92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Monday, 23 January 2012: 1:45 PM
Measuring Wake Vortices and Wind Shears in Real-Time with a Scanning Wind Doppler Lidar
Room 239 (New Orleans Convention Center )
Ludovic Thobois, LEOSPHERE, Paris, France; and L. Sauvage and S. Loaec

Measuring and foreseeing wind conditions near airports are crucial issues for air traffic safety. Since aircraft maneuverability is the worst during takeoff and landing phases, strong air movements near airports such as wind shears or wake vortices can have dramatic consequences on aircrafts. These phenomena are nevertheless very different since wind shears are generated by geography around airports, whereas wake vortices are created by aircrafts themselves. Wind shears usually appear in airports located near coasts, valleys, or mountains. These geographical items induce different winds in direction and in intensity depending on meteorological conditions. Wake vortices are generated by all the planes. Size and intensity of wake vortices are directly linked to the flight speed and also by plane characteristics, such as weight and wingspan. Even if strong efforts have been done to study and model wind shears and wake vortices, on-site measurements remain the best way to detect them as they depend a lot on meteorological conditions near airports especially wind and turbulence. Coherent laser radars or LIDARs can be very powerful devices for measuring wind shears on dangerous airports or wake vortices. LEOSPHERE has developed a scanning wind doppler lidar, the Windcube200S for these needs. Deployed on a french airport in the framework of the european project SESAR, this lidar has been used to detect wake vortices and follow them under various atmospheric conditions. Given specific swept scenarios, the Windcube200S has been able to detect the wake vortices of heavy, medium and small aircrafts during takeoff and landing. Wake vortices have been monitored for a period of 30 to 60 seconds that allowed to analyze theirs trajectories and theirs shapes evolution. Several analysis have been achieved in order to determine the influence of the wind conditions on the trajectories of wake vortices. A variety of trajectories have been put in front. Finally, a dedicated post-treatment has been developed for identifying the cores of wake vortices and for calculating theirs circulations.

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