SH Polar Vortex

[Pmt111500]

Normal in Antarctica an SSW is not. In the 50 years since the technology allowed us to "see" these events, they happen every few years in the Arctic but only 2 in Antarctica, 2002 & 2009, and 2009 was minor.

Standing corrected and this is indeed an Event.

[philopek]

Cor blimey......

But you need your eyesight to provide further precious content

But seriously, do you happen to know a good site where to read and study about the consequences?

[gerontocrat]

Cor blimey......

But you need your eyesight to provide further precious content

But seriously, do you happen to know a good site where to read and study about the consequences?

Tried by googling "effects of SSW" & variations of that.
There are a forest of technical articles about the effects of SSWs in the North. But I could not find one which was in plain enough English and about effects on weather down where we are, to be comprehensible by me. Lots of references to the 2002 SSW in the South but all totally technical.

So I simply wait to see what happens? Cold in S America? More drought in Aussieland? Increased sea ice melt in one place, slow melt or even gain in another? Who knows?

[philopek]

Cor blimey......

But you need your eyesight to provide further precious content

But seriously, do you happen to know a good site where to read and study about the consequences?

Tried by googling "effects of SSW" & variations of that.
There are a forest of technical articles about the effects of SSWs in the North. But I could not find one which was in plain enough English and about effects on weather down where we are, to be comprehensible by me. Lots of references to the 2002 SSW in the South but all totally technical.

So I simply wait to see what happens? Cold in S America? More drought in Aussieland? Increased sea ice melt in one place, slow melt or even gain in another? Who knows?

Thanks, came up blank as well which is why I asked, hence let's wait ans see as suggested

[gerontocrat]

Temperature anomaly at the pole diminishing, vortex centre still on the move.

[gerontocrat]

But seriously, do you happen to know a good site where to read and study about the consequences?

Found this by the Aussie Met Office

https://theconversation.com/the-air-above-antarctica-is-suddenly-getting-warmer-heres-what-it-means-for-australia-123080

[sark]

https://twitter.com/DrAHButler/status/1176520070182375426

some discussion on the still evolving character of this SSW event

[philopek]

But seriously, do you happen to know a good site where to read and study about the consequences?

Found this by the Aussie Met Office

https://theconversation.com/the-air-above-antarctica-is-suddenly-getting-warmer-heres-what-it-means-for-australia-123080

THX a lot, very much appreciated

[gerontocrat]

The SSW event is still persisting.

The centre of the polar vortex moved into the Weddell Sea and is now wandering between there and the pole.

The question is - what will be the effect down below on the surface?

The GFS images below suggest in the next three days the tip of South America switches from warm to cold (as predicted) and extreme -ve temperature anomalies developing in the Weddell Sea, with contrasting extreme +ve temperature anomalies developing elsewhere.

Later days show this contrast expanding and deepening EDIT until by Oct 5 Antarctica is a tale of 2 halves.

Question is - is the SSW the cause?

[gerontocrat]

....Later days show this contrast expanding and deepening until by Oct 5 Antarctica is a tale of 2 halves.

[gerontocrat]

The SSW has not died - revived a bit @ 30 hPA.

Voretx centre well north of the Pole,
Secondary Vortex well south of the pole.

Affecting NZ
https://www.stuff.co.nz/national/116268261/sharp-cold-snaps-to-start-october-with-more-expected-over-spring
'Sharp cold snaps' to start October with more expected over spring

Spring looks set to continue feeling more like winter at times, with Niwa expecting several "sharp cold snaps" for the first half of October.

There's also a chance that, even as temperatures climb into December, "the door to the Southern Ocean may remain 'ajar', allowing air masses from the south to continually influence New Zealand's patterns".

In it's Seasonal Climate Outlook for the next three months, published on Wednesday, Niwa said New Zealand's coastal sea temperatures were cooler than average in all regions for the first time since January 2017. That factor was expected to influence air temperatures in the period from October to December.

