Activity of High Cyclones above Erebus Volcano According to ERA5 Reanalysis Data

Abstract

The Erebus volcano is the southernmost active volcano on Earth, whose volcanogenic emissions include components which play a significant role in catalytic cycles of stratospheric ozone depletion. High cyclones contribute to the rise of gas emissions from the Erebus volcano (including HCl and SO₂) from the troposphere to the altitudes of ozone hole formation, from 14 to 22 km in the stratosphere. The paper considers the integral content of HCl and ClONO₂ for the period 1992–2023 and analyzes the variability of the frequency of high cyclone occurrence for the period 1980–2022 based on the ERA5 reanalysis data. It is revealed that the maximal frequency of occurrence of high cyclones over the Erebus volcano is usually observed in July. The integral HCl content over Antarctic stations is much higher than over Arctic ones and approximately twice as high as over midlatitude stations. The effect of HCl accumulation in the stratosphere is shown: the coefficient of correlation between 5-year average frequencies of occurrence of high cyclones and 5-year average areas of the ozone hole with a 4-year shift ahead of the series of ozone hole areas relative to the series of high cyclone frequencies, calculated for the period from 1980 to 2022, amounts 0.78.