Analysis of land use change in the Manasi oasis of arid region, northwestern China using remote sensing and GIS

Abstract

The objective of the study was to quantify and analyze characteristics of LUCC in the spatial-temporal. Taking Manasi oasis in the north slope of Tianshan Mountains as the study area, we obtained the two date Landsat TM,ETM images of the late 1980s and the early 2000s. Radiometric correction was conducted using not less than 30 ground control points based on 1:500,000 topographical maps. A land use field investigation was carried out in order to have a general understanding to the area. Secondly, Land use maps were acquired by visual interpretation using EDRAS IMAGINE 8.7 and Arcinfo GIS 9.0. The conversion matrix of land use change was calculated to acquire the transition rates of land use change from the late 1980s to the early 2000s.The characteristics of LUCC in the spatial-temporal were studied and analyzed by adopting the land use dynamic degree model, conversion matrix model. Thirdly, landscape indices including landscape percentage (%land), mean patch size (MPS), patch density (PD), area-weighted mean patch fractal dimension (AWMPFD) were selected to quantify landscape pattern change of land use. The results indicated that during the 11 years, the areas of cultivated land, urban-built up, water land and marsh land increased, while those of grassland and forestland, saline and alkaline land and sand land decreased. The grassland was converted to cultivated land and urbanbuilt up. The landscape of the Manasi oasis has become more regularity, continuous and homogeneous. Favorable disturbance of human activity to landscape has made the oasis expansion process larger than the oasis desertification process.