One of the most basic tenets of meteorology, The Norwegian Cyclone Model is getting a makeover. From the University of Manchester:
Taking a fresh look at the weather
Given the UK’s obsession with the weather, it would seem obvious that the basic understanding of how low pressure systems evolve has been known for a long time.
Instead, some of the biggest storms in the UK’s history, such as the Great Storm of October 1987, did not fit this basic understanding.
With groundbreaking research, Dr David Schultz, from The University of Manchester believes the way we learn about the weather is wrong and has been wrong for 90 years.
Writing in the journal Bulletin of the American Meteorological Society, Dr Schultz, along with his colleague Professor Geraint Vaughan, has worked out that the traditional model for how low pressure systems evolve is deeply flawed.
The model, used since the 1920s and devised by Norwegian meteorologists, is that when a storm occludes (evolves), it will automatically begin to weaken and pose little danger of severe weather.
However, argues Dr Schultz, this is not the case – occluded storms may well contain strong winds and regions of heavy precipitation.
Naturally, many in the public recognize that. The Great Storm of October 1987 and the Burns’ Day storm of January 1990 were both clear reminders: occluded, but still deadly. Dr Schultz’s new model addresses these weaknesses with the Norwegian model because the prior belief that occluded storms were weak could lead to poorly-informed predictions or forecasts.
Dr Schultz, from the University’s School of Earth, Atmospheric and Environmental Sciences, claims they now know that the deepening of a low pressure system is not dependent on when a cyclone occludes.
Specifically, the new model is called ‘wrap up’, to emphasize that the wind around the occluding cyclone wraps up the low pressure system into an anticlockwise-spiralling cloud pattern.
Dr Schultz said: “With this new interpretation of the occlusion process we can explain why not all low pressure systems occlude – the winds are not strong enough to wrap up the storm.
“The Norwegian model of low pressure systems served us well for many years, but it’s time to move on.
“This new model is better than the Norwegian model at explaining the available observations of the structure and evolution of occluded low pressure systems.”
Dr Schultz argues that how we teach about low pressure systems is wrong, and that textbooks, public information guides and models will need to be radically updated to ensure the next generation of meteorologists, as well as the public, are in possession of all the facts.
He added: “All books from postgraduate-level textbooks to basic weather books for the public need to be rewritten to convey the correct understanding. What we teach students in school needs to be changed. And forecasters need to be retrained to have this latest information.”
Another result of Dr Schultz’s research is a better explanation for the observed structure of storms. Previously, meteorologists believed that occluded cyclones and their associated fronts could tilt eastward with height or tilt westward with height, roughly in equal measure. This new research demonstrates that westward-tilting occluded fronts are rare and provides an explanation for why.
Dr Schultz added: “I hope that this model will help people understand the particular weather conditions associated with these potentially hazardous storms. Yet, this research shows how much more remains for us to learn about the weather around us.”
Notes for editors
The paper, Occluded fronts and the occlusion process: A fresh look at conventional wisdom,
by David M. Schultz and Geraint Vaughan, is available from the Press Office.
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Anthony, this has got to be the most non-story “revelation” I’ve seen out of a press-release ever…I don’t know anyone in my field that had such flawed conventional wisdom to begin with.
It’s also freely available at ametsoc.org – Click the publications link and perform an article search for the title listed in this article.
So the science wasn’t settled, then?
The Met Office has used nothing but the Norwegian model – proof is in the abject failure of its predictions. 37 Million Taxpayer Pounds and no success.
[ryanmaue: no, this isn’t remotely true. the “Norwegian model” is nothing more than a conceptual framework of understanding the extratropical cyclone evolution. it does not consist of numerical or mathematical proofs. If you note that the extratropical storm track ends in the North Atlantic near Norway, then dying or occluded systems were more likely to be observed in Norway. In 1922, their understanding of cyclone processes elsewhere was considerably hampered by their geography: they understood well the storm systems that actually went over their heads. They did not conceptualize other types of cyclone evolution that they had never observed. This isn’t a flaw per se. They accomplished a lot in terms of understanding weather with what few observations they indeed had.]
Oh model…..model….model, thou art doomed to fail.
I remember the 87 storm because I slept right through it and hundreds of thousands of trees the next day had been blown down. The 90 storm was more memorable as walking in 90mph winds was bad and the River Tees nearly flooded because of it.
