ESA Version 8 final full mission analysis of MIPAS measurements

Time dependence of the difference between orbit average temperature values, at the four pressure levels indicated in the key, retrieved (with the ORM V8) using L1b products with and without the NL correction implemented. 14 selected couples of L1b products (from October 2002 to October 2011), generated for this purpose, were used (Fig. 23 of Raspollini et al.)

For the final ESA reprocessing of MIPAS data, numerous improvements were implemented in the Level 2 processor Optimised Retrieval Model (ORM) version 8.22 (V8) and its auxiliary data. The processor, auxiliary data, and related topics are presented and discussed by Raspollini et al (2022). The implemented changes involve all aspects of the processing chain, from the modelling of the measurements with the handling of the horizontal inhomogeneities along the line of sight to the use of the optimal estimation technique to retrieve the minor species, from a more sensitive approach to detecting the spectra affected by clouds to a refined method for identifying low quality products. Further improvements in the L2 V8 products derived from the use of the L1b V8 products, which were upgraded to reduce the instrumental temporal drift and to handle the abrupt changes in the calibration gain. The improvements introduced into the ORM V8 L2 processor and its upgraded auxiliary data, together with the use of the L1b V8 products, lead to the generation of the MIPAS L2 V8 products, which are characterised by an increased accuracy, better temporal stability and a greater number of retrieved species.