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Bring Back1962-63

​​​​​​​LEARNING ABOUT TELECONNECTION SCIENCE AND BACKGROUND SIGNALS

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I've wanted to post in this thread for a while, but have been sidetracked by the actual weather following the SSW, but with the current rain, drizzle and generally rubbish weather, I'm taking a break from the MOD!  I think this thread is excellent and look forward to following it avidly.  
I've tried to read up on teleconnections, particularly the GWO and AAM, but feel there are still some major gaps in my understanding that maybe you folks could help with.  So two questions for today:
1. The phrase 'seasonal wavelength changes' is one I've seen regularly in posts relating to teleconnections.  I'm unsure what this means, although I assume it relates to the meandering of the jet stream in some way. So could anyone please provide an explanation of:  the wavelength of what is changing, how does it change, why does it change, and how might that impact the UK at various times of year?
2. A lot of discussion I've read has been related to winter.  I'd like to know what teleconnections can tell us about summer, I know the strat is out of play, but what can give an indication of summer weather patterns a few weeks in advance?
Thanks in advance and very best regards.
Mike

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I just wanted to say that I have recently taken on some additional business commitments which will take up the small amount of free time that I have available for an extended period. I will now only be able to post very occasionally and perhaps not at all during the next few months. Needless to say, I will not have any time to develop this learning thread as I had wished to. I apologise to anyone who was expecting to see greater activity on here. I hope that others will continue to contribute to and support this thread with questions and answers. Perhaps someone might like to respond to @Mike Poole and his queries in the post just above this message. This is exactly what this thread is intended for.

David. 

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4 minutes ago, Bring Back1962-63 said:

I just wanted to say that I have recently taken on some additional business commitments which will take up the small amount of free time that I have available for an extended period. I will now only be able to post very occasionally and perhaps not at all during the next few months. Needless to say, I will not have any time to develop this learning thread as I had wished to. I apologise to anyone who was expecting to see greater activity on here. I hope that others will continue to contribute to and support this thread with questions and answers. Perhaps someone might like to respond to @Mike Poole and his queries in the post just above this message. This is exactly what this thread is intended for.

David. 

Good luck with these extra commitments :) 

I will attempt to do the occasional post, though as with you my time will be constrained when back studying next week. I will hopefully formulate a response to Mike in the upcoming days :) .

On a separate note, I will be transferring across a detailed update to the 'Hurricane Tutorial' written back in 2005 in preparation for the upcoming North Atlantic Hurricane Season. It should be fully updated and available on here within two weeks, anyone interested should occasionally check in the Hurricane Tutorial thread and possibly any new thread for the upcoming season where it will likely be added to. 

  

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On 4/3/2018 at 20:16, Mike Poole said:

I've wanted to post in this thread for a while, but have been sidetracked by the actual weather following the SSW, but with the current rain, drizzle and generally rubbish weather, I'm taking a break from the MOD!  I think this thread is excellent and look forward to following it avidly.  
I've tried to read up on teleconnections, particularly the GWO and AAM, but feel there are still some major gaps in my understanding that maybe you folks could help with.  So two questions for today:
1. The phrase 'seasonal wavelength changes' is one I've seen regularly in posts relating to teleconnections.  I'm unsure what this means, although I assume it relates to the meandering of the jet stream in some way. So could anyone please provide an explanation of:  the wavelength of what is changing, how does it change, why does it change, and how might that impact the UK at various times of year?
2. A lot of discussion I've read has been related to winter.  I'd like to know what teleconnections can tell us about summer, I know the strat is out of play, but what can give an indication of summer weather patterns a few weeks in advance?
Thanks in advance and very best regards.
Mike

Good Evening Mike :)  ,

Seasonal Wavelength Change : With regard to the notion of teleconnections, this relates (as you mentioned) to jet stream undulation/amplitude.  Winter is characterized through a high poleward temperature gradient, resulting in increased upper atmospheric zonal winds (Jet Stream). High velocity upper atmospheric winds rarely reflect themselves in a meridional (high amplitude) setup, partial reasoning at least why winter weather is dominated by interchangeable surface setups (Unsettled). In summer months, with the considerable weakening of the polar vortex the temperature gradient is far less pronounced, resulting in lower upper atmospheric zonal winds (Jet Stream). This can and usually translates to a more amplified pattern being seen in the upper winds. In short, summer is characterized by short wavelength (increased amplitude) jet stream (Slower Aswell) setups and this is reversed in winter months. 

