Detection of land Use / Cover Change in the Upper Reaches of the Yellow River by Remote Sensing and GIS: A Case Study

摘要

In recent years, the ecological environment in the upper reaches of the Yellow River has been degrading due to natural and human factors. Ecological environmental problems such as grassland degeneration, desertification (including mainly sand dunes and sand sheets) and water erosion have seriously affected the regional economical sustainable development. In order to protect and recovery the ecological environment in the upper reaches of the Yellow River, it is important to detect of land use/cover change with remote sensing and GIS. The region around Longyangxia reservoir was chosen as a study site, which is one of the most seriously ecological environmental degraded regions in the upper reaches of the Yellow River. Based on the analysis of the multi-temporal and multi-spectral Landsat TM data with GIS, the land use/cover change was detected for the period between 1987 to 1996. This showed: (1). The land use types mainly are animal husbandry and rainfed agriculture. The structure of land use is simple and unreasonable. Grassland has degraded seriously from 1987 to 1996, resulting in desertification and a reduction in land productivity. (2). The desertified land has increased accounting for 71.5% of total study area, among which the very severe, severe, on-going, and potential sandy desertified lands are 10.9%, 1.3%, 10.3% and 49%, respectively. Desertification has accelerated from 1987 to 1996 with an average spreading rate of 21km~2 per year. It is necessary and urgent to combat desertification and protect ecology environment in the upper reaches of the Yellow River.