In the past 30 years,the small baseline subset(SBAS)InSAR time-series technique has emerged as an essential tool for measuring slow surface displacement and estimating geophysical parameters.Because of its ability to ...In the past 30 years,the small baseline subset(SBAS)InSAR time-series technique has emerged as an essential tool for measuring slow surface displacement and estimating geophysical parameters.Because of its ability to monitor large-scale deformation with millimeter accuracy,the SBAS method has been widely used in various geodetic fields,such as ground subsidence,landslides,and seismic activity.The obtained long-term time-series cumulative deformation is vital for studying the deformation mecha-nism.This article reviews the algorithms,applications,and challenges of the SBAS method.First,we recall the fundamental principle and analyze the shortcomings of the traditional SBAS algorithm,which provides a basic framework for the following improved time series methods.Second,we classify the current improved SBAS techniques from different perspectives:solving the ill-posed equation,increasing the density of high-coherence points,improving the accuracy of monitoring deformation and measuring the multi-dimensional deformation.Third,we summarize the application of the SBAS method in monitoring ground subsidence,permafrost degradation,glacier movement,volcanic activity,landslides,and seismic activity.Finally,we discuss the difficulties faced by the SBAS method and explore its future development direction.展开更多
Zhouqu County in Gansu Province, Northwest China, is typically highly prone to landslides. On July 12, 2018, a landslide blocked the Bailong River near Zhouqu County, posing a serious threat to the life and property o...Zhouqu County in Gansu Province, Northwest China, is typically highly prone to landslides. On July 12, 2018, a landslide blocked the Bailong River near Zhouqu County, posing a serious threat to the life and property of local residents and the safety of infrastructure. Small baseline subset interferometry synthetic aperture radar technology(SBAS-In SAR) was adopted to identify the potential active landslides in the surrounding area of Zhouqu County, using ascending and descending orbit Sentinel-1 satellite images taken from October 2017 to December 2018. The surface deformation areas detected by SBAS-In SAR were verified by optical remote sensing image interpretation and field investigation, and a total of 23 active landslides were identified finally. The deformation characteristics of four typical landslides are analysed in detail using deformation velocity and rainfall data. It is found that the deformation velocity of landslides in this area is mainly affected by rainfall and there is a lag effect. The results can provide a reference for the prevention and control of landslide risk in Zhouqu County.展开更多
The quantitative assessment of glacier flow velocity dynamics plays a pivotal role in understanding its response mechanisms concerning climate warming.This work provides a systematic quantitative assessment of the dec...The quantitative assessment of glacier flow velocity dynamics plays a pivotal role in understanding its response mechanisms concerning climate warming.This work provides a systematic quantitative assessment of the deceleration status of glaciers in this region by investigating the motion evolution of typical glaciers in Mount Gongga in recent years,thereby revealing the seasonal dynamics and inter-annual evolution over an extensive time span.We used the optical flow-small baseline subset(OF-SBAS)method to compute the time-series velocities of the Hai-luogou Glacier and the Mozigou Glacier using 178 archived Sentinel-1 satellite synthetic aperture radar(SAR)images from 2014 to 2021.The findings revealed a prominent seasonal pattern in glacier motion,characterised by cyclic variations in velocity from cold to warm seasons.Moreover,we identified variations in velocities across distinct regions of the glacier surface,underscored by the lag in the peak time node of glacier flow with increasing elevation.This pattern may have been determined by a combination of internal and external factors,including mass accumulation and ablation-driven subglacial drainage,as well as the glacier geomorphological setting.Furthermore,during 2015-2021,the glaciers on the eastern slope of Mount Gongga exhibited an overarching trend of deceleration.Notably,the ablation area of the Hailuogou Glacier recorded the most substantial deceleration,exceeding 8%per year.This study underscores the efficacy of the OF-SBAS method in extracting long-term glacier velocities.This work also establishes a robust foundation for the analysis of spatiotemporal fluctuations in glacier movement within the context of climate warming.展开更多
基金This work was funded by the National Key R&D Program of China(2019YFC1509205)the National Natural Science Foundation of China(Nos.42174023 and 41804015)+1 种基金the Postgraduate Scientific Research Innovation Project of Hunan Province(150110074)the Postgraduate Scientific Research Innovation Project of Central South University(212191010).
