基于GIS的乌梁素海东岸上游地区水土流失动态变化研究

A Study of Dynamic Changes of Soil and Water Loss in Upstream Area of East Wuliangsuhai Coast Based on GIS

利用1985,2000和2011年遥感影像和DEM数据,在GIS软件平台下计算了乌梁素海东岸上游地区各水土流失因子,最终得到3期水土流失强度并进行分级。定量地研究了水土流失强度面积的时空变化和各类型水土流失强度的动态转换,并运用马尔可夫模型预测水土流失动态变化。结果表明,1985—2000,2000—2011年水土流失逐年加剧,27a来微度水土流失面积减少了717.43km2,而强烈水土流失面积增加了389.23km2。水土流失加剧的区域主要集中于乌梁素海东部沿岸、中部农牧区以及风沙区,乌拉山、色尔腾山的水土流失已经逐步减弱。2011—2022年微度和轻度水土流失面积仍在减少,强烈和极强烈水土流失面积仍将扩大。通过研究乌梁素海东部上游水土流失强度的演变,可以更好地掌握区域水土流失时空变化规律,为水土保持与生态环境建设提供科学依据。

The study used remote sensing images and DEM data of 1985, 2000 and 2011 to calculate various factors for soil and water loss in the upstream area of East Wuliangsuhai coast based on GIS. Soil and water loss in the three years was classified according to the calculated result. A quantitative study was performed for temporal-spatial variations of soil and water loss area, as well as dynamic conversion of various types of soil erosion degree. Dynamic changes of soil and water loss were predicted with the Markov model. Results indicated that from 1985 to 2000 and 2000 to 2011, soil and water loss increased year by year. For 27 years, the slightly losing area decreased by 717.43 km2 , and the strongly losing area increased by 389.23 km2. The intensified soil and water loss area mainly concentrated on East Wuliangsuhai coast, central pastoral area and sandy area. By contrast, soil and water loss gradually decreased in the regions of Ural Mountains, Serteng Mountains and Zhashitai Mountains. Predictably, from 2011 to 2022, the slightly and mildly losing areas will continue to decrease, and meanwhile the strongly and heavily strongly losing areas will increase accordingly. The evolution of soil and water loss in the upstream area of east Wuliangsuhai coast was fully discussed for better understanding of temporal-spatial variations of soil and water loss. The study provides a scientific basis for soil and water conservation and ecological construction.