Science.gov

Sample records for aerosol extinction ozone

  1. Antarctic measurements of ozone, water vapor, and aerosol extinction by Sage 2 in the spring of 1987

    NASA Technical Reports Server (NTRS)

    Larsen, J. C.; Mccormick, M. Patrick

    1988-01-01

    Recent measurements of ozone, water vapor, and aerosol extinction from the spring of 1987 are presented and compared to 1985 and 1986. The observed changes to variations in meteorological conditions in the vortex for these three years are noted. March ozone data at similar latitudes for these three years will be used to investigate coupling between severity of the springtime depletion and early fall values. Researchers also investigate correlations between the measured species of water vapor, ozone, and aerosols throughout the vortex region.

  2. Antarctic springtime measurements of ozone, nitrogen dioxide, and aerosol extinction by SAM II, SAGE, and SAGE II

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Larsen, J. C.

    1986-01-01

    Simultaneous vertical profiles of O3, NO2, and aerosol extinction obtained with the Stratospheric Aerosol Measurement II, Stratospheric Aerosol and Gas Experiment (SAGE), and SAGE II satellite instruments across the southern polar vortex show that significant differences exist at all altitudes. Both gaseous species display lower concentrations within the vortex over measurement altitudes ranging from the tropopause to 60 km and 20 to 40 km for O3 and NO2, respectively. Aerosol extinction above 15-18 km and total aerosol stratospheric column are also lower inside the vortex than outside. Total column amounts of O3 and NO2 are found to be strongly coupled to spatial location within the vortex, with minimum total values located around the vortex center. Vertical profiles selected to emphasize the observed difference across the circumpolar vortex are presented for October 13, 1981, and October 13, 1985, near 70 and 68 deg S latitude, respectively.

  3. Aerosol extinction measurements with CO2-lidar

    NASA Technical Reports Server (NTRS)

    Hagard, Arne; Persson, Rolf

    1992-01-01

    With the aim to develop a model for infrared extinction due to aerosols in slant paths in the lower atmosphere we perform measurements with a CO2-lidar. Earlier measurements with a transmissometer along horizontal paths have been used to develop relations between aerosol extinction and meteorological parameters. With the lidar measurements we hope to develop corresponding relations for altitude profiles of the aerosol extinction in the infrared. An important application is prediction of detection range for infrared imaging systems.

  4. Aerosol Correction for Improving OMPS/LP Ozone Retrieval

    NASA Technical Reports Server (NTRS)

    Chen, Zhong; Bhartia, Pawan K.; Loughman, Robert

    2015-01-01

    The Ozone Mapping and Profiler Suite Limb Profiler (OMPS-LP) on board the Suomi National Polar-orbiting Partnership (SNPP) satellite was launched on Oct. 28, 2011. Limb profilers measures the radiance scattered from the Earth's atmospheric in limb viewing mode from 290 to 1000 nm and infer ozone profiles from tropopause to 60 km. The recently released OMPS-LP Version 2 data product contains the first publicly released ozone profiles retrievals, and these are now available for the entire OMPS mission, which extends from April, 2012. The Version 2 data product retrievals incorporate several important improvements to the algorithm. One of the primary changes is to turn off the aerosol retrieval module. The aerosol profiles retrieved inside the ozone code was not helping the ozone retrieval and was adding noise and other artifacts. Aerosols including polar stratospheric cloud (PSC) and polar mesospheric clouds (PMC) have a detectable effect on OMPS-LP data. Our results show that ignoring the aerosol contribution would produce an ozone density bias of up to 10 percent in the region of maximum aerosol extinction. Therefore, aerosol correction is needed to improve the quality of the retrieved ozone concentration profile. We provide Aerosol Scattering Index (ASI) for detecting aerosols-PMC-PSC, defined as ln(Im-Ic) normalized at 45km, where Im is the measured radiance and Ic is the calculated radiance assuming no aerosols. Since ASI varies with wavelengths, latitude and altitude, we can start by assuming no aerosol profiles in calculating the ASIs and then use the aerosol profile to see if it significantly reduces the residuals. We also discuss the effect of aerosol size distribution on the ozone profile retrieval process. Finally, we present an aerosol-PMC-PSC correction scheme.

  5. Wavelength dependence of aerosol extinction coefficient for stratospheric aerosols

    NASA Technical Reports Server (NTRS)

    Yue, Glenn K.

    1986-01-01

    A simple empirical formula for the wavelength dependence of the aerosol extinction coefficient is proposed. The relationship between the constants in the formula and the variable parameter in the aerosol size distribution is explicitly expressed. Good agreement is found between the extinction coefficients calculated from the proposed formula and that calculated from Mie theory. The proposed expression is shown to be better than the Angstroem formula commonly used by atmospheric scientists.

  6. In Situ Measurement of Aerosol Extinction

    NASA Technical Reports Server (NTRS)

    Strawa, Anthony W.; Castaneda, R.; Owano, T. G.; Bear, D.; Gore, Warren J. (Technical Monitor)

    2001-01-01

    Aerosols are important contributors to the radiative forcing in the atmosphere. Much of the uncertainty in our knowledge of climate forcing is due to uncertainties in the radiative forcing due to aerosols as illustrated in the IPCC reports of the last ten years. Improved measurement of aerosol optical properties, therefore, is critical to an improved understanding of atmospheric radiative forcing. Additionally, attempts to reconcile in situ and remote measurements of aerosol radiative properties have generally not been successful. This is due in part to the fact that it has been impossible to measure aerosol extinction in situ in the past. In this presentation we introduce a new instrument that employs the techniques used in cavity ringdown spectroscopy to measure the aerosol extinction and scattering coefficients in situ. A prototype instrument has been designed and tested in the lab and the field. It is capable of measuring aerosol extinction coefficient to 2x10(exp -6) per meter. This prototype instrument is described and results are presented.

  7. Humidity Dependent Extinction of Clay Aerosols

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  8. Retrieval of Aerosol Properties from Multi-Spectral Extinction Measurements

    NASA Technical Reports Server (NTRS)

    Lacis, Andrew A.

    1999-01-01

    The direct-beam spectral extinction of solar radiation contains information on atmospheric composition in a form that is essentially free from the data analysis complexities that often arise from multiple scattering. Ground based Multi-Filter Shadowband Radiometer (MFRSR) measurements provide such information for the vertical atmospheric column path, while solar occultation measurements from a satellite platform provide horizontal slices through the atmosphere. We describe application of a Multi-Spectral Atmospheric Column Extinction (MACE) analysis technique used to analyze MFRSR data also to occultation measurements made by SAGE II. For analysis, we select the 1985 Nevado del Ruiz volcanic eruption period to retrieve atmospheric profiles of ozone and NO2, and changes in the stratospheric aerosol size and optical depth. The time evolution of volcanic aerosol serves as a passive tracer to study stratospheric dynamics, and changes in particle size put constraints on the sulfur chemistry modeling of volcanic aerosols. Paper presented at The '99 Kyoto Aerosol-Cloud Workshop, held Dec 1-3, 1999, Kyoto, Japan

  9. Balloonborne ozone and aerosol measurements in the antarctic ozone hole

    SciTech Connect

    Hofmann, D.J.; Harder, J.W.; Rolf, S.R.; Rosen, J.M. )

    1987-01-01

    The National Ozone Expedition (NOZE) was mounted in 1986 using winter fly-in flights to McMurdo Station in August, which is approximately the time the ozone reduction begins. The University of Wyoming Atmospheric Physics group participated in this expedition through balloonborne measurements of the vertical distribution of ozone and aerosol particles. Between 24 August and 6 November, 33 ozone soundings, 6 aerosol sounding, and 3 condensation nuclei soundings were conducted using polyethylene balloons which were able to penetrate the cold (< {minus}80C) antarctic stratosphere. The authors summarize these results here.

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

    NASA Technical Reports Server (NTRS)

    2005-01-01

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

  11. Light extinction by secondary organic aerosol: an intercomparison of three broadband cavity spectrometers

    NASA Astrophysics Data System (ADS)

    Varma, R. M.; Ball, S. M.; Brauers, T.; Dorn, H.-P.; Heitmann, U.; Jones, R. L.; Platt, U.; Pöhler, D.; Ruth, A. A.; Shillings, A. J. L.; Thieser, J.; Wahner, A.; Venables, D. S.

    2013-11-01

    Broadband optical cavity spectrometers are maturing as a technology for trace-gas detection, but only recently have they been used to retrieve the extinction coefficient of aerosols. Sensitive broadband extinction measurements allow explicit separation of gas and particle phase spectral contributions, as well as continuous spectral measurements of aerosol extinction in favourable cases. In this work, we report an intercomparison study of the aerosol extinction coefficients measured by three such instruments: a broadband cavity ring-down spectrometer (BBCRDS), a cavity-enhanced differential optical absorption spectrometer (CE-DOAS), and an incoherent broadband cavity-enhanced absorption spectrometer (IBBCEAS). Experiments were carried out in the SAPHIR atmospheric simulation chamber as part of the NO3Comp campaign to compare the measurement capabilities of NO3 and N2O5 instrumentation. Aerosol extinction coefficients between 655 and 690 nm are reported for secondary organic aerosols (SOA) formed by the NO3 oxidation of β-pinene under dry and humid conditions. Despite different measurement approaches and spectral analysis procedures, the three instruments retrieved aerosol extinction coefficients that were in close agreement. The refractive index of SOA formed from the β-pinene + NO3 reaction was 1.61, and was not measurably affected by the chamber humidity or by aging of the aerosol over several hours. This refractive index is significantly larger than SOA refractive indices observed in other studies of OH and ozone-initiated terpene oxidations, and may be caused by the large proportion of organic nitrates in the particle phase. In an experiment involving ammonium sulfate particles, the aerosol extinction coefficients as measured by IBBCEAS were found to be in reasonable agreement with those calculated using the Mie theory. The results of the study demonstrate the potential of broadband cavity spectrometers for determining the optical properties of aerosols.

  12. Light extinction by Secondary Organic Aerosol: an intercomparison of three broadband cavity spectrometers

    NASA Astrophysics Data System (ADS)

    Varma, R. M.; Ball, S. M.; Brauers, T.; Dorn, H.-P.; Heitmann, U.; Jones, R. L.; Platt, U.; Pöhler, D.; Ruth, A. A.; Shillings, A. J. L.; Thieser, J.; Wahner, A.; Venables, D. S.

    2013-07-01

    Broadband optical cavity spectrometers are maturing as a technology for trace gas detection, but only recently have they been used to retrieve the extinction coefficient of aerosols. Sensitive broadband extinction measurements allow explicit separation of gas and particle phase spectral contributions, as well as continuous spectral measurements of aerosol extinction in favourable cases. In this work, we report an intercomparison study of the aerosol extinction coefficients measured by three such instruments: a broadband cavity ring-down spectrometer (BBCRDS), a cavity-enhanced differential optical absorption spectrometer (CE-DOAS), and an incoherent broadband cavity-enhanced absorption spectrometer (IBBCEAS). Experiments were carried out in the SAPHIR atmospheric simulation chamber as part of the NO3Comp campaign to compare the measurement capabilities of NO3 and N2O5 instrumentation. Aerosol extinction coefficients between 655 and 690 nm are reported for secondary organic aerosols (SOA) formed by the NO3 oxidation of β-pinene under dry and humid conditions. Despite different measurement approaches and spectral analysis procedures, the three instruments retrieved aerosol extinction coefficients that were in close agreement. The refractive index of SOA formed from the β-pinene + NO3 reaction was 1.61, and was not measurably affected by the chamber humidity or by aging of the aerosol over several hours. This refractive index is significantly larger than SOA refractive indices observed in other studies of OH and ozone-initiated terpene oxidations, and may be caused by the large proportion of organic nitrates in the particle phase. In an experiment involving ammonium sulphate particles the aerosol extinction coefficients as measured by IBBCEAS were found to be in reasonable agreement with those calculated using Mie theory. The results of the study demonstrate the potential of broadband cavity spectrometers for determining the optical properties of aerosols.

  13. Requirements For Lidar Aerosol and Ozone Measurements

    NASA Astrophysics Data System (ADS)

    Frey, S.; Woeste, L.

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

  14. Influence of the aerosol solar extinction on photochemistry during the 2010 Russian wildfires episode

    NASA Astrophysics Data System (ADS)

    Péré, J. C.; Bessagnet, B.; Pont, V.; Mallet, M.; Minvielle, F.

    2015-10-01

    In this work, impact of aerosol solar extinction on the photochemistry over eastern Europe during the 2010 wildfires episode is discussed for the period from 5 to 12 August 2010, which coincides to the peak of fire activity. The methodology is based on an online coupling between the chemistry-transport model CHIMERE (extended by an aerosol optical module) and the radiative transfer code TUV. Results of simulations indicate an important influence of the aerosol solar extinction, in terms of intensity and spatial extent, with a reduction of the photolysis rates of NO2 and O3 up to 50 % (in daytime average) along the aerosol plume transport. At a regional scale, these changes in photolysis rates lead to a 3-15 % increase in the NO2 daytime concentration and to an ozone reduction near the surface of 1-12 %. The ozone reduction is shown to occur over the entire boundary layer, where aerosols are located. Also, the total aerosol mass concentration (PM10) is shown to be decreased by 1-2 %, on average during the studied period, caused by a reduced formation of secondary aerosols such as sulfates and secondary organics (4-10 %) when aerosol impact on photolysis rates is included. In terms of model performance, comparisons of simulations with air quality measurements at Moscow indicate that an explicit representation of aerosols interaction with photolysis rates tend to improve the estimation of the near-surface concentration of ozone and nitrogen dioxide as well as the formation of inorganic aerosol species such as ammonium, nitrates and sulfates.

  15. Infrared Extinction Spectra of Mineral Dust Aerosol

    NASA Astrophysics Data System (ADS)

    Kleiber, P.; Laskina, O.; Alexander, J. M.; Young, M.; Grassian, V. H.

    2012-12-01

    Mineral dust aerosol affects the atmosphere by absorbing and scattering radiation and plays an important role in the Earth's radiative budget. The effect of atmospheric dust on climate is studied by various remote sensing techniques that use measurements from narrow band IR channels of satellites to determine key atmospheric properties. Therefore, it is essential to take radiative effects of mineral dust aerosol into account to correctly process remote sensing data. As aerosols are transported through the atmosphere they undergo aging and heterogeneous chemistry. This leads to changes in their optical properties and their effects on climate. In this study we carried out spectral simulations using both Mie theory and solutions derived in the Rayleigh regime for authentic dust samples and several processed components of mineral dust. Simulations of the extinction based on Mie theory shows that it does not accurately reproduce the peak position and band shape of the prominent IR resonance features. Errors in the simulated peak position and the line shape associated with Mie theory can adversely affect determination of mineral composition based on IR satellite data. Analytic solutions for various shapes derived from Rayleigh theory offer a better fit to the major band features of the spectra, therefore the accuracy of modeling atmospheric dust properties can be improved by using these analytic solutions. It is also important to take aging of mineral dust into account. We investigated the effect of chemical processing on the optical properties. It was shown that interactions of components of mineral dust (calcite, quartz and kaolinite) with humic and organic acids cause a shift of the IR resonance bands of these minerals. It may indicate changes in shape of the particles as well as changes in hygroscopicity and, as the result, the water content in these samples. Therefore, care should be taken when modeling optical properties of aged mineral dust.

  16. Scanning tropospheric ozone and aerosol lidar with double-gated photomultipliers.

    PubMed

    Machol, Janet L; Marchbanks, Richard D; Senff, Christoph J; McCarty, Brandi J; Eberhard, Wynn L; Brewer, William A; Richter, Ronald A; Alvarez, Raul J; Law, Daniel C; Weickmann, Ann M; Sandberg, Scott P

    2009-01-20

    The Ozone Profiling Atmospheric Lidar is a scanning four-wavelength ultraviolet differential absorption lidar that measures tropospheric ozone and aerosols. Derived profiles from the lidar data include ozone concentration, aerosol extinction, and calibrated aerosol backscatter. Aerosol calibrations assume a clear air region aloft. Other products include cloud base heights, aerosol layer heights, and scans of particulate plumes from aircraft. The aerosol data range from 280 m to 12 km with 5 m range resolution, while the ozone data ranges from 280 m to about 1.2 km with 100 m resolution. In horizontally homogeneous atmospheres, data from multiple-elevation angles is combined to reduce the minimum altitude of the aerosol and ozone profiles to about 20 m. The lidar design, the characterization of the photomultiplier tubes, ozone and aerosol analysis techniques, and sample data are described. Also discussed is a double-gating technique to shorten the gated turn-on time of the photomultiplier tubes, and thereby reduce the detection of background light and the outgoing laser pulse. PMID:19151820

  17. Lidar monitoring of atmospheric ozone and aerosol

    NASA Astrophysics Data System (ADS)

    Chudzynski, Stanislaw; Czyzewski, A.; Ernst, Krzysztof; Skubiszak, Wojciech; Stacewicz, Tadeusz; Stelmaszczyk, K.; Szymanski, Artur

    2000-11-01

    The growth of aerosol and ozone concentrations in the troposphere stimulates development of monitoring techniques allowing their detection. DIAL (Differential Absorption Lidar) is one of the most promising methods. It allows the remote measurements of selected pollutants within the range of few kilometers and with spatial resolution of few meters. We introduce the basic principles of the DIAL method and describe shortly our mobile lidar system. We present and comment selected registrations of ozone and aerosol concentration distributions obtained during summer field campaigns of 1997 and 1998.

  18. Inter-Comparison of ILAS-II Version 1.4 Aerosol Extinction Coefficient at 780 nm with SAGE II, SAGE III, and POAM III Aerosol Data

    NASA Technical Reports Server (NTRS)

    Saitoh, Naoko; Hayashida, S.; Sugita, T.; Nakajima, H.; Yokota, T.; Hayashi, M.; Shiraishi, K.; Kanzawa, H.; Ejiri, M. K.; Irie, H.; Tanaka, T.; Terao, Y.; Kobayashi, H.; Sasano, Y.; Bevilacqua, R.; Randall, C.; Thomason, L.; Taha, G.

    2006-01-01

    The Improved Limb Atmospheric Spectrometer (ILAS) II on board the Advanced Earth Observing Satellite (ADEOS) II observed stratospheric aerosol in visible/near-infrared/infrared spectra over high latitudes in the Northern and Southern Hemispheres. Observations were taken intermittently from January to March, and continuously from April through October, 2003. We assessed the data quality of ILAS-II version 1.4 aerosol extinction coefficients at 780 nm from comparisons with the Stratospheric Aerosol and Gas Experiment (SAGE) II, SAGE III, and the Polar Ozone and Aerosol Measurement (POAM) III aerosol data. At heights below 20 km in the Northern Hemisphere, aerosol extinction coefficients from ILAS-II agreed with those from SAGE II and SAGE III within 10%, and with those from POAM III within 15%. From 20 to 26 km, ILAS-II aerosol extinction coefficients were smaller than extinction coefficients from the other sensors; differences between ILAS-II and SAGE II ranged from 10% at 20 km to 34% at 26 km. ILAS-II aerosol extinction coefficients from 20 to 25 km in February over the Southern Hemisphere had a negative bias (12-66%) relative to SAGE II aerosol data. The bias increased with increasing altitude. Comparisons between ILAS-II and POAM III aerosol extinction coefficients from January to May in the Southern Hemisphere (defined as the non-Polar Stratospheric Cloud (PSC) season ) yielded qualitatively similar results. From June to October (defined as the PSC season ), aerosol extinction coefficients from ILAS-II were smaller than those from POAM III above 17 km, as in the case of the non-PSC season; however, ILAS-II and POAM III aerosol data were within 15% of each other from 12 to 17 km.

  19. Microphysical Modeling and POAM III Observations of Aerosol Extinction in the 1998-2003 Antarctic Stratosphere

    NASA Astrophysics Data System (ADS)

    Benson, C. M.; Drdla, K.; Nedoluha, G. E.; Shettle, E. P.; Alfred, J.; Hoppel, K. W.

    2005-12-01

    The Integrated Microphysics and Chemistry on Trajectories (IMPACT) model is used to study Polar stratospheric cloud formation and evolution in the Southern Polar vortex during the 1998-2003 winters. The model is applied to individual air parcels which are advected through the vortex on UKMO wind and temperature fields. The parcel temperature and pressure histories are used by IMPACT to calculate the formation and sedimentation of ice, NAT, SAT, and STS aerosols. Model results are validated by the Polar Ozone and Aerosol Measurement (POAM) III solar occultation instrument. Comparisons of POAM data to the model results help to constrain the microphysical parameters influencing aerosol formation and growth. Measurements of the water vapor mixing ratio are of limited use in clarifying the model microphysics; however, POAM measurements of aerosol extinction prove to be valuable in differentiating model runs. Specifically, the relationship of aerosol extinction to temperature arises from the different temperatures at which the various particle types form and grow. Comparisons of IMPACT calculations of this relationship to POAM measurements constrain the initial fraction of nuclei available for heterogeneous NAT freezing to 0.02% of all aerosols. Constraints are also placed on the ice accommodation coefficient and the NAT-ice lattice compatibility factor. However, these two parameters have similar effects on the extinction-temperature relationship, and thus a range of values are permissible for each.

  20. Measurements of Stratospheric Pinatubo Aerosol Extinction Profiles by a Raman Lidar

    NASA Technical Reports Server (NTRS)

    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. We 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 we 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. We 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.

  1. Mount St. Helens related aerosol properties from solar extinction measurements

    SciTech Connect

    Michalsky, J.J.; Kleckner, E.W.; Stokes, G.M.

    1980-11-01

    The optical extinction due to the introduction of aerosols and aerosol-precursors into the troposphere and stratosphere during the major eruptive phase of Mount St. Helens, Washington, is quantified. The concentration is on the two-week period centered on the major eruption of 22 July 1980. (ACR)

  2. Optical extinction of highly porous aerosol following atmospheric freeze drying

    NASA Astrophysics Data System (ADS)

    Adler, Gabriela; Haspel, Carynelisa; Moise, Tamar; Rudich, Yinon

    2014-06-01

    Porous glassy particles are a potentially significant but unexplored component of atmospheric aerosol that can form by aerosol processing through the ice phase of high convective clouds. The optical properties of porous glassy aerosols formed from a freeze-dry cycle simulating freezing and sublimation of ice particles were measured using a cavity ring down aerosol spectrometer (CRD-AS) at 532 nm and 355 nm wavelength. The measured extinction efficiency was significantly reduced for porous organic and mixed organic-ammonium sulfate particles as compared to the extinction efficiency of the homogeneous aerosol of the same composition prior to the freeze-drying process. A number of theoretical approaches for modeling the optical extinction of porous aerosols were explored. These include effective medium approximations, extended effective medium approximations, multilayer concentric sphere models, Rayleigh-Debye-Gans theory, and the discrete dipole approximation. Though such approaches are commonly used to describe porous particles in astrophysical and atmospheric contexts, in the current study, these approaches predicted an even lower extinction than the measured one. Rather, the best representation of the measured extinction was obtained with an effective refractive index retrieved from a fit to Mie scattering theory assuming spherical particles with a fixed void content. The single-scattering albedo of the porous glassy aerosols was derived using this effective refractive index and was found to be lower than that of the corresponding homogeneous aerosol, indicating stronger relative absorption at the wavelengths measured. The reduced extinction and increased absorption may be of significance in assessing direct, indirect, and semidirect forcing in regions where porous aerosols are expected to be prevalent.

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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

    Aerosols influence the Earth's radiative budget by scattering and absorbing incoming solar radiation. The optical properties of aerosols vary as a function of wavelength, but few measurements have reported the wavelength dependence of aerosol extinction cross-sections and complex refractive indices. We describe a new laboratory instrument to measure aerosol optical extinction as a function of wavelength, using cavity enhanced spectroscopy with a broadband light source. The instrument consists of two broadband channels which span the 360-390 and 385-420 nm spectral regions using two light emitting diodes (LED) and a grating spectrometer with charge-coupled device (CCD) detector. We determined aerosol extinction cross-sections and directly observed Mie scattering resonances for aerosols that are purely scattering (polystyrene latex spheres and ammonium sulfate), slightly absorbing (Suwannee River fulvic acid), and strongly absorbing (nigrosin dye). We describe an approach for retrieving refractive indices as a function of wavelength from the measured extinction cross-sections over the 360-420 nm wavelength region. The retrieved refractive indices for PSL and ammonium sulfate agree within uncertainty with literature values for this spectral region. The refractive index determined for nigrosin is 1.78 (±0.03) + 0.19 (±0.08) i at 360 nm and 1.53 (±0.03) + 0.21 (±0.05) i at 420 nm. The refractive index determined for Suwannee River fulvic acid is 1.71 (±0.02) + 0.07 (±0.06) i at 360 nm and 1.66 (±0.02) + 0.06 (±0.04) i at 420 nm. These laboratory results support the potential for a field instrument capable of determining ambient aerosol optical extinction, average aerosol extinction cross-section, and complex refractive index as a function of wavelength.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    Aerosols influence the Earth's radiative budget by scattering and absorbing incoming solar radiation. The optical properties of aerosols vary as a function of wavelength, but few measurements have reported the wavelength dependence of aerosol extinction cross sections and complex refractive indices. We describe a new laboratory instrument to measure aerosol optical extinction as a function of wavelength, using cavity enhanced spectroscopy with a broadband light source. The instrument consists of two broadband channels which span the 360-390 and 385-420 nm spectral regions using two light emitting diodes (LED) and a grating spectrometer with charge-coupled device (CCD) detector. We determined aerosol extinction cross sections and directly observed Mie scattering resonances for aerosols that are purely scattering (polystyrene latex spheres and ammonium sulfate), slightly absorbing (Suwannee River fulvic acid), and strongly absorbing (nigrosin dye). We describe an approach for retrieving refractive indices as a function of wavelength from the measured extinction cross sections over the 360-420 nm wavelength region. The retrieved refractive indices for PSL and ammonium sulfate agree within uncertainty with the literature values for this spectral region. The refractive index determined for nigrosin is 1.78 (± 0.03) + 0.19 (± 0.08)i at 360 nm and 1.63 (± 0.03) + 0.21 (± 0.05)i at 420 nm. The refractive index determined for Suwannee River fulvic acid is 1.71 (± 0.02) + 0.07 (± 0.06)i at 360 nm and 1.66 (± 0.02) + 0.06 (± 0.04)i at 420 nm. These laboratory results support the potential for a field instrument capable of determining ambient aerosol optical extinction, average aerosol extinction cross section, and complex refractive index as a function of wavelength.

  5. Contributions of dust and smoke to aerosol extinction coefficient

    NASA Astrophysics Data System (ADS)

    Kavouras, I. G.; Xu, J.; Etyemezian, V.; Dubois, D.; Green, M.; Pitchford, M.

    2006-12-01

    Estimating scattering and absorption of light by atmospheric particles is critical for evaluating effects on regional and global climate. The magnitude of the interaction between aerosol and light is strongly related to the aerosol chemical composition among other factors. Dust and smoke are major sources of atmospheric aerosol, especially in the western United States. The importance of those sources has increased in recent decades due to the extensive man-made disturbance of natural ecosystems and land management practices. The objectives of this study were to specifically estimate the impact of dust and smoke on aerosol extinction coefficient measured in the Class I areas of the western states and identify the major causes of dust and types of smoke by using: (i) positive matrix factorization (PMF) to apportion ambient aerosols by source type; (ii) air mass backward trajectory analyses; (iii) land use/soil properties and; (iv) wildlife/prescribed fire data. The study included sites from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network located in western United States. For days with the worst reconstructed light extinction when dust was the major component, contributions from transcontinental transport from Asia, windblown dust from local sources and regional transport from upwind sources were identified. Based on the analysis for days with smoke being the major component of aerosol visibility extinction, the contributions of the following types of fires were determined: (a) wildfires near the site ("hot" emissions); (b) wildfires upwind of the site (aged smoke); (c) agricultural burn emissions; (d) rangeland fires.

  6. Aerosol transport in the coastal environment and effects on extinction

    NASA Astrophysics Data System (ADS)

    Vignati, Elizabetta; de Leeuw, Gerrit; Berkowicz, Ruwim

    1998-11-01

    The aerosol in the coastal environment consists of a complicated mixture of anthropogenic and rural aerosol generated over land, and sea spray aerosol. Also, particles are generate dover sea by physical and chemical processes and the chemical composition may change due to condensation/evaporation of gaseous materials. The actual composition is a function of air mass history and fetch. At the land-sea transition the continental sources cease to exist, and thus the concentrations of land-based particles and gases will gradually decrease. At the same time, sea spray is generated due to the interaction between wind and waves in a developing wave field. A very intense source for sea spray aerosol is the surf zone. Consequently, the aerosol transported over sea in off-shore winds will abruptly charge at the land-sea transition and then gradually loose its continental character, while also the contribution of the surf-generated aerosol will decrease. The latter will be compensated, at least in part, by the production of sea spray aerosol. A Coastal Aerosol Transport model is being developed describing the evolution of the aerosol size distribution in an air column advected from the coast line over sea in off-shore winds. Both removal and production are taken into account. The result are applied to estimate the effect of the changing size distribution on the extinction coefficients. In this contribution, preliminary results are presented from a study of the effects of the surf-generated aerosol and the surface production.

  7. Recent Improvements to CALIOP Level 3 Aerosol Profile Product for Global 3-D Aerosol Extinction Characterization

    NASA Astrophysics Data System (ADS)

    Tackett, J. L.; Getzewich, B. J.; Winker, D. M.; Vaughan, M. A.

    2015-12-01

    With nine years of retrievals, the CALIOP level 3 aerosol profile product provides an unprecedented synopsis of aerosol extinction in three dimensions and the potential to quantify changes in aerosol distributions over time. The CALIOP level 3 aerosol profile product, initially released as a beta product in 2011, reports monthly averages of quality-screened aerosol extinction profiles on a uniform latitude/longitude grid for different cloud-cover scenarios, called "sky conditions". This presentation demonstrates improvements to the second version of the product which will be released in September 2015. The largest improvements are the new sky condition definitions which parse the atmosphere into "cloud-free" views accessible to passive remote sensors, "all-sky" views accessible to active remote sensors and "cloudy-sky" views for opaque and transparent clouds which were previously inaccessible to passive remote sensors. Taken together, the new sky conditions comprehensively summarize CALIOP aerosol extinction profiles for a broad range of scientific queries. In addition to dust-only extinction profiles, the new version will include polluted-dust and smoke-only extinction averages. A new method is adopted for averaging dust-only extinction profiles to reduce high biases which exist in the beta version of the level 3 aerosol profile product. This presentation justifies the new averaging methodology and demonstrates vertical profiles of dust and smoke extinction over Africa during the biomass burning season. Another crucial advancement demonstrated in this presentation is a new approach for computing monthly mean aerosol optical depth which removes low biases reported in the beta version - a scenario unique to lidar datasets.

  8. Improvement of Raman lidar algorithm for quantifying aerosol extinction

    NASA Technical Reports Server (NTRS)

    Russo, Felicita; Whiteman, David; Demoz, Belay; Hoff, Raymond

    2005-01-01

    Aerosols are particles of different composition and origin and influence the formation of clouds which are important in atmospheric radiative balance. At the present there is high uncertainty on the effect of aerosols on climate and this is mainly due to the fact that aerosol presence in the atmosphere can be highly variable in space and time. Monitoring of the aerosols in the atmosphere is necessary to better understanding many of these uncertainties. A lidar (an instrument that uses light to detect the extent of atmospheric aerosol loading) can be particularly useful to monitor aerosols in the atmosphere since it is capable to record the scattered intensity as a function of altitude from molecules and aerosols. One lidar method (the Raman lidar) makes use of the different wavelength changes that occur when light interacts with the varying chemistry and structure of atmospheric aerosols. One quantity that is indicative of aerosol presence is the aerosol extinction which quantifies the amount of attenuation (removal of photons), due to scattering, that light undergoes when propagating in the atmosphere. It can be directly measured with a Raman lidar using the wavelength dependence of the received signal. In order to calculate aerosol extinction from Raman scattering data it is necessary to evaluate the rate of change (derivative) of a Raman signal with respect to altitude. Since derivatives are defined for continuous functions, they cannot be performed directly on the experimental data which are not continuous. The most popular technique to find the functional behavior of experimental data is the least-square fit. This procedure allows finding a polynomial function which better approximate the experimental data. The typical approach in the lidar community is to make an a priori assumption about the functional behavior of the data in order to calculate the derivative. It has been shown in previous work that the use of the chi-square technique to determine the most

  9. Preliminary tropospheric ozone DIAL, water vapour, and aerosol lidar measurements during ARC-IONS

    NASA Astrophysics Data System (ADS)

    Strawbridge, Kevin B.; Firanski, Bernard J.

    2009-09-01

    A new lidar instrument, dubbed AeRO (Aerosol Raman Ozone) Lidar, is being developed at Environment Canada's Centre For Atmospheric Research Experiments (CARE). The new system will use three lasers to simultaneously measure ozone, water vapour and aerosol profiles (including extinction) from near ground to the tropopause. The main thrust will focus on understanding Air Quality within the airshed with the capability of looking at Stratospheric Tropospheric Exchange (STE) processes to determine the magnitude and frequency of such events leading to elevated levels of tropospheric ozone. In addition a wind profiler through a partnership with University of Western Ontario will soon be deployed to CARE to provide complementary observations of the tropopause. The lidar participated in the ARC-IONS field campaign during April and July of 2008. During the field campaign, daily ozonesondes were released to further compliment the lidar measurements. Details of the system design and preliminary results from the lidar measurements will be presented.

  10. Applications of Sunphotometry to Aerosol Extinction and Surface Anisotropy

    SciTech Connect

    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.

  11. Applications of Sunphotometry to Aerosol Extinction and Surface Anisotropy

    NASA Technical Reports Server (NTRS)

    Tsay, S. C.; Holben, B. N.; Privette, J. L.

    2005-01-01

    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 (1) the spectral and spectrally-averaged surface albedo, and (2) 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.

  12. [Ultraviolet Mie lidar observations of aerosol extinction in a dust storm case over Macao].

    PubMed

    Liu, Qiao-jun; Cheng, A Y S; Zhu, Jian-hua; Fong, S K; Chang, S W; Tam, K S; Viseu, A

    2012-03-01

    Atmospheric aerosol over Macao was monitored by using a 355 nm Mie scattering lidar during the dust event on March 22nd, 2010. Vertical profiles of aerosol extinction coefficients were obtained and correlated with local PM10 concentration. The near-surface aerosol extinction coefficients have good agreement with PM10 concentration values. The aerosol extinction vertical profiles showed that there were distinct layers of dust aerosol concentration. The source and tracks of dust aerosol were analyzed by back-trajectory simulation. Observations showed that this lidar could run well even in dust storm episode, and it would help to further the study on aerosol properties over Macao. PMID:22582620

  13. Infrared extinction spectra of some common liquid aerosols.

    PubMed

    Carlon, H R; Anderson, D H; Milham, M E; Tarnove, T L; Frickel, R H; Sindoni, I

    1977-06-01

    Infrared extinction spectra in the 3-5-microm and 7-13-microm atmospheric window regions have been obtained for smokes of petroleum oil, sulfuric acid, and phosphoric acid of varying droplet concentration and for water fogs. Spectra were also obtained at 0.36-2.35microm for petroleum oil and sulfuric acid smokes. Experimental results were compared, for sulfuric acid and water aerosols, to calculated values obtained from the Mie theory. Agreement was as good as +/-10%. When absorbing smoke droplets are small compared to wavelength, very useful approximations apply, and droplet clouds may be spectrally simulated by thin liquid films. In such cases, the imaginary component of refractive index may be approximated directly from aerosol spectra. At 12.5-microm wavelength, water fog extinction is nearly independent of droplet size distribution, suggesting a simple scheme for measurement of total liquid water content of an optical path. PMID:20168760

  14. Solar proton impact on polar ozone and aerosols

    NASA Astrophysics Data System (ADS)

    Kasatkina, E.; Shumilov, O.; Kyro, E.; Kivi, R.

    The influence of solar proton events of Ground Level Event (GLE) type on ozone layer through the aerosol creation at high latitudes on the base of some experimental data and model simulation is discussed. For analysis we used ozone total content measurements from TOMS and ground based ozonometers installed at high latitudes (Barentsburg, corrected geomagnetic latitude: 74.9; Murmansk, 64.5; Sodankyla, 63.5). Ozonesonde data from Sodankyla observatory have also been used. A possible trigger mechanism of ozone destruction by incident solar protons including ion nucleation mechanism and heterogeneous chemistry is discussed. The model calculations of altitude distribution of CN (condensation nuclei), plausible centres of sulfate aerosol and Polar Startospheric Cloud (PSC) formation, are presented. Analysis of experimental data and model calculations permits us to explain some distinctions observed in ozone total content variations during several GLEs. For example, aerosol content increased significantly during moderate 21-24 May 1990 GLEs, when polar ozone "miniholes" (ozone total content depletions up to 20%)have been observed. Other GLEs (more intensive ones: 2 May 1998, 14 July 2000, 15 April 2001) caused no considerable enhancement in aerosol layer. In other words the value of aerosol increase during GLE depends on the spectrum of incident solar protons. These results demonstrate that only moderate GLEs can increase aerosol content significantly and cause ozone "minihole" creation.

  15. Lidar method of measurement of atmospheric extinction and ozone profiles

    NASA Technical Reports Server (NTRS)

    Cooney, J. A.

    1986-01-01

    A description of a method of measurement of atmospheric extinction and of ozone profiles by use of the backscatter signal from a monostatic lidar is given. The central feature of the procedure involves a measurement of the ratio of the Raman backscatter returns of both the oxygen and nitrogen atmospheric content. Because the ratio of the number density of both species is known to high accuracy, the measurement itself becomes a measure of the ratio of two transmissions to altitude along with a ratio of the two system constants. The calibration measurement for determining the value of the ratio of the two system constants or electro-optical conversion constants is accomplished by a lidar measurement of identical atmospheric targets while at the same time interchanging the two optical filters in the two optical channels of the receiver. More details of the procedure are discussed. Factoring this calibrated value into the measured O2/N2 profile ratio provides a measured value of the ratio of the two transmissions. Or equivalently, it provides a measurement of the difference of the two extinction coefficients at the O2 and N2 Raman wavelengths as a function of the height.

  16. Influences of tropospheric ozone and aerosols on satellite-derived UV

    NASA Astrophysics Data System (ADS)

    McKenzie, Richard

    2003-06-01

    In recent years the availability and quality of UV radiation data have improved appreciably. However, high quality measurements from intercalibrated ground-based spectrometers are available at only a few sites worldwide. Satellite derived UV irradiances, on the other hand, offer the advantages of global coverage and avoid the problems of instrument intercalibrations when investigating geographic differences in UV. However, with the satellite sensors in common use, the retrievals can be subject to errors due to variability in the distribution of ozone and aerosols in the lower atmosphere. Previous studies have shown good agreement between satellite-derived UV and ground-based measurements at pristine locations, but with increasing overestimations of the surface UV at more polluted sites, which are characterized by larger concentrations of ozone and aerosols in the troposphere. Consequently, the contrast in UV between pristine locations and more polluted locations may be underestimated by the satellite retrievals. Here we investigate the relative contribution to these differences due ozone profile differences and aerosol extinction. It is found that both factors contribute to the errors, but that the aerosol effect dominates. Tropospheric aerosols can result in satellite overestimations exceeding 30% in populated regions. Large concentrations of tropospheric ozone also lead to satellite overestimations. Firstly, the total ozone column would be underestimated, and secondly, the underestimated component is disproportionately important because of the increased path length and warmer temperatures in the troposphere. If tropospheric ozone were less than expected, as in more pristine locations, then there would be a tendency for satellite-derived UV to be too large by up to ~ 5%.

  17. Airborne DOAS measurements in Arctic: vertical distributions of aerosol extinction coefficient and NO2 concentration

    NASA Astrophysics Data System (ADS)

    Merlaud, A.; van Roozendael, M.; Theys, N.; Fayt, C.; Hermans, C.; Quennehen, B.; Schwarzenboeck, A.; Ancellet, G.; Pommier, M.; Pelon, J.; Burkhart, J.; Stohl, A.; de Mazière, M.

    2011-05-01

    We report airborne differential optical absorption spectroscopy (DOAS) measurements of aerosol extinction and NO2 tropospheric profiles performed off the North coast of Norway in April 2008. The DOAS instrument was installed on the Safire ATR-42 aircraft during the POLARCAT-France spring campaign and recorded scattered light spectra in near-limb geometry using a scanning telescope. We use O4 slant column measurements to derive the aerosol extinction at 360 nm. Regularization is based on the maximum a posteriori solution, for which we compare a linear and a logarithmic approach. The latter inherently constrains the solution to positive values and yields aerosol extinction profiles more consistent with independently measured size distributions. Two soundings are presented, performed on 8 April 2008 above 71° N, 22° E and on 9 April 2008 above 70° N, 17.8° E. The first profile shows aerosol extinction and NO2 in the marine boundary layer with respective values of 0.04±0.005 km-1 and 1.9±0.3 × 109 molec cm-3. A second extinction layer of 0.01±0.003 km-1 is found at 4 km altitude. During the second sounding, clouds prevented us to retrieve profile parts under 3 km altitude but a layer with enhanced extinction (0.025±0.005 km-1) and NO2 (1.95±0.2 × 109 molec cm-3) is clearly detected at 4 km altitude. From CO and ozone in-situ measurements complemented by back-trajectories, we interpret the measurements in the free troposphere as, for the first sounding, a mix between stratospheric and polluted air from Northern Europe and for the second sounding, polluted air from Central Europe containing NO2. Considering the boundary layer measurements of the first flight, modeled source regions indicate closer sources, especially the Kola Peninsula smelters, which can explain the NO2 enhancement not correlated with a CO increase at the same altitude.

  18. Airborne DOAS measurements in Arctic: vertical distributions of aerosol extinction coefficient and NO2 concentration

    NASA Astrophysics Data System (ADS)

    Merlaud, A.; van Roozendael, M.; Theys, N.; Fayt, C.; Hermans, C.; Quennehen, B.; Schwarzenboeck, A.; Ancellet, G.; Pommier, M.; Pelon, J.; Burkhart, J.; Stohl, A.; de Mazière, M.

    2011-09-01

    We report on airborne Differential Optical Absorption Spectroscopy (DOAS) measurements of aerosol extinction and NO2 tropospheric profiles performed off the North coast of Norway in April 2008. The DOAS instrument was installed on the Safire ATR-42 aircraft during the POLARCAT-France spring campaign and recorded scattered light spectra in near-limb geometry using a scanning telescope. We use O4 slant column measurements to derive the aerosol extinction at 360 nm. Regularization is based on the maximum a posteriori solution, for which we compare a linear and a logarithmic approach. The latter inherently constrains the solution to positive values and yields aerosol extinction profiles more consistent with independently measured size distributions. We present results from two soundings performed on 8 April 2008 above 71° N, 22° E and on 9 April 2008 above 70° N, 17.8° E. The first profile shows aerosol extinction and NO2 in the marine boundary layer with respective values of 0.04 ± 0.005 km-1 and 1.9 ± 0.3 × 109 molec cm-3. A second extinction layer of 0.01 ± 0.003 km-1 is found at 4 km altitude where the NO2 concentration is 0.32 ± 0.2 × 109 molec cm-3. During the second sounding, clouds prevent retrieval of profile parts under 3 km altitude but a layer with enhanced extinction (0.025 ± 0.005 km-1) and NO2 (1.95 ± 0.2 × 109 molec cm-3) is clearly detected at 4 km altitude. From CO and ozone in-situ measurements complemented by back-trajectories, we interpret the measurements in the free troposphere as, for the first sounding, a mix between stratospheric and polluted air from Northern Europe and for the second sounding, polluted air from Central Europe containing NO2. Considering the boundary layer measurements of the first flight, modeled source regions indicate closer sources, especially the Kola Peninsula smelters, which can explain the NO2 enhancement not correlated with a CO increase at the same altitude.

  19. Surface ozone-aerosol behaviour and atmospheric boundary layer structure in Saharan dusty scenario

    NASA Astrophysics Data System (ADS)

    Adame, Jose; Córdoba-Jabonero, Carmen; Sorrribas, Mar; Gil-Ojeda, Manuel; Toledo, Daniel; Yela, Margarita

    2016-04-01

    A research campaign was performed for the AMISOC (Atmospheric Minor Species relevant to the Ozone Chemistry) project at El Arenosillo observatory (southwest Spain) in May-June 2012. The campaign focused on the impact of Saharan dust intrusions at the Atmospheric Boundary Layer (ABL) and ozone-aerosol interactions. In-situ and remote-sensing techniques for gases and aerosols were used moreover to modelling analyses. Meteorology features, ABL structures and evolution, aerosol profiling distributions and aerosol-ozone interactions on the surface were analysed. Two four-day periods were selected according to non-dusty (clean conditions) and dusty (Saharan dust) situations. In both scenarios, sea-land breezes developed in the lower atmosphere, but differences were found in the upper levels. Results show that surface temperatures were greater than 3°C and humidity values were lower during dusty conditions than non-dusty conditions. Thermal structures on the surface layer (estimated using an instrument on a 100 m tower) show differences, mainly during nocturnal periods with less intense inversions under dusty conditions. The mixing layer during dusty days was 400-800 m thick, less than observed on non-dusty days. Dust also disturbed the typical daily ABL evolution. Stable conditions were observed during the early evening during intrusions. Aerosol extinction on dusty days was 2-3 times higher, and the dust was confined between 1500 and 5500 m. Back trajectory analyses confirmed that the dust had an African origin. On the surface, the particle concentration was approximately 3.5 times higher during dusty events, but the local ozone did not exhibit any change. The arrival of Saharan dust in the upper levels impacted the meteorological surface, inhibited the daily evolution of the ABL and caused an increase in aerosol loading on the surface and at higher altitudes; however, no dust influence was observed on surface ozone.

  20. Comparison of aerosol extinction profiles from lidar and SAGE II data at a tropical station

    NASA Technical Reports Server (NTRS)

    Parameswaran, K.; Rose, K. O.; Murthy, B. V. K.; Osborn, M. T.; Mcmaster, L. R.

    1991-01-01

    Aerosol extinction profiles obtained from lidar data at Trivandrum (8.6 deg N, 77 deg E) are compared with corresponding Stratospheric Aerosol and Gas Experiment II extinction profiles. The agreement between the two is found to be satisfactory. The extinction profiles obtained by both the experiments showed a prominent peak at 23-24 km altitude in the stratosphere. The study revealed large variability in upper tropospheric extinction with location (latitude).

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

    NASA Astrophysics Data System (ADS)

    Han, Zaw; Wu, Yonghua; Moshary, Fred; Gross, Barry; Gilerson, Alex

    2016-06-01

    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.

  2. In situ measurements of light extinction of stratospheric aerosols

    NASA Technical Reports Server (NTRS)

    Metzig, Gunthard

    1991-01-01

    The extinction coefficient of ambient aerosol particles was measured using a multiple transverse cell (White Cell) with an effective path length of 100 m. Measurements were performed at seven fixed wavelengths in the visible region using a white light source and an interference filter set with 2 nm bandwidth and center wavelengths of 405.5, 450, 500, 550, 600, 650, and 692.5 nm. The total air flow in the system was 16.7 1/min; the volume of the chamber is close to 10 liters. It takes about one minute to fill the chamber with particles homogeneously, but it needs up to five minutes to get the chamber particle-free. Before measuring the aerosol, the transmission of the particle-free air is determined; then the aerosol passes through the chamber for a period of ten minutes; after this the transmission of particle-free ambient air is measured again for eight minutes. All times are subject to change. At present the measurements are done with a frequency of 1 Hz, but an increase of up to 30 Hz is possible. The lower detection limit of the used White Cell is 3.4 by 10(exp -06) per m. This is sufficient for measuring the extinction coefficient during most tropospheric and some stratospheric conditions. It will be necessary to increase the sensitivity by a factor of ten when measurements under the clearest stratospheric conditions take place.

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

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  4. Amazon basin ozone and aerosol: Wet season observations

    SciTech Connect

    Gregory, G.L.; Browell, E.V.; Warren, L.S.; Hudgins, C.H. )

    1990-09-20

    The tropical environment is recognized as having a major impact on global tropospheric chemistry. The data show that the wet season Amazon Basin is an effective sink for ozone and a net source for aerosols. Mixed layer ozone at 150-m altitude averaged 8.5 ppbv compared to about 18 ppbv at 3-km altitude. In addition, a negative ozone gradient (decreasing value to the surface) was observed within the mixed layer. The averaged wet season mixed layer ozone was about 7 ppbv lower than observed during the dry season. This is attributed to the enhanced convective activity associated with the wet season and the change in mixed layer photochemistry from net ozone production (dry season) to a net destruction (wet season). The net sink characteristics of the wet season mixed layer are seen throughout the troposphere of the Amazon Basin in that ozone (3- to 4-km altitude) is typically 15-25 ppbv as compared to dry season values of 30-35 ppbv. In terms of the aerosol source characteristics of the Amazon Basin, mixed layer aerosols (0.1- to 0.4-{mu}m diameter) are a factor of 5-10 higher than observed in the troposphere with mixed layer values of 100-200 aerosols/cm{sup 3}. Analyses of both tropospheric and mixed layer aerosol samples show aerosols which are multisource. Tropospheric samples have size distributions which are trimodal and show modes at aerosol diameters which suggest the aerosols are (1) of lifetimes <1 hour, (2) of lifetimes of days, and (3) mechanically generated elements (e.g., wind-blow dust). Mixed layer data show two of the three modes with no mode which represent aerosols with lifetimes of days.

  5. Miniature instruments for aerosol extinction at ambient conditions

    NASA Astrophysics Data System (ADS)

    Murphy, D. M.

    2015-12-01

    Aerosol extinction is a fundamental parameter for the direct forcing of climate, visibility, and comparisons to remote sensing. Bringing air into an instrument "box" almost always changes the relative humidity and loses some dust or other large particles. I will show two techniques for miniature instruments that measure extinction at ambient conditions. One is a miniature sun photometer for vertical profiles. In the last year it has successfully gathered data on test flights with excellent performance and signal to noise. The second instrument is a miniature cavity ring down instrument open to the air. In both cases, small instruments require decisions about just what is necessary for the measurement rather than just scaling down larger designs. I will explore the rationale for some of these design choices.

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  8. Photoacoustic determination of optical absorption to extinction ratio in aerosols.

    PubMed

    Roessler, D M; Faxvog, F R

    1980-02-15

    The photoacoustic technique has been used in conjunction with an optical transmission measurement to determine the fraction of light absorbed in cigarette and acetylene smoke aerosols. At 0.5145-microm wavelength,the absorption-to-extinction fraction is 0.01 +/- 0.003 for cigarette smoke and is in excellent agreement with predictions from Mie theory for smoke particles having a refractive index of 1.45-0.00133i and a median diameter in the 0.15-0.65-microm range. For acetylene smoke the absorbed fraction was 0.85 +/- 0.05. PMID:20216896

  9. Evaluation of atmospheric aerosol and tropospheric ozone effects on global terrestrial ecosystem carbon dynamics

    NASA Astrophysics Data System (ADS)

    Chen, Min

    The increasing human activities have produced large amounts of air pollutants ejected into the atmosphere, in which atmospheric aerosols and tropospheric ozone are considered to be especially important because of their negative impacts on human health and their impacts on global climate through either their direct radiative effect or indirect effect on land-atmosphere CO2 exchange. This dissertation dedicates to quantifying and evaluating the aerosol and tropospheric ozone effects on global terrestrial ecosystem dynamics using a modeling approach. An ecosystem model, the integrated Terrestrial Ecosystem Model (iTem), is developed to simulate biophysical and biogeochemical processes in terrestrial ecosystems. A two-broad-band atmospheric radiative transfer model together with the Moderate-Resolution Imaging Spectroradiometer (MODIS) measured atmospheric parameters are used to well estimate global downward solar radiation and the direct and diffuse components in comparison with observations. The atmospheric radiative transfer modeling framework were used to quantify the aerosol direct radiative effect, showing that aerosol loadings cause 18.7 and 12.8 W m -2 decrease of direct-beam Photosynthetic Active Radiation (PAR) and Near Infrared Radiation (NIR) respectively, and 5.2 and 4.4 W m -2 increase of diffuse PAR and NIR, respectively, leading to a total 21.9 W m-2 decrease of total downward solar radiation over the global land surface during the period of 2003-2010. The results also suggested that the aerosol effect may be overwhelmed by clouds because of the stronger extinction and scattering ability of clouds. Applications of the iTem with solar radiation data and with or without considering the aerosol loadings shows that aerosol loading enhances the terrestrial productions [Gross Primary Production (GPP), Net Primary Production (NPP) and Net Ecosystem Production (NEP)] and carbon emissions through plant respiration (RA) in global terrestrial ecosystems over the

  10. Comparison of aerosol extinction between lidar and SAGE II over Gadanki, a tropical station in India

    NASA Astrophysics Data System (ADS)

    Kulkarni, P.; Ramachandran, S.

    2015-03-01

    An extensive comparison of aerosol extinction has been performed using lidar and Stratospheric Aerosol and Gas Experiment (SAGE) II data over Gadanki (13.5° N, 79.2° E), a tropical station in India, following coincident criteria during volcanically quiescent conditions from 1998 to 2005. The aerosol extinctions derived from lidar are higher than SAGE II during all seasons in the upper troposphere (UT), while in the lower-stratosphere (LS) values are closer. The seasonal mean percent differences between lidar and SAGE II aerosol extinctions are > 100% in the UT and < 50% above 25 km. Different techniques (point and limb observations) played the major role in producing the observed differences. SAGE II aerosol extinction in the UT increases as the longitudinal coverage is increased as the spatial aerosol extent increases, while similar extinction values in LS confirm the zonal homogeneity of LS aerosols. The study strongly emphasized that the best meteorological parameters close to the lidar measurement site in terms of space and time and Ba (sr-1), the ratio between aerosol backscattering and extinction, are needed for the tropics for a more accurate derivation of aerosol extinction.

  11. Measurements of stratospheric ozone and aerosols above Spitsbergen

    NASA Technical Reports Server (NTRS)

    Neuber, Roland; Beyerle, Georg; Schrems, Otto; Fabian, Rolf; Vondergathen, Peter; Krueger, Bernd C.

    1994-01-01

    Stratospheric ozone and aerosol data recorded at Spitsbergen (79 deg N, 12 deg E) from 1988 to 1992 are presented. Strong dynamical influences like seasonal variations and annual cycles in the ozone concentrations are described. Polar Stratospheric Clouds were detected above Spitsbergen in January 1989 and 1990, but not in the next two years. Volcanic aerosols, attributed to the Mt. Pinatubo eruption, appeared as early as August 1991 above Spitsbergen and were a constant feature of the lower Arctic stratosphere in winter 1991/92.

  12. Retrieving Stratospheric Aerosol Extinction from SCIAMACHY Measurements in Limb Geometry

    NASA Astrophysics Data System (ADS)

    Dörner, Steffen; Penning de Vries, Marloes; Pukite, Janis; Beirle, Steffen; Wagner, Thomas

    2015-04-01

    Techniques for retrieving height resolved information on stratospheric aerosol improved significantly in the past decade with the availability of satellite measurements in limb geometry. Instruments like OMPS, OSIRIS and SCIAMACHY provide height resolved radiance spectra with global coverage. Long term data sets of stratospheric aerosol extinction profiles are important for a detailed investigation of spatial and temporal variation and formation processes (e.g. after volcanic eruptions or in polar stratospheric clouds). Resulting data sets contain vital information for climate models (radiative effect) or chemistry models (reaction surface for heterogeneous chemistry). This study focuses on the SCIAMACHY instrument which measured scattered sunlight in the ultra-violet, visible and near infra-red spectral range since the launch on EnviSat in 2002 until an instrumental error occurred in April 2012. SCIAMACHY's unique method of alternating measurements in limb and nadir geometry provides co-located profile and column information respectively that can be used to characterize plumes with small horizontal extents. The covered wavelength range potentially provides information on effective micro-physical properties of the aerosol particles. However, scattering on background aerosol constitutes only a small fraction of detected radiance and assumptions on particle characteristics (e.g. size distribution) have to be made which results in large uncertainties especially for wavelengths below 700nm and for measurements in backscatter geometry. Methods to reduce these uncertainties are investigated and applied to our newly developed retrieval algorithm. In addition, so called spatial straylight contamination of the measured signal was identified as a significant error source and an empirical correction scheme was developed. A large scale comparison study with SAGE II for the temporal overlap of both instruments (2002 to 2005) shows promising results.

  13. Extinction spectra of mineral dust aerosol components in an environmental aerosol chamber: IR resonance studies

    NASA Astrophysics Data System (ADS)

    Mogili, Praveen K.; Yang, K. H.; Young, Mark A.; Kleiber, Paul D.; Grassian, Vicki H.

    Mineral dust aerosol plays an important role in determining the physical and chemical equilibrium of the atmosphere. To better understand the impact that mineral dust aerosol may have on climate forcing and on remote sensing, we have initiated a study of the optical properties of important components of mineral dust aerosol including silicate clays (illite, kaolinite, and montmorillonite), quartz, anhydrite, and calcite. The extinction spectra are measured in an environmental simulation chamber over a broad wavelength range, which includes both the IR (650-5000 cm -1) and UV-vis (12,500-40,000 cm -1) spectral regions. In this paper, we focus on the IR region from 800 to 1500 cm -1, where many of these mineral dust constituents have characteristic vibrational resonance features. Experimental spectra are compared with Mie theory simulations based on published mineral optical constants. We find that Mie theory generally does a poor job in fitting the IR resonance peak positions and band profiles for nonspherical aerosols in the accumulation mode size range ( D˜0.1-2.5 μm). We explore particle shape effects on the IR resonance line profiles by considering analytic models for extinction of particles with characteristic shapes (i.e. disks, needles, and ellipsoids). Interestingly, Mie theory often appears to give more accurate results for the absorption line profiles of larger particles that fall in the coarse mode size range.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  15. SAGE II/Umkehr ozone comparisons and aerosols effects: An empirical and theoretical study. Final report

    SciTech Connect

    Newchurch, M.

    1997-09-15

    The objectives of this research were to: (1) examine empirically the aerosol effect on Umkehr ozone profiles using SAGE II aerosol and ozone data; (2) examine theoretically the aerosol effect on Umkehr ozone profiles; (3) examine the differences between SAGE II ozone profiles and both old- and new-format Umkehr ozone profiles for ozone-trend information; (4) reexamine SAGE I-Umkehr ozone differences with the most recent version of SAGE I data; and (5) contribute to the SAGE II science team.

  16. Determination of aerosol extinction coefficient profiles from LIDAR data using the optical depth solution method

    NASA Astrophysics Data System (ADS)

    Aparna, John; Satheesh, S. K.; Mahadevan Pillai, V. P.

    2006-12-01

    The LIDAR equation contains four unknown variables in a two-component atmosphere where the effects caused by both molecules and aerosols have to be considered. The inversion of LIDAR returns to retrieve aerosol extinction profiles, thus, calls for some functional relationship to be assumed between these two. The Klett's method, assumes a functional relationship between the extinction and backscatter. In this paper, we apply a different technique, called the optical depth solution, where we made use of the total optical depth or transmittance of the atmosphere along the LIDAR-measurement range. This method provides a stable solution to the LIDAR equation. In this study, we apply this technique to the data obtained using a micro pulse LIDAR (MPL, model 1000, Science and Engineering Services Inc) to retrieve the vertical distribution of aerosol extinction coefficient. The LIDAR is equipped with Nd-YLF laser at an operating wavelength of 523.5 nm and the data were collected over Bangalore. The LIDAR data are analyzed to get to weighted extinction coefficient profiles or the weighted sum of aerosol and molecular extinction coefficient profiles. Simultaneous measurements of aerosol column optical depth (at 500 nm) using a Microtops sun photometer were used in the retrievals. The molecular extinction coefficient is determined assuming standard atmospheric conditions. The aerosol extinction coefficient profiles are determined by subtracting the molecular part from the weighted extinction coefficient profiles. The details of the method and the results obtained are presented.

  17. Can we predict aerosol extinction in a coastal environment?

    NASA Astrophysics Data System (ADS)

    Tsintikidis, Dimitri; Kichura, Dan; Hammel, Steve

    2007-09-01

    We have been engaged in a long-term test to determine the beam extinction effects of aerosols. During four test periods of one month duration each, we propagated a beam over a 7-km path near the ocean surface, and measured the received intensity in two near-infrared wavebands (1.061 μm and at 1.622 μm). In each test period, meteorological measurements were obtained from a meteorological buoy located at the mid-point of the propagation path. These meteorological data were used as input for the Advanced Navy Aerosol Model (ANAM). In this paper we will describe the comparison between the ANAM predictions and the measured transmission. We found that there are significant and sustained discrepancies between the ANAM model predictions and the optical transmission data. We will focus on two particular problems that have emerged from our comparison: first, the ANAM dependence on local wind speed can cause errors, and second, the local relative humidity is not optimally coupled in the ANAM. We will present the analysis we used to support these claims, and we will present recommendations for modifications to the model.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  19. The Impact of Geoengineering Aerosols on Stratospheric Temperature and Ozone

    NASA Technical Reports Server (NTRS)

    Heckendorn, P.; Weisenstein, D.; Fueglistaler, S.; Luo, B. P.; Rozanov, E.; Schraner, M.; Peter, T.; Thomason, L. W.

    2009-01-01

    Anthropogenic greenhouse gas emissions are warming the global climate at an unprecedented rate. Significant emission reductions will be required soon to avoid a rapid temperature rise. As a potential interim measure to avoid extreme temperature increase, it has been suggested that Earth's albedo be increased by artificially enhancing stratospheric sulfate aerosols. We use a 3D chemistry climate model, fed by aerosol size distributions from a zonal mean aerosol model, to simulate continuous injection of 1-10 Mt/a into the lower tropical stratosphere. In contrast to the case for all previous work, the particles are predicted to grow to larger sizes than are observed after volcanic eruptions. The reason is the continuous supply of sulfuric acid and hence freshly formed small aerosol particles, which enhance the formation of large aerosol particles by coagulation and, to a lesser extent, by condensation. Owing to their large size, these particles have a reduced albedo. Furthermore, their sedimentation results in a non-linear relationship between stratospheric aerosol burden and annual injection, leading to a reduction of the targeted cooling. More importantly, the sedimenting particles heat the tropical cold point tropopause and, hence, the stratospheric entry mixing ratio of H2O increases. Therefore, geoengineering by means of sulfate aerosols is predicted to accelerate the hydroxyl catalyzed ozone destruction cycles and cause a significant depletion of the ozone layer even though future halogen concentrations will be significantly reduced.

  20. The Impact of Geoengineering Aerosols on Stratospheric Temperature and Ozone

    NASA Technical Reports Server (NTRS)

    Heckendorn, P.; Weisenstein, D.; Fueglistaler, S.; Luo, B. P.; Rozanov, E.; Schraner, M.; Thomason, L. W.; Peter, T.

    2011-01-01

    Anthropogenic greenhouse gas emissions are warming the global climate at an unprecedented rate. Significant emission reductions will be required soon to avoid a rapid temperature rise. As a potential interim measure to avoid extreme temperature increase, it has been suggested that Earth's albedo be increased by artificially enhancing stratospheric sulfate aerosols. We use a 3D chemistry climate model, fed by aerosol size distributions from a zonal mean aerosol model. to simulate continuous injection of 1-10 Mt/a into the lower tropical stratosphere. In contrast to the case for all previous work, the particles are predicted to grow to larger sizes than are observed after volcanic eruptions. The reason is the continuous supply of sulfuric acid and hence freshly formed small aerosol particles, which enhance the formation of large aerosol particles by coagulation and, to a lesser extent, by condensation. Owing to their large size, these particles have a reduced albedo. Furthermore, their sedimentation results in a non-linear relationship between stratospheric aerosol burden and annual injection, leading to a reduction of the targeted cooling. More importantly, the sedimenting particles heat the tropical cold point tropopause and, hence, the stratospheric entry mixing ratio of H2O increases. Therefore, geoengineering by means of sulfate aerosols is predicted to accelerate the hydroxyl catalyzed ozone destruction cycles and cause a significant depletion of the ozone layer even though future halogen concentrations will he significantly reduced.

  1. Optical modeling of aerosol extinction for remote sensing in the marine environment

    NASA Astrophysics Data System (ADS)

    Kaloshin, G. A.

    2013-05-01

    A microphysical model is presented for the surface layer marine and coastal atmospheric aerosols that is based on long-term observations of size distributions for 0.01-100 μm particles in different geographic sites. The fundamental feature of the model is a parameterization of amplitudes and widths for aerosol modes of the aerosol size distribution function (ASDF) as functions of fetch and wind speed. The shape of the ASDF and its dependence on meteorological parameters, altitudes above sea level (H), fetch (X), wind speed (U) and relative humidity (RH) are investigated. The spectral profiles of the aerosol extinction coefficients calculated by MaexPro (Marine Aerosol Extinction Profiles) are in good agreement with observational data and the numerical results obtained from the Navy Aerosol Model (NAM) and the Advanced Navy Aerosol Model (ANAM). Moreover, MaexPro was found to be an accurate and reliable tool for investigation of the optical properties of atmospheric aerosols.

  2. Autonomous Ozone and Aerosol Lidar Platform: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Strawbridge, K. B.

    2014-12-01

    Environment Canada is developing an autonomous tropospheric ozone and aerosol lidar system for deployment in support of short-term field studies. Tropospheric ozone and aerosols (PM10 and PM2.5) are important atmospheric constituents in low altitude pollution affecting human health and vegetation. Ozone is photo-chemically active with nitrogen oxides and can have a distinct diurnal variability. Aerosols contribute to the radiative budget, are a tracer for pollution transport, undergo complex mixing, and contribute to visibility and cloud formation. This particular instrument will employ two separate lidar transmitter and receiver assemblies. The tropospheric ozone lidar, based on the differential absorption lidar (DIAL) technique, uses the fourth harmonics of a Nd:YAG laser directed into a CO2 Raman cell to produce 276 nm, 287nm and 299 nm (first to third Stokes lines) output wavelengths. The aerosol lidar is based on the 3+2 design using a tripled Nd:YAG to output 355 nm, 532 nm and 1064nm wavelengths. Both lidars will be housed in a modified cargo trailer allowing for easy deployment to remote areas. The unit can be operated and monitored 24 hours a day via an internet link and requires an external power source. Simultaneous ozone and aerosol lidar measurements will provide the vertical context necessary to understand the complex mixing and transformation of pollutants - particularly when deployed near other ground-based in-situ sensors. Preliminary results will be shown from a summer field study at the Centre For Atmospheric Research Experiments (CARE).

  3. Synergistic effects of air pollutants: Ozone plus a respirable aerosol

    SciTech Connect

    Last, J.A. )

    1991-01-01

    Rats were concurrently exposed to mixtures of ozone or nitrogen dioxide and respirable-sized aerosols of sulfuric acid, ammonium sulfate, or sodium chloride, or to each pollutant individually. Their responses to such exposures were evaluated by various quantitative biochemical analyses of lung tissue or lavage fluids, or by morphometric analyses. Such studies were performed in the acute time frame, generally involving exposures of from one to nine days, depending on the assays used. Correlations between the biochemical and morphometric results were examined over a wide range of pollutant concentrations in the exposure chambers. Good correlations were found between the most sensitive biochemical indicators of lung damage--the protein content of lung lavage fluid or whole lung tissue and the rate of lung collagen synthesis--and the morphometric estimation of volume density or volume percent of the centriacinar lung lesion characteristically observed in animals exposed to ozone. Synergistic interaction between ozone and sulfuric acid aerosol was demonstrated to occur at environmentally relevant concentrations of both pollutants by several of the analytical methods used. Such interactions were demonstrated at concentrations of ozone as low as 0.12 parts per million (ppm)2 and of sulfuric acid aerosol at concentrations as low as 5 to 20 micrograms/m3. The acidity of the aerosol is a necessary (and apparently a sufficient) condition for such a synergistic interaction between an oxidant gas and a respirable aerosol to occur. A hitherto unexpected synergistic interaction between nitrogen dioxide and sodium chloride aerosol was found during these studies; it is hypothesized that this was due to formation of their acidic (anhydride) reaction product, nitrosyl chloride, in the chambers during exposure to the mixture.

