We are currently in the middle of the dry season in the central Amazon basin, where ATTO is located. This time of year is always characterized by lots of biomass burnings, both natural and anthropogenic. Fires produce aerosols, such as black and brown carbon. But the situation isn’t the same every year.
Our researchers studied the concentration of light-absorbing aerosol particles at ATTO over a 5-year period from 2012 to 2017. They found that the aerosol concentration increased significantly during the El Niño of 2015-2016. During that time, the dry season lasted longer than normal and forest and agricultural fires occurred much more frequently compared to other years. The fires produce large amounts of black and brown carbon. These are able to absorb radiation, which has two important effects: firstly, it warms the atmosphere, and secondly, less radiation is able to reach the canopy and forest floor, thus affecting the primary production of the forest. That means that a climatic shift to warmer and drier conditions and potentially stronger and more frequent El Niños could affect the Amazon rainforest in the future.
First-author Jorge Saturno just published the study in Atmospheric Chemistry and Physics (ACP) Issue 18. It is available Open Access and thus freely available for everyone.