CIRRIS 1A OBSERVATION OF (CO)-C-13-O-16 AND (CO)-C-12-O-18 FUNDAMENTAL-BAND RADIANCE IN THE UPPER-ATMOSPHERE

Fundamental band emission from the nu=1 levels of isotopically substituted (CO)-C-13-O-16 and (CO)-C-12-O-18 has been observed for the first time in the earth's atmosphere. High-resolution earthlimb spectra were obtained in the Cryogenic Infrared Radiance Instrumentation for Shuttle (CIRRIS IA) experiment under both nighttime and daytime conditions. Spectral data between 70 and 150 km tangent height were analyzed in the 4.7 mum wavelength region, providing absolute (CO)-C-12-O-16, (CO)-C-13-O-16, and (CO)-C-12-O-18 column radiances. The minor isotope column radiances are up to 30 times more intense than predicted, based solely on the natural isotopic abundances of C-13 and O-18. The derived line-of-sight radiances were accurately modeled using the Phillips Laboratory Atmospheric Radiance Code, and provide a strong test of radiative transport and excitation algorithms, as well as model climatologies.