  4. Ozone entrainment flux using ozone DIAL and Compact Wind Aerosol Lidar (CWAL) in Huntsville AL

    NASA Astrophysics Data System (ADS)

    Huang, G.; Newchurch, M.; kuang, S.; Wang, L.; Cantrell, W.

    2013-12-01

    Previous studies have proved that the impact of high ozone amounts in the residual layer can account for up to 80% of the surface ozone maxima during the following day. This high ozone in the residual layer mixes into to the Planetary Boundary Layer (PBL) through the entrainment processes as the growth of PBL occurs in the morning. Conversely, anthropogenic pollutants emitted from the surface mix into the Free Troposphere (FT) and are transported to other places. Therefore, entrainment flux is one of the important connections between the local-scale/urban-scale and the regional scale. In this study, we will present a study of ozone entrainment fluxes using continuous observation by co-located ozone DIAL and Compact Wind Aerosol Lidar (CWAL) at the campus of University of Alabama in Huntsville (UAH). As a part of Tropospheric Ozone Lidar NETwork (TOLNET), UAH ozone DIAL can provide continuous ozone observation at the range of 125 m AGL to 12 km, with 10-min temporal resolution and 150 - 550 m vertical resolution [Kuang et al., 2013]. We also perform an ozone budget study using Dutch Atmospheric Large-Eddy Simulation (DALES), reasonable approximations of dry deposition, in conjunction with ozone entrainment flux observations. We work towards building a comprehensive understanding of the quantitative impacts of ozone entrainment processes on surface ozone amounts in a medium-sized urban area like Huntsville AL. Shi Kuang, Michael J. Newchurch, John Burris, and Xiong Liu, "Ground-based lidar for atmospheric boundary layer ozone measurements," Appl. Opt. 52, 3557-3566 (2013)

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

    NASA Technical Reports Server (NTRS)

    Thomason, L. W.

    2012-01-01

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

  6. Ground-based lidar observations of ozone aerosol and temperature

    SciTech Connect

    Heaps, W.S.

    1987-09-01

    Several theories have been proposed to explain the recently discovered, springtime ozone depletion over Antarctica, but additional data is necessary to establish what processes are producing this phenomenon. The preliminary results of the 1986-1987 National Ozone Expedition indicate that nitrogen oxides were present smaller amounts than anticipated and that chlorine compounds were more prevalent. These findings support chemical theories based on chlorine or chlorine-bromine chemical mechanisms are affecting the level of ozone in the stratosphere; however, not all climate dynamic theories are discounted by these data. The objective is to use a ground-based laser radar system (lidar) in an upward-looking mode to record ozone profiles, aerosol content, and temperature profiles. Although the system was not principally designed for these measurements, the author has modified it slightly to collect these data.

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

    SciTech Connect

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

    1995-12-31

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

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

    NASA Technical Reports Server (NTRS)

    Want, P. H.; Deepak, A.

    1985-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  11. Mid-infrared extinction by sulfate aerosols from the Mt. Pinatubo eruption

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Yue, G. K.; Gunson, M. R.; Zander, R.; Abrams, M. C.

    1994-01-01

    Quantitative measurements of the wavelength dependence of aerosol extinction in the 750-3400/cm spectral region have been derived from 0.01/cm resolution stratospheric solar occultation spectra recorded by the ATMOS (Atmospheric Trace Molecule Spectroscopy) Fourier transform spectrometer about 9 1/2 months after the Mt Pinatubo volcanic eruption. Strong, broad aerosol features have been identified near 900, 1060, 1190, 1720, and 2900/cm below a tangent height of approximately 30 km. Aerosol extinction measurements derived from approximately 0.05/cm wide microwindows nearly free of telluric line absorption in the ATMOS spectra are compared with transmission calculations derived from aerosol size distribution profiles retrieved from correlative SAGE (Stratospheric Aerosol and Gas Experiment) II visible and near i.r. extinction measurements, seasonal and zonally averaged H2SO4 aerosol weight percentage profiles, and published sulfuric acid optical constants derived from room temperature laboratory measurements. The calculated shapes and positions of the aerosol features are generally consistent with the observations, thereby confirming that the aerosols are predominantly concentrated H2SO4-H2O droplets, but there are significant differences between the measured and calculated wavelength dependences of the aerosol extinction. We attribute these differences as primarily the result of errors in the calculated low temperature H2SO4-H2O optical constants. Errors in both the published room temperature optical constants and the limitations of the Lorentz-Lorenz relation are likely to be important.

  12. Spectral Aerosol Extinction (SpEx): a new instrument for in situ ambient aerosol extinction measurements across the UV/visible wavelength range

    NASA Astrophysics Data System (ADS)

    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.; Thornhill, K. L.; Troop, D.; Winstead, E. L.; Ziemba, L. D.

    2015-06-01

    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 (PSLs) 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. Extinction spectra obtained with SpEx contain more information than can be conveyed by a simple power law fit (typically represented by Ångström Exponents). Planned future improvements aim to lower detection limits and ruggedize the instrument for mobile operation.

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

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  14. Raman lidar measurements of aerosol extinction and backscattering: 1. Methods and comparisons

    NASA Astrophysics Data System (ADS)

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

    1998-08-01

    This paper examines the aerosol backscattering and extinction profiles measured at night by the NASA Goddard Space Flight Center Scanning Raman Lidar (SRL) during the remote cloud sensing (RCS) intensive operations period (IOP) at the Department of Energy Atmospheric Radiation Measurement (ARM) southern Great Plains (SGP) site in April 1994. These lidar data are used to derive aerosol profiles for altitudes between 0.015 and 5 km. Since this lidar detects Raman scattering from nitrogen and oxygen molecules as well as the elastic scattering from molecules and aerosols, it measures both aerosol backscattering and extinction simultaneously. The aerosol extinction/backscattering ratio varied between approximately 30 sr and 75 sr at 351 nm. Aerosol optical thicknesses derived by integrating the lidar profiles of aerosol extinction measured at night between 0.1 and 5 km are found to be about 10-40% lower than those measured by a Sun photometer during the day. This difference is attributed to the contribution by stratospheric aerosols not included in the lidar estimates as well as to diurnal differences in aerosol properties and concentrations. Aerosol profiles close to the surface were acquired by pointing the lidar nearly horizontally. Measurements of aerosol scattering from a tower-mounted nephelometer are found to be 40% lower than lidar measurements of aerosol extinction over a wide range of relative humidities even after accounting for the difference in wavelengths. The reasons for this difference are not clear but may be due to the inability of the nephelometer to accurately measure scattering by large particles.

  15. Compact Ozone Lidar for Atmospheric Ozone and Aerosol Measurements

    NASA Technical Reports Server (NTRS)

    Marcia, Joel; DeYoung, Russell J.

    2007-01-01

    A small compact ozone differential absorption lidar capable of being deployed on a small aircraft or unpiloted atmospheric vehicle (UAV) has been tested. The Ce:LiCAF tunable UV laser is pumped by a quadrupled Nd:YLF laser. Test results on the laser transmitter demonstrated 1.4 W in the IR and 240 mW in the green at 1000 Hz. The receiver consists of three photon-counting channels, which are a far field PMT, a near field UV PMT, and a green PMT. Each channel was tested for their saturation characteristics.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  17. Ozone and Aerosol Retrieval from Backscattered Ultraviolet Radiation

    NASA Technical Reports Server (NTRS)

    Bhartia, Pawan K.

    2012-01-01

    In this presentation we will discuss the techniques to estimate total column ozone and aerosol absorption optical depth from the measurements of back scattered ultraviolet (buv) radiation. The total ozone algorithm has been used to create a unique record of the ozone layer, spanning more than 3 decades, from a series of instruments (BUV, SBUV, TOMS, SBUV/2) flown on NASA, NOAA, Japanese and Russian satellites. We will discuss how this algorithm can be considered a generalization of the well-known Dobson/Brewer technique that has been used to process data from ground-based instruments for many decades, and how it differs from the DOAS techniques that have been used to estimate vertical column densities of a host of trace gases from data collected by GOME and SCIAMACHY instruments. The buv aerosol algorithm is most suitable for the detection of UV absorbing aerosols (smoke, desert dust, volcanic ash) and is the only technique that can detect aerosols embedded in clouds. This algorithm has been used to create a quarter century record of aerosol absorption optical depth using the buv data collected by a series of TOMS instruments. We will also discuss how the data from the OMI instrument launched on July 15, 2004 will be combined with data from MODIS and CALIPSO lidar data to enhance the accuracy and information content of satellite-derived aerosol measurements. The OMI and MODIS instruments are currently flying on EOS Aura and EOS Aqua satellites respectively, part of a constellation of satellites called the "A-train".

  18. Ozone and Aerosol Retrieval from Backscattered Ultraviolet Radiation

    NASA Technical Reports Server (NTRS)

    Bhartia, Pawan K.

    2004-01-01

    In this presentation we will discuss the techniques to estimate total column ozone and aerosol absorption optical depth from the measurements of backscattered ultraviolet (buv) radiation. The total ozone algorithm has been used to create a unique record of the ozone layer, spanning more than 3 decades, from a series of instruments (BUV, SBUV, TOMS, SBUV/2) flown on NASA, NOAA, Japanese and Russian satellites. We will discuss how this algorithm can be considered a generalization of the well-known Dobson/Brewer technique that has been used to process data from ground-based instruments for many decades, and how it differs from the DOAS techniques that have been used to estimate vertical column densities of a host of trace gases from data collected by GOME and SCIAMACHY instruments. The BUV aerosol algorithm is most suitable for the detection of UV absorbing aerosols (smoke, desert dust, volcanic ash) and is the only technique that can detect aerosols embedded in clouds. This algorithm has been used to create a quarter century record of aerosol absorption optical depth using the BUV data collected by a series of TOMS instruments. We will also discuss how the data from the OM1 instrument launched on July 15,2004 will be combined with data from MODIS and CALIPSO lidar data to enhance the accuracy and information content of satellite-derived aerosol measurements. The OM1 and MODIS instruments are currently flying on EOS Aura and EOS Aqua satellites respectively, part of a constellation of satellites called the "A-train". The CALIPSO satellite is expected to join this constellation in mid 2005.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  20. The code MaexPro for calculation of aerosol extinction in the marine and coastal environment

    NASA Astrophysics Data System (ADS)

    Kaloshin, G. A.

    2010-04-01

    In the paper the description of the last version of code MaexPro (Marine aerosol extinction Profile) for calculation spectral and vertical profiles of aerosol extinction coefficient α(λ), aerosol sizes distribution, area distribution, volumes distribution, modes aerosol extinction spectra is submitted. Code MaexPro is a computer program under constant development to estimate of EO systems signal power at a location place in which a fetch is key entrance parameter. The program carries out calculation α(λ), as functions of atmospheric effects using standard meteorological parameters, aerosol microphysical structure, a spectral band and a height of the sensor location. Spectral behavior α(λ) can be submitted as graphically, and as tables. Commands overplot for superposition or change of figures; profiles extrapolation; a lens; all kinds of possible copying; the data presentation, convenient for an input in code MODTRAN, and etc. are stipulated. The code MaexPro is a completely mouse-driven PC Windows program with a user-friendly interface. Calculation time of spectral and vertical profiles of α(λ) depends on the necessary wave length resolution, radius of aerosol particles and the location place height, and does not exceed tens seconds for each new meteorological condition. Other calculations characteristics, such as aerosol sizes distribution, area distribution, volumes distribution, modes aerosol extinction spectra, are performed in a few seconds.

  1. Linkages Between Ozone-depleting Substances, Tropospheric Oxidation and Aerosols

    NASA Technical Reports Server (NTRS)

    Voulgarakis, A.; Shindell, D. T.; Faluvegi, G.

    2013-01-01

    Coupling between the stratosphere and the troposphere allows changes in stratospheric ozone abundances to affect tropospheric chemistry. Large-scale effects from such changes on chemically produced tropospheric aerosols have not been systematically examined in past studies. We use a composition-climate model to investigate potential past and future impacts of changes in stratospheric ozone depleting substances (ODS) on tropospheric oxidants and sulfate aerosols. In most experiments, we find significant responses in tropospheric photolysis and oxidants, with small but significant effects on methane radiative forcing. The response of sulfate aerosols is sizeable when examining the effect of increasing future nitrous oxide (N2O) emissions. We also find that without the regulation of chlorofluorocarbons (CFCs) through the Montreal Protocol, sulfate aerosols could have increased by 2050 by a comparable amount to the decreases predicted due to relatively stringent sulfur emissions controls. The individual historical radiative forcings of CFCs and N2O through their indirect effects on methane (-22.6mW/sq. m for CFCs and -6.7mW/sq. m for N2O) and sulfate aerosols (-3.0mW/sq. m for CFCs and +6.5mW/sq. m for N2O when considering the direct aerosol effect) discussed here are non-negligible when compared to known historical ODS forcing. Our results stress the importance of accounting for stratosphere-troposphere, gas-aerosol and composition-climate interactions when investigating the effects of changing emissions on atmospheric composition and climate.

  2. Linkages between ozone-depleting substances, tropospheric oxidation and aerosols

    NASA Astrophysics Data System (ADS)

    Voulgarakis, A.; Shindell, D. T.; Faluvegi, G.

    2013-05-01

    Coupling between the stratosphere and the troposphere allows changes in stratospheric ozone abundances to affect tropospheric chemistry. Large-scale effects from such changes on chemically produced tropospheric aerosols have not been systematically examined in past studies. We use a composition-climate model to investigate potential past and future impacts of changes in stratospheric ozone depleting substances (ODS) on tropospheric oxidants and sulfate aerosols. In most experiments, we find significant responses in tropospheric photolysis and oxidants, with small but significant effects on methane radiative forcing. The response of sulfate aerosols is sizeable when examining the effect of increasing future nitrous oxide (N2O) emissions. We also find that without the regulation of chlorofluorocarbons (CFCs) through the Montreal Protocol, sulfate aerosols could have increased by 2050 by a comparable amount to the decreases predicted due to relatively stringent sulfur emissions controls. The individual historical radiative forcings of CFCs and N2O through their indirect effects on methane (-22.6 mW m-2 for CFCs and -6.7 mW m-2 for N2O) and sulfate aerosols (-3.0 mW m-2 for CFCs and +6.5 mW m-2 for N2O when considering the direct aerosol effect) discussed here are non-negligible when compared to known historical ODS forcing. Our results stress the importance of accounting for stratosphere-troposphere, gas-aerosol and composition-climate interactions when investigating the effects of changing emissions on atmospheric composition and climate.

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

    NASA Technical Reports Server (NTRS)

    Torres, O.; Bhartia, P. K.

    1998-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  5. Spectral aerosol extinction (SpEx): a new instrument for in situ ambient aerosol extinction measurements across the UV/visible wavelength range

    NASA Astrophysics Data System (ADS)

    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.; Thornhill, K. L.; Troop, D.; Winstead, E. L.; Ziemba, L. D.

    2015-11-01

    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 (PSLs) 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 nonabsorbing compounds, dusts, soot, and black and brown carbon analogs. SpEx measurements are expected to help identify the presence of ambient brown carbon due to its 300 nm lower wavelength limit compared to measurements limited to longer UV and visible wavelengths. Extinction spectra obtained with SpEx contain more information than can be conveyed by a simple power law fit (typically represented by Ångström exponents). Planned future improvements aim to lower detection limits and ruggedize the instrument for mobile operation.

  6. Aerosol extinction models based on measurements at two sites in Sweden.

    PubMed

    Kaurila, Timo; Hågård, Arne; Persson, Rolf

    2006-09-10

    Two aerosol extinction models have been developed using statistical analysis of long-term optical transmission measurements in Sweden performed at two locations from July 1977 to June 1982. The aerosol volume extinction coefficient for infrared (IR) radiation is calculated by the models with visibility, temperature, and air pressure as input parameters. As in the MODTRAN model, the IR extinction coefficient is proportional to the coefficient at 550 nm, which depends on the visibility. In the new models, the wavelength dependence of the extinction also depends on the visibility. The models predict significantly higher attenuation in the IR than does the Rural aerosol model from MODTRAN, which is commonly used. Comparison with the Maritime model shows that the new models predict lower extinction values in the 3-5 microm region and higher values in the 8-12 microm region. The uncertainties in terms of variance levels are calculated by the models. The properties of aerosols, and thereby the extinction coefficient, are partly correlated to local meteorological parameters, which enables the calculation of a mean predicted value. A substantial part of the variation is, however, caused by conditions in the source area and along the trajectory path of the aerosols. They are not correlated to the local meteorological parameters and therefore cause the variance in the models. PMID:16926909

  7. Aerosol and ozone radiative forcing 1990-2015

    NASA Astrophysics Data System (ADS)

    Myhre, Cathrine Lund; Myhre, Gunnar; Samset, Bjørn H.; Schulz, Michael

    2016-04-01

    The regional changes in economic growth and pollution regulations have caused large changes in the geographical distribution of emissions of precursors and components affecting the radiation balance. Here we use recently updated emission data over the 1990-2015 period in eight global aerosol models to simulate aerosol and ozone changes and their radiative forcing. The models reproduce the general large-scale changes in aerosol and ozone changes over this period. The surface particle mass changes is simulated to 2-3 %/yr for the total fine particle concentration over main industrialized regions. Six models simulated changes in PM2.5 (particulate matter with aerodynamic diameters less 2.5 μm) over the 1990-2015 period. Observations of changes in PM2.5 are available for selected regions and time periods. The available PM2.5 trends from observations and model mean results are compared and for Europe the observed trend is 20% stronger than the model-mean over the 2000-2010 period. Over the 1990-2010 period the US observed changes are 13% lower than the simulated changes. Despite this relatively promising result, the agreement over US for the 2000-2010 period is poor. The reasons for this will be further explored. The forcing for ozone and aerosols increase over the 1990-2015 period and more positive relative to results in IPCC AR5. The main reason for a positive aerosol forcing over this period is explained by a substantial reduction of global mean SO2 emissions, in parallel with increasing black carbon emissions.

  8. The Odin-OSIRIS Data Sets - Twelve Years of Ozone, Bromine Monoxide, Nitrogen Dioxide and Stratospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Lloyd, N. D.; Bourassa, A. E.; Degenstein, D. A.; McLinden, C. A.

    2013-12-01

    The Canadian built OSIRIS instrument has just finished its twelfth full year of operation on-board the Swedish led spacecraft Odin. During these twelve years OSIRIS has measured the limb radiance profile of spectrally dispersed scattered sunlight in the wavelength range from 280 nm to 810 nm with approximately 1 nm spectral resolution. These measurements have been used to retrieve vertical number density profiles of ozone, nitrogen dioxide and bromine monoxide as well as vertical profiles of the stratospheric aerosol extinction at 750 nm. The OSIRIS data sets have been extensively used for process studies and have been included in many international initiatives including the SPARC DI, SPIN, the ozone_cci, the aerosol_cci and the SI2N. This paper details the data products and their availability as well as presenting OSIRIS related scientific highlights and contributions to the above mentioned initiatives

  9. Retrieval of aerosol backscatter and extinction from airborne coherent Doppler wind lidar measurements

    NASA Astrophysics Data System (ADS)

    Chouza, F.; Reitebuch, O.; Groß, S.; Rahm, S.; Freudenthaler, V.; Toledano, C.; Weinzierl, B.

    2015-07-01

    A novel method for calibration and quantitative aerosol optical property retrieval from Doppler wind lidars (DWLs) is presented in this work. Due to the strong wavelength dependence of the atmospheric molecular backscatter and the low sensitivity of the coherent DWLs to spectrally broad signals, calibration methods for aerosol lidars cannot be applied to coherent DWLs usually operating at wavelengths between 1.5 and 2 μm. Instead, concurrent measurements of an airborne DWL at 2 μm and the POLIS ground-based aerosol lidar at 532 nm are used in this work, in combination with sun photometer measurements, for the calibration and retrieval of aerosol backscatter and extinction profiles at 532 nm. The proposed method was applied to measurements from the SALTRACE experiment in June-July 2013, which aimed at quantifying the aerosol transport and change in aerosol properties from the Sahara desert to the Caribbean. The retrieved backscatter and extinction coefficient profiles from the airborne DWL are within 20 % of POLIS aerosol lidar and CALIPSO satellite measurements. Thus the proposed method extends the capabilities of coherent DWLs to measure profiles of the horizontal and vertical wind towards aerosol backscatter and extinction profiles, which is of high benefit for aerosol transport studies.

  10. Spectral Aerosol Extinction (SpEx): A New Instrument for In situ Ambient Aerosol Extinction Measurements Across the UV/Visible Wavelength Range

    NASA Technical Reports Server (NTRS)

    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.; Thornhill, K. L.; Troop, D.; Winstead, Edward L.; Ziemba, L. D.

    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.

  11. Tropospheric ozone and aerosol distributions across the Amazon Basin

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Gregory, G. L.; Harriss, R. C.; Kirchhoff, V. W. J. H.

    1988-01-01

    As a part of the NASA Global Tropospheric Experiment to study the Amazon boundary layer, ozone and aerosol distributions were made measured in July-August 1985 by a NASA Electra aircraft on several long-range flights spanning different areas between Tabatinga and Belem, Brazil. Both positive and negative correlations were found in PBL between aerosol concentrations and O3 mixing ratios. The negative correlations result from the downward transport of relatively clean O3-rich air from the upper troposphere into PBL (which normally has higher aerosol loading and lower O3 concentrations than troposphere); positive correlations are found in biomass-burning plumes, where the aerosols are emitted into the air and O3 is photochemically produced. It was found that, in the dry season, a significant portion of the ozone over the rain forest is a result of biomass burning and that the distribution of photochemically produced O3 is strongly affected by synoptic-scale transport from large fires to the south/southeast.

  12. Polar stratospheric clouds in the 1998-2003 Antarctic vortex: Microphysical modeling and Polar Ozone and Aerosol Measurement (POAM) III observations

    NASA Astrophysics Data System (ADS)

    Benson, C. M.; Drdla, K.; Nedoluha, G. E.; Shettle, E. P.; Alfred, J.; Hoppel, K. W.

    2006-09-01

    The Integrated Microphysics and Aerosol Chemistry on Trajectories (IMPACT) model is used to study polar stratospheric cloud (PSC) formation and evolution in the Antarctic vortex. The model is applied to individual air parcel trajectories driven by UK Met Office (UKMO) wind and temperature fields. The IMPACT model calculates the parcel microphysics, including the formation and sedimentation of ice, nitric acid trihydrate (NAT), sulfuric acid tetrahydrate (SAT), and supercooled ternary solution (STS) aerosols. Model results are validated by comparison with data obtained by the Polar Ozone and Aerosol Measurement (POAM) III solar occultation instrument and are examined for 6 years of POAM data (1998-2003). Comparisons of POAM water vapor and aerosol extinction measurements to the model results help to constrain three microphysical parameters influencing the formation and growth of both type I and type II PSCs. Principally, measurements of aerosol extinction prove to be valuable in differentiating model runs; the relationship of aerosol extinction to temperature is determined by the various particle types as they form and grow. Comparison of IMPACT calculations of this relationship to POAM measurements suggests that the initial fraction of nuclei available for heterogeneous NAT freezing is approximately 0.02% of all aerosols. Constraints are also placed on the accommodation coefficient of ice and the NAT-ice lattice compatibility. However, these two parameters have similar effects on the extinction-temperature relationship, and thus a range of values are permissible for each.

  13. Visible and infrared extinction of atmospheric aerosol in the marine and coastal environment.

    PubMed

    Kaloshin, Gennady A

    2011-05-10

    The microphysical model Marine Aerosol Extinction Profiles (MaexPro) for surface layer marine and coastal atmospheric aerosols, which is based on long-term observations of size distributions for 0.01-100 μm particles, is presented. The fundamental feature of the model is a parameterization of amplitudes and widths for aerosol modes of the aerosol size distribution function (ASDF) as functions of fetch and wind speed. The shape of the ASDF and its dependence on meteorological parameters, altitudes above the sea level (H), fetch (X), wind speed (U), and relative humidity is investigated. The model is primarily to characterize aerosols for the near-surface layer (within 25 m). The model is also applicable to higher altitudes within the atmospheric boundary layer, where the change in the vertical profile of aerosol is not very large. In this case, it is only valid for "clean" marine environments, in the absence of air pollution or any other major sources of continental aerosols, such desert dust or smoke from biomass burning. The spectral profiles of the aerosol extinction coefficients calculated by MaexPro are in good agreement with observational data and the numerical results obtained by the well-known Navy Aerosol Model and Advanced Navy Aerosol Model codes. Moreover, MaexPro was found to be an accurate and reliable instrument for investigation of the optical properties of atmospheric aerosols. PMID:21556113

  14. Spectral dependence on the correction factor of erythemal UV for cloud, aerosol, total ozone, and surface properties: A modeling study

    NASA Astrophysics Data System (ADS)

    Park, Sang Seo; Jung, Yeonjin; Lee, Yun Gon

    2016-07-01

    Radiative transfer model simulations were used to investigate the erythemal ultraviolet (EUV) correction factors by separating the UV-A and UV-B spectral ranges. The correction factor was defined as the ratio of EUV caused by changing the amounts and characteristics of the extinction and scattering materials. The EUV correction factors (CFEUV) for UV-A [CFEUV(A)] and UV-B [CFEUV(B)] were affected by changes in the total ozone, optical depths of aerosol and cloud, and the solar zenith angle. The differences between CFEUV(A) and CFEUV(B) were also estimated as a function of solar zenith angle, the optical depths of aerosol and cloud, and total ozone. The differences between CFEUV(A) and CFEUV(B) ranged from -5.0% to 25.0% for aerosols, and from -9.5% to 2.0% for clouds in all simulations for different solar zenith angles and optical depths of aerosol and cloud. The rate of decline of CFEUV per unit optical depth between UV-A and UV-B differed by up to 20% for the same aerosol and cloud conditions. For total ozone, the variation in CFEUV(A) was negligible compared with that in CFEUV(B) because of the effective spectral range of the ozone absorption band. In addition, the sensitivity of the CFEUVs due to changes in surface conditions (i.e., surface albedo and surface altitude) was also estimated by using the model in this study. For changes in surface albedo, the sensitivity of the CFEUVs was 2.9%-4.1% per 0.1 albedo change, depending on the amount of aerosols or clouds. For changes in surface altitude, the sensitivity of CFEUV(B) was twice that of CFEUV(A), because the Rayleigh optical depth increased significantly at shorter wavelengths.

  15. Measuring Aerosol Optical Properties with the Ozone Monitoring Instrument (OMI)

    NASA Technical Reports Server (NTRS)

    Veefkind, J. P.; Torres, O.; Syniuk, A.; Decae, R.; deLeeuw, G.

    2003-01-01

    The Ozone Monitoring Instrument (OMI) is the Dutch-Finnish contribution to the NASA EOS-Aura mission scheduled for launch in January 2004. OM1 is an imaging spectrometer that will measure the back-scattered Solar radiance between 270 an 500 nm. With its relatively high spatial resolution (13x24 sq km at nadir) and daily global coverage. OM1 will make a major contribution to our understanding of atmospheric chemistry and to climate research. OM1 will provide data continuity with the TOMS instruments. One of the pleasant surprises of the TOMS data record was its information on aerosol properties. First, only the absorbing aerosol index, which is sensitive to elevated lay- ers of aerosols such as desert dust and smoke aerosols, was derived. Recently these methods were further improved to yield aerosol optical thickness and single scattering albedo over land and ocean for 19 years of TOMS data (1979-1992,1997-2002), making it one of the longest and most valuable time series for aerosols presently available. Such long time series are essential to quantify the effect of aerosols on the Earth& climate. The OM1 instrument is better suited to measure aerosols than the TOMS instruments because of the smaller footprint, and better spectral coverage. The better capabilities of OMI will enable us to provide an improved aerosol product, but the knowledge will also be used for further analysis of the aerosol record from TOMS. The OM1 aerosol product that is currently being developed for OM1 combines the TOMS experience and the multi-spectral techniques that are used in the visible and near infrared. The challenge for this new product is to provide aerosol optical thickness and single scattering albedo from the near ultraviolet to the visible (330-500 nm) over land and ocean. In this presentation the methods for deriving the OM1 aerosol product will be presented. Part of these methods developed for OM1 can already be applied to TOMS data and results of such analysis will be shown.

  16. Using Airborne High Spectral Resolution Lidar Data to Evaluate Combined Active Plus Passive Retrievals of Aerosol Extinction Profiles

    NASA Technical Reports Server (NTRS)

    Burton, S. P.; Ferrare, R. A.; Kittaka, C.; Hostetler, C. A.; Hair, J. W.; Obland, M. D.; Rogers, R. R.; Cook, A. L.; Haper, D. B.

    2008-01-01

    Aerosol extinction profiles are derived from backscatter data by constraining the retrieval with column aerosol optical thickness (AOT), for example from coincident MODIS observations and without reliance on a priori assumptions about aerosol type or optical properties. The backscatter data were acquired with the NASA Langley High Spectral Resolution Lidar (HSRL). The HSRL also simultaneously measures extinction independently, thereby providing an ideal data set for evaluating the constrained retrieval of extinction from backscatter. We will show constrained extinction retrievals using various sources of column AOT, and examine comparisons with the HSRL extinction measurements and with a similar retrieval using data from the CALIOP lidar on the CALIPSO satellite.

  17. An Investigation of Aerosol and Ozone Measurements from the Cryogenic Limb Array Etalon Spectrometer: Validation and Relation to Other Chemical Species

    NASA Technical Reports Server (NTRS)

    Deshler, Terry

    1997-01-01

    Throughout this study we focused on comparisons of CLAES and in situ measurements of ozone and aerosol extinction. Thus the comparison is between satellite data representative of large spatial regions and in situ data representative of nearly point samples. Both instruments provide vertical profiles, but the region of overlap is limited to between approximately 10 and 100 mb. CLAES Version 7 ozone measurements have been compared to electrochemical cell ozonesonde measurements over McMurdo Station, Antarctica (78 deg S, 167 deg E), Dumont d'Urville, Antarctica (66.7 deg S, 140 deg E), Laramie, Wyoming (41 deg N, 106 deg W), and Bear Island, Norway (74.3 deg N, 19 deg E). Comparisons were made between vertical ozone profiles, and between integrated column ozone over the region of overlap of the measurements. Comparisons using CLAES Version 8 data are underway. CLAES Version 8 aerosol extinction measurements at all wavelengths have also been compared to University of Wyoming aerosol extinctions over McMurdo Station, Antarctica, and over Laramie, Wyoming. Coincidences in all cases were determined by minimizing the distance between the CLAES observations and the surface station, and the time separation between the satellite and in situ measurements.

  18. SAGE I and SAM II measurements of 1 micron aerosol extinction in the free troposphere

    NASA Technical Reports Server (NTRS)

    Kent, G. S.; Farrukh, U. O.; Wang, P. H.; Deepak, A.

    1988-01-01

    The SAGE-I and SAM-II satellite sensors were designed to measure, with global coverage, the 1 micron extinction produced by the stratospheric aerosol. In the absence of high altitude clouds, similar measurements may be made for the free tropospheric aerosol. Median extinction values at middle and high latitudes in the Northern Hemisphere, for altitudes between 5 and 10 km, are found to be one-half to one order of magnitude greater than values at corresponding latitudes in the Southern Hemisphere. In addition, a seasonal increase by a factor of 1.5-2 was observed in both hemispheres, in 1979-80, in local spring and summer. Following major volcanic eruptions, a long-lived enhancement of the aerosol extinction is observed for altitudes above 5 km.

  19. Feasibility Study For A Spaceborne Ozone/Aerosol Lidar System

    NASA Technical Reports Server (NTRS)

    Campbell, Richard E.; Browell, Edward V.; Ismail, Syed; Dudelzak, Alexander E.; Carswell, Allan I.; Ulitsky, Arkady

    1997-01-01

    Because ozone provides a shield against harmful ultraviolet radiation, determines the temperature profile in the stratosphere, plays important roles in tropospheric chemistry and climate, and is a health risk near the surface, changes in natural ozone layers at different altitudes and their global impact are being intensively researched. Global ozone coverage is currently provided by passive optical and microwave satellite sensors that cannot deliver high spatial resolution measurements and have particular limitations in the troposphere. Vertical profiling DIfferential Absorption Lidars (DIAL) have shown excellent range-resolved capabilities, but these systems have been large, inefficient, and have required continuous technical attention for long term operations. Recently, successful, autonomous DIAL measurements have been performed from a high-altitude aircraft (LASE - Lidar Atmospheric Sensing Experiment), and a space-qualified aerosol lidar system (LITE - Laser In-space Technology Experiment) has performed well on Shuttle. Based on the above successes, NASA and the Canadian Space Agency are jointly studying the feasibility of developing ORACLE (Ozone Research with Advanced Cooperative Lidar Experiments), an autonomously operated, compact DIAL instrument to be placed in orbit using a Pegasus class launch vehicle.

  20. Validation of GOMOS-Envisat vertical profiles of O3, NO2, NO3, and aerosol extinction using balloon-borne instruments and analysis of the retrievals

    NASA Astrophysics Data System (ADS)

    Renard, Jean-Baptiste; Berthet, Gwenaël; Brogniez, Colette; Catoire, Valery; Fussen, Didier; Goutail, Florence; Oelhaf, Hermann; Pommereau, Jean-Pierre; Roscoe, Howard K.; Wetzel, Gerald; Chartier, Michel; Robert, Claude; Balois, Jean-Yves; Verwaerde, Christian; Auriol, Frédérique; François, Philippe; Gaubicher, Bertrand; Wursteisen, Patrick

    2008-02-01

    The UV-visible Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument onboard Envisat performs nighttime measurements of ozone, NO2, NO3 and of the aerosol extinction, using the stellar occultation method. We have conducted a validation exercise using various balloon-borne instruments in different geophysical conditions from 2002 to 2006, using GOMOS measurements performed with stars of different magnitudes. GOMOS and balloon-borne vertical columns in the middle stratosphere are in excellent agreement for ozone and NO2. Some discrepancies can appear between GOMOS and balloon-borne vertical profiles for the altitude and the amplitude of the concentration maximum. These discrepancies are randomly distributed, and no bias is detected. The accuracy of individual profiles in the middle stratosphere is 10 % for ozone and 25 % for NO2. On the other hand, the GOMOS NO3 retrieval is difficult and no direct validation can be conducted. The GOMOS aerosol content is also well estimated, but the wavelength dependence can be better estimated if the aerosol retrieval is performed only in the visible domain. We can conclude that the GOMOS operational retrieval algorithm works well and that GOMOS has fully respected its primary objective for the study of the trends of species in the middle stratosphere, using the profiles in a statistical manner. Some individual profiles can be partly inaccurate, in particular in the lower stratosphere. Improvements could be obtained by reprocessing some GOMOS transmissions in case of specific studies in the middle and lower stratosphere when using the individual profiles.

  1. The Ny-Alesund aerosol and ozone measurements intercomparison campaign 1997/1998 (NAOMI-1998)

    NASA Technical Reports Server (NTRS)

    Neuber, R.; Beyerle, G.; Beninga, I.; VonderGathen, P.; Rairoux, P.; Schrems, O.; Wahl, P.; Gross, M.; McGee, Th.; Iwasaka, Y.; Fujiwara, M.; Shibata, T.; Klein, U.; Steinbrecht, W.

    1998-01-01

    An intercomparison campaign for Lidar measurements of stratospheric ozone and aerosol has been conducted at the Primary Station of the Network for the Detection of Stratospheric Change (NDSC) in Ny-Alesund/Spitsbergen during January-February 1998. In addition to local instrumentation, the NDSC mobile ozone lidar from NASA/GSFC and the mobile aerosol lidar from Alfred Wegener Institute (AWI) participated. The aim is the validation of stratospheric ozone and aerosol profile measurements according to NDSC guidelines. This paper briefly presents the employed instruments and outlines the campaign. Results of the blind intercomparison of ozone profiles are given in a companion paper and temperature measurements are described in this issue.

  2. Enhanced extinction of visible radiation due to hydrated aerosols in mist and fog

    NASA Astrophysics Data System (ADS)

    Elias, T.; Dupont, J.-C.; Hammer, E.; Hoyle, C. R.; Haeffelin, M.; Burnet, F.; Jolivet, D.

    2015-06-01

    The study assesses the contribution of aerosols to the extinction of visible radiation in the mist-fog-mist cycle. Relative humidity is large in the mist-fog-mist cycle, and aerosols most efficient in interacting with visible radiation are hydrated and compose the accumulation mode. Measurements of the microphysical and optical properties of these hydrated aerosols with diameters larger than 0.4 μm were carried out near Paris, during November 2011, under ambient conditions. Eleven mist-fog-mist cycles were observed, with a cumulated fog duration of 96 h, and a cumulated mist-fog-mist cycle duration of 240 h. In mist, aerosols grew by taking up water at relative humidities larger than 93%, causing a visibility decrease below 5 km. While visibility decreased down from 5 to a few kilometres, the mean size of the hydrated aerosols increased, and their number concentration (Nha) increased from approximately 160 to approximately 600 cm-3. When fog formed, droplets became the strongest contributors to visible radiation extinction, and liquid water content (LWC) increased beyond 7 mg m-3. Hydrated aerosols of the accumulation mode co-existed with droplets, as interstitial non-activated aerosols. Their size continued to increase, and some aerosols achieved diameters larger than 2.5 μm. The mean transition diameter between the aerosol accumulation mode and the small droplet mode was 4.0 ± 1.1 μm. Nha also increased on average by 60 % after fog formation. Consequently, the mean contribution to extinction in fog was 20 ± 15% from hydrated aerosols smaller than 2.5 μm and 6 ± 7% from larger aerosols. The standard deviation was large because of the large variability of Nha in fog, which could be smaller than in mist or 3 times larger. The particle extinction coefficient in fog can be computed as the sum of a droplet component and an aerosol component, which can be approximated by 3.5 Nha (Nha in cm-3 and particle extinction coefficient in Mm-1. We observed an influence of

  3. A compact mobile ozone lidar for atmospheric ozone and aerosol profiling

    NASA Astrophysics Data System (ADS)

    De Young, Russell; Carrion, William; Pliutau, Denis

    2014-10-01

    A compact mobile differential absorption lidar (DIAL) system has been developed at NASA Langley Research Center to provide ozone, aerosol and cloud atmospheric measurements in a mobile trailer for ground-based atmospheric ozone air quality campaigns. This lidar is integrated into the Tropospheric Ozone Lidar Network (TOLNet) currently made up of four other ozone lidars across the country. The lidar system consists of a UV and green laser transmitter, a telescope and an optical signal receiver with associated Licel photon counting and analog channels. The laser transmitter consists of a Q-switched Nd:YLF inter-cavity doubled laser pumping a Ce:LiCAF tunable UV laser with all the associated power and lidar control support units on a single system rack. The system has been configured to enable mobile operation from a trailer and was deployed to Denver, CO July 15-August 15, 2014 supporting the DISCOVER-AQ campaign. Ozone curtain plots and the resulting science are presented.

  4. A Compact Mobile Ozone Lidar for Atmospheric Ozone and Aerosol Profiling

    NASA Technical Reports Server (NTRS)

    De Young, Russell; Carrion, William; Pliutau, Denis

    2014-01-01

    A compact mobile differential absorption lidar (DIAL) system has been developed at NASA Langley Research Center to provide ozone, aerosol and cloud atmospheric measurements in a mobile trailer for ground-based atmospheric ozone air quality campaigns. This lidar is integrated into the Tropospheric Ozone Lidar Network (TOLNet) currently made up of four other ozone lidars across the country. The lidar system consists of a UV and green laser transmitter, a telescope and an optical signal receiver with associated Licel photon counting and analog channels. The laser transmitter consist of a Q-switched Nd:YLF inter-cavity doubled laser pumping a Ce:LiCAF tunable UV laser with all the associated power and lidar control support units on a single system rack. The system has been configured to enable mobile operation from a trailer and was deployed to Denver, CO July 15-August 15, 2014 supporting the DISCOVER-AQ campaign. Ozone curtain plots and the resulting science are presented.

  5. Combined Dial Sounding of Ozone, Water Vapour and Aerosol

    NASA Astrophysics Data System (ADS)

    Trickl, Thomas; Vogelmann, Hannes

    2016-06-01

    Routine high-quality lidar measurements of ozone, water vapour and aerosol at Garmisch-Partenkirchen since 2007 have made possible more comprehensive atmospheric studies and lead to a growing insight concerning the most frequently occurring long-range transport pathways. In this contribution we present as examples results on stratospheric layers travelling in the free troposphere for extended periods of time without eroding. In particular, we present a case of an intrusion layer that subsided over as many as fifteen days and survived the interference by strong Canadian fires. These results impose a challenge on atmospheric modelling that grossly overestimates free-tropospheric mixing.

  6. Airborne lidar measurements of ozone and aerosols during the pacific exploratory mission-tropics A

    NASA Technical Reports Server (NTRS)

    Fenn, Marta A.; Browell, Edward V.; Grant, William B.; Butler, Carolyn F.; Kooi, Susan A.; Clayton, Marian B.; Brackett, Vincent G.; Gregory, Gerald L.

    1998-01-01

    Airborne lidar measurements of aerosol and ozone distributions from the surface to above the tropopause over the South Pacific Ocean are presented. The measurements illustrate large-scale features of the region, and are used to quantify the relative contributions of different ozone sources to the tropospheric ozone budget in this remote region.

  7. Improved stratospheric aerosol extinction profiles from SCIAMACHY: validation and sample results

    NASA Astrophysics Data System (ADS)

    von Savigny, C.; Ernst, F.; Rozanov, A.; Hommel, R.; Eichmann, K.-U.; Rozanov, V.; Burrows, J. P.; Thomason, L. W.

    2015-12-01

    Stratospheric aerosol extinction profiles have been retrieved from SCIAMACHY/Envisat measurements of limb-scattered solar radiation. The retrieval is an improved version of an algorithm presented earlier. The retrieved aerosol extinction profiles are compared to co-located aerosol profile measurements from the SAGE II solar occultation instrument at a wavelength of 525 nm. Comparisons were carried out with two versions of the SAGE II data set (version 6.2 and the new version 7.0). In a global average sense the SCIAMACHY and the SAGE II version 7.0 extinction profiles agree to within about 10 % for altitudes above 15 km. Larger relative differences (up to 40 %) are observed at specific latitudes and altitudes. We also find differences between the two SAGE II data versions of up to 40 % for specific latitudes and altitudes, consistent with earlier reports. Sample results on the latitudinal and temporal variability of stratospheric aerosol extinction and optical depth during the SCIAMACHY mission period are presented. The results confirm earlier reports that a series of volcanic eruptions is responsible for the increase in stratospheric aerosol optical depth from 2002 to 2012. Above about an altitude of 28 km, volcanic eruptions are found to have negligible impact in the period 2002-2012.

  8. Improved stratospheric aerosol extinction profiles from SCIAMACHY: validation and sample results

    NASA Astrophysics Data System (ADS)

    von Savigny, C.; Ernst, F.; Rozanov, A.; Hommel, R.; Eichmann, K.-U.; Rozanov, V.; Burrows, J. P.; Thomason, L. W.

    2015-08-01

    Stratospheric aerosol extinction profiles have been retrieved from SCIAMACHY/Envisat measurements of limb-scattered solar radiation. The retrieval is an improved version of an algorithm presented earlier. The retrieved aerosol extinction profiles are compared to co-located aerosol profile measurements with the SAGE II solar occultation instrument at a wavelength of 525 nm. Comparisons were carried out with two versions of the SAGE II data set (version 6.2 and the new version 7.0). In a global average sense the SCIAMACHY and the SAGE II version 7.0 extinction profiles agree to within about 10 % for altitudes above 15 km. Larger relative differences (up to 40 %) are observed at specific latitudes and altitudes. We also find differences between the two SAGE II data versions of up to 40 % for specific latitudes and altitudes. Sample results on the latitudinal and temporal variability of stratospheric aerosol extinction and optical depth during the SCIAMACHY mission period are presented. The results indicate that a series of volcanic eruptions is responsible for the increase in stratospheric aerosol optical depth from 2002 to 2012. Above about 28 km altitude volcanic eruptions are found to have negligible impact in the period 2002 to 2012.

  9. Observations of Ozone-aerosol Correlated Behaviour in the Lower Stratosphere During the EASOE Campaign

    NASA Technical Reports Server (NTRS)

    Digirolamo, P.; Cacciani, M.; Disarra, A.; Fiocco, G.; Fua, D.; Joergensen, T. S.; Knudsen, B.; Larsen, N.

    1992-01-01

    The question of possible interactions between ozone and stratospheric aerosol has been open for a long time. Measurements carried out after the Mt. Agung and El Chicon eruptions showed evidence of negative correlations between the presence of volcanic stratospheric aerosols and ozone concentration. Evidence for negative correlations in the polar winter has been also found. It is only after the discovery of the Antarctic ozone hole that catalytic effects related to low temperature heterogeneous chemistry have become the object of much investigation, now extended to the role of volcanic aerosol in the ozone reduction. These phenomena can be the object of various interpretations, not mutually exclusive, including the effect of transport, diffuse radiation as well as heterogeneous chemistry. The present paper provides preliminary results of simultaneous measurements of ozone and aerosol, carried out at Thule, Greenland, during the winter 1991-92. The European Stratospheric Ozone Experiment (EASOE) was aimed at monitoring the winter Arctic stratosphere in order to obtain a deeper insight of the ozone destruction processes taking place in the polar regions. A large amount of aerosol was injected into the lower stratosphere by the recent eruption of Volcano Pinatubo. A lidar system, already operational in Thule since November 1990, has provided detailed measurements of the stratospheric aerosol concentration during EASOE. In the same period, a large number of ozonesondes were launched. Although no PSC formation was detected over Thule, the simultaneous measurement of the stratospheric aerosol and ozone profiles give the possibility to study interactions occurring in the stratosphere between these two constituents.

  10. Enhanced extinction of visible radiation due to hydrated aerosols in mist and fog

    NASA Astrophysics Data System (ADS)

    Elias, T.; Dupont, J.-C.; Hammer, E.; Hoyle, C. R.; Haeffelin, M.; Burnet, F.; Jolivet, D.

    2015-01-01

    The study assesses the contribution of aerosols to the extinction of visible radiation in the mist-fog-mist cycle. Measurements of the microphysical and optical properties of hydrated aerosols with diameters larger than 400 nm, composing the accumulation mode, which are the most efficient to interact with visible radiation, were carried out near Paris, during November 2011, in ambient conditions. Eleven mist-fog-mist cycles were observed, with cumulated fog duration of 95 h, and cumulated mist-fog-mist duration of 240 h. In mist, aerosols grew up by taking up water at relative humidities larger than 93%, causing a visibility decrease below 5 km. While visibility decreased down to few km, the mean size of the hydrated aerosols increased, and their number concentration (Nha) increased from approximately 160 to approximately 600 cm-3. When fog formed, droplets became the strongest contributors to visible radiation extinction, and liquid water content (LWC) increased beyond 7 mg m-3. Hydrated aerosols of the accumulation mode co-existed with droplets, as interstitial non-activated aerosols. Their size continued to increase, and a significant proportion of aerosols achieved diameters larger than 2.5 μm. The mean transition diameter between the accumulation mode and the small droplet mode was 4.0 ± 1.1 μm. Moreover Nha increased on average by 60% after fog formation. Consequently the mean aerosol contribution to extinction in fog was 20 ± 15% for diameter smaller than 2.5 μm and 6 ± 7% beyond. The standard deviation is large because of the large variability of Nha in fog, which could be smaller than in mist or three times larger. The particle extinction coefficient in fog can be computed as the sum of a droplet component and an aerosol component, which can be approximated by 3.5 Nha (Nha in cm-3 and particle extinction coefficient in Mm-1). We observed an influence of the main formation process on Nha, but not on the contribution to fog extinction by aerosols

  11. The Application of TOMS Ozone, Aerosol and UV-B Data to Madagascar Air Quality Determination

    NASA Technical Reports Server (NTRS)

    Aikin, A.C.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Total Ozone Mapping Spectrometer (TOMS) data products for the area of Madagascar are presented. In addition to total ozone, aerosols and UV-B tropospheric ozone results are shown from 1979 to the present. Tropospheric ozone over Africa and Madagascar is enhanced by 10 to 15 DU in October. This maximum coincides with the time of maximum biomass area burning in Africa and Madagascar. Ozone observations were made from 1979 to 1999 using the TOMS tropospheric ozone convective cloud differential method. As a result of easterly trade winds, ozone originating on Madagascar is transported to the west over the Mozambique Channel. In El Nino years higher level westerly winds descend to transport low level ozone easterly. This results in African continental ozone being transported east of Madagascar. Long range transport of African ozone is observed during El Nino periods. The potential of TOMS and other space data for use in public education and research on Madagascar air quality is demonstrated.

  12. AROTEL - An Airborne Ozone, Aerosol and Temperature Lidar

    NASA Technical Reports Server (NTRS)

    McGee, Thomas J.; Burris, John F.; Hoegy, Walter; Heaps, William; Silbert, Donald; Twigg, Laurence; Sumnicht, Grant; Nueber, Roland; Schmidt, Thomas; Hostetler, Chris

    2000-01-01

    The AROTEL instrument is a collaboration between scientists at NASA, Goddard Space Flight Center and NASA Langley Research Center. The instrument was designed and constructed to be flown on the NASA DC-8, and to measure vertical profiles of ozone, temperature and aerosol. The instrument transmits radiation at 308, 355, 532, and 1064 nm. Depolarization is measured at 532 nm. In addition to the transmitted wavelengths, Raman scattered signals at 332 nm and 387 nm are also collected. The instrument was installed aboard the DC-8 for the SAGE III Ozone Loss and Validation Experiment (SOLVE) which deployed from Kiruna, Sweden, during the winter of 1999-2000 to study the polar stratosphere. During this time, profile measurements of polar stratospheric clouds, ozone and temperature were made. This paper provides an instrumental overview as an introduction to several data papers to be presented in the poster sessions. In addition to samples of the measurements, examples will be given to establish the quality of the various data products.

  13. Light extinction by aerosols during summer air pollution

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

    In order to utilize satellite measurements of optical thickness over land for estimating aerosol properties during air pollution episodes, the optical thickness was measured from the surface and investigated. Aerosol optical thicknesses have been derived from solar transmission measurements in eight spectral bands within the band lambda 440-870 nm during the summers of 1980 and 1981 near Washington, DC. The optical thicknesses for the eight bands are strongly correlated. It was found that first eigenvalue of the covariance matrix of all observations accounts for 99 percent of the trace of the matrix. Since the measured aerosol optical thickness was closely proportional to the wavelength raised to a power, the aerosol size distribution derived from it is proportional to the diameter (d) raised to a power for the range of diameters between 0.1 to 1.0 micron. This power is insensitive to the total optical thickness. Changes in the aerosol optical thickness depend on several aerosol parameters, but it is difficult to identify the dominant one. The effects of relative humidity and accumulation mode concentration on the optical thickness are analyzed theoretically, and compared with the measurements.

  14. OZONE-ISOPRENE REACTION: RE-EXAMINATION OF THE FORMATION OF SECONDARY ORGANIC AEROSOL

    EPA Science Inventory

    The reaction of ozone and isoprene has been studied to examine physical and chemical characteristics of the secondary organic aerosol formed. Using a scanning mobility particle sizer, the volume distribution of the aerosol was found in the range 0.05 - 0.2 µm. The aerosol yield w...

  15. Simultaneous measurement of optical scattering and extinction on dispersed aerosol samples.

    PubMed

    Dial, Kathy D; Hiemstra, Scott; Thompson, Jonathan E

    2010-10-01

    Accurate and precise measurements of light scattering and extinction by atmospheric particulate matter aid understanding of tropospheric photochemistry and are required for estimates of the direct climate effects of aerosols. In this work, we report on a second generation instrument to simultaneously measure light scattering (b(scat)) and extinction (b(ext)) coefficient by dispersed aerosols. The ratio of scattering to extinction is known as the single scatter albedo (SSA); thus, the instrument is referred to as the albedometer. Extinction is measured with the well-established cavity ring-down (CRD) technique, and the scattering coefficient is determined through collection of light scattered from the CRD beam. The improved instrument allows reduction in sample volume to <1% of the original design, and a reduction in response time by a factor of >30. Through using a commercially available condensation particle counter (CPC), we have measured scattering (σ(scat)) and extinction (σ(ext)) cross sections for size-selected ammonium sulfate and nigrosin aerosols. In most cases, the measured scattering and extinction cross section were within 1 standard deviation of the accepted values generated from Mie theory suggesting accurate measurements are made. While measurement standard deviations for b(ext) and b(scat) were generally <1 Mm(-1) when the measurement cell was sealed or purged with filtered air, relative standard deviations >0.1 for these variables were observed when the particle number density was low. It is inferred that statistical fluctuations of the absolute number of particles within the probe beam leads to this effect. However, measured relative precision in albedo is always superior to that which would be mathematically propagated assuming independent measurements of b(scat) and b(ext). Thus, this report characterizes the measurement precision achieved, evaluates the potential for systematic error to be introduced through light absorption by gases

  16. Products of BVOC oxidation: ozone and organic aerosols

    NASA Astrophysics Data System (ADS)

    Wildt, Jürgen; Andres, Stefanie; Carriero, Giulia; Ehn, Mikael; Fares, Silvano; Hoffmann, Thorsten; Hacker, Lina; Kiendler-Scharr, Astrid; Kleist, Einhard; Paoletti, Elena; Pullinen, Iida; Rohrer, Franz; Rudich, Yinon; Springer, Monika; Tillmann, Ralf; Wahner, Andreas; Wu, Cheng; Mentel, Thomas

    2015-04-01

    Biogenic Volatile Organic Compounds (BVOC) are important precursors in photochemical O3 and secondary organic aerosol (SOA) formation. We conducted a series of laboratory experiments with OH-induced oxidation of monoterpenes to elucidate pathways and efficiencies of O3 and SOA formation. At high NOx conditions ([BVOC] / [NOx] < 7 ppbC / ppb) photochemical ozone formation was observed. For -pinene as individual BVOC as well as for the monoterpene mixes emitted from different plant species we observed increasing ozone formation with increasing [NOX]. Between 2 and 3 O3-molecules were formed from 1 monoterpene when ozone formation was BVOC limited. Under such high NOX conditions, new particle formation was suppressed. Increasing [BVOC] / [NOX] ratios caused increasing efficiency of new particle formation indicating that peroxy radicals are the key intermediates in both, photochemical ozone- and new particle formation. The classical chemistry of peroxy radicals is well established (e.g. Master Chemical Mechanism). Peroxy radicals are produced by addition of molecular oxygen to the alkyl radical formed after OH attack at the BVOC. They either react with NO which leads to ozone formation or they react with other peroxy radicals and form chemically stable products (hydroperoxides, alkoholes and ketones). Much less knowledge exists on such reactions for Highly Oxidized Peroxy Radicals, (HOPR). Such HOPR were observed during ozonolysis of several volatiles and, in case of monoterpenes as precursors, they can contain more than 12 Oxygen atoms (Mentel et al., 2015). Although the OH-initiated formation of HOPR is yet not fully understood, their basic gas phase reactions seem to follow classical photochemical rules. In reactions with NO they can act as precursor for O3 and in reactions with other HOPR or with classical less oxidized peroxy radicals they can form highly oxidized stable products and alkoxy radicals. In addition, HOPR-HOPR reactions lead to the formation of

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  18. Radiative properties of the background aerosol: absorption component of extinction.

    PubMed

    Clarke, A D; Charlson, R J

    1985-07-19

    The light-scattering and light-absorption coefficients of the global background aerosol define its single-scatter albedo. Continuous, simultaneous measurements of these optical coefficients were made on a daily basis for the remote marine mid-troposphere; such measurements are essential for assessment of the effects of aerosol on atmospheric radiative transfer. Measurements of light-absorption coefficients made at the Mauna Loa Observatory in Hawaii were higher than expected, and the single-scatter albedo was lower than the value often used in radiative transfer models. Soot appears to be the most likely primary absorber, and hemispheric dispersal of this combustion-derived material is suggested. PMID:17759145

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  20. Selection Algorithm for the CALIPSO Lidar Aerosol Extinction-to-Backscatter Ratio

    NASA Technical Reports Server (NTRS)

    Omar, Ali H.; Winker, David M.; Vaughan, Mark A.

    2006-01-01

    The extinction-to-backscatter ratio (S(sub a)) is an important parameter used in the determination of the aerosol extinction and subsequently the optical depth from lidar backscatter measurements. We outline the algorithm used to determine Sa for the Cloud and Aerosol Lidar and Infrared Pathfinder Spaceborne Observations (CALIPSO) lidar. S(sub a) for the CALIPSO lidar will either be selected from a look-up table or calculated using the lidar measurements depending on the characteristics of aerosol layer. Whenever suitable lofted layers are encountered, S(sub a) is computed directly from the integrated backscatter and transmittance. In all other cases, the CALIPSO observables: the depolarization ratio, delta, the layer integrated attenuated backscatter, beta, and the mean layer total attenuated color ratio, gamma, together with the surface type, are used to aid in aerosol typing. Once the type is identified, a look-up-table developed primarily from worldwide observations, is used to determine the S(sub a) value. The CALIPSO aerosol models include desert dust, biomass burning, background, polluted continental, polluted dust, and marine aerosols.

  1. In situ measurements constraining the role of sulphate aerosols in mid-latitude ozone depletion

    NASA Technical Reports Server (NTRS)

    Fahey, D. W.; Kawa, S. R.; Woodbridge, E. L.; Tin, P.; Wilson, J. C.; Jonsson, H. H.; Dye, J. E.; Baumgardner, D.; Borrmann, S.; Toohey, D. W.

    1993-01-01

    In situ measurements of stratospheric sulphate aerosol, reactive nitrogen and chlorine concentrations at middle latitudes confirm the importance of aerosol surface reactions that convert active nitrogen to a less active, reservoir form. This makes mid-latitude stratospheric ozone less vulnerable to active nitrogen and more vulnerable to chlorine species. The effect of aerosol reactions on active nitrogen depends on gas phase reaction rates, so that increases in aerosol concentration following volcanic eruptions will have only a limited effect on ozone depletion at these latitudes.

  2. Mount St. Helens related aerosol properties from solar extinction measurements

    NASA Technical Reports Server (NTRS)

    Michalsky, J. J.; Kleckner, E. W.; Stokes, G. M.

    1982-01-01

    A network of solar radiometers, operated on the North American Continent for an average of 2 years before the first major eruption of Mount St. Helens, Washington, continues to collect direct solar data through the eruptive phase of this volcano. The radiometers collect spectral data through 12 interference filters spanning the sensitivity of the photodiode used as detector. The data are collected every 5 minutes in seven filters and every 15 minutes in five additional filters. A variant of the classical Langley method has been used to measure the optical depth of the aerosols as a function of wavelength. The network, which is the nearest station, is located some 180 kilometers east of the volcano, well within range of noticeable effects during much of the minor as well as major activity. The wavelength dependence of the aerosol-optical depth before and after the 22 July 1980 major eruption, which was well characterized because of favorable meteorological conditions is discussed.

  3. Using high time resolution aerosol and number size distribution measurements to estimate atmospheric extinction.

    PubMed

    Malm, William C; McMeeking, Gavin R; Kreidenweis, Sonia M; Levin, Ezra; Carrico, Christian M; Day, Derek E; Collett, Jeffrey L; Lee, Taehyoung; Sullivan, Amy P; Raja, Suresh

    2009-09-01

    Rocky Mountain National Park is experiencing reduced visibility and changes in ecosystem function due to increasing levels of oxidized and reduced nitrogen. The Rocky Mountain Atmospheric Nitrogen and Sulfur (RoMANS) study was initiated to better understand the origins of sulfur and nitrogen species as well as the complex chemistry occurring during transport from source to receptor. As part of the study, a monitoring program was initiated for two 1-month time periods--one during the spring and the other during late summer/fall. The monitoring program included intensive high time resolution concentration measurements of aerosol number size distribution, inorganic anions, and cations, and 24-hr time resolution of PM2.5 and PM10 mass, sulfate, nitrate, carbon, and soil-related elements concentrations. These data are combined to estimate high time resolution concentrations of PM2.5 and PM10 aerosol mass and fine mass species estimates of ammoniated sulfate, nitrate, and organic and elemental carbon. Hour-by-hour extinction budgets are calculated by using these species concentration estimates and measurements of size distribution and assuming internal and external particle mixtures. Summer extinction was on average about 3 times higher than spring extinction. During spring months, sulfates, nitrates, carbon mass, and PM10 - PM2.5 mass contributed approximately equal amounts of extinction, whereas during the summer months, carbonaceous material extinction was 2-3 times higher than other species. PMID:19785272

  4. Measurement of wavelength-dependent extinction to distinguish between absorbing and nonabsorbing aerosol particulates

    NASA Technical Reports Server (NTRS)

    Portscht, R.

    1977-01-01

    Measurements of spectral transmission factors in smoky optical transmission paths reveal a difference between wavelength exponents of the extinction cross section of high absorption capacity and those of low absorption capacity. A theoretical explanation of this behavior is presented. In certain cases, it is possible to obtain data on the absorption index of aerosol particles in the optical path by measuring the spectral decadic extinction coefficient at, at least, two wavelengths. In this manner it is possible, for instance, to distinguish smoke containing soot from water vapor.

  5. Global Radiative Forcing of Coupled Tropospheric Ozone and Aerosols in a Unified General Circulation Model

    NASA Technical Reports Server (NTRS)

    Liao, Hong; Seinfeld, John H.; Adams, Peter J.; Mickley, Loretta J.

    2008-01-01

    Global simulations of sea salt and mineral dust aerosols are integrated into a previously developed unified general circulation model (GCM), the Goddard Institute for Space Studies (GISS) GCM II', that simulates coupled tropospheric ozone-NOx-hydrocarbon chemistry and sulfate, nitrate, ammonium, black carbon, primary organic carbon, and secondary organic carbon aerosols. The fully coupled gas-aerosol unified GCM allows one to evaluate the extent to which global burdens, radiative forcing, and eventually climate feedbacks of ozone and aerosols are influenced by gas-aerosol chemical interactions. Estimated present-day global burdens of sea salt and mineral dust are 6.93 and 18.1 Tg with lifetimes of 0.4 and 3.9 days, respectively. The GCM is applied to estimate current top of atmosphere (TOA) and surface radiative forcing by tropospheric ozone and all natural and anthropogenic aerosol components. The global annual mean value of the radiative forcing by tropospheric ozone is estimated to be +0.53 W m(sup -2) at TOA and +0.07 W m(sup -2) at the Earth's surface. Global, annual average TOA and surface radiative forcing by all aerosols are estimated as -0.72 and -4.04 W m(sup -2), respectively. While the predicted highest aerosol cooling and heating at TOA are -10 and +12 W m(sup -2) respectively, surface forcing can reach values as high as -30 W m(sup -2), mainly caused by the absorption by black carbon, mineral dust, and OC. We also estimate the effects of chemistry-aerosol coupling on forcing estimates based on currently available understanding of heterogeneous reactions on aerosols. Through altering the burdens of sulfate, nitrate, and ozone, heterogeneous reactions are predicted to change the global mean TOA forcing of aerosols by 17% and influence global mean TOA forcing of tropospheric ozone by 15%.

  6. Effects of ozone and sulfuric acid aerosol on gas trapping in the guinea pig lung

    SciTech Connect

    Silbaugh, S.A.; Mauderly, J.L.

    1986-01-01

    Four groups of 20 guinea pigs were sequentially exposed by inhalation to either air followed by sulfuric acid aerosol, ozone followed by sulfuric acid aerosol, ozone followed by air, or air followed by air to determine whether ozone preexposure sensitizes guinea pigs to the airway constrictive effects of sulfuric acid aerosol. All first exposures to ozone or air were 2 h in duration; all second exposures to sulfuric acid or air were for 1 h. All ozone and sulfuric acid exposures were 0.8 ppm and 12 mg/m3, respectively. Animals were observed for respiratory distress during exposure, and excised lungs were quantitated for trapped gas and wet/dry ratios. None of the guinea pigs developed dyspnea, and wet/dry ratios were not altered. Ozone significantly (p less than 0.05) increased trapped gas volumes, which were 44% (ozone-acid) to 68% (ozone-air) greater than in the air-air group. Trapped gas volume was 23% greater in the ozone-acid group than in the air-acid group, but the difference was not statistically significant (p less than 0.20). Thus, ozone increased gas trapping but did not significantly sensitize guinea pigs to the bronchoconstrictive action of sulfuric acid.

  7. CART and GSFC raman lidar measurements of atmospheric aerosol backscattering and extinction profiles for EOS validation and ARM radiation studies

    NASA Technical Reports Server (NTRS)

    Ferrare, R. A.; Turner, D. D.; Melfi, S. H.; Whiteman, D. N.; Schwenner, G.; Evans, K. D.; Goldsmith, J. E. M.; Tooman, T.

    1998-01-01

    The aerosol retrieval algorithms used by the Moderate-Resolution Imaging Spectroradiometer (MODIS) and Multi-Angle Imaging SpectroRadiometer (MISR) sensors on the Earth Observing Satellite (EOS) AM-1 platform operate by comparing measured radiances with tabulated radiances that have been computed for specific aerosol models. These aerosol models are based almost entirely on surface and/or column averaged measurements and so may not accurately represent the ambient aerosol properties. Therefore, to validate these EOS algorithms and to determine the effects of aerosols on the clear-sky radiative flux, we have begun to evaluate the vertical variability of ambient aerosol properties using the aerosol backscattering and extinction profiles measured by the Cloud and Radiation Testbed (CART) and NASA Goddard Space Flight Center (GSFC) Raman Lidars. Using the procedures developed for the GSFC Scanning Raman Lidar (SRL), we have developed and have begun to implement algorithms for the CART Raman Lidar to routinely provide profiles of aerosol extinction and backscattering during both nighttime and ,daytime operations. Aerosol backscattering and extinction profiles are computed for both lidar systems using data acquired during the 1996 and 1997 Water Vapor Intensive Operating Periods (IOPs). By integrating these aerosol extinction profiles, we derive measurements of aerosol optical thickness and compare these with coincident sun photometer measurements. We also use these measurements to measure the aerosol extinction/backscatter ratio S(sub a) (i.e. 'lidar ratio'). Furthermore, we use the simultaneous water vapor measurements acquired by these Raman lidars to investigate the effects of water vapor on aerosol optical properties.

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

    NASA Technical Reports Server (NTRS)

    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.

  9. Modified cavity attenuated phase shift (CAPS) method for airborne aerosol light extinction measurement

    NASA Astrophysics Data System (ADS)

    Perim de Faria, Julia; Bundke, Ulrich; Freedman, Andrew; Petzold, Andreas

    2015-04-01

    Monitoring the direct impact of aerosol particles on climate requires the consideration of at least two major factors: the aerosol single-scattering albedo, defined as the relation between the amount of energy scattered and extinguished by an ensemble of aerosol particles; and the aerosol optical depth, calculated from the integral of the particle extinction coefficient over the thickness of the measured aerosol layer. Remote sensing networks for measuring these aerosol parameters on a regular basis 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. In particular, the CAPS PMex particle optical extinction monitor has demonstrated sensitivity of less than 2 Mm-1 in 1 second sampling period; with a 60 s averaging time, a detection limit of less than 0.3 Mm-1 can be achieved. 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. Here, we report on the modifications of a CAPS PMex instrument for measuring aerosol light extinction on aircraft, and subsequent laboratory tests for evaluating the modified instrument prototype: (1) In a

  10. Aerosol-induced chemical perturbations of stratospheric ozone: Three-dimensional simulations and analysis of mechanisms

    NASA Astrophysics Data System (ADS)

    Zhao, Xuepeng; Turco, Richard P.; Kao, C.-Y. Jim; Elliott, Scott

    1997-02-01

    An atmospheric general circulation model is coupled with a stratospheric photochemical model to simulate the chemical/dynamical perturbations associated with background and volcanically perturbed aerosols in the lower stratosphere. The present work focuses on short-term anomalies at middle and high latitudes in the northern hemisphere, where large ozone depletions have been observed in late winter and early spring, particularly following the eruption of Mount Pinatubo. Five fully coupled simulations are analyzed, corresponding to a control case with only gas phase chemistry, and cases including heterogeneous chemistry on background aerosols, on El Chichón-type, and on Pinatubo-type aerosols. It is found that heterogeneous reactions occurring on sulfate aerosols (background or postvolcanic) can strongly perturb the chemical partitioning in the lower stratosphere, leading to significant ozone depletion through enhanced chlorine, bromine, and odd-hydrogen catalytic cycles. In the Arctic lower stratosphere, the maximum zonal and March monthly mean local ozone reductions (with respect to the control case) can exceed 15% for the background aerosol case, 40% for the El Chichón case, and 50% for the Pinatubo case. The corresponding zonal mean total column ozone decreases are roughly 5% and 15% for the background and volcanic aerosol cases, respectively. In the most extreme case tested (post-Pinatubo), a large ozone depletion below 30 mbar is offset to some extent by an ozone increase above that level. The results of a sensitivity study (in which the aerosols are distributed closer to the tropics, as might occur early after an eruption at low latitude) lead to relatively small total ozone depletions at northern high latitudes, and small ozone increases in the tropical lower stratosphere. The reduced impact on total ozone at high latitudes is associated both with local ozone increases above 30 mbar and with poleward transport of enhanced ozone from the tropical lower

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

    SciTech Connect

    Weisenstein, D.K.; Ko, M.K.W.; Rodriguez, J.M.; Sze, N.

