Stratosphere Temperature Watch 2014/2015

[Recretos]

I assume this is the guy that usually gives the interpretations of the WSI charts.

What he is trying to say, is that this warming is a 3 sigma event, which means the warming anomaly is 3 times the standard deviation.

The reason it is so high, is because usually or climatologicaly speaking, there is the vortex core over that region with temps from -65 to -80 or less.

[sebastiaan1973]

Zonal winds will increase in time, but are on a lower level than earlier in the winter.

Edited January 9, 2015 by sebastiaan1973

[Relativistic]

Chiono was short and precise. But I will also add my 2 cents.

I am no physician by any means, so I can only try to explain it in layman terms.

I am going to extend this so it also might be a simple crash course in strat wind zonality for others too. It is something I explained before, but oh well, I have a few minutes to spare.

 

 

Thanks!! Very helpful

[polar vortex]

New poster here I thought I would offer my musings on the warming that has and is taking place in the mid to upper stratosphere. 

This strong warming will surely have ramifications as it makes it way down eventually into the troposphere.Atlantic ridging would surely  benefit from the downwelling warming that will be some days away yet from showing its hand in the troposphere but the model outputs are now grasping this I think.

The stratosphere charts showed lacklustre geopotential height rises due to the warming but this may well be a very different story in the troposphere. Therefore it could be a type stratosphere/troposphere 

disconnect in that respect. Any type of MJO wave into the troposphere/stratosphere (the stronger the 

better) would also aid in stronger ridge building and amplification up north.

 

[Paul123]

I still don't understand why this 8 januari warming hasn't reversed the 10 hpa wind. It has been quite a substantial warming and leaves behind a very disturbed temperature pattern. Yet it creates only a relatively small change in de stratospheric windfield. 

 

 

Perhaps it is due to the exteme low tropospheric heights below the warming region or are there any other causes?

 

 

 

 

 

 

 

 

 

[chionomaniac]

I still don't understand why this 8 januari warming hasn't reversed the 10 hpa wind. It has been quite a substantial warming and leaves behind a very disturbed temperature pattern. Yet it creates only a relatively small change in de stratospheric windfield. 

 

warming.JPGWarming 3.JPG

 

Perhaps it is due to the exteme low tropospheric heights below the warming region or are there any other causes?

 

Warming 2.JPG

It was because the vortex was split, the warming successfully wrapped around and destroyed the Canadian daughter vortex, whilst leaving the Siberian daughter unaffected. This Siberian daughter then increases in strength and returns to the pole. It is a case where I believe the strong wave 2 activity and subsequent split vortex has inhibited the possibility of a (major) SSW. 

 

The Canadian daughter vortex has pretty much undergone a perfect vortex destroying SSW whilst the Siberian daughter has been left intact. Timings and dates were perfect in pre winter forecast - just that you can't end up forecasting that - lol! And it is worth laughing about because as this week shows there are far worse thing in life to get upset about!

Edited January 10, 2015 by chionomaniac

[lorenzo]

Precisely, no one could have forecast that, anyone claiming to be able to model a post wave 2 split dynamic is is lala land. In honour of our old winter vortex foe I am going to not get this lovely t-shirt on..

[chionomaniac]

Precisely, no one could have forecast that, anyone claiming to be able to model a post wave 2 split dynamic is is lala land. In honour of our old winter vortex foe I am going to not get this lovely t-shirt on..

Vortex T.jpeg

Is there a chilli on the back?

 

Watch the 20hPa level on the below animation. Perfectly illustrates the destruction of the Canadian vortex whilst the Siberian just takes control.

 

http://www.pa.op.dlr.de/arctic/ecmwf.php?im=1

Edited January 10, 2015 by chionomaniac

[Recretos]

I still don't understand why this 8 januari warming hasn't reversed the 10 hpa wind. It has been quite a substantial warming and leaves behind a very disturbed temperature pattern. Yet it creates only a relatively small change in de stratospheric windfield. 

 

warming.JPGWarming 3.JPG

 

Perhaps it is due to the exteme low tropospheric heights below the warming region or are there any other causes?

 

Warming 2.JPG

Wind is bound to the pressure gradient force (among some other stuff, but thats besides the point at the moment).

And that brings me to a specific point. I am on here for the third season, and even tho I am trying to make this specific point every year (and one page back actually ), some still dont get it.

Write it down, print it, and put it on the fridge or a wall, as long as you see it enough times to remember it:

"Winds reflect the geopotential height pattern, NOT the temperature pattern."

Enough said

[Skin]

Meanwhile, the US is getting bombarded with brutal cold air. I suspect this warming in the stratosphere and split PVs played a higher role than most realize.

[Paul123]

Thank you guys, for your comments, it pretty much makes clear to me why the temperature regime poorly reflected the geopotential height pattern. 

[polar vortex]

Meanwhile, the US is getting bombarded with brutal cold air. I suspect this warming in the stratosphere and split PVs played a higher role than most realize.

