干旱区生态环境知识资源中心

Starting with the change of the land cover and the landscape patterns as well as the cold-island effect of the oasis, the temporal and spatial variation and the stability of the oasis of the alluvial-diluvial-fan/alluvial-plain type in the Sangong River watershed are researched by using the theories and methods of GIS, RS and landscape ecology based on the aerial photos in 1978 and 1987, the TM images in 1998 and the meteorological and hydrological data of the watershed. The results show that ( i) the land cover of the whole oasis changes rapidly in a big amplitude, and there is an obvious temporal variation; (ii) during the period of 1978-1987, the diversity and the variation of the oasis landscapes were increased but the stability of the oasis was decreased, the diversity of the oasis landscapes, however, has been decreased, but the stability has increased since 1987; (iii) the cold-island effect of the oasis in the Sangong River watershed has been gradually increased since the 1960s, which reveals that the stability of the oasis has been obviously increased viewed from the angle of climate.