PLANETARY-SCALE RESPONSE OF AEROSOLS TO THE TONGA VOLCANO ERUPTION

Subject and Purpose. The work is aimed at analyzing changes in the concentration of atmospheric aerosols that were observed not only in the regions within a close vicinity of the eruption (particularly, in Australia), but in polar regions of the Earth as well. Methods and Methodology. To study the dynamical variations of aerosol concentration that had resulted from the eruption of the Tonga volcano, we used data from the global aerosol monitoring network (AERONET) which relies on operation of the automatic, unified solar photometers Cimel CE318 of France. Three-year data sets (2021–2023) of aerosol optical thicknesses (AOT) were analyzed, measured about the spectral line of 440 nm (and, in one case, 443 nm). These data sets are hereinafter referred to as AOT440 or AOT443, respectively. Results. The emissions from the volcanic eruption reached the east coast of Australia on January 17, 2022, arriving to the west coast two days later. We have presented here time dependences of AOТ variations as recorded at two AERONET stations located on the emission track. The average air mass transfer rate has also been calculated. In addition, the paper shows variations in the level of aerosol concentration in the atmosphere of polar and tropical regions that occurred as a result of the Tonga volcano eruption. In addition, eruption transportation rates have been calculated for tropical regions around the globe. Conclusions. As was found, emissions from the Tonga volcano took only two days to reach the east coast of Australia, causing the AOT440 there to increase from 0.15 to 2. Over the two days that followed, the volcano's emissions moved, together with air masses, toward the west coast of the continent where the AOT443 increased from 0.15 to 1. Further on, the aerosols moved toward the AERONET Maido OPAR point over yet another day, and the AOT440 increased from 0.05 to 0.5. The variations in the level of aerosols in the polar regions’ air were also analyzed with the use of data of 2021 to 2023 observations at a few monitoring stations. It was found that the value of AOT440 for the Antarctic region increased in 2023 by a factor of 2 to 3 on the average. Meanwhile, the Arctic region reported a one and a half to two times increases in 2023. As has been established, the zonal transport of aerosols occurred at a very fast rate, while the meridional transport was slow, reaching its peak value for the polar regions over nearly a year.