Remote sensing analysis of land use change and its driving factors in the northeastern Qinghai province, China

摘要

The eastern Qinghai province is located in the transitional belt between the Loess Plateau and the Qinghai-Tibetan Plateau. In this paper, the spatial and temporal change patterns of land use were quantified by visually interpreting remote sensing (RS) data and use geographical information system (GIS). The objectives of this paper were to investigate the land use situation and the change trend of land use during 14 years from 1986-2000 and to understand causes of land use change. Firstly, land use maps were derived from visually interpreting the Landsat TM images with the help of MGE and ARC/INFO 7.11. In the analyzing process, digital maps were overlaid in order to generate land use dynamic map, transition matrix and to calculate rates of conversion. Secondly, the relative change rate model was introduced and calculated. The results showed that there has been a net decrease of 3736.84ha in grassland which was mainly converted to cultivated land. Urban and /or built up land increased by 4.39%, originated from the conversion of cultivated land. At the same time Relative change rates revealed that there were significant differences in quantitative change of land use in every county/city. The trend of land use change was that urban and built-up was expanded, farmland encroached and grassland continuously reclaimed as farmland. In the end, the driving factors of land use change were analyzed. The increasing population pressure and urban expansion and the development of industry were the major driving factors for land use change in the northeastern Qinghai province.