バングラデシュ南西部沿岸の地形変化とその要因に関する分析

抄録

Morphological changes of the coastal area along the south-western part of Bangladesh, specially focused on the areas with mangrove forest, have been studied. LANDSAT satellite images were analyzed to detect shoreline positions and a regional overview of coastal accretion and erosion over three time periods, from years 1989 to 2000, 2000 to 2005 and 2005 to 2010, has been obtained. Most of the area suffered from erosion and the rate of shoreline retreat was approximately 80 m / year at maximum. Variation of normalized difference vegetation index derived from satellite data, river discharge, salinity, tide level and wave action has been analyzed to infer possible factors that caused erosion. Salinity of the river water in the dry season seems a critical factor for prevalence of mangrove forest which stabilizes the morphology.