What’s going under?

From a Usenet thread. …

A weather fan from the usenet group: uk.sci.weather wrote:

Originally posted by Les Hemmings:

Europe basked in unusually warm weather in medieval times – so much so that
wine was produced in England – but why has been open to debate. Now the
natural climate mechanism that caused the mild spell seems to have been
pinpointed.

The finding is significant today because, according to Valerie Trouet at the
Swiss Federal Institute for Forest, Snow, and Landscape Research in
Birmensdorf, the mechanism is not now of sufficient strength to explain
current warming.

The finding scuppers one of the favourite arguments of climate-change
deniers. If Europe had temperature increases before we started emitting
large amounts of greenhouse gases, the theory goes, then maybe the current
global warming isn't caused by humans, either.

To work out what the global climate was doing 1000 years ago during the
so-called "Medieval Warm Period", Trouet and colleagues started by looking
at the annual growth rings of Moroccan Atlas cedar trees and of a stalagmite
that grew in a Scottish cave beneath a peat bog. This revealed how dry or
wet it has been in those regions over the last 1000 years.

The weather in Scotland is highly influenced by a semi-permanent pressure
system called the Icelandic Low, and that in Morocco by another called the
Azores High. "So by combining our data, which showed a very wet medieval
Scotland and very dry Morocco, we could work out how big the pressure
difference between those areas was during that time," says Trouet.

More….

Originally posted by Alastair McDonald:

They say:
"According to Trouet, a Pacific La Niña mode and a positive NAO mode could have reinforced each other in a positive feedback loop and this could explain the stability of the medieval climate anomaly."

Positive feedback loops are inherently unstable. It is negative feedback loops which are stable.

But even allowing for that being a slip by Trouet or the reporter, when they meant a negative feedback loop, there is still another fundamental error in their reasoning. If the MWP was caused by a change in the NAO or ENSO, what caused that? If it was not an increase in CO2 then the fallacious argument of the deniers still stands. The last max in global temperatures occurred during the 1998 El Nino.

The normal mode for the North Atlantic is positive where Lows are low and Highs are high and the weather is given to alternating periods of wet and dry whos duration depends on the times of the phases, how closely they match each other and how they interact.

A series of closely matched phases is broken by a spate of weather that is out of sequence with the time of the phase because of a severe tropical storm or because of an impending earthquake.

Something I'd consider impossible to decipher with statistics. But then a few decades back I'd have thought what I now consider fact (above) to be impossible.

Two years ago I'd have said quantifying the power in a convergence of low pressure systems and comparing them to the power of severe earthquake trains would also be impossible.

It turns out this latter isn't even difficult.

The severity of a Mag 7 earthquake for example, is not the severity of two Mag 3.5 earthquakes because of the amplifaction effect of a train of waves meeting to produce such large magnitudes.

A large quake is no more than the convergence of several acoustic waves of moderate and even of no severity.

The earth is a sump of sounds and they scatter in all directions. Sometimes they overlap, that's all there is to earthquakes.

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6 thoughts on “What’s going under?

  1. If you like looking at the weather forecasts and they are not as bad as the British ones are on the TV these days you might keep a lookout for any convergence going on at about 05:30 today; 80 degrees from 5.1N. 127.2E. EDIT:My apologies to the ones I still disrespect because I have less to crow about. The arc I was looking at is 120 degrees./EDIT.That's an arc from Cape Horn to the Gulf of Gunea through the Sahara out through Portugal to Newfoundland at place called Hebron. South from there through Hudson Bay. (Shouldn't that be Lough Hudson?) to Thunder Bay, through La Paz Mexico and touching the tip of Baja (Cape St Lucas.) That's it then, except for Easter Island in the middle of the South Pacific gyre. I hate to look at the charts these days as they can become compulsive for me. Mag 6.3. 4th May 2009. 05:32 UTC. 5.1N. 127.2E. Philippines. http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/quakes_big.php As stated above, in my not humble at all opinion, the cause of earthquakes is exactly the same as the cause of convergence in the atmosphere -if I have understood the term "convergence" correctly.http://www.islandnet.com/~see/weather/elements/whatgoesup3.htm

  2. I'd be half tempted to try again if looking at the distance to Mt Redoubt hadn't already alerted me.I was doing stupid things all yesterday because of short term memory loss.Mt Redoubt near Kenai in Alaska is close to 80 degrees from the 6.3 epicentre.But nowhere near the 140 to 145 degrees from Mt Llaima. (38.7°S. 71.7°W.)

  3. Originally posted by Encyclopaedia.com:

    Quick Clays.The term ‘quick clay’ is used to describe fine-grained, relatively low-density soils that exhibit a dramatic reduction in strength when subjected to either shearing or shaking.The geotechnical term "sensitivity" is used to characterize these materials and is defined as the ratio of the shear strength in the undisturbed state to the shear strength in the fully remoulded state.Most clays exhibit some drop in strength when sheared, but in the case of quick clays sensitivities well above 50 are quite common, and values above 100 have been reported. Under conditions of rapid shearing the material is transformed in a matter of seconds from a rigid solid to a fluid-like mass.Such unusual behaviour is made possible by the build-up of high pore-water pressure within the moving mass, which itself is caused by a collapse of the low-density material as it is sheared. Since water is virtually incompressible, any reduction in volume caused by structural collapse will cause a large increase in pore pressure.When the pore pressure at a given depth is equal to the total overburden pressure, the frictional forces between the particles are close to zero, and as a consequence the material can behave as a fluid. This is the origin of the ‘quick’ condition.Although this behaviour can be induced in most soils by adding water and stirring, the crucial difference with quick clays is that a fluid-like state can be induced without increasing the natural water content.

