:: Volume 2, Issue 2 (9-2014) ::
jgit 2014, 2(2): 61-73 Back to browse issues page
An Enhanced Algorithm based on Radar Interferometry for Monitoring Land Subsidence Caused by Over-Exploitation of Groundwater
Maryam Dehghani *
Shiraz University
Abstract:   (5138 Views)
Over-exploitation of groundwater has caused land subsidence in large rural areas located in Mashhad sub-basin, northeast of Iran. Time series analysis using Interferometric SAR (InSAR) data has shown its ability to monitor the temporal evolution of land subsidence. In this paper, time series analysis based on Small Baseline Subset (SBAS) algorithm is applied to study the Mashhad sub-basin subsidence. 18 interferograms were generated using 12 ENVISAT ASAR images spanning between 2003 and 2005. In order to decrease the temporal decorrelation effect caused by the agricultural fields, only interferograms with small temporal baselines are used in the time series analysis. However, to prevent the solution from the rank deficiency, it is tried to generate as many interferograms as possible. Because the interferograms with large spatial baselines are influenced by the topographic artifacts, they are refined before using in the time series analysis. Moreover, the atmospheric-error free deformation corresponding to every acquisition time is retrieved by applying the smoothing constraint into the least squares solution. The maximum deformation rate in the study area is estimated as ~23 cm/yr. The compressibility of the aquifer system is finally investigated by the quantitative integration of the InSAR displacement measurements with observations of the hydraulic head fluctuations at few piezometric wells.
Keywords: Radar Interferometry, Time Series Analysis, Subsidence
Full-Text [PDF 1528 kb]   (2135 Downloads)    
Type of Study: Research |
Received: 2015/09/8 | Accepted: 2015/09/8 | Published: 2015/09/8



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Volume 2, Issue 2 (9-2014) Back to browse issues page