2014 Antarctic Ozone Hole Holds Steady

From NASA: The Antarctic ozone hole reached its annual peak size on Sept. 11, according to scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA). The size of this year’s hole was 24.1 million square kilometers (9.3 million square miles) — an area roughly the size of North America.

ozone_11sept2014[1]
This image shows ozone concentrations above Antarctica on Sept. 11, 2014.
Image Credit: NASA

The single-day maximum area was similar to that in 2013, which reached 24.0 million square kilometers (9.3 million square miles). The largest single-day ozone hole ever recorded by satellite was 29.9 million square kilometers (11.5 million square miles) on Sept. 9, 2000. Overall, the 2014 ozone hole is smaller than the large holes of the 1998–2006 period, and is comparable to 2010, 2012, and 2013.

With the increased atmospheric chlorine levels present since the 1980s, the Antarctic ozone hole forms and expands during the Southern Hemisphere spring (August and September). The ozone layer helps shield life on Earth from potentially harmful ultraviolet radiation that can cause skin cancer and damage plants.

The Montreal Protocol agreement beginning in 1987 regulated ozone depleting substances, such as chlorine-containing chlorofluorocarbons and bromine-containing halons. The 2014 level of these substances over Antarctica has declined about 9 percent below the record maximum in 2000.

“Year-to-year weather variability significantly impacts Antarctica ozone because warmer stratospheric temperatures can reduce ozone depletion,” said Paul A. Newman, chief scientist for atmospheres at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The ozone hole area is smaller than what we saw in the late-1990s and early 2000s, and we know that chlorine levels are decreasing. However, we are still uncertain about whether a long-term Antarctic stratospheric temperature warming might be reducing this ozone depletion.”

Scientists are working to determine if the ozone hole trend over the last decade is a result of temperature increases or chorine declines. An increase of stratospheric temperature over Antarctica would decrease the ozone hole’s area. Satellite and ground-based measurements show that chlorine levels are declining, but stratospheric temperature analyses in that region are less reliable for determining long-term trends.

Scientists also found that the minimum thickness of ozone layer this year was recorded at 114 Dobson units on Sept. 30, compared to 250-350 Dobson units during the 1960s. Over the last 50 years satellite and ground-based records over Antarctica show ozone column amounts ranging from 100 to 400 Dobson units, which translates to about 1 millimeter (1/25 inch) to 5 millimeters (1/6 inch) of ozone in a layer if all of the ozone were brought down to the surface.

ozone concentrations on 30 Sept. 2014
This image shows ozone concentrations above Antarctica on Sept. 30, 2014.
Image Credit:
NASA

The ozone data come from the Dutch-Finnish Ozone Monitoring Instrument on NASA’s Aura satellite and the Ozone Monitoring and Profiler Suite instrument on the NASA-NOAA Suomi National Polar-orbiting Partnership satellite. NOAA measurements at South Pole station monitor the ozone layer above that location by means of Dobson spectrophotometer and regular ozone-sonde balloon launches that record the thickness of the ozone layer and its vertical distribution. Chlorine amounts are estimated using NOAA and NASA ground measurements and observations from the Microwave Limb Sounder aboard NASA’s Aura satellite.

NASA and NOAA are mandated under the Clean Air Act to monitor ozone-depleting gases and stratospheric depletion of ozone. Scientists from NASA and NOAA have been monitoring the ozone layer and the concentrations of ozone-depleting substances and their breakdown products from the ground and with a variety of instruments on satellites and balloons since the 1970s. These observations allow us to provide a continuous long-term record to track the long-term and year-to-year evolution of ozone amounts.

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130 thoughts on “2014 Antarctic Ozone Hole Holds Steady

  1. No it is a thinning of concentration. They obviously didn’t find a warming in the upper atmosphere or they would have stated so

    • Yes, I am confused as well. According to warmist/alarmist “weather underground” site: “However, this recovery of the ozone layer is being delayed. A significant portion of the observed stratospheric cooling is also due to human-emitted greenhouse gases like carbon dioxide and methane. Climate models predict that if greenhouse gases are to blame for heating at the surface, compensating cooling must occur in the upper atmosphere.”
      So, if Antarctica’s stratosphere is warming, all the while well-mixed, human emitted greenhouse gases are cooling the stratosphere elsewhere, what gives?

  2. Since the record began only in the 70s, there’s insufficient data to conclude that the increase and decrease in the size of the ozone “hole” is unnatural. Who’s to say there hasn’t always been a “hole” and that its size hasn’t always varied dependent on the strength of the austral polar vortex?

    • I fully agree, Katherine, it’s the most basic of questions to ask in the first instance, & to date, nobody has provided an adequate answer, other than to rely on the bloodsucking lawyers (nothing personal you’re just understandably keeping the pay cheques flowing) imposition of the Precautionary Principle!

      • I strongly object to the description: “bloodsucking lawyers.”
        The profession is a fine, upstanding one… it’s just the 99% that give it a bad name.

