Nitric Acid Trihydrate (NAT) in Polar Stratospheric Clouds

Christiane Voigt (1) , Jochen Schreiner (1) , Andreas Kohlmann (1) , Peter Zink (1) , Konrad Mauersberger (1) , Niels Larsen (2) , Terry Deshler (3) , Chris Kröger (3) , Jim Rosen (3) , Alberto Adriani (4) , Francesco Cairo (4) , Guido Di Donfrancesco (4) , Maurizio Viterbini (4) , Joelle Ovarlez (5) , Henri Ovarlez (5) , Christine David (6) , Andreas Dörnbrack (7)

1 MPIK - Max-Planck-Institut für Kernphysik
2 DMI - Danish Meteorological Institute
3 Department of Atmospheric Science [Laramie]
4 IFA - Istituto di Fisica dell'Atmosfera del CNR
5 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
6 SA - Service d'aéronomie
7 IPA - DLR Institut für Physik der Atmosphäre

A comprehensive investigation of polar stratospheric clouds was performed on 25 January 2000 with instruments onboard a balloon gondola flown from Kiruna, Sweden. Cloud layers were repeatedly encountered at altitudes between 20 and 24 kilometers over a wide range of atmospheric temperatures (185 to 197 kelvin). Particle composition analysis showed that a large fraction of the cloud layers was composed of nitric acid trihydrate (NAT) particles, containing water and nitric acid at a molar ratio of 3:1; this confirmed that these long-sought solid crystals exist well above ice formation temperatures. The presence of NAT particles enhances the potential for chlorine activation with subsequent ozone destruction in polar regions, particularly in early and late winter.

Domains: Atmospheric and Oceanic Physics [physics.ao-ph]; Ocean, Atmosphere

Christiane Voigt, Jochen Schreiner, Andreas Kohlmann, Peter Zink, Konrad Mauersberger, et al.. Nitric Acid Trihydrate (NAT) in Polar Stratospheric Clouds. Science, 2000, 290 (5497), pp.1756-1758. ⟨10.1126/science.290.5497.1756⟩. ⟨insu-03581885⟩