Stratosphere masses

Viggiano A A 1993 In-situ mass spectrometry and ion chemistry in the stratosphere and troposphere Mass Spectron. Rev. 12 115-37... 

Schlager H and Arnold F 1985 Balloon-borne fragment ion mass spectrometry studies of stratospheric positive ions unambiguous detection of H (CH3CN), (H20)-clusters Pianet. Space Sc/. 33 1363-6... 

Arnold F and Henschen G 1978 First mass analysis of stratospheric negative ions Nature 257 521-2 Eisele F L 1989 Natural and anthropogenic negative ions in the troposphere J. Geophys. Res. 94 2183-96 Oka T 1997 Water on the sun—molecules everywhere Science 277 328-9... 

C05-0071. Freons (CFCs) are compounds that contain carbon, chlorine, and fluorine in various proportions. They are used as foaming agents, propellants, and refrigeration fluids. Freons are controversial because of the damage they do to the ozone layer in the stratosphere. A 2.55-g sample of a particular Freon in a 1.50-L bulb at 25.0 °C has a pressure of 262 torr. What is the molar mass and formula of the compound ... 

Mass Independent Isotope Fractionation in the Laboratory, the Stratosphere, and the Troposphere... 

Thiemens MH, Heidenreich JE (1983) The mass independent fractionation of oxygen a novel isotope effect and its possible cosmochemical implications. Science 219 1073-1075 Thiemens MH, Jackson TL, Brenninkmeijer CAM (1995) Observation of a mass-independent oxygen isotopic composition in terrestrial stratospheric COj, the link to ozone chemisdy, and the possible occurrence in the Martian atmosphere. Geophys Res Lett 22 255-257 Timmes FX, Woosley SE, Weaver TA(1995) Galactic chemical evolution hydrogen through zinc. Astrophys J Suppl 98 617-658... 

One of the first chemical reactions for which SIKIE was identified was the association reaction of Oj and O to produce ozone. The initial key observation was that stratospheric ozone was enriched in 0 at levels up to 40% above natural abundance. Following laboratory experiments, which showed that the enhancement occurred independently of isotopic mass (i.e., " O3 and were equivalently... 

A number of experimental and theoretical studies have focused on the causes of mass-independent fractionation effects, but as summarized by Thiemens (1999), the mechanism for mass-independent fractionations remains uncertain. The best studied reaction is the formation of ozone in the stratosphere. Mauersberger et al. (1999) demonstrated experimentally that it is not the symmetry of a molecule that determines the magnitude of enrichment, but it is the difference in the geometry of the molecule. Gao and Marcus (2001) presented an advanced model, which has led to a better understanding of nonmass-dependent isotope effects. 

Mass-independent isotopic fractionations are widespread in the earth s atmosphere and have been observed in O3, CO2, N2O, and CO, which are all linked to reactions involving stratospheric ozone (Thiemens 1999). For oxygen, this is a characteristic marker in the atmosphere (see Sect. 3.9). These processes probably also play a role in the atmosphere of Mars and in the pre-solar nebula (Thiemens 1999). Oxygen isotope measurements in meteorites demonstrate that the effect is of significant importance in the formation of the solar system (Clayton et al. 1973a) (Sect. 3.1). 

The 8 N- and 8 0-values of atmospheric N2O today, range from 6.4 to 7.0%c and 43 to 45.5%c (Sowers 2001). Terrestrial emissions have generally lower 8-values than marine sources. The 8 N and 8 0-values of stratospheric N2O gradually increase with altitude due to preferential photodissociation of the lighter isotopes (Rahn and Wahlen 1997). Oxygen isotope values of atmospheric nitrous oxide exhibit a mass-independent component (Cliff and Thiemens 1997 Clifif et al. 1999), which increases with altitude and distance from the source. The responsible process has not been discovered so far. First isotope measurements of N2O from the Vostok ice core by Sowers (2001) indicate large and 0 variations with time (8 N from 10 to 25%c and 8 0 from 30 to 50%c), which have been interpreted to result from in situ N2O production via nitrification. 

Ozone has become one of the most important molecules in atmospheric research. In situ mass-spectrometric measurements by Mauersberger (1981, 1987) demonstrated that an equal enrichment in O and 0 of about 40% exists in the stratosphere, with a maximum at about 32 km. The rate of formation of isotopically partially substituted ozone (mass 50) is obviously faster than that of unsubstituted ozone (mass 48). Later measurements by Krankowsky et al. (2000) did not confirm the very large emichments originally reported by Mauersberger, but gave enrichments of 7-11%. Similar mass-independent fractionations have been observed in laboratory experiments by Thiemens and Heidemeich (1983) which are clearly temperature dependent. 

