Temperature-dependent air broadening of water in the 1250a1750 cma1 range

A Bruker IFS 120 HR Fourier-transform spectrometer has been used to investigate air broadening of water vapor at a spectral resolution of 3A10a3 cma1 in the wavenumber range 1250a1750 cma1. A new method for generating water vapor/air mixtures employing a 800 l stainless steel mixing vessel and a steady flow through the absorption cell has been developed. A total of 46 measurements have been recorded, 33 (26 water+air, 7 pure water) of which have been used in the final analysis. The measurements covered the temperature range 205a315 K, total air pressure range 50a1000 mb, water partial pressure range 0.001a5 mb, absorption path range 16a8500 cm and provided sufficient redundancy. Transmittance spectra corrected for various instrumental error sources were used in an automated single spectrum fit line parameter retrieval based on the Voigt profile. Average gas temperatures were fitted from retrieved water line strengths. From the retrieved Lorentzian line widths of each individual transition the air and self-broadening parameters and temperature exponents, I3air, I3self, nair, nself, or a subset thereof were fitted in an automated procedure. Various methods for validation of data product accuracy and data reduction model as well as comprehensive error analysis were applied. In total 593 I3air, 459 nair and 469 I3self values are reported, uncertainties for I3air are given for reference temperatures 296 and 220 K. Only data are reported where the I3air uncertainty is