The Hole in the Ozone Layer Over the Arctic has been closed

It was formed at the end of March 2020 and has begun to close on 20 April 2020. Previously also, in 2011, this type of strong chemical ozone depletion was observed during spring.

The Hole in the Ozone Layer Over the Arctic has been closed

From the last few decades, scientists are always worried about the damage to Earth's protective ozone layer. Therefore, they continuously monitor and observe their healing and depletion each year. This year, significant low values have been observed over the Arctic. The Copernicus Atmosphere Monitoring Service (CAMS) has confirmed that the largest ozone hole in the Arctic has closed due to atmospheric conditions (in an official tweet from Copernicus ECMWF). 

It was formed at the end of March 2020 and has begun to close on 20 April 2020. Previously also, in 2011, this type of strong chemical ozone depletion was observed during spring. When CAMS observed the unusual ozone hole over the Arctic this spring, it was found that the depletion is even stronger than in 2011. 

Now, scientists have confirmed the healing of this 1 million square kilometres wide hole. 

What were the observations from CAMS?

This year, it was found that the ozone layer over the Arctic has been depleted between 80-50 hPa. 

As observed on 29 March by CAMS, the total column ozone field was below 250 DU (Dobson units) over large parts of the Arctic.(Credit: CopernicusECMWF)

Temperature 

When we compare the Arctic stratosphere with the Antarctic, it is less isolated owing to landmasses and Mountain Ranges. They interfere with the weather patterns, which is less in the southern hemisphere. Therefore, the polar vortex in the Northern Hemisphere is not as strong as the Southern Hemisphere. However, in 2020 the Arctic polar vortex lived longer than expected. 

Since the starting of the year 2020, temperatures in Arctic Stratosphere were recorded low that resulted in the formation of PSCs. This was the reason for large ozone losses. 

(Credit: CopernicusECMWF)

Data sources

CAMS used the data assimilation process to combine information of its numerical atmospheric models, ground observations a d satellite data. It also took the help of ozone satellite observations from instruments like Sentinel-5P/TROPOMI, MLS, SBUV-2, GOME-2, and OMI. 

Observations from an instrument on NASA's Aura satellite, known as Microwave Limb Sounder, indicated that the depletion will slow down to an end because the active chlorine stock is exhausted. CAMS forecast already suggested that after the breaking of the polar vortex, ozone rich air of lower altitudes is going to mix with ozone depleted air. 

Scientists have also added that the reduced pollution due to COVID-19 lockdowns has nothing to do with the healing of the ozone layer in the Arctic. Most probably it is due to the high altitude currents that brought up the cold air to the polar regions.