- 期刊
利用衛星雷達影像分析臺灣西部水線變遷
Analysis Change Detection Waterline in West Taiwan Using Satellite SAR Imagery
摘要
本研究利用ERS-1與ERS-2衛星雷達進行台灣西部海岸水線萃取與變遷分析；由桃園觀音至屏東東港沿海地區長約400公里，觀測時間為1996年與2005年間隔10年共計23觀測航次。輔以光學衛星影像、水利署水深資料與中央氣象局潮位站潮位觀測資料，透過雷達影像進行萃取，獲取水陸交界之水線資料，經套疊水深地形資料並配合潮位資料與光學影像有效偵測出大範圍海岸長期變遷情形。本研究特別針對芳苑地區、海豐島洲、外傘頂洲進行深入分析，結果顯示在同一潮位下（約0.8 公尺）外傘頂洲面積由2005年縮小為1996年的1/3，東南端向東南漂移約700公尺，此外也發現2005年北港溪出海口沙洲與外傘頂洲逐漸往內陸靠近的趨勢；在同一潮位下約0.5公尺)海豐島洲地區1996年至2005年之間面積變化情形不大，但沙洲南移約1.5公里，其沙洲亦有向內陸靠近的趨勢。總結本研究成果可以發現，利用長期密集雷達影像觀測與水線萃取，配合潮位資料，可以有效獲取潮間帶水深的地形概況與瞭解水線位移或沙洲面積變化情形。
並列摘要
This study applied satellite SAR images from ERS-1 and ERS-2 for water line extraction and change detection along the west costal area, covering from Kuan-in, Taoyuan to Tung-Kang, Pintung a total of about 400 km long. The images were acquired in the years of 1996 and 2005 with 10 years time span with 23 image tracks (total 92 image sets of 100 km by 100 km) In particular, the environmental sensitive areas of Fang-Yuan, Hai-Feng-Dao Chou, and Wai-San-Ting Chou, were chosen for detailed analysis. In addition to SAR images, we also incorporated optical satellite images, water depth map from Water Resource Bureau, and tidal records from tidal stations operated by Central Weather Bureau. This is important to ensure all the water line can be calibrated to the same tidal level. From the results, it is found that Wai-San-Ting Chou moved southward about 700 meters during 10 years period and it was shrunk to just one-third of its size in 1996. It is also found that the surroundings costal waters of Wai-San-Ting Chou and estuary of Pei-Kang River moved inward to west costal. The water channel was becoming more deposited as a result. Finally, Hai-Feng-Dao Chou itself moved southward about 1.5 km although its size remained quite the same during 1996 and 2005, and it also presented a clear tendency of inward moving. From the results we reported here, it is concluded that satellite remote sensing by SAR, aided by ground tidal data, bathematric map, and optical images, provides an effective and efficient tool for costal water changes in terms of large area coverage and long time span.