A SIMPLE METHOD OF FULL SPECTRUM RECONSTRUCTION BY A 5-BAND APPROACH FOR OCEAN COLOR APPLICATIONS

Ground truth measurements are necessary for the validation of remotely sensed data. Rapid ship or aircraft spectral measurements of the upwe lling and downwelling (ir)radiance are needed to determine the reflect ance of the water column as well, as to intercalibrate with satellite sensors. Intercalibrations are hindered by the application of differen t instruments with varying spectal bands. It is shown that when an opt ical data bank (ODB) of high resolution spectra (400-720 nm) of a spec ific sea area is available, it is possible to reconstruct new and old reflectance spectra, accurate to within 1 per cent almost over the ful l spectral range, out of the reflectance measured in five bands. The O DB could contain subsurface- or airborne-collected data. It appears to be possible to use simple instruments with five specific bands to com pare with satellite data, even if these differ in central wavelengths. In this way high resolution spectral data could also be stored by mea ns of only five bands. The reconstruction technique used is based upon a multiple regression analysis (MRA) or the OBD. To validate this ful l reflectance spectrum reconstruction method, spectral data collected with different radiometers in different locations were successfully re generated from five key bands (412, 492, 556, 620, and 672 nm). It is proposed that airborne spectral reflectance measurements could remain limited to only five specific spectral bands.