Stratospheric ozone isotope enrichments—Revisited

Abstract

Abstract. Ozone isotope data for 4903 and 500 3 are presented, that were obtained from 28 stratospheric samples collected over 10 years onboard balloon payloads. Enrichments for 4903 range from 7 to 9% in the middle stratosphere. This is in very good agreement with laboratoryderived isotope predictions. For 5ø03 most enrichments are between 7 and 11%, a few, however, are too high to be of atmospheric origin. Arguments are presented that stratospheric ozone isotope data are consistent with enrichments determined in laboratory studies when pressure and temperature dependence of the isotope effect is included. Results from recent remote sensing experiments support the values obtained during balloon-borne sample collections. Very high enrichments occasionally measured in the past should be disregarded.

Modelling the budget of middle atmospheric water vapour isotopes

“…et al (1970) fractionation and leads to δ 17 O(O( 3 P))=−27.58‰ and δ 18 O(O( 3 P))=−55.30‰ (Johnston et al, 2000). (iii) O 3 was set to be solely dependent on temperature, because all laboratory data indicate negligible pressure dependence below 100 hPa and because it appears that all reliable atmospheric data agree with the enrichments determined in laboratory studies (Johnson et al, 2000;Mauersberger et al, 2001). The (consistent) laboratory data by Jackson (1988, 1990), Morton et al (1990), and are implemented under the assumption that 80% of the isotope enrichment of O 3 is carried by the asymmetric QOO (Anderson et al, 1989;Janssen et al, 1999;Mauersberger et al, 1999 …”

Absence of isotope exchange in the reaction of N2O + O(1D) and the global Δ17O budget of nitrous oxide

“…Nevertheless, this small source has a significant impact on the triple oxygen isotope signature of atmospheric N 2 O, because O( 1 D) is produced mainly by O 3 photolysis and inherits the large oxygen isotope anomaly of stratospheric and tropospheric O 3 . Mass-spectrometric measurements gave bulk D 17 O values of (26 ± 9)% for tropospheric [Johnston and Thiemens, 1997;Krankowsky et al, 1995] and (34 ± 4)% for stratospheric ozone [Mauersberger et al, 2001] As lower limit we adopt the lower limit of the bulk O 3 observations, i.e., 17% and 31% in the troposphere and stratosphere. This translates into flux-weighted average D 17 O sources of (0.26 ± 0.04)% in the stratosphere and (0.10 ± 0.04)% in the troposphere.…”

Sources of the oxygen isotopic anomaly in atmospheric N2O

“…It is known that atmospheric O 3 is enriched in heavy isotopologues and isotopomers with mass-independent fractionation [Mauersberger, 1987;Krankowsky et al, 2000;Mauersberger et al, 2001;Lämmerzahl et al, 2002;Brenninkmeijer et al, 2003;Thiemens, 2006]. The isotopic composition of atmospheric O 3 [Liang et al, 2006] can be well explained by two processes: formation [Thiemens and Heidenreich, 1983;Mauersberger et al, 1999;Gao and Marcus, 2001] and photolysis [Johnson et al, 2001;Bhattacharya et al, 2002;Blake et al, 2003;Liang et al, 2004;Miller et al, 2005;Prakash et al, 2005] [8] In this paper, we simulate the isotopic fractionation of O 3 and N 2 O in one-dimensional (height) and twodimensional (latitude and height) modes.…”