Spatial-temporal evolution analysis of the vegetation in the Chapadinha microregion (Maranhão, Brazil) through remote sensing

Abstract

The Chapadinha microregion, located in the eastern part of the state of Maranhão, Brazil, maintains a large agricultural production, especially soybeans, causing beyond largesse of the economy, which promotes a degradation of large areas of native forests. The analysis of space - temporal with remote sensing images can be a tool for understanding the area and possible decision making of allocated mandates. The objective of this study is to analyze spatial and temporal variation of the micro-Chapadinha, Maranhão, Brazil by remote sensing technique called Normalized Difference Vegetation Index - NDVI for the years 2007, 2010 and 2014. It is used Lands at 5 images - TM and 8 - OLI orbits 220 / 62-63 months of 22/07/2007, 15/08/2010 and 25/07/2014and it being applied processing equations of radiometric radiance, reflectance and NDVI. The NDVI for micro-Chapadinha vegetation indicated a fall of the years 2007 to 2010 and at the same time, an increase in agricultural activity; low NDVI areas that are not exposed in 2007 were observed in 2010, one of the causes of this advent can be the event El Niño in the Northeast. In 2014, vegetation indices showed high in much of the micro-region; the response of this increase may be the reaction of trees was once under water stress the great rainfall that year. The municipalities of Brejo, Milagres of Maranhão and Buriti are the most affected by farming, they still come extending and have propensities to leave the micro limits. Remote sensing responded with great efficiency, but the complexity of the natural environment make it necessary that there interconnections with other indices therefore resulting in a more efficient monitoring and analysis.

Analysis of errors in the digital elevation model - SRTM for the Sobradinho reservoir/BA

“…O sensoriamento remoto também colabora na gestão destas áreas, com o fornecimento das imagens, análises e monitoramento. No geral, essas ferramentas conseguem, na impossibilidade de trabalhos in loco ou em grandes áreas, o diagnóstico e o acompanhamento vegetacional; a geopotencialidade de áreas agricultáveis ou regiões susceptíveis a desertificação, erosão, dentre outros parâmetros (Santos e Galvíncio, 2013;Ferreira et al, 2016;Gomes et al, 2016aGomes et al, , 2016bSilva et al, 2016aSilva et al, , 2016b.…”