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Recent desertification has become one of the serious environmental issues. It is important to elucidate mechanisms of the sand erosion on the desert dune with considering the turbulent air flow. In this study, we measured the velocity around the model dune by a two-component laser-Doppler velocimetry system. The relation between the turbulent intensity as well as the mean flow around the dune and the erosion process was discussed. These experiments were carried out with two different height fences. It was found that the shape of the eroded dune surface was roughly parallel to the shear layer with the high turbulent intensities starting from the top offence. The effects of the fence on the erosion as well as anti-erosion were significant.