Several models indicated that in the coming season there was a good chance of higher than normal air pressure in the polar region. That would allow the development of a ring of lower than normal pressure in the Southern Hemisphere mid-latitudes, Niwa said. That would provide the possible opening for cold air masses to the south to keep affecting New Zealand.

It was the strongest SSW on record for the Southern Hemisphere and only the second major event - the previous major SSW was in September 2002.

While the stratosphere did not directly connect with the troposphere - the layer we live in - as it did in 2002, Niwa linked some weather impacts to the SSW.

Weather patterns across the Southern Hemisphere mid-latitudes were affected, with "very cold" air masses able to sweep north, Niwa said. Chile, Argentina, Uruguay, New Zealand, and southern Australia experienced colder than average temperatures during September.

[SteveMDFP]

The SSW has not died - revived a bit @ 30 hPA.

Voretx centre well north of the Pole,
Secondary Vortex well south of the pole.

I'm a tad mystified where these locations would be on any map.

[nanning]

<snip>
Secondary Vortex well south of the pole.

Is this Antarctica you mean?

[gerontocrat]

Whoops. Brain re-boot ................ done.

Ok, main vortex centered North of the S Pole at around 0 degrees longitude.

Second vortex centered North of the S Pole close to 180 degrees longitude.

[blumenkraft]

Is this in the west or the east?

PS: Kudos on the fast reboot there, Gerontocrat. It takes me like 5 dots longer.

[gerontocrat]

Is this in the west or the east?

my brain hurts.

Don't know, don't care, lost the will to live. Nurse !!!!

[blumenkraft]

Oh, boi! 

[Rodius]

The effects of this event is bearing out in the forecasts.
Click the link to see Australia covered in red.... which represents 80% chance of being above medium temp.

I have never seen this happen on a country level and it genuinely scares me for the coming summer here.


http://www.bom.gov.au/climate/outlooks/#/temperature/maximum/median/seasonal/0

[vox_mundi]

Extraordinarily Warm Temperatures Above Antarctica Cause Hot and Dry Extremes in Australia, Researchers Warn
https://phys.org/news/2019-10-extraordinarily-temperatures-antarctica-hot-extremes.html

The study shows that changes in springtime winds high above the South Pole can have a far-reaching and crucial effect on surface climate in Australia—a weakening of these winds in spring results in warmer temperatures, lower rainfall and an increase in heatwave and fire-prone weather conditions (especially across NSW and southern QLD) over late spring to early summer.

... They found that the chance for hot and dry extremes to occur appeared to increase by about four to eight times when a significant polar vortex-weakening event occurred.

"Our study is significant because it is the first of its kind to identify and quantify a direct link between variations in the Antarctic polar vortex in spring and Australian hot and dry extremes from late spring to early summer"

"This has major implications for the predictability of extreme climate in Australia, as well as possibly other regions of the Southern Hemisphere."

The study, led by Dr. Eun-Pa Lim at the Bureau of Meteorology, is published today in the prestigious journal Nature Geoscience.


Changes in the likelihood of extreme high Tmax, low rainfall and high wildfire danger during the nine polar vortex weakening years.

Eun-Pa Lim et al. Australian hot and dry extremes induced by weakenings of the stratospheric polar vortex, Nature Geoscience (2019)


Fig. 5: Circulation and cloud cover changes over Australia during the nine polar vortex weakening years.

[gerontocrat]

An effect of the SSW

https://www.bbc.co.uk/news/science-environment-49965556
'Ozone hole vigilance still required'

The recovery of the ozone layer over Antarctica cannot be taken for granted and requires constant vigilance.

That's the message from Dr Jonathan Shanklin, one of the scientists who first documented the annual thinning of the protective gas in the 1980s.

This year's "hole" in the stratosphere high above the White Continent is the smallest in three decades.

It's welcome, says Dr Shanklin, but we should really only view it as an anomaly.

