title: Spontaneous Rayleigh-Brillouin scattering of ultraviolet light in nitrogen, dry air, and moist air.
abstract: Atmospheric lidar techniques for the measurement of wind, temperature, and optical properties of aerosols rely on the exact knowledge of the spectral line shape of the scattered laser light on molecules. We report on spontaneous Rayleigh-Brillouin scattering measurements in the ultraviolet at a scattering angle of 90 degrees on N(2) and on dry and moist air. The measured line shapes are compared to the Tenti S6 model, which is shown to describe the scattering line shapes in air at atmospheric pressures with small but significant deviations. We demonstrate that the line profiles of N(2) and air under equal pressure and temperature conditions differ significantly, and that this difference can be described by the S6 model. Moreover, we show that even a high water vapor content in air up to a volume fraction of 3.6vol.% has no influence on the line shape of the scattered light. The results are of relevance for the future spaceborne lidars on ADM-Aeolus (Atmospheric Dynamics Mission) and EarthCARE (Earth Clouds, Aerosols, and Radiation Explorer).
authors.affiliation: Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany. Benjamin.Witschas@dlr.de
authors.forename: Benjamin
authors.initials: B
authors.lastname: Witschas
authors.forename: Maria O
authors.initials: MO
authors.lastname: Vieitez
authors.forename: Eric-Jan
authors.initials: EJ
authors.lastname: van Duijn
authors.forename: Oliver
authors.initials: O
authors.lastname: Reitebuch
authors.forename: Willem
authors.initials: W
authors.lastname: van de Water
authors.forename: Wim
authors.initials: W
authors.lastname: Ubachs