Aerosols from the Hunga Tonga eruption have been found in studies of the westerlies over the northern hemisphere.

A worldwide group driven by specialists from the Establishment of Climatic Physical Science (IAP) of the Chinese Foundation of Sciences has distinguished vapor sprayers from the Hunga Tonga ejection on the northern side of the equator’s stratospheric westerlies.

The physical and chemical processes in volcanic plumes can be simulated with the help of this discovery, which was published in Science Bulletin.

In January 2022, the South Pacific Ocean’s Hunga Tonga-Hunga Ha’apai volcano erupted, releasing ash and gas into the atmosphere. Scientists from all over the world were keeping a close eye on the eruption, which was one of the biggest of recent years.

The Sounding Water Vapor, Ozone, and Particle (SWOP) campaign aims to learn more about how atmospheric compositions are distributed over the Tibetan Plateau over time and space. According to Prof. Bian Jianchun, an IAP scientist and SWOP campaign team leader, the capture of the Hunga Tonga eruption’s volcanic aerosols was unexpected.

“The volcanic aerosols from the Hunga Tonga eruption were accidentally recorded by us 12 weeks after it occurred. This is the first instance that I’m aware of in the Northern Hemisphere at the stratospheric westerlies,”

Prof. Bian Jianchun, an IAP scientist and a team leader of the SWOP campaign.

“We have caught the volcanic sprayers from the Hunga Tonga emission 12 weeks after it emitted.” According to Prof. Bian, this is the first time it has been detected in the Northern Hemisphere at the stratospheric westerlies.

Huge vulnerabilities actually exist in grasping the actual properties and developmental course of volcanic vapor sprayers in the stratosphere, especially SO2 oxidation in volcanic crests and mists and the cooperation among debris and sulfate sprayers after volcanic emissions. These uncertainties are lessened by convincing evidence from in-situ measurements made in volcanic plumes, particularly of the microphysical parameters of volcanic aerosols. However, obtaining these parameters is challenging, particularly during volcanic eruptions.

On April 9, 2022, a balloon carrying the Compact Optical Backscatter Aerosol Detector (COBALD) and the Portable Optical Particle Spectrometer (POPS) was launched in Lijiang, Yunan province, as part of the SWOP campaign that was carried out over the Tibetan Plateau. Suddenly, the inflatable caught the size range of volcanic vapor sprayers at 24–25 km.

Particle number densities of approximately 1 cm3 and a size distribution of the aerosol diameter that was larger than the background mode of stratospheric aerosols (0.22–0.42 m) helped identify the Hunga Tonga volcanic aerosol. Between 24 and 25 kilometers, the COBALD backscatter ratios at 455 nm and 940 nm revealed enhanced aerosol signals. Furthermore, estimations showed that the spray and water fume layers were isolated in the Hunga Tonga tuft.

These findings suggest that even thousands of kilometers from the source, volcanic eruptions may have an effect on regional and global atmospheric circulation and climate. The potential components that prompted the partition of spray and water fume layers in the Hunga Tonga crest will be analyzed in a future review.

More information: Jianchun Bian et al, First detection of aerosols of the Hunga Tonga eruption in the Northern Hemisphere stratospheric westerlies, Science Bulletin (2023). DOI: 10.1016/j.scib.2023.03.002

Topic : Article