Line parameters of the P-branch of (30012) ← (00001) 12C16O2 band measured by comb-assisted, Pound-Drever-Hall locked cavity ring-down spectrometer

•The P-branch of the (30012) ← (00001) band of 12C16O2 has been studied with a comb-assisted, Pound-Drever-Hall locked cavity ring-down spectrometer.•Line parameters including transition frequency, line intensity, pressure broadening and shifting coefficients are simultaneously retrieved for lines with rotational quantum number extending to -72.•The uncertainties for the measured spectroscopic parameters are lower than those from HITRAN 2016 and CDSD-296 databases.•The measured transition frequencies agree well those from HITRAN 2016 and CDSD-296 for rotational quantum number m from -32 to -2. Comparatively, the measured transition frequencies show a clear tendency of being smaller for m below -32.