Spectroscopic evidence for NAT, STS, and ice in MIPAS infrared limb emission measurements of polar stratospheric clouds ...

• Main Authors: Höpfner, Michael, Luo, Beiping P., Massoli, Paola, Cairo, Francesco, Spang, Reinhold, Snels, Marcel, Di Donfrancesco, Guido, Stiller, Gabriele, Von Clarmann, Thomas, Fischer, Herbert, Biermann, U.
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2006
• Subjects: Antarc*; Antarctic
• Online Access: https://dx.doi.org/10.3929/ethz-b-000037063; http://hdl.handle.net/20.500.11850/37063

We have analyzed mid-infrared limb-emission measurements of polar stratospheric clouds (PSCs) by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) during the Antarctic winter 2003 with respect to PSC composition. Coincident Lidar observations from McMurdo were used for comparison with PSC types 1a, 1b and 2. Application of new refractive index data of β-NAT have allowed to accurately simulate the prominent spectral band at 820 cm-1 observed by MIPAS at the location where the Lidar instrument observed type 1a PSCs. Broadband spectral fits covering the range from 780 to 960 cm-1 and from 1220 to 1490 cm-1 showed best agreement with the MIPAS measurements when spectroscopic data of NAT were used to simulate the MIPAS spectra. MIPAS measurements collocated with Lidar observations of Type 1b and Type 2 PSCs could only be reproduced by assuming a composition of supercooled ternary H2SO4/HNO3/H2O solution (STS) and of ice, respectively. Particle radius and number density profiles derived from ... : Atmospheric Chemistry and Physics, 6 (5) ...