    1993-12-01

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

  12. Comparison of vertical aerosol extinction coefficients from in-situ and LIDAR measurements

    NASA Astrophysics Data System (ADS)

    Rosati, B.; Herrmann, E.; Bucci, S.; Fierli, F.; Cairo, F.; Gysel, M.; Tillmann, R.; Größ, J.; Gobbi, G. P.; Di Liberto, L.; Di Donfrancesco, G.; Wiedensohler, A.; Weingartner, E.; Virtanen, A.; Mentel, T. F.; Baltensperger, U.

    2015-07-01

    Vertical profiles of aerosol optical properties were explored in a case study near the San Pietro Capofiume (SPC) ground station during the PEGASOS Po Valley campaign in the summer of 2012. A Zeppelin NT airship was employed to investigate the effect of the dynamics of the planetary boundary layer at altitudes between ~ 50-800 m above ground. Determined properties included the aerosol size distribution, the hygroscopic growth factor, the effective index of refraction and the light absorption coefficient. The first three parameters were used to retrieve the light scattering coefficient. Simultaneously, direct measurements of both the scattering and absorption coefficient were carried out at the SPC ground station. Additionally, a LIDAR system provided aerosol extinction coefficients for a vertically resolved comparison between in-situ and remote sensing results. First, the airborne results at low altitudes were validated with the ground measurements. Agreement within approximately ±25 and ±20% was found for the dry scattering and absorption coefficient, respectively. The single scattering albedo, ranged between 0.83 to 0.95, indicating the importance of the absorbing particles in the Po Valley region. A clear layering of the atmosphere was observed during the beginning of the flight (until ~ 10 local time) before the mixed layer (ML) was fully developed. Highest extinction coefficients were found at low altitudes, in the new ML, while values in the residual layer, which could be probed at the beginning of the flight at elevated altitudes, were lower. At the end of the flight (after ~ 12 local time) the ML was fully developed, resulting in constant extinction coefficients at all altitudes measured on the Zeppelin NT. LIDAR results captured these dynamic features well and good agreement was found for the extinction coefficients compared to the in-situ results, using fixed LIDAR ratios (LR) between 30 and 70 sr for the altitudes probed with the Zeppelin. These LR are

  13. Effect of coagulation on extinction in an aerosol plume propagating in the atmosphere.

    PubMed

    Tsang, T H; Brock, J R

    1982-05-01

    Model studies based on the K-theory diffusion assumption have been carried out on aerosol plumes issuing from a crosswind line source in which advection, vertical diffusion, coagulation, sedimentation, and dry deposition are occurring. Procedures are described and a few typical results are presented. It is shown that in appropriate conditions coagulation can play an important role in altering extinction in the plume. An important coupling effect between coagulation and sedimentation/deposition has been demonstrated. In a coagulating plume it is found that total particle mass concentration cannot be inferred from measurements of extinction without a detailed consideration of the effects of coagulation. In realistic atmospheric simulations isopleths of extinction in the plume cross section show complex forms resulting from the wind gradient and its interactions with vertical diffusion and the coagulation and sedimentation/deposition processes. PMID:20389900

  14. Use of Lidar Derived Optical Extinction and Backscattering Coefficients Near Cloud Base to Explore Aerosol-Cloud Interactions

    NASA Astrophysics Data System (ADS)

    Han, Zaw; Wu, Yonhgua; Gross, Barry; Moshary, Fred

    2016-06-01

    Combination of microwave radiometer (MWR) and mutlifilter rotating shadowband radiometer (MFRSR) measurement data together with SBDART radiative transfer model to compute cloud optical depth (COD) and cloud droplet effective radius (Reff). Quantify the first aerosol indirect effect using calculated Reff and aerosol extinction from Raman lidar measurement in urban coastal region. Illustrate comparison between ground-based and satellite retrievals. Demonstrate relationship between surface aerosol (PM2.5) loading and Reff. We also explain the sensitivity of aerosol-cloud-index (ACI) depend on the aerosol layer from cloud base height. Potential used of less noisy elastic backscattering to calculate the ACI instead of using Raman extinction. We also present comparison of elastic backscattering and Raman extinction correlation to Reff.

  15. SAGE III Aerosol Extinction Validation in the Arctic Winter: Comparisons with SAGE II and POAM III

    NASA Technical Reports Server (NTRS)

    Thomason, L. W.; Poole, L. R.; Randall, C. E.

    2007-01-01

    The use of SAGE III multiwavelength aerosol extinction coefficient measurements to infer PSC type is contingent on the robustness of both the extinction magnitude and its spectral variation. Past validation with SAGE II and other similar measurements has shown that the SAGE III extinction coefficient measurements are reliable though the comparisons have been greatly weighted toward measurements made at mid-latitudes. Some aerosol comparisons made in the Arctic winter as a part of SOLVE II suggested that SAGE III values, particularly at longer wavelengths, are too small with the implication that both the magnitude and the wavelength dependence are not reliable. Comparisons with POAM III have also suggested a similar discrepancy. Herein, we use SAGE II data as a common standard for comparison of SAGE III and POAM III measurements in the Arctic winters of 2002/2003 through 2004/2005. During the winter, SAGE II measurements are made infrequently at the same latitudes as these instruments. We have mitigated this problem through the use potential vorticity as a spatial coordinate and thus greatly increased the number of coincident events. We find that SAGE II and III extinction coefficient measurements show a high degree of compatibility at both 1020 nm and 450 nm except a 10-20% bias at both wavelengths. In addition, the 452 to 1020-nm extinction ratio shows a consistent bias of approx. 30% throughout the lower stratosphere. We also find that SAGE II and POAM III are on average consistent though the comparisons show a much higher variability and larger bias than SAGE II/III comparisons. In addition, we find that the two data sets are not well correlated below 18 km. Overall, we find both the extinction values and the spectral dependence from SAGE III are robust and we find no evidence of a significant defect within the Arctic vortex.

  16. Forecasting of aerosol extinction of the sea and coastal atmosphere surface layer

    NASA Astrophysics Data System (ADS)

    Kaloshin, G. A.

    2010-04-01

    The focus of our study is the extinction and optical effects due to aerosol in a specific coastal region. The aerosol microphysical model of the marine and coastal atmosphere surface layer is considered. The model is made on the basis of the long-term experimental data received at researches of aerosol sizes distribution function (dN/dr) in the band particles sizes in 0.01 - 100 μk. The model is developed by present time for the band of heights is 0 - 25 m. Bands of wind speed is 3 - 18 km/s, sizes fetch is up to 120 km, RH = 40 - 98 %. Key feature of model is parameterization of amplitude and width of the modes as functions of fetch and wind speed. In the paper the dN/dr behavior depending at change meteorological parameters, heights above sea level, fetch (X), wind speed (U) and RH is show. On the basis of the developed model with usage of Mie theory for spheres the description of last version of developed code MaexPro (Marine Aerosol Extinction Profiles) for spectral profiles of aerosol extinction coefficients α(λ) calculations in the wavelength band, equal λ = 0.2 - 12 μm is presented. The received results are compared models NAN and ANAM. Also α(λ) profiles for various wind modes (combinations X and U) calculated by MaexPro code are given. The calculated spectrums of α(λ) profiles are compared with experimental data of α(λ) received by a transmission method in various geographical areas.

  17. Reactions of Complex Phenols on Aerosols with Gaseous Ozone

    NASA Astrophysics Data System (ADS)

    Hoffmann, M. R.; Enami, S.; Colussi, A. J.

    2009-12-01

    We report that α-tocopherol (α-TOH/α-TO-), as a model of substituted phenols in atmosphere, reacts with closed shell O3(g) on the surface of inert solvent microdroplets within 1 ms to produce persistent (n = 1 - 4) adducts detectable by online electrospray ionization mass spectrometry. The prototype phenolate PhO- undergoes electron transfer under identical conditions. These reactions occur at the gas/liquid interface since their rates: (1) depend on pH, (2) are several orders of magnitude faster than those in the bulk of O33-saturated microdroplets, and (3) approach O3(g) mass accommodation rates. Furthermore, they fail to incorporate solvent into the products: the same species are formed on acetonitrile or nucleophilic methanol microdroplets. Signals initially evolve with the concentration of ozone as expected from first-generation species. However, α-TO- reacts further with ozone via a collision-induced dissociation into a C19H40 fragment (vs. C19H38 from α-TO-, carrying the phytyl side-chain, whereas the higher homologues (α-TO-On ≥ 2-) are not reactive with O3(g). On this basis, α-TO- is assigned to a chroman-6-ol (4a, 8a)-ene oxide (an epoxide), α-TO-O2- to an endoperoxide, and α-TO-O3- to a secondary ozonide. These products are previous unreported. The atmospheric degradation of the substituted phenols detected in forest fires and combustion emissions is therefore expected to produce related oxidants on aerosol particles.

  18. 2003 megafires in Australia: impact on tropospheric ozone and aerosols

    NASA Astrophysics Data System (ADS)

    Guerova, G.; Jones, N.

    2009-01-01

    2003 was a record year for wildfires worldwide. Severe forest fires killed four people, displaced 20 500 others and burnt 260 000 ha in South-East Australia in January 2003. The uncontrolled fires ignited in early January 2003 as a result of a prolonged El Niño drought in South-East Australia. Severe weather conditions resulted in a fast spread of the fires and poor air quality in a region where 70% of the population of Australia lives. We use state-of-art global chemistry and transport model GEOS-Chem in conjunction with ground- and space-based observations to study the ozone (O3) and aerosol enhancement due to fires. Firstly, the monthly mean surface O3 and Aerosol Optical Depth (AOD) in January 2003 are compared to January 2004 and, secondly, from sensitivity model simulations, four episodes are isolated and an attempt is made to quantify the contribution of the fires to air quality in south and South-East Australia. In January 2003 the observed monthly mean afternoon surface O3 in Victoria (VIC) and South Australia (SA) reached 27.5 ppb, which is 6.5 ppb (i.e. 30%) higher than in 2004. The simulated O3 is 29.5 ppb, which is 10 ppb higher than in 2004. While the model tends to overestimate the observed peak O3, it exhibits very good skill in reproducing the O3 temporal variability in January 2003 with a correlation of 0.83. In VIC, the air quality 4-h ozone (O3) standard exceedences are reported on 17, 24 and 25 January. On 12, 17, 24-25 and 29 January 2003, the observed O3 peaks above 40 ppb and the simulated fire contribution is higher than 10 ppb. During these 4 episodes, the range of observed O3 enhancement due to fires is 20-35 ppb, which is a factor of 3 to 5 higher than the monthly mean. The simulated fire O3 enhancement is in the range 15-50 ppb with a factor of 1.5 to 5 higher than the monthly mean. During two episodes, a well-formed surface wind channel stretches across the Tasman Sea facilitating the long range transport to New Zealand contributing

  19. Secondary organic aerosol formation initiated from reactions between ozone and surface-sorbed squalene

    NASA Astrophysics Data System (ADS)

    Wang, Chunyi; Waring, Michael S.

    2014-02-01

    Previous research has shown that ozone reactions on surface-sorbed D-limonene can promote gas phase secondary organic aerosol (SOA) formation indoors. In this work, we conducted 13 steady state chamber experiments to measure the SOA formation entirely initiated by ozone reactions with squalene sorbed to glass, at chamber ozone of 57-500 ppb for two relative humidity (RH) conditions of 21% and 51%, in the absence of seed particles. Squalene is a nonvolatile compound that is a component of human skin oil and prevalent on indoor surfaces and in settled dust due to desquamation. The size distributions, mass and number secondary emission rates (SER), aerosol mass fractions (AMF), and aerosol number fractions (ANF) of formed SOA were quantified. The surface AMF and ANF are defined as the change in SOA mass or number formed, respectively, per ozone mass consumed by ozone-squalene reactions. All experiments but one exhibited nucleation and mass formation. Mass formation was relatively small in magnitude and increased with ozone, most notably for the RH = 51% experiments. The surface AMF was a function of the chamber aerosol concentration, and a multi-product model was fit using the 'volatility basis set' framework. Number formation was relatively strong at low ozone and low RH conditions. Though we cannot extrapolate our results because experiments were conducted at high air exchange rates, we speculate that this process may enhance particle number more than mass concentrations indoors.

  20. Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band

    SciTech Connect

    Flittner, D.E.; Herman, B.M.; Thome, K.J.; Simpson, J.M.; Reagan, J.A. )

    1993-04-15

    A second-derivative smoothing technique, commonly used in inversion work, is applied to the problem of inferring total columnar ozone amounts and aerosol optical depths. The application is unique in that the unknowns (i.e., total columnar ozone and aerosol optical depth) may be solved for directly without employing standard inversion methods. It is shown, however, that by employing inversion constraints, better solutions are normally obtained. The current method requires radiometric measurements of total optical depth through the Chappuis ozone band. It assumes no a priori shape for the aerosol optical depth versus wavelength profile and makes no assumptions about the ozone amount. Thus, the method is quite versatile and able to deal with varying total ozone and various aerosol size distributions. The technique is applied first in simulation, then to 119 days of measurements taken in Tucson, Arizona, that are compared to TOMS values for the same dates. The technique is also applied to two measurements taken at Mauna Loa, Hawaii, for which Dobson ozone values are available in addition to the TOMS values, and the results agree to within 15%. It is also shown through simulations that additional information can be obtained from measurements outside the Chappuis band. This approach reduces the bias and spread of the estimates total ozone and is unique in that it uses measurements from both the Chappuis and Huggins absorption bands. 12 refs., 6 figs., 2 tabs.

  1. Measurements of total column ozone, precipitable water content and aerosol optical depth at Sofia

    NASA Astrophysics Data System (ADS)

    Kaleyna, P.; Kolev, N.; Savov, P.; Evgenieva, Ts.; Danchovski, V.; Muhtarov, P.

    2016-03-01

    This article reports the results of a study related to variations in total ozone content, aerosol optical depth, water vapor content and Ångström coefficients from summer campaign carried out in June-July 2014, at two sites in the city of Sofia (Astronomical Observatory in the Borisova Gradina Park and National Institute of Geophysics, Geodesy and Geography (NIGGG)). The results of data analysis indicate the following: Spectral dependence of aerosol optical depth (AOD); Greater AOD values due to greater portion of aerosols; Inverse relationship between the time variations of AOD or water vapor and ozone.

  2. Effect of stratospheric aerosol layers on the TOMS/SBUV ozone retrieval

    NASA Technical Reports Server (NTRS)

    Torres, O.; Ahmad, Zia; Pan, L.; Herman, J. R.; Bhartia, P. K.; Mcpeters, R.

    1994-01-01

    An evaluation of the optical effects of stratospheric aerosol layers on total ozone retrieval from space by the TOMS/SBUV type instruments is presented here. Using the Dave radiative transfer model we estimate the magnitude of the errors in the retrieved ozone when polar stratospheric clouds (PSC's) or volcanic aerosol layers interfere with the measurements. The largest errors are produced by optically thick water ice PSC's. Results of simulation experiments on the effect of the Pinatubo aerosol cloud on the Nimbus-7 and Meteor-3 TOMS products are presented.

  3. Aerosol Backscatter and Extinction Retrieval from Airborne Coherent Doppler Wind Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Chouza, F.; Reitebuch, O.; Groß, S.; Rahm, S.; Freudenthaler, V.; Toledano, C.; Weinzierl, B.

    2016-06-01

    A novel method for coherent Doppler wind lidars (DWLs) calibration is shown in this work. Concurrent measurements of a ground based aerosol lidar operating at 532 nm and an airborne DWL at 2 μm are used in combination with sun photometer measurements for the retrieval of backscatter and extinction profiles. The presented method was successfully applied to the measurements obtained during the Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE: http://www.pa.op.dlr.de/saltrace), which aimed to characterize the Saharan dust long range transport between Africa and the Caribbean.

  4. Analysis of Antarctic stratospheric aerosol properties using SAGE II extinction measurements

    NASA Technical Reports Server (NTRS)

    Thomason, Larry W.; Poole, Lamont R.

    1992-01-01

    Multispectra aerosol extinction data for the fall and spring of 1987 measured by the SAGE II sensor are employed to determine the physical characteristics of aerosols within the springtime Antarctic polar vortex. Attention is given to the physical processes that give rise to the apparent springtime 'cleansing' of the Antarctic stratosphere. The inferred vertical and radial structure compare favorably with in situ measurements but yield a previously unavailable 2D structure to the distribution of aerosols within the polar vortex. The springtime 'cleansing' of the Antarctic stratosphere is found to be a result of both large-scale subsidence and the preferential removal of large particles by the nucleation and subsequent sedimentation of polar stratospheric clouds.

  5. The impacts of aerosol loading, composition, and water uptake on aerosol extinction variability in the Baltimore-Washington, D.C. region

    NASA Astrophysics Data System (ADS)

    Beyersdorf, A. J.; Ziemba, L. D.; Chen, G.; Corr, C. A.; Crawford, J. H.; Diskin, G. S.; Moore, R. H.; Thornhill, K. L.; Winstead, E. L.; Anderson, B. E.

    2016-01-01

    In order to utilize satellite-based aerosol measurements for the determination of air quality, the relationship between aerosol optical properties (wavelength-dependent, column-integrated extinction measured by satellites) and mass measurements of aerosol loading (PM2.5 used for air quality monitoring) must be understood. This connection varies with many factors including those specific to the aerosol type - such as composition, size, and hygroscopicity - and to the surrounding atmosphere, such as temperature, relative humidity (RH), and altitude, all of which can vary spatially and temporally. During the DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) project, extensive in situ atmospheric profiling in the Baltimore, MD-Washington, D.C. region was performed during 14 flights in July 2011. Identical flight plans and profile locations throughout the project provide meaningful statistics for determining the variability in and correlations between aerosol loading, composition, optical properties, and meteorological conditions. Measured water-soluble aerosol mass was composed primarily of ammonium sulfate (campaign average of 32 %) and organics (57 %). A distinct difference in composition was observed, with high-loading days having a proportionally larger percentage of sulfate due to transport from the Ohio River Valley. This composition shift caused a change in the aerosol water-uptake potential (hygroscopicity) such that higher relative contributions of inorganics increased the bulk aerosol hygroscopicity. These days also tended to have higher relative humidity, causing an increase in the water content of the aerosol. Conversely, low-aerosol-loading days had lower sulfate and higher black carbon contributions, causing lower single-scattering albedos (SSAs). The average black carbon concentrations were 240 ng m-3 in the lowest 1 km, decreasing to 35 ng m-3 in the free troposphere (above

  6. Development of the code MaexPro for calculation atmospheric aerosol extinction in the marine and coastal surface layer

    NASA Astrophysics Data System (ADS)

    Kaloshin, Gennady A.; Shishkin, Sergey A.; Serov, Sergey A.

    2006-11-01

    In the paper the description of the last version of the code MaexPro (Marine aerosol extinction Profile) for calculation spectral and vertical profiles of aerosol extinction coefficient α( λ), aerosol sizes distribution, area distribution, volumes distribution, modes aerosol extinction spectra using standard meteorological parameters, aerosol microphysical structure, a spectral band and a height of the sensor location place is submitted. The code MaexPro is the computer program under constantly development to estimate of EO systems signal power at a location place in which a fetch is key entrance parameter. Spectral behavior α( λ) can be submitted as graphically, and as tables. Commands overplot for superposition or change of figures; profiles extrapolation; a lens; all kinds of possible copying; the data presentation, convenient for an input in code MODTRAN, and etc. are stipulated. The code MaexPro is a completely mouse-driven PC Windows program with a user-friendly interface. Calculation time of spectral and vertical profiles of α( λ) depends on the necessary wave length resolution, radius of aerosol particles and the location place height, and does not exceed tens seconds for each new meteorological condition. Other calculations characteristics, such as aerosol sizes distribution, area distribution, volumes distribution, modes aerosol extinction spectra, are performed in a few seconds.

  7. Statistical analysis of the spatial-temporal distribution of aerosol extinction retrieved by micro-pulse lidar in Kashgar, China.

    PubMed

    Zhu, Wenyue; Xu, Chidong; Qian, Xianmei; Wei, Heli

    2013-02-11

    The spatial-temporal distribution of dust aerosol is important in climate model and ecological environment. An observation experiment of the aerosol vertical distribution in the low troposphere was made using the micro-pulse lidar system from Sept. 2008 to Aug. 2009 at the oasis city Kashgar, China, which is near the major dust source area of the Taklimakan desert. The monthly averaged temporal variation of aerosol extinction profiles are given in the paper. The profile of aerosol extinction coefficient suggested that the dust aerosol could be vertically transported from the ground level to the higher altitude of above 5 km around the source region, and the temporal distribution showed that the dust aerosol layer of a few hundred meters thick appeared in the seasons of early spring and summer near the ground surface. PMID:23481711

  8. Relationships between Optical Extinction, Backscatter and Aerosol Surface and Volume in the Stratosphere following the Eruption of Mt. Pinatubo

    NASA Technical Reports Server (NTRS)

    Brock, Charles A.; Jonsson, Haflidi H.; Wilson, James C.; Dye, James E.; Baumgardner, Darrel; Borrmann, Stephan; Pitts, Mike C.; Osborn, Mary T.; DeCoursey, Robert J.; Woods, David C.

    1993-01-01

    The eruption of the Mt. Pinatubo volcano in the Philippines in June 1991 has resulted in increases in the surface and mass concentrations of aerosol particles in the lower stratosphere. Airborne measurements made at midlatitudes between 15 and 21 km from August 1991 to March 1992 show that, prior to December 1991, the Pinatubo aerosol cloud varied widely in microphysical properties such as size distribution, number, surface and volume concentrations and was also spatially variable. Aerosol surface area concentration was found to be highly correlated to extinction at visible and near-infrared wavelengths throughout the measurement period. Similarly, backscatter at common lidar wavelengths was a good predictor of aerosol volume concentrations. These results support the use of satellite extinction measurements to estimate aerosol surface and of lidar measurements to estimate aerosol volume or mass if temporal changes in the relationships between the variables are considered.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  10. Cavity Attenuated Phase Shift (CAPS) Method for Airborne Aerosol Light Extinction Measurement: Instrument Validation and First Results from Field Deployment

    NASA Astrophysics Data System (ADS)

    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 < 5%) with theoretical values calculated from Rayleigh scattering cross-sections, when operated on pressurized air and CO2 at ambient and low pressure (~200 hPa). For monodisperse and polydisperse aerosols, reference aerosol extinction coefficients were calculated from measured size distributions and agreed with the CAPS PMex instrument

  11. Using Airborne High Spectral Resolution Lidar Data to Evaluate Combined Active Plus Passive Retrievals of Aerosol Extinction Profiles

    NASA Technical Reports Server (NTRS)

    Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Kittaka, C.; Vaughn, M. A.; Remer, L. A.

    2010-01-01

    We derive aerosol extinction profiles from airborne and space-based lidar backscatter signals by constraining the retrieval with column aerosol optical thickness (AOT), with no need to rely on assumptions about aerosol type or lidar ratio. The backscatter data were acquired by the NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL) and by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. The HSRL also simultaneously measures aerosol extinction coefficients independently using the high spectral resolution lidar technique, thereby providing an ideal data set for evaluating the retrieval. We retrieve aerosol extinction profiles from both HSRL and CALIOP attenuated backscatter data constrained with HSRL, Moderate-Resolution Imaging Spectroradiometer (MODIS), and Multiangle Imaging Spectroradiometer column AOT. The resulting profiles are compared with the aerosol extinction measured by HSRL. Retrievals are limited to cases where the column aerosol thickness is greater than 0.2 over land and 0.15 over water. In the case of large AOT, the results using the Aqua MODIS constraint over water are poorer than Aqua MODIS over land or Terra MODIS. The poorer results relate to an apparent bias in Aqua MODIS AOT over water observed in August 2007. This apparent bias is still under investigation. Finally, aerosol extinction coefficients are derived from CALIPSO backscatter data using AOT from Aqua MODIS for 28 profiles over land and 9 over water. They agree with coincident measurements by the airborne HSRL to within +/-0.016/km +/- 20% for at least two-thirds of land points and within +/-0.028/km +/- 20% for at least two-thirds of ocean points.

  12. Tropospheric Ozone Lidar Network (TOLNet) - Long-term Tropospheric Ozone and Aerosol Profiling for Satellite Continuity and Process Studies

    NASA Astrophysics Data System (ADS)

    Newchurch, M.; Al-Saadi, J. A.; Alvarez, R. J.; Burris, J.; Cantrell, W.; Chen, G.; De Young, R.; Hardesty, R.; Hoff, R. M.; Kaye, J. A.; kuang, S.; Langford, A. O.; LeBlanc, T.; McDermid, I. S.; McGee, T. J.; Pierce, R.; Senff, C. J.; Sullivan, J. T.; Szykman, J.; Tonnesen, G.; Wang, L.

    2012-12-01

    An interagency research initiative for ground-based ozone and aerosol lidar profiling recently funded by NASA has important applications to air-quality studies in addition to the goal of serving the GEO-CAPE and other air-quality missions. Ozone is a key trace-gas species, a greenhouse gas, and an important pollutant in the troposphere. High spatial and temporal variability of ozone affected by various physical and photochemical processes motivates the high spatio-temporal lidar profiling of tropospheric ozone for improving the simulation and forecasting capability of the photochemical/air-quality models, especially in the boundary layer where the resolution and precision of satellite retrievals are fundamentally limited. It is well known that there are large discrepancies between the surface and upper-air ozone due to titration, surface deposition, diurnal processes, free-tropospheric transport, and other processes. Near-ground ozone profiling has been technically challenging for lidars due to some engineering difficulties, such as near-range saturation, field-of-view overlap, and signal processing issues. This initiative provides an opportunity for us to solve those engineering issues and redesign the lidars aimed at long-term, routine ozone/aerosol observations from the near surface to the top of the troposphere at multiple stations (i.e., NASA/GSFC, NASA/LaRC, NASA/JPL, NOAA/ESRL, UAHuntsville) for addressing the needs of NASA, NOAA, EPA and State/local AQ agencies. We will present the details of the science investigations, current status of the instrumentation development, data access/protocol, and the future goals of this lidar network. Ozone lidar/RAQMS comparison of laminar structures.

  13. Analysis of DIAL/HSRL aerosol backscatter and extinction profiles during the SEAC4RS campaign with an aerosol assimilation system

    NASA Astrophysics Data System (ADS)

    Weaver, C. J.; da Silva, A. M., Jr.; Colarco, P. R.; Randles, C. A.

    2015-12-01

    We retrieve aerosol concentrations and optical information from vertical profiles of airborne 532 nm extinction and 532 and 1064 nm backscatter measurements made during the SEAC4RS summer 2013 campaign. The observations are from the High Spectral Resolution Lidar (HSRL) Airborne Differential Absorption Lidar (DIAL) on board the NASA DC-8. Instead of retrieving information about aerosol microphysical properties such as indexes of refraction, we seek information more directly applicable to an aerosol transport model - in our case the Goddard Chemistry Aerosol Radiation and Transport (GOCART) module used in the GEOS-5 Earth modeling system. A joint atmosphere/aerosol mini-reanalysis was performed for the SEAC4RS period using GEOS-5. The meteorological reanalysis followed the MERRA-2 atmospheric reanalysis protocol, and aerosol information from MODIS, MISR, and AERONET provided a constraint on the simulated aerosol optical depth (i.e., total column loading of aerosols). We focus on the simulated concentrations of 10 relevant aerosol species simulated by the GOCART module: dust, sulfate, and organic and black carbon. Our first retrieval algorithm starts with the SEAC4RS mini-reanalysis and adjusts the concentration of each GOCART aerosol species so that differences between the observed and simulated backscatter and extinction measurements are minimized. In this case, too often we are unable to simulate the observations by simple adjustment of the aerosol concentrations. A second retrieval approach adjusts both the aerosol concentrations and the optical parameters (i.e., assigned mass extinction efficiency) associated with each GOCART species. We present results from DC-8 flights over smoke from forest fires over the western US using both retrieval approaches. Finally, we compare our retrieved quantities with in-situ observations of aerosol absorption, scattering, and mass concentrations at flight altitude.

  14. An effective inversion algorithm for retrieving bimodal aerosol particle size distribution from spectral extinction data

    NASA Astrophysics Data System (ADS)

    He, Zhenzong; Qi, Hong; Yao, Yuchen; Ruan, Liming

    2014-12-01

    The Ant Colony Optimization algorithm based on the probability density function (PDF-ACO) is applied to estimate the bimodal aerosol particle size distribution (PSD). The direct problem is solved by the modified Anomalous Diffraction Approximation (ADA, as an approximation for optically large and soft spheres, i.e., χ≫1 and |m-1|≪1) and the Beer-Lambert law. First, a popular bimodal aerosol PSD and three other bimodal PSDs are retrieved in the dependent model by the multi-wavelength extinction technique. All the results reveal that the PDF-ACO algorithm can be used as an effective technique to investigate the bimodal PSD. Then, the Johnson's SB (J-SB) function and the modified beta (M-β) function are employed as the general distribution function to retrieve the bimodal PSDs under the independent model. Finally, the J-SB and M-β functions are applied to recover actual measurement aerosol PSDs over Beijing and Shanghai obtained from the aerosol robotic network (AERONET). The numerical simulation and experimental results demonstrate that these two general functions, especially the J-SB function, can be used as a versatile distribution function to retrieve the bimodal aerosol PSD when no priori information about the PSD is available.

  15. Aerosol extinction properties over coastal West Bengal Gangetic plain under inter-seasonal and sea breeze influenced transport processes

    NASA Astrophysics Data System (ADS)

    Verma, S.; Priyadharshini, B.; Pani, S. K.; Bharath Kumar, D.; Faruqi, A. R.; Bhanja, S. N.; Mandal, M.

    2016-01-01

    We analysed the atmospheric aerosol extinction properties under an influence of inter-seasonal and sea breeze (SB) transport processes over coastal West Bengal (WB) Gangetic plain (WBGP). The predominant frequency of airmass back trajectory path was through the Arabian Sea (AS) during southwest monsoon (SWmon) and that through the Indo-Gangetic plain (IGP) during transition to winter (Twin) season and the Bay of Bengal during transition to summer (Tsumm) season. Aerosol surface concentration (Sconc) and aerosol extinction exhibited heterogeneity in the seasonal variability over coastal WBGP with their highest seasonal mean being during winter and summer seasons respectively. Seasonal mean extinction was respectively 17% and 30% higher during winter and summer seasons than that during SWmon. While angstrom exponent (AE) was less than one during SWmon, Tsumm, and summer seasons, it was near to one during Twin and winter monsoon (Wmon), and was more than one during winter season. Relative contribution (%) of upper (at altitude above 1 km) aerosol layer (UAL) to aerosol extinction during summer was four times of that during winter. Seasonally distinct vertical distribution of aerosol extinction associated with meteorological and SB influenced transport and that due to influence of high rise open burning emissions was inferred. Possible aerosol subtypes extracted during days in Tsumm were inferred to be mostly constituted of dust and polluted dust during daytime, in addition to polluted continental and smoke in UAL during nighttime. In contrast to that at nearby urban location (Kolkata, KOL), intensity of updraft of airmass evaluated during evening/SB activity hour (1730 local time, (LT)) at study site (Kharagpur, KGP) was as high as 3.5 times the intensity during near to noon hour (1130 LT); this intensity was the highest along coast of westBengal-Orissa. Enhanced Sconc and relative contribution of UAL to aerosol extinction (58% compared to 36% only at nearby urban

  16. Simulation of improved daytime capabilities to retrieve aerosol extinction coefficient using Rotational Raman lidars

    NASA Astrophysics Data System (ADS)

    Madonna, Fabio; Amodeo, Aldo

    2015-04-01

    So far, most of the multi-wavelength Raman lidar observations of aerosols are performed at night, because Raman signals are weak compared to daylight background. Different techniques have been developed to improve Raman lidar daytime capabilities in the past years. Indeed, the retrieval of aerosol extinction during daytime is feasible through the detection of backscattered radiation due to the pure Rotational Raman Spectrum (PRRS) of molecular nitrogen or oxygen, much brighter than the vibration-rotation spectrum. The existing techniques for the measure of PRRS are based on small-bandwidth emitter and receiver systems and on a small receiver field of view to suppress the daylight background. They have been successfully tested and implemented in a few systems which are already in operational use within EARLINET (European Aerosol research Lidar NETwork). In this work, several different configurations used as receiver for a lidar system detecting the PRRS in daytime conditions are compared by means of numerical simulations. The configurations are mainly differentiated by the design of the spectral selection unit implemented in the receiver of each lidar system, based on a narrow-bandwidth filters, broad-band filters, grating spectrometers, and hybrid solutions. The research of configurations able to be more easily implemented on a large number of lidar systems within ACTRIS are explored. To show the performances of the investigated lidar configurations, a blind test has been carried out to get the simulated performances in the retrieval of the aerosol extinction profile during night-time and daytime starting from a known scenario. The atmospheric scenario used as the reference profile is represented by one of the night-time measurements with MUSA (MUlti-wavelength system for Aerosol) lidar at CNR-IMAA Atmospheric Observatory - CIAO (15.72E, 40.60N , 760 m a.s.l., Potenza, Italy). Though all the configuration considered in the blind test proved to be solid to

  17. Volcanic aerosol and ozone depletion within the Antarctic polar vortex during the austral spring of 1991

    SciTech Connect

    Deshler, T.; Adriani, A.; Gobbi, G.P.; Hofmann, D.J.; Donfrancesco, G. di; Johnson, B.J. CNR, Ist. de Fisica dell'Atmosfera, Frascati NOAA, Climate Monitoring and Diagnostics Lab., Boulder, CO ENEA, Centro Ricerche Energia Casaccia, Rome )

    1992-09-01

    In the spring of 1991 the Antarctic lower stratosphere was characterized by a layer of volcanic aerosol from the Cerro Hudson eruption. This aerosol layer was observed from McMurdo Station, Antarctica, with both lidar and balloonborne particle counters beginning around 10 September. After 20 September the aerosol was observed daily between 9 and 13 km. In this layer homogeneous nucleation of new aerosol was observed with concentrations greater than 6000/cu cm. Comparisons of scattering ratio calculated from measured particle size distributions agree best with the lidar measurements when a real index of refraction near 1.5 is used. In the past 5 years of measurements, ozone below 13 km has been relatively unchanged during the annual Antartic ozone depletion; however, in 1991 ozone below 13 km decreased at a rate of 4 - 8 ppb/day over 30 days. This change began shortly after the appearance of the volcanic aerosol, providing direct measurements correlating volcanic aerosol and ozone depletion. 16 refs.

  18. Modeling of growth and evaporation effects on the extinction of 1.0-micron solar radiation traversing stratospheric sulfuric acid aerosols

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Deepak, A.

    1981-01-01

    The effects of growth and evaporation of stratospheric sulfuric acid aerosols on the extinction of solar radiation traversing such an aerosol medium are reported for the case of 1.0-micron solar radiation. Modeling results show that aerosol extinction is not very sensitive to the change of ambient water vapor concentration, but is sensitive to ambient temperature changes, especially at low ambient temperatures and high ambient water vapor concentration. A clarification is given of the effects of initial aerosol size distribution and composition on the change of aerosol extinction due to growth and evaporation processes. It is shown that experiments designed to observe solar radiation extinction of aerosols may also be applied to the determination of observed changes in aerosol optical properties, environmental parameters, or the physical and optical characteristics of sulfate aerosols.

  19. Airborne high spectral resolution lidar for measuring aerosol extinction and backscatter coefficients.

    PubMed

    Esselborn, Michael; Wirth, Martin; Fix, Andreas; Tesche, Matthias; Ehret, Gerhard

    2008-01-20

    An airborne high spectral resolution lidar (HSRL) based on an iodine absorption filter and a high-power frequency-doubled Nd:YAG laser has been developed to measure backscatter and extinction coefficients of aerosols and clouds. The instrument was operated aboard the Falcon 20 research aircraft of the German Aerospace Center (DLR) during the Saharan Mineral Dust Experiment in May-June 2006 to measure optical properties of Saharan dust. A detailed description of the lidar system, the analysis of its data products, and measurements of backscatter and extinction coefficients of Saharan dust are presented. The system errors are discussed and airborne HSRL results are compared to ground-based Raman lidar and sunphotometer measurements. PMID:18204721

  20. Relationships between optical extinction, backscatter and aerosol surface and volume in the stratosphere following the eruption of Mt. Pinatubo

    NASA Technical Reports Server (NTRS)

    Brock, Charles A.; Jonsson, Haflidi H.; Wilson, James C.; Dye, James E.; Baumgardner, Darrel; Borrmann, Stephan; Pitts, Mike C.; Osborn, Mary T.; Decoursey, Robert J.; Woods, David C.

    1993-01-01

    The eruption of the Mt. Pinatubo volcano in the Philippines in June 1991 has resulted in increases in the surface and mass concentrations of aerosol particles in the lower stratosphere. Airborne measurements made at midlatitudes between 15 and 21 km from August 1991 to March 1992 show that, prior to December 1991, the Pinatubo aerosol cloud varied widely in microphysical properties such as size distribution, number, surface and volume concentrations and was also spatially variable. Aerosol surface area concentration was found to be highly correlated to extinction at visible and near-infrared wavelenghts throughout the measurement period. Similarly, backscatter at common lidar wavelengths was a good predictor of aerosol volume concentrations. These results support the use of satellite extinction measurements to estimate aerosol volume or mass if temporal changes in the relationships between the variables are considered.

  1. Balloonborne measurements of ozone and aerosol profiles at McMurdo Station, Antarctica, during the austral spring of 1992

    SciTech Connect

    Johnson, B.J.; Deshler, T. )

    1993-01-01

    This paper reports some of the findings of an overall study of the ozone hole over Antarctica. Vertical profiles of ozone and aerosols were measured, and the inclusion of aerosols from the June 1991 eruption of Mount Pinatubo was of particular interest. 4 refs., 2 figs.

  2. Use of rotational Raman measurements in multiwavelength aerosol lidar for evaluation of particle backscattering and extinction

    NASA Astrophysics Data System (ADS)

    Veselovskii, I.; Whiteman, D. N.; Korenskiy, M.; Suvorina, A.; Pérez-Ramírez, D.

    2015-10-01

    Vibrational Raman scattering from nitrogen is commonly used in aerosol lidars for evaluation of particle backscattering (β) and extinction (α) coefficients. However, at mid-visible wavelengths, particularly in the daytime, previous measurements have possessed low signal-to-noise ratio. Also, vibrational scattering is characterized by a significant frequency shift of the Raman component, so for the calculation of α and β information about the extinction Ångström exponent is needed. Simulation results presented in this study demonstrate that ambiguity in the choice of Ångström exponent can be the a significant source of uncertainty in the calculation of backscattering coefficients when optically thick aerosol layers are considered. Both of these issues are addressed by the use of pure-rotational Raman (RR) scattering, which is characterized by a higher cross section compared to nitrogen vibrational scattering, and by a much smaller frequency shift, which essentially removes the sensitivity to changes in the Ångström exponent. We describe a practical implementation of rotational Raman measurements in an existing Mie-Raman lidar to obtain aerosol extinction and backscattering at 532 nm. A 2.3 nm width interference filter was used to select a spectral range characterized by low temperature sensitivity within the anti-Stokes branch of the RR spectrum. Simulations demonstrate that the temperature dependence of the scattering cross section does not exceed 1.5 % in the 230-300 K range, making correction for this dependence quite easy. With this upgrade, the NASA GSFC multiwavelength Raman lidar has demonstrated useful α532 measurements and was used for regular observations. Examples of lidar measurements and inversion of optical data to the particle microphysics are given.

  3. Volcanic-aerosol-induced changes in stratospheric ozone following the eruption of Mount Pinatubo

    NASA Technical Reports Server (NTRS)

    Grant, W. B.; Browell, E. V.; Fishman, J.; Brackett, V. G.; Fenn, M. A.; Butler, C. F.; Nganga, D.; Minga, A.; Cros, B.; Mayor, S. D.

    1994-01-01

    Measurements of lower stratospheric ozone in the Tropics using electrochemical concentrations cell (ECC) sondes and the airborne UV Differential Absorption Lidar (DIAL) system after the eruption of Mt. Pinatubo are compared with the Stratospheric Aerosol and Gas Experiment 2 (SAGE 2) and ECC sonde measurements from below the eruption to determine what changes have occurred as a result. Aerosol data from the Advanced Very High Resolution Radiometer (AVHRR) and the visible and IR wavelengths of the lidar system are used to examine the relationship between aerosols and ozone changes. Ozone decreases of 30 percent at altitudes between 19 and 26 km, partial column (16-28 km) decreases of about 27 D.U., and slight increases (5.4 D.U.) between 28 and 31 km are found in comparison with SAGE 2 climatological values.

  4. Studying the vertical aerosol extinction coefficient by comparing in situ airborne data and elastic backscatter lidar

    NASA Astrophysics Data System (ADS)

    Rosati, Bernadette; Herrmann, Erik; Bucci, Silvia; Fierli, Federico; Cairo, Francesco; Gysel, Martin; Tillmann, Ralf; Größ, Johannes; Gobbi, Gian Paolo; Di Liberto, Luca; Di Donfrancesco, Guido; Wiedensohler, Alfred; Weingartner, Ernest; Virtanen, Annele; Mentel, Thomas F.; Baltensperger, Urs

    2016-04-01

    Vertical profiles of aerosol particle optical properties were explored in a case study near the San Pietro Capofiume (SPC) ground station during the PEGASOS Po Valley campaign in the summer of 2012. A Zeppelin NT airship was employed to investigate the effect of the dynamics of the planetary boundary layer at altitudes between ˜ 50 and 800 m above ground. Determined properties included the aerosol particle size distribution, the hygroscopic growth factor, the effective index of refraction and the light absorption coefficient. The first three parameters were used to retrieve the light scattering coefficient. Simultaneously, direct measurements of both the scattering and absorption coefficient were carried out at the SPC ground station. Additionally, a single wavelength polarization diversity elastic lidar system provided estimates of aerosol extinction coefficients using the Klett method to accomplish the inversion of the signal, for a vertically resolved comparison between in situ and remote-sensing results. Note, however, that the comparison was for the most part done in the altitude range where the overlap function is incomplete and accordingly uncertainties are larger. First, the airborne results at low altitudes were validated with the ground measurements. Agreement within approximately ±25 and ±20 % was found for the dry scattering and absorption coefficient, respectively. The single scattering albedo, ranged between 0.83 and 0.95, indicating the importance of the absorbing particles in the Po Valley region. A clear layering of the atmosphere was observed during the beginning of the flight (until ˜ 10:00 LT - local time) before the mixing layer (ML) was fully developed. Highest extinction coefficients were found at low altitudes, in the new ML, while values in the residual layer, which could be probed at the beginning of the flight at elevated altitudes, were lower. At the end of the flight (after ˜ 12:00 LT) the ML was fully developed, resulting in

  5. Optical and Physicochemical Properties of Brown Carbon Aerosol: Light Scattering, FTIR Extinction Spectroscopy, and Hygroscopic Growth.

    PubMed

    Tang, Mingjin; Alexander, Jennifer M; Kwon, Deokhyeon; Estillore, Armando D; Laskina, Olga; Young, Mark A; Kleiber, Paul D; Grassian, Vicki H

    2016-06-23

    A great deal of attention has been paid to brown carbon aerosol in the troposphere because it can both scatter and absorb solar radiation, thus affecting the Earth's climate. However, knowledge of the optical and chemical properties of brown carbon aerosol is still limited. In this study, we have investigated different aspects of the optical properties of brown carbon aerosol that have not been previously explored. These properties include extinction spectroscopy in the mid-infrared region and light scattering at two different visible wavelengths, 532 and 402 nm. A proxy for atmospheric brown carbon aerosol was formed from the aqueous reaction of ammonium sulfate with methylglyoxal. The different optical properties were measured as a function of reaction time for a period of up to 19 days. UV/vis absorption experiments of bulk solutions showed that the optical absorption of aqueous brown carbon solution significantly increases as a function of reaction time in the spectral range from 200 to 700 nm. The analysis of the light scattering data, however, showed no significant differences between ammonium sulfate and brown carbon aerosol particles in the measured scattering phase functions, linear polarization profiles, or the derived real parts of the refractive indices at either 532 or 402 nm, even for the longest reaction times with greatest visible extinction. The light scattering experiments are relatively insensitive to the imaginary part of the refractive index, and it was only possible to place an upper limit of k ≤ 0.01 on the imaginary index values. These results suggest that after the reaction with methylglyoxal the single scattering albedo of ammonium sulfate aerosol is significantly reduced but that the light scattering properties including the scattering asymmetry parameter, which is a measure of the relative amount of forward-to-backward scattering, remain essentially unchanged from that of unprocessed ammonium sulfate. The optical extinction properties

  6. Ozone and secondary aerosol formation — Analysis of particle observations in the 2009 SHARP campaign

    NASA Astrophysics Data System (ADS)

    Cowin, J.; Yu, X.; Laulainen, N.; Iedema, M.; Lefer, B. L.; Anderson, D.; Pernia, D.; Flynn, J. H.

    2010-12-01

    Particulate matters (PM) play important roles in the formation and transformation of ozone. Although photooxidation of volatile organic compounds with respect to ozone formation in the gas phase is well understood, many unknowns still exist in heterogeneous mechanisms that process soot, secondary aerosols (both inorganic and organic), and key radical precursors such as formaldehyde and nitrous acid. Our main objective is to answer two key science questions: 1) will reduction of fine PM reduce ozone formation? 2) What sources of PM are most culpable? Are they from local chemistry or long-range transport? The field data collected in the 2009 Study of Houston Atmospheric Radical Precursors (SHARP) by our group at the Moody Tower consist of 1) real-time photolysis rates of ozone precursors, 2) particle size distributions, 3) organic carbon and elemental carbon, and 4) an archive of single particle samples taken with the Time Resolved Aerosol Collector (TRAC) sampler. The time resolution of the TRAC sampler is 30 minutes for routine measurements, and 15 minutes during some identified “events” (usually in the mid-afternoon) of high ozone and secondary organic or sulfate particle formation. The latter events last typically about an hour. Five ozone exceedance days occurred during the 6 weeks of deployment. Strong correlation between photochemical activities and organic carbon was observed. Initial data analysis indicates that secondary organic aerosol is a major component of the carbonaceous aerosols observed in Houston. Soot, secondary sulfate, seal salt, and mineral dust particles are determined from single particle analysis using scanning electron microscope and transmission electron microcopy coupled with energy dispersive X-ray spectroscopy. Compared with observations in 2000, the mass percentage of organics is higher (60 vs. 30%), and lower for sulfate (20% vs. 32%). On-going data analysis will focus on the composition, sources, and transformation of primary and

  7. How well can we Measure the Vertical Profile of Tropospheric Aerosol Extinction?

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Ferrare, R.; Flynn, C.; Elleman, R.; Covert, D.; Strawa, A.; Welton, E.; Turner, D.; Jonsson, H.; Redemann, J.

    2005-01-01

    The recent Department of Energy Atmospheric Radiation Measurement (ARM) Aerosol Intensive Operations Period (MOP, May 2003) yielded one of the best measurement sets obtained to-date to assess our ability to measure the vertical profile of ambient aerosol extinction sigma(sub ep)(lambda) in the lower troposphere. During one month, a heavily instrumented aircraft with well characterized aerosol sampling ability carrying well proven and new aerosol instrumentation, devoted most of the 60 available flight hours to flying vertical profiles over the heavily instrumented ARM Southern Great Plains (SGP) Climate Research Facility (CRF). This allowed us to compare vertical extinction profiles obtained from 6 different instuments: airborne Sun photometer (AATS-14), airborne nephelometer/absorption photometer, airborne cavity ring-down system, ground-based Raman lidar and 2 ground-based elastic backscatter lidars. We find the in-situ measured sigma(sub ep)(lambda) to be lower than the AATS-14 derived values. Bias differences are 0.002 - 0.004 K/m equivalent to 12-17% in the visible, or 45% in the near-infrared. On the other hand, we find that with respect to AATS-14, the lidar sigma(sub ep)(lambda) are higher. An unnoticed loss of sensitivity of the Raman lidar had occurred leading up to AIOP and we expect better agreement from the recently restored system looking at the collective results from 6 field campaigns conducted since 1996, airborne in situ measurements of sigma(sub ep)(lambda) tend to be biased slightly low (17% at visible wavelengths) when compared to airborne Sun photometer sigma(sub ep)(lambda). On the other hand, sigma(sub ep)(lambda) values derived from lidars tend to have no or positive biases. From the bias differences we conclude that the typical systematic error associated with measuring the tropospheric vertical profile of the ambient aerosol extinction with current state of-the art instrumentation is 15-20% at visible wavelengths and potentially larger in

  8. Statistical Characteristics of Aerosol Extinction Coefficient Profile in East Asia from CALIPSO

    NASA Astrophysics Data System (ADS)

    Sun, Xuejin; Zhou, Junhao; Zhou, Yongbo

    2016-06-01

    Aerosol extinction coefficient profile (ECP) is important in radiative transfer modeling, however, knowledge of ECP in some area has not been clearly recognized. To get a full understanding of statistical characteristics of ECP in three Asian regions: the Mongolian Plateau, the North China Plain and the Yellow Sea, CALIPSO aerosol product in 2012 is processed by conventional statistical methods. Orbit averaged ECP turns out to be mainly exponential and Gaussian patterns. Curve fitting shows that the two ECP patterns account for more than 50 percent of all the samples, especially in the Yellow Sea where the frequency of occurrence even reaches over 80 percent. Parameters determining fitting curves are provided consequently. To be specific, Gaussian pattern is the main ECP distribution in the Mongolian Plateau and the Yellow Sea, and exponential pattern predominates in the North China Plain. Besides, aerosol scale height reaches its maximum in summer and in the Mongolian Plateau. Meanwhile, the uplifting and deposition of dust during transportation are potentially explanations to the occurrence of Gaussian ECP. The results have certain representativeness, and contribute to reducing uncertainties of aerosol model in relevant researches.

  9. Aerosol and ozone changes as forcing for climate evolution between 1850 and 2100

    NASA Astrophysics Data System (ADS)

    Szopa, Sophie; Balkanski, Y.; Schulz, M.; Bekki, S.; Cugnet, D.; Fortems-Cheiney, A.; Turquety, S.; Cozic, A.; Déandreis, C.; Hauglustaine, D.; Idelkadi, A.; Lathière, J.; Lefevre, F.; Marchand, M.; Vuolo, R.; Yan, N.; Dufresne, J.-L.

    2013-05-01

    Global aerosol and ozone distributions and their associated radiative forcings were simulated between 1850 and 2100 following a recent historical emission dataset and under the representative concentration pathways (RCP) for the future. These simulations were used in an Earth System Model to account for the changes in both radiatively and chemically active compounds, when simulating the climate evolution. The past negative stratospheric ozone trends result in a negative climate forcing culminating at -0.15 W m-2 in the 1990s. In the meantime, the tropospheric ozone burden increase generates a positive climate forcing peaking at 0.41 W m-2. The future evolution of ozone strongly depends on the RCP scenario considered. In RCP4.5 and RCP6.0, the evolution of both stratospheric and tropospheric ozone generate relatively weak radiative forcing changes until 2060-2070 followed by a relative 30 % decrease in radiative forcing by 2100. In contrast, RCP8.5 and RCP2.6 model projections exhibit strongly different ozone radiative forcing trajectories. In the RCP2.6 scenario, both effects (stratospheric ozone, a negative forcing, and tropospheric ozone, a positive forcing) decline towards 1950s values while they both get stronger in the RCP8.5 scenario. Over the twentieth century, the evolution of the total aerosol burden is characterized by a strong increase after World War II until the middle of the 1980s followed by a stabilization during the last decade due to the strong decrease in sulfates in OECD countries since the 1970s. The cooling effects reach their maximal values in 1980, with -0.34 and -0.28 W m-2 respectively for direct and indirect total radiative forcings. According to the RCP scenarios, the aerosol content, after peaking around 2010, is projected to decline strongly and monotonically during the twenty-first century for the RCP8.5, 4.5 and 2.6 scenarios. While for RCP6.0 the decline occurs later, after peaking around 2050. As a consequence the relative

  10. A study on the temporal and spatial variability of absorbing aerosols using Total Ozone Mapping Spectrometer and Ozone Monitoring Instrument Aerosol Index data

    NASA Astrophysics Data System (ADS)

    Li, Jing; Carlson, Barbara E.; Lacis, Andrew A.

    2009-05-01

    Absorbing aerosols, especially mineral dust and black carbon, play key roles in climate change by absorbing solar radiation, heating the atmosphere, and contributing to global warming. In this paper, we first examine the consistency of the Aerosol Index (AI) product as measured by the Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI) instruments and then analyze these AI data sets to investigate the temporal and spatial variability of UV absorbing aerosols. In contrast to the trend in aerosol optical depth found in the advanced very high-resolution radiometer data, no obvious long-term trend in absorbing aerosols is observed from the time series of AI records. The comparison between the mean annual cycle in the two data sets shows that the cycles agree very well both globally and regionally, indicating a consistency between the AI products from TOMS and OMI. Varimax rotated Empirical Orthogonal Function (EOF) analysis of detrended, deseasonalized AI data proves to be successful in isolating major dust and biomass burning source regions, as well as dust transport. Finally, we find that large, individual events, such as the Kuwait oil fire and Australian smoke plum, are isolated in individual higher-order principal components.

  11. The Reactive-Diffusive Length of OH and Ozone in Model Organic Aerosols.

    PubMed

    Lee, Lance; Wilson, Kevin

    2016-09-01

    A key step in the heterogeneous oxidation of atmospheric aerosols is the reaction of ozone (O3) and hydroxyl radicals (OH) at the gas-particle interface. The formation of reaction products and free radical intermediates and their spatial distribution inside the particle is a sensitive function of the length over which these oxidants diffuse prior to reaction. The reactive-diffusive length of OH and ozone at organic aerosol interfaces is determined by observing the change in the effective uptake coefficient for size-selected model aerosols comprising a reactive core and a thin nanometer-sized (0-12 nm) organic shell. The core and shell materials are selected so that they are immiscible and adopt an assumed core-shell configuration. The results indicate a reactive-diffusive length of 1.4 nm for hydroxyl (OH) radicals in squalane and 1.0 nm for ozone in squalene. Measurements for a purely diffusive system allow for an estimate for diffusion constant (1.6 × 10(-6) cm(2)/s) of ozone in squalane to be determined. The reactive-diffusive length offers a simple first order estimate of how shielding of aerosols by immiscible layers can alter estimates of oxidative lifetimes of aerosols in the atmosphere. PMID:27509443

  12. Chemical composition of aerosol particles and light extinction apportionment before and during the heating season in Beijing, China

    NASA Astrophysics Data System (ADS)

    Wang, Qingqing; Sun, Yele; Jiang, Qi; Du, Wei; Sun, Chengzhu; Fu, Pingqing; Wang, Zifa

    2015-12-01

    Despite extensive efforts into characterization of the sources and formation mechanisms of severe haze pollution in the megacity of Beijing, the response of aerosol composition and optical properties to coal combustion emissions in the heating season remain poorly understood. Here we conducted a 3 month real-time measurement of submicron aerosol (PM1) composition by an Aerosol Chemical Speciation Monitor and particle light extinction by a Cavity Attenuated Phase Shift extinction monitor in Beijing, China, from 1 October to 31 December 2012. The average (±σ) PM1 concentration was 82.4 (±73.1) µg/m3 during the heating period (HP, 15 November to 31 December), which was nearly 50% higher than that before HP (1 October to 14 November). While nitrate and secondary organic aerosol (SOA) showed relatively small changes, organics, sulfate, and chloride were observed to have significant increases during HP, indicating the dominant impacts of coal combustion sources on these three species. The relative humidity-dependent composition further illustrated an important role of aqueous-phase processing for the sulfate enhancement during HP. We also observed great increases of hydrocarbon-like OA (HOA) and coal combustion OA (CCOA) during HP, which was attributed to higher emissions at lower temperatures and coal combustion emissions, respectively. The relationship between light extinction and chemical composition was investigated using a multiple linear regression model. Our results showed that the largest contributors to particle extinction were ammonium nitrate (32%) and ammonium sulfate (28%) before and during HP, respectively. In addition, the contributions of SOA and primary OA to particle light extinction were quantified. The results showed that the OA extinction was mainly caused by SOA before HP and by SOA and CCOA during HP, yet with small contributions from HOA and cooking aerosol for the entire study period. Our results elucidate substantial changes of aerosol

  13. Infrared extinction spectra of mineral dust aerosol: Single components and complex mixtures

    NASA Astrophysics Data System (ADS)

    Laskina, Olga; Young, Mark A.; Kleiber, Paul D.; Grassian, Vicki H.

    2012-09-01

    Simultaneous Fourier transform infrared (FTIR) extinction spectra and aerosol size distributions have been measured for some components of mineral dust aerosol including feldspars (albite, oligoclase) and diatomaceous earth, as well as more complex authentic dust samples that include Iowa loess and Saharan sand. Spectral simulations for single-component samples, derived from Rayleigh-theory models for characteristic particle shapes, better reproduce the experimental spectra including the peak position and band shape compared to Mie theory. The mineralogy of the authentic dust samples was inferred using analysis of FTIR spectra. This approach allows for analysis of the mineralogy of complex multicomponent dust samples. Extinction spectra for the authentic dust samples were simulated from the derived sample mineralogy using published optical constant data for the individual mineral constituents and assuming an external mixture. Nonspherical particle shape effects were also included in the simulations and were shown to have a significant effect on the results. The results show that the position of the peak and the shape of the band of the IR characteristic features in the 800 to 1400 cm-1 spectral range are not well simulated by Mie theory. The resonance peaks are consistently shifted by more than +40 cm-1 relative to the experimental spectrum in the Mie simulation. Rayleigh model solutions for different particle shapes better predict the peak position and band shape of experimental spectra, even though the Rayleigh condition may not be strictly obeyed in these experiments.

  14. Aerosol optical depth over a remote semi-arid region of South Africa from spectral measurements of the daytime solar extinction and the nighttime stellar extinction

    NASA Astrophysics Data System (ADS)

    Formenti, P.; Winkler, H.; Fourie, P.; Piketh, S.; Makgopa, B.; Helas, G.; Andreae, M. O.

    Spectral daytime aerosol optical depths have been measured at Sutherland, South Africa (32°22'S, 20°48'E), from January 1998 to November 1999. Sutherland is located in the semi-arid Karoo desert, approximately 400-km northeast from Cape Town. The site, remote from major sources of aerosols, hosts the South African Astronomical Observatory (SAAO), where nighttime stellar extinction is being measured. The comparison of daytime and nighttime measurements for the years 1998-1999 makes it possible to validate the astronomical dataset of aerosol optical depth ( τa) dating back to 1991. The 1998 and 1999 annually averaged daytime τa at 500 nm are 0.04±0.04 and 0.06±0.06, respectively. Half-day averages vary between 0.03 and 0.44, with peak values in August-September. This pronounced seasonality is linked to the biomass-burning season in the Southern Hemisphere. Smoke haze layers transported to Sutherland originated primarily on the African landmass at latitudes between 10° and 20°S and passed over Namibia and Angola. On one occasion, aerosols from fires in Brazil transported across the Atlantic Ocean were likely detected. The haze layers reaching Sutherland are therefore at least 2-3 days old. The spectral dependence of the aerosol optical depth for the smoke layers supports the bimodality of the volume size distribution for biomass burning aerosols. The accumulation mode has a volume modal diameter of 0.32 μm, consistent with the hypothesis of aged haze. The stellar measurements (1991-2001) show that, due to the eruption of Mt. Pinatubo, the atmospheric extinction depth at 550 nm in the years 1991-1993 increased by 33% with respect to the average value (0.14±0.03) for the period 1994-2001. Outside the Pinatubo event, extinction is largest in the period 1997-1999.

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

    NASA Technical Reports Server (NTRS)

    Shiotani, Masato; Hasebe, Fumio

    1994-01-01

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

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

    SciTech Connect

    Shiotani, M.; Hasebe, F. |

    1994-07-01

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

  17. Two-dimensional simulation of Pinatubo aerosol and its effect on stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Tie, Xuexi; Brasseur, Guy P.; Briegleb, Bruce; Granier, Claire

    1994-01-01

    This paper presents time-dependent simulations of the response of the stratosphere to the injection into the atmosphere of massive amounts of sulfur during the eruption of Mt. Pinatubo (The Philippines) in June 1991. The study is based on a coupled two-dimensional chemical-dynamical-radiative model to which a microphysical model for sulfate aerosol formation and fate has been added. The study suggests that, during the first year (July 1991 to June 1992) following the volcanic eruption, the observed changes in the ozone amount integrated between 65 deg S and 65 deg N were caused primarily by changes in the meridional circulation (associated with heating by the volcanic cloud in the tropics) and in the photolysis rate of molecules such as ozone (associated with backscattering of light by the cloud). During the second year after the eruption, as the aerosol was dispersed at all latitudes and, in particular, reached the polar region, the largest contribution to ozone reduction resulted from the heterogeneous chemical conversion of N2O5 and ClONO2 on the surface of the aerosol particles. The conversion of the latter compound, and hence the magnitude of the calculated ozone depletion, is highly dependent on the temperature in the lower stratosphere. Despite the fact that the surface area provided by aerosol particles decreased during the second year following the eruption, the calculated ozone depletion remained significant because the conversion of N2O5 is insensitive to the aerosol surface area density for values larger than 1-10 sq microns/cu cm (depending on latitude). The predicted reduction in ozone at 20 km in March during the third year (July 1993 to June 1994) of the model integration is smaller by a factor of 2 than it was during the second year.

  18. Aerosol extinction in a remote continental region of the Iberian Peninsula during summer

    NASA Astrophysics Data System (ADS)

    Elias, Thierry; Silva, Ana Maria; Belo, Nuno; Pereira, Sergio; Formenti, Paola; Helas, Günter; Wagner, Frank

    2006-07-01

    Summer in Évora (38°34'N, 7°54'W), Portugal, is described in terms of aerosol properties of extinction of the solar radiation. We create a data set composed of (1) cloud-screened half-day averaged values of aerosol optical thickness (AOT) measured at 7 wavelengths by both a CIMEL Sun/sky-photometer and a YES shadowband radiometer and (2) half day averaged values of aerosol scattering coefficient (ASC) measured at the surface level at two wavelengths by a TSI nephelometer. Spectral dependence of both AOT and ASC gives the column and the surface Ångström exponents, αC and αS, respectively. Measurements are acquired in both 2002 and 2003 summers. Back trajectories are computed. A statistical study of the data set provides thresholds in AOT and αC for a classification of the days. The classification is applied with success to the case study of the 2003 summer heat wave episode and is generalized to the whole data set. In 23% of the cases, the turbidity in Évora is very low, with AOT441 < 0.12 and AOT873 < 0.04. The air mass origin is the North Atlantic Ocean at 700 and 970 hPa. In 31% of the cases, the turbidity is high. Increase of AOT is due to forest fire emissions, originating in the Iberian Peninsula, with 0.30 < AOT441 < 1.10 and αC > 1.2, and to desert dust plumes transported from North Africa within 72 to 120 hours at 700 hPa, with 0.10 < AOT873 < 1.10 and 0.1 < αC < 1.0. The vertical profile is highly variable, and several cases of aerosol mixing in the column are identified. The duration of the aerosol episode during the 2003 summer heat wave is 16 days, which is exceptionally long.

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  20. Ozone Depletion at Mid-Latitudes: Coupling of Volcanic Aerosols and Temperature Variability to Anthropogenic Chlorine

    NASA Technical Reports Server (NTRS)

    Solomon, S.; Portmann, R. W.; Garcia, R. R.; Randel, W.; Wu, F.; Nagatani, R.; Gleason, J.; Thomason, L.; Poole, L. R.; McCormick, M. P.

    1998-01-01

    Satellite observations of total ozone at 40-60 deg N are presented from a variety of instruments over the time period 1979-1997. These reveal record low values in 1992-3 (after Pinatubo) followed by partial but incomplete recovery. The largest post-Pinatubo reductions and longer-term trends occur in spring, providing a critical test for chemical theories of ozone depletion. The observations are shown to be consistent with current understanding of the chemistry of ozone depletion when changes in reactive chlorine and stratospheric aerosol abundances are considered along with estimates of wave-driven fluctuations in stratospheric temperatures derived from global temperature analyses. Temperature fluctuations are shown to make significant contributions to model calculated northern mid-latitude ozone depletion due to heterogeneous chlorine activation on liquid sulfate aerosols at temperatures near 200-210 K (depending upon water vapor pressure), particularly after major volcanic eruptions. Future mid-latitude ozone recovery will hence depend not only on chlorine recovery but also on temperature trends and/or variability, volcanic activity, and any trends in stratospheric sulfate aerosol.

  1. Effect of fatty acid coatings on ozone uptake to deliquesced KI/NaCl aerosol particles

    NASA Astrophysics Data System (ADS)

    Ammann, M.; Rouvière, A.

    2009-12-01

    Phase transfer kinetics of gas phase oxidants may limit oxidative aging of aerosol particles. The aim of this work is to study the role of amphiphilic organic aerosol constituents on the kinetics of phase transfer of gaseous species to the bulk aqueous phase. The effect of (C9-C20) fatty acid surfactants on the phase transfer of ozone to deliquesced potassium iodide and sodium chloride have been investigated. Some other experiments of ozone uptake have been performed with different mixtures and proportions of fatty acids. The kinetic experiments were performed in an aerosol flow tube at room temperature and atmospheric pressure. To obtain deliquesced inorganic particles, the relative humidity was adjusted in the range of 75% to 80%. It is shown that the fatty acids in monolayer quantities may substantially inhibit the phase transfer of ozone to deliquesced particles. The results showed that especially the C15-C20 limit the mass transfer of ozone to the aqueous phase, whereby the magnitude of this effect was following the monolayer properties of the fatty acids. It was also possible to determine a resistance of such films to the transfer of ozone to the bulk phase.

  2. EFFECT OF OZONE EXPOSURE ON THE DISPERSION OF INHALED AEROSOL BOLUSES IN HEALTHY HUMAN SUBJECTS

    EPA Science Inventory

    Acute exposure of humans to low levels of ozone are known to cause decreases FVC and increases sRaw. hese alterations in lung function do not, however, elucidate the potential for acute small airways responses. n this study we employed a test of aerosol dispersion to examine the ...

  3. MORPHOLOGICAL EFFECTS OF PROLONGED EXPOSURE TO OZONE AND SULFURIC ACID AEROSOL ON THE RAT LUNG

    EPA Science Inventory

    The purpose of this study was to determine the pulmonary effects of a combination of ozone (0.5 ppm) and sulfuric acid aerosol (1 mg/cu. m.) and to assess the possibility of interactive effects. Groups of Sprague-Dawley rats were continously exposed to the pollutants, either indi...

