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UP: Fachverband Umweltphysik

UP 8: Poster: Atmosphäre und Aerosole: Datenauswertung und Modellierung

UP 8.4: Poster

Dienstag, 27. März 2007, 14:00–15:00, Poster C

General approach to the quantification of interference errors in infrared remote sounding of the atmosphere — Ralf Sussmann and •Tobias Borsdorff — IMK-IFU, Forschungszentrum Karlsruhe, Garmisch-Partenkirchen, Germany

Error analysis of remote sounding distinguished between "smoothing errors," "forward model errors," "forward model parameter errors," and "retrieval noise errors". We show that for infrared soundings "interference errors" can be significant. They originate from "interfering species" that introduce signatures into the spectral measurement which overlap with the spectral features used for retrieval of the target species. This situation arises in infrared atmospheric spectra where the vibration-rotation bands of different species often overlap. The theoretical formulation requires implementing a generalized state vector including full profile entries for all interfering species in addition to the common practice. This leads to a generalized averaging kernel matrix including here defined "interference kernels". These are used together with climatological covariances for the interfering species to quantify the interference errors. We apply the methods to a real sounding of CO profiles from ground-based solar spectra. We also demonstrate how to minimize overall error, which is a trade-off between minimizing interference errors and the smoothing error. The approach used in this paper can be applied to soundings of all infrared-active atmospheric species and all kind of infrared remote sounding systems.