Measurements of absolute absorption cross sections of ozone in the 185‐to 254‐nm wavelength region and the temperature dependence

Abstract

Laboratory measurements of the relative absorption cross sections of ozone at temperatures 195, 228 and 295 K have been made throughout the 185 to 254 nm wavelength region. The absolute absorption cross sections at the same temperatures have been measured at several discrete wavelengths in the 185 to 250 nm region. The absolute cross sections of ozone have been used to put the relative cross sections on a firm absolute basis throughout the 185 to 255 nm region. These recalibrated cross sections are slightly lower than those of L.T. Molina and M.J. Molina (Journal of Geophysical Research !)1, 1450, 1986), but the differences are within a few percent and would not be significant in atmospheric applications. 1. INTRODUCTION and Daumont et al. give results only at 295 K. The seronomic effects of the recent reductions in In the 185 to 240 nm wavelength region, the the Herzberg continuum absorption cross section of penetration of solar radiation into the Earth's atmo-0 2 resulting from stratospheric [Anderson and Hall, sphere is controlled by 02 and 03, and the transmit-1983, 1986] and laboratory [Cheung et al., 1986; ted radiation is available to dissociate trace species. Jenouvrier et al., 1986; Yoshino et al., 19884] The Herzberg continuum absorption of 02 has its determinations have been studied by Nicolet and photodissociation threshold at 242.2 nm, and its Kennes [1986], who also indicated the significance of maximum cross section of only •7x10 -24 cm 2 occurs uncertainties in the O• cross sections in the 200 to near 202 nm; below 202 nm the absorption cross 240 nm region. They evaluated in detail the section of 02 increases rapidly with the onset of the sensitivity of the stratospheric 02 photodissociation predissociated Schumann-Runge bands. Coinciden-rate to uncertainties in the most recent determinatally, the absorption minimum, •3x10 -•9 cm 2, of O3 tions of solar irradiances, 0 2 cross sections, and Oa occurs also near 202 nm, and the absorption by O3 cross sections. They concluded that uncertainties of increases toward shorter and longer wavelengths. 10% in the O 3 cross section in the 202 to 242 nm The ratio of the cross sections, cr(O•)/cr(O2) , approx-region are magnified into variations of up to 30% in imately doubles for each 5 nm increase in wavelength the 0 2 photolysis rate in the lower stratosphere. between 205 and 240 nm, being about 5x104 at 205 They stressed also that this rate is most sensitive to nm and 8x10 • at 240 nm. In the region 200-240 the absolute O• cross section in precisely the spectral nm, both 0 2 and O• play a joint critical role in interval (200-220 nm)where the differences between atmospheric absorption, whereas O• becomes the the laboratory measurements of the O• cross section principal absorber at 240-350 nm and 0 2 at 100-200 by Inn and Tanaka [1953] and Molina and Molina nm. [1986] are largest. Uncertainties in the Oa cross The recommended cross sections of the World sections are also propagated into uncertainties in the Meteorological Organization (WMO), [1986] were 0 2 c...

Temperature‐dependent absorption cross sections of ozone in the Wulf‐Chappuis band at 759–768 nm

“… No significant differences of ozone concentrations at the inlet and the exit monitor cells was observed showing that loss of ozone is negligible in the gas flow system. In our experimental conditions the temperatures in the exit monitor cell was at above 285 K even when the cavity temperature was at 215 K. The temperature dependence of absorption by O 3 at 253.7 nm is negligible over the temperature range of 295–228 K [ Yoshino et al , 1993]. Hence, the same value of 253.7nm was used all measurements.…”

“…Ozone and oxygen have absorption bands in the visible and near infrared region [ Hill et al , 2003]. A number of laboratory measurements of the O 3 absorption spectrum have been reported [ Yoshino et al , 1988, 1993; Anderson et al , 1991; Anderson and Mauersberger , 1992, 1995; Brion et al , 1993; Burkholder and Talukdar , 1994; Bacis et al , 1998; Johnson et al , 1998; Burrows et al , 1999; Voigt et al , 2001]. However, the reported absolute cross sections at 759–768 nm in the Wulf‐Chappuis band of ozone may be unreliable since any ozone sample necessarily contains O 2 .…”

MAVEN/IUVS Stellar Occultation Measurements of Mars Atmospheric Structure and Composition

“…70390-163.37020 195 Yoshino et al (1996) 163. 37300-192.48810 195 Parkinson et al (2003) 192.48970-199 (2000) 245.00000-320.00000 -set to zero (above the dissociation limit) O 3 99.0000-108.5000 295 Ogawa and Cook (1958) 110.1510-184.6484 295 Mason et al (1996) 184.9223-213.3341 195 Yoshino et al (1993) 213.3400-320.0000 193 Serdyuchenko et al (2014) a Shifted by a factor of 0.45 to adopt for the different temperature. b Used the Rayleigh scattering corrected cross sections and shifted by a factor of 0.45 to adopt for the different temperature.…”

High Resolution Doppler Imager observations of ozone in the mesosphere and lower thermosphere

“…Molecular oxygen absorption cross‐sections are from Gibson et al [1983] (125–176 nm), Koppers and Murtagh [1996] (175–205 nm), and Yoshino et al [1988] (185–242 nm). Ozone absorption cross‐sections are from Ackerman [1971] (λ < 185 nm), Yoshino et al [1993] (185–245 nm), and Molina and Molina [1986] (245–345 nm). The quantum yields for O( 1 D) from ozone photolysis are approximately 90% throughout this spectral region.…”