|Other Abstract||The evaluations of land-use and land-cover changes (LUCC) in the arid region was scarcely quantified before 1980s due to the unavailability of data, resulting in our little knowledge of the effects of LUCC on climate change and carbon/water cycle in that period. In this study, we investigated the evolution of Sangong river basin oasis since 1950s by using seven land cover maps derived from black-and-white aerial photographs (1958, 1968 and 1978), color-infrared aerial photograph (1987), Landsat TM imagery (1998), SPOT (2004) and Landsat OLI images (2014). To present LUCC in urban, we divided urban land surface into impervious surface area (ISA), and pervious surface area (PSA). Besides, both annual variation and seasonal variation of surface heat environment based on land surface temperature (LST) was retrieved by Landsat TM/OLI during the period of oasis expansion and urbanization were analysised. Results show that:
(1) Since 1950s, the oasis area consecutively increased to 162 km2. Under the background of "mass production movement by Xinjiang Production and Construction Corps" and "agricultural modernization", 1950s and 2000s were the most essential periods. Two basic management modes, "local mode" formed by the local governments and "farm management mode" developed by Xinjiang Production and Construction Corps, together promote oasis evolution with various LUCC stages. Oasis expanded by shrinking of the peripheral desert landscapes which are dominated by haloxylon community and tamarix community. The evolution of modern oasis during 1950s-2004 shows common features of most arid oasis, while the period during 2004-2014 is characterized by importing large-scale inter-basin water diversion or some new water sources.
(2) The impervious surface significantly increased during 2004 and 2014, and the built-up expanded 1.5 times. The expansion of impervious surface in the new urban area was mainly manifested in the area expansion. The main performance of the old urban area was the increasing of the impervious surface abundance, the bare soil abundance was significantly decreased. Thus there may be a large area transformed from bare soil to ISA.
(3) The land surface temperature (LST) spatial distribution showed hot-cold-hot pattern from city center to desert. This spatial pattern was more notable in summer and autumn on season level, more obvious in 2014 than 2004. In annual variation of the LST, the strength of the cold island of oasis and the hot island of urban showed an increasing trend. The LST difference between old urban area and new urban area maybe was related to the difference of abundance in land surface components, but mutual influence mechanism still needs to be further discussed.|