Scaling and distribution laws in aeolian sand transport

International audienceWe report on wind tunnel measurements of the saltation length in aeolian sand transport. Using both particle tracking techniques and innovative sand trap, we were able to extract key properties of the saltating particle trajectories. We find in particular that the distribution of the saltation length is almost invariant with the wind speed and exhibits a long-tail statistic that can be well approached by a log-normal law. This long-tail statistic is shown to be intimately connected to the collision process of the saltating particles onto the sand bed (the so-called "splash" process"). The velocity distribution of the resulting ejected particles is indeed shown to obey as well a log-normal law. As a conclusion, an accurate description of the saltating particle properties requires to go beyond the classical Gaussian approximation and account for the long tail statistics