Ozone hole over Antarctica soars to one of its largest sizes on record, Hunga Tonga eruption possible cause

On September 16, 2023, a significantly large ozone hole stretched over Antarctica, covering an area of 26 million km³ (10.04 million mi³), prompting a deeper look into the possible causes. The fluctuating size of the ozone hole is a yearly phenomenon, with a notable increase from August to October, and a decrease as temperatures in the southern hemisphere’s stratosphere rise towards the year’s end.

The size of the ozone hole over Antarctica has always been subject to fluctuations, primarily increasing from August to October, and gradually decreasing with the rise of temperatures in the stratosphere of the southern hemisphere towards the end of the year. However, the size of the ozone hole this year has propelled scientists to delve into possible causes, with one speculative factor being the Hunga Tonga-Hunga Ha’apai eruption in January 2022.

The eruption is believed to have injected a substantial amount of water vapor into the stratosphere, which eventually reached the south polar regions post the closure of the 2022 ozone hole. This water vapor potentially facilitated the formation of polar stratospheric clouds where chlorofluorocarbons (CFCs) could react, accelerating the ozone depletion process.

Moreover, the presence of water vapor might have contributed to the cooling of the Antarctic stratosphere, promoting the formation of these clouds, and reinforcing a robust polar vortex, hence a larger ozone hole.

However, it’s important to note that the exact impact of the Hunga Tonga eruption on the Southern Hemisphere ozone hole is still a subject of ongoing research. This is due to the absence of previous instances where such substantial amounts of water vapor were injected into the stratosphere in modern observations.

Copernicus Sentinel-5P satellite, launched in October 2017, has been pivotal in monitoring atmospheric changes. Equipped with an advanced multispectral imaging spectrometer called Tropomi, it accurately detects atmospheric gases and provides crucial data regarding ozone levels. The data, processed at the German Aerospace Center (DLR) and compared with ground-based data, has proven to be accurate at the percentage level, aiding in a close monitoring of the ozone layer and its evolution.

The 2023 ozone hole’s early onset and rapid growth were noted by the Copernicus Atmosphere Monitoring Service (CAMS), with senior scientist Antje Inness emphasizing its early start and rapid expansion since mid-August. This year’s ozone hole is among the largest recorded, raising concerns and urging a comprehensive investigation into the factors contributing to such massive ozone depletion.

As the scientific community delves deeper to understand the underlying causes of this year’s massive ozone hole, the data from Copernicus Sentinel-5P remains instrumental in providing accurate and timely insights into atmospheric changes and ozone depletion patterns. This information is crucial in driving informed decisions and strategies aimed at mitigating the adverse impacts of ozone depletion on the environment.

References:

¹ Ozone hole goes large again – ESA – October 4, 2023

Featured image credit: ESA (stillshot)