transported downwind because of exceptional dust pathways, i.e., the southeastward pathway of dust transport was unusually blocked by the expansion of an anomalous anticyclonic circulation over the Sea of Okhotsk, with dust being transported northeast.

  6. Aerosol advection and sea salt events in Genoa, Italy, during the second half of 2005.

    PubMed

    Marenco, Franco; Mazzei, Federico; Prati, Paolo; Gatti, Massimiliano

    2007-05-15

    Atmospheric aerosols in the PM(10) fraction have been simultaneously sampled at three sites in the Genoa urban and suburban area during the second half of 2005, and information on the elemental composition has been gathered through energy dispersive X-ray fluorescence. Thanks to the simultaneous measurements and wind information, a few aerosol transport and transformation processes originated from the nearby sea and in the neighbouring Po Valley have been described. Sea salt concentrations at the three sites were well correlated and often related to Southern sector winds; moreover, by examining the Cl/Na ratio at two sites the time scale for Cl depletion in particulate matter has been estimated as 1-1.5 h for the Genoa atmosphere. During a Northerly gale, excess elemental Si concentrations (peaking more than 4 mug m(-3)) were found at two sites, and were ascribed to an unknown local source. Finally, during an 11-day long 'heat wave' large concentrations for total PM(10), dust and secondary compounds have been found; these large concentrations lead to a number of exceedances of air quality standards, and have been ascribed to advection from the Po Valley.

  7. Influence of atmospheric parameters on vertical profiles and horizontal transport of aerosols generated in the surf zone

    NASA Astrophysics Data System (ADS)

    Kusmierczyk-Michulec, J.; Tedeschi, G.; Van Eijk, A. M. J.; Piazzola, J.

    2013-10-01

    The vertical and horizontal transport of aerosols generated over the surf zone is discussed. Experimental data were collected during the second campaign of the Surf Zone Aerosol Experiment that took place in Duck NC (USA) in November 2007. The Empirical Orthogonal Function (EOF) method was used to analyze the vertical concentration gradients, and allowed separating the surf aerosols from aerosols advected from elsewhere. The numerical Marine Aerosol Concentration Model (MACMod) supported the analysis by confirming that the concentration gradients are more pronounced under stable conditions and that aerosol plumes are then more confined to the surface. The model also confirmed the experimental observations made during two boat runs along the offshore wind vector that surf-generated aerosols are efficiently advected out to sea over several tens of kilometers.

  8. Final Report: Safety of Plasma Components and Aerosol Transport During Hard Disruptions and Accidental Energy Release in Fusion Reactor

    SciTech Connect

    Bourham, Mohamed A.; Gilligan, John G.

    1999-08-14

    Safety considerations in large future fusion reactors like ITER are important before licensing the reactor. Several scenarios are considered hazardous, which include safety of plasma-facing components during hard disruptions, high heat fluxes and thermal stresses during normal operation, accidental energy release, and aerosol formation and transport. Disruption events, in large tokamaks like ITER, are expected to produce local heat fluxes on plasma-facing components, which may exceed 100 GW/m{sup 2} over a period of about 0.1 ms. As a result, the surface temperature dramatically increases, which results in surface melting and vaporization, and produces thermal stresses and surface erosion. Plasma-facing components safety issues extends to cover a wide range of possible scenarios, including disruption severity and the impact of plasma-facing components on disruption parameters, accidental energy release and short/long term LOCA's, and formation of airborne particles by convective current transport during a LOVA (water/air ingress disruption) accident scenario. Study, and evaluation of, disruption-induced aerosol generation and mobilization is essential to characterize database on particulate formation and distribution for large future fusion tokamak reactor like ITER. In order to provide database relevant to ITER, the SIRENS electrothermal plasma facility at NCSU has been modified to closely simulate heat fluxes expected in ITER.

  9. Chemistry and processes of aerosols at Mt. Bachelor, a high elevation site in the Pacific Northwest U.S.: influences from regional transport and wildfire plumes

    NASA Astrophysics Data System (ADS)

    Collier, S.; Zhou, S.; Hee, J.; Jaffe, D. A.; Wigder, N. L.; Zhang, Q.

    2013-12-01

    . Observations during the affected periods show elevated organic PM1 loading of up to 60 μg/m3 and an overall organic mass fraction of 90% while correlating with elevated aerosol light scattering and gas-phase CO concentration. OA from these events have shown an enhancement in the BB characteristic ion (C2H4O2+) at m/z = 60 and with O/C ranging from 0.4-0.6, suggesting these BB aerosols are intermediately oxidized. Inorganic nitrates and amines also appear to be important components of these detected BB events. More detailed analyses, such as back-trajectory analysis and factor analysis of the HR-ToF-AMS spectra, will be performed to unravel the significance of these sampled events and how the transport affects fresh BB plumes. These analyses may also shed light on the importance of BB emissions as precursors to secondary organic aerosol and their overall effect on regional air quality in the Pacific Northwest.

  10. High resolution simulations of aerosol microphysics in a global and regionally nested chemical transport model

    NASA Astrophysics Data System (ADS)

    Adams, P. J.; Marks, M.

    2015-12-01

    The aerosol indirect effect is the largest source of forcing uncertainty in current climate models. This effect arises from the influence of aerosols on the reflective properties and lifetimes of clouds, and its magnitude depends on how many particles can serve as cloud droplet formation sites. Assessing levels of this subset of particles (cloud condensation nuclei, or CCN) requires knowledge of aerosol levels and their global distribution, size distributions, and composition. A key tool necessary to advance our understanding of CCN is the use of global aerosol microphysical models, which simulate the processes that control aerosol size distributions: nucleation, condensation/evaporation, and coagulation. Previous studies have found important differences in CO (Chen, D. et al., 2009) and ozone (Jang, J., 1995) modeled at different spatial resolutions, and it is reasonable to believe that short-lived, spatially-variable aerosol species will be similarly - or more - susceptible to model resolution effects. The goal of this study is to determine how CCN levels and spatial distributions change as simulations are run at higher spatial resolution - specifically, to evaluate how sensitive the model is to grid size, and how this affects comparisons against observations. Higher resolution simulations are necessary supports for model/measurement synergy. Simulations were performed using the global chemical transport model GEOS-Chem (v9-02). The years 2008 and 2009 were simulated at 4ox5o and 2ox2.5o globally and at 0.5ox0.667o over Europe and North America. Results were evaluated against surface-based particle size distribution measurements from the European Supersites for Atmospheric Aerosol Research project. The fine-resolution model simulates more spatial and temporal variability in ultrafine levels, and better resolves topography. Results suggest that the coarse model predicts systematically lower ultrafine levels than does the fine-resolution model. Significant

  11. Aerosol optical and physical properties during winter monsoon pollution transport in an urban environment.

    PubMed

    Verma, S; Bhanja, S N; Pani, S K; Misra, A

    2014-04-01

    We analysed aerosol optical and physical properties in an urban environment (Kolkata) during winter monsoon pollution transport from nearby and far-off regions. Prevailing meteorological conditions, viz. low temperature and wind speed, and a strong downdraft of air mass, indicated weak dispersion and inhibition of vertical mixing of aerosols. Spectral features of WinMon aerosol optical depth (AOD) showed larger variability (0.68-1.13) in monthly mean AOD at short-wavelength (SW) channels (0.34-0.5 μm) compared to that (0.28-0.37) at long-wavelength (LW) channels (0.87-1.02 μm), thereby indicating sensitivity of WinMon AOD to fine aerosol constituents and the predominant contribution from fine aerosol constituents to WinMon AOD. WinMon AOD at 0.5 μm (AOD 0. 5) and Angstrom parameter ( α) were 0.68-0.82 and 1.14-1.32, respectively, with their highest value in December. Consistent with inference from spectral features of AOD, surface aerosol loading was primarily constituted of fine aerosols (size 0.23-3 μm) which was 60-70 % of aerosol 10- μm (size 0.23-10 μm) concentration. Three distinct modes of aerosol distribution were obtained, with the highest WinMon concentration at a mass median diameter (MMD) of 0.3 μm during December, thereby indicating characteristics of primary contribution related to anthropogenic pollutants that were inferred to be mostly due to contribution from air mass originating in nearby region having predominant emissions from biofuel and fossil fuel combustion. A relatively higher contribution from aerosols in the upper atmospheric layers than at the surface to WinMon AOD was inferred during February compared to other months and was attributed to predominant contribution from open burning emissions arising from nearby and far-off regions. A comparison of ground-based measurements with Moderate Resolution Imaging Spectroradiometer (MODIS) data showed an underestimation of MODIS AOD and α values for most of the days. Discrepancy in

  12. Aerosol bolus transport through a hollow airway cast by steady flow in different gases

    SciTech Connect

    Briant, J.K.; Lippmann, M. )

    1993-07-01

    Transport of aerosol through the airways of a hollow cast of a canine tracheobronchial tree was measured for steady flow in different gas mixtures. A small bolus of 0.5-[mu]m aerosol particles was inserted as a tracer of convective motion in the flow at the entrance of the trachea, and particles were collected and counted as they arrived at a flow-balanced sampling bag at a peripheral segment of the cast. Transport was fastest in the gas of highest kinematic viscosity (helium), and slowest in the gas of lowest kinematic viscosity (sulfur hexafluoride). This is consistent with the lubrication theory that describes an axial core in the divergent flow field of the bronchial tree. The finer core in helium transports the particles at a greater velocity to distal airways. Transport of gases through the in vivo respiratory tract should also be influenced by these fluid mechanics of convection resembling Poiseuille flow that is substantially modified according to lubrication theory. As predicted by some other investigators, gas and aerosol particles penetrate much deeper into the lungs than the volumetric depth of inhalation. 25 refs., 7 figs., 2 tabs.

  13. Systematic observations of long-range transport events and climatological backscatter profiles with the DWD ceilometer network

    NASA Astrophysics Data System (ADS)

    Mattis, Ina; Müller, Gerhard; Wagner, Frank; Hervo, Maxime

    2015-04-01

    The German Meteorological Service (DWD) operates a network of about 60 CHM15K-Nimbus ceilometers for cloud base height observations. Those very powerful ceilometers allow for the detection and characterization of aerosol layers. Raw data of all network ceilometers are transferred online to DWD's data analysis center at the Hohenpeißenberg Meteorological Observatory. There, the occurrence of aerosol layers from long-range transport events in the free troposphere is systematically monitored on daily basis for each single station. If possible, the origin of the aerosol layers is determined manually from the analysis of the meteorological situation and model output. We use backward trajectories as well as the output of the MACC and DREAM models for the decision, whether the observed layer originated in the Sahara region, from forest fires in North America or from another, unknown source. Further, the magnitude of the observed layers is qualitatively estimated taking into account the geometrical layer depth, signal intensity, model output and nearby sun photometer or lidar observations (where available). All observed layers are attributed to one of the categories 'faint', 'weak', 'medium', 'strong', or 'extreme'. We started this kind of analysis in August 2013 and plan to continue this systematic documentation of long-range transport events of aerosol layers to Germany on long-term base in the framework of our GAW activities. Most of the observed aerosol layers have been advected from the Sahara region to Germany. In the 15 months between August 2013 and November 2014 we observed on average 46 days with Sahara dust layers per station, but only 16 days with aerosol layers from forest fires. The occurrence of Sahara dust layers vary with latitude. We observed only 28 dusty days in the north, close to the coasts of North Sea and Baltic Sea. In contrast, in southern Germany, in Bavarian Pre-Alps and in the Black Forest mountains, we observed up to 59 days with dust. At

  14. Transport and scavenging of biomass burning aerosols in the maritime continent

    NASA Astrophysics Data System (ADS)

    Lee, H. H.; Wang, C.

    2014-12-01

    Biomass burning frequently occurs in summertime over the maritime continent, especially in Malaysia peninsula, Sumatra, and Borneo. Under certain weather conditions, particulate matters emitted from such fires cause degrade of air quality and thus occurrence of often weekly long haze in downwind locations such as Singapore. It is possible that these biomass burning aerosols may have influenced convective clouds in the maritime continent though such cases have not been well simulated and understood. In order to improve understanding of the spatiotemporal coverage and influence of biomass burning aerosols in the maritime continent, we have used the Weather Research and Forecasting (WRF) model to study the transport of biomass burning aerosols from Malaysia peninsula, Sumatra, and Borneo, using biomass burning emissions from the Fire INventory from NCAR (FINN) version 1.0. We choose to use emissions from the month of August because the annual emissions peak often occurs within this month. Based on a multi-year ensemble simulation, we have examined the influences of various meteorological regimes on the aerosol transport and wet removal.

  15. Sulfate aerosol as a potential transport medium of radiocesium from the Fukushima nuclear accident.

    PubMed

    Kaneyasu, Naoki; Ohashi, Hideo; Suzuki, Fumie; Okuda, Tomoaki; Ikemori, Fumikazu

    2012-06-01

    To date, areas contaminated by radionuclides discharged from the Fukushima Dai-ichi nuclear power plant accident have been mapped in detail. However, size of the radionuclides and their mixing state with other aerosol components, which are critical in their removal from the atmosphere, have not yet been revealed. We measured activity size distributions of (134)Cs and (137)Cs in aerosols collected 47 days after the accident at Tsukuba, Japan, and found that the activity median aerodynamic diameters of (134)Cs and (137)Cs in the first sample (April 28-May 12) were 0.54 and 0.53 μm, respectively, and those in the second sample (May 12-26) were both 0.63 μm. The activity size distributions of these radiocesium were within the accumulation mode size range and almost overlapped with the mass size distribution of non-sea-salt sulfate aerosol. From the analysis of other aerosol components, we found that sulfate was the potential transport medium for these radionuclides, and resuspended soil particles that attached radionuclides were not the major airborne radioactive substances at the time of measurement. This explains the relatively similar activity sizes of radiocesium measured at various sites during the Chernobyl accident. Our results can serve as basic data for modeling the transport/deposition of radionuclides.

  16. Features, Events, and Processes in UZ Flow and Transport

    SciTech Connect

    J.E. Houseworth

    2001-04-10

    Unsaturated zone (UZ) flow and radionuclide transport is a component of the natural barriers that affects potential repository performance. The total system performance assessment (TSPA) model, and underlying process models, of this natural barrier component capture some, but not all, of the associated features, events, and processes (FEPs) as identified in the FEPs Database (Freeze, et al. 2001 [154365]). This analysis and model report (AMR) discusses all FEPs identified as associated with UZ flow and radionuclide transport. The purpose of this analysis is to give a comprehensive summary of all UZ flow and radionuclide transport FEPs and their treatment in, or exclusion from, TSPA models. The scope of this analysis is to provide a summary of the FEPs associated with the UZ flow and radionuclide transport and to provide a reference roadmap to other documentation where detailed discussions of these FEPs, treated explicitly in TSPA models, are offered. Other FEPs may be screened out from treatment in TSPA by direct regulatory exclusion or through arguments concerning low probability and/or low consequence of the FEPs on potential repository performance. Arguments for exclusion of FEPs are presented in this analysis. Exclusion of specific FEPs from the UZ flow and transport models does not necessarily imply that the FEP is excluded from the TSPA. Similarly, in the treatment of included FEPs, only the way in which the FEPs are included in the UZ flow and transport models is discussed in this document. This report has been prepared in accordance with the technical work plan for the unsaturated zone subproduct element (CRWMS M&O 2000 [153447]). The purpose of this report is to document that all FEPs are either included in UZ flow and transport models for TSPA, or can be excluded from UZ flow and transport models for TSPA on the basis of low probability or low consequence. Arguments for exclusion are presented in this analysis. Exclusion of specific FEPs from UZ flow and

  17. Coupling aerosol optics to the MATCH (v5.5.0) chemical transport model and the SALSA (v1) aerosol microphysics module

    NASA Astrophysics Data System (ADS)

    Andersson, Emma; Kahnert, Michael

    2016-05-01

    A new aerosol-optics model is implemented in which realistic morphologies and mixing states are assumed, especially for black carbon particles. The model includes both external and internal mixing of all chemical species, it treats externally mixed black carbon as fractal aggregates, and it accounts for inhomogeneous internal mixing of black carbon by use of a novel "core-grey-shell" model. Simulated results of aerosol optical properties, such as aerosol optical depth, backscattering coefficients and the Ångström exponent, as well as radiative fluxes are computed with the new optics model and compared with results from an older optics-model version that treats all particles as externally mixed homogeneous spheres. The results show that using a more detailed description of particle morphology and mixing state impacts the aerosol optical properties to a degree of the same order of magnitude as the effects of aerosol-microphysical processes. For instance, the aerosol optical depth computed for two cases in 2007 shows a relative difference between the two optics models that varies over the European region between -28 and 18 %, while the differences caused by the inclusion or omission of the aerosol-microphysical processes range from -50 to 37 %. This is an important finding, suggesting that a simple optics model coupled to a chemical transport model can introduce considerable errors affecting radiative fluxes in chemistry-climate models, compromising comparisons of model results with remote sensing observations of aerosols, and impeding the assimilation of satellite products for aerosols into chemical-transport models.

  18. Transport of surgically produced aerosols in an operating room.

    PubMed

    Buchanan, C R; Dunn-Rankin, D

    1998-06-01

    The particle transport characteristics of two ventilation configurations commonly used in hospital operating rooms (ORs), cross-flow and impinging-flow ventilation, were investigated. The computational fluid dynamics software FLUENT was used to simulate turbulent airflow with mixed convection in a three-dimensional, rectangular OR. Two OR personnel, a patient, OR spotlights, an anesthetics cart, and an operating table were represented in the room. Heat loads from the personnel, patient, and lights affected the airflow through buoyancy. Particles produced at the operation site with various sizes and initial conditions were tracked through the room. A stochastic model was used to include the random effects of turbulence on particle trajectories. Simulation results show that heat loads from the personnel, patient, and OR spotlights had an important effect on the airflow through natural convection. Particle trajectories were influenced greatly by the flow field structure, particle launch position, and turbulence in the flow, and somewhat by particle size. However, particle paths were insensitive to the launch velocity. Virtually identical trajectories were obtained for particles with launch velocities ranging from 0 to 1 m/sec in magnitude. Changes in ventilation configuration dramatically affected particle transport. The cross-flow ventilation configuration performed better, based on the criteria of removing particles from the breathing zone of room occupants. Proper flow field design and contaminant source placement can be used to control particle transport. Numerical simulations allow quick and inexpensive comparisons between room designs and provide details about airflow and contaminant transport.

  19. Long-range-transported Saharan dust in the Caribbean - an electron microscopy perspective of aerosol composition and modification

    NASA Astrophysics Data System (ADS)

    Kandler, Konrad; Hartmann, Markus; Ebert, Martin; Weinbruch, Stephan; Weinzierl, Bernadett; Walser, Adrian; Sauer, Daniel; Wadinga Fomba, Khanneh

    2015-04-01

    -based - is composed of mainly silicates and minor amounts of Ca-rich and Fe-/Fe-Ti-rich particles (less than 10 % of dust fraction). The composition of the silicates indicates a major contribution of kaolinite (Al/Si atomic ratio between 0.6 and 1) and a minor contribution of quartz and feldspar particles. The inter-sample variation of the dust composition is generally low, pointing to a very thorough mixing from differently-composed Saharan sources. The temporal evolution of aerosol composition at Ragged Point shows a variation in dust abundance, but strong isolated events could not be identified. An airmass change induced by the passing by of a hurricane, however, is visible in sulfate abundance and their composition. Strong internally mixed particles of dust and sulfate or dust and sea-salt are very rare (up to 1 % of particles in the airborne samples), but a slight increasing tendency with decreasing altitude was found. In the lower MBL at Ragged point, dust/sea-salt mixtures are more frequent (in the same abundance range as pure dust particles). A first conclusion from the data set is that dust aging with respect to internal mixtures does not happen during the long-range transport across the Atlantic Ocean, but rather at the end during the down-mixing of mineral dust into the Caribbean MBL.

  20. Influence of aerosols on the life cycle of a radiation fog event. A numerical and observational study

    NASA Astrophysics Data System (ADS)

    Stolaki, S.; Haeffelin, M.; Lac, C.; Dupont, J.-C.; Elias, T.; Masson, V.

    2015-01-01

    Despite the knowledge gained on the physical processes dominating the formation, development and dissipation of radiation fog events, uncertainties still exist about the role of the microphysical processes related to aerosol characteristics. The objective of this work is to analyze the sensitivity of fog to aerosols through their impacts on the fog droplets. A radiation fog event that formed on 15/11/2011 at the SIRTA Observatory near Paris in the context of the 2011-2012 ParisFog field campaign is the basis of this study. The selected case is one that initially forms a few hundred meters above the surface and within half an hour lowers down to the surface. A combination of SIRTA's sophisticated observations and 1D numerical simulations is employed with the aim of better understanding the influence of thermodynamics and microphysics on the life-cycle of the fog event and the degree to which aerosol characteristics such as concentration of potentially activated aerosols, size and solubility affect its characteristics. It results that the model simulates fairly well the fog life cycle, with only one half hour advance in the onset and one hour in the dissipation at the surface. The quality of the reference simulation is evaluated against several in-situ and remote sensing measurements. A numerical sensitivity analysis shows that the fog characteristics are strongly influenced by the aerosols. Doubling (halving) the cloud condensation nuclei (CCN) number translates into a 160% increase (65% decrease) in the production of fog droplets, and a 60% increase (40% decrease) of the liquid water path (LWP). The aerosols influence up to 10% the fog geometrical thickness. The necessity for more detailed local forcings that will produce better thermohygrometric conditions in the upper levels above the formed fog layer is underlined, as well as the addition of microphysical measurements in the vertical that will allow to improve two-moment microphysics schemes.

  1. Impacts of intercontinental transport of aerosols on human mortality

    NASA Astrophysics Data System (ADS)

    Anenberg, S.; West, J. J.; Schulz, M.; Hemispheric Transport of Air Pollution (HTAP) modelers

    2011-12-01

    Fine particulate matter (PM2.5) is associated with deleterious health impacts, including premature death from cardiopulmonary disease and lung cancer. Although the lifetime of tropospheric PM2.5 is roughly only a week, observations and modeling studies demonstrate that PM2.5 can be transported long distances, impacting air quality and health on regional or global scales. We estimate the mortality impacts of 20% primary PM and PM precursor emission reductions in four major world regions - North America, Europe, East Asia, and South Asia. We use surface concentrations simulated by an ensemble of global chemical transport models convened by the Task Force on Hemispheric Transport of Air Pollution and epidemiologically-derived concentration-response functions to calculate mortality impacts. We estimate that while >90% of avoided premature deaths resulting from these emission reductions occur within the source region, about 9,600 annual avoided deaths occur in other parts of the world. Reducing emissions in Europe avoids the most extra-regional premature deaths, due to large downwind populations in relatively close proximity. Compared with a previous study of 20% ozone precursor emission reductions, we find that the impacts of intercontinental ozone are greater than or equal to those of PM2.5 for most source-receptor pairs, due to the longer atmospheric lifetime and greater transport efficiency for ozone. However, impacts of intercontinental PM2.5 are greater for source-receptor pairs not separated by an ocean, due to the stronger relationship of PM2.5 with mortality. We examine the sensitivity of estimated premature deaths to the shape and magnitude of the concentration-response function, as well as the inter-model variation in simulated PM2.5 responses to emission reductions.

  2. Simulating Secondary Inorganic Aerosols using the chemistry transport model MOCAGE version R2.15.0

    NASA Astrophysics Data System (ADS)

    Guth, J.; Josse, B.; Marécal, V.; Joly, M.

    2015-04-01

    In this study we develop a Secondary Inorganic Aerosol (SIA) module for the chemistry transport model MOCAGE developed at CNRM. Based on the thermodynamic equilibrium module ISORROPIA II, the new version of the model is evaluated both at the global scale and at the regional scale. The results show high concentrations of secondary inorganic aerosols in the most polluted regions being Europe, Asia and the eastern part of North America. Asia shows higher sulfate concentrations than other regions thanks to emissions reduction in Europe and North America. Using two simulations, one with and the other without secondary inorganic aerosol formation, the model global outputs are compared to previous studies, to MODIS AOD retrievals, and also to in situ measurements from the HTAP database. The model shows a better agreement in all geographical regions with MODIS AOD retrievals when introducing SIA. It also provides a good statistical agreement with in situ measurements of secondary inorganic aerosol composition: sulfate, nitrate and ammonium. In addition, the simulation with SIA gives generally a better agreement for secondary inorganic aerosols precursors (nitric acid, sulfur dioxide, ammonia) in particular with a reduction of the Modified Normalised Mean Bias (MNMB). At the regional scale, over Europe, the model simulation with SIA are compared to the in situ measurements from the EMEP database and shows a good agreement with secondary inorganic aerosol composition. The results at the regional scale are consistent with those obtained with the global simulations. The AIRBASE database was used to compare the model to regulated air quality pollutants being particulate matter, ozone and nitrogen dioxide concentrations. The introduction of the SIA in MOCAGE provides a reduction of the PM2.5 MNMB of 0.44 on a yearly basis and even 0.52 on a three spring months period (March, April, May) when SIA are maximum.

  3. Molecular characterization of free tropospheric aerosol collected at the Pico Mountain Observatory: a case study with a long-range transported biomass burning plume

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    Free tropospheric aerosol was sampled at the Pico Mountain Observatory located at 2225 m above mean sea level on Pico Island of the Azores archipelago in the North Atlantic. The observatory is located ~ 3900 km east and downwind of North America, which enables studies of free tropospheric air transported over long distances. Aerosol samples collected on filters from June to October 2012 were analyzed to characterize organic carbon, elemental carbon, and inorganic ions. The average ambient concentration of aerosol was 0.9 ± 0.7 μg m-3. On average, organic aerosol components represent the largest mass fraction of the total measured aerosol (60 ± 51%), followed by sulfate (23 ± 28%), nitrate (13 ± 10%), chloride (2 ± 3%), and elemental carbon (2 ± 2%). Water-soluble organic matter (WSOM) extracted from two aerosol samples (9/24 and 9/25) collected consecutively during a pollution event were analyzed using ultrahigh-resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Approximately 4000 molecular formulas were assigned to each of the mass spectra in the range of m/z 100-1000. The majority of the assigned molecular formulas had unsaturated structures with CHO and CHNO elemental compositions. FLEXPART retroplume analyses showed the sampled air masses were very aged (average plume age > 12 days). These aged aerosol WSOM compounds had an average O/C ratio of ~ 0.45, which is relatively low compared to O/C ratios of other aged aerosol. The increase in aerosol loading during the measurement period of 9/24 was linked to biomass burning emissions from North America by FLEXPART retroplume analysis and Moderate Resolution Imaging Spectroradiometer (MODIS) fire counts. This was confirmed with biomass burning markers detected in the WSOM and with the morphology and mixing state of particles as determined by scanning electron microscopy. The presence of markers characteristic of aqueous-phase reactions of phenolic species suggests

  4. Impacts of extreme weather events on transport infrastructure in Norway

    NASA Astrophysics Data System (ADS)

    Frauenfelder, Regula; Solheim, Anders; Isaksen, Ketil; Romstad, Bård; Dyrrdal, Anita V.; Ekseth, Kristine H. H.; Gangstø Skaland, Reidun; Harbitz, Alf; Harbitz, Carl B.; Haugen, Jan E.; Hygen, Hans O.; Haakenstad, Hilde; Jaedicke, Christian; Jónsson, Árni; Klæboe, Ronny; Ludvigsen, Johanna; Meyer, Nele K.; Rauken, Trude; Sverdrup-Thygeson, Kjetil

    2016-04-01

    With the latest results on expected future increase in air temperature and precipitation changes reported by the Intergovernmental Panel on Climate Change (IPCC), the climate robustness of important infrastructure is of raising concern in Norway, as well as in the rest of Europe. Economic consequences of natural disasters have increased considerably since 1950. In addition to the effect of demographic changes such as population growth, urbanization and more and more concentration of valuable assets, this increase is also related to an augmenting frequency of extreme events, such as storms, flooding, drought, and landslides. This change is also observable in Norway, where the increased frequency of strong precipitation has led to frequent flooding and landslide events during the last 20 years. A number of studies show that climate change causes an increase in both frequency and intensity of several types of extreme weather, especially when it comes to precipitation. Such extreme weather events greatly affect the transport infrastructure, with numerous and long closures of roads and railroads, in addition to damage and repair costs. Frequent closures of railroad and roads lead to delay or failure in delivery of goods, which again may lead to a loss of customers and/or - eventually - markets. Much of the Norwegian transport infrastructure is more than 50 years old and therefore not adequately dimensioned, even for present climatic conditions. In order to assess these problems and challenges posed to the Norwegian transport infrastructure from present-day and future extreme weather events, the project "Impacts of extreme weather events on infrastructure in Norway (InfraRisk)" was performed under the research Council of Norway program 'NORKLIMA', between 2009 and 2013. The main results of the project are: - Moderate to strong precipitation events have become more frequent and more intense in Norway over the last 50 years, and this trend continues throughout the 21st

  5. The long range transport of sulfurous aerosol to Scandinavia

    SciTech Connect

    Ottar, B.

    1980-01-01

    Results of the LRTAP program and other European studies are discussed which show that considerable long-range transport of air pollutants from the UK and central Europe to Scandinavia occurs. Data are examined which reveal that the sulfate deposition pattern in Scandinavia is largely governed by precipitation and wind direction and that sulfates deposition reaches maximum values of 3 to 5 metric tons/sq km in southern Scandinavia. The contribution from precipitation is found to outweigh the dry deposition, particularly in southern Norway.

  6. Frequency and Character of Extreme Aerosol Events in the Southwestern United States: A Case Study Analysis in Arizona

    PubMed Central

    Lopez, David H.; Rabbani, Michael R.; Crosbie, Ewan; Raman, Aishwarya; Arellano, Avelino F.; Sorooshian, Armin

    2016-01-01

    This study uses more than a decade’s worth of data across Arizona to characterize the spatiotemporal distribution, frequency, and source of extreme aerosol events, defined as when the concentration of a species on a particular day exceeds that of the average plus two standard deviations for that given month. Depending on which of eight sites studied, between 5% and 7% of the total days exhibited an extreme aerosol event due to either extreme levels of PM10, PM2.5, and/or fine soil. Grand Canyon exhibited the most extreme event days (120, i.e., 7% of its total days). Fine soil is the pollutant type that most frequently impacted multiple sites at once at an extreme level. PM10, PM2.5, fine soil, non-Asian dust, and Elemental Carbon extreme events occurred most frequently in August. Nearly all Asian dust extreme events occurred between March and June. Extreme Elemental Carbon events have decreased as a function of time with statistical significance, while other pollutant categories did not show any significant change. Extreme events were most frequent for the various pollutant categories on either Wednesday or Thursday, but there was no statistically significant difference in the number of events on any particular day or on weekends versus weekdays. PMID:27088005

  7. Monitoring aerosol elemental composition in particle size fractions of long-range transport

    NASA Astrophysics Data System (ADS)

    Metternich, P.; Georgii, H.-W.; Groeneveld, K. O.

    1983-04-01

    Collection of atmospheric samples was performed at Malta, a semi-remote environment in the Mediterranean, in case of long-range transport studies of pollutants and natural substances. Using PIXE as a non-destructive trace-element analytical tool, the elemental composition of these samples was determined. Atmospheric concentrations obtained in this study were of one magnitude higher than those observed over the open North Alantic in purely marine air. For most of the anomalously enriched elements in the Mediterranean aerosol, the high concentrations can be explained by long-range transport.

  8. Optical, physical and chemical properties of transported African mineral dust aerosols in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Denjean, Cyrielle; Di Biagio, Claudia; Chevaillier, Servanne; Gaimoz, Cécile; Grand, Noel; Loisil, Rodrigue; Triquet, Sylvain; Zapf, Pascal; Roberts, Greg; Bourrianne, Thierry; Torres, Benjamin; Blarel, Luc; Sellegri, Karine; Freney, Evelyn; Schwarzenbock, Alfons; Ravetta, François; Laurent, Benoit; Mallet, Marc; Formenti, Paola

    2014-05-01

    The transport of mineral dust aerosols is a global phenomenon with strong climate implications. Depending on the travel distance over source regions, the atmospheric conditions and the residence time in the atmosphere, various transformation processes (size-selective sedimentation, mixing, condensation of gaseous species, and weathering) can modify the physical and chemical properties of mineral dust, which, in turn, can change the dust's optical properties. The model predictions of the radiative effect by mineral dust still suffer of the lack of certainty of these properties, and their temporal evolution with transport time. Within the frame of the ChArMex project (Chemistry-Aerosol Mediterranean experiment, http://charmex.lsce.ipsl.fr/), two intensive airborne campaigns (TRAQA, TRansport and Air QuAlity, 18 June - 11 July 2012, and ADRIMED, Aerosol Direct Radiative Impact in the regional climate in the MEDiterranean region, 06 June - 08 July 2013) have been performed over the Central and Western Mediterranean, one of the two major transport pathways of African mineral dust. In this study we have set up a systematic strategy to determine the optical, physical and optical properties of mineral dust to be compared to an equivalent dataset for dust close to source regions in Africa. This study is based on airborne observations onboard the SAFIRE ATR-42 aircraft, equipped with state of the art in situ instrumentation to measure the particle scattering and backscattering coefficients (nephelometer at 450, 550, and 700 nm), the absorption coefficient (PSAP at 467, 530, and 660 nm), the extinction coefficient (CAPS at 530 nm), the aerosol optical depth (PLASMA at 340 to 1640 nm), the size distribution in the extended range 40 nm - 30 µm by the combination of different particle counters (SMPS, USHAS, FSSP, GRIMM) and the chemical composition obtained by filter sampling. The chemistry and transport model CHIMERE-Dust have been used to classify the air masses according to

  9. Transport of aerosols into the UTLS and their impact on the Asian monsoon region as seen in a global model simulation

    NASA Astrophysics Data System (ADS)

    Fadnavis, S.; Semeniuk, K.; Pozzoli, L.; Schultz, M. G.; Ghude, S. D.; Das, S.; Kakatkar, R.

    2013-09-01

    An eight-member ensemble of ECHAM5-HAMMOZ simulations for a boreal summer season is analysed to study the transport of aerosols in the upper troposphere and lower stratosphere (UTLS) during the Asian summer monsoon (ASM). The simulations show persistent maxima in black carbon, organic carbon, sulfate, and mineral dust aerosols within the anticyclone in the UTLS throughout the ASM (period from July to September), when convective activity over the Indian subcontinent is highest, indicating that boundary layer aerosol pollution is the source of this UTLS aerosol layer. The simulations identify deep convection and the associated heat-driven circulation over the southern flanks of the Himalayas as the dominant transport pathway of aerosols and water vapour into the tropical tropopause layer (TTL). Comparison of model simulations with and without aerosols indicates that anthropogenic aerosols are central to the formation of this transport pathway. Aerosols act to increase cloud ice, water vapour, and temperature in the model UTLS. Evidence of ASM transport of aerosols into the stratosphere is also found, in agreement with aerosol extinction measurements from the Halogen Occultation Experiment (HALOE) and Stratospheric Aerosol and Gas Experiment (SAGE) II. As suggested by the observations, aerosols are transported into the Southern Hemisphere around the tropical tropopause by large-scale mixing processes. Aerosol-induced circulation changes also include a weakening of the main branch of the Hadley circulation and a reduction of monsoon precipitation over India.

  10. New Lidar Capabilities in Space: An Overview of the Cloud-Aerosol Transport System (CATS)

    NASA Astrophysics Data System (ADS)

    McGill, M. J.; Yorks, J. E.; Hlavka, D. L.; Selmer, P. A.; Hart, W. D.; Palm, S. P.; Nowottnick, E. P.; Vaughan, M.; Rodier, S. D.; Colarco, P. R.; da Silva, A.; Buchard, V.

    2014-12-01

    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 late 2014. CATS is an elastic backscatter lidar operating in one of three science modes with three wavelengths (1064, 532, 355 nm) and HSRL capability at 532 nm. Depolarization measurements will be made at the 532 and 1064 nm wavelengths. The CATS science modes are described in Figure 1. 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. 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. A primary science objectives of CATS is to provide global aerosol and cloud vertical profile data in near real time to for assimilation in aerosol transport models such as the NASA GEOS-5 model. Furthermore, the vertical profiles of cloud and aerosol properties provided by CATS will complement current and future passive satellite sensors. Another important science objective of CATS is to advance technology in support of future mission development. CATS will employ 355 nm and HSRL capabilities, as well as depolarization at multiple wavelengths. These expanded measurement capabilities will provide the science community with new and improved global data products that have yet to be retrieved from space-based lidar. In preparation for launch, simulations of the CATS lidar signal are produced using GEOS5 model data to develop and test future data products. An example of the simulated CATS attenuated

  11. MBAS (Methylene Blue Active Substances) and LAS (Linear Alkylbenzene Sulphonates) in Mediterranean coastal aerosols: Sources and transport processes

    NASA Astrophysics Data System (ADS)

    Becagli, S.; Ghedini, C.; Peeters, S.; Rottiers, A.; Traversi, R.; Udisti, R.; Chiari, M.; Jalba, A.; Despiau, S.; Dayan, U.; Temara, A.

    2011-12-01

    Methylene Blue Active Substances (MBAS) and Linear Alkylbenzene Sulphonates (LAS) concentrations, together with organic carbon and ions were measured in atmospheric coastal aerosols in the NW Mediterranean Basin. Previous studies have suggested that the presence of surfactants in coastal aerosols may result in vegetation damage without specifically detecting or quantifying these surfactants. Coastal aerosols were collected at a remote site (Porquerolles Island-Var, France) and at a more anthropised site (San Rossore National Park-Tuscany, Italy). The chemical data were interpreted according to a comprehensive local meteorological analysis aiming to decipher the airborne source and transport processes of these classes of compounds. The LAS concentration (anthropogenic surfactants) was measured in the samples using LC-MS/MS, a specific analytical method. The values were compared with the MBAS concentration, determined by a non-specific analytical method. At Porquerolles, the MBAS concentration (103 ± 93 ng m -3) in the summer samples was significantly higher than in the winter samples. In contrast, LAS concentrations were rarely greater than in the blank filters. At San Rossore, the mean annual MBAS concentration (887 ± 473 ng m -3 in PM10) contributed about 10% to the total atmospheric particulate organic matter. LAS mean concentration in these same aerosol samples was 11.5 ± 10.5 ng m -3. A similar MBAS (529 ± 454 ng m -3) - LAS (7.1 ± 4.1 ng m -3 LAS) ratio of ˜75 was measured in the fine (PM2.5) aerosol fraction. No linear correlation was found between MBAS and LAS concentrations. At San Rossore site the variation of LAS concentrations was studied on a daily basis over a year. The LAS concentrations in the coarse fraction (PM10-2.5) were higher during strong sea storm conditions, characterized by strong air flow coming from the sea sector. These events, occurring with more intensity in winter, promoted the formation of primary marine aerosols containing LAS

  12. Transport and Mixing Patterns over Central California during the Carbonaceous Aerosol and Radiative Effects Study (CARES)

    SciTech Connect

    Fast, Jerome D.; Gustafson, William I.; Berg, Larry K.; Shaw, William J.; Pekour, Mikhail S.; Shrivastava, ManishKumar B.; Barnard, James C.; Ferrare, R.; Hostetler, Chris A.; Hair, John; Erickson, Matthew H.; Jobson, Tom; Flowers, Bradley; Dubey, Manvendra K.; Springston, Stephen R.; Pirce, Bradley R.; Dolislager, Leon; Pederson, J. R.; Zaveri, Rahul A.

    2012-02-17

    We describe the synoptic and regional-scale meteorological conditions that affected the transport and mixing of trace gases and aerosols in the vicinity of Sacramento, California during June 2010 when the Carbonaceous Aerosol and Radiative Effects Study (CARES) was conducted. The meteorological measurements collected by various instruments deployed during the campaign and the performance of the chemistry version of the Weather Research and Forecasting model (WRF-Chem) are both discussed. WRF-Chem was run daily during the campaign to forecast the spatial and temporal variation of carbon monoxide emitted from 20 anthropogenic source regions in California to guide aircraft sampling. The model is shown to reproduce the overall circulations and boundary-layer characteristics in the region, although errors in the upslope wind speed and boundary-layer depth contribute to differences in the observed and simulated carbon monoxide. Thermally-driven upslope flows that transported pollutants from Sacramento over the foothills of the Sierra Nevada occurred every afternoon, except during three periods when the passage of mid-tropospheric troughs disrupted the regional-scales flow patterns. The meteorological conditions after the passage of the third trough were the most favorable for photochemistry and likely formation of secondary organic aerosols. Meteorological measurements and model forecasts indicate that the Sacramento pollutant plume was likely transported over a downwind site that collected trace gas and aerosol measurements during 23 periods; however, direct transport occurred during only eight of these periods. The model also showed that emissions from the San Francisco Bay area transported by intrusions of marine air contributed a large fraction of the carbon monoxide in the vicinity of Sacramento, suggesting that this source likely affects local chemistry. Contributions from other sources of pollutants, such as those in the Sacramento Valley and San Joaquin Valley

  13. Transport and mixing patterns over Central California during the carbonaceous aerosol and radiative effects study (CARES)

    SciTech Connect

    Fast J. D.; Springston S.; Gustafson Jr., W. I.; Berg, L. K.; Shaw, W. J.; Pekour, M.; Shrivastava, M.; Barnard, J. C.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. A.; Erickson, M.; Jobson, B. T.; Flowers, B.; Dubey, M. K.; Pierce, R. B.; Dolislager, L.; Pederson, J.; Zaveri, R. A.

    2012-02-17

    We describe the synoptic and regional-scale meteorological conditions that affected the transport and mixing of trace gases and aerosols in the vicinity of Sacramento, California during June 2010 when the Carbonaceous Aerosol and Radiative Effects Study (CARES) was conducted. The meteorological measurements collected by various instruments deployed during the campaign and the performance of the chemistry version of the Weather Research and Forecasting model (WRF-Chem) are both discussed. WRF-Chem was run daily during the campaign to forecast the spatial and temporal variation of carbon monoxide emitted from 20 anthropogenic source regions in California to guide aircraft sampling. The model is shown to reproduce the overall circulations and boundary-layer characteristics in the region, although errors in the upslope wind speed and boundary-layer depth contribute to differences in the observed and simulated carbon monoxide. Thermally-driven upslope flows that transported pollutants from Sacramento over the foothills of the Sierra Nevada occurred every afternoon, except during three periods when the passage of mid-tropospheric troughs disrupted the regional-scale flow patterns. The meteorological conditions after the passage of the third trough were the most favorable for photochemistry and likely formation of secondary organic aerosols. Meteorological measurements and model forecasts indicate that the Sacramento pollutant plume was likely transported over a downwind site that collected trace gas and aerosol measurements during 23 time periods; however, direct transport occurred during only eight of these periods. The model also showed that emissions from the San Francisco Bay area transported by intrusions of marine air contributed a large fraction of the carbon monoxide in the vicinity of Sacramento, suggesting that this source likely affects local chemistry. Contributions from other sources of pollutants, such as those in the Sacramento Valley and San Joaquin

  14. The long-range transport of southern African aerosols to the tropical South Atlantic

    NASA Astrophysics Data System (ADS)

    Swap, R.; Garstang, M.; Macko, S. A.; Tyson, P. D.; Maenhaut, W.; Artaxo, P.; KâLlberg, P.; Talbot, R.

    1996-10-01

    Two episodes of long-range aerosol transport (4000 km) from southern Africa into the central tropical South Atlantic are documented. Stable nitrogen isotope analysis, multielemental analysis, and meteorological observations on local and regional scales are used to describe the observed surface aerosol chemistry during these transport episodes. The chemical, kinematic, and thermodynamic analyses suggest that for the central tropical South Atlantic, west Africa between 0° and 10°S is the primary air mass source region (over 50%) during austral spring. Over 70% of all air arriving in the lower and middle troposphere in the central tropical South Atlantic comes from a broad latitudinal band extending from 20°S to 10°N. Air coming from the east subsides and is trapped below the midlevel and trade wind inversion layers. Air from the west originates at higher levels (500 hPa) and contributes less than 30% of the air masses arriving in the central tropical South Atlantic. The source types of aerosols and precursor trace gases extend over a broad range of biomes from desert and savanna to the rain forest. During austral spring, over this broad region, processes include production from vegetation, soils, and biomass burning. The aerosol composition of air masses over and the atmospheric chemistry of the central South Atlantic is a function of the supply of biogenic, biomass burning, and aeolian emissions from tropical Africa. Rainfall is a common controlling factor for all three sources. Rain, in turn, is governed by the large-scale circulations which show pronounced interannual variability. The field measurements were taken in an extremely dry year and reflect the circulation and transport fields typical of these conditions.

