1990-2019年咸海水量平衡及其影响因素分析

咸海地处中亚,气候和人类的双重影响下湖面急剧萎缩引发区域生态危机,定量解析其水量平衡互动关系及影响因素对咸海地区水资源管理和生态保护有重要意义.基于1990-2019年密集时序Landsat影像、T/P卫星、Jason1/2测高卫星及咸海数字测深模型(DBM),提取近30年咸海面积、水位变化信息,重建咸海水位-面积-库...

Analysis of water balance in Aral Sea and the influencing factors from 1990 to 2019

The Aral Sea is located in Central Asia. Under the impact of climate change and human activity, the lake surface has shrunk sharply and triggered a regional ecological crisis. It is of great significance to study the changes of water balance and their driving factors for water resources management and ecological protection in the Aral Sea region. Based on the dense time-series Landsat imagery from 1990 to 2019, T/P satellite, Jason1/2 altimetry satellite, and digital bathymetry model (DBM) of the Aral Sea, time serieses of the Aral Sea area and water level in the past 30 years were extracted, to reconstruct the Aral Sea water level-area-volume capacity curve and explore the characteristics of the Aral Sea volume changes. A water balance equation was also established to quantitatively analyze the spatiotemporal changes of the water balance elements in the study area and their impacts on the Aral Sea volume. The results show that the water volume decreased by 2271.6×10⁸ m³ (about 75.15%) with an average decreasing rate of 78.3×10⁸ m³/a from 1990 to 2019 in the Aral Sea, a similar variation trend was detected in the South Aral Sea. Except for the minimum value in 1999, the water volume in other years showed a fluctuating and rising state in the North Aral Sea. By 2019, the water level had returned to the level of 1984. Since the 1990s, the inflow from the Amu Darya River to the Aral Sea showed a decreasing trend, and the spatiotemporal differences in the water balance structure of the South and the Nouth Aral Sea are significant. As the Aral Sea continues to shrink, and water evaporation continues to decrease, the regional water expenditure and income ratio decreases from 2.46 in 1990 to 0.87 in 2015. In recent years, the groundwater in the South Aral Sea changed from deficit to surplus, and the water area changed into a relatively stable state. The evapotranspiration of the North Aral Sea increased with the increase of the water area. Since the early 1990s, the water income has exceeded its expenditure, regional groundwater has bacome surplus, and the lake water level has been constantly rising. On the regional scale of the Aral Sea, the inflow and evaporation are the main factors affecting the change of the water volume in the Aral Sea. On the catchment scale, climate change and human activities jointly affect the inflow of the Aral Sea. The inflow of the South Aral Sea is significantly correlated with the runoff from the upper Amu Darya River and the cultivated land area of the basin, while the inflow of the North Aral Sea is mainly correlated with the runoff from the upper Syr River.