An overview of the Amazonian Aerosol Characterization Experiment 2008 (AMAZE-08)

The Amazon Basin provides an excellent environment for studying the sources, transformations, and properties of natural aerosol particles and the resulting links between biological processes and climate. With this framework in mind, the Amazonian Aerosol Characterization Experiment (AMAZE-08), carried out from 7 February to 14 March 2008 during the wet season in the central Amazon Basin, sought to understand the formation, transformations, and cloud-forming properties of fine- and coarse-mode biogenic aerosol particles, especially as related to their effects on cloud activation and regional climate. Special foci included (1) the production mechanisms of secondary organic components at a pristine continental site, including the factors regulating their temporal variability, and (2) predicting and understanding the cloud-forming properties of biogenic particles at such a site. In this overview paper, the field site and the instrumentation employed during the campaign are introduced. Observations and findings are reported, including the large-scale context for the campaign, especially as provided by satellite observations. New findings presented include: (i) a particle number-diameter distribution from 10 nm to 10 Î1/4m that is representative of the pristine tropical rain forest and recommended for model use; (ii) the absence of substantial quantities of primary biological particles in the submicron mode as evidenced by mass spectral characterization; (iii) the large-scale production of secondary organic material; (iv) insights into the chemical and physical properties of the particles as revealed by thermodenuder-induced changes in the particle number-diameter distributions and mass spectra; and (v) comparisons of ground-based predictions and satellite-based observations of hydrometeor phase in clouds. A main finding of AMAZE-08 is the dominance of secondary organic material as particle components. The results presented here provide mechanistic insight and quantitative parameters that can serve to increase the accuracy of models of the formation, transformations, and cloud-forming properties of biogenic natural aerosol particles, especially as related to their effects on cloud activation and regional climate. © 2010 Author(s)

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. © 2009 by the American Geophysical Union. All rights reserved

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. © Copyright 2009 by the American Geophysical Union

The green ocean amazon experiment (GOAMAZON2014/5) observes pollution affecting gases, aerosols, clouds, and rainfall over the rain forest

The susceptibility of air quality, weather, terrestrial ecosystems, and climate to human activities was investigated in a tropical environment. © 2017 American Meteorological Society