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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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Posted (edited)
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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What is the GSDM and how does it help with subseasonal weather forecasts? - A Review of This Presentation

This specialist "Teleconnections" thread was set up to examine and learn more about the main drivers and influences on the broader global weather patterns and how these drivers interact with each other and which are the more dominant ones. Some of the posts have already focused on the great importance of understanding the major role played by AAM (Atmospheric Angular Momentum) and the torques. Several of us have discussed the GSDM (Global Synoptic Dynamic Model) which was jointly developed by leading meteorological scientists Edward K Berry and Dr Klaus Weickmann while they were working at NOAA in the late 1990s and earlier years of this century. They also devised the GWO (Global Wind Oscillation) as a way of plotting and measuring the amounts of relative global AAM,  FT (frictional torque) and MT (mountain torque) at different phases of the cycle. They became leaders in this specialist research which has been used to assist in understanding impacts on global weather patterns and upcoming changes up to a few weeks ahead. 

Unfortunately, they left NOAA several years ago and it seemed that their vitally important work had ceased with a great loss to advances in meteorological science.  We have been trying to track them down and recently found an email address for Ed Berry. I sent Ed an email and I was delighted when he replied almost immediately. He explained that Klaus Weickmann retired several years ago. Ed Berry (Senior Weather-Climate Scientist) continues his excellent work on the GSDM and retains his lifelong passion to develop the model and its meteorological applications further. We have exchanged a few more emails with Ed and he is very supportive of the work that we are doing on this thread. I hope that we can persuade Ed to post on here in due course.

I asked Ed if he could assist us with obtaining past AAM, FT and MT data (which had been withdrawn from the NOAA Maproom archives) as well as more comprehensive current data and I explained to him that we had been in touch with Victor Gensini (Assistant Professor, Department of Geographic and Atmospheric Sciences, Northern Illinois University) who has been working  on and producing some of this missing data - several of our posts include examples of Victor's charts. Ed told me that he was in touch with Victor and they had discussed some of this work.  Victor hosted an AMS seminar recently (American Meteorology Society - Student Chapter,  College of DuPage, Chicago on 28th March, 2018) and Ed gave a one hour presentation on the GSDM (as shown in the title to this post). Ed emailed a  link to his presentation last week and I have already viewed it three times, learning a little more about the GSDM each time. He gave me full permission to review it on here. Firstly, here's the link to the presentation:    https://youtu.be/Cv5CblXbYuQ

It is a brilliant seminar with clear charts and explanations, ending with a question and answer session. For anyone wishing to learn more about AAM, the torques, the GWO and how they interact with other major teleconnections like phases of the ENSO (El Nino Southern Oscillation) and the MJO (Madden Julian Oscillation) then this is absolutely essential viewing. I also strongly recommend  this for more advanced viewers as well. The presentation is right up-to-date and includes the 2018 SSW (Sudden Stratospheric Warming) event and links to key issues like climate change. Much of the presentation is slanted towards the North American climate and US weather patterns but it has a global significance and includes impacts on both hemispheres. I show a small selection of the charts from Ed's presentation below to whet your appetite:

 ed1.thumb.PNG.ee988ae75134340f81506cdcd0d1661e.PNG ed2.thumb.PNG.2052a9e05041d9827fbc38002159df89.PNG ed3.thumb.PNG.e876fca5dee6eb0e19fab2b018398bb4.PNG ed4.thumb.PNG.9bdde0fbbd1637910371e0abeb510c42.PNG  ed5.thumb.PNG.abda5105d6c0099b520e0024f48882a0.PNG     

ed6.thumb.PNG.ec2206d2cd16dc4448ae84dbcc3e134f.PNG        ed7.thumb.PNG.dbd24ac556166052df3bcc606008cfff.PNG        ed8.thumb.PNG.c061ec7e1af78578145ff1684d87aadc.PNG       ed9.thumb.PNG.50828c66349244a751f5834d423d5428.PNG 

 

 ed10.thumb.PNG.67c67b5f4fb45c80801d3f3a0b3cda40.PNG       ed11.thumb.PNG.dd8cccec90b25f5868fad84db55af588.PNG      ed12.thumb.PNG.9809422e855029cc4bd4cfb4ee2b05a7.PNG        ed13.thumb.PNG.9a45c05d95672174dad1457f37fa389a.PNG

 

  ed14.thumb.PNG.5730a7db0c6700b5fbf2a07796301669.PNG  ed15.thumb.PNG.37af88d5a11c5ede7b566fee7d412d57.PNG    ed16.thumb.PNG.53324d4d5d40a9995230c319082e9932.PNG ed17.thumb.PNG.6dd6ffcbdc3af37fad9786e719716c79.PNG

 

Obviously one needs to follow the full presentation to see what is behind these charts. There is also a focus on several earlier events including winter 2012/13. I hope to have many more exchanges with Ed as well as with Victor..

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Posted (edited)

 

Edited by knocker

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Posted (edited)

H/t MV

Quote

The El Nino standing wave appears to have emerged with this most recent MJO passage across the Pacific. This is not a canonical east-based El Nino; it appears to be a basin wide event, which many call the Modoki. 2006 and 2009 are most recent events similar to today

El Nino influences the formation of low pressure systems over the Gulf Stream

Quote

Analysis of cyclone tracks and precyclogenesis flow conditions show us that El Niño can shift the preferred cyclogenesis position over the Gulf Stream which influences the cyclone's track across the North Atlantic.

Northern Europe is located at the end of the North Atlantic storm track and the low pressure systems that bring this area precipitation typically form above the Gulf Stream or at the southern tip of Greenland. A recent study published in the Journal of the Atmospheric Sciences, by Sebastian Schemm, Laura Ciasto, Camille Li and Nils Gunnar Kvamstø reveals how ENSO affects the formation of low pressure systems over the Gulf Stream area and consequently their tracks across the North Atlantic. The results are based on the analysis of the wintertime precyclogenesis flow across North America during three ENSO variants in an observation-constrained reanalysis dataset.
 

 

https://phys.org/news/2016-10-el-nino-formation-pressure-gulf.html

Edited by knocker

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