Uso de técnicas do sensoriamento remoto para análise da vegetação e do uso e ocupação do solo na sub-bacia do Rio Taperoá, Estado da Paraíba

Abstract

The semiarid region is characterized by it’s low rainfall index, rain concentration in a short period of time, being inserted in the caatinga biome, presents shallow soil, the presence of intermittent rivers, among other characteristics. Due to the history of land use and occupation of the region, which caused the exchange of native vegetation for agricultural uses, the continuous and crescent soil degradation is observed and for this reason the increasing of the desertification process. Another factor that contributes for soil degradation and caused by the subsistence situation of the population in the region is the intense vegetation suppression mainly used as firewood for domestic purposes. Therefor, for the diagnostics and identification of desertification nucleus in the semiarid region it is necessary the study of the dynamics of the land use and occupation in the Taperoá river sub-basin. With the aid of Remote Sensing techniques, use of GIS and spatial analysis. Using these technologies and the creation of thematic maps, soil cover, vegetation index (NDVI) and surface temperature data were analyzed using satellite images from the time interval between 1998 and 2018 of the TM sensor Landsat 8, 7 and 5. This mapping allowed the understanding of the dynamics of land use and occupation in the basin and its level of degradation through the comparison between the variables studied in the determined time. The NDVI data were divided into classes of values ranging from -1 to 1 and are divided into different types of land use ranging from soil exposed to tree vegetation. These data were presented in tables and graphs that demonstrate how much the dynamics of soil use and occupation varied and how much the vegetation density varied in the interval of 20 years. Thus, after comparing the soil use, NDVI and surface temperature data it was possible to diagnose the soil use dynamics and to identify two desertification nuclei in the basin