• Geometry: Spherical refractive atmosphere. Nadir, zenith or limb observations. Simple or Combined Upward and Downard trajectories;

• Wide spectral domain : from 100 to 14000 cm-1 ;

• High spectral resolution : the nominal Atlas Processing Interval may be as high as 5.10-4 cm-1;

• Handling of many types of surface : spectral emissivity, albedos, BRDF/BPDF;

• Solar contribution : any available solar spectrum, including the Doppler shift of solar lines;

• Scattering : by molecules, aerosols and clouds through DISORT, LIDORT or V-LIDORT; including corresponding jacobians;

• Polarization: with V-LIDORT.