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Chen K.-S.,National Central University | Wang H.-W.,National Central University | Wang C.-T.,National Central University | Chang W.-Y.,National Science Council
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2011

In this paper, coastal line changes were monitored and analyzed from a sequence of ERS-1/2 SAR images covering the years 1996 to 2005, totaling 44 images for each year. Waterlines were extracted using a multi-scale edge detection algorithm, and further refined by means of morphology. Substantial analysis was carried out in conjunction with ground survey and sonar bathymetric mapping. In addition, tidal records were used to ensure all the shore lines been calibrated to the same tidal level. Results showed that Waisanting Sandbar, a north-southward sandbar, experienced significant accretion and erosion, moving southward about 700 meters during a 10-year period, and shrinking to just one third of its 1996 size. The surrounding coastal waters and the estuary of the Peikang River receded substantially, moving inward toward the coastal flat. The water channel became even more heavily deposited as a result. Finally, Haifengdao Sandbar, another sandbar, moved southward about 1.5 km, although its size remained the same from 1996 to 2005. It also showed a clear tendency to receding inward. We conclude that satellite remote sensing by SAR, aided by ground tidal data, bathymetric maps, and optical images, provides an effective and efficient tool for understanding coastal processes over large areas of coverage and long time spans. © 2008 IEEE. Source

Chang C.-H.,Central Weather Bureau | Lin T.-L.,National Taiwan University | Wu Y.-M.,National Taiwan University | Chang W.-Y.,National Science Council
Bulletin of the Seismological Society of America | Year: 2010

We have collected a large number of accelerograms recorded by the Taiwan Strong Motion Instrumentation Program (TSMIP) stations to study the thickness variations of Quaternary alluviums beneath Lan-Yang Plain, Taiwan, using an Sp converted wave. The estimated thicknesses of the Quaternary sediments inferred by the travel-time difference of S and Sp waves are between 200 and 1400 m and become thicker toward the northeast. In general, our resulting features of the time difference of arrivals between Sp and S waves are consistent with the previous studies on thickness variations of the Quaternary alluviums beneath Lan-Yang Plain assuming the converting point is at the unconsolidated Quaternary alluvial sediments-Miocene basement interface. Our study suggests that this technique of using P-S converted phases could be applied to the other populated basins or plains in the Taiwan region based on its dense coverage of the TSMIP stations and high seismic activity. This technique is simple and time effective and can be used to determine the general characteristics of velocity/thickness structure of a study area. Source

Chen K.-S.,National Central University | Wu A.-M.,National Space Organization | Chern J.-S.,China Institute of Technology | Chen L.-C.,National Central University | Chang W.-Y.,National Science Council
Proceedings of the IEEE | Year: 2010

This paper presents an overview of the current status and data applications of FORMOSAT-2, Taiwanese's first earth observation satellite mission. Highlights of its contributions to monitoring of global natural disasters and earth environmental changes will be illustrated. The FORMOSAT-2 satellite successfully complements existing high spatial resolution imaging satellites such as SPOT-5, IKONOS, and QuickBird, among others, with its unique capability of daily revisits worldwide. The FORMOSAT-2 follow-up program to ensure data continuity to the user community is briefly introduced. © 2006 IEEE. Source

Wen S.,National Chung Cheng University | Hsu H.-J.,National Chung Cheng University | Chang W.-Y.,National Science Council | Chang W.-Y.,National Dong Hwa University | Chen C.-H.,National Chung Cheng University
Tectonophysics | Year: 2012

A moderate earthquake occurred near the town of Jiasian in Kaohsiung County, Taiwan, at 8:18. AM (local time) on 4 March 2010. The epicenter was located about 60. km northeast of Kaohsiung City. About 70 aftershocks occurred during the same day. In this study, we invert a 3-D velocity structure beneath the southwestern part of Taiwan. Furthermore, we accurately determine the locations, the focal mechanisms, and the regional stress tensor from the inverted 3-D velocity model. According to the results, we can conclude: (1) a low Vp anomaly zone with a high Vp/Vs ratio in the southwestern part of the research area may have been caused by the subducting oceanic lithosphere; (2) a high Vp anomaly zone with low Vp/Vs ratio in the northeastern part of the research area demonstrates that there is an intervening continental sliver; (3) based upon the inverted 3-D velocity model and the relocated seismicity, we suppose that there might be a NW-SE trending blind fault which dips to the north; (4) according to the results of the focal mechanisms of the Jiasian earthquake sequence and the regional stress tensor inversion, we can surmise that the possible blind fault may be a thrust fault with left-lateral characteristic; and, (5) based upon the different tectonic process in this area, we can conclude that the Chishan Transfer Fault Zone leads to a possible oblique slip fault locks and exhibit high seismic potential which caused the Jiasian earthquake sequence. © 2012 Elsevier B.V. Source

Huang W.-L.,National Chiayi University | Lee C.-H.,National Science Council | Chen Y.-R.,National Chiayi University
Plant Cell, Tissue and Organ Culture | Year: 2012

Osmotic stress and endogenous hormone levels may have a role in shoot organogenesis, but a systematic study has not yet to investigate the links. We evaluated the changes of the endogenous indole-3-acetic acid (IAA) and abscisic acid (ABA) levels in rice (Oryza sativa L. cv. Tainan 5) callus during shoot organogenesis induced by exogenous plant growth regulator treatments or under osmotic stress. Non-regenerable callus showed low levels of endogenous ABA and IAA, with no fluctuation in level during the period evaluated. The addition of 100 μM ABA or 2 mM anthranilic acid (IAA precursor) into Murashige and Skoog basal induction medium containing 10 μM 2,4-D enhanced the regeneration frequency slightly, to 5 and 35%, respectively, and their total cellular ABA or IAA levels were increased significantly, correspondingly to the treatments. However, the regeneration frequency was greatly increased to 80% after treatment with 0.6 M sorbitol or 100 μM ABA and 2 mM anthranilic acid combined. Both treatments produced high levels of total cellular ABA and IAA at the callus stage, which was quickly decreased on the first day after transfer to regeneration medium. Thus, osmotic stress-induced simultaneous accumulation of endogenous ABA and IAA is involved in shoot regeneration in rice callus. © 2011 Springer Science+Business Media B.V. Source

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