  15. Properties of transported African mineral dust aerosols in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Denjean, Cyrielle; Chevaillier, Servanne; Gaimoz, Cécile; Grand, Noel; Triquet, Sylvain; Zapf, Pascal; Loisil, Rodrigue; Bourrianne, Thierry; Freney, Evelyn; Dupuy, Regis; Sellegri, Karine; Schwarzenbock, Alfons; Torres, Benjamin; Mallet, Marc; Cassola, Federico; Prati, Paolo; Formenti, Paola

    2015-04-01

    The transport of mineral dust aerosols is a global phenomenon with strong climate implications. Depending on the travel distance over source regions, the atmospheric conditions and the residence time in the atmosphere, various transformation processes (size-selective sedimentation, mixing, condensation of gaseous species, and weathering) can modify the physical and chemical properties of mineral dust, which, in turn, can change the dust's optical properties. The model predictions of the radiative effect by mineral dust still suffer of the lack of certainty of these properties, and their temporal evolution with transport time. Within the frame of the ChArMex project (Chemistry-Aerosol Mediterranean experiment, http://charmex.lsce.ipsl.fr/), one intensive airborne campaign (ADRIMED, Aerosol Direct Radiative Impact in the regional climate in the MEDiterranean region, 06 June - 08 July 2013) has been performed over the Central and Western Mediterranean, one of the two major transport pathways of African mineral dust. In this study we have set up a systematic strategy to determine the optical, physical and optical properties of mineral dust to be compared to an equivalent dataset for dust close to source regions in Africa. This study is based on airborne observations onboard the SAFIRE ATR-42 aircraft, equipped with state of the art in situ instrumentation to measure the particle scattering and backscattering coefficients (nephelometer at 450, 550, and 700 nm), the absorption coefficient (PSAP at 467, 530, and 660 nm), the extinction coefficient (CAPS at 530 nm), the aerosol optical depth (PLASMA at 340 to 1640 nm), the size distribution in the extended range 40 nm - 30 µm by the combination of different particle counters (SMPS, USHAS, FSSP, GRIMM) and the chemical composition obtained by filter sampling. The chemistry and transport model CHIMERE-Dust have been used to classify the air masses according to the dust origin and transport. Case studies of dust transport

  16. Study of aerosol optical properties at Kunming in southwest China and long-range transport of biomass burning aerosols from North Burma

    NASA Astrophysics Data System (ADS)

    Zhu, J.; Xia, X.; Che, H.; Wang, J.; Zhang, J.; Duan, Y.

    2016-03-01

    Seasonal variation of aerosol optical properties and dominant aerosol types at Kunming (KM), an urban site in southwest China, is characterized. Substantial influences of the hygroscopic growth and long-range transport of biomass burning (BB) aerosols on aerosol optical properties at KM are revealed. These results are derived from a detailed analysis of (a) aerosol optical properties (e.g. aerosol optical depth (AOD), columnar water vapor (CWV), single scattering albedo (SSA) and size distribution) retrieved from sunphotometer measurements during March 2012-August 2013, (b) satellite AOD and active fire products, (c) the attenuated backscatter profiles from the space-born lidar, and (d) the back-trajectories. The mean AOD440nm and extinction Angstrom exponent (EAE440 - 870) at KM are 0.42 ± 0.32 and 1.25 ± 0.35, respectively. Seasonally, high AOD440nm (0.51 ± 0.34), low EAE440 - 870 (1.06 ± 0.34) and high CWV (4.25 ± 0.97 cm) during the wet season (May - October) contrast with their counterparts 0.17 ± 0.11, 1.40 ± 0.31 and 1.91 ± 0.37 cm during the major dry season (November-February) and 0.53 ± 0.29, 1.39 ± 0.19, and 2.66 ± 0.44 cm in the late dry season (March-April). These contrasts between wet and major dry season, together with the finding that the fine mode radius increases significantly with AOD during the wet season, suggest the importance of the aerosol hygroscopic growth in regulating the seasonal variation of aerosol properties. BB and Urban/Industrial (UI) aerosols are two major aerosol types. Back trajectory analysis shows that airflows on clean days during the major dry season are often from west of KM where the AOD is low. In contrast, air masses on polluted days are from west (in late dry season) and east (in wet season) of KM where the AOD is often large. BB air mass is found mostly originated from North Burma where BB aerosols are lifted upward to 5 km and then subsequently transported to southwest China via prevailing westerly winds.

  17. Case study of extreme aerosol pollution events in the Paris area by synergy between optical measurements from multiple platforms

    NASA Astrophysics Data System (ADS)

    Totems, Julien; Chazette, Patrick; Royer, Philippe

    2013-04-01

    Major pollution events encountered in the Paris area are mainly due to anticyclonic conditions where air masses are blocked and recycled (horizontal wind speed less than 1 m.s-1) or advected from northestern Europe. Such events with aerosol optical thickness larger than 0.4 at 355 nm have been documented by in situ sensors (AirParif network), ground-based sunphotometers (Aeronet network) and fixed and mobile ground-based Rayleigh-Mie lidars. The first studied event occurred during the MEGAPOLI (Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation) summer experiment, on July 1st, 2009. Another favorable period for major pollution events is the spring season and we have highlighted two of them using the opportunity given by lidar experimental tests at LSCE in march 2011. Ground-based observations have been complemented by spaceborne measurements from MODIS and CALIPSO/CALIOP that give information on the spatial extent of the pollution plume in 3 dimensions. From this instrumental synergy we determine the aerosol optical properties (extinction coefficients in the atmospheric column, optical thickness, lidar ratio, ...). The probable aerosol sources have also been investigated using back-trajectories analyses computed by the HYSPLIT model (http://ready.arl.noaa.gov/HYSPLIT.php) ; they lie in the French Lorraine, Benelux, and German Saarland and Ruhr industrialized regions.

  18. Features, Events, and Processes in UZ and Transport

    SciTech Connect

    P. Persoff

    2004-11-06

    The purpose of this report is to evaluate and document the inclusion or exclusion of the unsaturated zone (UZ) features, events, and processes (FEPs) with respect to modeling that supports the total system performance assessment (TSPA) for license application (LA) for a nuclear waste repository at Yucca Mountain, Nevada. A screening decision, either ''Included'' or ''Excluded'', is given for each FEP, along with the technical basis for the screening decision. This information is required by the U.S. Nuclear Regulatory Commission (NRC) in 10 CFR 63.114 (d, e, and f) [DIRS 156605]. The FEPs deal with UZ flow and radionuclide transport, including climate, surface water infiltration, percolation, drift seepage, and thermally coupled processes. This analysis summarizes the implementation of each FEP in TSPA-LA (that is, how the FEP is included) and also provides the technical basis for exclusion from TSPA-LA (that is, why the FEP is excluded). This report supports TSPA-LA.

  19. Features, Events and Processes in UZ Flow and Transport

    SciTech Connect

    P. Persoff

    2005-08-04

    The purpose of this report is to evaluate and document the inclusion or exclusion of the unsaturated zone (UZ) features, events, and processes (FEPs) with respect to modeling that supports the total system performance assessment (TSPA) for license application (LA) for a nuclear waste repository at Yucca Mountain, Nevada. A screening decision, either Included or Excluded, is given for each FEP, along with the technical basis for the screening decision. This information is required by the U.S. Nuclear Regulatory Commission (NRC) in 10 CFR 63.114 (d, e, and f) [DIRS 173273]. The FEPs deal with UZ flow and radionuclide transport, including climate, surface water infiltration, percolation, drift seepage, and thermally coupled processes. This analysis summarizes the implementation of each FEP in TSPA-LA (that is, how the FEP is included) and also provides the technical basis for exclusion from TSPA-LA (that is, why the FEP is excluded). This report supports TSPA-LA.

  20. Observations of Aerosol Conditions Associated with Precipitation Events in the Remote Sierra Nevada Foothills

    NASA Astrophysics Data System (ADS)

    Collins, D. B.; Kingsmill, D.; Roberts, G. C.; Noblitt, S.; Prather, K. A.

    2011-12-01

    Recent investigations of atmospheric aerosols have suggested their importance in affecting clouds and precipitation patterns, especially in regions where anthropogenic contributions to aerosol loadings are large. Aerosols entrained into precipitating clouds have been shown to either enhance or suppress precipitation based on the characteristics of the cloud condensation nuclei (CCN) or ice nuclei (IN) introduced. Due to the inherent chemical dependence of CCN activity, the chemical composition of aerosols introduced into precipitating clouds will determine their effect on precipitation. This presentation will utilize ground-based chemical and physical measurements of aerosols and precipitation from multiple winter seasons gathered at Sugar Pine Dam (Foresthill, CA) as part of the CalWater experiment. The coupled behavior of landfalling frontal systems, regional terrain-parallel flow along the windward slopes of the Sierra Nevada (i.e., the Sierra Barrier Jet), and observed aerosol conditions in the Sierra Nevada foothills will be demonstrated and related issues explored. Temporally correlated changes in aerosol chemical composition with approaching winter storms may provide key insights into the evolution of the Sierra Barrier Jet, a dynamic feature that can have a major influence on orographically-forced precipitation in this region, and could provide clues to the coupling of Central Valley pollution with winter-time orographic precipitation episodes (or lack thereof). Gaining an overall understanding of the frequency and magnitude of the entrainment of Central Valley pollutants on winter storm systems will ultimately provide an estimate of how much aerosols affect precipitation in California.

  1. The long-range transport of atmospheric aerosols from South Asia to Himalayas

    NASA Astrophysics Data System (ADS)

    Cong, Zhiyuan; Kang, Shichang; Kawamura, Kimitaka

    2016-04-01

    High levels of carbonaceous aerosol exist over South Asia, the area adjacent to the Himalayas and Tibetan Plateau. Little is known about if they can be transported across the Himalayas, and as far inland as the Tibetan Plateau. To resolve such scientific questions, aerosol samples were collected weekly from August 2009 to July 2010 at Qomolangma (Mt. Everest) Station for Atmospheric and Environmental Observation and Research(QOMS, 4276 m a.s.l.). In the laboratory, major ions, elemental carbon, organic carbon, levoglucosan, water-soluble organic carbon, and organic acids were analyzed. The concentration levels of OC and EC at QOMS are comparable to those at high-elevation sites on the southern slopes of the Himalayas (Langtang and NCO-P), but 3 to 6 times lower than those at Manora Peak, India, and Godavari, Nepal. Sulfate was the most abundant anion species followed by nitrate. The dust loading, represented by Ca2+ concentration, was relatively constant throughout the year. OC, EC and other ionic species (NH+4 , K+, NO- and SO2-) exhibited a pronounced peak in the pre-monsoon period and a minimum in the monsoon season, being similar to the seasonal trends of aerosol compo-sition reported previously from the southern slope of the Himalayas. The strong correlation of OC and EC in QOMS aerosols with K+ and levoglucosan indicates that they mainly originated from biomass burning. Molecular distributions of dicarboxylic acids and related compounds (malonic acid/ succinic acid, maleic acid/fumaric acid) further support this finding. The fire spots observed by MODIS and backward air-mass trajectories further demonstrate that in pre-monsoon season, agricultural and forest fires in northern India and Nepal were most likely sources of carbonaceous aerosol at QOMS. In addition to large-scale atmospheric circulation, the unique mountain/valley breeze system can also have an important effect on air-pollutant transport.With the consideration of the darkening force of

  2. Atmospheric Modelling of Aerosols Long-Range Transport over the Himalayas

    NASA Astrophysics Data System (ADS)

    Surapipith, V.; Adhikary, B.; Bhave, P.; Panday, A. K.; Mukherji, A.

    2014-12-01

    An Atmospheric Modelling System has been set up at International Centre for Integrated Mountain Development (ICIMOD) Headquarters in Kathmandu, Nepal, for the assessment of air quality in the Hindukush Himalaya region. The Weather Research and Forecasting with Chemistry (WRF-Chem) model version 3.6 is being implemented over a regional domain stretching across 4995 x 4455 km centred at Kathmandu, where an intensive field campaign, Sustainable Atmosphere for the Kathmandu Valley (SusKat) took place from December 2012 to February 2013. Seven stations around the valley collected data on meteorology and chemical parameters. WRF-Chem simulation are carried out for the winter time period at high horizontal resolution (1 km × 1 km), which is achieved by nesting the domain of interest, e.g. Kathmandu Valley, inside three coarser domains. Model validation is performed against the field data as well as satellite data, focusing on aerosols. The challenge of capturing the necessary atmospheric processes is discussed. The effort aims for a better understanding of atmospheric processes and aerosol impacts, as well as the impact of long-range transport, particularly of black carbon aerosol upon the radiative budget over the Himalayan glaciers. The rapid melting of Himalayan glaciers and snowfields, and the shrinkage of permafrost as noticed by glaciologists is a concern. Based on physically adjusted schemes, the WRF meteorological model performs well with Pearson correlation coefficients higher than 0.8 for temperature and solar radiation, although it has a tendency to overestimate wind speed. The WRF with chemistry is then used with local and regional emission databases, in combination and after comparison with the global inventory, as input for describing the long-range transport of aerosols. Improved aerosol prediction will allow us to provide crucial information needed for mitigation and adaptation strategies that save people's lives across the Himalaya. The regional

  3. The long-range transport of atmospheric aerosols from South Asia to Himalayas

    NASA Astrophysics Data System (ADS)

    Cong, Zhiyuan; Kang, Shichang; Kawamura, Kimitaka

    2016-04-01

    High levels of carbonaceous aerosol exist over South Asia, the area adjacent to the Himalayas and Tibetan Plateau. Little is known about if they can be transported across the Himalayas, and as far inland as the Tibetan Plateau. To resolve such scientific questions, aerosol samples were collected weekly from August 2009 to July 2010 at Qomolangma (Mt. Everest) Station for Atmospheric and Environmental Observation and Research(QOMS, 4276 m a.s.l.). In the laboratory, major ions, elemental carbon, organic carbon, levoglucosan, water-soluble organic carbon, and organic acids were analyzed. The concentration levels of OC and EC at QOMS are comparable to those at high-elevation sites on the southern slopes of the Himalayas (Langtang and NCO-P), but 3 to 6 times lower than those at Manora Peak, India, and Godavari, Nepal. Sulfate was the most abundant anion species followed by nitrate. The dust loading, represented by Ca2+ concentration, was relatively constant throughout the year. OC, EC and other ionic species (NH+4 , K+, NO‑ and SO2‑) exhibited a pronounced peak in the pre-monsoon period and a minimum in the monsoon season, being similar to the seasonal trends of aerosol compo-sition reported previously from the southern slope of the Himalayas. The strong correlation of OC and EC in QOMS aerosols with K+ and levoglucosan indicates that they mainly originated from biomass burning. Molecular distributions of dicarboxylic acids and related compounds (malonic acid/ succinic acid, maleic acid/fumaric acid) further support this finding. The fire spots observed by MODIS and backward air-mass trajectories further demonstrate that in pre-monsoon season, agricultural and forest fires in northern India and Nepal were most likely sources of carbonaceous aerosol at QOMS. In addition to large-scale atmospheric circulation, the unique mountain/valley breeze system can also have an important effect on air-pollutant transport.With the consideration of the darkening force of

  4. Features, Events, and Processes in SZ Flow and Transport

    SciTech Connect

    K. Economy

    2004-11-16

    This analysis report evaluates and documents the inclusion or exclusion of the saturated zone (SZ) features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment (TSPA) for license application (LA) of a nuclear waste repository at Yucca Mountain, Nevada. A screening decision, either ''Included'' or ''Excluded'', is given for each FEP along with the technical basis for the decision. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.114 (d), (e), (f) (DIRS 156605). This scientific report focuses on FEP analysis of flow and transport issues relevant to the SZ (e.g., fracture flow in volcanic units, anisotropy, radionuclide transport on colloids, etc.) to be considered in the TSPA model for the LA. For included FEPs, this analysis summarizes the implementation of the FEP in TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from TSPA-LA (i.e., why the FEP is excluded).

  5. Features, Events, and Processes in SZ Flow and Transport

    SciTech Connect

    S. Kuzio

    2005-08-20

    This analysis report evaluates and documents the inclusion or exclusion of the saturated zone (SZ) features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment (TSPA) for license application (LA) of a nuclear waste repository at Yucca Mountain, Nevada. A screening decision, either Included or Excluded, is given for each FEP along with the technical basis for the decision. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.11(d), (e), (f) [DIRS 173273]. This scientific report focuses on FEP analysis of flow and transport issues relevant to the SZ (e.g., fracture flow in volcanic units, anisotropy, radionuclide transport on colloids, etc.) to be considered in the TSPA model for the LA. For included FEPs, this analysis summarizes the implementation of the FEP in TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from TSPA-LA (i.e., why the FEP is excluded).

  6. Sequence of Pathogenic Events in Cynomolgus Macaques Infected with Aerosolized Monkeypox Virus

    PubMed Central

    Hall, G.; Pearson, G.; Rayner, E.; Graham, V. A.; Steeds, K.; Bewley, K. R.; Hatch, G. J.; Dennis, M.; Taylor, I.; Roberts, A. D.; Funnell, S. G. P.; Vipond, J.

    2015-01-01

    ABSTRACT To evaluate new vaccines when human efficacy studies are not possible, the FDA's “Animal Rule” requires well-characterized models of infection. Thus, in the present study, the early pathogenic events of monkeypox infection in nonhuman primates, a surrogate for variola virus infection, were characterized. Cynomolgus macaques were exposed to aerosolized monkeypox virus (105 PFU). Clinical observations, viral loads, immune responses, and pathological changes were examined on days 2, 4, 6, 8, 10, and 12 postchallenge. Viral DNA (vDNA) was detected in the lungs on day 2 postchallenge, and viral antigen was detected, by immunostaining, in the epithelium of bronchi, bronchioles, and alveolar walls. Lesions comprised rare foci of dysplastic and sloughed cells in respiratory bronchioles. By day 4, vDNA was detected in the throat, tonsil, and spleen, and monkeypox antigen was detected in the lung, hilar and submandibular lymph nodes, spleen, and colon. Lung lesions comprised focal epithelial necrosis and inflammation. Body temperature peaked on day 6, pox lesions appeared on the skin, and lesions, with positive immunostaining, were present in the lung, tonsil, spleen, lymph nodes, and colon. By day 8, vDNA was present in 9/13 tissues. Blood concentrations of interleukin 1ra (IL-1ra), IL-6, and gamma interferon (IFN-γ) increased markedly. By day 10, circulating IgG antibody concentrations increased, and on day 12, animals showed early signs of recovery. These results define early events occurring in an inhalational macaque monkeypox infection model, supporting its use as a surrogate model for human smallpox. IMPORTANCE Bioterrorism poses a major threat to public health, as the deliberate release of infectious agents, such smallpox or a related virus, monkeypox, would have catastrophic consequences. The development and testing of new medical countermeasures, e.g., vaccines, are thus priorities; however, tests for efficacy in humans cannot be performed because it

  7. Molecular characterization of free tropospheric aerosol collected at the Pico Mountain Observatory: a case study with long range transported biomass burning plumes

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    Free tropospheric aerosol was sampled at the Pico Mountain Observatory located at 2225 m a.m.s.l. on Pico Island of the Azores archipelago in the North Atlantic. The observatory (38°28'15'' N; 28°24'14'' W) is located ∼3900 km east and downwind of North America, which enables studies of free tropospheric air transported over long distances, mainly from North America. Aerosol samples collected on filters from June to October 2012 were analyzed to characterize organic carbon, elemental carbon and inorganic ion species. The average ambient concentration of aerosol was 0.9 μg m-3; on average organic aerosol contributes the majority of mass (57%), followed by sulfate (21%) and nitrate (17%). Filter-collected aerosol measurements were positively correlated (with an r2 ≥ 0.80) with continuous aerosol measurements of black carbon, aerosol light scattering and number concentration. Water-soluble organic carbon (WSOC) species extracted from two aerosol samples (9/24 and 9/25) collected consecutively during a pollution event were analyzed using ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry. FLEXPART retroplume analysis shows the sampled air masses were very aged (average plume age > 12 days). Approximately 4000 molecular formulas were assigned to each of the mass spectra in the range of m/z 100-1000. The majority of the assigned molecular formulas have unsaturated structures with CHO and CHNO elemental compositions. These aged WSOC compounds have an average O / C ratio of ∼0.45, which is relatively low compared to O / C ratios of other aged aerosol and might be the result of evaporation and increased fragmentation during long-range transport. The increase in aerosol loading during the measurement period of 9/24 was linked to biomass burning emissions from North America by FLEXPART retroplume analysis and Moderate Resolution Imaging Spectroradiometer (MODIS) fire counts. This was confirmed with biomass burning markers detected in

  8. Characteristics of 14C and 13C of carbonate aerosols in dust storm events in China

    NASA Astrophysics Data System (ADS)

    Chen, Bing; Jie, Dongmei; Shi, Meinan; Gao, Pan; Shen, Zhenxing; Uchida, Masao; Zhou, Liping; Liu, Kexin; Hu, Ke; Kitagawa, Hiroyuki

    2015-10-01

    In contrast with its decrease in western China deserts, the dust storm event in eastern China, Korea, and Japan shows an increase in frequency. Although the drylands in northeastern China have been recognized as an important dust source, the relative contributions of dust transport from the drylands and deserts are inconclusive, thus the quantification of dust storm sources in downwind area remains a challenge. We measured the 14C and 13C contents in carbonates of dust samples from six sites in China, which were collected for the duration of dust storm events in drylands, deserts, and urban areas. The δ13C of the dryland dust samples considerably varied in a range of - 9.7 to - 5.0‰, which partly overlapped the desert dust carbonate δ13C ranges. The 14C content of the dryland dust carbonates showed a narrow range of 60.9 ± 4.0 (as an average and 1 SD of five samples) percent modern carbon (pMC), indicating the enrichment of modern carbonate. Dust samples in desert regions contained relatively aged carbonates with the depleting 14C showing of 28.8 ± 3.3 pMC. After the long-range transport of the western China desert dust plume, the carbonates collected at the southern China remained the depletion of 14C (33.5 ± 5.3 pMC) as in the desert regions. On the other hand, the samples of dust storm events at the urban areas of eastern China showed an enrichment of 14C contents (46.2 ± 5.0 pMC, n = 7), which might be explained by the stronger contribution of modern-carbonate-rich dryland dust.

  9. Vertical Structure, Transport, and Mixing of Ozone and Aerosols Observed During NEAQS/ICARTT 2004

    NASA Astrophysics Data System (ADS)

    Senff, C. J.; Hardesty, R. M.; Brewer, W. A.; Alvarez, R. J.; Sandberg, S. P.; Tucker, S. C.; Intrieri, J. M.; Marchbanks, R. D.; McCarty, B. J.; Banta, R. M.; Darby, L. S.; White, A. B.

    2005-12-01

    During the 2004 New England Air Quality Study (NEAQS), which was conducted within the framework of the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) field experiment, airborne and shipborne lidar remote sensing instruments were deployed to characterize the 3-dimensional structure of ozone, aerosol, and low-level wind fields in the New England region. The 2004 measurements confirmed findings from the smaller-scale NEAQS 2002 experiment: the vertical structure and transport patterns of pollutant plumes from the Boston and New York City urban areas are strongly modified when they are advected over the Gulf of Maine. Because of strong vertical wind shear and a very stable atmosphere over the cold ocean water the plumes tend to get sheared apart and the resulting pieces of the plumes stay confined in layers aloft, isolated from the surface. Most notably, ozone concentrations aloft are very often significantly higher than ozone levels near the ocean surface. These elevated pollution plumes over the Gulf of Maine can affect air quality in coastal New England only when they are transported back over land. This can be accomplished by the large-scale flow or by local circulations such as the sea breeze. Once over land the elevated plumes may impact surface air quality by direct transport to higher terrain (e.g., Cadillac Mountain, ME) or by being fumigated down to the surface. Alternatively, but probably more rarely, an elevated pollution plume over the ocean may be mixed down to the surface by mechanically generated turbulence and then transported back to land within the marine boundary layer. We will use airborne and shipborne lidar remote sensing data to characterize the vertical distribution of ozone and aerosols over coastal New England, in particular the difference in plume structure over land and water. We will also show observational evidence for several of the processes described above that may mix down and transport

  10. Analysis of the Impact of Major Dust Events on the Aerosols Characteristics over Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Farahat, Ashraf; El-Askary, Hesham; Al-Shaibani, Abdulaziz; Hariri, Mustafa M.

    2015-04-01

    The Kingdom of Saudi Arabia is a major source of atmospheric dust. Frequent dust storms blow up and significantly affect human activities, airports and citizens' health. Aerosols optical and physical characteristics are influenced by major dust storms outbreaks. In this, paper, ground based AERONET measurements are integrated with space-borne sensors, namely MODIS and CALIPSO to analyze aerosols' characteristics during March - May of 2009 where a massive dust storm blew up and caused a widespread heavy atmospheric dust load over Saudi Arabia and the same period during 2010, where less dust activities were reported. The MODIS Deep Blue AOD analysis showed similar aerosols pattern over the land, however a substantial variance in aerosol loading during March - May 2009 compared with the same period in 2010 was observed. The angstrom exponent analysis showed that the majority of aerosol measurements in 2009 and 2010 are dominated by coarse-mode particles with angstrom exponent < 0.5. Detailed analysis of aerosol optical properties shows significant influence of coarse mode particles in the enhanced aerosol loading in 2009. The volume depolarization rations (VDR) derived from CALIPSO backscattering measurements is used to find latitudinal profile of mean aerosol optical depth to indicate the type of particles and to discriminate spherical aerosols with non-spherical particles. Acknowledgement The authors would like to acknowledge the support provided by the King Abdel Aziz City for Science & Technology (KACST) for funding this work under grant No. (MT-32-76). The support provided by the Deanship of Research at King Fahd University of Petroleum & Minerals (KFUPM) is gratefully acknowledged.

  11. Assessing the influence of secondary organic aerosols on long-range atmospheric PAH transport

    NASA Astrophysics Data System (ADS)

    Friedman, C. L.; Selin, N. E.

    2013-12-01

    We incorporate recent experimental findings on the synergy between secondary organic aerosols (SOA) and polycyclic aromatic hydrocarbons (PAHs) in a global atmospheric chemical transport model to test the influence of different gas-particle partitioning parameterizations on long-range atmospheric transport of PAHs. PAHs, byproducts of organic combustion, are toxic compounds that have been measured in areas distant from sources, such as the Arctic. Historically, the transport of PAHs in the atmosphere has been modeled by assuming that PAHs instantaneously and reversibly equilibrate between the gas phase and a particulate phase, with observed particulate fractions often times exceeding model results for unknown reasons. Recently obtained laboratory-based findings suggest PAHs become trapped in SOA particles during SOA formation and are thus prevented from evaporation and/or oxidation, possibly explaining discrepancies between observed and modeled particulate fractions. Here, we use the global atmospheric chemical transport model GEOS-Chem to investigate whether incorporation of pyrene, a four-ring PAH, into SOA upon formation better represents atmospheric long-range transport and gas-particle speciation of PAHs compared to our default partitioning scheme, in which PAHs instantaneously equilibrate between the gas phase, primary organic carbon aerosols (OC), and black carbon aerosols (BC). In general, we find that BC plays an important role in pyrene transport and gas-particle partitioning, with a model that includes BC producing the best match to observed seasonal variation and magnitude of pyrene particulate fraction. Incorporation of 100% of pyrene into SOA upon emission with fractional evaporation thereafter results in a reasonable match to observed total pyrene concentrations in the northern hemisphere mid-latitudes, but severely overestimates particulate fraction. Assuming that pyrene partitions to SOA following an octanol-air equilibrium partition coefficient

  12. Dust aerosol characterization and transport features based on combined ground-based, satellite and model-simulated data

    NASA Astrophysics Data System (ADS)

    Vijayakumar, K.; Devara, P. C. S.; Rao, S. Vijaya Bhaskara; Jayasankar, C. K.

    2016-06-01

    In this paper, we study aerosol characteristics over an urban station in Western India, during a dust event that occurred between 19 and 26 March 2012, with the help of ground-based and satellite measurements and model simulation data. The aerosol parameters are found to change significantly during dust events and they suggest dominance of coarse mode aerosols. The fine mode fraction, size distribution and single scattering albedo reveal that dust (natural) aerosols dominate the anthropogenic aerosols over the study region. Ground-based measurements show drastic reduction in visibility on the dust-laden day (22 March 2012). Additionally, HYSPLIT model and satellite daily data have been used to trace the source, path and spatial extent of dust storm events. Most of the dust aerosols, during the study period, travel from west-to-east pathway from source-to-sink region. Furthermore, aerosol vertical profiles from CALIPSO and synoptic meteorological parameters from ECMWF re-analysis data reveal a layer of thick dust extending from surface to an altitude of about 4 km, and decrease in temperature and increase in specific humidity, respectively. The aerosol radiative forcing calculations indicate more cooling at the surface and warming in the atmosphere during dust event. The results of satellite observations are found to have good consistency with ground-based air quality measurements. Synthesis of satellite data integrated with ground-based observations, supplemented by model analysis, is found to be a promising technique for improved understanding of dust storm phenomenon and its impact on regional climate.

  13. EPISODIC EVENTS: THE EFFECT OF FLOODS ON NUTRIENT TRANSPORT IN A NORTHWESTERN, USA ESTUARY

    EPA Science Inventory

    To estimate the effects of storms on nutrient transport, dissolved nutrients and suspended sediment loads were measured relative to stream discharge in the Yaquina River, OR for three storm events. Episodic events, particularly high rainfall or flood events may transport high di...

  14. Evaluating the aerosol indirect effect in WRF-Chem simulations of the January 2013 Beijing air pollution event.

    NASA Astrophysics Data System (ADS)

    Peckham, Steven; Grell, Georg; Xie, Ying; Wu, Jian-Bin

    2015-04-01

    In January 2013, an unusual weather pattern over Northern China produced unusually cool, moist conditions for the region. Recent peer-reviewed scientific manuscripts report that during this time period, Beijing experienced a historically severe haze and smog event with observed monthly average fine particulate matter (PM2.5) concentrations exceeding 225 micrograms per cubic meter. MODIS satellite observations produced AOD values of approximately 1.5 to 2 for the same time. In addition, over eastern and northern China record-breaking hourly average PM2.5 concentrations of more than 700 μg m-3 were observed. Clearly, the severity and persistence of this air pollution episode has raised the interest of the scientific community as well as widespread public attention. Despite the significance of this and similar air pollution events, several questions regarding the ability of numerical weather prediction models to forecast such events remain. Some of these questions are: • What is the importance of including aerosols in the weather prediction models? • What is the current capability of weather prediction models to simulate aerosol impacts upon the weather? • How important is it to include the aerosol feedbacks (direct and indirect effect) in the numerical model forecasts? In an attempt to address these and other questions, a Joint Working Group of the Commission for Atmospheric Sciences and the World Climate Research Programme has been convened. This Working Group on Numerical Experimentation (WGNE), has set aside several events of interest and has asked its members to generate numerical simulations of the events and examine the results. As part of this project, weather and pollution simulations were produced at the NOAA Earth System Research Laboratory using the Weather Research and Forecasting (WRF) chemistry model. These particular simulations include the aerosol indirect effect and are being done in collaboration with a group in China that will produce

  15. Organic aerosol evolution and transport observed at Mt. Cimone (2165 m a.s.l.), Italy, during the PEGASOS campaign

    NASA Astrophysics Data System (ADS)

    Rinaldi, M.; Gilardoni, S.; Paglione, M.; Sandrini, S.; Fuzzi, S.; Massoli, P.; Bonasoni, P.; Cristofanelli, P.; Marinoni, A.; Poluzzi, V.; Decesari, S.

    2015-10-01

    High-resolution aerosol mass spectrometer measurements were performed, for the first time, at the Mt. Cimone Global Atmosphere Watch (GAW) station between June and July 2012, within the EU project PEGASOS and the ARPA-Emilia-Romagna project SUPERSITO. Submicron aerosol was dominated by organics (63 %), with sulfate, ammonium and nitrate contributing the remaining 20, 9 and 7 %, respectively. Organic aerosol (OA) was in general highly oxygenated, consistent with the remote character of the site; our observations suggest that oxidation and secondary organic aerosol (SOA) formation processes occurred during aerosol transport to high altitudes. All of the aerosol component concentrations as well as the OA elemental ratios showed a clear daily trend, driven by the evolution of the planetary boundary layer (PBL) and by the mountain wind regime. Higher loadings and lower OA oxidation levels were observed during the day, when the site was within the PBL, and therefore affected by relatively fresh aerosol transported from lower altitudes. Conversely, lower loadings and higher OA oxidation levels were observed at night, when the top of Mt. Cimone resided in the free troposphere although affected by the transport of residual layers on several days of the campaign. Analysis of the elemental ratios in a Van Krevelen space shows that OA oxidation follows a slope comprised between -0.5 and -1, consistent with addition of carboxylic groups, with or without fragmentation of the parent molecules. The increase of carboxylic groups during OA ageing is confirmed by the increased contribution of organic fragments containing more than one oxygen atom in the free troposphere night-time mass spectra. Finally, positive matrix factorization was able to deconvolve the contributions of relatively fresh OA (OOAa) originating from the PBL, more aged OA (OOAb) present at high altitudes during periods of atmospheric stagnation, and very aged aerosols (OOAc) transported over long distances in the

  16. Long-range transport of aerosols from agriculture crop residue burning in Indo-Gangetic Plains—A study using LIDAR, ground measurements and satellite data

    NASA Astrophysics Data System (ADS)

    Badarinath, K. V. S.; Kumar Kharol, Shailesh; Rani Sharma, Anu

    2009-01-01

    Agriculture crop residue burning in tropics is an important source of atmospheric aerosols and monitoring their long-range transport is an important element in climate change studies. Synchronous measurements using micro-pulsed lidar, MICROTOPS-II sun photometer, multi-filter rotating shadow band radiometer (MFRSR) on aerosol optical depth and ground reaching solar irradiance were carried at an urban location in central region of India. Aerosol backscatter profiles obtained from micro-pulse lidar showed elevated aerosol layers up to ~3 km on certain days during October 2007. Satellite data observations on aerosol properties suggested transport of particles from agriculture crop residue burning in Indo-Gangetic Plains over large regions. Radiative forcing of aerosols estimated from SBDART model with input information on aerosol chemical properties, aerosol optical depth and single scattering albedo and broadband solar irradiance measurements using MFRSR showed good correlation (R=0.98).

  17. Long Range Transport of Amazon Aerosol in the Free Troposphere: Influence of Amazon Combustion Aerosol on CCN in the Pacific Marine Boundary Layer

    NASA Astrophysics Data System (ADS)

    Howell, S. G.; Clarke, A. D.; Freitag, S.; Kapustin, V.; Hudson, J.; Campos, T.; Pollack, I. B.; Heizer, C. G.; Weinheimer, A. J.

    2008-12-01

    The Pacific Atmosphere Sulfur Experiment (PASE, Sept. 2007) on the NCAR C-130 aircraft was based in the Equatorial Pacific to explore the remote marine sulfur cycle. We investigated sources that control particle number and cloud condensation nuclei, CCN, in the clean marine boundary layer (MBL). Earlier studies here demonstrated particle number above the MBL was dominated by natural production of new volatile particles in cloud outflow. However, during PASE we also found coated refractory aerosol (non-volatile at 350C) aloft were linearly related to ozone concentrations and were effective CCN at 0.2% supersaturation. These aerosol had larger diameters than naturally produced volatile aerosol and trajectory analysis traced them back to deep convection in biomass burning haze over the Amazon basin over 10,000km away. These refractory soot and/or organic aerosol appear to be detrained from deep convective clouds after the near- source scavenging of larger sizes that dominate the smoke/haze aerosol mass. Following transport and once mixed into MBL they were found to account for as much as 30% of the CCN at the value of 0.2%S (a typical value for small trade-wind cumulus clouds). Hence, cloud-scavenged combustion derived aerosol, too small to be detectable optically in satellite plumes, appears to provide seed nuclei for CCN in the remote marine boundary layer. This acts over hemispheric scales for this region and presumably elsewhere. Hence; various mechanisms including convective scavenging, long range transport, particle production aloft, entrainment into the MBL, boundary layer nucleation and sea-salt production all need to be considered in modeling the MBL CCN population.

  18. Effects of crop residue burning on aerosol properties, plume characteristics, and long-range transport over northern India

    NASA Astrophysics Data System (ADS)

    Kaskaoutis, D. G.; Kumar, S.; Sharma, D.; Singh, R. P.; Kharol, S. K.; Sharma, M.; Singh, A. K.; Singh, S.; Singh, Atinderpal; Singh, D.

    2014-05-01

    Aerosol emissions from biomass burning are of specific interest over the globe due to their strong radiative impacts and climate implications. The present study examines the impact of paddy crop residue burning over northern India during the postmonsoon (October-November) season of 2012 on modification of aerosol properties, as well as the long-range transport of smoke plumes, altitude characteristics, and affected areas via the synergy of ground-based measurements and satellite observations. During this period, Moderate Resolution Imaging Spectroradiometer (MODIS) images show a thick smoke/hazy aerosol layer below 2-2.5 km in the atmosphere covering nearly the whole Indo-Gangetic Plains (IGP). The air mass trajectories originating from the biomass-burning source region over Punjab at 500 m reveal a potential aerosol transport pathway along the Ganges valley from west to east, resulting in a strong aerosol optical depth (AOD) gradient. Sometimes, depending upon the wind direction and meteorological conditions, the plumes also influence central India, the Arabian Sea, and the Bay of Bengal, thus contributing to Asian pollution outflow. The increased number of fire counts (Terra and Aqua MODIS data) is associated with severe aerosol-laden atmospheres (AOD500 nm > 1.0) over six IGP locations, high values of Ångström exponent (>1.2), high particulate mass 2.5 (PM2.5) concentrations (>100-150 µgm-3), and enhanced Ozone Monitoring Instrument Aerosol Index gradient (~2.5) and NO2 concentrations (~6 × 1015 mol/cm2), indicating the dominance of smoke aerosols from agricultural crop residue burning. The aerosol size distribution is shifted toward the fine-mode fraction, also exhibiting an increase in the radius of fine aerosols due to coagulation processes in a highly turbid environment. The spectral variation of the single-scattering albedo reveals enhanced dominance of moderately absorbing aerosols, while the aerosol properties, modification, and mixing atmospheric

  19. Variations of carbonaceous aerosols from open crop residue burning with transport and its implication to estimate their lifetimes

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

    Studying the correlations of carbonaceous aerosols (element carbon, EC, and organic carbon, OC) from open biomass burning helps to reduce uncertainties in emission inventories and provides necessary constraints for model simulations. In the present study, we measured apparent elemental carbon (ECa) and OC concentrations at the summit of Mount Tai (Mt. Tai) during intensive open crop residue burning (OCRB) episodes using a Sunset OCEC analyzer. In the fine particle mode, OC and ECa showed strong correlations (r > 0.9) with carbon monoxide (CO). Footprint analysis using the FLEXPART_WRF model indicated that OCRB in Central East China had a significant influence on ambient carbonaceous aerosol loadings at the summit of Mt. Tai. During campaign, ΔECa/ΔCO ratios of OCRB plumes were found to be 14.3 ± 1.0 ng m-3 ppbv at Mt. Tai. This ratio was twice larger than those for urban pollution in CEC, demonstrating that significant emissions of soot particles emitted from OCRB. ΔOC/ΔCO ratio of OCRB plumes was found to be 41.9 ± 2.6 ng m-3 ppbv averagely. The transport time of smoke particles was estimated using the FLEXPART_WRF tracer model by releasing particles from the ground layer inside geographical regions where large numbers of hotspots were detected by the MODIS sensor. The relationship between transport time and observed ΔECa/ΔCO and ΔOC/ΔCO ratios was fitted by an e-folding exponential function. Results showed that the loss rate of OC (normalized by CO) with transport was much quicker than that of ECa mass, and the corresponding lifetime of OC mass was estimated to be 28.0-44.2 h (1.2-1.8 days), much shorter than that 98.4-136.9 h (4.1-5.7 days) of ECa. Lifetime of ECa estimated for the OCRB events in CEC in the study was comparably lower than the values normally calculated by the transport models. Short lifetime of OC highlighted its vulnerability to cloud scavenging in the presence of water-soluble organic species from biomass combustion.

  20. Trans-Pacific transport and evolution of aerosols: evaluation of quasi-global WRF-Chem simulation with multiple observations

    NASA Astrophysics Data System (ADS)

    Hu, Zhiyuan; Zhao, Chun; Huang, Jianping; Leung, L. Ruby; Qian, Yun; Yu, Hongbin; Huang, Lei; Kalashnikova, Olga V.

    2016-05-01

    A fully coupled meteorology-chemistry model (WRF-Chem, the Weather Research and Forecasting model coupled with chemistry) has been configured to conduct quasi-global simulation for 5 years (2010-2014) and evaluated with multiple observation data sets for the first time. The evaluation focuses on the simulation over the trans-Pacific transport region using various reanalysis and observational data sets for meteorological fields and aerosol properties. The simulation generally captures the overall spatial and seasonal variability of satellite retrieved aerosol optical depth (AOD) and absorbing AOD (AAOD) over the Pacific that is determined by the outflow of pollutants and dust and the emissions of marine aerosols. The assessment of simulated extinction Ångström exponent (EAE) indicates that the model generally reproduces the variability of aerosol size distributions as seen by satellites. In addition, the vertical profile of aerosol extinction and its seasonality over the Pacific are also well simulated. The difference between the simulation and satellite retrievals can be mainly attributed to model biases in estimating marine aerosol emissions as well as the satellite sampling and retrieval uncertainties. Compared with the surface measurements over the western USA, the model reasonably simulates the observed magnitude and seasonality of dust, sulfate, and nitrate surface concentrations, but significantly underestimates the peak surface concentrations of carbonaceous aerosol likely due to model biases in the spatial and temporal variability of biomass burning emissions and secondary organic aerosol (SOA) production. A sensitivity simulation shows that the trans-Pacific transported dust, sulfate, and nitrate can make significant contribution to surface concentrations over the rural areas of the western USA, while the peaks of carbonaceous aerosol surface concentrations are dominated by the North American emissions. Both the retrievals and simulation show small

  1. Trans-Pacific transport and evolution of aerosols: Evaluation of quasi-global WRF-Chem simulation with multiple observations

    DOE PAGES

    Hu, Zhiyuan; Zhao, Chun; Huang, Jianping; Leung, L. Ruby; Qian, Yun; Yu, Hongbin; Huang, Lei; Kalashnikova, Olga V.

    2016-05-10

    A fully coupled meteorology-chemistry model (WRF-Chem, the Weather Research and Forecasting model coupled with chemistry) has been configured to conduct quasi-global simulation for 5 years (2010–2014) and evaluated with multiple observation data sets for the first time. The evaluation focuses on the simulation over the trans-Pacific transport region using various reanalysis and observational data sets for meteorological fields and aerosol properties. The simulation generally captures the overall spatial and seasonal variability of satellite retrieved aerosol optical depth (AOD) and absorbing AOD (AAOD) over the Pacific that is determined by the outflow of pollutants and dust and the emissions of marine aerosols.more » The assessment of simulated extinction Ångström exponent (EAE) indicates that the model generally reproduces the variability of aerosol size distributions as seen by satellites. In addition, the vertical profile of aerosol extinction and its seasonality over the Pacific are also well simulated. The difference between the simulation and satellite retrievals can be mainly attributed to model biases in estimating marine aerosol emissions as well as the satellite sampling and retrieval uncertainties. Compared with the surface measurements over the western USA, the model reasonably simulates the observed magnitude and seasonality of dust, sulfate, and nitrate surface concentrations, but significantly underestimates the peak surface concentrations of carbonaceous aerosol likely due to model biases in the spatial and temporal variability of biomass burning emissions and secondary organic aerosol (SOA) production. A sensitivity simulation shows that the trans-Pacific transported dust, sulfate, and nitrate can make significant contribution to surface concentrations over the rural areas of the western USA, while the peaks of carbonaceous aerosol surface concentrations are dominated by the North American emissions. Both the retrievals and simulation show

  2. Trans-Pacific transport and evolution of aerosols: evaluation of quasi-global WRF-Chem simulation with multiple observations

    SciTech Connect

    Hu, Zhiyuan; Zhao, Chun; Huang, Jianping; Leung, L. Ruby; Qian, Yun; Yu, Hongbin; Huang, Lei; Kalashnikova, Olga V.

