Title
Surface Motion and Structural Instability Monitoring of Ming Dynasty City Walls by Two-Step Tomo-PSInSAR Approach in Nanjing City, China.
Abstract
Spaceborne Multi-Temporal Synthetic Aperture Radar (SAR) Interferometry (MT-InSAR) has been a valuable tool in mapping motion phenomena in different scenarios. Recently, the capabilities of MT-InSAR for risk monitoring and preventive analysis of heritage sites have increasingly been exploited. Considering the limitations of conventional MT-InSAR techniques, in this study a two-step Tomography-based Persistent Scatterers (PS) Interferometry (Tomo-PSInSAR) approach is proposed for monitoring ground deformation and structural instabilities over the Ancient City Walls (Ming Dynasty) in Nanjing city, China. For the purpose of this study we utilized 26 Stripmap acquisitions from TerraSAR-X and TanDEM-X missions, spanning from May 2013 to February 2015. As a first step, regional-scale surface deformation rates on single PSs were derived (ranging from 40 to +5 mm/year) and used for identifying deformation hotspots as well as for the investigation of a potential correlation between urbanization and the occurrence of surface subsidence. As a second step, structural instability parameters of ancient walls (linear motion rates, non-linear motions and material thermodynamics) were estimated by an extended four-dimensional Tomo-PSInSAR model. The model applies a two-tier network strategy; that is, the detection of most reliable single PSs in the first-tier Delaunay triangulation network followed by the detection of remaining single PSs and double PSs on the second-tier local star network referring to single SPs extracted in the first-tier network. Consequently, a preliminary phase calibration relevant to the Atmospheric Phase Screen (APS) is not needed. Motion heterogeneities in the spatial domain, either caused by thermal kinetics or displacement trends, were also considered. This study underlines the potential of the proposed Tomo-PSInSAR solution for the monitoring and conservation of cultural heritage sites. The proposed approach offers a quantitative indicator to local authorities and planners for assessing potential damages as well as for the design of remediation activities.
Year
DOI
Venue
2017
10.3390/rs9040371
REMOTE SENSING
Keywords
Field
DocType
Tomo-PSInSAR,two-tier network approach,structural instability monitoring,ancient wall,cultural heritage,Nanjing
Linear motion,Star network,Hotspot (geology),Synthetic aperture radar,Remote sensing,Groundwater-related subsidence,Interferometry,Ranging,Geology,Delaunay triangulation
Journal
Volume
Issue
ISSN
9
4
2072-4292
Citations 
PageRank 
References 
2
0.41
13
Authors
10
Name
Order
Citations
PageRank
Fulong Chen1126.51
Yuhua Wu2827.70
Yimeng Zhang333616.62
Parcharidis Issaak462.67
Peifeng Ma5122.36
Ruya Xiao620.41
Jia Xu7179.54
Wei Zhou831.46
Panpan Tang9205.74
Michael Foumelis1033.87