However more interesting are flat line winds which we had in Memphis TN in 2003 called Hurricane Elvis it lasted only a few minutes but caused untold damage to the power supply in the city lasting a few weeks to repair. I watched that from a kitchen window at 6 am fortuitously enough. Three hours earlier and FEDEX would have lost 3 planes.
Having been through 4 hurricanes, including 2 real bastards, I will assure anyone that the model is wrong. I can well remember mini-tornadoes that were so scary that it gave all nature pause. Destroyed a reinforced house in front of my eyes in less than 10 seconds. (All four residents survived in the bath tub) These tornadoes were later to be found circling counter-clockwise to the hurricane. That was Iniki. Top wind measure by the Department of Defense was 227 miles per hour. They refused to allow publication of the result for some reason, even though it was generally known. But no, , no instrumentation , survived. Computers recorded over 230 before the exterior instrumentation went out, I was told by Navy people, but that was considered an artifact.
Anyone who wishes to understand meteorology and climate must read Marcel Leroux’s books, a French climatologist who died in 2008 and who has invented in the 80′ the “Mobile Polar High concept”. MPH are large discs of cold and high pressure air (1000 to 1500 m thick) originating from the polar regions on their way towards the equator. They are the cause for everything. Storms are just the vortex created by the organisation of the void left at the leading edge of MPHs. That is why depressions originate at low altitude, and not at high altitude as most meteorologist believe (jet stream has really no importance in that matter)
http://lcre.univ-lyon3.fr/climato/amp.htm
(in french)
http://lcre.univ-lyon3.fr/climato/AFrenchclimatesceptic.pdf
Marcel Leroux explains clearly why then the Norvegian model is flawed, since storms at these latitude can not create themselves, but are the consequence of travelling MPH. These MPH are also driven by relief because of their small thickness, explaining all the regional climate. He also explains why El Nino et La Nina are also the consequence of MPHs. Marcel Leroux was also a sceptic since he very early assess irrelevancy of climatic model because they do not take into account the actual general circulation lacking MPG behaviour.
Marcel Leroux deserves a fresher look. His books are really amazing.
Thierry
Observations don’t match forecasts.
The models are wrong (again).
In many respects the Mobile Polar High concept of Leroux is very useful.
The conventional model for depressions provides that the energy for the spinning (and thus the overall wind strength) is dictated by the temperature differentials between the air masses mixing within the depression. The idea is that the air masses have different densities and so respond differentially to the Earth’s rotation to start the mixing and spinning. On that basis it is logical that once the warm sector has all been lifted aloft then those differentials decline and the depression should begin to wind down.
However that never did account for many depressions that continued to intensify after occlusion had been completed. There are many such. I have long been aware of that deficiency in the standard model.
The Leroux concept is that the movement of the MPH provides the initial ‘push’ to start the spinning and would be capable of adding even more of a push later on even after completion of the occlusion process.
That is in fact implicit in my description of a top down solar effect altering the vertical temperature profile of the atmosphere so as to change the intensity of the polar vortex and the size and position of the polar high pressure cells which then behave as Leroux suggests.
Furthermore ‘hands on’ weather forecasters have been taking the phenomenon into account for decades. It is only recently that the idea seems to have lost ground with over reliance on models and a consequent loss of practical experience.
I remember many occasions in the past when Michael Fish and other well known broadcast meteorologists would explain the powerful northerly behind a passing deep depression as being exacerbated by a gowing high pressure cell giving the winds an additional impetus despite an obviously occluded front.
Dr. Schultz may be right but he has discovered nothing new. Rather, he is re stating knowledge that had becme lost.
The really important point is why those polar high pressure cells ebb, flow and shift in the first place. That is where I think I am ahead of the game.
If my memory serves me correctly and the 1987 Storm is the UK one which Mr Fish got so disastrously wrong then it was made much more powerful because 2 low pressure systems came together when the 1st one stalled just off the south coast and was caught up by the 2nd system. This is very rare as nearly all systems transit over the UK in procession and are quite widely spaced.
I remember a recent article about someone who proposed that “everything you know about static electricity is wrong” and proceeded to impute all sorts of nonsense to the conventional wisdom under the guise of correcting the myths.
