WorldWideScience

Sample records for surface aerosol measurements

  1. Surface aerosol measurements at Barrow during AGASP

    International Nuclear Information System (INIS)

    Bodhaine, B.A.; Dutton, E.G.; DeLuisi, J.J.

    1984-01-01

    Surface aerosol measurements were made at the Barrow GMCC Observatory during the AGASP flight series in March 1983. The condensation nucleus, scattering extinction coefficient, size distribution, and total aerosol optical depth measurements all clearly show conditions of background Arctic haze for March 9-11, a series of haze episodes during March 12-16, and a return to background haze for March 17-18. Angstrom exponents calculated from scattering coefficient data were low during March 9-11, relatively higher during March 12-14, and highest during March 15-18. Surface aerosol data and aerosol optical depth data are in good qualitative agreement for the 10-day period studied. Background haze was present when trajectories circled the Arctic basin, and haze episodes occurred when trajectories originated in western Asia and Europe

  2. Earth System Research Laboratory Long-Term Surface Aerosol Measurements

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Aerosol measurements began at the NOAA Earth System Research Laboratory (ESRL) Global Monitoring Division (GMD) baseline observatories in the mid-1970's with the...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-04-01

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

  4. Study of measurement methods of ultrafine aerosols surface-area for characterizing occupational exposure

    International Nuclear Information System (INIS)

    Bau, S.

    2008-12-01

    This work aims at improving knowledge on ultrafine aerosols surface-area measurement. Indeed, the development of nano-technologies may lead to occupational exposure to airborne nano-structured particles, which involves a new prevention issue. There is currently no consensus concerning what parameter (mass, surface-area, number) should be measured. However, surface-area could be a relevant metric, since it leads to a satisfying correlation with biological effects when nano-structured particles are inhaled. Hence, an original theoretical work was performed to position the parameter of surface-area in relation to other aerosol characteristics. To investigate measurement techniques of nano-structured aerosols surface-area, the experimental facility CAIMAN (Characterization of Instruments for the Measurement of Aerosols of Nano-particles) was designed and built. Within CAIMAN, it is possible to produce nano-structured aerosols with varying and controlled properties (size, concentration, chemical nature, morphology, state-of-charge), stable and reproducible in time. The generated aerosols were used to experimentally characterize the response of the instruments in study (NSAM and AeroTrak 9000 TSI, LQ1-DC Matter Engineering). The response functions measured with monodisperse aerosols show a good agreement with the corresponding theoretical curves in a large size range, from 15 to 520 nm. Furthermore, hypotheses have been formulated to explain the reasonable biases observed when measuring poly-disperse aerosols. (author)

  5. Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation) at Thessaloniki, Greece

    OpenAIRE

    Lindfors, A. V.; Kouremeti, N.; Arola, A.; Kazadzis, S.; Bais, A. F.; Laaksonen, A.

    2013-01-01

    Pyranometer measurements of the solar surface radiation (SSR) are available at many locations worldwide, often as long time series covering several decades into the past. These data constitute a potential source of information on the atmospheric aerosol load. Here, we present a method for estimating the aerosol optical depth (AOD) using pyranometer measurements of the SSR together with total water vapor column information. The method, which is based on radiative transfer simulations, w...

  6. Vertical profiles of aerosol optical properties over central Illinois and comparison with surface and satellite measurements

    Directory of Open Access Journals (Sweden)

    P. J. Sheridan

    2012-12-01

    Full Text Available Between June 2006 and September 2009, an instrumented light aircraft measured over 400 vertical profiles of aerosol and trace gas properties over eastern and central Illinois. The primary objectives of this program were to (1 measure the in situ aerosol properties and determine their vertical and temporal variability and (2 relate these aircraft measurements to concurrent surface and satellite measurements. The primary profile location was within 15 km of the NOAA/ESRL surface aerosol monitoring station near Bondville, Illinois. Identical instruments at the surface and on the aircraft ensured that the data from both platforms would be directly comparable and permitted a determination of how representative surface aerosol properties were of the lower column. Aircraft profiles were also conducted occasionally at two other nearby locations to increase the frequency of A-Train satellite underflights for the purpose of comparing in situ and satellite-retrieved aerosol data. Measurements of aerosol properties conducted at low relative humidity over the Bondville site compare well with the analogous surface aerosol data and do not indicate any major sampling issues or that the aerosol is radically different at the surface compared with the lowest flyby altitude of ~ 240 m above ground level. Statistical analyses of the in situ vertical profile data indicate that aerosol light scattering and absorption (related to aerosol amount decreases substantially with increasing altitude. Parameters related to the nature of the aerosol (e.g., single-scattering albedo, Ångström exponent, etc., however, are relatively constant throughout the mixed layer, and do not vary as much as the aerosol amount throughout the profile. While individual profiles often showed more variability, the median in situ single-scattering albedo was 0.93–0.95 for all sampled altitudes. Several parameters (e.g., submicrometer scattering fraction, hemispheric backscattering fraction, and

  7. Vertical Profiles of Aerosol Optical Properties Over Central Illinois and Comparison with Surface and Satellite Measurements

    Science.gov (United States)

    Sheridan P. J.; Andrews, E.; Ogren, J A.; Tackett, J. L.; Winker, D. M.

    2012-01-01

    Between June 2006 and September 2009, an instrumented light aircraft measured over 400 vertical profiles of aerosol and trace gas properties over eastern and central Illinois. The primary objectives of this program were to (1) measure the in situ aerosol properties and determine their vertical and temporal variability and (2) relate these aircraft measurements to concurrent surface and satellite measurements. Underflights of the CALIPSO satellite show reasonable agreement in a majority of retrieved profiles between aircraft-measured extinction at 532 nm (adjusted to ambient relative humidity) and CALIPSO-retrieved extinction, and suggest that routine aircraft profiling programs can be used to better understand and validate satellite retrieval algorithms. CALIPSO tended to overestimate the aerosol extinction at this location in some boundary layer flight segments when scattered or broken clouds were present, which could be related to problems with CALIPSO cloud screening methods. The in situ aircraft-collected aerosol data suggest extinction thresholds for the likelihood of aerosol layers being detected by the CALIOP lidar. These statistical data offer guidance as to the likelihood of CALIPSO's ability to retrieve aerosol extinction at various locations around the globe.

  8. Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation at Thessaloniki, Greece

    Directory of Open Access Journals (Sweden)

    A. V. Lindfors

    2013-04-01

    Full Text Available Pyranometer measurements of the solar surface radiation (SSR are available at many locations worldwide, often as long time series covering several decades into the past. These data constitute a potential source of information on the atmospheric aerosol load. Here, we present a method for estimating the aerosol optical depth (AOD using pyranometer measurements of the SSR together with total water vapor column information. The method, which is based on radiative transfer simulations, was developed and tested using recent data from Thessaloniki, Greece. The effective AOD calculated using this method was found to agree well with co-located AERONET measurements, exhibiting a correlation coefficient of 0.9 with 2/3 of the data found within ±20% or ±0.05 of the AERONET AOD. This is similar to the performance of current satellite aerosol methods. Differences in the AOD as compared to AERONET can be explained by variations in the aerosol properties of the atmosphere that are not accounted for in the idealized settings used in the radiative transfer simulations, such as variations in the single scattering albedo and Ångström exponent. Furthermore, the method is sensitive to calibration offsets between the radiative transfer simulations and the pyranometer SSR. The method provides an opportunity of extending our knowledge of the atmospheric aerosol load to locations and times not covered by dedicated aerosol measurements.

  9. Retrieval and Validation of aerosol optical properties from AHI measurements: impact of surface reflectance assumption

    Science.gov (United States)

    Lim, H.; Choi, M.; Kim, J.; Go, S.; Chan, P.; Kasai, Y.

    2017-12-01

    This study attempts to retrieve the aerosol optical properties (AOPs) based on the spectral matching method, with using three visible and one near infrared channels (470, 510, 640, 860nm). This method requires the preparation of look-up table (LUT) approach based on the radiative transfer modeling. Cloud detection is one of the most important processes for guaranteed quality of AOPs. Since the AHI has several infrared channels, which are very advantageous for cloud detection, clouds can be removed by using brightness temperature difference (BTD) and spatial variability test. The Yonsei Aerosol Retrieval (YAER) algorithm is basically utilized on a dark surface, therefore a bright surface (e.g., desert, snow) should be removed first. Then we consider the characteristics of the reflectance of land and ocean surface using three visible channels. The known surface reflectivity problem in high latitude area can be solved in this algorithm by selecting appropriate channels through improving tests. On the other hand, we retrieved the AOPs by obtaining the visible surface reflectance using NIR to normalized difference vegetation index short wave infrared (NDVIswir) relationship. ESR tends to underestimate urban and cropland area, we improved the visible surface reflectance considering urban effect. In this version, ocean surface reflectance is using the new cox and munk method which considers ocean bidirectional reflectance distribution function (BRDF). Input of this method has wind speed, chlorophyll, salinity and so on. Based on validation results with the sun-photometer measurement in AErosol Robotic NETwork (AERONET), we confirm that the quality of Aerosol Optical Depth (AOD) from the YAER algorithm is comparable to the product from the Japan Aerospace Exploration Agency (JAXA) retrieval algorithm. Our future update includes a consideration of improvement land surface reflectance by hybrid approach, and non-spherical aerosols. This will improve the quality of YAER

  10. Comparison of diffusion charging and mobility-based methods for measurement of aerosol agglomerate surface area.

    Science.gov (United States)

    Ku, Bon Ki; Kulkarni, Pramod

    2012-05-01

    We compare different approaches to measure surface area of aerosol agglomerates. The objective was to compare field methods, such as mobility and diffusion charging based approaches, with laboratory approach, such as Brunauer, Emmett, Teller (BET) method used for bulk powder samples. To allow intercomparison of various surface area measurements, we defined 'geometric surface area' of agglomerates (assuming agglomerates are made up of ideal spheres), and compared various surface area measurements to the geometric surface area. Four different approaches for measuring surface area of agglomerate particles in the size range of 60-350 nm were compared using (i) diffusion charging-based sensors from three different manufacturers, (ii) mobility diameter of an agglomerate, (iii) mobility diameter of an agglomerate assuming a linear chain morphology with uniform primary particle size, and (iv) surface area estimation based on tandem mobility-mass measurement and microscopy. Our results indicate that the tandem mobility-mass measurement, which can be applied directly to airborne particles unlike the BET method, agrees well with the BET method. It was also shown that the three diffusion charging-based surface area measurements of silver agglomerates were similar within a factor of 2 and were lower than those obtained from the tandem mobility-mass and microscopy method by a factor of 3-10 in the size range studied. Surface area estimated using the mobility diameter depended on the structure or morphology of the agglomerate with significant underestimation at high fractal dimensions approaching 3.

  11. Surface pressure retrieval from SCIAMACHY measurements in the O2 A Band: validation of the measurements and sensitivity on aerosols

    Directory of Open Access Journals (Sweden)

    B. van Diedenhoven

    2005-01-01

    Full Text Available We perform surface pressure retrievals from cloud-free Oxygen A band measurements of SCIAMACHY. These retrievals can be well validated because surface pressure is a quantity that is, in general, accurately known from meteorological models. Therefore, surface pressure retrievals and their validation provide important insight into the quality of the instrument calibration. Furthermore, they can provide insight into retrievals which are affected by similar radiation transport processes, for example the retrieval of total columns of H2O, CO, CO2 and CH4. In our retrieval aerosols are neglected. Using synthetic measurements, it is shown that for low to moderate surface albedos this leads to an underestimation of the retrieved surface pressures. For high surface albedos this generally leads to an overestimation of the retrieved surface pressures. The surface pressures retrieved from the SCIAMACHY measurements indeed show this dependence on surface albedo, when compared to the corresponding pressures from a meteorological database. However, an offset of about 20 hPa was found, which can not be caused by neglecting aerosols in the retrieval. The same offset was found when comparing the retrieved surface pressures to those retrieved from co-located GOME Oxygen A band measurements. This implies a calibration error in the SCIAMACHY measurements. By adding an offset of 0.86% of the continuum reflectance at 756 nm to the SCIAMACHY reflectance measurements, this systematic bias vanishes.

  12. AEROSOL AND GAS MEASUREMENT

    Science.gov (United States)

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

  13. Error sources in the retrieval of aerosol information over bright surfaces from satellite measurements in the oxygen A band

    Science.gov (United States)

    Nanda, Swadhin; de Graaf, Martin; Sneep, Maarten; de Haan, Johan F.; Stammes, Piet; Sanders, Abram F. J.; Tuinder, Olaf; Pepijn Veefkind, J.; Levelt, Pieternel F.

    2018-01-01

    Retrieving aerosol optical thickness and aerosol layer height over a bright surface from measured top-of-atmosphere reflectance spectrum in the oxygen A band is known to be challenging, often resulting in large errors. In certain atmospheric conditions and viewing geometries, a loss of sensitivity to aerosol optical thickness has been reported in the literature. This loss of sensitivity has been attributed to a phenomenon known as critical surface albedo regime, which is a range of surface albedos for which the top-of-atmosphere reflectance has minimal sensitivity to aerosol optical thickness. This paper extends the concept of critical surface albedo for aerosol layer height retrievals in the oxygen A band, and discusses its implications. The underlying physics are introduced by analysing the top-of-atmosphere reflectance spectrum as a sum of atmospheric path contribution and surface contribution, obtained using a radiative transfer model. Furthermore, error analysis of an aerosol layer height retrieval algorithm is conducted over dark and bright surfaces to show the dependence on surface reflectance. The analysis shows that the derivative with respect to aerosol layer height of the atmospheric path contribution to the top-of-atmosphere reflectance is opposite in sign to that of the surface contribution - an increase in surface brightness results in a decrease in information content. In the case of aerosol optical thickness, these derivatives are anti-correlated, leading to large retrieval errors in high surface albedo regimes. The consequence of this anti-correlation is demonstrated with measured spectra in the oxygen A band from the GOME-2 instrument on board the Metop-A satellite over the 2010 Russian wildfires incident.

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

    Science.gov (United States)

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

    2010-01-01

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

  15. Aerosol Direct Radiative Forcing and Forcing Efficiencies at Surface from the shortwave Irradiance Measurements in Abu Dhabi, UAE

    Science.gov (United States)

    Beegum S, N.; Ben Romdhane, H.; Ghedira, H.

    2013-12-01

    Atmospheric aerosols are known to affect the radiation balance of the Earth-Atmospheric system directly by scattering and absorbing the solar and terrestrial radiation, and indirectly by affecting the lifetime and albedo of the clouds. Continuous and simultaneous measurements of short wave global irradiance in combination with synchronous spectral aerosol optical depth (AOD) measurements (from 340 nm to 1640 nm in 8 channels), for a period of 1 year from June 2012 to May 2013, were used for the determination of the surface direct aerosol radiative forcing and forcing efficiencies under cloud free conditions in Abu Dhabi (24.42°N, 54.61o E, 7m MSL), a coastal location in United Arab Emirates (UAE) in the Arabian Peninsula. The Rotating Shadow band Pyranometer (RSP, LI-COR) was used for the irradiance measurements (in the spectral region 400-1100 nm), whereas the AOD measurements were carried out using CIMEL Sunphotometer (CE 318-2, under AERONET program). The differential method, which is neither sensitive to calibration uncertainties nor model assumptions, has been employed for estimating forcing efficiencies from the changes in the measured fluxes. The forcing efficiency, which quantifies the net change in irradiance per unit change in AOD, is an appropriate parameter for the characterization of the aerosol radiative effects even if the microphysical and optical properties of the aerosols are not completely understood. The corresponding forcing values were estimated from the forcing efficiencies. The estimated radiative forcing and forcing efficiencies exhibited strong monthly variations. The forcing efficiencies (absolute magnitudes) were highest during March, and showed continuous decrease thereafter to reach the lowest value during September. In contrast, the forcing followed a slightly different pattern of variability, with the highest solar dimming during April ( -60 W m-2) and the minimum during February ( -20 W m-2). The results indicate that the aerosol

  16. Chemical and optical properties of atmospheric aerosols in Phimai, Thailand by intensive surface measurements and satellite data analysis

    Science.gov (United States)

    Tsuruta, H.; Thana, B.; Takamura, T.; Hashimoto, M.; Yabuki, M.; Oikawa, E.; Nakajima, T.

    2013-12-01

    Atmospheric aerosols were measured at the Observatory of Atmospheric Research, in Phimai, Thailand, a key station of SKYNET, during 2006-2008. In the surface measurement, mass concentrations and major chemical components in fine and coarse aerosols were analyzed, and the optical properties such as AOT and SSA were measured by skyradiometer. Analysis of MODIS and CALIPSO satellite data was made for wild fire activities and aerosol distribution, respectively. In this paper, the following topics are summarized. The surface wind pattern in dry season was divided into the three periods as follows; D1 (Oct.-Nov.) with northeasterly monsoon, D3 (middle March-April) with southerly wind, and D2 (Dec.-early March) with a transit stage between D1 and D3. Wet season in southwesterly monsoon was from May to September. The concentration ratio of BC/nss-SO4 showed that the dominant PM2.5 aerosols in D1 were due to long-range transport of air pollutants emitted from urban/industrial area of east Asia. In contrast, most of aerosols in D3 were derived from biomass burning in Indochina, because the activity of biomass burning was highest in the latter D2 and early D3 period, by the analysis of the fire database in MODIS and of BC/nss-SO4. The mass concentration in PM2.5 showed a clear seasonal variation with the maximum in D2. On the contrary, AOT showed the maximum in D3, and which could be attributed to an increase in the vertical thickness of high aerosol concentration in the boundary layer by the CALIOP data analysis. Dust particles in D1 were directly transported from east Asia, and re-suspension of soil dusts was dominant in D2 because the surface soil became dry. In D3, soil dusts were re-suspended with the thermal plume caused by biomass burning. In contrast, high dust particles measured in the wet season was due to long range transport of dust aerosols from western desert area by the CALIOP data analysis.

  17. Stratospheric Aerosol Measurements

    Science.gov (United States)

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

    1998-01-01

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

  18. Preliminary analysis of columnar aerosol properties in relation to surface PM measurements in the DAMOCLES 2006 field campaign (Spain)

    Science.gov (United States)

    Estelles, V.; Esteve, A.; Pey, J.; Martinez-Lozano, J. A.; Utrillas, M. P.; Querol, X.; de La Rosa, J.; Gonzalez-Castanedo, Y.; Alastuey, A.; Gangoiti, G.

    2009-04-01

    The DAMOCLES network is a Spanish thematic network, started in 2004, whose main objective is the establishment of a link among the different groups that perform research on atmospheric aerosols in Spain. Under the DAMOCLES coordination, a field campaign was held in summer 2006 at the INTA installations (El Arenosillo, Huelva) for the intercomparison of different kind of instruments devoted to in - situ and columnar aerosol measurement. During this field campaign, two daily meteorological soundings were carried out at noon and midnight for characterization of the atmospheric condition. A plane was also flown by the National Institute of Aerospace Technology (INTA) to carry airborne sensors for measuring different atmospheric factors: meteorological parameters, ozone with a 2BTech analyzer, and aerosol particle size distributions in the range (0.01-2) microns, by using a PCASP probe. The columnar aerosol properties were measured by seven CIMEL CE318 sun photometers. For in situ aerosol characterization, high volume collectors (DIGITEL and MCV) with DIGITEL for PM10, PM2.5 and PM1 measurement were used, with two cascade impactors for particulate matter measurement in 7 -8 granulometric fractions. For the PM10, PM2.5 and PM1 measurement, quartz fibre filters of 150 mm diameter were adapted. Other in situ deployed instruments were a Scanning Mobility Particle Sizer (SMPS, Model 3936), two Aerodynamic Particle Sizer (APS Model 3321) and one Grimm Spectrometer (Model #190). For characterization of the aerosol scattering at ground level, three integrating nephelometers TSI-3563 were used. For the columnar profiling we deployed five LIDAR instruments. In this study we have related the columnar aerosol measurements retrieved with one CE318 sun photometer to the surface PM measurements, mainly in some interesting situations where nearby pollution sources were influencing the local atmosphere. For the sun photometric analysis, we have applied the EuroSkyRad package (ESR

  19. Impacts of Aerosol Direct Effects on the South Asian climate: Assessment of Radiative Feedback Processes Using Model Simulations and Satellite/surface Measurements

    Science.gov (United States)

    Wang, S.; Gautam, R.; Lau, W. K.; Tsay, S.; Sun, W.; Kim, K.; Chern, J.; Colarco, P. R.; Hsu, N. C.; Lin, N.

    2011-12-01

    Current assessment of aerosol radiative effect is hindered by our incomplete knowledge of aerosol optical properties, especially absorption, and our current inability to quantify physical and microphysical processes. In this research, we investigate direct aerosol radiative effect over heavy aerosol loading areas (e.g., Indo-Gangetic Plains, South/East Asia) and its feedbacks on the South Asian climate during the pre-monsoon season (March-June) using the Purdue Regional Climate Model (PRCM) with prescribed aerosol data derived by the NASA Goddard Earth Observing System Model (GEOS-5). Our modeling domain covers South and East Asia (60-140E and 0-50N) with spatial resolutions of 45 km in horizontal and 28 layers in vertical. The model is integrated from 15 February to 30 June 2008 continuously without nudging (i.e., only forced by initial/boundary conditions). Two numerical experiments are conducted with and without the aerosol-radiation effects. Both simulations are successful in reproducing the synoptic patterns on seasonal-to-interannual time scales and capturing a pre-monsoon feature of the northward rainfall propagation over Indian region in early June which shown in Tropical Rainfall Measuring Mission (TRMM) observation. Preliminary result suggests aerosol-radiation interactions mainly alter surface-atmosphere energetics and further result in an adjustment of the vertical temperature distribution in lower atmosphere (below 700 hPa). The modifications of temperature and associated rainfall and circulation feedbacks on the regional climate will be discussed in the presentation. In addition to modeling study, we will also present the most recent results on aerosol properties, regional aerosol absorption, and radiative forcing estimation based on NASA's operational satellite and ground-based remote sensing. Observational results show spatial gradients in aerosol loading and solar absorption accounting over Indo-Gangetic Plains during the pre-monsoon season. The

  20. Gradient flux measurements of sea–air DMS transfer during the Surface Ocean Aerosol Production (SOAP experiment

    Directory of Open Access Journals (Sweden)

    M. J. Smith

    2018-04-01

    Full Text Available Direct measurements of marine dimethylsulfide (DMS fluxes are sparse, particularly in the Southern Ocean. The Surface Ocean Aerosol Production (SOAP voyage in February–March 2012 examined the distribution and flux of DMS in a biologically active frontal system in the southwest Pacific Ocean. Three distinct phytoplankton blooms were studied with oceanic DMS concentrations as high as 25 nmol L−1. Measurements of DMS fluxes were made using two independent methods: the eddy covariance (EC technique using atmospheric pressure chemical ionization–mass spectrometry (API-CIMS and the gradient flux (GF technique from an autonomous catamaran platform. Catamaran flux measurements are relatively unaffected by airflow distortion and are made close to the water surface, where gas gradients are largest. Flux measurements were complemented by near-surface hydrographic measurements to elucidate physical factors influencing DMS emission. Individual DMS fluxes derived by EC showed significant scatter and, at times, consistent departures from the Coupled Ocean–Atmosphere Response Experiment gas transfer algorithm (COAREG. A direct comparison between the two flux methods was carried out to separate instrumental effects from environmental effects and showed good agreement with a regression slope of 0.96 (r2 = 0.89. A period of abnormal downward atmospheric heat flux enhanced near-surface ocean stratification and reduced turbulent exchange, during which GF and EC transfer velocities showed good agreement but modelled COAREG values were significantly higher. The transfer velocity derived from near-surface ocean turbulence measurements on a spar buoy compared well with the COAREG model in general but showed less variation. This first direct comparison between EC and GF fluxes of DMS provides confidence in compilation of flux estimates from both techniques, as well as in the stable periods when the observations are not well predicted by the COAREG

  1. Gradient flux measurements of sea-air DMS transfer during the Surface Ocean Aerosol Production (SOAP) experiment

    Science.gov (United States)

    Smith, Murray J.; Walker, Carolyn F.; Bell, Thomas G.; Harvey, Mike J.; Saltzman, Eric S.; Law, Cliff S.

    2018-04-01

    Direct measurements of marine dimethylsulfide (DMS) fluxes are sparse, particularly in the Southern Ocean. The Surface Ocean Aerosol Production (SOAP) voyage in February-March 2012 examined the distribution and flux of DMS in a biologically active frontal system in the southwest Pacific Ocean. Three distinct phytoplankton blooms were studied with oceanic DMS concentrations as high as 25 nmol L-1. Measurements of DMS fluxes were made using two independent methods: the eddy covariance (EC) technique using atmospheric pressure chemical ionization-mass spectrometry (API-CIMS) and the gradient flux (GF) technique from an autonomous catamaran platform. Catamaran flux measurements are relatively unaffected by airflow distortion and are made close to the water surface, where gas gradients are largest. Flux measurements were complemented by near-surface hydrographic measurements to elucidate physical factors influencing DMS emission. Individual DMS fluxes derived by EC showed significant scatter and, at times, consistent departures from the Coupled Ocean-Atmosphere Response Experiment gas transfer algorithm (COAREG). A direct comparison between the two flux methods was carried out to separate instrumental effects from environmental effects and showed good agreement with a regression slope of 0.96 (r2 = 0.89). A period of abnormal downward atmospheric heat flux enhanced near-surface ocean stratification and reduced turbulent exchange, during which GF and EC transfer velocities showed good agreement but modelled COAREG values were significantly higher. The transfer velocity derived from near-surface ocean turbulence measurements on a spar buoy compared well with the COAREG model in general but showed less variation. This first direct comparison between EC and GF fluxes of DMS provides confidence in compilation of flux estimates from both techniques, as well as in the stable periods when the observations are not well predicted by the COAREG model.

  2. Measurements of dry deposition rates of 212Pb from aerosols on various natural and artificial surfaces

    International Nuclear Information System (INIS)

    Osaki, S.; Sugihara, S.; Maeda, Y.; Osaki, T.

    2007-01-01

    The dry deposition rates on various grass fields and two forests have been measured by the use of 212 Pb (T 1/2 = 10.6 hours). The deposition rate on grass fields (average: 7 mm x s -1 ) roughly depends on the logarithms of the heights or densities of the grasses. The dry deposition rates on a broadleaved forest (Lithocarpus edulis) and a coniferous forest (Cryptomeria Japonica) were also measured. The highest (ave. 26 mm x s -1 ) was on the forest of C. Japonica because of the dense and adhesive surfaces of the leaves. (author)

  3. Impacts of Aerosol Direct Effects on the South Asian Climate: Assessment of Radiative Feedback Processes Using Model Simulations and Satellite/Surface Measurements

    Science.gov (United States)

    Wang, Sheng-Hsiang; Gautam, Ritesh; Lau, William K. M.; Tsay, Si-Chee; Sun, Wen-Yih; Kim, Kyu-Myong; Chern, Jiun-Dar; Hsu, Christina; Lin, Neng-Huei

    2011-01-01

    Current assessment of aerosol radiative effect is hindered by our incomplete knowledge of aerosol optical properties, especially absorption, and our current inability to quantify physical and microphysical processes. In this research, we investigate direct aerosol radiative effect over heavy aerosol loading areas (e.g., Indo-Gangetic Plains, South/East Asia) and its feedbacks on the South Asian climate during the pre-monsoon season (March-June) using the Purdue Regional Climate Model (PRCM) with prescribed aerosol data derived by the NASA Goddard Earth Observing System Model (GEOS-5). Our modeling domain covers South and East Asia (60-140E and 0-50N) with spatial resolutions of 45 km in horizontal and 28 layers in vertical. The model is integrated from 15 February to 30 June 2008 continuously without nudging (i.e., only forced by initial/boundary conditions). Two numerical experiments are conducted with and without the aerosol-radiation effects. Both simulations are successful in reproducing the synoptic patterns on seasonal-to-interannual time scales and capturing a pre-monsoon feature of the northward rainfall propagation over Indian region in early June which shown in Tropical Rainfall Measuring Mission (TRMM) observation. Preliminary result suggests aerosol-radiation interactions mainly alter surface-atmosphere energetics and further result in an adjustment of the vertical temperature distribution in lower atmosphere (below 700 hPa). The modifications of temperature and associated rainfall and circulation feedbacks on the regional climate will be discussed in the presentation.

  4. Satellite Remote Sensing: Aerosol Measurements

    Science.gov (United States)

    Kahn, Ralph A.

    2013-01-01

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

  5. Airborne Atmospheric Aerosol Measurement System

    Science.gov (United States)

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

    2015-12-01

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

  6. Assessment of 1D and 3D model simulated radiation flux based on surface measurements and estimation of aerosol forcing and their climatological aspects

    Science.gov (United States)

    Subba, T.; Gogoi, M. M.; Pathak, B.; Ajay, P.; Bhuyan, P. K.; Solmon, F.

    2018-05-01

    Ground reaching solar radiation flux was simulated using a 1-dimensional radiative transfer (SBDART) and a 3-dimensional regional climate (RegCM 4.4) model and their seasonality against simultaneous surface measurements carried out using a CNR4 net Radiometer over a sub-Himalayan foothill site of south-east Asia was assessed for the period from March 2013-January 2015. The model simulated incoming fluxes showed a very good correlation with the measured values with correlation coefficient R2 0.97. The mean bias errors between these two varied from -40 W m-2 to +7 W m-2 with an overestimation of 2-3% by SBDART and an underestimation of 2-9% by RegCM. Collocated measurements of the optical parameters of aerosols indicated a reduction in atmospheric transmission path by 20% due to aerosol load in the atmosphere when compared with the aerosol free atmospheric condition. Estimation of aerosol radiative forcing efficiency (ARFE) indicated that the presence of black carbon (BC, 10-15%) led to a surface dimming by -26.14 W m-2 τ-1 and a potential atmospheric forcing of +43.04 W m-2 τ-1. BC alone is responsible for >70% influence with a major role in building up of forcing efficiency of +55.69 W m-2 τ-1 (composite) in the atmosphere. On the other hand, the scattering due to aerosols enhance the outgoing radiation at the top of the atmosphere (ARFETOA -12.60 W m-2 ω-1), the absence of which would have resulted in ARFETOA of +16.91 W m-2 τ-1 (due to BC alone). As a result, 3/4 of the radiation absorption in the atmosphere is ascribed to the presence of BC. This translated to an atmospheric heating rate of 1.0 K day-1, with 0.3 K day-1 heating over the elevated regions (2-4 km) of the atmosphere, especially during pre-monsoon season. Comparison of the satellite (MODIS) derived and ground based estimates of surface albedo showed seasonal difference in their magnitudes (R2 0.98 during retreating monsoon and winter; 0.65 during pre-monsoon and monsoon), indicating that the

  7. Aerosol Absorption Measurements in MILAGRO.

    Science.gov (United States)

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

    2007-12-01

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

  8. The aerosol distribution in Europe derived with the Community Multiscale Air Quality (CMAQ) model: comparison to near surface in situ and sunphotometer measurements

    OpenAIRE

    Matthias , V.

    2008-01-01

    The aerosol distribution in Europe was simulated with the Community Multiscale Air Quality (CMAQ) model system version 4.5 for the years 2000 and 2001. The results were compared with daily averages of PM10 measurements taken in the framework of EMEP and with aerosol optical depth (AOD) values measured within AERONET. The modelled total aerosol mass is typically about 30–60% lower than the corresponding measurements. However a comparison of the chemical composition of th...

  9. A comprehensive evaluation of water uptake on atmospherically relevant mineral surfaces: DRIFT spectroscopy, thermogravimetric analysis and aerosol growth measurements

    Directory of Open Access Journals (Sweden)

    R. J. Gustafsson

    2005-01-01

    Full Text Available The hygroscopicity of mineral aerosol samples has been examined by three independent methods: diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis and differential mobility analysis. All three methods allow an evaluation of the water coverage of two samples, CaCO3 and Arizona Test dust, as a function of relative humidity. For the first time, a correlation between absolute gravimetric measurements and the other two (indirect methods has been established. Water uptake isotherms were reliably determined for both solids which at 298 K and 80% relative humidity exhibited similar coverages of ~4 monolayers. However, the behaviour at low relative humidity was markedly different in the two cases, with Arizona Test Dust showing a substantially higher affinity for water in the contact layer. This is understandable in terms of the chemical composition of these two materials. The mobility analysis results are in good accord with field observations and with our own spectroscopic and gravimetric measurements. These findings are of value for an understanding of atmospheric chemical processes.

  10. Importance of Raman Lidar Aerosol Extinction Measurements for Aerosol-Cloud Interaction Studies

    Directory of Open Access Journals (Sweden)

    Han Zaw

    2016-01-01

    Full Text Available Using a UV Raman Lidar for aerosol extinction, and combining Microwave Radiometer derived Liquid Water Path (LWP with Multifilter Rotating Shadowband Radiometer derived Cloud Optical depth, to get cloud effective radius (Reff, we observe under certain specialized conditions, clear signatures of the Twomey Aerosol Indirect effect on cloud droplet properties which are consistent with the theoretical bounds. We also show that the measurement is very sensitive to how far the aerosol layer is from the cloud base and demonstrate that surface PM25 is far less useful. Measurements from both the DOE ARM site and new results at CCNY are presented.

  11. The aerosol distribution in Europe derived with the Community Multiscale Air Quality (CMAQ model: comparison to near surface in situ and sunphotometer measurements

    Directory of Open Access Journals (Sweden)

    V. Matthias

    2008-09-01

    Full Text Available The aerosol distribution in Europe was simulated with the Community Multiscale Air Quality (CMAQ model system version 4.5 for the years 2000 and 2001. The results were compared with daily averages of PM10 measurements taken in the framework of EMEP and with aerosol optical depth (AOD values measured within AERONET. The modelled total aerosol mass is typically about 30–60% lower than the corresponding measurements. However a comparison of the chemical composition of the aerosol revealed a considerably better agreement between the modelled and the measured aerosol components for ammonium, nitrate and sulfate, which are on average only 15–20% underestimated. Sligthly worse agreement was determined for sea salt, that was only avaliable at two sites. The largest discrepancies result from the aerosol mass which was not chemically specified by the measurements. The agreement between measurements and model is better in winter than in summer. The modelled organic aerosol mass is higher in summer than in winter but it is significantly underestimated by the model. This could be one of the main reasons for the discrepancies between measurements and model results. The other is that primary coarse particles are underestimated in the emissions. The probability distribution function of the PM10 measurements follows a log-normal distribution at most sites. The model is only able to reproduce this distribution function at non-coastal low altitude stations. The AOD derived from the model results is 20–70% lower than the values observed within AERONET. This is mainly attributed to the missing aerosol mass in the model. The day-to-day variability of the AOD and the log-normal distribution functions are quite well reproduced by the model. The seasonality on the other hand is underestimated by the model results because better agreement is achieved in winter.

  12. Intercomparison test of various aerosol measurement techniques

    International Nuclear Information System (INIS)

    Cherdron, W.; Hassa, C.; Jordan, S.

    1984-01-01

    At the suggestion of the CONT group (Containment Loading and Response), which is a subgroup of the Safety Working Group of the Fast Reactor Coordinating Committee, a group of experts undertook a comparison of the techniques of sodium aerosol measurement used in various laboratories in the EC. The following laboratories took part in the exercise: CEN-Mol (Belgium), CEA-Cadarache (France), CEA-Fontenay-aux-Roses (France), KfK-Karlsruhe (Federal Republic of Germany), ENEA-Bologna (Italy), and UKAEA-Winfrith (United Kingdom). The objective of the aerosol measurement workshop was to assess the applicability and reliability of specific aerosol measuring instruments. Measurements performed with equipment from the participating laboratories were evaluated using a standard procedure. This enabled an estimate of the accuracy of the experimental data to be provided for the verification of aerosol codes. Thus these results can be used as input for the physical modelling of aerosol behaviour, and the work reported here is a contribution to the definition of the radioactive source term for severe accidents in LMFBRs. The aerosol experts participating in the exercise agreed to concentrate on the techniques of measuring aerosol particle size distributions. The tests were performed at the FAUNA test facility using the aerosol loop. A sodium spray fire, which provides a continuous aerosol source of variable concentration, was produced under open-loop conditions in this facility. Although the primary objective of the workshop was to determine the particle size distributions of the aerosols, measurements of the sodium mass concentration were also made

  13. Measurements of Aerosol Characteristics in Skocjan Caves

    International Nuclear Information System (INIS)

    Jovanovic, P.

    2013-01-01

    Measurements of radon concentration and radon progeny concentration (attached and unattached) have been performed in Skocjan caves. In the same time also aerosol concentration (PM 10 ), aerosol size distribution with ten stage Hauke impactor and Scanning Mobility Particle Sizer - SMPS have been performed. The idea was to find impact of outer air and visitors to the aerosol characteristics of cave air. Measurements with impactor have been implemented in summer and winter period, with SMPS only in summer period. Radon concentrations ranged in winter period in region from 500 to 1000 Bq/m 3 , equilibrium factor was about 55 %. In summer period radon concentration increased up to 10 kBq/m 3 , equilibrium factor was about 45 %, and unattached fraction went up to 20 %. Measurements of aerosol size distribution show lower aerosol sizes in winter season (around 1 μm) and bigger aerosol sizes in summer season (around 3 - 6 μm). We could not find good correlation between unattached fraction and aerosol size distribution. Also we could not find clear impact of visitors to the air characteristics in cave. Probably our measuring location was too close to the entrance and the impact of outer air was too high. We will repeat measurements deeper in cave to find better results.(author)

  14. Aerosol behaviour modeling and measurements

    Energy Technology Data Exchange (ETDEWEB)

    Gieseke, J A; Reed, L D [Batelle Memorial Institute, Columbus, OH (United States)

    1977-01-01

    Aerosol behavior within Liquid Metal Fast Breeder Reactor (LMFBR) containments is of critical importance since most of the radioactive species are expected to be associated with particulate forms and the mass of radiologically significant material leaked to the ambient atmosphere is directly related to the aerosol concentration airborne within the containment. Mathematical models describing the behavior of aerosols in closed environments, besides providing a direct means of assessing the importance of specific assumptions regarding accident sequences, will also serve as the basic tool with which to predict the consequences of various postulated accident situations. Consequently, considerable efforts have been recently directed toward the development of accurate and physically realistic theoretical aerosol behavior models. These models have accounted for various mechanisms affecting agglomeration rates of airborne particulate matter as well as particle removal rates from closed systems. In all cases, spatial variations within containments have been neglected and a well-mixed control volume has been assumed. Examples of existing computer codes formulated from the mathematical aerosol behavior models are the Brookhaven National Laboratory TRAP code, the PARDISEKO-II and PARDISEKO-III codes developed at Karlsruhe Nuclear Research Center, and the HAA-2, HAA-3, and HAA-3B codes developed by Atomics International. Because of their attractive short computation times, the HAA-3 and HAA-3B codes have been used extensively for safety analyses and are attractive candidates with which to demonstrate order of magnitude estimates of the effects of various physical assumptions. Therefore, the HAA-3B code was used as the nucleus upon which changes have been made to account for various physical mechanisms which are expected to be present in postulated accident situations and the latest of the resulting codes has been termed the HAARM-2 code. It is the primary purpose of the HAARM

  15. Correlative measurements of the stratospheric aerosols

    Science.gov (United States)

    Santer, R.; Brogniez, C.; Herman, M.; Diallo, S.; Ackerman, M.

    1992-12-01

    Joint experiments were organized or available during stratospheric flights of a photopolarimeter, referred to as RADIBAL (radiometer balloon). In May 1984, RADIBAL flew simultaneously with another balloonborne experiment conducted by the Institut d'Aeronomie Spatiale de Belgique (IASB), which provides multiwavelength vertical profiles of the aerosol scattering coefficient. At this time, the El Chichon layer was observable quite directly from mountain sites. A ground-based station set up at Pic du Midi allowed an extensive description of the aerosol optical properties. The IASB and the Pic du Midi observations are consistent with the aerosol properties derived from the RADIBAL measurement analysis.

  16. An algorithm for hyperspectral remote sensing of aerosols: 2. Information content analysis for aerosol parameters and principal components of surface spectra

    Science.gov (United States)

    Hou, Weizhen; Wang, Jun; Xu, Xiaoguang; Reid, Jeffrey S.

    2017-05-01

    This paper describes the second part of a series of investigation to develop algorithms for simultaneous retrieval of aerosol parameters and surface reflectance from the future hyperspectral and geostationary satellite sensors such as Tropospheric Emissions: Monitoring of POllution (TEMPO). The information content in these hyperspectral measurements is analyzed for 6 principal components (PCs) of surface spectra and a total of 14 aerosol parameters that describe the columnar aerosol volume Vtotal, fine-mode aerosol volume fraction, and the size distribution and wavelength-dependent index of refraction in both coarse and fine mode aerosols. Forward simulations of atmospheric radiative transfer are conducted for 5 surface types (green vegetation, bare soil, rangeland, concrete and mixed surface case) and a wide range of aerosol mixtures. It is shown that the PCs of surface spectra in the atmospheric window channel could be derived from the top-of-the-atmosphere reflectance in the conditions of low aerosol optical depth (AOD ≤ 0.2 at 550 nm), with a relative error of 1%. With degree freedom for signal analysis and the sequential forward selection method, the common bands for different aerosol mixture types and surface types can be selected for aerosol retrieval. The first 20% of our selected bands accounts for more than 90% of information content for aerosols, and only 4 PCs are needed to reconstruct surface reflectance. However, the information content in these common bands from each TEMPO individual observation is insufficient for the simultaneous retrieval of surface's PC weight coefficients and multiple aerosol parameters (other than Vtotal). In contrast, with multiple observations for the same location from TEMPO in multiple consecutive days, 1-3 additional aerosol parameters could be retrieved. Consequently, a self-adjustable aerosol retrieval algorithm to account for surface types, AOD conditions, and multiple-consecutive observations is recommended to derive

  17. Satellite measurements of aerosol mass and transport

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, R.S.; Kaufman, Y.J.; Mahoney, R.L.

    1984-01-01

    The aerosol optical thickness over land is derived from satellite measurements of the radiance of scattered sunlight. These data are used to estimate the columnar mass density of particulate sulfur on a day with a large amount of sulfur. The horizontal transport of the particulate sulfur is calculated using wing vectors measured with rawins. 33 references, 7 figures, 1 table.

  18. A transuranic aerosol measurement system: Preliminary results

    International Nuclear Information System (INIS)

    Prevo, C.T.; Kaifer, R.C.; Rueppel, D.W.; Delvasto, R.M.; Biermann, A.H.; Phelps, P.L.

    1986-10-01

    We have completed the design, fabrication, and assembly of a computer-based prototype system for the measurement of transuranic aerosols in the workplace and environment. This system (called WOTAMS for Workplace Transuranic Aerosol Measurement System) incorporates two detectors: (1) an in-line solid-state alpha detector that sends out an alarm the moment a transuranic release occurs, and (2) an in-vacuum detector that increases off-line-analysis sensitivity. The in-line sensitivity of the system is better than 5.0 MPC-h, and the in-vacuum sensitivity exceeds 0.5 MPC-h. 5 refs., 8 figs., 1 tab

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

    Science.gov (United States)

    Kreuter, A; Emde, C; Blumthaler, M

    2010-11-01

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

  20. Novel Measurements of Aerosol Particle Interfaces Using Biphasic Microfluidics

    Science.gov (United States)

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

    2014-12-01

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

  1. A case study of the impact of boundary layer aerosol size distribution on the surface UV irradiance

    Energy Technology Data Exchange (ETDEWEB)

    Kikas, U.; Reinhart, A. [University of Tartu (Estonia). Institute of Environmental Physics; Vaht, M. [Parnu Institute of Health Resort Treatment and Medical Rehabilitation (Estonia); Veismann, U. [Tartu Observatory (Estonia)

    2001-07-01

    The relationship between scattering characteristics of surface aerosol and surface UV irradiance was examined on the basis of the measurements carried out in June-August 1999 in Parnu, Estonia on the Eastern coast of the Baltic Sea (58{sup o}22'27 ''N, 24{sup o}30'43 ''E) The UV radiation spectra (300-34Onm) were measured with the Ocean Optics Inc. UV spectrometer PC 1000, the aerosol size distributions (3-1000nm) were measured with the electric aerosol spectrometer EAS. A case study was conducted for six sequential cloudless days, when the decrease of the surface UV irradiance was seemingly influenced by atmospheric aerosol. Aerosol radiative properties were calculated from the measured size distributions that represented the maritime polar (North Atlantic) and mixed maritime-continental air. The aerosol optical depths at 500nm for the North Atlantic air were estimated to be from 0.08 to 0. 13. The spectral aerosol optical depth agreed well with the Angstrom law, the Angstrom exponent ({alpha} varied from day to day between values of 0.52-0.90. Aerosol asymmetry factor at 300nm changed between values of 0.76 and 0.80, and was highly correlated with the mean radius of aerosol number distribution. The total aerosol UV scattering was mostly influenced by changes in aerosol with a diameter of 100-560nm. The aerosol scattering coefficients were positively correlated with the relative humidity of air. The ground aerosol properties were used for calculating the surface UV irradiance from the radiative transfer model of Bird and Riordan (J. Climate Appl. Meteorol. 25 (1986)). The calculated UV irradiances correlated quite well with the measured ones, showing that the use of ground aerosol data for radiative transfer calculations turned out reasonable results. However, ignoring the changes in the aerosol vertical distribution resulted in overestimation of aerosol optical depth on hazy days. (author)

  2. Putative cryomagma interaction with aerosols deposit at Titan's surface

    Science.gov (United States)

    Coll, Patrice; Navarro-Gonzalez, Rafael; Raulin, Francois; Coscia, David; Ramirez, Sandra I.; Buch, Arnaud; Szopa, Cyril; Poch, Olivier; Cabane, Michel; Brassé, Coralie

    The largest moon of Saturn, Titan, is known for its dense, nitrogen-rich atmosphere. The organic aerosols which are produced in Titan’s atmosphere are of great astrobiological interest, particularly because of their potential evolution when they reach the surface and may interact with putative ammonia-water cryomagma [1]. In this context we have followed the evolution of alkaline pH hydrolysis (25wt% ammonia-water) of Titan aerosol analogues, that have been qualified as representative of Titan’s aerosols [2]. Indeed the first results obtained by the ACP experiment onboard Huygens probe revealed that the main products obtained after thermolysis of Titan’s collected aerosols, were ammonia (NH3) and hydrogen cyanide (HCN). Then performing a direct comparison of the volatiles produced after a thermal treatment done in conditions similar to the ones used by the ACP experiment, we may estimate that the tholins we used are relevant to chemical analogues of Titan’s aerosols, and to note free of oxygen. Taking into account recent studies proposing that the subsurface ocean may contain a lower fraction of ammonia (about 5wt% or less [3]), and assuming the presence of specific gas species [4, 5], in particular CO2 and H2S, trapped in likely internal ocean, we determine a new probable composition of the cryomagma which could potentially interact with deposited Titan’s aerosols. We then carried out different hydrolyses, taking into account this composition, and we established the influence of the hydrolysis temperature on the organic molecules production. References: [1] Mitri et al., 2008. Resurfacing of Titan by ammonia-water cryomagma. Icarus. 196, 216-224. [2] Coll et al. 2013, Can laboratory tholins mimic the chemistry producing Titan's aerosols? A review in light of ACP experimental results, Planetary and Space Science 77, 91-103. [3] Tobie et al. 2012. Titan’s Bulk Composition Constrained by Cassini-Huygens: implication for internal outgassing. The

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

    Science.gov (United States)

    Atwood, Samuel A.; Reid, Jeffrey S.; Kreidenweis, Sonia M.; Cliff, Stephen S.; Zhao, Yongjing; Lin, Neng-Huei; Tsay, Si-Chee; Chu, Yu-Chi; Westphal, Douglas L.

    2012-01-01

    Large sources of aerosol particles and their precursors are ubiquitous in East Asia. Such sources are known to impact the South China Sea (henceforth SCS), a sometimes heavily polluted region that has been suggested as particularly vulnerable to climate change. To help elucidate springtime aerosol transport into the SCS, an intensive study was performed on the remote Dongsha (aka Pratas) Islands Atoll in spring 2010. As part of this deployment, a Davis Rotating-drum Uniform size-cut Monitor (DRUM) cascade impactor was deployed to collect size-resolved aerosol samples at the surface that were analyzed by X-ray fluorescence for concentrations of selected elements. HYSPLIT backtrajectories indicated that the transport of aerosol observed at the surface at Dongsha was occurring primarily from regions generally to the north and east. This observation was consistent with the apparent persistence of pollution and dust aerosol, along with sea salt, in the ground-based dataset. In contrast to the sea-level observations, modeled aerosol transport suggested that the westerly flow aloft (w700 hPa) transported smoke-laden air toward the site from regions from the south and west. Measured aerosol optical depth at the site was highest during time periods of modeled heavy smoke loadings aloft. These periods did not coincide with elevated aerosol concentrations at the surface, although the model suggested sporadic mixing of this free-tropospheric aerosol to the surface over the SCS. A biomass burning signature was not clearly identified in the surface aerosol composition data, consistent with this aerosol type remaining primarily aloft and not mixing strongly to the surface during the study. Significant vertical wind shear in the region also supports the idea that different source regions lead to varying aerosol impacts in different vertical layers, and suggests the potential for considerable vertical inhomogeneity in the SCS aerosol environment.

  4. Aerosol measurements and nuclear accidents: a reconsideration

    International Nuclear Information System (INIS)

    Raes, F.

    1988-01-01

    Within its radioactivity environmental monitoring programme, the Commission of the European Communities and in particular its Joint Research Centre wants to encourage the qualitative improvement of radioactivity monitoring. On 3 and 4 December 1987 an experts' meeting has been organized by the Ispra Joint Research Centre in collaboration with the Gesellschaft fuer Aerosolforschung, in order to discuss measuring techniques for radioactive aerosols in the environment in case of a nuclear accident. During the workshop, current practices in routine monitoring programmes in the near and far field of nuclear power plants were confronted with the latest developments in the metrology of aerosols and radioactivity. The need and feasibility of implementing advanced aerosol and radioactivity techniques in routine monitoring networks have been discussed. This publication gives the full text of 12 presentations and a report of the roundtable discussion being held afterwards. It does not intend to give a complete picture of all activities going on in the field of radioactive aerosol metrology; it rather collects a number of common statements of people who approach the problem from quite different directions

  5. Estimation of Uncertainty in Aerosol Concentration Measured by Aerosol Sampling System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Chan; Song, Yong Jae; Jung, Woo Young; Lee, Hyun Chul; Kim, Gyu Tae; Lee, Doo Yong [FNC Technology Co., Yongin (Korea, Republic of)

    2016-10-15

    FNC Technology Co., Ltd has been developed test facilities for the aerosol generation, mixing, sampling and measurement under high pressure and high temperature conditions. The aerosol generation system is connected to the aerosol mixing system which injects SiO{sub 2}/ethanol mixture. In the sampling system, glass fiber membrane filter has been used to measure average mass concentration. Based on the experimental results using main carrier gas of steam and air mixture, the uncertainty estimation of the sampled aerosol concentration was performed by applying Gaussian error propagation law. FNC Technology Co., Ltd. has been developed the experimental facilities for the aerosol measurement under high pressure and high temperature. The purpose of the tests is to develop commercial test module for aerosol generation, mixing and sampling system applicable to environmental industry and safety related system in nuclear power plant. For the uncertainty calculation of aerosol concentration, the value of the sampled aerosol concentration is not measured directly, but must be calculated from other quantities. The uncertainty of the sampled aerosol concentration is a function of flow rates of air and steam, sampled mass, sampling time, condensed steam mass and its absolute errors. These variables propagate to the combination of variables in the function. Using operating parameters and its single errors from the aerosol test cases performed at FNC, the uncertainty of aerosol concentration evaluated by Gaussian error propagation law is less than 1%. The results of uncertainty estimation in the aerosol sampling system will be utilized for the system performance data.

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

    Science.gov (United States)

    Petrenko, M.; Ichoku, C.

    2013-01-01

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

  7. Overview and preliminary results of the Surface Ocean Aerosol Production (SOAP campaign

    Directory of Open Access Journals (Sweden)

    C. S. Law

    2017-11-01

    Full Text Available Establishing the relationship between marine boundary layer (MBL aerosols and surface water biogeochemistry is required to understand aerosol and cloud production processes over the remote ocean and represent them more accurately in earth system models and global climate projections. This was addressed by the SOAP (Surface Ocean Aerosol Production campaign, which examined air–sea interaction over biologically productive frontal waters east of New Zealand. This overview details the objectives, regional context, sampling strategy and provisional findings of a pilot study, PreSOAP, in austral summer 2011 and the following SOAP voyage in late austral summer 2012. Both voyages characterized surface water and MBL composition in three phytoplankton blooms of differing species composition and biogeochemistry, with significant regional correlation observed between chlorophyll a and DMSsw. Surface seawater dimethylsulfide (DMSsw and associated air–sea DMS flux showed spatial variation during the SOAP voyage, with maxima of 25 nmol L−1 and 100 µmol m−2 d−1, respectively, recorded in a dinoflagellate bloom. Inclusion of SOAP data in a regional DMSsw compilation indicates that the current climatological mean is an underestimate for this region of the southwest Pacific. Estimation of the DMS gas transfer velocity (kDMS by independent techniques of eddy covariance and gradient flux showed good agreement, although both exhibited periodic deviations from model estimates. Flux anomalies were related to surface warming and sea surface microlayer enrichment and also reflected the heterogeneous distribution of DMSsw and the associated flux footprint. Other aerosol precursors measured included the halides and various volatile organic carbon compounds, with first measurements of the short-lived gases glyoxal and methylglyoxal in pristine Southern Ocean marine air indicating an unidentified local source. The application of a real-time clean sector

  8. Applications of Sunphotometry to Aerosol Extinction and Surface Anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Tsay, S.

    2002-09-30

    Support cost-sharing of a newly developed sunphotometer in field deployment for aerosol studies. This is a cost-sharing research to deploy a newly developed sun-sky-surface photometer for studying aerosol extinction and surface anisotropy at the ARM SGP, TWP, and NSA-AAO CART sites and in many field campaigns. Atmospheric aerosols affect the radiative energy balance of the Earth, both directly by perturbing the incoming/outgoing radiation fields and indirectly by influencing the properties/processes of clouds and reactive greenhouse gases. The surface bidirectional reflectance distribution function (BRDF) also plays a crucial role in the radiative energy balance, since the BRDF is required to determine (i) the spectral and spectrally-averaged surface albedo, and (ii) the top-of-the-atmosphere (TOA) angular distribution of radiance field. Therefore, the CART sites provide an excellent, albeit unique, opportunity to collect long-term climatic data in characterizing aerosol properties and various types of surface anisotropy.

  9. Miniature Sensor for Aerosol Mass Measurements, Phase I

    Data.gov (United States)

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

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

    Science.gov (United States)

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

    2004-01-01

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

  11. Street canyon aerosol pollutant transport measurements.

    Science.gov (United States)

    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.

  12. Determination of atmospheric aerosol properties over land using satellite measurements

    NARCIS (Netherlands)

    Kokhanovsky, A.A.; Leeuw, G. de

    2009-01-01

    Mostly, aerosol properties are poorly understood because the aerosol properties are very sparse. The first workshop on the determination of atmospheric aerosol properties over land using satellite measurements is convened in Bremen, Germany. In this workshop, the topics of discussions included a

  13. Influence of Aerosols And Surface Reflectance On NO2 Retrieval Over China From 2005 to 2015

    Science.gov (United States)

    Liu, M.; Lin, J.

    2016-12-01

    Satellite observation is a powerful way to analysis annual and seasonal variations of nitrogen dioxide (NO2). However, much retrieval of vertical column densities (VCDs) of normally do not explicitly account for aerosol optical effects and surface reflectance anisotropy that vary with space and time. In traditional retrieval, aerosols' effects are often considered as cloud. However, China has complicated aerosols type and aerosol loading. Their optical properties may be very different from the cloud. Furthermore, China has undergone big changes in land use type in recent 10 years. Traditional climatology surface reflectance data may not have representation. In order to study spatial-temporal variation of and influences of these two factors on variations and trends, we use an improved retrieval method of VCDs over China, called the POMINO, based on measurements from the Ozone Monitoring Instrument (OMI), and we compare the results of without aerosol, without surface reflectance treatments and without both to the original POMINO product from 2005 to 2015. Furthermore, we will study correspondent spatial-temporal variations of aerosols, represented by MODIS aerosol optical depth (AOD) data and CALIOP extinction data; surface reflectance, represented by MODIS bidirectional reflectance distribution function (BRDF) data.

  14. Biomass burning aerosols characterization from ground based and profiling measurements

    Science.gov (United States)

    Marin, Cristina; Vasilescu, Jeni; Marmureanu, Luminita; Ene, Dragos; Preda, Liliana; Mihailescu, Mona

    2018-04-01

    The study goal is to assess the chemical and optical properties of aerosols present in the lofted layers and at the ground. The biomass burning aerosols were evaluated in low level layers from multi-wavelength lidar measurements, while chemical composition at ground was assessed using an Aerosol Chemical Speciation Monitor (ACSM) and an Aethalometer. Classification of aerosol type and specific organic markers were used to explore the potential to sense the particles from the same origin at ground base and on profiles.

  15. Adsorption and revaporisation studies on iodine oxide aerosols deposited on containment surface materials in LWR

    Energy Technology Data Exchange (ETDEWEB)

    Tietze, S.; Foreman, M.R.StJ.; Ekberg, C. [Chalmers Univ. of Technology, Goeteborg (Sweden); Kaerkelae, T.; Auvinen, A.; Tapper, U.; Lamminmaeki, S.; Jokiniemi, J. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2012-12-15

    During a hypothetical severe nuclear accident, the radiation field will be very high in the nuclear reactor containment building. As a result gaseous radiolysis products will be formed. Elemental iodine can react in the gaseous phase with ozone to form solid iodine oxide aerosol particles (iodine oxide). Within the AIAS (Adsorption of Iodine oxide Aerosols on Surfaces) project the interactions of iodine oxide (IOx) aerosols with common containment surface materials were investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS, as well as Pt and Pd surfaces from hydrogen recombiners. Non-radioactive and {sup 131}I labelled iodine oxide aerosols were produced with the EXSI CONT facility from elemental iodine and ozone at VTT Technical Research Centre of Finland. The iodine oxide deposits were analysed with microscopic and spectroscopic measurement techniques to identify the kind of iodine oxide formed and if a chemical conversion on the different surface materials occurs. The revaporisation behaviour of the deposited iodine oxide aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 having a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The revaporisated {sup 131}I species from the surfaces were chemically tested for elemental iodine formation. The parameter dominating the degradation of the produced iodine oxide aerosols was humidity. Cu and Zn surfaces were found to react with iodine from the iodine oxide aerosols to form iodides, while no metal iodides were detected for Al and SS samples. Most of the iodine oxide aerosols are assumed to

  16. Adsorption and revaporisation studies on iodine oxide aerosols deposited on containment surface materials in LWR

    International Nuclear Information System (INIS)

    Tietze, S.; Foreman, M.R.StJ.; Ekberg, C.; Kaerkelae, T.; Auvinen, A.; Tapper, U.; Lamminmaeki, S.; Jokiniemi, J.

    2012-12-01

    During a hypothetical severe nuclear accident, the radiation field will be very high in the nuclear reactor containment building. As a result gaseous radiolysis products will be formed. Elemental iodine can react in the gaseous phase with ozone to form solid iodine oxide aerosol particles (iodine oxide). Within the AIAS (Adsorption of Iodine oxide Aerosols on Surfaces) project the interactions of iodine oxide (IOx) aerosols with common containment surface materials were investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS, as well as Pt and Pd surfaces from hydrogen recombiners. Non-radioactive and 131 I labelled iodine oxide aerosols were produced with the EXSI CONT facility from elemental iodine and ozone at VTT Technical Research Centre of Finland. The iodine oxide deposits were analysed with microscopic and spectroscopic measurement techniques to identify the kind of iodine oxide formed and if a chemical conversion on the different surface materials occurs. The revaporisation behaviour of the deposited iodine oxide aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 having a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The revaporisated 131 I species from the surfaces were chemically tested for elemental iodine formation. The parameter dominating the degradation of the produced iodine oxide aerosols was humidity. Cu and Zn surfaces were found to react with iodine from the iodine oxide aerosols to form iodides, while no metal iodides were detected for Al and SS samples. Most of the iodine oxide aerosols are assumed to be

  17. Development and first application of an Aerosol Collection Module (ACM) for quasi online compound specific aerosol measurements

    Science.gov (United States)

    Hohaus, Thorsten; Kiendler-Scharr, Astrid; Trimborn, Dagmar; Jayne, John; Wahner, Andreas; Worsnop, Doug

    2010-05-01

    Atmospheric aerosols influence climate and human health on regional and global scales (IPCC, 2007). In many environments organics are a major fraction of the aerosol influencing its properties. Due to the huge variety of organic compounds present in atmospheric aerosol current measurement techniques are far from providing a full speciation of organic aerosol (Hallquist et al., 2009). The development of new techniques for compound specific measurements with high time resolution is a timely issue in organic aerosol research. Here we present first laboratory characterisations of an aerosol collection module (ACM) which was developed to allow for the sampling and transfer of atmospheric PM1 aerosol. The system consists of an aerodynamic lens system focussing particles on a beam. This beam is directed to a 3.4 mm in diameter surface which is cooled to -30 °C with liquid nitrogen. After collection the aerosol sample can be evaporated from the surface by heating it to up to 270 °C. The sample is transferred through a 60cm long line with a carrier gas. In order to test the ACM for linearity and sensitivity we combined it with a GC-MS system. The tests were performed with octadecane aerosol. The octadecane mass as measured with the ACM-GC-MS was compared versus the mass as calculated from SMPS derived total volume. The data correlate well (R2 0.99, slope of linear fit 1.1) indicating 100 % collection efficiency. From 150 °C to 270 °C no effect of desorption temperature on transfer efficiency could be observed. The ACM-GC-MS system was proven to be linear over the mass range 2-100 ng and has a detection limit of ~ 2 ng. First experiments applying the ACM-GC-MS system were conducted at the Jülich Aerosol Chamber. Secondary organic aerosol (SOA) was formed from ozonolysis of 600 ppbv of b-pinene. The major oxidation product nopinone was detected in the aerosol and could be shown to decrease from 2 % of the total aerosol to 0.5 % of the aerosol over the 48 hours of

  18. Understanding the aerosol information content in multi-spectral reflectance measurements using a synergetic retrieval algorithm

    Directory of Open Access Journals (Sweden)

    D. Martynenko

    2010-11-01

    Full Text Available An information content analysis for multi-wavelength SYNergetic AErosol Retrieval algorithm SYNAER was performed to quantify the number of independent pieces of information that can be retrieved. In particular, the capability of SYNAER to discern various aerosol types is assessed. This information content depends on the aerosol optical depth, the surface albedo spectrum and the observation geometry. The theoretical analysis is performed for a large number of scenarios with various geometries and surface albedo spectra for ocean, soil and vegetation. When the surface albedo spectrum and its accuracy is known under cloud-free conditions, reflectance measurements used in SYNAER is able to provide for 2–4° of freedom that can be attributed to retrieval parameters: aerosol optical depth, aerosol type and surface albedo.