    2016-01-01

    A fully coupled meteorology-chemistry model (WRF-Chem, the Weather Research and Forecasting model coupled with chemistry) has been configured to conduct quasi-global simulation for 5 years (2010–2014) and evaluated with multiple observation data sets for the first time. The evaluation focuses on the simulation over the trans-Pacific transport region using various reanalysis and observational data sets for meteorological fields and aerosol properties. The simulation generally captures the overall spatial and seasonal variability of satellite retrieved aerosol optical depth (AOD) and absorbing AOD (AAOD) over the Pacific that is determined by the outflow of pollutants and dust and the emissions of marine aerosols. The assessment of simulated extinction Ångström exponent (EAE) indicates that the model generally reproduces the variability of aerosol size distributions as seen by satellites. In addition, the vertical profile of aerosol extinction and its seasonality over the Pacific are also well simulated. The difference between the simulation and satellite retrievals can be mainly attributed to model biases in estimating marine aerosol emissions as well as the satellite sampling and retrieval uncertainties. Compared with the surface measurements over the western USA, the model reasonably simulates the observed magnitude and seasonality of dust, sulfate, and nitrate surface concentrations, but significantly underestimates the peak surface concentrations of carbonaceous aerosol likely due to model biases in the spatial and temporal variability of biomass burning emissions and secondary organic aerosol (SOA) production. A sensitivity simulation shows that the trans-Pacific transported dust, sulfate, and nitrate can make significant contribution to surface concentrations over the rural areas of the western USA, while the peaks of carbonaceous aerosol surface concentrations are dominated by the North American emissions. Both the retrievals and simulation show small

  3. Size distributions of aerosol and water-soluble ions in Nanjing during a crop residual burning event.

    PubMed

    Wang, Honglei; Zhu, Bin; Shen, Lijuan; Kang, Hanqing

    2012-01-01

    To investigate the impact on urban air pollution by crop residual burning outside Nanjing, aerosol concentration, pollution gas concentration, mass concentration, and water-soluble ion size distribution were observed during one event of November 4-9, 2010. Results show that the size distribution of aerosol concentration is bimodal on pollution days and normal days, with peak values at 60-70 and 200-300 nm, respectively. Aerosol concentration is 10(4) cm(-3) x nm(-1) on pollution days. The peak value of spectrum distribution of aerosol concentration on pollution days is 1.5-3.3 times higher than that on a normal day. Crop residual burning has a great impact on the concentration of fine particles. Diurnal variation of aerosol concentration is trimodal on pollution days and normal days, with peak values at 03:00, 09:00 and 19:00 local standard time. The first peak is impacted by meteorological elements, while the second and third peaks are due to human activities, such as rush hour traffic. Crop residual burning has the greatest impact on SO2 concentration, followed by NO2, O3 is hardly affected. The impact of crop residual burning on fine particles (< 2.1 microm) is larger than on coarse particles (> 2.1 microm), thus ion concentration in fine particles is higher than that in coarse particles. Crop residual burning leads to similar increase in all ion components, thus it has a small impact on the water-soluble ions order. Crop residual burning has a strong impact on the size distribution of K+, Cl-, Na+, and F- and has a weak impact on the size distributions of NH4+, Ca2+, NO3- and SO4(2-).

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  5. GUIDE TO CALCULATING TRANSPORT EFFICIENCY OF AEROSOLS IN OCCUPATIONAL AIR SAMPLING SYSTEMS

    SciTech Connect

    Hogue, M.; Hadlock, D.; Thompson, M.; Farfan, E.

    2013-11-12

    This report will present hand calculations for transport efficiency based on aspiration efficiency and particle deposition losses. Because the hand calculations become long and tedious, especially for lognormal distributions of aerosols, an R script (R 2011) will be provided for each element examined. Calculations are provided for the most common elements in a remote air sampling system, including a thin-walled probe in ambient air, straight tubing, bends and a sample housing. One popular alternative approach would be to put such calculations in a spreadsheet, a thorough version of which is shared by Paul Baron via the Aerocalc spreadsheet (Baron 2012). To provide greater transparency and to avoid common spreadsheet vulnerabilities to errors (Burns 2012), this report uses R. The particle size is based on the concept of activity median aerodynamic diameter (AMAD). The AMAD is a particle size in an aerosol where fifty percent of the activity in the aerosol is associated with particles of aerodynamic diameter greater than the AMAD. This concept allows for the simplification of transport efficiency calculations where all particles are treated as spheres with the density of water (1g cm-3). In reality, particle densities depend on the actual material involved. Particle geometries can be very complicated. Dynamic shape factors are provided by Hinds (Hinds 1999). Some example factors are: 1.00 for a sphere, 1.08 for a cube, 1.68 for a long cylinder (10 times as long as it is wide), 1.05 to 1.11 for bituminous coal, 1.57 for sand and 1.88 for talc. Revision 1 is made to correct an error in the original version of this report. The particle distributions are based on activity weighting of particles rather than based on the number of particles of each size. Therefore, the mass correction made in the original version is removed from the text and the calculations. Results affected by the change are updated.

  6. Non-spherical aerosol transport under oscillatory shear flows at low-Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Shachar Berman, Lihi; Delorme, Yann; Hofemeier, Philipp; Frankel, Steven; Sznitman, Josue

    2014-11-01

    Most airborne particles are intrinsically non-spherical. In particular, non-spherical particles with high aspect ratios, such as fibers, are acknowledged to be more hazardous than their spherical counterparts due to their ability to penetrate into deeper lung regions, causing serious pulmonary diseases. Not only do particle properties such as size, shape, and density have a major impact on particle transport, for non-spherical aerosols, their orientations also greatly influence particle trajectories due to modified lift and drag characteristics. Until present, however, most of our understanding of the dynamics of inhaled particles in the deep airways of the lungs has been limited to spherical particles only. In the present work, we seek to quantify through numerical simulations the transport of non-spherical airborne particles and their deposition under oscillatory shear flows at low Reynolds numbers, characteristic of acinar airways. Here, the Euler-Lagrangian model is used to solve the translational movement of a fiber, whereas the Eulerian rotational equations are introduced and solved to predict detailed unsteady fiber orientations. Overall, our efforts provide new insight into realistic dynamics of inhaled non-spherical aerosols under characteristic breathing motions.

  7. Characterization of Microphysical Properties of Saharan Dust Aerosols During Trans-Atlantic Transport

    NASA Astrophysics Data System (ADS)

    Roldan, L.; Morris, V. R.

    2005-12-01

    The NOAA Center in Atmospheric Sciences (NCAS) Trans-Atlantic Saharan Dust AERosol and Ocean Science Expedition (AEROSE) 2004 was a 27 day mission aboard the NOAA Ship Ronald H. Brown (RHB). The AEROSE mission took place during February 29th thru March 26th, departing from Barbados to the Canary Islands and ending in Puerto Rico. The cruise tracks for AEROSE 2004 coincided with one of the biggest dust storms to date for this season. One of the goals of the mission was to provide a set of critical measurements to characterize the impacts and microphysical evolution of Saharan dust aerosol during Trans-Atlantic transport. A Laser Particle Counter (LPC) was used to retrieve in-situ number density distribution. A Quartz Crystal Microbalance Cascade Impactor (QCM) was used to retrieve in-situ mass density distributions. The QCM also provides a sampling platform for post analysis to determine morphological properties and elemental chemical composition. The morphological properties were determined with the use of a Scanning Electron Microscope (SEM). The combination of the SEM with an Energy Dispersive X-Ray Microanalysis system provides the elemental composition details. I will present the evolution of the chemical elements as a function of size as they are transported. The elemental analysis has identified elements such as Fe, Al, Si, Zn, Ti, Co, S, and C all which are characteristics of Saharan dust origin.

  8. Trend of surface solar radiation over Asia simulated by aerosol transport-climate model

    NASA Astrophysics Data System (ADS)

    Takemura, T.; Ohmura, A.

    2009-12-01

    Long-term records of surface radiation measurements indicate a decrease in the solar radiation between the 1950s and 1980s (“global dimming”), then its recovery afterward (“global brightening”) at many locations all over the globe [Wild, 2009]. On the other hand, the global brightening is delayed over the Asian region [Ohmura, 2009]. It is suggested that these trends of the global dimming and brightening are strongly related with a change in aerosol loading in the atmosphere which affect the climate change through the direct, semi-direct, and indirect effects. In this study, causes of the trend of the surface solar radiation over Asia during last several decades are analyzed with an aerosol transport-climate model, SPRINTARS. SPRINTARS is coupled with MIROC which is a general circulation model (GCM) developed by Center for Climate System Research (CCSR)/University of Tokyo, National Institute for Environmental Studies (NIES), and Frontier Research Center for Global Change (FRCGC) [Takemura et al., 2000, 2002, 2005, 2009]. The horizontal and vertical resolutions are T106 (approximately 1.1° by 1.1°) and 56 layers, respectively. SPRINTARS includes the transport, radiation, cloud, and precipitation processes of all main tropospheric aerosols (black and organic carbons, sulfate, soil dust, and sea salt). The model treats not only the aerosol mass mixing ratios but also the cloud droplet and ice crystal number concentrations as prognostic variables, and the nucleation processes of cloud droplets and ice crystals depend on the number concentrations of each aerosol species. Changes in the cloud droplet and ice crystal number concentrations affect the cloud radiation and precipitation processes in the model. Historical emissions, that is consumption of fossil fuel and biofuel, biomass burning, aircraft emissions, and volcanic eruptions are prescribed from database provided by the Aerosol Model Intercomparison Project (AeroCom) and the latest IPCC inventories

  9. Long-Range Transport of Perchlorate Observed in the Atmospheric Aerosols Collected at Okinawa Island, Japan

    NASA Astrophysics Data System (ADS)

    Handa, D.; Okada, K.; Kuroki, Y.; Nakama, Y.; Nakajima, H.; Arakaki, T.; Tanahara, A.; Oomori, T.; Miyagi, T.; Kadena, H.; Ishizaki, T.; Nakama, F.

    2007-12-01

    aerosols collected at CHAAMS was probably transported from the Asian continent.

  10. Electron Microscopy Characterization of Aerosols Collected at Mauna Loa Observatory During Asian Dust Storm Event

    EPA Science Inventory

    Atmospheric aerosol particles have a significant influence on global climate due to their ability to absorb and scatter incoming solar radiation. Size, composition, and morphology affect a particle’s radiative properties and these can be characterized by electron microscopy. Lo...

  11. The Cloud-Aerosol Transport System (CATS): A New Earth Science Capability for ISS (Invited)

    NASA Astrophysics Data System (ADS)

    McGill, M. J.; Yorks, J. E.; Scott, S.; Kupchock, A.; Selmer, P.

    2013-12-01

    The Cloud-Aerosol Transport System (CATS) is a lidar remote sensing instrument developed for deployment to the International Space Station (ISS). The CATS lidar will provide range-resolved profile measurements of atmospheric aerosol and cloud distributions and properties. The CATS instrument uses a high repetition rate laser operating at three wavelengths (1064, 532, and 355 nm) to derive properties of cloud/aerosol layers including: layer height, layer thickness, backscatter, optical depth, extinction, and depolarization-based discrimination of particle type. The CATS mission was designed to capitalize on the Space Station's unique orbit and facilities to continue existing Earth Science data records, to provide observational data for use in forecast models, and to demonstrate new technologies for use in future missions. The CATS payload will be installed on the Japanese Experiment Module - Exposed Facility (JEM-EF). The payload is designed to operate on-orbit for at least six months, and up to three years. The payload is completed and currently scheduled for a mid-2014 launch. The ISS and, in particular, the JEM-EF, is an exciting new platform for spaceborne Earth observations. The ability to leverage existing aircraft instrument designs coupled with the lower cost possible for ISS external attached payloads permits rapid and cost effective development of spaceborne sensors. The CATS payload is based on existing instrumentation built and operated on the high-altitude NASA ER-2 aircraft. The payload is housed in a 1.5 m x 1 m x 0.8 m volume that attaches to the JEM-EF. The allowed volume limits the maximum size for the collecting telescope to 60 cm diameter. Figure 1 shows a schematic layout of the CATS payload, with the primary instrument components identified. Figure 2 is a photo of the completed payload. CATS payload cut-away view. Completed CATS payload assembly.

  12. Integrated Observation of Aerosol Plumes Transport and Impacts on the Air Quality Remote Sensing in the Northeast U.S.

    NASA Astrophysics Data System (ADS)

    Wu, Yonghua; Nazmi, Chowdhury; Han, Zaw; Li, Cuiya; Gross, Barry; Moshary, Fred

    2016-06-01

    In this paper, we present a cluster analysis of plume transport paths to New York City (NYC, 40.821ºN, 73.949ºW) for the 8-year period during 2006-2013. We also show cases of such aloft aerosol plumes intrusion and mixing into the boundary layer (PBL) and the impact on local air quality. Range-resolved monthly occurrence frequency and modification of local aerosol optical properties are presented. The NOAA-HYSPLIT cluster analysis indicates 6 main transport paths; and the optical properties (optical depth-AOD, Angstrom exponent-AE and single scatter albedo-SSA) of aerosol for each cluster are characterized. We further illustrate the impact of these aloft plumes on the satellite MODIS estimate of ground PM2.5 levels and observe that when the aloft plumes-layer AODs are filtered out using lidar, the correlation of MODIS AOD-PM2.5 can be much improved.

  13. Correcting transport errors during advection of aerosol and cloud moment sequences in eulerian models

    SciTech Connect

    McGraw R.

    2012-03-01

    Moment methods are finding increasing usage for simulations of particle population balance in box models and in more complex flows including two-phase flows. These highly efficient methods have nevertheless had little impact to date for multi-moment representation of aerosols and clouds in atmospheric models. There are evidently two reasons for this: First, atmospheric models, especially if the goal is to simulate climate, tend to be extremely complex and take many man-years to develop. Thus there is considerable inertia to the implementation of novel approaches. Second, and more fundamental, the nonlinear transport algorithms designed to reduce numerical diffusion during advection of various species (tracers) from cell to cell, in the typically coarse grid arrays of these models, can and occasionally do fail to preserve correlations between the moments. Other correlated tracers such as isotopic abundances, composition of aerosol mixtures, hydrometeor phase, etc., are subject to this same fate. In the case of moments, this loss of correlation can and occasionally does give rise to unphysical moment sets. When this happens the simulation can come to a halt. Following a brief description and review of moment methods, the goal of this paper is to present two new approaches that both test moment sequences for validity and correct them when they fail. The new approaches work on individual grid cells without requiring stored information from previous time-steps or neighboring cells.

  14. Study of aerosol transport through precipitation chemistry over Arabian Sea during winter and summer monsoons

    NASA Astrophysics Data System (ADS)

    Praveen, P. S.; Rao, P. S. P.; Safai, P. D.; Devara, P. C. S.; Chate, D. M.; Ali, K.; Momin, G. A.

    Precipitation samples over the Arabian Sea collected during Arabian Sea Monsoon Experiment (ARMEX) in 2002-2003 were examined for major water soluble components and acidity of aerosols during the period of winter and summer monsoon seasons. The pH of rain water was alkaline during summer monsoon and acidic during winter monsoon. Summer monsoon precipitation showed dominance of sea-salt components (˜90%) and significant amounts of non-sea salt (nss) Ca 2+ and SO 42-. Winter monsoon precipitation samples showed higher concentration of NO 3- and NH 4+ compared to that of summer monsoon, indicating more influence of anthropogenic sources. The rain water data is interpreted in terms of long-range transport and background pollution. In summer monsoon, air masses passing over the north African and Gulf continents which may be carrying nss components are advected towards the observational location. Also, prevailing strong southwesterly winds at surface level produced sea-salt aerosols which led to high sea-salt contribution in precipitation. While in winter monsoon, it was observed that, air masses coming from Asian region towards observational location carry more pollutants like NO 3-and nss SO 42- that acidify the precipitation.

  15. Transport and residence times of tropospheric aerosols inferred from a global three-dimensional simulation of Pb-210

    NASA Technical Reports Server (NTRS)

    Balkanski, Yves J.; Jacob, Daniel J.; Gardner, Geraldine M.; Graustein, William C.; Turekian, Karl K.

    1993-01-01

    A global three-dimensional model is used to investigate the transport and tropospheric residence time of Pb-210, an aerosol tracer produced in the atmosphere by radioactive decay of Rn-222 emitted from soils. The model uses meteorological input with 4 deg x 5 deg horizontal resolution and 4-hour temporal resolution from the Goddard Institute for Space Studies general circulation model (GCM). It computes aerosol scavenging by convective precipitation as part of the wet convective mass transport operator in order to capture the coupling between vertical transport and rainout. Scavenging in convective precipitation accounts for 74% of the global Pb-210 sink in the model; scavenging in large-scale precipitation accounts for 12%, and scavenging in dry deposition accounts for 14%. The model captures 63% of the variance of yearly mean Pb-210 concentrations measured at 85 sites around the world with negligible mean bias, lending support to the computation of aerosol scavenging. There are, however, a number of regional and seasonal discrepancies that reflect in part anomalies in GCM precipitation. Computed residence times with respect to deposition for Pb-210 aerosol in the tropospheric column are about 5 days at southern midlatitudes and 10-15 days in the tropics; values at northern midlatitudes vary from about 5 days in winter to 10 days in summer. The residence time of Pb-210 produced in the lowest 0.5 km of atmosphere is on average four times shorter than that of Pb-210 produced in the upper atmosphere. Both model and observations indicate a weaker decrease of Pb-210 concentrations between the continental mixed layer and the free troposphere than is observed for total aerosol concentrations; an explanation is that Rn-222 is transported to high altitudes in wet convective updrafts, while aerosols and soluble precursors of aerosols are scavenged by precipitation in the updrafts. Thus Pb-210 is not simply a tracer of aerosols produced in the continental boundary layer, but

  16. Development and application of a three-dimensional aerosol chemical transport model, PMCAMx

    NASA Astrophysics Data System (ADS)

    Gaydos, Timothy M.; Pinder, Rob; Koo, Bonyoung; Fahey, Kathleen M.; Yarwood, Gregory; Pandis, Spyros N.

    A three-dimensional chemical transport model (PMCAMx) is used to simulate PM mass and composition in the eastern United States for a July 2001 pollution episode. The performance of the model in this region is evaluated, taking advantage of the highly time and size-resolved PM and gas-phase data collected during the Pittsburgh Air Quality Study (PAQS). PMCAMx uses the framework of CAMx and detailed aerosol modules to simulate inorganic aerosol growth, aqueous-phase chemistry, secondary organic aerosol formation, nucleation, and coagulation. The model predictions are compared to hourly measurements of PM 2.5 mass and composition at Pittsburgh, as well as to measurements from the AIRS and IMPROVE networks. The performance of the model for the major PM 2.5 components (sulfate, ammonium, and organic carbon) is encouraging (fractional errors are in general smaller than 50%). Additional improvements are possible if the rainfall measurements are used instead of the meteorological model predictions. The modest errors in ammonium predictions and the lack of bias for the total (gas and particulate) ammonium suggest that the improved ammonia inventory used is reasonable. The significant errors in aerosol nitrate predictions are mainly due to difficulties in simulating the nighttime formation of nitric acid. The concentrations of elemental carbon (EC) in the urban areas are significantly overpredicted. This is a problem related to both the emission inventory but also the different EC measurement methods that have been used in the two measurement networks (AIRS and IMPROVE) and the actual development of the inventory. While the ability of the model to reproduce OC levels is encouraging, additional work is necessary to confirm that that this is due to the right reasons and not offsetting errors in the primary emissions and the secondary formation. The model performance against the semi-continuous measurements in Pittsburgh appears to be quite similar to its performance against

  17. Study of aerosol hygroscopic events over the Cabauw experimental site for atmospheric research (CESAR) using the multi-wavelength Raman lidar Caeli

    NASA Astrophysics Data System (ADS)

    Fernández, A. J.; Apituley, A.; Veselovskii, I.; Suvorina, A.; Henzing, J.; Pujadas, M.; Artíñano, B.

    2015-11-01

    This article presents a study of aerosol optical and microphysical properties under different relative humidity (RH) but well mixed layer conditions using optical and microphysical aerosol properties from multi-wavelength (MW) Raman lidar and in-situ aerosol observations collected at the Cabauw Experimental Site for Atmospheric Research (CESAR). Two hygroscopic events are described through 3 backscatter (β) and 2 extinction (α) coefficients which in turn provide intensive parameters such as the backscatter-related Ångström exponent (åβ) and the lidar ratio (LR). Along with it, profiles of RH were inferred from Raman lidar observations and therefore, as a result of varying humidity conditions, a shift on the aerosol optical properties can be described. Thus, it is observed that as RH increases, aerosols uptake water vapour, augment their size and consequently the åβ diminishes whereas the LR increases. The enhancement factor based on the backscatter coefficient at 532 nm, which characterizes the aerosol from hygroscopic standpoint, is also estimated. Finally, microphysical properties that are necessary for aerosol radiative forcing estimates - such as volume, effective radii, refractive index and size distribution, all vertically resolved - are retrieved using the inversion with regularization. Using this method, two hygroscopic events are described in detail.

  18. The Cloud-Aerosol Transport System (CATS): a technology demonstration on the International Space Station

    NASA Astrophysics Data System (ADS)

    McGill, Matthew J.; Yorks, John E.; Scott, V. S.; Kupchock, Andrew W.; Selmer, Patrick A.

    2015-09-01

    The Cloud-Aerosol Transport System (CATS) is a multi-wavelength lidar instrument developed to enhance Earth Science remote sensing capabilities from the International Space Station. The CATS project was chartered to be an experiment in all senses: science, technology, and management. As a low-cost project following a strict build-to-cost/ build-to-schedule philosophy, CATS is following a new management approach while also serving as a technology demonstration for future NASA missions. This presentation will highlight the CATS instrument and science objectives with emphasis on how the ISS platform enables the specific objectives of the payload. The development process used for CATS and a look at data being produced by the instrument will also be presented.

  19. Characterizing the Asian Tropopause Aerosol Layer (ATAL) Using Satellite Observations, Balloon Measurements and a Chemical Transport Model

    NASA Technical Reports Server (NTRS)

    Fairlie, T. D.; Vernier, J.-P.; Liu, H.; Deshler, T.; Natarajan, M.; Bedka, K.; Wegner, T.; Baker, N.; Gadhavi, H.; Ratnam, M. V.; Jayaraman, A.; Pandit, A.; Raj, A.; Kumar, H.; Kumar, S.; Singh, A.; Stenchikov, G.; Wienhold, F.; Bian, J.

    2016-01-01

    Satellite observations and numerical modeling studies have demonstrated that the Asian Summer Monsoon (ASM) provide a conduit for gas-phase pollutants in south Asia to reach the lower stratosphere. Now, observations from the CALIPSO satellite have revealed the Asian Tropopause Aerosol Layer (ATAL), a summertime accumulation of aerosols in the upper troposphere and lower stratosphere (UTLS), associated with the ASM anticyclone. The ATAL has potential implications for regional cloud properties, climate, and chemical processes in the UTLS. Here, we show in situ measurements from balloon-borne instruments, aircraft, and satellite observations, together with trajectory and chemical transport model (CTM) simulations to explore the origin, composition, physical, and optical properties of aerosols in the ATAL. In particular, we show balloon-data from our BATAL-2015 field campaign to India and Saudi Arabia in summer 2015, which includes in situ backscatter measurements from COBALD instruments, and the first observations of size and volatility of aerosols in the ATAL layer using optical particle counters (OPCs). Back trajectory calculations initialized from CALIPSO observations point to deep convection over North India as a principal source of ATAL aerosols. Available aircraft observations suggest significant sulfur and carbonaceous components to the ATAL, which is supported by simulations using the GEOS-Chem CTM. Source elimination studies conducted with the GEOS-Chem indicate that ATAL aerosols originate primary from south Asian sources, in contrast with some earlier studies.

  20. Characterization of Florida red tide aerosol and the temporal profile of aerosol concentration.

    PubMed

    Cheng, Yung Sung; Zhou, Yue; Pierce, Richard H; Henry, Mike; Baden, Daniel G

    2010-05-01

    Red tide aerosols containing aerosolized brevetoxins are produced during the red tide bloom and transported by wind to coastal areas of Florida. This study reports the characterization of Florida red tide aerosols in human volunteer studies, in which an asthma cohort spent 1h on Siesta Beach (Sarasota, Florida) during aerosolized red tide events and non-exposure periods. Aerosol concentrations, brevetoxin levels, and particle size distribution were measured. Hourly filter samples were taken and analyzed for brevetoxin and NaCl concentrations. In addition, the aerosol mass concentration was monitored in real time. The results indicated that during a non-exposure period in October 2004, no brevetoxin was detected in the water, resulting in non-detectable levels of brevetoxin in the aerosol. In March 2005, the time-averaged concentrations of brevetoxins in water samples were moderate, in the range of 5-10 microg/L, and the corresponding brevetoxin level of Florida red tide aerosol ranged between 21 and 39 ng/m(3). The temporal profiles of red tide aerosol concentration in terms of mass, NaCl, and brevetoxin were in good agreement, indicating that NaCl and brevetoxins are components of the red tide aerosol. By continuously monitoring the marine aerosol and wind direction at Siesta Beach, we observed that the marine aerosol concentration varied as the wind direction changed. The temporal profile of the Florida red tide aerosol during a sampling period could be explained generally with the variation of wind direction.

  1. Characterization of Florida red tide aerosol and the temporal profile of aerosol concentration

    PubMed Central

    Cheng, Yung Sung; Zhou, Yue; Pierce, Richard H.; Henry, Mike; Baden, Daniel G.

    2009-01-01

    Red tide aerosols containing aerosolized brevetoxins are produced during the red tide bloom and transported by wind to coastal areas of Florida. This study reports the characterization of Florida red tide aerosols in human volunteer studies, in which an asthma cohort spent 1 h on Siesta Beach (Sarasota, Florida) during aerosolized red tide events and non-exposure periods. Aerosol concentrations, brevetoxin levels, and particle size distribution were measured. Hourly filter samples were taken and analyzed for brevetoxin and NaCl concentrations. In addition, the aerosol mass concentration was monitored in real time. The results indicated that during a non-exposure period in October 2004, no brevetoxin was detected in the water, resulting in non-detectable levels of brevetoxin in the aerosol. In March 2005, the time-averaged concentrations of brevetoxins in water samples were moderate, in the range of 5–10 μg/L, and the corresponding brevetoxin level of Florida red tide aerosol ranged between 21 and 39 ng/m3. The temporal profiles of red tide aerosol concentration in terms of mass, NaCl, and brevetoxin were in good agreement, indicating that NaCl and brevetoxins are components of the red tide aerosol. By continuously monitoring the marine aerosol and wind direction at Siesta Beach, we observed that the marine aerosol concentration varied as the wind direction changed. The temporal profile of the Florida red tide aerosol during a sampling period could be explained generally with the variation of wind direction. PMID:19879288

  2. Characterizing the influence of anthropogenic emissions and transport variability on sulfate aerosol concentrations at Mauna Loa Observatory

    NASA Astrophysics Data System (ADS)

    Potter, Lauren E.

    Sulfate aerosol in the atmosphere has substantial impacts on human health and environmental quality. Most notably, atmospheric sulfate has the potential to modify the earth's climate system through both direct and indirect radiative forcing mechanisms (Meehl et al., 2007). Emissions of sulfur dioxide, the primary precursor of sulfate aerosol, are now globally dominated by anthropogenic sources as a result of widespread fossil fuel combustion. Economic development in Asian countries since 1990 has contributed considerably to atmospheric sulfur loading, particularly China, which currently emits approximately 1/3 of global anthropogenic SO2 (Klimont et al., 2013). Observational and modeling studies have confirmed that anthropogenic pollutants from Asian sources can be transported long distances with important implications for future air quality and global climate change. Located in the remote Pacific Ocean (19.54°N, 155.58°W) at an elevation of 3.4 kilometers above sea level, Mauna Loa Observatory (MLO) is an ideal measurement site for ground-based, free tropospheric observations and is well situated to experience influence from springtime Asian outflow. This study makes use of a 14-year data set of aerosol ionic composition, obtained at MLO by the University of Hawaii at Manoa. Daily filter samples of total aerosol concentrations were made during nighttime downslope (free-tropospheric) transport conditions, from 1995 to 2008, and were analyzed for aerosol-phase concentrations of the following species: nitrate (NO3-), sulfate (SO42-), methanesulfonate (MSA), chloride (Cl-), oxalate, sodium (Na+), ammonium (NH 4+), potassium (K+), magnesium (Mg 2+), and calcium (Ca2+). An understanding of the factors controlling seasonal and interannual variations in aerosol speciation and concentrations at this site is complicated by the relatively short lifetimes of aerosols, compared with greenhouse gases which have also been sampled over long time periods at MLO. Aerosol filter

  3. Chinese mineral dust and anthropogenic aerosol inter-continental transport: a Greenland perspective

    NASA Astrophysics Data System (ADS)

    Bory, A.; Abouchami, W.; Galer, S.; Svensson, A.; Biscaye, P.

    2012-04-01

    Impurities contained in snow and ice layers in Greenland provide a record of the history of atmospheric dustiness and pollution in the Northern Hemisphere. The source of the particles deposited onto the ice cap may be investigated using specific intrinsic tracers. Provenance discrimination may then provide valuable constraints for the validation of atmospheric transport models as well as for the monitoring of natural and anthropogenic aerosols emissions at a global scale. Clay mineralogy combined with the strontium and neodymium isotope composition of the insoluble particles extracted from recent snow deposits at NorthGRIP (75.1°N, 042.3°W), for instance, enabled us to demonstrate that the Taklimakan desert of North-western China was the main source of mineral dust reaching central Greenland at present [Bory et al., EPSL, 2002 ; GRL, 2003a]. Here we report the lead isotopic signature of these snow-pit samples, covering the 1989-1995 and 1998-2001 time periods. Unradiogenic lead isotopic composition of our Greenland samples, compared to Asian dust isotopic fingerprints, implies that most of the insoluble lead reaching the ice cap is of anthropogenic origin. Lead isotopes reveal likely contributions from European/Canadian and, to a lesser extent, US sources, as well as a marked overprinted signature typical of Chinese anthropogenic lead sources. The relative contribution of the latter appears to have been increasing steadily over the last decade of the 20th century. Quantitative estimates suggest that, in addition to providing most of the dust, China may have already become the most important supplier of anthropogenic lead deposited in Greenland by the turn of the 20th to the 21st century. The close timing between dust and anthropogenic particles deposition onto the ice cap provides new insights for our understanding of Chinese aerosols transport to Greenland.

  4. Impact of aerosols on radiation during a heavy haze event in Beijing

    NASA Astrophysics Data System (ADS)

    Yan, Wang; Zhengqiang, Li; Ying, Zhang; Qiang, Wang; Jianzhong, Ma

    2014-03-01

    In order to understand the influence of anthropogenic aerosols on radiation in the urban boundary layer, we measured atmospheric aerosol mass concentrations (PM10 and PM2.5), integrated solar radiation, wind and temperature at different layers of a 325-m iron tower. A typical heavy haze process occurring during the period of October 2004 was analyzed. It is observed that the inversion layer and the weak wind was the most important factor causing the accumulation of pollutants. The results show that the PM10 concentrations under polluted day conditions is about 84 times (537.1μgm-3) higher than those on clear weather conditions (6.4μgm-3). The difference in the solar radiation between 2m and 280m became smaller (93.07 Wm-2 to 16.07 Wm-2) when pollution turned heavy, while the attenuations rate changed large (16.76% to 20.96%)

  5. Metals and Rare Earth Elements in polar aerosol as specific markers of natural and anthropogenic aerosol sources areas and atmospheric transport processes

    NASA Astrophysics Data System (ADS)

    Giardi, Fabio; Becagli, Silvia; Caiazzo, Laura; Cappelletti, David; Grotti, Marco; Malandrino, Mery; Salzano, Roberto; Severi, Mirko; Traversi, Rita; Udisti, Roberto

    2016-04-01

    Metals and Rare Earth Elements (REEs) in the aerosol have conservative properties from the formation to the deposition and can be useful to identify and quantify their natural and anthropic sources and to study the atmospheric transport processes. In spite of their importance relatively little is known about metals and especially REEs in the Artic atmosphere due to their low concentration in such environment. The present work reports the first attempt to determine and interpret the behaviour of metals and REEs in polar aerosol at high temporal resolution. Daily PM10 samples of arctic atmospheric particulate were collected on Teflon filters, during six spring-summer campaigns, since 2010, in the laboratory of Gruvebadet in Ny Ålesund (78°56' N, 11°56' E, Svalbard Islands, Norway). Chemical analyses were carried out through Inductively Coupled Plasma Mass Spectrometer provided with a desolvation nebulizer inlet system, allowing to reduce isobaric interferences and thus to quantify trace and ultra-trace metals in very low concentration in the Arctic aerosol samples. The results are useful in order to study sources areas, transport processes and depositional effects of natural and anthropic atmospheric particulate reaching the Arctic from southern industrialized areas; moreover, the observed seasonal trends give information about the different impact of natural and anthropic emissions driven by phenomena such as the Arctic Haze and the melting of the snow. In particular Rare Earth Elements (often in the ppt range) can be considered as soil's fingerprints of the particulate source areas and their determination, together with air-mass backtrajectory analysis, allow to identify dust source areas for the arctic mineral aerosol.

  6. Characteristics of the long-range transport dust events in Chengdu, Southwest China

    NASA Astrophysics Data System (ADS)

    Chen, Yuan; Luo, Bin; Xie, Shao-dong

    2015-12-01

    Chengdu is an inland megacity in the Sichuan Basin, where dust influence remained an open question. During a one-year haze campaign, two dust events were identified in March 2013, indicating that desert dust can be transported to Chengdu and impacted local air quality strongly. The suggested low SO2/PM10, NO2/PM10 and PM2.5/PM10 ratios of 0.15, 0.27 and 0.40 could be used as immediate indicators for dust days. On typical dust day of March 12, PM10 was as high as 359.1 μg m-3, and crustal matter contributed 80.5% to total PM2.5 mass (106.6 μg m-3). Enrichment factors of most elements have decreased due to the dilution effect except for Ca and Mg. The dust was mainly from western and northern dust regions in China, including the "Northerly Mongolia Path", "Western Desert Path" and "Northwestern Desert Path". Due to the obstruction of Qinghai-Tibet Plateau on the west, the dust air to Chengdu was mostly from the northeastward direction after passing over Qinling Mountain. Moreover, the air experienced obvious elevation from its source regions driven by the cold front synoptic pattern. The spatial distribution of high AOD (Aerosol Optical Depth) values over 1.2 but low Ångström exponent of 0.5-0.6 around Chengdu verified the coarse pollution patterns. However, the dust pollution was not serious in nearby Chongqing and Guizhou and exhibited weak regional feature, a result different from those in Beijing and Shanghai.

  7. Top-Down Inversion of Aerosol Emissions through Adjoint Integration of Satellite Radiance and GEOS-Chem Chemical Transport Model

    NASA Astrophysics Data System (ADS)

    Xu, X.; Wang, J.; Henze, D. K.; Qu, W.; Kopacz, M.

    2012-12-01

    The knowledge of aerosol emissions from both natural and anthropogenic sources are needed to study the impacts of tropospheric aerosol on atmospheric composition, climate, and human health, but large uncertainties persist in quantifying the aerosol sources with the current bottom-up methods. This study presents a new top-down approach that spatially constrains the amount of aerosol emissions from satellite (MODIS) observed reflectance with the adjoint of a chemistry transport model (GEOS-Chem). We apply this technique with a one-month case study (April 2008) over the East Asia. The bottom-up estimated sulfate-nitrate-ammonium precursors, such as sulfur dioxide (SO2), ammonia (NH3), and nitrogen oxides (NOx), all from INTEX-B 2006 inventory, emissions of black carbon (BC), organic carbon (OC) from Bond-2007 inventory, and mineral dust simulated from DEAD dust mobilization scheme, are spatially optimized from the GEOS-Chem model and its adjoint constrained by the aerosol optical depth (AOD) that are derived from MODIS reflectance with the GEOS-Chem aerosol single scattering properties. The adjoint inverse modeling for the study period yields notable decreases in anthropogenic aerosol emissions over China: 436 Gg (33.5%) for SO2, 378 Gg (34.5%) for NH3, 319 (18.8%) for NOx, 10 Gg (9.1%) for BC, and 30 Gg (15.0%) for OC. The total amount of the mineral dust emission is reduced by 56.4% from the DEAD mobilization module which simulates dust production of 19020 Gg. Sub-regional adjustments are significant and directions of changes are spatially different. The model simulation with optimized aerosol emissions shows much better agreement with independent observations from sun-spectrophotometer observed AOD from AERONET, MISR (Multi-angle Imaging SpectroRadiometer) AOD, OMI (Ozone Monitoring Instrument) NO2 and SO2 columns, and surface aerosol concentrations measured over both anthropogenic pollution and dust source regions. Assuming the used bottom-up anthropogenic

  8. Aerosol Types using Passive Remote Sensing: Global Distribution, Consistency Check, Total-Column Investigation and Translation into Composition Derived from Climate and Chemical Transport Model

    NASA Astrophysics Data System (ADS)

    Kacenelenbogen, M. S.; Dawson, K. W.; Johnson, M. S.; Burton, S. P.; Redemann, J.; Hasekamp, O. P.; Hair, J. W.; Ferrare, R. A.; Butler, C. F.; Holben, B. N.; Beyersdorf, A. J.; Ziemba, L. D.; Froyd, K. D.; Dibb, J. E.; Shingler, T.; Sorooshian, A.; Jimenez, J. L.; Campuzano Jost, P.; Jacob, D. J.

    2015-12-01

    To improve the predictions of aerosol composition in chemical transport models (CTMs) and global climate models (GCMs), we have developed an aerosol classification algorithm (called Specified Clustering and Mahalanobis Classification, SCMC) that assigns an aerosol type to multi-parameter retrievals by spaceborne, airborne or ground based passive remote sensing instruments [Russell et al., 2014]. The aerosol types identified by our scheme are pure dust, polluted dust, urban-industrial/developed economy, urban-industrial/developing economy, dark biomass smoke, light biomass smoke and pure marine. We apply the SCMC method to two different total-column datasets of aerosol optical properties: inversions from the ground-based AErosol RObotic NETwork (AERONET) and retrievals from the space-borne POLDER (Polarization and Directionality of Earth's Reflectances) instrument. The POLDER retrievals that we use differ from the standard POLDER retrievals [Deuzé et al., 2001] as they make full use of multi-angle, multispectral polarimetric data [Hasekamp et al., 2011]. We analyze agreement in the aerosol types inferred from both AERONET and POLDER globally. Then, we investigate how our total-column "effective" SCMC aerosol types relate to different aerosol types within the column (i.e. either a mixture of different types within one layer in the vertical or the stacking of different aerosol types within the vertical column). For that, we compare AERONET-SCMC aerosol types to collocated NASA LaRC HSRL vertically resolved aerosol types [Burton et al., 2012] during the SEAC4RS and DISCOVER-AQ airborne field experiments, mostly over Texas in Aug-Sept 2013. Finally, in order to evaluate the GEOS-Chem CTM aerosol types, we translate each of our SCMC aerosol type into a unique distribution of GEOS-Chem aerosol composition (e.g. biomass burning, dust, sulfate, sea salt). We bridge the gap between remote sensing and model-inferred aerosol types by using multiple years of collocated AERONET

  9. Discrete-event simulation of nuclear-waste transport in geologic sites subject to disruptive events. Final report

    SciTech Connect

    Aggarwal, S.; Ryland, S.; Peck, R.

    1980-06-19

    This report outlines a methodology to study the effects of disruptive events on nuclear waste material in stable geologic sites. The methodology is based upon developing a discrete events model that can be simulated on the computer. This methodology allows a natural development of simulation models that use computer resources in an efficient manner. Accurate modeling in this area depends in large part upon accurate modeling of ion transport behavior in the storage media. Unfortunately, developments in this area are not at a stage where there is any consensus on proper models for such transport. Consequently, our work is directed primarily towards showing how disruptive events can be properly incorporated in such a model, rather than as a predictive tool at this stage. When and if proper geologic parameters can be determined, then it would be possible to use this as a predictive model. Assumptions and their bases are discussed, and the mathematical and computer model are described.

  10. GENERATION, TRANSPORT AND DEPOSITION OF TUNGSTEN-OXIDE AEROSOLS AT 1000 C IN FLOWING AIR-STEAM MIXTURES.

    SciTech Connect

    GREENE,G.A.; FINFROCK,C.C.

    2001-10-01

    Experiments were conducted to measure the rates of oxidation and vaporization of pure tungsten rods in flowing air, steam and air-steam mixtures in laminar flow. Also measured were the downstream transport of tungsten-oxide condensation aerosols and their region of deposition, including plateout in the superheated flow tube, rainout in the condenser and ambient discharge which was collected on an array of sub-micron aerosol filters. The nominal conditions of the tests, with the exception of the first two tests, were tungsten temperatures of 1000 C, gas mixture temperatures of 200 C and wall temperatures of 150 C to 200 C. It was observed that the tungsten oxidation rates were greatest in all air and least in all steam, generally decreasing non-linearly with increasing steam mole fraction. The tungsten oxidation rates in all air were more than five times greater than the tungsten oxidation rates in all steam. The tungsten vaporization rate was zero in all air and increased with increasing steam mole fraction. The vaporization rate became maximum at a steam mole fraction of 0.85 and decreased thereafter as the steam mole fraction was increased to unity. The tungsten-oxide was transported downstream as condensation aerosols, initially flowing upwards from the tungsten rod through an 18-inch long, one-inch diameter quartz tube, around a 3.5-inch radius, 90{sup o} bend and laterally through a 24-inch horizontal run. The entire length of the quartz glass flow path was heated by electrical resistance clamshell heaters whose temperatures were individually controlled and measured. The tungsten-oxide plateout in the quartz tube was collected, nearly all of which was deposited at the end of the heated zone near the entrance to the condenser which was cold. The tungsten-oxide which rained out in the condenser as the steam condensed was collected with the condensate and weighed after being dried. The aerosol smoke which escaped the condenser was collected on the sub

  11. A High-Spatial-Resolution, Localized MODIS Aerosol Optical Depth Product for Use in Air Quality Exposure Assessment During Large Wildfire Smoke Events

    NASA Astrophysics Data System (ADS)

    McCarthy, M. C.; Raffuse, S. M.; DeWinter, J. L.; Craig, K. J.; Jumbam, L. K.; Fruin, S.; Lurmann, F.

    2011-12-01

    Aerosol optical depth (AOD) has potential use for determining the intra-urban variability of airborne particulate matter exposure during wildfire events; however, the standard Moderate Resolution Imaging Spectroradiometer (MODIS) AOD products have limitations for this application. Specifically, the 10x10 km resolution is too coarse for intra-urban population exposure assessments, the assumed aerosol optical properties are not representative of biomass burning aerosol, and the cloud masking algorithm misinterprets heavy smoke as clouds. We developed a localized MODIS AOD product at 1.5 and 2.5 km resolutions and tested the performance in northern California during the 2008 wildfires. The localized product's algorithm uses local biomass burning aerosol optical properties, local surface reflectance data, and a relaxed cloud filter. During the 2008 season, persistent heavy smoke was produced over northern California and the San Joaquin Valley for over two months. As California is both highly populated and covered with a relatively dense network of ground-based aerosol monitoring stations, this event provided an excellent opportunity to develop the AOD product and test its ability to predict aerosol concentrations on the ground to assess population exposure. We will present our methodology and discuss its potential for air quality and public health applications.

  12. Vertical Structure of Aerosols and Mineral Dust Transport Over the Bay of Bengal Using Multi-Satellite Observations.

    NASA Astrophysics Data System (ADS)

    Naduparambil Bharathan, L.

