基于GRACE数据的天山阿克苏河流域水储量变化分析

水储量变化可视为气候变化对水文系统影响的指示器。基于GRACE数据,结合气候数据和冰川积雪数据,分析了近10 a年来阿克苏河流域的水储量变化。研究结果表明:(1)过去10 a间阿克苏河流域的水储量呈递减趋势,减少速率为-0.12±0.85 cm/a,且春季表现为正距平,而秋季表现为负距平;(2)山区冰川退缩和积雪消融是该流域山区水储量减少的主要原因,近半个世纪以来冰川物质平衡为负平衡,同时近十年来积雪面积递减速率为-24 km~2/a;(3)阿克苏河流域的耕地面积的迅速增加导致了地下水过度超采,是绿洲区水储量减少的主要驱动因子。

Study on Water Storage Variations in the Akesu River Basin bBased on GRACE Dataset

The Aksu Irrigation Area, a typical oasis irrigation system in the mid-latitude arid region, is the second-largest irrigation unit in Xinjiang. Understanding the variations of crop water requirement can provide a scientific basis for plantation structure adjustment and water resources management. Based on the Penman-Monteith Evapotranspiration Model recommended by the Food and Agriculture Organization of the United Nations (FAO), this study estimated the temporal and spatial variations of crop water requirement and its sensitivity to meteorological factors and crop structure in the Aksu irrigation area. Results showed that the average crop water requirement of Aksu irrigation area was 586 mm, and it increased significantly during 1960~2015 with an increase rate of 38.43 mm/10a. A significant upward trend of crop water requirement during 1990 ~ 2015 was detected as a combined effects of climate change and evolution of crop structure. Crop water requirement of fruit tree was the largest (up to 829.8 mm), followed by cotton, rice and maize, and water requirement of wheat was the lowest. The crop water requirement was more sensitive to maximum daily temperature and sunshine hours, while less sensitive to minimum temperature, wind speed and water vapor pressure. The crop water requirement increases by 4% when the maximum temperature rises by 2 °C, while it increases by 3.2% when the sunshine hours increase by 10%. The crop water requirement was also sensitive to crop structure. The crop water requirement increases by 12.1% when the proportion of fruit trees increases 10%.