SIMBAD references

Atmospheric water vapor is the principal source of opacity at infrared wavelengths. Spectral observations of a star with a featureless continuum, such as a white dwarf, provide a method of determining atmospheric absorption along the line of sight to the star. Through fitting a site-specific atmospheric transmission model to high-resolution atmospheric absorption measurements, it is possible to determine the water vapor column abundance expressed in millimeters of precipitable water vapor (PWV). While more challenging in interpretation, emission spectra can also be used to derive PWV. This article describes a general algorithm that we have developed for retrieving PWV from both atmospheric transmission and emission spectra. The retrieved PWV values have been validated by intercomparison with contemporaneous measurements provided by radiosonde balloons and emission radiometers.