Aerosols from Hunga Tonga in Northern Hemisphere stratospheric winds

2023-05-05 16:34:51

Dr. BAI Zhixuan and his colleagues launched a balloon in Golmud, Qinghai Province, in March 2021, as part of the SWOP campaign. – CHEN Zhixiong

MADRID, 5 May. (EUROPA PRESS) –

Aerosols from the large explosive eruption of Hunga Tonga have been detected for the first time in the stratospheric winds of the northern hemisphere. This discovery, published in Science Bulletinwill help to simulate the physical and chemical processes in volcanic columns.

This natural event spewed ash and gas into the atmosphere. The eruption was one of the largest in recent years and was closely monitored by scientists around the world.

Capturing volcanic aerosols from the Hunga Tonga eruption was unexpectedaccording to Professor Bian Jianchun, a scientist at the IAP (Institute of Atmospheric Physics) of the Chinese Academy of Sciences and leader of the SWOP (Sounding Water vapor, Ozone, and Particle) campaign team.

“We have captured volcanic aerosols from the Hunga Tonga eruption 12 weeks after it erupted. To my knowledge, this is the first time it has been detected in stratospheric westerlies in the northern hemisphere,” said Professor Bian. it’s a statement.

Large uncertainties remain in the understanding of the physical properties and evolutionary process of volcanic aerosols in the stratosphere, in particular the oxidation of SO2 in volcanic plumes and clouds and the interaction between ash and sulfate aerosols after eruptions. volcanic. In situ measurements obtained in volcanic plumes, especially measurements of the microphysical parameters of volcanic aerosols, provide compelling evidence that reduces these uncertainties. However, it is difficult to obtain these parameters, especially during the occurrence of volcanic eruptions.

During the SWOP campaign conducted over the Tibetan Plateau, a balloon-borne payload consisting of the Compact Optical Backscattering Aerosol Detector (COBALD) and the Spectrometer was launched on April 9, 2022 in Lijiang, Yunan Province. of Portable Optical Particles (POPS). Unexpectedly, the balloon captured the size spectrum of volcanic aerosols at 24-25 km.

The Hunga Tonga volcanic aerosol was identified by the aerosol diameter size distribution, which was centered at approximately 0.42-1.27 micrometers, larger than the background mode (0.22-0.42) of the aerosols. stratospheric and particle number densities of about 1 cm to the power of -3. Backscatter ratios derived from COBALD measurements at 455 nm and 940 nm showed enhanced aerosol signals between 24 and 25 km. In addition, the measurements showed that the aerosol and water vapor layers were separate in the Hunga Tonga plume.

These findings suggest that volcanic eruptions have a potential impact on regional and global atmospheric circulation and climate, even thousands of kilometers away from the source. The possible mechanisms that led to the separation of the aerosol and water vapor layers in the Hunga Tonga plume will be examined in a future study.