Why the largest-ever Arctic ozone hole just closed
We've heard of this term before, but what is it actually? What causes this vortex to spread down south? Let's find out.
An ozone hole over the Arctic that was the largest ever recorded there has closed, according to the Copernicus Atmosphere Monitoring Service (CAMS). And its beginning and end have nothing to do with climate change, global warming or a reduction in air pollution because of the coronavirus pandemic.
It has to do simply with the weather.
CAMS monitored the rather unusual ozone hole that formed over the Arctic this spring and was reported closed April 23. Ozone holes are more common over the Antarctic every year, according to CAMS, but “the conditions needed for such strong ozone depletion are not normally found in the Northern Hemisphere.”
The Arctic stratosphere is usually less isolated than its Antarctic counterpart because the presence of nearby land masses and mountain ranges disturbs the weather patterns more than in the Southern Hemisphere, CAMS reports.
The total column ozone field (in Dobson Units) from CAMS on 29 March 2020 showing values below 250 DU over large parts of the Arctic. (Source: Copernicus Atmosphere Monitoring Service, ECMWF)
This year, however, a particularly strong polar vortex led to the Arctic ozone hole in which most of the ozone typically found around 11 miles into the stratosphere was depleted, according to CNN. The last time such a strong depletion was observed in the Arctic was almost a decade ago.
So, why did it occur this year?
“The behavior of the ozone and the stratospheric polar vortex during the winter into spring is supported by a couple of research papers,” said AccuWeather Senior Meteorologist Bob Smerbeck. “They state that the coldest and strongest polar vortex in the stratosphere and the lowest concentration of ozone over the Arctic are more likely to occur when you have a combination of a solar minimum, which we are in now, and a westerly QBO [quasi-biennial oscillation, meaning lower stratospheric westerly winds over the equator], which we had from last summer through most of this winter.
“These are all naturally occurring processes,” Smerbeck said.
A polar vortex that remained above the polar region without weakening and a strong positive phase of the Arctic Oscillation (AO) were among a combination of factors that led the contiguous U.S. to experience higher-than-normal temperatures from December 2019 through February 2020.
"When you have a strong polar vortex that remains in the polar region, it tends to keep frigid air pent up so that it is difficult for long-lasting outbreaks of frigid conditions to reach the middle latitudes, including portions of the Midwest and Northeast,” said AccuWeather Lead Long-Range Meteorologist Paul Pastelok.
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.Report a Typo
Grab your sweaters! November-like weather is on the way for the Midwest
Another batch of chilly air will suppress daytime highs and create AccuWeather RealFeel® Temperatures as low as the 20s, 30s and 40s for some.
Daily coronavirus briefing: Disney plans to lay off nearly one-quarter of its workforce
The Walt Disney Co. shut down parks as the pandemic worsened in the United States. Now the company is feeling the economic toll lockdown restrictions have taken on its businesses.
Have a cough? How to tell if it is fall allergies or the coronavirus
Experts offer up two key symptoms to be aware of that could help to differentiate between seasonal allergies and COVID-19.
Home air purifiers that can help filter out wildfire smoke
With air quality plummeting in some parts of the country, it's wise to have a device that can help clean the air you and your family breathe in your home.
Road trip emergency gear in case of bad weather
It's hard to predict when a road trip emergency might occur, but if you keep a few survival basics in your car you won’t have to worry about being unprepared.
AccuWeather School: Frost is not frozen dew
Frost forms under the same weather conditions as dew, except that temperatures have to be at or below freezing – so it makes sense that some people may think that frost is frozen dew, but that is not correct.