The volcanic eruption in Tonga creates mysterious atmospheric ripples

Image credit: Lars Hoffmann/NASA

The recent eruption of a volcano in Tonga has triggered a series of puzzling ripples in The Earth's atmosphere, and scientists are stepping up their efforts to study the phenomenon. Satellite data showed that the event triggered an unusual atmospheric gravitational wave that had not been produced by previous volcanic eruptions.

According to Nature, the discovery was collected hours after the eruption of a volcano in Tonga on Jan. 14 by the Atmospheric Infrared Probe (AIRS) aboard NASA's Aqua satellite.

Satellite imagery shows dozens of concentric circles, each representing rapidly moving gas waves in the atmosphere and stretching for more than 16,000 kilometers. These waves reach the ionosphere from the ocean surface, and the researchers believe they may have circled the Earth several times.

Lars Hoffmann, an atmospheric scientist at the Hub for Supercomputing in Jürich, Germany, added: "This instrument has been in operation for about 20 years and we have never seen such a good concentric wave pattern. ”

Atmospheric gravitational waves are produced when air molecules are perturbed vertically instead of horizontally in the column of air. This can happen when the wind accelerates over the top of the mountain, or when the local weather system convects. This up-and-down fluctuation transmits energy and momentum through the atmosphere, and their effects are usually manifested as forming a series of ripples in high clouds.

Theoretically, the hot air and ash produced by volcanic eruptions rise rapidly, potentially triggering larger gravitational waves after entering the upper atmosphere. However, scientists have not observed a similar situation since the launch of the AIRS instrument in May 2002.

Corwin Wright, an atmospheric physicist at the University of Bath in the UK, said: "This is where we really get confused. This must have something to do with the physical phenomenon that is happening, but we don't yet know what that is. ”

Wright's team suspects that the "huge, cluttered hot gas pile" in the upper atmosphere may be the cause of these waves. He believes that hot gases rising into the stratosphere will hit the surrounding air.

The sound of a volcanic eruption in Tonga spread throughout the South Pacific, even in parts of the United States. Volcanic ash has covered much of Tonga, but because of power outages, phone lines and internet connections, it has been difficult for rescue agencies to assess the extent of its casualties and damage.

Wright was the first to discover gravitational wave patterns in data provided by Hoffmann. The images, he says, are like a mixture of waves of different sizes and types. Convection in the atmosphere seems to be very complex and bumpy, and at the same time is producing a series of things. "It's what we think is happening right now, but we've only been looking at it for a few hours." Wright said.

Scott Osprey, a climate scientist at the University of Oxford, said the eruption could be unique in causing these gravitational waves.

The eruption may have lasted for several minutes, but its effects could be long-lasting. In the tropics, gravitational waves interfere with periodic wind reversals, which Osprey believes could affect weather patterns as far away as Europe.

Researchers are closely monitoring further eruptions of the volcano. Shane Cronin, a volcanologist at the University of Auckland in New Zealand, said: "We are just closely following developments. Volcanoes may re-inject large amounts of magma from deep underground, creating larger eruptions. But if it has exhausted its main supply, it may produce only smaller eruptions, most of which are hidden beneath the ocean's surface. (Xin Yu)

Source: China Science Daily