TOPS和ScanSAR模式InSAR在广域地灾隐患识别中的联合应用

Combining Application of TOPS and ScanSAR InSAR in Large-Scale Geohazards Identification

  • 摘要: 星载合成孔径雷达干涉测量技术(interferometric synthetic aperture radar,InSAR)能够探测地表微小形变信息,但目前开展广域尺度下InSAR地灾隐患识别在技术层面仍存在很大的挑战性:如何“广域、快速、经济”地获取可靠的InSAR产品仍是地灾隐患识别“普查”的重点。哨兵1号(Sentinel-1)渐进逐行扫描模式(terrain observation with progressive scans,TOPS)和先进陆地观测卫星(advanced land observing satellite, ALOS)-2合成孔径雷达扫描模式(scanning synthetic aperture radar,ScanSAR)具有超大幅宽对地成像能力,因此,综合利用距离向频谱分割(range split spectrum)、Stacking-InSAR等技术,在金沙江中下游四川省攀枝花市至乌东德水电站河段,基于宽幅成像合成孔径雷达(synthetic aperture radar, SAR)数据开展多时相InSAR联合识别地灾隐患的应用,野外查证发现TOPS和ScanSAR模式InSAR数据识别的地灾隐患位置在实地几乎都存在形变迹象。

     

    Abstract:
      Objectives  InSAR technique has the ability to detect small deformation of the earth's surface. However, it is still a great challenge to identify the potential geohazards using InSAR in wide area. How to obtain reliable InSAR products in "large-scale, fast and economic" is still the key work of general survey for geohazards identification.
      Methods  Sentinel-1 TOPS and ALOS-2 ScanSAR data have large-wide swaths of hundreds of kilometers. Therefore, range split spectrum, Stacking-InSAR and other technologies are comprehensively used to identify geohazards using Sentinel-1 TOPS and ALOS-2 ScanSAR data in the Jinsha River area from Panzhihua City to Wudongde hydropower station. Firstly, sub-swath images of ScanSAR are processed with each other by differential interferometry, and range split spectrum method is used to estimate and compensate ionospheric delay for SAR interferometry.Then, TOPS full swath ima- ges are processed with perpendicular and temporal baselines of less than 200 m and 60 d, respectively. Finally, linear deformation rates of TOPS and ScanSAR data are estimated using Stacking-InSAR technique.
      Results  Forty-six potential geohazards are identified using Sentinel-1 TOPS data (January 2018 to January 2019), and ALOS-2 ScanSAR data (February 2017 to February 2020) have identified forty-four potential geohazards. Field investigations show that there are almost deformation phenomena in the location of identified geohazards by InSAR.
      Conclusions  The combined applications of TOPS and ScanSAR modes can fully grasp the situation of geological hazards as far as possible.

     

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