Measurements from the Copernicus Sentinel-5P satellite have revealed that the ozone hole over Antarctica in 2023 is one of the largest on record. This depletion, a massive area referred to by scientists as an ‘ozone-depleting zone,’ reached a staggering size of 26 million square kilometers on September 16, 2023, approximately three times the area of Brazil.
Understanding Ozone Hole Fluctuations
The size of the ozone hole experiences regular fluctuations. It typically expands from August to October, reaching its maximum extent between mid-September and mid-October. As temperatures in the stratosphere rise in the southern hemisphere, the ozone depletion slows down, the polar vortex weakens, and eventually breaks down. By the end of December, ozone levels return to normal.
Launched in October 2017, the Copernicus Sentinel-5P satellite, short for Sentinel-5 Precursor, represents the first Copernicus satellite solely dedicated to monitoring Earth’s atmosphere. Part of the European Union’s environmental monitoring program, it is equipped with an advanced multispectral imaging spectrometer called Tropomi. This instrument can detect atmospheric gases’ unique signatures across the electromagnetic spectrum, offering a more precise and higher-resolution view of various pollutants.
Diego Loyola, a senior scientist at the German Aerospace Center (DLR), highlighted the accuracy of the Sentinel-5P total ozone measurements, which closely align with ground-based data. This precision allows scientists to monitor the ozone layer’s condition and evolution. Tropomi’s measurements extend the global ozone data record of European satellite sensors spanning nearly three decades.
The Copernicus Atmosphere Monitoring Service (CAMS), implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Union, receives Sentinel-5P’s near-real-time ozone data within three hours of measurement. CAMS uses this data in its analysis and forecasting system to provide valuable ozone insights.
The ozone hole’s size is primarily determined by the strength of a powerful wind band encircling Antarctica. This wind band, a result of Earth’s rotation and temperature differences between polar and moderate latitudes, acts as a barrier, isolating air masses over polar regions and cooling them during the winter.
Possible Influence of Volcanic Activity
While it’s too early to definitively attribute the current ozone patterns, some researchers speculate a connection with the eruption of the Hunga Tonga-Hunga Ha’apai volcano in January 2022.
This eruption injected substantial water vapor into the stratosphere, reaching the southern polar regions after the 2022 ozone hole had ended. Water vapor could enhance the formation of polar stratospheric clouds, where chlorofluorocarbons (CFCs) contribute to ozone depletion, and contribute to cooling the Antarctic stratosphere, reinforcing the polar vortex.
The impact of the Hunga Tonga eruption on the Southern Hemisphere ozone hole remains a topic of ongoing research, as such a significant injection of water vapor into the stratosphere has not been observed in modern records.
Montreal Protocol and Ozone Layer Recovery
The widespread use of harmful chlorofluorocarbons in the 1970s and 1980s damaged the ozone layer, resulting in the ozone hole above Antarctica. The Montreal Protocol, established in 1987, aimed to protect the ozone layer by phasing out the production and consumption of these substances. As a result, the ozone layer was gradually recovering.