RESUMO
Since 1989 Service d'Aéronomie du Centre National de la Recherche Scientifique has used an incoherent Doppler lidar technique for wind measurements in the atmosphere. A new-generation Rayleigh-Mie Doppler lidar has been designed and is currently operated at the Observatoire de Haute Provence (France). We give a detailed description of this instrument and highlight two important upgrades leading to quasi-simultaneous and absolute measurements of the wind from approximately 8 to 50 km altitude. The possible sources of error are identified and quantified in terms of accuracy in the wind determination. Experimental results are given in detail, and a validation of the measurements is performed with the help of ancillary data. A first climatological description of the mean wind is briefly reported.
RESUMO
A theoretical and experimental study is conducted for the direct-detection Doppler Lidar developed by the Service d'Aéronomie du Centre National de la Recherche Scientifique. Thanks to a specific design, the double-edge technique that applies primarily to Rayleigh scattering can also be employed in presence of aerosols backscatter. We focus on a careful estimate of the particle-induced error on the wind measurements. With a theoretical model for the Fabry-Perot interferometer and two sets of calibration measurements, the true spectral properties of the interferometer and the calibration curves are recovered. Furthermore, the particle-induced error is estimated for varying values of the scattering ratio at 532 nm. When applied to real atmospheric signals, this error is shown to be negligible. A comparison between ancillary data and the wind and backscatter ratio as retrieved from the Doppler lidar signals confirms our estimate.
