Land use and land cover change monitoring in the Source Region of Yellow River by remote sensing technology

The Source Region of Yellow River locates in the northeast of Qinghai-Tibet Plateau with an area of 131419 km², which is especially sensitive to global warming because of its high elevation and cold environment. To assess the land use and land cover changes from 1975 to 2005, we employed remote sensing and GIS technology to monitor the area of land use and land cover at four times (1975, 1990, 2000, and 2005). The data sources included Landsat multi-spectral scanner (MSS) images acquired in 1975 with an 80-m spatial resolution, Enhanced Thematic Mapper (ETM+) images acquired in 2000 with a 30-m resolution, and Thematic Mapper (TM) images acquired in 1990 and 2005 with a 30-m spatial resolution. The monitoring result shows that, under the influence of global warming and human activities, the Source Region of Yellow River experienced an overall environmental degradation between 1975 and 2005. The environmental degradation includes deforestation, grassland degradation, cultivated land increasing, sandy land expansion and wetland shrinking.