February 28, 2007
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Global Climate Change Digest
A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999
FROM VOLUME 5, NUMBER 1, JANUARY 1992
"Deep Optically Thin Cirrus Clouds in the Polar Regions. Part I:
Infrared Extinction Characteristics," C. Prabhakara (Code 613,
NASA-Goddard, Greenbelt MD 20771), J.-M. Yoo et al., J. Appl. Meteor.,
29(12), 1313-1329, Dec. 1990.
Spectral data obtained by the Nimbus satellite in 1970 indicated the
existence of optically thin ice clouds in the upper troposphere that probably
extended into the lower stratosphere in the polar regions during winter and
early spring. Theoretical simulations of infrared spectra in the 8-25 micro m
region indicate they have a vertical stratification in particle size.
"Future Aircraft and Global Ozone," S. Bekki (Dept. Chem., Univ.
Cambridge, Lensfield Rd., Cambridge CB2 1EW, UK), R. Toumi et al., Nature,
354(6350), 193-194, Nov. 21, 1991. From results of a 2-D
radiative-chemical transport model, concluded that in the presence of sulfate
aerosol the impact of high-speed civil transport aircraft on stratospheric ozone
is likely to be much less than previously thought.
"Evidence for Denitrification in the 1990 Antarctic Spring
Stratosphere," Geophys. Res. Lett., 18(11), Nov. 1991.
- "1. Lidar and Temperature Measurements," G.P. Gobbi (Inst. Fis. Atmos., CNR, CP 27, 00044 Frascati, Italy), T. Deshler et al., 1995-1998. The strong and sustained denitrification necessary for Antarctic ozone depletion was examined through balloon soundings. Polar stratospheric clouds (PSCs) appeared only when temperatures were below the condensation point for air with about 1 ppbv nitric acid. Observations show the lower stratosphere was highly denitrified from late winter through early spring of 1990.
- "2. Lidar and Aerosol Measurements," T. Deshler (Dept. Atmos. Sci., Univ. Wyoming, Laramie WY 82071), A. Adriani et al., 1999-2002. Soundings documented the occurrence of PSCs during slow cooling events and a single fast cooling event. In the former a bimodal size distribution was found similar to previous measurements; in the latter the best agreement between measured and calculated scattering ratio implied an amorphous nitric acid/water composition rather than crystalline nitric acid trihydrate.
Two items from J. Atmos. Chem., 13(3), Oct. 1991:
"Application of Physical Adsorption Thermodynamics to Heterogeneous Chemistry on Polar Stratospheric Clouds," S. Elliott (Los Alamos Nat. Lab., Los Alamos NM 87544), R.P. Turco et al., 211-224. Laboratory isotherms for the binding to water ice of several nonheterogeneously active atmospheric gases and of HCl were translated into adsorptive equilibrium constants and surface enthalpies. Extrapolation through the Clausius Clapeyron relation yielded coverage estimates of several percent for HCl, and perhaps HF and HNO3. The adsorbed layer may offer acid or proton sources alternate to the bulk solid for heterogeneous reactions with stratospheric nitrates.
"Temperature-Dependence of Ultraviolet Absorption Cross-Sections of Alternative Chlorofluoroethanes: 2. The 2-chloro-1,1,1,2-tetrafluoroethane--HCFC-124," D. Gillotay (Inst. Aronomie Spatiale de Belgique, Ave. Circulaire 3, B-1180 Bruxelles, Belg.), P.C. Simon, 289-299. Implications of the calculated dependencies for stratospheric chemistry are discussed, and formulae useful in modeling calculations given.
"Chlorine in the Stratosphere," N. Tanaka (Dept. Geol., Yale Univ., Box 6666, New Haven CT 06511), D.M. Rye, Nature, 353(6346), 707, Oct. 24, 1991. Correspondence regarding the measurement of chlorine isotope composition to distinguish anthropogenic from natural chlorine compounds in the stratosphere.
Two items from J. Phys. Chem., 95, 1991.
"Rate Constant and Products of the Reaction between NO3 and ClO over the Temperature Range 353-210 K," P. Biggs et al., R.P. Wayne (Phys. Chem. Lab., S. Parks Rd., Oxford OX1 3QZ, UK), 7746-7751. The rate constant was determined using a newly commissioned discharge-flow apparatus; possible implications of the product OClO in polar stratospheres are discussed.
"Heterogeneous Reactions of Chlorine Nitrate and Hydrogen Chloride on Type I Polar Stratospheric Clouds," M.-T. Leu (Earth Sci. Div., Jet Propulsion Lab., 4800 Oak Grove Dr., Pasadena CA 91109), S.B. Moore, L.F. Keyser, 7763-7771. Experimentally investigated sticking coefficients and reaction probabilities using a fast-flow reactor. Interprets results with a simple model of the influence of substrate composition, and discusses implications for polar ozone chemistry.
Four items from Geophys. Res. Lett., 18(10), Oct. 1991.
"Odd Nitrogen Removal on Background Sulfate Aerosols: Implications for the Ozone Hole," G. Pitari (Dept. Fis., Univ. L'Aquila, 67010 Coppito L'Aquila, Italy), G. Visconti, 1853-1856. Uses a 2-D model with an explicit condensation mechanism to study the dependence of polar ozone loss rate on the sticking coefficient gamma for the reaction converting odd N into nitric acid on sulfate aerosols. A change of gamma from 0.02 to 0.14 has a significant impact in the presence of PSCs, but not with just background aerosol present.