  4. Characterization and source apportionment of aerosol light extinction with a coupled model of CMB-IMPROVE in Hangzhou, Yangtze River Delta of China

    NASA Astrophysics Data System (ADS)

    Wang, Jiao; Zhang, Yu-fen; Feng, Yin-chang; Zheng, Xian-jue; Jiao, Li; Hong, Sheng-mao; Shen, Jian-dong; Zhu, Tan; Ding, Jing; Zhang, Qi

    2016-09-01

    To investigate the characteristics and sources of aerosol light extinction in the Yangtze River Delta of China, a campaign was carried out in Hangzhou from December 2013 to November 2014. Hourly data for air pollutants including PM2.5, SO2, NO2, O3 and CO, and aerosol optical properties including aerosol scattering coefficient and aerosol absorbing coefficient was obtained in the environmental air quality automatic monitoring station. Meteorological parameters were measured synchronously in the automated meteorology monitoring station. Additionally, around seven sets of ambient PM2.5 samples per month were collected and analyzed during the campaign. The annual mean aerosol scattering coefficient, aerosol absorbing coefficient and aerosol single scattering albedo measured in this study was 514 ± 284 Mm- 1, 35 ± 20 Mm- 1 and 94% respectively. The aerosol extinction coefficient reconstructed using the modified IMPROVE (Interagency Monitoring of Protected Visual Environment) formula was compared to the measured extinction coefficient. Better correlations could be found between the measured and reconstructed extinction coefficient when RH was under 90%. A coupled model of CMB (chemical mass balance) and modified IMPROVE was used to apportion the sources of aerosol light extinction in Hangzhou. Vehicle exhaust, secondary nitrate and secondary sulfate were identified as the most significant sources for aerosol light extinction, accounted for 30.2%, 24.1% and 15.8% respectively.

  5. Correction of DIAL Stratospheric Ozone Measurements in the Presence of Pinatubo Aerosols

    NASA Technical Reports Server (NTRS)

    Fenn, Marta A.; Ismail, Syed; Browell, Edward V.; Butler, Carolyn F.

    1992-01-01

    NASA Langley's airborne lidar system measured aerosol and ozone distributions in the stratosphere from Jan. - Mar. 1992 as part of the Airborne Arctic Stratospheric expedition (AASE-2). The eruption of Mount Pinatubo in Jun. 1991 has increased the aerosol burden of the stratosphere and thereby increased the importance of applying an aerosol correction to the ozone measurements. The correction relies on a Bernoulli solution to derive a backscatter correction to the differential absorption lidar (DIAL) returns at two wavelengths in the ultraviolet spectral region (lambda(sub on) = 301.5 nm, lambda(sub off) = 310.87 nm) as described in earlier works. This paper discusses how the parameters for the correction were optimized for application to the AASE-2 data set.

  6. Autonomous Ozone and Aerosol LIDAR Profiling of the Troposphere: A Synergistic Approach

    NASA Astrophysics Data System (ADS)

    Strawbridge, K. B.

    2015-12-01

    LIDAR technology is an excellent tool to probe the complex vertical structure of the atmosphere at high spatial and temporal resolution. This provides the critical vertical context for the interpretation of ground-based chemistry measurements, airborne measurements and model/satellite verification and validation. In recent years, Environment Canada has designed several autonomous aerosol LIDAR systems for deployment across several regions of Canada. The current system builds on the successes of these autonomous LIDARS but using a synergistic approach by combining tropospheric ozone DIAL (Differential Absorption LIDAR) technology with simultaneous 3+2+1 aerosol LIDAR measurements. It operates 24 hours a day, seven days a week except during precipitation events. The system is operated remotely and the data are updated every hour to a website to allow near real-time capability. A few case studies are shown emphasizing the synergistic approach of coupling ozone and aerosol profiles to better understand air quality impacts on local and regional scales.

  7. The CU Airborne MAX-DOAS instrument: vertical profiling of aerosol extinction and trace gases

    NASA Astrophysics Data System (ADS)

    Baidar, S.; Oetjen, H.; Coburn, S.; Dix, B.; Ortega, I.; Sinreich, R.; Volkamer, R.

    2013-03-01

    The University of Colorado Airborne Multi-Axis Differential Optical Absorption Spectroscopy (CU AMAX-DOAS) instrument uses solar stray light to detect and quantify multiple trace gases, including nitrogen dioxide (NO2), glyoxal (CHOCHO), formaldehyde (HCHO), water vapor (H2O), nitrous acid (HONO), iodine monoxide (IO), bromine monoxide (BrO), and oxygen dimers (O4) at multiple wavelengths (absorption bands at 360, 477, 577, 632 nm) simultaneously in the open atmosphere. The instrument is unique as it (1) features a motion compensation system that decouples the telescope field of view from aircraft movements in real time (<0.35° accuracy), and (2) includes measurements of solar stray light photons from nadir, zenith, and multiple elevation angles forward and below the plane by the same spectrometer/detector system. Sets of solar stray light spectra collected from nadir to zenith scans provide some vertical profile information within 2 km above and below the aircraft altitude, and the vertical column density (VCD) below the aircraft is measured in nadir view. Maximum information about vertical profiles is derived simultaneously for trace gas concentrations and aerosol extinction coefficients over similar spatial scales and with a vertical resolution of typically 250 m during aircraft ascent/descent. The instrument is described, and data from flights over California during the CalNex (California Research at the Nexus of Air Quality and Climate Change) and CARES (Carbonaceous Aerosols and Radiative Effects Study) air quality field campaigns is presented. Horizontal distributions of NO2 VCD (below the aircraft) maps are sampled with typically 1 km resolution, and show good agreement with two ground-based MAX-DOAS instruments (slope = 0.95 ± 0.09, R2 = 0.86). As a case study vertical profiles of NO2, CHOCHO, HCHO, and H2O concentrations and aerosol extinction coefficients, ɛ, at 477 nm calculated from O4 measurements from a low approach at Brackett airfield inside the

  8. Extinction-to-Backscatter Ratios of Lofted Aerosol Layers Observed During the First Three Months of CALIPSO Measurements

    NASA Technical Reports Server (NTRS)

    Omar, Ali H.; Vaughan, Mark A.; Liu, Zhaoyan; Hu, Yongxiang; Reagan, John A.; Winker, David M.

    2007-01-01

    Case studies from the first three months of the Cloud and Aerosol Lidar and Infrared Pathfinder Spaceborne Observations (CALIPSO) measurements of lofted aerosol layers are analyzed using transmittance [Young, 1995] and two-wavelength algorithms [Vaughan et al., 2004] to determine the aerosol extinction-to-backscatter ratios at 532 and 1064 nm. The transmittance method requires clear air below the layer so that the transmittance through the layer can be determined. Suitable scenes are selected from the browse images and clear air below features is identified by low 532 nm backscatter signal and confirmed by low depolarization and color ratios. The transmittance and two-wavelength techniques are applied to a number of lofted layers and the extinction-to-backscatter ratios are compared with values obtained from the CALIPSO aerosol models [Omar et al., 2004]. The results obtained from these studies are used to adjust the aerosol models and develop observations based extinction-to-backscatter ratio look-up tables and phase functions. Values obtained by these techniques are compared to Sa determinations using other independent methods with a goal of developing probability distribution functions of aerosol type-specific extinction to backscatter ratios. In particular, the results are compared to values determined directly by the High Spectral Resolution Lidar (HSRL) during the CALIPSO CloudSat Validation Experiments (CCVEX) and Sa determined by the application of the two-wavelength lidar Constrained Ratio Aerosol Model-fit (CRAM) retrieval approach [Cattrall et al., 2005; Reagan et al., 2004] to the HSRL data. The results are also compared to values derived using the empirical relationship between the multiple-scattering fraction and the linear depolarization ratio by using Monte Carlo simulations of water clouds [Hu et al., 2006].

  9. Estimated SAGE II ozone mixing ratios in early 1993 and comparisons with Stratospheric Photochemistry, Aerosols and Dynamic Expedition measurements

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Veiga, R. E.; Poole, L. R.; Zawodny, J. M.; Proffitt, M. H.

    1994-01-01

    An empirical time-series model for estimating ozone mixing ratios based on Stratospheric Aerosols and Gas Experiment II (SAGE II) monthly mean ozone data for the period October 1984 through June 1991 has been developed. The modeling results for ozone mixing ratios in the 10- to 30- km region in early months of 1993 are presented. In situ ozone profiles obtained by a dual-beam UV-absorption ozone photometer during the Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE) campaign, May 1-14, 1993, are compared with the model results. With the exception of two profiles at altitudes below 16 km, ozone mixing ratios derived by the model and measured by the ozone photometer are in relatively good agreement within their individual uncertainties. The identified discrepancies in the two profiles are discussed.

  10. Observation of ozone and aerosols in the Antarctic ozone hole of 1991 under the Polar Patrol Balloon (PPB) Project. Preliminary result

    NASA Technical Reports Server (NTRS)

    Hayashi, Masahiko; Murata, Isao; Iwasaka, Yasunobu; Kondo, Yutaka; Kanzawa, Hiroshi

    1994-01-01

    We present preliminary results for the PPB (Polar Patrol Balloon) experiment. The balloon was launched at 07:55 UT on 23 September and dropped at 21 UT on 28 September 1991. During the period, ozone and aerosol concentrations were measured correspondingly along the track. During the Lagrangian type observation, drastic change of ozone concentration in 'same air mass' and positive correlation between ozone concentration and sulfate aerosol amount were obtained at the level within 80-78 hPa. During the descent motion at 80 deg S active PSC's (type-1 and -2) were observed from 200 hPa to 80 hPa.

  11. In situ vertical profiles of aerosol extinction, mass, and composition over the southeast United States during SENEX and SEAC4RS: observations of a modest aerosol enhancement aloft

    NASA Astrophysics Data System (ADS)

    Wagner, N. L.; Brock, C. A.; Angevine, W. M.; Beyersdorf, A.; Campuzano-Jost, P.; Day, D. A.; de Gouw, J. A.; Diskin, G. S.; Gordon, T. D.; Graus, M. G.; Huey, G.; Jimenez, J. L.; Lack, D. A.; Liao, J.; Liu, X.; Markovic, M. Z.; Middlebrook, A. M.; Mikoviny, T.; Peischl, J.; Perring, A. E.; Richardson, M. S.; Ryerson, T. B.; Schwarz, J. P.; Warneke, C.; Welti, A.; Wisthaler, A.; Ziemba, L. D.; Murphy, D. M.

    2015-02-01

    Vertical profiles of submicron aerosol over the southeastern United States (SEUS) during the summertime from in situ aircraft-based measurements were used to construct aggregate profiles of chemical, microphysical, and optical properties. Shallow cumulus convection was observed during many profiles. These conditions enhance vertical transport of trace gases and aerosol and create a cloudy transition layer on top of the sub-cloud mixed layer. The trace gas and aerosol concentrations in the transition layer were modeled as a mixture with contributions from the mixed layer below and the free troposphere above. The amount of vertical mixing, or entrainment of air from the free troposphere, was quantified using the observed mixing ratio of carbon monoxide (CO). Although the median aerosol mass, extinction, and volume decreased with altitude in the transition layer, they were ~10% larger than expected from vertical mixing alone. This enhancement was likely due to secondary aerosol formation in the transition layer. Although the transition layer enhancements of the particulate sulfate and organic aerosol (OA) were both similar in magnitude, only the enhancement of sulfate was statistically significant. The column integrated extinction, or aerosol optical depth (AOD), was calculated for each individual profile, and the transition layer enhancement of extinction typically contributed less than 10% to the total AOD. Our measurements and analysis were motivated by two recent studies that have hypothesized an enhanced layer of secondary organic aerosol (SOA) aloft to explain the summertime enhancement of AOD (2-3 times greater than winter) over the southeastern United States. In contrast to this hypothesis, the modest enhancement we observed in the transition layer was not dominated by OA and was not a large fraction of the summertime AOD.

  12. The Global Ozone and Aerosol Profiles and Aerosol Hygroscopic Effect and Absorption Optical Depth (GOA2HEAD) Network Initiative

    NASA Astrophysics Data System (ADS)

    Gao, R. S.; Elkins, J. W.; Frost, G. J.; McComiskey, A. C.; Murphy, D. M.; Ogren, J. A.; Petropavlovskikh, I. V.; Rosenlof, K. H.

    2014-12-01

    Inverse modeling using measurements of ozone (O3) and aerosol is a powerful tool for deriving pollutant emissions. Because they have relatively long lifetimes, O3 and aerosol are transported over large distances. Frequent and globally spaced vertical profiles rather than ground-based measurements alone are therefore highly desired. Three requirements necessary for a successful global monitoring program are: Low equipment cost, low operation cost, and reliable measurements of known uncertainty. Conventional profiling using aircraft provides excellent data, but is cost prohibitive on a large scale. Here we describe a new platform and instruments meeting all three global monitoring requirements. The platform consists of a small balloon and an auto-homing glider. The glider is released from the balloon at about 5 km altitude, returning the light instrument package to the launch location, and allowing for consistent recovery of the payload. Atmospheric profiling can be performed either during ascent or descent (or both) depending on measurement requirements. We will present the specifications for two instrument packages currently under development. The first measures O3, RH, p, T, dry aerosol particle number and size distribution, and aerosol optical depth. The second measures dry aerosol particle number and size distribution, and aerosol absorption coefficient. Other potential instrument packages and the desired spatial/temporal resolution for the GOA2HEAD monitoring initiative will also be discussed.

  13. On the accuracy of stratospheric aerosol extinction derived from in situ size distribution measurements and surface area density derived from remote SAGE II and HALOE extinction measurements

    NASA Astrophysics Data System (ADS)

    Kovilakam, Mahesh; Deshler, Terry

    2015-08-01

    In situ stratospheric aerosol measurements, from University of Wyoming optical particle counters (OPCs), are compared with Stratospheric Aerosol Gas Experiment (SAGE) II (versions 6.2 and 7.0) and Halogen Occultation Experiment (HALOE) satellite measurements to investigate differences between SAGE II/HALOE-measured extinction and derived surface area and OPC-derived extinction and surface area. Coincident OPC and SAGE II measurements are compared for a volcanic (1991-1996) and nonvolcanic (1997-2005) period. OPC calculated extinctions agree with SAGE II measurements, within instrumental uncertainty, during the volcanic period, but have been a factor of 2 low during the nonvolcanic period. Three systematic errors associated with the OPC measurements, anisokineticity, inlet particle evaporation, and counting efficiency, were investigated. An overestimation of the OPC counting efficiency is found to be the major source of systematic error. With this correction OPC calculated extinction increases by 15-30% (30-50%) for the volcanic (nonvolcanic) measurements. These changes significantly improve the comparison with SAGE II and HALOE extinctions in the nonvolcanic cases but slightly degrade the agreement in the volcanic period. These corrections have impacts on OPC-derived surface area density, exacerbating the poor agreement between OPC and SAGE II (version 6.2) surface areas. This disparity is reconciled with SAGE II version 7.0 surface areas. For both the volcanic and nonvolcanic cases these changes in OPC counting efficiency and in the operational SAGE II surface area algorithm leave the derived surface areas from both platforms in significantly better agreement and within the ± 40% precision of the OPC moment calculations.

  14. On the accuracy of stratospheric aerosol extinction derived from in situ size distribution measurements and surface area density derived from remote SAGE II and HALOE extinction measurements

    DOE PAGESBeta

    Kovilakam, Mahesh; Deshler, Terry

    2015-08-26

    In situ stratospheric aerosol measurements, from University of Wyoming optical particle counters (OPCs), are compared with Stratospheric Aerosol Gas Experiment (SAGE) II (versions 6.2 and 7.0) and Halogen Occultation Experiment (HALOE) satellite measurements to investigate differences between SAGE II/HALOE-measured extinction and derived surface area and OPC-derived extinction and surface area. Coincident OPC and SAGE II measurements are compared for a volcanic (1991-1996) and nonvolcanic (1997 2005) period. OPC calculated extinctions agree with SAGE II measurements, within instrumental uncertainty, during the volcanic period, but have been a factor of 2 low during the nonvolcanic period. Three systematic errors associated with themore » OPC measurements, anisokineticity, inlet particle evaporation, and counting efficiency, were investigated. An overestimation of the OPC counting efficiency is found to be the major source of systematic error. With this correction OPC calculated extinction increases by 15 30% (30 50%) for the volcanic (nonvolcanic) measurements. These changes significantly improve the comparison with SAGE II and HALOE extinctions in the nonvolcanic cases but slightly degrade the agreement in the volcanic period. These corrections have impacts on OPC-derived surface area density, exacerbating the poor agreement between OPC and SAGE II (version 6.2) surface areas. This disparity is reconciled with SAGE II version 7.0 surface areas. For both the volcanic and nonvolcanic cases these changes in OPC counting efficiency and in the operational SAGE II surface area algorithm leave the derived surface areas from both platforms in significantly better agreement and within the 40% precision of the OPC moment calculations.« less

  15. On the accuracy of stratospheric aerosol extinction derived from in situ size distribution measurements and surface area density derived from remote SAGE II and HALOE extinction measurements

    SciTech Connect

    Kovilakam, Mahesh; Deshler, Terry

    2015-08-26

    In situ stratospheric aerosol measurements, from University of Wyoming optical particle counters (OPCs), are compared with Stratospheric Aerosol Gas Experiment (SAGE) II (versions 6.2 and 7.0) and Halogen Occultation Experiment (HALOE) satellite measurements to investigate differences between SAGE II/HALOE-measured extinction and derived surface area and OPC-derived extinction and surface area. Coincident OPC and SAGE II measurements are compared for a volcanic (1991-1996) and nonvolcanic (1997 2005) period. OPC calculated extinctions agree with SAGE II measurements, within instrumental uncertainty, during the volcanic period, but have been a factor of 2 low during the nonvolcanic period. Three systematic errors associated with the OPC measurements, anisokineticity, inlet particle evaporation, and counting efficiency, were investigated. An overestimation of the OPC counting efficiency is found to be the major source of systematic error. With this correction OPC calculated extinction increases by 15 30% (30 50%) for the volcanic (nonvolcanic) measurements. These changes significantly improve the comparison with SAGE II and HALOE extinctions in the nonvolcanic cases but slightly degrade the agreement in the volcanic period. These corrections have impacts on OPC-derived surface area density, exacerbating the poor agreement between OPC and SAGE II (version 6.2) surface areas. This disparity is reconciled with SAGE II version 7.0 surface areas. For both the volcanic and nonvolcanic cases these changes in OPC counting efficiency and in the operational SAGE II surface area algorithm leave the derived surface areas from both platforms in significantly better agreement and within the 40% precision of the OPC moment calculations.

  16. Secondary organic aerosol formation from ozone reactions with single terpenoids and terpenoid mixtures

    NASA Astrophysics Data System (ADS)

    Waring, Michael S.; Wells, J. Raymond; Siegel, Jeffrey A.

    2011-08-01

    Ozone reacts with indoor-emitted terpenoids to form secondary organic aerosol (SOA). Most SOA research has focused on ozone reactions with single terpenoids or with consumer products, and this paper reports the results from an investigation of SOA formation from ozone reactions with both single terpenoids and mixtures of D-limonene, α-pinene, and α-terpineol. Transient experiments were conducted at low (25 ppb) and high (100 ppb) initial concentrations of ozone. The three terpenoids were tested singly and in combinations in a manner that controlled for their different reaction rates with ozone. The SOA formation was assessed by examining the evolution in time of the resulting number size-distributions and estimates of the mass concentrations. The results suggest that at higher ozone and terpenoid concentrations, SOA number formation follows a linear trend as a function of the initial rate of reaction. This finding was valid for both single terpenoids and mixtures. Generally speaking, higher ozone and terpenoid concentrations also led to larger geometric mean diameters and smaller geometric standard deviations of fitted lognormal distributions of the formed SOA. By assuming a density, mass concentrations were also assessed and did not follow as consistent of a trend. At low ozone concentration conditions, reactions with only D-limonene yielded the largest number concentrations of any experiment, even more than experiments with mixtures containing D-limonene and much higher overall terpenoid concentrations. This finding was not seen for high ozone concentrations. These experiments demonstrate quantifiable trends for SOA forming reactions of ozone and mixtures, and this work provides a framework for expanding these results to more complex mixtures and consumer products.

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

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  18. Impacts of a massive release of methane and hydrogen sulfide on oxygen and ozone during the late Permian mass extinction

    NASA Astrophysics Data System (ADS)

    Kaiho, Kunio; Koga, Seizi

    2013-08-01

    The largest mass extinction of animals and plants in both the ocean and on land occurred in the late Permian (252 Ma), largely coinciding with the largest flood basalt volcanism event in Siberia and an oceanic anoxic/euxinic event. We investigated the impacts of a massive release of methane (CH4) from the Siberian igneous province and the ocean and/or hydrogen sulfide (H2S) from the euxinic ocean on oxygen and ozone using photochemical model calculations. Our calculations indicated that an approximate of 14% decrease in atmospheric O2 levels would have occurred in the case of a large combined CH4 and H2S flux to the atmosphere, whereas an approximate of 8 to 10% decrease would have occurred from the CH4 flux and oxidation of all H2S in the ocean. The slight decrease in atmospheric O2 levels may have contributed to the extinction event. We demonstrate for the first time that a massive release of CH4 from the Siberian igneous province and a coincident massive release of CH4 and H2S did not cause ozone collapse. A collapse of stratospheric ozone leading to an increase in UV is not supported by the maximum model input levels for CH4 and H2S. These conclusions on O2 and O3 are correspondent to every H2S release percentages from the ocean to the atmosphere.

  19. Lidar Measurements of Stratospheric Ozone, Aerosols and Temperature during the SAUNA Campaign at Sodankyla, Finland

    NASA Technical Reports Server (NTRS)

    McGee, T.; Twigg, L.; Sumnicht, G.; McPeters, R.; Bojkov, B.; Kivi, R.

    2008-01-01

    The Sodankyla Total Column Ozone Intercomparison (SAUNA) campaign took place at the Finnish Meteorological Institute Arctic Research Center (FMI-ARC) at Sodankyla, Finland (67.37 N) in two separate phases during early spring 2006, and winter 2007. These campaigns has several goals: to determine and improve the accuracy of total column ozone measurements during periods of low solar zenith angle and high total column ozone; to determine the effect of ozone profile shape on the total column retrieval; and to make validate satellite ozone measurements under these same conditions. The GSFC Stratospheric Ozone Lidar (STROZ), which makes profile measurements of ozone temperature, aerosols and water vapor participated in both phases of the campaign. During the deployments, more than 30 profile measurements were made by the lidar instrument, along with Dobson, Brewer, DOAS, ozonesonde, and satellite measurements. The presentation will concentrate on STROZ lidar results from the second phase of the campaign and comparisons with other instruments will be discussed. This will include both ground-based and satellite comparisons.

  20. MODELING THE EFFECT OF CHLORINE EMISSIONS ON ATMOSPHERIC OZONE AND SECONDARY ORGANIC AEROSOL CONCENTRATIONS ACROSS THE UNITED STATES

    EPA Science Inventory

    This paper presents the modeled effects of natural and anthropogenic chlorine emissions on the atmospheric concentrations of ozone and secondary organic aerosol across the United States. The model calculations include anthropogenic molecular chlorine emissions, anthropogenic hypo...

  1. The effect of ozone exposure on the dispersion of inhaled aerosol boluses in healthy human subjects

    SciTech Connect

    Keefe, M.J.; Bennett, W.D.; DeWitt, P.; Seal, E.; Strong, A.A.; Gerrity, T.R. )

    1991-07-01

    Acute exposure of humans to low levels of ozone are known to cause decreases in FVC and increases in SRaw. These alterations in lung function do not, however, elucidate the potential for acute small airway responses. In this study we employed a test of aerosol dispersion to examine the potential effects of ozone on small airways in humans. Twenty-two healthy nonsmoking male volunteers were exposed to 0.4 ppm ozone for 1 h while exercising at 20 L/min/m2 body surface area. Before and immediately after exposure, tests of spirometry (FVC, FEV1, and FEF25-75) and plethysmography (Raw and SRaw) were performed. Subjects also performed an aerosol dispersion test before and after exposure. Each test involved a subject inhaling five to seven breaths of a 300-ml bolus of a 0.5 micron triphenyl phosphate aerosol injected into a 2-L tidal volume. The bolus was injected into the tidal breath at three different depths: at Depth A the bolus was injected after 1.6 L of clean air were inhaled from FRC, at Depth B after 1.2 L, and at Depth C after 1.2 L but with inhalation beginning from RV. The primary measure of bolus dispersion was the expired half-width (HW). Secondary measures were the ratio (expressed as percent) of peak exhaled aerosol concentration to peak inhaled concentration (PR), shift in the median bolus volume between inspiration and expiration (VS), and percent of total aerosol recovered (RC). Changes in pulmonary function after ozone exposure were consistent with previous findings.

  2. A new high spectral resolution lidar technique for direct retrievals of cloud and aerosol extinction

    NASA Astrophysics Data System (ADS)

    Yorks, J. E.; McGill, M. J.; Hlavka, D. L.

    2014-12-01

    The Airborne Cloud-Aerosol Transport System (ACATS) is a Doppler lidar system and high spectral resolution lidar (HSRL) recently developed at NASA Goddard Space Flight Center (GSFC). ACATS passes the returned atmospheric backscatter through a single etalon and divides the transmitted signal into several channels (wavelength intervals), which are measured simultaneously and independently (Figure 1). Both the particulate and molecular scattered signal can be directly and unambiguously measured, allowing for direct retrievals of particle extinction. The broad Rayleigh-scattered spectrum is imaged as a nearly flat background, illustrated in Figure 1c. The integral of the particulate backscattered spectrum is analogous to the aerosol measurement from the typical absorption filter HSRL technique in that the molecular and particulate backscatter components can be separated (Figure 1c and 1d). The main difference between HSRL systems that use the iodine filter technique and the multichannel etalon technique used in the ACATS instrument is that the latter directly measures the spectral broadening of the particulate backscatter using the etalon to filter out all backscattered light with the exception of a narrow wavelength interval (1.5 picometers for ACATS) that contains the particulate spectrum (grey, Figure 1a). This study outlines the method and retrieval algorithms for ACATS data products, focusing on the HSRL derived cloud and aerosol properties. While previous ground-based multi-channel etalon systems have been built and operated for wind retrievals, there has been no airborne demonstration of the technique and the method has not been used to derive HSRL cloud and aerosol properties. ACATS has flown on the NASA ER-2 during flights over Alaska in July 2014 and as part of the Wallops Airborne Vegetation Experiment (WAVE) in September 2012. This study will focus on the HSRL aspect of the ACATS instrument, since the method and retrieval algorithms have direct application

  3. Modeling study on seasonal variation in aerosol extinction properties over China.

    PubMed

    Gao, Yi; Zhang, Meigen

    2014-01-01

    To investigate the seasonal variation of aerosol optical depth (AOD), extinction coefficient (EXT), single scattering albedo (SSA) and the decomposed impacts from sulfate (SO4(2-)) and black carbon (BC) over China, numerical experiments are conducted from November 2007 to December 2008 by using WRF-Chem. Comparison of model results with measurements shows that model can reproduce the spatial distribution and seasonal variation of AOD and SSA. Over south China, AOD is largest in spring (0.6-1.2) and lowest in summer (0.2-0.6). Over north, northeast and east China, AOD is highest in summer while lowest in winter. The high value of EXT under 850 hPa which is the reflection of low visibility ranges from 0.4-0.8 km(-1) and the high value area shifts to north during winter, spring and summer, then back to south in autumn. SSA is 0.92-0.94 in winter and 0.94-0.96 for the other three seasons because of highest BC concentration in winter over south China. Over east China, SSA is highest (0.92-0.96) in summer, and 0.88-0.92 during winter, spring and autumn as the concentration of scattering aerosol is highest while BC concentration is lowest in summer over this region. Over north China, SSA is highest (0.9-0.94) in summer and lowest (0.82-0.86) in winter due to the significant variation of aerosol concentration. The SO4(2-) induced EXT increases about 5%-55% and the impacts of BC on EXT is much smaller (2%-10%). The SO4(2-)-induced increase in SSA is 0.01-0.08 and the BC-induced SSA decreases 0.02-0.18. PMID:24649695

  4. Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia

    DOE PAGESBeta

    Feng, Y.; Kotamarthi, V. R.; Coulter, R.; Zhao, C.; Cadeddu, M.

    2016-01-18

    In this study, aerosol radiative effects and thermodynamic responses over South Asia are examined with the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of aerosol optical depths (AODs) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in northern India. The WRF-Chem model is found to heavily underestimate the AOD during the simulated pre-monsoon month and about 83 % of the model's low bias is due to aerosol extinctions below ~2km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AOD andmore » extinction profiles averaged over South Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same AOD and extinction profiles, the two runs produce significantly different radiative effects over land and oceans. On the regional mean basis, Case I generates 48 % more heating in the atmosphere and 21 % more dimming at the surface than Case II. Case I also produces stronger cooling responses over the land from the longwave radiation adjustment and boundary layer mixing. These rapid adjustments offset the stronger radiative heating in Case I and lead to an overall lower-troposphere cooling up to –0.7 K day−1, which is smaller than that in Case II. Over the ocean, direct radiative effects dominate the heating rate changes in the lower atmosphere lacking such surface and lower atmosphere adjustments due to fixed sea surface temperature, and the strongest atmospheric warming is obtained in Case I. Consequently, atmospheric dynamics (boundary layer heights and meridional circulation) and thermodynamic processes (water vapor and cloudiness) are

  5. Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia

    NASA Astrophysics Data System (ADS)

    Feng, Y.; Kotamarthi, V. R.; Coulter, R.; Zhao, C.; Cadeddu, M.

    2016-01-01

    Aerosol radiative effects and thermodynamic responses over South Asia are examined with the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of aerosol optical depths (AODs) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in northern India. The WRF-Chem model is found to heavily underestimate the AOD during the simulated pre-monsoon month and about 83 % of the model's low bias is due to aerosol extinctions below ˜ 2 km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AOD and extinction profiles averaged over South Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same AOD and extinction profiles, the two runs produce significantly different radiative effects over land and oceans. On the regional mean basis, Case I generates 48 % more heating in the atmosphere and 21 % more dimming at the surface than Case II. Case I also produces stronger cooling responses over the land from the longwave radiation adjustment and boundary layer mixing. These rapid adjustments offset the stronger radiative heating in Case I and lead to an overall lower-troposphere cooling up to -0.7 K day-1, which is smaller than that in Case II. Over the ocean, direct radiative effects dominate the heating rate changes in the lower atmosphere lacking such surface and lower atmosphere adjustments due to fixed sea surface temperature, and the strongest atmospheric warming is obtained in Case I. Consequently, atmospheric dynamics (boundary layer heights and meridional circulation) and thermodynamic processes (water vapor and cloudiness) are shown to respond differently

  6. Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia

    SciTech Connect

    Feng, Y.; Kotamarthi, V. R.; Coulter, R.; Zhao, C.; Cadeddu, M.

    2015-06-19

    Aerosol radiative effects and thermodynamic responses over South Asia are examined with a version of the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of Aerosol Optical Depth (AOD) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in the northern India. The WRF-Chem model is found to underestimate the AOD during the simulated pre-monsoon month and about 83 % of the model low-bias is due to aerosol extinctions below ~2 km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AOD and extinction profiles averaged over South Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same AOD and extinction profiles, the two runs produce significantly different radiative effects over land and oceans. On the regional mean basis, Case I generates 48 % more heating in the atmosphere and 21 % more dimming at the surface than Case II. Case I also produces stronger cooling responses over the land from the longwave radiation adjustment and boundary layer mixing. These rapid adjustments offset the stronger radiative heating in Case I and lead to an overall lower-troposphere cooling up to -0.7 K day−1, which is smaller than that in Case II. Over the ocean, direct radiative effects dominate the heating rate changes in the lower atmosphere lacking such surface and lower atmosphere adjustments due to fixed sea surface temperature, and the strongest atmospheric warming is obtained in Case I. Consequently, atmospheric dynamics (boundary layer heights and meridional circulation) and thermodynamic processes (water vapor and cloudiness) are shown to respond

  7. Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia

    DOE PAGESBeta

    Feng, Y.; Kotamarthi, V. R.; Coulter, R.; Zhao, C.; Cadeddu, M.

    2016-01-18

    Aerosol radiative effects and thermodynamic responses over South Asia are examined with the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of aerosol optical depths (AODs) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in northern India. The WRF-Chem model is found to heavily underestimate the AOD during the simulated pre-monsoon month and about 83 % of the model's low bias is due to aerosol extinctions below  ∼  2 km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AOD and extinction profiles averaged over Southmore » Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same AOD and extinction profiles, the two runs produce significantly different radiative effects over land and oceans. On the regional mean basis, Case I generates 48 % more heating in the atmosphere and 21 % more dimming at the surface than Case II. Case I also produces stronger cooling responses over the land from the longwave radiation adjustment and boundary layer mixing. These rapid adjustments offset the stronger radiative heating in Case I and lead to an overall lower-troposphere cooling up to −0.7 K day−1, which is smaller than that in Case II. Over the ocean, direct radiative effects dominate the heating rate changes in the lower atmosphere lacking such surface and lower atmosphere adjustments due to fixed sea surface temperature, and the strongest atmospheric warming is obtained in Case I. Consequently, atmospheric dynamics (boundary layer heights and meridional circulation) and thermodynamic processes (water vapor and

  8. Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia

    DOE PAGESBeta

    Feng, Y.; Kotamarthi, V. R.; Coulter, R.; Zhao, C.; Cadeddu, M.

    2015-06-19

    Aerosol radiative effects and thermodynamic responses over South Asia are examined with a version of the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of Aerosol Optical Depth (AOD) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in the northern India. The WRF-Chem model is found to underestimate the AOD during the simulated pre-monsoon month and about 83 % of the model low-bias is due to aerosol extinctions below ~2 km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AODmore » and extinction profiles averaged over South Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same AOD and extinction profiles, the two runs produce significantly different radiative effects over land and oceans. On the regional mean basis, Case I generates 48 % more heating in the atmosphere and 21 % more dimming at the surface than Case II. Case I also produces stronger cooling responses over the land from the longwave radiation adjustment and boundary layer mixing. These rapid adjustments offset the stronger radiative heating in Case I and lead to an overall lower-troposphere cooling up to -0.7 K day−1, which is smaller than that in Case II. Over the ocean, direct radiative effects dominate the heating rate changes in the lower atmosphere lacking such surface and lower atmosphere adjustments due to fixed sea surface temperature, and the strongest atmospheric warming is obtained in Case I. Consequently, atmospheric dynamics (boundary layer heights and meridional circulation) and thermodynamic processes (water vapor and cloudiness) are shown to respond

  9. Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia

    SciTech Connect

    Feng, Y.; Kotamarthi, V. R.; Coulter, R.; Zhao, C.; Cadeddu, M.

    2016-01-01

    Aerosol radiative effects and thermodynamic responses over South Asia are examined with the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of aerosol optical depths (AODs) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in northern India. The WRF-Chem model is found to heavily underestimate the AOD during the simulated pre-monsoon month and about 83 % of the model's low bias is due to aerosol extinctions below ~2 km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AOD and extinction profiles averaged over South Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same AOD and extinction profiles, the two runs produce significantly different radiative effects over land and oceans. On the regional mean basis, Case I generates 48 % more heating in the atmosphere and 21 % more dimming at the surface than Case II. Case I also produces stronger cooling responses over the land from the longwave radiation adjustment and boundary layer mixing. These rapid adjustments offset the stronger radiative heating in Case I and lead to an overall lower-troposphere cooling up to -0.7 K day−1, which is smaller than that in Case II. Over the ocean, direct radiative effects dominate the heating rate changes in the lower atmosphere lacking such surface and lower atmosphere adjustments due to fixed sea surface temperature, and the strongest atmospheric warming is obtained in Case I. Consequently, atmospheric dynamics (boundary layer heights and meridional circulation) and thermodynamic processes (water vapor and cloudiness) are shown to

  10. Lidar Observations of the Vertical Structure of Ozone and Aerosol during Wintertime High-Ozone Episodes Associated with Oil and Gas Exploration in the Uintah Basin

    NASA Astrophysics Data System (ADS)

    Senff, C. J.; Langford, A. O.; Banta, R. M.; Alvarez, R. J.; Weickmann, A.; Sandberg, S.; Marchbanks, R. D.; Brewer, A.; Hardesty, R. M.

    2013-12-01

    The Uintah Basin in northeast Utah has been experiencing extended periods of poor air quality in the winter months including very high levels of surface ozone. To investigate the causes of these wintertime ozone pollution episodes, two comprehensive studies were undertaken in January/February of 2012 and 2013. As part of these Uintah Basin Ozone Studies (UBOS), NOAA deployed its ground-based, scanning Tunable Optical Profiler for Aerosol and oZone (TOPAZ) lidar to document the vertical structure of ozone and aerosol backscatter from near the surface up to about 3 km above ground level (AGL). TOPAZ, along with a comprehensive set of chemistry and meteorological measurements, was situated in both years at the Horse Pool site at the northern edge of a large concentration of gas producing wells in the eastern part of the Uintah Basin. The 2012 study was characterized by unusually warm and snow-free condition and the TOPAZ lidar observed deep boundary layers (BL) and mostly well-mixed vertical ozone profiles at or slightly above tropospheric background levels. During UBOS 2013, winter weather conditions in the Uintah Basin were more typical with snow-covered ground and a persistent, shallow cold-pool layer. The TOPAZ lidar characterized with great temporal and spatial detail the evolution of multiple high-ozone episodes as well as cleanout events caused by the passage of synoptic-scale storm systems. Despite the snow cover, the TOPAZ observations show well-mixed afternoon ozone and aerosol profiles up to about 100 m AGL. After several days of pollutant buildup, BL ozone values reached 120-150 ppbv. Above the mixed layer, ozone values gradually decreased to tropospheric background values of around 50 ppbv throughout the several-hundred-meter-deep cold-pool layer and then stayed constant above that up to about 3 km AGL. During the ozone episodes, the lidar observations show no indication of either vertical or horizontal transport of high ozone levels to the surface, thus

  11. Climatological simulations of ozone and atmospheric aerosols in the Greater Cairo region

    SciTech Connect

    Steiner, A. L.; Tawfik, A. B.; Shalaby, A.; Zakey, A. S.; Abdel Wahab, M. M.; Salah, Z.; Solmon, F.; Sillman, S.; Zaveri, Rahul A.

    2014-04-16

    An integrated chemistry-climate model (RegCM4-CHEM) simulates present-day climate, ozone and tropospheric aerosols over Egypt with a focus on Greater Cairo (GC) region. The densley populated GC region is known for its severe air quality issues driven by high levels of anthropogenic pollution in conjuction with natural sources such as dust and agricultural burning events. We find that current global emission inventories underestimate key pollutants such as nitrogen oxides and anthropogenic aerosol species. In the GC region, average-ground-based NO2 observations of 40-60 ppb are substantially higher than modeled estimates (5-10 ppb), likely due to model grid resolution, improper boundary layer representation, and poor emissions inventories. Observed ozone concentrations range from 35 ppb (winter) to 80 ppb (summer). The model reproduces the seasonal cycle fairly well, but modeled summer ozone is understimated by approximately 15 ppb and exhibits little interannual variability. For aerosols, springtime dust events dominate the seasonal aerosol cycle. The chemistry-climate model captures the springtime peak aerosol optical depth (AOD) of 0.7-1 but is slightly greater than satellite-derived AOD. Observed AOD decreases in the summer and increases again in the fall due to agricultural burning events in the Nile Delta, yet the model underestimates this fall observed AOD peak, as standard emissions inventories underestimate this burning and the resulting aerosol emissions. Our comparison of modeled gas and particulate phase atmospheric chemistry in the GC region indicates that improved emissions inventories of mobile sources and other anthropogenic activities are needed to improve air quality simulations in this region.

  12. Role of Climate Change in Global Predictions of Future Tropospheric Ozone and Aerosols

    NASA Technical Reports Server (NTRS)

    Liao, Hong; Chen, Wei-Ting; Seinfeld, John H.

    2006-01-01

    A unified tropospheric chemistry-aerosol model within the Goddard Institute for Space Studies general circulation model II is applied to simulate an equilibrium CO2-forced climate in the year 2100 to examine the effects of climate change on global distributions of tropospheric ozone and sulfate, nitrate, ammonium, black carbon, primary organic carbon, secondary organic carbon, sea salt, and mineral dust aerosols. The year 2100 CO2 concentration as well as the anthropogenic emissions of ozone precursors and aerosols/aerosol precursors are based on the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (SRES) A2. Year 2100 global O3 and aerosol burdens predicted with changes in both climate and emissions are generally 5-20% lower than those simulated with changes in emissions alone; as exceptions, the nitrate burden is 38% lower, and the secondary organic aerosol burden is 17% higher. Although the CO2-driven climate change alone is predicted to reduce the global O3 concentrations over or near populated and biomass burning areas because of slower transport, enhanced biogenic hydrocarbon emissions, decomposition of peroxyacetyl nitrate at higher temperatures, and the increase of O3 production by increased water vapor at high NOx levels. The warmer climate influences aerosol burdens by increasing aerosol wet deposition, altering climate-sensitive emissions, and shifting aerosol thermodynamic equilibrium. Climate change affects the estimates of the year 2100 direct radiative forcing as a result of the climate-induced changes in burdens and different climatological conditions; with full gas-aerosol coupling and accounting for ozone and direct radiative forcings by the O2, sulfate, nitrate, black carbon, and organic carbon are predicted to be +0.93, -0.72, -1.0, +1.26, and -0.56 W m(exp -2), respectively, using present-day climate and year 2100 emissions, while they are predicted to be +0.76, -0.72, 0.74, +0.97, and -0.58 W m(exp -2

  13. A comparison of acid aerosol and ozone exposure patterns in a summertime study of metropolitan Philadelphia

    SciTech Connect

    Waldman, J.M.; Liang, C.S.K.; Koutrakis, P.; Suh, H.; Allen, G.; Burton, R.; Wilson, W.E.

    1994-12-31

    A study of acid aerosol and ozone exposure patterns was conducted for metropolitan Philadelphia between June and August 1992. Included in the study design were daily monitoring of particulate strong acidity (PSA), sulfate (SO{sub 4}{sup {minus}2}) and hourly ozone data (O{sub 3}) at a citywide network. A continuous sulfate thermal speciation analyzer at one site collected hourly concentration data for SO{sub 4}{sup {minus}2} aerosol. The current paper presents temporal patterns of continuous measurements for O{sub 3} and SO{sub 4}{sup {minus}2} aerosol. Both pollutants had similar daily peak periods in the mid-afternoon, although the range for O{sub 3} was much greater than for SO{sub 4}{sup {minus}2} aerosol. The daily peak values were also correlated for the two species during the study period. It seems that many of the same meteorological factors affect the spatial and temporal patterns for these lung irritants. Hence, the similarity in exposure patterns for O{sub 3} and SO{sub 4}{sup {minus}2} aerosol is reason for concern, regarding possible synergism from coincident doses.

  14. Stratospheric ozone depletion over Antarctica - Role of aerosols based on SAGE II satellite observations

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    The physical characteristics of the Antarctic stratospheric aerosol are investigated via a comprehensive analysis of the SAGE II data during the most severe ozone depletion episode of October 1987. The aerosol size distribution is found to be bimodal in several instances using the randomized minimization search technique, which suggests that the distribution of a single mode may be used to fit the data in the retrieved size range only at the expense of resolution for the larger particles. On average, in the region below 18 km, a wavelike perturbation with the upstream tilting for the parameters of mass loading, total number, and surface area concentration is found to be located just above the region of the most severe ozone depletion.

  15. Markers of heterogeneous reaction products in α-pinene ozone secondary organic aerosol

    NASA Astrophysics Data System (ADS)

    Czoschke, Nadine M.; Jang, Myoseon

    A gas chromatograph iontrap mass spectrometer (GC-ITMS) was used to analyze the gas-and particle-phase products of α-pinene ozone oxidation in the presence of three different inorganic seed aerosols: sodium chloride, ammonium sulfate only, and ammonium sulfate with sulfuric acid. Products of α-pinene ozone oxidation common to the literature showed little difference in gas or particle-phase concentrations between seed types within the precision of the measurements even though significantly different aerosol yields were found between seed types. Small amounts of ring-opening products of four-membered cyclic oxygenates and markers of aldol condensation products were tentatively identified in the particle-phase for all seed types. These tentatively identified products are thought to be the result of acid-catalyzed heterogeneous reactions in the particle-phase or during sampling processes or analysis. The mechanisms for their formation are also proposed in this study.

  16. Quantification of model uncertainty in aerosol optical thickness retrieval from Ozone Monitoring Instrument (OMI) measurements

    NASA Astrophysics Data System (ADS)

    Määttä, A.; Laine, M.; Tamminen, J.; Veefkind, J. P.

    2013-09-01

    We study uncertainty quantification in remote sensing of aerosols in the atmosphere with top of the atmosphere reflectance measurements from the nadir-viewing Ozone Monitoring Instrument (OMI). Focus is on the uncertainty in aerosol model selection of pre-calculated aerosol models and on the statistical modelling of the model inadequacies. The aim is to apply statistical methodologies that improve the uncertainty estimates of the aerosol optical thickness (AOT) retrieval by propagating model selection and model error related uncertainties more realistically. We utilise Bayesian model selection and model averaging methods for the model selection problem and use Gaussian processes to model the smooth systematic discrepancies from the modelled to observed reflectance. The systematic model error is learned from an ensemble of operational retrievals. The operational OMI multi-wavelength aerosol retrieval algorithm OMAERO is used for cloud free, over land pixels of the OMI instrument with the additional Bayesian model selection and model discrepancy techniques. The method is demonstrated with four examples with different aerosol properties: weakly absorbing aerosols, forest fires over Greece and Russia, and Sahara dessert dust. The presented statistical methodology is general; it is not restricted to this particular satellite retrieval application.

  17. Uncertainty quantification in aerosol optical thickness retrieval from Ozone Monitoring Instrument (OMI) measurements

    NASA Astrophysics Data System (ADS)

    Määttä, A.; Laine, M.; Tamminen, J.; Veefkind, J. P.

    2013-10-01

    The space borne measurements provide global view of atmospheric aerosol distribution. The Ozone Monitoring Instrument (OMI) on board NASAs Earth Observing System (EOS) Aura satellite is a Dutch-Finnish nadir-viewing solar backscatter spectrometer measuring in the ultraviolet and visible wavelengths. OMI measures several trace gases and aerosols that are important in many air quality and climate studies. The OMI aerosol measurements are used, for example, for detecting volcanic ash plumes, wild fires and transportation of desert dust. We present a methodology for improving the uncertainty quantification in the aerosols retrieval algorithm. We have used the OMI measurements in this feasibility study. Our focus is on the uncertainties originating from the pre-calculated aerosol models. These models are never complete descriptions of the reality. This aerosol model uncertainty is estimated using Gaussian processes with computational tools from spatial statistics. Our approach is based on smooth systematic differences between the observed and modelled reflectances. When acknowledging this model inadequacy in the estimation of aerosol optical thickness (AOT), the uncertainty estimates are more realistic. We present here a real world example of applying the methodology.

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

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Butler, Carolyn F.; Kooi, Susan A.

    1991-01-01

    Ozone (O3) and aerosol distributions were measured from an aircraft using a differential absorption lidar (DIAL) system as part of the 1988 NASA Global Tropospheric Experiment - Arctic Boundary Layer Experiment (ABLE-3A) to study the sources and sinks of gases and aerosols over the tundra regions of Alaska during the summer. The tropospheric O3 budget over the Arctic was found to be strongly influenced by stratospheric intrusions. Regions of low aerosol scattering and enhanced O3 mixing ratios were usually correlated with descending air from the upper troposphere or lower stratosphere. Several cases of continental polar air masses were examined during the experiment. The aerosol scattering associated with these air masses was very low, and the atmospheric distribution of aerosols was quite homogeneous for those air masses that had been transported over the ice for greater than or = 3 days. The transition in O3 and aerosol distributions from tundra to marine conditions was examined several times. The aerosol data clearly show an abrupt change in aerosol scattering properties within the mixed layer from lower values over the tundra to generally higher values over the water. The distinct differences in the heights of the mixed layers in the two regions was also readily apparent. Several cases of enhanced O3 were observed during ABLE-3 in conjunction with enhanced aerosol scattering in layers in the free atmosphere. Examples are presented of the large scale variations of O3 and aerosols observed with the airborne lidar system from near the surface to above the tropopause over the Arctic during ABLE-3.

  19. Tropical intercontinental optical measurement network of aerosol, precipitable water and total column ozone

    NASA Technical Reports Server (NTRS)

    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.

  20. Reactive nitrogen, ozone, and nitrate aerosols observed in the Arctic stratosphere in January 1990

    SciTech Connect

    Kondo, Y.; Koike, M.; Iwasaka, Y.; Hayashi, M.; Aimedieu, P.; Newman, P.A.; Matthews, W.A.; Sheldon, W.R.

    1992-08-20

    This paper reports balloon borne measurements on two days in January 1990, from Sweden, of stratospheric densities of reactive nitrogen, nitrate aerosols, and ozone. On one days the measurements were inside the polar vortex, and on the second outside. Reactive nitrogen levels were depressed inside the vortex, which is interpreted in terms of the cold temperatures during December and early January which other measurements support. Denitrification is observed inside the vortex, relative to typical number densities observed when outside the vortex.

  1. A study on the aerosol extinction-to-backscatter ratio with combination of micro-pulse LIDAR and MODIS over Hong Kong

    NASA Astrophysics Data System (ADS)

    He, Q. S.; Li, C. C.; Mao, J. T.; Lau, A. K. H.; Li, P. R.

    2006-08-01

    The aerosol extinction-to-backscatter ratio is an important parameter for inverting LIDAR signals in the LIDAR equation. It is a complicated function of the aerosol microphysical characteristics. In this paper, a method to retrieve the column-averaged aerosol extinction-to-backscatter ratio by constraining the aerosol optical depths (AOD) from a Micro-pulse LIDAR (MPL) by the AOD measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) is presented. Both measurements were taken on cloud free days between 1 May 2003 and 30 June 2004 over Hong Kong, a coastal city in south China. Simultaneous measurements of aerosol scattering coefficients with a forward scattering visibility sensor are compared with the LIDAR retrieval of aerosol extinction coefficients. The data are then analyzed to determine seasonal trends of the aetrosol extinction-to-backscatter ratio. In addition, the relationships between the extinction-to-backscatter ratio and wind conditions as well as other aerosol microphysical parameters are presented. The mean aerosol extinction-to-backscatter ratio for the whole period was found to be 29.1±5.8 sr, with a minimum of 18 sr in July 2003 and a maximum of 44 sr in March 2004. The ratio is lower in summer because of the dominance of oceanic aerosols in association with the prevailing southwesterly monsoon. In contrast, relatively larger ratios are noted in spring and winter because of the increased impact of local and regional industrial pollutants associated with the northerly monsoon. The extended LIDAR measurements over Hong Kong provide not only a more accurate retrieval of aerosol extinction coefficient profiles, but also significant substantial information for air pollution and climate studies in the region.

  2. Effect of ozone exposure on the dispersion of inhaled aerosol boluses in healthy human subjects

    SciTech Connect

    Keefe, M.J.; Bennett, W.D.; Dewitt, P.; Seal, E.; Strong, A.A.

    1990-12-06

    Acute exposure of humans to low levels of ozone are known to cause decreases FVC and increases sRaw. These alterations in lung function do not, however, elucidate the potential for acute small airways responses. In the study the authors employed a test of aerosol dispersion to examine the potential effects of ozone on small airways in humans. Twenty-two healthy non-smoking male volunteers were exposed to 0.4 ppm ozone for one hour while exercising at 20 l/min/m{sup 2} (BSA). Prior to and immediately following exposure, tests of spirometry (FVC, FEV1, and FEF25-75) and plethysmography (Raw and sRaw) were performed. Subjects also performed an aerosol dispersion test before and after exposure. Each test involved a subject inhaling five to seven breaths of a 300 ml bolus of a 0.5 micrometers triphenyl phosphate (TPP) aerosol injected into a 2 liters tidal volume. The bolus was injected into the tidal breath at three different depths: at depth A the bolus was injected after 1.6 liters of clean air was inhaled from FRC; at depth B after 1.2 liters; and at depth C after 1.2 liters but with inhalation beginning from RV. The primary measure of bolus dispersion was the expired half-width (HW).

  3. Secondary organic aerosol formation from ozone-initiated reactions with nicotine and secondhand tobacco smoke

    NASA Astrophysics Data System (ADS)

    Sleiman, Mohamad; Destaillats, Hugo; Smith, Jared D.; Liu, Chen-Lin; Ahmed, Musahid; Wilson, Kevin R.; Gundel, Lara A.

    2010-11-01

    We used controlled laboratory experiments to evaluate the aerosol-forming potential of ozone reactions with nicotine and secondhand smoke. Special attention was devoted to real-time monitoring of the particle size distribution and chemical composition of SOA as they are believed to be key factors determining the toxicity of SOA. The experimental approach was based on using a vacuum ultraviolet photon ionization time-of-flight aerosol mass spectrometer (VUV-AMS), a scanning mobility particle sizer (SMPS) and off-line thermal desorption coupled to mass spectrometry (TD-GC-MS) for gas-phase byproducts analysis. Results showed that exposure of SHS to ozone induced the formation of ultrafine particles (<100 nm) that contained high molecular weight nitrogenated species ( m/ z 400-500), which can be due to accretion/acid-base reactions and formation of oligomers. In addition, nicotine was found to contribute significantly (with yields 4-9%) to the formation of secondary organic aerosol through reaction with ozone. The main constituents of the resulting SOA were tentatively identified and a reaction mechanism was proposed to elucidate their formation. These findings identify a new component of thirdhand smoke that is associated with the formation of ultrafine particles (UFP) through oxidative aging of secondhand smoke. The significance of this chemistry for indoor exposure and health effects is highlighted.

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

    NASA Technical Reports Server (NTRS)

    Pepin, T. J.

    1977-01-01

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

  5. Ozone Observations by the Gas and Aerosol Measurement Sensor during SOLVE II

    NASA Technical Reports Server (NTRS)

    Pitts, M. C.; Thomason, L. W.; Zawodny, J. M.; Wenny, B. N.; Livingston, J. M.; Russell, P. B.; Yee, J.-H.; Swartz, W. H.; Shetter, R. E.

    2006-01-01

    The Gas and Aerosol Measurement Sensor (GAMS) was deployed aboard the NASA DC-8 aircraft during the second SAGE III Ozone Loss and Validation Experiment (SOLVE II). GAMS acquired line-of-sight (LOS) direct solar irradiance spectra during the sunlit portions of ten science flights of the DC-8 between 12 January and 4 February 2003. Differential line-of-sight (DLOS) optical depth spectra are produced from the GAMS raw solar irradiance spectra. Then, DLOS ozone number densities are retrieved from the GAMS spectra using a multiple linear regression spectral fitting technique. Both the DLOS optical depth spectra and retrieved ozone data are compared with coincident measurements from two other solar instruments aboard the DC-8 platform to demonstrate the robustness and stability of the GAMS data. The GAMS ozone measurements are then utilized to evaluate the quality of the Wulf band ozone cross sections, a critical component of the SAGE III aerosol, water vapor, and temperature/pressure retrievals. Results suggest the ozone cross section compilation of Shettle and Anderson currently used operationally in SAGE III data processing may be in error by as much as 10-20% in theWulf bands, and their lack of reported temperature dependence is a significant deficiency. A second, more recent, cross section database compiled for the SCIAMACHY satellite mission appears to be of much better quality in the Wulf bands, but still may have errors as large as 5% near the Wulf band absorption peaks, which is slightly larger than their stated uncertainty. Additional laboratory measurements of the Wulf band cross sections should be pursued to further reduce their uncertainty and better quantify their temperature dependence.

  6. Evaluating Nighttime CALIOP 0.532 micron Aerosol Optical Depth and Extinction Coefficient Retrievals

    NASA Technical Reports Server (NTRS)

    Campbell, J. R.; Tackett, J. L.; Reid, J. S.; Zhang, J.; Curtis, C. A.; Hyer, E. J.; Sessions, W. R.; Westphal, D. L.; Prospero, J. M.; Welton, E. J.; Omar, A. H.; Vaughan, M. A.; Winker, D. M.

    2012-01-01

    NASA Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) Version 3.01 5-km nighttime 0.532 micron aerosol optical depth (AOD) datasets from 2007 are screened, averaged and evaluated at 1 deg X 1 deg resolution versus corresponding/co-incident 0.550 micron AOD derived using the US Navy Aerosol Analysis and Prediction System (NAAPS), featuring two-dimensional variational assimilation of quality-assured NASA Moderate Resolution Imaging Spectroradiometer (MODIS) and Multi-angle Imaging Spectroradiometer (MISR) AOD. In the absence of sunlight, since passive radiometric AOD retrievals rely overwhelmingly on scattered radiances, the model represents one of the few practical global estimates available from which to attempt such a validation. Daytime comparisons, though, provide useful context. Regional-mean CALIOP vertical profiles of night/day 0.532 micron extinction coefficient are compared with 0.523/0.532 micron ground-based lidar measurements to investigate representativeness and diurnal variability. In this analysis, mean nighttime CALIOP AOD are mostly lower than daytime (0.121 vs. 0.126 for all aggregated data points, and 0.099 vs. 0.102 when averaged globally per normalised 1 deg. X 1 deg. bin), though the relationship is reversed over land and coastal regions when the data are averaged per normalised bin (0.134/0.108 vs. 0140/0.112, respectively). Offsets assessed within single bins alone approach +/- 20 %. CALIOP AOD, both day and night, are higher than NAAPS over land (0.137 vs. 0.124) and equal over water (0.082 vs. 0.083) when averaged globally per normalised bin. However, for all data points inclusive, NAAPS exceeds CALIOP over land, coast and ocean, both day and night. Again, differences assessed within single bins approach 50% in extreme cases. Correlation between CALIOP and NAAPS AOD is comparable during both day and night. Higher correlation is found nearest the equator, both as a function of sample size and relative signal magnitudes inherent at

  7. Simulations of aerosols and their effects on photolysis and ozone formation in Mexico City

    NASA Astrophysics Data System (ADS)

    Li, G.; Zavala, M.; Lei, W.; Karydis, V. A.; Tsimpidi, A. P.; Pandis, S.; Molina, L. T.

    2009-04-01

    Atmospheric aerosols, formed from natural and anthropogenic sources, are believed to be associated with adverse human effects at high levels in polluted urban areas. They also play a key role in climate through direct and indirect effects. Therefore, accurate simulations of aerosol composition and distribution in the atmospheric models are important in evaluating their impact on environment and climate. In the present study, a flexible gas phase chemical module with SAPRC mechanism and the CMAQ/models3 aerosol module developed by EPA have been implemented into the WRF-CHEM model. Additionally, to further improve the aerosol, especially the secondary organic aerosol (SOA) simulations, an advanced SOA module [Tsimpidi et al., 2009] has been incorporated into the WRF-CHEM model. The new SOA module is based on the volatility basis-set approach in which both primary and secondary organic components are assumed to be semivolatile and photochemically reactive [Lane et al., 2008]. Gas phase species and aerosol simulation results are compared with the available measurements obtained during the MILAGRO 2006 campaign. When the advanced SOA mechanism is employed, the SOA simulations are significantly improved. Furthermore, the aerosol impacts on the photochemistry in Mexico City have been evaluated using the FTUV [Tie et al., 2005]. Aerosol optical properties are calculated using the Mie theory and compared with available observations in Mexico City [Paredes-Miranda et al., 2008]. Aerosols, principally black carbon, reduce the photolysis frequencies of J[O3(1D)] and J[NO2] in the planetary boundary layer and hence decrease the ground-level ozone concentration. Our study demonstrates that the impact of aerosols on photochemistry is significant in polluted urban atmosphere. References: Lane, T. E., N. M. Donahue, and S. N. Pandis (2008), Simulating secondary organic aerosol formation using the volatility basis-set approach in a chemical transport model, PMCAMx, Atmos. Environ

  8. In situ vertical profiles of aerosol extinction, mass, and composition over the southeast United States during SENEX and SEAC4RS: observations of a modest aerosol enhancement aloft

    NASA Astrophysics Data System (ADS)

    Wagner, N. L.; Brock, C. A.; Angevine, W. M.; Beyersdorf, A.; Campuzano-Jost, P.; Day, D.; de Gouw, J. A.; Diskin, G. S.; Gordon, T. D.; Graus, M. G.; Holloway, J. S.; Huey, G.; Jimenez, J. L.; Lack, D. A.; Liao, J.; Liu, X.; Markovic, M. Z.; Middlebrook, A. M.; Mikoviny, T.; Peischl, J.; Perring, A. E.; Richardson, M. S.; Ryerson, T. B.; Schwarz, J. P.; Warneke, C.; Welti, A.; Wisthaler, A.; Ziemba, L. D.; Murphy, D. M.

    2015-06-01

    Vertical profiles of submicron aerosol from in situ aircraft-based measurements were used to construct aggregate profiles of chemical, microphysical, and optical properties. These vertical profiles were collected over the southeastern United States (SEUS) during the summer of 2013 as part of two separate field studies: the Southeast Nexus (SENEX) study and the Study of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS). Shallow cumulus convection was observed during many profiles. These conditions enhance vertical transport of trace gases and aerosol and create a cloudy transition layer on top of the sub-cloud mixed layer. The trace gas and aerosol concentrations in the transition layer were modeled as a mixture with contributions from the mixed layer below and the free troposphere above. The amount of vertical mixing, or entrainment of air from the free troposphere, was quantified using the observed mixing ratio of carbon monoxide (CO). Although the median aerosol mass, extinction, and volume decreased with altitude in the transition layer, they were ~10 % larger than expected from vertical mixing alone. This enhancement was likely due to secondary aerosol formation in the transition layer. Although the transition layer enhancements of the particulate sulfate and organic aerosol (OA) were both similar in magnitude, only the enhancement of sulfate was statistically significant. The column integrated extinction, or aerosol optical depth (AOD), was calculated for each individual profile, and the transition layer enhancement of extinction typically contributed less than 10 % to the total AOD. Our measurements and analysis were motivated by two recent studies that have hypothesized an enhanced layer of secondary aerosol aloft to explain the summertime enhancement of AOD (2-3 times greater than winter) over the southeastern United States. The first study attributes the layer aloft to secondary organic aerosol (SOA) while

  9. Tropospheric ozone and aerosol long-term trends over the Indo-Gangetic Plain (IGP), India

    NASA Astrophysics Data System (ADS)

    Lal, D. M.; Ghude, Sachin D.; Patil, S. D.; Kulkarni, Santosh H.; Jena, Chinmay; Tiwari, S.; Srivastava, Manoj K.

    2012-10-01

    We investigate, for the first time, long-term trends in tropospheric ozone and its association with the industrial growth in large part of India. A multifunction regression model has been used to estimate the trends in tropospheric ozone between 1979 and 1992 over the Indian region. Increasing trends in tropospheric ozone are observed over most of the regions of India. Recent year's (2005-2010) data also shows the similar features. It is quite consistent with the observed trends in coal (9.2%/year) and petroleum (8.3%/year) consumption, and NOx and CO emissions in India during the study period. The regressed Tropospheric Ozone Residual (TOR) pattern during monsoon season shows large trend over the entire Indo-Gangetic region and is largest, 6-7.2% per decade, over the northeastern Gangetic plain of India. Annually, trend of about 0.4 ± 0.25 (1σ) % per year has been seen over the northeastern Gangetic region. Similar positive trend in aerosol index (AI) (1.7 ± 1.2 (1σ) % per year) is also detected over this region. The quality of correlation between TOR and AI suggested that tropospheric ozone appeared to be influenced by the increased anthropogenic activities in this region.

  10. An Aerosol Extinction-to-Backscatter Ratio Database Derived from the NASA Micro-Pulse Lidar Network: Applications for Space-based Lidar Observations

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; Campbell, James R.; Spinhime, James D.; Berkoff, Timothy A.; Holben, Brent; Tsay, Si-Chee; Bucholtz, Anthony

    2004-01-01

    Backscatter lidar signals are a function of both backscatter and extinction. Hence, these lidar observations alone cannot separate the two quantities. The aerosol extinction-to-backscatter ratio, S, is the key parameter required to accurately retrieve extinction and optical depth from backscatter lidar observations of aerosol layers. S is commonly defined as 4*pi divided by the product of the single scatter albedo and the phase function at 180-degree scattering angle. Values of S for different aerosol types are not well known, and are even more difficult to determine when aerosols become mixed. Here we present a new lidar-sunphotometer S database derived from Observations of the NASA Micro-Pulse Lidar Network (MPLNET). MPLNET is a growing worldwide network of eye-safe backscatter lidars co-located with sunphotometers in the NASA Aerosol Robotic Network (AERONET). Values of S for different aerosol species and geographic regions will be presented. A framework for constructing an S look-up table will be shown. Look-up tables of S are needed to calculate aerosol extinction and optical depth from space-based lidar observations in the absence of co-located AOD data. Applications for using the new S look-up table to reprocess aerosol products from NASA's Geoscience Laser Altimeter System (GLAS) will be discussed.

  11. Future Climate Impacts of Direct Radiative Forcing Anthropogenic Aerosols, Tropospheric Ozone, and Long-lived Greenhouse Gases

    NASA Technical Reports Server (NTRS)

    Chen, Wei-Ting; Liao, Hong; Seinfeld, John H.

    2007-01-01

    Long-lived greenhouse gases (GHGs) are the most important driver of climate change over the next century. Aerosols and tropospheric ozone (O3) are expected to induce significant perturbations to the GHG-forced climate. To distinguish the equilibrium climate responses to changes in direct radiative forcing of anthropogenic aerosols, tropospheric ozone, and GHG between present day and year 2100, four 80-year equilibrium climates are simulated using a unified tropospheric chemistry-aerosol model within the Goddard Institute for Space Studies (GISS) general circulation model (GCM) 110. Concentrations of sulfate, nitrate, primary organic (POA) carbon, secondary organic (SOA) carbon, black carbon (BC) aerosols, and tropospheric ozone for present day and year 2100 are obtained a priori by coupled chemistry-aerosol GCM simulations, with emissions of aerosols, ozone, and precursors based on the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenario (SRES) A2. Changing anthropogenic aerosols, tropospheric ozone, and GHG from present day to year 2100 is predicted to perturb the global annual mean radiative forcing by +0.18 (considering aerosol direct effects only), +0.65, and +6.54 W m(sup -2) at the tropopause, and to induce an equilibrium global annual mean surface temperature change of +0.14, +0.32, and +5.31 K, respectively, with the largest temperature response occurring at northern high latitudes. Anthropogenic aerosols, through their direct effect, are predicted to alter the Hadley circulation owing to an increasing interhemispheric temperature gradient, leading to changes in tropical precipitation. When changes in both aerosols and tropospheric ozone are considered, the predicted patterns of change in global circulation and the hydrological cycle are similar to those induced by aerosols alone. GHG-induced climate changes, such as amplified warming over high latitudes, weakened Hadley circulation, and increasing precipitation over the

  12. Lower tropospheric ozone and aerosol measurements at a coastal mountain site in Northern California

    NASA Astrophysics Data System (ADS)

    Post, A.; Conley, S. A.; Zhao, Y.; Cliff, S. S.; Faloona, I. C.; Wexler, A. S.; Lighthall, D.

    2012-12-01

    Increasing concern over the impacts of exogenous air pollution in California's Central Valley have prompted the establishment of a coastal, high altitude monitoring site at the Chews Ridge Observatory (1550 m) approximately 30 km east of Point Sur in Monterey County. Six months of ozone and aerosol measurements are presented in the context of long-range transport and its potential impact on surface air quality in the southern San Joaquin Valley. Moreover, approximately monthly ozone surveys are conducted by aircraft upwind, over the Pacific Ocean, and downwind, over the Central Valley, to characterize horizontal and vertical transport across the coastal mountains. The measurements exhibit no systematic diurnal variations of ozone or water vapor, an indication that the site primarily samples lower free tropospheric air which has not been significantly influenced by either local emissions or convective coupling to the surface. Aerosol size is measured with a scanning mobility particle sizer and composition is analyzed with an 8-stage rotating drum impactor whose substrates are characterized by X-ray fluorescence. Various elemental ratios and back trajectory calculations are used to infer the temporal patterns of influence that long range transport has on California air quality.

