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Stratosphere Temperature Watch 2012/2013


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Talking about lag-times: on the basis of what is written in this thread it is clear to me that there is a lag time between the occurrence of a SSW and the stratosferical vortex response (displacement, split etc.).

But I am still struggling with the lag time between stratosferical vortex changes and the troposferical effects they have. I understand that there are a lot of processes involved (coupling is discussed in this thread) there but there must be a lag.

It looks to me that the current restoration of the stratosferical vortex almost instantaneously has an effect on the enormous troposferical W-E transport of LP-energy across the Atlantic. It might be a coincidence with historical stratosferical events but I would like to understand this.

Another question: Do (and to what extent) the weather-models take the physical interaction (including SSW's) between stratosphere and troposphere active into the modelling account or are they purely based on historical data?

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Steve whilst I agree to a certain extent, more especially with regards to the difficulty in forecasting exact placement of tropospheric synoptics (particularly with regard to the UK in the overall sch

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Actually Piers has been nearer the mark this winter than many of our so called experts on here, it appears Piers is easy to make fun off here, but his record is as good as anyones here, sure he gets it wrong at times but look at the Net weather winter forecast, busted in December.

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Yeah, but even a broken clock is right twice a day.

As Chio rightly states: it's not even so much about whether he's 'right' or 'wrong' - it's the gibberish which he wraps around his sage prophecies which is just plain garbage. He shows himself up to be a complete and utter charlatan, as he doesn't even understand the basic elements of the science of which he claims to be expert witness of.

Commercially minded venture though, so very easy to understand his business model; The Sun doesn't have to be correct, it just needs to grab enough dullards attention.

Edited by SnowBallz
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Just to add a caveat to the above mean CET anomaly values and emphasise the variability in the data...here are graphs for displacements and splits with the upper and lower quartiles of the CET anomalies plotted for each day.

The interquartile range has a tendency to increase every time there is is a strongly negative CET anomaly. This might indicate that the mean is being forced down at these points by just a few of the events, so while there could be strongly negative values at these points, it is by no means a certainty.

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The SWW has along with wave activity split the vortex , agreed.

But the Canadian vortex has spoilt the fun this year , spilling too much energy into the Atlantic .

But baring in mind the SSW promotes high lat blocking ,

I think there's some confusion with regards to cause and effect. SSW seems, with the evidence we have available, to weaken the Polar Vortex. This then leads to an increased probability of Northern Blocking. SSW in itself does not promote northern blocking because even with a split vortex we may still find the situation is not conducive.

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I think there's some confusion with regards to cause and effect. SSW seems, with the evidence we have available, to weaken the Polar Vortex. This then leads to an increased probability of Northern Blocking. SSW in itself does not promote northern blocking because even with a split vortex we may still find the situation is not conducive.

No confusion on my part white fox , maybe a wrong word choice by me, but no confusion,

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Good work 03jtrickey, mirrors some of the stuff I've been doing. Regarding the 0-day I had been going off 7th but actually might've been 6th - 10mb vortex split then, didn't check the zonal wind but think there were some showing 6th.

You could extend your work using the examples by Martineau, who has updated his animations with temperatures as well as zonal winds, and includes the current SSW as it has progressed. Think in most cases it is clear which are splits or displacements, but the dates aren't the start date but the minimum NAM which tends to be a few days later - with this year the 17th being quite a big gap - http://curriculum.pm...ssw-animations/

Regarding CET correlations with NAO and AO, it turns out that possibly neither of these indices may be always well suited. Sometimes one or the other or both correlate very well, other times not at all, and this is using the standard CPC 20-90°N as well as the 35-65°N indices by Li - http://ljp.lasg.ac.cn/dct/page/65544 and the 40-90°N SV NAM by Ogi, Yamazaki & Tachibana - http://wwwoa.ees.hok...-NAM/index.html

As can be seen in the charts here for example http://ljp.lasg.ac.cn/dct/page/65607 the UK tends to lie in the zone where there is low correlation between the indices and SLP.

Edited by Interitus
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No confusion on my part white fox , maybe a wrong word choice by me, but no confusion,

Maybe I should state what I mean in these terms (bearing in mind of course that our understanding of the effects of SSW on the troposphere is in its infancy)

SSW > Disrupted Polar Vortex > Increased probability of Northern Blocking

SSW in itself does not, IMHO, promote northern blocking. What it does is disrupt the PV which allows gaps to form which may allow northern blocking to become established. However, the actual location of Northern blocking, if any, is dependent on where the remnants of the PV remain.