    2015-12-01

    Bay-of-Bengal (BoB), a small oceanic region Eat to Indian land mass, surrounded by heavily inhabited land masses, experiences different types of air-masses in different seasons of contrasting wind patterns, which makes it a region of large heterogeneity in the context of regional climate forcing due to atmospheric aerosols. Heterogeneity of aerosol system over the Bay of Bengal is mainly determined by three distinct source regions, which are east coast of India/central India, China/east Asia and Arabian region. Continental aerosols transported through higher elevations over BoB lead to significant impacts in regional climate by modifying the vertical thermal structure of the atmosphere and associated circulation dynamics. The study aims at a comprehensive understanding on the spatial and temporal heterogeneity of elevated aerosol over the BoB using the observations of Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aboard Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). Being capable of short wave scattering and long wave absorption, mineral dust aerosols can affects the energetics of the atmosphere over any region.Owing to its influence on Indian monsoon rainfall and regional climate, the study aims to comprehend on the spatial and seasonal variation of mineral dust transport over the Bay of Bengal. vertical distribution of the dust extinction coefficient over the Bay of Bengal for all seasons, is derived, using a dust separation scheme that uses the depolarization measurements, a priori information on lidar ratio of dust, depolarization ratio of dust and that of non-dust aerosols. Being highly non-spherical, mineral dust significantly depolarize the radiation and possess distinct range of depolarization ratio. This property of dust is made use to identify and quantify dust over the study region. Seasonal variation of dust fraction over the Bay of Bengal is estimated seperately from CALIPSO back scattering coefficients

  13. Long-range transport of anthropogenic aerosols to the National Oceanic and Atmospheric Administration baseline station at Mauna Loa Observatory, Hawaii

    NASA Astrophysics Data System (ADS)

    Perry, Kevin D.; Cahill, Thomas A.; Schnell, Russell C.; Harris, Joyce M.

    1999-08-01

    Size-segregated measurements of aerosol mass and composition are used to determine the composition and seasonal variations of natural and anthropogenic aerosols at Mauna Loa Observatory (MLO) from 1993 through 1996. Although the springtime transport of Asian dust to MLO is a well-documented phenomenon, this study shows that fine anthropogenic aerosols, including sulfur, black carbon, and enriched trace metals such as As, Cu, Pb, and Zn, are also routinely transported to MLO each spring. It is estimated that at least one third of the sulfate measured at MLO during the spring is anthropogenic. In addition, indirect measurements indicate that the organic aerosol concentrations are often comparable to the sulfate concentrations. This study also combines size- and time-resolved aerosol composition measurements with isentropic, backward air-mass trajectories and gas measurements of 222Rn, CH4, CO, and CO2 to identify some potential source regions of the anthropogenic aerosols. Three types of long-range transport episodes are identified: (1) anthropogenic aerosols mixed with Asian dust, (2) Asian pollution with relatively small amounts of soil dust, and (3) biomass burning emissions from North America. This study shows that anthropogenic aerosols and gases can be efficiently transported to MLO from both Asia and North America during the spring.

  14. Potential feedback between aerosols and meteorological conditions in a heavy pollution event over the Tibetan Plateau and Indo-Gangetic Plain

    NASA Astrophysics Data System (ADS)

    Yang, Junhua; Duan, Keqin; Kang, Shichang; Shi, Peihong; Ji, Zhenming

    2016-06-01

    A regional climate model, WRF-Chem, was used to investigate the feedback between aerosols and meteorological conditions in the planetary boundary layer (PBL) over the Tibetan Plateau (TP) and Indo-Gangetic Plain (IGP). The numerical experiments (15-km horizontal resolution) with and without the aerosol effects are driven by reanalysis of data for 1-31 March 2009, when a heavy pollution event (13-19 March) occurred. The results showed that the model captured the spatial and temporal meteorological conditions and aerosol optical characteristics during the heavy pollution days. Aerosols induced cooling at the surface and warming in the middle troposphere due to their radiative effects, and resulted in a more stable PBL over the IGP. Aerosol-induced 2-m relative humidity (RH) was increased. The stable PBL likely led to the surface PM2.5 concentration increase of up to 21 μg m-3 (15 %) over the IGP. For the TP, the atmospheric profile did not drastically change due to fewer radiative effects of aerosols in the PBL compared with those over the IGP. The aerosol-induced RH decreased due to cloud albedo and cloud lifetime effect, and led to a reduction in surface PM2.5 concentration of up to 17 μg m-3 (13 %). These results suggest a negative and positive feedback over the TP and IGP, respectively, between aerosol concentrations and changes of aerosol-induced meteorological conditions. Similar positive feedbacks have been observed in other heavily polluted regions (e.g., the North China Plain). The results have implications for the study of air pollution on weather and environment over the TP and IGP.

  15. Potential feedback between aerosols and meteorological conditions in a heavy pollution event over the Tibetan Plateau and Indo-Gangetic Plain

    NASA Astrophysics Data System (ADS)

    Yang, Junhua; Duan, Keqin; Kang, Shichang; Ji, Zhenming; Shi, Peihong

    2016-04-01

    A regional climate model WRF-Chem was used to investigate the feedback between aerosols and meteorological conditions in atmospheric boundary layer over the Tibetan Plateau (TP) and Indo-Gangetic Plain (IGP). The numerical experiments with and without the aerosol effects are driven by reanalysis from March 1-31, 2009, when a heavy pollution event (March 13-19) occurred. Results showed that the model can capture the spatial and temporal meteorological conditions and aerosols optical characteristics during the heavy pollution days. Aerosols induce cooling at the surface and warming in the middle of troposphere due to their radiative effects, and result in the atmospheric boundary layer (ABL) trend to more stable over the IGP. Aerosols-induced 2-meter relative humidity (RH2) is increased, which superposes the stable ABL lead to the surface PM2.5 concentration increases by up to 21 ug m-3 (15%) over the IGP. For the TP, the atmospheric profile does not change too much due to the fewer aerosols' radiative effects in the ABL comparing to those over the IGP. The aerosols-induced RH2 decreases because of the cloud albedo and cloud lifetime effect and leads to the surface PM2.5 concentration reduce up to 17 ug m-3 (13%). It is implicated that a negative/positive feedback between aerosols concentration and changes of aerosol-induced meteorological conditions over the TP/IGP, which is like/unlike the situations in other heavy polluted regions (e.g., the North China Plain). The results have a potential implication of air pollution on weather and environment over the TP and IGP.

  16. Number-size distribution of aerosol particles and new particle formation events in tropical and subtropical Pacific Oceans

    NASA Astrophysics Data System (ADS)

    Ueda, S.; Miura, K.; Kawata, R.; Furutani, H.; Uematsu, M.; Omori, Y.; Tanimoto, H.

    2016-10-01

    Number-size distributions of aerosol particles with diameters of 10-500 nm in the marine boundary layer were observed continually onboard the R/V Hakuho Maru over the equatorial and subtropical North Pacific and South Pacific during December 2011-March 2012. Number-size distributions over each area were parameterized using a sum of up to three lognormal functions. Bi-modal size distributions with peak diameters at 30-80 nm (Aitken mode) and 100-200 nm (accumulation mode) were observed frequently. Larger peak diameters of Aitken and accumulation modes were observed over the eastern equator, where 5-day backward trajectories showed that the air masses had derived from high-chlorophyll oceanic regions without precipitation. Smaller peak diameters and low concentrations were often observed over the North Pacific. The trajectories show that such air mass originated from oceanic regions with less chlorophyll, exhibiting high precipitation frequency. New particle formation (NPF) events have often been observed over the mid-latitude eastern South Pacific with a low condensation sink (CS) and some dimethyl sulfide, although none was observed over the equator, where CS was higher. The lesser CS condition at NPF events was mostly correlated with local precipitation or precipitation along the trajectories within 1 day. These results suggest that differences of the number-size distribution and occasions of NPF events among sea areas most closely accord with precipitation along the trajectories.

  17. Long-range transport and mixing of aerosol sources during the 2013 North American biomass burning episode: analysis of multiple lidar observations in the western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Ancellet, Gerard; Pelon, Jacques; Totems, Julien; Chazette, Patrick; Bazureau, Ariane; Sicard, Michaël; Di Iorio, Tatiana; Dulac, Francois; Mallet, Marc

    2016-04-01

    Long-range transport of biomass burning (BB) aerosols between North America and the Mediterranean region took place in June 2013. A large number of ground-based and airborne lidar measurements were deployed in the western Mediterranean during the Chemistry-AeRosol Mediterranean EXperiment (ChArMEx) intensive observation period. A detailed analysis of the potential North American aerosol sources is conducted including the assessment of their transport to Europe using forward simulations of the FLEXPART Lagrangian particle dispersion model initialized using satellite observations by MODIS and CALIOP. The three-dimensional structure of the aerosol distribution in the ChArMEx domain observed by the ground-based lidars (Minorca, Barcelona and Lampedusa), a Falcon-20 aircraft flight and three CALIOP tracks, agrees very well with the model simulation of the three major sources considered in this work: Canadian and Colorado fires, a dust storm from western US and the contribution of Saharan dust streamers advected from the North Atlantic trade wind region into the westerlies region. Four aerosol types were identified using the optical properties of the observed aerosol layers (aerosol depolarization ratio, lidar ratio) and the transport model analysis of the contribution of each aerosol source: (i) pure BB layer, (ii) weakly dusty BB, (iii) significant mixture of BB and dust transported from the trade wind region, and (iv) the outflow of Saharan dust by the subtropical jet and not mixed with BB aerosol. The contribution of the Canadian fires is the major aerosol source during this episode while mixing of dust and BB is only significant at an altitude above 5 km. The mixing corresponds to a 20-30 % dust contribution in the total aerosol backscatter. The comparison with the MODIS aerosol optical depth horizontal distribution during this episode over the western Mediterranean Sea shows that the Canadian fire contributions were as large as the direct northward dust outflow

  18. Impact of the March 2009 dust event in Saudi Arabia on aerosol optical properties, meteorological parameters, sky temperature and emissivity

    NASA Astrophysics Data System (ADS)

    Maghrabi, A.; Alharbi, B.; Tapper, N.

    2011-04-01

    On 10th March 2009 a widespread and severe dust storm event that lasted several hours struck Riyadh, and represented one of the most intense dust storms experienced in Saudi Arabia in the last two decades. This short-lived storm caused widespread and heavy dust deposition, zero visibility and total airport shutdown, as well as extensive damage to buildings, vehicles, power poles and trees across the city of Riyadh. Changes in Meteorological parameters, aerosol optical depth (AOD), Angstrom exponent α, infrared (IR) sky temperature and atmospheric emissivity were investigated before, during, and after the storm. The analysis showed significant changes in all of the above parameters due to this event. Shortly after the storm arrived, air pressure rapidly increased by 4 hPa, temperature decreased by 6 °C, relative humidly increased from 10% to 30%, the wind direction became northerly and the wind speed increased to a maximum of 30 m s -1. AOD at 550 nm increased from 0.396 to 1.71. The Angstrom exponent α rapidly decreased from 0.192 to -0.078. The mean AOD at 550 nm on the day of the storm was 0.953 higher than during the previous clear day, while α was -0.049 in comparison with 0.323 during the previous day. Theoretical simulations using SMART software showed remarkable changes in both spectral and broadband solar radiation components. The global and direct radiation components decreased by 42% and 68%, respectively, and the diffuse components increased by 44% in comparison with the previous clear day. IR sky temperatures and sky emissivity increased by 24 °C and 0.3, respectively, 2 h after the arrival of the storm. The effect of aerosol loading by the storm on IR atmospheric emission was investigated using MODTRAN software. It was found that the effect of aerosols caused an increase of the atmospheric emission in the atmospheric window (8-14 μm) such that the window emissions resembled those of a blackbody and the atmospheric window was almost closed.

  19. Impact of Emissions and Long-Range Transport on Multi-Decadal Aerosol Trends: Implications for Air Quality and Climate

    NASA Technical Reports Server (NTRS)

    Chin, Mian

    2012-01-01

    We present a global model analysis of the impact of long-range transport and anthropogenic emissions on the aerosol trends in the major pollution regions in the northern hemisphere and in the Arctic in the past three decades. We will use the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model to analyze the multi-spatial and temporal scale data, including observations from Terra, Aqua, and CALIPSO satellites and from the long-term surface monitoring stations. We will analyze the source attribution (SA) and source-receptor (SR) relationships in North America, Europe, East Asia, South Asia, and the Arctic at the surface and free troposphere and establish the quantitative linkages between emissions from different source regions. We will discuss the implications for regional air quality and climate change.

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

    PubMed

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

    2009-07-01

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

  1. Synergy between Secondary Organic Aerosols and Long Range Transport of Polycyclic Aromatic Hydrocarbons

    SciTech Connect

    Zelenyuk, Alla; Imre, D.; Beranek, Josef; Abramson, Evan H.; Wilson, Jacqueline M.; Shrivastava, ManishKumar B.

    2012-10-25

    Polycyclic aromatic hydrocarbons (PAHs) known for their harmful health effects undergo long-range transport (LRT) when adsorbed on and/or absorbed in atmospheric particles. The association between atmospheric particles, PAHs, and their LRT has been the subject of many studies, yet remains poorly understood. Current models assume PAHs instantaneously attain reversible gas-particle equilibrium. In this paradigm, during LRT, as gas-phase PAHs concentrations are depleted due to oxidation and dilution, particle-bound PAHs rapidly evaporate to re-establish equilibrium, leading to severe underpredictions of LRT potential of particle-bound PAHs. Here we present a new, experimentally based picture, in which the PAHs become trapped inside highly viscous quasi-solid secondary organic aerosol (SOA) particles during particle formation, and thus prevented from evaporation, and shielded from oxidation. In contrast, surface-adsorbed PAHs rapidly evaporate, leaving no trace behind. We find synergetic effects between PAHs and SOA, in that the presence of PAHs inside SOA particles drastically slows SOA evaporation to the point that it can be ignored, and the highly viscous SOA prevents PAHs evaporation assuring efficient LRT. The data show that the assumptions of instantaneous reversible gas-particle equilibrium for PAHs and for SOA are fundamentally flawed, providing explanation for the persistent discrepancy between observed and predicted particle-bound PAHs.

  2. Bulk, surface, and gas-phase limited water transport in aerosol.

    PubMed

    Davies, James F; Haddrell, Allen E; Miles, Rachael E H; Bull, Craig R; Reid, Jonathan P

    2012-11-15

    The influence of solute species on mass transfer to and from aqueous aerosol droplets is investigated using an electrodynamic balance coupled with light scattering techniques. In particular, we explore the limitations imposed on water evaporation by slow bulk phase diffusion and by the formation of surface organic films. Measurements of evaporation from ionic salt solutions, specifically sodium chloride and ammonium sulfate, are compared with predictions from an analytical model framework, highlighting the uncertainties associated with quantifying gas diffusional transport. The influence of low solubility organic acids on mass transfer is reported and compared to both model predictions and previous work. The limiting value of the evaporation coefficient that can be resolved by this approach, when uncertainties in key thermophysical quantities are accounted for, is estimated. The limitation of slow bulk phase diffusion on the evaporation rate is investigated for gel and glass states formed during the evaporation of magnesium sulfate and sucrose droplets, respectively. Finally, the effect of surfactants on evaporation has been probed, with soluble surfactants (such as sodium dodecyl sulfate) leading to little or no retardation of evaporation through slowing of surface layer kinetics. PMID:23095147

  3. The Explicit-Cloud Parameterized-Pollutant Hybrid Approach for Aerosol-Cloud Interactions in Multiscale Modelling Framework Models: Tracer Transport Results

    SciTech Connect

    Gustafson, William I.; Berg, Larry K.; Easter, Richard C.; Ghan, Steven J.

    2008-05-30

    All estimates of aerosol indirect effects on the global energy balance have either completely neglected the influence of aerosol on convective clouds or treated the influence in a highly parameterized manner. Embedding cloud-resolving models (CRMs) within each grid cell of a global model provides a multiscale modelling framework for treating both the influence of aerosols on convective as well as stratiform clouds and the influence of all clouds on the aerosol, but treating the interactions explicitly by simulating all aerosol processes in the CRM would be computationally prohibitive. An alternate approach is to use horizontal statistics (e.g., cloud mass flux, cloud fraction, and precipitation) from the CRM simulation to drive a single-column parameterization of cloud effects on the aerosol and then use the aerosol profile to simulate aerosol effects on clouds within the CRM. Here we test this concept for vertical transport by clouds, using a CRM with tracer transport simulated explicitly to serve as a benchmark. We show that this parameterization, driven by the CRM’s cloud mass fluxes, reproduces the tracer transport by the CRM significantly better than a single column model that uses a conventional convective cloud parameterization.

  4. First implementation of secondary inorganic aerosols in the MOCAGE version R2.15.0 chemistry transport model

    NASA Astrophysics Data System (ADS)

    Guth, J.; Josse, B.; Marécal, V.; Joly, M.; Hamer, P.

    2016-01-01

    In this study we develop a secondary inorganic aerosol (SIA) module for the MOCAGE chemistry transport model developed at CNRM. The aim is to have a module suitable for running at different model resolutions and for operational applications with reasonable computing times. Based on the ISORROPIA II thermodynamic equilibrium module, the new version of the model is presented and evaluated at both the global and regional scales. The results show high concentrations of secondary inorganic aerosols in the most polluted regions: Europe, Asia and the eastern part of North America. Asia shows higher sulfate concentrations than other regions thanks to emission reductions in Europe and North America. Using two simulations, one with and the other without secondary inorganic aerosol formation, the global model outputs are compared to previous studies, to MODIS AOD retrievals, and also to in situ measurements from the HTAP database. The model shows a better agreement with MODIS AOD retrievals in all geographical regions after introducing the new SIA scheme. It also provides a good statistical agreement with in situ measurements of secondary inorganic aerosol composition: sulfate, nitrate and ammonium. In addition, the simulation with SIA generally gives a better agreement with observations for secondary inorganic aerosol precursors (nitric acid, sulfur dioxide, ammonia), in particular with a reduction of the modified normalized mean bias (MNMB). At the regional scale, over Europe, the model simulation with SIA is compared to the in situ measurements from the EMEP database and shows a good agreement with secondary inorganic aerosol composition. The results at the regional scale are consistent with those obtained from the global simulations. The AIRBASE database was used to compare the model to regulated air quality pollutants: particulate matter, ozone and nitrogen dioxide concentrations. Introduction of the SIA in MOCAGE provides a reduction in the PM2.5 MNMB of 0.44 on a

  5. An evaluation of the impact of aerosol particles on weather forecasts from a biomass burning aerosol event over the Midwestern United States: observational-based analysis of surface temperature

    NASA Astrophysics Data System (ADS)

    Zhang, Jianglong; Reid, Jeffrey S.; Christensen, Matthew; Benedetti, Angela

    2016-05-01

    A major continental-scale biomass burning smoke event from 28-30 June 2015, spanning central Canada through the eastern seaboard of the United States, resulted in unforecasted drops in daytime high surface temperatures on the order of 2-5 °C in the upper Midwest. This event, with strong smoke gradients and largely cloud-free conditions, provides a natural laboratory to study how aerosol radiative effects may influence numerical weather prediction (NWP) forecast outcomes. Here, we describe the nature of this smoke event and evaluate the differences in observed near-surface air temperatures between Bismarck (clear) and Grand Forks (overcast smoke), to evaluate to what degree solar radiation forcing from a smoke plume introduces daytime surface cooling, and how this affects model bias in forecasts and analyses. For this event, mid-visible (550 nm) smoke aerosol optical thickness (AOT, τ) reached values above 5. A direct surface cooling efficiency of -1.5 °C per unit AOT (at 550 nm, τ550) was found. A further analysis of European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers for Environmental Prediction (NCEP), United Kingdom Meteorological Office (UKMO) near-surface air temperature forecasts for up to 54 h as a function of Moderate Resolution Imaging Spectroradiometer (MODIS) Dark Target AOT data across more than 400 surface stations, also indicated the presence of the daytime aerosol direct cooling effect, but suggested a smaller aerosol direct surface cooling efficiency with magnitude on the order of -0.25 to -1.0 °C per unit τ550. In addition, using observations from the surface stations, uncertainties in near-surface air temperatures from ECMWF, NCEP, and UKMO model runs are estimated. This study further suggests that significant daily changes in τ550 above 1, at which the smoke-aerosol-induced direct surface cooling effect could be comparable in magnitude with model uncertainties, are rare events on a global scale. Thus, incorporating

  6. The Airborne Cloud-Aerosol Transport System. Part I; Overview and Description of the Instrument and Retrival Algorithms

    NASA Technical Reports Server (NTRS)

    Yorks, John E.; Mcgill, Matthew J.; Scott, V. Stanley; Kupchock, Andrew; Wake, Shane; Hlavka, Dennis; Hart, William; Selmer, Patrick

    2014-01-01

    The Airborne Cloud-Aerosol Transport System (ACATS) is a multi-channel Doppler lidar system recently developed at NASA Goddard Space Flight Center (GSFC). A unique aspect of the multi-channel Doppler lidar concept such as ACATS is that it is also, by its very nature, a high spectral resolution lidar (HSRL). Both the particulate and molecular scattered signal can be directly and unambiguously measured, allowing for direct retrievals of particulate extinction. ACATS is therefore capable of simultaneously resolving the backscatterextinction properties and motion of a particle from a high altitude aircraft. ACATS has flown on the NASA ER-2 during test flights over California in June 2012 and science flights during the Wallops Airborne Vegetation Experiment (WAVE) in September 2012. This paper provides an overview of the ACATS method and instrument design, describes the ACATS retrieval algorithms for cloud and aerosol properties, and demonstrates the data products that will be derived from the ACATS data using initial results from the WAVE project. The HSRL retrieval algorithms developed for ACATS have direct application to future spaceborne missions such as the Cloud-Aerosol Transport System (CATS) to be installed on the International Space Station (ISS). Furthermore, the direct extinction and particle wind velocity retrieved from the ACATS data can be used for science applications such 27 as dust or smoke transport and convective outflow in anvil cirrus clouds.

  7. Scattering and absorption properties of near-surface aerosol over Gangetic-Himalayan region: the role of boundary-layer dynamics and long-range transport

    NASA Astrophysics Data System (ADS)

    Dumka, U. C.; Kaskaoutis, D. G.; Srivastava, M. K.; Devara, P. C. S.

    2015-02-01

    Light scattering and absorption properties of atmospheric aerosols are of vital importance for evaluating their types, sources and radiative forcing. This is of particular interest over the Gangetic-Himalayan (GH) region due to uplift of aerosol from the plains to the Himalayan range, causing serious effects on atmospheric heating, glaciology and monsoon circulation. In this respect, the Ganges Valley Aerosol Experiment (GVAX) was initiated in Nainital from June 2011 to March 2012 with the aim of examining the aerosol properties, source regions, uplift mechanisms and aerosol-radiation-cloud interactions. The present study examines the temporal (diurnal, monthly, seasonal) evolution of scattering (σtransport (LRT) in aerosol evolution via the Atmospheric Radiation Measurement Mobile Facility. The analysis is separated for particles <10 μm and <1 μm in diameter in order to examine the influence of particle size on optical properties. The σsp and σap exhibit a pronounced seasonal variation between the monsoon low and post-monsoon (November) high, while the scattering wavelength exponent exhibits higher values during the monsoon, in contrast to the absorption Ångström exponent which maximizes in December-March. The elevated-background measuring site provides the advantage of examining the LRT of natural and anthropogenic aerosols from the IGP and southwest Asia and the role of BLD in the aerosol lifting processes. The results reveal higher aerosol concentrations at noontime along with an increase in mixing height, suggesting influence from IGP. The locally emitted aerosols present higher wavelength dependence of the absorption in October-March compared to the rather well-mixed and aged transported aerosols. Monsoon rainfall and seasonally changing air masses contribute to the alteration of the

  8. Transport of dusts from East Asian and non-East Asian sources to Hong Kong during dust storm related events 1996-2007

    NASA Astrophysics Data System (ADS)

    Lee, Y. C.; Yang, Xun; Wenig, Mark

    2010-09-01

    Over a twelve year period from 1996 to 2007, 76 dust storm related events (as days) in Hong Kong were selected for study, based on Aluminium and Calcium concentrations in PM 10. Four of the 76 events reach episodic levels with exceedances of the Hong Kong air quality standards. The purpose of the study is to identify and characterize dust sources impacting Hong Kong. Global distribution of aerosols in NASA's daily aerosol index images from TOMS and OMI, are compared to plots generated by NRL(US)'s Navy Aerosol Analysis and Prediction System. Possible source areas are assigned by computing air parcel backward trajectories to Hong Kong using the NOAA HYSPLIT model. PM 10 and elemental data are analyzed for crustal mass concentrations and element mass ratios. Our analysis reveals that 73 out of the 76 dust events (96%) involve non-East Asian sources-the Thar, Central/West Asian, Arabian and Sahara deserts (Saharan influence is found in 63 events), which are previously not known to affect Hong Kong. The Gobi desert is the most frequent origin of dust, affecting 68 dust events while the Taklamakan desert impacts only 30 of the dust events. The impact of the Gobi desert in March and December is apparently associated with the northeast monsoon in East Asia. Our results also show a seasonal pattern in dust impact from both East Asian and more remote sources, with a maximum in March. Dust event occurrences are conspicuously absent from summer. Dust transport to Hong Kong is commonly associated with the passage of frontal low-pressure systems. The coarse size fraction of PM 10 concentrations were, as indicated by Al, Ca and Fe concentrations, about 4-8 times higher during dust events. The mean Ca/Al ratios of sources involving the Taklamakan desert are notably higher than those for non-East Asian sources owing to a higher Ca content of most of the East Asian deserts. The Fe/Al ratios follow a similar trend. Contributions from the desert sources are grossly estimated where

  9. Chemical characterization of submicron aerosol and particle growth events at a national background site (3295 m a.s.l.) on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Du, W.; Sun, Y. L.; Xu, Y. S.; Jiang, Q.; Wang, Q. Q.; Yang, W.; Wang, F.; Bai, Z. P.; Zhao, X. D.; Yang, Y. C.

    2015-09-01

    Atmospheric aerosols exert highly uncertain impacts on radiative forcing and also have detrimental effects on human health. While aerosol particles are widely characterized in megacities in China, aerosol composition, sources and particle growth in rural areas in the Tibetan Plateau remain less understood. Here we present the results from an autumn study that was conducted from 5 September to 15 October 2013 at a national background monitoring station (3295 m a.s.l.) in the Tibetan Plateau. The submicron aerosol composition and particle number size distributions were measured in situ with an Aerodyne Aerosol Chemical Speciation Monitor (ACSM) and a Scanning Mobility Particle Sizer (SMPS). The average mass concentration of submicron aerosol (PM1) is 11.4 μg m-3 (range: 1.0-78.4 μg m-3) for the entire study, which is much lower than observed at urban and rural sites in eastern China. Organics dominated PM1, accounting for 43 % on average, followed by sulfate (28 %) and ammonium (11 %). Positive Matrix Factorization analysis of ACSM organic aerosol (OA) mass spectra identified an oxygenated OA (OOA) and a biomass burning OA (BBOA). The OOA dominated OA composition, accounting for 85 % on average, 17 % of which was inferred from aged BBOA. The BBOA contributed a considerable fraction of OA (15 %) due to the burning of cow dung and straw in September. New particle formation and growth events were frequently observed (80 % of time) throughout the study. The average particle growth rate is 2.0 nm h-1 (range: 0.8-3.2 nm h-1). By linking the evolution of particle number size distribution to aerosol composition, we found an elevated contribution of organics during particle growth periods and also a positive relationship between the growth rate and the fraction of OOA in OA, which potentially indicates an important role of organics in particle growth in the Tibetan Plateau.

  10. Long range transport and mixing of aerosol sources during the 2013 North American biomass burning episode: analysis of multiple lidar observations in the Western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Ancellet, G.; Pelon, J.; Totems, J.; Chazette, P.; Bazureau, A.; Sicard, M.; Di Iorio, T.; Dulac, F.; Mallet, M.

    2015-11-01

    Long range transport of biomass burning (BB) aerosols between North America and the Mediterranean region took place in June 2013. A large number of ground based and airborne lidar measurements were deployed in the Western Mediterranean during the Chemistry-AeRosol Mediterranean EXperiment (ChArMEx) intensive observation period. A detailed analysis of the potential North American aerosol sources is conducted including the assessment of their transport to Europe using forward simulations of the FLEXPART Lagrangian particle dispersion model initialized using satellite observations by MODIS and CALIOP. The three dimensional structure of the aerosol distribution in the ChArMEx domain observed by the ground-based lidars (Menorca, Barcelona and Lampedusa), a Falcon-20 aircraft flight and three CALIOP tracks, agree very well with the model simulation of the three major sources considered in this work: Canadian and Colorado fires, a dust storm from Western US and the contribution of Saharan dust streamers advected from the North Atlantic trade wind region into the Westerlies region. Four aerosol types were identified using the optical properties of the observed aerosol layers (aerosol depolarization ratio, lidar ratio) and the transport model analysis of the contribution of each aerosol source: (I) pure BB layer, (II) weakly dusty BB, (III) significant mixture of BB and dust transported from the trade wind region (IV) the outflow of Saharan dust by the subtropical jet and not mixed with BB aerosol. The contribution of the Canadian fires is the major aerosol source during this episode while mixing of dust and BB is only significant at altitude above 5 km. The mixing corresponds to a 20-30 % dust contribution in the total aerosol backscatter. The comparison with the MODIS AOD horizontal distribution during this episode over the Western Mediterranean sea shows that the Canadian fires contribution were as large as the direct northward dust outflow from Sahara.

  11. Features, Events, and Processes in UZ Flow and Transport

    SciTech Connect

    P. Persoff

    2004-11-06

    The evaluation of impacts of potential volcanic eruptions on populations and facilities far in the future may involve detailed volcanological studies that differ from traditional hazards analyses. The proximity of Quaternary volcanoes to a proposed repository for disposal of the USA's high-level radioactive waste at Yucca Mountain, Nevada, has required in-depth study of probability and consequences of basaltic igneous activity. Because of the underground nature of the repository, evaluation of the potential effects of dike intrusion and interaction with the waste packages stored in underground tunnels (dnfts) as well as effects of eruption and ash dispersal have been important. These studies include analyses of dike propagation, dike-drift intersection, flow of magma into dnfts, heat and volcanic gas migration, atmospheric dispersal of tephra, and redistribution of waste-contaminated tephra by surficial processes. Unlike traditional volcanic hazards studies that focus on impacts on housing, transportation, communications, etc. (to name a small subset), the igneous consequences studies at Yucca Mountain have focused on evaluation of igneous impacts on nuclear waste packages and implications for enhanced radioactive dose on a hypothetical future ({le} 10000 yrs) local population. Potential exposure pathways include groundwater (affected by in-situ degradation of waste packages by igneous heat and corrosion) and inhalation, ingestion, and external exposure due to deposition and redistribution of waste-contaminated tephra.

  12. Aerosol transport simulations in indoor and outdoor environments using computational fluid dynamics (CFD)

    NASA Astrophysics Data System (ADS)

    Landazuri, Andrea C.

    This dissertation focuses on aerosol transport modeling in occupational environments and mining sites in Arizona using computational fluid dynamics (CFD). The impacts of human exposure in both environments are explored with the emphasis on turbulence, wind speed, wind direction and particle sizes. Final emissions simulations involved the digitalization process of available elevation contour plots of one of the mining sites to account for realistic topographical features. The digital elevation map (DEM) of one of the sites was imported to COMSOL MULTIPHYSICSRTM for subsequent turbulence and particle simulations. Simulation results that include realistic topography show considerable deviations of wind direction. Inter-element correlation results using metal and metalloid size resolved concentration data using a Micro-Orifice Uniform Deposit Impactor (MOUDI) under given wind speeds and directions provided guidance on groups of metals that coexist throughout mining activities. Groups between Fe-Mg, Cr-Fe, Al-Sc, Sc-Fe, and Mg-Al are strongly correlated for unrestricted wind directions and speeds, suggesting that the source may be of soil origin (e.g. ore and tailings); also, groups of elements where Cu is present, in the coarse fraction range, may come from mechanical action mining activities and saltation phenomenon. Besides, MOUDI data under low wind speeds (<2 m/s) and at night showed a strong correlation for 1 mum particles between the groups: Sc-Be-Mg, Cr-Al, Cu-Mn, Cd-Pb-Be, Cd-Cr, Cu-Pb, Pb-Cd, As-Cd-Pb. The As-Cd-Pb correlates strongly in almost all ranges of particle sizes. When restricted low wind speeds were imposed more groups of elements are evident and this may be justified with the fact that at lower speeds particles are more likely to settle. When linking these results with CFD simulations and Pb-isotope results it is concluded that the source of elements found in association with Pb in the fine fraction come from the ore that is subsequently processed

  13. Mixing state of particles with secondary species by single particle aerosol mass spectrometer in an atmospheric pollution event

    NASA Astrophysics Data System (ADS)

    Xu, Lingling; Chen, Jinsheng

    2016-04-01

    Single particle aerosol mass spectrometer (SPAMS) was used to characterize size distribution, chemical composition, and mixing state of particles in an atmospheric pollution event during 20 Oct. - 5 Nov., 2015 in Xiamen, Southeast China. A total of 533,012 particle mass spectra were obtained and clustered into six groups, comprising of industry metal (4.5%), dust particles (2.6%), carbonaceous species (70.7%), K-Rich particles (20.7%), seasalt (0.6%) and other particles (0.9%). Carbonaceous species were further divided into EC (70.6%), OC (28.5%), and mixed ECOC (0.9%). There were 61.7%, 58.3%, 4.0%, and 14.6% of particles internally mixed with sulfate, nitrate, ammonium and C2H3O, respectively, indicating that these particles had undergone significant aging processing. Sulfate was preferentially mixed with carbonaceous particles, while nitrate tended to mix with metal-containing and dust particles. Compared to clear days, the fractions of EC-, metal- and dust particles remarkably increased, while the fraction of OC-containing particles decreased in pollution days. The mixing state of particles, excepted for OC-containing particles with secondary species was much stronger in pollution days than that in clear days, which revealed the significant influence of secondary particles in atmospheric pollution. The different activity of OC-containing particles might be related to their much smaller aerodynamic diameter. These results could improve our understanding of aerosol characteristics and could be helpful to further investigate the atmospheric process of particles.

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

    NASA Astrophysics Data System (ADS)

    Papayannis, Alexandros; Argyrouli, Athina; Müller, Detlef; Tsaknakis, Georgios; Kokkalis, Panayotis; Binietoglou, Ioannis; Kazadzis, Stelios; Solomos, Stavros; Amiridis, Vassilis

    2016-06-01

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

  15. Impacts of Long-Range Transport of Metals from East Asia in Bulk Aerosols Collected at the Okinawa Archipelago, Japan

    NASA Astrophysics Data System (ADS)

    A, Sotaro; S, Yuka; I, Moriaki; N, Fumiya; H, Daishi; A, Takemitsu; T, Akira

    2010-05-01

    Economy of East Asia has been growing rapidly, and atmospheric aerosols discharged from this region have been transported to Japan. Okinawa island is situated approximately 1500 km south of Tokyo, Japan, 2000 km southeast of Beijing, China, and 1000 km of south Korea. Its location in Asian is well suited for studying long-range transport of air pollutants in East Asia because maritime air mass prevails during summer, while continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background and can be compared with continental air mass which has been affected by anthropogenic activities. Therefore, Okinawa region is suitable area for studying impacts of air pollutants from East Asia. We simultaneously collected bulk aerosol samples by using the same type of high volume air samplers at Cape Hedo Atmospheric Aerosol Monitoring Station (CHAAMS, Okinawa island), Kume island (ca. 160 km south-west of CHAAMS), and Minami-Daitou island (ca. 320 km south-east of CHAAMS). We determined the concentrations of acid-digested metals using atomic absorption spectrometer and inductively-coupled plasma mass spectrometry (ICP-MS). We report and discuss spatial and temporal distribution of metals in the bulk atmospheric aerosols collected at CHAAMS, Kume island and Minami-Daitou island during June, 2008 to June 2009. We also determined 'background' concentration of metals in Okinawa archipelago. We then compare each chemical component among CHAAMS, Kume island and Minami-Daitou island to elucidate the influence of the transport processes and distances from Asian continent on metal concentrations.

  16. Aerosols and past environments: A global investigation into cave aerosol identification, distribution, and contribution to speleothem geochemistry

    NASA Astrophysics Data System (ADS)

    Dredge, J. A.; Fairchild, I. J.; Harrison, R. M.; Woodhead, J. D.; Hellstrom, J.; Mattey, D.

    2013-12-01

    A new sector of interest is developing within cave science regarding the influence of aerosols on the cave environment and the potential speleothem palaeoenvironmental aerosol record which may be preserved. This paper presents the results from a global collaboration project which explored all aspects of aerosols in the cave environment. Cave aerosol identification, introduction and distribution Cave aerosol multivariable environmental monitoring projects were carried out in the UK, Spain, Austria and Australia. Results demonstrate that cave ventilation is the predominant control on the introduction and distribution of aerosols throughout the cave environment (Dredge et al., 2013). Consequently, aerosol transportation processes vary as a result of seasonal ventilation changes and cave morphological features. Cave aerosol contribution to speleothem geochemistry Aerosol contributions to speleothem geochemistry were determined by comparing monitored aerosol deposition to speleothem trace element data. Significant aerosol contribution scenarios were identified as: hiatus events, high aerosol flux situations and secondary microbial concentration processes. Modelling indicates that a >99.9% reduction in drip water flow rates is required to reduce trace element supply quantities to equal that of aerosol supply (Dredge et al., 2013). Aerosol palaeoclimate and palaeoenvironmental records Aerosol contributions and the ability to utilise aerosol records in speleothem are investigated in samples from Gibraltar and Australia. Long range dust sources and past atmospheric circulation over several glacial cycles is studied through Sr isotope analysis of a Flowstone core from Gibraltar. Results of organic fire proxy analysis from Australian speleothem samples indicate an aerosol deposition forest fire record. In addition to primary fire deposition, secondary biological feedbacks and subsequent bioaccumulation processes in the cave environment are explored by microbial analysis

  17. Influence of weather on emergency transport events coded as stroke: population-based study in Japan

    NASA Astrophysics Data System (ADS)

    Ohshige, Kenji; Hori, Yuta; Tochikubo, Osamu; Sugiyama, Mitsugi

    2006-05-01

    Studying the relation between incidence of stroke and weather is difficult because it requires large-scale community-based data collection. Despite the lack of strong evidence that weather conditions influence stroke incidence, many clinicians feel that meteorological conditions influence the onset of stroke. This study examined whether emergency events related to stroke are influenced by meteorological factors and was based on computerized records of emergency medical transport services in a Japanese city during the period January 1992-December 2003. A total of 53,585 patients transported for an event coded as stroke were analyzed in relation to meteorological factors such as temperature, humidity, and barometric pressure. Poisson regression analysis was applied to clarify the influence of daily meteorological conditions on the daily incidence of emergency transport due to events coded as stroke. Ordinary least squares regression analysis was used to evaluate the influence of weather, defined as the combination of meteorological parameters, on the occurrence of emergency transport due to events coded as stroke. Daily mean ambient temperature and daily mean relative humidity showed a statistically significant negative effect on the incidence of the emergency transport events for both men and women ( P<0.001). Daily mean barometric pressure was not significantly related to these events. The occurrence of a holiday was negatively related to the incidence ( P<0.001). Dry weather and cool weather were likely to shift the circadian curve of the incidence upward. Thus, occurrence of emergency transport due to events coded as stroke is likely to be associated with weather conditions.

  18. Influence of weather on emergency transport events coded as stroke: population-based study in Japan.

    PubMed

    Ohshige, Kenji; Hori, Yuta; Tochikubo, Osamu; Sugiyama, Mitsugi

    2006-05-01

    Studying the relation between incidence of stroke and weather is difficult because it requires large-scale community-based data collection. Despite the lack of strong evidence that weather conditions influence stroke incidence, many clinicians feel that meteorological conditions influence the onset of stroke. This study examined whether emergency events related to stroke are influenced by meteorological factors and was based on computerized records of emergency medical transport services in a Japanese city during the period January 1992-December 2003. A total of 53,585 patients transported for an event coded as stroke were analyzed in relation to meteorological factors such as temperature, humidity, and barometric pressure. Poisson regression analysis was applied to clarify the influence of daily meteorological conditions on the daily incidence of emergency transport due to events coded as stroke. Ordinary least squares regression analysis was used to evaluate the influence of weather, defined as the combination of meteorological parameters, on the occurrence of emergency transport due to events coded as stroke. Daily mean ambient temperature and daily mean relative humidity showed a statistically significant negative effect on the incidence of the emergency transport events for both men and women (P<0.001). Daily mean barometric pressure was not significantly related to these events. The occurrence of a holiday was negatively related to the incidence (P<0.001). Dry weather and cool weather were likely to shift the circadian curve of the incidence upward. Thus, occurrence of emergency transport due to events coded as stroke is likely to be associated with weather conditions.

  19. Development of algorithms for using satellite meteorological data sets to study global transport of stratospheric aerosols and ozone

    NASA Technical Reports Server (NTRS)

    Want, P. H.; Deepak, A.

    1985-01-01

    The utilization of stratospheric aerosol and ozone measurements obtained from the NASA developed SAM II and SAGE satellite instruments were investigated for their global scale transports. The stratospheric aerosols showed that during the stratospheric warming of the winter 1978 to 1979, the distribution of the zonal mean aerosol extinction ratio in the northern high latitude exhibited distinct changes. Dynamic processes might have played an important role in maintenance role in maintenance of this zonal mean distribution. As to the stratospheric ozone, large poleward ozone transports are shown to occur in the altitude region from 24 km to 38 km near 55N during this warming. This altitude region is shown to be a transition region of the phase relationship between ozone and temperature waves from an in-phase one above 38 km. It is shown that the ozone solar heating in the upper stratosphere might lead to enhancement of the damping rate of the planetary waves due to infrared radiation alone in agreement with theoretical analyses and an earlier observational study.

  20. Effects of long-range aerosol transport on the microphysical properties of low-level liquid clouds in the Arctic

    NASA Astrophysics Data System (ADS)

    Coopman, Quentin; Garrett, Timothy J.; Riedi, Jérôme; Eckhardt, Sabine; Stohl, Andreas

    2016-04-01

    The properties of low-level liquid clouds in the Arctic can be altered by long-range pollution transport to the region. Satellite, tracer transport model, and meteorological data sets are used here to determine a net aerosol-cloud interaction (ACInet) parameter that expresses the ratio of relative changes in cloud microphysical properties to relative variations in pollution concentrations while accounting for dry or wet scavenging of aerosols en route to the Arctic. For a period between 2008 and 2010, ACInet is calculated as a function of the cloud liquid water path, temperature, altitude, specific humidity, and lower tropospheric stability. For all data, ACInet averages 0.12 ± 0.02 for cloud-droplet effective radius and 0.16 ± 0.02 for cloud optical depth. It increases with specific humidity and lower tropospheric stability and is highest when pollution concentrations are low. Carefully controlling for meteorological conditions we find that the liquid water path of arctic clouds does not respond strongly to aerosols within pollution plumes. Or, not stratifying the data according to meteorological state can lead to artificially exaggerated calculations of the magnitude of the impacts of pollution on arctic clouds.

  1. Characterization of aerosolized bacteria and fungi from desert dust events in Mali, West Africa

    USGS Publications Warehouse

    Kellogg, C.A.; Griffin, Dale W.; Garrison, V.H.; Peak, K.K.; Royall, N.; Smith, R.R.; Shinn, E.A.

    2004-01-01

    Millions of metric tons of African desert dust blow across the Atlantic Ocean each year, blanketing the Caribbean and southeastern United States. Previous work in the Caribbean has shown that atmospheric samples collected during dust events contain living microbes, including plant and opportunistic human pathogens. To better understand the potential downwind public health and ecosystem effects of the dust microbes, it is important to characterize the source population. We describe 19 genera of bacteria and 3 genera of fungi isolated from air samples collected in Mali, a known source region for dust storms, and over which large dust storms travel.

  2. Long-range transport of forest fire aerosol observed by Raman lidar

    NASA Astrophysics Data System (ADS)

    Vaughan, Geraint; Ricketts, Hugo; Bradley, Zoe

    2016-04-01

    Over the summer of 2014 and 2015 the Raman lidar system at Aberystwyth observed frequent occurrences of aerosol layers in the free troposphere, layers which are not observed at other times of the year. The Raman lidar can measure the optical depth and lidar ratio of these layers, giving an indication of their microsphysical properties. A summary of the observations will be presented, together with evidence that the aerosol originates from forest fires over North America. The hemispheric spread of absorbing aerosol, at a time of year when the northern latitudes are illuminated by the Sun, suggests that there may be implications for the Earth's radiation budget.