      • FYI, the expression “bloodsucking lawyer” arose from the movie Jurassic Park, when John Hammond said that the only one on his side was the “bloodsucking lawyer!”. He did meet his just deserts at the teeth of the T-Rex, though! Tim, you are naughty! 😉

    • In fact, Katherine, the hole is completely natural. It is a complex reaction depending on the extreme cold of the polar winter and the naturally occurring atm. trace compounds.
      Chlorinated hydrocarbon compounds occur naturally, and naturally occurring bromine compounds are also thought to contribute in this process. The “hole” opens at the end of August and closes at the end of October as stratospheric circulation is restored above the Arctic. This process has likely been an annual occurrence since Antarctica occupied its polar position over 30 million years ago.

      • made Enron and others a shitload of money selling ozone trades..
        just like the CCeX did for goracle
        the first of the emperorsinvisible clothes scams

      • Many things about the poles are unique (magnetic field, temperature range, incoming solar radiation, etc.), it should not be a surprise that the atmosphere is a bit different as well.

    • Katherine, there has always be a ‘hole’ (thinning).

      Abstract – 15 August 2005
      Dominic A. Hodgson et al.
      Late Pleistocene record of elevated UV radiation in an Antarctic lake
      ………Here we show that mean exposure of these benthic cyanobacteria to UVR during the last glacial was more than three times higher than during the Holocene, likely due to short periods of photosynthetic activity coinciding with relatively high UVR fluxes, or due to increased UVR transmission to the Earth’s surface resulting from changes in external factors such as stratospheric ozone levels, cloud cover and surface albedo.
      http://www.sciencedirect.com/science/article/pii/S0012821X05003365
      ===========
      2002
      Paleoclimate: Toward solving the UV puzzle
      Rozema, Jelte et al
      https://lup.lub.lu.se/search/publication/131302
      https://lup.lub.lu.se/record/131302/file/624193.pdf

      • From NOAA, “In 1958, measurements of total ozone were made at the Dumont d’Urville station (66.7°S, 140°E) in Antarctica using a photographic plate method to analyze solar ultraviolet radiation after it passed through the ozone layer. The reported measurements were anomalously low, reaching 110-120 DU in September and October. These values are similar to minimum ozone hole values now routinely observed over Antarctica in the same months (see Figure Q11-2 in Q11: How severe is the depletion of the Antarctic ozone layer? PDF file). Some have speculated that these limited observations provide evidence that an ozone hole existed before ODS emissions were large enough to cause the depletion. However, analyses of the more extensive Dobson spectrophotometer measurements made at several other Antarctic locations in 1958 did not confirm the low total ozone values. These measurements indicate that the photographic plate determinations were not a reliable source of total ozone values at the Dumont d’Urville station in 1958.”
        I would say you have some disagreement about a “hole” it is also useful to know that the measurements the other stations were getting are not generally published but stated to be around 300, still looking for more exact information. The variability for this area is also very large (overall range over 200du) and susceptible to cherry picking. If the above stated measurement was accurate and there is really no reason to believe that it wasn’t other than its inconvenience to settled science, then there is a lot more to learn about this area.

      • David Riser:
        Do you hate the dates for all of those measurements? Because any taken before the beginning of Sept. or after November would have shown no ozone depletion.

      • MPainter,
        Yes, I believe that is why getting actual dates and numbers for those “other” measurements is virtually impossible.

    • It doesn’t matter if they say increase or decrease.
      It doesn’t matter if climate gets warmer or colder or stays the same.
      It doesn’t matter whether hurricanes or storms increase or decrease.
      Likewise for sea level.
      Likewise for the ozone “hole”.
      Modern politicized climate science uses a different strategy – simply to create a mood music to provide an atmosphere of menace to award themselves political power.
      Its enough just to mention words within a stream of text such as “climate” – “extreme weather” – “ozone hole” – “ocean acidification” – “sea level rise acceleration” etc. etc.
      The actual data relating to any of these is totally irrelevant. It is enough just to mention these charm words like a mantra to obtain the desired mesmerizing effect on a politically important audience.

      • You’re actually more cynical than I am that’s saying a lot. Those “issues” you mention are all big, natural, complex and mostly chaotic systems with cycles from yearly to millennial time frames with very little accurate historic data which are not yet fully understood.
        This means that somebody can take some data on any one of these systems and tell a story that cannot (currently) be disproved. And even if it’s a tall tale, if you get enough support and “authority” and money behind it, it can turn into a nice big shiny hammer. There, how’s that for cynical?

      • phlogiston,
        You might want to throw in a few “koch brothers”, “big oil money”, “paid by fossil fuel industry” as a Tourette’s style reflex whenever there is any objection raised or real data offered.

    • IIRC, the ban was on new production and not existing stockpiles, and existing stockpiles were enough to satisfy demand for some time to come. Open to being corrected on either point.

      • The absurd extremity of the ban is shown by the fact that Primatine Mist , the most effective , affordable , over the counter asthma inhaler has been banned , and even inventories impounded because of the couple of grams of CFC propellent used . This is one of the most criminal acts of the EPA and is certain to have killed some asthmatics .

