中国西北地区额济纳绿洲植被盖度与黑河流量的滞后效应研究

干旱区植被生长与地下水的关系是生态水文地质学研究的热点之一。西北干旱地区,由于降水稀少,绿洲是当地人类生存和发展的主要依托。近年来,随着黑河流域中游地区用水量的逐年加大,下游来水量减少,使得下游额济纳绿洲的面积不断减小,湖泊干涸,沙漠化严重,生态环境恶化。由于绿洲植被的生长与水有极为密切的关系,因此,研究河流流量与绿洲植被生长之间的定量关系,对改善黑河流域生态环境、协调用水矛盾和合理配置水资源具有重要意义。将遥感数据与黑河径流量数据相结合,在区域尺度上定量研究额济纳绿洲植被生长与河流径流量的关系。结果表明,绿洲植被对黑河径流以及地下水有很强的依赖关系,而且黑河径流对额济纳绿洲的影响存在一年的滞后期,而地下水则通过这种滞后作用将两者联系起来。

Hysteresis effect of runoff of the Heihe river on vegetation cover in the Ejina oasis in northwestern China

The relationship between vegetation growth and groundwater in arid areas is one of the most actively researched topics in ecohydrology.On account of little precipitation, the oasis is the only form of sustenance for living and economic development, for the local people in the arid areas of northwest China.During recent years, with the increase of water consumption in the middle stream area of the Heihe river basin, the incoming water has decreased gradually and the area of the Ejina oasis in the downstream area has decreased continuously.It has caused lake drying, land desertification, and ecoenvironmental degradation.The vegetation growth of the oasis has a close relationship with the water resources.Therefore, research on the quantitative relationship between the runoff and the vegetation growth has significance in improving the ecoenvironment, and balancing the contradiction of water consumption and reasonable allocation of the water resources in the Heihe river basin.Combined with remote sensing data and runoff of the Heihe river, the quantitative relationship between the vegetation growth of the Ejina oasis and the runoff of the Heihe river has been established from the regional scale in this study.The result indicates that the growth of oasis vegetation depends on the runoff of the Heihe river and the groundwater.The time lag of the impact of the runoff of the river on the vegetation cover of the Ejina oasis is one year, and the groundwater links the vegetation cover and the runoff by this Hysteresis effect.