  3. Modeling the feedback between aerosol and meteorological variables in the atmospheric boundary layer during a severe fog-haze event over the North China Plain

    NASA Astrophysics Data System (ADS)

    Gao, Yi; Zhang, Meigen; Liu, Zirui; Wang, Lili; Wang, Pucai; Xia, Xiangao; Tao, Minghui; Zhu, Lingyun

    2016-04-01

    The feedback between aerosol and meteorological variables in the atmospheric boundary layer over the North China Plain (NCP) is analyzed by conducting numerical experiments with and without the aerosol direct and indirect effects via a coupled meteorology and aerosol/chemistry model(WRF-Chem). The numerical experiments are performed for the period of 2-26 January 2013, during which a severe fog-haze event (10-15 January 2013) occurred, with the simulated maximum hourly surface PM2.5 concentration of ~600 μg m-3, minimum atmospheric visibility of ~0.3 km, and 10-100 hours of simulated hourly surface PM2.5 concentration above 300 μg m-3 over NCP. A comparison of model results with aerosol feedback against observations indicates that the model can reproduce the spatial and temporal characteristics of temperature, relative humidity (RH), wind, surface PM2.5 concentration, atmospheric visibility, and aerosol optical depth reasonably well. Analysis of model results with and without aerosol feedback shows that during the fog-haze event aerosols lead to a significant negative radiative forcing of ~20 to ~140 W m-2 at the surface and a large positive radiative forcing of 20-120 W m-2 in the atmosphere and induce significant changes in meteorological variables with maximum changes during 09:00-18:00 local time (LT) over urban Beijing and Tianjin and south Hebei: the temperature decreases by 0.8-2.8 °C at the surface and increases by 0.1-0.5 °C at around 925 hPa, while RH increases by about 4-12% at the surface and decreases by 1-6% at around 925 hPa. As a result, the aerosol-induced equivalent potential temperature profile change shows that the atmosphere is much more stable and thus the surface wind speed decreases by up to 0.3 m s-1 (10 %) and the atmosphere boundary layer height decreases by 40-200 m (5-30 %) during the daytime of this severe fog-haze event. Owing to this more stable atmosphere during 09:00-18:00, 10-15 January, compared to the surface PM2

  4. Modeling the feedback between aerosol and meteorological variables in the atmospheric boundary layer during a severe fog-haze event over the North China Plain

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Zhang, M.; Liu, Z.; Wang, L.; Wang, P.; Xia, X.; Tao, M.

    2015-01-01

    The feedback between aerosol and meteorological variables in the atmospheric boundary layer over the North China Plain is analyzed by conducting numerical experiments with and without the aerosol direct and indirect effects via a coupled meteorology and aerosol/chemistry model (WRF-Chem). The numerical experiments are performed for the period 2-26 January 2013, during which a severe fog-haze event (10-15 January 2013) occurred. Comparison of the model results with aerosol feedback against observations indicates that the model can reproduce the spatial and temporal characteristics of temperature, relative humidity (RH), wind, surface PM2.5 concentration, atmospheric visibility, and aerosol optical depth. Comparison of modeling results in the presence and absence of aerosol feedback during the fog-haze event shows that aerosols lead to a significant negative radiative forcing of -20 to -140 W m-2 at the surface and a large positive radiative forcing of 20-120 W m-2 in the atmosphere and induce significant changes in meteorological variables of which the maximum changes occur during 09:00-18:00 LT over urban Beijing and Tianjin, and south Hebei Province: the temperature decreases by 0.8-2.8 °C at the surface and increases by 0.1-0.5 °C at around 925 hPa while the RH increases by about 4-12% at the surface and decreases by 1-6% at around 925 hPa. As a result, the aerosol-induced equivalent potential temperature profile change shows that the atmosphere is much more stable and thus the surface wind speed decreases by up to 0.3 m s-1 (10%) and the atmosphere boundary layer height decreases by 40-200 m (5-30%) during the daytime of this severe fog-haze event. Owing to this more stable atmosphere, during 09:00-18:00, 10-15 January, compared to the surface PM2.5 concentration from the model results without aerosol feedback, the average surface PM2.5 concentration increases by 10-50 μg m-3 (2-30%) over Beijing, Tianjin, and south Hebei province and the maximum increase of

  5. Modeling the feedback between aerosol and meteorological variables in the atmospheric boundary layer during a severe fog-haze event over the North China Plain

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Zhang, M.; Liu, Z.; Wang, L.; Wang, P.; Xia, X.; Tao, M.; Zhu, L.

    2015-04-01

    The feedback between aerosol and meteorological variables in the atmospheric boundary layer over the North China Plain (NCP) is analyzed by conducting numerical experiments with and without the aerosol direct and indirect effects via a coupled meteorology and aerosol/chemistry model (WRF-Chem). The numerical experiments are performed for the period of 2-26 January 2013, during which a severe fog-haze event (10-15 January 2013) occurred, with the simulated maximum hourly surface PM2.5 concentration of ~600 ug m-3, minimum atmospheric visibility of ~0.3 km, and 10-100 hours of simulated hourly surface PM2.5 concentration above 300 ug m-3 over NCP. A comparison of model results with aerosol feedback against observations indicates that the model can reproduce the spatial and temporal characteristics of temperature, relative humidity (RH), wind, surface PM2.5 concentration, atmospheric visibility, and aerosol optical depth reasonably well. Analysis of model results with and without aerosol feedback shows that during the fog-haze event aerosols lead to a significant negative radiative forcing of -20 to -140 W m-2 at the surface and a large positive radiative forcing of 20-120 W m-2 in the atmosphere and induce significant changes in meteorological variables with maximum changes during 09:00-18:00 local time (LT) over urban Beijing and Tianjin and south Hebei: the temperature decreases by 0.8-2.8 °C at the surface and increases by 0.1-0.5 °C at around 925 hPa, while RH increases by about 4-12% at the surface and decreases by 1-6% at around 925 hPa. As a result, the aerosol-induced equivalent potential temperature profile change shows that the atmosphere is much more stable and thus the surface wind speed decreases by up to 0.3 m s-1 (10%) and the atmosphere boundary layer height decreases by 40-200 m (5-30%) during the daytime of this severe fog-haze event. Owing to this more stable atmosphere during 09:00-18:00, 10-15~January, compared to the surface PM2

  6. Seasonal pattern of source and transport processes of natural and anthropic surfactants in coastal aerosol (Tuscany coast - Italy).

    NASA Astrophysics Data System (ADS)

    Becagli, Silvia; Ghedini, Costanza; Peeters, Stephane; Rottiers, Andre; Traversi, Rita; Udisti, Roberto; Jalba, Adriana; Dayan, Uri; Temara, Ali

    2010-05-01

    the fine and the coarse aerosol fractions indicated different sources and transport processes. MBAS concentrations show a clear maximum during the winter months in the fine fraction (PM 2.5) and summer maxima in the coarse (PM 10-2.5) fraction, and considering the prevailing different synoptic conditions in the different seasons, we suppose that MBAS have different dominant sources in the two seasons: in winter, MBAS likely originated from polluted continental areas, in the summer MBAS probably reflected the production of biogenic surfactants in the water mass during algal blooms or increased activity in the sea grass meadow. Low but detectable LAS concentrations could be measured mainly in the coarse fraction of the collected coastal aerosols. The data indicate a primary source of LAS, probably originating from the sea surface microlayer in coastal regions receiving untreated waste water discharge. Then, MBAS signal was not an appropriate surrogate measurement of LAS in aerosols. MBAS and LAS can have a primary marine source, but MBAS can be considered a marker of biogenic activity while LAS can be used as a marker of anthropogenic activity in areas receiving waste water discharges.

  7. The European aerosol budget in 2006

    NASA Astrophysics Data System (ADS)

    Aan de Brugh, J. M. J.; Schaap, M.; Vignati, E.; Dentener, F.; Kahnert, M.; Sofiev, M.; Huijnen, V.; Krol, M. C.

    2011-02-01

    This paper presents the aerosol budget over Europe in 2006 calculated with the global transport model TM5 coupled to the size-resolved aerosol module M7. Comparison with ground observations indicates that the model reproduces the observed concentrations quite well with an expected slight underestimation of PM10 due to missing emissions (e.g. resuspension). We model that a little less than half of the anthropogenic aerosols emitted in Europe are exported and the rest is removed by deposition. The anthropogenic aerosols are removed mostly by rain (95%) and only 5% is removed by dry deposition. For the larger natural aerosols, especially sea salt, a larger fraction is removed by dry processes (sea salt: 70%, mineral dust: 35%). We model transport of aerosols in the jet stream in the higher atmosphere and an import of Sahara dust from the south at high altitudes. Comparison with optical measurements shows that the model reproduces the Ångström parameter very well, which indicates a correct simulation of the aerosol size distribution. However, we underestimate the aerosol optical depth. Because the surface concentrations are close to the observations, the shortage of aerosol in the model is probably at higher altitudes. We show that the discrepancies are mainly caused by an overestimation of wet-removal rates. To match the observations, the wet-removal rates have to be scaled down by a factor of about 5. In that case the modelled ground-level concentrations of sulphate and sea salt increase by 50% (which deteriorates the match), while other components stay roughly the same. Finally, it is shown that in particular events, improved fire emission estimates may significantly improve the ability of the model to simulate the aerosol optical depth. We stress that discrepancies in aerosol models can be adequately analysed if all models would provide (regional) aerosol budgets, as presented in the current study.

  8. The European aerosol budget in 2006

    NASA Astrophysics Data System (ADS)

    Aan de Brugh, J. M. J.; Schaap, M.; Vignati, E.; Dentener, F.; Kahnert, M.; Sofiev, M.; Huijnen, V.; Krol, M. C.

    2010-09-01

    This paper presents the aerosol budget over Europe in 2006 calculated with the global transport model TM5 coupled to the size-resolved aerosol module M7. Comparison with ground observations indicates that the model reproduces the observed concentrations quite well with an expected slight underestimation of PM10 due to missing emissions (e.g. resuspension). We observe that a little less than half of the anthropogenic aerosols emitted in Europe are exported and the rest is removed by deposition. The anthropogenic aerosols are removed mostly by rain (95%) and only 5% is removed by dry deposition. For the larger natural aerosols, especially sea salt, a larger fraction is removed by dry processes (sea salt: 70%, mineral dust: 35%). We observe transport of aerosols in the jet stream in the higher atmosphere and an import of Sahara dust from the south at high altitudes. Comparison with optical measurements shows that the model reproduces the Ångström parameter very well, which indicates a correct simulation of the aerosol size distribution. However, we observe an underestimation of the aerosol optical depth. Because the surface concentrations are close to the observations, the shortage of aerosol in the model is probably at higher altitudes. We show that the discrepancies are mainly caused by an overestimation of wet-removal rates. To match the observations, the wet-removal rates have to be scaled down by a factor of about 5. In that case the modelled ground-level concentrations of sulphate and sea salt increase by 50% (which deteriorates the match), while other components stay roughly the same. Finally, it is shown that in particular events, improved fire emission estimates may significantly improve the ability of the model to simulate the aerosol optical depth. We stress that discrepancies in aerosol models can be adequately analysed if all models would provide (regional) aerosol budgets, as presented in the current study.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  10. Comment on "Large volcanic aerosol load in the stratosphere linked to Asian monsoon transport".

    PubMed

    Fromm, Michael; Nedoluha, Gerald; Charvát, Zdenek

    2013-02-01

    Bourassa et al. (Reports, 6 July 2012, p. 78) report on the 13 June 2011 eruption of the Nabro volcano and satellite observations of stratospheric aerosol that they attribute to troposphere to stratosphere ascent via the Asian monsoon. They claim (citing another source) that the 13 June top injection height was well below the tropopause. We will show that the 13 June Nabro eruption plume was clearly stratospheric and contained both volcanic gases and aerosols. Moreover, we will show height-resolved stratospheric sulfur dioxide and volcanic aerosol enhancements 1 to 3 days old, unaffected by the Asian monsoon, precisely connected to the volcano. The observed stratospheric aerosols and gases are fully explained by the 13 June eruption and do not require a monsoon vehicle. PMID:23393246

  11. Induction events and short-term regulation of electron transport in chloroplasts: an overview.

    PubMed

    Tikhonov, Alexander N

    2015-08-01

    Regulation of photosynthetic electron transport at different levels of structural and functional organization of photosynthetic apparatus provides efficient performance of oxygenic photosynthesis in plants. This review begins with a brief overview of the chloroplast electron transport chain. Then two noninvasive biophysical methods (measurements of slow induction of chlorophyll a fluorescence and EPR signals of oxidized P700 centers) are exemplified to illustrate the possibility of monitoring induction events in chloroplasts in vivo and in situ. Induction events in chloroplasts are considered and briefly discussed in the context of short-term mechanisms of the following regulatory processes: (i) pH-dependent control of the intersystem electron transport; (ii) the light-induced activation of the Calvin-Benson cycle; (iii) optimization of electron transport due to fitting alternative pathways of electron flow and partitioning light energy between photosystems I and II; and (iv) the light-induced remodeling of photosynthetic apparatus and thylakoid membranes.

  12. Isotope-Based Source Apportionment of EC Aerosol Particles during Winter High-Pollution Events at the Zeppelin Observatory, Svalbard.

    PubMed

    Winiger, Patrik; Andersson, August; Yttri, Karl E; Tunved, Peter; Gustafsson, Örjan

    2015-10-01

    Black carbon (BC) aerosol particles contribute to climate warming of the Arctic, yet both the sources and the source-related effects are currently poorly constrained. Bottom-up emission inventory (EI) approaches are challenged for BC in general and the Arctic in particular. For example, estimates from three different EI models on the fractional contribution to BC from biomass burning (north of 60° N) vary between 11% and 68%, each acknowledging large uncertainties. Here we present the first dual-carbon isotope-based (Δ(14)C and δ(13)C) source apportionment of elemental carbon (EC), the mass-based correspondent to optically defined BC, in the Arctic atmosphere. It targeted 14 high-loading and high-pollution events during January through March of 2009 at the Zeppelin Observatory (79° N; Svalbard, Norway), with these representing one-third of the total sampling period that was yet responsible for three-quarters of the total EC loading. The top-down source-diagnostic (14)C fingerprint constrained that 52 ± 15% (n = 12) of the EC stemmed from biomass burning. Including also two samples with 95% and 98% biomass contribution yield 57 ± 21% of EC from biomass burning. Significant variability in the stable carbon isotope signature indicated temporally shifting emissions between different fossil sources, likely including liquid fossil and gas flaring. Improved source constraints of Arctic BC both aids better understanding of effects and guides policy actions to mitigate emissions.

  13. Integration of prognostic aerosol-cloud interactions in a chemistry transport model coupled offline to a regional climate model

    NASA Astrophysics Data System (ADS)

    Thomas, M. A.; Kahnert, M.; Andersson, C.; Kokkola, H.; Hansson, U.; Jones, C.; Langner, J.; Devasthale, A.

    2015-06-01

    To reduce uncertainties and hence to obtain a better estimate of aerosol (direct and indirect) radiative forcing, next generation climate models aim for a tighter coupling between chemistry transport models and regional climate models and a better representation of aerosol-cloud interactions. In this study, this coupling is done by first forcing the Rossby Center regional climate model (RCA4) with ERA-Interim lateral boundaries and sea surface temperature (SST) using the standard cloud droplet number concentration (CDNC) formulation (hereafter, referred to as the "stand-alone RCA4 version" or "CTRL" simulation). In the stand-alone RCA4 version, CDNCs are constants distinguishing only between land and ocean surface. The meteorology from this simulation is then used to drive the chemistry transport model, Multiple-scale Atmospheric Transport and Chemistry (MATCH), which is coupled online with the aerosol dynamics model, Sectional Aerosol module for Large Scale Applications (SALSA). CDNC fields obtained from MATCH-SALSA are then fed back into a new RCA4 simulation. In this new simulation (referred to as "MOD" simulation), all parameters remain the same as in the first run except for the CDNCs provided by MATCH-SALSA. Simulations are carried out with this model setup for the period 2005-2012 over Europe, and the differences in cloud microphysical properties and radiative fluxes as a result of local CDNC changes and possible model responses are analysed. Our study shows substantial improvements in cloud microphysical properties with the input of the MATCH-SALSA derived 3-D CDNCs compared to the stand-alone RCA4 version. This model setup improves the spatial, seasonal and vertical distribution of CDNCs with a higher concentration observed over central Europe during boreal summer (JJA) and over eastern Europe and Russia during winter (DJF). Realistic cloud droplet radii (CD radii) values have been simulated with the maxima reaching 13 μm, whereas in the stand

  14. Analysis of Characteristics of Dust Aerosols in Northwest China based on Satellite Remote-sensing Data

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Liu, D.; Zhao, Q.

    2015-12-01

    Based on the CloudSat data, effects of dust aerosol on cloud parameters under the circumstance of the monthly average, dusty days and dust-free days were analyzed during April, 2010. By using L2 aerosol profiles satellite data of CALIOP/CALIOPSO the aerosol extinction coefficients were analyzed over northwest China. As an important case, space distribution and transmission route of dust aerosol were investigated during the dust events occurred from April 16th to 18th in 2013 over northwest China, based on L1 data of CALIOP/CALIOPSO, a combination of multiple satellite data and models. The results show that (1) dust aerosols could cause the reduction in effective radius of particle, cloud liquid water content and cloud optical thickness, and the increase of the number concentration of liquid cloud particles as well, (2) The aerosol extinction coefficients were decreased with the increase of height. The value of the aerosol extinction coefficients in desert area was greater than that in the area of Gansu Province due to urbanization. Distribution of the aerosol extinction coefficients in spring was nearly the same as the annual average. (3) Using aerosol products of the vertical characteristics from CALIOP/CALIOPSO, aerosol was classified during dust events, and with NAPPS Global aerosol model, daily distribution of the dust aerosol concentration was given, showing the transport and diffusion of dust aerosol. With HYSPLIT trajectory model dust transportation path of the sand dust source areas was simulated and identified. During the outbreak of dust event dust aerosol was mainly distributed over the surface about 3km, with depolarization ratio at 0.4 and color ratio at 1.2. During the dust events were close to weak and stop, dust aerosol was mainly distributed over the surface under 2 km, with depolarization ratio from 0.2 to 0.3, and color ratio about 1.

  15. Influence of anthropogenic aerosol on cloud optical depth and albedo shown by satellite measurements and chemical transport modeling.

    PubMed

    Schwartz, Stephen E; Harshvardhan; Benkovitz, Carmen M

    2002-02-19

    The Twomey effect of enhanced cloud droplet concentration, optical depth, and albedo caused by anthropogenic aerosols is thought to contribute substantially to radiative forcing of climate change over the industrial period. However, present model-based estimates of this indirect forcing are highly uncertain. Satellite-based measurements would provide global or near-global coverage of this effect, but previous efforts to identify and quantify enhancement of cloud albedo caused by anthropogenic aerosols in satellite observations have been limited, largely because of strong dependence of albedo on cloud liquid water path (LWP), which is inherently highly variable. Here we examine satellite-derived cloud radiative properties over two 1-week episodes for which a chemical transport and transformation model indicates substantial influx of sulfate aerosol from industrial regions of Europe or North America to remote areas of the North Atlantic. Despite absence of discernible dependence of optical depth or albedo on modeled sulfate loading, examination of the dependence of these quantities on LWP readily permits detection and quantification of increases correlated with sulfate loading, which are otherwise masked by variability of LWP, demonstrating brightening of clouds because of the Twomey effect on a synoptic scale. Median cloud-top spherical albedo was enhanced over these episodes, relative to the unperturbed base case for the same LWP distribution, by 0.02 to 0.15.

  16. Comparison of NO2 long-range transport events in GOME-2 observations and CTM simulations

    NASA Astrophysics Data System (ADS)

    Zien, A.; Hilboll, A.; Richter, A.; Burrows, J. P.

    2012-04-01

    Atmospheric long-range transport (LRT) events relocate trace gases from emission to downwind regions on an intercontinental scale, drastically altering the atmospheric chemistry in remote regions. Tropospheric NO2 is a very short-lived, mainly anthropogenic trace gas with strong impact on the ozone chemistry. Emissions are very localized and allow identification of individual LRT events. Here, the phenomenon of NO2 LRT is investigated by satellite remote sensing observations and global chemical transport modelling, which both provide good spatial and temporal coverage as well as sufficient resolution for the identification of large-scale, multi-day events. This allows the modelled and measured estimation of seasonal, regional and global LRT statistics. We use a non-cloud-filtered GOME-2 NO2 observational data set and model data from global GEOS-Chem simulations. A dedicated algorithm is used to identify and verify LRT events in observational and model data. We present the comparison of these results concerning the occurrence of NO2 LRT events. We discuss seasonalities in frequency and typical routes of LRTs and compare estimations of the transported mass from observations to results from the model. Further, we discuss peculiarities in the comparison between results from models and observations.

  17. Impact of long-range transport on aerosol properties at a regional background station in Northern China

    NASA Astrophysics Data System (ADS)

    Pu, Weiwei; Zhao, Xiujuan; Shi, Xuefeng; Ma, Zhiqiang; Zhang, Xiaoling; Yu, Bo

    2015-02-01

    The impact of long-range transport on aerosol properties at SDZ regional background station in Northern China during 2005-2010, was analyzed using trajectory clustering method with 3-day, 6-hourly backward trajectories determined by using HYSPLIT 4 model. Eleven clusters were determined by using the two-stage cluster method. PM2.5 levels, aerosol scattering coefficient (σsp) and scattering efficiency (αsp_2.5) of PM2.5 associated with each cluster were calculated. Based on the levels of PM2.5 and σsp, eleven clusters were classified into a relatively "clean" group (group A) and a "polluted" group (group B). The PM2.5 concentration and σsp of group A were lower than that of group B. Group A was mainly composed of the trajectories from northwest, north and northeast, which originated and passed through the emission areas such as Mongolia and Inner Mongolia. Group B mostly consisted of the air masses from the south and southeast, and the ones from the northwest. It was characterized with short and low trajectories over major anthropogenic emission regions in North China Plain (NCP), northwestern Hebei province and Inner Mongolia. The trajectory pathway of the northwest cluster in group B was lowest and slowest among all clusters from northerly direction, which caused the accumulation of pollutants along this pathway. High PM hours were identified in each cluster for each month, and were found mainly in group B, especially during March to October. Except of the contribution of high PM2.5 emissions in NCP, the production of secondary aerosols with the increasing solar radiation and humidity from March to October, and the straw burning that usually occurs in June in NCP are responsible for the high PM2.5 as well. The characteristics of αsp_2.5 of each cluster indicated that the northerly clusters were affected by anthropogenic pollutants mixed with dust, but southerly clusters were only influenced by the pollution aerosols. The αsp_2.5 of dust and anthropogenic

  18. Analysis of an ordinary bedload transport event in a mountain torrent (Rio Vanti, Verona, Italy)

    NASA Astrophysics Data System (ADS)

    Pastorello, Roberta; D'Agostino, Vincenzo

    2016-04-01

    The correct simulation of the sediment-transport response of mountain torrents both for extreme and ordinary flood events is a fundamental step to understand the process, but also to drive proper decisions on the protection works. The objective of this research contribution is to reconstruct the 'ordinary' flood event with the associated sediment-graph of a flood that caused on the 14th of October, 2014 the formation of a little debris cone (about 200-210 m3) at the junction between the 'Rio Vanti' torrent catchment and the 'Selva di Progno' torrent (Veneto Region, Prealps, Verona, Italy). To this purpose, it is important to notice that a great part of equations developed for the computation of the bedload transport capacity, like for example that of Schoklitsch (1962) or Smart and Jaeggi (1983), are focused on extraordinary events heavily affecting the river-bed armour. These formulas do not provide reliable results if used on events, like the one under analysis, not too far from the bankfull conditions. The Rio Vanti event was characterized by a total rainfall depth of 36.2 mm and a back-calculated peak discharge of 6.12 m3/s with a return period of 1-2 years. The classical equations to assess the sediment transport capacity overestimate the total volume of the event of several orders of magnitude. By the consequence, the following experimental bedload transport equation has been applied (D'Agostino and Lenzi, 1999), which is valid for ordinary flood events (q: unit water discharge; qc: unit discharge of bedload transport initiation; qs: unit bedload rate; S: thalweg slope): -qs-˜= 0,04ṡ(q- qc) S3/2 In particular, starting from the real rainfall data, the hydrograph and the sediment-graph have been reconstructed. Then, comparing the total volume calculated via the above cited equation to the real volume estimated using DoD techniques on post-event photogrammetric survey, a very satisfactory agreement has been obtained. The result further supports the thesis

  19. Tracking Transport and Transformation of Aerosols using C and O-triple Isotopic Composition of Carbonates: CSI La Jolla

    NASA Astrophysics Data System (ADS)

    Thiemens, M. H.; Shaheen, R.; Chong, K.; Hill, A.; Wong, J.; Zhang, Z.; Dominguez, G.

    2012-12-01

    Aerosols affect climate in numerous ways, including change in the earth's energy balance by absorbing and scattering solar radiations, alteration of the hydrological cycle by serving as cloud condensation nuclei, change in biogeochemical cycles by providing nutrients. Another significant process is the effect on the chemical composition of the atmosphere by providing surfaces for heterogeneous chemical reactions. Fine particles of aerodynamic diameter less than 2.5μm (PM2.5) also impinge upon human health by admission to the respiratory system causing a range of cardiopulmonary diseases. Both climate and public health aspects depend on their physical and chemical properties, therefore, understanding physico-chemical and photochemical transformations on aerosol surfaces is important for predicting their effects on climate change, atmospheric chemistry and human health. Here we present initial findings on the processes occurring on aerosol surfaces using isotopes to delineate day and night time chemistry, thus resolving photochemistry effects, and to identify their sources by way of the carbon isotopes. Aerosols were collected on filter papers for 12h during the day and at night time from June-Dec. 2011in La Jolla, CA., using high volume, multi stage cascade impactors. CO2 released after treating these filter papers with 100% phosphoric acid at 27oC was collected, purified chromatographically and analyzed for both C and O isotopes. Our data indicate that both C and O isotopes can be used to distinguish between heterogeneous and photochemical transformations. Aerosol carbonates collected during the day time were depleted in δ13Cday = -23 to -28‰ and δ18Oday = +3 to +10‰ and were isotopically distinct from the carbonates collected at night time δ13Cnight = 0 to -12‰, δ18Onightnight = +23 to +32‰. Higher chloride concentration in the samples collected at night time indicated the transport of marine air masses whereas higher nitrate and sulfate concentration

  20. The long-range transport of aerosols from northern China to Hong Kong - a multi-technique study

    NASA Astrophysics Data System (ADS)

    Fang, M.; Zheng, M.; Wang, F.; Chim, K. S.; Kot, S. C.

    The results of the inorganic and organic analyses of aerosol samples collected on the east and west sides of Hong Kong during a dust episode (9-10 May 1996) are reported. The origin of the dust was traced to Northern China. The dust reached Hong Kong by way of the East China Sea. The characteristics of the inorganic elements and organic compounds were quite different from the non-episodic samples collected on 1-2 April 1996, EPD (Environmental Protection Department, Special Administrative Region, Hong Kong, China) results for April-May 1994, and our early studies (Zheng et al., 1997. Atmospheric Environment 31(2), 227-237.). Results from X-ray spectrometry showed pronounced increase in the relative abundance of Al, Fe, Ca, S and Cl in the dust samples compared to the non-episodic samples. The high abundance of Cl in the dust samples suggested the aerosols experienced long-range transport by way of the sea. ICP-MS analysis revealed higher concentrations of Fe, Ca, S and Pb in the episodic samples relative to the values measured during April-May 1994 by EPD. The high Ca content in the soil samples is a characteristic of northern Chinese crustal material (Liu et al., 1985). Hong Kong aerosols are characterized by high octadecenoic acid concentration due to heavy urbanization and Chinese-style stir-fry cooking. A much lower C 18:1/C 18:0 ratio was found in the episodic samples, however, suggesting the aerosols were transported from a long distance. The high ratio of ⩾C 20/aerosol samples collected during the episode corresponded well with those of the eolian dust samples over the Atlantic and Pacific Oceans. Back trajectories and low altitude (<3 km) mesoscale flow modeling

  1. Coupled Effects of Vadose Zone Hydrodynamics and Anionic Surfactant Aerosol-22 on the Transport of Cryptosporidium parvum in Soil

    NASA Astrophysics Data System (ADS)

    Darnault, C. J.; Jacobson, A. R.; Powelson, D.; Baveye, P.; Peng, Z.; Yu, C.

    2013-12-01

    Cryptosporidium parvum is a microbial pathogen that may be found in soil, surface and groundwater resources. We studied their transport behavior under conditions where both C. parvum oocysts and chemicals that may affect their mobility are present in soils. Surfactants occur widely in soils due to agricultural practices such as wastewater irrigation and application of agrichemicals. Surfactants decrease the surface tension of the soil solution, which may reduce the ability of C. parvum oocysts to be retained at gas-water interfaces. Understanding the fate and transport of C. parvum oocysts following land application of manure and use of surfactants in rural and agricultural watersheds is critical to assess the threat to water resources. We investigated the coupled effects of vadose zone hydrodynamics and an anionic surfactant Aerosol-22 on the transport of C. parvum oocysts in natural structured and non-structured agricultural or range soils from Illinois and Utah. Column transport experiments consisted of unsaturated flow subject to macropore and fingered flows resulting from simulated rainfall with and without surfactant. To assess the behavior of C. parvum oocysts in soils, the breakthrough and distribution of C. parvum oocysts in soil profiles were obtained using qPCR. We observed that surfactant enhanced the transport of C. parvum oocysts when preferential flow paths are present. However, when the interconnection between macropores is not established in the soils, surfactant limited the transport of C. parvum oocysts through the soil matrix by forming oocyst-surfactant-Ca flocs.

  2. Effect of Long-Range Aerosol Transport on the Microphysical Properties of Low-Level Clouds in the Arctic

    NASA Astrophysics Data System (ADS)

    Coopman, Q.; Garrett, T. J.; Riedi, J.; Finch, D.

    2015-12-01

    The Arctic region is influenced by elevated concentration of aerosols from mid-latitudes. By acting as Cloud Condensation Nuclei (CCN) and/or Ice Nuclei (IN), these aerosols influence cloud presence and formation, and in turn cloud radiative properties and forcing. We analyze the impact of pollution plumes on cloud microphysical properties, including droplet effective radius and cloud optical depth, by calculating an indirect effect (IE) parameter. This IE parameter is defined by the ratio of relative change in cloud microphysical properties to relative variations in pollution concentrations. We also study the impact of aerosols on the cloud thermodynamic phase. In our study we used three sets of data: (i) A combination of POLDER-3/PARASOL and MODIS/AQUA satellite measurements to retrieve cloud properties, (ii) an atmospheric chemistry transport model GEOS-Chem carbon monoxide tracer for concentrations of biomass burning and anthropogenic pollution plumes, (iii) and reanalysis data from ECMWF for the meteorological state. The pollution plumes from biomass burning sources appear to be good IN, whereas pollution from anthropogenic sources appears to act as better CCN. We extend the analysis to different specific humidity and stability regimes to find that the specific humidity and lower tropospheric stability increase the cloud microphysical sensitivity to pollution loading. For example, for low specific humidity situations the IE parameter is close to zero whereas for the highest values of specific humidity - greater than 5 g kg-1 - the impact of aerosols is a maximum: The IE parameter is up to 0.1 and 0.2 for the effective radius and the optical depth respectively. When the lower tropospheric stability is greater than 25˚K, the IE parameter is approximately 0.3 for the optical depth. We hypothesize that the observed correlation between IE and stability is because cloud formation in the Arctic region is dominated by radiative cooling.

  3. TN-68 Spent Fuel Transport Cask Analytical Evaluation for Drop Events

    SciTech Connect

    Shah, M. J.; Klymyshyn, Nicholas A.; Adkins, Harold E.; Koeppel, Brian J.

    2007-03-30

    The U.S. Nuclear Regulatory Commission (NRC) is responsible for licensing commercial spent nuclear fuel transported in casks certified by NRC under the Code of Federal Regulations (10 CFR), Title 10, Part 71 [1]. Both the International Atomic Energy Agency regulations for transporting radioactive materials [2, paragraph 727], and 10 CFR 71.73 require casks to be evaluated for hypothetical accident conditions, which includes a 9-meter (m) (30-ft) drop-impact event onto a flat, essentially unyielding, horizontal surface, in the most damaging orientation. This paper examines the behavior of one of the NRC certified transportation casks, the TN-68 [3], for drop-impact events. The specific area examined is the behavior of the bolted connections in the cask body and the closure lid, which are significantly loaded during the hypothetical drop-impact event. Analytical work to evaluate the NRC-certified TN-68 spent fuel transport cask [3] for a 9-m (30-ft) drop-impact event on a flat, unyielding, horizontal surface, was performed using the ANSYS® [4] and LS DYNA™ [5] finite-element analysis codes. The models were sufficiently detailed, in the areas of bolt closure interfaces and containment boundaries, to evaluate the structural integrity of the bolted connections under 9-m (30-ft) free-drop hypothetical accident conditions, as specified in 10 CFR 71.73. Evaluation of the cask for puncture, caused by a free drop through a distance of 1-m (40-in.) onto a mild steel bar mounted on a flat, essentially unyielding, horizontal surface, required by 10 CFR 71.73, was not included in the current work, and will have to be addressed in the future. Based on the analyses performed to date, it is concluded that, even though brief separation of the flange and the lid surfaces may occur under some conditions, the seals would close at the end of the drop events, because the materials remain elastic during the duration of the event.

  4. Synergy of multispectral and multisensors satellite observations to evaluate desert aerosol transport and impact of dust deposition on inland waters: study case of Lake Garda

    NASA Astrophysics Data System (ADS)

    Di Nicolantonio, Walter; Cazzaniga, Ilaria; Cacciari, Alessandra; Bresciani, Mariano; Giardino, Claudia

    2015-01-01

    The capabilities of different Earth Observation multispectral satellites are employed for detecting and tracking of desert dust coming from North Africa toward the Northern Italy area and for evaluating the impact of Saharan dust deposition in inland waters, such as those of Lake Garda. Absorbing and scattering spectral optical properties of desert aerosol in the atmospheric windows in the ultraviolet, visible-near-infrared, and infrared spectral ranges are exploited in the dust retrieval performed by OMI/Aura, MODIS/Terra-Aqua, and SEVIRI/MSG satellite sensors. Therefore, the direct link between dust deposition and increase in phytoplankton abundance has been assessed retrieving MERIS-based chlorophyll-a (chl-a) concentration for the desert dust events. Estimates of the increased chl-a in the lake have been derived with values in concentration from 30% to 170%. AERONET sun-photometer measurements, gravimetric particulate matter samplings, in situ chl-a concentration and surface temperature are employed to select events and assess the presence of desert dust and recognize a corresponding increase of the phytoplankton abundance in the analyzed inland waters. The improved observational features that will be provided by the next European Sentinels missions, namely Sentinel-2, 3, 4, 5P, together with MTG-I (Imager) and MTG-S (Sounder) will allow better monitoring atmospheric constituents and studying the environmental impacts of desert dust transport.

  5. Characterization of thyroid hormone transporter expression during tissue-specific metamorphic events in Xenopus tropicalis.

    PubMed

    Connors, Kristin A; Korte, Joseph J; Anderson, Grant W; Degitz, Sigmund J

    2010-08-01

    Thyroid hormone (TH) induces the dramatic morphological and physiological changes that together comprise amphibian metamorphosis. TH-responsive tissues vary widely with developmental timing of TH-induced changes. How larval tadpole tissues are able to employ distinct metamorphic programs in a developmental stage- and TH-dependent manner is still unknown. Recently, several proteins capable of transporting TH have been identified. TH action and metabolism occurs primarily intracellularly, highlighting the importance of TH transporters. We examined the hypothesis that TH transporter expression and tissue distribution play an important role in mediating TH-induced metamorphic events. Xenopus tropicalis homologs for known TH transporting OATP, MCT and LAT family proteins were identified and gene specific qRT-PCR primers were developed. Total RNA was extracted from tissues representing three unique developmental fates including: growth/differentiation (hind limb), death/resorption (gill, tail) and remodeling (brain, liver, kidney). For growing and resorbing tissues, results showed the general trend of low initial expression levels of MCT8 and MCT10 transporters, followed by a several-fold increase of expression as the tissue undergoes TH-dependent metamorphic changes. The expression pattern in remodeling tissues was less uniform: a general decrease in transporter expression was observed in the liver, while the kidney and brain exhibited a range of expression patterns for several TH transporters. Collectively, these developmental expression patterns are consistent with TH transporting proteins playing a role in the effects of TH in peripheral tissues.

  6. Evaluation of long range transport of fossil fuel originated organic aerosol at a background site in Northeast Asia

    NASA Astrophysics Data System (ADS)

    Hwang, Eun Jin; Lee, Ji Yi; Park, Jin Soo; Lee, Seok Jo; Kim, Hyun Jae; Jeon, Ha Eun; Sung, Min Young

    2013-04-01

    Northeast Asia is heavy air pollution region due to usage of large amounts of fossil fuel. In addition, meteorological conditions represented as prevailing westerlies in Northeast Asia region causes long range transport of anthropogenic pollutants emitted from China to Korea and Japan and even the United States across the Pacific Ocean (Bey et al., 2001). The Baengnyeong Island of Korea is located at the northwestern part of the Korean peninsula and close by North Korea and China, thus this site is regarded as an ideal place for background air measurements in Northeast Asia. Also, it has low local anthropogenic emissions and is frequently influenced by various air masses from China and North Korea in the Island. In this study, we performed intensive sampling during summer and winter in the Baengnyeong Island and analyzed various organic compounds including fossil fuel originated organic markers such as hopanes and PAHs using thermal desorption two dimensional gas chromatography with time of flight mass spectrometry (TD-GC×GC-TOFMS). We also analyzed ~20 urban aerosol samples collected at Seoul, a representative urban site in Northeast Asia region to compare organic compounds distributions of aerosol samples at the Baengnyeong Island. By applying air mass back trajectory analysis and comparing organic compounds distributions in aerosol samples of the Baengnyeong Island and Seoul, the impact of long-range transport of fossil fuel originated organic pollutants at a background site in Northeast Asia were evaluated. (References) Bey, I., Jacob, D.J., Logan, J.A., Yantosca, R.M., 2001. Asian chemical outflow to the Pacific in spring: origins, pathways, and budgets. Journal of Geophysical Research-Atmosphere 106, 23097-23113.

  7. Variability in aerosol optical properties over an urban site, Kanpur, in the Indo-Gangetic Plain: A case study of haze and dust events

    NASA Astrophysics Data System (ADS)

    Ram, Kirpa; Singh, Sunita; Sarin, M. M.; Srivastava, A. K.; Tripathi, S. N.

    2016-06-01

    In this study, we report on three important optical parameters, viz. absorption and scattering coefficients (babs, bscat) and single scattering abledo (SSA) based on one-year chemical-composition data collected from an urban site (Kanpur) in the Indo-Gangetic-Plain (IGP) of northern India. In addition, absorption Ängstrom exponent (AAE) was also estimated in order to understand the wavelength dependence of absorption and to decipher emission sources of carbonaceous aerosols, in particular of black carbon. The absorption and scattering coefficients ranged between 8.3 to 95.2 Mm- 1 (1 Mm- 1 = 10- 6 m- 1) and 58 to 564 Mm- 1, respectively during the study period (for n = 66; from January 2007 to March 2008) and exhibit large seasonal variability with higher values occurring in winter and lower in the summer. Single scattering albedo varied from 0.65 to 0.92 whereas AAE ranged from 0.79 to 1.40 during pre-monsoon and winter seasons, respectively. The strong seasonal variability in aerosol optical properties is attributed to varying contribution from different emission sources of carbonaceous aerosols in the IGP. A case study of haze and dust events further provide information on extreme variability in aerosol optical parameters, particularly SSA, a crucial parameter in atmospheric radiative forcing estimates.

  8. 40 CFR 53.59 - Aerosol transport test for Class I equivalent method samplers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... specified in 40 CFR part 50, appendix L or appendix O, as applicable. The test requirements and performance... specified for a reference method sampler in 40 CFR part 50, appendix L or appendix O, as applicable, such as... candidate samplers in which the aerosol flow path (the flow path through which sample air passes upstream...

  9. 40 CFR 53.59 - Aerosol transport test for Class I equivalent method samplers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... specified in 40 CFR part 50, appendix L or appendix O, as applicable. The test requirements and performance... specified for a reference method sampler in 40 CFR part 50, appendix L or appendix O, as applicable, such as... candidate samplers in which the aerosol flow path (the flow path through which sample air passes upstream...

  10. Measurements of HNO3, SO2 High Resolution Aerosol SO4 (sup 2-), and Selected Aerosol Species Aboard the NASA DC-8 Aircraft: During the Transport and Chemical Evolution Over the Pacific Airborne Mission (TRACE-P)

    NASA Technical Reports Server (NTRS)

    Talbot, Robert W.; Dibb, Jack E.

    2004-01-01

    The UNH investigation during TRACE-P provided measurements of selected acidic gases and aerosol species aboard the NASA DC-8 research aircraft. Our investigation focused on measuring HNO3, SO2, and fine (less than 2 microns) aerosol SO4(sup 2-) with two minute time resolution in near-real-time. We also quantified mixing ratios of aerosol ionic species, and aerosol (210)Pb and (7)Be collected onto bulk filters at better than 10 minute resolution. This suite of measurements contributed extensively to achieving the principal objectives of TRACE-P. In the context of the full data set collected by experimental teams on the DC-8, our observations provide a solid basis for assessing decadal changes in the chemical composition and source strength of Asian continental outflow. This region of the Pacific should be impacted profoundly by Asian emissions at this time with significant degradation of air quality over the next few decades. Atmospheric measurements in the western Pacific region will provide a valuable time series to help quantify the impact of Asian anthropogenic activities. Our data also provide important insight into the chemical and physical processes transforming Asian outflow during transport over the Pacific, particularly uptake and reactions of soluble gases on aerosol particles. In addition, the TRACE-P data set provide strong constraints for assessing and improving the chemical fields simulated by chemical transport models.

  11. Systematic Quantitative Analysis of NO2 Long-Range Transport Events and Comparison to Model Data

    NASA Astrophysics Data System (ADS)

    Zien, A. W.; Richter, A.; Hilboll, A.; Burrows, J. P.; Inness, A.

    2012-12-01

    Atmospheric long-range transport (LRT) events relocate trace gases from emission to downwind regions on an intercontinental scale, drastically altering the atmospheric chemistry in remote regions. Tropospheric NO2 is a very short-lived, mainly anthropogenic trace gas with strong impact on the ozone chemistry. Emissions are very localized and allow identification of individual LRT events. In this study, we use non-cloud-filtered remote sensing observations from the GOME-2 satellite instrument to identify trans-oceanic NO2 LRT events. The LRT analysis is performed by a specialized algorithm, spotting anomalies in the vertical slant column data. LRT routes are obtained via Lagrangian back-tracing with the HYSPLIT model. We also implement a radiance cloud-fraction and model the NO2 air-mass factor in LRTs to allow the quantification of NO2 content under cloudy conditions which frequently accompany LRTs. Sample LRT events over the North Atlantic and the Southern Ocean illustrate the process and results of this analysis. The spatial and temporal coverage of the used observations also allows for a statistical analysis, showing regional and seasonal features in both LRT occurrence and properties in a 5-year data set (2007 to 2011), giving typical routes of transport. We compare these to results from a similar analysis of data from a global chemical transport model, the MACC reanalysis data.

  12. Response of a Spent Fuel Transportation Cask to a Tunnel Fire Event

    SciTech Connect

    Bajwa, C. S.