( here we go: http://www.sciencemag.org/content/early/2011/06/22/science.1201512 to wit:
” it has been assumed that such contact charging derives from the spatially homogeneous material properties (along the material’s surface) and that within a given pair of materials, one charges uniformly positively and the other negatively.” which is the authors pretending that their own facile assumptions, based on something they learned in elementary school, have universal import)
This definitely has the same scent.
Having watched a “dying” sub-tropical cyclone rip off roofs and trundle a 250 ton container crane along its track against its brakes, then tip it off the end of the quay, I will only say that extreme weather is not something many models even come close to. In the storm I witnessed the Harbour Control’s anemometer went off the scale – then literally blew away. I can tell you it was no fun trying to cut our way into the 200 gt Pilot Launch trapped beneath the crane as the tide rose with the crew trapped below the crushed superstructure in those winds either.
The ‘forecast’ for that day predicted ‘strong winds’ – so I guess they got that bit right. This was in 1987 in South Africa and I recall that a Meteorologist said at the time that they could not really predict what these storms would do in their ‘decay’ phase.
after these models the weather will still be wrong
New research leads to update to what is thought to be how things work ,, normal science in action.
Now lets remember there are those demanding that in one area this should not be case as its ‘settled’ beyond any challenge.
Ah Pat, 4 people in a bathtub ?
You know, just curious.
Chrs JJ
Thanks mods, Anthony and posters … as always.
In whatever way the cyclones form, the shapes of the resulting logarithmic spirals appears to be consistent. Here is the Icelandic low pressure system used to illustrate the article.
http://homepages.woosh.co.nz/zanzibar/
Thank you Thierry, I am so glad you are recommending Marcel Leroux’s work, I have mentioned them on several occasions when his work is proven be someone else. I think it is essential when observing Geos satellites and one can clearly follow the origins of cyclonics and anti-cyclonics.
Oh it is climate change LOL. Storms are storms. 1 million trees were destroyed in unusual
storm I think they are referring to the 1987 one in UK. But what about the one in 1953.
It flooded Canvey Island, and other parts of the East Coast of England and Scotland. Holland
suffered worse. Ships were lost. Google 1953 Great Storm.
I do sympathize with people who have experienced a hurricane. While living in Bermuda in 1969
we did experience being on the edge of the hurricane belt. It was hazardous to drive as most of their roads are on the sea front, and waves were washing up over the small cars and the winds so high they threatened to push you over. However, the houses are very strong made from blocks of limestone. But the roar of the wind? And of course some of the flowers were killed from sea spray thrown up.
Anyway Norway is unique. It is a land of the midnight sun and polar nights. 22 hours of day and twilight in the summer months and darkness of polar nights in winter.
pat says:
August 3, 2011 at 12:05 am
The post is about extratropical storms which form at frontal boundaries and behave very differently than tropical storms. A storm can change between the two types, commonly a tropical storm goes extratropical as it moves over cooler water. That transition is marked by broadening of the wind field loss of the warm core and eyewall, and various other things. I haven’t looked at the paper but I doubt it has anything to add to tropical storm knowledge (and it sounds like it has little to add to extratropical storm knowledge per Ryan).
I think I’m familiar with the Iniki wind guest, but I thought it was stronger and would have supplanted the Mt Washington wind record (which has been supplanted by a typhoon). Oops, no. That was 236 mph on Guam where “As investigation of the Guam report proceeded, it became evident that the claim of a 236 mile per hour gust could not be substantiated.”
Except for record temperatures at Hawaii airports (/sarc), most remarkable records are subject to critical review. The Mt Washington record certainly was, and the Paka gust was analyzed with almost forensic detail. They found evidence that before the anemometer blew away, broken guy wires allowed the anemometer to swing back and forth, resulting in too high readings. The Iniki reading may have involved the same physics.
See http://www.mountwashington.org/about/visitor/recordwind-1997challenge.php for all the details.
This paper by Makarieva et al is relevant to the issue also, imo.
Uh oh…dissing the Norwegian model! There goes their Nobel Prize…
\sarc
The amount of ego bugs me, particularly in light of Dr Maue’s statement about the state of the art understanding. Either the guy is seriously delusional about his own importance (ALL books need to be rewritten?), grossly uniformed or playing to the crowd for tenure’s sake.
However one cuts it – it speaks generally why I don’t trust academics…. and why we’re here wrt CAGW.
a must see
prof plimer