Links regarding Dr Francis' meandering jet stream effects

[crandles]

http://www.bbc.co.uk/news/science-environment-26023166

[wili]

Not sure if this is the right thread for this, but I just noticed that, at the 10 hPa level, the polar vortex has now split in two.

http://earth.nullschool.net/#current/wind/isobaric/10hPa/orthographic=-94.05,77.28,279

At the 70 hPa, it is nearly in two, with a very odd configuration:

http://earth.nullschool.net/#current/wind/isobaric/70hPa/orthographic=-94.05,77.28,279

[idunno]

2 more...

http://www.thestar.com/news/world/2014/02/15/rapidly_warming_arctic_may_be_causing_our_polarvortex_winter.html

http://blogs.discovermagazine.com/imageo/2014/02/14/tale-of-two-extreme-storms/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A%20DiscoverBlogs%20%28Discover%20Blogs%29#.UwCMnrTrQ6I

[RaenorShine]

Just heard the Dr Francis on the BBC Radio news in the UK, and very high up the running order too.  it's great that this has been picked up by the mainstream media, even though I realize this is due to the standard 24 hour news methodology nowadays (blanket coverage of event, followed by endless human interest vignettes and analysis afterwards).  This would not have been news without the storms, but the word needs to be got out wherever we can.

The BBC have also put together a video piece on the story with an interview with Dr Francis. http://www.bbc.co.uk/news/science-environment-26214377

As a weather layman, I first heard of Dr Francis' work after Hurricane Sandy, and since the Northern Hemisphere Weather seems to be doing an excellent job of proving the theory all by itself.  It is worrying what is going to happen next though as agriculture in particular is going to have issues with sticky weather.

[Apocalypse4Real]

I picked this up yesterday and blogged on it briefly, including the jet stream meandering of yesterday from 10 mb to the surface.

Here is the meandering mess at 500 mb for the NH.

See: http://a4rglobalmethanetracking.blogspot.com/2014/02/meandering-jet-streams-jennifer-francis.html

[crandles]

These have been posted before but it took me a while to find them so I set up this thread for such links.

Does Arctic Amplification Fuel Extreme Weather in Mid-Latitudes?
http://climatestate.com/2013/05/03/does-arctic-amplification-fuel-extreme-weather-in-mid-latitudes/
16 min video by Dr Francis

Full version

1hr 24 min

[RaenorShine]

I'll add this one also, actual presentation starts around 1hr in (this was a live stream of the event and they haven't cut the beginning off)

Climate Desk Live 06/06/13: The Alarming Science Behind Climate Change’s Increasingly Wild Weather

Stu Ostro and Dr Jennifer Francis
http://climatedesk.org/2013/05/climate-desk-live-060613-the-alarming-science-behind-climate-changes-increasingly-wild-weather-3/

[Jim Hunt]

A recent post on Andrew Revkin's Dot Earth blog now includes a long comment from Jennifer Francis:

http://dotearth.blogs.nytimes.com/2014/02/14/global-warming-winter-weather-and-the-olympics-five-leading-climate-scientists-weigh-in/

The Arctic/mid-latitude linkage hypothesis proposed [in] our paper is clearly in only in the early stages of research. Carefully designed modeling experiments and additional years of real-world data are needed to confirm it or not. To me, the ample discussion this idea has generated is not a “distraction,” but rather a trigger of a great deal of new research and healthy scientific discussion.

[wili]

Thanks for the link. The Green reply is interesting. Has that Cohen paper been discussed here somewhere and I missed it?

[idunno]

Hi wili,

Not that I'd noticed, so...

http://forum.arctic-sea-ice.net/index.php/topic,751.0.html

New topic- WACCy Science

[Jim Hunt]

Has that Cohen paper been discussed here somewhere and I missed it?

I don't recall Cohen's latest paper being discussed in detail, but Chris Reynolds in particular has mentioned his work on a regular basis. Maybe start here?

http://neven1.typepad.com/blog/2012/03/wacc-overview.html

[ChrisReynolds]

Jim,

I have indeed blogged rather a lot on Cohen.
https://www.google.co.uk/#q=dosbat+judah+cohen&safe=off

Probably the best starting point is here:
http://dosbat.blogspot.co.uk/2011/12/cold-winters-arctic-connection.html
His papers are here:
http://web.mit.edu/jlcohen/www/papers.html

Sh*t loads of Jennifer Francis here.
http://marine.rutgers.edu/~francis/pubs_10-05.html

[RaenorShine]

Thanks to TenneyNaumer on the Blog for this link.

