O potencial das imagens de satélite no monitoramento e mapeamento de secas

Abstract

This work seeks to investigate the applicability of remote sensing techniques and Geographic Information Systems (GIS or GIS), seeking answers for the monitoring and mapping of droughts, based, above all, on the use of physical principles of electromagnetic waves, through remote sensors of environmental observation satellites. It is intended with the same, to reinforce the basic knowledge about the geographic extension and magnitude of the droughts in Mozambique, to allow the development of information systems and monitoring of droughts, using satellite images combined with the GIS. These images, when combined with Geographic Information Systems (GIS) techniques, have the potential to serve as a powerful tool for detecting and monitoring processes that can result in natural disasters, such as drought. However, the use of this instrument requires knowledge of the empirical relationship between rainfall and vegetation conditions. To study the state of the vegetation, the NDVI (Normalized Difference Vegetation Index) was used, which is a preferred vegetation index for monitoring global vegetation using satellite images from the NOAA (National Advanced Very High Resolution Radiometer) sensor. Oceanic and Atmospheric Administration). It was possible to determine the significant interval for situations of occurrence of droughts, which ranges from 0.23 to 0.37, for the magnitude of the severe to weak type. Drought-prone areas were identified, in the southern region the provinces of Gaza, Inhambane and Maputo, in the central region the provinces of Tete and Sofala and finally in the northern region, the provinces of Niassa, Cabo Delgado and Nampula. Finally, it was established the relationship between Precipitation and NDVI in the period from October to March 1981-2001, and it was concluded that the NDVI shows a direct relationship of the rainfall distribution of a certain studied region.(TRADUÇÃO NOSSA)