研究戈壁地表土壤颗粒粒度特征及空间变异可为戈壁地区风蚀监测、评价及制定科学的防沙治沙对策提供参考。以吉兰泰盐湖西北部的堆积型细砾质戈壁为研究对象，基于数字图像技术计算了地表不同粒级颗粒的质量分数，并分析了颗粒空间变异特征。结果表明，图像处理技术提取戈壁地表土壤颗粒的效果较好，3个粒级颗粒质量分数总和为93.12%，粒径>0.84 mm、0.84 ~ 0.42 mm和<0.42 mm颗粒质量分数分别为69.81%、14.99% 和 8.32%，变异系数分别为14.12%、40.02% 和55.06%，变异函数模型分别为高斯模型、高斯模型和指数模型，空间异质性尺度分别为632、691和1 875 m。3个粒级颗粒均呈斑块状分布，且C/(C₀+C) 介于72.79% ~ 79.37%，说明结构因素和随机因素共同影响戈壁地表颗粒的空间分布格局，但结构性因素(戈壁形成过程、地势、风蚀及植被分布格局等)是造成颗粒分布格局差异的主要驱动力。

The grain size characteristics and spatial distribution of topsoil particles could provide references for the monitoring and evaluation of surface wind erosion. The stacked fine gravel Gobi in the northwest of Jartai Salt Lake was selected as the research objective. Based on the digital image processing technique, the percentage contents of different size particles were obtained for the Gobi surface. The spatial heterogeneities of different size particles were analyzed through both classical statistics and geostatistics. The results showed that the digital image processing technique was an effective approach to extract the information of surface particle composition, the total percentage of three size particles of non-erodible, semi-erodible and high-erodible was 93.12%, the mean contents of them were 69.81%, 14.99% and 8.32% with the variation coefficients of 14.12%, 40.02% and 55.06%, respectively. The variation functions of non-erodible and semi-erodible particle contents were classified as Gaussian model, while that of high-erodible particle content as Exponential model. The spatial heterogeneity scale of the three size particles were 632 m, 691 m and 1 875 m, respectively. All the above three indices indicated that the smaller the particle size, the larger the spatial variability. All the three size particles were distributed as patches, and the value of C/(C₀+C) varied from 72.79% to 79.37%, indicated that the spatial pattern of surface particles of Gobi was the combined effect of structural factors and random factors, but the structural factors, such as the forming process of Gobi, terrain, the distribution of wind erosion and vegetation, were the dominant driving forces of the spatial distribution of surface particles.

S158.2

国家自然科学基金项目(51769019，41471151)资助。