NDVI WAVELET SPECTRAL ANALISYS IN 2007 – 2009, IN SÃO PAULO STATE REGION (BRAZIL)

Abstract

The objective of this research is the detection ofoscillations of the Normalized Difference Vegetation Index(NDVI) in the northern part of São Paulo State (NSP) andSão Paulo city (SP) regions. Wavelet analysis (WA) isapplied for the 2007-2009 daily dataset period. In this sense,the NDVI WA provides results from the weekly to annualband and allowed the investigation of the spectra and scaleinteraction. The results for the NSP region indicate there isa strong influence of the annual cycle, followed by the semiannualband (especially in Franca region). It is alsoobserved, in some cases, the interaction between the semiannual,intraseasonal and synoptic scales, particularlyduring extreme events. On the other hand, striking resultsconcerning SP city are the more energetic bands in the semiannualto intraseasonal scales. The WA turns to be useful forthe formulation of conceptual models also in the ecologicalfield.Index Terms ⎯ NDVI variability, spectral analisys,wavelets; Sao Paulo State (Brazil).