    2003-02-25

    The staff of the Spent Fuel Project Office at the U.S. Nuclear Regulatory Commission undertook the investigation and thermal analysis of the Baltimore tunnel fire event. This event occurred in the Howard Street tunnel, in Baltimore, Maryland, on July 18, 2001. The staff was tasked with assessing the consequences of this event on the transportation of spent nuclear fuel. This paper describes the staff's coordination with the following government and laboratory organizations: the National Transportation Safety Board (NTSB), to determine the details of the train derailment and fire; the National Institute of Standards and Technology (NIST), to quantify the thermal conditions within the tunnel; the Center for Nuclear Waste Regulatory Analysis (CNWRA), to validate the NIST evaluations, and the Pacific Northwest National Laboratory (PNNL), to assist in the thermal analysis. The results of the staff's review and analysis efforts are also discussed. The staff has concluded that had the spent fuel transportation cask analyzed, a design approved under 10 CFR Part 71, been subjected to the Howard Street tunnel fire, no release of radioactive materials would have resulted from this postulated event, and the health and safety of the public would have been maintained.

  13. Transport of breeder reactor-fire-generated sodium oxide aerosols for building-wake-dominated meteorology

    SciTech Connect

    Fields, D.E.; Cooper, A.C.; Miller, C.W.

    1987-02-01

    This report describes the methodology used and results obtained in efforts to estimate the sodium aerosol concentrations at air intake ports of a liquid-metal cooled, fast-breeder nuclear reactor. An earlier version of this methodology has been previously discussed (Fields and Miller, 1985). A range of wind speeds from 2 to 10 m/s is assumed, and an effort is made to include building wake effects which, in many cases, dominate the dispersal of aerosols near buildings. For relatively small release rates, on the order of 1 to 10 kg/s, the plume rise is small and estimates of aerosol concentrations are derived using the methodology of Wilson and Britter (1982), which describes releases from surface vents. For release rates on the order of 100 kg/s much higher release velocities are expected, and plume rise is considered. An effective increase in release height is computed using the Split-H methodology with a parameterization suggested by Ramsdell (1983), and the release source strength is transformed to rooftop level. Evaluation of the acute release aerosol concentration is then based on the methodology for releases from a surface release of this transformed source strength. For a horizontal release, a methodology is developed to chart the plume path as a function of release and site meteorology parameters. Results described herein must be regarded as maximum aerosol concentrations, based on models derived from generic wind tunnel studies. More accurate and site-specific results may be obtained through wind tunnel simulations and through simulating emissions from release points other than those assumed here.

  14. Aerosols in Polluted versus Nonpolluted Air Masses: Long-Range Transport and Effects on Clouds.

    NASA Astrophysics Data System (ADS)

    Pueschel, R. F.; van Valin, C. C.; Castillo, R. C.; Kadlecek, J. A.; Ganor, E.

    1986-12-01

    To assess the influence of anthropogenic aerosols on the physics and chemistry of clouds in the northeastern United State, aerosol and cloud-drop size distributions, elemental composition of aerosols as a function of size, and ionic content of cloud water were measured on Whiteface Mountain, New York, during the summers of 1981 and 1982. In several case studies, the data were cross-correlated with different air mass types-background continental, polluted continental, and maritime-that were advected to the sampling site. The results are the following (1) Anthropogenic sources hundreds of kilometers upwind cause the small-particle (accumulation) mode number to increase from hundreds to thousands per cubic centimeter and the mass loading to increase from a few to several tens of micrograms per cubic meter, mostly in the form of sulfur aerosols. (ii) A significant fraction of anthropogenic sulfur aerosols appears to act as cloud condensation nuclei (CCN) to affect the cloud drop concentration. (iii) Clouds in Atlantic maritime air masses have cloud drop spectra that are markedly different from those measured in continental clouds. The drop concentration is significantly lower, and the drop size spectra are heavily skewed toward large drops. (iv) Effects of anthropogenic pollutants on cloud water ionic composition are an increase of nitrate by a factor of 50, an increase of sulfate by more than one order of magnitude, and an increase of ammonium ion by a factor of 7. The net effect of the changes in ionic concentrations is an increase in cloud water acidity. An anion deficit even in maritime clouds suggests an unknown, possibly biogenic, source that could be responsible for a pH below neutral, which is frequently observed in nonpolluted clouds.

  15. The Effect of the Anionic Surfactant Aerosol-80 on the Transport of Cryptosporidium parvum Oocysts through Soil

    NASA Astrophysics Data System (ADS)

    Jacobson, A. R.; Powelson, D.; Darnault, C.

    2012-12-01

    Transport of the pathogenic protozoan Cryptosporidium parvum through soils threatens ground and surface waters. C. parvum may be introduced into soils in the manure of infected calves. The presence of other chemicals in the soil applied as or with amendments, may affect the transport of the C. parvum oocysts. Surfactants, which are used in many herbicide formulations, decrease water tension and may disrupt the air-water interface where oocysts are thought to accumulate. We investigate the effect of the anionic surfactant Aerosol-80, at two concentrations, on the transport of C. parvum oocysts by unsaturated flow through "undisturbed" soil columns from Illinois and Utah. Following each experiment oocysts in the leachate and distributed throughout the soil profile are quantified by real time PCR. We find that the presence of the surfactant accelerates the transport of the oocysts through preferential flow paths. On the other hand, when connected macropores are not present in the soils, the presence of the surfactant retards the transport of the oocysts through the soil matrix by straining oocyst-surfactant-Ca flocs. Surfactant efficacy is affected by soil type.

  16. Global Simulation of Ammonium-sulfate-nitrate Inorganic Aerosols: Implications for Natural Visibility in the United States and Intercontinental Transport of Pollution

    NASA Astrophysics Data System (ADS)

    Park, R. J.; Jacob, D. J.; Field, B. D.; Evans, M. J.; Yantosca, R. M.; Chin, M.

    2003-12-01

    We use a global 3-D coupled oxidant-aerosol model (GEOS-CHEM) to quantify natural and transboundary pollution influences on sulfate-nitrate-ammonium aerosol concentrations in the United States. This work is motivated by the EPA Regional Haze Rule, which requires immediate action to improve visibility in U.S. wilderness areas towards an endpoint of natural visibility conditions by 2064. We present full-year simulations for 1998 and 2001 and evaluate them with nationwide networks of observations in the U.S. and Europe (IMPROVE, CASTNET, NADP, EMEP). Sulfate results are unbiased across all seasons, representing a major improvement over previous models. Ammonia emissions are too high in fall and possible reasons are discussed. Shutting off U.S. anthropogenic emissions in the model defines residual aerosol concentrations in the U.S. representing contributions from natural and transboundary pollution sources. We find that this residual is dominated by transboundary transport of pollution from Canada, Mexico, and Asia. Transpacific transport of Asian anthropogenic aerosol accounts for 30% of residual ammonium sulfate in both the western and eastern U.S. We find that achievement of natural visibility anywhere in the U.S. is seriously compromised by transboundary transport of anthropogenic sulfate-nitrate-ammonium aerosols. This is in contrast to carbonaceous aerosols, for which we previously found that natural sources dominate over transboundary transport of pollution. Our best estimates of residual aerosol concentrations in the U.S. are 2-4 times higher than the default values recommended by the EPA for natural visibility calculations, with major implications for emission controls to be implemented over the next decade.

  17. Aerosol transport and wet scavenging in deep convective clouds: a case study and model evaluation using a multiple passive tracer analysis approach

    SciTech Connect

    Yang, Qing; Easter, Richard C.; Campuzano-Jost, Pedro; Jimenez, Jose L.; Fast, Jerome D.; Ghan, Steven J.; Wang, Hailong; Berg, Larry K.; Barth, Mary; Liu, Ying; Shrivastava, ManishKumar B.; Singh, Balwinder; Morrison, H.; Fan, Jiwen; Ziegler, Conrad L.; Bela, Megan; Apel, Eric; Diskin, G. S.; Mikoviny, Tomas; Wisthaler, Armin

    2015-08-20

    The effect of wet scavenging on ambient aerosols in deep, continental convective clouds in the mid-latitudes is studied for a severe storm case in Oklahoma during the Deep Convective Clouds and Chemistry (DC3) field campaign. A new passive-tracer based transport analysis framework is developed to characterize the convective transport based on the vertical distribution of several slowly reacting and nearly insoluble trace gases. The passive gas concentration in the upper troposphere convective outflow results from a mixture of 47% from the lower level (0-3 km), 21% entrained from the upper troposphere, and 32% from mid-atmosphere based on observations. The transport analysis framework is applied to aerosols to estimate aerosol transport and wet-scavenging efficiency. Observations yield high overall scavenging efficiencies of 81% and 68% for aerosol mass (Dp < 1μm) and aerosol number (0.03< Dp < 2.5μm), respectively. Little chemical selectivity to wet scavenging is seen among observed submicron sulfate (84%), organic (82%), and ammonium (80%) aerosols, while nitrate has a much lower scavenging efficiency of 57% likely due to the uptake of nitric acid. Observed larger size particles (0.15 - 2.5μm) are scavenged more efficiently (84%) than smaller particles (64%; 0.03 - 0.15μm). The storm is simulated using the chemistry version of the WRF model. Compared to the observation based analysis, the standard model underestimates the wet scavenging efficiency for both mass and number concentrations with low biases of 31% and 40%, respectively. Adding a new treatment of secondary activation significantly improves simulation results, so that the bias in scavenging efficiency in mass and number concentrations is reduced to <10%. This supports the hypothesis that secondary activation is an important process for wet removal of aerosols in deep convective storms.

  18. Using the OMI aerosol index and absorption aerosol optical depth to evaluate the NASA MERRA Aerosol Reanalysis

    NASA Astrophysics Data System (ADS)

    Buchard, V.; da Silva, A. M.; Colarco, P. R.; Darmenov, A.; Randles, C. A.; Govindaraju, R.; Torres, O.; Campbell, J.; Spurr, R.

    2015-05-01

    A radiative transfer interface has been developed to simulate the UV aerosol index (AI) from the NASA Goddard Earth Observing System version 5 (GEOS-5) aerosol assimilated fields. The purpose of this work is to use the AI and aerosol absorption optical depth (AAOD) derived from the Ozone Monitoring Instrument (OMI) measurements as independent validation for the Modern Era Retrospective analysis for Research and Applications Aerosol Reanalysis (MERRAero). MERRAero is based on a version of the GEOS-5 model that is radiatively coupled to the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) aerosol module and includes assimilation of aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Since AI is dependent on aerosol concentration, optical properties and altitude of the aerosol layer, we make use of complementary observations to fully diagnose the model, including AOD from the Multi-angle Imaging SpectroRadiometer (MISR), aerosol retrievals from the AErosol RObotic NETwork (AERONET) and attenuated backscatter coefficients from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission to ascertain potential misplacement of plume height by the model. By sampling dust, biomass burning and pollution events in 2007 we have compared model-produced AI and AAOD with the corresponding OMI products, identifying regions where the model representation of absorbing aerosols was deficient. As a result of this study over the Saharan dust region, we have obtained a new set of dust aerosol optical properties that retains consistency with the MODIS AOD data that were assimilated, while resulting in better agreement with aerosol absorption measurements from OMI. The analysis conducted over the southern African and South American biomass burning regions indicates that revising the spectrally dependent aerosol absorption properties in the near-UV region improves the modeled-observed AI comparisons

  19. Case studies on aerosol feedback effects in online coupled chemistry-meteorology models during the 2010 Russian fire event

    NASA Astrophysics Data System (ADS)

    Forkel, Renate; Brunner, Dominik; Balzarini, Alessandra; Baró, Rocio; Hirtl, Marcus; Jiménez-Guerrero, Pedro; Jorba, Oriol; Perez, Juan L.; Pirovano, Guido; San Jose, Roberto; Schröder, Wolfram; Werhahn, Johannes; Wolke, Ralf; Žabkar, Rahela

    2015-04-01

    Aerosol particles are known to have an impact on weather and climate directly via radiation and via their impact on cloud formation and subsequent modified optical properties of clouds. Integrated or "online" coupled regional meteorology-chemistry models like WRF-Chem, COSMO-ART, COSMO-Muscat, EnviroHIRLAM, NMMB/BSC-CTM, RAMS/ICLAMS or WRF-CMAQ are able to account for this impact of aerosol on simulated meteorological variables. However, besides of the meteorological situation simulated effects may also depend on model configuration. In order to analyse these effects and to compare their representation in different models currently used in Europe, multi model simulations were performed for two episodes with high aerosol loads as a coordinated exercise of the COST Action ES1004 (EuMetChem). Here we analyze the first of these two case studies, the severe Russian forest fires in summer 2010. Emission data, boundary conditions, simulation strategy and data output format were harmonized as much as possible to maximize the comparability of the results from the different models. The high aerosol emissions during the summer 2010 Russian wildfire episode led to pronounced feedback effects. For example, the direct aerosol effect lowered the summer mean solar radiation by 20 W m-3 and seasonal mean temperature by 0.25 degrees. This might be considered as a lower limit as it must be taken into account that aerosol concentrations were generally underestimated by the WRF-Chem simulations by up to 50%. The high aerosol concentrations emitted from the wildfires over Russia were found to decrease the small amount of precipitation over Russia during this episode by another 10% to 30% when aerosol cloud interactions were taken into account. The focus of the discussion will be on case study results from WRF-Chem and a comparison with results from COSMO-ART, COSMO-Muscat, and NMMB/BSC-CTM.

  20. Dispersion and Transport of Cryptosporidium Oocysts from Fecal Pats under Simulated Rainfall Events

    PubMed Central

    Davies, Cheryl M.; Ferguson, Christobel M.; Kaucner, Christine; Krogh, Martin; Altavilla, Nanda; Deere, Daniel A.; Ashbolt, Nicholas J.

    2004-01-01

    The dispersion and initial transport of Cryptosporidium oocysts from fecal pats were investigated during artificial rainfall events on intact soil blocks (1,500 by 900 by 300 mm). Rainfall events of 55 mm h−1 for 30 min and 25 mm h−1 for 180 min were applied to soil plots with artificial fecal pats seeded with approximately 107 oocysts. The soil plots were divided in two, with one side devoid of vegetation and the other left with natural vegetation cover. Each combination of event intensity and duration, vegetation status, and degree of slope (5° and 10°) was evaluated twice. Generally, a fivefold increase (P < 0.05) in runoff volume was generated on bare soil compared to vegetated soil, and significantly more infiltration, although highly variable, occurred through the vegetated soil blocks (P < 0.05). Runoff volume, event conditions (intensity and duration), vegetation status, degree of slope, and their interactions significantly affected the load of oocysts in the runoff. Surface runoff transported from 100.2 oocysts from vegetated loam soil (25-mm h−1, 180-min event on 10° slope) to up to 104.5 oocysts from unvegetated soil (55-mm h−1, 30-min event on 10° slope) over a 1-m distance. Surface soil samples downhill of the fecal pat contained significantly higher concentrations of oocysts on devegetated blocks than on vegetated blocks. Based on these results, there is a need to account for surface soil vegetation coverage as well as slope and rainfall runoff in future assessments of Cryptosporidium transport and when managing pathogen loads from stock grazing near streams within drinking water watersheds. PMID:14766600

  1. Suspended solids transport: an analysis based on turbidity measurements and event based fully calibrated hydrodynamic models.

    PubMed

    Langeveld, J G; Veldkamp, R G; Clemens, F

    2005-01-01

    Modelling suspended solids transport is a key issue for predicting the pollution load discharged by CSOs. Nonetheless, there is still much debate on the main drivers for suspended solids transport and on the modelling approach to be adopted. Current sewer models provide suspended solids transport models. These models, however, rely upon erosion-deposition criteria developed in fluvial environments, therewith oversimplifying the sewer sediment characteristics. Consequently, the performance of these models is poor from a theoretical point of view. To get an improved understanding of the temporal and spatial variations in suspended solids transport, a measuring network was installed in the sewer system of Loenen in conjunction with a hydraulic measuring network from June through December 2001. During the measuring period, 15 storm events rendered high-quality data on both the hydraulics and the turbidity. For each storm event, a hydrodynamic model was calibrated using the Clemens' method. The conclusion of the paper is that modelling of suspended solids transport has been and will be one of the challenges in the field of urban drainage modelling. A direct relation of either shear stress or flow velocity with turbidity could not be found, likely because of the time varying characteristics of the suspended solids.

  2. MATCH-SALSA - Multi-scale Atmospheric Transport and CHemistry model coupled to the SALSA aerosol microphysics model - Part 1: Model description and evaluation

    NASA Astrophysics Data System (ADS)

    Andersson, C.; Bergström, R.; Bennet, C.; Robertson, L.; Thomas, M.; Korhonen, H.; Lehtinen, K. E. J.; Kokkola, H.

    2015-02-01

    We have implemented the sectional aerosol dynamics model SALSA (Sectional Aerosol module for Large Scale Applications) in the European-scale chemistry-transport model MATCH (Multi-scale Atmospheric Transport and Chemistry). The new model is called MATCH-SALSA. It includes aerosol microphysics, with several formulations for nucleation, wet scavenging and condensation. The model reproduces observed higher particle number concentration (PNC) in central Europe and lower concentrations in remote regions. The modeled PNC size distribution peak occurs at the same or smaller particle size as the observed peak at four measurement sites spread across Europe. Total PNC is underestimated at northern and central European sites and accumulation-mode PNC is underestimated at all investigated sites. The low nucleation rate coefficient used in this study is an important reason for the underestimation. On the other hand, the model performs well for particle mass (including secondary inorganic aerosol components), while elemental and organic carbon concentrations are underestimated at many of the sites. Further development is needed, primarily for treatment of secondary organic aerosol, in terms of biogenic emissions and chemical transformation. Updating the biogenic secondary organic aerosol (SOA) scheme will likely have a large impact on modeled PM2.5 and also affect the model performance for PNC through impacts on nucleation and condensation.

  3. Possible indicators of long-range transport for aerosol emitted from various source regions in Northeast Asia

    NASA Astrophysics Data System (ADS)

    Park, S.; Kim, C.

    2013-12-01

    Air pollutant is affected by both long-range transboundary processes and local air pollution emission. Therefore it is important to identify the origin of air pollutant, for example, by classifying air pollutants into long-range transport (LRT) dominant process and local emission dominant (LED) cases. This study proposed several chemical and physical indicators of LRT process of aerosol concentrations observed at Korean peninsula. In order to identify the source regions and to estimate the contributions of both LRT and LED, we performed Lagrangian particle dispersion model(FLEXPART) and selected high pollution days over the three source regions in China inland and one Korea peninsula defined in this study; LRT-I to III and LED case. Next, we investigated the chemical and physical characteristics of LRT process of aerosol, and contrasted to those in the LED case over the Northeast Asia. We examined the difference of both modeled features simulated by CMAQ and as well measured aerosol optical properties of satellite-based sensor MODIS and AERONET data. Modeling study showed that the most effective indicator is the sulfur conversion ratios such as SO42-/(SO2+ SO42-) and SO42-/ SO2 for high sulfate condition. The ratio of N-containing species such as NOx (or NOy) to CO were the next best alternative indicators. In the meteorological fields, the results showed that pressure pattern and streamline flow are similar on a case by case basis. For observational physical features, we obtained the spatial distributions of the mean AOD, fine mode fraction (FMF), angstrom exponent (AE) by taking the average of MODIS aerosol products for the each analysis period. The highest AOD was found over the industrialized coastal region regardless of cases. AERONET data showed that aerosol size distribution showed significantly higher concentration of fine-mode particle in LED cases in comparison with that of LRT groups, suggesting that the amplitude fine modes of LRT relative to LED could

  4. Comparative stress responses to short transport and related events in Hereford and Brahman steers.

    PubMed

    Browning, R; Leite-Browning, M L

    2013-02-01

    Three summer experiments compared responses to transportation-related events in 2- to 4-yr-old Brahman (Bos indicus) and Hereford (B. taurus) steers. In Exp. 1, steers were hauled round-trip (4 h) or fasted in holding pens. Transport transiently increased (P < 0.01) plasma cortisol and glucose concentrations, decreased (P < 0.05) plasma triglyceride concentrations, and increased total leukocyte counts. Blood constituents were not altered for steers fasting in holding pens. Treatment-day BW shrink was greater (P < 0.01) in transported steers than penned steers. Blood constituent responses were unaffected (P < 0.05) by subspecies. Hereford experienced greater (P < 0.05) transport-day BW shrink than Brahman across treatments. Steers in Exp. 2 were hauled to a new farm for a 1-wk relocation period or hauled round-trip an equal time (0.67 h) and returned to the home station. Both treatments similarly experienced transport-day BW shrink and increased (P < 0.01) plasma cortisol and glucose. Subspecies did not affect (P < 0.05) blood constituent responses to transport. Hereford experienced greater (P < 0.05) transport-day shrink than Brahman. Relocation did not elicit (P < 0.05) changes in blood profiles beyond the day of transport. In Exp. 3, steers were loaded and unloaded without transport, transported round-trip (1 h), or fasted in a holding pen for 3 h. Cortisol increased (P < 0.01) after transport and after loading/unloading. Leukocytes and glucose increased (P < 0.01) after the 1 h transport. Steers transported experienced greater treatment-day BW shrink than those fasted or loaded and unloaded (P < 0.01; -3.13 vs. -1.36 and -0.35 ± 0.76%, respectively). The subspecies did not vary (P < 0.05) for blood constituent responses or shrink in Exp. 3. Animal responses were not evident 24 h after treatments in each experiment. In summary, transport caused stress, but Brahman steers were not more sensitive than Herefords. Hereford steers were susceptible to greater

  5. Study on size distribution of total aerosol and water-soluble ions during an Asian dust storm event at Jeju Island, Korea.

    PubMed

    Park, S H; Song, C B; Kim, M C; Kwon, S B; Lee, K W

    2004-01-01

    Soil dust particles transported from loess regions of the Asian continent, called Asian dust, highly influences the air quality of north-eastern Asia and the northern Pacific Ocean. In order to investigate the effects of these dust storms on the chemical composition of atmospheric aerosol particles with different size, measurements of size distributions of total aerosol and major ion species were carried out on Jeju Island, Korea during April 2001. Juju Island was chosen for the study because the levels of emissions of anthropogenic air pollutants are very low. A 5-stage cascade impactor was used to sample size-fractionated aerosol particles. Samples were analyzed for major water-soluble ions using Dionex DX-120 ion chromatograph. The average mass concentration of total aerosol was found to be 24.4 and 108.3 microg m(-3) for non-Asian dust and Asian dust periods, respectively. The total aerosol size distribution, measured during the non-Asian dust period, was bimodal, whereas the coarse particles dominated the size distribution of total aerosol during the Asian dust period. It was found that SO4(2-), NH4+ and K+ were mainly distributed in fine particles, while Cl-, NO3-, Na+, Mg2+ and Ca2+ were in coarse particles. Although SO4(2-) was mainly distributed in fine particles, during the Asian dust period, the concentrations in coarse particles were significantly increased. This indicates heterogeneous oxidation of SO2 on wet surfaces of basic soil dust particles. The NH4+ was found to exist as (NH4)2SO4 in fine particles, with a molar ratio of NH4+ to SO4(2-) of 2.37 and 1.52 for non-Asian dust and Asian dust periods, respectively. Taking into account the proximity of the sampling site to the sea, and the observed chloride depletion, coarse mode nitrate, during the non-Asian dust period, is assumed to originate from the reaction of nitric acid with sodium chloride on the surfaces of sea-salt particles although the chloride depletion was not shown to be large enough to

  6. Simultaneous analysis of the equilibrium hygroscopicity and water transport kinetics of liquid aerosol.

    PubMed

    Davies, James F; Haddrell, Allen E; Rickards, Andrew M J; Reid, Jonathan P

    2013-06-18

    We demonstrate that the equilibrium hygroscopic response of an aerosol droplet and the kinetics of water condensation and evaporation can be retrieved with high accuracy, even close to saturation, through comparative measurements of probe and sample aerosol droplets. The experimental methodology is described and is based on an electrodynamic balance with a newly designed trapping chamber. Through use of a probe aerosol, composed of either pure water or a sodium chloride solution of known concentration, the gas-phase relative humidity (RH) can be accurately measured with an uncertainty of typically <0.005. By fast manipulation of the airflows into the chamber, a step-change in RH over a time scale of <0.5 s can be achieved. Using this approach, the kinetics of mass transfer are studied using the comparative procedure, and results are compared to theoretical mass flux predictions. The time-dependent measured mass fluxes for sodium chloride, ammonium sulfate, sorbitol, and galactose are used to calculate droplet water activities as a function of the droplet growth factor, allowing retrieval of a hygroscopic growth curve in a matter of seconds. Comparisons with both new and established thermodynamic predictions of hygroscopicity, as well as to optical tweezers measurements, are presented, demonstrating good agreement within the experimental uncertainties. PMID:23662676

  7. Scattering and absorption properties of near-surface aerosol over Gangetic-Himalayan region: the role of boundary layer dynamics and long-range transport

    NASA Astrophysics Data System (ADS)

    Dumka, U. C.; Kaskaoutis, D. G.; Srivastava, M. K.; Devara, P. C. S.

    2014-08-01

    Knowledge of light scattering and absorption properties of atmospheric aerosols is of vital importance in evaluating their types, sources and radiative forcing. This is of particular interest over the Gangetic-Himalayan (GH) region due to large aerosol loading over the plains and the uplift over the Himalayan range causing serious effects on atmospheric heating, glaciology and monsoon circulation. In this respect, Ganges Valley Aerosol Experiment (GVAX) was initiated over the region aiming to examine the aerosol properties, source regions, uplift mechanisms and aerosol-cloud interactions. The present study examines the temporal (monthly, seasonal) evolution of scattering (σsp) and absorption (σap) coefficients, their wavelength dependence, and the role of the Indo-Gangetic plains (IGP), boundary-layer dynamics (BLD) and long-range transport (LRT) in the aerosol uplift over the Himalayas. The measurements are performed at the elevated site Nainital via the Atmospheric Radiation Measurement Mobile Facility including several instruments (Nephelometer, Particle Soot Absorption Photometer, etc.) during June 2011 to March 2012. The σsp and σap exhibit a pronounced seasonal variation with monsoon low and post-monsoon (November) high, while the scattering wavelength exponent exhibits higher values during monsoon, in contrast to the absorption Ångström exponent which maximizes in December-March. The analysis is performed separately for particles bellow 10 and 1μm in diameter in order to examine the influence of the particle size on optical properties. The elevated-background measuring site provides the advantage of examining the LRT of natural and anthropogenic aerosols from the IGP and southwest Asia and the role of BLD in the aerosol lifting processes, while the aerosols are found to be well-mixed and aged-type dominant.

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

    SciTech Connect

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

    2014-08-01

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

  9. Sun photometer aerosol retrievals during SALTRACE

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  10. Evaluate and characterize mechanisms controlling transport, fate, and effects of army smokes in the aerosol wind tunnel: Transport, transformations, fate, and terrestrial ecological effects of hexachloroethane obscurant smokes

    SciTech Connect

    Cataldo, D.A.; Ligotke, M.W.; Bolton, H. Jr.; Fellows, R.J.; Van Voris, P.; McVeety, B.D.; Li, Shu-mei W.; McFadden, K.M.

    1989-09-01

    The terrestrial transport, chemical fate, and ecological effects of hexachloroethane (HC) smoke were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on exposure scenarios, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of HC smoke/obscurants is establishing the importance of environmental parameters such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and two soil types. HC aerosols were generated in a controlled atmosphere wind tunnel by combustion of hexachloroethane mixtures prepared to simulate normal pot burn rates and conditions. The aerosol was characterized and used to expose plant, soil, and other test systems. Particle sizes of airborne HC ranged from 1.3 to 2.1 {mu}m mass median aerodynamic diameter (MMAD), and particle size was affected by relative humidity over a range of 20% to 85%. Air concentrations employed ranged from 130 to 680 mg/m{sup 3}, depending on exposure scenario. Chlorocarbon concentrations within smokes, deposition rates for plant and soil surfaces, and persistence were determined. The fate of principal inorganic species (Zn, Al, and Cl) in a range of soils was assessed.

  11. A case study of a transported bromine explosion event in the Canadian high arctic

    NASA Astrophysics Data System (ADS)

    Zhao, X.; Strong, K.; Adams, C.; Schofield, R.; Yang, X.; Richter, A.; Friess, U.; Blechschmidt, A.-M.; Koo, J.-H.

    2016-01-01

    Ozone depletion events in the polar troposphere have been linked to extremely high concentrations of bromine, known as bromine explosion events (BEE). However, the optimum meteorological conditions for the occurrence of these events remain uncertain. On 4-5 April 2011, a combination of both blowing snow and a stable shallow boundary layer was observed during a BEE at Eureka, Canada (86.4°W, 80.1°N). Measurements made by a Multi-Axis Differential Optical Absorption Spectroscopy spectrometer were used to retrieve BrO profiles and partial columns. During this event, the near-surface BrO volume mixing ratio increased to ~20 parts per trillion by volume, while ozone was depleted to ~1 ppbv from the surface to 700 m. Back trajectories and Global Ozone Monitoring Experiment-2 satellite tropospheric BrO columns confirmed that this event originated from a bromine explosion over the Beaufort Sea. From 30 to 31 March, meteorological data showed high wind speeds (24 m/s) and elevated boundary layer heights (~800 m) over the Beaufort Sea. Long-distance transportation (~1800 km over 5 days) to Eureka indicated strong recycling of BrO within the bromine plume. This event was generally captured by a global chemistry-climate model when a sea-salt bromine source from blowing snow was included. A model sensitivity study indicated that the surface BrO at Eureka was controlled by both local photochemistry and boundary layer dynamics. Comparison of the model results with both ground-based and satellite measurements confirmed that the BEE observed at Eureka was triggered by transport of enhanced BrO from the Beaufort Sea followed by local production/recycling under stable atmospheric shallow boundary layer conditions.

  12. Vertical Profiles of Aerosol Optical and Microphysical Properties During a Rare Case of Long-range Transport of Mixed Biomass Burning-polluted Dust Aerosols from the Russian Federation-kazakhstan to Athens, Greece

    NASA Astrophysics Data System (ADS)

    Papayannis, Alexandros; Argyrouli, Athina; Kokkalis, Panayotis; Tsaknakis, Georgios; Binietoglou, Ioannis; Solomos, Stavros; Kazadzis, Stylianos; Samaras, Stefanos; Böckmann, Christine; Raptis, Panagiotis; Amiridis, Vassilis

    2016-06-01

    Multi-wavelength aerosol Raman lidar measurements with elastic depolarization at 532 nm were combined with sun photometry during the HYGRA-CD campaign over Athens, Greece, on May-June 2014. We retrieved the aerosol optical [3 aerosol backscatter profiles (baer) at 355-532-1064 nm, 2 aerosol extinction (aaer) profiles at 355-532 nm and the aerosol linear depolarization ratio (δ) at 532 nm] and microphysical properties [effective radius (reff), complex refractive index (m), single scattering albedo (ω)]. We present a case study of a long distance transport (~3.500-4.000 km) of biomass burning particles mixed with dust from the Russian Federation-Kazakhstan regions arriving over Athens on 21-23 May 2014 (1.7-3.5 km height). On 23 May, between 2-2.75 km we measured mean lidar ratios (LR) of 35 sr (355 nm) and 42 sr (532 nm), while the mean Ångström exponent (AE) aerosol backscatter-related values (355nm/532nm and 532nm/1064nm) were 2.05 and 1.22, respectively; the mean value of δ at 532 nm was measured to be 9%. For that day the retrieved mean aerosol microphysical properties at 2-2.75 km height were: reff=0.26 μm (fine mode), reff=2.15 μm (coarse mode), m=1.36+0.00024i, ω=0.999 (355 nm, fine mode), ω=0.992(355 nm, coarse mode), ω=0.997 (532 nm, fine mode), and ω=0.980 (532 nm, coarse mode).

  13. Understanding the Role of Water Vapor Transport in Extreme Precipitation Events in Nepal

    NASA Astrophysics Data System (ADS)

    Thapa, K.; Endreny, T. A.; Ferguson, C. R.

    2014-12-01

    In the future, IPCC global climate models project increased frequency of atmospheric rivers (ARs), which are concentrated bands of high moisture known to cause extreme precipitation and flooding events. While ARs have been studied in the United States (US) and Europe using reanalyses and satellite remote sensing, few if any studies have applied an AR analysis framework to regions in South Asia. In this research, we develop and test AR detection algorithms for Nepal by modifying a proven algorithm used in the western US and Europe. Nepal faces challenges in forecasting extreme precipitation events due to the region's complex topography and lack of forecasting infrastructure. Accordingly, any tools that can lead to enhanced lead time of extreme weather forecasts, or help guide water management decisions, will have a substantial positive impact on the region's coping ability. Our AR algorithm uses ERA-Interim reanalysis data to compute integrated water vapor transport (kg m-1s-1) and determine the latitude specific threshold values, for four seasons. After detecting AR events, we test if those events correlate with observed extreme daily precipitation events. Extreme precipitation is determined annually and for non-monsoon months. Our initial results indicate that ARs coincide with extreme precipitation mostly in the cold season. We are extending our analyses to better understand how ARs relate to extreme precipitation events in all seasons. New methods to monitor the role of ARs in precipitation events will help manage water resources, which is critical given the melting of Himalayan glaciers that feed major watersheds of Nepal. In addition to understanding extreme events, our study will also aid in a better understanding of seasonal climate anomalies and the global water cycle.

  14. Characteristics of aerosol types during large-scale transport of air pollution over the Yellow Sea region and at Cheongwon, Korea, in 2008.

    PubMed

    Kim, Hak-Sung; Chung, Yong-Seung; Lee, Sun-Gu

    2012-04-01

    Episodes of large-scale transport of airborne dust and anthropogenic pollutant particles from different sources in the East Asian continent in 2008 were identified by National Oceanic and Atmospheric Administration satellite RGB (red, green, and blue)-composite images and the mass concentrations of ground level particulate matter. These particles were divided into dust, sea salt, smoke plume, and sulfate by an aerosol classification algorithm. To analyze the aerosol size distribution during large-scale transport of atmospheric aerosols, aerosol optical depth (AOD) and fine aerosol weighting (FW) of moderate imaging spectroradiometer aerosol products were used over the East Asian region. Six episodes of massive airborne dust particles, originating from sandstorms in northern China, Mongolia, and the Loess Plateau of China, were observed at Cheongwon. Classified dust aerosol types were distributed on a large-scale over the Yellow Sea region. The average PM10 and PM2.5 ratio to the total mass concentration TSP were 70% and 15%, respectively. However, the mass concentration of PM2.5 among TSP increased to as high as 23% in an episode where dust traveled in by way of an industrial area in eastern China. In the other five episodes of anthropogenic pollutant particles that flowed into the Korean Peninsula from eastern China, the anthropogenic pollutant particles were largely detected in the form of smoke over the Yellow Sea region. The average PM10 and PM2.5 ratios to TSP were 82% and 65%, respectively. The ratio of PM2.5 mass concentrations among TSP varied significantly depending on the origin and pathway of the airborne dust particles. The average AOD for the large-scale transport of anthropogenic pollutant particles in the East Asian region was measured to be 0.42 ± 0.17, which is higher in terms of the rate against atmospheric aerosols as compared with the AOD (0.36 ± 0.13) for airborne dust particles with sandstorms. In particular, the region ranging from eastern

  15. HI-STAR 100 Spent Fuel Transport Cask Analytical Evaluation for Drop Events

    SciTech Connect

    Shah, M. J.; Klymyshyn, Nicholas A.; Adkins, Harold E.; Koeppel, Brian J.

    2007-03-30

    The U.S. Nuclear Regulatory Commission (NRC) is responsible for licensing commercial spent nuclear fuel transported in casks certified by NRC under the Code of Federal Regulations (CFR), Title 10, Part 71 [1]. Both the International Atomic Energy Agency (IAEA) regulations for transporting radioactive materials [2, paragraph 727], and 10 CFR 71.73 require casks to be evaluated for hypothetical accident conditions, which includes a 9-meter (m) (30-ft) drop impact event on a flat, essentially unyielding, horizontal surface, in the most damaging orientation. This paper examines the behavior of one of the NRC-certified transportation casks, the HI-STAR 100 [3], for drop impact events. The specific area examined is the behavior of the bolted connections in the “overpack” top flange and the closure plate, which are significantly loaded during the hypothetical drop impact event. The term “overpack” refers to the cask that receives and contains a sealed multi-purpose canister (MPC) containing spent nuclear fuel. The analytical work to evaluate the NRC-certified HI-STAR 100 spent fuel transport cask [3] for a 9-m (30-ft) drop impact event on a flat, unyielding, horizontal surface, was performed using the ANSYS® [4] and LS DYNA™ [5] finite-element analysis codes. The models were sufficiently detailed, in the areas of bolt closure interfaces and containment boundaries, to evaluate the structural integrity of the bolted connections under 9-m (30-ft) free-drop hypothetical accident conditions, as specified in 10 CFR 71.73. Evaluation of the cask for puncture, caused by a free-drop through a distance of 1-m (40-in.) onto a mild steel bar mounted on a flat, essentially unyielding, horizontal surface, required by 10 CFR 71.73, was not included in the current work, and will have to be addressed in the future. Based on the analyses performed to date, it is concluded that, even though brief separation of the flange and the closure plate surfaces may occur, the seals would

  16. Evaluation of the performance of four chemical transport models in predicting the aerosol chemical composition in Europe in 2005

    NASA Astrophysics Data System (ADS)

    Prank, Marje; Sofiev, Mikhail; Tsyro, Svetlana; Hendriks, Carlijn; Semeena, Valiyaveetil; Vazhappilly Francis, Xavier; Butler, Tim; Denier van der Gon, Hugo; Friedrich, Rainer; Hendricks, Johannes; Kong, Xin; Lawrence, Mark; Righi, Mattia; Samaras, Zissis; Sausen, Robert; Kukkonen, Jaakko; Sokhi, Ranjeet

    2016-05-01

    Four regional chemistry transport models were applied to simulate the concentration and composition of particulate matter (PM) in Europe for 2005 with horizontal resolution ~ 20 km. The modelled concentrations were compared with the measurements of PM chemical composition by the European Monitoring and Evaluation Programme (EMEP) monitoring network. All models systematically underestimated PM10 and PM2.5 by 10-60 %, depending on the model and the season of the year, when the calculated dry PM mass was compared with the measurements. The average water content at laboratory conditions was estimated between 5 and 20 % for PM2.5 and between 10 and 25 % for PM10. For majority of the PM chemical components, the relative underestimation was smaller than it was for total PM, exceptions being the carbonaceous particles and mineral dust. Some species, such as sea salt and NO3-, were overpredicted by the models. There were notable differences between the models' predictions of the seasonal variations of PM, mainly attributable to different treatments or omission of some source categories and aerosol processes. Benzo(a)pyrene concentrations were overestimated by all the models over the whole year. The study stresses the importance of improving the models' skill in simulating mineral dust and carbonaceous compounds, necessity for high-quality emissions from wildland fires, as well as the need for an explicit consideration of aerosol water content in model-measurement comparison.

  17. Bubble bursting as an aerosol generation mechanism during an oil spill in the deep-sea environment: laboratory experimental demonstration of the transport pathway.

    PubMed

    Ehrenhauser, Franz S; Avij, Paria; Shu, Xin; Dugas, Victoria; Woodson, Isaiah; Liyana-Arachchi, Thilanga; Zhang, Zenghui; Hung, Francisco R; Valsaraj, Kalliat T

    2014-01-01

    Oil spills in the deep-sea environment such as the 2010 Deep Water Horizon oil spill in the Gulf of Mexico release vast quantities of crude oil into the sea-surface environment. Various investigators have discussed the marine transport and fate of the oil into different environmental compartments (air, water, sediment, and biota). The transport of the oil into the atmosphere in these previous investigations has been limited to only evaporation, a volatility dependent pathway. In this work, we studied the aerosolization of oil spill matter via bursting bubbles as they occur during whitecaps in a laboratory aerosolization reactor. By evaluating the alkane content in oil mousse, crude oil, the gas phase, and particulate matter we clearly demonstrate that aerosolization via bursting bubbles is a solubility and volatility independent transport pathway for alkanes. The signature of alkane fractions in the native oil and aerosolized matter matched well especially for the less volatile alkanes (C20-C29). Scanning electron microscope interfaced with energy dispersive X-ray images identified the carbon fractions associated with salt particles of aerosols. Theoretical molecular dynamics simulations in the accompanying paper lend support to the observed propensity for alkanes at air-salt water interfaces of breaking bubbles and the produced droplets. The presence of a dispersant in the aqueous phase increased the oil ejection rate at the surface especially for the C20-C29 alkanes. The information presented here emphasizes the need to further study sea-spray aerosols as a possible transport vector for spilled oil in the sea surface environment. PMID:24296745

  18. Sources, seasonality, and trends of Southeast US aerosol: an integrated analysis of surface, aircraft, and satellite observations with the GEOS-Chem chemical transport model

    NASA Astrophysics Data System (ADS)

    Kim, P. S.; Jacob, D. J.; Fisher, J. A.; Travis, K.; Yu, K.; Zhu, L.; Yantosca, R. M.; Sulprizio, M. P.; Jimenez, J. L.; Campuzano-Jost, P.; Froyd, K. D.; Liao, J.; Hair, J. W.; Fenn, M. A.; Butler, C. F.; Wagner, N. L.; Gordon, T. D.; Welti, A.; Wennberg, P. O.; Crounse, J. D.; St. Clair, J. M.; Teng, A. P.; Millet, D. B.; Schwarz, J. P.; Markovic, M. Z.; Perring, A. E.

    2015-07-01

    We use an ensemble of surface (EPA CSN, IMPROVE, SEARCH, AERONET), aircraft (SEAC4RS), and satellite (MODIS, MISR) observations over the Southeast US during the summer-fall of 2013 to better understand aerosol sources in the region and the relationship between surface particulate matter (PM) and aerosol optical depth (AOD). The GEOS-Chem global chemical transport model (CTM) with 25 km × 25 km resolution over North America is used as a common platform to interpret measurements of different aerosol variables made at different times and locations. Sulfate and organic aerosol (OA) are the main contributors to surface PM2.5 (mass concentration of PM finer than 2.5 μm aerodynamic diameter) and AOD over the Southeast US. GEOS-Chem simulation of sulfate requires a missing oxidant, taken here to be stabilized Criegee intermediates, but which could alternatively reflect an unaccounted for heterogeneous process. Biogenic isoprene and monoterpenes account for 60 % of OA, anthropogenic sources for 30 %, and open fires for 10 %. 60 % of total aerosol mass is in the mixed layer below 1.5 km, 20 % in the cloud convective layer at 1.5-3 km, and 20 % in the free troposphere above 3 km. This vertical profile is well captured by GEOS-Chem, arguing against a high-altitude source of OA. The extent of sulfate neutralization (f = [NH4+]/(2[SO42-] + [NO3-])) is only 0.5-0.7 mol mol-1 in the observations, despite an excess of ammonia present, which could reflect suppression of ammonia uptake by organic aerosol. This would explain the long-term decline of ammonium aerosol in the Southeast US, paralleling that of sulfate. The vertical profile of aerosol extinction over the Southeast US follows closely that of aerosol mass. GEOS-Chem reproduces observed total column aerosol mass over the Southeast US within 6 %, column aerosol extinction within 16 %, and space-based AOD within 21 %. The large AOD decline observed from summer to winter is driven by sharp declines in both sulfate and OA from

  19. A HTAP Multi-Model Assessment of the Influence of Regional Anthropogenic Emission Reductions on Aerosol Direct Radiative Forcing and the Role of Intercontinental Transport

    NASA Technical Reports Server (NTRS)

    Yu, Hongbin; Chin, Mian; West, J. Jason; Atherton, Cynthia S.; Bellouin, Nicolas; Bergmann, Dan; Bey, Isabelle; Bian, Huisheng; Diehl, Thomas; Forberth, Gerd; Hess, Peter; Schulz, Michael; Shindell, Drew; Takemura, Toshihiko; Tan, Qian

    2012-01-01

    In this study, we assess changes of aerosol optical depth (AOD) and direct radiative forcing (DRF) in response to the reduction of anthropogenic emissions in four major pollution regions in the northern hemisphere by using results from 10 global chemical transport models in the framework of the Hemispheric Transport of Air Pollution (HTAP). The multi-model results show that on average, a 20% reduction of anthropogenic emissions in North America, Europe, East Asia and South Asia lowers the global mean AOD and DRF by about 9%, 4%, and 10% for sulfate, organic matter, and black carbon aerosol, respectively. The impacts of the regional emission reductions on AOD and DRF extend well beyond the source regions because of intercontinental transport. On an annual basis, intercontinental transport accounts for 10-30% of the overall AOD and DRF in a receptor region, with domestic emissions accounting for the remainder, depending on regions and species. While South Asia is most influenced by import of sulfate aerosol from Europe, North America is most influenced by import of black carbon from East Asia. Results show a large spread among models, highlighting the need to improve aerosol processes in models and evaluate and constrain models with observations.

