ALTERAÇÕES ESPECTRAIS EM ÁREAS DE ABRANGÊNCIA DE ACIDENTES AMBIENTAIS MONITORADAS ATRAVÉS DE IMAGENS ORBITAIS.

The delimitation of an impacted area by pollution environmental accident is a dynamic process. Its calculation by the short term effects is considered undersized by neglecting long term effects that can be manifested long after the accident. This work points to vegetation spectra alterations after four pollution environmental accidents occurred in distinct areas, measured by difference in vegetation indexes (Normalized Difference Vegetation Index (NDVI) and Normalized Difference Infrared Index (NDII)), after and before the events. The indexes were calculated through Landsat 5 and Landsat 7 images. This work shows that impacted areas can be proposed after environmental accidents by changes in vegetation indexes values, with vegetation long term effects as well as vegetation recovering effects being able to be monitored. Although all proposed areas must be confirmed by field examinations, this work indicates priority areas to be examined, processes usually expensive and time-consuming.