影响西北沙漠绿洲水均衡的两种人为因素

Two human factors affecting water balance in desert oases of northwest China

从宏观尺度上用遥感方法分析了天然绿洲的时空变化规律。以额济纳绿洲与和田绿洲为例,探讨了绿洲变化的原因,认为绿洲退化的动因都是人类的开发活动所导致的水均衡失调;以量化方式区分出绿洲退化的2类基本原因,即上游来水量的不断减少和过度农田开发导致的灌溉用水量与无效蒸发量增加。

The remote sensing technique is used to trace the developing courses of natural oases on the macro-scale. Two cases, Erjina Oasis in western Inner Mongolia and Hetian Oasis in southern Xinjiang,are studied,and the chief factors leading to oasis alteration are analyzed. It is thought that water balance in the deserts of northwest China has been broken by human developing activities on the oases. With statistical data,it is proved that the degradation of Erjina Oasis is due to reduction of water quantity from the upper stream of the Heihe River and the degradation of Hetian Oasis is caused by the increase in irrigating water and meaningless evaporating water induced by excessive farmland developing.