USO DE MODELOS DIGITAIS DE ELEVAÇÃO (MDE) GERADOS A PARTIR DE IMAGENS DE RADAR INTERFEROMÉTRICO (SRTM) NA ESTIMATIVA DE PERDAS DE SOLO

Abstract

Considering the advances in the generation of Remote Sensing products, this work proposes the utilization of DEM derived from Interferometric radar images (SRTM) to generate one of the factors of USLE, the length-slope factor (LS). This factor considers the relation between the length of the hillside and its slope. Usually, it’s generated from the digitizing of topographic maps contours. The chosen area was Córrego Cachoeirinha watershed, located in the cities of Cáceres and Porto Estrela/MT. Maps of rainfall erosivity, soil erodibility, length-slope factor, land cover and conservation practices have been made. It generated two maps of LS factor, one from the hypsometry and another from the Digital Elevation Model (DEM) obtained from the SRTM images. These maps were made and crossed in the software ArcGis, generating maps of soil losses, which were quantified and compared, according to the classification proposed by FAO, UNEP and UNESCO (1980). Analyzing the LS Maps, the model generated by SRTM showed larger details of the slope shape, that shows a bigger definition offered by that product and less time in the production of soil losses maps, since it avoids not only the job of the hypsometric digitizing, but also the DEM generation from the contours. This proposal of methodology changing aims the execution of environmental analyses in areas that do not own compatible systematic mappings up to 1:100.000 scale.

Keywords

• SRTM
• USLE
• length-slope factor
• environmental fragility
• BAP/MT.