1Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung, Karlsruhe, Germany
2Danish Meteorological Institute, Middle Atmosphere Research Division, Copenhagen, Denmark
3Forschungszentrum Jülich, Institut für Chemie und Dynamik der Geosphäre, Jülich, Germany
4Institut für Atmosphäre und Klima, ETH-Hönggerberg, Zürich, Switzerland
5Computational Physics, Inc., Springfield, VA, USA
6E. O. Hulburt Center for Space Research, Naval Research Laboratory, Washington, USA
7Consiglio Nazionale delle Ricerche, Istituto di Scienze dell’Atmosfera e del Clima, Rome, Italy
Abstract. Space borne infrared limb emission measurements by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) reveal the formation of a belt of polar stratospheric clouds (PSCs) of nitric acid trihydrate (NAT) particles over Antarctica in mid-June 2003. By mesoscale microphysical simulations we show that this sudden onset of NAT PSCs was caused by heterogeneous nucleation on ice in the cooling phases of large-amplitude stratospheric mountain waves over the Antarctic Peninsula and the Ellsworth Mountains. MIPAS observations of PSCs before this event show no indication for the presence of NAT clouds with volume densities larger than about 0.3 μm3/cm3 and radii smaller than 3 μm, but are consistent with supercooled droplets of ternary H2SO4/HNO3/H2O solution (STS). Simulations indicate that homogeneous surface nucleation rates have to be reduced by three orders of magnitude to comply with the observations.