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Sample records for atmospheric emissions rich

  1. Emission Spectroscopy of Atmospheric-Pressure Ball Plasmoids: Higher Energy Reveals a Rich Chemistry

    NASA Astrophysics Data System (ADS)

    Dubowsky, Scott E.; Rose, Amber Nicole; Glumac, Nick; McCall, Benjamin J.

    2017-06-01

    Ball plasmoids (self-sustaining spherical plasmas) are a particularly unique example of a non-equilibrium air plasma. These plasmoids have lifetimes on the order of hundreds of milliseconds without an external power source, however, current models dictate that a ball plasmoid should recombine in a millisecond or less. Ball plasmoids are considered to be a laboratory analogue of natural ball lightning, a phenomenon that has eluded scientific explanation for centuries. We are searching for the underlying physicochemical mechanism(s) by which ball plasmoids and (by extension) ball lightning are stabilized using a variety of diagnostic techniques. This presentation will focus on optical emission spectroscopy (OES) of ball plasmoid discharges between 190-850 nm. The previous generation of OES measurements of this system showed emission from only a few atomic and molecular species, however, the energy available for the discharges in these experiments was limited by the size of the capacitor banks and voltages to which the capacitor banks were charged. We are capable of generating plasmoids at much higher energies, and as a result we are the first to report a very rich chemistry previously not observed in ball plasmoids. We have identified signals from species including NO A^{2}Σ^{+}→X^{2}Π, OH A^{2}Σ^{+}→X^{2}Π, NH A^{3}Π→X^{3}Σ^{-}, AlO A^{2}Π→X^{2}Σ^{+}, NH^{+} B^{2}Δ→X^{2}Π, W I, Al I, Cu I, and H_{α}, all of which have not yet been reported for this system. Analysis of the emission spectra and fitting procedures will be discussed, rotational temperatures of constituent species will be reported, and theories of ball plasmoid stabilization based upon these new results will be presented. Versteegh, A.; Behringer, K.; Fantz, U.; Fussman, G.; Jüttner, B.; Noack, S. Plas. Sour. Sci. Technol. 2008, 17(2), 024014 Stephan, K. D.; Dumas, S.; Komala-Noor, L.; McMinn, J. Plas. Sour. Sci. Technol. 2013, 22(2), 025018

  2. FIR Emission From Rich Clusters

    NASA Astrophysics Data System (ADS)

    Cox, Caroline

    1994-12-01

    Previous searches for far infrared (FIR) emission from dominant cluster galaxies using small, X-ray selected samples have found 20% to 50% of clusters to have significant FIR emission. In a new study, I have analyzed the 60microns and 100microns emission properties of cD galaxies in a complete sample of 163 Abell Clusters. For comparison, a control sample of 207 blank fields was analyzed to determine the distribution of spurious detections, which is greater than expected from Gaussian statistics. The contribution of Galactic cirrus at 60 microns and 100 microns to non-Gaussian noise is clearly demonstrated by the correspondence of a 98% confidence level to a signal to noise of 4 or 4.5 rather than to a signal to noise of 2 as expected from Gaussian statistics. After correcting for contaminated fields and spurious signals, I find that about 10% of cD galaxies in rich clusters are sources of FIR emission. Typical detected cDs have FIR luminosities of about 3 times 10(44) erg sec(-1) , which is comparable to the blue luminosities from these objects and an order of magnitude greater than the X-ray luminosities produced in the cores of clusters. Dust masses derived from the 60microns and 100 microns fluxes are ~ 10(7) M _sun. Because only about 10% of the clusters have high FIR luminosities, such strong emission is probably a transient state for an individual cluster. It has been suggested that this FIR emission is due to dust heated by electron collisions from the hot gas that dominates the intra-cluster medium. Study of the optical and X-ray properties of these clusters allows us to test models for the heating process of the dust, the origin of the dust, and its importance as a mechanism for cooling the hot gas. The central electron density and the temperature distribution for the hot gas are determined from analysis of ROSAT PSPC observations of four of these clusters. My program of UBVI imaging is designed to identify dust lanes and morphology that might indicate

  3. Atmospheric emission photometric imaging

    NASA Astrophysics Data System (ADS)

    Mende, S. B.

    1981-11-01

    A dual-channel video system mounted on a stabilized two-axis gimbal system (mounted on the pallet) with associated optics and data handling electronics described the low light flux observations are required for: (1) investigating ionospheric transport processes by observing Mg+ ions; (2) supporting magnetospheric electron bounce experiments; (3) measuring electron cross sections for selected atmospheric species; (4) detecting small particle contamination; and (5) studying natural auroras.

  4. Infrared Atmospheric Emission. I.

    DTIC Science & Technology

    1982-03-01

    contract. They are (i) "The 5g Levels of Atomic Nitrogen" AO)YA ii Edward S. Chang and Hajime Sakai J. Phys. B 14, L391 (1981) (ii) "Infrared Emission...At. Idol. Phys. 14 (1981) L391 -L395. printed in Great Bjritain LETTER TO THE EDITOR INC 5g levels of atomic nitrogent Edward S Chang and Hajime Sakai...81/120391 +05$01.30 C) 1981 The Institute of Physics L391 The U.S. Qovermnt is authoried to repoduce and sem tns report. Parmb@a- or ur Uther

  5. A hydrogen-rich early Earth atmosphere.

    PubMed

    Tian, Feng; Toon, Owen B; Pavlov, Alexander A; De Sterck, H

    2005-05-13

    We show that the escape of hydrogen from early Earth's atmosphere likely occurred at rates slower by two orders of magnitude than previously thought. The balance between slow hydrogen escape and volcanic outgassing could have maintained a hydrogen mixing ratio of more than 30%. The production of prebiotic organic compounds in such an atmosphere would have been more efficient than either exogenous delivery or synthesis in hydrothermal systems. The organic soup in the oceans and ponds on early Earth would have been a more favorable place for the origin of life than previously thought.

  6. Atmospheric transformation of diesel emissions.

    PubMed

    Zielinska, Barbara; Samy, Shar; McDonald, Jacob D; Seagrave, JeanClare

    2010-04-01

    The hypothesis of this study was that exposing diesel exhaust (DE*) to the atmosphere transforms its composition and toxicity. Our specific aims were (1) to characterize the gas- and particle-phase products of atmospheric transformations of DE under the influence of daylight, ozone (O3), hydroxyl (OH) radicals, and nitrate (NO3) radicals; and (2) to explore the biologic activity of DE before and after the transformations took place. The study was executed with the aid of the EUPHORE (European Photoreactor) outdoor simulation chamber facility in Valencia, Spain. EUPHORE is one of the largest and best-equipped facilities of its kind in the world, allowing investigation of atmospheric transformation processes under realistic ambient conditions (with dilutions in the range of 1:300). DE was generated on-site using a modern light-duty diesel engine and a dynamometer system equipped with a continuous emission-gas analyzer. The engine (a turbocharged, intercooled model with common-rail direct injection) was obtained from the Ford Motor Company. A first series of experiments was carried out in January 2005 (the winter 2005 campaign), a second in May 2005 (the summer 2005 campaign), and a third in May and June 2006 (the summer 2006 campaign). The diesel fuel that was used closely matched the one currently in use in most of the United States (containing 47 ppm sulfur and 15% aromatic compounds). Our experiments examined the effects on the composition of DE aged in the dark with added NO3 radicals and of DE aged in daylight with added OH radicals both with and without added volatile organic compounds (VOCs). In order to remove excess nitrogen oxides (NO(x)), a NO(x) denuder was devised and used to conduct experiments in realistic low-NO(x) conditions in both summer campaigns. A scanning mobility particle sizer was used to determine the particle size and the number and volume concentrations of particulate matter (PM) in the DE. O3, NO(x), and reactive nitrogen oxides (NO

  7. Convection in Condensible-rich Atmospheres

    NASA Astrophysics Data System (ADS)

    Ding, F.; Pierrehumbert, R. T.

    2016-05-01

    Condensible substances are nearly ubiquitous in planetary atmospheres. For the most familiar case—water vapor in Earth’s present climate—the condensible gas is dilute, in the sense that its concentration is everywhere small relative to the noncondensible background gases. A wide variety of important planetary climate problems involve nondilute condensible substances. These include planets near or undergoing a water vapor runaway and planets near the outer edge of the conventional habitable zone, for which CO2 is the condensible. Standard representations of convection in climate models rely on several approximations appropriate only to the dilute limit, while nondilute convection differs in fundamental ways from dilute convection. In this paper, a simple parameterization of convection valid in the nondilute as well as dilute limits is derived and used to discuss the basic character of nondilute convection. The energy conservation properties of the scheme are discussed in detail and are verified in radiative-convective simulations. As a further illustration of the behavior of the scheme, results for a runaway greenhouse atmosphere for both steady instellation and seasonally varying instellation corresponding to a highly eccentric orbit are presented. The latter case illustrates that the high thermal inertia associated with latent heat in nondilute atmospheres can damp out the effects of even extreme seasonal forcing.

  8. Virtual atmospheric mercury emission network in China.

    PubMed

    Liang, Sai; Zhang, Chao; Wang, Yafei; Xu, Ming; Liu, Weidong

    2014-01-01

    Top-down analysis of virtual atmospheric mercury emission networks can direct efficient demand-side policy making on mercury reductions. Taking China-the world's top atmospheric mercury emitter-as a case, we identify key contributors to China's atmospheric mercury emissions from both the producer and the consumer perspectives. China totally discharged 794.9 tonnes of atmospheric mercury emissions in 2007. China's production-side control policies should mainly focus on key direct mercury emitters such as Liaoning, Hebei, Shandong, Shanxi, Henan, Hunan, Guizhou, Yunnan, and Inner Mongolia provinces and sectors producing metals, nonmetallic mineral products, and electricity and heat power, while demand-side policies should mainly focus on key underlying drivers of mercury emissions such as Shandong, Jiangsu, Zhejiang, and Guangdong provinces and sectors of construction activities and equipment manufacturing. China's interregional embodied atmospheric mercury flows are generally moving from the inland to the east coast. Beijing-Tianjin (with 4.8 tonnes of net mercury inflows) and South Coast (with 3.3 tonnes of net mercury inflows) are two largest net-inflow regions, while North (with 5.3 tonnes of net mercury outflows) is the largest net-outflow region. We also identify primary supply chains contributing to China's virtual atmospheric mercury emission network, which can be used to trace the transfers of production-side and demand-side policy effects.

  9. Research on atmospheric volcanic emissions - An overview

    NASA Technical Reports Server (NTRS)

    Friend, J. P.; Bandy, A. R.; Moyers, J. L.; Zoller, W. H.; Stoiber, R. E.; Torres, A. L.; Rose, W. I., Jr.; Mccormick, M. P.; Woods, D. C.

    1982-01-01

    Atmospheric abundances and the geochemical cycle of certain volatile compounds and elements may be largely influenced or entirely controlled by magmatic sources. However, better estimates of the magnitude and variability of volcanic emissions are required if the importance of this natural source of atmospheric constituents and the resulting effect on atmospheric chemistry are to be elucidated. The project 'Research on Atmospheric Volcanic Emissions' (RAVE) is concerned with the improvement of knowledge of both geological and chemical phenomena attending these emissions by means of comprehensive instrumentation on board a research aircraft making simultaneous measurements of plume constituents. A description is presented of the equipment and the procedures used in the RAVE field study of Mt. St. Helens' plume. An overview of the results is also provided.

  10. Anthropogenic atmospheric emissions of cadmium in China

    NASA Astrophysics Data System (ADS)

    Shao, Xiao; Cheng, Hongguang; Li, Qian; Lin, Chunye

    2013-11-01

    In this study, we estimated atmospheric Cd emissions from anthropogenic sources in China from 1990 to 2010 on the basis of consumption or output data and emission factors. China emitted approximately 2186 t Cd to the atmosphere in 2010, with approximately 77% and 14% of the emissions arising from non-ferrous metal smelting and coal combustion, respectively. Temporal changes in the total Cd emissions were characterized by two periods of increase (1990-2000 and 2001-2010) and a short period of decrease (2000-2001) due to application of energy-saving and cleaner production technologies. Overall, atmospheric Cd emissions increased from 474 t in 1990 to 2186 t in 2010 due to rapid economic growth, whereas energy-saving and cleaner production technologies have been in use since 2000. Spatial distribution of the atmospheric Cd emissions was dominated primarily by non-ferrous metal smelting and coal combustion. Emissions are high in Hunan and Yunnan Provinces because of high production non-ferrous metal smelting and in Shandong Province because of high coal consumption and moderate non-ferrous metal production.

  11. Comment on "A hydrogen-rich early Earth atmosphere".

    PubMed

    Catling, David C

    2006-01-06

    Tian et al. (Reports, 13 May 2005, p. 1014) proposed a hydrogen-rich early atmosphere with slow hydrogen escape from a cold thermosphere. However, their model neglects the ultraviolet absorption of all gases other than H2. The model also neglects Earth's magnetic field, which affects the temperature and density of ions and promotes nonthermal escape of neutral hydrogen.

  12. Attributing Atmospheric Methane to Anthropogenic Emission Sources.

    PubMed

    Allen, David

    2016-07-19

    Methane is a greenhouse gas, and increases in atmospheric methane concentration over the past 250 years have driven increased radiative forcing of the atmosphere. Increases in atmospheric methane concentration since 1750 account for approximately 17% of increases in radiative forcing of the atmosphere, and that percentage increases by approximately a factor of 2 if the effects of the greenhouse gases produced by the atmospheric reactions of methane are included in the assessment. Because of the role of methane emissions in radiative forcing of the atmosphere, the identification and quantification of sources of methane emissions is receiving increased scientific attention. Methane emission sources include biogenic, geogenic, and anthropogenic sources; the largest anthropogenic sources are natural gas and petroleum systems, enteric fermentation (livestock), landfills, coal mining, and manure management. While these source categories are well-known, there is significant uncertainty in the relative magnitudes of methane emissions from the various source categories. Further, the overall magnitude of methane emissions from all anthropogenic sources is actively debated, with estimates based on source sampling extrapolated to regional or national scale ("bottom-up analyses") differing from estimates that infer emissions based on ambient data ("top-down analyses") by 50% or more. To address the important problem of attribution of methane to specific sources, a variety of new analytical methods are being employed, including high time resolution and highly sensitive measurements of methane, methane isotopes, and other chemical species frequently associated with methane emissions, such as ethane. This Account describes the use of some of these emerging measurements, in both top-down and bottom-up methane emission studies. In addition, this Account describes how data from these new analytical methods can be used in conjunction with chemical mass balance (CMB) methods for source

  13. Geologic emissions of methane to the atmosphere.

    PubMed

    Etiope, Giuseppe; Klusman, Ronald W

    2002-12-01

    The atmospheric methane budget is commonly defined assuming that major sources derive from the biosphere (wetlands, rice paddies, animals, termites) and that fossil, radiocarbon-free CH4 emission is due to and mediated by anthropogenic activity (natural gas production and distribution, and coal mining). However, the amount of radiocarbon-free CH4 in the atmosphere, estimated at approximately 20% of atmospheric CH4, is higher than the estimates from statistical data of CH4 emission from fossil fuel related anthropogenic sources. This work documents that significant amounts of "old" methane, produced within the Earth crust, can be released naturally into the atmosphere through gas permeable faults and fractured rocks. Major geologic emissions of methane are related to hydrocarbon production in sedimentary basins (biogenic and thermogenic methane) and, subordinately, to inorganic reactions (Fischer-Tropsch type) in geothermal systems. Geologic CH4 emissions include diffuse fluxes over wide areas, or microseepage, on the order of 10(0)-10(2) mg m(-2) day(-1), and localised flows and gas vents, on the order of 10(2) t y(-1), both on land and on the seafloor. Mud volcanoes producing flows of up to 10(3) t y(-1) represent the largest visible expression of geologic methane emission. Several studies have indicated that methanotrophic consumption in soil may be insufficient to consume all leaking geologic CH4 and positive fluxes into the atmosphere can take place in dry or seasonally cold environments. Unsaturated soils have generally been considered a major sink for atmospheric methane, and never a continuous, intermittent, or localised source to the atmosphere. Although geologic CH4 sources need to be quantified more accurately, a preliminary global estimate indicates that there are likely more than enough sources to provide the amount of methane required to account for the suspected missing source of fossil CH4.

  14. Orographic Disturbances of Upper Atmosphere Emissions

    NASA Technical Reports Server (NTRS)

    Shefov, N. N.; Pertsev, N. N.

    1984-01-01

    There are some increases of the temperature of the hydroxyl emission (delta T approximately 20 K, z approximately 90 km) and of the intensity of the 63000 oxygen emission (delta I/I approximately 20 per cent, z approximately 250 km) for the lee of the mountains at distances about 150 km in the case of the latitudinal direction of the wind (U approximately 10 m/s) at the 3000 m level. Airflow motions over mountains may be one of the possible processes of generation of wave disturbances penetrating into the upper atmospheres (HINES, 1974; LINDZEN, 1971). The purpose here is to study the penetration of orographic disturbances into upper atmosphere. Airplane measurements of emission variations of hydroxyl and atomic oxygen 6300 A near the Northern Ural mountains were made. Several nocturnal flights were carried out in March, 1980 and January to February, 1981 at heights about 3000 m along 64 deg northern latitude in the Ural region. Spectrographs SP-48 with electronic image converters registration for OH ((9,4) and (5,1) bands - 7700 to 8100 A) and OI (6300 A) emissions were used. The zenith region was observed, and exposure time was 2 minutes. This corresponds to averaging of the emission intensities along the airplane trace over a distance of 10 km. Simultaneous measurements of atmospheric temperature variations at the flight altitude were made.

  15. Water Loss from Terrestrial Planets with CO2-rich Atmospheres

    NASA Astrophysics Data System (ADS)

    Wordsworth, R. D.; Pierrehumbert, R. T.

    2013-12-01

    Water photolysis and hydrogen loss from the upper atmospheres of terrestrial planets is of fundamental importance to climate evolution but remains poorly understood in general. Here we present a range of calculations we performed to study the dependence of water loss rates from terrestrial planets on a range of atmospheric and external parameters. We show that CO2 can only cause significant water loss by increasing surface temperatures over a narrow range of conditions, with cooling of the middle and upper atmosphere acting as a bottleneck on escape in other circumstances. Around G-stars, efficient loss only occurs on planets with intermediate CO2 atmospheric partial pressures (0.1-1 bar) that receive a net flux close to the critical runaway greenhouse limit. Because G-star total luminosity increases with time but X-ray and ultraviolet/ultravoilet luminosity decreases, this places strong limits on water loss for planets like Earth. In contrast, for a CO2-rich early Venus, diffusion limits on water loss are only important if clouds caused strong cooling, implying that scenarios where the planet never had surface liquid water are indeed plausible. Around M-stars, water loss is primarily a function of orbital distance, with planets that absorb less flux than ~270 W m-2 (global mean) unlikely to lose more than one Earth ocean of H2O over their lifetimes unless they lose all their atmospheric N2/CO2 early on. Because of the variability of H2O delivery during accretion, our results suggest that many "Earth-like" exoplanets in the habitable zone may have ocean-covered surfaces, stable CO2/H2O-rich atmospheres, and high mean surface temperatures.

  16. Atmospheric Ammonia Emissions from a Dairy

    NASA Astrophysics Data System (ADS)

    Rumburg, B. P.; Filipy, J. M.; Bays, J.; Mount, G. H.; Yonge, D.; Lamb, B. K.; Johnson, K.; Kincaid, R.

    2002-12-01

    Gaseous ammonia (NH3) emissions at high concentrations can damage human and animal respiratory systems. NH3 environmental impacts include aerosol formation, altering atmospheric chemistry, terrestrial and aquatic eutrophication, soil acidification and global warming. Preindustrial NH3 emissions are estimated to be 21 Tg yr-1 while current emissions are estimated to be 47 Tg yr-1 with most of the increase coming from domestic animals (Galloway et al., 1995). There is a lack of detailed emission data from the United States and there are many problems with applying emissions estimates from Europe due to the difference in farming practices between the two regions. Feed and manure management practices can have a large impact on emissions. We are studying NH3 emissions at the WSU dairy located near Pullman, WA to provide a detailed emission inventory of the various sources at the dairy. The dairy has approximately 170 milking cows housed in open air barns and the waste from the milking cows is stored in liquid slurry lagoons until it is applied to grass fields in the late summer. NH3 is measured using a short-path spectroscopic absorption near 200 nm with a sensitivity of a few ppbv and a time resolution of a few seconds. The open air short-path method is advantageous because it is self calibrating and avoids inlet wall adherence which is a major problem for most NH3 measurement techniques. As part of the detailed emission inventory, NH3 fluxes were determined from the milking stalls, main slurry lagoon and the application of slurry to the fields with a large sprinkler using a SF6 tracer technique and a dense point Gaussian plume model. NH3 emission fluxes from various parts of the dairy will be presented.

  17. Beta-Delayed Neutron Emission in Neutron-Rich Nuclei

    NASA Astrophysics Data System (ADS)

    Marketin, Tomislav; Sieverding, André; Wu, Meng-Ru; Paar, Nils; Martínez-Pinedo, Gabriel

    β-delayed neutron emission is the process of emission of one or more neutrons, after β-decay, from the excited daughter nucleus. The probabilities of emission are an important physical quantity in a variety of nuclear physics applications, from the simulations of heavy element nucleosynthesis to control of reactor power levels and nuclear waste management. However, it is relatively difficult to measure and much less data is available than for β-decay, particularly for nuclei that are expected to take part in the r-process. In this work we will present a calculation of β-decay half-lives and β-delayed neutron emission probabilities in neutron-rich nuclei using the transition strength obtained with a microscopic model combined with a statistical calculation of level densities. We explore the effect of altered emission probabilities, with respect to the simple calculation, on the r-process.

  18. The Stability of Hydrogen-Rich Atmospheres of Earth-Like Planets

    NASA Technical Reports Server (NTRS)

    Zahnle, Kevin

    2016-01-01

    Understanding hydrogen escape is essential to understanding the limits to habitability, both for liquid water where the Sun is bright, but also to assess the true potential of H2 as a greenhouse gas where the Sun is faint. Hydrogen-rich primary atmospheres of Earth-like planets can result either from gravitational capture of solar nebular gases (with helium), or from impact shock processing of a wide variety of volatile-rich planetesimals (typically accompanied by H2O, CO2, and under the right circumstances, CH4). Most studies of hydrogen escape from planets focus on determining how fast the hydrogen escapes. In general this requires solving hydro- dynamic equations that take into account the acceleration of hydrogen through a critical transonic point and an energy budget that should include radiative heating and cooling, thermal conduction, the work done in lifting the hydrogen against gravity, and the residual heat carried by the hydrogen as it leaves. But for planets from which hydrogen escape is modest or insignificant, the atmosphere can be approximated as hydrostatic, which is much simpler, and for which a relatively full-featured treatment of radiative cooling by embedded molecules, atoms, and ions such as CO2 and H3+ is straightforward. Previous work has overlooked the fact that the H2 molecule is extremely efficient at exciting non-LTE CO2 15 micron emission, and thus that radiative cooling can be markedly more efficient when H2 is abundant. We map out the region of phase space in which terrestrial planets keep hydrogen-rich atmospheres, which is what we actually want to know for habitability. We will use this framework to reassess Tian et al's hypothesis that H2-rich atmospheres may have been rather long-lived on Earth itself. Finally, we will address the empirical observation that rocky planets with thin or negligible atmospheres are rarely or never bigger than 1.6 Earth radii.

  19. Radiometrically accurate FTS for atmospheric emission observations

    NASA Technical Reports Server (NTRS)

    Revercomb, H. E.; Smith, W. L.; Stromovsky, L. A.; Knuteson, R. O.; Buijs, H.

    1989-01-01

    The calibration and operational performance of an FTIR-based airborne high-resolution interferometer sounder (HIS) for use in broadband measurements of atmospheric emission at 3.8-16.6 microns are described. The radiometric and wavelength calibration procedures in the laboratory involved the use of reference black bodies at 300 and 245 K and the known wavelength of the HIS HeNe laser (corrected for FOV effects), respectively. The atmospheric verification program included downlooking observations from the NASA U2/ER2 aircraft (where resolving power of 1800-3800 was demonstrated) and uplooking observations from the ground; good agreement with data from balloon-borne radiosondes is obtained, with absolute temperature uncertainties of less than 0.5 K and reproducibilities of 0.1-0.2 K over most of the measurement domain.

  20. Atmospheric process evaluation of mobile source emissions

    SciTech Connect

    1995-07-01

    During the past two decades there has been a considerable effort in the US to develop and introduce an alternative to the use of gasoline and conventional diesel fuel for transportation. The primary motives for this effort have been twofold: energy security and improvement in air quality, most notably ozone, or smog. The anticipated improvement in air quality is associated with a decrease in the atmospheric reactivity, and sometimes a decrease in the mass emission rate, of the organic gas and NO{sub x} emissions from alternative fuels when compared to conventional transportation fuels. Quantification of these air quality impacts is a prerequisite to decisions on adopting alternative fuels. The purpose of this report is to present a critical review of the procedures and data base used to assess the impact on ambient air quality of mobile source emissions from alternative and conventional transportation fuels and to make recommendations as to how this process can be improved. Alternative transportation fuels are defined as methanol, ethanol, CNG, LPG, and reformulated gasoline. Most of the discussion centers on light-duty AFVs operating on these fuels. Other advanced transportation technologies and fuels such as hydrogen, electric vehicles, and fuel cells, will not be discussed. However, the issues raised herein can also be applied to these technologies and other classes of vehicles, such as heavy-duty diesels (HDDs). An evaluation of the overall impact of AFVs on society requires consideration of a number of complex issues. It involves the development of new vehicle technology associated with engines, fuel systems, and emission control technology; the implementation of the necessary fuel infrastructure; and an appropriate understanding of the economic, health, safety, and environmental impacts associated with the use of these fuels. This report addresses the steps necessary to properly evaluate the impact of AFVs on ozone air quality.

  1. Atmospheric science: marine aerosols and iodine emissions.

    PubMed

    McFiggans, Gordon

    2005-02-10

    O'Dowd et al. describe the formation of marine aerosols from biogenic iodine and the growth of these aerosols into cloud-condensation nuclei (CCN). Based on chamber and modelling results, the authors suggest that biogenic organic iodine compounds emitted from macroalgae may be responsible for coastal particle bursts and that production of these compounds in the open ocean could increase CCN there too. It has since been shown that coastal particles are more likely to be produced from the photooxidation of molecular iodine. Moreover, I contend that open-ocean particle production and cloud enhancement do not result from emissions of organic iodine at atmospheric levels. For iodine particles to affect cloud properties over the remote ocean, an additional source of iodine is necessary as organic precursors cannot be responsible.

  2. Quantifying aluminum and semiconductor industry perfluorocarbon emissions from atmospheric measurements

    NASA Astrophysics Data System (ADS)

    Kim, Jooil; Fraser, Paul J.; Li, Shanlan; Mühle, Jens; Ganesan, Anita L.; Krummel, Paul B.; Steele, L. Paul; Park, Sunyoung; Kim, Seung-Kyu; Park, Mi-Kyung; Arnold, Tim; Harth, Christina M.; Salameh, Peter K.; Prinn, Ronald G.; Weiss, Ray F.; Kim, Kyung-Ryul

    2014-07-01

    The potent anthropogenic perfluorocarbon greenhouse gases tetrafluoromethane (CF4) and hexafluoroethane (C2F6) are emitted to the atmosphere mainly by the aluminum and semiconductor industries. Global emissions of these perfluorocarbons (PFCs) calculated from atmospheric measurements are significantly greater than expected from reported national and industry-based emission inventories. In this study, in situ measurements of the two PFCs in the Advanced Global Atmospheric Gases Experiment network are used to show that their emission ratio varies according to the relative regional presence of these two industries, providing an industry-specific emission "signature" to apportion the observed emissions. Our results suggest that underestimated emissions from the global semiconductor industry during 1990-2010, as well as from China's aluminum industry after 2002, account for the observed differences between emissions based on atmospheric measurements and on inventories. These differences are significant despite the large uncertainties in emissions based on the methodologies used by these industries.

  3. Global simulation of UV atmospheric emissions on Mars

    NASA Astrophysics Data System (ADS)

    González-Galindo, Francisco; Ángel López-Valverde, Miguel; Forget, Francois; Montmessin, Franck; Stiepen, Arnaud

    2016-04-01

    Mars UV atmospheric emissions such as the CO2+ UV doublet, the CO Cameron bands (both in the dayside) and the NO bands (in the nightside) are systematically observed by SPICAM on board Mars Express and IUVS on board MAVEN. The study of these atmospheric emissions allows the determination of the temperature and density in the Martian upper atmosphere, and helps to constrain the thermospheric circulation. While different models have been developed to study these atmospheric emissions, most of them are one dimensional and make a number of assumptions concerning the underlying neutral atmosphere and ionosphere. Within the H2020 project UPWARDS we aim at including models of these atmospheric emissions into a state-of-the-art Global Climate Model for the Martian atmosphere, the LMD-MGCM. This will allow for a self-consistent description of these atmospheric emissions and for the characterizion of their different variability sources. Comparisons with observations will allow to retrieve information about the temperature and density in the Martian upper atmosphere. Here we will present the first results concerning the simulation of these UV emissions and the first comparisons with observations. Acknowledgemnt: This work is supported by the European Union's Horizon 2020 Programme under grant agreement UPWARDS-633127

  4. Atmospheric and environmental impacts of volcanic ash particle emissions

    NASA Astrophysics Data System (ADS)

    Durant, Adam

    2010-05-01

    Globally, at any one time, there may be 20 volcanoes erupting that collectively emit a constant flux of gases and aerosol, including silicate particles (tephra), to the atmosphere which influences processes including cloud microphysics, heterogeneous chemistry and radiative balance. The nature and impact of atmospheric volcanic particle fluxes depend on total mass erupted, emission rate, emission source location, physical and chemical properties of the particles, and the location and residence time of the particles in the atmosphere. Removal of ash particles from the atmosphere through sedimentation is strongly influenced by particle aggregation through hydrometeor formation, and convective instabilities such as mammatus. I will address the following questions: What are the atmospheric impacts of volcanic ash emissions? What controls the residence time of volcanic particles in the atmosphere? What affects particle accumulation at the surface? And what are the human and environmental impacts of ash fallout?

  5. Water emission from the chemically rich outflow L1157

    NASA Astrophysics Data System (ADS)

    Vasta, M.; Codella, C.; Lorenzani, A.; Santangelo, G.; Nisini, B.; Giannini, T.; Tafalla, M.; Liseau, R.; van Dishoeck, E. F.; Kristensen, L.

    2012-01-01

    Context. In the framework of the Herschel-WISH key program, several ortho-H2O and para-H2O emission lines, in the frequency range from 500 to 1700 GHz, were observed with the HIFI instrument in two bow-shock regions (B2 and R) of the L1157 cloud, which hosts what is considered to be the prototypical chemically-rich outflow. Aims: Our primary aim is to analyse water emission lines as a diagnostic of the physical conditions in the blue (B2) and red-shifted (R) lobes to compare the excitation conditions. Methods: For this purpose, we ran the non-LTE RADEX model for a plane-parallel geometry to constrain the physical parameters (Tkin, NH2O and nH2) of the water emission lines detected. Results: A total of 5 ortho- and para-H216O plus one o-H218O transitions were observed in B2 and R with a wide range of excitation energies (27 K ≤ Eu ≤ 215 K). The H2O spectra, observed in the two shocked regions, show that the H2O profiles differ markedly in the two regions. In particular, at the bow-shock R, we observed broad (~30 km s-1 with respect to the ambient velocity) red-shifted wings where lines at different excitation peak at different red-shifted velocities. The B2 spectra are associated with a narrower velocity range (~6 km s-1), peaking at the systemic velocity. The excitation analysis suggests, for B2, low values of column density NH2O ≤ 5 × 1013 cm-2, a density range of 105 ≤ nH2 ≤ 107 cm-3, and warm temperatures (≥300 K). The presence of the broad red-shifted wings and multiple peaks in the spectra of the R region, prompted the modelling of two components. High velocities are associated with relatively low temperatures (~100 K), NH2O ≃ 5 × 1012-5 × 1013 cm-2 and densities nH2 ≃ 106-108 cm-3. Lower velocities are associated with higher excitation conditions with Tkin ≥ 300 K, very dense gas (nH2 ~ 108 cm-3) and low column density (NH2O < 5 × 1013 cm-2). Conclusions: The overall analysis suggests that the emission in B2 comes from an extended (

  6. Modeling the effects of atmospheric emissions on groundwater composition

    SciTech Connect

    Brown, Theresa Jean

    1994-01-01

    A composite model of atmospheric, unsaturated and groundwater transport is developed to evaluate the processes determining the distribution of atmospherically derived contaminants in groundwater systems and to test the sensitivity of simulated contaminant concentrations to input parameters and model linkages. One application is to screen specific atmospheric emissions for their potential in determining groundwater age. Temporal changes in atmospheric emissions could provide a recognizable pattern in the groundwater system. The model also provides a way for quantifying the significance of uncertainties in the tracer source term and transport parameters on the contaminant distribution in the groundwater system, an essential step in using the distribution of contaminants from local, point source atmospheric emissions to examine conceptual models of groundwater flow and transport.

  7. Emission Database for Global Atmospheric Research (EDGAR).

    ERIC Educational Resources Information Center

    Olivier, J. G. J.; And Others

    1994-01-01

    Presents the objective and methodology chosen for the construction of a global emissions source database called EDGAR and the structural design of the database system. The database estimates on a regional and grid basis, 1990 annual emissions of greenhouse gases, and of ozone depleting compounds from all known sources. (LZ)

  8. Emission Database for Global Atmospheric Research (EDGAR).

    ERIC Educational Resources Information Center

    Olivier, J. G. J.; And Others

    1994-01-01

    Presents the objective and methodology chosen for the construction of a global emissions source database called EDGAR and the structural design of the database system. The database estimates on a regional and grid basis, 1990 annual emissions of greenhouse gases, and of ozone depleting compounds from all known sources. (LZ)

  9. Cluster emissions with ? daughter from neutron-rich nuclei

    NASA Astrophysics Data System (ADS)

    Kumar, Satish; Batra, J. S.; Gupta, Raj K.

    1996-02-01

    Cluster emissions from neutron-rich 0954-3899/22/2/006/img2, and 0954-3899/22/2/006/img3 nuclei are studied within the preformed cluster model of Malik and Gupta. Q-value estimates of the decays selected on the basis of shell effects in binding energies and their relative preformation probabilities show that these nuclei are stable (Q<0) against 0954-3899/22/2/006/img4 and 0954-3899/22/2/006/img5 decays and all the metastable (Q>0) decays are of non-alpha-like heavy clusters. The most probable decays (minimum half-life times) are the ones with a doubly magic 0954-3899/22/2/006/img6 nucleus as the daughter nucleus, arising due to the WKB penetrability. Compared to the presently measurable alpha-like cluster decays of the corresponding neutron-deficient parents into a 0954-3899/22/2/006/img7 daughter nucleus, these decays are suppressed by many orders of magnitude.

  10. The travel-related carbon dioxide emissions of atmospheric researchers

    NASA Astrophysics Data System (ADS)

    Stohl, A.

    2008-04-01

    Most atmospheric scientists agree that greenhouse gas emissions have already caused significant changes to the global climate system and that these changes will accelerate in the near future. At the same time, atmospheric scientists who - like other scientists - rely on international collaboration and information exchange travel a lot and, thereby, cause substantial emissions of carbon dioxide (CO2). In this paper, the CO2 emissions of the employees working at an atmospheric research institute (the Norwegian Institute for Air Research, NILU) caused by all types of business travel (conference visits, workshops, field campaigns, instrument maintainance, etc.) were calculated for the years 2005-2007. It is estimated that more than 90% of the emissions were caused by air travel, 3% by ground travel and 5% by hotel usage. The travel-related annual emissions were between 1.9 and 2.4 t CO2 per employee or between 3.9 and 5.5 t CO2 per scientist. For comparison, the total annual per capita CO2 emissions are 4.5 t worldwide, 1.2 t for India, 3.8 t for China, 5.9 t for Sweden and 19.1 t for Norway. The travel-related CO2 emissions of a NILU scientist, occurring in 24 days of a year on average, exceed the global average annual per capita emission. Norway's per-capita CO2 emissions are among the highest in the world, mostly because of the emissions from the oil industry. If the emissions per NILU scientist derived in this paper are taken as representative for the average Norwegian researcher, travel by Norwegian scientists would nevertheless account for a substantial 0.2% of Norway's total CO2 emissions. Since most of the travel-related emissions are due to air travel, water vapor emissions, ozone production and contrail formation further increase the relative importance of NILU's travel in terms of radiative forcing.

  11. The travel-related carbon dioxide emissions of atmospheric researchers

    NASA Astrophysics Data System (ADS)

    Stohl, A.

    2008-11-01

    Most atmospheric scientists agree that greenhouse gas emissions have already caused significant changes to the global climate system and that these changes will accelerate in the near future. At the same time, atmospheric scientists who like other scientists rely on international collaboration and information exchange travel a lot and, thereby, cause substantial emissions of CO2. In this paper, the CO2 emissions of the employees working at an atmospheric research institute (the Norwegian Institute for Air Research, NILU) caused by all types of business travel (conference visits, workshops, field campaigns, instrument maintainance, etc.) were calculated for the years 2005 2007. It is estimated that more than 90% of the emissions were caused by air travel, 3% by ground travel and 5% by hotel usage. The travel-related annual emissions were between 1.9 and 2.4 t CO2 per employee or between 3.9 and 5.5 t CO2 per scientist. For comparison, the total annual per capita CO2 emissions are 4.5 t worldwide, 1.2 t for India, 3.8 t for China, 5.9 t for Sweden and 19.1 t for Norway. The travel-related CO2 emissions of a NILU scientist, occurring in 24 days of a year on average, exceed the global average annual per capita emission. Norway's per-capita CO2 emissions are among the highest in the world, mostly because of the emissions from the oil industry. If the emissions per NILU scientist derived in this paper are taken as representative for the average Norwegian researcher, travel by Norwegian scientists would nevertheless account for a substantial 0.2% of Norway's total CO2 emissions. Since most of the travel-related emissions are due to air travel, water vapor emissions, ozone production and contrail formation further increase the relative importance of NILU's travel in terms of radiative forcing.

  12. Optical emission spectroscopy of atmospheric pressure microwave plasmas

    SciTech Connect

    Jia Haijun; Fujiwara, Hiroyuki; Kondo, Michio; Kuraseko, Hiroshi

    2008-09-01

    The optical emission behaviors of Ar, He, and Ar+He plasmas generated in air using an atmospheric pressure microwave plasma source have been studied employing optical emission spectroscopy (OES). Emissions from various source gas species and air were observed. The variations in the intensities and intensity ratios of specific emissions as functions of the microwave power and gas flow rate were analyzed to investigate the relationship between the emission behavior and the plasma properties. We find that dependence of the emission behavior on the input microwave power is mainly determined by variations in electron density and electron temperature in the plasmas. On the other hand, under different gas flow rate conditions, changes in the density of the source gas atoms also significantly affect the emissions. Interestingly, when plasma is generated using an Ar+He mixture, emissions from excited He atoms disappear while a strong H{sub {alpha}} signal appears. The physics behind these behaviors is discussed in detail.

  13. NOAA's Van-Based Mobile Atmospheric Emissions Measurement Laboratory

    NASA Astrophysics Data System (ADS)

    Dube, W. P.; Peischl, J.; Neuman, J. A.; Eilerman, S. J.; Holloway, M.; Roberts, O.; Aikin, K. C.; Ryerson, T. B.

    2015-12-01

    The Chemical Science Division (CSD) mobile atmospheric emissions measurement laboratory is the second and latest of two mobile measurement vans outfitted for atmospheric sampling by the NOAA Earth System Research Laboratory. In this presentation we will describe the modifications made to this vehicle to provide a versatile and relatively inexpensive instrument platform including: the 2 kW 120 volt instrument power system; battery back-up system; data acquisition system; real-time display; meteorological, directional, and position sensor package; and the typical atmospheric emissions instrument package. The van conversion uses commercially available, off-the-shelf components from the marine and RV industries, thus keeping the costs quite modest.

  14. Nonflammable organic-base paint for oxygen-rich atmospheres

    NASA Technical Reports Server (NTRS)

    Harwell, R. J.; Key, C. F.; Krupnick, A. C.

    1971-01-01

    New paint formulations, which combine aqueous latex paints with inorganic pigments and additives, produce coatings that are self-extinguishing in pure oxygen at pressures up to twice the partial pressure of atmospheric oxygen. A paint formulation in percent by weight is given and the properties of resultant coatings are discussed.

  15. Atmospheric verification of anthropogenic CO2 emission trends

    NASA Astrophysics Data System (ADS)

    Francey, Roger J.; Trudinger, Cathy M.; van der Schoot, Marcel; Law, Rachel M.; Krummel, Paul B.; Langenfelds, Ray L.; Paul Steele, L.; Allison, Colin E.; Stavert, Ann R.; Andres, Robert J.; Rödenbeck, Christian

    2013-05-01

    International efforts to limit global warming and ocean acidification aim to slow the growth of atmospheric CO2, guided primarily by national and industry estimates of production and consumption of fossil fuels. Atmospheric verification of emissions is vital but present global inversion methods are inadequate for this purpose. We demonstrate a clear response in atmospheric CO2 coinciding with a sharp 2010 increase in Asian emissions but show persisting slowing mean CO2 growth from 2002/03. Growth and inter-hemispheric concentration difference during the onset and recovery of the Global Financial Crisis support a previous speculation that the reported 2000-2008 emissions surge is an artefact, most simply explained by a cumulative underestimation (~ 9PgC) of 1994-2007 emissions; in this case, post-2000 emissions would track mid-range of Intergovernmental Panel on Climate Change emission scenarios. An alternative explanation requires changes in the northern terrestrial land sink that offset anthropogenic emission changes. We suggest atmospheric methods to help resolve this ambiguity.

  16. Reconciling reported and unreported HFC emissions with atmospheric observations.

    PubMed

    Lunt, Mark F; Rigby, Matthew; Ganesan, Anita L; Manning, Alistair J; Prinn, Ronald G; O'Doherty, Simon; Mühle, Jens; Harth, Christina M; Salameh, Peter K; Arnold, Tim; Weiss, Ray F; Saito, Takuya; Yokouchi, Yoko; Krummel, Paul B; Steele, L Paul; Fraser, Paul J; Li, Shanlan; Park, Sunyoung; Reimann, Stefan; Vollmer, Martin K; Lunder, Chris; Hermansen, Ove; Schmidbauer, Norbert; Maione, Michela; Arduini, Jgor; Young, Dickon; Simmonds, Peter G

    2015-05-12

    We infer global and regional emissions of five of the most abundant hydrofluorocarbons (HFCs) using atmospheric measurements from the Advanced Global Atmospheric Gases Experiment and the National Institute for Environmental Studies, Japan, networks. We find that the total CO2-equivalent emissions of the five HFCs from countries that are required to provide detailed, annual reports to the United Nations Framework Convention on Climate Change (UNFCCC) increased from 198 (175-221) Tg-CO2-eq ⋅ y(-1) in 2007 to 275 (246-304) Tg-CO2-eq ⋅ y(-1) in 2012. These global warming potential-weighted aggregated emissions agree well with those reported to the UNFCCC throughout this period and indicate that the gap between reported emissions and global HFC emissions derived from atmospheric trends is almost entirely due to emissions from nonreporting countries. However, our measurement-based estimates of individual HFC species suggest that emissions, from reporting countries, of the most abundant HFC, HFC-134a, were only 79% (63-95%) of the UNFCCC inventory total, while other HFC emissions were significantly greater than the reported values. These results suggest that there are inaccuracies in the reporting methods for individual HFCs, which appear to cancel when aggregated together.

  17. Reconciling reported and unreported HFC emissions with atmospheric observations

    PubMed Central

    Lunt, Mark F.; Rigby, Matthew; Ganesan, Anita L.; Manning, Alistair J.; Prinn, Ronald G.; O’Doherty, Simon; Mühle, Jens; Harth, Christina M.; Salameh, Peter K.; Arnold, Tim; Weiss, Ray F.; Saito, Takuya; Yokouchi, Yoko; Krummel, Paul B.; Steele, L. Paul; Fraser, Paul J.; Li, Shanlan; Park, Sunyoung; Reimann, Stefan; Vollmer, Martin K.; Lunder, Chris; Hermansen, Ove; Schmidbauer, Norbert; Maione, Michela; Arduini, Jgor; Young, Dickon; Simmonds, Peter G.

    2015-01-01

    We infer global and regional emissions of five of the most abundant hydrofluorocarbons (HFCs) using atmospheric measurements from the Advanced Global Atmospheric Gases Experiment and the National Institute for Environmental Studies, Japan, networks. We find that the total CO2-equivalent emissions of the five HFCs from countries that are required to provide detailed, annual reports to the United Nations Framework Convention on Climate Change (UNFCCC) increased from 198 (175–221) Tg-CO2-eq⋅y–1 in 2007 to 275 (246–304) Tg-CO2-eq⋅y–1 in 2012. These global warming potential-weighted aggregated emissions agree well with those reported to the UNFCCC throughout this period and indicate that the gap between reported emissions and global HFC emissions derived from atmospheric trends is almost entirely due to emissions from nonreporting countries. However, our measurement-based estimates of individual HFC species suggest that emissions, from reporting countries, of the most abundant HFC, HFC-134a, were only 79% (63–95%) of the UNFCCC inventory total, while other HFC emissions were significantly greater than the reported values. These results suggest that there are inaccuracies in the reporting methods for individual HFCs, which appear to cancel when aggregated together. PMID:25918401

  18. Development of Atmospheric Infrared Emission Models

    DTIC Science & Technology

    2007-11-02

    spectral radiance may be calculated for an arbitrary line -of-sight (LOS) passing through up to seven profiles . Interpolation is used to... Spectral Line with the Voigt Profile ," J. Quant. Spectrosc. Radiat. Transfer, 14, 319 (1974). 34. "U. S. Standard Atmosphere 1976," National Oceanic... Spectral Radiance Model 7 2.4.1 Calculation for a Single Line 7 2.4.2 Illustrative Calculations 9 2.5 Data Comparisons 11 3. DEVELOPMENT OF

  19. Ammonia in the atmosphere: a review on emission sources, atmospheric chemistry and deposition on terrestrial bodies.

    PubMed

    Behera, Sailesh N; Sharma, Mukesh; Aneja, Viney P; Balasubramanian, Rajasekhar

    2013-11-01

    Gaseous ammonia (NH3) is the most abundant alkaline gas in the atmosphere. In addition, it is a major component of total reactive nitrogen. The largest source of NH3 emissions is agriculture, including animal husbandry and NH3-based fertilizer applications. Other sources of NH3 include industrial processes, vehicular emissions and volatilization from soils and oceans. Recent studies have indicated that NH3 emissions have been increasing over the last few decades on a global scale. This is a concern because NH3 plays a significant role in the formation of atmospheric particulate matter, visibility degradation and atmospheric deposition of nitrogen to sensitive ecosystems. Thus, the increase in NH3 emissions negatively influences environmental and public health as well as climate change. For these reasons, it is important to have a clear understanding of the sources, deposition and atmospheric behaviour of NH3. Over the last two decades, a number of research papers have addressed pertinent issues related to NH3 emissions into the atmosphere at global, regional and local scales. This review article integrates the knowledge available on atmospheric NH3 from the literature in a systematic manner, describes the environmental implications of unabated NH3 emissions and provides a scientific basis for developing effective control strategies for NH3.

  20. The influence of atmospheric pressure on landfill methane emissions.

    PubMed

    Czepiel, P M; Shorter, J H; Mosher, B; Allwine, E; McManus, J B; Harriss, R C; Kolb, C E; Lamb, B K

    2003-01-01

    Landfills are the largest source of anthropogenic methane (CH4) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH4 emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH4 emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5-8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m3 CH4 min(-1). A simple regression model of our results was used to calculate an annual emission rate of 8.4 x 10(6) m3 CH4 year(-1). These data, along with CH4 oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH4 generation at this landfill. A reported gas collection rate of 7.1 x 10(6) m3 CH4 year(-1) and an estimated annual rate of CH4 oxidation by cover soils of 1.2 x 10(6) m3 CH4 year(-1) resulted in a calculated annual CH4 generation rate of 16.7 x 10(6) m3 CH4 year(-1). These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential.

  1. Reactive trace gas emissions from stressed plants: a poorly characterized major source of atmospheric volatiles

    NASA Astrophysics Data System (ADS)

    Niinemets, Ülo

    2017-04-01

    Vegetation constitutes the greatest source of reactive volatile organic compounds in the atmosphere. The current emission estimates primarily rely on constitutive emissions that are present only in some plant species. However, all plant species can be induced to emit reactive volatiles by different abiotic and biotic stresses, but the stress-dependent emissions have been largely neglected in emission measurements and models. This presentation provides an overview of systematic screening of stress-dependent volatile emissions from a broad range of structurally and physiologically divergent plant species from temperate to tropical ecosystems. Ozone, heat, drought and wounding stress were the abiotic stresses considered in the screening, while biotic stress included herbivory, chemical elicitors simulating herbivory and fungal infections. The data suggest that any moderate to severe stress leads to significant emissions of a rich blend of volatiles, including methanol, green leaf volatiles (the lipoxygenase pathway volatiles, dominated by C6 aldehydes, alcohols and derivatives), different mono- and sesquiterpenes and benzenoids. The release of volatiles occurs in stress severity-dependent manner, although the emission responses are often non-linear with more severe stresses resulting in disproportionately greater emissions. Stress volatile release is induced in both non-constitutive and constitutive volatile emitters, whereas the rate of constitutive volatile emissions in constitutive emitters is often reduced under environmental and biotic stresses. Given that plants in natural conditions often experience stress, this analysis suggests that global volatile emissions have been significantly underestimated. Furthermore, in globally changing hotter climates, the frequency and severity of both abiotic and biotic stresses is expected to increase. Thus, the stress-induced volatile emissions are predicted to play a dominant role in plant-atmosphere interactions in near

  2. Tropical epiphytes in a CO 2-rich atmosphere

    NASA Astrophysics Data System (ADS)

    Monteiro, José Alberto Fernandez; Zotz, Gerhard; Körner, Christian

    2009-01-01

    We tested the effect on epiphyte growth of a doubling of pre-industrial CO 2 concentration (280 vs. 560 ppm) combined with two light (three fold) and two nutrition (ten fold) treatments under close to natural humid conditions in daylight growth cabinets over 6 months. Across co-treatments and six species, elevated CO 2 increased relative growth rates by only 6% ( p = 0.03). Although the three C3 species, on average, grew 60% faster than the three CAM species, the two groups did not significantly differ in their CO 2 response. The two Orchidaceae, Bulbophyllum (CAM) and Oncidium (C3) showed no CO 2 response, and three out of four Bromeliaceae showed a positive one: Aechmea (CAM, +32% p = 0.08), Catopsis (C3, +11% p = 0.01) and Vriesea (C3, +4% p = 0.02). In contrast, the representative of the species-rich genus Tillandsia (CAM), which grew very well under experimental conditions, showed no stimulation. On average, high light increased growth by 21% and high nutrients by 10%. Interactions between CO 2, light and nutrient treatments (low vs. high) were inconsistent across species. CO 2 responsive taxa such as Catopsis, could accelerate tropical forest dynamics and increase branch breakage, but overall, the responses to doubling CO 2 of these epiphytes was relatively small and the responses were taxa specific.

  3. Atmospheric particulate emissions from dry abrasive blasting using coal slag

    SciTech Connect

    Bhaskar Kura; Kalpalatha Kambham; Sivaramakrishnan Sangameswaran; Sandhya Potana

    2006-08-15

    Coal slag is one of the widely used abrasives in dry abrasive blasting. Atmospheric emissions from this process include particulate matter (PM) and heavy metals, such as chromium, lead, manganese, nickel. Quantities and characteristics of PM emissions depend on abrasive characteristics and process parameters. Emission factors are key inputs to estimate emissions. Experiments were conducted to study the effect of blast pressure, abrasive feed rate, and initial surface contamination on total PM (TPM) emission factors for coal slag. Rusted and painted mild steel surfaces were used as base plates. Blasting was carried out in an enclosed chamber, and PM was collected from an exhaust duct using U.S. Environment Protection Agency source sampling methods for stationary sources. Results showed that there is significant effect of blast pressure, feed rate, and surface contamination on TPM emissions. Mathematical equations were developed to estimate emission factors in terms of mass of emissions per unit mass of abrasive used, as well as mass of emissions per unit of surface area cleaned. These equations will help industries in estimating PM emissions based on blast pressure and abrasive feed rate. In addition, emissions can be reduced by choosing optimum operating conditions. 40 refs., 5 figs., 2 tabs.

  4. Atmospheric particulate emissions from dry abrasive blasting using coal slag.

    PubMed

    Kura, Bhaskar; Kambham, Kalpalatha; Sangameswaran, Sivaramakrishnan; Potana, Sandhya

    2006-08-01

    Coal slag is one of the widely used abrasives in dry abrasive blasting. Atmospheric emissions from this process include particulate matter (PM) and heavy metals, such as chromium, lead, manganese, nickel. Quantities and characteristics of PM emissions depend on abrasive characteristics and process parameters. Emission factors are key inputs to estimate emissions. Experiments were conducted to study the effect of blast pressure, abrasive feed rate, and initial surface contamination on total PM (TPM) emission factors for coal slag. Rusted and painted mild steel surfaces were used as base plates. Blasting was carried out in an enclosed chamber, and PM was collected from an exhaust duct using U.S. Environment Protection Agency source sampling methods for stationary sources. Results showed that there is significant effect of blast pressure, feed rate, and surface contamination on TPM emissions. Mathematical equations were developed to estimate emission factors in terms of mass of emissions per unit mass of abrasive used, as well as mass of emissions per unit of surface area cleaned. These equations will help industries in estimating PM emissions based on blast pressure and abrasive feed rate. In addition, emissions can be reduced by choosing optimum operating conditions.

  5. Coupled land-atmosphere modeling of methane emissions with WRF

    NASA Astrophysics Data System (ADS)

    Taylor, D.

    2013-12-01

    This project aims to couple a soil model for methane transport to an atmospheric model to predict methane emissions and dispersion. Methane is a potent greenhouse gas, 20 times as efficient at trapping heat in the atmosphere as the most prevalent greenhouse gas, carbon dioxide. It has been estimated that 60% of methane emissions in the earth's atmosphere come from anthropogenic sources, 17% of which comes from landfills, making landfills the third largest contributor of human-generated methane. Due to high costs and non-ideal weather conditions, field measurements of methane concentration at landfills are difficult and infrequent, so estimates of annual emissions from landfills are not very accurate. We plan to create a coupled land-atmosphere model that takes production and oxidation of methane into account when calculating methane emissions. This model will give a better understanding of how much methane is emitted annually from a given landfill and assist with monitoring efforts. It will also demonstrate the magnitude of diurnal and seasonal variations in methane emissions, which may identify errors in yearly methane emissions estimates made by extrapolating from a small number of field measurements. As a first step, an existing land-surface model, Noah, is modified to compute the transport of oxygen and methane along a 1-D soil column. Surface emissions are calculated using a gradient flux method with a boundary layer conductance that depends on the wind speed. These modifications to the land-surface model will be added to the Weather Research and Forecasting model to predict atmospheric dispersion of methane emitted by landfills. Comparisons to observations are made at two different landfill sites to validate the coupled model.

  6. Nitrogen trifluoride global emissions estimated from updated atmospheric measurements

    PubMed Central

    Arnold, Tim; Harth, Christina M.; Mühle, Jens; Manning, Alistair J.; Salameh, Peter K.; Kim, Jooil; Ivy, Diane J.; Steele, L. Paul; Petrenko, Vasilii V.; Severinghaus, Jeffrey P.; Baggenstos, Daniel; Weiss, Ray F.

    2013-01-01

    Nitrogen trifluoride (NF3) has potential to make a growing contribution to the Earth’s radiative budget; however, our understanding of its atmospheric burden and emission rates has been limited. Based on a revision of our previous calibration and using an expanded set of atmospheric measurements together with an atmospheric model and inverse method, we estimate that the global emissions of NF3 in 2011 were 1.18 ± 0.21 Gg⋅y−1, or ∼20 Tg CO2-eq⋅y−1 (carbon dioxide equivalent emissions based on a 100-y global warming potential of 16,600 for NF3). The 2011 global mean tropospheric dry air mole fraction was 0.86 ± 0.04 parts per trillion, resulting from an average emissions growth rate of 0.09 Gg⋅y−2 over the prior decade. In terms of CO2 equivalents, current NF3 emissions represent between 17% and 36% of the emissions of other long-lived fluorinated compounds from electronics manufacture. We also estimate that the emissions benefit of using NF3 over hexafluoroethane (C2F6) in electronics manufacture is significant—emissions of between 53 and 220 Tg CO2-eq⋅y−1 were avoided during 2011. Despite these savings, total NF3 emissions, currently ∼10% of production, are still significantly larger than expected assuming global implementation of ideal industrial practices. As such, there is a continuing need for improvements in NF3 emissions reduction strategies to keep pace with its increasing use and to slow its rising contribution to anthropogenic climate forcing. PMID:23341630

  7. Atmospheric Sulfur Hexafluoride: Measurements and Emission Estimates from 1970 - 2008

    NASA Astrophysics Data System (ADS)

    Rigby, M. L.; Prinn, R. G.; Muhle, J.; Miller, B. R.; Dlugokencky, E. J.; Krummel, P. B.; Steele, L. P.; Fraser, P. J.; Leist, M.; Weiss, R. F.; Harth, C. M.; O'Doherty, S. J.; Greally, B. R.; Simmonds, P. G.; Derek, N.; Vollmer, M. K.; Kim, J.; Kim, K.; Porter, L. W.

    2009-12-01

    We present an air history of atmospheric sulfur hexafluoride (SF6) from the early 1970s through 2008. During this period, concentrations of this extremely potent and long-lived greenhouse gas have increased by more than an order of magnitude, and its growth has accelerated in recent years. In this study, historical concentrations are determined from archived air samples measured on the Advanced Global Atmospheric Gases Experiment (AGAGE) ‘Medusa’ gas chromatography/mass spectrometry system. These data are combined with modern high-frequency measurements from the AGAGE and National Oceanic and Atmospheric Administration (NOAA) in situ networks and ˜weekly samples from the NOAA flask network, to produce a unique time series with increasing global coverage spanning almost four decades. Using the three-dimensional chemical transport Model for Ozone and Related Tracers (MOZART v4.5) and a discrete Kalman filter, we derive estimates of the annual emission strength of SF6 on hemispheric scales from 1970 - 2004 and on continental scales from 2004 - 2008. Our emission estimates are compared to the recently compiled Emissions Database for Global Atmospheric Research (EDGAR v4), and emissions reported under the United Nations Framework Convention on Climate Change (UNFCCC). The cause of the recent growth rate increase is also investigated, indicating that the origin of the required emissions rise is likely to be South-East Asia.

  8. Thermal emission spectroscopy of the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Kunde, V. G.; Brasunas, J. C.; Conrath, B. J.; Herman, J. R.; Maguire, W. C.; Massie, S. T.; Abbas, Mian M.

    1990-01-01

    The general objective of this research is to obtain, via remote sensing, simultaneous measurements of the vertical distributions of stratospheric temperature, ozone, and trace constituents that participate in the catalytic destruction of ozone (NO(sub y): NO, NO2, NO3, HNO3, ClONO2, N2O5, HNO4; Cl(sub x): HOCl), and the source gases for the catalytic cycles (H2O, CH4, N2O, CF2Cl2, CFCl3, CCl4, CH3Cl, CHF2Cl, etc.). Data are collected during a complete diurnal cycle in order to test our present understanding of ozone chemistry and its associate catalytic cycles. The instrumentation employed is an emission-mode, balloon-borne, liquid-nitrogen-cooled Michelson interferometer-spectrometer (SIRIS), covering the mid-infrared range with a spectral resolution of 0.020 cm(exp -1). Cryogenic cooling combined with the use of extrinsic silicon photoconductor detectors allows the detection of weak emission features of stratospheric gaseous species. Vertical distributions of these species are inferred from scans of the thermal emission of the limb in a sequence of elevation angles. The fourth SIRIS balloon flight was carried out from Palestine, Texas on September 15-16, 1986 with 9 hours of nighttime data (40 km). High quality data with spectral resolution 0.022 cm(exp -1), were obtained for numerous limb sequences. Fifteen stratospheric species have been identified to date from this flight: five species from the NO(sub y) family (HNO3, NO2, NO, ClONO2, N2O5), plus CO2, O3, H2O, N2O, CH4, CCl3F, CCl2F2, CHF2Cl, CF4, and CCl4. The nighttime values of N2O5, ClONO2, and total odd nitrogen have been measured for the first time, and compared to model results. Analysis of the diurnal variation of N2O5 within the 1984 and 1986 data sets, and of the 1984 ClONO2 measurements, were presented in the literature. The demonstrated ability of SIRIS to measure all the major NO(sub y) species, and therefore to determine the partitioning of the nitrogen family over a continuous diurnal cycle, is

  9. Atmospheric Inverse Estimates of Methane Emissions from Central California

    SciTech Connect

    Zhao, Chuanfeng; Andrews, Arlyn E.; Bianco, Laura; Eluszkiewicz, Janusz; Hirsch, Adam; MacDonald, Clinton; Nehrkorn, Thomas; Fischer, Marc L.

    2008-11-21

    Methane mixing ratios measured at a tall-tower are compared to model predictions to estimate surface emissions of CH{sub 4} in Central California for October-December 2007 using an inverse technique. Predicted CH{sub 4} mixing ratios are calculated based on spatially resolved a priori CH{sub 4} emissions and simulated atmospheric trajectories. The atmospheric trajectories, along with surface footprints, are computed using the Weather Research and Forecast (WRF) coupled to the Stochastic Time-Inverted Lagrangian Transport (STILT) model. An uncertainty analysis is performed to provide quantitative uncertainties in estimated CH{sub 4} emissions. Three inverse model estimates of CH{sub 4} emissions are reported. First, linear regressions of modeled and measured CH{sub 4} mixing ratios obtain slopes of 0.73 {+-} 0.11 and 1.09 {+-} 0.14 using California specific and Edgar 3.2 emission maps respectively, suggesting that actual CH{sub 4} emissions were about 37 {+-} 21% higher than California specific inventory estimates. Second, a Bayesian 'source' analysis suggests that livestock emissions are 63 {+-} 22% higher than the a priori estimates. Third, a Bayesian 'region' analysis is carried out for CH{sub 4} emissions from 13 sub-regions, which shows that inventory CH{sub 4} emissions from the Central Valley are underestimated and uncertainties in CH{sub 4} emissions are reduced for sub-regions near the tower site, yielding best estimates of flux from those regions consistent with 'source' analysis results. The uncertainty reductions for regions near the tower indicate that a regional network of measurements will be necessary to provide accurate estimates of surface CH{sub 4} emissions for multiple regions.

  10. Modelling the atmosphere of the carbon-rich Mira RU Virginis

    NASA Astrophysics Data System (ADS)

    Rau, G.; Paladini, C.; Hron, J.; Aringer, B.; Groenewegen, M. A. T.; Nowotny, W.

    2015-11-01

    Context. We study the atmosphere of the carbon-rich Mira RU Vir using the mid-infrared high spatial resolution interferometric observations from VLTI/MIDI. Aims: The aim of this work is to analyse the atmosphere of the carbon-rich Mira RU Vir with hydrostatic and dynamic models, in this way deepening the knowledge of the dynamic processes at work in carbon-rich Miras. Methods: We compare spectro-photometric and interferometric measurements of this carbon-rich Mira AGB star with the predictions of different kinds of modelling approaches (hydrostatic model atmospheres plus MOD-More Of Dusty, self-consistent dynamic model atmospheres). A geometric model fitting tool is used for a first interpretation of the interferometric data. Results: The results show that a joint use of different kinds of observations (photometry, spectroscopy, interferometry) is essential for shedding light on the structure of the atmosphere of a carbon-rich Mira. The dynamic model atmospheres fit the ISO spectrum well in the wavelength range λ = [2.9,25.0] μm. Nevertheless, a discrepancy is noticeable both in the SED (visible) and in the interferometric visibilities (shape and level), which is a possible explanation are intra-/inter-cycle variations in the dynamic model atmospheres, as well as in the observations. The presence of a companion star and/or a disk or a decrease in mass loss within the past few hundred years cannot be excluded, but these explanations are considered unlikely. Based on observations made with ESO telescopes at La Silla Paranal Observatory under programme IDs: 085.D-0756 and 093. D-0708.Appendix A is available in electronic form at http://www.aanda.org

  11. The carbon star adventure: modelling atmospheres of a set of C-rich AGB stars

    NASA Astrophysics Data System (ADS)

    Rau, Gioia; Paladini, Claudia; Hron, Josef; Aringer, Bernard; Erikssonn, Kjell; Groenewegen, Martin

    2015-08-01

    We study the atmospheres of a set of carbon rich AGB stars to improve our understanding of the dynamic processes happening in there.For the first time we compare in a systematic way spectrometric, photometric and mid-infrared (VLTI/MIDI) interferometric measurements with different type of model atmospheres: (1) hydrostatic models + MOD-dusty models (Groenewegen, 2012) added a posteriori; (2) self-consistent dynamic model atmospheres (Eriksson et al. 2014). These allow to interpret in a coherent way the dynamic behavior of gas and dust. In addition, the geometric model fitting tool for interferometric data GEM-FIND is applied to carry out a first interpretation of the structural environment of the stars.The results underline that the joint use of different kind of observations, as photometry, spectroscopy and interferometry, is essential for understanding and modeling the atmosphere of pulsating C-rich AGB stars. For our first target, the carbon-rich Mira star RU Vir, the dynamic model atmospheres fit well the ISO/SWS spectra in the wavelength range λ = [2.9, 13.0] μm. However, the object turned out to be “peculiar”: we notice a discrepancy in the visible part of the SED, and in the visibilities. Possible causes are intra/inter-cycle variations in the dynamic model atmospheres, and an eventual presence of a companion star and/or disk or clumps in the atmosphere of RU Vir (Rau et al. subm.). Results on further targets will also be presented.The increased sample of C-rich stars of this work provides crucial constraints for the atmospheric structure and the formation of SiC. Moreover the second generation VLTI instrument MATISSE will be a perfect tool to detect and study asymmetries, as it will allow interferometric imaging in the L, M, and N bands.

  12. Atmospheric Verification of Point Source Fossil Fuel CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Keller, E. D.; Norris, M. W.; Wiltshire, R.; Baisden, W. T.; Brailsford, G. W.; Bromley, T.

    2015-12-01

    Large point sources (electricity generation and large-scale industry) make up roughly one third of all fossil fuel CO2 (CO2ff) emissions. Currently, these emissions are determined from self-reported inventory data, and sometimes from smokestack emissions monitoring, and the uncertainty in emissions from individual power plants is about 20%. We examine the utility of atmospheric 14C measurements combined with atmospheric transport modelling as a tool for independently quantifying point source CO2ff emissions, to both improve the accuracy of the reported emissions and for verification as we move towards a regulatory environment. We use the Kapuni Gas Treatment Facility as a test case. It is located in rural New Zealand with no other significant fossil fuel CO2 sources nearby, and emits CO2ff at ~0.1 Tg carbon per year. We use several different sampling methods to determine the 14C and hence the CO2ff content downwind of the emission source: grab flask samples of whole air; absorption of CO2 into sodium hydroxide integrated over many hours; and plant material which faithfully records the 14C content of assimilated CO2. We use a plume dispersion model to compare the reported emissions with our observed CO2ff mole fractions. We show that the short-term variability in plume dispersion makes it difficult to interpret the grab flask sample results, whereas the variability is averaged out in the integrated samples and we obtain excellent agreement between the reported and observed emissions, indicating that the 14C method can reliably be used to evaluated point source emissions.

  13. Inventory of U.S. 2012 dioxin emissions to atmosphere.

    PubMed

    Dwyer, Henri; Themelis, Nickolas J

    2015-12-01

    In 2006, the U.S. EPA published an inventory of dioxin emissions for the U.S. covering the period from 1987-2000. This paper is an updated inventory of all U.S. dioxin emissions to the atmosphere in the year 2012. The sources of emissions of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), collectively referred to in this paper as "dioxins", were separated into two classes: controlled industrial and open burning sources. Controlled source emissions decreased 95.5% from 14.0 kg TEQ in 1987 to 0.6 kg in 2012. Open burning source emissions increased from 2.3 kg TEQ in 1987 to 2.9 kg in 2012. The 2012 dioxin emissions from 53 U.S. waste-to-energy (WTE) power plants were compiled on the basis of detailed data obtained from the two major U.S. WTE companies, representing 84% of the total MSW combusted (27.4 million metric tons). The dioxin emissions of all U.S. WTE plants in 2012 were 3.4 g TEQ and represented 0.54% of the controlled industrial dioxin emissions, and 0.09% of all dioxin emissions from controlled and open burning sources. Copyright © 2015. Published by Elsevier Ltd.

  14. Role of regional wetland emissions in atmospheric methane variability

    NASA Astrophysics Data System (ADS)

    McNorton, J.; Gloor, E.; Wilson, C.; Hayman, G. D.; Gedney, N.; Comyn-Platt, E.; Marthews, T.; Parker, R. J.; Boesch, H.; Chipperfield, M. P.

    2016-11-01

    Atmospheric methane (CH4) accounts for 20% of the total direct anthropogenic radiative forcing by long-lived greenhouse gases. Surface observations show a pause (1999-2006) followed by a resumption in CH4 growth, which remain largely unexplained. Using a land surface model, we estimate wetland CH4 emissions from 1993 to 2014 and study the regional contributions to changes in atmospheric CH4. Atmospheric model simulations using these emissions, together with other sources, compare well with surface and satellite CH4 data. Modeled global wetland emissions vary by ±3%/yr (σ = 4.8 Tg), mainly due to precipitation-induced changes in wetland area, but the integrated effect makes only a small contribution to the pause in CH4 growth from 1999 to 2006. Increasing temperature, which increases wetland area, drives a long-term trend in wetland CH4 emissions of +0.2%/yr (1999 to 2014). The increased growth post-2006 was partly caused by increased wetland emissions (+3%), mainly from Tropical Asia, Southern Africa, and Australia.

  15. Mercury emission to atmosphere from primary Zn production in China.

    PubMed

    Li, Guanghui; Feng, Xinbin; Li, Zhonggen; Qiu, Guangle; Shang, Lihai; Liang, Peng; Wang, Dingyong; Yang, Yongkui

    2010-09-15

    Emissions of mercury (Hg) to air have regional and global impacts through long range transport in the atmosphere. Primary Zn production is regarded as an important anthropogenic Hg source in China, but research on its Hg emission is limited. To gain a better understanding of Hg emissions from Zn production activities in China, field investigations at four industrial-scale Zn production plants using electrostatic process with Hg removal (HP-WR), electrostatic process without Hg removal (HP-WOR), retort Zn production (RZ), imperial smelting process (ISP), and one artisanal Zn smelting process (AZ) were carried out. In the investigation, Hg emission factors are defined as how much Hg was emitted to the atmosphere per ton Zn produced during various Zn production methods and were estimated by using mass balance method. The results showed that the estimated Hg emission factors of Zn production were 5.7+/-4.0 g Hg t(-1) Zn for HP-WR, 31+/-22 g Hg t(-1) Zn for HP-WOR, 34+/-71 g Hg t(-1) Zn for RZ, 122+/-122 g Hg t(-1) Zn g t(-1) for ISP, and 75+/-115 g Hg t(-1) Zn for AZ. Approximately 80.7-104.2 t year(-1) of Hg was emitted to atmosphere from primary Zn production during the period of 2002-2006 in China. Copyright 2010 Elsevier B.V. All rights reserved.

  16. Methane Emission and Milk Production of Dairy Cows Grazing Pastures Rich in Legumes or Rich in Grasses in Uruguay

    PubMed Central

    Dini, Yoana; Gere, José; Briano, Carolina; Manetti, Martin; Juliarena, Paula; Picasso, Valentin; Gratton, Roberto; Astigarraga, Laura

    2012-01-01

    Simple Summary GHGs emissions are relevant in evaluating environmental impact of farming systems. Methane (CH4) produced by enteric fermentation accounts for half of all anthropogenic emissions of GHGs in Uruguay, where ruminant production is based on year round grazing of forages. Here we compared milk production and CH4 emissions by dairy cows grazing two contrasting mixed pastures (rich in legumes or rich in grasses) using the SF6 tracer technique adapted to collect breath samples over 5-days periods. There were no differences in milk or CH4 production between the contrasting pastures, probably because of the high herbage allowance that enabled selective grazing by cows. Abstract Understanding the impact of changing pasture composition on reducing emissions of GHGs in dairy grazing systems is an important issue to mitigate climate change. The aim of this study was to estimate daily CH4 emissions of dairy cows grazing two mixed pastures with contrasting composition of grasses and legumes: L pasture with 60% legumes on Dry Matter (DM) basis and G pasture with 75% grasses on DM basis. Milk production and CH4 emissions were compared over two periods of two weeks during spring using eight lactating Holstein cows in a 2 × 2 Latin square design. Herbage organic matter intake (HOMI) was estimated by chromic oxide dilution and herbage organic matter digestibility (OMD) was estimated by faecal index. Methane emission was estimated by using the sulfur hexafluoride (SF6) tracer technique adapted to collect breath samples over 5-day periods. OMD (0.71) and HOMI (15.7 kg OM) were not affected by pasture composition. Milk production (20.3 kg/d), milk fat yield (742 g/d) and milk protein yield (667 g/d) were similar for both pastures. This may be explained by the high herbage allowance (30 kg DM above 5 cm/cow) which allowed the cows to graze selectively, in particular in grass sward. Similarly, methane emission expressed as absolute value (368 g/d or 516 L/d) or expressed as

  17. Atmospheric benzenoid emissions from plants rival those from fossil fuels

    SciTech Connect

    Misztal, P. K.; Hewitt, C. N.; Wildt, J.; Blande, J. D.; Eller, A. S.D.; Fares, S.; Gentner, D. R.; Gilman, J. B.; Graus, M.; Greenberg, J.; Guenther, A. B.; Hansel, A.; Harley, P.; Huang, M.; Jardine, K.; Karl, T.; Kaser, L.; Keutsch, F. N.; Kiendler-Scharr, A.; Kleist, E.; Lerner, B. M.; Li, T.; Mak, J.; Nölscher, A. C.; Schnitzhofer, R.; Sinha, V.; Thornton, B.; Warneke, C.; Wegener, F.; Werner, C.; Williams, J.; Worton, D. R.; Yassaa, N.; Goldstein, A. H.

    2015-07-13

    Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functions of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y-1), pointing to the importance of these natural emissions in atmospheric physics and chemistry.

  18. Atmospheric benzenoid emissions from plants rival those from fossil fuels.

    PubMed

    Misztal, P K; Hewitt, C N; Wildt, J; Blande, J D; Eller, A S D; Fares, S; Gentner, D R; Gilman, J B; Graus, M; Greenberg, J; Guenther, A B; Hansel, A; Harley, P; Huang, M; Jardine, K; Karl, T; Kaser, L; Keutsch, F N; Kiendler-Scharr, A; Kleist, E; Lerner, B M; Li, T; Mak, J; Nölscher, A C; Schnitzhofer, R; Sinha, V; Thornton, B; Warneke, C; Wegener, F; Werner, C; Williams, J; Worton, D R; Yassaa, N; Goldstein, A H

    2015-07-13

    Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functions of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y(-1)), pointing to the importance of these natural emissions in atmospheric physics and chemistry.