  3. “The ozone layer helps shield life on Earth from potentially harmful ultraviolet radiation …”
    What UV ? What life ?
    The “holes” only happen over the poles , particularly the south , during their sunless winters . Dixy Lee Ray pointed out years ago that O3 is created by the dissociation of O2 by UV and has a certain half-life . The depletions form because there is no UV to generate more during the polar winters . They always have formed and always will . They will never occur over the sunlit portion of the globe , nor does it matter because the O2 will absorb the UV and create O3 even if the O3’s half-life is decreased by Cl .

    • I think you are right! Ozone is generated by UV, and this is the reason, why UV is shielded from earth surface; its energy is razed when it interacts with O_2, and the generating of O_3 is only a side product of this process.
      For example, the Ozone’s density is lowest over the equator, since the uprising winds shift the ‘ozone clouds’ to the higher and lower latitudes. But growth of plants and animals seems not to be hindered there very much. Instead of measuring ozone holes they should measure UV-light directly, but that wouldn’t yield much catastrophic results.

    • I thought they’d found other “thinnings” as opposed to “holes” in other parts of the world, or am I mistaken on this?

    • That is only half of the Chapman cycle. The other half has O3 being split back into O2 and O, as well as combining with O to form 2O2. A balance is achieved based on the natural rates of conversion. If you alter those rates of conversion, you change the balance. That is putatively the cause of the “hole”.
      Like the AGW hypothesis, it is a reasonable extrapolation of the basic physics and chemistry, but like the AGW hypothesis, the actual result does not necessarily adhere to the basic model when all influences are taken into account.
      It is just less important, because there are ready substitutes for CFCs, whereas CO2 generation cannot be eliminated from industrial civilization.

    • You have this completely wrong, the ‘holes’ are formed in the spring due to UV, when the sun rises over the pole, not in the winter .

      • Phil , I believe you are wrong . The article begins “The Antarctic ozone hole reached its annual peak size on Sept. 11” , just shortly before equinox , not that it suddenly forms for a short time just before sunlight returns full force . If it’s due to UV , why isn’t the O3 reduced over the entire sun lit globe ?
        Certainly the Chapman cycle cited by Bart almost assures that the decreased concentration will happen in the absence of UV and David Riser , who seems most knowledgeable about this here , says that the “slow” Wikipedia refers to is about 3 months .
        The time course of the formation of the “hole” thru the winter would resolve the issue .
        If Wikipedia is right that the decay is “slow” because of sparsity of atomic O , then presence of catalysts won’t make much difference .
        I recommend “Environmental Overkill: Whatever Happened to Common Sense?” , 1993 , by Dixie Lee Ray in general , and her chapter on this hole scare in particular . She was a very interesting woman , and if only the EPA could be run by someone like her today , all this nonscience would quickly be history .

      • The “hole” peaks in size in the Southern hemisphere Spring, suggesting the lagged impact of low UV Winter, in the same way daily temperatures tend to peak a couple of hours after high noon. If Summer high UV were the culprit, the hole should peak in size in late Summer to early Fall. Bob appears to have the right of it.

      • To clarify, if the hole reaches its minimum in Spring, then it must have been declining through low UV Winter. Conversely, it must be growing in high UV Summer.

  4. The ozone layer plays a huge role. Captures a huge part of ionizing radiation. May locally become warm, which causes waves
    altitude and pressure changes in the troposphere. The temperature gradient in the stratosphere constitutes drive for the polar vortex. Although ozone is so little, we owe him so much.

  5. Wonderful that the hole is maintaining itself in the face of such onslaught by IPCC and NASA amongst the villains who desperately plan and advertise its death from a particular year to year.
    Ha ha.
    Al Gore must be gnashing teeth, pounding fists on his 13th century teak-wood desk and throwing French Louie-XIV chairs out his office windows in San Jose.
    Snark snark

  6. Does Ozone get destroyed in these hole-making events?
    No. It just moves to the 40S to 60S latitudes which then has the highest concentrationon Earth at the time these holes develop. When the Solar radiation returns in mid-September, the stratosphere warms up, the circulation patterns change, and the Ozone moves back to the south polar region.
    That is a different pattern than if CFCs were actually destroying the Ozone molecules. They are not gone, they just move.

  7. It is a BIG problem that so little is known about the ozone hole prior to the use of those chemical being fingered as a problem. They can’t even say if there is, or ever has been, any man-made chemicals
    involved in a significant fashion. They are faced with the dilemma of natural experiments : the inability to control (or even identify) the various possible independent variables, in this case air temps and chlorine concentrations (plus probably others of which they are unaware). All they can do is observe the correlations and hope that the two independent variable of concern experience significant variations. At this point, though, all this seems to have become a rather moot or academic exercize – it’s appears obvious the ozone hole isn’t about to cause great harm.

  8. Climate ‘scientists’ call anything under 220 Dobson units a ‘hole’. Sounds scarier that way, and likely gets them more grant funding.
    But it happens every year during Antarctic winter, and then resolves every year during Antarctic summer when it gets back up in the 400s.
    A natural phenomenon related to the lack of solar UV in winter months . Nothing more.

