考虑空气影响的干旱区土壤水分运移模式研究

在前人研究的基础上,根据石河子垦区的实际情况,确定模型特定的边界条件及参数,建立适合该区的包气带-饱和带水、气二相流的质热传输模型,模拟土壤水分、温度的动态变化,并利用实测土壤温度、土壤含水率数据进行模型检验。结果表明:模拟的土壤温度和含水率能够较好地反映实测值的变化规律,各土层模拟精度评价指标表明考虑空气影响的模拟结果更接近实测结果。对于9.7 mm日降水量的入渗深度,耦合模型可影响20 cm深土壤含水率,单相模型可影响到30 cm深左右。降水当日考虑空气模拟的蒸发速率比不考虑空气模拟的蒸发速率大7.7%;降水后1 d,不考虑空气影响导致蒸发速率比考虑空气的小3.19%。计算模拟期2种模型土壤总蒸发量,相差不大。根据2种模型水量平衡分析结果对比蒸发量的计算值与模拟值,发现考虑空气影响的模型模拟结果更可靠。

Transport Mode of Soil Moisture in Arid Areas Considering Air Effect

In order to accurately describe the transport mode of soil moisture in arid areas, based on previous studies, the model parameters and specific boundary conditions were determined according to the actual situation of Shihezi Reclamation, and a two-phase mass and heat flow transfer model including water and air was established fit for this vadose zone-saturated zone, thereby simulating the dynamic changes of soil moisture, soil temperature. The measured soil temperature, soil moisture were used to test models. The results showed that the simulated soil temperature and moisture could well reflect variation of measured values. Accuracy assessment indicators showed that the simulation accuracy of each soil layers was high. Simulated results of the model considering the impact of air were closer to the measured results. For the day rainfall of 9.7mm, infiltration depth could affect soil moisture of about 20cm depth for coupling model, and up to about 30cm depth for a single model. The average evaporation rate of the model considering air in the rain day was 7.7% more than the result of the model without considering air. In the day right after the rainfall event, the results without considering the effect of air pressure caused evaporation rate 3.19% lower than the results considering air effect. Calculating the total evaporation during the simulation period, the results of the two models were very close. But based on the results of water balance analysis of the two models, comparing calculated evaporation and simulated evaporation, the results of the model considering air influence were considered reliable.