The Potential for Ozone Depletion in the Arctic Polar Stratosphere

Abstract

The nature of the Arctic polar stratosphere is observed to be similar in many respects to that of the Antarctic polar stratosphere, where an ozone hole has been identified. Most of the available chlorine (HCl and ClONO(2)) was converted by reactions on polar stratospheric clouds to reactive ClO and Cl(2)O(2) throughout the Arctic polar vortex before midwinter. Reactive nitrogen was converted to HNO(3), and some, with spatial inhomogeneity, fell out of the stratosphere. These chemical changes ensured characteristic ozone losses of 10 to 15% at altitudes inside the polar vortex where polar stratospheric clouds had occurred. These local losses can translate into 5 to 8% losses in the vertical column abundance of ozone. As the amount of stratospheric chlorine inevitably increases by 50% over the next two decades, ozone losses recognizable as an ozone hole may well appear.

Evaluation of stratospheric chlorine chemistry for the Arctic spring 2005 using modelled and measured OClO column densities

“…The recent photo-ionisation mass spectroscopy study by Plenge et al (2005) suggests that the ClOOCl is by a factor of 0.3 less stable than previously assumed. This observation is confirmed at atmospheric temperatures by several studies based on air-borne in-situ measurements (Brune et al, 1991;Pierson et al, 1999;Avallone and Toohey, 2001;Stimpfle et al, 2004;von Hobe et al, 2005) and nighttime Odin satellite/ Osiris measurements (Berthet et al, 2005). By changing the equilibrium constant to the most recent value obtained by Bröske and Zabel (2006), a maximum increase in OClO of 3% at 90 • SZA is achieved.…”

Can ozone depletion and global warming interact to produce rapid climate change?

“…2. Consistent with the colder ambient conditions, indications of an incipient ozone hole have appeared in the NH (45)(46)(47). Some of the ozone decline during the 1980s (48) and 1990s (49) in the NH is a result of reduced ozone transport associated with decreased planetary wave activity.…”

Finite-Temperature Effects on the Stability and Infrared Spectra of HCl(H2O)6 Clusters

“…Chlorine radicals activated at the ice surfaces of polar stratospheric cloud particles are believed to play an important role in atmospheric ozone depletion in polar regions. [1][2][3][4] Laboratory data leading to molecular descriptions of the reactions are sparse due to the difficulty of performing surface experiments on a high vapor pressure material such as ice. 5 As a consequence, the chemical pathway is not understood in detail.…”

“…18 Re et al found that proton transfer in the hydrogen-bonded cluster HCl(H 2 O) n with n ) 1-5 completely occurs only in the case of n ) 5 clusters. 19 Using the B3LYP density functional method and the CCSD(T) ab initio method, Milet et al showed however that HCl starts dissociating already in HCl(H 2 O) 4 . 20 Devlin et al, using ab initio Monte Carlo simulations found that in HCl-(H 2 O) 6 three-coordinated HCl dissociates directly to form a clearly recognizable solvated Cl -and H 3 O + ion pair.…”