Although temperatures in the Antarctic stratosphere had created on average below average temperatures ideal conditions for the destruction of ozone in 2018, the decrease in the boreholes prevented the hole scientists NASA and the National Oceanic and Atmospheric Administration (NOAA) have shown that they were as big as 20 years ago.
The results showed that the ozone hole that forms in the upper atmosphere of the Antarctic each September is slightly larger than the average size in 201
"The colder temperatures this year would have given us a much larger one Ozone hole given when chlorine was still at a level we had seen in 2000, "said Paul A. Newman, chief scientist of Earth Science at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
According to NASA, the annual ozone hole in 2018 reached an average area coverage of 22.9 km².
NO AA scientists said the colder temperatures in 2018 allowed nearly complete removal of ozone in a deep, 5-km-long layer above the South Pole. In this layer, the active chemical degradation of ozone takes place in polar stratospheric clouds.
"Even under this year's optimal conditions, ozone loss at upper altitudes was lower, which we would expect in view of decreasing chlorine concentrations." See the stratosphere, "added NOAA scientist Bryan Johnson.
Nations of the world began using ozone-depleting substances in 1987 under an international treaty known as the Montreal Protocol.
The 2018 ozone hole was strongly influenced by a stable and cold Antarctic vortex – the stratospheric low pressure system that flows clockwise in the atmosphere above the Antarctic
Warming temperatures limited the formation of polar stratospheric clouds and slowed ozone hole growth in 2016 and 2017. In 2017, the ozone hole reached 19.7 km² in size before it began to recover.
Hole on 20.7 km ².
However, the current ozone hole is et compared to the 80s still big. when the ozone layer over the Antarctic was first detected. The atmospheric levels of man-made ozone-depleting substances increased until the year 2000.
Since then, they have slowly declined, but they remain high enough to produce significant ozone loss.