    The focus of this work is placed on an information content analysis with emphasis to the aerosol type classification. This analysis is applied to synthetic reflectance measurements for 40 predefined aerosol mixtures of different basic components, given by sea salt, mineral dust, biomass burning and diesel aerosols, water soluble and water insoluble aerosols. The range of aerosol parameters considered through the 40 mixtures covers the natural variability of tropospheric aerosols. After the information content analysis performed in Holzer-Popp et al. (2008 there was a necessity to compare derived degrees of freedom with retrieved aerosol optical depth for different aerosol types, which is the main focus of this paper.

    The principle component analysis was used to determine the correspondence between degrees of freedom for signal in the retrieval and derived aerosol types. The main results of the analysis indicate correspondence between the major groups of the aerosol types, which are: water soluble aerosol, soot, mineral dust and sea salt and degrees of freedom in the algorithm and show the ability of the SYNAER to

  19. Simulation study of the aerosol information content in OMI spectral reflectance measurements

    Directory of Open Access Journals (Sweden)

    B. Veihelmann

    2007-06-01

    Full Text Available The Ozone Monitoring Instrument (OMI is an imaging UV-VIS solar backscatter spectrometer and is designed and used primarily to retrieve trace gases like O3 and NO2 from the measured Earth reflectance spectrum in the UV-visible (270–500 nm. However, also aerosols are an important science target of OMI. The multi-wavelength algorithm is used to retrieve aerosol parameters from OMI spectral reflectance measurements in up to 20 wavelength bands. A Principal Component Analysis (PCA is performed to quantify the information content of OMI reflectance measurements on aerosols and to assess the capability of the multi-wavelength algorithm to discern various aerosol types. This analysis is applied to synthetic reflectance measurements for desert dust, biomass burning aerosols, and weakly absorbing anthropogenic aerosol with a variety of aerosol optical thicknesses, aerosol layer altitudes, refractive indices and size distributions. The range of aerosol parameters considered covers the natural variability of tropospheric aerosols. This theoretical analysis is performed for a large number of scenarios with various geometries and surface albedo spectra for ocean, soil and vegetation. When the surface albedo spectrum is accurately known and clouds are absent, OMI reflectance measurements have 2 to 4 degrees of freedom that can be attributed to aerosol parameters. This information content depends on the observation geometry and the surface albedo spectrum. An additional wavelength band is evaluated, that comprises the O2-O2 absorption band at a wavelength of 477 nm. It is found that this wavelength band adds significantly more information than any other individual band.

  20. Phenomenological study of aerosol dry deposition in urban area: surface properties, turbulence and local meteorology influences

    International Nuclear Information System (INIS)

    Roupsard, P.

    2013-01-01

    Aerosol dry deposition is not much known for urban areas due to the lack of data. Knowledge on this phenomenon is necessary to understand pollutant fluxes in cities and to estimate inhabitant exposition to ionizing radiation of radioactive aerosols. A data providing could enable to enhance dry deposition models for these areas. An original experimental approach is performed to study submicron aerosol dry deposition on urban surfaces. Wind tunnel coupled to in situ experiments give results to study different physical phenomenon governing dry deposition. Dry deposition velocities are measured using aerosol tracers. These data are associated to turbulent and meteorological measured conditions. This database permits to classify the principal physical phenomenon for each experiment type. Finally, different phenomenon must be considered for chronic and acute exposition of urban surfaces to atmospheric particles. (author)

  1. Filter-based Aerosol Measurement Experiments using Spherical Aerosol Particles under High Temperature and High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Chan; Jung, Woo Young; Lee, Hyun Chul; Lee, Doo Young [FNC TECH., Yongin (Korea, Republic of)

    2016-05-15

    Optical Particle Counter (OPC) is used to provide real-time measurement of aerosol concentration and size distribution. Glass fiber membrane filter also be used to measure average mass concentration. Three tests (MTA-1, 2 and 3) have been conducted to study thermal-hydraulic effect, a filtering tendency at given SiO{sub 2} particles. Based on the experimental results, the experiment will be carried out further with a main carrier gas of steam and different aerosol size. The test results will provide representative behavior of the aerosols under various conditions. The aim of the tests, MTA 1, 2 and 3, are to be able to 1) establish the test manuals for aerosol generation, mixing, sampling and measurement system, which defines aerosol preparation, calibration, operating and evaluation method under high pressure and high temperature 2) develop commercial aerosol test modules applicable to the thermal power plant, environmental industry, automobile exhaust gas, chemical plant, HVAC system including nuclear power plant. Based on the test results, sampled aerosol particles in the filter indicate that important parameters affecting aerosol behavior aerosols are 1) system temperature to keep above a evaporation temperature of ethanol and 2) aerosol losses due to the settling by ethanol liquid droplet.

  2. Synthesis and Surface-Specific Analysis of Molecular Constituents Relevant to Biogenic Secondary Organic Aerosol Material

    Science.gov (United States)

    Be, A. G.; Upshur, M. A.; Chase, H. M.; Geiger, F.; Thomson, R. J.

    2017-12-01

    Secondary organic aerosol (SOA) particles formed from the oxidation of biogenic volatile organic compounds (BVOCs) remain a principal, yet elusive, class of airborne particulate matter that impacts the Earth's radiation budget. Given the characteristic molecular complexity comprising biogenic SOA particles, chemical information selective to the gas-aerosol interface may be valuable in the investigation of such systems, as surface considerations likely dictate the phenomena driving particle evolution mechanisms and climate effects. In particular, cloud activation processes may be parameterized using the surface tension depression that coincides with partitioning of surface-active organic species to the gas-droplet interface. However, the extent to which surface chemical processes, such as cloud droplet condensation, are influenced by the chemical structure and reactivity of individual surface-active molecules in SOA particles is largely unknown. We seek to study terpene-derived organic species relevant to the surfaces of biogenic SOA particles via synthesis of putative oxidation products followed by analysis using surface-selective physicochemical measurements. Using dynamic surface tension measurements, considerable differences are observed in the surface tension depression of aqueous pendant droplets that contain synthetically prepared ozonolysis products derived from abundant terpene precursors. Furthermore, sum frequency generation spectroscopy is utilized for comparison of the surface vibrational spectral responses of synthesized reference compounds with those observed for laboratory aerosol toward probing the surface composition of SOA material. Such ongoing findings highlight the underlying importance of molecular structure and reactivity when considering the surface chemistry of biogenic terpene-derived atmospheric aerosols.

  3. Airborne High Spectral Resolution Lidar Aerosol Measurements during MILAGRO and TEXAQS/GOMACCS

    Science.gov (United States)

    Ferrare, Richard; Hostetler, Chris; Hair, John; Cook Anthony; Harper, David; Burton, Sharon; Clayton, Marian; Clarke, Antony; Russell, Phil; Redemann, Jens

    2007-01-01

    Two1 field experiments conducted during 2006 provided opportunities to investigate the variability of aerosol properties near cities and the impacts of these aerosols on air quality and radiative transfer. The Megacity Initiative: Local and Global Research Observations (MILAGRO) /Megacity Aerosol Experiment in Mexico City (MAX-MEX)/Intercontinental Chemical Transport Experiment-B (INTEX-B) joint experiment conducted during March 2006 investigated the evolution and transport of pollution from Mexico City. The Texas Air Quality Study (TEXAQS)/Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) (http://www.al.noaa.gov/2006/) conducted during August and September 2006 investigated climate and air quality in the Houston/Gulf of Mexico region. During both missions, the new NASA Langley airborne High Spectral Resolution Lidar (HSRL) was deployed on the NASA Langley B200 King Air aircraft and measured profiles of aerosol extinction, backscattering, and depolarization to: 1) characterize the spatial and vertical distributions of aerosols, 2) quantify aerosol extinction and optical thickness contributed by various aerosol types, 3) investigate aerosol variability near clouds, 4) evaluate model simulations of aerosol transport, and 5) assess aerosol optical properties derived from a combination of surface, airborne, and satellite measurements.

  4. Aerosol Measurements with the FRAM Telescope

    Directory of Open Access Journals (Sweden)

    Ebr Jan

    2017-01-01

    Full Text Available Precision stellar photometry using a telescope equipped with a CCD camera is an obvious way to measure the total aerosol content of the atmosphere as the apparent brightness of every star is affected by scattering. Achieving high precision in the vertical aerosol optical depth (at the level of 0.01 presents a series of interesting challenges. Using 3.5 years of data taken by the FRAM instrument at the Pierre Auger Observatory, we have developed a set of methods and tools to overcome most of these challenges. We use a wide-field camera and measure stars over a large span in airmass to eliminate the need for absolute calibration of the instrument. The main issues for data processing include camera calibration, source identification in curved field, catalog deficiencies, automated aperture photometry in rich fields with lens distortion and corrections for star color. In the next step, we model the airmass-dependence of the extinction and subtract the Rayleigh component of scattering, using laboratory measurements of spectral sensitivity of the device. In this contribution, we focus on the caveats and solutions found during the development of the methods, as well as several issues yet to be solved. Finally, future outlooks, such as the possibility for precision measurements of wavelength dependence of the extinction are discussed.

  5. An initial assessment of the impact of Australian aerosols on surface ultraviolet radiation and implications for human health

    International Nuclear Information System (INIS)

    Chee, C Y; Mills, F P

    2010-01-01

    Aerosols can have significant influence on surface radiation, and the intense surface ultraviolet radiation Australia experiences contributes to Australia's high incidence rates for related human diseases. Aerosol properties, such as total column aerosol optical depth, have been measured over several years for varying lengths of time at sites across Australia using sunphotometers. Statistical analysis of the average daily aerosol optical depth over sites near Alice Springs, Canberra, Darwin, and Perth provides one measure of the annual atmospheric loading of aerosols over these sites. The sunphotometers used at these sites do not make measurements in the UV-B spectral region and have only one channel in the UV-A spectral region, the regions of most interest for assessing human health impact. Consequently, model calculations using standard aerosol types have been used to make an initial estimate of the impact of the aerosols found over these four sites on surface ultraviolet radiation. The aerosol loading is at times sufficient to significantly reduce the surface ultraviolet radiation, but few such days occur each year. The annual average effect of aerosols on surface ultraviolet radiation, thus, appears to be small compared to lifestyle factors, such as clothing and use of sunscreen.

  6. Measurements of dynamic shape factors of LMFBR aggregate aerosols

    International Nuclear Information System (INIS)

    Allen, M.D.; Moss, O.R.; Briant, J.K.

    1980-01-01

    Dynamic shape factors for branched, chain-like aggregates of LMFBR mixed-oxide fuels have been measured with a LAPS spiral-duct centrifuge. The aerosol was generated by repeatedly pulsing a focused laser beam onto the surface of a typical LMFBR fuel pellet. The measured values of the dynamic shape factor, corrected for slip, vary between kappa = 3.60 at D/sub ae/ = 0.5 μm, and kappa = 2.23 at D/sub ae/ = 1.5 μm

  7. Direct measurement of aerosol shape factors

    International Nuclear Information System (INIS)

    Zeller, W.

    1983-12-01

    The dynamic shape factor whereas the coagulation shape factor is an average over the total examined size range. The experiments have shown that the results of experiments with a certain aerosol system cannot be transferred to other aerosol systems without further consideration. The outer shape of particles of a certain size depends on the specific properties of the material as well as on the experimental conditions during the aerosol generation. For both aerosol systems examined the mean dynamic shape factor, averaged over the total examined size range, agrees roughly with the coagulation shape factor. (Description of aerosol centrifuge and of differential mobility analyzer). (orig./HP) [de

  8. Development and Testing of the New Surface LER Climatology for OMI UV Aerosol Retrievals

    Science.gov (United States)

    Gupta, Pawan; Torres, Omar; Jethva, Hiren; Ahn, Changwoo

    2014-01-01

    Ozone Monitoring Instrument (OMI) onboard Aura satellite retrieved aerosols properties using UV part of solar spectrum. The OMI near UV aerosol algorithm (OMAERUV) is a global inversion scheme which retrieves aerosol properties both over ocean and land. The current version of the algorithm makes use of TOMS derived Lambertian Equivalent Reflectance (LER) climatology. A new monthly climatology of surface LER at 354 and 388 nm have been developed. This will replace TOMS LER (380 nm and 354nm) climatology in OMI near UV aerosol retrieval algorithm. The main objectives of this study is to produce high resolution (quarter degree) surface LER sets as compared to existing one degree TOMS surface LERs, to product instrument and wavelength consistent surface climatology. Nine years of OMI observations have been used to derive monthly climatology of surface LER. MODIS derived aerosol optical depth (AOD) have been used to make aerosol corrections on OMI wavelengths. MODIS derived BRDF adjusted reflectance product has been also used to capture seasonal changes in the surface characteristics. Finally spatial and temporal averaging techniques have been used to fill the gaps around the globes, especially in the regions with consistent cloud cover such as Amazon. After implementation of new surface data in the research version of algorithm, comparisons of AOD and single scattering albedo (SSA) have been performed over global AERONET sites for year 2007. Preliminary results shows improvements in AOD retrievals globally but more significance improvement were observed over desert and bright locations. We will present methodology of deriving surface data sets and will discuss the observed changes in retrieved aerosol properties with respect to reference AERONET measurements.

  9. SAGE II Measurements of Stratospheric Aerosol Properties at Non-Volcanic Levels

    Science.gov (United States)

    Thomason, Larry W.; Burton, Sharon P.; Luo, Bei-Ping; Peter, Thomas

    2008-01-01

    Since 2000, stratospheric aerosol levels have been relatively stable and at the lowest levels observed in the historical record. Given the challenges of making satellite measurements of aerosol properties at these levels, we have performed a study of the sensitivity of the product to the major components of the processing algorithm used in the production of SAGE II aerosol extinction measurements and the retrieval process that produces the operational surface area density (SAD) product. We find that the aerosol extinction measurements, particularly at 1020 nm, remain robust and reliable at the observed aerosol levels. On the other hand, during background periods, the SAD operational product has an uncertainty of at least a factor of 2 during due to the lack of sensitivity to particles with radii less than 100 nm.

  10. Estimating the maritime component of aerosol optical depth and its dependency on surface wind speed using satellite data

    Directory of Open Access Journals (Sweden)

    Y. Lehahn

    2010-07-01

    Full Text Available Six years (2003–2008 of satellite measurements of aerosol parameters from the Moderate Resolution Imaging Spectroradiometer (MODIS and surface wind speeds from Quick Scatterometer (QuikSCAT, the Advanced Microwave Scanning Radiometer (AMSR-E, and the Special Sensor Microwave Imager (SSM/I, are used to provide a comprehensive perspective on the link between surface wind speed and marine aerosol optical depth over tropical and subtropical oceanic regions. A systematic comparison between the satellite derived fields in these regions allows to: (i separate the relative contribution of wind-induced marine aerosol to the aerosol optical depth; (ii extract an empirical linear equation linking coarse marine aerosol optical depth and wind intensity; and (iii identify a time scale for correlating marine aerosol optical depth and surface wind speed. The contribution of wind induced marine aerosol to aerosol optical depth is found to be dominated by the coarse mode elements. When wind intensity exceeds 4 m/s, coarse marine aerosol optical depth is linearly correlated with the surface wind speed, with a remarkably consistent slope of 0.009±0.002 s/m. A detailed time scale analysis shows that the linear correlation between the fields is well kept within a 12 h time frame, while sharply decreasing when the time lag between measurements is longer. The background aerosol optical depth, associated with aerosols that are not produced in-situ through wind driven processes, can be used for estimating the contributions of terrestrial and biogenic marine aerosol to over-ocean satellite retrievals of aerosol optical depth.

  11. SAGE II measurements of early Pinatubo aerosols

    Science.gov (United States)

    Mccormick, M. P.; Veiga, R. E.

    1992-01-01

    SAGE II satellite measurements of the Mt. Pinatubo eruption cloud in the stratosphere during June, July, and early August 1991 show that aerosols in the tropics reached as high as 29 km altitude with most of the cloud between 20 and 25 km. The most optically thick portions of the cloud covered latitudes from 10 deg S to 30 deg N during the early part of this period. By late July, high stratospheric optical depths were observed to at least 70 deg N, with the high values north of about 30 deg N from layers below 20 km. High pressure systems in both hemispheres were observed to be correlated with the movement of volcanic material at 21 km into the westerly jet stream at high southern latitudes and similarly to high northern latitudes at 16 km. By August, the entire Southern Hemisphere had experienced a 10-fold increase in optical depth relative to early July due to layers above 20 km. Initial mass calculations using SAGE II data place the aerosol produced from this eruption at 20 to 30 megatons, well above the 12 megatons produced by El Chichon.

  12. Micrometeorological flux measurements of aerosol and gases above Beijing

    Science.gov (United States)

    Nemitz, Eiko; Langford, Ben; Mullinger, Neil; Cowan, Nicholas; Coyle, Mhairi; Acton, William Joe; Lee, James; Fu, Pingqing

    2017-04-01

    Air pollution is estimated to cause 1.6 million premature deaths in China every year and in the winter 2016/17 Beijing had to issue health alerts and put in place ad hoc limitations on industrial and vehicular activity. Much of this pollution is attributed to emissions from industrial processes and in particular coal combustion. By contrast, the diffuse pollutant sources within the city are less well understood. This includes, e.g., emissions from the Beijing traffic fleet, the sewage system, food preparation, solid fuel combustion in the streets and small industrial processes. Within the framework of a major UK-Chinese collaboration to study air pollution and its impact on human health in Beijing, we therefore measured fluxes of a large range of pollutants from a height of 102 m on the 325 m meteorological tower at the Institute of Atmospheric Physics. Several instruments were mounted at 102 m: fluxes of CO2 and H2O were measured with an infrared gas analyser (LiCOR 7500) and fluxes of ozone with a combination of a relative fast-response ozone analyser (ROFI) and a 2B absolute O3 instrument. Total particle number fluxes were measured with a condensation particle counter (TSI CPC 3785), and size-segregated fluxes over the size range 0.06 to 20 μm with a combination of an optical Ultrafine High Sensitivity Aerosol Spectrometer (UHSAS) and an Aerodynamic Particle Sizer Spectrometer (TSI APS3321). Ammonia (NH3) fluxes were measured for the first time above the urban environment using an Aerodyne compact quantum cascade laser (QCL). In addition, composition resolved aerosol fluxes were measured with an Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS), operated in a measurement container at the bottom of the tower, which subsampled from a 120 m long copper tube (15 mm OD). The analysis so far suggests that, due to often low wind speeds, fluxes were at times de-coupled from the surface. Fluxes normalised by CO2, a tracer for the amount of fossil fuel consumed, should be

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

    Directory of Open Access Journals (Sweden)

    L. Hildebrandt

    2010-05-01

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

  14. Measurement of the deposition of aerosol particles to skin, hair and clothing

    International Nuclear Information System (INIS)

    Bell, K.F.

    1999-01-01

    In the event of a nuclear accident, there are several routes whereby human populations may receive a radioactive dose from material released to the environment. The dose from radioactive aerosol deposited onto the surfaces of the human body has previously been estimated by assuming that aerosol deposition velocities (defined as the flux of aerosol onto a surface divided by the aerosol concentration above the surface) onto human body surfaces are similar to the values for inanimate surfaces. However, Jones (1990) modelled the effects on health of fallout material deposited on skin and clothing and found that the number of early deaths from skin dose was sensitively dependent on aerosol deposition velocity. He also pointed out that there was a lack of experimentally derived data on aerosol deposition velocities to human body surfaces and that the above mentioned assumption may not be valid. The purpose of the present work is to measure aerosol deposition velocities onto human body surfaces, the resultant data to allow more accurate nuclear accident consequence modelling. Aerosol deposition velocities onto human body surfaces in simulated indoor conditions have been measured by releasing tracer aerosols of three mean particle diameters (2.6, 6.2 and 9.2μm) into a test chamber containing volunteers. The skin, hair and clothing of the volunteers were sampled and analysed for deposited aerosol by Neutron Activation Analysis. Aerosol deposition velocities onto skin in the range 1.3 - 15 x 10 -3 ms -1 were recorded, values which are approximately an order of magnitude higher than the equivalent values onto the floor of the test room. These values suggest that the exposure route of radioactive aerosol particles deposited on the skin may be more significant than hitherto had been assumed. The possible mechanisms leading to this relatively high deposition were investigated experimentally and the results suggested that a combination of factors such as the body's electrostatic

  15. A characterization of Arctic aerosols on the basis of aerosol optical depth and black carbon measurements

    Directory of Open Access Journals (Sweden)

    R. S. Stone

    2014-06-01

    Full Text Available Abstract Aerosols, transported from distant source regions, influence the Arctic surface radiation budget. When deposited on snow and ice, carbonaceous particles can reduce the surface albedo, which accelerates melting, leading to a temperature-albedo feedback that amplifies Arctic warming. Black carbon (BC, in particular, has been implicated as a major warming agent at high latitudes. BC and co-emitted aerosols in the atmosphere, however, attenuate sunlight and radiatively cool the surface. Warming by soot deposition and cooling by atmospheric aerosols are referred to as “darkening” and “dimming” effects, respectively. In this study, climatologies of spectral aerosol optical depth AOD (2001–2011 and Equivalent BC (EBC (1989–2011 from three Arctic observatories and from a number of aircraft campaigns are used to characterize Arctic aerosols. Since the 1980s, concentrations of BC in the Arctic have decreased by more than 50% at ground stations where in situ observations are made. AOD has increased slightly during the past decade, with variations attributed to changing emission inventories and source strengths of natural aerosols, including biomass smoke and volcanic aerosol, further influenced by deposition rates and airflow patterns.

  16. Size distribution measurements and chemical analysis of aerosol components

    Energy Technology Data Exchange (ETDEWEB)

    Pakkanen, T.A.

    1995-12-31

    with atmospheric sea salt particles. The chloride loss was found to decrease with increasing particle size suggesting that surface reaction mechanisms were important. Overall, the results obtained in this work describe the present methods used in all steps of accurate size distribution measurements of aerosol components and demonstrate the usefulness and possibilities of size distribution measurements in various scientific studies. (orig.)

  17. Aerosol concentration measurements and correlations with air mass trajectories at the Pierre Auger Observatory

    Science.gov (United States)

    Micheletti, M. I.; Louedec, K.; Freire, M.; Vitale, P.; Piacentini, R. D.

    2017-06-01

    Aerosols play an important role in radiative transfer processes involved in different fields of study. In particular, their influence is crucial in the attenuation of light at astronomical and astrophysical observatories, and has to be taken into account in light transfer models employed to reconstruct the signals. The Andean Argentinean region is increasingly being considered as a good candidate to host such facilities, as well as the ones for solar-energy resources, and an adequate knowledge of aerosols characteristics there is needed, but it is not always possible due to the vast area involved and the scarce atmospheric data at ground. The aim of this work is to find correlations between aerosol data and particle trajectories that can give an insight into the origin and behaviour of aerosols in this zone and can be employed in situations in which one does not have local aerosol measurements. For this purpose, an aerosol spectrometer and dust monitor (Grimm 1.109) was installed at the Pierre Auger Observatory of ultra-high-energy cosmic rays, to record aerosol concentrations in different size intervals, at surface level. These measurements are analysed and correlated with air mass trajectories obtained from HYSPLIT (NOAA) model calculations. High aerosol concentrations are registered predominantly when air masses have travelled mostly over continental areas, mainly from the NE direction, while low aerosol concentrations are found in correspondence with air masses coming from the Pacific Ocean, from the NW direction. Different size distribution patterns were found for the aerosols depending on their origin: marine or continental. This work shows for the first time the size distribution of aerosols registered at the Pierre Auger Observatory. The correlations found between mass and particle concentrations (total and for different size ranges) and HYSPLIT air mass trajectories, confirm that the latter can be employed as a useful tool to infer the sources, evolution

  18. Retrieval of aerosol profiles combining sunphotometer and ceilometer measurements in GRASP code

    Science.gov (United States)

    Román, R.; Benavent-Oltra, J. A.; Casquero-Vera, J. A.; Lopatin, A.; Cazorla, A.; Lyamani, H.; Denjean, C.; Fuertes, D.; Pérez-Ramírez, D.; Torres, B.; Toledano, C.; Dubovik, O.; Cachorro, V. E.; de Frutos, A. M.; Olmo, F. J.; Alados-Arboledas, L.

    2018-05-01

    In this paper we present an approach for the profiling of aerosol microphysical and optical properties combining ceilometer and sun/sky photometer measurements in the GRASP code (General Retrieval of Aerosol and Surface Properties). For this objective, GRASP is used with sun/sky photometer measurements of aerosol optical depth (AOD) and sky radiances, both at four wavelengths and obtained from AErosol RObotic NETwork (AERONET), and ceilometer measurements of range corrected signal (RCS) at 1064 nm. A sensitivity study with synthetic data evidences the capability of the method to retrieve aerosol properties such as size distribution and profiles of volume concentration (VC), especially for coarse particles. Aerosol properties obtained by the mentioned method are compared with airborne in-situ measurements acquired during two flights over Granada (Spain) within the framework of ChArMEx/ADRIMED (Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) 2013 campaign. The retrieved aerosol VC profiles agree well with the airborne measurements, showing a mean bias error (MBE) and a mean absolute bias error (MABE) of 0.3 μm3/cm3 (12%) and 5.8 μm3/cm3 (25%), respectively. The differences between retrieved VC and airborne in-situ measurements are within the uncertainty of GRASP retrievals. In addition, the retrieved VC at 2500 m a.s.l. is shown and compared with in-situ measurements obtained during summer 2016 at a high-atitude mountain station in the framework of the SLOPE I campaign (Sierra Nevada Lidar AerOsol Profiling Experiment). VC from GRASP presents high correlation (r = 0.91) with the in-situ measurements, but overestimates them, MBE and MABE being equal to 23% and 43%.

  19. A review of measurement-based assessments of the aerosol direct radiative effect and forcing

    Directory of Open Access Journals (Sweden)

    H. Yu

    2006-01-01

    contamination of the satellite derived aerosol field will reduce the TOA DRE to -5.0 Wm-2. Because of a lack of measurements of aerosol absorption and difficulty in characterizing land surface reflection, estimates of DRE over land and at the ocean surface are currently realized through a combination of satellite retrievals, surface measurements, and model simulations, and are less constrained. Over the oceans the surface DRE is estimated to be -8.8±0.7 Wm-2. Over land, an integration of satellite retrievals and model simulations derives a DRE of -4.9±0.7 Wm-2 and -11.8±1.9 Wm-2 at the TOA and surface, respectively. CTM simulations derive a wide range of DRE estimates that on average are smaller than the measurement-based DRE by about 30-40%, even after accounting for thin cirrus and cloud contamination. A number of issues remain. Current estimates of the aerosol direct effect over land are poorly constrained. Uncertainties of DRE estimates are also larger on regional scales than on a global scale and large discrepancies exist between different approaches. The characterization of aerosol absorption and vertical distribution remains challenging. The aerosol direct effect in the thermal infrared range and in cloudy conditions remains relatively unexplored and quite uncertain, because of a lack of global systematic aerosol vertical profile measurements. A coordinated research strategy needs to be developed for integration and assimilation of satellite measurements into models to constrain model simulations. Enhanced measurement capabilities in the next few years and high-level scientific cooperation will further advance our knowledge.

  20. Synergy of Satellite-Surface Observations for Studying the Properties of Absorbing Aerosols in Asia

    Science.gov (United States)

    Tsay, Si-Chee

    2010-01-01

    Through interaction with clouds and alteration of the Earth's radiation budget, atmospheric aerosols significantly influence our weather and climate. Monsoon rainfalls, for example, sustain the livelihood of more than half of the world's population. Thus, understanding the mechanism that drives the water cycle and freshwater distribution is high-lighted as one of the major near-term goals in NASA's Earth Science Enterprise Strategy. Every cloud droplet/ice-crystal that serves as an essential element in portraying water cycle and distributing freshwater contains atmospheric aerosols at its core. In addition, the spatial and temporal variability of atmospheric aerosol properties is complex due to their dynamic nature. In fact, the predictability of the tropical climate system is much reduced during the boreal spring, which is associated with the peak season of biomass burning activities and regional/long-range transport of dust aerosols. Therefore, to accurately assess the impact of absorbing aerosols on regional-to-global climate requires not only modeling efforts but also continuous observations from satellites, aircraft, networks of ground-based instruments and dedicated field experiments. Since 1997 NASA has been successfully launching a series of satellites the Earth Observing System - to intensively study, and gain a better understanding of, the Earth as an integrated system. Through participation in many satellite remote-sensing/retrieval and validation projects over the years, we have gradually developed and refined the SMART (Surface-sensing Measurements for Atmospheric Radiative Transfer) and COMMIT (Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile observatories, a suite of surface remote sensing and in-situ instruments that proved to be vital in providing high temporal measurements, which complement the satellite observations. In this talk, we will present SMART-COMMIT which has played key roles, serving as network or supersite

  1. Estimation of Downwelling Surface Longwave Radiation under Heavy Dust Aerosol Sky

    Directory of Open Access Journals (Sweden)

    Chunlei Wang

    2017-02-01

    Full Text Available The variation of aerosols, especially dust aerosol, in time and space plays an important role in climate forcing studies. Aerosols can effectively reduce land surface longwave emission and re-emit energy at a colder temperature, which makes it difficult to estimate downwelling surface longwave radiation (DSLR with satellite data. Using the latest atmospheric radiative transfer code (MODTRAN 5.0, we have simulated the outgoing longwave radiation (OLR and DSLR under different land surface types and atmospheric profile conditions. The results show that dust aerosol has an obvious “warming” effect to longwave radiation compared with other aerosols; that aerosol longwave radiative forcing (ALRF increased with the increasing of aerosol optical depth (AOD; and that the atmospheric water vapor content (WVC is critical to the understanding of ALRF. A method is proposed to improve the accuracy of DSLR estimation from satellite data for the skies under heavy dust aerosols. The AOD and atmospheric WVC under cloud-free conditions with a relatively simple satellite-based radiation model yielding the high accurate DSLR under heavy dust aerosol are used explicitly as model input to reduce the effects of dust aerosol on the estimation of DSLR. Validations of the proposed model with satellites data and field measurements show that it can estimate the DSLR accurately under heavy dust aerosol skies. The root mean square errors (RMSEs are 20.4 W/m2 and 24.2 W/m2 for Terra and Aqua satellites, respectively, at the Yingke site, and the biases are 2.7 W/m2 and 9.6 W/m2, respectively. For the Arvaikheer site, the RMSEs are 23.2 W/m2 and 19.8 W/m2 for Terra and Aqua, respectively, and the biases are 7.8 W/m2 and 10.5 W/m2, respectively. The proposed method is especially applicable to acquire relatively high accurate DSLR under heavy dust aerosol using MODIS data with available WVC and AOD data.

  2. Seasonal fluctuations of the uranium and thorium contents in aerosols in surface air

    International Nuclear Information System (INIS)

    Kolb, W.

    1985-01-01

    An estimate in the UNSCEAR report the only source considered for the uranium and thorium contents is ground dust. A significant portion of the aerosols, however, comes from chimneys. Aerosol samples taken monthly in Brunswick, Berlin, Skibotn (Northern Norway) were, therefore, scrutinized alpha-spectrometrically for U-238, U-234, Th-230, and Th-232. The activity concentration in surface air of Northern Norway is only about 30 nBq/cm 3 . In Brunswick and Berlin, the concentration was higher by a factor of one to two due to the higher specific activity of the mineral aerosols. Significant differences of the isotope ratios allow conclusions as to the origin of the aerosols. The activity concentrations measured and their seasonal fluctuations must be taken into account in the evaluation of environment monitoring of nuclear fuel factories. (orig./HP) [de

  3. MODIFICATION OF SURFACE KONDENSITSIONNYH AEROSOLS WELDING AND METALLURGICHESKIH PRODUCTIONS

    Directory of Open Access Journals (Sweden)

    A. A. Ennan

    2016-04-01

    Full Text Available Chemical modification of surface kondensitsionnyh aerosols (KA which formation when heat treatment metals (process of weld, foundry processes with application chlorosilanes are suggested. Adsorbtion vapor of water on modification powders KA decreases and changes in varies from modifier and conditions modification are setted.

  4. Insight into Chemistry on Cloud/Aerosol Water Surfaces.

    Science.gov (United States)

    Zhong, Jie; Kumar, Manoj; Francisco, Joseph S; Zeng, Xiao Cheng

    2018-05-15

    Cloud/aerosol water surfaces exert significant influence over atmospheric chemical processes. Atmospheric processes at the water surface are observed to follow mechanisms that are quite different from those in the gas phase. This Account summarizes our recent findings of new reaction pathways on the water surface. We have studied these surface reactions using Born-Oppenheimer molecular dynamics simulations. These studies provide useful information on the reaction time scale, the underlying mechanism of surface reactions, and the dynamic behavior of the product formed on the aqueous surface. According to these studies, the aerosol water surfaces confine the atmospheric species into a specific orientation depending on the hydrophilicity of atmospheric species or the hydrogen-bonding interactions between atmospheric species and interfacial water. As a result, atmospheric species are activated toward a particular reaction on the aerosol water surface. For example, the simplest Criegee intermediate (CH 2 OO) exhibits high reactivity toward the interfacial water and hydrogen sulfide, with the reaction times being a few picoseconds, 2-3 orders of magnitude faster than that in the gas phase. The presence of interfacial water molecules induces proton-transfer-based stepwise pathways for these reactions, which are not possible in the gas phase. The strong hydrophobicity of methyl substituents in larger Criegee intermediates (>C1), such as CH 3 CHOO and (CH 3 ) 2 COO, blocks the formation of the necessary prereaction complexes for the Criegee-water reaction to occur at the water droplet surface, which lowers their proton-transfer ability and hampers the reaction. The aerosol water surface provides a solvent medium for acids (e.g., HNO 3 and HCOOH) to participate in reactions via mechanisms that are different from those in the gas and bulk aqueous phases. For example, the anti-CH 3 CHOO-HNO 3 reaction in the gas phase follows a direct reaction between anti-CH 3 CHOO and HNO 3

  5. Estimation of aerosol water and chemical composition from AERONET Sun-sky radiometer measurements at Cabauw, the Netherlands

    NARCIS (Netherlands)

    Van Beelen, A. J.; Roelofs, G. J H; Hasekamp, O. P.; Henzing, J. S.; Röckmann, T.

    2014-01-01

    Remote sensing of aerosols provides important information on atmospheric aerosol abundance. However, due to the hygroscopic nature of aerosol particles observed aerosol optical properties are influenced by atmospheric humidity, and the measurements do not unambiguously characterize the aerosol dry

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

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Timothy Onasch

    2009-09-09

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

  7. Aerosol Retrieval Sensitivity and Error Analysis for the Cloud and Aerosol Polarimetric Imager on Board TanSat: The Effect of Multi-Angle Measurement

    Directory of Open Access Journals (Sweden)

    Xi Chen

    2017-02-01

    Full Text Available Aerosol scattering is an important source of error in CO2 retrievals from satellite. This paper presents an analysis of aerosol information content from the Cloud and Aerosol Polarimetric Imager (CAPI onboard the Chinese Carbon Dioxide Observation Satellite (TanSat to be launched in 2016. Based on optimal estimation theory, aerosol information content is quantified from radiance and polarization observed by CAPI in terms of the degrees of freedom for the signal (DFS. A linearized vector radiative transfer model is used with a linearized Mie code to simulate observation and sensitivity (or Jacobians with respect to aerosol parameters. In satellite nadir mode, the DFS for aerosol optical depth is the largest, but for mode radius, it is only 0.55. Observation geometry is found to affect aerosol DFS based on the aerosol scattering phase function from the comparison between different viewing zenith angles or solar zenith angles. When TanSat is operated in target mode, we note that multi-angle retrieval represented by three along-track measurements provides additional 0.31 DFS on average, mainly from mode radius. When adding another two measurements, the a posteriori error decreases by another 2%–6%. The correlation coefficients between retrieved parameters show that aerosol is strongly correlated with surface reflectance, but multi-angle retrieval can weaken this correlation.

  8. Inverse modeling of cloud-aerosol interactions -- Part 1: Detailed response surface analysis

    NARCIS (Netherlands)

    Partridge, D.G.; Vrugt, J.A.; Tunved, P.; Ekman, A.M.L.; Gorea, D.; Sooroshian, A.

    2011-01-01

    New methodologies are required to probe the sensitivity of parameters describing cloud droplet activation. This paper presents an inverse modeling-based method for exploring cloud-aerosol interactions via response surfaces. The objective function, containing the difference between the measured and

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

    Science.gov (United States)

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

    2012-02-01

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

  10. LIDAR Measurements of the Vertical Distribution of Aerosol Optical and Physical Properties over Central Asia

    Science.gov (United States)

    The vertical structure of aerosol optical and physical properties was measured by Lidar in Eastern Kyrgyzstan, Central Asia, from June 2008 to May 2009. Lidar measurements were supplemented with surface-based measurements of PM2.5 and PM10 mass and chemical ...

  11. Comprehensive Measurement of Atmospheric Aerosols with a Wide Range Aerosol Spectrometer

    International Nuclear Information System (INIS)

    Keck, L; Pesch, M; Grimm, H

    2011-01-01

    A wide range aerosol spectrometer (WRAS) was used for comprehensive long term measurements of aerosol size distributions. The system combines the results of an optical aerosol spectrometer with the results of a Scanning Mobility Particle Sizer (SMPS) to record essentially the full size range (5 nm - 32 μm) of atmospheric particles in 72 channels. Measurements were carried out over one year (2009) at the Global Atmospheric Watch (GAW)-Station Hohenpeissenberg, Bavaria. Total particle number concentrations obtained from the aerosol size distributions were compared to the total number concentrations measured by a Condensation Particle Counter (CPC). The comparison showed an excellent agreement of the data. The high time resolution of 5 minutes allows the combination of the measured size distributions with meteorological data and correlations to gaseous pollutants (CO, NOx and SO2). A good correlation of particle number and CO concentrations was found for long distance transported small particles, which were probably mainly soot particles. Correlations to NOx were observed for aerosols from local sources such as traffic emissions. The formation of secondary aerosols from gaseous precursors was also observed. Episodes of relatively high concentration of particles in the range of 2-3 μm were probably caused by pollen.

  12. First surface-based estimation of the aerosol indirect effect over a site in southeastern China

    Science.gov (United States)

    Liu, Jianjun; Li, Zhanqing

    2018-02-01

    The deployment of the U.S. Atmospheric Radiation Measurement mobile facility in Shouxian from May to December 2008 amassed the most comprehensive set of measurements of atmospheric, surface, aerosol, and cloud variables in China. This deployment provided a unique opportunity to investigate the aerosol-cloud interactions, which are most challenging and, to date, have not been examined to any great degree in China. The relationship between cloud droplet effective radius (CER) and aerosol index (AI) is very weak in summer because the cloud droplet growth is least affected by the competition for water vapor. Mean cloud liquid water path (LWP) and cloud optical depth (COD) significantly increase with increasing AI in fall. The sensitivities of CER and LWP to aerosol loading increases are not significantly different under different air mass conditions. There is a significant correlation between the changes in hourly mean AI and the changes in hourly mean CER, LWP, and COD. The aerosol first indirect effect (FIE) is estimated in terms of relative changes in both CER (FIECER) and COD (FIECOD) with changes in AI for different seasons and air masses. FIECOD and FIECER are similar in magnitude and close to the typical FIE value of ˜ 0.23, and do not change much between summer and fall or between the two different air mass conditions. Similar analyses were done using spaceborne Moderate Resolution Imaging Spectroradiometer data. The satellite-derived FIE is contrary to the FIE estimated from surface retrievals and may have large uncertainties due to some inherent limitations.

  13. Long-term Aerosol Lidar Measurements At CNR-IMAA

    Science.gov (United States)

    Mona, L.; Amodeo, A.; D'Amico, G.; Pandolfi, M.; Pappalardo, G.

    2006-12-01

    Actual estimations of the aerosol effect on the radiation budget are affected by a large uncertainties mainly due to the high inhomogeneity and variability of atmospheric aerosol, in terms of concentration, shape, size distribution, refractive index and vertical distribution. Long-term measurements of vertical profiles of aerosol optical properties are needed to reduce these uncertainties. At CNR-IMAA (40° 36'N, 15° 44' E, 760 m above sea level), a lidar system for aerosol study is operative since May 2000 in the framework of EARLINET (European Aerosol Research Lidar Network). Until August 2005, it provided independent measurements of aerosol extinction and backscatter at 355 nm and aerosol backscatter profiles at 532 nm. After an upgrade of the system, it provides independent measurements of aerosol extinction and backscatter profiles at 355 and 532 nm, and of aerosol backscatter profiles at 1064 nm and depolarization ratio at 532 nm. For these measurements, lidar ratio at 355 and 532 nm and Angstrom exponent profiles at 355/532 nm are also obtained. Starting on May 2000, systematic measurements are performed three times per week according to the EARLINET schedule and further measurements are performed in order to investigate particular events, like dust intrusions, volcanic eruptions and forest fires. A climatological study has been carried out in terms of the seasonal behavior of the PBL height and of the aerosol optical properties calculated inside the PBL itself. In the free troposphere, an high occurrences of Saharan dust intrusions (about 1 day of Saharan dust intrusion every 10 days) has been observed at CNR-IMAA because of the short distance from the Sahara region. During 6 years of observations, very peculiar cases of volcanic aerosol emitted by Etna volcano and aerosol released by large forest fires burning occurred in Alaska and Canada have been observed in the free troposphere at our site. Particular attention is devoted to lidar ratio both for the

  14. Real-time measurement of aerosol particle concentration at high temperatures; Hiukkaspitoisuuden reaaliaikainen mittaaminen korkeassa laempoetilassa

    Energy Technology Data Exchange (ETDEWEB)

    Keskinen, J; Hautanen, J; Laitinen, A [Tampere Univ. of Technology (Finland). Physics

    1997-10-01

    The aim of this project is to develop a new method for continuous aerosol particle concentration measurement at elevated temperatures (up to 800-1000 deg C). The measured property of the aerosol particles is the so called Fuchs surface area. This quantity is relevant for diffusion limited mass transfer to particles. The principle of the method is as follows. First, aerosol particles are charged electrically by diffusion charging process. The charging takes place at high temperature. After the charging, aerosol is diluted and cooled. Finally, aerosol particles are collected and the total charge carried by the aerosol particles is measured. Particle collection and charge measurement take place at low temperature. Benefits of this measurement method are: particles are charged in-situ, charge of the particles is not affected by the temperature and pressure changes after sampling, particle collection and charge measurement are carried out outside the process conditions, and the measured quantity is well defined. The results of this study can be used when the formation of the fly ash particles is studied. Another field of applications is the study and the development of gasification processes. Possibly, the method can also be used for the monitoring the operation of the high temperature particle collection devices. (orig.)

  15. Radioactive Aerosol Size Distribution Measured in Nuclear Workplaces

    International Nuclear Information System (INIS)

    Kravchik, T.; Oved, S.; German, U.

    2002-01-01

    Inhalation is the main route for internal exposure of workers to radioactive aerosols in the nuclear industry.Aerosol's size distribution and in particular its activity median aerodynamic diameter (AMAD)is important for determining the fractional deposition of inhaled particles in the respiratory tract and the resulting doses. Respiratory tract models have been published by the International Commission on radiological Protection (ICRP).The former model has recommended a default AMAD of 1 micron for the calculation of dose coefficients for workers in the nuclear industry [1].The recent model recommends a 5 microns default diameter for occupational exposure which is considered to be more representative of workplace aerosols [2]. Several researches on radioactive aerosol's size distribution in nuclear workplaces has supported this recommendation [3,4].This paper presents the results of radioactive aerosols size distribution measurements taken at several workplaces of the uranium production process

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

    Science.gov (United States)

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

    2002-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Mielonen, T.

    2010-07-01

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

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

    Directory of Open Access Journals (Sweden)

    B. H. Lee

    2010-12-01

    Full Text Available A variable residence time thermodenuder (TD was combined with an Aerodyne Aerosol Mass Spectrometer (AMS and a Scanning Mobility Particle Sizer (SMPS to measure the volatility distribution of aged organic aerosol in the Eastern Mediterranean during the Finokalia Aerosol Measurement Experiment in May of 2008 (FAME-2008. A new method for the quantification of the organic aerosol volatility distribution was developed combining measurements of all three instruments together with an aerosol dynamics model.

    Challenges in the interpretation of ambient thermodenuder-AMS measurements include the potential resistances to mass transfer during particle evaporation, the effects of particle size on the evaporated mass fraction, the changes in the AMS collection efficiency and particle density as the particles evaporate partially in the TD, and finally potential losses inside the TD. Our proposed measurement and data analysis method accounts for all of these problems combining the AMS and SMPS measurements.

    The AMS collection efficiency of the aerosol that passed through the TD was found to be approximately 10% lower than the collection efficiency of the aerosol that passed through the bypass. The organic aerosol measured at Finokalia is approximately 2 or more orders of magnitude less volatile than fresh laboratory-generated monoterpene (α-pinene, β-pinene and limonene under low NOx conditions secondary organic aerosol. This low volatility is consistent with its highly oxygenated AMS mass spectrum. The results are found to be highly sensitive to the mass accommodation coefficient of the evaporating species. This analysis is based on the assumption that there were no significant reactions taking place inside the thermodenuder.

  19. Photoacoustic measurements of photokinetics in single optically trapped aerosol droplets

    Science.gov (United States)

    Covert, Paul; Cremer, Johannes; Signorell, Ruth; Thaler, Klemens; Haisch, Christoph

    2017-04-01

    It is well established that interaction of light with atmospheric aerosols has a large impact on the Earth's climate. However, uncertainties in the magnitude of this impact remain large, due in part to broad distributions of aerosol size, composition, and chemical reactivity. In this context, photoacoustic spectroscopy is commonly used to measure light absorption by aerosols. Here, we present photoacoustic measurements of single, optically-trapped nanodroplets to reveal droplet size-depencies of photochemical and physical processes. Theoretical considerations have pointed to a size-dependence in the magnitude and phase of the photoacoustic response from aerosol droplets. This dependence is thought to originate from heat transfer processes that are slow compared to the acoustic excitation frequency. In the case of a model aerosol, our measurements of single particle absorption cross-section versus droplet size confirm these theoretical predictions. In a related study, using the same model aerosol, we also demonstrate a droplet size-dependence of photochemical reaction rates [1]. Within sub-micron sized particles, photolysis rates were observed to be an order of magnitude greater than those observed in larger droplets. [1] J. W. Cremer, K. M. Thaler, C. Haisch, and R. Signorell. Photoacoustics of single laser-trapped nanodroplets for the direct observation of nanofocusing in aerosol photokinetics. Nat. Commun., 7:10941, 2016.

  20. Tethered balloon-borne aerosol measurements: seasonal and vertical variations of aerosol constituents over Syowa Station, Antarctica

    Directory of Open Access Journals (Sweden)

    K. Hara

    2013-09-01

    Full Text Available Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica, during the 46th Japanese Antarctic expedition (2005–2006. Direct aerosol sampling was operated from near the surface to the lower free troposphere (approximately 2500 m using a balloon-borne aerosol impactor. Individual aerosol particles were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Seasonal and vertical features of aerosol constituents and their mixing states were investigated. Results show that sulfate particles were predominant in the boundary layer and lower free troposphere in summer, whereas sea-salt particles were predominant during winter through spring. Minerals, MgSO4, and sulfate containing K were identified as minor aerosol constituents in both boundary layer and free troposphere over Syowa Station. Although sea-salt particles were predominant during winter through spring, the relative abundance of sulfate particles increased in the boundary layer when air masses fell from the free troposphere over the Antarctic coast and continent. Sea-salt particles were modified considerably through heterogeneous reactions with SO42− CH3SO3− and their precursors during summer, and were modified slightly through heterogeneous reactions with NO3− and its precursors. During winter through spring, sea-salt modification was insignificant, particularly in the cases of high relative abundance of sea-salt particles and higher number concentrations. In August, NO3− and its precursors contributed greatly to sea-salt modification over Syowa Station. Because of the occurrence of sea-salt fractionation on sea ice, Mg-rich sea-salt particles were identified during the months of April through November. In contrast, Mg-free sea-salt particles and slightly Mg-rich sea-salt particles coexisted in the lower troposphere during summer. Thereby, Mg separation can proceed by sea-salt fractionation during summer in

  1. Aerosol distribution measurements by laser - Doppler - spectroscopy

    International Nuclear Information System (INIS)

    Baldassari, J.

    1977-01-01

    Laser-Doppler-Spectroscopy is used to study particle size distribution, especially sodium aerosols, in the presence of uncondensable gases. Theoretical basis are given, and an experimental technique is described. First theoretical results show reasonably good agreement with experimental data available; this method seems to be a promising one. (author)

  2. Secondary Aerosol Formation over the ESCOMPTE Area: Results from airborne Aerosol and Trace Gas Measurements

    Science.gov (United States)

    van Dingenen, R.; Martins-Dos Santos, S.; Putaud, J. P.; Allet, C.; Bretton, E.; Perros, P.

    2003-04-01

    From June 10th to July 14th 2001, the ESCOMPTE campaign took place in the Marseille-Berre area in Southern France. The goal of the campaign was to produce a high quality 3-D data base from emissions, transport and air composition measurements during urban photochemical pollution episodes at the meso-scale. The CAATER AEROPLUM project was embedded within this international field campaign. AEROPLUM aimed at mapping size distributions of aerosols and photo-oxidants in the mixed layer over the ESCOMPTE domain, using the ARAT Fokker 27 as measurement platform. Aircraft sub-micrometer aerosol measurements are validated during overpasses against ground-based measurements, carried out with similar instrumentation. We will present and discuss data during periods of seabreeze, transporting coastal industrial and urban pollution land-inwards. This leads to intense photochemical activity, evidenced by elevated O_3 concentrations and aerosol levels.

  3. Dust Aerosols at the Source Region During ACE-ASIA: A Surface/Satellite Perspective

    Science.gov (United States)

    Tsay, Si-Chee; Lau, William K. M. (Technical Monitor)

    2001-01-01

    ACE (Aerosol Characterization Experiment)-Asia is designed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally occurring aerosols, which often exist in high concentrations over eastern Asia and along the rim of the western Pacific. The phase-I of ACE-Asia was conducted from March-May 2001 in the vicinity of the Gobi desert, East Coast of China, Yellow Sea, Korea, and Japan, along the pathway of Kosa (severe events that blanket East Asia with yellow desert dust, peaked in the Spring season). Asian dust typically originates in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian dust is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the mid-Pacific Ocean. During ACE-Asia we have measured continuously aerosol physical/optical/radiative properties, column precipitable water amount, and surface reflectivity over homogeneous areas from surface. The inclusion of flux measurements permits the determination of dust aerosol radiative flux in addition to measurements of loading and optical thickness. At the time of the Terra/MODIS, SeaWiFS, TOMS and other satellite overpasses, these ground-based observations can provide valuable data to compare with satellite retrievals over land. Preliminary results will be presented and discussed their implications in regional climatic effects.

  4. Lidar Measurements of Ozone, Aerosols, and Clouds Observed in the Tropics Near Central America During TC4-Costa Rica

    Science.gov (United States)

    Hair, J. W.; Browell, E.; Butler, C.; Fenn, M.; Notari, A.; Simpson, S.; Ismail, S.; Avery, M.

    2007-12-01

    Large-scale measurements of ozone and aerosol distributions were made from the NASA DC-8 aircraft during the TC4 (Tropical Composition, Cloud, and Climate Coupling) field experiment conducted from June 28 - August 10, 2007 based in San Jose, Costa Rica. Remote measurements were made with an airborne lidar to provide ozone and multiple-wavelength aerosol and cloud backscatter profiles from near the surface to above the tropopause along the flight track. Aerosol depolarization measurements were also made for the detection of nonspherical aerosols, such as mineral dust, biomass burning, and recent emissions from South American volcanoes. Long-range transport of Saharan dust with depolarizing aerosols was frequently observed in the lower troposphere both over the Caribbean Sea and Pacific Ocean and within the marine boundary layer. In addition, visible and sub-visible cirrus clouds were observed with the multi-wavelength backscatter and depolarization measurements. Initial distributions of ozone, aerosol, and cloud are presented which will be used to interpret large-scale atmospheric processes. In situ measurements of ozone and aerosols made onboard the DC-8 will be compared to the remote lidar measurements. This paper provides a first look at the characteristics of ozone, aerosol, and cloud distributions that were encountered during this field experiment and provide a unique dataset that will be further related through satellite data, backward trajectories, and chemical transport models (CTM) to sources and sinks of ozone, aerosols, and clouds and to dynamical, chemical, and radiative processes.

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

    Science.gov (United States)

    Pueschel, Rudolf F. (Editor)

    1991-01-01

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

  6. Measurement of size distribution for 220Rn progeny attached aerosols

    International Nuclear Information System (INIS)

    Zhang Lei; Guo Qiuju; Zhuo Weihai

    2008-01-01

    The size distribution of radioactive aerosols is a very important factor for evaluating the inner exposure dose contributed by radon and thoron progeny in environments. In order to measure the size distribution of thoron progeny attached radioactive aerosols, a device was developed using wire screens. The count median diameter (CMD) and the geometric standard deviation (GSD) of attached radioactive aerosols were calculated by collecting ThB and using CR-39 as detector. Field measurement results at Yangjiang City in Guangdong Province show that the CMDs distribute between 30 and 130 nm, and the GSDs are between 1.9 and 3.3. It also shows that the more humid country, the smaller CMDs, and the ventilation has great influence on the size distribution of aerosols. The CMDs of adobe house are smaller than that of the concrete houses. (authors)

  7. Aerosol size and chemical composition measurements at the Polar Environment Atmospheric Research Lab (PEARL) in Eureka, Nunavut

    Science.gov (United States)

    Hayes, P. L.; Tremblay, S.; Chang, R. Y. W.; Leaitch, R.; Kolonjari, F.; O'Neill, N. T.; Chaubey, J. P.; AboEl Fetouh, Y.; Fogal, P.; Drummond, J. R.

    2016-12-01

    This study presents observations of aerosol chemical composition and particle number size distribution at the Polar Environment Atmospheric Research Laboratory (PEARL) in the Canadian High Arctic (80N, 86W). The current aerosol measurement program at PEARL has been ongoing for more than a year providing long-term observations of Arctic aerosol size distributions for both coarse and fine modes. Particle nucleation events were frequently observed during the summers of 2015 and 2016. The size distribution data are also compared against similar measurements taken at the Alert Global Atmospheric Watch Observatory (82N, 62W) for July and August 2015. The nucleation events are correlated at the two sites, despite a distance of approximately 500 km, suggesting regional conditions favorable for particle nucleation and growth during this period. Size resolved chemical composition measurements were also carried out using an aerosol mass spectrometer. The smallest measured particles between 40 and 60 nm are almost entirely organic aerosol (OA) indicating that the condensation of organic vapors is responsible for particle growth events and possibly particle nucleation. This conclusion is further supported by the relatively high oxygen content of the OA, which is consistent with secondary formation of OA via atmospheric oxidation.Lastly, surface measurements of the aerosol scattering coefficient are compared against the coefficient values calculated using Mie theory and the measured aerosol size distribution. Both the actual and the calculated scattering coefficients are then compared to sun photometer measurements to understand the relationship between surface and columnar aerosol optical properties. The measurements at PEARL provide a unique combination of surface and columnar data sets on aerosols in the High Arctic, a region where such measurements are scarce despite the important impact of aerosols on Arctic climate.PEARL research is supported by the Natural Sciences and

  8. Chemical Thermodynamics of Aqueous Atmospheric Aerosols: Modeling and Microfluidic Measurements

    Science.gov (United States)

    Nandy, L.; Dutcher, C. S.

    2017-12-01

    Accurate predictions of gas-liquid-solid equilibrium phase partitioning of atmospheric aerosols by thermodynamic modeling and measurements is critical for determining particle composition and internal structure at conditions relevant to the atmosphere. Organic acids that originate from biomass burning, and direct biogenic emission make up a significant fraction of the organic mass in atmospheric aerosol particles. In addition, inorganic compounds like ammonium sulfate and sea salt also exist in atmospheric aerosols, that results in a mixture of single, double or triple charged ions, and non-dissociated and partially dissociated organic acids. Statistical mechanics based on a multilayer adsorption isotherm model can be applied to these complex aqueous environments for predictions of thermodynamic properties. In this work, thermodynamic analytic predictive models are developed for multicomponent aqueous solutions (consisting of partially dissociating organic and inorganic acids, fully dissociating symmetric and asymmetric electrolytes, and neutral organic compounds) over the entire relative humidity range, that represent a significant advancement towards a fully predictive model. The model is also developed at varied temperatures for electrolytes and organic compounds the data for which are available at different temperatures. In addition to the modeling approach, water loss of multicomponent aerosol particles is measured by microfluidic experiments to parameterize and validate the model. In the experimental microfluidic measurements, atmospheric aerosol droplet chemical mimics (organic acids and secondary organic aerosol (SOA) samples) are generated in microfluidic channels and stored and imaged in passive traps until dehydration to study the influence of relative humidity and water loss on phase behavior.

  9. The continuous field measurements of soluble aerosol compositions at the Taipei Aerosol Supersite, Taiwan

    Science.gov (United States)

    Chang, Shih-Yu; Lee, Chung-Te; Chou, Charles C.-K.; Liu, Shaw-Chen; Wen, Tian-Xue

    The characteristics of ambient aerosols, affected by solar radiation, relative humidity, wind speed, wind direction, and gas-aerosol interaction, changed rapidly at different spatial and temporal scales. In Taipei Basin, dense traffic emissions and sufficient solar radiation for typical summer days favored the formation of secondary aerosols. In winter, the air quality in Taipei Basin was usually affected by the Asian continental outflows due to the long-range transport of pollutants carried by the winter monsoon. The conventional filter-based method needs a long time for collecting aerosols and analyzing compositions, which cannot provide high time-resolution data to investigate aerosol sources, atmospheric transformation processes, and health effects. In this work, the in situ ion chromatograph (IC) system was developed to provide 15-min time-resolution data of nine soluble inorganic species (Cl -, NO 2-, NO 3-, SO 42-, Na +, NH 4+, K +, Mg 2+ and Ca 2+). Over 89% of all particles larger than approximately 0.056 μm were collected by the in situ IC system. The in situ IC system is estimated to have a limit of detection lower than 0.3 μg m -3 for the various ambient ionic components. Depending on the hourly measurements, the pollutant events with high aerosol concentrations in Taipei Basin were associated with the local traffic emission in rush hour, the accumulation of pollutants in the stagnant atmosphere, the emission of industrial pollutants from the nearby factories, the photochemical secondary aerosol formation, and the long-range transport of pollutants from Asian outflows.

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

    Science.gov (United States)

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

    2008-12-01

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

  11. The continuous monitoring of the artificial beta aerosol activity by measuring the alpha and beta activity in aerosol simultaneously

    International Nuclear Information System (INIS)

    Hayakawa, Hironobu; Oonishi, Masaki; Matsuura, Hiroyuki

    1990-01-01

    We have constructed the system to monitor the artificial beta aerosol activity around the nuclear power plants continuously in real time. The smaller releases of artificial radionuclides from the nuclear power plants can be lost in the fluctuations of the natural background of the beta aerosol activity, when only the beta activity of the aerosol is measured. This method to discriminate the artificial and the natural beta activity of the aerosol is based on the fact that the ratio of the natural alpha and beta activities of the aerosol is almost constant. The detection limit of this system is below 3 Bq/m 3 . (author)

  12. Aerosols on the surface of needles in the vicinity of Winterthur

    International Nuclear Information System (INIS)

    Wyttenbach, A.; Tobler, L.; Bajo, S.

    1991-01-01

    The composition and the mass of aerosols residing on the surface of one-year-old needles of Norway spruce are described. The composition of aerosols on spruce needles is compared with that of aerosols collected by air filters and the composition of the local soil. A comparison of the years 1982 and 1985 shows virtually identical conditions. Finally, possible connections between aerosol mass and inherent needle content are discussed. (author) 5 figs., 2 tabs., 13 refs

  13. Measurements of aerosol fluxes to Speulder forest using a micrometeorological technique

    DEFF Research Database (Denmark)

    Gallagher, M.W.; Beswick, K.M.; Duyzer, J.

    1997-01-01

    It has often been stated that micrometeorological and throughfall measurements of dry deposition differ by an order of magnitude with the results being highly variable and difficult to interpret or reconcile. We present measurements by the eddy correlation method of sub-micron aerosol deposition...... to a forest and show that they are large, typically 1 cm s(-1) or more. We compare the measurements with literature values obtained by throughfall and related techniques. The results, rather than being irreconcilable, show a clear and consistent behaviour in deposition velocity across the aerosol size...... spectrum, despite the very different techniques involved. There would appear to be a contradiction with previously assumed model predictions of aerosol deposition Velocity to forests and rough vegetated surfaces particularly for particles in the size range 0.1-1.0 mu m where collection efficiencies appear...

  14. Sun and aureole spectrometer for airborne measurements to derive aerosol optical properties.

    Science.gov (United States)

    Asseng, Hagen; Ruhtz, Thomas; Fischer, Jürgen

    2004-04-01

    We have designed an airborne spectrometer system for the simultaneous measurement of the direct Sun irradiance and aureole radiance. The instrument is based on diffraction grating spectrometers with linear image sensors. It is robust, lightweight, compact, and reliable, characteristics that are important for airborne applications. The multispectral radiation measurements are used to derive optical properties of tropospheric aerosols. We extract the altitude dependence of the aerosol volume scattering function and of the aerosol optical depth by using flight patterns with descents and ascents ranging from the surface level to the top of the boundary layer. The extinction coefficient and the product of single scattering albedo and phase function of separate layers can be derived from the airborne measurements.

  15. Dust, Pollution, and Biomass Burning Aerosols in Asian Pacific: A Column Surface/Satellite Perspective

    Science.gov (United States)

    Tsay, Si-Chee; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Many recent field experiments are designed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally occurring aerosols, which often exist in high concentrations over eastern/southeastern Asia and along the rim of the western Pacific. For example, the phase-I of ACE-Asia was conducted from March-May 2001 in the vicinity of the Gobi desert, East Coast of China, Yellow Sea, Korea, and Japan, along the pathway of Kosa (severe events that blanket East Asia with yellow desert dust, peaked in the Spring season). Asian dust typically originates in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Springtime is also the peak season for biomass burning in southeastern Asia. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian aerosols is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the mid-Pacific Ocean. During ACE-Asia we have measured continuously aerosol physical/optical/radiative properties, column precipitable water amount, and surface reflectivity over homogeneous areas from surface. The inclusion of flux measurements permits the determination of aerosol radiative flux in addition to measurements of loading and optical depth. At the time of the Terra/MODIS (Moderate Resolution Imaging Spectroradiometer), SeaWiFS (Sea-viewing Wide Field-of-view Sensor), TOMS (Total Ozone Mapping Spectrometer) and other satellite overpasses, these ground-based observations can provide valuable data to compare with satellite retrievals over land. A column satellite-surface perspective of Asian aerosols will be presented

  16. Aerosol light absorption and its measurement: A review

    International Nuclear Information System (INIS)

    Moosmueller, H.; Chakrabarty, R.K.; Arnott, W.P.

