Geophysical validation of temperature retrieved by the ESA Level 2 processor from MIPAS/ENVISAT measurements

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is operating on the ESA ENVIronmental SATellite since March 2002. The high resolution (0.025 cm-1) limb-emission measurements acquired by MIPAS in the first two years of operations constitute a self-consistent set of data with very good geographical and time coverage. These measurements have been re-processed by ESA up to Level 2, with the most recent versions of both Level 1b and Level 2 algorithms. The products of the ESA Level 2 algorithm are geolocated profiles of temperature and of volume mixing ratio of six key atmospheric constituents: H2O, O3, HNO3, CH4, N2O and NO2. As for all the measurements made with innovative instruments and techniques, this data set requires a thorough validation. During the last year, a large team of scientists spent great efforts in the validation of this data set. In particular, the authors of this paper have focused their activities on the validation of temperature. The validation was carried-out by comparing MIPAS retrieved temperature with correlative measurements made by radiosondes, lidars, in-situ and remote sensors operated either from stratospheric balloons or satellites. Preliminary results show that MIPAS profiles are affected by a bias generally consistent with their a-priori estimated systematic error component. This bias is usually localized at the edges of the altitude range covered by the MIPAS scan (6 - 68 km).