Global long-term MIPAS data processing

The aim of this project is to perform a level 2 (L2) processing of the version 8 global infrared spectra data set (V8 L1b data) of the Earth’s atmosphere, measured in limb-viewing geometry by the space-borne instrument MIPAS(Michelson Interferometer for Passive Atmospheric Sounding) operated by the European Space Agency (ESA) from 2002–2012. MIPAS was a Fourier transform mid-infrared limb scanning high resolution spectrometer which allowed for simultaneous measurements of more than 30 atmospheric trace species related to atmospheric chemistry and global change. At the Institute for Meteorology and Climate Research (IMK) MIPAS spectra are used for retrieval of vertically resolved profiles of abundances of trace species of the atmosphere. The trace gas distributions are used for the assessment of e.g. stratospheric ozone chemistry, stratospheric cloud physics and heterogeneous chemistry, stratospheric exchange processed with troposphere and mesosphere, intercontinental transport of pollutants in the upper troposphere, effects of solar proton events on stratospheric chemistry, mesospheric dynamics, atmospheric coupling, thermospheric temperature, and validation of climate-chemistry models. In the reporting period 2020/2021 MIPAS data processing was performed on the XC40 (Hazel Hen) and on the HPE Apollo (Hawk) supercomputers. The latter machine was mainly used to perform computationally expensive non-local thermodynamic equilibrium (NLTE) calculations. In the test phase/configuration of the HPE Apollo computer small obstacles had to be overcome, however, our approach which has been proven to successfully and efficiently work on the XC 40, also initially worked for the HPE Apollo and showed good performance. A configuration change with respect to the /tmp-filesystem of the compute nodes, which was heavily used by our processing software for efficiency reasons, unfortunately altered this state. We were forced to use the temporary workspace filesystem instead, which implies a performance degradation. Most of the processing work presented here was done in close collaboration between the Instituto de Astrofísica de Andalucía (IAA) in Granada, Spain, and KIT-IMK. The focus of the current work is the processing of atmospheric trace gases which require computationally expensive NLTE calculations, i.e., H2O, CO, NO, NO2. The progress in the quality of the V8 water vapour data product is demonstrated. First presentations of V8 L2 data of CO, NO, and NO2 are shown. The vertical profiles of version V8 data processed at IMK are available to external data users on http://www.imk-asf.kit.edu/english/308.php .