    2009-01-01

    Light absorption by aerosols contributes to solar radiative forcing through absorption of solar radiation and heating of the absorbing aerosol layer. Besides the direct radiative effect, the heating can evaporate clouds and change the atmospheric dynamics. Aerosol light absorption in the atmosphere is dominated by black carbon (BC) with additional, significant contributions from the still poorly understood brown carbon and from mineral dust. Sources of these absorbing aerosols include biomass burning and other combustion processes and dust entrainment. For particles much smaller than the wavelength of incident light, absorption is proportional to the particle volume and mass. Absorption can be calculated with Mie theory for spherical particles and with more complicated numerical methods for other particle shapes. The quantitative measurement of aerosol light absorption is still a challenge. Simple, commonly used filter measurements are prone to measurement artifacts due to particle concentration and modification of particle and filter morphology upon particle deposition, optical interaction of deposited particles and filter medium, and poor angular integration of light scattered by deposited particles. In situ methods measure particle absorption with the particles in their natural suspended state and therefore are not prone to effects related to particle deposition and concentration on filters. Photoacoustic and refractive index-based measurements rely on the heating of particles during light absorption, which, for power-modulated light sources, causes an acoustic signal and modulation of the refractive index in the air surrounding the particles that can be quantified with a microphone and an interferometer, respectively. These methods may suffer from some interference due to light-induced particle evaporation. Laser-induced incandescence also monitors particle heating upon absorption, but heats absorbing particles to much higher temperatures to quantify BC mass

  17. Preliminary results of aerosols' properties studied with EPF measurements from the SPICAM/UV instrument

    Science.gov (United States)

    Willame, Yannick; Carine Vandaele, Ann; Depiesse, Cedric; Gillotay, Didier; Kochenova, Svetlana; Montmessin, Franck

    2013-04-01

    Aerosols on Mars have an important impact on the radiative transfer properties of its atmosphere. Today their spectral properties and therefore their interaction with UV radiation are only poorly known. Improving the radiative transfer modeling requires a better knowledge of their characteristics, in particular of their opacity, phase function and single scattering albedo. Part of such information can be accessed by using EPF observations. The SPICAM instrument on board of the Mars-Express satellite is a 2 channel spectrometer. One channel operates in the ultraviolet (118-320 nm) and the second one in the infrared (1.0-1.7μm). SPICAM has been orbiting around the red planet since 2003 and has thus provided a large set of data. The instrument is capable of measuring under different geometries (nadir, limb, occultation) and one of them, called EPF (Emission Phase Function), can be a tool to study aerosols' properties. We have developed a new retrieval algorithm for nadir measurements based on the radiative transfer model LIDORT. This new code performs simulations of spectra taking into account gas absorption, surface reflection and scattering by aerosols and gases. The retrieval method, based on the optimal estimation, allows us up to now to deduce the ozone column density, the aerosols' optical depth and the surface albedo (with fixed wavelength dependencies). We are developing our model further in order to better study the aerosols' characteristics using EPF observations, which consist in looking at the same point on the planet while the satellite moves along the orbit. As the attempt to study all the aerosols' properties simultaneously was not convincing, we started studying their opacity and the influence of its altitude distribution with the other characteristics fixed. We will present preliminary results of our study on aerosols' properties using EPF data from SPICAM.

  18. Analysis of remotely sensed and surface data of aerosols and meteorology for the Mexico Megalopolis Area between 2003 and 2015.

    Science.gov (United States)

    Mora, Marco; Braun, Rachel A; Shingler, Taylor; Sorooshian, Armin

    2017-08-27

    This paper presents an aerosol characterization study from 2003 to 2015 for the Mexico City Metropolitan Area using remotely sensed aerosol data, ground-based measurements, air mass trajectory modeling, aerosol chemical composition modeling, and reanalysis data for the broader Megalopolis of Central Mexico region. The most extensive biomass burning emissions occur between March and May concurrent with the highest aerosol optical depth, ultraviolet aerosol index, and surface particulate matter (PM) mass concentration values. A notable enhancement in coarse PM levels is observed during vehicular rush hour periods on weekdays versus weekends owing to nonengine-related emissions such as resuspended dust. Among wet deposition species measured, PM 2.5 , PM 10 , and PM coarse (PM 10 -PM 2.5 ) were best correlated with NH 4 + , SO 4 2- , and Ca 2+ , suggesting that the latter three constituents are important components of the aerosol seeding raindrops that eventually deposit to the surface in the study region. Reductions in surface PM mass concentrations were observed in 2014-2015 owing to reduced regional biomass burning as compared to 2003-2013.

  19. Extinction efficiencies of coated absorbing aerosols measured by cavity ring down aerosol spectrometry

    Directory of Open Access Journals (Sweden)

    E. Segre

    2008-03-01

    Full Text Available In this study, we measure the extinction efficiency at 532 nm of absorbing aerosol particles coated with a non-absorbing solid and liquid organic shell with coating thickness varying between 5 and 100 nm using cavity ring down aerosol spectrometry. For this purpose, we use nigrosin, an organic black dye, as a model absorbing core and two non-absorbing organic substances as shells, glutaric acid (GA and Di-Ethyl-Hexyl-Sebacate (DEHS. The measured behavior of the coated particles is consistent with Mie calculations of core-shell particles. Errors between measured and calculated values for nigrosin coated with GA and DEHS are between 0.5% and 10.5% and between 0.5% and 9%, respectively. However, it is evident that the calculations are in better agreement with the measured results for thinner coatings. Possible reasons for these discrepancies are discussed.

  20. RETRIEVAL OF AEROSOL MICROPHYSICAL PROPERTIES BASED ON THE OPTIMAL ESTIMATION METHOD: INFORMATION CONTENT ANALYSIS FOR SATELLITE POLARIMETRIC REMOTE SENSING MEASUREMENTS

    Directory of Open Access Journals (Sweden)

    W. Z. Hou

    2018-04-01

    Full Text Available This paper evaluates the information content for the retrieval of key aerosol microphysical and surface properties for multispectral single-viewing satellite polarimetric measurements cantered at 410, 443, 555, 670, 865, 1610 and 2250 nm over bright land. To conduct the information content analysis, the synthetic data are simulated by the Unified Linearized Vector Radiative Transfer Model (UNLVTM with the intensity and polarization together over bare soil surface for various scenarios. Following the optimal estimation theory, a principal component analysis method is employed to reconstruct the multispectral surface reflectance from 410 nm to 2250 nm, and then integrated with a linear one-parametric BPDF model to represent the contribution of polarized surface reflectance, thus further to decouple the surface-atmosphere contribution from the TOA measurements. Focusing on two different aerosol models with the aerosol optical depth equal to 0.8 at 550 nm, the total DFS and DFS component of each retrieval aerosol and surface parameter are analysed. The DFS results show that the key aerosol microphysical properties, such as the fine- and coarse-mode columnar volume concentration, the effective radius and the real part of complex refractive index at 550 nm, could be well retrieved with the surface parameters simultaneously over bare soil surface type. The findings of this study can provide the guidance to the inversion algorithm development over bright surface land by taking full use of the single-viewing satellite polarimetric measurements.

  1. Retrieval of Aerosol Microphysical Properties Based on the Optimal Estimation Method: Information Content Analysis for Satellite Polarimetric Remote Sensing Measurements

    Science.gov (United States)

    Hou, W. Z.; Li, Z. Q.; Zheng, F. X.; Qie, L. L.

    2018-04-01

    This paper evaluates the information content for the retrieval of key aerosol microphysical and surface properties for multispectral single-viewing satellite polarimetric measurements cantered at 410, 443, 555, 670, 865, 1610 and 2250 nm over bright land. To conduct the information content analysis, the synthetic data are simulated by the Unified Linearized Vector Radiative Transfer Model (UNLVTM) with the intensity and polarization together over bare soil surface for various scenarios. Following the optimal estimation theory, a principal component analysis method is employed to reconstruct the multispectral surface reflectance from 410 nm to 2250 nm, and then integrated with a linear one-parametric BPDF model to represent the contribution of polarized surface reflectance, thus further to decouple the surface-atmosphere contribution from the TOA measurements. Focusing on two different aerosol models with the aerosol optical depth equal to 0.8 at 550 nm, the total DFS and DFS component of each retrieval aerosol and surface parameter are analysed. The DFS results show that the key aerosol microphysical properties, such as the fine- and coarse-mode columnar volume concentration, the effective radius and the real part of complex refractive index at 550 nm, could be well retrieved with the surface parameters simultaneously over bare soil surface type. The findings of this study can provide the guidance to the inversion algorithm development over bright surface land by taking full use of the single-viewing satellite polarimetric measurements.

  2. Aerosol optical properties over the Svalbard region of Arctic: ground-based measurements and satellite remote sensing

    Science.gov (United States)

    Gogoi, Mukunda M.; Babu, S. Suresh

    2016-05-01

    In view of the increasing anthropogenic presence and influence of aerosols in the northern polar regions, long-term continuous measurements of aerosol optical parameters have been investigated over the Svalbard region of Norwegian Arctic (Ny-Ålesund, 79°N, 12°E, 8 m ASL). This study has shown a consistent enhancement in the aerosol scattering and absorption coefficients during spring. The relative dominance of absorbing aerosols is more near the surface (lower single scattering albedo), compared to that at the higher altitude. This is indicative of the presence of local anthropogenic activities. In addition, long-range transported biomass burning aerosols (inferred from the spectral variation of absorption coefficient) also contribute significantly to the higher aerosol absorption in the Arctic spring. Aerosol optical depth (AOD) estimates from ground based Microtop sun-photometer measurements reveals that the columnar abundance of aerosols reaches the peak during spring season. Comparison of AODs between ground based and satellite remote sensing indicates that deep blue algorithm of Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals over Arctic snow surfaces overestimate the columnar AOD.

  3. Aerosol direct effect on solar radiation over the eastern Mediterranean Sea based on AVHRR satellite measurements

    Science.gov (United States)

    Georgakaki, Paraskevi; Papadimas, Christos D.; Hatzianastassiou, Nikos; Fotiadi, Aggeliki; Matsoukas, Christos; Stackhouse, Paul; Kanakidou, Maria; Vardavas, Ilias M.

    2017-04-01

    Despite the improved scientific understanding of the direct effect of aerosols on solar radiation (direct radiative effect, DRE) improvements are necessary, for example regarding the accuracy of the magnitude of estimated DREs and their spatial and temporal variability. This variability cannot be ensured by in-situ surface and airborne measurements, while it is also relatively difficult to capture through satellite observations. This becomes even more difficult when complete spatial coverage of extended areas is required, especially concerning areas that host various aerosol types with variable physico-chemical and optical aerosol properties. Better assessments of aerosol DREs are necessary, relying on aerosol optical properties with high spatial and temporal variation. The present study aims to provide a refined, along these lines, assessment of aerosol DREs over the eastern Mediterranean (EM) Sea, which is a key area for aerosol studies. Daily DREs are computed for 1˚ x1˚ latitude-longitude grids with the FORTH detailed spectral radiation transfer model (RTM) using input data for various atmospheric and surface parameters, such as clouds, water vapor, ozone and surface albedo, taken from the NASA-Langley Global Earth Observing System (GEOS) database. The model spectral aerosol optical depth (AOD), single scattering albedo and asymmetry parameter are taken from the Global Aerosol Data Set and the NOAA Climate Data Record (CDR) version 2 of Advanced Very High resolution Radiometer (AVHRR) AOD dataset which is available over oceans at 0.63 microns and at 0.1˚ x0.1˚ . The aerosol DREs are computed at the surface, the top-of-atmosphere and within the atmosphere, over the period 1985-1995. Preliminary model results for the period 1990-1993 reveal a significant spatial and temporal variability of DREs over the EM Sea, for example larger values over the Aegean and Black Seas, surrounded by land areas with significant anthropogenic aerosol sources, and over the

  4. Citizen-Enabled Aerosol Measurements for Satellites (CEAMS): A Network for High-Resolution Measurements of PM2.5 and Aerosol Optical Depth

    Science.gov (United States)

    Pierce, J. R.; Volckens, J.; Ford, B.; Jathar, S.; Long, M.; Quinn, C.; Van Zyl, L.; Wendt, E.

    2017-12-01

    Atmospheric particulate matter with diameter smaller than 2.5 μm (PM2.5) is a pollutant that contributes to the development of human disease. Satellite-derived estimates of surface-level PM2.5 concentrations have the potential to contribute greatly to our understanding of how particulate matter affects health globally. However, these satellite-derived PM2.5 estimates are often uncertain due to a lack of information about the ratio of surface PM2.5 to aerosol optical depth (AOD), which is the primary aerosol retrieval made by satellite instruments. While modelling and statistical analyses have improved estimates of PM2.5:AOD, large uncertainties remain in situations of high PM2.5 exposure (such as urban areas and in wildfire-smoke plumes) where the health impacts of PM2.5 may be the greatest. Surface monitoring networks for co-incident PM2.5 and AOD measurements are extremely rare, even in the North America. To provide constraints for the PM2.5:AOD relationship, we have developed a relatively low-cost (application (iOS and Android). Sun photometry is performed across 4 discrete wavelengths that match those reported by the Aerosol Robotic Network (AERONET). Aerosol concentration is reported using both time-integrated filter mass (analyzed in an academic laboratory and reported as a 24-48hr average) and a continuous PM sensor within the instrument. Citizen scientists use the device to report daily AOD and PM2.5 measurements made in their backyards to a central server for data display and download. In this presentation, we provide an overview of (1) AOD and PM2.5 measurement calibration; (2) citizen recruiting and training efforts; and (3) results from our pilot citizen-science measurement campaign.

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

    Directory of Open Access Journals (Sweden)

    C. A. Brock

    2011-03-01

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

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

  6. Atmospheric Polarization Imaging with Variable Aerosols, Clouds, and Surface Albedo

    Science.gov (United States)

    2013-07-01

    values found in this region only during episodes of intense wildfire smoke. Detailed analysis of the aerosols in this smoke plume and their effect...Continuous outdoor operation of an all-sky polarization imager,” Proc. SPIE 7672 (Polarization: Measurement, Analysis , and Remote Sensing IX), 76720A-1-7, 7...Pust, “ Lunar corona in ice wave cloud,” 10th International Meeting on Light and Color in Nature, St. Mary’s College of Maryland, 16-20 June 2010. 2

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

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Manvendra [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aiken, Allison [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Berg, Larry K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Freedman, Andrew [Aerodyne Research, Inc., Billerica, MA (United States); Gorkowski, Kyle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-01

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

  8. Improving Satellite Retrieved Infrared Sea Surface Temperatures in Aerosol-Contaminated Regions

    Science.gov (United States)

    Luo, B.; Minnett, P. J.; Szczodrak, G.; Kilpatrick, K. A.

    2017-12-01

    Infrared satellite observations of sea surface temperature (SST) have become essential for many applications in meteorology, climatology, and oceanography. Applications often require high accuracy SST data: for climate research and monitoring an absolute uncertainty of 0.1K and stability of better than 0.04K per decade are required. Tropospheric aerosol concentrations increase infrared signal attenuation and prevent the retrieval of accurate satellite SST. We compare satellite-derived skin SST with measurements from the Marine-Atmospheric Emitted Radiance Interferometer (M-AERI) deployed on ships during the Aerosols and Ocean Science Expeditions (AEROSE) and with quality-controlled drifter temperatures. After match-up with in-situ SST and filtering of cloud contaminated data, the results indicate that SST retrieved from MODIS (Moderate Resolution Imaging Spectroradiometer) aboard the Terra and Aqua satellites have negative (cool) biases compared to shipboard radiometric measurements. There is also a pronounced negative bias in the Saharan outflow area that can introduce SST errors >1 K at aerosol optical depths > 0.5. In this study, we present a new method to derive night-time Saharan Dust Index (SDI) algorithms based on simulated brightness temperatures at infrared wavelengths of 3.9, 10.8 and 12.0 μm, derived using RTTOV. We derived correction coefficients for Aqua MODIS measurements by regression of the SST errors against the SDI. The biases and standard deviations are reduced by 0.25K and 0.19K after the SDI correction. The goal of this study is to understand better the characteristics and physical mechanisms of aerosol effects on satellite retrieved infrared SST, as well as to derive empirical formulae for improved accuracies in aerosol-contaminated regions.

  9. Portable diffusion battery. It's application to measuring aerosol size characteristics

    International Nuclear Information System (INIS)

    Sinclair, D.

    1972-01-01

    A miniature portable cluster-tube diffusion battery for measurement of the size and size distribution of submicron aerosols (1-100 nm) is described. A series of commercially available Collimated Holes Structures are mounted in sleeves with O-rings so that aerosol penetration can be measured at a number of outlets along the series. The CHS are stainless-steel discs of several different diameters and thicknesses, containing a large number of nearly circular holes. The actual length of the apparatus is about 2 ft but the equivalent length is 3.25 mi. Calculated curves of penetration versus particle size are used to evaluate size distribution and show that the equivalent size frequently reported from one measurement with a rectangular diffusion battery is practically meaningless. The value depends as much on the characteristics and mode of the operation of the diffusion battery as on the aerosol; the longer the battery and the lower the air flow, the greater the equivalent size will appear to be. Graphical plots of the cumulative size distribution of room aerosol and silver aerosol are illustrated for large battery and miniature battery measurements and appear to be in close agreement. Measurements on radon daughters in uranium mines with the miniature batteries show activity median diameters from 0.1 to 0.17 micron, with standard deviations from 2 to 4. Two similar measurements made in the laboratory on room air tagged with about 50 pCi/l radon daughters show activity median diameters of 0.15 and 0.17 micron, with geometric standard deviations of 2.2 and 2.6, respectively

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

    Directory of Open Access Journals (Sweden)

    D. B. Collins

    2014-11-01

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

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

    Science.gov (United States)

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

    2009-04-01

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

  12. Long-term analysis of aerosol optical depth over Northeast Asia using a satellite-based measurement: MI Yonsei Aerosol Retrieval Algorithm (YAER)

    Science.gov (United States)

    Kim, Mijin; Kim, Jhoon; Yoon, Jongmin; Chung, Chu-Yong; Chung, Sung-Rae

    2017-04-01

    In 2010, the Korean geostationary earth orbit (GEO) satellite, the Communication, Ocean, and Meteorological Satellite (COMS), was launched including the Meteorological Imager (MI). The MI measures atmospheric condition over Northeast Asia (NEA) using a single visible channel centered at 0.675 μm and four IR channels at 3.75, 6.75, 10.8, 12.0 μm. The visible measurement can also be utilized for the retrieval of aerosol optical properties (AOPs). Since the GEO satellite measurement has an advantage for continuous monitoring of AOPs, we can analyze the spatiotemporal variation of the aerosol using the MI observations over NEA. Therefore, we developed an algorithm to retrieve aerosol optical depth (AOD) using the visible observation of MI, and named as MI Yonsei Aerosol Retrieval Algorithm (YAER). In this study, we investigated the accuracy of MI YAER AOD by comparing the values with the long-term products of AERONET sun-photometer. The result showed that the MI AODs were significantly overestimated than the AERONET values over bright surface in low AOD case. Because the MI visible channel centered at red color range, contribution of aerosol signal to the measured reflectance is relatively lower than the surface contribution. Therefore, the AOD error in low AOD case over bright surface can be a fundamental limitation of the algorithm. Meanwhile, an assumption of background aerosol optical depth (BAOD) could result in the retrieval uncertainty, also. To estimate the surface reflectance by considering polluted air condition over the NEA, we estimated the BAOD from the MODIS dark target (DT) aerosol products by pixel. The satellite-based AOD retrieval, however, largely depends on the accuracy of the surface reflectance estimation especially in low AOD case, and thus, the BAOD could include the uncertainty in surface reflectance estimation of the satellite-based retrieval. Therefore, we re-estimated the BAOD using the ground-based sun-photometer measurement, and

  13. Aerosol properties and their impacts on surface CCN at the ARM Southern Great Plains site during the 2011 Midlatitude Continental Convective Clouds Experiment

    Science.gov (United States)

    Logan, Timothy; Dong, Xiquan; Xi, Baike

    2018-02-01

    Aerosol particles are of particular importance because of their impacts on cloud development and precipitation processes over land and ocean. Aerosol properties as well as meteorological observations from the Department of Energy Atmospheric Radiation Measurement (ARM) platform situated in the Southern Great Plains (SGP) are utilized in this study to illustrate the dependence of continental cloud condensation nuclei (CCN) number concentration ( N CCN) on aerosol type and transport pathways. ARM-SGP observations from the 2011 Midlatitude Continental Convective Clouds Experiment field campaign are presented in this study and compared with our previous work during the 2009-10 Clouds, Aerosol, and Precipitation in the Marine Boundary Layer field campaign over the current ARM Eastern North Atlantic site. Northerly winds over the SGP reflect clean, continental conditions with aerosol scattering coefficient ( σ sp) values less than 20 Mm-1 and N CCN values less than 100 cm-3. However, southerly winds over the SGP are responsible for the observed moderate to high correlation ( R) among aerosol loading ( σ sp moisture via the Gulf of Mexico, indicating a strong dependence on air mass type. NASA MERRA-2 reanalysis aerosol and chemical data are moderately to highly correlated with surface ARM-SGP data, suggesting that this facility can represent surface aerosol conditions in the SGP, especially during strong aerosol loading events that transport via the Gulf of Mexico. Future long-term investigations will help to understand the seasonal influences of air masses on aerosol, CCN, and cloud properties over land in comparison to over ocean.

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

    Science.gov (United States)

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

    2015-12-01

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

  15. Online high sensitivity measurement system for transuranic aerosols

    International Nuclear Information System (INIS)

    Kordas, J.F.; Phelps, P.L.

    1976-01-01

    A measurement system for transuranic aerosols has been designed that will be able to withstand the corrosive nature of stack effluents and yet have extremely high sensitivity. It will be capable of measuring 1 maximum permissible concentration (MPC) of plutonium or americium in 30 minutes with a fractional standard deviation of less than 0.33. Background resulting from 218 Po is eliminated by alpha energy discrimination and a decay scheme analysis. A microprocessor controls all data acquisition, data reduction, and instrument calibration

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

    Science.gov (United States)

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

    2013-04-01

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

  17. Dry Deposition, Surface Production and Dynamics of Aerosols in the Marine Boundary Layer

    DEFF Research Database (Denmark)

    Fairall, C.W.; Larsen, Søren Ejling

    1984-01-01

    A model of downward aerosol panicle flux characterized by dry deposition velocity, Vd, due to Slinn and Slinn (1980) is generalized to the case of nonzero surface concentration (absorbing surface with a surface source). A more general expression for the flux at some reference height is developed ...... produced as droplets at the surface and ‘continental’ background aerosols brought into the boundary layer at the top by entrainment and gravitational settling. Estimates of Si are provided....

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

    Science.gov (United States)

    Dutcher, Cari; Metcalf, Andrew

    2015-03-01

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

  19. THE INFLUENCE OF AEROSOL GAS-DYNAMIC SUSPENSION CLEANING ON SURFACE OF THE AIRCRAFT PARTS

    Directory of Open Access Journals (Sweden)

    Vitaly D. Hizhko

    2008-02-01

    Full Text Available  The specificity of the surface microgeometry formation under the influence of aerosol gas-dynamic suspension flow was considered. The composition and character of metallic surface layer formation of aircraft parts was investigated. The possibility of surface material composition and properties adjustment changing aerosol gas-dynamic suspension flow parameters was determined. The hypothesis about the possibility of using aerosol gas-dynamic suspension flow to form corrosion-resistant coating on the detail metallic surfaces was set up.

  20. Estimation of atmospheric columnar organic matter (OM) mass concentration from remote sensing measurements of aerosol spectral refractive indices

    Science.gov (United States)

    Zhang, Ying; Li, Zhengqiang; Sun, Yele; Lv, Yang; Xie, Yisong

    2018-04-01

    Aerosols have adverse effects on human health and air quality, changing Earth's energy balance and lead to climate change. The components of aerosol are important because of the different spectral characteristics. Based on the low hygroscopic and high scattering properties of organic matter (OM) in fine modal atmospheric aerosols, we develop an inversion algorithm using remote sensing to obtain aerosol components including black carbon (BC), organic matter (OM), ammonium nitrate-like (AN), dust-like (DU) components and aerosol water content (AW). In the algorithm, the microphysical characteristics (i.e. volume distribution and complex refractive index) of particulates are preliminarily separated to fine and coarse modes, and then aerosol components are retrieved using bimodal parameters. We execute the algorithm using remote sensing measurements of sun-sky radiometer at AERONET site (Beijing RADI) in a period from October of 2014 to January of 2015. The results show a reasonable distribution of aerosol components and a good fit for spectral feature calculations. The mean OM mass concentration in atmospheric column is account for 14.93% of the total and 56.34% of dry and fine-mode aerosol, being a fairly good correlation (R = 0.56) with the in situ observations near the surface layer.

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

    Directory of Open Access Journals (Sweden)

    Angelov Christo

    2016-03-01

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

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

    Science.gov (United States)

    Dreyfus, Matthew A.

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

  3. Design of automatic control and measurement software for radioactive aerosol continuity monitor

    International Nuclear Information System (INIS)

    Mao Yong; Li Aiwu

    1997-01-01

    The radioactive aerosol continuity measurement is very important for the development of nuclear industry, and it is the major method to measure and find out the leakage of radioactive material. Radioactive aerosol continuity monitor is the advanced method for the radioactive aerosol continuity measurement. With the development of nuclear industry and nuclear power station, it is necessary to design and automatic continuity measurement device. Because of this reason, the authors developed the first unit of radioactive aerosol continuity monitor and adopted the ministry appraisal. The design idea and method of automatic control and measurement for radioactive aerosol continuity monitor are discussed

  4. Measurement of complex surfaces

    International Nuclear Information System (INIS)

    Brown, G.M.

    1993-05-01

    Several of the components used in coil fabrication involve complex surfaces and dimensions that are not well suited to measurements using conventional dimensional measuring equipment. Some relatively simple techniques that are in use in the SSCL Magnet Systems Division (MSD) for incoming inspection will be described, with discussion of their suitability for specific applications. Components that are submitted for MSD Quality Assurance (QA) dimensional inspection may be divided into two distinct categories; the first category involves components for which there is an approved drawing and for which all nominal dimensions are known; the second category involves parts for which 'reverse engineering' is required, the part is available but there are no available drawings or dimensions. This second category typically occurs during development of coil end parts and coil turn filler parts where it is necessary to manually shape the part and then measure it to develop the information required to prepare a drawing for the part

  5. Characterization of aerosol photooxidation flow reactors: heterogeneous oxidation, secondary organic aerosol formation and cloud condensation nuclei activity measurements

    Directory of Open Access Journals (Sweden)

    A. T. Lambe

    2011-03-01

    Full Text Available Motivated by the need to develop instrumental techniques for characterizing organic aerosol aging, we report on the performance of the Toronto Photo-Oxidation Tube (TPOT and Potential Aerosol Mass (PAM flow tube reactors under a variety of experimental conditions. The PAM system was designed with lower surface-area-to-volume (SA/V ratio to minimize wall effects; the TPOT reactor was designed to study heterogeneous aerosol chemistry where wall loss can be independently measured. The following studies were performed: (1 transmission efficiency measurements for CO2, SO2, and bis(2-ethylhexyl sebacate (BES particles, (2 H2SO4 yield measurements from the oxidation of SO2, (3 residence time distribution (RTD measurements for CO2, SO2, and BES particles, (4 aerosol mass spectra, O/C and H/C ratios, and cloud condensation nuclei (CCN activity measurements of BES particles exposed to OH radicals, and (5 aerosol mass spectra, O/C and H/C ratios, CCN activity, and yield measurements of secondary organic aerosol (SOA generated from gas-phase OH oxidation of m-xylene and α-pinene. OH exposures ranged from (2.0 ± 1.0 × 1010 to (1.8 ± 0.3 × 1012 molec cm−3 s. Where applicable, data from the flow tube reactors are compared with published results from the Caltech smog chamber. The TPOT yielded narrower RTDs. However, its transmission efficiency for SO2 was lower than that for the PAM. Transmission efficiency for BES and H2SO4 particles was size-dependent and was similar for the two flow tube designs. Oxidized BES particles had similar O/C and H/C ratios and CCN activity at OH exposures greater than 1011 molec cm−3 s, but different CCN activity at lower OH exposures. The O/C ratio, H/C ratio, and yield of m-xylene and α-pinene SOA was strongly affected by reactor design and

  6. Aerosols and surface UV products form Ozone Monitoring Instrument observations: An overview

    NARCIS (Netherlands)

    Torres, O.; Tanskanen, A.; Veihelmann, B.; Ahn, C.; Braak, R.; Bhartia, P.K.; Veefkind, J.P.; Levelt, P.F.

    2007-01-01

    We present an overview of the theoretical and algorithmic aspects of the Ozone Monitoring Instrument (OMI) aerosol and surface UV algorithms. Aerosol properties are derived from two independent algorithms. The nearUV algorithm makes use of OMI observations in the 350-390 nm spectral region to

  7. Physical and chemical characterization of urban winter-time aerosols by mobile measurements in Helsinki, Finland

    Science.gov (United States)

    Pirjola, Liisa; Niemi, Jarkko V.; Saarikoski, Sanna; Aurela, Minna; Enroth, Joonas; Carbone, Samara; Saarnio, Karri; Kuuluvainen, Heino; Kousa, Anu; Rönkkö, Topi; Hillamo, Risto

    2017-06-01

    A two-week measurement campaign by a mobile laboratory van was performed in urban environments in the Helsinki metropolitan area, Finland, in winter 2012, to obtain a comprehensive view on aerosol properties and sources. The abundances and physico-chemical properties of particles varied strongly in time and space, depending on the main sources of aerosols. Four major types of winter aerosol were recognized: 1) clean background aerosol with low particle number (Ntot) and lung deposited surface area (LDSA) concentrations due to marine air flows from the Atlantic Ocean; 2) long-range transported (LRT) pollution aerosol due to air flows from eastern Europe where the particles were characterized by the high contribution of oxygenated organic aerosol (OOA) and inorganic species, particularly sulphate, but low BC contribution, and their size distribution possessed an additional accumulation mode; 3) fresh smoke plumes from residential wood combustion in suburban small houses, these particles were characterized by high biomass burning organic aerosol (BBOA) and black carbon (BC) concentrations; and 4) fresh emissions from traffic while driving on busy streets in the city centre and on the highways during morning rush hours. This aerosol was characterized by high concentration of Ntot, LDSA, small particles in the nucleation mode, as well as high hydrocarbon-like organic aerosol (HOA) and BC concentrations. In general, secondary components (OOA, NO3, NH4, and SO4) dominated the PM1 chemical composition during the LRT episode accounting for 70-80% of the PM1 mass, whereas fresh primary emissions (BC, HOA and BBOA) dominated the local traffic and wood burning emissions. The major individual particle types observed with electron microscopy analysis (TEM/EDX) were mainly related to residential wood combustion (K/S/C-rich, soot, other C-rich particles), traffic (soot, Si/Al-rich, Fe-rich), heavy fuel oil combustion in heat plants or ships (S with V-Ni-Fe), LRT pollutants (S

  8. Modeling the South American regional smoke plume: aerosol optical depth variability and surface shortwave flux perturbation

    Directory of Open Access Journals (Sweden)

    N. E. Rosário

    2013-03-01

    Full Text Available Intra-seasonal variability of smoke aerosol optical depth (AOD and downwelling solar irradiance at the surface during the 2002 biomass burning season in South America was modeled using the Coupled Chemistry-Aerosol-Tracers Transport model with the Brazilian developments on the Regional Atmospheric Modeling System (CCATT-BRAMS. Measurements of total and fine mode fraction (FMF AOD from the AErosol RObotic NETwork (AERONET and solar irradiance at the surface from the Solar Radiation Network (SolRad-NET were used to evaluate model results. In general, the major features associated with AOD evolution over the southern part of the Amazon basin and cerrado ecosystem are captured by the model. The main discrepancies were found for high aerosol loading events. In the northeastern portion of the Amazon basin the model systematically underestimated total AOD, as expected, since smoke contribution is not dominant as it is in the southern portion and emissions other than smoke were not considered in the simulation. Better agreement was obtained comparing the model results with observed FMF AOD, which pointed out the relevance of coarse mode aerosol emission in that region. Likewise, major discrepancies over cerrado during high AOD events were found to be associated with coarse mode aerosol omission in our model. The issue of high aerosol loading events in the southern part of the Amazon was related to difficulties in predicting the smoke AOD field, which was discussed in the context of emissions shortcomings. The Cuiabá cerrado site was the only one where the highest quality AERONET data were unavailable for both total and FMF AOD. Thus, lower quality data were used. Root-mean-square error (RMSE between the model and observed FMF AOD decreased from 0.34 to 0.19 when extreme AOD events (FMF AOD550 nm ≥ 1.0 and Cuiabá were excluded from the analysis. Downward surface solar irradiance comparisons also followed similar trends when extreme AOD were excluded

  9. Tethered balloon-based measurements of meteorological variables and aerosols

    Science.gov (United States)

    Sentell, R. J.; Storey, R. W.; Chang, J. J. C.; Jacobsen, S. J.

    1976-01-01

    Tethered balloon based measurements of the vertical distributions of temperature, humidity, wind speed, and aerosol concentrations were taken over a 4-hour period beginning at sunrise on June 29, 1976, at Wallops Island, Virginia. Twelve consecutive profiles of each variable were obtained from ground to about 500 meters. These measurements were in conjuction with a noise propagation study on remotely arrayed acoustic range (ROMAAR) at Wallops Flight Center. An organized listing of these vertical soundings is presented. The tethered balloon system configuration utilized for these measurements is described.

  10. The impact of changing surface ocean conditions on the dissolution of aerosol iron

    Science.gov (United States)

    Fishwick, Matthew P.; Sedwick, Peter N.; Lohan, Maeve C.; Worsfold, Paul J.; Buck, Kristen N.; Church, Thomas M.; Ussher, Simon J.

    2014-11-01

    The proportion of aerosol iron (Fe) that dissolves in seawater varies greatly and is dependent on aerosol composition and the physicochemical conditions of seawater, which may change depending on location or be altered by global environmental change. Aerosol and surface seawater samples were collected in the Sargasso Sea and used to investigate the impact of these changing conditions on aerosol Fe dissolution in seawater. Our data show that seawater temperature, pH, and oxygen concentration, within the range of current and projected future values, had no significant effect on the dissolution of aerosol Fe. However, the source and composition of aerosols had the most significant effect on the aerosol Fe solubility, with the most anthropogenically influenced samples having the highest fractional solubility (up to 3.2%). The impact of ocean warming and acidification on aerosol Fe dissolution is therefore unlikely to be as important as changes in land usage and fossil fuel combustion. Our experimental results also reveal important changes in the size distribution of soluble aerosol Fe in solution, depending on the chemical conditions of seawater. Under typical conditions, the majority (77-100%) of Fe released from aerosols into ambient seawater existed in the colloidal (0.02-0.4 µm) size fraction. However, in the presence of a sufficient concentration of strong Fe-binding organic ligands (10 nM) most of the aerosol-derived colloidal Fe was converted to soluble Fe (<0.02 µm). This finding highlights the potential importance of organic ligands in retaining aerosol Fe in a biologically available form in the surface ocean.

  11. Acid aerosol measurement method intercomparisons: An outdoor smog chamber study

    International Nuclear Information System (INIS)

    Ellestad, T.G.; Barnes, H.M.; Kamens, R.M.; McDow, S.R.; Sickles, J.E. II; Hodson, L.L.; Waldman, J.M.; Randtke, S.J.; Lane, D.D.; Springston, S.R.; Koutrakis, P.; Thurston, G.D.

    1991-01-01

    A workshop on the measurement of acid aerosols indicated that the sampling methods in use had not been intercompared. Following two laboratory pilot studies, EPA sponsored tests in an outdoor smog chamber with a variety of test aerosols, including sulfuric acid only, photochemical smog with added sulfuric acid, photo-chemical smog with added sulfuric acid and dust, and dust followed by photochemical smog with added sulfuric acid. Two experiments of each type were conducted. Six groups, several of which were active in ambient acid aerosol measurements, participated by operating duplicate samplers for each experiment. Five groups employed a similar method, in which ammonia is removed from the sample stream by diffusion, particles are removed by Teflon filter, and hydrogen ion on the Teflon filter is determined by pH electrode. However, differences existed in the method's implementation among groups in physical design, flow rate, procedures, and analysis. The sixth group's method did not use a diffusion denuder for ammonia and had several other important differences. Besides hydrogen ion, seven other species were reported by most of the groups, including particle phase sulfate, ammonium, and nitrate, and gas phase sulfur dioxide, ammonia, nitric acid, and nitrous acid. Results of the inter-comparison will be presented

  12. Retrievals of Aerosol Microphysics from Simulations of Spaceborne Multiwavelength Lidar Measurements

    Science.gov (United States)

    Whiteman, David N.; Perez-Ramírez, Daniel; Veselovskii, Igor; Colarco, Peter; Buchard, Virginie

    2017-01-01

    In support of the Aerosol, Clouds, Ecosystems mission, simulations of a spaceborne multiwavelength lidar are performed based on global model simulations of the atmosphere along a satellite orbit track. The yield for aerosol microphysical inversions is quantified and comparisons are made between the aerosol microphysics inherent in the global model and those inverted from both the model's optical data and the simulated three backscatter and two extinction lidar measurements, which are based on the model's optical data. We find that yield can be significantly increased if inversions based on a reduced optical dataset of three backscatter and one extinction are acceptable. In general, retrieval performance is better for cases where the aerosol fine mode dominates although a lack of sensitivity to particles with sizes less than 0.1 microns is found. Lack of sensitivity to coarse mode cases is also found, in agreement with earlier studies. Surface area is generally the most robustly retrieved quantity. The work here points toward the need for ancillary data to aid in the constraints of the lidar inversions and also for joint inversions involving lidar and polarimeter measurements.

  13. Measurements of organic gases during aerosol formation events in the boreal forest atmosphere during QUEST

    Directory of Open Access Journals (Sweden)

    K. Sellegri

    2005-01-01

    Full Text Available Biogenic VOCs are important in the growth and possibly also in the early stages of formation of atmospheric aerosol particles. In this work, we present 10 min-time resolution measurements of organic trace gases at Hyytiälä, Finland during March 2002. The measurements were part of the project QUEST (Quantification of Aerosol Nucleation in the European Boundary Layer and took place during a two-week period when nucleation events occurred with various intensities nearly every day. Using a ground-based Chemical Ionization Mass Spectrometer (CIMS instrument, the following trace gases were detected: acetone, TMA, DMA, mass 68amu (candidate=isoprene, monoterpenes, methyl vinyl ketone (MVK and methacrolein (MaCR and monoterpene oxidation products (MTOP. For all of them except for the amines, we present daily variations during different classes of nucleation events, and non-event days. BVOC oxidation products (MVK, MaCR and MTOP show a higher ratio to the CS on event days compared to non-event days, indicating that their abundance relative to the surface of aerosol available is higher on nucleation days. Moreover, BVOC oxidation products are found to show significant correlations with the condensational sink (CS on nucleation event days, which indicates that they are representative of less volatile organic compounds that contribute to the growth of the nucleated particles and generally secondary organic aerosol formation. Behaviors of BVOC on event and non event days are compared to the behavior of CO.

  14. HSRL-2 aerosol optical measurements and microphysical retrievals vs. airborne in situ measurements during DISCOVER-AQ 2013: an intercomparison study

    Directory of Open Access Journals (Sweden)

    P. Sawamura

    2017-06-01

    Full Text Available We present a detailed evaluation of remotely sensed aerosol microphysical properties obtained from an advanced, multi-wavelength high-spectral-resolution lidar (HSRL-2 during the 2013 NASA DISCOVER-AQ field campaign. Vertically resolved retrievals of fine-mode aerosol number, surface-area, and volume concentration as well as aerosol effective radius are compared to 108 collocated, airborne in situ measurement profiles in the wintertime San Joaquin Valley, California, and in summertime Houston, Texas. An algorithm for relating the dry in situ aerosol properties to those obtained by the HSRL at ambient relative humidity is discussed. We show that the HSRL-2 retrievals of ambient fine-mode aerosol surface-area and volume concentrations agree with the in situ measurements to within 25 and 10 %, respectively, once hygroscopic growth adjustments have been applied to the dry in situ data. Despite this excellent agreement for the microphysical properties, extinction and backscatter coefficients at ambient relative humidity derived from the in situ aerosol measurements using Mie theory are consistently smaller than those measured by the HSRL, with average differences of 31 ± 5 % and 53 ± 11 % for California and Texas, respectively. This low bias in the in situ estimates is attributed to the presence of coarse-mode aerosol that are detected by HSRL-2 but that are too large to be well sampled by the in situ instrumentation. Since the retrieval of aerosol volume is most relevant to current regulatory efforts targeting fine particle mass (PM2. 5, these findings highlight the advantages of an advanced 3β + 2α HSRL for constraining the vertical distribution of the aerosol volume or mass loading relevant for air quality.

  15. Sea spray aerosol fluxes in the Baltic Sea region: Comparison of the WAM model with measurements

    Science.gov (United States)

    Markuszewski, Piotr; Kosecki, Szymon; Petelski, Tomasz

    2017-08-01

    Sea spray aerosol flux is an important element of sub-regional climate modeling. The majority of works related to this topic concentrate on open ocean research rather than on smaller, inland seas, e.g., the Baltic Sea. The Baltic Sea is one of the largest brackish inland seas by area, where major inflows of oceanic waters are rare. Furthermore, surface waves in the Baltic Sea have a relatively shorter lifespan in comparison with oceanic waves. Therefore, emission of sea spray aerosol may differ greatly from what is known from oceanic research and should be investigated. This article presents a comparison of sea spray aerosol measurements carried out on-board the s/y Oceania research ship with data calculated in accordance to the WAM model. The measurements were conducted in the southern region of the Baltic Sea during four scientific cruises. The gradient method was used to determinate aerosol fluxes. The fluxes were calculated for particles of diameter in range of 0.5-47 μm. The correlation between wind speed measured and simulated has a good agreement (correlation in range of 0.8). The comparison encompasses three different sea spray generation models. First, function proposed by Massel (2006) which is based only on wave parameters, such as significant wave height and peak frequency. Second, Callaghan (2013) which is based on Gong (2003) model (wind speed relation), and a thorough experimental analysis of whitecaps. Third, Petelski et al. (2014) which is based on in-situ gradient measurements with the function dependent on wind speed. The two first models which based on whitecaps analysis are insufficient. Moreover, the research shows strong relation between aerosol emission and wind speed history.

  16. Nano-TiO{sub 2} coatings on aluminum surfaces by aerosol flame synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Liberini, Mariacira; De Falco, Gianluigi; Scherillo, Fabio; Astarita, Antonello [Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli Federico II, Napoli 80125 (Italy); Commodo, Mario; Minutolo, Patrizia [Istituto di Ricerche sulla Combustione, CNR, Napoli 80125 (Italy); D' Anna, Andrea, E-mail: anddanna@unina.it [Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli Federico II, Napoli 80125 (Italy); Squillace, Antonino [Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli Federico II, Napoli 80125 (Italy)

    2016-06-30

    Aluminum alloys are widely used in the aeronautic industry for their high mechanical properties; however, because they are very sensitive to corrosion, surface treatments are often required. TiO{sub 2} has excellent resistance to oxidation and it is often used to improve the corrosion resistance of aluminum surfaces. Several coating procedures have been proposed over the years, which are in some cases expensive in terms of production time and amount of deposited material. Moreover, they can damage aluminum alloys if thermal treatments are required. In this paper, a one-step method for the coating of aluminum surfaces with titania nanoparticles is presented. Narrowly sized, TiO{sub 2} nanoparticles are synthesized by flame aerosol and directly deposited by thermophoresis onto cold plates of aluminum AA2024. Submicron coatings of different thicknesses are obtained from two flame synthesis conditions by varying the total deposition time. A fuel-lean synthesis condition was used to produce 3.5 nm pure anatase nanoparticles, while a mixture of rutile and anatase nanoparticles having 22 nm diameter — rutile being the predominant phase —, was synthesized in a fuel-rich condition. Scanning electron microscopy is used to characterize morphology of titania films, while coating thickness is measured by confocal microscopy measurements. Electrochemical impedance spectroscopy is used to evaluate corrosion resistance of coated aluminum substrates. Results show an improvement of the electrochemical behavior of titania coated surfaces as compared to pristine aluminum surfaces. The best results are obtained by covering the substrates with 3.5 nm anatase-phase nanoparticles and with lower deposition times, that assure a uniform surface coating. - Highlights: • Nanosized TiO{sub 2} particles produced by aerosol flame synthesis • Coatings of aluminum substrates with TiO{sub 2} nanoparticles by thermophoretic deposition in flames • Thickness measurement by confocal microscopy

  17. Nano-TiO_2 coatings on aluminum surfaces by aerosol flame synthesis

    International Nuclear Information System (INIS)

    Liberini, Mariacira; De Falco, Gianluigi; Scherillo, Fabio; Astarita, Antonello; Commodo, Mario; Minutolo, Patrizia; D'Anna, Andrea; Squillace, Antonino

    2016-01-01

    Aluminum alloys are widely used in the aeronautic industry for their high mechanical properties; however, because they are very sensitive to corrosion, surface treatments are often required. TiO_2 has excellent resistance to oxidation and it is often used to improve the corrosion resistance of aluminum surfaces. Several coating procedures have been proposed over the years, which are in some cases expensive in terms of production time and amount of deposited material. Moreover, they can damage aluminum alloys if thermal treatments are required. In this paper, a one-step method for the coating of aluminum surfaces with titania nanoparticles is presented. Narrowly sized, TiO_2 nanoparticles are synthesized by flame aerosol and directly deposited by thermophoresis onto cold plates of aluminum AA2024. Submicron coatings of different thicknesses are obtained from two flame synthesis conditions by varying the total deposition time. A fuel-lean synthesis condition was used to produce 3.5 nm pure anatase nanoparticles, while a mixture of rutile and anatase nanoparticles having 22 nm diameter — rutile being the predominant phase —, was synthesized in a fuel-rich condition. Scanning electron microscopy is used to characterize morphology of titania films, while coating thickness is measured by confocal microscopy measurements. Electrochemical impedance spectroscopy is used to evaluate corrosion resistance of coated aluminum substrates. Results show an improvement of the electrochemical behavior of titania coated surfaces as compared to pristine aluminum surfaces. The best results are obtained by covering the substrates with 3.5 nm anatase-phase nanoparticles and with lower deposition times, that assure a uniform surface coating. - Highlights: • Nanosized TiO_2 particles produced by aerosol flame synthesis • Coatings of aluminum substrates with TiO_2 nanoparticles by thermophoretic deposition in flames • Thickness measurement by confocal microscopy • Improvement of

  18. Retrievals and uncertainty analysis of aerosol single scattering albedo from MFRSR measurements

    International Nuclear Information System (INIS)

    Yin, Bangsheng; Min, Qilong; Joseph, Everette

    2015-01-01

    Aerosol single scattering albedo (SSA) can be retrieved from the ratio of diffuse horizontal and direct normal fluxes measured from multifilter rotating shadowband radiometer (MFRSR). In this study, the measurement channels at 415 nm and 870 nm are selected for aerosol optical depth (AOD) and Angstrom coefficient retrievals, and the measurements at 415 nm are used for aerosol SSA retrievals with the constraint of retrieved Angstrom coefficient. We extensively assessed various issues impacting on the accuracy of SSA retrieval from measurements to input parameters and assumptions. For cloud-free days with mean aerosol loading of 0.13–0.60, our sensitivity study indicated that: (1) 1% calibration uncertainty can result in 0.8–3.7% changes in retrieved SSA; (2) without considering the cosine respond correction and/or forward scattering correction will result in underestimation of 1.1–3.3% and/or 0.73% in retrieved SSA; (3) an overestimation of 0.1 in asymmetry factor can result in an underestimation of 2.54–3.4% in retrieved SSA; (4) for small aerosol loading (e.g., 0.13), the uncertainty associated with the choice of Rayleigh optical depth value can result in non-negligible change in retrieved SSA (e.g., 0.015); (5) an uncertainty of 0.05 for surface albedo can result in changes of 1.49–5.4% in retrieved SSA. We applied the retrieval algorithm to the MFRSR measurements at the Atmospheric Radiation Measurements (ARM) Southern Great Plains (SGP) site. The retrieved results of AOD, Angstrom coefficient, and SSA are basically consistent with other independent measurements from co-located instruments at the site. - Highlights: • Aerosol SSA is derived from MFRSR measured diffuse to direct normal irradiance ratio. • We extensively assessed various issues impacting on the accuracy of SSA retrieval. • The issues are mainly from measurements and model input parameters and assumptions. • We applied the retrieval algorithm to the MFRSR measurements at ARM SGP

  19. Modelling of Aerosol Chemistry and Transport over Europe and Comparison with Measurements

    NARCIS (Netherlands)

    Jeuken, A.; Veefkind, J.P.; Metzger, S.; Denter, F.; Velthoven, P.

    1999-01-01

    Because of the short lifetime of aerosols (days-weeks), the radiative forcing associated with aerosols varies strongly spatially and temporally (see van Dorland et al., poster) Current measurement networks of sulfate and other aerosol species are unable to provide a representative picture of the

  20. Measurements of mesospheric ice aerosols using radars and rockets

    Energy Technology Data Exchange (ETDEWEB)

    Strelnikova, Irina; Li, Qiang; Strelnikov, Boris; Rapp, Markus [Leibniz Institute of Atmospheric Physics, Kuehlungsborn (Germany)

    2010-07-01

    Polar summer mesopause is the coldest region of Earth's atmosphere with temperatures as low as minus 130 C. In this extreme environment ice aerosol layers have appeared. Larger aerosols can be seen from the ground as clouds known as NLC (Noctilucent clouds). Ice aerosols from sub-visible range give rise to the phenomena known as Polar Mesosphere Sommer Echo (PMSE). For efficient scattering, electron number density must be structured at the radar half wavelength (Bragg condition). The general requirement to allow for the observation of structures at VHF and higher frequencies is that the dust size (and charge number) must be large enough to extend the convective-diffusive subrange of the energy spectrum of electrons (by reducing their diffusivity) to the wavelength which is shorter than the Bragg-scale of the probing radar. In this paper we present main results of ice particles measurements inside the PMSE layers obtained from in situ rocket soundings and newly developed radar techniques.

  1. Measurements of phoretic velocities of aerosol particles in microgravity conditions

    Science.gov (United States)

    Prodi, F.; Santachiara, G.; Travaini, S.; Vedernikov, A.; Dubois, F.; Minetti, C.; Legros, J. C.

    2006-11-01

    Measurements of thermo- and diffusio-phoretic velocities of aerosol particles (carnauba wax, paraffin and sodium chloride) were performed in microgravity conditions (Drop Tower facility, in Bremen, and Parabolic Flights, in Bordeaux). In the case of thermophoresis, a temperature gradient was obtained by heating the upper plate of the cell, while the lower one was maintained at environmental temperature. For diffusiophoresis, the water vapour gradient was obtained with sintered plates imbued with a water solution of MgCl 2 and distilled water, at the top and at the bottom of the cell, respectively. Aerosol particles were observed through a digital holographic velocimeter, a device allowing the determination of 3-D coordinates of particles from the observed volume. Particle trajectories and consequently particle velocities were reconstructed through the analysis of the sequence of particle positions. The experimental values of reduced thermophoretic velocities are between the theoretical values of Yamamoto and Ishihara [Yamamoto, K., Ishihara, Y., 1988. Thermophoresis of a spherical particle in a rarefied gas of a transition regime. Phys. Fluids. 31, 3618-3624] and Talbot et al. [Talbot, L., Cheng, R.K., Schefer, R.W., Willis, D.R., 1980. Thermophoresis of particles in a heated boundary layer. J. Fluid Mech. 101, 737-758], and do not show a clear dependence on the thermal conductivity of the aerosol. The existence of negative thermophoresis is not confirmed in our experiments. Concerning diffusiophoretic experiments, the results obtained show a small increase of reduced diffusiophoretic velocity with the Knudsen number.

  2. Ground-based SMART-COMMIT Measurements for Studying Aerosol and Cloud Properties

    Science.gov (United States)

    Tsay, Si-Chee

    2008-01-01

    From radiometric principles, it is expected that the retrieved properties of extensive aerosols and clouds from reflected/emitted measurements by satellite (and/or aircraft) should be consistent with those retrieved from transmitted/emitted radiance observed at the surface. Although space-borne remote sensing observations cover large spatial domain, they are often plagued by contamination of surface signatures. Thus, ground-based in-situ and remote-sensing measurements, where signals come directly from atmospheric constituents, the sun, and/or the Earth-atmosphere interactions, provide additional information content for comparisons that confirm quantitatively the usefulness of the integrated surface, aircraft, and satellite data sets. The development and deployment of SMARTCOMMIT (Surface-sensing Measurements for Atmospheric Radiative Transfer - Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile facilities are aimed for the optimal utilization of collocated ground-based observations as constraints to yield higher fidelity satellite retrievals and to determine any sampling bias due to target conditions. To quantify the energetics of the surface-atmosphere system and the atmospheric processes, SMART-COMMIT instruments fall into three categories: flux radiometer, radiance sensor and in-situ probe. In this paper, we will demonstrate the capability of SMART-COMMIT in recent field campaigns (e.g., CRYSTAL-FACE, UAE 2, BASEASIA, NAMMA) that were designed and executed to study the compelling variability in temporal scale of both anthropogenic and natural aerosols (e.g., biomass-burning smoke, airborne dust) and cirrus clouds. We envision robust approaches in which well-collocated ground-based measurements and space-borne observations will greatly advance our knowledge of extensive aerosols and clouds.

  3. Estimation of surface-level PM2.5 concentration using aerosol optical thickness through aerosol type analysis method

    Science.gov (United States)

    Chen, Qi-Xiang; Yuan, Yuan; Huang, Xing; Jiang, Yan-Qiu; Tan, He-Ping

    2017-06-01

    Surface-level particulate matter is closely related to column aerosol optical thickness (AOT). Previous researches have successfully used column AOT and different meteorological parameters to estimate surface-level PM concentration. In this study, the performance of a selected linear model that estimates surface-level PM2.5 concentration was evaluated following the aerosol type analysis method (ATAM) for the first time. We utilized 443 daily average data for Xuzhou, Jiangsu province, collected using Aerosol Robotic Network (AERONET) during the period October 2013 to April 2016. Several parameters including atmospheric boundary layer height (BLH), relative humidity (RH), and effective radius of the aerosol size distribution (Ref) were used to assess the relationship between the column AOT and PM2.5 concentration. By including the BLH, ambient RH, and effective radius, the correlation (R2) increased from 0.084 to 0.250 at Xuzhou, and with the use of ATAM, the correlation increased further to 0.335. To compare the results, 450 daily average data for Beijing, pertaining to the same period, were utilized. The study found that model correlations improved by varying degrees in different seasons and at different sites following ATAM. The average urban industry (UI) aerosol ratios at Xuzhou and Beijing were 0.792 and 0.451, respectively, demonstrating poorer air conditions at Xuzhou. PM2.5 estimation at Xuzhou showed lower correlation (R2 = 0.335) compared to Beijing (R2 = 0.407), and the increase of R2 at Xuzhou and Beijing site following use of ATAM were 33.8% and 12.4%, respectively.

  4. A sea surface reflectance model for (AATSR, and application to aerosol retrievals

    Directory of Open Access Journals (Sweden)

    A. M. Sayer

    2010-07-01

    Full Text Available A model of the sea surface bidirectional reflectance distribution function (BRDF is presented for the visible and near-IR channels (over the spectral range 550 nm to 1.6 μm of the dual-viewing Along-Track Scanning Radiometers (ATSRs. The intended application is as part of the Oxford-RAL Aerosols and Clouds (ORAC retrieval scheme. The model accounts for contributions to the observed reflectance from whitecaps, sun-glint and underlight. Uncertainties in the parametrisations used in the BRDF model are propagated through into the forward model and retrieved state. The new BRDF model offers improved coverage over previous methods, as retrievals are possible into the sun-glint region, through the ATSR dual-viewing system. The new model has been applied in the ORAC aerosol retrieval algorithm to process Advanced ATSR (AATSR data from September 2004 over the south-eastern Pacific. The assumed error budget is shown to be generally appropriate, meaning the retrieved states are consistent with the measurements and a priori assumptions. The resulting field of aerosol optical depth (AOD is compared with colocated MODIS-Terra observations, AERONET observations at Tahiti, and cruises over the oceanic region. MODIS and AATSR show similar spatial distributions of AOD, although MODIS reports values which are larger and more variable. It is suggested that assumptions in the MODIS aerosol retrieval algorithm may lead to a positive bias in MODIS AOD of order 0.01 at 550 nm over ocean regions where the wind speed is high.

  5. Light scattering measurements with Titan's aerosols analogues produced by dusty plasma

    Science.gov (United States)

    Hadamcik, E.; Renard, J.-B.; Szopa, C.; Cernogora, G.; Levasseur-Regourd, A. C.

    The Titan s atmosphere contains solid aerosols produced by the photochemistry of nitrogen and methane These aerosols are at the origin of the characteristic brown yellow colour of Titan During the descent of the Huygens probe the 14 th January 2005 optical measurements of the Titan s haze and Titan s surface have been done In order to explain the obtained results laboratory simulations are necessary We produce analogues of the Titan s aerosols in a RF capacitively coupled low-pressure plasma in a N 2 --CH 4 mixture representative of the Titan s atmosphere Szopa et al 2006 Szopa et al this conference The morphology of the produced solid aerosols is observed by SEM analyses They are quasi spherical and their mean size is function of the plasma conditions Moreover their colour changes from yellow to brown as a function of CH 4 ratio in the plasma In order to have information on the optical properties of the produced aerosols measurements have been performed with the PROGRA2 experiment Renard et al 2002 The PROGRA2 experiment measures the phase dependence of the linear polarization of the light scattered by dust particles for two wavelengths 543 5 nm and 632 8 nm The particles are lifted either in microgravity in the CNES ESA dedicated airplane or by an air-draught in ground-based conditions The aim of this work is to build a database for further modelling of the optical properties of Titan s in connection with the Huygens data These particles have also an astrophysical interest as organic compounds Hadamcik et

  6. Interception and retention of aerosols by vegetation in relation to their surface cuticular characteristics

    International Nuclear Information System (INIS)

    Watterson, John David

    1989-01-01

    Material produced from nuclear incidents, which is deposited onto plant surfaces, can be lost in a variety of ways including the removal of the deposited material in association with the leaf surface layers. This 'field loss' has previously been shown to occur under dry conditions by the transfer of deposited material from one plant, spatially seperated from another, 'and it has been postulated that the vector for this transfer is the epicuticular wax on the leaf surface. There is clear evidence that air pollutants, including SO 2 , alter the morphology of epicuticular wax. Therefore, it is postulated that the presence of air pollutants will affect the rate of field loss of deposited material. The work examined whether the rate of field loss of deposited material was modified by the level of leaf epicuticular wax, and examined the potential interaction of field loss with air pollutants. Two preliminary experiments were performed by depositing the activable rare earth element Dysprosium (Dy) onto peas, and determining the level of transfer onto 'clean' plants. A low level of transfer was suggested. A stirred box was designed and manufactured for the deposition of a soluble 5μm Cs aerosol onto peas with 'waxy' and 'waxless' surfaces. After a growth period of one month in the absence of rain, substantial field loss was shown (ca. 50%). This loss was independent of the wax levels. Subsequently, an aerosol of Cs labelled silica was deposited over a canopy of 'waxy' peas in a wind tunnel under defined aerodynamic conditions. After a similar growth period, substantial field loss was shown to occur in the absence of rain. A deposition velocity for the aerosol was calculated, and flow measurements over the canopy were performed. The epicuticular wax of barley, grown in an SO 2 field fumigation system, was periodically examined for damage. Material grown under background and elevated SO 2 conditions was transported from the site to the wind tunnel. A deposition of labelled

  7. Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically resolved aerosol fluxes

    Directory of Open Access Journals (Sweden)

    D. K. Farmer

    2011-06-01

    Full Text Available Although laboratory studies show that biogenic volatile organic compounds (VOCs yield substantial secondary organic aerosol (SOA, production of biogenic SOA as indicated by upward fluxes has not been conclusively observed over forests. Further, while aerosols are known to deposit to surfaces, few techniques exist to provide chemically-resolved particle deposition fluxes. To better constrain aerosol sources and sinks, we have developed a new technique to directly measure fluxes of chemically-resolved submicron aerosols using the high-resolution time-of-flight aerosol mass spectrometer (HR-AMS in a new, fast eddy covariance mode. This approach takes advantage of the instrument's ability to quantitatively identify both organic and inorganic components, including ammonium, sulphate and nitrate, at a temporal resolution of several Hz. The new approach has been successfully deployed over a temperate ponderosa pine plantation in California during the BEARPEX-2007 campaign, providing both total and chemically resolved non-refractory (NR PM1 fluxes. Average deposition velocities for total NR-PM1 aerosol at noon were 2.05 ± 0.04 mm s−1. Using a high resolution measurement of the NH2+ and NH3+ fragments, we demonstrate the first eddy covariance flux measurements of particulate ammonium, which show a noon-time deposition velocity of 1.9 ± 0.7 mm s−1 and are dominated by deposition of ammonium sulphate.

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

    Science.gov (United States)

    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. Surface aerosol and rehabilitation properties of ground-level atmosphere in the mountains of the North Caucasus

    Science.gov (United States)

    Reps, Valentina; Efimenko, Natalia; Povolotskaya, Nina; Abramtsova, Anna; Ischenko, Dmitriy; Senik, Irina; Slepikh, Victor

    2017-04-01

    The rehabilitative properties (RP) of ground-level atmosphere (GA) of Russian resorts are considered as natural healing resources and received state legal protection [1]. Due to global urbanization the chemical composition and particle size distribution of the surface aerosol are changing rapidly. However, the influence of surface aerosol on the RP of GA has been insufficiently studied. At the resort region of the North Caucasus complex monitoring (aerosol, trace gases NOx, CO, O3, CH4; periodically - heavy metals) is performed at two high levels (860 masl - a park zone of a large mountain resort, 2070 masl - alpine grassland, the net station). The results of the measurements are used in programs of bioclimatic, landscape and medical monitoring to specify the influence of aerosol on rehabilitation properties of the environment and human adaptative reserves. The aerosol particles of size range 500-1000 nm are used as a marker of the pathogenic effect of aerosol [2]. In the conditions of regional urbanization and complicated mountain atmospheric circulation the influence of aerosol on RP of GA and the variability of heart rhythm with the volunteers at different heights were investigated. At the height of 860 masl (urbanized resort) there have been noticed aerosol variations in the range of 0,04-0,35 particles/cm3 (slightly aerosol polluted), in mountain conditions - background pollution aerosol level. The difference of bioclimatic conditions at the specified high-rise levels has been referred to the category of contrasts. The natural aero ionization ∑(N+)+(N-) varied from 960 ion/cm3 to 1460 ion/cm3 in the resort park (860 m); from 1295 ion/cm3 to 4850 ion/cm3 on the Alpine meadow (2070 m); from 1128 ion/cm3 to 3420 ion/cm3 - on the tested site near the edge of the pinewood (1720 m). In the group of volunteers the trip from low-hill terrain zone (860 m) to the lower zone of highlands (2070 m) caused the activation of neuro and humoral regulation, vegetative and

  10. The measurement of the radioactive aerosol diameter by position sensitive detectors, 3

    International Nuclear Information System (INIS)

    Murakami, Hiroyuki; Nakamoto, Atsushi; Kanamori, Masashi; Seki, Akio.