Short term yes, longer term it is Europe and the UK that will benefit the most. Major northerly blocking to 

come.

[karyo]

Short term yes, longer term it is Europe and the UK that will benefit the most. Major northerly blocking to 

come.

You sound confident about it...

[Woollymummy]

Being a Polar Vortex, he would be the best person to know what is happening up there, great name and nice to have a visit from such an influential phenomenon :-)

[Woollymummy]

So the two sketches, I am trying to visualise it, with a single vortex the wind is air falling towards the centre low , dense, thin bit in the middle, and when the vortex is split it makes a thick warmer hump in the middle, and the air rolls downhill on either side to the respective vortex so we are hoping or expecting to get some air out of the disturbed bit in the middle? UK is the splatted bit at the bottom of the second picture. Is this right or muddled?

Edited January 10, 2015 by Woollymummy

[Crocodile23]

Wind is bound to the pressure gradient force (among some other stuff, but thats besides the point at the moment).

And that brings me to a specific point. I am on here for the third season, and even tho I am trying to make this specific point every year (and one page back actually ), some still dont get it.

Write it down, print it, and put it on the fridge or a wall, as long as you see it enough times to remember it:

"Winds reflect the geopotential height pattern, NOT the temperature pattern."

 

Sure, on a first level, but on a deeper level, ultimately, everything are being driven by temperature(temperature gradients).

 

Edited January 10, 2015 by Crocodile23

[chionomaniac]

Sure, on a first level, but on a deeper level, ultimately, everything are being driven by temperature(temperature gradients).

 

Yes, but the temperature gradients alone won't show you what the vortex is doing - the chart Paul originally posted highlights why Andrej is correct to emphasise why looking at the whole picture is so important.

[Paul123]

Wind is bound to the pressure gradient force (among some other stuff, but thats besides the point at the moment).

And that brings me to a specific point. I am on here for the third season, and even tho I am trying to make this specific point every year (and one page back actually ), some still dont get it.

Write it down, print it, and put it on the fridge or a wall, as long as you see it enough times to remember it:

"Winds reflect the geopotential height pattern, NOT the temperature pattern."

Enough said

 

This is not the point.

 

I am still left with the question whether the geopotential height pattern in the troposphere affects the height of the geo's in the stratosphere. It sometimes does, so it seems to me. If (purely hypothetically) over a large area there would be created a vacuum, the pressure would drop. The geo's above this area would be pulled down, as is in a minor way for instance the case with a tropical cyclone or tornado.

Analoguely in the 8 januari case the cold reservoir above northern Canada and Greenland and the associated vast tropospheric low pressure area may have hindered the rising of the stratospheric geo's, thus the forming of a SSW.  In some cases, the tropospheric pressure pattern, might hinder the emergence of a ssw , if not prevent it completely. That's my thesis.

Edited January 11, 2015 by Paul123

[Interitus]

 

Interitus mentioned 3 examples above. 2012, 1986 and 1991. 

 

Lets have a look, shall we.

 

 

 

An excellent review though one which highlights the difference between looking at these events in synoptic detail compared to general climatology composites which is the case in much of the research.

 

The geopotential anomaly timeseries charts for 1991 and 2012 are actually very similar with stratosphere anomalies preceding those near the surface.

Examining the periods from 10 days before to 30 days after the notional central dates of minimum stratosphere NAM of 28/1/1991 and 17/1/2012 (from Martineau) further shows these similarities. Firstly, the MERRA 60°N wind profiles show reductions at each level in the days preceding the central dates (day 0 on x-axis), followed by periods of negative vertical wind shear -

 

1991

 

2012

 

The effects are then seen at the surface, with AO falling negative after the central date

 

 

Interestingly, there appears to be a correlation (in these two cases at least) between the 10mb wind and AO of about 0.65 with a lag in AO of two or three days.

 

The NAO shows remarkable similarity of trend and amplitude

 

 

When viewed in a broader sense, it's possible these two examples appear to be showing essentially the same kind of event.

 

Now 1986 is slightly puzzling and I would be inclined to agree that stratospheric influence is tenuous. There are warmings and wind speed reductions in the dataset but nothing at a glance that particularly stands out and maybe as a result it doesn't feature in most reanalysis SSW lists.

However, the date 3/1/1986 (before the start of the video) was identified by Mitchell et al. (2013) in The Influence of Stratospheric Vortex Displacements and Splits on Surface Climate - http://www.physics.ox.ac.uk/Users/mitchell/mitchell2013_jclim.pdf

 

In this paper they identify weak vortex events using elliptical diagnostics to describe the distribution of potential vorticity, and they contrast this to the typical zonal mean zonal wind metrics and the number of newly identified events. In one respect this brings them closer to the more synoptic level examination of the asymmetry of the vortex not constrained by the concentric zonal descriptions. Then on the other hand the work returns to general climatology composites.

