A new ozone hole record?
Perhaps not quite ...
With minor edits 21 Dec 2023
On December 5 a new ozone-hole record was nearly reached which may have important implications for UV irradiances over Antarctica (and possibly over a wider area, including New Zealand).
As you can see from the above plots, the peak ozone depletion has long-since passed. The largest in area was Sept 21, and the lowest ozone value occurred on October 3. But on December 5, the size of the ozone hole nearly became larger than for this date in any previous year. I’ve been watching it carefully since, but it looks as if it won’t quite get across the line as an all-time record.
Way back in early September, scientists predicted that this year’s hole would be large because of the effects of the Tongan eruption. I was a bit sceptical at the time, and later reported that, while relatively large at its peak, it was nowhere near a record size. We now know that it was about the 12th largest ozone hole one record. It also lasted longer than usual: with the near all-time record in early December. NASA recently described it as only ‘modest’, which may have more to do with inter-agency rivalries than anything else, or perhaps with dispelling media hype. But it was undeniably stronger than in recent years. It’s great news that the September prediction was essentially correct (if slightly beat-up by the media). To me, it’s a strong validation of our community’s understanding of the chemistry.
In my last post on this topic I speculated that the polar vortex was likely to break down soon. Well, I have to admit that I was wrong there. It remained intact until early mid-December, and the ozone hole is only now starting to break down.
Because of the late break-up time, I know that my colleague Bernhard Germar in San Diego will be eagerly poring over his UV data from Antarctica. Old records there may have been surpassed because of these low ozone amounts persisting into the summer when sun elevation angles are larger. In particular, Palmer Station - on the Antarctic Peninsula that extends up towards South America - was right under the ozone hole on 5 December.
We don’t yet know if this year’s hole will break any UV records. The highest UV ever measured at Palmer is UVI = 14 (more even than in San Diego and comparable with the highest anywhere in New Zealand). It will have to be a sunny day was well as having low ozone for that record to be broken. Even if it is surpassed, it’s unlikely to have measurable effects at populated areas, though the late break-up of the hole does increase the risk as fragments of ozone-poor air disperse to lower latitudes during the summer when UV levels are already high. But you never know …
The good news is that in the years ahead the size of the springtime ozone hole will gradually diminish, as the amount of chlorine in the atmosphere reduces. This year is just a glitch.
But the UV risk will remain. Keep your sunblock handy (this summer especially).
Yes Richard, one and the same in gmail. (so you got my direct email then) not elsewhere. I avoid social media generally. For your comments I made an exception. Sorry I posted fast without grammar checking, Your posting stimulated me to reflect and write in fast streaming mode. I'll clean up if you like.
Thanks for link to "Saving our Skins". I'll definitely read it. In fair disclosure, Yes, I'm writing a historical fiction, trying to suck all readers into heroism in a slower subtle way, title at this point is "Chasing Snow Fairies in the Antarctic Sky". It's every-way got potential of being like a James Bond story on steroids, and true events. Biggest hurdle is I am not anywhere level of an Iam Fleming level writer.
Ironically biggest hole in a complete story line, what exactly motivated bloody dictator Pinochet to allow US agencies base a very large science mission (AAOE) in Punta Areas in 86-87, in a period he was in bitter conflict with Barnes, US ambassador to Chile. I've got hints visiting Chile, chatting with Chile's top climate scientist (University of Washington grad - who attempted to ask retired Chilean scientists there during Pinochet for possible motivations to no avail) interviews, even resorting to Chilian Human rights sources. All I know it only had to do with having US's (NASA's) U2 to be based in Punta Arenas, absolutely nothing to do with Ozone, (they had not a clue), definitely not publicity, just the opposite it seams. It's a real enigma hole in plot motivations. So contradictory a group so violent act so opposite of a manner. I got one rather nefarious idea of desperation developing in part of Pinochet henchmen in that time frame what was the scheme knowing the times and lots of reading between the lines. Sound too far out there to me. May there is a real darks reason buried bitterly with executions later on that I've found nothing. CBC has Pinochet victim count at 40018. More I read, worst terrorist act on US soil till Twin Tower bombings was directed by Pinochet and more, those scientists in NOAA and NASA just post Falklands never realized how incredibly dangerous of a hair trigger of unimaginable violence they were exposed to being in Punta Arenas for Ozone data. I got to missing something.
Try this link on Goddard's black swan paper. I'll leave further comments for a less public means.
https://www.sciencedirect.com/science/article/pii/S1631071318301196.
Actually, Mexico’s El Chichon eruption in 1982 produced such a drop in measured Ozone in the area where the Shuttle launches that it was major factor NASA TOMS missed detection of the Ozone hole over Antartica.
When Regan in 81 came into power everything remotely environmental came the microscope and much cutback and pressure to cut back. Plus Reagan administration had major push eliminate in-house non military tasks, remaining civil servants were no longer to do science but be contract monitors in NASA. NASA had huge brain drain of employees and money to work issues.
Effect was TOMs and Anderson’s Ozone instruments (essential later for Montreal Accord) were weeks from being canceled, except Sherry Rowland thru Susan Solomon had just learned of Halley Bay 50%+ and increasing spring Ozone Loss and were able to convince Tom Watson to push to keep them around another year. (Susan happened to be reviewer of that pivotal paper, one Joe Farman feared publishing as it had extremely high risk of causing closing of BAS and Halley bay Embarrassing Margaret Thatcher who at that time anti environmental politically).
In effect, the Ozone quest was very much like the fellowship of the ring quest in Lord of the Rings, on a precipitous edge, teetering to fail against insurmountable odds.
So in this scary career threatening environment Toms invested totally in understanding Chichon eruption strangeness that threatened to undo NASA’s bread and butter Shuttle. Turns out NASA had extremely politically sensitive analysis perhaps like SST chlorine in solid boosters could greatly impact Ozone. In fact did around each launch and the Shuttle program internal to NASA funded CFC and shuttle exhaust measurements for many years all over to start to sort this out.
So absolutely to save their skins under reduced staff facing layoffs, TOMs staff did what absolutely necessary understand El Chichon. Antarctica issue that they absolutely had no time and virtually no support was guessed to be a secondary satellite calibration issue under extremely low light, so it was out of necessity put on back burner.
The Goddard staff wrote a paper calling events a Black Swan event, blaming tape processing time. I worked different secondary instruments on Nimbus around same time, it’s like few 9 track tapes on regular mail from Fairbanks Alaska, it’s not the shipping or couple hours of reading a tape, it’s the many many man hours debug and analysis, all that absolutely priority was El Chichon eruption.