FIG. 19.
The 1.06 μm dimer feature in the direct beam reflected spectra with varying amounts of H2O for an Earth analogue with a 1.0 bar, 2.0×PAL O2 atmosphere. There is an artificial offset for ease of viewing, and the dashed lines are spectra that do not include any O2 dimer absorption. As in transit transmission, the SNR of the dimer feature varies by less than 20% with respect to the 1.0×H2O case. Additionally, the SNRs for higher-pressure cases should be less affected by changes in H2O concentrations because of greater absorption within the dimer band. (Color graphics available online at www.liebertonline.com/ast)