SEASONAL ANALYSIS OF CERRADO VEGETATION BY MEANS OF MODIS DATA IN THE DISTRITO FEDERAL (BRAZIL) - DOI 10.5216/bgg.v36i3.44555

Abstract

This study aims to characterize the seasonal behavior of Cerrado vegetation through vegetation indexes (NDVI and EVI) of the MODIS sensor. The characterization of seasonality was carried out in areas with and without recorded fires. NDVI and EVI vegetation indexes from the MOD13Q1 product were used to build time series. The images date from 2000 to 2015, with a 16-day sampling period. Fourier transformations of time series show that the Cerrado vegetation indexes are largely dominated by the annual cycle. The monthly climatology of vegetation indexes established for the period 2000-2015 is strongly controlled by the rainfall monthly climatology established over the same period. In some years the vegetation indexes show a more dynamic spread during the rainy season (a premature increase and lower amplitude than the average amplitude of climatology), or on the contrary a later and more extensive activity. Dispersion diagrams between vegetation indexes obtained for sites without fire versus the burned sites show a separation of data into three distinct groups: the vegetation indexes of the rainy season, those in the dry season, and finally the indexes with a fire-related signature.

Keywords: EVI, NDVI, precipitation, fire, remote sensing.