Abstract. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) was an
infrared limb emission spectrometer on the Envisat platform. From 2002 to 2012, it
performed pole-to-pole measurements during day and night, producing more than
1000 profiles per day. The European Space Agency (ESA) recently released the
new version 7 of Level 1B MIPAS spectra, in which a new set of time-dependent
correction coefficients for the nonlinearity in the detector response
functions was implemented. This change is expected to reduce the long-term
drift of the MIPAS Level 2 data. We evaluate the long-term stability of ozone
Level 2 data retrieved from MIPAS v7 Level 1B spectra with the IMK/IAA
scientific level 2 processor. For this, we compare MIPAS data with ozone
measurements from the Microwave Limb Sounder (MLS) instrument on NASA's Aura
satellite, ozonesondes and ground-based lidar instruments. The ozonesondes
and lidars alone do not allow us to conclude with enough significance that
the new version is more stable than the previous one, but a clear improvement
in long-term stability is observed in the satellite-data-based drift
analysis. The results of ozonesondes, lidars and satellite drift analysis are
consistent: all indicate that the drifts of the new version are less negative/more positive nearly everywhere above 15 km. The 10-year MIPAS ozone
trends calculated from the old and the new data versions are compared. The
new trends are closer to old drift-corrected trends than the old uncorrected
trends were. From this, we conclude that the nonlinearity correction
performed on Level 1B data is an improvement. These results indicate that
MIPAS data are now even more suited for trend studies, alone or as part of a
merged data record.
Optimal Two-way TOA Localization and Synchronization for Moving User Devices with Clock Drift
