The Study Of Ecological Risk Assessment In Oasis Arid Areas Based On RS/GIS Technology

Ecological risk assessment is a newly developed research field, along with the transformation both of environmental management goal and notion. Regional ecological risk assessment is a method which describes and assesses the possibility and size of adverse effects of eco-system from human activities or natural disasters on the regional scale. Compared with single ecological risk assessment, regional ecological risk assessment more considered the uncertainty of source risk and the spatial heterogeneity of risk receptor, so its evaluation results more objective. Regional ecological risk assessment can be summarized as five steps:landscape type analysis, risk receptor analysis, risk source analysis, exposure and endangers analysis and risk synthetical evaluation.By using "RS/GIS" technology, after processing and analyzing some remote sensing data from landsat TM in2000,2006and2010, the regional ecological risk was carried out in Ganzhou, Gaotai and Linze, which is the typical oasis areas. Considering the special natural environment, social economy and ecological situation of research areas, choose sandy land, gobi, farmland, forest land, grassland, water areas, construction land, saline alkali land and other unused land as the risk receptor. Choose soil erosion, human interference and drought and flood disaster as the main risk sources. And then, analyze and describe the risk sources, including spatial distribution, and probability. Construct comprehensive loss model to calculate the losses after risk receptor be disturbed by risk source. Finally, after the above analysis, complete the comprehensive evaluation. The results show that:the whole ecological risk is medium and low level, with the lower area is mainly distributed in the central of research areas, and from the center in all around, the overall ecological risk level is gradually increasing.The results of regional ecological risk assessment aims to provide countermeasures for the regional ecological risk management, provide suggestions for the region ecological environment improvement and provide guidance for the improvement and maintenance of region ecological environment.