为了揭示腾格里沙漠沙层含水量和水分运移及平衡等科学问题,对甘肃民勤和宁夏中卫不同沙丘进行了含水量研究。结果显示,腾格里沙漠南缘沙层含水量空间变化明显,在垂向上分层清楚,水平方向上流动沙丘的含水量高于半固定和固定沙丘, 沙漠东南缘沙层含水量明显高于西南缘。甘肃民勤沙层含水量高值层段出现在剖面中上部;宁夏中卫毛管水带之上沙层含水量较高,指示沙层水分来自大气降水。研究区沙层水分主要以薄膜水的形式存在,在降水较多的沙漠东南缘出现了沙漠区极少出现的高含量薄膜水。该区沙层水分具正平衡特点,属于沙层水理性质决定的沙漠地区特殊的水分正平衡,这能够较好地解释极端干旱的沙漠区湖泊较多和地下水资源较为丰富的原因。论文还提出了研究区水分运移的两种模式。
In order to reveal sand moisture content, water movement and balance of the Tengger Desert, the moisture content of different types of dunes in Minqin and Zhongwei was studied. The results show that the spatial variation of sand moisture content is remarkable. The layered structure is clear in vertical direction while the moisture content of mobile dune is higher than that of half-fixed dune and fixed dune in horizontal direction, and the moisture content of southeastern edge of the desert is higher than that of southwestern. The phenomena, which the higher moisture content lies the upper part in Minqin and above capillary water sand layer in Zhongwei, indicate the sand moisture mainly comes from meteoric water. The moisture form is mainly film water in this area. There is high moisture content of film water in the southeastern edge of the Tengger Desert, which has more precipitation. The characteristic of sand moisture is special positive equilibrium, which is defined by water physical properties of sand layer. It can correctly explain why there are many lakes and abundant groundwater in the extreme dry desert. This paper also presents two modes of water movement.
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