Result evaluation of Coherent Target Model Product with long-term InSAR data set in Shanghai

Mingsheng Liao(1) , Yan Wang(1) , Deren Li(1) , and Lijun Lu(1)

(1) Wuhan University, P. O. Box C310, 129 Luoyu Road, 430079, Wuhan, China

Abstract

The coherent point target analysis provided an approach to exploit the temporal and spatial characteristics of interferometric signatures of long-term InSAR data stack to derive the surface deformation map. This method has initiated by A. Ferretti and F. Rocca etc. Now it’s philosophy has been developed in several application cases. If temporal decorrelation and atmospheric heterogeneities could be separated from the phase signal, the expanded technique of Differential-InSAR may improve the accuracy in deformation detection from centimeter to millimeter.

This presentation concentrates on the coherent point target analysis of long-term ERS-1/2 data set in Shanghai city, which has been affected by subsidence for more than eighty years. The local government has setup the benchmark network for monitoring the surface deformation in urban area using optical leveling. The CGPS network is also being constructed recently. The D-InSAR technology is also a potential tool for evaluating the urban subsidence since more measurement points may be found in lower costs.

Coherent targets are discrete point targets that exhibit phase stability over a long period of time. Using the methods of stacked differential interferograms, the phase series along time series due to atmospheric differences can be decreased through iterative procedures, and the deformation velocity can be measured in coherent targets. The data processing flow is constructed on a commercial software platform.

This research progress is prompted within the DRAGON Programme, a co-operational framework between China and ESA. The 22 scenes from the ERS-1/2 satellites covering the test area, shanghai between 1992 and 2000 were chosen and processed. The products based on the Coherent Point Target analysis are compared with ground leveling data. The construction of subsidence phenomena will be characterized by the InSAR result. Validation of deformation model obtained using InSAR technology with the one derived from ground leveling monitoring system is discussed.

 

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