  13. Validation of Temperature Measurements from the Airborne Raman Ozone Temperature and Aerosol Lidar During SOLVE

    NASA Technical Reports Server (NTRS)

    Burris, John; McGee, Thomas; Hoegy, Walter; Lait, Leslie; Twigg, Laurence; Sumnicht, Grant; Heaps, William; Hostetler, Chris; Bui, T. Paul; Neuber, Roland; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    The Airborne Raman Ozone, Temperature and Aerosol Lidar (AROTEL) participated in the recent Sage III Ozone Loss and Validation Experiment (SOLVE) by providing profiles of aerosols, polar stratospheric clouds (PSCs), ozone and temperature with high vertical and horizontal resolution. Temperatures were derived from just above the aircraft to approximately 60 kilometers geometric altitude with a reported vertical resolution of between 0.5 and 1.5 km. The horizontal footprint varied from 4 to 70 km. This paper explores the measurement uncertainties associated with the temperature retrievals and makes comparisons with independent, coincident, measurements of temperature. Measurement uncertainties range from 0.1 K to approximately 4 K depending on altitude and integration time. Comparisons between AROTEL and balloon sonde temperatures retrieved under clear sky conditions using both Rayleigh and Raman scattered data showed AROTEL approximately 1 K colder than sonde values. Comparisons between AROTEL and the Meteorological Measurement System (MMS) on NASA's ER-2 show AROTEL being from 2-3 K colder for altitudes ranging from 14 to 18 km. Temperature comparisons between AROTEL and the United Kingdom Meteorological Office's model showed differences of approximately 1 K below approximately 25 km and a very strong cold bias of approximately 12 K at altitudes between 30 and 35 km.

  14. Global Impacts of Gas-Phase Chemistry-Aerosol Interactions on Direct Radiative Forcing by Anthropogenic Aerosols and Ozone

    NASA Technical Reports Server (NTRS)

    Liao, Hong; Seinfeld, John H.

    2005-01-01

    We present here a first global modeling study on the influence of gas-phase chemistry/aerosol interactions on estimates of anthropogenic forcing by tropospheric O3 and aerosols. Concentrations of gas-phase species and sulfate, nitrate, ammonium, black carbon, primary organic carbon, secondary organic carbon, sea salt, and mineral dust aerosols in the preindustrial, present-day, and year 2100 (IPCC SRES A2) atmospheres are simulated online in the Goddard Institute for Space Studies general circulation model II' (GISS GCM II'). With fully coupled chemistry and aerosols, the preindustrial, presentday, and year 2100 global burdens of tropospheric ozone are predicted to be 190, 319, and 519 Tg, respectively. The burdens of sulfate, nitrate, black carbon, and organic carbon are predicted respectively to be 0.32. 0.18, 0.01, 0.33 Tg in preindustrial time, 1.40, 0.48, 0.23, 1.60 Tg in presentday, and 1.37, 1.97, 0.54, 3.31 Tg in year 2100. Anthropogenic O3 is predicted to have a globally and annually averaged present-day forcing of +0.22 W m(sup -2) and year 2100 forcing of +0.57 W m(sup -2) at the top of the atmosphere (TOA). Net anthropogenic TOA forcing by internally mixed sulfate, nitrate, organic carbon, and black carbon aerosols is estimated to be virtually zero in the present-day and +0.34 W m(sup -2) in year 2100, whereas it is predicted to be -0.39 W m(sup -2) in present-day and -0.61 W m(sup -2) in year 2100 if the aerosols are externally mixed. Heterogeneous reactions are shown to be important in affecting anthropogenic forcing. When reactions of N2O5, NO3, NO2, and HO2 on aerosols are accounted for, TOA anthropogenic O3 forcing is less by 20-45% in present-day and by 20-32% in year 2100 at mid to high latitudes in the Northern Hemisphere, as compared with values predicted in the absence of heterogeneous gas aerosol reactions. Mineral dust uptake of HNO3 and O3 is shown to have practically no influence on anthropogenic O3 forcing. Heterogeneous reactions of N2Os

  15. Heterogeneous processing of bromine compounds by atmospheric aerosols: Relation to the ozone budget

    SciTech Connect

    Robinson, J.M.; Henson, B.F.; Dubey, M.K.; Casson, J.L.; Johal, M.S.; Wilson, K.R.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The depletion of ozone, particularly above Antarctica, has been investigated extensively to formulate public policy on the use of halocarbons. While it has been shown that heterogeneous reactions of chlorine compounds on stratospheric particulates cause the ozone hole, little is known of the analogous bromine mechanisms, even though it has been recognized for two decades that catalytic destruction of ozone by bromine could be more efficient than chlorine. Furthermore, field measurements and modeling calculations suggest that these heterogeneous (gas/surface) reactions are not restricted to the Antarctic regions but occur globally. The authors have performed laboratory measurements of the uptake of bromine compounds and other halogens on simulated stratospheric aerosols to help elucidate their role in catalytic ozone destruction cycles. Their studies contribute to the data base required to make assessments of the effects of human activities on global change, including the Montreal Protocol.

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

    SciTech Connect

    Newchurch, M.J.

    1986-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

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

  18. Four-year long-path monitoring of ambient aerosol extinction at a central European urban site: dependence on relative humidity

    NASA Astrophysics Data System (ADS)

    Skupin, A.; Ansmann, A.; Engelmann, R.; Seifert, P.; Müller, T.

    2016-02-01

    The ambient aerosol particle extinction coefficient is measured with the Spectral Aerosol Extinction Monitoring System (SÆMS) along a 2.84 km horizontal path at 30-50 m height above ground in the urban environment of Leipzig (51.3° N, 12.4° E), Germany, since 2009. The dependence of the particle extinction coefficient (wavelength range from 300 to 1000 nm) on relative humidity up to almost 100 % was investigated. The main results are presented. For the wavelength of 550 nm, the mean extinction enhancement factor was found to be 1.75 ± 0.4 for an increase of relative humidity from 40 to 80 %. The respective 4-year mean extinction enhancement factor is 2.8 ± 0.6 for a relative-humidity increase from 40 to 95 %. A parameterization of the dependency of the urban particle extinction coefficient on relative humidity is presented. A mean hygroscopic exponent of 0.46 for the 2009-2012 period was determined. Based on a backward trajectory cluster analysis, the dependence of several aerosol optical properties for eight air flow regimes was investigated. Large differences were not found, indicating that local pollution sources widely control the aerosol conditions over the urban site. The comparison of the SÆMS extinction coefficient statistics with respective statistics from ambient AERONET sun photometer observations yields good agreement. Also, time series of the particle extinction coefficient computed from in situ-measured dry particle size distributions and humidity-corrected SÆMS extinction values (for 40 % relative humidity) were found in good overall consistency, which verifies the applicability of the developed humidity parameterization scheme. The analysis of the spectral dependence of particle extinction (Ångström exponent) revealed an increase of the 390-881 nm Ångström exponent from, on average, 0.3 (at 30 % relative humidity) to 1.3 (at 95 % relative humidity) for the 4-year period.

  19. Removal of sulphur from the marine boundary layer by ozone oxidation in sea-salt aerosols

    NASA Astrophysics Data System (ADS)

    Sievering, H.; Boatman, J.; Gorman, E.; Kim, Y.; Anderson, L.; Ennis, G.; Luria, M.; Pandis, S.

    1992-12-01

    The contribution of ozone oxidation in sea-salt aerosols to the cycling of sulfur in the marine boundary layer (MBL) is assessed. It is shown that, due to the effects of mass transfer, the non-sea-salt SO4(2-) so generated will be predominantly associated with particles 2-9 microns in diameter and will accordingly dry-deposit at a rapid rate. Because part of the dimethyl sulfide emitted by marine organisms is converted to SO2 in the MBL, this additional removal pathway for sulfur may markedly reduce the proposed feedback between greenhouse warming, oceanic DMS emissions, and sulfate haze albedos.

  20. In situ measurement of the infrared absorption and extinction of chemical and biologically derived aerosols using flow-through photoacoustics.

    PubMed

    Gurton, Kristan P; Dahmani, Rachid; Ligon, David; Bronk, Burt V

    2005-07-01

    In an effort to establish a more reliable set of optical cross sections for a variety of chemical and biological aerosol simulants, we have developed a flow-through photoacoustic system that is capable of measuring absolute, mass-normalized extinction and absorption cross sections. By employing a flow-through design we avoid issues associated with closed aerosol photoacoustic systems and improve sensitivity. Although the results shown here were obtained for the tunable CO2 laser waveband region, i.e., 9.20-10.80 microm, application to other wavelengths is easily achievable. The aerosols considered are categorized as biological, chemical, and inorganic in origin, i.e., Bacillus atrophaeus endospores, dimethicone silicone oil (SF-96 grade 50), and kaolin clay powder (alumina and silicate), respectively. Results compare well with spectral extinction measured previously by Fourier-transform infrared spectroscopy. Comparisons with Mie theory calculations based on previously published complex indices of refraction and measured size distributions are also presented. PMID:16004057

  1. Total ozone column, aerosol optical depth and precipitable water effects on solar erythemal ultraviolet radiation recorded in Malta.

    NASA Astrophysics Data System (ADS)

    Bilbao, Julia; Román, Roberto; Yousif, Charles; Mateos, David; Miguel, Argimiro

    2013-04-01

    The Universities of Malta and Valladolid (Spain) developed a measurement campaign, which took place in the Institute for Energy Technology in Marsaxlokk (Southern Malta) between May and October 2012, and it was supported by the Spanish government through the Project titled "Measurement campaign about Solar Radiation, Ozone, and Aerosol in the Mediterranean area" (with reference CGL2010-12140-E). This campaign provided the first ground-based measurements in Malta of erythemal radiation and UV index, which indicate the effectiveness of the sun exposure to produce sunburn on human skin. A wide variety of instruments was involved in the campaign, providing a complete atmospheric characterization. Data of erythemal radiation and UV index (from UVB-1 pyranometer), total shortwave radiaton (global and diffuse components from CM-6B pyranometers), and total ozone column, aerosol optical thickness, and precitable water column (from a Microtops-II sunphotometer) were available in the campaign. Ground-based and satellite instruments were used in the analysis, and several intercomparisons were carried out to validate remote sensing data. OMI, GOME, GOME-2, and MODIS instruments, which provide data of ozone, aerosol load and optical properties, were used to this end. The effects on solar radiation, ultraviolet and total shortwave ranges, of total ozone column, aerosol optical thickness and precipitable water column were obtained using radiation measurements at different fixed solar zenith angles. The empirical results shown a determinant role of the solar position, a negligible effect of ozone on total shortwave radiation, and a stronger attenuation provided by aerosol particles in the erythemal radiation. A variety of aerosol types from different sources (desert dust, biomass burning, continental, and maritime) reach Malta, in this campaign several dust events from the Sahara desert occurred and were analyzed establishing the air mass back-trajectories ending at Malta at

  2. Lower tropospheric ozone and aerosol measurements at a coastal mountain site in Central California

    NASA Astrophysics Data System (ADS)

    Post, A.; Faloona, I. C.; Lighthall, D.; Wexler, A. S.; Cliff, S. S.; Conley, S. A.; Zhao, Y.

    2013-12-01

    Increasing concern over the impacts of exogenous air pollution in California's Central Valley has prompted the establishment of a coastal, high altitude monitoring site at the Chews Ridge Observatory (1550 m) approximately 30 km east of Point Sur in Monterey County, operated by the Monterey Institute for Research in Astronomy. Eighteen months of ozone and aerosol measurements are presented in the context of long-range transport and its potential impact on surface air quality in the southern San Joaquin Valley. Moreover, several ozone surveys have been conducted by aircraft upwind, over the Pacific Ocean, and downwind, over the Central Valley, to characterize horizontal and vertical transport across the coastal mountains. Diurnal variations present at Chews Ridge indicate the formation of a convective boundary layer on the ridge during the daytime leading to a 6-8 ppb decrease in ozone accompanied by a rise in specific humidity of 2-3 g/kg due to coupling with the forest. During the nighttime, the sampled air masses are representative of free tropospheric conditions which have not been significantly influenced by either local emissions nor convective coupling to the surface. The maximum daily 8-hour average ozone concentration at Chews Ridge is used in lagged correlation analysis with two sites in the San Joaquin Valley, Fresno and Arvin, to de-emphasize the influence of locally produced, diurnally cycled ozone. The correlation coefficients (~0.60) peak between 9-21 hour lag and tend to decorrelate completely within 4-5 days. These and other analyses along with data provided by the aircraft sampling are used to provide a deeper understanding of ozone transport into the San Joaquin Valley. Aerosol size is measured with a scanning mobility particle sizer and composition is analyzed with an 8-stage rotating drum impactor whose substrates are characterized by X-ray fluorescence. Various elemental ratios and back trajectory calculations are used to infer the temporal

  3. Study of MPLNET-Derived Aerosol Climatology over Kanpur, India, and Validation of CALIPSO Level 2 Version 3 Backscatter and Extinction Products

    NASA Technical Reports Server (NTRS)

    Misra, Amit; Tripathi, S. N.; Kaul, D. S.; Welton, Ellsworth J.

    2012-01-01

    The level 2 aerosol backscatter and extinction profiles from the NASA Micropulse Lidar Network (MPLNET) at Kanpur, India, have been studied from May 2009 to September 2010. Monthly averaged extinction profiles from MPLNET shows high extinction values near the surface during October March. Higher extinction values at altitudes of 24 km are observed from April to June, a period marked by frequent dust episodes. Version 3 level 2 Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) aerosol profile products have been compared with corresponding data from MPLNET over Kanpur for the above-mentioned period. Out of the available backscatter profiles, the16 profiles used in this study have time differences less than 3 h and distances less than 130 km. Among these profiles, four cases show good comparison above 400 m with R2 greater than 0.7. Comparison with AERONET data shows that the aerosol type is properly identified by the CALIOP algorithm. Cloud contamination is a possible source of error in the remaining cases of poor comparison. Another source of error is the improper backscatter-to-extinction ratio, which further affects the accuracy of extinction coefficient retrieval.

  4. Verification and application of the extended spectral deconvolution algorithm (SDA+) methodology to estimate aerosol fine and coarse mode extinction coefficients in the marine boundary layer

    NASA Astrophysics Data System (ADS)

    Kaku, K. C.; Reid, J. S.; O'Neill, N. T.; Quinn, P. K.; Coffman, D. J.; Eck, T. F.

    2014-10-01

    The spectral deconvolution algorithm (SDA) and SDA+ (extended SDA) methodologies can be employed to separate the fine and coarse mode extinction coefficients from measured total aerosol extinction coefficients, but their common use is currently limited to AERONET (AErosol RObotic NETwork) aerosol optical depth (AOD). Here we provide the verification of the SDA+ methodology on a non-AERONET aerosol product, by applying it to fine and coarse mode nephelometer and particle soot absorption photometer (PSAP) data sets collected in the marine boundary layer. Using data sets collected on research vessels by NOAA-PMEL(National Oceanic and Atmospheric Administration - Pacific Marine Environmental Laboratory), we demonstrate that with accurate input, SDA+ is able to predict the fine and coarse mode scattering and extinction coefficient partition in global data sets representing a range of aerosol regimes. However, in low-extinction regimes commonly found in the clean marine boundary layer, SDA+ output accuracy is sensitive to instrumental calibration errors. This work was extended to the calculation of coarse and fine mode scattering coefficients with similar success. This effort not only verifies the application of the SDA+ method to in situ data, but by inference verifies the method as a whole for a host of applications, including AERONET. Study results open the door to much more extensive use of nephelometers and PSAPs, with the ability to calculate fine and coarse mode scattering and extinction coefficients in field campaigns that do not have the resources to explicitly measure these values.

  5. The impacts of volcanic aerosol on stratospheric ozone and the Northern Hemisphere polar vortex: separating radiative-dynamical changes from direct effects due to enhanced aerosol heterogeneous chemistry

    NASA Astrophysics Data System (ADS)

    Muthers, S.; Arfeuille, F.; Raible, C. C.; Rozanov, E.

    2015-10-01

    After major volcanic eruptions the enhanced aerosol causes ozone changes due to greater heterogeneous chemistry on the particle surfaces (HET-AER) and from dynamical effects related to the radiative heating of the lower stratosphere (RAD-DYN). We carry out a series of experiments with an atmosphere-ocean-chemistry-climate model to assess how these two processes change stratospheric ozone and Northern Hemispheric (NH) polar vortex dynamics. Ensemble simulations are performed under present day and preindustrial conditions, and with aerosol forcings representative of different eruption strength, to investigate changes in the response behaviour. We show that the halogen component of the HET-AER effect dominates under present-day conditions with a global reduction of ozone (-21 DU for the strongest eruption) particularly at high latitudes, whereas the HET-AER effect increases stratospheric ozone due to N2O5 hydrolysis in a preindustrial atmosphere (maximum anomalies +4 DU). The halogen-induced ozone changes in the present-day atmosphere offset part of the strengthening of the NH polar vortex during mid-winter (reduction of up to -16 m s-1 in January) and slightly amplify the dynamical changes in the polar stratosphere in late winter (+11 m s-1 in March). The RAD-DYN mechanism leads to positive column ozone anomalies which are reduced in a present-day atmosphere by amplified polar ozone depletion (maximum anomalies +12 and +18 DU for present day and preindustrial, respectively). For preindustrial conditions, the ozone response is consequently dominated by RAD-DYN processes, while under present-day conditions, HET-AER effects dominate. The dynamical response of the stratosphere is dominated by the RAD-DYN mechanism showing an intensification of the NH polar vortex in winter (up to +10 m s-1 in January). Ozone changes due to the RAD-DYN mechanism slightly reduce the response of the polar vortex after the eruption under present-day conditions.

  6. Wavelength-resolved optical extinction measurements of aerosols using broad-band cavity-enhanced absorption spectroscopy over the spectral range of 445-480 nm.

    PubMed

    Zhao, Weixiong; Dong, Meili; Chen, Weidong; Gu, Xuejun; Hu, Changjin; Gao, Xiaoming; Huang, Wei; Zhang, Weijun

    2013-02-19

    Despite the significant progress in the measurements of aerosol extinction and absorption using spectroscopy approaches such as cavity ring-down spectroscopy (CRDS) and photoacoustic spectroscopy (PAS), the widely used single-wavelength instruments may suffer from the interferences of gases absorption present in the real environment. A second instrument for simultaneous measurement of absorbing gases is required to characterize the effect of light extinction resulted from gases absorption. We present in this paper the development of a blue light-emitting diode (LED)-based incoherent broad-band cavity-enhanced spectroscopy (IBBCEAS) approach for broad-band measurements of wavelength-resolved aerosol extinction over the spectral range of 445-480 nm. This method also allows for simultaneous measurement of trace gases absorption present in the air sample using the same instrument. On the basis of the measured wavelength-dependent aerosol extinction cross section, the real part of the refractive index (RI) can be directly retrieved in a case where the RI does not vary strongly with the wavelength over the relevant spectral region. Laboratory-generated monodispersed aerosols, polystyrene latex spheres (PSL) and ammonium sulfate (AS), were employed for validation of the RI determination by IBBCEAS measurements. On the basis of a Mie scattering model, the real parts of the aerosol RI were retrieved from the measured wavelength-resolved extinction cross sections for both aerosol samples, which are in good agreement with the reported values. The developed IBBCEAS instrument was deployed for simultaneous measurements of aerosol extinction coefficient and NO(2) concentration in ambient air in a suburban site during two representative days. PMID:23320530

  7. A broadband cavity-enhanced spectrometer for measuring the extinction of aerosols at blue and near-UV wavelengths

    NASA Astrophysics Data System (ADS)

    Venables, Dean; Fullam, Donovan; Hoa Le, Phuoc; Chen, Jun; Böge, Olaf; Herrmann, Hartmut

    2016-04-01

    We describe a new broadband cavity-enhanced absorption spectrometer for sensitive extinction measurements of aerosols. The instrument is distinguished by its broad and continuous spectral coverage from the near-UV to blue wavelengths (ca. 320 to 450 nm). The short wavelength region has been little explored compared to visible wavelengths, but is important because (1) brown carbon (BrC) absorbs strongly in this wavelength region, and (2) absorption of near-UV radiation in the atmosphere alters the photolysis rate of the key atmospheric species O3, NO2, and HONO, with implications for air quality and atmospheric oxidation capacity. The instrument performance and the effect of a switchable in-line filter are characterised. Early results using the instrument in the TROPOS atmospheric simulation chamber are presented. These experiments include studies of secondary organic aerosol formation (SOA), and biomass burning experiments of rice and wheat straw, followed by experiments simulating particle aging under daytime and nighttime conditions.

  8. A comparison of SAGE 1, SBUV, and Umkehr ozone profiles including a search for Umkehr aerosol effects

    NASA Technical Reports Server (NTRS)

    Newchurch, M. J.; Grams, G. W.; Cunnold, D. M.; Deluisi, J. J.

    1987-01-01

    Using a spatially weighted average for the stratospheric aerosol and gas experiment 1 (SAGE 1) events derived from an autocorrelation analysis, 337 colocated SAGE 1 and Umkehr ozone profiles are found. The total column ozone in layers two through nine measured by SAGE 1 is found to be 4.6 + or - 1.3 percent higher at the 95 percent confidence level than the approximate total column ozone measured by Umkehr. Average layer ozone differences indicate that most of this discrepancy resides in the lower layers. Intercomparison of SAGE 1, Nimbus 7 solar backscattered ultraviolet (SBUV), and Umkehr ozone at stations north of 30 deg indicates that, in layer six, Umkehr values are consistently higher than both SAGE 1 and SBUV by about 10 percent. In layer eight, SBUV ozone is higher than both SAGE 1 and SBUV by about 10 percent. In the upper stratosphere, the SAGE 1-Umkehr ozone differences are small for low stratospheric aerosol optical depth cases, but vary from -3 percent in layer six to -8 percent in layer nine for high optical depth cases.

  9. How Well do State-of-the-Art Techniques Measuring the Vertical Profile of Tropospheric Aerosol Extinction Compare?

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Ferrare, R.; Flynn, C.; Elleman, R.; Covert, D.; Strawa, A.; Welton, E.; Turner, D.; Jonsson, H.; Redemann, J.; Eilers, J.; Ricci, K.; Hallar, A. G.; Clayton, M.; Michalsky, J.; Smirnov, A.; Holben, B.; Barnard, J.

    2006-01-01

    The recent Department of Energy Atmospheric Radiation Measurement (ARM) Aerosol Intensive Operations Period (AIOP, May 2003) yielded one of the best measurement sets obtained to date to assess our ability to measure the vertical profile of ambient aerosol extinction sigma(ep)(lambda) in the lower troposphere. During one month, a heavily instrumented aircraft with well-characterized aerosol sampling ability carrying well-proven and new aerosol instrumentation devoted most of the 60 available flight hours to flying vertical profiles over the heavily instrumented ARM Southern Great Plains (SGP) Climate Research Facility (CRF). This allowed us to compare vertical extinction profiles obtained from six different instruments: airborne Sun photometer (AATS-14), airborne nephelometer/absorption photometer, airborne cavity ring-down system, groundbased Raman lidar, and two ground-based elastic backscatter lidars. We find the in situ measured sigma(ep)(lambda) to be lower than the AATS-14 derived values. Bias differences are 0.002-0.004 Km!1 equivalent to 13-17% in the visible, or 45% in the near-infrared. On the other hand, we find that with respect to AATS-14, the lidar sigma(ep)(lambda) are higher: Bias differences are 0.004 Km(-1) (13%) and 0.007 Km(-1) (24%) for the two elastic backscatter lidars (MPLNET and MPLARM, lambda = 523 nm) and 0.029 Km(-1) (54%) for the Raman lidar (lambda = 355 nm). An unnoticed loss of sensitivity of the Raman lidar had occurred leading up to AIOP, and we expect better agreement from the recently restored system. Looking at the collective results from six field campaigns conducted since 1996, airborne in situ measurements of sigma(ep)(lambda) tend to be biased slightly low (17% at visible wavelengths) when compared to airborne Sun photometer sigma(ep)(lambda). On the other hand, sigma(ep)(lambda) values derived from lidars tend to have no or positive biases. From the bias differences we conclude that the typical systematic error associated

  10. A study on aerosol extinction-to-backscatter ratio with combination of micro-pulse lidar and MODIS over Hong Kong

    NASA Astrophysics Data System (ADS)

    He, Q. S.; Li, C. C.; Mao, J. T.; Lau, A. K. H.

    2006-04-01

    The aerosol extinction-to-backscatter ratio is an important parameter for inverting LIDAR signals in the LIDAR equation. It is also a complicated function of aerosol microphysical characteristics depending on geographical and meteorological conditions. In this paper, a method to retrieve the column-averaged aerosol extinction-to-backscatter ratio by constraining the aerosol optical depths (AOD) recorded by the Moderate Resolution Imaging Spectroradiometer (MODIS) to the ones measured by a Micro-pulse LIDAR (MPL) is presented. Both measurements were taken between 1 May 2003 and 30 June 2004 over Hong Kong, a coastal city in south China. Simultaneous scattering coefficients measured by a forward scattering visibility sensor are compared with the LIDAR retrieval. The data are then analyzed in terms of monthly and seasonal trends. In addition, the relationships between the extinction-to-backscatter ratio and wind conditions as well as other aerosol microphysical parameters are also presented. The mean aerosol extinction-to-backscatter ratio for the whole period is found to be 28.9±6.1 sr, with the minimum of 12 sr in August 2003 and the maximum of 44 sr in March 2004. The ratio is lower in the summer because of the dominance of oceanic aerosols in association with the prevailing southwesterly monsoon. In contrast, relatively larger ratios are noted in spring and winter because of the increased impact of local and regional industrial pollutants associated with the northerly monsoon. The extended LIDAR measurements over Hong Kong provide not only a more accurate retrieval of aerosol extinction coefficient profiles, but also significant information for air pollution and climate studies in the region.

  11. Secondary organic aerosol from ozone-initiated reactions with terpene-rich household products

    SciTech Connect

    Coleman, Beverly; Coleman, Beverly K.; Lunden, Melissa M.; Destaillats, Hugo; Nazaroff, William W.

    2008-01-01

    We analyzed secondary organic aerosol (SOA) data from a series of small-chamber experiments in which terpene-rich vapors from household products were combined with ozone under conditions analogous to product use indoors. Reagents were introduced into a continuously ventilated 198 L chamber at steady rates. Consistently, at the time of ozone introduction, nucleation occurred exhibiting behavior similar to atmospheric events. The initial nucleation burst and growth was followed by a period in which approximately stable particle levels were established reflecting a balance between new particle formation, condensational growth, and removal by ventilation. Airborne particles were measured with a scanning mobility particle sizer (SMPS, 10 to 400 nm) in every experiment and with an optical particle counter (OPC, 0.1 to 2.0 ?m) in a subset. Parameters for a three-mode lognormal fit to the size distribution at steady state were determined for each experiment. Increasing the supply ozone level increased the steady-state mass concentration and yield of SOA from each product tested. Decreasing the air-exchange rate increased the yield. The steady-state fine-particle mass concentration (PM1.1) ranged from 10 to> 300 mu g m-3 and yields ranged from 5percent to 37percent. Steady-state nucleation rates and SOA mass formation rates were on the order of 10 cm-3 s-1 and 10 mu g m-3 min-1, respectively.

  12. In situ vertical profiles of aerosol extinction, mass, and composition over the SEUS during the SENEX and SEAC4RS studies

    NASA Astrophysics Data System (ADS)

    Wagner, N. L.; Brock, C. A.; Day, D. A.; Diskin, G. S.; Gordon, T. D.; Graus, M.; Holloway, J. S.; Huey, L. G.; Jimenez, J. L.; Lack, D.; Liao, J.; Liu, X.; Markovic, M. Z.; Middlebrook, A. M.; Perring, A. E.; Richardson, M.; Schwarz, J. P.; Warneke, C.; Welti, A.; Wisthaler, A.; Ziemba, L. D.; Murphy, D. M.; Campuzano Jost, P.

    2014-12-01

    Shallow cumulus convection enhances vertical transport of trace gases and aerosol and creates a cloudy transition layer on top of the sub-cloud mixed layer. Two recent studies have proposed that an elevated layer of enhanced organic aerosol over the southeastern United States (SEUS) could explain the discrepancy in the summertime enhancement of aerosol optical depth (AOD) and summertime enhancement of surface measurements of aerosol mass. We investigate the vertical profile of aerosol over the SEUS during the summertime using in situ aircraft-based measurements of aerosol from the SENEX and SEAC4RS studies. During shallow cumulus convection over the SEUS, we found that aerosol and trace gas concentration in the transition layer are diluted by cleaner air from the free troposphere, and the absolute aerosol loading decreases with altitude in the transition layer. However, after normalizing the vertical profiles to the CO boundary layer enhancement to correct for the dilution, the aerosol mass, volume, and extinction relative to the boundary layer CO enhancement is ~20% greater in the transition layer than in the mixed layer. The enhancement of aerosol loading suggests production of aerosol mass in the transition layer, although biomass burning could also be the source of the enhancement. The median composition of the aerosol in the mixed layer is ~70% organics and ~18% sulfate, while it is 65% organics and 23% sulfate in the transition layer. The composition of the aerosol enhancement in the transition layer is roughly equal parts sulfate and organics by mass. The enhancement of aerosol extinction in the transition layer is not sufficient to explain the summertime enhancement of AOD over SEUS.

  13. An Accuracy Assessment of the CALIOP/CALIPSO Version 2/Version 3 Daytime Aerosol Extinction Product Based on a Detailed Multi-Sensor, Multi-Platform Case Study

    NASA Technical Reports Server (NTRS)

    Kacenelenbogen, M.; Vaughan, M. A.; Redemann, J.; Hoff, R. M.; Rogers, R. R.; Ferrare, R. A.; Russell, P. B.; Hostetler, C. A.; Hair, J. W.; Holben, B. N.

    2011-01-01

    The Cloud Aerosol LIdar with Orthogonal Polarization (CALIOP), on board the CALIPSO platform, has measured profiles of total attenuated backscatter coefficient (level 1 products) since June 2006. CALIOP s level 2 products, such as the aerosol backscatter and extinction coefficient profiles, are retrieved using a complex succession of automated algorithms. The goal of this study is to help identify potential shortcomings in the CALIOP version 2 level 2 aerosol extinction product and to illustrate some of the motivation for the changes that have been introduced in the next version of CALIOP data (version 3, released in June 2010). To help illustrate the potential factors contributing to the uncertainty of the CALIOP aerosol extinction retrieval, we focus on a one-day, multi-instrument, multiplatform comparison study during the CALIPSO and Twilight Zone (CATZ) validation campaign on 4 August 2007. On that day, we observe a consistency in the Aerosol Optical Depth (AOD) values recorded by four different instruments (i.e. spaceborne MODerate Imaging Spectroradiometer, MODIS: 0.67 and POLarization and Directionality of Earth s Reflectances, POLDER: 0.58, airborne High Spectral Resolution Lidar, HSRL: 0.52 and ground-based AErosol RObotic NETwork, AERONET: 0.48 to 0.73) while CALIOP AOD is a factor of two lower (0.32 at 532 nm). This case study illustrates the following potential sources of uncertainty in the CALIOP AOD: (i) CALIOP s low signal-to-noise ratio (SNR) leading to the misclassification and/or lack of aerosol layer identification, especially close to the Earth s surface; (ii) the cloud contamination of CALIOP version 2 aerosol backscatter and extinction profiles; (iii) potentially erroneous assumptions of the aerosol extinction-to-backscatter ratio (Sa) used in CALIOP s extinction retrievals; and (iv) calibration coefficient biases in the CALIOP daytime attenuated backscatter coefficient profiles. The use of version 3 CALIOP extinction retrieval for our case

  14. Satellite-Based Evidence of Wavelength-Dependent Aerosol Absorption in Biomass Burning Smoke Inferred from Ozone Monitoring Instrument

    NASA Technical Reports Server (NTRS)

    Jethva, H.; Torres, O.

    2012-01-01

    We provide satellite-based evidence of the spectral dependence of absorption in biomass burning aerosols over South America using near-UV measurements made by the Ozone Monitoring Instrument (OMI) during 2005-2007. In the current near-UV OMI aerosol algorithm (OMAERUV), it is implicitly assumed that the only absorbing component in carbonaceous aerosols is black carbon whose imaginary component of the refractive index is wavelength independent. With this assumption, OMI-derived aerosol optical depth (AOD) is found to be significantly over-estimated compared to that of AERONET at several sites during intense biomass burning events (August-September). Other well-known sources of error affecting the near-UV method of aerosol retrieval do not explain the large observed AOD discrepancies between the satellite and the ground-based observations. A number of studies have revealed strong spectral dependence in carbonaceous aerosol absorption in the near-UV region suggesting the presence of organic carbon in biomass burning generated aerosols. A sensitivity analysis examining the importance of accounting for the presence of wavelength-dependent aerosol absorption in carbonaceous particles in satellite-based remote sensing was carried out in this work. The results convincingly show that the inclusion of spectrally-dependent aerosol absorption in the radiative transfer calculations leads to a more accurate characterization of the atmospheric load of carbonaceous aerosols.

  15. Assesment of aerosol optical depth at UV wavelegths from Microtops II "ozone monitor

    NASA Astrophysics Data System (ADS)

    Gómez-Amo, J. L.; di Sarra, A.; Estellés, V.; Utrillas, M. P.; Martínez-Lozano, J. A.

    2009-04-01

    The aerosol optical depth (AOD) retrieval at ultraviolet spectral region (UV) has been of interest for the last few years, especially due to the important rule that the particles play in the Earth climate modifying the earth-atmosphere energy budget. That is the reason why a great number of methodologies have been developed to obtain AOD, usually by means of instruments aimed to ozone monitoring. Microtops II "ozone meter" is a small hand-held manually operated instrument designed for the measurement of ozone atmospheric columnar content. The instrument operates in five spectral channels centred at 305.5, 312.5, 320.0, 936 and 1020nm wavelengths. The firsts three channels (UV) are used to obtain the ozone content, the 936nm channel is used to water vapour retrieval and the last one permit to obtain the AOD at 1020nm. The aim of this work is to use the UV ozone channels to assess the capability of Microtops II "ozone monitor" to retrieve AOD at 312.5, 305.5 and 320nm. On this way we can improve substantially the performance of Microtops II for the characterization of important components present in the atmosphere using only its own measurements. The methodology used to carry out the AOD retrieval is based on the application of the Beer-Lambert-Bouguer law to the Microtops II UV channels. A very good calibration is needed to apply this kind of methodologies since they show an important dependence on the calibration factors. The AOD is calculated eliminating the ozone contribution (using the ozone content from the combination of 305.5 and 312.5 channels) and the molecular one (Rayleigh). The AOD retrieval has been tested in a 15-days field campaign carried out at Lampedusa Island (35.52°N, 12.63°E, 45m a.s.l.) in the framework of the GAMARF (Ground-based and Airborne Measurments of the Aerosol Radiative Forcing) project. The results obtained during the campaign show, for a background atmospheric situation, AOD values of 0.10 ± 0.03, 0.17 ± 0.03 and 0.05 ± 0.03 at

  16. The capability of satellite borne remote sensors to measure stratospheric trace constituents. Volume 2: Ozone and aerosol related missions

    NASA Technical Reports Server (NTRS)

    Keitz, E. L.

    1978-01-01

    Stratospheric trace constituent measurement requirements are separated into two somewhat overlapping areas. In the first area, it is assumed that the only problem of interest is ozone; its chemistry chain, environmental effects and measurement requirements. In like manner, in the second area it is assumed that the only problem of interest is stratospheric aerosols; their chemistry, effects and measurement requirements.

  17. PULMONARY FUNCTION AND BRONCHIAL REACTIVITY IN HUMAN SUBJECTS WITH EXPOSURE TO OZONE AND RESPIRABLE SULFURIC ACID AEROSOL

    EPA Science Inventory

    A three-year research study was conducted investigating the effects of individual and sequential exposures to ozone and sulfuric acid aerosol on pulmonary function and bronchial reactivity in human subjects. PHASE I: In healthy smokers and nonsmokers exposed for 4 hours to 98 mic...

  18. Ozone and aerosol tropospheric concentrations variability analyzed using the ADRIMED measurements and the WRF and CHIMERE models

    NASA Astrophysics Data System (ADS)

    Menut, L.; Mailler, S.; Siour, G.; Bessagnet, B.; Turquety, S.; Rea, G.; Briant, R.; Mallet, M.; Sciare, J.; Formenti, P.; Meleux, F.

    2015-06-01

    During the months of June and July 2013, over the Euro-Mediterranean area, the ADRIMED (Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) project was dedicated to characterize the ozone and aerosol concentrations in the troposphere. It is first shown that this period was not highly polluted compared to previous summers in this region, with a moderate ozone production, no significant vegetation fire events and several precipitation periods scavenging the aerosol. The period is modeled with the WRF (Weather Research and Forecasting) and CHIMERE models, and their ability to quantify the observed pollution transport events is presented. The CHIMERE model simulating all kinds of sources (anthropogenic, biogenic, mineral dust, vegetation fires); the aerosol speciation, not available with the measurements, is presented: during the whole period, the aerosol was mainly constituted by mineral dust, sea salt and sulfates close to the surface and mainly by mineral dust in the troposphere. Compared to the AERONET (Aerosol Robotic Network) size distribution, it is shown that the model underestimates the coarse mode near mineral dust sources and overestimates the fine mode in the Mediterranean area, highlighting the need to improve the model representation of the aerosol size distribution both during emissions, long-range transport and deposition.

  19. Temperature dependence of bromine activation due to reaction with ozone in a proxy for organic aerosols

    NASA Astrophysics Data System (ADS)

    Edebeli, Jacinta; Ammann, Markus; Gilgen, Anina; Eichler, Anja; Schneebeli, Martin; Bartels-Rausch, Thorsten

    2016-04-01

    The discovery of boundary layer ozone depletion events in the Polar Regions [1] and in the mid-latitudes [2], two areas of very different temperature regimes, begs the question of temperature dependence of reactions responsible for these observations [3]. These ODEs have been attributed to ozone reacting with halides leading to reactive halogens (halogen activation) of which bromide is extensively studied, R1 - R3 [4, 5] (R1 is a multiphase reaction). O3 + Br‑→ O2 + OBr‑ (R1) OBr‑ + H+ ↔ HOBr (R2) HOBr + H+ + Br‑→ Br2 + H2O (R3) Despite extensive studies of ozone-bromide interactions, the temperature dependence of bromine activation is not clear [3]. This limits parameterization of the involved reactions and factors in atmospheric models [3, 6]. Viscosity changes in the matrix (such as organic aerosols) due to temperature have been shown to influence heterogeneous reaction rates and products beyond pure temperature effect [7]. With the application of coated wall flow-tubes, the aim of this study is therefore to investigate the temperature dependence of bromine activation by ozone interaction while attempting to characterize the contributions of the bulk and surface reactions to observed ozone uptake. Citric acid is used in this study as a hygroscopically characterized matrix whose viscosity changes with temperature and humidity. Here, we present reactive ozone uptake measured between 258 and 289 K. The data show high reproducibility. Comparison of measured uptake with modelled bulk uptake at different matrix compositions (and viscosities) indicate that bulk reactive uptake dominates, but there are other factors which still need further consideration in the model. References 1. Barrie, L.A., et al., Nature, 1988. 334: p. 138 - 141. 2. Hebestreit, K., et al., Science, 1999. 283: p. 55-57. 3. Simpson, W.R., et al., Atmospheric Chemistry and Physics, 2007. 7: p. 4375 - 4418. 4. Haag, R.W. and J. Hoigné, Environ Sci Technol, 1983. 17: p. 261-267. 5. Oum

  20. Phase function, backscatter, extinction, and absorption for standard radiation atmosphere and El Chichon aerosol models at visible and near-infrared wavelengths

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.; Suttles, J. T.; Lecroy, S. R.

    1985-01-01

    Tabular values of phase function, Legendre polynominal coefficients, 180 deg backscatter, and extinction cross section are given for eight wavelengths in the atmospheric windows between 0.4 and 2.2 microns. Also included are single scattering albedo, asymmetry factor, and refractive indices. These values are based on Mie theory calculations for the standard rediation atmospheres (continental, maritime, urban, unperturbed stratospheric, volcanic, upper atmospheric, soot, oceanic, dust, and water-soluble) assest measured volcanic aerosols at several time intervals following the El Chichon eruption. Comparisons of extinction to 180 deg backscatter for different aerosol models are presented and related to lidar data.

  1. Impact of human presence on secondary organic aerosols derived from ozone-initiated chemistry in a simulated office environment.

    PubMed

    Fadeyi, Moshood O; Weschler, Charles J; Tham, Kwok W; Wu, Wei Y; Sultan, Zuraimi M

    2013-04-16

    Several studies have documented reductions in indoor ozone levels that occur as a consequence of its reactions with the exposed skin, hair and clothing of human occupants. One would anticipate that consumption of ozone via such reactions would impact co-occurring products derived from ozone's reactions with various indoor pollutants. The present study examines this possibility for secondary organic aerosols (SOA) derived from ozone-initiated chemistry with limonene, a commonly occurring indoor terpene. The experiments were conducted at realistic ozone and limonene concentrations in a 240 m(3) chamber configured to simulate a typical open office environment. During an experiment the chamber was either unoccupied or occupied with 18-20 workers. Ozone and particle levels were continuously monitored using a UV photometric ozone analyzer and a fast mobility particle sizer (FMPS), respectively. Under otherwise identical conditions, when workers were present in the simulated office the ozone concentrations were approximately two-thirds and the SOA mass concentrations were approximately one-half of those measured when the office was unoccupied. This was observed whether new or used filters were present in the air handling system. These results illustrate the importance of accounting for occupancy when estimating human exposure to pollutants in various indoor settings. PMID:23488675

  2. EXTINCTION STUDIES OF PROPANE/AIR COUNTERFLOW DIFFUSION FLAMES: THE EFFECTIVENESS OF AEROSOLS

    EPA Science Inventory

    The fire suppression effectiveness of solid aerosols as suitable halon replacements has examined. Experiments were performed in a counterflow diffusion burner, consisting of two 1 cm i.d. tubes separated by 1 cm. Aerosols were delivered to propane/air flames in the air flow. Both...

  3. Airborne DIAL Ozone and Aerosol Trends Observed at High Latitudes Over North America from February to May 2000

    NASA Technical Reports Server (NTRS)

    Hair, Jonathan W.; Browell, Edward V.; Butler, Carolyn F.; Grant, William B.; DeYoung, Russell J.; Fenn, Marta A.; Brackett, Vince G.; Clayton, Marian B.; Brasseur, Lorraine

    2002-01-01

    Ozone (O3) and aerosol scattering ratio profiles were obtained from airborne lidar measurements on thirty-eight aircraft flights over seven aircraft deployments covering the latitudes of 40 deg.-85 deg.N between 4 February and 23 May 2000 as part of the TOPSE (Tropospheric Ozone Production about the Spring Equinox) field experiment. The remote and in situ O3 measurements were used together to produce a vertically-continuous O3 profile from near the surface to above the tropopause. Ozone, aerosol, and potential vorticity (PV) distributions were used together to identify the presence of pollution plumes and stratospheric intrusions. The number of observed pollution plumes was found to increase into the spring along with a significant increase in aerosol loading. Ozone was found to increase in the middle free troposphere (4-6 km) at high latitudes (60 deg.-85 deg. N) by an average of 4.3 ppbv/mo from about 55 ppbv in early February to over 72 ppbv in mid-May. The average aerosol scattering ratios in the same region increased at an average rate of 0.37/mo from about 0.35 to over 1.7. Ozone and aerosol scattering were highly correlated over entire field experiment. Based on the above results and the observed aircraft in-situ measurements, it was estimated that stratospherically-derived O3 accounted for less than 20% of the observed increase in mid tropospheric O3 at high latitudes. The primary cause of the observed O3 increase was found to be the photochemical production of O3 in pollution plumes.

  4. Estimate of biogenic VOC emissions in Japan and their effects on photochemical formation of ambient ozone and secondary organic aerosol

    NASA Astrophysics Data System (ADS)

    Chatani, Satoru; Matsunaga, Sou N.; Nakatsuka, Seiji

    2015-11-01

    A new gridded database has been developed to estimate the amount of isoprene, monoterpene, and sesquiterpene emitted from all the broadleaf and coniferous trees in Japan with the Model of Emissions of Gases and Aerosols from Nature (MEGAN). This database reflects the vegetation specific to Japan more accurately than existing ones. It estimates much lower isoprene emitted from other vegetation than trees, and higher sesquiterpene emissions mainly emitted from Cryptomeria japonica, which is the most abundant plant type in Japan. Changes in biogenic emissions result in the decrease in ambient ozone and increase in organic aerosol simulated by the air quality simulation over the Tokyo Metropolitan Area in Japan. Although newly estimated biogenic emissions contribute to a better model performance on overestimated ozone and underestimated organic aerosol, they are not a single solution to solve problems associated with the air quality simulation.

  5. Design Of A Novel Open-Path Aerosol Extinction Cavity Ringdown Spectrometer And Initial Data From Deployment At NOAA's Atmospheric Observatory

    NASA Astrophysics Data System (ADS)

    Gordon, T. D.; Wagner, N. L.; Richardson, M.; Law, D. C.; Wolfe, D. E.; Brock, C. A.; Erdesz, F.; Murphy, D. M.

    2014-12-01

    The ability to frame effective climate change policy depends strongly on reducing the uncertainty in aerosol radiative forcing, which is currently nearly as great as best estimates of its magnitude. Achieving this goal will require significant progress in measuring aerosol properties, including aerosol optical depth, single scattering albedo and the effect of relative humidity on these properties for both fine and coarse particles. However both ground- and space-based instruments fail or are highly biased in the presence of clouds, severely limiting quantitative estimates of the radiative effects of aerosols where they are advected over low-level clouds. Moreover, many in situ aerosol measurements exclude the coarse fraction, which can be very important in and downwind of desert regions. By measuring the decay rate of a pulsed laser in an optically resonant cavity, cavity ringdown spectrometers (CRDSs) have been employed successfully in measuring aerosol extinction for particles in relative humidities below 90%. At very high humidities (as found in and near clouds), however, existing CRDSs perform poorly, diverging significantly from theoretical extinction values as humidities approach 100%. The new open-path aerosol extinction CRDS described in this poster measures extinction as aerosol is drawn through the sample cavity directly without inlets or tubing for channeling the flow, which cause particle losses, condensation at high RH and other artifacts. This poster presents the key elements of the new open-path CRDS design as well as comparisons with an earlier generation closed-path CRDS and preliminary data obtained during a field study at the 300 meter tower at NOAA's Boulder Atmospheric Observatory (BAO) in Colorado.

  6. Comparison of one-parameter and two-parameter models of aerosol extinction for experimental data of the arid zone of Kazakhstan

    NASA Astrophysics Data System (ADS)

    Shchelkanov, N. N.

    2015-11-01

    Comparison of four aerosol models is carried out: two one-parameter models for a ground layer of the arid zone of Kazakhstan, two-parameter model for horizontal paths and two-parameter model for horizontal and slant paths. It is shown that the models obtained using the new methods for construction of linear regression and separation of the components allow physically correct retrieval of not only the values of the aerosol extinction coefficients, but also their root mean square deviations.

  7. Combined Laboratory and Modeling Study of the IR Extinction and Visible Light Scattering Properties of Mineral Dust Aerosol

    NASA Astrophysics Data System (ADS)

    Alexander, J. M.; Laskina, O.; Meland, B. S.; Parker, A.; Grassian, V. H.; Young, M. A.; Kleiber, P.

    2011-12-01

    Mineral dust aerosol plays a significant role in the Earth's climate system through the scattering and absorption of both incoming solar radiation in the UV-Visible range and outgoing IR terrestrial radiation. Atmospheric dust particles also serve as sites for cloud nucleation indirectly affecting albedo, and as reactive surfaces for heterogeneous chemistry. Correctly modeling the direct and indirect effects of dust requires accurate information about dust loading, dust composition, size, and shape (CSS) distributions, and aerosol optical (scattering and absorption) properties. The optical properties, however, are strongly dependent on both particle shape and composition, and mineral dust aerosol samples are often complex, inhomogeneous mixtures of particles that may be highly irregular in shape. In this work IR extinction and visible light scattering and polarization profiles are measured for a series of authentic and model dust mixtures including samples of Iowa loess, Arizona road dust, and diatomaceous earth. Laboratory measurements also include particle CSS distributions determined through real-time particle sizing, and various ex situ characterization methods. The experimental data are compared with T-Matrix model simulations based on the measured particle size distributions. Different methods used to infer particle shape and composition distributions are explored and evaluated.

  8. Ozone

    MedlinePlus

    ... Earth's surface. It shields us from the sun's ultraviolet rays. Part of the good ozone layer is ... enough good ozone, people may get too much ultraviolet radiation. This may increase the risk of skin ...

  9. Ozone

    MedlinePlus

    ... reactive form of oxygen. In the upper atmosphere, ozone forms a protective layer that shields us from the sun’s ultraviolet rays. At ground level, ozone is a harmful air pollutant and a primary ...

  10. Investigating the impacts of aviation NOX, SO2 and black carbon emissions on ozone, aerosol and climate.

    NASA Astrophysics Data System (ADS)

    Kapadia, Zarashpe; Borman, Duncan; Spracklen, Dominick; Arnold, Stephen; Mann, Graham; Williams, Paul

    2013-04-01

    Aviation is currently responsible for 3% of global anthropogenic CO2 emissions, but 2-14% of anthropogenic induced warming due to the co-emission of NOX, SO2 and black carbon and formation of contrails. The impact of aviation emissions on ozone and aerosol is uncertain with recent research demonstrating the need to include atmospheric nitrate chemistry. The inclusion of nitrate chemistry may lead to a 20% reduction in aviation induced ozone forcing estimates due to the competition for atmospheric oxidants such as OH . Compounding this, uncertainties relating to the effects of NOx on ozone and methane illustrate the need for refining the understanding of aviation induced impacts. Furthermore the role of aerosol microphysics in controlling the climate impacts of aviation has not yet been explored. Here we use the TOMCAT 3-D chemical transport model coupled to the GLOMAP-mode aerosol microphysics model to quantify the impacts of aviation NOX, SO2 and BC emissions on ozone, aerosol and climate. GLOMAP-mode treats size resolved aerosol using a two-moment modal approach. We evaluate the effects of nitrate processing on the diagnosed impacts of aviation emissions on atmospheric composition including the first assessment of the impact on the global concentrations of cloud condensation nuclei. We investigate interactions between gas-phase oxidant photochemistry and aerosol microphysics in regions influenced by aircraft emissions, using fully-coupled tropospheric chemistry and multi-component aerosol treatment (BC, sulphate, nitrate). Finally, we use a 3-D radiative transfer model to quantify the ozone and aerosol direct and indirect radiative effects of aviation emissions. The work presented here is part of a wider research project which will be the first study to combine aviation NOX, SO2 and black carbon emission in a global size-resolved model which considers atmospheric nitrate chemistry, which will aim to add to the science surrounding present day aviation impacts by

  11. Ozone

    MedlinePlus

    Ozone is a gas. It can be good or bad, depending on where it is. "Good" ozone occurs naturally about 10 to 30 miles above ... the sun's ultraviolet rays. Part of the good ozone layer is gone. Man-made chemicals have destroyed ...

  12. The effects of increasing atmospheric ozone on biogenic monoterpene profiles and the formation of secondary aerosols

    NASA Astrophysics Data System (ADS)

    Pinto, Delia M.; Tiiva, Päivi; Miettinen, Pasi; Joutsensaari, Jorma; Kokkola, Harri; Nerg, Anne-Marja; Laaksonen, Ari; Holopainen, Jarmo K.

    Monoterpenes are biogenic volatile organic compounds (BVOCs) which play an important role in plant adaptation to stresses, atmospheric chemistry, plant-plant and plant-insect interactions. In this study, we determined whether ozonolysis can influence the monoterpenes in the headspace of cabbage. The monoterpenes were mixed with an air-flow enriched with 100, 200 or 400 ppbv of ozone (O 3) in a Teflon chamber. The changes in the monoterpene and O 3 concentrations, and the formation of secondary organic aerosols (SOA) were determined during ozonolysis. Furthermore, the monoterpene reactions with O 3 and OH were modelled using reaction kinetics equations. The results showed that all of the monoterpenes were unequally affected: α-thujene, sabinene and D-limonene were affected to the greatest extend, whereas the 1,8-cineole concentration did not change. In addition, plant monoterpene emissions reduced the O 3 concentration by 12-24%. The SOA formation was dependent on O 3 concentration. At 100 ppbv of O 3, virtually no new particles were formed but clear SOA formation was observed at the higher ozone concentrations. The modelled results showed rather good agreements for α-pinene and 1,8-cineole, whereas the measured concentrations were clearly lower compared to modelled values for sabinene and limonene. In summary, O 3-quenching by monoterpenes occurs beyond the boundary layer of leaves and results in a decreased O 3 concentration, altered monoterpene profiles and SOA formation.

  13. High-Resolution Mass Spectrometric Analysis of Secondary Organic Aerosol Produced by Ozonation of Limonene

    SciTech Connect

    Walser, Maggie L.; Dessiaterik, Yury; Laskin, Julia; Laskin, Alexander; Nizkorodov, Serguei

    2008-02-08

    Secondary organic aerosol (SOA) particles formed from the ozone-initiated oxidation of limonene are characterized by high-resolution electrospray ionization mass spectrometry in both the positive and negative ion modes. The mass spectra reveal a large number of both monomeric (m/z < 300) and oligomeric (m/z > 300) products of oxidation. A combination of high resolving power (m/Δm ~60,000) and Kendrick mass defect analysis makes it possible to unambiguously determine the composition for hundreds of individual compounds in SOA samples. Van Krevelen analysis shows that the SOA compounds are heavily oxidized, with average O:C ratios of 0.43 and 0.50 determined from the positive and negative ion mode spectra, respectively. An extended reaction mechanism for the formation of the first generation SOA molecular components is proposed. The mechanism includes known isomerization and addition reactions of the carbonyl oxide intermediates generated during the ozonation of limonene, and numerous isomerization pathways for alkoxy radicals resulting from the decomposition of unstable carbonyl oxides. The isomerization reactions yield numerous products with a progressively increasing number of alcohol and carbonyl groups, whereas C-C bond scission reactions in alkoxy radicals shorten the carbon chain. Together these reactions yield a large number of isomeric products with broadly distributed masses. A qualitative agreement is found between the number and degree of oxidation of the predicted and measured reaction products in the monomer range.

  14. The study of aerosol and ozone measurements in lower boundary layer with UAV helicopter platform

    NASA Astrophysics Data System (ADS)

    Lin, Po-hsiung; Chen, Wen-nai

    2013-04-01

    This study describes the aerosol and ozone measurement in the lower atmospheric boundary layer of highly polluted region at Kao-hsiung, Taiwan with a small unmanned aerial vehicle (UAV) helicopter platform. This UAV helicopter, modified from Gaui-X7 electronic-power model helicopter with autopilot AHRS (Altitude-Head-Reference System) kit, has fast climb speed up to 700 m height and keeps stable status for atmospheric measurements in five-minute fly leg. Several quick-replaced battery packages are ready on ground for field intensive observation. The payload rack under this UAV helicopter carries a micro-Aethalometer (black carbon concentration), ozone meter, temperature-humidity sensor, barometer and a time-lapse digital camera. The field measurement site closes to Linyuan Petrochemical Industrial Park, where is one of the heavy polluted regions in Taiwan. Balloon-borne Vaisala RS-92 radiosonde and CL31 Lidar Ceilometer are used to provide the background of the atmosphere at the same time. More data analysis measured by UAV helicopter and its potential application will be discussed.

  15. Comparison of Aerosol Backscatter and Extinction Profiles Based on the Earlinet Database and the Single Calculus Chain for Thessaloniki Greece (2001-2014)

    NASA Astrophysics Data System (ADS)

    Voudouri, K.; Siomos, N.; Giannakaki, E.; Amiridis, V.; d'Amico, G.; Balis, D. S.

    2016-06-01

    Aerosol backscatter and extinction coefficient profiles derived by the Single Calculus Chain (SCC) algorithm, which was developed within the European Aerosol Research Lidar Network (EARLINET) are compared with profiles derived by the operational inversion algorithm of Thessaloniki. Measurements performed during the period 2001-2014, that have already been uploaded in the EARLINET database, are considered in this study. The objective of this study is to verify, for the case of Thessaloniki, the consistency of the climatology of the aerosol profiles based on SCC and the EARLINET database data respectively. In this paper we show example comparisons for each lidar product submitted in the official database.

  16. Total Ozone Mapping Spectrometer (TOMS) observations of increases in Asian aerosol in winter from 1979 to 2000

    SciTech Connect

    Massie, Steven T.; Torres, O.; Smith, Steven J.

    2004-12-01

    Emission inventories indicate that the largest increases in SO{sub 2} emissions have occurred in Asia during the last 20 years. By inference, largest increases in aerosol, produced primarily by the conversion of SO{sub 2} to sulfate, should have occurred in Asia during the same time period. Decadal changes in regional aerosol optical depths are calculated by analyzing Total Ozone Mapping Spectrometer (TOMS) vertical aerosol optical depths (converted to 550 nm) from 1979 to 2000 on a 1{sup o} by 1{sup o} global grid. The anthropogenic component of the TOMS aerosol record is maximized by examining the seasonal cycles of desert dust and Boreal fire smoke, and identifying the months of the year for which the desert dust and Boreal fire smoke are least conspicuous. Gobi and Taklimakan desert dust in Asia is prevalent in the TOMS record during spring, and eastern Siberian smoke from Boreal forest fires is prevalent during summer. Aerosol trends are calculated on a regional basis during winter (November-February) to maximize the anthropogenic component of the aerosol record. Large increases in aerosol optical depths between 1979 and 2000 are present over the China coastal plain and the Ganges river basin in India. Aerosol increased by 17% per decade during winter over the China coastal plain, while SO{sub 2} emissions over the same geographical region increased by 33% per decade.

  17. Diurnal and elevational variations in ozone and aerosol concentrations in New Hampshire`s Class-I Airsheds

    SciTech Connect

    Hill, L.B.; Allen, G.A.

    1994-12-31

    Ozone and fine mass aerosol concentrations on New Hampshire`s Mount Washington, situated adjacent to both the Presidential/Dry River and Great Gulf Wilderness Class-I Airsheds, exhibit distinct diurnal and elevational patterns. These patterns are attributed to regional pollutant transport dynamics, nocturnal atmospheric stratification, mountain meteorological phenomena and scavenging. A well-defined planetary boundary layer (PBL) forms at about 1 km elevation at night as demonstrated by nocturnal ozone monitoring along the Mount Washington Auto Road. The PBL provides an effective elevational barrier at night, isolating the valleys from the regionally transported air pollutants present above the mixing layer. During the daytime, the PBL breaks up due to convective processes and katabatic winds resulting from solar heating in the valley. This process creates a diurnal mixing cycle with ozone maxima recorded near mid-day in the adjacent valley. In contrast, fine mass concentrations are higher at the valley site, attributed to local source inputs, and the lack of strong nocturnal scavenging processes, compared with ozone. How aerosol concentrations are related to the PBL and how they are affected by diurnal mixing remains unclear largely due to current sampling methods. Exposure to ozone is generally greater above the treeline in the two airsheds.

  18. Ozone and aerosol distributions over the Amazon Basin during the wet season

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Gregory, G. L.; Harriss, R. C.; Kirchhoff, V. W. J. H.

    1990-01-01

    Results are presented of O3 and aerosol measurements made in the lower troposphere from April 13 through May 10, 1987, as part of the wet season field experiment. Aircraft flights on the NASA Electra were conducted in the vicinity of Manaus, Brazil and between Manaus and the mouth of the Amazon River. Airborne O3 measurements were made in situ and with a lidar system pointed below the aircraft in nadir mode of operation. Data collection and results concerning the distributions of O3 and aerosols observed during the wet season from within the mixed layer to the middle troposphere over the central Amazon basin and between Manaus and Belem are discussed, and these observations are compared to the measurements obtained in the 1985 dry season. Ozone mixing ratio values are found to be lower than those of the 1985 dry season by 6-8 ppbv, indicating a strong removal process near the surface during wet season. It is also found that within the mixed layer O3 levels appeared to be lower over the forest compared to over the ocean.

  19. Imaginary refractive-index effects on desert-aerosol extinction versus backscatter relationships at 351 nm: numerical computations and comparison with Raman lidar measurements.

    PubMed

    Perrone, Maria Rita; Barnaba, Francesca; De Tomasi, Ferdinando; Gobbi, Gian Paolo; Tafuro, Anna Maria

    2004-10-10

    A numerical model is used to investigate the dependence at 351 nm of desert-aerosol extinction and backscatter coefficients on particle imaginary refractive index (mi). Three ranges (-0.005 < or = mi < or = -0.001, -0.01 < or = mi < or = -0.001, and -0.02 < or = mi < or = -0.001) are considered, showing that backscatter coefficients are reduced as /mi/ increases, whereas extinction coefficients are weakly dependent on mi. Numerical results are compared with extinction and backscatter coefficients retrieved by elastic Raman lidar measurements performed during Saharan dust storms over the Mediterranean Sea. The comparison indicates that a range of -0.01 to -0.001 can be representative of Saharan dust aerosols and that the nonsphericity of mineral particles must be considered. PMID:15508611

  20. Validation of aerosol extinction and water vapor profiles from routine Atmospheric Radiation Measurement Climate Research Facility measurements

    SciTech Connect

    Schmid, Beat; Flynn, Connor J.; Newsom, Rob K.; Turner, David D.; Ferrare, Richard; Clayton, Marian F.; Ogren, John A.; Russell, P. B.; Gore, W.; Dominguez, Roseanne

    2009-11-26

    The accuracy with which vertical profiles of aerosol extinction σep(λ) can be retrieved from ARM Climate Research Facility (ACRF) routine measurements was assessed using data from two airborne field campaigns, the ARM Aerosol Intensive Operation Period (AIOP, May 2003), and the Aerosol Lidar Validation Experiment (ALIVE, September 2005). This assessment pertains to the aerosol at its ambient concentration and thermodynamic state (i.e. σep(λ) either free of or corrected for sampling artifacts) and includes the following ACRF routine methods: Raman Lidar, Micro Pulse Lidar (MPL) and in-situ aerosol profiles (IAP) with a small aircraft. Profiles of aerosol optical depth τp(λ), from which the profiles of σep(λ)are derived through vertical differentiation, were measured by the NASA Ames Airborne Tracking 14-channel Sunphotometer (AATS-14); these data were used as truth in this evaluation. The ACRF IAP σep(550 nm) were lower by 16% (during AIOP) and higher by 10% (during ALIVE) when compared to AATS-14. The ACRF MPL σep(523 nm) were higher by 24% (AIOP) and 19%-21% (ALIVE) compared to AATS-14 but the correlation improved significantly during ALIVE. In the AIOP a second MPL operated by NASA showed a smaller positive bias (13%) with respect to AATS-14. The ACRF Raman Lidar σep(355 nm) were higher by 54% (AIOP) and higher by 6% (ALIVE) compared to AATS-14. The large bias in AIOP stemmed from a gradual loss of the sensitivity of the Raman Lidar starting about the end of 2001 going unnoticed until after AIOP. A major refurbishment and upgrade of the instrument and improvements to a data-processing algorithm led to the significant improvement and very small bias in ALIVE. Finally we find that during ALIVE the Raman Lidar water vapor densities ρw are higher by 8% when compared to AATS-14, whereas comparisons between AATS-14 and in-situ measured ρw aboard two different aircraft showed small negative biases (0 to

  1. Implementation of Rotational Raman Channel in Multiwavelength Aerosol Lidar to Improve Measurements of Particle Extinction and Backscattering at 532 NM

    NASA Astrophysics Data System (ADS)

    Veselovskii, Igor; Whiteman, David N.; Korenskiy, Michael; Suvorina, A.; Perez-Ramirez, Daniel

    2016-06-01

    We describe a practical implementation of rotational Raman (RR) measurements in an existing Mie-Raman lidar to obtain measurements of aerosol extinction and backscattering at 532 nm. A 2.3 nm width interference filter was used to select a spectral range characterized by low temperature sensitivity within the anti-Stokes branch of the RR spectrum. Simulations demonstrate that the temperature dependence of the scattering cross section does not exceed 1.0% in the 230-300K range making accurate correction for this dependence quite easy. With this upgrade, the NASA/GSFC multiwavelength Raman lidar has demonstrated useful α532 measurements and was used for regular observations. Examples of lidar measurements and inversion of optical data to the particle microphysics will be given in presentation.

  2. Altitude Differentiated Aerosol Extinction Over Tenerife (North Atlantic Coast) During ACE-2 by Means of Ground and Airborne Photometry and Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Formenti, P.; Elias, T.; Welton, J.; Diaz, J. P.; Exposito, F.; Schmid, B.; Powell, D.; Holben, B. N.; Smirnov, A.; Andreae, M. O.; Devaux, C.; Voss, K.; Lelieveld, J.; Livingston, J. M.; Russell, P. B.; Durkee, P. A.

    2000-01-01

    Retrievals of spectral aerosol optical depths (tau(sub a)) by means of sun photometers have been undertaken in Tenerife (28 deg 16' N, 16 deg 36' W) during ACE-2 (June-July 1997). Five ground-based sites were located at four different altitudes in the marine boundary layer and in the free troposphere, from 0 to 3570 m asl. The goal of the investigation was to provide estimates of the vertical aerosol extinction over the island, both under clean and turbid conditions. Inversion of spectral tau(sub a) allowed to retrieve size distributions, from which the single scattering albedo omega(sub 0) and the asymmetry factor g could be estimated as a function of altitude. These parameters were combined to calculate aerosol forcing in the column. Emphasis is put on episodes of increased turbidity, which were observed at different locations simultaneously, and attributed to outbreaks of mineral dust from North Africa. Differentiation of tau(sub a) as a function of altitude provided the vertical profile of the extinction coefficient sigma(sub e). For dust outbreaks, aerosol extinction is concentrated in two distinct layers above and below the strong subsidence inversion around 1200 m asl. Vertical profiles of tau(sub a) and sigma(sub e) are shown for July 8. In some occasions, vertical profiles are compared to LIDAR observations, performed both at sea level and in the low free troposphere, and to airborne measurements of aerosol optical depths.

  3. Ozone and aerosol distributions over the Amazon basin during the wet season

    SciTech Connect

    Browell, E.V.; Gregory, G.L. ); Harriss, R.C. ); Kirchhoff, V.W.J.H. )

    1990-09-20

    Measurements of ozone (O{sub 3}) and aerosols were made over the tropical rain forest of Brazil during the wet season in April-May 1987 as part of the NASA Global Tropospheric Experiment to study the Amazon boundary layer. Remote and in situ measurements of O{sub 3} and aerosols were made from aircraft on flights over Brazil in the vicinity of Manaus and between Manaus and Belem. Ozonesonde data were also obtained near Manaus. Ozone mixing ratios of <12 ppbv were found in the mixed layer during the wet season with no significant evidence of O{sub 3} produced from biomass burning or photochemistry. These values are lower than those found during the 1985 dry season by 6-8 ppbv. These low O{sub 3} mixing ratios indicate a strong removal process near the surface during the wet season. The region from the mixed layer top to 3 km in altitude had a slowly increasing O{sub 3} profile from 12 to 20 ppbv. On long-range flights between Manaus and Belem, no significant difference was found in the distribution of O{sub 3} above the mixed layer between the inland tropical rain forest and the marine conditions near the coast. Within the mixed layer, there was a definite trend to lower O{sub 3} levels above the forest compared to over the ocean. This reflects the marked difference in the sinks for O{sub 3} over these two regions. The rate of growth of the mixed layer over the rain forest in the wet season was found to be {approximately}9 cm s{sup {minus}1}, which is within the 7-10 cm s{sup {minus}1} range found for the dry season. There was no evidence of the trade wind inversion that was seen during the dry season, and due to frequent precipitation, the background aerosol loading was lower in the wet season than in the dry season.

  4. Optical extinction due to aerosols in the upper haze of Venus: Four years of SOIR/VEX observations from 2006 to 2010

    NASA Astrophysics Data System (ADS)

    Wilquet, Valérie; Drummond, Rachel; Mahieux, Arnaud; Robert, Séverine; Vandaele, Ann Carine; Bertaux, Jean-Loup

    2012-02-01

    The variability of the aerosol loading in the mesosphere of Venus is investigated from a large data set obtained with SOIR, a channel of the SPICAV instrument suite onboard Venus Express. Vertical profiles of the extinction due to light absorption by aerosols are retrieved from a spectral window around 3.0 μm recorded in many solar occultations (˜200) from September 2006 to September 2010. For this period, the continuum of light absorption is analyzed in terms of spatial and temporal variations of the upper haze of Venus. It is shown that there is a high short-term (a few Earth days) and a long-term (˜80 Earth days) variability of the extinction profiles within the data set. Latitudinal dependency of the aerosol loading is presented for the entire period considered and for shorter periods of time as well.

