The research task group NATO SET-304 Modelling, measuring and mitigating optical turbulence (M3T) conducted a field trial at the ONERA Le Fauga-Mauzac center near Toulouse, France, from October 10th to 15th, 2022. Turbulence characterization experiments were performed by imaging an array of light-emitting diodes (LEDs) at a distance of 0.2 km. The refractive index structure parameter πΆπ2 was calculated from differential angle-of-arrival fluctuations (DAoA) for pairs of LEDs. A large area scintillometer was also used, with good correspondence between the two sensors. The use of multiple pairs of LEDs in the DAoA-method provides error measures for the πΆπ2-measurements and allow for the study of spatial variability. Fluctuations of πΆπ2 occurring on timescales of the order of seconds have been investigated. As the temporal variation was consistent over independently analyzed rows of the LED array, it can be concluded that they exist for the local path. Statistics of the measured parameter and correlations to other parameters, such as atmospheric refraction effects, solar insolation, and temperature variations with height above ground, are reported.
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