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 substit uted (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 wer e obtained in the Cryogenic Infrared Radiance Instrumentation for Shut tle (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 col umn radiances are up to 30 times more intense than predicted, based so lely on the natural isotopic abundances of C-13 and O-18. The derived line-of-sight radiances were accurately modeled using the Phillips Lab oratory Atmospheric Radiance Code, and provide a strong test of radiat ive transport and excitation algorithms, as well as model climatologie s.