Abstract: Desert-oasis ecotone plays an important role in combating sand disasters. By taking the patch vegetation area of desert-oasis ecotone in the middle reaches of the Heihe River as the study area, were observed the data of wind erosion and deposition continuously from 2012 to 2015. The intensity of wind erosion and deposition was selected as an index, and was employed to analyze the semi-variance function and spatial distribution of wind erosion and deposition. The results show that the sand movement changed from wind erosion to wind deposition during the observation period, but the specific date of the conversion was uncertain, which couldn't be judged only by the frequency and mean of intensity of wind erosion and deposition. The semi-variable function models of intensity of wind erosion and deposition from 2012 to 2015 were all linear models, and its nugget coefficients changed between 0.8508 and 0.9616 with the characteristic of strong variations, which was caused by the random factors, such as wind, precipitation, animal's movement, human disturbance, etc. The spatial pattern of intensity of wind erosion and deposition was mainly displayed as mild and micro-degree status, and wind erosion area decreased but wind deposition area increased. The spatial pattern change of wind erosion and deposition was correlated with regional terrain, vegetation coverage, meteorological factor, etc.

Key words: desert-oasis ecotone, intensity of wind erosion and deposition, semi-variance function, spatial pattern