The better than expected levels of ozone have been attributed to a sudden warming at high altitudes, which can occasionally happen.

This has worked to stymie the chemical reactions that usually destroy ozone 15-30km above the planet.

"To see whether international treaties are working or not, you need to look at the long term," Dr Shanklin told BBC News.

"A quick glance this year might lead you to think we've fixed the ozone hole. We haven't. And although things are improving, there are still some countries out there who are manufacturing chlorofluorocarbons (CFCs), the chemicals that have been responsible for the problem. We cannot be complacent."

[kassy]

The Antarctic ozone hole is the smallest since it was discovered

....

On September 8, the ozone hole reached a peak of 6.3 million square miles and then shrank to less than 3.9 million square miles, according to the report. Usually, the hole would grow to reach 8 million square miles.

...

About 12 miles up from the surface, temperatures were 29 degrees Fahrenheit warmer, making it the warmest year since observations began. In addition to keeping ozone depletion minimal, the weather systems responsible for the temperature shift reduced the jet stream around Antarctica from 161 miles per hour to 67. This weakened the polar vortex and let it drop down into the lower stratosphere.
This caused less clouds to form and air rich in ozone was actually brought up above the ozone hole.
 
and more on:
https://us.cnn.com/2019/10/21/world/antarctic-ozone-hole-shrinks-scn-trnd/index.html

[Steven]

Three peculiar Antarctic ozone hole seasons in a row: what we know

https://atmosphere.copernicus.eu/three-peculiar-antarctic-ozone-hole-seasons-row-what-we-know

The Copernicus Atmosphere Monitoring Service (CAMS) data shows the 2022 ozone hole closed later than most of those of the previous 40 years and, despite the signs of recovery of the ozone layer, it is still within the 15 largest in our record dating back to 1979.
...
While the average ozone hole area generally decreases quickly in October and even faster in November, in the last three years we have seen the ozone hole persisting into November and closing well into December. 

The article also discusses the links between polar vortex and ozone hole.  In particular, in the last 3 years the polar vortex remained stronger than normal in October (stratospheric warming happened later than normal), which caused the ozone hole to survive longer than normal.





Ozone hole size (color) for each year (horizontal axis) and date (vertical axis):



Correlation between polar vortex strength (annual average) and ozone hole size (annual maximum):

[Steven]

Fears over Antarctic sea ice as yearly ozone layer hole forms ‘very early’

https://www.theguardian.com/environment/2023/aug/08/fears-over-antarctic-sea-ice-as-yearly-ozone-layer-hole-forms-very-early

Satellite data from the European Centre for Medium-Range Weather Forecasts suggests the hole has already begun to form over Antarctica.

...

The ozone hole is usually smaller during El Niño years, but modelling by Jucker and collaborators, including Chris Lucas of the Australian Bureau of Meteorology, has suggested it will be larger than usual in 2023, due to long-lasting atmospheric changes after the undersea Tonga volcano explosion in January last year. The modelling has not yet been peer-reviewed.

...

Jucker said he was concerned about the impact of the hole on Antarctic sea ice, which has hit record lows over the past two years.

“The more UV radiation that reaches Antarctica [and] the Southern Ocean means that there is more energy available to melt ice,” Jucker said. “Now that we have so little sea ice, instead of [reflective] white ice there is very dark blue ocean.

“There is a risk that the Southern Ocean would then heat up even more and then indirectly melt more ice because the water next to the ice is warmer.”

...

A larger ozone hole may also lead to a positive phase of a climate driver called the southern annular mode (Sam). “A positive Sam would shift … winds further poleward,” Jucker said. “Stronger winds come further to[wards] the pole and they can push away more ice.”

Eun-Pa Lim, a senior research scientist at the BoM, said there was “large uncertainty in which direction the Sam will swing in spring and summer at this stage”, because an El Niño could push the Sam towards a negative phase.

“It is also uncertain how the current early development of the Antarctic ozone hole will impact the Antarctic sea ice via a change in Sam.”