  19. Atmospheric benzenoid emissions from plants rival those from fossil fuels

    DOE PAGES

    Misztal, P. K.; Hewitt, C. N.; Wildt, J.; ...

    2015-07-13

    Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functionsmore » of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y-1), pointing to the importance of these natural emissions in atmospheric physics and chemistry.« less

  20. Atmospheric benzenoid emissions from plants rival those from fossil fuels

    NASA Astrophysics Data System (ADS)

    Misztal, P. K.; Hewitt, C. N.; Wildt, J.; Blande, J. D.; Eller, A. S. D.; Fares, S.; Gentner, D. R.; Gilman, J. B.; Graus, M.; Greenberg, J.; Guenther, A. B.; Hansel, A.; Harley, P.; Huang, M.; Jardine, K.; Karl, T.; Kaser, L.; Keutsch, F. N.; Kiendler-Scharr, A.; Kleist, E.; Lerner, B. M.; Li, T.; Mak, J.; Nölscher, A. C.; Schnitzhofer, R.; Sinha, V.; Thornton, B.; Warneke, C.; Wegener, F.; Werner, C.; Williams, J.; Worton, D. R.; Yassaa, N.; Goldstein, A. H.

    2015-07-01

    Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functions of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y-1), pointing to the importance of these natural emissions in atmospheric physics and chemistry.

  1. Atmospheric benzenoid emissions from plants rival those from fossil fuels

    PubMed Central

    Misztal, P.K.; Hewitt, C.N.; Wildt, J.; Blande, J.D.; Eller, A.S.D.; Fares, S.; Gentner, D.R.; Gilman, J.B.; Graus, M.; Greenberg, J.; Guenther, A.B.; Hansel, A.; Harley, P.; Huang, M.; Jardine, K.; Karl, T.; Kaser, L.; Keutsch, F.N.; Kiendler-Scharr, A.; Kleist, E.; Lerner, B.M.; Li, T.; Mak, J.; Nölscher, A.C.; Schnitzhofer, R.; Sinha, V.; Thornton, B.; Warneke, C.; Wegener, F.; Werner, C.; Williams, J.; Worton, D.R.; Yassaa, N.; Goldstein, A.H.

    2015-01-01

    Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functions of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y−1), pointing to the importance of these natural emissions in atmospheric physics and chemistry. PMID:26165168

  2. Estimate of mercury emissions to the atmosphere from petroleum.

    PubMed

    Wilhelm, S M

    2001-12-15

    An estimate of the contribution of mercury to the atmospheric environment from petroleum processed in the United States is constructed from recent data. The estimate is based on a mass balance approach for mercury in crude oil, in refined products, and in waste streams (air, water, solid waste) from refineries. Although there are insufficient data at present to have a high degree of confidence in the mean amount and range of mercury concentrations in crude oil or in refined products, the framework of the estimate should assist direction for the acquisition of additional data. On the basis of selected data that put the estimated mean concentration of total mercury in crude oil close to 10 ppb, it is calculated that the total amount of mercury in U.S. petroleum processed yearly is slightly over 8000 kg/yr. Of this amount, approximately 6000 kg/yr is estimated to be emitted to the atmosphere from combustion of liquid hydrocarbon fuels, which represents about 10% of the U.S. yearly emission rate of atmospheric mercury from coal combustion. The material balance predicts that the amount of mercury in air emissions from all U.S. refineries is on the order of 1500 kg/yr based on the assumption that fugitive mercury emissions from refineries are negligible. Atmospheric emissions of mercury from fuel oil burned in the United States are estimated in the U.S. EPA Mercury Report to Congress to be approximately 10000 kg/yr, and this estimate may be in error on the high side by a factor of 3-10. If the mean amounts of mercury in U.S. distillate and residual fuel oils are in the range of 5-15 ppb, as suggested by more recent data, then U.S. fuel oil combustion should contribute no more that about 1000-3000 kg/yr (emission ratio = 1) of mercury to the atmospheric burden.

  3. Atmospheric emission of polychlorinated biphenyls from multiple industrial thermal processes.

    PubMed

    Liu, Guorui; Zheng, Minghui; Cai, Mingwei; Nie, Zhiqiang; Zhang, Bing; Liu, Wenbin; Du, Bing; Dong, Shujun; Hu, Jicheng; Xiao, Ke

    2013-03-01

    In this study, field measurements were conducted to estimate and characterize the atmospheric emission levels and profiles of polychlorinated biphenyls (PCBs) from multiple industrial thermal processes. The emission levels and profiles of PCBs from five types of thermal processes at twenty-three plants were studied and compared with eight processes reported in our previous studies. Correlation analysis was preformed to identify a marker congener for emission of ΣPCB. A significant correlation was observed between congener CB-118 and ΣPCB (R(2)=0.65 and p<0.01), which suggests that CB-118 is a good marker congener for emission of ΣPCB. The profiles of PCBs emitted from the thirteen thermal processes were compared, and this information could be used for studying source-receptor relationships and identifying the specific sources of PCBs. To prioritize the sources for control, the concentrations of PCBs from thirteen industrial thermal sources were compared. The PCB concentrations from secondary zinc smelting and thermal wire reclamation were about one to three order magnitude higher than those of other sources, which suggests that these two sources be given priority in PCB source control. Finally, the atmospheric emission factors of PCBs from the thirteen industrial sources were summarized, and these data will be useful for developing an integrated emission inventory of PCBs.

  4. Atmospheric emission characterization of Marcellus shale natural gas development sites.

    PubMed

    Goetz, J Douglas; Floerchinger, Cody; Fortner, Edward C; Wormhoudt, Joda; Massoli, Paola; Knighton, W Berk; Herndon, Scott C; Kolb, Charles E; Knipping, Eladio; Shaw, Stephanie L; DeCarlo, Peter F

    2015-06-02

    Limited direct measurements of criteria pollutants emissions and precursors, as well as natural gas constituents, from Marcellus shale gas development activities contribute to uncertainty about their atmospheric impact. Real-time measurements were made with the Aerodyne Research Inc. Mobile Laboratory to characterize emission rates of atmospheric pollutants. Sites investigated include production well pads, a well pad with a drill rig, a well completion, and compressor stations. Tracer release ratio methods were used to estimate emission rates. A first-order correction factor was developed to account for errors introduced by fenceline tracer release. In contrast to observations from other shale plays, elevated volatile organic compounds, other than CH4 and C2H6, were generally not observed at the investigated sites. Elevated submicrometer particle mass concentrations were also generally not observed. Emission rates from compressor stations ranged from 0.006 to 0.162 tons per day (tpd) for NOx, 0.029 to 0.426 tpd for CO, and 67.9 to 371 tpd for CO2. CH4 and C2H6 emission rates from compressor stations ranged from 0.411 to 4.936 tpd and 0.023 to 0.062 tpd, respectively. Although limited in sample size, this study provides emission rate estimates for some processes in a newly developed natural gas resource and contributes valuable comparisons to other shale gas studies.

  5. The influence of atmospheric pressure on landfill methane emissions

    SciTech Connect

    Czepiel, P.M.; Shorter, J.H.; Mosher, B.; Allwine, E.; McManus, J.B.; Harriss, R.C.; Kolb, C.E.; Lamb, B.K

    2003-07-01

    Landfills are the largest source of anthropogenic methane (CH{sub 4}) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH{sub 4} emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH{sub 4} emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5-8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m{sup 3} CH{sub 4} min{sup -1}. A simple regression model of our results was used to calculate an annual emission rate of 8.4x10{sup 6} m{sup 3} CH{sub 4} year{sup -1}. These data, along with CH{sub 4} oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH{sub 4} generation at this landfill. A reported gas collection rate of 7.1x10{sup 6} m{sup 3} CH{sub 4} year{sup -1} and an estimated annual rate of CH{sub 4} oxidation by cover soils of 1.2x10{sup 6} m{sup 3} CH{sub 4} year{sup -1} resulted in a calculated annual CH{sub 4} generation rate of 16.7x10{sup 6} m{sup 3} CH{sub 4} year{sup -1}. These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential.

  6. Atmospheric Carbon Tetrachloride: Mysterious Emissions Gap Almost Closed

    NASA Astrophysics Data System (ADS)

    Liang, Q.; Newman, P. A.; Reimann, S.

    2016-12-01

    Carbon tetrachloride (CCl4) is a major ozone-depleting substance and its production and consumption is controlled under the Montreal Protocol for emissive uses. The most recent WMO/UNEP Scientific Assessment of Ozone Depletion [WMO, 2014] estimated a 2007-2012 CCl4 bottom-up emission of 1-4 Gg yr-1, based on country-by-country reports to UNEP, vs. a global top-down emissions estimate of 57 Gg yr-1, based on atmospheric measurements. To understand the gap between the top-down and bottom-up emissions estimates, a CCl4 activity was formed under the auspices of the Stratosphere-Troposphere Processes And their Role in Climate (SPARC) project. Several new findings were brought forward by the SPARC CCl4 activity. CCl4 is destroyed in the stratosphere, oceans, and soils. The total lifetime estimate has been increased from 26 to 33 years. The new 33-year total lifetime lowers the top-down emissions estimate to 40 (25-55) Gg yr-1. In addition, a persistent hemispheric difference implies substantial ongoing Northern Hemisphere emissions, yielding an independent emissions estimate of 30 Gg yr-1. The combination of these two yields an emissions estimate of 35 Gg yr-1. Regional estimates have been made for Australia, North America, East Asia, and Western Europe. The sum of these estimates results in emissions of 21 Gg yr-1, albeit this does not include all regions of the world. Four bottom-up CCl4 emissions pathways have been identified, i.e., fugitive, unreported non-feedstock, unreported inadvertent, and legacy emissions. The new industrial bottom-up emissions estimate includes emissions from chloromethanes plants (13 Gg yr-1) and feedstock fugitive emissions (2 Gg yr-1). When combined with legacy emissions and unreported inadvertent emissions ( 10 Gg yr-1), the total global emissions are 20±5 Gg yr-1. While the new bottom-up value is still less than the aggregated top-down values, these estimates reconcile the CCl4 budget discrepancy when considered at the edges of their

  7. Man's emissions of carbon monoxide and hydrocarbons into the atmosphere

    NASA Astrophysics Data System (ADS)

    Cullis, C. F.; Hirschler, M. M.

    Estimates have been made of the amounts of CO and total hydrocarbons (HC) released into the atmosphere as a result of man's activities and influence. Emissions have generally been calculated from the annual consumption of the various source materials and the appropriate emission factors. The combustion of petroleum products remains by far the largest source of CO and the amounts of this gas generated therefrom are rising steadily. Refuse incineration also makes a sizeable contribution but coal combustion is decreasing in importance. Petroleum combustion and solvent use are primarily responsible for man's liberation of HC into the atmosphere and the amounts derived from both sources are increasing rapidly. Enteric fermentation in animals and emissions from sediments of rice paddies (both essentially controlled by man) also contribute substantially to the amounts of methane released into the atmosphere. However, although man-made, and man-controlled natural, emissions of both CO and total HC are still increasing, the rate of increase is falling and possible reasons for this are suggested.

  8. Atmospheric measurement of point source fossil CO2 emissions

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Keller, E. D.; Baisden, T.; Brailsford, G.; Bromley, T.; Norris, M.; Zondervan, A.

    2014-05-01

    We use the Kapuni Gas Treatment Plant to examine methodologies for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes CO2 from locally extracted natural gas and vents that CO2 to the atmosphere, at a rate of ~0.1 Tg carbon per year. The plant is located in a rural dairy farming area, with no other significant CO2ff sources nearby, but large, diurnally varying, biospheric CO2 fluxes from the surrounding highly productive agricultural grassland. We made flask measurements of CO2 and 14CO2 (from which we derive the CO2ff component) and in situ measurements of CO2 downwind of the Kapuni plant, using a Helikite to sample transects across the emission plume from the surface up to 100 m above ground level. We also determined the surface CO2ff content averaged over several weeks from the 14C content of grass samples collected from the surrounding area. We use the WindTrax plume dispersion model to compare the atmospheric observations with the emissions reported by the Kapuni plant, and to determine how well atmospheric measurements can constrain the emissions. The model has difficulty accurately capturing the fluctuations and short-term variability in the Helikite samples, but does quite well in representing the observed CO2ff in 15 min averaged surface flask samples and in ~ one week integrated CO2ff averages from grass samples. In this pilot study, we found that using grass samples, the modeled and observed CO2ff emissions averaged over one week agreed to within 30%. The results imply that greater verification accuracy may be achieved by including more detailed meteorological observations and refining 14C sampling strategies.

  9. Atmospheric measurement of point source fossil fuel CO2 emissions

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Keller, E. D.; Baisden, W. T.; Brailsford, G.; Bromley, T.; Norris, M.; Zondervan, A.

    2013-11-01

    We use the Kapuni Gas Treatment Plant to examine methodologies for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes CO2 from locally extracted natural gas and vents that CO2 to the atmosphere, at a rate of ~0.1 Tg carbon per year. The plant is located in a rural dairy farming area, with no other significant CO2ff sources nearby, but large, diurnally varying, biospheric CO2 fluxes from the surrounding highly productive agricultural grassland. We made flask measurements of CO2 and 14CO2 (from which we derive the CO2ff component) and in situ measurements of CO2 downwind of the Kapuni plant, using a Helikite to sample transects across the emission plume from the surface up to 100 m a.g.l. We also determined the surface CO2ff content averaged over several weeks from the 14CO2 content of grass samples collected from the surrounding area. We use the WindTrax plume dispersion model to compare the atmospheric observations with the emissions reported by the Kapuni plant, and to determine how well atmospheric measurements can constrain the emissions. The model has difficulty accurately capturing the fluctuations and short-term variability in the Helikite samples, but does quite well in representing the observed CO2ff in 15 min averaged surface flask samples and in ~1 week integrated CO2ff averages from grass samples. In this pilot study, we found that using grass samples, the modeled and observed CO2ff emissions averaged over one week agreed to within 30%. The results imply that greater verification accuracy may be achieved by including more detailed meteorological observations and refining 14CO2 sampling strategies.

  10. MODELING ATMOSPHERIC EMISSION FOR CMB GROUND-BASED OBSERVATIONS

    SciTech Connect

    Errard, J.; Borrill, J.; Ade, P. A. R.; Akiba, Y.; Chinone, Y.; Arnold, K.; Atlas, M.; Barron, D.; Elleflot, T.; Baccigalupi, C.; Fabbian, G.; Boettger, D.; Chapman, S.; Cukierman, A.; Delabrouille, J.; Ducout, A.; Feeney, S.; Feng, C.; and others

    2015-08-10

    Atmosphere is one of the most important noise sources for ground-based cosmic microwave background (CMB) experiments. By increasing optical loading on the detectors, it amplifies their effective noise, while its fluctuations introduce spatial and temporal correlations between detected signals. We present a physically motivated 3D-model of the atmosphere total intensity emission in the millimeter and sub-millimeter wavelengths. We derive a new analytical estimate for the correlation between detectors time-ordered data as a function of the instrument and survey design, as well as several atmospheric parameters such as wind, relative humidity, temperature and turbulence characteristics. Using an original numerical computation, we examine the effect of each physical parameter on the correlations in the time series of a given experiment. We then use a parametric-likelihood approach to validate the modeling and estimate atmosphere parameters from the polarbear-i project first season data set. We derive a new 1.0% upper limit on the linear polarization fraction of atmospheric emission. We also compare our results to previous studies and weather station measurements. The proposed model can be used for realistic simulations of future ground-based CMB observations.

  11. Modeling Atmospheric Emission for CMB Ground-based Observations

    NASA Astrophysics Data System (ADS)

    Errard, J.; Ade, P. A. R.; Akiba, Y.; Arnold, K.; Atlas, M.; Baccigalupi, C.; Barron, D.; Boettger, D.; Borrill, J.; Chapman, S.; Chinone, Y.; Cukierman, A.; Delabrouille, J.; Dobbs, M.; Ducout, A.; Elleflot, T.; Fabbian, G.; Feng, C.; Feeney, S.; Gilbert, A.; Goeckner-Wald, N.; Halverson, N. W.; Hasegawa, M.; Hattori, K.; Hazumi, M.; Hill, C.; Holzapfel, W. L.; Hori, Y.; Inoue, Y.; Jaehnig, G. C.; Jaffe, A. H.; Jeong, O.; Katayama, N.; Kaufman, J.; Keating, B.; Kermish, Z.; Keskitalo, R.; Kisner, T.; Le Jeune, M.; Lee, A. T.; Leitch, E. M.; Leon, D.; Linder, E.; Matsuda, F.; Matsumura, T.; Miller, N. J.; Myers, M. J.; Navaroli, M.; Nishino, H.; Okamura, T.; Paar, H.; Peloton, J.; Poletti, D.; Puglisi, G.; Rebeiz, G.; Reichardt, C. L.; Richards, P. L.; Ross, C.; Rotermund, K. M.; Schenck, D. E.; Sherwin, B. D.; Siritanasak, P.; Smecher, G.; Stebor, N.; Steinbach, B.; Stompor, R.; Suzuki, A.; Tajima, O.; Takakura, S.; Tikhomirov, A.; Tomaru, T.; Whitehorn, N.; Wilson, B.; Yadav, A.; Zahn, O.

    2015-08-01

    Atmosphere is one of the most important noise sources for ground-based cosmic microwave background (CMB) experiments. By increasing optical loading on the detectors, it amplifies their effective noise, while its fluctuations introduce spatial and temporal correlations between detected signals. We present a physically motivated 3D-model of the atmosphere total intensity emission in the millimeter and sub-millimeter wavelengths. We derive a new analytical estimate for the correlation between detectors time-ordered data as a function of the instrument and survey design, as well as several atmospheric parameters such as wind, relative humidity, temperature and turbulence characteristics. Using an original numerical computation, we examine the effect of each physical parameter on the correlations in the time series of a given experiment. We then use a parametric-likelihood approach to validate the modeling and estimate atmosphere parameters from the polarbear-i project first season data set. We derive a new 1.0% upper limit on the linear polarization fraction of atmospheric emission. We also compare our results to previous studies and weather station measurements. The proposed model can be used for realistic simulations of future ground-based CMB observations.

  12. Atmospheric Simulation of Time-Dependent Landfill Methane Emissions

    NASA Astrophysics Data System (ADS)

    Taylor, D.; Delkash, M.; Chow, F. K.; Imhoff, P. T.

    2016-12-01

    Landfill methane emissions are difficult to estimate due to limited observations and data uncertainty. A surface flux drag law for landfill methane emissions is added to the Weather Research and Forecasting model (WRF) to predict emissions based on soil and atmospheric methane concentrations and horizontal wind speed, based on similar surface flux equations used by WRF for heat and moisture. Simulations of landfill methane emissions and the tracer dilution method used to estimate landfill methane emissions are run over different time periods for Sandtown Landfill in Delaware, USA. Two questions are explored through analysis of the simulations: how does the accuracy of the tracer dilution method change over the course of the day, and how do variations in wind speed affect the variability of landfill methane emissions on short time scales (a few hours). Models and observations show that soil methane concentration does not change significantly on small time scales, so variability in emissions over a one to two hour measurement period can be attributed to variations in wind speed. The values used for soil methane concentration in the daily cover and intermediate cover are taken from the California Landfill Methane Inventory Model (CALMIM), which is used to simulate soil processes and predict soil methane concentrations for Sandtown Landfill.

  13. Airborne interferometer for atmospheric emission and solar absorption.

    PubMed

    Keith, D W; Dykema, J A; Hu, H; Lapson, L; Anderson, J G

    2001-10-20

    The interferometer for emission and solar absorption (INTESA) is an infrared spectrometer designed to study radiative transfer in the troposphere and lower stratosphere from a NASA ER-2 aircraft. The Fourier-transform spectrometer (FTS) operates from 0.7 to 50 mum with a resolution of 0.7 cm(-1). The FTS observes atmospheric thermal emission from multiple angles above and below the aircraft. A heliostat permits measurement of solar absorption spectra. INTESA's calibration system includes three blackbodies to permit in-flight assessment of radiometric error. Results suggest that the in-flight radiometric accuracy is ~0.5 K in the mid-infrared.

  14. Spatial and Temporal Patterns in Carbon Emissions to the Atmosphere

    NASA Astrophysics Data System (ADS)

    Broniak, C. T.; Blasing, T. J.; Marland, G.

    2003-12-01

    Data on global fossil-fuel emissions of CO2 to the atmosphere for year 2000 show that the range of national average per capita emissions, in metric tons of carbon per person, includes values of 5.40 for the United States, 2.61 for Germany, 0.29 for India and 0.04 for Liberia. This range is more than two orders of magnitude. Similar data on national fossil-fuel emissions for the United States vary by more than an order of magnitude, from 34.18 metric tons of carbon per person for Wyoming to 2.70 for California. The state data also show differing patterns of change over time. The Kyoto Protocol would require ratifying developed countries to reduce greenhouse gas emissions to quantified negotiated targets. The concept of contraction and convergence (C&C) has been widely touted as a possible basis for ultimate, more strict limits on greenhouse gas emissions. The idea of C&C is that per-capita emissions of CO2 for all countries would converge toward some common value that is consistent with stabilization of global climate. The U.S., on the other hand, has proposed intensity-based emissions targets whereby goals would be defined in terms of emissions per unit of gross domestic product, or perhaps emissions per unit of output for specific activities. This paper describes the data set on U.S. CO2 emissions by state, and begins to explore the patterns between states and over time.

  15. European emissions of halogenated greenhouse gases inferred from atmospheric measurements.

    PubMed

    Keller, Christoph A; Hill, Matthias; Vollmer, Martin K; Henne, Stephan; Brunner, Dominik; Reimann, Stefan; O'Doherty, Simon; Arduini, Jgor; Maione, Michela; Ferenczi, Zita; Haszpra, Laszlo; Manning, Alistair J; Peter, Thomas

    2012-01-03

    European emissions of nine representative halocarbons (CFC-11, CFC-12, Halon 1211, HCFC-141b, HCFC-142b, HCFC-22, HFC-125, HFC-134a, HFC-152a) are derived for the year 2009 by combining long-term observations in Switzerland, Italy, and Ireland with campaign measurements from Hungary. For the first time, halocarbon emissions over Eastern Europe are assessed by top-down methods, and these results are compared to Western European emissions. The employed inversion method builds on least-squares optimization linking atmospheric observations with calculations from the Lagrangian particle dispersion model FLEXPART. The aggregated halocarbon emissions over the study area are estimated at 125 (106-150) Tg of CO(2) equiv/y, of which the hydrofluorocarbons (HFCs) make up the most important fraction with 41% (31-52%). We find that chlorofluorocarbon (CFC) emissions from banks are still significant and account for 35% (27-43%) of total halocarbon emissions in Europe. The regional differences in per capita emissions are only small for the HFCs, while emissions of CFCs and hydrochlorofluorocarbons (HCFCs) tend to be higher in Western Europe compared to Eastern Europe. In total, the inferred per capita emissions are similar to estimates for China, but 3.5 (2.3-4.5) times lower than for the United States. Our study demonstrates the large benefits of adding a strategically well placed measurement site to the existing European observation network of halocarbons, as it extends the coverage of the inversion domain toward Eastern Europe and helps to better constrain the emissions over Central Europe.

  16. Radiative transfer in CO2-rich atmospheres: 1. Collisional line mixing implies a colder early Mars

    NASA Astrophysics Data System (ADS)

    Ozak, N.; Aharonson, O.; Halevy, I.

    2016-06-01

    Fast and accurate radiative transfer methods are essential for modeling CO2-rich atmospheres, relevant to the climate of early Earth and Mars, present-day Venus, and some exoplanets. Although such models already exist, their accuracy may be improved as better theoretical and experimental constraints become available. Here we develop a unidimensional radiative transfer code for CO2-rich atmospheres, using the correlated k approach and with a focus on modeling early Mars. Our model differs from existing models in that it includes the effects of CO2 collisional line mixing in the calculation of the line-by-line absorption coefficients. Inclusion of these effects results in model atmospheres that are more transparent to infrared radiation and, therefore, in colder surface temperatures at radiative-convective equilibrium, compared with results of previous studies. Inclusion of water vapor in the model atmosphere results in negligible warming due to the low atmospheric temperatures under a weaker early Sun, which translate into climatically unimportant concentrations of water vapor. Overall, the results imply that sustained warmth on early Mars would not have been possible with an atmosphere containing only CO2 and water vapor, suggesting that other components of the early Martian climate system are missing from current models or that warm conditions were not long lived.

  17. Method of reducing chlorofluorocarbon refrigerant emissions in the atmosphere

    SciTech Connect

    DeVault, R.C.; Fairchild, P.D.; Biermann, W.J.

    1990-06-19

    This patent describes a method of reducing escape of refrigerant emissions to the atmosphere during removal of a chlorofluorocarbon refrigerant from a vapor compression cooling system or heat pump. The method comprises contacting the chlorofluorocarbon refrigerant during removal with a sorbent material into which the chlorofluorocarbon refrigerant can be dissolved, the sorbent material being selected from the group consisting of N-methyl-2-pyrrolidone, ethyl tetrahydro furfuryl ether, tetramethylene glycol dimethylether, triethylene glycol dimethylether, N,N-dimethyl formamide, dimethylamides, and tetrachloroethane.

  18. Oceanic Emissions and Atmospheric Depositions of Volatile Organic Compounds

    NASA Astrophysics Data System (ADS)

    Yang, M.; Blomquist, B.; Beale, R.; Nightingale, P. D.; Liss, P. S.

    2015-12-01

    Atmospheric volatile organic compounds (VOCs) affect the tropospheric oxidative capacity due to their ubiquitous abundance and relatively high reactivity towards the hydroxyal radical. Over the ocean and away from terrestrial emission sources, oxygenated volatile organic compounds (OVOCs) make up a large fraction of VOCs as airmasses age and become more oxidized. In addition to being produced or destroyed in the marine atmosphere, OVOCs can also be emitted from or deposited to the surface ocean. Here we first present direct air-sea flux measurements of three of the most abundant OVOCs - methanol, acetone, and acetaldehyde, by the eddy covariance technique from two cruises in the Atlantic: the Atlantic Meridional Transect in 2012 and the High Wind Gas Exchange Study in 2013. The OVOC mixing ratios were quantified by a high resolution proton-reaction-transfer mass spectrometer with isotopically labeled standards and their air-sea (net) fluxes were derived from the eddy covariance technique. Net methanol flux was consistently from the atmosphere to the surface ocean, while acetone varied from supersaturation (emission) in the subtropics to undersaturation (deposition) in the higher latitudes of the North Atlantic. The net air-sea flux of acetaldehyde is near zero through out the Atlantic despite the apparent supersaturation of this compound in the surface ocean. Knowing the dissolved concentrations and in situ production rates of these compounds in seawater, we then estimate their bulk atmospheric depositions and oceanic emissions. Lastly, we summarize the state of knowledge on the air-sea transport of a number of organic gasses, and postulate the magnitude and environmental impact of total organic carbon transfer between the ocean and the atmosphere.

  19. Atmospheric Emissions Photometric Imaging Experiment For Spacelab 1

    NASA Astrophysics Data System (ADS)

    Sandie, William G.; Mende, Stephen B.; Swenson, Gary R.; Polites, Michael E.

    1983-12-01

    The atmospheric emissions photometric imaging (AEPI) experiment to be flown on Spacelab 1 is designed to study faint natural and artificial atmospheric emission phenomena. Atmospheric emissions in the spectral region 2000 A to 7500 A from two optical channels, wide angle and telephoto, are detected by an image-enhanced low-light-level TV system. A third, telephoto, optical channel images onto the photocathode of a microchannel plate photomultiplier tube having 100 discrete anodes. Photons are counted for each discrete anode, providing a direct measure of the luminosity of an object viewed by the TV telephoto lens, albeit with low spatial resolution. Detector pointing in the range +/-40°x+/-80°exclusive of restrictions due to the proximity of other experiments is provided by a two-axis gimbal made from a surplus Apollo telescope mount (MAST). The pointing stability is 1 arc min with respect to the spacecraft coordinate system for an exposure of one s, and the tracking capability is 3.5 deg - s-1 with a stability of 1 arc min. The detector and pointing system are located on the Spacelab pallet and are controlled by stored programs resident in the dedicated experiment processor located in the Spacelab module.

  20. Atmospheric emission of NOx from mining explosives: A critical review

    NASA Astrophysics Data System (ADS)

    Oluwoye, Ibukun; Dlugogorski, Bogdan Z.; Gore, Jeff; Oskierski, Hans C.; Altarawneh, Mohammednoor

    2017-10-01

    High-energy materials such as emulsions, slurries and ammonium-nitrate fuel-oil (ANFO) explosives play crucial roles in mining, quarrying, tunnelling and many other infrastructure activities, because of their excellent transport and blasting properties. These explosives engender environmental concerns, due to atmospheric pollution caused by emission of dust and nitrogen oxides (NOx) from blasts, the latter characterised by the average emission factor of 5 kg (t AN explosive)-1. This first-of-its-kind review provides a concise literature account of the formation of NOx during blasting of AN-based explosives, employed in surface operations. We estimate the total NOx emission rate from AN-based explosives as 0.05 Tg (i.e., 5 × 104 t) N per annum, compared to the total global annual anthropogenic NOx emissions of 41.3 × 106 t N y-1. Although minor in the global sense, the large localised plumes from blasting exhibit high NOx concentration (500 ppm) exceeding up to 3000 times the international standards. This emission has profound consequences at mining sites and for adjacent atmospheric environment, necessitating expensive management of exclusion zones. The review describes different types of AN energetic materials for civilian applications, and summarises the essential properties and terminologies pertaining to their use. Furthermore, we recapitulate the mechanisms that lead to the formation of the reactive nitrogen species in blasting of AN-based explosives, review their implications to atmospheric air pollution, and compare the mechanisms with those experienced in other thermal and combustion operations. We also examine the mitigation approaches, including guidelines and operational-control measures. The review discusses the abatement technologies such as the formulation of new explosive mixtures, comprising secondary fuels, spin traps and other additives, in light of their effectiveness and efficiency. We conclude the review with a summary of unresolved problems

  1. Pulsed, atmospheric pressure plasma source for emission spectrometry

    DOEpatents

    Duan, Yixiang; Jin, Zhe; Su, Yongxuan

    2004-05-11

    A low-power, plasma source-based, portable molecular light emission generator/detector employing an atmospheric pressure pulsed-plasma for molecular fragmentation and excitation is described. The average power required for the operation of the plasma is between 0.02 W and 5 W. The features of the optical emission spectra obtained with the pulsed plasma source are significantly different from those obtained with direct current (dc) discharge higher power; for example, strong CH emission at 431.2 nm which is only weakly observed with dc plasma sources was observed, and the intense CN emission observed at 383-388 nm using dc plasma sources was weak in most cases. Strong CN emission was only observed using the present apparatus when compounds containing nitrogen, such as aniline were employed as samples. The present apparatus detects dimethylsulfoxide at 200 ppb using helium as the plasma gas by observing the emission band of the CH radical. When coupled with a gas chromatograph for separating components present in a sample to be analyzed, the present invention provides an apparatus for detecting the arrival of a particular component in the sample at the end of the chromatographic column and the identity thereof.

  2. Australian HFC, PFC and SF6 emissions: atmospheric verification

    NASA Astrophysics Data System (ADS)

    Fraser, P.; Dunse, B.; Krummel, P. B.; Steele, P.; Manning, A. J.

    2011-12-01

    The synthetic greenhouse gases (GHGs: hydrofluorocarbons - HFCs, perfluorocarbons - PFCs, and sulfur hexafluoride - SF6), emitted largely by the refrigeration, aluminium and electricity distribution industries respectively, are currently responsible for less than 2% of Australia's net long-lived GHG emissions (DCCEE, 2011). Nevertheless, they have attracted the attention of policymakers because (1) if their growth in concentrations and emissions continues unabated, particularly HFCs - currently growing at 10% per year - then they could be responsible globally (and in Australia) for more than 10% of the radiative forcing due to long-lived GHGs by 2050 (Velders et al., 2009); and (2) they provide the opportunity for a very cost-effective GHG mitigation strategy, because emissions can be reduced significantly through better engineering to minimize emissions, through a ban on dispersive uses (as solvents for example) and through the use of low GWP (Global Warming Potential) alternatives (for example hydrofluoroethers - HFEs). CSIRO, through its involvement in the AGAGE global program of monitoring non-carbon dioxide GHGs (Prinn et al., 2000), has been making high precision in situ measurements (12 per day) of HFCs, PFCs and SF6 at Cape Grim, Tasmania, since 2004, using a gas chromatograph-mass spectrometer detector (GC-MSD) fitted with a custom-built cryo-focussing unit (Medusa: Miller et al., 2008). The resultant data have been used to derive Australian emissions by inverse modelling (NAME, TAPM) and interspecies correlation (ISC). The overall agreement between so-called bottom-up estimates of Australian emissions, as reported to the UNFCCC (United Nations Framework Convention on Climate Change), and top-down estimates from atmospheric observations, using NAME, TAPM and ISC, is encouraging. Australian UNFCCC reported emissions (DCCEE, 2011) generally agree to within of 10% of emissions calculated from Cape Grim data, scaled on a population basis, with some notable

  3. Methane emissions to the atmosphere through aquatic plants

    NASA Technical Reports Server (NTRS)

    Sebacher, D. I.; Harriss, R. C.; Bartlett, K. B.

    1985-01-01

    The movement of methane (CH4) from anaerobic sediments through the leaves, stems, and flowers of aquatic plants and into the atmosphere was found to provide a significant pathway for the emission of CH4 from the aquatic substrates of flooded wetlands. Methane concentrations well above the surrounding ambient air levels were found in the mesophyll of 16 varies of aquatic plants and are attributed to transpiration, diffusion, and pressure-induced flow of gaseous CH4 from the roots when they are embedded in CH4-saturated anaerobic sediments. Methane emissions from the emergent parts of aquatic plants were measured using floating chamber techniques and by enclosing the plants in polyethylene bags of known volume. Concentration changes were monitored in the trapped air using syringes and gas chromatographic techniques. Vertical profiles of dissolved CH4 in sediment pore water surrounding the aquatic plants' rhizomes were obtained using an interstitial sampling technique. Methane emissions from the aquatic plants studied varied from 14.8 mg CH4/d to levels too low to be detectable. Rooted and unrooted freshwater aquatic plants were studied as well as saltwater and brackish water plants. Included in the experiment is detailed set of measurements on CH4 emissions from the common cattail (Typha latifolia). This paper illustrates that aquatic plants play an important gas exchange role in the C cycle between wetlands and the atmosphere.

  4. Methane emissions to the atmosphere through aquatic plants

    NASA Technical Reports Server (NTRS)

    Sebacher, D. I.; Harriss, R. C.; Bartlett, K. B.

    1985-01-01

    The movement of methane (CH4) from anaerobic sediments through the leaves, stems, and flowers of aquatic plants and into the atmosphere was found to provide a significant pathway for the emission of CH4 from the aquatic substrates of flooded wetlands. Methane concentrations well above the surrounding ambient air levels were found in the mesophyll of 16 varies of aquatic plants and are attributed to transpiration, diffusion, and pressure-induced flow of gaseous CH4 from the roots when they are embedded in CH4-saturated anaerobic sediments. Methane emissions from the emergent parts of aquatic plants were measured using floating chamber techniques and by enclosing the plants in polyethylene bags of known volume. Concentration changes were monitored in the trapped air using syringes and gas chromatographic techniques. Vertical profiles of dissolved CH4 in sediment pore water surrounding the aquatic plants' rhizomes were obtained using an interstitial sampling technique. Methane emissions from the aquatic plants studied varied from 14.8 mg CH4/d to levels too low to be detectable. Rooted and unrooted freshwater aquatic plants were studied as well as saltwater and brackish water plants. Included in the experiment is detailed set of measurements on CH4 emissions from the common cattail (Typha latifolia). This paper illustrates that aquatic plants play an important gas exchange role in the C cycle between wetlands and the atmosphere.

  5. Regional differences in worldwide emissions of mercury to the atmosphere

    NASA Astrophysics Data System (ADS)

    Pirrone, Nicola; Keeler, Gerald J.; Nriagu, Jerome O.

    Annual emissions of anthropogenic Hg to the atmosphere in different regions of the world during the last decade show an interesting dichotomy: the emissions in the developed countries increased at the rate of about 4.5-5.5% yr -1 up to 1989 and have since remained nearly constant, while in developing countries the emissions continue to rise steadily at the rate of 2.7-4.5% yr -1. On a global basis, however, the total anthropogenic emissions of Hg increased by about 4% yr -1 during the 1980s, peaked in 1989 at about 2290 t and are currently decreasing at the rate of about 1.3% yr -1. Solid waste disposal through incineration processes is the dominant source of atmospheric mercury in North America (˜ 40%), Central and South America (˜34%), western Europe (˜28%) and Africa (˜30%), whereas coal combustion remains the dominant source in Asia (˜42%) and eastern Europe and the former USSR (˜40%). Mining and smelting of Zn and Pb represent the major industrial source of Hg in Oceania (˜35%).

  6. Non-LTE line-blanketed model atmospheres of hot stars. 2: Hot, metal-rich white dwarfs

    NASA Technical Reports Server (NTRS)

    Lanz, T.; Hubeny, I.

    1995-01-01

    We present several model atmospheres for a typical hot metal-rich DA white dwarf, T(sub eff) = 60,000 K, log g = 7.5. We consider pure hydrogen models, as well as models with various abundances of two typical 'trace' elements-carbon and iron. We calculte a number of Local Thermodynamic Equilibrium (LTE) and non-LTE models, taking into account the effect of numerous lines of these elements on the atmospheric structure. We demostrate that while the non-LTE effects are notvery significant for pure hydrogen models, except for describing correctly the central emission in H-alpha they are essential for predicting correctly the ionization balance of metals, such as carbon and iron. Previously reported discrepancies in LTE abundances determinations using C III and C IV lines are easily explained by non-LTE effects. We show that if the iron abundance is larger than 10(exp -5), the iron line opacity has to be considered not only for the spectrum synthesis, but also in the model construction itself. For such metal abundances, non-LTE metal line-blanketed models are needed for detailed abundance studies of hot, metal-rich white dwarfs. We also discuss the predicted Extreme Ultraviolet (EUV) spectrum and show that it is very sensitive to metal abundances, as well as to non-LTE effects.

  7. Non-LTE line-blanketed model atmospheres of hot stars. 2: Hot, metal-rich white dwarfs

    NASA Technical Reports Server (NTRS)

    Lanz, T.; Hubeny, I.

    1995-01-01

    We present several model atmospheres for a typical hot metal-rich DA white dwarf, T(sub eff) = 60,000 K, log g = 7.5. We consider pure hydrogen models, as well as models with various abundances of two typical 'trace' elements-carbon and iron. We calculte a number of Local Thermodynamic Equilibrium (LTE) and non-LTE models, taking into account the effect of numerous lines of these elements on the atmospheric structure. We demostrate that while the non-LTE effects are notvery significant for pure hydrogen models, except for describing correctly the central emission in H-alpha they are essential for predicting correctly the ionization balance of metals, such as carbon and iron. Previously reported discrepancies in LTE abundances determinations using C III and C IV lines are easily explained by non-LTE effects. We show that if the iron abundance is larger than 10(exp -5), the iron line opacity has to be considered not only for the spectrum synthesis, but also in the model construction itself. For such metal abundances, non-LTE metal line-blanketed models are needed for detailed abundance studies of hot, metal-rich white dwarfs. We also discuss the predicted Extreme Ultraviolet (EUV) spectrum and show that it is very sensitive to metal abundances, as well as to non-LTE effects.

  8. Anchoring Atmospheric Density Models Using Observed Shuttle Plume Emissions

    NASA Astrophysics Data System (ADS)

    Dimpfl, W. L.; Bernstien, L. S.

    2010-12-01

    Atmospheric number densities at a given low-earth orbit (LEO) altitude can vary by more than an order of magnitude, depending on such parameters as diurnal variations and solar activity. The MSIS atmospheric model, which includes these dependent variables as input, is reported as being accurate to ±15%. Improvement to such models requires accurate direct atmospheric measurement. Here, a means of anchoring atmospheric models is offered through measuring the size and shape of atomic line or molecular band radiance resulting from the atmospheric interaction from rocket engine plumes or gas releases in LEO. Many discrete line or band emissions, ranging from the infrared to the ultraviolet may be suitable. For this purpose we are focusing on NH(A→X), centered at 316 nm. This emission is seen in the plumes of the Shuttle Orbiter PRCS engines, is expected in the plume of any amine fueled engine, and can be observed from remote sensors in space or on the ground. The atmospheric interaction of gas releases or plumes from spacecraft in LEO are understood by comparison of observed radiance with that predicted by Direct Simulation Monte Carlo (DSMC) models. The recent Extended Variable Hard Sphere (EVHS) improvements in treating hyperthermal collisions has produced exceptional agreement between measured and modeled steady-state Space Shuttle OMS and PRCS 190-250 nm Cameron band plume radiance from CO(a→X), which is understood to result from a combination of two- and three-step mechanisms. Radiance from NH(A→X) in far field plumes is understood to result from a simpler single-step process of the reaction of a minor plume species with atomic oxygen, making it more suitable for use in determining atmospheric density. It is recommended that direct retrofire burns of amine fueled engines be imaged in a narrow band from remote sensors to reveal atmospheric number density. In principal the simple measurement of the distance between the engine exit and the peak in the steady

  9. Atmospheric Pollution and Emission Sources in South Asian Urban Region

    NASA Astrophysics Data System (ADS)

    Biswas, K. F.; Husain, Liaquat

    2009-04-01

    Rapid urbanization, and lack of efficient monitoring and control of pollution, along with phenomena like Asian Brown Haze or prolonged episodes of winter fog, makes the South Asian atmospheric chemistry a very complex one. The anthropogenic aerosols released from this region are projected to become the dominant component of anthropogenic aerosols worldwide in the next 25 years (Nakicenovic and Swart, 2000). The region is one of the most densely populated in the world, with present population densities of 100-500 persons km-2. There are six big cities, namely, Delhi, Dhaka, Karachi, Kolkata, Lahore, and Mumbai, each housing a population around or above 10 million. There is now a real concern about the sustainability of the region's ability to support the population due to air pollution, loss of biodiversity and soil degradation. Therefore, we conducted several extensive campaigns over last 10 years in Lahore, Karachi, and Islamabad in Pakistan to (1) chemically characterize the aerosols (PM2.5 mass, concentrations of trace elements, ions, black and organic carbon), and gaseous pollutants (concentrations of NH3, SO2, HONO, HNO3, HCl and (COOH)2, and (2) identify the major emission sources in this region. Exceedingly high concentrations of all species, relative to major urban areas of US and Europe, were observed. Concentrations of PM2.5, BC, Pb, SO42-, NH4+, HONO, NH3 respectively, up to 476, 110, 12, 66, 60, 19.6 and 50 μgm-3 were observed in these cities, which were far in excess of WHO and US EPA air quality standard (Biswas et al., 2008). We use air parcel back trajectories, intercomponent relationships and meteorological observations to explain chemistry and emission sources of aerosol constituents. Carbonaceous aerosols contributed up to 69% of the PM2.5 mass (Husain et al., 2007). Source apportionment was conducted using positive matrix factorization. The analysis has classified six emission sources of aerosol components, namely, industrial activities, wood

  10. Infrared Observations of SO emission from Io's Atmosphere during Eclipse

    NASA Astrophysics Data System (ADS)

    de Kleer, K.; De Pater, I.; Adamkovics, M.

    2013-12-01

    Io, the volcanic moon of Jupiter, hosts an atmosphere dominated by SO2 and SO, but the question of the direct source of these molecules is still debated. Many different approaches have been taken to establish a link between volcanic activity on Io and atmospheric effects, to distinguish whether the atmosphere is supplied by volcanic outgassing or ice sublimation. In the infrared, atmospheric emission lines are lost in reflected sunlight; observing Io in eclipse provides a unique opportunity to study infrared lines, during a time when most of Io's atmosphere may be frozen out in Jupiter's shadow. In 1999 the a1Δ → Χ3Σ- transition of SO at 1.707 μm was discovered by de Pater et al. (2002); Laver et al. (2007) made additional observations, which they fit with equilibrium models to infer a likely volcanic origin for the SO. Here we present additional high spectral resolution observations of the 1.707 μm SO line while Io is in eclipse. We model these observations with equilibrium and non-LTE models, and address implications for the origin of SO on Io.

  11. Characterization of Coal Ash Emissivity in High Temperature Atmospheres

    NASA Astrophysics Data System (ADS)

    Shimogori, Miki; Yoshizako, Hidehisa; Shimogori, Yoshio; Richardson, Mark

    This paper presents a method for determining coal ash emissivity in high temperature atmospheres. We applied a tube-dropping mechanism to suppress reflection from the sample, and tried other new approaches for measurements at high temperatures. One approach was a shielding time reduction using tube motorization, which reduces measurement errors to a negligible level. Another approach was determining emissivity by fitting a calculation curve to transient experimental data. In these calculations, adjustable parameters were emissivity and thermal conductivity. An ash sample was heated in an electric furnace in the range from 500 to 1300°C and the radiation intensity from the sample was measured with a digital pyrometer. Each measurement was carried out within 0.3 seconds, including the time required for shielding the sample (0.1 seconds). Once the tube had been dropped into the furnace, radiation intensities from the sample began decreasing. Emissivity characteristics were compared between Powder River Basin (PRB) coal ash and bituminous coal ash. It was found that coal-ash emissivity depends on coal types and changes significantly as a function of ash surface temperature.

  12. Methane Emissions from the Arctic Ocean to the Atmosphere

    NASA Astrophysics Data System (ADS)

    Platt, Stephen; Hermansen, Ova; Schmidbauer, Norbert; Pisso, Ignacio; Silyakova, Anna; Ferré, Benedicte; Lowry, Dave; Percival, Carl; Mienert, Jürgen; Myhre, Cathrine Lund

    2015-04-01

    The release of methane (CH4) presently stored in vast hydrate deposits under the seafloor is a potential climate tipping point and a major uncertainty in the global methane budget. Significant methane hydrate deposits are located in shallow waters in the Arctic where they may destabilise, releasing methane to the atmosphere due to ocean warming. To address this issue the Methane Emissions from Arctic Ocean to Atmosphere (MOCA, http://moca.nilu.no/) project was established in cooperation with the CAGE Centre of Excellence (http:cage.uit.no/). State-of-the-art oceanographic and atmospheric measurement techniques were applied over a large area of the Arctic including northern Norway, the Barents Sea, and areas of shallow water around Svalbard during summer 2014. Oceanographic measurements included the deployment of 63 measurement stations (temperature, salinity, density, oxygen, fluorescence, turbidity, etc.), water column sampling (CH4, nitrate, phosphate, silicates), and echo sounding (revealing locations where streams of gas bubbles are vented). Atmospheric on-line measurements were performed aboard the research vessel Helmer Hanssen (CH4, CO2, CO, meteorological parameters) and during a flight campaign (CH4, etc.). Air samples were collected for isotopic analysis (13C, 2H) and quantification of other hydrocarbons (ethane, propane, etc.). Finally, atmospheric measurements are compared with long term data sets from the nearby Zeppelin Mountain monitoring station (Ny Ålesund, Svalbard). Back-trajectory analysis and FLEXPART modelling are used to rule out non-local sources. Here we present an overview of all of these activities and the first results from MOCA in cooperation with CAGE - Centre for Arctic Gas Hydrate, and Climate at UiT, The Arctic University of Norway. We demonstrate that there are hotspots of activity where hydrocarbons are being emitted from the ocean, while in some areas emissions are surprisingly well contained by local biological and hydrological

  13. Modeling study of natural emissions, source apportionment, and emission control of atmospheric mercury

    NASA Astrophysics Data System (ADS)

    Shetty, Suraj K.

    Mercury (Hg) is a toxic pollutant and is important to understand its cycling in the environment. In this dissertation, a number of modeling investigations were conducted to better understand the emission from natural surfaces, the source-receptor relationship of the emissions, and emission reduction of atmospheric mercury. The first part of this work estimates mercury emissions from vegetation, soil and water surfaces using a number of natural emission processors and detailed (LAI) Leaf Area Index data from GIS (Geographic Information System) satellite products. East Asian domain was chosen as it contributes nearly 50% of the global anthropogenic mercury emissions into the atmosphere. The estimated annual natural mercury emissions (gaseous elemental mercury) in the domain are 834 Mg yr-1 with 462 Mg yr-1 contributing from China. Compared to anthropogenic sources, natural sources show greater seasonal variability (highest in simmer). The emissions are significant, sometimes dominant, contributors to total mercury emission in the regions. The estimates provide possible explanation for the gaps between the anthropogenic emission estimates based on activity data and the emission inferred from field observations in the regions. To understand the contribution of domestic emissions to mercury deposition in the United States, the second part of the work applies the mercury model of Community Multi-scale Air Quality Modeling system (CMAQ-Hg v4.6) to apportion the various emission sources attributing to the mercury wet and dry deposition in the 6 United States receptor regions. Contributions to mercury deposition from electric generating units (EGU), iron and steel industry (IRST), industrial point sources excluding EGU and IRST (OIPM), the remaining anthropogenic sources (RA), natural processes (NAT), and out-of-boundary transport (BC) in domain was estimated. The model results for 2005 compared reasonably well to field observations made by MDN (Mercury Deposition Network

  14. Atmospheric emissions photometric imaging experiment /AEPT/ for Spacelab 1

    NASA Astrophysics Data System (ADS)

    Sandie, W. G.; Mende, S. B.; Swenson, G. R.; Polites, M. E.

    1981-04-01

    The atmospheric emissions photometric imaging experiment (AEPI) to be flown on Spacelab 1 is designed to study faint natural and artificial atmospheric emission phenomena. Optical emissions are imaged in the region 2150 A to 7320 A using a television system consisting of two optical channels, one wide-angle and one telephoto. The detection system is an image-enhanced SEC vidicon. A third optical channel images onto the photocathode of a microchannel plate photomultiplier tube that has 100 discrete anodes. Photons are counted for each discrete anode, providing a direct measure of the luminosity of an object viewed by the TV telephoto lens, albeit with low spatial resolution. The AEPI detector is mounted on a two-axis gimbal comprised of a Modified Apollo Telescope Mount Star Tracker (MAST), which provides experiment pointing over a 40-deg x 80-deg range, exclusive of restrictions due to the proximity of other experiments. The pointing stability is 1 arcmin with respect to the spacecraft coordinate system for an exposure of 1 second. The tracking capability is 3.5 deg/s with a stability of 1 arcmin. The detector and pointing system are located on the Spacelab pallet. The experiment is controlled by stored programs resident in the Dedicated Experiment Processor located in the Spacelab module.

  15. Osmium isotopic tracing of atmospheric emissions from an aluminum smelter

    NASA Astrophysics Data System (ADS)

    Gogot, Julien; Poirier, André; Boullemant, Amiel

    2015-09-01

    We present for the first time the use of osmium isotopic composition as a tracer of atmospheric emissions from an aluminum smelter, where alumina (extracted from bauxite) is reduced through electrolysis into metallic aluminum using carbonaceous anodes. These anodes are consumed in the process; they are made of petroleum coke and pitch and have high Re/Os elementary ratio. Due to the relatively large geological age of their source material, their osmium shows a high content of radiogenic 187Os produced from in situ187Re radioactive decay. The radiogenic isotopic composition (187Os/188Os ∼ 2.5) of atmospheric particulate emissions from this smelter is different from that of other typical anthropogenic osmium sources (that come from ultramafic geological contexts with unradiogenic Os isotopes, e.g., 187Os/188Os < 0.2) and also different from average eroding continental crust 187Os/188Os ratios (ca. 1.2). This study demonstrates the capacity of osmium measurements to monitor particulate matter emissions from the Al-producing industry.

  16. Deciphering the atmospheric composition of WASP-12b: A comprehensive analysis of its dayside emission

    SciTech Connect

    Stevenson, Kevin B.; Bean, Jacob L.; Madhusudhan, Nikku; Harrington, Joseph

    2014-08-10

    WASP-12b was the first planet reported to have a carbon-to-oxygen ratio (C/O) greater than one in its dayside atmosphere. However, recent work to further characterize its atmosphere and confirm its composition has led to incompatible measurements and divergent conclusions. Additionally, the recent discovery of stellar binary companions ∼1'' from WASP-12 further complicates the analyses and subsequent interpretations. We present a uniform analysis of all available Hubble and Spitzer Space Telescope secondary-eclipse data, including previously unpublished Spitzer measurements at 3.6 and 4.5 μm. The primary controversy in the literature has centered on the value and interpretation of the eclipse depth at 4.5 μm. Our new measurements and analyses confirm the shallow eclipse depth in this channel, as first reported by Campo and collaborators and used by Madhusudhan and collaborators to infer a carbon-rich composition. To explain WASP-12b's observed dayside emission spectrum, we implemented several recent retrieval approaches. We find that when we exclude absorption due to C{sub 2}H{sub 2} and HCN, which are not universally considered in the literature, our models require implausibly large atmospheric CO{sub 2} abundances, regardless of the C/O. By including C{sub 2}H{sub 2} and HCN in our models, we find that a physically plausible carbon-rich solution achieves the best fit to the available photometric and spectroscopic data. In comparison, the best-fit oxygen-rich models have abundances that are inconsistent with the chemical equilibrium expectations for hydrogen-dominated atmospheres and are 670 times less probable. Our best-fit solution is also 7.3 × 10{sup 6} times more probable than an isothermal blackbody model.

  17. Water loss from terrestrial planets with CO{sub 2}-rich atmospheres

    SciTech Connect

    Wordsworth, R. D.; Pierrehumbert, R. T.

    2013-12-01

    Water photolysis and hydrogen loss from the upper atmospheres of terrestrial planets is of fundamental importance to climate evolution but remains poorly understood in general. Here we present a range of calculations we performed to study the dependence of water loss rates from terrestrial planets on a range of atmospheric and external parameters. We show that CO{sub 2} can only cause significant water loss by increasing surface temperatures over a narrow range of conditions, with cooling of the middle and upper atmosphere acting as a bottleneck on escape in other circumstances. Around G-stars, efficient loss only occurs on planets with intermediate CO{sub 2} atmospheric partial pressures (0.1-1 bar) that receive a net flux close to the critical runaway greenhouse limit. Because G-star total luminosity increases with time but X-ray and ultraviolet/ultravoilet luminosity decreases, this places strong limits on water loss for planets like Earth. In contrast, for a CO{sub 2}-rich early Venus, diffusion limits on water loss are only important if clouds caused strong cooling, implying that scenarios where the planet never had surface liquid water are indeed plausible. Around M-stars, water loss is primarily a function of orbital distance, with planets that absorb less flux than ∼270 W m{sup –2} (global mean) unlikely to lose more than one Earth ocean of H{sub 2}O over their lifetimes unless they lose all their atmospheric N{sub 2}/CO{sub 2} early on. Because of the variability of H{sub 2}O delivery during accretion, our results suggest that many 'Earth-like' exoplanets in the habitable zone may have ocean-covered surfaces, stable CO{sub 2}/H{sub 2}O-rich atmospheres, and high mean surface temperatures.

  18. Atmospheric Impact of Large Methane Emission in the Arctic Region

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, S.; Cameron-Smith, P. J.; Bergmann, D.; Reagan, M. T.; Collins, W.; Elliott, S. M.; Maltrud, M. E.

    2011-12-01

    A highly potent greenhouse gas, methane, is locked in the solid phase as ice-like deposits containing a mixture of water and gas (mostly methane) called clathrates, in ocean sediments and underneath permafrost regions. Clathrates are stable under high pressure and low temperatures. Recent estimates suggest that about 1600 - 2000GtC of clathrates are present in oceans and 400GtC in Arctic permafrost (Archer et al.2009) which is about 4000 times that of current annual emissions. In a warming climate, increase in ocean temperatures could alter the geothermal gradient, which in turn could lead to dissociation of the clathrates and release of methane into the ocean and subsequently into the atmosphere as well. This could be of particular importance in the shallow part of the Arctic Ocean where the clathrates are found in depths of only 300m. In this presentation, we shall show results from our ongoing simulation of a scenario of large scale methane outgassing from clathrate dissociation due to warming ocean temperatures in the Arctic based on ocean sediment modeling. To that end we use the CESM (Community Earth System Model) version 1 with fully active coupled atmosphere-ocean-land model together with fast atmospheric chemistry module to simulate the response to increasing methane emissions in the Barents Sea, Canadian Archipelago and the Sea of Okhotsk. The simulation shows the effect these methane emissions could have on global surface methane, surface ozone, surface air temperature and other related indices. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-491764

  19. Wide angle Michelson Doppler imaging interferometer. [measuring atmospheric emissions

    NASA Technical Reports Server (NTRS)

    Shepherd, G. G.

    1980-01-01

    The optical system, stepping control, phase and modulation depth, array detector, and directions sensor are described for a specialized type of Michelson interferometer which works at sufficiently high resolution to measure the line widths and Doppler shifts of naturally occurring atmospheric emissions. With its imaging capability, the instrument can potentially supply this data independently for each element of the 100 x 100 detector array. The experiment seeks: (1) to obtain vertical profiles of atmospheric winds and temperatures as functions of latitude by observing near the limb; (2) to acquire exploratory wind and temperature data on smaller scale structures in airglow irregularities and in auroral forms; and (3) to collaborate with other Spacelab experiments, such as barium cloud releases, in providing wind and temperature data.

  20. Micrometeroid Flight in the Upper Atmosphere: Electron Emission and Charging

    NASA Astrophysics Data System (ADS)

    Mendis, A.; Rosenberg, M.; Wong, W.; Sorasio, G.

    2003-12-01

    Solving the simultaneous equations for the continuity of charge, mass, momentum and energy of a micrometeoroid entering the earth's atmosphere, we study its charging, ablation, deceleration and heating along its path. This analysis, which considers different initial entry speeds and angles, builds on an earlier study (G. Sorasio, D. A. Mendis and M. Rosenberg, 2001, Planet. Space Sci., 49, 1257) where only normal entry at a single speed was considered, while emphasizing the important role of thermionic emission of electrons from the frictionally heated micrometeoroid. While the main conclusions are qualitatively similar, the quantitative differences are significant. As before the micrometeoroid can change its charge polarity during flight and the altitude range of meteoric ionization is larger than in the case when ionization is due only to collisions between sublimating molecules and background atmospheric molecules. However, the present study shows that this range becomes larger, with earlier onset of ionization, as the initial entry speed becomes larger and the initial entry angle becomes smaller. Interestingly we also find that the residual mass of the ablated micrometeoroid is a minimum at a certain critical angle of entry, for a given initial speed. The implications of this study for atmospheric ionization by different meteor streams, as well as for radar observations of meteors (e.g., the head and trail echoes) will be discussed. The implications of this study for atmospheric ionization by different meteor streams, as well as for radar observations of meteors (e.g., the head and trail echoes) will be discussed.

  1. Atmospheric emission of reactive nitrogen during biofuel ethanol production.

    PubMed

    Machado, Cristine M D; Cardoso, Arnaldo A; Allen, Andrew G

    2008-01-15

    This paper evaluates emissions to the atmosphere of biologically available nitrogen compounds in a region characterized by intensive sugar cane biofuel ethanol production. Large emissions of NH3 and NOx, as well as particulate nitrate and ammonium, occur at the harvest when the crop is burned, with the amount of nitrogen released equivalent to approximately 35% of annual fertilizer-N application. Nitrogen oxides concentrations show a positive association with fire frequency, indicating that biomass burning is a major emission source, with mean concentrations of NOx doubling in the dry season relative to the wetseason. During the dry season biomass burning is a source of NH3, with other sources (wastes, soil, biogenic) predominant during the wet season. Estimated NO2-N, NH3-N, NO3- -N and NH4+ -N emission fluxes from sugar cane burning in a planted area of ca. 2.2 x 10(6) ha are 11.0, 1.1, 0.2, and 1.2 Gg N yr(-1), respectively.

  2. Nitrogen speciation in upper mantle fluids and the origin of Earth's nitrogen-rich atmosphere

    NASA Astrophysics Data System (ADS)

    Mikhail, Sami; Sverjensky, Dimitri A.

    2014-11-01

    Volatile elements stored in the mantles of terrestrial planets escape through volcanic degassing, and thereby influence planetary atmospheric evolution and habitability. Compared with the atmospheres of Venus and Mars, Earth's atmosphere is nitrogen-rich relative to primordial noble gas concentrations. The compatibility of volatile elements in mantle minerals versus melts and fluids controls how readily these elements are degassed. However, the speciation of nitrogen in mantle fluids is not well constrained. Here we present thermodynamic calculations that establish the speciation of nitrogen in aqueous fluids under upper mantle conditions. We find that, under the relatively oxidized conditions of Earth's mantle wedges at convergent plate margins, nitrogen is expected to exist predominantly as N2 in fluids and, therefore, be degassed easily. In contrast, under more reducing conditions elsewhere in the Earth's upper mantle and in the mantles of Venus and Mars, nitrogen is expected predominantly in the form of ammonium (NH4+) in aqueous fluids. Ammonium is moderately compatible in upper mantle minerals and unconducive to nitrogen degassing. We conclude that Earth's oxidized mantle wedge conditions--a result of subduction and hence plate tectonics--favour the development of a nitrogen-enriched atmosphere, relative to the primordial noble gases, whereas the atmospheres of Venus and Mars have less nitrogen because they lack plate tectonics.

  3. CO2 and CH4 emissions from streams in a lake-rich landscape: Patterns, controls, and regional significance

    NASA Astrophysics Data System (ADS)

    Crawford, John T.; Lottig, Noah R.; Stanley, Emily H.; Walker, John F.; Hanson, Paul C.; Finlay, Jacques C.; Striegl, Robert G.

    2014-03-01

    Aquatic ecosystems are important components of landscape carbon budgets. In lake-rich landscapes, both lakes and streams may be important sources of carbon gases (CO2 and CH4) to the atmosphere, but the processes that control gas concentrations and emissions in these interconnected landscapes have not been adequately addressed. We use multiple data sets that vary in their spatial and temporal extent during 2001-2012 to investigate the carbon gas source strength of streams in a lake-rich landscape and to determine the contribution of lakes, metabolism, and groundwater to stream CO2 and CH4. We show that streams emit roughly the same mass of CO2 (23.4 Gg C yr-1; 0.49 mol CO2 m-2 d-1) as lakes at a regional scale (27 Gg C yr-1) and that stream CH4 emissions (189 Mg C yr-1; 8.46 mmol CH4 m-2 d-1) are an important component of the regional greenhouse gas balance. Gas transfer velocity variability (range = 0.34 to 13.5 m d-1) contributed to the variability of gas flux in this landscape. Groundwater inputs and in-stream metabolism control stream gas supersaturation at the landscape scale, while carbon cycling in lakes and deep groundwaters does not control downstream gas emissions. Our results indicate the need to consider connectivity of all aquatic ecosystems (lakes, streams, wetlands, and groundwater) in lake-rich landscapes and their connections with the terrestrial environment in order to understand the full nature of the carbon cycle.

  4. CO2 and CH4 emissions from streams in a lake-rich landscape: Patterns, controls, and regional significance

    USGS Publications Warehouse

    Crawford, John T.; Lottig, Noah R.; Stanley, Emily H.; Walker, John F.; Hanson, Paul C.; Finlay, Jacques C.; Striegl, Robert G.

    2014-01-01

    Aquatic ecosystems are important components of landscape carbon budgets. In lake-rich landscapes, both lakes and streams may be important sources of carbon gases (CO2 and CH4) to the atmosphere, but the processes that control gas concentrations and emissions in these interconnected landscapes have not been adequately addressed. We use multiple data sets that vary in their spatial and temporal extent during 2001–2012 to investigate the carbon gas source strength of streams in a lake-rich landscape and to determine the contribution of lakes, metabolism, and groundwater to stream CO2 and CH4. We show that streams emit roughly the same mass of CO2 (23.4 Gg C yr−1; 0.49 mol CO2 m−2 d−1) as lakes at a regional scale (27 Gg C yr−1) and that stream CH4 emissions (189 Mg C yr−1; 8.46 mmol CH4 m−2 d−1) are an important component of the regional greenhouse gas balance. Gas transfer velocity variability (range = 0.34 to 13.5 m d−1) contributed to the variability of gas flux in this landscape. Groundwater inputs and in-stream metabolism control stream gas supersaturation at the landscape scale, while carbon cycling in lakes and deep groundwaters does not control downstream gas emissions. Our results indicate the need to consider connectivity of all aquatic ecosystems (lakes, streams, wetlands, and groundwater) in lake-rich landscapes and their connections with the terrestrial environment in order to understand the full nature of the carbon cycle.

  5. Contribution of the atmospheric emissions of Spanish ceramics industries

    NASA Astrophysics Data System (ADS)

    Sanfeliu, T.; Jordán, M.; Gómez, E.; Alvarez, C.; Montero, M.

    2002-01-01

    Contaminating industrial emissions produced by the ceramics industries (including frit and enamel production) can be divided into dust emissions and emissions produced in high temperature activities. Processes of accumulation and precipitation on the substratum, of compounds enriched in certain elements used in this type of industry can occur. The objective of the present work was to identify the contribution of the emissions of the ceramics industries to the atmospheric particulate that is susceptible to depositing on vegetation and accumulating in the substratum. Samples obtained from high volume collectors were studied. Two zones were considered: zone A, a high volume collector located in the municipalities adjacent to the companies that were the object of the study; and zone B, a high volume collector further away from the said companies and adjacent to a power station and a refinery. The analysis techniques were X-ray diffraction, scanning electron microscopy (SEM), and ICP-MS. The results obtained by means of the X-ray diffraction technique showed a high percentage of clays in the samples, minerals used as raw materials (K-Ba feldspar, zircon silicate), indications of high temperature phases, as well as a background noise characteristic of material of low crystallinity. The SEM analysis confirmed the presence of vitreous particles, which are crystalline phases at high temperature typical of the production of a large variety of frits. The results obtained in the chemical analysis demonstrate that (a) the influence of the frits and enamel production on the high concentrations of Zr, Cu and Ce obtained in zone type A compared with zone B; (b) the affect of clays used as raw materials in the ceramics industry can be demonstrated by the high concentrations of Fe, Al and Mg. The weekly evolution showed two series of elements, a characteristic group of dust emissions and another group of tracers from high temperature processes.

  6. Atmospheric Aerosol Emissions Related to the Mediterranean Seawater Biogeochemistry

    NASA Astrophysics Data System (ADS)

    Sellegri, K.; Schwier, A.; Rose, C.; Gazeau, F. P. H.; Guieu, C.; D'anna, B.; Ebling, A. M.; Pey, J.; Marchand, N.; Charriere, B.; Sempéré, R.; Mas, S.

    2016-02-01

    Marine aerosols contribute significantly to the global aerosol load and consequently has an important impact on the Earth's climate. Different factors influence the way they are produced at the air/seawater interface. The sea state (whitecap coverage, temperature, etc. ) influence the size and concentration of primarily produced particles but also biogeochemical characteristics of the seawater influence both the physical and chemical primary fluxes to the atmosphere. An additional aerosol source of marine aerosol to the atmosphere is the formation of new particles by gaz-to-particle conversion, i.e. nucleation. How the seawater and surface microlayer biogeochemical compositions influences the aerosol emissions is still a large debate. In order to study marine emissions, one approach is to use semi-controlled environments such as mesocosms. Within the MedSea and SAM projects, we characterize the primary Sea Spray Aerosol (SSA) during mesocosms experiments performed during different seasons in the Mediteranean Sea. Mesocosms were either left unchanged as control or enriched by addition of nutriments in order to create different levels of phytoplanctonic activities. The mesocosms waters were daily analyzed for their chemical and biological composition (DOC, CDOM, TEP, Chl-a, virus, bacteria, phytoplankton and zooplankton concentrations). SSA production by bubble bursting was daily simulated in a dedicated set-up. The size segregated SSA number fluxes, cloud condensation nuclei (CCN) properties, and chemical composition were determined as a function of the seawater characteristics. We show that the SSA organic content was clearly correlated to the seawater Chl-a level, provided that the mesocosm was not enriched to create an artificial phytoplanctonic bloom. In our experiments, the enrichment of the seawater with natural surface microlayer did not impact the SSA organic content nor its CCN properties. At last, nucleation of secondary particles were observed to occur in

  7. Perturbation-free measurement of in situ di-nitrogen emissions from denitrification in nitrate-rich aquatic ecosystems.

    PubMed

    Qin, Shuping; Clough, Timothy; Luo, Jiafa; Wrage-Mönnig, Nicole; Oenema, Oene; Zhang, Yuming; Hu, Chunsheng

    2017-02-01

    Increased production of reactive nitrogen (Nr) from atmospheric di-nitrogen (N2) has greatly contributed to increased food production. However, enriching the biosphere with Nr has also caused a series of negative effects on global ecosystems, especially aquatic ecosystems. The main pathway converting Nr back into the atmospheric N2 pool is the last step in the denitrification process. Despite several attempts, there is still a need for perturbation-free methods for measuring in situ N2 fluxes from denitrification in aquatic ecosystems at the field scale. Such a method is needed to comprehensively quantify the N2 fluxes from aquatic ecosystems. Here we observed linear relationships between the δ(15)N-N2O signatures and the logarithmically transformed N2O/(N2+N2O) emission ratios. Through independent measurements, we verified that the perturbation-free N2 flux from denitrification in nitrate-rich aquatic ecosystems can be inferred from these linear relationships. Our method allowed the determination of field-scale in situ N2 fluxes from nitrate-rich aquatic ecosystems both with and without overlaying water. The perturbation-free in situ N2 fluxes observed by the new method were almost one order of magnitude higher than those by the sediment core method. The ability of aquatic ecosystems to remove Nr may previously have been severely underestimated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Radio Emission in Atmospheric Air Showers Measured by LOPES-30

    SciTech Connect

    Isar, P. G.

    2008-01-24

    When Ultra High Energy Cosmic Rays (UHECR) interact with particles in the Earth's atmosphere, they produce a shower of secondary particles propagating towards the ground. These relativistic particles emit synchrotron radiation in the radio frequency range when passing the Earth's magnetic field. The LOPES (LOFAR Prototype Station) experiment investigates the radio emission from these showers in detail and will pave the way to use this detection technique for large scale applications like in LOFAR (Low Frequency Array) and the Pierre Auger Observatory. The LOPES experiment is co-located and measures in coincidence with the air shower experiment KASCADE-Grande at Forschungszentrum Karlsruhe, Germany. LOPES has an absolute amplitude calibration array of 30 dipole antennas (LOPES-30). After one year of measurements of the single East-West polarization by all 30 antennas, recently, the LOPES-30 set-up was configured to perform dual-polarization measurements. Half of the antennas have been configured for measurements of the North-South polarization. Only by measuring at the same time both, the E-W and N-S polarization components of the radio emission, the geo-synchrotron effect as the dominant emission mechanism in air showers can be verified. The status of the measurements, including the absolute calibration procedure of the dual-polarized antennas as well as analysis of dual-polarized event examples are reported.

  9. Rapid exchange between atmospheric CO2 and carbonate anion intercalated within magnesium rich layered double hydroxide.

    PubMed

    Sahoo, Pathik; Ishihara, Shinsuke; Yamada, Kazuhiko; Deguchi, Kenzo; Ohki, Shinobu; Tansho, Masataka; Shimizu, Tadashi; Eisaku, Nii; Sasai, Ryo; Labuta, Jan; Ishikawa, Daisuke; Hill, Jonathan P; Ariga, Katsuhiko; Bastakoti, Bishnu Prasad; Yamauchi, Yusuke; Iyi, Nobuo

    2014-10-22

    The carbon cycle, by which carbon atoms circulate between atmosphere, oceans, lithosphere, and the biosphere of Earth, is a current hot research topic. The carbon cycle occurring in the lithosphere (e.g., sedimentary carbonates) is based on weathering and metamorphic events so that its processes are considered to occur on the geological time scale (i.e., over millions of years). In contrast, we have recently reported that carbonate anions intercalated within a hydrotalcite (Mg0.75Al0.25(OH)2(CO3)0.125·yH2O), a class of a layered double hydroxide (LDH), are dynamically exchanging on time scale of hours with atmospheric CO2 under ambient conditions. (Ishihara et al., J. Am. Chem. Soc. 2013, 135, 18040-18043). The use of (13)C-labeling enabled monitoring by infrared spectroscopy of the dynamic exchange between the initially intercalated (13)C-labeled carbonate anions and carbonate anions derived from atmospheric CO2. In this article, we report the significant influence of Mg/Al ratio of LDH on the carbonate anion exchange dynamics. Of three LDHs of various Mg/Al ratios of 2, 3, or 4, magnesium-rich LDH (i.e., Mg/Al ratio = 4) underwent extremely rapid exchange of carbonate anions, and most of the initially intercalated carbonate anions were replaced with carbonate anions derived from atmospheric CO2 within 30 min. Detailed investigations by using infrared spectroscopy, scanning electron microscopy, powder X-ray diffraction, elemental analysis, adsorption, thermogravimetric analysis, and solid-state NMR revealed that magnesium rich LDH has chemical and structural features that promote the exchange of carbonate anions. Our results indicate that the unique interactions between LDH and CO2 can be optimized simply by varying the chemical composition of LDH, implying that LDH is a promising material for CO2 storage and/or separation.

  10. Hydrogen emission from Jupiter: Hydrogen emission from sunlit atmosphere of Saturn

    NASA Technical Reports Server (NTRS)

    Shemansky, D. E.; Holberg, J. B.

    1987-01-01

    Successful IUE observations of the equatorial sunlit atmosphere of Jupiter and Saturn have been obtained. Spectra containing atomic and molecular hydrogen and solar reflection continuum emissions have been analyzed, with the purpose of determining the long term temporal behavior of the electroglow process. Quantitative estimates have been established for the first time using a model analysis of the short wavelength region of the spectrum. Both systems show varying degrees of long term variability in hydrogen emission rate, but the time scale is too short to determine whether there is a dependence on solar cycle activity. As part of the emission modeling program, a preliminary point source spreading function for the IUE SWP instrument has been established, suggesting a wavelength dependence in spectral line width different from previous analyses. Further IUE observations are planned for both Jupiter and Saturn.

  11. State of the Haze: The Causes and Consequences of a Hydrocarbon-rich Neoarchean Atmosphere

    NASA Astrophysics Data System (ADS)

    Zerkle, A.; Izon, G. J.; Claire, M.

    2016-12-01

    Atmospheric oxygen is thought to have rose irreversibly during the Great Oxidation Event (GOE) 2.4 billion-years-ago, though recent evidence shows that dynamic planetary transitions were also occurring prior to the oxidation of the atmosphere. We've recently documented perturbations in the reducing Neoarchean atmosphere, whereby the planet was periodically enshrouded in a CH4-rich haze. This scenario is based on coupled C- and S-isotope records from two continents, spanning a period of 200 million years [1-3]. A re-evaluation of these data at high resolution alongside additional proxies for trace element and nutrient analyses reveals that haze formed geologically rapidly, as a transient response to top-down stimulation of the biosphere. Net methane fluxes were ultimately controlled by the relative availability of organic-carbon and sulfate, with methanogenesis able to out-pace anaerobic methane oxidation in the low sulfate world of the Neoarchean. In addition, elevated CH4 flux to the atmosphere would have accelerated planetary hydrogen loss, expediting planetary oxidation and paving the way for the GOE [4]. These records suggest that the Neoarchean likely represented a unique state of the Earth System where links between the sulfur and methane cycles played a pivotal role in planetary oxidation and the contingent biological innovations that followed. [1] Zerkle et al. (2012) Nature Geoscience; [2] Farquhar et al. (2013) PNAS; [3] Izon et al. (2015) EPSL; [4] Izon et al. (in review).

