GEOPHYSICAL MONOGRAPH SERIES, VOL. 186, PP. 233-250, 2009
Aerosol particles in Amazonia: Their composition, role in the radiation balance, cloud formation, and nutrient cycles
The atmosphere above tropical forests plays a very active part in the biogeochemical cycles that are critically important
for the processes that maintain the ecosystem, including processes involving the vegetation, soil, hydrology, and atmospheric
composition. Aerosol particles control key ingredients of the climatic and ecological environment in Amazonia. The radiative
balance is strongly influenced by the direct and indirect radiative forcing of aerosol particles. Nutrient cycling is partially
controlled by dry and wet deposition of key plant nutrients. It was observed that the aerosol particles that act as cloud
condensation nuclei influence cloud formation and dynamics, having the potential to change precipitation regimes over Amazonia.
The 10-year-long record of aerosol optical thickness measurements in Amazonia shows a strongly negative radiative forcing
of −37 W m−2 averaged over 7 years of dry season measurements in Alta Floresta. There is a strong influence of biomass-burning aerosols
on the cloud microphysical properties during the dry season. The connections between the amount of aerosol particles and carbon
uptake trough photosynthesis highlighted the close connection between forest natural processes and the aerosol loading in
the atmosphere. Climate change combined with socioeconomic drivers could alter significantly the emission of trace gases,
aerosols, and water vapor fluxes from the forest to the atmosphere. It is a vital task to quickly reduce Amazonian deforestation
rates, and to implement solid and long-term conservation policies in Amazonia.
Citation: Artaxo, P. et al. (2009), Aerosol particles in Amazonia: Their composition, role in the radiation balance, cloud formation, and nutrient cycles, in Amazonia and Global Change, Geophys. Monogr. Ser., vol. 186, edited by