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Journal articles
Wavelength-dependent isotope fractionation in visible light O3 photolysis and atmospheric implications
Abstract : The 17O and 18O isotope fractionation associated with photolysis of O3 in the Chappuis band was determined using a broadband light source with cutoff filters at 455, 550, and 620 nm and narrowband light sources at 530, 617, and 660 nm. The isotope effects follow a mass-dependent fractionation pattern (δ17O/δ18O = 0.53). Contrary to theoretical predictions, fractionations are negative for all wavelength ranges investigated and do not change signs at the absorption cross-section maximum. Our measurements differ from theoretical calculations by as much as 34‰ in inline image = (18J/16J − 1). The wavelength dependence is also weaker than predicted. Photo-induced fractionation is strongest when using a low-wavelength cutoff at 620 nm with inline image = −26.9(±1.4)‰. With decreasing wavelength, fractionation values diminish to inline image = −12.9(±1.3)‰ at 530 nm. Results from an atmospheric model demonstrate that visible light photolysis is the most important tropospheric sink of O3, which thus contributes about one sixth to the ozone enrichment.
https://hal.sorbonne-universite.fr/hal-01358299
Contributor : Christof Janssen Connect in order to contact the contributor
Submitted on : Monday, November 29, 2021 - 4:59:47 PM
Last modification on : Monday, November 29, 2021 - 4:59:49 PM
Contributor : Christof Janssen Connect in order to contact the contributor
Submitted on : Monday, November 29, 2021 - 4:59:47 PM
Last modification on : Monday, November 29, 2021 - 4:59:49 PM
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2015GL066219.pdf
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