  12. Atmospheric mercury emissions from polluted gold mining areas (Venezuela).

    PubMed

    García-Sánchez, A; Contreras, F; Adams, M; Santos, F

    2006-12-01

    Soil, waste rock and mud from mercury-gold amalgamation mining areas of El Callao (Venezuela) are highly enriched in Hg (0.5-500 microg g(-1)) relative to natural background concentrations (<0.1 microg g(-1)). Mercury fluxes to the atmosphere from twelve polluted sites of this area were measured in situ (6 a.m. to 8 p.m.) using a Plexiglas flux chamber connected to a portable mercury analyzer (model RA-915+; Lumex, St. Petersburg, Russia). Mercury fluxes ranged between 0.65 and 420.1 microg m(-2) h(-1), and the average flux range during the diurnal hours was 9.1-239.2 microg m(-2) h(-1). These flux values are five orders of magnitude higher than both reported world background Hg fluxes (1-69 ng m(-2) h(-1)) and the regional values, which are in the range 2-10 ng m(-2) h(-1). The flux results obtained in this study are, however, similar to those measured at Hg polluted sites such as chloro-alkali plants or polymetallic ore mining districts (>100,000 ng m(-2) h(-1)). The results from this study also show that Hg emissions from the soil are influenced by solar radiation, soil temperature and soil Hg concentration. Our data suggest that solar radiation may be the dominant factor affecting Hg degrees emission since the major species of mercury in polluted soil is Hg degrees (85-97% of total Hg). The simple release of Hg degrees vapor is probably the dominant process occurring with incident light in the field. The apparent activation energy for mercury emission indicates that the volatilization of mercury mainly occurred as a result of the vaporization of elemental mercury in soil. The degree of Hg emission differed significantly among the soil sites studied, which may be due to variations in soil texture, organic matter content and soil compaction.

  13. CARBON-RICH GIANT PLANETS: ATMOSPHERIC CHEMISTRY, THERMAL INVERSIONS, SPECTRA, AND FORMATION CONDITIONS

    SciTech Connect

    Madhusudhan, Nikku; Mousis, Olivier; Johnson, Torrence V.; Lunine, Jonathan I.

    2011-12-20

    The recent inference of a carbon-rich atmosphere, with C/O {>=} 1, in the hot Jupiter WASP-12b motivates the exotic new class of carbon-rich planets (CRPs). We report a detailed study of the atmospheric chemistry and spectroscopic signatures of carbon-rich giant (CRG) planets, the possibility of thermal inversions in their atmospheres, the compositions of icy planetesimals required for their formation via core accretion, and the apportionment of ices, rock, and volatiles in their envelopes. Our results show that CRG atmospheres probe a unique region in composition space, especially at high temperature (T). For atmospheres with C/O {>=} 1, and T {approx}> 1400 K in the observable atmosphere, most of the oxygen is bound up in CO, while H{sub 2}O is depleted and CH{sub 4} is enhanced by up to two or three orders of magnitude each, compared to equilibrium compositions with solar abundances (C/O = 0.54). These differences in the spectroscopically dominant species for the different C/O ratios cause equally distinct observable signatures in the spectra. As such, highly irradiated transiting giant exoplanets form ideal candidates to estimate atmospheric C/O ratios and to search for CRPs. We also find that the C/O ratio strongly affects the abundances of TiO and VO, which have been suggested to cause thermal inversions in highly irradiated hot Jupiter atmospheres. A C/O = 1 yields TiO and VO abundances of {approx}100 times lower than those obtained with equilibrium chemistry assuming solar abundances, at P {approx} 1 bar. Such a depletion is adequate to rule out thermal inversions due to TiO/VO even in the most highly irradiated hot Jupiters, such as WASP-12b. We estimate the compositions of the protoplanetary disk, the planetesimals, and the envelope of WASP-12b, and the mass of ices dissolved in the envelope, based on the observed atmospheric abundances. Adopting stellar abundances (C/O = 0.44) for the primordial disk composition and low-temperature formation conditions

  14. Exoplanet atmosphere. Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy.

    PubMed

    Stevenson, Kevin B; Désert, Jean-Michel; Line, Michael R; Bean, Jacob L; Fortney, Jonathan J; Showman, Adam P; Kataria, Tiffany; Kreidberg, Laura; McCullough, Peter R; Henry, Gregory W; Charbonneau, David; Burrows, Adam; Seager, Sara; Madhusudhan, Nikku; Williamson, Michael H; Homeier, Derek

    2014-11-14

    Exoplanets that orbit close to their host stars are much more highly irradiated than their solar system counterparts. Understanding the thermal structures and appearances of these planets requires investigating how their atmospheres respond to such extreme stellar forcing. We present spectroscopic thermal emission measurements as a function of orbital phase ("phase-curve observations") for the highly irradiated exoplanet WASP-43b spanning three full planet rotations using the Hubble Space Telescope. With these data, we construct a map of the planet's atmospheric thermal structure, from which we find large day-night temperature variations at all measured altitudes and a monotonically decreasing temperature with pressure at all longitudes. We also derive a Bond albedo of 0.18(-0.12)(+0.07) and an altitude dependence in the hot-spot offset relative to the substellar point. Copyright © 2014, American Association for the Advancement of Science.

  15. Spectral measurements of the atmospheric thermal infrared emission in Antarctica

    NASA Astrophysics Data System (ADS)

    Palchetti, L.; Bianchini, G.; Del Guasta, M.; Baglioni, A.

    2012-12-01

    A better understanding of radiative effects of water vapor and clouds could be achieved through better spectrally-resolved measurements of the atmospheric thermal emission, particularly in the far infrared (FIR) region below 650 cm-1. To explore this relatively unknown region, an experiment, named Radiative Properties of Water Vapor and Clouds in Antarctica (PRANA, "Proprieta' Radiative del vapore Acqueo e delle Nubi in Antartide"), is under way at Concordia station in Antarctica since December 2011. This experiment exploits the high altitude and extremely dry air conditions found on the Antarctic Plateau to extend the ground-based infrared sounding capabilities to the water vapor pure rotational band. The experiment includes a spectroradiometer for the spectral characterization of the downwelling longwave radiance in the 100-1400 cm-1 spectral region and a LIDAR to characterize a possible cloud coverage. Measurements will be carried on for two years, thus covering systematically different sky conditions. Moreover, routine integrated measurements of downwelling and upwelling shortwave and longwave radiation components (performed within the Baseline Surface Radiation Network - BSRN) and daily radiosoundings of water vapor and temperature vertical profiles are performed from the base, providing an independent knowledge of the state of the observed atmosphere. Detailed specifications of the complete set of instruments are shown along with a preliminary analysis of spectroscopic data. The analysis shows that a spectrally-resolved measurement has the capability to identify and to quantify the effect of the different atmospheric components on the radiation budget, and at the same time it shows that it is necessary to improve the spectroscopic characterization of the water vapor rotational band to be used in radiative transfer models in order to perform this task at best. The spectral signature of thin ice clouds is also identified in the measurements and characterized in

  16. Laser plasma emission of small particles in different gas atmospheres

    NASA Astrophysics Data System (ADS)

    Andreev, Alexander A.; Ueda, Toshitsugu; Wakamatsu, Muneaki

    2002-06-01

    The problem of laser pulse interaction with small solid particles in a gas atmosphere when detecting its parameters is a serous one in industrial and environmental applications. Previous investigations have shown the possibility of using the laser induced breakdown method. This method is very sensitive, but for a particle size of less than 0.1 micrometers the damage threshold of the solid target is very close to the breakdown point of pure gas. At breakdown, a small volume of dense hot plasma emits radiation by which the size and material of particles can be detected. We used an analytical model, simulation code and experiments to analyze this radiation and found that the emitted intensity varied with laser, gas and particle parameters. The increased dependence of SSP plasma emission rate on initial particle volume permits this method to be used for measuring small particle size by using emitted line spectrum at the late time stage.

  17. Mid- and far-infrared emission bands in C-rich proto-planetary nebulae

    NASA Technical Reports Server (NTRS)

    Omont, A.; Cox, P.; Moseley, S. Harvey; Glaccum, W.; Casey, Sean; Forveille, T.; Szczerba, R.; Chan, Kin-Wing

    1995-01-01

    The 16-48 micron spectra of five carbon-rich post-asymptotic giant branch (post-AGB) objects known to have an unidentified 21 micron feature in their IRAS low resolution spectrometer (LRS) spectra have been obtained using the Kuiper Airborne Observatory. A broad emission band extending from 24 to approximately 45 microns is present in the spectra of these objects. The strength of this band is variable from source to source and is not correlated with the strength of the 21 micron band. The possible identifications for the emitting material of both the 21 and 30 micron emission bands is discussed.

  18. A Methane-rich Proterozoic Atmosphere: Possible Link to the Neoproterozoic Snowball Earth Glaciations

    NASA Astrophysics Data System (ADS)

    Pavlov, A. A.; Kasting, J. F.; Hurtgen, M.; Arthur, M. A.

    2001-12-01

    An enhanced atmospheric greenhouse effect is required throughout Archean and Proterozoic to offset reduced solar luminosity. In the anoxic Archean atmosphere CH4 could have been an important greenhouse gas because of the decreased levels of the primary oxidants - OH, O and H2O2. However, after the major transition of the atmospheric oxidation state at 2.0-2.3 Gyr, the photochemical lifetimes of reduced atmospheric gases (like methane) should have been much shorter. Therefore, a common view of the Proterozoic climate suggests that CO2 was the major greenhouse gas (along with H2O) and that atmospheric CH4 concentrations were low. Here we argue that substantial methane levels could have been present in the Proterozoic atmosphere if O2 levels were somewhat lower than today. In agreement with earlier calculations, our 1-D photochemical model shows that the atmospheric methane mixing ratio is a highly nonlinear function of the surface methane flux. In our model, a factor of 10 increase in the methane flux results in a 60-fold increase of the surface methane concentration. 1-D climate calculations show that such a high methane abundance would keep the mean global surface temperature at ~296 K under reduced solar luminosity conditions ( ~17 % decreased solar luminosity at 2.3 Gyr ago), even if CO2 was present only at today's level. Here we propose several reasons why the net methane flux could have been indeed substantially higher in the Proterozoic, compared to the present day. In the modern ecosystem, 99.9 % of methane, produced by methanogens, is being consumed by methanotrophic bacteria. These bacteria would presumably consume much less methane if O2 levels were lower. Moreover, in the present day sulfate-rich ocean methanogens living in sediments are outcompeted by sulfate reducers and forced to live in the nutrient-poor environments. Methane is also consumed in marine sediments by anaerobic methanotrophs living in consortium with sulfate reducing bacteria. In an

  19. Sensitized erbium emission from silicon-rich nitride/silicon superlattice structures

    SciTech Connect

    Dal Negro, L.; Li, R.; Warga, J.; Basu, S. N.

    2008-05-05

    Erbium-doped silicon-rich nitride/silicon superlattice structures were fabricated by direct magnetron cosputtering deposition on Si substrates. Rapid thermal annealing resulted in the nucleation of small amorphous Si clusters, which efficiently sensitize 1.54 {mu}m emission via a nanosecond-fast nonresonant energy transfer process, providing an alternative route toward the fabrication of Si-compatible devices based on Er sensitization.

  20. Evidence of atmospheric nanoparticle formation from emissions of marine microorganisms

    NASA Astrophysics Data System (ADS)

    Sellegri, K.; Pey, J.; Rose, C.; Culot, A.; DeWitt, H. L.; Mas, S.; Schwier, A. N.; Temime-Roussel, B.; Charriere, B.; Saiz-Lopez, A.; Mahajan, A. S.; Parin, D.; Kukui, A.; Sempere, R.; D'Anna, B.; Marchand, N.

    2016-06-01

    Earth, as a whole, can be considered as a living organism emitting gases and particles into its atmosphere, in order to regulate its own temperature. In particular, oceans may respond to climate change by emitting particles that ultimately will influence cloud coverage. At the global scale, a large fraction of the aerosol number concentration is formed by nucleation of gas-phase species, but this process has never been directly observed above oceans. Here we present, using semicontrolled seawater-air enclosures, evidence that nucleation may occur from marine biological emissions in the atmosphere of the open ocean. We identify iodine-containing species as major precursors for new particle clusters' formation, while questioning the role of the commonly accepted dimethyl sulfide oxidation products, in forming new particle clusters in the region investigated and within a time scale on the order of an hour. We further show that amines would sustain the new particle formation process by growing the new clusters to larger sizes. Our results suggest that iodine-containing species and amines are correlated to different biological tracers. These observations, if generalized, would call for a substantial change of modeling approaches of the sea-to-air interactions.

  1. Estimating Longwave Atmospheric Emissivity in the Canadian Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Ebrahimi, S.; Marshall, S. J.

    2014-12-01

    Incoming longwave radiation is an important source of energy contributing to snow and glacier melt. However, estimating the incoming longwave radiation from the atmosphere is challenging due to the highly varying conditions of the atmosphere, especially cloudiness. We analyze the performance of some existing models included a physically-based clear-sky model by Brutsaert (1987) and two different empirical models for all-sky conditions (Lhomme and others, 2007; Herrero and Polo, 2012) at Haig Glacier in the Canadian Rocky Mountains. Models are based on relations between readily observed near-surface meteorological data, including temperature, vapor pressure, relative humidity, and estimates of shortwave radiation transmissivity (i.e., clear-sky or cloud-cover indices). This class of models generally requires solar radiation data in order to obtain a proxy for cloud conditions. This is not always available for distributed models of glacier melt, and can have high spatial variations in regions of complex topography, which likely do not reflect the more homogeneous atmospheric longwave emissions. We therefore test longwave radiation parameterizations as a function of near-surface humidity and temperature variables, based on automatic weather station data (half-hourly and mean daily values) from 2004 to 2012. Results from comparative analysis of different incoming longwave radiation parameterizations showed that the locally-calibrated model based on relative humidity and vapour pressure performs better than other published models. Performance is degraded but still better than standard cloud-index based models when we transfer the model to another site, roughly 900 km away, Kwadacha Glacier in the northern Canadian Rockies.

  2. Characterisation of iron-rich atmospheric submicrometre particles in the roadside environment

    NASA Astrophysics Data System (ADS)

    Sanderson, P.; Su, S. S.; Chang, I. T. H.; Delgado Saborit, J. M.; Kepaptsoglou, D. M.; Weber, R. J. M.; Harrison, Roy M.

    2016-09-01

    Human exposure to ambient metallic nanoparticles is an area of great interest owing to their potential health impacts. Ambient metallic nanoparticles found in the roadside environment are contributed by combustion engines and wear of brakes, tyres and road surfaces. Submicrometre atmospheric particles collected at two UK urban sites have been subject to detailed characterisation. It is found that many metallic nanoparticles collected from roadside sampling sites are rich in iron. The Fe-rich nanoparticles can be classified into (1) high Fe content (ca 90 wt%) with each alloying element less than 1 wt%; and (2) moderate Fe content (<75 wt%) with high manganese and silicon content. Both clusters contain a variable mix of minor constituents, Mn, S and Si being most important in the high-Fe group. The moderate Fe group also contains Zn, Cu, Ba, Al and Ca. The Fe-rich nanoparticles exhibit primary particle sizes ranging between 20 and 30 nm, although some much larger particles up to around 100 nm can also be observed, along with some very small particles of 10 nm or less. These tend to agglomerate forming clusters ranging from ∼200 nm to 1 μm in diameter. The iron-rich particles observed are oxides, taking the form of spheres or multifaceted regular polyhedra. Analysis by EELS shows that both high- and moderate-Fe groups include particles of FeO, Fe3O4, α-Fe2O3 and γ-Fe2O3 of which γ-Fe2O3 is the most prominent. Internal mixing of different Fe-oxides is not observed.

  3. Induction of indirect N2O and NO emissions by atmospheric nitrogen deposition in (semi-)natural ecosystems in Switzerland

    NASA Astrophysics Data System (ADS)

    Bühlmann, Tobias; Hiltbrunner, Erika; Körner, Christian; Rihm, Beat; Achermann, Beat

    2015-02-01

    During the past century atmospheric nitrogen deposition increased dramatically due to human activities worldwide. Currently, it exceeds the critical load for nitrogen (CLN) in over 90% of the Swiss forest area and raised bogs, in 80% of all fens and in 30% of species-rich grassland areas in Switzerland. Indirect gaseous nitrogen losses (HNO2, NO, N2O, N2) from these soils induced by atmospheric nitrogen deposition are likely to be substantial. However, the approaches to estimate these indirect N emissions provided by the international organisations (UNFCCC, IPCC; UNECE, EMEP/EEA) are based on agricultural data only. They may not be suitable to estimate the indirect emissions from (semi-)natural ecosystems such as forests, extensively used grassland, and wetlands. The present study aims at calculating ecosystem-specific annual indirect N2O and NO emissions of (semi-)natural ecosystems in Switzerland for the years 1990, 2000, 2007 and 2010 using a simple linear model similar to the international guidelines. The approach here is based on empirical data for (semi-)natural ecosystems, derived from a literature survey, is driven by atmospheric nitrogen deposition and is ecosystem-specific with a high spatial resolution of 100 m × 100 m. Our results show that such ecosystems represent a strong source of indirect N emissions induced by atmospheric nitrogen deposition and emitted 1.61 ± 0.32 Gg N2O-N and 2.51 ± 0.53 Gg NO-N into the atmosphere in Switzerland in the year 2010, corresponding to 21% of the total Swiss N2O emissions and 10% of the NOx emissions. Thanks to the reduction of N emissions and thereby reduced atmospheric N deposition, the indirect N2O and NO emissions from (semi-)natural ecosystems are estimated to have been both reduced by c. 20% from 1990 to 2010. We conclude that the source strength for N2O and NO emissions of (semi-)natural ecosystems have been underestimated by the current approaches of IPCC and EMEP/EEA by a factor of 4.4 and 17

  4. High Relative Humidity of Water-Rich Atmospheres and Its Implications

    NASA Astrophysics Data System (ADS)

    Ding, F.; Pierrehumbert, R.

    2015-12-01

    The onset of the runaway greenhouse of water vapor is one of the important criteria defining the inner edge of the habitable zone, and has been extensively studied in one-dimensional (1D) radiative-convective models. One limitation of 1D simulations is the assumption of the fully saturated troposphere. In the real atmosphere, sub-saturated regions are created by the large-scale subsidence of air. These regions significantly delay the onset of the runaway greenhouse by playing the role of "radiator fins" that allow more infrared radiation escaping the planet. Here, we show that the degree of sub-saturation in the atmosphere strongly depends on the mass of background non-condensable component (e.g., N2) in an idealized three-dimensional general circulation model (3D GCM). We specially develop the GCM to simulate the climate dynamics of water-rich atmospheres, based on the GFDL finite-volume dynamical core, a two-stream gray-radiation scheme and an energy-conserving convection scheme. Numerical simulation shows that the mid-troposphere becomes more saturated by reducing the background partial pressure from 105 Pa to 500 Pa. The increase in relative humidity can be explained by the increase in static stability of the atmosphere when water vapor becomes dominated. In general, the mass of the background non-condensable components on potentially habitable planets could be regulated by many processes including the volcanic outgassing, stellar wind and impact erosion. These processes may also play an important role in determining the inner edge of the habitable zone besides the stellar spectral type and planetary rotation.

  5. Abundances in the atmosphere of the metal-rich planet-host star HD 77338

    NASA Astrophysics Data System (ADS)

    Kushniruk, I. O.; Pavlenko, Ya. V.; Jenkins, J. S.; Jones, H. R. A.

    2014-12-01

    Abundances of Fe, Si, Ni, Ti, Na, Mg, Cu, Zn, Mn, Cr and Ca in the atmosphere of the K-dwarf HD 77338 are determined and discussed. HD 77338 hosts a hot Uranus-like planet and is currently the most metal-rich single star to host any planet. Determination of abundances was carried out in the framework of a self-consistent approach developed by Pavlenko et al. (2012). Abundances were computed iteratively by the ABEL8 code, and the process converged after 4 iterations. We find that most elements follow the iron abundance, however some of the iron peak elements are found to be over-abundant in this star.

  6. Processing of Amorphous Carbon Grains Produced in Hydrogen-Rich Atmosphere

    NASA Astrophysics Data System (ADS)

    Blanco, A.; Cappello, D.; Fonti, S.; Ientile, A.; Orofino, V.

    1999-01-01

    Recent laboratory experiments, compared with observations, have strongly suggested that the amount of hydrogen, present in the grain formation regions, around C-rich stars, can play a major role in the definition of the spectral characteristics of the freshly formed carbon dust particles. Such spectral characteristics could also be modified, during the thermal processing, due to the shock waves and/or the strong radiation field, that the grains undergo after their formation. In this work we report about a series of laboratory tests, during which submicronic dust particles of amorphous carbon, condensed in an hydrogen-rich atmosphere, have been processed, by means of two different methods. Some samples have been annealed into an oven at different temperatures, while others have been exposed to strong ultraviolet radiation. Their spectra have been obtained before and after the processing in the full range from ultraviolet (200 nm) to far infrared (0.1 mm). The results of the experiment are presented and discussed, together with their astrophysical implications

  7. Rich soil carbon and nitrogen but low atmospheric greenhouse gas fluxes from North Sulawesi mangrove swamps in Indonesia.

    PubMed

    Chen, Guang C; Ulumuddin, Yaya I; Pramudji, Sastro; Chen, Shun Y; Chen, Bin; Ye, Yong; Ou, Dan Y; Ma, Zhi Y; Huang, Hao; Wang, Jing K

    2014-07-15

    The soil to atmosphere fluxes of greenhouse gases N2O, CH4 and CO2 and their relationships with soil characteristics were investigated in three tropical oceanic mangrove swamps (Teremaal, Likupang and Kema) in North Sulawesi, Indonesia. Mangrove soils in North Sulawesi were rich in organic carbon and nitrogen, but the greenhouse gas fluxes were low in these mangroves. The fluxes ranged -6.05-13.14 μmol m(-2)h(-1), -0.35-0.61 μmol m(-2)h(-1) and -1.34-3.88 mmol m(-2)h(-1) for N2O, CH4 and CO2, respectively. The differences in both N2O and CH4 fluxes among different mangrove swamps and among tidal positions in each mangrove swamp were insignificant. CO2 flux was influenced only by mangrove swamps and the value was higher in Kema mangrove. None of the measured soil parameters could explain the variation of CH4 fluxes among the sampling plots. N2O flux was negatively related to porewater salinity, while CO2 flux was negatively correlated with water content and organic carbon. This study suggested that the low gas emissions due to slow metabolisms would lead to the accumulations of organic matters in North Sulawesi mangrove swamps.

  8. Maser emission of the most abundant SiO isotopomers in O-rich stars

    NASA Astrophysics Data System (ADS)

    Rizzo, J. R.; García Miró, C.; Cernicharo, J.

    2015-05-01

    SiO maser emission constitutes one of the most puzzling cases in spectroscopy. The overall inversion of the rotational transitions in each vibrational ladder is rather well understood. However, there are a number of anomalies in specific rotational transitions that are still unexplained. O-rich stars are probably the most powerful maser emitters known to date, and therefore the best candidates to model the SiO maser emission at different rotational and vibrational levels. In order to properly tackle the SiO excitation problem, it is vital to simultaneously observe a large number of SiO (and isotopomers) lines in a large and varied sample of sources. We profit the availability of new wideband backends to carry out a deep survey of ^{28}SiO, ^{29}SiO, and ^{30}SiO maser emission, in a sample of 67 evolved O-rich stars. The survey was done using the DSS-54 antenna at the Madrid Deep Space Communications complex in Robledo, and the IRAM 30m radio telescope at Pico Veleta. A total of 61 lines were observed, including rotational transitions from J=1→0 to J=5→4, for vibrational levels from 0 to 6. In this contribution, overall results of the survey are presented.

  9. Middle Atmosphere Sounder and Thermal Emission Radiometer - Master

    NASA Astrophysics Data System (ADS)

    Mlynczak, M. G.; Scott, D. K.; Esplin, R. W.; Bailey, S. M.; Randall, C. E.

    2014-12-01

    The Middle Atmosphere Sounder and Thermal Emission Radiometer (MASTER) instrument is an advanced infrared limb-scanning instrument designed to measure the thermal structure, chemical composition, and energy balance from the stratosphere to the lower thermosphere. MASTER builds on NASA's long and successful heritage of infrared limb scanners including the LIMS, HIRDLS, and SABER instruments. MASTER has exceptional radiometric sensitivity with a more efficient, compact, and lightweight design. An updated focal plane enables critical new science in the areas of the carbon budget closure, geomagnetically-driven ozone destruction, and auroral energy deposition, while virtually eliminating out of band contributions via dual filtering. MASTER will continue the SABER-TIMED and EOS-Aura records of temperature, lower stratospheric water vapor, ozone, methane, and thermospheric cooling by nitric oxide and carbon dioxide. MASTER's size and mass are specifically designed to allow flexibility in the choice of small satellite buses and low cost launch vehicles. The expanded focal plane enables a choice of channels applicable to science objectives in NASA's Earth Science and Heliophysics enterprises. Due to the long and successful heritage the MASTER instrument is at an exceptionally high technology readiness level. No new technologies are required to build the MASTER flight instrument.

  10. Infrared emission of hot water in the atmosphere of Mira

    NASA Astrophysics Data System (ADS)

    Yamamura, I.; de Jong, T.; Cami, J.

    1999-08-01

    The ISO/SWS spectrum of o Cet taken at its maximum exhibits an absorption-like feature between 3.5 and 4.0 mu m. We present evidence that the feature is due to emission of H_2O and SiO molecules, in a layer extended to about two stellar radii with an excitation temperature of 2000 K. These hot molecules are also observed in a spectrum of Z Cas near minimum, but this time in absorption. A simple plane-parallel model is used to fit the spectra of these two stars. The H_2O column densities and excitation temperatures in the layers are found to be similar in both stars. The difference of the H_2O band is thus primarily due to the layer size. The H_2O layers seem to be more extended at visual maximum, probably related to the stellar pulsation. The estimated lower limit to the local gas density in the layers of ~ 10(11) cm(-3) is in good agreement with theoretical predictions from dynamical model atmospheres. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) with the participation of ISAS and NASA. The SWS is a joint project of SRON and MPE.

  11. Atmospheric structure of the outer planets from thermal emission data

    NASA Technical Reports Server (NTRS)

    Orton, G. S.

    1981-01-01

    Methods for determining atmospheric structure exploit the opacities provided by the collision induced H2 dipole and the nu4 fundamental of CH4. In addition to earth-based observations, useful measurements of thermal emission from Jupiter and Saturn have been or soon will be made by several spacecraft, with results cross-checked with independent radio occultaion results. For Uranus and Neptune, only a limited set of whole-disk earth-based data exists. All the outer planets show evidence for stratospheric temperature inversions; temperature minima range from about 105 K for Jupiter and 87 K for Saturn, to roughly 55 K for Uranus and Neptune. Remaining problems may be resolved by better quantitative understanding of gas and aerosol absorption and scattering properties, chemical composition, and non-LTE source functions. Ultimately, temperature structure results must be supplemented by quantitative energy equilibrium models which will allow some meaning to be given to the relationships between such characteristics as temperature, clouds, incident solar and planetary radiation, and chemical composition.

  12. An approach for verifying biogenic greenhouse gas emissions inventories with atmospheric CO 2 concentration data

    DOE PAGES

    Ogle, Stephen; Davis, Kenneth J.; Lauvaux, Thomas; ...

    2015-03-10

    Verifying national greenhouse gas (GHG) emissions inventories is a critical step to ensure that reported emissions data to the United Nations Framework Convention on Climate Change (UNFCCC) are accurate and representative of a country’s contribution to GHG concentrations in the atmosphere. Verification could include a variety of evidence, but arguably the most convincing verification would be confirmation of a change in GHG concentrations in the atmosphere that is consistent with reported emissions to the UNFCCC. We report here on a case study evaluating this option based on a prototype atmospheric CO2 measurement network deployed in the Mid-Continent Region of themore » conterminous United States. We found that the atmospheric CO2 measurement data did verify the accuracy of the emissions inventory within the confidence limits of the emissions estimates, suggesting that this technology could be further developed and deployed more widely in the future for verifying reported emissions.« less

  13. What we can learn from measurements of air electric conductivity in 222Rn-rich atmosphere

    NASA Astrophysics Data System (ADS)

    Seran, E.; Godefroy, M.; Pili, E.; Michielsen, N.; Bondiguel, S.

    2017-02-01

    Electric conductivity of air is an important characteristic of the electric properties of an atmosphere. Testing instruments to measure electric conductivity ranging from 10-13 to 10-9 S m-1 in natural conditions found in the Earth atmosphere is not an easy task. One possibility is to use stratospheric balloon flights; another (and a simpler one) is to look for terrestrial environments with significant radioactive decay. In this paper we present measurements carried out with different types of conductivity sensors in two 222Rn-rich environments, i.e., in the Roselend underground tunnel (French Alps) and in the Institute of Radioprotection and Nuclear Safety BACCARA (BAnC de CAllibrage du RAdon) chamber. The concept of the conductivity sensor is based on the classical time relaxation method. New elements in our design include isolation of the sensor sensitive part (electrode) from the external electric field and sensor miniaturization. This greatly extends the application domain of the sensor and permits to measure air electric conductivity when the external electric field is high and varies from few tens of V m-1 to up to few tens of kV m-1. This is suitable to propose the instrument for a planetary mission. Two-fold objectives were attained as the outcome of these tests and their analysis. First was directly related to the performances of the conductivity sensors and the efficiency of the conductivity sensor design to shield the external electric field. Second objective aimed at understanding the decay mechanisms of 222Rn and its progeny in atmosphere and the impact of the enclosed space on the efficiency of gas ionization.

  14. Beta-Decay and Delayed Neutron Emission of Very Neutron-Rich Nuclei

    NASA Astrophysics Data System (ADS)

    Borzov, I. N.

    2014-09-01

    Extended self-consistent beta-decay model has been applied for beta-decay rates and delayed multi-neutron emission probabilities of quasi-spherical neutron-rich isotopes. The Gamow-Teller and first-forbidden decays are treated within the coordinate-space formalism of the continuum QRPA based on the density functional theory description of the ground state. A new set of the Fayans density functional parameters (DF3a) have been employed giving a better spin-orbit splitting due to a stronger tensor term. A provision has been included to fix the odd particle in the proper orbit (before variation). This accounts for ground-state spin inversion effect which has been shown to exist in the region of the most neutron-rich doubly-magic nucleus 78Ni.

  15. Simulating industrial emissions using atmospheric dispersion modeling system: model performance and source emission factors.

    PubMed

    El-Fadel, M; Abi-Esber, L

    2012-03-01

    In this paper, the Gaussian Atmospheric Dispersion Modeling System (ADMS4) was coupled with field observations of surface meteorology and concentrations of several air quality indicators (nitrogen oxides (NOx), carbon monoxide (CO), fine particulate matter (PM10) and sulfur dioxide (SO2)) to test the applicability of source emission factors set by the European Environment Agency (EEA) and the United States Environmental Protection Agency (USEPA) at an industrial complex. Best emission factors and data groupings based on receptor location, type of terrain and wind speed, were relied upon to examine model performance using statistical analyses of simulated and observed data. The model performance was deemed satisfactory for several scenarios when receptors were located at downwind sites with index of agreement 'd' values reaching 0.58, fractional bias 'FB' and geometric mean bias 'MG' values approaching 0 and 1, respectively, and normalized mean square error 'NMSE' values as low as 2.17. However, median ratios of predicted to observed concentrations 'Cp/Co' at variable downstream distances were 0.01, 0.36, 0.76 and 0.19 for NOx, CO, PM10 and SO2, respectively, and the fraction of predictions within a factor of two of observations 'FAC2' values were lower than 0.5, indicating that the model could not adequately replicate all observed variations in emittant concentrations. Also, the model was found to be significantly sensitive to the input emission factor bringing into light the deficiency in regulatory compliance modeling which often uses internationally reported emission factors without testing their applicability.

  16. Spectroscopic inferences from HIS measurements of atmospheric thermal emission

    NASA Technical Reports Server (NTRS)

    Revercomb, H. E.; Knuteson, R. O.; Smith, W. L.; Woolf, H. M.; Howell, H. B.

    1991-01-01

    Radiometrically accurate observations of the earth's emission spectrum from 3.8 to 16.6 microns have been made using the High-resolution Interferometer Sounder (HIS) to look downward from the NASA U2/ER2 aircraft or upward from the ground. These observations have been used to demonstrate the substantially improved vertical resolution of temperature and water vapor soundings derived from high resolution spectra (resolving power from 1800 to 3800), as compared to soundings from the low resolution filter radiometer observations used in current satellite sounders. The HIS observations have also demonstrated that Fourier Transform Infrared (FTIR) instruments are especially well suited to absolute emission measurements of broad spectral bands at high resolution. A fundamental advantage of FTIR instruments for accurate calibration is wavelength integrity, the same property which has made FTIR the standard for very high resolution absorption measurements. The long wavelength part of a HIS downwelling radiance spectrum is compared to a calculated spectrum. The calculation uses the AFGL HITRAN/86 line file and FASCOD2 line-by-line program with atmospheric state data from in situ measurements. In general, agreement between HIS and FASCOD2 spectra is remarkably good, a tribute to the current state of spectral line files and line-by-line codes. Reproducible differences between HIS observations and FASCOD2 line-by-line calculations lead to the following conclusions: (1) The FASCOD2 water vapor continuum in the longwave window region from 10 to 13 microns (750 to 1000 cm(exp -1)) gives reasonable agreement with radiance observations; (2) The model H2O continuum from 7 to 8 microns (1250 to 1425 cm(exp -2)) needs adjustment to reduce its contribution by about 60 percent; (3) CO2 absorption in the region from 13.1 to 14.3 microns (700 to 760 cm(exp -1)) is too small in the model; and (4) Water vapor line strengths in the region from 8.1 to 9.1 microns (1100 to 1230 cm(exp -1)) need

  17. Spectroscopic inferences from HIS measurements of atmospheric thermal emission

    NASA Astrophysics Data System (ADS)

    Revercomb, H. E.; Knuteson, R. O.; Smith, W. L.; Woolf, H. M.; Howell, H. B.

    1991-12-01

    Radiometrically accurate observations of the earth's emission spectrum from 3.8 to 16.6 microns have been made using the High-resolution Interferometer Sounder (HIS) to look downward from the NASA U2/ER2 aircraft or upward from the ground. These observations have been used to demonstrate the substantially improved vertical resolution of temperature and water vapor soundings derived from high resolution spectra (resolving power from 1800 to 3800), as compared to soundings from the low resolution filter radiometer observations used in current satellite sounders. The HIS observations have also demonstrated that Fourier Transform Infrared (FTIR) instruments are especially well suited to absolute emission measurements of broad spectral bands at high resolution. A fundamental advantage of FTIR instruments for accurate calibration is wavelength integrity, the same property which has made FTIR the standard for very high resolution absorption measurements. The long wavelength part of a HIS downwelling radiance spectrum is compared to a calculated spectrum. The calculation uses the AFGL HITRAN/86 line file and FASCOD2 line-by-line program with atmospheric state data from in situ measurements. In general, agreement between HIS and FASCOD2 spectra is remarkably good, a tribute to the current state of spectral line files and line-by-line codes. Reproducible differences between HIS observations and FASCOD2 line-by-line calculations lead to the following conclusions: (1) The FASCOD2 water vapor continuum in the longwave window region from 10 to 13 microns (750 to 1000 cm(exp -1)) gives reasonable agreement with radiance observations; (2) The model H2O continuum from 7 to 8 microns (1250 to 1425 cm(exp -2)) needs adjustment to reduce its contribution by about 60 percent; (3) CO2 absorption in the region from 13.1 to 14.3 microns (700 to 760 cm(exp -1)) is too small in the model; and (4) Water vapor line strengths in the region from 8.1 to 9.1 microns (1100 to 1230 cm(exp -1)) need

  18. A Coal-Fired Power Plant with Zero Atmospheric Emissions

    SciTech Connect

    Martinez-Frias, J; Aceves, S M; Smith, J R; Brandt, H

    2003-05-27

    This paper presents the thermodynamic analysis of a coal-based zero-atmospheric emissions electric power plant. The approach involves an oxygen-blown coal gasification unit. The resulting synthetic gas (syngas) is combusted with oxygen in a gas generator to produce the working fluid for the turbines. The combustion produces a gas mixture composed almost entirely of steam and carbon dioxide. These gases drive multiple turbines to produce electricity. The turbine discharge gases pass to a condenser where water is captured. A stream of carbon dioxide then results that can be used for enhanced oil recovery, or for sequestration. This analysis is based on a 400 MW electric power generating plant that uses turbines that are currently under development by a U.S. turbine manufacturer. The power plant has a net thermal efficiency of 42.6%. This efficiency is based on the lower heating value of the coal, and includes the energy necessary for coal gasification, air separation and for carbon dioxide separation and sequestration. The paper also presents an analysis of the cost of electricity (COE) and the cost of conditioning carbon dioxide for sequestration for the 400 MW power plant. Electricity cost is compared for three different gasification processes (Texaco, Shell, and Koppers-Totzek) and two types of coals (Illinois No.6 and Wyodak). Cost of electricity ranges from 5.16 {cents}/kWhr to 5.42 {cents}/kWhr, indicating that the cost of electricity varies by 5% for the three gasification processes considered and the two coal types used.

  19. Atmospheric nitrogen compounds II: emissions, transport, transformation, deposition and assessment

    NASA Astrophysics Data System (ADS)

    Aneja, Viney P.; Roelle, Paul A.; Murray, George C.; Southerland, James; Erisman, Jan Willem; Fowler, David; Asman, Willem A. H.; Patni, Naveen

    The Atmospheric Nitrogen Compounds II: Emissions, Transport, Transformation, Deposition and Assessment workshop was held in Chapel Hill, NC from 7 to 9 June 1999. This international conference, which served as a follow-up to the workshop held in March 1997, was sponsored by: North Carolina Department of Environment and Natural Resources; North Carolina Department of Health and Human Services, North Carolina Office of the State Health Director; Mid-Atlantic Regional Air Management Association; North Carolina Water Resources Research Institute; Air and Waste Management Association, RTP Chapter; the US Environmental Protection Agency and the North Carolina State University (College of Physical and Mathematical Sciences, and North Carolina Agricultural Research Service). The workshop was structured as an open forum at which scientists, policy makers, industry representatives and others could freely share current knowledge and ideas, and included international perspectives. The workshop commenced with international perspectives from the United States, Canada, United Kingdom, the Netherlands, and Denmark. This article summarizes the findings of the workshop and articulates future research needs and ways to address nitrogen/ammonia from intensively managed animal agriculture. The need for developing sustainable solutions for managing the animal waste problem is vital for shaping the future of North Carolina. As part of that process, all aspects of environmental issues (air, water, soil) must be addressed as part of a comprehensive and long-term strategy. There is an urgent need for North Carolina policy makers to create a new, independent organization that will build consensus and mobilize resources to find technologically and economically feasible solutions to this aspect of the animal waste problem.

  20. Quantifying greenhouse-gas emissions from atmospheric measurements: a critical reality check for climate legislation.

    PubMed

    Weiss, Ray F; Prinn, Ronald G

    2011-05-28

    Emissions reduction legislation relies upon 'bottom-up' accounting of industrial and biogenic greenhouse-gas (GHG) emissions at their sources. Yet, even for relatively well-constrained industrial GHGs, global emissions based on 'top-down' methods that use atmospheric measurements often agree poorly with the reported bottom-up emissions. For emissions reduction legislation to be effective, it is essential that these discrepancies be resolved. Because emissions are regulated nationally or regionally, not globally, top-down estimates must also be determined at these scales. High-frequency atmospheric GHG measurements at well-chosen station locations record 'pollution events' above the background values that result from regional emissions. By combining such measurements with inverse methods and atmospheric transport and chemistry models, it is possible to map and quantify regional emissions. Even with the sparse current network of measurement stations and current inverse-modelling techniques, it is possible to rival the accuracies of regional 'bottom-up' emission estimates for some GHGs. But meeting the verification goals of emissions reduction legislation will require major increases in the density and types of atmospheric observations, as well as expanded inverse-modelling capabilities. The cost of this effort would be minor when compared with current investments in carbon-equivalent trading, and would reduce the volatility of that market and increase investment in emissions reduction.

  1. Modelling marine emissions and atmospheric distributions of halocarbons and dimethyl sulfide: the influence of prescribed water concentration vs. prescribed emissions

    NASA Astrophysics Data System (ADS)

    Lennartz, S. T.; Krysztofiak, G.; Marandino, C. A.; Sinnhuber, B.-M.; Tegtmeier, S.; Ziska, F.; Hossaini, R.; Krüger, K.; Montzka, S. A.; Atlas, E.; Oram, D. E.; Keber, T.; Bönisch, H.; Quack, B.

    2015-10-01

    Marine-produced short-lived trace gases such as dibromomethane (CH2Br2), bromoform (CHBr3), methyliodide (CH3I) and dimethyl sulfide (DMS) significantly impact tropospheric and stratospheric chemistry. Describing their marine emissions in atmospheric chemistry models as accurately as possible is necessary to quantify their impact on ozone depletion and Earth's radiative budget. So far, marine emissions of trace gases have mainly been prescribed from emission climatologies, thus lacking the interaction between the actual state of the atmosphere and the ocean. Here we present simulations with the chemistry climate model EMAC (ECHAM5/MESSy Atmospheric Chemistry) with online calculation of emissions based on surface water concentrations, in contrast to directly prescribed emissions. Considering the actual state of the model atmosphere results in a concentration gradient consistent with model real-time conditions at the ocean surface and in the atmosphere, which determine the direction and magnitude of the computed flux. This method has a number of conceptual and practical benefits, as the modelled emission can respond consistently to changes in sea surface temperature, surface wind speed, sea ice cover and especially atmospheric mixing ratio. This online calculation could enhance, dampen or even invert the fluxes (i.e. deposition instead of emissions) of very short-lived substances (VSLS). We show that differences between prescribing emissions and prescribing concentrations (-28 % for CH2Br2 to +11 % for CHBr3) result mainly from consideration of the actual, time-varying state of the atmosphere. The absolute magnitude of the differences depends mainly on the surface ocean saturation of each particular gas. Comparison to observations from aircraft, ships and ground stations reveals that computing the air-sea flux interactively leads in most of the cases to more accurate atmospheric mixing ratios in the model compared to the computation from prescribed emissions

  2. SUPERBURST MODELS FOR NEUTRON STARS WITH HYDROGEN- AND HELIUM-RICH ATMOSPHERES

    SciTech Connect

    Keek, L.; Heger, A.; In 't Zand, J. J. M.

    2012-06-20

    Superbursts are rare day-long type I X-ray bursts due to carbon flashes on accreting neutron stars in low-mass X-ray binaries. They heat the neutron star envelope such that the burning of accreted hydrogen and helium becomes stable, and the common shorter X-ray bursts are quenched. Short bursts reappear only after the envelope cools down. We study multi-zone one-dimensional models of the neutron star envelope, in which we follow carbon burning during the superburst, and we include hydrogen and helium burning in the atmosphere above. We investigate the cases of both a solar-composition and a helium-rich atmosphere. This allows us to study for the first time a wide variety of thermonuclear burning behavior as well as the transitions between the different regimes in a self-consistent manner. For solar composition, burst quenching ends much sooner than previously expected. This is because of the complex interplay between the 3{alpha}, hot CNO, and CNO breakout reactions. Stable burning of hydrogen and helium transitions via marginally stable burning (mHz quasi-periodic oscillations) to less energetic bursts with short recurrence times. We find a short-lived bursting mode where weaker and stronger bursts alternate. Eventually the bursting behavior changes back to that of the pre-superburst bursts. Because of the scarcity of observations, this transition has not been directly detected after a superburst. Using the MINBAR burst catalog we identify the shortest upper limit on the quenching time for 4U 1636-536, and derive further constraints on the timescale on which bursts return.

  3. Sulfur-rich geothermal emissions elevate acid aerosol levels in metropolitan Taipei.

    PubMed

    Lin, Chih-Hung; Mao, I-Fang; Tsai, Pei-Hsien; Chuang, Hsin-Yi; Chen, Yi-Ju; Chen, Mei-Lien

    2010-08-01

    Several studies have demonstrated that millions of people globally are potentially exposed to volcanic gases. Hydrogen sulfide is a typical gas in volcanic and geothermal areas. The gas is toxic at high concentrations that predominantly affects the nervous, cardiovascular, and respiratory systems. The WHO air quality guideline for hydrogen sulfide is 150 microg m(-3) (105 ppb). The northwest part of Taipei is surrounded by sulfur-rich geothermal and hot springs. Active fumaroles and bubbling springs around the geothermal area emit acidic gases. In combination with automobile emissions, the pollution of acid aerosols is characteristic of the metropolis. This study considered sulfur-rich geothermal, suburban and downtown locations of this metropolis to evaluate geothermally emitted acid aerosol and H(2)S pollution. Acid aerosols were collected using a honeycomb denuder filter pack sampling system (HDS), and then analyzed by ion chromatography (IC). Results indicated that long-term geothermal emissions, automobile emissions and photochemical reactions have led to significant variations in air pollution among regions of metropolitan Taipei. The highest H(2)S concentration was 1705 ppb in the geothermal area with low traffic density and the mean concentration was 404.06 ppb, which was higher than WHO guideline and might cause eye irritation. The SO(2) concentrations were relatively low (mean concentration was 3.9 ppb) in this area. It may partially result from the chemical reduction reaction in the geothermal emission, which converted the SO(2) gas into SO(4)(2-) and H(2)S. Consequently, very high sulfate concentrations (mean concentration higher than 25.0 microg m(-3)) were also observed in the area. The geothermal areas also emitted relatively high levels of aerosol acidity, Cl(-), F(-), PO(4)(3-), and N-containing aerosols. As a result, concentrations of HNO(3), NO(2)(-), PO(4)(3-), and SO(4)(2-) in metropolitan Taipei are significantly higher than those in other

  4. DSA laser measurements and atmospheric diffusion models for the estimation of the gas emission flux by spot source fields: methods and experimental results

    NASA Astrophysics Data System (ADS)

    Cuccoli, Fabrizio; Facheris, Luca; Vaselli, Orlando

    2006-09-01

    A simple method for estimating the gas emission flux by spot source fields based on IR laser measurements and atmospheric diffusion models is presented. The method is based on a proper arrangement of the optical links around the emission area, over which the determination of the gas integral concentration is required. The first objective of such measurements is to tune the parameters of a basic diffusion model in order to estimate, as second objective, the gas emission flux by applying the tuned model to experimental measurements. After discussing the proposed model and method, experimental data obtained from some CO II-rich natural discharges in Tuscany (Central Italy) are presented

  5. Allowed and unique first-forbidden stellar electron emission rates of neutron-rich copper isotopes

    NASA Astrophysics Data System (ADS)

    Majid, Muhammad; Nabi, Jameel-Un; Daraz, Gul

    2017-06-01

    The allowed charge-changing transitions are the most common weak interaction processes of spin-isospin form that play a crucial role in several nuclear/astrophysical processes. The first-forbidden (FF) transition becomes important, in the circumstances where allowed Gamow-Teller (GT) transitions are unfavored, specifically for neutron-rich nuclei due to phase space considerations. In this paper deformed proton-neutron quasi-particle random phase approximation (pn-QRPA) model is applied, for the first time, for the estimation of allowed GT and unique first-forbidden (U1F) transitions (|Δ J| = 2) of neutron rich copper isotopes in mass range 72 ≤ A ≤ 82 under stellar conditions. We compared our computed terrestrial β-decay half-life values with previous calculations and experimental results. It was concluded that the pn-QRPA calculation is in good accordance with measured data. Our study suggests that the addition of rank (0 and 1) operators in FF transitions can further improve the comparison which remain unattended at this stage. The deformed pn-QRPA model was employed for the estimation of GT and U1F stellar electron emission (β--decay) rates over wide range of stellar temperature (0.01 GK-30 GK) and density (10-10^{11} g/cm3) domains for astrophysical applications. Our study shows that, in high density and low temperature regions, the contribution of U1F rates to total electron emission rates of neutron-rich copper nuclei is negligible.

  6. Pathways to Earth-like atmospheres. Extreme ultraviolet (EUV)-powered escape of hydrogen-rich protoatmospheres.

    PubMed

    Lammer, Helmut; Kislyakova, K G; Odert, P; Leitzinger, M; Schwarz, R; Pilat-Lohinger, E; Kulikov, Yu N; Khodachenko, M L; Güdel, M; Hanslmeier, M

    2011-12-01

    We discuss the evolution of the atmosphere of early Earth and of terrestrial exoplanets which may be capable of sustaining liquid water oceans and continents where life may originate. The formation age of a terrestrial planet, its mass and size, as well as the lifetime in the EUV-saturated early phase of its host star play a significant role in its atmosphere evolution. We show that planets even in orbits within the habitable zone of their host stars might not lose nebular- or catastrophically outgassed initial protoatmospheres completely and could end up as water worlds with CO2 and hydrogen- or oxygen-rich upper atmospheres. If an atmosphere of a terrestrial planet evolves to an N2-rich atmosphere too early in its lifetime, the atmosphere may be lost. We show that the initial conditions set up by the formation of a terrestrial planet and by the evolution of the host star's EUV and plasma environment are very important factors owing to which a planet may evolve to a habitable world. Finally we present a method for studying the discussed atmosphere evolution hypotheses by future UV transit observations of terrestrial exoplanets.

  7. Pathways to Earth-Like Atmospheres. Extreme Ultraviolet (EUV)-Powered Escape of Hydrogen-Rich Protoatmospheres

    NASA Astrophysics Data System (ADS)

    Lammer, Helmut; Kislyakova, K. G.; Odert, P.; Leitzinger, M.; Schwarz, R.; Pilat-Lohinger, E.; Kulikov, Yu. N.; Khodachenko, M. L.; Güdel, M.; Hanslmeier, A.

    2011-12-01

    We discuss the evolution of the atmosphere of early Earth and of terrestrial exoplanets which may be capable of sustaining liquid water oceans and continents where life may originate. The formation age of a terrestrial planet, its mass and size, as well as the lifetime in the EUV-saturated early phase of its host star play a significant role in its atmosphere evolution. We show that planets even in orbits within the habitable zone of their host stars might not lose nebular- or catastrophically outgassed initial protoatmospheres completely and could end up as water worlds with CO2 and hydrogen- or oxygen-rich upper atmospheres. If an atmosphere of a terrestrial planet evolves to an N2-rich atmosphere too early in its lifetime, the atmosphere may be lost. We show that the initial conditions set up by the formation of a terrestrial planet and by the evolution of the host star's EUV and plasma environment are very important factors owing to which a planet may evolve to a habitable world. Finally we present a method for studying the discussed atmosphere evolution hypotheses by future UV transit observations of terrestrial exoplanets.

  8. Downward transport of ozone rich air and implications for atmospheric chemistry in the Amazon rainforest

    NASA Astrophysics Data System (ADS)

    Gerken, Tobias; Wei, Dandan; Chase, Randy J.; Fuentes, Jose D.; Schumacher, Courtney; Machado, Luiz A. T.; Andreoli, Rita V.; Chamecki, Marcelo; Ferreira de Souza, Rodrigo A.; Freire, Livia S.; Jardine, Angela B.; Manzi, Antonio O.; Nascimento dos Santos, Rosa M.; von Randow, Celso; dos Santos Costa, Patrícia; Stoy, Paul C.; Tóta, Julio; Trowbridge, Amy M.

    2016-01-01

    From April 2014 to January 2015, ozone (O3) dynamics were investigated as part of GoAmazon 2014/5 project in the central Amazon rainforest of Brazil. Just above the forest canopy, maximum hourly O3 mixing ratios averaged 20 ppbv (parts per billion on a volume basis) during the June-September dry months and 15 ppbv during the wet months. Ozone levels occasionally exceeded 75 ppbv in response to influences from biomass burning and regional air pollution. Individual convective storms transported O3-rich air parcels from the mid-troposphere to the surface and abruptly enhanced the regional atmospheric boundary layer by as much as 25 ppbv. In contrast to the individual storms, days with multiple convective systems produced successive, cumulative ground-level O3 increases. The magnitude of O3 enhancements depended on the vertical distribution of O3 within storm downdrafts and origin of downdrafts in the troposphere. Ozone mixing ratios remained enhanced for > 2 h following the passage of storms, which enhanced chemical processing of rainforest-emitted isoprene and monoterpenes. Reactions of isoprene and monoterpenes with O3 are modeled to generate maximum hydroxyl radical formation rates of 6 × 106 radicals cm-3s-1. Therefore, one key conclusion of the present study is that downdrafts of convective storms are estimated to transport enough O3 to the surface to initiate a series of reactions that reduce the lifetimes of rainforest-emitted hydrocarbons.

  9. Modelling marine emissions and atmospheric distributions of halocarbons and DMS: the influence of prescribed water concentration vs. prescribed emissions

    NASA Astrophysics Data System (ADS)

    Lennartz, S. T.; Krysztofiak-Tong, G.; Marandino, C. A.; Sinnhuber, B.-M.; Tegtmeier, S.; Ziska, F.; Hossaini, R.; Krüger, K.; Montzka, S. A.; Atlas, E.; Oram, D.; Keber, T.; Bönisch, H.; Quack, B.

    2015-06-01

    Marine produced short-lived trace gases such as dibromomethane (CH2Br2), bromoform (CHBr3), methyliodide (CH3I) and dimethylsulfide (DMS) significantly impact tropospheric and stratospheric chemistry. Describing their marine emissions in atmospheric chemistry models as accurately as possible is necessary to quantify their impact on ozone depletion and the Earth's radiative budget. So far, marine emissions of trace gases have mainly been prescribed from emission climatologies, thus lacking the interaction between the actual state of the atmosphere and the ocean. Here we present simulations with the chemistry climate model EMAC with online calculation of emissions based on surface water concentrations, in contrast to directly prescribed emissions. Considering the actual state of the model atmosphere results in a concentration gradient consistent with model real-time conditions at ocean surface and atmosphere, which determine the direction and magnitude of the computed flux. This method has a number of conceptual and practical benefits, as the modelled emission can respond consistently to changes in sea surface temperature, surface wind speed, sea ice cover and especially atmospheric mixing ratio. This online calculation could enhance, dampen or even invert the fluxes (i.e. deposition instead of emissions) of VSLS. We show that differences between prescribing emissions and prescribing concentrations (-28 % for CH2Br2 to +11 % for CHBr3) result mainly from consideration of the actual, time-varying state of the atmosphere. The absolute magnitude of the differences depends mainly on the surface ocean saturation of each particular gas. Comparison to observations from aircraft, ships and ground stations reveals that computing the air-sea flux interactively leads in most of the cases to more accurate atmospheric mixing ratios in the model compared to the computation from prescribed emissions. Calculating emissions online also enables effective testing of different air

  10. A semi-analytical emission model for diffusion flame, rich/lean and premixed lean combustors

    SciTech Connect

    Rizk, N.K.; Mongia, H.C.

    1995-04-01

    To enhanced gas turbine combustor performance and emissions characteristics, better design methods need to be developed. In the present investigation, an emission model that simulates a detailed chemical kinetic scheme has been developed to provide the rate of reactions of the parent fuel, an intermediate hydrocarbon compound, CO, and H{sub 2}. The intermediate fuel has variable carbon and hydrogen contents depending on operating conditions, that were selected in the development effort to simulate actual operating conditions, that were selected in the development effort to simulate actual operation of rich/lean, diffusion flame, and lean combustor concepts. The developed reaction rate expressions address also the limited reaction rates that may occur in the near-wall regions of the combustor due to the admittance of radial air jets and cooling air in these regions. The validation effort included the application of the developed model to a combustor simulated by a multiple-reactor arrangement. The results indicate the accurate duplication of the calculations obtained from the detailed kinetic scheme using the developed model. This illustrates the great potential of using such a unified approach to guide the design of various types of combustor to meet the more stringent emissions and performance requirements of next-generation gas turbine engines.

  11. Assessment of N2O emission from a photobioreactor treating ammonia-rich swine wastewater digestate.

    PubMed

    Mezzari, Melissa P; da Silva, Márcio L B; Nicoloso, Rodrigo S; Ibelli, Adriana M G; Bortoli, Marcelo; Viancelli, Aline; Soares, Hugo M

    2013-12-01

    This study investigated the interactions between naturally occurring bacteria and the microalgae Chlorella vulgaris within a lab scale photobioreactor treating ammonia-rich swine wastewater digestate effluent. Nitrification and denitrification were assessed by targeting ammonia monoxygenases (amoA), nitrate (narG), nitrite (nirS), nitric oxide (norB) and nitrous oxide (nosZ) reductases genes. Oxygen produced from microalgae photosynthesis stimulated nitrification. Under limiting carbon availability (i.e., <1.44 for mg TOC/mg NO2-N and 1.72 for mg TOC/mg NO3-N), incomplete denitrification led to accumulation of NO2 and NO3. Significant N2O emission (up to 118 μg N2O-N) was linked to NO2 metabolism in Chlorella. The addition of acetate as external carbon source recovered heterotrophic denitrification activity suppressing N2O emission. Effluent methane concentrations trapped within photobioreactor was removed concomitantly with ammonia. Overall, closed photobioreactors can be built to effectively remove nitrogen and mitigate simultaneously greenhouse gases emissions that would occur otherwise in open microalgae-based wastewater treatment systems.

  12. Abundant Acceptor Emission from Nitrogen-Doped ZnO Films Prepared by Atomic Layer Deposition under Oxygen-Rich Conditions.

    PubMed

    Guziewicz, E; Przezdziecka, E; Snigurenko, D; Jarosz, D; Witkowski, B S; Dluzewski, P; Paszkowicz, W

    2017-08-09

    Nitrogen-doped and undoped ZnO films were grown by thermal atomic layer deposition (ALD) under oxygen-rich conditions. Low-temperature photoluminescence spectra reveal a dominant donor-related emission at 3.36 eV and characteristic acceptor-related emissions at 3.302 and 3.318 eV. Annealing at 800 °C in oxygen atmosphere leads to conversion of conductivity from n- to p-type, which is reflected in photoluminescence spectra. Annealing does not increase any acceptor-related emission in the undoped sample, while in the ZnO:N it leads to a considerable enhancement of the photoluminescence at 3.302 eV. The high resolution cathodoluminescence cross-section images show different spatial distribution of the donor-related and the acceptor-related emissions, which complementarily contribute to the overall luminescence of the annealed ZnO:N material. Similar area of both emissions indicates that the acceptor luminescence comes neither from the grain boundaries nor from stacking faults. Moreover, in ZnO:N the acceptor-emission regions are located along the columns of growth, which shows a perspective to achieve a ZnO:N material with homogeneous acceptor conductivity at least at the micrometer scale.

  13. Heterodyne detection of CO2 emission lines and wind velocities in the atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Betz, A. L.; Johnson, M. A.; Mclaren, R. A.; Sutton, E. C.

    1975-01-01

    Strong 10 micrometer line emission from (C-12)(O-16)2 in the upper atmosphere of Venus was detected by heterodyne techniques. Observations of the absolute Doppler shift of the emission features indicate mean zonal wind velocities less than 10 m/sec in the upper atmosphere near the equator. No evidence was found of the 100 m/sec wind velocity implied by the apparent 4-day rotation period of ultraviolet cloud features.

  14. Heterodyne detection of CO2 emission lines and wind velocities in the atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Betz, A. L.; Johnson, M. A.; Mclaren, R. A.; Sutton, E. C.

    1976-01-01

    Strong 10-micron line emission from (C-12)(O-16)2 in the upper atmosphere of Venus has been detected by heterodyne techniques. Observations of the absolute Doppler shift of the emission features indicated mean zonal wind velocities less than 10 m/s in the upper atmosphere near the equator. No evidence was found for the 100-m/s wind velocity implied by the apparent four-day rotation period of ultraviolet cloud features.

  15. Heterodyne detection of CO2 emission lines and wind velocities in the atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Betz, A. L.; Johnson, M. A.; Mclaren, R. A.; Sutton, E. C.

    1975-01-01

    Strong 10 micrometer line emission from (c-12)(o-16)2 in the upper atmosphere of Venus was detected by heterodyne techniques. Observations of the absolute Doppler shift of the emission features indicate mean zonal wind velocities less than 10 m/sec in the upper atmosphere near the equator. No evidence was found of the 100 m/sec wind velocity implied by the apparent 4-day rotation period of ultraviolet cloud features.

  16. Variation of Atmospheric Biogenic Emissions in a coupled Radiative-Photochemical Model

    NASA Astrophysics Data System (ADS)

    Rauer, H.; Grenfell, J. L.; Stracke, B.; von Paris, P.; Gebauer, S.; Godolt, M.

    2008-09-01

    Abstract We investigate the effect of varying biogenic surface emissions in our atmospheric column model upon atmospheric biomarkers such as ozone and nitrous oxide as well as related compounds such as water. Ozone in particular features a complex photochemistry which can interact with biogenic emissions in a non-linear fashion. Our aim is to estimate the possible range of biomarker signals which can arise from earthlike exoplanets.

  17. Detection of C-13O radio emission from C-13-rich carbon stars

    NASA Technical Reports Server (NTRS)

    Jura, M.; Kahane, C.; Omont, A.

    1988-01-01

    A high ratio of C-13O radio emission in the J = 1-0 rotational line has been detected from three mass-losing carbon stars which optical data indicate have high C-13/C12 ratios. Since chemical fractionation, isotope-dependent photodissociation and opacity in the rotational and vibrational lines may not raise significantly the C-13O ratio above the actual C-13/C-12 ratio in these circumstellar envelopes, the relative abundance of C-13 in these stars might be even greater by perhaps a factor of two than previously believed. About 15 percent of all luminous carbon stars are C-13-rich, and these stars may play a significant role in the enhancement in the C-13/C12 ratio that has occurred during the past 4.6 billion years since the formation of the sun.

  18. A far-infrared emission feature in carbon-rich stars and planetary nebulae

    NASA Technical Reports Server (NTRS)

    Forrest, W. J.; Houck, J. R.; Mccarthy, J. F.

    1981-01-01

    The 16-30 micron spectra of several carbon stars and the planetary nebulae IC 418 and NGC 6572 have been obtained using the NASA C-141 Kuiper Airborne Observatory. A newly observed emission feature appears in the spectrum of IRC +10216 and several other carbon stars at wavelengths greater than 24 microns. The feature is interpreted as resulting from a solid-state resonance in the dust grains which have condensed around these stars. A similar feature appears in the spectra of IC 418 and NGC 6572, implying that the same type of dust is present. Since the dust probably condensed from a carbon-rich gas, this indicates an evolutionary link between carbon stars and these planetary nebulae. No identification for the grain material has been found, but some clues are apparent which could aid in the identification.

  19. Significant contribution of combustion-related emissions to the atmospheric phosphorus budget

    NASA Astrophysics Data System (ADS)

    Wang, Rong; Balkanski, Yves; Boucher, Olivier; Ciais, Philippe; Peñuelas, Josep; Tao, Shu

    2015-01-01

    Atmospheric phosphorus fertilizes plants and contributes to Earth's biogeochemical phosphorus cycle. However, calculations of the global budget of atmospheric phosphorus have been unbalanced, with global deposition exceeding estimated emissions from dust and sea-salt transport, volcanic eruptions, biogenic sources and combustion of fossil fuels, biofuels and biomass, the latter of which thought to contribute about 5% of total emissions. Here we use measurements of the phosphorus content of various fuels and estimates of the partitioning of phosphorus during combustion to calculate phosphorus emissions to the atmosphere from all combustion sources. We estimate combustion-related emissions of 1.8 Tg P yr-1, which represent over 50% of global atmospheric sources of phosphorus. Using these estimates in atmospheric transport model simulations, we find that the total global emissions of atmospheric phosphorus (3.5 Tg P yr-1) translate to a depositional sink of 2.7 Tg P yr-1 over land and 0.8 Tg P yr-1 over the oceans. The modelled spatial patterns of phosphorus deposition agree with observations from globally distributed measurement stations, and indicate a near balance of the phosphorus budget. Our finding suggests that the perturbation of the global phosphorus cycle by anthropogenic emissions is larger thanpreviously thought.

  20. Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions

    USGS Publications Warehouse

    Isaksen, Ivar S.A.; Gauss, Michael; Myhre, Gunnar; Walter Anthony, Katey M.; Ruppel, Carolyn

    2011-01-01

    The magnitude and feedbacks of future methane release from the Arctic region are unknown. Despite limited documentation of potential future releases associated with thawing permafrost and degassing methane hydrates, the large potential for future methane releases calls for improved understanding of the interaction of a changing climate with processes in the Arctic and chemical feedbacks in the atmosphere. Here we apply a “state of the art” atmospheric chemistry transport model to show that large emissions of CH4 would likely have an unexpectedly large impact on the chemical composition of the atmosphere and on radiative forcing (RF). The indirect contribution to RF of additional methane emission is particularly important. It is shown that if global methane emissions were to increase by factors of 2.5 and 5.2 above current emissions, the indirect contributions to RF would be about 250% and 400%, respectively, of the RF that can be attributed to directly emitted methane alone. Assuming several hypothetical scenarios of CH4 release associated with permafrost thaw, shallow marine hydrate degassing, and submarine landslides, we find a strong positive feedback on RF through atmospheric chemistry. In particular, the impact of CH4 is enhanced through increase of its lifetime, and of atmospheric abundances of ozone, stratospheric water vapor, and CO2 as a result of atmospheric chemical processes. Despite uncertainties in emission scenarios, our results provide a better understanding of the feedbacks in the atmospheric chemistry that would amplify climate warming.

  1. Atmospheric Ammonia Emissions From Operational Areas of a Dairy

    NASA Astrophysics Data System (ADS)

    Rumburg, B. P.; Mount, G. H.; Filipy, J.; Lamb, B.; Westberg, H.; Neger, M.; Yonge, D.; Johnson, K.; Kincaid, R.

    2001-12-01

    Ammonia gas is important in aerosol formation, soil acidification, aquatic eutrophication, acid rain and can damage human and animal respiratory systems. Anthropogenic emissions are approximately two-thirds of the global emissions of NH3 and agriculture is the dominant anthropogenic source. We are studying NH3 emissions from the WSU dairy located near Pullman, WA to provide a detailed emission inventory. The dairy has approximately 200 milking cows and 200 replacement heifers. The cows are housed in open air barns and the liquid waste is stored in four open air lagoons until it is applied to grass fields in the late summer. Agricultural emissions of NH3 have been measured in Europe but very few measurements have been made in the United States. Differences in feed and waste management practices between Europe and the U.S. could have a significant effect on NH3 emissions. Since NH3 is an aerosol precursor knowing emission levels is also important for the new U.S. EPA PM2.5 standard. NH3 was measured using an open short-path spectroscopic absorption near 200 nm. The instrument has a time resolution of about a second and a limiting sensitivity of a few ppb. The open path method has the benefit that it is fast, self-calibrating and does not have errors associated with NH3 adherance to inlet walls. As part of a detailed emission inventory, NH3 fluxes were determined from the milking cow stalls and of the main slurry lagoon using a SF6 tracer technique. Emissions from various parts of the dairy will be discussed.

  2. Efficient cyanide formation due to impacts of carbonaceous bodies on a planet with a nitrogen-rich atmosphere

    NASA Astrophysics Data System (ADS)

    Sugita, Seiji; Schultz, Peter H.

    2009-10-01

    Asteroidal/cometary impacts should have delivered a large amount of organic matter to Earth and other planets during the heavy bombardment period. Most of the delivered organics, however, would decompose through either severe shock heating upon impact or intense aerodynamic interaction with the ambient atmosphere. Here, we demonstrate that organics decomposed by intense aerodynamic interactions following oblique impacts will be converted to CN radicals under a wide range of redox conditions within primitive atmospheres. High-speed spectroscopic observations reveal that the nitrogen and the carbon comprising CN are derived from both the atmosphere and impact-fragmented projectile materials, respectively. The yield of CN relative to C2 (a direct vaporization product of projectile materials) increases with both impact velocity and the ratio of N2 partial pressure to the total atmospheric pressure. Such impact-driven cyanide synthesis may have significantly contributed to basic compounds (particularly nitrogen-rich ones) necessary for the origin of life.

  3. Control of Atmospheric Emissions in the Wood Pulping Industry, Volume 3.

    ERIC Educational Resources Information Center

    Hendrickson, E. R.; And Others

    Volume 3 contains chapters 9 through 13 of the final report on the control of atmospheric emissions in the wood pulping industry. These chapters deal with the following topics: sampling and analytical techniques; on-going research related to reduction of emissions; research and development recommendations; current industry investment and operating…

  4. An approach for verifying biogenic greenhouse gas emissions inventories with atmospheric CO2 concentration data

    Treesearch

    Stephen M Ogle; Kenneth Davis; Thomas Lauvaux; Andrew Schuh; Dan Cooley; Tristram O West; Linda S Heath; Natasha L Miles; Scott Richardson; F Jay Breidt; James E Smith; Jessica L McCarty; Kevin R Gurney; Pieter Tans; A Scott. Denning

    2015-01-01

    Verifying national greenhouse gas (GHG) emissions inventories is a critical step to ensure that reported emissions data to the United Nations Framework Convention on Climate Change (UNFCCC) are accurate and representative of a country's contribution to GHG concentrations in the atmosphere. Furthermore, verifying biogenic fluxes provides a check on estimated...

  5. Leaf isoprene emission rate as a function of atmospheric CO2 concentration

    USDA-ARS?s Scientific Manuscript database

    There is considerable interest in modeling isoprene emissions from terrestrial vegetation, since these emissions exert a principal control over the oxidative capacity of the troposphere, influencing the production of ozone, organic nitrates, organic acids, and affect the atmospheric lifetime of meth...

  6. Control of Atmospheric Emissions in the Wood Pulping Industry, Volume 3.

    ERIC Educational Resources Information Center

    Hendrickson, E. R.; And Others

    Volume 3 contains chapters 9 through 13 of the final report on the control of atmospheric emissions in the wood pulping industry. These chapters deal with the following topics: sampling and analytical techniques; on-going research related to reduction of emissions; research and development recommendations; current industry investment and operating…

  7. Comparison of atmospheric stability methods for calculating ammonia and methane emission rates with WindTrax

    USDA-ARS?s Scientific Manuscript database

    Inverse dispersion models are useful tools for estimating emissions from animal feeding operations, waste storage ponds, and manure application fields. Atmospheric stability is an important input parameter to such models. The objective of this study was to compare emission rates calculated with a ba...

  8. Perfluorocarbons in the global atmosphere: b) Emission estimates using inversions of atmospheric observations of tetrafluoromethane, hexafluoroethane, and octafluoropropane

    NASA Astrophysics Data System (ADS)

    Ganesan, A. L.; Muhle, J.; Rigby, M. L.; Miller, B. R.; Salameh, P. K.; Harth, C. M.; Greally, B. R.; O'Doherty, S. J.; Trudinger, C. M.; Porter, L. W.; Steele, P.; Krummel, P. B.; Petrenko, V. V.; Simmonds, P. G.; Fraser, P. J.; Prinn, R. G.; Weiss, R. F.

    2009-12-01

    The perfluorocarbons (PFCs) are long-lived potent greenhouse gases with mixing ratios that have been steadily increasing in the modern measurement record that extends from the 1970s. We present optimized emissions from 1973-present of three perfluorocarbons: tetrafluoromethane (CF4), hexafluoroethane (C2F6) and octafluoropropane (C3F8). The dominant sources of the PFCs are primary aluminum and semiconductor production. CF4 also has a significant pre-industrial abundance from the build-up of very small natural emissions. The inversions were performed with atmospheric measurements made by the Advanced Global Atmospheric Gases Experiment (AGAGE) network as well as using stored samples from the Commonwealth Scientific and Industrial Research Organization (CSIRO) Southern Hemisphere archive and from several Northern Hemisphere sources. Inverse estimates of surface flux were derived from the measurements using a discrete Kalman filter, the annual pulse method of Chen and Prinn (J. Geophys. Res., 111, D10307, doi:10.1029/2005JD006058), and a 2D 12-box chemical transport model. CF4 emissions have decreased from ~20 Gg/yr in 1981 to the present value of ~11 Gg/yr. Conversely, C2F6 and C3F8 exhibit an early increase in emissions, peaking much later around 2000 at ~3 Gg/yr and ~1 Gg/yr, respectively, and subsequently declining. The incongruity in the emission profiles is discussed in the context of different relative emissions of CF4 and the other measured PFCs from the two main sources, efforts by the aluminum industry to reduce the emission factor of CF4 (kg CF4 /ton Al), and published emission inventories. In all cases, over 90% of emissions are from the Northern Hemisphere.

  9. Atmospheric emission of polychlorinated naphthalenes from iron ore sintering processes.

    PubMed

    Liu, Guorui; Zheng, Minghui; Du, Bing; Nie, Zhiqiang; Zhang, Bing; Liu, Wenbin; Li, Cheng; Hu, Jicheng

    2012-10-01

    Iron ore sintering processes constitute significant sources of dioxins, and studies have confirmed a close correlation between polychlorinated naphthalenes (PCNs) and dioxin formation. Thus, iron ore sintering processes are thought to be a potential source of PCNs, although intensive investigations on PCN emissions from sintering processes have not been carried out. Therefore, the aim of the present study was to qualify and quantify PCN emissions from nine sintering plants operating on different industrial scales. PCN concentrations ranged from 3 to 983 ng m(-3) (0.4-23.3 pg TEQ(PCN) m(-3)) and emission factors ranged from 14 to 1749 μg t(-1) (0.5-41.5 ng TEQ(PCN) t(-1)), with a geometric mean of 84 μg t(-1) (2.1 ng TEQ(PCN) t(-1)). The estimated annual emission of PCNs from sintering processes in China was 1390 mg TEQ(PCN). These figures will assist in the development of a PCN emissions inventory. Regarding emission characteristics, PCNs mainly comprised low-chlorinated homologs. The ratios of several characteristic PCN congeners were also measured and compared with those from other sources. Taken together, these results may provide useful information for identifying the sources of PCNs produced by iron ore sintering processes.

  10. Emission Dependent on composition of Si-rich-SiNX Films obtained by PECVD

    NASA Astrophysics Data System (ADS)

    Jaramillo Gomez, J. A.; Torchynska, T. V.; Casas Espinola, J. L.; Bentosa Gutiérrez, J. A.; Khomenkova, L.; Slaoui, A.

    2017-02-01

    Silicon-rich silicon nitride films with different stoichiometry were grown on silicon substrate using the plasma-enhanced chemical vapor deposition. The excess silicon content in the films was monitored via a variation of the NH3/SiH4 gas flow ratio from 0.45 up to 1.0. Morphology and luminescence properties of the films were studied by means of atomic force microscopy (AFM) and photoluminescence (PL) methods. High-temperature annealing was employed to produce the silicon nanocrystals in the films and to enhance the photoluminescence in the range of 1.6-3.0 eV. The PL spectrum was found to be complex due to the contribution of several radiative channels in emission process. It was determined that their competition leads to the non-monotonous variation of total PL peak position with the increase of the Si excess content. It was observed that the shape of PL spectra depends on an excitation wavelength. The ways to control the PL emission is proposed based on the discussion of the PL mechanism.

