MIPAS Level 2 Processor Prototype from validation to operation
n the research field of atmospheric chemistry a central question for acquired data sets is about validation. Have the data been validated to be useful for science? Has the data set been compared to other data sets? If deviations occur, which cause could be identified? Ultimately, two causes are possible when the same scene is observed: either the acquired raw data set is erroneous (hardware problem) or the data processing infers erroneous information (software problem) In order to make sure that the software works as expected, software validation plays a key role in the overall data set validation campaigns. This paper deals with operational software validation, which is an important component of the entire scientific validation chain. In the framework of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) mission, a sophisticated iterative algorithm scheme has been developed by many contributors, which can be used to infer the concentration of atmospheric trace gases from the measured spectra. Actually, this algorithm has been implemented in three instances for the operational phase of the mission with each fulfilling dedicated tasks: a scientific core implementation for proof of feasibility and scientific validation named Optimized Retrieval Model (ORM) coded according to an Algorithm Theoretical Baseline Document (ATBD) [Carli et al. 2013] an industry standard implementation of the scientific algorithm including the framework around this algorithm for performance reference and operational processor validation alias MIPAS Level 2 Processor Prototype (ML2PP) and a ground segment implementation for operational processing mirroring the ML2PP algorithm referred to as Instrument Processing Facility (IPF) In this paper, Astrium's ML2PP used for processing calibrated MIPAS spectra (included in the level 1B product) into atmospheric profiles (included in the level 2 product) is presented in terms of its General processing scheme, Role during the mission, Software validation concept.