沙坡头地区地形对凝结水形成特征的影响

以沙坡头地区经草方格沙障固定的典型流动沙丘作为研究对象，采用PVC管手动称重法和布板法（CPM—Cloth-Plate Method）对该区不同地形位置凝结水的形成特征进行了研究。结果表明：地形作用下凝结水的形成量和形成间期均表现为中等空间异质性；不同坡向凝结水形成量符合经典的水汽对流模型，丘间低地凝结水形成量最高，迎风坡凝结水形成量高于背风坡，具体表现为：丘间低地>西面向坡>北面向坡>丘顶>南面向坡>东面向坡；同一坡向不同坡位处凝结水形成量表现为：坡脚>坡中>坡顶；坡度与凝结水形成量呈负的线性相关关系，随着坡度的增加，凝结水形成量逐渐减少，垂直坡面上凝结水形成量仅为水平面的一半。这说明地形是影响干旱区凝结水形成特征的重要因子。

Influence of Topography on Formation Characteristics of Hygroscopic and Condensate Water in Shapotou,Ningxia, China

The formation characteristics of hygroscopic and condensate water for different topographic positions were observed using the PVC pipes manual weighing and CPM method in the typical mobile dunes fixed by straw checkerboard barriers in Shapotou, Ningxia, China. The results indicated that the formation amounts and duration of hygroscopic and condensate water showed moderate spatial heterogeneity at the influence of topography. The formation amounts of hygroscopic and condensate water at different aspects conformed to the classical convection model, in which the hygroscopic and condensate water amounts were the highest at hollow, and windward aspect got more water than leeward aspect, the hygroscopic and condensate water amounts at different aspects were expressed as: hollow>western-faced aspect>northern-faced aspect>hilltop>southern-faced aspect>eastern-faced aspect. The hygroscopic and condensate water amounts at different slope positions for every aspect were as follows: the foot of slope>middle slope>hilltop. A negatively linear correlation was got between slope angles and hygroscopic and condensate water amounts, hygroscopic and condensate water amounts decrease gradually along with the increase of slope angles, the amounts of hygroscopic and condensate water at the vertical aspect were only half of horizontal aspect, which indicated topography were important influence factors for the formation of the hygroscopic and condensate water in arid area.