    1981-10-01

    The measurement of the diameter of radioactive aerosol, in particular plutonium aerosol, is very important for the internal dose estimation. Determination of the diameter of radioactive aerosol is performed by using the position sensitive detectors. Position sensitive semiconductor detectors and Scintillation detectors with IIT tube are used as the position sensitive detector. The filter paper with the radioactive aerosols is contacted to the PSD which is connected to the data processor so that the diameter of the aerosol is calculated from the measured radioactivity. (author)

  11. Unipolar charging of nanoparticles by the Surface-discharge Microplasma Aerosol Charger (SMAC)

    International Nuclear Information System (INIS)

    Kwon, Soon-Bark; Sakurai, Hiromu; Seto, Takafumi

    2007-01-01

    In this paper, we report the development of a novel unipolar charger for nanoparticles, a system that achieves low particle loss and high charging efficiency without the use of sheath air. The efficient unipolar charging of the system is realized mainly by the surface-discharge microplasma unit, a device previously applied with good success to the neutralization or charging of submicron particles [Kwon et al., 2005, Aerosol Sci. Technol., 39, 987-1001; 2006, J. Aerosol Sci., 37, 483-499]. The unipolar charger generates unipolar ions using the surface discharge of a single electrode with a DC pulse supply. This marks an advance from our previous method of generating bipolar ions with the use of dual electrodes in earlier studies. We evaluated the efficiency of the penetration (or loss) and charging of nanoparticles in the size range of 3-15 nm, then compared the charging efficiencies measured with those predicted by diffusion charging theory. More than 90% of inlet nanoparticles penetrated the charger (less than 10% of the particle were lost) without the use of sheath air. Other chargers have only realized this high penetration efficiency by relying on sheath air flow. Moreover, the measured charging efficiencies agreed well with those predicted by diffusion charging theory and were somewhat higher and more size-dependent than the charging efficiencies of other nanoparticle chargers

  12. Aerosol counterflow two-jets unit for continuous measurement of the soluble fraction of atmospheric aerosols.

    Science.gov (United States)

    Mikuska, Pavel; Vecera, Zbynek

    2005-09-01

    A new type of aerosol collector employing a liquid at laboratory temperature for continuous sampling of atmospheric particles is described. The collector operates on the principle of a Venturi scrubber. Sampled air flows at high linear velocity through two Venturi nozzles "atomizing" the liquid to form two jets of a polydisperse aerosol of fine droplets situated against each other. Counterflow jets of droplets collide, and within this process, the aerosol particles are captured into dispersed liquid. Under optimum conditions (air flow rate of 5 L/min and water flow rate of 2 mL/min), aerosol particles down to 0.3 microm in diameter are quantitatively collected in the collector into deionized water while the collection efficiency of smaller particles decreases. There is very little loss of fine aerosol within the aerosol counterflow two-jets unit (ACTJU). Coupling of the aerosol collector with an annular diffusion denuder located upstream of the collector ensures an artifact-free sampling of atmospheric aerosols. Operation of the ACTJU in combination with on-line detection devices allows in situ automated analysis of water-soluble aerosol species (e.g., NO2-, NO3-)with high time resolution (as high as 1 s). Under the optimum conditions, the limit of detection for particulate nitrite and nitrate is 28 and 77 ng/m(3), respectively. The instrument is sufficiently rugged for its application at routine monitoring of aerosol composition in the real time.

  13. Aerosol Properties and Their Impacts on Surface CCN at the ARM Southern Great Plains Site during the 2011 Midlatitude Continental Convective Clouds Experiment

    Institute of Scientific and Technical Information of China (English)

    Timothy LOGAN; Xiquan DONG; Baike XI

    2018-01-01

    Aerosol particles are of particular importance because of their impacts on cloud development and precipitation processes over land and ocean.Aerosol properties as well as meteorological observations from the Department of Energy Atmospheric Radiation Measurement (ARM) platform situated in the Southern Great Plains (SGP) are utilized in this study to illustrate the dependence of continental cloud condensation nuclei (CCN) number concentration (NCCN) on aerosol type and transport pathways.ARM-SGP observations from the 2011 Midlatitude Continental Convective Clouds Experiment field campaign are presented in this study and compared with our previous work during the 2009-10 Clouds,Aerosol,and Precipitation in the Marine Boundary Layer field campaign over the current ARM Eastern North Atlantic site.Northerly winds over the SGP reflect clean,continental conditions with aerosol scattering coefficient (σsp) values less than 20 Mm-1 and NCCN values less than 100 cm-3.However,southerly winds over the SGP are responsible for the observed moderate to high correlation (R)among aerosol loading (σsp > 60 Mm-1) and NCCN,carbonaceous chemical species (biomass burning smoke),and precipitable water vapor.This suggests a common transport mechanism for smoke aerosols and moisture via the Gulf of Mexico,indicating a strong dependence on air mass type.NASA MERRA-2 reanalysis aerosol and chemical data are moderately to highly correlated with surface ARM-SGP data,suggesting that this facility can represent surface aerosol conditions in the SGP,especially during strong aerosol loading events that transport via the Gulf of Mexico.Future long-term investigations will help to understand the seasonal influences of air masses on aerosol,CCN,and cloud properties over land in comparison to over ocean.

  14. Measurement-based climatology of aerosol direct radiative effect, its sensitivities, and uncertainties from a background southeast US site

    Science.gov (United States)

    Sherman, James P.; McComiskey, Allison

    2018-03-01

    Aerosol optical properties measured at Appalachian State University's co-located NASA AERONET and NOAA ESRL aerosol network monitoring sites over a nearly four-year period (June 2012-Feb 2016) are used, along with satellite-based surface reflectance measurements, to study the seasonal variability of diurnally averaged clear sky aerosol direct radiative effect (DRE) and radiative efficiency (RE) at the top-of-atmosphere (TOA) and at the surface. Aerosol chemistry and loading at the Appalachian State site are likely representative of the background southeast US (SE US), home to high summertime aerosol loading and one of only a few regions not to have warmed during the 20th century. This study is the first multi-year ground truth DRE study in the SE US, using aerosol network data products that are often used to validate satellite-based aerosol retrievals. The study is also the first in the SE US to quantify DRE uncertainties and sensitivities to aerosol optical properties and surface reflectance, including their seasonal dependence.Median DRE for the study period is -2.9 W m-2 at the TOA and -6.1 W m-2 at the surface. Monthly median and monthly mean DRE at the TOA (surface) are -1 to -2 W m-2 (-2 to -3 W m-2) during winter months and -5 to -6 W m-2 (-10 W m-2) during summer months. The DRE cycles follow the annual cycle of aerosol optical depth (AOD), which is 9 to 10 times larger in summer than in winter. Aerosol RE is anti-correlated with DRE, with winter values 1.5 to 2 times more negative than summer values. Due to the large seasonal dependence of aerosol DRE and RE, we quantify the sensitivity of DRE to aerosol optical properties and surface reflectance, using a calendar day representative of each season (21 December for winter; 21 March for spring, 21 June for summer, and 21 September for fall). We use these sensitivities along with measurement uncertainties of aerosol optical properties and surface reflectance to calculate DRE uncertainties. We also estimate

  15. An aerosol optical depth climatology for NOAA's national surface radiation budget network (SURFRAD)

    Science.gov (United States)

    Augustine, John A.; Hodges, Gary B.; Dutton, Ellsworth G.; Michalsky, Joseph J.; Cornwall, Christopher R.

    2008-06-01

    A series of algorithms developed to process spectral solar measurements for aerosol optical depth (AOD) for the National Oceanic and Atmospheric Administration's (NOAA) national surface radiation budget network (SURFRAD) is summarized, and decadal results are presented. AOD is a measure of the extinction of the Sun's beam due to aerosols. Daily files of AOD for five spectral measurements in the visible and near-infrared have been produced for 1997-2006. Comparisons of SURFRAD daily AOD averages to NASA's Aerosol Robotic Network product at two of the stations were generally good. An AOD climatology for each SURFRAD station is presented as an annual time series of composite monthly means that represents a typical intra-annual AOD variation. Results are similar to previous U.S. climatologies in that the highest AOD magnitude and greatest variability occur in summer, the lowest AOD levels are in winter, and geographically, the highest-magnitude AOD is in the eastern United States. Springtime Asian dust intrusions show up as a secondary maximum at the western stations. A time series of nationwide annual means shows that 500-nm AOD has decreased over the United States by about 0.02 AOD units over the 10-year period. However, this decline is not statistically significant nor geographically consistent within the country. The eastern U.S. stations and westernmost station at Desert Rock, Nevada, show decreasing AOD, whereas the other two western stations show an increase that is attributed to an upsurge in wildfire activity in the last half of the decade.

  16. Measurement of phase function of aerosol at different altitudes by CCD Lidar

    Science.gov (United States)

    Sun, Peiyu; Yuan, Ke'e.; Yang, Jie; Hu, Shunxing

    2018-02-01

    The aerosols near the ground are closely related to human health and climate change, the study on which has important significance. As we all know, the aerosol is inhomogeneous at different altitudes, of which the phase function is also different. In order to simplify the retrieval algorithm, it is usually assumed that the aerosol is uniform at different altitudes, which will bring measurement error. In this work, an experimental approach is demonstrated to measure the scattering phase function of atmospheric aerosol particles at different heights by CCD lidar system, which could solve the problem of the traditional CCD lidar system in assumption of phase function. The phase functions obtained by the new experimental approach are used to retrieve the aerosol extinction coefficient profiles. By comparison of the aerosol extinction coefficient retrieved by Mie-scattering aerosol lidar and CCD lidar at night, the reliability of new experimental approach is verified.

  17. Enhancement of the aerosol direct radiative effect by semi-volatile aerosol components: airborne measurements in North-Western Europe

    Directory of Open Access Journals (Sweden)

    W. T. Morgan

    2010-09-01

    Full Text Available A case study of atmospheric aerosol measurements exploring the impact of the vertical distribution of aerosol chemical composition upon the radiative budget in North-Western Europe is presented. Sub-micron aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS on both an airborne platform and a ground-based site at Cabauw in the Netherlands. The examined period in May 2008 was characterised by enhanced pollution loadings in North-Western Europe and was dominated by ammonium nitrate and Organic Matter (OM. Both ammonium nitrate and OM were observed to increase with altitude in the atmospheric boundary layer. This is primarily attributed to partitioning of semi-volatile gas phase species to the particle phase at reduced temperature and enhanced relative humidity. Increased ammonium nitrate concentrations in particular were found to strongly increase the ambient scattering potential of the aerosol burden, which was a consequence of the large amount of associated water as well as the enhanced mass. During particularly polluted conditions, increases in aerosol optical depth of 50–100% were estimated to occur due to the observed increase in secondary aerosol mass and associated water uptake. Furthermore, the single scattering albedo was also shown to increase with height in the boundary layer. These enhancements combined to increase the negative direct aerosol radiative forcing by close to a factor of two at the median percentile level. Such increases have major ramifications for regional climate predictions as semi-volatile components are often not included in aerosol models.

    The results presented here provide an ideal opportunity to test regional and global representations of both the aerosol vertical distribution and subsequent impacts in North-Western Europe. North-Western Europe can be viewed as an analogue for the possible future air quality over other polluted regions of the Northern Hemisphere, where

  18. The Effect of Non-Lambertian Surface Reflectance on Aerosol Radiative Forcing

    Energy Technology Data Exchange (ETDEWEB)

    Ricchiazzi, P.; O' Hirok, W.; Gautier, C.

    2005-03-18

    Surface reflectance is an important factor in determining the strength of aerosol radiative forcing. Previous studies of radiative forcing assumed that the reflected surface radiance is isotropic and does not depend on incident illumination angle. This Lambertian reflection model is not a very good descriptor of reflectance from real land and ocean surfaces. In this study we present computational results for the seasonal average of short and long wave aerosol radiative forcing at the top of the atmosphere and at the surface. The effect of the Lambertian assumption is found through comparison with calculations using a more detailed bi-direction reflectance distribution function (BRDF).

  19. Diffusivity measurements of volatile organics in levitated viscous aerosol particles

    Directory of Open Access Journals (Sweden)

    S. Bastelberger

    2017-07-01

    Full Text Available Field measurements indicating that atmospheric secondary organic aerosol (SOA particles can be present in a highly viscous, glassy state have spurred numerous studies addressing low diffusivities of water in glassy aerosols. The focus of these studies is on kinetic limitations of hygroscopic growth and the plasticizing effect of water. In contrast, much less is known about diffusion limitations of organic molecules and oxidants in viscous matrices. These may affect atmospheric chemistry and gas–particle partitioning of complex mixtures with constituents of different volatility. In this study, we quantify the diffusivity of a volatile organic in a viscous matrix. Evaporation of single particles generated from an aqueous solution of sucrose and small amounts of volatile tetraethylene glycol (PEG-4 is investigated in an electrodynamic balance at controlled relative humidity (RH and temperature. The evaporative loss of PEG-4 as determined by Mie resonance spectroscopy is used in conjunction with a radially resolved diffusion model to retrieve translational diffusion coefficients of PEG-4. Comparison of the experimentally derived diffusivities with viscosity estimates for the ternary system reveals a breakdown of the Stokes–Einstein relationship, which has often been invoked to infer diffusivity from viscosity. The evaporation of PEG-4 shows pronounced RH and temperature dependencies and is severely depressed for RH ≲ 30 %, corresponding to diffusivities < 10−14 cm2 s−1 at temperatures < 15 °C. The temperature dependence is strong, suggesting a diffusion activation energy of about 300 kJ mol−1. We conclude that atmospheric volatile organic compounds can be subject to severe diffusion limitations in viscous organic aerosol particles. This may enable an important long-range transport mechanism for organic material, including pollutant molecules such as polycyclic aromatic hydrocarbons (PAHs.

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

    Science.gov (United States)

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

    2016-10-01

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

  1. Crystal nucleation initiated by transient ion-surface interactions at aerosol interfaces.

    Science.gov (United States)

    Davis, Ryan D; Tolbert, Margaret A

    2017-07-01

    Particle collisions are a common occurrence in the atmosphere, but no empirical observations exist to fully predict the potential effects of these collisions on air quality and climate projections. The current consensus of heterogeneous crystal nucleation pathways relevant to the atmosphere dictates that collisions with amorphous particles have no effect on the crystallization relative humidity (RH) of aqueous inorganic aerosols because there is no stabilizing ion-surface interaction to facilitate the formation of crystal nuclei. In contrast to this view of heterogeneous nucleation, we report laboratory observations demonstrating that collisions with hydrophobic amorphous organic aerosols induced crystallization of aqueous inorganic microdroplets at high RH, the effect of which was correlated with destabilizing water-mediated ion-specific surface interactions. These same organic aerosols did not induce crystallization once internally mixed in the droplet, pointing toward a previously unconsidered transient ion-specific crystal nucleation pathway that can promote aerosol crystallization via particle collisions.

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

    Directory of Open Access Journals (Sweden)

    Shu Zhifeng

    2016-01-01

    Full Text Available Visibility is one of the most important parameters for meteorological observation and numerical weather prediction (NWP.It is also an important factor in everyday life, mainly for surface and air traffic especially in the Aeronautical Meteorology. The visibility decides the taking off and landing of aircraft. If the airport visibility is lower than requirement for aircraft taking off stipulated by International Civil Aviation Administration, then the aircraft must be parked at the airport. So the accurate measurement of visibility is very important. Nowadays, many devices can be measured the visibility or meteorological optical range (MOR such as Scatterometers, Transmissometers and visibility lidar. But there is not effective way to verify the accuracy of these devices expect the artificial visual method. We have developed a visibility testing system that can be calibration and verification these devices. The system consists of laser transmitter, optical chopper, phase-locking amplifier, the moving optic receiving system, signal detection and data acquisition system, atmospheric aerosol simulation chamber. All of them were placed in the atmosphere aerosol simulation chamber with uniform aerosol concentration. The Continuous wave laser, wavelength 550nm, has been transmitted into the collimation system then the laser beam expanded into 40mm diameter for compressing the laser divergence angle before modulated by optical chopper. The expanding beam transmitting in the atmosphere aerosol cabin received by the optic receiving system moving in the 50m length precision guide with 100mm optical aperture. The data of laser signal has been acquired by phase-locking amplifier every 5 meter range. So the 10 data points can be detected in the 50 meters guide once. The slope of the fitting curve can be obtained by linear fitting these data using the least square method. The laser extinction coefficient was calculated from the slope using the Koschmieder

  3. Generation and characterization of biological aerosols for laser measurements

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-01

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

  4. Effects of stratospheric aerosol surface processes on the LLNL two-dimensional zonally averaged model

    International Nuclear Information System (INIS)

    Connell, P.S.; Kinnison, D.E.; Wuebbles, D.J.; Burley, J.D.; Johnston, H.S.

    1992-01-01

    We have investigated the effects of incorporating representations of heterogeneous chemical processes associated with stratospheric sulfuric acid aerosol into the LLNL two-dimensional, zonally averaged, model of the troposphere and stratosphere. Using distributions of aerosol surface area and volume density derived from SAGE 11 satellite observations, we were primarily interested in changes in partitioning within the Cl- and N- families in the lower stratosphere, compared to a model including only gas phase photochemical reactions

  5. Improved Tandem Measurement Techniques for Aerosol Particle Analysis

    Science.gov (United States)

    Rawat, Vivek Kumar

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

  6. Modeling Dry Deposition of Aerosol Particles on Rough Surfaces

    Czech Academy of Sciences Publication Activity Database

    Hussein, T.; Smolík, Jiří; Kerminen, V.-M.; Kulmala, M.

    2012-01-01

    Roč. 46, č. 1 (2012), s. 44-59 ISSN 0278-6826 Institutional research plan: CEZ:AV0Z40720504 Keywords : aerosol particles * dry deposition * transport Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.780, year: 2012

  7. Surface-Sensitive and Bulk Studies on the Complexation and Photosensitized Degradation of Catechol by Iron(III) as a Model for Multicomponent Aerosol Systems

    Science.gov (United States)

    Al-abadleh, H. A.; Tofan-Lazar, J.; Situm, A.; Ruffolo, J.; Slikboer, S.

    2013-12-01

    Surface water plays a crucial role in facilitating or inhibiting surface reactions in atmospheric aerosols. Little is known about the role of surface water in the complexation of organic molecules to transition metals in multicomponent aerosol systems. We will show results from real time diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments for the in situ complexation of catechol to Fe(III) and its photosensitized degradation under dry and humid conditions. Catechol was chosen as a simple model for humic-like substances (HULIS) in aerosols and aged polyaromatic hydrocarbons (PAH). It has also been detected in secondary organic aerosols (SOA) formed from the reaction of hydroxyl radicals with benzene. Given the importance of the iron content in aerosols and its biogeochemistry, our studies were conducted using FeCl3. For comparison, these surface-sensitive studies were complemented with bulk aqueous ATR-FTIR, UV-vis, and HPLC measurements for structural, quantitative and qualitative information about complexes in the bulk, and potential degradation products. The implications of our studies on understanding interfacial and condensed phase chemistry relevant to multicomponent aerosols, water thin islands on buildings, and ocean surfaces containing transition metals will be discussed.

  8. Diffusivity measurements of volatile organics in levitated viscous aerosol particles

    Science.gov (United States)

    Bastelberger, Sandra; Krieger, Ulrich K.; Luo, Beiping; Peter, Thomas

    2017-07-01

    Field measurements indicating that atmospheric secondary organic aerosol (SOA) particles can be present in a highly viscous, glassy state have spurred numerous studies addressing low diffusivities of water in glassy aerosols. The focus of these studies is on kinetic limitations of hygroscopic growth and the plasticizing effect of water. In contrast, much less is known about diffusion limitations of organic molecules and oxidants in viscous matrices. These may affect atmospheric chemistry and gas-particle partitioning of complex mixtures with constituents of different volatility. In this study, we quantify the diffusivity of a volatile organic in a viscous matrix. Evaporation of single particles generated from an aqueous solution of sucrose and small amounts of volatile tetraethylene glycol (PEG-4) is investigated in an electrodynamic balance at controlled relative humidity (RH) and temperature. The evaporative loss of PEG-4 as determined by Mie resonance spectroscopy is used in conjunction with a radially resolved diffusion model to retrieve translational diffusion coefficients of PEG-4. Comparison of the experimentally derived diffusivities with viscosity estimates for the ternary system reveals a breakdown of the Stokes-Einstein relationship, which has often been invoked to infer diffusivity from viscosity. The evaporation of PEG-4 shows pronounced RH and temperature dependencies and is severely depressed for RH ≲ 30 %, corresponding to diffusivities pollutant molecules such as polycyclic aromatic hydrocarbons (PAHs).

  9. Dry deposition of submicron atmospheric aerosol over water surfaces in motion

    International Nuclear Information System (INIS)

    Nevenick, Calec

    2013-01-01

    conditions (central wind speed: 1, 2, 4, 5, 7.5 and 9.5 m/s), current (co - current and counter-current, water flow velocity: 0, 6 and 12 cm/s ), ambient (temperature and relative humidity of the air and water temperature), the liquid surface deformations (measured significant wave height) and size distribution of aerosols released. The modeling part was to adapt the model to resistance. Slinn and Slinn (1980). This model is based on the assumption of conservation of vertical flow in the boundary layer. This one is divided into two layers: a very thin deposition layer near the surface which is water-saturated and a transfer layer located above. The transfer layer provides the particle deposition layer by turbulent diffusion and sedimentation. In the deposition layer the particles are deposited under the effect of several mechanisms such as Brownian diffusion, sedimentation, impaction and phoretic mechanisms. The main adjustments made by this work have been to take specific account of the different classes of particle size distribution, the spectrum variation as a function of hygroscopicity, and mechanisms of aggregation. It is integrated mechanisms of diffusiophoresis and thermophoresis, respectively produced by the evaporation of water and the temperature gradient at the air-water interface. To account for hygroscopic uranine aerosols, the deposition rates are analyzed in terms of humidity and rescaled by the friction velocity. In all cases, the deposition rates rescaled by the friction velocity range from 10 -3 to a wind speed of 1 m/s to 10 -5 - 10 -4 for wind speeds above 5 m/s. It is shown that the changing speed rescaled is inversely proportional to the wind velocity when the water surface is smooth (between 1 and 5 m/s ) and becomes proportional to the deformation when the surface becomes significant (over 5 m/s ). Although the results do not clearly identify the effect of the current on the deposition velocity, the modeling shows that turbulent diffusion is dominant

  10. Dry deposition of submicron atmospheric aerosol over water surfaces in motion

    International Nuclear Information System (INIS)

    Calec, Nevenick

    2013-01-01

    conditions (central wind speed: 1, 2, 4, 5, 7.5 and 9.5 m/s), current (co-current and counter-current, water flow velocity: 0, 6 and 12 cm/s), ambient (temperature and relative humidity of the air and water temperature), the liquid surface deformations (measured significant wave height) and size distribution of aerosols released. The modeling part was to adapt the model to resistance. Slinn and Slinn (1980). This model is based on the assumption of conservation of vertical flow in the boundary layer. This one is divided into two layers: a very thin deposition layer near the surface which is water-saturated and a transfer layer located above. The transfer layer provides the particle deposition layer by turbulent diffusion and sedimentation. In the deposition layer the particles are deposited under the effect of several mechanisms such as Brownian diffusion, sedimentation, impaction and phoretic mechanisms. The main adjustments made by this work have been to take specific account of the different classes of particle size distribution, the spectrum variation as a function of hygroscopicity, and mechanisms of aggregation. It is integrated mechanisms of diffusiophoresis and thermophoresis, respectively produced by the evaporation of water and the temperature gradient at the air-water interface. To account for hygroscopic uranine aerosols, the deposition rates are analyzed in terms of humidity and rescaled by the friction velocity. In all cases, the deposition rates rescaled by the friction velocity range from 10 -3 to a wind speed of 1 m/s to 10 -5 - 10 -4 for wind speeds above 5 m/s. It is shown that the changing speed rescaled is inversely proportional to the wind velocity when the water surface is smooth (between 1 and 5 m/s ) and becomes proportional to the deformation when the surface becomes significant (over 5 m/s ). Although the results do not clearly identify the effect of the current on the deposition velocity, the modeling shows that turbulent diffusion is dominant in

  11. Vertical profiles of aerosol optical properties and the solar heating rate estimated by combining sky radiometer and lidar measurements

    Science.gov (United States)

    Kudo, Rei; Nishizawa, Tomoaki; Aoyagi, Toshinori

    2016-07-01

    The SKYLIDAR algorithm was developed to estimate vertical profiles of aerosol optical properties from sky radiometer (SKYNET) and lidar (AD-Net) measurements. The solar heating rate was also estimated from the SKYLIDAR retrievals. The algorithm consists of two retrieval steps: (1) columnar properties are retrieved from the sky radiometer measurements and the vertically mean depolarization ratio obtained from the lidar measurements and (2) vertical profiles are retrieved from the lidar measurements and the results of the first step. The derived parameters are the vertical profiles of the size distribution, refractive index (real and imaginary parts), extinction coefficient, single-scattering albedo, and asymmetry factor. Sensitivity tests were conducted by applying the SKYLIDAR algorithm to the simulated sky radiometer and lidar data for vertical profiles of three different aerosols, continental average, transported dust, and pollution aerosols. The vertical profiles of the size distribution, extinction coefficient, and asymmetry factor were well estimated in all cases. The vertical profiles of the refractive index and single-scattering albedo of transported dust, but not those of transported pollution aerosol, were well estimated. To demonstrate the performance and validity of the SKYLIDAR algorithm, we applied the SKYLIDAR algorithm to the actual measurements at Tsukuba, Japan. The detailed vertical structures of the aerosol optical properties and solar heating rate of transported dust and smoke were investigated. Examination of the relationship between the solar heating rate and the aerosol optical properties showed that the vertical profile of the asymmetry factor played an important role in creating vertical variation in the solar heating rate. We then compared the columnar optical properties retrieved with the SKYLIDAR algorithm to those produced with the more established scheme SKYRAD.PACK, and the surface solar irradiance calculated from the SKYLIDAR

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

    Science.gov (United States)

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

    2005-07-01

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

  13. Impact of varying lidar measurement and data processing techniques in evaluating cirrus cloud and aerosol direct radiative effects

    Science.gov (United States)

    Lolli, Simone; Madonna, Fabio; Rosoldi, Marco; Campbell, James R.; Welton, Ellsworth J.; Lewis, Jasper R.; Gu, Yu; Pappalardo, Gelsomina

    2018-03-01

    In the past 2 decades, ground-based lidar networks have drastically increased in scope and relevance, thanks primarily to the advent of lidar observations from space and their need for validation. Lidar observations of aerosol and cloud geometrical, optical and microphysical atmospheric properties are subsequently used to evaluate their direct radiative effects on climate. However, the retrievals are strongly dependent on the lidar instrument measurement technique and subsequent data processing methodologies. In this paper, we evaluate the discrepancies between the use of Raman and elastic lidar measurement techniques and corresponding data processing methods for two aerosol layers in the free troposphere and for two cirrus clouds with different optical depths. Results show that the different lidar techniques are responsible for discrepancies in the model-derived direct radiative effects for biomass burning (0.05 W m-2 at surface and 0.007 W m-2 at top of the atmosphere) and dust aerosol layers (0.7 W m-2 at surface and 0.85 W m-2 at top of the atmosphere). Data processing is further responsible for discrepancies in both thin (0.55 W m-2 at surface and 2.7 W m-2 at top of the atmosphere) and opaque (7.7 W m-2 at surface and 11.8 W m-2 at top of the atmosphere) cirrus clouds. Direct radiative effect discrepancies can be attributed to the larger variability of the lidar ratio for aerosols (20-150 sr) than for clouds (20-35 sr). For this reason, the influence of the applied lidar technique plays a more fundamental role in aerosol monitoring because the lidar ratio must be retrieved with relatively high accuracy. In contrast, for cirrus clouds, with the lidar ratio being much less variable, the data processing is critical because smoothing it modifies the aerosol and cloud vertically resolved extinction profile that is used as input to compute direct radiative effect calculations.

  14. Size measurement of radioactive aerosol particles in intense radiation fields using wire screens and imaging plates

    Energy Technology Data Exchange (ETDEWEB)

    Oki, Yuichi; Tanaka, Toru; Takamiya, Koichi; Ishi, Yoshihiro; UesugI, Tomonori; Kuriyama, Yasutoshi; Sakamoto, Masaaki; Ohtsuki, Tsutomu [Kyoto University Research Reactor Institute, Osaka (Japan); Nitta, Shinnosuke [Graduate School of Engineering, Kyoto University, Kyoto (Japan); Osada, Naoyuki [Advanced Science Research Center, Okayama University, Okayama (Japan)

    2016-09-15

    Very fine radiation-induced aerosol particles are produced in intense radiation fields, such as high-intensity accelerator rooms and containment vessels such as those in the Fukushima Daiichi nuclear power plant (FDNPP). Size measurement of the aerosol particles is very important for understanding the behavior of radioactive aerosols released in the FDNPP accident and radiation safety in high-energy accelerators. A combined technique using wire screens and imaging plates was developed for size measurement of fine radioactive aerosol particles smaller than 100 nm in diameter. This technique was applied to the radiation field of a proton accelerator room, in which radioactive atoms produced in air during machine operation are incorporated into radiation-induced aerosol particles. The size of 11C-bearing aerosol particles was analyzed using the wire screen technique in distinction from other positron emitters in combination with a radioactive decay analysis. The size distribution for 11C-bearing aerosol particles was found to be ca. 70 μm in geometric mean diameter. The size was similar to that for 7Be-bearing particles obtained by a Ge detector measurement, and was slightly larger than the number-based size distribution measured with a scanning mobility particle sizer. The particle size measuring method using wire screens and imaging plates was successfully applied to the fine aerosol particles produced in an intense radiation field of a proton accelerator. This technique is applicable to size measurement of radioactive aerosol particles produced in the intense radiation fields of radiation facilities.

  15. The theory of the interaction of atmospheric aerosol with underlying surface

    International Nuclear Information System (INIS)

    Buikov, M.V.

    1993-01-01

    The interaction of wind with underlying surfaces through resuspension makes a great contribution to the total amount of atmospheric aerosols. The dry deposition process results in cleaning of the atmosphere and contamination of near-surface air layers of soil and vegetation. This paper examines the theory leading to an exact solution of the problem of turbulent transportation of pollution taking into account resuspension and dry-deposition. This may be useful for the interpretation of observational data and for the improvement of calculation methods to describe aerosol exchange at surfaces in air. (author)

  16. Aerosol optical properties and direct radiative forcing based on measurements from the China Aerosol Remote Sensing Network (CARSNET) in eastern China

    Science.gov (United States)

    Che, Huizheng; Qi, Bing; Zhao, Hujia; Xia, Xiangao; Eck, Thomas F.; Goloub, Philippe; Dubovik, Oleg; Estelles, Victor; Cuevas-Agulló, Emilio; Blarel, Luc; Wu, Yunfei; Zhu, Jun; Du, Rongguang; Wang, Yaqiang; Wang, Hong; Gui, Ke; Yu, Jie; Zheng, Yu; Sun, Tianze; Chen, Quanliang; Shi, Guangyu; Zhang, Xiaoye

    2018-01-01

    Aerosol pollution in eastern China is an unfortunate consequence of the region's rapid economic and industrial growth. Here, sun photometer measurements from seven sites in the Yangtze River Delta (YRD) from 2011 to 2015 were used to characterize the climatology of aerosol microphysical and optical properties, calculate direct aerosol radiative forcing (DARF) and classify the aerosols based on size and absorption. Bimodal size distributions were found throughout the year, but larger volumes and effective radii of fine-mode particles occurred in June and September due to hygroscopic growth and/or cloud processing. Increases in the fine-mode particles in June and September caused AOD440 nm > 1.00 at most sites, and annual mean AOD440 nm values of 0.71-0.76 were found at the urban sites and 0.68 at the rural site. Unlike northern China, the AOD440 nm was lower in July and August (˜ 0.40-0.60) than in January and February (0.71-0.89) due to particle dispersion associated with subtropical anticyclones in summer. Low volumes and large bandwidths of both fine-mode and coarse-mode aerosol size distributions occurred in July and August because of biomass burning. Single-scattering albedos at 440 nm (SSA440 nm) from 0.91 to 0.94 indicated particles with relatively strong to moderate absorption. Strongly absorbing particles from biomass burning with a significant SSA wavelength dependence were found in July and August at most sites, while coarse particles in March to May were mineral dust. Absorbing aerosols were distributed more or less homogeneously throughout the region with absorption aerosol optical depths at 440 nm ˜ 0.04-0.06, but inter-site differences in the absorption Angström exponent indicate a degree of spatial heterogeneity in particle composition. The annual mean DARF was -93 ± 44 to -79 ± 39 W m-2 at the Earth's surface and ˜ -40 W m-2 at the top of the atmosphere (for the solar zenith angle range of 50 to 80°) under cloud-free conditions. The fine mode

  17. Elevated aerosol layers modify the O2–O2 absorption measured by ground-based MAX-DOAS

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Ivan; Berg, Larry K.; Ferrare, Richard A.; Hair, Johnathan W.; Hostetler, Chris A.; Volkamer, Rainer

    2016-06-01

    The oxygen collisional complex (O2-O2, or O4) is a greenhouse gas, and a calibration trace gas used to infer aerosol and cloud properties by Differential Optical Absorption Spectroscopy (DOAS). Recent reports suggest the need for an O4 correction factor (CFO4) when comparing simulated and measured O4 differential slant column densities (dSCD) by passive DOAS. We investigate the sensitivity of O4 dSCD simulations at ultraviolet (360 nm) and visible (477 nm) wavelengths towards separately measured aerosol extinction profiles. Measurements were conducted by the University of Colorado 2D-MAX-DOAS instrument and NASA’s multispectral High Spectral Resolution Lidar (HSRL-2) during the Two Column Aerosol Project (TCAP) at Cape Cod, MA in July 2012. During two case study days with (1) high aerosol load (17 July, AOD ~ 0.35 at 477 nm), and (2) near molecular scattering conditions (22 July, AOD < 0.10 at 477 nm) the measured and calculated O4 dSCDs agreed within 6.4±0.4% (360 nm) and 4.7±0.6% (477 nm) if the HSRL-2 profiles were used as input to the calculations. However, if in the calculations the aerosol is confined to the surface layer (while keeping AOD constant) we find 0.53aerosol layers, unless accounted for, can cause negative bias in the simulated O4 dSCDs that can explain CFO4. The air density and aerosol profile aloft needs to be taken into account when interpreting the O4 from ground-based MAX-DOAS. Opportunities to identify and better characterize these layers are also discussed.

  18. Measurement of surface roughness

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    This document is used in connection with two 3 hours laboratory exercises that are part of the course GEOMETRICAL METROLOGY AND MACHINE TESTING. The laboratories include a demonstration of the function of roughness measuring instruments plus a series of exercises illustrating roughness measurement...

  19. UAV measurements of aerosol properties at the Cyprus institute

    Science.gov (United States)

    Neitola, Kimmo; Sciare, Jean; Keleshis, Christos; Pikridas, Michael; Argyrides, Marios; Vouterakos, Panagiotis; Antoniou, Panyiota; Apostolou, Apostolos; Savvides, Constantinos; Vrekoussis, Mihalis; Mihalopoulos, Nikos; Biskos, George; Gao, Ru-Shan; Murphy, Daniel; Schrod, Jann; Weber, Daniel; Bingemer, Heinz; Mocnik, Grisa

    2017-04-01

    Unmanned Aerial Vehicles (UAVs) provide a cost-effective and easy-to-use method to document the vertical profiles of aerosol particles and their physical and optical properties, within and above the boundary layer. These observations combined with satellite and ground data together can provide important information and model constrains regarding the impact of aerosols on the air quality and regional climate. Cyprus is a unique place to observe long-range transported pollution and dust originating from different areas (Europe, Africa, Turkey, and Middle East) and perform such aerosol profiling. The USRL team at the Cyprus Institute has recently started weekly routine flights with a newly developed UAV fleet to build a unique dataset of vertical profile observations. Instrumentation on the UAVs includes miniature Scanning Aerosol Sun Photometer (miniSASP, Murphy et al., 2015), Printed Optical Particle Spectrometer (POPS, Gao et al., 2016), Ice nuclei sampler (IN) and Dual Wavelength absorption Prototype (DWP) together with the measured meteorological parameters (P, T and RH). The UAV fleet is still expanding, as well as the instrumentation, and preliminary test flights have led to very promising results. The UAV ascend up to approximately the middle of the boundary layer, defined by LIDAR measurements at Limassol, where the UAV will fly on one altitude for several minutes ensuring stable data collection. After flying on one altitude, the UAV will continue ascending above the boundary layer, where another level flight will take place for data gathering, before descending for safe landing. The miniSASP measures the sun irradiance and sky radiance at four wavelengths (460, 550, 670 and 680nm) by doing continuous almucantar scans every 30 s. The instrument installation compensates for the pitch and roll of the UAV with 4 Hz frequency. For this reason, the flights are designed to maintain level flight conditions, to ensure proper data acquisition, and to obtain data from

  20. Retrieve Aerosol Concentration Based On Surface Model and Distribution of Concentration of PM2.5 ——A Case Study of Beijing

    Science.gov (United States)

    Cui, H.

    2017-12-01

    As China's economy continues to grow, urbanization continues to advance, along with growth in all areas to pollutant emissions in the air industry, air quality also continued to deteriorate. Aerosol concentrations as a measure of air quality of the most important part of are more and more people's attention. Traditional monitoring stations measuring aerosol concentration method is accurate, but time-consuming and can't be done simultaneously measure a large area, can only rely on data from several monitoring sites to predict the concentration of the panorama. Remote Sensing Technology retrieves aerosol concentrations being by virtue of their efficient, fast advantages gradually into sight. In this paper, by the method of surface model to start with the physical processes of atmospheric transport, innovative aerosol concentration coefficient proposed to replace the traditional aerosol concentrations, pushed to a set of retrieval of aerosol concentration coefficient method, enabling fast and efficient Get accurate air pollution target area. At the same paper also monitoring data for PM2.5 in Beijing were analyzed from different angles, from the perspective of the data summarized in Beijing PM2.5 concentration of time, space, geographical distribution and concentration of PM2.5 and explored the relationship between aerosol concentration coefficient and concentration of PM2.5.

  1. Adsorption and revaporisation studies of thin iodine oxide and CsI aerosol deposits from containment surface materials in LWRs

    Energy Technology Data Exchange (ETDEWEB)

    Tietze, S.; Foreman, M.; Ekberg, C. [Chalmers Univ. of Technology, Goeteborg (Sweden); Kaerkelae, T.; Auvinen, A.; Tapper, U.; Jokiniemi, J. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2013-07-15

    During a severe nuclear accident released fission and radiolysis products can react with each other to form new species which might contribute to the volatile source term. Iodine will be released from UO2 fuel mainly in form as CsI aerosol particles and elemental iodine. Elemental iodine can react in gaseous phase with ozone to form solid iodine oxide aerosol particles (IOx). Within the AIAS-2 (Adsorption of Iodine Aerosols on Surfaces) project the interactions of IOx and CsI aerosols with common containment surface materials was investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS. Non-radioactive and {sup 131}I labelled aerosols were produced from a KI solution and ozone with a new facility designed and built at VTT Technical Research Centre of Finland. CsI aerosols were produced from a CsI solution with the same facility. A monolayer of the aerosols was deposited on the surfaces. The deposits were analysed with microscopic and spectroscopic measurement techniques to identify the chemical form of the deposits on the surfaces to identify if a chemical conversion on the different surface materials had occured. The revaporisation behaviour of the deposited aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 with a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The decomposition effect of the radiolysis product carbon monoxide was tested on IOx aerosols deposited on a glass fibre filter. Iodine oxide particles were produced at 50 deg. C, 100 deg. C and 120 deg. C and deposited on filter samples in order to study the chemical

  2. Adsorption and revaporisation studies of thin iodine oxide and CsI aerosol deposits from containment surface materials in LWRs

    International Nuclear Information System (INIS)

    Tietze, S.; Foreman, M.; Ekberg, C.; Kaerkelae, T.; Auvinen, A.; Tapper, U.; Jokiniemi, J.

    2013-07-01

    During a severe nuclear accident released fission and radiolysis products can react with each other to form new species which might contribute to the volatile source term. Iodine will be released from UO2 fuel mainly in form as CsI aerosol particles and elemental iodine. Elemental iodine can react in gaseous phase with ozone to form solid iodine oxide aerosol particles (IOx). Within the AIAS-2 (Adsorption of Iodine Aerosols on Surfaces) project the interactions of IOx and CsI aerosols with common containment surface materials was investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS. Non-radioactive and 131 I labelled aerosols were produced from a KI solution and ozone with a new facility designed and built at VTT Technical Research Centre of Finland. CsI aerosols were produced from a CsI solution with the same facility. A monolayer of the aerosols was deposited on the surfaces. The deposits were analysed with microscopic and spectroscopic measurement techniques to identify the chemical form of the deposits on the surfaces to identify if a chemical conversion on the different surface materials had occured. The revaporisation behaviour of the deposited aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 with a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The decomposition effect of the radiolysis product carbon monoxide was tested on IOx aerosols deposited on a glass fibre filter. Iodine oxide particles were produced at 50 deg. C, 100 deg. C and 120 deg. C and deposited on filter samples in order to study the chemical speciation of

  3. Aerosol indirect effects on the nighttime Arctic Ocean surface from thin, predominantly liquid clouds

    Directory of Open Access Journals (Sweden)

    L. M. Zamora

    2017-06-01

    Full Text Available Aerosol indirect effects have potentially large impacts on the Arctic Ocean surface energy budget, but model estimates of regional-scale aerosol indirect effects are highly uncertain and poorly validated by observations. Here we demonstrate a new way to quantitatively estimate aerosol indirect effects on a regional scale from remote sensing observations. In this study, we focus on nighttime, optically thin, predominantly liquid clouds. The method is based on differences in cloud physical and microphysical characteristics in carefully selected clean, average, and aerosol-impacted conditions. The cloud subset of focus covers just ∼ 5 % of cloudy Arctic Ocean regions, warming the Arctic Ocean surface by ∼ 1–1.4 W m−2 regionally during polar night. However, within this cloud subset, aerosol and cloud conditions can be determined with high confidence using CALIPSO and CloudSat data and model output. This cloud subset is generally susceptible to aerosols, with a polar nighttime estimated maximum regionally integrated indirect cooling effect of ∼ −0.11 W m−2 at the Arctic sea ice surface (∼ 8 % of the clean background cloud effect, excluding cloud fraction changes. Aerosol presence is related to reduced precipitation, cloud thickness, and radar reflectivity, and in some cases, an increased likelihood of cloud presence in the liquid phase. These observations are inconsistent with a glaciation indirect effect and are consistent with either a deactivation effect or less-efficient secondary ice formation related to smaller liquid cloud droplets. However, this cloud subset shows large differences in surface and meteorological forcing in shallow and higher-altitude clouds and between sea ice and open-ocean regions. For example, optically thin, predominantly liquid clouds are much more likely to overlay another cloud over the open ocean, which may reduce aerosol indirect effects on the surface. Also, shallow clouds over

  4. Long Term Stratospheric Aerosol Lidar Measurements in Kyushu

    Science.gov (United States)

    Fujiwara, Motowo

    1992-01-01

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

  5. SAFARI 2000 Atmospheric Aerosol Measurements, Hand-held Hazemeters, Zambia

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: In conjunction with the AERONET (AErosol RObotic NETwork) participation in SAFARI 2000, the USDA Forest Service deployed handheld hazemeters in western...

  6. Aerosol measurement techniques and accuracy in the CSTF

    International Nuclear Information System (INIS)

    McCormack, J.D.; Hilliard, R. K.

    1979-11-01

    The Containment Systems Test Facility (CSTF) provides the capability of performing large-scale aerosol behavior experiments at a scale factor of approximately 0.5 in height for a typical reactor containment building. The containment height is 20.3 m, the volume is 850 m 3 , the design pressure is 5 bar, and quantities of sodium up to 1250 kg can be sprayed or spilled for sodium combustion product aerosol sources. Instrumentation is provided for characterization of the aerosol and the containment atmosphere. This paper describes the aerosol sampling techniques and instruments used in the CSTF and discusses their accuracy and reproducibility

  7. More Realistic Face Model Surface Improves Relevance of Pediatric In-Vitro Aerosol Studies.

    Science.gov (United States)

    Amirav, Israel; Halamish, Asaf; Gorenberg, Miguel; Omar, Hamza; Newhouse, Michael T

    2015-01-01

    Various hard face models are commonly used to evaluate the efficiency of aerosol face masks. Softer more realistic "face" surface materials, like skin, deform upon mask application and should provide more relevant in-vitro tests. Studies that simultaneously take into consideration many of the factors characteristic of the in vivo face are lacking. These include airways, various application forces, comparison of various devices, comparison with a hard-surface model and use of a more representative model face based on large numbers of actual faces. To compare mask to "face" seal and aerosol delivery of two pediatric masks using a soft vs. a hard, appropriately representative, pediatric face model under various applied forces. Two identical face models and upper airways replicas were constructed, the only difference being the suppleness and compressibility of the surface layer of the "face." Integrity of the seal and aerosol delivery of two different masks [AeroChamber (AC) and SootherMask (SM)] were compared using a breath simulator, filter collection and realistic applied forces. The soft "face" significantly increased the delivery efficiency and the sealing characteristics of both masks. Aerosol delivery with the soft "face" was significantly greater for the SM compared to the AC (pmasks was observed with the hard "face." The material and pliability of the model "face" surface has a significant influence on both the seal and delivery efficiency of face masks. This finding should be taken into account during in-vitro aerosol studies.

  8. Research on aerosol formation, aerosol behaviour, aerosol filtration, aerosol measurement techniques and sodium fires at the Laboratory for Aerosol Physics and Filter Technology at the Nuclear Research Center Karlsruhe

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, S; Schikarski, W; Schoeck, W [Gesellschaft fuer Kernforschung mbH, Karlsruhe (Germany)

    1977-01-01

    The behaviour of aerosols in LMFBR plant systems is of great importance for a number of problems, both normal operational and accident kind. This paper covers the following: aerosol modelling for LMFBR containment systems; aerosol size spectrometry by laser light scattering; experimental facilities and experimental results concerned with aerosol release under accident conditions; filtration of sodium oxide aerosols by multilayer sand bed filters.

  9. Research on aerosol formation, aerosol behaviour, aerosol filtration, aerosol measurement techniques and sodium fires at the Laboratory for Aerosol Physics and Filter Technology at the Nuclear Research Center Karlsruhe

    International Nuclear Information System (INIS)

    Jordan, S.; Schikarski, W.; Schoeck, W.

    1977-01-01

    The behaviour of aerosols in LMFBR plant systems is of great importance for a number of problems, both normal operational and accident kind. This paper covers the following: aerosol modelling for LMFBR containment systems; aerosol size spectrometry by laser light scattering; experimental facilities and experimental results concerned with aerosol release under accident conditions; filtration of sodium oxide aerosols by multilayer sand bed filters

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

    Science.gov (United States)

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

    1981-01-01

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

  11. Dissolved organic matter in sea spray: a transfer study from marine surface water to aerosols

    Science.gov (United States)

    Schmitt-Kopplin, P.; Liger-Belair, G.; Koch, B. P.; Flerus, R.; Kattner, G.; Harir, M.; Kanawati, B.; Lucio, M.; Tziotis, D.; Hertkorn, N.; Gebefügi, I.

    2012-04-01

    Atmospheric aerosols impose direct and indirect effects on the climate system, for example, by absorption of radiation in relation to cloud droplets size, on chemical and organic composition and cloud dynamics. The first step in the formation of Organic primary aerosols, i.e. the transfer of dissolved organic matter from the marine surface into the atmosphere, was studied. We present a molecular level description of this phenomenon using the high resolution analytical tools of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and nuclear magnetic resonance spectroscopy (NMR). Our experiments confirm the chemoselective transfer of natural organic molecules, especially of aliphatic compounds from the surface water into the atmosphere via bubble bursting processes. Transfer from marine surface water to the atmosphere involves a chemical gradient governed by the physicochemical properties of the involved molecules when comparing elemental compositions and differentiating CHO, CHNO, CHOS and CHNOS bearing compounds. Typical chemical fingerprints of compounds enriched in the aerosol phase were CHO and CHOS molecular series, smaller molecules of higher aliphaticity and lower oxygen content, and typical surfactants. A non-targeted metabolomics analysis demonstrated that many of these molecules corresponded to homologous series of oxo-, hydroxy-, methoxy-, branched fatty acids and mono-, di- and tricarboxylic acids as well as monoterpenes and sugars. These surface active biomolecules were preferentially transferred from surface water into the atmosphere via bubble bursting processes to form a significant fraction of primary organic aerosols. This way of sea spray production leaves a selective biological signature of the surface water in the corresponding aerosol that may be transported into higher altitudes up to the lower atmosphere, thus contributing to the formation of secondary organic aerosol on a global scale or transported laterally with

  12. Lidar and aerosol measurements over the surf zone

    NARCIS (Netherlands)

    Moerman, M.M.; Cohen, L.H.; Leeuw, G. de; Kunz, G.J.

    2001-01-01

    The aerosol produced by waves breaking in the surf zone is important for a variety of processes, such as transport of pollutants and bacteria, and electro optical propagation in the coastal zone. Yet, quantitative information on surf produced aerosol is very limited (de Leeuw et al., 2000). In the

  13. Atmospheric aerosol in an urban area: Comparison of measurement instruments and methodologies and pulmonary deposition assessment

    International Nuclear Information System (INIS)

    Berico, M.; Luciani, A.; Formignani, M.

    1996-07-01

    In March 1995 a measurement campaign of atmospheric aerosol in the Bologna urban area (Italy) was carried out. A transportable laboratory, set up by ENEA (Italian national Agency for New Technologies, Energy and the Environment) Environmental Department (Bologna), was utilized with instruments for measurement of atmospheric aerosol and meteorological parameters. The aim of this campaign was of dual purpose: to characterize aerosol in urban area and to compare different instruments and methodologies of measurements. Mass concentrations measurements, evaluated on a 23-hour period with total filter, PM10 dichotomous sampler and low pressure impactor (LPI Berner), have provided information respectively about total suspended particles, respirable fraction and granulometric parameters of aerosol. Eight meteorologic parameters, number concentration of submicromic fraction of aerosol and mass concentration of micromic fraction have been continually measured. Then, in a daytime period, several number granulometries of atmospheric aerosol have also been estimated by means of diffusion battery system. Results related to different measurement methodologies and granulometric characteristics of aerosol are presented here. Pulmonary deposition of atmospheric aerosol is finally calculated, using granulometries provided by LPI Brener and ICRP 66 human respiratory tract model

  14. Confinement of surface waves at the air-water interface to control aerosol size and dispersity

    Science.gov (United States)

    Nazarzadeh, Elijah; Wilson, Rab; King, Xi; Reboud, Julien; Tassieri, Manlio; Cooper, Jonathan M.

    2017-11-01

    The precise control over the size and dispersity of droplets, produced within aerosols, is of great interest across many manufacturing, food, cosmetic, and medical industries. Amongst these applications, the delivery of new classes of high value drugs to the lungs has recently attracted significant attention from pharmaceutical companies. This is commonly achieved through the mechanical excitation of surface waves at the air liquid interface of a parent liquid volume. Previous studies have established a correlation between the wavelength on the surface of liquid and the final aerosol size. In this work, we show that the droplet size distribution of aerosols can be controlled by constraining the liquid inside micron-sized cavities and coupling surface acoustic waves into different volumes of liquid inside micro-grids. In particular, we show that by reducing the characteristic physical confinement size (i.e., either the initial liquid volume or the cavities' diameters), higher harmonics of capillary waves are revealed with a consequent reduction of both aerosol mean size and dispersity. In doing so, we provide a new method for the generation and fine control of aerosols' sizes distribution.

  15. MAX-DOAS aerosol and trace gases measurements in megacities in China

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xin [Institut fuer Energie- und Klimaforschung, Forschungszentrum Juelich (Germany); College of Environmental Science and Engineering Peking University, Beijing (China); Brauers, Theo [Institut fuer Energie- und Klimaforschung, Forschungszentrum Juelich (Germany); Shao, Min [College of Environmental Science and Engineering Peking University, Beijing (China)

    2011-07-01

    Multi Axis Differential Optical Absorption Spectroscopy (MAXDOAS) is a new remote sensing technique to measure atmospheric trace gases. Compared to other areas in the world, the atmospheric observations in megacities in China are rather limited. We present MAX-DOAS measurements at four sites in Beijing and Guangzhou in 2006 and 2008. At each site, the scattered sunlight was recorded at 7 elevation angles for about 1 months. Using the zenith spectrum as reference, the Differential Slant Column Densities (DSCDs) of HCHO, CHOCHO, O{sub 4} and NO{sub 2} at offaxis viewing geometries were derived from the DOAS fit. These DSCDs were simulated using a backward Monte Carlo radiative transfer model. The aerosol and trace gas profiles were defined by 3 parameters: the integrated quantities (T), the height of the surface layer (H), and the fraction of T below H. We fitted the modeled values to the measured values at the corresponding viewing geometries by varying the 3 parameters. The aerosol extinction and the boundary layer height were successfully retrieved from the measured O{sub 4} DSCDs as well as ground level concentrations of CHOCHO, HCHO, and NO{sub 2}, the latter being compared to simultaneous in-situ measurements.

  16. The Influence of Anthropogenic Greenhouse Gases and Aerosols on the Surface Heat and Moisture Budgets.

    Science.gov (United States)

    Ramaswamy, V.; Freidenreich, S.; Ginoux, P. A.; Ming, Y.; Paynter, D.; Persad, G.; Schwarzkopf, M. D.

    2017-12-01

    Emissions of greenhouse gases and aerosols alter atmospheric composition and `force' major perturbations in the radiative fluxes at the top-of-the-atmosphere and surface. In this paper, we discuss the radiative changes caused by anthropogenic greenhouse gases and aerosols at the surface, and its importance in the context of effects on the global hydrologic cycle. An important characteristic of imbalances forced by radiative species is the tendency for responses to occur in the non-radiative components, in order for the surface energy and moisture budgets to re-establish equilibrium. Using the NOAA/ GFDL global climate models used in CMIP3 and CMIP5, and to be used in CMIP6, we investigate how the surface energy balance has evolved with time under the action of the emissions, and the manner of changes in the surface radiative, sensible and latent heat components. We diagnose the relative importance of the forcings on the global and continental scales, the differing mechanisms due to greenhouse gases and aerosols on surface heat and moisture budgets, and the relative roles of the atmospheric constituents on precipitation and evaporation. Scattering and absorbing properties of aerosols can have contrasting effects on precipitation, with the aerosol indirect effect presenting another complication owing to the uncertainty in its magnitude. We compare the modeled surface flux changes against observations made from multiple platforms over the 20th and the early period of the 21st centuries, and asses the models' strengths and weaknesses. We also explore the consequences for the surface balance and precipitation in the 21st century under various emission scenarios.

  17. Calculation of color difference and measurement of the spectrum of aerosol based on human visual system

    Science.gov (United States)

    Dai, Mengyan; Liu, Jianghai; Cui, Jianlin; Chen, Chunsheng; Jia, Peng

    2017-10-01

    In order to solve the problem of the quantitative test of spectrum and color of aerosol, the measurement method of spectrum of aerosol based on human visual system was proposed. The spectrum characteristics and color parameters of three different aerosols were tested, and the color differences were calculated according to the CIE1976-L*a*b* color difference formula. Three tested powders (No 1# No 2# and No 3# ) were dispersed in a plexglass box and turned into aerosol. The powder sample was released by an injector with different dosages in each experiment. The spectrum and color of aerosol were measured by the PRO 6500 Fiber Optic Spectrometer. The experimental results showed that the extinction performance of aerosol became stronger and stronger with the increase of concentration of aerosol. While the chromaticity value differences of aerosols in the experiment were so small, luminance was verified to be the main influence factor of human eye visual perception and contributed most in the three factors of the color difference calculation. The extinction effect of No 3# aerosol was the strongest of all and caused the biggest change of luminance and color difference which would arouse the strongest human visual perception. According to the sensation level of chromatic color by Chinese, recognition color difference would be produced when the dosage of No 1# powder was more than 0.10 gram, the dosage of No 2# powder was more than 0.15 gram, and the dosage of No 3# powder was more than 0.05 gram.

  18. Lead isotope measurements on aerosol samples with ICP-MS

    International Nuclear Information System (INIS)

    Widmer, C.R.; Kraehenbuehl, U.; Kramers, J.; Tobler, L.

    2000-01-01

    Size fractionated aerosols were collected with low pressure Berner impactors on a radio/TV tower 110 m above ground on a hill 10 km east of Bern at a total elevation of 1060 m asl. Two different wind sectors were chosen with the goal of assessing any differences in lead concentration and the 3 radiogenic lead isotopes (206,207,208) for east and west wind, respectively. A leaching technique was used to extract the lead quantitatively from the surface of the impaction foils. This method has been proven to be better suited for airborne particles than complete microwave digestion because it is less time consuming and contamination risk is smaller. Blank considerations played a major role in choosing all the chemicals, tubes, beakers and selecting the analytical method. Lead concentrations were determined with GF-AAS and lead isotopes with two different ICP-MS systems, one being a multicollector system. Precision of the simultaneous multicollector system was found to be at least a factor of 3 better than that of the sequentially operating ICP-MS. The small variations in isotope ratios from the two wind sectors can be distinctly seen with this enhanced precision. The observed relative difference in isotope ratios between east- and westwind was ∝0.6% for 207 Pb/ 206 Pb and ∝0.5% for 208 Pb/ 206 Pb. (orig.)

  19. A technique for rapid source apportionment applied to ambient organic aerosol measurements from a thermal desorption aerosol gas chromatograph (TAG

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2016-11-01

    Full Text Available We present a rapid method for apportioning the sources of atmospheric organic aerosol composition measured by gas chromatography–mass spectrometry methods. Here, we specifically apply this new analysis method to data acquired on a thermal desorption aerosol gas chromatograph (TAG system. Gas chromatograms are divided by retention time into evenly spaced bins, within which the mass spectra are summed. A previous chromatogram binning method was introduced for the purpose of chromatogram structure deconvolution (e.g., major compound classes (Zhang et al., 2014. Here we extend the method development for the specific purpose of determining aerosol samples' sources. Chromatogram bins are arranged into an input data matrix for positive matrix factorization (PMF, where the sample number is the row dimension and the mass-spectra-resolved eluting time intervals (bins are the column dimension. Then two-dimensional PMF can effectively do three-dimensional factorization on the three-dimensional TAG mass spectra data. The retention time shift of the chromatogram is corrected by applying the median values of the different peaks' shifts. Bin width affects chemical resolution but does not affect PMF retrieval of the sources' time variations for low-factor solutions. A bin width smaller than the maximum retention shift among all samples requires retention time shift correction. A six-factor PMF comparison among aerosol mass spectrometry (AMS, TAG binning, and conventional TAG compound integration methods shows that the TAG binning method performs similarly to the integration method. However, the new binning method incorporates the entirety of the data set and requires significantly less pre-processing of the data than conventional single compound identification and integration. In addition, while a fraction of the most oxygenated aerosol does not elute through an underivatized TAG analysis, the TAG binning method does have the ability to achieve molecular level

  20. Tethered balloon operation for wintering aerosol measurements in the lower troposphere at Syowa Station, Antarctica

    OpenAIRE

    Keiichiro Hara; Kazuo Osada; Takashi Yamanouchi

    2007-01-01

    The 46th Japanese Antarctic Research Expedition (JARE-46) carried out twenty seven tethered-balloon-borne aerosol measurements at Syowa Station for better understanding of aerosol chemical and physical properties in the lower troposphere from 6th January 2005 until 11 December 2005. This report summarizes the plan, preparation, field activities and some troubles/problems in the tethered-balloon observations.

  1. Impacts of dust aerosol and adjacency effects on the accuracy of Landsat 8 and RapidEye surface reflectances

    KAUST Repository

    Houborg, Rasmus; McCabe, Matthew

    2017-01-01

    The atmospheric correction of satellite data is challenging over desert agricultural systems, due to the relatively high aerosol optical thicknesses (τ550), bright soils, and a heterogeneous surface reflectance field. Indeed, the contribution of reflected radiation from adjacent pixels scattered into the field of view of a target pixel is considerable and can significantly affect the fidelity of retrieved reflectances. In this study, uncertainties and quantitative errors associated with the atmospheric correction of multi-spectral Landsat 8 and RapidEye data were characterized over a desert agricultural landscape in Saudi Arabia. Surface reflectances were retrieved using an implementation of the 6SV atmospheric correction code, and validated against field collected spectroradiometer measurements over desert, cultivated soil, and vegetated surface targets. A combination of satellite and Aerosol Robotic Network (AERONET) data were used to parameterize aerosol properties and atmospheric state parameters. With optimal specification of τ550 and aerosol optical properties and correction for adjacency effects, the relative Mean Absolute Deviation (MAD) for all bands combined was 5.4% for RapidEye and 6.8% for Landsat 8. However uncertainties associated with satellite-based τ550 retrievals were shown to introduce significant error into the reflectance estimates. With respect to deriving common vegetation indices from corrected reflectance data, the Normalized Difference Vegetation Index (NDVI) was associated with the smallest errors (3–8% MAD). Surface reflectance errors were highest for bands in the visible part of the spectrum, particularly the blue band (5–16%), while there was more consistency within the red-edge (~ 5%) and near-infrared (5–7%). Results were generally better constrained when a τ550-dependent aerosol model for desert dust particles, parameterized on the basis of nearby AERONET site data, was used in place of a generic rural or background

  2. Impacts of dust aerosol and adjacency effects on the accuracy of Landsat 8 and RapidEye surface reflectances

    KAUST Repository

    Houborg, Rasmus

    2017-03-29

    The atmospheric correction of satellite data is challenging over desert agricultural systems, due to the relatively high aerosol optical thicknesses (τ550), bright soils, and a heterogeneous surface reflectance field. Indeed, the contribution of reflected radiation from adjacent pixels scattered into the field of view of a target pixel is considerable and can significantly affect the fidelity of retrieved reflectances. In this study, uncertainties and quantitative errors associated with the atmospheric correction of multi-spectral Landsat 8 and RapidEye data were characterized over a desert agricultural landscape in Saudi Arabia. Surface reflectances were retrieved using an implementation of the 6SV atmospheric correction code, and validated against field collected spectroradiometer measurements over desert, cultivated soil, and vegetated surface targets. A combination of satellite and Aerosol Robotic Network (AERONET) data were used to parameterize aerosol properties and atmospheric state parameters. With optimal specification of τ550 and aerosol optical properties and correction for adjacency effects, the relative Mean Absolute Deviation (MAD) for all bands combined was 5.4% for RapidEye and 6.8% for Landsat 8. However uncertainties associated with satellite-based τ550 retrievals were shown to introduce significant error into the reflectance estimates. With respect to deriving common vegetation indices from corrected reflectance data, the Normalized Difference Vegetation Index (NDVI) was associated with the smallest errors (3–8% MAD). Surface reflectance errors were highest for bands in the visible part of the spectrum, particularly the blue band (5–16%), while there was more consistency within the red-edge (~ 5%) and near-infrared (5–7%). Results were generally better constrained when a τ550-dependent aerosol model for desert dust particles, parameterized on the basis of nearby AERONET site data, was used in place of a generic rural or background

  3. Measured Mass-Normalized Optical Cross Sections For Aerosolized Organophosphorus Chemical Warfare Simulants

    National Research Council Canada - National Science Library

    Gurton, Kristan P; Felton, Melvin; Dahmani, Rachid; Ligon, David

    2007-01-01

    We present newly measured results of an ongoing experimental program established to measure optical cross sections in the mid and long wave infrared for a variety of chemical and biologically based aerosols...

