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  • Wavelet analysis of MODIS t...
    Galford, Gillian L.; Mustard, John F.; Melillo, Jerry; Gendrin, Aline; Cerri, Carlos C.; Cerri, Carlos E.P.

    Remote sensing of environment, 02/2008, Letnik: 112, Številka: 2
    Journal Article

    Since 2000, the southwestern Brazilian Amazon has undergone a rapid transformation from natural vegetation and pastures to row-crop agricultural with the potential to affect regional biogeochemistry. The goals of this research are to assess wavelet algorithms applied to MODIS time series to determine expansion of row-crops and intensification of the number of crops grown. MODIS provides data from February 2000 to present, a period of agricultural expansion and intensification in the southwestern Brazilian Amazon. We have selected a study area near Comodoro, Mato Grosso because of the rapid growth of row-crop agriculture and availability of ground truth data of agricultural land-use history. We used a 90% power wavelet transform to create a wavelet-smoothed time series for five years of MODIS EVI data. From this wavelet-smoothed time series we determine characteristic phenology of single and double crops. We estimate that over 3200 km 2 were converted from native vegetation and pasture to row-crop agriculture from 2000 to 2005 in our study area encompassing 40,000 km 2. We observe an increase of 2000 km 2 of agricultural intensification, where areas of single crops were converted to double crops during the study period.