The Sudden Stratospheric Warming 2010-2011

Redsunset

Im starting it a little early this year (JUST IN CASE SOMETHING EXCITING HAPPENS).

Link to last years thread which is a must read if you got no clue to what this is. CONTAINS ALOT OF INFO.

http://www.boards.ie/vbulletin/showthread.php?t=2055728070&highlight



It should be noted that this time around we are in a westerly QBO.


Right here is the current chart at 30hpa (Middle of stratosphere)

Note the rise of blue line last year in november,which was a record warming for the time of year and that set the stage for what was to come.







More ozone means a warmer stratosphere.
So we need plenty to get a good warming to hopefully weaken the Polar Vortex as in Slow it down then get it to reverse to an easterly. Everything sounds so simple in theory.






A view going back to Jan 09.

Su Campu

I was actually thinking about this yesterday and went and had a read back of that thread! We're all on the same wavelength - all ready for The Frigid Four......Nov, Dec, Jan, Feb!!!

admiralofthefleet

what does this mean to the lay person?

Redsunset

Great minds think alike,or so they say.

The Frigid Four,i like it.

There's so many different things happening at the moment.

I've no idea how this strong La Nina will affect matters but its gonna be interesting if we do get a warming to promote a negative Arctic Oscillation.

Im not liking the idea of the westerly QBO as it does not favour matters but i read somewhere that if in a mature westerly state (and it should be) it has be known to give cold winters combined with a low solar output.

I must find that again.

Min

Su Campu wrote: »

I was actually thinking about this yesterday and went and had a read back of that thread! We're all on the same wavelength - all ready for The Frigid Four......Nov, Dec, Jan, Feb!!!

lol at the frigid four, can't say I am looking forward to it.....good term though.

Min

admiralofthefleet wrote: »

what does this mean to the lay person?

I am sure I will be corrected if wrong but when the stratosphere warms in the Arctic it pushes colder weather down across our latitudes.

I think that is what I remember from that thread last year, sorry to my educators if I got it all wrong, I should have paid more attention if that is the case.

Su Campu

During the northern hemisphere winter, the cold airmass at the Pole generates the Polar Vortex, a deep westerly flow in the upper troposphere and stratosphere which circumnavigates the globe, with its centre at the Pole.

Sometimes, landmasses can disrupt the lower troposheric Rossby waves, which can extend into the stratopshere, causing warming, and hence a rise in geopotential, which forms a blocking setup in the stratosphere. This can cause a slow down or even reverse in the westerly flow, dragging some of the cold Arctic airmass southwards. This is the sort of thing that can bring us our coldest winter weather.

Redsunset

yep good explanations there.

Click the link for last year,it explains alot in laymans

A sudden stratospheric warming (SSW) is an event where the polar vortex of westerly winds in the Northern winter hemisphere abruptly (i.e. in a few days time) slows down or even reverses direction, accompanied by a rise of stratospheric temperature by several tens of degrees Kelvin. This is considered to be the most dramatic meteorological event in the stratosphere.


Classification and Description of Sudden Stratospheric Warmings
Typically stratospheric meteorologists classify SSWs into three categories:
#Major Warming
#Minor Warming
#Final Warming
Sometimes a fourth type of warming known as a Canadian Warming is included because of its unique structure and evolution, which distinguishes it from the other warmings.
Major Warmings
These occur when the westerly winds at 60N and 10hPa (geopotential height) reverse, i.e. become easterly. A complete disruption of the polar vortex is observed and the vortex will either be split into daughter vortices, or displaced from its normal location over the pole.

Minor Warmings
Minor warmings are similar to major warmings however they are less dramatic, the westerly winds are slowed, however do not reverse. Therefore a breakdown of the vortex is never observed.

Final Warmings The radiative cycle in the stratosphere means that during winter the mean flow is westerly and during summer it is easterly. A final warming occurs on this transition, so that the polar vortex winds change direction for the warming, however do not change back until the following winter. This is because the stratosphere has entered the summer easterly phase. It is final because another warming cannot occur over the summer, so it is the final warming of the current winter.

Sudden Stratospheric Warming Dynamics

In a usual northern-hemisphere winter , several minor warming events occur, with a major event occurring roughly every two years. One reason for major stratospheric warmings to occur in the Northern hemisphere is because orography and land-sea temperature contrasts are responsible for the generation of long (wavenumber 1 or 2) Rossby waves in the troposphere.

These waves travel upward to the stratosphere and are dissipated there, producing the warming by decelerating the mean flow. This is the reason that major warmings are only observed in the northern-hemisphere, with one exception. In 2002 a southern-hemisphere major warming was observed. This event to date is not fully understood.

There exists a link between sudden stratospheric warmings and the quasi-biennial oscillation: If the QBO is in its easterly phase, the atmospheric waveguide is modified in such a way that upward-propagating Rossby waves are focused on the polar vortex, intesifying their interaction with the mean flow. Thus, there exists a statistically significant imbalance between the frequency of sudden stratospheric warmings if these events are grouped according to the QBO phase (easterly or westerly).

Redsunset

http://www.esrl.noaa.gov/psd/data/correlation/qbo.data

QBO stats since 1948.