  4. Airborne UV DIAL Measurements of Ozone and Aerosols

    Science.gov (United States)

    Grant, William B.; Browell, Edward V.

    2000-01-01

    The NASA Langley Research Center's airborne UV Differential Absorption Lidar (DIAL) system measures vertical profiles of ozone and aerosols above and below the aircraft along its flight track. This system has been used in over 20 airborne field missions designed to study the troposphere and stratosphere since 1980. Four of these missions involved tropospheric measurement programs in the Pacific Ocean with two in the western North Pacific and two in the South Pacific. The UV DIAL system has been used in these missions to study such things as pollution outflow, long-range transport, and stratospheric intrusions; categorize the air masses encountered; and to guide the aircraft to altitudes where interesting features can be studied using the in situ instruments. This paper will highlight the findings with the UV DIAL system in the Pacific Ocean field programs and introduce the mission planned for the western North Pacific for February-April 2001. This will be an excellent opportunity for collaboration between the NASA airborne mission and those with ground-based War systems in Asia Pacific Rim countries to make a more complete determination of the transport of air from Asia to the western Pacific.

  5. Urban Surface Temperature Reduction via the Urban Aerosol Direct Effect: A Remote Sensing and WRF Model Sensitivity Study

    Directory of Open Access Journals (Sweden)

    Menglin Jin

    2010-01-01

    Full Text Available The aerosol direct effect, namely, scattering and absorption of sunlight in the atmosphere, can lower surface temperature by reducing surface insolation. By combining National Aeronautics and Space Administration (NASA AERONET (AErosol RObotic NETwork observations in large cities with Weather Research and Forecasting (WRF model simulations, we find that the aerosol direct reduction of surface insolation ranges from 40–100Wm−2, depending on aerosol loading and land-atmosphere conditions. To elucidate the maximum possible effect, values are calculated using a radiative transfer model based on the top quartile of the multiyear instantaneous aerosol data observed by AERONET sites. As a result, surface skin temperature can be reduced by 1°C-2°C while 2-m surface air temperature reductions are generally on the order of 0.5°C–1°C.

  6. Remote Sensing of Aerosol Backscatter and Earth Surface Targets By Use of An Airborne Focused Continuous Wave CO2 Doppler Lidar Over Western North America

    Science.gov (United States)

    Jarzembski, Maurice A.; Srivastava, Vandana; Goodman, H. Michael (Technical Monitor)

    2000-01-01

    Airborne lidar systems are used to determine wind velocity and to measure aerosol or cloud backscatter variability. Atmospheric aerosols, being affected by local and regional sources, show tremendous variability. Continuous wave (cw) lidar can obtain detailed aerosol loading with unprecedented high resolution (3 sec) and sensitivity (1 mg/cubic meter) as was done during the 1995 NASA Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) mission over western North America and the Pacific Ocean. Backscatter variability was measured at a 9.1 micron wavelength cw focused CO2 Doppler lidar for approximately 52 flight hours, covering an equivalent horizontal distance of approximately 30,000 km in the troposphere. Some quasi-vertical backscatter profiles were also obtained during various ascents and descents at altitudes that ranged from approximately 0.1 to 12 km. Similarities and differences for aerosol loading over land and ocean were observed. Mid-tropospheric aerosol backscatter background mode was approximately 6 x 10(exp -11)/ms/r, consistent with previous lidar datasets. While these atmospheric measurements were made, the lidar also retrieved a distinct backscatter signal from the Earth's surface from the unfocused part of the focused cw lidar beam during aircraft rolls. Atmospheric backscatter can be highly variable both spatially and temporally, whereas, Earth-surface backscatter is relatively much less variant and can be quite predictable. Therefore, routine atmospheric backscatter measurements by an airborne lidar also give Earth surface backscatter which can allow for investigating the Earth terrain. In the case where the Earth's surface backscatter is coming from a well-known and fairly uniform region, then it can potentially offer lidar calibration opportunities during flight. These Earth surface measurements over varying Californian terrain during the mission were compared with laboratory backscatter measurements using the same lidar of various

  7. Longterm and spatial variability of Aerosol optical properties measured by sky radiometer in Japan sites

    Science.gov (United States)

    Aoki, K.

    2016-12-01

    Aerosols and cloud play an important role in the climate change. We started the long-term monitoring of aerosol and cloud optical properties since 1990's by using sky radiometer (POM-01, 02; Prede Co. Ltd., Japan). We provide the information, in this presentation, on the aerosol optical properties with respect to their temporal and spatial variability in Japan site (ex. Sapporo, Toyama, Kasuga and etc). The global distributions of aerosols have been derived from earth observation satellite and have been simulated in numerical models, which assume optical parameters. However, these distributions are difficult to derive because of variability in time and space. Therefore, Aerosol optical properties were investigated using the measurements from ground-based and ship-borne sky radiometer. The sky radiometer is an automatic instrument that takes observations only in daytime under the clear sky conditions. Observation of diffuse solar intensity interval was made every ten or five minutes by once. The aerosol optical properties were computed using the SKYRAD.pack version 4.2. The obtained Aerosol optical properties (Aerosol optical thickness, Ångström exponent, Single scattering albedo, and etc.) and size distribution volume clearly showed spatial and temporal variability in Japan area. In this study, we present the temporal and spatial variability of Aerosol optical properties at several Japan sites, applied to validation of satellite and numerical models. This project is validation satellite of GCOM-C, JAXA. The GCOM-C satellite scheduled to be launched in early 2017.

  8. Aerosol deposition velocities on the Pacific and Atlantic oceans calculated from 7Be measurements

    International Nuclear Information System (INIS)

    Young, J.A.; Silker, W.B.

    1979-01-01

    The concentrations of 7 Be were measured in Pacific and Atlantic ocean water for past several years to determine the deposition velocity of aerosol particles on the ocean surface. Beryllium-7 is produced at a relatively constant rate in the atmosphere by spallation reactions of cosmic rays with atmospheric nitrogen and oxygen. Immediately after its formation 7 Be becomes attached to aerosol particles, and therefore can serve as tracers of the subsequent behavior of these particles. Isopleths of 7 Be surface water concentration, 7 Be inventory in the ocean, and deposition velocity have been prepared for the Pacific Ocean from 30 0 S to 60 0 N and for the Atlantic Ocean from 10 0 N to 55 0 N. The concentrations, inventories and deposition velocities tended to be higher in regions where precipitation was high, and generally increased with latitude. The average flux of 7 Be across the ocean surface was calculated to be 0.027 atoms cm -2 sec -1 which is probably not significantly greater than the worldwide average 7 Be flux across land and ocean surfaces of 0.022 atoms cm -2 sec -1 calculated by Lal and Peters. The average deposition velocity was calculated to be 0.80 cm sec -1 . This value may be 10 to 30% too low, since it was calculated using atmospheric 7 Be concentrations which were measured at continental stations. Measurements of atmospheric 7 Be concentrations at ocean stations suggest that the concentrations at the continental stations averaged 10 to 30% higher than the concentrations over the ocean

  9. Aerosol deposition velocities on the Pacific and Atlantic oceans calculated from 7Be measurements

    International Nuclear Information System (INIS)

    Young, J.A.; Silker, W.B.

    1980-01-01

    The concentrations of 7 Be have been measured in Pacific and Atlantic ocean water for the past several years to determine the deposition velocity of aerosol particles on the ocean surface. 7 Be is produced at a relatively constant rate in the atmosphere by spallation reactions of cosmic rays with atmospheric nitrogen and oxygen. Immediately after its formation 7 Be becomes attached to aerosol particles, and therefore can serve as tracers of the subsequent behavior of these particles. Isopleths of 7 Be surface water concentrations, 7 Be inventory in the ocean, and deposition velocity have been prepared for the Pacific Ocean from 30 0 S to 60 0 N and for the Atlantic Ocean from 10 0 N to 55 0 N. The concentrations, inventories and deposition velocities tended to be higher in regions where precipitation was high, and generally increased with latitude. The average flux of 7 Be across the ocean surface was calculated to be 0.027 atoms cm -2 s -1 which is probably not significantly greater than the worldwide average 7 Be flux across land and ocean surfaces of 0.022 atoms cm -2 s -1 calculated by Lal and Peters. The average deposition velocity was calculated to be 0.80 cm s -1 . This value may be 10-50% too low, since it was calculated using atmospheric 7 Be concentrations which were measured at continental stations. Measurements of atmospheric 7 Be concentrations at ocean stations suggest that the concentrations at the continental stations averaged 10-50% higher than the concentrations over the ocean. (orig.)

  10. SAFARI 2000 Atmospheric Aerosol Measurements, Hand-held Hazemeters, Zambia

    Data.gov (United States)

    National Aeronautics and Space Administration — In conjunction with the AERONET (AErosol RObotic NETwork) participation in SAFARI 2000, the USDA Forest Service deployed handheld hazemeters in western Zambia from...

  11. Armor Plate Surface Roughness Measurements

    National Research Council Canada - National Science Library

    Stanton, Brian; Coburn, William; Pizzillo, Thomas J

    2005-01-01

    ...., surface texture and coatings) that could become important at high frequency. We measure waviness and roughness of various plates to know the parameter range for smooth aluminum and rolled homogenous armor (RHA...

  12. Particle size distributions of radioactive aerosols measured in workplaces

    International Nuclear Information System (INIS)

    Dorrian, M.-D.; Bailey, M.R.

    1995-01-01

    A survey of published values of Activity Median Aerodynamic Diameter (AMAD) measured in working environments was conducted to assist in the selection of a realistic default AMAD for occupational exposures. Results were compiled from 52 publications covering a wide variety of industries and workplaces. Reported values of AMAD from all studies ranged from 0.12 μm to 25 μm, and most were well fitted by a log-normal distribution with a median value of 4.4 μm. This supports the choice of a 5 μm default AMAD, as a realistic rounded value for occupational exposures, by the ICRP Task Group on Human Respiratory Tract Models for Radiological Protection and its acceptance by ICRP. Both the nuclear power and nuclear fuel handling industries gave median values of approximately 4 μm. Uranium mills gave a median value of 6.8 μm with AMADs frequently greater than 10 μm. High temperature and arc saw cutting operations generated submicron particles and occasionally, biomodal log-normal particle size distributions. It is concluded that in view of the wide range of AMADs found in the surveyed literature, greater emphasis should be placed on air sampling to characterise aerosol particle size distributions for individual work practices, especially as doses estimated with the new 5 μm default AMAD will not always be conservative. (author)

  13. Biomass Burning Aerosol Absorption Measurements with MODIS Using the Critical Reflectance Method

    Science.gov (United States)

    Zhu, Li; Martins, Vanderlei J.; Remer, Lorraine A.

    2010-01-01

    This research uses the critical reflectance technique, a space-based remote sensing method, to measure the spatial distribution of aerosol absorption properties over land. Choosing two regions dominated by biomass burning aerosols, a series of sensitivity studies were undertaken to analyze the potential limitations of this method for the type of aerosol to be encountered in the selected study areas, and to show that the retrieved results are relatively insensitive to uncertainties in the assumptions used in the retrieval of smoke aerosol. The critical reflectance technique is then applied to Moderate Resolution Imaging Spectrometer (MODIS) data to retrieve the spectral aerosol single scattering albedo (SSA) in South African and South American 35 biomass burning events. The retrieved results were validated with collocated Aerosol Robotic Network (AERONET) retrievals. One standard deviation of mean MODIS retrievals match AERONET products to within 0.03, the magnitude of the AERONET uncertainty. The overlap of the two retrievals increases to 88%, allowing for measurement variance in the MODIS retrievals as well. The ensemble average of MODIS-derived SSA for the Amazon forest station is 0.92 at 670 nm, and 0.84-0.89 for the southern African savanna stations. The critical reflectance technique allows evaluation of the spatial variability of SSA, and shows that SSA in South America exhibits higher spatial variation than in South Africa. The accuracy of the retrieved aerosol SSA from MODIS data indicates that this product can help to better understand 44 how aerosols affect the regional and global climate.

  14. Aerosol Observing System (AOS) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Jefferson, A

    2011-01-17

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

  15. ACCENT-BIAFLUX workshop 2005, trace gas and aerosol flux measurement and techniques. Abstract book

    Energy Technology Data Exchange (ETDEWEB)

    Werner, A.; Soerensen, L.L. (eds.)

    2005-04-01

    The woorkshop trace gas and aerosol flux measurement techniques in the second meeting within the Biosphere Atmosphere Exchange of Pollutions (BIAFLUX) group in the EU-network project Atmospheric Composition Change (ACCENT). The goal of the workshop is to obtain an overview of techniques for measurements of gas and aerosol fluxes and to gather the knowledge of uncertainties in flux measurements and calculations. The workshop is funded by ACCENT. The abstract book presents abstracts of 21 oral presentations and 26 poster presentations. (LN)

  16. Atmo-metabolomics: a new measurement approach for investigating aerosol composition and ecosystem functioning.

    Science.gov (United States)

    Rivas-Ubach, A.; Liu, Y.; Sardans, J.; Tfaily, M. M.; Kim, Y. M.; Bourrianne, E.; Paša-Tolić, L.; Penuelas, J.; Guenther, A. B.

    2016-12-01

    Aerosols play crucial roles in the processes controlling the composition of the atmosphere and the functioning of ecosystems. Gaining a deeper understanding of the chemical composition of aerosols is one of the major challenges for atmospheric and climate scientists and is beginning to be recognized as important for ecological research. Better comprehension of aerosol chemistry can potentially provide valuable information on atmospheric processes such as oxidation of organics and the production of cloud condensation nuclei as well as provide an approximation of the general status of an ecosystem through the measurement of certain stress biomarkers. In this study, we describe an efficient aerosol sampling method, the metabolite extraction and the analytical procedures for the chemical characterization of aerosols, namely, the atmo-metabolome. We used mass spectrometry (MS) coupled to liquid chromatography (LC-MS), gas chromatography (GC-MS) and Fourier transform ion cyclotron resonance (FT-ICR-MS) to characterize the atmo-metabolome of two marked seasons; spring and summer. Our sampling and extraction methods demonstrated to be suitable for aerosol chemical characterization with any of the analytical platforms used in this study. The atmo-metabolome between spring and summer showed overall statistically differences. We identified several metabolites that can be attributed to pollen and other plant-related aerosols. Spring aerosols exhibit higher concentrations of metabolites linked to higher plant activity while summer samples had higher concentrations of metabolites that may reflect certain oxidative stresses in primary producers. Moreover, the elemental composition of aerosols showed clear different between seasons. Summer aerosols were generally higher in molecular weight and with higher O/C ratios, indicating higher oxidation levels and condensation of compounds relative to spring. Our method represents an advanced approach for characterizing the composition of

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-04-01

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

  18. Maritime Aerosol optical properties measured by ship-borne sky radiometer

    Science.gov (United States)

    Aoki, K.

    2017-12-01

    Maritime aerosols play an important role in the earth climate change. We started the measurements of aerosol optical properties since 1994 by using ship-borne sky radiometer (POM-01 MK-II and III; Prede Co. Ltd., Japan) over the ocean. We report the results of an aerosol optical properties over the ocean by using Research Vessel of the ship-borne sky radiometers. Aerosol optical properties observation were made in MR10-02 to MR16-09 onboard the R/V Mirai, JAMSTEC. The sky radiometer measure the direct and diffuse solar radiance with seven interference filters (0.315, 0.4, 0.5, 0.675, 0.87, 0.94, and 1.02 µm). Observation interval was made every five minutes by once, only in daytime under the clear sky conditions. GPS provides the position with longitude and latitude and heading direction of the vessel, and azimuth and elevation angle of the sun. The aerosol optical properties were computed using the SKYRAD.pack version 4.2. The obtained Aerosol optical properties (Aerosol optical thickness, Ångström exponent, Single scattering albedo, and etc.) and size distribution volume clearly showed spatial and temporal variability over the ocean. Aerosol optical thickness found over the near the coast (Asia and Tropical area) was high and variable. The size distribution volume have peaks at small particles at Asian coast and large particles at Tropical coast area. We provide the information, in this presentation, on the aerosol optical properties measurements with temporal and spatial variability in the Maritime Aerosol. This project is validation satellite of GCOM-C/SGLI, JAXA and other. The GCOM-C satellite scheduled to be launched in 2017 JFY.

  19. Factor analysis of combined organic and inorganic aerosol mass spectra from high resolution aerosol mass spectrometer measurements

    Directory of Open Access Journals (Sweden)

    Y. L. Sun

    2012-09-01

    Full Text Available Positive matrix factorization (PMF was applied to the merged high resolution mass spectra of organic and inorganic aerosols from aerosol mass spectrometer (AMS measurements to investigate the sources and evolution processes of submicron aerosols in New York City in summer 2009. This new approach is able to study the distribution of organic and inorganic species in different types of aerosols, the acidity of organic aerosol (OA factors, and the fragment ion patterns related to photochemical processing. In this study, PMF analysis of the unified AMS spectral matrix resolved 8 factors. The hydrocarbon-like OA (HOA and cooking OA (COA factors contain negligible amounts of inorganic species. The two factors that are primarily ammonium sulfate (SO4-OA and ammonium nitrate (NO3-OA, respectively, are overall neutralized. Among all OA factors the organic fraction of SO4-OA shows the highest degree of oxidation (O/C = 0.69. Two semi-volatile oxygenated OA (OOA factors, i.e., a less oxidized (LO-OOA and a more oxidized (MO-OOA, were also identified. MO-OOA represents local photochemical products with a diurnal profile exhibiting a pronounced noon peak, consistent with those of formaldehyde (HCHO and Ox(= O3 + NO2. The NO+/NO2+ ion ratio in MO-OOA is much higher than that in NO3-OA and in pure ammonium nitrate, indicating the formation of organic nitrates. The nitrogen-enriched OA (NOA factor contains ~25% of acidic inorganic salts, suggesting the formation of secondary OA via acid-base reactions of amines. The size distributions of OA factors derived from the size-resolved mass spectra show distinct diurnal evolving behaviors but overall a progressing evolution from smaller to larger particle mode as the oxidation degree of OA increases. Our results demonstrate that PMF analysis of the unified aerosol mass spectral matrix which contains both

  20. Artefacts for optical surface measurement

    Science.gov (United States)

    Robson, Stuart; Beraldin, J.-Angelo; Brownhill, Andrew; MacDonald, Lindsay

    2011-07-01

    Flexible manufacturing technologies are supporting the routine production of components with freeform surfaces in a wide variety of materials and surface finishes. Such surfaces may be exploited for both aesthetic and performance criteria for a wide range of industries, for example automotive, aircraft, small consumer goods and medial components. In order to ensure conformance between manufactured part and digital design it is necessary to understand, validate and promote best practice of the available measurement technologies. Similar, but currently less quantifiable, measurement requirements also exist in heritage, museum and fine art recording where objects can be individually hand crafted to extremely fine levels of detail. Optical 3D measurement systems designed for close range applications are typified by one or more illumination sources projecting a spot, line or structured light pattern onto a surface or surfaces of interest. Reflections from the projected light are detected in one or more imaging devices and measurements made concerning the location, intensity and optionally colour of the image. Coordinates of locations on the surface may be computed either directly from an understanding of the illumination and imaging geometry or indirectly through analysis of the spatial frequencies of the projected pattern. Regardless of sensing configuration some independent means is necessary to ensure that measurement capability will meet the requirements of a given level of object recording and is consistent for variations in surface properties and structure. As technologies mature, guidelines for best practice are emerging, most prominent at the current time being the German VDI/VDE 2634 and ISO/DIS 10360-8 guidelines. This considers state of the art capabilities for independent validation of optical non-contact measurement systems suited to the close range measurement of table top sized manufactured or crafted objects.

  1. Satellite-Surface Perspectives of Air Quality and Aerosol-Cloud Effects on the Environment: An Overview of 7-SEAS BASELInE

    Science.gov (United States)

    Tsay, Si-Chee; Maring, Hal B.; Lin, Neng-Huei; Buntoung, Sumaman; Chantara, Somporn; Chuang, Hsiao-Chi; Gabriel, Philip M.; Goodloe, Colby S.; Holben, Brent N.; Hsiao, Ta-Chih; hide

    2016-01-01

    The objectives of 7-SEASBASELInE (Seven SouthEast Asian Studies Biomass-burning Aerosols and Stratocumulus Environment: Lifecycles and Interactions Experiment) campaigns in spring 2013-2015 were to synergize measurements from uniquely distributed ground-based networks (e.g., AERONET (AErosol RObotic NETwork)), MPLNET ( NASA Micro-Pulse Lidar Network)) and sophisticated platforms (e.g.,SMARTLabs (Surface-based Mobile Atmospheric Research and Testbed Laboratories), regional contributing instruments), along with satellite observations retrievals and regional atmospheric transport chemical models to establish a critically needed database, and to advance our understanding of biomass-burning aerosols and trace gases in Southeast Asia (SEA). We present a satellite-surface perspective of 7-SEASBASELInE and highlight scientific findings concerning: (1) regional meteorology of moisture fields conducive to the production and maintenance of low-level stratiform clouds over land; (2) atmospheric composition in a biomass-burning environment, particularly tracers-markers to serve as important indicators for assessing the state and evolution of atmospheric constituents; (3) applications of remote sensing to air quality and impact on radiative energetics, examining the effect of diurnal variability of boundary-layer height on aerosol loading; (4) aerosol hygroscopicity and ground-based cloud radar measurements in aerosol-cloud processes by advanced cloud ensemble models; and (5) implications of air quality, in terms of toxicity of nanoparticles and trace gases, to human health. This volume is the third 7-SEAS special issue (after Atmospheric Research, vol. 122, 2013; and Atmospheric Environment, vol. 78, 2013) and includes 27 papers published, with emphasis on air quality and aerosol-cloud effects on the environment. BASELInE observations of stratiform clouds over SEA are unique, such clouds are embedded in a heavy aerosol-laden environment and feature characteristically greater

  2. Pulmonary deposition of urban atmospheric aerosol. Assessments of the mass, number and surface of the deposited particles; Deposizione polmonare dell'aerosol atmosferico urbano in termini di massa, numero e superficie delle particelle

    Energy Technology Data Exchange (ETDEWEB)

    Luciani, A.; Berico, M.; Castellani, C.M. [ENEA, Centro Ricerche Ezio Clementel, Bologna (Italy). Dipt. Ambiente

    1998-07-01

    Pulmonary deposition of urban atmospheric aerosol has been calculated by means of the data derived from March 1995 measurement campaign of urban aerosol. The human respiratory tract model of the International Commission on Radiological Protection (n. 66) developed for radiation protection purposes has been used. The number and surface of the deposited particles, as well as the mass, have been also evaluated. [Italian] I dati relativi alla campagna di misure effettuata nel marzo 1995 sono stati rielaborati al fine di valutare la deposizione polmonare dell'aerosol atmosferico in area urbana. Le valutazioni di deposizione nel tratto respiratorio umano sono state condotte mediante l'utilizzo del modello del tratto respiratorio umano presentato per fini radioprotezionistici dalla International Commission on Radiological Protection (n. 66). Sono state effettuate valutazioni di deposizione in massa e in termini di numero e superficie delle particelle.

  3. Optical transmission through aerosol deposits on diffusely reflective filters: a method for measuring the absorbing component of aerosol particles

    International Nuclear Information System (INIS)

    Rosen, H.; Novakov, T.

    1983-01-01

    It is unclear why the backscattered radiation from nonabsorbing particles should not make a significant contribution to the optical attenuation measurement. This is especially true where the absorbing component represents only a very small fraction of the aerosol mass. In this Letter we present a simple theoretical model which accounts for all these observations and points out the critical role of the filter substrate as an almost perfect diffuse reflector in the technique

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

    Science.gov (United States)

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

    1981-01-01

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

  5. Atmospheric aerosol in an urban area: Comparison of measurement instruments and methodologies and pulmonary deposition assessment; Aerosol atmosferico in area urbanae di misura e valutazione di deposizione polmonare

    Energy Technology Data Exchange (ETDEWEB)

    Berico, M; Luciani, A; Formignani, M [ENEA, Centro Ricerche Bologna (Italy). Dip. Ambiente

    1996-07-01

    In March 1995 a measurement campaign of atmospheric aerosol in the Bologna urban area (Italy) was carried out. A transportable laboratory, set up by ENEA (Italian national Agency for New Technologies, Energy and the Environment) Environmental Department (Bologna), was utilized with instruments for measurement of atmospheric aerosol and meteorological parameters. The aim of this campaign was of dual purpose: to characterize aerosol in urban area and to compare different instruments and methodologies of measurements. Mass concentrations measurements, evaluated on a 23-hour period with total filter, PM10 dichotomous sampler and low pressure impactor (LPI Berner), have provided information respectively about total suspended particles, respirable fraction and granulometric parameters of aerosol. Eight meteorologic parameters, number concentration of submicromic fraction of aerosol and mass concentration of micromic fraction have been continually measured. Then, in a daytime period, several number granulometries of atmospheric aerosol have also been estimated by means of diffusion battery system. Results related to different measurement methodologies and granulometric characteristics of aerosol are presented here. Pulmonary deposition of atmospheric aerosol is finally calculated, using granulometries provided by LPI Brener and ICRP 66 human respiratory tract model.

  6. Atmospheric aerosol load morphological classification and retrieved visibility based on lidar backscatter measurements

    CSIR Research Space (South Africa)

    Tesfaye, M

    2010-01-01

    Full Text Available In this paper, the tropospheric aerosol load morphological classification and its impact on temporal variation of visibility are investigated using a continuous 23-hour single channel CSIR-NLC mobile LIDAR backscatter measurement. The trajectory...

  7. Aerosol optical properties in the mega-cities Beijing and Guangzhou: Measurements and implications for regional air pollution, aerosol sources and remote sensing

    Science.gov (United States)

    Garland, R. M.; Yang, H.; Schmid, O.; Rose, D.; Gunthe, S. S.

    2009-04-01

    wavelength dependence (curvature) that was related to the ratio of fine and coarse particle mass (PM1/PM10) as well as the surface mode diameter of the fine particle fraction. The results demonstrate consistency between in situ measurements and a remote sensing formalism with regard to the fine particle fraction and volume mode diameter, but there are also systematic deviations for the larger mode diameters. Thus we suggest that more data sets from in situ measurements of aerosol optical parameters and particle size distributions should be used to evaluate formalisms applied in aerosol remote sensing. Moreover, we observed a negative correlation between single scattering albedo and backscatter fraction, and we found that it affects the impact that these parameters have on aerosol radiative forcing efficiency and should be considered in model studies of Beijing, Guangzhou and similarly polluted mega-city regions. References: Garland, R. M., Yang, H., Schmid, O., Rose, D., Nowak, A., Achtert, P., Wiedensohler, A., Takegawa, N., Kita, K., Miyazaki, Y., Kondo, Y., Hu, M., Shao, M., Zeng, L. M., Zhang, Y. H., Andreae, M. O., and Pöschl, U.: Aerosol optical properties in a rural environment near the mega-city Guangzhou, China: implications for regional air pollution, radiative forcing and remote sensing, Atmospheric Chemistry and Physics, 8, 5161-5186, 2008. Garland, R. M., Schmid, O., Rose, D., Nowak, A., Achtert, P., Wiedensohler, A., Gunthe, S.S., Takegawa, N., Kita, K., Kondo, Y., Hu, M., Shao, M., Zeng, L. M., Zhu, T., Andreae, M. O., and Pöschl, U.: Aerosol optical properties observed during CAREBeijing-2006: Characteristic differences between the inflow and outflow of Beijing city air, Journal of Geophysical Research - Atmospheres, in press, 2009.

  8. Kinetically controlled glass transition measurement of organic aerosol thin films using broadband dielectric spectroscopy

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2018-06-01

    Full Text Available Glass transitions from liquid to semi-solid and solid phase states have important implications for reactivity, growth, and cloud-forming (cloud condensation nuclei and ice nucleation capabilities of secondary organic aerosols (SOAs. The small size and relatively low mass concentration of SOAs in the atmosphere make it difficult to measure atmospheric SOA glass transitions using conventional methods. To circumvent these difficulties, we have adapted a new technique for measuring glass-forming properties of atmospherically relevant organic aerosols. Aerosol particles to be studied are deposited in the form of a thin film onto an interdigitated electrode (IDE using electrostatic precipitation. Dielectric spectroscopy provides dipole relaxation rates for organic aerosols as a function of temperature (373 to 233 K that are used to calculate the glass transition temperatures for several cooling or heating rates. IDE-enabled broadband dielectric spectroscopy (BDS was successfully used to measure the kinetically controlled glass transition temperatures of aerosols consisting of glycerol and four other compounds with selected cooling and heating rates. The glass transition results agree well with available literature data for these five compounds. The results indicate that the IDE-BDS method can provide accurate glass transition data for organic aerosols under atmospheric conditions. The BDS data obtained with the IDE-BDS technique can be used to characterize glass transitions for both simulated and ambient organic aerosols and to model their climate effects.

  9. Determination of the columnar aerosol size distribution by inversion of spectral aerosol optical depth measurements at different areas in Egypt

    International Nuclear Information System (INIS)

    EI-Metwally, M.; Madkour, M.A.

    2006-01-01

    Aerosols have a great effects on nuclear safety calculations and atmospheric environment. The aerosol optical depth measurements are carried out at four areas in Egypt: Cairo and Helwan as urban/industrial areas, Aswan as an arid area and Mansoura as an agricultural area covering the period from Jun 1992 to May 1993. These measurements were recorded by ground-based pyrheliometers with large band-pass filters. Monthly average values of aerosol optical depth (AOD) showed a pronounced temporal trend, with a maximum AOD during summer and the transition seasons (spring and autumn) at all sites. Levels of AODs are higher at both urban and industrial areas than at other areas. Variation of Angstrom exponent a with the AOD was clear at most sites and the a value depends on the spectral range used in its determination. The mean contribution of anthropogenic sources to AOD over Cairo was at the range of 25.1-54.3%, whereas those values in Helwan were at the range of 34.5-59.8%. Finally, columnar aerosol size distributions have been inferred by inverting particularly AOD measurements as a function of wavelength. The Junge (type I) and bimodal (type III) distributions are dominant at urban and arid areas (Cairo and Aswan), whereas mono dispersion distribution (type II) are dominant in industrial and agricultural areas (Helwan and Mansoura). In Cairo and Aswan, the peak of columnar size distribution for the fine mode at radius r is around 0.1 and 0.2 μm respectively, while it is around 1.0 and 2.0 μm for the coarse mode. .Also, the peak of size distribution for the mono dispersion mode was marked at radius around 0.2 μm at both Helwan and Mansoura. A comprehensive comparison of our results with literature size distributions is very sparse, nevertheless, our size distributions in general agree with them

  10. EXPERIMENTAL COMPARISON OF THE AEROSOL METHOD OF DISINFECTION OF AIR AND SURFACES CONTAMINATED BY M. TUBERCULOSIS

    Directory of Open Access Journals (Sweden)

    V. V. Kuzin

    2018-01-01

    Full Text Available The objective of the study: to analyze efficiency of an aerosol method of M. tuberculosis deactivation in the air and on surfaces versus the conventional methods of the disinfectants' application.Subjects and Methods. The article describes the evaluation of efficiency of the aerosol method of M. tuberculosis, H37Rv strain, deactivation on surfaces (tested objects made of linoleum and in the air using the disinfectant of Green Dez based on chlorine dioxide versus deactivation through wiping and irrigation.The efficiency of disinfectant was tested by the device of 099С А4224 manufactured by Glas-Col, USA, using the air sampler of PU-1B, Russia.The Mobile Hygienic Center (MNC, Russia, was used for application of the disinfectant, wiping and irrigation was done using the disperser of Avtomaks AO-2, Russia.The bacterial aerosol was generated in the Glass-Col chamber with the concentration 5 ± 2.5 × 102 CFU/cm3, by spraying the suspension of M. tuberculosis, H37Rv strain. After that, the disinfectant spray was supplied to the chamber, where linoleum objects were placed horizontally on a variety of surfaces. In order to evaluate efficiency of surface treatment by wiping, the test objects were wiped with a tissue, soaked with the solution of Green Dez, based on consumption of 100-150 ml/m2. In 15, 30 and 60 minutes, the samples of inactivated M. tuberculosis aerosol were collected using an aspirator, chambers with test objects were closed and placed in the vent hood. To monitor efficiency of disinfection of the test object surfaces, the rinse blanks were done by wiping the surface with a sterile gauze wad, soaked with 0.5% of sodium thiosulfate solution.The samples of deactivated aerosol and rinse blanks from the surfaces of test objects were put into Petri dishes with Middlebrook 7H11 medium. The cultures were incubated in the thermostat at the temperature of 37 ± 1° C for 10-21 days, and the number of colonies was counted.Sterile water was used

  11. Surface biofunctionalization and production of miniaturized sensor structures using aerosol printing technologies

    International Nuclear Information System (INIS)

    Grunwald, Ingo; Groth, Esther; Wirth, Ingo; Schumacher, Julian; Maiwald, Marcus; Zoellmer, Volker; Busse, Matthias

    2010-01-01

    The work described in this paper demonstrates that very small protein and DNA structures can be applied to various substrates without denaturation using aerosol printing technology. This technology allows high-resolution deposition of various nanoscaled metal and biological suspensions. Before printing, metal and biological suspensions were formulated and then nebulized to form an aerosol which is aerodynamically focused on the printing module of the system in order to achieve precise structuring of the nanoscale material on a substrate. In this way, it is possible to focus the aerosol stream at a distance of about 5 mm from the printhead to the surface. This technology is useful for printing fluorescence-marked proteins and printing enzymes without affecting their biological activity. Furthermore, higher molecular weight DNA can be printed without shearing. The advantages, such as printing on complex, non-planar 3D structured surfaces, and disadvantages of the aerosol printing technology are also discussed and are compared with other printing technologies. In addition, miniaturized sensor structures with line thicknesses in the range of a few micrometers are fabricated by applying a silver sensor structure to glass. After sintering using an integrated laser or in an oven process, electrical conductivity is achieved within the sensor structure. Finally, we printed BSA in small micrometre-sized areas within the sensor structure using the same deposition system. The aerosol printing technology combined with material development offers great advantages for future-oriented applications involving biological surface functionalization on small areas. This is important for innovative biomedical micro-device development and for production solutions which bridge the disciplines of biology and electronics.

  12. Surface biofunctionalization and production of miniaturized sensor structures using aerosol printing technologies.

    Science.gov (United States)

    Grunwald, Ingo; Groth, Esther; Wirth, Ingo; Schumacher, Julian; Maiwald, Marcus; Zoellmer, Volker; Busse, Matthias

    2010-03-01

    The work described in this paper demonstrates that very small protein and DNA structures can be applied to various substrates without denaturation using aerosol printing technology. This technology allows high-resolution deposition of various nanoscaled metal and biological suspensions. Before printing, metal and biological suspensions were formulated and then nebulized to form an aerosol which is aerodynamically focused on the printing module of the system in order to achieve precise structuring of the nanoscale material on a substrate. In this way, it is possible to focus the aerosol stream at a distance of about 5 mm from the printhead to the surface. This technology is useful for printing fluorescence-marked proteins and printing enzymes without affecting their biological activity. Furthermore, higher molecular weight DNA can be printed without shearing. The advantages, such as printing on complex, non-planar 3D structured surfaces, and disadvantages of the aerosol printing technology are also discussed and are compared with other printing technologies. In addition, miniaturized sensor structures with line thicknesses in the range of a few micrometers are fabricated by applying a silver sensor structure to glass. After sintering using an integrated laser or in an oven process, electrical conductivity is achieved within the sensor structure. Finally, we printed BSA in small micrometre-sized areas within the sensor structure using the same deposition system. The aerosol printing technology combined with material development offers great advantages for future-oriented applications involving biological surface functionalization on small areas. This is important for innovative biomedical micro-device development and for production solutions which bridge the disciplines of biology and electronics.

  13. Surface biofunctionalization and production of miniaturized sensor structures using aerosol printing technologies

    Energy Technology Data Exchange (ETDEWEB)

    Grunwald, Ingo; Groth, Esther; Wirth, Ingo; Schumacher, Julian; Maiwald, Marcus; Zoellmer, Volker; Busse, Matthias, E-mail: ingo.wirth@ifam.frauhofer.d [Fraunhofer Institute for Manufacturing Technology and Applied Materials Research (IFAM), Wiener Strasse 12, 28359 Bremen (Germany)

    2010-03-15

    The work described in this paper demonstrates that very small protein and DNA structures can be applied to various substrates without denaturation using aerosol printing technology. This technology allows high-resolution deposition of various nanoscaled metal and biological suspensions. Before printing, metal and biological suspensions were formulated and then nebulized to form an aerosol which is aerodynamically focused on the printing module of the system in order to achieve precise structuring of the nanoscale material on a substrate. In this way, it is possible to focus the aerosol stream at a distance of about 5 mm from the printhead to the surface. This technology is useful for printing fluorescence-marked proteins and printing enzymes without affecting their biological activity. Furthermore, higher molecular weight DNA can be printed without shearing. The advantages, such as printing on complex, non-planar 3D structured surfaces, and disadvantages of the aerosol printing technology are also discussed and are compared with other printing technologies. In addition, miniaturized sensor structures with line thicknesses in the range of a few micrometers are fabricated by applying a silver sensor structure to glass. After sintering using an integrated laser or in an oven process, electrical conductivity is achieved within the sensor structure. Finally, we printed BSA in small micrometre-sized areas within the sensor structure using the same deposition system. The aerosol printing technology combined with material development offers great advantages for future-oriented applications involving biological surface functionalization on small areas. This is important for innovative biomedical micro-device development and for production solutions which bridge the disciplines of biology and electronics.

  14. Effect of surface coating with magnesium stearate via mechanical dry powder coating approach on the aerosol performance of micronized drug powders from dry powder inhalers.

    Science.gov (United States)

    Zhou, Qi Tony; Qu, Li; Gengenbach, Thomas; Larson, Ian; Stewart, Peter J; Morton, David A V

    2013-03-01

    The objective of this study was to investigate the effect of particle surface coating with magnesium stearate on the aerosolization of dry powder inhaler formulations. Micronized salbutamol sulphate as a model drug was dry coated with magnesium stearate using a mechanofusion technique. The coating quality was characterized by X-ray photoelectron spectroscopy. Powder bulk and flow properties were assessed by bulk densities and shear cell measurements. The aerosol performance was studied by laser diffraction and supported by a twin-stage impinger. High degrees of coating coverage were achieved after mechanofusion, as measured by X-ray photoelectron spectroscopy. Concomitant significant increases occurred in powder bulk densities and in aerosol performance after coating. The apparent optimum performance corresponded with using 2% w/w magnesium stearate. In contrast, traditional blending resulted in no significant changes in either bulk or aerosolization behaviour compared to the untreated sample. It is believed that conventional low-shear blending provides insufficient energy levels to expose host micronized particle surfaces from agglomerates and to distribute guest coating material effectively for coating. A simple ultra-high-shear mechanical dry powder coating step was shown as highly effective in producing ultra-thin coatings on micronized powders and to substantially improve the powder aerosolization efficiency.

  15. Field experiments for studying the deposition of aerosols onto vegetation and other surfaces

    International Nuclear Information System (INIS)

    Jonas, R.; Heinemann, K.

    1986-01-01

    For some pollutions, dry deposition clearly predominates in the long-term mean over the wash-out or wet deposition. The deposition velocity or fall-out constant, defined as follows, is a measure of the dry deposition of pollutants onto the soil or vegetation: upsilonsub(g) = K/I, where upsilonsub (g) = deposition velocity (cms -1 ); K = contamination of the sampling surface per cm 2 area (quantity deposited per cm 2 ); I = time-integrated air concentration conventionally measured at a reference height of 1 m above the ground. The deposition velocity of radioactively labelled test aerosols (copper sulphate) onto grass, clover, various species of tree (common beech, hornbeam, red oak, common oak, horse chestnut, silver birch, Norway maple, common spruce, Scots pine, Japanese larch, European larch, common silver fir) as well as onto bare soil, water, metals and horizontal filter paper was determined in an extensive series of field tests at the Julich Nuclear Research Centre (Jonas, 1984; Jonas and Heinemann, 1985). For determination of the deposition velocities, the reader is referred to Jonas and Heinemann (1985). (author)

  16. Measurement of particle size distribution and mass concentration of nuclear fuel aerosols

    International Nuclear Information System (INIS)

    Pickering, S.

    1982-01-01

    The particle size distribution and particle mass concentration of a nuclear fuel aerosol is measured by admitting the aerosol into a vertically-extending container, positioning an alpha particle detector within the container so that its window is horizontal and directed vertically, stopping the admission of aerosol into the container, detecting the alpha-activity of the particles of the aerosol sedimenting onto the detector window (for example in a series of equal time intervals until a constant level is reached), and converting the alpha-activity measurements into particle size distribution and/or particle mass concentration measurements. The detector is attached to a pivotted arm and by raising a counterweight can be lowered from the container for cleaning. (author)

  17. Single particle composition measurements of artificial Calcium Carbonate aerosols

    Science.gov (United States)

    Zorn, S. R.; Mentel, T. F.; Schwinger, T.; Croteau, P. L.; Jayne, J.; Worsnop, D. R.; Trimborn, A.

    2012-12-01

    Mineral dust, with an estimated total source from natural and anthropogenic emissions of up to 2800 Tg/yr, is one of the two largest contributors to total aerosol mass, with only Sea salt having a similar source strength (up to 2600 Tg/yr). The composition of dust particles varies strongly depending on the production process and, most importantly, the source location. Therefore, the composition of single dust particles can be used both to trace source regions of air masses as well as to identify chemical aging processes. Here we present results of laboratory studies on generating artificial calcium carbonate (CaCO3) particles, a model compound for carbonaceous mineral dust particles. Particles were generated by atomizing an aqueous hydrogen carbonate solution. Water was removed using a silica diffusion dryer., then the particles were processed in an oven at temperatures up to 900°C, converting the hydrogen carbonate to its anhydrous form. The resulting aerosol was analyzed using an on-line single particle laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF). The results confirm the conversion to calcium carbonate, and validate that the produced particles indeed can be used as a model compound for carbonaceous dust aerosols.

  18. Real time measurements of submicrometer aerosols in Seoul, Korea: Sources, characteristics, and processing of organic aerosols during winter time.

    Science.gov (United States)

    Kim, H.; Zhang, Q.

    2016-12-01

    Highly time-resolved chemical characterization of non-refractory submicrometer particulate matter (NR-PM1) was conducted in Seoul, the capital of Korea, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The measurements were performed during winter when persistent air quality problems associated with elevated PM concentrations were observed. The average NR-PM1 concentration was 27.5 µg m-3 and the average mass was dominated by organics (44%), followed by nitrate (24%) and sulfate (10%). Five distinct sources of organic aerosol (OA) were identified from positive matrix factorization (PMF) analysis of the AMS data: vehicle emissions represented by a hydrocarbon-like OA factor (HOA), cooking represented by a cooking OA factor (COA), wood combustion represented by a biomass burning OA factor (BBOA), and secondary aerosol formation in the atmosphere that is represented by a semi-volatile oxygenated OA factor (SVOOA) and a low volatile oxygenated OA factor (LVOOA). These factors, on average, contributed 16, 20, 23, 15 and 26% to the total OA mass, respectively, with primary organic aerosol (POA = HOA + COA + BBOA) accounting for 59% of the OA mass. On average, both primary emissions and secondary aerosol formation are important factors affecting air quality in Seoul during winter, contributing approximately equal. However, differences in the fraction of PM source and properties were observed between high and low loading PM period. For example, during stagnant period with low wind speed (WS) (0.99 ± 0.7 m/s) and high RH (71%), high PM loadings (43.6 ± 12.4 µg m-3) with enhanced fractions of nitrate (27%) and SVOOA (8%) were observed, indicating a strong influence from locally generated secondary aerosol. On the other hand, when low PM loadings (12.6 ± 7.1 µg m-3), which were commonly associated with high WS (1.8 ± 1.1 m/s) and low RH (50 %), were observed, the fraction of regional sources, such as sulfate (12%) and LVOOA (21

  19. Comparison of ambient aerosol extinction coefficients obtained from in-situ, MAX-DOAS and LIDAR measurements at Cabauw

    NARCIS (Netherlands)

    Zieger, P.; Weingartner, E.; Henzing, J.; Moerman, M.; Leeuw, G. de; Mikkilä, J.; Ehn, M.; Petäjä, T.; Clémer, K.; Roozendael, M. van; Yilmaz, S.; Frieß, U.; Irie, H.; Wagner, T.; Shaiganfar, R.; Beirle, S.; Apituley, A.; Wilson, K.; Baltensperger, U.

    2011-01-01

    In the field, aerosol in-situ measurements are often performed under dry conditions (relative humidity RH<30-40%). Since ambient aerosol particles experience hygroscopic growth at enhanced RH, their microphysical and optical properties especially the aerosol light scattering are also strongly

  20. Effect of spectrally varying albedo of vegetation surfaces on shortwave radiation fluxes and aerosol direct radiative forcing

    Directory of Open Access Journals (Sweden)

    L. Zhu

    2012-12-01

    Full Text Available This study develops an algorithm for representing detailed spectral features of vegetation albedo based on Moderate Resolution Imaging Spectrometer (MODIS observations at 7 discrete channels, referred to as the MODIS Enhanced Vegetation Albedo (MEVA algorithm. The MEVA algorithm empirically fills spectral gaps around the vegetation red edge near 0.7 μm and vegetation water absorption features at 1.48 and 1.92 μm which cannot be adequately captured by the MODIS 7 channels. We then assess the effects of applying MEVA in comparison to four other traditional approaches to calculate solar fluxes and aerosol direct radiative forcing (DRF at the top of atmosphere (TOA based on the MODIS discrete reflectance bands. By comparing the DRF results obtained through the MEVA method with the results obtained through the other four traditional approaches, we show that filling the spectral gap of the MODIS measurements around 0.7 μm based on the general spectral behavior of healthy green vegetation leads to significant improvement in the instantaneous aerosol DRF at TOA (up to 3.02 W m−2 difference or 48% fraction of the aerosol DRF, −6.28 W m−2, calculated for high spectral resolution surface reflectance from 0.3 to 2.5 μm for deciduous vegetation surface. The corrections of the spectral gaps in the vegetation spectrum in the near infrared, again missed by the MODIS reflectances, also contributes to improving TOA DRF calculations but to a much lower extent (less than 0.27 W m−2, or about 4% of the instantaneous DRF.

    Compared to traditional approaches, MEVA also improves the accuracy of the outgoing solar flux between 0.3 to 2.5 μm at TOA by over 60 W m−2 (for aspen 3 surface and aerosol DRF by over 10 W m−2 (for dry grass. Specifically, for Amazon vegetation types, MEVA can improve the accuracy of daily averaged aerosol radiative forcing in the spectral range of 0.3 to 2.5 μm at

  1. Rapid Measurements of Aerosol Size Distribution and Hygroscopic Growth via Image Processing with a Fast Integrated Mobility Spectrometer (FIMS)

    Science.gov (United States)

    Wang, Y.; Pinterich, T.; Spielman, S. R.; Hering, S. V.; Wang, J.

    2017-12-01

    Aerosol size distribution and hygroscopicity are among key parameters in determining the impact of atmospheric aerosols on global radiation and climate change. In situ submicron aerosol size distribution measurements commonly involve a scanning mobility particle sizer (SMPS). The SMPS scanning time is in the scale of minutes, which is often too slow to capture the variation of aerosol size distribution, such as for aerosols formed via nucleation processes or measurements onboard research aircraft. To solve this problem, a Fast Integrated Mobility Spectrometer (FIMS) based on image processing was developed for rapid measurements of aerosol size distributions from 10 to 500 nm. The FIMS consists of a parallel plate classifier, a condenser, and a CCD detector array. Inside the classifier an electric field separates charged aerosols based on electrical mobilities. Upon exiting the classifier, the aerosols pass through a three stage growth channel (Pinterich et al. 2017; Spielman et al. 2017), where aerosols as small as 7 nm are enlarged to above 1 μm through water or heptanol condensation. Finally, the grown aerosols are illuminated by a laser sheet and imaged onto a CCD array. The images provide both aerosol concentration and position, which directly relate to the aerosol size distribution. By this simultaneous measurement of aerosols with different sizes, the FIMS provides aerosol size spectra nearly 100 times faster than the SMPS. Recent deployment onboard research aircraft demonstrated that the FIMS is capable of measuring aerosol size distributions in 1s (Figure), thereby offering a great advantage in applications requiring high time resolution (Wang et al. 2016). In addition, the coupling of the FIMS with other conventional aerosol instruments provides orders of magnitude more rapid characterization of aerosol optical and microphysical properties. For example, the combination of a differential mobility analyzer, a relative humidity control unit, and a FIMS was

  2. Impact of varying lidar measurement and data processing techniques in evaluating cirrus cloud and aerosol direct radiative effects

    Directory of Open Access Journals (Sweden)

    S. Lolli

    2018-03-01

    Full Text Available In the past 2 decades, ground-based lidar networks have drastically increased in scope and relevance, thanks primarily to the advent of lidar observations from space and their need for validation. Lidar observations of aerosol and cloud geometrical, optical and microphysical atmospheric properties are subsequently used to evaluate their direct radiative effects on climate. However, the retrievals are strongly dependent on the lidar instrument measurement technique and subsequent data processing methodologies. In this paper, we evaluate the discrepancies between the use of Raman and elastic lidar measurement techniques and corresponding data processing methods for two aerosol layers in the free troposphere and for two cirrus clouds with different optical depths. Results show that the different lidar techniques are responsible for discrepancies in the model-derived direct radiative effects for biomass burning (0.05 W m−2 at surface and 0.007 W m−2 at top of the atmosphere and dust aerosol layers (0.7 W m−2 at surface and 0.85 W m−2 at top of the atmosphere. Data processing is further responsible for discrepancies in both thin (0.55 W m−2 at surface and 2.7 W m−2 at top of the atmosphere and opaque (7.7 W m−2 at surface and 11.8 W m−2 at top of the atmosphere cirrus clouds. Direct radiative effect discrepancies can be attributed to the larger variability of the lidar ratio for aerosols (20–150 sr than for clouds (20–35 sr. For this reason, the influence of the applied lidar technique plays a more fundamental role in aerosol monitoring because the lidar ratio must be retrieved with relatively high accuracy. In contrast, for cirrus clouds, with the lidar ratio being much less variable, the data processing is critical because smoothing it modifies the aerosol and cloud vertically resolved extinction profile that is used as input to compute direct radiative effect calculations.

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

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.

    2001-07-01

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

  4. Aerosol particle size distribution in the stratosphere retrieved from SCIAMACHY limb measurements

    Science.gov (United States)

    Malinina, Elizaveta; Rozanov, Alexei; Rozanov, Vladimir; Liebing, Patricia; Bovensmann, Heinrich; Burrows, John P.

    2018-04-01

    health, stratospheric aerosol plays an important role in atmospheric chemistry and climate change. In particular, information about the amount and distribution of stratospheric aerosols is required to initialize climate models, as well as validate aerosol microphysics models and investigate geoengineering. In addition, good knowledge of stratospheric aerosol loading is needed to increase the retrieval accuracy of key trace gases (e.g. ozone or water vapour) when interpreting remote sensing measurements of the scattered solar light. The most commonly used characteristics to describe stratospheric aerosols are the aerosol extinction coefficient and Ångström coefficient. However, the use of particle size distribution parameters along with the aerosol number density is a more optimal approach. In this paper we present a new retrieval algorithm to obtain the particle size distribution of stratospheric aerosol from space-borne observations of the scattered solar light in the limb-viewing geometry. While the mode radius and width of the aerosol particle size distribution are retrieved, the aerosol particle number density profile remains unchanged. The latter is justified by a lower sensitivity of the limb-scattering measurements to changes in this parameter. To our knowledge this is the first data set providing two parameters of the particle size distribution of stratospheric aerosol from space-borne measurements of scattered solar light. Typically, the mode radius and w can be retrieved with an uncertainty of less than 20 %. The algorithm was successfully applied to the tropical region (20° N-20° S) for 10 years (2002-2012) of SCIAMACHY observations in limb-viewing geometry, establishing a unique data set. Analysis of this new climatology for the particle size distribution parameters showed clear increases in the mode radius after the tropical volcanic eruptions, whereas no distinct behaviour of the absolute distribution width could be identified. A tape recorder

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

    Science.gov (United States)

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

    2006-01-01

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

  6. Aerosol optical properties and direct radiative forcing based on measurements from the China Aerosol Remote Sensing Network (CARSNET in eastern China

    Directory of Open Access Journals (Sweden)

    H. Che

    2018-01-01

    Full Text Available Aerosol pollution in eastern China is an unfortunate consequence of the region's rapid economic and industrial growth. Here, sun photometer measurements from seven sites in the Yangtze River Delta (YRD from 2011 to 2015 were used to characterize the climatology of aerosol microphysical and optical properties, calculate direct aerosol radiative forcing (DARF and classify the aerosols based on size and absorption. Bimodal size distributions were found throughout the year, but larger volumes and effective radii of fine-mode particles occurred in June and September due to hygroscopic growth and/or cloud processing. Increases in the fine-mode particles in June and September caused AOD440 nm  >  1.00 at most sites, and annual mean AOD440 nm values of 0.71–0.76 were found at the urban sites and 0.68 at the rural site. Unlike northern China, the AOD440 nm was lower in July and August (∼ 0.40–0.60 than in January and February (0.71–0.89 due to particle dispersion associated with subtropical anticyclones in summer. Low volumes and large bandwidths of both fine-mode and coarse-mode aerosol size distributions occurred in July and August because of biomass burning. Single-scattering albedos at 440 nm (SSA440 nm from 0.91 to 0.94 indicated particles with relatively strong to moderate absorption. Strongly absorbing particles from biomass burning with a significant SSA wavelength dependence were found in July and August at most sites, while coarse particles in March to May were mineral dust. Absorbing aerosols were distributed more or less homogeneously throughout the region with absorption aerosol optical depths at 440 nm  ∼  0.04–0.06, but inter-site differences in the absorption Angström exponent indicate a degree of spatial heterogeneity in particle composition. The annual mean DARF was −93 ± 44 to −79 ± 39 W m−2 at the Earth's surface and ∼ −40 W m−2 at the top of the atmosphere (for

  7. Artifacts in measuring aerosol uptake kinetics: the roles of time, concentration and adsorption

    Directory of Open Access Journals (Sweden)

    L. H. Renbaum

    2011-07-01

    Full Text Available In laboratory studies of organic aerosol particles reacting with gas-phase oxidants, high concentrations of radicals are often used to study on the timescale of seconds reactions which may be occurring over days or weeks in the troposphere. Implicit in this approach is the assumption that radical concentration and time are interchangeable parameters, though this has not been established. Here, the kinetics of OH- and Cl-initiated oxidation reactions of model single-component liquid (squalane and supercooled (brassidic acid and 2-octyldodecanoic acid organic aerosols are studied by varying separately the radical concentration and the reaction time. Two separate flow tubes with residence times of 2 and 66 s are used, and [OH] and [Cl] are varied by adjusting either the laser photolysis fluence or the radical precursor concentration ([O3] or [Cl2], respectively used to generate the radicals. It is found that the rates measured by varying the radical concentration and the reaction time are equal only if the precursor concentrations are the same in the two approaches. Further, the rates depend on the concentrations of the precursor species with a Langmuir-type functional form suggesting that O3 and Cl2 saturate the surface of the liquid particles. It is believed that the presence of O3 inhibits the rate of OH reaction, perhaps by reacting with OH radicals or by O3 or intermediate species blocking surface sites, while Cl2 enhances the rate of Cl reaction by participating in a radical chain mechanism. These results have important implications for laboratory experiments in which high concentrations of gas-phase oxidants are used to study atmospheric reactions over short timescales and may explain the variability in recent measurements of the reactive uptake of OH on squalane particles in reactor systems used in this and other laboratories.

  8. Comparison of Aerosol Classification Results from Airborne High Spectral Resolution Lidar (HSRL) Measurements and the Calipso Vertical Feature Mask

    Science.gov (United States)

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

    2012-01-01

    Knowledge of the vertical profile, composition, concentration, and size of aerosols is required for assessing the direct impact of aerosols on radiation, the indirect effects of aerosols on clouds and precipitation, and attributing these effects to natural and anthropogenic aerosols. Because anthropogenic aerosols are predominantly submicrometer, fine mode fraction (FMF) retrievals from satellite have been used as a tool for deriving anthropogenic aerosols. Although column and profile satellite retrievals of FMF have been performed over the ocean, such retrievals have not yet been been done over land. Consequently, uncertainty in satellite estimates of the anthropogenic component of the aerosol direct radiative forcing is greatest over land, due in large part to uncertainties in the FMF. Satellite measurements have been used to detect and evaluate aerosol impacts on clouds; however, such efforts have been hampered by the difficulty in retrieving vertically-resolved cloud condensation nuclei (CCN) concentration, which is the most direct parameter linking aerosol and clouds. Recent studies have shown correlations between average satellite derived column aerosol optical thickness (AOT) and in situ measured CCN. However, these same studies, as well as others that use detailed airborne in situ measurements have noted that vertical variability of the aerosol distribution, impacts of relative humidity, and the presence of coarse mode aerosols such as dust introduce large uncertainties in such relations.

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

    Science.gov (United States)

    Ismail, Syed; Ferrare, Richard A.; Browell, Edward V.; Kooi, Susan A.; Dunion, Jason P.; Heymsfield, Gerry; Notari, Anthony; Butler, Carolyn F.; Burton, Sharon; Fenn, Marta; hide

    2010-01-01

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

  10. Measurements of the effect of humidity on radio-aerosol penetration through ultrafine capillaries

    International Nuclear Information System (INIS)

    Cullen, C.

    1996-08-01

    The purpose of this research was to examine the effects of humidity on radio-aerosol penetration through ultrafine capillaries. A number of tests were conducted at relative humidities of 20%, 50%, and 80%, with sampling times of 20, 40, and 60 min. The radio-aerosol consisted of polystyrene particles with a diameter of 0.1 microm. The ultrafine capillaries had a diameter of 250 microm. The data from these tests varied significantly. These results made the identification of radio-aerosol penetration trends inconclusive. The standard deviation for all penetration data ranged from 3% to 30%. The results of this study suggest that a better control of the experimental parameters was needed to obtain more accurate data from experiments associated with radio-aerosol penetration in the presence of moisture. The experimental parameters that may have contributed to the wide variance of data, include aerosol flow, radio-aerosol generation, capillary characteristics, humidity control, and radiation measurements. It was the uncertainty of these parameters that contributed to the poor data which made conclusive deductions about radio-aerosol penetration dependence on humidity difficult. The application of this study is to ultrafine leaks resulting from stress fractures in high-level nuclear waste transportation casks under accident scenarios

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

    International Nuclear Information System (INIS)

    Mccormick, M.P.

    1985-10-01

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

  12. Meteorological and Land Surface Properties Impacting Sea Breeze Extent and Aerosol Distribution in a Dry Environment

    Science.gov (United States)

    Igel, Adele L.; van den Heever, Susan C.; Johnson, Jill S.

    2018-01-01

    The properties of sea breeze circulations are influenced by a variety of meteorological and geophysical factors that interact with one another. These circulations can redistribute aerosol particles and pollution and therefore can play an important role in local air quality, as well as impact remote sensing. In this study, we select 11 factors that have the potential to impact either the sea breeze circulation properties and/or the spatial distribution of aerosols. Simulations are run to identify which of the 11 factors have the largest influence on the sea breeze properties and aerosol concentrations and to subsequently understand the mean response of these variables to the selected factors. All simulations are designed to be representative of conditions in coastal sub tropical environments and are thus relatively dry, as such they do not support deep convection associated with the sea breeze front. For this dry sea breeze regime, we find that the background wind speed was the most influential factor for the sea breeze propagation, with the soil saturation fraction also being important. For the spatial aerosol distribution, the most important factors were the soil moisture, sea-air temperature difference, and the initial boundary layer height. The importance of these factors seems to be strongly tied to the development of the surface-based mixed layer both ahead of and behind the sea breeze front. This study highlights potential avenues for further research regarding sea breeze dynamics and the impact of sea breeze circulations on pollution dispersion and remote sensing algorithms.

  13. Discharge current measurements on Venera 13 & 14 - Evidence for charged aerosols in the Venus lower atmosphere?

    Science.gov (United States)

    Lorenz, Ralph D.

    2018-06-01

    Measurements of discharge currents on the Venera 13 and 14 landers during their descent in the lowest 35 km of the Venus atmosphere are interpreted as driven either by an ambient electric field, or by deposition of charge from aerosols. The latter hypothesis is favored (`triboelectric charging' in aeronautical parlance), and would entail an aerosol opacity and charge density somewhat higher than that observed in Saharan dust transported over long distances on Earth.

