Spectroscopic observations of atmospheric trace gases over Kitt Peak: 1. Carbon dioxide and methane from 1979 to 1985

We have analyzed atmospheric spectra obtained with the Fourier transform spectrometer on Kitt Peak, in Arizona, for absorption by CO 2 and CH 4 . During the period 1979–1985 we find that the CO 2 total column amount was increasing at a rate of 0.4%/yr and that CH 4 was increasing at a rate of 1.1%/yr. This is in substantial agreement with air sampling measurements from other sites. In addition, a weak seasonal variation of ∼2% is detected in CO 2 , but none is seen in CH 4 .