Above-ground biomass assessment of Mediterranean forests using airborne imaging spectrometry: the DAIS Peyne experiment

In July of 1997, various experimental flights were carried out with the Digital Airborne Imaging Spectrometer (DAIS7915). DAIS7915, or DAIS for short, is a European airborne imaging spectrometer and is maintained and operated by the German Aerospace Centre (DLR) at Oberpfaffenhofen. One of the 1997 experimental sites was the Peyne catchment in southern France. The objectives of the experimental flight were to evaluate the technical performance of DAIS and to assess the feasibility of mapping the above-ground biomass of the Mediterranean mixed oak forest. Field campaigns were organized to collect data for image calibration and for image interpretation and analyses. The technical performance of DAIS in 1997 was reasonable for visible and near-infrared wavelengths. The images in short-wave infrared showed severe striping due to aircraft engine vibrations. Signal-to-noise ratios were modest. Field biomass estimates at 83 locations were used to analyse the image spectra. Various well-known spectral indices and a multiple regression analyses were tested for mapping above-ground biomass. The multiple regression method yielded five spectral bands for biomass prediction. Based on the spatial distribution of the regression residuals, it was possible to indicate the reliability of the biomass prediction as a function of location and as a function of biomass level using geostatistics.