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  • 1
    Keywords: stratosphere ; troposhere ; water vapour
    Description / Table of Contents: This scientific assessment has been carried out by the WCRP project on Stratospheric Processes and their Role in Climate (SPARC). The objective of the report is to critically review measurements of water vapour in the stratosphere and upper troposphere, in order to consolidate our knowledge and understanding of the distribution of water vapour and its variability on time scales ranging from the seasonal to the long-term inter-annual. Considering the fundamental role of water vapour in climate, and the scarcity of information concerning its distribution, variability and long-term evolution, the need for such an assessment was recognised by the SPARC Scientific Steering Group. The lack of knowledge on water vapour also leads to a large uncertainty in the prediction of climate change. One of the objectives of the assessment was therefore to support the Third IPCC Assessment Report on Climate Change due to be published in 2001. Great effort has been made to prepare the best data sets possible, to retrieve historical data sets, and to make them all available to the assessment team. This report contains an extensive description of the measurements and their associated uncertainties, an assessment of data quality based on comparison studies of the various data sets, and a description of the understanding of the distribution and variability of water vapour in the stratosphere and upper troposphere which ensues from the data. Finally, recommendations are made to ensure that the difficulties met during this work are overcome in order that the remaining uncertainties in our knowledge and understanding can be resolved. The preceding summary also appears in SPARC Newsletter number 16 (January 2001). The outline of the assessment was determined during an international workshop held at NCAR, Boulder, Colorado, USA, 26-28 August 1998. The drafts of the chapters were prepared in the following year and a number of new data sets were produced. The first draft report was examined by an international panel of reviewers both by mail peer review and at a meeting in Paris, France in January 2000. During the review meeting the responses to the mail review comments were proposed by the authors and discussed by the participants. This rigorous review greatly improved the report, the contribution of the reviewers being significant. A second draft report was reviewed by mail review in August 2000. The success in producing the Report is the result of the intensive work and enthusiastic cooperation of a large number of scientists world-wide who have worked towards improving the quality of the measurements and our understanding of the observations. The work of the contributors and reviewers was generously supported by many organisations and agencies including WMO, WCRP, SPARC, DG Research of the European Commission, NASA, NOAA, NCAR, CNRS, CNES, Forschungszentrum Jülich, Imperial College and other national research programmes and institutions. We take this opportunity to express our gratitude to all the scientists (authors, contributors and reviewers) who helped in the preparation of this assessment and to the SPARC scientific steering group who have been supportive since its inception. Our special gratitude is due to the lead authors of the chapters. Particular thanks must be given to: Petra Udelhofen at the SPARC Data Center for setting up the data archive, Sam Oltmans who organised the workshop at NCAR, Boulder, Colorado; Computational Physics Inc., for hosting the workshop in Washington D.C.; François Dulac from the CNES for hosting the review meeting in Paris, and Céline Phillips for her co-editorship. We also thank Marie-Christine Gaucher at the SPARC office for her help in the organisation of the review meeting in Paris and in the final editing of the report and Catherine Michaut at the SPARC office for her help in editing the second peerreview draft and the final draft of the report.
    Pages: Online-Ressource (XVIII, 312 Seiten)
    Language: English
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 332 (1988), S. 240-242 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The method used at Montsouris was 'iodine catalysed oxidation of arsenite in neutral aqueous solution', see equation (1). O3 + AsOi" I Az 〉 O2 + AsO^~ (1) Figure 1 shows the experimental set up, consisting of a bubbler, a precisely calibrated gas meter and a water jet pump8. The ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of atmospheric chemistry 2 (1984), S. 203-210 
    ISSN: 1573-0662
    Keywords: Absorption cross-section ; Ly(α) ; H2O ; O2 ; trace gas detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The absorption cross-sections of water vapor and oxygen were measured, using a low-pressure radio frequency discharge through traces of hydrogen in argon as a light source for Ly(α) radiation. The cross-sections are σH2O = 1.59 × 10−17 cm2 and σO2 = 1.13 × 10−20 + 1.72 × 10−23 for water and oxygen, respectively, where P is the oxygen pressure in units of Torr. Ly(α) lamps, such as used for this work, are important light sources for photochemical laboratory work and find applications for trace-gas detection in the atmosphere. For the latter application, accurate cross-sections of water vapor and oxygen are needed.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-0662
