Institute of Meteorology and Climate Research

Beyond MIPAS/ENVISAT

For decades, the primary task of the SAT group has been the level-2 processing of spectra recorded with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on the Envisat platform. Resulting trace gas distributions have been widely used for scientific studies by the scientific community and the SAT-group themselves. The final data version is just being processed. However, in recent years, overarching projects beyond MIPAS gained more and more importance.

One major work field is the quality control of satellite borne trace gas measurements. While validation of the group's own MIPAS data has always been an important issue, general data characterization and quality control projects spanning multiple satellite missions emerged on the group's agenda. One of these is the IMK-SAT-co-led SPARC Activity ``Water Vapour Assessment - II (WAVAS-II)''. This activity aims at the characterization and validation of water vapour data sets, including space-borne measurements. Results are published in a related special issue. Another SPARC Activity related to data characterization of satellite measurements is ``Towards Unified Error Reporting (TUNER)''. This activity was proposed and is co-led by the SAT group. The goal of this project is to establish conventions how to evaluate and report uncertainties and data characterization of space-borne trace gas measurements in a unified and unambiguous way. Projects within the TUNER framework are the ISSI International Team TUNER and the ESA-funded Project VACUUM-R. Also TUNER results are published in a dedicated special issue.

One of the major fields of MIPAS-based atmospheric research is middle atmospheric circulation. To that end, MIPAS provided the first global data set distributions of the mean age of stratospheric air and trends thereof, inferred from MIPAS SF6 measurements (Stiller et al. 2008; 2012; Haenel et al., 2015; see also: the new ISSI International team 'Stratospheric Age-of-Air: Reconciling Observations and Models'). To overcome the limitations of the age-of-air based analysis of stratospheric circulation, a method was developed that infers global fields of meridional circulation vectors by the direct inversion of the continuity equation, applied to tracer mixing ratio fields obtained with MIPAS (von Clarmann and Grabowski, 2016; von Clarmann et al., 2019, von Clarmann and Grabowski, 2020). This method provides observational knowledge of the stratospheric circulation at an unprecedented detail level.