  5. Effects of cloud, aerosol, and ozone on surface spectral Ultraviolet and total irradiance observed in Seoul, Korea

    NASA Astrophysics Data System (ADS)

    Lee, Hana; Kim, Jhoon; Kim, Woogyung; Lee, Yun Gon; Cho, Hi Ku

    2015-04-01

    In recent years, there have been substantial attempts to model the radiative transfer for climatological and biological purposes. However, the incorporation of clouds, aerosols and ozone into the modeling process is one of the difficult tasks due to their variable transmission in both temporal and space domains. In this study we quantify the atmospheric transmissions by clouds, aerosol optical depth (AOD at 320 nm) and total ozone (Ozone) together with all skies in three solar radiation components of the global solar (GS 305-2800nm), total ultraviolet (TUV 290-363nm) and the erythemal weighted ultraviolet (EUV 290-325nm) irradiances with statistical methods using the data at Seoul. The purpose of this study also is to clarify the different characteristics between cloud, AOD and Ozone in the wavelength-dependent solar radiation components. The ozone, EUV and TUV used in this study (March 2003 - February 2014) have been measured with Dobson Spectrophotometer (Beck #124) and Brewer Spectrophotometer (SCI-TEC#148) at Yonsei University, respectively. GS, Cloud Cover (CC) are available from the Korean Meteorological Agency. The measured total (effect of cloud, aerosol, and ozone) transmissions on annual average showed 74%, 76% and 80% of GS, TUV and EUV irradiance, respectively. For the comparison of the measured values with modeled, we have also constructed a multiple linear regression model for the total transmission. The average ratio of measured to modeled total transmission were 0.94, 0.96 and 0.96 with higher measured than modeled value in the three components, respectively, The individual transmission by clouds under the constant AOD and Ozone atmosphere on average showed 68%, 71% and 76% and further the overcast clouds reduced the transmissions to the 45%, 54% and 59% of the clear sky irradiance in the GS, TUV and EUV, respectively. The annual transmissions by AOD showed on average 67%, 70% and 74% and further the high loadings 2.5-4.0 AOD reduced the

  6. AMS Measurements in National Parks of Aerosol Mass, Size and Composition, Comparison with Filter Samples and Correlation with Particle Hygroscopicity and Optical Extinction Properties

    NASA Astrophysics Data System (ADS)

    Alexander, M.; Taylor, N. F.; Collins, D. R.; Kumar, N.; Allen, J.; Newburn, M.; Lowenthal, D. H.; Zielinska, B.

    2011-12-01

    We report a comparison of results from aerosol studies at Great Smoky Mountain National Park (2006), Mt. Rainier National Park (2009) and Acadia National Park (2011), all class I visibility areas associated with IMPROVE (Interagency Monitoring of Protected Visual Environments) sites. This collaborative study was sponsored by the Electric Power Research Institute (EPRI) and was done with the cooperation of the National Park Service and the EPA. The atmospheric aerosol composition in these sites is influenced by a number of anthropogenic as well as biogenic sources, providing a rich environment for fundamental aerosol studies. The primary purpose of these studies was to add state-of-the-art aerosol instrumentation to the standard light extinction and aerosol measurements at the site, used to determine parameters for the IMPROVE light extinction reconstruction equation, adopted by the EPA to estimate light extinction from atmospheric aerosol concentrations and Rayleigh scattering. The combination of these diverse measurements also provides significant insight into fundamental aerosol properties such as aging and radiative forcing. New instrumentation included a quadrupole aerosol mass spectrometer (Aerodyne Q-AMS-Smoky Mountain Study), a high resolution aerosol time-of-flight mass spectrometer (Aerodyne HR-ToF-AMS - Mt. Rainier and Acadia studies) for real time measurements that directly address the relationship between sulfate, nitrate, and OC size and concentration, which is related to cloud and dry gas-to-particle conversion as air masses age during transport, the relationship between WSOC hygroscopic growth and oxygenated organic (OOA) composition, the OCM/OC ratio, and the chemical composition that determines the ambient hygroscopic state. The OCM/OC ratio and organic water uptake was addressed with high-volume and medium volume PM2.5 aerosol samples. Aerosols were collected daily on Teflon coated glass fiber filters (TGFF) in four high-volume PM2.5 samplers

  7. LC-MS analysis of aerosol particles from the oxidation of α-pinene by ozone and OH-radicals

    NASA Astrophysics Data System (ADS)

    Winterhalter, R.; van Dingenen, R.; Larsen, B. R.; Jensen, N. R.; Hjorth, J.

    2003-01-01

    The time resolved chemical composition of aerosol particles, formed by the oxidation of alpha-pinene has been investigated by liquid chromatography/mass spectrometry (LC-MS) using negative and positive ionisation methods (ESI(-) and APCI(+)). The experiments were performed at the EUPHORE facility in Valencia (Spain) under various experimental conditions, including dark ozone reactions, photosmog experiments with low NOx mixing ratios and reaction with OH radicals in the absence of NOx (H2O2-photolysis). Particles were sampled on PTFE f ilters at different stages of the reaction and extracted with methanol. The predominant products from alpha-pinene in the particulate phase are cis-pinic acid, cis-pinonic acid and hydroxy-pinonic acid isomers. Another major compound with molecular weight 172 was detected, possibly a hydroxy-carboxylic acid. These major compounds account for 50% to 80% of the identified aerosol products, depending on the time of sampling and type of experiment. In addition, more than 20 different products have been detected and structures have been tentatively assigned based on their molecular weight and responses to the different ionisation modes. The different experiments performed showed that the aerosol formation is mainly caused by the ozonolysis reaction. The highest aerosol yields were observed in the dark ozone experiments, for which also the highest ratios of mass of identified products to the formed aerosol mass were found (30% to 50%, assuming a density of 1 g cm-3).

  8. Importing ozone precursors and aerosols to the North American free troposphere: An analysis of peroxyacetyl nitrate and aerosol observations at Mount Bachelor

    NASA Astrophysics Data System (ADS)

    Fischer, Emily V.

    Exposure to aerosols and ozone poses a health threat to a large portion of the U.S. population. Domestic sources and a global background burden both contribute to ambient concentrations, and East Asia is currently a fast growing air pollution source. This dissertation presents results from two projects, and in each case observations from the Mount Bachelor Observatory (MBO, 43.980 N, 121.69° W; 2.7 km amsl) play a central role in the analysis. The first component of this dissertation presents an analysis of the first multi-year springtime measurements of peroxyacetyl nitrate (PAN) in the free troposphere over the Pacific Northwest. The measurements were made by gas chromatography with electron capture detector during spring 2008, 2009, and 2010. Springtime mean PAN mixing ratios at MBO varied from 100 pptv to 152 pptv. The observed relationship between PAN and 03 in a descending Asian air mass was used to derive an ozone production efficiency of 51-73 mol mol-1. I combined the observed variability in PAN and ozone at MBO with a range of trends to determine the observational requirements for trend detection. If springtime PAN mixing ratios increase at a rate of 4% per year due to rising Asian emissions, we would detect a trend with 13 years of measurements. If the corresponding trend in ozone is 1% per year, the trend in ozone will be detected on approximately the same timescale. The second component of this dissertation addresses the physical evolution of Asian aerosols and their impact on U.S. air quality. I showed that approximately 50% of the interannual variability in springtime average PM2.5 in remote areas of the U.S. Pacific Northwest can be explained by changes in Asian dust emissions. Next I identified 7 plumes of Asian origin within observations of sub --microm aerosol scattering and absorption from MBO. The average sub-microm scattering Angstrom exponent for the plumes was significantly larger than the same parameter observed closer to Asia, suggesting

  9. Hygroscopic properties and extinction of aerosol particles at ambient relative humidity in South-Eastern China

    NASA Astrophysics Data System (ADS)

    Eichler, H.; Cheng, Y. F.; Birmili, W.; Nowak, A.; Wiedensohler, A.; Brüggemann, E.; Gnauk, T.; Herrmann, H.; Althausen, D.; Ansmann, A.; Engelmann, R.; Tesche, M.; Wendisch, M.; Zhang, Y. H.; Hu, M.; Liu, S.; Zeng, L. M.

    During the "Program of Regional Integrated Experiments of Air Quality over Pearl River Delta 2004 (PRIDE-PRD2004)" hygroscopic properties of particles in the diameter range 22 nm to 10μm were determined. For that purpose, a Humidifying Differential Mobility Particle Sizer (H-DMPS) and a Micro-Orifice Uniform Deposition Impactor (MOUDI) were operated. The derived size-dependent particle hygroscopic growth factors were interpolated to ambient relative humidity (RH) and used to calculate the particle number size distributions (PNSDs) at ambient conditions. A comparison between the modeled particle extinction coefficients (σ) and those observed with a Raman lidar was made. It is shown that the particle extinction coefficient ( σext) at ambient RH can be properly estimated with Mie-model calculations based on the in situ physico-chemical measurements of dry and humidified PNSD and chemical composition.

  10. Aerosol extinction and absorption in Evora, Portugal, during the European 2003 summer heat wave

    NASA Astrophysics Data System (ADS)

    Elias, Thierry G.; Silva, Ana M.; Figueira, Maria J.; Belo, Nuno; Pereira, Sergio; Formenti, Paola; Helas, Gunter

    2004-11-01

    Aerosol optical properties are retrieved from measurements acquired during the 2003 summer at the new AERONET station of Evora, Portugal, with a sun/sky photometer, a fluxmeter and a nephelometer. Aerosol optical thickness (aot) derived at several wavelengths shows that an exceptionally long turbid event occurred in July-August. Desert dust particles transported from North Africa increased aot at 873 nm (aot873) to the value of 0.27 with an Ångstrom exponent αC=0.5. Emissions from forest fires in The Iberic peninsula affected Evora since the end of the dust episode, with aot441 reaching 0.81 and aC=1.8. The aerosol scattering coefficient measured at surface level shows that desert dust does not reach the surface level at Evora while the forest fire emissions were uniformly distributed over the atmospheric column. Sky-radiance and flux measurements agree in retrieval of the aerosol single scattering albedo (assa) at several wavelengths. A large absorption rate is found with a high spectral dependence for desert dust particles (assa441=0.86 and ass873=0.93) and with a flat spectral dependence during the forest fires emission episode (assa441=0.88 and assa873=0.87). All measurements as well as back-trajectory calculations indicate mixture of particles during the desert dust.

  11. Certain Results of Measurements of Characteristics of Stratospheric Aerosol Layer and Total Ozone Content at Siberian Lidar Station in Tomsk

    NASA Astrophysics Data System (ADS)

    Nevzorov, Aleksey; Bazhenov, Oleg; Burlakov, Vladimir; Dolgii, Sergey

    2016-06-01

    We consider the results of long-term remote optical monitoring, obtained at the Siberian Lidar Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences in Tomsk (56.5°N, 85.0°E). The scattering characteristics of stratospheric aerosol layer, obtained according to data of lidar measurements since 1986, are presented. We analyze the trends of changes in the total ozone (TO) content over Tomsk for the period 1996-2013 according to data of spectrophotometric measurements with employment of Total Ozone Mapping Spectrometer (TOMS) data for the period 1979-1994. We determined the periods of elevated content of stratospheric aerosol over Tomsk aftera series of explosive eruptions of volcanoes of Pacific Ring of Fire and Iceland in 2006-2011. Since the second half of 1990s, we record an increasing TO trend, equaling 0.65 DU/yr for the period 1996-2013.

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

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  13. Ozone reactivity of biogenic volatile organic compound (BVOC) emissions during the Southeast Oxidant and Aerosol Study (SOAS)

    NASA Astrophysics Data System (ADS)

    Park, J.; Guenther, A. B.; Helmig, D.

    2013-12-01

    Recent studies on atmospheric chemistry in the forest environment showed that the total reactivity by biogenic volatile organic compound (BVOC) emission is still not well understood. During summer 2013, an intensive field campaign (Southeast Oxidant and Aerosol Study - SOAS) took place in Alabama, U.S.A. In this study, an ozone reactivity measurement system (ORMS) was deployed for the direct determination of the reactivity of foliage emissions. The ORMS is a newly developed measurement approach, in which a known amount of ozone is added to the ozone-free air sample stream, with the ORMS measuring ozone concentration difference between before and after a glass flask flow tube reaction vessel (2-3 minutes of residence time). Emissions were also collected onto adsorbent cartridges to investigate the discrepancy between total ozone reactivity observation and reactivity calculated from identified BVOC. Leaf and canopy level experiments were conducted by deploying branch enclosures on the three dominant tree species at the site (i.e. liquidambar, white oak, loblolly pine) and by sampling ambient air above the forest canopy. For the branch enclosure experiments, BVOC emissions were sampled from a 70 L Teflon bag enclosure, purged with air scrubbed for ozone, nitrogen oxides. Each branch experiment was performed for 3-5 days to collect at least two full diurnal cycle data. In addition, BVOCs were sampled using glass tube cartridges for 2 hours during daytime and 3 - 4 hours at night. During the last week of campaign, the inlet for the ORMS was installed on the top of scaffolding tower (~30m height). The ozone loss in the reactor showed distinct diurnal cycle for all three tree species investigated, and ozone reactivity followed patterns of temperature and light intensity.

  14. Effect of aerosols on the estimation of total ozone in an atmospheric column from the measurements of its ultraviolet radiance

    NASA Technical Reports Server (NTRS)

    Dave, J. V.

    1978-01-01

    The problem of estimating the total ozone amount of an atmospheric column in the presence of stratospheric and tropospheric aerosols is studied by means of simulated spectral measurements for the five-wavelength Nimbus 4 BUV configuration and the six-wavelength Nimbus G TOMS configuration, and by analyzing such measurements with appropriate total ozone estimation procedures. The simulated spectral measurements were generated for forty different atmospheric models arrived at by varying the total ozone content and various aerosol parameters. A total of ten different values of the solar zenith angle and eight different values of the Lambert reflectivity of the underlying surface were used. It was found that the values of total ozone in an atmospheric column estimated by the five-wavelength procedure can be in error by about + or -2% as a result of particulate contamination encountered in the terrestrial atmosphere under average conditions. Errors due to tropospheric particulate contamination can be reduced significantly by taking appropriate advantage of the additional spectral measurement offered by the Nimbus G TOMS instrument.

  15. Reactive uptake of ozone by proxies for organic aerosols: Surface-bound and gas-phase products

    NASA Astrophysics Data System (ADS)

    Thomas, Elan R.; Frost, Gregory J.; Rudich, Yinon

    2001-02-01

    Gas-phase and surface-bound products were determined for the reaction of ozone with self assembled monolayers of alkanes and terminal alkenes serving as proxies for atmospheric organic aerosols. The organic surfaces were characterized using infrared (IR) spectroscopy (direct absorption and attenuated total reflection) as well as contact angle measurements with water before and after the reaction with ozone. The contact angle of the organic surfaces was reduced by ˜20° owing to the reaction. Following the reaction, IR absorption due to the presence of carbonyls and carboxylic acids was observed on the surface. Gas-phase products were determined using infrared spectroscopy immediately above the reaction surface. Under dry conditions, gas-phase formaldehyde yields of 0.5±0.1 for organic monolayers of allyltrichlorosilane (C3=) and octenyltrichlorosilane (C8=) terminal alkenes were observed, in good agreement with the yields observed for gas phase ozonolysis of terminal alkenes. Surfaces of n-octane (C8) as well as processed alkene surfaces were nonreactive toward ozone. The reaction mechanism of ozone with the surface alkenes is discussed. Finally, the possible implications for the chemistry of organic aerosols are discussed and studied using a box model and realistic atmospheric scenarios.

  16. Field test of a new instrument to measure UV/Vis (300-700 nm) ambient aerosol extinction spectra in Colorado during DISCOVER-AQ

    NASA Astrophysics Data System (ADS)

    Jordan, C. E.; Anderson, B. E.; Beyersdorf, A. J.; Dibb, J. E.; Greenslade, M. E.; Martin, R.; Scheuer, E. M.; Shook, M.; Thornhill, K. L., II; Troop, D.; Winstead, E.; Ziemba, L. D.

    2014-12-01

    An optical instrument has been developed to investigate aerosol extinction spectra in the ambient atmosphere. Based on a White-type cell design and using a differential optical approach, aerosol extinction spectra over the 300-700 nm ultraviolet and visible (UV/Vis) wavelength range are obtained. Laboratory tests conducted at NASA Langley Research Center (NASA LaRC) in March 2014 showed good agreement with Cavity Attenuated Phase Shift (CAPS PMex, Aerodyne Research) extinction measurements (at 450, 530, and 630 nm) for a variety of aerosols, e.g., scatterers such as polystyrene latex spheres and ammonium sulfate; absorbers such as dust (including pigmented minerals), smoke (generated in a miniCAST burning propane) and laboratory smoke analogs (e.g., fullerene soot and aquadag). The instrument was field tested in Colorado in July and August 2014 aboard the NASA mobile laboratory at various ground sites during the DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) field campaign. A description of the instrument, results from the laboratory tests, and summer field data will be presented. The instrument provides a new tool for probing in situ aerosol optical properties that may help inform remote sensing approaches well into the UV range.

  17. Ozone loss in the lower stratosphere over the United States in 1992-1993: Evidence for heterogeneous chemistry on the Pinatubo aerosol

    NASA Technical Reports Server (NTRS)

    Hofmann, D. J.; Oltmans, S. J.; Komhyr, W. D.; Harris, J. M.; Lathrop, J. A.; Langford, A. O.; Deshler, T.; Johnson, B. J.; Torres, A.; Matthews, W. A.

    1994-01-01

    Ozone profiles obtained at Boulder, Colorado and Wallops Island, Virginia indicate that ozone was about 25% below normal during the winter and spring of 1992-93 in the 12-22 km region. This large ozone reduction in the lower stratosphere, though sometimes partially compensated by higher than normal ozone above 24 km, was responsible for the low total column ozone values observed across the United States during this period. Normal temperatures throughout the low ozone region suggest that transport-related effects are probably not the most important cause of the ozone deficits. This region of low ozone at Boulder corresponds closely with the location of the enhanced H2SO4/H2O aerosol from the Pinatubo eruption of 1991 as measured near Boulder and at Laramie, Wyoming. Trajectory analyses suggest that except at low altitudes in spring, air parcels on the days of the ozone measurements generally arrived at Boulder from higher latitude, although seldom higher than 60 deg N, and hence may have been subjected to heterogeneous chemical processing on the surface of Pinatubo aerosol droplets resulting in chlorine-catalyzed ozone destruction, a process which is believed to be more effective under the lower winter temperatures and sunlight levels of higher latitudes.

  18. Ozone loss in the lower stratosphere over the United States in 1992-1993: Evidence for heterogeneous chemistry on the Pinatubo aerosol

    SciTech Connect

    Hofmann, D.J.; Oltmans, S.J.; Harris, J.M.; Lathrop, J.A. ); Komhyr, W.D. Univ. of Colorado, Boulder, CO ); Langford, A.O. ); Deshler, T.; Johnson, B.J. ); Torres, A. ); Matthews, W.A. )

    1994-01-01

    Ozone profiles obtained at Boulder, Colorado and Wallops Island, Virginia indicate that ozone was about 25% below normal during the winter and spring of 1992-93 in the 12-22 km region. This large ozone reduction in the lower stratosphere, though sometimes partially compensated by higher than normal ozone above 24 km, was responsible for the low total column ozone values observed across the United States during this period. Normal temperatures throughout the low ozone region suggest that transport-related effects are probably not the most important cause of the ozone deficits. The region of low ozone at Boulder corresponds closely with the location of the enhanced H[sub 2]SO[sub 4]/H[sub 2]O aerosol from the Pinatubo eruption of 1991 as measured near Boulder and at Laramie, Wyoming. Trajectory analyses suggest that except at low altitudes in spring, air parcels on the days of the ozone measurements generally arrived at Boulder from higher latitude, although seldom higher than 60[degrees]N, and hence may have been subjected to heterogeneous chemical processing on the surface of Pinatubo aerosol droplets resulting in chlorine-catalyzed ozone destruction, a process which is believed to be more effective under the lower winter temperatures and sunlight levels of higher latitudes. 21 refs., 4 figs., 5 tabs.

  19. ozone loss in the lower stratosphere over the United States in 1992-1993: Evidence for heterogeneous chemistry on the Pinatubo aerosol

    NASA Astrophysics Data System (ADS)

    Hofmann, D. J.; Oltmans, S. J.; Komhyr, W. D.; Harris, J. M.; Lathrop, J. A.; Langford, A. O.; Deshler, T.; Johnson, B. J.; Torres, A.; Matthews, W. A.

    1994-01-01

    Ozone profiles obtained at Boulder, Colorado and Wallops Island, Virginia indicate that ozone was about 25% below normal during the winter and spring of 1992-93 in the 12-22 km region. This large ozone reduction in the lower stratosphere, though sometimes partially compensated by higher than normal ozone above 24 km, was responsible for the low total column ozone values observed across the United States during this period. Normal temperatures throughout the low ozone region suggest that transport-related effects are probably not the most important cause of the ozone deficits. The region of low ozone at Boulder corresponds closely with the location of the enhanced H2SO4/H2O aerosol from the Pinatubo eruption of 1991 as measured near Boulder and at Laramie, Wyoming. Trajectory analyses suggest that except at low altitudes in spring, air parcels on the days of the ozone measurements generally arrived at Boulder from higher latitude, although seldom higher than 60°N, and hence may have been subjected to heterogeneous chemical processing on the surface of Pinatubo aerosol droplets resulting in chlorine-catalyzed ozone destruction, a process which is believed to be more effective under the lower winter temperatures and sunlight levels of higher latitudes.

  20. Surface ozone concentration and its behaviour with aerosols in the northwestern Himalaya, India

    NASA Astrophysics Data System (ADS)

    Sharma, Priyanka; Kuniyal, Jagdish Chandra; Chand, Kesar; Guleria, Raj Paul; Dhyani, Pitamber Prasad; Chauhan, Chetan

    2013-06-01

    Surface ozone (O3), black carbon (BC) concentration and their relationship were established with PM10 and PM2.5 mass concentration at Mohal (31.9°N, 77.12°E, 1154 m amsl), a semi-urban site, in the Kullu valley of the northwestern part of the Indian Himalaya during January to December, 2010. O3 showed highest diurnal variation (84 ppb) during daytime and lowest (10 ppb) during late evening as well as early morning hours. The maximum concentration of O3 during summer was influenced by meteorological parameters, high insolation and backward airmass trajectories with transported pollutants. Rate of increase of O3 was observed as high as 2.92 ppb h-1 in October, followed by 2.73 ppb h-1 in March and 2.71 ppb h-1 in May. However, it was low 1.89 ppb h-1 in February. Monthly average concentration of O3 showed distinct seasonal variations with maximum in summer (55.9 ± 9.3 ppb in May) and minimum in winter (30.0 ± 6.2 ppb in January). Most of the O3 episodes were observed in summer during fair weather conditions like high solar flux (480-500 W m-2), relatively high temperature (22-24 °C) and negligible rainfall. By applying backward trajectory Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, the origin of the airmasses contributing to the background O3 concentration was investigated. O3 showed negative correlation with BC (r = -0.42). BC contributed 10-20% and 14-42% to the total aerosol mass concentration of PM10 and PM2.5 respectively which showed positive correlation (r = 0.65) with PM10 as well as PM2.5 aerosol mass concentration.

  1. Carboxylic acids in secondary aerosols from oxidation of cyclic monoterpenes by ozone

    SciTech Connect

    Glasius, M.; Lahaniati, M.; Calogirou, A.; Di Bella, D.; Jensen, N.R.; Hjorth, J.; Kotzias, D.; Larsen, B.R.

    2000-03-15

    A series of smog chamber experiments have been conducted in which five cyclic monoterpenes were oxidized by ozone. The evolved secondary aerosol was analyzed by GC-MS and HPLC-MS for nonvolatile polar oxidation products with emphasis on the identification of carboxylic acids. Three classes of compounds were determined at concentration levels corresponding to low percentage molar yields: i.e., dicarboxylic acids, oxocarboxylic acids, and hydroxyketocarboxylic acids. Carboxylic acids are highly polar and have lower vapor pressures than their corresponding aldehydes and may thus play an important role in secondary organic aerosol formation processes. The most abundant carboxylic acids were the following: cis-pinic acid AB1(cis-3-carboxy-2,2-dimethylcyclobutylethanoic acid) from {alpha} and {beta}-pinene; cis-pinonic acid A3 (cis-3-acetyl-2,2-dimethylcyclobutylethanoic acid) and cis-10-hydroxypinonic acid Ab6 (cis-2,2-dimethyl-3-hydroxyacetylcyclobutyl-ethanoic acid) from {alpha}-pinene and {beta}-pinene; cis-3-caric acid C1 (cis-2,2-dimethyl-1,3-cyclopropyldiethanoic acid), cis-3-caronic acid C3 (2,2-dimethyl-3-(2-oxopropyl)cyclopropanylethanoic acid), and cis-10-hydroxy-3-caronic acid C6 (cis-2,2-dimethyl-3(hydroxy-2-oxopropyl)cyclopropanylethanoic acid) from 3-carene; cis-sabinic acid S1 (cis-2-carboxy-1-isopropylcyclopropylethanoic acid) from sabinene; limonic acid L1 (3-isopropenylhexanedioic acid), limononic acid L3 (3-isopropenyl-6-oxo-heptanoic acid), 7-hydroxy-limononic acid L6 (3-isopropenyl-7-hydroxy-6-oxoheptanoic acid), and 7-hydroxylimononic acid Lg{prime} (7-hydroxy-3-isopropenyl-6-oxoheptanoic acid) from limonene.

  2. Quantifying VOC-Reaction Tracers, Ozone Production, and Continuing Aerosol Production Rates in Urban and Far-Downwind Atmospheres

    NASA Technical Reports Server (NTRS)

    Chatfield, Robert; Ren, X.; Brune, W.; Fried, A.; Schwab, J.

    2008-01-01

    We have found a surprisingly informative decomposition of the complex question of smoggy ozone production (basically, [HO2] in a more locally determined field of [NO]) in the process of linked investigations of modestly smoggy Eastern North America (by NASA aircraft, July 2004) and rather polluted Flushing, NYC (Queens College, July, 2001). In both rural and very polluted situations, we find that a simple contour graph parameterization of the local principal ozone production rate can be estimated using only the variables [NO] and j(sub rads) [HCHO]: Po(O3) = c (j(sub rads) [HCHO])(sup a) [HCHO](sup b). Here j(sub rads) is the photolysis of HCHO to radicals, presumably capturing many harder-UV photolytic processes and the principle ozone production is that due to HO2; mechanisms suggest that ozone production due to RO2 is closely correlated, often suggesting a limited range of different proportionality factors. The method immediately suggests a local interpretation for concepts of VOC limitation and NOx limitation. We believe that the product j(sub rads) [HCHO] guages the oxidation rate of observed VOC mixtures in a way that also provides [HO2] useful for the principle ozone production rate k [HO2] [NO], and indeed, all ozone chemical production. The success of the method suggests that dominant urban primary-HCHO sources may transition to secondary plume-HCHO sources in a convenient way. Are there other, simple, near-terminal oxidized VOC's which help guage ozone production and aerosol particle formation? Regarding particles, we report on, to the extent NASA Research resources allow, on appealing relationships between far-downwind (Atlantic PBL) HCHO and very fine aerosol (including sulfate. Since j(sub rads) [HCHO] provides a time-scale, we may understand distant-plume particle production in a more quantitative manner. Additionally we report on a statistical search in the nearer field for relationships between glyoxals (important near-terminal aromatic and isoprene

  3. Nanostructured Polyphase Catalysts Based on the Solid Component of Welding Aerosol for Ozone Decomposition.

    PubMed

    Rakitskaya, Tatyana; Truba, Alla; Ennan, Alim; Volkova, Vitaliya

    2015-12-01

    Samples of the solid component of welding aerosols (SCWAs) were obtained as a result of steel welding by ANO-4, TsL‑11, and UONI13/55 electrodes of Ukrainian manufacture. The phase compositions of the samples, both freshly prepared (FP) and modified (M) by water treatment at 60 °C, were studied by X-ray phase analysis and IR spectroscopy. All samples contain magnetite demonstrating its reflex at 2θ ~ 35° characteristic of cubic spinel as well as manganochromite and iron oxides. FP SCWA-TsL and FP SCWA-UONI contain such phases as СaF2, water-soluble fluorides, chromates, and carbonates of alkali metals. After modification of the SCWA samples, water-soluble phases in their composition are undetectable. The size of magnetite nanoparticles varies from 15 to 68 nm depending on the chemical composition of electrodes under study. IR spectral investigations confirm the polyphase composition of the SCWAs. As to IR spectra, the biggest differences are apparent in the regions of deformation vibrations of M-O-H bonds and stretching vibrations of M-O bonds (M-Fe, Cr). The catalytic activity of the SCWAs in the reaction of ozone decomposition decreases in the order SCWA-ANO > SCWA-UONI > SCWA-TsL corresponding to the decrease in the content of catalytically active phases in their compositions. PMID:26646686

  4. Nanostructured Polyphase Catalysts Based on the Solid Component of Welding Aerosol for Ozone Decomposition

    NASA Astrophysics Data System (ADS)

    Rakitskaya, Tatyana; Truba, Alla; Ennan, Alim; Volkova, Vitaliya

    2015-12-01

    Samples of the solid component of welding aerosols (SCWAs) were obtained as a result of steel welding by ANO-4, TsL-11, and UONI13/55 electrodes of Ukrainian manufacture. The phase compositions of the samples, both freshly prepared (FP) and modified (M) by water treatment at 60 °C, were studied by X-ray phase analysis and IR spectroscopy. All samples contain magnetite demonstrating its reflex at 2 θ ~ 35° characteristic of cubic spinel as well as manganochromite and iron oxides. FP SCWA-TsL and FP SCWA-UONI contain such phases as CaF2, water-soluble fluorides, chromates, and carbonates of alkali metals. After modification of the SCWA samples, water-soluble phases in their composition are undetectable. The size of magnetite nanoparticles varies from 15 to 68 nm depending on the chemical composition of electrodes under study. IR spectral investigations confirm the polyphase composition of the SCWAs. As to IR spectra, the biggest differences are apparent in the regions of deformation vibrations of M-O-H bonds and stretching vibrations of M-O bonds (M-Fe, Cr). The catalytic activity of the SCWAs in the reaction of ozone decomposition decreases in the order SCWA-ANO > SCWA-UONI > SCWA-TsL corresponding to the decrease in the content of catalytically active phases in their compositions.

  5. Characterizing the Vertical Profile of Aerosol Particle Extinction and Linear Depolarization over Southeast Asia and the Maritime Continent: The 2007-2009 View from CALIOP

    NASA Technical Reports Server (NTRS)

    Campbell, James R.; Reid, Jeffrey S.; Westphal, Douglas L.; Zhang, Jianglong; Tackett, Jason L.; Chew, Boon Ning; Welton, Ellsworth J.; Shimizu, Atsushi; Sugimoto, Nobuo; Aoki, Kazuma; Winker, David M.

    2012-01-01

    Vertical profiles of 0.532 µm aerosol particle extinction coefficient and linear volume depolarization ratio are described for Southeast Asia and the Maritime Continent. Quality-screened and cloud-cleared Version 3.01 Level 2 NASA Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) 5-km Aerosol Profile datasets are analyzed from 2007 to 2009. Numerical simulations from the U.S. Naval Aerosol Analysis and Predictive System (NAAPS), featuring two-dimensional variational assimilation of NASA Moderate Resolution Imaging Spectroradiometer and Multi-angle Imaging Spectro- Radiometer quality-assured datasets, combined with regional ground-based lidar measurements, are considered for assessing CALIOP retrieval performance, identifying bias, and evaluating regional representativeness. CALIOP retrievals of aerosol particle extinction coefficient and aerosol optical depth (AOD) are high over land and low over open waters relative to NAAPS (0.412/0.312 over land for all data points inclusive, 0.310/0.235 when the per bin average is used and each is treated as single data points; 0.102/0.151 and 0.086/0.124, respectively, over ocean). Regional means, however, are very similar (0.180/0.193 for all data points and 0.155/0.159 when averaged per normalized bin), as the two factors offset one another. The land/ocean offset is investigated, and discrepancies attributed to interpretation of particle composition and a-priori assignment of the extinction-to-backscatter ratio ("lidar ratio") necessary for retrieving the extinction coefficient from CALIOP signals. Over land, NAAPS indicates more dust present than CALIOP algorithms are identifying, indicating a likely assignment of a higher lidar ratio representative of more absorptive particles. NAAPS resolvesmore smoke overwater than identified with CALIOP, indicating likely usage of a lidar ratio characteristic of less absorptive particles to be applied that biases low AOD there. Over open waters except within the Bay of Bengal

  6. 1984-1995 Evolution of Stratospheric Aerosol Size, Surface Area, and Volume Derived by Combining SAGE II and CLAES Extinction Measurements

    NASA Technical Reports Server (NTRS)

    Russell, Philip B.; Bauman, Jill J.

    2000-01-01

    This SAGE II Science Team task focuses on the development of a multi-wavelength, multi- sensor Look-Up-Table (LUT) algorithm for retrieving information about stratospheric aerosols from global satellite-based observations of particulate extinction. The LUT algorithm combines the 4-wavelength SAGE II extinction measurements (0.385 <= lambda <= 1.02 microns) with the 7.96 micron and 12.82 micron extinction measurements from the Cryogenic Limb Array Etalon Spectrometer (CLAES) instrument, thus increasing the information content available from either sensor alone. The algorithm uses the SAGE II/CLAES composite spectra in month-latitude-altitude bins to retrieve values and uncertainties of particle effective radius R(sub eff), surface area S, volume V and size distribution width sigma(sub g).

  7. In-situ characterisation of aerosol and gases (SO2, HCl, ozone) in Mt Etna volcano plume

    NASA Astrophysics Data System (ADS)

    Roberts, Tjarda; Vignelles, Damien; Giudice, Gaetano; Liuzzo, Marco; Aiuppa, Alessandro; Chartier, Michel; Coute, Benoit; Lurton, Thibaut; Renard, Jean-Baptiste

    2014-05-01

    We present findings from a measurement campaign that deployed a range of in-situ real-time atmospheric measurement techniques to characterise aerosols and gases in Mt Etna plume in October 2013. The LOAC (Light Optical Aerosol Counter) instrument for size-resolved particle measurements was deployed alongside two Multi-Gas instruments (measuring SO2, H2S, HCl, CO2) and an ozone sensor. Measurements were performed at the summit craters (in cloudy- and non-cloudy conditions) and in grounding downwind plume on the volcano flank. These high frequency measurements (acid gases: 1 to 0.1 Hz, aerosol: 0.1 Hz) provide a detailed in-situ dataset for time-resolved plume characterisation and volcano monitoring. The LOAC measurement of sized-resolved aerosol (over a 0.2 to 50 µm particle diameter range) alongside SO2 (10's ppbv to 10's ppmv) provides a valuable dataset for determining the volcanic aerosol volume and surface area to SO2 ratios. These parameters are presently poorly defined but are important for atmospheric models of the reactive halogen chemistry that occurs on volcanic aerosol surfaces to convert volcanic HBr into reactive bromine, including BrO. The LOAC's patented optical design can also provide insights into particle properties. The two Multi-Gas SO2 time-series show good agreement, detecting co-varying plume fluctuations in the downwind plume, which also correlate with the LOAC total aerosol volume time-series. An estimate of HCl/SO2 in Etna emissions was made by Multi-Gas electrochemical sensor, using a novel design to limit absorption/desorption effects and low-noise electronics for improved resolution. The detection of volcanic HCl by electrochemical sensor brings new possibilities for Multi-Gas monitoring of volcanic halogen emissions. Electrochemical sensor response times are not instantaneous, particularly for sticky gases such as HCl (T90 ~min), but also even for "fast" response (T90 ~ 10 to 30 s) sensors such as SO2 and H2S. However, in a volcanic

  8. Use of In Situ Cloud Condensation Nuclei, Extinction, and Aerosol Size Distribution Measurements to Test a Method for Retrieving Cloud Condensation Nuclei Profiles From Surface Measurements

    NASA Technical Reports Server (NTRS)

    Ghan, Stephen J.; Rissman, Tracey A.; Ellman, Robert; Ferrare, Richard A.; Turner, David; Flynn, Connor; Wang, Jian; Ogren, John; Hudson, James; Jonsson, Haflidi H.; VanReken, Timothy; Flagan, Richard C.; Seinfeld, John H.

    2006-01-01

    If the aerosol composition and size distribution below cloud are uniform, the vertical profile of cloud condensation nuclei (CCN) concentration can be retrieved entirely from surface measurements of CCN concentration and particle humidification function and surface-based retrievals of relative humidity and aerosol extinction or backscatter. This provides the potential for long-term measurements of CCN concentrations near cloud base. We have used a combination of aircraft, surface in situ, and surface remote sensing measurements to test various aspects of the retrieval scheme. Our analysis leads us to the following conclusions. The retrieval works better for supersaturations of 0.1% than for 1% because CCN concentrations at 0.1% are controlled by the same particles that control extinction and backscatter. If in situ measurements of extinction are used, the retrieval explains a majority of the CCN variance at high supersaturation for at least two and perhaps five of the eight flights examined. The retrieval of the vertical profile of the humidification factor is not the major limitation of the CCN retrieval scheme. Vertical structure in the aerosol size distribution and composition is the dominant source of error in the CCN retrieval, but this vertical structure is difficult to measure from remote sensing at visible wavelengths.

  9. Nonlinear optical studies of terpene-functionalized silica and its interactions with ozone as models for tropospheric aerosol chemistry

    NASA Astrophysics Data System (ADS)

    Stokes, G. Y.; Buchbinder, A. M.; Gibbs-Davis, J. M.; Scheidt, K. A.; Geiger, F. M.

    2008-12-01

    Terpenes emitted from vegetation can become oxidized and form molecular films on tropospheric aerosols. These greasy olefinic coatings can be oxidized by ozone and may influence the microphysics of cloud formation and the earth's climate. Using a laboratory approach that combines organic synthesis with nonlinear optical spectroscopy, we utilized vibrational broadband sum frequency generation (SFG) to survey a number of terpene-modified glass surfaces and track their interactions with ozone in real time. Exposure of these surfaces to tropospherically relevant amounts of ozone at 1 atm total pressure and 296 K yield initial reactive uptake coefficients that are significantly higher than those measured in corresponding gas phase reactions and correlate with the accessibility of the C=C double bonds at the surface. The intensity changes in the olefinic =C-H stretch and aliphatic C-H stretching region of surface vibrational spectra were used to characterize surface-bound product species. Combined with a histogram analysis of contact angle measurements carried out before and after ozonolysis, our kinetic and spectroscopic studies suggest a reaction pathway involving vibrationally hot Criegee intermediates that strongly compete with pathways that involve thermalized surface species, a chemical insight which may help reduce uncertainties associated with aerosols when included in global climate change models.

  10. Potential impact of combined NO[sub x] and SO[sub x] emissions from future high speed civil transport aircraft on stratospheric aerosols and ozone

    SciTech Connect

    Bekki, S.; Pyle, J.A.

    1993-02-01

    A two-dimensional sulfate aerosol model is used to assess the impact of combined NO[sub x] and SO[sub x] emissions from future High Speed Civil Transports on stratospheric aerosols and ozone. The model predicts that SO[sub x] emitted by this fleet of supersonics may double the aerosol surface area and the number of optically active particles below 20 km in the northern lower stratosphere. When the heterogeneous conversion of N[sub 2]O[sub 5] to HNO[sub 3] on sulfate aerosols is taken into account, the predicted ozone changes due to future HSCTs emissions are smaller than those calculated when SO[sub x] and the subsequent increase in aerosol loading are neglected. It is worth noting that the doubling of the aerosol surface area may lead not only to a reduction in predicted ozone sensitivity to NO[sub x], but also to an enhancement in ozone sensitivity to chlorine in the lower stratosphere. 23 refs., 3 figs.

  11. Analysis of Venus Express optical extinction due to aerosols in the upper haze of Venus

    NASA Astrophysics Data System (ADS)

    Parkinson, Christopher; Bougher, Stephen; Mahieux, Arnaud; Tellmann, Silvia; Pätzold, Martin; Vandaele, Ann C.; Wilquet, Valérie; Schulte, Rick; Yung, Yuk; Gao, Peter; Bardeen, Charles

    Observations by the SPICAV/SOIR instruments aboard Venus Express (VEx) have revealed that the Upper Haze of Venus is populated by two particle modes, as reported by Wilquet et al. (J. Geophys. Res., 114, E00B42, 2009; Icarus 217, 2012). Gao et al. (In press, Icarus, 2013) posit that the large mode is made up of cloud particles that have diffused upwards from the cloud deck below, while the smaller mode is generated by the in situ nucleation of meteoric dust. They tested this hypothesis by using version 3.0 of the Community Aerosol and Radiation Model for Atmospheres, first developed by Turco et al. (J. Atmos. Sci., 36, 699-717, 1979) and upgraded to version 3.0 by Bardeen et al. (The CARMA 3.0 microphysics package in CESM, Whole Atmosphere Working Group Meeting, 2011). Using the meteoric dust production profile of Kalashnikova et al. (Geophys. Res. Lett., 27, 3293-3296, 2000), the sulfur/sulfate condensation nuclei production profile of Imamura and Hashimoto (J. Atmos. Sci., 58, 3597-3612, 2001), and sulfuric acid vapor production profile of Zhang et al. (Icarus, 217, 714-739, 2012), they numerically simulate a column of the Venus atmosphere from 40 to 100 km above the surface. Their aerosol number density results agree well with Pioneer Venus Orbiter (PVO) data from Knollenberg and Hunten (J. Geophys. Res., 85, 8039-8058, 1980), while their gas distribution results match that of Kolodner and Steffes below 55 km (Icarus, 132, 151-169, 1998). The resulting size distribution of cloud particles shows two distinct modes, qualitatively matching the observations of PVO. They also observe a third mode in their results with a size of a few microns at 48 km altitude, which appears to support the existence of the controversial third mode in the PVO data. This mode disappears if coagulation is not included in the simulation. The Upper Haze size distribution shows two lognormal-like distributions overlapping each other, possibly indicating the presence of the two distinct

  12. Model Study of Ozone Levels Over Snow-Covered Surfaces

    NASA Astrophysics Data System (ADS)

    Sandoval, A. E.; Jacobson, M. Z.

    2001-12-01

    A column gas-aerosol-radiative model is used to simulate chemistry and radiation in and above snowpack at mid-latitudes and over the Arctic. Fifty vertical layers are modeled, the lowest of which represent the upper 15 cm of the snowpack. Snow layers are treated as dense aerosol layers with the physical and optical properties of snow. Aqueous phase and heterogeneous reactions thought to occur in the snowpack are represented as reactions on the aerosol surface. Model simulations include analysis of (1) the spectral UV radiation extinction in the snowpack, (2) chemistry over the snowpack, including snowpack release of NOx and H2O2 and ozone reduction and its susceptibility to the presence of aldehydes and bromine, (3) and the effect of soot in snow on chemistry, UV extinction, and local energy balance. Model predictions are compared to measurements of UV fluxes and ozone over snow.

  13. Measurements of Biogenic and Anthropogenic Ozone and Aerosol Precursors during the SENEX (Southeast Nexus) Campaign 2013

    NASA Astrophysics Data System (ADS)

    Warneke, C.; Trainer, M.; De Gouw, J. A.

    2013-12-01

    Natural emissions of ozone and aerosol precursor gases such as isoprene and monoterpenes are the highest in the southeast of the U.S. and rival those found in tropical forests. In addition, anthropogenic emissions are significant in the Southeast and photochemistry is rapid. The southeast U.S. has not warmed like other parts of the U.S. in response to global climate change, and the temperature anomaly has been suggested to be related to aerosols derived from a combination of anthropogenic and biogenic precursors. The NOAA SENEX aircraft campaign took place in June-July 2013 in the southeast U.S. as part of the Southeast Atmosphere Study (SAS). The NOAA WP-3 aircraft conducted 20 research flights between May 27 and July 10, 2013 based out of Smyrna, TN. To investigate the combination of anthropogenic and biogenic emissions several flights were designed to follow the emissions of cities and power plants as they are transported over forested regions in the Southeast. For example, over-flights of Atlanta, Birmingham and Nashville were performed and the plumes were followed to the forested areas with high isoprene and monoterpene emissions. The same was done for several power plants such as EC Gaston, Scherer and Johnsonville. In the anthropogenic plumes, effects such as the modulation of the isoprene chemistry by high NOx and particle formation and growth were investigated. The same strategy was used for three nighttime flights over Atlanta, Birmingham and the New Madrid and White Bluff power plants. Flights over and downwind of St Lois and Indianapolis were used as a contrast in areas with smaller biogenic emissions. Other anthropogenic emissions sources that were investigated during SENEX included bio refineries, paper mills, coalmines, poultry and pork farming. Also biomass burning emissions were observed during one daytime and one nighttime flight. Another focus of the SENEX campaign was to determine the emissions of natural gas and oil production from the

  14. SAGE aerosol measurements. Volume 3: January 1, 1981 to November 18, 1981

    NASA Technical Reports Server (NTRS)

    Mccormick, M. Patrick

    1987-01-01

    The Stratospheric Aerosol and Gas Experiment (SAGE) satellite system, launched February 18, 1979, obtained profiles of aerosol extinction at 1.00 micron and 0.45 micron ozone concentration, and nitrogen dioxide concentration. Data taken during sunset events are presented in the form of zonal and seasonal averages of aerosol extinction of 1.00 micron and 0.45 micron, ratios of aerosol extinction to molecular extinction at 1.00 micron and ratios of aerosol extinction at 0.45 micron to aerosol extinction at 1.00 micron. Averages for 1981 are shown in tables, and in profile and contour plots (as a function of altitude and latitude). In addition, temperature data provided by NOAA for the time and location of each SAGE measurement are averaged and shown in a similar format. The stratospheric aerosol distribution for 1981 shows effects of volcanically injected material from eruptions of Ulawun, Alaid, and Pagan. Peak values of aerosol extinction at 0.45 micron and 1.00 micron were 2 to 4 times higher than typical peak values observed during near background conditions. Stratospheric aerosol optical depth values at 1.00 microns increased by a factor of about 2 from near background levels in regions of volcanic activity. During the year, these values ranged from between 0.001 and 0.006. The largest were near the location of a recent eruption. The distribution of the ratio of aerosol to molecular extinction at 1.00 microns also showed that maximum values are found in the vicinity of an eruption. These maximums varied in altitude, but remained below a height of about 25 km. No attempt has been made to give detailed explanations or interpretations of these data. The intent is to provide, in a ready-to-use visual format, representative zonal and seasonal averages of aerosol extinction data for the third calendar year of the SAGE data set to facilitate atmospheric and climatic studies.

  15. SAGE aerosol measurements. Volume 3: January 1, 1981 to November 18, 1981

    NASA Astrophysics Data System (ADS)

    McCormick, M. Patrick

    1987-02-01

    The Stratospheric Aerosol and Gas Experiment (SAGE) satellite system, launched February 18, 1979, obtained profiles of aerosol extinction at 1.00 micron and 0.45 micron ozone concentration, and nitrogen dioxide concentration. Data taken during sunset events are presented in the form of zonal and seasonal averages of aerosol extinction of 1.00 micron and 0.45 micron, ratios of aerosol extinction to molecular extinction at 1.00 micron and ratios of aerosol extinction at 0.45 micron to aerosol extinction at 1.00 micron. Averages for 1981 are shown in tables, and in profile and contour plots (as a function of altitude and latitude). In addition, temperature data provided by NOAA for the time and location of each SAGE measurement are averaged and shown in a similar format. The stratospheric aerosol distribution for 1981 shows effects of volcanically injected material from eruptions of Ulawun, Alaid, and Pagan. Peak values of aerosol extinction at 0.45 micron and 1.00 micron were 2 to 4 times higher than typical peak values observed during near background conditions. Stratospheric aerosol optical depth values at 1.00 microns increased by a factor of about 2 from near background levels in regions of volcanic activity. During the year, these values ranged from between 0.001 and 0.006. The largest were near the location of a recent eruption. The distribution of the ratio of aerosol to molecular extinction at 1.00 microns also showed that maximum values are found in the vicinity of an eruption. These maximums varied in altitude, but remained below a height of about 25 km. No attempt has been made to give detailed explanations or interpretations of these data. The intent is to provide, in a ready-to-use visual format, representative zonal and seasonal averages of aerosol extinction data for the third calendar year of the SAGE data set to facilitate atmospheric and climatic studies.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  17. Evaluation of the impact of atmospheric ozone and aerosols on the horizontal global/diffuse UV Index at Livorno (Italy)

    NASA Astrophysics Data System (ADS)

    Scaglione, Daniele; Giulietti, Danilo; Morelli, Marco

    2016-08-01

    A study was conducted at Livorno (Italy) to evaluate the impact of atmospheric aerosols and ozone on the solar UV radiation and its diffuse component at ground in clear sky conditions. Solar UV radiation has been quantified in terms of UV Index (UVI), following the ISO 17166:1999/CIE S007/E-1998 international standard. UVI has been calculated by exploiting the libRadtran radiative transfer modelling software as a function of both the Aerosols Optical Depth (AOD) and the Total Ozone Column (TOC). In particular AOD and TOC values have been remotely sensed by the Ozone Monitoring Instrument (OMI) on board the NASA's EOS (Earth Observing System) satellites constellation. An experimental confirmation was also obtained by exploiting global UVI ground-based measurements from the 26/9/14 to 12/8/15 and diffuse UVI ground-based measurements from the 17/5/15 to 12/8/15. For every considered value of Solar Zenith Angle (SZA) and atmospheric condition, estimates and measurements confirm that the diffuse component contributes for more than 50% on the global UV radiation. Therefore an exposure of human skin also to diffuse solar UV radiation can be potentially harmful for health and need to be accurately monitored, e.g. by exploiting innovative applications such as a mobile app with a satellite-based UV dosimeter that has been developed. Global and diffuse UVI variations due to the atmosphere are primarily caused by the TOC variations (typically cyclic): the maximum TOC variation detected by OMI in the area under study leads to a corresponding variation in global and diffuse UVI of about 50%. Aerosols in the area concerned, mainly of maritime nature, have instead weaker effects causing a maximum variation of the global and diffuse UVI respectively of 9% and 35% with an SZA of 20° and respectively of 13% and 10% with an SZA of 60°.

  18. Study Of The Effects Of Aerosol And Ozone On The Ultraviolet Radiation In The Mediterranean By Means Of Measurements And Radiation Transfer Model

    NASA Astrophysics Data System (ADS)

    Meloni, D.; di Sarra, A.; Cacciani, M.; di Iorio, T.; Fiocco, G.; Junkermann, W.; Deluisi, J.

    During the Photochemical Activity and Solar Ultraviolet Radiation modulation fac- tors II (PAUR II) campaign an articulated set of measurements of ultraviolet radia- tion, aerosol properties, and atmospheric chemical composition was collected in the Mediterranean. Measurements of UV and visible irradiance, ozone and aerosol were performed also at the island of Lampedusa (35.5 N, 12.6 E) in May-June 1999. Sev- eral Saharan dust events occurred during the PAUR II campaign, and large aerosol amounts were detected over Lampedusa in different occasions. A radiative transfer model has been used to investigate the role of ozone and aerosols in modulating UV irradiance and to reproduce the UV spectra measured by the Brewer spectrophotometer in cloud-free conditions. The model is initialized with a large set of observations, allowing a detailed characterization of the atmospheric properties. Particular efforts have been devoted to reconstruct the aerosol distribution and optical properties. The combined used of the measured spectra and of the radiation transfer model allows an estimate of the aerosol refractive index, of the UV radiative forcing due to aerosol, and of the effects of different vertical distributions of ozone.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  20. Analysis of Venus Express optical extinction due to aerosols in the upper haze of Venus

    NASA Astrophysics Data System (ADS)

    Parkinson, C. D.; Bougher, S. W.; Schulte, R.; Gao, P.; Yung, Y. L.; Vandaele, A.; Wilquet, V.; Mahieux, A.; Tellmann, S.

    2013-12-01

    Observations by the SPICAV/SOIR instruments aboard the Venus Express (VEx) spacecraft have revealed that the upper haze (UH) of Venus, between 70 and 90 km, is variable on the order of days to weeks and that it is populated by two particle modes. Gao et al. (submitted, Icarus, 2013) posit that one mode is made up of cloud particles that have diffused upwards from the main sulfuric acid cloud deck below, while the other mode is generated in situ by nucleation of sulfuric acid droplets on meteoric dust. They also propose that the observed variability in the UH is caused in part by vertical transient winds. They test this hypothesis by simulating a column of the Venus atmosphere from 40 to 100 km above the surface using a model based upon the Community Aerosol and Radiation Model for Atmospheres (CARMA). In this work, we significantly extend the analysis using the new more detailed SOIR/VeRa VEx temperature profiles which better constrain the observed strong CO2 15-micron cooling emission and 4.3-μm near-IR heating in Venus' atmosphere (and consistent with Venus Thermospheric General Circulation Model (VTGCM) simulations of Brecht et al. (2011)). We discuss our new results in context of the recent VEx observations (Wilquet et al., Icarus 217, 2012) with an intercomparison with the PVO data. We will also discuss similarities and differences arising from the PVO and VEx epochs where they exist. Additionally we report on our efforts self-consistently applying the VTGCM to constrain the degree to which effects due to vertical transient wind simulations can establish variability timescales and number density profiles that match VEx observations.

  1. Information Retrieval from SAGE II and MFRSR Multi-Spectral Extinction Measurements

    NASA Technical Reports Server (NTRS)

    Lacis, Andrew A.; Hansen, James E. (Technical Monitor)

    2001-01-01

    Direct beam spectral extinction measurements of solar radiation contain important information on atmospheric composition in a form that is essentially free from multiple scattering contributions that otherwise tend to complicate the data analysis and information retrieval. Such direct beam extinction measurements are available from the solar occultation satellite-based measurements made by the Stratospheric and Aerosol Gas Experiment (SAGE II) instrument and by ground-based Multi-Filter Shadowband Radiometers (MFRSRs). The SAGE II data provide cross-sectional slices of the atmosphere twice per orbit at seven wavelengths between 385 and 1020 nm with approximately 1 km vertical resolution, while the MFRSR data provide atmospheric column measurements at six wavelengths between 415 and 940 nm but at one minute time intervals. We apply the same retrieval technique of simultaneous least-squares fit to the observed spectral extinctions to retrieve aerosol optical depth, effective radius and variance, and ozone, nitrogen dioxide, and water vapor amounts from the SAGE II and MFRSR measurements. The retrieval technique utilizes a physical model approach based on laboratory measurements of ozone and nitrogen dioxide extinction, line-by-line and numerical k-distribution calculations for water vapor absorption, and Mie scattering constraints on aerosol spectral extinction properties. The SAGE II measurements have the advantage of being self-calibrating in that deep space provides an effective zero point for the relative spectral extinctions. The MFRSR measurements require periodic clear-day Langley regression calibration events to maintain accurate knowledge of instrument calibration.

  2. Measuring the characteristics of stratospheric aerosol layer and total ozone concentration at Siberian Lidar Station in Tomsk

    NASA Astrophysics Data System (ADS)

    Nevzorov, Aleksey; Bazhenov, Oleg; Burlakov, Vladimir; Dolgii, Sergey

    2015-11-01

    We consider the results of long-term remote optical monitoring, obtained at the Siberian Lidar Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences in Tomsk (56.5 °N, 85.0 °E). The scattering characteristics of stratospheric aerosol layer, obtained according to data of lidar measurements since 1986, are presented. We analyze the trends of changes in the total ozone (TO) content over Tomsk for the period 1996-2013 according to data of spectrophotometric measurements with employment of TOMS satellite data for the period 1979- 1994. We determined the periods of elevated content of stratospheric aerosol over Tomsk after a series of explosive eruptions of volcanoes of Pacific Ring of Fire and Iceland in 2006-2011. Since the second half of 1990s, researchers record an increasing TO trend, equaling 0.65 DU/yr for the period 1996-2013.

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

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.

    1985-01-01

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

  4. Total ozone column, water vapour and aerosol effects on erythemal and global solar irradiance in Marsaxlokk, Malta

    NASA Astrophysics Data System (ADS)

    Bilbao, Julia; Román, Roberto; Yousif, Charles; Mateos, David; de Miguel, Argimiro

    2014-12-01

    Observations of erythemal (UVER; 280-400 nm) and total solar shortwave irradiance (SW; 305-2800 nm), total ozone column (TOC), water vapour column (w), aerosol optical depth (AOD) and Ångström exponent (α) were carried out at Marsaxlokk, in south-east Malta. These measurements were recorded during a measurement campaign between May and October 2012, aimed at studying the influence of atmospheric compounds on solar radiation transfer through the atmosphere. The effects of TOC, AOD and w on UVER and SW (global, diffuse and direct) irradiance were quantified using irradiance values under cloud-free conditions at different fixed solar zenith angles (SZA). Results show that UVER (but not SW) irradiance correlates well with TOC. UVER variations ranged between -0.24% DU-1 and -0.32% DU-1 with all changes being statistically significant. Global SW irradiance varies with water vapour column between -2.44% cm-1 and -4.53% cm-1, these results proving statistically significant and diminishing when SZA increases. The irradiance variations range between 42.15% cm-1 and 20.30% cm-1 for diffuse SW when SZA varies between 20° and 70°. The effect of aerosols on global UVER is stronger than on global SW. Aerosols cause a UVER reduction of between 28.12% and 52.41% and a global SW reduction between 13.46% and 41.41% per AOD550 unit. Empirical results show that solar position plays a determinant role, that there is a negligible effect of ozone on SW radiation, and stronger attenuation by aerosol particles in UVER radiation.

  5. Radiative Forcing Due to Enhancements in Tropospheric Ozone and Carbonaceous Aerosols Caused by Asian Fires During Spring 2008

    NASA Technical Reports Server (NTRS)

    Natarajan, Murali; Pierce, R. Bradley; Lenzen, Allen J.; Al-Saadi, Jassim A.; Soja, Amber J.; Charlock, Thomas P.; Rose, Fred G.; Winker, David M.; Worden, John R.

    2012-01-01

    Simulations of tropospheric ozone and carbonaceous aerosol distributions, conducted with the Real-time Air Quality Modeling System (RAQMS), are used to study the effects of major outbreaks of fires that occurred in three regions of Asia, namely Thailand, Kazakhstan, and Siberia, during spring 2008. RAQMS is a global scale meteorological and chemical modeling system. Results from these simulations, averaged over April 2008, indicate that tropospheric ozone column increases by more than 10 Dobson units (DU) near the Thailand region, and by lesser amounts in the other regions due to the fires. Widespread increases in the optical depths of organic and black carbon aerosols are also noted. We have used an off-line radiative transfer model to evaluate the direct radiative forcing due to the fire-induced changes in atmospheric composition. For clear sky, the monthly averaged radiative forcing at the top of the atmosphere (TOA) is mostly negative with peak values less than -12 W/sq m occurring near the fire regions. The negative forcing represents the increased outgoing shortwave radiation caused by scattering due to carbonaceous aerosols. At high latitudes, the radiative forcing is positive due to the presence of absorbing aerosols over regions of high surface albedo. Regions of positive forcing at TOA are more pronounced under total sky conditions. The monthly averaged radiative forcing at the surface is mostly negative, and peak values of less than -30 W/sq m occur near the fire regions. Persistently large negative forcing at the surface could alter the surface energy budget and potentially weaken the hydrological cycle.

  6. Radiative forcing due to enhancements in tropospheric ozone and carbonaceous aerosols caused by Asian fires during spring 2008

    NASA Astrophysics Data System (ADS)

    Natarajan, Murali; Pierce, R. Bradley; Schaack, Todd K.; Lenzen, Allen J.; Al-Saadi, Jassim A.; Soja, Amber J.; Charlock, Thomas P.; Rose, Fred G.; Winker, David M.; Worden, John R.

    2012-03-01

    Simulations of tropospheric ozone and carbonaceous aerosol distributions, conducted with the Real-time Air Quality Modeling System (RAQMS), are used to study the effects of major outbreaks of fires that occurred in three regions of Asia, namely Thailand, Kazakhstan, and Siberia, during spring 2008. RAQMS is a global scale meteorological and chemical modeling system. Results from these simulations, averaged over April 2008, indicate that tropospheric ozone column increases by more than 10 Dobson units (DU) near the Thailand region, and by lesser amounts in the other regions due to the fires. Widespread increases in the optical depths of organic and black carbon aerosols are also noted. We have used an off-line radiative transfer model to evaluate the direct radiative forcing due to the fire-induced changes in atmospheric composition. For clear sky, the monthly averaged radiative forcing at the top of the atmosphere (TOA) is mostly negative with peak values less than -12 W/m2 occurring near the fire regions. The negative forcing represents the increased outgoing shortwave radiation caused by scattering due to carbonaceous aerosols. At high latitudes, the radiative forcing is positive due to the presence of absorbing aerosols over regions of high surface albedo. Regions of positive forcing at TOA are more pronounced under total sky conditions. The monthly averaged radiative forcing at the surface is mostly negative, and peak values of less than -30 W/m2 occur near the fire regions. Persistently large negative forcing at the surface could alter the surface energy budget and potentially weaken the hydrological cycle.

  7. SAGE 2-Umkehr case study of ozone differences and aerosol effects from October 1984 to April 1989

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

    A comparison of 1262 cases of coincident ozone profiles derived from 666 Umkehrs at 17 different stations and 901 SAGE 2 profiles within 1000 km and 12 hours between October 1984 and April 1989 indicates the following layer percentage differences with 2-sigma error bars: layer three 14.6 plus/minus 3.3 percent, layer four 17.6 plus/minus 1.1 percent, layer five -1.3 plus/minus 0.5 percent, layer six -5.7 plus/minus 0.7 percent, layer seven -1.0 plus/minus 0.7 percent, layer eight 4.2 plus/minus 0.7 percent, and layer nine 6.8 plus/minus 1.2 percent. Comparing SAGE 2-Umkehr differences to SAGE 1 version 5.5-Umkehr differences shows SAGE 2 higher than or equal to SAGE 1 relative to Umkehr in all layers except layer three. Adjustment for this bias would produce trends derived from SAGE 2-SAGE 1 differences and Umkehr observations in the 1980s more nearly equal to each other in layers six, seven, and eight. A possible explanation of these differences is a systematic shift in the reference altitude between SAGE 1 and SAGE 2, but there is no independent evidence of this. While the shape of the vertical profile of differences at 17 individual Umkehr stations (mostly in mid-latitudes) is generally consistent at all stations except at Poker Flat, Seoul, and Lauder, significant variation does exists among the stations. The profile of mean difference is similar to previously observed differences between Umkehr and both SAGE 2 and SBUV and also to an eigenvector analysis, but with site-dependent amplitude discrepancies. Because of the close correspondence of stratospheric aerosol optical depth at the SAGE 2-measured 0.525 micron wavelength and the extrapolated 0.32 Umkehr wavelength determined in this study, we use the 0.525 micron data to determine the aerosol effect of Umkehr profiles. The aerosol errors to the Umkehr ozone amounts in percent ozone amount per 0.01 stratospheric aerosol optical depth range from plus 2 percent in layer six to minus 3 percent in layer nine

  8. Transmission of 10 micron radiation over coastal waters: comparison of point-source image intensities with aerosol extinction and MODTRAN calculations

    NASA Astrophysics Data System (ADS)

    Schwering, Piet B.; de Leeuw, Gerrit; van Eijk, Alexander M.

    1996-10-01

    During the MAPTIP experiments in the Dutch coastal waters, 11 October - 5 November 1993, transmission curves were determined from the intensities of the image of a point source suspended from a helicopter at ranges between 0.5 and 6 NMi. The images were recorded with a 10 micrometer USFA 9092 camera from the MeetPost Noordwijk, a research tower in the North Sea at 9 km from the Dutch coast. The transmission determined from the point source intensities at several ranges is compared with calculated values. The transmission is determined by extinction due to aerosols and molecular species in the propagation path. Both contributions can be determined using code using measured size distributions. Also effects of path radiance and background on the image intensity are considered. In this coastal area, and the off- shore winds that were usually encountered during MAPTIP, the aerosol size distributions are known to be a complicated mixture of continental and marine aerosols. Hence the common aerosol models, that usually work well over the open ocean, are often not so reliable in a coastal environment. An attempt is made to assess the influence of marine and anthropogenic contributions to the aerosol on the detection range of point targets in a coastal atmosphere.

  9. Error analysis of Raman differential absorption lidar ozone measurements in ice clouds.

    PubMed

    Reichardt, J

    2000-11-20

    A formalism for the error treatment of lidar ozone measurements with the Raman differential absorption lidar technique is presented. In the presence of clouds wavelength-dependent multiple scattering and cloud-particle extinction are the main sources of systematic errors in ozone measurements and necessitate a correction of the measured ozone profiles. Model calculations are performed to describe the influence of cirrus and polar stratospheric clouds on the ozone. It is found that it is sufficient to account for cloud-particle scattering and Rayleigh scattering in and above the cloud; boundary-layer aerosols and the atmospheric column below the cloud can be neglected for the ozone correction. Furthermore, if the extinction coefficient of the cloud is ?0.1 km(-1), the effect in the cloud is proportional to the effective particle extinction and to a particle correction function determined in the limit of negligible molecular scattering. The particle correction function depends on the scattering behavior of the cloud particles, the cloud geometric structure, and the lidar system parameters. Because of the differential extinction of light that has undergone one or more small-angle scattering processes within the cloud, the cloud effect on ozone extends to altitudes above the cloud. The various influencing parameters imply that the particle-related ozone correction has to be calculated for each individual measurement. Examples of ozone measurements in cirrus clouds are discussed. PMID:18354611

  10. Ozone

    SciTech Connect

    Not Available

    1988-06-01

    The author discusses the debate over whether concern about a hole in the ozone layer in Antarctic is real or science fiction. There is a growing consensus that efforts must be taken to protect the ozone layer. The issue now is not whether chlorofluorocarbons (CFCs) should be controlled and regulated but how much and how soon. The United States has urged that the production of dangerous CFCs, and any other chemicals that affect the ozone layer, be restricted immediately to current levels and that their use be reduced 95 percent over the next decade. The American position was too strong for many European nations and the Japanese. Negotiations at an international conference on the matter broke down. The breakdown is due in part to a more acute concern for environmental matters in the United States than exists in many countries. Meanwhile CFCs are linked to another environmental problem that equally threatens the world - the Greenhouse Effect. The earth is in a natural warming period, but man could be causing it to become even warmer. The Greenhouse Effect could have a catastrophic impact on mankind, although nothing has been proven yet.

  11. A Chronology of Annual-Mean Effective Radii of Stratospheric Aerosols from Volcanic Eruptions During the Twentieth Century as Derived From Ground-based Spectral Extinction Measurements

    NASA Technical Reports Server (NTRS)

    Strothers, Richard B.; Hansen, James E. (Technical Monitor)

    2001-01-01

    Stratospheric extinction can be derived from ground-based spectral photometric observations of the Sun and other stars (as well as from satellite and aircraft measurements, available since 1979), and is found to increase after large volcanic eruptions. This increased extinction shows a characteristic wavelength dependence that gives information about the chemical composition and the effective (or area weighted mean) radius of the particles responsible for it. Known to be tiny aerosols constituted of sulfuric acid in a water solution, the stratospheric particles at midlatitudes exhibit a remarkable uniformity of their column-averaged effective radii r(sub eff) in the first few months after the eruption. Considering the seven largest eruptions of the twentieth century, r(sub eff) at this phase of peak aerosol abundance is approx. 0.3 micrometers in all cases. A year later, r(sub eff) either has remained about the same size (almost certainly in the case of the Katmai eruption of 1912) or has increased to approx. 0.5 micrometers (definitely so for the Pinatubo eruption of 1991). The reasons for this divergence in aerosol growth are unknown.

  12. Aircraft Measurements of BrO, IO, Glyoxal, NO2, H2O, O2-O2 and Aerosol Extinction Profiles in the Tropics: Comparison with Aircraft-/Ship-Based in Situ and Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Volkamer, R.; Baidar, S.; Campos, T. L.; Coburn, S.; DiGangi, J. P.; Dix, B.; Eloranta, E. W.; Koenig, T. K.; Morley, B.; Ortega, I.; Pierce, B. R.; Reeves, M.; Sinreich, R.; Wang, S.; Zondlo, M. A.; Romashkin, P. A.