In summary, SSW does not promote high latitiude blocking. The split vortex does, but does not provide a guarantee.

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Great work!

Mean CET anomalies are relatively lower in days 60-30 prior to splits compared to displacements.

Logically there would be a very good reason for this too. The split type SSW is driven by Wave 2 activity, which tropospherically is driven by a Scandi/Siberian/Sceuro HP (basically an HP with western periphery located somewhere close to the North Sea). As we saw in Late November/Early December (approx 30-45 days before the surge in Wave 2 Activity which has helped to drive the split in the PV this time - though admittedly this SSW has been unique in nature given the concurrent displacement and split), this generally leaves the UK either in or on the periphery of some rather cold air.

Good to see some statistical proof of this :)

SK

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Any more experienced people with SSW on here? As we are supposed to see effects 14-28 days later could we see a dramatic weakening of the PV around Greenland that is not currently being predicted? And have we seen a trophospheric response yet? Because when you look at the PV before the SSW came it was pretty damn weak anyway so I'm wondering what further effects it should have?

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Actually Piers has been nearer the mark this winter than many of our so called experts on here, it appears Piers is easy to make fun off here, but his record is as good as anyones here, sure he gets it wrong at times but look at the Net weather winter forecast, busted in December.

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Well on here we don't try to make money out of it and many are doing it simply for fun. If you cast your net wide enough and then move actual events into your date line you're going to be always right. Most of the time he's simply wrong and just occasionally gets lucky.

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Another thing 03jtrickey, did you try adding a lag time between NAO/AO and CET? I found that the CET maximum correlation on average to be 2 days after NAO/AO.

Good point - I will add that to my list of things to test out. Thanks Posted Image

As I went to test that suggestion out I noticed a mistake in my AO/NAO/CET correlations (I'll blame it on copying formulas in Excel late at night). The updated values are as follows and affect the correlations between the CET and AO 60 days after displacement:

Posted Image

Using these corrected values, the correlation between CET and AO increases for both displacements and split vortex events after SSW onset, and in both cases the AO is more strongly correlated with CET than the NAO after onset. Sorry about that.

Edited by 03jtrickey
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Maybe I should state what I mean in these terms (bearing in mind of course that our understanding of the effects of SSW on the troposphere is in its infancy)

SSW > Disrupted Polar Vortex > Increased probability of Northern Blocking

SSW in itself does not, IMHO, promote northern blocking. What it does is disrupt the PV which allows gaps to form which may allow northern blocking to become established. However, the actual location of Northern blocking, if any, is dependent on where the remnants of the PV remain.

In summary, SSW does not promote high latitiude blocking. The split vortex does, but does not provide a guarantee.

Well surely if a SSW allows high lat blocking in the "gaps" as you say, then a SSW does promote high lat blocking in the Northern Hemisphere (cause and effect) it's where that blocking sets up that is important to our little patch though.

The recent quick response to the SSW just about allowed some blocking in the gap and that produced a very snowy spell for many (and two weeks below average temps) we did not see substantial blocking on our side of the globe but just enough to deliver the goods.

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Talking about lag-times: on the basis of what is written in this thread it is clear to me that there is a lag time between the occurrence of a SSW and the stratosferical vortex response (displacement, split etc.).

But I am still struggling with the lag time between stratosferical vortex changes and the troposferical effects they have. I understand that there are a lot of processes involved (coupling is discussed in this thread) there but there must be a lag.

It looks to me that the current restoration of the stratosferical vortex almost instantaneously has an effect on the enormous troposferical W-E transport of LP-energy across the Atlantic. It might be a coincidence with historical stratosferical events but I would like to understand this.

Another question: Do (and to what extent) the weather-models take the physical interaction (including SSW's) between stratosphere and troposphere active into the modelling account or are they purely based on historical data?

Any thoughts on these questions?

I know Chio mentioned that the troposferical vortex above Canada is getting disconnected from the stratosferical one but the amount of energie this is moving across the atlantic currently appears to me as a strong troposferical polar Vortex. The 500 Hpa models show that HP intermittently tries to move north but is continously "ironed" away in the coming days/weeks.

I am still very much trying to understand whether and how this troposferical condition relates to previous stratosferical events.

My question about the models is related to that: maybe they dont model/calculate those coupling processes at all... Then I know what the value of model-predictions is.

Edited by skatefan
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Any thoughts on these questions?

