Spatial-temporal variations and their dynamics of the saline lakes in the Qaidam Basin over the past 40 years

The saline lakes in the Qaidam basin, providing numerous saline mineral resources to the development of China's western region have changed greatly in recent decades. Understanding the spatial-temporal variations of the saline lakes for exploring the dynamics of those changes is not only essential for sustainable development of the region, but also is of significance for scientific studies. By using multi-temporal Landsat and HJ-1A/1B remote sensing data, this study focused on detecting the spatial-temporal variations of the saline lakes concerning with their extent changes with the influence of climate and human activities in the Qaidam basin from 1973 to 2014 based on the normalized difference water index (NDWI) and maximum likelihood supervised classification techniques. The results indicated that most of the saline lakes studied in this paper across the study region had experienced great changes over the past 40 years, and each saline lake differed considerably on extent. The runoff supplies from the surrounding rivers and the large-scale saline resource exploitation were considered as direct reasons for the saline lake extent changes, in which climatic changes characterized by the increase of temperature and slight decrease of precipitation over the region had significant impacts on the lake area variations directly or indirectly.