    • sagi, but it happens in the antarctic spring- not winter- so how does the lack of solar UV make this a natural phenomenon? I’m fascinated with this discussion- find it entirely possible it’s natural – but just want to understand it correctly. Thanks!

      • I searched all over for a graph like that. Thanks.
        Very curious.Doesn’t really seem to track UV levels, or at least, what I’d expect UV levels to be (a smooth cycle, peaking in December, minimum in June). This seems almost entirely a springtime phenomenon. That seems to suggest potentially a biological connection.

      • Yup Bart, there is a blooming of biological life in the stratosphere in Springtime over Antarctica. High pollen counts and blooming flowers !!!

      • Bart , I think the rapid rise when the sun returns is strong evidence , along with the understanding of the underlying physics , that It is the UV which quickly restores the O3 to a saturated level . I would not have expected anything like a sinusoid but more like a plateau thru the summer starting to decay as early as April .

      • juan @ November 1, 2014 at 12:06 pm
        What a dumb comment. The very idea of human produced CFCs affecting the ozone layer is that surface inputs get lofted to higher altitudes. See here, for example.

        The halogens chlorine, bromine and iodine belong to the class of ozone-depleting substances. Water plants like seaweed, macroalgae and microorganisms called phytoplankton form natural halogenates and release them into the air. “In the tropical West Pacific we expect to find particularly rich sources of these trace gases,” says Prof. Dr. Klaus Pfeilsticker of Heidelberg University’s Institute of Environmental Physics, the overall coordinator of the interdisciplinary research project. “During the rainy season there, we also have the main transport of ground-near air masses into the stratosphere, where the ozone layer is located.” So far the role of these natural halogenated hydrocarbons in ozone depletion is unclear. “The SHIVA project is designed to find out what damage they can inflict on the ozone layer in a changing climate,” says Prof. Pfeilsticker.

      • But, Bob, it doesn’t even start to decline until months after the minimal UV level is attained. I could see an accelerating decline, but it really is quite steady until it falls off the cliff at the beginning of Spring.

      • Yes Bart, we all know Antarctica is teeming with “Water plants like seaweed, macroalgae and microorganisms called phytoplankton” all over the ice. Satellite photographs of these plants are easily spotted with their obvious WHITE color on the Antarctica peninsula.
        Springtime in Antarctica is lovely. I’m glad you were able to determine that the biological life in the Antarctic springtime is a significant contributor to the ozone depletion.

      • It you take out the big dip, it appears there may be a somewhat sinusoidal low level variation of ~ +/- 20 DU, which I would bet was the UV dependence. For the dip itself, I think I’d like to see where Dr. Pfeilsticker goes with his research.

      • @Bart

        Look up a word called “perihelion”

        It is a much better explanation than “a biological connection.”

        Why?

        Because the water plants in the topical pacific emitting their natural halogenates can’t tell the difference between May and September.

      • I apologize to you Mr Bart.

        I’m sorry I made your suggestion of a “biological connection” look ludicrous

      • OK, you’ve convinced me. There is no difference between Winter and Spring in the Southern Hemisphere. Now, will you go away?

      • Bart , the graph presented by sagi definitely shows the decline beginning in mid August . MidWinter is about August 4 . ( I know because I used to hold MidWinter parties when I lived in NYC ; I hold MidSummer ones since moving to 2500 meters up in the CO front range . ) It clearly reaches is minimum in early October about the second week of spring .
        If you don’t think its linked to the obvious seasonal variable , UV , what do you think it’s linked to ?

      • The equinox is Sept. 22. The solstice is June 21. The cliff’s edge is mean mid-August, about 2 months after the solstice, and 1 month before the equinox. UV has been down a good long time before the cliff. But, this is the time that biological activity starts to build rapidly in anticipation of Spring.
        I’m not saying it is definitely biological activity, merely that it is portentous, given the sudden onset of the decline at that time. But, the fact that UV started declining and reached its nadir months earlier tells me it isn’t likely the level of UV that is driving it.

  9. The ozone hole surrounds the magnetospheric footprint. It is modulated by the action of the magnetosphere…

    • Actually , I am surprised that the decline is distinctly not exponential . Look like it doesn’t take off until a little before mid winter . Still , it clearly returns to “normal” rapidly after the sun returns .
      It seems to be far more closely centered on the rotational pole than the magnetic pole , and , again , I’ve never heard of any seasonality in the magnetosphere . Is there some ?