"Homogeneous Freezing Nucleation of Stratospheric Solution Droplets," E.J. Jensen (NASA-Ames, Moffett Field, CA 94035), O.B. Toon, P. Hamill, 1857-1860. Application of classical homogeneous nucleation theory shows that homogeneous freezing of pure water ice in stratospheric solution droplets would occur below about 192 K, but the properties of H2SO4 solution at such temperatures are unknown, and some H2SO4 aerosols may freeze out at 180-195 K.
"HCl Dissolved in Solid Mixtures of Nitric Acid and Ice: Implications for the Polar Stratosphere," J. Marti (School Phys., Univ. Minnesota, Minneapolis MN 55455), K. Mauersberger, D. Hanson, 1861-1864. Reports laboratory studies showing a strong dependence of HCl solubility on the HNO3 content of ice particles, even in trace quantities.
"Relationship of Springtime Ozone Depletion at Arrival Heights, Antarctica, to the 70 HPA Temperatures," S.E. Nichol (New Zealand Meteor. Serv., POB 722, Wellington, N.Z), S. Coulmann, T.S. Clarkson, 1865-1868. Total ozone measurements from Arrival Heights (78øS) show a shift in the ozone-temperature relationship over the last three years, with the same total ozone values associated with progressively higher stratospheric temperatures.
"The Ozone and Aerosol Fine Structure Experiment: Observing the Fine Structure of Ozone and Aerosol Distribution in the Atmosphere from the Salyut 7 Orbiter," J. Geophys. Res., 96(D10), Oct. 20, 1991.
- "1. Introduction and the Occultation Experiment," G.M. Grechko (Inst. Atmos. Phys., Pyzhevsky pereulok 3, 109017 Moscow, Russia), N.F. Elansky et al., 18,647-18,653. The experiments, carried out in September 1985, combined observations of the distribution of species from the attenuation of radiation on tangent routes with photographic observations of the Earth's twilight limb. The method can reconstruct ozone profiles and aerosol extinction profiles in the stratosphere with low errors (5-10%) and high resolution (1 km).
- "2. Formation of the Earth's Twilight Limb Coloration and Radiance: Numerical Calculations," N.F. Elansky (addr. immed. above), M.E. Plotkin et al., 18,655-18,660. Monte Carlo calculations of the Earth's twilight limb spectral radiance and coloration in a model of the spherical atmosphere show that for background aerosol conditions, stratospheric ozone layers 2-3 km thick are manifest in the twilight limb in the form of blue bands with increased color saturation.
- "3. Experimental Results," N.F. Elansky (addr. above), G.M. Grechko et al., 18,661-18,670. Analysis of images reveals typical features of the fine structure of aerosol distribution in the troposphere and stratosphere. The aerosol layered structure was observed in the Northern and Southern Hemispheres at heights of 0-18 km and 0-36 km, respectively.
Comment and reply on "The Space Shuttle's Impact on the Stratosphere," ibid., 96(D9), 17,377-17,378, Sep. 20, 1991.
Two items from Geophys. Res. Lett., 18(9), Sep. 1991:
"A Computational Evaluation of the Gas-Phase ClO Dimerization Thermodynamics," Z. Slanina (Czech. Acad. Sci., Dalejskova 3, CS-18223 Prague 8-Koblyisy, Czech. & Slovak Fed. Rep.), F. Uhl?k, 1703-1706. Evaluation of thermodynamic terms in a wide temperature interval pointed out some features not apparent from experimental observations.
"The Loss of CF2O on Ice, NAT [Nitric Acid Trihydrate] and Sulfuric Acid Solutions," D.R. Hanson (Aeronomy Lab., NOAA, 325 Broadway, Boulder CO 80303), A.R. Ravishankara, 1699-1701. Experimental determination of loss-rate coefficients for CF2O, a degradation product of CFCs, shows that its loss on stratospheric particles is a very slow process compared to annual polar ozone destruction.
"The Reaction Probabilities of ClONO2 and N2O5 on 40 to 75% Sulfuric Acid Solutions," D.R. Hanson (addr. immed. above), A.R. Ravishankara, J. Geophys. Res., 96(D9), 17,307-17,314, Sep. 20, 1991. Experiments showed that the reaction ClONO2 + HCl occurring on sulfuric acid solution of 40-75% by weight will not be a significant source of activated Cl in the stratosphere, although loss of N2O5 and ClONO2 could affect the NOx and ClOx concentrations.
"Altitude Distributions of Stratospheric Constituents from Ground-Based Measurements at Twilight," R.L. McKenzie (Dept. Sci. Res., Lauder, Central Otago 9182, New Zealand), P.V. Johnston et al., ibid., 96(D8), 15,499-15,511, Aug. 20, 1991. A technique for extracting height profiles from ground-based column measurements, applied at Lauder, New Zealand, provides information on the vertical structure of atmospheric absorbers such as ozone, NO2 and pollutants from the surface up to about 50 km.
"Flow Reactor and Triple Quadrupole Mass Spectrometer Investigations of Negative Ion Reactions Involving Nitric Acid: Implications for Atmospheric HNO3 Detection by Chemical Ionization Mass Spectrometry," O. Mhler (M. Planck Inst. Kernphys., POB 103 980, D-6900 Heidelberg, Ger.), F. Arnold, J. Atmos. Chem, 13(1), 33-61, July 1991. Previous stratospheric nitric acid measurements were unimpaired by collisional dissociation processes, while those processes played a major role in previous tropospheric measurements, leading to underestimates.
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