  14. Development of a 10 Hz measurement system for atmospheric aerosol concentration

    International Nuclear Information System (INIS)

    Bouarouri, Assia

    2014-01-01

    The goal is to develop an aerosol charger based on a corona discharge for atmospheric concentration measurements (10 3 -10 5 cm -3 ) within a response time of 100 ms. Two ion sources, point-to-hole and wire-to-slit have been characterized. The increase of the ion flow in the post-discharge by EHD ion confinement in both the discharge gap and the hole has been shown. At first, using an experimental survey driven in two mixing configurations, concentric and face-to-face, we have confirmed the aerosol diffusion charging law which depends on aerosol diameter and N i .t product, with N i , the ions concentration and t, the charging time. Thus, the originality of this charger relies on the very high heterogeneity of unipolar ion densities (N i 0 ≥10 9 cm -3 ) required to compensate the charging time of 50 ms. In these conditions, we have shown that aerosol diameter and the charging dynamic (which depends also on the diameter) control the aerosol trajectory. The chargers have, next, been compared in different operating conditions, mainly in terms of the maximal charging and the minimal losses. In the chosen charger (point-to-hole ion source and concentric mixing), the relations charge/mobility and losses according to diameter have been characterized. We have also shown the linearity of the charged particles current with the aerosol concentration which allows the current-concentration data inversion. The preliminary measurement system composed by the charger, the separator and the particle current measurements, satisfies the objectives of the study in terms of the concentration detection limit (10 3 cm -3 ) and the response time (100 ms). We have thus shown the feasibility of an atmospheric aerosol concentration measurement system at 10 Hz using a corona discharge charger provided that the separation power is improved. Furthermore, knowing that aerosol losses are negligible and the lower limit of the partial charging, the developed charger is adaptable with other

  15. Evaluation of operational forecast model of aerosol transportation using ceilometer network measurements

    Science.gov (United States)

    Chan, Ka Lok; Wiegner, Matthias; Flentje, Harald; Mattis, Ina; Wagner, Frank; Gasteiger, Josef; Geiß, Alexander

    2017-04-01

    Due to technical improvements of ceilometers in recent years, ceilometer measurements are not only limited to determine cloud base heights but also providing information on the vertical aerosol distribution. Therefore, several national weather services implemented ceilometer networks. These measurements are e.g. valuable for the evaluation of the chemical transport model simulations. In this study, we present comparisons of European Centre for Medium-Range Weather Forecast Integrated Forecast System (ECMWF-IFS) model simulation of aerosol backscatter coefficients with ceilometer network measurements operated by the German weather service (DWD) . Five different types of aerosol are available in the model simulations which include two natural aerosols, sea salt and dust. The other three aerosol types, i.e. sulfate, organic carbon and black carbon, have significant anthropogenic contributions. As the model output provides mass mixing ratios of the above mentioned types of aerosol and the ceilometers measure attenuated backscatter (β∗) provided that calibration took place, it is necessary to determine a common physical quantity for the comparison. We have chosen the aerosol backscatter coefficient (β) for this purpose. The β-profiles are calculated from the mass mixing ratios of the model output assuming the inherent aerosol microphysics properties. It shall be emphasized that in the model calculations, all particles are assumed to be spherical. We have examined the sensitivity of the intercomparison on the hygroscopic growth of particles and on the role of particle shape. Our results show that the hygroscopic growth of particle is crucial (up to a factor of 22) in converting the model output to backscatter coefficient profiles whereas the effect of non-sphericity of dust particles is comparably small (˜44%). Furthermore, the calibration of the ceilometer signals can be an issue. The agreements between modeled and retrieved β-profiles show different

  16. Tethered balloon operation for wintering aerosol measurements in the lower troposphere at Syowa Station, Antarctica

    Directory of Open Access Journals (Sweden)

    Keiichiro Hara

    2007-03-01

    Full Text Available The 46th Japanese Antarctic Research Expedition (JARE-46 carried out twenty seven tethered-balloon-borne aerosol measurements at Syowa Station for better understanding of aerosol chemical and physical properties in the lower troposphere from 6th January 2005 until 11 December 2005. This report summarizes the plan, preparation, field activities and some troubles/problems in the tethered-balloon observations.

  17. Identification of long-range transport of aerosols over Austria using EARLINET lidar measurements

    Science.gov (United States)

    Camelia, Talianu

    2018-04-01

    The aims of the study is to identify the paths of the long-range transported aerosols over Austria and their potential origin, and to estimate their properties, using lidar measurements from EARLINET stations closest to Austria from Germany and Romania and aerosol transport models. As of now, there is no lidar station in Austria. The study is part of a project to estimate the usefulness of a lidar station located in Vienna, Austria.

  18. Apportionment of urban aerosol sources in Cork (Ireland) by synergistic measurement techniques.

    Science.gov (United States)

    Dall'Osto, Manuel; Hellebust, Stig; Healy, Robert M; O'Connor, Ian P; Kourtchev, Ivan; Sodeau, John R; Ovadnevaite, Jurgita; Ceburnis, Darius; O'Dowd, Colin D; Wenger, John C

    2014-09-15

    The sources of ambient fine particulate matter (PM2.5) during wintertime at a background urban location in Cork city (Ireland) have been determined. Aerosol chemical analyses were performed by multiple techniques including on-line high resolution aerosol time-of-flight mass spectrometry (Aerodyne HR-ToF-AMS), on-line single particle aerosol time-of-flight mass spectrometry (TSI ATOFMS), on-line elemental carbon-organic carbon analysis (Sunset_EC-OC), and off-line gas chromatography/mass spectrometry and ion chromatography analysis of filter samples collected at 6-h resolution. Positive matrix factorization (PMF) has been carried out to better elucidate aerosol sources not clearly identified when analyzing results from individual aerosol techniques on their own. Two datasets have been considered: on-line measurements averaged over 2-h periods, and both on-line and off-line measurements averaged over 6-h periods. Five aerosol sources were identified by PMF in both datasets, with excellent agreement between the two solutions: (1) regional domestic solid fuel burning--"DSF_Regional," 24-27%; (2) local urban domestic solid fuel burning--"DSF_Urban," 22-23%; (3) road vehicle emissions--"Traffic," 15-20%; (4) secondary aerosols from regional anthropogenic sources--"SA_Regional" 9-13%; and (5) secondary aged/processed aerosols related to urban anthropogenic sources--"SA_Urban," 21-26%. The results indicate that, despite regulations for restricting the use of smoky fuels, solid fuel burning is the major source (46-50%) of PM2.5 in wintertime in Cork, and also likely other areas of Ireland. Whilst wood combustion is strongly associated with OC and EC, it was found that peat and coal combustion is linked mainly with OC and the aerosol from these latter sources appears to be more volatile than that produced by wood combustion. Ship emissions from the nearby port were found to be mixed with the SA_Regional factor. The PMF analysis allowed us to link the AMS cooking organic

  19. Effect of surface albedo, water vapour, and atmospheric aerosols on the cloud-free shortwave radiative budget in the Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Di Biagio, C. [ENEA, Laboratory for Earth Observations and Analyses, Rome (Italy); University of Siena, Department of Earth Science, Siena (Italy); Di Sarra, A. [ENEA, Laboratory for Earth Observations and Analyses, Rome (Italy); Eriksen, P. [Danish Climate Centre, DMI, Danish Meteorological Institute, Copenhagen (Denmark); Ascanius, S.E. [DMI, Danish Meteorological Institute, Qaanaaq (Greenland); Muscari, G. [INGV, Istituto Nazionale di Geofisica e Vulcanologia, Rome (Italy); Holben, B. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)

    2012-08-15

    This study is based on ground-based measurements of downward surface shortwave irradiance (SW), columnar water vapour (wv), and aerosol optical depth ({tau}) obtained at Thule Air Base (Greenland) in 2007-2010, together with MODIS observations of the surface shortwave albedo (A). Radiative transfer model calculations are used in combination with measurements to separate the radiative effect of A ({Delta}SW{sub A}), wv ({Delta}SW{sub wv}), and aerosols ({Delta}SW{sub {tau}}) in modulating SW in cloud-free conditions. The shortwave radiation at the surface is mainly affected by water vapour absorption, which produces a reduction of SW as low as -100 Wm{sup -2} (-18%). The seasonal change of A produces an increase of SW by up to +25 Wm{sup -2} (+4.5%). The annual mean radiative effect is estimated to be -(21-22) Wm{sup -2} for wv, and +(2-3) Wm{sup -2} for A. An increase by +0.065 cm in the annual mean wv, to which corresponds an absolute increase in {Delta}SW{sub wv} by 0.93 Wm{sup -2} (4.3%), has been observed to occur between 2007 and 2010. In the same period, the annual mean A has decreased by -0.027, with a corresponding decrease in {Delta}SW{sub A} by 0.41 Wm{sup -2} (-14.9%). Atmospheric aerosols produce a reduction of SW as low as -32 Wm{sup -2} (-6.7%). The instantaneous aerosol radiative forcing (RF{sub {tau}}) reaches values of -28 Wm{sup -2} and shows a strong dependency on surface albedo. The derived radiative forcing efficiency (FE{sub {tau}}) for solar zenith angles between 55 and 70 is estimated to be (-120.6 {+-} 4.3) for 0.1 < A < 0.2, and (-41.2 {+-} 1.6) Wm{sup -2} for 0.5 < A < 0.6. (orig.)

  20. Interpretation of DIAL Measurements of Lower Stratospheric Ozone in Regions with Pinatubo Aerosols

    Science.gov (United States)

    Grant, William B.; Browell, Edward V.; Fenn, Marta A.; Butler, Carolyn F.; Brackett, Vincent G.; Veiga, Robert E.; Mayor, Shane D.; Fishman, Jack; Nganga, D.; Minga, A.

    1992-01-01

    The influence of volcanic aerosols on stratospheric ozone is a topic of current interest, especially with the June 15, 1991 eruption of Mt. Pinatubo in the Philippines. Lidar has been used in the past to provide aerosol profiles which could be compared with ozone profiles measured using ozonesondes to look for coincidences between volcanic aerosols and ozone decreases. The differential absorption lidar (DIAL) technique has the advantages of being able to measure ozone and aerosol profiles simultaneously as well as being able to cover large geographical regions rapidly. While there are problems associated with correcting the ozone profiles for the presence of aerosols, the corrections can be made reliably when the wavelengths are closely spaced and the Bernoulli method is applied. The DIAL measurements considered in this paper are those obtained in the tropical stratosphere in January 1992 during the Airborne Arctic Stratospheric Expedition (AASE-II). The determination of ozone profiles in the presence of Pinatubo aerosols is discussed in a companion paper.

  1. Validation of high-resolution aerosol optical thickness simulated by a global non-hydrostatic model against remote sensing measurements

    Science.gov (United States)

    Goto, Daisuke; Sato, Yousuke; Yashiro, Hisashi; Suzuki, Kentaroh; Nakajima, Teruyuki

    2017-02-01

    A high-performance computing resource allows us to conduct numerical simulations with a horizontal grid spacing that is sufficiently high to resolve cloud systems. The cutting-edge computational capability, which was provided by the K computer at RIKEN in Japan, enabled the authors to perform long-term, global simulations of air pollutions and clouds with unprecedentedly high horizontal resolutions. In this study, a next generation model capable of simulating global air pollutions with O(10 km) grid spacing by coupling an atmospheric chemistry model to the Non-hydrostatic Icosahedral Atmospheric Model (NICAM) was performed. Using the newly developed model, month-long simulations for July were conducted with 14 km grid spacing on the K computer. Regarding the global distributions of aerosol optical thickness (AOT), it was found that the correlation coefficient (CC) between the simulation and AERONET measurements was approximately 0.7, and the normalized mean bias was -10%. The simulated AOT was also compared with satellite-retrieved values; the CC was approximately 0.6. The radiative effects due to each chemical species (dust, sea salt, organics, and sulfate) were also calculated and compared with multiple measurements. As a result, the simulated fluxes of upward shortwave radiation at the top of atmosphere and the surface compared well with the observed values, whereas those of downward shortwave radiation at the surface were underestimated, even if all aerosol components were considered. However, the aerosol radiative effects on the downward shortwave flux at the surface were found to be as high as 10 W/m2 in a global scale; thus, simulated aerosol distributions can strongly affect the simulated air temperature and dynamic circulation.

  2. Surface flow measurements from drones

    Science.gov (United States)

    Tauro, Flavia; Porfiri, Maurizio; Grimaldi, Salvatore

    2016-09-01

    Drones are transforming the way we sense and interact with the environment. However, despite their increased capabilities, the use of drones in geophysical sciences usually focuses on image acquisition for generating high-resolution maps. Motivated by the increasing demand for innovative and high performance geophysical observational methodologies, we posit the integration of drone technology and optical sensing toward a quantitative characterization of surface flow phenomena. We demonstrate that a recreational drone can be used to yield accurate surface flow maps of sub-meter water bodies. Specifically, drone's vibrations do not hinder surface flow observations, and velocity measurements are in agreement with traditional techniques. This first instance of quantitative water flow sensing from a flying drone paves the way to novel observations of the environment.

  3. The Measurement of Aerosol Optical Properties Using Continuous Wave Cavity Ring-Down Techniques

    Science.gov (United States)

    Strawa, A. W.; Owano, T.; Castaneda, R.; Baer, D. S.; Paldus, B. A.; Gore, Warren J. (Technical Monitor)

    2002-01-01

    Large uncertainties in the effects that aerosols have on climate require improved in-situ measurements of extinction coefficient and single-scattering albedo. This abstract describes the use of continuous wave cavity ring-down (CW-CRD) technology to address this problem. The innovations in this instrument are the use of CW-CRD to measure aerosol extinction coefficient, the simultaneous measurement of scattering coefficient, and small size suitable for a wide range of aircraft applications. Our prototype instrument measures extinction and scattering coefficient at 690 nm and extinction coefficient at 1550 nm. The instrument itself is small (60 x 48 x 15 cm) and relatively insensitive to vibrations. The prototype instrument has been tested in our lab and used in the field. While improvements in performance are needed, the prototype has been shown to make accurate and sensitive measurements of extinction and scattering coefficients. Combining these two parameters, one can obtain the single-scattering albedo and absorption coefficient, both important aerosol properties. The use of two wavelengths also allows us to obtain a quantitative idea of the size of the aerosol through the Angstrom exponent. Minimum sensitivity of the prototype instrument is 1.5 x 10(exp -6)/m (1.5/Mm). Validation of the measurement of extinction coefficient has been accomplished by comparing the measurement of calibration spheres with Mie calculations. This instrument and its successors have potential to help reduce uncertainty currently associated with aerosol optical properties and their spatial and temporal variation. Possible applications include studies of visibility, climate forcing by aerosol, and the validation of aerosol retrieval schemes from satellite data.

  4. Mobile LiDAR Measurement for Aerosol Investigation in South-Central Hebei, China

    Science.gov (United States)

    qin, kai; Wu, Lixin; Zheng, Yunhui; Wong Man, Sing; Wang, Runfeng; Hu, Mingyu; Lang, Hongmei; Wang, Luyao; Bai, Yang; Rao, Lanlan

    2016-04-01

    With the rapid industrialization and urbanization in China during the last decades, the increasing anthropogenic pollutant emissions have significantly caused serious air pollution problems which are adversely influencing public health. Hebei is one of the most air polluted provinces in China. In January 2013, an extremely severe and persistent haze episode with record-breaking PM2.5 outbreak affecting hundreds of millions of people occurred over eastern and northern China. During that haze episode, 7 of the top 10 most polluted cities in China were located in the Hebei Province according to the report of China's Ministry of Environmental Protection. To investigate and the spatial difference and to characterize the vertical distribution of aerosol in different regions of south-central Hebei, mobile measurements were carried out using a mini micro pulse LiDAR system (model: MiniMPL) in March 2014. The mobile LiDAR kit consisting of a MiniMPL, a vibration reduction mount, a power inverter, a Windows surface tablet and a GPS receiver were mounted in a car watching though the sunroof opening. For comparison, a fixed measurement using a traditional micro pulse LiDAR system (model: MPL-4B) was conducted simultaneously in Shijiazhuang, the capital of Hebei Province. The equipped car was driven from downtown Shijiazhuang by way of suburban and rural area to downtown Cangzhou, Handan, and Baoding respectively at almost stable speed around 100Km per hour along different routes which counted in total more than 1000Km. The results can be summarized as: 1) the spatial distribution of total aerosol optical depth along the measurement routes in south-central Hebei was controlled by local terrain and population in general, with high values in downtown and suburban in the plain areas, and low values in rural areas along Taihang mountain to the west and Yan mountain to the north; 2) obviously high AODs were obtained at roads crossing points, inside densely populated area and nearby

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

    Directory of Open Access Journals (Sweden)

    M. Pikridas

    2010-07-01

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

  6. Atmospheric effect on the ground-based measurements of broadband surface albedo

    Directory of Open Access Journals (Sweden)

    T. Manninen

    2012-11-01

    Full Text Available Ground-based pyranometer measurements of the (clear-sky broadband surface albedo are affected by the atmospheric conditions (mainly by aerosol particles, water vapour and ozone. A new semi-empirical method for estimating the magnitude of the effect of atmospheric conditions on surface albedo measurements in clear-sky conditions is presented. Global and reflected radiation and/or aerosol optical depth (AOD at two wavelengths are needed to apply the method. Depending on the aerosol optical depth and the solar zenith angle values, the effect can be as large as 20%. For the cases we tested using data from the Cabauw atmospheric test site in the Netherlands, the atmosphere caused typically up to 5% overestimation of surface albedo with respect to corresponding black-sky surface albedo values.

  7. Method of measuring surface density

    International Nuclear Information System (INIS)

    Gregor, J.

    1982-01-01

    A method is described of measuring surface density or thickness, preferably of coating layers, using radiation emitted by a suitable radionuclide, e.g., 241 Am. The radiation impinges on the measured material, e.g., a copper foil and in dependence on its surface density or thickness part of the flux of impinging radiation is reflected and part penetrates through the material. The radiation which has penetrated through the material excites in a replaceable adjustable backing characteristic radiation of an energy close to that of the impinging radiation (within +-30 keV). Part of the flux of the characteristic radiation spreads back to the detector, penetrates through the material in which in dependence on surface density or thickness of the coating layer it is partly absorbed. The flux of the penetrated characteristic radiation impinging on the face of the detector is a function of surface density or thickness. Only that part of the energy is evaluated of the energy spectrum which corresponds to the energy of characteristic radiation. (B.S.)

  8. Optical measurements on contaminated surfaces

    Science.gov (United States)

    Bonham, T. E.; Schmitt, R. J.; Linford, R. M. F.

    1975-01-01

    A bidirectional reflectometer system was developed for in situ measurements of the changes in spectral reflectance of surfaces contaminated with films of organic materials. The system permits experiments with films of controlled thickness in an environment that simulates the thermal, radiation, and vacuum conditions of space. The mechanical and optical construction of the reflectometer are discussed in detail, and actual data curves are used to illustrate its operation and performance.

  9. Underground measurements of aerosol in radon and thoron progeny activity distributions

    International Nuclear Information System (INIS)

    Khan, A.; Bandi, F.; Phillips, C.R.; Duport, P.

    1990-01-01

    Aerosol and activity distributions of 218 Polonium, 214 Lead, 214 Bismuth, and 212 Lead were determined in two different underground mining environments by means of an optimized time-delay counting scheme and diffusion batteries. In one environment, diesel equipment was operating; and in the other, electrically powered equipment. The two environments differed significantly in total aerosol concentration. In the diesel environment, in particular, aerosol concentrations were unsteady, and fluctuated with vehicular traffic and mining activities. As measured by radon progeny disequilibrium, the age of the air ranged from about 25 to 60 minutes. Thoron working levels were of the same order as radon working levels. In this paper, comparisons are made between the aerosol and activity size distributions in both the diesel and electric mine

  10. Volatility measurement of atmospheric submicron aerosols in an urban atmosphere in southern China

    Science.gov (United States)

    Cao, Li-Ming; Huang, Xiao-Feng; Li, Yuan-Yuan; Hu, Min; He, Ling-Yan

    2018-02-01

    Aerosol pollution has been a very serious environmental problem in China for many years. The volatility of aerosols can affect the distribution of compounds in the gas and aerosol phases, the atmospheric fates of the corresponding components, and the measurement of the concentration of aerosols. Compared to the characterization of chemical composition, few studies have focused on the volatility of aerosols in China. In this study, a thermodenuder aerosol mass spectrometer (TD-AMS) system was deployed to study the volatility of non-refractory submicron particulate matter (PM1) species during winter in Shenzhen. To our knowledge, this paper is the first report of the volatilities of aerosol chemical components based on a TD-AMS system in China. The average PM1 mass concentration during the experiment was 42.7±20.1 µg m-3, with organic aerosol (OA) being the most abundant component (43.2 % of the total mass). The volatility of chemical species measured by the AMS varied, with nitrate showing the highest volatility, with a mass fraction remaining (MFR) of 0.57 at 50 °C. Organics showed semi-volatile characteristics (the MFR was 0.88 at 50 °C), and the volatility had a relatively linear correlation with the TD temperature (from the ambient temperature to 200 °C), with an evaporation rate of 0.45 % °C-1. Five subtypes of OA were resolved from total OA using positive matrix factorization (PMF) for data obtained under both ambient temperature and high temperatures through the TD, including a hydrocarbon-like OA (HOA, accounting for 13.5 %), a cooking OA (COA, 20.6 %), a biomass-burning OA (BBOA, 8.9 %), and two oxygenated OAs (OOAs): a less-oxidized OOA (LO-OOA, 39.1 %) and a more-oxidized OOA (MO-OOA, 17.9 %). Different OA factors presented different volatilities, and the volatility sequence of the OA factors at 50 °C was HOA (MFR of 0.56) > LO-OOA (0.70) > COA (0.85) ≈ BBOA (0.87) > MO-OOA (0.99), which was not completely consistent with the sequence of their O

  11. IN SITU MEASUREMENTS OF THE SIZE AND DENSITY OF TITAN AEROSOL ANALOGS

    Energy Technology Data Exchange (ETDEWEB)

    Hoerst, S. M.; Tolbert, M. A, E-mail: sarah.horst@colorado.edu [Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO (United States)

    2013-06-10

    The organic haze produced from complex CH{sub 4}/N{sub 2} chemistry in the atmosphere of Titan plays an important role in processes that occur in the atmosphere and on its surface. The haze particles act as condensation nuclei and are therefore involved in Titan's methane hydrological cycle. They also may behave like sediment on Titan's surface and participate in both fluvial and aeolian processes. Models that seek to understand these processes require information about the physical properties of the particles including their size and density. Although measurements obtained by Cassini-Huygens have placed constraints on the size of the haze particles, their densities remain unknown. We have conducted a series of Titan atmosphere simulation experiments and measured the size, number density, and particle density of Titan aerosol analogs, or tholins, for CH{sub 4} concentrations from 0.01% to 10% using two different energy sources, spark discharge and UV. We find that the densities currently in use by many Titan models are higher than the measured densities of our tholins.

  12. IN SITU MEASUREMENTS OF THE SIZE AND DENSITY OF TITAN AEROSOL ANALOGS

    International Nuclear Information System (INIS)

    Hörst, S. M.; Tolbert, M. A

    2013-01-01

    The organic haze produced from complex CH 4 /N 2 chemistry in the atmosphere of Titan plays an important role in processes that occur in the atmosphere and on its surface. The haze particles act as condensation nuclei and are therefore involved in Titan's methane hydrological cycle. They also may behave like sediment on Titan's surface and participate in both fluvial and aeolian processes. Models that seek to understand these processes require information about the physical properties of the particles including their size and density. Although measurements obtained by Cassini-Huygens have placed constraints on the size of the haze particles, their densities remain unknown. We have conducted a series of Titan atmosphere simulation experiments and measured the size, number density, and particle density of Titan aerosol analogs, or tholins, for CH 4 concentrations from 0.01% to 10% using two different energy sources, spark discharge and UV. We find that the densities currently in use by many Titan models are higher than the measured densities of our tholins.

  13. Measurements of stratospheric Pinatubo aerosol extinction profiles by a Raman lidar

    International Nuclear Information System (INIS)

    Abo, Makoto; Nagasawa, Chikao.

    1992-01-01

    The Raman lidar has been used for remote measurements of water vapor, ozone and atmospheric temperature in the lower troposphere because the Raman cross section is three orders smaller than the Rayleigh cross section. The authors estimated the extinction coefficients of the Pinatubo volcanic aerosol in the stratosphere using a Raman lidar. If the precise aerosol extinction coefficients are derived, the backscatter coefficient of a Mie scattering lidar will be more accurately estimated. The Raman lidar has performed to measure density profiles of some species using Raman scattering. Here the authors used a frequency-doubled Nd:YAG laser for transmitter and received nitrogen vibrational Q-branch Raman scattering signal. Ansmann et al. (1990) derived tropospherical aerosol extinction profiles with a Raman lidar. The authors think that this method can apply to dense stratospheric aerosols such as Pinatubo volcanic aerosols. As dense aerosols are now accumulated in the stratosphere by Pinatubo volcanic eruption, the error of Ramen lidar signal regarding the fluctuation of air density can be ignored

  14. The Asian Tropopause Aerosol Layer: Balloon-Borne Measurements, Satellite Observations and Modeling Approaches

    Science.gov (United States)

    Fairlie, T. D.; Vernier, J.-P.; Natarajan, M.; Deshler, Terry; Liu, H.; Wegner, T.; Baker, N.; Gadhavi, H.; Jayaraman, A.; Pandit, A.; hide

    2016-01-01

    Satellite observations and numerical modeling studies have demonstrated that the Asian Summer Monsoon (ASM) can 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 associated with ASM anticyclone, in the upper troposphere and lower stratosphere (UTLS). 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 instrumentation, aircraft and satellite observations, combined 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-based observations from our BATAL-2015 field campaign to India and Saudi Arabia in summer 2015, including in situ backscatter measurements from COBALD instruments, and some of 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 contributions to the ATAL, which is supported by simulations using the GEOS-Chem CTM. Source elimination studies conducted with the GEOS-Chem indicate that 80-90% of ATAL aerosols originate from south Asian sources, in contrast with some earlier studies.

  15. Measurement and analysis of the concentration and size distribution of aerosols in a copper mine

    International Nuclear Information System (INIS)

    Li Dehong; Zhuo Weihai; Huang Gang; Su Xu; Sun Quanfu

    2008-01-01

    Objective: To explore the general characteristics of the concentration and size distribution of aerosols in a mine. Methods: In different areas of a non-uranium mine, the particle number and mass concentration of aerosols were surveyed with a condensation particle counter and a personal aerosol monitor, respectively, and the size distribution of aerosols larger than 1 μm in size was estimated according to the size- selective measurements of mass concentrations. The size distribution of submicron aerosols was evaluated based on the method of screen diffusion battery (SOB), and the measurements were performed in both inside and outside of a control room. Results: The mass concentration of inhaled particles (PM10) was averaged to be 0.42 mg/m 3 in the whole mine, and it varied with different working areas and significantly affected with human activities. In the mine, particles lager than 1 μm in size widely distributed, while the particles less than 5 nm in size were seldom observed. Conclusions: The characteristics of aerosol significantly change with different working areas, human activities and Antilation condition in mine. The dose contribution from inhaled radioactive particles larger than 1 μm in size should be considered in mine. (authors)

  16. Modelling and measurements of urban aerosol processes on the neighborhood scale in Rotterdam, Oslo and Helsinki

    Science.gov (United States)

    Karl, M.; Kukkonen, J.; Keuken, M. P.; Lützenkirchen, S.; Pirjola, L.; Hussein, T.

    2015-12-01

    This study evaluates the influence of aerosol processes on the particle number (PN) concentrations in three major European cities on the temporal scale of one hour, i.e. on the neighborhood and city scales. We have used selected measured data of particle size distributions from previous campaigns in the cities of Helsinki, Oslo and Rotterdam. The aerosol transformation processes were evaluated using an aerosol dynamics model MAFOR, combined with a simplified treatment of roadside and urban atmospheric dispersion. We have compared the model predictions of particle number size distributions with the measured data, and conducted sensitivity analyses regarding the influence of various model input variables. We also present a simplified parameterization for aerosol processes, which is based on the more complex aerosol process computations; this simple model can easily be implemented to both Gaussian and Eulerian urban dispersion models. Aerosol processes considered in this study were (i) the coagulation of particles, (ii) the condensation and evaporation of n-alkanes, and (iii) dry deposition. The chemical transformation of gas-phase compounds was not taken into account. It was not necessary to model the nucleation of gas-phase vapors, as the computations were started with roadside conditions. Dry deposition and coagulation of particles were identified to be the most important aerosol dynamic processes that control the evolution and removal of particles. The effect of condensation and evaporation of organic vapors emitted by vehicles on particle numbers and on particle size distributions was examined. Under inefficient dispersion conditions, condensational growth contributed significantly to the evolution of PN from roadside to the neighborhood scale. The simplified parameterization of aerosol processes can predict particle number concentrations between roadside and the urban background with an inaccuracy of ∼ 10 %, compared to the fully size-resolved MAFOR model.

  17. Chemical data assimilation of geostationary aerosol optical depth and PM surface observations on regional aerosol modeling over the Korean Peninsula during KORUS-AQ campaign

    Science.gov (United States)

    Jung, J.; Choi, Y.; Souri, A.; Jeon, W.

    2017-12-01

    Particle matter(PM) has played a significantly deleterious role in affecting human health and climate. Recently, continuous high concentrations of PM in Korea attracted public attention to this critical issue, and the Korea-United States Air Quality Study(KORUS-AQ) campaign in 2016 was conducted to investigate the causes. For this study, we adjusted the initial conditions in the chemical transport model(CTM) to improve its performance over Korean Peninsula during KORUS-AQ period, using the campaign data to evaluate our model performance. We used the Optimal Interpolation(OI) approach and used hourly surface air quality measurement data from the Air Quality Monitoring Station(AQMS) by NIER and the aerosol optical depth(AOD) measured by a GOCI sensor from the geostationary orbit onboard the Communication Ocean and Meteorological Satellite(COMS). The AOD at 550nm has a 6km spatial resolution and broad coverage over East Asia. After assimilating the surface air quality observation data, the model accuracy significantly improved compared to base model result (without assimilation). It reported very high correlation value (0.98) and considerably decreased mean bias. Especially, it well captured some high peaks which was underpredicted by the base model. To assimilate satellite data, we applied AOD scaling factors to quantify each specie's contribution to total PM concentration and find-mode fraction(FMF) to define vertical distribution. Finally, the improvement showed fairly good agreement.

  18. Tropospheric Aerosols

    Science.gov (United States)

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

    2003-12-01

    m, PM10=1.1 μg m-3; estimated coefficient of light scattering by particulate matter, σep, at 570 nm=12 Mm-1). (b) High aerosol concentration (PM2.5=43.9 μg m-3; PM10=83.4 μg m-3; estimated σep at 570 nm=245 Mm-1) (reproduced by permission of National Park Service, 2002). Although comprising only a small fraction of the mass of Earth's atmosphere, aerosol particles are highly important constituents of the atmosphere. Special interest has focused on aerosols in the troposphere, the lowest part of the atmosphere, extending from the land or ocean surface typically to ˜8 km at high latitudes, ˜12 km in mid-latitudes, and ˜16 km at low latitudes. That interest arises in large part because of the importance of aerosol particles in geophysical processes, human health impairment through inhalation, environmental effects through deposition, visibility degradation, and influences on atmospheric radiation and climate.Anthropogenic aerosols are thought to exert a substantial influence on Earth's climate, and the need to quantify this influence has sparked much of the current interest in and research on tropospheric aerosols. The principal mechanisms by which aerosols influence the Earth radiation budget are scattering and absorbing solar radiation (the so-called "direct effects") and modifying clouds and precipitation, thereby affecting both radiation and hydrology (the so-called "indirect effects"). Light scattering by aerosols increases the brightness of the planet, producing a cooling influence. Light-absorbing aerosols such as black carbon exert a warming influence. Aerosols increase the reflectivity of clouds, another cooling influence. These radiative influences are quantified as forcings, where a forcing is a perturbation to the energy balance of the atmosphere-Earth system, expressed in units of watts per square meter, W m-2. A warming influence is denoted a positive forcing, and a cooling influence, negative. The radiative direct and indirect forcings by

  19. Aerosol surface area concentration: a governing factor in new particle formation in Beijing

    Directory of Open Access Journals (Sweden)

    R. Cai

    2017-10-01

    Full Text Available The predominating role of aerosol Fuchs surface area, AFuchs, in determining the occurrence of new particle formation (NPF events in Beijing was elucidated in this study. The analysis was based on a field campaign from 12 March to 6 April 2016 in Beijing, during which aerosol size distributions down to  ∼  1 nm and sulfuric acid concentrations were simultaneously monitored. The 26 days were classified into 11 typical NPF days, 2 undefined days, and 13 non-event days. A dimensionless factor, LΓ, characterized by the relative ratio of the coagulation scavenging rate over the condensational growth rate (Kuang et al., 2010, was applied in this work to reveal the governing factors for NPF events in Beijing. The three parameters determining LΓ are sulfuric acid concentration, the growth enhancement factor characterized by contribution of other gaseous precursors to particle growth, Γ, and AFuchs. Different from other atmospheric environments, such as in Boulder and Hyytiälä, the daily-maximum sulfuric acid concentration and Γ in Beijing varied in a narrow range with geometric standard deviations of 1.40 and 1.31, respectively. A positive correlation between the estimated new particle formation rate, J1.5, and sulfuric acid concentration was found with a mean fitted exponent of 2.4. However, the maximum sulfuric acid concentrations on NPF days were not significantly higher (even lower, sometimes than those on non-event days, indicating that the abundance of sulfuric acid in Beijing was high enough to initiate nucleation, but may not necessarily lead to NPF events. Instead, AFuchs in Beijing varied greatly among days with a geometric standard deviation of 2.56, whereas the variabilities of AFuchs in Tecamac, Atlanta, and Boulder were reported to be much smaller. In addition, there was a good correlation between AFuchs and LΓ in Beijing (R2 = 0.88. Therefore, it was AFuchs that fundamentally determined the occurrence of NPF events

  20. Optical Properties of Biomass Burning Aerosols: Comparison of Experimental Measurements and T-Matrix Calculations

    Directory of Open Access Journals (Sweden)

    Samin Poudel

    2017-11-01

    Full Text Available The refractive index (RI is an important parameter in describing the radiative impacts of aerosols. It is important to constrain the RI of aerosol components, since there is still significant uncertainty regarding the RI of biomass burning aerosols. Experimentally measured extinction cross-sections, scattering cross-sections, and single scattering albedos for white pine biomass burning (BB aerosols under two different burning and sampling conditions were modeled using T-matrix theory. The refractive indices were extracted from these calculations. Experimental measurements were conducted using a cavity ring-down spectrometer to measure the extinction, and a nephelometer to measure the scattering of size-selected aerosols. BB aerosols were obtained by burning white pine using (1 an open fire in a burn drum, where the aerosols were collected in distilled water using an impinger, and then re-aerosolized after several days, and (2 a tube furnace to directly introduce the BB aerosols into an indoor smog chamber, where BB aerosols were then sampled directly. In both cases, filter samples were also collected, and electron microscopy images were used to obtain the morphology and size information used in the T-matrix calculations. The effective radius of the particles collected on filter media from the open fire was approximately 245 nm, whereas it was approximately 76 nm for particles from the tube furnace burns. For samples collected in distilled water, the real part of the RI increased with increasing particle size, and the imaginary part decreased. The imaginary part of the RI was also significantly larger than the reported values for fresh BB aerosol samples. For the particles generated in the tube furnace, the real part of the RI decreased with particle size, and the imaginary part was much smaller and nearly constant. The RI is sensitive to particle size and sampling method, but there was no wavelength dependence over the range considered (500

  1. Dust, Pollution, and Biomass Burning Aerosols in Asian Pacific: A Column Satellite-Surface Perspective

    Science.gov (United States)

    Tsay, Si-Chee

    2004-01-01

    Airborne dusts from northern China contribute a significant part of the air quality problem and, to some extent, regional climatic impact in Asia during spring-time. However, with the economical growth in China, increases in the emission of air pollutants generated from industrial and vehicular sources will not only impact the radiation balance, but adverse health effects to humans all year round. In addition, both of these dust and air pollution clouds can transport swiftly across the Pacific reaching North America within a few days, possessing an even larger scale effect. The Asian dust and air pollution aerosols can be detected by its colored appearance on current Earth observing satellites (e.g., MODIS, SeaWiFS, TOMS, etc.) and its evolution monitored by satellites and surface network. Biomass burning has been a regular practice for land clearing and land conversion in many countries, especially those in Africa, South America, and Southeast Asia. However, the unique climatology of Southeast Asia is very different than that of Africa and South America, such that large-scale biomass burning causes smoke to interact extensively with clouds during the peak-burning season of March to April. Significant global sources of greenhouse gases (e.g., CO2, CH4), chemically active gases (e.g., NO, CO, HC, CH3Br), and atmospheric aerosols are produced by biomass burning processes. These gases influence the Earth-atmosphere system, impacting both global climate and tropospheric chemistry. Some aerosols can serve as cloud condensation nuclei, which play an important role in determining cloud lifetime and precipitation, hence, altering the earth's radiation and water budget. Biomass burning also affects the biogeochemical cycling of nitrogen and carbon compounds from the soil to the atmosphere; the hydrological cycle (i.e., run off and evaporation); land surface reflectivity and emissivity; as well as ecosystem biodiversity and stability. Two new initiatives, EAST-AIRE (East

  2. Development of an Aerosol Opacity Retrieval Algorithm for Use with Multi-Angle Land Surface Images

    Science.gov (United States)

    Diner, D.; Paradise, S.; Martonchik, J.

    1994-01-01

    In 1998, the Multi-angle Imaging SpectroRadiometer (MISR) will fly aboard the EOS-AM1 spacecraft. MISR will enable unique methods for retrieving the properties of atmospheric aerosols, by providing global imagery of the Earth at nine viewing angles in four visible and near-IR spectral bands. As part of the MISR algorithm development, theoretical methods of analyzing multi-angle, multi-spectral data are being tested using images acquired by the airborne Advanced Solid-State Array Spectroradiometer (ASAS). In this paper we derive a method to be used over land surfaces for retrieving the change in opacity between spectral bands, which can then be used in conjunction with an aerosol model to derive a bound on absolute opacity.

  3. Fine aerosol bulk composition measured on WP-3D research aircraft in vicinity of the Northeastern United States – results from NEAQS

    Directory of Open Access Journals (Sweden)

    C. Warneke

    2007-06-01

    Full Text Available During the New England Air Quality Study (NEAQS in the summer of 2004, airborne measurements were made of the major inorganic ions and the water-soluble organic carbon (WSOC of the submicron (PM1.0 aerosol. These and ancillary data are used to describe the overall aerosol chemical characteristics encountered during the study. Fine particle mass was estimated from particle volume and a calculated density based on measured particle composition. Fine particle organic matter (OM was estimated from WSOC and a mass balance analysis. The aerosol over the northeastern United States (U.S. and Canada was predominantly sulfate and associated ammonium, and organic components, although in unique plumes additional ionic components were also periodically above detection limits. In power generation regions, and especially in the Ohio River Valley region, the aerosol tended to be predominantly sulfate (~60% μg μg−1 and apparently acidic, based on an excess of measured anions compared to cations. In all other regions where sulfate concentrations were lower and a smaller fraction of overall mass, the cations and anions were balanced suggesting a more neutral aerosol. In contrast, the WSOC and estimated OM were more spatially uniform and the fraction of OM relative to PM mass was largely influenced by sources of sulfate. The study median OM mass fraction was 40%. Throughout the study region, sulfate and organic aerosol mass were highest near the surface and decreased rapidly with increasing altitude. The relative fraction of organic mass to sulfate was similar throughout all altitudes within the boundary layer (altitude less than 2.5 km, but was significantly higher at altitude layers in the free troposphere (above 2.5 km. A number of distinct biomass burning plumes from fires in Alaska and the Yukon were periodically intercepted, mostly at altitudes between 3 and 4 km. These plumes were associated with highest aerosol concentrations of the study and were

  4. Simultaneous aerosol size distribution and turbidity measurements over St. Louis during METROMEX 1975

    International Nuclear Information System (INIS)

    Laulainen, N.S.; Alkezweeny, A.J.; Thorp, J.M.

    1978-01-01

    An experiment designed to measure aerosol size distributions and turbidity simultaneously over a metropolitan area is described. The particle volume size distributions measured in the city plume are found to be bimodal, with the total particle volume in the fine or submicron mode decreasing dramatically above the inversion. Aerosol extinction coefficients derived from sunphotometer optical depth measurements at four wavelengths are compared to those calculated from the measured size distributions using Mie theory with several different particle refractive indices. The accuracy of the experimental method for determining the aerosol extinction coefficient prevented any meaningful choice of the real part of particle refractive index between 1.5--1.6 and an imaginary part between 0 and -0.1i. Improvements to this type of experiment are discussed

  5. Aerosol measurements on a metal waste volume reduction study

    International Nuclear Information System (INIS)

    Sehmel, G.A.; Schwendiman, L.C.; Lloyd, F.A.; Hodgson, W.H.

    1975-09-01

    Particulates generated in an experiment in which stainless steel scrap was melted by the exothermic reaction between silicon and oxygen were sampled. The objective of the sampling was to characterize the particles in the off-gas stream and to determine the total weight of particles airborne. The objective was only partially achieved since the mass of airborne particles was so large that full-flow sampling was possible only for a short period. The particles were analyzed and found to contain Si, Al, Na, and Ba, with Si representing the greatest component. The aerosol was characterized by being typically condensed fume with primary particles of submicron sizes

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

    DEFF Research Database (Denmark)

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

    1997-01-01

    The process of aerosol deposition on indoor surfaces has implications for human exposure to particulate contaminants of both indoor and outdoor origin. In the radiological context, current accident models assume a uniform Dose Reduction Factor (DRF) of 0.5 for indoor residence during the outdoor...

  7. Climatological aspects of aerosol physical characteristics in Tunisia deduced from sun photometric measurements.

    Science.gov (United States)

    Chaâbane, Mabrouk; Azri, Chafai; Medhioub, Khaled

    2012-01-01

    Atmospheric and climatic data measured at Thala site (Tunisia) for a long-time period (1977-2001) are used to analyse the monthly, seasonal, and annual variations of the aerosol optical depth at 1 μm wavelength. We have shown that aerosol and microphysical properties and the dominating aerosol types depend on seasons. A comparison of the seasonal cycle of aerosol optical characteristics at Thala site showed that the contribution of long-range transported particles is expected to be larger in summer as a consequence of the weather stability typical of this season. Also, the winter decrease in atmospheric turbidity may result from increases in relative humidity and decreases in temperature, leading to increased particle size and mass and increased fall and deposition velocities. The spring and autumn weather patterns usually carry fine dust and sand particles for the desert area to Thala region. The annual behaviour of the aerosol optical depth recorded a period of stead increase started in 1986 until 2001. Trends in atmospheric turbidity after 1988 could be explained other ways by the contribution of the eruption of Mount Pinatubo in 1991 and by local or regional changes in climate or in aerosol emissions.

  8. A new oxidation flow reactor for measuring secondary aerosol formation of rapidly changing emission sources

    Science.gov (United States)

    Simonen, Pauli; Saukko, Erkka; Karjalainen, Panu; Timonen, Hilkka; Bloss, Matthew; Aakko-Saksa, Päivi; Rönkkö, Topi; Keskinen, Jorma; Dal Maso, Miikka

    2017-04-01

    Oxidation flow reactors (OFRs) or environmental chambers can be used to estimate secondary aerosol formation potential of different emission sources. Emissions from anthropogenic sources, such as vehicles, often vary on short timescales. For example, to identify the vehicle driving conditions that lead to high potential secondary aerosol emissions, rapid oxidation of exhaust is needed. However, the residence times in environmental chambers and in most oxidation flow reactors are too long to study these transient effects ( ˜ 100 s in flow reactors and several hours in environmental chambers). Here, we present a new oxidation flow reactor, TSAR (TUT Secondary Aerosol Reactor), which has a short residence time ( ˜ 40 s) and near-laminar flow conditions. These improvements are achieved by reducing the reactor radius and volume. This allows studying, for example, the effect of vehicle driving conditions on the secondary aerosol formation potential of the exhaust. We show that the flow pattern in TSAR is nearly laminar and particle losses are negligible. The secondary organic aerosol (SOA) produced in TSAR has a similar mass spectrum to the SOA produced in the state-of-the-art reactor, PAM (potential aerosol mass). Both reactors produce the same amount of mass, but TSAR has a higher time resolution. We also show that TSAR is capable of measuring the secondary aerosol formation potential of a vehicle during a transient driving cycle and that the fast response of TSAR reveals how different driving conditions affect the amount of formed secondary aerosol. Thus, TSAR can be used to study rapidly changing emission sources, especially the vehicular emissions during transient driving.

  9. Role of near ultraviolet wavelength measurements in the detection and retrieval of absorbing aerosols from space

    Science.gov (United States)

    Mukai, Sonoyo; Fujito, Toshiyuki; Nakata, Makiko; Sano, Itaru

    2017-10-01

    Aerosol remote sensing by ultraviolet (UV) wavelength is established by a Total Ozone Mapping Spectrometer (TOMS) mounted on the long-life satellite Nimbus-7 and continues to make observations using Ozone monitoring instrument (OMI) located on the Aura satellite. For example, TOMS demonstrated that UV radiation (0.331 and 0.360 μm) could easily detect absorbing particles such as mineral dust or smoke aerosols. TOMS-AI (absorbing aerosol index) has been used to identify the absorbing aerosols from space. For an upcoming mission, JAXA/GCOM-C will have the polarization sensor SGLI boarded in December 2017. The SGLI has multi (19)-channels including near UV (0.380 μm) and violet (0.412 μm) wavelengths. This work intends to examine the role of near UV data in the detection of absorbing aerosols similar to TOMS-AI played. In practice, the measurements by GLI mounted on the short Japanese mission JAXA/ADEOS-2, whose data archive period was just 8 months from April to October in 2003, are available for simulation of SGLI data because ADEOS-2/GLI installed near UV and violet channels. First of all, the ratio of data at 0.412 μm to that at 0.380 μm is examined as an indicator to detect absorbing aerosols on a global scale during ADEOS-2 era. It is noted that our research group has developed an efficient algorithm for aerosol retrieval in hazy episodes (dense concentrations of atmospheric aerosols). It can be said that at least this work is an attempt to grasp the biomass burning plumes from the satellite.

  10. Columnar characteristics of aerosols by spectroradiometer measurements in the maritime area of the Cadiz Gulf (Spain)

    Science.gov (United States)

    Vergaz, Ricardo; Cachorro, Victoria E.; de Frutos, Ángel M.; Vilaplana, José M.; de La Morena, Benito A.

    2005-11-01

    Atmospheric aerosol characteristics represented by the spectral aerosol optical depth AOD) and the Ångström turbidity parameter were determined in the coastal area of the Gulf of Cádiz, (southwest of Spain). The columnar aerosol properties presented here correspond to the 1996-1999 period, and were obtained by solar direct irradiance measurements carried out by a Licor1800 spectroradiometer. The performance of this type of medium-spectral resolution radiometric system is analysed over the measured period. The detailed spectral information of these irradiance measurements enabled the use of selected non-absorption gases spectral windows to determine the columnar spectral AOD that was modelled by Ångström formula to obtain the coefficient. Temporal evolutions of instantaneous values together with a general statistical analysis represented by seasonal values, frequency distributions and some representative correlations for the AOD and the derived Ångström coefficient gave us the first insight of aerosol characteristics in this coastal area. Special attention was paid to the analysis of these aerosol properties at the nominal wavelengths of 440 nm, 670 nm, 870 nm and 1020 nm for the near-future comparisons with the Cimel sun-photometer data. However, taking the most representative aerosol wavelength of 500 nm, the variability of the AOD ranges from 0.005 to 0.53, with a mean of 0.12 (s.d = 0.07) and that of the parameter is given by a mean value of 0.93 (s.d. = 0.58) falling inside the range of marine aerosols. A quantitative discrimination of aerosol types was conducted on the basis of the spectral aerosol properties and air mass back trajectory analysis, which resulted in a mixed type because of the specificity of this area, given by very frequent desert dust episodes, continental and polluted local influences. This study represents the first extended data characterization about columnar properties of aerosols in Spain which has been continued by Cimel

  11. Assessment of cirrus cloud and aerosol radiative effect in South-East Asia by ground-based NASA MPLNET lidar network data and CALIPSO satellite measurements

    Science.gov (United States)

    Lolli, Simone; Campbell, James R.; Lewis, Jasper R.; Welton, Ellsworth J.; Di Girolamo, Paolo; Fatkhuroyan, Fatkhuroyan; Gu, Yu; Marquis, Jared W.

    2017-10-01

    Aerosol, together with cirrus clouds, play a fundamental role in the earth-atmosphere system radiation budget, especially at tropical latitudes, where the Earth surface coverage by cirrus cloud can easily reach 70%. In this study we evaluate the combined aerosol and cirrus cloud net radiative effects in a wild and barren region like South East Asia. This part of the world is extremely vulnerable to climate change and it is source of important anthropogenic and natural aerosol emissions. The analysis has been carried out by computing cirrus cloud and aerosol net radiative effects through the Fu-Liou-Gu atmospheric radiative transfer model, adequately adapted to input lidar measurements, at surface and top-of-the atmosphere. The aerosol radiative effects were computed respectively using the retrieved lidar extinction from Cloud-Aerosol Lidar with Orthogonal Polarization in 2011 and 2012 and the lidar on-board of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations for the South East Asia Region (27N-12S, 77E-132E) with 5° x 5° spatial resolution. To assess the cirrus cloud radiative effect, we used the ground-based Micro Pulse Lidar Network measurements at Singapore permanent observational site. Results put in evidence that strong aerosol emission areas are related on average to a net surface cooling. On the contrary, cirrus cloud radiative effect shows a net daytime positive warming of the system earth-atmosphere. This effect is weak over the ocean where the albedo is lower and never counter-balances the net cooling produced by aerosols. The net cooling is stronger in 2011, with an associated reduction in precipitations by the four of the five rain-gauges stations deployed in three regions as Sumatra, Kalimantan and Java with respect to 2012. We can speculate that aerosol emissions may be associated with lower rainfall, however some very important phenomena as El Nino Southern Oscillation , Madden-Julian Oscillation, Monsoon and Indian Dipole are not

  12. Aerosol measurements, morphological analysis and evaluation of the dynamic shape factor during the TVMA experiment

    International Nuclear Information System (INIS)

    Tarroni, G.; Castellani, C.M.; De Zaiacomo, T.

    1989-05-01

    In the frame of a CEC program concerning studies on the behaviour of aerosols produced in sodium fire (CONT Group), a test called TVMA was projected for the purpose of comparing code calculations with experimental data. The test took place on May 17, 1988 at the CEA CEN-Cadarache. CEA looked after execution of the sodium pool fire and the main parameter measurements. A British (UKAEA) and an Italian (ENEA) team participated in the test with the aim of carrying out measurements on aerosol parameters. The main results obtained by the ENEA team using its own instrumentation, concerning mass aerosol concentration, granulometry and morphological analyses of particles, are reported. The dynamic shape factor for particles in the aerodynamic range 1.9-7 μm, as evaluated by measuring geometric particle sizes after their aerodynamic separation, is also presented. (author)

  13. Outdoor chamber measurements of biological aerosols with a passive FTIR spectrometer

    Science.gov (United States)

    D'Amico, Francis M.; Emge, Darren K.; Roelant, Geoffrey J.

    2004-02-01

    Outdoor measurements of dry bacillus subtilis (BG) spores were conducted with a passive Fourier transform infrared (FTIR) spectrometer using two types of chambers. One was a large open-ended cell, and the other was a canyon of similar dimensions. The canyon exposes the aerosol plume to downwelling sky radiance, while the open-ended cell does not. The goal of the experiments was to develop a suitable test methodology for evaluation of passive standoff detectors for open-air aerosol measurements. Dry BG aerosol particles were dispersed with a blower through an opening in the side of the chamber to create a pseudo-stationary plume, wind conditions permitting. Numerous trials were performed with the FTIR spectrometer positioned to view mountain, sky and mixed mountain-sky backgrounds. This paper will discuss the results of the FTIR measurements for BG and Kaolin dust releases.

  14. Aerosol-Induced Radiative Flux Changes Off the United States Mid-Atlantic Coast: Comparison of Values Calculated from Sunphotometer and In Situ Data with Those Measured by Airborne Pyranometer

    Science.gov (United States)

    Russell, P. B.; Livingston, J. M.; Hignett, P.; Kinne, S.; Wong, J.; Chien, A.; Bergstrom, R.; Durkee, P.; Hobbs, P. V.

    2000-01-01

    The Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) measured a variety of aerosol radiative effects (including flux changes) while simultaneously measuring the chemical, physical, and optical properties of the responsible aerosol particles. Here we use TARFOX-determined aerosol and surface properties to compute shortwave radiative flux changes for a variety of aerosol situations, with midvisible optical depths ranging from 0.06 to 0.55. We calculate flux changes by several techniques with varying degrees of sophistication, in part to investigate the sensitivity of results to computational approach. We then compare computed flux changes to those determined from aircraft measurements. Calculations using several approaches yield downward and upward flux changes that agree with measurements. The agreement demonstrates closure (i.e. consistency) among the TARFOX-derived aerosol properties, modeling techniques, and radiative flux measurements. Agreement between calculated and measured downward flux changes is best when the aerosols are modeled as moderately absorbing (midvisible single-scattering albedos between about 0.89 and 0.93), in accord with independent measurements of the TARPOX aerosol. The calculated values for instantaneous daytime upwelling flux changes are in the range +14 to +48 W/sq m for midvisible optical depths between 0.2 and 0.55. These values are about 30 to 100 times the global-average direct forcing expected for the global-average sulfate aerosol optical depth of 0.04. The reasons for the larger flux changes in TARFOX include the relatively large optical depths and the focus on cloud-free, daytime conditions over the dark ocean surface. These are the conditions that produce major aerosol radiative forcing events and contribute to any global-average climate effect.

  15. Trace elements in the sea surface microlayer: rapid responses to changes in aerosol deposition

    Directory of Open Access Journals (Sweden)

    Alina M. Ebling

    2017-08-01

    Full Text Available Natural and anthropogenic aerosols are a significant source of trace elements to oligotrophic ocean surface waters, where they provide episodic pulses of limiting micronutrients for the microbial community. However, little is known about the fate of trace elements at the air-sea interface, i.e. the sea surface microlayer. In this study, samples of aerosols, sea surface microlayer, and underlying water column were collected in the Florida Keys during a dusty season (July 2014 and non-dusty season (May 2015 and analyzed for the dissolved and particulate elements Al, Fe, Ni, Cu, Zn, and Pb. Microlayer samples were collected using a cylinder of ultra-pure SiO2 (quartz glass, a novel adaptation of the glass plate technique. A significant dust deposition event occurred during the 2014 sampling period which resulted in elevated concentrations of trace elements in the microlayer. Residence times in the microlayer from this event ranged from 12 to 94 minutes for dissolved trace elements and from 1.3 to 3.4 minutes for particulate trace elements. These residence times are potentially long enough for the atmospherically derived trace elements to undergo chemical and biological alterations within the microlayer. Characterizing the trace element distributions within the three regimes is an important step towards our overall goals of understanding the rates and mechanisms of the solubilization of trace elements following aeolian dust deposition and how this might affect microorganisms in surface waters.

  16. Rapid generation of protein aerosols and nanoparticles via surface acoustic wave atomization

    International Nuclear Information System (INIS)

    Alvarez, Mar; Friend, James; Yeo, Leslie Y

    2008-01-01

    We describe the fabrication of a surface acoustic wave (SAW) atomizer and show its ability to generate monodisperse aerosols and particles for drug delivery applications. In particular, we demonstrate the generation of insulin liquid aerosols for pulmonary delivery and solid protein nanoparticles for transdermal and gastrointestinal delivery routes using 20 MHz SAW devices. Insulin droplets around 3 μm were obtained, matching the optimum range for maximizing absorption in the alveolar region. A new approach is provided to explain these atomized droplet diameters by returning to fundamental physical analysis and considering viscous-capillary and inertial-capillary force balance rather than employing modifications to the Kelvin equation under the assumption of parametric forcing that has been extended to these frequencies in past investigations. In addition, we consider possible mechanisms by which the droplet ejections take place with the aid of high-speed flow visualization. Finally, we show that nanoscale protein particles (50-100 nm in diameter) were obtained through an evaporative process of the initial aerosol, the final size of which could be controlled merely by modifying the initial protein concentration. These results illustrate the feasibility of using SAW as a novel method for rapidly producing particles and droplets with a controlled and narrow size distribution.

  17. Role of volcanic and anthropogenic aerosols in the recent global surface warming slowdown

    Science.gov (United States)

    Smith, Doug M.; Booth, Ben B. B.; Dunstone, Nick J.; Eade, Rosie; Hermanson, Leon; Jones, Gareth S.; Scaife, Adam A.; Sheen, Katy L.; Thompson, Vikki

    2016-10-01

    The rate of global mean surface temperature (GMST) warming has slowed this century despite the increasing concentrations of greenhouse gases. Climate model experiments show that this slowdown was largely driven by a negative phase of the Pacific Decadal Oscillation (PDO), with a smaller external contribution from solar variability, and volcanic and anthropogenic aerosols. The prevailing view is that this negative PDO occurred through internal variability. However, here we show that coupled models from the Fifth Coupled Model Intercomparison Project robustly simulate a negative PDO in response to anthropogenic aerosols implying a potentially important role for external human influences. The recovery from the eruption of Mount Pinatubo in 1991 also contributed to the slowdown in GMST trends. Our results suggest that a slowdown in GMST trends could have been predicted in advance, and that future reduction of anthropogenic aerosol emissions, particularly from China, would promote a positive PDO and increased GMST trends over the coming years. Furthermore, the overestimation of the magnitude of recent warming by models is substantially reduced by using detection and attribution analysis to rescale their response to external factors, especially cooling following volcanic eruptions. Improved understanding of external influences on climate is therefore crucial to constrain near-term climate predictions.

  18. Dynamic Bubble Surface Tension Measurements in Northwest Atlantic Seawater

    Science.gov (United States)

    Kieber, D. J.; Long, M. S.; Keene, W. C.; Kinsey, J. D.; Frossard, A. A.; Beaupre, S. R.; Duplessis, P.; Maben, J. R.; Lu, X.; Chang, R.; Zhu, Y.; Bisgrove, J.

    2017-12-01

    Numerous reports suggest that most organic matter (OM) associated with newly formed primary marine aerosol (PMA) originates from the sea-surface microlayer. However, surface-active OM rapidly adsorbs onto bubble surfaces in the water column and is ejected into the atmosphere when bubbles burst at the air-water interface. Here we present dynamic surface tension measurements of bubbles produced in near surface seawater from biologically productive and oligotrophic sites and in deep seawater collected from 2500 m in the northwest Atlantic. In all cases, the surface tension of bubble surfaces decreased within seconds after the bubbles were exposed to seawater. These observations demonstrate that bubble surfaces are rapidly saturated by surfactant material scavenged from seawater. Spatial and diel variability in bubble surface evolution indicate corresponding variability in surfactant concentrations and/or composition. Our results reveal that surface-active OM is found throughout the water column, and that at least some surfactants are not of recent biological origin. Our results also support the hypothesis that the surface microlayer is a minor to negligible source of OM associated with freshly produced PMA.

  19. Highly controlled, reproducible measurements of aerosol emissions from combustion of a common African biofuel source

    Science.gov (United States)

    Haslett, Sophie L.; Thomas, J. Chris; Morgan, William T.; Hadden, Rory; Liu, Dantong; Allan, James D.; Williams, Paul I.; Keita, Sekou; Liousse, Cathy; Coe, Hugh

    2018-01-01

    Particulate emissions from biomass burning can both alter the atmosphere's radiative balance and cause significant harm to human health. However, due to the large effect on emissions caused by even small alterations to the way in which a fuel burns, it is difficult to study particulate production of biomass combustion mechanistically and in a repeatable manner. In order to address this gap, in this study, small wood samples sourced from Côte D'Ivoire in West Africa were burned in a highly controlled laboratory environment. The shape and mass of samples, available airflow and surrounding thermal environment were carefully regulated. Organic aerosol and refractory black carbon emissions were measured in real time using an Aerosol Mass Spectrometer and a Single Particle Soot Photometer, respectively. This methodology produced remarkably repeatable results, allowing aerosol emissions to be mapped directly onto different phases of combustion. Emissions from pyrolysis were visible as a distinct phase before flaming was established. After flaming combustion was initiated, a black-carbon-dominant flame was observed during which very little organic aerosol was produced, followed by a period that was dominated by organic-carbon-producing smouldering combustion, despite the presence of residual flaming. During pyrolysis and smouldering, the two phases producing organic aerosol, distinct mass spectral signatures that correspond to previously reported variations in biofuel emissions measured in the atmosphere are found. Organic aerosol emission factors averaged over an entire combustion event were found to be representative of the time spent in the pyrolysis and smouldering phases, rather than reflecting a coupling between emissions and the mass loss of the sample. Further exploration of aerosol yields from similarly carefully controlled fires and a careful comparison with data from macroscopic fires and real-world emissions will help to deliver greater constraints on the

  20. In situ measurements of cloud microphysics and aerosol over coastal Antarctica during the MAC campaign

    Science.gov (United States)

    O'Shea, Sebastian J.; Choularton, Thomas W.; Flynn, Michael; Bower, Keith N.; Gallagher, Martin; Crosier, Jonathan; Williams, Paul; Crawford, Ian; Fleming, Zoë L.; Listowski, Constantino; Kirchgaessner, Amélie; Ladkin, Russell S.; Lachlan-Cope, Thomas

    2017-11-01

    During austral summer 2015, the Microphysics of Antarctic Clouds (MAC) field campaign collected unique and detailed airborne and ground-based in situ measurements of cloud and aerosol properties over coastal Antarctica and the Weddell Sea. This paper presents the first results from the experiment and discusses the key processes important in this region, which is critical to predicting future climate change. The sampling was predominantly of stratus clouds, at temperatures between -20 and 0 °C. These clouds were dominated by supercooled liquid water droplets, which had a median concentration of 113 cm-3 and an interquartile range of 86 cm-3. Both cloud liquid water content and effective radius increased closer to cloud top. The cloud droplet effective radius increased from 4 ± 2 µm near cloud base to 8 ± 3 µm near cloud top. Cloud ice particle concentrations were highly variable with the ice tending to occur in small, isolated patches. Below approximately 1000 m, glaciated cloud regions were more common at higher temperatures; however, the clouds were still predominantly liquid throughout. When ice was present at temperatures higher than -10 °C, secondary ice production most likely through the Hallett-Mossop mechanism led to ice concentrations 1 to 3 orders of magnitude higher than the number predicted by commonly used primary ice nucleation parameterisations. The drivers of the ice crystal variability are investigated. No clear dependence on the droplet size distribution was found. The source of first ice in the clouds remains uncertain but may include contributions from biogenic particles, blowing snow or other surface ice production mechanisms. The concentration of large aerosols (diameters 0.5 to 1.6 µm) decreased with altitude and were depleted in air masses that originated over the Antarctic continent compared to those more heavily influenced by the Southern Ocean and sea ice regions. The dominant aerosol in the region was hygroscopic in nature, with

  1. Consistency of aerosols above clouds characterization from A-Train active and passive measurements

    Science.gov (United States)

    Deaconu, Lucia T.; Waquet, Fabien; Josset, Damien; Ferlay, Nicolas; Peers, Fanny; Thieuleux, François; Ducos, Fabrice; Pascal, Nicolas; Tanré, Didier; Pelon, Jacques; Goloub, Philippe

    2017-09-01

    This study presents a comparison between the retrieval of optical properties of aerosol above clouds (AAC) from different techniques developed for the A-Train sensors CALIOP/CALIPSO and POLDER/PARASOL. The main objective is to analyse the consistency between the results derived from the active and the passive measurements. We compare the aerosol optical thickness (AOT) above optically thick clouds (cloud optical thickness (COT) larger than 3) and their Ångström exponent (AE). These parameters are retrieved with the CALIOP operational method, the POLDER operational polarization method and the CALIOP-based depolarization ratio method (DRM) - for which we also propose a calibrated version (denominated DRMSODA, where SODA is the Synergized Optical Depth of Aerosols). We analyse 6 months of data over three distinctive regions characterized by different types of aerosols and clouds. Additionally, for these regions, we select three case studies: a biomass-burning event over the South Atlantic Ocean, a Saharan dust case over the North Atlantic Ocean and a Siberian biomass-burning event over the North Pacific Ocean. Four and a half years of data are studied over the entire globe for distinct situations where aerosol and cloud layers are in contact or vertically separated. Overall, the regional analysis shows a good correlation between the POLDER and the DRMSODA AOTs when the microphysics of aerosols is dominated by fine-mode particles of biomass-burning aerosols from southern Africa (correlation coefficient (R2) of 0.83) or coarse-mode aerosols of Saharan dust (R2 of 0.82). A good correlation between these methods (R2 of 0.68) is also observed in the global treatment, when the aerosol and cloud layers are separated well. The analysis of detached layers also shows a mean difference in AOT of 0.07 at 532 nm between POLDER and DRMSODA at a global scale. The correlation between the retrievals decreases when a complex mixture of aerosols is expected (R2 of 0.37) - as in the

  2. Measurement for Surface Tension of Aqueous Inorganic Salt

    Directory of Open Access Journals (Sweden)

    Jiming Wen

    2018-03-01

    Full Text Available Bubble columns are effective means of filtration in filtered containment venting systems. Here, the surface tension has a significant influence on bubble size distribution and bubble deformation, which have a strong impact on the behavior of the bubble column. The influence of aqueous inorganic compounds on the surface tension depends on the electrolytic activity, Debye length, entropy of ion hydration, and surface deficiencies or excess. In this work, the surface tensions of same specific aqueous solutions have been measured by different methods including platinum plate method, platinum ring method, and maximum bubble pressure method. The measured surface tensions of both sodium hydroxide and sodium thiosulfate are less than that of water. As solution temperature ranges from 20 to 75°C, the surface tension of 0.5 mol/L sodium hydroxide solution decreases from 71 to 55 mN/m while that of 1 mol/L solution decreases from 60 to 45 mN/m. Similarly during the same temperature range, the surface tension of 0.5 mol/L sodium thiosulfate decreases from 70 to 38 mN/m, and that of 1 mol/L sodium thiosulfate is between 68 and 36 mN/m. The analysis for the influence mechanism of aqueous inorganic on surface tension is provided. In addition, experimental results show that the surface tension of solid aerosol suspension liquid has no obvious difference from that of distilled water.