Another oxygen isotope fractionation effect is documented in CO2 samples collected between 26 and 35 km altitude, which show a mass - independent enrichment in both 0 and 0 of up to about 15%c above tropospheric values (Thiemens et al. 1995). The enrichment of stratospheric CO2 relative to tropospheric CO2 should make it possible to study mixing processes across the tropopause. 

Baroni M, Thiemens MH, Delmas RJ, Savarino J (2007) Mass-independent sulfur isotopic composition in stratospheric volcanic eruptions. Science 315 84-87 Barth S (1993) Boron isotope variations in nature a synthesis. Geologische Rundschau 82 640-651... 

Clayton RN, Goldsmith JR, Karel KJ, Mayeda TK, Newton RP (1975) Limits on the effect of pressure in isotopic fractionation. Geochim Cosmochim Acta 39 1197-1201 Clayton RN, Onuma N, Grossman C, Mayeda TK (1977) Distribution of the presolar component in Allende and other carbonaceous chondrites. Earth Planet Sd Lett 34 209-224 Clayton RN, Goldsmith JR, Mayeda TK (1989) Oxygen isotope fractionation in quartz, albite, anorthite and caldte. Geochim Cosmochim Acta 53 725-733 Cliff SS, Thiemens MH (1997) The 0/ 0 and 0/ 0 ratios in atmospheric nitrous oxide a mass independent anomaly. Science 278 1774-1776 Cliff SS, Brenninkmeijer CAM, Thiemens MH (1999) First measurement of the 0/ 0 and ratios in stratospheric nitrous oxide a mass-independent anomaly. J Geophys Res 104 16171-16175... 

Rafter TA (1957) Sulphur isotopic variations in nature, P 1 the preparation of sulphur dioxide for mass spectrometer examination, N Z J Sci Tech B38 849 Rahn T, Wahlen M (1997) Stable isotope enrichment in stratospheric nitrous oxide. Science 278 1776-1778... 

Mass spectrometry has the potential for being a very powerful analytical technique for atmospheric measurements, and indeed, it has been used for a number of decades in upper atmosphere measurements of ions and neutrals. Viggiano (1993) has reviewed ion chemistry and the application of mass spectrometry to tropospheric and stratospheric measurements through 1993. The first mass spectrometric measurements were made in the upper atmosphere from 64 to 112 km in 1963 (Narcisi and Bailey, 1965), followed by stratospheric measurements in 1977 (Arnold et al., 1977) and, finally, tropospheric measurements in 1983 (Eisele, 1983 Heit-mann and Arnold, 1983). They have also been extended... 

Table 11.4 summarizes measurements of various species in the stratosphere and troposphere by mass spectrometry through the early 1990s (Viggiano, 1993, and references therein). The altitude at which they were measured and the concentration ranges are shown, as well as whether they were detected using positive or negative ions (see later discussion). 

FIGURE 11.17 Schematic of mass spectrometer used for stratospheric measurements (IG = ion getter pump, PS = pressure sensor) (adapted from Arnold and Hauck, 1985). 

Arnold, F., D. Krankowsky, and K. H. Marien, First Mass Spec-trometric Measurements of Positive Ions in the Stratosphere, Nature, 267, 30-31 (1977). 

Arnold, F., and G. Hauck, Lower Stratosphere Trace Gas Detection Using Aircraft-Borne Active Chemical Ionization Mass Spectrometry, Nature, 315, 307-309 (1985). 

Water vapor concentrations have also been used to show that stratospheric air in the midlatitudes cannot all have originated via the tropical pump, i.e., path I in Fig. 12.3. For example, Dessler et al. (1995b) have shown that water vapor concentrations in the lowermost stratosphere at 37.4°N, 122.1°W are higher than expected for an air mass that has passed through the cold tropical tropopause. Their data are consistent with path II, although as they point out, these measurements do not exclude path III, which represents convective transport from the troposphere to the stratosphere at mid and high latitudes. Lelieveld et al. (1997) report aircraft measurements of CO, 03, and HNO-, over western Europe that suggest that tropospheric air can be mixed into the lower stratosphere. 

Because Type I PSCs may consist of NAT under some conditions, uptake of HC1 onto crystalline NAT as well as ice surfaces is of interest. As reviewed by DeMore et al. (1997), the mass accommodation coefficient for HC1 on both ice and NAT at stratospheric temperatures is very large, approaching unity. 

FIGURE 12.37 (a) CIO concentrations and (b) HCI deficit at various minimum temperatures experienced by the air masses in the Arctic stratosphere during October 1991-February 1992 (adapted from Toohey et al. (1993) and Webster et al. (1993a)). 

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