| dc.description.abstract | Natural disasters might have become more severely and occur more frequently worldwide due to the influence of global change in recent years. Taiwan, located in the subtropical monsoon climatic zone and arc-continent collision between the Luzon volcanic arc and the Eurasian continent, suffers from the natural disasters, such as drought, flood, geohazard. Its annual precipitation is about 2.5 times higher than the world’s average. Its complex geological terrain, uneven spatiotemporal distribution of rainfall may cause slope disaster and water scarcity. As a result, water supply available to the people per capital is only 20% of the world’s average. Comprehensive investigation is necessary for the decision-makers of natural resources management. However, due to extremely high cost of pointwise exploration with inconvenience in conducting on-site campaign in remote areas, remote sensing technique becomes an alternative solution. To achieve cost effectiveness on groundwater exploration and geohazard analysis, the use of comprehensive remote sensing (RS) data and GIS-based models appears to be feasible.
The results of this study shows that, in the mountainous regions, seven categories of terrains were defined by topographic position index, topographic wetness index and slope degree. Seventeen hydrogeological units were delineated from digital geological maps. Besides, the regional lineament and abnormal surface temperature favorable to groundwater have been considered and derived from remote sensing data. Compared with in-situ well yield data, the accuracy of the interpreted groundwater potential site (GWPS) varied with rock types and terrains. However, assessing the normalized groundwater potential index in the comprehensive RS-GIS model has improved the results to achieve a cost-effective objective in terms of identifying GWPS. The accuracy of the interpretation of groundwater potential sites is improved from 48.6% to 84.7%. In the case of Taichung Basin, integrating GIS, Landsat and MODIS imageries, WetSpass Model successfully provides the interpretation of potential groundwater infiltration. For the research of slope disaster, the soil water content retrieved from ATI-MODIS was considered during typhoon event. It is indicated that the slope area may be triggered as a landslide with increased pore water pressure and reduced effective stress. The comprehensive analysis results provide important information on the disaster prevention and mitigation. | en_US |