    2015-01-01

    Tropospheric chemistry of halogens and organic carbon over tropical oceans modifies ozone and atmospheric aerosols, yet atmospheric models remain largely untested for lack of vertically resolved measurements of bromine monoxide (BrO), iodine monoxide (IO) and small oxygenated hydrocarbons like glyoxal (CHOCHO) in the tropical troposphere. BrO, IO, glyoxal, nitrogen dioxide (NO2), water vapor (H2O) and O2-O2 collision complexes (O4/ were measured by the University of Colorado Airborne Multi-AXis Differential Optical Absorption Spectroscopy (CU AMAXDOAS) instrument, aerosol extinction by high spectral resolution lidar (HSRL), in situ aerosol size distributions by an ultra high sensitivity aerosol spectrometer (UHSAS) and in situ H2O by vertical-cavity surface-emitting laser (VCSEL) hygrometer. Data are presented from two research flights (RF12, RF17) aboard the National Science Foundation/ National Center for Atmospheric Research Gulfstream V aircraft over the tropical Eastern Pacific Ocean (tEPO) as part of the "Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated hydrocarbons" (TORERO) project (January/February 2012). We assess the accuracy of O4 slant column density (SCD) measurements in the presence and absence of aerosols. Our O4-inferred aerosol extinction profiles at 477 nm agree within 6% with HSRL in the boundary layer and closely resemble the renormalized profile shape of Mie calculations constrained by UHSAS at low (sub-Rayleigh) aerosol extinction in the free troposphere. CU AMAX-DOAS provides a flexible choice of geometry, which we exploit to minimize the SCD in the reference spectrum (SCDREF, maximize signal-to-noise ratio) and to test the robustness of BrO, IO and glyoxal differential SCDs. The RF12 case study was conducted in pristine marine and free tropospheric air. The RF17 case study was conducted above the NOAA RV Ka'imimoana (TORERO cruise, KA-12-01) and provides independent validation data from ship-based in situ cavity

  13. Aircraft measurements of BrO, IO, glyoxal, NO2, H2O, O2-O2 and aerosol extinction profiles in the tropics: comparison with aircraft-/ship-based in situ and lidar measurements

    NASA Astrophysics Data System (ADS)

    Volkamer, R.; Baidar, S.; Campos, T. L.; Coburn, S.; DiGangi, J. P.; Dix, B.; Eloranta, E. W.; Koenig, T. K.; Morley, B.; Ortega, I.; Pierce, B. R.; Reeves, M.; Sinreich, R.; Wang, S.; Zondlo, M. A.; Romashkin, P. A.

    2015-05-01

    Tropospheric chemistry of halogens and organic carbon over tropical oceans modifies ozone and atmospheric aerosols, yet atmospheric models remain largely untested for lack of vertically resolved measurements of bromine monoxide (BrO), iodine monoxide (IO) and small oxygenated hydrocarbons like glyoxal (CHOCHO) in the tropical troposphere. BrO, IO, glyoxal, nitrogen dioxide (NO2), water vapor (H2O) and O2-O2 collision complexes (O4) were measured by the University of Colorado Airborne Multi-AXis Differential Optical Absorption Spectroscopy (CU AMAX-DOAS) instrument, aerosol extinction by high spectral resolution lidar (HSRL), in situ aerosol size distributions by an ultra high sensitivity aerosol spectrometer (UHSAS) and in situ H2O by vertical-cavity surface-emitting laser (VCSEL) hygrometer. Data are presented from two research flights (RF12, RF17) aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V aircraft over the tropical Eastern Pacific Ocean (tEPO) as part of the "Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated hydrocarbons" (TORERO) project (January/February 2012). We assess the accuracy of O4 slant column density (SCD) measurements in the presence and absence of aerosols. Our O4-inferred aerosol extinction profiles at 477 nm agree within 6% with HSRL in the boundary layer and closely resemble the renormalized profile shape of Mie calculations constrained by UHSAS at low (sub-Rayleigh) aerosol extinction in the free troposphere. CU AMAX-DOAS provides a flexible choice of geometry, which we exploit to minimize the SCD in the reference spectrum (SCDREF, maximize signal-to-noise ratio) and to test the robustness of BrO, IO and glyoxal differential SCDs. The RF12 case study was conducted in pristine marine and free tropospheric air. The RF17 case study was conducted above the NOAA RV Ka'imimoana (TORERO cruise, KA-12-01) and provides independent validation data from ship-based in situ cavity

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

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Butler, Carolyn F.; Kooi, Susan A.

    1991-01-01

    Consideration is given to O3 and aerosol distributions measured from an aircraft using a DIAL system in order to study the sources and sinks of gases and aerosols over the tundra regions of Alaska during summer 1988. The tropospheric O3 budget over the Arctic was found to be strongly influenced by stratospheric intrusions. Regions of low aerosol scattering and enhanced O3 mixing ratios were usually correlated with descending air from the upper troposphere or lower stratosphere.

  15. Developing a model system for studying the ozone processing of atmospheric aerosols by following changes in surface properties

    NASA Astrophysics Data System (ADS)

    Gonzalez-Labrada, Erick

    Atmospheric aerosols have a significant organic composition as determined by field measurement studies. This organic material is released to the atmosphere from both natural and anthropogenic sources, such as wind bursting of the ocean surface, car exhausts, and meat cooking, among others. An inverted micelle model has been proposed in order to explain the high concentration of organic compounds in aerosol particles. The model describes an organic film coating the air-liquid interface of an aqueous aerosol core. Chemical processing of this organic film by atmospheric oxidants (such as OH radicals, O3, and NO3) through heterogeneous and multiphase reactions can activate the aerosol to participate in atmospheric chemistry. After reaction, the particle has an increased role in the absorption and scattering of incoming solar radiation and cloud formation. Another consequence of this oxidation is the decrease of the atmospheric budget of gas-phase trace species, as well as the formation of volatile products. Several studies have proposed that the ozonolysis of organic films in aerosols takes place mainly at the surface. Therefore, the objective of this research was to develop a suitable model system for following the reaction through quantitative changes of a property inherent to the surface. Several attempts were made to examine the ozonolysis of organic monolayers at either solid or liquid surfaces. The studied monolayers contained unsaturated organic compounds as the only component or as part of a binary mixture with saturated compounds. The study of the ozone processing of monolayers deposited on solid substrates revealed information about changes in the hydrophobic character of the surface that occurred because of the reaction. On the other hand, the processing of a monolayer spread on a pendant drop allowed a real-time monitoring of surface pressure changes. This permitted a kinetic study of the reaction that yielded parameters related exclusively to processes

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

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

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

  17. Lidar Ratios for Dust Aerosols Derived From Retrievals of CALIPSO Visible Extinction Profiles Constrained by Optical Depths from MODIS-Aqua and CALIPSO/CloudSat Ocean Surface Reflectance Measurements

    NASA Technical Reports Server (NTRS)

    Young, Stuart A.; Josset, Damien B.; Vaughan, Mark A.

    2010-01-01

    CALIPSO's (Cloud Aerosol Lidar Infrared Pathfinder Satellite Observations) analysis algorithms generally require the use of tabulated values of the lidar ratio in order to retrieve aerosol extinction and optical depth from measured profiles of attenuated backscatter. However, for any given time or location, the lidar ratio for a given aerosol type can differ from the tabulated value. To gain some insight as to the extent of the variability, we here calculate the lidar ratio for dust aerosols using aerosol optical depth constraints from two sources. Daytime measurements are constrained using Level 2, Collection 5, 550-nm aerosol optical depth measurements made over the ocean by the MODIS (Moderate Resolution Imaging Spectroradiometer) on board the Aqua satellite, which flies in formation with CALIPSO. We also retrieve lidar ratios from night-time profiles constrained by aerosol column optical depths obtained by analysis of CALIPSO and CloudSat backscatter signals from the ocean surface.

  18. Does absorption of ultraviolet B by stratospheric ozone and urban aerosols influence colon and breast cancer mortality rates? Contributions from NASA and NOAA data

    NASA Astrophysics Data System (ADS)

    Gorham, Edward D.; Garland, Frank C.; Mohr, Sharif B.; Grant, William B.; Garland, Cedric F.

    2005-08-01

    Although most ultraviolet B (UVB) radiation is absorbed by stratospheric ozone, dense anthropogenic sulfate aerosols in the troposphere may further attenuate UVB in some regions. Mortality rates from colon and breast cancer tend to be much higher in areas with low levels of UVB radiation. These high rates may be due in part to inadequate cutaneous photosynthesis of vitamin D. Satellite data on atmospheric aerosols, stratospheric ozone, and cloud cover were obtained from the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA). These data were combined with age-adjusted mortality rates from 175 countries reporting to the World Health Organization. Regression was used to assess the relationship of stratospheric ozone thickness, aerosol optical depth, cloud cover, solar UVB irradiance at the top of the atmosphere, average skin exposure, and a dietary factor with colon and breast cancer mortality rates. Solar UVB irradiance at the top of the atmosphere, total cloud cover, and atmospheric aerosols had the strongest associations with mortality rates, apart from a strong influence of diet. Since 95% of circulating vitamin D is derived from current or stored products of photosynthesis, which may be nonexistent or minimal much of the year above 37°N or below 37°S, attenuation of UVB by atmospheric aerosols and clouds may have a greater than expected adverse effect on human health.

  19. Characterization of a Photoacoustic Aerosol Absorption Spectrometer for Aircraft-based Measurements

    NASA Astrophysics Data System (ADS)

    Mason, B. J.; Wagner, N. L.; Richardson, M.; Brock, C. A.; Murphy, D. M.; Adler, G.

    2015-12-01

    Atmospheric aerosol directly impacts the Earth's climate through extinction of incoming and outgoing radiation. The optical extinction is due to both scattering and absorption. In situ measurements of aerosol extinction and scattering are well established and have uncertainties less than 5%. However measurements of aerosol absorption typically have uncertainties of 20-30%. Development and characterization of more accurate and precise instrumentation for measurement of aerosol absorption will enable a deeper understand of significance and spatial distribution of black and brown carbon aerosol, the effect of atmospheric processes on aerosol optical properties, and influence of aerosol optical properties on direct radiative forcing. Here, we present a detailed characterization of a photoacoustic aerosol absorption spectrometer designed for deployment aboard research aircraft. The spectrometer operates at three colors across the visible spectrum and is calibrated in the field using ozone. The field calibration is validated in the laboratory using synthetic aerosol and simultaneous measurements of extinction and scattering. In addition, the sensitivity of the instrument is characterized under conditions typically encountered during aircraft sampling e.g. as a function of changing pressure. We will apply this instrument characterization to ambient aerosol absorption data collected during the SENEX and SEAC4RS aircraft based field campaigns.

  20. Fluorescence spectra and biological activity of aerosolized bacillus spores and MS2 bacteriophage exposed to ozone at different relative humidities in a rotating drum

    SciTech Connect

    Ratnesar-Shumate, Shanna; Pan, Yong-Le; Hill, Steven C.; Kinahan, Sean; Corson, Elizabeth; Eshbaugh, Jonathan; Santarpia, Joshua L.

    2015-10-14

    Biological aerosols (bioaerosols) released into the environment may undergo physical and chemical transformations when exposed to atmospheric constituents such as solar irradiation, reactive oxygenated species, ozone, free radicals, water vapor and pollutants. Aging experiments were performed in a rotating drum chamber subjecting bioaerosols, Bacillus thuringiensis Al Hakam (BtAH) spores and MS2 bacteriophages to ozone at 0 and 150 ppb, and relative humidities (RH) at 10%, 50%, and 80+%. Fluorescence spectra and intensities of the aerosols as a function of time in the reaction chamber were measured with a single particle fluorescence spectrometer (SPFS) and an Ultra-Violet Aerodynamic Particle Sizer® Spectrometer (UV-APS). Losses in biological activity were measured by culture and quantitative polymerase chain reaction (q-PCR) assay. For both types of aerosols the largest change in fluorescence emission was between 280 and 400 nm when excited at 263 nm followed by fluorescence emission between 380 and 700 nm when excited at 351 nm. The fluorescence for both BtAH and MS2 were observed to decrease significantly at high ozone concentration and high RH when excited at 263 nm excitation. The decreases in 263 nm excited fluorescence are indicative of hydrolysis and oxidation of tryptophan in the aerosols. Fluorescence measured with the UV-APS (355-nm excitation) increased with time for both BtAH and MS2 aerosols. A two log loss of MS2 bacteriophage infectivity was observed in the presence of ozone at ~50% and 80% RH when measured by culture and normalized for physical losses by q-PCR. Viability of BtAH spores after exposure could not be measured due to the loss of genomic material during experiments, suggesting degradation of extracelluar DNA attributable to oxidation. The results of these studies indicate that the physical and biological properties of bioaerosols change significantly after exposure to ozone and water vapor.

  1. Fluorescence spectra and biological activity of aerosolized bacillus spores and MS2 bacteriophage exposed to ozone at different relative humidities in a rotating drum

    DOE PAGESBeta

    Ratnesar-Shumate, Shanna; Pan, Yong-Le; Hill, Steven C.; Kinahan, Sean; Corson, Elizabeth; Eshbaugh, Jonathan; Santarpia, Joshua L.

    2015-10-14

    Biological aerosols (bioaerosols) released into the environment may undergo physical and chemical transformations when exposed to atmospheric constituents such as solar irradiation, reactive oxygenated species, ozone, free radicals, water vapor and pollutants. Aging experiments were performed in a rotating drum chamber subjecting bioaerosols, Bacillus thuringiensis Al Hakam (BtAH) spores and MS2 bacteriophages to ozone at 0 and 150 ppb, and relative humidities (RH) at 10%, 50%, and 80+%. Fluorescence spectra and intensities of the aerosols as a function of time in the reaction chamber were measured with a single particle fluorescence spectrometer (SPFS) and an Ultra-Violet Aerodynamic Particle Sizer® Spectrometermore » (UV-APS). Losses in biological activity were measured by culture and quantitative polymerase chain reaction (q-PCR) assay. For both types of aerosols the largest change in fluorescence emission was between 280 and 400 nm when excited at 263 nm followed by fluorescence emission between 380 and 700 nm when excited at 351 nm. The fluorescence for both BtAH and MS2 were observed to decrease significantly at high ozone concentration and high RH when excited at 263 nm excitation. The decreases in 263 nm excited fluorescence are indicative of hydrolysis and oxidation of tryptophan in the aerosols. Fluorescence measured with the UV-APS (355-nm excitation) increased with time for both BtAH and MS2 aerosols. A two log loss of MS2 bacteriophage infectivity was observed in the presence of ozone at ~50% and 80% RH when measured by culture and normalized for physical losses by q-PCR. Viability of BtAH spores after exposure could not be measured due to the loss of genomic material during experiments, suggesting degradation of extracelluar DNA attributable to oxidation. The results of these studies indicate that the physical and biological properties of bioaerosols change significantly after exposure to ozone and water vapor.« less

  2. Fluorescence spectra and biological activity of aerosolized bacillus spores and MS2 bacteriophage exposed to ozone at different relative humidities in a rotating drum

    NASA Astrophysics Data System (ADS)

    Ratnesar-Shumate, Shanna; Pan, Yong-Le; Hill, Steven C.; Kinahan, Sean; Corson, Elizabeth; Eshbaugh, Jonathan; Santarpia, Joshua L.

    2015-03-01

    Biological aerosols (bioaerosols) released into the environment may undergo physical and chemical transformations when exposed to atmospheric constituents such as solar irradiation, reactive oxygenated species, ozone, free radicals, water vapor and pollutants. Aging experiments were performed in a rotating drum chamber subjecting bioaerosols, Bacillus thuringiensis Al Hakam (BtAH) spores and MS2 bacteriophages to ozone at 0 and 150 ppb, and relative humidities (RH) at 10%, 50%, and 80+%. Fluorescence spectra and intensities of the aerosols as a function of time in the reaction chamber were measured with a single particle fluorescence spectrometer (SPFS) and an Ultra-Violet Aerodynamic Particle Sizer® Spectrometer (UV-APS). Losses in biological activity were measured by culture and quantitative polymerase chain reaction (q-PCR) assay. For both types of aerosols the largest change in fluorescence emission was between 280 and 400 nm when excited at 263 nm followed by fluorescence emission between 380 and 700 nm when excited at 351 nm. The fluorescence for both BtAH and MS2 were observed to decrease significantly at high ozone concentration and high RH when excited at 263 nm excitation. The decreases in 263 nm excited fluorescence are indicative of hydrolysis and oxidation of tryptophan in the aerosols. Fluorescence measured with the UV-APS (355-nm excitation) increased with time for both BtAH and MS2 aerosols. A two log loss of MS2 bacteriophage infectivity was observed in the presence of ozone at ~50% and 80% RH when measured by culture and normalized for physical losses by q-PCR. Viability of BtAH spores after exposure could not be measured due to the loss of genomic material during experiments, suggesting degradation of extracelluar DNA attributable to oxidation. The results of these studies indicate that the physical and biological properties of bioaerosols change significantly after exposure to ozone and water vapor.

  3. Three-dimensional dust aerosol distribution and extinction climatology over northern Africa simulated with the ALADIN numerical prediction model from 2006 to 2010

    NASA Astrophysics Data System (ADS)

    Mokhtari, M.; Tulet, P.; Fischer, C.; Bouteloup, Y.; Bouyssel, F.; Brachemi, O.

    2015-08-01

    The seasonal cycle and optical properties of mineral dust aerosols in northern Africa were simulated for the period from 2006 to 2010 using the numerical atmospheric model ALADIN (Aire Limitée Adaptation dynamique Développement InterNational) coupled to the surface scheme SURFEX (SURFace EXternalisée). The particularity of the simulations is that the major physical processes responsible for dust emission and transport, as well as radiative effects, are taken into account on short timescales and at mesoscale resolution. The aim of these simulations is to quantify the dust emission and deposition, locate the major areas of dust emission and establish a climatology of aerosol optical properties in northern Africa. The mean monthly aerosol optical thickness (AOT) simulated by ALADIN is compared with the AOTs derived from the standard Dark Target (DT) and Deep Blue (DB) algorithms of the Aqua-MODIS (MODerate resolution Imaging Spectroradiometer) products over northern Africa and with a set of sun photometer measurements located at Banizoumbou, Cinzana, Soroa, Mbour and Cape Verde. The vertical distribution of dust aerosol represented by extinction profiles is also analysed using CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) observations. The annual dust emission simulated by ALADIN over northern Africa is 878 Tg year-1. The Bodélé Depression appears to be the main area of dust emission in northern Africa, with an average estimate of about 21.6 Tg year-1. The simulated AOTs are in good agreement with satellite and sun photometer observations. The positions of the maxima of the modelled AOTs over northern Africa match the observed positions, and the ALADIN simulations satisfactorily reproduce the various dust events over the 2006-2010 period. The AOT climatology proposed in this paper provides a solid database of optical properties and consolidates the existing climatology over this region derived from satellites, the AERONET network and regional climate

  4. Time-Resolved Molecular Characterization of Limonene/Ozone Aerosol using High-Resolution Electrospray Ionization Mass Spectrometry

    SciTech Connect

    Bateman, Adam P.; Nizkorodov, Serguei; Laskin, Julia; Laskin, Alexander

    2009-09-09

    Molecular composition of limonene/O3 secondary organic aerosol (SOA) was investigated using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) as a function of reaction time. SOA was generated by ozonation of D-limonene in a reaction chamber and sampled at different time intervals using a cascade impactor. The SOA samples were extracted into acetonitrile and analyzed using a HR-ESI-MS instrument with a resolving power of 100,000 (m/Δm). The resulting mass spectra provided detailed information about the extent of oxidation inferred from the O:C ratios, double bond equivalency (DBE) factors, and aromaticity indexes (AI) in hundreds of identified individual SOA species.

  5. Cloud acidity and acidic deposition in the lower troposphere and ozone depletion in the Antarctic stratosphere: Modeling and data analysis regarding the role of atmospheric aerosol

    SciTech Connect

    Lin, Nenghuei.

    1991-01-01

    This study focused on the role of atmospheric aerosols in determining the cloud acidity and acidic deposition in the lower troposphere and the ozone depletion in the Antarctic stratosphere. For the former, a cloud chemistry model is developed to study the in-cloud chemistry and acidity in cloud droplets. The cloud chemistry model includes the absorption of trace gases, the oxidation of aqueous phase SO{sub 2}, and the scavenging of atmospheric aerosols. A new scheme is developed to differentiate the acidity and chemical composition distributing in individual cloud droplets. The above cloud chemistry model is incorporated into a two-layer flow model in order to investigate the effects of mountain waves on the cloud acidity. Using the three-year database acquired at Mt. Mitchell site, the in-cloud chemistry and acidic deposition through dry, wet and cloud deposition pathways are investigated. The in-cloud scavenging of submicron aerosols such as sulfates and nitrates is parameterized as a function of cloud deposition rate. The deposition fluxes of sulfur (S) compounds are found primarily contributed by cloud capture mechanism followed by incident precipitation and dry deposition. A comparison of deposition estimates at Mt. Mitchell with those at other sites shows that the sulfate deposition at sites exceeding 1,200 m MSL in elevation in Bavaria (Germany) and eastern USA is almost identical within error limits. The features of the Antarctic stratospheric aerosols during the ozone depletion episode of October 1987 are investigated based on the SAGE 2 (Stratospheric Aerosol and Gas Experiment 2) data. The study focuses on (1) inferring the aerosol size spectrum using a modified randomized minimization-search-technique (RMST), and (2) investigating the vertical, zonal and columnar averages of aerosol properties, together with the ozone concentration.

  6. Photodegradation of secondary organic aerosol generated from limonene oxidation by ozone studied with chemical ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Pan, X.; Underwood, J. S.; Xing, J.-H.; Mang, S. A.; Nizkorodov, S. A.

    2009-06-01

    Photodegradation of secondary organic aerosol (SOA) prepared by ozone-initiated oxidation of D-limonene is studied with an action spectroscopy approach, which relies on detection of volatile photoproducts with chemical ionization mass-spectrometry as a function of the UV irradiation wavelength. Efficient photodegradation is observed for a broad range of ozone (0.1-300 ppm) and D-limonene (0.02-3 ppm) concentrations used in the preparation of SOA. The observed photoproducts are dominated by oxygenated C1-C3 compounds such as methanol, formic acid, acetaldehyde, acetic acid, and acetone. The irradiation wavelength dependence of the combined yield of the photoproducts closely tracks the absorption spectrum of the SOA material suggesting that photodegradation is not limited to the UV wavelengths. Kinetic simulations suggest that RO2+HO2/RO2 reactions represent the dominant route to photochemically active carbonyl and peroxide species in the limonene SOA prepared in these experiments. Similar photodegradation processes are likely to occur in realistic SOA produced by OH- or O3-initiated oxidation of biogenic volatile organic compounds in clean air.

  7. Photodegradation of secondary organic aerosol generated from limonene oxidation by ozone studied with chemical ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Pan, X.; Underwood, J. S.; Xing, J.-H.; Mang, S. A.; Nizkorodov, S. A.

    2009-02-01

    Photodegradation of secondary organic aerosol (SOA) prepared by ozone-initiated oxidation of D-limonene is studied with an action spectroscopy approach, which relies on detection of volatile photoproducts with chemical ionization mass-spectrometry as a function of the UV irradiation wavelength. Efficient photodegradation is observed for a broad range of ozone and D-limonene concentrations (0.1-300 ppm) used in the preparation of SOA. The observed photoproducts are dominated by oxygenated C1-C3 compounds such as methanol, formic acid, acetaldehyde, acetic acid, and acetone. The irradiation wavelength dependence of the combined yield of the photoproducts closely tracks the absorption spectrum of the SOA material suggesting that photodegradation is not limited to the UV wavelengths. Kinetic simulations suggest that RO2+HO2/RO2 reactions represent the dominant route to photochemically active carbonyl and peroxide species in the limonene SOA material. Similar photodegradation processes are likely to occur in realistic SOA produced by OH- or O3-initiated oxidation of biogenic volatile organic compounds in clean air.

  8. Aerosol physical properties in the stratosphere (APPS) radiometer design

    NASA Technical Reports Server (NTRS)

    Gray, C. R.; Woodin, E. A.; Anderson, T. J.; Magee, R. J.; Karthas, G. W.

    1977-01-01

    The measurement concepts and radiometer design developed to obtain earth-limb spectral radiance measurements for the Aerosol Physical Properties in the Stratosphere (APPS) measurement program are presented. The measurements made by a radiometer of this design can be inverted to yield vertical profiles of Rayleigh scatterers, ozone, nitrogen dioxide, aerosol extinction, and aerosol physical properties, including a Junge size-distribution parameter, and a real and imaginary index of refraction. The radiometer design provides the capacity for remote sensing of stratospheric constituents from space on platforms such as the space shuttle and satellites, and therefore provides for global measurements on a daily basis.

  9. Raman Lidar Measurements of Aerosol Extinction and Backscattering. Report 2; Derivation of Aerosol Real Refractive Index, Single-Scattering Albedo, and Humidification Factor using Raman Lidar and Aircraft Size Distribution

    NASA Technical Reports Server (NTRS)

    Ferrare, R. A.; Melfi, S. H.; Whiteman, D. N.; Evans, K. D.; Poellot, M.; Kaufman, Y. J.

    1998-01-01

    Aerosol backscattering and extinction profiles measured by the NASA Goddard Space Flight Center Scanning Raman Lidar (SRL) during the remote cloud sensing (RCS) intensive operations period (IOP) at the Department of Energy Atmospheric Radiation Measurement (ARM) southern Great Plains (SGP) site during two nights in April 1994 are discussed. These profiles are shown to be consistent with the simultaneous aerosol size distribution measurements made by a PCASP (Passive Cavity Aerosol Spectrometer Probe) optical particle counter flown on the University of North Dakota Citation aircraft. We describe a technique which uses both lidar and PCASP measurements to derive the dependence of particle size on relative humidity, the aerosol real refractive index n, and estimate the effective single-scattering albedo Omega(sub 0). Values of n ranged between 1.4-1.5 (dry) and 1.37-1.47 (wet); Omega(sub 0) varied between 0.7 and 1.0. The single-scattering albedo derived from this technique is sensitive to the manner in which absorbing particles are represented in the aerosol mixture; representing the absorbing particles as an internal mixture rather than the external mixture assumed here results in generally higher values of Omega(sub 0). The lidar measurements indicate that the change in particle size with relative humidity as measured by the PCASP can be represented in the form discussed by Hattel with the exponent gamma = 0.3 + or - 0.05. The variations in aerosol optical and physical characteristics captured in the lidar and aircraft size distribution measurements are discussed in the context of the meteorological conditions observed during the experiment.

  10. Ozone, aerosol, potential vorticity, and trace gas trends observed at high-latitudes over North America from February to May 2000

    NASA Astrophysics Data System (ADS)

    Browell, Edward V.; Hair, Johnathan W.; Butler, Carolyn F.; Grant, William B.; Deyoung, Russell J.; Fenn, Marta A.; Brackett, Vince G.; Clayton, Marian B.; Brasseur, Lorraine A.; Harper, David B.; Ridley, Brian A.; Klonecki, Andrzej A.; Hess, Peter G.; Emmons, Louisa K.; Tie, Xuexi; Atlas, Elliot L.; Cantrell, Christopher A.; Wimmers, Anthony J.; Blake, Donald R.; Coffey, Michael T.; Hannigan, James W.; Dibb, Jack E.; Talbot, Robert W.; Flocke, Frank; Weinheimer, Andrew J.; Fried, Alan; Wert, Bryan; Snow, Julie A.; Lefer, Barry L.

    2003-02-01

    Ozone (O3) and aerosol scattering ratio profiles were obtained from airborne lidar measurements on thirty-eight flights over seven deployments covering the latitudes of 40°-85°N between 4 February and 23 May 2000 as part of the Tropospheric Ozone Production about the Spring Equinox (TOPSE) field experiment. Each deployment started from Broomfield, Colorado, with bases in Churchill, Canada, and on most deployments, Thule Air Base, Greenland. Nadir and zenith lidar O3 measurements were combined with in situ O3 measurements to produce vertically continuous O3 profiles from near the surface to above the tropopause. Potential vorticity (PV) distributions along the flight track were obtained from several different meteorological analyses. Ozone, aerosol, and PV distributions were used together to identify the presence of pollution plumes and stratospheric intrusions. Ozone was found to increase in the middle free troposphere (4-6 km) at high latitudes (60°-85°N) by an average of 4.6 ppbv/mo (parts per billion by volume per month) from about 54 ppbv in early February to over 72 ppbv in mid-May. The average aerosol scattering ratios at 1064 nm in the same region increased rapidly at an average rate of 0.36/mo from about 0.38 to over 1.7. Ozone and aerosol scattering were highly correlated over the entire field experiment, and PV and beryllium (7Be) showed no significant positive trend over the same period. The primary cause of the observed O3 increase in the mid troposphere at high latitudes was determined to be the photochemical production of O3 in pollution plumes with less than 20% of the increase from stratospherically-derived O3.

  11. Substitutes for ozone depleting aerosol electrical contact cleaners and cleaner/lubricants. Technical report

    SciTech Connect

    Bevilacqua, P.; Clark, K.G.

    1996-01-24

    With the production of Class I Ozone Depleting Substances discontinued as of January 1996, it became necessary to identify suitable replacements for chlorofluorocarbon (CFC-113) and trichloroethane (TCA) based electrical contact cleaners and cleaner/lubricant products. Two hydrochlorofluorocarbon (HCFC-141b) blends were identified as substitutes and recommended for interim use.

  12. An Evaluation of the Quality of Halogen Occultation Experiment Ozone Profiles in the Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Bhatt, Praful P.; Remsberg, Ellis E.; Gordley, Larry L.; McInerney, Joseph M.; Brackett, Vince G.; Russell, James M., III

    1999-01-01

    The archived ozone profiles from the Halogen Occultation Experiment (HALOE) have already been corrected for the effects of the spectrally varying, interfering absorption due to aerosols composed of aqueous sulfuric acid, and agreement with correlative measurements in the stratosphere is generally excellent. However, comparisons of sets of coincident HALOE and ozonesonde profiles indicate occasional large differences at the lowest levels of the stratosphere. Most of those instances occur at altitudes just below a well-defined minimum in the 5.26 microns channel aerosol extinction profile, whose wavelength dependence is not represented by a sulfuric acid aerosol model. Further, when the aerosol extinction exceeds about 10(exp 3)/ km, the aerosol correction to the ozone channel transmittances is both large and uncertain. After screening out the HALOE ozone profile segments whose corresponding aerosol/cirrus corrections are likely uncertain and after averaging lie ozonesonde profiles into 2.5 km thick layers, we find that the HALOE ozone areas, on average, to within 10% of their coincident ozonesonde measurements down to 100 hPa at tropical/subtropical latitudes and to 200 hPa at extratropical latitudes. A tightening of the coincidence criteria for the comparisons does not improve the mean differences for the sets nearly as much. Part of the variance of the paired differences was also accounted for when the ozonesonde profile values were integrated into those 2.5 km layers, prior to taking differences. This improvement is due mainly to the vertical averaging of the local, higher-resolution ozonesonde data, matching the lower resolution for HALOE ozone in the lower stratosphere. It is concluded that HALOE is providing accurate ozone profiles throughout the lower stratosphere, when its correction for interfering aerosols has been well characterized and when cirrus layers are not indicated.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  15. Algorithm improvement and validation of National Institute for Environmental Studies ozone differential absorption lidar at the Tsukuba Network for Detection of Stratospheric Change complementary station.

    PubMed

    Park, Chan Bong; Nakane, Hideaki; Sugimoto, Nobuo; Matsui, Ichiro; Sasano, Yasuhiro; Fujinuma, Yasumi; Ikeuchi, Izumi; Kurokawa, Jun-Ichi; Furuhashi, Noritaka

    2006-05-20

    Recently, a data processing and retrieval algorithm (version 2) for ozone, aerosol, and temperature lidar measurements was developed for an ozone lidar system at the National Institute for Environmental Studies (NIES) in Tsukuba (36 degrees N,140 degrees E), Japan. A method for obtaining the aerosol boundary altitude and the aerosol extinction-to-backscatter ratio in the version 2 algorithm enables a more accurate determination of the vertical profiles of aerosols and a more accurate correction of the systematic errors caused by aerosols in the vertical profile of ozone. Improvements in signal processing are incorporated for the correction of systematic errors such as the signal-induced noise and the dead-time effect. The mean vertical ozone profiles of the NIES ozone lidar were compared with those of the Stratospheric Aerosol and Gas Experiment II (SAGE II); they agreed well within a 5% relative difference in the 20-40 km altitude range and within 10% up to 45 km. The long-term variations in the NIES ozone lidar also showed good coincidence with the ozonesonde and SAGE II at 20, 25, 30, and 35 km. The temperatures retrieved from the NIES ozone lidar and those given by the National Center for Environmental Prediction agreed within 7 K in the 35-50 km range. PMID:16708104

  16. Reactive nitrogen, ozone, and nitrate aerosols observed in the Arctic stratosphere in January 1990

    NASA Technical Reports Server (NTRS)

    Kondo, Y.; Aimedieu, P.; Koike, M.; Iwasaka, Y.; Newman, P. A.; Schmidt, U.; Matthews, W. A.; Hayashi, M.; Sheldon, W. R.

    1992-01-01

    Ozone mixing ratios in the vicinity of the 525-K potential temperature surface in January and early February of 1990 were observed to decrease sharply across the edge of the vortex boundary, where the vortex position was estimated from Ertel's potential vorticity. The changes in NO(y) mixing ratio with respect to altitude measured on January 18 and 31 were quite well correlated with those of ozone between 15 and 24 km, indicating that NO(y) also had a large gradient across the edge of the vortex. This is interpreted as being mainly due to the significant denitrification that occurred inside the vortex. The total amount of gas and particulate phase HNO3 was close to the NO(y) amount at the altitude of the 22- to 23-km region, suggesting that the conversion of non-HNO3 reactive nitrogen to HNO3 had occurred with a PSC.

  17. Influence of ozone initiated processing on the toxicity of aerosol particles from small scale wood combustion

    NASA Astrophysics Data System (ADS)

    Nordin, Erik Z.; Uski, Oskari; Nyström, Robin; Jalava, Pasi; Eriksson, Axel C.; Genberg, Johan; Roldin, Pontus; Bergvall, Christoffer; Westerholm, Roger; Jokiniemi, Jorma; Pagels, Joakim H.; Boman, Christoffer; Hirvonen, Maija-Riitta

    2015-02-01

    Black carbon containing emissions from biomass combustion are being transformed in the atmosphere upon processing induced by tropospheric ozone and UV. The knowledge today is very limited on how atmospheric processing affects the toxicological properties of the emissions. The aim of this study was to investigate the influence of ozone initiated (dark) atmospheric processing on the physicochemical and toxicological properties of particulate emissions from wood combustion. Emissions from a conventional wood stove operated at two combustion conditions (nominal and hot air starved) were diluted and transferred to a chamber. Particulate matter (PM) was collected before and after ozone addition to the chamber using an impactor. Detailed chemical and physical characterization was performed on chamber air and collected PM. The collected PM was investigated toxicologically in vitro with a mouse macrophage model, endpoints included: cell cycle analysis, viability, inflammation and genotoxicity. The results suggest that changes in the organic fraction, including polycyclic aromatic hydrocarbons (PAHs) are the main driver for differences in obtained toxicological effects. Fresh hot air starved emissions containing a higher organic and PAH mass-fraction affected cell viability stronger than fresh emissions from nominal combustion. The PAH mass fractions decreased upon aging due to chemical degradation. Dark aging increased genotoxicity, reduced viability and reduced release of inflammatory markers. These differences were statistically significant for single doses and typically less pronounced. We hypothesize that the alterations in toxicity upon simulated dark aging in the atmosphere may be caused by reaction products that form when PAHs and other organic compounds react with ozone and nitrate radicals.

  18. Measurements of Vertical Profiles of Turbulence, Temperature, Ozone, Aerosols, and BrO over Sea Ice and Tundra Snowpack during BROMEX

    NASA Astrophysics Data System (ADS)

    Shepson, P.; Caulton, D.; Cambaliza, M. L.; Dhaniyala, S.; Fuentes, J. D.; General, S.; Halfacre, J. W.; Nghiem, S. V.; Perez Perez, L.; Peterson, P. K.; Platt, U.; Pohler, D.; Pratt, K. A.; Simpson, W. R.; Stirm, B.; Walsh, S. J.; Zielcke, J.

    2012-12-01

    During the BROMEX field campaign of March 2012, we conducted measurements of boundary layer structure, ozone, BrO and aerosol, from a light, twin-engine aircraft during eleven flights originating from Barrow, AK. Flights were conducted over the sea ice in the Beaufort and Chukchi Seas, and over the tundra from Barrow to the Brooks Range, with vertical profiles covering altitudes from the surface to 3.5km in the free troposphere. Flights over the course of one month allowed a variety of sea ice conditions, including open water, nilas, first year sea ice, and frost flowers, to be examined over the Chukchi Sea. Atmospheric turbulence was measured using a calibrated turbulence probe, which will enable characterization of both the structure and turbulence of the Arctic boundary layer. Ozone was measured using a 2B UV absorption instrument. A GRIMM optical particle counter was used to measure 0.25-4 μm sized aerosol particles. The MAX-DOAS instrument enabled measurements of BrO vertical profiles. The aircraft measurements can be used to connect the surface measurements of ozone and BrO from the "Icelander" buoys, and the surface sites at Barrow, with those measured on the aircraft. Here we will discuss the spatial variability/coherence in these data. A major question that will be addressed using these data is the extent to which bromine is activated through reactions at the snowpack/ice surface versus the surface of aerosols. Here we will present a preliminary analysis of the relationships between snow/ice surface types, aerosol size-resolved number concentrations, and the vertical profiles of ozone and BrO.

  19. Simultaneous measurement of atmospheric temperature, humidity, and aerosol extinction and backscatter coefficients by a combined vibrational pure-rotational Raman lidar

    NASA Astrophysics Data System (ADS)

    Balin, I.; Serikov, I.; Bobrovnikov, S.; Simeonov, V.; Calpini, B.; Arshinov, Y.; van den Bergh, H.

    2004-10-01

    Implementation of the pure-rotational Raman (PRR) lidar method for simultaneous measurement of atmospheric temperature, humidity, and aerosol extinction and backscatter coefficients is reported. The isolation of two wavelength domains of the PRR spectrum and the suppression of the elastically scattered light is carried out by a double-grating polychromator. Experiments involving elastic backscatter from dense clouds and a solid target confirm the high level of suppression of the elastic light in the corresponding acquisition channels of the two selected PRR domains. Calibration of the temperature channel was done both by comparison with an experimentally verified atmospheric temperature model profile and by inter-comparison with radiosondes. Night-time temperature profiles with high vertical resolution were obtained up to the lower stratosphere. The PRR temperature profile combined with the water vapor mixing ratio obtained from the ro-vibrational Raman channel is used to estimate the relative humidity.

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

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  1. Characterization of radicals and high-molecular weight species from alpha-pinene/ozone reaction and ambient aerosol samples

    NASA Astrophysics Data System (ADS)

    Pavlovic, Jelica

    Secondary organic aerosol formed during oxidation of different volatile organic compounds is composed from a number of final and intermediate reaction products. The final products include compounds in both low and high molecular weight range called also oligomer species. These compounds can be highly volatile, as well as being semi- or low-volatility compounds. This study characterized intermediate reactive radical products formed from previously often studied alpha-pinene/ozone reaction. In order to passivate those radical species nitrone spin traps were used. 5,5-dimethyl-4,5-dihydro-3H-pyrrole-N-oxide (DMPO), and 5-dietoxyphosphoryl-5-methyl-1-pyrroline-N-oxide (DEPMPO) traps were able to successfully trap oxygen- and carbon-centered radicals produced from alpha-pinene/ozone reaction. Electrospray ionization (ESI) in negative ion mode with mass spectrometry (MS) detection was used to scan spectra of formed spin trap adducts and the tandem mass spectrometry (MSn) to elucidate its structures as well as structures of captured radicals. The same method was applied to analyze radical species present in ambient PM2.5 samples. Few carbon- (alkyl) and oxygen- (alkoxyl) centered radicals were captured with DMPO and DEPMPO traps. The second part of this study was focused on high molecular weight (high-MW) species formed from the same reaction (alpha-pinene/ozone), but found also in fine particulate matter fractions of ambient samples. LC/MS/MS analysis of dimer species from chamber study revealed fragments that can originate from peroxide structures. Proposed reaction for these peroxide dimer formation is self reaction of two peroxyl radicals, followed by the loss of oxygen molecule. These findings emphasize the role of peroxyl (ROO) radicals in formation of high-MW products and are in line with the high O:C ratio results reported in other studies. Water soluble organic carbon (WSOC) extracts of three size fractions of the ambient aerosol, PM1--2.5, PM0.1--1, and PM<0

  2. Condensation nuclei and aerosol-scattering extinction measurements at Mauna Loa Observatory: 1974-1985. Data report

    SciTech Connect

    Massey, D.M.; Quakenbush, T.K.; Bodhaine, B.A.

    1987-07-01

    The observatory at Mauna Loa, Hawaii measures the characteristics of surface aerosols under background conditions. The instruments provide data that are representative of the background-aerosol climatology at Mauna Loa. These data can also be used to identify potential local contamination periods. The nephelometer's light-scattering measurements show an annual cycle: a maximum in April and a minimum in November, with a variation of a factor of 5.5. The Condensation Nucleus (CN) counter shows a much smaller annual cycle: a maximum in September and a minimum in March, with a variation of a factor of 1.5. A local decrease in CN concentration occurs in August. The Angstrom exponent minimum occurs in May. This indicates larger aerosol particles within the month as compared with the remainder of the year.

  3. Simultaneous retrieval of total ozone column amounts and cloud/aerosol optical depths from multi-channel, moderate bandwidth filter instruments

    NASA Astrophysics Data System (ADS)

    Stamnes, Knut; Fan, Lingling; Li, Wei; Dahlback, Arne; Stamnes, Jakob; Stamnes, Snorre

    2015-04-01

    A new method is presented based on using neural networks (NN) to analyze ultraviolet (UV) irradiance data recorded by multi-channel, moderate bandwidth filter instruments. Application of the NN method to three years of data obtained by a NILU-UV multi-channel, moderate bandwidth filter instrument, revealed that compared to a traditional look-up table (LUT) method, the NN method yielded better agreement against the Ozone Monitoring Instrument (OMI) with a 1% decrease in relative difference and a significant increase in the correlation of total ozone column (TOC) values. Furthermore, this new method resulted in larger number of valid retrievals (daily average values within a meaningful range of 200-500 DU) than the LUT method. Compared with NN retrievals based on NILU-UV irradiance measurements, TOC values obtained from OMI were underestimated under cloudy conditions. Cloud optical depth (COD) values derived by the NN method were more reliable than corresponding results derived by the LUT method, the latter results were less accurate for heavy cloud cover, broken cloud situations or snow-covered ground. The potential for retrieving aerosol optical depth (AOD) values under cloud-free conditions will be discussed. The cloud-aerosol information obtained by irradiance instruments such as the NILU-UV can be used in conjunction with a radiative transfer model to estimate cloud/aerosol radiative forcing and hence the impact of clouds and aerosols on the radiative energy balance. Deployment of multi-channel, moderate bandwidth filter instruments at AERONET sites and analysis of such data in conjunction with AERONET and satellite remote sensing data can provide crucial information needed for the assessment of the influence of ozone, clouds, and aerosols on climate.

  4. SAGE (version 5.96) Ozone Trends in the Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Cunnold, D. M.; Wang, H. J.; Thomason, L. W.; Zawodny, J. M.; Logan, J. A.; Megretkaia, I. A.

    2002-01-01

    Ozone retrievals from Stratospheric Aerosol and Gas Experiment (SAGE) II version 5.96 (v5.96) below approx. 25 km altitude are discussed. This version of the algorithm includes improved constraints on the wavelength dependence of aerosol extinctions based on the ensemble of aerosol size distribution measurements. This results in a reduction of SAGE ozone errors in the 2 years after the Mount Pinatubo eruption. However, SAGE ozone concentrations are still approx. 10% larger than ozonesonde and Halogen Occultation Experiment (HALOE) measurements below 20 km altitude under nonvolcanic conditions (and by more than this in the tropics). The analysis by Steele and Turco suggests that the SAGE ozone overpredictions are in the wrong direction to be explained by aerosol extinction extrapolation errors. Moreover, preliminary SAGE 11 v6.0a retrievals suggest that they are partially accounted for by geometric difficulties at low altitudes in v5.96 and prior retrievals. SAGE ozone trends for the 1979-1996 and 1984-1996 periods are calculated and compared, and the sources of trend errors are discussed. These calculations are made after filtering out ozone data during periods of high, local aerosol extinctions. In the lower stratosphere, below approx. 28 km altitude, there is shown to be excellent agreement in the altitudinal structure of ozone decreases at 45 deg N between SAGE and ozonesondes with the largest decrease in both between 1979 and 1996 having occurred below 20 km altitude, amounting to 0.9 +/- 0.7% yr (2sigma) at 16 km altitude. However, in contrast to the fairly steady decreases at 45 deg N, both SAGE measurements and Lauder ozonesondes show ozone increases at 45 deg S over the period from the mid-1980s to 1996 of 0.2 +/- 0.5%/yr (2sigma) from 15 to 20 km altitude. The SAGE data suggest that this increase is a wintertime phenomenon which occurs in the 15-20 km height range. Changes in dynamics are suggested as the most likely cause of this increase. These

  5. Aging of secondary organic aerosol generated from the ozonolysis of α-pinene: effects of ozone, light and temperature

    NASA Astrophysics Data System (ADS)

    Denjean, C.; Formenti, P.; Picquet-Varrault, B.; Camredon, M.; Pangui, E.; Zapf, P.; Katrib, Y.; Giorio, C.; Tapparo, A.; Temime-Roussel, B.; Monod, A.; Aumont, B.; Doussin, J. F.

    2014-09-01

    A series of experiments was conducted in the CESAM simulation chamber to investigate the evolution of the physical and chemical properties of secondary organic aerosol (SOA) during different forcing. The present experiments represent a first attempt to comprehensively investigate the influence of oxidative processing, photochemistry, and diurnal temperature cycling upon SOA properties. SOA generated from the ozonolysis of α-pinene were exposed to (1) elevated ozone concentrations, (2) light (under controlled temperature conditions), or (3) light and heat (6 °C light-induced temperature increase), and the resultant changes in SOA optical properties (i.e. absorption and scattering), hygroscopicity and chemical composition were measured using a suite of instrumentation interfaced to the CESAM chamber. The complex refractive index (CRI) was derived from integrated nephelometer measurements at 525 nm wavelength, using Mie scattering calculations and measured number size distributions. The particle size growth factor (GF) was measured with a hygroscopic tandem differential mobility analyzer (H-TDMA). An aerosol mass spectrometer (AMS) was used for the determination of the f44 / f43 and O : C ratio of the particles bulk. No change in SOA size or chemical composition was observed during O3 and light exposure at constant temperature; in addition, GF and CRI of the SOA remained constant with forcing. By contrast, illumination of the SOA in the absence of temperature control led to an increase in the real part of the CRI from 1.35 (±0.03) to 1.49 (±0.03), an increase of the GF from 1.04 (±0.02) to 1.14 (±0.02) and an increase of the f44 / f43 ratio from 1.73 (±0.03) to 2.23 (±0.03). These surprising results suggest that SOA properties may be governed more by local temperature fluctuations than by oxidative processing and photochemistry.

  6. Relations between erythemal UV dose, global solar radiation, total ozone column and aerosol optical depth at Uccle, Belgium

    NASA Astrophysics Data System (ADS)

    De Bock, V.; De Backer, H.; Van Malderen, R.; Mangold, A.; Delcloo, A.

    2014-11-01

    At Uccle, Belgium, a long time series (1991-2013) of simultaneous measurements of erythemal ultraviolet (UV) dose (Sery), global solar radiation (Sg), total ozone column (QO3) and aerosol optical depth (τaer) (at 320.1 nm) is available, which allows for an extensive study of the changes in the variables over time. Linear trends were determined for the different monthly anomalies time series. Sery, Sg and QO3 all increase by respectively 7, 4 and 3% per decade. τaer shows an insignificant negative trend of -8% per decade. These trends agree with results found in the literature for sites with comparable latitudes. A change-point analysis, which determines whether there is a significant change in the mean of the time series, is applied to the monthly anomalies time series of the variables. Only for Sery and QO3, was a significant change point present in the time series around February 1998 and March 1998, respectively. The change point in QO3 corresponds with results found in the literature, where the change in ozone levels around 1997 is attributed to the recovery of ozone. A multiple linear regression (MLR) analysis is applied to the data in order to study the influence of Sg, QO3 and τaer on Sery. Together these parameters are able to explain 94% of the variation in Sery. Most of the variation (56%) in Sery is explained by Sg. The regression model performs well, with a slight tendency to underestimate the measured Sery values and with a mean absolute bias error (MABE) of 18%. However, in winter, negative Sery are modeled. Applying the MLR to the individual seasons solves this issue. The seasonal models have an adjusted R2 value higher than 0.8 and the correlation between modeled and measured Sery values is higher than 0.9 for each season. The summer model gives the best performance, with an absolute mean error of only 6%. However, the seasonal regression models do not always represent reality, where an increase in Sery is accompanied with an increase in QO3 and

  7. Relations between erythemal UV dose, global solar radiation, total ozone column and aerosol optical depth at Uccle, Belgium

    NASA Astrophysics Data System (ADS)

    De Bock, V.; De Backer, H.; Van Malderen, R.; Mangold, A.; Delcloo, A.

    2014-06-01

    At Uccle, a long time series (1991-2013) of simultaneous measurements of erythemal ultraviolet (UV) dose, global solar radiation, total ozone column (TOC) and Aerosol Optical Depth (AOD) (at 320.1 nm) is available which allows for an extensive study of the changes in the variables over time. A change-point analysis, which determines whether there is a significant change in the mean of the time series, is applied to the monthly anomalies time series of the variables. Only for erythemal UV dose and TOC, a significant change point (without any known instrumental cause) was present in the time series around February 1998 and March 1998 respectively. The change point in TOC corresponds with results found in literature, where the change in ozone levels (around 1997) is attributed to the recovery of ozone. Linear trends were determined for the different (monthly anomalies) time series. Erythemal UV dose, global solar radiation and TOC all increase with respectively 7, 4 and 3% per decade. AOD shows an (insignificant) negative trend of -8% per decade. These trends agree with results found in literature for sites with comparable latitudes. A multiple linear regression (MLR) analysis is applied to the data in order to study the influence of global solar radiation, TOC and AOD on the erythemal UV dose. Together these parameters are able to explain 94% of the variation in erythemal UV dose. Most of the variation (56%) in erythemal UV dose is explained by global solar radiation. The regression model performs well with a slight tendency to underestimate the measured erythemal UV doses and with a Mean Absolute Bias Error (MABE) of 18%. However, in winter, negative erythemal UV dose values are modeled. Applying the MLR to the individual seasons solves this issue. The seasonal models have an adjusted R2 value higher than 0.8 and the correlation between modeled and measured erythemal UV dose values is higher than 0.9 for each season. The summer model gives the best performance, with

  8. CU AMAX-DOAS applications in cloud-free and cloudy atmospheres: innovative Scattered Sun Light observations of trace gases and aerosol extinction

    NASA Astrophysics Data System (ADS)

    Volkamer, R.; Baidar, S.; Coburn, S.; Dix, B. K.; Oetjen, H.; Ortega, I.; Sinreich, R.; Atmospeclab

    2011-12-01

    An innovative airborne scanning multi-axis differential optical absorption spectroscopy (CU AMAX-DOAS) instrument has been developed at the University of Colorado, Boulder. The instrument collects scattered sunlight spectra in a sequence of discrete viewing angles, and employs the DOAS method (inherently calibrated, and selective) to simultaneously retrieve multiple trace gases, e.g., nitrogen dioxide (NO2), nitrous acid (HONO), formaldehyde (HCHO), glyoxal (CHOCHO), bromine oxide (BrO), iodine oxide (IO), chlorine dioxide (OClO), water vapor (H2O), and oxygen dimers (O4, at 360nm, 477nm, and 632nm) differential slant column densities (dSCD). Vertical profiles of these gases and multi-spectral aerosol extinction are inferred by combining Monte-Carlo Radiative Transfer Modelling (RTM) and optimal estimation techniques to construct a model atmosphere that can in principle represent 3D clouds and aerosols. The atmospheric state of this model atmosphere is constrained by observations of O4 dSCDs, Raman Scattering Probability (RSP), and intensity ratios, i.e., quantities that depend solely on relative intensity changes, without need for a direct sun view, or absolute radiance calibration. We show results from ongoing validation efforts (NOAA TwinOtter aircraft during CalNex and CARES), and demonstrate vertical profile retrievals (NSF/NCAR GV over the tropical Pacific Ocean) in both cloud-free and cloudy atmospheres.

  9. Aerosol measurements in the winter/spring Antarctic stratosphere. I - Correlative measurements with ozone. II - Impact on polar stratospheric cloud theories

    NASA Technical Reports Server (NTRS)

    Hofmann, D. J.; Rosen, J. M.; Harder, J. W.

    1988-01-01

    Aerosol measurements collected from August 25-November 3, 1986 at McMurdo Station using balloon-borne optical particle counters are examined in order to study the relationship between aerosol and ozone distribution and the formation of polar stratospheric clouds (PSCs). Ozone, aerosol, and condensation nuclei profiles, and pressure, temperature, and humidity measurements are analyzed. It is observed that the height of the stratospheric sulfate layer decreases over the period of measurement suggesting that upwelling in the votex is not important in the zone depletion process. Three theories on PSC formation are described, and the effects of the aerosol measurements on the theories are considered. The three theories are: (1) the original theory of water vapor pressure over a solution of H2SO4 of Steele et al. (1983) and Hamill and Mc Master (1984); (2) the nitric acid theory of PSCs of Toon et al. (1986) and Hamill et al. (1986); and (3) the quasi-cirrus cloud theory of Heymsfield (1986).

  10. Trace gas and aerosol sounding of the atmosphere using SAGE III

    NASA Astrophysics Data System (ADS)

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

    2003-04-01

    We present here the results of a new inversion procedure for SAGE (Stratospheric Aerosol and Gas Experiment) III, in which vertical profiles of ozone, NO2, and aerosol extinction are retrieved using the solar occultation technique. Our algorithm employs a very extensive set of simulated aerosol models, used as a priori information, to derive a pseudoempirical orthogonal basis set. In the retrieval algorithm, the spectral dependence of the aerosol extinction coefficient is then parameterized as an expansion in this basis set. A modeled covariance matrix is used for the ozone and NO2 vertical profiles. Statistical regularization (optimal estimation) is employed to derive the aerosol and gas extinctions. Simultaneous inversion of spectral and spatial components is performed yielding a combined retrieval of all unknown parameters. This algorithm has been successful in the interpretation of solar occultation experiments using the Ozon-Mir device on board the Russian Space Station, “Mir”. Here, results of numerical experiments of the error budget of this algorithm are presented for SAGE III. We compare our retrievals of the atmospheric constituents from SAGE III data with those of independent measurements.

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  12. Ozone uptake on glassy, semi-solid and liquid organic matter and the role of reactive oxygen intermediates in atmospheric aerosol chemistry.

    PubMed

    Berkemeier, Thomas; Steimer, Sarah S; Krieger, Ulrich K; Peter, Thomas; Pöschl, Ulrich; Ammann, Markus; Shiraiwa, Manabu

    2016-05-14

    Heterogeneous and multiphase reactions of ozone are important pathways for chemical ageing of atmospheric organic aerosols. To demonstrate and quantify how moisture-induced phase changes can affect the gas uptake and chemical transformation of organic matter, we apply a kinetic multi-layer model to a comprehensive experimental data set of ozone uptake by shikimic acid. The bulk diffusion coefficients were determined to be 10(-12) cm(2) s(-1) for ozone and 10(-20) cm(2) s(-1) for shikimic acid under dry conditions, increasing by several orders of magnitude with increasing relative humidity (RH) due to phase changes from amorphous solid over semisolid to liquid. Consequently, the reactive uptake of ozone progresses through different kinetic regimes characterised by specific limiting processes and parameters. At high RH, ozone uptake is driven by reaction throughout the particle bulk; at low RH it is restricted to reaction near the particle surface and kinetically limited by slow diffusion and replenishment of unreacted organic molecules. Our results suggest that the chemical reaction mechanism involves long-lived reactive oxygen intermediates, likely primary ozonides or O atoms, which may provide a pathway for self-reaction and catalytic destruction of ozone at the surface. Slow diffusion and ozone destruction can effectively shield reactive organic molecules in the particle bulk from degradation. We discuss the potential non-orthogonality of kinetic parameters, and show how this problem can be solved by using comprehensive experimental data sets to constrain the kinetic model, providing mechanistic insights into the coupling of transport, phase changes, and chemical reactions of multiple species in complex systems. PMID:27095585

  13. NMOC, ozone, and organic aerosol in the southeastern United States, 1999-2007: 3. Origins of organic aerosol in Atlanta, Georgia, and surrounding areas

    NASA Astrophysics Data System (ADS)

    Blanchard, C. L.; Hidy, G. M.; Tanenbaum, S.; Edgerton, E. S.

    2011-02-01

    Carbonaceous compounds constitute a major fraction of the fine particle mass at locations throughout North America; much of the condensed-phase organic carbon (OC) is produced in the atmosphere from NMOC reactions as "secondary" OC (SOC). Ten years of particulate carbon and speciated non-methane organic compound (NMOC) data combined with other measurements from Southeastern Aerosol Research and Characterization (SEARCH) and other sites provide insight into the association between elemental carbon (EC), OC and NMOCs. Data are analyzed to characterize the OC and SOC contrasts between urban Atlanta, Georgia, and nearby non-urban conditions in the Southeast. Analysis of the monitoring record indicates that the mean Atlanta urban excess of total carbon (TC) is 2.1-2.8 μg m -3. The OC/EC ratio of the Atlanta urban excess is in the range 1.3 to 1.8, consistent with OC/EC ratios observed in motor vehicle emissions and a fossil carbon source of urban excess TC. Carbon isotope analysis of a subset of particle samples demonstrates that the urban excess is mainly fossil in origin, even though the majority of the TC is modern at both urban and non-urban sites. Temperature-dependent partitioning of OC between gas and condensed phases cannot explain the observed diurnal and seasonal variations of OC/CO, EC/CO, and OC/EC ratios. Alternatively, a hypothesis involving vertical mixing of OC-enriched air from aloft is supported by the seasonal and diurnal OC, isopentane, aromatic and isoprene observations at the ground. A statistical model is applied to indicate the relative significance of aerometric factors affecting OC and EC concentrations, including meteorological and pollutant associations. The model results demonstrate strong linkages between fine particle carbon and pollutant indicators of source emissions compared with meteorological factors; the model results show weaker dependence of OC on meteorological factors than is the case for ozone (O 3) concentrations.

  14. Aerosol Retrievals from ARM SGP MFRSR Data

    DOE Data Explorer

    Alexandrov, Mikhail

    2008-01-15

    The Multi-Filter Rotating Shadowband Radiometer (MFRSR) makes precise simultaneous measurements of the solar direct normal and diffuse horizontal irradiances at six wavelengths (nominally 415, 500, 615, 673, 870, and 940 nm) at short intervals (20 sec for ARM instruments) throughout the day. Time series of spectral optical depth are derived from these measurements. Besides water vapor at 940 nm, the other gaseous absorbers within the MFRSR channels are NO2 (at 415, 500, and 615 nm) and ozone (at 500, 615, and 670 nm). Aerosols and Rayleigh scattering contribute atmospheric extinction in all MFRSR channels. Our recently updated MFRSR data analysis algorithm allows us to partition the spectral aerosol optical depth into fine and coarse modes and to retrieve the fine mode effective radius. In this approach we rely on climatological amounts of NO2 from SCIAMACHY satellite retrievals and use daily ozone columns from TOMS.

  15. Modeling ozone and aerosol formation and transport in the pacific northwest with the community Multi-Scale Air Quality (CMAQ) modeling system.

    PubMed

    O'Neill, Susan M; Lamb, Brian K; Chen, Jack; Claiborn, Candis; Finn, Dennis; Otterson, Sally; Figueroa, Cristiana; Bowman, Clint; Boyer, Mike; Wilson, Rob; Arnold, Jeff; Aalbers, Steven; Stocum, Jeffrey; Swab, Christopher; Stoll, Matt; Dubois, Mike; Anderson, Mary

    2006-02-15

    The Community Multi-Scale Air Quality (CMAQ) modeling system was used to investigate ozone and aerosol concentrations in the Pacific Northwest (PNW) during hot summertime conditions during July 1-15, 1996. Two emission inventories (El) were developed: emissions for the first El were based upon the National Emission Trend 1996 (NET96) database and the BEIS2 biogenic emission model, and emissions for the second El were developed through a "bottom up" approach that included biogenic emissions obtained from the GLOBEIS model. The two simulations showed that elevated PM2.5 concentrations occurred near and downwind of the Interstate-5 corridor along the foothills of the Cascade Mountains and in forested areas of central Idaho. The relative contributions of organic and inorganic aerosols varied by region, but generally organic aerosols constituted the largest fraction of PM2.5. In wilderness areas near the 1-5 corridor, organic carbon from anthropogenic sources contributed approximately 50% of the total organic carbon with the remainder from biogenic precursors, while in wilderness areas in Idaho, biogenic organic carbon accounted for 80% of the total organic aerosol. Regional analysis of the secondary organic aerosol formation in the Columbia River Gorge, Central Idaho, and the Olympics/Puget Sound showed that the production rate of secondary organic carbon depends on local terpene concentrations and the local oxidizing capacity of the atmosphere, which was strongly influenced by anthropogenic emissions. Comparison with observations from 12 IMPROVE sites and 21 ozone monitoring sites showed that results from the two El simulations generally bracketed the average observed PM parameters and that errors calculated for the model results were within acceptable bounds. Analysis across all statistical parameters indicated that the NW-AIRQUEST El solution performed better at predicting PM2.5, PM1, and beta(ext) even though organic carbon PM was over-predicted, and the NET96 El

  16. Photochemical age of air pollutants, ozone, and secondary organic aerosol in transboundary air observed on Fukue Island, Nagasaki, Japan

    NASA Astrophysics Data System (ADS)

    Irei, Satoshi; Takami, Akinori; Sadanaga, Yasuhiro; Nozoe, Susumu; Yonemura, Seiichiro; Bandow, Hiroshi; Yokouchi, Yoko

    2016-04-01

    To better understand the secondary air pollution in transboundary air over westernmost Japan, ground-based field measurements of the chemical composition of fine particulate matter ( ≤ 1 µm), mixing ratios of trace gas species (CO, O3, NOx, NOy, i-pentane, toluene, and ethyne), and meteorological elements were conducted with a suite of instrumentation. The CO mixing ratio dependence on wind direction showed that there was no significant influence from primary emission sources near the monitoring site, indicating long- and/or mid-range transport of the measured chemical species. Despite the considerably different atmospheric lifetimes of NOy and CO, these mixing ratios were correlated (r2 = 0.67). The photochemical age of the pollutants, t[OH] (the reaction time × the mean concentration of OH radical during the atmospheric transport), was calculated from both the NOx / NOy concentration ratio (NOx / NOy clock) and the toluene / ethyne concentration ratio (hydrocarbon clock). It was found that the toluene / ethyne concentration ratio was significantly influenced by dilution with background air containing 0.16 ppbv of ethyne, causing significant bias in the estimation of t[OH]. In contrast, the influence of the reaction of NOx with O3, a potentially biasing reaction channel on [NOx] / [NOy], was small. The t[OH] values obtained with the NOx / NOy clock ranged from 2.9 × 105 to 1.3 × 108 h molecule cm-3 and were compared with the fractional contribution of the m/z 44 signal to the total signal in the organic aerosol mass spectra (f44, a quantitative oxidation indicator of carboxylic acids) and O3 mixing ratio. The comparison of t[OH] with f44 showed evidence for a systematic increase of f44 as t[OH] increased, an indication of secondary organic aerosol (SOA) formation. To a first approximation, the f44 increase rate was (1.05 ± 0.03) × 10-9 × [OH] h-1, which is comparable to the background-corrected increase rate observed during the New England Air Quality

  17. Aging of secondary organic aerosol generated from the ozonolysis of α-pinene: effects of ozone, light and temperature

    NASA Astrophysics Data System (ADS)

    Denjean, C.; Formenti, P.; Picquet-Varrault, B.; Camredon, M.; Pangui, E.; Zapf, P.; Katrib, Y.; Giorio, C.; Tapparo, A.; Temime-Roussel, B.; Monod, A.; Aumont, B.; Doussin, J. F.

    2015-01-01

    A series of experiments was conducted in the CESAM (French acronym for Experimental Multiphasic Atmospheric Simulation Chamber) simulation chamber to investigate the evolution of the physical and chemical properties of secondary organic aerosols (SOAs) during different forcings. The present experiments represent a first attempt to comprehensively investigate the influence of oxidative processing, photochemistry, and diurnal temperature cycling upon SOA properties. SOAs generated from the ozonolysis of α-pinene were exposed under dry conditions (< 1% relative humidity) to (1) elevated ozone concentrations, (2) light (under controlled temperature conditions) or (3) light and heat (6 °C light-induced temperature increase), and the resultant changes in SOA optical properties (i.e. absorption and scattering), hygroscopicity and chemical composition were measured using a suite of instrumentation interfaced to the CESAM chamber. The complex refractive index (CRI) was derived from integrated nephelometer measurements of 525 nm wavelength, using Mie scattering calculations and measured number size distributions. The particle size growth factor (GF) was measured with a hygroscopic tandem differential mobility analyzer (H-TDMA). An aerosol mass spectrometer (AMS) was used for the determination of the f44 / f43 and O : C ratio of the particles bulk. No change in SOA size or chemical composition was observed during O3 and light exposure at constant temperature; in addition, GF and CRI of the SOA remained constant with forcing. On the contrary, illumination of SOAs in the absence of temperature control led to an increase in the real part of the CRI from 1.35 (±0.03) to 1.49 (±0.03), an increase of the GF from 1.04 (±0.02) to 1.14 (±0.02) and an increase of the f44 / f43 ratio from 1.73 (±0.03) to 2.23 (±0.03). The simulation of the experiments using the master chemical mechanism (MCM) and the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere

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

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  19. Characteristics of dimethylsulfide, ozone, aerosols, and cloud condensation nuclei in air masses over the northwestern Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Nagao, Ippei; Matsumoto, Kiyoshi; Tanaka, Hiroshi

    1999-05-01

    Long-term measurements of several trace gases and aerosols were carried out from December 1994 to October 1996 at Ogasawara Hahajima Island over the northwestern Pacific Ocean. The continental impact on the concentrations of sulfur compounds, ozone (O3), and cloud condensation nuclei (CCN) was estimated on the basis of the classification of air mass into seven types by isentropic trajectory analysis. From May to October, the air mass originating from the central North Pacific Ocean is predominant and regarded as the clean marine air for the concentrations of sulfur compounds and CCN. From the results of the molar ratio of methane sulfonic acid to non-sea-salt sulfate (NSS) and the positive correlation between dimethylsulfide (DMS) and CCN in this air mass it can be concluded that DMS largely contributes to the production of NSS and CCN. On the other hand, continental and anthropogenic substances are preferably transported to the northwestern Pacific Ocean by the predominant continental air mass from November to March. The enhancement of concentrations by the outflow from the Asian continent are estimated by a factor of 2.8 for O3, 3.9 for SO2, 3.5 for CCN activated at 0.5% supersaturation (0.5% CCN), 4.7 for 1.0% CCN, and 5.5 for NSS. Moreover, the CCN supersaturation spectra are also affected by the continental substances resulting in factor 2 of enhancement of cloud droplet number concentration. The diurnal variations of DMS and O3 for each air mass show a pattern of daytime minimum and nighttime maximum, which are typically found in remote ocean, even though those amplitudes are different for each air mass. Consequently, it can be concluded that the influence of nitric oxides (NOx) for the daytime O3 production and nitrate (NO3) radical for the nighttime oxidation of DMS are small even in the continental air mass.

