Results of POLDER in-flight absolute calibration

POLDER is a CNES instrument on-board ADEOS polar orbiting satellite, which was succesfully launched in august 1996. In november 1996, POLDER entered its nominal acquisition phase and functionned perfectly until ADEOS early end of service in june 1997. POLDER is a multispectral imaging radiometer/polarimeter designed to collect global and repetitive observations of the solar radiation reflected by the Earth/Atmosphere System, with a wide field of view (2400 km) and a moderate geometric resolution (6km). The instrument concept is based on telecentric optics, on a rotating wheel carrying 15 spectral filters and polarisers, and on a bidimensionnal CCD detector array. In addition to the classical measurement and mapping characteristics of a narrow-band imaging radiometer, POLDER has a unique ability to measure polarised reflectances using three polarizers (for three of its eight spectral bands, 443 to 910 nm), and to observe target reflectances from 13 different viewing directions during a single satellite pass.