  10. 1) Yes, UV dissociates O2 into atomic oxygen, which then combines with O2 to form O3. But that’s not the whole story. Not all the UV spectrum is absorbed by oxygen dissociation. The O3 actually does absorb the remaining UV spectrum, so it’s not a meaningless byproduct.
    2) Who really knows if man-made halocarbons are any kind of culprit? It turns out that there is a layer of sodium ions in the upper atmosphere. This layer is useful for the creation of a laser “guidestar” effect that is used with astronomical telescopes equipped with active deformable optical elements, to correct for atmospheric optical aberrations. Atmospheric mixing (oceanic storms) can bring salty water into the upper atmosphere. The water evaporates and the salt (sodium chloride) is split by UV into atomic sodium and atomic chlorine. We know both the sodium and the chlorine are up there. There is no way in the world that this mechanism can be influenced by human activities.
    3) Due to the wavelength dependency of Rayleigh scattering (inversely proportional to the 4th power of the wavelength, which is why the sky is blue), 50% of all UV gets scattered into space, ozone hole or no. (UV does not travel in straight lines in normal atmosphere. It is like light diffusing through a thick fog.)
    4) There are significant high-altitude electrical discharge phenomena observed over thunderstorms. It is expected that these discharges would produce ozone. Anybody have a verifiable budget of ozone sources and sinks that includes this phenomenon? Or do we just disregard it because it couldn’t possibly be important?
    To paraphrase an old joke: “It’s assumptions, all the way down.”

    • The level of inorganic Cl above 10km is less than 0.04 ppbv, whereas organic Cl from CFCs etc is ~4 ppbv so your assumption that it’s NaCl that’s the problem is wrong.

      • Do the chlorine ions carry cards that tell whether they are organic or not? Or are you comparing chlorine in organic molecules with free chlorine ions which are two very different things.

      • The only thing that counts is atomic chlorine, having been separated from its source molecule by UV radiation. As someone else pointed out with wit, chlorine atoms do not carry “organic” or “inorganic” tags. The atomic chlorine combines with atmospheric oxygen to form the reactive radicals that catalyze ozone breakdown.
        I made no ASSUMPTION. I posed a POSSIBILITY. And you haven’t shown any argument to dismiss it. In either case, it comes down to an estimate of tons of atomic chlorine produced annually by available mechanisms, be they halocarbon dissociation from UV or saline dissociation from UV. Let us suppose that there is at one atom of chlorine for every atom of high-altitude sodium. What are these numbers? Inquiring minds want to know.
        Do you also have an inventory of all ozone sources? That was a QUESTION I asked. We should know by now that keeping track of the ins and outs is essential to understanding any problem of equilibrium.

    • Very interesting . Particularly that the Rayleigh scattering is that strong .
      Do you have the actual spectra ? The atmosphere is shown as quite opaque in the UV . Are the oxygen lines the only absorbers ?
      I’m really just an APL programmer who got sucked into this because of the pervasive non-quantitative amateurish math and physics I saw . I take it the layer where the UV is absorbed creates the thermosphere .

      • There are UV communication systems that have been designed and made operational for short-range communication around obstacles that would otherwise prevent line-of-sight communication.
        We also get sunburned, so that is personal evidence that the UV is not entirely blocked by the atmospheric absorption and scattering.

  11. It’s obvious the “ozone hole” is some left wing conspiracy designed to deprive us of our CFCs and thus create a new world order. First they came for our DDT, then our CFCs…

  12. So first off the reason for Ozone Hole maximum in September is because the half life of ozone in the lower stratosphere (temp in the -50c range) is 3 months. So once the UV radiation ceases to make ozone it takes a lag of 3 months to see a maximum reduction. So the reaction is somewhat complex but it primarily depends on UV to hit O2 to create O3. While O3 also absorbs UV. So UV makes ozone and ozone absorbs more UV. So the idea that the earth would ever run out of ozone in the stratosphere is a little bit ridiculous. If the temp goes up the natural breakdown rate of ozone goes up but because the temp in the stratosphere is very stable a few degrees here or there is not going to have much impact. More CO2 would actually, according to theory, reduce the stratosphere’s temp we haven’t’ actually gotten enough data to make that connection one way or the other. Satellite data started in 1978 and has had a few holes in the data caused by nonfunctioning craft. So give the record another 30+ years and we may actually start to see what the natural pattern is. While measuring devices for ozone have existed since the 20’s there are only a few places where there is a long term record. In the 50’s we started setting up research stations in the Antarctic but those were never manned during the winter half of the year in Antarctica. Additionally Antarctica has a rather unique atmospheric weather system that is not understood well within climate science. So a lot of questions remain, the science in Antarctica is very unsettled!

    • Maybe. I do not have a definite opinion as of yet. However, the release of highly reactive compounds appears to me to have more likely adverse effects than the release of fairly benign CO2, the only significant effect of which should be beneficial, i.e., stimulation of plant growth.
      In any case, it definitely was a catalyzing event, in that it marked a major milestone along the path to the Green Religion, whose fanatical followers plague us now.

  13. Bart November 1, 2014 at 12:02 pm
    I searched all over for a graph like that. Thanks.
    Very curious.Doesn’t really seem to track UV levels, or at least, what I’d expect UV levels to be (a smooth cycle, peaking in December, minimum in June). This seems almost entirely a springtime phenomenon. That seems to suggest potentially a biological connection.

    It is a springtime phenomenon as I pointed out above, it’s due to the release of compounds that are catalytic in the destruction of O3 being released as the incoming sun causes the sublimation of the PSCs.

