FIG. 8.

Reflected spectra for Earth-like atmospheres with 100% PAL O₂ but with different total atmospheric pressures. In the reflected spectrum, there is no fundamental limit to which pressures can be probed in an atmosphere. Assuming a cloud-free case, it is possible to probe the surface layers of the atmosphere. The 1.06 μm dimer feature is fairly weak in the present-day Earth's atmosphere, but it is a very strong feature in atmospheres with greater pressures. The 1.27 μm feature is very strong in most of the spectra.