A recent study on volcanic ash
Volcanic ash affects the atmosphere and may block sunlight
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| volcano |
And a new study from the University of Colorado at Boulder indicates that this volcanic ash could have a bigger impact on the planet's climate than scientists previously thought.
The new study, published in Nature Communications on September 10/2020, examines the 2014 eruption of the Mount Kelut (or Kelud) volcano on the Indonesian island of Java in 2014.
Using real-life observations of the event and advanced computer simulations, the team found that the volcanic ash appears to have peeled off and remained in the air for months or more after a large eruption.
"What we found in this volcanic eruption is that volcanic ash can last for a long time," says Yunqian Chu, lead author of the new study and a research scientist at the Laboratory of Atmospheric and Space Physics (LASP) at the University of Colorado.
The discovery began with a note of accident, as members of the research team were flying a drone near the site of the Mount Kilut eruption - an event that covered large parts of Java with ash and prompted people to leave their homes. "They saw some large, ash-like particles floating in the atmosphere a month after the explosion," Chu says.
She explained that scientists have known for a long time that volcanic eruptions can negatively affect the planet's climate, as they explode with huge quantities of sulfur-rich particles in the Earth's atmosphere and can prevent sunlight from reaching the Earth.
However, the researchers did not believe that the ash could play such a large role, as scientists speculated that these pieces of rock debris were so heavy that most of them probably fell from the volcanic clouds soon after. an eruption.
Drawing on aerial and satellite observations of the disaster, the team found that the volcano's plume appears to be filled with tiny particles of light ash - tiny particles that can float in the air for long periods of time, like dandelion fluff.
“The researchers speculated that the ash looked like obsidian ... but what we found is that this float has a density that is very similar to pumice,” Chu said. Pumice is a light, porous glassy volcanic rock that fills with holes created by gas bubbles trapped as it hardens.
The disappearance of the particles.
Ton, a professor in the Atmospheric and Space Physics Laboratory and Department of Atmospheric and Oceanic Sciences at the same university, explained that erupting volcanoes eject a large amount of sulfur dioxide.
The researchers previously speculated that these molecules interact with other particles in the air and turn into sulfuric acid, in a series of chemical reactions that can theoretically take weeks.
But the factual observations indicate that it is happening much faster than that. “There was a mystery as to why these reactions happened so quickly,” Ton says.
Ton and his colleagues believe they have found the answer: these particles of sulfur dioxide seem to stick to particles of ash floating in the air. In the process, it can undergo chemical reactions on the surface of the ash itself, which could cause about 43% of the sulfur dioxide to be removed from the air.
The researchers previously speculated that these molecules interact with other particles in the air and turn into sulfuric acid, in a series of chemical reactions that can theoretically take weeks.
But the factual observations indicate that it is happening much faster than that. “There was a mystery as to why these reactions happened so quickly,” Ton says.
Ton and his colleagues believe they have found the answer: these particles of sulfur dioxide seem to stick to particles of ash floating in the air. In the process, it can undergo chemical reactions on the surface of the ash itself, which could cause about 43% of the sulfur dioxide to be removed from the air.
In other words, ash can accelerate the conversion of volcanic gases in the atmosphere. So what is the impact of these ash clouds on the climate? It's unclear. Long-lived particles in the atmosphere could, in theory, darken the planet and even help cool it after it erupts.
Float ash can also explode en route between sites such as mount Kiloot and the poles of the planet. There, it could set off chemical reactions that would destroy the Earth's most important ozone layer.
But researchers say one thing is clear: When volcanoes erupt, it is time to pay more attention to all this ash and its true impact on Earth's climate.