    • Be nice if you could leave a link at the discussion telling me you are carrying it on elsewhere.
      This sounds potentially reasonable to me, given the discussion from which you quoted me. But, you left out the detail with a passive voice. “Being released” by what or whom? Human CFC inputs, in the absence of contrary information, I would assume would be a year-round phenomenon. So, it would appear that the sudden appearance of the “hole” itself largely is a natural phenomenon.

      • There was no reply link so I continued at the bottom.
        The effect of the Polar Stratospheric Clouds, which are formed in the extremely cold conditions of the polar vortex of the antarctic winter from nitric acid, is to increase the rate of the reactions which form Cl2 gas. In the absence of UV light the Cl2 accumulates, once the spring time UV appears then Cl radicals are formed by photolysis. These radicals initiate the catalytic cycle which destroys the O3. As the warmup continues the PSCs sublimate and the enhanced production of Cl2 stops as does the isolation by the vortex.

      • OK, this would tend to explain why the onset of the dip is in Spring, and why the effect peters out as Spring progresses. Thank you.
        I guess the remaining question for me is, how much of this is due to human generated halogens, and how much due to naturally occuring halogens? And, then there is the question of how well the entire process is understood.
        http://arstechnica.com/science/2007/10/ozone-chemistry-confounds-everyone/
        http://www.sciencedaily.com/releases/2007/07/070726104756.htm
        http://www.nature.com/nature/journal/v449/n7161/full/449382a.html
        As I said above, I am not a confirmed skeptic on this issue, merely wary of a rush to judgment. It is reasonable to me that highly reactive compounds like CFCs being released into the atmosphere could have deleterious effects.
        The decline in atmospheric column Cl equivalent since the early 90’s is certainly suggestive that the ban was a good idea. I wish we had a longer record to observe. But, I believe the weight of the evidence is high enough to establish that the CFC ban was a reasonable, precautionary measure.

    • Phil ,
      I’ll agree it’s a spring time thing rather than quibble that it’s a MidWinter to MidSpring thing because I’ve long felt it’s the seasons which are labeled wrong . Summer should be the quarter of the year with
      the greatest insolation , winter with the least , and spring and fall – the transitions . I think there’s an adjective some field uses to denote those .
      Here are the daylight maps for around the beginning ,  August 15 ,

      middle , October 4 ,

      and end , December 15 , a little before the summer solstice :

      It’s an odd phenomenon and clearly not just a simple exponential decay and recovery , but tightly coupled to the solar season .  Sagi’s post from http://www.sciencedaily.com/releases/2011/10/111020145106.htm , shows it is quite robust and has not changed since 1986 . I think clearly minor variations in CFCs have nothing to do with it .

    • Thanks for the extended explanation of what PSCs are . It’s a compelling story as long as all the pieces are observable . To produce such a sharp drop and restoration so tightly linked to the end of winter requires something like this sort of spring thaw . Do you have any link to a more complete reference ?
      This discussion , and especially seeing the regular V shaped springtime graph has convinced me that the notion that CFCs have anything to do with “the hole” is as absurd as the idea that the planet’s temperature is critically dependent on a couple of well saturated absorption lines of the molecule without which none of us would be here .
      And for this fraud , asthmatics can no longer get effective inexpensive non-prescription inhalers .

      • But Phil , I think both the extremity of the dip, with or without your explanation , and the fact that it was there the first time anybody looked , shows that it is natural and permanent .
        The issue of concern over CFCs is what spectral window do they open up in the sunlit portion of the globe . Is there any band that they make transparent all the way to the surface ?
        BTW , being a kid science nerd , I remember all the hoopla leading up to the “International Geophysical Year” when all this antarctic research got kick started and the “hole” was first observed . I think David Riser comments about it being inconvenient to “settled science” carries weight .
        I’ll withdraw the use of “fraud” , but continue to claim lack of common sense in banning the use of a couple of CCs of propellants in asthma inhalers . Apparently the manufacturers of Primatene were not able to find a suitable substitute and just stopped production .
        This issue is pretty far afield from my interests ( which is more about array programming language notation and implementation ) and clearly gets into more detail than I have time for . My main issue in all of this is just getting the computations of planetary temperature clearly understandable in succinct APL , and taking down Hansen’s quantitative absurdity that Venus can be explained as a “runaway greenhouse” .

      • The graph I presented earlier shows that solar UV is likely the determinant of cyclic Antarctic ozone levels.
        So if existing atmospheric CFCs have any additional effect, how might that graph look, in theory, without any of those CFCs present?
        Or, asking the question another way, is there any theoretical CFC effect that solar UV cannot easily overcome when spring returns to the Southern Hemisphere every year?
        And would that cyclic dip related in part to the half life of ozone really look any different?

  14. tty November 2, 2014 at 2:58 am
    Do the chlorine ions carry cards that tell whether they are organic or not? Or are you comparing chlorine in organic molecules with free chlorine ions which are two very different things.