Jennifer Francis and Kevin Trenberth on Inquiring Minds today:

http://www.motherjones.com/environment/2014/02/inquiring-minds-jennifer-francis-kevin-trenberth-jet-stream-winter

[idunno]

Peter Sinclair has posted 5 videos on the ongoing research and counter-arguments, here...

http://climatecrocks.com/2014/04/05/the-weekend-wonk-a-theory-so-cutting-edge-its-hard-to-prove/

[Jim Hunt]

And as I've just attempted to point out to Peter Sinclair, don't forget James Screen:

http://econnexus.org/does-the-arctic-sea-ice-influence-weather-in-the-south-west/

This study has provided evidence of a causal link between observed Arctic sea ice changes, the large-scale atmospheric circulation and increased summer Northern European Precipitation.

[idunno]

There follows a writeup from Masters of Wang et al's new paper, which directly links the CA drought to AGW...

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2665

...and concludes with a score of links to other papers, by Francis, by Li, by Screen; and so on.

[RaenorShine]

Just found a new lecture (23 October 2014) on Youtube.  Nothing really new, but brings further examples from earlier this year into it ( Polar Vortex, UK floods and California Drought.

Hopefully of interest!

Introduction

Part 1

Part 2

Part 3

Q&A

[BornFromTheVoid]

A new paper of Arctic Amplification and the effects on mid latitude weather.

The weakening summer circulation in the Northern Hemisphere mid-latitudes

Rapid warming in the Arctic could influence mid-latitude circulation by reducing the poleward temperature gradient. The largest changes are generally expected in autumn or winter but whether significant changes have occurred is debated. Here we report significant weakening of summer circulation detected in three key dynamical quantities: (i) the zonal-mean zonal wind, (ii) the eddy kinetic energy (EKE) and (iii) the amplitude of fast-moving Rossby waves. Weakening of the zonal wind is explained by a reduction in poleward temperature gradient. Changes in Rossby waves and EKE are consistent with regression analyses of climate model projections and changes over the seasonal cycle. Monthly heat extremes are associated with low EKE and thus the observed weakening might have contributed to more persistent heat waves in recent summers.

http://www.sciencemag.org/content/early/2015/03/11/science.1261768.abstract?sid=aadd8013-fde3-4f82-adbd-ca45ae6870fe

A good overview here http://www.carbonbrief.org/blog/2015/03/arctic-warming-linked-to-intense-summer-heatwaves-in-the-northern-hemisphere/

[DavidR]

A new paper of Arctic Amplification and the effects on mid latitude weather.

The weakening summer circulation in the Northern Hemisphere mid-latitudes

Rapid warming in the Arctic could influence mid-latitude circulation by reducing the poleward temperature gradient. The largest changes are generally expected in autumn or winter but whether significant changes have occurred is debated. Here we report significant weakening of summer circulation detected in three key dynamical quantities: (i) the zonal-mean zonal wind, (ii) the eddy kinetic energy (EKE) and (iii) the amplitude of fast-moving Rossby waves. Weakening of the zonal wind is explained by a reduction in poleward temperature gradient. Changes in Rossby waves and EKE are consistent with regression analyses of climate model projections and changes over the seasonal cycle. Monthly heat extremes are associated with low EKE and thus the observed weakening might have contributed to more persistent heat waves in recent summers.

http://www.sciencemag.org/content/early/2015/03/11/science.1261768.abstract?sid=aadd8013-fde3-4f82-adbd-ca45ae6870fe

A good overview here http://www.carbonbrief.org/blog/2015/03/arctic-warming-linked-to-intense-summer-heatwaves-in-the-northern-hemisphere/

Interesting paper which suggests a mechanism that  is reducing the impact of hurricanes and cyclones, a measure often quoted by contrarians  as 'evidence' that  AGW is not living up to the predictions.

[jai mitchell]

It should be noted here that the talking point of denialists regarding hurricanes is a complete fabrication as the projections of future hurricane activity in the models are inconclusive with regard to the numbers of hurricanes.  Many models show a large increase in upper altitude wind shear which works to suppress hurricane activity.  However, what the models DO show is that when the hurricanes do form that they will move further north and be more powerful with rising ocean surface temperatures.

[Jim Hunt]

The Melting Arctic and Mid-latitude Weather Patterns: Are They Connected?

Overland, Francis et al.

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-14-00822.1

The quantitative impact of Arctic change on mid-latitude weather may not be resolved within the foreseeable future, yet new studies of the changing Arctic and subarctic low frequency dynamics, together with additional Arctic observations, can contribute to improved skill in extended-range forecasts as planned by the WMO Polar Prediction Program (PPP).

[crandles]

Evidence for a wavier jet stream in response to rapid Arctic warming
http://iopscience.iop.org/1748-9326/10/1/014005/article
Jennifer A Francis and Stephen J Vavrus

Abstract
New metrics and evidence are presented that support a linkage between rapid Arctic warming, relative to Northern hemisphere mid-latitudes, and more frequent high-amplitude (wavy) jet-stream configurations that favor persistent weather patterns. We find robust relationships among seasonal and regional patterns of weaker poleward thickness gradients, weaker zonal upper-level winds, and a more meridional flow direction. These results suggest that as the Arctic continues to warm faster than elsewhere in response to rising greenhouse-gas concentrations, the frequency of extreme weather events caused by persistent jet-stream patterns will increase.

