TUNER-compliant error estimation for MIPAS: methodology

Abstract. This paper describes the error estimation for temperature and trace gas mixing ratios retrieved from Michelson Interferometer Passive Atmospheric Sounding (MIPAS) limb emission spectra. The following sources are taken into account: measurement noise, propagated pointing uncertainties in abundances of spectrally interfering species, instrument line shape errors, spectroscopic data terms intensities broadening coefficients. Furthermore, both direct impact volatile persistent gain calibration uncertainties, offset calibration, spectral as well their through calibration-related considered. An source specific to MIPAS upper atmospheric observation mode is propagation smoothing crosstalk combined NO retrieval. Whenever non-local thermodynamic equilibrium modelling used retrieval, related kinetic constants species involved populations excitational states also contribute budget. Both generalized Gaussian perturbation studies estimate components. Error correlations account. Estimated provided a multitude conditions. Some were found random systematic component total estimated error. sequential nature retrievals gives rise entangled errors. These caused by that affect uncertainty final product via multiple pathways, i.e., on one hand, directly, and, other errors preceding retrieval step. tend partly compensate each other. hard-to-quantify effect horizontally non-homogeneous atmosphere unknown considered be major limitations estimation.