Absorption of solar radiation by O2: Implications for O3 and lifetimes of N2O, CFCl3, and CF2Cl2

Minschwaner, K.; Salawitch, R. J.; Chen, Xinyu

doi:10.1029/93jd00223

Cited by 190 publications

(174 citation statements)

References 96 publications

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“…7 The diurnal average photolysis rate has a maximum in the region of 0-15°latitude and at an altitude of ca. 31 km.…”

Section: Comparison To Experimental Andmentioning

confidence: 99%

“…233 K was chosen because it is characteristic of the temperature of the stratosphere, where maximum photolysis occurs. 6,7 295 K was chosen to represent the temperature of the laboratories in which photolysis experiments were conducted. Figure 4c shows the enrichments predicted by the ZPE model.…”

Section: Enrichment Factorsmentioning

confidence: 99%

“…At 20 km, the "UV window" extends from 197 to 214 nm. 6,7 The UV solar radiation photolyses several gases central to stratospheric chemistry, e.g., CFCs, OCS 8 , and N 2 O:…”

Section: Introductionmentioning

confidence: 99%

“…7 Reaction [2a] is the dominant source of reactive odd nitrogen to the stratosphere. 11 The odd nitrogen reaction cycle is now known to be the most important process removing nonpolar ozone.…”

Section: Introductionmentioning

confidence: 99%

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Photolysis of Nitrous Oxide Isotopomers Studied by Time-Dependent Hermite Propagation

et al. 2001

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Nitrous oxide (N 2 O) plays an important role in greenhouse warming and ozone depletion. Yung and Miller's zero point energy (ZPE) model for the photolysis of N 2 O isotopomers was able to explain atmospheric isotopomer distributions without invoking in situ chemical sources. Subsequent experiments showed enrichment factors twice those predicted by the ZPE model. In this article we calculate the UV spectrum of the key N 2 O isotopomers to quantify the influence of factors not included in the ZPE model, namely, the transition dipole surface, bending vibrational excitation, dynamics on the excited state potential surface, and factors related to isotopic substitution itself. The relative cross-sections are calculated as the Fourier transform of the correlation function of the initial vibrational wave function and the time-propagated wave function, using a Hermite expansion of the time evolution operator. The model uses the electronic structure data recently published by Balint-Kurti and co-workers and makes several predictions. (a) The absolute values of the enrichment factors decrease with increasing temperature. (b) Photolysis of N 2 O will produce "mass-independent" enrichment in the remaining sample. (c) Much of the enrichment is due to decreased heavy isotopomer cross-section over the entire absorption band, in contrast to the wavelength shift predicted by the ZPE model. Consequently, to within the error of the calculation, we predict only minor enrichments at λ < 182 nm. The smaller bending excursion of heavy isotopomers combines with the transition dipole surface to produce a smaller integrated cross-section. This effect is partially countered by the larger fraction of heavy isotopomers in excited bending states; the first three bending states have an integrated intensity ratio of ca. 1:3:6. The model agrees with available experimental enrichment factors and stratospheric balloon infrared remote sensing data to within the estimated error.

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“…7 The diurnal average photolysis rate has a maximum in the region of 0-15°latitude and at an altitude of ca. 31 km.…”

Section: Comparison To Experimental Andmentioning

confidence: 99%

Section: Enrichment Factorsmentioning

confidence: 99%

“…At 20 km, the "UV window" extends from 197 to 214 nm. 6,7 The UV solar radiation photolyses several gases central to stratospheric chemistry, e.g., CFCs, OCS 8 , and N 2 O:…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photolysis of Nitrous Oxide Isotopomers Studied by Time-Dependent Hermite Propagation

et al. 2001

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“…In the new CTM, the SchumannRunge band photolysis rates of 24 species, including N 2 O, were added. The SchumannRunge band radiation flux parameterization developed by Minschwaner et al (1993) was used. Allen and Frederick's parameterization (1982) was used for a NO photolysis-rate calculation.…”

Section: Model Descriptionmentioning

confidence: 99%

Low-N2O Air Masses after the Breakdown of the Arctic Polar Vortex in 1997 Simulated by the CCSR/NIES Nudging CTM.

Akiyoshi

Sugata

Sugita

et al. 2002

Journal of the Meteorological Society of Japan

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Low-concentration N 2 O regions in high latitudes of the lower stratosphere were observed by the Improved Limb Atmospheric Spectrometer (ILAS) for one and half months after the Arctic vortex breakdown in May 1997. A new Chemical Transport Model (CTM), referred to as the CCSR/NIES nudging CTM, has been developed, and used to simulate these low-N 2 O air masses. The simulation shows that one of the air masses had a horizontal scale of 1,000-1,500 km, and remained at high latitudes for 1.5-2.5 months after the polar vortex breakdown. The simulation also shows that the contrast between the N 2 O concentration of the low-N 2 O air mass and that of the ambient air was diminished when the air mass was stretched, which had a considerable influence on the duration of the air mass. From the duration, and the horizontal scale simulated by the CTM, an estimate was made of the horizontal eddy diffusivity after the polar vortex breakdown.

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Stratospheric ozone response to sulfate geoengineering: Results from the Geoengineering Model Intercomparison Project (GeoMIP)

et al. 2014

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Geoengineering with stratospheric sulfate aerosols has been proposed as a means of temporarily cooling the planet, alleviating some of the side effects of anthropogenic CO 2 emissions. However, one of the known side effects of stratospheric injections of sulfate aerosols under present-day conditions is a general decrease in ozone concentrations. Here we present the results from two general circulation models and two coupled chemistry-climate models within the experiments G3 and G4 of the Geoengineering Model Intercomparison Project. On average, the models simulate in G4 an increase in sulfate aerosol surface area density similar to conditions a year after the Mount Pinatubo eruption and a decrease in globally averaged ozone by 1.1À2.1 DU (Dobson unit, 1 DU = 0.001 atm cm) during the central decade of the experiment (2040-2049). Enhanced heterogeneous chemistry on sulfate aerosols leads to an ozone increase in low and middle latitudes, whereas enhanced heterogeneous reactions in polar regions and increased tropical upwelling lead to a reduction of stratospheric ozone. The increase in UV-B radiation at the surface due to ozone depletion is offset by the screening due to the aerosols in the tropics and midlatitudes, while in polar regions the UV-B radiation is increased by 5% on average, with 12% peak increases during springtime. The contribution of ozone changes to the tropopause radiative forcing during 2040-2049 is found to be less than À0.1 W m À2. After 2050, because of decreasing ClO x concentrations, the suppression of the NO x cycle becomes more important than destruction of ozone by ClO x , causing an increase in total stratospheric ozone.

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Absorption of solar radiation by O₂: Implications for O₃ and lifetimes of N₂O, CFCl₃, and CF₂Cl₂

Cited by 190 publications

References 96 publications

Photolysis of Nitrous Oxide Isotopomers Studied by Time-Dependent Hermite Propagation

Photolysis of Nitrous Oxide Isotopomers Studied by Time-Dependent Hermite Propagation

Low-N2O Air Masses after the Breakdown of the Arctic Polar Vortex in 1997 Simulated by the CCSR/NIES Nudging CTM.

Stratospheric ozone response to sulfate geoengineering: Results from the Geoengineering Model Intercomparison Project (GeoMIP)

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