On the use of O2 spin-rotation lines for elevation angle calibration of atmospheric thermal emission spectra

The magnetic dipole-allowed spin-rotation lines of O₂ potentially can be used for pointing calibration and confirmation of float altitude for far infrared spectra of the stratosphere obtained from balloon platforms. We demonstrate that current deficiencies in the spectroscopic database, particularly the air pressure-broadening coefficients, severely limit the capability of deriving useful pointing calibrations, and that precise pressure-broadening measurements for the transitions actually used in calibration are needed to improve this capability.