I see the great winter of 63 was an easterly QBO as strong as we just experienced.

Winter of 81-82 was also easterly.

Life cycle of the QBO-modulated 11-year solar cycle signals

in the Northern Hemispheric winter

http://www.nwra.com/resumes/baldwin/pubs/Lu_etal_QJ_2009.pdf

Abstract

Under wQBO, the polar stratospheric solar signals in zonal-mean zonal wind clearly lead and connect to those in the troposphere. In addition, the solar signals from the upper stratosphere tend to move faster and penetrate deeper down under wQBO than under eQBO.

Under wQBO, the solar perturbation on the NH winter circulation is likely to occur through its influence on SSWs in the polar region and compensating cooling at the Equator in the upper stratosphere. Under eQBO, the negative signals in the lower stratosphere are likely due to more SSWs occurring in eQBO/LS years; a process similar to that under wQBO might hold true in the upper stratosphere.

Thus, the strong solar signals in the upper to mid- polar stratosphere under eQBO represent a combined effect of recovery from SSWs occurring under eQBO/LS and positive temperature responses in the upper
stratosphere during the HS years.

Changes in the stratospheric polar region are primarily driven by anomalous wave forcing and residual circulation, which can be influenced either by internally generated dynamical perturbations of the atmosphere (e.g.
the ENSO and the QBO) or by external forcing (solar, volcanic eruption or increase of carbon dioxide). We find that the QBO-SC relationship becomes clearer when the ENSO is not strongly negative and such an ENSO perturbation effect is more noticeable under eQBO than

under wQBO.

derekon

redsunset wrote: »

http://www.esrl.noaa.gov/psd/data/correlation/qbo.data

QBO stats since 1948.

I see the great winter of 63 was an easterly QBO as strong as we just experienced.

Winter of 81-82 was also easterly.

Life cycle of the QBO-modulated 11-year solar cycle signals

in the Northern Hemispheric winter

http://www.nwra.com/resumes/baldwin/pubs/Lu_etal_QJ_2009.pdf

Abstract

Under wQBO, the polar stratospheric solar signals in zonal-mean zonal wind clearly lead and connect to those in the troposphere. In addition, the solar signals from the upper stratosphere tend to move faster and penetrate deeper down under wQBO than under eQBO.

Under wQBO, the solar perturbation on the NH winter circulation is likely to occur through its influence on SSWs in the polar region and compensating cooling at the Equator in the upper stratosphere. Under eQBO, the negative signals in the lower stratosphere are likely due to more SSWs occurring in eQBO/LS years; a process similar to that under wQBO might hold true in the upper stratosphere.

Thus, the strong solar signals in the upper to mid- polar stratosphere under eQBO represent a combined effect of recovery from SSWs occurring under eQBO/LS and positive temperature responses in the upper
stratosphere during the HS years.

Changes in the stratospheric polar region are primarily driven by anomalous wave forcing and residual circulation, which can be influenced either by internally generated dynamical perturbations of the atmosphere (e.g.
the ENSO and the QBO) or by external forcing (solar, volcanic eruption or increase of carbon dioxide). We find that the QBO-SC relationship becomes clearer when the ENSO is not strongly negative and such an ENSO perturbation effect is more noticeable under eQBO than

under wQBO.

What does all this means? Are we in for a colder winter?

Derek

Redsunset

Nobody can say for certain that we are in for a colder than normal winter but what we can do is look at all the signals and look back at previous winters when conditions were similar to see if they recreate the same outcome.

As regards the westerly QBO which we are now experiencing,
Well if you look back to around Jan 09 in above chart in post 1 you will see a record warming which was indeed a Major Midwinter Warming.

This did not favour any blocking, however due to its extreme nature the record warming changed the PV from westerly winds to easterly which in turn split the Polar Vortex into Daughter vortices and the intensity of easterly winds propagated down to the troposphere which gave us our Feb 2nd snowfall in the east.

Here's a little vid to show you what happened. enjoy.

https://www.youtube.com/watch?v=-avwKDhXIrQ

So anything can happen really.

derekon

Thanks for the explanation and video Redsunset!

Derek

nacho libre

If there are no signs of major warming taking place and the QBO is westerly, you'd wonder why netweather and positive solutions are indicating this winter will be colder than normal and dry. Are they reading too much into the effect of low solar activity can have?

Redsunset

nacho libre wrote: »

If there are no signs of major warming taking place and the QBO is westerly, you'd wonder why netweather and positive solutions are indicating this winter will be colder than normal and dry. Are they reading too much into the effect of low solar activity can have?

Remember i've started this thread early,so nothing will happen at the moment.

Even the sites which cover this event don't start till Nov 1st.

Remember too that the record warming in Jan 09 happened during a westerly QBO.

Wait and see.

Redsunset

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html

Winter Diagnostics

The aim of this web page is to inform all interested researchers, enaged in
various studies connected with stratospheric circulation modelling and analysis,
tropospheric/stratospheric interactions, stratospheric ozone and climate studies,
about the current state of the northern hemisphere stratospheric circulation in
the period of November 01 - April 30.
NOTE: The current ECMWF analyses will be distributed via WWW in the
forthcoming season 01 November 2010 - 30 April 2011 only!