    What chloride ions? Organic chloride is covalently bound in such molecules as CFCs, methyl chloride etc., ‘inorganic chloride’ is primarily HCl, the principle source of which is acidification of sea salt, at sea level this ranges from 0.05-0.5ppbv. However it’s extremely soluble in water and condensation effectively removes it from the upper troposphere, down to ~0.1ppbv at 7km and ~0.04ppbv at 14km.
    UV photolysis of the organic chloride compounds in the stratosphere generates Cl atoms (not ions) which are catalytically destructive of ozone.

    • I don’t like your argumentative method. He understood what was going on and you are bashing him over the head with something he never argued. The issue is the generation of free single chlorine atoms from photolysis of EITHER halocarbons OR chlorides (NaCl will split nicely in the presence of UV, I’ve checked the numbers. You don’t need to make hydrogen chloride.). The point is that once you get an atom of chlorine, you can’t deduce where it came from.
      By the way, clouds (water vapor, possibly including saline water if they are thunderstorms) top out at the tropopause, which is approximately at 30,000 feet, and constitutes the beginning of the stratosphere. UV is strong enough at that altitude to have effects.

      • Hear, hear.
        And if the ozone layer does decline then surely the altitude at which UV is ‘strong enough’ would become lower too.
        However, I also suspect that saline from saltwater droplets is by far the dominant factor due to abundance. (Can’t prove that but it seems logical).

  15. Bob Armstrong November 3, 2014 at 8:11 am
    But Phil , I think both the extremity of the dip, with or without your explanation , and the fact that it was there the first time anybody looked , shows that it is natural and permanent .

    Just because something is extreme doesn’t mean it’s natural.
    Also it is not a ‘fact’ that it was there the first time anyone looked.
    While there was a seasonal cycle in Ozone when Dobson et al first started monitoring it and the annual cycle in O3 at the antarctic was larger than elsewhere, the spring minimum was around 300 DU in the late 50s and early 60s. The rapid drop as a result of CFC accumulation (see above) started in the late 70s, since which time the CFC levels have doubled).
    http://ozonewatch.gsfc.nasa.gov/facts/images/halley_toms_ozone.png
    Instruments on the ground (at Halley) and high above Antarctica (the Total Ozone Mapping Spectrometer [TOMS] and Ozone Monitoring Instrument [OMI]) measured an acute drop in total atmospheric ozone during October in the early and middle 1980s.
    The natural cycle involving a reduction of O3 due to the naturally occurring Cl in the stratosphere has been greatly enhanced by the much greater levels of Cl caused in particular by the accumulation of the persistent CFCs in the atmosphere.

    • Ok . That’s pretty convincing . I think it’s quite useful to have brought all this info into one place .
      However , in practical terms , does it make any practical difference over the inhabited world ? Do you have spectra for the O2 and O3 absorption bands ? I assume atomic O has no relevant absorption .
      I would think over the well-lit world , O3 would be regenerated until there was no more light left in the O2 lines to dissociate any more O2 .

    • “The natural cycle involving a reduction of O3 due to the naturally occurring Cl in the stratosphere has been greatly enhanced by the much greater levels of Cl caused in particular by the accumulation of the persistent CFCs in the atmosphere.”
      Maybe. This is still an active area of research. See links provided above.

      • One of the two papers which critiqued the Pope et al. work was:
        Chen, H. Y., C. Y. Lien, W. Y. Lin, Y. T. Lee, and J. J. Lin (2009), UV absorption cross sections of ClOOCl are consistent with ozone degradation models, Science, 324(5928), 781–784.
        Which used a very elegant method quite different from Pope and showed where the probable error in Pope’s method lay.
        Recently Pope et al. have revised their method and come up with a new result which is in agreement with other data, their earlier work was very much an outlier.
        http://pure-oai.bham.ac.uk/ws/files/15006004/grl51389.pdf
        Their conclusion was:
        “The photolysis of chlorine peroxide (ClOOCl) is a key chemical step in the depletion of polar stratospheric ozone. This study provides an optically pure ClOOCl spectrum in the photolytically important UV wavelength region (200–350 nm) that is in good agreement with other recently published spectra. Second, the study provides the first ever measurement of the ClOOCl spectrum in the visible region (509–536 nm) conclusively demonstrating the photolysis of ClOOCl to be negligible in this spectral region. The visible measurement can be used to anchor other previously recorded UV spectra and hence reduce the uncertainty in ClOOCl photolysis rate calculations. The calculated photolysis rate from this study indicates that current models of stratospheric ozone depletion are correct. Furthermore, the new visible spectrum measurement greatly improves the confidence in this result.”

      • All right, I’ll give you “probably”. You have to admit, the case is a lot stronger than the case for CO2 induced anthropogenic global warming.

    • Interesting.
      What were the levels of Antarctic O3 during the rest of the months in the 1960s?
      Were they similar to current values in the sunlit months? In other words, does ozone ‘max out’ in the summer, regardless?

      • That is what I understand Phil to have stated. The creation of the hole is fueled by the presence of PSCs (polar stratospheric clouds) which build over the winter, and then burn off in the Spring.

