Evaluation of near-infrared spectra measured with the ISM/Phobos-2 Spectrometer on Mars

Kurzfassung

From infrared spectroscopy one obtains valuable information about thechemical and mineralogical composition of a planetary surface and thecomponents of its atmosphere. In 1989 the French infrared spectrometer on board of the Soviet Mars Orbiter Phobos-2 measured eleven sessions with up to 120 lines and 25 samples per line of the Martian surface with a spatial resolution of 22*22 km. Each spectrum contains 64 points between 0.775 and 3.1406 muem. The spectral resolutionwas 12 nm between 0.775 and 1.5105 muem and 24 nm between 1.6383 and 3.1406 muem. The measured spectra are a superposition of reflectance spectra from the surface and transmission spectra from the atmosphere. The first step in the evaluation of the spectra is the correction of the atmospheric influence to single out the reflectance spectra. This results are shown by D. Titov et al. at the EGS Conference in Vienna.Here the results of the evaluation of the reflectance spectra will be shown. One very intersting area is between 800 nm and 1.1 muem, caused by absorption bands of iron oxides. The position of the band minimum depends on the oxidation stage. A correlation with the average albedo of the spectra will be shown.