  11. The role of power plant atmospheric emissions in the deposition of nitrogen to the Chesapeake Bay

    SciTech Connect

    Miller, P.E.

    1994-12-31

    The Maryland Power Plant Research Program (PPRP) has sponsored research on several aspects of atmospheric nitrogen emissions, source attribution, deposition estimation and impact assessment since the mid-eighties. The results of these studies will be presented and discussed in the context of power plant emissions control impact on nitrogen loadings to the Chesapeake Bay and watershed. Information needs with respect to power plant contribution and emission control policy will be identified and discussed from the perspective of PPRP.

  12. Quantifying Uncertainty in Daily Temporal Variations of Atmospheric NH3 Emissions Following Application of Chemical Fertilizers

    NASA Astrophysics Data System (ADS)

    Balasubramanian, S.; Koloutsou-Vakakis, S.; Rood, M. J.

    2014-12-01

    Improving modeling predictions of atmospheric particulate matter and deposition of reactive nitrogen requires representative emission inventories of precursor species, such as ammonia (NH3). Anthropogenic NH3 is primarily emitted to the atmosphere from agricultural sources (80-90%) with dominant contributions (56%) from chemical fertilizer usage (CFU) in regions like Midwest USA. Local crop management practices vary spatially and temporally, which influence regional air quality. To model the impact of CFU, NH3 emission inputs to chemical transport models are obtained from the National Emission Inventory (NEI). NH3 emissions from CFU are typically estimated by combining annual fertilizer sales data with emission factors. The Sparse Matrix Operator Kernel Emissions (SMOKE) model is used to disaggregate annual emissions to hourly scale using temporal factors. These factors are estimated by apportioning emissions within each crop season in proportion to the nitrogen applied and time-averaged to the hourly scale. Such approach does not reflect influence of CFU for different crops and local weather and soil conditions. This study provides an alternate approach for estimating temporal factors for NH3 emissions. The DeNitrification DeComposition (DNDC) model was used to estimate daily variations in NH3 emissions from CFU at 14 Central Illinois locations for 2002-2011. Weather, crop and soil data were provided as inputs. A method was developed to estimate site level CFU by combining planting and harvesting dates, nitrogen management and fertilizer sales data. DNDC results indicated that annual NH3 emissions were within ±15% of SMOKE estimates. Daily modeled emissions across 10 years followed similar distributions but varied in magnitudes within ±20%. Individual emission peaks on days after CFU were 2.5-8 times greater as compared to existing estimates from SMOKE. By identifying the episodic nature of NH3 emissions from CFU, this study is expected to provide improvements

  13. Global atmospheric emission inventory of polycyclic aromatic hydrocarbons (PAHs) for 2004

    NASA Astrophysics Data System (ADS)

    Zhang, Yanxu; Tao, Shu

    The global atmospheric emissions of the 16 polycyclic aromatic hydrocarbons (PAHs) listed as the US EPA priority pollutants were estimated using reported emission activity and emission factor data for the reference year 2004. A database for emission factors was compiled, and their geometric means and frequency distributions applied for emission calculation and uncertainty analysis, respectively. The results for 37 countries were compared with other PAH emission inventories. It was estimated that the total global atmospheric emission of these 16 PAHs in 2004 was 520 giga grams per year (Gg y -1) with biofuel (56.7%), wildfire (17.0%) and consumer product usage (6.9%) as the major sources, and China (114 Gg y -1), India (90 Gg y -1) and United States (32 Gg y -1) were the top three countries with the highest PAH emissions. The PAH sources in the individual countries varied remarkably. For example, biofuel burning was the dominant PAH source in India, wildfire emissions were the dominant PAH source in Brazil, while consumer products were the major PAH emission source in the United States. In China, in addition to biomass combustion, coke ovens were a significant source of PAHs. Globally, benzo(a)pyrene accounted for 0.05% to 2.08% of the total PAH emission, with developing countries accounting for the higher percentages. The PAH emission density varied dramatically from 0.0013 kg km -2 y in the Falkland Islands to 360 kg km -2 y in Singapore with a global mean value of 3.98 kg km -2 y. The atmospheric emission of PAHs was positively correlated to the country's gross domestic product and negatively correlated with average income. Finally, a linear bivariate regression model was developed to explain the global PAH emission data.

  14. International Global Atmospheric Chemistry Programme global emissions inventory activity: Sulfur emissions from volcanoes, current status

    SciTech Connect

    Benkovitz, C.M.

    1995-07-01

    Sulfur emissions from volcanoes are located in areas of volcanic activity, are extremely variable in time, and can be released anywhere from ground level to the stratosphere. Previous estimates of global sulfur emissions from all sources by various authors have included estimates for emissions from volcanic activity. In general, these global estimates of sulfur emissions from volcanoes are given as global totals for an ``average`` year. A project has been initiated at Brookhaven National Laboratory to compile inventories of sulfur emissions from volcanoes. In order to complement the GEIA inventories of anthropogenic sulfur emissions, which represent conditions circa specific years, sulfur emissions from volcanoes are being estimated for the years 1985 and 1990.

  15. Spatial and temporal variations in infrared emissions of the upper atmosphere. 1. Atomic oxygen (λ 63 μm) emission

    NASA Astrophysics Data System (ADS)

    Semenov, A. I.; Medvedeva, I. V.; Perminov, V. I.; Khomich, V. Yu.

    2016-09-01

    Rocket and balloon measurement data on atomic-oxygen (λ 63 µm) emission in the upper atmosphere are presented. The data from the longest (1989-2003) period of measurements of the atomic-oxygen (λ 63 µm) emission intensity obtained by spectral instruments on sounding balloons at an altitude of 38 km at midlatitudes have been systematized and analyzed. Regularities in diurnal and seasonal variations in the intensity of this emission, as well as in its relation with solar activity, have been revealed.

  16. Compilation and analyses of emissions inventories for the NOAA atmospheric chemistry project. Progress report, August 1997

    SciTech Connect

    Benkovitz, C.M.

    1997-09-01

    Global inventories of anthropogenic emissions of oxides of nitrogen for circa 1985 and 1990 and non-methane volatile organic compounds (NMVOCs) for circa 1990 have been compiled by this project. Work on the inventories has been carried out under the umbrella of the Global Emissions Inventory Activity of the International Global Atmospheric Chemistry program. Global emissions of NOx for 1985 are estimated to be 21 Tg N/yr, with approximately 84% originating in the Northern Hemisphere. The global emissions for 1990 are 31 Tg N/yr for NOx and 173 Gg NMVOC/yr. Ongoing research activities for this project continue to address emissions of both NOx and NMVOCs. Future tasks include: evaluation of more detailed regional emissions estimates and update of the default 1990 inventories with the appropriate estimates; derivation of quantitative uncertainty estimates for the emission values; and development of emissions estimates for 1995.

  17. Measurements of trace constituents from atmospheric infrared emission and absorption spectra, a feasibility study

    NASA Technical Reports Server (NTRS)

    Goldman, A.; Williams, W. J.; Murcray, D. G.

    1974-01-01

    The feasibility of detecting eight trace constituents (CH4, HCl, HF, HNO3, NH3, NO, NO2 and SO2) against the rest of the atmospheric background at various altitudes from infrared emission and absorption atmospheric spectra was studied. Line-by-line calculations and observational data were used to establish features that can be observed in the atmospheric spectrum due to each trace constituent. Model calculations were made for experimental conditions which approximately represent state of the art emission and absorption spectrometers.

  18. A comparison of state-level estimation techniques for utility atmospheric emission factors

    SciTech Connect

    Schrock, D.; Baechler, M.

    1995-10-01

    Atmospheric emission factors provide a link between the electricity saved in buildings and the associated decrease in fossil fuel use in the electric supply sector. Understanding this link is important to meet the requirements of Section 1605(b) of the Energy Policy act of 1992, which established the voluntary program for reporting reductions in greenhouse gases. As part of the development process for Section 1605(b), several national workshops were held by the US Department of Energy (DOE) and the Energy Information Administration (EIA). Workshop participants expressed the need for DOE to supply default atmospheric emission facets. Based upon the response from the workshop participants, it was decided that emission factors would be aggregated to the state level (e.g., California, Connecticut, etc.). Emission factors for electricity generation are generally quantified as a quantity of impact to an amount of fuel used to produce the emission. In the electric supply sector, factors are often expressed in units of pounds or tons of emission per megawatt-hours (MWh) of electricity produced. In this paper, the authors examine and compare the estimates from three methodologies for developing state-level emission facets. In addition, they compare the results to those obtained using emissions data calculated by the EIA. Although the examples presented in this paper depict the development of state-level factors, the same methodologies can be applied by an individual utility to generate utility-specific atmospheric emission factors.

  19. Estimating European historical production, consumption and atmospheric emissions of decabromodiphenyl ether.

    PubMed

    Earnshaw, Mark R; Jones, Kevin C; Sweetman, Andy J

    2013-03-01

    A European scale production, consumption and environmental emissions inventory is produced for decabromodiphenyl ether (DecaBDE) for the period 1970-2020. A dynamic substance flow analysis model of DecaBDE is developed and emission of the main congener, BDE-209, to environmental compartments is estimated. From 1970 to 2010, it is estimated that a total of 185,000-250,000 tonnes of DecaBDE was consumed in Europe. Consumption peaked in the late 1990s at approximately 9,000 tonnes/year and has declined by ~30% in 2010. Predicted BDE-209 atmospheric emissions peak in 2004 at 10 tonnes/year. The waste management phase of the BDE-209 life cycle is responsible for the majority of atmospheric emissions via volatilisation and particle bound emissions from landfills, whilst leakage from Sewerage systems is the major source of emissions to the hydrosphere. Use of sewage sludge from wastewater treatment works as an agricultural fertiliser is the most important pathway of BDE-209 to soil. Although DecaBDE consumption has declined in recent years, the stock in use for 2010 remains considerable (60,000 tonnes) and is likely to act as a source of atmospheric emissions for several decades. Uncertainties exist in these estimations and more field or experimental data is needed to clarify the significance of certain emission pathways, in particular, emissions from landfill sites.

  20. Evaluation of inorganic zinc-rich primers using Electrochemical Impedance Spectroscopy (EIS) in combination with atmospheric exposure

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.

    1994-01-01

    This investigation explored the use of Electrochemical Impedance Spectroscopy (EIS) in combination with atmospheric exposure as a short term method for analyzing the performance of twenty-one commercially available zinc-rich primers. The twenty-one zinc-rich primers were: Carboline CZ-11, Ameron Devoe-Marine Catha-Coat 304, Briner V-65, Ameron D-21-9, Sherwin Williams Zinc Clad II, Carboline CZ-D7, Ameron D-4, Dupont Ganicin 347WB, Porter TQ-4374H, Inorganic Coatings IC-531, Subox Galvanox IV, Southern Coatings Chemtec 600, GLidden Glidzinc 5530, Byco SP-101, Tnemec 90E-75, Devoe Catha-Coat 302H, Glidden Glidzinc 5536, Koppers 701, Ameron D-21-5, Coronado 935-152, and Subox Galvanox V. Data were also collected on galvanized steel for comparison purposes. A library of Bode magnitude plots was generated for each coating including curves for the initial time and after each week of atmospheric exposure at the Beach Corrosion Test site near the Space Shuttle launch pad at the Kennedy Space Center for up to four weeks. Subsequent measurements were collected after 8 weeks and after one year of atmospheric exposure. Analysis of the impedance data was performed with the purpose of identifying parameters that could be used to predict the long-term performance of zinc-rich primers. It has been shown that there is a correlation between the long-term performance of zinc-rich primers and several parameters obtained from EIS measurements in combination with atmospheric exposure. The equivalent circuit R2(R2C(R3W)) provided a satisfactory fit for the EIS data. The corrosion potential and the R2 resistance are parameters indicative of the galvanic mechanism of protection. The capacitance of the coating is related to the barrier mechanism of protection.

  1. Extractive probe/TDLAS measurements of acetylene in atmospheric-pressure fuel-rich premixed methane/air flames

    SciTech Connect

    Gersen, S.; Mokhov, A.V.; Levinsky, H.B.

    2005-11-01

    The profiles of C{sub 2}H{sub 2} mole fractions were measured in flat atmospheric-pressure rich-premixed methane/air flames using microprobe gas sampling followed by tunable diode laser absorption spectroscopy (TDLAS), and compared the results with predictions of one-dimensional flame calculations. Acetylene concentrations are also determined by spontaneous Raman scattering to quantify possible uncertainties due to chemical reactions on the probe surface or acceleration of the combustion products into the probe.

  2. Atmospheric polycyclic aromatic hydrocarbons: Source attribution, emission factors and regulation

    NASA Astrophysics Data System (ADS)

    Ravindra, Khaiwal; Sokhi, Ranjeet; Van Grieken, René

    There is an increasing concern about the occurrence of polycyclic aromatic hydrocarbons (PAHs) in the environment as they are ubiquitous in ambient air and some of them are among the strongest known carcinogens. PAHs and their derivatives are produced by the incomplete combustion of organic material arising, partly, from natural combustion such as forest and volcanic eruption, but with the majority due to anthropogenic emissions. The PAH concentration varies significantly in various rural and urban environments and is mainly influenced by vehicular and domestic emissions. The review serves as a database to identify and characterize the emission sources of PAHs and hence various approaches including diagnostic ratio (DR) and principal component analysis (PCA) are discussed in detail. These approaches allow individual PAHs to be associated with their origin sources. The factors that effect PAH emission and estimated emission rate are also discussed in this paper. Although the levels of low molecular weight PAHs are high in vapor phase, most of the probable human carcinogenic PAHs are found to be associated with particulate matter, especially in fine mode particles in ambient air. Many countries have proposed a non-mandatory concentration limit for PAHs, whereas the health risk studies conducted in relation to PAH exposure, urge that these pollutants should be given a high priority when considering air quality management and reduction of impacts.

  3. Separation of Atmospheric and Surface Spectral Features in Mars Global Surveyor Thermal Emission Spectrometer (TES) Spectra

    NASA Technical Reports Server (NTRS)

    Smith, Michael D.; Bandfield, Joshua L.; Christensen, Philip R.

    2000-01-01

    We present two algorithms for the separation of spectral features caused by atmospheric and surface components in Thermal Emission Spectrometer (TES) data. One algorithm uses radiative transfer and successive least squares fitting to find spectral shapes first for atmospheric dust, then for water-ice aerosols, and then, finally, for surface emissivity. A second independent algorithm uses a combination of factor analysis, target transformation, and deconvolution to simultaneously find dust, water ice, and surface emissivity spectral shapes. Both algorithms have been applied to TES spectra, and both find very similar atmospheric and surface spectral shapes. For TES spectra taken during aerobraking and science phasing periods in nadir-geometry these two algorithms give meaningful and usable surface emissivity spectra that can be used for mineralogical identification.

  4. Mercury enrichment and its effects on atmospheric emissions in cement plants of China

    NASA Astrophysics Data System (ADS)

    Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Wu, Qingru; Hao, Jiming

    2014-08-01

    The cement industry is one of the most significant anthropogenic sources of atmospheric mercury emissions worldwide. In this study of three typical Chinese cement plants, mercury in kiln flue gas was sampled using the Ontario Hydro Method (OHM), and solid samples were analyzed. Particulate matter recycling, preheating of raw materials, and the use of coal and flue gas desulfurization derived gypsum contributed to emissions of Hg in the air and to accumulation in cement. Over 90% of the mercury input was emitted into the atmosphere. Mercury emission factors were 0.044-0.072 g/t clinker for the test plants. The major species emitted into the atmosphere from cement plants is oxidized mercury, accounting for 61%-91% of the total mercury in flue gas. The results of this study help improve the accuracy of the mercury emission inventory in China and provide useful information for developing mercury controls.

  5. Microwave emission and scattering from Earth surface and atmosphere

    NASA Technical Reports Server (NTRS)

    Kong, J. A.; Lee, M. C.

    1986-01-01

    Nonlinear Electromagnetic (EM) wave interactions with the upper atmosphere were investigated during the period 15 December 1985 to 15 June 1986. Topics discussed include: the simultaneous excitation of ionospheric density irregularities and Earth's magnetic field fluctuations; the electron acceleration by Langmuir wave turbulence; and the occurrence of artificial spread F. The role of thermal effects in generating ionospheric irregularities by Whistler waves, intense Quasi-DC electric fields, atmospheric gravity waves, and electrojets was investigated. A model was developed to explain the discrete spectrum of the resonant ultralow frequency (ULF) waves that are commonly observed in the magnetosphere.

  6. Evidence from massive siderite beds for a CO2-rich atmosphere before approximately 1.8 billion years ago

    NASA Technical Reports Server (NTRS)

    Ohmoto, Hiroshi; Watanabe, Yumiko; Kumazawa, Kazumasa

    2004-01-01

    It is generally thought that, in order to compensate for lower solar flux and maintain liquid oceans on the early Earth, methane must have been an important greenhouse gas before approximately 2.2 billion years (Gyr) ago. This is based upon a simple thermodynamic calculation that relates the absence of siderite (FeCO3) in some pre-2.2-Gyr palaeosols to atmospheric CO2 concentrations that would have been too low to have provided the necessary greenhouse effect. Using multi-dimensional thermodynamic analyses and geological evidence, we show here that the absence of siderite in palaeosols does not constrain atmospheric CO2 concentrations. Siderite is absent in many palaeosols (both pre- and post-2.2-Gyr in age) because the O2 concentrations and pH conditions in well-aerated soils have favoured the formation of ferric (Fe3+)-rich minerals, such as goethite, rather than siderite. Siderite, however, has formed throughout geological history in subsurface environments, such as euxinic seas, where anaerobic organisms created H2-rich conditions. The abundance of large, massive siderite-rich beds in pre-1.8-Gyr sedimentary sequences and their carbon isotope ratios indicate that the atmospheric CO2 concentration was more than 100 times greater than today, causing the rain and ocean waters to be more acidic than today. We therefore conclude that CO2 alone (without a significant contribution from methane) could have provided the necessary greenhouse effect to maintain liquid oceans on the early Earth.

  7. Global carbon dioxide emission to the atmosphere by volcanoes

    SciTech Connect

    Williams, S.N.; Schaefer, S.J. ); Calvache V., M.L. Observatorio Vulcanologico de Colombia, Pasto ); Lopez, D. )

    1992-04-01

    Global emission of carbon dioxide by subaerial volcanoes is calculated, using CO{sub 2}/SO{sub 2} from volcanic gas analyses and SO{sub 2} flux, to be 34 {plus minus} 24 {times} 10{sup 12} g CO{sub 2}/yr from passive degassing and 31 {plus minus} 22 {times} 10{sup 12} g CO{sub 2}/yr from eruptions. Volcanic CO{sub 2} presently represents only 0.22% of anthropogenic emissions but may have contributed to significant greenhouse' effects at times in Earth history. Models of climate response to CO{sub 2} increases may be tested against geological data.

  8. Measuring the spectral emissivity of thermal protection materials during atmospheric reentry simulation

    NASA Technical Reports Server (NTRS)

    Marble, Elizabeth

    1996-01-01

    Hypersonic spacecraft reentering the earth's atmosphere encounter extreme heat due to atmospheric friction. Thermal Protection System (TPS) materials shield the craft from this searing heat, which can reach temperatures of 2900 F. Various thermophysical and optical properties of TPS materials are tested at the Johnson Space Center Atmospheric Reentry Materials and Structures Evaluation Facility, which has the capability to simulate critical environmental conditions associated with entry into the earth's atmosphere. Emissivity is an optical property that determines how well a material will reradiate incident heat back into the atmosphere upon reentry, thus protecting the spacecraft from the intense frictional heat. This report describes a method of measuring TPS emissivities using the SR5000 Scanning Spectroradiometer, and includes system characteristics, sample data, and operational procedures developed for arc-jet applications.

  9. Effects of nitrogen and phosphorus additions on nitrous oxide emission in a nitrogen-rich and two nitrogen-limited tropical forests

    NASA Astrophysics Data System (ADS)

    Zheng, Mianhai; Zhang, Tao; Liu, Lei; Zhu, Weixing; Zhang, Wei; Mo, Jiangming

    2016-06-01

    Nitrogen (N) deposition is generally considered to increase soil nitrous oxide (N2O) emission in N-rich forests. In many tropical forests, however, elevated N deposition has caused soil N enrichment and further phosphorus (P) deficiency, and the interaction of N and P to control soil N2O emission remains poorly understood, particularly in forests with different soil N status. In this study, we examined the effects of N and P additions on soil N2O emission in an N-rich old-growth forest and two N-limited younger forests (a mixed and a pine forest) in southern China to test the following hypotheses: (1) soil N2O emission is the highest in old-growth forest due to the N-rich soil; (2) N addition increases N2O emission more in the old-growth forest than in the two younger forests; (3) P addition decreases N2O emission more in the old-growth forest than in the two younger forests; and (4) P addition alleviates the stimulation of N2O emission by N addition. The following four treatments were established in each forest: Control, N addition (150 kg N ha-1 yr-1), P addition (150 kg P ha-1 yr-1), and NP addition (150 kg N ha-1 yr-1 plus 150 kg P ha-1 yr-1). From February 2007 to October 2009, monthly quantification of soil N2O emission was performed using static chamber and gas chromatography techniques. Mean N2O emission was shown to be significantly higher in the old-growth forest (13.9 ± 0.7 µg N2O-N m-2 h-1) than in the mixed (9.9 ± 0.4 µg N2O-N m-2 h-1) or pine (10.8 ± 0.5 µg N2O-N m-2 h-1) forests, with no significant difference between the latter two. N addition significantly increased N2O emission in the old-growth forest but not in the two younger forests. However, both P and NP addition had no significant effect on N2O emission in all three forests, suggesting that P addition alleviated the stimulation of N2O emission by N addition in the old-growth forest. Although P fertilization may alleviate the stimulated effects of atmospheric N deposition on N2O

  10. An approach for verifying biogenic greenhouse gas emissions inventories with atmospheric CO2 concentration data

    NASA Astrophysics Data System (ADS)

    Ogle, Stephen M.; Davis, Kenneth; Lauvaux, Thomas; Schuh, Andrew; Cooley, Dan; West, Tristram O.; Heath, Linda S.; Miles, Natasha L.; Richardson, Scott; Breidt, F. Jay; Smith, James E.; McCarty, Jessica L.; Gurney, Kevin R.; Tans, Pieter; Denning, A. Scott

    2015-03-01

    Verifying national greenhouse gas (GHG) emissions inventories is a critical step to ensure that reported emissions data to the United Nations Framework Convention on Climate Change (UNFCCC) are accurate and representative of a country’s contribution to GHG concentrations in the atmosphere. Furthermore, verifying biogenic fluxes provides a check on estimated emissions associated with managing lands for carbon sequestration and other activities, which often have large uncertainties. We report here on the challenges and results associated with a case study using atmospheric measurements of CO2 concentrations and inverse modeling to verify nationally-reported biogenic CO2 emissions. The biogenic CO2 emissions inventory was compiled for the Mid-Continent region of United States based on methods and data used by the US government for reporting to the UNFCCC, along with additional sources and sinks to produce a full carbon balance. The biogenic emissions inventory produced an estimated flux of -408 ± 136 Tg CO2 for the entire study region, which was not statistically different from the biogenic flux of -478 ± 146 Tg CO2 that was estimated using the atmospheric CO2 concentration data. At sub-regional scales, the spatial density of atmospheric observations did not appear sufficient to verify emissions in general. However, a difference between the inventory and inversion results was found in one isolated area of West-central Wisconsin. This part of the region is dominated by forestlands, suggesting that further investigation may be warranted into the forest C stock or harvested wood product data from this portion of the study area. The results suggest that observations of atmospheric CO2 concentration data and inverse modeling could be used to verify biogenic emissions, and provide more confidence in biogenic GHG emissions reporting to the UNFCCC.

  11. Assessment of atmospheric mercury emission reduction measures relevant for application in Poland

    SciTech Connect

    Hlawiczka, S.; Fudala, J.

    2008-03-15

    Fuel combustion for heat and power generation, together with cement production, were the most significant sources of anthropogenic atmospheric mercury emission in Poland in 2003, with 57 and 27% of Hg emission, respectively. It was found that in Poland, Hg emission reduction measures need to be focused on the energy generation sector. Sorbent injection upstream of an electrostatic precipitator or fabric filter, mercury oxidation upstream of a wet or dry flue gas desulphurisation installation, together with Hg capture on sorbents, should be considered as priority in Polish conditions. This refers mainly to fuel combustion processes but also to the production of cement. For economic reasons it seems advisable that, apart from activated carbons as sorbents, application of zeolites obtained from power plant fly ash should also be considered. Application of primary methods seems to be very promising in Polish conditions, although they should be considered rather as an additional option apart from sorbent injection as the best option. Switching from coal to liquid and gaseous fuels shows the highest potential for reducing Hg emission. For chlorine production using the mercury cell electrolysis method, strict monitoring of Hg emissions and good housekeeping of Hg releasing processes seems a promising approach, but the main activity should focus on changing mercury-based technologies into membrane cell methods. Emission abatement potential for the atmospheric mercury in Poland has been roughly assessed, showing that in perspective of 2015, the emission could be reduced to about 25% of the anthropogenic atmospheric Hg emission in 2003.

  12. Observed decrease in atmospheric mercury explained by global decline in anthropogenic emissions

    PubMed Central

    Zhang, Yanxu; Jacob, Daniel J.; Horowitz, Hannah M.; Chen, Long; Amos, Helen M.; Krabbenhoft, David P.; Slemr, Franz; St. Louis, Vincent L.; Sunderland, Elsie M.

    2016-01-01

    Observations of elemental mercury (Hg0) at sites in North America and Europe show large decreases (∼1–2% y−1) from 1990 to present. Observations in background northern hemisphere air, including Mauna Loa Observatory (Hawaii) and CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) aircraft flights, show weaker decreases (<1% y−1). These decreases are inconsistent with current global emission inventories indicating flat or increasing emissions over that period. However, the inventories have three major flaws: (i) they do not account for the decline in atmospheric release of Hg from commercial products; (ii) they are biased in their estimate of artisanal and small-scale gold mining emissions; and (iii) they do not properly account for the change in Hg0/HgII speciation of emissions from coal-fired utilities after implementation of emission controls targeted at SO2 and NOx. We construct an improved global emission inventory for the period 1990 to 2010 accounting for the above factors and find a 20% decrease in total Hg emissions and a 30% decrease in anthropogenic Hg0 emissions, with much larger decreases in North America and Europe offsetting the effect of increasing emissions in Asia. Implementation of our inventory in a global 3D atmospheric Hg simulation [GEOS-Chem (Goddard Earth Observing System-Chemistry)] coupled to land and ocean reservoirs reproduces the observed large-scale trends in atmospheric Hg0 concentrations and in HgII wet deposition. The large trends observed in North America and Europe reflect the phase-out of Hg from commercial products as well as the cobenefit from SO2 and NOx emission controls on coal-fired utilities. PMID:26729866

  13. Observed decrease in atmospheric mercury explained by global decline in anthropogenic emissions.

    PubMed

    Zhang, Yanxu; Jacob, Daniel J; Horowitz, Hannah M; Chen, Long; Amos, Helen M; Krabbenhoft, David P; Slemr, Franz; St Louis, Vincent L; Sunderland, Elsie M

    2016-01-19

    Observations of elemental mercury (Hg(0)) at sites in North America and Europe show large decreases (∼ 1-2% y(-1)) from 1990 to present. Observations in background northern hemisphere air, including Mauna Loa Observatory (Hawaii) and CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) aircraft flights, show weaker decreases (<1% y(-1)). These decreases are inconsistent with current global emission inventories indicating flat or increasing emissions over that period. However, the inventories have three major flaws: (i) they do not account for the decline in atmospheric release of Hg from commercial products; (ii) they are biased in their estimate of artisanal and small-scale gold mining emissions; and (iii) they do not properly account for the change in Hg(0)/Hg(II) speciation of emissions from coal-fired utilities after implementation of emission controls targeted at SO2 and NOx. We construct an improved global emission inventory for the period 1990 to 2010 accounting for the above factors and find a 20% decrease in total Hg emissions and a 30% decrease in anthropogenic Hg(0) emissions, with much larger decreases in North America and Europe offsetting the effect of increasing emissions in Asia. Implementation of our inventory in a global 3D atmospheric Hg simulation [GEOS-Chem (Goddard Earth Observing System-Chemistry)] coupled to land and ocean reservoirs reproduces the observed large-scale trends in atmospheric Hg(0) concentrations and in Hg(II) wet deposition. The large trends observed in North America and Europe reflect the phase-out of Hg from commercial products as well as the cobenefit from SO2 and NOx emission controls on coal-fired utilities.

  14. LUNG TUMOR KRAS AND TP53 MUTATIONS IN NONSMOKERS REFLECT EXPOSURE TO PAH-RICH COAL COMBUSTION EMISSIONS

    EPA Science Inventory

    Lung Tumor KRAS and TP53 Mutations in Nonsmokers Reflect Exposure to PAH-Rich
    Coal Combustion Emissions

    Use of smoky coal in unvented homes in Xuan Wei County, Yunnan Province, China, is associated with lung cancer among nonsmoking females. Such women have the highest...

  15. LUNG TUMOR KRAS AND TP53 MUTATIONS IN NONSMOKERS REFLECT EXPOSURE TO PAH-RICH COAL COMBUSTION EMISSIONS

    EPA Science Inventory

    Lung Tumor KRAS and TP53 Mutations in Nonsmokers Reflect Exposure to PAH-Rich
    Coal Combustion Emissions

    Use of smoky coal in unvented homes in Xuan Wei County, Yunnan Province, China, is associated with lung cancer among nonsmoking females. Such women have the highest...

  16. Direct oceanic emissions unlikely to account for the missing source of atmospheric carbonyl sulfide

    NASA Astrophysics Data System (ADS)

    Lennartz, Sinikka T.; Marandino, Christa A.; von Hobe, Marc; Cortes, Pau; Quack, Birgit; Simo, Rafel; Booge, Dennis; Pozzer, Andrea; Steinhoff, Tobias; Arevalo-Martinez, Damian L.; Kloss, Corinna; Bracher, Astrid; Röttgers, Rüdiger; Atlas, Elliot; Krüger, Kirstin

    2017-01-01

    The climate active trace-gas carbonyl sulfide (OCS) is the most abundant sulfur gas in the atmosphere. A missing source in its atmospheric budget is currently suggested, resulting from an upward revision of the vegetation sink. Tropical oceanic emissions have been proposed to close the resulting gap in the atmospheric budget. We present a bottom-up approach including (i) new observations of OCS in surface waters of the tropical Atlantic, Pacific and Indian oceans and (ii) a further improved global box model to show that direct OCS emissions are unlikely to account for the missing source. The box model suggests an undersaturation of the surface water with respect to OCS integrated over the entire tropical ocean area and, further, global annual direct emissions of OCS well below that suggested by top-down estimates. In addition, we discuss the potential of indirect emission from CS2 and dimethylsulfide (DMS) to account for the gap in the atmospheric budget. This bottom-up estimate of oceanic emissions has implications for using OCS as a proxy for global terrestrial CO2 uptake, which is currently impeded by the inadequate quantification of atmospheric OCS sources and sinks.

  17. Transmission And Emission Spectroscopy Of Exoplanetary Atmospheres From The Ground

    NASA Astrophysics Data System (ADS)

    Waldmann, Ingo

    2010-01-01

    It has been shown in recent years with great success that spectroscopy of exoplanetary atmospheres is feasible using space based observatories such as the HST and Spitzer. However, with the end of the Spitzer cold-phase, space based observations in the near to mid infra-red are limited, which will remain true until the the onset of the JWST. The importance of developing methods of ground based spectroscopic analysis of known hot Jupiters is therefore apparent. In the past, various groups have attempted exoplanetary spectroscopy using ground based facilities and various techniques. Here I like to present some preliminary results on a new attempt of the ground based efforts and discuss the feasibility of ground-based spectroscopy of exoplanetary atmospheres. This project is under the supervision of Giovanna Tinetti (University College London) and in collaboration with J. P. Beaulieu (Institut d'Astrophysique de Paris), Mark Swain and Pieter Deroo (Jet Propulsion Laboratory, Caltech).

  18. Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century.

    PubMed

    Graven, Heather D

    2015-08-04

    Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon ((14)C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio (14)C/C in atmospheric CO2 (Δ(14)CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ(14)CO2 because fossil fuels have lost all (14)C from radioactive decay. Simulations of Δ(14)CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ(14)CO2 near the preindustrial level of 0‰ through 2100, whereas "business-as-usual" emissions will reduce Δ(14)CO2 to -250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial "aging" of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old.

  19. Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century

    PubMed Central

    Graven, Heather D.

    2015-01-01

    Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon (14C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio 14C/C in atmospheric CO2 (Δ14CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ14CO2 because fossil fuels have lost all 14C from radioactive decay. Simulations of Δ14CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ14CO2 near the preindustrial level of 0‰ through 2100, whereas “business-as-usual” emissions will reduce Δ14CO2 to −250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial “aging” of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old. PMID:26195757

  20. Experimental investigation into infrasonic emissions from atmospheric turbulence.

    PubMed

    Shams, Qamar A; Zuckerwar, Allan J; Burkett, Cecil G; Weistroffer, George R; Hugo, Derek R

    2013-03-01

    Clear air turbulence (CAT) is the leading cause of in-flight injuries and in severe cases can result in fatalities. The purpose of this work is to design and develop an infrasonic array network for early warning of clear air turbulence. The infrasonic system consists of an infrasonic three-microphone array, compact windscreens, and data management system. Past experimental efforts to detect acoustic emissions from CAT have been limited. An array of three infrasonic microphones, operating in the field at NASA Langley Research Center, on several occasions received signals interpreted as infrasonic emissions from CAT. Following comparison with current lidar and other past methods, the principle of operation, the experimental methods, and experimental data are presented for case studies and confirmed by pilot reports. The power spectral density of the received signals was found to fit a power law having an exponent of -6 to -7, which is found to be characteristics of infrasonic emissions from CAT, in contrast to findings of the past.

  1. Atmospheric emissions from a passenger ferry with selective catalytic reduction.

    PubMed

    Nuszkowski, John; Clark, Nigel N; Spencer, Thomas K; Carder, Daniel K; Gautam, Mridul; Balon, Thomas H; Moynihan, Paul J

    2009-01-01

    The two main propulsion engines on Staten Island Ferry Alice Austen (Caterpillar 3516A, 1550 hp each) were fitted with selective catalytic reduction (SCR) aftertreatment technology to reduce emissions of oxides of nitrogen (NOx). After the installation of the SCR system, emissions from the ferry were characterized both pre- and post-aftertreatment. Prior research has shown that the ferry operates in four modes, namely idle, acceleration, cruise, and maneuvering modes. Emissions were measured for both engines (designated NY and SI) and for travel in both directions between Manhattan and Staten Island. The emissions characterization used an analyzer system, a data logger, and a filter-based particulate matter (PM) measurement system. The measurement of NOx, carbon monoxide (CO), and carbon dioxide (CO2) were based on federal reference methods. With the existing control strategy for the SCR urea injection, the SCR provided approximately 64% reduction of NOx for engine NY and 36% reduction for engine SI for a complete round trip with less than 6.5 parts per million by volume (ppmv) of ammonia slip during urea injection. Average reductions during the cruise mode were 75% for engine NY and 47% for engine SI, which was operating differently than engine NY. Reductions for the cruise mode during urea injection typically exceeded 94% from both engines, but urea was injected only when the catalyst temperature reached a 300 degrees C threshold pre- and postcatalyst. Data analysis showed a total NOx mass emission split with 80% produced during cruise, and the remaining 20% spread across idle, acceleration, and maneuvering. Examination of continuous NOx data showed that higher reductions of NOx could be achieved on both engines by initiating the urea injection at an earlier point (lower exhaust temperature) in the acceleration and cruise modes of operation. The oxidation catalyst reduced the CO production 94% for engine NY and 82% for engine SI, although the high CO levels

  2. Atmospheric Modeling and Verification of Point Source Fossil Fuel CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Keller, E. D.; Turnbull, J. C.; Baisden, W. T.; Brailsford, G. W.; Bromley, T.; Norris, M. W.; Zondervan, A.

    2014-12-01

    Emissions from large point sources (electricity generation and large-scale industry) of fossil fuel CO2 (CO2ff) emissions are currently determined from self-reported "bottom-up" inventory data, with an uncertainty of about 20% for individual power plants. As the world moves towards a regulatory environment, there is a need for independent, objective measurements of these emissions both to improve the accuracy of and to verify the reported amounts. "Top-down" atmospheric methods have the potential to independently constrain point source emissions, combining observations with atmospheric transport modeling to derive emission estimates. We use the Kapuni Gas Treatment Plant to examine methodologies and model sensitivities for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes and vents CO2 from locally extracted natural gas at a rate of ~0.1 Tg carbon per year. We measured the CO2ff content in three different types of observations: air samples collected in flasks over a period of a few minutes, sodium hydroxide solution exposed the atmosphere, and grass samples from the surrounding farmland, the latter two representing ~1 week integrated averages. We use the WindTrax Lagrangian plume dispersion model to compare these atmospheric observations with "expected" values given the emissions reported by the Kapuni plant. The model has difficulty accurately capturing the short-term variability in the flask samples but does well in representing the longer-term averages from grass samples, suggesting that passive integrated-sampling methods have the potential to monitor long-term emissions. Our results indicate that using this method, point source emissions can be verified to within about 30%. Further improvements in atmospheric transport modelling are needed to reduce uncertainties. In view of this, we discuss model strengths and weaknesses and explore model sensitivity to meteorological conditions

  3. Methane emission from flooded soils - from microorganisms to the atmosphere

    NASA Astrophysics Data System (ADS)

    Conrad, Ralf

    2016-04-01

    Methane is an important greenhouse gas that is affected by anthropogenic activity. The annual budget of atmospheric methane, which is about 600 million tons, is by more than 75% produced by methanogenic archaea. These archaea are the end-members of a microbial community that degrades organic matter under anaerobic conditions. Flooded rice fields constitute a major source (about 10%) of atmospheric methane. After flooding of soil, anaerobic processes are initiated, finally resulting in the disproportionation of organic matter to carbon dioxide and methane. This process occurs in the bulk soil, on decaying organic debris and in the rhizosphere. The produced methane is mostly ventilated through the plant vascular system into the atmosphere. This system also allows the diffusion of oxygen into the rizosphere, where part of the produced methane is oxidized by aerobic methanotrophic bacteria. More than 50% of the methane production is derived from plant photosynthetic products and is formed on the root surface. Methanocellales are an important group of methanogenic archaea colonizing rice roots. Soils lacking this group seem to result in reduced root colonization and methane production. In rice soil methane is produced by two major paths of methanogenesis, the hydrogenotrophic one reducing carbon dioxide to methane, and the aceticlastic one disproportionating acetate to methane and carbon dioxide. Theoretically, at least two third of the methane should be produced by aceticlastic and the rest by hydrogenotrophic methanogenesis. In nature, however, the exact contribution of the two paths can vary from zero to 100%. Several environmental factors, such as temperature and quality of organic matter affect the path of methane production. The impact of these factors on the composition and activity of the environmental methanogenic microbial community will be discussed.

  4. Using box models to quantify zonal distributions and emissions of halocarbons in the background atmosphere.

    NASA Astrophysics Data System (ADS)

    Elkins, J. W.; Nance, J. D.; Dutton, G. S.; Montzka, S. A.; Hall, B. D.; Miller, B.; Butler, J. H.; Mondeel, D. J.; Siso, C.; Moore, F. L.; Hintsa, E. J.; Wofsy, S. C.; Rigby, M. L.

    2015-12-01

    The Halocarbons and other Atmospheric Trace Species (HATS) of NOAA's Global Monitoring Division started measurements of the major chlorofluorocarbons and nitrous oxide in 1977 from flask samples collected at five remote sites around the world. Our program has expanded to over 40 compounds at twelve sites, which includes six in situ instruments and twelve flask sites. The Montreal Protocol for Substances that Deplete the Ozone Layer and its subsequent amendments has helped to decrease the concentrations of many of the ozone depleting compounds in the atmosphere. Our goal is to provide zonal emission estimates for these trace gases from multi-box models and their estimated atmospheric lifetimes in this presentation and make the emission values available on our web site. We plan to use our airborne measurements to calibrate the exchange times between the boxes for 5-box and 12-box models using sulfur hexafluoride where emissions are better understood.

  5. Balloon-borne measurements of the atmospheric emission near 94 GHz

    NASA Astrophysics Data System (ADS)

    Mandolesi, N.; Attolini, M. R.; Burigana, C.; Memmo, A.; Morigi, G.; Ventura, G.; Bersanelli, M.; Danese, L.; Weinreb, S.; Kane, B.; Partridge, B.

    1998-01-01

    We report on a balloon-borne experiment to measure high altitude atmospheric emission in the 90 GHz spectral window. The experiment was carried out with a monolithic microwave integrated circuit (MMIC) Dicke-switched radiometer based on high electron mobility transistor (HEMT) low noise amplifiers. The instrument broad bandpass (87-101 GHz) includes strong ozone lines. The atmospheric emission profile was measured from 6 to 15 km altitude. In addition, zenith-scan measurements at about 38 km altitude have been obtained, yielding an atmospheric antenna temperature TA,atm = 15+/-6 mK. The results are in good agreement with model predictions which take into account the contribution of O3 spectral lines. Ozone emission contributes significantly to the signal of balloon-borne Cosmic Microwave Background experiments unless the instrument bands are carefully selected.

  6. Future trends of global atmospheric antimony emissions from anthropogenic activities until 2050

    NASA Astrophysics Data System (ADS)

    Zhou, Junrui; Tian, Hezhong; Zhu, Chuanyong; Hao, Jiming; Gao, Jiajia; Wang, Yong; Xue, Yifeng; Hua, Shenbin; Wang, Kun

    2015-11-01

    This paper presents the scenario forecast of global atmospheric antimony (Sb) emissions from anthropogenic activities till 2050. The projection scenarios are built based on the comprehensive global antimony emission inventory for the period 1995-2010 which is reported in our previous study. Three scenarios are set up to investigate the future changes of global antimony emissions as well as their source and region contribution characteristics. Trends of activity levels specified as 5 primary source categories are projected by combining the historical trend extrapolation with EIA International energy outlook 2013, while the source-specific dynamic emission factors are determined by applying transformed normal distribution functions. If no major changes in the efficiency of emission control are introduced and keep current air quality legislations (Current Legislation scenario), global antimony emissions will increase by a factor of 2 between 2010 and 2050. The largest increase in Sb emissions is projected from Asia due to large volume of nonferrous metals production and waste incineration. In case of enforcing the pollutant emission standards (Strengthened Control scenario), global antimony emissions in 2050 will stabilize with that of 2010. Moreover, we can anticipate further declines in Sb emissions for all continents with the best emission control performances (Maximum Feasible Technological Reduction scenario). Future antimony emissions from the top 10 largest emitting countries have also been calculated and source category contributions of increasing emissions of these countries present significant diversity. Furthermore, global emission projections in 2050 are distributed within a 1° × 1°latitude/longitude grid. East Asia, Western Europe and North America present remarkable differences in emission intensity under the three scenarios, which implies that source-and-country specific control measures are necessary to be implemented for abating Sb emissions from

  7. Preventing atmospheric ammonia emissions: A generator/regulator solution

    SciTech Connect

    Breed, C.E.; Holt, M.T.

    1994-10-01

    During most of the 60 years that TVA has been in existence, the research center at Muscle Shoals, Alabama, NERC, was charged with supporting the regional and national agribusiness industry. One aspect of this support was strong emphasis on fertilizer process and product development. One such product developed at the center was a liquid fertilizer with a grade of 10-34-0 (N-P{sub 2}0{sub 5}-K{sub 2}0). The process was profitable and easy to operate, the product was well accepted by both farmers and dealers, and 10-34-0 became the premium phosphate fertilizer used in the United States. Approximately 120 to 130 of these type units have been constructed and operated in the United States in the last 20 years. During that time, the process design has remained essentially unchanged. The direct contact between the hot fertilizer product and the air results in some free ammonia being stripped from the product and emitted from the top of the cooling tower. At the time most of the plants were constructed, there was little concern over these losses because (1) there were very few regulations dealing with ammonia and (2) most of the plants were originally built and operated in rural areas away from population centers and emissions that occurred went essentially unnoticed. However, as a result of this study, process changes that can reduce ammonia, as well as fluoride and particulate emissions have been identified and mad available to generators. In addition a potential process for the total elimination of emissions has been developed and made available on a trial basis.

  8. Atmospheric emissions from the Windscale accident of October 1957

    NASA Astrophysics Data System (ADS)

    Garland, J. A.; Wakeford, R.

    Although it occurred nearly 50 years ago, the nuclear reactor fire of October 1957 at Windscale Works, Sellafield, England, continues to attract interest. Several attempts have been made to quantify the releases of radionuclides and their radiological consequences, but additional information and a re-analysis of meteorological data encourage a further examination of emissions. The limited instrumentation of the reactor provided little relevant information and, as in previous estimates, the discharges are deduced from environmental evidence, but here the recent meteorological analysis is used. The interpretation of the meteorological and environmental evidence requires both timing and quantity of the emitted radionuclides to be considered together. Significant fission product emission continued from about 15:00 or 16:00 on 10 October 1957 until noon the following day. There were two main peaks in discharge rate, during the evening and early hours and from roughly 06:00 until 10:30, and the amounts emitted during each of these periods were probably comparable. Iodine-131 ( 131I), caesium-137 ( 137Cs) and polonium-210 ( 210Po) activities dominated the radioactive emissions and there is sufficient environmental evidence for releases of these radionuclides to be estimated within a factor of about two. (Some additional 131I may have escaped in a chemical form that was not included in the estimate, but it appears likely that the fraction was small.) There is evidence that the plume extended further east than accepted in previous assessments and the estimates of quantities emitted have been increased to allow for this. For other radionuclides the environmental measurements were fewer and the uncertainties are greater.

  9. Regional emission and loss budgets of atmospheric methane (2002-2012)

    NASA Astrophysics Data System (ADS)

    Saeki, T.; Patra, P. K.; Dlugokencky, E. J.; Ishijima, K.; Umezawa, T.; Ito, A.; Aoki, S.; Morimoto, S.; Kort, E. A.; Crotwell, A. M.; Ravi Kumar, K.; Nakazawa, T.

    2015-12-01

    Methane (CH4) plays important roles in atmospheric chemistry and short-term forcing of climate. Clear understanding of atmospheric CH4's budget of emissions and losses is required to aid sustainable development of Earth's future environment. We used an atmospheric chemistry-transport model (JAMSTEC's ACTM) for simulating atmospheric CH4. An inverse modeling system has been developed for estimating CH4 emissions (7 ensemble cases) from 53 land regions for 2002-2012 using measurements at 39 sites. Global net CH4 emissions varied between 505-509 and 524-545 Tg/yr during 2002-2004 and 2010-2012, respectively (ranges based on 6 inversion cases), with a step like increase in 2007 in agreement with atmospheric measurement. The inversion system did not account for interannual variations in radicals reacting with CH4 in atmosphere. Our results suggest that the recent update of EDGAR inventory (version 4.2FT2010) overestimated global total emissions by at least 25 Tg/yr in 2010. Increase in CH4 emission since 2004 originated in the tropical and southern hemisphere regions, with timing consistent with an increase of non-dairy cattle stocks by ~10% in 2012 from 1056 million heads in 2002, leading to ~10 Tg/yr increase in emissions from enteric fermentation. All 7 inversions robustly estimated the interannual variations in emissions, but poorly constrained the seasonal cycle amplitude or phase consistently for all regions due to sparse observational network. Forward simulation results using both the a priori and a posteriori emissions are compared with independent aircraft measurements for validation. By doing that we are able to reject the upper limit (545 Tg/yr) of global total emissions as 14 Tg/yr too high during 2008-2012, which allows us to further conclude that CH4 emission increase rate over the East Asia (China mainly) region was 7-8 Tg/yr between the 2002-2006 and 2008-2012 periods, contrary to 1-17 Tg/yr in the a priori emissions.

  10. Isoprene leaf emission under CO2 free atmosphere: why and how?

    NASA Astrophysics Data System (ADS)

    Garcia, S.

    2015-12-01

    Isoprene (C5H8) is a reactive hydrocarbon gas emitted at high rates by tropical vegetation, which affects atmospheric chemistry and climate and, in the leaf level, is a very important agent against environmental stress. Under optimal conditions for photosynthesis, the majority of carbon used for isoprene biosynthesis is a direct product from recently assimilated atmospheric CO2. However, the contribution of 'alternate' carbon sources, that increase with leaf temperature, have been demonstrated and emissions of isoprene from 'alternate' carbon sources under ambient CO2 below the compensation point for photosynthesis have been observed. In this study, we investigated the response of leaf isoprene emissions under 450 ppm CO2 and CO2 free atmosphere as a function of light and leaf temperature. At constant leaf temperature (30 °C) and CO2 free atmospheres, leaves of the tropical species Inga edulis showed net emissions of CO2 and light-dependent isoprene emissions which stagnated at low light levels (75 µmol m-2 s-1 PAR) and account for 25% of that observed with 450 ppm CO2. Under constant light (1000 µmol m-2 s-1 PAR) and CO2 free atmospheres, a increase of leaf temperatures from 25 to 40 °C resulted in net emissions of CO2 and temperature-dependent isoprene emissions which reached values up to 17% of those under 450 ppm CO2. Our observations suggest that, under environmental stress, as high light/temperature and drought (when the stomata close and the amount of internal CO2 decreases), the 'alternate' carbon can maintain photosynthesis rates resulting in the production of isoprene, independent of atmospheric CO2, through the re-assimilation of internal released CO2 as an 'alternate' carbon sources for isoprene.

  11. Atmospheric CO2 capture by algae: Negative carbon dioxide emission path.

    PubMed

    Moreira, Diana; Pires, José C M

    2016-09-01

    Carbon dioxide is one of the most important greenhouse gas, which concentration increase in the atmosphere is associated to climate change and global warming. Besides CO2 capture in large emission point sources, the capture of this pollutant from atmosphere may be required due to significant contribution of diffuse sources. The technologies that remove CO2 from atmosphere (creating a negative balance of CO2) are called negative emission technologies. Bioenergy with Carbon Capture and Storage may play an important role for CO2 mitigation. It represents the combination of bioenergy production and carbon capture and storage, keeping carbon dioxide in geological reservoirs. Algae have a high potential as the source of biomass, as they present high photosynthetic efficiencies and high biomass yields. Their biomass has a wide range of applications, which can improve the economic viability of the process. Thus, this paper aims to assess the atmospheric CO2 capture by algal cultures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Ancient micrometeorites suggestive of an oxygen-rich Archaean upper atmosphere

    NASA Astrophysics Data System (ADS)

    Tomkins, Andrew G.; Bowlt, Lara; Genge, Matthew; Wilson, Siobhan A.; Brand, Helen E. A.; Wykes, Jeremy L.

    2016-05-01

    It is widely accepted that Earth’s early atmosphere contained less than 0.001 per cent of the present-day atmospheric oxygen (O2) level, until the Great Oxidation Event resulted in a major rise in O2 concentration about 2.4 billion years ago. There are multiple lines of evidence for low O2 concentrations on early Earth, but all previous observations relate to the composition of the lower atmosphere in the Archaean era; to date no method has been developed to sample the Archaean upper atmosphere. We have extracted fossil micrometeorites from limestone sedimentary rock that had accumulated slowly 2.7 billion years ago before being preserved in Australia’s Pilbara region. We propose that these micrometeorites formed when sand-sized particles entered Earth’s atmosphere and melted at altitudes of about 75 to 90 kilometres (given an atmospheric density similar to that of today). Here we show that the FeNi metal in the resulting cosmic spherules was oxidized while molten, and quench-crystallized to form spheres of interlocking dendritic crystals primarily of magnetite (Fe3O4), with wüstite (FeO)+metal preserved in a few particles. Our model of atmospheric micrometeorite oxidation suggests that Archaean upper-atmosphere oxygen concentrations may have been close to those of the present-day Earth, and that the ratio of oxygen to carbon monoxide was sufficiently high to prevent noticeable inhibition of oxidation by carbon monoxide. The anomalous sulfur isotope (Δ33S) signature of pyrite (FeS2) in seafloor sediments from this period, which requires an anoxic surface environment, implies that there may have been minimal mixing between the upper and lower atmosphere during the Archaean.

  13. Ancient micrometeorites suggestive of an oxygen-rich Archaean upper atmosphere.

    PubMed

    Tomkins, Andrew G; Bowlt, Lara; Genge, Matthew; Wilson, Siobhan A; Brand, Helen E A; Wykes, Jeremy L

    2016-05-12

    It is widely accepted that Earth's early atmosphere contained less than 0.001 per cent of the present-day atmospheric oxygen (O2) level, until the Great Oxidation Event resulted in a major rise in O2 concentration about 2.4 billion years ago. There are multiple lines of evidence for low O2 concentrations on early Earth, but all previous observations relate to the composition of the lower atmosphere in the Archaean era; to date no method has been developed to sample the Archaean upper atmosphere. We have extracted fossil micrometeorites from limestone sedimentary rock that had accumulated slowly 2.7 billion years ago before being preserved in Australia's Pilbara region. We propose that these micrometeorites formed when sand-sized particles entered Earth's atmosphere and melted at altitudes of about 75 to 90 kilometres (given an atmospheric density similar to that of today). Here we show that the FeNi metal in the resulting cosmic spherules was oxidized while molten, and quench-crystallized to form spheres of interlocking dendritic crystals primarily of magnetite (Fe3O4), with wüstite (FeO)+metal preserved in a few particles. Our model of atmospheric micrometeorite oxidation suggests that Archaean upper-atmosphere oxygen concentrations may have been close to those of the present-day Earth, and that the ratio of oxygen to carbon monoxide was sufficiently high to prevent noticeable inhibition of oxidation by carbon monoxide. The anomalous sulfur isotope (Δ(33)S) signature of pyrite (FeS2) in seafloor sediments from this period, which requires an anoxic surface environment, implies that there may have been minimal mixing between the upper and lower atmosphere during the Archaean.

  14. How important are atmospheric depressions and nocturnal low-level jets for North African dust emission?

    NASA Astrophysics Data System (ADS)

    Fiedler, Stephanie; Schepanski, Kerstin; Knippertz, Peter; Heinold, Bernd; Tegen, Ina

    2014-05-01

    Nocturnal low-level jets (NLLJs) and atmospheric depressions are known to generate wind speeds sufficient for dust emission in North Africa, but their relative importance is not well quantified. This work presents the first climatology of dust emission associated with theses phenomenon based on ERA-Interim data from the European Centre for Medium-Range Weather Forecasts. Depressions are detected as minima in the geopotential height at 925 hPa with a tracking algorithm. NLLJs are identified with a new automated detection algorithm. The results of the identification are connected with dust emissions from a dust model driven by 10m-winds from ERA-Interim. The findings highlight that atmospheric depressions are associated with 55 % of the dust emission in the annual and spatial mean. Regions south of the Atlas Mountains in spring and wide areas of North Africa during summer have contributions of up to 90 %. Lee cyclogenesis causes favourable conditions predominantly in spring while the heat low over West Africa dominates the climatology in summer. Migrating cyclones that live for more than two days are rare and associated with 4 % of the dust emission annually and spatially averaged. Maximum contributions of cyclones to dust emission are 25 % over eastern North Africa in spring. This result suggests that few depressions forming near the Atlas Mountains undergo the development to a long-lived and moving cyclone. Even though their total contribution to dust emission is small, the emission intensity is large. The climatological mean of the emission flux is exceeded by a factor of four to eight during cyclones. The presence of soil moisture during cyclones suppresses 10 % of the dust emission. The daytime fluxes are three to five times larger than at night. NLLJs are wind speed maxima at night that build at a few 100 m above the surface. Annually and spatially averaged, NLLJs form in 29 % of nights. Single regions and seasons, e.g. the Bodélé Depression in winter and the

  15. An interpretation of the spectral properties of hot hydrogen-rich white dwarfs with stratified H/He model atmospheres

    NASA Technical Reports Server (NTRS)

    Vennes, Stephane; Fontaine, Gilles

    1992-01-01

    A grid of stratified H/He model atmospheres applicable to the interpretation of the spectral properties of hot H-rich white dwarfs (WDs) is computed. Samples of hot DA WDs observed with Exosat and Einstein are analyzed using the models. Six out of six objects with T(eff) = 35,000 K or less do not show a EUV/soft X-ray flux deficiency and therefore can be understood solely in terms of pure hydrogen atmospheres. A majority of DA WDs hotter than this value do show a flux deficiency and thus require the presence of some absorbers in their atmospheres. It is shown that the Exosat broadband photometry of Feige 24 and G191 B2B cannot be explained in terms of stratified atmospheres. Absorption by heavy elements is certainly responsible for the required EUV/soft X-ray opacity source in these cases. However, the Exosat data are consistent with the hypothesis of stratified atmospheres in the four remaining objects.

  16. [Inventories of atmospheric arsenic emissions from coal combustion in China, 2005].

    PubMed

    Tian, He-Zhong; Qu, Yi-Ping

    2009-04-15

    Anthropogenic arsenic (As) emitted from coal combustion is one of key trace elements leading to negative air pollution and national economy loss. It is of great significance to estimate the atmospheric arsenic emission for proposing relevant laws or regulations and selecting proper pollution control technologies. The inventories of atmospheric arsenic emissions from coal combustion in China were evaluated by adopting the emission factor method based on fuel consumption. Arsenic emission sources were firstly classified into several categories by economic sectors, combustion types and pollution control technologies. Then, according to provincial coal consumption and averaged arsenic concentration in the feed fuel, the inventories of atmospheric arsenic emission from coal combustion in China in 2005 were established. Coal outputand consumption in China in 2005 were 2,119.8 and 2,099.8 Mt, respectively. The total emissions of arsenic released into the atmosphere in 2005 in China were estimated at about 1,564.4 t, and Shandong ranked the largest province with 144.4 t arsenic release, followed by Hunan (141.1 t), Hebei (108.5 t), Henan (77.7 t), and Jiangsu (77.0 t), which were mainly concentrated in the eastern and central provinces of China. The arsenic emissions were largely emitted by industry sector (818.8 t) and thermal power generation sector (303.4 t), contributing 52.3% and 19.4% of the totals, respectively. About 375.5 t arsenic was estimated to be released into the atmosphere in the form of gas phase in China in 2005, with a share of 24% of the totals. In general, arsenic pollution control from coal combustion should be highlighted for the power and industry sectors in the whole country. However, arsenic poisoning caused by residential coal burning should also be paid great attention in some areas such as Xinjiang, Gansu, Qinghai and Guishou.

  17. Mercury and plants in contaminated soils. 1: Uptake, partitioning, and emission to the atmosphere

    SciTech Connect

    Leonard, T.L.; Gustin, M.S.; Fernandez, G.C.J.; Taylor, G.E. Jr.

    1998-10-01

    The uptake, distribution, and subsequent emission of mercury to the atmosphere were investigated in five plant species (Lepidium latifolium [L.], Artemisia douglasiana [Bess in Hook], Caulanthus sp. [S. Watson], Fragaria vesca [L.], and Eucalyptus globulus [Labill]) with different ecological and physiological attributes. Transfer coefficients for mercury in the soil-plant system were calculated. Plant-to-atmosphere emissions of mercury were determined using a controlled environment gas-exchange system and ranged from 10 to 93 mg/m{sup 2}/h in the light; emissions in the dark were an order of magnitude less. Transfer coefficients for mercury within the soil-plant system increased acropetally (root-to-leaf axis) by orders of magnitude. Estimated mercury emissions from plants in the Carson River Drainage Basin of Nevada over the growing season (0.5 mg/m{sup 2}) add to the previously reported soil mercury emissions (8.5 mg/m{sup 2}), resulting in total landscape emissions of 9 mg/m{sup 2}. For L. latifolium, 70% of the mercury taken up by the roots during the growing season was emitted to the atmosphere. For every one molecule of mercury retained in foliage of L. latifolium, 12 molecules of mercury were emitted. Within this arid ecosystem, mercury emissions are a dominant pathway of the mercury cycle. Plants function as conduits for the interfacial transport of mercury from the geosphere to the atmosphere, and this role is undervalued in models of the behavior of mercury in terrestrial exosystems and in the atmosphere on a global scale.

  18. Measurements of atmospheric hydrocarbons and biogenic emission fluxes in the Amazon boundary layer

    NASA Technical Reports Server (NTRS)

    Zimmerman, P. R.; Greenberg, J. P.; Westberg, C. E.

    1988-01-01

    Tropospheric mixing ratios of methane, C2-C10 hydrocarbons, and carbon monoxide were measured over the Amazon tropical forest near Manaus, Amazonas, Brazil, in July and August 1985. The measurements, consisting mostly of altitude profiles of these gases, were all made within the atmospheric boundary layer up to an altitude of 1000 m above ground level. Data characterize the diurnal hydrocarbon composition of the boundary layer. Biogenic emissions of isoprene control hydroxyl radical concentrations over the forest. Biogenic emission fluxes of isoprene and terpenes are estimated to be 25,000 micrograms/sq m per day and 5600 micrograms/sq m per day, respectively. This isoprene emission is equivalent to 2 percent of the net primary productivity of the tropical forest. Atmospheric oxidation of biogenic isoprene and terpenes emissions from the Amazon forest may account for daily increases of 8-13 ppb for carbon monoxide in the planetary boundary layer.

  19. Measurements of atmospheric hydrocarbons and biogenic emission fluxes in the Amazon boundary layer

    NASA Technical Reports Server (NTRS)

    Zimmerman, P. R.; Greenberg, J. P.; Westberg, C. E.

    1988-01-01

    Tropospheric mixing ratios of methane, C2-C10 hydrocarbons, and carbon monoxide were measured over the Amazon tropical forest near Manaus, Amazonas, Brazil, in July and August 1985. The measurements, consisting mostly of altitude profiles of these gases, were all made within the atmospheric boundary layer up to an altitude of 1000 m above ground level. Data characterize the diurnal hydrocarbon composition of the boundary layer. Biogenic emissions of isoprene control hydroxyl radical concentrations over the forest. Biogenic emission fluxes of isoprene and terpenes are estimated to be 25,000 micrograms/sq m per day and 5600 micrograms/sq m per day, respectively. This isoprene emission is equivalent to 2 percent of the net primary productivity of the tropical forest. Atmospheric oxidation of biogenic isoprene and terpenes emissions from the Amazon forest may account for daily increases of 8-13 ppb for carbon monoxide in the planetary boundary layer.

  20. The EFFIS forest fire atmospheric emission model: Application to a major fire event in Portugal

    NASA Astrophysics Data System (ADS)

    Monteiro, A.; Corti, P.; San Miguel-Ayanz, J.; Miranda, A. I.; Borrego, C.

    2014-02-01

    Forest fires are a major contributor of gaseous and particulate compounds to the atmosphere, impairing air quality and affecting human health. A new forest fire emissions module was developed and integrated into the European Forest Fire Information System (EFFIS), which systematically compiles, since 2000, series of burnt area statistics mapped from satellite imagery. This new forest fire emission model was built on classical methodologies of fuel-map based emission estimation that were improved, especially on burning efficiency, fuel consumption estimation and emission factors. It makes the best use of EFFIS near-real time and detailed information on forest fires, mainly concerning products with a high temporal resolution, which is needed to simulate smoke dispersion and chemical transformation in the atmosphere.

  1. The constitution of the atmospheric layers and the extreme ultraviolet spectrum of hot hydrogen-rich white dwarfs

    NASA Technical Reports Server (NTRS)

    Vennes, Stephane

    1992-01-01

    An analysis is presented of the atmospheric properties of hot, H-rich, DA white dwarfs that is based on optical, UV, and X-ray observations aimed at predicting detailed spectral properties of these stars in the range 80-800 A. The divergences between observations from a sample of 15 hot DA white dwarfs emitting in the EUV/soft X-ray range and pure H synthetic spectra calculated from a grid of model atmospheres characterized by Teff and g are examined. Seven out of 15 DA stars are found to consistently exhibit pure hydrogen atmospheres, the remaining seven stars showing inconsistency between FUV and EUV/soft X-ray data that can be explained by the presence of trace EUV/soft X-ray absorbers. Synthetic data are computed assuming two other possible chemical structures: photospheric traces of radiatively levitated heavy elements and a stratified hydrogen/helium distribution. Predictions about forthcoming medium-resolution observations of the EUV spectrum of selected hot H-rich white dwarfs are made.

  2. The constitution of the atmospheric layers and the extreme ultraviolet spectrum of hot hydrogen-rich white dwarfs

    NASA Technical Reports Server (NTRS)

    Vennes, Stephane

    1992-01-01

    An analysis is presented of the atmospheric properties of hot, H-rich, DA white dwarfs that is based on optical, UV, and X-ray observations aimed at predicting detailed spectral properties of these stars in the range 80-800 A. The divergences between observations from a sample of 15 hot DA white dwarfs emitting in the EUV/soft X-ray range and pure H synthetic spectra calculated from a grid of model atmospheres characterized by Teff and g are examined. Seven out of 15 DA stars are found to consistently exhibit pure hydrogen atmospheres, the remaining seven stars showing inconsistency between FUV and EUV/soft X-ray data that can be explained by the presence of trace EUV/soft X-ray absorbers. Synthetic data are computed assuming two other possible chemical structures: photospheric traces of radiatively levitated heavy elements and a stratified hydrogen/helium distribution. Predictions about forthcoming medium-resolution observations of the EUV spectrum of selected hot H-rich white dwarfs are made.

  3. HST Observations of Titan's Escaping Atmosphere in Transit and in Emission

    NASA Astrophysics Data System (ADS)

    Clarke, John

    2007-07-01

    We propose UV observations using the ACS/SBC of Titan's extended escaping atmosphere for the Jan/Feb 2009 period of transits of Titan across Saturn. A combination of absorption of Saturn's reflected solar UV emission in transit, and extended emissions primarily from H atoms away from transit, will yield new information about the structur of Titan's extended upper atmosphere. These observations are expected to provide new constraints on theoretical models for a hydrodynamic flow of species through Titan's exobase level, resulting from the interpreation of recent Cassini measurements at Titan.

  4. Characteristic emission enhancement in the atmosphere with Rn trace using metal assisted LIBS

    SciTech Connect

    Hashemi, M. M.; Parvin, P. Moosakhani, A.; Mortazavi, S. Z.; Reyhani, A.; Majdabadi, A.; Abachi, S.

    2014-06-15

    Several characteristic emission lines from the metal targets (Cu, Zn and Pb) were investigated in trace presence of radon gas in the atmospheric air, using Q-SW Nd:YAG laser induced plasma inside a control chamber. The emission lines of metal species are noticeably enhanced in (Rn+air), relative to those in the synthetic air alone. Similar spectra were also taken in various sub-atmospheric environments in order to determine the optimum pressure for enhancement. Solid-state nuclear track detectors were also employed to count the tracks due to alpha particles for the activity assessment.

  5. XUV-Exposed, Non-Hydrostatic Hydrogen-Rich Upper Atmospheres of Terrestrial Planets. Part I: Atmospheric Expansion and Thermal Escape

    PubMed Central

    Lammer, Helmut; Odert, Petra; Kulikov, Yuri N.; Kislyakova, Kristina G.; Khodachenko, Maxim L.; Güdel, Manuel; Hanslmeier, Arnold; Biernat, Helfried

    2013-01-01

    Abstract The recently discovered low-density “super-Earths” Kepler-11b, Kepler-11f, Kepler-11d, Kepler-11e, and planets such as GJ 1214b represent the most likely known planets that are surrounded by dense H/He envelopes or contain deep H2O oceans also surrounded by dense hydrogen envelopes. Although these super-Earths are orbiting relatively close to their host stars, they have not lost their captured nebula-based hydrogen-rich or degassed volatile-rich steam protoatmospheres. Thus, it is interesting to estimate the maximum possible amount of atmospheric hydrogen loss from a terrestrial planet orbiting within the habitable zone of late main sequence host stars. For studying the thermosphere structure and escape, we apply a 1-D hydrodynamic upper atmosphere model that solves the equations of mass, momentum, and energy conservation for a planet with the mass and size of Earth and for a super-Earth with a size of 2 REarth and a mass of 10 MEarth. We calculate volume heating rates by the stellar soft X-ray and extreme ultraviolet radiation (XUV) and expansion of the upper atmosphere, its temperature, density, and velocity structure and related thermal escape rates during the planet's lifetime. Moreover, we investigate under which conditions both planets enter the blow-off escape regime and may therefore experience loss rates that are close to the energy-limited escape. Finally, we discuss the results in the context of atmospheric evolution and implications for habitability of terrestrial planets in general. Key Words: Stellar activity—Low-mass stars—Early atmospheres—Earth-like exoplanets—Energetic neutral atoms—Ion escape—Habitability. Astrobiology 13, 1011–1029. PMID:24251443

  6. XUV-exposed, non-hydrostatic hydrogen-rich upper atmospheres of terrestrial planets. Part I: atmospheric expansion and thermal escape.

    PubMed

    Erkaev, Nikolai V; Lammer, Helmut; Odert, Petra; Kulikov, Yuri N; Kislyakova, Kristina G; Khodachenko, Maxim L; Güdel, Manuel; Hanslmeier, Arnold; Biernat, Helfried

    2013-11-01

    The recently discovered low-density "super-Earths" Kepler-11b, Kepler-11f, Kepler-11d, Kepler-11e, and planets such as GJ 1214b represent the most likely known planets that are surrounded by dense H/He envelopes or contain deep H₂O oceans also surrounded by dense hydrogen envelopes. Although these super-Earths are orbiting relatively close to their host stars, they have not lost their captured nebula-based hydrogen-rich or degassed volatile-rich steam protoatmospheres. Thus, it is interesting to estimate the maximum possible amount of atmospheric hydrogen loss from a terrestrial planet orbiting within the habitable zone of late main sequence host stars. For studying the thermosphere structure and escape, we apply a 1-D hydrodynamic upper atmosphere model that solves the equations of mass, momentum, and energy conservation for a planet with the mass and size of Earth and for a super-Earth with a size of 2 R(Earth) and a mass of 10 M(Earth). We calculate volume heating rates by the stellar soft X-ray and extreme ultraviolet radiation (XUV) and expansion of the upper atmosphere, its temperature, density, and velocity structure and related thermal escape rates during the planet's lifetime. Moreover, we investigate under which conditions both planets enter the blow-off escape regime and may therefore experience loss rates that are close to the energy-limited escape. Finally, we discuss the results in the context of atmospheric evolution and implications for habitability of terrestrial planets in general.

  7. Experimental Degassing of Volatile Bearing Martian Magmas into a CO2-rich Atmosphere: Magmatic Vapor-Driven Surface Modification and Contribution to the Atmosphere

    NASA Astrophysics Data System (ADS)

    Ustunisik, G. K.; Nekvasil, H.; Lindsley, D. H.

    2011-12-01

    A variety of studies have focused on redistribution of mantle material by ascent of magmas through the crust, and the nature of these magmas and their compositional evolution (Nekvasil et al. 2009; McCubbin et al. 2009; McCubbin et al. 2010). An additional strong focus has been surface alteration/weathering and redistribution of surface materials by sedimentary processes. In order to fully understand Mars as a system, however, we also need to determine the results of interaction of magmatic vapors with surface materials, such as alteration and volatile sequestration, and, through this, assess the net contribution to the martian atmosphere. It has been suggested that the early martian atmosphere was CO2-rich(Michalski and Niles 2010; Morris et al. 2010; Harvey 2010), but that it eventually lost this characteristic over time. It is possible that the nature of the magmatic vapor interaction with surface materials and the magmatic volatile contribution to the Martian atmosphere changed over time in response to this. To investigate this possibility we have initiated a set of experiment that assess relative loss of magma-hosted S, F, Cl and water to a CO2-rich and a CO2-poor atmosphere, the nature of sublimates produced with dropping temperature, and the type of alteration assemblages that could lead to volatile sequestration. The experiments were designed to simulate degassing of a volatile-rich martian magma that ascended rapidly and retained much of its volatile load until eruption onto the surface at a pressure of between 0.3 and 1 bar. Sealed silica tubes were used which hosted the synthetic volatile-containing martian basalt, the oxygen buffer assemblage and CO2 source, and a capsule containing crushed wallrock for reaction with the vapor phase in a well-characterized thermal gradient. These tubes were suspended in a vertical Pt-wound furnace and heated for several hours at a temperature just above the liquidus to simulate first boiling. Preliminary results will be

  8. Effectiveness of Emission Controls to Reduce the Atmospheric Concentrations of Mercury.

    PubMed

    Castro, Mark S; Sherwell, John

    2015-12-15

    Coal-fired power plants in the United States are required to reduce their emissions of mercury (Hg) into the atmosphere to lower the exposure of Hg to humans. The effectiveness of power-plant emission controls on the atmospheric concentrations of Hg in the United States is largely unknown because there are few long-term high-quality atmospheric Hg data sets. Here, we present the atmospheric concentrations of Hg and sulfur dioxide (SO2) measured from 2006 to 2015 at a relatively pristine location in western Maryland that is several (>50 km) kilometers downwind of power plants in Ohio, Pennsylvania, and West Virginia. Annual average atmospheric concentrations of gaseous oxidized mercury (GOM), SO2, fine particulate mercury (PBM2.5), and gaseous elemental mercury (GEM) declined by 75%, 75%, 43%, and 13%, respectively, and were strongly correlated with power-plant Hg emissions from the upwind states. These results provide compelling evidence that reductions in Hg emissions from power plants in the United States had their intended impact to reduce regional Hg pollution.

  9. Atmospheric constraints on the methane emissions from the East Siberian Shelf

    NASA Astrophysics Data System (ADS)

    Berchet, Antoine; Bousquet, Philippe; Pison, Isabelle; Locatelli, Robin; Chevallier, Frédéric; Paris, Jean-Daniel; Dlugokencky, Ed J.; Laurila, Tuomas; Hatakka, Juha; Viisanen, Yrjo; Worthy, Doug E. J.; Nisbet, Euan; Fisher, Rebecca; France, James; Lowry, David; Ivakhov, Viktor; Hermansen, Ove

    2016-03-01

    Subsea permafrost and hydrates in the East Siberian Arctic Shelf (ESAS) constitute a substantial carbon pool, and a potentially large source of methane to the atmosphere. Previous studies based on interpolated oceanographic campaigns estimated atmospheric emissions from this area at 8-17 TgCH4 yr-1. Here, we propose insights based on atmospheric observations to evaluate these estimates. The comparison of high-resolution simulations of atmospheric methane mole fractions to continuous methane observations during the whole year 2012 confirms the high variability and heterogeneity of the methane releases from ESAS. A reference scenario with ESAS emissions of 8 TgCH4 yr-1, in the lower part of previously estimated emissions, is found to largely overestimate atmospheric observations in winter, likely related to overestimated methane leakage through sea ice. In contrast, in summer, simulations are more consistent with observations. Based on a comprehensive statistical analysis of the observations and of the simulations, annual methane emissions from ESAS are estimated to range from 0.0 to 4.5 TgCH4 yr-1. Isotopic observations suggest a biogenic origin (either terrestrial or marine) of the methane in air masses originating from ESAS during late summer 2008 and 2009.

