Line parameter validation using ground-based solar occultation measurements: Water vapor-A case study

Water vapor spectroscopy data for the 720 nm absorption band (4ν polyad) are validated in the context of atmospheric radiative transfer calculations. We validate line parameters from the HITRAN-2000 database and from the ULB-UFR-BIRA database which have been used for the 2004 release of HITRAN. For this purpose, ground-based high resolution observations of the direct solar radiation are compared with simulated spectra. Line parameters are selected for validation based on a full error characterization including instrument noise and uncertainties in the atmospheric profile data. For a subset of the line parameters validated in the present study independent high-accuracy data are available. The comparison with these independent reference data confirms the capability of our approach to improve water vapor spectroscopic data.