Validation of spectroscopic data in the 1.27 µm spectral region by comparisons with ground-based atmospheric measurements

•Various spectroscopic datasets for O2 absorption lines at 1.27 µm are tested using high-resolution atmospheric spectra.•Averaging spectral residuals over numerous recording enables the detection of systematic differences caused by small changes in spectroscopic data.•Spectroscopic parameters in the HITRAN2016 and GEISA2015 databases lead to large residuals.•Data from recent CRDS studies using the speed dependent Nelkin-Ghatak and first-order line-mixing model give the best agreement with measurements.