Model, software, and database for computation of line-mixing effects in infrared Q branches of atmospheric CO2: II Minor and asymmetric isotopomers

The influence of line-mixing on the shape of infrared Q branches of minor i sotopomers of CO2 is studied for the first time. Laboratory spectra of isot opically enriched CO2-N-2 mixtures have been measured in the 15 mu m region at the temperatures of 200 and 300 K for total pressures between 1 and 10 atm. Comparisons with measurements for the nu(2) and (nu(1)-nu(2))(1) Q bra nches of the six isotopomers O-(16,O-17,O- or 18)-C-12-O-(16,O-17,O- or 18) demonstrate the quality of the theoretical approach presented in the prece ding paper (Part I). The model is used to generate a set of numerical data (available by ftp) for the prediction of absorption by (OCO)-O-16-C-12-O-18 , (OCO)-O-16-C-12-O-17, (OCO)-O-16-C-13-O-18 (OCO)-O-16-C-13-O-17, and (OCO )-O-17-C-12-O-18 infrared Q branches under atmospheric conditions; this dat abase completes that proposed in the preceding paper and now includes 271 b ands considering the eight most abundant CO2 isotopomers. Its quality is te sted by comparisons with atmospheric limb emission measured by a balloon-bo rne high resolution Fourier transform instrument. The nu(2) Q branches of ( OCO)-O-16-C-12-O-16, (OCO)-O-16-C-13-O-16, (OCO)-O-16-C-12-O-17, and (OCO)- O-16-C-12-O-18 recorded above Alaska have been used. This shows that line m ixing has significant effects, even for minor isotopomers, and is correctly accounted for by the model and data proposed, (C) 1999 Elsevier Science Lt d. All rights reserved.