Wavelength-dependent surface reflectance for modeled planetary environments with stellar irradiation plotted for comparison. The desert surface is primarily kaolinite and was used for the desiccated O₂-dominated climates. The basaltic surface was used for Venus-analog climates. The ocean surface was used for the habitable aqua planet. These data are from the U.S.G.S. spectral library (Clark et al. 2007, see footnote 10), except for the ocean longward of 2 μm, which is from the ASTER spectral library (Baldridge et al. 2009, see footnote 11).