Skeptical Science contributor John Mason has outdone himself this time - which says a lot after his great pieces on Arctic methane and other subjects - by writing a comprehensive article about the jet stream, what it is, what it does and why that is important. Here's the introduction and table of contents, but I'd advise everyone to go read the whole thing over at Skeptical Science:
A Rough Guide to the Jet Stream:
what it is, how it works and how it is responding to enhanced Arctic warmingPosted on 22 May 2013 by John Mason
Barely a week goes by these days in the Northern Hemisphere without the jet stream being mentioned in the news, but rarely do such news items explain in detail what it is and why it is important. As a severe weather photographer this past 10+ years, an activity which requires successful DIY forecasting, I've had to develop an appreciation into what makes it tick. This post, then, is a start-from-scratch primer based on that knowledge plus some valuable assistance from academia into where the current research is heading. Because of its length and breadth of coverage, I've broken it up into bookmarked sections for easy reference: to come back here click on 'back to contents' in each instance.
Contents:
Earth's Troposphere - an introduction
Weather systems aloft - the Polar Front and the jet stream
Waves on the jet stream - upper ridges and troughs
Positive vorticity - a driver of severe weather - and the jet stream
Wind-shear - a driver of severe weather - and the jet stream
Jetstreak development along the jet stream - a driver of severe weather
Northern Hemisphere atmospheric circulation patterns: the Arctic and North Atlantic Oscillations
Climate change and the future: how will the jet steam and pressure-patterns respond?
Um , "slightly" off topic but there is a world wide march against Monsanto tomorrow. https://www.rebelmouse.com/MarchAgainstMonsanto/
Posted by: Fufufunknknk | May 24, 2013 at 13:58
Oh, Jeez, sorry for that. I hit post instead of preview. I couldn't get typepad to reduce the image and was playing with the HTML.
Nevin, if you want to edit or remove this post, no worries. It is, ahem, "slightly" off taopic anyways.
Posted by: Fufufunknknk | May 24, 2013 at 14:00
No prob, Fufu. Monsanto is always ontopic.
People who want to see the full image: right-click it and pick 'view image'.
Posted by: Neven | May 24, 2013 at 14:15
Neven....thank you for linking to this article. I learned more about weather in the last hour than I've previously accumulated in 57 years.
Posted by: Shared Humanity | May 24, 2013 at 15:38
Speaking of the jet stream getting stuck over Greenland, melt there has gotten off to a slow start in 2013, however take a look at it today! http://nsidc.org/greenland-today/
This is the first day of large scale melting and it shows on the graph on right, showing a sudden spike upwards in melt compared to the average bell curve.
Posted by: Hans Gunnstaddar | May 24, 2013 at 20:52
The melting of the Polar ice and the changes it brings to the jet stream and the weather in Europe, Russia, China and the USA are, I believe, potentially the the fastest and most threatening tipping point there is. If the ice goes the weather is affected the same autumn and this leads to crop failure. My cousins are farmers in the UK and they are having a tough time now and it has hardly started,
I live in NZ now and we are affected less than most countries but we are not immune.
http://www.climateoutcome.kiwi.nz/
Posted by: Bob Bingham | May 25, 2013 at 07:18
John provides an excellent recitation of the conventional wisdom of modern weather theory. However, we know that modern weather theory does not always do a perfect job of predicting the weather. Weathermen claim natural variation, but there may be deeper reasons. For a very long time I have felt the conventional wisdom failed to adequately account for water vapor. See:
Makarieva, A. M., Gorshkov, V. G., Sheil, D., Nobre, A. D., and Li, B.-L.: Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics, Atmos. Chem. Phys., 13, 1039-1056, doi:10.5194/acp-13-1039-2013, 2013
The jet stream is wind. If you want to understand it, you have to (also)think about water vapor. Failure to fully address water vapor is another reason I am not happy with climate models.
This paper has been disparaged as having too much math. Weather (wind) is the internal work of a thermodynamic engine (Earth). And, math is the best language we have to describe thermodynamic processes.
Posted by: Aaron Lewis | May 25, 2013 at 16:01
In a former life, I taught Weather for the FAA Mandated annual Flight Dispatch Recurrent Training at a major airline. This is one of, if not the best overview of the jetstream and associated features I've ever seen, A little too advanced for the average Dispatcher - but as complete as any one of them would need.
Posted by: SteveG | May 25, 2013 at 17:17
If anybody would like a primer on the Coriolis force (mentioned in this piece and often misunderstood), there was an excellent and relatively short three part series in the journal 'Weather' in 2000 by Anders Persson. The links below provide links to the three free to download pdfs of the series, collectively titled 'Back to Basics.'
Part One
Part Two
Part Three
Posted by: PhilGChapman | May 26, 2013 at 04:18
Reposted from Arctic Sea Ice Forum:
Petermann Fjord Map Update.
I have added loads of images to the Petermann Fjord Map, primarily the shore line of Hall Land (north eastern shore).
Most important localities from Hall´s Grave (in Nares Strait) to Kap Egedesminde (a the top of Petermann Glacier) are covered, and more will come, I recognize most of the images are from 1984, but as the skeptics tells us it hasn't changed much ;), newer images is supplied by Andreas Muenchow who visited the area in 2012.
Some unofficial names are supplied by me, like First One To The Left Glacier, The Parallel Glaciers, Sankt Peders Vej Glacier, Hellerupvej Glacier(named after some streets in Hellerup, a district in the suburb of Copenhagen, and since both glaciers are located in Hellerup Land I find both names appropriate), Between A Rock And A Hard Place Glacier.
I also like to draw your attention to the inland calving that happened in 1984 or probably earlier, it is called Inland Calvin Site on the map and it is located between the tops of Steensby Glacier and Ryder Glacier in N. P. Johansen Land. It is an impressive piece of demolition work, to say it at least.
Please come and explore at:
https://mapsengine.google.com/map/u/0/edit?pli=1&mid=zbdKKg4fRHYo.kjkUmepfXc9A
Posted by: Espen Olsen | May 26, 2013 at 12:28
Thanks for the Coriolis primer, Phil! I was aware of the insufficiency of the "Hadleian" explanation (which I learned decades ago from a prominent Canadian meteorologist, then my father-in-law), but didn't have a more sufficient replacement.
The lack was an infrequent, yet recurring, annoyance!
Posted by: Kevin McKinney | May 26, 2013 at 14:50
Glad it was of interest Kevin. I thought the pieces were well written and clear; and I always appreciate historical context.
Posted by: PhilGChapman | May 27, 2013 at 15:27