  10. Emission lines in the atmosphere of the irradiated brown dwarf WD0137-349B

    NASA Astrophysics Data System (ADS)

    Longstaff, E. S.; Casewell, S. L.; Wynn, G. A.; Maxted, P. F. L.; Helling, Ch.

    2017-10-01

    We present new optical and near-infrared spectra of WD0137-349; a close white dwarf-brown dwarf non-interacting binary system with a period of ≈114 min. We have confirmed the presence of H α emission and discovered He, Na, Mg, Si, K, Ca, Ti and Fe emission lines originating from the brown-dwarf atmosphere. This is the first brown-dwarf atmosphere to have been observed to exhibit metal emission lines as a direct result of intense irradiation. The equivalent widths of many of these lines show a significant difference between the day-side and night-side of the brown dwarf. This is likely an indication that efficient heat redistribution may not be happening on this object, in agreement with models of hot Jupiter atmospheres. The H α line strength variation shows a strong phase dependency as does the width. We have simulated the Ca II emission lines using a model that includes the brown-dwarf Roche geometry and limb darkening, and we estimate the mass ratio of the system to be 0.135 ± 0.004. We also apply a gas-phase equilibrium code using a prescribed drift-phoenix model to examine how the chemical composition of the brown-dwarf upper atmosphere would change given an outward temperature increase, and discuss the possibility that this would induce a chromosphere above the brown-dwarf atmosphere.

  11. Probing Atmospheric Electric Fields in Thunderstorms through Radio Emission from Cosmic-Ray-Induced Air Showers.

    PubMed

    Schellart, P; Trinh, T N G; Buitink, S; Corstanje, A; Enriquez, J E; Falcke, H; Hörandel, J R; Nelles, A; Rachen, J P; Rossetto, L; Scholten, O; Ter Veen, S; Thoudam, S; Ebert, U; Koehn, C; Rutjes, C; Alexov, A; Anderson, J M; Avruch, I M; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Broderick, J W; Brüggen, M; Butcher, H R; Ciardi, B; de Geus, E; de Vos, M; Duscha, S; Eislöffel, J; Fallows, R A; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Heald, G; Hessels, J W T; Hoeft, M; Holties, H A; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; Mann, G; McFadden, R; McKay-Bukowski, D; McKean, J P; Mevius, M; Moldon, J; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Scaife, A M M; Schwarz, D J; Serylak, M; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Tasse, C; Toribio, M C; van Weeren, R J; Vermeulen, R; Vocks, C; Wise, M W; Wucknitz, O; Zarka, P

    2015-04-24

    We present measurements of radio emission from cosmic ray air showers that took place during thunderstorms. The intensity and polarization patterns of these air showers are radically different from those measured during fair-weather conditions. With the use of a simple two-layer model for the atmospheric electric field, these patterns can be well reproduced by state-of-the-art simulation codes. This in turn provides a novel way to study atmospheric electric fields.

  12. Constraining hot Jupiter’s atmospheric structure and dynamics through Doppler shifted emission spectra

    NASA Astrophysics Data System (ADS)

    Zhang, Jisheng; Kempton, Eliza; Rauscher, Emily

    2017-01-01

    In recent years, astronomers have begun successfully observing the atmospheres of extrasolar planets using ground-based telescopes equipped with spectrographs capable of observing at high spectral resolution (R~105). Such studies are capable of diagnosing the atmospheric structure, composition, and dynamics (winds and rotation) of both transiting and non-transiting exoplanets. However, few studies have examined how the 3-D atmospheric dynamics could alter the emitted light of hot Jupiters at such high spectral resolution. Here, we present a model to explore such influence on the hot Jupiters’ thermal emission spectra. Our aim is to investigate the extent to which the effects of 3-D atmospheric dynamics are imprinted on planet-averaged thermal emission spectra. We couple together a 3-D general circulation model of hot Jupiter atmospheric dynamics (Rauscher & Menou, 2012) with a radiative transfer solver to predict the planet’s disk-integrated emission spectrum as a function of its orbital phase. For the first time, we self-consistently include the effects of the line-of-sight atmospheric motions (resulting from winds and rotation) in the calculation to produce Doppler-shifted spectral line profiles that result from the atmospheric dynamics. We focus our study on three benchmark hot Jupiters, HD 189733b, HD 209458b, and WASP-43b which have been the focus of previous detailed observational studies. We find that the high-resolution Doppler shifted thermal emission spectra can be used to diagnose key properties of the dynamical atmosphere - the planet’s longitudinal temperature and wind structure, and its rotation rate.

  13. Airborne Measurements of the Atmospheric Emissions from a Fuel Ethanol Refinery

    NASA Astrophysics Data System (ADS)

    De Gouw, J. A.; McKeen, S. A.; Aikin, K. C.; Brock, C. A.; Brown, S. S.; Gilman, J.; Graus, M.; Hanisco, T. F.; Holloway, J. S.; Lerner, B. M.; Kaiser, J.; Keutsch, F. N.; Liao, J.; Markovic, M. Z.; Middlebrook, A. M.; Min, K. E.; Neuman, J. A.; Nowak, J. B.; Peischl, J.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Trainer, M.; Veres, P. R.; Warneke, C.; Welti, A.; Wolfe, G. M., Jr.

    2014-12-01

    Ethanol made from corn now constitutes approximately 10% of the fuel used in gasoline vehicles in the United States. The ethanol is produced in over 200 fuel ethanol refineries across the country. In this work, we report measurements of the atmospheric emissions from the third largest fuel ethanol refinery in the U.S. located in Decatur, Illinois. Measurements were made from the NOAA WP-3D research aircraft during the NOAA Southeast Nexus (SENEX) campaign in the summer of 2013, which was part of the larger Southeast Atmosphere Study (SAS). Emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) agreed with reported emissions in the 2011 National Emissions Inventory (NEI-2011). In contrast, emissions of several volatile organic compounds (VOCs) including ethanol, formaldehyde and acetaldehyde, were underestimated by an order of magnitude in the NEI-2011. By combining data from the NEI-2011 and fuel ethanol production numbers from the Renewable Fuels Association, we calculate emission intensities for SO2, NOx and VOCs, defined as the emissions per volume of fuel produced. These emission intensities can be readily compared to fuel-based emission factors from gasoline vehicles and the relative contributions made by fuel refining and fuel use to overall emissions will be quantified. Emission intensities of SO2 and NOx are particularly high for those fuel ethanol refineries that use coal as an energy source, including the plant in Decatur studied in this work. Finally, by comparing the measurements at different distances downwind, chemical transformation of the emissions could be observed, including the formation of new particles, peroxyacyl nitrates, ozone and sulfate aerosol.

  14. Methane emissions in the Arctic and sub-Arctic from a Bayesian atmospheric inversion

    NASA Astrophysics Data System (ADS)

    Thompson, Rona; Stohl, Andreas; Myhre, Cathrine Lund; Sasakawa, Motoki; Machida, Toshinobu; Aalto, Tuula; Dlugokencky, Edward; Worthy, Douglas

    2015-04-01

    Methane (CH4) is the second most important anthropogenic greenhouse gas after CO2. Globally, atmospheric CH4 concentrations have increased since direct measurements began, in the early 1980s, but then stabilized from the mid 1990s to the mid 2000s. Since 2006, the atmospheric CH4 growth rate has become positive again causing concern that it may be the response to climate feedbacks, especially in the Arctic, where there is a potential for a large release of CH4 to the atmosphere under warmer conditions. Such feedbacks include high latitude wetlands, permafrost and methane hydrates. Conversely, recent studies, suggest that this change is the result of a rise in wetland emissions of CH4 in the tropics and subtropics combined with a rise in fossil fuel emissions. We present CH4 emission estimates for the Arctic and sub-Arctic from 2007 to 2011 using atmospheric mole fraction observations in a Bayesian inversion framework. This framework is based on the Lagrangian Particle Dispersion model, FLEXPART, run with ECMWF meteorological analyses. Emissions were optimized monthly and on a spatial grid of variable resolution (from 1°×1° to 4°×4°). Background mixing ratios were found by coupling FLEXPART to output from the Eulerian chemistry transport model, TM5. We found evidence of a widespread release of CH4 corresponding to the onset of soil freezing. Furthermore, we find higher emissions in Northern Eurasia compared to the prior in both summer and winter.

  15. Methyl Chavicol: Characterization of its Biogenic Emission Rate, Abundance, and Oxidation Products in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Bouvier-Brown, N. C.; Goldstein, A. H.; Worton, D. R.; Matross, D. M.; Gilman, J.; Kuster, W.; Degouw, J.; Cahill, T. M.; Holzinger, R.

    2008-12-01

    We report quantitative measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments: gas chromatograph with mass spectrometer detector (GC-MS), proton transfer reaction mass spectrometer (PTR-MS), and thermal desorption aerosol GC-MS (TAG). Previously identified as a potential bark beetle disruptant, methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO), a light and temperature dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4-68 % of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72-10.2 μ gCg-1h-1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde) in the ambient atmosphere. Methyl chavicol is a major essential oil component of many species. We propose this newly- characterized biogenic compound should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  16. 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...

  17. Updated emission inventories for speciated atmospheric mercury from anthropogenic sources in China.

    PubMed

    Zhang, Lei; Wang, Shuxiao; Wang, Long; Wu, Ye; Duan, Lei; Wu, Qingru; Wang, Fengyang; Yang, Mei; Yang, Hai; Hao, Jiming; Liu, Xiang

    2015-03-03

    China is the largest contributor to global atmospheric mercury (Hg), and accurate emission inventories in China are needed to reduce large gaps existing in global Hg mass balance estimates and assess Hg effects on various ecosystems. The China Atmospheric Mercury Emission (CAME) model was developed in this study using probabilistic emission factors generated from abundant on-site measurements and literature data. Using this model, total anthropogenic Hg emissions were estimated to be continuously increasing from 356 t in 2000 to 538 t in 2010 with an average annual increase rate of 4.2%. Industrial coal combustion, coal-fired power plants, nonferrous metal smelting, and cement production were identified to be the dominant Hg emission sources in China. The ten largest contributing provinces accounted for nearly 60% of the total Hg emissions in 2010. Speciated Hg emission inventory was developed over China with a grid-resolution of 36 × 36 km, providing needed emission fields for Hg transport models. In this new inventory, the sectoral Hg speciation profiles were significantly improved based on the latest data from field measurements and more detailed technology categorization. The overall uncertainties of the newly developed inventory were estimated to be in the range of -20% to +23%.

  18. Theoretical background of optical emission spectroscopy for analysis of atmospheric pressure plasmas

    NASA Astrophysics Data System (ADS)

    Belmonte, Thierry; Noël, Cédric; Gries, Thomas; Martin, Julien; Henrion, Gérard

    2015-12-01

    This review contains a theoretical background of optical emission spectroscopy and some selected examples of issues in the field of atmospheric plasmas. It includes elements like line broadening, emission of continua and molecules, radiation models, etc. Modernized expressions figuring the terms hidden in global constants where cgs units prevail are given together with restrictions of use. Easy-to-use formulas are provided to give access to essential plasma parameters.

  19. The Effects of Surface Longwave Emissivity on Atmospheric Circulation and Convection at Sahara and Sahel Regions

    NASA Astrophysics Data System (ADS)

    Chen, Y. H.; Chen, X.; Huang, X.; Flanner, M.

    2016-12-01

    The longwave spectral emissivities of desert and vegetation are considerably different from blackbody emissivity. A dominant majority of current atmospheric GCMs still treat the surface as blackbody and ignore spectral variations of surface emissivity. Charney (1975) proposed a positive feedback in arid areas via interactions among solar radiation, surface albedo, and atmospheric motion. This leads us to postulate that similar feedback as in Charney (1975) could operate in the longwave and such longwave feedback might not be properly represented by current GCMs. We incorporate realistic surface spectral emissivity over the Sahara and Sahel regions, where the emissivity is as low as 0-6-0.7 over the IR window region, into the NCAR CESM v1.1.1, while keeping treatments for the rest of the globe unchanged. Both the standard and the modified CESM are then used to carry out a 10-year simulation with prescribed climatological SST. Compared to the standard CESM simulation, the mean surface radiative temperature in the modified CESM simulation increases by 1.6 K over the region. However, the net upward longwave flux at the top of the atmosphere is decreased by 2.33 Wm-2 because the low emissivity of desert leads to less longwave emission over the IR window region. Energy budget analysis shows that the atmospheric radiative cooling over the region is decreased by 1.33 Wm-2 in the modified CESM simulation. The changes in 500-hPa vertical velocities indicate in average enhanced descending motion over the region, result in suppression of convection, which in return enhances arid situation in the region. Our findings demonstrate that change in surface LW spectral emissivity can influence simulated climate in the Sahara and Sahel regions in a way, to some extent, similar to the mechanism proposed by Charney (1975).

  20. Origin of Life in Fe-poor Oceans Under a CH4-rich and SO2-poor Atmosphere: I. Theoretical Approach

    NASA Astrophysics Data System (ADS)

    Ohmoto, H.; Salvan, C. M.

    2010-04-01

    Thermochemical calculations of gas/fluid speciation in submarine hydrothermal fluids and volcanic gas suggest the pre-biotic atmosphere was methane rich and strongly reducing. This supports the Urey-Miller model for the origin of life.

  1. Space shuttle observation of an unusual transient atmospheric emission

    NASA Astrophysics Data System (ADS)

    Yair, Yoav; Price, Colin; Ziv, Baruch; Israelevich, Peter L.; Sentman, Davis D.; São-Sabbas, Fernanda T.; Devir, Adam D.; Sato, Mitsuteru; Rodger, Craig J.; Moalem, Meir; Greenberg, Eran; Yaron, Ofer

    2005-01-01

    We report an observation of an unusual transient luminous event (TLE) detected in the near IR, south of Madagascar above the Indian Ocean. The event was imaged from the space shuttle Columbia during the MEIDEX sprite campaign [Yair et al., 2004]. It was delayed 0.23 seconds from a preceding visual lightning flash which was horizontally displaced >1000 km from the event. The calculated brightness in the 860 (+/-50) nm filter was ~310 +/- 30 kR, and the morphology of the emitting volume did not resemble any known class of TLE (i.e., sprites, ELVES or halos). This TIGER event (Transient Ionospheric Glow Emission in Red) may constitute a new class of TLE, not necessarily induced by a near-by thunderstorm. We discuss possible generation mechanisms, including the conjugate sprite hypothesis caused by lightning at the magnetic mirror point, lightning-induced electron precipitation and an extraterrestrial source, meteoric or cometary.

  2. Assessing Greenhouse Gas emissions in the Greater Toronto Area using atmospheric observations (Invited)

    NASA Astrophysics Data System (ADS)

    Vogel, F. R.; Chan, E.; Huang, L.; Levin, I.; Worthy, D.

    2013-12-01

    Urban areas are said to be responsible for approximately 75% of anthropogenic Greenhouse Gases (GHGs) emissions while comprising only two percent of the land area [1]. This limited spatial expansion should facilitate a monitoring of anthropogenic GHGs from atmospheric observations. As major sources of emissions, cities also have a huge potential to drive emissions reductions. To effectively manage emissions, cities must however, first measure and report these publicly [2]. Modelling studies and measurements of CO2 from fossil fuel burning (FFCO2) in densely populated areas does, however, pose several challenges: Besides continuous in-situ observations, i.e. finding an adequate atmospheric transport model, a sufficiently fine-grained FFCO2 emission model and the proper background reference observations to distinguish the large-scale from the local/urban contributions to the observed FFCO2 concentration offsets ( ΔFFCO2) are required. Pilot studies which include the data from two 'sister sites*' in the vicinity of Toronto, Canada helped to derive flux estimates for Non-CO2 GHGs [3] and improve our understanding of urban FFCO2 emissions. Our 13CO2 observations reveal that the contribution of natural gas burning (mostly due to domestic heating) account for 80%×7% of FFCO2 emissions in the Greater Toronto Area (GTA) during winter. Our 14CO2 observations in the GTA, furthermore, show that the local offset of CO2 (ΔCO2) between our two sister sites can be largely attributed to urban FFCO2 emissions. The seasonal cycle of the observed ΔFFCO2 in Toronto, combined with high-resolution atmospheric modeling, helps to independently assess the contribution from different emission sectors (transportation, primary energy and industry, domestic heating) as predicted by a dedicated city-scale emission inventory, which deviates from a UNFCCC-based inventory. [1] D. Dodman. 2009. Blaming cities for climate change? An analysis of urban greenhouse gas emissions inventories

  3. Quantification of atmospheric lead emissions from 70 years of leaded petrol consumption in Australia

    NASA Astrophysics Data System (ADS)

    Kristensen, Louise Jane

    2015-06-01

    Lead is a persistent pollutant and the subject of many environmental studies, yet, in Australia, the extent of atmospheric lead emissions from the use of leaded petrol is unquantified. This paper details the first comprehensive account of leaded petrol sales and its lead concentrations over the 70 years of use in Australia. The resulting atmospheric lead emissions are calculated to provide the most complete understanding of the volume of lead released to the Australian continent from the consumption of leaded petrol. Atmospheric emissions of lead to the entire Australian continent from leaded petrol are calculated to total 240,510 tonnes over seven decades of use, peaking at 7869 tonnes in 1974. Total emissions for individual states and territories range from 1745 to 67,893 tonnes, with New South Wales responsible for the largest emissions. The effect of regulations on allowable concentrations of tetraethyl-lead additives are observed in the reduction of lead emissions in New South Wales and Victoria. The consequences to human health and the environment of leaded petrol consumption in Australia's populous cities are examined against historical air quality data and blood lead levels.

  4. Atmospheric Absorption Applied to Plume Emission. Experimental and Analytical Investigations of Hot Gas Emission Attenuated by Cold Gases

    DTIC Science & Technology

    1975-08-01

    ABSTRACT ( Continued ) Spectral measurements of the radiance of a hot gas cell, both unattenuated and attenrated by a long simulated atmospheric path, were...Molecular Spectroscopy and Gas Emissivities, Addison -Wesley, Readirg, Massachusetts, 1959. of their magnitude. Burch et al.,[6 made limited measurements ...PERFORMING ORGANIZATIOM NAME AND ADDRESS tO. PROGRAM ELEMENT. PROJECT. TASK Enviromental Research Institute of Michigan AREA I WORK UNIT NUMUERS Infrared and

  5. One Martian Year of Atmospheric Observations by the Thermal Emission Spectrometer

    NASA Technical Reports Server (NTRS)

    Smith, Michael D.; Pearl, John C.; Conrath, Barney J.; Christensen, Philip R.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    The Mars Global Surveyor has completed one full Martian year of mapping. Infrared spectra returned by the Thermal Emission Spectrometer (TES) are very well suited for monitoring the thermal structure and the distribution of aerosols and water vapor in the Mars atmosphere. Nadir-viewing spectra allow a global picture of the state of the Mars atmosphere on a daily basis. We report here on the observed annual cycle of the latitudinal dependence of atmospheric temperature, dust aerosols, water-ice clouds, and water vapor.

  6. Structural and emission properties of Tb3+-doped nitrogen-rich silicon oxynitride films

    NASA Astrophysics Data System (ADS)

    Labbé, C.; An, Y.-T.; Zatryb, G.; Portier, X.; Podhorodecki, A.; Marie, P.; Frilay, C.; Cardin, J.; Gourbilleau, F.

    2017-03-01

    Terbium doped silicon oxynitride host matrix is suitable for various applications such as light emitters compatible with CMOS technology or frequency converter systems for photovoltaic cells. In this study, amorphous Tb3+ ion doped nitrogen-rich silicon oxynitride (NRSON) thin films were fabricated using a reactive magnetron co-sputtering method, with various N2 flows and annealing conditions, in order to study their structural and emission properties. Rutherford backscattering (RBS) measurements and refractive index values confirmed the silicon oxynitride nature of the films. An electron microscopy analysis conducted for different annealing temperatures (T A) was also performed up to 1200 °C. Transmission electron microscopy (TEM) images revealed two different sublayers. The top layer showed porosities coming from a degassing of oxygen during deposition and annealing, while in the region close to the substrate, a multilayer-like structure of SiO2 and Si3N4 phases appeared, involving a spinodal decomposition. Upon a 1200 °C annealing treatment, a significant density of Tb clusters was detected, indicating a higher thermal threshold of rare earth (RE) clusterization in comparison to the silicon oxide matrix. With an opposite variation of the N2 flow during the deposition, the nitrogen excess parameter (Nex) estimated by RBS measurements was introduced to investigate the Fourier transform infrared (FTIR) spectrum behavior and emission properties. Different vibration modes of the Si–N and Si–O bonds have been carefully identified from the FTIR spectra characterizing such host matrices, especially the ‘out-of-phase’ stretching vibration mode of the Si–O bond. The highest Tb3+ photoluminescence (PL) intensity was obtained by optimizing the N incorporation and the annealing conditions. In addition, according to these conditions, the integrated PL intensity variation confirmed that the silicon nitride-based host matrix had a higher thermal threshold of rare

  7. Structural and emission properties of Tb(3+)-doped nitrogen-rich silicon oxynitride films.

    PubMed

    Labbé, C; An, Y-T; Zatryb, G; Portier, X; Podhorodecki, A; Marie, P; Frilay, C; Cardin, J; Gourbilleau, F

    2017-03-17

    Terbium doped silicon oxynitride host matrix is suitable for various applications such as light emitters compatible with CMOS technology or frequency converter systems for photovoltaic cells. In this study, amorphous Tb(3+) ion doped nitrogen-rich silicon oxynitride (NRSON) thin films were fabricated using a reactive magnetron co-sputtering method, with various N2 flows and annealing conditions, in order to study their structural and emission properties. Rutherford backscattering (RBS) measurements and refractive index values confirmed the silicon oxynitride nature of the films. An electron microscopy analysis conducted for different annealing temperatures (T A) was also performed up to 1200 °C. Transmission electron microscopy (TEM) images revealed two different sublayers. The top layer showed porosities coming from a degassing of oxygen during deposition and annealing, while in the region close to the substrate, a multilayer-like structure of SiO2 and Si3N4 phases appeared, involving a spinodal decomposition. Upon a 1200 °C annealing treatment, a significant density of Tb clusters was detected, indicating a higher thermal threshold of rare earth (RE) clusterization in comparison to the silicon oxide matrix. With an opposite variation of the N2 flow during the deposition, the nitrogen excess parameter (Nex) estimated by RBS measurements was introduced to investigate the Fourier transform infrared (FTIR) spectrum behavior and emission properties. Different vibration modes of the Si-N and Si-O bonds have been carefully identified from the FTIR spectra characterizing such host matrices, especially the 'out-of-phase' stretching vibration mode of the Si-O bond. The highest Tb(3+) photoluminescence (PL) intensity was obtained by optimizing the N incorporation and the annealing conditions. In addition, according to these conditions, the integrated PL intensity variation confirmed that the silicon nitride-based host matrix had a higher thermal threshold of rare earth

  8. Soil organic carbon dust emission: an omitted global source of atmospheric CO2.

    PubMed

    Chappell, Adrian; Webb, Nicholas P; Butler, Harry J; Strong, Craig L; McTainsh, Grant H; Leys, John F; Viscarra Rossel, Raphael A

    2013-10-01

    Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO(2)) budget because wind erosion contributes to the C cycle by removing selectively SOC from vast areas and transporting C dust quickly offshore; augmenting the net loss of C from terrestrial systems. However, the contribution of wind erosion to rates of C release and sequestration is poorly understood. Here, we describe how SOC dust emission is omitted from national C accounting, is an underestimated source of CO(2) and may accelerate SOC decomposition. Similarly, long dust residence times in the unshielded atmospheric environment may considerably increase CO(2) emission. We developed a first approximation to SOC enrichment for a well-established dust emission model and quantified SOC dust emission for Australia (5.83 Tg CO(2)-e yr(-1)) and Australian agricultural soils (0.4 Tg CO(2)-e yr(-1)). These amount to underestimates for CO(2) emissions of ≈10% from combined C pools in Australia (year = 2000), ≈5% from Australian Rangelands and ≈3% of Australian Agricultural Soils by Kyoto Accounting. Northern hemisphere countries with greater dust emission than Australia are also likely to have much larger SOC dust emission. Therefore, omission of SOC dust emission likely represents a considerable underestimate from those nations' C accounts. We suggest that the omission of SOC dust emission from C cycling and C accounting is a significant global source of uncertainty. Tracing the fate of wind-eroded SOC in the dust cycle is therefore essential to quantify the release of CO(2) from SOC dust to the atmosphere and the contribution of SOC deposition to downwind C sinks. © 2013 John Wiley & Sons Ltd.

  9. Updated atmospheric speciated mercury emissions from iron and steel production in China during 2000-2015

    NASA Astrophysics Data System (ADS)

    Wu, Qingru; Gao, Wei; Wang, Shuxiao; Hao, Jiming

    2017-09-01

    Iron and steel production (ISP) is one of the significant atmospheric Hg emission sources in China. Atmospheric mercury (Hg) emissions from ISP during 2000-2015 were estimated by using a technology-based emission factor method. To support the application of this method, databases of Hg concentrations in raw materials, technology development trends, and Hg removal efficiencies of air pollution control devices (APCDs) were constructed through national sampling and literature review. Hg input to ISP increased from 21.6 t in 2000 to 94.5 t in 2015. In the various types of raw materials, coking coal and iron concentrates contributed 35-46 and 25-32 % of the total Hg input. Atmospheric Hg emissions from ISP increased from 11.5 t in 2000 to 32.7 t in 2015 with a peak of 35.6 t in 2013. Pollution control promoted the increase in average Hg removal efficiency, from 47 % in 2000 to 65 % in 2015. During the study period, sinter/pellet plants and blast furnaces were the largest two emission processes. However, emissions from roasting plants and coke ovens cannot be ignored, which accounted for 22-34 % of ISP's emissions. Overall, Hg speciation shifted from 50/44/6 (gaseous elemental Hg (Hg0)/gaseous oxidized Hg (HgII)/particulate-bound Hg (Hgp)) in 2000 to 40/59/1 in 2015, which indicated a higher proportion of Hg deposition around the emission points. Future emissions of ISP were expected to decrease based on the comprehensive consideration crude-steel production, steel scrap utilization, energy saving, and pollution control measures.

  10. Atmospheric emission of mercury due to combustion of steam coal and domestic coal in China

    NASA Astrophysics Data System (ADS)

    Wang, Shaobin; Luo, Kunli

    2017-08-01

    To study the mercury emission due to the combustion of steam coal and domestic coal in China, we analyzed the mercury contents of coal, fly ash, bottom ash and sluicing water in thermal power plants, steam boilers as well as domestic coal-stoves, in Shaanxi, Shanxi, Shandong and Yunnan Provinces. This study conduct an estimate of the Hg emission rates from steam coal and domestic coal combustion based on the method of mass distribution ratio of fly ash and bottom ash. The results show that the Hg emission rate of coal combustion in thermal power plants is about 50.21% (electrostatic precipitators + wet flue gas desulfurization), and that in heating boilers is about 67.23%, and 92.28% in industrial boilers without flue gas desulphurisation equipment. Furthermore, Hg emission rate is 83.61% due to domestic coal combustion in coal-stoves. The Hg emission amount into the atmosphere from power and heat generation, industrial boilers, domestic coal-stoves and spontaneous combustion of coal gangue is roughly estimated to be 133 ± 4, 100 ± 17, 11 ± 0.1 and 47 ± 26 tons in China in 2014, respectively, and the total Hg emission amount from this paper is estimated at 292 tons. The trends of Hg emission in China from 1991 to 2014 show an accelerating growth after 2002. The proportion of mercury emission due to thermal power, heating generation and industrial energy utilization continuously increased. The atmospheric emission of mercury due to combustion of steam coal, domestic coal and coal gangue accounts nearly 50% in total anthropogenic Hg emissions in China, indicating one of the largest sources of Hg emission in China which should draw more public and scientific attention in the future.

  11. A model to calculate consistent atmospheric emission projections and its application to Spain

    NASA Astrophysics Data System (ADS)

    Lumbreras, Julio; Borge, Rafael; de Andrés, Juan Manuel; Rodríguez, Encarnación

    Global warming and air quality are headline environmental issues of our time and policy must preempt negative international effects with forward-looking strategies. As part of the revision of the European National Emission Ceilings Directive, atmospheric emission projections for European Union countries are being calculated. These projections are useful to drive European air quality analyses and to support wide-scale decision-making. However, when evaluating specific policies and measures at sectoral level, a more detailed approach is needed. This paper presents an original methodology to evaluate emission projections. Emission projections are calculated for each emitting activity that has emissions under three scenarios: without measures (business as usual), with measures (baseline) and with additional measures (target). The methodology developed allows the estimation of highly disaggregated multi-pollutant, consistent emissions for a whole country or region. In order to assure consistency with past emissions included in atmospheric emission inventories and coherence among the individual activities, the consistent emission projection (CEP) model incorporates harmonization and integration criteria as well as quality assurance/quality check (QA/QC) procedures. This study includes a sensitivity analysis as a first approach to uncertainty evaluation. The aim of the model presented in this contribution is to support decision-making process through the assessment of future emission scenarios taking into account the effect of different detailed technical and non-technical measures and it may also constitute the basis for air quality modelling. The system is designed to produce the information and formats related to international reporting requirements and it allows performing a comparison of national results with lower resolution models such as RAINS/GAINS. The methodology has been successfully applied and tested to evaluate Spanish emission projections up to 2020 for 26

  12. The efficiency and sensitivity analysis of observations for atmospheric transport model with emissions

    NASA Astrophysics Data System (ADS)

    Wu, Xueran; Elbern, Hendrik; Jacob, Birgit

    2015-04-01

    Air quality and climate change are influenced by the fluxes of green house gases, reactive emissions and aerosols in the atmosphere. But observations of the chemical states in the atmosphere typically have low temporal and spatial density. Therefore, many works are introduced to spatio-temporal data assimilation methods in atmospheric chemistry in recent years. There is no doubt that the optimization of the initial state is always of great importance for the improvement of predictive skill. However, specified to the chemistry transport model with high dependence on the emissions in the troposphere, the optimization of the initial state is no longer the only issue. The lack of the ability to observe and estimate surface emission fluxes and important inner atmospheric fluxes with necessary accuracy is a major roadblock of hampering the progress in predictive skills of the atmospheric transport model. However, in many cases, the better estimations for both the initial state and emission rates are not always obtained with certain observational network configurations via various popular data assimilation methods, such as the ensemble Kalman filter and smoother and 4D-variation. It leads to the waste of resource by optimizing the improper parameters or brings the inaccuracy of the optimization by unsuitable weight between the initial state and emission rates. Hence, in order to make a scientific and quantitative decision about which parameters to be optimized and how to balance them before any data assimilation procedure, we establish the dynamic model for emission rates with the constraint of diurnal profile shape and extend the state vector of atmospheric transport model so that the emission rates are included. Then, a theoretical approach, based on Kalman filter and smoother and their ensemble cases, to evaluate the potential improvement is introduced. By singular value decomposition, the efficiency of observations to optimize initial state and emission rates of the

  13. The impact of residential combustion emissions on atmospheric aerosol, human health and climate

    NASA Astrophysics Data System (ADS)

    Butt, E. W.; Rap, A.; Schmidt, A.; Reddington, C.; Scott, C.; Pringle, K.; Woodhouse, M.; Spracklen, D. V.

    2015-12-01

    Combustion of fuels in the residential sector for cooking and heating, results in the emission of aerosol and aerosol precursors that effect air quality, human health and climate. Residential emissions are dominated by the combustion of solid fuels which are the primary energy source for nearly half the world's population. Despite this importance, residential emissions are poorly quantified, as are their impacts on air quality and climate. We used a global aerosol microphysics model to simulate the impact of residential emissions on atmospheric aerosol in the year 2000, and evaluated simulated concentrations against surface observations of aerosol mass and number. Residential emissions make the largest contributions to surface particulate matter (PM2.5) concentrations in East Asia, South Asia and Eastern Europe, matching regions of greatest emissions. We used concentration response functions to estimate a global annual excess adult (> 30 years of age) premature mortality due to residential emissions of between 113, 300 and 827, 000 when uncertainties in both residential emissions and health effects of PM2.5 were accounted for. Premature mortality was greatest in Asia, with China and India accounting for 50% of simulated global excess mortality. Using an offline radiative transfer model, we show that residential emissions exerted a global annual mean direct radiative effect of between -66 mW m-2 and +21 mW m-2, accounting for uncertainties in emissions flux and assumed ratio of carbonaceous and sulphur emissions. Residential emissions exerted a negative global annual mean first aerosol indirect effect of between -52 mW m-2 and -16 mW m-2, which was found to be sensitive to the assumed size distribution of carbonaceous emissions. Our results demonstrate that reducing residential combustion emissions would have substantial benefits for human health through reductions in ambient PM2.5 concentrations.

  14. Global emissions of mercury to the atmosphere in 2005 and their 2020 scenarios

    NASA Astrophysics Data System (ADS)

    Pacyna, Jozef M.; Pacyna, Elisabeth G.; Sundseth, Kyrre; Munthe, John; Wilson, Simon; Leaner, Joy

    2010-05-01

    About the three quarters of the total anthropogenic emissions of mercury in the year 2005 estimated to be 1930 tonnes comes from sources where mercury is emitted as a by-product, and the rest is emitted during various applications of mercury. The largest emissions of Hg to the global atmosphere occur from combustion of fossil fuels, mainly coal in utility, industrial, and residential boilers (almost 47 %), followed by artisanal mining (almost 17 %), non-ferrous metal production, including gold production (13.5%) and cement production (about 9.5 %). Doing nothing for the improvement of the Hg emission reductions (so-called Status Quo - SQ scenario) will cause an increase of the emissions in 2020 by almost 100 % compared to the 2020 Extended Emission Control (EXEC) emission reduction scenario. Even larger increase is estimated when the 2020 SQ scenario of Hg emissions is compared with the 2020 Maximum Feasible Technical Reduction (MFTR) emission reduction scenario. The EXEC scenario assumes economic progress at a rate dependent on the future development of industrial technologies and emission control technologies, i.e. mercury-reducing technology currently generally employed throughout Europe and North America would be implemented elsewhere. It further assumes that emissions control measures currently implemented or committed to in Europe to reduce mercury emission to air or water would be implemented around the world. The MFTR scenario assumes implementation of all solutions/ measures leading to the maximum degree of reduction of mercury emissions and its loads discharged to any environment; cost is taken into account but only as a secondary consideration. Emissions of Hg in various industrial sectors, such as cement production and metal manufacturing in the year 2020 can be 2 to 3 times larger if nothing will be done to improve emission control in comparison with the EXEC scenario.

  15. Methane emissions in East Asia for 2000-2011 estimated using an atmospheric Bayesian inversion

    NASA Astrophysics Data System (ADS)

    Thompson, R. L.; Stohl, A.; Zhou, L. X.; Dlugokencky, E.; Fukuyama, Y.; Tohjima, Y.; Kim, S.-Y.; Lee, H.; Nisbet, E. G.; Fisher, R. E.; Lowry, D.; Weiss, R. F.; Prinn, R. G.; O'Doherty, S.; Young, D.; White, J. W. C.

    2015-05-01

    We present methane (CH4) emissions for East Asia from a Bayesian inversion of CH4 mole fraction and stable isotope (δ13C-CH4) measurements. Emissions were estimated at monthly resolution from 2000 to 2011. A posteriori, the total emission for East Asia increased from 43 ± 4 to 59 ± 4 Tg yr-1 between 2000 and 2011, owing largely to the increase in emissions from China, from 39 ± 4 to 54 ± 4 Tg yr-1, while emissions in other East Asian countries remained relatively stable. For China, South Korea, and Japan, the total emissions were smaller than the prior estimates (i.e., Emission Database for Global Atmospheric Research 4.2 FT2010 for anthropogenic emissions) by an average of 29%, 20%, and 23%, respectively. For Mongolia, Taiwan, and North Korea, the total emission was less than 2 Tg yr-1 and was not significantly different from the prior. The largest reductions in emissions, compared to the prior, occurred in summer in regions important for rice agriculture suggesting that this source is overestimated in the prior. Furthermore, an analysis of the isotope data suggests that the prior underestimates emissions from landfills and ruminant animals for winter 2010 to spring 2011 (no data available for other times). The inversion also found a lower average emission trend for China, 1.2 Tg yr-1 compared to 2.8 Tg yr-1 in the prior. This trend was not constant, however, and increased significantly after 2005, up to 2.0 Tg yr-1. Overall, the changes in emissions from China explain up to 40% of the increase in global emissions in the 2000s.

  16. Atmospheric dayglow diagnostics involving the O2(b-X) Atmospheric band emission: Global Oxygen and Temperature (GOAT) mapping

    NASA Astrophysics Data System (ADS)

    Slanger, T. G.; Pejaković, D. A.; Kostko, O.; Matsiev, D.; Kalogerakis, K. S.

    2017-03-01

    The terrestrial dayglow displays prominent emission features from the 0-0 and 1-1 bands of the O2 Atmospheric band system in the 760-780 nm region. We present an analysis of observations in this wavelength region recorded by the Space Shuttle during the Arizona Airglow Experiment. A major conclusion is that the dominant product of O(1D) + O2 energy transfer is O2(b, v = 1), a result that corroborates our previous laboratory studies. Moreover, critical to the interpretation of dayglow is the possible interference by N2 and N2+ bands in the 760-780 nm region, where the single-most important component is the N2 1PG 3-1 band that overlaps with the O2(b-X) 0-0 band. When present, this background must be accounted for to reveal the O2(b-X) 0-0 and 1-1 bands for altitudes at which the O2 and N2/N2+ emissions coincide. Finally, we exploit the very different collisional behavior of the two lowest O2(b) vibrational levels to outline a remote sensing technique that provides information on Atmospheric composition and temperature from space-based observations of the 0-0 and 1-1 O2 atmospheric bands.

  17. Regional Atmospheric Transport Code for Hanford Emission Tracking, Version 2(RATCHET2)

    SciTech Connect

    Ramsdell, James V.; Rishel, Jeremy P.

    2006-07-01

    This manual describes the atmospheric model and computer code for the Atmospheric Transport Module within SAC. The Atmospheric Transport Module, called RATCHET2, calculates the time-integrated air concentration and surface deposition of airborne contaminants to the soil. The RATCHET2 code is an adaptation of the Regional Atmospheric Transport Code for Hanford Emissions Tracking (RATCHET). The original RATCHET code was developed to perform the atmospheric transport for the Hanford Environmental Dose Reconstruction Project. Fundamentally, the two sets of codes are identical; no capabilities have been deleted from the original version of RATCHET. Most modifications are generally limited to revision of the run-specification file to streamline the simulation process for SAC.

  18. Helium emission from model flare layers. [of outer solar atmosphere

    NASA Technical Reports Server (NTRS)

    Kulander, J. I.

    1976-01-01

    The emission of visible and UV He I and He II line radiation from a plane-parallel model flare layer characterized by electron temperatures of 10,000 to 50,000 K and electron densities of 10 to the 10th power to 10 to the 15th power per cu cm is analyzed by solving the statistical-equilibrium equations for a 30-level He I-II-III system, using parametric representations of the line and continuum radiation fields. The atomic model was chosen to provide accurate solutions for the first two resonance lines of He I and He II as well as for the D3 and 10,830-A lines of He I. Reaction rates are discussed, and sample solutions to the steady-state population equations are given for a generally optically thin gas assumed to be irradiated over 2pi sr by a blackbody spectrum at 6000 K. Specific results are examined for ionization equilibrium, level populations, approximate optical depths of a 1000-km-thick flare layer, line intensities, and upper-level population rates.

  19. High altitude plume emissions in atmospheric-window region

    SciTech Connect

    Sharma, R.D.; Bakshi, P.; Sindoni, J.

    1989-02-01

    Quantum-Mechanical Spectator model (Impulse Approximation) is used to calculate the cross section for rotation-vibration excitation of CO during collision with atomic oxygen at relative velocity (energy) of 5 (1.3), 8 (3.3), 11 (5.3), and 14 km/s (10.2 eV). The calculation is carried out for initial CO vibrational level v=o and rotational levels J=O and J=10 and final vibrational levels v'=o - 6 and final rotational levels up to J'=100. It is shown that the final results are almost independent of the initial rotational level. The rotational distribution in the final vibrational levels is rather flat and cannot be described by a Maxwell-Boltzmann distribution. The final rotation-vibration distributions are translated into relative emission in the 4.7-micron region. The emitted radiation from each level shows an R-branch bandhead around 4.4 microns with P-branch extending beyond 6 microns. It is expected that carbon dioxide and water generated by the plumes at high altitudes, upon collision with atomic oxygen, would also emit band infrared radiation around 6, 4.3, and 2.7 microns.

  20. Helium emission from model flare layers. [of outer solar atmosphere

    NASA Technical Reports Server (NTRS)

    Kulander, J. I.

    1976-01-01

    The emission of visible and UV He I and He II line radiation from a plane-parallel model flare layer characterized by electron temperatures of 10,000 to 50,000 K and electron densities of 10 to the 10th power to 10 to the 15th power per cu cm is analyzed by solving the statistical-equilibrium equations for a 30-level He I-II-III system, using parametric representations of the line and continuum radiation fields. The atomic model was chosen to provide accurate solutions for the first two resonance lines of He I and He II as well as for the D3 and 10,830-A lines of He I. Reaction rates are discussed, and sample solutions to the steady-state population equations are given for a generally optically thin gas assumed to be irradiated over 2pi sr by a blackbody spectrum at 6000 K. Specific results are examined for ionization equilibrium, level populations, approximate optical depths of a 1000-km-thick flare layer, line intensities, and upper-level population rates.

  1. Remarkably improved field emission of TiO{sub 2} nanotube arrays by annealing atmosphere engineering

    SciTech Connect

    Liao, Ai-Zhen; Wang, Cheng-Wei Chen, Jian-Biao; Zhang, Xu-Qiang; Li, Yan; Wang, Jian

    2015-10-15

    Highlights: • TNAs were prepared by anodization and annealed in different atmospheres. • The crystal structure and electronic properties of the prepared TNAs were investigated. • The field emission of TNAs was highly dependent on annealing atmosphere. • A low turn-on of 2.44 V/μm was obtained for TNAs annealed in H{sub 2} atmosphere. - Abstract: Highly ordered TiO{sub 2} nanotube arrays (TNAs) were prepared by anodization, and followed by annealing in the atmospheres of Air, Vacuum, Ar, and H{sub 2}. The effect of annealing atmosphere on the crystal structure, composition, and electronic properties of TNAs were systematically investigated. Raman and EDS results indicated that the TNAs annealed in anaerobic atmospheres contained more oxygen vacancies, which result in the substantially improved electron transport properties and reduced work function. Moreover, it was found that the FE properties of TNAs were highly dependent on the annealing atmosphere. By engineering the annealing atmosphere, the turn-on field as low as 2.44 V/μm can be obtained from TNAs annealed in H{sub 2}, which was much lower than the value of 18.23 V/μm from the TNAs annealed in the commonly used atmosphere of Air. Our work suggests an instructive and attractive way to fabricate high performance TNAs field emitters.

  2. A black carbon emission data base for atmospheric chemistry and climate studies

    SciTech Connect

    Dignon, J.; Eddleman, H.E.; Penner, J.E.

    1994-10-01

    A global data base of black carbon emissions to the atmosphere from fossil fuel combustion has been compiled for the use in atmospheric chemistry and climate studies. The resolution provided is at 1{degree} latitude by 1{degree} longitude based on previous work by Matthews, Lemer et al., and Dignon. A more extensive description of the assumptions made and emission factors used in this data base can be found in Penner et al. The original work of Penner et al. provides the emissions inventory data on a 5{degree} by 5{degree} resolution. The units of emission for this updated version of the inventory yield a global total of 12.6 TgC/y and are given as the mass in metric tons of carbon for each 1{degree} x 1{degree} grid. It is important to note that this is not equivalent to a flux, in that the area of the grid boxes vary latitudinally. The emissions are expected to represent the emissions for a typical mid-1980s year. The distribution of emission is based on national totals and then mapped on to the 1{degree} x 1{degree} grid according to the updated population mapping of Logan. A description of this mapping procedure can be found in Dignon.

  3. Changes in Emissions in Megacities during the Past Decades: Impact on the Distribution of Atmospheric Compounds

    NASA Astrophysics Data System (ADS)

    Doumbia, E. H. T.; Granier, C.; Sindelarova, K.; Tilmes, S.; Bouarar, I.; Richter, A.; Hilboll, A.; Conley, A. J.; Garcia, R. R.; Kinnison, D. E.; Lamarque, J. F.; Marsh, D. R.; Smith, A. K.; Neely, R.; Turnock, S.

    2015-12-01

    The surface emissions of atmospheric compounds have changed dramatically in many world regions during the past decades. We will evaluate these changes through an analysis of different global and regional anthropogenic emissions inventories, focusing on several megacities. In European and North American megacities, surface emissions of chemical compounds have decreased significantly, while they have increased in many other megacities in different parts of the world. Simulations performed with the CAM4-Chem Community Earth System Model will be used to evaluate the impact of the changes in emissions on the distributions chemical compounds in different megacities. These simulations were performed as part of the Chemistry-Climate Model Initiative (CCMI), a project of the International Global Atmospheric Chemistry Project (IGAC). The analysis of the simulations will focus more particularly on nitrogen dioxide: this species has been observed by satellite measurements since the late 1990s. Model results and satellite observations will be analysed for everal megacities in Europe and North America, where strong emission controls have been implemented. Other megacities in China, India, Africa and South America, where few emission regulations have been enforced have seen large increases in their emissions: we will evaluate the consistency of the model simulations and satellite observations of NO2 in these cities.

  4. Mapping the spatial distribution of global anthropogenic mercury atmospheric emission inventories

    NASA Astrophysics Data System (ADS)

    Wilson, Simon J.; Steenhuisen, Frits; Pacyna, Jozef M.; Pacyna, Elisabeth G.

    This paper describes the procedures employed to spatially distribute global inventories of anthropogenic emissions of mercury to the atmosphere, prepared by Pacyna, E.G., Pacyna, J.M., Steenhuisen, F., Wilson, S. [2006. Global anthropogenic mercury emission inventory for 2000. Atmospheric Environment, this issue, doi:10.1016/j.atmosenv.2006.03.041], and briefly discusses the results of this work. A new spatially distributed global emission inventory for the (nominal) year 2000, and a revised version of the 1995 inventory are presented. Emissions estimates for total mercury and major species groups are distributed within latitude/longitude-based grids with a resolution of 1×1 and 0.5×0.5°. A key component in the spatial distribution procedure is the use of population distribution as a surrogate parameter to distribute emissions from sources that cannot be accurately geographically located. In this connection, new gridded population datasets were prepared, based on the CEISIN GPW3 datasets (CIESIN, 2004. Gridded Population of the World (GPW), Version 3. Center for International Earth Science Information Network (CIESIN), Columbia University and Centro Internacional de Agricultura Tropical (CIAT). GPW3 data are available at http://beta.sedac.ciesin.columbia.edu/gpw/index.jsp). The spatially distributed emissions inventories and population datasets prepared in the course of this work are available on the Internet at www.amap.no/Resources/HgEmissions/

  5. Characterization of Methane Emission Sources Using Genetic Algorithms and Atmospheric Transport Modeling

    NASA Astrophysics Data System (ADS)

    Cao, Y.; Cervone, G.; Barkley, Z.; Lauvaux, T.; Deng, A.; Miles, N.; Richardson, S.

    2016-12-01

    Fugitive methane emission rates for the Marcellus shale area are estimated using a genetic algorithm that finds optimal weights to minimize the error between simulated and observed concentrations. The overall goal is to understand the relative contribution of methane due to Shale gas extraction. Methane sensors were installed on four towers located in northeastern Pennsylvania to measure atmospheric concentrations since May 2015. Inverse Lagrangian dispersion model runs are performed from each of these tower locations for each hour of 2015. Simulated methane concentrations at each of the four towers are computed by multiplying the resulting footprints from the atmospheric simulations by thousands of emission sources grouped into 11 classes. The emission sources were identified using GIS techniques, and include conventional and unconventional wells, different types of compressor stations, pipelines, landfills, farming and wetlands. Initial estimates for each source are calculated based on emission factors from EPA and few regional studies. A genetic algorithm is then used to identify optimal emission rates for the 11 classes of methane emissions and to explore extreme events and spatial and temporal structures in the emissions associated with natural gas activities.

  6. Theoretical UV absorption spectra of hydrodynamically escaping O{sub 2}/CO{sub 2}-rich exoplanetary atmospheres

    SciTech Connect

    Gronoff, G.; Mertens, C. J.; Norman, R. B.; Maggiolo, R.; Wedlund, C. Simon; Bell, J.; Bernard, D.; Parkinson, C. J.; Vidal-Madjar, A.

    2014-06-20

    Characterizing Earth- and Venus-like exoplanets' atmospheres to determine if they are habitable and how they are evolving (e.g., equilibrium or strong erosion) is a challenge. For that endeavor, a key element is the retrieval of the exospheric temperature, which is a marker of some of the processes occurring in the lower layers and controls a large part of the atmospheric escape. We describe a method to determine the exospheric temperature of an O{sub 2}- and/or CO{sub 2}-rich transiting exoplanet, and we simulate the respective spectra of such a planet in hydrostatic equilibrium and hydrodynamic escape. The observation of hydrodynamically escaping atmospheres in young planets may help constrain and improve our understanding of the evolution of the solar system's terrestrial planets' atmospheres. We use the dependency of the absorption spectra of the O{sub 2} and CO{sub 2} molecules on the temperature to estimate the temperature independently of the total absorption of the planet. Combining two observables (two parts of the UV spectra that have a different temperature dependency) with the model, we are able to determine the thermospheric density profile and temperature. If the slope of the density profile is inconsistent with the temperature, then we infer the hydrodynamic escape. We address the question of the possible biases in the application of the method to future observations, and we show that the flare activity should be cautiously monitored to avoid large biases.

  7. Early Mars volcanic sulfur storage in the upper cryosphere and formation of transient SO2-rich atmospheres during the Hesperian

    NASA Astrophysics Data System (ADS)

    Schmidt, F.; Chassefière, E.; Tian, F.; Dartois, E.; Herri, J.-M.; Mousis, O.

    2016-11-01

    In a previous paper (Chassefière et al.), we have shown that most volcanic sulfur released to the early Mars atmosphere could have been trapped in the upper cryosphere under the form of CO2-SO2 clathrates. Huge amounts of sulfur, up to the equivalent of an 1 bar atmosphere of SO2, would have been stored in the Noachian upper cryosphere, then massively released to the atmosphere during the Hesperian due to rapidly decreasing CO2 pressure. It could have resulted in the formation of the large sulfate deposits observed mainly in Hesperian terrains, whereas no or little sulfates are found at the Noachian. In the present paper, we first clarify some aspects of our previous work. We discuss the possibility of a smaller cooling effect of sulfur particles, or even of a net warming effect. We point out the fact that CO2-SO2 clathrates formed through a progressive enrichment of a pre-existing reservoir of CO2 clathrates and discuss processes potentially involved in the slow formation of a SO2-rich upper cryosphere. We show that episodes of sudden destabilization at the Hesperian may generate 1000 ppmv of SO2 in the atmosphere and contribute to maintaining the surface temperature above the water freezing point.

  8. Global atmospheric emissions of polycyclic aromatic hydrocarbons from 1960 to 2008 and future predictions

    PubMed Central

    Shen, Huizhong; Huang, Ye; Wang, Rong; Zhu, Dan; Li, Wei; Shen, Guofeng; Wang, Bin; Zhang, Yanyan; Chen, Yuanchen; Lu, Yan; Chen, Han; Li, Tongchao; Sun, Kang; Li, Bengang; Liu, Wenxin; Liu, Junfeng; Tao, Shu

    2013-01-01

    Global atmospheric emissions of 16 polycyclic aromatic hydrocarbons (PAHs) from 69 major sources were estimated for a period from 1960 to 2030. Regression models and a technology split method were used to estimate country and time specific emission factors, resulting in a new estimate of PAH emission factor variation among different countries and over time. PAH emissions in 2007 were spatially resolved to 0.1°× 0.1° grids based on a newly developed global high-resolution fuel combustion inventory (PKU-FUEL-2007). The global total annual atmospheric emission of 16 PAHs in 2007 was 504 Gg (331-818 Gg, as interquartile range), with residential/commercial biomass burning (60.5%), open-field biomass burning (agricultural waste burning, deforestation, and wildfire, 13.6%), and petroleum consumption by on-road motor vehicles (12.8%) as the major sources. South (87 Gg), East (111 Gg), and Southeast Asia (52 Gg) were the regions with the highest PAH emission densities, contributing half of the global total PAH emissions. Among the global total PAH emissions, 6.19% of the emissions were in the form of high molecular weight carcinogenic compounds and the percentage of the carcinogenic PAHs was higher in developing countries (6.22%) than in developed countries (5.73%), due to the differences in energy structures and the disparities of technology. The potential health impact of the PAH emissions was greatest in the parts of the world with high anthropogenic PAH emissions, because of the overlap of the high emissions and high population densities. Global total PAH emissions peaked at 592 Gg in 1995 and declined gradually to 499 Gg in 2008. Total PAH emissions from developed countries peaked at 122 Gg in the early 1970s and decreased to 38 Gg in 2008. Simulation of PAH emissions from 2009 to 2030 revealed that PAH emissions in developed and developing countries would decrease by 46-71% and 48-64%, respectively, based on the six IPCC SRES scenarios. PMID:23659377

  9. Quantifying the effects of China's pollution control on atmospheric mercury emissions

    NASA Astrophysics Data System (ADS)

    Zhong, H.

    2014-12-01

    China has conducted series of air pollution control policies to reduce the pollutant emissions. Although not specifically for mercury (Hg), those policies are believed to have co-benefits on atmospheric Hg emission control. On the basis of field-tests data and updated information of energy conservation and emission control, we have developed multiple-year inventories of anthropogenic mercury emissions in China from 2005 to 2012. Three scenarios (scenario 0(S0), scenario 1(S1), scenario 2(S2)) with different emission controls and energy path are designed for prediction of the future Hg emissions for the country. In particular, comprehensive assessments has been conducted to evaluate the evolution of emission factors, recent emission trends, effects of control measures as well as the reliability of our results. The national total emissions of anthropogenic Hg are estimated to increase from 679.0 metric tons (t) in 2005 to 749.8 t in 2012, with the peak at 770.6 t in 2011. The annual growth rate of emissions can then be calculated at 2.1% during 2005-2011, much lower than that of energy consumption or economy of the country. Coal combustion, gold metallurgy and nonferrous metal smelting are the most significant Hg sources of anthropogenic origin, accounting together for 85% of national total emissions. Tightened air pollution controls in China should be important reasons for the smooth emission trends. Compared with 2005, 299 t Hg were reduced in 2010 from power plants, iron and steel smelting, nonferrous-smelting and cement production, benefiting from the improvement of control measures for those sectors. The speciation of Hg emissions is relatively stable for recent years, with the mass fractions of around 55%, 9% and 6% for Hg0, Hg2+ and Hgp respectively. Integrating the policy commitments on energy saving, different from the most conservative case S0, S2 shares the same energy path with S1, but includes more stringent emission control. Under those scenarios, we

  10. Global atmospheric emissions of polycyclic aromatic hydrocarbons from 1960 to 2008 and future predictions.

    PubMed

    Shen, Huizhong; Huang, Ye; Wang, Rong; Zhu, Dan; Li, Wei; Shen, Guofeng; Wang, Bin; Zhang, Yanyan; Chen, Yuanchen; Lu, Yan; Chen, Han; Li, Tongchao; Sun, Kang; Li, Bengang; Liu, Wenxin; Liu, Junfeng; Tao, Shu

    2013-06-18

    Global atmospheric emissions of 16 polycyclic aromatic hydrocarbons (PAHs) from 69 major sources were estimated for a period from 1960 to 2030. Regression models and a technology split method were used to estimate country and time specific emission factors, resulting in a new estimate of PAH emission factor variation among different countries and over time. PAH emissions in 2007 were spatially resolved to 0.1° × 0.1° grids based on a newly developed global high-resolution fuel combustion inventory (PKU-FUEL-2007). The global total annual atmospheric emission of 16 PAHs in 2007 was 504 Gg (331-818 Gg, as interquartile range), with residential/commercial biomass burning (60.5%), open-field biomass burning (agricultural waste burning, deforestation, and wildfire, 13.6%), and petroleum consumption by on-road motor vehicles (12.8%) as the major sources. South (87 Gg), East (111 Gg), and Southeast Asia (52 Gg) were the regions with the highest PAH emission densities, contributing half of the global total PAH emissions. Among the global total PAH emissions, 6.19% of the emissions were in the form of high molecular weight carcinogenic compounds and the percentage of the carcinogenic PAHs was higher in developing countries (6.22%) than in developed countries (5.73%), due to the differences in energy structures and the disparities of technology. The potential health impact of the PAH emissions was greatest in the parts of the world with high anthropogenic PAH emissions, because of the overlap of the high emissions and high population densities. Global total PAH emissions peaked at 592 Gg in 1995 and declined gradually to 499 Gg in 2008. Total PAH emissions from developed countries peaked at 122 Gg in the early 1970s and decreased to 38 Gg in 2008. Simulation of PAH emissions from 2009 to 2030 revealed that PAH emissions in developed and developing countries would decrease by 46-71% and 48-64%, respectively, based on the six IPCC SRES scenarios.

  11. Testing our Understanding of Biogenic Emissions and their Impacts on Atmospheric Composition above the Amazon Rainforest

    NASA Astrophysics Data System (ADS)

    Levine, J. G.; MacKenzie, A. R.; Squire, O. J.; Archibald, A. T.; Griffiths, P. T.; Oram, D.; Forster, G.; Lee, J. D.; Hopkins, J. R.; Bauguitte, S.; Demarco, C. F.; Artaxo, P.

    2014-12-01

    Biogenic volatile organic compounds (BVOCs) have a profound effect on atmospheric chemistry and composition, and thereby affect global air quality and climate. The Amazon rainforest constitutes an intense source of BVOCs and is thus a key location in which to probe these effects. Notable uncertainties remain regarding the amount of BVOCs emitted from the rainforest (a function of plant type, environmental conditions and physiological factors) and the quantitative influence they have on atmospheric oxidants, such as OH and O3 (a function of physical conditions and ambient atmospheric composition, not least the concentration of nitrogen oxides; NOx=NO+NO2). The effect that isoprene oxidation at low NOx concentrations has on the concentrations of OH and O3 proves a particular challenge to reproduce in atmospheric chemistry-transport models. We present here the results of a series of experiments aimed at testing our understanding of BVOC emissions from the Brazilian Amazon and the atmospheric chemistry stemming from these. We attempt to reproduce aircraft measurements of BVOCs, NOx and O3 from the South American Biomass Burning Analysis (SAMBBA) campaign in 2012, including those made close to the site of recent BVOC emission measurements, just north of Manaus, in the Cooperative LBA Atmospheric Regional Experiment (CLAIRE-UK). We compare the abilities of a variety of atmospheric chemistry mechanisms to capture the measurements in both a global atmospheric chemistry-transport model and a trajectory model of chemistry and transport. The exploration in both Eulerian and Lagrangian frameworks, with their contrasting treatments of mixing, is pertinent in view of: the sensitivity that the chemistry stemming from BVOCs shows to ambient NOx concentrations; and the episodic influence of anthropogenic emissions in this environment, for example from Manaus.

  12. Short-chain oxygenated VOCs: Emission and uptake by plants and atmospheric sources, sinks, and concentrations

    NASA Astrophysics Data System (ADS)

    Seco, Roger; Peñuelas, Josep; Filella, Iolanda

    Emissions of volatile organic compounds (VOCs) have multiple atmospheric implications and play many roles in plant physiology and ecology. Among these VOCs, growing interest is being devoted to a group of short-chain oxygenated VOCs (oxVOCs). Technology improvements such as proton transfer reaction-mass spectrometry are facilitating the study of these hydrocarbons and new data regarding these compounds is continuously appearing. Here we review current knowledge of the emissions of these oxVOCs by plants and the factors that control them, and also provide an overview of sources, sinks, and concentrations found in the atmosphere. The oxVOCs reviewed here are formic and acetic acids, acetone, formaldehyde, acetaldehyde, methanol, and ethanol. In general, because of their water solubility (low gas-liquid partitioning coefficient), the plant-atmosphere exchange is stomatal-dependent, although it can also take place via the cuticle. This exchange is also determined by atmospheric mixing ratios. These compounds have relatively long atmospheric half-lives and reach considerable concentrations in the atmosphere in the range of ppbv. Likewise, under non-stressed conditions plants can emit all of these oxVOCs together at fluxes ranging from 0.2 up to 4.8 μg(C)g -1(leaf dry weight)h -1 and at rates that increase several-fold when under stress. Gaps in our knowledge regarding the processes involved in the synthesis, emission, uptake, and atmospheric reactivity of oxVOCs precludes the clarification of exactly what is conditioning plant-atmosphere exchange—and also when, how, and why this occurs—and these lacunae therefore warrant further research in this field.

  13. The wash-out of emissions from the atmosphere by precipitation

    Treesearch

    Ladislav Hanu& #154; ka; Eva Nov& #225; kov& #225; ; Nov& #225; kov& #225; Eva NO-VALUE

    1976-01-01

    We investigated the mechanism and dynamics of solid particles, emissions, and the concentrations of sulphur dioxide as integral components of the contamination of atmosphere. The only way of decontamination is the wash-out by precipitation (solid - snow, liquid - rain). We started from the items of information acquired during the studies of snow acidity in mountain...

  14. Future changes in biogenic isoprene emissions: how might they affect regional and global atmospheric chemistry?

    Treesearch

    Christine Wiedinmyer; Xuexi Tie; Alex Guenther; Ron Neilson; Claire. Granier

    2006-01-01

    Isoprene is emitted from vegetation to the atmosphere in significant quantities, and it plays an important role in the reactions that control tropospheric oxidant concentrations. As future climatic and land-cover changes occur, the spatial and temporal variations, as well as the magnitude of these biogenic isoprene emissions, are expected to change. This paper presents...

  15. Thermal emission spectra of the Earth and atmosphere from the Nimbus 4 Michelson interferometer experiment.

    PubMed

    Hanel, R A; Conrath, B J

    1970-10-10

    Profiles of atmospheric temperature, humidity and ozone can be recovered from the thermal emission spectra in the interval 400 to 1,500 cm(-1) obtained from the Nimbus 4 satellite. The spectra can also be used to study surface restrahlen effects and other geophysical and meteorological phenomena.

  16. Demonstration of a mobile Flux Laboratory for the Atmospheric Measurement of Emissions (FLAME) to assess emissions inventories.

    PubMed

    Moore, Tim O; Doughty, David C; Marr, Linsey C

    2009-02-01

    The advancement of air quality science and the development of effective air quality management plans require accurate estimates of emissions. In response to the need for new approaches to quantifying emissions, we have designed a mobile Flux Lab for the Atmospheric Measurement of Emissions (FLAME) that uses eddy covariance for the direct measurement of anthropogenic emissions at the neighborhood scale. To demonstrate the FLAME's capabilities, we have deployed it in the Huntington-Ashland region at the borders of Ohio, Kentucky and West Virginia. This area routinely experiences high ozone and fine particulate matter (PM(2.5)) concentrations and is home to a significant amount of industrial activity, including coal storage and transport. Experiments focused on carbon dioxide (CO(2)), nitrogen oxides (NO(x)) and fine particulate matter (PM(2.5)). Spikes in CO(2) and NO(x) concentrations were correlated with the passage of trains and barges through the FLAME's footprint. Calculated barge emission factors ranged from 49 to 76 kg NO(x) tonne(-1) fuel and agreed well with previously published values. Fluxes measured at three sites in the town of Worthington were mainly positive. They ranged between -6.5 to 29 mg m(-2) s(-1) for CO(2) and -9.7 x 10(-5) to 9.1 x 10(-5) mg m(-2) s(-1) for PM(2.5). We illustrate how the measurements can be compared to emissions inventories on a per capita basis for greenhouse gases and countywide for other pollutants. The results show that a mobile eddy covariance system can be used successfully to measure fluxes of multiple pollutants in a variety of settings. This alternative method for estimating emissions can be a useful tool for assessing uncertainties in emissions inventories and for improving their accuracy.

  17. Gridded atmospheric emission inventory of 2,3,7,8-TCDD in China

    NASA Astrophysics Data System (ADS)

    Huang, Tao; Tian, Chongguo; Zhang, Kai; Gao, Hong; Li, Yi-Fan; Ma, Jianmin

    2015-05-01

    Establishment of the dioxins emission inventory has been considered as a crucial step toward risk assessment and elimination of dioxins contaminations. Based on a total dioxin emission inventory in China from different emission categories in 2004, this study created a gridded emission inventory of 2,3,7,8-TCDD, the most toxic congener in dioxins, in China in 2009 with a 1/4° longitude by 1/4° latitude resolution. It was estimated that annually total 371 ± 53 g (average ± standard deviation) of 2,3,7,8-TCDD was released into the atmosphere in 2009 over China, increasing approximately by 37% compared with its emission in 2004. Differing from most developed countries where municipal waste incinerations were regarded as a major atmospheric emission source, in China ferrous and non-ferrous metal production made the largest contribution to 2,3,7,8-TCDD air emission (138 ± 16 g), followed by waste incineration (109 ± 12 g), power and heating generation (62 ± 9 g), and production of mineral products (47 ± 8 g). The rest of sources contributed approximately 3% to the total 2,3,7,8-TCDD emission in 2009. Iron and steel industries are mainly located in Beijing-Tianjin-Hebei (BTH) and Yangtze River Delta (YRD) regions, whereas waste incinerators are mainly located in Pearl River Delta (PRD) region. Higher 2,3,7,8-TCDD emissions were found in these three regions. While the BTH, YRD, and PRD accounted for only about 4% of total land area of China, they contributed approximately 14%, 15%, and 5% to the total 2,3,7,8-TCDD emission in 2009 in China, respectively.

  18. Atmospheric mercury emissions in Australia from anthropogenic, natural and recycled sources

    NASA Astrophysics Data System (ADS)

    Nelson, Peter F.; Morrison, Anthony L.; Malfroy, Hugh J.; Cope, Martin; Lee, Sunhee; Hibberd, Mark L.; Meyer, C. P. (Mick); McGregor, John

    2012-12-01

    The United Nations Environment Programme (UNEP) has begun a process of developing a legally binding instrument to manage emissions of mercury from anthropogenic sources. The UNEP Governing Council has concluded that there is sufficient evidence of significant global adverse impacts from mercury to warrant further international action; and that national, regional and global actions should be initiated as soon as possible to identify populations at risk and to reduce human generated releases. This paper describes the development of, and presents results from, a comprehensive, spatially and temporally resolved inventory of atmospheric mercury emissions from the Australian landmass. Results indicate that the best estimate of total anthropogenic emissions of mercury to the atmosphere in 2006 was 15 ± 5 tonnes. Three industrial sectors contribute substantially to Australian anthropogenic emissions: gold smelting (˜50%, essentially from a single site/operation), coal combustion in power plants (˜15%) and alumina production from bauxite (˜12%). A diverse range of other sectors contribute smaller proportions of the emitted mercury, but industrial emissions account for around 90% of total anthropogenic mercury emissions. The other sectors include other industrial sources (mining, smelting, and cement production) and the use of products containing mercury. It is difficult to determine historical trends in mercury emissions given the large uncertainties in the data. Estimates for natural and re-emitted emissions from soil, water, vegetation and fires are made using meteorological models, satellite observations of land cover and soil and vegetation type, fuel loading, fire scars and emission factors which account for the effects of temperature, insolation and other environmental variables. These natural and re-emitted sources comfortably exceed the anthropogenic emissions, and comprise 4-12 tonnes per year from vegetation, 70-210 tonnes per year from soils, and 21-63 tonnes

  19. Theoretical Investigation of the Effects of Atmospheric Gravity Waves on the Hydroxyl Emissions of the Atmosphere.

    DTIC Science & Technology

    1979-12-31

    of response etc. have been treated by Thome (1968), Testud and Francois (1971), Klostermeyer (1972a,b) and Porter and Tuan (1974). With the ex...and provided a suitable physical -2- -- 2 - -- explanation. Subsequent theoretical papers by Testud and Francois (1971), Klostermeyer (1971a,b) and...01 airglow emission intensity on Oct. 28-29, 1961, Nature 195, 481-482 (1962). (26) Testud , J. and P. Francois, Importance of diffusion processes in

  20. Can the envisaged reductions of fossil fuel CO2 emissions be detected by atmospheric observations?

    PubMed

    Levin, Ingeborg; Rödenbeck, Christian

    2008-03-01

    The lower troposphere is an excellent receptacle, which integrates anthropogenic greenhouse gases emissions over large areas. Therefore, atmospheric concentration observations over populated regions would provide the ultimate proof if sustained emissions changes have occurred. The most important anthropogenic greenhouse gas, carbon dioxide (CO(2)), also shows large natural concentration variations, which need to be disentangled from anthropogenic signals to assess changes in associated emissions. This is in principle possible for the fossil fuel CO(2) component (FFCO(2)) by high-precision radiocarbon ((14)C) analyses because FFCO(2) is free of radiocarbon. Long-term observations of (14)CO(2) conducted at two sites in south-western Germany do not yet reveal any significant trends in the regional fossil fuel CO(2) component. We rather observe strong inter-annual variations, which are largely imprinted by changes of atmospheric transport as supported by dedicated transport model simulations of fossil fuel CO(2). In this paper, we show that, depending on the remoteness of the site, changes of about 7-26% in fossil fuel emissions in respective catchment areas could be detected with confidence by high-precision atmospheric (14)CO(2) measurements when comparing 5-year averages if these inter-annual variations were taken into account. This perspective constitutes the urgently needed tool for validation of fossil fuel CO(2) emissions changes in the framework of the Kyoto protocol and successive climate initiatives.

  1. Atmospheric emissivity with clear sky computed by E-Trans/HITRAN

    NASA Astrophysics Data System (ADS)

    Mendoza, Víctor M.; Villanueva, Elba E.; Garduño, René; Sánchez-Meneses, Oscar

    2017-04-01

    The vertical profiles of temperature and pressure from the International Standard Atmosphere, together with the mixing ratio profiles of the main greenhouse effect gases (GG), namely water vapour, CO2 , CH4 , N2 O and stratospheric O3 , are used to determine the downward emissivity of long wave radiation by cloudless atmosphere, by means of the spectral calculator E-Trans with the HITRAN (high-resolution transmission) database. We make a review of emissivity parameterizations, reported by several authors, in terms of the surface vapour pressure and surface air temperature. We compute vertically weighted averages of temperature and pressure, also parameterize the CH4 , N2 O and O3 mixing ratio profiles, in order to adapt these variables as required by the E-Trans/HITRAN. Our results of emissivity for the corresponding vapour pressures agree well with those obtained by the reviewed authors. With this method, the emissivity can be computed at a regional scale and towards the future global warming, according to the IPCC temperature projections that will also increase the atmospheric humidity, from the emission scenarios of GG.

  2. Short and Long Term Impacts of Forest Bioenergy Production on Atmospheric Carbon Dioxide Emissions

    NASA Astrophysics Data System (ADS)

    Hudiburg, T.; Law, B. E.; Luyssaert, S.; Thornton, P. E.

    2011-12-01

    Temperate forest annual net uptake of CO2 from the atmosphere is equivalent to ~16% of the annual fossil fuel emissions in the United States. Mitigation strategies to reduce emissions of carbon dioxide have lead to investigation of alternative sources of energy including forest biomass. The prospect of forest derived bioenergy has led to implementation of new forest management strategies based on the assumption that they will reduce total CO2 emissions to the atmosphere by simultaneously reducing the risk of wildfire and substituting for fossil fuels. The benefit of managing forests for bioenergy substitution of fossil fuels versus potential carbon sequestration by reducing harvest needs to be evaluated. This study uses a combination of Federal Forest Inventory data (FIA), remote sensing, and a coupled carbon-nitrogen ecosystem process model (CLM4-CN) to predict net atmospheric CO2 emissions from forest thinning for bioenergy production in Oregon under varying future management and climate scenarios. We use life-cycle assessment (LCA) incorporating both the forest and forest product sinks and sources of carbon dioxide. Future modeled results are compared with a reduced harvest scenario to determine the potential for increased carbon sequestration in forest biomass. We find that Oregon forests are a current strong sink of 7.5 ± 1.7 Tg C yr-1 or 61 g C m-2 yr-1. (NBP; NEP minus removals from fire and harvest). In the short term, we find that carbon dynamics following harvests for fire prevention and large-scale bioenergy production lead to 2-15% higher emissions over the next 20 years compared to current management, assuming 100% effectiveness of fire prevention. Given the current sink strength, analysis of the forest sector in Oregon demonstrates that increasing harvest levels by all practices above current business-as-usual levels increases CO2 emissions to the atmosphere as long as the region's sink persists. In the long-term, we find that projected changes in

  3. Reconstruction of flux and altitude of volcanic SO2 emissions from satellite observations: implications for volcanological and atmospherical studies.

    NASA Astrophysics Data System (ADS)

    Boichu, Marie; Clarisse, Lieven; Péré, Jean-Christophe; Herbin, Hervé; Goloub, Philippe; Thieuleux, François; Khvorostyanov, Dmitry; Ducos, Fabrice; Clerbaux, Cathy; Tanré, Didier

    2016-04-01

    Volcanic sulphur dioxide (SO2) degassing is a crucial indicator of the sub-surface volcanic activity, which is widely used today for volcano monitoring and hazard assessment purposes. Volcanic SO2 is also important regarding atmospherical studies. More easily detectable from space, SO2 can be used as a proxy of the presence of ash to anticipate air traffic issues caused by explosive eruptions. Moreover, volcanic SO2 strongly impacts air quality but also climate following its conversion to radiatively-active sulphate aerosols. However, the accurate assessment of these various impacts is currently hampered by the poor knowledge of volcanic SO2 emissions, which can substantially vary with time, in terms of flux and altitude. To fulfil this need, we propose a strategy relying on satellite observations, which consequently allows for monitoring the eruptive activity of any remote volcano. The method consists in assimilating snapshots of the SO2 load, provided by infrared or ultraviolet satellite observations, in an inversion scheme that involves the use of a chemistry-transport model to describe the dispersion of SO2 released in the atmosphere. Applied on Eyjafjallajökull (Iceland) and Etna (Italy) eruption case-studies, this procedure allows for retrospectively reconstructing both the flux and altitude of the SO2 emissions with an hourly resolution. We show the improvement gained in the simulations and forecasts of the location and mass load of volcanic SO2 clouds using such a detailed reconstruction of emissions. For calibration-validation purpose, we compared our satellite-derived time-series of the SO2 flux with ground-based observations available on Etna. This comparison indicates a good agreement during ash-poor phases of the eruption. However, large discrepancies are observed during the ash-rich paroxysmal phase as a result of enhanced plume opacity affecting ground-based ultraviolet spectroscopic retrievals. Therefore, the SO2 emission rate derived from the

  4. Optical Emission Spectroscopy of an Atmospheric Pressure Plasma Jet During Tooth Bleaching Gel Treatment.

    PubMed

    Šantak, Vedran; Zaplotnik, Rok; Tarle, Zrinka; Milošević, Slobodan

    2015-11-01

    Optical emission spectroscopy was performed during atmospheric pressure plasma needle helium jet treatment of various tooth-bleaching gels. When the gel sample was inserted under the plasma plume, the intensity of all the spectral features increased approximately two times near the plasma needle tip and up to two orders of magnitude near the sample surface. The color change of the hydroxylapatite pastille treated with bleaching gels in conjunction with the atmospheric pressure plasma jet was found to be in correlation with the intensity of OH emission band (309 nm). Using argon as an additive to helium flow (2 L/min), a linear increase (up to four times) of OH intensity and, consequently, whitening (up to 10%) of the pastilles was achieved. An atmospheric pressure plasma jet activates bleaching gel, accelerates OH production, and accelerates tooth bleaching (up to six times faster).

