The impact of climate change and human activities on the Aral Sea Basin over the past 50 years

摘要

The destruction of the Aral Sea area constitutes one of the world's most infamous ecological disaster. However, the retreat of the Aral Sea has slowed down in recent years and the underlying reasons are not reported. In this work, based on the extreme-point symmetric mode decomposition (ESMD) method and the multiple linear regression model, we analyzed the changing of the Aral Sea from 1960 to 2018, and detected the time for slowdown of retreat, then explored the driving forces. The results show that the Aral Sea retreated rapidly from 1960 to 2004, and the shrinking rates of water surface area, water volume and water level were 1087.00 km(2)/year, 25.07 km(3)/year, and 0.56 m/year, respectively; the retreat has slowed since 2005, with the shrinking rates being 760.00 km(2)/year, 2.86 km(3)/year, and 0.38 m/year, respectively. At the same time, the area of water bodies surrounding the Aral Sea increased due to the agricultural drainage water. The oscillation periods of water level in the Aral Sea are 2.1a, 7.6a and 29.5a, of which 29.5a is the main period of oscillation. The trend residual RES indicates that water level shows a non-linear downward trend, and the degree of fluctuation has decreased significantly after 2005. The impact of human activities on the Aral Sea is more significant than that of climate change. Overall, the increased upstream runoff, reduced water withdrawal, and rise in water delivery to the Aral Sea has led to a slowing down of the sea's notorious shrinkage. The findings provide a scientific reference for the management and protection of the Aral Sea.