Operational generation of AVHRR-based level-3 products at the German Remote Sensing Data Centre: status and perspectives

The German Remote Sensing Data Centre (DFD) of the German Aerospace Research Establishment (DLR) has been operating a ground segment for High Resolution Picture Transmission (HRPT) data acquisition, archiving, and distribution since the early 1980s. The station's visibility covers all of Europe. DFD started with the generation of thematic level-3 AVHRR value-added products consisting of Multichannel Sea Surface Temperatures (MCSST) and Normalized Difference Vegetation Indices (NDVI) in March 1993. Additionally, calibrated and registered 5-channel image subsets in two areas have been generated for supporting user-specific applications since 1994. The status of the current level-3 product generation chain as well as corresponding processing algorithms are presented. Perspectives to improve the existing products in terms of channel 1 and 2 radiometric optimization by implementing of a pre-operational atmospheric correction scheme developed by, as well as possibilities to correct the solar channels for anisotropic reflectance with respect to different surfaces are shown. Further, new level-3 products such as geophysical cloud parameters derived using the APOLLO algorithm are presented. Also, first results from various algorithm tests are presented to define an operational land surface temperature (LST) product by estimating surface emissivity based on NDVI time profiles.