  5. Effects of simulated spring thaw of permafrost from mineral cryosol on CO2 emissions and atmospheric CH4 uptake

    NASA Astrophysics Data System (ADS)

    Stackhouse, Brandon T.; Vishnivetskaya, Tatiana A.; Layton, Alice; Chauhan, Archana; Pfiffner, Susan; Mykytczuk, Nadia C.; Sanders, Rebecca; Whyte, Lyle G.; Hedin, Lars; Saad, Nabil; Myneni, Satish; Onstott, Tullis C.

    2015-09-01

    Previous studies investigating organic-rich tundra have reported that increasing biodegradation of Arctic tundra soil organic carbon (SOC) under warming climate regimes will cause increasing CO2 and CH4 emissions. Organic-poor, mineral cryosols, which comprise 87% of Arctic tundra, are not as well characterized. This study examined biogeochemical processes of 1 m long intact mineral cryosol cores (1-6% SOC) collected in the Canadian high Arctic. Vertical profiles of gaseous and aqueous chemistry and microbial composition were related to surface CO2 and CH4 fluxes during a simulated spring/summer thaw under light versus dark and in situ versus water saturated treatments. CO2 fluxes attained 0.8 ± 0.4 mmol CO2 m-2 h-1 for in situ treatments, of which 85 ± 11% was produced by aerobic SOC oxidation, consistent with field observations and metagenomic analyses indicating aerobic heterotrophs were the dominant phylotypes. The Q10 values of CO2 emissions ranged from 2 to 4 over the course of thawing. CH4 degassing occurred during initial thaw; however, all cores were CH4 sinks at atmospheric concentration CH4. Atmospheric CH4 uptake rates ranged from -126 ± 77 to -207 ± 7 nmol CH4 m-2 h-1 with CH4 consumed between 0 and 35 cm depth. Metagenomic and gas chemistry analyses revealed that high-affinity Type II methanotrophic sequence abundance and activity were highest between 0 and 35 cm depth. Microbial sulfate reduction dominated the anaerobic processes, outcompeting methanogenesis for H2 and acetate. Fluxes, microbial community composition, and biogeochemical rates indicate that mineral cryosols of Axel Heiberg Island act as net CO2 sources and atmospheric CH4 sinks during summertime thaw under both in situ and water saturated states.

  6. Atmospheric impacts of black carbon emission reductions through the strategic use of biodiesel in California.

    PubMed

    Zhang, Hongliang; Magara-Gomez, Kento T; Olson, Michael R; Okuda, Tomoaki; Walz, Kenneth A; Schauer, James J; Kleeman, Michael J

    2015-12-15

    The use of biodiesel as a replacement for petroleum-based diesel fuel has gained interest as a strategy for greenhouse gas emission reductions, energy security, and economic advantage. Biodiesel adoption may also reduce particulate elemental carbon (EC) emissions from conventional diesel engines that are not equipped with after-treatment devices. This study examines the impact of biodiesel blends on EC emissions from a commercial off-road diesel engine and simulates the potential public health benefits and climate benefits. EC emissions from the commercial off-road engine decreased by 76% when ultra-low sulfur commercial diesel (ULSD) fuel was replaced by biodiesel. Model calculations predict that reduced EC emissions translate directly into reduced EC concentrations in the atmosphere, but the concentration of secondary particulate matter was not directly affected by this fuel change. Redistribution of secondary particulate matter components to particles emitted from other sources did change the size distribution and therefore deposition rates of those components. Modification of meteorological variables such as water content and temperature influenced secondary particulate matter formation. Simulations with a source-oriented WRF/Chem model (SOWC) for a severe air pollution episode in California that adopted 75% biodiesel blended with ULSD in all non-road diesel engines reduced surface EC concentrations by up to 50% but changed nitrate and total PM2.5 mass concentrations by less than ±5%. These changes in concentrations will have public health benefits but did not significantly affect radiative forcing at the top of the atmosphere. The removal of EC due to the adoption of biodiesel produced larger coatings of secondary particulate matter on other atmospheric particles containing residual EC leading to enhanced absorption associated with those particles. The net effect was a minor change in atmospheric optical properties despite a large change in atmospheric EC

  7. Experimental and Numerical Modelling of CO2 Atmospheric Dispersion in Hazardous Gas Emission Sites.

    NASA Astrophysics Data System (ADS)

    Gasparini, A.; sainz Gracia, A. S.; Grandia, F.; Bruno, J.

    2015-12-01

    Under stable atmospheric conditions and/or in presence of topographic depressions, CO2 concentrations can reach high values resulting in lethal effect to living organisms. The distribution of denser than air gases released from the underground is governed by gravity, turbulence and dispersion. Once emitted, the gas distribution is initially driven by buoyancy and a gas cloud accumulates on the ground (gravitational phase); with time the density gradient becomes less important due to dispersion or mixing and gas distribution is mainly governed by wind and atmospheric turbulence (passive dispersion phase). Natural analogues provide evidences of the impact of CO2 leakage. Dangerous CO2 concentration in atmosphere related to underground emission have been occasionally reported although the conditions favouring the persistence of such a concentration are barely studied.In this work, the dynamics of CO2 in the atmosphere after ground emission is assessed to quantify their potential risk. Two approaches have been followed: (1) direct measurement of air concentration in a natural emission site, where formation of a "CO2 lake" is common and (2) numerical atmospheric modelling. Two sites with different morphology were studied: (a) the Cañada Real site, a flat terrain in the Volcanic Field of Campo de Calatrava (Spain); (b) the Solforata di Pomezia site, a rough terrain in the Alban Hills Volcanic Region (Italy). The comparison between field data and model calculations reveal that numerical dispersion models are capable of predicting the formation of CO2 accumulation over the ground as a consequence of underground gas emission. Therefore, atmospheric modelling could be included as a valuable methodology in the risk assessment of leakage in natural degassing systems and in CCS projects. Conclusions from this work provide clues on whether leakage may be a real risk for humans and under which conditions this risk needs to be included in the risk assessment.

  8. What atmospheric measurements tell us about methane emissions in the East Siberian Arctic Shelf

    NASA Astrophysics Data System (ADS)

    Bousquet, P.; Berchet, A.; Pison, I.; Locatelli, R.; Chevallier, F.; Paris, J. D.; Dlugokencky, E. J.; Laurila, T. J. A.; Hatakka, J.; Viisanen, Y.; Worthy, D. E. J.; Nisbet, E. G.; Fisher, R. E.; France, J. L.; Lowry, D.; Ivakhov, V.

    2015-12-01

    Atmospheric methane is the second anthropogenic greenhouse gas after carbon dioxide, contributing 20% to climate forcing since pre-industrial times. It is emitted by a variety of surface sources and mostly destroyed in the atmosphere by the OH radicals. Although methane emission types are identified, large uncertainties remain in their regional quantification. This is the case in the Arctic, where natural methane emissions are significant and estimated in the range of 11-51 TgCH4.y-1 for lands and 1-12 TgCH4.y-1 for ocean (north of 60°N). Subsea permafrost and hydrates in the East Siberian Arctic Ocean Continental Shelf (ESAS) constitute a substantial methane pool, and a potentially large source of methane to the atmosphere. Previous studies based on interpolated oceanographic campaigns estimated atmospheric emissions from this area at 8-17 TgCH4.y-1. Here, we propose insights based on atmospheric observations to evaluate these estimates. Isotopic observations suggest a biogenic origin (either terrestrial or marine) of air masses originating from ESAS during summer. We compare high-resolution simulations of atmospheric methane mole fractions to continuous methane observations to confirm the high variability and heterogeneity of the methane releases from ESAS. Simulated mole fractions including a 8 TgCH4.y-1 source from ESAS are found largely over-estimated compared to the observations in winter, whereas summer signals are more consistent with each others. Based on a statistical analysis of the observations and of the simulations, we find that methane emissions from ESAS are in a range of 0.5-4.5 TgCH4.y-1.

  9. Emission of atmospheric pollutants out of Africa - Analysis of CARIBIC aircraft air samples

    NASA Astrophysics Data System (ADS)

    Thorenz, Ute R.; Baker, Angela K.; Schuck, Tanja; van Velthoven, Peter F. J.; Ziereis, Helmut; Brenninkmeijer, Carl A. M.

    2014-05-01

    Africa is the single largest continental source of biomass burning (BB) emissions. The burning African savannas and tropical forests are a source for a wide range of chemical species, which are important for global atmospheric chemistry, especially for the pristine Southern Hemisphere. Emitted compounds include carbon monoxide (CO), nitrogen oxides (NOx), hydrocarbons, oxygenated hydrocarbons and particles. Deep convection over Central Africa transports boundary layer emissions to the free troposphere making aircraft-based observations useful for investigation of surface emissions and examination of transport and chemistry processes over Africa The CARIBIC project (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container, www.caribic-atmosphere.com part of IAGOS www.iagos.org) is a long term atmospheric measurement program using an instrument container deployed aboard a Lufthansa Airbus A340-600 for a monthly sequence of long-distance passenger flights. Besides the online measurements mixing ratios of greenhouse gases and a suite of C2-C8 non methane hydrocarbons (NMHCs) are measured from flask samples collected at cruise altitude. During northern hemispheric winter 2010/2011 CARIBIC flights took place from Frankfurt to Cape Town and Johannesburg in South Africa. Several BB tracers like methane, CO and various NMHCs were found to be elevated over tropical Africa. Using tracer-CO- and tracer-NOy-correlations emissions were characterized. The NMHC-CO correlations show monthly changing slopes, indicating a change in burned biomass, major fire stage, source region and/or other factors influencing NMHC emissions. To expand our analysis of emission sources a source region data filter was used, based on backward trajectories calculated along the flight tracks. Taking all CARIBIC samples into account having backward trajectories to the African boundary layer the dataset was enlarged from 77 to 168 samples. For both datasets tracer

  10. Atmospheric dispersion modeling to assess the tracer dilution method for measuring landfill methane emissions

    NASA Astrophysics Data System (ADS)

    Taylor, D.; Delkash, M.; Chow, F. K.; Imhoff, P. T.

    2014-12-01

    Landfill methane emissions are difficult to estimate due to limited observation and uncertainty of the data. The tracer dilution method is a widely used approach that uses a tracer gas released at a known rate from one or more point sources, and the ratio of the concentration of tracer gas to concentration of methane measured at a downwind point is used to calculate the methane emissions rate. Here we use a high-resolution atmospheric model to examine the set-up of the tracer dilution method and its effects on the accuracy of methane emissions calculations. This method relies on optimal weather conditions and is limited by availability of locations where downwind measurements can be taken. Therefore using limited measurements taken with this method to estimate annual landfill emissions will yield totals of dubious accuracy. The Weather Research and Forecasting model (WRF) is a mesoscale meteorological model that is commonly used for atmospheric research as well as operational forecasts. Here, a scalar tracking subroutine is added to WRF to simulate the methane emissions from the surface of the landfill and the tracer gas from point sources. Using this model, many different tracer release configurations (number and placement of tracer release points and downwind measurement locations) are simulated and compared. Wind speed dependence of methane emissions is examined by prescribing surface flux as a function of local wind speed. The tracer dilution method can only collect landfill emissions data during ideal weather conditions, so modeling emissions during non-ideal conditions will give a better idea of how to predict total annual emissions taking into account the emissions on days when emissions cannot accurately be measured. The WRF output is compared to output of an analogous model adapted from the existing atmospheric model Advanced Regional Prediction System (ARPS) and to observation data from Sandtown Landfill in Delaware, USA. Future work includes adding

  11. Abrupt reversal in emissions and atmospheric abundance of HCFC-133a (CF3CH2Cl)

    NASA Astrophysics Data System (ADS)

    Vollmer, Martin K.; Rigby, Matt; Laube, Johannes C.; Henne, Stephan; Rhee, Tae Siek; Gooch, Lauren J.; Wenger, Angelina; Young, Dickon; Steele, L. Paul; Langenfelds, Ray L.; Brenninkmeijer, Carl A. M.; Wang, Jia-Lin; Ou-Yang, Chang-Feng; Wyss, Simon A.; Hill, Matthias; Oram, David E.; Krummel, Paul B.; Schoenenberger, Fabian; Zellweger, Christoph; Fraser, Paul J.; Sturges, William T.; O'Doherty, Simon; Reimann, Stefan

    2015-10-01

    Hydrochlorofluorocarbon HCFC-133a (CF3CH2Cl) is an anthropogenic compound whose consumption for emissive use is restricted under the Montreal Protocol. A recent study showed rapidly increasing atmospheric abundances and emissions. We report that, following this rise, the atmospheric abundance and emissions have declined sharply in the past three years. We find a Northern Hemisphere HCFC-133a increase from 0.13 ppt (dry-air mole fraction in parts per trillion) in 2000 to 0.50 ppt in 2012-mid-2013 followed by an abrupt drop to ˜0.44 ppt by early 2015. Global emissions derived from these observations peaked at 3.1 kt in 2011, followed by a rapid decline of ˜0.5 kt yr-2 to reach 1.5 kt yr-1 in 2014. Sporadic HCFC-133a pollution events are detected in Europe from our high-resolution HCFC-133a records at three European stations, and in Asia from samples collected in Taiwan. European emissions are estimated to be <0.1 kt yr-1 although emission hot spots were identified in France.

  12. [Compositions of organic acids in PM10 emission sources in Xiamen urban atmosphere].

    PubMed

    Yang, Bing-Yu; Huang, Xing-Xing; Zheng, An; Liu, Bi-Lian; Wu, Shui-Ping

    2013-01-01

    The possible organic acid emission sources in PM10 in Xiamen urban atmosphere such as cooking, biomass burning, vehicle exhaust and soil/dust were obtained using a re-suspension test chamber. A total of 15 organic acids including dicarboxylic acids, fatty acids and aromatic acids were determined using GC/MS after derivatization with BF3/n-butanol. The results showed that the highest total concentration of 15 organic acids (53%) was found in cooking emission and the average concentration of the sum of linoleic acid and oleic acid was 24% +/- 14%. However, oxalic acid was the most abundant species followed by phthalic acid in gasoline vehicle exhaust. The ratios of adipic to azelaic acid in gasoline combustion emissions were significantly higher than those in other emission sources, which can be used to qualitatively differentiate anthropogenic and biological source of dicarboxylic acids in atmospheric samples. The ratios of malonic to succinic acid in source emissions (except gasoline generator emissions) were lower (0.07-0.44) than ambient PM10 samples (0.61-3.93), which can be used to qualitatively differentiate the primary source and the secondary source of dicarboxylic acids in urban PM10.

  13. The Role of Temporal Evolution in Modeling Atmospheric Emissions from Tropical Fires

    NASA Technical Reports Server (NTRS)

    Marlier, Miriam E.; Voulgarakis, Apostolos; Shindell, Drew T.; Faluvegi, Gregory S.; Henry, Candise L.; Randerson, James T.

    2014-01-01

    Fire emissions associated with tropical land use change and maintenance influence atmospheric composition, air quality, and climate. In this study, we explore the effects of representing fire emissions at daily versus monthly resolution in a global composition-climate model. We find that simulations of aerosols are impacted more by the temporal resolution of fire emissions than trace gases such as carbon monoxide or ozone. Daily-resolved datasets concentrate emissions from fire events over shorter time periods and allow them to more realistically interact with model meteorology, reducing how often emissions are concurrently released with precipitation events and in turn increasing peak aerosol concentrations. The magnitude of this effect varies across tropical ecosystem types, ranging from smaller changes in modeling the low intensity, frequent burning typical of savanna ecosystems to larger differences when modeling the short-term, intense fires that characterize deforestation events. The utility of modeling fire emissions at a daily resolution also depends on the application, such as modeling exceedances of particulate matter concentrations over air quality guidelines or simulating regional atmospheric heating patterns.

  14. On the emission of amines from terrestrial vegetation in the context of atmospheric new particle formation

    NASA Astrophysics Data System (ADS)

    Neftel, Albrecht; Sintermann, Jörg

    2015-04-01

    Airborne amines, specifically methylamines (MAs), play a key role in atmospheric new particle formation (NPF) by stabilising small molecule clusters. Agricultural emissions are assumed to constitute the most important MA source, but given the short atmospheric residence time of MAs, they can hardly have a direct impact on NFP events observed in remote regions. High MA contents as well as emissions by plants have already been described in the 19th century. Strong MA emissions predominantly occur during flowering as part of a pollination strategy. The behaviour is species specific, but examples of such species are common and widespread. In addition, vegetative plant tissue exhibiting high amounts of MAs might potentially lead to significant emissions, and the decomposition of organic material could constitute another source for airborne MAs. These mechanisms would provide sources, which could be crucial for the amine's role in NPF, especially in remote regions. Knowledge about vegetation-related amine emissions is, however, very limited and thus it is also an open question how Global Change and the intensified cycling of reactive nitrogen over the last 200 years have altered amine emissions from vegetation with a corresponding effect on NPF.

  15. Temporal Trend and Spatial Distribution of Speciated Atmospheric Mercury Emissions in China During 1978-2014.

    PubMed

    Wu, Qingru; Wang, Shuxiao; Li, Guoliang; Liang, Sai; Lin, Che-Jen; Wang, Yafei; Cai, Siyi; Liu, Kaiyun; Hao, Jiming

    2016-12-20

    Mercury pollution control has become a global goal. The accurate estimate of long-term mercury emissions in China is critical to evaluate the global mercury budget and the emission reduction potentials. In this study, we used a technology-based approach to compile a consistent series of China's atmospheric mercury emissions at provincial level from 1978 to 2014. China totally emitted 13 294 t of anthropogenic mercury to air during 1978-2014, in which gaseous elemental mercury, gaseous oxidized mercury, and particulate-bound mercury accounted for 58.2%, 37.1%, and 4.7%, respectively. The mercury removed during this period were 2085 t in coal-fired power plants (counting 49% of mercury input), 7259 t in Zn smelting (79%), 771 t in coal-fired industrial boilers (25%), and 658 t in cement production plants (27%), respectively. Annual mercury emissions increased from 147 t in 1978 to 530 t in 2014. Both sectoral and spatial emissions of atmospheric mercury experienced significant changes. The largest mercury emission source evolved from coal-fired industrial boilers before 1998, to zinc smelting during 1999-2004, coal-fired power plants during 2005-2008, finally to cement production after 2009. Coal-fired industrial boilers and cement production have become critical hotpots for China's mercury pollution control.

  16. Verification of greenhouse gas emission reductions: the prospect of atmospheric monitoring in polluted areas.

    PubMed

    Levin, Ingeborg; Hammer, Samuel; Eichelmann, Elke; Vogel, Felix R

    2011-05-28

    Independent verification of greenhouse gas emissions reporting is a legal requirement of the Kyoto Protocol, which has not yet been fully accomplished. Here, we show that dedicated long-term atmospheric measurements of greenhouse gases, such as carbon dioxide (CO(2)) and methane (CH(4)), continuously conducted at polluted sites can provide the necessary tool for this undertaking. From our measurements at the semi-polluted Heidelberg site in the upper Rhine Valley, we find that in the catchment area CH(4) emissions decreased on average by 32±6% from the second half of the 1990s until the first half of the 2000s, but the observed long-term trend of emissions is considerably smaller than that previously reported for southwest Germany. In contrast, regional fossil fuel CO(2) levels, estimated from high-precision (14)CO(2) observations, do not show any significant decreasing trend since 1986, in agreement with the reported emissions for this region. In order to provide accurate verification, these regional measurements would best be accompanied by adequate atmospheric transport modelling as required to precisely determine the relevant catchment area of the measurements. Furthermore, reliable reconciliation of reported emissions will only be possible if these are known at high spatial resolution in the catchment area of the observations. This information should principally be available in all countries that regularly report their greenhouse gas emissions to the United Nations Framework Convention on Climate Change. © 2011 The Royal Society

  17. Emission factor for atmospheric ammonia from a typical municipal wastewater treatment plant in South China.

    PubMed

    Zhang, Chunlin; Geng, Xuesong; Wang, Hao; Zhou, Lei; Wang, Boguang

    2017-01-01

    Atmospheric ammonia (NH3), a common alkaline gas found in air, plays a significant role in atmospheric chemistry, such as in the formation of secondary particles. However, large uncertainties remain in the estimation of ammonia emissions from nonagricultural sources, such as wastewater treatment plants (WWTPs). In this study, the ammonia emission factors from a large WWTP utilizing three typical biological treatment techniques to process wastewater in South China were calculated using the US EPA's WATER9 model with three years of raw sewage measurements and information about the facility. The individual emission factors calculated were 0.15 ± 0.03, 0.24 ± 0.05, 0.29 ± 0.06, and 0.25 ± 0.05 g NH3 m(-3) sewage for the adsorption-biodegradation activated sludge treatment process, the UNITANK process (an upgrade of the sequencing batch reactor activated sludge treatment process), and two slightly different anaerobic-anoxic-oxic treatment processes, respectively. The overall emission factor of the WWTP was 0.24 ± 0.06 g NH3m(-3) sewage. The pH of the wastewater influent is likely an important factor affecting ammonia emissions, because higher emission factors existed at higher pH values. Based on the ammonia emission factor generated in this study, sewage treatment accounted for approximately 4% of the ammonia emissions for the urban area of South China's Pearl River Delta (PRD) in 2006, which is much less than the value of 34% estimated in previous studies. To reduce the large uncertainty in the estimation of ammonia emissions in China, more field measurements are required. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Impact of Aquatic and Terrestrial Emissions on Atmospheric N2O Variability

    NASA Astrophysics Data System (ADS)

    Nevison, C. D.; Riddick, S. N.; Saikawa, E.; Hess, P. G.

    2013-12-01

    Atmospheric concentrations of the greenhouse gas nitrous oxide (N2O) have increased by about 20% since the preindustrial era, an increase that has been driven largely by use of anthropogenic nitrogen fertilizers. The N2O source associated with agriculture was historically underestimated by assessments that considered only direct emissions from fertilized fields, but more recently it has been recognized that 'indirect' emissions associated with N leaching and runoff to rivers and may account for as much as half of total agricultural N2O emissions. Meanwhile, recent regional atmospheric N2O inversions have inferred large North American agricultural N2O sources that are difficult to reconcile with global budget constraints. At the same time, it is not clear whether the inversions can detect indirect N2O emissions associated with nitrogen leaching and runoff. Here, we will present forward model simulations aimed at quantifying the relative magnitude, spatial distribution and timing of direct and indirect agricultural N2O emissions. The model simulations will be based on the Community Land Model (CLM), with new agricultural and trace N gas parameterizations, coupled to the River Transport Model (RTM), with a module for estimating river N transport and N2O production associated with in-stream sediment denitrification. The coupled CLM-RTM N2O fluxes will be used to force atmospheric chemistry tracer transport model (ACTM) simulations, with direct and indirect emissions carried as separate tracers. The ACTM results will be used to evaluate the impact of both types of emissions on site-specific variability in atmospheric N2O at United States monitoring sites and to assess the likelihood that current atmospheric monitoring networks can detect these signals. Locations of selected NOAA monitoring sites for atmospheric N2O over the continental United States, showing both aircraft (triangles) and surface flask or tower sites (filled circles). Site locations are superimposed on a

  19. A Pilot Study to Evaluate California's Fossil Fuel CO2 Emissions Using Atmospheric Observations

    NASA Astrophysics Data System (ADS)

    Graven, H. D.; Fischer, M. L.; Lueker, T.; Guilderson, T.; Brophy, K. J.; Keeling, R. F.; Arnold, T.; Bambha, R.; Callahan, W.; Campbell, J. E.; Cui, X.; Frankenberg, C.; Hsu, Y.; Iraci, L. T.; Jeong, S.; Kim, J.; LaFranchi, B. W.; Lehman, S.; Manning, A.; Michelsen, H. A.; Miller, J. B.; Newman, S.; Paplawsky, B.; Parazoo, N.; Sloop, C.; Walker, S.; Whelan, M.; Wunch, D.

    2016-12-01

    Atmospheric CO2 concentration is influenced by human activities and by natural exchanges. Studies of CO2 fluxes using atmospheric CO2 measurements typically focus on natural exchanges and assume that CO2 emissions by fossil fuel combustion and cement production are well-known from inventory estimates. However, atmospheric observation-based or "top-down" studies could potentially provide independent methods for evaluating fossil fuel CO2 emissions, in support of policies to reduce greenhouse gas emissions and mitigate climate change. Observation-based estimates of fossil fuel-derived CO2 may also improve estimates of biospheric CO2 exchange, which could help to characterize carbon storage and climate change mitigation by terrestrial ecosystems. We have been developing a top-down framework for estimating fossil fuel CO2 emissions in California that uses atmospheric observations and modeling. California is implementing the "Global Warming Solutions Act of 2006" to reduce total greenhouse gas emissions to 1990 levels by 2020, and it has a diverse array of ecosystems that may serve as CO2 sources or sinks. We performed three month-long field campaigns in different seasons in 2014-15 to collect flask samples from a state-wide network of 10 towers. Using measurements of radiocarbon in CO2, we estimate the fossil fuel-derived CO2 present in the flask samples, relative to marine background air observed at coastal sites. Radiocarbon (14C) is not present in fossil fuel-derived CO2 because of radioactive decay over millions of years, so fossil fuel emissions cause a measurable decrease in the 14C/C ratio in atmospheric CO2. We compare the observations of fossil fuel-derived CO2 to simulations based on atmospheric modeling and published fossil fuel flux estimates, and adjust the fossil fuel flux estimates in a statistical inversion that takes account of several uncertainties. We will present the results of the top-down technique to estimate fossil fuel emissions for our field

  20. Evaluating the impact of future emissions and climate on global atmospheric PAH transport

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    We use the 3D atmospheric chemical transport model GEOS-Chem to assess the relative impacts of changing anthropogenic emissions and climate on long-range polycyclic aromatic hydrocarbon (PAH) transport. Unlike most persistent organic pollutants (POPs), PAHs are emitted unintentionally from the incomplete combustion of organic material, and their release to the atmosphere is ongoing. In the Arctic, PAHs have been termed "emerging contaminants" because marine invertebrate concentrations are increasing while other POP concentrations are declining. We assess the influence of global anthropogenic emissions changes and climate change on the transport of phenanthrene (PHE), pyrene (PYR), and benzo[a]pyrene (BaP) to the Arctic, focusing on categorizing the relative importance of these global changes. We conduct simulations with GEOS-Chem varying emissions and climate respectively. We estimate future PAH emissions for important source regions based on projected changes in gross domestic product, demand for traditional fuel sources, energy consumption in the iron and steel production sector, and vehicle use. We also assess potential Arctic emission increases from greater oil/gas exploration and shipping activity due to reductions in sea ice. Climate variables assessed include higher global mean temperatures, shifts in atmospheric circulation patterns and precipitation, and changes in natural PAH emissions from wildfires. We find that climate changes will reduce transport of primary emitted BaP via increases in wet deposition of the particle phase, but will have less impact on PHE and PYR. Emissions reductions in developed regions will likely have a greater impact in the Arctic compared to increases in developing regions because of their spatial proximity.

  1. Atmospheric Ammonia Over China: Emission Estimates And Impact On Air Quality

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Chen, Y.; Zhao, Y.; Henze, D. K.

    2016-12-01

    Ammonia (NH3) in the atmosphere is an important precursor of aerosols, and its deposition through wet and dry processes can cause adverse effects on ecosystems. The ammonia emissions over China are particularly large due to intensive agricultural activities, yet our current estimates of Chinese ammonia emissions and associated consequences on air quality are subject to large errors. We use the GEOS-Chem chemical transport model and its adjoint model to better quantify this issue. The TES satellite observations of ammonia concentrations and surface measurements of wet deposition fluxes are assimilated into the model to constrain the ammonia emissions over China. Optimized emissions show a strong seasonal variability with emissions in summer a factor of 3 higher than winter. This is consistent with an improved bottom-up estimate of Chinese ammonia emissions from fertilizer use by using more practical fertilizer application rates for different crop types. We further use the GEOS-Chem adjoint at 0.25x0.3125 degree resolution to examine the sources contributing to the PM2.5 air pollution over North China. We show that wintertime PM2.5 over Beijing is largely contributed by residential and industrial sources, and ammonia emissions from agriculture activities. PM2.5 concentrations over North China are particularly sensitive to emissions of ammonia and nitrogen oxides, reflecting strong formation of aerosol nitrate in the cold seasons.

  2. Global mercury emissions to the atmosphere from anthropogenic and natural sources

    NASA Astrophysics Data System (ADS)

    Pirrone, N.; Cinnirella, S.; Feng, X.; Finkelman, R. B.; Friedli, H. R.; Leaner, J.; Mason, R.; Mukherjee, A. B.; Stracher, G. B.; Streets, D. G.; Telmer, K.

    2010-07-01

    This paper provides an up-to-date assessment of global mercury emissions from anthropogenic and natural sources. On an annual basis, natural sources account for 5207 Mg of mercury released to the global atmosphere, including the contribution from re-emission processes, which are emissions of previously deposited mercury originating from anthropogenic and natural sources, and primary emissions from natural reservoirs. Anthropogenic sources, which include a large number of industrial point sources, are estimated to account for 2320 Mg of mercury emitted annually. The major contributions are from fossil-fuel fired power plants (810 Mg yr-1), artisanal small scale gold mining (400 Mg yr-1), non-ferrous metals manufacturing (310 Mg yr-1), cement production (236 Mg yr-1), waste disposal (187 Mg yr-1) and caustic soda production (163 Mg yr-1). Therefore, our current estimate of global mercury emissions suggests that the overall contribution from natural sources (primary emissions + re-emissions) and anthropogenic sources is nearly 7527 Mg per year, the uncertainty associated with these estimates are related to the typology of emission sources and source regions.

  3. Global mercury emissions to the atmosphere from anthropogenic and natural sources

    NASA Astrophysics Data System (ADS)

    Pirrone, N.; Cinnirella, S.; Feng, X.; Finkelman, R. B.; Friedli, H. R.; Leaner, J.; Mason, R.; Mukherjee, A. B.; Stracher, G. B.; Streets, D. G.; Telmer, K.

    2010-02-01

    This paper provides an up-to-date assessment of global mercury emissions from anthropogenic and natural sources. On an annual basis, natural sources account for 5207 Mg of mercury released to the global atmosphere, including the contribution from re-emission processes, which are emissions of previously deposited mercury originating from anthropogenic and natural sources, and primary emissions from natural reservoirs. Anthropogenic sources, which include a large number of industrial point sources, are estimated to account for 2320 Mg of mercury emitted annually. The major contributions are from fossil-fuel fired power plants (810 Mg yr-1), artisanal small scale gold mining (400 Mg yr-1), non-ferrous metals manufacturing (310 Mg yr-1), cement production (236 Mg yr-1), waste disposal (187 Mg yr-1) and caustic soda production (163 Mg yr-1). Therefore, our current estimate of global mercury emissions suggests that the overall contribution from natural sources (primary emissions+re-emissions) and anthropogenic sources is nearly 7527 Mg per year, the uncertainty associated with these estimates are related to the typology of emission sources and source regions.

  4. An approach for verifying biogenic greenhouse gas emissions inventories with atmospheric CO 2 concentration data

    SciTech Connect

    Ogle, Stephen; Davis, Kenneth J.; Lauvaux, Thomas; Schuh, Andrew E.; Cooley, Dan; West, Tristram O.; Heath, L.; Miles, Natasha; Richardson, S. J.; Breidt, F. Jay; Smith, Jim; McCarty, Jessica L.; Gurney, Kevin R.; Tans, P. P.; Denning, Scott

    2015-03-10

    Verifying national greenhouse gas (GHG) emissions inventories is a critical step to ensure that reported emissions data to the United Nations Framework Convention on Climate Change (UNFCCC) are accurate and representative of a country’s contribution to GHG concentrations in the atmosphere. Verification could include a variety of evidence, but arguably the most convincing verification would be confirmation of a change in GHG concentrations in the atmosphere that is consistent with reported emissions to the UNFCCC. We report here on a case study evaluating this option based on a prototype atmospheric CO2 measurement network deployed in the Mid-Continent Region of the conterminous United States. We found that the atmospheric CO2 measurement data did verify the accuracy of the emissions inventory within the confidence limits of the emissions estimates, suggesting that this technology could be further developed and deployed more widely in the future for verifying reported emissions.

  5. TOWARD THE FORMATION OF CARBONACEOUS REFRACTORY MATTER IN HIGH TEMPERATURE HYDROCARBON-RICH ATMOSPHERES OF EXOPLANETS UPON MICROMETEOROID IMPACT

    SciTech Connect

    Dangi, Beni B.; Kim, Yong S.; Krasnokutski, Serge A.; Kaiser, Ralf I.; Bauschlicher Jr, Charles W.

    2015-05-20

    We report on laboratory simulation experiments mimicking the chemical processing of model atmospheres of exoplanets containing C3 and C4 hydrocarbons at moderate temperatures of 400 K upon interaction of catalytic surfaces of micrometeoroids. By utilizing an ultrasonic levitator device and heating singly levitated particles under simulated microgravity conditions, Raman spectroscopy is utilized as a non-invasive tool to probe on line and in situ the conversion of C3 and C4 hydrocarbons to refractory carbonaceous matter on the surfaces of levitated particles. Secondary Ion Mass Spectrometry and electron microscopic imaging were also conducted to gain further insight into the elementary composition and structures of the refractories formed. Our results provide compelling evidence that in the presence of a catalytic surface, which can be supplied in the form of micrometeoroids and atmospheric dust particles, hydrocarbon gases present in the atmospheres of exoplanets can be converted to refractory, carbon-rich carbonaceous matter of mainly graphitic structure with a carbon content of at least 90% at elevated temperatures. This finding might explain the low methane to carbon monoxide (CH{sub 4}–CO) ratio in the hot Neptune GJ 436b, where the abundant methane photochemically converts to higher order hydrocarbons and ultimately to refractory graphite-like carbon in the presence of a silicon surface.

  6. Hypothesized link between Neoproterozoic greening of the land surface and the establishment of an oxygen-rich atmosphere

    PubMed Central

    Kump, Lee R.

    2014-01-01

    Considerable geological, geochemical, paleontological, and isotopic evidence exists to support the hypothesis that the atmospheric oxygen level rose from an Archean baseline of essentially zero to modern values in two steps roughly 2.3 billion and 0.8–0.6 billion years ago (Ga). The first step in oxygen content, the Great Oxidation Event, was likely a threshold response to diminishing reductant input from Earth’s interior. Here I provide an alternative to previous suggestions that the second step was the result of the establishment of the first terrestrial fungal–lichen ecosystems. The consumption of oxygen by aerobes respiring this new source of organic matter in soils would have necessitated an increase in the atmospheric oxygen content to compensate for the reduced delivery of oxygen to the weathering environment below the organic-rich upper soil layer. Support for this hypothesis comes from the observed spread toward more negative carbon isotope compositions in Neoproterozoic (1.0–0.542 Ga) and younger limestones altered under the influence of ground waters, and the positive correlation between the carbon isotope composition and oxygen content of modern ground waters in contact with limestones. Thus, the greening of the planet’s land surfaces forced the atmospheric oxygen level to a new, higher equilibrium state. PMID:25225378

  7. Toward the Formation of Carbonaceous Refractory Matter in High Temperature Hydrocarbon-rich Atmospheres of Exoplanets Upon Micrometeoroid Impact

    NASA Astrophysics Data System (ADS)

    Dangi, Beni B.; Kim, Yong S.; Krasnokutski, Serge A.; Kaiser, Ralf I.; Bauschlicher, Charles W., Jr.

    2015-05-01

    We report on laboratory simulation experiments mimicking the chemical processing of model atmospheres of exoplanets containing C3 and C4 hydrocarbons at moderate temperatures of 400 K upon interaction of catalytic surfaces of micrometeoroids. By utilizing an ultrasonic levitator device and heating singly levitated particles under simulated microgravity conditions, Raman spectroscopy is utilized as a non-invasive tool to probe on line and in situ the conversion of C3 and C4 hydrocarbons to refractory carbonaceous matter on the surfaces of levitated particles. Secondary Ion Mass Spectrometry and electron microscopic imaging were also conducted to gain further insight into the elementary composition and structures of the refractories formed. Our results provide compelling evidence that in the presence of a catalytic surface, which can be supplied in the form of micrometeoroids and atmospheric dust particles, hydrocarbon gases present in the atmospheres of exoplanets can be converted to refractory, carbon-rich carbonaceous matter of mainly graphitic structure with a carbon content of at least 90% at elevated temperatures. This finding might explain the low methane to carbon monoxide (CH4-CO) ratio in the hot Neptune GJ 436b, where the abundant methane photochemically converts to higher order hydrocarbons and ultimately to refractory graphite-like carbon in the presence of a silicon surface.

  8. Emissions from pre-Hispanic metallurgy in the South American atmosphere.

    PubMed

    De Vleeschouwer, François; Vanneste, Heleen; Mauquoy, Dmitri; Piotrowska, Natalia; Torrejón, Fernando; Roland, Thomas; Stein, Ariel; Le Roux, Gaël

    2014-01-01

    Metallurgical activities have been undertaken in northern South America (NSA) for millennia. However, it is still unknown how far atmospheric emissions from these activities have been transported. Since the timing of metallurgical activities is currently estimated from scarce archaeological discoveries, the availability of reliable and continuous records to refine the timing of past metal deposition in South America is essential, as it provides an alternative to discontinuous archives, as well as evidence for global trace metal transport. We show in a peat record from Tierra del Fuego that anthropogenic metals likely have been emitted into the atmosphere and transported from NSA to southern South America (SSA) over the last 4200 yrs. These findings are supported by modern time back-trajectories from NSA to SSA. We further show that apparent anthropogenic Cu and Sb emissions predate any archaeological evidence for metallurgical activities. Lead and Sn were also emitted into the atmosphere as by-products of Inca and Spanish metallurgy, whereas local coal-gold rushes and the industrial revolution contributed to local contamination. We suggest that the onset of pre-Hispanic metallurgical activities is earlier than previously reported from archaeological records and that atmospheric emissions of metals were transported from NSA to SSA.

  9. Atmospheric mercury emissions and speciation at the sulphur bank mercury mine superfund site, Northern California.

    PubMed

    Nacht, David M; Gustin, Mae Sexauer; Engle, Mark A; Zehner, Richard E; Giglini, Anthony D

    2004-04-01

    One pathway for release of mercury (Hg) from naturally enriched sites is emission to the atmosphere. Elemental Hg, when emitted, will enter the global atmospheric pool. In contrast, if reactive gaseous Hg or Hg2+ (as HgCl2, HgBr2, or HgOH2) is formed, it will most likely be deposited locally. This study focused on the measurement of elemental Hg flux and reactive gaseous Hg concentrations at the Sulphur Bank Superfund Site, an area of natural Hg enrichment with anthropogenic disturbance and ongoing geothermal activity. Mean Hg emissions ranged from 14 to 11000 ng m(-2) h(-1), with the highest emissions from anthropogenically disturbed materials. Reactive gaseous Hg concentrations were the highest ever reported for a natural setting (0.3-76 ng m(-3)). Measured Hg fluxes were used within a Geographic Information System to estimate mercury releases to the atmosphere from the site. Results indicated approximately 17 kg of Hg y(-1) of is emitted to the atmosphere from the 3.8 km2 area, with half from mine waste, ore, and tailing piles and half from relatively undisturbed naturally enriched substrate.

  10. Simultaneous measurements of atmospheric emissions at 10, 33 and 90 GHz

    SciTech Connect

    Costales, J.B.

    1984-11-01

    As part of a larger experiment to measure the cosmic microwave background radiation spectrum, frequent simultaneous measurements of the microwave thermal emission from the earth's atmosphere were made at three fixed frequencies, namely, 10 GHz, 33 GHz and 90 GHz. We performed these measurements at two separate locations, Berkeley and White Mountain, which greatly differed in altitude and climatic conditions. Typical values measured in Berkeley of the atmospheric antenna temperature during good weather are 3.13 +- 0.30/sup 0/K, 12.3 +- 0.3/sup 0/K and 34.6 +- 0.5/sup 0/K, for 10, 33, and 90 GHz respectively. Corresponding values measured at White Mountain are 1.15 +- 0.1/sup 0/K, 4.51 +- 0.18/sup 0/K and 11.0 +- 0.2/sup 0/K. Because the measurements are simultaneous in nature, correlations between the measurements taken at the various frequencies provide constraints on models of the microwave emission of the earth's atmosphere, especially models describing atmospheric emission as a function of precipitable water content.

  11. Emissions from Pre-Hispanic Metallurgy in the South American Atmosphere

    PubMed Central

    De Vleeschouwer, François; Vanneste, Heleen; Mauquoy, Dmitri; Piotrowska, Natalia; Torrejón, Fernando; Roland, Thomas; Stein, Ariel; Le Roux, Gaël

    2014-01-01

    Metallurgical activities have been undertaken in northern South America (NSA) for millennia. However, it is still unknown how far atmospheric emissions from these activities have been transported. Since the timing of metallurgical activities is currently estimated from scarce archaeological discoveries, the availability of reliable and continuous records to refine the timing of past metal deposition in South America is essential, as it provides an alternative to discontinuous archives, as well as evidence for global trace metal transport. We show in a peat record from Tierra del Fuego that anthropogenic metals likely have been emitted into the atmosphere and transported from NSA to southern South America (SSA) over the last 4200 yrs. These findings are supported by modern time back-trajectories from NSA to SSA. We further show that apparent anthropogenic Cu and Sb emissions predate any archaeological evidence for metallurgical activities. Lead and Sn were also emitted into the atmosphere as by-products of Inca and Spanish metallurgy, whereas local coal-gold rushes and the industrial revolution contributed to local contamination. We suggest that the onset of pre-Hispanic metallurgical activities is earlier than previously reported from archaeological records and that atmospheric emissions of metals were transported from NSA to SSA. PMID:25353346

  12. Decadal Trends in Global CO Emissions as Inferred from Atmospheric Inversion

    NASA Astrophysics Data System (ADS)

    Yin, Y.; Chevallier, F.; Ciais, P.; Broquet, G.; Cheiney, A. F.; Pison, I.; Saunois, M.

    2015-12-01

    Large negative trends of atmospheric CO concentrations in the recent decade are observed by both surface measurements and satellite retrievals over many regions globally. However, this decrease in CO concentration cannot be fully explained by current emission inventories. Here, we aim at attributing the observed CO concentration decline using an atmospheric inversion that simultaneously optimizes CO sources (from surface emissions and atmospheric oxidations of hydrocarbons) and CO sinks (through reaction with oxidant hydroxyl radical OH in the atmosphere) with observational constraints of CO and other chemically related trace gases. Satellite retrievals of CO total column from the latest product v6 of MOPITT sensor together with surface in-situ measurements of methane and methyl chloroform are assimilated for the period from 2002 to 2011. The optimized concentrations are evaluated with independent observations. Sensitivity tests of ACTM latitudinal/vertical resolution, prior OH fields, and additional observational constraints are discussed. The optimized CO budgets indicate that the CO concentration decline is primarily caused by a decrease in the CO emissions by 3% yr-1, whereas no significant trends are found at the global scale for the chemical CO sources and for the OH concentrations that regulate CO sinks. We highlighted some regional inconsistencies between bottom-up and top-down results. In contrast to bottom-up inventories, the inversion finds negative trends over China and positive trends over Africa.

  13. Will atmospheric CO2 concentration continue to increase if anthropogenic CO2 emissions cease?

    NASA Astrophysics Data System (ADS)

    MacDougall, A. H.; Eby, M.; Weaver, A. J.

    2013-12-01

    If anthropogenic CO2 emissions were to suddenly cease, the evolution of the atmospheric CO2 concentration would depend on the magnitude and sign of natural carbon sources and sinks. Experiments using Earth system models indicate that overall carbon sinks would dominate. However, these models have typically neglected the permafrost carbon pool, which has the potential to introduce an additional terrestrial source of carbon to the atmosphere. Here we use the University of Victoria Earth System Climate Model, which has recently been expanded to include permafrost carbon stocks and exchanges with the atmosphere. In a scenario of zeroed CO2 and sulphate aerosol emissions, we assess whether the warming induced by specified constant concentrations of non-CO2 greenhouse gases could slow the CO2 decline following zero emissions, or even reverse this trend and cause CO2 to increase over time. We find that a radiative forcing from non-CO2 gases of approximately 0.6 W m-2 results in a near balance of CO2 emissions from the terrestrial biosphere and uptake of CO2 by the oceans, resulting in near-constant atmospheric CO2 concentrations for at least a century after emissions are eliminated. At higher values of non-CO2 radiative forcing, CO2 concentrations increase over time, regardless of when emissions cease during the 21st century. Given that the present-day radiative forcing from non-CO2 greenhouse gases is about 0.95 W m-2, our results suggest that if we were to eliminate all CO2 and aerosols emissions without also decreasing non-CO2 greenhouse gas emissions, CO2 levels would increase over time, resulting in a small increase in climate warming. The sudden and total cessation of anthropogenic CO2 emissions is an unlikely future scenario. However, such cessation experiments provide a useful method for evaluating the relative strength of the terrestrial and oceanic carbon cycle feedbacks in the presence of forcing from non-CO2 greenhouse gasses.

  14. Gridded anthropogenic emissions inventory and atmospheric transport of carbonyl sulfide in the U.S.

    NASA Astrophysics Data System (ADS)

    Zumkehr, Andrew; Hilton, Timothy W.; Whelan, Mary; Smith, Steve; Campbell, J. Elliott

    2017-02-01

    Carbonyl sulfide (COS or OCS), the most abundant sulfur-containing gas in the troposphere, has recently emerged as a potentially important atmospheric tracer for the carbon cycle. Atmospheric inverse modeling studies may be able to use existing tower, airborne, and satellite observations of COS to infer information about photosynthesis. However, such analysis relies on gridded anthropogenic COS source estimates that are largely based on industry activity data from over three decades ago. Here we use updated emission factor data and industry activity data to develop a gridded inventory with a 0.1° resolution for the U.S. domain. The inventory includes the primary anthropogenic COS sources including direct emissions from the coal and aluminum industries as well as indirect sources from industrial carbon disulfide emissions. Compared to the previously published inventory, we found that the total anthropogenic source (direct and indirect) is 47% smaller. Using this new gridded inventory to drive the Sulfur Transport and Deposition Model/Weather Research and Forecasting atmospheric transport model, we found that the anthropogenic contribution to COS variation in the troposphere is small relative to the biosphere influence, which is encouraging for carbon cycle applications in this region. Additional anthropogenic sectors with highly uncertain emission factors require further field measurements.

  15. Increased soil emissions of potent greenhouse gases under increased atmospheric CO2.

    PubMed

    van Groenigen, Kees Jan; Osenberg, Craig W; Hungate, Bruce A

    2011-07-13

    Increasing concentrations of atmospheric carbon dioxide (CO(2)) can affect biotic and abiotic conditions in soil, such as microbial activity and water content. In turn, these changes might be expected to alter the production and consumption of the important greenhouse gases nitrous oxide (N(2)O) and methane (CH(4)) (refs 2, 3). However, studies on fluxes of N(2)O and CH(4) from soil under increased atmospheric CO(2) have not been quantitatively synthesized. Here we show, using meta-analysis, that increased CO(2) (ranging from 463 to 780 parts per million by volume) stimulates both N(2)O emissions from upland soils and CH(4) emissions from rice paddies and natural wetlands. Because enhanced greenhouse-gas emissions add to the radiative forcing of terrestrial ecosystems, these emissions are expected to negate at least 16.6 per cent of the climate change mitigation potential previously predicted from an increase in the terrestrial carbon sink under increased atmospheric CO(2) concentrations. Our results therefore suggest that the capacity of land ecosystems to slow climate warming has been overestimated. ©2011 Macmillan Publishers Limited. All rights reserved

  16. Carbon isotopic signature of coal-derived methane emissions to the atmosphere: from coalification to alteration

    NASA Astrophysics Data System (ADS)

    Zazzeri, Giulia; Lowry, Dave; Fisher, Rebecca E.; France, James L.; Lanoisellé, Mathias; Kelly, Bryce F. J.; Necki, Jaroslaw M.; Iverach, Charlotte P.; Ginty, Elisa; Zimnoch, Miroslaw; Jasek, Alina; Nisbet, Euan G.

    2016-11-01

    Currently, the atmospheric methane burden is rising rapidly, but the extent to which shifts in coal production contribute to this rise is not known. Coalbed methane emissions into the atmosphere are poorly characterised, and this study provides representative δ13CCH4 signatures of methane emissions from specific coalfields. Integrated methane emissions from both underground and opencast coal mines in the UK, Australia and Poland were sampled and isotopically characterised. Progression in coal rank and secondary biogenic production of methane due to incursion of water are suggested as the processes affecting the isotopic composition of coal-derived methane. An averaged value of -65 ‰ has been assigned to bituminous coal exploited in open cast mines and of -55 ‰ in deep mines, whereas values of -40 and -30 ‰ can be allocated to anthracite opencast and deep mines respectively. However, the isotopic signatures that are included in global atmospheric modelling of coal emissions should be region- or nation-specific, as greater detail is needed, given the wide global variation in coal type.

  17. Transport and radiative impacts of atmospheric pollen using online, observation-based emissions

    NASA Astrophysics Data System (ADS)

    Wozniak, M. C.; Steiner, A. L.; Solmon, F.; Li, Y.

    2015-12-01

    Atmospheric pollen emitted from trees and grasses exhibits both a high temporal variability and a highly localized spatial distribution that has been difficult to quantify in the atmosphere. Pollen's radiative impact is also not quantified because it is neglected in climate modeling studies. Here we couple an online, meteorological active pollen emissions model guided by observations of airborne pollen to understand the role of pollen in the atmosphere. We use existing pollen counts from 2003-2008 across the continental U.S. in conjunction with a tree database and historical meteorological data to create an observation-based phenological model that produces accurately scaled and timed emissions. These emissions are emitted and transported within the regional climate model (RegCM4) and the direct radiative effect is calculated. Additionally, we simulate the rupture of coarse pollen grains into finer particles by adding a second size mode for pollen emissions, which contributes to the shortwave radiative forcing and also has an indirect effect on climate.

  18. [Investigation on the gas temperature of a plasma jet at atmospheric pressure by emission spectrum].

    PubMed

    Li, Xue-chen; Yuan, Ning; Jia, Peng-ying; Niu, Dong-ying

    2010-11-01

    A plasma jet of a dielectric barrier discharge in coaxial electrode was used to produce plasma plume in atmospheric pressure argon. Spatially and temporally resolved measurement was carried out by photomultiplier tubes. The light emission signals both from the dielectric barrier discharge and from the plasma plume were analyzed. Furthermore, emission spectrum from the plasma plume was collected by high-resolution optical spectrometer. The emission spectra of OH (A 2sigma + --> X2 II, 307.7-308.9 nm) and the first negative band of N2+ (B2 sigma u+ --> X2 IIg+, 390-391.6 nm) were used to estimate the rotational temperature of the plasma plume by fitting the experimental spectra to the simulated spectra. The rotational temperature obtained is about 443 K by fitting the emission spectrum from the OH, and that from the first negative band of N2+ is about 450 K. The rotational temperatures obtained by the two method are consistent within 5% error band. The gas temperature of the plasma plume at atmospheric pressure was obtained because rotational temperature equals to gas temperature approximately in gas discharge at atmospheric pressure. Results show that gas temperature increases with increasing the applied voltage.

  19. Global oceanic emission of ammonia: Constraints from seawater and atmospheric observations

    NASA Astrophysics Data System (ADS)

    Paulot, F.; Jacob, D. J.; Johnson, M. T.; Bell, T. G.; Baker, A. R.; Keene, W. C.; Lima, I. D.; Doney, S. C.; Stock, C. A.

    2015-08-01

    Current global inventories of ammonia emissions identify the ocean as the largest natural source. This source depends on seawater pH, temperature, and the concentration of total seawater ammonia (NHx(sw)), which reflects a balance between remineralization of organic matter, uptake by plankton, and nitrification. Here we compare [NHx(sw)] from two global ocean biogeochemical models (BEC and COBALT) against extensive ocean observations. Simulated [NHx(sw)] are generally biased high. Improved simulation can be achieved in COBALT by increasing the plankton affinity for NHx within observed ranges. The resulting global ocean emissions is 2.5 TgN a-1, much lower than current literature values (7-23 TgN a-1), including the widely used Global Emissions InitiAtive (GEIA) inventory (8 TgN a-1). Such a weak ocean source implies that continental sources contribute more than half of atmospheric NHx over most of the ocean in the Northern Hemisphere. Ammonia emitted from oceanic sources is insufficient to neutralize sulfate aerosol acidity, consistent with observations. There is evidence over the Equatorial Pacific for a missing source of atmospheric ammonia that could be due to photolysis of marine organic nitrogen at the ocean surface or in the atmosphere. Accommodating this possible missing source yields a global ocean emission of ammonia in the range 2-5 TgN a-1, comparable in magnitude to other natural sources from open fires and soils.

  20. Dark-to-arc transition in field emission dominated atmospheric microdischarges

    SciTech Connect

    Tholeti, Siva Sashank; Semnani, Abbas; Peroulis, Dimitrios; Alexeenko, Alina A.

    2015-08-15

    We study the voltage-current characteristics of gas discharges driven by field emission of electrons at the microscale. Particle-in-cell with Monte Carlo collision calculations are first verified by comparison with breakdown voltage measurements and then used to investigate atmospheric discharges in nitrogen at gaps from 1 to 10 μm. The results indicate the absence of the classical glow discharge regime because field electron emission replaces secondary electron emission as the discharge sustaining mechanism. Additionally, the onset of arcing is significantly delayed due to rarefied effects in electron transport. While field emission reduces the breakdown voltage, the power required to sustain an arc of the same density in microgaps is as much as 30% higher than at macroscale.

  1. Effect of laser intensity on radio frequency emissions from laser induced breakdown of atmospheric air

    SciTech Connect

    Vinoth Kumar, L.; Manikanta, E.; Leela, Ch.; Prem Kiran, P. E-mail: prem@uohyd.ac.in

    2016-06-07

    The studies on the effect of input laser intensity, through the variation of laser focusing geometry, on radio frequency (RF) emissions, over 30–1000 MHz from nanosecond (ns) and picosecond (ps) laser induced breakdown (LIB) of atmospheric air are presented. The RF emissions from the ns and ps LIB were observed to be decreasing and increasing, respectively, when traversed from tight to loose focusing conditions. The angular and radial intensities of the RF emissions from the ns and ps LIB are found to be consistent with sin{sup 2}θ/r{sup 2} dependence of the electric dipole radiation. The normalized RF emissions were observed to vary with incident laser intensity (Iλ{sup 2}), indicating the increase in the induced dipole moment at moderate input laser intensities and the damping of radiation due to higher recombination rate of plasma at higher input laser intensities.

  2. Atmospheric inversion for cost effective quantification of city CO2 emissions

    NASA Astrophysics Data System (ADS)

    Wu, L.; Broquet, G.; Ciais, P.; Bellassen, V.; Vogel, F.; Chevallier, F.; Xueref-Remy, I.; Wang, Y.

    2015-11-01

    Cities, currently covering only a very small portion (< 3 %) of the world's land surface, directly release to the atmosphere about 44 % of global energy-related CO2, and are associated with 71-76 % of CO2 emissions from global final energy use. Although many cities have set voluntary climate plans, their CO2 emissions are not evaluated by Monitoring, Reporting and Verification (MRV) procedures that play a key role for market- or policy-based mitigation actions. Here we propose a monitoring tool that could support the development of such procedures at the city scale. It is based on an atmospheric inversion method that exploits inventory data and continuous atmospheric CO2 concentration measurements from a network of stations within and around cities to estimate city CO2 emissions. We examine the cost-effectiveness and the performance of such a tool. The instruments presently used to measure CO2 concentrations at research stations are expensive. However, cheaper sensors are currently developed and should be useable for the monitoring of CO2 emissions from a megacity in the near-term. Our assessment of the inversion method is thus based on the use of several types of hypothetical networks, with a range of numbers of sensors sampling at 25 m a.g.l. The study case for this assessment is the monitoring of the emissions of the Paris metropolitan area (~ 12 million inhabitants and 11.4 Tg C emitted in 2010) during the month of January 2011. The performance of the inversion is evaluated in terms of uncertainties in the estimates of total and sectoral CO2 emissions. These uncertainties are compared to a notional ambitious target to diagnose annual total city emissions with an uncertainty of 5 % (2-sigma). We find that, with 10 stations only, which is the typical size of current pilot networks that are deployed in some cities, the uncertainty for the 1-month total city CO2 emissions is significantly reduced by the inversion by ~ 42 % but still corresponds to an annual

  3. Gliese 581d Habitable with a CO2-rich atmosphere: Results from Numerical Climate Simulations.

    NASA Astrophysics Data System (ADS)

    Wordsworth, Robin; Forget, F.; Selsis, F.; Madeleine, J. B.; Millour, E.; Eymet, V.

    2010-10-01

    The exoplanet Gl581d (discovered in 2007) is relatively low mass and near to the outer edge of its system's habitable zone, which has led to much speculation on its possible climate. To help understand the possible conditions on this planet, we have developed a new universal 3D global climate model (GCM). It is derived from the LMD GCMs already used to simulate the Earth, Mars and other terrestrial atmospheres in the solar system, and hence has already been validated over a wide range of physical conditions. We have performed a range of simulations to assess whether, given simple combinations of chemically stable gases (CO2, H2O and N2), Gl581d could sustain liquid water on its surface. Compared to a Sun-like star, the red dwarf Gliese 581 allows higher planetary temperatures, because Rayleigh scattering is reduced. Taking into account the scattering greenhouse effect of both CO2 and H2O clouds, we find that several tens of bars of CO2 are sufficient to maintain global mean temperatures above the melting point of water. As Gl581d is probably in a tidally resonant orbit, condensables such as water and CO2 may be trapped on its dark sides or poles. However, we find that even with conservative assumptions, redistribution of heat by the atmosphere is enough to allow stable conditions with surface liquid water. A dense atmosphere of this kind is quite possible for such a large planet, and could be distinguished from other cases using future observations.

  4. An attempt at estimating Paris area CO2 emissions from atmospheric concentration measurements

    NASA Astrophysics Data System (ADS)

    Bréon, F. M.; Broquet, G.; Puygrenier, V.; Chevallier, F.; Xueref-Rémy, I.; Ramonet, M.; Dieudonné, E.; Lopez, M.; Schmidt, M.; Perrussel, O.; Ciais, P.

    2014-04-01

    Atmospheric concentration measurements are used to adjust the daily to monthly budget of CO2 emissions from the AirParif inventory of the Paris agglomeration. We use 5 atmospheric monitoring sites including one at the top of the Eiffel tower. The atmospheric inversion is based on a Bayesian approach, and relies on an atmospheric transport model with a spatial resolution of 2 km with boundary conditions from a global coarse grid transport model. The inversion tool adjusts the CO2 fluxes (anthropogenic and biogenic) with a temporal resolution of 6 h, assuming temporal correlation of emissions uncertainties within the daily cycle and from day to day, while keeping the a priori spatial distribution from the emission inventory. The inversion significantly improves the agreement between measured and modelled concentrations. However, the amplitude of the atmospheric transport errors is often large compared to the CO2 gradients between the sites that are used to estimate the fluxes, in particular for the Eiffel tower station. In addition, we sometime observe large model-measurement differences upwind from the Paris agglomeration, which confirms the large and poorly constrained contribution from distant sources and sinks included in the prescribed CO2 boundary conditions These results suggest that (i) the Eiffel measurements at 300 m above ground cannot be used with the current system and (ii) the inversion shall rely on the measured upwind-downwind gradients rather than the raw mole fraction measurements. With such setup, realistic emissions are retrieved for two 30 day periods. Similar inversions over longer periods are necessary for a proper evaluation of the results.

  5. A comparative analysis of two highly spatially resolved European atmospheric emission inventories

    NASA Astrophysics Data System (ADS)

    Ferreira, J.; Guevara, M.; Baldasano, J. M.; Tchepel, O.; Schaap, M.; Miranda, A. I.; Borrego, C.

    2013-08-01

    A reliable emissions inventory is highly important for air quality modelling applications, especially at regional or local scales, which require high resolutions. Consequently, higher resolution emission inventories have been developed that are suitable for regional air quality modelling. This research performs an inter-comparative analysis of different spatial disaggregation methodologies of atmospheric emission inventories. This study is based on two different European emission inventories with different spatial resolutions: 1) the EMEP (European Monitoring and Evaluation Programme) inventory and 2) an emission inventory developed by the TNO (Netherlands Organisation for Applied Scientific Research). These two emission inventories were converted into three distinct gridded emission datasets as follows: (i) the EMEP emission inventory was disaggregated by area (EMEParea) and (ii) following a more complex methodology (HERMES-DIS - High-Elective Resolution Modelling Emissions System - DISaggregation module) to understand and evaluate the influence of different disaggregation methods; and (iii) the TNO gridded emissions, which are based on different emission data sources and different disaggregation methods. A predefined common grid with a spatial resolution of 12 × 12 km2 was used to compare the three datasets spatially. The inter-comparative analysis was performed by source sector (SNAP - Selected Nomenclature for Air Pollution) with emission totals for selected pollutants. It included the computation of difference maps (to focus on the spatial variability of emission differences) and a linear regression analysis to calculate the coefficients of determination and to quantitatively measure differences. From the spatial analysis, greater differences were found for residential/commercial combustion (SNAP02), solvent use (SNAP06) and road transport (SNAP07). These findings were related to the different spatial disaggregation that was conducted by the TNO and HERMES

  6. Atmospheric mercury emissions from waste combustions measured by continuous monitoring devices.

    PubMed

    Takahashi, Fumitake; Shimaoka, Takayuki; Kida, Akiko

    2012-06-01

    Atmospheric mercury emissions have attracted great attention owing to adverse impact of mercury on human health and the ecosystem. Although waste combustion is one of major anthropogenic sources, estimated emission might have large uncertainty due to great heterogeneity of wastes. This study investigated atmospheric emissions of speciated mercury from the combustions of municipal solid wastes (MSW), sewage treatment sludge (STS), STS with waste plastics, industrial waste mixtures (IWM), waste plastics from construction demolition, and woody wastes using continuous monitoring devices. Reactive gaseous mercury was the major form at the inlet side of air pollution control devices in all combustion cases. Its concentration was 2.0-70.6 times larger than elemental mercury concentration. In particular, MSW, STS, and IWM combustions emitted higher concentration of reactive gaseous mercury. Concentrations of both gaseous mercury species varied greatly for all waste combustions excluding woody waste. Variation coefficients of measured data were nearly equal to or more than 1.0. Emission factors of gaseous elemental mercury, reactive gaseous mercury, and total mercury were calculated using continuous monitoring data. Total mercury emission factors are 0.30 g-Hg/Mg for MSW combustion, 0.21 g-Hg/Mg for STS combustion, 0.077 g-Hg/Mg for STS with waste plastics, 0.724 g-Hg/Mg for industrial waste mixtures, 0.028 g-Hg/Mg for waste plastic combustion, and 0.0026 g-Hg/Mg for woody waste combustion. All emission factors evaluated in this study were comparable or lower than other reported data. Emission inventory using old emission factors likely causes an overestimation.

  7. Satellite observations of atmospheric methane and their value for quantifying methane emissions

    NASA Astrophysics Data System (ADS)

    Jacob, Daniel J.; Turner, Alexander J.; Maasakkers, Joannes D.; Sheng, Jianxiong; Sun, Kang; Liu, Xiong; Chance, Kelly; Aben, Ilse; McKeever, Jason; Frankenberg, Christian

    2016-11-01

    Methane is a greenhouse gas emitted by a range of natural and anthropogenic sources. Atmospheric methane has been measured continuously from space since 2003, and new instruments are planned for launch in the near future that will greatly expand the capabilities of space-based observations. We review the value of current, future, and proposed satellite observations to better quantify and understand methane emissions through inverse analyses, from the global scale down to the scale of point sources and in combination with suborbital (surface and aircraft) data. Current global observations from Greenhouse Gases Observing Satellite (GOSAT) are of high quality but have sparse spatial coverage. They can quantify methane emissions on a regional scale (100-1000 km) through multiyear averaging. The Tropospheric Monitoring Instrument (TROPOMI), to be launched in 2017, is expected to quantify daily emissions on the regional scale and will also effectively detect large point sources. A different observing strategy by GHGSat (launched in June 2016) is to target limited viewing domains with very fine pixel resolution in order to detect a wide range of methane point sources. Geostationary observation of methane, still in the proposal stage, will have the unique capability of mapping source regions with high resolution, detecting transient "super-emitter" point sources and resolving diurnal variation of emissions from sources such as wetlands and manure. Exploiting these rapidly expanding satellite measurement capabilities to quantify methane emissions requires a parallel effort to construct high-quality spatially and sectorally resolved emission inventories. Partnership between top-down inverse analyses of atmospheric data and bottom-up construction of emission inventories is crucial to better understanding methane emission processes and subsequently informing climate policy.

  8. Thermal Emission Spectrometer Results: Mars Atmospheric Thermal Structure and Aerosol Distribution

    NASA Technical Reports Server (NTRS)

    Smith, Michael D.; Pearl, John C.; Conrath, Barney J.; Christensen, Philip R.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Infrared spectra returned by the Thermal Emission Spectrometer (TES) are well suited for retrieval of the thermal structure and the distribution of aerosols in the Martian atmosphere. Combined nadir- and limb-viewing spectra allow global monitoring of the atmosphere up to 0.01 mbar (65 km). We report here on the atmospheric thermal structure and the distribution of aerosols as observed thus far during the mapping phase of the Mars Global Surveyor mission. Zonal and temporal mean cross sections are used to examine the seasonal evolution of atmospheric temperatures and zonal winds during a period extending from northern hemisphere mid-summer through vernal equinox (L(sub s) = 104-360 deg). Temperature maps at selected pressure levels provide a characterization of planetary-scale waves. Retrieved atmospheric infrared dust opacity maps show the formation and evolution of regional dust storms during southern hemisphere summer. Response of the atmospheric thermal structure to the changing dust loading is observed. Maps of water-ice clouds as viewed in the thermal infrared are presented along with seasonal trends of infrared water-ice opacity. Uses of these observations for diagnostic studies of the dynamics of the atmosphere are discussed.

  9. THEORETICAL EMISSION SPECTRA OF ATMOSPHERES OF HOT ROCKY SUPER-EARTHS

    SciTech Connect

    Ito, Yuichi; Ikoma, Masahiro; Kawahara, Hajime; Nagahara, Hiroko; Kawashima, Yui; Nakamoto, Taishi

    2015-03-10

    Motivated by recent detection of transiting high-density super-Earths, we explore the detectability of hot rocky super-Earths orbiting very close to their host stars. In an environment hot enough for their rocky surfaces to be molten, they would have an atmosphere composed of gas species from the magma oceans. In this study, we investigate the radiative properties of the atmosphere that is in gas/melt equilibrium with the underlying magma ocean. Our equilibrium calculations yield Na, K, Fe, Si, SiO, O, and O{sub 2} as the major atmospheric species. We compile the radiative absorption line data of those species available in the literature and calculate their absorption opacities in the wavelength region of 0.1–100 μm. Using them, we integrate the thermal structure of the atmosphere. Then, we find that thermal inversion occurs in the atmosphere because of the UV absorption by SiO. In addition, we calculate the ratio of the planetary to stellar emission fluxes during secondary eclipse, and we find prominent emission features induced by SiO at 4 μm detectable by Spitzer, and those at 10 and 100 μm detectable by near-future space telescopes.

  10. Two-dimensional radiative transfer for the retrieval of limb emission measurements in the martian atmosphere

    NASA Astrophysics Data System (ADS)

    Kleinböhl, Armin; Friedson, A. James; Schofield, John T.

    2017-01-01

    The remote sounding of infrared emission from planetary atmospheres using limb-viewing geometry is a powerful technique for deriving vertical profiles of structure and composition on a global scale. Compared with nadir viewing, limb geometry provides enhanced vertical resolution and greater sensitivity to atmospheric constituents. However, standard limb profile retrieval techniques assume spherical symmetry and are vulnerable to biases produced by horizontal gradients in atmospheric parameters. We present a scheme for the correction of horizontal gradients in profile retrievals from limb observations of the martian atmosphere. It characterizes horizontal gradients in temperature, pressure, and aerosol extinction along the line-of-sight of a limb view through neighboring measurements, and represents these gradients by means of two-dimensional radiative transfer in the forward model of the retrieval. The scheme is applied to limb emission measurements from the Mars Climate Sounder instrument on Mars Reconnaissance Orbiter. Retrieval simulations using data from numerical models indicate that biases of up to 10 K in the winter polar region, obtained with standard retrievals using spherical symmetry, are reduced to about 2 K in most locations by the retrieval with two-dimensional radiative transfer. Retrievals from Mars atmospheric measurements suggest that the two-dimensional radiative transfer greatly reduces biases in temperature and aerosol opacity caused by observational geometry, predominantly in the polar winter regions.

  11. Modeling Pluto's Ice-Rich Surface and Its Interaction with Atmosphere

    NASA Astrophysics Data System (ADS)

    Wei, Q.; Hu, Y.

    2016-12-01

    Recent discoveries made available through NASA's New Horizon mission revealed a new world on Pluto with a plateau of "young" surface, the Sputnik Planum. It is a gigantic reservoir of volatile ice on top of an impact basin. The reason of such a high level of concentration of volatile ice is yet unknown. We are actively looking into explanations through atmospheric models and ice sheet models. Apart from the quantity of ice on SP, its surface age constrained by impact flux models to under 10Myr is significantly different from other parts of Pluto. Convection of solid nitrogen ice has been proposed as a viable cause. We endeavor to explore other possibilities that may have jointly contributed to this phenomena, including atmospheric condensation, ice sheet evolution, etc. Unique rheological properties of nitrogen ice, which is thought to dominate the Sputnik Planum, may hold the key to answering our questions. They are soft and easy to deform under its own weight even at Pluto's surface temperature of around 40K. Based on our initial simulations with numerical ice sheet models, we propose that once a crater is created on the Sputnik Planum, deformation under internal stress kicks in as a primary mechanism to flatten out craters. This could be done in a time scale of 100,000 years, significantly shorter than the maximum surface age contrained by crater densitiess models. As the surface arpproaches a flat state, such mechanism becomes weaker. The surface feature is then dominated by convection.

  12. Atmosphere-derived National Emissions of Ozone Depleting Substances and Substitutes for the United States

    NASA Astrophysics Data System (ADS)

    Hu, L.; Montzka, S. A.; Miller, J. B.; Andrews, A. E.; Miller, B. R.; Lehman, S.; Godwin, D.; Thoning, K. W.; Sweeney, C.; Chen, H.; Fischer, M. L.; Biraud, S.; Torn, M. S.; Mountain, M. E.; Nehrkorn, T.; Eluszkiewicz, J.; Saikawa, E.; Hall, B. D.; Elkins, J. W.; Tans, P. P.

    2014-12-01

    Chlorofluorocarbons (CFCs), halons, carbon tetrachloride (CCl4), and methyl chloroform (CH3CCl3) are strong ozone-depleting substances (ODSs). Their production and consumption have been controlled by the Montreal Protocol since 1989 in developed countries and 1999 in developing countries. Although global atmospheric burdens of some of these gases have been declining for the last decade, their emissions continue due to releases from their existing reservoirs. Hydrochlorofluorocarbons (HCFCs) are transitional substitutes for CFCs; because they also deplete stratospheric ozone, they are also controlled by the Montreal Protocol. Hydrofluorocarbons (HFCs) are replacements for CFCs and HCFCs. Due to incomplete understanding of the reservoir size and emission rates for ODSs and their substitutes, uncertainty of their national emissions from inventory-based "bottom-up" estimates is undetermined. In this study, we use our atmospheric observations from multiple surface sites and aircraft profiles across the continental US from 2008 to 2012, along with data from remote sites over the Pacific basin, to derive national emissions of ODSs and their substitutes using inverse modeling. The performance of our modeling framework and the sensitivity of derived emissions to prior fluxes and model-data mismatch errors were investigated by conducting a suite of synthetic-data experiments. Sensitivity of derived fluxes to boundary values and transport was explored in real-data inversions. Our preliminary results suggest that (1) US emissions of HCFC-22 and HCFC-142b are currently declining at faster rates than those reported by US EPA; (2) our emission estimate of HFC-134a, the most abundant HFCs in the atmosphere, is consistent with the estimate reported by US EPA, whereas our estimates for some currently minor HFCs (i.e. HFC-125 and HFC-143a) show no significant emission trends during 2008 - 2012, which is inconsistent with a 70 - 120 % increase over this period reported by US EPA; and

  13. Atmospheric polycyclic aromatic hydrocarbons and isomer ratios as tracers of biomass burning emissions in Northern India.

    PubMed

    Rajput, Prashant; Sarin, M M; Sharma, Deepti; Singh, Darshan

    2014-04-01

    Emission from large-scale post-harvest agricultural-waste burning (paddy-residue burning during October-November and wheat-residue burning in April-May) is a conspicuous feature in northern India. The poor and open burning of agricultural residue result in massive emission of carbonaceous aerosols and organic pollutants to the atmosphere. In this context, concentrations of atmospheric polycyclic aromatic hydrocarbons (PAHs) and their isomer ratios have been studied for a 2-year period from a source region (Patiala: 30.2°N; 76.3°E) of two distinct biomass burning emissions. The concentrations of 4-6 ring PAHs are considerably higher compared to 2-3 ring PAHs in the ambient particulate matter (PM2.5). The crossplots of PAH isomer ratios, fluoranthene / (fluoranthene + pyrene) and indeno[1,2,3-cd]pyrene/(indeno[1,2,3-cd]pyrene + benzo[g,h,i]perylene) for two biomass burning emissions, exhibit distinctly different source characteristics compared to those for fossil-fuel combustion sources in south and south-east Asia. The PAH isomer ratios studied from different geographical locations in northern India also exhibit similar characteristics on the crossplot, suggesting their usefulness as diagnostic tracers of biomass burning emissions.

  14. Patterns in atmospheric carbonaceous aerosols in China: emission estimates and observed concentrations

    NASA Astrophysics Data System (ADS)

    Zhao, Y.

