NASA reveals new results from inside the ozone hole

Dec 11, 2013 by Kathryn Hansen
This is a cross-section of Earth's ozone layer as measured by the limb profiler, part of the Ozone Mapper Profiler Suite that's aboard the Suomi NPP satellite. Credit: NASA/NOAA

NASA scientists have revealed the inner workings of the ozone hole that forms annually over Antarctica and found that declining chlorine in the stratosphere has not yet caused a recovery of the ozone hole.

More than 20 years after the Montreal Protocol agreement limited human emissions of ozone-depleting substances, satellites have monitored the area of the annual and watched it essentially stabilize, ceasing to grow substantially larger. However, two new studies show that signs of recovery are not yet present, and that temperature and winds are still driving any annual changes in ozone hole size.

"Ozone holes with smaller areas and a larger total amount of ozone are not necessarily evidence of recovery attributable to the expected chlorine decline," said Susan Strahan of NASA's Goddard Space Flight Center in Greenbelt, Md. "That assumption is like trying to understand what's wrong with your car's engine without lifting the hood."

To find out what's been happening under the ozone hole's hood, Strahan and Natalya Kramarova, also of NASA Goddard, used satellite data to peer inside the hole. The research was presented Wednesday at the annual meeting of the American Geophysical Union in San Francisco.

Kramarova tackled the 2012 ozone hole, the second-smallest hole since the mid 1980s. To find out what caused the hole's diminutive area, she turned to data from the NASA-NOAA Suomi National Polar-orbiting Partnership satellite, and gained the first look inside the hole with the satellite's Ozone Mapper and Profiler Suite's Limb Profiler. Next, data were converted into a map that shows how the amount of ozone differed with altitude throughout the stratosphere in the center of the hole during the 2012 season, from September through November.

A look inside the 2012 ozone hole with the Ozone Mapper and Profiler Suite shows how the build-up of ozone (parts per million by volume) in the middle stratosphere masks the ozone loss in the lower stratosphere. Credit: NASA

The map revealed that the 2012 ozone hole was more complex than previously thought. Increases of ozone at upper altitudes in early October, carried there by winds, occurred above the in the .

"Our work shows that the classic metrics based on the total ozone values have limitations – they don't tell us the whole story," Kramarova said.

The classic metrics create the impression that the ozone hole has improved as a result of the Montreal protocol. In reality, meteorology was responsible for the increased ozone and resulting smaller hole, as ozone-depleting substances that year were still elevated. The study has been submitted to the journal of Atmospheric Chemistry and Physics.

Separate research led by Strahan tackled the holes of 2006 and 2011 – two of the largest and deepest holes in the past decade. Despite their similar area, however, Strahan shows that they became that way for very different reasons.

The area of the ozone hole, such as in October 2013 (above), is one way to view the ozone hole from year to year. However, the classic metrics have limitations. Credit: NASA/Ozone Hole Watch

Strahan used data from the NASA Aura satellite's Microwave Limb Sounder to track the amount of nitrous oxide, a tracer gas inversely related to the amount of ozone depleting chlorine. The researchers were surprised to find that the holes of 2006 and 2011 contained different amounts of ozone-depleting chlorine. Given that fact, how could the two holes be equally severe?

The researchers next used a model to simulate the chemistry and winds of the atmosphere. Then they re-ran the simulation with the ozone-destroying reactions turned off to understand the role that the winds played in bringing ozone to the Antarctic. Results showed that in 2011, there was less ozone destruction than in 2006 because the winds transported less ozone to the Antarctic – so there was less ozone to lose. This was a meteorological, not chemical effect. In contrast, wind blew more ozone to the Antarctic in 2006 and thus there was more ozone destruction. The research has been submitted to the journal Geophysical Research Letters.

This work shows that the severity of the ozone hole as measured by the classic total column measurements does not reveal the significant year-to-year variations in the two factors that control ozone: the winds that bring ozone to the Antarctic and the chemical loss due to chlorine.

Until chlorine levels in the lower stratosphere decline below the early 1990s level – expected sometime after 2015 but likely by 2030 – temperature and winds will continue to dictate the variable area of the hole in any given year. Not until after the mid 2030s will the decline stratospheric chlorine be the primary factor in the decline of ozone hole area.

"We are still in the period where small changes in chlorine do not affect the area of the ozone hole, which is why it's too soon to say the ozone hole is recovering," Strahan said. "We're going into a period of large variability and there will be bumps in the road before we can identify a clear recovery."

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shavera
3.9 / 5 (7) Dec 11, 2013
I think it's advisable to keep an eye on that second to last paragraph. We didn't put chlorine up there overnight, and we shouldn't expect it to come down overnight either. The processes of the Earth are slower than humans may like, and that means a lot of our goals are further in the future than the actions we take now. But it also means we have to think on generational scales and not on yearly ones.
NOM
4.3 / 5 (6) Dec 11, 2013
The history of the Montreal Protocol is interesting. There was a persistent and vocal minority of people who denied that there was any human effect on the ozone layer.
kehvan
1.8 / 5 (5) Dec 11, 2013
The history of the Montreal Protocol is interesting. There was a persistent and vocal minority of people who denied that there was any human effect on the ozone layer.