      • The basic Chapman mechanism leads to a small decline worldwide (~4%/decade IIRC), the surprise was the enhanced decline in the Antarctic and sometimes in the Arctic. This turned out to be due to the heterogeneous reaction on the PSCs which wasn’t expected.

  16. sagi November 3, 2014 at 8:39 am
    The graph I presented earlier shows that solar UV is likely the determinant of cyclic Antarctic ozone levels.
    So if existing atmospheric CFCs have any additional effect, how might that graph look, in theory, without any of those CFCs present?

    The graph below shows the ozonesonde October data from 1967-80 before any significant O3 depletion (CFC below 100pptv) solid black line compared with the data from October 1992 when CFC was about the max of 275 pptv. Note the almost total destruction of O3 between 12 and 20 km where formerly it was at the maximum. So without CFCs that peak would still be there.
    http://www.esrl.noaa.gov/gmd/ozwv/dobson/papers/wmobro/graphics/fig8m.gif
    As far as seasonal variation is concerned the drop from pre-CFC times (1957-78) during the summer is about 10% whereas in the spring jot is much greater, ~50%.
    http://www.esrl.noaa.gov/gmd/ozwv/dobson/papers/wmobro/graphics/fig9m.gif
    Regarding the inhabited world the following graph shows the decline over Germany:
    http://www.esrl.noaa.gov/gmd/ozwv/dobson/papers/wmobro/graphics/fig15m.gif

    • Thanks for the additional info .
      I dislike “delta” graphs like that last one because they magnify whatever is being plotted until it fills the graph . It’s a real problem in the main AGW arena where far too few realize the total variation in temperature that the whole brouhaha is over is about 0.3% associated with a greater than 33% change in CO2 . What is true 0.0 on that nb scale ( whatever nbs are ) ? What’s that variation as a percent of the total ?
      BTW : it strikes me that a very significant difference between this CFC issue and CO2 is that CFCs really are man made molecules which wouldn’t be there otherwise . Without CO2 , it’s us that wouldn’t be here . And life exists only because the earth started with , I’ve read , as high as a 30% CO2 , 0% O2 atmosphere .

    • Thanks. Now I think I have a better overall sense of the matter, including both the seasonal and the CFC components.
      The fully sunlit Antarctic months have changed a little, but sunlight still keeps it pretty close to historical levels.
      So it looks like the bad news is October changes quite a lot, but the good news is that it always recovers pretty much completely after that, year after year.

      • So it looks like the bad news is October changes quite a lot, but the good news is that it always recovers pretty much completely after that, year after year.
        But no assurance that that would be the case if ‘business as usual’ had continued and we’d have been about double the concentration by now.

  17. Well if it’s a hole, why isn’t it called the nozone hole. I guess if you remove the solar UV, you don’t get ozone.
    Never mind, O2 works pretty well at absorbing UV and there is plenty of that in the atmosphere. I’ve read an essay by a well read chemist, who says that ozone is just the evidence, that oxygen is doing its job of absorbing solar UV.

  18. So UV always makes more ozone, even while it sometimes helps CFCs destroy ozone.
    Seems that UV always wins, either way.
    Or maybe UV always loses as far as giving humans incremental problems, beyond those which melanin deficient peoples always have had (even before CFCs), when transplanted into subtropical areas.

  19. I would have to say on a parting note: I conceded to Phil above that the destructive impact of CFCs on the ozone layer is probable. As I also stated several times, I do not have any trouble imagining that these highly reactive molecules being released into the atmosphere could cause damage.
    Honestly, the case Phil presents appears a slam dunk, and I think him for his input. Halogen compounds do catalyze the breakdown of O3, which could potentially upset the natural balance of this molecule in the upper atmosphere. There are beaucoups of naturally generated halogens as well, but it seems awfully coincidental that the column Cl equivalent has been falling steadily coincident with the Montreal protocol. The swift decline and recovery of O3 in the springtime at the South Pole appears to conform with the proffered mechanism.
    So, why do I remain a tad skeptical? Simple reason: lies and noble cause corruption. We have seen it so much in the AGW brouhaha. Data manipulated to confirm biases. Data hidden to forestall contention. Alternative mechanisms not considered. Professional ostracism to enforce orthodoxy.
    I do not have the time to investigate every one of Phil’s contentions. I have to take it on faith that the graphs of column Cl equivalent are on the up-and-up. I have to accept that the reduction since the early 90’s was a result of the Montreal protocol, and not part of a long term, natural variation. I have to accept that there are no better explanations for the springtime dip in the ozone curve. I essentially do because A) these are highly reaction compounds, and it is reasonable that they could cause damage B) it is not really a big deal as there are readily available CFC substitutes.
    So FWIW, until better information comes along, I come down probably about 85% convinced of the CFC link, and 15% still undecided.

    • Should have said: “I do not have the time to investigate every one of the pieces of evidence Phil relates”. I did not mean in any way to impugn Phil’s integrity.

    • Bart
      Your skepticism, prompted by cAGW and by the peculiar alarmist science, is widely shared. Any science that touches on environment must be scrutinized closely and confirmed before it can be accepted, and nothing taken for granted as truthful, such as the data.

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