沙坡头地区土壤水分吸湿凝结的动态观测与理论计算

DYNAMIC MEASUREMENT AND THEORETICAL CALCULATION ON WATER ABSORPTION AND CONDENSATION OF SANDY SOIL IN SHAPOTOU REGION

采用实际观测与理论计算相结合方法研究了沙地表层土壤吸湿凝结水量及其变化过程。沙土水分吸湿凝结过程可分两个阶段：第一阶段是由沙土自身物理性质决定的分子凝结过程，所吸收水量主要受温度和湿度影响，最大不超过沙土最大吸湿水量；第二阶段是由近地面微气象条件决定的水分凝结过程，所吸收水量受空气水汽压、地面温度和地表可利用能量的影响。采用能量平衡和空气动力学综合方法计算沙地吸湿凝水量及其动态变化，与实测值相比结果合理，方法是可行的。

The process and amounts of moisture absorption and water condensation in the surface shallow layer of sandy soil are studied preliminarily by the method combining field measurement with theoretical calculation. The results showed that the formation process of water absorption and condensation in sandy soil is composed of two stages. The first one is the process of water molecular absorption determined by the physical properties of sandy soil. The amounts of water absorbed is affected by temperature and humidity(moisture) of air and soil, and the maximum is not bigger than the maximum moisture absorption of sandy soil. The second is the process of water condensation determined by air vapor, soil surface temperature and the available energy of soil. The calculating values from Penman Monteith equation coincide with the measured data, which has proved the feasibility of applying the method to study water absorption and condensation in sandy soil.