  3. Aerosol characterization study using multi-spectrum remote sensing measurement techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Glen, Crystal Chanea; Sanchez, Andres L.; Lucero, Gabriel Anthony; Schmitt, Randal L.; Johnson, Mark S.; Tezak, Matthew S; Servantes, Brandon Lee

    2013-09-01

    A unique aerosol flow chamber coupled with a bistatic LIDAR system was implemented to measure the optical scattering cross sections and depolarization ratio of common atmospheric particulates. Each of seven particle types (ammonium sulfate, ammonium nitrate, sodium chloride, potassium chloride, black carbon and Arizona road dust) was aged by three anthropogenically relevant mechanisms: 1. Sulfuric acid deposition, 2. Toluene ozonolysis reactions, and 3. m-Xylene ozonolysis reactions. The results of pure particle scattering properties were compared with their aged equivalents. Results show that as most particles age under industrial plume conditions, their scattering cross sections are similar to pure black carbon, which has significant impacts to our understanding of aerosol impacts on climate. In addition, evidence emerges that suggest chloride-containing aerosols are chemically altered during the organic aging process. Here we present the direct measured scattering cross section and depolarization ratios for pure and aged atmospheric particulates.

  4. Techniques for measuring aerosol attenuation using the Central Laser Facility at the Pierre Auger Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Collaboration, The Pierre Auger

    2013-04-01

    The Pierre Auger Observatory in Malargüe, Argentina, is designed to study the properties of ultra-high energy cosmic rays with energies above 10(18)eV. It is a hybrid facility that employs a Fluorescence Detector to perform nearly calorimetric measurements of Extensive Air Shower energies. To obtain reliable calorimetric information from the FD, the atmospheric conditions at the observatory need to be continuously monitored during data acquisition. In particular, light attenuation due to aerosols is an important atmospheric correction. The aerosol concentration is highly variable, so that the aerosol attenuation needs to be evaluated hourly. We use light from the Central Laser Facility, located near the center of the observatory site, having an optical signature comparable to that of the highest energy showers detected by the FD. This paper presents two procedures developed to retrieve the aerosol attenuation of fluorescence light from CLF laser shots. Cross checks between the two methods demonstrate that results from both analyses are compatible, and that the uncertainties are well understood. The measurements of the aerosol attenuation provided by the two procedures are currently used at the Pierre Auger Observatory to reconstruct air shower data.

  5. A new technique for measuring aerosols with moonlight observations and a sky background model

    Science.gov (United States)

    Jones, Amy; Noll, Stefan; Kausch, Wolfgang; Kimeswenger, Stefan; Szyszka, Ceszary; Unterguggenberger, Stefanie

    2014-05-01

    There have been an ample number of studies on aerosols in urban, daylight conditions, but few for remote, nocturnal aerosols. We have developed a new technique for investigating such aerosols using our sky background model and astronomical observations. With a dedicated observing proposal we have successfully tested this technique for nocturnal, remote aerosol studies. This technique relies on three requirements: (a) sky background model, (b) observations taken with scattered moonlight, and (c) spectrophotometric standard star observations for flux calibrations. The sky background model was developed for the European Southern Observatory and is optimized for the Very Large Telescope at Cerro Paranal in the Atacama desert in Chile. This is a remote location with almost no urban aerosols. It is well suited for studying remote background aerosols that are normally difficult to detect. Our sky background model has an uncertainty of around 20 percent and the scattered moonlight portion is even more accurate. The last two requirements are having astronomical observations with moonlight and of standard stars at different airmasses, all during the same night. We had a dedicated observing proposal at Cerro Paranal with the instrument X-Shooter to use as a case study for this method. X-Shooter is a medium resolution, echelle spectrograph which covers the wavelengths from 0.3 to 2.5 micrometers. We observed plain sky at six different distances (7, 13, 20, 45, 90, and 110 degrees) to the Moon for three different Moon phases (between full and half). Also direct observations of spectrophotometric standard stars were taken at two different airmasses for each night to measure the extinction curve via the Langley method. This is an ideal data set for testing this technique. The underlying assumption is that all components, other than the atmospheric conditions (specifically aerosols and airglow), can be calculated with the model for the given observing parameters. The scattered

  6. From BASE-ASIA Toward 7-SEAS: A Satellite-Surface Perspective of Boreal Spring Biomass-Burning Aerosols and Clouds in Southeast Asia

    Science.gov (United States)

    Tsay, Si-Chee; Hsu, N. Christina; Lau, William K.-M.; Li, Can; Gabriel, Philip M.; Ji, Qiang; Holben, Brent N.; Welton, E. Judd; Nguyen, Anh X.; Janjai, Serm; hide

    2013-01-01

    In this paper, we present recent field studies conducted by NASA's SMART-COMMIT (and ACHIEVE, to be operated in 2013) mobile laboratories, jointly with distributed ground-based networks (e.g., AERONET, http://aeronet.gsfc.nasa.gov/ and MPLNET, http://mplnet.gsfc.nasa.gov/) and other contributing instruments over northern Southeast Asia. These three mobile laboratories, collectively called SMARTLabs (cf. http://smartlabs.gsfc.nasa.gov/, Surface-based Mobile Atmospheric Research & Testbed Laboratories) comprise a suite of surface remote sensing and in-situ instruments that are pivotal in providing high spectral and temporal measurements, complementing the collocated spatial observations from various Earth Observing System (EOS) satellites. A satellite-surface perspective and scientific findings, drawn from the BASE-ASIA (2006) field deployment as well as a series of ongoing 7-SEAS (2010-13) field activities over northern Southeast Asia are summarized, concerning (i) regional properties of aerosols from satellite and in situ measurements, (ii) cloud properties from remote sensing and surface observations, (iii) vertical distribution of aerosols and clouds, and (iv) regional aerosol radiative effects and impact assessment. The aerosol burden over Southeast Asia in boreal spring, attributed to biomass burning, exhibits highly consistent spatial and temporal distribution patterns, with major variability arising from changes in the magnitude of the aerosol loading mediated by processes ranging from large-scale climate factors to diurnal meteorological events. Downwind from the source regions, the tightly coupled-aerosolecloud system provides a unique, natural laboratory for further exploring the micro- and macro-scale relationships of the complex interactions. The climatic significance is presented through large-scale anti-correlations between aerosol and precipitation anomalies, showing spatial and seasonal variability, but their precise cause-and-effect relationships

  7. Estimating a relationship between aerosol optical thickness and surface wind speed over the ocean

    OpenAIRE

    Glantz , P.; Nilsson , D. E.; Von Hoyningen-Huene , W.

    2006-01-01

    International audience; Retrieved aerosol optical thickness (AOT) based on data obtained by the Sea viewing Wide Field Sensor (SeaWiFS) is combined with surface wind speed, obtained at the European Centre for Medium-Range Weather Forecasts (ECMWFs), over the North Pacific for September 2001. In this study a cloud screening approach is introduced in an attempt to exclude pixels partly or fully covered by clouds. The relatively broad swath width for which the nadir looking SeaWiFS instrument sc...

  8. iSPEX: everybody can measure atmospheric aerosols with a smartphone spectropolarimeter

    Science.gov (United States)

    Snik, F.; Heikamp, S.; de Boer, J.; Keller, C. U.; van Harten, G.; Smit, J. M.; Rietjens, J. H. H.; Hasekamp, O.; Stam, D. M.; Volten, H.; iSPEX Team

    2012-04-01

    An increasing amount people carry a mobile phone with internet connection, camera and large computing power. iSPEX, a spectropolarimetric add-on with complementary app, instantly turns a smartphone into a scientific instrument to measure dust and other aerosols in our atmosphere. A measurement involves scanning the blue sky, which yields the angular behavior of the degree of linear polarization as a function of wavelength, which can unambiguously be interpreted in terms of size, shape and chemical composition of the aerosols in the sky directly above. The measurements are tagged with location and pointing information, and submitted to a central database where they will be interpreted and compiled into an aerosol map. Through crowdsourcing, many people will thus be able to contribute to a better assessment of health risks of particulate matter and of whether or not volcanic ash clouds are dangerous for air traffic. It can also contribute to the understanding of the relationship between atmospheric aerosols and climate change. We will give a live presentation of the first iSPEX prototype. Furthermore, we will present the design and the plans for producing the iSPEX add-on, app and website. We aim to distribute thousands of iSPEX units, such that a unique network of aerosol measurement equipment is created. Many people will thus contribute to the solution of several urgent social and scientific problems, and learn about the nature of light, remote sensing and the issues regarding atmospheric aerosols in the process. In particular we focus on school classes where smartphones are usually considered a nuisance, whereas now they can be a crucial part of various educational programs in science class.

  9. Aerosol source apportionment from 1-year measurements at the CESAR tower in Cabauw, the Netherlands

    Directory of Open Access Journals (Sweden)

    P. Schlag

    2016-07-01

    Full Text Available Intensive measurements of submicron aerosol particles and their chemical composition were performed with an Aerosol Chemical Speciation Monitor (ACSM at the Cabauw Experimental Site for Atmospheric Research (CESAR in Cabauw, the Netherlands, sampling at 5 m height above ground. The campaign lasted nearly 1 year from July 2012 to June 2013 as part of the EU-FP7-ACTRIS project (Q-ACSM Network. Including equivalent black carbon an average particulate mass concentration of 9.50 µg m−3 was obtained during the whole campaign with dominant contributions from ammonium nitrate (45 %, organic aerosol (OA, 29 %, and ammonium sulfate (19 %. There were 12 exceedances of the World Health Organization (WHO PM2.5 daily mean limit (25 µg m−3 observed at this rural site using PM1 instrumentation only. Ammonium nitrate and OA represented the largest contributors to total particulate matter during periods of exceedance. Source apportionment of OA was performed season-wise by positive matrix factorization (PMF using the multilinear engine 2 (ME-2 controlled via the source finder (SoFi. Primary organic aerosols were attributed mainly to traffic (8–16 % contribution to total OA, averaged season-wise and biomass burning (0–23 %. Secondary organic aerosols (SOAs, 61–84 % dominated the organic fraction during the whole campaign, particularly on days with high mass loadings. A SOA factor which is attributed to humic-like substances (HULIS was identified as a highly oxidized background aerosol in Cabauw. This shows the importance of atmospheric aging processes for aerosol concentration at this rural site. Due to the large secondary fraction, the reduction of particulate mass at this rural site is challenging on a local scale.

  10. Comparing multiple model-derived aerosol optical properties to spatially collocated ground-based and satellite measurements

    Science.gov (United States)

    Ocko, Ilissa B.; Ginoux, Paul A.

    2017-04-01

    Anthropogenic aerosols are a key factor governing Earth's climate and play a central role in human-caused climate change. However, because of aerosols' complex physical, optical, and dynamical properties, aerosols are one of the most uncertain aspects of climate modeling. Fortunately, aerosol measurement networks over the past few decades have led to the establishment of long-term observations for numerous locations worldwide. Further, the availability of datasets from several different measurement techniques (such as ground-based and satellite instruments) can help scientists increasingly improve modeling efforts. This study explores the value of evaluating several model-simulated aerosol properties with data from spatially collocated instruments. We compare aerosol optical depth (AOD; total, scattering, and absorption), single-scattering albedo (SSA), Ångström exponent (α), and extinction vertical profiles in two prominent global climate models (Geophysical Fluid Dynamics Laboratory, GFDL, CM2.1 and CM3) to seasonal observations from collocated instruments (AErosol RObotic NETwork, AERONET, and Cloud-Aerosol Lidar with Orthogonal Polarization, CALIOP) at seven polluted and biomass burning regions worldwide. We find that a multi-parameter evaluation provides key insights on model biases, data from collocated instruments can reveal underlying aerosol-governing physics, column properties wash out important vertical distinctions, and improved models does not mean all aspects are improved. We conclude that it is important to make use of all available data (parameters and instruments) when evaluating aerosol properties derived by models.

  11. The Influence of Stratospheric Sulphate Aerosol Deployment on the Surface Air Temperature and the Risk of an Abrupt Global Warming

    Directory of Open Access Journals (Sweden)

    Roland von Glasow

    2010-12-01

    Full Text Available We used the ‘Radiative-Convective Model of the Earth-atmosphere system’ (OGIM to investigate the cooling effects induced by sulphur injections into the stratosphere. The ensemble of numerical calculations was based on the A1B scenario from the IPCC Special Report on Emissions Scenarios (SRES. Several geoengineered scenarios were analysed, including the abrupt interruption of these injections in different scenarios and at different dates. We focused on the surface air temperature (SAT anomalies induced by stratospheric sulphate aerosol generated in order to compensate future warming. Results show that continuous deployment of sulphur into the stratosphere could induce a lasting decrease in SAT. Retaining a constant aerosol loading equivalent to 6 TgS would delay the expected global warming by 53 years. Keeping the SAT constant in a context of increasing greenhouse gases (GHGs means that the aerosol loading needs to be increased by 1.9% annually. This would offset the effect of increasing GHG under the A1B scenario. A major focus of this study was on the heating rates of SAT that would arise in different scenarios in case of an abrupt cessation of sulphur injections into the stratosphere. Our model results show that heating rates after geoengineering interruption would be 15–28 times higher than in a case without geoengineering, with likely important consequences for life on Earth. Larger initial sulphate loadings induced more intense warming rates when the geoengineering was stopped at the same time. This implies that, if sulphate loading was increased to maintain constant SAT in the light of increasing GHG concentrations, the later the geoengineering interruption was to occur, the higher the heating rates would be. Consequently, geoengineering techniques like this should only be regarded as last-resort measures and require intense further research should they ever become necessary.

  12. Neutron activation analysis measurements of sub micron aerosol deposition onto a cylinder energized with an alternating electric field

    Energy Technology Data Exchange (ETDEWEB)

    Fila, M S [Toronto Univ., ON (Canada). Dept. of Chemical Engineering and Applied Chemistry

    1994-12-31

    Experimental measurements of aerosol deposition onto a cylinder energized with a 60 Hz electric field were conducted using a neutron activation analysis technique with a hafnium salt aerosol. The measured collection efficiencies were compared to theoretical expressions based on an electrostatic collection mechanism and fair agreement was found. (author). 5 refs., 1 tab., 2 figs.

  13. Measurements and estimation of the columnar optical depth of tropospheric aerosols in the UV spectral region

    Directory of Open Access Journals (Sweden)

    V. E. Cachorro

    2002-04-01

    Full Text Available We report values of the columnar tropospheric aerosol optical depth at UV wavelengths based on experimental measurements of the direct spectral irradiances carried out by a commercial spectroradiometer (Li1800 of Licor company covering the range from 300–1100 nm at two stations with different climate characteristics in Spain. The first station is located in a rural site in north central Spain with continental climate. The data extend from March to the end of October of 1995. The other station is a coastal site in the Gulf of Cádiz (southwest Spain of maritime climate type. This study is mainly focused on the capability of estimating aerosol optical depth values in the UV region based on the extracted information in the visible and near infrared ranges. A first method has been used based on the Ångström turbidity parameters. However, since this method requires detailed spectral information, a second method has also been used, based on the correlation between wavelengths. A correlation has been established between the experimental aerosol optical depth values at 350 nm and 500 nm wavelengths. Although the type of aerosol seems to be the key factor that determines the quality of these estimations, the evaluation of the associated error is necessary to know the behaviour of these estimations in each area of study.Key words. Atmospheric composition and structure (aerosols and particles; transmission and scattering of radiation; troposphere – composition and chemistry

  14. Measurements and estimation of the columnar optical depth of tropospheric aerosols in the UV spectral region

    Directory of Open Access Journals (Sweden)

    V. E. Cachorro

    Full Text Available We report values of the columnar tropospheric aerosol optical depth at UV wavelengths based on experimental measurements of the direct spectral irradiances carried out by a commercial spectroradiometer (Li1800 of Licor company covering the range from 300–1100 nm at two stations with different climate characteristics in Spain. The first station is located in a rural site in north central Spain with continental climate. The data extend from March to the end of October of 1995. The other station is a coastal site in the Gulf of Cádiz (southwest Spain of maritime climate type. This study is mainly focused on the capability of estimating aerosol optical depth values in the UV region based on the extracted information in the visible and near infrared ranges. A first method has been used based on the Ångström turbidity parameters. However, since this method requires detailed spectral information, a second method has also been used, based on the correlation between wavelengths. A correlation has been established between the experimental aerosol optical depth values at 350 nm and 500 nm wavelengths. Although the type of aerosol seems to be the key factor that determines the quality of these estimations, the evaluation of the associated error is necessary to know the behaviour of these estimations in each area of study.

    Key words. Atmospheric composition and structure (aerosols and particles; transmission and scattering of radiation; troposphere – composition and chemistry

  15. Maritime Aerosol Network optical depth measurements and comparison with satellite retrievals from various different sensors

    Science.gov (United States)

    Smirnov, Alexander; Petrenko, Maksym; Ichoku, Charles; Holben, Brent N.

    2017-10-01

    The paper reports on the current status of the Maritime Aerosol Network (MAN) which is a component of the Aerosol Robotic Network (AERONET). A public domain web-based data archive dedicated to MAN activity can be found at https://aeronet.gsfc.nasa.gov/new_web/maritime_aerosol_network.html . Since 2006 over 450 cruises were completed and the data archive consists of more than 6000 measurement days. In this work, we present MAN observations collocated with MODIS Terra, MODIS Aqua, MISR, POLDER, SeaWIFS, OMI, and CALIOP spaceborne aerosol products using a modified version of the Multi-Sensor Aerosol Products Sampling System (MAPSS) framework. Because of different spatio-temporal characteristics of the analyzed products, the number of MAN data points collocated with spaceborne retrievals varied between 1500 matchups for MODIS to 39 for CALIOP (as of August 2016). Despite these unavoidable sampling biases, latitudinal dependencies of AOD differences for all satellite sensors, except for SeaWIFS and POLDER, showed positive biases against ground truth (i.e. MAN) in the southern latitudes (<50° S), and substantial scatter in the Northern Atlantic "dust belt" (5°-15° N). Our analysis did not intend to determine whether satellite retrievals are within claimed uncertainty boundaries, but rather show where bias exists and corrections are needed.

  16. Spectral Aerosol Extinction (SpEx): A New Instrument for In situ Ambient Aerosol Extinction Measurements Across the UV/Visible Wavelength Range

    Science.gov (United States)

    Jordan, C. E.; Anderson, B. E.; Beyersdorf, A. J.; Corr, C. A.; Dibb, J. E.; Greenslade, M. E.; Martin, R. F.; Moore, R. H.; Scheuer, E.; Shook, M. A.; hide

    2015-01-01

    We introduce a new instrument for the measurement of in situ ambient aerosol extinction over the 300-700 nm wavelength range, the Spectral Aerosol Extinction (SpEx) instrument. This measurement capability is envisioned to complement existing in situ instrumentation, allowing for simultaneous measurement of the evolution of aerosol optical, chemical, and physical characteristics in the ambient environment. In this work, a detailed description of the instrument is provided along with characterization tests performed in the laboratory. Measured spectra of NO2 and polystyrene latex spheres agreed well with theoretical calculations. Good agreement was also found with simultaneous aerosol extinction measurements at 450, 530, and 630 nm using CAPS PMex instruments in a series of 22 tests including non-absorbing compounds, dusts, soot, and black and brown carbon analogs. SpEx can more accurately distinguish the presence of brown carbon from other absorbing aerosol due to its 300 nm lower wavelength limit compared to measurements limited to visible wavelengths. In addition, the spectra obtained by SpEx carry more information than can be conveyed by a simple power law fit that is typically defined by the use of Angstrom Exponents. Future improvements aim at lowering detection limits and ruggedizing the instrument for mobile operation.

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

    Science.gov (United States)

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

    2004-01-01

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

  18. Retrieval of Surface Lambert Albedos and Aerosols Optical Depths Using OMEGA Near-IR EPF Observations of Mars

    Science.gov (United States)

    Vincendon, M.; Langevin, Y.; Poulet, F.; Bibring, J.-P.; Gondet, B.

    2007-03-01

    We have analyzed five EPF sequences acquired by OMEGA/Mars Express in the near-IR over ice-free and ice-covered surfaces to retrieve simultaneously the Lambert albedo of the surface and the optical depth of aerosols.

  19. Submicron-sized aerosol and radon progeny measurements in an uranium mine

    International Nuclear Information System (INIS)

    Boulaud, D.; Chouard, J.C.

    1992-01-01

    Submicron-sized aerosol was studied in an uranium mine using an Electrical Aerosol Analyzer and a Differential Mobility Particle Sizer. In addition radon progeny particle size distributions were measured using a prototype instrument developed by us (SDI 2000). With cascade impactor the number weighted mean electrical mobility diameters and the geometric standard deviations ranged respectively from 0.05 to 0.1 μm and 1.8 to 2. The gross alpha activity weighted mean thermodynamic diameters ranged typically from 0.1 to 0.2 μm. 6 refs., 3 figs

  20. Aerosol and monsoon climate interactions over Asia: AEROSOL AND MONSOON CLIMATE INTERACTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhanqing [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Lau, W. K. -M. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Ramanathan, V. [Department of Atmospheric and Climate Sciences, University of California, San Diego California USA; Wu, G. [Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing China; Ding, Y. [National Climate Center, China Meteorological Administration, Beijing China; Manoj, M. G. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Liu, J. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Qian, Y. [Pacific Northwest National Laboratory, Richland Washington USA; Li, J. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Zhou, T. [Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing China; Fan, J. [Pacific Northwest National Laboratory, Richland Washington USA; Rosenfeld, D. [Institute of Earth Sciences, Hebrew University, Jerusalem Israel; Ming, Y. [Geophysical Fluid Dynamic Laboratory, NOAA, Princeton New Jersey USA; Wang, Y. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena California USA; Huang, J. [College of Atmospheric Sciences, Lanzhou University, Lanzhou China; Wang, B. [Department of Atmospheric Sciences, University of Hawaii, Honolulu Hawaii USA; School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing China; Xu, X. [Chinese Academy of Meteorological Sciences, Beijing China; Lee, S. -S. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Cribb, M. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Zhang, F. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Yang, X. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Zhao, C. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Takemura, T. [Research Institute for Applied Mechanics, Kyushu University, Fukuoka Japan; Wang, K. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Xia, X. [Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing China; Yin, Y. [School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing China; Zhang, H. [National Climate Center, China Meteorological Administration, Beijing China; Guo, J. [Chinese Academy of Meteorological Sciences, Beijing China; Zhai, P. M. [Chinese Academy of Meteorological Sciences, Beijing China; Sugimoto, N. [National Institute for Environmental Studies, Tsukuba Japan; Babu, S. S. [Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram India; Brasseur, G. P. [Max Planck Institute for Meteorology, Hamburg Germany

    2016-11-15

    Asian monsoons and aerosols have been studied extensively which are intertwined in influencing the climate of Asia. This paper provides a comprehensive review of ample studies on Asian aerosol, monsoon and their interactions. The region is the primary source of aerosol emissions of varies species, influenced by distinct weather and climatic regimes. On continental scale, aerosols reduce surface insolation and weaken the land-ocean thermal contrast, thus inhibiting the development of monsoons. Locally, aerosol radiative effects alter the thermodynamic stability and convective potential of the lower atmosphere leading to reduced temperatures, increased atmospheric stability, and weakened wind and atmospheric circulation. The atmospheric thermodynamic state may also be altered by the aerosol serving as cloud condensation nuclei or ice nuclei. Many mechanisms have been put forth regarding how aerosols modulate the amplitude, frequency, intensity, and phase of numerous monsoon climate variables. A wide range of theoretical, observational, and modeling findings on the Asian monsoon, aerosols, and their interactions are synthesized. A new paradigm is proposed on investigating aerosol-monsoon interactions, in which natural aerosols such as desert dust, black carbon from biomass burning, and biogenic aerosols from vegetation are considered integral components of an intrinsic aerosol-monsoon climate system, subject to external forcings of global warming, anthropogenic aerosols, and land use and change. Future research on aerosol-monsoon interactions calls for an integrated approach and international collaborations based on long-term sustained observations, process measurements, and improved models, as well as using observations to constrain model simulations and projections.

  1. Advances In Global Aerosol Modeling Applications Through Assimilation of Satellite-Based Lidar Measurements

    Science.gov (United States)

    Campbell, James; Hyer, Edward; Zhang, Jianglong; Reid, Jeffrey; Westphal, Douglas; Xian, Peng; Vaughan, Mark

    2010-05-01

    Modeling the instantaneous three-dimensional aerosol field and its downwind transport represents an endeavor with many practical benefits foreseeable to air quality, aviation, military and science agencies. The recent proliferation of multi-spectral active and passive satellite-based instruments measuring aerosol physical properties has served as an opportunity to develop and refine the techniques necessary to make such numerical modeling applications possible. Spurred by high-resolution global mapping of aerosol source regions, and combined with novel multivariate data assimilation techniques designed to consider these new data streams, operational forecasts of visibility and aerosol optical depths are now available in near real-time1. Active satellite-based aerosol profiling, accomplished using lidar instruments, represents a critical element for accurate analysis and transport modeling. Aerosol source functions, alone, can be limited in representing the macrophysical structure of injection scenarios within a model. Two-dimensional variational (2D-VAR; x, y) assimilation of aerosol optical depth from passive satellite observations significantly improves the analysis of the initial state. However, this procedure can not fully compensate for any potential vertical redistribution of mass required at the innovation step. The expense of an inaccurate vertical analysis of aerosol structure is corresponding errors downwind, since trajectory paths within successive forecast runs will likely diverge with height. In this paper, the application of a newly-designed system for 3D-VAR (x,y,z) assimilation of vertical aerosol extinction profiles derived from elastic-scattering lidar measurements is described [Campbell et al., 2009]. Performance is evaluated for use with the U. S. Navy Aerosol Analysis and Prediction System (NAAPS) by assimilating NASA/CNES satellite-borne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) 0.532 μm measurements [Winker et al., 2009

  2. A method of alpha-radiating nuclide activity measuring in aerosol filters

    International Nuclear Information System (INIS)

    Ignatov, V.P.; Galkina, V.N.

    1992-01-01

    Scintillation method of determination of alpha-radiating nuclide activity in aerosol filters was suggested. The method involves dissolution of the filter in organic solvent, introduction of luminophore into solution prepared, drying of the preparation and measurement of radionuclide activity. Dependences of alpha-radiation detection efficiency on the content of luminophore, filter material, colourless and coloured substances in preparations analyzed were considered

  3. Aerosol emissions from prescribed fires in the United States: A synthesis of laboratory and aircraft measurements

    Science.gov (United States)

    A. A. May; G. R. McMeeking; T. Lee; J. W. Taylor; J. S. Craven; I. Burling; A. P. Sullivan; S. Akagi; J. L. Collett; M. Flynn; H. Coe; S. P. Urbanski; J. H. Seinfeld; R. J. Yokelson; S. M. Kreidenweis

    2014-01-01

    Aerosol emissions from prescribed fires can affect air quality on regional scales. Accurate representation of these emissions in models requires information regarding the amount and composition of the emitted species. We measured a suite of submicron particulate matter species in young plumes emitted from prescribed fires (chaparral and montane ecosystems in California...

  4. Modeling of aerosol formation during biomass combustion in grate furnaces and comparison with measurements

    NARCIS (Netherlands)

    Joeller, M.; Brunner, T.; Obernberger, I.

    2005-01-01

    Results from mathematical modeling of aerosol formation during combustion of woody biomass fuels were compared with results from particle size distribution (PSD) measurements at a pilot-scale biomass combustion unit with moving grate and flame tube boiler. The mathematical model is a plug flow model

  5. Modeling and measurements of urban aerosol processes on the neighborhood scale in Rotterdam, Oslo and Helsinki

    NARCIS (Netherlands)

    Karl, M.; Kukkonen, J.; Keuken, M.P.; Lützenkirchen, S.; Pirjola, L.; Hussein, T.

    2016-01-01

    This study evaluates the influence of aerosol processes on the particle number (PN) concentrations in three major European cities on the temporal scale of 1 h, i.e., on the neighborhood and city scales. We have used selected measured data of particle size distributions from previous campaigns in the

  6. Enhancements of a mechanical lung simulator for ex vivo measuring of aerosol deposition in lungs

    Czech Academy of Sciences Publication Activity Database

    Steiner, T.; Forjan, M.; Kopp, T.; Bureš, Zbyněk; Drauschke, A.

    2012-01-01

    Roč. 57, Suppl.1 (2012), s. 799-802 ISSN 0013-5585 Institutional research plan: CEZ:AV0Z50390512 Keywords : aerosol measurement * lung simulator Subject RIV: FS - Medical Facilities ; Equipment Impact factor: 1.157, year: 2012

  7. Asian industrial lead inputs to the North Pacific evidenced by lead concentrations and isotopic compositions in surface waters and aerosols.

    Science.gov (United States)

    Gallon, Céline; Ranville, Mara A; Conaway, Christopher H; Landing, William M; Buck, Clifton S; Morton, Peter L; Flegal, A Russell

    2011-12-01

    Recent trends of atmospheric lead deposition to the North Pacific were investigated with analyses of lead in aerosols and surface waters collected on the fourth Intergovernmental Oceanographic Commission Contaminant Baseline Survey from May to June, 2002. Lead concentrations of the aerosols varied by 2 orders of magnitude (0.1-26.4 pmol/m(3)) due in part to variations in dust deposition during the cruise. The ranges in lead aerosol enrichment factors relative to iron (1-119) and aluminum (3-168) were similar, evidencing the transport of Asian industrial lead aerosols across the North Pacific. The oceanic deposition of some of those aerosols was substantiated by the gradient of lead concentrations of North Pacific waters, which varied 3-fold (32.7-103.5 pmol/kg), were highest along with the Asian margin of the basin, and decreased eastward. The hypothesized predominance of Asian industrial lead inputs to the North Pacific was further corroborated by the lead isotopic composition of ocean surface waters ((206)Pb/(207)Pb = 1.157-1.169; (208)Pb/(206)Pb = 2.093-2.118), which fell within the range of isotopic ratios reported in Asian aerosols that are primarily attributed to Chinese industrial lead emissions.

  8. Quantitative measurement of aerosol deposition on skin, hair and clothing for dosimetric assessment

    International Nuclear Information System (INIS)

    Roed, J.; Andersson, J.G.; Bell, K.F.; Byrne, M.A.; Fogh, C.L.; Goddard, A.J.H.; Vollmair, D.V.

    1998-01-01

    The deposition to human body surfaces of potentially hazardous aerosol has been investigated through tracer experiments. Particles of different sizes labelled with neutron activatable rare earth tracers were released in test rooms and deposited on volunteers. Various sampling techniques to examine the clearance and retention of the aerosol to skin, hair and clothing were investigated, and a protocol for the most efficient procedure was established and validated. Experiments indicate that the deposition velocity to skin increases linearly with the particle size. A wind tunnel experiment simulating outdoor conditions showed outdoor deposition velocities to be almost an order of magnitude higher than those recorded indoors. Both in vivo and in vitro experiments were conducted, and the influence of various factors, such as surface type, air flow, heating and electrostatics were examined. The dynamics of particle removal from human skin were studied by fluorescence scanning. Using the experimentally determined parameters, a model was established for calculation of radiation doses received from deposition of airborne radioactive aerosol on human body surfaces. It was found that the gamma doses that could be expected from deposition on skin were of the same order of magnitude as the gamma doses received over several years from contamination on outdoor surfaces. Assuming very high dry contamination levels, as were recorded in some areas of Russia after the Chernobyl accident, it was found that beta doses from skin deposition may amount to several Sievert and thus be responsible for a significant cancer risk. (au)

  9. Quantitative measurement of aerosol deposition on skin, hair and clothing for dosimetric assessment

    Energy Technology Data Exchange (ETDEWEB)

    Roed, J.; Andersson, J.G.; Bell, K.F.; Byrne, M.A.; Fogh, C.L.; Goddard, A.J.H.; Vollmair, D.V.

    1998-01-01

    The deposition to human body surfaces of potentially hazardous aerosol has been investigated through tracer experiments. Particles of different sizes labelled with neutron activatable rare earth tracers were released in test rooms and deposited on volunteers. Various sampling techniques to examine the clearance and retention of the aerosol to skin, hair and clothing were investigated, and a protocol for the most efficient procedure was established and validated. Experiments indicate that the deposition velocity to skin increases linearly with the particle size. A wind tunnel experiment simulating outdoor conditions showed outdoor deposition velocities to be almost an order of magnitude higher than those recorded indoors. Both in vivo and in vitro experiments were conducted, and the influence of various factors, such as surface type, air flow, heating and electrostatics were examined. The dynamics of particle removal from human skin were studied by fluorescence scanning. Using the experimentally determined parameters, a model was established for calculation of radiation doses received from deposition of airborne radioactive aerosol on human body surfaces. It was found that the gamma doses that could be expected from deposition on skin were of the same order of magnitude as the gamma doses received over several years from contamination on outdoor surfaces. Assuming very high dry contamination levels, as were recorded in some areas of Russia after the Chernobyl accident, it was found that beta doses from skin deposition may amount to several Sievert and thus be responsible for a significant cancer risk. (au). 12 tabs., 9 ills., 43 refs.

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

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  11. Modeling and measurements of urban aerosol processes on the neighborhood scale in Rotterdam, Oslo and Helsinki

    Science.gov (United States)

    Karl, Matthias; Kukkonen, Jaakko; Keuken, Menno P.; Lützenkirchen, Susanne; Pirjola, Liisa; Hussein, Tareq

    2016-04-01

    This study evaluates the influence of aerosol processes on the particle number (PN) concentrations in three major European cities on the temporal scale of 1 h, i.e., on the neighborhood and city scales. We have used selected measured data of particle size distributions from previous campaigns in the cities of Helsinki, Oslo and Rotterdam. The aerosol transformation processes were evaluated using the aerosol dynamics model MAFOR, combined with a simplified treatment of roadside and urban atmospheric dispersion. We have compared the model predictions of particle number size distributions with the measured data, and conducted sensitivity analyses regarding the influence of various model input variables. We also present a simplified parameterization for aerosol processes, which is based on the more complex aerosol process computations; this simple model can easily be implemented to both Gaussian and Eulerian urban dispersion models. Aerosol processes considered in this study were (i) the coagulation of particles, (ii) the condensation and evaporation of two organic vapors, and (iii) dry deposition. The chemical transformation of gas-phase compounds was not taken into account. By choosing concentrations and particle size distributions at roadside as starting point of the computations, nucleation of gas-phase vapors from the exhaust has been regarded as post tail-pipe emission, avoiding the need to include nucleation in the process analysis. Dry deposition and coagulation of particles were identified to be the most important aerosol dynamic processes that control the evolution and removal of particles. The error of the contribution from dry deposition to PN losses due to the uncertainty of measured deposition velocities ranges from -76 to +64 %. The removal of nanoparticles by coagulation enhanced considerably when considering the fractal nature of soot aggregates and the combined effect of van der Waals and viscous interactions. The effect of condensation and

  12. Modeling and measurements of urban aerosol processes on the neighborhood scale in Rotterdam, Oslo and Helsinki

    Directory of Open Access Journals (Sweden)

    M. Karl

    2016-04-01

    Full Text Available This study evaluates the influence of aerosol processes on the particle number (PN concentrations in three major European cities on the temporal scale of 1 h, i.e., on the neighborhood and city scales. We have used selected measured data of particle size distributions from previous campaigns in the cities of Helsinki, Oslo and Rotterdam. The aerosol transformation processes were evaluated using the aerosol dynamics model MAFOR, combined with a simplified treatment of roadside and urban atmospheric dispersion. We have compared the model predictions of particle number size distributions with the measured data, and conducted sensitivity analyses regarding the influence of various model input variables. We also present a simplified parameterization for aerosol processes, which is based on the more complex aerosol process computations; this simple model can easily be implemented to both Gaussian and Eulerian urban dispersion models. Aerosol processes considered in this study were (i the coagulation of particles, (ii the condensation and evaporation of two organic vapors, and (iii dry deposition. The chemical transformation of gas-phase compounds was not taken into account. By choosing concentrations and particle size distributions at roadside as starting point of the computations, nucleation of gas-phase vapors from the exhaust has been regarded as post tail-pipe emission, avoiding the need to include nucleation in the process analysis. Dry deposition and coagulation of particles were identified to be the most important aerosol dynamic processes that control the evolution and removal of particles. The error of the contribution from dry deposition to PN losses due to the uncertainty of measured deposition velocities ranges from −76 to +64 %. The removal of nanoparticles by coagulation enhanced considerably when considering the fractal nature of soot aggregates and the combined effect of van der Waals and viscous interactions. The effect of

  13. Studies on aerosol properties during ICARB–2006 campaign period ...

    Indian Academy of Sciences (India)

    Continuous and campaign-based aerosol field measurements are essential in understanding funda- ... aerosol mass concentration and aerosol particle size distribution were carried out during the cam- .... the details provided by the supplier, the calibration ..... solar flux at the surface, derived from principal-plane sky.

  14. Measurement of the atmospheric aerosol particle size distribution in a highly polluted mega-city in Southeast Asia (Dhaka-Bangladesh)

    Science.gov (United States)

    Salam, Abdus; Mamoon, Hassan Al; Ullah, Md. Basir; Ullah, Shah M.

    2012-11-01

    Aerosol particle size distribution was measured with an aerodynamic particle sizer (APS) spectrometer continuously from January 21 to April 24, 2006 in Dhaka, Bangladesh. Particles number, surface and mass distributions data were stored automatically with Aerosol Instrument Manager (AIM) software on average every half an hour in a computer attached to the APS. The grand total average of number, surface and mass concentrations were 8.2 × 103 ± 7.8 × 103 particles cm-3, 13.3 × 103 ± 11.8 × 103 μm2 cm-3 and 3.04 ± 2.10 mg m-3, respectively. Fine particles with diameter smaller than 1.0 μm aerodynamic diameter (AD) dominated the number concentration, accounted for 91.7% of the total particles indicating vehicular emissions were dominating in Dhaka air either from fossil fuel burning or compressed natural gas (CNGs). The surface and mass concentrations between 0.5 and 1.0 μm AD were about 56.0% and 26.4% of the total particles, respectively. Remarkable seasonal differences were observed between winter and pre-monsoon seasons with the highest monthly average in January and the lowest in April. Aerosol particles in winter were 3.79 times higher for number, 3.15 times for surface and 2.18 times for mass distributions than during the pre-monsoon season. Weekends had lower concentrations than weekdays due to less vehicular traffic in the streets. Aerosol particles concentrations were about 15.0% (ranging from 9.4% to 17.3%) higher during traffic peak hours (6:00am-8:00pm) than off hours (8:00pm-6:00am). These are the first aerosol size distribution measurements with respect to number, surface and mass concentrations in real time at Dhaka, Bangladesh.

  15. Influence of surface roughness on the elastic-light scattering patterns of micron-sized aerosol particles

    Science.gov (United States)

    Auger, J.-C.; Fernandes, G. E.; Aptowicz, K. B.; Pan, Y.-L.; Chang, R. K.

    2010-04-01

    The relation between the surface roughness of aerosol particles and the appearance of island-like features in their angle-resolved elastic-light scattering patterns is investigated both experimentally and with numerical simulation. Elastic scattering patterns of polystyrene spheres, Bacillus subtilis spores and cells, and NaCl crystals are measured and statistical properties of the island-like intensity features in their patterns are presented. The island-like features for each class of particle are found to be similar; however, principal-component analysis applied to extracted features is able to differentiate between some of the particle classes. Numerically calculated scattering patterns of Chebyshev particles and aggregates of spheres are analyzed and show qualitative agreement with experimental results.

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

    Energy Technology Data Exchange (ETDEWEB)

    Richard A. Ferrare; David D. Turner

    2011-09-01

    Project goals: (1) Use the routine surface and airborne measurements at the ARM SGP site, and the routine surface measurements at the NSA site, to continue our evaluations of model aerosol simulations; (2) Determine the degree to which the Raman lidar measurements of water vapor and aerosol scattering and extinction can be used to remotely characterize the aerosol humidification factor; (3) Use the high temporal resolution CARL data to examine how aerosol properties vary near clouds; and (4) Use the high temporal resolution CARL and Atmospheric Emitted Radiance Interferometer (AERI) data to quantify entrainment in optically thin continental cumulus clouds.

  17. Vertical profiles of urban aerosol complex refractive index in the frame of ESQUIF airborne measurements

    Science.gov (United States)

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

    2008-02-01

    A synergy between lidar, sunphotometer and in situ measurements has been applied to airborne observations performed during the Etude et Simulation de la QUalité de l'air en Ile-de-France (ESQUIF), enabling the retrieval of vertical profiles for the aerosol complex refractive index (ACRI) and single-scattering albedo with a vertical resolution of 200 m over Paris area. The averaged value over the entire planetary boundary layer (PBL) for the ACRI is close to 1.51(±0.02)-i0.017(±0.003) at 532 nm. The single-scattering albedo of the corresponding aerosols is found to be ~0.9 at the same wavelength. A good agreement is found with previous studies for urban aerosols. A comparison of vertical profiles of ACRI with simulations combining in situ measurements and relative humidity (RH) profiles has highlighted a modification in aerosol optical properties linked to their history and the origin of the air mass. The determination of ACRI in the atmospheric column enabled to retrieve vertical profiles of extinction coefficient in accordance with lidar profiles measurements.

  18. The Dedicated Aerosol Retrieval Experiment (DARE): scientific requirements for a dedicated satellite instrument to measure atmospheric aerosols

    NARCIS (Netherlands)

    Decae, R.; Courrèges-Lacoste, G.B.; Leeuw, G. de

    2004-01-01

    DARE (Dedicated Aerosol Retrieval Experiment) is a study to design an instrument for accurate remote sensing of aerosol properties from space. DARE combines useful properties of several existing instruments like TOMS, GOME, ATSR and POLDER. It has a large wavelength range, 330 to 1000 nm, to

  19. Ozone, spectral irradiance and aerosol measurements with the Brewer spectro radiometer

    International Nuclear Information System (INIS)

    Marenco, F.; Di Sarra, A.

    2001-01-01

    In this technical report a detailed description of the Brewer spectro radiometer, a widespread instrument for ozone and ultraviolet radiation, is given. The methodologies used to measure these quantities and for instrument calibration are described in detail. Finally a new methodology, developed by ENEA to derive the aerosol optical depth from the Brewer routine total ozone measurements, is described. This methodology is based on Langley extrapolation, on the determination of the transmissivity of the Brewer neutral density filters, and on a statistically significant number of half days of measurements obtained in could-free conditions. Results of this method, obtained with the Brewer of the ENEA station for climate observations Roberto Sarao, located in the island of Lampedusa, are reported. These results confirm the validity of the method, thanks to independent measurements taken in 1999 with a Multi filter Rotating Shadow band Radiometer. This methodology allows researchers to obtain an aerosol climatology from ozone measurements obtained at several sites world-wide [it

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

    Science.gov (United States)

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

    2008-12-01

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

  1. First measurements and model calculations on the adsorption of radioactive nuclides to Aitken nucleus aerosols

    International Nuclear Information System (INIS)

    Fritz, G.

    From the viewpoint of disaster relief the knowledge of the adsorption coefficient as a function of aerosol size is important. Its theoretical assessment is only possible by completing diffusion theory with Fuchs' theory of limited spheres. To carry out the adsorption experiments SO 4 particles were produced which, because of their high concentration, coagulated further to particles of the size 10 -6 to 10 -5 . Proportionality to the surface of the particles is found. (DG) [de

  2. Quantitative measurement of aerosol deposition on skin, hair and clothing for dosimetric assessment. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Fogh, C.L.; Byrne, M.A.; Andersson, K.G.; Bell, K.F.; Roed, J.; Goddard, A.J.H.; Vollmair, D.V.; Hotchkiss, S.A.M

    1999-06-01

    In the past, very little thought has been given to the processes and implications of deposition of potentially hazardous aerosol directly onto humans. This state of unpreparedness is unsatisfactory and suitable protocols have been developed and validated for tracer experiments to investigate the deposition and subsequent fate of contaminant aerosol on skin, hair and clothing. The main technique applied involves the release and subsequent deposition on volunteers in test rooms of particles of different sizes labelled with neutron activatable rare earth tracers. Experiments indicate that the deposition velocity to skin increases linearly with the particle size. A wind tunnel experiment simulating outdoor conditions showed a dependence on skin deposition velocity of wind speed, indicating that outdoor deposition velocities may be great. Both in vivo and in vitro experiments were conducted, and the influence of various factors, such as surface type, air flow, heating and electrostatics were examined. The dynamics of particle removal from human skin were studied by fluorescence scanning. This technique was also applied to estimate the fraction of aerosol dust transferred to skin by contact with a contaminated surface. The various parameters determined were applied to establish a model for calculation of radiation doses received from deposition of airborne radioactive aerosol on human body surfaces. It was found that the gamma doses from deposition on skin may be expected to be of the same order of magnitude as the gamma doses received over the first year from contamination on outdoor surfaces. According to the calculations, beta doses from skin deposition to individuals in areas of Russia, where dry deposition of Chernobyl fallout led to very high levels of contamination, may have amounted to several Sievert and may thus be responsible for a significant cancer risk. (au)

  3. The measurement of surface gravity.

    Science.gov (United States)

    Crossley, David; Hinderer, Jacques; Riccardi, Umberto

    2013-04-01

    This review covers basic theory and techniques behind the use of ground-based gravimetry at the Earth's surface. The orientation is toward modern instrumentation, data processing and interpretation for observing surface, land-based, time-variable changes to the geopotential. The instrumentation side is covered in some detail, with specifications and performance of the most widely used models of the three main types: the absolute gravimeters (FG5, A10 from Micro-g LaCoste), superconducting gravimeters (OSG, iGrav from GWR instruments), and the new generation of spring instruments (Micro-g LaCoste gPhone, Scintrex CG5 and Burris ZLS). A wide range of applications is covered, with selected examples from tides and ocean loading, atmospheric effects on gravity, local and global hydrology, seismology and normal modes, long period and tectonics, volcanology, exploration gravimetry, and some examples of gravimetry connected to fundamental physics. We show that there are only a modest number of very large signals, i.e. hundreds of µGal (10(-8) m s(-2)), that are easy to see with all gravimeters (e.g. tides, volcanic eruptions, large earthquakes, seasonal hydrology). The majority of signals of interest are in the range 0.1-5.0 µGal and occur at a wide range of time scales (minutes to years) and spatial extent (a few meters to global). Here the competing effects require a careful combination of different gravimeter types and measurement strategies to efficiently characterize and distinguish the signals. Gravimeters are sophisticated instruments, with substantial up-front costs, and they place demands on the operators to maximize the results. Nevertheless their performance characteristics such as drift and precision have improved dramatically in recent years, and their data recording ability and ruggedness have seen similar advances. Many subtle signals are now routinely connected with known geophysical effects such as coseismic earthquake displacements, post

  4. Complex chemical composition of colored surface films formed from reactions of propanal in sulfuric acid at upper troposphere/lower stratosphere aerosol acidities.

    Science.gov (United States)

    Van Wyngarden, A L; Pérez-Montaño, S; Bui, J V H; Li, E S W; Nelson, T E; Ha, K T; Leong, L; Iraci, L T

    Particles in the upper troposphere and lower stratosphere (UT/LS) consist mostly of concentrated sulfuric acid (40-80 wt %) in water. However, airborne measurements have shown that these particles also contain a significant fraction of organic compounds of unknown chemical composition. Acid-catalyzed reactions of carbonyl species are believed to be responsible for significant transfer of gas phase organic species into tropospheric aerosols and are potentially more important at the high acidities characteristic of UT/LS particles. In this study, experiments combining sulfuric acid (H 2 SO 4 ) with propanal and with mixtures of propanal with glyoxal and/or methylglyoxal at acidities typical of UT/LS aerosols produced highly colored surface films (and solutions) that may have implications for aerosol properties. In order to identify the chemical processes responsible for the formation of the surface films, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and 1 H nuclear magnetic resonance (NMR) spectroscopies were used to analyze the chemical composition of the films. Films formed from propanal were a complex mixture of aldol condensation products, acetals and propanal itself. The major aldol condensation products were the dimer (2-methyl-2-pentenal) and 1,3,5-trimethylbenzene that was formed by cyclization of the linear aldol condensation trimer. Additionally, the strong visible absorption of the films indicates that higher-order aldol condensation products must also be present as minor species. The major acetal species were 2,4,6-triethyl-1,3,5-trioxane and longer-chain linear polyacetals which are likely to separate from the aqueous phase. Films formed on mixtures of propanal with glyoxal and/or methylglyoxal also showed evidence of products of cross-reactions. Since cross-reactions would be more likely than self-reactions under atmospheric conditions, similar reactions of aldehydes like propanal with common aerosol organic species like glyoxal

  5. Volatility measurement of atmospheric submicron aerosols in an urban atmosphere in southern China

    Directory of Open Access Journals (Sweden)

    L.-M. Cao

    2018-02-01

    Full Text Available Aerosol pollution has been a very serious environmental problem in China for many years. The volatility of aerosols can affect the distribution of compounds in the gas and aerosol phases, the atmospheric fates of the corresponding components, and the measurement of the concentration of aerosols. Compared to the characterization of chemical composition, few studies have focused on the volatility of aerosols in China. In this study, a thermodenuder aerosol mass spectrometer (TD-AMS system was deployed to study the volatility of non-refractory submicron particulate matter (PM1 species during winter in Shenzhen. To our knowledge, this paper is the first report of the volatilities of aerosol chemical components based on a TD-AMS system in China. The average PM1 mass concentration during the experiment was 42.7±20.1 µg m−3, with organic aerosol (OA being the most abundant component (43.2 % of the total mass. The volatility of chemical species measured by the AMS varied, with nitrate showing the highest volatility, with a mass fraction remaining (MFR of 0.57 at 50 °C. Organics showed semi-volatile characteristics (the MFR was 0.88 at 50 °C, and the volatility had a relatively linear correlation with the TD temperature (from the ambient temperature to 200 °C, with an evaporation rate of 0.45 % °C−1. Five subtypes of OA were resolved from total OA using positive matrix factorization (PMF for data obtained under both ambient temperature and high temperatures through the TD, including a hydrocarbon-like OA (HOA, accounting for 13.5 %, a cooking OA (COA, 20.6 %, a biomass-burning OA (BBOA, 8.9 %, and two oxygenated OAs (OOAs: a less-oxidized OOA (LO-OOA, 39.1 % and a more-oxidized OOA (MO-OOA, 17.9 %. Different OA factors presented different volatilities, and the volatility sequence of the OA factors at 50 °C was HOA (MFR of 0.56  >  LO-OOA (0.70  >  COA (0.85  ≈  BBOA (0.87

  6. Measurement of an electronic cigarette aerosol size distribution during a puff

    Directory of Open Access Journals (Sweden)

    Belka Miloslav

    2017-01-01

    Full Text Available Electronic cigarettes (e-cigarettes have become very popular recently because they are marketed as a healthier alternative to tobacco smoking and as a useful tool to smoking cessation. E-cigarettes use a heating element to create an aerosol from a solution usually consisting of propylene glycol, glycerol, and nicotine. Despite the wide spread of e-cigarettes, information about aerosol size distributions is rather sparse. This can be caused by the relative newness of e-cigarettes and by the difficulty of the measurements, in which one has to deal with high concentration aerosol containing volatile compounds. Therefore, we assembled an experimental setup for size measurements of e-cigarette aerosol in conjunction with a piston based machine in order to simulate a typical puff. A TSI scanning mobility particle sizer 3936 was employed to provide information about particle concentrations and sizes. An e-cigarette commercially available on the Czech Republic market was tested and the results were compared with a conventional tobacco cigarette. The particles emitted from the e-cigarette were smaller than those of the conventional cigarette having a CMD of 150 and 200 nm. However, the total concentration of particles from e-cigarette was higher.

  7. Measurement of an electronic cigarette aerosol size distribution during a puff

    Science.gov (United States)

    Belka, Miloslav; Lizal, Frantisek; Jedelsky, Jan; Jicha, Miroslav; Pospisil, Jiri

    Electronic cigarettes (e-cigarettes) have become very popular recently because they are marketed as a healthier alternative to tobacco smoking and as a useful tool to smoking cessation. E-cigarettes use a heating element to create an aerosol from a solution usually consisting of propylene glycol, glycerol, and nicotine. Despite the wide spread of e-cigarettes, information about aerosol size distributions is rather sparse. This can be caused by the relative newness of e-cigarettes and by the difficulty of the measurements, in which one has to deal with high concentration aerosol containing volatile compounds. Therefore, we assembled an experimental setup for size measurements of e-cigarette aerosol in conjunction with a piston based machine in order to simulate a typical puff. A TSI scanning mobility particle sizer 3936 was employed to provide information about particle concentrations and sizes. An e-cigarette commercially available on the Czech Republic market was tested and the results were compared with a conventional tobacco cigarette. The particles emitted from the e-cigarette were smaller than those of the conventional cigarette having a CMD of 150 and 200 nm. However, the total concentration of particles from e-cigarette was higher.

  8. A review of optical measurements at the aerosol and cloud chamber AIDA

    International Nuclear Information System (INIS)

    Wagner, Robert; Linke, Claudia; Naumann, Karl-Heinz; Schnaiter, Martin; Vragel, Marlen; Gangl, Martin; Horvath, Helmuth

    2009-01-01

    This paper provides a survey of recent studies on the optical properties of aerosol and cloud particles that have been conducted at the AIDA facility of Forschungszentrum Karlsruhe (Aerosol Interactions and Dynamics in the Atmosphere). Reflecting the broad accessible temperature range of the AIDA chamber which extends from ambient temperature down to 183 K, the investigations feature a broad diversity of research topics, such as the wavelength-dependence of the specific absorption cross sections of soot and mineral dust aerosols at room temperature, depolarization and infrared extinction measurements of ice crystal clouds generated at temperatures below 235 K, and the optical properties of polar stratospheric cloud constituents whose formation was studied in chamber experiments at temperatures well below 200 K. After reviewing the AIDA research activity of the past decade and introducing the optical instrumentation of the AIDA facility, this paper presents illustrative examples of ongoing and already published work on optical measurements of soot aerosols, mineral dust particles, and ice crystal clouds.

  9. Towards routine measurements of meteorological and aerosol parameters using small unmanned aerial and tethered balloon systems

    Science.gov (United States)

    Mei, F.; Dexheimer, D.; Hubbe, J. M.; deBoer, G.; Schmid, B.; Ivey, M.; Longbottom, C.; Carroll, P.

    2017-12-01

    The Inaugural Campaigns for ARM Research using Unmanned Systems (ICARUS) had been launched in 2016 and then the effort has been continued in 2017. ICARUS centered on Oliktok Point, Alaska focusses on developing routine operations of Unmanned Aerial Systems (UAS) and Tethered Balloon Systems (TBS). The operation routine practiced during ICARUS 2016 provided valuable guidance for the ICARUS 2017 deployment. During two intensive operation periods in 2017, a small DataHawk II UAS has been deployed to collect data for two weeks each in May and August. Coordinated with DataHawk flights, the TBS has been launched with meteorology sensors such as iMet and Tethersondes, therefore vertical profiles of the basic atmospheric state (temperature, humidity, and horizontal wind) were observed simultaneously by UAS and TBS. In addition, an aerosol payload was attached and launched with 2 TBS flights in April and 7 TBS flights in May, which include a condensation particle counter (CPC, TSI 3007) and two printed optical particle spectrometers (POPS, Handix TBS version). The two POPS were operated at different inlet temperatures. This approach provided potential measurements for aerosol optical closure in future. Measured aerosol properties include total particle number concentrations, particle size distribution, at different ambient temperature and relative humidity. Vertical profiles of atmospheric state and aerosol properties will be discussed based on the coordinated flights. Monthly variation will be assessed with data from the upcoming August flights.

  10. Inferring brown carbon content from UV aerosol absorption measurements during biomass burning season

    Science.gov (United States)

    Mok, J.; Krotkov, N. A.; Arola, A. T.; Torres, O.; Jethva, H. T.; Andrade, M.; Labow, G. J.; Eck, T. F.; Li, Z.; Dickerson, R. R.; Stenchikov, G. L.; Osipov, S.

    2015-12-01

    Measuring spectral dependence of light absorption by colored organic or "brown" carbon (BrC) is important, because of its effects on photolysis rates of ozone and surface ultraviolet (UV) radiation. Enhanced UV spectral absorption by BrC can in turn be exploited for simultaneous retrievals of BrC and black carbon (BC) column amounts in field campaigns. We present an innovative ground-based retrieval of BC and BrC volume fractions and their mass absorption efficiencies during the biomass burning season in Santa Cruz, Bolivia in September-October 2007. Our method combines retrieval of BC volume fraction using AERONET inversion in visible wavelengths with the inversion of total BC+BrC absorption (i.e., column effective imaginary refractive index, kmeas) using Diffuse/Direct irradiance measurements in UV wavelengths. First, we retrieve BrC volume fraction by fitting kmeas at 368nm using Maxwell-Garnett (MG) mixing rules assuming: (1) flat spectral dependence of kBC, (2) known value of kBrC at 368nm from laboratory absorption measurements or smoke chamber experiments, and (3) known BC volume fraction from AERONET inversion. Next, we derive kBrC in short UVB wavelengths by fitting kmeas at 305nm, 311nm, 317nm, 325nm, and 332nm using MG mixing rules and fixed volume fractions of BC and BrC. Our retrievals show larger than expected spectral dependence of kBrC in UVB wavelengths, implying reduced surface UVB irradiance and inhibited photolysis rates of surface ozone destruction. We use a one-dimensional chemical box model to show that the observed strong wavelength dependence of BrC absorption leads to inhibited photolysis of ozone to O(1D), a loss mechanism, while having little impact or even accelerating photolysis of NO2, an ozone production mechanism. Although BC only absorption in biomass burning aerosols is important for climate radiative forcing in the visible wavelengths, additional absorption by BrC is important because of its impact on surface UVB radiation

  11. Chemical composition of aerosol measurements in the air pollution plume during KORUS-AQ

    Science.gov (United States)

    Park, T.; Lee, J. B.; Lim, Y. J.; Ahn, J.; Park, J. S.; Soo, C. J.; Kim, J.; Park, S.; Lee, Y.; Desyaterik, Y.; Collett, J. L., Jr.; Lee, T.

    2017-12-01

    The Korean peninsula is a great place to study different sources of the aerosols: urban, rural and marine. In addition, Seoul is one of the large metropolitan areas in the world and has a variety of sources because half of the Korean population lives in Seoul, which comprises only 12% of the country's area. To understand the chemical composition of aerosol form long-range transport and local sources better, an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed on an airborne platform (NASA DC-8 aircraft). The HR-ToF-AMS is capable of measuring non-refractory size resolved chemical composition of submicron particle(NR-PM1) in the air pollution plume, including mass concentration of organic carbon, nitrate, sulfate, and ammonium with 10 seconds time resolution. The measurements were performed twenty times research flight for understanding characteristic of the air pollution from May to June, 2016 on the South Korean peninsula during KORUS-AQ 2016 campaign. The scientific goal of this study is to characterize aerosol chemical properties and mass concentration in order to understand the role of the long-range transport from northeast Asia to South Korea, and influence of the local sources. To brief, organics dominated during all of flights. Also, organics and nitrate were dominant around energy industrial complex near by Taean, South Korea. The presentation will provide an overview of the composition of NR-PM1 measured in air pollution plumes, and deliver detail information about width, depth and spatial distribution of the pollutant in the air pollution plumes. The results of this study will provide high temporal and spatial resolved details on the air pollution plumes, which are valuable input parameters of aerosol properties for the current air quality models.

  12. Heterogeneous conversion of NO2 on secondary organic aerosol surfaces: A possible source of nitrous acid (HONO in the atmosphere?

