3. Producción
Browse
2 results
Search Results
- Some of the metrics are blocked by yourconsent settings
Item type:Publication, Sparse representation-based inundation depth estimation using SAR data and digital elevation model(Institute of Electrical and Electronics Engineers Inc., 2022-01-01)Floods increase every year worldwide, and prompt information about the affected areas is essential for early disaster response. There has been extensive development in applying remote sensing data to identify floods. In fact, remote sensing data are the only tool to identify the extent of large-scale floods within hours after their occurrence. However, few studies have addressed methods to estimate inundation depth. Inundation depth can be advantageous for identifying areas where people may need assistance during evacuation and estimating damage loss. We present a practical application of sparse representation that integrates a synthetic aperture radar-based flood binary map with a digital elevation model to estimate inundation depths. We assume that the floodwaters can be modeled as a combination of water bodies at a state of rest. A dictionary of water bodies computed under potential inundation levels is constructed from the digital elevation model. Then, the actual flood extent is represented as a sparse linear combination of the water body dictionary. The inundation depth can be estimated because each water body from the linear combination is associated with an inundation level. To assess our proposed procedure, we computed the inundation depth of the flood in the town of Mabi, Okayama Prefecture, produced during the 2018 heavy rainfall. An average absolute value difference of about 60 cm between our results and a field survey performed by a third party was observed. Two other floods produced by the 2019 Hagibis typhoon were analyzed to illustrate the relevant information that can provide inundation depths. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Long-term variability, extremes and changes in temperature and hydrometeorology in the Amazon region: A review(Instituto Nacional de Pesquisas da Amazonia, 2024-01-01)This review discusses observed hydroclimatic trends and future climate projections for the Amazon. Warming over this region is a fact, but the magnitude of the warming trend varies depending on the datasets and length of the analyzed period. The warming trend has been more evident since 1980 and has further enhanced since 2000. Long-term trends in climate and hydrology are assessed. Various studies have reported an intensification of the hydrological cycle and a lengthening of the dry season in the southern Amazon. Changes in floods and droughts, mainly due to natural climate variability and land use change, are also assessed. For instance, in the first half of the 20th century, extreme flood events occurred every 20 years. Since 2000, there has been one severe flood every four years. During the last four decades, the northern Amazon has experienced enhanced convective activity and rainfall, in contrast to decreases in convection and rainfall in the southern Amazon. Climate change in the Amazon will have impacts at regional and global scales. Significant reductions in rainfall are projected for the eastern Amazon.