Infrared measurements of atmospheric ethane (C2H6) from aircraft and ground‐based solar absorption spectra in the 3000 cm−1 region

A number of prominent Q-branches of the ν7 band of C2H6 have been identified near 3000 cm−1 in aircraft and ground-based infrared solar absorption spectra. The aircraft spectra provide the column amount above 12 km at various altitudes. The column amount is strongly correlated with tropopause height and can be described by a constant mixing ratio of 0.46 ppbv in the upper troposphere and a mixing ratio scale height of 3.9 km above the tropopause. The ground-based spectra yield a column of 9.0 × 1015 molecules cm−2 above 2.1 km; combining these results implies a tropospheric mixing ratio of approximately 0.63 ppbv.