    Directory of Open Access Journals (Sweden)

    R. Bröske

    2003-01-01

    Full Text Available The heterogeneous conversion of NO2 on different secondary organic aerosols (SOA was investigated with the focus on a possible formation of nitrous acid (HONO. In one set of experiments different organic aerosols were produced in the reactions of O3 with alpha-pinene, limonene or catechol and OH radicals with toluene or limonene, respectively. The aerosols were sampled on filters and exposed to humidified NO2  mixtures under atmospheric conditions. The estimated upper limits for the uptake coefficients of NO2  and the reactive uptake coefficients NO2  -> HONO are in the range of 10-6 and 10-7, respectively. The integrated HONO formation for 1 h reaction time was 13 cm-2 geometrical surface and 17 g-1 particle mass. In a second set of experiments the conversion of NO2 into HONO in the presence of organic particles was carried out in an aerosol flow tube under atmospheric conditions. In this case the aerosols were produced in the reaction of O3 with beta-pinene, limonene or catechol, respectively. The upper limits for the reactive uptake coefficients NO2 -> HONO were in the range of 7 x 10-7 - 9 x 10-6. The results from the present study show that heterogeneous formation of nitrous acid on secondary organic aerosols (SOA is unimportant for the atmosphere.

  13. Glutathione aerosol suppresses lung epithelial surface inflammatory cell-derived oxidants in cystic fibrosis.

    Science.gov (United States)

    Roum, J H; Borok, Z; McElvaney, N G; Grimes, G J; Bokser, A D; Buhl, R; Crystal, R G

    1999-07-01

    Cystic fibrosis (CF) is characterized by accumulation of activated neutrophils and macrophages on the respiratory epithelial surface (RES); these cells release toxic oxidants, which contribute to the marked epithelial derangements seen in CF. These deleterious consequences are magnified, since reduced glutathione (GSH), an antioxidant present in high concentrations in normal respiratory epithelial lining fluid (ELF), is deficient in CF ELF. To evaluate the feasibility of increasing ELF GSH levels and enhancing RES antioxidant protection, GSH aerosol was delivered (600 mg twice daily for 3 days) to seven patients with CF. ELF total, reduced, and oxidized GSH increased (P < 0.05, all compared with before GSH therapy), suggesting adequate RES delivery and utilization of GSH. Phorbol 12-myristate 13-acetate-stimulated superoxide anion (O2-.) release by ELF inflammatory cells decreased after GSH therapy (P < 0.002). This paralleled observations that GSH added in vitro to CF ELF inflammatory cells suppressed O2-. release (P < 0.001). No adverse effects were noted during treatment. Together, these observations demonstrate the feasibility of using GSH aerosol to restore RES oxidant-antioxidant balance in CF and support the rationale for further clinical evaluation.

  14. Column Aerosol Optical Properties and Aerosol Radiative Forcing During a Serious Haze-Fog Month over North China Plain in 2013 Based on Ground-Based Sunphotometer Measurements

    Science.gov (United States)

    Che, H.; Xia, X.; Zhu, J.; Li, Z.; Dubovik, O.; Holben, Brent N.; Goloub, P.; Chen, H.; Estelles, V.; Cuevas-Agullo, E.

    2014-01-01

    In January 2013, North China Plain experienced several serious haze events. Cimel sunphotometer measurements at seven sites over rural, suburban and urban regions of North China Plain from 1 to 30 January 2013 were used to further our understanding of spatial-temporal variation of aerosol optical parameters and aerosol radiative forcing (ARF). It was found that Aerosol Optical Depth at 500 nm (AOD500nm) during non-pollution periods at all stations was lower than 0.30 and increased significantly to greater than 1.00 as pollution events developed. The Angstrom exponent (Alpha) was larger than 0.80 for all stations most of the time. AOD500nm averages increased from north to south during both polluted and non-polluted periods on the three urban sites in Beijing. The fine mode AOD during pollution periods is about a factor of 2.5 times larger than that during the non-pollution period at urban sites but a factor of 5.0 at suburban and rural sites. The fine mode fraction of AOD675nm was higher than 80% for all sites during January 2013. The absorption AOD675nm at rural sites was only about 0.01 during pollution periods, while 0.03-0.07 and 0.01-0.03 during pollution and non-pollution periods at other sites, respectively. Single scattering albedo varied between 0.87 and 0.95 during January 2013 over North China Plain. The size distribution showed an obvious tri-peak pattern during the most serious period. The fine mode effective radius in the pollution period was about 0.01-0.08 microns larger than during nonpollution periods, while the coarse mode radius in pollution periods was about 0.06-0.38 microns less than that during nonpollution periods. The total, fine and coarse mode particle volumes varied by about 0.06-0.34 cu microns, 0.03-0.23 cu microns, and 0.03-0.10 cu microns, respectively, throughout January 2013. During the most intense period (1-16 January), ARF at the surface exceeded -50W/sq m, -180W/sq m, and -200W/sq m at rural, suburban, and urban sites

  15. Advancing Solar Irradiance Measurement for Climate-Related Studies: Accurate Constraint on Direct Aerosol Radiative Effect (DARE)

    Science.gov (United States)

    Tsay, Si-Chee; Ji, Q. Jack

    2011-01-01

    Earth's climate is driven primarily by solar radiation. As summarized in various IPCC reports, the global average of radiative forcing for different agents and mechanisms, such as aerosols or CO2 doubling, is in the range of a few W/sq m. However, when solar irradiance is measured by broadband radiometers, such as the fleet of Eppley Precision Solar Pyranometers (PSP) and equivalent instrumentation employed worldwide, the measurement uncertainty is larger than 2% (e.g., WMO specification of pyranometer, 2008). Thus, out of the approx. 184 W/sq m (approx.263 W/sq m if cloud-free) surface solar insolation (Trenberth et al. 2009), the measurement uncertainty is greater than +/-3.6 W/sq m, overwhelming the climate change signals. To discern these signals, less than a 1 % measurement uncertainty is required and is currently achievable only by means of a newly developed methodology employing a modified PSP-like pyranometer and an updated calibration equation to account for its thermal effects (li and Tsay, 2010). In this talk, we will show that some auxiliary measurements, such as those from a collocated pyrgeometer or air temperature sensors, can help correct historical datasets. Additionally, we will also demonstrate that a pyrheliometer is not free of the thermal effect; therefore, comparing to a high cost yet still not thermal-effect-free "direct + diffuse" approach in measuring surface solar irradiance, our new method is more economical, and more likely to be suitable for correcting a wide variety of historical datasets. Modeling simulations will be presented that a corrected solar irradiance measurement has a significant impact on aerosol forcing, and thus plays an important role in climate studies.

  16. Measurements of non-volatile aerosols with a VTDMA and their correlations with carbonaceous aerosols in Guangzhou, China

    Science.gov (United States)

    Cheung, Heidi H. Y.; Tan, Haobo; Xu, Hanbing; Li, Fei; Wu, Cheng; Yu, Jian Z.; Chan, Chak K.

    2016-07-01

    Simultaneous measurements of aerosol volatility and carbonaceous matters were conducted at a suburban site in Guangzhou, China, in February and March 2014 using a volatility tandem differential mobility analyzer (VTDMA) and an organic carbon/elemental carbon (OC / EC) analyzer. Low volatility (LV) particles, with a volatility shrink factor (VSF) at 300 °C exceeding 0.9, contributed 5 % of number concentrations of the 40 nm particles and 11-15 % of the 80-300 nm particles. They were composed of non-volatile material externally mixed with volatile material, and therefore did not evaporate significantly at 300 °C. Non-volatile material mixed internally with the volatile material was referred to as medium volatility (MV, 0.4 transported at low altitudes (below 1500 m) for over 40 h before arrival. Further comparison with the diurnal variations in the mass fractions of EC and the non-volatile OC in PM2.5 suggests that the non-volatile residuals may be related to both EC and non-volatile OC in the afternoon, during which the concentration of aged organics increased. A closure analysis of the total mass of LV and MV residuals and the mass of EC or the sum of EC and non-volatile OC was conducted. It suggests that non-volatile OC, in addition to EC, was one of the components of the non-volatile residuals measured by the VTDMA in this study.

  17. Simultaneous determination of aerosol optical thickness and water-leaving radiance from multispectral measurements in coastal waters

    Science.gov (United States)

    Shi, Chong; Nakajima, Teruyuki

    2018-03-01

    Retrieval of aerosol optical properties and water-leaving radiance over ocean is challenging since the latter mostly accounts for ˜ 10 % of the satellite-observed signal and can be easily influenced by the atmospheric scattering. Such an effort would be more difficult in turbid coastal waters due to the existence of optically complex oceanic substances or high aerosol loading. In an effort to solve such problems, we present an optimization approach for the simultaneous determination of aerosol optical thickness (AOT) and normalized water-leaving radiance (nLw) from multispectral satellite measurements. In this algorithm, a coupled atmosphere-ocean radiative transfer model combined with a comprehensive bio-optical oceanic module is used to jointly simulate the satellite-observed reflectance at the top of atmosphere and water-leaving radiance just above the ocean surface. Then, an optimal estimation method is adopted to retrieve AOT and nLw iteratively. The algorithm is validated using Aerosol Robotic Network - Ocean Color (AERONET-OC) products selected from eight OC sites distributed over different waters, consisting of observations that covered glint and non-glint conditions from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. Results show a good consistency between retrieved and in situ measurements at each site. It is demonstrated that more accurate AOTs are determined based on the simultaneous retrieval method, particularly in shorter wavelengths and sunglint conditions, where the averaged percentage difference (APD) of retrieved AOT is generally reduced by approximate 10 % in visible bands compared with those derived from the standard atmospheric correction (AC) scheme, since all the spectral measurements can be used jointly to increase the information content in the inversion of AOT, and the wind speed is also simultaneously retrieved to compensate the specular reflectance error estimated from the rough ocean surface model. For the

  18. An analytical solution to calculate bulk mole fractions for any number of components in aerosol droplets after considering partitioning to a surface layer

    Directory of Open Access Journals (Sweden)

    D. Topping

    2010-11-01

    Full Text Available Calculating the equilibrium composition of atmospheric aerosol particles, using all variations of Köhler theory, has largely assumed that the total solute concentrations define both the water activity and surface tension. Recently however, bulk to surface phase partitioning has been postulated as a process which significantly alters the predicted point of activation. In this paper, an analytical solution to calculate the removal of material from a bulk to a surface layer in aerosol particles has been derived using a well established and validated surface tension framework. The applicability to an unlimited number of components is possible via reliance on data from each binary system. Whilst assumptions regarding behaviour at the surface layer have been made to facilitate derivation, it is proposed that the framework presented can capture the overall impact of bulk-surface partitioning. Demonstrations of the equations for two and five component mixtures are given while comparisons are made with more detailed frameworks capable at modelling ternary systems at higher levels of complexity. Predictions made by the model across a range of surface active properties should be tested against measurements. Indeed, reccomendations are given for experimental validation and to assess sensitivities to accuracy and required level of complexity within large scale frameworks. Importantly, the computational efficiency of using the solution presented in this paper is roughly a factor of 20 less than a similar iterative approach, a comparison with highly coupled approaches not available beyond a 3 component system.

  19. Aerosol Hygroscopicity Distribution and Mixing State Determined by Cloud Condensation Nuclei (CCN) Measurements

    Science.gov (United States)

    Su, H.; Rose, D.; Cheng, Y.; Gunthe, S. S.; Wiedensohler, A.; Andreae, M. O.; Pöschl, U.

    2009-12-01

    This paper presents, firstly the concept of hygroscopicity distribution and its application in the analysis of cloud condensation nuclei (CCN) measurement data. The cumulative particle hygroscopicity distribution function N(κ) is defined as the number concentration of particles with a hygroscopicity parameter, κ, smaller than a certain value of κ. Since the measured CCN (at supersaturation S) can be considered as those particles with κ larger than a certain value, the CCN efficiency spectra (activation curve) can be easily converted to N(κ) distributions. Unlike studies calculating only one hygroscopicity parameter from a CCN activation curve, the concept of N(κ) shows the usefulness of all points on the activation curve. Modeling studies of three assumed N(κ) distributions are used to illustrate the new concept N(κ) and how it is related to the size-resolved CCN measurements. Secondly, we discuss the aerosol mixing state information that can be obtained from the shape of N(κ). A case study is performed based on the CCN measurements during the CAREBEIJING 2006 campaign. In the campaign-averaged N(κ) distribution, most particles (>80%) lie in a mode with a geometric mean κ around 0.2-0.4, and an increasing trend in the mean κ is found as particle size increases. There seems to be another less hygroscopic mode but the κ resolution (depending on the size resolution) in the campaign is not high enough to interpret it. It is also clear that N(κ) is not a monodisperse distribution (implying an internal mixture of the aerosols). The dispersion parameter σg,κ, which is the geometric standard deviation of N(κ), can be used as an indicator for the aerosol mixing state. The indicator σg,κ shows good agreement with the soot mixing state measured by a volatility tandem differential mobility analyzer (VTDMA) during the CAREBEIJING 2006 campaign. The concept of N(κ) can be widely used to study aerosol mixing states, especially in the lab experiment where a

  20. Disentangling sea-surface temperature and anthropogenic aerosol influences on recent trends in South Asian monsoon rainfall

    Science.gov (United States)

    Patil, Nitin; Venkataraman, Chandra; Muduchuru, Kaushik; Ghosh, Subimal; Mondal, Arpita

    2018-05-01

    Recent studies point to combined effects of changes in regional land-use, anthropogenic aerosol forcing and sea surface temperature (SST) gradient on declining trends in the South Asian monsoon (SAM). This study attempted disentangling the effects produced by changes in SST gradient from those by aerosol levels in an atmospheric general circulation model. Two pairs of transient ensemble simulations were made, for a 40-year period from 1971 to 2010, with evolving versus climatological SSTs and with anthropogenic aerosol emissions fixed at 1971 versus 2010, in each case with evolution of the other forcing element, as well as GHGs. Evolving SST was linked to a widespread feedback on increased surface temperature, reduced land-sea thermal contrast and a weakened Hadley circulation, with weakening of cross-equatorial transport of moisture transport towards South Asia. Increases in anthropogenic aerosol levels (1971 versus 2010), led to an intensification of drying in the peninsular Indian region, through several regional pathways. Aerosol forcing induced north-south asymmetries in temperature and sea-level pressure response, and a cyclonic circulation in the Bay of Bengal, leading to an easterly flow, which opposes the monsoon flow, suppressing moisture transport over peninsular India. Further, aerosol induced decreases in convection, vertically integrated moisture flux convergence, evaporation flux and cloud fraction, in the peninsular region, were spatially congruent with reduced convective and stratiform rainfall. Overall, evolution of SST acted through a weakening of cross-equatorial moisture flow, while increases in aerosol levels acted through suppression of Arabian Sea moisture transport, as well as, of convection and vertical moisture transport, to influence the suppression of SAM rainfall.

  1. 403 nm cavity ring-down measurements of brown carbon aerosol

    Science.gov (United States)

    Kwon, D.; Grassian, V. H.; Kleiber, P.; Young, M. A.

    2017-12-01

    Atmospheric aerosol influences Earth's climate by absorbing and scattering incoming solar radiation and outgoing terrestrial radiation. One class of secondary organic aerosol (SOA), called brown carbon (BrC), has attracted attention for its wavelength dependent light absorbing properties with absorption coefficients that generally increase from the visible (Vis) to ultraviolet (UV) regions. Here we report results from our investigation of the optical properties of BrC aerosol products from the aqueous phase reaction of ammonium sulfate (AS) with methylglyoxal (MG) using cavity ring-down spectroscopy (CRDS) at 403 nm wavelength. We have measured the optical constants of BrC SOA from the AS/MG reaction as a function of reaction time. Under dry flow conditions, we observed no apparent variation in the BrC refractive index with aging over the course of 22 days. The retrieved BrC optical constants are similar to those of AS with n = 1.52 for the real component. Despite significant UV absorption observed from the bulk BrC solution, the imaginary index value at 403 nm is below our minimum detection limit which puts an upper bound of k as 0.03. These observations are in agreement with results from our recent studies of the light scattering properties of this BrC aerosol.

  2. Daily and seasonal variation of aerosol concentration in the atmosphere near the surface in continental climate of Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Koutsenogii, P [Inst. of Chemical Kinetics and Combustion, Novosibirsk (Russian Federation)

    1996-12-31

    Novosibirsk region is the area in southern part of West-Siberian lowland, covering about 200,000 km{sup 2}. The properties of atmospheric aerosol in Novosibirsk region were studied during few campaigns in the years 1992 and 1993, one complex expedition in Summer of 1994 and durable observations in Akademgorodok in the years 1993, 1994. Akademgorodok is situated 25 km S from the city Novosibirsk, has population of about 100,000 and no industry. Three different locations in remote areas of Novosibirsk region were used for the measurements. The first was situated 12 km E from Akademgorodok, and 30 km from Novosibirsk near the village Kljutchi. The second location was situated close to Lake Tchany in western part of Novosibirsk region. The third location was situated in south-western part of Novosibirsk region, 12 km from the town Karasuk. The total aerosol light scattering by aerosol particles was measured by commercially available nephelometer FAN-A in terms of units, related to the molecular scattering of clean air, measured by the same nephelometer. Aerosol samples in which the content of sulfate-, nitrate-, and cloride-anions was determined, using ion liquid chromatography, were collected with Whatman 41 or AFA-HA filters. Aerosol mass concentration was measured by weighting of AFA-HA filters. Aerosol particles were sampled on the filters with the volume velocity of about 500 l/min for Whatman 41 and 120 l/min for AFA-HA and mean sampling duration of 24 hours. The total aerosol number concentration was measured with a condensation nuclei counter TSI 3020

  3. Daily and seasonal variation of aerosol concentration in the atmosphere near the surface in continental climate of Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Koutsenogii, P. [Inst. of Chemical Kinetics and Combustion, Novosibirsk (Russian Federation)

    1995-12-31

    Novosibirsk region is the area in southern part of West-Siberian lowland, covering about 200,000 km{sup 2}. The properties of atmospheric aerosol in Novosibirsk region were studied during few campaigns in the years 1992 and 1993, one complex expedition in Summer of 1994 and durable observations in Akademgorodok in the years 1993, 1994. Akademgorodok is situated 25 km S from the city Novosibirsk, has population of about 100,000 and no industry. Three different locations in remote areas of Novosibirsk region were used for the measurements. The first was situated 12 km E from Akademgorodok, and 30 km from Novosibirsk near the village Kljutchi. The second location was situated close to Lake Tchany in western part of Novosibirsk region. The third location was situated in south-western part of Novosibirsk region, 12 km from the town Karasuk. The total aerosol light scattering by aerosol particles was measured by commercially available nephelometer FAN-A in terms of units, related to the molecular scattering of clean air, measured by the same nephelometer. Aerosol samples in which the content of sulfate-, nitrate-, and cloride-anions was determined, using ion liquid chromatography, were collected with Whatman 41 or AFA-HA filters. Aerosol mass concentration was measured by weighting of AFA-HA filters. Aerosol particles were sampled on the filters with the volume velocity of about 500 l/min for Whatman 41 and 120 l/min for AFA-HA and mean sampling duration of 24 hours. The total aerosol number concentration was measured with a condensation nuclei counter TSI 3020

  4. Increase of surface solar irradiance across East China related to changes in aerosol properties during the past decade

    Science.gov (United States)

    Li, Jing; Jiang, Yiwei; Xia, Xiangao; Hu, Yongyun

    2018-03-01

    Previously, it was widely documented that an overall decrease in surface solar radiation occurred in China at least until 2005, in contrast to the general background of ‘global brightening’. Increased anthropogenic aerosol emissions were speculated to be the source of the reduction. In this study, we extend the trend analysis to the most recent decade from 2005-2015 and find that surface solar radiation has shifted from ‘dimming’ to ‘brightening’ over East China, with the largest increase over the northeast and southeast parts. Meanwhile, satellite and ground observation both indicate a reduction in aerosol optical depth (AOD) during the same period, whereas no significant trends in cloud amount show up. Detailed analysis using co-located radiation and aerosol observation at the XiangHe station in North China suggests that both AOD and single scattering albedo (SSA) changes contribute to the radiation trends. AOD reduction contributes to the increase of direct solar radiation, also decreasing the diffuse radiation, while the increase of SSA serves to increase the diffuse fraction. Simple calculations using a radiative transfer model confirm that the two effects combined explain changes in the global solar radiation and its components effectively. Our results have implications for potential climate effects with the reduction of China’s aerosol emissions, and the necessity to monitor aerosol composition in addition to its loading.

  5. An inverse modeling procedure to determine particle growth and nucleation rates from measured aerosol size distributions

    Directory of Open Access Journals (Sweden)

    B. Verheggen

    2006-01-01

    Full Text Available Classical nucleation theory is unable to explain the ubiquity of nucleation events observed in the atmosphere. This shows a need for an empirical determination of the nucleation rate. Here we present a novel inverse modeling procedure to determine particle nucleation and growth rates based on consecutive measurements of the aerosol size distribution. The particle growth rate is determined by regression analysis of the measured change in the aerosol size distribution over time, taking into account the effects of processes such as coagulation, deposition and/or dilution. This allows the growth rate to be determined with a higher time-resolution than can be deduced from inspecting contour plots ('banana-plots''. Knowing the growth rate as a function of time enables the evaluation of the time of nucleation of measured particles of a certain size. The nucleation rate is then obtained by integrating the particle losses from time of measurement to time of nucleation. The regression analysis can also be used to determine or verify the optimum value of other parameters of interest, such as the wall loss or coagulation rate constants. As an example, the method is applied to smog chamber measurements. This program offers a powerful interpretive tool to study empirical aerosol population dynamics in general, and nucleation and growth in particular.

  6. GRIP LANGLEY AEROSOL RESEARCH GROUP EXPERIMENT (LARGE) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — Langley Aerosol Research Group Experiment (LARGE) measures ultrafine aerosol number density, total and non-volatile aerosol number density, dry aerosol size...

  7. Mass transfer effects in hygroscopic measurements of aerosol particles

    Directory of Open Access Journals (Sweden)

    M. N. Chan

    2005-01-01

    Full Text Available The tandem differential mobility analyzer (TDMA has been widely utilized to measure the hygroscopicity of laboratory-generated and atmospheric submicrometer particles. An important concern in investigating the hygroscopicity of the particles is if the particles have attained equilibrium state in the measurements. We present a literature survey to investigate the mass transfer effects in hygroscopicity measurements. In most TDMA studies, a residence time in the order of seconds is used for humidification (or dehumidification. NaCl and (NH42SO4 particles are usually used to verify the equilibrium measurements during this residence time, which is presumed to be sufficient for other particles. There have been observations that not all types of submicrometer particles, including atmospheric particles, attain their equilibrium sizes within this time scale. We recommend that experimentation with different residence times be conducted and that the residence time should be explicitly stated in future TDMA measurements. Mass transfer effects may also exist in the measurements of other properties related to the water uptake of atmospheric particles such as relative humidity dependent light scattering coefficients and cloud condensation nuclei activity.

  8. Airborne spectral measurements of surface anisotropy during SCAR-B

    Science.gov (United States)

    Tsay, Si-Chee; King, Michael D.; Arnold, G. Thomas; Li, Jason Y.

    1998-12-01

    During the Smoke, Clouds, and Radiation-Brazil (SCAR-B) deployment, angular distributions of spectral reflectance for vegetated surfaces and smoke layers were measured using the scanning cloud absorption radiometer (CAR) mounted on the University of Washington C-131A research aircraft. The CAR contains 13 narrowband spectral channels between 0.3 and 2.3 μm with a 190° scan aperture (5° before zenith to 5° past nadir) and 1° instantaneous field of view. The bidirectional reflectance is obtained by flying a clockwise circular orbit above the surface, resulting in a ground track ˜3 km in diameter within about 2 min. Although the CAR measurements are contaminated by minor atmospheric effects, results show distinct spectral characteristics for various types of surfaces. Spectral bidirectional reflectances of three simple and well-defined surfaces are presented: cerrado (August 18, 1995) and dense forest (August 25, 1995), both measured in Brazil under nearly clear-sky conditions, and thick smoke layers over dense forest (September 6 and 11, 1995). The bidirectional reflectances of cerrado and dense forest revealed fairly symmetric patterns along the principal plane, with varying maximal strengths and widths spectrally in the backscattering direction. In the shortwave-infrared region the aerosol effect is very small due to low spectral optical depth. Also, these backscattering maxima can be seen on the bidirectional reflectance of smoke layer over dense forest. These detailed measurements of the angular distribution of spectral reflectance can be parameterized by a few independent variables and utilized to retrieve either surface characteristics or aerosol microphysical and optical properties (e.g., size distribution and single-scattering parameters), if proper physical and radiation models are used. The spectral-hemispherical albedo of these surfaces is obtained directly by integrating all angular measurements and is compared with the measured nadir reflectance

  9. Interpreting aerosol lifetimes using the GEOS-Chem model and constraints from radionuclide measurements

    Energy Technology Data Exchange (ETDEWEB)

    Croft, B. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Pierce, J.R. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Colorado State Univ., Fort Collins, CO (United States); Martin, R.V. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

    2014-07-01

    Aerosol removal processes control global aerosol abundance, but the rate of that removal remains uncertain. A recent study of aerosol-bound radionuclide measurements after the Fukushima Daiichi nuclear power plant accident documents {sup 137}Cs removal (e-folding) times of 10.0-13.9 days, suggesting that mean aerosol lifetimes in the range of 3-7 days in global models might be too short by a factor of two. In this study, we attribute this discrepancy to differences between the e-folding and mean aerosol lifetimes. We implement a simulation of {sup 137}Cs and {sup 133}Xe into the GEOS-Chem chemical transport model and examine the removal rates for the Fukushima case. We find a general consistency between modelled and measured e-folding times. The simulated {sup 137}Cs global burden e-folding time is about 14 days. However, the simulated mean lifetime of aerosol-bound {sup 137}Cs over a 6-month post-accident period is only 1.8 days. We find that the mean lifetime depends strongly on the removal rates in the first few days after emissions, before the aerosols leave the boundary layer and are transported to altitudes and latitudes where lifetimes with respect to wet removal are longer by a few orders of magnitude. We present sensitivity simulations that demonstrate the influence of differences in altitude and location of the radionuclides on the mean lifetime. Global mean lifetimes are shown to strongly depend on the altitude of injection. The global mean {sup 137}Cs lifetime is more than one order of magnitude greater for the injection at 7 km than into the boundary layer above the Fukushima site. Instantaneous removal rates are slower during the first few days after the emissions for a free tropospheric versus boundary layer injection and this strongly controls the mean lifetimes. Global mean aerosol lifetimes for the GEOS-Chem model are 3-6 days, which is longer than that for the {sup 137}Cs injected at the Fukushima site (likely due to precipitation shortly after

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  11. Highly-controlled, reproducible measurements of aerosol emissions from African biomass combustion

    Science.gov (United States)

    Haslett, Sophie; Thomas, J. Chris; Morgan, William; Hadden, Rory; Liu, Dantong; Allan, James; Williams, Paul; Sekou, Keïta; Liousse, Catherine; Coe, Hugh

    2017-04-01

    Particulate emissions from biomass burning can alter the atmosphere's radiative balance and cause significant harm to human health. However, the relationship between these emissions and fundamental combustion processes is, to date, poorly characterised. In atmospheric models, aerosol emissions are represented by emission factors based on mass loss, which are averaged over an entire combustion event for each particulate species. This approach, however, masks huge variability in emissions during different phases of the combustion period. Laboratory tests have shown that even small changes to the burning environment can lead to huge variation in observed aerosol emission factors (Akagi et al., 2011). In order to address this gap in understanding, in this study, small wood samples sourced from Côte D'Ivoire were burned in a highly-controlled laboratory environment. The shape and mass of samples, available airflow and surrounding heat were carefully regulated. Organic aerosol and refractory black carbon emissions were measured in real-time using an Aerosol Mass Spectrometer and a Single Particle Soot Photometer, respectively. Both of these instruments are used regularly to measure aerosol concentrations in the field. This methodology produced remarkably repeatable results, allowing three different phases of combustion to be identified by their emissions. Black carbon was emitted predominantly during flaming combustion; organic aerosols were emitted during pyrolysis before ignition and from smouldering-dominated behaviour near the end of combustion. During the flaming period, there was a strong correlation between the emission of black carbon and the rate of mass loss, which suggests there is value in employing a mass-based emission factor for this species. However, very little correlation was seen between organic aerosol and mass loss throughout the tests. As such, results here suggest that emission factors averaged over an entire combustion event are unlikely to be

  12. Measured and predicted aerosol light scattering enhancement factors at the high alpine site Jungfraujoch

    Directory of Open Access Journals (Sweden)

    R. Fierz-Schmidhauser

    2010-03-01

    Full Text Available Ambient relative humidity (RH determines the water content of atmospheric aerosol particles and thus has an important influence on the amount of visible light scattered by particles. The RH dependence of the particle light scattering coefficient (σsp is therefore an important variable for climate forcing calculations. We used a humidification system for a nephelometer which allows for the measurement of σsp at a defined RH in the range of 20–95%. In this paper we present measurements of light scattering enhancement factors f(RH=σsp(RH/σsp(dry from a 1-month campaign (May 2008 at the high alpine site Jungfraujoch (3580 m a.s.l., Switzerland. Measurements at the Jungfraujoch are representative for the lower free troposphere above Central Europe. For this aerosol type hardly any information about the f(RH is available so far. At this site, f(RH=85% varied between 1.2 and 3.3. Measured f(RH agreed well with f(RH calculated with Mie theory using measurements of the size distribution, chemical composition and hygroscopic diameter growth factors as input. Good f(RH predictions at RH<85% were also obtained with a simplified model, which uses the Ångström exponent of σsp(dry as input. RH influences further intensive optical aerosol properties. The backscatter fraction decreased by about 30% from 0.128 to 0.089, and the single scattering albedo increased on average by 0.05 at 85% RH compared to dry conditions. These changes in σsp, backscatter fraction and single scattering albedo have a distinct impact on the radiative forcing of the Jungfraujoch aerosol.

  13. CHASER: An Innovative Satellite Mission Concept to Measure the Effects of Aerosols on Clouds and Climate

    Science.gov (United States)

    Renno, N.; Williams, E.; Rosenfeld, D.; Fischer, D.; Fischer, J.; Kremic, T.; Agrawal, A.; Andreae, M.; Bierbaum, R.; Blakeslee, R.; Boerner, A.; Bowles, N.; Christian, H.; Dunion, J.; Horvath, A.; Huang, X.; Khain, A.; Kinne, S.; Lemos, M.-C.; Penner, J.

    2012-04-01

    The formation of cloud droplets on aerosol particles, technically known as the activation of cloud condensation nuclei (CCN), is the fundamental process driving the interactions of aerosols with clouds and precipitation. Knowledge of these interactions is foundational to our understanding of weather and climate. The Intergovernmental Panel on Climate Change (IPCC) and the Decadal Survey (NRC 2007) indicate that the uncertainty in how clouds adjust to aerosol perturbations dominates the uncertainty in the overall quantification of the radiative forcing attributable to human activities. The Clouds, Hazards, and Aerosols Survey for Earth Researchers (CHASER) mission concept responds to the IPCC and Decadal Survey concerns by studying the activation of CCN and their interactions with clouds and storms. CHASER proposes to revolutionize our understanding of the interactions of aerosols with clouds by making the first global measurements of the fundamental physical entity linking them: activated cloud condensation nuclei. The CHASER mission was conceptualized to measure all quantities necessary for determining the interactions of aerosols with clouds and storms. Measurements by current satellites allow the determination of crude profiles of cloud particle size but not of the activated CCN that seed them. CHASER uses a new technique (Freud et al. 2011; Rosenfeld et al. 2012) and high-heritage instruments to produce the first global maps of activated CCN and the properties of the clouds associated with them. CHASER measures the CCN concentration and cloud thermodynamic forcing simultaneously, allowing their effects to be distinguished. Changes in the behavior of a group of weather systems in which only one of the quantities varies (a partial derivative of the intensity with the desirable quantity) allow the determination of each effect statistically. The high uncertainties of current climate predictions limit their much-needed use in decision-making. CHASER mitigates this

  14. Remote Measurement of Pollution-A 40-Year Langley Retrospective. Part 2; Aerosols and Clouds

    Science.gov (United States)

    Remsberg, Ellis E.

    2012-01-01

    A workshop was convened in 1971 by the National Aeronautics and Space Administration (NASA) on the Remote Measurement of Pollution (RMOP), and the findings and recommendations of its participants are in a NASA Special Publication (NASA SP-285). The three primary workshop panels and their chairmen were focused on trace gas species (Will Kellogg), atmospheric particulates or aerosols (Verner Suomi), and water pollution (Gifford Ewing). Many of the workshop participants were specialists in the techniques that might be employed for regional to global-scale, remote measurements of the atmospheric parameters from Earth-orbiting satellites. In 2011 the author published a 40-year retrospective (or Part I) of the instrumental developments that were an outgrowth of the RMOP panel headed by Will Kellogg, i.e., on atmospheric temperature and gaseous species. The current report (or Part II) is an analogous retrospective of the vision of the panel led by Verner Suomi for the measurement of particulates (or aerosols) and clouds and for their effects on Earth s radiation budget. The class of measurement techniques includes laser radar or lidar, solar occultation, limb emission and scattering, nadir-viewing photometry or radiometry, and aerosol polarimetry. In addition, the retrospective refers to the scientific imperatives that led to those instrument developments of 1971-2010. Contributions of the atmospheric technologists at the Langley Research Center are emphasized, and their progress is placed in the context of the parallel and complementary work from within the larger atmospheric science community.

  15. Relationships between Personal Measurements of 'Total' Dust, Respirable, Thoracic, and Inhalable Aerosol Fractions in the Cement Production Industry.

    Science.gov (United States)

    Notø, Hilde P; Nordby, Karl-Christian; Eduard, Wijnand

    2016-05-01

    The aims of this study were to examine the relationships and establish conversion factors between 'total' dust, respirable, thoracic, and inhalable aerosol fractions measured by parallel personal sampling on workers from the production departments of cement plants. 'Total' dust in this study refers to aerosol sampled by the closed face 37-mm Millipore filter cassette. Side-by-side personal measurements of 'total' dust and respirable, thoracic, and inhalable aerosol fractions were performed on workers in 17 European and Turkish cement plants. Simple linear and mixed model regressions were used to model the associations between the samplers. The total number of personal samples collected on 141 workers was 512. Of these 8.4% were excluded leaving 469 for statistical analysis. The different aerosol fractions contained from 90 to 130 measurements and-side-by side measurements of all four aerosol fractions were collected on 72 workers.The median ratios between observed results of the respirable, 'total' dust, and inhalable fractions relative to the thoracic aerosol fractions were 0.51, 2.4, and 5.9 respectively. The ratios between the samplers were not constant over the measured concentration range and were best described by regression models. Job type, position of samplers on left or right shoulder and plant had no substantial effect on the ratios. The ratios between aerosol fractions changed with different air concentrations. Conversion models for estimation of the fractions were established. These models explained a high proportion of the variance (74-91%) indicating that they are useful for the estimation of concentrations based on measurements of a different aerosol fraction. The calculated uncertainties at most observed concentrations were below 30% which is acceptable for comparison with limit values (EN 482, 2012). The cement industry will therefore be able to predict the health related aerosol fractions from their former or future measurements of one of the

  16. Long-term measurements of aerosol optical parameters in Athens, Greece

    Science.gov (United States)

    Paraskevopoulou, Despoina; Liakakou, Eleni; Gerasopoulos, Evangelos; Mihalopoulos, Nikolaos

    2015-04-01

    Aerosol chemical composition was studied in conjunction with its optical properties in the area of Athens Greece. For this purpose, sampling of fine aerosol fraction (PM2,5) took place on a daily basis from August 2010 to April 2013 at an urban background location. The samples are subsequently analyzed for their content in organic (OC) and elemental carbon (EC), major ions and trace metals, resulting in the exercise of chemical mass closure. In parallel, the optical properties of aerosols are recorded using a nephelometer and a particle soot absorption photometer (PSAP), leading to the calculation of scattering (σscat) and absorption (σabs) coefficients, respectively; while single scattering albedo (SSA) and mass scattering and absorption efficiencies are thereinafter calculated. Daily σscat values provide an average of 30.1±3.9 Μm-1 while, the average of σabs is 5.2±1.4 Μm-1. The seasonal cycle of σscat presents maximum during summer and in November, due to long-range transport of aerosol from continental Europe and dust transfer from Africa, respectively. The estimated mass absorption efficiency of EC is estimated to be 8.3±0.2 m2 g-1 for the whole studied period, while the corresponding estimated mass scattering efficiency of PM2.5 is 1.7±0.1 m2 g-1 and does not affected by the presence of dust. The average SSA equals to 0.87±0.11 for the three-year period. On a seasonal basis, SSA presents maximum values during summer that is consistent with the reduction of EC - the main absorbing specie. Finally, the reconstruction of scattering coefficients was performed taking into consideration the measured chemistry of fine aerosol.

  17. Long-term measurements of carbonaceous aerosols in the eastern Mediterranean: evidence of long-range transport of biomass burning

    OpenAIRE

    Sciare , J.; Oikonomou , K.; Favez , O.; Markaki , Z.; Liakakou , E.; Cachier , H.; Mihalopoulos , N.

    2008-01-01

    International audience; Long-term (5-yr) measurements of Black Carbon (BC) and Organic Carbon (OC) in bulk aerosols are presented here for the first time in the Mediterranean Basin (Crete Island). A multi-analytical approach (including thermal, optical, and thermo-optical techniques) was applied for these BC and OC measurements. Light absorbing dust aerosols have shown to poorly contribute (+17% on a yearly average) to light absorption coefficient (babs) measurements performed by an optical m...

  18. Long-term measurements of carbonaceous aerosols in the Eastern Mediterranean: evidence of long-range transport of biomass burning

    OpenAIRE

    Sciare, J.; Oikonomou, K.; Favez, O.; Liakakou, E.; Markaki, Z.; Cachier, H.; Mihalopoulos, N.

    2008-01-01

    Long-term (5-year) measurements of Elemental Carbon (EC) and Organic Carbon (OC) in bulk aerosols are presented here for the first time in the Mediterranean Basin (Crete Island). A multi-analytical approach (including thermal, optical, and thermo-optical techniques) was applied for these EC and OC measurements. Light absorbing dust aerosols were shown to poorly contribute (+12% on a yearly average) to light absorption coefficient (babs) measurements performed by an optical m...

  19. Onshore Wind Speed Modulates Microbial Aerosols along an Urban Waterfront

    Directory of Open Access Journals (Sweden)

    M. Elias Dueker

    2017-11-01

    Full Text Available Wind blowing over aquatic and terrestrial surfaces produces aerosols, which include microbial aerosols. We studied the effect of onshore wind speeds on aerosol concentrations as well as total and culturable microbial aerosols (bacterial and viral at an urban waterfront (New York, NY, United States of America. We used two distinct methods to characterize microbial aerosol responses to wind speed: A culture-based exposure-plate method measuring viable bacterial deposition near-shore (CFU accumulation rate; and a culture-independent aerosol sampler-based method measuring total bacterial and viral aerosols (cells m−3 air. While ambient coarse (>2 µm and fine (0.3–2 µm aerosol particle number concentrations (regulated indicators of air quality decreased with increasing onshore wind speeds, total and depositing culturable bacterial aerosols and total viral aerosols increased. Taxonomic identification of the 16S rDNA of bacterial aerosol isolates suggested both terrestrial and aquatic sources. Wind appears to increase microbial aerosol number concentrations in the near-shore environment by onshore transport at low wind speeds (<4 m s−1, and increased local production and transport of new microbial aerosols from adjacent water surfaces at higher wind speeds (>4 m s−1. This study demonstrates a wind-modulated microbial connection between water and air in the coastal urban environment, with implications for public health management and urban microbial ecology.

  20. Aerosol effects in radiation transfer

    International Nuclear Information System (INIS)

    Binenko, V.I.; Harshvardhan, H.

    1993-01-01

    The radiative properties and effects of aerosols are assessed for the following aerosol sources: relatively clean background aerosol, dust storms and dust outbreaks, anthropogenic pollution, and polluted cloud layers. Studies show it is the submicron aerosol fraction that plays a dominant radiative role in the atmosphere. The radiative effect of the aerosol depends not only on its loading but also on the underlying surface albedo and on solar zenith angle. It is only with highly reflecting surfaces such as Arctic ice that aerosols have a warming effect. Radiometric, microphysical, mineral composition, and refractive index measurements are presented for dust and in particular for the Saharan aerosol layer (SAL). Short-wave radiative heating of the atmosphere is caused by the SAL and is due mainly to absorption. However, the SAL does not contribute significantly to the long-wave thermal radiation budget. Field program studies of the radiative effects of aerosols are described. Anthropogenic aerosols deplete the incoming solar radiation. A case field study for a regional Ukrainian center is discussed. The urban aerosol causes a cooling of metropolitan centers, compared with outlying areas, during the day, which is followed by a warming trend at night. In another study, an increase in turbidity by a factor of 3 due to increased industrialization for Mexico City is noted, together with a drop in atmospheric transmission by 10% over a 50-year period. Numerous studies are cited that demonstrate that anthropogenic aerosols affect both the microphysical and radiative properties of clouds, which in turn affect regional climate. Particles acting as cloud nuclei are considered to have the greatest indirect effect on cloud absorptivity of short-wave radiation. Satellite observations show that low-level stratus clouds contaminated by ship exhaust at sea lead to an increase in cloud albedo

  1. Gaseous ion-composition measurements in the young exhaust plume of jet aircraft at cruising altitudes. Implications for aerosols and gaseous sulfuric acid

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, F.; Wohlfrom, K.H.; Klemm, M.; Schneider, J.; Gollinger, K. [Max-Planck-Inst. for Nuclear Physics, Heidelberg (Germany); Schumann, U.; Busen, R. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere

    1997-12-31

    Mass spectrometric measurements were made in the young exhaust plume of an Airbus (A310) at cruising altitudes at distances between 400 and 800 m behind the Airbus (averaged plume age: 3.4 sec). The measurements indicate that gaseous sulfuric acid (GSA) number densities were less than 1.3 x 10{sup 8} cm{sup -3} which is smaller than the expected total sulfuric acid. Hence the missing sulfuric acid must have been in the aerosol phase. These measurements also indicate a total aerosol surface area density A{sub T} {<=} 5.4 x 10{sup -5} cm{sup 2} per cm{sup 3} which is consistent with simultaneously measured soot and water contrail particles. However, homogeneous nucleation leading to (H{sub 2}SO{sub 4}){sub x}(H{sub 2}O){sub y}-clusters can not be ruled out. (author) 16 refs.

  2. Gaseous ion-composition measurements in the young exhaust plume of jet aircraft at cruising altitudes. Implications for aerosols and gaseous sulfuric acid

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, F; Wohlfrom, K H; Klemm, M; Schneider, J; Gollinger, K [Max-Planck-Inst. for Nuclear Physics, Heidelberg (Germany); Schumann, U; Busen, R [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere

    1998-12-31

    Mass spectrometric measurements were made in the young exhaust plume of an Airbus (A310) at cruising altitudes at distances between 400 and 800 m behind the Airbus (averaged plume age: 3.4 sec). The measurements indicate that gaseous sulfuric acid (GSA) number densities were less than 1.3 x 10{sup 8} cm{sup -3} which is smaller than the expected total sulfuric acid. Hence the missing sulfuric acid must have been in the aerosol phase. These measurements also indicate a total aerosol surface area density A{sub T} {<=} 5.4 x 10{sup -5} cm{sup 2} per cm{sup 3} which is consistent with simultaneously measured soot and water contrail particles. However, homogeneous nucleation leading to (H{sub 2}SO{sub 4}){sub x}(H{sub 2}O){sub y}-clusters can not be ruled out. (author) 16 refs.

  3. Stratospheric aerosols

    International Nuclear Information System (INIS)

    Rosen, J.; Ivanov, V.A.

    1993-01-01

    Stratospheric aerosol measurements can provide both spatial and temporal data of sufficient resolution to be of use in climate models. Relatively recent results from a wide range of instrument techniques for measuring stratospheric aerosol parameters are described. Such techniques include impactor sampling, lidar system sensing, filter sampling, photoelectric particle counting, satellite extinction-sensing using the sun as a source, and optical depth probing, at sites mainly removed from tropospheric aerosol sources. Some of these techniques have also had correlative and intercomparison studies. The main methods for determining the vertical profiles of stratospheric aerosols are outlined: lidar extinction measurements from satellites; impactor measurements from balloons and aircraft; and photoelectric particle counter measurements from balloons, aircraft, and rockets. The conversion of the lidar backscatter to stratospheric aerosol mass loading is referred to. Absolute measurements of total solar extinction from satellite orbits can be used to extract the aerosol extinction, and several examples of vertical profiles of extinction obtained with the SAGE satellite are given. Stratospheric mass loading can be inferred from extinction using approximate linear relationships but under restrictive conditions. Impactor sampling is essentially the only method in which the physical nature of the stratospheric aerosol is observed visually. Vertical profiles of stratospheric aerosol number concentration using impactor data are presented. Typical profiles using a dual-size-range photoelectric dustsonde particle counter are given for volcanically disturbed and inactive periods. Some measurements of the global distribution of stratospheric aerosols are also presented. Volatility measurements are described, indicating that stratospheric aerosols are composed primarily of about 75% sulfuric acid and 25% water

  4. Visibility and aerosol measurement by diode-laser random-modulation CW lidar

    Science.gov (United States)

    Takeuchi, N.; Baba, H.; Sakurai, K.; Ueno, T.; Ishikawa, N.

    1986-01-01

    Examples of diode laser (DL) random-modulation continuous wave (RM-CW) lidar measurements are reported. The ability of the measurement of the visibility, vertical aerosol profile, and the cloud ceiling height is demonstrated. Although the data shown here were all measured at night time, the daytime measurement is, of course, possible. For that purpose, accurate control of the laser frequency to the center frequency of a narrow band filter is required. Now a new system with a frequency control is under construction.

  5. Estimation of the volatility distribution of organic aerosol combining thermodenuder and isothermal dilution measurements

    Science.gov (United States)

    Louvaris, Evangelos E.; Karnezi, Eleni; Kostenidou, Evangelia; Kaltsonoudis, Christos; Pandis, Spyros N.

    2017-10-01

    A method is developed following the work of Grieshop et al. (2009) for the determination of the organic aerosol (OA) volatility distribution combining thermodenuder (TD) and isothermal dilution measurements. The approach was tested in experiments that were conducted in a smog chamber using organic aerosol (OA) produced during meat charbroiling. A TD was operated at temperatures ranging from 25 to 250 °C with a 14 s centerline residence time coupled to a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a scanning mobility particle sizer (SMPS). In parallel, a dilution chamber filled with clean air was used to dilute isothermally the aerosol of the larger chamber by approximately a factor of 10. The OA mass fraction remaining was measured as a function of temperature in the TD and as a function of time in the isothermal dilution chamber. These two sets of measurements were used together to estimate the volatility distribution of the OA and its effective vaporization enthalpy and accommodation coefficient. In the isothermal dilution experiments approximately 20 % of the OA evaporated within 15 min. Almost all the OA evaporated in the TD at approximately 200 °C. The resulting volatility distributions suggested that around 60-75 % of the cooking OA (COA) at concentrations around 500 µg m-3 consisted of low-volatility organic compounds (LVOCs), 20-30 % of semivolatile organic compounds (SVOCs), and around 10 % of intermediate-volatility organic compounds (IVOCs). The estimated effective vaporization enthalpy of COA was 100 ± 20 kJ mol-1 and the effective accommodation coefficient was 0.06-0.07. Addition of the dilution measurements to the TD data results in a lower uncertainty of the estimated vaporization enthalpy as well as the SVOC content of the OA.

  6. Estimation of the volatility distribution of organic aerosol combining thermodenuder and isothermal dilution measurements

    Directory of Open Access Journals (Sweden)

    E. E. Louvaris

    2017-10-01

    Full Text Available A method is developed following the work of Grieshop et al. (2009 for the determination of the organic aerosol (OA volatility distribution combining thermodenuder (TD and isothermal dilution measurements. The approach was tested in experiments that were conducted in a smog chamber using organic aerosol (OA produced during meat charbroiling. A TD was operated at temperatures ranging from 25 to 250 °C with a 14 s centerline residence time coupled to a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS and a scanning mobility particle sizer (SMPS. In parallel, a dilution chamber filled with clean air was used to dilute isothermally the aerosol of the larger chamber by approximately a factor of 10. The OA mass fraction remaining was measured as a function of temperature in the TD and as a function of time in the isothermal dilution chamber. These two sets of measurements were used together to estimate the volatility distribution of the OA and its effective vaporization enthalpy and accommodation coefficient. In the isothermal dilution experiments approximately 20 % of the OA evaporated within 15 min. Almost all the OA evaporated in the TD at approximately 200 °C. The resulting volatility distributions suggested that around 60–75 % of the cooking OA (COA at concentrations around 500 µg m−3 consisted of low-volatility organic compounds (LVOCs, 20–30 % of semivolatile organic compounds (SVOCs, and around 10 % of intermediate-volatility organic compounds (IVOCs. The estimated effective vaporization enthalpy of COA was 100 ± 20 kJ mol−1 and the effective accommodation coefficient was 0.06–0.07. Addition of the dilution measurements to the TD data results in a lower uncertainty of the estimated vaporization enthalpy as well as the SVOC content of the OA.

  7. Contribution to the study of aerosol photometers, application to the measurement of filter efficiency

    International Nuclear Information System (INIS)

    Billard, F.; Hadelaine, G.

    1968-01-01

    The measurement of the quantity of diffused light by particulates in suspension in a gas allows to determine the concentration and the size of an aerosol. The aim of this work is to check the answer of the usual photometer in the laboratories, the Phoenix-Sinclair and the Royco-230. The minimum diameter of the particulates detected by these photometers is about 0.3 microns [fr

  8. Tropical intercontinental optical measurement network of aerosol, precipitable water and total column ozone

    Science.gov (United States)

    Holben, B. N.; Tanre, D.; Reagan, J. A.; Eck, T. F.; Setzer, A.; Kaufman, Y. A.; Vermote, E.; Vassiliou, G. D.; Lavenu, F.

    1992-01-01

    A new generation of automatic sunphotometers is used to systematically monitor clear sky total column aerosol concentration and optical properties, precipitable water and total column ozone diurnally and annually in West Africa and South America. The instruments are designed to measure direct beam sun, solar aureole and sky radiances in nine narrow spectral bands from the UV to the near infrared on an hourly basis. The instrumentation and the algorithms required to reduce the data for subsequent analysis are described.

  9. Combined ground-based and satellite remote sensing of atmospheric aerosol and Earth surface in the Antarctic

    Science.gov (United States)

    Chaikovsky, Anatoli; Korol, Michail; Malinka, A.; Zege, E.; Katsev, I.; Prikhach, A.; Denisov, S.; Dick, V.; Goloub, P.; Blarel, L.; Chaikovskaya, L.; Lapyonok, A.; Podvin, T.; Denishchik-Nelubina, N.; Fedarenka, A.; Svidinsky, V.

    2016-01-01

    The paper presents lecture materials given at the Nineteenth International Conference and School on Quantum Electronics "Laser Physics and Applications" (19th ICSQE) in 2016, Sozopol, Bulgaria and contains the results of the 10-year research of Belarusian Antarctic expeditions to study the atmospheric aerosol and Earth surface in Antarctica. The works focus on the studying variability and trends of aerosol, cloud and snow characteristics in the Antarctic and the links of these processes with the long range transport of atmospheric pollutants and climate changes.

  10. Atmospheric aerosol measurements by employing a polarization scheimpflug lidar system

    Science.gov (United States)

    Mei, Liang; Guan, Peng; Yang, Yang

    2018-04-01

    A polarization Scheimpflug lidar system based on the Scheimpflug principle has been developed by employing a compact 808-nm multimode highpower laser diode and two highly integrated CMOS sensors in Dalian University of Technology (DLUT), Dalian, China. The parallel and orthogonal polarized backscattering signal are recorded by two 45 degree tilted image sensors, respectively. Atmospheric particle measurements were carried out by employing the polarization Scheimpflug lidar system.

  11. Aerosol-foam interaction experiments

    International Nuclear Information System (INIS)

    Ball, M.H.E.; Luscombe, C.DeM.; Mitchell, J.P.

    1990-03-01

    Foam treatment offers the potential to clean gas streams containing radioactive particles. A large decontamination factor has been claimed for the removal of airborne plutonium dust when spraying a commercially available foam on the walls and horizontal surfaces of an alpha-active room. Experiments have been designed and undertaken to reproduce these conditions with a non-radioactive simulant aerosol. Careful measurements of aerosol concentrations with and without foam treatment failed to provide convincing evidence to support the earlier observation. The foam may not have been as well mixed with the aerosol in the present studies. Further work is required to explore more efficient mixing methods, including systems in which the aerosol steam is passed through the foam, rather than merely spraying foam into the path of the aerosol. (author)

  12. Kinetic model framework for aerosol and cloud surface chemistry and gas-particle interactions - Part 1: General equations, parameters, and terminology

    Science.gov (United States)

    Pöschl, U.; Rudich, Y.; Ammann, M.

    2007-12-01

    Aerosols and clouds play central roles in atmospheric chemistry and physics, climate, air pollution, and public health. The mechanistic understanding and predictability of aerosol and cloud properties, interactions, transformations, and effects are, however, still very limited. This is due not only to the limited availability of measurement data, but also to the limited applicability and compatibility of model formalisms used for the analysis, interpretation, and description of heterogeneous and multiphase processes. To support the investigation and elucidation of atmospheric aerosol and cloud surface chemistry and gas-particle interactions, we present a comprehensive kinetic model framework with consistent and unambiguous terminology and universally applicable rate equations and parameters. It enables a detailed description of mass transport and chemical reactions at the gas-particle interface, and it allows linking aerosol and cloud surface processes with gas phase and particle bulk processes in systems with multiple chemical components and competing physicochemical processes. The key elements and essential aspects of the presented framework are: a simple and descriptive double-layer surface model (sorption layer and quasi-static layer); straightforward flux-based mass balance and rate equations; clear separation of mass transport and chemical reactions; well-defined and consistent rate parameters (uptake and accommodation coefficients, reaction and transport rate coefficients); clear distinction between gas phase, gas-surface, and surface-bulk transport (gas phase diffusion, surface and bulk accommodation); clear distinction between gas-surface, surface layer, and surface-bulk reactions (Langmuir-Hinshelwood and Eley-Rideal mechanisms); mechanistic description of concentration and time dependences (transient and steady-state conditions); flexible addition of unlimited numbers of chemical species and physicochemical processes; optional aggregation or resolution

  13. The unique properties of agricultural aerosols measured at a cattle feeding operation

    Science.gov (United States)

    Hiranuma, N.; Brooks, S. D.; Gramann, J.; Auvermann, B. W.

    2011-05-01

    Housing roughly 10 million head of cattle in the United States alone, open air cattle feedlots represent a significant but poorly constrained source of atmospheric particles. Here we present a comprehensive characterization of physical and chemical properties of particles emitted from a large representative cattle feedlot in the Southwest United States. In the summer of 2008, measurements and samplings were conducted at the nominally upwind and downwind edges of the facility. A series of far-field measurements and samplings was also conducted 3.5 km north of the facility. Two instruments, a GRIMM Sequential Mobility Particle Sizer (SMPS) and a GRIMM Portable Aerosol Spectrometer (PAS), were used to measure particle size distributions over the range of 0.01 to 25 μm diameter. Raman microspectroscopy (RM) was used to determine the chemical composition of particles on a single particle basis. Volume size distributions of fugitive dust were dominated by coarse mode particles. Twenty-four hour averaged concentrations of PM10 (particulate matter with a diameter of 10 μm or less) were as high as 1200 μg m-3 during the campaign. The primary constituents of the particulate matter were carbonaceous materials, such as humic acid, water soluble organics, and less soluble fatty acids, including stearic acid and tristearin. A significant percentage of the organic particles, up to 28 %, were composed of internally mixed with salts. Basic characteristics such as size distribution and composition of agricultural aerosols were found to be different than the properties of those found in urban and semi-urban aerosols. Failing to account for such differences will lead to serious errors in estimates of aerosol effects on climate, visibility, and public health.

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

    Science.gov (United States)

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

    2002-01-01

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

  15. Aerosol optical properties and radiative forcing in the high Himalaya based on measurements at the Nepal Climate Observatory-Pyramid site (5079 m a.s.l.

    Directory of Open Access Journals (Sweden)

    S. Marcq

    2010-07-01

    Full Text Available Intense anthropogenic emissions over the Indian sub-continent lead to the formation of layers of particulate pollution that can be transported to the high altitude regions of the Himalaya-Hindu-Kush (HKH. Aerosol particles contain a substantial fraction of strongly absorbing material, including black carbon (BC, organic compounds (OC, and dust all of which can contribute to atmospheric warming, in addition to greenhouse gases. Using a 3-year record of continuous measurements of aerosol optical properties, we present a time series of key climate relevant aerosol properties including the aerosol absorption (σap and scattering (σsp coefficients as well as the single-scattering albedo (w0. Results of this investigation show substantial seasonal variability of these properties, with long range transport during the pre- and post-monsoon seasons and efficient precipitation scavenging of aerosol particles during the monsoon season. The monthly averaged scattering coefficients range from 0.1 Mm−1 (monsoon to 20 Mm−1 while the average absorption coefficients range from 0.5 Mm−1 to 3.5 Mm−1. Both have their maximum values during the pre-monsoon period (April and reach a minimum during Monsoon (July–August. This leads to dry w0 values from 0.86 (pre-monsoon to 0.79 (monsoon seasons. Significant diurnal variability due to valley wind circulation is also reported. Using aerosol optical depth (AOD measurements, we calculated the resulting direct local radiative forcing due to aerosols for selected air mass cases. We found that the presence of absorbing particulate material can locally induce an additional top of the atmosphere (TOA forcing of 10 to 20 W m−2 for the first atmospheric layer (500 m above surface. The TOA positive forcing depends on the presence of snow at the surface, and takes place preferentially during episodes of

  16. Cavity Attenuated Phase Shift (CAPS) Method for Airborne Aerosol Light Extinction Measurement: Instrument Validation and First Results from Field Deployment

    Science.gov (United States)

    Petzold, A.; Perim de Faria, J.; Berg, M.; Bundke, U.; Freedman, A.

    2015-12-01

    Monitoring the direct impact of aerosol particles on climate requires the continuous measurement of aerosol optical parameters like the aerosol extinction coefficient on a regular basis. Remote sensing and ground-based networks are well in place (e.g., AERONET, ACTRIS), whereas the regular in situ measurement of vertical profiles of atmospheric aerosol optical properties remains still an important challenge in quantifying climate change. The European Research Infrastructure IAGOS (In-service Aircraft for a Global Observing System; www.iagos.org) responds to the increasing requests for long-term, routine in situ observational data by using commercial passenger aircraft as measurement platform. However, scientific instrumentation for the measurement of atmospheric constituents requires major modifications before being deployable aboard in-service passenger aircraft. Recently, a compact and robust family of optical instruments based on the cavity attenuated phase shift (CAPS) technique has become available for measuring aerosol light extinction. While this technique was successfully deployed for ground-based atmospheric measurements under various conditions, its suitability for operation aboard aircraft in the free and upper free troposphere still has to be demonstrated. In this work, the modifications of a CAPS PMex instrument for measuring aerosol light extinction on aircraft, the results from subsequent laboratory tests for evaluating the modified instrument prototype, and first results from a field deployment aboard a research aircraft will be covered. In laboratory studies, the instrument showed excellent agreement (deviation CAPS PMex instrument response within 10% deviation. During the field deployment, aerosol extinction coefficients and associated aerosol size distributions have been measured and will be presented as comparison studies between measured and calculated data.

  17. Exploring the relationship between monitored ground-based and satellite aerosol measurements over the City of Johannesburg

    CSIR Research Space (South Africa)

    Garland, Rebecca M

    2012-09-01

    Full Text Available This project studied the relationship between aerosol optical depth (AOD) from the Multi-angle Imaging SpectroRadiometer (MISR) instrument on the Terra satellite, and ground-based monitored particulate matter (PM) mass concentrations measured...

  18. Measurement of ambient aerosol hydration state at Great Smoky Mountains National Park in the southeastern United States

    Directory of Open Access Journals (Sweden)

    N. F. Taylor

    2011-12-01

    Full Text Available We present results from two field deployments of a unique tandem differential mobility analyzer (TDMA configuration with two primary capabilities: identifying alternative stable or meta-stable ambient aerosol hydration states associated with hysteresis in aerosol hydration behavior and determining the actual Ambient hydration State (AS-TDMA. This data set is the first to fully classify the ambient hydration state of aerosols despite recognition that hydration state significantly impacts the roles of aerosols in climate, visibility and heterogeneous chemistry. The AS-TDMA was installed at a site in eastern Tennessee on the border of Great Smoky Mountains National Park for projects during the summer of 2006 and winter of 2007–2008. During the summer, 12% of the aerosols sampled in continuous AS-TDMA measurements were found to posses two possible hydration states under ambient conditions. In every case, the more hydrated of the possible states was occupied. The remaining 88% did not posses multiple possible states. In continuous measurements during the winter, 49% of the aerosols sampled possessed two possible ambient hydration states; the remainder possessed only one. Of those aerosols with multiple possible ambient hydration states, 65% occupied the more hydrated state; 35% occupied the less hydrated state. This seasonal contrast is supported by differences in the fine particulate (PM2.5 composition and ambient RH as measured during the two study periods. In addition to seasonal summaries, this work includes case studies depicting the variation of hydration state with changing atmospheric conditions.

  19. Submicron aerosol distributions and CCN activity measured in and around the Korean Peninsula during KORUS-AQ

    Science.gov (United States)

    Park, M.; Kim, N.; Yum, S. S.; Thornhill, K. L., II; Anderson, B. E.; Kim, D. S.; Kim, H. J.; Jeon, H. E.; Park, Y. S.; Lee, S. B.

    2017-12-01

    KORUS-AQ is a field campaign aimed at investigating formation of ozone and aerosol and interactions between chemistry, transport and various sources in the Korean Peninsula which is the region affected both by long-range transport and local emission. Aerosol number concentration and size distribution, and CCN number concentration were measured on board the NASA DC-8 research aircraft and at a ground site at Olympic Park in Seoul, capital city of Korea during the KORUS-AQ campaign (May 2nd to June 10th, 2017). There were 20 flights during the KORUS-AQ campaign and total flight time was about 150 hours. CCN counter (CCNC) on the airborne platform was operated at the fixed internal supersaturation of 0.6% and CCNC at the ground site was operated at five different supersaturations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%). Aerosol hygroscopic parameter κ was also estimated from CCN number concentration and aerosol size distribution. Airborne measurements showed a large spatio-temporal variation of aerosol number concentration and CCN activity in and around the Korean peninsula, and the ground measurements also showed a large temporal variation. The campaign period can be classified into long-range transport dominant cases, local emission dominant cases due to stagnant air mass, and others. Aerosol number concentration in the Korean Peninsula measured in stagnant air mass period was higher than those in long-range transport