Atmospheric radiometry at submillimeter wavelengths

The paper considers the application of broadband emission radiometry in the submillimeter (very far infrared) spectral region for studies of stratospheric water vapor. The detailed spectroscopy of the region is discussed and the effects of spectral contamination due to emission lines of other constituents, notably O(3) and O(2), and to a lesser extent N(2), are determined quantitatively. The O(3) lines arise through electric dipole transitions, the O(2) lines through magnetic dipole transitions, and the N(2) emission results from collision-induced electric dipole effects. Under certain circumstances, emission from these other species can represent a significant fraction of that due to H(2)O itself; it must either be corrected for rather carefully or eliminated in the design of the instrument.