Análise espacial e detecção de mudanças da cobertura vegetal no município de Santa Rita do Passa Quatro – SP, utilizando os índices NDVI, SAVI, IAF e Temperatura da Superfície

Abstract

Soil changes resulting from human actions have been worrying society for decades, as these changes result in severe climate impacts, especially within cities where temperatures increase significantly. Currently, land cover monitoring can be performed using remote sensing techniques applied to digital images from satellites such as Landsat – 8, used in this work. Through digital image processing it is possible to obtain the Normalized Difference Vegetation Index (NDVI), the Soil Adjusted Vegetation Index (SAVI) and the Leaf Area Index (IAF) to verify the impacts arising from the change in vegetation cover. Surface temperature (TS) was also used to assess changes in land cover. The objective of this work is to analyze differences in the seasonal dynamics of vegetation and TS indices through of remote sensing techniques applied to four orbital images from the Landsat 8 satellite in subsequent years, two relating to the rainy season (23/02/2017, 14/03/2018) and two to the dry season (19/09/2017 22/09) /2018. The study area is the municipality of Santa Rita do Passa Quatro, state of São Paulo, where orbital images (LANDSAT 8) obtained from the United States Geological Survey (USGS) were used. The QGIS 2.14 software was used to calculate the NDVI, SAVI, IAF and TS. The results obtained showed significant variations, where the NDVI values were lower than the SAVI values, due to the applied soil correction. When verifying the changes in vegetation and soil, it was observed that on days where there was precipitation, both NDVI and SAVI had higher values, up to 0.60, while during days without precipitation, the indexes were lower, up to 0 .45 in NDVI, and 0.75 in SAVI. The IAF analysis complemented the NDVI and SAVI analyses, showing higher values in places where vegetation had greater biomass. In the assessment of TS, these were milder in vegetated areas, and in areas of urban mesh and open soil, TS was significantly higher. The TS with the presence of vegetation was 22.58°C and in the urban grid and open soil it was up to 33.0 °C. Thus, the NDVI, SAVI and IAF values in Santa Rita do Passo Quatro – SP vary according to some factors, such as the removal of some planted crops, removal of native vegetation, construction of cities and incident precipitation. And these changes in land cover impact on high TS values.