卫星影像分析近岸波场之探讨-近海水文中心-成功大学.PDF

第 屆海洋工程研討會論文集國立中山大學民國 89 年11 月 Proceedingsofthe nd Ocean EngineeringConferencein Taiwan ，RepublicofChina Nationa1Sun Yat-senUniversity November ，2000 衛星影像分析近岸波場之探討 林鴻朋鳥 l 董束璟 莊士賢 3 高家俊 4 摘要 衛星遙測具有廣域涵蓋的特性，為從事海洋波浪觀測之重要工具之 -0 本文探討應用 SAR 影像於分析波場之適用條件及所受之限制。發現當衛星影像灰度值分佈分散，或波浪前進方向 與衛星飛行方向趨於同向時，由 SAR 影像分析所得之主波長、波向與實測值之差異較大，甚至 該影像無法分析。考慮人類活動及海事工程大都於近岸海域實施，本文進一步將 SAR 影像應用 於分析近岸波場，探討造成近岸波場實測值與影像推佑值差異的原因，經本文討論得知近岸海 域水深變化大，空間波場分佈不均，是造成衛星影像之波場特徵值與單點實測值產生差異的原 因之一。 Some Notes on the Nearshore Wave Field Analysis Using SAR Images l 3 4 Hong-Peng Lin Dong Jiing Doong Laurence Z.H. Chuang Chia Chuen Kao ABSTRACT The Synthetic Aperture Radar (SAR) has been proven a useful tool of physical oceanographers studying the ocean. However ，some of images can t reach for satisfied results. One is because the gray value distributions of images are broadened ，i.e. the gray values are too scattered. The other case is when the angle between wave propagation direction and satellite track is too narrow ，the estimated result will be far from the ground truth measured in-situ observation. Several case studies also shown that the wave direction and wavelength estimated from a sub-image are quite different from the field data measured on data buoys in the steep-down shallow water. It may suggest that some of wave information derived from SAR images can not appropriately represent wave character