Derivation of surface subsidence information in Bangkok (Thailand) by PS analysis of a limited number of interferograms

Jirathana Worawattanamateekul(1) , Jörn Hoffmann(2) , Richard Bamler(2) , Bert Kampes(2) , Nico Adam(2) , Achim Roth(2) , and Wladyslaw Altermann(3)

(1) RS-Tech Co., Ltd., 70/592 Moo 3 Krisadanakorn 19, 12120 Pathumthani, Thailand
(2) German Aerospace Center (DLR), Muenchnerstr. 20 Oberpfaffenhofen , 82234 Wessling, Germany
(3) Ludwig-Maximilians University of Munich, Luisenstr. 37, 80333 Munich, Germany


We used Permanent Scatterer (PS) interferometry to quantify surface subsidence in the Bangkok Metropolitan area with 20 ERS-1/2 acquisitions. Strong atmospheric influence and limited number of images are the main difficulties of this study. Despite these difficulties, our results have shown that we can obtain subsidence estimates with millimetric precision. By validation with independent leveling data, we show that the achievable precision at locations subsiding at approximately constant rates is better than pm 1.5 mm/y. The discrepancy between PS estimates and the reference leveling increases as the degree of temporal variability of subsidence rates increases. At 6 out of 10 investigated benchmarks the PS-derived subsidence rate estimates agreed better than pm 1.5 mm/y with the benchmark values. However, compared to benchmark leveling spatially varying subsidence field can be characterized much better from subsidence estimates from PS. The PS density of 28 PS/km^{2} makes our PS subsidence map the most detailed subsidence information of Bangkok to date.


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