GISとリモートセンシングを用いたバングラデシュ・ブラマプトラ川の動態解析(<特集>海外地形調査におけるGIS/RSの活用)

概要

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This study analyzes spatial and temporal changes in channel distribution in the large, sandy, braided system of the Brahmaputra River, Bangladesh, using GIS and remote sensing. Supervised classification of satellite images within the braided-belt (channels and bars between the banklines) provided raster land cover data for 14 different years since 1967. Using the data, braided-belt width, the number and width of channels, and the distributions of land cover attributes as well as land stability change were examined. The results indicate that the recent history of the behavior of the Brahmaputra can be divided into four time periods: 1) late 1960s to early 1970s; 2) mid 1970s to early 1980s; 3) mid 1980s to early 1990s; and 4) mid 1990s and later. The distribution of river channels and land use in Period 4 has been the most organized or least complex, suggesting dynamic equilibrium. The channel and land use distribution during Period 2 was relatively organized reflecting quasi-dynamic equilibrium. Periods 1 and 3 were less organized or the most complex and they can be regarded as transitional phases. Frequent large floods may have been the trigger for significant changes in the river system during Periods 1 and 3.
日本地形学連合の論文
2006-04-25