1998-2013年新疆艾比湖湖面时空动态变化及其驱动机制

采用1998年9月,2002年9月,2007年9月,2011年9月以及2013年9月多期Landsat数据,利用归一化水体指数模型(NDWI)和修正归一化水体指数模型(MNDWI)提取新疆艾比湖水域面积,研究近年来艾比湖湖面的动态变化。以最大似然分类结果作为标准,验证了用NDWI和MNDWI模型提取面积的精度,得出NDWI模型所提取的湖泊面积更符合实际情况,湖泊总面积从1998年的519.26km²减少到2013年的422.73km²,缩小了18.59%,表明目前艾比湖正在退化,从而促使生态环境受到影响。对5期影像中的艾比湖湖面进行了边界的提取和叠加,利用湖泊面积动态模型研究艾比湖湖面积的动态变化,在此基础上分析了影响艾比湖湖面积变化的驱动机制,近年来随着温度的逐渐升高,降水量呈下降的趋势,加上大量的蒸发作用、径流量变化及沙尘日数等综合作用的结果,导致了艾比湖面积的缩小。多年来艾比湖流域内随着人口数量的增加、耕地面积的不断扩张、牲畜的大量增长,导致需水量逐渐增大,因此也是导致湖面面积减少的主要原因之一。开展艾比湖湖面时空动态变化及其驱动机制研究,对于干旱区湖泊来说具有重要的理论和实际意义。

The spatial and temporal dynamic changes and driving forces in the surface area of ebinur lake from 1998-2013

Lakes are an important resource for developing the economy and have a significant influence on maintaining regional ecological balance. This study used Landsat data from September of 1998, 2002, 2007, 2011 and 2013 to research the dynamic change of Ebinur Lake and its driving forces in recent years. The study used the normalized difference water index (NDWI) model and modified normalized difference water index (MNDWI) model to measure the surface area of Ebinur Lake. Maximum likelihood classification results were taken as the standard and the accuracy was verified with the lake area measurements in the NDWI model and the MNDWI model. Results showed that the NDWI model is more suitable for the actual situation. A total lake area of 519.26 km² in 1998 was reduced to 422.73 km² in 2013. This shrinkage of 18.59% showed that the Ebinur Lake was becoming degraded. Meanwhile, the authors used the ArcGIS 9.3 software to determine the Ebinur Lake boundary and used the dynamic model of lake area to research the change in lake dynamic further. In addition, the team analyzed the driving forces from two aspects: (1)In recent years, with the rising of temperature, precipitation showed a downward trend. In addition, a large amount of evaporation and runoff changes caused the Ebinur Lake area to shrink. Meanwhile, the authors analyzed the relationship between sand-dust days and lake area as well as the dry lakebed area.(2) With the increase in population, the watershed expanding of cultivated land area, and the large number of livestock, water demand is gradually increasing. Therefore, one can conclude that population growth is one of the main reasons that the lake is shrinking. In conclusion, carrying out research on the spatial and temporal dynamic changes and the driving forces in the reduction of surface area of Ebinur Lake has important theoretical and practical significance for the arid zone lakes.