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Universidade Estadual da Paraíba (UEPB) 2010

Evaluating the process of desertification in semi-arid region of Paraiba using geotechnology

LIMA, Ricardo da Cunha Correia

Titre : Evaluating the process of desertification in semi-arid region of Paraiba using geotechnology

Avaliação do processo de desertificação no semi-árido paraibano utilizando geotecnologias

Auteur : LIMA, Ricardo da Cunha Correia

Université de soutenance : Universidade Estadual da Paraíba (UEPB)

Grade : Mestrado em Ciência e Tecnologia Ambiental – MCTA 2010

Résumé
This paper evaluated the desertification process in the municipality of Juazeirinho, area susceptible to desertification in the state of Paraiba. The Vegetation Cover Area indicator was used to estimate the evolution of this process. For that, images from remote sensing satellite Landsat 5 TM in 1990 and 2005 were processed in order to obtain the Normalized Difference Vegetation Index (NDVI) for the two time points mentioned. Supported by data from soil types, topography and rainfall, a Geographic Information System (GIS) was used to classify the different states of vegetation cover. Segmentation techniques by on growing region were employed on NDVI image and a supervised classification, using the regions Bhatacharya classifier, were applied to define and quantify the areas with the highest degree of degradation of vegetation cover and estimate the rate of progress of human activities on native vegetation. It was found that, in 15 years, the municipality lost an area of forested-shrubby Caatinga equivalent to 35.2 km 2 , a reduction of 17.4% of the existing area in 1990, which corresponds to a deforestation rate of 2.3 km 2 per year. In 2005, both classes of vegetation totalized 168.8 km 2 , that is, only 35.6% of total area of municipality remained covered by native vegetation. In the opposite direction, the areas occupied by Caatinga degraded, agricultural and grazing fields have experienced a growth of 29.9 km 2 , increasing the degraded area up to 295.4 km 2 , or 63% of total area of municipality. Palavras-chave : remote sensing, vegetation cover, NDVI, GIS, sensoriamento remoto, cobertura vegetal, IVDN, SIG.

Mots Clés : Análise ambiental Semi-árido Sensoriamento remoto Desertificação Geoprocessamento Environmental analysis Semi-arid remote sensing Desertification Geoprocessing

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