| 引用本文: | 毛 俊,伍靖伟,刘雅文,等.盐分对季节性冻融土壤蒸发影响的试验及数值模拟研究[J].灌溉排水学报,0,():-. |
| Mao Jun,Wu Jingwei,Liu Yawen,et al.盐分对季节性冻融土壤蒸发影响的试验及数值模拟研究[J].灌溉排水学报,0,():-. |
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| 盐分对季节性冻融土壤蒸发影响的试验及数值模拟研究 |
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毛 俊1, 伍靖伟1, 刘雅文1, 吴谋松2
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1.武汉大学 水资源与水电工程科学国家重点实验室;2.南京大学 国际地球系统科学研究所
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| 摘要: |
| 摘要：【目的】探究盐分对季节性冻融土壤蒸发的影响规律。【方法】在内蒙古河套灌区开展了B1和B2两组不同含盐量下（B1：7.80 g/kg；B2：41.16 g/kg）的野外土柱蒸发试验，建立了考虑盐分影响（该影响由盐分阻抗和土壤表面阻抗体现）的冻融土壤蒸发数值模拟模型。采用土柱试验结果对模型进行了率定验证，并与SHAW模型进行了对比分析。在此基础上，应用该模型对9种不同含盐量（S1～S9：0、2.5、5、7.5、10、15、20、35、50 g/kg）下的冻融土壤蒸发进行了模拟。【结果】土壤含盐量不同导致的土壤蒸发强度差异显著，特别是在土壤冻结初期和融通期，土壤含盐量较低的B1土柱蒸发强度分别约是B2土柱的1.5倍和1.8倍；与SHAW模型相比，考虑盐分影响的冻融土壤蒸发模型能准确反映受盐分影响的冻融土壤蒸发过程，更适用于受盐渍化影响的季节性冻土区；冻融土壤蒸发量随含盐量增加呈现出先增后减的变化趋势，在含盐量为S6时，土壤蒸发量最大，为136.3 mm；相比无盐土S1，S2～S6的土壤蒸发分别增加了1.09%、13.68%、56.22%、73.73%以及86.46%，而对比S6，S7～S9的土壤蒸发分别减少了10.20%、26.34%和42.55%。【结论】盐分对季节性冻融土壤蒸发影响显著，其作用为先促进后抑制，考虑盐分影响的冻融土壤蒸发模型可以提升盐渍农田蒸发的模拟精度。 |
| 关键词: 盐分;冻融土壤;土壤蒸发;数值模拟 |
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| 分类号:S125.7 |
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| Experimental and numerical simulation study on the salt effects on the evaporation from freezing/thawing soil |
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Mao Jun1, Wu Jingwei1, Liu Yawen1, Wu Mousong2
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1.State Key Laboratory of Water Resource and Hydropower Engineering Science, Wuhan University;2.International Institute for Earth System Science
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| Abstract: |
| Abstract: 【Background】Seasonal frozen soil is widely distributed in our country as an important land resource. With the growth of population, it’s necessary to develop and utilize the seasonal frozen soil. Hetao Irrigation District is one of the three major irrigation areas and a typical seasonal frozen area, which is located in an arid and semi-arid region in Inner Mongolia, China. However, it is often threatened by soil salinization and water shortage, which are the main factors that constrain the sustainable development of agriculture in China. Soil evaporation as a significant part of surface energy and water balance in seasonal frozen regions, it plays an important role in water management and formulation. In order to control soil salinization and save water resource, it is of great significance to calculate soil evaporation from freezing/thawing soil accurately. However, soil evaporation is affected by salt content. Therefore, it’s necessary to calculate soil evaporation considering salt effects.【Objective】The purpose of this paper is to evaluate the impacts to evaporation from freezing/thawing soil with different salt contents.【Method】The soil columns with different salt contents of B1 and B2（B1：7.80 g/kg；B2：41.16 g/kg） experiments were conducted in Inner Mongolia, China, and its process of soil evaporation with various salt contents was observed and analyzed during different freezing/thawing period. Based on that, a numerical evaporation model considering the salt effects reflected by salt impedance and soil surface impedance was developed, and it was calibrated/validated by the experimental observations and compared with SHAW model. Then, the numerical model was used to simulate the evaporation processes from freezing/thawing soil under 9 various salt contents（S1-S9：0, 2.5, 5, 7.5, 10, 15, 20, 35, 50 g/kg）.【Result】The difference in evaporation rate with various salt contents is notable, especially in the beginning freezing period and thawed period, the average evaporation rate of B1 soil column with low salt content is 1.5 times and 1.8 times of that of B2 soil column, respectively. Compared with SHAW model, the established numerical model in this study is able to simulate evaporation process reasonably well and more suitable for seasonal frozen soil affected by salinization. The evaporation from freezing/thawing soil increases first and then decreases with the increase of salt content, and when the salt content is S6（15 g/kg）, the soil evaporation is the largest reaching 136.3 mm; Compared with S1 of salt free, soil evaporation of S2-S6 increase by 1.09%、13.68%、56.22%、73.73% and 86.46%, respectively, while compared with S6, that of S7-S9 decrease by 10.20%、26.34% and 42.55%, respectively.【Conclusion】Salt has a great significant impact on the evaporation of seasonal freezing/thawing soil, and its effect is to promote evaporation first and the inhibit. The established numerical evaporation model considering salt effects can improve the accuracy of evaporation from saline farmland. This study helps to understand the mechanism of soil evaporation under salt effects in seasonal freezing regions and provide a useful tool for simulating soil and water movement in such region. |
| Key words: Salt; Freezing-thawing soil; Evaporation rate; Numerical simulation. |
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