稳定积雪覆盖下的季节性冻土水分特征及其数值模拟

Characteristics and Numerical Simulation of Moisture in Seasonal Frozen Soil under the Stable Snow Cover

为了深入研究积雪覆盖边界条件下的土壤水分迁移规律,通过冬季野外土壤水分观测试验,利用土壤水动力学理论,建立了稳定积雪覆盖条件下季节性冻土水分迁移模型。研究结果表明,积雪覆盖土壤比裸地平均地温高出1℃,土壤体积含水率(土壤剖面0～100cm内)高出2%,体现了积雪覆盖不仅能够阻碍土壤热量散失,而且能保持土壤墒情;建立的水分迁移模型能够精准的模拟积雪覆盖条件下冻结土壤水分迁移动态,其相对平均误差仅为3.51%。研究结果对于丰富和完善冻土水分迁移理论,解决春旱和冬小麦"冷拔"等问题具有重要的理论和实践意义。

For an in-depth study on the movement characteristics of soil moisture under the snow-covered boundary conditions, a moisture transfer model of the seasonal frozen soil under the stable snow-covered conditions was established based on the field measurements of soil moisture in the winter and the soil hydrodynamics theory. The results showed that the average tempera- ture of soil covered with snow is 1℃ higher than the bare soil and the water content of unit volume （between 0 and 100 cm of the soil profile） is 2% higher,which suggested that the snow cover can not only prevent the loss of soil heat but also maintain the soil moisture content. The model can simulate accurately the transfer dynamics of frozen soil under the snow cover,and the relative average error is only 3.51%. The research results have important theoretical and practical significances to improve the moisture transfer theory of frozen soil and to solve the spring drought and ＂cold drawing＂ of winter wheat problems.