鄂尔多斯盆地风沙滩区凝结水形成机理的实验研究

Experimental Study on the Formation Mechanisms of Condensed Water in a Wind-blown Sand Area in the Ordos Basin

利用自制的笼屉式蒸渗仪,在鄂尔多斯盆地包气带水盐运移原位试验场开展凝结水实验研究。以凝结水试验观测数据为基础,讨论鄂尔多斯盆地包气带中水汽运移过程和凝结水形成过程。结果表明:一天中水汽运移有水汽从大气运移至包气带、水汽从包气带运移至大气、水汽向地面聚集和水汽从地面向大气和包气带扩散4个过程;鄂尔多斯风沙滩区0～10 cm土层中都有凝结水,但凝结量主要集中在地表2 cm,凝结水最大量的形成深度在7～9 cm。并初步探讨了凝结水的形成机理。

A home-made cage-shaped lysimeter was used to carry out an experimental study on condensed water in an in-situ testing field in the Ordos Basin aimed at water-salt migration in the zone of aeration of soil.Based on the observation data of condensed water experiment,the water vapor migration process in the zone of aeration and water condensation process in the Ordos Basin are discussed.The results show that the temperature difference between the atmosphere,ground surface and zone of aeration is the driving force of forming condensed water;the daily vapor migration can be divided into 4 stages：water vapor is migrated from the atmosphere to the zone of aeration, vapor is migrated from the zone of aeration to the atmosphere,vapor is condensed over the ground surface,and vapor is diffused from the ground surface to the atmosphere and the zone of aeration;there is condensed water around a soil layer of 0～10 cm in depth in the Ordos Basin,but the accumulation of condensed water occurs mainly at soil depths of 2 cm and 7～9 cm,especially at the soil depth of 7～9 cm;the effect of vegetation on atmospheric condensed water is not so significant in the wind-blown sand area in the Ordos Basin.Moreover,the formation mechanism of condensed water is preliminarily researched.