UFR de Physique

Propositions de stages en laboratoire -- M2

Les offres sont actualisées en mai. Par exemple, les offres de stages pour l'année universitaire 2015-2016 seront mises en place en mai 2015, les offres de stages pour l'année universitaire 2016-2017 seront mises en place pour en mai 2016, etc.

Observation of amospheric turbulence using Doppler lidars

  • Option International « Atmospheric Environnement » du parcours Lumière-Matière
  • Laboratoire: Laboratoire de Physico-Chimie de l'Atmosphère (LPCA)
  • Responsable du stage: DIEUDONNÉ Elsa (elsa.dieudonne@univ-littoral.fr, 03.28.65.82.70)
  • Co-responsable(s): Hervé DELBARRE
  • Mots clés: remote sensing ; Doppler lidar ; atmospheric dynamics ; turbulence
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The development of wind energy over the last 15 years has been accompanied by a rapid evolution of Doppler lidar technology, for wind measurement. These instruments now have a high spatial and temporal resolution, able to resolve the small-scale turbulent structures existing in the atmospheric boundary layer. These structures, and more generally atmospheric turbulence, impact the dispersion (or stagnation) of pollutants and thus the occurrence of pollution peaks. To assess the impact of atmospheric turbulence on pollutants dispersion, turbulence must be characterized by a set of parameters (turbulent kinetic energy, variances of the wind components, momentum flux…). So far, these parameters are measured in-situ using ultrasonic anemometers, however, the resolution of Doppler lidars is now sufficient to consider a remote observation. This is a particularly promising technique as it will allow to measure the profile of the turbulent parameters in the whole boundary layer using a single instrument, whereas it is currently necessary to use a mast equipped with several anemometers, that generally does not allow to go above a few dozens of meters. The LPCA possesses two Doppler lidars of the last technology, including one equipped with a scanning system allowing to orient the beam in all directions. The purpose of this training period is to test different measurement strategies (combinations of several beam directions) proposed in the scientific literature for measuring the turbulent parameters, and validate the results by comparison with the observations of a sonic anemometer. The trainee will thus participate in the deployment of the instruments on the field and then analyze the data, based on existing algorithm or on new programs that he/she would have written.