The ozone layer is created by UV radiation forcing molecular oxygen into the triatomic molecule of oxygen we call ozone. The fact is, many reasonable, intelligent and scientifically trained people were doubtful about all the fear surrounding the ozone hole, because the fact is the arctic and antarctic are regions of the planet shrouded in darkness 6 months out of the year. There was always going to be less ozone over of the poles of the planet.
StillWind
1.5 / 5 (8) Dec 12, 2013
@NOM, there is still a persistent and vocal group that denies that humans had anything to do with the so called "ozone hole". They happen to be the ones who actually understand a little something we call science.
There isn't the slightest evidence that CFC's caused destruction of ozone beyond the natural process that is caused by UV.
Moreover, there isn't even an attempt to describe how an insignificant amount of heavier than air gas is able to climb to those heights, while the vast amounts of surface produced ozone can't get there to replace what is destroyed.
Anyone with a brain knows that this was just another scam meant to stop the sales of a stable and effective refrigerant, so that is could be replaced by more costly and dangerous chemicals that don't work, and require massive retrofitting.
Thanks dumb masses.
katesisco
1 / 5 (3) Dec 12, 2013
Iodine from the ocean surface reinforces O3
Maggnus
3.2 / 5 (5) Dec 12, 2013
They happen to be the ones who actually understand a little something we call science.
Oh boy, here we go.
There isn't the slightest evidence that CFC's caused destruction of ozone beyond the natural process that is caused by UV.
Not even the slightest?
Moreover, there isn't even an attempt to describe how an insignificant amount of heavier than air gas is able to climb to those heights, while the vast amounts of surface produced ozone can't get there to replace what is destroyed.
Not even an attempt? Insignificant?
Anyone with a brain
Describe this "brain" thing you talk about.
knows that this was just another scam meant to stop the sales of a stable and effective refrigerant, so that is could be replaced by more costly and dangerous chemicals that don't work, and require massive retrofitting.
Thanks dumb masses.
Another scam? There's more than one? That there is some serious and mind-numbingly conspiracist denialism.
kehvan
2.3 / 5 (3) Dec 12, 2013
Maggnus, why not refute the man, instead of just offering snarky comments?
Maggnus
4.2 / 5 (5) Dec 12, 2013
Refute what kehvan? Refute that the only ones who understand science are the ones that deny humans had anything to do with the ozone hole? Refute that there isn't "even the slightest evidence" of CFC destruction of ozone? Refute that "there isn't even an attempt to describe" the workings of CFC's on the atmosphere? What bloody good does it do to argue with someone who puts that kind of garbage on an f'n science site? Do you understand what "denialism" is?
I will bloody well snark at such ignorance each and every time I see it.
Maggnus
4 / 5 (4) Dec 12, 2013
Oh, wait, I just realized that you are in that camp. No wonder you commented as you did.

All right, lets start with the first mistake you made, right off the hop.
The ozone layer is created by UV radiation forcing molecular oxygen into the triatomic molecule of oxygen we call ozone.
No, its not. The ozone layer is created when UV breaks up molecular oxygen, and the free oxygen atom combines with a "normal" oxygen molecule (O2) to form the larger molecule, ozone (O3).
The fact is, many reasonable, intelligent and scientifically trained people were doubtful about all the fear surrounding the ozone hole, because the fact is the arctic and antarctic are regions of the planet shrouded in darkness 6 months out of the year.
The fact is, many reasonable, intelligent and scientifically trained people also claim the Earth is only 6000 years old. This is the fallacy of appeal to a higher authority. cont....
Maggnus
4.2 / 5 (5) Dec 12, 2013
There was always going to be less ozone over of the poles of the planet.
Clearly, you do not understand what Brewer-Dobson circulation is. http://www.ccpo.o...6_3.htm.

How about you try learning about what you are trying to argue for, instead of making clearly uninformed comments about something you seem to know little about?
NOM
4 / 5 (5) Dec 12, 2013
Magnus, arguing with denialists is futile. I think their refusal to see the truth, despite indesputable evidence, is due to a mental disorder.
Maggnus
4 / 5 (5) Dec 12, 2013
Yea NOM, you're right. I just can't sit idly by while such stupidity is put on public display! :) ".....forcing molecular oxygen into the triatomic molecule..." And Jesus wept!
runrig
4.8 / 5 (4) Dec 13, 2013
Kehvan and StillWind

Epic fail my friends..

O3 is being continuously created and destroyed (equally) by UV in the stratosphere, making heat as a by product …. Which. I think you will find if twigged, means an absence of UV "when shrouded in darkness 6 months.." makes no overall difference to the total (normally).
However...
Chlorine like molecules (man-made) in the presence of extreme cold do continually destroy O3.

Both of you may learn something if you read at these links:
http://www.epa.go...ess.html

Dumb Asses indeed you are.
runrig
5 / 5 (4) Dec 13, 2013