The discussion considers effects of tropopause height change through vorticity inversion and the descent of NAM anomalies, and the surface pressure and temperature patterns to 60 days after the event. This brings Feb 1986 into the results, clearly not including an event of this magnitude (eg monthly AO -2.904) would have some effect on the results. Good work Recretos!

Edited January 11, 2015 by Interitus

[feb1991blizzard]

Is there any light at the end of the tunnel for feb or are we really staring down the barrel for getting any significant warmings in February, its not looking too crash hot to me right now.

[Vorticity0123]

For anybody who is interested in the background of the Eliassen-Palm flux, I've made a post describing the fundamentals and a brief physical interpretation of the flux. It can be found here:

 

https://forum.netweather.tv/topic/82250-the-eliassen-palm-flux/

Edited January 11, 2015 by Vorticity0123

[karyo]

Is there any light at the end of the tunnel for feb or are we really staring down the barrel for getting any significant warmings in February, its not looking too crash hot to me right now.

I have seen more posts about what happened so far (or what went wrong) than posting for the near future so I guess people have given up hope.

[feb1991blizzard]

I have seen more posts about what happened so far (or what went wrong) than posting for the near future so I guess people have given up hope.

 

The top - middle  strat looks like it will be cooling now so the best we can hope for between now and the first third of Feb in my opinion is that some sort of 2 wave trop pattern can at least stave of any downwelling of the re strengthening vortex up top and buy us some more time and have another go later on, Glory A of course would be a load of sliders followed by the end of GFS(p) FI and we get the scandi high first time around (outsider of course).

 

EDIT : first day for ages today that I never even looked at the Berlin charts, I as nothing posted here then I guess they didn't take your breath away!

Edited January 12, 2015 by feb1991blizzard

[Skin]

Got some information straight from NOAA and AMS regarding the current strat situation. Basically just reiterating what we already know, NOT a major SSW and will try to classify as a Minor SSW.

 

Today's Topics:

   1. Re: Wave-2 stratospheric warming to usher in the New      Year!
      (Amy Butler - NOAA Affiliate)


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Message: 1
Date: Fri, 9 Jan 2015 12:32:30 -0700
From: Amy Butler - NOAA Affiliate <amy.butler@noaa.gov>
To: strat_list@nwra.com
Subject: Re: [strat_list] Wave-2 stratospheric warming to usher in the
        New     Year!
Message-ID:
        <CAEPbyeM5sdsZdCoXe0cT+dTn0=2+F9RNwVEPjW4KdjCV=w5q=A@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

Thanks, Paul.

As we have been discussing this last week at the AMS meeting, while the
vortex did split and the temperature gradient reversed over the polar cap,
a reversal of the zonal circulation did not occur at the 10 hPa level
anywhere equatorward of 70N, so this event will not be classified as a
major event by the current criteria at 10 hPa and 60N.

We'll also use this opportunity as a plug for our current efforts
associated with SPARC in updating the standard SSW definition.  Some of
these efforts include defining minor warmings such as this one more
clearly.  More information can be found at our new email list (subscribe on
the left hand side): https://sites.google.com/site/stratosphericwarmings/

We had an interesting group discussion at AMS and will have at least one
other at the EGU General Assembly this spring in Vienna (possibly also at
IUGG and/or AOGS) and hope to see you all at one of these gatherings.

Cheers,

Amy Butler
Ed Gerber
Dann Mitchell

------------------------------
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Message: 1
Date: Tue, 30 Dec 2014 14:52:53 -0500
From: "Paul A. Newman" <Paul.A.Newman@nasa.gov>
To: <strat_list@nwra.com>
Subject: [strat_list] Wave-2 stratospheric warming to usher in the New
        Year!
Message-ID: <A47F2125-B25B-4DAF-8FA6-E5FB0E261BE0@nasa.gov>
Content-Type: text/plain; charset="windows-1252"

Hey All,

There is a wave-2 warming that is developing. Should be maximizing around
Jan. 3.

See http://acdb-ext.gsfc.nasa.gov/Data_services/arctic/  for maps.

Yours, Paul

Dr. Paul A. Newman
Code 610.0 NASA/GSFC Greenbelt, MD 20771
ph: (301) 614-5985 fx: x-5903
http://acdb-ext.gsfc.nasa.gov/People/Newman/
?The race may not always be to the swift nor the victory to the strong, but
that's how you bet? - D. Runyon

[Skin]

https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxzdHJhdG9zcGhlcmljd2FybWluZ3N8Z3g6NzM1ODZjYjIxMWE4ZTgyOA

 

Table 2, has 7 different SSW definitions. Look at how unsure we are about what constitutes as a SSW. Hopefully the WMO will get the point we need a set one definition. whatever it is. From this paper. 

 

https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxzdHJhdG9zcGhlcmljd2FybWluZ3N8Z3g6MjJkZmUzY2M3ZmVkYjhhMA