    2015-12-01

    To better understand the levels and trends of carbonaceous aerosol emissions and the resulting ambient concentrations in China, we update an emission inventory of anthropogenic organic carbon (OC) and elemental carbon (EC) and employ existing observational studies to analyze characteristics of these aerosols including temporal and spatial distributions, and the levels and shares of secondary organic carbon (SOC) in total OC. We further use ground observations to test the levels and inter-annual trends of the calculated national and provincial emissions of carbonaceous aerosols. The national OC emissions are estimated to have increased 29% from 2000 (2127 Gg) to 2012 (2749 Gg) and EC by 37% (from 1356 to 1857 Gg). Updated emission factors based on the most recent local field measurements, particularly for biofuel stoves, lead to considerably lower emissions of OC compared to previous inventories. Compiling observational data across the country, higher concentrations of OC and EC are found in northern and inland cities, while SOC/OC ratios are found in southern cities, due to the joint effects of primary emissions and meteorology. Higher OC/EC ratios are estimated at rural and remote sites compared to urban ones, attributed to more emissions of OC from biofuel use, more biogenic emissions of volatile organic compound (VOC) precursors to SOC, and/or transport of aged aerosols. For most sites, smaller SOC/OC is found for cold seasons, particularly at rural and remote sites, attributed partly to weaker atmospheric oxidation and SOC formation in winter. Enhanced SOC formation from oxidization and anthropogenic activities like biomass combustion is judged to have crucial effects on severe haze events characterized by high particle concentrations. Several observational studies indicate an increasing trend in ambient OC/EC (but not in OC or EC individually) from 2000 to 2010, confirming increased atmospheric oxidation of OC across the country. Combining the results of

  15. A comprehensive global inventory of atmospheric Antimony emissions from anthropogenic activities, 1995-2010.

    PubMed

    Tian, Hezhong; Zhou, JunRui; Zhu, Chuanyong; Zhao, Dan; Gao, Jiajia; Hao, Jiming; He, Mengchang; Liu, Kaiyun; Wang, Kun; Hua, Shenbing

    2014-09-02

    Antimony (Sb) and its compounds are considered as global pollutants due to their health risks and long-range transport characteristics. A comprehensive global inventory of atmospheric antimony emissions from anthropogenic activities during the period of 1995-2010 has been developed with specific estimation methods based on the relevant data available for different continents and countries. Our results indicate that the global antimony emissions have increased to a peak at about 2232 t (t) in 2005 and then declined gradually. Global antimony emissions in 2010 are estimated at about 1904 t (uncertainty of a 95% confidence interval (CI): -30% ∼ 67%), with fuel combustion as the major source category. Asia and Europe account for about 57% and 24%, respectively, of the global total emissions, and China, the United States, and Japan rank as the top three emitting countries. Furthermore, global antimony emissions are distributed into gridded cells with a resolution of 1° × 1°. Regions with high Sb emissions are generally concentrated in the Southeastern Asia and Western Europe, while South Africa, economically developed regions in the eastern U.S., and Mexico are also responsible for the high antimony emission intensity.

  16. Uncertainties of fluxes and 13C / 12C ratios of atmospheric reactive-gas emissions

    NASA Astrophysics Data System (ADS)

    Gromov, Sergey; Brenninkmeijer, Carl A. M.; Jöckel, Patrick

    2017-07-01

    We provide a comprehensive review of the proxy data on the 13C / 12C ratios and uncertainties of emissions of reactive carbonaceous compounds into the atmosphere, with a focus on CO sources. Based on an evaluated set-up of the EMAC model, we derive the isotope-resolved data set of its emission inventory for the 1997-2005 period. Additionally, we revisit the calculus required for the correct derivation of uncertainties associated with isotope ratios of emission fluxes. The resulting δ13C of overall surface CO emission in 2000 of -(25. 2 ± 0. 7) ‰ is in line with previous bottom-up estimates and is less uncertain by a factor of 2. In contrast to this, we find that uncertainties of the respective inverse modelling estimates may be substantially larger due to the correlated nature of their derivation. We reckon the δ13C values of surface emissions of higher hydrocarbons to be within -24 to -27 ‰ (uncertainty typically below ±1 ‰), with an exception of isoprene and methanol emissions being close to -30 and -60 ‰, respectively. The isotope signature of ethane surface emission coincides with earlier estimates, but integrates very different source inputs. δ13C values are reported relative to V-PDB.

  17. COMPILATION AND ANALYSES OF EMISSIONS INVENTORIES FOR THE NOAA ATMOSPHERIC CHEMISTRY PROJECT. PROGRESS REPORT, AUGUST 1997.

    SciTech Connect

    BENKOVITZ,C.M.

    1997-09-01

    Global inventories of anthropogenic emissions of oxides of nitrogen (NO{sub x}) for circa 1985 and 1990 and Non-Methane Volatile Organic Compounds (NMVOCs) for circa 1990 have been compiled by this project. Work on the inventories has been carried out under the umbrella of the Global Emissions Inventory Activity (GEIA) of the International Global Atmospheric Chemistry (IGAC) Program. The 1985 NO{sub x} inventory was compiled using default data sets of global emissions that were refined via the use of more detailed regional data sets; this inventory is being distributed to the scientific community at large as the GEIA Version 1A inventory. Global emissions of NO{sub x} for 1985 are estimated to be 21 Tg N y{sup -1}, with approximately 84% originating in the Northern Hemisphere. The 1990 inventories of NO{sub x} and NMVOCs were compiled using unified methodologies and data sets in collaboration with the Netherlands National Institute of Public Health and Environmental Protection (Rijksinstituut Voor Volksgezondheid en Milieuhygiene, RIVM) and the Division of Technology for Society of the Netherlands Organization for Applied Scientific Research, (IMW-TNO); these emissions will be used as the default estimates to be updated with more accurate regional data. The NMVOC inventory was gridded and speciated into 23 chemical categories. The resulting global emissions for 1990 are 31 Tg N yr{sup -1} for NO{sub x} and 173 Gg NMVOC yr{sup -1}. Emissions of NO{sub x} are highest in the populated and industrialized areas of eastern North America and across Europe, and in biomass burning areas of South America, Africa, and Asia. Emissions of NMVOCs are highest in biomass burning areas of South America, Africa, and Asia. The 1990 NO{sub x} emissions were gridded to 1{sup o} resolution using surrogate data, and were given seasonal, two-vertical-level resolution and speciated into NO and NO{sub 2} based on proportions derived from the 1985 GEIA Version 1B inventory. Global NMVOC

  18. The impact of residential combustion emissions on atmospheric aerosol, human health, and climate

    NASA Astrophysics Data System (ADS)

    Butt, E. W.; Rap, A.; Schmidt, A.; Scott, C. E.; Pringle, K. J.; Reddington, C. L.; Richards, N. A. D.; Woodhouse, M. T.; Ramirez-Villegas, J.; Yang, H.; Vakkari, V.; Stone, E. A.; Rupakheti, M.; Praveen, P. S.; van Zyl, P. G.; Beukes, J. P.; Josipovic, M.; Mitchell, E. J. S.; Sallu, S. M.; Forster, P. M.; Spracklen, D. V.

    2016-01-01

    Combustion of fuels in the residential sector for cooking and heating results in the emission of aerosol and aerosol precursors impacting air quality, human health, and climate. Residential emissions are dominated by the combustion of solid fuels. We use a global aerosol microphysics model to simulate the impact of residential fuel combustion on atmospheric aerosol for the year 2000. The model underestimates black carbon (BC) and organic carbon (OC) mass concentrations observed over Asia, Eastern Europe, and Africa, with better prediction when carbonaceous emissions from the residential sector are doubled. Observed seasonal variability of BC and OC concentrations are better simulated when residential emissions include a seasonal cycle. The largest contributions of residential emissions to annual surface mean particulate matter (PM2.5) concentrations are simulated for East Asia, South Asia, and Eastern Europe. We use a concentration response function to estimate the human health impact due to long-term exposure to ambient PM2.5 from residential emissions. We estimate global annual excess adult (> 30 years of age) premature mortality (due to both cardiopulmonary disease and lung cancer) to be 308 000 (113 300-497 000, 5th to 95th percentile uncertainty range) for monthly varying residential emissions and 517 000 (192 000-827 000) when residential carbonaceous emissions are doubled. Mortality due to residential emissions is greatest in Asia, with China and India accounting for 50 % of simulated global excess mortality. Using an offline radiative transfer model we estimate that residential emissions exert a global annual mean direct radiative effect between -66 and +21 mW m-2, with sensitivity to the residential emission flux and the assumed ratio of BC, OC, and SO2 emissions. Residential emissions exert a global annual mean first aerosol indirect effect of between -52 and -16 mW m-2, which is sensitive to the assumed size distribution of carbonaceous emissions

  19. Estimating Sulfur hexafluoride (SF6) emissions in China using atmospheric observations and inverse modeling

    NASA Astrophysics Data System (ADS)

    Fang, X.; Thompson, R.; Saito, T.; Yokouchi, Y.; Li, S.; Kim, J.; Kim, K.; Park, S.; Graziosi, F.; Stohl, A.

    2013-12-01

    With a global warming potential of around 22800 over a 100-year time horizon, sulfur hexafluoride (SF6) is one of the greenhouse gases regulated under the Kyoto Protocol. Global SF6 emissions have been increasing since circa the year 2000. The reason for this increase has been inferred to be due to rapidly increasing emissions in developing countries that are not obligated to report their annual emissions to the United Nations Framework Convention on Climate Change, notably China. In this study, SF6 emissions during the period 2006-2012 for China and other East Asian countries were determined using in-situ atmospheric measurements and inverse modeling. We performed various inversion sensitivity tests, which show the largest uncertainties in the a posteriori Chinese emissions are associated with the a priori emissions used and their uncertainty, the station network, as well as the meteorological input data. The overall relative uncertainty of the a posteriori emissions in China is estimated to be 17% in 2008. Based on sensitivity tests, we employed the optimal parameters in our inversion setup and performed yearly inversions for the study period. Inversion results show that the total a posteriori SF6 emissions from China increased from 1420 × 245 Mg/yr in 2006 to 2741 × 472 Mg/yr in 2009 and stabilized thereafter. The rapid increase in emissions reflected a fast increase in SF6 consumption in China, a result also found in bottom-up estimates. The a posteriori emission map shows high emissions concentrated in populated parts of China. During the period 2006-2012, emissions in northwestern and northern China peaked around the year 2009, while emissions in eastern, central and northeastern China grew gradually during almost the whole period. Fluctuating emissions are observed for southwestern China. These regional differences should be caused by changes of provincial SF6 usage and by shifts of usage among different sectors. Fig. 1. Footprint emission sensitivity

  20. Chlorine, fluorine, and sulfur emissions from Mount Erebus, Antarctica and estimated contributions to the Antarctic atmosphere

    SciTech Connect

    Zreda-Gostynska, G.; Kyle, P.R. ); Finnegan, D.L. )

    1993-09-15

    The authors report a study of the atmospheric release of gases from Mount Erebus, in continental Antarctica, over the period Dec 1986 to Jan 1991. This provides a case study of gas releases in a region of the planet almost devoid of anthropogenic sources. The discharge rates of chlorine, fluorine, and sulfur compounds have been monitored. The emission rates of HF and HCl were observed to double over this period to levels of 6 and 13.3 Gg/yr. Measurements were made from filter paper samples, relative to SO[sub 2] emission rates measured independently of the filter samples.

  1. OBSERVATIONAL EVIDENCE FOR A METAL-RICH ATMOSPHERE ON THE SUPER-EARTH GJ1214b

    SciTech Connect

    Desert, Jean-Michel; Jacob Bean; Berta, Zachory K.; Charbonneau, David; Irwin, Jonathan; Burke, Christopher J.; Kempton, Eliza Miller-Ricci; Fortney, Jonathan; Nutzman, Philip

    2011-04-20

    We report observations of two consecutive transits of the warm super-Earth exoplanet GJ 1214b at 3.6 and 4.5 {mu}m with the Infrared Array Camera instrument on board the Spitzer Space Telescope. The two transit light curves allow for the determination of the transit parameters for this system. We find these parameters to be consistent with the previously determined values and no evidence for transit timing variations. The main investigation consists of measuring the transit depths in each bandpass to constrain the planet's transmission spectrum. Fixing the system scale and impact parameters, we measure R{sub p} /R{sub *} = 0.1176{sup +0.0008}{sub -0.0009} and 0.1163{sup +0.0010}{sub -0.0008} at 3.6 and 4.5 {mu}m, respectively. Combining these data with the previously reported MEarth Observatory measurements in the red optical allows us to rule out a cloud-free, solar composition (i.e., hydrogen-dominated) atmosphere at 4.5{sigma} confidence. This independently confirms a recent finding that was based on a measurement of the planet's transmission spectrum using the Very Large Telescope (VLT). The Spitzer, MEarth, and VLT observations together yield a remarkably flat transmission spectrum over the large wavelength domain spanned by the data. Consequently, cloud-free atmospheric models require more than 30% metals (assumed to be in the form of H{sub 2}O) by volume to be consistent with all the observations.

  2. White light emission from silicon oxycarbide films prepared by using atmospheric pressure microplasma jet

    SciTech Connect

    Ding Yi; Shirai, Hajime

    2009-02-15

    An atmospheric pressure microplasma jet was employed as a deposition tool to fabricate silicon oxycarbide films from tetraethoxysilane-argon (Ar) mixture gas at room temperature. Resultant films exhibit intense visible emission under a 325 nm excitation which appears white to naked eyes in the range from {approx}1.75 to {approx}3.5 eV at room temperature. The origin of photoluminescence is attributed to the electron-hole pair recombination through neutral oxygen vacancies (NOVs) in the film. The density of NOV defects was found in the range from 3.48x10{sup 15} to 2.23x10{sup 16} cm{sup -3}. The photoluminescence quantum efficiencies were estimated to be 1.48%-4.15%. Present experiment results demonstrate that the silicon oxycarbide films prepared by using atmospheric pressure microplasma jet would be a competitive candidate for the development of white light emission devices.

  3. Mineral Dust Aerosol from Saharan Desert by Means of Atmospheric, Emission, Dispersion Modelling

    NASA Astrophysics Data System (ADS)

    Busillo, C.; Calastrini, F.; Guarnieri, F.; Pasqui, M.; Becagli, S.; Lucarelli, F.; Nava, S.; Udisti, R.

    2011-01-01

    The application of Numerical Prediction Models to mineral dust cycle is considered of prime importance in climate change due to aerosol and non-CO2 greenhouse gases. In this framework, a comprehensive atmospheric, emission, dispersion modelling system was developed in order to provide a regional characterization of Saharan dust intrusions over Mediterranean basin. The model is based on three different modules: the atmospheric model, the dust emission model and transport/deposition model. Numerical modelling simulations for a selected case study, June 2006, was carried out to test the modelling system. The evaluation of the performed analysis shows a good agreement with the in-situ measurements of some specific crustal markers in the PM10 fraction.

  4. Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications

    SciTech Connect

    Jokinen, Tuija; Berndt, Torsten; Makkonen, Risto; Kerminen, Veli-Matti; Junninen, Heikki; Paasonen, Pauli; Stratmann, Frank; Herrmann, Hartmut; Guenther, Alex B.; Worsnop, Douglas R.; Kulmala, M.; Ehn, Mikael K.; Sipila, Mikko

    2015-06-09

    Extremely low volatility organic compounds (ELVOC) are suggested to promote aerosol particle formation and cloud condensation nuclei (CCN) production in the atmosphere. We show that the capability of biogenic VOC (BVOC) to produce ELVOC depends strongly on their chemical structure and relative oxidant levels. BVOC with an endocyclic double bond, representative emissions from, e.g., boreal forests, efficiently produce ELVOC from ozonolysis. Compounds with exocyclic double bonds or acyclic compounds including isoprene, emission representative of the tropics, produce minor quantities of ELVOC, and the role of OH radical oxidation is relatively larger. Implementing these findings into a global modeling framework shows that detailed assessment of ELVOC production pathways is crucial for understanding biogenic secondary organic aerosol and atmospheric CCN formation.

  5. Constraining atmospheric ammonia emissions through new observations with an open-path, laser-based sensor

    NASA Astrophysics Data System (ADS)

    Sun, Kang

    As the third most abundant nitrogen species in the atmosphere, ammonia (NH3) is a key component of the global nitrogen cycle. Since the industrial revolution, humans have more than doubled the emissions of NH3 to the atmosphere by industrial nitrogen fixation, revolutionizing agricultural practices, and burning fossil fuels. NH3 is a major precursor to fine particulate matter (PM2.5), which has adverse impacts on air quality and human health. The direct and indirect aerosol radiative forcings currently constitute the largest uncertainties for future climate change predictions. Gas and particle phase NH3 eventually deposits back to the Earth's surface as reactive nitrogen, leading to the exceedance of ecosystem critical loads and perturbation of ecosystem productivity. Large uncertainties still remain in estimating the magnitude and spatiotemporal patterns of NH3 emissions from all sources and over a range of scales. These uncertainties in emissions also propagate to the deposition of reactive nitrogen. To improve our understanding of NH3 emissions, observational constraints are needed from local to global scales. The first part of this thesis is to provide quality-controlled, reliable NH3 measurements in the field using an open-path, quantum cascade laser-based NH3 sensor. As the second and third part of my research, NH3 emissions were quantified from a cattle feedlot using eddy covariance (EC) flux measurements, and the similarities between NH3 turbulent fluxes and those of other scalars (temperature, water vapor, and CO2) were investigated. The fourth part involves applying a mobile laboratory equipped with the open-path NH3 sensor and other important chemical/meteorological measurements to quantify fleet-integrated NH3 emissions from on-road vehicles. In the fifth part, the on-road measurements were extended to multiple major urban areas in both the US and China in the context of five observation campaigns. The results significantly improved current urban NH3

  6. Quantifying the uncertainties of a bottom-up emission inventory of anthropogenic atmospheric pollutants in China

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Nielsen, C. P.; Lei, Y.; McElroy, M. B.; Hao, J.

    2011-03-01

    studies, the results are not always consistent with those derived from satellite observations. The results thus represent an incremental research advance; while the analysis provides current estimates of uncertainty to researchers investigating Chinese and global atmospheric transport and chemistry, it also identifies specific needs in data collection and analysis to improve on them. Strengthened quantification of emissions of the included species and other, closely associated ones - notably CO2, generated largely by the same processes and thus subject to many of the same parameter uncertainties - is essential not only for science but for the design of policies to redress critical atmospheric environmental hazards at local, regional, and global scales.

  7. Quantifying the uncertainties of a bottom-up emission inventory of anthropogenic atmospheric pollutants in China

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Nielsen, C. P.; Lei, Y.; McElroy, M. B.; Hao, J.

    2010-11-01

    studies, the results are not always consistent with those derived from satellite observations. The results thus represent an incremental research advance; while the analysis provides current estimates of uncertainty to researchers investigating Chinese and global atmospheric transport and chemistry, it also identifies specific needs in data collection and analysis to improve on them. Strengthened quantification of emissions of the included species and other, closely associated ones - notably CO2, generated largely by the same processes and thus subject to many of the same parameter uncertainties - is essential not only for science but for the design of policies to redress critical atmospheric environmental hazards at local, regional, and global scales.

  8. Staggering reductions in atmospheric nitrogen dioxide across Canada in response to legislated transportation emissions reductions

    NASA Astrophysics Data System (ADS)

    Reid, Holly; Aherne, Julian

    2016-12-01

    It is well established that atmospheric nitrogen dioxide (NO2), associated mainly with emissions from transportation and industry, can have adverse effects on both human and ecosystem health. Specifically, atmospheric NO2 plays a role in the formation of ozone, and in acidic and nutrient deposition. As such, international agreements and national legislation, such as the On-Road Vehicle and Engine Emission Regulations (SOR/2003-2), and the Federal Agenda on Cleaner Vehicles, Engines and Fuel have been put into place to regulate and limit oxidized nitrogen emissions. The objective of this study was to assess the response of ambient air concentrations of NO2 across Canada to emissions regulations. Current NO2 levels across Canada were examined at 137 monitoring sites, and long-term annual and quarterly trends were evaluated for 63 continuous monitoring stations that had at least 10 years of data during the period 1988-2013. A non-parametric Mann-Kendall test (Z values) and Sen's slope estimate were used to determine monotonic trends; further changepoint analysis was used to determine periods with significant changes in NO2 air concentration and emissions time-series data. Current annual average NO2 levels in Canada range between 1.16 and 14.96 ppb, with the national average being 8.43 ppb. Provincially, average NO2 ranges between 3.77 and 9.25 ppb, with Ontario and British Columbia having the highest ambient levels of NO2. Long-term tend analysis indicated that the annual average NO2 air concentration decreased significantly at 87% of the stations (55 of 63), and decreased non-significantly at 10% (5 of 63) during the period 1998-2013. Concentrations increased (non-significantly) at only 3% (2 of 63) of the sites. Quarterly long-term trends showed similar results; significant decreases occurred at 84% (January-March), 88% (April-June), 83% (July-September), and 81% (October-December) of the sites. Declines in transportation emissions had the most influence on NO2 air

  9. Global SF6 emission estimates inferred from atmospheric observations - a test case for Kyoto reporting

    NASA Astrophysics Data System (ADS)

    Levin, I.; Naegler, T.

    2009-04-01

    Sulphur hexafluoride (SF6) is one of the strongest greenhouse gases per molecule in the atmosphere. SF6 emissions are also one of the six greenhouse gases targeted for reduction under the Kyoto Protocol. Here we present a long-term data set of globally distributed high-precision atmospheric SF6 observations which show an increase in mixing ratios from near zero in the 1970s to a global mean value of 6.3 ppt by the end of 2007. Because of its long atmospheric lifetime of around 3000 years, the accumulation of SF6 in the atmosphere is a direct measure of its global emissions: Analysis of our long-term data records implies a decrease of global SF6 sources after 1995, most likely due to emission reductions in industrialised countries. However, after 1998 the global SF6 source increases again, which is probably due to enhanced emissions from transition economies such as in China and India. Moreover, observed north-south concentration differences in SF6 suggest that emissions calculated from statistical (bottom-up) information and reported by Annex II parties to the United Nations Framework Convention on Climate Change (UNFCCC) may be too low by up to 50%. This clearly shows the importance and need for atmospheric (top-down) validation of Kyoto reporting which is only feasible with a dense world-wide observational network for greenhouse and other trace gases. Other members of the Global SF6 Trends Team: R. Heinz (1), D. Osusko (1), E. Cuevas (2), A. Engel (3), J. Ilmberger (1), R.L. Langenfelds (4), B. Neininger (5), C.v. Rohden (1), L.P. Steele (4), A. Varlagin (6), R. Weller (7), D.E. Worthy (8), S.A. Zimov (9) (1) Institut für Umweltphysik, University of Heidelberg, 69120 Heidelberg, Germany, (2) Centro de Investigación Atmosférica de Izaña, Instituto Nacional de Meteorología (INM), 38071 Santa Cruz de Tenerife, Spain, (3) Institut für Atmosphäre und Umwelt, J.W. Goethe Universität Frankfurt, 60438 Frankfurt/Main, Germany, (4) Centre for Australian Weather and

  10. Atmospheric Ammonia Emissions and a Nitrogen Mass Balance for a Dairy

    NASA Astrophysics Data System (ADS)

    Rumburg, B. P.; Mount, G. H.; Filipy, J. M.; Lamb, B.; Yonge, D.; Wetherelt, S.

    2003-12-01

    Atmospheric ammonia (NH3) emissions have many impacts on the environment and human health. Environmental NH3 impacts include terrestrial and aquatic eutrophication, soil acidification, and aerosol formation. Aerosols affect global radiative transfer and have been linked to human health effects. The global emissions of NH3 are estimated to be 45 Tg N yr-1 (Dentener and Crutzen, 1994) with most of the emissions coming from domestic animals. The largest per animal emission come from dairy cows at 33 kg N animal{-1} year{-1} versus 10 kg N animal{-1} {-1} for cattle. On a global scale the emissions uncertainty is about 25%, but local emissions are highly uncertain (Bouwman et al., 1997). Local emissions determination is required for proper treatment in air pollution models. The main sources of emission from dairies are the cow stalls where urea and manure react to form NH3, the storage lagoons where NH3 is the end product of microbial degradation and the disposal of the waste. There have been numerous studies of NH3 emissions in Europe but farming practices are quite different in Europe than in the U.S.. The impact of these differences on emissions is unknown. We have been studying the NH3 emissions from the Washington State University dairy for three years to develop a detailed emission model for use in a regional air pollution model. NH3 is measured using a short-path spectroscopic absorption near 200 nm with a sensitivity of a few ppbv and a time resolution of a few seconds. The open air short-path method is advantageous because it is self calibrating and avoids inlet wall adherence which is a major problem for most NH3 measurement techniques. A SF6 tracer technique has been used to measure fluxes from the three main emission sources: the cow stalls, anaerobic lagoon and the waste application to grass fields using a sprinkler system. Estimated yearly emissions from each source will be compared to a nitrogen mass balance model for the dairy.

  11. Hydrogen Cyanide Production due to Mid-Size Impacts in a Redox-Neutral N2-Rich Atmosphere

    NASA Astrophysics Data System (ADS)

    Kurosawa, Kosuke; Sugita, Seiji; Ishibashi, Ko; Hasegawa, Sunao; Sekine, Yasuhito; Ogawa, Nanako O.; Kadono, Toshihiko; Ohno, Sohsuke; Ohkouchi, Naohiko; Nagaoka, Yoichi; Matsui, Takafumi

    2013-06-01

    Cyanide compounds are amongst the most important molecules of the origin of life. Here, we demonstrate the importance of mid-size (0.1-1 km in diameter) hence frequent meteoritic impacts to the cyanide inventory on the early Earth. Subsequent aerodynamic ablation and chemical reactions with the ambient atmosphere after oblique impacts were investigated by both impact and laser experiments. A polycarbonate projectile and graphite were used as laboratory analogs of meteoritic organic matter. Spectroscopic observations of impact-generated ablation vapors show that laser irradiation to graphite within an N2-rich gas can produce a thermodynamic environment similar to that produced by oblique impacts. Thus, laser ablation was used to investigate the final chemical products after this aerodynamic process. We found that a significant fraction (>0.1 mol%) of the vaporized carbon is converted to HCN and cyanide condensates, even when the ambient gas contains as much as a few hundred mbar of CO2. As such, the column density of cyanides after carbon-rich meteoritic impacts with diameters of 600 m would reach ~10 mol/m2 over ~102 km2 under early Earth conditions. Such a temporally and spatially concentrated supply of cyanides may have played an important role in the origin of life.

  12. Hydrogen cyanide production due to mid-size impacts in a redox-neutral N2-rich atmosphere.

    PubMed

    Kurosawa, Kosuke; Sugita, Seiji; Ishibashi, Ko; Hasegawa, Sunao; Sekine, Yasuhito; Ogawa, Nanako O; Kadono, Toshihiko; Ohno, Sohsuke; Ohkouchi, Naohiko; Nagaoka, Yoichi; Matsui, Takafumi

    2013-06-01

    Cyanide compounds are amongst the most important molecules of the origin of life. Here, we demonstrate the importance of mid-size (0.1-1 km in diameter) hence frequent meteoritic impacts to the cyanide inventory on the early Earth. Subsequent aerodynamic ablation and chemical reactions with the ambient atmosphere after oblique impacts were investigated by both impact and laser experiments. A polycarbonate projectile and graphite were used as laboratory analogs of meteoritic organic matter. Spectroscopic observations of impact-generated ablation vapors show that laser irradiation to graphite within an N2-rich gas can produce a thermodynamic environment similar to that produced by oblique impacts. Thus, laser ablation was used to investigate the final chemical products after this aerodynamic process. We found that a significant fraction (>0.1 mol%) of the vaporized carbon is converted to HCN and cyanide condensates, even when the ambient gas contains as much as a few hundred mbar of CO2. As such, the column density of cyanides after carbon-rich meteoritic impacts with diameters of 600 m would reach ~10 mol/m(2) over ~10(2) km(2) under early Earth conditions. Such a temporally and spatially concentrated supply of cyanides may have played an important role in the origin of life.

  13. Atmospheric emissions of F, As, Se, Hg, and Sb from coal-fired power and heat generation in China.

    PubMed

    Chen, Jian; Liu, Guijian; Kang, Yu; Wu, Bin; Sun, Ruoyu; Zhou, Chuncai; Wu, Dun

    2013-02-01

    Coal is one of the major energy resources in China, with nearly half of produced Chinese coal used for power and heat generation. The large use of coal for power and heat generation in China may result in significant atmospheric emissions of toxic volatile trace elements (i.e. F, As, Se, Hg, and Sb). For the purpose of estimating the atmospheric emissions from coal-fired power and heat generation in China, a simple method based on coal consumption, concentration and emission factor of trace element was adopted to calculate the gaseous emissions of elements F, As, Se, Hg, and Sb. Results indicate that about 162161, 236, 637, 172, and 33 t F, As, Se, Hg, and Sb, respectively, were introduced into atmosphere from coal combustion by power and heat generation in China in 2009. The atmospheric emissions of F, As, Se, Hg, and Sb by power and heat generation increased from 2005 to 2009 with increasing coal consumptions.

  14. Chloroform formation in Arctic and Subarctic soils - mechanism and emissions to the atmosphere

    NASA Astrophysics Data System (ADS)

    Albers, Christian N.; Johnsen, Anders R.; Jacobsen, Ole S.

    2015-04-01

    It is well established that halogenated organic compounds are formed naturally in the terrestrial environment. These compounds include volatiles such as trihalomethanes that may escape to the atmosphere. In deed most of the atmospheric chloroform (and other trihalomethane species) is regarded to have a natural origin. This origin may be both marine and terrestrial. Chloroform formation in soil has been reported in a number of studies, mostly conducted in temperate and (sub-) tropical environments. We hereby report that also colder soils emit chloroform naturally. We measured in situ the fluxes of chloroform from soil to atmosphere in 6 Subarctic and 5 Arctic areas covering different dwarf heath, wetland and forest biotopes in Greenland and Northern Sweden. Emissions were largest from the forested areas, but all areas emitted measurable amounts of chloroform. Also the brominated analog bromodichloromethane was formed in Arctic and Subarctic soils but the fluxes to the atmosphere were much lower than the corresponding chloroform emissions. No other volatile poly-halogenated organic compounds were found to be emitted from the study areas. It has previously been proposed that chloroform is formed in temperate forest soils through trichloroacetyl intermediates formed by unspecific enzymatic chlorination of soil organic matter. We found positive relationships between chloroform emissions and the concentration of trichloroacetyl groups in soil within the various biotopes. The hydrolysis of trichloroacetyl compounds is, however, very pH dependent, excluding a simple relationship between trichloroacetyl concentration and chloroform emission in any given soil. However, our results show that at low pH, turnover time of soil trichloroacetyl compounds may be counted in decades while at pH above 6, turnover time may be just a few months. We found no relationship between trichloroacetyl concentration and total organic chlorine concentration in the soils indicating that more than

  15. [Mercury Distribution Characteristics and Atmospheric Mercury Emission Factors of Typical Waste Incineration Plants in Chongqing].

    PubMed

    Duan, Zhen-ya; Su, Hai-tao; Wang, Feng-yang; Zhang, Lei; Wang, Shu-xiao; Yu, Bin

    2016-02-15

    Waste incineration is one of the important atmospheric mercury emission sources. The aim of this article is to explore the atmospheric mercury pollution level of waste incineration industry from Chongqing. This study investigated the mercury emissions from a municipal solid waste incineration plant and a medical waste incineration plant in Chongqing. The exhaust gas samples in these two incineration plants were obtained using USA EPA 30B method. The mercury concentrations in the fly ash and bottom ash samples were analyzed. The results indicated that the mercury concentrations of the municipal solid waste and medical waste incineration plant in Chongqing were (26.4 +/- 22.7) microg x m(-3) and (3.1 +/- 0.8) microg x m(-3) in exhaust gas respectively, (5279.2 +/- 798.0) microg x kg(-1) and (11,709.5 +/- 460.5) microg x kg(-1) in fly ash respectively. Besides, the distribution proportions of the mercury content from municipal solid waste and medical waste in exhaust gas, fly ash, and bottom ash were 34.0%, 65.3%, 0.7% and 32.3%, 67.5%, 0.2% respectively; The mercury removal efficiencies of municipal solid waste and medical waste incineration plants were 66.0% and 67.7% respectively. The atmospheric mercury emission factors of municipal solid waste and medical waste incineration plants were (126.7 +/- 109.0) microg x kg(-1) and (46.5 +/- 12.0) microg x kg(-1) respectively. Compared with domestic municipal solid waste incineration plants in the Pearl River Delta region, the atmospheric mercury emission factor of municipal solid waste incineration plant in Chongqing was lower.

  16. CarbonTracker-CH4: an assimilation system for estimating emissions of atmospheric methane

    NASA Astrophysics Data System (ADS)

    Bruhwiler, L. M.; Dlugokencky, E.; Masarie, K.; Ishizawa, M.; Andrews, A.; Miller, J.; Sweeney, C.; Tans, P.; Worthy, D.

    2014-01-01

    We describe an assimilation system for atmospheric methane (CH4), CarbonTracker-CH4, and demonstrate the diagnostic value of global or zonally averaged CH4 abundances for evaluating the results. We show that CarbonTracker-CH4 is able to simulate the observed zonal average mole fractions and capture inter-annual variability in emissions quite well at high northern latitudes (53-90° N). CarbonTracker-CH4 estimates of total fluxes at high northern latitudes are about 81 Tg CH4 yr-1, about 12 Tg CH4 yr-1 (13%) lower than prior estimates, a result that is consistent with other atmospheric inversions. Emissions from European wetlands are decreased by 30%, a result consistent with previous; however, emissions from wetlands in Boreal Eurasia are increased relative to the prior estimate. Although CarbonTracker-CH4 does not estimate increases in emissions from high northern latitudes for 2000 through 2010, significant inter-annual variability in high northern latitude fluxes is recovered. During the exceptionally warm Arctic summer of 2007, estimated emissions were greater than the decadal average by 4.4 Tg CH4 yr-1. In 2008, temperatures returned to more normal values over Arctic North America while they stayed above normal over Arctic Eurasia. CarbonTracker-CH4 estimates were 2.4 Tg CH4 yr-1 higher than the decadal average, and the anomalous emissions occurred over Arctic Eurasia, suggesting that the data allow discrimination between these two source regions. Also, the emission estimates respond to climate variability without having the system constrained by climate parameters. CarbonTracker-CH4 estimates for temperate latitudes are only slightly increased over prior estimates, but about 10 Tg CH4 yr-1 is redistributed from Asia to North America. We used time invariant prior flux estimates, so for the period from 2000 to 2006, when the growth rate of global atmospheric CH4 was very small, the assimilation does not produce increases in natural or anthropogenic emissions in

  17. Sensitivity of biomarkers to changes in chemical emissions in the Earth’s Proterozoic atmosphere

    NASA Astrophysics Data System (ADS)

    Grenfell, J. L.; Gebauer, S.; von Paris, P.; Godolt, M.; Hedelt, P.; Patzer, A. B. C.; Stracke, B.; Rauer, H.

    2011-01-01

    The search for life beyond the Solar System is a major activity in exoplanet science. However, even if an Earth-like planet were to be found, it is unlikely to be at a similar stage of evolution as the modern Earth. It is therefore of interest to investigate the sensitivity of biomarker signals for life as we know it for an Earth-like planet but at earlier stages of evolution. Here, we assess biomarkers, i.e. species almost exclusively associated with life, in present-day and in 10% present atmospheric level oxygen atmospheres corresponding to the Earth's Proterozoic period. We investigate the impact of proposed enhanced microbial emissions of the biomarker nitrous oxide, which photolyses to form nitrogen oxides which can destroy the biomarker ozone. A major result of our work is regardless of the microbial activity producing nitrous oxide in the early anoxic ocean, a certain minimum ozone column can be expected to persist in Proterozoic-type atmospheres due to a stabilising feedback loop between ozone, nitrous oxide and the ultraviolet radiation field. Atmospheric nitrous oxide columns were enhanced by a factor of 51 for the Proterozoic "Canfield ocean" scenario with 100 times increased nitrous oxide surface emissions. In such a scenario nitrous oxide displays prominent spectral features, so may be more important as a biomarker than previously considered in such cases. The run with "Canfield ocean" nitrous oxide emissions enhanced by a factor of 100 also featured additional surface warming of 3.5 K. Our results suggest that the Proterozoic ozone layer mostly survives the changes in composition which implies that it is indeed a good atmospheric biomarker.

  18. Soil greenhouse gas emissions reduce the contribution of mangrove plants to the atmospheric cooling effect

    NASA Astrophysics Data System (ADS)

    Chen, Guangcheng; Chen, Bin; Yu, Dan; Tam, Nora F. Y.; Ye, Yong; Chen, Shunyang

    2016-12-01

    Mangrove soils have been recognized as sources of greenhouse gases, but the atmospheric fluxes are poorly characterized, and their adverse warming effect has rarely been considered with respect to the potential contribution of mangrove wetlands to climate change mitigation. The current study balanced the warming effect of soil greenhouse gas emissions with the plant carbon dioxide (CO2) sequestration rate derived from the plants’ net primary production in a productive mangrove wetland in South China to assess the role of mangrove wetlands in reducing the atmospheric warming effect. Soil characteristics were also studied in the summer to examine their relationships with gas fluxes. The soil to atmosphere fluxes of nitrous oxide (N2O), methane (CH4) and CO2 ranged from -1.6 to 50.0 μg m-2 h-1, from -1.4 to 5360.1 μg m-2 h-1 and from -31 to 512 mg m-2 h-1, respectively, which indicated that the mangrove soils act as sources of greenhouse gases in this area. The gas fluxes were higher in summer than in the cold seasons and were variable across mangrove sites. Gas fluxes in summer were positively correlated with the soil organic carbon, total nitrogen, and ammonia contents. The mangrove plants sequestered a considerable amount of atmospheric CO2 at rates varying from 3652 to 7420 g CO2 m-2 yr-1. The ecosystem acted as a source of CH4 and N2O gases but was a more intense CO2 sink. However, the warming effect of soil gas emissions accounted for 9.3-32.7% of the plant CO2 sequestration rate, partially reducing the benefit of mangrove plants, and the two trace gases comprised 9.7-33.2% of the total warming effect. We therefore propose that an assessment of the reduction of atmospheric warming effects by a mangrove ecosystem should consider both soil greenhouse gas emissions and plant CO2 sequestration.

  19. The effect of anthropogenic emissions corrections on the seasonal cycle of atmospheric CO2

    NASA Astrophysics Data System (ADS)

    Brooks, B. J.; Hoffman, F. M.; Mills, R. T.; Erickson, D. J.; Blasing, T. J.

    2009-12-01

    A previous study (Erickson et al. 2008) approximated the monthly global emission estimates of anthropogenic CO2 by applying a 2-harmonic Fourier expansion with coefficients as a function of latitude to annual CO2 flux estimates derived from United States data (Blasing et al. 2005) that were extrapolated globally. These monthly anthropogenic CO2 flux estimates were used to model atmospheric concentrations using the NASA GEOS-4 data assimilation system. Local variability in the amplitude of the simulated CO2 seasonal cycle were found to be on the order of 2-6 ppmv. Here we used the same Fourier expansion to seasonally adjust the global annual fossil fuel CO2 emissions from the SRES A2 scenario. For a total of four simulations, both the annual and seasonalized fluxes were advected in two configurations of the NCAR Community Atmosphere Model (CAM) used in the Carbon-Land Model Intercomparison Project (C-LAMP). One configuration used the NCAR Community Land Model (CLM) coupled with the CASA‧ (carbon only) biogeochemistry model and the other used CLM coupled with the CN (coupled carbon and nitrogen cycles) biogeochemistry model. All four simulations were forced with observed sea surface temperatures and sea ice concentrations from the Hadley Centre and a prescribed transient atmospheric CO2 concentration for the radiation and land forcing over the 20th century. The model results exhibit differences in the seasonal cycle of CO2 between the seasonally corrected and uncorrected simulations. Moreover, because of differing energy and water feedbacks between the atmosphere model and the two land biogeochemistry models, features of the CO2 seasonal cycle were different between these two model configurations. This study reinforces previous findings that suggest that regional near-surface atmospheric CO2 concentrations depend strongly on the natural sources and sinks of CO2, but also on the strength of local anthropogenic CO2 emissions and geographic position. This work further

  20. Monoterpene and herbivore-induced emissions from cabbage plants grown at elevated atmospheric CO 2 concentration

    NASA Astrophysics Data System (ADS)

    Vuorinen, Terhi; Reddy, G. V. P.; Nerg, Anne-Marja; Holopainen, Jarmo K.

    The warming of the lower atmosphere due to elevating CO 2 concentration may increase volatile organic compound (VOC) emissions from plants. Also, direct effects of elevated CO 2 on plant secondary metabolism are expected to lead to increased VOC emissions due to allocation of excess carbon on secondary metabolites, of which many are volatile. We investigated how growing at doubled ambient CO 2 concentration affects emissions from cabbage plants ( Brassica oleracea subsp. capitata) damaged by either the leaf-chewing larvae of crucifer specialist diamondback moth ( Plutella xylostella L.) or generalist Egyptian cotton leafworm ( Spodoptera littoralis (Boisduval)). The emission from cabbage cv. Lennox grown in both CO 2 concentrations, consisted mainly of monoterpenes (sabinene, limonene, α-thujene, 1,8-cineole, β-pinene, myrcene, α-pinene and γ-terpinene). ( Z)-3-Hexenyl acetate, sesquiterpene ( E, E)- α-farnesene and homoterpene ( E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) were emitted mainly from herbivore-damaged plants. Plants grown at 720 μmol mol -1 of CO 2 had significantly lower total monoterpene emissions per shoot dry weight than plants grown at 360 μmol mol -1 of CO 2, while damage by both herbivores significantly increased the total monoterpene emissions compared to intact plants. ( Z)-3-Hexenyl acetate, ( E, E)- α-farnesene and DMNT emissions per shoot dry weight were not affected by the growth at elevated CO 2. The emission of DMNT was significantly enhanced from plants damaged by the specialist P. xylostella compared to the plants damaged by the generalist S. littoralis. The relative proportions of total monoterpenes and total herbivore-induced compounds of total VOCs did not change due to the growth at elevated CO 2, while insect damage increased significantly the proportion of induced compounds. The results suggest that VOC emissions that are induced by the leaf-chewing herbivores will not be influenced by elevated CO 2 concentration.

  1. Atmospheric ammonia over China: emission estimates and impacts on air quality

    NASA Astrophysics Data System (ADS)

    Zhang, Lin; Zhao, Yuanhong; Chen, Youfan; Henze, Daven

    2016-04-01

    Ammonia (NH3) in the atmosphere is an important precursor of inorganic aerosols, and its deposition through wet and dry processes can cause adverse effects on ecosystems. The ammonia emissions over China are particularly large due to intensive agricultural activities, yet our current estimates of Chinese ammonia emissions and associated consequences on air quality are subject to large errors. Here we use the GEOS-Chem chemical transport model and its adjoint model to better quantify this issue. The TES satellite observations of ammonia concentrations and surface measurements of wet deposition fluxes are assimilated into the model to constrain the ammonia emissions over China. Optimized emissions show a strong seasonal variability with emissions in summer a factor of 3 higher than winter. We improve the bottom-up estimate of Chinese ammonia emissions from fertilizer use by using more practical feritilizer application rates for different crop types, which explains most of the discrepancies between our top-down estimates and prior emission estimates. We further use the GEOS-Chem adjoint at 0.25x0.3125 degree resolution to examine the sources contributing to the PM2.5 air pollution over North China. We show that wintertime PM2.5 over Beijing is largely contributed by residential and industrial sources, and ammonia emissions from agriculture activities. PM2.5 concentrations over North China are particularly sensitive to NH3 emissions in cold seasons due to strong nitrate formation. By converting shorted-lived nitric acid to aerosol nitrate, NH3 significantly promotes the regional transport influences of PM2.5 sources.

  2. Modeling Atmospheric Emissions and Calculating Mortality Rates Associated with High Volume Hydraulic Fracturing Transportation

    NASA Astrophysics Data System (ADS)

    Mathews, Alyssa

    Emissions from the combustion of fossil fuels are a growing pollution concern throughout the global community, as they have been linked to numerous health issues. The freight transportation sector is a large source of these emissions and is expected to continue growing as globalization persists. Within the US, the expanding development of the natural gas industry is helping to support many industries and leading to increased transportation. The process of High Volume Hydraulic Fracturing (HVHF) is one of the newer advanced extraction techniques that is increasing natural gas and oil reserves dramatically within the US, however the technique is very resource intensive. HVHF requires large volumes of water and sand per well, which is primarily transported by trucks in rural areas. Trucks are also used to transport waste away from HVHF well sites. This study focused on the emissions generated from the transportation of HVHF materials to remote well sites, dispersion, and subsequent health impacts. The Geospatial Intermodal Freight Transport (GIFT) model was used in this analysis within ArcGIS to identify roadways with high volume traffic and emissions. High traffic road segments were used as emissions sources to determine the atmospheric dispersion of particulate matter using AERMOD, an EPA model that calculates geographic dispersion and concentrations of pollutants. Output from AERMOD was overlaid with census data to determine which communities may be impacted by increased emissions from HVHF transport. The anticipated number of mortalities within the impacted communities was calculated, and mortality rates from these additional emissions were computed to be 1 in 10 million people for a simulated truck fleet meeting stricter 2007 emission standards, representing a best case scenario. Mortality rates due to increased truck emissions from average, in-use vehicles, which represent a mixed age truck fleet, are expected to be higher (1 death per 341,000 people annually).

  3. Correcting atmospheric effects in thermal ground observations for hyperspectral emissivity estimation

    NASA Astrophysics Data System (ADS)

    Timmermans, Joris; Buitrago, Maria

    2014-05-01

    Knowledge of Land surface temperature is of crucial importance in energy balance studies and environmental modeling. Accurate retrieval of land surface temperature (LST) demands detailed knowledge of the land surface emissivity. Measured radiation by remote sensing sensors to land surface temperature can only be performed using a-priori knowledge of the emissivity. Uncertainties in the retrieval of this emissivity can cause huge errors in LST estimations. The retrieval of emissivity (and LST) is per definition an underdetermined inversion, as only one observation is made while two variables are to be estimated. Several researches have therefore been performed on measuring emissivity, such as the normalized emissivity method, the temperature-emissivity separation (TES) using the minimum and maximum difference of emissivity and the use of vegetation indices. In each of these approaches atmospherically corrected radiance measurements by remote sensing sensors are correlated to ground measurements. Usually these ground measurements are performed with the ground equivalent of the remote sensing sensors; the CIMEL 312-2 has the same spectral bands as ASTER. This way parameterizations acquired this way are only usable for specific sensors and need to be redone for newer sensors. Recently hyperspectral thermal radiometers, such as the MIDAC, have been developed that can solve this problem. By using hyperspectral observations of emissivity, together with sensor simulators, ground measurements of different satellite sensor can be simulated. This facilitates the production of validation data for the different TES algorithms. However before such measurements can be performed extra steps of processing need to be performed. Atmospheric correction becomes more important in hyperspectral observations than for broadband observations, as energy levels measured per band is lower. As such the atmosphere has a relative larger contribution if bandwidths become smaller. The goal of this

  4. Natural gas fugitive emissions rates constrained by global atmospheric methane and ethane.

    PubMed

    Schwietzke, Stefan; Griffin, W Michael; Matthews, H Scott; Bruhwiler, Lori M P

    2014-07-15

    The amount of methane emissions released by the natural gas (NG) industry is a critical and uncertain value for various industry and policy decisions, such as for determining the climate implications of using NG over coal. Previous studies have estimated fugitive emissions rates (FER)--the fraction of produced NG (mainly methane and ethane) escaped to the atmosphere--between 1 and 9%. Most of these studies rely on few and outdated measurements, and some may represent only temporal/regional NG industry snapshots. This study estimates NG industry representative FER using global atmospheric methane and ethane measurements over three decades, and literature ranges of (i) tracer gas atmospheric lifetimes, (ii) non-NG source estimates, and (iii) fossil fuel fugitive gas hydrocarbon compositions. The modeling suggests an upper bound global average FER of 5% during 2006-2011, and a most likely FER of 2-4% since 2000, trending downward. These results do not account for highly uncertain natural hydrocarbon seepage, which could lower the FER. Further emissions reductions by the NG industry may be needed to ensure climate benefits over coal during the next few decades.

  5. Emission rate estimation through data assimilation of gamma dose measurements in a Lagrangian atmospheric dispersion model.

    PubMed

    Tsiouri, V; Kovalets, I; Andronopoulos, S; Bartzis, J G

    2012-01-01

    This paper presents an efficient algorithm for estimating the unknown emission rate of radionuclides in the atmosphere following a nuclear accident. The algorithm is based on assimilation of gamma dose rate measured data in a Lagrangian atmospheric dispersion model. Such models are used in the framework of nuclear emergency response systems (ERSs). It is shown that the algorithm is applicable in both deterministic and stochastic modes of operation of the dispersion model. The method is evaluated by computational simulations of a 3-d field experiment on atmospheric dispersion of ⁴¹Ar emitted routinely from a research reactor. Available measurements of fluence rate (photons flux) in air are assimilated in the Lagrangian dispersion model DIPCOT and the ⁴¹Ar emission rate is estimated. The statistical analysis shows that the model-calculated emission rates agree well with the real ones. In addition the model-predicted fluence rates at the locations of the sensors, which were not used in the data assimilation procedure are in better agreement with the measurements. The first evaluation results of the method presented in this study show that the method performs satisfactorily and therefore it is applicable in nuclear ERSs provided that more comprehensive validation studies will be performed.

  6. Nitrous oxide emissions to the atmosphere from an artificially oxygenated lake

    SciTech Connect

    Mengis, M.; Gaechter, R.; Wehrli, B.

    1996-05-01

    Nitrous oxide (N{sub 2}O) production at the sediment surface of eutrophic Lake Baldegg was quantified with three independent methods: pore-water samplers, benthic chambers, and mass balances of the aerated-oxygenated hypolimnion. N{sub 2}O production at the sediment surface was the most important source in this lake and led to an accumulation in the hypolimnion during summer stratification. Highest rates of N{sub 2}O emission to the atmosphere (24 {mu}mol m{sup {minus}2} d{sup {minus}1}) were observed after the onset of winter overturn, when hypolimnetic water enriched in N{sub 2}O came in contact with the atmosphere. During summer stratification N{sub 2}O emissions to the atmosphere decreased to {approximately}4 {mu}mol m{sup {minus}2} d {sup {minus}1}. The winter fluxes are close to the highest reported N{sub 2}O emissions from marine systems. 23 refs., 4 figs., 2 tabs.

  7. Atmospheric variability and emissions of halogenated trace gases near New York City

    NASA Astrophysics Data System (ADS)

    Santella, Nicholas; Ho, David T.; Schlosser, Peter; Gottlieb, Elaine; Munger, William J.; Elkins, James W.; Dutton, Geoffrey S.

    2012-02-01

    Elevated mixing ratios of chlorofluorocarbons (CFC-11 and CFC-12), and sulfur hexafluoride (SF 6) have been observed at Lamont-Doherty Earth Observatory (LDEO), located approximately 25 km north of New York City (NYC). Emissions and transport of these gases are of interest because of their global warming potential, the role of CFCs in depletion of stratospheric ozone and information they provide on the transport of atmospheric pollutants. Comparison of trace gas time series with meteorological data indicates that both NYC and the region to the southwest (New Jersey and the Philadelphia -Washington DC area) are significant sources of CFCs, and confirms that NYC is an unusually large source of SF 6. From 1996 to 2005 the elevation of CFC-12 mixing ratio above that of the remote (well mixed) atmosphere has decreased on average by 5.2 ± 0.6 ppt y -1, whereas that of CFC-11 has not changed significantly (0.0 ± 2.0 ppt y -1). From 1998 to 2006, the elevation of SF 6 mixing ratios above that of the remote atmosphere declined by 0.4 ± 0.1 ppt y -1. Time series of the same gases measured at Harvard Forest, 205 km northeast of LDEO, demonstrate transport of air masses with elevated levels of these gases from their source region to central Massachusetts. Emissions in the local area around LDEO were quantified through analysis of diurnal cycles. Local CFC-12 emissions decreased ca. 95% between 1996 and 2005 while CFC-11 emission decreased ca. 51% during the same period. Local SF 6 emissions decreased by 47% between 1998 and 2005.

  8. Annual emissions of mercury to the atmosphere from natural sources in Nevada and California

    USGS Publications Warehouse

    Coolbaugh, M.F.; Gustin, M.S.; Rytuba, J.J.

    2002-01-01

    The impact of natural source emissions on atmospheric mercury concentrations and the biogeochemical cycle of mercury is not known. To begin to assess this impact, mercury emissions to the atmosphere were scaled up for three areas naturally enriched in mercury: the Steamboat Springs geothermal area, Nevada, the New Idria mercury mining district, California, and the Medicine Lake volcano, California. Data used to scale up area emissions included mercury fluxes, measured in-situ using field flux chambers, from undisturbed and disturbed geologic substrates, and relationships between mercury emissions and geologic rock types, soil mercury concentrations, and surface heat flux. At select locations mercury fluxes were measured for 24 h and the data were used to adjust fluxes measured at different times of the day to give an average daily flux. This adjustment minimized daily temporal variability, which is observed for mercury flux because of light and temperature effects. Area emissions were scaled spatially and temporally with GIS software. Measured fluxes ranged from 0.3 to approximately 50 ng m-2 h-1 at undisturbed sites devoid of mercury mineralization, and to greater than 10,000 ng m-2 h-1 from substrates that were in areas of mercury mining. Area-averaged fluxes calculated for bare soil at Steamboat Springs, New Idria, and Medicine Lake of 181, 9.2, and 2 ng m-2 h-1, respectively, are greater than fluxes previously ascribed to natural non-point sources, indicating that these sources may be more significant contributors of mercury to the atmosphere than previously realized.

  9. Methane emission to the atmosphere from landfills in the Canary Islands

    NASA Astrophysics Data System (ADS)

    Hernández, Pedro A.; Asensio-Ramos, María; Rodríguez, Fátima; Alonso, Mar; García-Merino, Marta; Amonte, Cecilia; Melián, Gladys V.; Barrancos, José; Rodríguez-Delgado, Miguel A.; Hernández-Abad, Marta; Pérez, Erica; Alonso, Monica; Tassi, Franco; Raco, Brunella; Pérez, Nemesio M.

    2017-04-01

    Methane (CH4) is one of the most powerful greenhouse gases, and is increasing in the atmosphere by 0.6% each year (Intergovernmental Panel on Climate Change, IPCC, 2013). This gas is produced in landfills in large quantities following the anaerobic degradation of organic matter. The IPCC has estimated that more than 10% of the total anthropogenic emissions of CH4 are originated in landfills. Even after years of being no operative (closed), a significant amount of landfill gas could be released to the atmosphere through its surface as diffuse or fugitive degassing. Many landfills currently report their CH4 emissions to the atmosphere using model-based methods, which are based on the rate of production of CH4, the oxidation rate of CH4 and the amount of CH4 recovered (Bingemer and Crutzen, 1987). This approach often involves large uncertainties due to inaccuracies of input data and many assumptions in the estimation. In fact, the estimated CH4 emissions from landfills in the Canary Islands published by the Spanish National Emission and Pollutant Sources Registration (PRTR-Spain) seem to be overestimated due to the use of protocols and analytical methodologies based on mathematical models. For this reason, direct measurements to estimate CH4 emissions in landfills are essential to reduce this uncertainty. In order to estimate the CH4 emissions to the atmosphere from landfills in the Canary Islands 23 surveys have been performed since 1999. Each survey implies hundreds of CO2and CH4 efflux measurements covering the landfill surface area. Surface landfill CO2 efflux measurements were carried out at each sampling site by means of a portable non-dispersive infrared spectrophotometer (NDIR) model LICOR Li800 following the accumulation chamber method. Samples of landfill gases were taken in the gas accumulated in the chamber and CO2 and CH4 were analyzed using a double channel VARIAN 4900 micro-GC. The CH4 efflux measurent was computed combining CO2 efflux and CH4/CO2 ratio

  10. CarbonTracker-CH4: an assimilation system for estimating emissions of atmospheric methane

    NASA Astrophysics Data System (ADS)

    Bruhwiler, L.; Dlugokencky, E.; Masarie, K.; Ishizawa, M.; Andrews, A.; Miller, J.; Sweeney, C.; Tans, P.; Worthy, D.

    2014-08-01

    We describe an assimilation system for atmospheric methane (CH4), CarbonTracker-CH4, and demonstrate the diagnostic value of global or zonally averaged CH4 abundances for evaluating the results. We show that CarbonTracker-CH4 is able to simulate the observed zonal average mole fractions and capture inter-annual variability in emissions quite well at high northern latitudes (53-90° N). In contrast, CarbonTracker-CH4 is less successful in the tropics where there are few observations and therefore misses significant variability and is more influenced by prior flux estimates. CarbonTracker-CH4 estimates of total fluxes at high northern latitudes are about 81 ± 7 Tg CH4 yr-1, about 12 Tg CH4 yr-1 (13%) lower than prior estimates, a result that is consistent with other atmospheric inversions. Emissions from European wetlands are decreased by 30%, a result consistent with previous work by Bergamaschi et al. (2005); however, unlike their results, emissions from wetlands in boreal Eurasia are increased relative to the prior estimate. Although CarbonTracker-CH4 does not estimate an increasing trend in emissions from high northern latitudes for 2000 through 2010, significant inter-annual variability in high northern latitude fluxes is recovered. Exceptionally warm growing season temperatures in the Arctic occurred in 2007, a year that was also anonymously wet. Estimated emissions from natural sources were greater than the decadal average by 4.4 ± 3.8 Tg CH4 yr-1 in 2007. CarbonTracker-CH4 estimates for temperate latitudes are only slightly increased over prior estimates, but about 10 Tg CH4 yr-1 is redistributed from Asia to North America. This difference exceeds the estimated uncertainty for North America (±3.5 Tg CH4 yr-1). We used time invariant prior flux estimates, so for the period from 2000 to 2006, when the growth rate of global atmospheric CH4 was very small, the assimilation does not produce increases in natural or anthropogenic emissions in contrast to bottom

  11. Dynamical Models of Mira Atmospheres: Shocks, Limb Functions, and MG II Emission

    NASA Astrophysics Data System (ADS)

    Beach, Thomas Eugene

    1990-01-01

    Dynamic atmosphere models of Mira-type stars, prepared using a code developed by G. H. Bowen, were analyzed to determine observational implications of the models and suggest improvements to the code and model parameters. Three specific areas were addressed: Shock morphology, limb functions, and Mg II emission. The long-period, fundamental-mode models used in this study exhibit an unexpected shock morphology. In addition to the "main" shock, which forms as the radially pulsating surface of the Mira moves outward and is observed to travel out through atmosphere, a "preliminary" shock structure forms as rebounding layers of the atmosphere fall back onto lower layers. The preliminary shock remains deep in the atmosphere until overrun by the outward-moving main shock. The energy dissipated by the preliminary shock usually exceeds that dissipated by the main shock, and has important effects on the light curve. The dynamic atmosphere models exhibit radial extension of the atmosphere and post-shock emission that alter the limb function (limb darkening/brightening) of the models. The effects on stellar angular diameters measured by lunar occultation technique are calculated. The results show that the usual procedure of fitting occultation observations assuming a uniform brightness disk and then correcting the resulting diameter for limb darkening can give erroneous results. The dynamic effects cause Miras to appear larger and cooler than they actually are. A post-shock relaxation zone code developed by J. N. Pierce was modified and interfaced with the Bowen code to follow the ionization state and cooling radiation emitted by Hydrogen, Helium, and 23 metals in the models. Mg II emission data were used to prepare a light curve that is compared with Mg II light curves observed with the IUE satellite. The relaxation models show that the periodic passage of shocks through the atmosphere results in much lower concentrations of molecular hydrogen and higher ionization fractions

  12. Patterns in atmospheric carbonaceous aerosols in China: emission estimates and observed concentrations

    NASA Astrophysics Data System (ADS)

    Cui, H.; Mao, P.; Zhao, Y.; Nielsen, C. P.; Zhang, J.

    2015-03-01

    remote sites, attributed partly to weaker atmospheric oxidation and SOC formation compared to summer. Enhanced SOC formation from oxidization and anthropogenic activities like biomass combustion is judged to have crucial effects on severe haze events characterized by high particle concentrations. Several observational studies indicate an increasing trend in ambient OC/EC (but not in OC or EC individually) from 2000 to 2010, confirming increased atmospheric oxidation of OC across the country. Combining the results of emission estimation and observations, the improvement over prior emission inventories is indicated by inter-annual comparisons and correlation analysis. It is also indicated, however, that the estimated growth in emissions might be faster than observed growth, and that some sources with high primary OC/EC like burning of biomass are still underestimated. Further studies to determine changing emission factors over time in the residential sector and to compare to other measurements such as satellite observations are thus suggested to improve understanding of the levels and trends of primary carbonaceous aerosol emissions in China.

  13. Atmospheric constraints on the methane emissions from the East Siberian Shelf

    NASA Astrophysics Data System (ADS)

    Berchet, A.; Bousquet, P.; Pison, I.; Locatelli, R.; Chevallier, F.; Paris, J.-D.; Dlugokencky, E. J.; Laurila, T.; Hatakka, J.; Viisanen, Y.; Worthy, D. E. J.; Nisbet, E. G.; Fisher, R. E.; France, J. L.; Lowry, D.; Ivakhov, V.

    2015-09-01

    Sub-sea permafrost and hydrates in the East Siberian Arctic Ocean Continental Shelf (ESAS) constitute a substantial carbon pool, and a potentially large source of methane to the atmosphere. Previous studies based on interpolated oceanographic campaigns estimated atmospheric emissions from this area at 8-17 Tg CH4 y-1. Here, we propose insights based on atmospheric observations to evaluate these estimates. Isotopic observations suggest a biogenic origin (either terrestrial or marine) of the methane in air masses originating from ESAS during summer 2010. The comparison of high-resolution simulations of atmospheric methane mole fractions to continuous methane observations during the entire year 2012 confirms the high variability and heterogeneity of the methane releases from ESAS. Simulated mole fractions including a 8 Tg CH4 y-1 source from ESAS are found largely overestimated compared to the observations in winter, whereas summer signals are more consistent with each other. Based on a comprehensive statistical analysis of the observations and of the simulations, annual methane emissions from ESAS are estimated in a range of 0.5-4.3 Tg CH4 y-1.

  14. Atmospheric mercury emissions from mine wastes and surrounding geologically enriched terrains

    USGS Publications Warehouse

    Gustin, M.S.; Coolbaugh, M.F.; Engle, M.A.; Fitzgerald, B.C.; Keislar, R.E.; Lindberg, S.E.; Nacht, D.M.; Quashnick, J.; Rytuba, J.J.; Sladek, C.; Zhang, H.; Zehner, R.E.

    2003-01-01

    Waste rock and ore associated with Hg, precious and base metal mining, and their surrounding host rocks are typically enriched in mercury relative to natural background concentrations (<0.1 ??g Hg g-1). Mercury fluxes to the atmosphere from mineralized areas can range from background rates (0-15 ng m-2 h-1) to tens of thousands of ng m-2 h-1. Mercury enriched substrate constitutes a long-term source of mercury to the global atmospheric mercury pool. Mercury emissions from substrate are influenced by light, temperature, precipitation, and substrate mercury concentration, and occur during the day and night. Light-enhanced emissions are driven by two processes: desorption of elemental mercury accumulated at the soil:air interface, and photo reduction of mercury containing phases. To determine the need for and effectiveness of regulatory controls on short-lived anthropogenic point sources the contribution of mercury from geologic non-point sources to the atmospheric mercury pool needs to be quantified. The atmospheric mercury contribution from small areas of mining disturbance with relatively high mercury concentrations are, in general, less than that from surrounding large areas of low levels of mercury enrichment. In the arid to semi-arid west-ern United States volatilization is the primary means by which mercury is released from enriched sites.

  15. Urban scale atmospheric inversion of CO2 emissions using a high-density surface tower network over Indianapolis area

    NASA Astrophysics Data System (ADS)

    Lauvaux, T.; Miles, N. L.; Richardson, S.; Davis, K. J.; Deng, A.; Hardesty, R. M.; Shepson, P. B.; Cambaliza, M. L.; Iraci, L. T.; Hillyard, P. W.; Gurney, K. R.; Karion, A.; Mcgowan, L. E.; Possolo, A.; Razlivanov, I. N.; Sarmiento, D.; Sweeney, C.; Turnbull, J. C.; Whetstone, J. R.

    2013-12-01

    Greenhouse Gas emissions from urban areas represent a significant fraction of the overall release of fossil fuel CO2 from the surface of the globe into the atmosphere. Several ongoing efforts attempt to quantify these emissions over a few major cities across the world (i.e. Indianapolis, Los Angeles, Paris, London, Salt Lake City,...) and demonstrate the concept of atmospheric monitoring of city emissions. The accuracy of the method will highly depend on the inverse modeling framework. The atmospheric transport model and the probabilities assumed in the a priori will be used to extract the information content of surface emissions at very fine scales. But incorrect assumptions in the background emissions and concentrations or systematic errors in the local dynamics can generate artificial trends and seasonal variability in the local emissions. The construction of unbiased atmospheric modeling systems and well-defined prior errors remains a critical step in atmospheric emissions monitoring over urban areas. We present here the first inverse emission estimates over Indianapolis using a high-density surface tower network of CO2 analyzers. In order to minimize transport model errors, we developed a WRF-Chem-FDDA modeling system ingesting surface and profile measurements of horizontal mean wind, temperature and moisture in addition to the original CO2 emissions and boundary conditions. The systematic improvement of the simulated atmospheric conditions thanks to the nudging system is critical to identify and retrieve source locations at high resolution over the area. We then present an ensemble of inverse fluxes generated from varying the configuration of the inverse system in order to more accurately represent the probability space, exploring the assumptions in the a priori (i.e. the prior local urban emissions and the background atmospheric concentrations). We finally discuss the detection of trends or changes in the spatial distribution of sources at decadal time

  16. Influence of Fossil Fuel Emissions on CO2 Flux Estimation by Atmospheric Inversions

    NASA Astrophysics Data System (ADS)

    Saeki, T.; Patra, P. K.; van der Laan-Luijkx, I. T.; Peters, W.

    2015-12-01

    Top-down approaches (or atmospheric inversions) using atmospheric transport models with CO2 observations are an effective way to estimate carbon fluxes at global and regional scales. CO2 flux estimation by Bayesian inversions require a priori knowledge of terrestrial biosphere and oceanic fluxes and fossil fuel (FF) CO2 emissions. In most inversion frameworks, FF CO2 is assumed to be a known quantity because FF CO2 based on world statistics are thought to be more reliable than natural CO2 fluxes. However different databases of FF CO2 emissions may have different temporal and spatial variations especially at locations where statistics are not so accurate. In this study, we use 3 datasets of fossil fuel emissions in inversion estimations and evaluate the sensitivity of the optimized CO2 fluxes to FF emissions with two different inverse models, JAMSTEC's ACTM and CarbonTracker Europe (CTE). Interannually varying a priori FF CO2 emissions were based on 1) CDIAC database, 2) EDGARv4.2 database, and 3) IEA database, with some modifications. Biosphere and oceanic fluxes were optimized. Except for FF emissions, other conditions were kept the same in our inverse experiments. The three a priori FF emissions showed ~5% (~0.3GtC/yr) differences in their global total emissions in the early 2000's and the differences reached ~9% (~0.9 GtC/yr) in 2010. This resulted in 0.5-1 GtC/yr (2001-2011) and 0.3-0.6 GtC/yr (2007-2011) differences in the estimated global total emissions for the ACTM and CTE inversions, respectively. Regional differences in the FF emissions were relatively large in East Asia (~0.5 GtC/yr for ACTM and ~0.3 GtC/yr for CTE) and Europe (~0.3 GtC/yr for ACTM). These a priori flux differences caused differences in the estimated biosphere fluxes for ACTM in East Asia and Europe and also their neighboring regions such as West Asia, Boreal Eurasia, and North Africa. The main differences in the biosphere fluxes for CTE were found in Asia and the Americas.

  17. Model assessment of atmospheric pollution control schemes for critical emission regions

    NASA Astrophysics Data System (ADS)

    Zhai, Shixian; An, Xingqin; Liu, Zhao; Sun, Zhaobin; Hou, Qing

    2016-01-01

    In recent years, the atmospheric environment in portions of China has become significantly degraded and the need for emission controls has become urgent. Because more international events are being planned, it is important to implement air quality assurance targeted at significant events held over specific periods of time. This study sets Yanqihu (YQH), Beijing, the location of the 2014 Beijing APEC (Asia-Pacific Economic Cooperation) summit, as the target region. By using the atmospheric inversion model FLEXPART, we determined the sensitive source zones that had the greatest impact on the air quality of the YQH region in November 2012. We then used the air-quality model Models-3/CMAQ and a high-resolution emissions inventory of the Beijing-Tianjian-Hebei region to establish emission reduction tests for the entire source area and for specific sensitive source zones. This was achieved by initiating emission reduction schemes at different ratios and different times. The results showed that initiating a moderate reduction of emissions days prior to a potential event is more beneficial to the air quality of Beijing than initiating a high-strength reduction campaign on the day of the event. The sensitive source zone of Beijing (BJ-Sens) accounts for 54.2% of the total source area of Beijing (BJ), but its reduction effect reaches 89%-100% of the total area, with a reduction efficiency 1.6-1.9 times greater than that of the entire area. The sensitive source zone of Huabei (HuaB-Sens.) only represents 17.6% of the total area of Huabei (HuaB), but its emission reduction effect reaches 59%-97% of the entire area, with a reduction efficiency 4.2-5.5 times greater than that of the total area. The earlier that emission reduction measures are implemented, the greater the effect they have on preventing the transmission of pollutants. In addition, expanding the controlling areas to sensitive provinces and cities around Beijing (HuaB-sens) can significantly accelerate the reduction

  18. Methane emission by termites: Impacts on the self-cleansing mechanisms of the atmosphere

    SciTech Connect

    Mugedo, J.Z.A.

    1996-12-31

    Termites are reported to emit large quantities of methane, carbon dioxide, carbon monoxide, hydrogen and dimethyl sulfide. The emission of other trace gases, namely C{sub 2} to C{sub 10} hydrocarbons, is also documented. We have carried out, both in the field and in the laboratory, measurements of methane emissions by Macrotermes subhyalinus (Macrotermitinae), Trinervitermes bettonianus (Termitinae), and unidentified Cubitermes and Microcerotermes species. Measured CH{sub 4} field flux rates ranged from 3.66 to 98.25g per m{sup 2} of termite mound per year. Laboratory measurements gave emission rates that ranged from 14.61 to 165.05 mg CH{sub 4} per termite per year. Gaseous production in all species sampled varied both within species and from species to species. Recalculated global emission of methane from termites was found to be 14.0 x 10{sup 12} g CH{sub 4}, per year. From our study, termites contribution to atmospheric methane content is between 1.11% and 4.25% per year. This study discusses the greenhouse effects as well as photochemical disposal of methane in the lower atmosphere in the tropics and the impacts on the chemistry of HO{sub x} systems and CL{sub x} cycles.

  19. Oxygen emission line properties from analysis of MAVEN-IUVS Echellograms of the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Mayyasi, Majd A.; Clarke, John T.; Stewart, Ian; McClintock, William; Schneider, Nicholas M.; Jakosky, Bruce; IUVS Team

    2016-10-01

    The high resolution echelle mode of the Mars Atmosphere and Volatile Evolution (MAVEN) mission Imaging Ultraviolet Spectrograph (IUVS) instrument has been used to spectrally image the sunlit limb of Mars during the spacecraft periapse orbital segments. When multiple images are co-added over a few hours, there are detectable spectral emission features that have been identified to originate from atomic and molecular neutral species such as H, D, N, O, CO as well as from C+ ions. The echelle detector has a localized spectral resolution of ~0.008 Angstrom and is therefore capable of spectrally resolving the oxygen resonant triplet (130.217, 130.486 and 130.603 nm) and forbidden doublet (135.560 and 135.851 nm) emission lines. The brightness of each of these emission lines has been determined and will be compared with detected brightnesses of other species. The emission line integrated brightness ratios are being analyzed for insights into the abundance, excitation, and variability of oxygen in the martian atmosphere.

  20. Ultraviolet and Extreme-Ultraviolet Emissions at the Flare Footpoints Observed by Atmosphere Imaging Assembly

    NASA Technical Reports Server (NTRS)

    Qiu, Jiong; Sturrock, Zoe; Longcope, Dana W.; Klimchuk, James A.; Liu, Wen-Juan

    2013-01-01

    A solar flare is composed of impulsive energy release events by magnetic reconnection, which forms and heats flare loops. Recent studies have revealed a two-phase evolution pattern of UV 1600 A emission at the feet of these loops: a rapid pulse lasting for a few seconds to a few minutes, followed by a gradual decay on timescales of a few tens of minutes. Multiple band EUV observations by the Atmosphere Imaging Assembly further reveal very similar signatures. These two phases represent different but related signatures of an impulsive energy release in the corona. The rapid pulse is an immediate response of the lower atmosphere to an intense thermal conduction flux resulting from the sudden heating of the corona to high temperatures (we rule out energetic particles due to a lack of significant hard X-ray emission). The gradual phase is associated with the cooling of hot plasma that has been evaporated into the corona. The observed footpoint emission is again powered by thermal conduction (and enthalpy), but now during a period when approximate steady-state conditions are established in the loop. UV and EUV light curves of individual pixels may therefore be separated into contributions from two distinct physical mechanisms to shed light on the nature of energy transport in a flare.We demonstrate this technique using coordinated, spatially resolved observations of UV and EUV emissions from the footpoints of a C3.2 thermal flare.

  1. ULTRAVIOLET AND EXTREME-ULTRAVIOLET EMISSIONS AT THE FLARE FOOTPOINTS OBSERVED BY ATMOSPHERE IMAGING ASSEMBLY

    SciTech Connect

    Qiu Jiong; Longcope, Dana W.; Liu Wenjuan; Sturrock, Zoe; Klimchuk, James A.

    2013-09-01

    A solar flare is composed of impulsive energy release events by magnetic reconnection, which forms and heats flare loops. Recent studies have revealed a two-phase evolution pattern of UV 1600 A emission at the feet of these loops: a rapid pulse lasting for a few seconds to a few minutes, followed by a gradual decay on timescales of a few tens of minutes. Multiple band EUV observations by the Atmosphere Imaging Assembly further reveal very similar signatures. These two phases represent different but related signatures of an impulsive energy release in the corona. The rapid pulse is an immediate response of the lower atmosphere to an intense thermal conduction flux resulting from the sudden heating of the corona to high temperatures (we rule out energetic particles due to a lack of significant hard X-ray emission). The gradual phase is associated with the cooling of hot plasma that has been evaporated into the corona. The observed footpoint emission is again powered by thermal conduction (and enthalpy), but now during a period when approximate steady-state conditions are established in the loop. UV and EUV light curves of individual pixels may therefore be separated into contributions from two distinct physical mechanisms to shed light on the nature of energy transport in a flare. We demonstrate this technique using coordinated, spatially resolved observations of UV and EUV emissions from the footpoints of a C3.2 thermal flare.

  2. Oxygen 1.27 micron emission from the atmosphere of Venus

    NASA Astrophysics Data System (ADS)

    Parisot, J.-P.; Moreels, G.

    1980-04-01

    The emission of O2 in the 1 Delta g band at 1.27 micron originating from the upper atmosphere of Venus is computed. Seven different production mechanisms are compared. The adopted value for the quenching rate coefficient is 3 x 10 to the -20th cu cm/sec. The results are compared with the measurements of Connes (1978) and it is shown that the values of the ozone profile calculated by Sze and McElroy (1975) are too low to explain the emission at 1.27 micron on the basis of the ozone photolysis. In this case, the ozone quantity would be underestimated by a factor of at least 10. The scarcity of kinetic data relative to the other processes, which involve ClO for example, does not allow a reliable identification of the main process responsible for the emission.

