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#1474510 - 23/10/2018 00:36 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
marakai Online   content
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Registered: 05/01/2006
Posts: 1988
Loc: Maryfarms NQ
A gentle stroll through EP flux theory.

https://cims.nyu.edu/~obuhler/Oliver_Buhler/Publications_files/EPFluxThyEJFM14.pdf

A lot of references at the bottom.

Also chapter 11 here http://www.staff.science.uu.nl/~delde102/AtmosphericDynamics.htm


Edited by marakai (23/10/2018 00:45)

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#1474554 - 23/10/2018 22:49 Re: Stratospheric sudden warmings (SSWs) [Re: marakai]
snowbooby Offline
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Registered: 11/05/2016
Posts: 243
Originally Posted By: marakai
A gentle stroll through EP flux theory.

https://cims.nyu.edu/~obuhler/Oliver_Buhler/Publications_files/EPFluxThyEJFM14.pdf

A lot of references at the bottom.

Also chapter 11 here http://www.staff.science.uu.nl/~delde102/AtmosphericDynamics.htm


thanks

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#1474607 - 24/10/2018 23:00 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbooby Offline
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Registered: 11/05/2016
Posts: 243
That warming mentioned earlier this month showing on charts of Tokyo Climate Centre - it's position in mid to high stratosphere is more precisely located on noaa's chart.
After the event cold anomalies again re-assert and continue their migration downwards. http://www.cpc.ncep.noaa.gov/products/st...OND_SH_2018.png

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#1475696 - 11/11/2018 11:34 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbooby Offline
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Registered: 11/05/2016
Posts: 243
strong Zonal Wave 1,2 & 3 activity (3 prominent) early Nov which created strong deformation in gph and wind fields of stratospheric polar vortex. (Both fields elongated and briefly pivoted from continent to centre closer to 60s). PV in 20hPa region showing strong deformation by about 7 Nov.

In space of 10 days circumpolar wind speed @ 10 hPa will have roughly halved according to gfs forecasts. Might represent the first indication of the beginning of the approach of the final warming event for this year.


Edited by snowbooby (11/11/2018 11:35)

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#1476103 - 19/11/2018 09:14 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbooby Offline
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Registered: 11/05/2016
Posts: 243
Planetary wave activity(as evidenced by EP flux) for october was anomalously negative which might help explain any delay if the sspv is later getting to breakdown this year.

The upsurge in activity in early nov produced what probably will qualify as a major warming(I think the criteria is 25C+ within period of a week) though I haven't looked in detail - last forecast(nasa) has 10hPa circumpolar wind dying by about 24/11...

One criteria for final warming I've seen -and there are others involving different parameters so this might not be universally accepted - is for the winds @ 50hPa to drop below 1m/s - so the breakdown in the winds has to migrate downwards for the final warming to complete.


Edited by snowbooby (19/11/2018 09:19)

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#1476158 - 19/11/2018 21:27 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
marakai Online   content
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Registered: 05/01/2006
Posts: 1988
Loc: Maryfarms NQ
Ever wonder if Stratospheric sudden warming was an escape of heat into space? Out instead of in?

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#1476182 - 20/11/2018 01:09 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
marakai Online   content
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Registered: 05/01/2006
Posts: 1988
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Interesting :https://arxiv.org/ftp/arxiv/papers/1811/1811.06842.pdf

Temperature and pressure variability
in mid-latitude low atmosphere and stratosphere-ionosphere coupling.

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#1476199 - 20/11/2018 10:54 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
CoastalStorm22 Offline
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Registered: 10/07/2006
Posts: 2885
Loc: Lane Cove, Sydney, NSW
Current state of affairs





Zonal Wind



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Lane Cove - Dee Why - Wyoming

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#1476279 - 20/11/2018 22:42 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbooby Offline
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Registered: 11/05/2016
Posts: 243
That's interesting, the u values @50hPa posted yesterday(#1476103) I got from
https://acd-ext.gsfc.nasa.gov/Data_services/met/ann_data.html
You have to input into the menu. I think from memory it was [-90,-60]
Unfortunately I cant link to it from the machine I'm presently on.

According to http://www.cpc.ncep.noaa.gov/products/st...OND_SH_2018.png
(Again not certain link is working) mean U is currently in the range of 20-30 m/s though it is zonal mean[-80,-50]

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#1476327 - 21/11/2018 12:26 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
Mike Hauber Offline
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Posts: 3440
Loc: Buderim
So a major SSW is underway for the Southern Hemisphere?

And this might have something to do with the unusual cut off low pressure activity forecast over the next week or so, with multiple large cut off lows near Australia for much of the current forecast period?

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#1476332 - 21/11/2018 13:32 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
CoastalStorm22 Offline
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Registered: 10/07/2006
Posts: 2885
Loc: Lane Cove, Sydney, NSW
Given the time of year I'd say the current warming is the final warming before the vortex breaks up for summer? I have also noted the ozone hole is in a state of rapid decay now, which is not all that unusual at this time in Nov, however what is interesting is this years hole was larger than normal which would usually mean a longer lived vortex/ozone hole. At the current rate of decay it will probably be almost closed by the end of the month.