I know Chio mentioned that the troposferical vortex above Canada is getting disconnected from the stratosferical one but the amount of energie this is moving across the atlantic currently appears to me as a strong troposferical polar Vortex. The 500 Hpa models show that HP intermittently tries to move north but is continously "ironed" away in the coming days/weeks.

I am still very much trying to understand whether and how this troposferical condition relates to previous stratosferical events.

My question about the models is related to that: maybe they dont model/calculate those coupling processes at all... Then I know what the value of model-predictions is.

Lol, just look at physics, for example, the Young-Laplace equation..if theres only one variable with an error..the value is probably basicly 0

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though admittedly this SSW has been unique in nature given the concurrent displacement and split

Not sure that this is the case, January 2010 was a displacement followed by a split as can be seen in the animation http://curriculum.pm.../2010_01_30.gif

Comparing reanalysis of the current event with the precursors by Cohen & Jones http://web.mit.edu/~...dJones_JC12.pdf tends to suggest that it would've been a displacement, and with regards to Jan 2010 they class as a split. However Dornbrack et al. http://www.atmos-che...2-3659-2012.pdf happily class Jan 2010 as a displacement. Although it's tempting to class things in black and white it seems as usual to be more complex than that, and there is some mileage in Chio's point about taking each SSW on its own merits.

Edited by Interitus
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I have not properly perused here for a while and I was hoping for someont to[in laymans terms] to explain what is going on in the upper stratosphere in relation to the troposhere and obviously it downwelling and effect on the it in relation to northern hemespherical weather especially in regards to Cold weather in our parts of the northern hemesphere?Thankyou in advance to any replies .ta ta

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Hi everyone. I see the topic is still very active, which is really awesome. I apologise for my lack of posts, but I am really busy with some side projects, which basically takes my time away from all forums. And besides that, I don't really post unless I have something worth posting. Posted Image

Just wanted to say, that during the year, in my free time I have a plan to make fresh MJO climatologies (basically anomaly reanalyses) for different phases. I think I am getting quite good with reanalysis and I have found some MJO archives for the entire 1980-2012 period, from many different sources, which should be enough to make a basic phase climatology. Basically I would do this to kinda test my reanalysis skills. Posted Image (But as far as it looks, no real skills are needed Posted Image, mainly time)

Now there is something to consider:

1) The before mentioned time lag. I was planing to use only last two days of a certain phase, with the condition that the phase must be "active" for at least 6 consecutive days, so I would use only the really "influential" phases.

2) The different strength of certain phases. Sometimes a certain phase in a certain month in a certain year, is weaker/stronger than in a different time. So putting it all in one mix would give us a certain mean value or "mean anomaly", but the respected deviation would probably be quite high.

3) I had 3 point, but I forgot what the 3rd point was. Will add it later if I remember.

So the main difficulty is of course the collection of dates. Once I have all the dates for the phases, the main work is basically done, and I can start playing around. From there on, I can divide it into specific ENSO years, SSW years, QBO years, different combinations, etc,... I could make specific maps for N. Hem, Europe, etc... Different parameters like T2m, H500, U-Wind, etc...

I have in plan to make a dates-datafile for each phase in a specific format, so I can upload it to the NOAA FTP servers, and use it as a custom time-series for reanalysing. Basically then the options are almost endless, because I always just use the uploaded file, instead of writing the dates every time into the reanalysis interface. And not to mention, that the daily reanalysis interface supports only 20 custom dates, while I can put 1000 dates into the custom datafile. And from there on, it is basically like a normal reanalysis, but with the MJO phase specific dates.

So, this is quite a huge project for me, given the fact that I have in general quite a busy schedule, but I hope I will complete it before the new winter season. Posted Image I think it could be done in a month, but it would take some serious time dedication. Posted Image

Any suggestions before I start?

Best regards.

An ambitious plan!

The Australian BOM MJO daily data runs slightly longer, from June 1974 to the present day http://www.bom.gov.a...4toRealtime.txt

The only problem you might have is getting many samples of each type to compare to show true averages and correlations.

For example I used above average amplitude (about 1.27) MJO phase 7 days with a neutral MEI (between ~ -0.6 to 0.6) from separate years to avoid autocorrelation. The aim was to look at current conditions today as close as possible but there were hardly any comparable days, so it had to be much more generalised to get the 11 days on the composite. Even then a couple of the periods selected only had one day in January with the rest in December or February.

