While the ozone hole over Antarctica generally grows in September and October, scientists have observed the smallest ozone hole since they first observed it in 1982. This emerges from a joint publication by NASA and NOAA.
Unusual weather patterns in the upper atmosphere limited the breakdown of ozone, the layer in our atmosphere that acts as a sunscreen and protects us from ultraviolet radiation.
On September 8, the ozone hole reached a culmination of 6.3 million square kilometers Then he shrank according to the report to less than 3.9 million square miles. Normally, the hole would increase to 8 million square miles.
"It's great news for ozone in the southern hemisphere," said Paul Newman, chief geoscientist at NASA's Goddard Space Flight Center. "But it's important to realize that what we see this year is due to warmer stratospheric temperatures ̵
The annual ozone hole forms when the sun's rays interact with ozone and artificial compounds such as chlorine and bromine to break down ozone, according to NASA. This happens in late winter in the southern hemisphere.
Cloud particles in the cold stratosphere lead to reactions that destroy ozone molecules that consist of three oxygen atoms. In warmer temperatures, however, these clouds do not form, which limits the ozone destruction.
According to NASA, this is the third time in 40 years that warm weather caused by weather systems has contributed to the ozone hole's limitation. This also happened in 1988 and 2002. However, the scientists claim to have found no correlation between the patterns and climate change.
"It's a rare event we're still trying to understand," Susan Strahan said. an atmospheric researcher from the Universities Space Research Association, who works at NASA Goddard. "If the warming had not occurred, we would probably consider a much more typical ozone hole."
Ozone is monitored by NASA and NOAA using various instruments, including satellites and weather balloons. The NOAA balloons carry "probes" with which the ozone layer can be measured.
"This year, ozone probe measurements at the South Pole did not reveal any areas of the atmosphere where ozone was completely degraded," said atmospheric researcher Bryan Johnson from the Earth System Research Laboratory at NOAA.
About 20 kilometers above the surface The temperatures were 29 degrees warmer and thus the warmest year since the beginning of the observations. In addition to minimizing ozone depletion, the weather systems responsible for the temperature shift reduced the Antarctic beam current from 161 mph to 67. This weakened the polar vortex and dropped it into the lower stratosphere.
Less clouds formed and ozone-rich air was brought over the ozone hole.
The Antarctic ozone layer is expected to recover by 2070 when compounds used as refrigerants, so-called chlorofluorocarbons, decrease. They were regulated 32 years ago by the Montreal Protocol.
According to NOAA, the ozone hole will disappear in the next six weeks and close.