We've dropped from 20.52 million km in size on the 4th Nov to just 9.12 million km at the last update on 18th. I've only been closely watching the annual hole now for 2yrs, but that seems like a fairly rapid drop to me. Correct me if I'm wrong of course.
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#1476417 - 21/11/2018 23:16 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbooby Offline
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Registered: 11/05/2016
Posts: 243
Thanks CS for the charts

14k change on the first chart starting about 9/11, mightn't qualifiy as a major ssw - I think it has to occur over one week's duration and this one I think is a little longer - a pedantic point.

For a great animation see
http://www.pa.op.dlr.de/arctic/ecmwf.php?im=19
(hope link works - other wise search on Andreas Dornbrack)
I recommend trying the gph as well as pv animation, because the gph field is overlaid with the temp field and the warming looks particularly impressive when it comes(location south east of NZ - activity sourced from a blocking high ealier this month?)
but be quick because the start date of the animation moves forward each day. I think there was an earlier more impressive warming(on the charts) but the date of the starting window has already moved beyond it.

The nasa link I posted above had mzw@50hPa fading out by about the 24/11(that was last saturday's forecast).

The axis of the sspv has not been consistently tethered over the antarctic continent in response to recent warming and currently looks to have a disproportionate bias towards the eastern hemisphere. There was a big shift in the generally circular, to a more erractic ellipsoid, shape and circulation about 8/11.


The point of intersection of the winds associated with the vortex abruptly shifting in the zonal "corridor" in phase with this distortion in circulation - it's nicely portrayed in CS22's final chart.(ie: the spv boundary winds shift from > -60 to ~ -85 in short time - evidence of asymetrical spv oscillation?

It is a fascinating region of the atmosphere - as much for the idiosyncratic lapse rate which is like a reversed mirror image of the troposphere. While tracing connection between the two is of huge interest, the detail of interaction is still a mystery to me.

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#1476466 - 22/11/2018 11:09 Re: Stratospheric sudden warmings (SSWs) [Re: CoastalStorm22]
snowbooby Offline
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Registered: 11/05/2016
Posts: 243
Originally Posted By: CoastalStorm22


We've dropped from 20.52 million km in size on the 4th Nov to just 9.12 million km at the last update on 18th. I've only been closely watching the annual hole now for 2yrs, but that seems like a fairly rapid drop to me. Correct me if I'm wrong of course.



I only have cpc chart updated to 4/11.
In case you haven't got them, all the completed annual charts back as far as 79-80 are available.
http://www.cpc.ncep.noaa.gov/products/stratosphere/polar/polar.shtml#plot1

I dont know if this year's rate of decline is more or less rapid than mean - perhaps for recent years and particularly from a hole size at the upper end of the range it is.

2011, though a much smaller hole at the time(but had been near the upper end of the range leading up to this point), plummeted from ~13m sq km's to 3m in a very short period.

The rate of decline I wonder if it is correlated directly to the concentration of ozone in the collar region - I imagine it might be though I don't have any data to back that up with.

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#1476768 - 24/11/2018 19:39 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbooby Offline
Weather Freak

Registered: 11/05/2016
Posts: 243
Figures I've pulled from nasa show(these are all zonal mean for -90,-60

10hPa - +18.3k between 1/10 and 5/10

30hPa - +10.5k between 1/10 and 6/10

50hPa - +4.52k between 1/10 and 7/10

The initial warming strikes high.

compared to novembers, the proportionate increase in temp below 10 hPa is greater.

10hPa - +13.54k between 5/11 and 12/11

30hPa - +13.20k "

50hPa - +9.42k "


Saturdays(24th) forecast for zonal wind @ 50hPa = 14.63 m/s on 1/12

These forecasts do jump around a bit but the few forecasts I've seen maybe the integrity of vortex in the lower stratosphere-upper troposphere is going to hold together a little longer than I thought a few days ago.
Have a look at
http://www.cpc.ncep.noaa.gov/products/st...ALL_SH_2018.png

Puts it all into one glance perspective(as far as temps are concerned)

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#1477750 - 28/11/2018 23:59 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
marakai Online   content
Weatherzone Addict

Registered: 05/01/2006
Posts: 1988
Loc: Maryfarms NQ
This might be interesting for some here.
https://www.researchgate.net/publication..._Solar_Activity

The atmosphere and the ionosphere are tightly (two-way) coupled by plasma–neutral interactions during quiet and as well as geomagnetically disturbed conditions. In this context, “two-way”does not indicate upward–downward directions in the atmosphere; namely it means that neutrals can impact plasma processes as well as plasma can drive neutral dynamics, depending on the latitude.
Such plasma-neutral interactions lead to frictional heating of the neutral atmosphere by Joule heating, which significantly influ-ences the structure of the upper atmosphere (Yiğit and Ridley,
2011).

.


Edited by marakai (29/11/2018 00:01)

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