ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    多年冻土InSAR地表变形监测与土壤水热过程研究

    Research on InSAR Surface Deformation and Soil Hydrothermal Process in Permafrost

    • 摘要: 地表变形是反映活动层冻融过程的重要特征。为研究地表变形与活动层水热过程的相关性,采用SBAS-InSAR技术对祁连山地区野牛沟多年冻土区近5a的地表变形进行长期连续监测,并基于野外观测数据研究了地表变形与土壤水热过程的关系。结果表明,冻融过程与水力侵蚀作用引起的地表变形最为显著,地表变形表现出明显的季节性特征。冻融过程引起的地表累积变形较小,年际冻胀、融沉幅度约为10~20 mm;水力侵蚀引起的地表累积变形较大,年际地表变形幅度超过50 mm。野外观测数据表明活动层土壤温度具有轻微的下降趋势,负温等温线下探深度增加、历时加长,冻结锋面交汇日逐渐提前。地表变形与土壤温度、土壤湿度具有较好的相关性,在土壤水分富集区相关性更强,相关系数分别为−0.522、−0.415(P<0.001)。土壤水分富集区土壤含水量的变化对地表冻胀、融沉幅度变化的影响也更显著,两者具有良好的线性关系。笔者定量描述了活动层地表变形与土壤水热过程的关系,对大范围活动层冻融参数的监测研究具有参考意义。

       

      Abstract: Surface deformation is an important feature reflecting the freeze-thaw process of active layer. To study the correlation between surface deformation and active layer hydrothermal processes, SBAS-InSAR technique was used to continuously monitor the surface deformation in the permafrost area of Yeniugou in Qilian Mountains in recent 5a, and the relationship between surface deformation and soil hydrothermal process was studied based on field observation data. The results indicate that the surface deformation caused by freeze-thaw process and hydraulic erosion is the most significant, and the surface deformation exhibits obvious seasonal characteristics. The cumulative surface deformation caused by freeze-thaw process is relatively small, and the interannual amplitude of frost heave and melt subsidence is about 10~20 mm; The cumulative surface deformation caused by hydraulic erosion is relatively large, with an interannual surface deformation exceeding 50 mm. Field observation data shows a slight downward trend in soil temperature in the active layer, with an increase in depth and duration of the negative temperature isotherm, and a gradual advance in the freezing front intersection date. The surface deformation has a good correlation with soil temperature and soil moisture, in areas where soil moisture enriched, the correlation is stronger, with correlation coefficients of −0.522 and −0.415 (P<0.001), respectively. The changes in soil moisture content in soil moisture rich areas also have a more significant impact on the amplitude of surface frost heave and thaw settlement, and there is a good linear relationship. This article quantitatively describes the relationship between surface deformation of active layers and soil hydrothermal processes, which has reference significance for monitoring and studying the freeze-thaw parameters of large-scale active layers.

       

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