  3. Green light emission from terbium doped silicon rich silicon oxide films obtained by plasma enhanced chemical vapor deposition.

    PubMed

    Podhorodecki, A; Zatryb, G; Misiewicz, J; Wojcik, J; Wilson, P R J; Mascher, P

    2012-11-30

    The effect of silicon concentration and annealing temperature on terbium luminescence was investigated for thin silicon rich silicon oxide films. The structures were deposited by means of plasma enhanced chemical vapor deposition. The structural properties of these films were investigated by Rutherford backscattering spectrometry, transmission electron microscopy and Raman scattering. The optical properties were investigated by means of photoluminescence and photoluminescence decay spectroscopy. It was found that both the silicon concentration in the film and the annealing temperature have a strong impact on the terbium emission intensity. In this paper, we present a detailed discussion of these issues and determine the optimal silicon concentration and annealing temperature.

  4. Green light emission from terbium doped silicon rich silicon oxide films obtained by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Podhorodecki, A.; Zatryb, G.; Misiewicz, J.; Wojcik, J.; Wilson, P. R. J.; Mascher, P.

    2012-11-01

    The effect of silicon concentration and annealing temperature on terbium luminescence was investigated for thin silicon rich silicon oxide films. The structures were deposited by means of plasma enhanced chemical vapor deposition. The structural properties of these films were investigated by Rutherford backscattering spectrometry, transmission electron microscopy and Raman scattering. The optical properties were investigated by means of photoluminescence and photoluminescence decay spectroscopy. It was found that both the silicon concentration in the film and the annealing temperature have a strong impact on the terbium emission intensity. In this paper, we present a detailed discussion of these issues and determine the optimal silicon concentration and annealing temperature.

  5. Different mechanism of two-proton emission from proton-rich nuclei 23Al and 22Mg

    NASA Astrophysics Data System (ADS)

    Ma, Y. G.; Fang, D. Q.; Sun, X. Y.; Zhou, P.; Togano, Y.; Aoi, N.; Baba, H.; Cai, X. Z.; Cao, X. G.; Chen, J. G.; Fu, Y.; Guo, W.; Hara, Y.; Honda, T.; Hu, Z. G.; Ieki, K.; Ishibashi, Y.; Ito, Y.; Iwasa, N.; Kanno, S.; Kawabata, T.; Kimura, H.; Kondo, Y.; Kurita, K.; Kurokawa, M.; Moriguchi, T.; Murakami, H.; Ooishi, H.; Okada, K.; Ota, S.; Ozawa, A.; Sakurai, H.; Shimoura, S.; Shioda, R.; Takeshita, E.; Takeuchi, S.; Tian, W. D.; Wang, H. W.; Wang, J. S.; Wang, M.; Yamada, K.; Yamada, Y.; Yasuda, Y.; Yoneda, K.; Zhang, G. Q.; Motobayashi, T.

    2015-04-01

    Two-proton relative momentum (qpp) and opening angle (θpp) distributions from the three-body decay of two excited proton-rich nuclei, namely 23Al → p + p +21Na and 22Mg → p + p +20Ne, have been measured with the projectile fragment separator (RIPS) at the RIKEN RI Beam Factory. An evident peak at qpp ∼ 20 MeV / c as well as a peak in θpp around 30° are seen in the two-proton break-up channel from a highly-excited 22Mg. In contrast, such peaks are absent for the 23Al case. It is concluded that the two-proton emission mechanism of excited 22Mg is quite different from the 23Al case, with the former having a favorable diproton emission component at a highly excited state and the latter dominated by the sequential decay process.

  6. An attempt at estimating Paris area CO2 emissions from atmospheric concentration measurements

    NASA Astrophysics Data System (ADS)

    Bréon, F. M.; Broquet, G.; Puygrenier, V.; Chevallier, F.; Xueref-Remy, I.; Ramonet, M.; Dieudonné, E.; Lopez, M.; Schmidt, M.; Perrussel, O.; Ciais, P.

    2015-02-01

    Atmospheric concentration measurements are used to adjust the daily to monthly budget of fossil fuel CO2 emissions of the Paris urban area from the prior estimates established by the Airparif local air quality agency. Five atmospheric monitoring sites are available, including one at the top of the Eiffel Tower. The atmospheric inversion is based on a Bayesian approach, and relies on an atmospheric transport model with a spatial resolution of 2 km with boundary conditions from a global coarse grid transport model. The inversion adjusts prior knowledge about the anthropogenic and biogenic CO2 fluxes from the Airparif inventory and an ecosystem model, respectively, with corrections at a temporal resolution of 6 h, while keeping the spatial distribution from the emission inventory. These corrections are based on assumptions regarding the temporal autocorrelation of prior emissions uncertainties within the daily cycle, and from day to day. The comparison of the measurements against the atmospheric transport simulation driven by the a priori CO2 surface fluxes shows significant differences upwind of the Paris urban area, which suggests a large and uncertain contribution from distant sources and sinks to the CO2 concentration variability. This contribution advocates that the inversion should aim at minimising model-data misfits in upwind-downwind gradients rather than misfits in mole fractions at individual sites. Another conclusion of the direct model-measurement comparison is that the CO2 variability at the top of the Eiffel Tower is large and poorly represented by the model for most wind speeds and directions. The model's inability to reproduce the CO2 variability at the heart of the city makes such measurements ill-suited for the inversion. This and the need to constrain the budgets for the whole city suggests the assimilation of upwind-downwind mole fraction gradients between sites at the edge of the urban area only. The inversion significantly improves the agreement

  7. Reducing Uncertainty in Life Cycle CH4 Emissions from Natural Gas using Atmospheric Inversions

    NASA Astrophysics Data System (ADS)

    Schwietzke, S.; Griffin, W.; Matthews, S.

    2012-12-01

    Methane emissions associated with the production and use of natural gas (NG) are highly uncertain because of challenges to accurately measure fugitive CH4 emissions from NG leaks and venting throughout a large and complex industry. Better understanding the CH4 emissions from the NG life cycle is important for two reasons. First, the rising interest in NG use associated with the recent development of unconventional sources, such as shale gas, may cause a shift in the future energy system from coal towards more NG. Given its relatively high greenhouse gas potency, fugitive CH4 emissions from the NG life cycle have the potential to outweigh lower CO2 emissions compared to coal use in terms of their climate impacts over the next few decades. Second, worldwide NG related CH4 emissions play a key role in understanding the global CH4 budget. According to current atmospheric inversion studies, NG and oil production account for about 12% of global CH4 emissions. However, these results largely depend on prior emissions estimates whose uncertainties are poorly documented. The objective of this research is to analyze which ranges of global fugitive CH4 emissions from the NG life cycle are reasonable given atmospheric observations as a constraint. We establish a prior global CH4 inventory for NG, oil, and coal using emissions data from the life cycle assessment (LCA) literature. This inventory includes uncertainty estimates for different fuels, world regions, and time periods based on LCA literature, which existing inventories do not account for. Furthermore, global CH4 inversion modeling will be used to test bottom-up hypotheses of high NG leakage and venting associated with the upper bound of the prior inventory. Given the use of detailed LCA emissions factors, we will test bottom-up scenarios regarding management and technology improvements over time. The emissions inventory will be established for the past decade, and inversion modeling will be carried out using NOAA

  8. Patterns in atmospheric carbonaceous aerosols in China: emission estimates and observed concentrations

    NASA Astrophysics Data System (ADS)

    Cui, H.; Mao, P.; Zhao, Y.; Nielsen, C. P.; Zhang, J.

    2015-08-01

    , attributed partly to weaker atmospheric oxidation and SOC formation compared to summer. Enhanced SOC formation from oxidization and anthropogenic activities like biomass combustion is judged to have crucial effects on severe haze events characterized by high particle concentrations. Several observational studies indicate an increasing trend in ambient OC / EC (but not in OC or EC individually) from 2000 to 2010, confirming increased atmospheric oxidation of OC across the country. Combining the results of emission estimation and observations, the improvement over prior emission inventories is indicated by inter-annual comparisons and correlation analysis. It is also indicated, however, that the estimated growth in emissions might be faster than observed growth, and that some sources with high primary OC / EC, such as burning of biomass, are still underestimated. Further studies to determine changing EFs over time in the residential sector and to compare to other measurements, such as satellite observations, are thus suggested to improve understanding of the levels and trends of primary carbonaceous aerosol emissions in China.

  9. Transboundary Atmospheric Pollution of Oil-Gas Industry Emissions from North Caspian region of Kazakhstan

    NASA Astrophysics Data System (ADS)

    Zakarin, E.; Balakay, L.; Mirkarimova, B.; Mahura, A.; Baklanov, A.; Sorensen, J. H.

    2012-04-01

    The Atyraus region (Republic of Kazahstan) is occupied with more than 60 oil-gas fields which are actively developing. Moreover, a new world largest field so-called Kashagan has been discovered on the Caspian Sea shelf and its exploitation is planned by the end of 2012. In our study, this region has been selected as a source region of sulphates emissions accounting about 15 tons (2009 estimates). Three locations have been chosen in the region covering adjacent Caspian Sea aquatoria, and emissions were equally distributed among these locations (with an emission rate of 4.72*10-4 kg/sec). From original sulphates emissions between 46-82% are subjected to atmospheric transport away from the sources. Releases were considered to be continuous. The long-term modelling of atmospheric transport, dispersion and deposition of sulphates was done employing the Lagrangian type model called DERMA, run at the NEC SX6 supercomputing facilities. After each day of release the atmospheric transport has been tracked for the next 2 week period. Input meteorological 3D fields were obtained from the ECMWF data archives. The generated output included air concentration (at model levels), time integrated air concentration, dry and wet deposition (at the surface). The results of dispersion modelling had been post-processed and integrated into GIS environment (using ArcGIS). These have been further used to calculate annual averaged and summary concentration and deposition fields for administrative regions, counties and cities of Kazakhstan, as well as territories of the neighboring countries. It has been found that on an annual scale, the dominating atmospheric transport of pollution from the Atyraus region is toward east and north-east, mostly due to prevailing westerlies. Although on a hemispheric scale, the wet deposition dominates over dry (63 vs. 37%), for Kazakhstan the wet deposition contribution is slightly larger (65%). For Turkmenistan, dry deposition is almost twice higher compared

  10. Atmospheric emissions of typical toxic heavy metals from open burning of municipal solid waste in China

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Cheng, Ke; Wu, Weidong; Tian, Hezhong; Yi, Peng; Zhi, Guorui; Fan, Jing; Liu, Shuhan

    2017-03-01

    Municipal solid waste (MSW) contains considerable hazardous components and the widely-distributed open MSW burning in heavily-populated urban areas can cause direct exposure of hazardous materials to citizens. By determining the best available representation of composition-varying and time-varying emission factors with fuzzy mathematics method and S-shape curves, a comprehensive atmospheric emission inventories of 9 typical toxic heavy metals (THMs, e.g. mercury (Hg), arsenic (As), lead (Pb), cadmium (Cd), chromium (Cr), selenium (Se), copper (Cu), zinc (Zn), and nickel (Ni)) from open MSW burning activities in China is established during the period of 2000-2013 for the first time. Further, the emissions in 2013 are allocated at a high spatial resolution of 0.5° × 0.5° grid by surrogate indexes. The results show that 9 typical THMs emissions from open MSW burning are estimated at 21.25 t for Hg, 131.52 t for As, 97.12 t for Pb, 10.12 t for Cd, 50.58 t for Cr, 81.95 t for Se, 382.42 t for Cu, 1790.70 t for Zn, and 43.50 t for Ni, respectively. In terms of spatial variation, the majority of emissions are concentrated in relatively developed and densely-populated regions, especially for the eastern, central and southern regions. Moreover, future emissions are also projected for the period of 2015-2030 based on different scenarios of the independent and collaborative effects of control proposals including minimizing waste, improving MSW incineration ratio, and enhancing waste sorting and recycling, etc. The collaborative effect of the above proposals is expected to bring the most effective reduction to THMs emissions from open MSW burning in China except for Hg. The results will be supplementary to all anthropogenic emissions and useful for relevant policy-making and the improvement of urban air quality as well as human health.

  11. Ammonia emissions from an anaerobic digestion plant estimated using atmospheric measurements and dispersion modelling.

    PubMed

    Bell, Michael W; Tang, Y Sim; Dragosits, Ulrike; Flechard, Chris R; Ward, Paul; Braban, Christine F

    2016-10-01

    Anaerobic digestion (AD) is becoming increasingly implemented within organic waste treatment operations. The storage and processing of large volumes of organic wastes through AD has been identified as a significant source of ammonia (NH3) emissions, however the totality of ammonia emissions from an AD plant have not been previously quantified. The emissions from an AD plant processing food waste were estimated through integrating ambient NH3 concentration measurements, atmospheric dispersion modelling, and comparison with published emission factors (EFs). Two dispersion models (ADMS and a backwards Lagrangian stochastic (bLS) model) were applied to calculate emission estimates. The bLS model (WindTrax) was used to back-calculate a total (top-down) emission rate for the AD plant from a point of continuous NH3 measurement downwind from the plant. The back-calculated emission rates were then input to the ADMS forward dispersion model to make predictions of air NH3 concentrations around the site, and evaluated against weekly passive sampler NH3 measurements. As an alternative approach emission rates from individual sources within the plant were initially estimated by applying literature EFs to the available site parameters concerning the chemical composition of waste materials, room air concentrations, ventilation rates, etc. The individual emission rates were input to ADMS and later tuned by fitting the simulated ambient concentrations to the observed (passive sampler) concentration field, which gave an excellent match to measurements after an iterative process. The total emission from the AD plant thus estimated by a bottom-up approach was 16.8±1.8mgs(-1), which was significantly higher than the back-calculated top-down estimate (7.4±0.78mgs(-1)). The bottom-up approach offered a more realistic treatment of the source distribution within the plant area, while the complexity of the site was not ideally suited to the bLS method, thus the bottom-up method is believed

  12. Emission of polycyclic aromatic hydrocarbons and their carcinogenic potencies from cooking sources to the urban atmosphere.

    PubMed Central

    Li, Chun-The; Lin, Yuan-Chung; Lee, Wen-Jhy; Tsai, Perng-Jy

    2003-01-01

    Traffic has long been recognized as the major contributor to polycyclic aromatic hydrocarbon (PAH) concentrations. However, this does not consider the contribution of cooking sources of PAHs. This study set out, first, to assess the characteristics of PAHs and their corresponding benzo[a]pyrene equivalent (B[a]Peq) emissions from cooking sources to the urban atmosphere. To illustrate the importance of cooking sources, PAH emissions from traffic sources were then calculated and compared. The entire study was conducted on a city located in southern Taiwan. PAH samples were collected from the exhaust stacks of four types of restaurant: Chinese, Western, fast food, and Japanese. For total PAHs, results show that the fractions of gaseous PAHs (range, 75.9-89.9%) were consistently higher than the fractions of particulate PAHs (range, 10.1-24.1%) in emissions from the four types of restaurant. But for total B[a]Peq, we found that the contributions of gaseous PAHs (range, 15.7-21.9%) were consistently lower than the contributions of particulate PAHs (range, 78.1-84.3%). For emission rates of both total PAHs and total B[a]Peq, a consistent trend was found for the four types of restaurant: Chinese (2,038 and 154 kg/year, respectively) > Western (258 and 20.4 kg/year, respectively) > fast food (31.4 and 0.104 kg/year, respectively) > Japanese (5.11 and 0.014 kg/year, respectively). By directly adapting the emission data obtained from Chinese restaurants, we found that emission rates on total PAHs and total B[a]Peq for home kitchen sources were 6,639 and 501 kg/year, respectively. By combining both restaurant sources and home kitchen sources, this study yielded emission rates of total PAHs and total B[a]Peq from cooking sources of the studied city of 8,973 and 675 kg/year, respectively. Compared with PAH emissions from traffic sources in the same city, we found that although the emission rates of total PAHs for cooking sources were significantly less than those for traffic

  13. Atmospheric observations and emissions estimates of methane and nitrous oxide from regional to global scale

    NASA Astrophysics Data System (ADS)

    Kort, Eric Adam

    2011-12-01

    Methane (CH4) and Nitrous Oxide (N2O) are the two most significant anthropogenic, long-lived, non-CO2 greenhouse gases, together perturbing the earth's energy balance by an amount comparable to that of CO2. This dissertation will focus on the use of atmospheric observations to quantify emissions of CH4 and N2O. First top-down emissions constraints on the regional scale, covering large areas of the U.S and southern Canada, are derived from airborne observations made in Spring of 2003. Using a receptor-oriented Lagrangian particle dispersion model provides robust validation of bottom-up emission estimates from EDGAR 32FT2000 and GEIA inventories. It is found that EDGAR CH4 emission rates are slightly low by a factor of 1.08 +/- 0.15 (2 sigma), while both EDGAR and GEIA N2O emissions are significantly too low, by factors of 2.62 +/- 0.50 and 3.05 +/- 0.61 respectively. This analysis is then extended over a full calendar year in 2004 with observations from NOAA's tall tower and aircraft profile network. EDGAR 32FT2000 CH 4 emissions are found to be consistent with observations, though the newer EDGAR v4.0 reduces CH4 emissions by 30%, and this reduction is not consistent with this study. Scaling factors found for N2O in May/June of 2003 (2.62 & 3.05) are found to hold for February-May of 2004, suggesting inventories are significantly too low in primary growing season coincident with significant fertilizer inputs. A new instrument for airborne observation of CO2, CH 4, N2O, and CO is introduced, and its operation and in-field performance are highlighted (demonstrated 1-sec precisions of 20 ppb, 0.5 ppb, 0.09 ppb, and 0.15 ppb respectively). Finally, global N2O observations collected with this sensor on the HIPPO (Hlaper Pole to Pole Observations) campaign are assessed. Comparison with a global model and subsequent inversion indicates strong, episodic inputs of nitrous oxide from tropical regions are necessary to bring observations and model in agreement. Findings

  14. Enhanced light emission from Si nanocrystals produced using SiOx/SiO2 multilayered silicon-rich oxides

    NASA Astrophysics Data System (ADS)

    Yoon, Jong-Hwan

    2015-07-01

    The light emission from Si nanocrystals (NCs) produced in SiO2 by annealing of SiOx/SiO2 multilayered silicon-rich oxide (SRO) is examined as a function of the SiOx layer thickness. Multilayered SRO structures are shown to produce a significant increase in emission intensities with a large redshift of spectra as compared with a single-layer SRO film. A multilayered SRO film with ∼6-nm thick SiO1.45 layers exhibits a 13-fold increase in the emission intensity with a redshift of ∼70 nm relative to a single-layer SiO1.45 SRO film with a thickness equivalent to the total SiO1.45 layer thickness in the multilayered film. The transmission electron microscopy analyses indicate that the enhancement of the emission intensity with the redshift of spectrum is caused by the enhanced aggregation of phase separated Si atoms in the former SiOx layers due to the hindering of interlayer diffusion of Si by the neighboring SiO2 layers.

  15. Control strategies of atmospheric mercury emissions from coal-fired power plants in China.

    PubMed

    Tian, Hezhong; Wang, Yan; Cheng, Ke; Qu, Yiping; Hao, Jiming; Xue, Zhigang; Chai, Fahe

    2012-05-01

    Atmospheric mercury (Hg) emission from coal is one of the primary sources of anthropogenic discharge and pollution. China is one of the few countries in the world whose coal consumption constitutes about 70% of total primary energy, and over half of coals are burned directly for electricity generation. Atmospheric emissions of Hg and its speciation from coal-fired power plants are of great concern owing to their negative impacts on regional human health and ecosystem risks, as well as long-distance transport. In this paper, recent trends of atmospheric Hg emissions and its species split from coal-fired power plants in China during the period of 2000-2007 are evaluated, by integrating each plant's coal consumption and emission factors, which are classified by different subcategories of boilers, particulate matter (PM) and sulfur dioxide (SO2) control devices. Our results show that the total Hg emissions from coal-fired power plants have begun to decrease from the peak value of 139.19 t in 2005 to 134.55 t in 2007, though coal consumption growing steadily from 1213.8 to 1532.4 Mt, which can be mainly attributed to the co-benefit Hg reduction by electrostatic precipitators/fabric filters (ESPs/FFs) and wet flue gas desulfurization (WFGD), especially the sharp growth in installation of WFGD both in the new and existing power plants since 2005. In the coming 12th five-year-plan, more and more plants will be mandated to install De-NO(x) (nitrogen oxides) systems (mainly selective catalytic reduction [SCR] and selective noncatalytic reduction [SNCR]) for minimizing NO(x) emission, thus the specific Hg emission rate per ton of coal will decline further owing to the much higher co-benefit removal efficiency by the combination of SCR + ESPs/FFs + WFGD systems. Consequently, SCR + ESPs/FFs + WFGD configuration will be the main path to abate Hg discharge from coal-fired power plants in China in the near future. However advanced specific Hg removal technologies are necessary

  16. Relating landfill gas emissions to atmospheric pressure using numerical modelling and state-space analysis.

    PubMed

    Poulsen, Tjalfe G; Christophersen, Mette; Moldrup, Per; Kjeldsen, Peter

    2003-08-01

    Landfill gas (CO2 and CH4) concentrations and fluxes in soil adjacent to an old, unlined Danish municipal landfill measured over a 48-hour period during the passage of a low-pressure weather system were used to identify processes governing gas fluxes and concentrations. Two different approaches were applied: (I) State-space analysis was used to identify relations between gas flux and short-term (hourly) variations in atmospheric pressure. (II) A numerical gas transport model was fitted to the data and used to quantify short-term impacts of variations in atmospheric pressure, volumetric soil-water content, soil gas permeability, soil gas diffusion coefficients, and biological CH4 degradation rate upon landfill gas concentration and fluxes in the soil. Fluxes and concentrations were found to be most sensitive to variations in volumetric soil water content, atmospheric pressure variations and gas permeability whereas variations in CH4 oxidation rate and molecular coefficients had less influence. Fluxes appeared to be most sensitive to atmospheric pressure at intermediate distances from the landfill edge. Also overall CH4 fluxes out of the soil over longer periods (years) were largest during periods with rapidly decreasing atmospheric pressures resulting in emission of large amounts of CH4 during short periods of time. This effect, however, was less significant for the CO2 fluxes.

  17. Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications

    PubMed Central

    Jokinen, Tuija; Berndt, Torsten; Makkonen, Risto; Kerminen, Veli-Matti; Junninen, Heikki; Stratmann, Frank; Herrmann, Hartmut; Guenther, Alex B.; Worsnop, Douglas R.; Kulmala, Markku; Ehn, Mikael; Sipilä, Mikko

    2015-01-01

    Oxidation products of monoterpenes and isoprene have a major influence on the global secondary organic aerosol (SOA) burden and the production of atmospheric nanoparticles and cloud condensation nuclei (CCN). Here, we investigate the formation of extremely low volatility organic compounds (ELVOC) from O3 and OH radical oxidation of several monoterpenes and isoprene in a series of laboratory experiments. We show that ELVOC from all precursors are formed within the first minute after the initial attack of an oxidant. We demonstrate that under atmospherically relevant concentrations, species with an endocyclic double bond efficiently produce ELVOC from ozonolysis, whereas the yields from OH radical-initiated reactions are smaller. If the double bond is exocyclic or the compound itself is acyclic, ozonolysis produces less ELVOC and the role of the OH radical-initiated ELVOC formation is increased. Isoprene oxidation produces marginal quantities of ELVOC regardless of the oxidant. Implementing our laboratory findings into a global modeling framework shows that biogenic SOA formation in general, and ELVOC in particular, play crucial roles in atmospheric CCN production. Monoterpene oxidation products enhance atmospheric new particle formation and growth in most continental regions, thereby increasing CCN concentrations, especially at high values of cloud supersaturation. Isoprene-derived SOA tends to suppress atmospheric new particle formation, yet it assists the growth of sub-CCN-size primary particles to CCN. Taking into account compound specific monoterpene emissions has a moderate effect on the modeled global CCN budget. PMID:26015574

  18. Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications.

    PubMed

    Jokinen, Tuija; Berndt, Torsten; Makkonen, Risto; Kerminen, Veli-Matti; Junninen, Heikki; Paasonen, Pauli; Stratmann, Frank; Herrmann, Hartmut; Guenther, Alex B; Worsnop, Douglas R; Kulmala, Markku; Ehn, Mikael; Sipilä, Mikko

    2015-06-09

    Oxidation products of monoterpenes and isoprene have a major influence on the global secondary organic aerosol (SOA) burden and the production of atmospheric nanoparticles and cloud condensation nuclei (CCN). Here, we investigate the formation of extremely low volatility organic compounds (ELVOC) from O3 and OH radical oxidation of several monoterpenes and isoprene in a series of laboratory experiments. We show that ELVOC from all precursors are formed within the first minute after the initial attack of an oxidant. We demonstrate that under atmospherically relevant concentrations, species with an endocyclic double bond efficiently produce ELVOC from ozonolysis, whereas the yields from OH radical-initiated reactions are smaller. If the double bond is exocyclic or the compound itself is acyclic, ozonolysis produces less ELVOC and the role of the OH radical-initiated ELVOC formation is increased. Isoprene oxidation produces marginal quantities of ELVOC regardless of the oxidant. Implementing our laboratory findings into a global modeling framework shows that biogenic SOA formation in general, and ELVOC in particular, play crucial roles in atmospheric CCN production. Monoterpene oxidation products enhance atmospheric new particle formation and growth in most continental regions, thereby increasing CCN concentrations, especially at high values of cloud supersaturation. Isoprene-derived SOA tends to suppress atmospheric new particle formation, yet it assists the growth of sub-CCN-size primary particles to CCN. Taking into account compound specific monoterpene emissions has a moderate effect on the modeled global CCN budget.

  19. What would dense atmospheric observation networks bring to the quantification of city CO2 emissions?

    NASA Astrophysics Data System (ADS)

    Wu, Lin; Broquet, Grégoire; Ciais, Philippe; Bellassen, Valentin; Vogel, Felix; Chevallier, Frédéric; Xueref-Remy, Irène; Wang, Yilong

    2016-06-01

    Cities currently covering only a very small portion ( < 3 %) of the world's land surface directly release to the atmosphere about 44 % of global energy-related CO2, but they are associated with 71-76 % of CO2 emissions from global final energy use. Although many cities have set voluntary climate plans, their CO2 emissions are not evaluated by the monitoring, reporting, and verification (MRV) procedures that play a key role for market- or policy-based mitigation actions. Here we analyze the potential of a monitoring tool that could support the development of such procedures at the city scale. It is based on an atmospheric inversion method that exploits inventory data and continuous atmospheric CO2 concentration measurements from a network of stations within and around cities to estimate city CO2 emissions. This monitoring tool is configured for the quantification of the total and sectoral CO2 emissions in the Paris metropolitan area (˜ 12 million inhabitants and 11.4 TgC emitted in 2010) during the month of January 2011. Its performances are evaluated in terms of uncertainty reduction based on observing system simulation experiments (OSSEs). They are analyzed as a function of the number of sampling sites (measuring at 25 m a.g.l.) and as a function of the network design. The instruments presently used to measure CO2 concentrations at research stations are expensive (typically ˜ EUR 50 k per sensor), which has limited the few current pilot city networks to around 10 sites. Larger theoretical networks are studied here to assess the potential benefit of hypothetical operational lower-cost sensors. The setup of our inversion system is based on a number of diagnostics and assumptions from previous city-scale inversion experiences with real data. We find that, given our assumptions underlying the configuration of the OSSEs, with 10 stations only the uncertainty for the total city CO2 emission during 1 month is significantly reduced by the inversion by ˜ 42 %. It can be

  20. Atmospheric Mercury in the Barnett Shale Area, Texas: Implications for Emissions from Oil and Gas Processing.

    PubMed

    Lan, Xin; Talbot, Robert; Laine, Patrick; Torres, Azucena; Lefer, Barry; Flynn, James

    2015-09-01

    Atmospheric mercury emissions in the Barnett Shale area were studied by employing both stationary measurements and mobile laboratory surveys. Stationary measurements near the Engle Mountain Lake showed that the median mixing ratio of total gaseous mercury (THg) was 138 ppqv (140 ± 29 ppqv for mean ± S.D.) during the June 2011 study period. A distinct diurnal variation pattern was observed in which the highest THg levels appeared near midnight, followed by a monotonic decrease until midafternoon. The influence of oil and gas (ONG) emissions was substantial in this area, as inferred from the i-pentane/n-pentane ratio (1.17). However, few THg plumes were captured by our mobile laboratory during a ∼3700 km survey with detailed downwind measurements from 50 ONG facilities. One compressor station and one natural gas condensate processing facility were found to have significant THg emissions, with maximum THg levels of 963 and 392 ppqv, respectively, and the emissions rates were estimated to be 7.9 kg/yr and 0.3 kg/yr, respectively. Our results suggest that the majority of ONG facilities in this area are not significant sources of THg; however, it is highly likely that a small number of these facilities contribute a relatively large amount of emissions in the ONG sector.

  1. Atmospheric Impact of Large Methane Emissions and the Gulf Oil Spill

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, S.; Cameron-Smith, P. J.; Bergmann, D. J.

    2010-12-01

    A vast quantity of a highly potent greenhouse gas, methane, is locked in the solid phase as methane clathrates in ocean sediments and underneath permafrost regions. Clathrates are ice-like deposits containing a mixture of water and gas (mostly methane) which are stable under high pressure and low temperatures. Current estimates are about 1600 - 2000 GtC present in oceans and about 400GtC in Arctic permafrost (Archer et al. 2009). This is about 4000 times that of current annual emissions. In a warming climate, increase in ocean temperatures could rapidly destabilize the geothermal gradient which in turn could lead to dissociation of the clathrates and release of methane into the ocean and subsequently into the atmosphere as well. This could result in a number of effects including strong greenhouse heating, increased surface ozone, reduced stratospheric ozone, and intensification of the Arctic ozone hole. Many of the effects in the chemistry of the atmosphere are non-linear. In this paper, we present a parametric study of the effect of large scale methane release to the atmosphere. To that end we use the CESM (Community Earth System Model) version 1 with fully active coupled atmosphere-ocean-land model together with super-fast atmospheric chemistry module to simulate the response to increasing CH4 by 2, 3, 10 and 100 times that of the present day. We have also conducted a parametric study of the possible impact of gaseous emissions from the oil spill in the Gulf of Mexico, which is a proxy for future clathrate releases. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  2. Ocean to Continent Transfer of Atmospheric Se: Emission, Sources and Fate as Revealed by Epiphytic Lichens

    NASA Astrophysics Data System (ADS)

    Wen, H.; Carignan, J.

    2005-12-01

    Because of the very narrow margin between nutritionally optimal and potentially toxic dietary exposures for animals and humans, selenium sources and fate in the environment is an important question. The major sources of atmospheric Se include diverse anthropogenic activities, natural emission of marine biogenic Se and punctual volcanic contributions. Lichens have been used to document elemental atmospheric deposition, including that of volatile elements such as Se, Hg, Sb, As, and to evaluate the natural and anthropogenic input in the atmosphere. Here we report the Cl and Se contents in lichens and various relationships for estimating atmospheric Se sources. Samples were collected in coastal and inland areas from United States (west coast), Canada (west coast and Hudson Bay) and France (west coast). Se and Cl concentrations in samples from coastal areas are well correlated to each other, suggesting the two elements would originate from the same source. Cl is mainly derived from marine sources as sea salts generated from the sea spray. Se is also naturally emitted to the atmosphere from the seawater as methylated Se compounds such as DMSe, DMDSe and MeSeH. Adsorption of cations on negatively charged organic films will probably not be effective for Se because it mainly occurs as anionic forms in seawater. Rather, volatile methylated Se compounds are directly released at the sea surface and later adsorbed on atmospheric particles, leading to Se enrichment relative to Cl and related to the gas-to-particle partitioning. This emission process would explain the fact that Se/Cl ratio measured in "coastal" lichens is higher than that of the bulk seawater by about 5 orders of magnitude. This ratio also seems geographically dependant. For similar Cl concentrations, lichens from southern Hudson Bay (Canada) have a higher Se/Cl ratio than that measured in lichens from California (USA); the lichens from France being intermediate. We suppose that this difference might be the

  3. Atmospheric trend and emission estimates for HFC-43-10mee (1999 to 2010)

    NASA Astrophysics Data System (ADS)

    Arnold, T.; Ivy, D. J.; Muhle, J.; Harth, C. M.; Salameh, P.; Weiss, R. F.

    2010-12-01

    We present the first atmospheric measurements of HFC-43-10mee (1,1,1,2,2,3,4,5,5,5-decafluoropentane), an anthropogenic gas introduced in the mid-1990s as a substitute for CFC-113 (1,1,2-trichlorotrifluoroethane). The global warming potential of this HFC (hydrofluorocarbon) has been reported as 1640 (100-year time horizon), hence, its inclusion within a class of chemicals in the Kyoto Protocol and now its consideration for addition in the Montreal Protocol. Commercial HFC-43-10mee is a mixture of two diastereomers; both detectable using the Medusa GC-MS cryogenic trapping system (Miller et al., 2008), and included in our calculations for total HFC-43-10mee concentration. Chen et al. [2010] recently reported that the diastereomers have identical lifetimes in the troposphere of ≈18 years. Our northern hemisphere (NH) tropospheric record spans from 1999 to present day, utilizing 12 archive samples together with recent in situ measurements from the Advanced Global Atmospheric Gases Experiment (AGAGE) program at Trinidad Head and La Jolla, California. Precisions of < 0.01 ppt (parts-per-trillion, dry air mole fraction) allow for observation of an accelerated rise from 0.04 ppt in 2000 (growth rate of 0.01 ppt/yr) to 0.10 ppt in 2005 (0.02 ppt/yr) and 0.21 ppt in 2010 (0.03 ppt/yr). From the experimentally defined mole fractions in the background NH, we estimate the growth trend in the southern hemisphere using a simple box model which includes the stratosphere. Further, we estimate ‘top-down’ emissions to the global atmosphere for 2009 at ≈ 1200 tonnes. ‘Bottom-up’ estimates from the Emission Database for Global Atmospheric Research (EDGAR) v.4.0 only include emissions from Austria and France in 2005, which total 206 tonnes. For comparison, the global emissions in 2005 from our model equate to ≈ 800 tonnes. Further measurement and modeling efforts are warranted together with projections of future consumption. References: Miller, B. R., R. F. Weiss, P. K

  4. A sparse reconstruction method for the estimation of multi-resolution emission fields via atmospheric inversion

    DOE PAGES

    Ray, J.; Lee, J.; Yadav, V.; ...

    2015-04-29

    Atmospheric inversions are frequently used to estimate fluxes of atmospheric greenhouse gases (e.g., biospheric CO2 flux fields) at Earth's surface. These inversions typically assume that flux departures from a prior model are spatially smoothly varying, which are then modeled using a multi-variate Gaussian. When the field being estimated is spatially rough, multi-variate Gaussian models are difficult to construct and a wavelet-based field model may be more suitable. Unfortunately, such models are very high dimensional and are most conveniently used when the estimation method can simultaneously perform data-driven model simplification (removal of model parameters that cannot be reliably estimated) and fitting.more » Such sparse reconstruction methods are typically not used in atmospheric inversions. In this work, we devise a sparse reconstruction method, and illustrate it in an idealized atmospheric inversion problem for the estimation of fossil fuel CO2 (ffCO2) emissions in the lower 48 states of the USA. Our new method is based on stagewise orthogonal matching pursuit (StOMP), a method used to reconstruct compressively sensed images. Our adaptations bestow three properties to the sparse reconstruction procedure which are useful in atmospheric inversions. We have modified StOMP to incorporate prior information on the emission field being estimated and to enforce non-negativity on the estimated field. Finally, though based on wavelets, our method allows for the estimation of fields in non-rectangular geometries, e.g., emission fields inside geographical and political boundaries. Our idealized inversions use a recently developed multi-resolution (i.e., wavelet-based) random field model developed for ffCO2 emissions and synthetic observations of ffCO2 concentrations from a limited set of measurement sites. We find that our method for limiting the estimated field within an irregularly shaped region is about a factor of 10 faster than conventional approaches. It also

  5. Estimating Bacteria Emissions from Inversion of Atmospheric Transport: Sensitivity to Modelled Particle Characteristics

    SciTech Connect

    Burrows, Susannah M.; Rayner, Perter; Butler, T.; Lawrence, M.

    2013-06-04

    Model-simulated transport of atmospheric trace components can be combined with observed concentrations to obtain estimates of ground-based sources using various inversion techniques. These approaches have been applied in the past primarily to obtain source estimates for long-lived trace gases such as CO2. We consider the application of similar techniques to source estimation for atmospheric aerosols, by using as a case study the estimation of bacteria emissions from different ecosystem regions in the global atmospheric chemistry and climate model ECHAM5/MESSy-Atmospheric Chemistry (EMAC). Simulated particle concentrations in the tropopause region and at high latitudes, as well as transport of particles to tundra and land ice regions are shown to be highly sensitive to scavenging in mixed-phase clouds, which is poorly characterized in most global climate models. This may be a critical uncertainty in correctly simulating the transport of aerosol particles to the Arctic. Source estimation via Monte Carlo Markov Chain is applied to a suite of sensitivity simulations and the global mean emissions are estimated. We present an analysis of the partitioning of uncertainties in the global mean emissions that are attributable to particle size, CCN activity, the ice nucleation scavenging ratios for mixed-phase and cold clouds, and measurement error. Uncertainty due to CCN activity or to a 1 um error in particle size is typically between 10% and 40% of the uncertainty due to data uncertainty, as measured by the 5%-ile to 95%-ile range of the Monte Carlo ensemble. Uncertainty attributable to the ice nucleation scavenging ratio in mized-phase clouds is as high as 10% to 20% of the data uncertainty. Taken together, the four model 20 parameters examined contribute about half as much to the uncertainty in the estimated emissions as do the measurements. This was a surprisingly large contribution from model uncertainty in light of the substantial data uncertainty, which ranges from 81

  6. Emission factors for open and domestic biomass burning for use in atmospheric models

    NASA Astrophysics Data System (ADS)

    Akagi, S. K.; Yokelson, R. J.; Wiedinmyer, C.; Alvarado, M. J.; Reid, J. S.; Karl, T.; Crounse, J. D.; Wennberg, P. O.

    2010-11-01

    Biomass burning (BB) is the second largest source of trace gases and the largest source of primary fine carbonaceous particles in the global troposphere. Many recent BB studies have provided new emission factor (EF) measurements. This is especially true for non methane organic compounds (NMOC), which influence secondary organic aerosol (SOA) and ozone formation. New EF should improve regional to global BB emissions estimates and therefore, the input for atmospheric models. In this work we present an up-to-date, comprehensive tabulation of EF for known pyrogenic species based on measurements made in smoke that has cooled to ambient temperature, but not yet undergone significant photochemical processing. All the emission factors are converted to one standard form (g compound emitted per kg dry biomass burned) using the carbon mass balance method and they are categorized into 14 fuel or vegetation types. We compile a large number of measurements of biomass consumption per unit area for important fire types and summarize several recent estimates of global biomass consumption by the major types of biomass burning. Biomass burning terminology is defined to promote consistency. Post emission processes are discussed to provide a context for the emission factor concept within overall atmospheric chemistry and also highlight the potential for rapid changes relative to the scale of some models or remote sensing products. Recent work shows that individual biomass fires emit significantly more gas-phase NMOC than previously thought and that including additional NMOC can improve photochemical model performance. A detailed global estimate suggests that BB emits at least 400 Tg yr-1 of gas-phase NMOC, which is about 4 times larger than most previous estimates. Selected recent results (e.g. measurements of HONO and the BB tracers HCN and CH3CN) are highlighted and key areas requiring future research are briefly discussed.

  7. Volcanoes as emission sources of atmospheric mercury in the Mediterranean basin

    PubMed

    Ferrara; Mazzolai; Lanzillotta; Nucaro; Pirrone

    2000-10-02

    Emissions from volcanoes, fumaroles and solfataras as well as contributions from widespread geological anomalies could represent an important source of mercury released to the atmosphere in the Mediterranean basin. Volcanoes located in this area (Etna, Stromboli and Vulcano) are the most active in Europe; therefore, it is extremely important to know their mercury contributions to the regional atmospheric budget. Two main methods are used for the evaluation of volcanic mercury flux: a direct determination of the flux (by measuring in the plume) and an indirect one derived from the determination of the Hg/SO2 (or Hg/S) ratio value, as SO2 emissions are constantly monitored by volcanologists. An attempt to estimate mercury flux from the Vulcano volcano and to establish the Hg/S ratio value has been made along three field campaigns carried out in October 1998, in February and May 1999 sampling several fumaroles. Traditional sampling methods were used to collect both total Hg and S. The average Hg/S ratio value resulted to be 1.2 x 10(-7). From the Hg/S value we derived the Hg/SO2 value, and by assuming that all the volcanoes located in this area have the same Hg/SO2 ratio, mercury emissions from Vulcano and Stromboli were estimated to be in the range 1.3-5.5 kg/year and 7.3-76.6 kg/year respectively, while for Etna mercury flux ranged from 61.8 to 536.5 kg/year. Data reported in literature appear to be overestimated (Fitzgerald WF. Mercury emission from volcanos. In: 4th International conference on mercury as a global pollutant, August 4-8 1996, Hamburg, Germany), volcanic mercury emission does not constitute the main natural source of the metal.

  8. Nonlinear Source -" Receptor Relationship due to Interactions between Atmospheric Constituents, Water Cycle and Biogenic Emissions

    NASA Astrophysics Data System (ADS)

    Kinne, S.; Feichter, J.; Rast, S.; Bey, I.; Folberth, G.; Pozzoli, L.; Kloster, S.; Stier, P.

    2007-05-01

    Specific economic sectors or source regions emit a wide variety of air pollutants which influence climate and air quality. This includes emissions of greenhouse gases, chemical species which affect the oxidation capacity of the atmosphere and the concentrations of ozone and methane, and aerosol particles or aerosol precursors. Regional climate respectively weather controls transport and removal of pollutants, chemical transformation pathways, particle formation rate and sink processes as well as emissions from natural sources. Interactions between aerosols and trace gases modify their global and regional distributions. Thus, climatic and environmental impacts are not only controlled by amount and chemical composition of pollutant emissions but in addition also by their interactions and the local meteorological conditions in the source region. For the development of mitigation strategies to minimize adverse conditions attributed to climate change and air pollution we need a better understanding of the role of source location, impact of interactions and feedbacks and of the influence of climate change on the chemical composition of the atmosphere. To demonstrate interactions and feedbacks between the cycles of gaseous and particulate atmospheric constituents, the water cycle, the biosphere and the changing climate we will present results of a series of numerical model simulations. Investigations include interactions between greenhouse gas warming, water cycle and aerosol cycle (Feichter et al., 2004), between aerosol cycles (Stier et al., 2006), between marine biogeochemistry and aerosol cycles (Kloster et al., 2006), and between gas-phase air chemistry and aerosol constituents (Pozzoli et al., 2007). The presentation discusses possible interactions and feedbacks and emphasizes the need for a better integration of the different Earth system components in climate and air quality models. Finally, the question whether anthropogenic emissions from different regions

  9. Experimental and theoretical studies of laser-induced breakdown spectroscopy emission from iron oxide: Studies of atmospheric effects

    NASA Astrophysics Data System (ADS)

    Colgan, J.; Barefield, J. E.; Judge, E. J.; Campbell, K.; Johns, H. M.; Kilcrease, D. P.; McInroy, R.; Clegg, S. M.

    2016-08-01

    We report on a comprehensive study of the emission spectra from laser-induced breakdown spectroscopy (LIBS) measurements on iron oxide. Measurements have been made of the emission from Fe2O3 under atmospheres of air, He, and Ar, and at different atmospheric pressures. The effect of varying the time delay of the measurement is also explored. Theoretical calculations were performed to analyze the plasma conditions and find that a reasonably consistent picture of the change in plasma temperature and density for different atmospheric conditions can be reached. We also investigate the sensitivity of the OI 777 nm emission lines to the plasma conditions, something that has not been explored in detail in the previous work. Finally, we also show that LIBS can be used to differentiate between FeO and Fe2O3 by examining the ratio of the intensities of selected Fe emission to O emission lines.

  10. Potential use of milk urea nitrogen to abate atmospheric nitrogen emissions from wisconsin dairy farms.

    PubMed

    Powell, J M; Rotz, C A; Wattiaux, M A

    2014-07-01

    Urinary urea N (UUN) is the principal nitrogen (N) source controlling emissions of ammonia (NH) and nitrous oxide (NO) from dairy manure. The objectives of this study were (i) to study the integrative nature of dietary crude protein (CP) management, secretion of milk urea N (MUN), excretion of UUN, and N emissions from dairy production systems; (ii) to evaluate how associative changes in dietary CP, MUN, and UUN affect atmospheric N emissions from dairy farms; and (iii) to discuss some of the challenges and opportunities to an expanded use of MUN to enhance dietary CP use and decrease UUN excretion and N emissions from dairy farms. Milk urea N records of 37,889 cows in 197 herds in Wisconsin revealed that approximately one half of tested cows were likely consuming dietary CP in excess of requirement. Farm simulations were used to quantify the effect of dietary CP on whole-farm N emissions. At a statewide average MUN of 12.5 mg dL, 48 to 87% of UUN was emitted as NH, with the lowest loss from pasture-based farms and the greatest loss from tie-stall farms. Each 1 mg dL decrease of MUN (range, 16-10 mg dL) provided an associated daily decrease in UUN of 16.6 g per cow, which decreased NH and NO emissions from manure by 7 to 12%. Although more site-specific information is required on herd MUN-UUN relationships and more a reliable interpretation of MUN assay results is needed, monitoring of MUN may be used to enhance dietary CP use and to reduce UUN excretion and N emissions from Wisconsin dairy farms.

  11. Nitrous Oxide Emissions from Biofuel Crops and Atmospheric Aerosols: Associations with Air Quality and Regional Climate

    NASA Astrophysics Data System (ADS)

    Pillai, Priya Ramachandran

    Emissions of greenhouse gases (GHG) and primary release and secondary formation of aerosols alter the earth's radiative balance and therefore have important climatic implications. Savings in carbon dioxide (CO2) emissions accomplished by replacing fossil fuels with biofuels may increase the nitrous oxide (N2O) emissions. Among various atmospheric trace gases, N2O, irrespective of its low atmospheric concentration, is the fourth most important gas in causing the global greenhouse effect. Major processes, those affect the concentration of atmospheric N2O, are soil microbial activities leading to nitrification and denitrification. Therefore, anthropogenic activities such as industrial emissions, and agricultural practices including application of nitrogenous fertilizers, land use changes, biomass combustion all contribute to the atmospheric N2O concentration. The emission rates of N2O related to biofuel production depend on the nitrogen (N) fertilizer uptake efficiency of biofuel crops. However, crops with less N demand, such as switchgrass may have more favorable climate impacts when compared to crops with high N demands, such as corn. Despite its wide environmental tolerance, the regional adaptability of the potential biofuel crop switch grass varies considerably. Therefore, it is important to regionally quantify the GHG emissions and crop yield in response to N-fertilization. A major objective of this study is to quantify soil emissions of N2O from switchgrass and corn fields as a function of N-fertilization. The roles of soil moisture and soil temperature on N2O fluxes were analyzed. These N2O observations may be used to parameterize the biogeochemical models to better understand the impact of different N2O emission scenarios. This study allows for improvements in climate models that focus on understanding the environmental impacts of the climate change mitigation strategy of replacing fossil fuels with biofuels. As a second major objective, the top of the

  12. Short-Chain Chlorinated Paraffins in Zurich, Switzerland--Atmospheric Concentrations and Emissions.

    PubMed

    Diefenbacher, Pascal S; Bogdal, Christian; Gerecke, Andreas C; Glüge, Juliane; Schmid, Peter; Scheringer, Martin; Hungerbühler, Konrad

    2015-08-18

    Short-chain chlorinated paraffins (SCCPs) are of concern due to their potential for adverse health effects, bioaccumulation, persistence, and long-range transport. Data on concentrations of SCCPs in urban areas and underlying emissions are still scarce. In this study, we investigated the levels and spatial distribution of SCCPs in air, based on two separate, spatially resolved sampling campaigns in the city of Zurich, Switzerland. SCCP concentrations in air ranged from 1.8 to 17 ng·m(-3) (spring 2011) and 1.1 to 42 ng·m(-3) (spring 2013) with medians of 4.3 and 2.7 ng·m(-3), respectively. Both data sets show that atmospheric SCCP levels in Zurich can vary substantially and may be influenced by a number of localized sources within this urban area. Additionally, continuous measurements of atmospheric concentrations performed at one representative sampling site in the city center from 2011 to 2013 showed strong seasonal variations with high SCCP concentrations in summer and lower levels in winter. A long-term dynamic multimedia environmental fate model was parametrized to simulate the seasonal trends of SCCP concentrations in air and to back-calculate urban emissions. Resulting annual SCCP emissions in the city of Zurich accounted for 218-321 kg, which indicates that large SCCP stocks are present in urban areas of industrialized countries.

  13. Optical emission spectroscopy of nanosecond repetitively pulsed microplasmas generated in air at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Orriere, Thomas; Moreau, Eric; Benard, Nicolas; Pai, David

    2015-09-01

    Nanosecond repetitively pulsed (NRP) microplasmas are generated in room temperature air at atmospheric pressure, in order to investigate the enhanced control of discharge properties via the combined effects of spatial confinement and nanosecond repetitive pulsing. Discharges were generated using high-voltage pulses of 15-ns duration applied to a tungsten pin-to-pin reactor, with inter-electrode gap distances (d) from 2 mm down to 0.2 mm. Optical emission spectroscopy and electrical characterization performed on the discharge indicate that heat transfer and plasma chemistry are influenced by the microplasma geometry. Ultrafast gas heating is observed upon deducing the rotational temperature of N2 from the measured emission spectrum of the N2 (C -->B) (0, 2) and (1, 3) transition bands, but use of the microplasma geometry (d = 0.2 mm) results in lower gas temperatures than in larger discharge gaps (d = 2 mm), including at high pulse repetition frequency (30 kHz) where substantial steady-state gas heating can occur. The measured Stark broadening of the Hα transition is significantly greater than for previously studied NRP discharges in air at atmospheric pressure, indicating that the maximum electron number density may be correspondingly much greater, up to 1018 cm-3. Furthermore, for NRP microplasmas, the intensities of emission from excited atomic ions (O+ and N+) are much higher than those of excited neutral atoms (O and N), in contrast to NRP discharges generated in larger discharge gaps.

  14. Seasonal Variability in Atmospheric Methane Mixing Ratio and Coastal Methane Emission from the Southwest United Kingdom

    NASA Astrophysics Data System (ADS)

    Yang, Mingxi; Bell, Thomas; Hopkins, Frances; Nightingale, Phil

    2017-04-01

    We report 2+ year observations of atmospheric methane (CH4) mixing ratio and water-to-air CH4 fluxes from the Penlee Point Atmospheric Observatory (PPAO) on the southwest coast of the UK. About 6 km southwest of Plymouth, this coastal site is located at the mouth of the Plymouth Sound, 10 m above mean sea level, and 30 m from the water's edge. Air from the southwest encounters little terrestrial influence and appears to be largely representative of the background North Atlantic. The other wind sectors are affected to a varying degree by natural and anthropogenic terrestrial emissions as well as discharge from the nearby Tamar estuary/Plymouth Sound. Compared to the southwest wind sector, CH4 mixing ratios from terrestrially influenced wind sectors are greater in the mean and also show stronger seasonality (higher in winter than in summer). Novel application of the eddy covariance technique enables a direct and continuous quantification of the water-to-air CH4 fluxes. CH4 emissions from this region exceed predicted CH4 fluxes over the open ocean but are less than estimates from polar regions or freshwater systems. Within the water-facing wind sectors, CH4 emissions are a few times higher when winds are over the Plymouth Sound than when winds are from the southwest, suggesting a source from riverine outflow. Long-term measurements of CH4 fluxes allow us to examine the dependence on wind speed, tide, and water temperature.

  15. Temporal characteristics of atmospheric ammonia and nitrogen dioxide over China based on emission data, satellite observations and atmospheric transport modeling since 1980

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Zhang, Xiuying; Xu, Wen; Liu, Xuejun; Li, Yi; Lu, Xuehe; Zhang, Yuehan; Zhang, Wuting

    2017-08-01

    China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen (Nr). Atmospheric ammonia (NH3) and nitrogen dioxide (NO2) are the most important precursors for Nr compounds (including N2O5, HNO3, HONO and particulate NO3- and NH4+) in the atmosphere. Understanding the changes in NH3 and NO2 has important implications for the regulation of anthropogenic Nr emissions and is a requirement for assessing the consequence of environmental impacts. We conducted the temporal trend analysis of atmospheric NH3 and NO2 on a national scale since 1980 based on emission data (during 1980-2010), satellite observation (for NH3 since 2008 and for NO2 since 2005) and atmospheric chemistry transport modeling (during 2008-2015).Based on the emission data, during 1980-2010, significant continuous increasing trends in both NH3 and NOx were observed in REAS (Regional Emission inventory in Asia, for NH3 0.17 and for NOx 0.16 kg N ha-1 yr-2) and EDGAR (Emissions Database for Global Atmospheric Research, for NH3 0.24 and for NOx 0.17 kg N ha-1 yr-2) over China. Based on the satellite data and atmospheric chemistry transport model (CTM) MOZART-4 (Model for Ozone and Related chemical Tracers, version 4), the NO2 columns over China increased significantly from 2005 to 2011 and then decreased significantly from 2011 to 2015; the satellite-retrieved NH3 columns from 2008 to 2014 increased at a rate of 2.37 % yr-1. The decrease in NO2 columns since 2011 may result from more stringent strategies taken to control NOx emissions during the 12th Five Year Plan, while no control policy has focused on NH3 emissions. Our findings provided an overall insight into the temporal trends of both NO2 and NH3 since 1980 based on emission data, satellite observations and atmospheric transport modeling. These findings can provide a scientific background for policy makers that are attempting to control atmospheric pollution in China. Moreover, the multiple datasets

  16. Constraining Swiss Methane Emissions from Atmospheric Observations: Sensitivities and Temporal Development

    NASA Astrophysics Data System (ADS)

    Henne, Stephan; Leuenberger, Markus; Steinbacher, Martin; Eugster, Werner; Meinhardt, Frank; Bergamaschi, Peter; Emmenegger, Lukas; Brunner, Dominik

    2017-04-01

    Similar to other Western European countries, agricultural sources dominate the methane (CH4) emission budget in Switzerland. 'Bottom-up' estimates of these emissions are still connected with relatively large uncertainties due to considerable variability and uncertainties in observed emission factors for the underlying processes (e.g., enteric fermentation, manure management). Here, we present a regional-scale (˜300 x 200 km2) atmospheric inversion study of CH4 emissions in Switzerland making use of the recently established CarboCount-CH network of four stations on the Swiss Plateau as well as the neighbouring mountain-top sites Jungfraujoch and Schauinsland (Germany). Continuous observations from all CarboCount-CH sites are available since 2013. We use a high-resolution (7 x 7 km2) Lagrangian particle dispersion model (FLEXPART-COSMO) in connection with two different inversion systems (Bayesian and extended Kalman filter) to estimate spatially and temporally resolved CH4 emissions for the Swiss domain in the period 2013 to 2016. An extensive set of sensitivity inversions is used to assess the overall uncertainty of our inverse approach. In general we find good agreement of the total Swiss CH4 emissions between our 'top-down' estimate and the national 'bottom-up' reporting. In addition, a robust emission seasonality, with reduced winter time values, can be seen in all years. No significant trend or year-to-year variability was observed for the analysed four-year period, again in agreement with a very small downward trend in the national 'bottom-up' reporting. Special attention is given to the influence of boundary conditions as taken from different global scale model simulations (TM5, FLEXPART) and remote observations. We find that uncertainties in the boundary conditions can induce large offsets in the national total emissions. However, spatial emission patterns are less sensitive to the choice of boundary condition. Furthermore and in order to demonstrate the

  17. A search for X-ray emission from rich clusters, extended halos around clusters, and superclusters

    NASA Technical Reports Server (NTRS)

    Pravdo, S. H.; Boldt, E. A.; Marshall, F. E.; Mckee, J.; Mushotzky, R. F.; Smith, B. W.; Reichert, G.

    1979-01-01

    The all-sky data base acquired with the HEAO A-2 experiment was searched for X-ray emission on a variety of metagalactic size scales which were either predicted or previously detected. Results in the 0.2-60 keV energy range are presented. The optically richest clusters, including those from which a microwave decrement were observed, appear to be relatively underluminous in X-rays. Observations of Abell 576 show its luminosity to be less than earlier estimates, and moreover less than the luminosity predicted from its microwave decrement, unless the intracluster gas is a factor of approximately 10 hotter than in typical clusters. Near SC0627 there are two X-ray sources, and the identification of the dominant source with SCO627 is probably incorrect. New spectral observations of Abell 401 and 2147, possible superclusters, reveal that they have typical cluster spectra with iron line emission.

  18. Diffusive methane emissions to the atmosphere from Lake Kivu (Eastern Africa)

    NASA Astrophysics Data System (ADS)

    Borges, A. V.; Abril, G.; Delille, B.; Descy, J.-P.; Darchambeau, F.

    2011-09-01

    We report a data set of methane (CH4) concentrations in the surface waters of Lake Kivu obtained during four cruises (March 2007, September 2007, June 2008, and April 2009) covering the two main seasons, rainy (October to May) and dry (June to September). Spatial gradients of CH4 concentrations were modest in the surface waters of the main basin. In Kabuno Bay (a small subbasin), CH4 concentrations in surface waters were significantly higher than in the main basin. Seasonal variations of CH4 in the main basin were strongly driven by deepening of the mixolimnion and mixing of surface waters with deeper waters rich in CH4. On an annual basis, both Kabuno Bay and the main basin of Lake Kivu were over-saturated in CH4 with respect to atmospheric equilibrium (7330% and 2510%, respectively), and emitted CH4 to the atmosphere (39 mmol m-2 yr-1 and 13 mmol m-2 yr-1, respectively). The source of CH4 to atmosphere was two orders of magnitude lower than the CH4 upward flux. The source of CH4 to the atmosphere from Lake Kivu corresponded to ˜60% of the terrestrial sink of atmospheric CH4 over the lake's catchment. A global cross-system comparison of CH4 in surface waters of lakes shows that both Kabuno Bay and the main basin are at the lower end of values in lakes globally, despite the huge amounts of CH4 in the deeper layers of the lake. This is related to the strongly meromictic nature of the lake that promotes an intense removal of CH4 by bacterial oxidation.

  19. Atmospheric-like rotating annulus experiment: gravity wave emission from baroclinic jets

    NASA Astrophysics Data System (ADS)

    Rodda, Costanza; Borcia, Ion; Harlander, Uwe

    2017-04-01

    Large-scale balanced flows can spontaneously radiate meso-scale inertia-gravity waves (IGWs) and are thus in fact unbalanced. While flow-dependent parameterizations for the radiation of IGWs from orographic and convective sources do exist, the situation is less developed for spontaneously emitted IGWs. Observations identify increased IGW activity in the vicinity of jet exit regions. A direct interpretation of those based on geostrophic adjustment might be tempting. However, directly applying this concept to the parameterization of spontaneous imbalance is difficult since the dynamics itself is continuously re-establishing an unbalanced flow which then sheds imbalances by GW radiation. Examining spontaneous IGW emission in the atmosphere and validating parameterization schemes confronts the scientist with particular challenges. Due to its extreme complexity, GW emission will always be embedded in the interaction of a multitude of interdependent processes, many of which are hardly detectable from analysis or campaign data. The benefits of repeated and more detailed measurements, while representing the only source of information about the real atmosphere, are limited by the non-repeatability of an atmospheric situation. The same event never occurs twice. This argues for complementary laboratory experiments, which can provide a more focused dialogue between experiment and theory. Indeed, life cycles are also examined in rotating- annulus laboratory experiments. Thus, these experiments might form a useful empirical benchmark for theoretical and modelling work that is also independent of any sort of subgrid model. In addition, the more direct correspondence between experimental and model data and the data reproducibility makes lab experiments a powerful testbed for parameterizations. Joint laboratory experiment and numerical simulation have been conducted. The comparison between the data obtained from the experiment and the numerical simulations shows a very good

  20. Do oceanic emissions account for the missing source of atmospheric carbonyl sulfide?

    NASA Astrophysics Data System (ADS)

    Lennartz, Sinikka; Marandino, Christa A.; von Hobe, Marc; Cortés, Pau; Simó, Rafel; Booge, Dennis; Quack, Birgit; Röttgers, Rüdiger; Ksionzek, Kerstin; Koch, Boris P.; Bracher, Astrid; Krüger, Kirstin

    2016-04-01

    Carbonyl sulfide (OCS) has a large potential to constrain terrestrial gross primary production (GPP), one of the largest carbon fluxes in the carbon cycle, as it is taken up by plants in a similar way as CO2. To estimate GPP in a global approach, the magnitude and seasonality of sources and sinks of atmospheric OCS have to be well understood, to distinguish between seasonal variation caused by vegetation uptake and other sources or sinks. However, the atmospheric budget is currently highly uncertain, and especially the oceanic source strength is debated. Recent studies suggest that a missing source of several hundreds of Gg sulfur per year is located in the tropical ocean by a top-down approach. Here, we present highly-resolved OCS measurements from two cruises to the tropical Pacific and Indian Ocean as a bottom-up approach. The results from these cruises show that opposite to the assumed ocean source, direct emissions of OCS from the tropical ocean are unlikely to account for the missing source. To reduce uncertainty in the global oceanic emission estimate, our understanding of the production and consumption processes of OCS and its precursors, dimethylsulfide (DMS) and carbon disulphide (CS2), needs improvement. Therefore, we investigate the influence of dissolved organic matter (DOM) on the photochemical production of OCS in seawater by considering analysis of the composition of DOM from the two cruises. Additionally, we discuss the potential of oceanic emissions of DMS and CS2 to closing the atmospheric OCS budget. Especially the production and consumption processes of CS2 in the surface ocean are not well known, thus we evaluate possible photochemical or biological sources by analyzing its covariation of biological and photochemical parameters.

  1. The Atmospheric Effects of HSCT Emissions Simulated by a 3-Wave Interactive Model. Appendix N

    NASA Technical Reports Server (NTRS)

    Shia, R.-L.; Ko, M. K. W.; Sze, N. D.

    1999-01-01

    An interactive model which couples a semi-spectral dynamical model, a radiative transfer code and a two-dimensional chemistry transport model (2-D CTM), is used to assess the atmospheric effects of the High-Speed Civil Transport (HSCT) engine emissions. The residual mean meridional circulation, the zonal-mean temperature and the eddy diffusion coefficients are calculated using zonal means and three longest zonal waves of dynamical variables integrated in the semi-spectral dynamical model. They are used in the 2-D CTM to simulate the distribution of trace gases in the atmosphere. The simulated ozone is sent to the radiative transfer code to calculate the heating rates, which drive the dynamics. This radiative coupling connects the dynamical and photochemical processes and creates feedback when the atmosphere is perturbed. It is found that in most areas the ozone depletion caused by HSCT emissions calculated using the 3-wave model has the features similar to, but with significantly larger magnitude than that calculated by the AER 2-D CTM with prescribed transport parameters and temperature. The difference is mostly due to the differences in the circulation in the two models. The radiative feedback effects are investigated by comparing the ozone depletion calculated with the baseline dynamics and with the dynamics perturbed by the HSCT emissions. The feedback through changes in the residual mean meridional circulation and the eddy diffusion coefficients has moderate effects on the simulated ozone depletion. It reduced the ozone depletion by 20-30% in northern mid and high-latitudes. However, the feedback through changes in the zonal- mean temperature is negligible.

  2. The Lightning and Radio Emission Detector (LRD) instrument. [carried by Galileo Probe into Jupiter's atmosphere

    NASA Technical Reports Server (NTRS)

    Lanzerotti, L. J.; Rinnert, K.; Dehmel, G.; Gliem, F. O.; Krider, E. P.; Uman, M. A.; Umlauft, G.; Bach, J.

    1992-01-01

    The Lightning and Radio Emission Detector (LRD) instrument will be carried by the Galileo Probe into Jupiter's atmosphere. The LRD will verify the existence of lightning in the atmosphere and will determine the details of many of its basic characteristics. The instrument, operated in its magnetospheric mode at distances of about 5, 4, 3, and 2 planetary radii from Jupiter's center, will also measure the RF noise spectrum in Jupiter's magnetosphere. The LRD instrument is composed of a ferrite-core radio frequency antenna and two photodiodes mounted behind individual fisheye lenses. The output of the RF antenna is analyzed both separately and in coincidence with the optical signals from the photodiodes. The RF antenna provides data both in the frequency domain (with three narrow-band channels, primarily for deducing the physical properties of distant lightning) and in the time domain with a priority scheme (primarily for determining from individual RF waveforms the physical properties of closeby-lightning).

  3. The Lightning and Radio Emission Detector (LRD) instrument. [carried by Galileo Probe into Jupiter's atmosphere

    NASA Technical Reports Server (NTRS)

    Lanzerotti, L. J.; Rinnert, K.; Dehmel, G.; Gliem, F. O.; Krider, E. P.; Uman, M. A.; Umlauft, G.; Bach, J.

    1992-01-01

    The Lightning and Radio Emission Detector (LRD) instrument will be carried by the Galileo Probe into Jupiter's atmosphere. The LRD will verify the existence of lightning in the atmosphere and will determine the details of many of its basic characteristics. The instrument, operated in its magnetospheric mode at distances of about 5, 4, 3, and 2 planetary radii from Jupiter's center, will also measure the RF noise spectrum in Jupiter's magnetosphere. The LRD instrument is composed of a ferrite-core radio frequency antenna and two photodiodes mounted behind individual fisheye lenses. The output of the RF antenna is analyzed both separately and in coincidence with the optical signals from the photodiodes. The RF antenna provides data both in the frequency domain (with three narrow-band channels, primarily for deducing the physical properties of distant lightning) and in the time domain with a priority scheme (primarily for determining from individual RF waveforms the physical properties of closeby-lightning).

  4. Trace gas emissions to the atmosphere by biomass burning in the west African savannas

    NASA Technical Reports Server (NTRS)

    Frouin, Robert J.; Iacobellis, Samuel F.; Razafimpanilo, Herisoa; Somerville, Richard C. J.

    1994-01-01

    Savanna fires and atmospheric carbon dioxide (CO2) detection and estimating burned area using Advanced Very High Resolution Radiometer_(AVHRR) reflectance data are investigated in this two part research project. The first part involves carbon dioxide flux estimates and a three-dimensional transport model to quantify the effect of north African savanna fires on atmospheric CO2 concentration, including CO2 spatial and temporal variability patterns and their significance to global emissions. The second article describes two methods used to determine burned area from AVHRR data. The article discusses the relationship between the percentage of burned area and AVHRR channel 2 reflectance (the linear method) and Normalized Difference Vegetation Index (NDVI) (the nonlinear method). A comparative performance analysis of each method is described.

  5. Atmospheric polychlorinated biphenyls in Indian cities: levels, emission sources and toxicity equivalents.

    PubMed

    Chakraborty, Paromita; Zhang, Gan; Eckhardt, Sabine; Li, Jun; Breivik, Knut; Lam, Paul K S; Tanabe, Shinsuke; Jones, Kevin C

    2013-11-01

    Atmospheric concentration of Polychlorinated biphenyls (PCBs) were measured on diurnal basis by active air sampling during Dec 2006 to Feb 2007 in seven major cities from the northern (New Delhi and Agra), eastern (Kolkata), western (Mumbai and Goa) and southern (Chennai and Bangalore) parts of India. Average concentration of Σ25PCBs in the Indian atmosphere was 4460 (± 2200) pg/m(-3) with a dominance of congeners with 4-7 chlorine atoms. Model results (HYSPLIT, FLEXPART) indicate that the source areas are likely confined to local or regional proximity. Results from the FLEXPART model show that existing emission inventories cannot explain the high concentrations observed for PCB-28. Electronic waste, ship breaking activities and dumped solid waste are attributed as the possible sources of PCBs in India. Σ25PCB concentrations for each city showed significant linear correlation with Toxicity equivalence (TEQ) and Neurotoxic equivalence (NEQ) values.

  6. Global N/sub 2/O cycles - Terrestrial emissions, atmospheric accumulation and biospheric effects

    SciTech Connect

    Banin, A.; Lawless, J.G.; Whitten, R.C.; Oser, H.; Oro, J.; Macelroy, R.D.; Klein, H.P.; Devincenzi, D.L.; Young, R.S.

    1984-01-01

    Recent findings concerning the budget and cycles of nitrous oxide on earth are summarized, and the sources and sinks for N/sub 2/O on land, in the ocean, and in the atmosphere are examined in view of the N/sub 2/O concentration increase of 0.2-0.4 percent per year, observed over the period of 1975-1982. Possible atmospheric and biospheric consequences of the N/sub 2/O concentration increase are evaluated. N/sub 2/O emission values are given for several major ecosystem types, such as forest, desert, cultivated land; values from different sources are compared and discussed. Analysis shows an excess of documented sources over sinks by 0-51 Tg N/sub 2/O-N/yr. 63 references.

  7. Gamma-ray Emission of the Earth's Upper Atmosphere in Geographical Coordinates with Fermi-LAT

    NASA Astrophysics Data System (ADS)

    Madlee, S.; Mitthumsiri, W.; Digel, S.; Ruffolo, D. J.

    2016-12-01

    The Earth is extremely bright in gamma rays as viewed by the Fermi Large Area Telescope (LAT). This gamma-ray emission of the Earth is produced by the interactions of cosmic rays (CRs), high-energy particles in space, with the Earth's upper atmosphere. Here we analyze the Earth's photons in the geographical coordinate system (latitude and longitude) from 58 months of data, using the latest version of the LAT event selection (Pass 8). Preliminary results of our analysis, which are the gamma-ray intensity maps of the Earth at energies from 1 to 10 GeV, will be presented. This study provides a better understanding of the geomagnetic field, the Earth's upper atmosphere, and CRs. This project is partially supported by the Thailand Research Fund (Grant TRG5880173 and RTA5980003).

  8. Monitoring of atmospheric aerosol emissions using a remotely piloted air vehicle (RPV)-Borne Sensor Suite

    SciTech Connect

    1996-05-01

    We have developed a small sensor system, the micro-atmospheric measurement system ({mu}-AMS), to monitor and track aerosol emissions. The system was developed to fly aboard a remotely piloted air vehicle, or other mobile platform, to provide real-time particle measurements in effluent plumes and to collect particles for chemical analysis. The {mu}-AMS instrument measures atmospheric parameters including particle mass concentration and size distribution, temperature, humidity, and airspeed, altitude and position (by GPS receiver) each second. The sensor data are stored onboard and are also down linked to a ground station in real time. The {mu}-AMS is battery powered, small (8 in. dia x 36 in.), and lightweight (15 pounds). Aerosol concentrations and size distributions from above ground explosive tests, airbone urban pollution, and traffic-produced particulates are presented.

  9. [Research on the atomic emission spectroscopy of atmospheric pressure plasma process].

    PubMed

    Jin, Jiang; Li, Na; Xu, Lu; Wang, Bo; Jin, Hui-Liang

    2013-02-01

    In the reaction of the atmospheric pressure plasma process, the heat stable process of the atmospheric pressure plasma jet has a direct impact on the removal rate, CF4 is the provider of active F* atom, O2 is important auxiliary gas, and they play an important role in the process. In order to research the rule of the concentration of the 3 parameters upon the atmospheric pressure plasma processing, the atmospheric pressure plasma jet was used for processing and the spectrometer was used to monitor the changes in the process. The experiment indicates that: when the heat is stable, the concentration of the active F* atom essentially remains unchanged; with increasing the concentration of gas CF4, the spectrum of the active F* atom has self-absorption phenomena, so using the atomic emission spectroscopy method to monitor the changes in the concentration of active F* atom generated by CF4 is not completely exact; because O2 can easily react with the dissociation product of CF4, which inhibits the compound of the active F* atom, so in a certain range with increasing the concentration of gas O2, the concentration of the active F* atom becomes strong.

  10. Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Kourtchev, Ivan; Giorio, Chiara; Manninen, Antti; Wilson, Eoin; Mahon, Brendan; Aalto, Juho; Kajos, Maija; Venables, Dean; Ruuskanen, Taina; Levula, Janne; Loponen, Matti; Connors, Sarah; Harris, Neil; Zhao, Defeng; Kiendler-Scharr, Astrid; Mentel, Thomas; Rudich, Yinon; Hallquist, Mattias; Doussin, Jean-Francois; Maenhaut, Willy; Bäck, Jaana; Petäjä, Tuukka; Wenger, John; Kulmala, Markku; Kalberer, Markus

    2016-10-01

    Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks.

  11. Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols.

    PubMed

    Kourtchev, Ivan; Giorio, Chiara; Manninen, Antti; Wilson, Eoin; Mahon, Brendan; Aalto, Juho; Kajos, Maija; Venables, Dean; Ruuskanen, Taina; Levula, Janne; Loponen, Matti; Connors, Sarah; Harris, Neil; Zhao, Defeng; Kiendler-Scharr, Astrid; Mentel, Thomas; Rudich, Yinon; Hallquist, Mattias; Doussin, Jean-Francois; Maenhaut, Willy; Bäck, Jaana; Petäjä, Tuukka; Wenger, John; Kulmala, Markku; Kalberer, Markus

    2016-10-13

    Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks.

  12. Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols

    PubMed Central

    Kourtchev, Ivan; Giorio, Chiara; Manninen, Antti; Wilson, Eoin; Mahon, Brendan; Aalto, Juho; Kajos, Maija; Venables, Dean; Ruuskanen, Taina; Levula, Janne; Loponen, Matti; Connors, Sarah; Harris, Neil; Zhao, Defeng; Kiendler-Scharr, Astrid; Mentel, Thomas; Rudich, Yinon; Hallquist, Mattias; Doussin, Jean-Francois; Maenhaut, Willy; Bäck, Jaana; Petäjä, Tuukka; Wenger, John; Kulmala, Markku; Kalberer, Markus

    2016-01-01

    Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks. PMID:27733773

  13. Sensitizing properties of luminescence centers on the emission of Er3+ in Si-rich SiO2 film

    NASA Astrophysics Data System (ADS)

    Fu, Qianyu; Gao, Yuhan; Li, Dongsheng; Yang, Deren

    2016-05-01

    In this paper, we report on the luminescence-center (LC)-mediated excitation of Er3+ as a function of annealing temperature in Er-doped Si-rich SiO2 (SRO) films fabricated by electron beam evaporation. It is found that the annealing temperature has significant effects on the emission of Er3+ and the specific optical-active point-defects called LCs within Er-doped SRO films. Different luminescence centers generated by the evolution of microstructures during annealing process act as efficient sensitizers for Er3+ in the films when the annealing temperature is below 1100 °C. Moreover, the temperature dependence of the energy coupling between LCs and Er3+ demonstrates the effective phonon-mediated energy transfer process. In addition, when the annealing temperature reaches 1100 °C, the decreased density of activable erbium ions induced by the aggregation of Er will bring detrimental effects on the emission of Er3+. It is demonstrated that an appropriate annealing process can be designed to achieve efficiently enhanced