A recent study by researchers at the Pacific Northwest National Laboratory shows that plant-foliage-derived gases drive an atmospheric phenomenon over the Amazon rainforest.
There are important applications for the findings.
The tropical Amazon rainforest constitutes the lungs of the Earth, and this study connects natural processes in the forest to aerosols, clouds and the Earth's radiative balance in ways that have not been previously recognized.
The findings were published in a journal.
The missing data gap was filled.
The team was studying fine particles in the upper atmosphere when they discovered a large discrepancy between their measurement and what was expected. The team found that there were missing forest-atmosphere interactions that govern the amount of fine particles in the upper atmosphere.
The researchers discovered a previously unrecognized process involving semi-volatile gases that are emitted by plants throughout the Amazon rainforest and transported into the upper atmosphere by clouds. Fine particles can be formed from natural carbon-based chemical compounds in the upper atmosphere. The process is very efficient at producing fine particles at high altitudes. These fine particles cool the planet by reducing the amount of sunlight reaching Earth, and they also seed clouds that affect precipitation and the water cycle.
We can't explain the presence and role of key particle components at high altitudes without a full understanding of the semi-volatile source of organic gases.
The discovery of atmospheric processes is very important.
The research project funded by the DOE was about the formation of isoprene epoxydiol secondary organic aerosols, which are measured by aircraft flying at different altitudes.
The region of the atmosphere extending from Earth's surface to approximately 20 kilometers in altitude above tropical regions is called the troposphere. The models did not account for these particles and their influence on the clouds.
As models wouldn't predict the observed loadings at 10 to 14 kilometer altitudes in the Amazon, we were getting what I believed to be either model failures or a lack of understanding of the measurements.
The data was collected by the G-1 aircraft, which was flown up to 5 kilometers in altitude. The team compared the data collected by the German aircraft known as the High Altitude and Long Range Research Aircraft, or HALO, which is flown at altitudes reaching 14 kilometers. The projected loadings of IEPOX-SOAs should have been at least an order of magnitude lower than what was measured. He and his colleagues could not explain what the models projected.
Prior to the team's research, it was believed that the formation of IEPOX-SOAs was the result of multiphase atmospheric chemistry pathways involving reactions of isoprene in the gas phase and particles containing liquid water. The upper troposphere has extremely cold temperatures and dry conditions that do not allow atmospheric chemistry pathways to create IEPOX-SOAs. Liquid water is not available at that altitude. Researchers were unable to explain their formation at 10 to 14 kilometers in altitude using available models.
To understand the mystery, the researchers combined specialized high-altitude aircraft measurements and detailed regional model simulations conducted using supercomputing resources. The undiscovered component of atmospheric processes was revealed in their study. The cold upper troposphere is home to a semi-volatile gas called 2-methyltetrol. The particles that are detected by the aircraft are formed when the gas condenses.
This discovery aids in our understanding of how these fine particles are formed, and therefore shines a new light on how natural processes in the forest cool the planet and contribute to clouds and precipitation.
The doors will be opened to further atmospheric research.
The team has only scratched the surface of the process that affects the formation of fine particles in the atmosphere. He said the process from plants could explain a lot of atmospheric particle phenomena.
This is just the beginning of what we know and will open new frontiers of research in land-atmosphere-aerosol-cloud interactions.
More information: Manish Shrivastava et al, Tight Coupling of Surface and In-Plant Biochemistry and Convection Governs Key Fine Particulate Components over the Amazon Rainforest, ACS Earth and Space Chemistry (2022). DOI: 10.1021/acsearthspacechem.1c00356 Citation: Amazon rainforest foliage gases affect the Earth's atmosphere (2022, April 6) retrieved 6 April 2022 from https://phys.org/news/2022-04-amazon-rainforest-foliage-gases-affect.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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