Atmospheric Measurement Techniques Discussions www.atmos-meas-tech-discuss.net 1867-8610 2 2 2009 10.5194/amtd-2-589-2009 http://www.atmos-meas-tech-discuss.net/2/589/2009/ http://www.atmos-meas-tech-discuss.net/2/589/2009/amtd-2-589-2009.html http://www.atmos-meas-tech-discuss.net/2/589/2009/amtd-2-589-2009.pdf 589 620 2009-03-02 The benefit of limb cloud imaging for tropospheric infrared limb sounding S. Adams susanne.adams@uni-trier.de R. Spang P. Preusse G. Heinemann Institute of Chemistry and Dynamics of the Geosphere (ICG) I, Forschungszentrum Jülich, Jülich, Germany Department of Environmental Meteorology, University of Trier, Trier, Germany Advances in detector technology enable a new generation of infrared limb sounders to measure 2-D images of the atmosphere. A proposed limb cloud imager (LCI) mode will measure clouds with very high spatial resolution. For the inference of temperature and trace gas distributions, detector pixels of the LCI have to be combined into super-pixels which provide the required signal-to-noise ratio and information content for the retrievals. This study examines the extent to which tropospheric coverage can be improved in comparison to limb sounding using a fixed field of view with the size of the super-pixels, as in conventional limb sounders. The study is based on cloud topographies derived from (a) IR brightness temperatures (BT) of geostationary weather satellites in conjunction with ECMWF temperature profiles and (b) ice and liquid water content data of the Consortium for Small-scale Modeling-Europe (COSMO-EU) of the German Weather Service. Limb cloud images are simulated by matching the cloud topography with the limb sounding line of sight (LOS). The analysis of the BT data shows that the reduction of the spatial sampling along the track has hardly any effect on the gain in information. 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