Study of Aerosol Optical Depth Temporal Variability Using Remote Sensing Data in a Transition Region Between Amazon Forest and Brazilian’s Savannah

Abstract This work aims to present an observational analysis about the temporal variability of aerosol optical depth (AOD), exploring remote sensing products. It is studied how rain deficits in dry season can impact fire activities in Legal Amazon, and how they could affect the atmosphere’s composition. It is used AOD data from MODIS/Terra sensor and AERONET network station, for precipitation we use TRMM satellite data, and for biomass burning, data products from CPTEC/INPE ranging from 2000 to 2012. Results indicate that AOD values inferred from satellite and AERONET present a negative trend in the last five years, probably associated with changes in the anthropic activities in the region. For the same period, the deforestation rate in Legal Amazon estimated from satellite also present reduction. Satellite data indicate that rain deficit during dry season is one of the possible causes for burn increasing in September, but is not the only factor. The correlation between accumulated precipitation data and burns founded in this study is lower than -0.3. By the other hand, the correlation between precipitation and aerosols is more pronounced (R = 0.7), but explains just part of the AOD variability. Deforestation decreasing on such region could also justify the AOD changes.