Ozon hole over Antarctica larger than ever
Recent measurements of the ozone hole over Antarctica shwos a record breaking size according to a report by the European Space Agency (ESA). The ozone hole was recorded by the Copernicus Sentinel-5P satellite. On September 16, 2023, its extent reached an astonishing 26 million square kilometers, about three times the size of Brazil.
High resolution imaging
The satellite, which was launched on October 13, 2017 as the European Union’s first Copernicus satellite to monitor the atmosphere, is equipped with a state-of-the-art multispectral imaging spectrometer called “Tropomi.” The instrument improves atmospheric monitoring capabilities by identifying different ‘fingerprints’ of various gases in different segments of the electromagnetic spectrum. This allows more precise and high-resolution imaging of a wide range of contaminants.
The data from the “Tropomi” are carefully processed at the German Aerospace Center (DLR) using algorithms developed jointly by DLR and the Royal Belgian Institute of Space Aeronomy (BIRA-IASB).
Tropomi measurements
“The Sentinel 5P total ozone products have percentage accuracy compared to ground-based data and allow us to closely monitor the ozone layer and its evolution,” said DLR senior scientist Diego Loyola.
“The Tropomi measurements extend the global ozone dataset of European satellite sensors by nearly three decades.”
Significant data from Sentinel-5P will be made available to the Copernicus Atmosphere Monitoring Service (CAMS) within three hours of the measurement. This rapid delivery helps CAMS efficiently integrate the data into its analysis and forecasting systems.
One of the largest holes of all time
“On September 16, it reached a size of more than 26 million square kilometers, making it one of the largest ozone holes ever. The ozone data from “Tropomi” are an important data set for our ozone analysis,” says Dr. Antje Inness, senior scientist at CAMS
Understanding the reasons for the substantial size of the ozone hole is complex. Its size variations are closely related to the strength of strong wind bands circulating around Antarctica, a phenomenon resulting from the Earth’s rotation and the temperature differences between polar and temperate latitudes.
Strong wind bands act as barriers, trapping and cooling air masses over polar regions, affecting the size of the ozone hole. The recent unusual ozone patterns may also be related to the Hunga Tonga-Hunga Ha’apai volcanic eruption in January 2022, which contributed significant amounts of water vapor to the stratosphere, experts suggest.
Hunga Tonga eruption
“The eruption of the Hunga Tonga volcano in January 2022 ejected a lot of water vapor into the stratosphere, which did not reach the south polar regions until after the ozone hole ended in 2022,” Antje Inness explained.
“The water vapor may have led to the enhanced formation of polar stratospheric clouds in which chlorofluorocarbons (CFCs) can react and accelerate ozone depletion. The presence of water vapor may also contribute to the cooling of the Antarctic stratosphere, further promoting the formation of these polar stratospheric clumps and leading to a more robust polar vortex.”
However, further investigation is needed to understand the exact impact of this burst on the ozone hole, as there are no precedents in modern observations for such significant water vapor bursts into the stratosphere.
Sentinel 5P monitoring is crucial
“The Sentinel 5P total ozone columns provide an accurate way to monitor the occurrence of ozone holes from space. “Ozone hole phenomena cannot be readily used to monitor global ozone changes because they are determined by the strength of regional wind fields flowing around polar regions,” said Claus Zehner, ESA mission manager for Copernicus Sentinel-5P.
In addition, the presence of ozone-depleting substances, especially chlorofluorocarbons (CFCs), in the atmosphere still poses a significant threat to the ozone layer. These substances were widely used in various products in the 1970s and 1980s, but were phased out under the 1987 Montreal Protocol.
Although the ozone layer is expected to gradually recover and projections indicate a return to normal levels by about 2050, monitoring and analysis remain critical.
With advanced instruments like “Tropomi” on the Sentinel-5P satellite, scientists can now observe atmospheric changes with unprecedented accuracy and resolution, contributing valuable data to ongoing global efforts to understand and protect Earth’s atmosphere.
Press Release European Space Agency
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