季节性冻土的水热作用机制研究——以古尔班通古特沙漠南缘为例

【目的】阐明新疆干旱区冻融土壤的水热耦合关系,建立在冻结融化过程中土壤水热耦合模型。【方法】以土壤水动力学、冻土物理学和统计学为理论基础,利用土壤水分与温度测量系统对不同土层深度土壤的温度和湿度进行测量,比较土壤含水率和温度随时间与深度的变化情况,研究了新疆典型干旱区细土平原区与沙漠交错带的冻融土壤水热迁移规律,分析不同土层深度土壤在冻结期、融化期的水热变化特征。【结果】土壤冻结融化过程中,各层土壤的液态含水率、温度均与环境温度的变化趋势基本一致,但随着土层深度增加,土壤温度和含水率的变化趋势均在逐渐减弱;深层土壤的液态含水率在冻结融化过程中基本不随环境温度升降发生变化,浅层5、20 cm土层的温度和含水率之间具有耦合效应。【结论】季节性冻土的水分和温度之间具有耦合效应。

Study on the Hydrothermal Mechanism of Seasonal Frozen Soil:A Case Study about the Southern Margin of the Gurbantunggut Desert

【Objective】We aim at illustrating the coupling relationship between water and heat in freezing-thawing soil in arid region of Xinjiang, so as to establish a soil hydrothermal coupling model in the process of freezing and thawing.【Method】Based on soil hydrodynamics, frozen soil physics, and statistics, soil temperature and humidity in different depths were measured by measurement system, and the changes of soil temperature and moisture along with time and depth were compared. The law of water and heat transfer in freezing-thawing soil of the ecotone between fine soil plain area and desert in typical arid region of Xinjiang was studied, in addition, the water and heat change characteristics of soils during freezing and thawing period were analyzed.【Result】The variation trends of soil moisture and soil temperature in each layer were basically consistent with the changing trend of environmental temperature in the process of freezing and thawing. However, the variation trend of soil temperature and soil moisture gradually weakened with the increase of soil depth. The soil moisture of deep layers did not change with the increase or decrease of ambient temperature during the freezing-thawing process, while there was a coupling effect between soil temperature and soil moisture in shallow layers(5 cm and 20 cm)of soil.【Conclusion】There was a coupling effect between temperature and moisture of seasonal frozen soil.