The Vis/NIR OMEGA imaging spectrometer on-board Mars Express
Abstract
The Vis/NIR OMEGA imaging spectrometer on-board Mars Express has been operating in Mars orbit since January 2004. The spectral range of OMEGA (352 channels from 0.35 to 5.1 μm) makes it possible to identify H2O and CO2 ices and frosts from their characteristic signatures in the near IR. Constraints on grain size and the volume fraction of dust and ice inclusions can be obtained from the relative depth of the absorption bands (in particular 1.25 μm, 1.5 μm, 2 μm, 3 μm for H2O ice, 1.43 μm, 2 μm, 2.7 μm for CO2 ice). Temperatures > 200 K can be determined from the radiance at 5 μm. The role of ice free aerosols can be assessed from the radiance factor at wavelengths corresponding to saturated ice bands.