VALIDATION OF MIPAS ON ENVISAT BY CORRELATIVE MEASUREMENTS OF MIPAS-STR

We report a preliminary validation of profiles from the MIPAS-Envisat on-line processor of ESA with correlative measurements derived from MIPAS-STR onboard the high-altitude aircraft M55-Geophysica. The validation is made for the 22 July 2002 orbit 2051 in the region of the campaign base in Forli, Italy. Profiles of HNO3 and O3 seem to agree well with the correlative measurements but vertical zigzag features, alternating for even and odd scans, are observed in the MIPAS profiles from Envisat. This behaviour, not observed by MIPAS-STR, is mostly pronounced in the CH4 and N2O data from channel B but also present in the temperature profiles derived from channel A. It is probably caused by deficiencies in the radiometric calibration of the atmospheric spectra which is independently performed for forward and backward interferometer sweeps.