IvySlayer

Woah woah lads still not dumb enough for me.

Does it mean it's going to get colder?

nacho libre

IvySlayer wrote: »

Woah woah lads still not dumb enough for me.

Does it mean it's going to get colder?

if the jetstream stays to the south of us during the Winter months, there is a good chance of a cold winter overall, like that of 2008/09. places like portugal then will have the mild and wet weather we'd normally get in winter.

what redsunset is basically hoping for is that if this major warming in the stratosphere happens our weather will eventually start to come from the east/ northeast- this is the direction it needs to be coming from if he, and others in the east of Ireland, wants to see cold and snow.
otherwise, unless a polar low comes down over Ireland, he is unlikely to see much snow.

forkassed

There are signs of it happening earlier..

The models are definitely picking up on a cold blast in a week or so due to a strong Greenland High.

Personally i would rather see this set up in December but who knows we may get stuck in a pattern like this for the next 4 months or so:)

Su Campu

A very interesting read here

Redsunset

Right as of Nov 1st the Strat watch season began.
Encouraging to see a slight warming,can we get another like Nov last year. Doubt it but you never know.



And if course we'll keep an eye on the Zonal winds.

Redsunset

Su Campu posted this.Im giving this thread a bump with this info.


Looks like we could be heading into a prolonged pattern shift, with signs of the first split 30hPa vortex developing in the next week. Not a classic, but should lead to increased meridionality, meaning if that northeasterly sets up, it could stay.....then again, a small shift could mean someone else gets it and we're stuck in a milder regime....

One to keep an eye on....

T + 00hrs


T + 240hrs

nacho libre

redsunset wrote: »

Su Campu posted this.Im giving this thread a bump with this info.


Looks like we could be heading into a prolonged pattern shift, with signs of the first split 30hPa vortex developing in the next week. Not a classic, but should lead to increased meridionality, meaning if that northeasterly sets up, it could stay.....then again, a small shift could mean someone else gets it and we're stuck in a milder regime....

One to keep an eye on....

T + 00hrs


T + 240hrs

Has the small bit of warming been enough to cause this split? or is there some other factors at play?

Redsunset

nacho libre wrote: »

Has the small bit of warming been enough to cause this split? or is there some other factors at play?

It certainly looks to have disrupted the Polar Votex.

Remember it does not need to warm much at the beginning of November to reach record levels and although not as strong as last time it was just shy of reaching new heights again.
Certainly interesting few months ahead

nacho libre

just read this over on netweather:

"For me, I think that it is highly likely that by the middle of December the Atlantic will be having a far greater influence on our weather. We would need to see quick changes in the cooling stratosphere for this not to be the case imo. Once the Atlantic gets in, it may be difficult to get deep cold air moving south of the pole as the strength of the PV may prevent further northern blocking."

let's hope he's wrong!

Kippure

nacho libre wrote: »

just read this over on netweather:

"For me, I think that it is highly likely that by the middle of December the Atlantic will be having a far greater influence on our weather. We would need to see quick changes in the cooling stratosphere for this not to be the case imo. Once the Atlantic gets in, it may be difficult to get deep cold air moving south of the pole as the strength of the PV may prevent further northern blocking."

let's hope he's wrong!

Wonder what MT thinks of that?

Redsunset

This could be the answer

Glacier point posted this on NW so i copied it.

Here's why the temperature of the stratosphere matters going into the depth of the polar winter.

For years with a cold 30mb temperature in December - January period:

The proceeding January - February 500mb geoptential height anomaly:

Note the unusually high proportion of Nina winters there and absence of blocking (although the +ve height anomaly in the Atlantic is interesting).

Now, the inverted test. Years with a warm 30mb temperature December - January period:

The proceeding January - February 500mb geopotential height anomaly:

maquiladora

redsunset wrote: »

This could be the answer

So its not looking good, blocking wise, for us this winter then?

Kippure

maquiladora wrote: »

So its not looking good, blocking wise, for us this winter then?

Basically theres a strenghting nina signal in 10 to 15 days time i think...:eek:

Redsunset

Not looking good for further Greenland blocking but he does point out some height anomaly in the mid atlantic and they still can pave the way for cold in my opinion.Im a little worried now.

nacho libre

I was told over on netweather that stratospheric warming doesn't always translate into a blocking pattern. A major stratospheric warming event that took place in February 2009 was cited as an example of this.

So let's just hope that the continued low solar activity has a bigger influence than the guy who wrote that thinks. In fact I recall in another post he(GP) did suggest that there was a possible correlation between the jet going south and the low solar activity. If this is the case then hopefully blocking can occur independent of stratospheric warming. If it doesn't then it's hard to see how forecasts of a cold winter, overall, can be realised

Redsunset

The major warming started in Jan 09 and yes there was no blocking but the easterlies were so strong in the stratosphere that they eventually made their way down to the troposphere and gave people like me on the east feb 2nd snow. The Qbo was westerly like now. So all is never lost.

This is what i was receiving that day.




Feb 2nd snow.JPG