黄土台塬滑坡变形的时序InSAR监测分析

Monitoring Slope Displacements of Loess Terrace Using Time Series InSAR Analysis Technique

黄土台塬由于经常性的农业灌溉容易造成边缘区域滑坡发育。因此,需要利用有效手段对这些潜在的滑坡隐患进行早期识别与监测。利用时间序列合成孔径雷达干涉测量(interferometric synthetic aperture radar, InSAR)技术对2016-01至2018-08期间获取的升降轨Sentinel-1数据集进行分析,获取了甘肃永靖黑方台典型台塬地区的滑坡隐患分布情况。将InSAR结果与GPS观测资料进行对比,验证了时序InSAR处理方法的有效性。对该地区滑坡的历史变形分析表明,持续的农业灌溉引起的地下水位抬升是台塬边缘坡体失稳的主要诱因。同时,InSAR时序分析发现,研究区域内的跨黄河大桥受季节更替和温度波动的影响,存在周期性变形现象。实验结果证明了时序InSAR方法在地表变形监测中的有效性,可在黄土滑坡识别与监测防治中发挥重要作用。

Persistent agricultural irrigation makes loess terrace prone to landslide hazards.Therefore,it is necessary to identify and monitor the potential landslides with effective ways.In this paper,the time series interferometric synthetic aperture radar(InSAR)analysis technique is utilized to analyze both descending and ascending Sentinel-1 data stacks covering the period from January 2016 to August 2018.Active slopes on the Heifangtai terrace and surrounding area in northwest China are identified.Comparison between time series InSAR measurements and GPS measurements is carried out.Time series displacement analysis reveals that agricultural irrigation poses a great threat to the stability of slopes at the terrace edge.Meanwhile,temperature variation related displacements are also identified on bridges across the Yellow River with high correlation.Our study confirms the effectiveness of time series InSAR method,which can play a significant role in the identification and prevention of loess landslides.