LEONARDO MARTINS MACHADO
Abstract:
Studies related to sanding and sand formation among other environmental impacts associated with degradation of sandy soils in the Goiás southwestern microregion have been carried out since 2002 according to Scopel; Peixinho and Sousa (2005). The sanding process for Suertegaray (1996) apud Sousa et al. (2012) is due to the "reworking of poorly consolidated sandy deposits or unconsolidated sandy soils, which in these areas promotes difficulties in fixing vegetation associated with constant sediment movement". The sands are conceptualized according to Sousa et al. (2012) as being patches of exposed soils resulting from the process of vegetation rarefaction in sandy areas. These authors mention that the conditioning factors of sand formation are associated with recent landscape transformations, with a strong connection with natural elements. Among these, the source material, sandstones of the Botucatu Formation. Still among the conditions that will potentiate the sand and form the sands are the use and management of sandy soils. These processes, in turn, are recent landscape transformations, a consequence of the socioeconomic process of occupation of less productive soils to agriculture, which were observed from the 80's. The methodology used in this research was to identify, map and quantify possible sand and sand areas using remote sensing and geoprocessing techniques. Namely, images from the Landasat8 sensor system were used, from which atmospheric corrections were made by energy balance algorithms, SEBAL method according to Allen et al. (2002). For the process of converting the (ND) values of the Landsat8 sensor system images, the values of radiometric coefficients that are contained in the image metadata were used. In the attempt to identify and map these targets, the results of the calculations were used. NDVI, Albedo at the top of the atmosphere, Surface Albedo and brightness temperature. The best results were obtained by surface Albedo. As benefits, the remote sensing use in this research made it possible to work with an area of 56.111,526 km², with excellent cost benefit to obtain information about possible areas of sand and micro sands. Even in the face of spectral confusion of sands and possible areas of sanding with other targets, it was possible to determine the values of NDVI, Albedo at the top of the atmosphere, surface Albedo and brightness temperature.
