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Li, T, Zhag, SY, Liu, JN, Long, SC, Jiang, TC, Xia, Y, Jiang, YX, Lu, X (2009). Fusing Multiple Remote Sensing Data to Monitor Tianjin Urban Subsidence. "CPGPS 2009: GLOBAL NAVIGATION SATELLITE SYSTEM: TECHNOLOGY INNOVATION AND APPLICATION, PROCEEDINGS", 268-273.

With the fast growing of China economy, many China cities over pumping groundwater and caused land subsidence. How to monitor the groundwater resource and pumping it reasonably needs to be taken into account. InSAR technology was used to monitor the land subsidence caused by water pumping in many cities and corresponding results can be seen in many papers. However, according, to the errors of decorrelation, atmosphere effect and orbit errors, the final subsidence results are not reliable for detecting the subsidence rate and range. Therefore, few cities have been established reliable InSAR processing system for monitoring city subsidence monthly or yearly. This paper accumulated 12 GPS continuous station data in Tianjin area and used it to derive the atmosphere effect overlapped with InSAR results. Meanwhile the GPS derived atmosphere screen had been put forward into InSAR results to be comparing and testing. The MODIS atmosphere results also have been fusing into InSAR results in Tianjin area for testifying. The primary results showed that MODIS data or not so reliable in most of the case for mitigate the atmosphere effect. This paper used GPS and MODIS data to mitigate the obvious the atmosphere errors and then compare the final subsidence map with the leveling data. The stacking method derived InSAR results showed that interferogram became more reasonable and reliable. It also showed that only in urban area with many buildings could we get the continuous fringes. Therefore, subsidence in these areas can be monitored by InSAR monthly or yearly. Fusing GPS, MODIS and leveling data made InSAR results more reasonable and more reliable.



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