Some Research and Applications in the CSIRO ( Australia ) Earth Observation Centre on Scene Brightness due to BRDF

Scientists at CSIRO (Australia) engage in a coordinated group of related projects involving land surface reflectance anisotropy. One of the underlying themes of the work is to test/establish the existence of a stable underlying “typology” of BRDF directly attributable to land surface spectral and structural parameters that will allow sensible selections of the “shape functions” used in correction and inversion algorithms. This requires the existence and use of well established field sites and a range of measurements other than radiometer data. There exist established sites now and there are serious canopy and land cover missions planned in the future which may provide more of this type of data. BRDF research in CSIRO EOC Research involves Data Normalisation (AVHRR, Scanners, Videos, Air Photos, calibrations Sites, Panels) Atmospheric Correction (AVHRR, Scanners) Determining Landcover Structure (Photography, Scanners) and BRDF characterisation. At many current Calibration and Validation sites modelled so far around the world, semi-empirical functions seem sufficient. However, for more complex land surfaces, atmospheric & BRDF effects will need to be separated and it is not clear whether and how consistent the results obtained will be. In all cases of the application of scene brightness correction from AVHRR NDVI to video data mosaicking, we have a fundamental issue of whether there is a consistent and simple typology of BRDF? Photography and scanner data, as well as video & AVHRR are all being collated and documented at established sites in Australia in mapped ecological regions to help test the feasibility of the proposed Landcover BRDF Typology and to assess the Australian Structural Typology using simple and detailed models.