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

青山 定敬 西川 肇 村井 宏

出版者

The Remote Sensing Society of Japan

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.10, no.4, pp.539-551, 1990-12-30 (Released:2009-05-22)

参考文献数

18

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It is very important to obtain the information on soil physical properties and the growth condition of trees, when we make runoff analysis in forest land. But actual vegetation map is not including the growth condition of trees, and it is difficult to obtain the information on the soil. Therefore, it is thought that the usefulness of satellite data have to be verified in this aspect.This paper aims at estimating the ratio of coarse pore, which relates to hydrologic cycle in forest using satellite data and applying it to flood-runoff analysis. In mountainous terrain, it is necessary to eliminate the terrain effect to radiometrical distortion for satellite data. Therefore, the radiometrical distortions of used LANDSAT/TM data were eliminated using digital terrain model (DTM). Many measurement points were selected in the area for survey of various physical soil properties and vegetation conditions of the forest.In order to estimate the ratio of coarse pore from satellite data, we made linear multiple regression equation through multiple regression analyses on the relationship between the ratio of coarse pore and corrected LANDSAT/TM data to each of categorized three forest types. As the result, it was found that the ratio of coarse pore related to the band ratio of near-infrared/red. Further, we tried to apply the estimated ratio of coarse pore to runoff simulation model. It was found that this method was useful to estimate the ratio of coarse pore, because of the simulated hydrograph well coincide with the observed one.