基于MODIS与Landsat 8的艾比湖湿地旱情时空变化及其影响因素分析

对干旱区艾比湖湿地旱情进行多源遥感监测,分析干旱对艾比湖湿地的生态安全与农业生产的影响,为水资源合理配置与干旱预警提供依据。选用2013年5月到2016年5月的MODIS温度和植被指数产品数据反演TVDI指数,并构建二维特征空间,分析土壤水分的时空分布特征,结果表明:TVDI可以有效地反演土壤水分,且精度较高;通过分析,艾比湖湿地土壤水分格局呈现由"极湿润-湿润-正常"面积减少,"干旱-极干旱"面积增加的趋势;在此基础上分析了影响艾比湖干旱变化的影响因素,近年来随着温度升高,风速与蒸发量增加,降水量减少,使艾比湖湿地旱情急剧恶化。利用多源遥感能很好的实现大面积、长时间、高精度的旱情监测,在四年间艾比湖湿地的旱情有所加剧,湖水面积与冰川萎缩变化较为严重,可见艾比湖湿地旱情情况较为不乐观,需加强水资源管理,开展艾比湖旱情监测对于干旱区湖泊生态有重要的理论与实际意义。

Analysis of spatiotemporal changes in the drying of the Ebinur Lake Basin and its influencing factors based on MODIS and Landsat 8 satellites

By using multisource remote sensing data, the drought data of Ebinur Lake wetland in an arid region was extracted and the impacts of drought on the ecological environment and agriculture were analyzed, providing the basis for reasonable management of water resources and the drought warning system. MODIS vegetation and temperature products and Landsat 8 data were used to extract the NDVI and LST in order to inverse temperature and vegetation dryness index (TVDI), and at the same time construct 2-Dimension feature space and analyze the spatiotemporal change of soil moisture. The results showed that the TVDI model has higher precision to effectively inverse regional soil moisture; from 2013 to 2016 in a 4-year span, the Ebinur Lake soil moisture has shown that the wet, normal, and light drought area is decreasing, while the drought and heavy drought area is increasing. In addition, the team analyzed the driving forces in some respects. In recent years, the increase in temperature, population, wind speed, and precipitation showed downward trends, and drought has reduced sharply. It is better to use multisource remote sensing data to efficiently accomplish drought monitoring in a wide area for a long time. The drought in Ebinur Lake wetland intensified during the four years, and the lake water and glacier area are shrinking at a faster rate. The Ebinur Lake regional soil moisture distribution is not improving. In order to protect the regional ecological system, effective local water resources management should be enhanced. In conclusion, carrying out research on the spatial and temporal dynamic changes and the driving forces for drying of Ebinur Lake has important theoretical and practical significances for this arid zone.