Characteristics of the lower layer of sandstorms in the Minqin desert-oasis zone

By measuring the sand-dust flux, vertical deposition, and the wind velocity throughout 19 sandstorms in the Minqin region, we quantitatively analyzed the horizontal distribution and vertical variation in sandstorm characteristics under different land cover conditions. The effect of different land cover on mitigating sandstorms was also investigated. The results indicated that, in the surface layer ranging from 0-50 m, the intensity of sand-dust horizontal flux and concentration of sand-dust decreased with the increase of the height in the desert and the edge of oasis, whereas the two physical quantities increased slightly with the increase of the height in the oasis. The two physical quantities obey power function well under all three cover conditions. Moreover, in the desert and at the edge of oasis, the sand-dust vertical deposition decreased with the increase of the height. But a partial unimodal distribution at the oasis site and the maximum deposition occurred at the height of 9 m, which corresponds to the middle height of farmland protection forest. The annual flux that passed through a section of 1 m in width and 50 m in height was 9169 kg in the desert, 5318 kg at the edge of oasis, and 2345 kg in the oasis. And the annual fluxes at the edge of oasis and in the oasis are 42% and 74% less, respectively, than that in the desert. This implies that the wind break forest significantly reduced the intensity of sandstorms.