  20. Effect of particle water on ozone and secondary organic aerosol formation from benzene-NO2-NaCl irradiations

    NASA Astrophysics Data System (ADS)

    Wang, Yujie; Luo, Hao; Jia, Long; Ge, Shuangshuang

    2016-09-01

    Ozone (O3) and secondary organic aerosol (SOA) are important pollutants in the urban atmosphere. Benzene is one of the most important aromatic species in urban air, which could produce O3 and SOA in the presence of NOx (x = 1, 2) and UV light. A series of experiments was carried out to study the effect of particle water on O3 and SOA formation from benzene under various humid conditions in an indoor smog chamber. The results show that the peak O3 concentrations decreased with the increase of RH or the mass concentration of liquid NaCl particles. The peak O3 concentration reduced by 30% as RH increased from 9% to 87% with the similar initial concentrations of NaCl (about 46 μg m-3), and decreased by 10% as the initial NaCl concentrations increased from 36.0 μg m-3 to 152.1 μg m-3 at about 73% RH. The relationships between liquid water content (LWC) and O3 or SOA were investigated. The results show that LWC is the key factor that leads to an opposite effect on O3 and SOA formation from benzene. The peak O3 concentration exponentially decreased 37% as LWC0 increased from zero to 349.8 μg m-3. Heterogeneous reaction of dinitrogen pentoxide (N2O5) with particle water is the major reason for the decrease of O3. The yields of SOA increased from 5.2 to 10.5% as LWC0 increased from zero to 349.8 μg m-3. The relative intensities of bands Osbnd H, Cdbnd O, Csbnd OH and NO3- increased by 22.9, 6.8, 6.7 and 13.1 times respectively as compared with dry condition. Alcohols or hydrates are confirmed to be the major contributors to SOA with increasing LWC.

  1. Evolution of ozone, particulates, and aerosol direct radiative forcing in the vicinity of Houston using a fully coupled meteorology-chemistry-aerosol model

    NASA Astrophysics Data System (ADS)

    Fast, Jerome D.; Gustafson, William I.; Easter, Richard C.; Zaveri, Rahul A.; Barnard, James C.; Chapman, Elaine G.; Grell, Georg A.; Peckham, Steven E.

    2006-11-01

    A new fully coupled meteorology-chemistry-aerosol model is used to simulate the urban- to regional-scale variations in trace gases, particulates, and aerosol direct radiative forcing in the vicinity of Houston over a 5 day summer period. Model performance is evaluated using a wide range of meteorological, chemistry, and particulate measurements obtained during the 2000 Texas Air Quality Study. The predicted trace gas and particulate distributions were qualitatively similar to the surface and aircraft measurements with considerable spatial variations resulting from urban, power plant, and industrial sources of primary pollutants. Sulfate, organic carbon, and other inorganics were the largest constituents of the predicted particulates. The predicted shortwave radiation was 30 to 40 W m-2 closer to the observations when the aerosol optical properties were incorporated into the shortwave radiation scheme; however, the predicted hourly aerosol radiative forcing was still underestimated by 10 to 50 W m-2. The predicted aerosol radiative forcing was larger over Houston and the industrial ship channel than over the rural areas, consistent with surface measurements. The differences between the observed and simulated aerosol radiative forcing resulted from transport errors, relative humidity errors in the upper convective boundary layer that affect aerosol water content, secondary organic aerosols that were not yet included in the model, and uncertainties in the primary particulate emission rates. The current model was run in a predictive mode and demonstrates the challenges of accurately simulating all of the meteorological, chemical, and aerosol parameters over urban to regional scales that can affect aerosol radiative forcing.

  2. Experimental correlations for transient soot measurement in diesel exhaust aerosol with light extinction, electrical mobility and diffusion charger sensor techniques

    NASA Astrophysics Data System (ADS)

    Bermúdez, Vicente; Pastor, José V.; López, J. Javier; Campos, Daniel

    2014-06-01

    A study of soot measurement deviation using a diffusion charger sensor with three dilution ratios was conducted in order to obtain an optimum setting that can be used to obtain accurate measurements in terms of soot mass emitted by a light-duty diesel engine under transient operating conditions. The paper includes three experimental phases: an experimental validation of the measurement settings in steady-state operating conditions; evaluation of the proposed setting under the New European Driving Cycle; and a study of correlations for different measurement techniques. These correlations provide a reliable tool for estimating soot emission from light extinction measurement or from accumulation particle mode concentration. There are several methods and correlations to estimate soot concentration in the literature but most of them were assessed for steady-state operating points. In this case, the correlations are obtained by more than 4000 points measured in transient conditions. The results of the new two correlations, with less than 4% deviation from the reference measurement, are presented in this paper.

  3. Radiative aspects of Antarctic ozone hole in 1985

    NASA Technical Reports Server (NTRS)

    Akiyoshi, H.; Fujiwara, M.; Uryu, M.

    1988-01-01

    In order to investigate the radiative heating effects of aerosols during September - October, 1985, at Antarctica, researchers solved the radiative transfer equation using a one-dimensional model, which includes the absorption of solar energy by water vapor, carbon dioxide, ozone and aerosols, the thermal emission and absorption by the above species and in addition, Rayleigh and Mie scattering, and the surface scattering effects. In this calculation, they used data of ozone density, water vapor density and aerosol extinction at 0.385, 0.453, 0.525 and 1.02 mu m in the stratosphere obtained by SAGE II satellite and meteorological data from NOAA. Results show that the Antarctic stratosphere is nearly in radiative equilibrium during that period, if the effects of aerosols are excluded. It is also shown that the heating effects of aerosols are too small to cause effective upward motions, in spite of some ambiguous parameters such as aerosol composition. The parameter dependences of results are also discussed.

  4. The Cretaceous-Tertiary extinction: A lethal mechanism involving anhydrite target rocks

    USGS Publications Warehouse

    Brett, R.

    1992-01-01

    The Chicxulub Crater, Yucatan, Mexico, is a leading contender as the site for the impact event that caused the Cretaceous-Tertiary (K-T) extinctions. A considerable thickness of anhydrite (CaSO4) forms part of the target rock. High temperatures resulting from impact would drive SO2 off from the anhydrite. Hundreds of billions of tonnes of sulfuric acid aerosol would thus enter the stratosphere and cause considerable cooling of the Earth's surface, decrease photosynthesis by orders of magnitude, deplete the ozone layer, and permit increased UV radiation to reach the Earth's surface. Finally, the aerosol would fall back to Earth as acid rain and devastate land and some lacustrine biota and near-surface marine creatures. The presence of anhydrite in the Chicxulub target rock may thus help explain the many extinctions observed at the K-T boundary. ?? 1992.

  5. The Cretaceous-Tertiary extinction - A lethal mechanism involving anhydrite target rocks

    NASA Astrophysics Data System (ADS)

    Brett, Robin

    1992-09-01

    The Chicxulub Crater, Yucatan, Mexico, is a leading contender as the site for the impact event that caused the Cretaceous-Tertiary (K-T) extinctions. A considerable thickness of anhydrite (CaSO4) forms part of the target rock. High temperatures resulting from impact would drive SO2 off from the anhydrite. Hundreds of billions of tonnes of sulfuric acid aerosol would thus enter the stratosphere and cause considerable cooling of the earth's surface, decrease photosynthesis by orders of magnitude, deplete the ozone layer, and permit increased UV radiation to reach the earth's surface. Finally, the aerosol would fall back to earth as acid rain and devastate land and some lacustrine biota and near-surface marine creatures. The presence of anhydrite in the Chicxulub target rock may thus help explain the many extinctions observed at the K-T boundary.

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

    NASA Astrophysics Data System (ADS)

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

    1998-04-01

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

  7. What role do type I polar stratospheric cloud and aerosol parameterizations play in modelled lower stratospheric chlorine activation and ozone loss?

    NASA Astrophysics Data System (ADS)

    Sessler, J.; Good, P.; MacKenzie, A. R.; Pyle, J. A.

    1996-12-01

    The chlorine activation and subsequent ozone loss of the northern winter lower stratosphere have been modelled using different schemes for type I polar stratospheric clouds (PSCs) and sulphate aerosols. Type I PSCs were assumed to consist of either nitric acid trihydrate (NAT) at equilibrium, supercooled ternary solutions (STS) at equilibrium, or to follow a hysteresis cycle between frozen and liquid particles depending on the temperature history. The sulphate aerosol was assumed to be present as either liquid binary H2SO4/H2O aerosol (LBA) or as solid sulphuric acid tetrahydrate (SAT). Our box model integrations show that NAT and STS, representing the upper and lower limits of lower stratospheric chlorine activation, respectively, appear to destroy ozone equally efficiently after a cold PSC event (Tmin ≤ 190K at 50 mbar). For higher minimum temperatures, up to the equilibrium NAT point, there is significantly more ozone loss in the NAT scheme than in the STS scheme. On NAT, chlorine is activated directly by ClONO2 + HCl → 2Cl + HNO3, whereas on STS, indirect activation by ClONO2 + H2O → HOCl + HNO3 followed by HOCl + HCl → 2Cl + H2O, dominates. During the processing period, the indirect activation on STS will produce a temporary peak in HOCl. Box model integrations also show that direct chlorine activation is faster on SAT than on LBA, yielding significantly more ozone loss in air parcels which remain below the SAT melting point (215-220 K). Our single-layer chemical transport model simulations (θ = 465K) of the lower stratospheric chlorine activation during Arctic winter 1994/1995 show that chlorine is activated more quickly on NAT than on STS. However, in mid December 1994, when temperatures are low enough for substantial STS particle growth, maximum active chlorine becomes similar in both schemes and remains similar until the end of January 1995. A model integration which includes SAT produces up to 200 parts per trillion by volume more ClOx, inside

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  9. Aircraft measurements of ozone, NOx, CO, and aerosol concentrations in biomass burning smoke over Indonesia and Australia in October 1997: Depleted ozone layer at low altitude over Indonesia

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Yukitomo; Sawa, Yousuke; Makino, Yukio; Jensen, Jørgen B.; Gras, John L.; Ryan, Brian F.; Diharto, Sri; Harjanto, Hery

    The 1997 El Niño unfolded as one of the most sever El Niño Southern Oscillation (ENSO) events in this century and it coincided with massive biomass burning in the equatorial western Pacific region. To assess the influence on the atmosphere, aircraft observations of trace gases and aerosol were conducted over Kalimantan in Indonesia and Australia. Over Kalimantan in Indonesia, high concentrations of O3, NOx, CO, and aerosols were observed during the flight. Although the aerosol and NOx decreased with altitude, the O3 had the maximum concentration (80.5 ppbv) in the middle layer of the smoke haze and recorded very low concentrations (˜20 ppbv) in the lower smoke layer. This feature was not observed in the Australian smoke. We proposed several hypotheses for the low O3 concentration at low levels over Kalimantan. The most likely are lack of solar radiation and losses at the surface of aerosol particles.

  10. Evolution of Ozone, Particulates, and Aerosol Direct Radiative Forcing in the Vicinity of Houston Using a Fully Coupled Meteorology-Chemistry-Aerosol Model

    SciTech Connect

    Fast, Jerome D.; Gustafson, William I.; Easter, Richard C.; Zaveri, Rahul A.; Barnard, James C.; Chapman, Elaine G.; Grell, Georg; Peckham, S. E.

    2006-11-11

    A new fully-coupled meteorology-chemistry-aerosol model is used to simulate the urban to regional scale variations in trace gases, particulates, and aerosol direct radiative forcing in the vicinity of Houston over a five day summer period. Model performance is evaluated using a wide range of meteorological, chemistry, and particulate measurements obtained during 2000 Texas Air Quality Study. The predicted trace gas and particulate distributions were qualitatively similar to the surface and aircraft measurements with considerable spatial variations resulting from urban, power plant, and industrial sources of primary pollutants. Sulfate, organic carbon, and other inorganics were the largest constituents of the predicted particulates. The predicted shortwave radiation was 30 to 40 W m-2 closer to the observations when the aerosol optical properties were incorporated into the shortwave radiation scheme; however, the predicted hourly aerosol radiative forcing was still under-estimated by 10 to 50 W m-2. The predicted aerosol radiative forcing was larger over Houston and the industrial ship channel than over the rural areas, consistent with surface measurements. The differences between the observed and simulated aerosol radiative forcing resulted from transport errors, relative humidity errors in the upper convective boundary layer that affect aerosol water content, secondary organic aerosols that were not yet included in the model, and uncertainties in the primary particulate emission rates. The current model was run in a predictive mode and demonstrates the challenges of accurately simulating all of the meteorological, chemical, and aerosol parameters over urban to regional scales that can affect aerosol radiative forcing.

  11. Volcanic Aerosols from Satellites: Current and Emerging Capabilities

    NASA Astrophysics Data System (ADS)

    Bhartia, P. K.; McCormick, M. P.; Loughman, R. P.

    2015-12-01

    There are 5 instruments currently operating in space with capability to measure stratospheric aerosols. Two of these are lidar backscatter instruments (CALIOP & ISS/CATS) that provide high vertical resolution, day/night coverage, and polarization information to separate ice clouds from sulfate aerosols. Two are limb scattering instruments (OSIRIS & OMPS-LP) with high sensitivity to aerosols and provide extensive spatial coverage of the sunlit globe. And a Canadian solar occultation instrument (ACE-MAESTRO) measures aerosol extinction twice per orbit. Next year we are expecting the launch of the SAGE III instrument on ISS with capability to measure aerosol extinction and Angstrom Exponent (AE) at multiple wavelengths by solar and lunar occultation techniques. It also has limb scattering capability to provide spatial coverage between solar occultations. The 51.6˚ inclination of the ISS orbit will allow SAGE III to measure aerosol scattering across the gobe for a wide range of scattering angles. Therefore, ISS SAGE III has the capability to provide vertically resolved information about a wide variety of aerosol properties, potentially including aerosol extinction, size distribution, refractive index, and particle shape parameters, similar to the one provided by the ground-based almucantar technique. In our talk we will focus primarily on the synergy between the OMPS LP instrument that has been flying on the Suomi NPP satellite since October 2011 and ISS SAGE III. We will show how these measurements can be combined together to capture spatial and temporal evolution of aerosols and ozone in large volcanic plumes to validate models and to support field campaigns.

  12. The Truth about Stratospheric Aerosols: Key Results from SPARC`s Assessment of Stratospheric Aerosol Properties

    NASA Astrophysics Data System (ADS)

    Thomason, L. W.; Peter, T.

    2005-12-01

    Given the critical role it plays in ozone chemistry, the Assessment of Stratospheric Aerosol Properties (ASAP) has been carried out by the WCRP project on Stratospheric Process and their Role in Climate (SPARC). The objective of this report was to present a systematic analysis of the state of knowledge of stratospheric aerosols including their precursors. It includes an examination of precursor concentrations and trends, measurements of stratospheric aerosol properties, trends in those properties, and modeling their formation, transport, and distribution in both background and volcanic conditions. The assessment found that the dominant nonvolcanic stratospheric aerosol precursor gases are OCS, SO2, and tropospheric aerosol. Therefore, though SO2, human-related activities play a significant role in the observed background stratospheric aerosol. There is general agreement between measured OCS and modeling of its transformation to sulfate aerosol, and observed aerosols. However, there is a significant dearth of SO2 measurements, and the role of tropospheric SO2 in the stratospheric aerosol budget - while significant - remains a matter of some guesswork. The assessment also found that there is basic agreement between the various data sets and models particularly during periods of elevated loading. However, at background levels significant differences were found that indicate that substantial questions remain regarding the nature of stratospheric aerosol during these periods particularly in the lower stratosphere. For instance, during periods of very low aerosol loading significant differences exist between systems for key parameters including aerosol surface area density and extinction. At the same time, comparisons of models and satellite observations of aerosol extinction found good agreement at visible wavelengths above 20-25 km altitude region but are less satisfactory for infrared wavelengths. While there are some model short-comings relative to observations in

  13. Inversion of tropospheric profiles of aerosol extinction and HCHO and NO2 mixing ratios from MAX-DOAS observations in Milano during the summer of 2003 and comparison with independent data sets

    NASA Astrophysics Data System (ADS)

    Wagner, T.; Beirle, S.; Brauers, T.; Deutschmann, T.; Frieß, U.; Hak, C.; Halla, J. D.; Heue, K. P.; Junkermann, W.; Li, X.; Platt, U.; Pundt-Gruber, I.

    2011-12-01

    We present aerosol and trace gas profiles derived from MAX-DOAS observations. Our inversion scheme is based on simple profile parameterisations used as input for an atmospheric radiative transfer model (forward model). From a least squares fit of the forward model to the MAX-DOAS measurements, two profile parameters are retrieved including integrated quantities (aerosol optical depth or trace gas vertical column density), and parameters describing the height and shape of the respective profiles. From these results, the aerosol extinction and trace gas mixing ratios can also be calculated. We apply the profile inversion to MAX-DOAS observations during a measurement campaign in Milano, Italy, September 2003, which allowed simultaneous observations from three telescopes (directed to north, west, south). Profile inversions for aerosols and trace gases were possible on 23 days. Especially in the middle of the campaign (17-20 September 2003), enhanced values of aerosol optical depth and NO2 and HCHO mixing ratios were found. The retrieved layer heights were typically similar for HCHO and aerosols. For NO2, lower layer heights were found, which increased during the day. The MAX-DOAS inversion results are compared to independent measurements: (1) aerosol optical depth measured at an AERONET station at Ispra; (2) near-surface NO2 and HCHO (formaldehyde) mixing ratios measured by long path DOAS and Hantzsch instruments at Bresso; (3) vertical profiles of HCHO and aerosols measured by an ultra light aircraft. Depending on the viewing direction, the aerosol optical depths from MAX-DOAS are either smaller or larger than those from AERONET observations. Similar comparison results are found for the MAX-DOAS NO2 mixing ratios versus long path DOAS measurements. In contrast, the MAX-DOAS HCHO mixing ratios are generally higher than those from long path DOAS or Hantzsch instruments. The comparison of the HCHO and aerosol profiles from the aircraft showed reasonable agreement with

  14. Inversion of tropospheric profiles of aerosol extinction and HCHO and NO2 mixing ratios from MAX-DOAS observations in Milano during the summer of 2003 and comparison with independent data sets

    NASA Astrophysics Data System (ADS)

    Wagner, T.; Beirle, S.; Brauers, T.; Deutschmann, T.; Frieß, U.; Hak, C.; Halla, J. D.; Heue, K. P.; Junkermann, W.; Li, X.; Platt, U.; Pundt-Gruber, I.

    2011-06-01

    We present aerosol and trace gas profiles derived from MAX-DOAS observations. Our inversion scheme is based on simple profile parameterisations used as input for an atmospheric radiative transfer model (forward model). From a least squares fit of the forward model to the MAX-DOAS measurements, two profile parameters are retrieved including integrated quantities (aerosol optical depth or trace gas vertical column density), and parameters describing the height and shape of the respective profiles. From these results, the aerosol extinction and trace gas mixing ratios can also be calculated. We apply the profile inversion to MAX-DOAS observations during a measurement campaign in Milano, Italy, September 2003, which allowed simultaneous observations from three telescopes (directed to north, west, south). Profile inversions for aerosols and trace gases were possible on 23 days. Especially in the middle of the campaign (17-20 September 2003), enhanced values of aerosol optical depth and NO2 and HCHO mixing ratios were found. The retrieved layer heights were typically similar for HCHO and aerosols. For NO2, lower layer heights were found, which increased during the day. The MAX-DOAS inversion results are compared to independent measurements: (1) aerosol optical depth measured at an AERONET station at Ispra; (2) near-surface NO2 and HCHO (formaldehyde) mixing ratios measured by long path DOAS and Hantzsch instruments at Bresso; (3) vertical profiles of HCHO and aerosols measured by an ultra light aircraft. Depending on the viewing direction, the aerosol optical depths from MAX-DOAS are either smaller or larger than those from AERONET observations. Similar comparison results are found for the MAX-DOAS NO2 mixing ratios versus long path DOAS measurements. In contrast, the MAX-DOAS HCHO mixing ratios are generally higher than those from long path DOAS or Hantzsch instruments. The comparison of the HCHO and aerosol profiles from the aircraft showed reasonable agreement with

  15. Investigation of aerosol and cloud properties using multiwavelength Raman lidar measurements

    NASA Astrophysics Data System (ADS)

    Verghese, Sachin John

    Lidar measurements obtained during several field campaigns have provided an extensive dataset for investigating aerosol characteristics and cloud properties. In this thesis we use measurements of multi-wavelength optical extinction measured with a Raman lidar to infer aerosol and cloud particle size variations. Aerosol extinction depends on both size and number density of the scatterers. The optical extinction at different wavelengths depends on the sixth power of the size parameter for aerosols much smaller than the scattering wavelength, and on the second power of the size parameter for aerosols much larger than the wavelength. Changes in the density of a particular size aerosol lead to a proportional response. The extinction profiles at several wavelengths are simultaneously examined to study changes in the aerosol size distribution over an interesting range of sizes corresponding to accumulation-mode particles. Model calculations based on Mie scattering theory are compared with extinction profiles at different wavelengths, water vapor profiles, and other simultaneous measurements, to investigate the formation and dissipation of cloud structures. The optical scattering measurements from aerosols and cloud particles demonstrate that various characteristics of aerosols and visibility can be determined. We demonstrate the capability of the new technique using the multi-wavelength extinction ratios to profile information about changes in CCN particle size in the range of 50 nm to 0.5 mum. Examples taken from three different field campaigns demonstrate that changes in the size of the cloud particles during the different stages of growth and dissipation are observed in the multi-wavelength aerosol extinction using this technique. We also show the relationship that exists between particle size increase or decrease in cloud regions, based on the extinction coefficients and changes in relative humidity. The deliquescence relative humidity (DRH) is found to exert a strong

  16. The effect of water on gas-particle partitioning of secondary organic aerosol. Part I: α-pinene/ozone system

    NASA Astrophysics Data System (ADS)

    Cocker, David R., III; Clegg, Simon L.; Flagan, Richard C.; Seinfeld, John H.

    The effect of relative humidity (RH) on aerosol formation by the semi-volatile oxidation products of the α-pinene/O 3 system has been comprehensively studied. Experiments were performed in the presence of ammonium sulfate (aqueous, dry), ammonium bisulfate seed (aqueous, dry), and aqueous calcium chloride seed aerosols to ascertain their effect on the partitioning of the oxidation products. The yield of organic aerosol varies little with RH, and is not affected by the presence of dry inorganic salt aerosols. Aqueous salt aerosols reduce the yield of organic aerosol compared to that under seed-free or dry seed conditions. The degree of reduction is electrolyte dependent, with aqueous ammonium sulfate leading to the largest reduction and aqueous calcium chloride the smallest. Hygroscopic growth of the organic aerosol from <2% to 85% RH was also monitored, and could be satisfactorily represented as the sum of the individual contributions of the organic and inorganic fractions. The implications of the growth factor measurements for concentration/activity relationships of the condensed phase organic material (assuming a liquid solution) was explored. The formation of the organic aerosol was investigated using a simple two component model, and also one including the 12 product compounds identified in a previous study. The experimental results for <2% and 50% RH (without salt seed aerosols) could be satisfactorily predicted. However, the aqueous salt seed aerosols are predicted to increase the overall yield due to the dissolution of the organic compounds into the water associated with the seed aerosol—the opposite effect to that observed. The implications of two distinct phases existing the aerosol phase were investigated.

  17. [Characteristics and Parameterization for Atmospheric Extinction Coefficient in Beijing].

    PubMed

    Chen, Yi-na; Zhao, Pu-sheng; He, Di; Dong, Fan; Zhao, Xiu-juan; Zhang, Xiao-ling

    2015-10-01

    In order to study the characteristics of atmospheric extinction coefficient in Beijing, systematic measurements had been carried out for atmospheric visibility, PM2.5 concentration, scattering coefficient, black carbon, reactive gases, and meteorological parameters from 2013 to 2014. Based on these data, we compared some published fitting schemes of aerosol light scattering enhancement factor [ f(RH)], and discussed the characteristics and the key influence factors for atmospheric extinction coefficient. Then a set of parameterization models of atmospheric extinction coefficient for different seasons and different polluted levels had been established. The results showed that aerosol scattering accounted for more than 94% of total light extinction. In the summer and autumn, the aerosol hygroscopic growth caused by high relative humidity had increased the aerosol scattering coefficient by 70 to 80 percent. The parameterization models could reflect the influencing mechanism of aerosol and relative humidity upon ambient light extinction, and describe the seasonal variations of aerosol light extinction ability. PMID:26841588

  18. Rapid Formation of Molecular Bromine from Deliquesced NaBr Aerosol in the Presence of Ozone and UV Light

    EPA Science Inventory

    The formation of gas-phase bromine from aqueous sodium bromide aerosols is investigated through a combination of chamber experiments and chemical kinetics modeling. Experiments show that Br2(g) is produced rapidly from deliquesced NaBr aerosols in the presence of OH radicals prod...

  19. Urban-rural interactions in a South Korean forest: uncertainties in isoprene-OH interactions limit understanding of ozone and secondary organic aerosols production

    NASA Astrophysics Data System (ADS)

    Kim, S.; Kim, S.-Y.; Lee, M.; Shim, H.; Wolfe, G. M.; Guenther, A. B.; He, A.; Hong, Y.; Han, J.

    2014-06-01

    Rapid urbanization and economic development in East Asia in past decades has led to photochemical air pollution problems such as excess photochemical ozone and aerosol formation. Asian megacities such as Seoul, Tokyo, Shanghai, Gangzhou, and Beijing are surrounded by densely forested areas and recent research has consistently demonstrated the importance of biogenic volatile organic compounds from vegetation in determining oxidation capacity in the suburban Asian megacity regions. Uncertainties in constraining tropospheric oxidation capacity, dominated by hydroxyl radical concentrations, undermine our ability to assess regional photochemical air pollution problems. We present an observational dataset of CO, NOx, SO2, ozone, HONO, and VOCs (anthropogenic and biogenic) from Taehwa Research Forest (TRF) near the Seoul Metropolitan Area (SMA) in early June 2012. The data show that TRF is influenced both by aged pollution and fresh BVOC emissions. With the dataset, we diagnose HOx (OH, HO2, and RO2) distributions calculated with the University of Washington Chemical Box Model (UWCM v 2.1). Uncertainty from unconstrained HONO sources and radical recycling processes highlighted in recent studies is examined using multiple model simulations with different model constraints. The results suggest that (1) different model simulation scenarios cause systematic differences in HOx distributions especially OH levels (up to 2.5 times) and (2) radical destruction (HO2+HO2 or HO2+RO2) could be more efficient than radical recycling (HO2+NO) especially in the afternoon. Implications of the uncertainties in radical chemistry are discussed with respect to ozone-VOC-NOx sensitivity and oxidation product formation rates. Overall, the VOC limited regime in ozone photochemistry is predicted but the degree of sensitivity can significantly vary depending on the model scenarios. The model results also suggest that RO2 levels are positively correlated with OVOCs production that is not routinely

  20. Optimal Aerosol Parameterization for Remote Sensing Retrievals

    NASA Technical Reports Server (NTRS)

    Newchurch, Michael J.

    2004-01-01

    We have developed a new algorithm for the retrieval of aerosol and gases from SAGE It1 solar transmission measurements. This algorithm improves upon the NASA operational algorithm in several key aspects, including solving the problem non-linearly and incorporating a new methodology for separating the contribution of aerosols and gases. In order to extract aerosol information we have built a huge database of aerosol models for both stratospheric and tropospheric aerosols, and polar stratospheric cloud particles. This set of models allows us to calculate a vast range of possible extinction spectra for aerosols. and from these, derive a set of eigenvectors which then provide the basis set used in our inversion algorithm. Our aerosol algorithm and retrievals are described in several articles (listed in References Section) published under this grant. In particular they allow us to analyze the spectral properties of aerosols and PSCs and ultimately derive their microphysical properties. We have found some considerable differences between our spectra and the ones derived from the SAGE III operational algorithm. These are interesting as they provide an independent check on the validity of published aerosol data and, in particular, on their associated uncertainties. In order to understand these differences, we are assembling independent aerosol data from other sources with which to make comparisons. We have carried out extensive comparisons of our ozone retrievals with both SAGE III and independent lidar, ozonesonde, and satellite measurements (Polyakov et al., 2004). These show very good agreement throughout the stratosphere and help to quantify differences which can be attributed to natural variation in ozone versus that produced by algorithmic differences. In the mid - upper stratosphere, agreement with independent data was generally within 5 - 20%. but in the lower stratosphere the differences were considerably larger. We believe that a large proportion of this

  1. Inter-comparison of MAX-DOAS Retrieved Vertical Profiles of Aerosol Extinction, SO2 and NO2 in the Alberta Oil Sands with LIDAR Data and GEM-MACH Air Quality Model.

    NASA Astrophysics Data System (ADS)

    Davis, Zoe; Friess, Udo; Strawbridge, Kevin; Whiteway, James; Aggarwal, Monika; Makar, Paul; Li, Shao-Meng; O'Brien, Jason; Baray, Sabour; Schnitzler, Elijah; Olfert, Jason S.; Osthoff, Hans D.; Lobo, Akshay; McLaren, Robert

    2016-04-01

    Understanding industrial emissions of trace gas pollutants in the Alberta oil sands is essential to maintaining air quality standards and informing public policy. Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of trace gases can improve knowledge of pollutant levels, vertical distribution and chemical transformation. During an intensive air measurement campaign to study emissions, transport, transformation and deposition of oil sands air pollutants from August to September of 2013, a MAX-DOAS instrument was deployed at a site north of Fort McMurray, Alberta to determine the vertical profiles of aerosol extinction, NO2 and SO2 through retrieval from the MAX-DOAS spectral measurements using an optimal estimation method. The large complement of data collected from multiple instruments deployed during this field campaign provides a unique opportunity to validate and characterize the performance of the MAX-DOAS vertical profile retrievals. Aerosol extinction profiles determined from two Light Detection and Ranging (LIDAR) instruments, one collocated and the other on a Twin Otter aircraft that flew over the site during the study, will be compared to the MAX-DOAS aerosol extinction profile retrievals. Vertical profiles of NO2 and SO2 retrieved from the MAX-DOAS measurements will be further compared with the composite vertical profiles measured from the flights of a second aircraft, the NRC-Convair 580, over the field site during the same measurement period. Finally, the MAX-DOAS retrieved tropospheric vertical column densities (VCDs) of SO2 and NO2 will be compared to the predicted VCDs from Environment and Climate Change Canada's Global Environmental Multi-scale - Modelling Air quality and Chemistry (GEM-MACH) air quality model over the grid cell containing the field site. Emission estimates of SO2 from the major oil mining facility Syncrude Mildred Lake using the MAX-DOAS VCD results, validated through the detailed characterization above

  2. Short- and long-term variability of spectral solar UV irradiance at Thessaloniki, Greece: effects of changes in aerosols, total ozone and clouds

    NASA Astrophysics Data System (ADS)

    Fountoulakis, Ilias; Bais, Alkiviadis F.; Fragkos, Konstantinos; Meleti, Charickleia; Tourpali, Kleareti; Zempila, Melina Maria

    2016-03-01

    In this study, we discuss the short- and the long-term variability of spectral UV irradiance at Thessaloniki, Greece, using a long, quality-controlled data set from two Brewer spectrophotometers. Long-term changes in spectral UV irradiance at 307.5, 324 and 350 nm for the period 1994-2014 are presented for different solar zenith angles and discussed in association with changes in total ozone column (TOC), aerosol optical depth (AOD) and cloudiness observed in the same period. Positive changes in annual mean anomalies of UV irradiance, ranging from 2 to 6 % per decade, have been detected both for clear- and all-sky conditions. The changes are generally greater for larger solar zenith angles and for shorter wavelengths. For clear-skies, these changes are, in most cases, statistically significant at the 95 % confidence limit. Decreases in the aerosol load and weakening of the attenuation by clouds lead to increases in UV irradiance in the summer, of 7-9 % per decade for 64° solar zenith angle. The increasing TOC in winter counteracts the effect of decreasing AOD for this particular season, leading to small, statistically insignificant, negative long-term changes in irradiance at 307.5 nm. Annual mean UV irradiance levels are increasing from 1994 to 2006 and remain relatively stable thereafter, possibly due to the combined changes in the amount and optical properties of aerosols. However, no statistically significant corresponding turning point has been detected in the long-term changes of AOD. The absence of signatures of changes in AOD in the short-term variability of irradiance in the UV-A may have been caused by changes in the single scattering albedo of aerosols, which may counteract the effects of changes in AOD on irradiance. The anti-correlation between the year-to-year variability of the irradiance at 307.5 nm and TOC is clear and becomes clearer as the AOD decreases.

  3. Absorption Angstrom Exponent in AERONET and related data as an indicator of aerosol composition

    NASA Astrophysics Data System (ADS)

    Russell, P. B.; Bergstrom, R. W.; Shinozuka, Y.; Clarke, A. D.; Decarlo, P. F.; Jimenez, J. L.; Livingston, J. M.; Redemann, J.; Dubovik, O.; Strawa, A.

    2010-02-01

    Recent results from diverse air, ground, and laboratory studies using both radiometric and in situ techniques show that the fractions of black carbon, organic matter, and mineral dust in atmospheric aerosols determine the wavelength dependence of absorption (often expressed as Absorption Angstrom Exponent, or AAE). Taken together, these results hold promise of improving information on aerosol composition from remote measurements. The main purpose of this paper is to show that AAE values for an Aerosol Robotic Network (AERONET) set of retrievals from Sun-sky measurements describing full aerosol vertical columns are also strongly correlated with aerosol composition or type. In particular, we find AAE values near 1 (the theoretical value for black carbon) for AERONET-measured aerosol columns dominated by urban-industrial aerosol, larger AAE values for biomass burning aerosols, and the largest AAE values for Sahara dust aerosols. These AERONET results are consistent with results from other, very different, techniques, including solar flux-aerosol optical depth (AOD) analyses and airborne in situ analyses examined in this paper, as well as many other previous results. Ambiguities in aerosol composition or mixtures thereof, resulting from intermediate AAE values, can be reduced via cluster analyses that supplement AAE with other variables, for example Extinction Angstrom Exponent (EAE), which is an indicator of particle size. Together with previous results, these results strengthen prospects for determining aerosol composition from space, for example using the Glory Aerosol Polarimetry Sensor (APS), which seeks to provide retrievals of multiwavelength single-scattering albedo (SSA) and aerosol optical depth (and therefore aerosol absorption optical depth (AAOD) and AAE), as well as shape and other aerosol properties. Multidimensional cluster analyses promise additional information content, for example by using the Ozone Monitoring Instrument (OMI) to add AAOD in the near

  4. Assessment of 10-Year Global Record of Aerosol Products from the OMI Near-UV Algorithm

    NASA Astrophysics Data System (ADS)

    Ahn, C.; Torres, O.; Jethva, H. T.

    2014-12-01

    Global observations of aerosol properties from space are critical for understanding climate change and air quality applications. The Ozone Monitoring Instrument (OMI) onboard the EOS-Aura satellite provides information on aerosol optical properties by making use of the large sensitivity to aerosol absorption and dark surface albedo in the UV spectral region. These unique features enable us to retrieve both aerosol extinction optical depth (AOD) and single scattering albedo (SSA) successfully from radiance measurements at 354 and 388 nm by the OMI near UV aerosol algorithm (OMAERUV). Recent improvements to algorithms in conjunction with the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Atmospheric Infrared Sounder (AIRS) carbon monoxide data also reduce uncertainties due to aerosol layer heights and types significantly in retrieved products. We present validation results of OMI AOD against space and time collocated Aerosol Robotic Network (AERONET) measured AOD values over multiple stations representing major aerosol episodes and regimes. We also compare the OMI SSA against the inversion made by AERONET as well as an independent network of ground-based radiometer called SKYNET in Japan, China, South-East Asia, India, and Europe. The outcome of the evaluation analysis indicates that in spite of the "row anomaly" problem, affecting the sensor since mid-2007, the long-term aerosol record shows remarkable sensor stability. The OMAERUV 10-year global aerosol record is publicly available at the NASA data service center web site (http://disc.sci.gsfc.nasa.gov/Aura/data-holdings/OMI/omaeruv_v003.shtml).

  5. Global volcanic aerosol properties derived from emissions, 1990-2014, using CESM1(WACCM)

    NASA Astrophysics Data System (ADS)

    Mills, Michael J.; Schmidt, Anja; Easter, Richard; Solomon, Susan; Kinnison, Douglas E.; Ghan, Steven J.; Neely, Ryan R.; Marsh, Daniel R.; Conley, Andrew; Bardeen, Charles G.; Gettelman, Andrew

    2016-03-01

    Accurate representation of global stratospheric aerosols from volcanic and nonvolcanic sulfur emissions is key to understanding the cooling effects and ozone losses that may be linked to volcanic activity. Attribution of climate variability to volcanic activity is of particular interest in relation to the post-2000 slowing in the rate of global average temperature increases. We have compiled a database of volcanic SO2 emissions and plume altitudes for eruptions from 1990 to 2014 and developed a new prognostic capability for simulating stratospheric sulfate aerosols in the Community Earth System Model. We used these combined with other nonvolcanic emissions of sulfur sources to reconstruct global aerosol properties from 1990 to 2014. Our calculations show remarkable agreement with ground-based lidar observations of stratospheric aerosol optical depth (SAOD) and with in situ measurements of stratospheric aerosol surface area density (SAD). These properties are key parameters in calculating the radiative and chemical effects of stratospheric aerosols. Our SAOD calculations represent a clear improvement over available satellite-based analyses, which generally ignore aerosol extinction below 15 km, a region that can contain the vast majority of stratospheric aerosol extinction at middle and high latitudes. Our SAD calculations greatly improve on that provided for the Chemistry-Climate Model Initiative, which misses about 60% of the SAD measured in situ on average during both volcanically active and volcanically quiescent periods.

  6. Design considerations for ozone and acid aerosol exposure and health investigations: the Fairview Lake summer camp - photochemical smog case study

    SciTech Connect

    Lioy, P.J.; Spektor, D.; Thurston, G.; Citak, K.; Lippmann, M.; Bock, N.; Speizer, F.E.; Hayes, C.

    1987-01-01

    The health effects associated with ozone and acidic particulate sulfate exposures to active children have been and are being addressed in field epidemiological studies at summer camps in rural areas of the Northeastern US. The rationale and study design for studies, which have been conducted in Pennsylvania and New Jersey, are developed and reviewed. As background, results are summarized for human clinical and epidemiological studies and animal studies. These provided the basis for selection of health outcomes measured results from chemical characterization and transport studies are reviewed to define the criteria used for selection of a site which is effected by high ozone and acid species during photochemical smog episodes. The integration of the study design is discussed in detail by reviewing its application to the 1984 - Fairview Lake Camp Study (July 8 to August 4). The features of the camp study are reviewed, including the study population, pulmonary function procedures and analyses, air pollution monitoring instrumentation, and the site characteristics. The pollution exposure data are presented, for ozone and acidic sulfates and examined for the range and distribution concentration. Further information is provided on the intensity and duration of episodes encountered over the course of the study. Episodes occurred which had ozone and acid sulfates, ozone alone, and acid sulfates alone. 56 references, 9 figures.

  7. Series cell light extinction monitor

    DOEpatents

    Novick, Vincent J.

    1990-01-01

    A method and apparatus for using the light extinction measurements from two or more light cells positioned along a gasflow chamber in which the gas volumetric rate is known to determine particle number concentration and mass concentration of an aerosol independent of extinction coefficient and to determine estimates for particle size and mass concentrations. The invention is independent of particle size. This invention has application to measurements made during a severe nuclear reactor fuel damage test.

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  9. Ozone and the stratosphere

    NASA Technical Reports Server (NTRS)

    Shimazaki, Tatsuo

    1987-01-01

    It is shown that the stratospheric ozone is effective in absorbing almost all radiation below 300 nm at heights below 300 km. The distribution of global ozone in the troposphere and the lower stratosphere, and the latitudinal variations of the total ozone column over four seasons are considered. The theory of the ozone layer production is discussed together with catalytic reactions for ozone loss and the mechanisms of ozone transport. Special attention is given to the anthropogenic perturbations, such as SST exhaust gases and freon gas from aerosol cans and refrigerators, that may cause an extensive destruction of the stratospheric ozone layer and thus have a profound impact on the world climate and on life.

  10. Rethinking Extinction.

    PubMed

    Dunsmoor, Joseph E; Niv, Yael; Daw, Nathaniel; Phelps, Elizabeth A

    2015-10-01

    Extinction serves as the leading theoretical framework and experimental model to describe how learned behaviors diminish through absence of anticipated reinforcement. In the past decade, extinction has moved beyond the realm of associative learning theory and behavioral experimentation in animals and has become a topic of considerable interest in the neuroscience of learning, memory, and emotion. Here, we review research and theories of extinction, both as a learning process and as a behavioral technique, and consider whether traditional understandings warrant a re-examination. We discuss the neurobiology, cognitive factors, and major computational theories, and revisit the predominant view that extinction results in new learning that interferes with expression of the original memory. Additionally, we reconsider the limitations of extinction as a technique to prevent the relapse of maladaptive behavior and discuss novel approaches, informed by contemporary theoretical advances, that augment traditional extinction methods to target and potentially alter maladaptive memories. PMID:26447572

  11. Absorption Angstrom Exponent in AERONET and related data as an indicator of aerosol composition

    NASA Astrophysics Data System (ADS)

    Russell, P. B.; Bergstrom, R. W.; Shinozuka, Y.; Clarke, A. D.; Decarlo, P. F.; Jimenez, J. L.; Livingston, J. M.; Redemann, J.; Holben, B.; Dubovik, O.; Strawa, A.

    2009-10-01

    Recent results from diverse air, ground, and laboratory studies using both radiometric and in situ techniques show that the fractions of black carbon, organic matter, and mineral dust in atmospheric aerosols determine the wavelength dependence of absorption (expressed as Absorption Angstrom Exponent, or AAE). Taken together, these results hold promise of improving information on aerosol composition from remote measurements. The purpose of this paper is to show that AAE values for Aerosol Robotic Network (AERONET) retrievals from Sun-sky measurements describing the full aerosol vertical column are also strongly correlated with aerosol composition or type. In particular, we find AAE values near 1 (the theoretical value for black carbon) for AERONET-measured aerosol columns dominated by urban-industrial aerosol, larger AAE values for biomass burning aerosols, and the largest AAE values for Sahara dust aerosols. Ambiguities in aerosol composition or mixtures thereof, resulting from intermediate AAE values, can be reduced via cluster analyses that supplement AAE with other variables, for example Extinction Angstrom Exponent (EAE), which is an indicator of particle size. Together with previous results, these results strengthen prospects for determining aerosol composition from space, for example using the Glory Aerosol Polarimetry Sensor (APS), which promises retrievals of multiwavelength single-scattering albedo (SSA) and aerosol optical depth (and therefore aerosol absorption optical depth (AAOD) and AAE), as well as shape and other aerosol properties. Cluster analyses promise additional information content, for example by using the Ozone Monitoring Instrument (OMI) to add AAOD in the near ultraviolet and CALIPSO aerosol layer heights to reduce height-absorption ambiguity.

  12. Polarimetric method of estimation of vertical aerosol distribution in application to observations of ozone and NO2

    NASA Technical Reports Server (NTRS)

    Elansky, Nikolay F.; Kadyshevich, Elena A.; Savastyuk, Vladimir V.

    1994-01-01

    The degree of polarization of skylight at the zenith during twilight depends on the aerosol content in the atmosphere. The long-term observations at the high-mountain research station 'Kislovodsk' (North Caucasus) have shown that the variation of the degree of polarization after the eruption of the El Chichon volcano can serve as the effective parameter characterizing the vertical aerosol stratification in the atmosphere. The results of the measurements are confirmed by the numerical calculations. The algorithm of the retrieval of the vertical aerosol distribution on the base of the measurements of the degree of polarization is proposed. This method can be applied for the increasing of the precision of O3, NO2, and other gas content measurements.

  13. Coordinated Airborne, Spaceborne, and Ground-Based Measurements of Massive, Thick Aerosol Layers During the Dry Season in Southern Africa

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Redemann, J.; Russell, P. B.; Hobbs, P. V.; Hlavka, D. L.; McGill, M. J.; Holben, B. N.; Welton, E. J.; Campbell, J.; Torres, O.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    During the dry-season airborne campaign of the Southern African Regional Science Initiative (SAFARI 2000), unique coordinated observations were made of massive, thick aerosol layers. These layers were often dominated by aerosols from biomass burning. We report on airborne Sunphotometer measurements of aerosol optical depth (lambda=354-1558 nm), columnar water vapor, and vertical profiles of aerosol extinction and water vapor density that were obtained aboard the University of Washington's Convair-580 research aircraft. We compare these with ground-based AERONET Sun/sky radiometer results, with ground based lidar data MPL-Net), and with measurements from a downward-pointing lidar aboard the high-flying NASA ER-2 aircraft. Finally, we show comparisons between aerosol optical depths from the Sunphotometer and those retrieved over land and over water using four spaceborne sensors (TOMS (Total Ozone Mapping Spectrometer), MODIS (Moderate Resolution Imaging Spectrometer), MISR (Multiangle Imaging Spectroradiometer) and ATSR-2 (Along Track Scanning Radiometer)).

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

    SciTech Connect

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

    1995-05-20

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

  15. Ozone Layer Observations

    NASA Technical Reports Server (NTRS)

    McPeters, Richard; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    The US National Aeronautics and Space Administration (NASA) has been monitoring the ozone layer from space using optical remote sensing techniques since 1970. With concern over catalytic destruction of ozone (mid-1970s) and the development of the Antarctic ozone hole (mid-1980s), long term ozone monitoring has become the primary focus of NASA's series of ozone measuring instruments. A series of TOMS (Total Ozone Mapping Spectrometer) and SBUV (Solar Backscatter Ultraviolet) instruments has produced a nearly continuous record of global ozone from 1979 to the present. These instruments infer ozone by measuring sunlight backscattered from the atmosphere in the ultraviolet through differential absorption. These measurements have documented a 15 Dobson Unit drop in global average ozone since 1980, and the declines in ozone in the antarctic each October have been far more dramatic. Instruments that measure the ozone vertical distribution, the SBUV and SAGE (Stratospheric Aerosol and Gas Experiment) instruments for example, show that the largest changes are occurring in the lower stratosphere and upper troposphere. The goal of ozone measurement in the next decades will be to document the predicted recovery of the ozone layer as CFC (chlorofluorocarbon) levels decline. This will require a continuation of global measurements of total column ozone on a global basis, but using data from successor instruments to TOMS. Hyperspectral instruments capable of measuring in the UV will be needed for this purpose. Establishing the relative roles of chemistry and dynamics will require instruments to measure ozone in the troposphere and in the stratosphere with good vertical resolution. Instruments that can measure other chemicals important to ozone formation and destruction will also be needed.

  16. Three air quality studies: Great Lakes ozone formation and nitrogen dry deposition; and Tucson aerosol chemical characterization

    NASA Astrophysics Data System (ADS)

    Foley, Theresa

    The Clean Air Act of 1970 was promulgated after thousands of lives were lost in four catastrophic air pollution events. It authorized the establishment of National Ambient Air Quality Standards or (NAAQS) for six pollutants that are harmful to human health and welfare: carbon monoxide, lead, nitrogen dioxide, particulate matter, ozone and sulfur dioxide. The Clean Air Act also led to the establishment of the United Stated Environmental Protection Agency (US EPA) to set and enforce regulations. The first paper in this dissertation studies ozone in the Lake Michigan region (Foley, T., Betterton, E.A., Jacko, R., Hillery, J., 2011. Lake Michigan air quality: The 1994-2003 LADCO Aircraft Project (LAP). Atmospheric Environment 45, 3192-3202.) The Chicago-Milwaukee-Gary metropolitan area has been unable to meet the ozone NAAQS since the Clean Air Act was implemented. The Lake Michigan Air Directors' Consortium (LADCO) hypothesized that land breezes transport ozone precursor compounds over the lake, where a large air/water temperature difference creates a shallow conduction layer, which is an efficient reaction chamber for ozone formation. In the afternoon, lake breezes and prevailing synoptic winds then transport ozone back over the land. To further evaluate this hypothesis, LADCO sponsored the 1994-2003 LADCO Aircraft Project (LAP) to measure the air quality over Lake Michigan and the surrounding areas. This study has found that the LAP data supports this hypothesis of ozone formation, which has strong implications for ozone control strategies in the Lake Michigan region. The second paper is this dissertation (Foley, T., Betterton, E.A., Wolf, A.M.A., 2012. Ambient PM10 and metal concentrations measured in the Sunnyside Unified School District, Tucson, Arizona. Journal of the Arizona-Nevada Academy of Science, 43, 67-76) evaluated the airborne concentrations of PM10 (particulate matter with an aerodynamic diameter of 10 microns or less) and eight metalloids and metals

  17. Lagrangian Aerosol and Ozone Precursor Forecasts Utilizing NASA Aura OMI NO2 and NOAA GOES-GASP AOD Observations

    EPA Science Inventory

    Over the past decade, the remote sensing of trace gases and aerosols from space has dramatically improved. The emergence and application of these measurements adds a new dimension to air quality Management and forecasting by enabling consistent observations of pollutants over l...

  18. Release 2 data products from the Ozone Mapping and Profiler Suite (OMPS) Limb Profiler

    NASA Technical Reports Server (NTRS)

    Xu, Q. Philippe; Bhartia, Pawan K.; Jaross, Glen R.; Deland, Matthew T.; Larsen, Jack C.; Fleig, Albert; Kahn, Daniel; Zhu, Tong; Chen, Zhong; Gorkavyi, Nick; Warner, Jeremy; Linda, Mike; Chen, Hong; Kowitt, Mark; Haken, Michael; Hall, Peter

    2014-01-01

    The OMPS Limb Profiler (LP) was launched on board the NASA Suomi National Polar-orbiting Partnership (SNPP) satellite in October 2011. OMPS-LP is a limb-scattering hyperspectral sensor that provides ozone profiling capability at 1.5 km vertical resolution from cloud top to 60 km altitude. The use of three parallel slits allows global coverage in approximately four days. We have recently completed a full reprocessing of all LP data products, designated as Release 2, that improves the accuracy and quality of these products. Level 1 gridded radiance (L1G) changes include intra-orbit and seasonal correction of variations in wavelength registration, revised static and intra-orbit tangent height adjustments, and simplified pixel selection from multiple images. Ozone profile retrieval changes include removal of the explicit aerosol correction, exclusion of channels contaminated by stratospheric OH emission, a revised instrument noise characterization, improved synthetic solar spectrum, improved pressure and temperature ancillary data, and a revised ozone climatology. Release 2 data products also include aerosol extinction coefficient profiles derived with the prelaunch retrieval algorithm. Our evaluation of OMPS LP Release 2 data quality is good. Zonal average ozone profile comparisons with Aura MLS data typically show good agreement, within 5-10% over the altitude range 20-50 km between 60 deg S and 60 deg N. The aerosol profiles agree well with concurrent satellite measurements such as CALIPSO and OSIRIS, and clearly detect exceptional events such as volcanic eruptions and the Chelyabinsk bolide in February 2013.

  19. Thermoluminescent aerosol analysis

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  20. Aerosol Extinction and Single Scattering Albedo Downwind of the Summer 2008 California Wildfires Measured With Photoacoustic Spectrometers and Sunphotometers From 355 nm to 1047 nm.

    NASA Astrophysics Data System (ADS)

    Arnott, W. P.; Gyawali, M. S.; Arnold, I. J.

    2008-12-01

    Hundreds of wildfires in Northern California were sparked by lightning during the summer of 2008, resulting in downwind smoke for much of June and July associated with the flaming and smoldering stages of the fires. These fires are consistent with a growing trend towards increasing biomass burning worldwide. Climate impacts from the smoke depend critically on the smoke amount and aerosol optical properties. We report comparison of aerosol optics measurements in Reno Nevada made during the very smoky summer month of July with the relatively clean, average month of August. Photoacoustic instruments equipped with integrating nephelometers were used to measure aerosol light scattering and absorption at wavelengths of 355 nm, 405 nm, 532 nm, 870 nm, and 1047 nm. Total aerosol optical depth was measured with a sun photometer operating at 430nm, 470nm, 530nm, 660nm, 870nm and 950nm. A spectrometer based sun photometer with an operating range from 390nm to 880 nm was also used for a few days as well. These measurements document the intensity of the smoke optical impacts downwind. They are processed further to reveal a strong variation of the aerosol light absorption on wavelength, indicating the presence of light absorbing organic material and perhaps wavelength dependent absorption caused by black carbon particles coated with organic and inorganic particulate matter. On the day with most smoke in Reno (July 10, 2008) Angstrom coefficients for absorption as high as 3.6 were found for wavelengths of 405 nm and 870 nm, with the corresponding single scattering albedo near 0.92 at 405 nm. Aerosol optical depths of 3.5 were found for 430 nm on July 10th from the sun photometer measurements. A roughly fourfold increase in aerosol optical quantities was observed between the months of July and August 2008, attesting to the large average effects of biomass aerosols from the California wildfires.

  1. The impact of U.S. continental outflow on ozone and aerosol distributions over the western Atlantic

    NASA Technical Reports Server (NTRS)

    Anderson, B. E.; Gregory, G. L.; Barrick, J. D. W.; Collins, J. E., Jr.; Sachse, G. W.; Bagwell, D.; Shipham, M. C.; Bradshaw, J. D.; Sandholm, S. T.

    1993-01-01

    Aircraft measurements of selected trace gas species, aerosols, and meteorological parameters were performed in the lower troposphere off the U.S. east coast during August and September 1989 as part of the NASA Global Tropospheric Experiment (GTE) Chemical Instrumentation Test and Evaluation (CITE 3) expedition. In this paper, we examine these data to assess the impact of continental outflow on western Atlantic O3 and small aerosol budgets. Results show that mixed layer (ML) O3 concentrations and small aerosol number densities (Np) were enhanced by factors of 3 and 6, respectively, within air masses of predominantly continental origin compared with clean maritime background air. These enhancements exhibited a marked altitude dependence, declining rapidly above the ML to the point where only slight to moderate differences in O3 and Np, respectively, were notable above 2.4 km. Within continentally influenced ML's, both O3 and Np were correlated with CO, exhibiting linear regression slopes averaging 0.4 ppbv (O3)/ppbv(CO) for O3 and 7.7 (particles/cc)/ppbv(CO) for Np and indicating a primarily anthropogenic origin for the observed enhancement of these species. Comparisons between profiles in continental and background maritime air masses suggest that photochemical production below 1.4-km altitude adds over 10% to western Atlantic tropospheric column O3 abundance in continental outflow regimes. For aerosols, eastward advection of low-level continental air contributes an average net flux of 2.8 metric tons of submicron (accumulation mode) particles per kilometer of shoreline per day to the western Atlantic troposphere.

  2. Agricultural fires in the southeastern U.S. during SEAC4RS: Emissions of trace gases and particles and evolution of ozone, reactive nitrogen, and organic aerosol

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoxi; Zhang, Y.; Huey, L. G.; Yokelson, R. J.; Wang, Y.; Jimenez, J. L.; Campuzano-Jost, P.; Beyersdorf, A. J.; Blake, D. R.; Choi, Y.; St. Clair, J. M.; Crounse, J. D.; Day, D. A.; Diskin, G. S.; Fried, A.; Hall, S. R.; Hanisco, T. F.; King, L. E.; Meinardi, S.; Mikoviny, T.; Palm, B. B.; Peischl, J.; Perring, A. E.; Pollack, I. B.; Ryerson, T. B.; Sachse, G.; Schwarz, J. P.; Simpson, I. J.; Tanner, D. J.; Thornhill, K. L.; Ullmann, K.; Weber, R. J.; Wennberg, P. O.; Wisthaler, A.; Wolfe, G. M.; Ziemba, L. D.

    2016-06-01

    Emissions from 15 agricultural fires in the southeastern U.S. were measured from the NASA DC-8 research aircraft during the summer 2013 Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. This study reports a detailed set of emission factors (EFs) for 25 trace gases and 6 fine particle species. The chemical evolution of the primary emissions in seven plumes was examined in detail for ~1.2 h. A Lagrangian plume cross-section model was used to simulate the evolution of ozone (O3), reactive nitrogen species, and organic aerosol (OA). Observed EFs are generally consistent with previous measurements of crop residue burning, but the fires studied here emitted high amounts of SO2 and fine particles, especially primary OA and chloride. Filter-based measurements of aerosol light absorption implied that brown carbon (BrC) was ubiquitous in the plumes. In aged plumes, rapid production of O3, peroxyacetyl nitrate (PAN), and nitrate was observed with ΔO3/ΔCO, ΔPAN/ΔNOy, and Δnitrate/ΔNOy reaching ~0.1, ~0.3, and ~0.3. For five selected cases, the model reasonably simulated O3 formation but underestimated PAN formation. No significant evolution of OA mass or BrC absorption was observed. However, a consistent increase in oxygen-to-carbon (O/C) ratios of OA indicated that OA oxidation in the agricultural fire plumes was much faster than in urban and forest fire plumes. Finally, total annual SO2, NOx, and CO emissions from agricultural fires in Arkansas, Louisiana, Mississippi, and Missouri were estimated (within a factor of ~2) to be equivalent to ~2% SO2 from coal combustion and ~1% NOx and ~9% CO from mobile sources.

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

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

    vapor, along with multi-wavelength aerosol extinction. Though in the visible portion of the spectrum the brightness of the Sun is one million times that of the full Moon, the SAGE III instrument is designed to cover this large dynamic range and also perform lunar occultations on a routine basis to augment the solar products. The standard lunar products were demonstrated during the SAGE III/M3M mission and include ozone, nitrogen dioxide & nitrogen trioxide. The operational flexibility of the SAGE III spectrometer accomplishes the main goal of producing ozone and aerosol extinction profiles, while allowing exploration of new possibilities for the occultation technique, such as night-time aerosol extinction profiles or other trace gases not measured by SAGE in the past.

  4. Investigating the links between ozone and organic aerosol chemistry in a biomass burning plume from a prescribed fire in California chaparral

    NASA Astrophysics Data System (ADS)

    Alvarado, M. J.; Lonsdale, C. R.; Yokelson, R. J.; Akagi, S. K.; Coe, H.; Craven, J. S.; Fischer, E. V.; McMeeking, G. R.; Seinfeld, J. H.; Soni, T.; Taylor, J. W.; Weise, D. R.; Wold, C. E.

    2014-12-01

    Within minutes after emission, rapid, complex photochemistry within a biomass burning smoke plume can cause large changes in the concentrations of ozone (O3) and organic aerosol (OA). Being able to understand and simulate this rapid chemical evolution under a wide variety of conditions is a critical part of forecasting the impact of these fires on air quality, atmospheric composition, and climate. Here we use version 2.1 of the Aerosol Simulation Program (ASP) to simulate the evolution of O3 and secondary organic aerosol (SOA) within a young biomass burning smoke plume from the Williams prescribed burn in chaparral, which was sampled over California in November 2009. We demonstrate the use of a method for simultaneously accounting for the impact of the unidentified semi-volatile to extremely low volatility organic compounds (here collectively called "SVOCs") on the formation of OA (using the Volatility Basis Set) and O3 (using the concept of mechanistic reactivity). We show that this method can successfully simulate the observations of O3, OA, PAN, NOx, and C2H4 to within measurement uncertainty using reasonable assumptions about the chemistry of the unidentified SVOCs. These assumptions were: (1) a~reaction rate constant with OH of ~10-11cm3s-1, (2) a significant fraction (~50%) of the RO2 + NO reaction resulted in fragmentation, rather than functionalization, of the parent SVOC, (3) ~1.1 molecules of O3 were formed for every molecule of SVOC that reacted, (4) ~60% of the OH that reacted with the unidentified SVOCs was regenerated as HO2, and (5) that ~50% of the NO that reacted with the SVOC peroxy radicals was lost, presumably to organic nitrate formation. Additional evidence for the fragmentation pathway is provided by the observed rate of formation of acetic acid, which is consistent with our assumed fragmentation rate. This method could provide a way for classifying different smoke plume observations in terms of the average chemistry of their SVOCs, and could

  5. Investigating the links between ozone and organic aerosol chemistry in a biomass burning plume from a prescribed fire in California chaparral

    NASA Astrophysics Data System (ADS)

    Alvarado, M. J.; Lonsdale, C. R.; Yokelson, R. J.; Akagi, S. K.; Coe, H.; Craven, J. S.; Fischer, E. V.; McMeeking, G. R.; Seinfeld, J. H.; Soni, T.; Taylor, J. W.; Weise, D. R.; Wold, C. E.

    2015-06-01

    Within minutes after emission, complex photochemistry in biomass burning smoke plumes can cause large changes in the concentrations of ozone (O3) and organic aerosol (OA). Being able to understand and simulate this rapid chemical evolution under a wide variety of conditions is a critical part of forecasting the impact of these fires on air quality, atmospheric composition, and climate. Here we use version 2.1 of the Aerosol Simulation Program (ASP) to simulate the evolution of O3 and secondary organic aerosol (SOA) within a young biomass burning smoke plume from the Williams prescribed fire in chaparral, which was sampled over California in November 2009. We demonstrate the use of a method for simultaneously accounting for the impact of the unidentified intermediate volatility, semi-volatile, and extremely low volatility organic compounds (here collectively called "SVOCs") on the formation of OA (using the Volatility Basis Set - VBS) and O3 (using the concept of mechanistic reactivity). We show that this method can successfully simulate the observations of O3, OA, NOx, ethylene (C2H4), and OH to within measurement uncertainty using reasonable assumptions about the average chemistry of the unidentified SVOCs. These assumptions were (1) a reaction rate constant with OH of ~ 10-11 cm3 s-1; (2) a significant fraction (up to ~ 50 %) of the RO2 + NO reaction resulted in fragmentation, rather than functionalization, of the parent SVOC; (3) ~ 1.1 molecules of O3 were formed for every molecule of SVOC that reacted; (4) ~ 60 % of the OH that reacted with the unidentified non-methane organic compounds (NMOC) was regenerated as HO2; and (5) that ~ 50 % of the NO that reacted with the SVOC peroxy radicals was lost, presumably to organic nitrate formation. Additional evidence for the fragmentation pathway is provided by the observed rate of formation of acetic acid (CH3COOH), which is consistent with our assumed fragmentation rate. However, the model overestimates peroxyacetyl

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  7. Global stratospheric aerosol distribution as measured by the OMPS/LP

    NASA Astrophysics Data System (ADS)

    Gorkavyi, N.; Rault, D. F.

    2012-12-01

    The Ozone Mapping and Profiler Suite (OMPS) was launched on board NPP/SUOMI in October 2011 to continue monitoring the global distribution of the Earth's middle atmosphere ozone and aerosol. The present paper will be concerned with the stratospheric aerosol product retrieved with the OMPS Limb Profiler (heritage: SOLSE/LORE, OSIRIS, SCIAMACHY, SAGE III). The retrieval algorithm will be described together with early results. The retrieved products will be compared with data of CALIPSO and OSIRIS. The vertical profile of aerosol extinction is retrieved over a range of wavelengths (typically 500-900nm), from which a moment of the size distribution (namely the Angstrom coefficient) is inferred. Results will be shown in the form of (a) curtain profiles of aerosol extinction over an altitude range covering the UTLS region ~ 10-35km (sampling rate of one measurement per km in vertical direction and one measurement per one degree latitude), (b) curtain profiles of Angstrom coefficients, (c) weekly global maps of vertical optical depth (the OMPS/LP revisit time is about 5 days). The global distribution of aerosols retrieved by the OMPS/LP in 2012 shows the presence of stable or slowly time-varying structures of stratospheric aerosol, with four distinct geographical features: - the Northern latitudes exhibit large aerosol loading distributed in 4 layers: large particles near tropopause, smaller particles around 15km, larger particles near 18km and a reservoir of small particles above 20km - the middle latitudes (~30 degrees N,S) are characterized by low aerosol loading - the equatorial region shows large aerosol loading with large particles near the tropopause - the southern region (< -30 degrees) exhibits low aerosol loading and small particles Particle size information inferred from retrieved values of the Angstrom coefficient could provide valuable information on aerosol dynamics. Early results show larger stratospheric particles over land masses than over the oceans

  8. Modeling comprehensive chemical composition of weathered oil following a marine spill to predict ozone and potential secondary aerosol formation and constrain transport pathways

    NASA Astrophysics Data System (ADS)

    Drozd, Greg T.; Worton, David R.; Aeppli, Christoph; Reddy, Christopher M.; Zhang, Haofei; Variano, Evan; Goldstein, Allen H.

    2015-11-01

    Releases of hydrocarbons from oil spills have large environmental impacts in both the ocean and atmosphere. Oil evaporation is not simply a mechanism of mass loss from the ocean, as it also causes production of atmospheric pollutants. Monitoring atmospheric emissions from oil spills must include a broad range of volatile organic compounds (VOC), including intermediate-volatile and semivolatile compounds (IVOC, SVOC), which cause secondary organic aerosol (SOA) and ozone production. The Deepwater Horizon (DWH) disaster in the northern Gulf of Mexico during Spring/Summer of 2010 presented a unique opportunity to observe SOA production due to an oil spill. To better understand these observations, we conducted measurements and modeled oil evaporation utilizing unprecedented comprehensive composition measurements, achieved by gas chromatography with vacuum ultraviolet time of flight mass spectrometry (GC-VUV-HR-ToFMS). All hydrocarbons with 10-30 carbons were classified by degree of branching, number of cyclic rings, aromaticity, and molecular weight; these hydrocarbons comprise ˜70% of total oil mass. Such detailed and comprehensive characterization of DWH oil allowed bottom-up estimates of oil evaporation kinetics. We developed an evaporative model, using solely our composition measurements and thermodynamic data, that is in excellent agreement with published mass evaporation rates and our wind-tunnel measurements. Using this model, we determine surface slick samples are composed of oil with a distribution of evaporative ages and identify and characterize probable subsurface transport of oil.

  9. Ozone Research with Advanced Cooperative Lidar Experiment (ORACLE) Implementation Study

    NASA Technical Reports Server (NTRS)

    Stadler, John H.; Browell, Edward V.; Ismail, Syed; Dudelzak, Alexander E.; Ball, Donald J.

    1998-01-01

    New technological advances have made possible new active remote sensing capabilities from space. Utilizing these technologies, the Ozone Research with Advanced Cooperative Lidar Experiment (ORACLE) will provide high spatial resolution measurements of ozone, clouds and aerosols in the stratosphere and lower troposphere. Simultaneous measurements of ozone, clouds and aerosols will assist in the understanding of global change, atmospheric chemistry and meteorology.

  10. Airborne Dial Remote Sensing of the Arctic Ozone Layer

    NASA Technical Reports Server (NTRS)

    Wirth, Martin; Renger, Wolfgang; Ehret, Gerhard

    1992-01-01

    A combined ozone and aerosol LIDAR was developed at the Institute of Physics of the Atmosphere at the DLR in Oberpfaffenhofen. It is an airborne version, that, based on the DIAL-principle, permits the recording of two-dimensional ozone profiles. This presentation will focus on the ozone-part; the aerosol subsection will be treated later.

  11. Light extinction in the atmosphere

    SciTech Connect

    Laulainen, N.

    1992-06-01

    Atmospheric aerosol particles originating from natural sources, such as volcanos and sulfur-bearing gas emissions from the oceans, and from human sources, such as sulfur emissions from fossil fuel combustion and biomass burning, strongly affect visual air quality and are suspected to significantly affect radiative climate forcing of the planet. During the daytime, aerosols obscure scenic vistas, while at night they diminish our ability to observe stellar objects. Scattering of light is the main means by which aerosols attenuate and redistribute light in the atmosphere and by which aerosols can alter and reduce visibility and potentially modify the energy balance of the planet. Trends and seasonal variability of atmospheric aerosol loading, such as column-integrated light extinction or optical depth, and how they may affect potential climate change have been difficult to quantify because there have been few observations made of important aerosol optical parameters, such as optical depth, over the globe and over time and often these are of uneven quality. To address questions related to possible climate change, there is a pressing need to acquire more high-quality aerosol optical depth data. Extensive deployment of improved solar radiometers over the next few years will provide higher-quality extinction data over a wider variety of locations worldwide. An often overlooked source of turbidity data, however, is available from astronomical observations, particularly stellar photoelectric photometry observations. With the exception of the Project ASTRA articles published almost 20 years ago, few of these data ever appear in the published literature. This paper will review the current status of atmosph