La Crau: a European test site for remote sensing validation
Well characterized reference sites are of major importance for the calibration of remote sensors and the validation of retrieval algorithms. A 0.4 km square zone of 'La Crau', an arid area in the South of France, is well established for the calibration of SPOT HRV sensors, and has been regularly used for a variety of remote sensing campaigns. This study reports an investigation of the potential use of a more extended area of La Crau as a validation site for lower spatial resolution satellite sensors. Sample Bidirectional Reflectance Distribution Function (BRDF) measurements were acquired over a large part of the area of La Crau during a 3-week period in July 1995. The data were analysed to provide a detailed spectral characterization of the surface of La Crau and its temporal, directional and spatial variability. The results were used to simulate the three optical channels and the 1.6 mu m channel of the ATSR-2 sensor and compared with ATSR-2 image data from the site.