Monitoring of environmental change in Dzungar Basin by the analysis of multi-temporal satellite data sets

Abstract

The purpose of this study is to investigate the environmental change and its cause in Dzungar Basin of the Central Asia through an analysis of land cover condition and its change using new created multi-temporal satellite data sets. The multi-temporal and multi-stage satellite data sets were firstly produced by using high spatial resolution satellite data and wide observation satellite data. Next, fluctuations of the past about 50 years in the water area of closed lakes were investigated in detail by analyzing the data sets. Changes in the irrigated agricultural lands along the inflow rivers to the lakes, and the snow and glacier area covering the mountainous district were also investigated. A change in the long-term scale of a lake was estimated by using the DEM data based on ASTER image with the historical record of terraces distributed around the former water area of the lake. Finally, natural and artificial causes of the change in the object area were examined by comparing the satellite data analysis results with meteorological data and auxiliary sources. The study results showed most of closed lakes in Dzungar Basin have shown the rapid shrinkages in the past about 50 years. However, it changed into the remarkable expansion of the water area since 2002. As for a cause of the change in closed lakes due to the analysis result for changes in the irrigated agricultural lands, snow and glacier extents, it was shown that the influence of human activities such as development of irrigation lands was bigger than the one caused by natural fluctuation based on the climate change.