Solid earth deformation monitoring using satellite altimetry in southwestern coasts in Taiwan

A novel method of using waveform retracked altimeter observations on land for the monitoring of the solid Earth deformation in Taiwan is described in the article. The southwestern coasts of Taiwan have been experiencing a significant land subsidence in the rate of ~8 em/year, due to, in part, the excess extraction of the underground water. The first-order leveling networks and the GPS control points available in the area were used to verified the results of the waveform retracked altimeter observation. In this study, we proposed to use TOPEX/Poseidon (TiP) altimeter land observations from 1992--2002 on one TIP groundtrack that passes the southwestern coasts of Taiwan where is part of the Chia-Nan Plain with the main vegetation being rice paddy. This special vegetation and flat terrain provide an opportunity for successful waveform retracking. The comparison between TiP retracked result and that from the leveling network and GPS control points are presented.