Abstract
The rotational temperature of the 2v3 methane absorptions in the solar/telluric spectrum and the methane abundance in the earth's atmosphere have been measured and are found to be 243.4 ± 5.3K and 1.137 ± 0.117 cm-atm (STP) in a vertical column, respectively. The data were reduced using the results of laboratory measurements with proper allowance for the fine-structure of the methane absorption manifolds and the effects of vibration-rotation interaction (which causes an enhancement of the R-branch of this band).
