郑策, 高万德, 陈云飞, 卢玉东, 刘秀花. 毛乌素沙地冻融期气态水迁移机理及影响因素[J]. 水科学进展, 2022, 33(2): 227-239. DOI: 10.14042/j.cnki.32.1309.2022.02.007
引用本文: 郑策, 高万德, 陈云飞, 卢玉东, 刘秀花. 毛乌素沙地冻融期气态水迁移机理及影响因素[J]. 水科学进展, 2022, 33(2): 227-239. DOI: 10.14042/j.cnki.32.1309.2022.02.007
ZHENG Ce, GAO Wande, CHEN Yunfei, LU Yudong, LIU Xiuhua. Vapor transfer mechanism and its influence factors during the freeze-thaw periods in Mu Us Sandy Land[J]. Advances in Water Science, 2022, 33(2): 227-239. DOI: 10.14042/j.cnki.32.1309.2022.02.007
Citation: ZHENG Ce, GAO Wande, CHEN Yunfei, LU Yudong, LIU Xiuhua. Vapor transfer mechanism and its influence factors during the freeze-thaw periods in Mu Us Sandy Land[J]. Advances in Water Science, 2022, 33(2): 227-239. DOI: 10.14042/j.cnki.32.1309.2022.02.007

毛乌素沙地冻融期气态水迁移机理及影响因素

Vapor transfer mechanism and its influence factors during the freeze-thaw periods in Mu Us Sandy Land

  • 摘要: 受冰-水间相变影响, 冻融期内土壤水、热传输过程变得复杂, 研究气态水分布特征与运移规律, 可为厘清冻融过程中沙地包气带水文循环机理提供关键信息。通过在毛乌素沙地建立原位监测点, 并利用修改后的Hydrus-1D冻融程序建立包气带水-汽-冰-热耦合数值模型, 对冻融期包气带气态水迁移过程展开研究。结果表明: 模拟与实测土壤水分及温度变化拟合较好, 证实所建立的模型具有良好的精度以及适用性; 对比典型未冻结、初始冻结、向下冻结以及融化时段结果可知, 冻融过程会改变剖面土壤水分、含冰量以及水汽密度分布, 其中水汽密度变化与温度联系紧密; 冻结后, 由温度梯度驱动的非等温气态水通量在总水分通量中的占比超过90%, 表明气态水占据主导地位, 其运移过程对于剖面土壤水分分布以及高含水量带出现有重要影响。

     

    Abstract: Due to the phase transition between ice and water, soil water and heat transport show complexity during freeze-thaw periods. To investigate the distribution and transfer characteristics of water vapor can provide key information for better understanding the mechanisms of the hydrological cycle in the vadose zone of the sandy land. By establishing the in-situ observation site in the Mu Us Sandy Land, as well as building a coupled water, vapor, ice, and heat model through the modified software program, an analysis was conducted for the vapor transfer process during the freeze-thaw cycles. Results showed that the simulated water content and temperature are highly consistent with the measured data, suggesting a good accuracy and applicability of the proposed model. By comparing the simulation results of the selected non-freezing, initial freezing, downward freezing, and thawing periods, it can be found out that the distribution of soil water content, ice content, and vapor density in the profile changed, and the variation in vapor density was closely related to soil temperature. When soil was frozen, the thermal vapor flux driven by temperature gradient accounted for more than 90% of the total soil water fluxes, and vapor transfer played a critical role in affecting the soil moisture distribution of the profile.

     

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