  20. Event-based stormwater quality and quantity loadings from elevated urban infrastructure affected by transportation.

    PubMed

    Sansalone, John J; Hird, Jonathan P; Cartledge, Frank K; Tittlebaum, Marty E

    2005-01-01

    Urban-rainfall runoff affected by transportation is a complex matrix of a very wide gradation of particulate matter (< 1 to > 10 000 microm) and dissolved inorganic and organic constituents. Particulate matter transported by rainfall runoff can be a significant vector for many reactive particulate-bound constituents, particularly metal elements. The water quality and hydrology of nine events from a representative elevated section of Interstate 10 (I-10) (eastbound average daily traffic load of 70 400 vehicles) in Baton Rouge, Louisiana, were characterized and compared with respect to the passage of each hydrograph. Residence time on the paved concrete surface was less than 30 minutes for all events. Results indicate that event-mean concentrations (EMCs) of particulate matter as total-suspended solids (TSS) (138 to 561 mg/L) and chemical-oxygen demand (COD) (128 to 1440 mg/L) were greater than those found in untreated municipal wastewater from the same service area. Particulate-matter dissolution and COD partitioned as a function of pH, pavement residence time, and organic content. In general, delivery of mass for aggregate indices, such as particulate matter (measured as TSS) and COD mass, were driven by the hydrology of the event, while concentrations of aggregate-constituent measurements, such as total-dissolved solids (TDS), illustrated an exponential-type decline during the rising limb of the hydrograph. Despite the short residence times, wide solids gradation, partitioning, and complexity of the rainfall-runoff chemistry, conductivity and dissolved solids were strongly correlated. Characterization of the transport and loads of constituents in urban-rainfall runoff, as a function of hydrology, is a necessary first step when considering treatability, structural or nonstructural controls, and mass trading for discharges from paved infrastructure. PMID:16121503

  1. A Database of Tornado Events as Perceived by the USArray Transportable Array Network

    NASA Astrophysics Data System (ADS)

    Tytell, J. E.; Vernon, F.; Reyes, J. C.

    2015-12-01

    Over the course of the deployment of Earthscope's USArray Transportable Array (TA) network there have numerous tornado events that have occurred within the changing footprint of its network. The Array Network Facility based in San Diego, California, has compiled a database of these tornado events based on data provided by the NOAA Storm Prediction Center (SPC). The SPC data itself consists of parameters such as start-end point track data for each event, maximum EF intensities, and maximum track widths. Our database is Antelope driven and combines these data from the SPC with detailed station information from the TA network. We are now able to list all available TA stations during any specific tornado event date and also provide a single calculated "nearest" TA station per individual tornado event. We aim to provide this database as a starting resource for those with an interest in investigating tornado signatures within surface pressure and seismic response data. On a larger scale, the database may be of particular interest to the infrasound research community

  2. Role of anthropogenic aerosols in the20th century surface solar radiation, temperature, and meridional heat transport in the Max Planck Earth System Model

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    It is still debated, to what degree anthropogenic aerosols were affected surface temperatures - especially over sea surfaces - through alteration of surface solar radiation (SSR). Previous work using mixed-layer ocean equilibria corroborated the relevance of anthropogenic aerosols for surface temperature response patterns obtained. Here we complement these studies by fully coupled simulations with the Max Planck Earth System Model (MPI-ESM) in its CMIP5 version. Experiments comprise preindustrial control and historical as in CMIP5, as well as transient experiments 1850 - 2000 with either anthropogenic aerosols or well-mixed greenhouse gases (WMGHG) kept at 1850 levels. With this suite of experiments, we analyse the impact of anthropogenic aerosols and WMGHG on the global energy balance and provide estimates of atmospheric and oceanic meridional heat transport changes in our modeling setup. We find that Global mean surface temperature responses to single forcings are additive. Furthermore, spatial surface temperature response patterns in the WMGHG only experiment are more strongly correlated with the historical experiment than the aerosol only case. We compare transient and equilibrium responses and discuss potential implications of not allowing for cloud-aerosol interactions in the transient modeling set-up.

  3. Sediment-transport events on the northern California continental shelf during the 1990-1991 STRESS experiment

    USGS Publications Warehouse

    Sherwood, C.R.; Butman, B.; Cacchione, D.A.; Drake, D.E.; Gross, T.F.; Sternberg, R.W.; Wiberg, P.L.; Williams, A. J.

    1994-01-01

    Measurements of currents and light transmission were made at bottom tripods and moorings arrayed across the northern California continental shelf along the Coastal Ocean Dynamics Experiment (CODE) "C" transect as part of the 1990-1991 Sediment Transport Events on Shelves and Slopes (STRESS) experiment. In combination with meteorological and wave data from the National Data Buoy Center Buoy 46013, these measurements provide information about the physical forcing and resultant resuspension and transport of bottom material between 21 November and 8 March. Sixteen events were identified in the wave, wind and current-meter records for this period. Only two were local storms with southerly winds, but they caused about half of the seasonal net transport. Seven were swell events that combined long-period waves generated by distant storms with local currents. At the 90-m site, swells interacted with the mean northward flow to produce northward transport. During six northerly wind events, upwelling-favorable winds often were sufficient to slow or reverse the mean northward flow and thus caused southward transport. A single current event, which produced moderate southward transport, was observed at the 130-m site. Net transport during the winter experiment was offshore at all sites, northward at the inner- and mid-shelf sites, but southward at the outer-shelf site. The results suggest that local storms with southerly winds may dominate seasonal transport, as on the Washington shelf, but significant transport also can occur during fair weather and during periods of northerly winds. ?? 1994.

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

    SciTech Connect

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

    2008-12-15

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

  5. Applications Of Monte Carlo Radiation Transport Simulation Techniques For Predicting Single Event Effects In Microelectronics

    SciTech Connect

    Warren, Kevin; Reed, Robert; Weller, Robert; Mendenhall, Marcus; Sierawski, Brian; Schrimpf, Ronald

    2011-06-01

    MRED (Monte Carlo Radiative Energy Deposition) is Vanderbilt University's Geant4 application for simulating radiation events in semiconductors. Geant4 is comprised of the best available computational physics models for the transport of radiation through matter. In addition to basic radiation transport physics contained in the Geant4 core, MRED has the capability to track energy loss in tetrahedral geometric objects, includes a cross section biasing and track weighting technique for variance reduction, and additional features relevant to semiconductor device applications. The crucial element of predicting Single Event Upset (SEU) parameters using radiation transport software is the creation of a dosimetry model that accurately approximates the net collected charge at transistor contacts as a function of deposited energy. The dosimetry technique described here is the multiple sensitive volume (MSV) model. It is shown to be a reasonable approximation of the charge collection process and its parameters can be calibrated to experimental measurements of SEU cross sections. The MSV model, within the framework of MRED, is examined for heavy ion and high-energy proton SEU measurements of a static random access memory.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  7. Global aerosol modeling with the online NMMB/BSC Chemical Transport Model: sensitivity to fire injection height prescription and secondary organic aerosol schemes

    NASA Astrophysics Data System (ADS)

    Spada, Michele; Jorba, Oriol; Pérez García-Pando, Carlos; Tsigaridis, Kostas; Soares, Joana; Obiso, Vincenzo; Janjic, Zavisa; Baldasano, Jose M.

    2015-04-01

    We develop and evaluate a fully online-coupled model simulating the life-cycle of the most relevant global aerosols (i.e. mineral dust, sea-salt, black carbon, primary and secondary organic aerosols, and sulfate) and their feedbacks upon atmospheric chemistry and radiative balance. Following the capabilities of its meteorological core, the model has been designed to simulate both global and regional scales with unvaried parameterizations: this allows detailed investigation on the aerosol processes bridging the gap between global and regional models. Since the strong uncertainties affecting aerosol models are often unresponsive to model complexity, we choose to introduce complexity only when it clearly improves results and leads to a better understanding of the simulated aerosol processes. We test two important sources of uncertainty - the fires injection height and secondary organic aerosol (SOA) production - by comparing a baseline simulation with experiments using more advanced approaches. First, injection heights prescribed by Dentener et al. (2006, ACP) are compared with climatological injection heights derived from satellite measurements and produced through the Integrated Monitoring and Modeling System For Wildland Fires (IS4FIRES). Also global patterns of SOA produced by the yield conversion of terpenes as prescribed by Dentener et al. (2006, ACP) are compared with those simulated by the two-product approach of Tsigaridis et al. (2003, ACP). We evaluate our simulations using a variety of observations and measurement techniques. Additionally, we discuss our results in comparison to other global models within AEROCOM and ACCMIP.

  8. Sources, seasonality, and trends of southeast US aerosol: an integrated analysis of surface, aircraft, and satellite observations with the GEOS-Chem chemical transport model

    NASA Astrophysics Data System (ADS)

    Kim, P. S.; Jacob, D. J.; Fisher, J. A.; Travis, K.; Yu, K.; Zhu, L.; Yantosca, R. M.; Sulprizio, M. P.; Jimenez, J. L.; Campuzano-Jost, P.; Froyd, K. D.; Liao, J.; Hair, J. W.; Fenn, M. A.; Butler, C. F.; Wagner, N. L.; Gordon, T. D.; Welti, A.; Wennberg, P. O.; Crounse, J. D.; St. Clair, J. M.; Teng, A. P.; Millet, D. B.; Schwarz, J. P.; Markovic, M. Z.; Perring, A. E.

    2015-09-01

    We use an ensemble of surface (EPA CSN, IMPROVE, SEARCH, AERONET), aircraft (SEAC4RS), and satellite (MODIS, MISR) observations over the southeast US during the summer-fall of 2013 to better understand aerosol sources in the region and the relationship between surface particulate matter (PM) and aerosol optical depth (AOD). The GEOS-Chem global chemical transport model (CTM) with 25 × 25 km2 resolution over North America is used as a common platform to interpret measurements of different aerosol variables made at different times and locations. Sulfate and organic aerosol (OA) are the main contributors to surface PM2.5 (mass concentration of PM finer than 2.5 μm aerodynamic diameter) and AOD over the southeast US. OA is simulated successfully with a simple parameterization, assuming irreversible uptake of low-volatility products of hydrocarbon oxidation. Biogenic isoprene and monoterpenes account for 60 % of OA, anthropogenic sources for 30 %, and open fires for 10 %. 60 % of total aerosol mass is in the mixed layer below 1.5 km, 25 % in the cloud convective layer at 1.5-3 km, and 15 % in the free troposphere above 3 km. This vertical profile is well captured by GEOS-Chem, arguing against a high-altitude source of OA. The extent of sulfate neutralization (f = [NH4+]/(2[SO42-] + [NO3-]) is only 0.5-0.7 mol mol-1 in the observations, despite an excess of ammonia present, which could reflect suppression of ammonia uptake by OA. This would explain the long-term decline of ammonium aerosol in the southeast US, paralleling that of sulfate. The vertical profile of aerosol extinction over the southeast US follows closely that of aerosol mass. GEOS-Chem reproduces observed total column aerosol mass over the southeast US within 6 %, column aerosol extinction within 16 %, and space-based AOD within 8-28 % (consistently biased low). The large AOD decline observed from summer to winter is driven by sharp declines in both sulfate and OA from August to October. These declines

  9. Impacts of the January 2014 extreme rainfall event on transportation network in the Alps Maritimes (France)

    NASA Astrophysics Data System (ADS)

    Voumard, Jeremie; Penna, Ivanna; Jaboyedoff, Michel; Derron, Marc-Henri

    2014-05-01

    Road networks in mountain areas are highly inter-dependent systems, and hillslope processes such as landslides are main drivers of infrastructure detriment and transportation disruptions. Besides the structural damages, economic losses are also related to road and surrounding slope maintenance, as well as due to the disruption of transportation of goods, inaccessibility of tourist resorts, etc. 16-17th January 2014, an intense rainfall event was recorded in the Alpes Maritimes from the southern part of France. According to meteorological data, it was the highest since the 70's. This rainfall triggered numerous landslides (rockfalls, earth flows and debris flows), mostly on January 17th. There were no casualties registered due to hillslope processes, but several houses were damaged, some populations living in the Var valley along the RM 2205 road were isolated, and several roads were partially and totally blocked. 1.5 km upstream the village of Saint-Sauveur-sur-Tinée, 150 m3 of rock detached from the slope and blocked the road, after which temporary traffic interruptions due to road works lasted around one week. In the Menton area, where hillslopes are highly urbanized, the volume of rocks involved in slope failures was so large that materials removed to reestablish the traffic had to be placed in transitory storage sites. The average landslide volume was estimated at around 100 m3. Most of the landslides occurred in slopes cut during road and houses constructions. Several trucks were needed to clean up materials, giving place to traffic jams, etc. (some single events reached around 400 m3). The aim of this study is to document the impact on transportation networks caused by this rainfall event. Damages and consequences for the traffic were documented during a field visit, obtained from secondary information, as well as by the aid of a drone in the case of inaccessible areas.

  10. The impact of interplanetary transport on the charge spectra of heavy ions accelerated in SEP events

    NASA Astrophysics Data System (ADS)

    Kartavykh, J.; Kovaltsov, G.; Ostryakov, V.; Droege, W.

    We investigate the effects of interplanetary propagation on charge spectra of heavy ions observed at 1 AU. A Monte-Carlo approach is applied to solve the transport equation which takes into account spatial diffusion as well as convection and adiabatic deceleration. It is shown that interplanetary propagation results in a shift of charge spectra towards lower energies due to adiabatic deceleration. This fact should be taken into account when experimental data are interpreted. A broadening of charge distributions caused by interplanetary propagation might explain rather wide charge distributions observed in a number of SEP events. We explain the available charge spectra of iron for several impulsive SEP events making use of our model of interplanetary propagation assuming different values of the mean free path.

  11. Aerosol transport and dispersion measurements in the near surface boundary layer

    NASA Astrophysics Data System (ADS)

    Hiscox, April Lynn

    The studies presented in this dissertation present new techniques for measuring aerosols in the atmosphere, and the application of these techniques to three different aerosol sources. A methodology for measuring dispersion parameters based on lidar images, which can be used as an efficient way to remotely monitor time variations of plume dispersion parameters, is presented. Lidar images of a smoke plume cross-section over a forest canopy during nighttime conditions are analyzed to estimate vertical dispersion parameters and vertical meander of the plume centerline in the near field. Dispersion parameters 60 meters downwind are found to have a median value of 2.31 meters. Measurements of these parameters have not previously been made outside the restraints of a wind tunnel experiment. A second technique to measure in-plume concentrations based on single wavelength lidar images is also presented. A field study of aerial spray movement and dispersion was used to determine in-plume spray concentrations of very fine droplets applied during calm, stable atmospheric conditions. Supporting meteorology and air turbulence measurements were made simultaneously with 3-D sonic anemometers. The amount of spray material remaining in the air decreased rapidly for 1--2 minutes, and thereafter remained nearly constant and drifted as a definable plume with the slight air currents. Finally, these two techniques are applied to measure near-field spatial dynamics, spread and concentrations of dust plumes emitted during tilling and harvesting of an irrigated cotton field. Combined lidar images are used to form three-dimensional plumes. Plume dynamics and suspended aerosol concentrations are found. Dust plume dynamics varied with atmospheric stability. In particular, plume maximum height was significantly lower during stable conditions. Plume tracking indicated little change in plume cross-sectional area with height under unstable conditions and plume movement depended on wind speed and

  12. Trans-boundary aerosol transport during a winter haze episode in China revealed by ground-based Lidar and CALIPSO satellite

    NASA Astrophysics Data System (ADS)

    Qin, Kai; Wu, Lixin; Wong, Man Sing; Letu, Husi; Hu, Mingyu; Lang, Hongmei; Sheng, Shijie; Teng, Jiyao; Xiao, Xin; Yuan, Limei

    2016-09-01

    By employing PM2.5 observation data, ground-based lidar measurements, MODIS and CALIPSO satellite images, meteorological data, and back trajectories analysis, we investigate a trans-boundary transport of aerosols during a large-area haze episode in China during 3-5 January 2015. The ground-based lidar observations indicated similar episodes of external aerosols passing through and mixing into three East China cities. A considerable amount of total AOD below 3 km (46% in average) was contributed by the external aerosol layers during passing over and importing. CALIPSO satellite observations of central and eastern China revealed a high altitude pollutant belt on January 3. Although the severest ground pollution was found in central and south-eastern Hebei, the high altitude pollution transport was greater in south-western Shandong, north-western Jiangsu, and north-western Anhui. These observations along with the analysis of air mass trajectories and wind fields indicates pollutants moving from Hebei, Henan and Hubei probably contributed to the haze pollution in Shandong and Jiangsu. This study reveals haze transports from North China Plain to East China could be a common phenomenon influenced by the winter monsoon in northern China. Hence, effective control of air pollution requires collaboration among different cities and provinces throughout China. The long-term measurements of aerosol vertical properties by ground-based lidar and CALIPSO are extremely valuable in quantifying the contributions of external factors and will be helpful in validating and improving various air quality models.

  13. Trans-boundary aerosol transport during a winter haze episode in China revealed by ground-based Lidar and CALIPSO satellite

    NASA Astrophysics Data System (ADS)

    Qin, Kai; Wu, Lixin; Wong, Man Sing; Letu, Husi; Hu, Mingyu; Lang, Hongmei; Sheng, Shijie; Teng, Jiyao; Xiao, Xin; Yuan, Limei

    2016-09-01

    By employing PM2.5 observation data, ground-based lidar measurements, MODIS and CALIPSO satellite images, meteorological data, and back trajectories analysis, we investigate a trans-boundary transport of aerosols during a large-area haze episode in China during 3-5 January 2015. The ground-based lidar observations indicated similar episodes of external aerosols passing through and mixing into three East China cities. A considerable amount of total AOD below 3 km (46% in average) was contributed by the external aerosol layers during passing over and importing. CALIPSO satellite observations of central and eastern China revealed a high altitude pollutant belt on January 3. Although the severest ground pollution was found in central and south-eastern Hebei, the high altitude pollution transport was greater in south-western Shandong, north-western Jiangsu, and north-western Anhui. These observations along with the analysis of air mass trajectories and wind fields indicates pollutants moving from Hebei, Henan and Hubei probably contributed to the haze pollution in Shandong and Jiangsu. This study reveals haze transports from North China Plain to East China could be a common phenomenon influenced by the winter monsoon in northern China. Hence, effective control of air pollution requires collaboration among different cities and provinces throughout China. The long-term measurements of aerosol vertical properties by ground-based lidar and CALIPSO are extremely valuable in quantifying the contributions of external factors and will be helpful in validating and improving various air quality models.

  14. Enrichment behavior and transport mechanism of soil-bound PAHs during rainfall-runoff events.

    PubMed

    Zheng, Yi; Luo, Xiaolin; Zhang, Wei; Wu, Bin; Han, Feng; Lin, Zhongrong; Wang, Xuejun

    2012-12-01

    Polycyclic Aromatic Hydrocarbons (PAHs) transported by surface runoff result in nonpoint source pollution and jeopardize aquatic ecosystems. The transport mechanism of PAHs during rainfall-runoff events has been rarely studied regarding pervious areas. An experimental system was setup to simulate the runoff pollution process on PAHs-contaminated soil. The enrichment behavior of soil-bound PAHs was investigated. The results show that soil organic matters (SOM), rather than clay particles, seem to be the main carrier of PAHs. The enrichment is highly conditioned on runoff and erosion processes, and its magnitude varies among PAH compounds. It is not feasible to build a simple and universal relationship between enrichment ratio and sediment discharge following the traditional enrichment theory. To estimate the flux of PAHs from pervious areas, soil erosion process has to be clearly understood, and both organic carbon content and composition of SOM should be factored into the calculation.

  15. Transport mechanisms of soil-bound mercury in the erosion process during rainfall-runoff events.

    PubMed

    Zheng, Yi; Luo, Xiaolin; Zhang, Wei; Wu, Xin; Zhang, Juan; Han, Feng

    2016-08-01

    Soil contamination by mercury (Hg) is a global environmental issue. In watersheds with a significant soil Hg storage, soil erosion during rainfall-runoff events can result in nonpoint source (NPS) Hg pollution and therefore, can extend its environmental risk from soils to aquatic ecosystems. Nonetheless, transport mechanisms of soil-bound Hg in the erosion process have not been explored directly, and how different fractions of soil organic matter (SOM) impact transport is not fully understood. This study investigated transport mechanisms based on rainfall-runoff simulation experiments. The experiments simulated high-intensity and long-duration rainfall conditions, which can produce significant soil erosion and NPS pollution. The enrichment ratio (ER) of total mercury (THg) was the key variable in exploring the mechanisms. The main study findings include the following: First, the ER-sediment flux relationship for Hg depends on soil composition, and no uniform ER-sediment flux function exists for different soils. Second, depending on soil composition, significantly more Hg could be released from a less polluted soil in the early stage of large rainfall events. Third, the heavy fraction of SOM (i.e., the remnant organic matter coating on mineral particles) has a dominant influence on the enrichment behavior and transport mechanisms of Hg, while clay mineral content exhibits a significant, but indirect, influence. The study results imply that it is critical to quantify the SOM composition in addition to total organic carbon (TOC) for different soils in the watershed to adequately model the NPS pollution of Hg and spatially prioritize management actions in a heterogeneous watershed.

  16. New insights into PM2.5 chemical composition and sources in two major cities in China during extreme haze events using aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Elser, Miriam; Huang, Ru-Jin; Wolf, Robert; Slowik, Jay G.; Wang, Qiyuan; Canonaco, Francesco; Li, Guohui; Bozzetti, Carlo; Daellenbach, Kaspar R.; Huang, Yu; Zhang, Renjian; Li, Zhengqiang; Cao, Junji; Baltensperger, Urs; El-Haddad, Imad; Prévôt, André S. H.

    2016-03-01

    During winter 2013-2014 aerosol mass spectrometer (AMS) measurements were conducted for the first time with a novel PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 µm) lens in two major cities of China: Xi'an and Beijing. We denote the periods with visibility below 2 km as extreme haze and refer to the rest as reference periods. During the measurements in Xi'an an extreme haze covered the city for about a week and the total non-refractory (NR)-PM2.5 mass fraction reached peak concentrations of over 1000 µg m-3. During the measurements in Beijing two extreme haze events occurred, but the temporal extent and the total concentrations reached during these events were lower than in Xi'an. Average PM2.5 concentrations of 537 ± 146 and 243 ± 47 µg m-3 (including NR species and equivalent black carbon, eBC) were recorded during the extreme haze events in Xi'an and Beijing, respectively. During the reference periods the measured average concentrations were 140 ± 99 µg m-3 in Xi'an and 75 ± 61 µg m-3 in Beijing. The relative composition of the NR-PM2.5 evolved substantially during the extreme haze periods, with increased contributions of the inorganic components (mostly sulfate and nitrate). Our results suggest that the high relative humidity present during the extreme haze events had a strong effect on the increase of sulfate mass (via aqueous phase oxidation of sulfur dioxide). Another relevant characteristic of the extreme haze is the size of the measured particles. During the extreme haze events, the AMS showed much larger particles, with a volume weighted mode at about 800 to 1000 nm, in contrast to about 400 nm during reference periods. These large particle sizes made the use of the PM2.5 inlet crucial, especially during the severe haze events, where 39 ± 5 % of the mass would have been lost in the conventional PM1 (particulate matter with aerodynamic diameter ≤ 1 µm) inlet. A novel positive matrix factorization procedure was developed to

  17. New insights into PM2.5 chemical composition and sources in two major cities in China during extreme haze events using aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Elser, M.; Huang, R.-J.; Wolf, R.; Slowik, J. G.; Wang, Q.-Y.; Canonaco, F.; Li, G. H.; Bozzetti, C.; Daellenbach, K. R.; Huang, Y.; Zhang, R.-J.; Li, Z.-Q.; Cao, J. J.; Baltensperger, U.; El-Haddad, I.; Prévôt, A. S. H.

    2015-11-01

    During winter 2013-2014 aerosol mass spectrometer (AMS) measurements were conducted for the first time with a novel PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 μm) lens in two major cities of China: Xi'an and Beijing. We denote the periods with visibility below 2 km as extreme haze and refer to the rest as reference periods. During the measurements in Xi'an an extreme haze covered the city for about a week and the total non-refractory (NR)-PM2.5 mass fraction reached peak concentrations of over 1000 μg m-3. During the measurements in Beijing two extreme haze events occurred, but the temporal extent and the total concentrations reached during these events were lower than in Xi'an. Average PM2.5 concentrations of 537 ± 146 μg m-3 and 243 ± 47 μg m-3 (including NR species and equivalent black carbon, eBC) were recorded during the extreme haze events in Xi'an and Beijing, respectively. During the reference periods the measured average concentrations were 140 ± 99 μg m-3 in Xi'an and 75 ± 61 μg m-3 in Beijing. The relative composition of the NR-PM2.5 evolved substantially during the extreme haze periods, with increased contributions of the inorganic components (mostly sulfate and nitrate). Our results suggest that the high relative humidity present during the extreme haze events had a strong effect on the increase of sulfate mass (via aqueous phase oxidation of sulfur dioxide). Another relevant characteristic of the extreme haze is the size of the measured particles. During the extreme haze events, the AMS showed much larger particles, with a volume weighted mode at about 800 to 1000 nm, in contrast to about 400 nm during reference periods. These large particle sizes made the use of the PM2.5 inlet crucial, especially during the severe haze events, where 39 ± 5 % of the mass would have been lost in the conventional PM1 (particulate matter with aerodynamic diameter ≤ 1 μm) inlet. A novel positive matrix factorization procedure was developed

  18. Energetic Ion Transport and Concomitant Change of the Fusion Reactivity during Reconnection Events in Spherical Tori

    SciTech Connect

    Ya.I. Kolesnichenko; V.V. Lutsenko; R.B. White; Yu.V. Yakovenko

    2004-07-06

    Effects of MHD reconnection events on the beam-plasma fusion reactivity and transport of the beam ions are studied. Based on the analysis of fusion reactivity changes induced by MHD events, the conclusion is drawn that the strong drops of the neutron yield during sawtooth crashes observed in the National Spherical Torus experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)] are associated with both a particle redistribution inside the plasma and a loss of the beam ions. Mechanisms of the energetic ion transport during sawtooth crashes are analyzed, in particular, with the use of the resonance adiabatic invariant derived in this paper. A numerical simulation of the particle motion during a sawtooth crash in NSTX is done with the code OFSEF [Ya. I. Kolesnichenko, et al., Nucl. Fusion 40, 1325 (2000)] extended for a better description of the particle precession. It is shown that the motion of toroidally passing particles in NSTX can become stochastic under the influence of a crash. This stochasticity, as well as the motion along the resonance island, leads to the escape of some particles from the plasma.

  19. Comparison of the transport codes HZETRN, HETC and FLUKA for a solar particle event

    NASA Astrophysics Data System (ADS)

    Heinbockel, John H.; Slaba, Tony C.; Blattnig, Steve R.; Tripathi, Ram K.; Townsend, Lawrence W.; Handler, Thomas; Gabriel, Tony A.; Pinsky, Lawrence S.; Reddell, Brandon; Clowdsley, Martha S.; Singleterry, Robert C.; Norbury, John W.; Badavi, Francis F.; Aghara, Sukesh K.

    2011-03-01

    The protection of astronauts and instrumentation from galactic cosmic rays and solar particle events is one of the primary constraints associated with mission planning in low earth orbit or deep space. To help satisfy this constraint, several computational tools have been developed to analyze the effectiveness of various shielding materials and structures exposed to space radiation. These tools are now being carefully scrutinized through a systematic effort of verification, validation, and uncertainty quantification. In this benchmark study, the deterministic transport code HZETRN is compared to the Monte Carlo transport codes HETC-HEDS and FLUKA for a 30 g/cm2 water target protected by a 20 g/cm2 aluminum shield exposed to a parameterization of the February 1956 solar particle event. Neutron and proton fluences as well as dose and dose equivalent are compared at various depths in the water target. The regions of agreement and disagreement between the three codes are quantified and discussed, and recommendations for future work are given.

  20. Molecular distributions and stable carbon isotopic compositions of dicarboxylic acids and related compounds in aerosols from Sapporo, Japan: Implications for photochemical aging during long-range atmospheric transport

    NASA Astrophysics Data System (ADS)

    Aggarwal, Shankar G.; Kawamura, Kimitaka

    2008-07-01

    Molecular and stable carbon isotopic (δ13C value) compositions of dicarboxylic acids, ketoacids, and dicarbonyls in aerosol samples (i.e., total suspended particles) collected in Sapporo, northern Japan during spring and summer were determined to better understand the photochemical aging of organic aerosols during long-range transport from East Asia and Siberia. Their molecular distributions were characterized by the predominance of oxalic acid (C2) followed by malonic (C3) or occasionally succinic (C4) acids. Concentrations of total diacids ranged from 106-787 ng m-3 with ketoacids (13-81 ng m-3) and dicarbonyls (2.6-28 ng m-3) being less abundant. Water-soluble organic carbon (WSOC) comprised 23-69% of aerosol organic carbon (OC). OC to elemental carbon (EC) ratios were high (3.6-19, mean: 8.7). The ratios of C3/C4 and WSOC/OC did not show significant diurnal changes, suggesting that the Sapporo aerosols were not seriously affected by local photochemical processes and instead they were already aged. δ13C values of the dominant diacids (C2 - C4) ranged from -14.0 to -25.3‰. Largest δ13C values (-14.0 to -22.4‰, mean: -18.8‰) were obtained for C2, whereas smallest values (-25.1 to -31.4‰, mean: -28.1‰) were for azelaic acid (C9). In general, δ13C values of C2 - C4 diacids became less negative with aerosol aging (i.e., WSOC/OC), presumably due to isotopic fractionation during photochemical degradation of diacids. By comparing the δ13C values of diacids in the Sapporo aerosols with different air mass source regions, we suggest that although initial δ13C values of diacids depend on their precursor sources, the enrichment in 13C can be ascribed to aerosol photochemical aging.

  1. Improving the representation of secondary organic aerosol (SOA) in the MOZART-4 global chemical transport model

    NASA Astrophysics Data System (ADS)

    Mahmud, A.; Barsanti, K.

    2013-07-01

    The secondary organic aerosol (SOA) module in the Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) was updated by replacing existing two-product (2p) parameters with those obtained from two-product volatility basis set (2p-VBS) fits (MZ4-C1), and by treating SOA formation from the following additional volatile organic compounds (VOCs): isoprene, propene and lumped alkenes (MZ4-C2). Strong seasonal and spatial variations in global SOA distributions were demonstrated, with significant differences in the predicted concentrations between the base case and updated model simulations. Updates to the model resulted in significant increases in annual average SOA mass concentrations, particularly for the MZ4-C2 simulation in which the additional SOA precursor VOCs were treated. Annual average SOA concentrations predicted by the MZ4-C2 simulation were 1.00 ± 1.04 μg m-3 in South America, 1.57 ± 1.88 μg m-3 in Indonesia, 0.37 ± 0.27 μg m-3 in the USA, and 0.47 ± 0.29 μg m-3 in Europe with corresponding increases of 178, 406, 311 and 292% over the base-case simulation, respectively, primarily due to inclusion of isoprene. The increases in predicted SOA mass concentrations resulted in corresponding increases in SOA contributions to annual average total aerosol optical depth (AOD) by ~ 1-6%. Estimated global SOA production was 5.8, 6.6 and 19.1 Tg yr-1 with corresponding burdens of 0.22, 0.24 and 0.59 Tg for the base-case, MZ4-C1 and MZ4-C2 simulations, respectively. The predicted SOA budgets fell well within reported ranges for comparable modeling studies, 6.7 to 96 Tg yr-1, but were lower than recently reported observationally constrained values, 50 to 380 Tg yr-1. For MZ4-C2, simulated SOA concentrations at the surface also were in reasonable agreement with comparable modeling studies and observations. Total organic aerosol (OA) mass concentrations at the surface, however, were slightly over-predicted in Europe, Amazonian regions and Malaysian Borneo

  2. Improving the representation of secondary organic aerosol (SOA) in the MOZART-4 global chemical transport model

    NASA Astrophysics Data System (ADS)

    Mahmud, A.; Barsanti, K. C.

    2012-12-01

    The secondary organic aerosol (SOA) module in the Model for Ozone and Related chemical Tracers, version 4 (MOZART-4) has been updated by replacing existing two-product (2p) parameters with those obtained from two-product volatility basis set (2p-VBS) fits, and by treating SOA formation from the following volatile organic compounds (VOCs): isoprene, propene and lumped alkenes. Strong seasonal and spatial variations in global SOA distributions were demonstrated, with significant differences in the predicted concentrations between the base-case and updated model versions. The base-case MOZART-4 predicted annual average SOA of 0.36 ± 0.50 μg m-3 in South America, 0.31 ± 0.38 μg m-3 in Indonesia, 0.09 ± 0.05 μg m-3 in the USA, and 0.12 ± 0.07 μg m-3 in Europe. Concentrations from the updated versions of the model showed a~marked increase in annual average SOA. Using the updated set of parameters alone (MZ4-v1) increased annual average SOA by ~8%, ~16%, ~56%, and ~108% from the base-case in South America, Indonesia, USA, and Europe, respectively. Treatment of additional parent VOCs (MZ4-v2) resulted in an even more dramatic increase of ~178-406% in annual average SOA for these regions over the base-case. The increases in predicted SOA concentrations further resulted in increases in corresponding SOA contributions to annual average total aerosol optical depth (AOD) by <1% for MZ4-v1 and ~1-6% for MZ4-v2. Estimated global SOA production was ~6.6 Tg yr-1 and ~19.1 Tg yr-1 with corresponding burdens of ~0.24 Tg and ~0.59 Tg using MZ4-v1 and MZ4-v2, respectively. The SOA budgets predicted in the current study fall well within reported ranges for similar modeling studies, 6.7 to 96 Tg yr-1, but are lower than recently reported observationally-constrained values, 50 to 380 Tg yr-1. With MZ4-v2, simulated SOA concentrations at the surface were also in reasonable agreement with comparable modeling studies and observations. Concentrations of estimated organic aerosol (OA

  3. Investigation of aged aerosols in size-resolved Asian dust storm particles transported from Beijing, China, to Incheon, Korea, using low-Z particle EPMA

    NASA Astrophysics Data System (ADS)

    Geng, H.; Hwang, H.; Liu, X.; Dong, S.; Ro, C.-U.

    2014-04-01

    This is the first study of Asian dust storm (ADS) particles collected in Beijing, China, and Incheon, Korea, during a spring ADS event. Using a seven-stage May impactor and a quantitative electron probe X-ray microanalysis (ED-EPMA, also known as low-Z particle EPMA), we examined the composition and morphology of 4200 aerosol particles at stages 1-6 (with a size cut-off of 16, 8, 4, 2, 1, and 0.5 μm in equivalent aerodynamic diameter, respectively) collected during an ADS event on 28-29 April 2005. The results showed that there were large differences in the chemical compositions between particles in sample S1 collected in Beijing immediately after the peak time of the ADS and in samples S2 and S3, which were collected in Incheon approximately 5 h and 24 h later, respectively. In sample S1, mineral dust particles accounted for more than 88% in relative number abundance at stages 1-5; and organic carbon (OC) and reacted NaCl-containing particles accounted for 24% and 32%, respectively, at stage 6. On the other hand, in samples S2 and S3, in addition to approximately 60% mineral dust, many sea spray aerosol (SSA) particles reacted with airborne SO2 and NOx (accounting for 24% and 14% on average in samples S2 and S3, respectively), often mixed with mineral dust, were encountered at stages 1-5, and (C, N, O, S)-rich particles (likely a mixture of water-soluble organic carbon with (NH4)2SO4 and NH4NO3) were abundantly observed at stage 6 (accounting for 68% and 51% in samples S2 and S3, respectively). This suggests that an accumulation of sea-salt components on individual ADS particles larger than 1 μm in diameter occurred and many secondary aerosols smaller than 1 μm in diameter were formed when the ADS particles passed over the Yellow Sea. In the reacted or aged mineral dust and SSA particles, nitrate-containing and both nitrate- and sulfate-containing species vastly outnumbered the sulfate-containing species, implying that ambient NOx had a greater influence on the

  4. Investigation of aged aerosols in size-resolved Asian dust storm particles transported from Beijing, China to Incheon, Korea using low-Z particle EPMA

    NASA Astrophysics Data System (ADS)

    Geng, H.; Hwang, H. J.; Liu, X.; Dong, S.; Ro, C.-U.

    2013-10-01

    This is the first study of Asian dust storm (ADS) particles collected in Beijing, China and Incheon, Korea during the same spring ADS event. Using a seven-stage May impactor and a quantitative electron probe X-ray microanalysis (ED-EPMA, also known as low-Z particle EPMA), we examined the composition and morphology of 4200 aerosol particles at stages 1-6 (with a size cut-off of 16, 8, 4, 2, 1, and 0.5 μm in equivalent aerodynamic diameter, respectively) collected during an ADS event on 28-29 April 2005. The results showed that there were large differences in the chemical compositions between particles in sample S1 collected in Beijing immediately after the peak time of the ADS and in samples S2 and S3, which were collected in Incheon approximately 5 h and 24 h later, respectively. In sample S1, mineral dust particles accounted for more than 88% in relative number abundance at stages 1-5, and organic carbon (OC) and reacted NaCl-containing particles accounted for 24% and 32%, respectively, at stage 6. On the other hand, in samples S2 and S3, in addition to approximately 60% mineral dust, many sea salt particles reacted with airborne SO2 and NOx, often mixed with mineral dust, were encountered at stages 1-5, and (C, N, O, S)-rich particles (likely a mixture of water-soluble organic carbon with (NH4)2SO4 and NH4NO3) and K-containing particles were abundantly observed at stage 6. This suggests that the secondary aerosols and the internal mixture of mineral dust with sea spray aerosol increased when the ADS particles passed over the Yellow Sea. In the reacted or aged mineral dust and sea salt particles, nitrate-containing and both nitrate- and sulfate-containing species vastly outnumbered the sulfate-containing species, implying that ambient nitrogen oxides had a greater influence on the atmospheric particles during the ADS episode than SO2. In addition to partially- or totally-reacted CaCO3, reacted or aged Mg-containing aluminosilicates (likely including amesite

  5. Aerosol and pollutant transport and their impact on radiative forcing over the tropical Indian Ocean during the January February 1996 pre-INDOEX cruise

    NASA Astrophysics Data System (ADS)

    Krishnamurti, T. N.; Jha, B.; Prospero, J.; Jayaraman, A.; Ramanathan, V.

    1998-11-01

    Measurements of aerosol bulk composition, optical depth, size distribution and the incoming solar radiation flux were carried out over the coastal waters of India, the Arabian sea and the tropical Indian Ocean during a cruise conducted in January 1996. Aerosol concentrations were relatively high throughout much of the cruise, even when the ship was at considerable distances from land. In this paper, we link the observed spatial variations and meridional gradients in the measurements to monsoonal and inter-hemispheric transport across the ITCZ using a high resolution global reanalysis that highlights the winter monsoon. We show that the northeast monsoonal low level flow can transport sulfates, mineral dust and other aerosols from the Indian sub-continent to the ITCZ within 6 7days. These transports result in an increase the aerosol optical depth (AOD) at the equator by as much as 0.2 and a decrease in the solar radiative forcing at the sea surface by about 10 20 Wm-2. The high concentrations of continental aerosols are a result of three factors: strong (about 6 10m/s) near-surface northerly flow; a shallow boundary layer of about 400 to 800 m thick, which traps the pollutants; subsidence, associated with the northeast monsoon, which suppresses rainfall over most of the Arabian sea and thus minimizes the wet removal process. In addition dust can be transported in the middle troposphere from the Arabian desert to the cruise region 4000km away with a transit time of 2 3days. There is strong evidence of interhemispheric transports effected by eddies that wrap around the ITCZ. These eddies bring clean southern hemisphere air to about 10°N in the Indian Ocean and carry polluted continental air into the southern-hemisphere. In this manner, substantial amounts of aerosols and other pollutants can be routinely transported to the southern-hemisphere Indian Ocean during the northeast monsoon. Thus, in order to understand the connection between continental emissions and

  6. 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

  7. Impact of regional transport on the anthropogenic and biogenic secondary organic aerosols in the Los Angeles Basin

    NASA Astrophysics Data System (ADS)

    Heo, Jongbae; de Foy, Benjamin; Olson, Michael R.; Pakbin, Payam; Sioutas, Constantinos; Schauer, James J.

    2015-02-01

    This manuscript explores the role of regional transport on anthropogenic and biogenic secondary organic carbon (SOC) concentrations in ambient fine particulate (PM2.5) organic carbon (OC) in the Los Angeles (LA) Basin. Daily organic molecular markers, water soluble organic carbon (WSOC), OC, and elemental carbon (EC) measurements from May 2009 through April 2010 at a central site in downtown LA, and results from a positive matrix factorization (PMF) analysis of these data, were used to understand the role of regional transport on SOC concentrations. A backward-trajectory analysis, coupled with the measurements and estimated source contributions, were used to evaluate the origins of SOC aerosols. Anthropogenic and biogenic SOC were identified in central LA over the study period, together contributing 40% of the annual average PM2.5 OC mass. There were distinct seasonal variations, with high contributions of anthropogenic SOC in summer, and high contributions of biogenic SOC in spring. The back-trajectory analysis, coupled with daily source contributions of SOC and organic compounds as indicators, allowed us to identify potential source locations and dominant meteorological conditions contributing to elevated SOC at the measurement site. The results show that air mass movements from the Pacific Ocean are associated with higher contributions of anthropogenic SOC to the PM2.5 OC in downtown LA, suggesting that the combination of local meteorological conditions and local anthropogenic emissions led to an increase in the anthropogenic SOC. In contrast, air masses passing over the Central Valley and forested areas where there are biogenic hydrocarbon emissions are closely associated with higher contributions of biogenic SOC in the region. The study emphasizes that higher anthropogenic SOC contributions are due to the combination of local emissions with humidity air from the ocean, and that higher biogenic SOC contributions are impacted by transport of pollutants from

  8. Are anthropogenic aerosols affecting rainfall?

    NASA Astrophysics Data System (ADS)

    Junkermann, Wolfgang; Hacker, Jorg

    2013-04-01

    Modification of cloud microphysics by anthropogenic aerosols is well known since several decades. Whether the underlying processes leads to changes in precipitation is by far less confirmed. Several different factors affect the production of rain in a way that a causality between increasing aerosol load in the atmosphere and a change of annual rainfall is very difficult to confirm. What would be expected as an effect of additional cloud condensation nuclei is a shift in the spatial and temporal rainfall distribution towards a lower number of days with low rain intensity and more frequent or more vigorous single events. In fact such a shift has been observed in several locations worldwide and has been suggested to be caused by increasing aerosol load, however, without further specification of the nature and number of the aerosols involved. Measurements of aerosols which might be important for cloud properties are extremely sparse and no long term monitoring data sets are available up to now. The problem of missing long term aerosol data that could be compared to available long term meteorological data sets can possibly be resolved in certain areas where well characterized large anthropogenic aerosol sources were installed in otherwise pristine areas without significant changes in land use over several decades. We investigated aerosol sources and current aerosol number, size and spatial distributions with airborne measurements in the planetary boundary layer over two regions in Australia that are reported to suffer from extensive drought despite the fact that local to regional scale water vapor in the atmosphere is slowly and constantly increasing. Such an increase of the total water in the planetary boundary layer would imply also an increase in annual precipitation as observed in many other locations elsewhere. The observed decline of rainfall in these areas thus requires a local to regional scale physical process modifying cloud properties in a way that rain

  9. 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

  10. MATCH-SALSA - Multi-scale Atmospheric Transport and CHemistry model coupled to the SALSA aerosol microphysics model - Part 1: Model description and evaluation

    NASA Astrophysics Data System (ADS)

    Andersson, C.; Bergström, R.; Bennet, C.; Robertson, L.; Thomas, M.; Korhonen, H.; Lehtinen, K. E. J.; Kokkola, H.

