著者

大木 真人 夏秋 嶺 青山 定敬 田殿 武雄

出版者

一般社団法人 日本リモートセンシング学会

雑誌

日本リモートセンシング学会誌 (ISSN:02897911)

巻号頁・発行日

pp.2021.075, (Released:2022-04-16)

参考文献数

27

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Increasing human and economic losses due to urban floods demand rapid flood monitoring using synthetic aperture radar (SAR). In a global first, this study conducted simultaneous experiments using a flood experimental field that can reproduce the conditions of submerged buildings and satellite monitoring using the L-band SAR aboard the Advanced Land Observing Satellite-2 (ALOS-2). Through these experiments, we investigated the relationships among the threshold of interferometric coherence, the accuracy of urban flood detection, the multi-look number in interferometric processing, and floodwater depth. To achieve a better understanding of our experimental results, we also performed theoretical coherence simulations. Our results revealed that the coherence and flood detection accuracy statistically depends on the multi-look number and that 3×3 looks are needed to obtain reasonable accuracy. We also found that coherence-based change detection can detect urban floods with a depth of as little as 6 cm. There was no clear correlation between coherence and water depth. We also performed urban flood detection using ALOS-2 data from observed flood events; the results proved the validity of our theory and its applicability to actual disaster activities. Our findings enable robust urban flood monitoring and contribute to disaster prevention and mitigation.SAR, PALSAR-2, disaster monitoring, flooding, interferometry

著者

夏秋 嶺 穴原 琢摩 琴浦 毅 岩塚 雄大 冨井 直弥 片山 裕之 西畑 剛

出版者

公益社団法人 土木学会

雑誌

土木学会論文集B3(海洋開発) (ISSN:21854688)

巻号頁・発行日

vol.72, no.2, pp.I_748-I_753, 2016 (Released:2016-08-30)

参考文献数

3

被引用文献数

1

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衛星搭載型合成開口レーダー(SAR)は,天候に左右されずに数十キロ四方の広範囲に位置する観測対象を一度に観測できる強みを持つ.SAR 画像の干渉解析は,二回の観測の間に生じた地盤高の変動を数センチ単位で計測できる性能を持ち,これまで地殻変動や被災域の検知を目的として研究されてきた.著者らは,陸域観測技術衛星「だいち2号」(ALOS-2)を利用し,SAR干渉解析による災害時の港湾の被害状況を迅速に把握するべく研究を進めている.本稿では,港湾施設を模した消波ブロック列を用い,干渉解析の適用可能性を検討し,標準偏差で約2 cmの精度を得たほか,平成26年台風第11号により被災した兵庫県神戸市の長田港および須磨港の防波堤の被災領域の検出を試みた結果についても報告する.

著者

夏秋 嶺 渡邉 学 大木 真人 本岡 毅 鈴木 新一 島田 政信

出版者

社団法人 日本リモートセンシング学会

雑誌

日本リモートセンシング学会誌 (ISSN:02897911)

巻号頁・発行日

vol.37, no.1, pp.1-12, 2017-01-31 (Released:2017-08-23)

参考文献数

20

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In this paper, we evaluate the potential accuracy for the volcanic ash coverage using interferometric coherence of the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) aboard the Advanced Land Observing Satellite-2 (ALOS-2, “DAICHI-2”). In order to detect the disaster affected area from interferometric coherence, we require pre-disaster and co-disaster pairs. That is, we require at least two interferometric archives taken before the disaster in addition to one archive after the disaster. The ideal multi-temporal analysis is performed with of course, highest resolution pairs. However, we do not always have enough number of the archive especially in the early stage of the satellite mission. Here, we use not only Stripmap but also ScanSAR mode archive in order to achieve enough number of pairs. The combination of the Stripmap and ScanSAR archives will help to increase the interferometric pair while it suffers the spatial resolution and coherency. Especially for ALOS-2 PALSAR-2 data, it has not been evaluated the potential accuracy of such Stripmap-ScanSAR interferometry method. In this paper, we use the volcanic eruption event in May 2015 at Kuchinoerabu-jima Island, Kagoshima prefecture, Japan for the case study. We evaluated the proposed method with the truth data which was achieved by manual classification using aerial photography. Experimental results showed that the proposed method marked approximately 91% overall accuracy with 0.64 Kappa coefficients to detect the dense volcanic ash coverage.