城市建成区周边草地荒漠化遥感监测研究

his paper presents the spatial extent, magnitude and temporal behavior of grassland desertification caused by urban expansion. The selected test site, Huoliguole city, is the grassland city in china, located in the northeast of china. A time-series of Landsat TM images covering a period of 20 years (1987-2006) were used. The built-up area of the city, grassland desertification indicators and the grassland desertification were extracted based on BP neural network and spectral mixture unmixing approach, and the spatio-temporal evolution characteristics were analyzed. The results of our studies indicate that there is a significant increase in urban expansion from 1987 to 2006, and the similar trend was observed in the temporal magnitude behavior of the severe grassland desertification around the built-up area of the city; the severe grassland desertification is always in shape of triangle around the built-up area of the city, and developed to the east quickly with the help of monsoon; there is a positive correlation between the built-up area of the city and the area of severe desertification, so the built-up area of the city can be used as an important assessment and prediction indicator for grassland desertification due to urban expansion.