Technical Note: Intercomparison of ILAS-II version 2 and 1.4 trace species with MIPAS-B measurements G. Wetzel1, T. Sugita2, H. Nakajima2, T. Tanaka2, T. Yokota2, F. Friedl-Vallon1, A. Kleinert1, G. Maucher1, and H. Oelhaf1 1Institut für Meteorologie und Klimaforschung (IMK), Forschungszentrum Karlsruhe, Karlsruhe, Germany 2National Institute for Environmental Studies, Tsukuba, Japan
Abstract. The Improved Limb Atmospheric Spectrometer (ILAS)-II sensor aboard the
Japanese ADEOS-II satellite was launched into its sun-synchronous orbit on
14 December 2002 and performed solar occultation measurements of trace
species, aerosols, temperature, and pressure in the polar stratosphere until
25 October 2003. Vertical trace gas profiles obtained with the balloon
version of the Michelson Interferometer for Passive Atmospheric Sounding
(MIPAS-B) provide one of the sparse data sets for validating ILAS-II version
2 and 1.4 data. The MIPAS-B limb emission spectra were collected on 20 March
2003 over Kiruna (Sweden, 68° N) at virtually the same location that has
been sounded by ILAS-II about 5.5 h prior to the sampling of MIPAS-B.
The intercomparison of the new ILAS-II version 2 (Northern Hemispheric
sunrise) data to MIPAS-B vertical trace gas profiles shows a good to
excellent agreement within the combined error limits for the species
O3, N2O, CH4, H2O (above 21 km), HNO3, ClONO2,
and CFC-11 (CCl3F) in the compared altitude range between 16 and 31 km
such that these data appear to be very useful for scientific analysis. With
regard to the previous version 1.4 ILAS-II data, significant improvements in
the consistency with MIPAS-B are obvious especially for the species CH4
and H2O, but also for O3, HNO3, ClONO2, NO2, and
N2O5. However, comparing gases like NO2, N2O5, and
CFC-12 (CCl2F2) exhibits only poor agreement with MIPAS-B such
that these species cannot be assumed to be validated at the present time.
Citation: Wetzel, G., Sugita, T., Nakajima, H., Tanaka, T., Yokota, T., Friedl-Vallon, F., Kleinert, A., Maucher, G., and Oelhaf, H.: Technical Note: Intercomparison of ILAS-II version 2 and 1.4 trace species with MIPAS-B measurements, Atmos. Chem. Phys., 8, 1119-1126, doi:10.5194/acp-8-1119-2008, 2008.