1. Principles

1.1 Mie and Rayleigh diffusions

The techniques currently used in on-board laser anemometry systems use particles naturally present in the atmosphere.

Light is scattered by these particles according to a law that depends on their diameter.

If the particle diameter is small in relation to the wavelength of the emitting light, we find ourselves in the Rayleigh scattering regime, also known as molecular scattering. If the diameter of the particles is of the same order of magnitude as the wavelength of the emitting light, we're in the Mie scattering regime.

Natural aerosols are good tracers because their thermal agitation is negligible compared with the measurement accuracies required (a few cm/s), which is not the...