文摘In the past 30 years,the small baseline subset(SBAS)InSAR time-series technique has emerged as an essential tool for measuring slow surface displacement and estimating geophysical parameters.Because of its ability to monitor large-scale deformation with millimeter accuracy,the SBAS method has been widely used in various geodetic fields,such as ground subsidence,landslides,and seismic activity.The obtained long-term time-series cumulative deformation is vital for studying the deformation mecha-nism.This article reviews the algorithms,applications,and challenges of the SBAS method.First,we recall the fundamental principle and analyze the shortcomings of the traditional SBAS algorithm,which provides a basic framework for the following improved time series methods.Second,we classify the current improved SBAS techniques from different perspectives:solving the ill-posed equation,increasing the density of high-coherence points,improving the accuracy of monitoring deformation and measuring the multi-dimensional deformation.Third,we summarize the application of the SBAS method in monitoring ground subsidence,permafrost degradation,glacier movement,volcanic activity,landslides,and seismic activity.Finally,we discuss the difficulties faced by the SBAS method and explore its future development direction.
基金The work was financially supported by the National Key Research and Development Program of China(No.2018YFC1505402)the National Natural Science Foundation of China(Nos.41941019,41521002)+1 种基金the Key R&D project of the Science and Technology Department of the Sichuan Province of China(No.2019YFG0460)the Science and Technology Innovation Fund of the Sichuan Earthquake Agency(No.201901)。
文摘Zhouqu County in Gansu Province, Northwest China, is typically highly prone to landslides. On July 12, 2018, a landslide blocked the Bailong River near Zhouqu County, posing a serious threat to the life and property of local residents and the safety of infrastructure. Small baseline subset interferometry synthetic aperture radar technology(SBAS-In SAR) was adopted to identify the potential active landslides in the surrounding area of Zhouqu County, using ascending and descending orbit Sentinel-1 satellite images taken from October 2017 to December 2018. The surface deformation areas detected by SBAS-In SAR were verified by optical remote sensing image interpretation and field investigation, and a total of 23 active landslides were identified finally. The deformation characteristics of four typical landslides are analysed in detail using deformation velocity and rainfall data. It is found that the deformation velocity of landslides in this area is mainly affected by rainfall and there is a lag effect. The results can provide a reference for the prevention and control of landslide risk in Zhouqu County.
基金Othe Natural Science Foundation of China(42071084&U22A20565)Science and Technology Research Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(IMHE-CXTD-01&IMHE-CXTD-02)+1 种基金Science and Technology Plan Projects of Tibet Autonomous Region(XZ202301YD0002-03)the National Key RD Program of China(2023YFC3008300).
文摘The quantitative assessment of glacier flow velocity dynamics plays a pivotal role in understanding its response mechanisms concerning climate warming.This work provides a systematic quantitative assessment of the deceleration status of glaciers in this region by investigating the motion evolution of typical glaciers in Mount Gongga in recent years,thereby revealing the seasonal dynamics and inter-annual evolution over an extensive time span.We used the optical flow-small baseline subset(OF-SBAS)method to compute the time-series velocities of the Hai-luogou Glacier and the Mozigou Glacier using 178 archived Sentinel-1 satellite synthetic aperture radar(SAR)images from 2014 to 2021.The findings revealed a prominent seasonal pattern in glacier motion,characterised by cyclic variations in velocity from cold to warm seasons.Moreover,we identified variations in velocities across distinct regions of the glacier surface,underscored by the lag in the peak time node of glacier flow with increasing elevation.This pattern may have been determined by a combination of internal and external factors,including mass accumulation and ablation-driven subglacial drainage,as well as the glacier geomorphological setting.Furthermore,during 2015-2021,the glaciers on the eastern slope of Mount Gongga exhibited an overarching trend of deceleration.Notably,the ablation area of the Hailuogou Glacier recorded the most substantial deceleration,exceeding 8%per year.This study underscores the efficacy of the OF-SBAS method in extracting long-term glacier velocities.This work also establishes a robust foundation for the analysis of spatiotemporal fluctuations in glacier movement within the context of climate warming.
