R.: Pressure-broadening coefficients and line strengths of H2O near 1.39µm: application to the insitu sensing of the middle atmosphere with balloonborne diode lasers

Abstract Since 1998, we have developed two balloonborne diode laser spectrometers, SDLA and micro-SDLA, to yield in situ concentration data of H 2 O in the middle atmosphere by absorption spectroscopy in the 1.39-mm spectral range. In this paper, we revisit the molecular parameters, line intensities and pressurebroadening coefficients, for several lines of the n 1 +n 3 and 2n 1 bands, which are useful for the monitoring of atmospheric H 2 O. The new values are thoroughly compared to existing molecular database and previous determinations. Calculations are performed to yield the pressure-effect coefficients: the theoretical model is described and the ab initio predictions are compared to laboratory measurements achieved with a laser diode spectrometer. The improvement in the H 2 O monitoring obtained with the new set of molecular data is evaluated directly from vertical H 2 O concentration profiles.