    2014-05-01

    We have implemented the sectional aerosol dynamics model SALSA in the European scale chemistry-transport model MATCH (Multi-scale Atmospheric Transport and Chemistry). The new model is called MATCH-SALSA. It includes aerosol microphysics, with several formulations for nucleation, wet scavenging and condensation. The model reproduces observed higher particle number concentration (PNC) in central Europe and lower concentrations in remote regions. The model PNC size distribution peak occurs at the same or smaller particle size as the observed peak at five measurement sites spread across Europe. Total PNC is underestimated at Northern and Central European sites and accumulation mode PNC is underestimated at all investigated sites. On the other hand the model performs well for particle mass, including secondary inorganic aerosol components. Elemental and organic carbon concentrations are underestimated at many of the sites. Further development is needed, primarily for treatment of secondary organic aerosol, both in terms of biogenic emissions and chemical transformation, and for nitrogen gas-particle partitioning. Updating the biogenic SOA scheme will likely have a large impact on modeled PM2.5 and also affect the model performance for PNC through impacts on nucleation and condensation. An improved nitrogen partitioning model may also improve the description of condensational growth.

  11. Detection of Saharan dust and biomass burning events using near-real-time intensive aerosol optical properties in the north-western Mediterranean

    NASA Astrophysics Data System (ADS)

    Ealo, Marina; Alastuey, Andrés; Ripoll, Anna; Pérez, Noemí; Cruz Minguillón, María; Querol, Xavier; Pandolfi, Marco

    2016-10-01

    The study of Saharan dust events (SDEs) and biomass burning (BB) emissions are both topics of great scientific interest since they are frequent and important polluting scenarios affecting air quality and climate. The main aim of this work is evaluating the feasibility of using near-real-time in situ aerosol optical measurements for the detection of these atmospheric events in the western Mediterranean Basin (WMB). With this aim, intensive aerosol optical properties (SAE: scattering Ångström exponent, AAE: absorption Ångström exponent, SSAAE: single scattering albedo Ångström exponent and g: asymmetry parameter) were derived from multi-wavelength aerosol light scattering, hemispheric backscattering and absorption measurements performed at regional (Montseny; MSY, 720 m a.s.l.) and continental (Montsec; MSA, 1570 m a.s.l.) background sites in the WMB. A sensitivity study aiming at calibrating the measured intensive optical properties for SDEs and BB detection is presented and discussed. The detection of SDEs by means of the SSAAE parameter and Ångström matrix (made up by SAE and AAE) depended on the altitude of the measurement station and on SDE intensity. At MSA (mountain-top site) SSAAE detected around 85 % of SDEs compared with 50 % at the MSY station, where pollution episodes dominated by fine anthropogenic particles frequently masked the effect of mineral dust on optical properties during less intense SDEs. Furthermore, an interesting feature of SSAAE was its capability to detect the presence of mineral dust after the end of SDEs. Thus, resuspension processes driven by summer regional atmospheric circulations and dry conditions after SDEs favoured the accumulation of mineral dust at regional level having important consequences for air quality. On average, SAE, AAE and g ranged between -0.7 and 1, 1.3 and 2.5 and 0.5 and 0.75 respectively during SDEs. Based on the aethalometer model, BB contribution to equivalent black carbon (BC) accounted for 36 and 40

  12. Soil derived dust as a source of silica: aerosol properties, emissions, deposition, and transport.

    PubMed

    Gillette, D

    1997-01-01

    Quartz is an abundant mineral in wind generated dust throughout the United States. Of the 18.9 million tons of particles smaller than 10 microns (PM10) dust emitted into the atmosphere by the wind, a significant fraction is silica. Transport of some of this silica to populated areas is possible.

  13. Solute transport processes in flow-event-driven stream-aquifer interaction

    NASA Astrophysics Data System (ADS)

    Xie, Yueqing; Cook, Peter G.; Simmons, Craig T.

    2016-07-01

    The interaction between streams and groundwater controls key features of the stream hydrograph and chemograph. Since surface runoff is usually less saline than groundwater, flow events are usually accompanied by declines in stream salinity. In this paper, we use numerical modelling to show that, at any particular monitoring location: (i) the increase in stream stage associated with a flow event will precede the decrease in solute concentration (arrival time lag for solutes); and (ii) the decrease in stream stage following the flow peak will usually precede the subsequent return (increase) in solute concentration (return time lag). Both arrival time lag and return time lag increase with increasing wave duration. However, arrival time lag decreases with increasing wave amplitude, whereas return time lag increases. Furthermore, while arrival time lag is most sensitive to parameters that control river velocity (channel roughness and stream slope), return time lag is most sensitive to groundwater parameters (aquifer hydraulic conductivity, recharge rate, and dispersitivity). Additionally, the absolute magnitude of the decrease in river concentration is sensitive to both river and groundwater parameters. Our simulations also show that in-stream mixing is dominated by wave propagation and bank storage processes, and in-stream dispersion has a relatively minor effect on solute concentrations. This has important implications for spreading of contaminants released to streams. Our work also demonstrates that a high contribution of pre-event water (or groundwater) within the flow hydrograph can be caused by the combination of in-stream and bank storage exchange processes, and does not require transport of pre-event water through the catchment.

  14. Suspended sediment transport at the instantaneous and event time scales in semiarid watersheds of southeastern Arizona, USA

    NASA Astrophysics Data System (ADS)

    Gao, Peng; Nearing, Mark A.; Commons, Michael

    2013-10-01

    We investigated the high variability of suspended sediment transport in 16 watersheds of Walnut Gulch, southeastern Arizona, USA that were distinguished at three spatial scales: the plot (ca. 0.001-0.01 km2), unit-source (ca. 0.01-0.1 km2), and large (ca. 1-150 km2) scales. Event-based data of water discharge and suspended sediment concentration were compiled in variable periods between the 1960s and 2010s. By subjectively distinguishing five different intraevent transport patterns that may be ascribed to a combination of various hydrological and sediment-transport processes, we showed that no single sediment rating curve could be developed for these data. However, at the event temporal scale, event specific sediment yield (SSYe, t/km2) was significantly correlated to event runoff depth (h, mm) for all transport patterns of the watersheds, suggesting that the complexity of suspended sediment transport at the intraevent scale is effectively reduced at the event scale regardless of watershed sizes. Further regression analysis indicated that the SSYe-h relationship can be generally characterized by a proportional model, SSYe = nh where n, is conceptually equivalent to the volume-weighted event mean sediment concentration and is mainly determined by large events. For watersheds dominated by shrub cover, the change of the n value with watershed area was limited and thus may be reasonably regarded as a constant, implying that despite the highly variable suspended sediment concentrations during individual storm events in variable-sized watersheds, the synoptic effect of suspended sediment transport was similar and may be determined by a single value.

  15. Investigating Types and Sources of Organic Aerosol in Rocky Mountain National Park Using Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Schurman, M. I.; Lee, T.; Sun, Y.; Schichtel, B. A.; Kreidenweis, S. M.; Collett, J. L.

    2011-12-01

    The Rocky Mountain Atmospheric Nitrogen and Sulfur Study (RoMANS) focuses on identifying pathways and sources of nitrogen deposition in Rocky Mountain National Park (RMNP). Past work has combined measurements from a range of instrumentation such as annular denuders, PILS-IC, Hi-Vol samplers, and trace gas analyzers. Limited information from early RoMANS campaigns is available regarding organic aerosol. While prior measurements have produced a measure of total organic carbon mass, high time resolution measures of organic aerosol concentration and speciation are lacking. One area of particular interest is characterizing the types, sources, and amounts of organic nitrogen aerosol. Organic nitrogen measurements in RMNP wet deposition reveal a substantial contribution to the total reactive nitrogen deposition budget. In this study an Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed in summer 2010 at RMNP to investigate organic aerosol composition and its temporal variability. The species timeline and diurnal species variations are combined with meteorological data to investigate local transport events and chemistry; transport from the Colorado Front Range urban corridor appears to be more significant for inorganic species than for the overall organic aerosol mass. Considerable variation in organic aerosol concentration is observed (0.5 to 20 μg/m3), with high concentration episodes lasting between hours and two days. High resolution AMS data are analyzed for organic aerosol, including organic nitrogen species that might be expected from local biogenic emissions, agricultural activities, and secondary reaction products of combustion emissions. Positive matrix factorization reveals that semi-volatile oxidized OA, low-volatility oxidized OA, and biomass burning OA comprise most organic mass; the diurnal profile of biomass burning OA peaks at four and nine pm and may arise from local camp fires, while constant concentrations of

  16. Tropospheric Aerosols

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

    uncertainties by "the I-beams". Only an uncertainty range rather than a best estimate is presented for direct aerosol forcing by mineral dust and for indirect aerosol forcing. An assessment of the present level of scientific understanding is indicated at the bottom of the figure (reproduced by permission of Intergovernmental Panel on Climate Change). The importance of atmospheric aerosols to issues of societal concern has motivated much research intended to describe their loading, distribution, and properties and to develop understanding of the controlling processes to address such issues as air pollution, acid deposition, and climate influences of aerosols. However, description based wholly on measurements will inevitably be limited in its spatial and temporal coverage and in the limited characterization of aerosol properties. These limitations are even more serious for predictions of future emissions and provide motivation for concurrent theoretical studies and development of model-based description of atmospheric aerosols.An important long-range goal, which has already been partly realized, is to develop quantitative understanding of the processes that control aerosol loading, composition, and microphysical properties as well as the resultant optical and cloud-nucleating properties. An objective is to incorporate these results into chemical transport models that can be used for predictions. Such models are required, for example, to design approaches to achieve air quality standards and to assess and predict aerosol influences on climate change. Much current research is directed toward enhancing this understanding and to evaluating it by comparison of model results and observations. However, compared to gases, models involving particles are far more complex because of the need to specify additional parameters such as particle sizes and size distributions, compositions as a function of size, particle shapes, and temporal and spatial variations, including reactions that occur

  17. Contribution of regional transport to the black carbon aerosol during winter haze period in Beijing

    NASA Astrophysics Data System (ADS)

    Wang, Qiyuan; Huang, Ru-Jin; Cao, Junji; Tie, Xuexi; Shen, Zhenxing; Zhao, Shuyu; Han, Yongming; Li, Guohui; Li, Zhengqiang; Ni, Haiyan; Zhou, Yaqing; Wang, Meng; Chen, Yang; Su, Xiaoli

    2016-05-01

    The mass concentrations of atmospheric refractory black carbon (rBC), an important absorber of solar radiation, were continuously measured with a single particle soot photometer (SP2) during wintertime haze period to investigate the transport of pollution to Beijing. The average mass concentration of rBC was 6.1 ± 3.9 μg m-3 during hazy periods, which was 4.7 times higher than it during non-hazy periods. Cluster analysis showed that the air parcels arriving at Beijing mainly originated from the northwest, passed through the south and brought the most polluted air to Beijing. Concentration-weighted trajectory analyses indicated that the central North China Plain were the most likely source region for the rBC that impacted Beijing. Furthermore, the Weather Research and Forecasting-Black Carbon model showed that 71.4-82.0% of the rBC at Beijing was from regional transport during the high rBC episodes and that 47.9-56.8% of the rBC can be attributed to sources in the central North China Plain. These results suggest that regional transport from the central North China Plain, rather than local emissions, was a more important source for rBC pollution in Beijing.

  18. Original sounding and drifting balloon-borne measurements in the western Mediterranean with the aerosol counter/sizer LOAC during summer ChArMEx campaigns, with a focus on desert dust events

    NASA Astrophysics Data System (ADS)

    Renard, Jean-Baptiste; Dulac, François; Vignelles, Damien; Jeannot, Matthieu; Verdier, Nicolas; Chazette, Patrick; Crenn, Vincent; Sciare, Jean; Totems, Julien; Durand, Pierre; Barret, Brice; Jambert, Corinne; Mallet, Marc; Menut, Laurent; Mailler, Sylvain; Basart, Sara; Baldasano, José Maria

    2015-04-01

    ) in late July and early August . A number of the 2013 flights were coupled with ozone concentration measurements (see presentation of Gheusi et al. in the same session). LOAC balloons were especially, but not only, dedicated to study the various Saharan dust events that occurred during the campaign. In particular, a series of flights were conducted every 12 hours during the 15-19 June dust event. Forest fire smoke from North America was also sampled in late June over Minorca, as well as anthropogenic polluted layers in various occasions. LOAC data (available from ChArMEx database http://mistrals.sedoo.fr/ChArMEx) are interpreted with the help of coincident lidar, sun photometer remote sensing measurements available in Menorca, and satellite products and air mass trajectories. The sounding flights allow us to determine the vertical extent of the various aerosol layers, and to follow the particle size distribution and the concentration evolution along the vertical. The low altitude drifting balloons, which stayed roughly at constant altitude between 350 and 3330 m up to more than 25 h, allow us to study the time-evolution of the aerosol concentrations in the same air mass. Under both balloon types, LOAC has detected larges particles up to ~30 µm in diameter. The flights drifting within dust layers indicate that there is a relatively stable particle size distribution during transport over the sea, with no clear sedimentation loss of large particles. Aerosol simulations with the CHIMERE and NMMB/§BSC chemistry-transport models are compared to LOAC measurements. Acknowledgements: LOAC was developed with support of the French ANR. Balloon operations were performed by CNES and special acknowledgements are addressed to Gilles Dupouy, Françoise Douchin and collaborators for field operations. Alexis Doerenbacher from Météo-France and Claude Basdevant from Ecole Polytechnique are also acknowledged for their helpful contribution in providing balloon-related forecasts

  19. Original sounding and drifting balloon-borne measurements in the western Mediterranean with the aerosol counter/sizer LOAC during summer ChArMEx campaigns, with a focus on desert dust events

    NASA Astrophysics Data System (ADS)

    Renard, Jean-Baptiste; Dulac, François; Vignelles, Damien; Jeannot, Matthieu; Verdier, Nicolas; Chazette, Patrick; Crenn, Vincent; Sciare, Jean; Totems, Julien; Durand, Pierre; Barret, Brice; Jambert, Corinne; Mallet, Marc; Menut, Laurent; Mailler, Sylvain; Basart, Sara; Baldasano, José Maria

    2015-04-01

    ) in late July and early August . A number of the 2013 flights were coupled with ozone concentration measurements (see presentation of Gheusi et al. in the same session). LOAC balloons were especially, but not only, dedicated to study the various Saharan dust events that occurred during the campaign. In particular, a series of flights were conducted every 12 hours during the 15-19 June dust event. Forest fire smoke from North America was also sampled in late June over Minorca, as well as anthropogenic polluted layers in various occasions. LOAC data (available from ChArMEx database http://mistrals.sedoo.fr/ChArMEx) are interpreted with the help of coincident lidar, sun photometer remote sensing measurements available in Menorca, and satellite products and air mass trajectories. The sounding flights allow us to determine the vertical extent of the various aerosol layers, and to follow the particle size distribution and the concentration evolution along the vertical. The low altitude drifting balloons, which stayed roughly at constant altitude between 350 and 3330 m up to more than 25 h, allow us to study the time-evolution of the aerosol concentrations in the same air mass. Under both balloon types, LOAC has detected larges particles up to ~30 µm in diameter. The flights drifting within dust layers indicate that there is a relatively stable particle size distribution during transport over the sea, with no clear sedimentation loss of large particles. Aerosol simulations with the CHIMERE and NMMB/§BSC chemistry-transport models are compared to LOAC measurements. Acknowledgements: LOAC was developed with support of the French ANR. Balloon operations were performed by CNES and special acknowledgements are addressed to Gilles Dupouy, Françoise Douchin and collaborators for field operations. Alexis Doerenbacher from Météo-France and Claude Basdevant from Ecole Polytechnique are also acknowledged for their helpful contribution in providing balloon-related forecasts

  20. A comparative study of aerosol microphysical properties retrieved from ground-based remote sensing and aircraft in situ measurements during a Saharan dust event

    NASA Astrophysics Data System (ADS)

    José Granados-Muñoz, María; Bravo-Aranda, Juan Antonio; Baumgardner, Darrel; Guerrero-Rascado, Juan Luis; Pérez-Ramírez, Daniel; Navas-Guzmán, Francisco; Veselovskii, Igor; Lyamani, Hassan; Valenzuela, Antonio; José Olmo, Francisco; Titos, Gloria; Andrey, Javier; Chaikovsky, Anatoli; Dubovik, Oleg; Gil-Ojeda, Manuel; Alados-Arboledas, Lucas

    2016-03-01

    In this work we present an analysis of aerosol microphysical properties during a mineral dust event taking advantage of the combination of different state-of-the-art retrieval techniques applied to active and passive remote sensing measurements and the evaluation of some of those techniques using independent data acquired from in situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak at the Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on 27 June 2011. Column-integrated properties are provided by sun- and star-photometry, which allows for a continuous evaluation of the mineral dust optical properties during both day and nighttime. Both the linear estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during nighttime. LIRIC retrievals reveal the presence of dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 µm3 cm-3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in situ measurements. This study presents for the first time a comparison of the total volume concentration retrieved with LIRIC with independent in situ measurements, obtaining agreement within

  1. Carbonaceous and inorganic composition in long-range transported aerosols over northern Japan: Implication for aging of water-soluble organic fraction

    NASA Astrophysics Data System (ADS)

    Aggarwal, Shankar Gopala; Kawamura, Kimitaka

    To better understand the influence of sources and atmospheric processing on aerosol chemical composition, we collected atmospheric particles in Sapporo, northern Japan during spring and early summer 2005 under the air mass transport conditions from Siberia, China and surrounding seas. The aerosols were analyzed for inorganic ions, organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and the major water-soluble organic compound classes (i.e., dicarboxylic acids and sugars). SO 42- is the most abundant inorganic constituent (average 44% of the identified inorganic ion mass) followed by NH 4+ (21%) and NO 3- (13%). Concentrations of OC, EC, and WSOC ranged from 2.0-16, 0.24-2.9, and 0.80-7.9 μg m -3 with a mean of 7.4, 1.0, and 3.1 μg m -3, respectively. High OC/EC ratios (range: 3.6-19, mean: 8.7) were obtained, however WSOC/OC ratios (0.23-0.69, 0.44) do not show any significant diurnal changes. These results suggest that the Sapporo aerosols were already aged, but were not seriously affected by local photochemical processes. Identified water-soluble organic compounds (diacids + sugars) account for <10% of WSOC. Based on some marker species and air mass back trajectory analyses, and using stable carbon isotopic compositions of shorter-chain diacids (i.e., C 2-C 4) as photochemical aging factor of organic aerosols, the present study suggests that a fraction of WSOC in OC is most likely influenced by aerosol aging, although the OC loading in aerosols may be more influenced by their sources and source regions.

  2. Wintertime aerosol characteristics over the Indo-Gangetic Plain (IGP): Impacts of local boundary layer processes and long-range transport

    NASA Astrophysics Data System (ADS)

    Nair, Vijayakumar S.; Moorthy, K. Krishna; Alappattu, Denny P.; Kunhikrishnan, P. K.; George, Susan; Nair, Prabha R.; Babu, S. Suresh; Abish, B.; Satheesh, S. K.; Tripathi, Sachchida Nand; Niranjan, K.; Madhavan, B. L.; Srikant, V.; Dutt, C. B. S.; Badarinath, K. V. S.; Reddy, R. Ramakrishna

    2007-07-01

    The Indo-Gangetic Plain (IGP) encompasses a vast area, (accounting for ˜21% of the land area of India), which is densely populated (accommodating ˜40% of the Indian population). Highly growing economy and population over this region results in a wide range of anthropogenic activities. A large number of thermal power plants (most of them coal fed) are clustered along this region. Despite its importance, detailed investigation of aerosols over this region is sparse. During an intense field campaign of winter 2004, extensive aerosol and atmospheric boundary layer measurements were made from three locations: Kharagpur (KGP), Allahabad (ALB), and Kanpur (KNP), within the IGP. These data are used (1) to understand the regional features of aerosols and BC over the IGP and their interdependencies, (2) to compare it with features at locations lying at far away from the IGP where the conditions are totally different, (3) to delineate the effects of mesoscale processes associated with changes in the local atmospheric boundary layer (ABL), (4) to investigate the effects of long-range transport or moving weather phenomena in modulating the aerosol properties as well as the ABL characteristics, and (5) to examine the changes as the season changes over to spring and summer. Our investigations have revealed very high concentrations of aerosols along the IGP, the average mass concentrations (MT) of total aerosols being in the range 260 to 300 μg m-3 and BC mass concentrations (MB) in the range 20 to 30 μg m-3 (both ˜5 to 8 times higher than the values observed at off-IGP stations) during December 2004. Despite, BC constituted about 10% to the total aerosol mass concentration, a value quite comparable to those observed elsewhere over India for this season. The dynamics of the local atmospheric boundary layer (ABL) as well as changes in local emissions strongly influence the diurnal variations of MT and MB, both being inversely correlated with the mixed layer height (Zi) and the

  3. Detection of volcanic sulfate aerosol with Envisat MIPAS shown for the Kasatochi, Sarychev, and Nabro eruptions

    NASA Astrophysics Data System (ADS)

    Griessbach, Sabine; Hoffmann, Lars; Spang, Reinhold; von Hobe, Marc; Müller, Rolf; Riese, Martin

    2013-04-01

    Stratospheric sulfate aerosol is known to have a strong impact on climate. Transport pathways of sulfur dioxide and sulfate aerosol to the stratosphere are still discussed. It is known that volcanic eruptions can inject significant amounts of sulfur directly into the stratosphere. Most sulfur, however, is injected into the troposphere and only a fraction of it can make its way into the stratosphere. Global and altitude resolved time series of observations are a valuable source of information for sulfur dioxide and sulfate aerosol detection. Here we present a new aerosol detection method for the infrared limb sounder Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and the results for the Kasatochi, Sarychev, and Nabro eruptions. The new detection method utilizes three infrared window regions that are located around 830, 960, and 1224 cm-1. The combination of these three windows allows for a better detection of enhanced aerosol events in the troposphere as well as the discrimination from ice clouds. With this new method the 10 year record of MIPAS measurements was analyzed. The most remarkable sulfate aerosol events follow the Kasatochi, Sarychev, and Nabro eruptions. After these eruptions enhanced aerosol is detected in the upper troposphere and lower stratosphere (UTLS) region. Within one to two months it spreads over most of the northern hemisphere. In the tropics the aerosol reaches altitudes up to around 20 km and in the Arctic up to 15 km. The enhanced aerosol signal can be observed for about 5, 7, and up to 10 month for the Kasatochi, Sarychev, and Nabro eruptions, respectively. During this period the enhanced aerosol detections decrease in number, strength, and observation altitude. After the Nabro eruption on 13 June 2011 volcanic aerosol is detected in the UTLS region two days after the initial eruption. The following days the aerosol moves around the northern edge of the Asian monsoon region, is then transported southwards and later

  4. Impacts of ENSO events on cloud radiative effects in preindustrial conditions: Changes in cloud fraction and their dependence on interactive aerosol emissions and concentrations

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Russell, Lynn M.; Xu, Li; Lou, Sijia; Lamjiri, Maryam A.; Somerville, Richard C. J.; Miller, Arthur J.; Cayan, Daniel R.; DeFlorio, Michael J.; Ghan, Steven J.; Liu, Ying; Singh, Balwinder; Wang, Hailong; Yoon, Jin-Ho; Rasch, Philip J.

    2016-06-01

    We use three 150 year preindustrial simulations of the Community Earth System Model to quantify the impacts of El Niño-Southern Oscillation (ENSO) events on shortwave and longwave cloud radiative effects (CRESW and CRELW). Compared to recent observations from the Clouds and the Earth's Radiant Energy System data set, the model simulation successfully reproduces larger variations of CRESW and CRELW over the tropics. The ENSO cycle is found to dominate interannual variations of cloud radiative effects. Simulated cooling (warming) effects from CRESW (CRELW) are strongest over the tropical western and central Pacific Ocean during warm ENSO events, with the largest difference between 20 and 60 W m-2, with weaker effects of 10-40 W m-2 over Indonesian regions and the subtropical Pacific Ocean. Sensitivity tests show that variations of cloud radiative effects are mainly driven by ENSO-related changes in cloud fraction. The variations in midlevel and high cloud fractions each account for approximately 20-50% of the interannual variations of CRESW over the tropics and almost all of the variations of CRELW between 60°S and 60°N. The variation of low cloud fraction contributes to most of the variations of CRESW over the midlatitude oceans. Variations in natural aerosol concentrations explained 10-30% of the variations of both CRESW and CRELW over the tropical Pacific, Indonesian regions, and the tropical Indian Ocean. Changes in natural aerosol emissions and concentrations enhance 3-5% and 1-3% of the variations of cloud radiative effects averaged over the tropics.

  5. Brown snow: A long-range transport event in the Canadian Arctic

    SciTech Connect

    Welch, H.E.; Muir, D.C.G.; Billeck, B.N.; Lockhart, W.L.; Brunskill, G.J.; Kling, H.J. ); Olson, M.P. ); Lemoine, R.M. )

    1991-02-01

    The authors document the occurrence of a long-range transport event that deposited thousands of tons of fine particulates on the District of Keewatin, central Canadian Arctic, {approximately}63 N. Air mass trajectories, clay mineral composition, soot particles, and visible organic remains point to Asian sources for the brown snow material, probably western China. Semivolatile organic pollutants detected in the brown snow included polycyclic aromatic hydrocarbons ({Sigma}PAH), PCB congeners, and DDT-related compounds ({Sigma}DDT), polychlorinated camphenes (PCCs), as well as the herbicide trifuluralin and insecticides methoxychlor, endosulfan, and hexachlorocyclohexane (HCH). {Sigma}PAH, PCB, and PCC concentrations were within the range reported in other studies of Arctic snow but {Sigma}DDT levels were 2-10 times higher than previous reports. High molecular weight PAH may have been associated with soot particles in the brown snow but evidence for Asian sources of the pesticides was not strong because of unknown source signal strengths and possible atmospheric transformations of the compounds. Fluxes of these pollutants were also determined by analyzing sediment cores from two small headwater lakes near the sampling site. The quantities of pollutants deposited in this single event may have comprised a significant fraction (>10%) of total annual input {Sigma}PAH and {Sigma}DDT, as determined from lake sedimentation records.

  6. Response to comments on "Large volcanic aerosol load in the stratosphere linked to Asian monsoon transport".

    PubMed

    Bourassa, Adam E; Robock, Alan; Randel, William J; Deshler, Terry; Rieger, Landon A; Lloyd, Nicholas D; Llewellyn, E J; Degenstein, Douglas A

    2013-02-01

    Fromm et al. and Vernier et al. suggest that their analyses of satellite measurements indicate that the main part of the Nabro volcanic plume from the eruption on 13 June 2011 was directly injected into the stratosphere. We address these analyses and, in addition, show that both wind trajectories and height-resolved profiles of sulfur dioxide indicate that although the eruption column may have extended higher than the Smithsonian report we highlighted, it was overwhelmingly tropospheric. Additionally, the height-resolved sulfur dioxide profiles provide further convincing evidence for convective transport of volcanic gas to the stratosphere from deep convection associated with the Asian monsoon. PMID:23393248

  7. A numerical study of sediment transport and event bed genesis during tropical strom Delia

    NASA Astrophysics Data System (ADS)

    Keen, Timothy R.; Slingerland, Rudy L.

    1993-03-01

    Some event beds (tempestites) are thought to be emplaced on shallow marine shelves by the combined action of strong coastal currents and high waves during fairly short-lived storms. To test this hypothesis, a storm sedimentation system has been constructed from six numerical models describing a cyclonic wind field, three-dimensional coastal circulation, wind waves generated over the continental shelf, the combined effect of steady and oscillatory currents within the benthic boundary layer, suspended and bed load transport of sediment, and conservation of the seafloor. This model system is used to hindcast winds, currents, waves, and resulting sedimentation during Tropical Storm Delia, which passed over the Texas-Louisiana shelf on September 3-4, 1973. Sensitivity to the initial substrate is investigated in four experiments using uniform silt, uniform sand, a mud line at the 20-m isobath, and a simplified modern sediment distribution. Modeled coastal currents are vertically uniform and do not reveal the structure predicted by the mid-latitude geostrophic storm circulation model, because the predicted depth of the wind-mixed layer is greater than the water depth over the shelf. Shelf currents in excess of 2 m/s flow predominantly along the coast to the southwest during most of the storm, driven by the wind stress and the trapped coastal wave which peaks at 180 cm near Galveston. Significant wave heights reach 8 m on the outer shelf but are less than 4 m over the inner shelf. These waves combine with steady currents to produce bed shear velocities which locally exceed 20 cm/s. The region of highest stresses always lies to the right of the storm track (viewed down the path) and moves across the shelf with the eye of the storm. Three general sediment transport paths are evident: (1) onshore transport of finer sediment over the outer shelf to the right of the storm track, (2) westward-directed along-shelf transport of predominantly fine sediment between approximately 40

  8. On the diurnal cycle of urban aerosols, black carbon and the occurrence of new particle formation events in springtime São Paulo, Brazil

    NASA Astrophysics Data System (ADS)

    Backman, J.; Rizzo, L. V.; Hakala, J.; Nieminen, T.; Manninen, H. E.; Morais, F.; Aalto, P. P.; Siivola, E.; Carbone, S.; Hillamo, R.; Artaxo, P.; Virkkula, A.; Petäjä, T.; Kulmala, M.

    2012-12-01

    Large conurbations are a significant source of the anthropogenic pollution and demographic differences between cities that result in a different pollution burden. The metropolitan area of São Paulo (MASP, population 20 million) accounts for one fifth of the Brazilian vehicular fleet. A feature of MASP is the amount of ethanol used by the vehicular fleet, known to exacerbate air quality. The study describes the diurnal behaviour of the submicron aerosol and relies on total particle number concentration, particle number size distribution, light scattering and light absorption measurements. Modelled planetary boundary layer (PBL) depth and air mass movement data were used to aid the interpretation. During morning rush-hour, stagnant air and a shallow PBL height favour the accumulation of aerosol pollution. During clear-sky conditions, there was a wind shift towards the edge of the city indicating a heat island effect with implications on particulate pollution levels at the site. The median total particle number concentration for the submicron aerosol typically varied in the range 1.6 × 104-3.2 × 104 cm-3 frequently exceeding 4 × 104 cm-3 during the day. During weekdays, nucleation-mode particles are responsible for most of the particles by numbers. The highest concentrations of total particle number concentrations and black carbon (BC) were observed on Fridays. Median diurnal values for light absorption and light scattering (at 637 nm wavelength) varied in the range 12-33 Mm-1 and 21-64 Mm-1, respectively. The former one is equal to 1.8-5.0 μg m-3 of BC. The growth of the PBL, from the morning rush-hour until noon, is consistent with the diurnal cycle of BC mass concentrations. Weekday hourly median single-scattering albedo (ω0) varied in the range 0.59-0.76. Overall, this suggests a top of atmosphere (TOA) warming effect. However, considering the low surface reflectance of urban areas, for the given range of ω0, the TOA radiative forcing can be either positive

  9. Simulations of the Aerosol Index and the Absorption Aerosol Optical Depth and Comparisons with OMI Retrievals During ARCTAS-2008 Campaign

    NASA Technical Reports Server (NTRS)

    2010-01-01

    We have computed the Aerosol Index (AI) at 354 nm, useful for observing the presence of absorbing aerosols in the atmosphere, from aerosol simulations conducted with the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) module running online the GEOS-5 Atmospheric GCM. The model simulates five aerosol types: dust, sea salt, black carbon, organic carbon and sulfate aerosol and can be run in replay or data assimilation modes. In the assimilation mode, information's provided by the space-based MODIS and MISR sensors constrains the model aerosol state. Aerosol optical properties are then derived from the simulated mass concentration and the Al is determined at the OMI footprint using the radiative transfer code VLIDORT. In parallel, model derived Absorption Aerosol Optical Depth (AAOD) is compared with OMI retrievals. We have focused our study during ARCTAS (June - July 2008), a period with a good sampling of dust and biomass burning events. Our ultimate goal is to use OMI measurements as independent validation for our MODIS/MISR assimilation. Towards this goal we document the limitation of OMI aerosol absorption measurements on a global scale, in particular sensitivity to aerosol vertical profile and cloud contamination effects, deriving the appropriate averaging kernels. More specifically, model simulated (full) column integrated AAOD is compared with model derived Al, this way identifying those regions and conditions under which OMI cannot detect absorbing aerosols. Making use of ATrain cloud measurements from MODIS, C1oudSat and CALIPSO we also investigate the global impact on clouds on OMI derived Al, and the extent to which GEOS-5 clouds can offer a first order representation of these effects.

  10. The Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES): An Observational Campaign for Determining Role of Clouds, Aerosols and Radiation in Climate System

    NASA Astrophysics Data System (ADS)

    McFarquhar, G. M.; Wood, R.; Bretherton, C. S.; Alexander, S.; Jakob, C.; Marchand, R.; Protat, A.; Quinn, P.; Siems, S. T.; Weller, R. A.

    2014-12-01

    The Southern Ocean (SO) region is one of the cloudiest on Earth, and as such clouds determine its albedo and play a major role in climate. Evidence shows Earth's climate sensitivity and the Intertropical Convergence Zone location depend upon SO clouds. But, climate models are challenged by uncertainties and biases in the simulation of clouds, aerosols, and air-sea exchanges in this region which trace back to a poor process-level understanding. Due to the SO's remote location, there have been sparse observations of clouds, aerosols, precipitation, radiation and the air-sea interface apart from those from satellites. Plans for an upcoming observational program, SOCRATES, are outlined. Based on feedback on observational and modeling requirements from a 2014 workshop conducted at the University of Washington, a plan is described for obtaining a comprehensive dataset on the boundary-layer structure and associated vertical distributions of liquid and mixed-phase cloud and aerosol properties across a range of synoptic settings, especially in the cold sector of cyclonic storms. Four science themes are developed: improved climate model simulation of SO cloud and boundary layer structure in a rapidly varying synoptic setting; understanding seasonal and synoptic variability in SO cloud condensation and ice nucleus concentration and the role of local biogenic sources; understanding supercooled liquid and mixed-phase clouds and their impacts; and advancing retrievals of clouds, precipitation, aerosols, radiation and surface fluxes. Testable hypotheses for each theme are identified. The observational strategy consists of long-term ground-based observations from Macquarie Island and Davis, continuous data collection onboard Antarctic supply ships, satellite retrievals, and a dedicated field campaign covering 2 distinct seasons using in-situ and remote sensors on low- and high-altitude aircraft, UAVs, and a ship-borne platform. A timeline for these activities is proposed.

  11. Synoptic weather types and long-range transport patterns for ozone precursors during high-ozone events in southern Sweden.

    PubMed

    Tang, Lin; Karlsson, Per Erik; Gu, Yongfeng; Chen, Deliang; Grennfelt, Peringe

    2009-12-01

    We studied long-range transport patterns and related weather types in relation to high-ozone events in southern Sweden. The aim was to deepen the understanding of the relationship between Lamb-Jenkinson weather types and surface ozone concentration variation, thus widening the application of the weather type analysis of air quality at 4 sites in this region. The long-range transport patterns associated with high-ozone events were classified into trajectories from Western Europe, Eastern Europe, and in the vicinity of southern Sweden (VIC). The VIC type, characterized by short and whirling curves, represented more than 40% of the high-ozone events at the studied rural sites. More than half of the high-ozone events occurred under high-pressure conditions, belonging to weather type A (anticyclones). The high correlation coefficient between annual counts of weather type A and those of long-range transport pattern VIC confirmed the strong link between stagnant weather conditions and high-ozone events, especially during the summer. Furthermore, a strong linear anticorrelation was detected between high-ozone events and annual counts of weather type C (cyclones) during the summer. This relationship implies that the frequency of weather type C is a useful indicator for low risk of summertime high-ozone events in southern Sweden. Moreover, the relationship between the weather type and high ozone risk may be useful in examining the potential effect of climate change on the regional air quality.

  12. Transport and Microphysics of Aerosols Released by Collapse and Fire of the World Trade Center on September 11, 2001 as Observed by AERONET and MISR

    NASA Astrophysics Data System (ADS)

    Stenchikov, G. L.; Diner, D.; Kahn, R.; Smirnov, A.; Holben, B.

    2005-12-01

    Atmospheric pollution has been studied intensively during the last several decades for its impact on climate, visibility, atmospheric chemistry, and public health. Here we consider the aftermath of the catastrophic aerosol release produced by the collapse of the World Trade Center (WTC) in New York City (NYC) on September 11, 2001. The north and south WTC buildings were attacked at 0846 EDT and 0903 EDT, respectively, on September 11, 2001. The collapse of the WTC South Tower at 0959 EDT followed by the crash of the North Tower at 1029 EDT instantaneously pulverized a vast amount of building material, that was reduced to dust and smoke in nearby streets and the atmosphere above. The remains of the WTC complex covered a 16-acre area known as Ground Zero. Intensive combustion continued until September 14, with temperatures occasionally exceeding 1000 C, producing a steady, elevated source of hazardous gases and aerosols. A detailed spatial and temporal description of the pollution fields' evolution is needed to fully understand their environmental and health impact, but many existing in situ aerosol monitoring stations in the vicinity of the WTC were completely plugged with dust immediately after the collapse. However, the aerosol plume was remotely sensed from the ground and from space. Here we combine numerical modeling of micrometeorological fields and pollution transport using the RAMS/HYPACT modeling system with AERONET and MISR retrievals, to realistically reconstruct plume evolution. AERONET collected plume data in NYC from the roof of the Goddard Institute for Space Studies (GISS) in Upper Manhattan. In NYC, aerosol optical depth was rather low until 1800 UTC on September 12; then it increased to ~0.3 (at 440 nm) by 2130 UTC. On September 13, the optical depth was slightly elevated in the morning and increased further beginning at 1700 UTC, reaching ~0.30 by 2000-2200 UTC. The angstrom exponent increased from 1.8 on September 12 to 2.2 in the late afternoon

  13. Application of the VH-TDMA technique to coastal ambient aerosols

    NASA Astrophysics Data System (ADS)

    Johnson, G.; Ristovski, Z.; Morawska, L.

    2004-08-01

    A newly developed VH-TDMA has been used for the first time to measure the volatile fractions and post volatilization hygroscopic growth factors of ambient aerosols in the coastal marine and urban environments. The results are compared with comparable data for laboratory generated aerosols of known composition. Measurements conducted on coastal Aitken mode particles showed volatilization behavior similar to laboratory generated aerosols composed of methane sulfonic acid and ammonium sulfate. Measurements conducted on 60 nm particles during nucleation events contained a greater fraction of material with similar volatility to ammonium sulfate than was found at other times. These particles were hygroscopic but less so than pure ammonium sulfate. Measurements conducted in the Brisbane central business district during sea breeze conditions show similar behavior to the coastal aerosol, but with additional low volatility species. This aerosol may originate from urban sources or from marine particles acquiring additional secondary aerosol species during transport.

  14. Impacts of urbanization on nitrogen cycling and aerosol, surface and groundwater transport in semi-arid regions

    NASA Astrophysics Data System (ADS)

    Lohse, K. A.; Gallo, E.; Carlson, M.; Riha, K. M.; Brooks, P. D.; McIntosh, J. C.; Sorooshian, A.; Michalski, G. M.; Meixner, T.

    2011-12-01

    Semi-arid regions are experiencing disproportionate increases in human population and land transformation worldwide, taxing limited water resources and altering nitrogen (N) biogeochemistry. How the redistribution of water and N by urbanization affects semi-arid ecosystems and downstream water quality (e.g. drinking water) is unclear. Understanding these interactions and their feedbacks will be critical for developing science-based management strategies to sustain these limited resources. This is especially true in the US where some of the fastest growing urban areas are in semi-arid ecosystems, where N and water cycles are accelerated, and intimately coupled, and where runoff from urban ecosystems is actively managed to augment a limited water supply to the growing human population. Here we synthesize several ongoing studies from the Tucson Basin in Arizona and examine how increasing urban land cover is altering rainfall-runoff relationships, groundwater recharge, water quality, and long range transport of atmospheric N. Studies across 5 catchments varying in impervious land cover showed that only the least impervious catchment responded to antecedent moisture conditions while hydrologic responses were not statistically related to antecedent rainfall conditions at more impervious sites. Regression models indicated that rainfall depth, imperviousness, and their combined effect control discharge and runoff ratios (p < 0.01, r2 = 0.91 and 0.75, respectively). In contrast, runoff quality was not predictably related to imperviousness or catchment size. Rather, rainfall depth and duration, time since antecedent rainfall, and stream channel characteristics and infrastructure controlled runoff chemistry. Groundwater studies showed nonpoint source contamination of CFCs and associated nitrate in areas of rapid recharge along ephemeral channels. Aerosol measurements indicate that both long-range transport of N and N emissions from Tucson are being transported and deposited

  15. The role of semi-volatile organic compounds in the mesoscale evolution of biomass burning aerosol: a modeling case study of the 2010 mega-fire event in Russia

    NASA Astrophysics Data System (ADS)

    Konovalov, I. B.; Beekmann, M.; Berezin, E. V.; Petetin, H.; Mielonen, T.; Kuznetsova, I. N.; Andreae, M. O.

    2015-12-01

    Chemistry transport models (CTMs) are an indispensable tool for studying and predicting atmospheric and climate effects associated with carbonaceous aerosol from open biomass burning (BB); this type of aerosol is known to contribute significantly to both global radiative forcing and to episodes of air pollution in regions affected by wildfires. Improving model performance requires systematic comparison of simulation results with measurements of BB aerosol and elucidation of possible reasons for discrepancies between them, which, by default, are frequently attributed in the literature to uncertainties in emission data. Based on published laboratory data on the atmospheric evolution of BB aerosol and using the volatility basis set (VBS) framework for organic aerosol modeling, we examined the importance of taking gas-particle partitioning and oxidation of semi-volatile organic compounds (SVOCs) into account in simulations of the mesoscale evolution of smoke plumes from intense wildfires that occurred in western Russia in 2010. Biomass burning emissions of primary aerosol components were constrained with PM10 and CO data from the air pollution monitoring network in the Moscow region. The results of the simulations performed with the CHIMERE CTM were evaluated by considering, in particular, the ratio of smoke-related enhancements in PM10 and CO concentrations (ΔPM10 and ΔCO) measured in Finland (in the city of Kuopio), nearly 1000 km downstream of the fire emission sources. It is found that while the simulations based on a "conventional" approach to BB aerosol modeling (disregarding oxidation of SVOCs and assuming organic aerosol material to be non-volatile) strongly underestimated values of ΔPM10/ΔCO observed in Kuopio (by a factor of 2), employing the "advanced" representation of atmospheric processing of organic aerosol material resulted in bringing the simulations to a much closer agreement with the ground measurements. Furthermore, taking gas

  16. Importance of transboundary transport of biomass burning emissions to regional air quality in Southeast Asia during a high fire event

    NASA Astrophysics Data System (ADS)

    Aouizerats, B.; van der Werf, G. R.; Balasubramanian, R.; Betha, R.

    2015-01-01

    Smoke from biomass and peat burning has a notable impact on ambient air quality and climate in the Southeast Asia (SEA) region. We modeled a large fire-induced haze episode in 2006 stemming mostly from Indonesia using the Weather Research and Forecasting model coupled with chemistry (WRF-Chem). We focused on the evolution of the fire plume composition and its interaction with the urbanized area of the city state of Singapore, and on comparisons of modeled and measured aerosol and carbon monoxide (CO) concentrations. Two simulations were run with WRF-Chem using the complex volatility basis set (VBS) scheme to reproduce primary and secondary aerosol evolution and concentration. The first simulation referred to as WRF-FIRE included anthropogenic, biogenic and biomass burning emissions from the Global Fire Emissions Database (GFED3) while the second simulation referred to as WRF-NOFIRE was run without emissions from biomass burning. To test model performance, we used three independent data sets for comparison including airborne measurements of particulate matter (PM) with a diameter of 10 μm or less (PM10) in Singapore, CO measurements in Sumatra, and aerosol optical depth (AOD) column observations from four satellite-based sensors. We found reasonable agreement between the model runs and both ground-based measurements of CO and PM10. The comparison with AOD was less favorable and indicated the model underestimated AOD, although the degree of mismatch varied between different satellite data sets. During our study period, forest and peat fires in Sumatra were the main cause of enhanced aerosol concentrations from regional transport over Singapore. Analysis of the biomass burning plume showed high concentrations of primary organic aerosols (POA) with values up to 600 μg m-3 over the fire locations. The concentration of POA remained quite stable within the plume between the main burning region and Singapore while the secondary organic aerosol (SOA) concentration

  17. Aerosol typing - key information from aerosol studies

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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