    PAUL HANCOCK and BRIAN J. SKINNER. "quick clays." The Oxford Companion to the Earth. Oxford University Press. 2000. Encyclopedia.com. 6 Apr. 2009http://www.encyclopedia.com

  4. What role does confluence play in your world view?There's some significant confluence here today (see excerpt of today's Storm Prediction Centre Day One outlook synopsis below), with resulting weather uproar already ongoing and with more to come, and I was just wondering, since the SPC risk zone, for absolutely no geologic reasons whatsoever, happens to include two seismic high-risk zones, with the meteorological moderate-risk zone roughly corresponding to the East Tennessee Seismic Zone.Excerpt:SynopsisA closed Mid-Level Circulation is now in the process of forming within an amplifying trough in the southern branch of split polar flow off the southern California coast. and much of the [computer] model guidance is similar[ly] indicating that this feature will turn eastward across Southern California into the Lower Colorado Valley later today/tonight.As this occurs[, an] upper ridging appears likely to build through much of the Plains/Lower Mississippi Valley and central Gulf Coastal areas in the wake of the weakening remnants of the compact and vigorous “closed low” [a cyclone; an ellipse of low pressure contained in concentric rings from about 1016millibars to whatever, 850 mb is as low as most household barometers read] now progressing eastward into/through the Ozark Plateau. just how fast this latter system weakens to the south of a northern stream trough progged [programmed?] to dig across the Eastern Canadian Provinces and Upper Great Lakes Region is a bit uncertain. but it will encounter at least a somewhat more confluent regime between the northern and southern streams across the Lower Ohio/Tennessee Valleys into the Mid Atlantic States. Regardless, Low And Mid-Level Jet Streaks [500 millibar and 2 or 300 millibar heights] accompanying this feature are expected to remain strong and sufficiently sheared to support continuing severe potential as a moist and potentially unstable Gulf Return Flow develops through themid South And Northern Gulf States into the lee of the Southern Appalachians.Full outlook at:http://www.spc.noaa.gov/products/outlook/day1otlk.html(link will work for today, April 10th)The old equipment used only block capitals and nobody has had the sense to change it on the basis that if it ain't broke you don't need to fix it.Or perhaps backwards countries such as South Korea, Taiwan, Indonesia and Japan are so old fashioned with computing updates that they can't use anything else.Yes, right!There are archives for all of North America surface level pressures on the Canadian site. I have lost all my bookmarks in a reinstall. So I can’t post links yet.The same is true for San Francisco University’s website again my links have gone. They might be lower down on my Opera page.The Aleutians are exactly the same shape as the shore of the N American Rocky Mountains. Rat Island and nearby Fox are about where San Francisco would be if they were to swap places.When a confluence moves across North America it filters out the Low pressure into different wave sets but as they approach the east coast they may gather again. (They go even deeper over the North Atlantic Ridge south of the Denmark Straight where as many as 5 such Lows can be gathered very rarely but 2 or 3 are more than possible.)As I was saying: when a confluence moves across North America and approach the east coast there will be a confluence of seismic waves some 80 degrees from it. This may turn up in Chile or at the Rat Islands region. (I have a feeling that there is a twist to it regarding when it is an High or a Low pressure but as soon as I learn one thing I forget it in the pressure to explain what I think I have seen.)I think that it is High Pressure leaving from the Carolinas that does the Rat island quakes and the Fox Islands quakes are due to Lows or it may be something somewhat different.Then there is the business of other weather patterns leaving the same continent or entering at the same time. It's as complex as you want it to be and as straightforward as you have the time to look at it.I think god made it like that so we'd all have a chance of seeing it occurring.The thing is we needed to invent instant mass communications to go with extremely accurate widespread weather equipment. Which begs the question of what arthritics might have been able to do.I rather believe that Totem poles and May poles as with astronomical calendar setters like Stone Henge, would have been invented to aid farming -planting and harvesting as well as second guessing forthcoming weather types.It is a method widely used today in the southern States and in Australia to forecast good fishing times and days.I have no doubt it was well know globally in our early history.I just don't have the time and patience to follow all this stuff up.

  5. Interesting, I used to own a casio wristwatch and you could programe in lattitude and longitude to give you the moon phases relivant to where you were.This then indicated the best times to fish [if i remeber the display on the watch gave 1-5 tiny fish symbols] It was quite accurate, at the time that I owed the watch I was fishing in north Wales [off Anglesea] and there were 5 tiny fish symbols on the watch, I can not remeber the year or the date, but it was a spring tide and this is acnowleged as a good time to fish. The charter boat I was on yeilded a tremedous catch. Is It therefor possible to attatch lunar phases to weather forcasting?

  6. Yes. You can get charts for it.I was on a forum belonging to someone in one of the Carolina ports in the USA who wrote his own programme to do it.Lost it now with the reformat and stuff.I'll post it if I ever find it.

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