干旱区生态环境知识资源中心

The Saharan and Sahelian regions are a very important source of dust which amply contributes to the atmospheric dust load. Till now, appropriate measurements on the mechanisms of wind erosion have been very scarce. In 1984, a preliminary study allowed to investigate a possible relationship between the mineralogy of dust and that of surrounding soils along a North-South transect through the Sahara. Three sites have been selected as possible dust province and, on each site, dust samples were collected by air pumping on a mast and soils were sampled as far as 10 or 20 kilometers from the mast. Some available results of this work are given here. In November 1989, a fourth site has been selected in the Sahel and a sophisticated apparatus has been used in order to study (1) the soils, the state of ground surface and the plant cover, (2) the roughness (3) the drag velocity (4) the turbulence, (5) the atmospheric dust load and dust composition (6) the wind velocity (7) the light extinction and (8) extrapolation by remote sensing (dust cloud, soils, vegetation cover and land use).