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Here is my understanding of the PV:

As we head towards Winter the differences in temperatures at lower and higher latitudes create a vortex in the stratosphere and troposphere around the Arctic regions. Differences in temperatures in the stratosphere over the Arctic due to several factors (eg Rossby waves) can cause changes in the Stratospheric Polar Vortex which then feed down to the Tropospheric Polar Vortex. These changes can affect weather patterns at sea level. Dramatic changes caused by events such as SSW's can cause the PV to split or displace, which will have massive effects on weather patterns. But how? For example, does a PV that is displaced over Greenland cause high pressure to build here? Or does it do the complete opposite?

Basically, my question is; in what way does the positioning of a split/ displaced PV affect weather patterns such as pressure systems, zonal/ meridonial winds, etc?

I appreciate this may get a bit technical (for me at least!), but I will try my best to understand.

Any answers would be much appreciated.

Many thanks.

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Your suggestions are totally true. Yes, the displacement of the polar vortex very well describes these Rossby waves and the dynamics of the mid-latitude atmosphere. The bigger the amplitude is, the larger the blocking circulation patterns become. If the PV is more displaced this limits the zonal prevailing flow and gives way to a more polarward-oriented one. If we have e blocking pattern, cold spells are more likely to occur at low latitudes and vice versa. If the PV is strong and concentrated: we have a north-south split of the weather. There are weak troughs producing weak surface lows travelling fast from west to east.

One very important application of the stratospheric vortex is its role in ozone depletion. It takes place basically on the South pole where the air is stuck and the chemical reactions leading to the process of ozone depletion are very easily carried out.

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Here is my understanding of the PV:

As we head towards Winter the differences in temperatures at lower and higher latitudes create a vortex in the stratosphere and troposphere around the Arctic regions. Differences in temperatures in the stratosphere over the Arctic due to several factors (eg Rossby waves) can cause changes in the Stratospheric Polar Vortex which then feed down to the Tropospheric Polar Vortex. These changes can affect weather patterns at sea level. Dramatic changes caused by events such as SSW's can cause the PV to split or displace, which will have massive effects on weather patterns. But how? For example, does a PV that is displaced over Greenland cause high pressure to build here? Or does it do the complete opposite?

Basically, my question is; in what way does the positioning of a split/ displaced PV affect weather patterns such as pressure systems, zonal/ meridonial winds, etc?

I appreciate this may get a bit technical (for me at least!), but I will try my best to understand.

Any answers would be much appreciated.

Many thanks.

Hi 22nov2010blast,

I think that your question highlights an area of uncertainty that we would like to be able to predict better.

We can be pretty sure that a very cold stratosphere will override high latitude blocking signals and a strong polar vortex and increased westerly flow will be prevalent. The position of mid latitude blocking in these set ups can be more difficult to predict and Rossby waves tend to be of a lesser amplitude. Predicting the actual positioning of mid latitude blocks in winter is difficult, but there are clues in the overall atmospheric state that can be used to assist. This is where analysing the global atmospheric angular momentum and MJO can help. Aligning these to the current ENSO state can give us an idea of where the more likely hemispheric trough and ridge positions are likely to set up. This is not an exact science but the more knowledge gained in these areas, the better the understanding of where ridges and troughs are more likely to position. Just by using previous H500 analogues from the GWO and MJO we can gain a fair amount of insight that any positioning is not a chance eveNT.

If we have a warmer polar stratosphere over winter then the same principles apply, however, with increased Rossby wave amplitude, the positioning of any blocking is likely to be further north, which in itself can feed back into the stratosphere and create further polar vortex weakening.

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Thanks guys, this information is really helpful and I much appreciate the explanations. It's a little technical for me at the moment but I'm sure I'll get to understand it soon enough.

Once again, many thanks.

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Thanks guys, this information is really helpful and I much appreciate the explanations. It's a little technical for me at the moment but I'm sure I'll get to understand it soon enough.

Once again, many thanks.

Following Chiono`s excellent post you may find the Wikipedia link here a good read as well

http://en.wikipedia.org/wiki/Polar_vortex

It explains things reasonably straightforwardly i mo-also look out for the reopening of his Strato.thread later in the Autumn.

Regards,Phil. .

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Following Chiono`s excellent post you may find the Wikipedia link here a good read as well

http://en.wikipedia.org/wiki/Polar_vortex

It explains things reasonably straightforwardly i mo-also look out for the reopening of his Strato.thread later in the Autumn.

Regards,Phil. .

Thanks for the link, will read over it, I didn't realise there was a Wikipedia page on it!

I actually followed the thread last year but I was a novice back then and didn't understand most of it! Should have a much better understanding this time round.

Again, many thanks.

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