Abstract
With the advance of imaging spectroscopy systems, the correction of atmospheric influences has been continuously improved while adapting to the enhanced capabilities of current instruments. High resolutions airborne systems such as APEX, AISA, HYSPEX, and CASI-2/SASI have been developed, and powerful space systems such as ENMAP will soon be available. All these sensors promise high accuracy radiometric measurements and therefore require adequate and efficient pre-processing. This paper focuses on adaptations and improvements of the correction model and the software in order to cope with current and future imaging spectroscopy data. An idealized atmospheric correction scheme is proposed. It uses recent improvements for the automatic atmospheric water vapor retrieval, aerosol optical thickness and model determination, cirrus cloud detection and removal, cloud shadow correction, and adjacency correction as they are implemented in the ATCOR atmospheric correction model. The underlying MODTRAN database of look-up tables of radiative transfer calculations has been recompiled with a higher spectral resolution using the more accurate correlated-k algorithm in atmospheric absorption regions. Another enhancement is the adaptive correction of instrument spectral smile effects in combination with atmospheric correction in order to improve products uniformity. Last but not least, concepts and caveats for the integration of BRDF correction procedures and the integration of the respective spectral reference data are shown. Perspectives are outlined how reliable bi-hemispherical spectral albedo data products will be achieved in future preprocessing systems.
Schläpfer, D