Tunable laser spectroscopy of CO2 near 2.05 μm: Atmospheric retrieval biases due to neglecting line-mixing

Inclusion of line-mixing into spectroscopic models is required for precise and accurate dry-mole-fraction column CO2 retrievals from a satellite instrument. We measure first-order line-mixing parameters of thirteen 12CO2 20013←0000 CO2 transitions near 2.05 μm using tunable laser spectroscopy. We also report line position measurements of twelve 13CO2 and 18OCO transitions in this spectral region. By incorporating line-mixing into a simple atmospheric model, we show how biases in CO2 retrievals can be generated if line-mixing is ignored.

► Not accounting for line mixing can cause biases in satellite retrieved CO2 greater than 0.5%. ► Tunable laser spectroscopy offers a useful tool for probing absorption lineshapes. ► Line positions are measured for CO2 isotopologues near 2.05 μm.