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  • 1
    In: Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 9, No. 21 ( 2009-11-02), p. 8189-8197
    Abstract: Abstract. This study reports the first systematic measurements of nitric acid (HNO3) uptake in contrail ice particles at typical aircraft cruise altitudes. During the CIRRUS-III campaign cirrus clouds and almost 40 persistent contrails were probed with in situ instruments over Germany and Northern Europe in November 2006. Besides reactive nitrogen, water vapor, cloud ice water content, ice particle size distributions, and condensation nuclei were measured during 6 flights. Contrails with ages up to 12 h were detected at altitudes 10–11.5 km and temperatures 211–220 K. These contrails had a larger ice phase fraction of total nitric acid (HNO3ice/HNO3tot = 6%) than the ambient cirrus layers (3%). On average, the contrails contained twice as much HNO3ice as the cirrus clouds, 14 pmol/mol and 6 pmol/mol, respectively. Young contrails with ages below 1 h had a mean HNO3ice of 21 pmol/mol. The contrails had higher nitric acid to water molar ratios in ice and slightly higher ice water contents than the cirrus clouds under similar meteorological conditions. The differences in ice phase fractions and molar ratios between developing contrails and cirrus are likely caused by high plume concentrations of HNO3 prior to contrail formation. The location of the measurements in the upper region of frontal cirrus layers might account for slight differences in the ice water content between contrails and adjacent cirrus clouds. The observed dependence of molar ratios as a function of the mean ice particle diameter suggests that ice-bound HNO3 concentrations are controlled by uptake of exhaust HNO3 in the freezing plume aerosols in young contrails and subsequent trapping of ambient HNO3 in growing ice particles in older (age 〉 1 h) contrails.
    Type of Medium: Online Resource
    ISSN: 1680-7324
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2009
    detail.hit.zdb_id: 2092549-9
    detail.hit.zdb_id: 2069847-1
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  • 2
    Online Resource
    Online Resource
    Elsevier BV ; 2000
    In:  Journal of Aerosol Science Vol. 31 ( 2000-9), p. 356-357
    In: Journal of Aerosol Science, Elsevier BV, Vol. 31 ( 2000-9), p. 356-357
    Type of Medium: Online Resource
    ISSN: 0021-8502
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2000
    detail.hit.zdb_id: 242500-2
    detail.hit.zdb_id: 1499134-2
    SSG: 13
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  • 3
    Online Resource
    Online Resource
    American Geophysical Union (AGU) ; 1995
    In:  Geophysical Research Letters Vol. 22, No. 12 ( 1995-06-15), p. 1501-1504
    In: Geophysical Research Letters, American Geophysical Union (AGU), Vol. 22, No. 12 ( 1995-06-15), p. 1501-1504
    Type of Medium: Online Resource
    ISSN: 0094-8276
    Language: English
    Publisher: American Geophysical Union (AGU)
    Publication Date: 1995
    detail.hit.zdb_id: 2021599-X
    detail.hit.zdb_id: 7403-2
    SSG: 16,13
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  • 4
    Online Resource
    Online Resource
    Copernicus GmbH ; 2002
    In:  Atmospheric Chemistry and Physics Vol. 2, No. 4 ( 2002-11-05), p. 307-312
    In: Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 2, No. 4 ( 2002-11-05), p. 307-312
    Abstract: Abstract. We examine the effect of nanometer-sized aircraft-induced aqueous sulfuric acid (H2SO4/H2O) particles on atmospheric ozone as a function of temperature. Our calculations are based on a previously derived parameterization for the regional-scale perturbations of the sulfate surface area density due to air traffic in the North Atlantic Flight Corridor (NAFC) and a chemical box model. We confirm large scale model results that at temperatures T〉210 K additional ozone loss -- mainly caused by hydrolysis of BrONO2 and N2O5 -- scales in proportion with the aviation-produced increase of the background aerosol surface area. However, at lower temperatures (〈 210 K) we isolate two effects which efficiently reduce the aircraft-induced perturbation: (1) background particles growth due to H2O and HNO3 uptake enhance scavenging losses of aviation-produced liquid particles and (2) the Kelvin effect efficiently limits chlorine activation on the small aircraft-induced droplets by reducing the solubility of chemically reacting species. These two effects lead to a substantial reduction of heterogeneous chemistry on aircraft-induced volatile aerosols under cold conditions. In contrast we find contrail ice particles to be potentially important for heterogeneous chlorine activation and reductions in ozone levels. These features have not been taken into consideration in previous global studies of the atmospheric impact of aviation. Therefore, to parameterize them in global chemistry and transport models, we propose the following parameterisation: scale the hydrolysis reactions by the aircraft-induced surface area increase, and neglect heterogeneous chlorine reactions on liquid plume particles but not on ice contrails and aircraft induced ice clouds.
