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Study on spatio-temporal changes of land-use at arid oasis city based on remote sensing in 30 years

Land-use changes of oases city in Xinjiang played a significant role in the ecological stability and economic development of the arid regions in the Central Asia. Urumqi was a typical oasis city of the temperate zone in the Northern Slope Economic Zone of Tianshan Mountain. Based on Landsat MSS of 1972, Landsat TM of 1990 and 2006, it got three periods of land-use data and six land-use types (cropland, forestland, grassland, water, urban land, and unused land) by object-based approach of land-use classification. Under the support of Geographic Information System (GIS), it calculated the transfer matrix of land-use from 1972 to 2006, analyzed the spatial-temporal characteristics of land-use changes, and explored the interaction between these changes and oasis environment in Urumqi. The result indicated that urban land dramatically increased by 281.89 km2; but unused land and cropland area relatively decreased by129.49 km2 and 169.31 km2, respectively. The area of water, forestland and grassland hadn't changed much during these years. In spatially, the expansion of urban land in Urumqi was in the northeast and northwest regions with limited to the Tianshan Mountains. These land-use changes had resulted in environmental problems in the arid regions (e.g. land degeneration, soil corrosion, water pollution and air pollution).