The result was interesting because I expected to see no pattern, but with the 10-day lag, lo and behold a -NAO signature emerged as suggested by Cassou.

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Hi Recretos.

That is a great idea and as Interitus suggests also very ambitious. I am really busy at work and hence my lack of posts but after winter if I get any free time I will be assist if possible( maybe with research). I really think that this is something we need - but wonder should you be looking at the GWO rather than the MJO to get a fuller picture?

Anyway good luck.

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@Interitus: Thanks for the suggestion and the link to the archive. Posted Image .

I really have to develop a "fixated" methodology before I start. I was thinking of using phases with amplitude above 0.85. And for the ENSO years separation, the neutral period being MEI from 0.5 to -0.5. Everything below of above, counting as a La Nina or El Nino year, respectfully. I am also thinking of using the ONI index for ENSO phase determination, but it is seasonally averaged.

And about the lag. I am planing to use a number of days that will depend on the longevity of the phase. More long lasting the phase, more days I will take out. But of course not all. And the main goal will first be to extract the exact phase days. I can apply lag later when I begin the reanalysis process.

@Chiono:

The research area would sure need someone knowledgeable. Posted Image I can do the basic climatologies and everything, but that will have to be "verified" and put into practical use.

And about the GWO: I was actually thinking of that, but to be honest, those composites would have far less forecasting usefulness than the MJO, which phases and movement is actually being forecasted. So having climatologies for a certain forcing which is being forecasted, would be more meaningful, at least in my view. Posted Image

I am a bit worried about the deviation about the actual response within each phase, We all know the "system" is more complicated and with more forcings than just the MJO, so the outcome is not always the same. But the current climatologies at http://raleighwx.ame...wx.com/MJO.html have been quite useful as a guidance or a display of tendency, so that gives me some confidence.

Just one thing to consider: If I actually manage to make these climatologies, it would probably be quite a few graphics. And I dont really have a way to host these graphics. And just keeping them on my computer is basically nonsense. So I would like to know if there would be a way that these graphics would be hosted here on Netweather, having a page of their own? Of course I have to make the graphics first, but I have to ask in advance. Posted Image Basically the only really useful climatologies are the ones on the http://raleighwx.ame...wx.com/MJO.html site. So Netweather would basically then be the only site to have updated climatologies, with Europe maps, and different parameters. Just for consideration. Posted Image

Best regards.

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@Interitus: Thanks for the suggestion and the link to the archive. Posted Image .

I really have to develop a "fixated" methodology before I start. I was thinking of using phases with amplitude above 0.85. And for the ENSO years separation, the neutral period being MEI from 0.5 to -0.5. Everything below of above, counting as a La Nina or El Nino year, respectfully. I am also thinking of using the ONI index for ENSO phase determination, but it is seasonally averaged.

And about the lag. I am planing to use a number of days that will depend on the longevity of the phase. More long lasting the phase, more days I will take out. But of course not all. And the main goal will first be to extract the exact phase days. I can apply lag later when I begin the reanalysis process.

@Chiono:

The research area would sure need someone knowledgeable. Posted Image I can do the basic climatologies and everything, but that will have to be "verified" and put into practical use.

And about the GWO: I was actually thinking of that, but to be honest, those composites would have far less forecasting usefulness than the MJO, which phases and movement is actually being forecasted. So having climatologies for a certain forcing which is being forecasted, would be more meaningful, at least in my view. Posted Image

I am a bit worried about the deviation about the actual response within each phase, We all know the "system" is more complicated and with more forcings than just the MJO, so the outcome is not always the same. But the current climatologies at http://raleighwx.ame...wx.com/MJO.html have been quite useful as a guidance or a display of tendency, so that gives me some confidence.

Just one thing to consider: If I actually manage to make these climatologies, it would probably be quite a few graphics. And I dont really have a way to host these graphics. And just keeping them on my computer is basically nonsense. So I would like to know if there would be a way that these graphics would be hosted here on Netweather, having a page of their own? Of course I have to make the graphics first, but I have to ask in advance. Posted Image Basically the only really useful climatologies are the ones on the http://raleighwx.ame...wx.com/MJO.html site. So Netweather would basically then be the only site to have updated climatologies, with Europe maps, and different parameters. Just for consideration. Posted Image

Best regards.

Recretos

Hopefully netweather might be able to sort this out, but if not then let me know and I'm happy to store them online and create a viewing platform for them - I might even be able to create a website dedicated to it

SK

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