Shenzhen Surface Deformation Monitoring Research Based On PS-DIn SAR Technology

Urban Land Subsidence is a vertical surface deformation phenomena formed from natural factors and human factors. Serious land subsidence would become a geological disaster. In China, there are more than 90 cities and regions have land subsidence in different degrees, causing economic losses over hundred billion Yuan. Land subsidence has been one of the major geological disasters to constrain regional environmental and social economic sustainable development.Developed in recent years, Permanen Scatterers DInSAR(PS-DInSAR) is a new microwave remote sensing technology to monitor the surface deformation in long periods, which uses permanent scatterers points with stable status in long sequence SAR images to analyze phase change in time series, and extract surface deformation information. Comparing to conventional land subsidence monitoring techniques (precise leveling, GPS measurements, etc.), besides the same advantage such as large area, low cost, quick and accurate, PS-DInSAR has some features including all-time, all-weather, large-scale, high-precision belonged to synthetic aperture radar measurement technology, also can effectively overcome the issues in conventional DInSAR technology including spatial decorrelation,temporal decorrelation and atmospheric delay impaction in monitoring long periods surface deformation.Therefore, this thesis use Shenzhen area as research object to explain how to use PS-DInSAR technology and 20 ENVISAT ASAR data for PS-DInSAR processing, The process use StaMPS algorithm and the combination of discrete features and the relevant characteristic in interference phase to identify and extract the point of permanent scatterers (PS point), then calculate the weight of interference phase through the time series sequence of PS points, ultimately get land subsidence monitoring information in Shenzhen area and show the results in the direction (LOS) deformation rate-9.3mm/a～7.5mm/a of satellite sight line. The result means that Shenzhen's land subsidence prevention and treatment should be executed without delay. Based on the Shenzhen land subsidence information acquired by PS-DInSAR, this thesis analyzes the main deformation zone in Shenzhen. The analysis shows Shenzhen coastal areas have ground subsidence in vary degrees, especially in Bao'an District. The thesis preliminary analyzes the reason of surface deformation, including land reclamation, underground construction, urban construction and groundwater exploit. Land reclamation is the main reason of land subsidence in Bao'an District, the city surface construction, subway construction and other large-scale exploitation of groundwater municipal building are main reasons of land subsidence in city and subway line.The research result represents some theoretical and practical significance of Shenzhen land subsidence disaster prevention and mitigation. At the end, this thesis gets a summary of the study, points out the shortcomings of the research process and possible future works, indicate the research content and emphasis at the next stage.