Abstract
The water vapor content in the atmosphere is an important criteria for the validation of predictive results obtained from global scale atmospheric models. Due to its non-homogeneous distribution in the troposphere, both in space and time, the water vapor content in the atmosphere may still be considered today as the largest uncertainty in our understanding of the earth radiation budget. This paper presents new results obtained by Raman lidar measurements as one of the attractive method for long-term continuous observation of the water vapor content in the atmosphere. A powerful pulsed laser beam at 355 nm is emitted and the inelastic back-scatter signals (Raman shift) from nitrogen and water vapor are recorded respectively. The ratio between the water vapor Raman shifted wavelength at 408nm and the nitrogen at 387nm gives a first estimate of the relative water vapor mixing ratio with good vertical resolution. The absolute water vapor vertical profiles are retrieved using an additional in situexternal reference value directly obtained from a local meteorological station. The Raman lidar system, operated at an altitude of 3′580 m above see level in the Swiss Alpine region at the Jungfraujoch research station, is presented, and two typical water vapor vertical profiles obtained in clear sky and in cloudy conditions are discussed and directly compared with radio sounding measurements performed by the Swiss Meteorological Station from Payerne (80 km West). A first estimate of the statistical (signal to noise) and systematic error sources is presented.
Published Version
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