Video analysis of Aeolian streamers

Aeolian streamers are elongated flow-aligned features with a large concentration of saltating grains relative to the mean spanwise average concentration. In this respect, streamers are responsible for considerable spatial and temporal variation in transport rates. As part of a larger project to quantity small-scale variability of Aeolian transport at at Jericoacoara, Ceará, Brazil (October, 2011) the scale and behavior of streamers were quantified through video imagery. Three video cameras were deployed in a trianglular array centered on a spanwise array of instruments for measuring the wind field and transport rates. The field of view for the central camera ranged from 15 m at the instrument array to over 200 m at the horizon of the sediment surface. Extracted video images are time-stacked over a number of intervals ranging from 1-120 seconds to identify characteristic path lengths and to quantify the spatial and temporal scales of the streamers. The streamers visible in the time-averaged images have a width of up to 1 m and a length exceeding 50 m, and clearly show the spatial variability of transport.