A possible approach to this (for beginners), is to consider why blocked surface patterns gain so much interest in the winter period. It will have weak correlation with fanatical hopes of snowmageddon, but on a serious note it provides respite from the broad continuum of strongly zonal conditions. Wavelength changes can change more abruptly on reduced timescales, these being induced by changes in the global wind oscillation (GWO), MJO phases etc. 

An interesting line of thought, especially since the turn of the millennium regards an ever increasingly undulated jet stream in both winter & summer potentially related to arctic temperature sensitivity. Here are a few links to research papers for you : 

https://ams.confex.com/ams/94Annual/webprogram/.../Extended Abstract.pdf

http://iopscience.iop.org/article/10.1088/1748-9326/10/1/014005/pdf

Feel free to message me with any specific queries :) 

 

 

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22 hours ago, MattTarrant said:

Good Evening Mike :)  ,

Seasonal Wavelength Change : With regard to the notion of teleconnections, this relates (as you mentioned) to jet stream undulation/amplitude.  Winter is characterized through a high poleward temperature gradient, resulting in increased upper atmospheric zonal winds (Jet Stream). High velocity upper atmospheric winds rarely reflect themselves in a meridional (high amplitude) setup, partial reasoning at least why winter weather is dominated by interchangeable surface setups (Unsettled). In summer months, with the considerable weakening of the polar vortex the temperature gradient is far less pronounced, resulting in lower upper atmospheric zonal winds (Jet Stream). This can and usually translates to a more amplified pattern being seen in the upper winds. In short, summer is characterized by short wavelength (increased amplitude) jet stream (Slower Aswell) setups and this is reversed in winter months. 

A possible approach to this (for beginners), is to consider why blocked surface patterns gain so much interest in the winter period. It will have weak correlation with fanatical hopes of snowmageddon, but on a serious note it provides respite from the broad continuum of strongly zonal conditions. Wavelength changes can change more abruptly on reduced timescales, these being induced by changes in the global wind oscillation (GWO), MJO phases etc. 

An interesting line of thought, especially since the turn of the millennium regards an ever increasingly undulated jet stream in both winter & summer potentially related to arctic temperature sensitivity. Here are a few links to research papers for you : 

https://ams.confex.com/ams/94Annual/webprogram/.../Extended Abstract.pdf

http://iopscience.iop.org/article/10.1088/1748-9326/10/1/014005/pdf

Feel free to message me with any specific queries :) 

 

 

Many thanks for taking the time to reply to my question, @MattTarrant your answer is very clear, so I will know when reading posts about teleconnections in future what this refers to.

I will have a look at the papers that you have given links to.

Thanks again, much appreciated.

Mike

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On 4/12/2018 at 23:19, MattTarrant said:

Seasonal Wavelength Change : With regard to the notion of teleconnections, this relates (as you mentioned) to jet stream undulation/amplitude.  Winter is characterized through a high poleward temperature gradient, resulting in increased upper atmospheric zonal winds (Jet Stream). High velocity upper atmospheric winds rarely reflect themselves in a meridional (high amplitude) setup, partial reasoning at least why winter weather is dominated by interchangeable surface setups (Unsettled). In summer months, with the considerable weakening of the polar vortex the temperature gradient is far less pronounced, resulting in lower upper atmospheric zonal winds (Jet Stream). This can and usually translates to a more amplified pattern being seen in the upper winds. In short, summer is characterized by short wavelength (increased amplitude) jet stream (Slower Aswell) setups and this is reversed in winter months. 

A possible approach to this (for beginners), is to consider why blocked surface patterns gain so much interest in the winter period. It will have weak correlation with fanatical hopes of snowmageddon, but on a serious note it provides respite from the broad continuum of strongly zonal conditions. Wavelength changes can change more abruptly on reduced timescales, these being induced by changes in the global wind oscillation (GWO), MJO phases etc. 

An interesting line of thought, especially since the turn of the millennium regards an ever increasingly undulated jet stream in both winter & summer potentially related to arctic temperature sensitivity. Here are a few links to research papers for you : 

https://ams.confex.com/ams/94Annual/webprogram/.../Extended Abstract.pdf

http://iopscience.iop.org/article/10.1088/1748-9326/10/1/014005/pdf

 

Interesting answer, however wavelength and amplitude are separate distinct wave characteristics

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16 hours ago, Interitus said:

Interesting answer, however wavelength and amplitude are separate distinct wave characteristics

I never intended to directly define wavelength, my answer was portended to help Mike :) with his questions. 

Wavelength in it self is does not require much talk, I intended to discuss around the topic to help promote Mike's wider thinking. 

 

Edited by MattTarrant
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