European scientists from the Copernicus Atmosphere Monitoring Service explained the causes that have led to this phenomenon in the stratosphere
October 7, 2020 Share on FacebookShare Share on TwitterTweet Share on WhatsAppShare
The Antarctic ozone hole is aggravated by a stable polar vortex (OMM)
For many years we have heard about the ozone layer and the danger that the holes that exist at the poles represent for life on the planet . The ozone layer or ozonosphere is the area of the earth's stratosphere that contains a high concentration of ozone and extends approximately from 15 km to 50 km of altitude.
This layer is important because it gathers 90% of the ozone present in the atmosphere and absorbs 97 to 99% of the low frequency ultraviolet radiation (150-300 nm). Now a group of scientists working in the European Union's Earth observation program revealed that the hole in the ozone layer over Antarctica has grown to its largest and deepest in several years.
Experts from the Copernicus Atmosphere Monitoring Service noted that a strong, stable, cold-air polar vortex has triggered the expansion, and called for redoubled international efforts to ensure nations adhere to an agreement to phase out substance use. chemicals that deplete the ozone layer.
The ozone hole at the South Pole is the largest detected in 15 years – EFE / María Molina / Archive
Vincent-Henri Peuch, who runs the service, said in a statement that the hole in the ozone layer “definitely” was one of the largest in the past 15 years. The depletion of the ozone layer on the Antarctic continent was first captured in 1985.
In Geneva, the spokeswoman for the World Meteorological Organization (WMO), Clare Nullis, added that the hole in the ozone layer normally begins to expand every August, at the beginning of spring in Antarctica, and peaks in October.
” The air has been below minus 78 degrees Celsius , and this is the temperature you need to form stratospheric clouds, and it's quite a complex process,” Nullis said during a UN briefing. He added: “ The ice in these clouds triggers a reaction that can destroy the ozone zone. So that's why we are seeing that big hole in the ozone layer this year. “
The ozone layer is important because it absorbs 97 to 99% of low frequency ultraviolet radiation – EFE / Felipe Trueba / Archive
The Copernicus service claimed that the Sun's energy as it rises over the pole causes the release of chlorine and bromine atoms in the polar vortex, which rapidly destroy ozone molecules, causing the hole to form. Nullis said that despite the hole, experts still believe that the ozone layer is slowly recovering after the adoption of the Montreal Protocol , a treaty signed in 1987 that is aimed at phasing out ozone-depleting substances. He also pointed to projections that the ozone layer will return in 2060 to the levels it had in 1980.
Last April the European Center for Medium-Range Weather Forecasts (ECMWF) reported that the largest ozone hole observed in the Arctic (North Pole), which reached a record size last March, had begun to close, just as scientists from the German Aerospace Center had predicted.
The news about its total closure was recently confirmed by the World Meteorological Organization (WMO), which explained that this phenomenon was caused by the continuous presence of substances such as chlorofluorocarbons (CFCs) in the atmosphere, which destroy the ozone layer, and a very cold in the stratosphere.
“Depletion of the ozone layer, the shield that protects life on Earth from harmful levels of ultraviolet radiation, reached an unprecedented level in large parts of the Arctic this spring. The last time equally strong ozone depletion was observed in the Arctic was during the spring of 2011, ”Nullis said.
The organization also realized that the hole in the ozone layer closed due to the increase in temperatures in the stratosphere (layer of the atmosphere located between 10 and 50 kilometers above sea level), ending the influx of rich air. in ozone from the lower layers of the atmosphere.
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