MIPAS/ENVISAT and GPS-RO/CHAMP measure temperature and water vapour profiles in the troposphere and temperature in the stratosphere. This analysis presents comparisons of the stratospheric temperatures retrieved from MIPAS limb mid-infrared emission measurement using the IMK data processor and from GPS radio occultation observations using GFZ retrieval routines. The data used for comparison are taken from the global observations of 14 days in September/October 2002 and 20 days in October/November 2003. Both individual profiles and zonal means of the temperatures between 8 and 30 km show very good agreement. The global mean differences averaged over the height region of 8 and 30 km are 0.05 and 0.2 K for the periods of 2002 and 2003, respectively. There is a weak tendency for MIPAS temperatures to be slightly lower than GPS-RO/CHAMP in the altitudes below 25 km, but higher above. The hot bias increases with increasing height and reaches a maximum of ~1.5 K at 30 km. Comparisons with corresponding radiosonde data at this altitude show a cold bias of ~1K for CHAMP and a hot bias of ~1K for MIPAS. We investigate the effect of possible bias in the initialization of the GPS occultation data with ECMWF at 43 km to the observed bias at 30 km.

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Wang, D.Y.; Wickert, J. (2004): Cross-Validation of MIPAS/ENVISAT and GPS-RO/CHAMP Temperatures. Joint CHAMP/GRACE Science Meeting (Potsdam 2004).