    Type of Medium: Online Resource
    ISSN: 1680-7324
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2002
    detail.hit.zdb_id: 2092549-9
    detail.hit.zdb_id: 2069847-1
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  • 5
    Online Resource
    Online Resource
    American Geophysical Union (AGU) ; 2001
    In:  Geophysical Research Letters Vol. 28, No. 3 ( 2001-02), p. 515-518
    In: Geophysical Research Letters, American Geophysical Union (AGU), Vol. 28, No. 3 ( 2001-02), p. 515-518
    Abstract: We examine the impact of heterogeneous chemistry involving liquid aerosol and ice particles on net ozone (O 3 ) production rates under conditions representative of the midlatitude upper troposphere (UT) and lowermost stratosphere (LS). We demonstrate that heterogeneous effects are controlled by nitrogen oxides (NO x ) and by the location of the air masses relative to the tropopause (TP). The net effect of heterogeneous chemistry is to decrease net O 3 production below the TP (via heterogeneous HO 2 loss) and to cause O 3 destruction above the TP (via heterogeneous chlorine (Cl) activation). In the UT, gas phase chemistry due to non‐methane hydrocarbons (NMHCs) can become as important for O 3 chemistry as heterogeneous reactions, and removal of HO 2 by particles can become more important than changes of hydrogen oxides (HO x ) through heterogeneous bromine (Br) chemistry. In the humid LS, Cl activation can become sufficiently large, so that O 3 depletion occurs at all conceivable values of NO x . Such cold and humid conditions occur frequently enough to reduce the average ozone production rates in the midlatitude LS by more than 10%.
    Type of Medium: Online Resource
    ISSN: 0094-8276 , 1944-8007
    Language: English
    Publisher: American Geophysical Union (AGU)
    Publication Date: 2001
    detail.hit.zdb_id: 2021599-X
    detail.hit.zdb_id: 7403-2
    SSG: 16,13
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  • 6
    Online Resource
    Online Resource
    AIP Publishing ; 1991
    In:  Journal of Applied Physics Vol. 69, No. 7 ( 1991-04-01), p. 3835-3841
    In: Journal of Applied Physics, AIP Publishing, Vol. 69, No. 7 ( 1991-04-01), p. 3835-3841
    Abstract: Analytical and simple numerical calculations of the stopping power of partially ionized high-Z targets are presented. Up to now such calculations are difficult, mainly because of lacking precise average ionization potentials of the target ions. The aim of this paper is both to clarify the importance of a suitable treatment of target ions in different ionization stages and to show by means of general scaling laws and explicit examples, that high-Z plasmas of high density and low ionization degree may have smaller stopping powers than cold matter. The resulting range lengthening of the projectile ions might be of crucial importance for a proper design of pellets in inertial confinement fusion.
    Type of Medium: Online Resource
    ISSN: 0021-8979 , 1089-7550
    Language: English
    Publisher: AIP Publishing
    Publication Date: 1991
    detail.hit.zdb_id: 220641-9
    detail.hit.zdb_id: 3112-4
    detail.hit.zdb_id: 1476463-5
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  • 7
    Online Resource
    Online Resource
    AIP Publishing ; 1991
    In:  Journal of Applied Physics Vol. 69, No. 7 ( 1991-04-01), p. 3842-3848
    In: Journal of Applied Physics, AIP Publishing, Vol. 69, No. 7 ( 1991-04-01), p. 3842-3848
    Abstract: Stopping power calculations of fast ions penetrating a hydrogen plasma target in local thermodynamic equilibrium at arbitrary temperatures are performed. Excited state contributions to the energy loss are included in the framework of the Bethe formalism. Average ionization potentials for the excited ions are given in a quasiclassical approximation. It is shown that the net effect is an enhancement of the stopping power compared to the energy loss when assuming all atoms to be in their ground state.
    Type of Medium: Online Resource
    ISSN: 0021-8979 , 1089-7550
    Language: English
    Publisher: AIP Publishing
    Publication Date: 1991
    detail.hit.zdb_id: 220641-9
    detail.hit.zdb_id: 3112-4
    detail.hit.zdb_id: 1476463-5
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  • 8
    Online Resource
    Online Resource
    Copernicus GmbH ; 2005
    In:  Atmospheric Chemistry and Physics Vol. 5, No. 2 ( 2005-02-21), p. 533-545
    In: Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 5, No. 2 ( 2005-02-21), p. 533-545
    Abstract: Abstract. An aircraft plume model has been developed on the basis of two coupled trajectory box models. Two boxes, one for plume and one for background conditions, are coupled by means of a mixing parameterization based on turbulence theory. The model considers comprehensive gas phase chemistry for the tropopause region including acetone, ethane and their oxidation products. Heterogeneous halogen, N2O5 and HOx chemistry on various types of background and aircraft-induced aerosols (liquid and ice) is considered, using state-of-the-art solubility dependent uptake coefficients for liquid phase reactions. The microphysical scheme allows for coagulation, gas-diffusive particle growth and evaporation, so that the particle development from 1s after emission to several days can be simulated. Model results are shown, studying emissions into the upper troposphere as well as into the lowermost stratosphere for contrail and non-contrail conditions. We show the microphysical and chemical evolution of spreading plumes and use the concept of mean plume encounter time, tl, to define effective emission and perturbation indices (EEIs and EPIs) for the North Atlantic Flight Corridor (NAFC) showing EEI(NOy) and EPI(O3) for various background conditions, such as relative humidity, local time of emission, and seasonal variations. Our results show a high sensitivity of EEI and EPIs on the exact conditions under which emissions take place. The difference of EEIs with and without considering plume processes indicates that these processes cannot be neglected.
    Type of Medium: Online Resource
    ISSN: 1680-7324
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2005
    detail.hit.zdb_id: 2092549-9
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