Field evidence of appearance and disappearance of the brink line on barchans

- Nucleation of the brink line.
- The disappearance of the brink line.
- The variation of the brink line size.
- All these phenomenon will discuss according to the variability of wind direction and to erosion.

The brink is the highest point of the slip face, while the crest is considered as the highest point of the barchan. It has been reported that the crest and the brink could coincide or separate by a distance with sharp drop of the slope called the brink line. In this work we report field measurements showing longitudinal profiles of barchans from the Moroccan Atlantic Sahara desert. Our measurements show how the brink line nucleates, migrates toward the crest and disappears. In addition, we discuss these results according to erosion rate and variability of wind direction.