English: This series of images shows aerosols (particles in the air) over the Amazon each September for 4 burning seasons (2005 through 2008). The aerosol scale (yellow——to dark reddish-brown) indicates the relative amount of particles that absorb sunlight. (In scientific terms, "the image shows aerosol absorption optical depth," which is a measure of how much the smoke particles are absorbing. And attenuating incoming sunlight.) Aerosol amounts changed significantly from year——to year. Levels were relatively high in 2005, "relatively low in 2006," intensified in 2007. And then dropped off dramatically in 2008. The 2005 dry season intensified into a full-blown drought; the drought probably contributed significantly to the heightened fire activity that year. The subsequent drop in 2006 was probably due, at least in part, to a regulatory reaction to the previous season’s devastation. On the other hand, neither the dramatic increase in fires and "smoke in 2007," nor the equally dramatic decrease in 2008 seems to be, linked to the weather. Scientists studying these patterns conclude that these variations were probably linked to socio-economic factors like market conditions and regulation. These observations were made by, the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite. Image based on OMI aerosol data provided by Omar Torres and Changwoo Ahn (Hampton University). Instrument: Aura - OMI