Airborne measurements made as part of the Green Ocean Amazon experiment (GOAmazon) show that the Amazon rainforest emits at least three times more isoprene than scientists had previously thought. The research findings were published in Nature Communications.
According to Paulo Artaxo at the University of São Paulo's Physics Institute (IF-USP) in Brazil and a co-author of the study, isoprene is one of the main precursors of ozone in the Amazon, and it indirectly influences the balance of greenhouse gases in the atmosphere.
"The discovery explains a number of puzzles, such as the high concentration of ozone found downwind of Manaus that couldn't be due to anthropic action," said Artaxo, principal investigator for the FAPESP-funded Thematic Project "GOAmazon: interactions of the urban plume of Manaus with biogenic forest emissions in Amazonia."
Launched in 2014, GOAmazon is investigating the effects of urban pollution from Manaus on cloud formation in the Amazon, among other phenomena. The project also aims to extend knowledge of rain formation processes and the dynamics of interaction between the Amazon's biosphere and the atmosphere. Scientists plan to use the findings to estimate future changes in the region's radioactive balance, energy distribution and climate, as well as the impact of all these factors on global climate change.
Previous estimates were based on measurements made using satellites or forest towers up to 60m in height. During the GOAmazon scientific campaign, however, it was possible to collect new data using the Grumman Gulfstream 1, a research aircraft capable of flying at 6,000 meters, or nearly 20,000 ft, and owned by the Pacific Northwest National Laboratory (PNNL) in the United States.
The airborne measurements were made in 2014 and 2015 during both the rainy and the dry seasons; the measurements were subsequently compared with data collected at ground level. "With measurements taken at 4,000 meters, it was possible...
(Excerpt) Read more at: phys.org