塔里木盆地南缘2000-2013年人工绿洲扩张特点

利用2000、2005、2011、2013年4期MODIS13Q1、Landsat TM/ETM+/OLI遥感影像,基于RS、GIS技术,分别提取土地利用/覆被类型信息,探讨塔里木盆地南缘人工绿洲扩张特点。结果表明:塔里木盆地南缘人工绿洲在2000-2013年不断扩张,各时段扩增来源中,天然绿洲比重不断减小,绿洲-沙漠过渡带比重逐步上升,荒漠比重快速增加。各流域人工绿洲扩张的阶段性与区域性差异明显,且扩增来源结构由于扩张的相对区位不同而异。人口增长、政策引导使人工绿洲不断扩张,并具有阶段性与区域差异性特点。人工绿洲扩张过程中,天然绿洲和绿洲-沙漠过渡带有明显退化现象,使其生态屏障功能下降,威胁到绿洲安全和经济社会的可持续发展。

Characteristics of artificial oasis expansion in south Traim Basin from 2000 to 2013

In the south of Traim Basin, there are a string of oases with beaded distribution, which are the central space of local socio-economic development for thousands of years. However, the arid climate and frequent blown-sand events made the south of Tarim Basin to be a typical area of extreme drought and ecological fragile zone. Since the implement of development strategy in West China, this area vigorously developed the featured horticulture. The continual land development activity made land use/land cover change significantly. Based on RS and GIS technologies, this paper selected four periods(2000, 2005, 2011 and 2013)remote sensing images of Landsat TM/ETM+/OLI data, and used manual visual interpretation to extract boundary of artificial oasis. The paper selected MODIS13Q1 data and adopted NDVI methods to extract boundary of natural oasis and oasis-desert ecotone, then used the spatial analysis function of ArcGIS10.0 to get the transfer matrix of land use types to investigate the characteristics of artificial oasis expansion. It turned out that artificial oasis in the south of Traim Basin showed a continuous increase trend. But the structure of changing source was different at each period:the proportion of natural oasis was decreased, the proportion of oasis-desert ecotone was rose steadily, and the proportion of desert was increased rapidly. To artificial oasis of different watersheds, it showed significant periodical and regional differences. And its structure of amplification source was owing to the relative location of its expansion. The growth of population and policy factors were the main reason why artificial oasis expansion increased and showed characteristics of periodical and regional differences. The degradation of natural oasis and oasis-desert ecotone may induce the retrogression of ecological barrier function, and then threatened security and sustainable development of the oases. Scientific and reasonable management of land use of regional oasis is the common responsibility and important task for research workers and local managers to maintain ecological system security and sustainable socio-economic development of oases in the south Traim Basin.