    Keywords: Carbon monoxide ; in-situ measurement ; resonance-fluorescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The development of an airborne instrument for the in-situ measurement of carbon monoxide is described. The technique is resonance-fluorescence of the (A 1Π → X 1Σ) transition of CO in the VUV. The instrument achieves a detection limit of 1 ppb for an interaction time of 10 s from ground level up to an altitude of 34 km. Interferences from other stratospheric trace gases are negligible.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-0662
    Keywords: nitrate radical ; solubility ; sticking coefficient ; redox potential ; heterogeneous removal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The exchange of NO3 radicals with the aqueous-phase was investigated at room temperature (293 K) in a series of wetted denuders. From these experiments, the uptake coefficient of NO3 was determined on 0.1 M NaCl solutions and was found to be γ(NO3) ≥ 2 × 10-3 in good agreement with recent studies. The Henry coefficient of NO3 was estimated to be KH(NO3) = 1.8 M · atm-1, with a (2σ) uncertainty of ±3 M · atm-1. From the upper limit for the Henry coefficient (KH = 5 M · atm-1) and available thermodynamic data, the redox potential of dissolved NO3/NO 3 − is estimated to be in the range of 2.3 to 2.5 V. This range is at the lower boundary of earlier estimates. The results are discussed in the light of a recent publication. Based on our data and a model of the transport and chemistry in the liquid film, an upper limit is derived for the product of the Henry coefficient KH and the rate coefficient k 10 of the potential reaction NO3 + H2O → HNO3 + OH. For KH = 0.6 M · atm-1, we find k 10 〈 0.05 s-1 · atm-1, i.e., about 100 times smaller than what was suggested by Rudich and co-workers. Because of its small solubility, heterogeneous removal of NO3 is only important under conditions where the dissolved NO3 is removed quickly from equilibrium, for example by reactions with Cl− or HSO 3 − ions in the liquid-phase. Otherwise, heterogenous removal should mainly proceed via N2O5.
    Type of Medium: Electronic Resource
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  • 6
    Publication Date: 2013-08-31
    Description: The possibility that the current fleet of subsonic aircraft may already have caused detectable changes in both the troposphere and stratosphere has raised concerns about the impact of such operations on stratospheric ozone and climate. Recent interest in the operation of supersonic aircraft in the lower stratosphere has heightened such concerns. Previous assessments of impacts from proposed supersonic aircraft were based mostly on one-dimensional model results although a limited number of multidimensional models were used. In the past 15 years, our understanding of the processes that control the atmospheric concentrations of trace gases has changed dramatically. This better understanding was achieved through accumulation of kinetic data and field observations as well as development of new models. It would be beneficial to start examining the impact of subsonic aircraft to identify opportunities to study and validate the mechanisms that were proposed to explain the ozone responses. The two major concerns are the potential for a decrease in the column abundance of ozone leading to an increase in ultraviolet radiation at the ground, and redistribution of ozone in the lower stratosphere and upper troposphere leading to changes in the Earth's climate. Two-dimensional models were used extensively for ozone assessment studies, with a focus on responses to chlorine perturbations. There are problems specific to the aircraft issues that are not adequately addressed by the current models. This chapter reviews the current status of the research on aircraft impact on ozone with emphasis on immediate model improvements necessary for extending our understanding. The discussion will be limited to current and projected commercial aircraft that are equipped with air-breathing engines using conventional jet fuel. The impacts are discussed in terms of the anticipated fuel use at cruise altitude.
    Keywords: ENVIRONMENT POLLUTION
    Type: NASA, Washington, Scientific Assessment of Ozone Depletion: 1991; 18 p
    Format: application/pdf
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  • 7
    Publication Date: 2011-08-19
    Description: Measurements performed during stratospheric flights of the U-2 aircraft confirm that cross-jet transport is dominated by waves, not by large-scale circulations. Monotonic gradients of trace constituents normal to the jet axis, with upper stratospheric tracers increasing poleward and tropospheric tracers increasing equatorward, are augmented by large-scale confluence as the jet intensifies during cyclogenesis. These gradients are rotated, intensified, and significantly increased in areas as their mixing ratio surfaces are folded by the differential transport of a very low frequency transverse wave. The quasi-horizontal transport produces a laminar structure with stable layers rich in upper stratospheric tracers alternating vertically with less stable layers rich in tropospheric tracers. The transport proceeds toward irreversibility at higher frequency, shear-gravity waves extend the folding to smaller horizontal scales.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 96; 17
    Format: text
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 8 (1974), S. 54-62 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Publication Date: 1988-03-01
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Springer Nature
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  • 10
    Publication Date: 1980-08-01
    Print ISSN: 0032-0633
    Electronic ISSN: 1873-5088
    Topics: Geosciences , Physics
    Published by Elsevier
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