[RaenorShine]

New lecture from Dr Jennifer Francis on 21 January 2015 at the Storm Center Weather and Climate Summit.



The StormCenter Communications Youtube channel this is hosted on has videos of all the weeks sessions being uploaded as set out in their agenda http://www.stormcenter.com/wxcsummit/agenda.html. Well worth a browse for fairly accessible overviews of recent weather and climate research.

[BornFromTheVoid]

A few to add to this ol' thread


Persistent shift of the Arctic polar vortex towards the Eurasian continent in recent decades

The wintertime Arctic stratospheric polar vortex has weakened over the past three decades, and consequently cold surface air from high latitudes is now more likely to move into the middle latitudes1, 2, 3, 4, 5. However, it is not known if the location of the polar vortex has also experienced a persistent change in response to Arctic climate change and whether any changes in the vortex position have implications for the climate system. Here, through the analysis of various data sets and model simulations, we show that the Arctic polar vortex shifted persistently towards the Eurasian continent and away from North America in February over the past three decades. This shift is found to be closely related to the enhanced zonal wavenumber-1 waves in response to Arctic sea-ice loss, particularly over the Barents–Kara seas (BKS). Increased snow cover over the Eurasian continent may also have contributed to the shift. Our analysis reveals that the vortex shift induces cooling over some parts of the Eurasian continent and North America which partly offsets the tropospheric climate warming there in the past three decades. The potential vortex shift in response to persistent sea-ice loss in the future6, 7, and its associated climatic impact, deserve attention to better constrain future climate changes.

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3136.html


Media report of the study: Dreaded Polar Vortex May Be Shifting. As the Arctic wind pattern migrates toward Europe it could allow frigid air to descend upon the U.S. https://www.scientificamerican.com/article/dreaded-polar-vortex-may-be-shifting/

-----------------------

ARCTIC AMPLIFICATION: DOES IT IMPACT THE POLAR JET STREAM?

It has been hypothesised that the Arctic amplification of temperature changes causes a decrease in the northward temperature gradient in the troposphere, thereby enhancing the oscillation of planetary waves leading to extreme weather in mid-latitudes. To test this hypothesis, we study the response of the atmosphere to Arctic amplification for a projected summer sea-ice-free period using an atmospheric model with prescribed surface boundary conditions from a state-of-the-art Earth system model. Besides a standard global warming simulation, we also conducted a sensitivity experiment with sea ice and sea surface temperature anomalies in the Arctic. We show that when global climate warms, enhancement of the northward heat transport provides the major contribution to decrease the northward temperature gradient in the polar troposphere in cold seasons, causing more oscillation of the planetary waves. However, while Arctic amplification significantly enhances near-surface air temperature in the polar region, it is not large enough to invoke an increased oscillation of the planetary waves.

http://www.tellusa.net/index.php/tellusa/article/view/32330

[idunno]

More from the Guardian...

https://www.theguardian.com/environment/2016/dec/19/arctic-ice-melt-already-affecting-weather-patterns-where-you-live-right-now

[crandles]

Some models do better than others at representing Jet Stream.

http://link.springer.com/article/10.1007/s00382-016-3308-z

Atmospheric modes of variability relevant for extreme temperature and precipitation events are evaluated in models currently being used for extreme event attribution. A 100 member initial condition ensemble of the global circulation model HadAM3P is compared with both the multi-model ensemble from the Coupled Model Inter-comparison Project, Phase 5 (CMIP5) and the CMIP5 atmosphere-only counterparts (AMIP5). The use of HadAM3P allows for huge ensembles to be computed relatively fast, thereby providing unique insights into the dynamics of extremes. The analysis focuses on mid Northern Latitudes (primarily Europe) during winter, and is compared with ERA-Interim reanalysis. The tri-modal Atlantic eddy-driven jet distribution is remarkably well captured in HadAM3P, but not so in the CMIP5 or AMIP5 multi-model mean, although individual models fare better. The well known underestimation of blocking in the Atlantic region is apparent in CMIP5 and AMIP5, and also, to a lesser extent, in HadAM3P. Pacific blocking features are well produced in all modeling initiatives. Blocking duration is biased towards models reproducing too many short-lived events in all three modelling systems. Associated storm tracks are too zonal over the Atlantic in the CMIP5 and AMIP5 ensembles, but better simulated in HadAM3P with the exception of being too weak over Western Europe. In all cases, the CMIP5 and AMIP5 performances were almost identical, suggesting that the biases in atmospheric modes considered here are not strongly coupled to SSTs, and perhaps other model characteristics such as resolution are more important. For event attribution studies, it is recommended that rather than taking statistics over the entire CMIP5 or AMIP5 available models, only models capable of producing the relevant dynamical phenomena be employed.